Hydraulic fracture height limits and fault interactions in tight oil and gas formations

NASA Astrophysics Data System (ADS)

Flewelling, Samuel A.; Tymchak, Matthew P.; Warpinski, Norm

2013-07-01

widespread use of hydraulic fracturing (HF) has raised concerns about potential upward migration of HF fluid and brine via induced fractures and faults. We developed a relationship that predicts maximum fracture height as a function of HF fluid volume. These predictions generally bound the vertical extent of microseismicity from over 12,000 HF stimulations across North America. All microseismic events were less than 600 m above well perforations, although most were much closer. Areas of shear displacement (including faults) estimated from microseismic data were comparatively small (radii on the order of 10 m or less). These findings suggest that fracture heights are limited by HF fluid volume regardless of whether the fluid interacts with faults. Direct hydraulic communication between tight formations and shallow groundwater via induced fractures and faults is not a realistic expectation based on the limitations on fracture height growth and potential fault slip.

Can the height of fall predict long bone fracture in children under 24 months?

PubMed

Hansoti, Bhakti; Beattie, Tom

2005-12-01

It can be difficult to determine the exact mechanism of injury in infants and babies aged 24 months and under. Falls are the most common mechanism of injury in children. The purpose of this study is to identify the relationship between reported height of fall and long bone fracture. All children aged under 24 months who sustained a fracture (in the year 2003) were identified prospectively on the departmental fracture database. These children were matched for age and sex with children identified as having fallen but not having sustained a fracture. Sixty-three children aged 24 months and under were studied. The median height of fall in this group was 48 cm and that in the control group was 20 cm, P<0.001. A significant correlation was observed between the height of fall (cm) and severity of injury (Pearson's correlation coefficient=0.255). Receiver operating characteristic analysis indicates that the likelihood of significant fracture requiring admission and/or manipulation under anaesthesia occurs with a fall from a height of 56 cm [sensitivity 80% (confidence interval 29-97%), specificity 79% (confidence interval 70-86%)]. It was not possible to identify a height at which the risk of any fracture injury became significantly more likely. Height of fall is only one factor that must be considered in dealing with fracture injury in children aged 24 months or under. However, significant injury presenting with falls from less than 50 cm should be critically evaluated.

An evaluation of flexible intramedullary nail fixation in femoral shaft fractures in paediatric age group.

PubMed

Kumar, Sanjay; Roy, Sandip Kumar; Jha, Amrish Kumar; Chatterjee, Debdutta; Banerjee, Debabrata; Garg, Anant Kumar

2011-06-01

Sixty-two femoral shaft fractures in 60 patients treated by elastic intramedullary nailing with mean age of the patients being 9.2 years (range 5 years to 12 years) and average follow-up of 15 months (range 7 months to 60 months) are evaluated. Twenty-eight fractures were fixed with titanium elastic nail while 34 fractures were fixed with Enders nail. There were 40 midshaft fractures, 18 proximal femoral and 4 were fractures of distal third. Fracture patterns were transverse in 35, short oblique in 14 cases and 13 were spiral fractures. Mean age of union in this series was 17 weeks (range 12 weeks to 28 weeks). Ten cases had complications, 5 had nail tip irritation, 3 varus or valgus malalignment and 2 had delayed union. In this series, we did not have any non-union, refracture, limb length discrepancy or any major infection. The result demonstrates 100% union rate irrespective of the age, weight and height of the patient. Regardless of the site of fracture and their pattern, it united every time with elastic nail fixation. We did not find and mismatch in the results of fractures stabilised with titanium elastic nail with that of elastic stainless steel nail.

Comparison of plantar flexor musculotendinous stiffness, geometry, and architecture in male runners with and without a history of tibial stress fracture.

PubMed

Pamukoff, Derek N; Blackburn, J Troy

2015-02-01

Greater lower extremity joint stiffness may be related to the development of tibial stress fractures in runners. Musculotendinous stiffness is the largest contributor to joint stiffness, but it is unclear what factors contribute to musculotendinous stiffness. The purpose of this study was to compare plantar flexor musculotendinous stiffness, architecture, geometry, and Achilles tendon stiffness between male runners with and without a history of tibial stress fracture. Nineteen healthy runners (age = 21 ± 2.7 years; mass = 68.2 ± 9.3 kg; height = 177.3 ± 6.0 cm) and 19 runners with a history of tibial stress fracture (age = 21 ± 2.9 years; mass = 65.3 ± 6.0 kg; height = 177.2 ± 5.2 cm) were recruited from community running groups and the university's varsity and club cross-country teams. Plantar flexor musculotendinous stiffness was estimated from the damped frequency of oscillatory motion about the ankle follow perturbation. Ultrasound imaging was used to measure architecture and geometry of the medial gastrocnemius. Dependent variables were compared between groups via one-way ANOVAs. Previously injured runners had greater plantar flexor musculotendinous stiffness (P < .001), greater Achilles tendon stiffness (P = .004), and lesser Achilles tendon elongation (P = .003) during maximal isometric contraction compared with healthy runners. No differences were found in muscle thickness, pennation angle, or fascicle length.

Anatomical and Functional Recovery of Intracapsular Fractures of the Mandibular Condyle: Analysis of 124 Cases after Closed Treatment

PubMed Central

Lee, Jong-Sung; Jeon, Eun-Gyu; Seol, Guk-Jin; Choi, So-Young; Kim, Jin-Wook; Kwon, Tae-Geon; Paeng, Jun-Young

2014-01-01

Purpose: The purpose of this study is to evaluate the influence of intracapsular fracture lines of the mandibular condyle on the anatomical and functional recovery after non-surgical closed treatment. Methods: Clinical and radiological follow-up of 124 patients with intracapsular fractures of the mandibular condyle was performed after closed treatment between 2005 and 2012. The intracapsular fractures were classified into three categories: type A (medial condylar pole fracture), type B (lateral condylar pole fracture with loss of vertical height) and type M (multiple fragments or comminuted fracture). Results: By radiological finding, fracture types B and M lost up to 24% vertical height of the mandibular condyle compared to the height on the opposite side. In Type M, moderate to severe dysfunction was observed in 33% of the cases. Bilateral fractures were significantly associated with the risk of temporomandibular joint (TMJ) dysfunction in fracture types A and B. Bilateral fracture and TMJ dysfunction were not statistically significantly associated in type M fractures. Conclusion: Most of the mandibular intracapsular condylar fractures recovered acceptably after conservative non-surgical treatment with functional rehabilitation, even with some anatomical shortening of the condylar height. The poor functional recovery encountered in type M fractures, especially in cases with additional fracture sites and bilateral fractures, points up the limitation of closed treatment in such cases. PMID:27489844

HSTRESS: A computer program to calculate the height of a hydraulic fracture in a multi-layered stress medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.

A computer code for calculating hydraulic fracture height and width in a stressed-layer medium has been modified for easy use on a personal computer. HSTRESS allows for up to 51 layers having different thicknesses, stresses and fracture toughnesses. The code can calculate fracture height versus pressure or pressure versus fracture height, depending on the design model in which the data will be used. At any pressure/height, a width profile is calculated and an equivalent width factor and flow resistance factor are determined. This program is written in FORTRAN. Graphics use PLOT88 software by Plotworks, Inc., but the graphics software mustmore » be obtained by the user because of licensing restrictions. A version without graphics can also be run. This code is available through the National Energy Software Center (NESC), operated by Argonne National Laboratory. 14 refs., 21 figs.« less

DXA and pQCT predict pertrochanteric and not femoral neck fracture load in a human side-impact fracture model.

PubMed

Gebauer, Matthias; Stark, Olaf; Vettorazzi, Eik; Grifka, Joachim; Püschel, Klaus; Amling, Michael; Beckmann, Johannes

2014-01-01

The validity of dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) measurements as predictors of pertrochanteric and femoral neck fracture loads was compared in an experimental simulation of a fall on the greater trochanter. 65 proximal femora were harvested from patients at autopsy. All specimens were scanned with use of DXA for areal bone mineral density and pQCT for volumetric densities at selected sites of the proximal femur. A three-point bending test simulating a side-impact was performed to determine fracture load and resulted in 16 femoral neck and 49 pertrochanteric fractures. Regression analysis revealed that DXA BMD trochanter was the best variable at predicting fracture load of pertrochanteric fractures with an adjusted R(2) of 0.824 (p < 0.0001). There was no correlation between densitometric parameters and the fracture load of femoral neck fractures. A significant correlation further was found between body weight, height, femoral head diameter, and neck length on the one side and fracture load on the other side, irrespective of the fracture type. Clinically, the DXA BMD trochanter should be favored and integrated routinely as well as biometric and geometric parameters, particularly in elderly people with known osteoporosis at risk for falls. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Laboratory measurement of tip and global behavior for zero-toughness hydraulic fractures with circular and blade-shaped (PKN) geometry

NASA Astrophysics Data System (ADS)

Xing, Pengju; Yoshioka, Keita; Adachi, Jose; El-Fayoumi, Amr; Bunger, Andrew P.

2017-07-01

The tip behavior of hydraulic fractures is characterized by a rich nesting of asymptotic solutions, comprising a formidable challenge for the development of efficient and accurate numerical simulators. We present experimental validation of several theoretically-predicted asymptotic behaviors, namely for hydraulic fracture growth under conditions of negligible fracture toughness, with growth progressing from early-time radial geometry to large-time blade-like (PKN) geometry. Our experimental results demonstrate: 1) existence of a asymptotic solution of the form w ∼ s3/2 (LEFM) in the near tip region, where w is the crack opening and s is the distance from the crack tip, 2) transition to an asymptotic solution of the form w ∼ s2/3 away from the near-tip region, with the transition length scale also consistent with theory, 3) transition to an asymptotic solution of the form w ∼ s1/3 after the fracture attains blade-like (PKN) geometry, and 4) existence of a region near the tip of a blade-like (PKN) hydraulic fracture in which plane strain conditions persist, with the thickness of this region of the same order as the crack height.

Computerized method for detection of vertebral fractures on lateral chest radiographs based on morphometric data

NASA Astrophysics Data System (ADS)

Kasai, Satoshi; Li, Feng; Shiraishi, Junji; Li, Qiang; Straus, Christopher; Vokes, Tamara; MacMahon, Heber; Doi, Kunio

2007-03-01

Vertebral fractures are the most common osteoporosis-related fractures. It is important to detect vertebral fractures, because they are associated with increased risk of subsequent fractures, and because pharmacologic therapy can reduce the risk of subsequent fractures. Although vertebral fractures are often not clinically recognized, they can be visualized on lateral chest radiographs taken for other purposes. However, only 15-60% of vertebral fractures found on lateral chest radiographs are mentioned in radiology reports. The purpose of this study was to develop a computerized method for detection of vertebral fractures on lateral chest radiographs in order to assist radiologists' image interpretation. Our computerized method is based on the automated identification of upper and lower vertebral edges. In order to develop the scheme, radiologists provided morphometric data for each identifiable vertebra, which consisted of six points for each vertebra, for 25 normals and 20 cases with severe fractures. Anatomical information was obtained from morphometric data of normal cases in terms of vertebral heights, heights of vertebral disk spaces, and vertebral centerline. Computerized detection of vertebral fractures was based on the reduction in the heights of fractured vertebrae compared to adjacent vertebrae and normal reference data. Vertebral heights from morphometric data on normal cases were used as reference. On 138 chest radiographs (20 with fractures) the sensitivity of our method for detection of fracture cases was 95% (19/20) with 0.93 (110/118) false-positives per image. In conclusion, the computerized method would be useful for detection of potentially overlooked vertebral fractures on lateral chest radiographs.

[Long-term follow-up study of titanium implant impact on pediatric mandibular growth and development].

PubMed

Hu, Yun; Li, Wei; Chen, Qi; Song, Fumin; Tang, Wei; Wang, Hang

2015-08-01

To explore the impact of titanium implant on the growth and development of pediatric mandible after suffering from mandibular fracture and undergoing open reduction and internal fixation (ORIF) compared with those that underwent titanium plate removal postoperatively. Fifteen pediatric patients with mandibular fracture who underwent ORIF were included in this study. Eight patients did not undergo titanium implant removal postoperatively, whereas the other seven patients underwent the routine. The postoperative data of the pediatrics were collected for comparative analysis by taking the patients' frontal and lateral photos, recording the inter-incisor distance, and measuring the height of mandibular ramus, length of the mandibular body, and combined length of the mandible in three-dimensional reconstruction image. All patients had acceptable facial contour, mouth opening, and occlusion, without obvious abnormalities. The radiography showed no significant difference between the bilateral mandibular lengths in the two groups of patients (P>0.05). The titanium plants have no significant impact on the growth and development of pediatric mandible postoperatively; hence, the question on whether the titanium plates should be removed or not may be neglected. The removal operation may lead to secondary trauma; thus, performing titanium plate removal routinely is not recommended.

Comparison of clinical results between novel percutaneous pedicle screw and traditional open pedicle screw fixation for thoracolumbar fractures without neurological deficit.

PubMed

Yang, Ming; Zhao, Qinpeng; Hao, Dingjun; Chang, Zhen; Liu, Shichang; Yin, Xinhua

2018-06-16

To compare the efficacy and safety of novel percutaneous minimally invasive pedicle screw fixation and traditional open surgery for thoracolumbar fractures without neurological deficit. Sixty adult patients with single thoracolumbar fracture between June 2014 and June 2016 were recruited in this study, randomly divided into open fixation group (group A) or minimally invasive percutaneous fixation group (group B). Clinical and surgical evaluation including surgery time, blood losses, radiation times, hospital stay, and complication were performed. The two groups of patients with pre-operative and last follow-up anterior height ratio of fracture vertebral, Cobb angle of fracture vertebral, and VAS score of back pain were compared. All patients completed valid follow-ups, with an average time period of 15.4 months (12-26 months). Group B achieved much better results in time of operation, intra-operative blood loss, and length of stay than group A (P < 0.05). Group A was significantly better than group B in the times of radiation (P < 0.05). The VAS score was significantly lower in group B than in group A at three days after the operation (P < 0.05). There were no significant differences between the two groups in the anterior height ratio of fracture vertebral, Cobb angle, and VAS score in the last follow-up (P > 0.05). No injured nerve or other severe complications occurred in both groups; one of the patients from group A had back and loin pain lasting for about one month, which resolved after analgesia and functional training. There was no significant difference between the two groups in incidence of complications. Novel percutaneous pedicle screws with angle reset function can achieve the same effect as traditional open pedicle screw fixation in the treatment of thoracolumbar fractures without nerve injuries. Percutaneous minimally invasive pedicle screw fixation has the characteristics of shorter operative time, less bleeding, and less pain, but it needs more radiation times.

Deployment After Limb Salvage for High-Energy Lower-Extremity Trauma

DTIC Science & Technology

2012-01-01

idiopathic avascular necrosis of the talus, and one had an iatrogenic nerve injury after pelvic surgery. Six of the patients underwent circular external... avascular necrosis Unknown 10 40 Distal tibia fracture Fall from height 11 38 Calcaneus fracture, fifth metatarsal fracture, ankle fracture, talus...injury, and one fall from height). One patient developed idiopathic avascular ne- crosis of the talus without a precipitating injury, and one de

Prediction of incident hip fracture by femoral neck bone mineral density and neck-shaft angle: a 5-year longitudinal study in post-menopausal females.

PubMed

Gnudi, S; Sitta, E; Pignotti, E

2012-08-01

To compare hip fracture incidence in post-menopausal females who were differently stratified for the fracture risk according to bone mineral density and proximal femur geometry. In a 5 year follow-up study, the hip fracture incidence in 729 post-menopausal females (45 of whom suffered from incident hip fracture) was assessed and compared. Forward logistic regression was used to select independent predictors of hip fracture risk, including age, age at menopause, height, weight, femoral neck bone mineral density (FNBMD), neck-shaft angle (NSA), hip axis length, femoral neck diameter and femoral shaft diameter as covariates. Fracture incidence was then calculated for the categories of young/old age, high/low FNBMD and wide/narrow NSA, which were obtained by dichotomising each hip fracture independent predictor at the value best separating females with and without a hip fracture. The hip fracture incidence of the whole cohort was significantly higher in females with a wide NSA (8.52%) than in those with a narrow NSA (3.51%). The combination of wide NSA and low FNBMD had the highest hip fracture incidence in the whole cohort (17.61%) and each age category. The combinations of narrow/wide NSA with low/high FNBMD, respectively, gave a significantly higher fracture incidence in older than in younger women, whereas women with a combined wide NSA and low FNBMD had no significantly different fracture incidence in young (14.60%) or old age (21.62%). Our study showed that NSA is effective at predicting the hip fracture risk and that the detection in early post-menopause of a wide NSA together with a low FNBMD should identify females at high probability of incident hip fracture.

Prediction of incident hip fracture by femoral neck bone mineral density and neck–shaft angle: a 5-year longitudinal study in post-menopausal females

PubMed Central

Gnudi, S; Sitta, E; Pignotti, E

2012-01-01

Objective To compare hip fracture incidence in post-menopausal females who were differently stratified for the fracture risk according to bone mineral density and proximal femur geometry. Methods In a 5 year follow-up study, the hip fracture incidence in 729 post-menopausal females (45 of whom suffered from incident hip fracture) was assessed and compared. Forward logistic regression was used to select independent predictors of hip fracture risk, including age, age at menopause, height, weight, femoral neck bone mineral density (FNBMD), neck–shaft angle (NSA), hip axis length, femoral neck diameter and femoral shaft diameter as covariates. Fracture incidence was then calculated for the categories of young/old age, high/low FNBMD and wide/narrow NSA, which were obtained by dichotomising each hip fracture independent predictor at the value best separating females with and without a hip fracture. Results The hip fracture incidence of the whole cohort was significantly higher in females with a wide NSA (8.52%) than in those with a narrow NSA (3.51%). The combination of wide NSA and low FNBMD had the highest hip fracture incidence in the whole cohort (17.61%) and each age category. The combinations of narrow/wide NSA with low/high FNBMD, respectively, gave a significantly higher fracture incidence in older than in younger women, whereas women with a combined wide NSA and low FNBMD had no significantly different fracture incidence in young (14.60%) or old age (21.62%). Conclusion Our study showed that NSA is effective at predicting the hip fracture risk and that the detection in early post-menopause of a wide NSA together with a low FNBMD should identify females at high probability of incident hip fracture. PMID:22096224

Cyclic steaming in heavy oil diatomite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, M.; Beatty, F.D.

1995-12-31

Chevron currently uses cyclic steaming as a recovery method to produce economically its heavy oil diatomite resource in the Cymric field, San Joaquin Valley, California. A highly instrumented, cyclically steaming well from this field was simulated in this study to delineate important production mechanisms, to optimize operations, and to improve reservoir management. The model was constrained, as much as possible, by the available measured data. Results show that fluid flow from the well to the reservoir is primarily through the hydraulic fracture induced by the injected steam. Parameters with unique importance to modeling cyclic steaming in diatomites are: (1) inducedmore » fracture dimension (length and height), (2) matrix permeability, (3) oil/water capillary pressure, (4) grid size perpendicular to fracture face, and (5) producing bottomhole pressures. Additionally, parameters important for conventional steam injection processes, such as relative permeabilities and injected steam volume, quality, and rate, are important for diatomites also. Oil production rates and steam/oil ratios calculated by this model compare reasonably with field data.« less

Relationship of weight, height, and body mass index with fracture risk at different sites in postmenopausal women: the Global Longitudinal study of Osteoporosis in Women (GLOW).

PubMed

Compston, Juliet E; Flahive, Julie; Hosmer, David W; Watts, Nelson B; Siris, Ethel S; Silverman, Stuart; Saag, Kenneth G; Roux, Christian; Rossini, Maurizio; Pfeilschifter, Johannes; Nieves, Jeri W; Netelenbos, J Coen; March, Lyn; LaCroix, Andrea Z; Hooven, Frederick H; Greenspan, Susan L; Gehlbach, Stephen H; Díez-Pérez, Adolfo; Cooper, Cyrus; Chapurlat, Roland D; Boonen, Steven; Anderson, Frederick A; Adami, Silvano; Adachi, Jonathan D

2014-02-01

Low body mass index (BMI) is a well-established risk factor for fracture in postmenopausal women. Height and obesity have also been associated with increased fracture risk at some sites. We investigated the relationships of weight, BMI, and height with incident clinical fracture in a practice-based cohort of postmenopausal women participating in the Global Longitudinal study of Osteoporosis in Women (GLOW). Data were collected at baseline and at 1, 2, and 3 years. For hip, spine, wrist, pelvis, rib, upper arm/shoulder, clavicle, ankle, lower leg, and upper leg fractures, we modeled the time to incident self-reported fracture over a 3-year period using the Cox proportional hazards model and fitted the best linear or nonlinear models containing height, weight, and BMI. Of 52,939 women, 3628 (6.9%) reported an incident clinical fracture during the 3-year follow-up period. Linear BMI showed a significant inverse association with hip, clinical spine, and wrist fractures: adjusted hazard ratios (HRs) (95% confidence intervals [CIs]) per increase of 5 kg/m(2) were 0.80 (0.71-0.90), 0.83 (0.76-0.92), and 0.88 (0.83-0.94), respectively (all p < 0.001). For ankle fractures, linear weight showed a significant positive association: adjusted HR per 5-kg increase 1.05 (1.02-1.07) (p < 0.001). For upper arm/shoulder and clavicle fractures, only linear height was significantly associated: adjusted HRs per 10-cm increase were 0.85 (0.75-0.97) (p = 0.02) and 0.73 (0.57-0.92) (p = 0.009), respectively. For pelvic and rib fractures, the best models were for nonlinear BMI or weight (p = 0.05 and 0.03, respectively), with inverse associations at low BMI/body weight and positive associations at high values. These data demonstrate that the relationships between fracture and weight, BMI, and height are site-specific. The different associations may be mediated, at least in part, by effects on bone mineral density, bone structure and geometry, and patterns of falling. © 2014 American Society for Bone and Mineral Research.

Mechanical properties of kinked silicon nanowires

NASA Astrophysics Data System (ADS)

Jing, Yuhang; Zhang, Chuan; Liu, Yingzhi; Guo, Licheng; Meng, Qingyuan

2015-04-01

Molecular dynamics simulations are used to investigate the mechanical properties of KSiNWs. Our results show that KSiNWs have a much larger fracture strain compared to straight SiNWs. The effects of the periodic length of KSiNWs with symmetric arms and the arm length of the KSiNW with asymmetric arms on the mechanical properties of KSiNWs are studied. The fracture stress of KSiNWs decrease as the periodic length increases. However, the fracture strain of KSiNWs is not dependent on the short periodic length and the fracture strain of KSiNWs will abruptly increase to very large value and then vary slightly as the periodic length increases. In addition, the fracture stress is not dependent on arm length while the fracture strain monotonically increases as the arm length increases. We also investigate the fracture process of KSiNWs. The results in this paper suggest that the KSiNWs with larger fracture strain can be a promising anode materials in high performance Li-ion batteries.

[Operative treatment of displaced intra-articular calcaneal fractures].

PubMed

Zwipp, H; Rammelt, S; Amlang, M; Pompach, M; Dürr, C

2013-12-01

Anatomic reduction of displaced intra-articular calcaneal fractures with restoration of height, length, and axial alignment and reconstruction of the subtalar and calcaneocuboid joints. Displaced intra-articular calcaneal fractures with incongruity of the posterior facet of the subtalar joint, loss of height, and axial malalignment. High perioperative risk, soft tissue infection, advanced peripheral arterial disease (stage III), neurogenic osteoarthropathy, poor patient compliance (e. g., substance abuse). Extended lateral approach with the patient placed on the uninjured side. Reduction of the anatomic shape and joint surfaces according to the preoperative CT-based planning. Reduction of the medial wall and step-wise reconstruction of the posterior facet from medial to lateral. Reduction of the tuberosity and anterior process fragments to the posterior joint block and temporary fixation with Kirschner wires. Internal fixation with an anatomic lateral plate in a locking or nonlocking mode. Alternatively less invasive internal fixation with a calcaneus nail over a sinus tarsi approach for less severe fracture types. The lower leg is immobilized in a brace until the wound is healed. Range of motion exercises of the ankle and subtalar joints are initiated on the second postoperative day. Patients are mobilized in their own shoe with partial weight bearing of 20 kg for 6-12 weeks depending on fracture severity and bone quality. Over a 4-year period, 163 patients with 184 displaced, intra-articular calcaneal fractures were treated with a lateral plate via an extended approach. In all, 102 patients with 116 fractures were followed for a mean of 8 years. A surgical revision was necessary in 4 cases (3.4%) of postoperative hematoma, 2 (1.7%) superficial and 5 (4.3%) deep infections. Of the latter, 2 patients needed a free flap for definite wound coverage, no calcanectomy or amputation was needed. Secondary subtalar fusion for symptomatic posttraumatic arthritis was performed in 9 cases (7.8%). At follow-up, the AOFAS Ankle/Hindfoot Score averaged 70.2, the Zwipp Score averaged 76.0, the German versions of the Foot Function Index and SF-36 physical component averaged 32.8 and 42.2, respectively. Scores were significantly lower with increasing fracture severity according to the Sanders and Zwipp classifications, bilateral fractures, open fractures, and with work-related injuries. With less invasive fixation using a calcaneal nail, superficial wound edge necrosis was seen in 2 of 75 cases (2.7%).

Sacrificial bonds and hidden length in biomaterials: A kinetic constitutive description of strength and toughness in bone

NASA Astrophysics Data System (ADS)

Lieou, Charles K. C.; Elbanna, Ahmed E.; Carlson, Jean M.

2013-07-01

Sacrificial bonds and hidden length in structural molecules account for the greatly increased fracture toughness of biological materials compared to synthetic materials without such structural features by providing a molecular-scale mechanism for energy dissipation. One example is in the polymeric glue connection between collagen fibrils in animal bone. In this paper we propose a simple kinetic model that describes the breakage of sacrificial bonds and the release of hidden length, based on Bell's theory. We postulate a master equation governing the rates of bond breakage and formation. This enables us to predict the mechanical behavior of a quasi-one-dimensional ensemble of polymers at different stretching rates. We find that both the rupture peak heights and maximum stretching distance increase with the stretching rate. In addition, our theory naturally permits the possibility of self-healing in such biological structures.

The Corona Dentis: Description of an Anatomic Variant with Technical Implications for Anterior Odontoid Screw Placement.

PubMed

Alonso, Fernando; Iwanaga, Joe; Chapman, Jens R; Oskouian, Rod J; Tubbs, R Shane

2017-08-01

Type 2 odontoid fractures are the most common cervical fractures among the elderly. Neurologic deficit is usually caused by myelopathy as a result of posterior dens migration. Direct anterior screw placement provides stabilization and can preserve C1-C2 movement. The presence of a bony excrescence on the anterior superior tip of the dens may lead to placement of a screw of incorrect length. Twenty C2 dry specimens were examined for the presence of a corona dentis, which is a bony excrescence in the coronal plane near the apex of the dens. When identified, measurements of the corona dentis were performed using calipers and a ruler. In addition, anteroposterior (AP) and lateral fluoroscopy was performed on all specimens found to have a corona dentis. A corona dentis was found on 20% of our C2 specimens and had an average width of 9 mm and an average height of 4.5 mm. The average width of the dens did not vary as the normal tip of the dens transitioned into the coronae. In no specimen did the corona dentis seem to be composed of trabecular bone and it was seen as a superior projection of cortical bone on fluoroscopy. On fluoroscopy, the corona dentis could be identified on a true AP projection. In angulated AP views, fluoroscopic images overestimated the length of the corona dentis. We describe a new entity termed the corona dentis because of its crownlike feature. It is a superior cortical bone protrusion and should be noted as a variant of the dens during anterior odontoid screw placement. Its propensity to increase the height of the dens markedly can lead to higher rates of neurologic deficits during type 2 odontoid fractures if not appreciated. A true AP view is critical for correct screw size placement. Copyright © 2017 Elsevier Inc. All rights reserved.

Initiation and propagation of a PKN hydraulic fracture in permeable rock: Toughness dominated regime

NASA Astrophysics Data System (ADS)

Sarvaramini, E.; Garagash, D.

2011-12-01

The present work investigates the injection of a low-viscosity fluid into a pre-existing fracture with constrained height (PKN), as in waterflooding or supercritical CO2 injection. Contrary to conventional hydraulic fracturing, where 'cake build up' limits diffusion to a small zone, the low viscosity fluid allows for diffusion over a wider range of scales. Over large injection times the pattern becomes 2 or 3-D, necessitating a full-space diffusion modeling. In addition, the dissipation of energy associated with fracturing of rock dominates the energy needed for the low-viscosity fluid flow into the propagating crack. As a result, the fracture toughness is important in evaluating both the initiation and the ensuing propagation of these fractures. Classical PKN hydraulic fracturing model, amended to account for full-space leak-off and the toughness [Garagash, unpublished 2009], is used to evaluate the pressure history and fluid leak-off volume during the injection of low viscosity fluid into a pre-existing and initially stationary. In order to find the pressure history, the stationary crack is first subject to a step pressure increase. The response of the porous medium to the step pressure increase in terms of fluid leak-off volume provides the fundamental solution, which then can be used to find the transient pressurization using Duhamel theorem [Detournay & Cheng, IJSS 1991]. For the step pressure increase an integral equation technique is used to find the leak-off rate history. For small time the solution must converge to short time asymptote, which corresponds to 1-D diffusion pattern. However, as the diffusion length in the zone around the fracture increases the assumption of a 1-D pattern is no longer valid and the diffusion follows a 2-D pattern. The solution to the corresponding integral equation gives the leak-off rate history, which is used to find the cumulative leak-off volume. The transient pressurization solution is obtained using global conservation of fluid injected into the fracture. With increasing pressure in the fracture due to the fluid injection, the energy release rate eventually becomes equal to the toughness and fracture propagates. The evolution of the fracture length is established using the method similar to the one employed for the stationary crack.

Passive characterization of hydrofracture properties using signals from the hydraulic pumps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rector, J.W. III; Dong, Qichen

1995-12-31

In this study we utilize conical shear wave arrivals recorded in geophone observation wells to characterize a hydrofracture performed in the South Belridge Diatomite oil field. The conical wave arrivals are initially created by the hydraulic pumps on the surface, which send tube waves down the treatment borehole. Since the tube wave velocity in the Diatomite is greater than the shear formation velocity (the shear velocity in the diatomite is about 2,200 ft/s) cortical shear waves are radiated into the formation by the tube waves traveling down the treatment borehole. We use the decrease in amplitude of the tube wavemore » as it passes through the fracture zone to image changes in hydraulic conductivity of the fracture. By combining this information with estimates of the fracture height we obtain estimates of fracture width changes over time using the model of Tang and Cheng (1993). We find an excellent qualitative agreement between tube wave attenuation and pump pressure over time. Fracture widths estimated from the Tang and Cheng model appear to be consistent with the volume of injected fluid and the known length of the hydrofracture. Provided a monitor well can be instrumented, this technique holds potential for obtaining a relatively inexpensive real-time characterization of hydrofracs.« less

Fall from heights: does height really matter?

PubMed

Alizo, G; Sciarretta, J D; Gibson, S; Muertos, K; Romano, A; Davis, J; Pepe, A

2018-06-01

Fall from heights is high energy injuries and constitutes a fraction of all fall-related trauma evaluations while bearing an increase in morbidity and mortality. We hypothesize that despite advancements in trauma care, the overall survivability has not improved in this subset of trauma patients. All adult trauma patients treated after sustaining a fall from heights during a 40-month period were retrospectively reviewed. Admission demographics, clinical data, fall height (ft), injury patterns, ISS, GCS, length of stay, and mortality were reviewed. 116 patients sustained a fall from heights, 90.4% accidental. A mean age of 37± 14.7 years, 86% male, and a fall height of 19 ± 10 ft were encountered. Admission GCS was 13 ± 2 with ISS 10 ± 11. Overall LOS was 6.6 ± 14.9 days and an ICU LOS of 2.8 ± 8.9 days. Falls ≥ 25 ft.(16%) had lower GCS 10.4 ± 5.8, increased ISS 22.6 ± 13.8, a fall height 37.9 ± 13.1 ft and associated increased mortality (p < 0.001). Mortality was 5.2%, a mean distance fallen of 39 ± 22 ft. and an ISS of 31.5 ±16.5. Brain injury was the leading cause of death, 50% with open skull fractures. Level of height fallen is a good predictor of overall outcome and survival. Despite advances in trauma care, death rates remain unchanged. Safety awareness and injury prevention programs are needed to reduce the risk of high-level falls.

Femoral neck shaft angle width is associated with hip-fracture risk in males but not independently of femoral neck bone density.

PubMed

Ripamonti, C; Lisi, L; Avella, M

2014-05-01

To investigate the specificity of the neck shaft angle (NSA) to predict hip fracture in males. We consecutively studied 228 males without fracture and 38 with hip fracture. A further 49 males with spine fracture were studied to evaluate the specificity of NSA for hip-fracture prediction. Femoral neck (FN) bone mineral density (FN-BMD), NSA, hip axis length and FN diameter (FND) were measured in each subject by dual X-ray absorptiometry. Between-mean differences in the studied variables were tested by the unpaired t-test. The ability of NSA to predict hip fracture was tested by logistic regression. Compared with controls, FN-BMD (p < 0.01) was significantly lower in both groups of males with fractures, whereas FND (p < 0.01) and NSA (p = 0.05) were higher only in the hip-fracture group. A significant inverse correlation (p < 0.01) was found between NSA and FN-BMD. By age-, height- and weight-corrected logistic regression, none of the tested geometric parameters, separately considered from FN-BMD, entered the best model to predict spine fracture, whereas NSA (p < 0.03) predicted hip fracture together with age (p < 0.001). When forced into the regression, FN-BMD (p < 0.001) became the only fracture predictor to enter the best model to predict both fracture types. NSA is associated with hip-fracture risk in males but is not independent of FN-BMD. The lack of ability of NSA to predict hip fracture in males independent of FN-BMD should depend on its inverse correlation with FN-BMD by capturing, as the strongest fracture predictor, some of the effects of NSA on the hip fracture. Conversely, NSA in females does not correlate with FN-BMD but independently predicts hip fractures.

Femoral neck shaft angle width is associated with hip-fracture risk in males but not independently of femoral neck bone density

PubMed Central

Lisi, L; Avella, M

2014-01-01

Objective: To investigate the specificity of the neck shaft angle (NSA) to predict hip fracture in males. Methods: We consecutively studied 228 males without fracture and 38 with hip fracture. A further 49 males with spine fracture were studied to evaluate the specificity of NSA for hip-fracture prediction. Femoral neck (FN) bone mineral density (FN-BMD), NSA, hip axis length and FN diameter (FND) were measured in each subject by dual X-ray absorptiometry. Between-mean differences in the studied variables were tested by the unpaired t-test. The ability of NSA to predict hip fracture was tested by logistic regression. Results: Compared with controls, FN-BMD (p < 0.01) was significantly lower in both groups of males with fractures, whereas FND (p < 0.01) and NSA (p = 0.05) were higher only in the hip-fracture group. A significant inverse correlation (p < 0.01) was found between NSA and FN-BMD. By age-, height- and weight-corrected logistic regression, none of the tested geometric parameters, separately considered from FN-BMD, entered the best model to predict spine fracture, whereas NSA (p < 0.03) predicted hip fracture together with age (p < 0.001). When forced into the regression, FN-BMD (p < 0.001) became the only fracture predictor to enter the best model to predict both fracture types. Conclusion: NSA is associated with hip-fracture risk in males but is not independent of FN-BMD. Advances in knowledge: The lack of ability of NSA to predict hip fracture in males independent of FN-BMD should depend on its inverse correlation with FN-BMD by capturing, as the strongest fracture predictor, some of the effects of NSA on the hip fracture. Conversely, NSA in females does not correlate with FN-BMD but independently predicts hip fractures. PMID:24678889

Percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system: an analysis of 38 cases.

PubMed

Wang, Hong-wei; Li, Chang-qing; Zhou, Yue; Zhang, Zheng-feng; Wang, Jian; Chu, Tong-wei

2010-06-01

To prospectively evaluate the feasibility, safety and efficacy of the percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system in the retrospective non-randomized case-control study. A total of 38 consecutive non-randomized patients with type A thoracolumbar fractures, which had been stabilized posteriorly from December 2006 to March 2009, were examined retrospectively more than 9 months after surgery. Twenty-one patients had been treated conventionally with open pedicle screw fixation (OPSF) and 17 patients received minimally invasive treatment with Sextant percutaneous pedicle screw fixation (SPPSF). As a method of evaluation, the incision size, the intraoperation and postoperative volume of blood loss, operation time, postoperative hospital stay, blood transfusion, the radiological assessment of the sagittal Cobb;s angle, vertebral body angle and vertebral body height were recorded and compared. All patients were followed up for 8-24 months (average 11.6 months). There were significant differences in the incision size, surgical blood loss, surgical draining loss, operation time, hospital stay after operation, blood transfusion, the proportion of antalgic supplement and postoperative incisional VAS between the two groups (P less than 0.05). Mean preoperative kyphotic deformity was 16.0 degree and improved by 9.3 degree after surgery in OPSF group, but 15.2 degree and 10.3 degree respectively in SPPSF group. Mean preoperative angle of the fractured vertebral body was 15.9 degree and improved by 7.9 degree after surgery in OPSF group, but 14.9 degree and 6.6 degree respectively in SPPSF group. Mean anterior vertebral body height (% of normal) was 67.3% before surgery and 95.8% after surgery, but 69.1% and 90.1% respectively in SPPSF group. Mean posterior vertebral body height (% of normal) was 93.3% before surgery and 99.5% after surgery, but 88.9% and 93.3% respectively in SPPSF group. Among the patients whose 9-month follow-up films were available, 3.0 degree of kyphosis correction was lost in OPSF group, but 3.2 degree in SPPSF group. And 1.0 degree of the angle of the fractured vertebral body correction was lost in OPSF group, but 1.5 degree in SPPSF group. Then 3.0% of the anterior vertebral body height correction was lost in OPSF group, but 2.2% in SPPSF group. And 3.0% of the posterior vertebral body height correction was lost in OPSF group, but 2.5% in SPPSF group. The sagittal Cobb's angle, vertebral body angle and anterior height of the fractured vertebra were all significantly different in each group before and after operation (P less than 0.05). There were no significant differences in the postoperative sagittal Cobb's angle, vertebral body angle and the improvement of the vertebral body height and the kyphotic deformity correction between OPSF and SPPSF groups (P larger than 0.05), but there was significant difference in the postoperative anterior height of the fractured vertebra between the two groups (P less than 0.05). The percutaneous pedicle screw fixation through the pedicle of fractured vertebra using Sextant system is a good minimally-invasive surgical therapeutic choice for patients with type A thoracolumbar fracture except for that the SPPSF has a little insufficiency in resuming the anterior height of the fractured vertebra compared with OPSF.

Pontomedullary lacerations in falls from a height--a retrospective autopsy study.

PubMed

Zivković, Vladimir; Nikolić, Slobodan; Babić, Dragan; Djonić, Danijela; Atanasijević, Tatjana; Djurić, Marija

2012-05-01

Brainstem pontomedullary laceration (PML) in falls from a height appears as isolated cases and usually in feet-first impacts with a ring fracture. The aim of this study was to determine the frequency of PML in falls from a height, as well as the frequency of concomitant head and neck injuries. Out of 261 cases, PML was present in 40. An impact to the chin, as well as a feet- or buttocks-first impact, most often led to PML owing to transmission of the impact force. Also, a lateral, frontal, or posterior head impact, with subsequent hinge fracture, as well as the frontoposterior hyperextension of the head associated with an upper spine fracture, could be possible mechanisms of PML in falls from a height. The jawbone and other facial bones act as shock absorbers, and their fracture diminishes energy transfer toward the skull and protects the brain and brainstem from injury. © 2011 American Academy of Forensic Sciences.

Sacrificial bonds and hidden length in biomaterials -- a kinetic description of strength and toughness in bone

NASA Astrophysics Data System (ADS)

Lieou, Charles K. C.; Elbanna, Ahmed E.; Carlson, Jean M.

2013-03-01

Sacrificial bonds and hidden length in structural molecules account for the greatly increased fracture toughness of biological materials compared to synthetic materials without such structural features, by providing a molecular-scale mechanism of energy dissipation. One example of occurrence of sacrificial bonds and hidden length is in the polymeric glue connection between collagen fibrils in animal bone. In this talk, we propose a simple kinetic model that describes the breakage of sacrificial bonds and the revelation of hidden length, based on Bell's theory. We postulate a master equation governing the rates of bond breakage and formation, at the mean-field level, allowing for the number of bonds and hidden lengths to take up non-integer values between successive, discrete bond-breakage events. This enables us to predict the mechanical behavior of a quasi-one-dimensional ensemble of polymers at different stretching rates. We find that both the rupture peak heights and maximum stretching distance increase with the stretching rate. In addition, our theory naturally permits the possibility of self-healing in such biological structures.

Multi-scale Fracture Patterns Associated with a Complex Anticline Structure: Insights from Field Outcrop Analogues of the Jebel Hafit Pericline, Al Ain-UAE

NASA Astrophysics Data System (ADS)

Kokkalas, S.; Jones, R. R.; Long, J. J.; Zampos, M.; Wilkinson, M. W.; Gilment, S.

2017-12-01

The formation of folds and their associated fracture patterns plays an important role in controlling the migration and concentration of fluids within the upper crust. Prediction of fracture patterns from various fold shapes and kinematics still remains poorly understood in terms of spatial and temporal distribution of fracture sets. Thus, a more detailed field-based multi scale approach is required to better constrain 3D models of fold-fracture relationships, which are critical for reservoir characterization studies. In order to generate reservoir-scale fracture models representative fracture properties across a wider range of scales are needed. For this reason we applied modern geospatial technologies, including terrestrial LiDAR, photogrammetry and satellite images in the asymmetric, east verging, four-way closure Jebel Hafit anticline, in the eastern part of the United Arab Emirates. The excellent surface outcrops allowed the rapid acquisition of extensive areas of fracture data from both limbs and fold hinge area of the anticline, even from large areas of steep exposure that are practically inaccessible on foot. The digital outcrops provide longer 1D transects, and 2D or 3D surface datasets and give more robust data, particularly for fracture heights, lengths, spacing, clustering, termination and connectivity. The fracture patterns across the folded structure are more complex than those predicted from conceptual models and geomechanical fracture modeling. Mechanical layering, pre-existing structures and sedimentation during fold growth seem to exert a critical influence in the development of fracture systems within Jebel Hafit anticline and directly affect fracture orientations, spacing/intensity, segmentation and connectivity. Seismic and borehole data provide additional constraints on the sub-surface fold geometry and existence of large-scale thrusting in the core of the anticline. The complexity of the relationship between fold geometry and fracture intensity is presented and the implications for prediction of fracture networks in naturally fractured reservoirs are discussed.

Biomechanics of Thoracolumbar Burst and Chance-Type Fractures during Fall from Height

PubMed Central

Ivancic, Paul C.

2014-01-01

Study Design In vitro biomechanical study. Objective To investigate the biomechanics of thoracolumbar burst and Chance-type fractures during fall from height. Methods Our model consisted of a three-vertebra human thoracolumbar specimen (n = 4) stabilized with muscle force replication and mounted within an impact dummy. Each specimen was subjected to a single fall from an average height of 2.1 m with average velocity at impact of 6.4 m/s. Biomechanical responses were determined using impact load data combined with high-speed movie analyses. Injuries to the middle vertebra of each spinal segment were evaluated using imaging and dissection. Results Average peak compressive forces occurred within 10 milliseconds of impact and reached 40.3 kN at the ground, 7.1 kN at the lower vertebra, and 3.6 kN at the upper vertebra. Subsequently, average peak flexion (55.0 degrees) and tensile forces (0.7 kN upper vertebra, 0.3 kN lower vertebra) occurred between 43.0 and 60.0 milliseconds. The middle vertebra of all specimens sustained pedicle and endplate fractures with comminution, bursting, and reduced height of its vertebral body. Chance-type fractures were observed consisting of a horizontal split fracture through the laminae and pedicles extending anteriorly through the vertebral body. Conclusions We hypothesize that the compression fractures of the pedicles and vertebral body together with burst fracture occurred at the time of peak spinal compression, 10 milliseconds. Subsequently, the onset of Chance-type fracture occurred at 20 milliseconds through the already fractured and weakened pedicles and vertebral body due to flexion-distraction and a forward shifting spinal axis of rotation. PMID:25083357

Eyebrow ptosis after blowout fracture indicates impairment of trigeminal proprioceptive evocation that induces reflex contraction of the frontalis muscle.

PubMed

Ban, Ryokuya; Matsuo, Kiyoshi; Ban, Midori; Yuzuriha, Shunsuke

2013-01-01

The mixed levator and frontalis muscles lack the interior muscle spindles normally required to induce involuntary contraction of their slow-twitch fibers. To involuntarily move the eyelid and eyebrow, voluntary contraction of the levator nonskeletal fast-twitch muscle fibers stretches the mechanoreceptors in Müller's muscle to evoke trigeminal proprioception, which then induces reflex contraction of the levator and frontalis skeletal slow-twitch muscle fibers. The trigeminal proprioceptive nerve has a long intraorbital course from the mechanoreceptors in Müller's muscle to the superior orbital fissure. Since external force to the globe may cause impairment of trigeminal proprioceptive evocation, we confirmed how unilateral blowout fracture due to a hydraulic mechanism affects ipsilateral eyebrow movement as compared with unilateral zygomatic fracture. In 16 unilateral blowout fracture patients, eyebrow heights were measured on noninjured and injured sides in primary and 60° upward gaze and statistically compared. Eyebrow heights were also measured in primary gaze in 24 unilateral zygomatic fracture patients and statistically compared. In the blowout fracture patients, eyebrow heights on the injured side were significantly smaller than on the noninjured side in both gaze. In the zygomatic fracture patients, eyebrow heights on the injured side were significantly larger than on the noninjured side in primary gaze. Since 60° upward gaze did not recover the eyebrow ptosis observed in primary gaze in blowout fracture patients, such ptosis indicated impairment of trigeminal proprioceptive evocation and the presence of a hydraulic mechanism that may require ophthalmic examination.

Eyebrow Ptosis After Blowout Fracture Indicates Impairment of Trigeminal Proprioceptive Evocation That Induces Reflex Contraction of the Frontalis Muscle

PubMed Central

Ban, Ryokuya; Matsuo, Kiyoshi; Ban, Midori; Yuzuriha, Shunsuke

2013-01-01

Objective: The mixed levator and frontalis muscles lack the interior muscle spindles normally required to induce involuntary contraction of their slow-twitch fibers. To involuntarily move the eyelid and eyebrow, voluntary contraction of the levator nonskeletal fast-twitch muscle fibers stretches the mechanoreceptors in Müller's muscle to evoke trigeminal proprioception, which then induces reflex contraction of the levator and frontalis skeletal slow-twitch muscle fibers. The trigeminal proprioceptive nerve has a long intraorbital course from the mechanoreceptors in Müller's muscle to the superior orbital fissure. Since external force to the globe may cause impairment of trigeminal proprioceptive evocation, we confirmed how unilateral blowout fracture due to a hydraulic mechanism affects ipsilateral eyebrow movement as compared with unilateral zygomatic fracture. Methods: In 16 unilateral blowout fracture patients, eyebrow heights were measured on noninjured and injured sides in primary and 60° upward gaze and statistically compared. Eyebrow heights were also measured in primary gaze in 24 unilateral zygomatic fracture patients and statistically compared. Results: In the blowout fracture patients, eyebrow heights on the injured side were significantly smaller than on the noninjured side in both gaze. In the zygomatic fracture patients, eyebrow heights on the injured side were significantly larger than on the noninjured side in primary gaze. Conclusion: Since 60° upward gaze did not recover the eyebrow ptosis observed in primary gaze in blowout fracture patients, such ptosis indicated impairment of trigeminal proprioceptive evocation and the presence of a hydraulic mechanism that may require ophthalmic examination. PMID:23814636

Hydraulic fracturing in shales: the spark that created an oil and gas boom

NASA Astrophysics Data System (ADS)

Olson, J. E.

2017-12-01

In the oil and gas business, one of the valued properties of a shale was its lack of flow capacity (its sealing integrity) and its propensity to provide mechanical barriers to hydraulic fracture height growth when exploiting oil and gas bearing sandstones. The other important property was the high organic content that made shale a potential source rock for oil and gas, commodities which migrated elsewhere to be produced. Technological advancements in horizontal drilling and hydraulic fracturing have turned this perspective on its head, making shale (or other ultra-low permeability rocks that are described with this catch-all term) the most prized reservoir rock in US onshore operations. Field and laboratory results have changed our view of how hydraulic fracturing works, suggesting heterogeneities like bedding planes and natural fractures can cause significant complexity in hydraulic fracture growth, resulting in induced networks of fractures whose details are controlled by factors including in situ stress contrasts, ductility contrasts in the stratigraphy, the orientation and strength of pre-existing natural fractures, injection fluid viscosity, perforation cluster spacing and effective mechanical layer thickness. The stress shadowing and stress relief concepts that structural geologists have long used to explain joint spacing and orthogonal fracture pattern development in stratified sequences are key to understanding optimal injection point spacing and promotion of more uniform length development in induced hydraulic fractures. Also, fracture interaction criterion to interpret abutting vs crossing natural fracture relationships in natural fracture systems are key to modeling hydraulic fracture propagation within natural fractured reservoirs such as shale. Scaled physical experiments provide constraints on models where the physics is uncertain. Numerous interesting technical questions remain to be answered, and the field is particularly appealing in that better geologic understanding of the stratigraphic heterogeneity and material property attributes of shale can have a direct effect on the engineering design of wellbores and stimulation treatments.

Location of fractures and the characteristics of patients with atypical femoral fractures: analyses of 38 Japanese cases.

PubMed

Hyodo, Kojiro; Nishino, Tomofumi; Kamada, Hiroshi; Nozawa, Daisuke; Mishima, Hajime; Yamazaki, Masashi

2017-03-01

The purpose of this study was to determine fracture location and the characteristics of patients with atypical femoral fractures (AFFs). We studied 38 AFFs in 34 patients admitted to our institution between November 2007 and July 2013. The diagnostic criteria for the AFFs were based on 2014 American Society of Bone and Mineral Research guidelines. We classified the fracture location as proximal, middle, or distal to trisect the femoral diaphysis from just distal to the lesser trochanter to just proximal to the supracondylar flare. Bowing was defined as a line through the inside of the tip of the great trochanter and a condylar center that was outside the medullary cavity. We investigated the fracture's location, existence of coronal bowing, and bisphosphonates (BPs), glucocorticoids (GCs), and proton pump inhibitors therapy. We analyzed associations between fracture location and demographic and clinical factors. Twelve fractures were proximal, 25 were middle, and one was distal. Nineteen limbs showed femoral bowing. Thirty-one patients received BP treatment-20 patients received alendronic acid, eight risedronic acid, and three minodronic acid. Fourteen patients received a GC, and 16 received a proton pump inhibitor. There was a significant association between coronal bowing and middle fracture locations, GC therapy and proximal fracture locations, and older age and middle fracture locations. Tall height and heavy weight had an association with proximal fracture location, and short height and light weight had an association with middle fracture location. In conclusion, we provide evidence supporting a causal relationship between BP-related severely suppressed bone turnover and AFFs. We also provide evidence supporting additional influences from altered distribution of mechanical stress with femoral bowing and various factors, such as GC therapy, age, body weight, and height, which might negatively affect bone intensity and quality and result in fracture.

Influence of fracture extension on in-situ stress in tight reservoir

NASA Astrophysics Data System (ADS)

Zhang, Yongping; Wei, Xu; Zhang, Ye; Xing, Libo; Xu, Jianjun

2018-01-01

Currently, hydraulic fracturing is an important way to develop low permeability reservoirs. The fractures produced during the fracturing process are the main influencing factors of changing in-situ stress. In this paper, the influence of fracture extension on in-situ stress is studied by establishing a mathematical model to describe the relationship between fracture length and in-situ stress. The results show that the growth rate gradually decreases after the fracture reaches a certain length with the increase of fracturing time; the continuous extension of the fracture is the main factor to change the in-situ stress. In order to reduce the impact on the subsequent fracture extension due to the changing of in-situ stress, controlling fracturing time and fracture length without affecting the stimulated reservoir effect is an important way. The results presented in this study can effectively reduce the impact of changing of in-situ stress on subsequent fracturing construction.

Friction stir scribe welding technique for dissimilar joining of aluminium and galvanised steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Tianhao; Sidhar, Harpreet; Mishra, Rajiv S.

Friction stir scribe technology, a derivative of friction stir welding, was applied for the dissimilar lap welding of an aluminum alloy and galvanized mild steel sheets. During the process, the rotating tool with a cobalt steel scribe first penetrated the top material — aluminum — and then the scribe cut the bottom material — steel. The steel was displaced into the upper material to produce a characteristic hook feature. Lap welds were shear tested, and their fracture paths were studied. Welding parameters affected the welding features including hook height, which turned out to be highly related to fracture position. Therefore,more » in this paper, the relationships among welding parameters, hook height, joint strength and fracture position are presented. In addition, influence of zinc coating on joint strength was also studied. Keywords: friction stir scribe technology; dissimilar material welding; zinc coating; hook height; joint strength; fracture position« less

A descriptive study of accidental skeletal injuries and non-accidental skeletal injuries of child maltreatment.

PubMed

Ghanem, Maha A H; Moustafa, Tarek A; Megahed, Haidy M; Salama, Naglaa; Ghitani, Sara A

2018-02-01

Lack of awareness and recognition of child maltreatment is the major reason behind underreporting. All victims often interact with the health care system for routine or emergency care. In several research works, non-accidental fractures are the second most common injury in maltreated children and it is represented up to one-third of cases. To determine the incidence of different types of accidental and non-accidental skeletal injuries among children, estimate the severity of injuries according to the modified injury severity score and to determine the degree of fractures either closed or opened (Gustiloe-Anderson open fracture classification). Moreover, identifying fractures resulting from child abuse and neglect. This aimed for early recognition of non-accidental nature of fractures in child maltreatment that can prevent further morbidity and mortality. A descriptive study was carried out on all children (109) with skeletal injuries who were admitted to both Main Alexandria and El-Hadara Orthopedic and Traumatology University Hospitals during six months. History, physical examination and investigations were done for the patients. A detailed questionnaire was taken to diagnose child abuse and neglect. Gustiloe-Anderson open fracture classification was used to estimate the degree of open fractures. Out of 109 children, twelve cases (11%) were categorized as child maltreatment. One case was physical abuse, eight cases (7.3%) were child neglect and three cases (2.8%) were labour exploitation. Road traffic accidents (RTA) was the commonest cause of skeletal injuries followed by falling from height. Regarding falls, they included 4 cases of stair falls in neglected children and another four cases of falling from height (balcony/window). The remaining 36 cases of falls were accidental. The skeletal injuries were in the form of fractures in 99 cases, dislocation in two cases, both fracture and/or dislocation in three cases, and bone deformity from brachial plexus injury in five cases. Fractures of the lower limb (42.2%) and both bones of the forearm (35%) represented the highest incidence of skeletal injuries in children. 54.5% of fractures due to neglect were lower limb fractures due to falling from height. Ninety-nine cases were diagnosed as long bone fractures and classified as the following; eighty patients as closed fractures, six patients as open grade I fractures, three patients as open grade II fractures, three patients as open grade IIIA fractures, four patients as open grade IIIB fractures and three patients as open grade IIIC fractures. Cases of neglect and child abuse represented 11% of all the studied cases, where neglect was the main cause. RTA and falling from height represented the most common cause of skeletal injury in children. Most fractures due to neglect were lower limb fractures resulting from falling from height. This demonstrates the need for early detection of neglect and child maltreatment aiming for early initiation of parental educational programs about child care and safety. Misinterpretation of skeletal injuries due to neglect or abuse can be avoided by proper training of orthopedic and traumatology staff on signs of child neglect and abuse. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Traumatic Vertebral Fractures and Concomitant Fractures of the Rib in Southwest China, 2001 to 2010

PubMed Central

Wang, Hongwei; Zhou, Yue; Ou, Lan; Li, Changqing; Liu, Jun; Xiang, Liangbi

2015-01-01

Abstract To our knowledge, the clinical characteristics of traumatic vertebral fractures and concomitant fractures of the rib (TVF-RF) have not been described in previous studies. To investigate the clinical characteristics of patients managed for TVF-RF. A retrospective study of 3142 patients who presented with traumatic vertebral fractures was performed. Two hundred twenty-six patients (7.2%) suffered from TVF-RF. Incidence rate ratios were then calculated with respect to the level of injury to the spine, the ASIA classification of neurological deficits and age. There were 171 male (75.7%) and 55 female (24.3%) patients with a mean age of 43.8 years. The most common mechanisms were falls from high heights in 81 cases and road traffic crashes in 67 cases. Right-sided rib injury occurred in 106 cases, left-sided injury occurred in 76 cases, and bilateral injury occurred in 44 cases. The most frequent location of the rib fractures was from the fourth rib to the ninth rib (70.3%, 510/725). Initial pulmonary complications (IPC) after trauma occurred in 116 cases (51.3%). The mortality rate for the entire group was 1.3% (3/226). The patients with thoracic vertebral fractures and neurological deficits had a higher frequency of multiple rib fractures and IPC than the other patients (P < 0.05). With the increased number of rib fractures, the frequency of IPC and mean intensive care unit (ICU) length of stay also increased. The rates of complications for patients with rib fractures were significantly different from those without rib fractures. We should pay much attention to the patients who presented with thoracic vertebral fractures and neurological deficits for minimizing further complications and mortality in such patients who had a higher frequency of multiple rib fractures and IPC than the other patients. PMID:26554809

Pinedale unit MHF experiments. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1976-10-01

Three MHF experiments have been performed in a tight reservoir in the Northern Green River Basin at depths between 8,000 and 12,000 feet. A total of 894,190 gallons of fluid and 2,715,000 pounds of sand were pumped in three stages in two wells with the limited entry technique. Fluid viscosities were designed to give propped lengths of 1,000 to 1,500 feet and proppant sand beds having heights greater than 50 percent of the thickness of each sandstone fractured. The experiments included laboratory research to design limited entry with perforations through one and two strings of casing. Field data analysis tomore » determine fracture gradients and extent of perforation erosion has been complicated by a dependence of friction pressure in tubular goods upon sand concentration and by an apparent large variation in minimum principal in-situ stress between sandstones simultaneously fractured with the limited entry technique. A high proppant concentration was used to assure that production would be limited to reservoir characteristics, rather than fracture conductivity. Comparison was made with results of prior hydraulic fractures propped with a partial monolayer. Resulting production capacity to date has been only about one-fifth that projected in the National Gas Survey report. Evaluation of the resulting production capability and the cost of the hydraulic fracture treatmnet indicates that the stimulation technique employed is not commercially feasible at this time for the reservoir conditions tested. 10 fig, 6 tables.« less

Chronobiological Hypothesis about the Association Between Height Growth Seasonality and Geographical Differences in Body Height According to Effective Day Length

PubMed Central

Higuchi, Yukito

2016-01-01

Studies on growth hormone therapy in children have shown that height velocity is greater in summer than in winter and that this difference increases with latitude. It is hypothesized that summer daylight is a causative factor and that geographical distribution of body height will approximate the distribution of summer day length over time. This is an ecological analysis of prefecture-level data on the height of Japanese youth. Mesh climatic data of effective day length were collated. While height velocity was greatest during the summer, the height of Japanese youth was strongly and negatively correlated with the distribution of winter effective day length. Therefore, it is anticipated that summer height velocity is greater according to winter day length (dark period). This may be due to epigenetic modifications, involving reversible DNA methylation and thyroid hormone regulation found in the reproductive system of seasonal breeding vertebrates. If the function is applicable to humans, summer height growth may quantitatively increase with winter day length, and height growth seasonality can be explained by thyroid hormone activities that-induced by DNA methylation-change depending on the seasonal difference in day length. Moreover, geographical differences in body height may be caused by geographical differences in effective day length, which could influence melatonin secretion among subjects who spend a significant time indoors.

Influence of Turbulent Flow and Fractal Scaling on Effective Permeability of Fracture Network

NASA Astrophysics Data System (ADS)

Zhu, J.

2017-12-01

A new approach is developed to calculate hydraulic gradient dependent effective permeability of a fractal fracture network where both laminar and turbulent flows may occur in individual fractures. A critical fracture length is used to distinguish flow characteristics in individual fractures. The developed new solutions can be used for the case of a general scaling relationship, an extension to the linear scaling. We examine the impact on the effective permeability of the network of fractal fracture network characteristics, which include the fractal scaling coefficient and exponent, fractal dimension, ratio of minimum over maximum fracture lengths. Results demonstrate that the developed solution can explain more variations of the effective permeability in relation to the fractal dimensions estimated from the field observations. At high hydraulic gradient the effective permeability decreases with the fractal scaling exponent, but increases with the fractal scaling exponent at low gradient. The effective permeability increases with the scaling coefficient, fractal dimension, fracture length ratio and maximum fracture length.

Limits on the critical length of damage in weak snowpack layers from en-echelon slab fracture spacing observed during avalanche release

NASA Astrophysics Data System (ADS)

Gauthier, D.; Hutchinson, D. J.

2012-04-01

We present simple estimates of the maximum possible critical length of damage or fracture in a weak snowpack layer required to maintain the propagation that leads to avalanche release, based on observations of 'en-echelon' slab fractures during avalanche release. These slab fractures may be preserved in situ if the slab does not slide down slope. The en-echelon fractures are spaced evenly, normally with one every one to ten metres or more. We consider a simple two-dimensional model of a slab and weak layer, with upslope fracture propagating the weak layer, and examine the relationship between the weak layer and en-echelon slab fractures. We assume that the slab fracture occurs in tension, and initiates at either the base or surface of the slab in the area of peak tensile stress at the tip of the weak layer fracture. We also assume that if at the time the slab is completely bisected by fracture the propagation in the weak layer will arrest spontaneously if it has not advanced beyond the critical length. In this scenario, en-echelon slab fractures may only form when the weak layer fracture repeatedly exceeds the critical length; otherwise, there could be only a single slab fracture. We estimate the position of the weak layer fracture at the time of slab bisection using the slab thickness and ratio between the fracture speeds in the weak layer and slab. We show that in the simple model en-echelon fractures only form if the slab thickness multiplied by the velocity ratio is greater than the critical length. Of course, the critical length must also be less than the en-echelon spacing. It follows that the first relationship must be valid independent of the occurrence of en-echelon fractures, although the speed ratio may be process-dependent and difficult to estimate. We use this method to calculate maximum critical lengths for propagation in actual avalanches with and without en echelon fractures, and discuss the implications for comparing competing propagation models. Furthermore, we discuss the possible applications to other cases of progressive basal failure and en-echelon fracturing, e.g. the ribbed flow bowls or so-called 'thumbprint' morphology which sometimes develops during landsliding in sensitive clay soils.

Cubic law with aperture-length correlation: implications for network scale fluid flow

NASA Astrophysics Data System (ADS)

Klimczak, Christian; Schultz, Richard A.; Parashar, Rishi; Reeves, Donald M.

2010-06-01

Previous studies have computed and modeled fluid flow through fractured rock with the parallel plate approach where the volumetric flow per unit width normal to the direction of flow is proportional to the cubed aperture between the plates, referred to as the traditional cubic law. When combined with the square root relationship of displacement to length scaling of opening-mode fractures, total flow rates through natural opening-mode fractures are found to be proportional to apertures to the fifth power. This new relationship was explored by examining a suite of flow simulations through fracture networks using the discrete fracture network model (DFN). Flow was modeled through fracture networks with the same spatial distribution of fractures for both correlated and uncorrelated fracture length-to-aperture relationships. Results indicate that flow rates are significantly higher for correlated DFNs. Furthermore, the length-to-aperture relations lead to power-law distributions of network hydraulic conductivity which greatly influence equivalent permeability tensor values. These results confirm the importance of the correlated square root relationship of displacement to length scaling for total flow through natural opening-mode fractures and, hence, emphasize the role of these correlations for flow modeling.

Hydraulic Fracture Growth in a Layered Formation based on Fracturing Experiments and Discrete Element Modeling

NASA Astrophysics Data System (ADS)

Yushi, Zou; Xinfang, Ma; Tong, Zhou; Ning, Li; Ming, Chen; Sihai, Li; Yinuo, Zhang; Han, Li

2017-09-01

Hydraulic fracture (HF) height containment tends to occur in layered formations, and it significantly influences the entire HF geometry or the stimulated reservoir volume. This study aims to explore the influence of preexisting bedding planes (BPs) on the HF height growth in layered formations. Laboratory fracturing experiments were performed to confirm the occurrence of HF height containment in natural shale that contains multiple weak and high-permeability BPs under triaxial stresses. Numerical simulations were then conducted to further illustrate the manner in which vertical stress, BP permeability, BP density(or spacing), pump rate, and fluid viscosity control HF height growth using a 3D discrete element method-based fracturing model. In this model, the rock matrix was considered transversely isotropic and multiple BPs can be explicitly represented. Experimental and numerical results show that the vertically growing HF tends to be limited by multi-high-permeability BPs, even under higher vertical stress. When the vertically growing HF intersects with the multi-high-permeability BPs, the injection pressure will be sharply reduced. If a low pumping rate or a low-viscosity fluid is used, the excess fracturing fluid leak-off into the BPs obviously decreases the rate of pressure build up, which will then limit the growth of HF. Otherwise, a higher pumping rate and/or a higher viscosity will reduce the leak-off time and fluid volume, but increase the injection pressure to drive the HF to grow and to penetrate through the BPs.

Fragile external phenotype of modern human proximal femur in comparison with medieval bone.

PubMed

Sievänen, Harri; Józsa, László; Pap, Ildiko; Järvinen, Markku; Järvinen, Tero A; Kannus, Pekka; Järvinen, Teppo L

2007-04-01

Proximal femur macroanatomy of 118 medieval and 67 contemporary adults, 84 contemporary elderly, and 48 contemporary hip fracture cases was evaluated. Within approximately 1000 years, the femoral neck axis has become longer, and its cross-section has become proportionally smaller and more oval in shape. These changes in the present external phenotype alone account for approximately 50% higher fall-induced stress compared with the medieval situation. Bones, as whole skeletal structures, adapt to mechanical stresses they customarily experience. Because the present, mechanized lifestyle apparently deprives our skeletons of vigorous, habitual physical exertion, we studied whether the proximal femur phenotype has evolved vulnerable to fragility fractures by time. Proximal femur macroanatomy of 118 medieval and 67 contemporary adults, 84 contemporary elderly, and 48 contemporary hip fracture cases was evaluated. Using direct measurements of external bone dimensions and geometric properties, we estimated the fall-induced stress as an index of hip fragility. Within approximately 1000 years, the femoral axis length has become substantially longer (analysis of covariance, body height adjusted, p < 0.001), whereas the neck circumference has not increased. The macroanatomy was found similar between the contemporary adult and elderly groups. In hip fracture cases, however, the femoral axis length was further lengthened (p < 0.001), but the circumference was somewhat smaller (p = 0.001). Consequently, the estimated fall-induced stress can be approximately 1.5-fold today compared with the medieval times (p < 0.001), and the secular trend seemed to be worse in women (sex-time interaction, p = 0.001). The modern, relatively slender phenotype of the proximal femur alone seems to increase the fall-induced stress considerably, and when this phenotype coincides the osteoporotic, internally deteriorated femoral neck structure, fracture risk is imminent. This mechanically compromised external phenotype underscores the importance of timely strengthening of the skeleton and its regular maintenance throughout life.

Arm span and ulnar length are reliable and accurate estimates of recumbent length and height in a multiethnic population of infants and children under 6 years of age.

PubMed

Forman, Michele R; Zhu, Yeyi; Hernandez, Ladia M; Himes, John H; Dong, Yongquan; Danish, Robert K; James, Kyla E; Caulfield, Laura E; Kerver, Jean M; Arab, Lenore; Voss, Paula; Hale, Daniel E; Kanafani, Nadim; Hirschfeld, Steven

2014-09-01

Surrogate measures are needed when recumbent length or height is unobtainable or unreliable. Arm span has been used as a surrogate but is not feasible in children with shoulder or arm contractures. Ulnar length is not usually impaired by joint deformities, yet its utility as a surrogate has not been adequately studied. In this cross-sectional study, we aimed to examine the accuracy and reliability of ulnar length measured by different tools as a surrogate measure of recumbent length and height. Anthropometrics [recumbent length, height, arm span, and ulnar length by caliper (ULC), ruler (ULR), and grid (ULG)] were measured in 1479 healthy infants and children aged <6 y across 8 study centers in the United States. Multivariate mixed-effects linear regression models for recumbent length and height were developed by using ulnar length and arm span as surrogate measures. The agreement between the measured length or height and the predicted values by ULC, ULR, ULG, and arm span were examined by Bland-Altman plots. All 3 measures of ulnar length and arm span were highly correlated with length and height. The degree of precision of prediction equations for length by ULC, ULR, and ULG (R(2) = 0.95, 0.95, and 0.92, respectively) was comparable with that by arm span (R(2) = 0.97) using age, sex, and ethnicity as covariates; however, height prediction by ULC (R(2) = 0.87), ULR (R(2) = 0.85), and ULG (R(2) = 0.88) was less comparable with arm span (R(2) = 0.94). Our study demonstrates that arm span and ULC, ULR, or ULG can serve as accurate and reliable surrogate measures of recumbent length and height in healthy children; however, ULC, ULR, and ULG tend to slightly overestimate length and height in young infants and children. Further testing of ulnar length as a surrogate is warranted in physically impaired or nonambulatory children. © 2014 American Society for Nutrition.

Dimensional threshold for fracture linkage and hooking

NASA Astrophysics Data System (ADS)

Lamarche, Juliette; Chabani, Arezki; Gauthier, Bertrand D. M.

2018-03-01

Fracture connectivity in rocks depends on spatial properties of the pattern including length, abundance and orientation. When fractures form a single-strike set, they hardly cross-cut each other and the connectivity is limited. Linkage probability increases with increasing fracture abundance and length as small fractures connect to each other to form longer ones. A process for parallel fracture linkage is the "hooking", where two converging fracture tips mutually deviate and then converge to connect due to the interaction of their crack-tip stresses. Quantifying the processes and conditions for fracture linkage in single-strike fracture sets is crucial to better predicting fluid flow in Naturally Fractured Reservoirs. For 1734 fractures in Permian shales of the Lodève Basin, SE France, we measured geometrical parameters in 2D, characterizing three stages of the hooking process: underlapping, overlapping and linkage. We deciphered the threshold values, shape ratios and limiting conditions to switch from one stage to another one. The hook set up depends on the spacing (S) and fracture length (Lh) with the relation S ≈ 0.15 Lh. Once the hooking is initiated, with the fracture deviation length (L) L ≈ 0.4 Lh, the fractures reaches the linkage stage only when the spacing is reduced to S ≈ 0.02 Lh and the convergence (C) is < 0.1 L. These conditions apply to multi-scale fractures with a shape ratio L/S = 10 and for fracture curvature of 10°-20°.

Weight-for-length/height growth curves for children and adolescents in China in comparison with body mass index in prevalence estimates of malnutrition.

PubMed

Zong, Xinnan; Li, Hui; Zhang, Yaqin; Wu, Huahong

2017-05-01

It is important to update weight-for-length/height growth curves in China and re-examine their performance in screening malnutrition. To develop weight-for-length/height growth curves for Chinese children and adolescents. A total of 94 302 children aged 0-19 years with complete sex, age, weight and length/height data were obtained from two cross-sectional large-scaled national surveys in China. Weight-for-length/height growth curves were constructed using the LMS method before and after average spermarcheal/menarcheal ages, respectively. Screening performance in prevalence estimates of wasting, overweight and obesity was compared between weight-for-height and body mass index (BMI) criteria based on a test population of 21 416 children aged 3-18. The smoothed weight-for-length percentiles and Z-scores growth curves with length 46-110 cm for both sexes and weight-for-height with height 70-180 cm for boys and 70-170 cm for girls were established. The weight-for-height and BMI-for-age had strong correlation in screening wasting, overweight and obesity in each age-sex group. There was no striking difference in prevalence estimates of wasting, overweight and obesity between two indicators except for obesity prevalence at ages 6-11. This set of smoothed weight-for-length/height growth curves may be useful in assessing nutritional status from infants to post-pubertal adolescents.

Height, age at menarche and risk of hormone receptor-positive and -negative breast cancer: a cohort study.

PubMed

Ritte, Rebecca; Lukanova, Annekatrin; Tjønneland, Anne; Olsen, Anja; Overvad, Kim; Mesrine, Sylvie; Fagherazzi, Guy; Dossus, Laure; Teucher, Birgit; Steindorf, Karen; Boeing, Heiner; Aleksandrova, Krasimira; Trichopoulou, Antonia; Lagiou, Pagona; Trichopoulos, Dimitrios; Palli, Domenico; Grioni, Sara; Mattiello, Amalia; Tumino, Rosario; Sacerdote, Carlotta; Quirós, José Ramón; Buckland, Genevieve; Molina-Montes, Esther; Chirlaque, María-Dolores; Ardanaz, Eva; Amiano, Pilar; Bueno-de-Mesquita, Bas; van Duijnhoven, Franzel; van Gils, Carla H; Peeters, Petra Hm; Wareham, Nick; Khaw, Kay-Tee; Key, Timothy J; Travis, Ruth C; Krum-Hansen, Sanda; Gram, Inger Torhild; Lund, Eiliv; Sund, Malin; Andersson, Anne; Romieu, Isabelle; Rinaldi, Sabina; McCormack, Valerie; Riboli, Elio; Kaaks, Rudolf

2013-06-01

Associations of breast cancer overall with indicators of exposures during puberty are reasonably well characterized; however, uncertainty remains regarding the associations of height, leg length, sitting height and menarcheal age with hormone receptor-defined malignancies. Within the European Prospective Investigation into Cancer and Nutrition cohort, Cox proportional hazards models were used to describe the relationships of adult height, leg length and sitting height and age at menarche with risk of estrogen and progesterone receptor negative (ER-PR-) (n = 990) and ER+PR+ (n = 3,524) breast tumors. Height as a single risk factor was compared to a model combining leg length and sitting height. The possible interactions of height, leg length and sitting height with menarche were also analyzed. Risk of both ER-PR- and ER+PR+ malignancies was positively associated with standing height, leg length and sitting height and inversely associated with increasing age at menarche. For ER+PR+ disease, sitting height (hazard ratios: 1.14[95% confidence interval: 1.08-1.20]) had a stronger risk association than leg length (1.05[1.00-1.11]). In comparison, for ER-PR- disease, no distinct differences were observed between leg length and sitting height. Women who were tall and had an early menarche (≤13 years) showed an almost twofold increase in risk of ER+PR+ tumors but no such increase in risk was observed for ER-PR- disease. Indicators of exposures during rapid growth periods were associated with risks of both HR-defined breast cancers. Exposures during childhood promoting faster development may establish risk associations for both HR-positive and -negative malignancies. The stronger associations of the components of height with ER+PR+ tumors among older women suggest possible hormonal links that could be specific for postmenopausal women. Copyright © 2012 UICC.

Evaluation of hip fracture risk in relation to fall direction.

PubMed

Nankaku, Manabu; Kanzaki, Hideto; Tsuboyama, Tadao; Nakamura, Takashi

2005-11-01

The purpose of this study is to evaluate hip fracture risk in relation to fall direction, and to elucidate factors that influence the impact force in falls on the hip. Eight healthy volunteers performed deliberate falls in three directions (lateral, posterolateral and posterior) on a force platform covered by a mattress of 13 cm thickness. Fall descent motions and impact postures were examined by a three-dimensional analyzer. The maximum ground force reaction, velocity of the greater trochanter at impact, and activity of quadriceps and gluteus medius were measured. In all trials of lateral and posterolateral falls, but not of posterior falls, the subjects hit their greater trochanter directly on the mattress. The impact forces were between 2,000 N and 4,000 N. Posterolateral falls showed significantly higher velocity at impact than did posterior falls. The height and the lower limb length exhibited positive correlations with the impact force in all directions of fall. In the lateral fall, there was a positive correlation between the activity of quadriceps and the impact force. In view of the impact point, force, and velocity, the posterolateral fall seemed to carry the highest risk of hip fracture.

Best Stent Length Predicted by Simple CT Measurement Rather than Patient Height.

PubMed

Barrett, Keith; Foell, Kirsten; Lantz, Andrea; Ordon, Michael; Lee, Jason Y; Pace, Kenneth T; Honey, R John D'A

2016-09-01

Ureteral stent length is important, as stents that are too long might worsen symptoms and too short are at higher risk of migration. The purpose of this study was to determine if patient or radiologic parameters correlate with directly measured ureteral length and if directly measured ureteral length predicts proper stent positioning. During stent placement, ureteral length (ureteropelvic junction to ureterovesical junction distance) was directly measured by endoscopically viewing a ureteral catheter (with 1-cm marking) emanating from the ureteral orifice. A 22, 24, or 26 cm stent was chosen to be closest to the measured ureteral length. For ureters >26 cm, a 26 cm stent was chosen. Ends of an "ideally positioned" stent were fully curled in the renal pelvis and bladder, without crossing the bladder midline. Rates of ideal stent position were compared between patients with matching stent and ureteral lengths and those with stent lengths differing by ≥1 cm (mismatched). The measured ureteral length was correlated with patient height, L1-L5 height, and length measured on CT. Fifty-nine ureters from 57 patients were included. Height was reasonably correlated with L1-L5 height (Spearman correlation coefficient [rho] = 0.79), although both were poorly correlated with directly measured ureteral length (rho = 0.18 for height and 0.32 for lumbar height). Ureteral lengths measured on CT correlated well with direct measurement (rho = 0.63 for axial cuts and rho = 0.64 for coronal cuts). Matched stent length was associated with higher rates of ideal stent position than mismatched (100% vs 70.9%, p = 0.006). CT measurements, rather than height, correlate well with measured length and could be used to choose the appropriate stent length. Stents matching directly measured ureteral lengths are associated with high rates of ideal stent position.

Comparison of Wiltse's paraspinal approach and open book laminectomy for thoracolumbar burst fractures with greenstick lamina fractures: a randomized controlled trial.

PubMed

Chen, Zhi-da; Wu, Jin; Yao, Xiao-Tao; Cai, Tao-Yi; Zeng, Wen-Rong; Lin, Bin

2018-03-02

Posterior short-segment pedicle screw fixation is used to treat thoracolumbar burst fractures. However, no randomized controlled studies have compared the efficacy of the two approaches--the Wiltse's paraspinal approach and open book laminectomy in the treatment of thoracolumbar burst fractures with greenstick lamina fractures. Patients with burst fractures of the thoracolumbar spine without neurological deficit were randomized to receive either the Wiltse's paraspinal approach (group A, 24 patients) or open book laminectomy (group B, 23 patients). Patients were followed postoperatively for average of 27.4 months. Clinical and radiographic data of the two approaches were collected and compared. Our results showed the anterior segmental height, kyphotic angle, visual analog scale (VAS) score, and Smiley-Webster Scale (SWS) score significantly improved postoperatively in both groups, indicating that both the Wiltse's paraspinal approach and open book laminectomy can effectively treat thoracolumbar burst fractures with greenstick lamina fractures. The Wiltse's paraspinal approach was found to have significantly shorter operating time, less blood loss, and shorter length of hospital stay compared to open book laminectomy. However, there were two (2/24) patients in group A that had neurological deficits postoperatively and required a second exploratory operation. Dural tears and/or cauda equina entrapment were subsequently found in four patients in group B and all two patients of neurological deficits in group A during operation. No screw loosening, plate breakage, or other internal fixation failures were found at final follow-up. The results demonstrated that either of the two surgical approaches can achieve satisfactory results in treating thoracolumbar burst fractures in patients with greenstick lamina fractures. However, if there is any clinical or radiographic suspicion of a dural tear and/or cauda equina entrapment pre-operation, patients should receive an open book laminectomy to avoid a second exploratory operation. More research is still needed to optimize clinical decision-making regarding surgical approach.

Greater Polar Moment of Inertia at the Tibia in Athletes Who Develop Stress Fractures

PubMed Central

Weidauer, Lee A.; Binkley, Teresa; Vukovich, Matt; Specker, Bonny

2014-01-01

Background: Several previous investigations have determined potential risk factors for stress fractures in athletes and military personnel. Purpose: To determine factors associated with the development of stress fractures in female athletes. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 88 female athletes (cross-country, n = 29; soccer, n = 15; swimming, n = 9; track and field, n = 14; volleyball, n = 12; and basketball, n = 9) aged 18 to 24 years were recruited to participate in a longitudinal bone study and had their left distal tibia at the 4%, 20%, and 66% sites scanned by peripheral quantitative computed tomography (pQCT). Patients included 23 athletes who developed stress fractures during the following year (cases). Whole body, hip, and spine scans were obtained using dual-energy x-ray absorptiometry (DXA). Analysis of covariance was used to determine differences in bone parameters between cases and controls after adjusting for height, lower leg length, lean mass, fat mass, and sport. Results: No differences were observed between cases and controls in any of the DXA measurements. Cases had significantly greater unadjusted trabecular bone mineral content (BMC), greater polar moment of inertia (PMI) at the 20% site, and greater cortical BMC at the 66% site; however, after adjusting for covariates, the differences became nonsignificant. When analyses were repeated using all individuals who had ever had a stress fracture as cases (n = 31) and after controlling for covariates, periosteal circumference was greater in the cases than the controls (71.1 ± 0.7 vs 69.4 ± 0.5 mm, respectively; P = .04). Conclusion: A history of stress fractures is associated with larger bones. These findings are important because larger bones were previously reported to be protective against fractures and stress fractures, but study findings indicate that may not always be true. One explanation could be that individuals who sustain stress fractures have greater loading that results in greater periosteal circumference but also results in the development of stress fractures. PMID:26535343

Greater Polar Moment of Inertia at the Tibia in Athletes Who Develop Stress Fractures.

PubMed

Weidauer, Lee A; Binkley, Teresa; Vukovich, Matt; Specker, Bonny

2014-07-01

Several previous investigations have determined potential risk factors for stress fractures in athletes and military personnel. To determine factors associated with the development of stress fractures in female athletes. Case-control study; Level of evidence, 3. A total of 88 female athletes (cross-country, n = 29; soccer, n = 15; swimming, n = 9; track and field, n = 14; volleyball, n = 12; and basketball, n = 9) aged 18 to 24 years were recruited to participate in a longitudinal bone study and had their left distal tibia at the 4%, 20%, and 66% sites scanned by peripheral quantitative computed tomography (pQCT). Patients included 23 athletes who developed stress fractures during the following year (cases). Whole body, hip, and spine scans were obtained using dual-energy x-ray absorptiometry (DXA). Analysis of covariance was used to determine differences in bone parameters between cases and controls after adjusting for height, lower leg length, lean mass, fat mass, and sport. No differences were observed between cases and controls in any of the DXA measurements. Cases had significantly greater unadjusted trabecular bone mineral content (BMC), greater polar moment of inertia (PMI) at the 20% site, and greater cortical BMC at the 66% site; however, after adjusting for covariates, the differences became nonsignificant. When analyses were repeated using all individuals who had ever had a stress fracture as cases (n = 31) and after controlling for covariates, periosteal circumference was greater in the cases than the controls (71.1 ± 0.7 vs 69.4 ± 0.5 mm, respectively; P = .04). A history of stress fractures is associated with larger bones. These findings are important because larger bones were previously reported to be protective against fractures and stress fractures, but study findings indicate that may not always be true. One explanation could be that individuals who sustain stress fractures have greater loading that results in greater periosteal circumference but also results in the development of stress fractures.

Relationship between axial length of the emmetropic eye and the age, body height, and body weight of schoolchildren.

PubMed

Selović, Alen; Juresa, Vesna; Ivankovic, Davor; Malcic, Davor; Selović Bobonj, Gordana

2005-01-01

This report assesses the relationship of axial length of emmetropic (without refractive error) eyes to age, height, and weight in 1,600 Croatian schoolchildren. Axial eye lengths were determined by an ultrasonic eye biometry (A scan). Axial length of both eyes increases with age, height, and weight but shows a closer correlation to height and weight than to age. Boys have a significantly longer axial eye length than girls (P < 0.01). Boys or girls of similar or nearing body height and body weight and with emmetropic eyes have close linear measures of anatomic eye structures within their sex, regardless their age. Body height demonstrates the closest correlation to the growth and development of the emmetropic eye. Copyright 2005 Wiley-Liss, Inc.

Influence of Landscape Coverage on Measuring Spatial and Length Properties of Rock Fracture Networks: Insights from Numerical Simulation

NASA Astrophysics Data System (ADS)

Cao, Wenzhuo; Lei, Qinghua

2018-01-01

Natural fractures are ubiquitous in the Earth's crust and often deeply buried in the subsurface. Due to the difficulty in accessing to their three-dimensional structures, the study of fracture network geometry is usually achieved by sampling two-dimensional (2D) exposures at the Earth's surface through outcrop mapping or aerial photograph techniques. However, the measurement results can be considerably affected by the coverage of forests and other plant species over the exposed fracture patterns. We quantitatively study such effects using numerical simulation. We consider the scenario of nominally isotropic natural fracture systems and represent them using 2D discrete fracture network models governed by fractal and length scaling parameters. The groundcover is modelled as random patches superimposing onto the 2D fracture patterns. The effects of localisation and total coverage of landscape patches are further investigated. The fractal dimension and length exponent of the covered fracture networks are measured and compared with those of the original non-covered patterns. The results show that the measured length exponent increases with the reduced localisation and increased coverage of landscape patches, which is more evident for networks dominated by very large fractures (i.e. small underlying length exponent). However, the landscape coverage seems to have a minor impact on the fractal dimension measurement. The research findings of this paper have important implications for field survey and statistical analysis of geological systems.

A method to evaluate hydraulic fracture using proppant detection.

PubMed

Liu, Juntao; Zhang, Feng; Gardner, Robin P; Hou, Guojing; Zhang, Quanying; Li, Hu

2015-11-01

Accurate determination of the proppant placement and propped fracture height are important for evaluating and optimizing stimulation strategies. A technology using non-radioactive proppant and a pulsed neutron gamma energy spectra logging tool to determine the placement and height of propped fractures is proposed. Gd2O3 was incorporated into ceramic proppant and a Monte Carlo method was utilized to build the logging tools and formation models. Characteristic responses of the recorded information of different logging tools to fracture widths, proppant concentrations and influencing factors were studied. The results show that Gd capture gamma rays can be used to evaluate propped fractures and it has higher sensitivity to the change of fracture width and traceable proppant content compared with the exiting non-radioactive proppant evaluation techniques and only an after-fracture measurement is needed for the new method; The changes in gas saturation and borehole size have a great impact on determining propped fractures when compensated neutron and pulsed neutron capture tool are used. A field example is presented to validate the application of the new technique. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Chance fracture missed by convencional CT: Presentation of a clinical course].

PubMed

Pérez Suárez, Esther; Carceller, Fernando; García Salido, Alberto; Serrano, Ana; Casado, Juan

2011-02-01

Bending-disruption fractures of the vertebral body are called Chance fracture. In some cases these fractures may not be noticeable with a CT scan. A 9 years-old boy suffered a frontal collision while traveling in the back seat of a car. The child was secured by the safetybelt, without a child car seat or elevator adapted to his height. He had abdominal skin lesions in the physical exploration compatible with a belt mark. Conventional thoraco- abdominal CT scan did not show any vertebral fracture. As the clinical suspicion persisted, lateral plain radiography of the lumbar column was performed showing a Chance fracture in L2, confirmed by MRI. Chance fracture is typically seen in children under 12 years less than 135 cm height and with injuries associated with the belt after a traffic accident. This type of fractures may go unnoticed in a conventional CT scan so clinical suspicion must lead us to further work-up. The MRI is the gold standard for the diagnosis. This case remarks the importance of the use of homologated elevated seat devices in older children.

Impact of direct substitution of arm span length for current standing height in elderly COPD.

PubMed

Pothirat, Chaicharn; Chaiwong, Warawut; Phetsuk, Nittaya

2015-01-01

Arm span length is related to standing height and has been studied as a substitute for current standing height for predicting lung function parameters. However, it has never been studied in elderly COPD patients. To evaluate the accuracy of substituting arm span length for current standing height in the evaluation of pulmonary function parameters and severity classification in elderly Thai COPD patients. Current standing height and arm span length were measured in COPD patients aged >60 years. Postbronchodilator spirometric parameters, forced vital capacity (FVC), forced expiratory volume in first second (FEV1), and ratio of FEV1/FVC (FEV1%), were used to classify disease severity according to global initiative for chronic obstructive lung disease criteria. Predicted values for each parameter were also calculated separately utilizing current standing height or arm span length measurements. Student's t-tests and chi-squared tests were used to compare differences between the groups. Statistical significance was set at P<0.05. A total of 106 COPD patients with a mean age of 72.1±7.8 years, mean body mass index of 20.6±3.8 kg/m(2), and mean standing height of 156.4±8.3 cm were enrolled. The mean arm span length exceeded mean standing height by 7.7±4.6 cm (164.0±9.0 vs 156.4±8.3 cm, P<0.001), at a ratio of 1.05±0.03. Percentages of both predicted FVC and FEV1 values based on arm span length were significantly lower than those using current standing height (76.6±25.4 vs 61.6±16.8, P<0.001 and 50.8±25.4 vs 41.1±15.3, P<0.001). Disease severity increased in 39.6% (42/106) of subjects using arm span length over current standing height for predicted lung function. Direct substitution of arm span length for current standing height in elderly Thai COPD patients should not be recommended in cases where arm span length exceeds standing height by more than 4 cm.

Radiographic Outcomes of Volar Locked Plating for Distal Radius Fractures

PubMed Central

Mignemi, Megan E.; Byram, Ian R.; Wolfe, Carmen C.; Fan, Kang-Hsien; Koehler, Elizabeth A.; Block, John J.; Jordanov, Martin I.; Watson, Jeffry T.; Weikert, Douglas R.; Lee, Donald H.

2013-01-01

Purpose To assess the ability of volar locked plating to achieve and maintain normal radiographic parameters for articular stepoff, volar tilt, radial inclination, ulnar variance, and radial height in distal radius fractures. Methods We performed a retrospective review of 185 distal radius fractures that underwent volar locked plating with a single plate design over a 5-year period. We reviewed radiographs and recorded measurements for volar tilt, radial inclination, ulnar variance, radial height, and articular stepoff. We used logistic regression to determine the association between return to radiographic standard norms and fracture type. Results At the first and final postoperative follow-up visits, we observed articular congruence less than 2 mm in 92% of fractures at both times. Normal volar tilt (11°) was restored in 46% at the first follow-up and 48% at the final one. Radial inclination (22°) was achieved in 44% at the first follow-up and 43% at the final one, and ulnar variance (01 ± 2 mm) was achieved in 53% at the first follow-up and 53% at the final one. In addition, radial height (14 ± 1mm) was restored in 14% at the first follow-up and 12% at the final one. More complex, intra-articular fractures (AO class B and C and Frykman types 3, 4, 7, and 8) were less likely to be restored to normal radiographic parameters. However, because of the small sample size for some fracture types, it was difficult to discover significant associations between fracture type and radiographic outcome. Conclusions Volar locked plating for distal radius fractures achieved articular stepoff less than 2 mm in most fractures but only restored and maintained normal radiographic measurements for volar tilt, radial inclination, and ulnar variance in 50% of fractures. The ability of volar locked plating to restore and maintain ulnar variance and volar tilt decreased with more complex intra-articular fracture types. PMID:23218558

Clinical performance of a lithia disilicate-based core ceramic for three-unit posterior FPDs.

PubMed

Esquivel-Upshaw, Josephine F; Anusavice, Kenneth J; Young, Henry; Jones, Jack; Gibbs, Charles

2004-01-01

The purpose of this research project was to determine the clinical success rate of a lithia disilicate-based core ceramic for use in posterior fixed partial dentures (FPD) as a function of bite force, cement type, connector height, and connector width. Thirty ceramic FPD core frameworks were prepared using a heat-pressing technique and a lithia disilicate-based core ceramic. The maximum clenching force was measured for each patient prior to tooth preparation. Connector height and width were measured for each FPD. Patients were recalled yearly after cementation for 2 years and evaluated using 11 clinical criteria. All FPDs were examined by two independent clinicians, and rankings from 1 to 4 were made for each criterion (4 = excellent; 1 = unacceptable). Two of the 30 ceramic FPDs fractured within the 2-year evaluation period, representing a 93% success rate. One fracture was associated with a low occlusal force and short connector height (2.9 mm). The other fracture was associated with the greatest occlusal force (1,031 N) and adequate connector height. All criteria were ranked good to excellent during the 2-year recall for all remaining FPDs. The performance of the experimental core ceramic in posterior FPDs was promising, with only a 7% fracture rate after 2 years. Because of the limited sample size, it is not possible to identify the maximum clenching force that is allowable to prevent fracture caused by interocclusal forces.

Leg length, sitting height, and body proportions references for achondroplasia: New tools for monitoring growth.

PubMed

Del Pino, Mariana; Ramos Mejía, Rosario; Fano, Virginia

2018-04-01

Achondroplasia is the most common form of inherited disproportionate short stature. We report leg length, sitting height, and body proportion curves for achondroplasia. Seven centile format of sitting height, leg length, sitting height/leg length ratio, sitting height/height ratio, and head circumference/height ratio were estimated by the LMS method. The Q-test was applied to assess the goodness of fit. For comparison, centiles of sitting height and leg length were graphed using Argentine national growth references for achondroplasia and non-achondroplasia populations. The sample consisted of 342 children with achondroplasia (171 males, 171 females) aged 0-18 years. The median (interquartile range) number of measurements per child was 6 (3, 12) for sitting height and 8 (3, 13) for head circumference. Median leg length increased from 14 cm at age 1 week to 44 and 40 cm (males and females, respectively) in achondroplasia adolescents which is 3.5 cm shorter than non-achondroplasia children at age 1 week and, 38 cm shorter at adolescence. Median sitting height increased from 34 cm at birth to 86 and 81 in adolescents' boys and girls respectively, only 5 cm shorter than non-achondroplasia children. Sitting height/leg length decreased from 2.61 at birth to approximately 1.90 at adolescent. Median head circumference/height ratio decreased from 0.79 at birth to 0.46 at 18 years in both sexes. Growth of lower limbs is affected early in life and becomes more noticeable throughout childhood. The disharmonic growth between the less affected trunk and the severely affected limbs determine body disproportion in achondroplasia. © 2018 Wiley Periodicals, Inc.

Cephalometric features in isolated growth hormone deficiency.

PubMed

Oliveira-Neto, Luiz Alves; Melo, Mariade de Fátima B; Franco, Alexandre A; Oliveira, Alaíde H A; Souza, Anita H O; Valença, Eugênia H O; Britto, Isabela M P A; Salvatori, Roberto; Aguiar-Oliveira, Manuel H

2011-07-01

To analyze cephalometric features in adults with isolated growth hormone (GH) deficiency (IGHD). Nine adult IGHD individuals (7 males and 2 females; mean age, 37.8 ± 13.8 years) underwent a cross-sectional cephalometric study, including 9 linear and 5 angular measurements. Posterior facial height/anterior facial height and lower-anterior facial height/anterior facial height ratios were calculated. To pool cephalometric measurements in both genders, results were normalized by standard deviation scores (SDS), using the population means from an atlas of the normal Brazilian population. All linear measurements were reduced in IGHD subjects. Total maxillary length was the most reduced parameter (-6.5 ± 1.7), followed by a cluster of six measurements: posterior cranial base length (-4.9 ± 1.1), total mandibular length (-4.4 ± 0.7), total posterior facial height (-4.4 ± 1.1), total anterior facial height (-4.3 ± 0.9), mandibular corpus length (-4.2 ± 0.8), and anterior cranial base length (-4.1 ± 1.7). Less affected measurements were lower-anterior facial height (-2.7 ± 0.7) and mandibular ramus height (-2.5 ± 1.5). SDS angular measurements were in the normal range, except for increased gonial angle (+2.5 ± 1.1). Posterior facial height/anterior facial height and lower-anterior facial height/anterior facial height ratios were not different from those of the reference group. Congenital, untreated IGHD causes reduction of all linear measurements of craniofacial growth, particularly total maxillary length. Angular measurements and facial height ratios are less affected, suggesting that lGHD causes proportional blunting of craniofacial growth.

[A clinical study on the relationship of the tail femur distance and the lag screw migration or cutting-out after the third generation of Gamma nail fixation of intertrochanteric fracture].

PubMed

Hou, Yu; Yao, Qi; Zhang, Gen'ai; Ding, Lixiang

2018-01-01

To confirm the association between tail femur distance (TFD) and lag screw migration or cutting-out in the treatment of intertrochanteric fracture with the third generation of Gamma nail (TGN). The clinical data of 124 cases of intertrochanteric fracture treated with TGN internal fixation and followed up more than 18 months between January 2012 and December 2015 were reviewed and analyzed. There were 52 males and 72 females, with an age of 46-93 years (mean, 78.5 years). According to AO/Association for the Study of Internal Fixation (AO/ASIF) classification, 43 cases were type 31-A1, 69 cases were type 31-A2, and 12 cases were type 31-A3. The time from injury to operation was 1-10 days (mean, 2.9 days). According to the fracture healing of the patients, the patients were divided into the healing group and failure group. The age, gender, height, bone mineral density (BMD), fracture AO/ASIF classification, the time from injury to operation, and the TFD value at 1 day after operation were recorded and compared. The risk factors for the migration or cutting-out of lag screw were analyzed by logistic regression. There were 111 cases in healing group, the healing time was 80-110 days (mean, 95.5 days). There were 13 cases in failure group, including 2 cases of lag screw cutting-out and 11 cases of significant migration. Except for the TFD value at 1 day after operation in failure group was significantly higher than that in the healing group( t =5.14, P =0.00), there was no significant difference in gender, age, height, BMD, fracture of AO/ASIF classification, and the time from injury to operation ( P >0.05) between 2 groups. logistic regression analysis showed that TFD value was a risk factor for the migration or cutting-out of lag screw (B=1.22, standardized coefficient=0.32, Wald χ 2 =14.66, P =0.00, OR=3.37). The patients with higher TFD value had higher risk of postoperative lag screw migration or cutting-out. This result indicates that the appropriate length of the lag screw is helpful to reduce TFD value and prevent postoperative lag screw migration or cutting-out.

Breastfeeding protects against hip fracture in postmenopausal women: the Tromsø study.

PubMed

Bjørnerem, Ashild; Ahmed, Luai A; Jørgensen, Lone; Størmer, Jan; Joakimsen, Ragnar M

2011-12-01

Despite reported bone loss during pregnancy and lactation, no study has shown deleterious long-term effects of parity or breastfeeding. Studies have shown higher bone mineral density and reduced risk for fracture in parous than in nulliparous women or no effect of parity and breastfeeding, so long-term effects are uncertain. We studied the effect of parity and breastfeeding on risk for hip, wrist and non-vertebral fragility fractures (hip, wrist, or proximal humerus) in 4681 postmenopausal women aged 50 to 94 years in the Tromsø Study from 1994-95 to 2010, using Cox's proportional hazard models. During 51 906 person-years, and a median of 14.5 years follow-up, 442, 621, and 1105 of 4681 women suffered incident hip, wrist, and fragility fractures, and the fracture rates were 7.8, 11.4, and 21.3 per 1000 person-years, respectively. The risk for hip, wrist, and fragility fracture did not differ between parous (n = 4230, 90.4%) and nulliparous women (n = 451, 9.6%). Compared with women who did not breast-feed after birth (n = 184, 4.9%), those who breastfed (n = 3564, 95.1%) had 50% lower risk for hip fracture (HR 0.50; 95% CI 0.32 to 0.78), and 27% lower risk for fragility fracture (HR 0.73; 95% CI 0.54 to 0.99), but similar risk for wrist fracture, after adjustment for age, BMI, height, physical activity, smoking, a history of diabetes, previous fracture of hip or wrist, use of hormone replacement therapy, and length of education. Each 10 months longer total duration of breastfeeding reduced the age-adjusted risk for hip fracture by 12% (HR 0.88; 95% CI 0.78 to 0.99, p for trend = 0.03) before, and marginally after, adjustment for BMI and other covariates (HR 0.91; 95% CI 0.80 to 1.04). In conclusion, this data indicates that pregnancy and breastfeeding has no long-term deleterious effect on bone fragility and fractures, and that breastfeeding may contribute to a reduced risk for hip fracture after menopause. Copyright © 2011 American Society for Bone and Mineral Research.

Osteoporosis

MedlinePlus

... to restore the height of the vertebrae) Spinal fusion (bones of your spine are joined together so ... osteoporosis Patient Instructions Hip fracture - discharge Preventing falls Images Compression fracture Bone density scan Osteoporosis Osteoporosis Hip ...

Length-scale and strain rate-dependent mechanism of defect formation and fracture in carbon nanotubes under tensile loading

NASA Astrophysics Data System (ADS)

Javvaji, Brahmanandam; Raha, S.; Mahapatra, D. Roy

2017-02-01

Electromagnetic and thermo-mechanical forces play a major role in nanotube-based materials and devices. Under high-energy electron transport or high current densities, carbon nanotubes fail via sequential fracture. The failure sequence is governed by certain length scale and flow of current. We report a unified phenomenological model derived from molecular dynamic simulation data, which successfully captures the important physics of the complex failure process. Length-scale and strain rate-dependent defect nucleation, growth, and fracture in single-walled carbon nanotubes with diameters in the range of 0.47 to 2.03 nm and length which is about 6.17 to 26.45 nm are simulated. Nanotubes with long length and small diameter show brittle fracture, while those with short length and large diameter show transition from ductile to brittle fracture. In short nanotubes with small diameters, we observe several structural transitions like Stone-Wales defect initiation, its propagation to larger void nucleation, formation of multiple chains of atoms, conversion to monatomic chain of atoms, and finally complete fracture of the carbon nanotube. Hybridization state of carbon-carbon bonds near the end cap evolves, leading to the formation of monatomic chain in short nanotubes with small diameter. Transition from ductile to brittle fracture is also observed when strain rate exceeds a critical value. A generalized analytical model of failure is established, which correlates the defect energy during the formation of atomic chain with aspect ratio of the nanotube and strain rate. Variation in the mechanical properties such as elastic modulus, tensile strength, and fracture strain with the size and strain rate shows important implications in mitigating force fields and ways to enhance the life of electronic devices and nanomaterial conversion via fracture in manufacturing.

Clinical outcomes and hospital length of stay in 2,756 elderly patients with hip fractures: a comparison of surgical and non-surgical management.

PubMed

Tan, Stephen Thong Soon; Tan, Wei Ping Marcus; Jaipaul, Josephine; Chan, Siew Pang; Sathappan, Sathappan S

2017-05-01

The purpose of this study was to compare the clinical outcomes of elderly hip fracture patients who received surgical treatment with those who received non-surgical treatment. This retrospective study involved 2,756 elderly patients with hip fractures who were admitted over a six-year period. The patients' biodata, complications, ambulatory status at discharge and length of hospital stay were obtained from the institution's hip fracture registry. Among the 2,756 hip fracture patients, 2,029 (73.6%) underwent surgical intervention, while 727 (26.4%) opted for non-surgical intervention. The complication rate among the patients who underwent surgical intervention was 6.6%, while that among the patients who underwent non-surgical intervention was 12.5% (p < 0.01). The mean length of hospital stay for the surgical and non-surgical hip fracture patients was 15.7 days and 22.4 days, respectively (p < 0.01). Surgical management of hip fractures among the elderly is associated with a lower complication rate, as well as a reduced length of hospital stay. Copyright: © Singapore Medical Association

Effects of cane length and diameter and judgment type on the constant error ratio for estimated height in blindfolded, visually impaired, and sighted participants.

PubMed

Huang, Kuo-Chen; Leung, Cherng-Yee; Wang, Hsiu-Feng

2010-04-01

The purpose of this study was to assess the ability of blindfolded, visually impaired, and sighted individuals to estimate object height as a function of cane length, cane diameter, and judgment type. 48 undergraduate students (ages 20 to 23 years) were recruited to participate in the study. Participants were divided into low-vision, severely myopic, and normal-vision groups. Five stimulus heights were explored with three cane lengths, varying cane diameters, and judgment types. The participants were asked to estimate the stimulus height with or without reference to a standard block. Results showed that the constant error ratio for estimated height improved with decreasing cane length and comparative judgment. The findings were unclear regarding the effect of cane length on haptic perception of height. Implications were discussed for designing environments, such as stair heights, chairs, the magnitude of apertures, etc., for visually impaired individuals.

An analysis of fracture trace patterns in areas of flat-lying sedimentary rocks for the detection of buried geologic structure. [Kansas and Texas

NASA Technical Reports Server (NTRS)

Podwysocki, M. H.

1974-01-01

Two study areas in a cratonic platform underlain by flat-lying sedimentary rocks were analyzed to determine if a quantitative relationship exists between fracture trace patterns and their frequency distributions and subsurface structural closures which might contain petroleum. Fracture trace lengths and frequency (number of fracture traces per unit area) were analyzed by trend surface analysis and length frequency distributions also were compared to a standard Gaussian distribution. Composite rose diagrams of fracture traces were analyzed using a multivariate analysis method which grouped or clustered the rose diagrams and their respective areas on the basis of the behavior of the rays of the rose diagram. Analysis indicates that the lengths of fracture traces are log-normally distributed according to the mapping technique used. Fracture trace frequency appeared higher on the flanks of active structures and lower around passive reef structures. Fracture trace log-mean lengths were shorter over several types of structures, perhaps due to increased fracturing and subsequent erosion. Analysis of rose diagrams using a multivariate technique indicated lithology as the primary control for the lower grouping levels. Groupings at higher levels indicated that areas overlying active structures may be isolated from their neighbors by this technique while passive structures showed no differences which could be isolated.

Trauma of facial skeleton in children: An indian perspective.

PubMed

Karim, Tanweer; Khan, Arshad Hafeez; Ahmed, Syed Saeed

2010-06-01

Both children and adults are subject to similar types of injuries but fractures of facial bones in children are relatively uncommon. The aim of this study was to evaluate the epidemiology of facial bone fractures among children of <12 years, their management and outcome in an Indian city. This retrospective study included children of <12 years of age with facial bone fractures admitted over a span of 3 years. In order to compare our results we reviewed the existing literature related to pediatric facial bone fractures. A total of 45 children were admitted for facial bone fractures. Forty (89%) of them were above 5 years of age and male to female ratio was 2:1. About 53.33% of these injuries were because of fall from height. Mandible fracture was the most common facial bone fracture among admitted patients. Symphysis and para-symphysis was the commonest site of mandibular fractures, seen in 49% cases. Majority of these fractures were managed by Inter-maxillary fixation and inter-osseous wiring. Mini-plates were used for widely displaced compound fractures. For un-displaced fractures observation alone was sufficient. Mandible is the commonest facial bone fracture in children, more often caused by accidental fall from height. The high osteogenic potential of pediatric mandible allows non-surgical management to be successful in an increased proportion of younger patients.

Origins and nature of non-Fickian transport through fractures

NASA Astrophysics Data System (ADS)

Wang, L.; Cardenas, M. B.

2014-12-01

Non-Fickian transport occurs across all scales within fractured and porous geological media. Fundamental understanding and appropriate characterization of non-Fickian transport through fractures is critical for understanding and prediction of the fate of solutes and other scalars. We use both analytical and numerical modeling, including direct numerical simulation and particle tracking random walk, to investigate the origin of non-Fickian transport through both homogeneous and heterogeneous fractures. For the simple homogenous fracture case, i.e., parallel plates, we theoretically derived a formula for dynamic longitudinal dispersion (D) within Poiseuille flow. Using the closed-form expression for the theoretical D, we quantified the time (T) and length (L) scales separating preasymptotic and asymptotic dispersive transport, with T and L proportional to aperture (b) of parallel plates to second and fourth orders, respectively. As for heterogeneous fractures, the fracture roughness and correlation length are closely associated with the T and L, and thus indicate the origin for non-Fickian transport. Modeling solute transport through 2D rough-walled fractures with continuous time random walk with truncated power shows that the degree of deviation from Fickian transport is proportional to fracture roughness. The estimated L for 2D rough-walled fractures is significantly longer than that derived from the formula within Poiseuille flow with equivalent b. Moreover, we artificially generated normally distributed 3D fractures with fixed correlation length but different fracture dimensions. Solute transport through 3D fractures was modeled with a particle tracking random walk algorithm. We found that transport transitions from non-Fickian to Fickian with increasing fracture dimensions, where the estimated L for the studied 3D fractures is related to the correlation length.

3D Simulation of Multiple Simultaneous Hydraulic Fractures with Different Initial Lengths in Rock

NASA Astrophysics Data System (ADS)

Tang, X.; Rayudu, N. M.; Singh, G.

2017-12-01

Hydraulic fracturing is widely used technique for extracting shale gas. During this process, fractures with various initial lengths are induced in rock mass with hydraulic pressure. Understanding the mechanism of propagation and interaction between these induced hydraulic cracks is critical for optimizing the fracking process. In this work, numerical results are presented for investigating the effect of in-situ parameters and fluid properties on growth and interaction of multi simultaneous hydraulic fractures. A fully coupled 3D fracture simulator, TOUGH- GFEM is used for simulating the effect of different vital parameters, including in-situ stress, initial fracture length, fracture spacing, fluid viscosity and flow rate on induced hydraulic fractures growth. This TOUGH-GFEM simulator is based on 3D finite volume method (FVM) and partition of unity element method (PUM). Displacement correlation method (DCM) is used for calculating multi - mode (Mode I, II, III) stress intensity factors. Maximum principal stress criteria is used for crack propagation. Key words: hydraulic fracturing, TOUGH, partition of unity element method , displacement correlation method, 3D fracturing simulator

Influence of remaining coronal tooth structure on fracture resistance and failure mode of restored endodontically treated maxillary incisors.

PubMed

Santos Pantaleón, Domingo; Morrow, Brian R; Cagna, David R; Pameijer, Cornelis H; Garcia-Godoy, Franklin

2018-03-01

Limited information is available on the effect of an incomplete ferrule because of the varying residual axial wall heights and the volume of residual tooth structure on the fracture resistance of endodontically treated and restored maxillary incisors. The purpose of this in vitro investigation was to examine the effect of varying residual axial wall heights, residual coronal tooth structure, and the absence of 1 proximal axial wall on the fracture resistance and failure mode of endodontically treated teeth restored with metal posts. Sixty intact human maxillary central incisors were divided into 6 groups (n=10): no ferrule (NF), 2-mm complete ferrule (CF2), 2-mm (IF2), 3-mm (IF3), and 4-mm (IF4) incomplete ferrules missing a single interproximal wall, and a control group that had a 6-mm incomplete ferrule (IF6). Cast metal post-and-cores were placed in all experimental specimens except for controls. Control specimens received 1 interproximal cavity preparation extending to the root canal access and a composite resin restoration. Complete metal crowns were then cemented on all specimens. Completed specimens were subjected to thermocycling (6000 cycles, 5°C/55°C) followed by the immediate testing of fracture resistance. Failed specimens were sectioned buccolingually and evaluated to identify the failure mode. The data were analyzed with an analysis of variance (ANOVA) and the Student-Newman-Keuls multiple comparison test (α=.05). An incomplete ferrule (IF2) with 1 interproximal wall missing had significantly reduced fracture resistance (697 N) compared with a complete ferrule (932 N). An increase of 3 to 4 mm of remaining wall height improved fracture resistance, from 844 N (IF3) to 853 N (IF4). Partial decementation was noticed in 8 NF and 5 IF2 specimens. IF3 and IF4 had no decementations. Radicular fractures and cracks (catastrophic failure) were observed in all IF2, IF3, and IF4, 9 CF2, and 6 NF specimens. In 7 specimens without posts (IF6, control), composite resin foundation and/or coronal dentin fracture were observed and the failure was considered repairable. The results of this in vitro study indicated that specimens with a 2-mm ferrule of uniform height were more resistant to fracture than specimens with a 2-mm ferrule and 1 missing interproximal wall. An increased wall height of 3 or 4 mm was associated with a significant increase in fracture resistance and can compensate for the missing interproximal wall. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width groups

PubMed Central

Shahid, Fazal; Alam, Mohammad Khursheed; Khamis, Mohd Fadhli

2015-01-01

Objective: To investigate the maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width (intercanine, interpremolar, and intermolar) groups. Materials and Methods: The calculated sample size was 128 subjects. The crown width/height, arch length, arch perimeter, and arch width of the maxilla and mandible were obtained via digital calliper (Mitutoyo, Japan). A total of 4325 variables were measured. The sex differences in the crown width and height were evaluated. Analysis of variance was applied to evaluate the differences between arch length, arch perimeter, and arch width groups. Results: Males had significantly larger mean values for crown width and height than females (P ≤ 0.05) for maxillary and mandibular arches, both. There were no significant differences observed for the crown width/height ratio in various arch length, arch perimeter, and arch width (intercanine, interpremolar, and intermolar) groups (P ≤ 0.05) in maxilla and mandible, both. Conclusions: Our results indicate sexual disparities in the crown width and height. Crown width and height has no significant relation to various arch length, arch perimeter, and arch width groups of maxilla and mandible. Thus, it may be helpful for orthodontic and prosthodontic case investigations and comprehensive management. PMID:26929686

Implant Removal after Percutaneous Short Segment Fixation for Thoracolumbar Burst Fracture : Does It Preserve Motion?

PubMed Central

Kim, Hyeun Sung; Ju, Chang Il; Wang, Hui Sun; Lee, Sung Myung; Kim, Dong Min

2014-01-01

Objective The purpose of this study was to evaluate the efficacy of implant removal of percutaneous short segment fixation after vertebral fracture consolidation in terms of motion preservation. Methods Between May 2007 and January 2011, 44 patients underwent percutaneous short segment screw fixation due to a thoracolumbar burst fracture. Sixteen of these patients, who underwent implant removal 12 months after screw fixation, were enrolled in this study. Motor power was intact in all patients, despite significant vertebral height loss and canal compromise. The patients were divided into two groups by degree of osteoporosis : Group A (n=8), the non-osteoporotic group, and Group B (n=8), the osteoporotic group. Imaging and clinical findings including vertebral height loss, kyphotic angle, range of motion (ROM), and complications were analyzed. Results Significant pain relief was achieved in both groups at final follow-up versus preoperative values. In terms of vertebral height loss, both groups showed significant improvement at 12 months after screw fixation and restored vertebral height was maintained to final follow-up in spite of some correction loss. ROM (measured using Cobb's method) in flexion and extension in Group A was 10.5° (19.5/9.0°) at last follow-up, and in Group B was 10.2° (18.8/8.6°) at last follow-up. Both groups showed marked improvement in ROM as compared with the screw fixation state, which was considered motionless. Conclusion Removal of percutaneous implants after vertebral fracture consolidation can be an effective treatment to preserve motion regardless of osteoporosis for thoracolumbar burst fractures. PMID:24653799

[Is height restoration possible with a comparatively smaller amount of cement in radiofrequency kyphoplasty using a monopedicle approach?].

PubMed

Röllinghoff, M; Hagel, A; Siewe, J; Gutteck, N; Delank, K-S; Steinmetz, A; Zarghooni, K

2013-04-01

Percutaneous cement augmentation systems have been proven to be an effective treatment for vertebral compression fractures in the last 10 years. A special form available since 2009 is the radiofrequency kyphoplasty (RF) in which the applied energy raises the viscosity of the cement. The aim of this study is to find out if a smaller cement amount in radiofrequency kyphoplasty can also restore vertebral body height in osteoporotic vertebral compression fractures. The treatment was minimally invasive using the StabiliT® vertebral augmentation system by DFine. In a retrospective study from 2011 to January 2012, 35 patients underwent RF kyphoplasty for 49 fresh osteoporotic vertebral compression fractures. From the clinical side the parameters, demographics and pain relief using a visual analogue scale (VAS: 0 to 100 mm) were collected. For the radiological outcome the vertebral body height (anterior, mean and posterior vertebral body height with kyphosis angle) after surgery and after three months was measured and compared to the cement volume. All patients still had permanent pain on the fractured level after conservative treatment. The time from initial painful fracture to treatment was 3.0 weeks ± 1.3. Average visual analogue scale results decreased significantly from 71 ± 9.2 preoperatively to 35 ± 6.2 postoperatively (p < 0.001) and to 30 ± 5.7 (p < 0.001) after three months. With a mean cement volume in the thoracic spine of 2.9 ± 0.7 ml (1.8-4.1) and lumbar spine of 3.0 ± 0.7 ml (2.0-5.0) we had a significant vertebral body height restoration. Anterior and mean vertebral body heights significantly increased by an average of 2.3 and 3.1 mm, kyphosis angle significantly decreased with an average of 2.1° at three-month follow-up (p < 0.05). In two vertebrae (4.1 %) a minimal asymptomatic cement leakage occurred into the upper disc. In two patients (5.7 %) we had new fractures in the directly adjacent segment that were also successfully treated with radiofrequency kyphoplasty. With a mean cement volume of 3.0 ml radiofrequency kyphoplasty achieves rapid and short-term improvements of clinical symptoms with a significant restoration of vertebral body height. There was no correlation between restoration of vertebral body height and pain relief. With a cement leakage of 4.1 % RF kyphoplasty is a safe and effective minimally invasive percutaneous cement augmentation procedure. Our data confirm the higher safety described in literature for kyphoplasty in contrast to vertebroplasty. Georg Thieme Verlag KG Stuttgart · New York.

New approach to probability estimate of femoral neck fracture by fall (Slovak regression model).

PubMed

Wendlova, J

2009-01-01

3,216 Slovak women with primary or secondary osteoporosis or osteopenia, aged 20-89 years, were examined with the bone densitometer DXA (dual energy X-ray absorptiometry, GE, Prodigy - Primo), x = 58.9, 95% C.I. (58.42; 59.38). The values of the following variables for each patient were measured: FSI (femur strength index), T-score total hip left, alpha angle - left, theta angle - left, HAL (hip axis length) left, BMI (body mass index) was calculated from the height and weight of the patients. Regression model determined the following order of independent variables according to the intensity of their influence upon the occurrence of values of dependent FSI variable: 1. BMI, 2. theta angle, 3. T-score total hip, 4. alpha angle, 5. HAL. The regression model equation, calculated from the variables monitored in the study, enables a doctor in praxis to determine the probability magnitude (absolute risk) for the occurrence of pathological value of FSI (FSI < 1) in the femoral neck area, i. e., allows for probability estimate of a femoral neck fracture by fall for Slovak women. 1. The Slovak regression model differs from regression models, published until now, in chosen independent variables and a dependent variable, belonging to biomechanical variables, characterising the bone quality. 2. The Slovak regression model excludes the inaccuracies of other models, which are not able to define precisely the current and past clinical condition of tested patients (e.g., to define the length and dose of exposure to risk factors). 3. The Slovak regression model opens the way to a new method of estimating the probability (absolute risk) or the odds for a femoral neck fracture by fall, based upon the bone quality determination. 4. It is assumed that the development will proceed by improving the methods enabling to measure the bone quality, determining the probability of fracture by fall (Tab. 6, Fig. 3, Ref. 22). Full Text (Free, PDF) www.bmj.sk.

Modelling foot height and foot shape-related dimensions.

PubMed

Xiong, Shuping; Goonetilleke, Ravindra S; Witana, Channa P; Lee Au, Emily Yim

2008-08-01

The application of foot anthropometry to design good-fitting footwear has been difficult due to the lack of generalised models. This study seeks to model foot dimensions so that the characteristic shapes of feet, especially in the midfoot region, can be understood. Fifty Hong Kong Chinese adults (26 males and 24 females) participated in this study. Their foot lengths, foot widths, ball girths and foot heights were measured and then evaluated using mathematical models. The results showed that there were no significant allometry (p > 0.05) effects of foot length on ball girth and foot width. Foot height showed no direct relationship with foot length. However, a normalisation with respect to foot length and foot height resulted in a significant relationship for both males and females with R(2) greater than 0.97. Due to the lack of a direct relationship between foot height and foot length, the current practice of grading shoes with a constant increase in height or proportionate scaling in response to foot length is less than ideal. The results when validated with other populations can be a significant way forward in the design of footwear that has an improved fit in the height dimension.

Fractures in New Zealand Elementary School Settings

ERIC Educational Resources Information Center

Rubie-Davies, Christine M.; Townsend, Michael A. R.

2007-01-01

Background: There is a need for greater international understanding of student safety in schools. This New Zealand study investigated the causes and school location of fractures sustained by students attending elementary school, with special emphasis on the types of fractures sustained following falls from playground equipment of various heights.…

[Intramedullary nailing of the distal tibia illustrated with the Expert(TM) tibia nail].

PubMed

El Attal, R; Hansen, M; Rosenberger, R; Smekal, V; Rommens, P M; Blauth, M

2011-12-01

Restoration of axis, length, and rotation of the lower leg. Sufficient primary stability of the osteosynthesis for functional aftercare and to maintain joint mobility. Good bony healing in closed and open fractures. Closed and open fractures of the tibia and complete lower leg fractures distal to the isthmus (AO 42), extraarticular fractures of the distal tibia (AO 43 A1/A2/A3), segmental fractures of the tibia with a fracture in the distal tibia, and certain intraarticular fractures of the distal tibia without impression of the joint line with the use of additional implants (AO 43 C1) Patient in reduced general condition (e.g., bed ridden), flexion of the knee of less than 90°, patients with knee arthroplasty of the affected leg, infection in the area of the nail's insertion, infection of the tibial cavity, complex articular fractures of the proximal or distal tibia with joint depression. Closed reduction of the fracture preferably on a fracture table or using a distractor or an external fixation frame. If necessary, use pointed reduction clamps or sterile drapery. In some cases, additional implants like percutaneous small fragment screws, poller screws or k-wires are helpful. Open reduction is rarely necessary and must be avoided. Opening of the proximal tibia in line with the medullary canal. Canulated insertion of the Expert(TM) tibia nail (ETN; Synthes GmbH, Oberdorf, Switzerland) with reaming of the medullary canal. Control of axis, length, and rotation. Distal interlocking with the radiolucent drill and proximal interlocking with the targeting device. Immediate mobilization of ankle and knee joint. Mobilization with 20 kg weight-bearing with crutches. X-ray control 6 weeks postoperatively and increased weight-bearing depending on the fracture status. In cases with simple fractures, good bony contact, or transverse fracture pattern, full weight-bearing at the end of week 6 is targeted. Between July 2004 and May 2005, 180 patients were included in a multicenter study. The follow-up rate was 81% after 1 year. Of these, 91 fractures (50.6%) were located in the distal third of the tibia. In this segment, the rate of delayed union was 10.6%. Malalignment of > 5° was observed in 5.4%. A secondary malalignment after initial good reduction was detected in only 1.1% of all cases. The implant-specific risk for screw breakage was 3.2%. One patient sustained a deep infection. If additional fibula plating was performed an 8-fold higher risk for delayed bone healing was observed (95%CI: 2.9-21.2, p< 0.001). If the fracture of the fibula was at the same height as on the tibia, the risk for delayed healing was even 14-fold (95% CI: 3.4-62.5, p< 0.001). Biomechanically plating of the fibula does not increase stability in suprasyndesmal distal tibia-fibular fractures treated with an intramedullary nail. Using the ETN with its optimized locking options, fibula plating is not recommended, thus, avoiding soft tissue problems and potentially delayed bone healing.

Inclusion of Topological Measurements into Analytic Estimates of Effective Permeability in Fractured Media

NASA Astrophysics Data System (ADS)

Sævik, P. N.; Nixon, C. W.

2017-11-01

We demonstrate how topology-based measures of connectivity can be used to improve analytical estimates of effective permeability in 2-D fracture networks, which is one of the key parameters necessary for fluid flow simulations at the reservoir scale. Existing methods in this field usually compute fracture connectivity using the average fracture length. This approach is valid for ideally shaped, randomly distributed fractures, but is not immediately applicable to natural fracture networks. In particular, natural networks tend to be more connected than randomly positioned fractures of comparable lengths, since natural fractures often terminate in each other. The proposed topological connectivity measure is based on the number of intersections and fracture terminations per sampling area, which for statistically stationary networks can be obtained directly from limited outcrop exposures. To evaluate the method, numerical permeability upscaling was performed on a large number of synthetic and natural fracture networks, with varying topology and geometry. The proposed method was seen to provide much more reliable permeability estimates than the length-based approach, across a wide range of fracture patterns. We summarize our results in a single, explicit formula for the effective permeability.

Seismic Attenuation and Stiffness Modulus Dispersion in Porous Rocks Containing Stochastic Fracture Networks

NASA Astrophysics Data System (ADS)

Hunziker, Jürg; Favino, Marco; Caspari, Eva; Quintal, Beatriz; Rubino, J. Germán.; Krause, Rolf; Holliger, Klaus

2018-01-01

Understanding seismic attenuation and modulus dispersion mechanisms in fractured rocks can result in significant advances for the indirect characterization of such environments. In this paper, we study attenuation and modulus dispersion of seismic waves caused by fluid pressure diffusion (FPD) in stochastic 2-D fracture networks, allowing for a state-of-the-art representation of natural fracture networks by a power law length distribution. To this end, we apply numerical upscaling experiments consisting of compression and shear tests to our samples of fractured rocks. The resulting P and S wave attenuation and modulus dispersion behavior is analyzed with respect to the density, the length distribution, and the connectivity of the fractures. We focus our analysis on two manifestations of FPD arising in fractured rocks, namely, fracture-to-background FPD at lower frequencies and fracture-to-fracture FPD at higher frequencies. Our results indicate that FPD is sensitive not only to the fracture density but also to the geometrical characteristics of the fracture length distributions. In particular, our study suggests that information about the local connectivity of a fracture network could be retrieved from seismic data. Conversely, information about the global connectivity, which is directly linked to the effective hydraulic conductivity of the probed volume, remains rather difficult to infer.

In situ measurements of hydraulic fracture behavior, PTE-3. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.

Measurements of width and pressure in a propagating hydraulic fracture have been made in tests conducted at DOE`s Nevada Test Site. This was accomplished by creating an "instrumented fracture" at a tunnel complex (at a depth of 1400 ft) where realistic in situ conditions prevail, particularly with respect to stress and geologic features such as natural fractures and material anisotropy. Analyses of these data show that the pressure drop along the fracture length is much larger than predicted by viscous theory currently in use in models today. This is apparently due to the tortuosity of the fracture path, multiple fracturemore » strands, roughness, and sharp turns (corners) in the flow path due to natural fractures and rock property variations. It suggests that fracture design models need to be updated to include a more realistic friction factor so that fracture lengths are not overestimated. The width and pressure profiles near the crack tip have been investigated in some detail, including the length of the unwetted region and the tapering of the crack tip. The overall fracture behavior has been compared with published fracture models. Mineback of the fracture provided evidence of the geometry of the fracture and details of surface features. 35 refs., 89 figs., 30 tabs.« less

Risk factor analysis for predicting vertebral body re-collapse after posterior instrumented fusion in thoracolumbar burst fracture.

PubMed

Jang, Hae-Dong; Bang, Chungwon; Lee, Jae Chul; Soh, Jae-Wan; Choi, Sung-Woo; Cho, Hyeung-Kyu; Shin, Byung-Joon

2018-02-01

In the posterior instrumented fusion surgery for thoracolumbar (T-L) burst fracture, early postoperative re-collapse of well-reduced vertebral body fracture could induce critical complications such as correction loss, posttraumatic kyphosis, and metal failure, often leading to revision surgery. Furthermore, re-collapse is quite difficult to predict because of the variety of risk factors, and no widely accepted accurate prediction systems exist. Although load-sharing classification has been known to help to decide the need for additional anterior column support, this radiographic scoring system has several critical limitations. (1) To evaluate risk factors and predictors for postoperative re-collapse in T-L burst fractures. (2) Through the decision-making model, we aimed to predict re-collapse and prevent unnecessary additional anterior spinal surgery. Retrospective comparative study. Two-hundred and eight (104 men and 104 women) consecutive patients with T-L burst fracture who underwent posterior instrumented fusion were reviewed retrospectively. Burst fractures caused by high-energy trauma (fall from a height and motor vehicle accident) with a minimum 1-year follow-up were included. The average age at the time of surgery was 45.9 years (range, 15-79). With respect to the involved spinal level, 95 cases (45.6%) involved L1, 51 involved T12, 54 involved L2, and 8 involved T11. Mean fixation segments were 3.5 (range, 2-5). Pedicle screw instrumentation including fractured vertebra had been performed in 129 patients (62.3%). Clinical data using self-report measures (visual analog scale score), radiographic measurements (plain radiograph, computed tomography, and magnetic resonance image), and functional measures using the Oswestry Disability Index were evaluated. Body height loss of fractured vertebra, body wedge angle, and Cobb angle were measured in serial plain radiographs. We assigned patients to the re-collapse group if their body height loss progressed greater than 20% at any follow-up time compared with immediate postoperative body height loss; we assigned the remaining patients to the well-maintained group. The chi-square test and t test of SPSS were used for comparison of differences between two groups and multiple logistic regression analysis for risk factor evaluation. Through the decision tree analysis of statistical package R, a decision-making model was composed, and a cutoff value of revealed risk factors and re-collapse rate of each subgroup were identified. The present study wassupported by the University College of Medicine Research Fund (university to which authors belong). There was no external funding source for this study. The authors have no conflict of interest to declare. Re-collapse occurred in 31 of 208 patients (14.9%). In this group, age, the proportion of male gender, preoperative height loss, and preoperative wedge angle were significantly greater than the well-maintained group. Multivariable logistic regression analysis identified two independent risk factors: age (adjusted odds ratio 1.084, p=.002) and body height loss (adjusted odds ratio 1.065, p=.003). According to the decision-making tree, age (>43 years) was the most discriminating variable, andpreoperative body height loss (>54%) was the second. In this model, the re-collapse rate was zero in ages less than 43 years, and among those remaining, nearly 80% patients with greater than 54% of body height loss belonged to the re-collapse group. The independent predictors of re-collapse after posterior instrumented fusion for T-L burst fracture were the age at operation (>43 years old) and preoperative body height loss (>54%). Careful assessment using our decision-making model could help to predict re-collapse and prevent unnecessary additional spinal surgery for anterior column support, especially in young patients. Copyright © 2017 Elsevier Inc. All rights reserved.

A comparison of three different surgical procedures in the treatment of type A thoracolumbar fractures: a randomized controlled trial.

PubMed

Lyu, Jianhua; Chen, Kai; Tang, Zhaohui; Chen, Yu; Li, Ming; Zhang, Qiulin

2016-06-01

The aim of the study was to evaluate the efficacy of three different surgical procedures in the treatment of type A thoracolumbar fractures. Between September 2012 and January 2015, a total of 90 patients with type A thoracolumbar fractures were randomly assigned into three groups of 30 each. Patients in group A, B, and C were treated with three-level percutaneous fixation, two-level percutaneous fixation, and three-level open fixation, respectively. Blood loss, duration of surgery, VAS scores, Cobb angles, and anterior height ratios of fractured vertebrae were collected for statistical analysis. The average follow-up was 17.7 months. Post-operative Cobb angles were significantly corrected and anterior height ratios of fractured vertebrae were well restored in all three groups (p < 0.01). Back pain was efficiently relieved according to VAS score change (p < 0.01). There were significant differences in values of blood loss and post-operative VAS scores (at three months) between group A and group C (p < 0.01). No significant difference concerning post-operative anterior height ratios of fractured vertebrae, Cobb angles and correction losses was observed between group A and group B (p = 0.580, 0.840, 0.215, respectively). Percutaneous fixation not only provides the same reduction effect as open fixation, but also has an advantage of causing less operation related trauma which is beneficial to post-operative rehabilitation. The efficacy of three-level percutaneous fixation and two-level percutaneous fixation in the treatment of type A thoracolumbar fractures is not significantly different.

Falls from height: A retrospective analysis.

PubMed

Turgut, Kasim; Sarihan, Mehmet Ediz; Colak, Cemil; Güven, Taner; Gür, Ali; Gürbüz, Sükrü

2018-01-01

Emergency services manage trauma patients frequently and falls from height comprise the main cause of emergency service admissions. In this study, we aimed to analyse the demographic characteristics of falls from height and their relationship to the mortality. A total of 460 patients, who admitted to the Emergency Department of Inonu University between November 2011 and November 2014 with a history of fall from height, were examined retrospectively. Demographic parameters, fall characteristics and their effect to mortality were evaluated statistically. The study comprised of 292 (63.5%) men and 168 (36.5%) women patients. The mean age of all patients was 27±24.99 years. Twenty-six (5.6%) patients died and the majority of them were in ≥62 years old group. The highest percentage of falls was at 0-5 years age group (28.3%). People fell mainly from 1.1-4 metres(m) level (46.1%). The causes of falls were ordered as unintentional (92.2%), workplace (8.1%) and suicidal (1.7%). Skin and soft tissue injuries (37.4%) were the main traumatic lesions. Age, fall height, fall place, lineer skull fracture, subarachnoidal hemorrhage, cervical fracture, thoracic vertebra fracture and trauma scores had statistically significant effect on mortality. The casualties died because of subarachnoid hemorrhage mostly.

a Fractal Network Model for Fractured Porous Media

NASA Astrophysics Data System (ADS)

Xu, Peng; Li, Cuihong; Qiu, Shuxia; Sasmito, Agus Pulung

2016-04-01

The transport properties and mechanisms of fractured porous media are very important for oil and gas reservoir engineering, hydraulics, environmental science, chemical engineering, etc. In this paper, a fractal dual-porosity model is developed to estimate the equivalent hydraulic properties of fractured porous media, where a fractal tree-like network model is used to characterize the fracture system according to its fractal scaling laws and topological structures. The analytical expressions for the effective permeability of fracture system and fractured porous media, tortuosity, fracture density and fraction are derived. The proposed fractal model has been validated by comparisons with available experimental data and numerical simulation. It has been shown that fractal dimensions for fracture length and aperture have significant effect on the equivalent hydraulic properties of fractured porous media. The effective permeability of fracture system can be increased with the increase of fractal dimensions for fracture length and aperture, while it can be remarkably lowered by introducing tortuosity at large branching angle. Also, a scaling law between the fracture density and fractal dimension for fracture length has been found, where the scaling exponent depends on the fracture number. The present fractal dual-porosity model may shed light on the transport physics of fractured porous media and provide theoretical basis for oil and gas exploitation, underground water, nuclear waste disposal and geothermal energy extraction as well as chemical engineering, etc.

Bi-Pedicle Fixation of Affected Vertebra in Thoracolumbar Burst Fracture.

PubMed

Padalkar, Pravin; Mehta, Varshil

2017-04-01

Burst fractures of the spine account for 14% of all spinal injuries and more than 50% of all thoracolumbar trauma. However, there is ambiguity while choosing the right treatment plan. Short Segment Pedicle screw Fixation (SSPF) has become an increasingly popular method of treatment of thoracolumbar burst fractures, providing the advantage of incorporating fewer motion segments in the fixation. Various biomechanical studies showed that the use of pedicle screws could achieve stable construct within short-segment fixation. To evaluate the efficacy of SSPF using longest possible screws in both pedicles of fractured vertebra. A retrospective chart review of 25 single burst thoracolumbar fracture patients, operated between May 2009 to 2015 in a tertiary care trauma center, was conducted. Preoperative and post-operative plain radiographs were evaluated for kyphotic angulations using the traditional Cobb method. Anterior Vertebral Height (AVH), Posteriors Vertebral Height (PVH) were measured preoperatively and immediate postoperatively. Average percentage loss of AVH and mid-sagittal height were calculated on preoperative and postoperative X-rays on follow up. Fourteen men and 11 women with an average age of 42.92 years comprised the study population. Mean age at the time of operation was 34.5±14.2 years. Mean operation time was 168±72 (minutes). Average hospitalization time was 9±7 (days). Mean blood loss was 515±485 (ml). There were two cases of postoperative infection and implant failure each. A mean of 15.2° of kyphosis correction was attained from pre-operation to post-operation (p<0.0001). Although, there was a 15° average improvement of kyphosis post-fixation, loss of correction over time was nearly 8°, resulting in a 7° mean correction of kyphosis. A mean loss of AVH on postoperative radiograph was 6.12% and maintained 12.4% at the time of review (p<0.001). Similarly, there was 32.8% mid-sagittal height loss at time of injury, which was improved to only 12.6% as compare to initial height loss (p<0.0001). In this study, we propose SSPF using longest possible screws in both pedicle of fractured vertebra. Bi-pedicular fixation gives significant radiological corrections.

Fractures of the Tibial Plateau Involve Similar Energies as the Tibial Pilon but Greater Articular Surface Involvement

PubMed Central

Dibbern, Kevin; Kempton, Laurence B.; Higgins, Thomas F.; Morshed, Saam; McKinley, Todd O.; Marsh, J. Lawrence; Anderson, Donald D.

2016-01-01

Patients with tibial pilon fractures have a higher incidence of post-traumatic osteoarthritis than those with fractures of the tibial plateau. This may indicate that pilon fractures present a greater mechanical insult to the joint than do plateau fractures. We tested the hypothesis that fracture energy and articular fracture edge length, two independent indicators of severity, are higher in pilon than plateau fractures. We also evaluated if clinical fracture classification systems accurately reflect severity. Seventy-five tibial plateau fractures and fifty-two tibial pilon fractures from a multi-institutional study were selected to span the spectrum of severity. Fracture severity measures were calculated using objective CT-based image analysis methods. The ranges of fracture energies measured for tibial plateau and pilon fractures were 3.2 to 33.2 Joules (J) and 3.6 to 32.2 J, respectively, and articular fracture edge lengths were 68.0 to 493.0 mm and 56.1 to 288.6 mm, respectively. There were no differences in the fracture energies between the two fracture types, but plateau fractures had greater articular fracture edge lengths (p<0.001). The clinical fracture classifications generally reflected severity, but there was substantial overlap of fracture severity measures between different classes. Clinical Significance Similar fracture energies with different degrees of articular surface involvement suggest a possible explanation for dissimilar rates of post-traumatic osteoarthritis for fractures of the tibial plateau compared to the tibial pilon. The substantial overlap of severity measures between different fracture classes may well have confounded prior clinical studies relying on fracture classification as a surrogate for severity. PMID:27381653

Minimally invasive (sinus tarsi) approach for calcaneal fractures.

PubMed

Wang, Zhe; Wang, Xiu Hui; Li, Sheng Long; Tang, Xin; Fu, Bei Gang; Wang, Ming Hui; Xia, Sheng Li

2016-12-23

According to the anatomic characteristics of the calcaneus and the sinus tarsi approach, we designed a combined plate. The goal of this study was to retrospectively assess the functional outcomes and complications of treatment with our self-designed plate. From March 2014 to October 2015, 18 patients with closed calcaneal fractures (14 Sanders type II and 4 type III) were treated with our combined locking plate through a minimally invasive sinus tarsi approach. All patients underwent both clinical and radiological evaluations. The follow-up duration for all patients ranged from 6 to 13.5 months. The radiographs demonstrated significant corrections of the calcaneal width, length, height, Böhler angle, and Gissane angle from preoperatively to 3 months postoperatively and the last follow-up. However, there were no significant differences in the variables between 3 months postoperatively and the last follow-up. The mean Maryland foot score was 88.1 ± 8.8, in which excellent outcomes were achieved in 11 patients, good in 4, and fair in 3 (excellent and good rate, 83.3% (15 of 18)). No statistical significances in the mean Maryland foot score (88.1 ± 8.8 vs 87.8 ± 10.1, p = 0.9), and the excellent and good rate (85.7 vs 75.0%, p = 1.0) was found between type II and type III fractures. No complications were observed in all fractured feet. Treatment with our self-designed combined plate through a sinus tarsi approach may be safe and effective for type II and type III calcaneal fractures.

Cyclic fatigue of ProTaper instruments.

PubMed

Lopes, Hélio Pereira; Moreira, Edson Jorge Lima; Elias, Carlos Nelson; de Almeida, Renata Andriola; Neves, Mônica Schultz

2007-01-01

The present work evaluated the influence of the curved segment length of artificial root canals (the arc) and the number of cycles necessary to fracture engine-driven nickel-titanium endodontic instruments. ProTaper F3 25-mm files at 250 rpm were used in two artificial canals. The artificial canals were made of stainless steel with an inner diameter of 1.04 mm, a total length of 20 mm, and arc on the ends with a radius of curvature of 6 mm. The arc length of the first tube measured 9.4 mm, and the straight part measured 10.6 mm. The second tube was 14.1 mm long, and the straight part measured 5.9 mm. We determined the fracture surface distances and the number of cycles necessary to induce fatigue fracture in the ProTaper F3 instruments. The fracture surfaces and the helical shaft of the instruments were investigated using a scanning electron microscope. The results indicated that the required number of cycles to cause a fracture was influenced by the canal arc length, the morphology of the fractured surface presented ductile characteristics, and plastic deformation in the helical shaft of the fractured instruments did not occur.

Evaluation of a new approach to compute intervertebral disc height measurements from lateral radiographic views of the spine.

PubMed

Allaire, Brett T; DePaolis Kaluza, M Clara; Bruno, Alexander G; Samelson, Elizabeth J; Kiel, Douglas P; Anderson, Dennis E; Bouxsein, Mary L

2017-01-01

Current standard methods to quantify disc height, namely distortion compensated Roentgen analysis (DCRA), have been mostly utilized in the lumbar and cervical spine and have strict exclusion criteria. Specifically, discs adjacent to a vertebral fracture are excluded from measurement, thus limiting the use of DCRA in studies that include older populations with a high prevalence of vertebral fractures. Thus, we developed and tested a modified DCRA algorithm that does not depend on vertebral shape. Participants included 1186 men and women from the Framingham Heart Study Offspring and Third Generation Multidetector CT Study. Lateral CT scout images were used to place 6 morphometry points around each vertebra at 13 vertebral levels in each participant. Disc heights were calculated utilizing these morphometry points using DCRA methodology and our modified version of DCRA, which requires information from fewer morphometry points than the standard DCRA. Modified DCRA and standard DCRA measures of disc height are highly correlated, with concordance correlation coefficients above 0.999. Both measures demonstrate good inter- and intra-operator reproducibility. 13.9 % of available disc heights were not evaluable or excluded using the standard DCRA algorithm, while only 3.3 % of disc heights were not evaluable using our modified DCRA algorithm. Using our modified DCRA algorithm, it is not necessary to exclude vertebrae with fracture or other deformity from disc height measurements as in the standard DCRA. Modified DCRA also yields identical measurements to the standard DCRA. Thus, the use of modified DCRA for quantitative assessment of disc height will lead to less missing data without any loss of accuracy, making it a preferred alternative to the current standard methodology.

Axial and appendicular body proportions for evaluation of limb and trunk asymmetry.

PubMed

Weinberg, Douglas S; Liu, Raymond W; Li, Samuel Q; Sanders, James O; Cooperman, Daniel R

2017-04-01

Background and purpose - When children with irregular body proportions or asymmetric limbs present, it may be unclear where the pathology is located. An improved understanding of the clinical ratio between upper extremity, lower extremity, and spine length may help elucidate whether there is disproportion between the trunk and limbs, and whether there is a reduction deficit of the shorter limb rather than hypertrophy of the longer limb. Patients and methods - We used the Brush Foundation study of child growth and development, which was a prospective, longitudinal study of healthy children between the 1930s and the 1950s, and we collected serial clinical measurements for 290 children at 3,326 visits. Children ranged from 2 to 20 years of age during the study period. Linear and quadratic regression were used to construct nomographs and 95% prediction intervals for anthropometric body proportions. Results - The maximum anterior superior iliac spine height to sitting height ratio occurred at 12.4 years in females and at 14.17 years in males. Overall, the ratio of arm length to sitting height was 0.76 (SD 0.06), the ratio of arm length to anterior superior iliac spine height was 0.76 (SD 0.03), and the ratio of anterior superior iliac spine height to sitting height was 0.98 (SD 0.13). When comparing ratios between arm length, anterior superior iliac spine height, and sitting height, the smallest variance between appendicular proportions was found in the arm length to anterior superior iliac spine height ratio. Interpretation - We recommend comparisons between total arm length and anterior superior iliac spine height to distinguish limb reduction deficits from hemi-hypertrophy, with sitting height being used only if combined upper and lower extremity discrepancy is noted.

Axial and appendicular body proportions for evaluation of limb and trunk asymmetry

PubMed Central

Weinberg, Douglas S; Liu, Raymond W; Li, Samuel Q; Sanders, James O; Cooperman, Daniel R

2017-01-01

Background and purpose When children with irregular body proportions or asymmetric limbs present, it may be unclear where the pathology is located. An improved understanding of the clinical ratio between upper extremity, lower extremity, and spine length may help elucidate whether there is disproportion between the trunk and limbs, and whether there is a reduction deficit of the shorter limb rather than hypertrophy of the longer limb. Patients and methods We used the Brush Foundation study of child growth and development, which was a prospective, longitudinal study of healthy children between the 1930s and the 1950s, and we collected serial clinical measurements for 290 children at 3,326 visits. Children ranged from 2 to 20 years of age during the study period. Linear and quadratic regression were used to construct nomographs and 95% prediction intervals for anthropometric body proportions. Results The maximum anterior superior iliac spine height to sitting height ratio occurred at 12.4 years in females and at 14.17 years in males. Overall, the ratio of arm length to sitting height was 0.76 (SD 0.06), the ratio of arm length to anterior superior iliac spine height was 0.76 (SD 0.03), and the ratio of anterior superior iliac spine height to sitting height was 0.98 (SD 0.13). When comparing ratios between arm length, anterior superior iliac spine height, and sitting height, the smallest variance between appendicular proportions was found in the arm length to anterior superior iliac spine height ratio. Interpretation We recommend comparisons between total arm length and anterior superior iliac spine height to distinguish limb reduction deficits from hemi-hypertrophy, with sitting height being used only if combined upper and lower extremity discrepancy is noted. PMID:27998211

Stunting, adiposity, and the individual-level "dual burden" among urban lowland and rural highland Peruvian children.

PubMed

Pomeroy, Emma; Stock, Jay T; Stanojevic, Sanja; Miranda, J Jaime; Cole, Tim J; Wells, Jonathan C K

2014-01-01

The causes of the "dual burden" of stunting and obesity remain unclear, and its existence at the individual level varies between populations. We investigate whether the individual dual burden differentially affects low socioeconomic status Peruvian children from contrasting environments (urban lowlands and rural highlands), and whether tibia length can discount the possible autocorrelation between adiposity proxies and height due to height measurement error. Stature, tibia length, weight, and waist circumference were measured in children aged 3-8.5 years (n = 201). Height and body mass index (BMI) z scores were calculated using international reference data. Age-sex-specific centile curves were also calculated for height, BMI, and tibia length. Adiposity proxies (BMI z score, waist circumference-height ratio (WCHtR)) were regressed on height and also on tibia length z scores. Regression model interaction terms between site (highland vs. lowland) and height indicate that relationships between adiposity and linear growth measures differed significantly between samples (P < 0.001). Height was positively associated with BMI among urban lowland children, and more weakly with WCHtR. Among rural highland children, height was negatively associated with WCHtR but unrelated to BMI. Similar results using tibia length rather than stature indicate that stature measurement error was not a major concern. Lowland and rural highland children differ in their patterns of stunting, BMI, and WCHtR. These contrasts likely reflect environmental differences and overall environmental stress exposure. Tibia length or knee height can be used to assess the influence of measurement error in height on the relationship between stature and BMI or WCHtR. Copyright © 2014 Wiley Periodicals, Inc.

A Review of Computational Spinal Injury Biomechanics Research and Recommendations for Future Efforts

DTIC Science & Technology

2011-09-01

wedge vertebral fractures . The approximate degree of height reduction determines the assignment of grade to the fractured verte- bra (reproduced with...permission of Mary Ann Liebert, Inc.). (b) Lateral radiograph of lumbar spine shows a mild wedge fracture (grade 1) of L3 vertebra. (c) Lateral ra...diograph of lumbar spine shows moderate wedge fracture (grade 2) of L3 vertebra and moderate crush fracture (grade 2) of L2 vertebra. (d) Lateral

The effectiveness of a multidisciplinary hip fracture care model in improving the clinical outcome and the average cost of manpower.

PubMed

Lau, T W; Fang, C; Leung, F

2017-03-01

After the implementation of the multidisciplinary geriatric hip fracture clinical pathway in 2007, the hospital length of stay and the clinical outcomes improves. Moreover, the cost of manpower for each hip fracture decreases. It proves that this care model is cost-effective. The objective of this study is to compare the clinical outcomes and the cost of manpower before and after the implementation of the multidisciplinary geriatric hip fracture clinical pathway (GHFCP). The hip fracture data from 2006 was compared with the data of four consecutive years since 2008. The efficiency of the program is assessed using the hospital length of stay. The clinical outcomes include mortality rates and complication rates are compared. Cost of manpower was also analysed. After the implementation of the GHFCP, the preoperative length of stay shortened significantly from 5.8 days in 2006 to 1.3 days in 2011. The total length of stay in both acute and rehabilitation hospitals were also shortened by 6.1 days and 14.2 days, respectively. The postoperative pneumonia rate also decreased from 1.25 to 0.25%. The short- and long-term mortalities also showed a general improvement. Despite allied health manpower was increased to meet the increased workload, the shortened length of stay accounted for a mark decrease in cost of manpower per hip fracture case. This study proves that the GHFCP shortened the geriatric hip fracture patients' length of stay and improves the clinical outcomes. It is also cost-effective which proves better care is less costly.

Lower limb fracture presentations at a regional hospital.

PubMed

Holloway, K L; Yousif, D; Bucki-Smith, G; Hosking, S; Betson, A G; Williams, L J; Brennan-Olsen, S L; Kotowicz, M A; Sepetavc, A; Pasco, J A

2017-08-28

We found that lower limb fractures, which were largely the result of minimal trauma, had high levels of hospitalisation, length of stay and surgery. It is therefore important to prevent fractures at all sites to avoid the associated morbidity and mortality. Hip fractures are a major cause of morbidity and mortality, particularly in older women. In comparison, less is known about the epidemiology and burden of other lower limb fractures. The study aimed to investigate the epidemiology and burden of these fractures. Incident fractures of the hip, femur, tibia/fibula, ankle and foot in women (≥ 20 years) managed through the University Hospital Geelong, Australia, were ascertained from 1 Jan. 2014 to 31 Dec. 2014 from radiology reports. Age, cause of fracture, post-fracture hospitalisation, surgery, length of stay and discharge location were ascertained from medical records. We identified 585 fractures of the lower limb (209 hip, 42 femur, 41 tibia/fibula, 162 ankle, 131 foot). Most fractures were sustained by women aged ≥ 50 years. Fractures were largely a result of minimal trauma. Most women with hip or femur fractures were hospitalised; fewer were hospitalised for fractures at other sites. Surgery for fracture followed the same pattern as hospitalisations. Length of stay was the highest for hip and femur fractures and the lowest for foot fractures. Women with hip or femur fractures were discharged to rehabilitation more often than home. Fractures at other sites were most commonly discharged home. Fractures of the lower limb occurred frequently in older women. Hospitalisation and subsequent surgery were common in cases of hip and femur fractures. It is important for prevention strategies to target fractures at a range of skeletal sites to reduce costs, hospitalisations, loss of independence and reduced quality of life.

Computerized detection of vertebral compression fractures on lateral chest radiographs: Preliminary results with a tool for early detection of osteoporosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasai, Satoshi; Li Feng; Shiraishi, Junji

Vertebral fracture (or vertebral deformity) is a very common outcome of osteoporosis, which is one of the major public health concerns in the world. Early detection of vertebral fractures is important because timely pharmacologic intervention can reduce the risk of subsequent additional fractures. Chest radiographs are used routinely for detection of lung and heart diseases, and vertebral fractures can be visible on lateral chest radiographs. However, investigators noted that about 50% of vertebral fractures visible on lateral chest radiographs were underdiagnosed or under-reported, even when the fractures were severe. Therefore, our goal was to develop a computerized method for detectionmore » of vertebral fractures on lateral chest radiographs in order to assist radiologists' image interpretation and thus allow the early diagnosis of osteoporosis. The cases used in this study were 20 patients with severe vertebral fractures and 118 patients without fractures, as confirmed by the consensus of two radiologists. Radiologists identified the locations of fractured vertebrae, and they provided morphometric data on the vertebral shape for evaluation of the accuracy of detecting vertebral end plates by computer. In our computerized method, a curved search area, which included a number of vertebral end plates, was first extracted automatically, and was straightened so that vertebral end plates became oriented horizontally. Edge candidates were enhanced by use of a horizontal line-enhancement filter in the straightened image, and a multiple thresholding technique, followed by feature analysis, was used for identification of the vertebral end plates. The height of each vertebra was determined from locations of identified vertebral end plates, and fractured vertebrae were detected by comparison of the measured vertebral height with the expected height. The sensitivity of our computerized method for detection of fracture cases was 95% (19/20), with 1.03 (139/135) false-positive fractures per image. The accuracy of identifying vertebral end plates, marked by radiologists in a morphometric study, was 76.6% (400/522) and 70.9% (420/592) for cases used for training and those for testing, respectively. We prepared 32 additional fracture cases for a validation test, and we examined the detection accuracy of our computerized method. The sensitivity for these cases was 75% (24/32) at 1.03 (33/32) false-positive fractures per image. Our preliminary results show that the automated computerized scheme for detecting vertebral fractures on lateral chest radiographs has the potential to assist radiologists in detecting vertebral fractures.« less

Height restoration and maintenance after treating unstable osteoporotic vertebral compression fractures by cement augmentation is dependent on the cement volume used.

PubMed

Krüger, Antonio; Baroud, Gamal; Noriega, David; Figiel, Jens; Dorschel, Christine; Ruchholtz, Steffen; Oberkircher, Ludwig

2013-08-01

Two different procedures, used for percutaneous augmentation of vertebral compression fractures were compared, with respect to height restoration and maintenance after cyclic loading. Additionally the impact of the cement volume used was investigated. Wedge compression fractures were created in 36 human cadavaric vertebrae (T10-L3). Twenty-seven vertebrae were treated with the SpineJack® with different cement volumes (maximum, intermediate, and no cement), and 9 vertebrae were treated with Balloon Kyphoplasty. Vertebral heights were measured pre- and postfracture as well as after treatment and loading. Cyclic loading was performed with 10,000cycles (1Hz, 100-600N). The average anterior height after restoration was 85.56% for Kyphoplasty; 96.20% for SpineJack® no cement; 93.44% for SpineJack® maximum and 96% for the SpineJack® intermediate group. The average central height after restoration was 93.89% for Kyphoplasty; 100.20% for SpineJack® no cement; 99.56% for SpineJack® maximum and 101.13% for the SpineJack® intermediate group. The average anterior height after cyclic loading was 85.33 % for Kyphoplasty; 87.30% in the SpineJack® no cement, 92% in the SpineJack® maximum and 87% in the SpineJack® intermediate group. The average central height after cyclic loading was 92% for Kyphoplasty; 93.80% in the SpineJack® no cement; 98.56% in the SpineJack® maximum and 94.25% in the SpineJack® intermediate group. Height restoration was significantly better for the SpineJack® group compared to Kyphoplasty. Height maintenance was dependent on the cement volume used. The group with the SpineJack® without cement nevertheless showed better results in height maintenance, yet the statistical significance could not be demonstrated. Copyright © 2013 Elsevier Ltd. All rights reserved.

Deficits in heel-rise height and achilles tendon elongation occur in patients recovering from an Achilles tendon rupture.

PubMed

Silbernagel, Karin Grävare; Steele, Robert; Manal, Kurt

2012-07-01

Whether an Achilles tendon rupture is treated surgically or not, complications such as muscle weakness, decrease in heel-rise height, and gait abnormalities persist after injury. The purpose of this study was to evaluate if side-to-side differences in maximal heel-rise height can be explained by differences in Achilles tendon length. Case series; level of evidence, 4. Eight patients (mean [SD] age of 46 [13] years) with acute Achilles tendon rupture and 10 healthy subjects (mean [SD] age of 28 [8] years) were included in the study. Heel-rise height, Achilles tendon length, and patient-reported outcome were measured 3, 6, and 12 months after injury. Achilles tendon length was evaluated using motion analysis and ultrasound imaging. The Achilles tendon length test-retest reliability (intraclass correlation coefficient = 0.97) was excellent. For the healthy subjects, there were no side-to-side differences in tendon length and heel-rise height. Patients with Achilles tendon ruptures had significant differences between the injured and uninjured side for both tendon length (mean [SD] difference, 2.6-3.1 [1.2-1.4] cm, P = .017-.028) and heel-rise height (mean [SD] difference, -4.1 to -6.1 [1.7-1.8] cm, P = .012-.028). There were significant negative correlations (r = -0.943, P = .002, and r = -0.738, P = .037) between the side-to-side difference in heel-rise height and Achilles tendon length at the 6- and 12-month evaluations, respectively. The side-to-side difference found in maximal heel-rise height can be explained by a difference in Achilles tendon length in patients recovering from an Achilles tendon rupture. Minimizing tendon elongation appears to be an important treatment goal when aiming for full return of function.

Epidemiology of Surgically Managed Mandibular Condylar Fractures at a Tertiary Referral Hospital in Urban Southwest China.

PubMed

Thapa, Swosti; Wang, Jun; Hu, Hong-Tao; Zhang, Fu-Gui; Ji, Ping

2017-01-01

Mandibular condylar fracture is one of the commonest maxillofacial fractures treated by maxillofacial surgeons. Demography of the patients, causation, and characteristics of the fracture depends on various socio-economic factors. Hence, maxillofacial surgeons should be familiar with epidemiology of mandibular condylar fracture. This study retrospectively describes the demography, etiology, fracture characteristics, and hospital utilization of surgically treated mandibular condylar fractures in a tertiary referral hospital in urban China in past five years. Data of all patients who underwent surgical management between 2011 and 2015 were collected. This included aetiology, characteristics of fracture, time, age, sex, associated injuries, and hospital utilization of 166 patients with 208 mandibular condylar fractures. These patients had undergone open reduction and internal fixation with either miniplates or lag screws. Among the fracture of head of mandibular condyle, 21.28% of the patients had the fracture segments removed. These data were statistically analyzed to describe the epidemiology of mandibular condylar fracture. Most of the patients had unilateral mandibular condylar fractures (74.7%). Male patients (76.51%) outnumbered female patients (23.49%) in this cohort. The average age of the patients was 37 years. The fractures were mostly caused by fall from height (60.84%) and were located at the condylar neck (53.61%). Most of the patients had other associated maxillofacial injuries (71.08%) which were mostly located at symphysis and parasymphysis (44.59%). It took 12.58 +/- 0.35 days of hospitalization for the treatment. Fall from height was the most prevalent cause of mandibular condylar injury in mountainous urban China. The people at highest risk were middle-aged men. Mandibular condylar fracture was mostly located at the condylar neck and was usually associated with fracture at the symphysis and parasymphysis.

Leg Length Versus Torso Length in Pedophilia: Further Evidence of Atypical Physical Development Early in Life.

PubMed

Fazio, Rachel L; Dyshniku, Fiona; Lykins, Amy D; Cantor, James M

2017-08-01

Adult men's height results from an interaction among positive and negative influences, including genetic predisposition, conditions in utero, and influences during early development such as nutritional quality, pathogen exposure, and socioeconomic status. Decreased height, reflected specifically as a decreased leg length, is strongly associated with increased risk of poorer health outcomes. Although prior research has repeatedly shown that pedophiles are shorter than nonpedophiles, the largest study to date relied on self-reported height. In the present study, pedophiles demonstrated reduced measured height and reduced leg length as compared with teleiophiles. Given the prenatal and early childhood origins of height, these findings contribute additional evidence to a biological, developmental origin of pedophilia. In addition, the magnitude of this height difference was substantially larger than that found in children exposed to a variety of early environmental stressors, but similar to that seen in other biologically based neurodevelopmental disorders.

Do parental heights influence pregnancy length?: a population-based prospective study, HUNT 2

PubMed Central

2013-01-01

Background The objective of this study was to examine the association of maternal and paternal height with pregnancy length, and with the risk of pre- and post-term birth. In addition we aimed to study whether cardiovascular risk factors could explain possible associations. Methods Parents who participated in the Nord-Trøndelag Health Study (HUNT 2; 1995–1997) were linked to offspring data from the Medical Birth Registry of Norway (1997–2005). The main analyses included 3497 women who had delivered 5010 children, and 2005 men who had fathered 2798 pregnancies. All births took place after parental participation in HUNT 2. Linear regression was used to estimate crude and adjusted differences in pregnancy length according to parental heights. Logistic regression was used to estimate crude and adjusted associations of parental heights with the risk of pre- and post-term births. Results We found a gradual increase in pregnancy length by increasing maternal height, and the association was essentially unchanged after adjustment for maternal cardiovascular risk factors, parental age, offspring sex, parity, and socioeconomic measures. When estimated date of delivery was based on ultrasound, the difference between mothers in the lower height quintile (<163 cm cm) and mothers in the upper height quintile (≥ 173 cm) was 4.3 days, and when estimated date of delivery was based on last menstrual period (LMP), the difference was 2.8 days. Shorter women (< 163 cm) had lower risk of post-term births, and when estimated date of delivery was based on ultrasound they also had higher risk of pre-term births. Paternal height was not associated with pregnancy length, or with the risks of pre- and post-term births. Conclusions Women with shorter stature had shorter pregnancy length and lower risk of post-term births than taller women, and when EDD was based on ultrasound, they also had higher risk of preterm births. The effect of maternal height was generally stronger when pregnancy length was based on second trimester ultrasound compared to last menstrual period. The association of maternal height with pregnancy length could not be explained by cardiovascular risk factors. Paternal height was neither associated with pregnancy length nor with the risk of pre- and post-term birth. PMID:23383756

Short segment pedicle screw instrumentation and augmentation vertebroplasty in lumbar burst fractures: an experience

PubMed Central

Akbar, Saleem; Dhar, Shabir A.

2008-01-01

To assess the efficacy and feasibility of vertebroplasty and posterior short-segment pedicle screw fixation for the treatment of traumatic lumbar burst fractures. Short-segment pedicle screw instrumentation is a well described technique to reduce and stabilize thoracic and lumbar spine fractures. It is relatively a easy procedure but can only indirectly reduce a fractured vertebral body, and the means of augmenting the anterior column are limited. Hardware failure and a loss of reduction are recognized complications caused by insufficient anterior column support. Patients with traumatic lumbar burst fractures without neurologic deficits were included. After a short segment posterior reduction and fixation, bilateral transpedicular reduction of the endplate was performed using a balloon, and polymethyl methacrylate cement was injected. Pre-operative and post-operative central and anterior heights were assessed with radiographs and MRI. Sixteen patients underwent this procedure, and a substantial reduction of the endplates could be achieved with the technique. All patients recovered uneventfully, and the neurologic examination revealed no deficits. The post-operative radiographs and magnetic resonance images demonstrated a good fracture reduction and filling of the bone defect without unwarranted bone displacement. The central and anterior height of the vertebral body could be restored to 72 and 82% of the estimated intact height, respectively. Complications were cement leakage in three cases without clinical implications and one superficial wound infection. Posterior short-segment pedicle fixation in conjunction with balloon vertebroplasty seems to be a feasible option in the management of lumbar burst fractures, thereby addressing all the three columns through a single approach. Although cement leakage occurred but had no clinical consequences or neurological deficit. PMID:18193300

Three-dimensional finite-element analysis of chevron-notched fracture specimens

NASA Technical Reports Server (NTRS)

Raju, I. S.; Newman, J. C., Jr.

1984-01-01

Stress-intensity factors and load-line displacements were calculated for chevron-notched bar and rod fracture specimens using a three-dimensional finite-element analysis. Both specimens were subjected to simulated wedge loading (either uniform applied displacement or uniform applied load). The chevron-notch sides and crack front were assumed to be straight. Crack-length-to-specimen width ratios (a/w) ranged from 0.4 to 0.7. The width-to-thickness ratio (w/B) was 1.45 or 2. The bar specimens had a height-to-width ratio of 0.435 or 0.5. Finite-element models were composed of singularity elements around the crack front and 8-noded isoparametric elements elsewhere. The models had about 11,000 degrees of freedom. Stress-intensity factors were calculated by using a nodal-force method for distribution along the crack front and by using a compliance method for average values. The stress intensity factors and load-line displacements are presented and compared with experimental solutions from the literature. The stress intensity factors and load-line displacements were about 2.5 and 5 percent lower than the reported experimental values, respectively.

Impact of comorbidities on hospitalization costs following hip fracture.

PubMed

Nikkel, Lucas E; Fox, Edward J; Black, Kevin P; Davis, Charles; Andersen, Lucille; Hollenbeak, Christopher S

2012-01-04

Hip fractures are common in the elderly, and patients with hip fractures frequently have comorbid illnesses. Little is known about the relationship between comorbid illness and hospital costs or length of stay following the treatment of hip fracture in the United States. We hypothesized that specific individual comorbid illnesses and multiple comorbid illnesses would be directly related to the hospitalization costs and the length of stay for older patients following hip fracture. With use of discharge data from the 2007 Nationwide Inpatient Sample, 32,440 patients who were fifty-five years or older with an isolated, closed hip fracture were identified. Using generalized linear models, we estimated the impact of comorbidities on hospitalization costs and length of stay, controlling for patient, hospital, and procedure characteristics. Hypertension, deficiency anemias, and fluid and electrolyte disorders were the most common comorbidities. The patients had a mean of three comorbidities. Only 4.9% of patients presented without comorbidities. The average estimated cost in our reference patient was $13,805. The comorbidity with the largest increased hospitalization cost was weight loss or malnutrition, followed by pulmonary circulation disorders. Most other comorbidities significantly increased the cost of hospitalization. Compared with internal fixation of the hip fracture, hip arthroplasty increased hospitalization costs significantly. Comorbidities significantly affect the cost of hospitalization and length of stay following hip fracture in older Americans, even while controlling for other variables.

Measuring Crack Length in Coarse Grain Ceramics

NASA Technical Reports Server (NTRS)

Salem, Jonathan A.; Ghosn, Louis J.

2010-01-01

Due to a coarse grain structure, crack lengths in precracked spinel specimens could not be measured optically, so the crack lengths and fracture toughness were estimated by strain gage measurements. An expression was developed via finite element analysis to correlate the measured strain with crack length in four-point flexure. The fracture toughness estimated by the strain gaged samples and another standardized method were in agreement.

Estimation of the REV Size and Equivalent Permeability Coefficient of Fractured Rock Masses with an Emphasis on Comparing the Radial and Unidirectional Flow Configurations

NASA Astrophysics Data System (ADS)

Wang, Zhechao; Li, Wei; Bi, Liping; Qiao, Liping; Liu, Richeng; Liu, Jie

2018-05-01

A method to estimate the representative elementary volume (REV) size for the permeability and equivalent permeability coefficient of rock mass with a radial flow configuration was developed. The estimations of the REV size and equivalent permeability for the rock mass around an underground oil storage facility using a radial flow configuration were compared with those using a unidirectional flow configuration. The REV sizes estimated using the unidirectional flow configuration are much higher than those estimated using the radial flow configuration. The equivalent permeability coefficient estimated using the radial flow configuration is unique, while those estimated using the unidirectional flow configuration depend on the boundary conditions and flow directions. The influences of the fracture trace length, spacing and gap on the REV size and equivalent permeability coefficient were investigated. The REV size for the permeability of fractured rock mass increases with increasing the mean trace length and fracture spacing. The influence of the fracture gap length on the REV size is insignificant. The equivalent permeability coefficient decreases with the fracture spacing, while the influences of the fracture trace length and gap length are not determinate. The applicability of the proposed method to the prediction of groundwater inflow into rock caverns was verified using the measured groundwater inflow into the facility. The permeability coefficient estimated using the radial flow configuration is more similar to the representative equivalent permeability coefficient than those estimated with different boundary conditions using the unidirectional flow configuration.

The Comprehensive AOCMF Classification System: Condylar Process Fractures - Level 3 Tutorial

PubMed Central

Neff, Andreas; Cornelius, Carl-Peter; Rasse, Michael; Torre, Daniel Dalla; Audigé, Laurent

2014-01-01

This tutorial outlines the detailed system for fractures of the condylar process at the precision level 3 and is organized in a sequence of sections dealing with the description of the classification system within topographical subdivisions along with rules for fracture coding and a series of case examples with clinical imaging. Basically, the condylar process comprises three fracture levels and is subdivided into the head region, the condylar neck, and the condylar base. Fractures of the condylar head show typical fracture lines either within the lateral pole zone, which may lead to loss of vertical height, or medially to the pole zone, with the latter ones usually not compromising the vertical condyle to fossa relation. In condylar head fractures, the morphology is further described by the presence of minor or major fragmentation, the vertical apposition of fragments at the plane of the head fracture, the displacement of the condylar head with regard to the fossa including a potential distortion of the condylar head congruency resulting in dystopic condyle to fossa relations and the presence or absence of a loss of vertical ramus height. A specific vertical fracture pattern extending from the head to the neck or base subregion is considered. Fractures of the condylar neck and base can be differentiated according to a newly introduced one-third to two-thirds rule with regard to the proportion of the fracture line above and below the level of the sigmoid notch, which is presented in the classification article, and are basically subdivided according to the presence or absence of displacement or dislocation. In both condylar neck and base fractures, the classification is again based on the above mentioned parameters such as fragmentation, displacement of the condylar head with regard to the fossa, including dystopic condyle to fossa relations and loss of vertical ramus height, that is, according to the measurement of the condylar process. In addition, the classification assesses a sideward displacement including the respective displacement sector at the neck or base fracture site as well as the angulation of the superior main fragment and also considers a potential displacement of the caudal fragment with regard to the fossa, which may occur in fractures affecting additional fracture locations in the mandible. The design of this classification is discussed along with a review of existing classification systems. The condylar process for fracture location was defined according to the level 2 system presented in a previous tutorial in this special issue. PMID:25489390

The Comprehensive AOCMF Classification System: Condylar Process Fractures - Level 3 Tutorial.

PubMed

Neff, Andreas; Cornelius, Carl-Peter; Rasse, Michael; Torre, Daniel Dalla; Audigé, Laurent

2014-12-01

This tutorial outlines the detailed system for fractures of the condylar process at the precision level 3 and is organized in a sequence of sections dealing with the description of the classification system within topographical subdivisions along with rules for fracture coding and a series of case examples with clinical imaging. Basically, the condylar process comprises three fracture levels and is subdivided into the head region, the condylar neck, and the condylar base. Fractures of the condylar head show typical fracture lines either within the lateral pole zone, which may lead to loss of vertical height, or medially to the pole zone, with the latter ones usually not compromising the vertical condyle to fossa relation. In condylar head fractures, the morphology is further described by the presence of minor or major fragmentation, the vertical apposition of fragments at the plane of the head fracture, the displacement of the condylar head with regard to the fossa including a potential distortion of the condylar head congruency resulting in dystopic condyle to fossa relations and the presence or absence of a loss of vertical ramus height. A specific vertical fracture pattern extending from the head to the neck or base subregion is considered. Fractures of the condylar neck and base can be differentiated according to a newly introduced one-third to two-thirds rule with regard to the proportion of the fracture line above and below the level of the sigmoid notch, which is presented in the classification article, and are basically subdivided according to the presence or absence of displacement or dislocation. In both condylar neck and base fractures, the classification is again based on the above mentioned parameters such as fragmentation, displacement of the condylar head with regard to the fossa, including dystopic condyle to fossa relations and loss of vertical ramus height, that is, according to the measurement of the condylar process. In addition, the classification assesses a sideward displacement including the respective displacement sector at the neck or base fracture site as well as the angulation of the superior main fragment and also considers a potential displacement of the caudal fragment with regard to the fossa, which may occur in fractures affecting additional fracture locations in the mandible. The design of this classification is discussed along with a review of existing classification systems. The condylar process for fracture location was defined according to the level 2 system presented in a previous tutorial in this special issue.

Measurement of width and pressure in a propagating hydraulic fracture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.

Measurements of width and pressure in a propagating hydraulic fracture have been made in tests conducted at DOE's Nevada Test Site. This was accomplished by creating an instrumented fracture at a tunnel complex (at a depth of 1400 ft) where realistic in situ conditions prevail, particularly with respect to stress and geologic features such as natural fractures and material anisotropy. Analyses of these data show that the pressure drop along the fracture length is much larger than predicted by viscous theory and currently in use in models today. This is apparently due to the tortuosity of the fracture path, multiplemore » fracture strands, roughness and sharp turns (corners) in the flow path due to natural fractures and rock property variations. It suggests that fracture design models need to be updated to include a more realistic friction factor so that fracture lengths are not overestimated.« less

Common normal variants of pediatric vertebral development that mimic fractures: a pictorial review from a national longitudinal bone health study

PubMed Central

Jaremko, Jacob Lester; Siminoski, Kerry; Firth, Gregory; Matzinger, Mary Ann; Shenouda, Nazih; Konji, Victor N.; Roth, Johannes; Sbrocchi, Anne Marie; Reed, Martin; O’Brien, Kathleen; Nadel, Helen; McKillop, Scott; Kloiber, Reinhard; Dubois, Josée; Coblentz, Craig; Charron, Martin; Ward, Leanne M.

2015-01-01

Children with glucocorticoid-treated illnesses are at risk for osteoporotic vertebral fractures and growing awareness has led to increased monitoring for these fractures. However scant literature describes developmental changes in vertebral morphology that can mimic fractures. The goal of this paper is to aid in distinguishing between normal variants and fractures. We illustrate differences using lateral spine radiographs obtained annually from children recruited to the Canada-wide STeroid-Associated Osteoporosis in the Pediatric Population (STOPP) observational study, in which 400 children with glucocorticoid-treated leukemia, rheumatic disorders, and nephrotic syndrome were enrolled near glucocorticoid initiation and followed prospectively for 6 years. Normal variants mimicking fractures exist in all regions of the spine and fall into two groups. The first group comprises variants mimicking pathological vertebral height loss, including not-yet-ossified vertebral apophyses superiorly and inferiorly which can lead to a vertebral shape easily over-interpreted as anterior wedge fracture, physiologic beaking, and spondylolisthesis associated with shortened posterior vertebral height. The second group includes variants mimicking other radiologic signs of fractures: anterior vertebral artery groove resembling an anterior buckle fracture, Cupid’s bow balloon disk morphology, Schmorl nodes mimicking concave endplate fractures, and parallax artifact resembling endplate interruption or biconcavity. If an unexpected vertebral body contour is detected, careful attention to its location, detailed morphology, and (if available) serial changes over time may clarify whether it is a fracture requiring change in management or simply a normal variant. Awareness of the variants described in this paper can improve accuracy in the diagnosis of pediatric vertebral fractures. PMID:25828359

Hormonal and biochemical parameters and osteoporotic fractures in elderly men.

PubMed

Center, J R; Nguyen, T V; Sambrook, P N; Eisman, J A

2000-07-01

Low testosterone has been associated with hip fracture in men in some studies. However, data on other hormonal parameters and fracture outcome in men is minimal. This study examined the association between free testosterone (free T) estradiol (E2), sex hormone-binding globulin (SHBG), 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), insulin-like growth factor I (IGF-I), and fracture in 437 elderly community-dwelling men. Age, height, weight, quadriceps strength, femoral neck bone mineral density (FN BMD), and fracture data (1989-1997) also were obtained. Fractures were classified as major (hip, pelvis, proximal tibia, multiple rib, vertebral, and proximal humerus) or minor (remaining distal upper and lower limb fractures). Fifty-four subjects had a fracture (24 major and 30 minor). There was no association between minor fractures and any hormonal parameter. Risk of major fracture was increased 2-fold for each SD increase in age, decrease in weight and height, and increase in SHBG, and risk of major fracture was increased 3-fold for each SD decrease in quadriceps strength, FN BMD, and 25(OH)D (univariate logistic regression). Independent predictors of major fracture were FN BMD, 2.7 (1.5-4.7; odds ratio [OR]) and 95% confidence interval [CI]); 25(OH)D, 2.8 (1.5-5.3); and SHBG, 1.7 (1.2-2.4). An abnormal value for three factors resulted in a 30-fold increase in risk but only affected 2% of the population. It is not immediately apparent how 25(OH)D and SHBG, largely independently of BMD, may contribute to fracture risk. They may be markers for biological age or health status not measured by methods that are more traditional and as such may be useful in identifying those at high risk of fracture.

A comparative study of high-viscosity cement percutaneous vertebroplasty vs. low-viscosity cement percutaneous kyphoplasty for treatment of osteoporotic vertebral compression fractures.

PubMed

Sun, Kai; Liu, Yang; Peng, Hao; Tan, Jun-Feng; Zhang, Mi; Zheng, Xian-Nian; Chen, Fang-Zhou; Li, Ming-Hui

2016-06-01

The clinical effects of two different methods-high-viscosity cement percutaneous vertebroplasty (PVP) and low-viscosity cement percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fractures (OVCFs) were investigated. From June 2010 to August 2013, 98 cases of OVCFs were included in our study. Forty-six patients underwent high-viscosity PVP and 52 patients underwent low-viscosity PKP. The occurrence of cement leakage was observed. Pain relief and functional activity were evaluated using the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI), respectively. Restoration of the vertebral body height and angle of kyphosis were assessed by comparing preoperative and postoperative measurements of the anterior heights, middle heights and the kyphotic angle of the fractured vertebra. Nine out of the 54 vertebra bodies and 11 out of the 60 vertebra bodies were observed to have cement leakage in the high-viscosity PVP and low-viscosity PKP groups, respectively. The rate of cement leakage, correction of anterior vertebral height and kyphotic angles showed no significant differences between the two groups (P>0.05). Low-viscosity PKP had significant advantage in terms of the restoration of middle vertebral height as compared with the high-viscosity PVP (P<0.05). Both groups showed significant improvements in pain relief and functional capacity status after surgery (P<0.05). It was concluded that high-viscosity PVP and low-viscosity PKP have similar clinical effects in terms of the rate of cement leakage, restoration of the anterior vertebral body height, changes of kyphotic angles, functional activity, and pain relief. Low-viscosity PKP is better than high-viscosity PVP in restoring the height of the middle vertebra.

Preventive effects of conservative treatment with short-term teriparatide on the progression of vertebral body collapse after osteoporotic vertebral compression fracture.

PubMed

Park, J-H; Kang, K-C; Shin, D-E; Koh, Y-G; Son, J-S; Kim, B-H

2014-02-01

The progression of fractured vertebral collapse is not rare after a conservative treatment of vertebral compression fracture (VCF). Teriparatide has been shown to directly stimulate bone formation and improve bone density, but there is a lack of evidence regarding its use in fracture management. Conservative treatment with short-term teriparatide is effective for decreasing the progression of fractured vertebral body collapse. Few studies have reported on the prevention of collapsed vertebral body progression after osteoporotic VCF. Teriparatide rapidly enhances bone formation and increases bone strength. This study evaluated preventive effects of short-term teriparatide on the progression of vertebral body collapse after osteoporotic VCF. Radiographs of 68 women with single-level osteoporotic VCF at thoracolumbar junction (T11-L2) were reviewed. Among them, 32 patients were treated conservatively with teriparatide (minimum 3 months) (group I), and 36 were treated with antiresorptive (group II). We measured kyphosis and wedge angle of the fractured vertebral body, and ratios of anterior, middle, and posterior heights of the collapsed body to posterior height of a normal upper vertebra were determined. The degree of collapse progression was compared between two groups. The progression of fractured vertebral body collapse was shown in both groups, but the degree of progression was significantly lower in group I than in group II. At the last follow-up, mean increments of kyphosis and wedge angle were significantly lower in group I (4.0° ± 4.2° and 3.6° ± 3.6°) than in group II (6.8° ± 4.1° and 5.8° ± 3.5°) (p = 0.032 and p = 0.037). Decrement percentages of anterior and middle border height were significantly lower in group I (9.6 ± 10.3 and 7.4 ± 7.5 %) than in group II (18.1 ± 9.7 and 13.8 ± 12.2 %) (p = 0.001 and p = 0.025), but not in posterior height (p = 0.086). In female patients with single-level osteoporotic VCF at the thoracolumbar junction, short-term teriparatide treatment did not prevent but did decrease the progression of fractured vertebral body collapse.

[Relation between Body Height and Combined Length of Manubrium and Mesosternum of Sternum Measured by CT-VRT in Southwest Han Population].

PubMed

Luo, Ying-zhen; Tu, Meng; Fan, Fei; Zheng, Jie-qian; Yang, Ming; Li, Tao; Zhang, Kui; Deng, Zhen-hua

2015-06-01

To establish the linear regression equation between body height and combined length of manubrium and mesostenum of sternum measured by CT volume rendering technique (CT-VRT) in southwest Han population. One hundred and sixty subjects, including 80 males and 80 females were selected from southwest Han population for routine CT-VRT (reconstruction thickness 1 mm) examination. The lengths of both manubrium and mesosternum were recorded, and the combined length of manubrium and mesosternum was equal to the algebraic sum of them. The sex-specific linear regression equations between the combined length of manubrium and mesosternum and the real body height of each subject were deduced. The sex-specific simple linear regression equations between the combined length of manubrium and mesostenum (x3) and body height (y) were established (male: y = 135.000+2.118 x3 and female: y = 120.790+2.808 x3). Both equations showed statistical significance (P < 0.05) with a 100% predictive accuracy. CT-VRT is an effective method for measurement of the index of sternum. The combined length of manubrium and mesosternum from CT-VRT can be used for body height estimation in southwest Han population.

Complex Contact Angles Calculated from Capillary Rise Measurements on Rock Fracture Faces

NASA Astrophysics Data System (ADS)

Perfect, E.; Gates, C. H.; Brabazon, J. W.; Santodonato, L. J.; Dhiman, I.; Bilheux, H.; Bilheux, J. C.; Lokitz, B. S.

2017-12-01

Contact angles for fluids in unconventional reservoir rocks are needed for modeling hydraulic fracturing leakoff and subsequent oil and gas extraction. Contact angle measurements for wetting fluids on rocks are normally performed using polished flat surfaces. However, such prepared surfaces are not representative of natural rock fracture faces, which have been shown to be rough over multiple scales. We applied a variant of the Wilhelmy plate method for determining contact angle from the height of capillary rise on a vertical surface to the wetting of rock fracture faces by water in the presence of air. Cylindrical core samples (5.05 cm long x 2.54 cm diameter) of Mancos shale and 6 other rock types were investigated. Mode I fractures were created within the cores using the Brazilian method. Each fractured core was then separated into halves exposing the fracture faces. One fracture face from each rock type was oriented parallel to a collimated neutron beam in the CG-1D imaging instrument at ORNL's High Flux Isotope Reactor. Neutron radiography was performed using the multi-channel plate detector with a spatial resolution of 50 μm. Images were acquired every 60 s after a water reservoir contacted the base of the fracture face. The images were normalized to the initial dry condition so that the upward movement of water on the fracture face was clearly visible. The height of wetting at equilibrium was measured on the normalized images using ImageJ. Contact angles were also measured on polished flat surfaces using the conventional sessile drop method. Equilibrium capillary rise on the exposed fracture faces was up to 8.5 times greater than that predicted for polished flat surfaces from the sessile drop measurements. These results indicate that rock fracture faces are hyperhydrophilic (i.e., the height of capillary rise is greater than that predicted for a contact angle of zero degrees). The use of complex numbers permitted calculation of imaginary contact angles for such surfaces. This analysis yielded a continuum of contact angles (real above, and imaginary below, zero degrees) that can be used to investigate relationships with properties such surface roughness and porosity. It should be noted these are preliminary, unreplicated results and further research will be needed to verify them and refine the approach.

[Application and research progress of subtalar distraction bone block arthrodesis in treatment of calcaneus fracture malunion].

PubMed

Wang, Shanxi; Li, Jun; Huang, Fuguo; Liu, Lei

2017-05-01

To review the application and research progress of subtalar distraction bone block arth-rodesis in the treatment of calcaneus fracture malunion. The recent literature concerning the history, surgical technique, postoperative complication, indications, and curative effect of subtalar distraction arthrodesis with bone graft block interposition in the treatment of calcaneus fracture malunion was summarized and analyzed. Subtalar distraction bone block arthrodesis is one of the main ways to treat calcaneus fracture malunion, including a combined surgery with subtalar arthrodesis and realignment surgery for hindfoot deformity using bone block graft. The advantage is on the base of subtalar joint fusion, through one-time retracting subtalar joint, the posterior articular surface of subtalar joint implants bone block can partially restore calcaneal height, thus improving the function of the foot. Compared with other calcaneal malunion treatments, subtalar distraction arthrodesis is effective to correct complications caused by calcaneus fracture malunion, and it can restore the height of talus and calcaneus, correct loss of talocalcaneal angle, and ease pain. Subtalar distraction bone block arthrodesis has made remarkable progress in the treatment of calcaneus fracture malunion, but it has the disadvantages of postoperative nonunion and absorption of bone block, so further study is needed.

MANAGEMENT OF BILATERAL FEMORAL NECK FRACTURE IN A NONAGENARIAN PATIENT--CASE REPORT.

PubMed

Popescu, D; Trandabaţ, C; Puha, B; Veliceasa, B; Alexa, O

2016-01-01

Simultaneous bilateral femoral neck fracture is rare injury. Cases with this type of fracture have been reported in the literature since the 1950s, following the introduction of electroconvulsive therapy which generates violent hip muscle contractions. In young patients' simultaneous bilateral femoral neck fracture results from high energy trauma (car accident or fall from height) in a normal bone. Pathological changes in bone structure occurring in chronic kidney disease, vitamin D deficiency, osteomalacia, osteoporosis, metabolic imbalances and administration of corticosteroids explain the occurrence of this particular type of fracture following low-energy trauma. We present the case of a 90-year-old female patient who suffered a simple fall from her own height resulting in a Garden IV bilateral femoral neck fracture. Our therapeutic option in this patient was bilateral uncemented bipolar hemiarthroplasty in a single session using a single tray of sterile surgical instruments and two sterile drapes. Postoperative outcome was very good, allowing the initiation of functional recovery on the first postoperative day. Uncemented hemiarthroplasty proved to be a good choice in such a patient in the associated diseases may trigger the risk of cardiovascular disturbances specific to bone cement implantation syndrome.

Microseismicity Induced by Hydraulic Fracturing in Oil and Gas Wells

NASA Astrophysics Data System (ADS)

Warpinski, N. R.; Maxwell, S.; Waltman, C.

2006-12-01

The detection and analysis of microseismicity induced by injection of fluids at high pressure has proved to be an effective technology for monitoring the placement of the fluid in applications such as hydraulic fracture stimulation of oil and gas wells, "shear-dilation" enhancement of hot-dry-rock reservoirs, waterflooding and tertiary recovery processes in oil reservoirs, CO2 injection for sequestration, drill cuttings injection, and many others. Microseismic mapping of hydraulic fractures, in particular, has grown into an extensive industry that provides critical information on many facets of fracture behavior and the overall geometry, with the results showing both expected and unexpected behavior in various tests. These industrial fractures are typically mapped with arrays of downhole tri-axial receivers placed in one or more wells at the reservoir level. With the number of microseismically mapped fractures now exceeding 1,000, numerous observations and inferences about fracture mechanisms can be made. In a large group of reservoirs, the created hydraulic fractures are mostly planar and follow a consistent azimuth. In other reservoirs, such as naturally fractured shales similar to the Barnett shale in the Fort Worth basin, the created fracture is highly dependent on the treatment. In these shale reservoirs, the use of viscous gels results in a mostly planar geometry, but stimulations with high-rate, large-volume "waterfracs" result in network fractures that may exceed 400 m by 1200 m in areal extent. In horizontal wells where several stages of these waterfracs are commonly pumped, the stages are found to often interfere and redirect subsequent stages. In many reservoirs, the heights of the hydraulic fractures have been found to be less than the expected heights based on known or inferred in situ stress contrasts between the reservoir layer and the bounding rocks, suggesting that some properties of the layering are important for limiting height growth. In lenticular sandstones, fractures are commonly observed to follow the sandstone lithologies and migrate upward or downward to remain within the accreted sandstone beds. A number of mapping tests have been performed in environments where the hydraulic fracture has interacted with faults. In such cases, the log-scale relative magnitudes of the events may suddenly increase by two or more. The faults often extend hundreds of meters upward or downward out of zone, or in directions different from the initial hydraulic fracture. Overall, the orientations and dimensions of the mapped fractures are providing the necessary information to optimize field development and improve hydraulic fracture effectiveness. In addition, these tests are providing important clues to help understand the geomechanical conditions of the reservoir and the changes induced by hydraulic fracturing.

Cemented Fractures in Mountain Inside Gale Crater on Mars

NASA Image and Video Library

2011-07-22

One type of feature of scientific interest on the mountain inside Gale crater is exposure of cemented fractures, evidence that groundwater once reached to at least that height of the mountain. This image is from NASA Mars Reconnaissance Orbiter.

Effect of using truncated versus total foot length to calculate the arch height ratio.

PubMed

McPoil, Thomas G; Cornwall, Mark W; Vicenzino, Bill; Teyhen, Deydre S; Molloy, Joseph M; Christie, Douglas S; Collins, Natalie

2008-12-01

The purpose of this study was to determine the arch height ratio in a large cohort of subjects as well as to assess the reliability and validity of the foot measurements utilized in the study. Eight hundred and fifty subjects, 393 women and 457 men, consented to participate in the study. The dorsal arch height, total foot length, and the truncated foot length were used to calculate two variations of the arch height ratio. In addition to determining within- and between-rater measurement reliability, radiographs were used to establish validity. The truncated arch height ratio can be estimated using the total foot length, unless toe deformities are present in the individual being assessed. All foot measurements had high levels of intra- and inter-rater reliability and the validity of measuring the dorsal arch height while standing with equal weight on both feet was established. This investigation provides normative values from a large cohort of healthy female and male subjects for two variations of the arch height ratio. The arch height ratio is a reliable and valid measurement that may prove useful to clinicians and researchers for the classification of foot posture.

Measurement of width and pressure in a propagating hydraulic fracture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.

Measurements of width and pressure in a propagating hydraulic fracture have been made in tests conducted at the U.S. DOE's Nevada test site. This was accomplished by creating an ''instrumented fracture'' at a tunnel complex (at a depth of 1,400 ft (425 m)) where realistic insitu conditions prevail, particularly with respect to stress and geologic features such as natural fractures and material anisotropy. Analyses of these data show that the pressure drop along the fracture length is much larger than predicted by viscous theory, which currently is used in models. This apparently is caused by the tortuosity of the fracturemore » path, multiple fracture strands, roughness, and sharp turns (corners) in the flow path resulting from natural fractures and rock property variations. It suggests that fracture design models need to be updated to include a more realistic friction factor so that fracture lengths are not overestimated.« less

Measurement of width and pressure in a propagating hydraulic fracture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.

Measurements of width and pressure in a propagating hydraulic fracture have been made in tests conducted at DOE's Nevada Test Site. This was accomplished by creating an ''instrumented fracture'' at a tunnel complex (at a depth of 1400 ft) where realistic in-situ conditions prevail, particularly with respect to stress and geologic features such as natural fractures and material anisotropy. Analyses of these data show that the pressure drop along the fracture length is much larger than predicted by viscous theory and currently in use in models today. This is apparently due to the tortuosity of the fracture path, multiple fracturemore » strands, roughness and sharp turns (corners) in the flow path due to natural fractures and rock property variations. It suggests that fracture design models need to be updated to include a more realistic friction factor so that fracture lengths are not overestimated.« less

Geographical Distribution of Adolescent Body Height with Respect to Effective Day Length in Japan: An Ecological Analysis

PubMed Central

Yokoya, Masana; Shimizu, Hideyasu; Higuchi, Yukito

2012-01-01

The height of Japanese youth raised in the northern region tends to be greater than that of youth raised in the southern region; therefore, a geographical gradient in youth body height exists. Although this gradient has existed for about 100 years, the reasons for it remain unclear. Consideration of the nutritional improvement, economic growth, and intense migration that has occurred in this period indicates that it is probably the result of environmental rather than nutritional or genetic factors. To identify possible environmental factors, ecological analysis of prefecture-level data on the body size of 8- to 17-year-old youth averaged over a 13-year period (1996 to 2008) and Japanese mesh climatic data on the climatic variables of temperature, solar radiation, and effective day length (duration of photoperiod exceeding the threshold of light intensity) was performed. The geographical distribution of the standardized height of Japanese adolescents was found to be inversely correlated to a great extent with the distribution of effective day length at a light intensity greater than 4000 lx. The results of multiple regression analysis of effective day length, temperature, and weight (as an index of food intake) indicated that a combination of effective day length and weight was statistically significant as predictors of height in early adolescence; however, only effective day length was statistically significant as a predictor of height in late adolescence. Day length may affect height by affecting the secretion of melatonin, a hormone that inhibits sexual and skeletal maturation, which in turn induces increases in height. By affecting melatonin production, regional differences in the duration of the photoperiod may lead to regional differences in height. Exposure to light intensity greater than 4000 lx appears to be the threshold at which light intensity begins to affect the melatonin secretion of humans who spend much of their time indoors. PMID:23227226

Comparing hospital outcomes between open and closed tibia fractures treated with intramedullary fixation.

PubMed

Smith, Evan J; Kuang, Xiangyu; Pandarinath, Rajeev

2017-07-01

Tibial shaft fractures comprise a large portion of operatively treated long bone fractures, and present with the highest rate of open injuries. Intramedullary fixation has become the standard of care for both open and closed injuries. The rates of short term complications and hospital length of stay for open and closed fractures treated with intramedullary fixation is not fully known. Previous series on tibia fractures were performed at high volume centers, and data were not generalizable, further they did not report on length of stay and the impact of preoperative variables on infections, complications and reoperation. We used a large surgical database to compare these outcomes while adjusting for preoperative risk factors. Data were extracted from the ACS-NSQIP database from 2005 to 2014. Cases were identified based on CPT codes for intramedullary fixation and categorized as closed vs open based on ICD9 code. In addition to demographic and case data, primary analysis examined correlation between open and closed fracture status with infection, complications, reoperation and hospital length of stay. Secondary analysis examined preoperative variables including gender, race, age, BMI, and diabetes effect on outcomes. There were 272 cases identified. There were no significant demographic differences between open and closed tibia fracture cases. Open fracture status did not increase the rate of infection, 30day complications, reoperation, or length of stay. The only preoperative factor that correlated with length of stay was age. There was no correlation between BMI, presence of insulin dependent and nondependent diabetes, and any outcome measure. When considering the complication rates for open and closed tibial shaft fractures treated with intramedullary fixation, there is no difference between 30-day complication rate, length of stay, or return to the operating room. Our reported postoperative infection rates were comparable to previous series, adding validity to our results. The heterogeneity of the hospitals included in ACS-NSQIP database allow our data to be generalizable. These methods may underrepresent the true occurrence of infection as operatively treated tibia infections may present late, requiring late revision. Despite limitations, the data reflect on the current burden of managing these once devastating injuries. Copyright © 2017 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rybicki, E.F.; Luiskutty, C.T.; Sutrick, J.S.

This research is part of a larger program sponsored by the United States Department of Energy with the objective of developing better methods to produce gas from low permeability formations in western gas sands. This large research program involves several universities and research centers. Each group is involved in a different area of study to answer specific questions. The hydraulic fracturing computer model has three components---a model for fracture geometry, a model for proppant transport, and a computer program that couples the two models. The fracture geometry model was developed at Oral Roberts University and the proppant transport model wasmore » developed at The University of Tulsa prior to the start of the present work. The present work is directed at enhancing the capabilities of these two models and coupling them to obtain a single model for evaluating the final fracture geometry and proppant distribution within the fracture. The report is organized into four parts. Part 1 describes the fracture geometry modeling effort accomplished at Oral Roberts University, NIPER and recently at The University of Tulsa. The proppant transport model, developed for constant height fractures at the University of Tulsa, is contained in Part 2. The coupling of the Proppant Transport Model and the model for the variable height fracture geometry constitutes Part 3 of this report. Part 4 presents a summary of accomplishments and recommendations of this study. 112 refs., 147 figs., 70 tabs.« less

Relating Cohesive Zone Model to Linear Elastic Fracture Mechanics

NASA Technical Reports Server (NTRS)

Wang, John T.

2010-01-01

The conditions required for a cohesive zone model (CZM) to predict a failure load of a cracked structure similar to that obtained by a linear elastic fracture mechanics (LEFM) analysis are investigated in this paper. This study clarifies why many different phenomenological cohesive laws can produce similar fracture predictions. Analytical results for five cohesive zone models are obtained, using five different cohesive laws that have the same cohesive work rate (CWR-area under the traction-separation curve) but different maximum tractions. The effect of the maximum traction on the predicted cohesive zone length and the remote applied load at fracture is presented. Similar to the small scale yielding condition for an LEFM analysis to be valid. the cohesive zone length also needs to be much smaller than the crack length. This is a necessary condition for a CZM to obtain a fracture prediction equivalent to an LEFM result.

Height restoration of osteoporotic vertebral compression fractures using different intravertebral reduction devices: a cadaveric study.

PubMed

Krüger, Antonio; Oberkircher, Ludwig; Figiel, Jens; Floßdorf, Felix; Bolzinger, Florent; Noriega, David C; Ruchholtz, Steffen

2015-05-01

The treatment of osteoporotic vertebral compression fractures using transpedicular cement augmentation has grown significantly during the past two decades. Balloon kyphoplasty was developed to restore vertebral height and improve sagittal alignment. Several studies have shown these theoretical improvements cannot be transferred universally to the clinical setting. The aim of the current study is to evaluate two different procedures used for percutaneous augmentation of vertebral compression fractures with respect to height restoration: balloon kyphoplasty and SpineJack. Twenty-four vertebral bodies of two intact, fresh human cadaveric spines (T6-L5; donor age, 70 years and 60 years; T-score -6.8 points and -6.3 points) were scanned using computed tomography (CT) and dissected into single vertebral bodies. Vertebral wedge compression fractures were created by a material testing machine (Universal testing machine, Instron 5566, Darmstadt, Germany). The axial load was increased continuously until the height of the anterior edge of the vertebral body was reduced by 40% of the initial measured values. After 15 minutes, the load was decreased manually to 100 N. After postfracture CT, the clamped vertebral bodies were placed in a custom-made loading frame with a preload of 100 N. Twelve vertebral bodies were treated using SpineJack (SJ; Vexim, Balma, France), the 12 remaining vertebral bodies were treated with balloon kyphoplasty (BKP; Kyphon, Medtronic, Sunnyvale, CA, USA). The load was maintained during the procedure until the cement set completely. Posttreatment CT was performed. Anterior, central, and posterior height as well as the Beck index were measured prefracture and postfracture as well as after treatment. For anterior height restoration (BKP, 0.14±1.48 mm; SJ, 3.34±1.19 mm), central height restoration (BKP, 0.91±1.04 mm; SJ, 3.24±1.22 mm), and posterior restoration (BKP, 0.37±0.57 mm; SJ, 1.26±1.05), as well as the Beck index (BKP, 0.00±0.06 mm; SJ, 0.10±0.06), the values for the SpineJack group were significantly higher (p<.05) CONCLUSION: The protocols for creating wedge fractures and using the instrumentation under a constant preload of 100 N led to reproducible results and effects. The study showed that height restoration was significantly better in the SpineJack group compared with the balloon kyphoplasty group. The clinical implications include a better restoration of the sagittal balance of the spine and a reduction of the kyphotic deformity, which may relate to clinical outcome and the biological healing process. Copyright © 2015 Elsevier Inc. All rights reserved.

Variation in Resource Utilization for Patients With Hip and Pelvic Fractures Despite Equal Medicare Reimbursement.

PubMed

Samuel, Andre M; Webb, Matthew L; Lukasiewicz, Adam M; Basques, Bryce A; Bohl, Daniel D; Varthi, Arya G; Lane, Joseph M; Grauer, Jonathan N

2016-06-01

Medicare currently reimburses hospitals for inpatient admissions with "bundled" payments based on patient Diagnosis-related Groups (DRGs) regardless of true hospital costs. At present, DRG 536 (fractures of the hip and pelvis) includes a broad spectrum of patients with orthopaedic trauma, likely with varying inpatient resource utilization. With the growing incidence of fractures in the elderly, inadequate reimbursements from Medicare for certain patients with DRG 536 may lead to growing financial strain on healthcare institutions caring for these patients with higher costs. The purposes of the study were to determine whether (1) inpatient length of stay; (2) intensive care unit stay; and (3) ventilator time differ among subpopulations with Medicare DRG 536. A total of 56,683 patients, 65 years or older, with fractures of the hip or pelvis were identified in the 2011 and 2012 National Trauma Data Bank. This clinical registry contains data on trauma cases from more than 900 participating trauma centers, allowing analysis of resource utilization in centers across the United States. Patients were grouped in the following subgroups: hip fractures (n = 35,119), nonoperative pelvic fractures (n = 15,506), acetabulum fractures, operative and nonoperative, (n = 7670), and operative pelvic fractures (n = 682). Total inpatient length of stay, intensive care unit (ICU) stay, and ventilator time were compared across groups using multivariate analysis that controlled for hospital factors. After controlling for patient and hospital factors, difference in inpatient length of stay was -0.2 days for patients with nonoperative pelvis fractures compared with inpatient length of stay for patients with hip fractures (95% CI, -0.4 to -0.1 days; p = 0.001); 1.7 days for patient with acetabulum fractures (95% CI, 1.4-1.9 days; p < 0.001); and 7.7 days for patients with operative pelvic fractures (95% CI, 7.0-8.4 days; p < 0.001). The difference in ICU length of stay for patients with nonoperative pelvis fractures was 0.8 days compared with ICU length of stay for patients with hip fractures (95% CI, 0.7-0.9 days; p < 0.001); 1.9 days for patients with acetabulum fractures (95% CI, 1.8-2.1 days; p < 0.001); and 6.3 days for patients with operative pelvic fractures (95% CI, 5.9-6.7 days; p < 0.001). The difference in mechanical ventilation time for patients with nonoperative fractures was 0.5 days compared with ventilation time for patients with hip fractures (95% CI, 0.4-0.6 days; p < 0.001); 1.1 days for patients with acetabulum fractures (95% CI, 1.0-1.2 days; p < 0.001); and 3.9 days for patients with operative fractures (95% CI, 2.5-3.2 days; p < 0.001). In our current multitiered trauma system, certain centers will see higher proportions of patients with acetabulum and operative pelvic fractures. Because hospitals are reimbursed equally for these subgroups of Medicare DRG 536, centers that care for a greater proportion of patients with more-complex pelvic trauma will experience lower financial margins per trauma patient, limiting their potential for growth and investment compared with competing institutions that may not routinely see patients with high-energy trauma. Because of this, we believe reevaluation of this Medicare Prospective Payment System DRG is warranted. Level IV, economic and decision analysis.

Components of height and blood pressure in childhood

PubMed Central

Regnault, Nolwenn; Kleinman, Ken P; Rifas-Shiman, Sheryl L; Langenberg, Claudia; Lipshultz, Steven E; Gillman, Matthew W

2014-01-01

Background In children being taller is associated with higher blood pressure (BP), but few studies have divided height into its components: trunk and leg length. We examined the associations of total height, trunk length and leg length with systolic BP (SBP), diastolic BP (DBP) and pulse pressure (PP) at early childhood and mid-childhood visits, as well as change between the two visits. Methods We obtained five measures of SBP and DBP at the early childhood visit (N = 1153, follow-up rate = 54%) and at the mid-childhood visit (N = 1086, follow-up rate = 51%) respectively, in Project Viva, a US cohort study. We measured total height and sitting height (a measure of trunk length that includes head and neck) and calculated leg length as the difference between the two. Using mixed models, we adjusted the cross-sectional analyses for leg length when trunk length was the exposure of interest, and vice versa. We also adjusted for maternal race/ethnicity, child age, sex, overall adiposity and BP measurement conditions. Results At the mid-childhood visit, total height was positively associated with SBP [0.34 (0.24; 0.45) mmHg/cm] but not with DBP [0.07 (−0.003; 0.15)]. In models examining trunk and leg length separately, each was positively associated with SBP [0.72 (0.52; 0.92) and 0.33 (0.16; 0.49) respectively]. In a fully adjusted model with both leg and trunk length, only trunk length remained associated with BP. For a given leg length, a 1-cm increment in trunk length was associated with a 0.63-mmHg (0.42; 0.83) higher SBP and a 0.17-mmHg (0.02; 0.31) higher DBP. For a given trunk length, however, the associations of leg length with SBP [0.13 (−0.03; 0.30)] and with DBP [0.002 (−0.11; 0.12)] were null. These patterns were similar at the early childhood visit. Conclusions Children with greater trunk lengths have higher BPs, perhaps because of the additional pressure needed to overcome gravity to perfuse the brain. PMID:24413933

Steeply dipping heaving bedrock, Colorado: Part 1 - Heave features and physical geological framework

USGS Publications Warehouse

Noe, D.C.; Higgins, J.D.; Olsen, H.W.

2007-01-01

Differentially heaving bedrock has caused severe damage near the Denver metropolitan area. This paper describes heave-feature morphologies, the underlying bedrock framework, and their inter-relationship. The heave features are linear to curvilinear and may attain heights of 0.7 m (2.4 ft), widths of 58 m (190 ft), and lengths of 1,067 m (3,500 ft). They are nearly symmetrical to highly asymmetrical in cross section, with width-to-height ratios of 45:1 to 400:1, and most are oriented parallel with the mountain front. The bedrock consists of Mesozoic sedimentary formations having dip angles of 30 degrees to vertical to overturned. Mixed claystone-siltstone bedding sequences up to 36-m (118-ft) thick are common in the heave-prone areas, and interbeds of bentonite, limestone, or sandstone may be present. Highly fractured zones of weathered to variably weathered claystone extend to depths of 19.5 to 22.3 m (64 to 73 ft). Fracture spacings are 0.1 to 0.2 m (0.3 to 0.7 ft) in the weathered and variably weathered bedrock and up to 0.75 m (2.5 ft) in the underlying, unweathered bedrock. Curvilinear shear planes in the weathered claystone show thrust or reverse offsets up to 1.2 m (3.9 ft). Three associations between heave-feature morphologies and the geological framework are recognized: (1) Linear, symmetrical to asymmetrical heaves are associated with primary bedding composition changes. (2) Linear, highly asymmetrical heaves are associated with shear planes along bedding. (3) Curvi-linear, highly asymmetrical heaves are associated with bedding-oblique shear planes.

Photo-anthropometric study on face among Garo adult females of Bangladesh.

PubMed

Akhter, Z; Banu, M L A; Alam, M M; Hossain, S; Nazneen, M

2013-08-01

Facial anthropometry has well-known implications in health-related fields. Measurement of human face is used in identification of person in Forensic medicine, Plastic surgery, Orthodontics, Archeology, Hair-style design and examination of the differences between races and ethnicities. Facial anthropometry provides an indication of the variations in facial shape in a specified population. Bangladesh harbours many cultures and people of different races because of the colonial rules of the past regimes. Standards based on ethnic or racial data are desirable because these standards reflect the potentially different patterns of craniofacial growth resulting from racial, ethnic and sexual differences. In the above context, the present study was attempted to establish ethnic specific anthropometric data for the Christian Garo adult females of Bangladesh. The study was an observational, cross-sectional and primarily descriptive in nature with some analytical components and it was carried out with a total number of 100 Christian Garo adult females aged between 25-45 years. Three vertical facial dimensions such as facial height from 'trichion' to 'gnathion', nasal length and total vermilion height were measured by photographic method. Though these measurements were taken by photographic method but they were converted into actual size using one of the physically measured variables between two angles of the mouth (chilion to chilion). The data were then statistically analyzed by computation to find out its normatic value. The study also observed the possible 'correlation' between the facial height from 'trichion' to 'gnathion' with nasal length and total vermilion height. Multiplication factors were estimated for estimating facial height from nasal length and total vermilion height. Comparison were made between 'estimated' values with the 'measured' values by using't' test. The mean (+/- SD) of nasal length and total vermilion height were 4.53 +/- 0.36 cm and 1.63 +/- 0.23 cm respectively and the mean (+/- SD) of facial height from 'trichion' to 'gnathion' was 16.88 +/- 1.11 cm. Nasal length and total vermilion height showed also a significant positive correlation with facial height from 'trichion' to 'gnathion'. No significant difference was found between the 'measured' and 'estimated' facial height from 'trichion' to 'gnathion' for nasal length and total vermilion height.

The effects of two non-steroidal anti-inflammatory drugs on the mobility of laying hens with keel bone fractures.

PubMed

Nasr, Mohammed Af; Nicol, Christine J; Wilkins, Lindsay; Murrell, Joanna C

2015-03-01

Investigate the effects of administration of meloxicam and carprofen on the mobility of hens with and without keel fractures. Within each of two experiments a 'blinded' randomised cross over design whereby birds received either the test drug (carprofen or meloxicam) or saline. Two groups of Lohman Brown hens with and without keel bone fractures. The first group (n = 63) was treated with carprofen 25 mg kg(-1) and saline subcutaneously, twice. The second group (n = 40) was treated with meloxicam (5 mg kg(-1) ) and saline subcutaneously. The latency of birds to fly down from perches 50, 100 and 150 cm above the ground was measured after each treatment. Data from experiment 1 and 2 were analysed separately; the effects of drug treatment compared with saline on landing time for birds with and without keel bone fractures were evaluated using MLwiN. In both experiments latency to fly down from perches was longer in hens with keel fractures and there was a significant interaction between perch height and fracture status. For carprofen, at the 50 cm, 100 cm and 150 cm perch heights, birds with fractures took (mean ± SD) 2.5 ± 2.9, 6.8 ± 9.7 and 11.5 ± 13.2 seconds respectively to fly down compared with 1.3 ± 0.5, 2.3 ± 1.2 and 4.2 ± 3.1 seconds for birds without fractures. For meloxicam, at the 50 cm, 100 cm and 150 cm perch heights, birds with fractures took 2.9 ± 2.5, 49.8 ± 85.4 and 100.3 ± 123.6 seconds respectively compared with 0.7 ± 0.5, 2.5 ± 7.1 and 3.0 ± 4.6 seconds to fly down for birds without fractures. There was no significant effect of carprofen or meloxicam treatment. These data provide further confirmation that keel fractures reduce the willingness of birds to move from perches. © 2014 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

Correlation Between Fracture Network Properties and Stress Variability in Geological Media

NASA Astrophysics Data System (ADS)

Lei, Qinghua; Gao, Ke

2018-05-01

We quantitatively investigate the stress variability in fractured geological media under tectonic stresses. The fracture systems studied include synthetic fracture networks following power law length scaling and natural fracture patterns based on outcrop mapping. The stress field is derived from a finite-discrete element model, and its variability is analyzed using a set of mathematical formulations that honor the tensorial nature of stress data. We show that local stress perturbation, quantified by the Euclidean distance of a local stress tensor to the mean stress tensor, has a positive, linear correlation with local fracture intensity, defined as the total fracture length per unit area within a local sampling window. We also evaluate the stress dispersion of the entire stress field using the effective variance, that is, a scalar-valued measure of the overall stress variability. The results show that a well-connected fracture system under a critically stressed state exhibits strong local and global stress variabilities.

Mineback Stimulation Research Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.

The objective of the Mineback Stimulation Research Experiments is to improve hydraulic fracture stimulation technology by providing an in situ laboratory where basic processes and mechanisms that control and influence fracture propagation can be observed, measured and understood. While previous tests have been instrumental in providing an understanding of the mechanisms controlling fracture height, current experiments are focused on fluid flow through the created fracture and the associated pressure drops and crack widths. Work performed, accomplishments and future plans are presented. 7 refs., 2 figs.

Development and application of rail defect fracture models to assess remedial actions

DOT National Transportation Integrated Search

1993-08-01

The fracture mechanics models were refined for two types of rail defects - the bolt hole crack and the vertical split head. Beam-type finite element analysis was conducted to determine the effects of joint bar looseness, rail height mismatch and trai...

Multiphase flow models for hydraulic fracturing technology

NASA Astrophysics Data System (ADS)

Osiptsov, Andrei A.

2017-10-01

The technology of hydraulic fracturing of a hydrocarbon-bearing formation is based on pumping a fluid with particles into a well to create fractures in porous medium. After the end of pumping, the fractures filled with closely packed proppant particles create highly conductive channels for hydrocarbon flow from far-field reservoir to the well to surface. The design of the hydraulic fracturing treatment is carried out with a simulator. Those simulators are based on mathematical models, which need to be accurate and close to physical reality. The entire process of fracture placement and flowback/cleanup can be conventionally split into the following four stages: (i) quasi-steady state effectively single-phase suspension flow down the wellbore, (ii) particle transport in an open vertical fracture, (iii) displacement of fracturing fluid by hydrocarbons from the closed fracture filled with a random close pack of proppant particles, and, finally, (iv) highly transient gas-liquid flow in a well during cleanup. The stage (i) is relatively well described by the existing hydralics models, while the models for the other three stages of the process need revisiting and considerable improvement, which was the focus of the author’s research presented in this review paper. For stage (ii), we consider the derivation of a multi-fluid model for suspension flow in a narrow vertical hydraulic fracture at moderate Re on the scale of fracture height and length and also the migration of particles across the flow on the scale of fracture width. At the stage of fracture cleanaup (iii), a novel multi-continua model for suspension filtration is developed. To provide closure relationships for permeability of proppant packings to be used in this model, a 3D direct numerical simulation of single phase flow is carried out using the lattice-Boltzmann method. For wellbore cleanup (iv), we present a combined 1D model for highly-transient gas-liquid flow based on the combination of multi-fluid and drift-flux approaches. The derivation of the drift-flux model from conservation olaws is criticall revisited in order to define the list of underlying assumptions and to mark the applicability margins of the model. All these fundamental problems share the same technological application (hydraulic fracturing) and the same method of research, namely, the multi-fluid approach to multiphase flow modeling and the consistent use of asymptotic methods. Multi-fluid models are then discussed in comparison with semi-empirical (often postulated) models widely used in the industry.

Femur loading in feet-first fall experiments using an anthropomorphic test device.

PubMed

Thompson, Angela; Bertocci, Gina; Smalley, Craig

2018-03-31

Femur fractures are a common orthopedic injury in young children. Falls account for a large portion of accidental femur fractures in young children, but there is also a high prevalence of femur fractures in child abuse, with falls often provided as false histories. Objective information regarding fracture potential in short distance fall scenarios may aid in assessing whether a child's injuries are the result of abuse or an accidental fall. Knowledge of femur loading is the first step towards understanding likelihood of fracture in a fall. Characterize femur loading during feet-first free falls using a surrogate representing a 12-month-old child. The femur and hip joint of a surrogate representing a 12-month-old were modified to improve biofidelity and measure femur loading; 6-axis load cells were integrated into the proximal and distal femur. Femur modification was based upon CT imaging of cadaveric femurs in children 10-14 months of age. Using the modified 12-month-old surrogate, feet-first free falls from 69 cm and 119 cm heights onto padded carpet and linoleum were conducted to assess fall dynamics and determine femur loading. Femur compression, bending moment, shear and torsional moment were measured for each fall. Fall dynamics differed across fall heights, but did not substantially differ by impact surface type. Significant differences were found in all loading conditions across fall heights, while only compression and bending loads differed between carpet and linoleum surfaces. Maximum compression, bending, torsion and shear occurred in 119 cm falls and were 572 N, 23 N-m, 11 N-m and 281 N, respectively. Fall dynamics play an important role in the biomechanical assessment of falls. Fall height was found to influence both fall dynamics and femur loading, while impact surface affected only compression and bending in feet-first falls; fall dynamics did not differ across carpet and linoleum. Improved pediatric thresholds are necessary to predict likelihood of fracture, but morphologically accurate representation of the lower extremity, along with accurate characterization of loading in falls are a crucial first step. Copyright © 2018 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Mesoscopic Length Scale Controls the Rheology of Dense Suspensions

NASA Astrophysics Data System (ADS)

Bonnoit, Claire; Lanuza, Jose; Lindner, Anke; Clement, Eric

2010-09-01

From the flow properties of dense granular suspensions on an inclined plane, we identify a mesoscopic length scale strongly increasing with volume fraction. When the flowing layer height is larger than this length scale, a diverging Newtonian viscosity is determined. However, when the flowing layer height drops below this scale, we evidence a nonlocal effective viscosity, decreasing as a power law of the flow height. We establish a scaling relation between this mesoscopic length scale and the suspension viscosity. These results support recent theoretical and numerical results implying collective and clustered granular motion when the jamming point is approached from below.

Mesoscopic length scale controls the rheology of dense suspensions.

PubMed

Bonnoit, Claire; Lanuza, Jose; Lindner, Anke; Clement, Eric

2010-09-03

From the flow properties of dense granular suspensions on an inclined plane, we identify a mesoscopic length scale strongly increasing with volume fraction. When the flowing layer height is larger than this length scale, a diverging Newtonian viscosity is determined. However, when the flowing layer height drops below this scale, we evidence a nonlocal effective viscosity, decreasing as a power law of the flow height. We establish a scaling relation between this mesoscopic length scale and the suspension viscosity. These results support recent theoretical and numerical results implying collective and clustered granular motion when the jamming point is approached from below.

Mixed-mode stress intensity factors for kink cracks with finite kink length loaded in tension and bending: application to dentin and enamel.

PubMed

Bechtle, Sabine; Fett, Theo; Rizzi, Gabriele; Habelitz, Stefan; Schneider, Gerold A

2010-05-01

Fracture toughness resistance curves describe a material's resistance against crack propagation. These curves are often used to characterize biomaterials like bone, nacre or dentin as these materials commonly exhibit a pronounced increase in fracture toughness with crack extension due to co-acting mechanisms such as crack bridging, crack deflection and microcracking. The knowledge of appropriate stress intensity factors which depend on the sample and crack geometry is essential for determining these curves. For the dental biomaterials enamel and dentin it was observed that, under bending and tensile loading, crack propagation occurs under certain constant angles to the initial notch direction during testing procedures used for fracture resistance curve determination. For this special crack geometry (a kink crack of finite length in a finite body) appropriate geometric function solutions are missing. Hence, we present in this study new mixed-mode stress intensity factors for kink cracks with finite kink length within samples of finite dimensions for two loading cases (tension and bending) which were derived from a combination of mixed-mode stress intensity factors of kink cracks with infinitely small kinks and of slant cracks. These results were further applied to determine the fracture resistance curves of enamel and dentin by testing single edge notched bending (SENB) specimens. It was found that kink cracks with finite kink length exhibit identical stress fields to slant cracks as soon as the kink length exceeds 0.15 times the initial straight crack or notch length. The use of stress intensity factor solutions for infinitely small kink cracks for the determination of dentin fracture resistance curves (as was done by other researchers) leads to an overestimation of dentin's fracture resistance of up to 30%. Copyright 2010 Elsevier Ltd. All rights reserved.

Evaluation of skeletal and dental age using third molar calcification, condylar height and length of the mandibular body.

PubMed

Kedarisetty, Sunil Gupta; Rao, Guttikonda Venkateswara; Rayapudi, Naveen; Korlepara, Rajani

2015-01-01

To identify the most reliable method for age estimation among three variables, that is, condylar height, length of mandibular body and third molar calcification by Demirjian's method. Orthopantomograms and lateral cephalograms of 60 patients with equal gender ratio were included in the study, among each gender 15 subjects were below 18 years and 15 subjects were above 18 years. Lateral cephalograms were traced, height of condyle and mandibular body are measured manually on the tracing paper, OPG's were observed on radiographic illuminator and maturity score of third molar calcification was noted according to Demirjian's method. All the measurements were subjected to statistical analysis. The results obtained are of no significant difference between estimated age and actual age with all three parameters (P > 0.9780 condylar height, P > 0.9515 length of mandibular body, P > 0.8611 third molar calcification). Among these three, length of mandibular body shows least standard error test (i.e. 0.188). Although all three parameters can be used for age estimation, length of mandibular body is more reliable followed by height of condyle and third molar calcification.

Treatment of fractures of the condylar head with resorbable pins or titanium screws: an experimental study.

PubMed

Schneider, Matthias; Loukota, Richard; Kuchta, Anne; Stadlinger, Bernd; Jung, Roland; Speckl, Katrin; Schmiedekampf, Robert; Eckelt, Uwe

2013-07-01

We aimed to compare in vivo the stability of fixation of condylar fractures in sheep using sonic bone welding and standard titanium screws. We assessed stability of the osteosynthesis and maintenance of the height of the mandibular ramus. Height decreased slightly in both groups compared with the opposite side. The volume of the condyle increased considerably in both groups mainly because callus had formed. The results showed no significant disadvantages for pin fixation compared with osteosynthesis using titanium screws. Copyright © 2012 The British Association of Oral and Maxillofacial Surgeons. All rights reserved.

Can we predict body height from segmental bone length measurements? A study of 3,647 children.

PubMed

Cheng, J C; Leung, S S; Chiu, B S; Tse, P W; Lee, C W; Chan, A K; Xia, G; Leung, A K; Xu, Y Y

1998-01-01

It is well known that significant differences exist in the anthropometric data of different races and ethnic groups. This is a cross-sectional study on segmental bone length based on 3,647 Chinese children of equal sex distribution aged 3-18 years. The measurements included standing height, weight, arm span, foot length, and segmental bone length of the humerus, radius, ulna, and tibia. A normality growth chart of all the measured parameters was constructed. Statistical analysis of the results showed a very high linear correlation of height with arm span, foot length, and segmental bone lengths with a correlation coefficient of 0.96-0.99 for both sexes. No differences were found between the right and left side of all the segmental bone lengths. These Chinese children were found to have a proportional limb segmental length relative to the trunk.

The Effect of Contact Area on the Fluid Flow-Fracture Specific Stiffness Relationship

NASA Astrophysics Data System (ADS)

Petrovitch, C.; Pyrak-Nolte, L. J.; Nolte, D. D.

2009-12-01

The integrity of subsurface CO2 sequestration sites can be compromised by the presence of mechanical discontinuities such as fractures, joints and faults. The ability to detect, seismically, and determine whether a discontinuity poses a risk, requires an understanding of the interrelationships among the mechanical, hydraulic and seismic properties of fractures rock. We performed a computational study to investigate the effect of fracture geometry on the relationship between fluid flow and fracture specific stiffness. The form of this relationship and the ability to scale it among different sample sizes provides a key link between the hydraulic and seismic response of fractures. In this study, model fracture topologies were simulated using the stratified continuum percolation method. This method constructs a hierarchical aperture distribution with a tunable spatial correlation length. Fractures with correlated and uncorrelated aperture distributions were used. The contact area across the fracture plane ranged from approximately 5% to 40%. The fracture specific stiffness was calculated by deforming each fracture numerically under a normal load and extracting the stiffness from the displacement-stress curves. Single-phase flow was calculated for each increment of stress by modeling the fracture topology as a network of elliptical pipes and solving the corresponding linear system of equations. We analyzed the relationship between fracture displacement and contact area and found that the correlation length associated with the contact area distribution enables a scaling relationship between displacement and contact area. The collapse of the fluid flow - stress relationship required use of standard percolation functional forms that use average aperture (cubic law), the void area fraction, and the correlation length of the contact area clusters. A final scaling relationship between fluid flow and fracture specific was found for the class of correlated fractures while a separate relationship was found for the uncorrelated fractures. By expanding the scaling parameters to include additional length scales, it may be possible to unify all of the flow-stiffness relationships, independent of geometry. Acknowledgments: The authors wish to acknowledge support of this work by the Geosciences Research Program, Office of Basic Energy Sciences US Department of Energy (DEFG02-97ER14785 08), the GeoMathematical Imaging Group at Purdue University and from the Computer Research Institute At Purdue University.

Risk Factors for Hip Fracture in Older Men: The Osteoporotic Fractures in Men Study (MrOS)

PubMed Central

Cauley, Jane A; Cawthon, Peggy M; Peters, Katherine E; Cummings, Steven R; Ensrud, Kristine E; Bauer, Douglas C; Taylor, Brent C; Shikany, James M; Hoffman, Andrew R; Lane, Nancy E; Kado, Deborah M; Stefanick, Marcia L; Orwoll, Eric S

2017-01-01

Almost 30% of hip fractures occur in men; the mortality, morbidity, and loss of independence after hip fractures are greater in men than in women. To comprehensively evaluate risk factors for hip fracture in older men, we performed a prospective study of 5994 men, primarily white, age 65+ years recruited at six US clinical centers. During a mean of 8.6 years of 97% complete follow-up, 178 men experienced incident hip fractures. Information on risk factors including femoral neck bone mineral density (FNBMD) was obtained at the baseline visit. Cox proportional hazards models were used to calculate the hazard ratio (HR) with 95% confidence intervals; Fine and Gray models adjusted for competing mortality risk. Older age (≥75 years), low FNBMD, currently smoking, greater height and height loss since age 25 years, history of fracture, use of tricyclic antidepressants, history of myocardial infarction or angina, hyperthyroidism or Parkinson’s disease, lower protein intake, and lower executive function were all associated with an increased hip fracture risk. Further adjustment for competing mortality attenuated HR for smoking, hyperthyroidism, and Parkinson’s disease. The incidence rate of hip fracture per 1000 person-years (PY) was greatest in men with FNBMD T-scores <−2.5 (white women reference database) who also had 4+ risk factors, 33.4. Men age ≥80 years with 3+ major comorbidities experienced hip fracture at rates of 14.52 versus 0.88 per 1000 PY in men age <70 years with zero comorbidities. Older men with low FNBMD, multiple risk factors, and multimorbidity have a high risk of hip fracture. Many of these assessments can easily be incorporated into routine clinical practice and may lead to improved risk stratification. PMID:26988112

Prevalence of vertebral fracture in Asian men and women: comparison between Hong Kong, Thailand, Indonesia and Japan.

PubMed

Kwok, A W L; Leung, J C S; Chan, A Y H; Au, B S K; Lau, E M C; Yurianto, H; Yuktanandana, P; Yoshimura, N; Muraki, S; Oka, H; Akune, T; Leung, P C

2012-06-01

Little is known about the prevalence of vertebral fracture among Asians. This study investigated the prevalence of radiographically defined vertebral fracture, and identified associated risk factors in the aged population of four Asian countries. In total, 1588 males and females aged ≥ 65 years were recruited from Hong Kong, Thailand, Indonesia and Japan. Standard X-rays for the spine were taken and vertebral heights were measured. Vertebral fracture was defined as a reduction of >3 standard deviations in vertebral height ratio. Bone mineral density (BMD) of the hip was measured by dual energy X-ray absorptiometry, and anthropometric measurements were taken in Hong Kong and Japan. Other relevant data were entered in a standard questionnaire. The prevalence of vertebral fracture for both males and females was highest in Japan for younger (65-74 years) and older (≥ 75 years) age groups (36.6% and 37.6% for males; 18.8% and 28.7% for females). Lower hip BMD was associated with vertebral fracture in both sexes. Older age, lower quality of life score on Short Form-12 (physical), past longest occupation as a farmer, and history of cataract were significantly associated with vertebral fracture in females. However, smoking did not appear to be an important risk factor for vertebral fracture. Radiographic assessments for vertebral fracture were performed in all four Asian countries. The prevalence of vertebral fracture was highest in Japan. Lower hip BMD, poorer physical condition and past longest occupation as a farmer were associated with vertebral fracture. Copyright © 2012 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Morphological characteristics of the posterior malleolar fragment according to ankle fracture patterns: a computed tomography-based study.

PubMed

Yi, Young; Chun, Dong-Il; Won, Sung Hun; Park, Suyeon; Lee, Sanghyeon; Cho, Jaeho

2018-02-13

The posterior malleolar fragment (PMF) of an ankle fracture can have various shapes depending on the injury mechanism. The purpose of this study was to evaluate the morphological characteristics of the PMF according to the ankle fracture pattern described in the Lauge-Hansen classification by using computed tomography (CT) images. We retrospectively analyzed CT data of 107 patients (107 ankles) who underwent surgery for trimalleolar fracture from January 2012 to December 2014. The patients were divided into two groups: 76 ankles in the supination-external rotation (SER) stage IV group and 31 ankles in the pronation-external rotation (PER) stage IV group. The PMF type of the two groups was assessed using the Haraguchi and Jan Bartonicek classification. The cross angle (α), fragment length ratio (FLR), fragment area ratio (FAR), sagittal angle (θ), and fragment height (FH) were measured to assess the morphological characteristics of the PMF. The PMF in the SER group mainly had a posterolateral shape, whereas that in the PER group mainly had a posteromedial two-part shape or a large posterolateral triangular shape (P = 0.02). The average cross angle was not significantly different between the two groups (SER group = 19.4°, PER group = 17.6°). The mean FLR and FH were significantly larger in the PER group than in the SER group (P = 0.024, P = 0.006). The mean fragment sagittal angle in the PER group was significantly smaller than that in the SER group (P = 0.017). With regard to the articular involvement, volume, and vertical nature, the SER-type fracture tends to have a smaller fragment due to the rotational force, whereas the PER-type fracture tends to have a larger fragment due to the combination of rotational and axial forces.

Roof Weakening of Hydraulic Fracturing for Control of Hanging Roof in the Face End of High Gassy Coal Longwall Mining: A Case Study

NASA Astrophysics Data System (ADS)

Huang, Bingxiang; Wang, Youzhuang

2016-09-01

The occurence of hanging roof commonly arises in the face end of longwall coal mining under hard roof conditions. The sudden break and subsequent caving of a hanging roof could result in the extrusion of gas in the gob to the face, causing gas concentrations to rise sharply and to increase to over a safety-limited value. A series of linear fracturing-holes of 32 mm diameter were drilled into the roof of the entries with an anchor rig. According to the theory that the gob should be fully filled with the fragmentized falling roof rock, the drilling depth is determined as being 3 5 times the mining height if the broken expansion coefficient takes an empirical value. Considering the general extension range of cracks and the supporting form of the entryway, the spacing distance between two drilling holes is determined as being 1 2 times the crack's range of extension. Using a mounting pipe, a high pressure resistant sealing device of a small diameter-size was sent to the designated location for the high-pressure hydraulic fracturing of the roof rock. The hydraulic fracturing created the main hydro-fracturing crack and airfoil branch cracks in the interior of the roof-rock, transforming the roof structure and weakening the strength of the roof to form a weak plane which accelerated roof caving, and eventually induced the full caving in of the roof in time with the help of ground pressure. For holes deeper than 4 m, retreating hydraulic fracturing could ensure the uniformity of crack extension. Tested and applied at several mines in Shengdong Mining District, the highest ruptured water pressure was found to be 55 MPa, and the hanging roof at the face end was reduced in length from 12 m to less than 1 2 m. This technology has eliminated the risk of the extrusion of gas which has accumulated in the gob.

OC30 - Fracture reduction with nitrous oxide at the children's emergency department shortens the length of stay and reduces the use of full anaesthesia in the operating department.

PubMed

Lang, Sigrid; Wentzel, Anna-Pia; Ekstrom, Malin

2016-05-09

Theme: Accreditation and quality improvement. Dislocated fractures are common in the children's emergency department (ER). All forms of fracture reduction are very painful requiring nitrous oxide. The purpose is to shorten the length of stay in the hospital as well as sustain a high quality of care. All nurses received theoretical and practical training in the use of nitrous oxide. Evaluations with the families were made by telephone. A total of 40 enclosed fracture reductions were made at the ER, leading to a reduction of 33 patients in the operating department and the length of stay was shortened - this compared to the same time in 2014. No adverse event was reported and no patient felt any increase in pain during the treatment. All patients would repeat the procedure if necessary. The treatment has reduced the length of stay in the hospital without affecting the other patients in the ER or the quality of care.

Effect of ferrule on the fracture resistance of mandibular premolars with prefabricated posts and cores

PubMed Central

2017-01-01

PURPOSE This study evaluated fracture resistance with regard to ferrule lengths and post reinforcement on endodontically treated mandibular premolars incorporating a prefabricated post and resin core. MATERIALS AND METHODS One hundred extracted mandibular premolars were randomly divided into 5 groups (n=20): intact teeth (NR); endodontically treated teeth (ETT) without post (NP); ETT restored with a prefabricated post with ferrule lengths of either 0 mm (F0), 1 mm (F1), or 2 mm (F2). Prepared teeth were restored with metal crowns. A thermal cycling test was performed for 1,000 cycles. Loading was applied at an angle of 135 degrees to the axis of the tooth using a universal testing machine with a crosshead speed of 2.54 mm/min. Fracture loads were analyzed by one-way ANOVA and Tukey HSD test using a statistical program (α=.05). RESULTS There were statistical differences in fracture loads among groups (P<.001). The fracture load of F2 (237.7 ± 83.4) was significantly higher than those of NP (155.6 ± 74.3 N), F0 (98.8 ± 43.3 N), and F1 (152.8 ± 78.5 N) (P=.011, P<.001, and P=.008, respectively). CONCLUSION Fracture resistance of ETT depends on the length of the ferrule, as shown by the significantly increased fracture resistance in the 2 mm ferrule group (F2) compared to the groups with shorter ferrule lengths (F0, F1) and without post (NP). PMID:29142639

Drainage fracture networks in elastic solids with internal fluid generation

NASA Astrophysics Data System (ADS)

Kobchenko, Maya; Hafver, Andreas; Jettestuen, Espen; Galland, Olivier; Renard, François; Meakin, Paul; Jamtveit, Bjørn; Dysthe, Dag K.

2013-06-01

Experiments in which CO2 gas was generated by the yeast fermentation of sugar in an elastic layer of gelatine gel confined between two glass plates are described and analyzed theoretically. The CO2 gas pressure causes the gel layer to fracture. The gas produced is drained on short length scales by diffusion and on long length scales by flow in a fracture network, which has topological properties that are intermediate between river networks and hierarchical-fracture networks. A simple model for the experimental system with two parameters that characterize the disorder and the intermediate (river-fracture) topology of the network was developed and the results of the model were compared with the experimental results.

Whom to treat? The contribution of vertebral X-rays to risk-based algorithms for fracture prediction. Results from the European Prospective Osteoporosis Study.

PubMed

Kaptoge, S; Armbrecht, G; Felsenberg, D; Lunt, M; Weber, K; Boonen, S; Jajic, I; Stepan, J J; Banzer, D; Reisinger, W; Janott, J; Kragl, G; Scheidt-Nave, C; Felsch, B; Matthis, C; Raspe, H H; Lyritis, G; Póor, G; Nuti, R; Miazgowski, T; Hoszowski, K; Armas, J Bruges; Vaz, A Lopes; Benevolenskaya, L I; Masaryk, P; Cannata, J B; Johnell, O; Reid, D M; Bhalla, A; Woolf, A D; Todd, C J; Cooper, C; Eastell, R; Kanis, J A; O'Neill, T W; Silman, A J; Reeve, J

2006-01-01

Vertebral fracture is a strong risk factor for future spine and hip fractures; yet recent data suggest that only 5-20% of subjects with a spine fracture are identified in primary care. We aimed to develop easily applicable algorithms predicting a high risk of future spine fracture in men and women over 50 years of age. Data was analysed from 5,561 men and women aged 50+ years participating in the European Prospective Osteoporosis Study (EPOS). Lateral thoracic and lumbar spine radiographs were taken at baseline and at an average of 3.8 years later. These were evaluated by an experienced radiologist. The risk of a new (incident) vertebral fracture was modelled as a function of age, number of prevalent vertebral fractures, height loss, sex and other fracture history reported by the subject, including limb fractures occurring between X-rays. Receiver Operating Characteristic (ROC) curves were used to compare the predictive ability of models. In a negative binomial regression model without baseline X-ray data, the risk of incident vertebral fracture significantly increased with age [RR 1.74, 95% CI (1.44, 2.10) per decade], height loss [1.08 (1.04, 1.12) per cm decrease], female sex [1.48 (1.05, 2.09)], and recalled fracture history; [1.65 (1.15, 2.38) to 3.03 (1.66, 5.54)] according to fracture site. Baseline radiological assessment of prevalent vertebral fracture significantly improved the areas subtended by ROC curves from 0.71 (0.67, 0.74) to 0.74 (0.70, 0.77) P=0.013 for predicting 1+ incident fracture; and from 0.74 (0.67, 0.81) to 0.83 (0.76, 0.90) P=0.001 for 2+ incident fractures. Age, sex and height loss remained independently predictive. The relative risk of a new vertebral fracture increased with the number of prevalent vertebral fractures present from 3.08 (2.10, 4.52) for 1 fracture to 9.36 (5.72, 15.32) for 3+. At a specificity of 90%, the model including X-ray data improved the sensitivity for predicting 2+ and 1+ incident fractures by 6 and 4 fold respectively compared with random guessing. At 75% specificity the improvements were 3.2 and 2.4 fold respectively. With the modelling restricted to the subjects who had BMD measurements (n=2,409), the AUC for predicting 1+ vs. 0 incident vertebral fractures improved from 0.72 (0.66, 0.79) to 0.76 (0.71, 0.82) upon adding femoral neck BMD (P=0.010). We conclude that for those with existing vertebral fractures, an accurately read spine X-ray will form a central component in future algorithms for targeting treatment, especially to the most vulnerable. The sensitivity of this approach to identifying vertebral fracture cases requiring anti-osteoporosis treatment, even when X-rays are ordered highly selectively, exceeds by a large margin the current standard of practice as recorded anywhere in the world.

Head and neck injury patterns in fatal falls: epidemiologic and biomechanical considerations.

PubMed

Freeman, Michael D; Eriksson, Anders; Leith, Wendy

2014-01-01

Fatal falls often involve a head impact, which are in turn associated with a fracture of the skull or cervical spine. Prior authors have noted that the degree of inversion of the victim at the time of impact is an important predictor of the distribution of skull fractures, with skull base fractures more common than skull vault fractures in falls with a high degree of inversion. The majority of fatal fall publications have focused on skull fractures, and no research has described the association between fall circumstances and the distribution of fractures in the skull and neck. In the present study, we accessed data regarding head and neck fractures resulting from fatal falls from a Swedish autopsy database for the years 1992-2010, for the purposes of examining the relationships between skull and cervical spine fracture distribution and the circumstances of the fatal fall. Out of 102,310 medico-legal autopsies performed there were 1008 cases of falls associated with skull or cervical spine fractures. The circumstances of the falls were grouped in 3 statistically homogenous categories; falls occurring at ground level, falls from a height of <3 m or down stairs, and falls from ≥3 m. Only head and neck injuries and fractures that were associated with the fatal CNS injuries were included for study, and categorized as skull vault and skull base fractures, upper cervical injuries (C0-C1 dislocation, C1 and C2 fractures), and lower cervical fractures. Logistic regression modeling revealed increased odds of skull base and lower cervical fracture in the middle and upper fall severity groups, relative to ground level falls (lower cervical <3 m falls, OR = 2.55 [1.32, 4.92]; lower cervical ≥3 m falls, OR = 2.23 [0.98, 5.08]; skull base <3 m falls, OR = 1.82 [1.32, 2.50]; skull base ≥3 m falls, OR = 2.30 [1.55, 3.40]). C0-C1 dislocations were strongly related to fall height, with an OR of 8.3 for ≥3 m falls versus ground level. The findings of increased odds of skull base and lower cervical spine fracture in falls from a height are consistent with prior observations that the risk of such injuries is related to the degree of victim inversion at impact. The finding that C0-C1 dislocations are most common in falls from more than 3 m is unique, an indication that the injuries likely result from high energy shear forces rather than pure tension, as previously thought. Copyright © 2013 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Bone fractures following external beam radiotherapy and limb-preservation surgery for lower extremity soft tissue sarcoma: relationship to irradiated bone length, volume, tumor location and dose.

PubMed

Dickie, Colleen I; Parent, Amy L; Griffin, Anthony M; Fung, Sharon; Chung, Peter W M; Catton, Charles N; Ferguson, Peter C; Wunder, Jay S; Bell, Robert S; Sharpe, Michael B; O'Sullivan, Brian

2009-11-15

To examine the relationship between tumor location, bone dose, and irradiated bone length on the development of radiation-induced fractures for lower extremity soft tissue sarcoma (LE-STS) patients treated with limb-sparing surgery and radiotherapy (RT). Of 691 LE-STS patients treated from 1989 to 2005, 31 patients developed radiation-induced fractures. Analysis was limited to 21 fracture patients (24 fractures) who were matched based on tumor size and location, age, beam arrangement, and mean total cumulative RT dose to a random sample of 53 nonfracture patients and compared for fracture risk factors. Mean dose to bone, RT field size (FS), maximum dose to a 2-cc volume of bone, and volume of bone irradiated to >or=40 Gy (V40) were compared. Fracture site dose was determined by comparing radiographic images and surgical reports to fracture location on the dose distribution. For fracture patients, mean dose to bone was 45 +/- 8 Gy (mean dose at fracture site 59 +/- 7 Gy), mean FS was 37 +/- 8 cm, maximum dose was 64 +/- 7 Gy, and V40 was 76 +/- 17%, compared with 37 +/- 11 Gy, 32 +/- 9 cm, 59 +/- 8 Gy, and 64 +/- 22% for nonfracture patients. Differences in mean, maximum dose, and V40 were statistically significant (p = 0.01, p = 0.02, p = 0.01). Leg fractures were more common above the knee joint. The risk of radiation-induced fracture appears to be reduced if V40 <64%. Fracture incidence was lower when the mean dose to bone was <37 Gy or maximum dose anywhere along the length of bone was <59 Gy. There was a trend toward lower mean FS for nonfracture patients.

Relationship between hamstring length and gluteus maximus strength with and without normalization.

PubMed

Lee, Dong-Kyu; Oh, Jae-Seop

2018-01-01

[Purpose] This study assessed the relationship between hamstring length and gluteus maximus (GM) strength with and without normalization by body weight and height. [Subjects and Methods] In total, 34 healthy male subjects volunteered for this study. To measure GM strength, subjects performed maximal hip joint extension with the knee joints flexed to 90° in the prone position. GM strength was normalized for body weight and height. [Results] GM strength with normalization was positively correlated with hamstring length, whereas GM strength without normalization was negatively correlated with hamstring length. [Conclusion] The normalization of GM strength by body weight and height has the potential to lead to more appropriate conclusions and interpretations about its correlation with hamstring length. Hamstring length may be related to GM strength.

Kyphoplasty increases vertebral height, decreases both pain score and opiate requirements while improving functional status.

PubMed

Tolba, Reda; Bolash, Robert B; Shroll, Joshua; Costandi, Shrif; Dalton, Jarrod E; Sanghvi, Chirag; Mekhail, Nagy

2014-03-01

Vertebral compression fractures can result from advanced osteoporosis, or less commonly from metastatic or traumatic insults to the vertebral column, and result in disabling pain and decreased functional capacity. Various vertebral augmentation options including kyphoplasty aim at preventing the sequelae of pain and immobility that can develop as the result of the vertebral fractures. The mechanism for pain relief following kyphoplasty is not entirely understood, and the restoration of a portion of the lost vertebral height is a subject of debate. We retrospectively reviewed radiographic imaging, pain relief, analgesic intake and functional outcomes in 67 consecutive patients who underwent single- or multilevel kyphoplasty with the primary goal of quantifying the restoration of lost vertebral height. We observed a mean of 45% of the lost vertebral height restored postprocedurally. Secondarily, kyphoplasty was associated with significant decreases in pain scores, daily morphine consumption and improvement in patient-reported functional measures. © 2013 World Institute of Pain.

Experimental Analysis of Hydraulic Fracture Growth and Acoustic Emission Response in a Layered Formation

NASA Astrophysics Data System (ADS)

Ning, Li; Shicheng, Zhang; Yushi, Zou; Xinfang, Ma; Shan, Wu; Yinuo, Zhang

2018-04-01

Microseismic/acoustic emission (AE) monitoring is an essential technology for understanding hydraulic fracture (HF) geometry and stimulated reservoir volume (SRV) during hydraulic fracturing in unconventional reservoirs. To investigate HF growth mechanisms and features of induced microseismic/AE events in a layered formation, laboratory fracturing experiments were performed on shale specimens (30 cm × 30 cm × 30 cm) with multiple bedding planes (BPs) under triaxial stresses. AE monitoring was used to reveal the spatial distribution and hypocenter mechanisms of AE events induced by rock failure. Computerized tomography scanning was used to observe the internal fracture geometry. Experimental results showed that the various HF geometries could be obviously distinguished based on injection pressure curves and AE responses. Fracture complexity was notably increased when vertically growing HFs connected with and opened more BPs. The formation of a complex fracture network was generally indicated by frequent fluctuations in injection pressure curves, intense AE activity, and three-dimensionally distributed AE events. Investigations of the hypocenter mechanisms revealed that shear failure/event dominated in shale specimens. Shear and tensile events were induced in hydraulically connected regions, and shear events also occurred around BPs that were not hydraulically connected. This led to an overestimation of HF height and SRV in layered formations based on the AE location results. The results also showed that variable injection rate and using plugging agent were conducive in promoting HF to penetrate through the weak and high-permeability BPs, thereby increasing the fracture height.

Incorporating Scale-Dependent Fracture Stiffness for Improved Reservoir Performance Prediction

NASA Astrophysics Data System (ADS)

Crawford, B. R.; Tsenn, M. C.; Homburg, J. M.; Stehle, R. C.; Freysteinson, J. A.; Reese, W. C.

2017-12-01

We present a novel technique for predicting dynamic fracture network response to production-driven changes in effective stress, with the potential for optimizing depletion planning and improving recovery prediction in stress-sensitive naturally fractured reservoirs. A key component of the method involves laboratory geomechanics testing of single fractures in order to develop a unique scaling relationship between fracture normal stiffness and initial mechanical aperture. Details of the workflow are as follows: tensile, opening mode fractures are created in a variety of low matrix permeability rocks with initial, unstressed apertures in the micrometer to millimeter range, as determined from image analyses of X-ray CT scans; subsequent hydrostatic compression of these fractured samples with synchronous radial strain and flow measurement indicates that both mechanical and hydraulic aperture reduction varies linearly with the natural logarithm of effective normal stress; these stress-sensitive single-fracture laboratory observations are then upscaled to networks with fracture populations displaying frequency-length and length-aperture scaling laws commonly exhibited by natural fracture arrays; functional relationships between reservoir pressure reduction and fracture network porosity, compressibility and directional permeabilities as generated by such discrete fracture network modeling are then exported to the reservoir simulator for improved naturally fractured reservoir performance prediction.

Safe Zone of Posterior Screw Insertion for Talar Neck Fractures on 3-Dimensional Reconstruction Model.

PubMed

Wu, Jian-Qun; Ma, Sheng-Hui; Liu, Song; Qin, Cheng-He; Jin, Dan; Yu, Bin

2017-02-01

To investigate the optimal posterior screw placement and the geometry of safe zones for screw insertion in the talar neck. Computed tomography data for 15 normal feet were imported into Mimics 10.01 software for 3-dimensional reconstruction; 4.0-mm-diameter screws were simulated from the lateral tubercle of the posterior process of the talus to the talar head. The range of screw paths trajectories and screw lengths at nine locations that did not breach the cortex of the talus were evaluated. In addition, the farthest (point a) and nearest point (point b) of the safe zone to the subtalar joint at each location, the anteversion angle (angle A), which is parallel to the sagittal plane, and the horizontal angle (angle B), which is perpendicular to the sagittal plane, were measured. The safe zone was mainly between the 30% location and the 60% location; the width of each safe zone was 13.6° ± 1.4°; the maximum height of each safe zone was 7.8° ± 1.2°. The height of the safe zone was lowest at the 30% location (4.5°) and highest at the 50% location (7.3°). The mixed safe zone of all tali was between the 50% location and the 60% location. When a screw was inserted at point a, the safe entry distance (screw length) ranged from 48.8 to 49.5 mm, and when inserted to point b, the distance ranged from 48.2 to 48.9 mm. And inserting a 48.7 mm screw, 5.6° laterally and 7.4° superiorly, from the lateral tubercle of the posterior process of the talus towards the talar head is safest. The safe zone of posterior screw fixation have been defined applying to most talus, assuming the fractures are well reduced, this may strengthen the stability, shorten the operation time and reduce the incidence of surgical complications. © 2017 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

Fracture Strength of Three-Unit Implant Supported Fixed Partial Dentures with Excessive Crown Height Fabricated from Different Materials.

PubMed

Nazari, Vahideh; Ghodsi, Safoura; Alikhasi, Marzieh; Sahebi, Majid; Shamshiri, Ahmad Reza

2016-11-01

Fracture strength is an important factor influencing the clinical long-term success of implant-supported prostheses especially in high stress situations like excessive crown height space (CHS). The purpose of this study was to compare the fracture strength of implant-supported fixed partial dentures (FPDs) with excessive crown height, fabricated from three different materials. Two implants with corresponding abutments were mounted in a metal model that simulated mandibular second premolar and second molar. Thirty 3-unit frameworks with supportive anatomical design were fabricated using zirconia, nickel-chromium alloy (Ni-Cr), and polyetheretherketone (PEEK) (n=10). After veneering, the CHS was equal to 15mm. Then; samples were axially loaded on the center of pontics until fracture in a universal testing machine at a crosshead speed of 0.5 mm/minute. The failure load data were analyzed by one-way ANOVA and Games-Howell tests at significance level of 0.05. The mean failure loads for zirconia, Ni-Cr and PEEK restorations were 2086±362N, 5591±1200N and 1430±262N, respectively. There were significant differences in the mean failure loads of the three groups (P<0.001). The fracture modes in zirconia, metal ceramic and PEEK restorations were cohesive, mixed and adhesive type, respectively. According to the findings of this study, all implant supported three-unit FPDs fabricated of zirconia, metal ceramic and PEEK materials are capable to withstand bite force (even para-functions) in the molar region with excessive CHS.

Height and relative leg length as indicators of the quality of the environment among Mozambican juveniles and adolescents.

PubMed

Padez, Cristina; Varela-Silva, Maria Inês; Bogin, Barry

2009-01-01

The growth status of Mozambique adolescents was assessed to test the hypothesis that relative leg length is a more sensitive indicator of the quality of the environment than the total height. The sample comprised 690 boys and 727 girls, aged between 9 and 17 years, from Maputo. It is divided between those living in the Centre of Maputo and those living in the slums on the periphery of the city. Height, weight, and sitting height were measured and the sitting height ratio was calculated. The hypothesis that relative leg length is more sensitive than total stature as an indicator of environmental quality is not uniformly confirmed. Overall, mean stature is greater for the centre group than the slum group, but relative leg length as measured by the sitting height ratio does not differ. Compared with African-American references (NHANES II), all centre girls, 9- to 14-year-old slum girls, all slum boys, and the oldest centre boys show relatively shorter legs. These findings show that within the Mozambique sample, relative leg length is not sensitive enough to distinguish the quality of the living environment. Mozambique was a colony of Portugal until 1975. Civil unrest and warfare characterized the late Colonial period and the postindependence period until a peace settlement was concluded in 1992. It is possible that all socioeconomic status groups within the country suffered sufficiently to reduce relative leg length compared with the better-off African-American reference sample. Possible genetic influences on relative leg length are also discussed.

Hip fracture in hospitalized medical patients.

PubMed

Zapatero, Antonio; Barba, Raquel; Canora, Jesús; Losa, Juan E; Plaza, Susana; San Roman, Jesús; Marco, Javier

2013-01-08

The aim of the present study is to analyze the incidence of hip fracture as a complication of admissions to internal medicine units in Spain. We analyzed the clinical data of 2,134,363 adults who had been admitted to internal medicine wards. The main outcome was a diagnosis of hip fracture during hospitalization.Outcome measures included rates of in-hospital fractures, length of stay and cost. A total of 1127 (0.057%) admittances were coded with an in-hospital hip fracture. In hospital mortality rate was 27.9% vs 9.4%; p < 0.001, and the mean length of stay was significantly longer for patients with a hip fracture (20.7 days vs 9.8 days; p < 0.001). Cost were higher in hip-fracture patients (6927€ per hospitalization vs 3730€ in non fracture patients). Risk factors related to fracture were: increasing age by 10 years increments (OR 2.32 95% CI 2.11-2.56), female gender (OR 1.22 95% CI 1.08-1.37), admission from nursing home (OR 1.65 95% CI 1.27-2.12), dementia (1.55 OR 95% CI1.30-1.84), malnutrition (OR 2.50 95% CI 1.88-3.32), delirium (OR 1.57 95% CI 1.16-2.14), and anemia (OR 1.30 95%CI 1.12-1.49). In-hospital hip fracture notably increased mortality during hospitalization, doubling the mean length of stay and mean cost of admission. These are reasons enough to stress the importance of designing and applying multidisciplinary plans focused on reducing the incidence of hip fractures in hospitalized patients.

Genome-wide Analysis of Body Proportion Classifies Height-Associated Variants by Mechanism of Action and Implicates Genes Important for Skeletal Development

PubMed Central

Chan, Yingleong; Salem, Rany M.; Hsu, Yu-Han H.; McMahon, George; Pers, Tune H.; Vedantam, Sailaja; Esko, Tonu; Guo, Michael H.; Lim, Elaine T.; Franke, Lude; Smith, George Davey; Strachan, David P.; Hirschhorn, Joel N.

2015-01-01

Human height is a composite measurement, reflecting the sum of leg, spine, and head lengths. Many common variants influence total height, but the effects of these or other variants on the components of height (body proportion) remain largely unknown. We studied sitting height ratio (SHR), the ratio of sitting height to total height, to identify such effects in 3,545 African Americans and 21,590 individuals of European ancestry. We found that SHR is heritable: 26% and 39% of the total variance of SHR can be explained by common variants in European and African Americans, respectively, and global European admixture is negatively correlated with SHR in African Americans (r2 ≈ 0.03). Six regions reached genome-wide significance (p < 5 × 10−8) for association with SHR and overlapped biological candidate genes, including TBX2 and IGFBP3. We found that 130 of 670 height-associated variants are nominally associated (p < 0.05) with SHR, more than expected by chance (p = 5 × 10−40). At these 130 loci, the height-increasing alleles are associated with either a decrease (71 loci) or increase (59 loci) in SHR, suggesting that different height loci disproportionally affect either leg length or spine/head length. Pathway analyses via DEPICT revealed that height loci affecting SHR, and especially those affecting leg length, show enrichment of different biological pathways (e.g., bone/cartilage/growth plate pathways) than do loci with no effect on SHR (e.g., embryonic development). These results highlight the value of using a pair of related but orthogonal phenotypes, in this case SHR with height, as a prism to dissect the biology underlying genetic associations in polygenic traits and diseases. PMID:25865494

Long bone robustness during growth: A cross-sectional pQCT examination of children and young adults aged 5-29years.

PubMed

Rantalainen, Timo; Weeks, Benjamin K; Nogueira, Rossana C; Beck, Belinda R

2016-12-01

Skeletal robustness (cross-section size relative to length) is associated with stress fractures in adults, and appears to explain the high incidence of distal radius fractures in adolescents. However, little is known about the ontogeny of long bone robustness during the first three decades of life. Therefore, we explored the ontogeny of tibial, fibular, ulnar and radial robustness in a cross-sectional sample of 5 to 29year-old volunteers of both sexes. Peripheral quantitative computed tomography (pQCT) was used to evaluate cross-sections of the leg (4%, 14%, 38% and 66%), and forearm (4%, and 66%) in N=432 individuals. Robustness was evaluated as the total bone area divided by bone length. Differences between age-groups, sexes, and age-group×sex interactions were evaluated with ANOVA with Tukey's post hocs where appropriate. Most bone sites exhibited more robust bones in men than women (P<0.001 to 0.02), and in older age-groups than younger (P<0.001). Sex×age-group interaction was observed at the 66% and 38% tibia sites with robustness increasing more with age in men than in women (P=0.006 to 0.042). Post-hoc analyses indicated no sex differences prior to 13years-of-age, and notable exceptions to increasing robustness with age at the 4% radial and 66% tibial sites, which exhibited reduced robustness in age groups close to peak height velocity. In conclusion, the present results suggest that very little sexual dimorphism in long bone robustness exists prior to puberty, and that divergence occurs primarily after cessation of longitudinal growth. A period of relative diaphyseal slenderness was identified at age-groups coinciding with the adolescent growth spurt, which may be related to the relatively high incidence of frank and stress fracture in adolescents. Copyright © 2016 Elsevier Inc. All rights reserved.

49 CFR 38.29 - Interior circulation, handrails and stanchions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... length with front-door lifts or ramps, vertical stanchions immediately behind the driver shall either... of 22 feet in length, the minimum interior height along the path from the lift to the securement location shall be 68 inches. For vehicles of 22 feet in length or less, the minimum interior height from...

The association between type of spine fracture and the mechanism of trauma: A useful tool for identifying mechanism of trauma on legal medicine field.

PubMed

Aghakhani, Kamran; Kordrostami, Roya; Memarian, Azadeh; Asl, Nahid Dadashzadeh; Zavareh, Fatemeh Noorian

2018-05-01

Determining the association between mechanism of trauma, and the type of spine column fracture is a useful approach for exactly describing spine injury on forensic medicine field. We aimed to determine mechanism of trauma based on distribution of the transition of spinal column fractures. This cross-sectional survey was performed on 117 consecutive patients with the history of spinal trauma who were admitted to emergency ward of Rasoul-e-Akram Hospital in Tehran, Iran from April 2015 to March 2016. The baseline characteristics were collected by reviewing the hospital recorded files. With respect to mechanism of fracture, 63.2% of fractures were caused by falling, 30.8% by collisions with motor vehicles, and others caused by the violence. Regarding site of fracture, lumbosacral was affected in 47.9%, thoracic in 29.9%, and cervical in 13.7%. Regarding type of fracture, burst fracture was the most common type (71.8%) followed by compressive fracture (14.5%). The site of fracture was specifically associated with the mechanism of injury; the most common injuries induced by falling from height were found in lumbosacral and cervical sites, and the most frequent injuries by traffic accidents were found in thoracic site; also the injuries following violence were observed more in lumbar vertebrae. The burst fractures were more revealed in the patients affected by falling from height and by traffic accidents, and both burst and compressive fractures were more observed with the same result in the patients injured with violence (p = 0.003). The type of spine fracture due to trauma is closely associated with the mechanism of trauma that can be helpful in legal medicine to identify the mechanism of trauma in affected patients. Copyright © 2018. Published by Elsevier Ltd.

Crown development in a pioneer tree, Rhus trichocarpa, in relation to the structure and growth of individual branches.

PubMed

Osada, Noriyuki

2006-01-01

Based on an allometric reconstruction, the structure and biomass-allocation patterns of branches and current-year shoots were investigated in branches of various heights in the pioneer tree Rhus trichocarpa, to evaluate how crown development is achieved and limited in association with height. Path analysis was conducted to explore the effects of light availability, basal height and size of individual branches on branch structure and growth. Branch angle was affected by basal height, whereas branch mass was influenced primarily by light availability. This result suggests that branch structure is strongly constrained by basal height, and that trees mediate such constraints under different light environments. Previous-year leaf area and light availability showed positive effects on current-year stem mass. In contrast, branch basal height and mass negatively affected current-year stem mass. Moreover, the length of stems of a given diameter decreased with increasing branch height. Therefore the cost of biomass investment for a unit growth in length is greater for branches of larger size and at upper positions. Vertical growth rate in length decreased with increasing height. Height-dependent changes in stem allometry and angle influenced the reduction in vertical growth rate to a similar degree.

Evaluation of skeletal and dental age using third molar calcification, condylar height and length of the mandibular body

PubMed Central

Kedarisetty, Sunil Gupta; Rao, Guttikonda Venkateswara; Rayapudi, Naveen; Korlepara, Rajani

2015-01-01

Aim: To identify the most reliable method for age estimation among three variables, that is, condylar height, length of mandibular body and third molar calcification by Demirjian's method. Materials and Methods: Orthopantomograms and lateral cephalograms of 60 patients with equal gender ratio were included in the study, among each gender 15 subjects were below 18 years and 15 subjects were above 18 years. Lateral cephalograms were traced, height of condyle and mandibular body are measured manually on the tracing paper, OPG's were observed on radiographic illuminator and maturity score of third molar calcification was noted according to Demirjian's method. All the measurements were subjected to statistical analysis. Results: The results obtained are of no significant difference between estimated age and actual age with all three parameters (P > 0.9780 condylar height, P > 0.9515 length of mandibular body, P > 0.8611 third molar calcification). Among these three, length of mandibular body shows least standard error test (i.e. 0.188). Conclusion: Although all three parameters can be used for age estimation, length of mandibular body is more reliable followed by height of condyle and third molar calcification. PMID:26005300

An anthropometric analysis of facial height, arch length, and palatal rugae in the Indian and Nepalese population.

PubMed

Kallianpur, Shreenivas; Desai, Ami; Kasetty, Sowmya; Sudheendra, Us; Joshi, Prathamesh

2011-01-01

A country such as India abounds with diverse population groups with distinct anthropometric characteristics. Among these, numerous Nepalese population groups are present in different states of India comprising one of the most common immigrant races. The aim of the study is to compare two distinct races, Indians and Nepalese on the basis of facial height proportions, arch length and palatal rugae patterns and assess their significance in racial identification. A total of 120 subjects comprising of 60 Indians and 60 Nepalese were selected, with each group including 30 males and 30 females. Facial heights were measured using sliding digital calipers, arch lengths with the help of a brass wire and rugae patterns were traced on dental casts obtained with alginate impressions. Facial height measurements did not give significant results for racial or gender identification of given races. Differences between arch length parameters were found to be significant between the two population groups. Secondary and fragmentary palatal rugae forms were found to be more common in Nepalese than Indians. The Indian and Nepalese have similar anthropometric characteristics with regard to facial height. However, arch length and palatal rugae characteristics vary between the two races.

Measurement of clavicular length and shortening after a midshaft clavicular fracture: Spatial digitization versus planar roentgen photogrammetry.

PubMed

Stegeman, Sylvia A; de Witte, Pieter Bas; Boonstra, Sjoerd; de Groot, Jurriaan H; Nagels, Jochem; Krijnen, Pieta; Schipper, Inger B

2016-08-01

Clavicular shortening after fracture is deemed prognostic for clinical outcome and is therefore generally assessed on radiographs. It is used for clinical decision making regarding operative or non-operative treatment in the first 2weeks after trauma, although the reliability and accuracy of the measurements are unclear. This study aimed to assess the reliability of roentgen photogrammetry (2D) of clavicular length and shortening, and to compare these with 3D-spatial digitization measurements, obtained with an electromagnetic recording system (Flock of Birds). Thirty-two participants with a consolidated non-operatively treated two or multi-fragmented dislocated midshaft clavicular fracture were analysed. Two observers measured clavicular lengths and absolute and proportional clavicular shortening on radiographs taken before and after fracture consolidation. The clavicular lengths were also measured with spatial digitization. Inter-observer agreement on the radiographic measurements was assessed using the Intraclass Correlation Coefficient (ICC). Agreement between the radiographic and spatial digitization measurements was assessed using a Bland-Altman plot. The inter-observer agreement on clavicular length, and absolute and proportional shortening on trauma radiographs was almost perfect (ICC>0.90), but moderate for absolute shortening after consolidation (ICC=0.45). The Bland-Altman plot compared measurements of length on AP panorama radiographs with spatial digitization and showed that planar roentgen photogrammetry resulted in up to 37mm longer and 34mm shorter measurements than spatial digitization. Measurements of clavicular length on radiographs are highly reliable between observers, but may not reflect the actual length and shortening of the clavicle when compared to length measurements with spatial digitization. We recommend to use proportional shortening when measuring clavicular length or shortening on radiographs for clinical decision making. Copyright © 2015 Elsevier Ltd. All rights reserved.

Vitamin D serum levels are associated with handgrip strength but not with muscle mass or length of hospital stay after hip fracture.

PubMed

Gumieiro, David Nicoletti; Murino Rafacho, Bruna Paola; Buzati Pereira, Bruna Letícia; Cavallari, Karelin Alvisi; Tanni, Suzana Erico; Azevedo, Paula Schmidt; Polegato, Bertha Furlan; Mamede Zornoff, Leonardo Antonio; Dinhane, Daniel Innocenti; Innocenti Dinhane, Kandir Genésio; Cação Pereira, Gilberto José; de Paiva, Sergio Alberto Rupp; Minicucci, Marcos Ferreira

2015-01-01

The aim of this study was to evaluate the association between serum levels of 25(OH) vitamin D3 with midupper arm muscle circumference (MUAMC), handgrip strength and length of hospital stay (LOS) after hip fracture. In total, 102 consecutive patients with hip fracture over the age of 65 were admitted to the orthopedic unit and prospectively evaluated. All of the patients were treated according to specific protocols depending on the type of fracture. Anthropometric measurements and handgrip strength were performed, and blood samples were taken for serum biochemistry and 25(OH) vitamin D3 analysis within the first 72 h of admission. All of the patients were followed during their hospital stay, and the length of stay was recorded. Of the patients, two were excluded because of pathologic fractures. In total, 100 patients with a mean age of 80 ± 7 y were included in the analysis. Among these patients, 73% were female, and 37% had vitamin D deficiency. The median LOS was 7 (5-11) d. Patients with vitamin D deficiency had lower handgrip strength in univariate analysis. In the multiple linear regression analysis with robust standard error, serum vitamin D levels adjusted by age and sex were associated with handgrip strength but not with MUAMC and LOS after hip fracture. In conclusion, vitamin D serum levels were associated with handgrip strength but not with muscle mass or length of hospital stay after hip fracture. Copyright © 2015 Elsevier Inc. All rights reserved.

Pressures in Tumuli: A Study of Tumuli Formation

NASA Technical Reports Server (NTRS)

Hansen, James E.

2005-01-01

Tumuli form via localized inflation in surface lava flows. These domed features have widths of 10-20 m, lengths of 10-150 m, and heights of 1-9 m. The axial fracture exposes a brittle crust overlying a ductilely deformed layer. The total crustal thickness is typically less than lm. Tumuli are observed on both terrestrial and martian lava flow surfaces, and provide insight on the flow formation processes and rates. Past studies have estimated the inflation pressure using a bending model for a circular, thin elastic plate, assuming small deflection (Rossi and Gudmundson, 1996). This formulation results in unrealistic pressures for some tumuli. We thus examine alternative models, including those with different shapes, bending of the ductile crust, large deflection, plastic deformation, and thick plate bending. Using the thickness of the ductile crust in the equations for thin, circular plates reduces most pressures to reasonable values. Alternative plate shapes do not cause a significant reduction in inflation pressure. Although the large deflection equations should be applicable based on the plate thickness to tumuli height ratios, they give even less realistic pressures. Tumuli with unrealistic pressures appear to have exceeded the critical bending moment, and have relatively thick crusts, requiring thick plate bending models.

Influence of Gender and Age on Upper-Airway Length During Development

PubMed Central

Ronen, Ohad; Malhotra, Atul; Pillar, Giora

2008-01-01

OBJECTIVE Obstructive sleep apnea has a strong male predominance in adults but not in children. The collapsible portion of the upper airway is longer in adult men than in women (a property that may increase vulnerability to collapse during sleep). We sought to test the hypothesis that in prepubertal children, pharyngeal airway length is equal between genders, but after puberty boys have a longer upper airway than girls, thus potentially contributing to this change in apnea propensity. METHODS Sixty-nine healthy boys and girls who had undergone computed tomography scans of their neck for other reasons were selected from the computed tomography archives of Rambam and Carmel hospitals. The airway length was measured in the midsagittal plane and defined as the length between the lower part of the posterior hard palate and the upper limit of the hyoid bone. Airway length and normalized airway length/body height were compared between the genders in prepubertal (4- to 10-year-old) and postpubertal (14- to 19-year-old) children. RESULTS In prepubertal children, airway length was similar between boys and girls (43.2 ± 5.9 vs 46.8 ± 7.7 mm, respectively). When normalized to body height, airway length/body height was significantly shorter in prepubertal boys than in girls (0.35 ± 0.03 vs 0.38 ± 0.04 mm/cm). In contrast, postpubertal boys had longer upper airways (66.5 ± 9.2 vs 52.2 ± 7.0 mm) and normalized airway length/body height (0.38 ± 0.05 vs 0.33 ± 0.05 mm/cm) than girls. CONCLUSIONS Although boys have equal or shorter airway length compared with girls among prepubertal children, after puberty, airway length and airway length normalized for body height are significantly greater in boys than in girls. These data suggest that important anatomic changes at puberty occur in a gender-specific manner, which may be important in explaining the male predisposition to pharyngeal collapse in adults. PMID:17908723

[Treatment of calcaneal fractures using the medial approach for open reduction].

PubMed

Vanĕcek, L; Malkus, T; Dungl, P

2003-01-01

A comprehensive evaluation of the treatment of calcaneal fractures by open reduction is presented. The long-term results are compared with the relevant literature data. In the period from 1987 to 2000, 60 displaced fractures of the calcaneus were treated in 51 patients. Of these, 49 patients suffered the fracture by falling from a height, which is generally the most common cause. Only two patients were injured during sports activities. Thirty eight injuries were classified as fractures of the joint depression type and 22 as fractures of the tongue type. The patients had surgery on the day they sustained the injury or after edema had subsided, if this was present on admission. The interval between injury and surgery was 4.6 days on the average. The fracture was fixed with Kirschner's wires (Kw) in 53 cases, a Kirshcner's wire and a hook-nail in five cases and a Kirchner's wire and a spongious screw in two patients. In May 2001, 23 patients were available for evaluation after a follow-up period of 6 to 120 months. The patients underwent clinical and radiographic examination and filled a questionnaire. The fracture type was defined on the basis of the Essex-Lopresti classification system. Outcomes were scored according to the Creighton-Nebraska Health Foundation rating system that assessed pain, range of motion, edema, a change in shoe size, patient's activity after therapy termination and return to a job. In May 2001, 23 patients, with a follow-up ranging from 6 to 120 months were checked up. Of them, 20 (86.9%) had neither clinical manifestations nor subjective complaints. Three patients retired because of persisting complaints, two with disability pensions and one with an old-age pension. A total of 19 patients were evaluated by the Creighton-Nebraska Health Foundation rating system. The average score was 90.8 points. The results were excellent in 15 patients, good in three and poor in one patient. The complications reported by the patients included superficial infection in two, thromboembolic disease in one, and hypesthesia on the medial side of the leg in two patients. The optimal mode of treatment in dislocated intra-articular fractures of the calcaneus still remains open to discussion. Should conservative or surgical therapy be used? In agreement with others, the authors preferred early surgical intervention. This facilitated a better congruence of the dorsal articular surface. The average remaining dislocation of the articular surface was 1.1 mm in surgically treated as against the average of 4.7 mm in conservatively treated patients. It was possible to restore the length, height and width, and the correct axial position of the calcaneus by this surgery from the medial approach. However, in indicated cases, the procedure required an additional intervention from the lateral approach through a mini-incision. As reported in the literature, other authors have achieved comparable, or even better results but on the basis of either the lateral or the plantar approach. The application of primary spongioplasty or primary arthrodesis of the subtalar joint is discussed. The advantages of preoperative examination by computer-assisted tomography are emphasized. Good outcomes of the treatment of intra-articular, dislocated calcaneal fractures depend on a correct shape and position of the dorsal articular surface of the calcaneus. The open reduction procedure from the medial approach based on the principles of McReynold's technique allowed us to accomplish both these criteria.

Hip fracture in hospitalized medical patients

PubMed Central

2013-01-01

Background The aim of the present study is to analyze the incidence of hip fracture as a complication of admissions to internal medicine units in Spain. Methods We analyzed the clinical data of 2,134,363 adults who had been admitted to internal medicine wards. The main outcome was a diagnosis of hip fracture during hospitalization. Outcome measures included rates of in-hospital fractures, length of stay and cost. Results A total of 1127 (0.057%) admittances were coded with an in-hospital hip fracture. In hospital mortality rate was 27.9% vs 9.4%; p < 0.001, and the mean length of stay was significantly longer for patients with a hip fracture (20.7 days vs 9.8 days; p < 0.001). Cost were higher in hip-fracture patients (6927€ per hospitalization vs 3730€ in non fracture patients). Risk factors related to fracture were: increasing age by 10 years increments (OR 2.32 95% CI 2.11-2.56), female gender (OR 1.22 95% CI 1.08-1.37), admission from nursing home (OR 1.65 95% CI 1.27-2.12), dementia (1.55 OR 95% CI1.30-1.84), malnutrition (OR 2.50 95% CI 1.88-3.32), delirium (OR 1.57 95% CI 1.16-2.14), and anemia (OR 1.30 95%CI 1.12-1.49). Conclusions In-hospital hip fracture notably increased mortality during hospitalization, doubling the mean length of stay and mean cost of admission. These are reasons enough to stress the importance of designing and applying multidisciplinary plans focused on reducing the incidence of hip fractures in hospitalized patients. PMID:23298165

Fractures system within Qusaiba shale outcrop and its relationship to the lithological properties, Qasim area, Central Saudi Arabia

NASA Astrophysics Data System (ADS)

Ibrahim, Mohamed I. M.; Hariri, Mustafa M.; Abdullatif, Osman M.; Makkawi, Mohammad H.; Elzain, Hussam

2017-09-01

The basal Qusaiba hot shale member of Qalibah Formation is considered to be an important source rock in the Paleozoic petroleum system of Saudi Arabia and an exploration target for tight shale as one of the Unconventional resources of petroleum. This work has been carried out to understand the fractures network of Qusaiba shale member in outcrops located to the west of Qusayba' village in Al-Qasim area, Central Saudi Arabia. The main objective of this study is to understand the distribution of natural fractures over different lithological units. Description data sheets were used for the detailed lithological description of Qusaiba shale member on two outcrops. Spot-7 and Landsat ETM+ satellite images were used for lineament mapping and analyses on a regional scale in a GIS environment. Fractures characterization in outcrop-scale was conducted by using linear scanline method. Qusaiba shale member in the study area consists of 5 main lithofacies, divided based on their sedimentary structures and petrographical properties, from base to top in the outcrops, the lithofacies are; fissile shale, very fine-grained micaceous siltstone, bioturbated mudstone, very fine to fine-grained hummocky cross-stratified sandstone, and fine to medium-grained low/high angle cross-stratified sandstone lithofacies. Lineaments interpretation of the Spot-7 and Landsat ETM+ satellite images showed two major directions in the study area; 320° that could be related to Najd fault system and 20° that could be related to the extensional activities which took place after Amar collision. Fractures are much denser in the fissile shale and mudstone lithofacies than sandstones lithofacies, and average spacing is smaller in the fissile shale and mudstone lithofacies than sandstones lithofacies. Lineaments and large-scale fractures are Non-Stratabound fractures and they deal with the area as one big mechanical unit, but small-scale fractures are Stratabound fractures that propose different mechanical units within Qusaiba shale member in the study area. The fractures network in the study area has a wide range of properties related to fractures density, length, spacing, height, and termination degree. The conceptual multi-scale model divides the fractures in the study area into 4 orders depending on the available data that have been observed from satellite images and field. The multi-scale fractures model that was generated in this study could help to understand the distribution of stratigraphically controlled fractures when integrated with flow simulation models. Overall, this work could have a significant contribution to tight shale exploration plans in the subsurface by providing some knowledge about the fractures mechanical behavior of the lower part of Qusaiba shale member of Qalibah Formation.

The relation between height, foot length, pelvic adequacy and mode of delivery.

PubMed

Van Bogaert, L J

1999-02-01

To investigate the value of maternal height and foot length as predictors of pelvic adequacy and to evaluate the influence of body components' proportions on the mode of delivery. Retrospective study of the anthropometry of women having normal vertex deliveries (NVD), caesarean sections (CS) and vaginal birth after caesarean (VBAC). NVD patients were taller, had a longer vertebral column, longer lower limbs and longer feet than CS and than VBAC patients. The anthropometric measurements of VBAC patients yielded values intermediate between CS and NVD patients. The ratios of height to any of the other measured variables (vertebral column, lower limb and foot length) were similar in the three groups indicating that the body proportions were the same. Maternal height and foot length are of limited value as predictors of pelvic (in-)adequacy. The anthropometric features of women delivered by CS only are similar to those of women having a vaginal birth after Caesarean.

Associations between birth size and later height from infancy through adulthood: An individual based pooled analysis of 28 twin cohorts participating in the CODATwins project.

PubMed

Jelenkovic, Aline; Yokoyama, Yoshie; Sund, Reijo; Hur, Yoon-Mi; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas Sevenius; Ooki, Syuichi; Ullemar, Vilhelmina; Almqvist, Catarina; Magnusson, Patrik K E; Saudino, Kimberly J; Stazi, Maria A; Fagnani, Corrado; Brescianini, Sonia; Nelson, Tracy L; Whitfield, Keith E; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Cutler, Tessa L; Hopper, John L; Llewellyn, Clare H; Fisher, Abigail; Corley, Robin P; Huibregtse, Brooke M; Derom, Catherine A; Vlietinck, Robert F; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Alexandra Burt, S; Klump, Kelly L; Dubois, Lise; Boivin, Michel; Brendgen, Mara; Dionne, Ginette; Vitaro, Frank; Willemsen, Gonneke; Bartels, Meike; van Beijsterveld, Catharina E M; Craig, Jeffrey M; Saffery, Richard; Rasmussen, Finn; Tynelius, Per; Heikkilä, Kauko; Pietiläinen, Kirsi H; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Haworth, Claire M A; Plomin, Robert; Ji, Fuling; Ning, Feng; Pang, Zengchang; Rebato, Esther; Tarnoki, Adam D; Tarnoki, David L; Kim, Jina; Lee, Jooyeon; Lee, Sooji; Sung, Joohon; Loos, Ruth J F; Boomsma, Dorret I; Sørensen, Thorkild I A; Kaprio, Jaakko; Silventoinen, Karri

2018-05-01

There is evidence that birth size is positively associated with height in later life, but it remains unclear whether this is explained by genetic factors or the intrauterine environment. To analyze the associations of birth weight, length and ponderal index with height from infancy through adulthood within mono- and dizygotic twin pairs, which provides insights into the role of genetic and environmental individual-specific factors. This study is based on the data from 28 twin cohorts in 17 countries. The pooled data included 41,852 complete twin pairs (55% monozygotic and 45% same-sex dizygotic) with information on birth weight and a total of 112,409 paired height measurements at ages ranging from 1 to 69 years. Birth length was available for 19,881 complete twin pairs, with a total of 72,692 paired height measurements. The association between birth size and later height was analyzed at both the individual and within-pair level by linear regression analyses. Within twin pairs, regression coefficients showed that a 1-kg increase in birth weight and a 1-cm increase in birth length were associated with 1.14-4.25 cm and 0.18-0.90 cm taller height, respectively. The magnitude of the associations was generally greater within dizygotic than within monozygotic twin pairs, and this difference between zygosities was more pronounced for birth length. Both genetic and individual-specific environmental factors play a role in the association between birth size and later height from infancy to adulthood, with a larger role for genetics in the association with birth length than with birth weight. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Bicuspid Axial Wall Height Effect on CAD/CAM Crown Fracture Mode on Preparations Containing Advanced Total Occlusal Convergence.

PubMed

Miller, Matthew; DuVall, Nicholas; Brewster, John; Wajdowicz, Michael N; Harris, Ashley; Roberts, Howard W

2018-02-18

To evaluate bicuspid axial wall height effect on the fracture mode of adhesively luted, all-ceramic CAD/CAM crowns with a 20° total occlusal convergence (TOC). Recently extracted premolars were randomly divided into 4 groups (n = 12) with all-ceramic crown preparations accomplished using a high-speed handpiece inserted into a milling device. Specimens were prepared containing occlusogingival axial wall heights of 3, 2, and 1 mm as well as a group containing a flat preparation surface with no axial wall height. All preparations contained a 20° TOC. Completed preparation surface area was determined, and preparation features confirmed using a digital measuring microscope. Scanned preparations (CEREC) were fitted with milled and crystallized lithium disilicate full coverage restorations and luted with a self-etching adhesive resin cement after hydrofluoric acid etching and silanation. All manufacturer recommendations were followed. Specimens were stored at 37°C/98% humidity for 24 hours. Specimens were tested to failure at a 45° angle to the long axis of the tooth root on a universal testing machine. Failure load was converted to MPa using the available bonding surface area with mean data analyzed using Kruskal-Wallis/Dunn's (p = 0.05) RESULTS: The 3 mm preparation height specimens were similar to the 2 mm specimens, and both demonstrated significantly stronger failure load than the 1 mm axial wall height and flat preparation specimens. The flat preparation and 1 mm axial wall height specimens all failed adhesively, while the 2 mm and 3 mm specimens failed largely due to tooth fracture. Further evidence is provided that CAD/CAM adhesive techniques may compensate for less than ideal preparation features. Under the conditions of this study, bicuspid preparations with a 20° TOC restored with adhesively luted, CAD/CAM e.max CAD crowns require at least 2 mm of axial wall height, but further planned fatigue studies are necessary before definitive recommendations can be made. © 2018 by the American College of Prosthodontists.

The factor-of-risk biomechanical approach predicts hip fracture in men and women: the Framingham Study.

PubMed

Dufour, A B; Roberts, B; Broe, K E; Kiel, D P; Bouxsein, M L; Hannan, M T

2012-02-01

We examined the relation between a biomechanical measure, factor-of-risk, and hip fracture risk in 1,100 men and women from the Framingham Study and found that it predicted hip fracture (men, ORs of 1.8; women, 1.2-1.4). Alternative methods of predicting hip fracture are needed since 50% of adults who fracture do not have osteoporosis by bone mineral density (BMD) measurements. One method, factor-of-risk (Φ), computes the ratio of force on the hip in a fall to femoral strength. We examined the relation between Φ and hip fracture in 1,100 subjects from the Framingham Study with measured hip BMD, along with weight, height, and age, collected in 1988-1989. We estimated both peak and attenuated force applied to the hip in a sideways fall from standing height, where attenuated force incorporated cushioning effects of trochanteric soft tissue. Femoral strength was estimated from femoral neck BMD, using cadaveric femoral strength data. Sex-specific, age-adjusted survival models were used to calculate hazard ratios (HR) and 95% confidence intervals for the relation between Φ (peak), Φ (attenuated), and their components with hip fracture. In 425 men and 675 women (mean age, 76 years), 136 hip fractures occurred over median follow-up of 11.3 years. Factor-of-risk, Φ, was associated with increased age-adjusted risk for hip fracture. One standard deviation increase in Φ (peak) and Φ (attenuated) was associated with HR of 1.88 and 1.78 in men and 1.23 and 1.41 in women, respectively. Examining components of Φ, in women, we found fall force and soft tissue thickness were predictive of hip fracture independent of femoral strength (was estimated from BMD). Thus, both Φ (peak) and Φ (attenuated) predict hip fracture in men and women. These findings suggest additional studies of Φ predicting hip fracture using direct measurements of trochanteric soft tissue.

Comparative evaluation of fracture resistance of Ceramic Veneer with three different incisal design preparations - An In-vitro Study.

PubMed

Jankar, Ajit S; Kale, Yogesh; Kangane, Suresh; Ambekar, Anand; Sinha, Manish; Chaware, Sachin

2014-02-01

Ceramic veneer fracture has occurred mainly at the incisal edge of the veneer because of greater stress. This study compares and evaluates the fracture resistance ceramic veneers with three different incisal preparations. 15 human permanent maxillary central incisor extracted were selected which were divided into three groups of 5 each having a different Incial design Preparation. Group 1: No Incisal reduction with facio- incisal bevel, Group 2 : 1 mm incisal reduction with butt joint, Group 3 : 1 mm incisal reduction with 1 mm height of Palatal chamfer. It was found that Group III had greater fracture resistance as compared to Group I and Group II. Group I had least fracture resistance as compared to Group II and III. Group II had greater fracture resistance as compared to Group I but less than Group III. Ceramic veneer with 1mm incisal reduction with 1mm height of palatal chamfer showed highest fracture resistance as compared to 1mm incisal reduction with butt joint and no incisal reduction with facial-incisal bevel, in order to achieve better esthetic and functional results. The palatal chamfer margin results in preservation of some peripheral enamel layer, which eliminates the micro leakage at the palatal margin-restoration interface and also effectively counteracting shear stress. This design provides a definite seat for cementation. How to cite the article: Jankar AS, Kale Y, Kangane S, Ambekar A, Sinha M, Chaware S. Comparative evaluation of fracture resistance of Ceramic Veneer with three different incisal design preparations - An In-vitro Study. J Int Oral Health 2014;6(1):48-54.

Calcaneotalar ratio: a new concept in the estimation of the length of the calcaneus.

PubMed

David, Vikram; Stephens, Terry J; Kindl, Radek; Ang, Andy; Tay, Wei-Han; Asaid, Rafik; McCullough, Keith

2015-01-01

Maintaining the calcaneal length after calcaneal fractures is vital to restoring the normal biomechanics of the foot, because it acts as an important lever arm to the plantarflexors of the foot. However, estimation of the length of the calcaneus to be reconstructed in comminuted calcaneal fractures can be difficult. We propose a new method to reliably estimate the calcaneal length radiographically by defining the calcaneotalar length ratio. A total of 100 ankle radiographs with no fracture in the calcaneus or talus taken in skeletally mature patients were reviewed by 6 observers. The anteroposterior lengths of the calcaneus and talus were measured, and the calcaneotalar length ratio was determined. The ratio was then used to estimate the length of the calcaneus. Interobserver reliability was determined using Cronbach's α coefficient and Pearson's correlation coefficient. The mean length of the calcaneus was 75 ± 0.6 mm, and the mean length of the talus was 59 ± 0.5 mm. The calcaneotalar ratio was 1.3. Using this ratio and multiplying it by the talar length, the mean average estimated length of the calcaneus was within 0.7 mm of the known calcaneal length. Cronbach's α coefficient and Pearson's correlation coefficient showed excellent interobserver reliability. The proposed calcaneotalar ratio is a new and reliable method to radiographically estimate the normal length of the calcaneus when reconstructing the calcaneus. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

[Locked volar plating for complex distal radius fractures: maintaining radial length].

PubMed

Jeudy, J; Pernin, J; Cronier, P; Talha, A; Massin, P

2007-09-01

Maintaining radial length, likely to be the main challenge in the treatment of complex distal radius fractures, is necessary for complete grip-strength and pro-supination range recovery. In spite of frequent secondary displacements, bridging external-fixation has remained the reference method, either isolated or in association with additional percutaneous pins or volar plating. Also, there seems to be a relation between algodystrophy and the duration of traction applied on the radio-carpal joint. Fixed-angle volar plating offers the advantage of maintaining the reduction until fracture healing, without bridging the joint. In a prospective study, forty-three consecutive fractures of the distal radius with a positivated ulnar variance were treated with open reduction and fixed-angle volar plating. Results were assessed with special attention to the radial length and angulation obtained and maintained throughout treatment, based on repeated measurements of the ulnar variance and radial angulation in the first six months postoperatively. The correction of the ulnar variance was maintained until complete recovery, independently of initial metaphyseal comminution, and of the amount of radial length gained at reduction. Only 3 patients lost more than 1 mm of radial length after reduction. The posterior tilt of the distal radial epiphysis was incompletely reduced in 13 cases, whereas reduction was partially lost in 6 elderly osteoporotic female patients. There was 8 articular malunions, all of them less than 2 mm. Secondary displacements were found to be related to a deficient locking technique. Eight patients developed an algodystropy. The risk factors for algodystrophy were articular malunion, associated posterior pining, and associated lesions of the ipsilateral upper limb. Provided that the locking technique was correct, this type of fixation appeared efficient in maintaining the radial length in complex fractures of the distal radius. The main challenge remains the reduction of displaced articular fractures. Based on these results, it is not possible to conclude that this method is superior to external fixation.

Thermal drawdown-induced flow channeling in a single fracture in EGS

DOE PAGES

Guo, Bin; Fu, Pengcheng; Hao, Yue; ...

2016-01-28

Here, the evolution of flow pattern along a single fracture and its effects on heat production is a fundamental problem in the assessments of engineered geothermal systems (EGS). The channelized flow pattern associated with ubiquitous heterogeneity in fracture aperture distribution causes non-uniform temperature decrease in the rock body, which makes the flow increasingly concentrated into some preferential paths through the action of thermal stress. This mechanism may cause rapid heat production deterioration of EGS reservoirs. In this study, we investigated the effects of aperture heterogeneity on flow pattern evolution in a single fracture in a low-permeability crystalline formation. We developedmore » a numerical model on the platform of GEOS to simulate the coupled thermo-hydro-mechanical processes in a penny-shaped fracture accessed via an injection well and a production well. We find that aperture heterogeneity generally exacerbates flow channeling and reservoir performance generally decreases with longer correlation length of aperture field. The expected production life is highly variable (5 years to beyond 30 years) when the aperture correlation length is longer than 1/5 of the well distance, whereas a heterogeneous fracture behaves similar to a homogeneous one when the correlation length is much shorter than the well distance. Besides, the mean production life decreases with greater aperture standard deviation only when the correlation length is relatively long. Although flow channeling is inevitable, initial aperture fields and well locations that enable tortuous preferential paths tend to deliver long heat production lives.« less

Investigating Some Technical Issues on Cohesive Zone Modeling of Fracture

NASA Technical Reports Server (NTRS)

Wang, John T.

2011-01-01

This study investigates some technical issues related to the use of cohesive zone models (CZMs) in modeling fracture processes. These issues include: why cohesive laws of different shapes can produce similar fracture predictions; under what conditions CZM predictions have a high degree of agreement with linear elastic fracture mechanics (LEFM) analysis results; when the shape of cohesive laws becomes important in the fracture predictions; and why the opening profile along the cohesive zone length needs to be accurately predicted. Two cohesive models were used in this study to address these technical issues. They are the linear softening cohesive model and the Dugdale perfectly plastic cohesive model. Each cohesive model constitutes five cohesive laws of different maximum tractions. All cohesive laws have the same cohesive work rate (CWR) which is defined by the area under the traction-separation curve. The effects of the maximum traction on the cohesive zone length and the critical remote applied stress are investigated for both models. For a CZM to predict a fracture load similar to that obtained by an LEFM analysis, the cohesive zone length needs to be much smaller than the crack length, which reflects the small scale yielding condition requirement for LEFM analysis to be valid. For large-scale cohesive zone cases, the predicted critical remote applied stresses depend on the shape of cohesive models used and can significantly deviate from LEFM results. Furthermore, this study also reveals the importance of accurately predicting the cohesive zone profile in determining the critical remote applied load.

Bone density loss after allogeneic hematopoietic stem cell transplantation: a prospective study.

PubMed

Stern, J M; Sullivan, K M; Ott, S M; Seidel, K; Fink, J C; Longton, G; Sherrard, D J

2001-01-01

The incidence and course of bone density abnormalities following hematopoietic stem cell transplantation are poorly understood and complicated by the impact of multiple factors. Hip, spine, and wrist bone mineral densities (BMDs) were measured in 104 adults (54 women, 54 men; mean age, 40 years [range, 18-64 years]) at 3 and 12 months after allogeneic transplantation. Clinical and laboratory variables were evaluated using univariate and multivariate analyses to determine risk factors for osteoporosis, fracture, and avascular necrosis. At 3 months posttransplantation, combined (male and female) hip, spine, and wrist z scores were -0.35, -0.42, and +0.04 standard deviations, respectively. At 12 months both men and women experienced significant loss of hip BMD (4.2%, P < .0001); changes in the spine and wrist were minimal. The cumulative dose and number of days of glucocorticoid therapy and the number of days of cyclosporine or tacrolimus therapy showed significant associations with loss of BMD; age, total body irradiation, diagnosis, and donor type did not. Nontraumatic fractures occurred in 10.6% of patients and avascular necrosis in 9.6% within 3 years posttransplantation. The decrease in height between pretransplantation and 12 months posttransplantation was significant (P = .0001). Results indicate that loss of BMD after allogeneic stem cell transplantation is common and accelerated by the length of immunosuppressive therapy and cumulative dose of glucocorticoid. An increased incidence of fracture and avascular necrosis may adversely impact long-term quality of life. Prevention of bone demineralization appears warranted after stem cell transplantation.

Is short stature associated with short cervical length?

PubMed

Gagel, Caroline K; Rafael, Timothy J; Berghella, Vincenzo

2010-10-01

We sought to estimate if there is a correlation between maternal height and cervical length in women at high risk for preterm birth. We studied a retrospective cohort of women with singleton gestation and risk factors for preterm birth. Maternal height was categorized as short (<157.5 cm) or not short stature (≥157.5 cm). Cervical length at 14 to 24 weeks was evaluated. Primary outcomes were incidence of initial cervical length <30 mm and incidence of shortest cervical length <25 mm. Four hundred sixteen women met the inclusion criteria. Twenty-two (22.6%) of the short women and 79 (24.5%) of the nonshort women had an initial cervical length <30 mm ( P = 0.81). Twenty-two (23.7%) of the short women and 104 (32.2%) of the nonshort women had a cervical length <25 mm for shortest cervical length measurement ( P = 0.15). In women with singleton gestation and risk factors for preterm birth, no statistically significant relationship exists between maternal height and initial or shortest cervical length. © Thieme Medical Publishers.

Anthropometry as a predictor of vertical jump heights derived from an instrumented platform.

PubMed

Caruso, John F; Daily, Jeremy S; Mason, Melissa L; Shepherd, Catherine M; McLagan, Jessica R; Marshall, Mallory R; Walker, Ron H; West, Jason O

2012-01-01

The current study purpose examined the vertical height-anthropometry relationship with jump data obtained from an instrumented platform. Our methods required college-aged (n = 177) subjects to make 3 visits to our laboratory to measure the following anthropometric variables: height, body mass, upper arm length (UAL), lower arm length, upper leg length, and lower leg length. Per jump, maximum height was measured in 3 ways: from the subjects' takeoff, hang times, and as they landed on the platform. Standard multivariate regression assessed how well anthropometry predicted the criterion variance per gender (men, women, pooled) and jump height method (takeoff, hang time, landing) combination. Z-scores indicated that small amounts of the total data were outliers. The results showed that the majority of outliers were from jump heights calculated as women landed on the platform. With the genders pooled, anthropometry predicted a significant (p < 0.05) amount of variance from jump heights calculated from both takeoff and hang time. The anthropometry-vertical jump relationship was not significant from heights calculated as subjects landed on the platform, likely due to the female outliers. Yet anthropometric data of men did predict a significant amount of variance from heights calculated when they landed on the platform; univariate correlations of men's data revealed that UAL was the best predictor. It was concluded that the large sample of men's data led to greater data heterogeneity and a higher univariate correlation. Because of our sample size and data heterogeneity, practical applications suggest that coaches may find our results best predict performance for a variety of college-aged athletes and vertical jump enthusiasts.

Fracture surfaces of granular pastes.

PubMed

Mohamed Abdelhaye, Y O; Chaouche, M; Van Damme, H

2013-11-01

Granular pastes are dense dispersions of non-colloidal grains in a simple or a complex fluid. Typical examples are the coating, gluing or sealing mortars used in building applications. We study the cohesive rupture of thick mortar layers in a simple pulling test where the paste is initially confined between two flat surfaces. After hardening, the morphology of the fracture surfaces was investigated, using either the box counting method to analyze fracture profiles perpendicular to the mean fracture plane, or the slit-island method to analyze the islands obtained by cutting the fracture surfaces at different heights, parallel to the mean fracture plane. The fracture surfaces were shown to exhibit scaling properties over several decades. However, contrary to what has been observed in the brittle or ductile fracture of solid materials, the islands were shown to be mass fractals. This was related to the extensive plastic flow involved in the fracture process.

Rock fracture processes in chemically reactive environments

NASA Astrophysics Data System (ADS)

Eichhubl, P.

2015-12-01

Rock fracture is traditionally viewed as a brittle process involving damage nucleation and growth in a zone ahead of a larger fracture, resulting in fracture propagation once a threshold loading stress is exceeded. It is now increasingly recognized that coupled chemical-mechanical processes influence fracture growth in wide range of subsurface conditions that include igneous, metamorphic, and geothermal systems, and diagenetically reactive sedimentary systems with possible applications to hydrocarbon extraction and CO2 sequestration. Fracture processes aided or driven by chemical change can affect the onset of fracture, fracture shape and branching characteristics, and fracture network geometry, thus influencing mechanical strength and flow properties of rock systems. We are investigating two fundamental modes of chemical-mechanical interactions associated with fracture growth: 1. Fracture propagation may be aided by chemical dissolution or hydration reactions at the fracture tip allowing fracture propagation under subcritical stress loading conditions. We are evaluating effects of environmental conditions on critical (fracture toughness KIc) and subcritical (subcritical index) fracture properties using double torsion fracture mechanics tests on shale and sandstone. Depending on rock composition, the presence of reactive aqueous fluids can increase or decrease KIc and/or subcritical index. 2. Fracture may be concurrent with distributed dissolution-precipitation reactions in the hostrock beyond the immediate vicinity of the fracture tip. Reconstructing the fracture opening history recorded in crack-seal fracture cement of deeply buried sandstone we find that fracture length growth and fracture opening can be decoupled, with a phase of initial length growth followed by a phase of dominant fracture opening. This suggests that mechanical crack-tip failure processes, possibly aided by chemical crack-tip weakening, and distributed solution-precipitation creep in the hostrock can independently affect fracture opening displacement and thus fracture aperture profiles and aperture distribution.

[Effectiveness of long segment fixation combined with vertebroplasty for severe osteoporotic thoracolumbar compressive fractures].

PubMed

Xu, Zixing; Xu, Weihong; Wang, Changsheng; Luo, Hongbin; Li, Guishuang; Chen, Rongsheng

2013-11-01

To study the effectiveness of long segment fixation combined with vertebroplasty (LSF-VP) for severe osteoporotic thoracolumbar compressive fractures with kyphosis deformity. Between March 2006 and May 2012, a retrospective analysis was made on the clinical data of 48 cases of severe osteoporotic thoracolumbar compressive fractures with more than 50% collapse of the anterior vertebral body or more than 400 of sagittal angulation, which were treated by LSF-VP in 27 cases (LSF-VP group) or percutaneous kyphoplasty (PKP) in 21 cases (PKP group). All patients suffered from single thoracolumbar vertebral compressive fracture at T11 to L2. There was no significant difference in gender, age, spinal segment, and T values of bone mineral density between 2 groups (P > 0.05). The effectiveness of the treatment was appraised by visual analogue scale (VAS), Cobb angle of thoracolumbar kyphosis, height of anterior/posterior vertebral body, and compressive ratio of vertebrae before and after operations. The LSF-VP group had longer operation time, hospitalization days, and more bone cement injection volume than the PKP group, showing significant differences (P < 0.05). Intraoperative blood loss in LSF-VP group ranged from 220 to 1,050 mL (mean, 517 mL). No pulmonaryor cerebral embolism or cerebrospinal fluid leakage was found in both groups. Asymptomatic bone cement leakage was found in 3 cases of LSF-VP group and 2 cases of PKP group. The patients were followed up for 16-78 months (mean, 41.1 months) in LSF-VP group, and 12-71 months (mean, 42.1 months) in PKP group. No fixation failure such as loosened or broken pedicle screw was found in LSF-VP group during the follow-up, and no re-fracture or adjacent vertebral body fracture was found. Two cases in PKP group at 39 and 56 months after operation respectively were found to have poor maintenance of vertebral height and loss of rectification (Cobb angle was more than 40 degrees) with recurrence of pain, which were treated by second surgery of LSF-VP; another case had compressive fracture of the adjacent segment and thoracolumbar kyphosis at 16 months after operation, which was treated by second surgery of LSF-VP. There were significant differences in the other indexes between each pair of the three time points (P < 0.05), except the Cobb angle of thoracolumbar kyphosis, and the height of posterior vertebral body between discharge and last follow-up in LSF-VP group, and except the Cobb angle of thoracolumbar kyphosis and compressive ratio of bertebrae between discharge and last follow-up in PKP group (P > 0.05). After operation, the other indexes of LSF-VP group were significantly better than those of PKP group at each time point (P < 0.05), except the VAS score and the height of posterior vertebral body at discharge (P > 0.05). The effectiveness of LSF-VP is satisfactory in treating severe osteoporotic thoracolumbar compressive fractures with kyphosis deformity. LSF-VP can acquire better rectification of kyphosis and recovery of vertebral body height than PKP.

An integrated profile of natural fractures in gas-bearing shale complex (Pomerania, Poland): based on structural profiling of oriented core and borehole logging data.

NASA Astrophysics Data System (ADS)

Bobek, Kinga; Jarosiński, Marek; Stadtmuller, Marek; Pachytel, Radomir; Lis-Śledziona, Anita

2016-04-01

Natural fractures in gas-bearing shales has significant impact on reservoir stimulation and increase of exploitation. Density of natural fractures and their orientation in respect to the maximum horizontal stress are crucial for propagation of technological hydraulic fractures. Having access to continuous borehole core profile and modern geophysical logging from several wells in the Pomeranian part of the Early Paleozoic Baltic Basin (Poland) we were able to compare the consistency of structural interpretation of several data sets. Although, final aim of our research is to optimize the method of fracture network reconstruction on a reservoir scale, at a recent stage we were focused on quantitative characterization of tectonic structures in a direct vicinity of boreholes. The data we have, cover several hundred meters long profiles of boreholes from the Ordovician and Silurian shale complexes. Combining different sets of data we broaden the scale of observation from borehole core (5 cm radius), through XRMI scan of a borehole wall (10 cm radius), up to penetration of a signal of an acoustic dipole logging (several tens of cm range). At the borehole core we examined the natural tectonic structures and mechanically significant features, like: mineral veins, fractured veins, bare fractures, slickensides, fault zones, stylolites, bedding plane and mechanically contrasting layers. We have also noticed drilling-induced features like centerline fractures and core disking, controlled by a recent tectonic stress. We have measured the orientation of fractures, their size, aperture and spacing and also describe the character of veins and tried to determine the stress regime responsible for fault slippage and fracture propagation. Wide range of analyzed features allowed us to discriminate fracture sets and reconstruct tectonic evolution of the complex. The most typical for analyzed shale complexes are steep and vertical strata-bound fractures that create an orthogonal joint system, which is locally disturbed by small-scale faults and fractures, associated with them. For regular joints, observed on borehole core, we have calculated variation of mean height and area and volume of mineralization for veins. Fracture density variation reveals good correlation with lithological shale formations which are comparable with Consistent Mechanical Units differentiated based on detailed lithological profiling and geophysical data (see Pachytel et al., this issue).We have also proposed a new method of a rose diagram construction presenting strike of fractures taking into account their size and angular error bar in strike determination. Each fracture was weighted with its length or aperture and an angular error was included by blurring the less credible records. This allowed for more precise adjustment of fracture sets direction in comparison to conventional diagrams without weighting procedure. Recently, we are processing acoustic dipole logs for anisotropy analyses aiming in comparison with density of fracture sets. Our study, which is conducted in the frame of ShaleMech Project (within Blue Gas Program) is in progress, thus the presented results should be considered as preliminary.

Influence of the geometry of curved artificial canals on the fracture of rotary nickel-titanium instruments subjected to cyclic fatigue tests.

PubMed

Lopes, Hélio P; Vieira, Márcia V B; Elias, Carlos N; Gonçalves, Lucio S; Siqueira, José F; Moreira, Edson J L; Vieira, Victor T L; Souza, Letícia C

2013-05-01

This study evaluated the influence of different features of canal curvature geometry on the number of cycles to fracture of a rotary nickel-titanium endodontic instrument subjected to a cyclic fatigue test. BioRaCe BR4C instruments (FKG Dentaire, La Chaux-de Fonds, Switzerland) were tested in 4 grooves simulating curved metallic artificial canals, each one measuring 1.5 mm in width, 20 mm in total length, and 3.5 mm in depth with a U-shaped bottom. The parameters of curvature including the radius and arc lengths and the position of the arc differed in the 4 canal designs. Fractured surfaces and helical shafts of the separated instruments were analyzed by scanning electron microscopy. The Student's t test showed that a significantly lower number of cycles to fracture values were observed for instruments tested in canals with the smallest radius, the longest arc, and the arc located in the middle portion of the canal. Scanning electron microscopic analysis of the fracture surfaces revealed morphologic characteristics of ductile fracture. Plastic deformation was not observed in the helical shaft of the fractured instruments. Curvature geometry including the radius and arc lengths and the position of the arc along the root canal influence the number of cycles to fracture of rotary nickel-titanium instruments subjected to flexural load. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Biologic fixation through bridge plating for comminuted shaft fracture of the clavicle: technical aspects and prospective clinical experience with a minimum of 12-month follow-up.

PubMed

Jung, Gu Hee; Park, Chang-Min; Kim, Jae-Do

2013-12-01

For comminuted shaft fracture of clavicle, the operative goal, aside from sound bone healing without complications of direct reduction, is maintenance of the original length in order to maintain the normal biomechanics of adjacent joint. Our bridge plating technique utilizing distraction through a lumbar spreader was expected to be effective for restoring clavicular length with soft tissue preservation. However, there are two disadvantages. First, there is more exposure to radiation compared to conventional plating; and second, it is difficult to control the rotational alignment. Despite these disadvantages, our technique has important benefits, in particular, the ability to preserve clavicular length without soft tissue injury around the fracture site.

Comparison of submuscular and open plating of pediatric femur fractures: a retrospective review.

PubMed

Abbott, Matthew D; Loder, Randall T; Anglen, Jeffrey O

2013-01-01

Plate osteosynthesis is an accepted method of treatment of pediatric femur fractures. Historically, open plating has been used. Submuscular bridge plating has gained recent popularity due to the theoretical advantages of decreased operative time, decreased blood loss, and decreased risk for infection. The purpose of this study was to compare submuscular bridge plating to open plating of pediatric femur fractures. We retrospectively reviewed 79 patients (80 treated femur fractures) between 1999 and 2011 that underwent either open plating (58 femur fractures) or submuscular bridge plating (22 femur fractures). The outcome measures evaluated were operative time, estimated blood loss, malunion, leg length discrepancy, time to union, infection, unplanned return to the operating room, and length of hospital stay after surgery. Among our outcome measures, there was no difference between the 2 groups in terms of operative time, leg length discrepancy, time to union, infection, or length of hospital stay after surgery. There was greater estimated blood loss in the open plating group (P≤0.0001) and greater rotational asymmetry in the submuscular bridge plating group (P=0.005). There was a trend of increased unplanned return to the operating room in the open plating group (5/58 vs. 0/22) although not statistically significant (P=0.32). Submuscular bridge plating and open plating seem to be equally viable options for the management of pediatric diaphyseal femur fractures. In this study, open plating had an increase in estimated blood loss and a trend of more unplanned returns to the operating room, whereas submuscular bridge plating had an increase in asymptomatic rotational asymmetry. Further larger, prospective, randomized studies are necessary to further evaluate these operative techniques. Therapeutic Level III.

Genome-wide Analysis of Body Proportion Classifies Height-Associated Variants by Mechanism of Action and Implicates Genes Important for Skeletal Development.

PubMed

Chan, Yingleong; Salem, Rany M; Hsu, Yu-Han H; McMahon, George; Pers, Tune H; Vedantam, Sailaja; Esko, Tonu; Guo, Michael H; Lim, Elaine T; Franke, Lude; Smith, George Davey; Strachan, David P; Hirschhorn, Joel N

2015-05-07

Human height is a composite measurement, reflecting the sum of leg, spine, and head lengths. Many common variants influence total height, but the effects of these or other variants on the components of height (body proportion) remain largely unknown. We studied sitting height ratio (SHR), the ratio of sitting height to total height, to identify such effects in 3,545 African Americans and 21,590 individuals of European ancestry. We found that SHR is heritable: 26% and 39% of the total variance of SHR can be explained by common variants in European and African Americans, respectively, and global European admixture is negatively correlated with SHR in African Americans (r(2) ≈ 0.03). Six regions reached genome-wide significance (p < 5 × 10(-8)) for association with SHR and overlapped biological candidate genes, including TBX2 and IGFBP3. We found that 130 of 670 height-associated variants are nominally associated (p < 0.05) with SHR, more than expected by chance (p = 5 × 10(-40)). At these 130 loci, the height-increasing alleles are associated with either a decrease (71 loci) or increase (59 loci) in SHR, suggesting that different height loci disproportionally affect either leg length or spine/head length. Pathway analyses via DEPICT revealed that height loci affecting SHR, and especially those affecting leg length, show enrichment of different biological pathways (e.g., bone/cartilage/growth plate pathways) than do loci with no effect on SHR (e.g., embryonic development). These results highlight the value of using a pair of related but orthogonal phenotypes, in this case SHR with height, as a prism to dissect the biology underlying genetic associations in polygenic traits and diseases. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Image processing for quantifying fracture orientation and length scale transitions during brittle deformation

NASA Astrophysics Data System (ADS)

Rizzo, R. E.; Healy, D.; Farrell, N. J.

2017-12-01

We have implemented a novel image processing tool, namely two-dimensional (2D) Morlet wavelet analysis, capable of detecting changes occurring in fracture patterns at different scales of observation, and able of recognising the dominant fracture orientations and the spatial configurations for progressively larger (or smaller) scale of analysis. Because of its inherited anisotropy, the Morlet wavelet is proved to be an excellent choice for detecting directional linear features, i.e. regions where the amplitude of the signal is regular along one direction and has sharp variation along the perpendicular direction. Performances of the Morlet wavelet are tested against the 'classic' Mexican hat wavelet, deploying a complex synthetic fracture network. When applied to a natural fracture network, formed triaxially (σ1>σ2=σ3) deforming a core sample of the Hopeman sandstone, the combination of 2D Morlet wavelet and wavelet coefficient maps allows for the detection of characteristic scale orientation and length transitions, associated with the shifts from distributed damage to the growth of localised macroscopic shear fracture. A complementary outcome arises from the wavelet coefficient maps produced by increasing the wavelet scale parameter. These maps can be used to chart the variations in the spatial distribution of the analysed entities, meaning that it is possible to retrieve information on the density of fracture patterns at specific length scales during deformation.

Implant-supported rehabilitation after treatment of atrophic mandibular fractures: report of two cases.

PubMed

Oliveira, Leandro Benetti de; Gabrielli, Marisa Aparecida Cabrini; Gabrielli, Mario Francisco Real; Pereira-Filho, Valfrido Antonio Pereira

2015-12-01

The objective of this article is to present options of rehabilitation with dental implants in two cases of severely atrophic mandibles (<10 mm) after rigid internal fixation of fractures. Two patients who sustained fractures in severely atrophic mandibles with less than 10 mm of bone height were treated by open reduction and internal fixation through a transcervical access. Internal fixation was obtained with 2.4-mm locking reconstruction plates. The first patient presented satisfactory bone height at the area between the mental foramens and after 2 years, received flapless guided implants in the anterior mandible and an immediate protocol prosthesis. The second patient received a tent pole iliac crest autogenous graft after 2 years of fracture treatment and immediate implants. After 5 months, a protocol prosthesis was installed in the second patient. In both cases, the internal fixation followed AO principles for load-bearing osteosynthesis. Both prosthetic devices were Branemark protocol prosthesis. The mandibular reconstruction plates were not removed. Both patients are rehabilitated without complications and satisfied with esthetic and functional results. With the current techniques of internal fixation, grafting, and guided implants, the treatment of atrophic mandible fractures can achieve very good results, which were previously not possible.

Maxillofacial Injuries in Children: A 10 year Retrospective Study.

PubMed

Kambalimath, H V; Agarwal, S M; Kambalimath, Deepashri H; Singh, Mamta; Jain, Neha; Michael, P

2013-06-01

Fractures of facial bones in children are relatively uncommon although both children and adults are subjected to similar types of injuries. This study aims to evaluate the epidemiology of facial bone fractures among children under 14 years, their management and outcome. This retrospective study included maxillofacial injuries treated in 112 children under 14 years admitted due to maxillofacial injuries during the period from 2001 to 2011. Of them ten (8.93 %) were below 5 years, 44 (39.29 %) between 6 and 10 years and 58 (51.78 %) between 11 and 14 years of age. Male to female ratio was 1.8:1. Fall from a height was the most common etiology. The most common jaw involved in the fracture was the mandible. Conservative management was done in 83.04 % of cases and open reduction and internal fixation was performed in 16.96 % of cases. Five (4.46 %) cases accounted for post-operative wound infection. Fracture of the mandible is the most common maxillofacial injury in children, most often caused by fall from a height. The osteogenic potential of the mandible in children leads to conservative management of these fractures. Opportunities for prevention of maxillofacial trauma should be taken into consideration by parents and care takers.

Digital diagnosis and treatment of mandibular condylar fractures based on Extensible Neuro imaging Archive Toolkit (XNAT)

PubMed Central

Ren, Jiayin; He, Mingyun; Huang, Yongqing; Tian, WeiDong; Tang, Wei

2018-01-01

Objectives The treatment of condylar fractures has long been controversial. In this paper, we established a database for accurate measurement, storage, management and analysis of patients’ data, in order to help determine the best treatment plan. Methods First of all, the diagnosis and treatment database was established based on XNAT, including 339 cases of condylar fractures and their related information. Then image segmentation, registration and three-dimensional (3D) measurement were used to measure and analyze the condyle shapes. Statistical analysis was used to analyze the anatomical structure changes of condyle and the surrounding tissues at different stages before and after treatment. The processes of condylar fracture reestablishment at different stages were also dynamically monitored. Finally, based on all these information, the digital diagnosis and treatment plans for condylar fractures were developed. Results For the patients less than 18 years old with no significant dislocation, surgical treatment and conservative treatment were equally effective for intracapsular fracture, and had no significant difference for neck and basal fractures. For patients above 18 years old, there was no significant difference between the two treatment methods for intracapsular fractures; but for condylar neck and basal fractures, surgical treatment was better than conservative treatment. When condylar fracture shift angle was greater than 11 degrees, and mandibular ramus height reduction was greater than 4mm, the patients felt the strongest pain, and their mouths opening was severely restricted. There were 170 surgical cases with condylar fracture shift angel greater than 11 degrees, and 118 of them (69.4%) had good prognosis, 52 of them (30.6%) had complications such as limited mouth opening. There were 173 surgical cases with mandibular ramus height reduction more than 4mm, and 112 of them (64.7%) had good prognosis, 61 of them (35.3%) had complications such as limited mouth opening. Conclusions The establishment of XNAT condylar fracture database is helpful for establishing a digital diagnosis and treatment workflow for mandibular condylar fractures, providing new theoretical foundation and application basis for diagnosis and treatment of condylar fractures. PMID:29432477

Evaluating the effect of internal aperture variability on transport in kilometer scale discrete fracture networks

DOE PAGES

Makedonska, Nataliia; Hyman, Jeffrey D.; Karra, Satish; ...

2016-08-01

The apertures of natural fractures in fractured rock are highly heterogeneous. However, in-fracture aperture variability is often neglected in flow and transport modeling and individual fractures are assumed to have uniform aperture distribution. The relative importance of in-fracture variability in flow and transport modeling within kilometer-scale fracture networks has been under debate for a long time, since the flow in each single fracture is controlled not only by in-fracture variability but also by boundary conditions. Computational limitations have previously prohibited researchers from investigating the relative importance of in-fracture variability in flow and transport modeling within large-scale fracture networks. We addressmore » this question by incorporating internal heterogeneity of individual fractures into flow simulations within kilometer scale three-dimensional fracture networks, where fracture intensity, P 32 (ratio between total fracture area and domain volume) is between 0.027 and 0.031 [1/m]. The recently developed discrete fracture network (DFN) simulation capability, dfnWorks, is used to generate kilometer scale DFNs that include in-fracture aperture variability represented by a stationary log-normal stochastic field with various correlation lengths and variances. The Lagrangian transport parameters, non-reacting travel time, , and cumulative retention, , are calculated along particles streamlines. As a result, it is observed that due to local flow channeling early particle travel times are more sensitive to in-fracture aperture variability than the tails of travel time distributions, where no significant effect of the in-fracture aperture variations and spatial correlation length is observed.« less

Evaluating the effect of internal aperture variability on transport in kilometer scale discrete fracture networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makedonska, Nataliia; Hyman, Jeffrey D.; Karra, Satish

The apertures of natural fractures in fractured rock are highly heterogeneous. However, in-fracture aperture variability is often neglected in flow and transport modeling and individual fractures are assumed to have uniform aperture distribution. The relative importance of in-fracture variability in flow and transport modeling within kilometer-scale fracture networks has been under debate for a long time, since the flow in each single fracture is controlled not only by in-fracture variability but also by boundary conditions. Computational limitations have previously prohibited researchers from investigating the relative importance of in-fracture variability in flow and transport modeling within large-scale fracture networks. We addressmore » this question by incorporating internal heterogeneity of individual fractures into flow simulations within kilometer scale three-dimensional fracture networks, where fracture intensity, P 32 (ratio between total fracture area and domain volume) is between 0.027 and 0.031 [1/m]. The recently developed discrete fracture network (DFN) simulation capability, dfnWorks, is used to generate kilometer scale DFNs that include in-fracture aperture variability represented by a stationary log-normal stochastic field with various correlation lengths and variances. The Lagrangian transport parameters, non-reacting travel time, , and cumulative retention, , are calculated along particles streamlines. As a result, it is observed that due to local flow channeling early particle travel times are more sensitive to in-fracture aperture variability than the tails of travel time distributions, where no significant effect of the in-fracture aperture variations and spatial correlation length is observed.« less

The fragile elderly hip: Mechanisms associated with age-related loss of strength and toughness☆

PubMed Central

Reeve, Jonathan; Loveridge, Nigel

2014-01-01

Every hip fracture begins with a microscopic crack, which enlarges explosively over microseconds. Most hip fractures in the elderly occur on falling from standing height, usually sideways or backwards. The typically moderate level of trauma very rarely causes fracture in younger people. Here, this paradox is traced to the decline of multiple protective mechanisms at many length scales from nanometres to that of the whole femur. With normal ageing, the femoral neck asymmetrically and progressively loses bone tissue precisely where the cortex is already thinnest and is also compressed in a sideways fall. At the microscopic scale of the basic remodelling unit (BMU) that renews bone tissue, increased numbers of actively remodelling BMUs associated with the reduced mechanical loading in a typically inactive old age augments the numbers of mechanical flaws in the structure potentially capable of initiating cracking. Menopause and over-deep osteoclastic resorption are associated with incomplete BMU refilling leading to excessive porosity, cortical thinning and disconnection of trabeculae. In the femoral cortex, replacement of damaged bone or bone containing dead osteocytes is inefficient, impeding the homeostatic mechanisms that match strength to habitual mechanical usage. In consequence the participation of healthy osteocytes in crack-impeding mechanisms is impaired. Observational studies demonstrate that protective crack deflection in the elderly is reduced. At the most microscopic levels attention now centres on the role of tissue ageing, which may alter the relationship between mineral and matrix that optimises the inhibition of crack progression and on the role of osteocyte ageing and death that impedes tissue maintenance and repair. This review examines recent developments in the understanding of why the elderly hip becomes fragile. This growing understanding is suggesting novel testable approaches for reducing risk of hip fracture that might translate into control of the growing worldwide impact of hip fractures on our ageing populations. PMID:24412288

Temporary Percutaneous Pedicle Screw Stabilization Without Fusion of Adolescent Thoracolumbar Spine Fractures.

PubMed

Cui, Shari; Busel, Gennadiy A; Puryear, Aki S

2016-01-01

Pediatric spine trauma often results from high-energy mechanisms. Despite differences in healing potential, comorbidities, and length of remaining life, treatment is frequently based on adult criteria; ligamentous injuries are fused and bony injuries are treated accordingly. In this study, we present short-term results of a select group of adolescent patients treated using percutaneous pedicle screw instrumentation without fusion. An IRB-approved retrospective review was performed at a level 1 pediatric trauma center for thoracolumbar spine fractures treated by percutaneous pedicle screw instrumentation. Patients were excluded if arthrodesis was performed or if instrumentation was not removed. Demographics, injury mechanism, associated injuries, fracture classification, surgical data, radiographic measures, and complications were collected. Radiographs were analyzed for sagittal and coronal wedge angles and vertebral body height ratio and statistical comparisons performed on preoperative and postoperative values. Between 2005 and 2013, 46 patients were treated surgically. Fourteen patients (5 male, 9 female) met inclusion criteria. Injury mechanisms included 8 motor vehicle collisions, 4 falls, and 2 all-terrain vehicle/motorcycle collisions. There were 8 Magerl type A injuries, 4 type B injuries, and 2 type C injuries. There was 1 incomplete spinal cord injury. Implants were removed between 5 and 12 months in 12 patients and after 12 months in 2 patients. Statistical analysis revealed significant postoperative improvement in all radiographic measures (P<0.05). There were no neurological complications, 1 superficial wound dehiscence, and 2 instrumentation failures (treated with standard removal). At last follow-up, 11 patients returned to unrestricted activities including sports. Average follow-up was 9 months after implant removal and 19.3 months after index procedure. Adolescent thoracolumbar fractures present unique challenges and treatment opportunities different from the adult patient. We present a nonconsecutive series of 14 patients temporarily stabilized with percutaneous pedicle screw fixation for injuries including 3-column fracture dislocations and purely ligamentous injuries. Temporary fusionless instrumentation can provide successful management of select thoracolumbar spine injuries in pediatric trauma patients. Level IV-Retrospective case series.

Selection of finite-element mesh parameters in modeling the growth of hydraulic fracturing cracks

NASA Astrophysics Data System (ADS)

Kurguzov, V. D.

2016-12-01

The effect of the mesh geometry on the accuracy of solutions obtained by the finite-element method for problems of linear fracture mechanics is investigated. The guidelines have been formulated for constructing an optimum mesh for several routine problems involving elements with linear and quadratic approximation of displacements. The accuracy of finite-element solutions is estimated based on the degree of the difference between the calculated stress-intensity factor (SIF) and its value obtained analytically. In problems of hydrofracturing of oil-bearing formation, the pump-in pressure of injected water produces a distributed load on crack flanks as opposed to standard fracture mechanics problems that have analytical solutions, where a load is applied to the external boundaries of the computational region and the cracks themselves are kept free from stresses. Some model pressure profiles, as well as pressure profiles taken from real hydrodynamic computations, have been considered. Computer models of cracks with allowance for the pre-stressed state, fracture toughness, and elastic properties of materials are developed in the MSC.Marc 2012 finite-element analysis software. The Irwin force criterion is used as a criterion of brittle fracture and the SIFs are computed using the Cherepanov-Rice invariant J-integral. The process of crack propagation in a linearly elastic isotropic body is described in terms of the elastic energy release rate G and modeled using the VCCT (Virtual Crack Closure Technique) approach. It has been found that the solution accuracy is sensitive to the mesh configuration. Several parameters that are decisive in constructing effective finite-element meshes, namely, the minimum element size, the distance between mesh nodes in the vicinity of a crack tip, and the ratio of the height of an element to its length, have been established. It has been shown that a mesh that consists of only small elements does not improve the accuracy of the solution.

[Management of disk displacement with condylar fracture].

PubMed

Yu, Shi-bin; Li, Zu-bing; Yang, Xue-wen; Zhao, Ji-hong; Dong, Yao-jun

2003-07-01

To investigate clinical features of disk displacement during the course of condylar fracture and to explore the techniques of disk reposition and suturation. 32 patients (10 females and 22 males) who had disk displacements with condylar fractures were followed up. Reduction and reposition of the dislocated disks simultaneously with fixation of fractures were performed. 7 patients underwent intermaxillary fixation with elastic bands for 1 to 2 weeks. The occlusions were satisfactory in all cases but one for the reason of ramus height loss. No TMJ symptom was found when examined 3 months post operation. Anterior disk displacements were most occurred with high condylar process fractures. Surgical reposition and suturation of disk play an important role for the later TMJ-function.

Prediction of anthropometric measurements from tooth length--A Dravidian study.

PubMed

Sunitha, J; Ananthalakshmi, R; Sathiya, Jeeva J; Nadeem, Jeddy; Dhanarathnam, Shanmugam

2015-12-01

Anthropometric measurement is essential for identification of both victims and suspects. Often, this data is not readily available in a crime scene situation. The availability of one data set should help in predicting the other. This study was hypothesised on the basis of a correlation and geometry between the tooth length and various body measurements. To correlate face, palm, foot and stature measurements with tooth length. To derive a regression formula to estimate the various measurements from tooth length. The present study was conducted on Dravidian dental students in the age group 18 - 25 with a sample size of 372. All of the dental and physical parameters were measured using standard anthropometric equipments and techniques. The data was analysed using SPSS software and the methods used for statistical analysis were linear regression analysis and Pearson correlation. The parameters (incisor height (IH), face height (FH), palm length (PL), foot length (FL) and stature (S) showed nil to mild correlation (R = 0.2 ≤ 0.4) except for palm length (PL) and foot length (FL). (R>0.6). It is concluded that odontometric data is not a reliable source for estimating the face height (FH), palm length (PL), foot length (FL) and stature (S).

Phase field model of fluid-driven fracture in elastic media: Immersed-fracture formulation and validation with analytical solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santillán, David; Juanes, Ruben; Cueto-Felgueroso, Luis

Propagation of fluid-driven fractures plays an important role in natural and engineering processes, including transport of magma in the lithosphere, geologic sequestration of carbon dioxide, and oil and gas recovery from low-permeability formations, among many others. The simulation of fracture propagation poses a computational challenge as a result of the complex physics of fracture and the need to capture disparate length scales. Phase field models represent fractures as a diffuse interface and enjoy the advantage that fracture nucleation, propagation, branching, or twisting can be simulated without ad hoc computational strategies like remeshing or local enrichment of the solution space. Heremore » we propose a new quasi-static phase field formulation for modeling fluid-driven fracturing in elastic media at small strains. The approach fully couples the fluid flow in the fracture (described via the Reynolds lubrication approximation) and the deformation of the surrounding medium. The flow is solved on a lower dimensionality mesh immersed in the elastic medium. This approach leads to accurate coupling of both physics. We assessed the performance of the model extensively by comparing results for the evolution of fracture length, aperture, and fracture fluid pressure against analytical solutions under different fracture propagation regimes. Thus, the excellent performance of the numerical model in all regimes builds confidence in the applicability of phase field approaches to simulate fluid-driven fracture.« less

Phase field model of fluid-driven fracture in elastic media: Immersed-fracture formulation and validation with analytical solutions

DOE PAGES

Santillán, David; Juanes, Ruben; Cueto-Felgueroso, Luis

2017-04-20

Propagation of fluid-driven fractures plays an important role in natural and engineering processes, including transport of magma in the lithosphere, geologic sequestration of carbon dioxide, and oil and gas recovery from low-permeability formations, among many others. The simulation of fracture propagation poses a computational challenge as a result of the complex physics of fracture and the need to capture disparate length scales. Phase field models represent fractures as a diffuse interface and enjoy the advantage that fracture nucleation, propagation, branching, or twisting can be simulated without ad hoc computational strategies like remeshing or local enrichment of the solution space. Heremore » we propose a new quasi-static phase field formulation for modeling fluid-driven fracturing in elastic media at small strains. The approach fully couples the fluid flow in the fracture (described via the Reynolds lubrication approximation) and the deformation of the surrounding medium. The flow is solved on a lower dimensionality mesh immersed in the elastic medium. This approach leads to accurate coupling of both physics. We assessed the performance of the model extensively by comparing results for the evolution of fracture length, aperture, and fracture fluid pressure against analytical solutions under different fracture propagation regimes. Thus, the excellent performance of the numerical model in all regimes builds confidence in the applicability of phase field approaches to simulate fluid-driven fracture.« less

Procedure for estimating fracture energy from fracture surface roughness

DOEpatents

Williford, Ralph E.

1989-01-01

The fracture energy of a material is determined by first measuring the length of a profile of a section through a fractured surface of the material taken on a plane perpendicular to the mean plane of that surface, then determining the fractal dimensionality of the surface. From this, the yield strength of the material, and the Young's Modulus of that material, the fracture energy is calculated.

Role of anthropometric data in the prediction of 4-stranded hamstring graft size in anterior cruciate ligament reconstruction.

PubMed

Ho, Sean Wei Loong; Tan, Teong Jin Lester; Lee, Keng Thiam

2016-03-01

To evaluate whether pre-operative anthropometric data can predict the optimal diameter and length of hamstring tendon autograft for anterior cruciate ligament (ACL) reconstruction. This was a cohort study that involved 169 patients who underwent single-bundle ACL reconstruction (single surgeon) with 4-stranded MM Gracilis and MM Semi-Tendinosus autografts. Height, weight, body mass index (BMI), gender, race, age and -smoking status were recorded pre-operatively. Intra-operatively, the diameter and functional length of the 4-stranded autograft was recorded. Multiple regression analysis was used to determine the relationship between the anthropometric measurements and the length and diameter of the implanted autografts. The strongest correlation between 4-stranded hamstring autograft diameter was height and weight. This correlation was stronger in females than males. BMI had a moderate correlation with the diameter of the graft in females. Females had a significantly smaller graft both in diameter and length when compared with males. Linear regression models did not show any significant correlation between hamstring autograft length with height and weight (p>0.05). Simple regression analysis demonstrated that height and weight can be used to predict hamstring graft diameter. The following regression equation was obtained for females: Graft diameter=0.012+0.034*Height+0.026*Weight (R2=0.358, p=0.004) The following regression equation was obtained for males: Graft diameter=5.130+0.012*Height+0.007*Weight (R2=0.086, p=0.002). Pre-operative anthropometric data has a positive correlation with the diameter of 4 stranded hamstring autografts but no significant correlation with the length. This data can be utilised to predict the autograft diameter and may be useful for pre-operative planning and patient counseling for graft selection.

Fracture mechanics in fiber reinforced composite materials, taking as examples B/A1 and CRFP

NASA Technical Reports Server (NTRS)

Peters, P. W. M.

1982-01-01

The validity of linear elastic fracture mechanics and other fracture criteria was investigated with laminates of boron fiber reinforced aluminum (R/A1) and of carbon fiber reinforced epoxide (CFRP). Cracks are assessed by fracture strength Kc or Kmax (critical or maximum value of the stress intensity factor). The Whitney and Nuismer point stress criterion and average stress criterion often show that Kmax of fiber composite materials increases with increasing crack length; however, for R/A1 and CFRP the curve showing fracture strength as a function of crack length is only applicable in a small domain. For R/A1, the reason is clearly the extension of the plastic zone (or the damage zone n the case of CFRP) which cannot be described with a stress intensity factor.

Scale Effects in the Flow of a Shear-Thinning Fluid in Geological Fractures

NASA Astrophysics Data System (ADS)

Meheust, Y.; Roques, C.; Le Borgne, T.; Selker, J. S.

2017-12-01

Subsurface flow processes involving non-Newtonian fluids play a major role in many engineering applications, from in-situ remediation to enhanced oil recovery. The fluids of interest in such applications (f.e., polymers in remediation) often present shear-thinning properties, i.e., their viscosity decreases as a function of the local shear rate. We investigate how fracture wall roughness impacts the flow of a shear-thinning fluid. Numerical simulations of flow in 3D geological fractures are carried out by solving a modified Navier-Stokes equation incorporating the Carreau viscous-shear model. The numerical fractures consist of two isotropic self-affine surfaces which are correlated with each other above a characteristic scale (thecorrelation length of Méheust et al. PAGEOPH 2003). Perfect plastic closing is assumed when the surfaces are in contact. The statistical parameters describing a fracture are the standard deviation of the wall roughness, the mean aperture, the correlation length, and the fracture length, the Hurst exponent being fixed (equal to 0.8). The objective is to investigate how varying the correlation length impacts the flow behavior, for different degrees of closure, and how this behavior diverges from what is known for Newtonian fluids. The results from the 3D simulations are also compared to 2D simulations based on the lubrication theory, which we have developed as an extension of the Reynolds equation for Newtonian fluids. These 2D simulations run orders of magnitude faster, which allows considering a significant statistics of fractures of identical statistical parameters, and therefore draw general conclusions despite the large stochasticity of the media. We also discuss the implications of our results for solute transport by such flows. References:Méheust, Y., & Schmittbuhl, J. (2003). Scale effects related to flow in rough fractures. Pure and Applied Geophysics, 160(5-6), 1023-1050.

Fracture-fault network characterization of pavement imagery of the Whitby Mudstone, Yorkshire

NASA Astrophysics Data System (ADS)

Boersma, Quinten; Hardebol, Nico; Houben, Maartje; Barnhoorn, Auke; Drury, Martyn

2015-04-01

Natural fractures play an important role in the hydrocarbon production from tight reservoirs. The need for fracture network pathways by fraccing matters particularly for shale gas prospects, due to their micro- to nano-darcies matrix permeabilities. The study of natural fractures from outcrops helps to better understand network connectivity and possibility of reactivating pre-existing planes of weakness, induced by hydraulic stimulation. Microseismicity also show that natural fractures are reactivated during fraccing in tight gas reservoirs and influence the success of the stimulation. An accurate understanding of natural fracture networks can help in predicting the development of fracture networks. In this research we analyze an outcrop analogue, the Whitby Mustone Formation (WMF), in terms of its horizontal fracture network. The WMF is the time equivalent of the Posidonia Shale Formation (PSF), which on itself is the main shale gas prospect in the Dutch subsurface. The fracture network of the WMF is characterized by a system of steep dipping joints with two dominant directions with N-S and E-W strike. The network was digitized from bird-view imagery of the pavement with a spatial extent of ~100 m at sub-cm resolution. The imagery is interpreted in terms of orientation and length distributions, intensity and fractal dimensions. Samples from the field were analyzed for rock strength and sample mineralogy. The results indicate that the fracture networks greatly differ per bed. Observed differences are for example; the geometry of the fracture network, its cumulative length distribution law, the fracture intensity, the fracture length vs its orientation and the fractal dimension. All these parameters greatly influence fracture network connectivity, the probability that longer fractures exist within the pavement and whether the network is more prone to clustering or scattering. Apart from the differences, the networks display a fairly similar orthogonal arrangement with dominant large (> 5-10 m) N-S striking fractures and smaller E-W striking cross-joints (< 2-3 m). A nested network arrangement is indicated by some smaller-scale N-S fractures abutting against the E-W striking ones. Furthermore, abutment relations provide some constraints on relative time. Timing indications with respect to burial-exhumation are difficult to establish. Some joints are cemented and measurable from the high-resolution imagery. The vein measurements helped establishing a first order relation between the fracture aperture with respect to their length and confirm that longer fractures have a wider aperture. The above stated parameters and results all prove to be very valuable information which can help predict the geometries of the different fracture networks present within the PSF. It is important to understand the possible mechanisms which can cause these differences in fracture network characteristics. Bulk lithological variations between beds are minor, mainly consisting of clay minerals. Furthermore, some quartz and pyrite is present in all samples and TOC is present in variable amounts. However, the occurrence of concretions up to 0.5m in size correlates with notable differences in distinct network arrangement. Therefore it appears that the presence of these concretions greatly alters the overall strength of the rock, hence the fracture network geometry.

Examination of the pronator quadratus muscle during hardware removal procedures after volar plating for distal radius fractures.

PubMed

Nho, Jae-Hwi; Gong, Hyun Sik; Song, Cheol Ho; Wi, Seung Myung; Lee, Young Ho; Baek, Goo Hyun

2014-09-01

It is not clear whether the pronator quadratus (PQ) muscle actually heals and provides a meaningful pronation force after volar plating for distal radius fractures (DRFs). We aimed to determine whether the length of the PQ muscle, which is dissected and then repaired during volar plating for a DRF, affects the forearm rotation strength and clinical outcomes. We examined 41 patients who requested hardware removal after volar plating. We measured the isokinetic forearm rotation strength and clinical outcomes including grip strength, wrist range of motion, and disabilities of the arm, shoulder and hand (DASH) scores at 6 months after fracture fixation. During the hardware removal surgery, which was performed at an average of 9 months (range, 8.3 to 11.5 months) after fracture fixation, we measured the PQ muscle length. The average PQ muscle length was 68% of the normal muscle length, and no significant relationship was found between the PQ muscle length and the outcomes including isokinetic forearm rotation strength, grip strength, wrist range of motion, and DASH scores. This study demonstrates that the length of the healed PQ muscle does not affect isokinetic forearm rotation strength and clinical outcomes after volar plating for DRFs. The results of this study support our current practice of loose repair of the PQ that is performed by most of the surgeons to prevent tendon irritation over the plate, and suggest that tight repair of the PQ is not necessary for achieving improved forearm function.

The impact of different aperture distribution models and critical stress criteria on equivalent permeability in fractured rocks

NASA Astrophysics Data System (ADS)

Bisdom, Kevin; Bertotti, Giovanni; Nick, Hamidreza M.

2016-05-01

Predicting equivalent permeability in fractured reservoirs requires an understanding of the fracture network geometry and apertures. There are different methods for defining aperture, based on outcrop observations (power law scaling), fundamental mechanics (sublinear length-aperture scaling), and experiments (Barton-Bandis conductive shearing). Each method predicts heterogeneous apertures, even along single fractures (i.e., intrafracture variations), but most fractured reservoir models imply constant apertures for single fractures. We compare the relative differences in aperture and permeability predicted by three aperture methods, where permeability is modeled in explicit fracture networks with coupled fracture-matrix flow. Aperture varies along single fractures, and geomechanical relations are used to identify which fractures are critically stressed. The aperture models are applied to real-world large-scale fracture networks. (Sub)linear length scaling predicts the largest average aperture and equivalent permeability. Barton-Bandis aperture is smaller, predicting on average a sixfold increase compared to matrix permeability. Application of critical stress criteria results in a decrease in the fraction of open fractures. For the applied stress conditions, Coulomb predicts that 50% of the network is critically stressed, compared to 80% for Barton-Bandis peak shear. The impact of the fracture network on equivalent permeability depends on the matrix hydraulic properties, as in a low-permeable matrix, intrafracture connectivity, i.e., the opening along a single fracture, controls equivalent permeability, whereas for a more permeable matrix, absolute apertures have a larger impact. Quantification of fracture flow regimes using only the ratio of fracture versus matrix permeability is insufficient, as these regimes also depend on aperture variations within fractures.

Comparison of computer-assisted surgery with conventional technique for the treatment of axial distal phalanx fractures in horses: an in vitro study.

PubMed

Andritzky, Juliane; Rossol, Melanie; Lischer, Christoph; Auer, Joerg A

2005-01-01

To compare the precision obtained with computer-assisted screw insertion for treatment of mid-sagittal articular fractures of the distal phalanx (P3) with results achieved with a conventional technique. In vitro experimental study. Thirty-two cadaveric equine limbs. Four groups of 8 limbs were studied. Either 1 or 2 screws were inserted perpendicular to an imaginary axial fracture of P3 using computer-assisted surgery (CAS) or conventional technique. Screw insertion time, predetermined screw length, inserted screw length, fit of the screw, and errors in placement were recorded. CAS technique took 15-20 minutes longer but resulted in greater precision of screw length and placement compared with the conventional technique. Improved precision in screw insertion with CAS makes insertion of 2 screws possible for repair of mid-sagittal P3 fractures. CAS although expensive improves precision in screw insertion into P3 and consequently should yield improved clinical outcome.

Modeling the influence of snow cover temperature and water content on wet-snow avalanche runout

NASA Astrophysics Data System (ADS)

Valero, Cesar Vera; Wever, Nander; Christen, Marc; Bartelt, Perry

2018-03-01

Snow avalanche motion is strongly dependent on the temperature and water content of the snow cover. In this paper we use a snow cover model, driven by measured meteorological data, to set the initial and boundary conditions for wet-snow avalanche calculations. The snow cover model provides estimates of snow height, density, temperature and liquid water content. This information is used to prescribe fracture heights and erosion heights for an avalanche dynamics model. We compare simulated runout distances with observed avalanche deposition fields using a contingency table analysis. Our analysis of the simulations reveals a large variability in predicted runout for tracks with flat terraces and gradual slope transitions to the runout zone. Reliable estimates of avalanche mass (height and density) in the release and erosion zones are identified to be more important than an exact specification of temperature and water content. For wet-snow avalanches, this implies that the layers where meltwater accumulates in the release zone must be identified accurately as this defines the height of the fracture slab and therefore the release mass. Advanced thermomechanical models appear to be better suited to simulate wet-snow avalanche inundation areas than existing guideline procedures if and only if accurate snow cover information is available.

War, forced displacement and growth in Laotian adults.

PubMed

Clarkin, Patrick F

2012-01-01

Evidence from several populations suggests that war negatively impacts civilian nutrition, physical growth and overall health. This effect is often enduring or permanent, particularly if experienced early in life. To assess whether the number of lifetime displacement experiences and being displaced in infancy were associated with adult height, sitting height, leg length and the sitting height ratio. Retrospective questionnaires on displacement and resettlement experiences and anthropometric data were collected from a sample of Laotian adult refugees (ethnic Hmong and Lao; n = 365). All were born in Laos or Thailand and had resettled in French Guiana or the US. Many had been displaced several times by military conflict in Laos. In bivariate analyses, being displaced in infancy and the number of lifetime displacement experiences one had were negatively associated with final adult height and leg length in both sexes. The association was stronger in females, particularly Hmong females. There was no significant association between total displacement experiences and the sitting height ratio. In multiple regression analyses, linear growth in males was negatively associated with being displaced in infancy; in females, the number of lifetime displacement experiences was a significant predictor. Forced displacement from war appears to have a lasting effect on final adult height, sitting height and leg length, although not necessarily on the sitting height ratio in this sample.

Hindfoot Valgus following Interlocking Nail Treatment for Tibial Diaphysis Fractures: Can the Fibula Be Neglected?

PubMed Central

Uzun, Metin; Kara, Adnan; Adaş, Müjdat; Karslioğlu, Bülent; Bülbül, Murat; Beksaç, Burak

2014-01-01

Purpose. We evaluated whether intramedullary nail fixation for tibial diaphysis fractures with concomitant fibula fractures (except at the distal one-third level) managed conservatively with an associated fibula fracture resulted in ankle deformity and assessed the impact of the ankle deformity on lower extremity function. Methods. Sixty middle one-third tibial shaft fractures with associated fibular fractures, except the distal one-third level, were included in this study. All tibial shaft fractures were anatomically reduced and fixed with interlocking intramedullary nails. Fibular fractures were managed conservatively. Hindfoot alignment was assessed clinically. Tibia and fibular lengths were compared to contralateral measurements using radiographs. Functional results were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Foot and Ankle Disability Index Score (FADI). Results. Anatomic union, defined as equal length in operative and contralateral tibias, was achieved in 60 fractures (100%). Fibular shortening was identified in 42 fractures (68%). Mean fibular shortening was 1.2 cm (range, 0.5–2 cm). Clinical exams showed increased hindfoot valgus in 42 fractures (68%). The mean KOOS was 88.4, and the mean FADI score was 90. Conclusion. Fibular fractures in the middle or proximal one-third may need to be stabilized at the time of tibial intramedullary nail fixation to prevent development of hindfoot valgus due to fibular shortening. PMID:25544899

Periprosthetic hip fractures: A review of the economic burden based on length of stay.

PubMed

Lyons, Rebecca F; Piggott, Robert P; Curtin, William; Murphy, Colin G

2018-03-01

With the increasing rates of total hip replacements being performed worldwide, there is an increasing incidence of periprosthetic fractures. As our patients' demographics change to include older patients with multiple medical co-morbidities, there is a concurrent increase in morbidity and mortality rates. This leads to longer hospital stays and increasing hospital costs. In the current economic climate, the cost of treating periprosthetic fractures must be addressed and appropriate resource and funding allocation for future provision of services should be planned. All periprosthetic hip fractures that were admitted to a single trauma unit over a three-year period were reviewed. Independent chart review, haematological and radiological review was undertaken. All patients with a periprosthetic fracture associated with a total hip arthroplasty or hemiarthroplasty were included. Follow up data including complications were collated. Data from the hospital inpatient database and finance department was utilized for cost analysis. All statistical analysis was preformed using Minitab version 17. 48 patients were identified who met the inclusion criteria for review. The majority of participants were female with a mean age of 73.5 years. The mean time to fracture was 4.5 years (9 months-18.5 years). Periprosthetic fracture was associated with total hip arthroplasty in 24 cases and a Vancouver B2 classification was most common at n = 20. The majority of patients had revision arthroplasty, with a mean length of stay of 24 days for the whole cohort (9-42). Vancouver B3 fractures had the longest inpatient stay at a mean of 26 days. The mean cost of for a full revision of stem with additional plate and cable fixation was over €27000 compared to €14,600 for ORIF and cable fixation based on length of hospital stay. The prolonged length of stay associated with Vancouver B2 and B3 fractures leads to increased costs to the healthcare service. Accurately calculating the costs of total treatment for periprosthetic fractures is difficult due to a lack of transparency around implant and staffing costs. However, as we can expect increasing incidence of periprosthetic fractures presenting in the coming years it is paramount that we make financial provisions within healthcare budgets to ensure we can treat these patients appropriately.

A variable mixing-length ratio for convection theory

NASA Technical Reports Server (NTRS)

Chan, K. L.; Wolff, C. L.; Sofia, S.

1981-01-01

It is argued that a natural choice for the local mixing length in the mixing-length theory of convection has a value proportional to the local density scale height of the convective bubbles. The resultant variable mixing-length ratio (the ratio between the mixing length and the pressure scale height) of this theory is enhanced in the superadiabatic region and approaches a constant in deeper layers. Numerical tests comparing the new mixing length successfully eliminate most of the density inversion that typically plagues conventional results. The new approach also seems to indicate the existence of granular motion at the top of the convection zone.

Relationship of lifestyle and body stature growth with the development of myopia and axial length elongation in Taiwanese elementary school children.

PubMed

Huang, Chung-Ying; Hou, Chiun-Ho; Lin, Ken-Kuo; Lee, Jiahn-Shing; Yang, Meng-Ling

2014-08-01

The development of myopia and growth of the eye, occur at a time when body stature is increasing. To investigate the relationship of lifestyle and body growth with axial elongation and myopia development among schoolchildren aged 7 to 9 years. Prospective study. Children in elementary schools without serious eye disorders were invited to participate. We measured cycloplegic refraction, corneal curvature, intraocular pressure, axial length, body height, and weight. Questionnaires about the children's daily lifestyles, family members' myopia and parents' socio-demographic status were completed. The children were followed up every 6 months in a 3-year period. Bivariate correlations, simple and multiple regression. Eighty-eight children participated in this study. Forty-eight were myopic at the beginning of the study, and their myopia correlated with longer axial length and parental myopia (P = 0.015, 0.012). Sixty-five children (74%) completed the study, and the rates of change per year were -0.43 ± 0.58 (mean + standard deviation) diopters in spherical equivalence, 0.32 ± 0.25 mm in axial length (AL), 5.73 ± 2.71 cm in body height, and 3.84 ± 2.23 kg in weight. The axial length change was positively correlated with the height change (P < 0.001). The myopia shift was correlated to axial length change (P = 0.000) but not correlated to height change. Using multiple regression test, near work was the only significant risk factor for myopia progression (P = 0.022). Our study showed that body height increment was correlated to axial length elongation but not to myopia shift in children aged 7-9 years. Genetic factors such as parental myopia and body height had a possible influence on myopia development, and the environment factor as near work intensity was related to myopia progression.

Effectiveness of external fixator combined with T-plate internal fixation for the treatment of comminuted distal radius fractures.

PubMed

Han, L R; Jin, C X; Yan, J; Han, S Z; He, X B; Yang, X F

2015-03-31

This study compared the efficacy between external fixator combined with palmar T-plate internal fixation and simple plate internal fixation for the treatment of comminuted distal radius fractures. A total of 61 patients classified as type C according to the AO/ASIF classification underwent surgery for comminuted distal radius fractures. There were 54 and 7 cases of closed and open fractures, respectively. Moreover, 19 patients received an external fixator combined with T-plate internal fixation, and 42 received simple plate internal fixation. All patients were treated successfully during 12-month postoperative follow-up. The follow-up results show that the palmar flexion and dorsiflexion of the wrist, radial height, and palmar angle were significantly better in those treated with the external fixator combined with T-plate compared to those treated with the simple plate only (P < 0.05); however, there were no significant differences in radial-ulnar deviation, wrist range of motion, or wrist function score between groups (P > 0.05). Hence, the effectiveness of external fixator combined with T-plate internal fixation for the treatment of comminuted distal radius fractures was satisfactory. Patients sufficiently recovered wrist, forearm, and hand function. In conclusion, compared to the simple T-plate, the external fixator combined with T-plate internal fixation can reduce the possibility of the postoperative re-shifting of broken bones and keep the distraction of fractures to maintain radial height and prevent radial shortening.

A study of damage zones or characteristic lengths as related to the fracture behavior of graphite/epoxy laminates

NASA Technical Reports Server (NTRS)

Yeow, Y. T.; Brinson, H. F.

1977-01-01

Uniaxial tensile tests conducted on a variety of graphite/epoxy laminates, containing narrow rectangular slits, square or circular holes with various aspect ratios are discussed. The techniques used to study stable crack or damage zone growth--namely, birefringence coatings, COD gages, and microscopic observations are discussed. Initial and final fracture modes are discussed as well as the effect of notch size and shape, and laminate type on the fracture process. Characteristic lengths are calculated and compared to each other using the point, average and inherent flaw theories. Fracture toughnesses are calculated by the same theories and compared to a boundary integral equation technique. Finite width K-calibration factors are also discussed.

Lifted Turbulent Jet Flames

DTIC Science & Technology

1993-04-14

flame length L simultaneously with h, and measuring the visible radiation I simultaneously with h. L(t) was found to be nearly uncorrelated with h(t...variation of 7i/2 /76 with ýh. These experiments included measuring the flame length L simultaneously with h, and measuring the visible radiation I...Measurements of Liftoff Height and Flame Length ... 66 4.5 Simultaneous Measurements of Liftoff Height and Radiation ....... 71 4.6 D scussion

Internal fracture heterogeneity in discrete fracture network modelling: Effect of correlation length and textures with connected and disconnected permeability field

NASA Astrophysics Data System (ADS)

Frampton, A.; Hyman, J.; Zou, L.

2017-12-01

Analysing flow and transport in sparsely fractured media is important for understanding how crystalline bedrock environments function as barriers to transport of contaminants, with important applications towards subsurface repositories for storage of spent nuclear fuel. Crystalline bedrocks are particularly favourable due to their geological stability, low advective flow and strong hydrogeochemical retention properties, which can delay transport of radionuclides, allowing decay to limit release to the biosphere. There are however many challenges involved in quantifying and modelling subsurface flow and transport in fractured media, largely due to geological complexity and heterogeneity, where the interplay between advective and dispersive flow strongly impacts both inert and reactive transport. A key to modelling transport in a Lagrangian framework involves quantifying pathway travel times and the hydrodynamic control of retention, and both these quantities strongly depend on heterogeneity of the fracture network at different scales. In this contribution, we present recent analysis of flow and transport considering fracture networks with single-fracture heterogeneity described by different multivariate normal distributions. A coherent triad of fields with identical correlation length and variance are created but which greatly differ in structure, corresponding to textures with well-connected low, medium and high permeability structures. Through numerical modelling of multiple scales in a stochastic setting we quantify the relative impact of texture type and correlation length against network topological measures, and identify key thresholds for cases where flow dispersion is controlled by single-fracture heterogeneity versus network-scale heterogeneity. This is achieved by using a recently developed novel numerical discrete fracture network model. Furthermore, we highlight enhanced flow channelling for cases where correlation structure continues across intersections in a network, and discuss application to realistic fracture networks using field data of sparsely fractured crystalline rock from the Swedish candidate repository site for spent nuclear fuel.

Anthropometric evaluation of pediatric patients with nonprogressive chronic encephalopathy according to different methods of classification☆

PubMed Central

Teixeira, Jéssica Socas; Gomes, Mirian Martins

2014-01-01

Objective: To perform anthropometric assessment of patients with quadriplegic, chronic non-progressive encephalopathy, comparing two distinct references of nutritional classification and to compare the estimated height to the length measured by stadiometer. Method: Cross-sectional study including 0-3-year children with quadriplegic chronic non-progressive encephalopathy in secondary public hospital. Length, weight, arm circumference, triceps skinfold and knee height were measured. The arm muscle circumference and estimated height were calculated. The following relations were evaluated: weight-for-age, length-for-age and weight-for-length, using as reference the charts of the World Health Organization (WHO) and those proposed by Krick et al. Results: Fourteen children with a mean age of 21 months were evaluated. Assessment of anthropometric indicators showed significant difference between the two classification methods to assess nutritional indicators length/age (p=0.014), weight/age (p=0.014) and weight/length (p=0.001). There was significant correlation between measured length and estimated height (r=0.796, p=0.001). Evaluation of arm circumference and triceps skinfold showed that most patients presented some degree of malnutrition. According to arm muscle circumference, most were eutrophic. Conclusions: Specific curves for children with chronic non-progressive encephalopathy appear to underestimate malnutrition when one takes into account indicators involving weight. Curves developed for healthy children can be a good option for clinical practice and weight-for-length indicator and body composition measurements should be considered as complementary tools. PMID:25479849

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rybicki, E.F.; Luiskutty, C.T.; Sutrick, J.S.

This User's Manual contains information for four fracture/proppant models. TUPROP1 contains a Geertsma and de Klerk type fracture model. The section of the program utilizing the proppant fracture geometry data from the pseudo three-dimensional highly elongated fracture model is called TUPROPC. The analogous proppant section of the program that was modified to accept fracture shape data from SA3DFRAC is called TUPROPS. TUPROPS also includes fracture closure. Finally there is the penny fracture and its proppant model, PENNPROP. In the first three chapters, the proppant sections are based on the same theory for determining the proppant distribution but have modifications tomore » support variable height fractures and modifications to accept fracture geometry from three different fracture models. Thus, information about each proppant model in the User's Manual builds on information supplied in the previous chapter. The exception to the development of combined treatment models is the penny fracture and its proppant model. In this case, a completely new proppant model was developed. A description of how to use the combined treatment model for the penny fracture is contained in Chapter 4. 2 refs.« less

Stress-dependent permeability and ground displacement during CO2 storage operation at KB-502 injection well, In Salah, Algeria

NASA Astrophysics Data System (ADS)

Rinaldi, A.; Rutqvist, J.

2012-12-01

The In Salah CO2 storage project (a joint venture among Statoil, BP, and Sonatrach) is one of the most important sites for understanding the geomechanics associated with carbon dioxide injection. InSAR data evaluated for the first years of injection show a ground-surface uplift of 5 to 10 mm per year at each of the injection wells. A double-lobe uplift pattern has been observed at KB-502, and both semi-analytical inverse deformation analysis (Vasco et al., 2010) and coupled numerical modeling of fluid flow and geomechanics (Rutqvist et al., 2011) have shown that this pattern of displacement can be explained by injection-induced deformation in a deep vertical fracture zone of fault, whose presence has been confirmed by recent 3D seismic survey (Gibson-Poole et al., 2010). Recently, Rinaldi and Rutqvist (2012) refined the previous modeling results, through the use of TOUGH-FLAC (Rutqvist et al., 2002), in order to more conclusively constrain the height of the fracture zone. Results were well in agreement with all available field observations, including all time evolutions and the shape of surface deformation, time-evolution of injection pressure, and the 3D seismic indications of the CO2 saturated fracture zone extending thousands of meters laterally. However, the analysis included a number of simplifications and uncertainties, such as time-step changes in aquifer permeability and the use of an elastic model, which preclude a good match with field data after shut in. Here we implement a new stress-dependent permeability function, to consider a more realistic changes in reservoir and fracture zone permeability, and to improve the match between field observations and modeling results, considering both the bottomhole pressure and the ground surface displacement. Furthermore, here we extent the length of the simulation to include modeling of the re-injection occurred in late 2010 for few months. A second major simplification by Rinaldi and Rutqvist (2012) is the assumption of fracture zone that could have opened instantaneously. Here we present also some early, simple study on potential fracture propagations coupled with stress-dependent permeability changes.

Subtalar distraction osteogenesis for posttraumatic arthritis following intra-articular calcaneal fractures.

PubMed

Fan, Wei-Li; Sun, Hong-Zhen; Wu, Si-Yu; Wang, Ai-Min

2013-03-01

The most common treatment for old calcaneal fractures accompanied by subtalar joint injury is the use of subtalar in situ arthrodesis and subtalar distraction bone-block arthrodesis or osteotomy. This article describes the introduction of a novel surgical treatment, gradual subtalar distraction with external fixation and restoration of the calcaneal height, and presents an assessment of its efficacy. The protruding lateral calcaneus and the articular surfaces and subchondral bone of the posterior facet of the subtalar joint were surgically removed. An external fixator, attached with 2 pins in the subcutaneous tibia and 2 pins in the posterolateral calcaneus, was used to fix the subtalar joint for 7 to 10 days followed by gradual subtalar distraction at 1 mm/d. The lengthening procedure was stopped when the calcaneal height was restored according to radiography. The external fixator was removed after bone fusion. Seven cases of old calcaneal fractures accompanied by severe subtalar joint injury (8 feet) were treated using this method. Average follow-up was 14.3 months (range, 7-36 months). In all 7 cases (1 case of both feet), the postoperative wound healed primarily. The calcaneal heights of all 8 feet were partially restored. Subtalar joint bone fusion was completed within 4 to 6 months after the operation. The average preoperative American Orthopedic Foot & Ankle Society (AOFAS) hindfoot score was 25.3, and the average postoperative AOFAS score was 76.3. Subtalar distraction osteogenesis with external fixation was a novel and effective method for the treatment of old calcaneal fractures accompanied by severe subtalar joint injury in this small group of patients. Level IV, retrospective case series.

Spatial analysis of extension fracture systems: A process modeling approach

USGS Publications Warehouse

Ferguson, C.C.

1985-01-01

Little consensus exists on how best to analyze natural fracture spacings and their sequences. Field measurements and analyses published in geotechnical literature imply fracture processes radically different from those assumed by theoretical structural geologists. The approach adopted in this paper recognizes that disruption of rock layers by layer-parallel extension results in two spacing distributions, one representing layer-fragment lengths and another separation distances between fragments. These two distributions and their sequences reflect mechanics and history of fracture and separation. Such distributions and sequences, represented by a 2 ?? n matrix of lengthsL, can be analyzed using a method that is history sensitive and which yields also a scalar estimate of bulk extension, e (L). The method is illustrated by a series of Monte Carlo experiments representing a variety of fracture-and-separation processes, each with distinct implications for extension history. Resulting distributions of e (L)are process-specific, suggesting that the inverse problem of deducing fracture-and-separation history from final structure may be tractable. ?? 1985 Plenum Publishing Corporation.

Non-local damage rheology and size effect

NASA Astrophysics Data System (ADS)

Lyakhovsky, V.

2011-12-01

We study scaling relations controlling the onset of transiently-accelerating fracturing and transition to dynamic rupture propagation in a non-local damage rheology model. The size effect is caused principally by growth of a fracture process zone, involving stress redistribution and energy release associated with a large fracture. This implies that rupture nucleation and transition to dynamic propagation are inherently scale-dependent processes. Linear elastic fracture mechanics (LEFM) and local damage mechanics are formulated in terms of dimensionless strain components and thus do not allow introducing any space scaling, except linear relations between fracture length and displacements. Generalization of Weibull theory provides scaling relations between stress and crack length at the onset of failure. A powerful extension of the LEFM formulation is the displacement-weakening model which postulates that yielding is complete when the crack wall displacement exceeds some critical value or slip-weakening distance Dc at which a transition to kinetic friction is complete. Scaling relations controlling the transition to dynamic rupture propagation in slip-weakening formulation are widely accepted in earthquake physics. Strong micro-crack interaction in a process zone may be accounted for by adopting either integral or gradient type non-local damage models. We formulate a gradient-type model with free energy depending on the scalar damage parameter and its spatial derivative. The damage-gradient term leads to structural stresses in the constitutive stress-strain relations and a damage diffusion term in the kinetic equation for damage evolution. The damage diffusion eliminates the singular localization predicted by local models. The finite width of the localization zone provides a fundamental length scale that allows numerical simulations with the model to achieve the continuum limit. A diffusive term in the damage evolution gives rise to additional damage diffusive time scale associated with the structural length scale. The ratio between two time scales associated with damage accumulation and diffusion, the damage diffusivity ratio, reflects the role of the diffusion-controlled delocalization. We demonstrate that localized fracturing occurs at the damage diffusivity ratio below certain critical value leading to a linear scaling between stress and crack length compatible with size effect for failures at crack initiation. A subseuqent quasi-static fracture growth is self-similar with increasing size of the process zone proportional to the fracture length. At a certain stage, controlled by dynamic weakening, the self-similarity breaks down and crack velocity significantly deviates from that predicted by the quasi-static regime, the size of the process zone decreases, and the rate of crack growth ceases to be controlled by the rate of damage increase. Furthermore, the crack speed approaches that predicted by the elasto-dynamic equation. The non-local damage rheology model predicts that the nucleation size of the dynamic fracture scales with fault zone thickness distance of the stress interraction.

Subsequent Vertebral Fractures Post Cement Augmentation of the Thoracolumbar Spine: Does it Correlate With Level-specific Bone Mineral Density Scores?

PubMed

Hey, Hwee Weng Dennis; Hwee Weng, Dennis Hey; Tan, Jun Hao; Jun, Hao Tan; Tan, Chuen Seng; Chuen, Seng Tan; Tan, Hsi Ming Bryan; Ming, Bryan Tan Hsi; Lau, Puang Huh Bernard; Huh, Bernard Lau Puang; Hee, Hwan Tak; Hwan, Tak Hee

2015-12-01

A case-control study. In this study, we investigated the correlation between level-specific preoperative bone mineral density and subsequent vertebral fractures. We also identified factors associated with subsequent vertebral fractures. Complications of cement augmentation of the spine include subsequent vertebral fractures, leading to unnecessary morbidity and more treatment. Ability to predict at-risk vertebra will help guide management. We studied all patients with osteoporotic compression fractures who underwent cement augmentation in a single institution from November 2001 to December 2010 by a single surgeon. Association between level-specific bone mineral density T-scores and subsequent fractures was assessed. Multivariable analysis was performed to identify significant factors associated with subsequent vertebral fractures. 93 patients followed up for a mean duration of 25.1 months (12-96) had a mean age of 76.8 years (47-99). Vertebroplasty was performed in 58 patients (62.4%) on 68 levels and kyphoplasty in 35 patients (37.6%) on 44 levels. Refracture was seen in 16 patients (17.2%). The time to subsequent fracture post cement augmentation was 20.5 months (2-90). For refracture cases, 43.8% (7/16) fractured in the adjacent vertebrae. Subsequently fractured vertebra had a mean T-score of -2.860 (95% confidence interval -3.268 to -2.452) and nonfractured vertebra had a mean T-score of -2.180 (95% confidence interval -2.373 to -1.986). A T-score of -2.2 or lower is predictive of refracture at that vertebra (P = 0.047). Odds ratio increases with decreasing T-scores from -2.2 or lower to -2.6 or lower. A T-score of -2.6 or lower gives no additional predictive advantage. After multivariable analysis, age (P = 0.049) and loss of preoperative anterior vertebral height (P = 0.017) are associated with refracture. Level-specific T-scores are predictive of subsequent fractures and the odds ratio increases with lower T-scores from -2.2 or less to -2.6 or less. They have a low positive predictive value, but a high negative predictive value for subsequent fractures. Other significant associations with subsequent refractures include age and anterior vertebral height. 4.

Concomitant upper limb fractures and short-term functional recovery in hip fracture patients: does the site of upper limb injury matter?

PubMed

Di Monaco, Marco; Castiglioni, Carlotta; Vallero, Fulvia; Di Monaco, Roberto; Tappero, Rosa

2015-05-01

The aim of this study was to evaluate functional recovery in a subgroup of hip fracture patients who sustained a simultaneous fracture at the upper limb, taking into account the site of upper limb injury. Of 760 patients admitted consecutively to the authors' rehabilitation hospital because of a fall-related hip fracture, 700 were retrospectively investigated. Functional outcome was assessed using Barthel Index scores. In 49 of the 700 patients, a single fall resulted in both a hip fracture and a fracture of either wrist (n = 34) or proximal humerus (n = 15). The patients with concomitant shoulder fractures had lower median Barthel Index scores after rehabilitation (70 vs. 90, P = 0.003), lower median Barthel Index effectiveness (57.1 vs. 76.9, P = 0.018), and prolonged median length of stay (42 vs. 36 days, P = 0.011) than did the patients with isolated hip fractures. Significant differences persisted after adjustment for six potential confounders. The adjusted odds ratio for achieving a Barthel Index score lower than 85 was 6.71 (95% confidence interval, 1.68-26.81; P = 0.007) for the patients with concomitant shoulder fractures. Conversely, no prognostic disadvantages were associated with concomitant wrist fractures. Data show a worse functional recovery and a prolonged length of stay in the subgroup of hip fracture patients who sustained a concomitant fracture at the proximal humerus, but not at the wrist.

[Home falls in infants before walking acquisition].

PubMed

Claudet, I; Gurrera, E; Honorat, R; Rekhroukh, H; Casasoprana, A; Grouteau, E

2013-05-01

Minor head trauma is frequent among infants and leads to numerous visits to emergency departments for neurological assessment to evaluate the value of cerebral CT scan with the risk for traumatic brain injuries (TBI). To analyze the epidemiological characteristics of nonwalking infants admitted after falling at home and to analyze associated factors for skull fractures and TBI. Between January 2007 and December 2011, all children aged 9 months or younger and admitted after a home fall to the pediatric emergency unit of a tertiary children's hospital were included. The data collected were age, sex, weight and height, body mass index; geographic origin, referral or direct admission, mode of transportation; month, day and time of admission; causes of the fall, alleged fall height, presence of an eyewitness, type of landing surface; Glasgow Coma Scale (GCS) score, application of the head trauma protocol, location and type of injuries, cerebral CT scan results, length of hospital stay, progression, and neglect or abuse situations. DESCRIPTIVE ANALYSIS: within the study period, 1910 infants were included. Fifty-four percent of children were aged less than 6 months with a slight male prevalence (52%). Falls from parental bed and infant carriers accounted for the most frequent fall circumstances. GCS score on admission was equal to 14 or 15 in 99% of cases. A cerebral CT scan was performed in 34% of children and detected 104 skull fractures and 55 TBI. Infants aged less than 1 month had the highest rate of TBI (8.5%). Eleven percent of patients were hospitalized. A situation of abuse was identified in 51 infants (3%). UNIVARIATE ANALYSIS: Male children and infants aged less than 3 months had a higher risk of skull fractures (P = 0.03 and P = 0.0003, respectively). In the TBI group, children were younger (3.8 ± 2.6 months versus 5.4 ± 2.5 months, P < 0.0001), fell from a higher height (90.2 ± 29.5 cm versus 70.9 ± 28.7 cm, P < 0.0001), were more often admitted on a weekend or day off, and had more skull fractures (54% versus 6%, P < 0.001). MULTIVARIATE ANALYSIS: all variables showing P < 0.2 in the univariate analysis were entered into the model. In the final model, three variables continued to be associated with a risk of TBI: being referred by a physician (OR 4.6 [2.2-9.6], P < 0.0001), being younger than 3 months old (OR 3.1 [1.7-5.7], P = 0.0002), falling from a height greater than 90 cm (OR 3.1 [1.7-5.6], P = 0.0002). Before walking acquisition, children are particularly vulnerable and have the highest rate of TBI after a vertical fall. In this age group, the rate of abuse is also higher. Given this double risk, numerous cerebral CT scans are performed (35-40% of the target population). This protocol, however, leads to a low proportion of detected TBI (<10%) compared to the high number of CT scans and an additional risk of irradiation. As no validated predictive score exists and pending the contribution of the S-100B protein assay, the identification of infants at high risk for TBI and justifying neuroimaging is based on the search for predisposing factors and circumstances. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Estimating the hydraulic conductivity of two-dimensional fracture networks

NASA Astrophysics Data System (ADS)

Leung, C. T.; Zimmerman, R. W.

2010-12-01

Most oil and gas reservoirs, as well as most potential sites for nuclear waste disposal, are naturally fractured. In these sites, the network of fractures will provide the main path for fluid to flow through the rock mass. In many cases, the fracture density is so high as to make it impractical to model it with a discrete fracture network (DFN) approach. For such rock masses, it would be useful to have recourse to analytical, or semi-analytical, methods to estimate the macroscopic hydraulic conductivity of the fracture network. We have investigated single-phase fluid flow through stochastically generated two-dimensional fracture networks. The centres and orientations of the fractures are uniformly distributed, whereas their lengths follow either a lognormal distribution or a power law distribution. We have considered the case where the fractures in the network each have the same aperture, as well as the case where the aperture of each fracture is directly proportional to the fracture length. The discrete fracture network flow and transport simulator NAPSAC, developed by Serco (Didcot, UK), is used to establish the “true” macroscopic hydraulic conductivity of the network. We then attempt to match this conductivity using a simple estimation method that does not require extensive computation. For our calculations, fracture networks are represented as networks composed of conducting segments (bonds) between nodes. Each bond represents the region of a single fracture between two adjacent intersections with other fractures. We assume that the bonds are arranged on a kagome lattice, with some fraction of the bonds randomly missing. The conductance of each bond is then replaced with some effective conductance, Ceff, which we take to be the arithmetic mean of the individual conductances, averaged over each bond, rather than over each fracture. This is in contrast to the usual approximation used in effective medium theories, wherein the geometric mean is used. Our explanation is that the conductivities of the bonds that meet at a given node in a fracture network do not satisfy the usual assumption of being uncorrelated; rather, the conductances of at least two of these bonds are highly correlated, as they represent the incoming and outgoing branches of the same fracture. The effective conductance of our idealized “equivalent network” is then trivial to calculate. We find that this estimate of the hydraulic conductivity agrees very closely with the numerically computed value, essentially for all fracture densities that are not too close to the percolation threshold. Moreover, the same methodology applies regardless of whether the fracture lengths are distributed lognormally, or according to a power law.

Longitudinal Fracture Analysis of a Two-Dimensional Functionally Graded Beam

NASA Astrophysics Data System (ADS)

Rizov, V.

2017-11-01

Longitudinal fracture in a two-dimensional functionally graded beam is analyzed. The modulus of elasticity varies continuously in the beam cross-section. The beam is clamped in its right-hand end. The external loading consists of one longitudinal force applied at the free end of the lower crack arm. The longitudinal crack is located in the beam mid-plane. The fracture is studied in terms of the strain energy release rate. The solution derived is used to elucidate the effects of material gradients along the height as well as along the width of the beam cross-section on the fracture behaviour. The results obtained indicate that the fracture in two-dimensional functionally graded beams can be regulated efficiently by employing appropriate material gradients.

Radiologic Changes by Early Motion in Neck Fractures of the Fifth Metacarpal Treated with Antegrade Intramedullary Fixation.

PubMed

Heo, Youn Moo; Kim, Sang Bum; Yi, Jin Woong; Kim, Tae Gyun; Lim, Byoung Gu

2016-02-01

As intramedullary (IM) fixation is one of the fixation methods used in neck fractures of the fifth metacarpal, an early motion of injured finger can be allowed. The purpose of this study is to evaluate whether immediate active motion affects the stability of antegrade IM fixation in surgical treatment of neck fractures of the fifth metacarpal bone and to assess related factors. Thirty one patients treated by closed reduction and antegrade IM fixation were consecutively enrolled. All patients started active motion of the little finger since 7 postoperative days and only daily activities including writing, typing or washing were allowed until the union of fracture. All fractures were healed within four to eight weeks. The changes of angulation, fifth metacarpal length and tip to head distance of K-wire were compared between immediate postoperative radiographs and radiographs at eight weeks. In addition, the effects by age, gender, initial angulation and comminution of the metacarpal neck were assessed. The average change of angulation was 0.12°, 5th metacarpal length was 1.49mm and tip to head distance of K-wire was 1.31mm. There was no significant difference in the change of angulation (p = 0.137). But, there were significant differences in the change of 5th metacarpal length and tip to head distance of K-wire ([Formula: see text]). The change of angulation was related to a comminution of the metacarpal neck and that of 5th metacarpal length was related to age and sex. The change of 5th metacarpal length and tip to head distance of K-wire can occur by an early mobilization in the antegrade IM fixation for neck fractures of the fifth metacarpal. However, we thought that an early active motion after surgery is important to increase the patients' satisfaction, even though careful selection of candidates is necessary.

[Nutritional status in children with intellectual disabilities based on anthropometric profile].

PubMed

Cossio-Bolaños, Marco; Vidal-Espinoza, Rubén; Lagos-Luciano, Juan; Gómez-Campos, Rossana

2015-01-01

Anthropometric variables such as weight, height and body length in children and adolescents with and without intellectual disabilities should be studied in connection with nutritional status, physical growth and biological maturation. a) to analyze the anthropometric profile based on nutritional status, b) to determine the prevalence of overweight and short stature c) to propose equations for predicting height from anthropometric variables. A total of 49 children and adolescents with intellectual disabilities, and from a special education school were studied (30 boys and 19 girls). Weight, height, trunk-cephalic height, forearm and foot length were evaluated. The calculation of nutritional status resulted in the establishment of nutritional categories: underweight, normal and overweight. The anthropometric profile of males varies significantly when classified according to nutritional categories (P<.05); however no variations were observed in the girls (P>.05). Also, high values of overweight prevalence were observed in both genders (43% of boys and 26% of girls). Variables such as age, weight, length of the forearm in females, and foot length in males are good predictors of height (R(2) = 91-94% males and R(2) = 87% females). A high percentage of overweight cases were observed; therefore, rigorous control and monitoring of nutritional status are suggested. The proposed regression equations could be an option in schools to easily and simply predict height. Copyright © 2015. Publicado por Elsevier España, S.L.U.

50 CFR 216.175 - Requirements for monitoring and reporting.

Code of Federal Regulations, 2011 CFR

2011-10-01

...., FFG, DDG, or CG). (G) Length of time observers maintained visual contact with marine mammal. (H) Wave... height in feet (high, low and average during exercise). (I) Narrative description of sensors and... sensor. (F) Length of time observers maintained visual contact with marine mammal. (G) Wave height. (H...

High rates of death and hospitalization follow bone fracture among hemodialysis patients

PubMed Central

Tentori, Francesca; McCullough, Keith; Kilpatrick, Ryan D.; Bradbury, Brian D.; Robinson, Bruce M.; Kerr, Peter G.; Pisoni, Ronald L.

2013-01-01

Altered bone structure and function contribute to the high rates of fractures in dialysis patients compared to the general population. Fracture events may increase the risk of subsequent adverse clinical outcomes. Here we assessed incidence of post-fracture morbidity and mortality in an international cohort of 34, 579 in-center hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS). We estimated country-specific rates of fractures requiring a hospital admission and associated length of stay in the hospital. Incidence rates of death and of a composite event of death/re-hospitalization were estimated for the 1-year post-fracture. Overall, 3% of participants experienced a fracture. Fracture incidence varied across countries, from 12 events/1000 patient year (p-y) in Japan to 45/1000 p-y in Belgium. In all countries, fracture rates were higher in the hemodialysis group compared to those reported for the general population. Median length of stay ranged from 7 to 37 days in the United States and Japan, respectively. In most countries, post-fracture mortality rates exceeded 500/1000 p-y and death/re-hospitalization rates exceeded 1500/1000 p-y. Fracture patients had higher unadjusted rates of death (3.7- fold) and death/re-hospitalization (4.0-fold) compared to the overall DOPPS population. Mortality and hospitalization rates were highest in the first month after the fracture and declined thereafter. Thus, the high frequency of fractures and increased adverse outcomes following a fracture pose a significant health burden for dialysis patients. Fracture prevention strategies should be identified and applied broadly in nephrology practices. PMID:23903367

FracPaQ: a MATLAB™ Toolbox for the Quantification of Fracture Patterns

NASA Astrophysics Data System (ADS)

Healy, D.; Rizzo, R. E.; Cornwell, D. G.; Timms, N.; Farrell, N. J.; Watkins, H.; Gomez-Rivas, E.; Smith, M.

2016-12-01

The patterns of fractures in deformed rocks are rarely uniform or random. Fracture orientations, sizes, shapes and spatial distributions often exhibit some kind of order. In detail, there may be relationships among the different fracture attributes e.g. small fractures dominated by one orientation, larger fractures by another. These relationships are important because the mechanical (e.g. strength, anisotropy) and transport (e.g. fluids, heat) properties of rock depend on these fracture patterns and fracture attributes. This presentation describes an open source toolbox to quantify fracture patterns, including distributions in fracture attributes and their spatial variation. Software has been developed to quantify fracture patterns from 2-D digital images, such as thin section micrographs, geological maps, outcrop or aerial photographs or satellite images. The toolbox comprises a suite of MATLAB™ scripts based on published quantitative methods for the analysis of fracture attributes: orientations, lengths, intensity, density and connectivity. An estimate of permeability in 2-D is made using a parallel plate model. The software provides an objective and consistent methodology for quantifying fracture patterns and their variations in 2-D across a wide range of length scales. Our current focus for the application of the software is on quantifying the fracture patterns in and around fault zones. There is a large body of published work on the quantification of relatively simple joint patterns, but fault zones present a bigger, and arguably more important, challenge. The method presented is inherently scale independent, and a key task will be to analyse and integrate quantitative fracture pattern data from micro- to macro-scales. Planned future releases will incorporate multi-scale analyses based on a wavelet method to look for scale transitions, and combining fracture traces from multiple 2-D images to derive the statistically equivalent 3-D fracture pattern.

Mechanical stratigraphic controls on natural fracture spacing and penetration

NASA Astrophysics Data System (ADS)

McGinnis, Ronald N.; Ferrill, David A.; Morris, Alan P.; Smart, Kevin J.; Lehrmann, Daniel

2017-02-01

Fine-grained low permeability sedimentary rocks, such as shale and mudrock, have drawn attention as unconventional hydrocarbon reservoirs. Fracturing - both natural and induced - is extremely important for increasing permeability in otherwise low-permeability rock. We analyze natural extension fracture networks within a complete measured outcrop section of the Ernst Member of the Boquillas Formation in Big Bend National Park, west Texas. Results of bed-center, dip-parallel scanline surveys demonstrate nearly identical fracture strikes and slight variation in dip between mudrock, chalk, and limestone beds. Fracture spacing tends to increase proportional to bed thickness in limestone and chalk beds; however, dramatic differences in fracture spacing are observed in mudrock. A direct relationship is observed between fracture spacing/thickness ratio and rock competence. Vertical fracture penetrations measured from the middle of chalk and limestone beds generally extend to and often beyond bed boundaries into the vertically adjacent mudrock beds. In contrast, fractures in the mudrock beds rarely penetrate beyond the bed boundaries into the adjacent carbonate beds. Consequently, natural bed-perpendicular fracture connectivity through the mechanically layered sequence generally is poor. Fracture connectivity strongly influences permeability architecture, and fracture prediction should consider thin bed-scale control on fracture heights and the strong lithologic control on fracture spacing.

Early intravenous ibuprofen decreases narcotic requirement and length of stay after traumatic rib fracture.

PubMed

Bayouth, Lilly; Safcsak, Karen; Cheatham, Michael L; Smith, Chadwick P; Birrer, Kara L; Promes, John T

2013-11-01

Pain control after traumatic rib fracture is essential to avoid respiratory complications and prolonged hospitalization. Narcotics are commonly used, but adjunctive medications such as nonsteroidal anti-inflammatory drugs may be beneficial. Twenty-one patients with traumatic rib fractures treated with both narcotics and intravenous ibuprofen (IVIb) (Treatment) were retrospectively compared with 21 age- and rib fracture-matched patients who received narcotics alone (Control). Pain medication requirements over the first 7 hospital days were evaluated. Mean daily IVIb dose was 2070 ± 880 mg. Daily intravenous morphine-equivalent requirement was 19 ± 16 vs 32 ± 24 mg (P < 0.0001). Daily narcotic requirement was significantly decreased in the Treatment group on Days 3 through 7 (P < 0.05). Total weekly narcotic requirement was significantly less among Treatment patients (P = 0.004). Highest and lowest daily pain scores were lower in the Treatment group (P < 0.05). Hospital length of stay was 4.4 ± 3.4 versus 5.4 ± 2.9 days (P = 0.32). There were no significant complications associated with IVIb therapy. Early IVIb therapy in patients with traumatic rib fractures significantly decreases narcotic requirement and results in clinically significant decreases in hospital length of stay. IVIb therapy should be initiated in patients with traumatic rib fractures to improve patient comfort and reduce narcotic requirement.

[Shortening deformities of the clavicle after diaphyseal clavicular fractures : Influence on patient-oriented assessment of shoulder function].

PubMed

Jubel, A; Schiffer, G; Andermahr, J; Ries, C; Faymonville, C

2016-06-01

The aim of this study was the evaluation of patient-oriented outcome scores for shoulder function and residual complaints after diaphyseal clavicular fractures with respect to shortening deformities. The analysis was based on data of 172 adult patients (mean age 39 ± 14 years) with healed clavicular fractures treated operatively (n = 104) or conservatively (n = 67). The control population consisted of 35 healthy adults without shoulder problems and 25 patients with nonunion after conservative treatment. The subjective estimation of the level of pain was collated on a visual analog scale (VAS 1-100 points), together with the relative Constant and Murley score, the Cologne clavicle score, the disabilities of the arm, shoulder and hand (DASH) score and a bilateral comparison of the length difference of the clavicles. Patients with a clavicular length difference of > 2 cm had significantly (p < 0.001) more pain, a greater loss of mobility and significantly lower values in the scoring system of Constant and Murley, the DASH and Cologne clavicle scores compared to patients with clavicular length differences < 0.5 cm and healthy controls (p < 0.001). The results of this study showed that shortening deformities after clavicular fractures in adults have a large impact on the functional result and patient-oriented outcome scores. The aim of the therapy of diaphyseal clavicular fractures should therefore concentrate on reconstruction of the anatomical length of the clavicle.

Hypoalbuminaemia-a marker of malnutrition and predictor of postoperative complications and mortality after hip fractures.

PubMed

Aldebeyan, Sultan; Nooh, Anas; Aoude, Ahmed; Weber, Michael H; Harvey, Edward J

2017-02-01

Our aim was to determine the effect of hypoalbuminaemia as a marker of malnutrition on the 30-day postoperative complication rate and mortality in patients receiving surgical treatment for hip fractures using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. We analyzed all patients admitted with hip fractures receiving surgical treatment from 2011 to 2013. Patients were dichotomized based on their albumin levels; hypoalbuminaemia (albumin <3.5g/dL), and nonhypoalbuminaemia (albumin >3.5g/dL). Patient demographics, postoperative complications, and length of stay were analysed. Logistic regression analysis was conducted to assess the ability of albumin level for predicting postoperative complications, length of stay, and mortality. A total of 10,117 patients with hip fractures were identified with 5414 patients with normal albumin levels, and 4703 with low albumin. Multivariate analysis showed that when controlling for comorbidities; hypoalbuminaemia alone was a predictor of postoperative complications (death, unplanned intubation, being on a ventilator >48h, sepsis, and blood transfusion), and increased length of stay (6.90±7.23 versus 8.44±8.70, CI 0.64-1.20, P<0.001). Hypoalbuminaemia alone can predict postoperative outcomes in patients with hip fractures. Furthermore, patients with hypoalbuminaemia had a longer hospital length of stay. Further studies are needed to assess whether nutritional support can improve postoperative complications in patients with hypoalbuminaemia. Copyright © 2016 Elsevier Ltd. All rights reserved.

Open versus closed reduction: diacapitular fractures of the mandibular condyle.

PubMed

Chrcanovic, Bruno Ramos

2012-09-01

The purpose of the study was to review the literature regarding the evolution of current thoughts on management of diacapitular fractures (DFs) of the mandibular condyle. An electronic search in PubMed was undertaken in March 2012. The titles and abstracts from these results were read to identify studies within the selection criteria. Eligibility criteria included studies reporting clinical series of DFs, including both animal and human studies, without date or language restrictions. The search strategy initially yielded 108 references. Twenty-eight studies were identified without repetition within the selection criteria. Additional hand-searching of the reference lists of selected studies yielded three additional papers. The current indications for open reduction and internal fixation (ORIF) of DFs described in the literature are: (a) fractures affecting the lateral condyle with reduction of mandibular height; (b) fractures in which the proximal fragment dislocates laterally out of the glenoid fossa, which cannot be reduced by closed or open treatment of another part of the mandibular fracture. The indications for conservative treatment are: (a) fractures that do not shorten the condylar height (a fracture with displacement of the medial parts of the condyle); (b) undisplaced fractures; (c) comminution of the condylar head, when the bony fragments are too small for stable fixation; and (d) fractures in children. As the temporomandibular joint disk plays an important role as a barrier preventing ankylosis, it is important to reposition the disk (if displaced/dislocated) during the surgical treatment of DFs. The lateral pterygoid muscle should never be stripped from the medially displaced fragment because its desinsertion disrupts circulation to the medial bony fragment, and also because this muscle helps to restore the muscle function after surgery. ORIF of selected DFs improves prognosis by anatomical bone and soft tissue recovery when combined with physical therapy. If conducted properly, surgical treatment of DFs is a safe and predictable procedure and yields good results.

Pediatric sports-related lower extremity fractures: hospital length of stay and charges: what is the role of the primary payer?

PubMed

Gao, Yubo; Johnston, Richard C; Karam, Matthew

2010-01-01

The purposes of this study were (a) to evaluate the distribution by primary payer (public vs. private) of U.S. pediatric patients aged 5-18 years who were hospitalized with a sports-related lower extremity fracture and (b) to discern the adjusted mean hospital length of stay and mean charge per day by payer type. Children who were aged 5 to 18 years and had diagnoses of lower extremity fracture and sports-related injury in the 2006 Healthcare Cost and Utilization Project Kids' Inpatient Database were included. Lower extremity fractures are defined as International Classification of Diseases, 9th Revision, Clinical Modification codes 820-829 under Section "Injury and Poisoning (800-999)," while sports-related external cause of injury codes (E-codes) are E886.0, E917.0, and E917.5. Differences in hospital length of stay and cost per day by payer type were assessed via adjusted least square mean analysis. The adjusted mean hospital length of stay was 20% higher for patients with a public payer (2.50 days) versus a private payer (2.08 days). The adjusted mean charge per day differed about 10% by payer type (public, US$7,900; private, US$8,794). Further research is required to identify factors that are associated with different length of stay and mean charge per day by payer type, and explore whether observed differences in hospital length of stay are the result of private payers enhancing patient care, thereby discharging patients in a more efficient manner.

High rates of death and hospitalization follow bone fracture among hemodialysis patients.

PubMed

Tentori, Francesca; McCullough, Keith; Kilpatrick, Ryan D; Bradbury, Brian D; Robinson, Bruce M; Kerr, Peter G; Pisoni, Ronald L

2014-01-01

Altered bone structure and function contribute to the high rates of fractures in dialysis patients compared to the general population. Fracture events may increase the risk of subsequent adverse clinical outcomes. Here we assessed the incidence of post-fracture morbidity and mortality in an international cohort of 34,579 in-center hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS). We estimated country-specific rates of fractures requiring a hospital admission and associated length of stay in the hospital. Incidence rates of death and of a composite event of death/rehospitalization were estimated for 1 year after fracture. Overall, 3% of participants experienced a fracture. Fracture incidence varied across countries, from 12 events/1000 patient-years (PY) in Japan to 45/1000 PY in Belgium. In all countries, fracture rates were higher in the hemodialysis group compared to those reported for the general population. Median length of stay ranged from 7 to 37 days in the United States and Japan, respectively. In most countries, postfracture mortality rates exceeded 500/1000 PY and death/rehospitalization rates exceeded 1500/1000 PY. Fracture patients had higher unadjusted rates of death (3.7-fold) and death/rehospitalization (4.0-fold) compared to the overall DOPPS population. Mortality and hospitalization rates were highest in the first month after the fracture and declined thereafter. Thus, the high frequency of fractures and increased adverse outcomes following a fracture pose a significant health burden for dialysis patients. Fracture prevention strategies should be identified and applied broadly in nephrology practices.

Clinical Effects of Posterior Limited Long-Segment Pedicle Instrumentation for the Treatment of Thoracolumbar Fractures.

PubMed

Liang, Chengmin; Liu, Bin; Zhang, Wei; Yu, Haiyang; Cao, Jie; Yin, Wen

2018-06-01

The purpose of this study was to assess the clinical effects of treating thoracolumbar fractures with posterior limited long-segment pedicle instrumentation (LLSPI). A total of 58 thoracolumbar fracture patients were retrospectively analyzed, including 31 cases that were fixed by skipping the fractured vertebra with 6 screws using LLSPI and 27 cases that were fixed by skipping the fractured vertebra with 4 screws using short-segment pedicle instrumentation (SSPI). Surgery time, blood loss, hospital stay, Oswestry disability index (ODI), neurological function, sagittal kyphotic Cobb angle (SKA), percentage of anterior vertebral height (PAVH), instrumentation failure, and the loss of SKA and PAVH were recorded before and after surgery. No significant differences were observed in either the surgery time or hospital stay (P < 0.05), while there were significant differences in blood loss between the two groups. At the final follow-up, both the ODI and the neurological status were notably improved compared to those at the preoperative state (P < 0.05), but the difference between the two groups was relatively small. Furthermore, the SKA and PAVH were notably improved at the final follow-up compared to postoperative values (P < 0.05), but no significant difference was observed between the two groups. During long-term follow-up, the loss of SKA and PAVH in the LLSPI group was significantly less than that in the SSPI group (P < 0.05). Based on strict criteria for data collection and analysis, the clinical effects of LLSPI for the treatment of thoracolumbar fractures were satisfactory, especially for maintaining the height of the fractured vertebra and reducing the loss of SKA and instrumentation failure rates.

Abnormal Patella Height Based on Insall-Salvati Ratio and its Correlation with Patellar Cartilage Lesions: An Extremity-Dedicated Low-Field Magnetic Resonance Imaging Analysis of 1703 Chinese Cases.

PubMed

Lu, W; Yang, J; Chen, S; Zhu, Y; Zhu, C

2016-09-01

Diagnostic performance of patellar position for patellar cartilage lesions remains unclear. The aim of this study was to assess the abnormal patella height and its correlation with chondral lesions of the patellofemoral joint in China. A total of 1703 consecutive patients who performed knee joint examination using an extremity-dedicated low-field magnetic resonance imaging were enrolled in this study. Patellar cartilage lesions were diagnosed based on the result of magnetic resonance imaging and clinical data. Patella height was defined as the ratio of patellar tendon length to patellar length according to Insall-Salvati index. Patella alta and infera were defined as tendon length/patellar length >1.2 and <0.8, respectively. The total prevalence of patellar cartilage lesions was 38.0%. The prevalence in females was significantly higher than that in males (46.4% vs 28.8%, p < 0.001). Age notably increased the incidence of patellar cartilage lesions (p < 0.001). Logistic regression analysis showed that tendon length/patellar length ratio was significantly correlated with patellar cartilage lesions (odds ratio = 6.380, p < 0.001). Furthermore, patients with cartilage lesions showed significantly higher rates of patella alta and infera (p < 0.001). In addition, receiver operating characteristic curve analysis demonstrated that abnormal patella height had statistical significance in diagnosing cartilage lesions (p < 0.001). However, the area under the curve (0.596; 95% confidence interval: 0.568-0.624) and sensitivity (47.0%) were relatively low, while the specificity was 72.2%. Patients with patellar cartilage lesions have an increased tendon length/patellar length ratio. The abnormal patella height is significantly correlated with chondral lesions and can be used as a potential diagnostic marker. © The Finnish Surgical Society 2015.

[Influence of spinal orthosis on gait and physical functioning in women with postmenopausal osteoporosis].

PubMed

Schmidt, K; Hübscher, M; Vogt, L; Klinkmüller, U; Hildebrandt, H D; Fink, M; Banzer, W

2012-03-01

Osteoporosis is a widespread chronic bone disease leading to an increased risk of bone fractures. The most common clinical consequences are back pain, hyperkyphosis, limitations of physical functioning and activities of daily living as well as reduced quality of life. Furthermore, osteoporosis is associated with decreased strength and deficits of gait and balance, all together resulting in an increased risk of falls and a subsequent aggravation of fracture risk. Besides pharmaceutical and exercise therapy, back orthoses are increasingly being used in the therapy of osteoporosis and rehabilitation after vertebral fractures. Previous studies have shown that wearing a spinal orthosis results in a reduction of pain as well as improvements of posture and back extensor strength. To date there is no study that has evaluated the effects of a spinal orthosis on gait stability and physical functioning in patients with osteoporosis. Therefore the purpose of the present study was to assess the effects of a spinal orthosis on gait and pain-induced limitations of activities of daily living (ADL) in women with osteoporosis. A total of 69 postmenopausal osteoporotic women with and without vertebral fractures were randomly assigned to receive either a spinal orthosis (Thämert Osteo-med intervention group n=35; average age 74 ± 8.3 years, height 158.3 ± 6.3 cm, weight 62.8 ± 9.6 kg, t-score -2.6  ± 1.0, number of vertebral fractures 1.4 ± 2.0) or to a waiting list control group (n= 34, age 74.1 ± 7.7 years, height 159.6 ± 5.9 cm, weight 65.4 ± 11.3 kg, t-score -2.9± 0.8, number of vertebral fractures: 0.9 ± 1.2). The following outcome measures were collected at baseline and at 3 and 6 months follow-up: gait parameters including gait analysis: velocity, stride length and width, double support time (% of gait cycle) and perceived limitations in activities of daily living (numeric rating scale 1-10; 1=best, 10= worst situation). The ANCOVA indicated a significant reduction of the double support time at 6 months in the intervention group (p < 0.05) without a significant influence of the covariate vertebral fractures status. The other parameters remained unchanged (p > 0 .05). Regarding the pain-related ADL limitations there were significant differences in the amount of change over the study period depending on the baseline value. Stratified into terciles (≤ 2.5; 2.6-5.0; >5) patients with initially high values showed a significantly greater reduction in perceived ADL restrictions compared to patients in the lowest tercile (-2.7 ± 2.7 versus 1.5 ± 2.1). The study demonstrated that wearing a spinal orthosis introduced a reduction in double support time associated with a beneficial impact on gait stability. Furthermore, there was a positive effect on pain-related restrictions of ADL evident in women with a high level of limitations at baseline. Besides previously shown reductions in pain, improvements in back extensor strength and correction of posture, the application of a spinal orthosis may induce advantages for gait stability and physical functioning in women with postmenopausal osteoporosis. Future studies should consider a longer follow-up to evaluate possible effects on the risk of falling and fractures.

Fracture process zone in granite

USGS Publications Warehouse

Zang, A.; Wagner, F.C.; Stanchits, S.; Janssen, C.; Dresen, G.

2000-01-01

In uniaxial compression tests performed on Aue granite cores (diameter 50 mm, length 100 mm), a steel loading plate was used to induce the formation of a discrete shear fracture. A zone of distributed microcracks surrounds the tip of the propagating fracture. This process zone is imaged by locating acoustic emission events using 12 piezoceramic sensors attached to the samples. Propagation velocity of the process zone is varied by using the rate of acoustic emissions to control the applied axial force. The resulting velocities range from 2 mm/s in displacement-controlled tests to 2 ??m/s in tests controlled by acoustic emission rate. Wave velocities and amplitudes are monitored during fault formation. P waves transmitted through the approaching process zone show a drop in amplitude of 26 dB, and ultrasonic velocities are reduced by 10%. The width of the process zone is ???9 times the grain diameter inferred from acoustic data but is only 2 times the grain size from optical crack inspection. The process zone of fast propagating fractures is wider than for slow ones. The density of microcracks and acoustic emissions increases approaching the main fracture. Shear displacement scales linearly with fracture length. Fault plane solutions from acoustic events show similar orientation of nodal planes on both sides of the shear fracture. The ratio of the process zone width to the fault length in Aue granite ranges from 0.01 to 0.1 inferred from crack data and acoustic emissions, respectively. The fracture surface energy is estimated from microstructure analysis to be ???2 J. A lower bound estimate for the energy dissipated by acoustic events is 0.1 J. Copyright 2000 by the American Geophysical Union.

Gender and age related differences in foot morphology.

PubMed

Tomassoni, Daniele; Traini, Enea; Amenta, Francesco

2014-12-01

This study has assessed age-related changes of foot morphology for developing appropriate footwear with particular reference to the elderly. Anatomical parameters such as foot length, circumference and height and ankle length, circumference and height were assessed in a sample of males (n=577) and females (n=528) divided into three age groups. The groups included young-adult, aged between 20 and 25 years; adult, aged between 35 and 55 years; and old, aged between 65 and 70 years individuals. In terms of gender differences, in young-adult individuals the sex-related morphological differences observed, are just related to a significantly lower length of foot in females. In adult subjects morphological parameters investigated were significantly lower in females even after normalization for foot length. In old individuals, no differences of the parameters were found after normalization for foot length. Comparative analysis of morphometric data between young-adult and adult individuals revealed that the instep length was smaller in adults. The opposite was observed for the great toe and medial foot arch height. Length of ankle was higher in adult than in young-adult individuals, whereas ankle circumference and height were smaller. In old vs adult individuals foot circumference showed the most relevant age-related differences. Feet anatomy presents specific characteristics in different ages of life. The ideal footwear should take into account these characteristics. This is true primarily for the elderly for minimizing the risk of falls or of other problems related to inappropriate footwear. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Shared genetic determinants of axial length and height in children: the Guangzhou twin eye study.

PubMed

Zhang, Jian; Hur, Yoon-Mi; Huang, Wenyong; Ding, Xiaohu; Feng, Ke; He, Mingguang

2011-01-01

To describe the association between axial length (AL) and height and to estimate the extent to which shared genetic or environmental factors influence this covariance. Study participants were recruited from the Guangzhou Twin Registry. Axial length was measured using partial coherence laser interferometry. Height was measured with the participants standing without shoes. We computed twin pairwise correlations and cross-twin cross-trait correlations between AL and height for monozygotic and dizygotic twins and performed model-fitting analyses using a multivariate Cholesky model. The right eye was arbitrarily selected to represent AL of participants. Five hundred sixty-five twin pairs (359 monozygotic and 206 dizygotic) aged 7 to 15 years were available for analysis. Phenotypic correlation between AL and height was 0.46 but decreased to 0.19 after adjusting for age, sex, and age × sex interaction. Bivariate Cholesky model-fitting analyses revealed that 89% of phenotypic correlation was due to shared genetic factors and 11% was due to shared random environmental factors, which includes measurement error. Covariance of AL and height is largely attributable to shared genes. Given that AL is a key determinant of myopia, further work is needed to confirm gene sharing between myopia and stature.

Current Concepts in the Mandibular Condyle Fracture Management Part II: Open Reduction Versus Closed Reduction

PubMed Central

Yang, Jung-Dug; Chung, Ho-Yun; Cho, Byung-Chae

2012-01-01

In the treatment of mandibular condyle fracture, conservative treatment using closed reduction or surgical treatment using open reduction can be used. Management of mandibular condylar fractures remains a source of ongoing controversy in oral and maxillofacial trauma. For each type of condylar fracture,the treatment method must be chosen taking into consideration the presence of teeth, fracture height, patient'sadaptation, patient's masticatory system, disturbance of occlusal function, and deviation of the mandible. In the past, closed reduction with concomitant active physical therapy conducted after intermaxillary fixation during the recovery period had been mainly used, but in recent years, open treatment of condylar fractures with rigid internal fixation has become more common. The objective of this review was to evaluate the main variables that determine the choice of an open or closed method for treatment of condylar fractures, identifying their indications, advantages, and disadvantages, and to appraise the current evidence regarding the effectiveness of interventions that are used in the management of fractures of the mandibular condyle. PMID:22872831

Concurrent rib and pelvic fractures as an indicator of solid abdominal organ injury.

PubMed

Al-Hassani, Ammar; Afifi, Ibrahim; Abdelrahman, Husham; El-Menyar, Ayman; Almadani, Ammar; Recicar, Jan; Al-Thani, Hassan; Maull, Kimball; Latifi, Rifat

2013-01-01

To study the association of solid organ injuries (SOIs) in patients with concurrent rib and pelvic fractures. Retrospective analysis of prospectively collected data from November 2007 to May 2010. Patients' demographics, mechanism of injury, Injury severity scoring, pelvic fracture, and SOIs were analyzed. Patients with SOIs were compared in rib fractures with and without pelvic fracture. The study included 829 patients (460 with rib fractures ± pelvic fracture and 369 with pelvic fracture alone) with mean age of 35 ± 12.7 years. Motor vehicle crashes (45%) and falls from height (30%) were the most common mechanism of injury. The overall incidence of SOIs in this study was 22% (185/829). Further, 15% of patient with rib fractures had associated pelvic fracture. SOI was predominant in patients with concurrent rib fracture and pelvic fracture compared to ribs or pelvic fractures alone (42% vs. 26% vs. 15%, respectively, p = 0.02). Concurrent multiple rib fractures and pelvic fracture increases the risk of SOI compared to either group alone. Lower RFs and pelvic fracture had higher association for SOI and could be used as an early indicator of the presence of SOIs. Copyright © 2013 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Determinants of Transitional Zone Area and Porosity of the Proximal Femur Quantified In Vivo in Postmenopausal Women.

PubMed

Shigdel, Rajesh; Osima, Marit; Lukic, Marko; Ahmed, Luai A; Joakimsen, Ragnar M; Eriksen, Erik F; Bjørnerem, Åshild

2016-04-01

Bone architecture as well as size and shape is important for bone strength and risk of fracture. Most bone loss is cortical and occurs by trabecularization of the inner part of the cortex. We therefore wanted to identify determinants of the bone architecture, especially the area and porosity of the transitional zone, an inner cortical region with a large surface/matrix volume available for intracortical remodeling. In 211 postmenopausal women aged 54 to 94 years with nonvertebral fractures and 232 controls from the Tromsø Study, Norway, we quantified femoral subtrochanteric architecture in CT images using StrAx1.0 software, and serum levels of bone turnover markers (BTM, procollagen type I N-terminal propeptide and C-terminal cross-linking telopeptide of type I collagen). Multivariable linear and logistic regression analyses were used to quantify associations of age, weight, height, and bone size with bone architecture and BTM, and odds ratio (OR) for fracture. Increasing age, height, and larger total cross-sectional area (TCSA) were associated with larger transitional zone CSA and transitional zone CSA/TCSA (standardized coefficients [STB] = 0.11 to 0.80, p ≤ 0.05). Increasing weight was associated with larger TCSA, but smaller transitional zone CSA/TCSA and thicker cortices (STB = 0.15 to 0.22, p < 0.01). Increasing height and TCSA were associated with higher porosity of the transitional zone (STB = 0.12 to 0.46, p < 0.05). Increasing BTM were associated with larger TCSA, larger transitional zone CSA/TCSA, and higher porosity of each of the cortical compartments (p < 0.01). Fracture cases exhibited larger transitional zone CSA and higher porosity than controls (p < 0.001). Per SD increasing CSA and porosity of the transitional zone, OR for fracture was 1.71 (95% CI, 1.37 to 2.14) and 1.51 (95% CI, 1.23 to 1.85), respectively. Cortical bone architecture is determined mainly by bone size as built during growth and is modified by lifestyle factors throughout life through bone turnover. Fracture cases exhibited larger transitional zone area and porosity, highlighting the importance of cortical bone architecture for fracture propensity. © 2015 American Society for Bone and Mineral Research.

Comparison of high-viscosity cement vertebroplasty and balloon kyphoplasty for the treatment of osteoporotic vertebral compression fractures.

PubMed

Wang, Cheng-hu; Ma, Jin-zhu; Zhang, Chuan-chen; Nie, Lin

2015-01-01

Percutaneous vertebroplasty is a widely used vertebral augmentation procedure for treating osteoporotic vertebral compression fractures (OVCFs). But high cement leakage rate caused by a low-viscosity cement and high injection pressure has limited its general use. Balloon kyphoplasty (BKP) and high-viscosity cement vertebroplasty (HVCV) are 2 modifications of vertebroplasty designed to decrease cement leakage. To assess the safety and efficacy of HVCV compared with BKP. A prospective cohort study. Department of Spine Surgery, an affiliated hospital of a medical university. One hundred seven patients suffering from painful OVCFs were randomly assigned into HVCV or BKP groups. Visual Analog Scale (VAS), Oswestry Disability Index (ODI), cement leakage, and vertebral height restoration were evaluated. All occurring complications and injected cement volumes were recorded. The follow-up time was one year. VAS and ODI scores improved in both groups, and did not differ significantly between the 2 groups. More cement was used in the BKP group than in HVCV group (4.22 vs. 3.31 mL, P < 0.0001). The incidence of cement leakage in the HVCV group was lower than that of the BKP group (13.24% vs 30.56%, P < 0.05). No symptomatic cement leakages occurred in the HVCV group. In the BKP group, one patient experienced discogenic back pain related to a disc leak, and another patient had asymptomatic cement emboli in the lung related to venous leakage. The mean compression rate before the procedure was 29.98% in the HVCV group and 28.67% in the BKP group (P = 0.94). The vertebral height was improved significantly and maintained at one-year follow-up in both groups. BKP was more effective in vertebral height restoration than HVCV (44.87% vs. 23.93%, P < 0.0001). There was one case of a new adjacent vertebral fracture in the HVCV group (2%), and 4 cases of new nonadjacent vertebral fractures in the BKP group (7.84%) (P = 0.18). A single-center and relatively small-sample size study. HVCV and BKP are safe and effective in improving quality of life and relieving pain. HVCV has a lower cement leakage rate, whereas BKP is more effective in vertebral height restoration. Subsequent fractures are not different between the 2 groups.

Randomized clinical trial of implant-supported ceramic-ceramic and metal-ceramic fixed dental prostheses: preliminary results.

PubMed

Esquivel-Upshaw, Josephine F; Clark, Arthur E; Shuster, Jonathan J; Anusavice, Kenneth J

2014-02-01

The aim of this study was to determine the survival rates over time of implant-supported ceramic-ceramic and metal-ceramic prostheses as a function of core-veneer thickness ratio, gingival connector embrasure design, and connector height. An IRB-approved, randomized, controlled clinical trial was conducted as a single-blind pilot study involving 55 patients missing three teeth in either one or two posterior areas. These patients (34 women; 21 men; age range 52-75 years) were recruited for the study to receive a three-unit implant-supported fixed dental prosthesis (FDP). Two implants were placed for each of the 72 FDPs in the study. The implants (Osseospeed, Astra Tech), which were made of titanium, were grit blasted. A gold-shaded, custom-milled titanium abutment (Atlantis, Astra Tech), was secured to each implant body. Each of the 72 FDPs in 55 patients were randomly assigned based on one of the following options: (1) A. ceramic-ceramic (Yttria-stabilized zirconia core, pressable fluorapatite glass-ceramic, IPS e.max ZirCAD, and ZirPress, Ivoclar Vivadent) B. metal-ceramic (palladium-based noble alloy, Capricorn, Ivoclar Vivadent, with press-on leucite-reinforced glass-ceramic veneer, IPS InLine POM, Ivoclar Vivadent); (2) occlusal veneer thickness (0.5, 1.0, and 1.5 mm); (3) curvature of gingival embrasure (0.25, 0.5, and 0.75 mm diameter); and (4) connector height (3, 4, and 5 mm). FDPs were fabricated and cemented with dual-cure resin cement (RelyX, Universal Cement, 3M ESPE). Patients were recalled at 6 months, 1 year, and 2 years. FDPs were examined for cracks, fracture, and general surface quality. Recall exams of 72 prostheses revealed 10 chipping fractures. No fractures occurred within the connector or embrasure areas. Two-sided Fisher's exact tests showed no significant correlation between fractures and type of material system (p = 0.51), veneer thickness (p = 0.75), radius of curvature of gingival embrasure (p = 0.68), and connector height (p = 0.91). Although there were no significant associations between connector height, curvature of gingival embrasure, core/veneer thickness ratio, and material system and the survival probability of implant-supported FDPs with zirconia as a core material, the small number of fractures precludes a definitive conclusion on the dominant controlling factor. © 2013 by the American College of Prosthodontists.

Randomized Clinical Trial of Implant-Supported Ceramic-Ceramic and Metal-Ceramic Fixed Dental Prostheses: Preliminary Results

PubMed Central

Esquivel-Upshaw, Josephine F.; Clark, Arthur E.; Shuster, Jonathan J.; Anusavice, Kenneth J.

2013-01-01

Purpose The aim of this study was to determine the survival rates over time of implant-supported ceramic-ceramic and metal-ceramic prostheses as a function of core-veneer thickness ratio, gingival connector embrasure design, and connector height. Materials and Methods An IRB-approved, randomized, controlled clinical trial was conducted as a single-blind pilot study involving 55 patients missing three teeth in either one or two posterior areas. These patients (34 women; 21 men; age range 52–75 years) were recruited for the study to receive a 3-unit implant-supported fixed dental prosthesis (FDP). Two implants were placed for each of the 72 FDPs in the study. The implants (Osseospeed, Astra Tech), which were made of titanium, were grit blasted. A gold-shaded, custom-milled titanium abutment (Atlantis, Astra Tech), was secured to each implant body. Each of the 72 FDPs in 55 patients were randomly assigned based on one of the following options: (1) A. Material: ceramic-ceramic (Yttria-stabilized zirconia core, pressable fluorapatite glass-ceramic, IPS e.max ZirCAD and ZirPress, Ivoclar Vivadent) B. metal-ceramic (palladium-based noble alloy, Capricorn, Ivoclar Vivadent, with press-on leucite-reinforced glass-ceramic veneer, IPS InLine POM, Ivoclar Vivadent); (2) occlusal veneer thickness (0.5, 1.0, and 1.5 mm); (3) curvature of gingival embrasure (0.25, 0.5, and 0.75 mm diameter); and (4) connector height (3, 4, and 5 mm). FDPs were fabricated and cemented with dual-cure resin cement (RelyX, Universal Cement, 3M ESPE). Patients were recalled at 6 months, 1 year, and 2 years. FDPs were examined for cracks, fracture, and general surface quality. Results Recall exams of 72 prostheses revealed 10 chipping fractures. No fractures occurred within the connector or embrasure areas. Two-sided Fisher’s exact tests showed no significant correlation between fractures and type of material system (p = 0.51), veneer thickness (p = 0.75), radius of curvature of gingival embrasure (p = 0.68), and connector height (p = 0.91). Conclusions Although there were no significant associations between connector height, curvature of gingival embrasure, core/veneer thickness ratio, and material system and the survival probability of implant-supported FDPs with zirconia as a core material, the small number of fractures precludes a definitive conclusion on the dominant controlling factor. PMID:23758092

Phase Field Model of Hydraulic Fracturing in Poroelastic Media: Fracture Propagation, Arrest, and Branching Under Fluid Injection and Extraction

NASA Astrophysics Data System (ADS)

Santillán, David; Juanes, Ruben; Cueto-Felgueroso, Luis

2018-03-01

The simulation of fluid-driven fracture propagation in a porous medium is a major computational challenge, with applications in geosciences and engineering. The two main families of modeling approaches are those models that represent fractures as explicit discontinuities and solve the moving boundary problem and those that represent fractures as thin damaged zones, solving a continuum problem throughout. The latter family includes the so-called phase field models. Continuum approaches to fracture face validation and verification challenges, in particular grid convergence, well posedness, and physical relevance in practical scenarios. Here we propose a new quasi-static phase field formulation. The approach fully couples fluid flow in the fracture with deformation and flow in the porous medium, discretizes flow in the fracture on a lower-dimension manifold, and employs the fluid flux between the fracture and the porous solid as coupling variable. We present a numerical assessment of the model by studying the propagation of a fracture in the quarter five-spot configuration. We study the interplay between injection flow rate and rock properties and elucidate fracture propagation patterns under the leak-off toughness dominated regime as a function of injection rate, initial fracture length, and poromechanical properties. For the considered injection scenario, we show that the final fracture length depends on the injection rate, and three distinct patterns are observed. We also rationalize the system response using dimensional analysis to collapse the model results. Finally, we propose some simplifications that alleviate the computational cost of the simulations without significant loss of accuracy.

Estimation of the hydraulic conductivity of a two-dimensional fracture network using effective medium theory and power-law averaging

NASA Astrophysics Data System (ADS)

Zimmerman, R. W.; Leung, C. T.

2009-12-01

Most oil and gas reservoirs, as well as most potential sites for nuclear waste disposal, are naturally fractured. In these sites, the network of fractures will provide the main path for fluid to flow through the rock mass. In many cases, the fracture density is so high as to make it impractical to model it with a discrete fracture network (DFN) approach. For such rock masses, it would be useful to have recourse to analytical, or semi-analytical, methods to estimate the macroscopic hydraulic conductivity of the fracture network. We have investigated single-phase fluid flow through generated stochastically two-dimensional fracture networks. The centers and orientations of the fractures are uniformly distributed, whereas their lengths follow a lognormal distribution. The aperture of each fracture is correlated with its length, either through direct proportionality, or through a nonlinear relationship. The discrete fracture network flow and transport simulator NAPSAC, developed by Serco (Didcot, UK), is used to establish the “true” macroscopic hydraulic conductivity of the network. We then attempt to match this value by starting with the individual fracture conductances, and using various upscaling methods. Kirkpatrick’s effective medium approximation, which works well for pore networks on a core scale, generally underestimates the conductivity of the fracture networks. We attribute this to the fact that the conductances of individual fracture segments (between adjacent intersections with other fractures) are correlated with each other, whereas Kirkpatrick’s approximation assumes no correlation. The power-law averaging approach proposed by Desbarats for porous media is able to match the numerical value, using power-law exponents that generally lie between 0 (geometric mean) and 1 (harmonic mean). The appropriate exponent can be correlated with statistical parameters that characterize the fracture density.

Minimally invasive reduction and fixation of displaced calcaneal fractures: surgical technique and radiographic analysis.

PubMed

Arastu, Mateen; Sheehan, Brendan; Buckley, Richard

2014-03-01

The optimal treatment of calcaneal fractures is controversial. A specific subgroup of healthy patients has good outcomes with open reduction and internal fixation using an extensile lateral approach. However, there are many patients who do not fit into this category. Consequently, they are either denied surgical intervention or put at significant risk of developing complications as a result of open surgical intervention. Minimally invasive reduction and fixation (MIRF) of calcaneal fractures can restore the height, width, length and shape of the hindfoot in addition to restoring the orientation of the posterior facet of the calcaneus (Böhler's angle). We present a series of 31 patients treated with minimally invasive reduction and fixation technique using threaded K wires and Steinmann pins as an alternative treatment method in patients who are not suitable for open reduction and internal fixation. The mean time to surgery from injury was six days (range one to ten days). The mean duration of surgery was 35 minutes (range 11-52 minutes). The mean followup was 14.9 months (range of seven to 30 months). The mean change in Böhler's angle and length of the calcaneus from intra-operative fixation to final followup were 18.7° and 4.7 mm, respectively. The complication rate was low and there was one case of a superficial wound infection and no cases of deep infection or peroneal impingement in this series. The MIRF technique with the use of threaded K wires has not been previously described in the literature. In our experience, the operative time is short and can be safely performed even in the presence of extensive soft tissue swelling in the immediate period following injury. The infection risk is low and calcaneal morphology was improved and maintained in terms of Böhler's angle. This technique is suitable to be considered in patients who have significant medical co-morbidities (smokers, diabetics, peripheral vascular disease) and in those patients who are not suitable for an extensile lateral approach and internal fixation.

Mechanics of Hydraulic Fractures

NASA Astrophysics Data System (ADS)

Detournay, Emmanuel

2016-01-01

Hydraulic fractures represent a particular class of tensile fractures that propagate in solid media under pre-existing compressive stresses as a result of internal pressurization by an injected viscous fluid. The main application of engineered hydraulic fractures is the stimulation of oil and gas wells to increase production. Several physical processes affect the propagation of these fractures, including the flow of viscous fluid, creation of solid surfaces, and leak-off of fracturing fluid. The interplay and the competition between these processes lead to multiple length scales and timescales in the system, which reveal the shifting influence of the far-field stress, viscous dissipation, fracture energy, and leak-off as the fracture propagates.

A comparison of bone density and bone morphology between patients presenting with hip fractures, spinal fractures or a combination of the two

PubMed Central

2013-01-01

Background Currently it is uncertain how to define osteoporosis and who to treat after a hip fracture. There is little to support the universal treatment of all such patients but how to select those most in need of treatment is not clear. In this study we have compared cortical and trabecular bone status between patients with spinal fractures and those with hip fracture with or without spinal fracture with the aim to begin to identify, by a simple clinical method (spine x-ray), a group of hip fracture patients likely to be more responsive to treatment with current antiresorptive agents. Methods Comparison of convenience samples of three groups of 50 patients, one with spinal fractures, one with a hip fracture, and one with both. Measurements consist of bone mineral density at the lumbar spine, at the four standard hip sites, number, distribution and severity of spinal fractures by the method of Genant, cortical bone thickness at the infero-medial femoral neck site, femoral neck and axis length and femoral neck width. Results Patients with spinal fractures alone have the most deficient bones at both trabecular and cortical sites: those with hip fracture and no spinal fractures the best at trabecular bone and most cortical bone sites: and those with both hip and spinal fractures intermediate in most measurements. Hip axis length and neck width did not differ between groups. Conclusion The presence of the spinal fracture indicates poor trabecular bone status in hip fracture patients. Hip fracture patients without spinal fractures have a bone mass similar to the reference range for their age and gender. Poor trabecular bone in hip fracture patients may point to a category of patient more likely to benefit from therapy and may be indicated by the presence of spinal fractures. PMID:23432767

The effect of a microscale fracture on dynamic capillary pressure of two-phase flow in porous media

NASA Astrophysics Data System (ADS)

Tang, Mingming; Lu, Shuangfang; Zhan, Hongbin; Wenqjie, Guo; Ma, Huifang

2018-03-01

Dynamic capillary pressure (DCP) effects, which is vital for predicting multiphase flow behavior in porous media, refers to the injection rate dependence capillary pressure observed during non-equilibrium displacement experiments. However, a clear picture of the effects of microscale fractures on DCP remains elusive. This study quantified the effects of microscale fractures on DCP and simulated pore-scale force and saturation change in fractured porous media using the multiphase lattice Boltzmann method (LBM). Eighteen simulation cases were carried out to calculate DCP as a function of wetting phase saturation. The effects of viscosity ratio and fracture orientation, aperture and length on DCP and DCP coefficient τ were investigated, where τ refers to the ratio of the difference of DCP and static capillary pressure (SCP) over the rate of wetting-phase saturation change versus time. Significant differences in τ values were observed between unfractured and fractured porous media. The τ values of fractured porous media were 1.1  × 104 Pa ms to 5.68 × 105 Pa ms, which were one or two orders of magnitude lower than those of unfractured porous media with a value of 4 × 106 Pa. ms. A horizontal fracture had greater effects on DCP and τ than a vertical fracture, given the same fracture aperture and length. This study suggested that a microscale fracture might result in large magnitude changes in DCP for two-phase flow.

Rural–urban variations in age at menarche, adult height, leg-length and abdominal adiposity in black South African women in transitioning South Africa

PubMed Central

2018-01-01

Abstract Background: The pre-pubertal socioeconomic environment may be an important determinant of age at menarche, adult height, body proportions and adiposity: traits closely linked to adolescent and adult health. Aims: This study explored differences in age at menarche, adult height, relative leg-length and waist circumference between rural and urban black South African young adult women, who are at different stages of the nutrition and epidemiologic transitions. Subjects and methods: We compared 18–23 year-old black South African women, 482 urban-dwelling from Soweto and 509 from the rural Mpumalanga province. Age at menarche, obstetric history and household socio-demographic and economic information were recorded using interview-administered questionnaires. Height, sitting-height, hip and waist circumference were measured using standardised techniques. Results: Urban and rural black South African women differed in their age at menarche (at ages 12.7 and 14.5 years, respectively). In urban women, a one-year increase in age at menarche was associated with a 0.65 cm and 0.16% increase in height and relative leg-length ratio, respectively. In both settings, earlier age at menarche and shorter relative leg-length were independently associated with an increase in waist circumference. Conclusions: In black South African women, the earlier onset of puberty, and consequently an earlier growth cessation process, may lead to central fat mass accumulation in adulthood. PMID:29557678

Maternal height and length of gestation: does this impact on preterm labour in Asian women?

PubMed

Chan, Ben Chong-Pun; Lao, Terence Tzu-Hsi

2009-08-01

Both maternal height and ethnicity may influence the gestation length, but their independent effect is unclear. This study was performed to examine the relationship between maternal height and gestational length in women with singleton pregnancies in a Chinese and southeast Asian population. A retrospective cohort study was performed on women carrying singleton pregnancies with spontaneous labour in a 48-month period managed under our department to determine the relationship between maternal height, expressed in quartiles, with the mean gestational age and incidence of preterm labour. Of the 16 384 women who delivered within this period, the 25th, 50th and 75th percentile values of maternal height were 153 cm, 156 cm and 160 cm respectively. Excluded from analysis were 6597 women because of multifetal pregnancy, teenage pregnancy (maternal age < or = 19 years old), induction of labour or elective caesarean section, or incomplete data due to no antenatal booking in our hospital. Significant differences were found in the maternal weight and body mass index, incidences of multiparity and smokers, gestational age and birthweight among the four quartiles. There was significantly increased incidence of preterm birth between 32 and 37 weeks gestation in women with shorter stature. In our population, maternal height has an influence on gestational length, and the lower three quartiles was associated with increased odds of labour at > 32 to < 37 weeks. This effect should be taken into consideration in the adoption of international recommendations in obstetric management and intervention.

Radiographic study of the fifth metatarsal for optimal intramedullary screw fixation of Jones fracture.

PubMed

Ochenjele, George; Ho, Bryant; Switaj, Paul J; Fuchs, Daniel; Goyal, Nitin; Kadakia, Anish R

2015-03-01

Jones fractures occur in the relatively avascular metadiaphyseal junction of the fifth metatarsal (MT), which predisposes these fractures to delayed union and nonunion. Operative treatment with intramedullary (IM) screw fixation is recommended in certain cases. Incorrect screw selection can lead to refractures, nonunion, and cortical blowout fractures. A better understanding of the anatomy of the fifth MT could aid in preoperative planning, guide screw size selection, and minimize complications. We retrospectively identified foot computed tomographic (CT) scans of 119 patients that met inclusion criteria. Using interactive 3-dimensional (3-D) models, the following measurements were calculated: MT length, "straight segment length" (distance from the base of the MT to the shaft curvature), and canal diameter. The diaphysis had a lateroplantar curvature where the medullary canal began to taper. The average straight segment length was 52 mm, and corresponded to 68% of the overall length of the MT from its proximal end. The medullary canal cross-section was elliptical rather than circular, with widest width in the sagittal plane and narrowest in coronal plane. The average coronal canal diameter at the isthmus was 5.0 mm. A coronal diameter greater than 4.5 mm at the isthmus was present in 81% of males and 74% of females. To our knowledge, this is the first anatomic description of the fifth metatarsal based on 3-D imaging. Excessive screw length could be avoided by keeping screw length less than 68% of the length of the fifth metatarsal. A greater than 4.5 mm diameter screw might be needed to provide adequate fixation for most study patients since the isthmus of the medullary canal for most were greater than 4.5 mm. Our results provide an improved understanding of the fifth metatarsal anatomy to guide screw diameter and length selection to maximize screw fixation and minimize complications. © The Author(s) 2014.

Vertebral Augmentation with Nitinol Endoprosthesis: Clinical Experience in 40 Patients with 1-Year Follow-up

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anselmetti, Giovanni Carlo, E-mail: gc.anselmetti@fastwebnet.it; Manca, Antonio, E-mail: anto.manca@gmail.com; Marcia, Stefano, E-mail: stemarcia@gmail.com

PurposeThis study was designed to assess the clinical outcomes of patients treated by vertebral augmentation with nitinol endoprosthesis (VNE) to treat painful vertebral compression fractures.MethodsForty patients with one or more painful osteoporotic VCF, confirmed by MRI and accompanied by back-pain unresponsive to a minimum 2 months of conservative medical treatment, underwent VNE at 42 levels. Preoperative and postoperative pain measured with Visual Analog Scale (VAS), disability measured by Oswestry Disability Index (ODI), and vertebral height restoration (measured with 2-dimensional reconstruction CT) were compared at last follow-up (average follow-up 15 months). Cement extravasation, subsequent fractures, and implant migration were recorded.ResultsLong-term follow-up was obtainedmore » in 38 of 40 patients. Both VAS and ODI significantly improved from a median of 8.0 (range 5–10) and 66 % (range 44–88 %) to 0.5 (range 0–8) and 6 % (range 6–66 %), respectively, at 1 year (p < 0.0001). Vertebral height measurements comparing time points increased in a statistically significant manner (ANOVA, p < 0.001). Overall cement extravasation rate was 9.5 %. Discal and venous leakage rates were 7.1 and 0 % respectively. No symptomatic extravasations occurred. Five of 38 (13.1 %) patients experienced new spontaneous, osteoporotic fractures. No device change or migration was observed.ConclusionsVNE is a safe and effective procedure that is able to provide long-lasting pain relief and durable vertebral height gain with a low rate of new fractures and cement leakages.« less

Fracture behavior of hybrid composite laminates

NASA Technical Reports Server (NTRS)

Kennedy, J. M.

1983-01-01

The tensile fracture behavior of 15 center-notched hybrid laminates was studied. Three basic laminate groups were tested: (1) a baseline group with graphite/epoxy plies, (2) a group with the same stacking sequence but where the zero-deg plies were one or two plies of S-glass or Kevlar, and (3) a group with graphite plies but where the zero-deg plies were sandwiched between layers of perforated Mylar. Specimens were loaded linearly with time; load, far field strain, and crack opening displacement (COD) were monitored. The loading was stopped periodically and the notched region was radiographed to reveal the extent and type of damage (failure progression). Results of the tests showed that the hybrid laminates had higher fracture toughnesses than comparable all-graphite laminates. The higher fracture toughness was due primarily to the larger damage region at the ends of the slit; delamination and splitting lowered the stress concentration in the primary load-carrying plies. A linear elastic fracture analysis, which ignored delamination and splitting, underestimated the fracture toughness. For almost all of the laminates, the tests showed that the fracture toughness increased with crack length. The size of the damage region at the ends of the slit and COD measurements also increased with crack length.

Relationships of 35 lower limb muscles to height and body mass quantified using MRI.

PubMed

Handsfield, Geoffrey G; Meyer, Craig H; Hart, Joseph M; Abel, Mark F; Blemker, Silvia S

2014-02-07

Skeletal muscle is the most abundant tissue in the body and serves various physiological functions including the generation of movement and support. Whole body motor function requires adequate quantity, geometry, and distribution of muscle. This raises the question: how do muscles scale with subject size in order to achieve similar function across humans? While much of the current knowledge of human muscle architecture is based on cadaver dissection, modern medical imaging avoids limitations of old age, poor health, and limited subject pool, allowing for muscle architecture data to be obtained in vivo from healthy subjects ranging in size. The purpose of this study was to use novel fast-acquisition MRI to quantify volumes and lengths of 35 major lower limb muscles in 24 young, healthy subjects and to determine if muscle size correlates with bone geometry and subject parameters of mass and height. It was found that total lower limb muscle volume scales with mass (R(2)=0.85) and with the height-mass product (R(2)=0.92). Furthermore, individual muscle volumes scale with total muscle volume (median R(2)=0.66), with the height-mass product (median R(2)=0.61), and with mass (median R(2)=0.52). Muscle volume scales with bone volume (R(2)=0.75), and muscle length relative to bone length is conserved (median s.d.=2.1% of limb length). These relationships allow for an arbitrary subject's individual muscle volumes to be estimated from mass or mass and height while muscle lengths may be estimated from limb length. The dataset presented here can further be used as a normative standard to compare populations with musculoskeletal pathologies. © 2013 Published by Elsevier Ltd.

Relationships of maternal and paternal anthropometry with neonatal body size, proportions and adiposity in an Australian cohort.

PubMed

Pomeroy, Emma; Wells, Jonathan C K; Cole, Tim J; O'Callaghan, Michael; Stock, Jay T

2015-04-01

The patterns of association between maternal or paternal and neonatal phenotype may offer insight into how neonatal characteristics are shaped by evolutionary processes, such as conflicting parental interests in fetal investment and obstetric constraints. Paternal interests are theoretically served by maximizing fetal growth, and maternal interests by managing investment in current and future offspring, but whether paternal and maternal influences act on different components of overall size is unknown. We tested whether parents' prepregnancy height and body mass index (BMI) were related to neonatal anthropometry (birthweight, head circumference, absolute and proportional limb segment and trunk lengths, subcutaneous fat) among 1,041 Australian neonates using stepwise linear regression. Maternal and paternal height and maternal BMI were associated with birthweight. Paternal height related to offspring forearm and lower leg lengths, maternal height and BMI to neonatal head circumference, and maternal BMI to offspring adiposity. Principal components analysis identified three components of variability reflecting neonatal "head and trunk skeletal size," "adiposity," and "limb lengths." Regression analyses of the component scores supported the associations of head and trunk size or adiposity with maternal anthropometry, and limb lengths with paternal anthropometry. Our results suggest that while neonatal fatness reflects environmental conditions (maternal physiology), head circumference and limb and trunk lengths show differing associations with parental anthropometry. These patterns may reflect genetics, parental imprinting and environmental influences in a manner consistent with parental conflicts of interest. Paternal height may relate to neonatal limb length as a means of increasing fetal growth without exacerbating the risk of obstetric complications. © 2014 The Authors American Journal of Physical Anthropology Published by Wiley Periodicals, Inc.

Relationships of maternal and paternal anthropometry with neonatal body size, proportions and adiposity in an Australian cohort

PubMed Central

Pomeroy, Emma; Wells, Jonathan CK; Cole, Tim J; O'Callaghan, Michael; Stock, Jay T

2015-01-01

The patterns of association between maternal or paternal and neonatal phenotype may offer insight into how neonatal characteristics are shaped by evolutionary processes, such as conflicting parental interests in fetal investment and obstetric constraints. Paternal interests are theoretically served by maximizing fetal growth, and maternal interests by managing investment in current and future offspring, but whether paternal and maternal influences act on different components of overall size is unknown. We tested whether parents' prepregnancy height and body mass index (BMI) were related to neonatal anthropometry (birthweight, head circumference, absolute and proportional limb segment and trunk lengths, subcutaneous fat) among 1,041 Australian neonates using stepwise linear regression. Maternal and paternal height and maternal BMI were associated with birthweight. Paternal height related to offspring forearm and lower leg lengths, maternal height and BMI to neonatal head circumference, and maternal BMI to offspring adiposity. Principal components analysis identified three components of variability reflecting neonatal “head and trunk skeletal size,” “adiposity,” and “limb lengths.” Regression analyses of the component scores supported the associations of head and trunk size or adiposity with maternal anthropometry, and limb lengths with paternal anthropometry. Our results suggest that while neonatal fatness reflects environmental conditions (maternal physiology), head circumference and limb and trunk lengths show differing associations with parental anthropometry. These patterns may reflect genetics, parental imprinting and environmental influences in a manner consistent with parental conflicts of interest. Paternal height may relate to neonatal limb length as a means of increasing fetal growth without exacerbating the risk of obstetric complications. Am J Phys Anthropol 156:625–636, 2015. PMID:25502164

Evaluation of production tests in oil wells stimulated by massive acid fracturing offshore Qatar

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDonald, S.W.

This paper presents the evaluation of pressure-buildup data from production tests in wells that have been stimulated by massive acid fracturing. Fracture type curves are used in combination with conventional semilog analysis techniques. Fracture characteristics are calculated from a match of the early-time pressure data with the type curves, and reservoir characteristics are calculated from a conventional semilog plot of late-time data. Unexpectedly high formation permeabilities are evaluated, and fracture half-lengths are much shorter than design values.

Advances in Permeable Reactive Barrier Technologies

DTIC Science & Technology

2002-08-01

technical methods, such as jetting and hydraulic fracturing , has improved the ability to access deeper aquifers. Table 1 describes the established and...34, Cape Canaveral Air Station, FL. Hydraulic Fracturing 120 A series of wells are installed along the length of the PRB. A vertical fracture is...especially helpful with deep instal- lation methods, such as hydraulic fracturing , where the barrier installed is just a few inches thick. A second, new type

Application of Reservoir Flow Simulation Integrated with Geomechanics in Unconventional Tight Play

NASA Astrophysics Data System (ADS)

Lin, Menglu; Chen, Shengnan; Mbia, Ernest; Chen, Zhangxing

2018-01-01

Multistage hydraulic fracturing techniques, combined with horizontal drilling, have enabled commercial production from the vast reserves of unconventional tight formations. During hydraulic fracturing, fracturing fluid and proppants are pumped into the reservoir matrix to create the hydraulic fractures. Understanding the propagation mechanism of hydraulic fractures is essential to estimate their properties, such as half-length. In addition, natural fractures are often present in tight formations, which might be activated during the fracturing process and contribute to the post-stimulation well production rates. In this study, reservoir simulation is integrated with rock geomechanics to predict the well post-stimulation productivities. Firstly, a reservoir geological model is built based on the field data collected from the Montney formation in the Western Canadian Sedimentary Basin. The hydraulic fracturing process is then simulated through an integrated approach of fracturing fluid injection, rock geomechanics, and tensile failure criteria. In such a process, the reservoir pore pressure increases with a continuous injection of the fracturing fluid and proppants, decreasing the effective stress exerted on the rock matrix accordingly as the overburden pressure remains constant. Once the effective stress drops to a threshold value, tensile failure of the reservoir rock occurs, creating hydraulic fractures in the formation. The early production history of the stimulated well is history-matched to validate the predicted fracture geometries (e.g., half-length) generated from the fracturing simulation process. The effects of the natural fracture properties and well bottom-hole pressures on well productivity are also studied. It has been found that nearly 40% of hydraulic fractures propagate in the beginning stage (the pad step) of the fracturing schedule. In addition, well post-stimulation productivity will increase significantly if the natural fractures are propped or partially propped by the proppants. This paper provides insights on fracture propagation and can be a reference for fracturing treatments in unconventional tight reservoirs.

Assessing the Causal Relationship of Maternal Height on Birth Size and Gestational Age at Birth: A Mendelian Randomization Analysis.

PubMed

Zhang, Ge; Bacelis, Jonas; Lengyel, Candice; Teramo, Kari; Hallman, Mikko; Helgeland, Øyvind; Johansson, Stefan; Myhre, Ronny; Sengpiel, Verena; Njølstad, Pål Rasmus; Jacobsson, Bo; Muglia, Louis

2015-08-01

Observational epidemiological studies indicate that maternal height is associated with gestational age at birth and fetal growth measures (i.e., shorter mothers deliver infants at earlier gestational ages with lower birth weight and birth length). Different mechanisms have been postulated to explain these associations. This study aimed to investigate the casual relationships behind the strong association of maternal height with fetal growth measures (i.e., birth length and birth weight) and gestational age by a Mendelian randomization approach. We conducted a Mendelian randomization analysis using phenotype and genome-wide single nucleotide polymorphism (SNP) data of 3,485 mother/infant pairs from birth cohorts collected from three Nordic countries (Finland, Denmark, and Norway). We constructed a genetic score based on 697 SNPs known to be associated with adult height to index maternal height. To avoid confounding due to genetic sharing between mother and infant, we inferred parental transmission of the height-associated SNPs and utilized the haplotype genetic score derived from nontransmitted alleles as a valid genetic instrument for maternal height. In observational analysis, maternal height was significantly associated with birth length (p = 6.31 × 10-9), birth weight (p = 2.19 × 10-15), and gestational age (p = 1.51 × 10-7). Our parental-specific haplotype score association analysis revealed that birth length and birth weight were significantly associated with the maternal transmitted haplotype score as well as the paternal transmitted haplotype score. Their association with the maternal nontransmitted haplotype score was far less significant, indicating a major fetal genetic influence on these fetal growth measures. In contrast, gestational age was significantly associated with the nontransmitted haplotype score (p = 0.0424) and demonstrated a significant (p = 0.0234) causal effect of every 1 cm increase in maternal height resulting in ~0.4 more gestational d. Limitations of this study include potential influences in causal inference by biological pleiotropy, assortative mating, and the nonrandom sampling of study subjects. Our results demonstrate that the observed association between maternal height and fetal growth measures (i.e., birth length and birth weight) is mainly defined by fetal genetics. In contrast, the association between maternal height and gestational age is more likely to be causal. In addition, our approach that utilizes the genetic score derived from the nontransmitted maternal haplotype as a genetic instrument is a novel extension to the Mendelian randomization methodology in casual inference between parental phenotype (or exposure) and outcomes in offspring.

Assessing the Causal Relationship of Maternal Height on Birth Size and Gestational Age at Birth: A Mendelian Randomization Analysis

PubMed Central

Zhang, Ge; Bacelis, Jonas; Lengyel, Candice; Teramo, Kari; Hallman, Mikko; Helgeland, Øyvind; Johansson, Stefan; Myhre, Ronny; Sengpiel, Verena; Njølstad, Pål Rasmus; Jacobsson, Bo; Muglia, Louis

2015-01-01

Background Observational epidemiological studies indicate that maternal height is associated with gestational age at birth and fetal growth measures (i.e., shorter mothers deliver infants at earlier gestational ages with lower birth weight and birth length). Different mechanisms have been postulated to explain these associations. This study aimed to investigate the casual relationships behind the strong association of maternal height with fetal growth measures (i.e., birth length and birth weight) and gestational age by a Mendelian randomization approach. Methods and Findings We conducted a Mendelian randomization analysis using phenotype and genome-wide single nucleotide polymorphism (SNP) data of 3,485 mother/infant pairs from birth cohorts collected from three Nordic countries (Finland, Denmark, and Norway). We constructed a genetic score based on 697 SNPs known to be associated with adult height to index maternal height. To avoid confounding due to genetic sharing between mother and infant, we inferred parental transmission of the height-associated SNPs and utilized the haplotype genetic score derived from nontransmitted alleles as a valid genetic instrument for maternal height. In observational analysis, maternal height was significantly associated with birth length (p = 6.31 × 10−9), birth weight (p = 2.19 × 10−15), and gestational age (p = 1.51 × 10−7). Our parental-specific haplotype score association analysis revealed that birth length and birth weight were significantly associated with the maternal transmitted haplotype score as well as the paternal transmitted haplotype score. Their association with the maternal nontransmitted haplotype score was far less significant, indicating a major fetal genetic influence on these fetal growth measures. In contrast, gestational age was significantly associated with the nontransmitted haplotype score (p = 0.0424) and demonstrated a significant (p = 0.0234) causal effect of every 1 cm increase in maternal height resulting in ~0.4 more gestational d. Limitations of this study include potential influences in causal inference by biological pleiotropy, assortative mating, and the nonrandom sampling of study subjects. Conclusions Our results demonstrate that the observed association between maternal height and fetal growth measures (i.e., birth length and birth weight) is mainly defined by fetal genetics. In contrast, the association between maternal height and gestational age is more likely to be causal. In addition, our approach that utilizes the genetic score derived from the nontransmitted maternal haplotype as a genetic instrument is a novel extension to the Mendelian randomization methodology in casual inference between parental phenotype (or exposure) and outcomes in offspring. PMID:26284790

Feline high-rise syndrome: 119 cases (1998-2001).

PubMed

Vnuk, D; Pirkić, B; Maticić, D; Radisić, B; Stejskal, M; Babić, T; Kreszinger, M; Lemo, N

2004-10-01

High-rise syndrome was diagnosed in 119 cats over a 4-year period. 59.6% of cats were younger than one year, and the average height of the fall was four stories. High-rise syndrome was more frequent during the warmer period of the year. 96.5% of the presented cats, survived after the fall. 46.2% of cats had fractured limbs; 38.5% of fractures were of the forelimb, 61.5% of the hindlimb. The tibia was fractured most often (36.4%), followed by the femur (23.6%). 78.6% of femoral fractures were distal. The mean age of patients with femoral fractures was 9.1 months, and with tibial fractures 29.2 months. Thoracic trauma was diagnosed in 33.6% of cats. Pneumothorax was diagnosed in 20% of cats, and pulmonary contusions in 13.4%. Falls from the seventh or higher stories, are associated with more severe injuries and with a higher incidence of thoracic trauma.

Protection against hip fractures by energy absorption.

PubMed

Lauritzen, J B; Askegaard, V

1992-02-01

Impact lateral to the hip was noted in 37 of 60 patients with hip fracture. Women with hip fracture (n = 12) had an average 22 mm thick soft tissue cover of the hip as compared to 32 mm in healthy women (n = 27), even for the same body mass index. Experiments where a steel weight was dropped from various heights onto porcine soft tissue showed that a layer of 29 mm could absorb 60% more energy than a 20 mm thick layer before nearly metallic contact would occur, corresponding to a sharp rise in load. If the results are related to conditions in vivo, then the passive protection of soft tissue over the hip is important for the development of hip fractures, and may under certain assumptions explain the higher risk of hip fractures in thin persons. An external hip protection device might therefore prevent some hip fractures.

50 CFR 660.704 - Vessel identification.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OFF WEST COAST STATES Highly Migratory Fisheries... (25.40 cm) in height for vessels more than 25 ft (7.62 m) but equal to or less than 65 ft (19.81 m) in length; and 18 inches (45.72 cm)in height for vessels longer than 65 ft (19.81 m) in length. Markings...

Traumatic ipsilateral multiple open metatarsal and calcaneal fractures with first metatarsophalangeal joint dislocation: a case report.

PubMed

Ozkan, Namik Kemal; Unay, Koray; Cift, Hakan; Eceviz, Engin; Ozkan, Korhan

2010-06-01

A 17-year-old man fell from a height of 10 m onto his right forefoot and sustained ipsilateral calcaneal, comminuted cuboid, and second, third, and fourth metatarsal neck fractures and first metatarsophalangeal joint open dislocation. This report discusses this rare injury. The authors believe that initial debridement with immediate surgical fixation and reduction with appropriate antibiotic treatment saved the patient's extremity.

Computed tomography of calcaneal fractures: anatomy, pathology, dosimetry, and clinical relevance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guyer, B.H.; Levinsohn, E.M.; Fredrickson, B.E.

1985-11-01

Eighteen CT examinations were performed in 10 patients for the evaluation of acute intraarticular fractures and their follow-up. Fractures comparable to those in the patients were created in cadavers. The normal anatomy and the traumatically altered anatomy of the calcaneus in the axial, coronal, and sagittal planes are demonstrated by CT and corresponding anatomic sections. Scanning was performed in the axial plane, with subsequent reconstruction in the coronal and sagittal planes. The axial scans show disruption of the inferior part of the posterior facet, calcaneocuboid joint involvement, and widening of the calcaneus. The coronal scans show disruption of the superiormore » part of the posterior facet, sustentaculum tali depression (involvement of middle and anterior facets), peroneal and flexor hallucis longus tendon impingement, and widening and height loss of the calcaneus. The sagittal scans show disruption of the posterior facet, calcaneocuboid joint involvement, and height loss of the calcaneus and allow the evaluation of Boehler's and Gissane's angles. All three planes show the position of major fracture fragments. Radiation dose to the foot was measured to be 0.1 rad (0.001 Gy) for plain film radiography (five exposures), 18 rad (0.18 Gy) for conventional tomography (20 cuts), and 2.6 rad (0.026 Gy) for axial CT examination.« less

Characteristic Length Scales in Fracture Networks: Hydraulic Connectivity through Periodic Hydraulic Tests

NASA Astrophysics Data System (ADS)

Becker, M.; Bour, O.; Le Borgne, T.; Longuevergne, L.; Lavenant, N.; Cole, M. C.; Guiheneuf, N.

2017-12-01

Determining hydraulic and transport connectivity in fractured bedrock has long been an important objective in contaminant hydrogeology, petroleum engineering, and geothermal operations. A persistent obstacle to making this determination is that the characteristic length scale is nearly impossible to determine in sparsely fractured networks. Both flow and transport occur through an unknown structure of interconnected fracture and/or fracture zones making the actual length that water or solutes travel undetermined. This poses difficulties for flow and transport models. For, example, hydraulic equations require a separation distance between pumping and observation well to determine hydraulic parameters. When wells pairs are close, the structure of the network can influence the interpretation of well separation and the flow dimension of the tested system. This issue is explored using hydraulic tests conducted in a shallow fractured crystalline rock. Periodic (oscillatory) slug tests were performed at the Ploemeur fractured rock test site located in Brittany, France. Hydraulic connectivity was examined between three zones in one well and four zones in another, located 6 m apart in map view. The wells are sufficiently close, however, that the tangential distance between the tested zones ranges between 6 and 30 m. Using standard periodic formulations of radial flow, estimates of storativity scale inversely with the square of the separation distance and hydraulic diffusivity directly with the square of the separation distance. Uncertainty in the connection paths between the two wells leads to an order of magnitude uncertainty in estimates of storativity and hydraulic diffusivity, although estimates of transmissivity are unaffected. The assumed flow dimension results in alternative estimates of hydraulic parameters. In general, one is faced with the prospect of assuming the hydraulic parameter and inverting the separation distance, or vice versa. Similar uncertainties exist, for instance, when trying to invert transport parameters from tracer mean residence time. This field test illustrates that when dealing with fracture networks, there is a need for analytic methods of complexity that lie between simple radial solutions and discrete fracture network models.

Fracture network evaluation program (FraNEP): A software for analyzing 2D fracture trace-line maps

NASA Astrophysics Data System (ADS)

Zeeb, Conny; Gomez-Rivas, Enrique; Bons, Paul D.; Virgo, Simon; Blum, Philipp

2013-10-01

Fractures, such as joints, faults and veins, strongly influence the transport of fluids through rocks by either enhancing or inhibiting flow. Techniques used for the automatic detection of lineaments from satellite images and aerial photographs, LIDAR technologies and borehole televiewers significantly enhanced data acquisition. The analysis of such data is often performed manually or with different analysis software. Here we present a novel program for the analysis of 2D fracture networks called FraNEP (Fracture Network Evaluation Program). The program was developed using Visual Basic for Applications in Microsoft Excel™ and combines features from different existing software and characterization techniques. The main novelty of FraNEP is the possibility to analyse trace-line maps of fracture networks applying the (1) scanline sampling, (2) window sampling or (3) circular scanline and window method, without the need of switching programs. Additionally, binning problems are avoided by using cumulative distributions, rather than probability density functions. FraNEP is a time-efficient tool for the characterisation of fracture network parameters, such as density, intensity and mean length. Furthermore, fracture strikes can be visualized using rose diagrams and a fitting routine evaluates the distribution of fracture lengths. As an example of its application, we use FraNEP to analyse a case study of lineament data from a satellite image of the Oman Mountains.

Landing on your own two feet: a case report of bilateral calcaneus and open pilon fractures.

PubMed

Tiedeken, Nathan C; Hampton, David; Shaffer, Gene

2014-01-01

High energy fractures of the distal tibial plafond and calcaneus have been associated with high functional morbidity and wound complications. Although both of these fractures result from a similar mechanism, they have rarely been reported to occur on an ipsilateral extremity. The combination of these 2 injuries on the same extremity would increase the likelihood of an adverse surgical or functional outcome. We present the case and management strategy of a 43-year-old male with bilateral open pilon fractures and closed calcaneal fractures after falling from a height. A staged protocol was used for the bilateral pilon fractures, with external fixation until operative fixation on day 9. Nonoperative management of the calcaneal fractures resulted in a successful functional outcome at 10 months of follow-up. Treatment of this fracture pattern must incorporate the condition of the soft tissues, an understanding of the fractures, and minimize patient risk factors to optimize the functional and surgical outcomes. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Predicting diameter at breast height from total height and crown length

Treesearch

Quang V. Cao; Thomas J. Dean

2013-01-01

Tree diameter at breast height (d.b.h.) is often predicted from total height (model 1a) or both total height and number of trees per acre (model 1b). These approaches are useful when Light Detection and Ranging (LiDAR) data are available. LiDAR height data can be employed to predict tree d.b.h., and consequently individual tree volumes and volume/ ha can be obtained...

Intra-annual height increment of Pinus sylvestris at high latitudes in Finland.

PubMed

Salminen, Hannu; Jalkanen, Risto

2007-09-01

Intra-annual height growth of Scots pine (Pinus sylvestris L.) in four stands was followed for up to four growing seasons (2000-2003) in the northern boreal zone in Lapland. Elongation of the leader shoot correlated with temperature sum expressed as degree-days. Total length of the leader shoot correlated with growth rate but not with duration of the height-growth period. The longer the annual shoot at the end of the season, the greater the height increment per degree- and growing day. Height-growth cessation was defined as the date when 95% of the total shoot length was achieved. In all stands and all years, height growth ceased when, on average, 41% of the relative temperature sum of the site was achieved (range of variation 38-43%). The relative temperature sum was calculated by dividing the actual temperature sum by the long-term mean for the site. Our results suggest that annual height growth is finished when a location-specific temperature sum threshold is attained.

FracPaQ: a MATLAB™ toolbox for the quantification of fracture patterns

NASA Astrophysics Data System (ADS)

Healy, David; Rizzo, Roberto; Farrell, Natalie; Watkins, Hannah; Cornwell, David; Gomez-Rivas, Enrique; Timms, Nick

2017-04-01

The patterns of fractures in deformed rocks are rarely uniform or random. Fracture orientations, sizes, shapes and spatial distributions often exhibit some kind of order. In detail, there may be relationships among the different fracture attributes e.g. small fractures dominated by one orientation, larger fractures by another. These relationships are important because the mechanical (e.g. strength, anisotropy) and transport (e.g. fluids, heat) properties of rock depend on these fracture patterns and fracture attributes. This presentation describes an open source toolbox to quantify fracture patterns, including distributions in fracture attributes and their spatial variation. Software has been developed to quantify fracture patterns from 2-D digital images, such as thin section micrographs, geological maps, outcrop or aerial photographs or satellite images. The toolbox comprises a suite of MATLAB™ scripts based on published quantitative methods for the analysis of fracture attributes: orientations, lengths, intensity, density and connectivity. An estimate of permeability in 2-D is made using a parallel plate model. The software provides an objective and consistent methodology for quantifying fracture patterns and their variations in 2-D across a wide range of length scales. Our current focus for the application of the software is on quantifying crack and fracture patterns in and around fault zones. There is a large body of published work on the quantification of relatively simple joint patterns, but fault zones present a bigger, and arguably more important, challenge. The methods presented are inherently scale independent, and a key task will be to analyse and integrate quantitative fracture pattern data from micro- to macro-scales. New features in this release include multi-scale analyses based on a wavelet method to look for scale transitions, support for multi-colour traces in the input file processed as separate fracture sets, and combining fracture traces from multiple 2-D images to derive the statistically equivalent 3-D fracture pattern expressed as a 2nd rank crack tensor.

Current Concepts in the Mandibular Condyle Fracture Management Part I: Overview of Condylar Fracture

PubMed Central

Yang, Jung-Dug; Chung, Ho-Yun; Cho, Byung-Chae

2012-01-01

The incidence of condylar fractures is high, but the management of fractures of the mandibular condyle continues to be controversial. Historically, maxillomandibular fixation, external fixation, and surgical splints with internal fixation systems were the techniques commonly used in the treatment of the fractured mandible. Condylar fractures can be extracapsular or intracapsular, undisplaced, deviated, displaced, or dislocated. Treatment depends on the age of the patient, the co-existence of other mandibular or maxillary fractures, whether the condylar fracture is unilateral or bilateral, the level and displacement of the fracture, the state of dentition and dental occlusion, and the surgeonnds on the age of the patient, the co-existence of othefrom which it is difficult to recover aesthetically and functionally;an appropriate treatment is required to reconstruct the shape and achieve the function ofthe uninjured status. To do this, accurate diagnosis, appropriate reduction and rigid fixation, and complication prevention are required. In particular, as mandibular condyle fracture may cause long-term complications such as malocclusion, particularly open bite, reduced posterior facial height, and facial asymmetry in addition to chronic pain and mobility limitation, great caution should be taken. Accordingly, the authors review a general overview of condyle fracture. PMID:22872830

The influence of pelvic adjustment on vertical jump height in female university students with functional leg length inequality.

PubMed

Gong, Wontae

2015-01-01

[Purpose] This study aimed to investigate the effect of pelvic adjustment on vertical jump height (VJH) in female university students with functional leg length inequality (FLLI). [Subjects] Thirty female university students with FLLI were divided into a pelvic adjustment group (n = 15) and a stretching (control) group (n = 15). [Methods] VJH was measured using an OptoGait. [Results] After the intervention, jump height improved significantly compared with the pre-intervention height only in the pelvic adjustment group, while FLLI showed statistically significant improvement in both groups. [Conclusion] Pelvic adjustment as per the Gonstead method can be applied as a method of reducing FLLI and increasing VJH.

Leg length, body proportion, and health: a review with a note on beauty.

PubMed

Bogin, Barry; Varela-Silva, Maria Inês

2010-03-01

Decomposing stature into its major components is proving to be a useful strategy to assess the antecedents of disease, morbidity and death in adulthood. Human leg length (femur + tibia), sitting height (trunk length + head length) and their proportions, for example, (leg length/stature), or the sitting height ratio (sitting height/stature x 100), among others) are associated with epidemiological risk for overweight (fatness), coronary heart disease, diabetes, liver dysfunction and certain cancers. There is also wide support for the use of relative leg length as an indicator of the quality of the environment for growth during infancy, childhood and the juvenile years of development. Human beings follow a cephalo-caudal gradient of growth, the pattern of growth common to all mammals. A special feature of the human pattern is that between birth and puberty the legs grow relatively faster than other post-cranial body segments. For groups of children and youth, short stature due to relatively short legs (i.e., a high sitting height ratio) is generally a marker of an adverse environment. The development of human body proportions is the product of environmental x genomic interactions, although few if any specific genes are known. The HOXd and the short stature homeobox-containing gene (SHOX) are genomic regions that may be relevant to human body proportions. For example, one of the SHOX related disorders is Turner syndrome. However, research with non-pathological populations indicates that the environment is a more powerful force influencing leg length and body proportions than genes. Leg length and proportion are important in the perception of human beauty, which is often considered a sign of health and fertility.

Leg Length, Body Proportion, and Health: A Review with a Note on Beauty

PubMed Central

Bogin, Barry; Varela-Silva, Maria Inês

2010-01-01

Decomposing stature into its major components is proving to be a useful strategy to assess the antecedents of disease, morbidity and death in adulthood. Human leg length (femur + tibia), sitting height (trunk length + head length) and their proportions, for example, (leg length/stature), or the sitting height ratio (sitting height/stature × 100), among others) are associated with epidemiological risk for overweight (fatness), coronary heart disease, diabetes, liver dysfunction and certain cancers. There is also wide support for the use of relative leg length as an indicator of the quality of the environment for growth during infancy, childhood and the juvenile years of development. Human beings follow a cephalo-caudal gradient of growth, the pattern of growth common to all mammals. A special feature of the human pattern is that between birth and puberty the legs grow relatively faster than other post-cranial body segments. For groups of children and youth, short stature due to relatively short legs (i.e., a high sitting height ratio) is generally a marker of an adverse environment. The development of human body proportions is the product of environmental x genomic interactions, although few if any specific genes are known. The HOXd and the short stature homeobox-containing gene (SHOX) are genomic regions that may be relevant to human body proportions. For example, one of the SHOX related disorders is Turner syndrome. However, research with non-pathological populations indicates that the environment is a more powerful force influencing leg length and body proportions than genes. Leg length and proportion are important in the perception of human beauty, which is often considered a sign of health and fertility. PMID:20617018

Effect of Pin Length on Hook Size and Joint Properties in Friction Stir Lap Welding of 7B04 Aluminum Alloy

NASA Astrophysics Data System (ADS)

Wang, Min; Zhang, Huijie; Zhang, Jingbao; Zhang, Xiao; Yang, Lei

2014-05-01

Friction stir lap welding of 7B04 aluminum alloy was conducted in the present paper, and the effect of pin length on hook size and joint properties was investigated in detail. It is found that for each given set of process parameters, the size of hook defect on the advancing side shows an "M" type evolution trend as the pin length is increased. The affecting characteristics of pin length on joint properties are dependent on the heat input levels. When the heat input is low, the fracture strength is firstly increased to a peak value and then shows a decrease. When the heat input is relatively high, the evolution trend of fracture strength tends to exhibit a "W" type with increasing the pin length.

Abnormal peri-pubertal anthropometric measurements and growth pattern in adolescent idiopathic scoliosis: a study of 598 patients.

PubMed

Siu King Cheung, Catherine; Tak Keung Lee, Warren; Kit Tse, Yee; Ping Tang, Sheng; Man Lee, Kwong; Guo, Xia; Qin, Lin; Chun Yiu Cheng, Jack

2003-09-15

A cross-sectional study of anthropometric parameters in adolescent idiopathic scoliosis (AIS). To compare anthropometric parameters and growth pattern of AIS girls versus normal controls during peri-puberty. Abnormal pattern of growth has been reported in AIS patients. The sequential changes of growth and the correlation with curve severity have not been properly studied. Five hundred ninety-eight AIS girls and 307 healthy girls entered the study. Weight, height, body mass index (BMI), arm span, sitting height, and leg length were determined using standard techniques. Height and sitting height were adjusted by using the greatest Cobb angle to correct for spinal deformity (Bjure's formula). Puberty was graded by Tanner's staging. AIS girls had significantly shorter height (P = 0.001), corrected height (P = 0.005), arm span (P = 0.022), sitting height (P = 0.005) and leg length (P = 0.004) than the controls at pubertal stage I. From pubertal stages II through V, corrected height (P

CHANG-ES. IX. Radio scale heights and scale lengths of a consistent sample of 13 spiral galaxies seen edge-on and their correlations

NASA Astrophysics Data System (ADS)

Krause, Marita; Irwin, Judith; Wiegert, Theresa; Miskolczi, Arpad; Damas-Segovia, Ancor; Beck, Rainer; Li, Jiang-Tao; Heald, George; Müller, Peter; Stein, Yelena; Rand, Richard J.; Heesen, Volker; Walterbos, Rene A. M.; Dettmar, Ralf-Jürgen; Vargas, Carlos J.; English, Jayanne; Murphy, Eric J.

2018-03-01

Aim. The vertical halo scale height is a crucial parameter to understand the transport of cosmic-ray electrons (CRE) and their energy loss mechanisms in spiral galaxies. Until now, the radio scale height could only be determined for a few edge-on galaxies because of missing sensitivity at high resolution. Methods: We developed a sophisticated method for the scale height determination of edge-on galaxies. With this we determined the scale heights and radial scale lengths for a sample of 13 galaxies from the CHANG-ES radio continuum survey in two frequency bands. Results: The sample average values for the radio scale heights of the halo are 1.1 ± 0.3 kpc in C-band and 1.4 ± 0.7 kpc in L-band. From the frequency dependence analysis of the halo scale heights we found that the wind velocities (estimated using the adiabatic loss time) are above the escape velocity. We found that the halo scale heights increase linearly with the radio diameters. In order to exclude the diameter dependence, we defined a normalized scale height h˜ which is quite similar for all sample galaxies at both frequency bands and does not depend on the star formation rate or the magnetic field strength. However, h˜ shows a tight anticorrelation with the mass surface density. Conclusions: The sample galaxies with smaller scale lengths are more spherical in the radio emission, while those with larger scale lengths are flatter. The radio scale height depends mainly on the radio diameter of the galaxy. The sample galaxies are consistent with an escape-dominated radio halo with convective cosmic ray propagation, indicating that galactic winds are a widespread phenomenon in spiral galaxies. While a higher star formation rate or star formation surface density does not lead to a higher wind velocity, we found for the first time observational evidence of a gravitational deceleration of CRE outflow, e.g. a lowering of the wind velocity from the galactic disk.

Decreased fracture rate, pharmacogenetics and BMD response in 79 Swedish children with osteogenesis imperfecta types I, III and IV treated with Pamidronate.

PubMed

Lindahl, K; Kindmark, A; Rubin, C-J; Malmgren, B; Grigelioniene, G; Söderhäll, S; Ljunggren, Ö; Åström, E

2016-06-01

Osteogenesis imperfecta (OI) is an inherited heterogeneous bone fragility disorder, usually caused by collagen I mutations. It is well established that bisphosphonate treatment increases lumbar spine (LS) bone mineral density (BMD), as well as improves vertebral geometry in severe OI; however, fracture reduction has been difficult to prove, pharmacogenetic studies are scarce, and it is not known at which age, or severity of disease, treatment should be initiated. COL1A1 and COL1A2 were analyzed in 79 children with OI (type I n=33, type III n=25 and type IV n=21) treated with Pamidronate. Data on LS BMD, height, and radiologically confirmed non-vertebral and vertebral fractures were collected prior to, and at several time points during treatment. An increase in LS BMD Z-score was observed for all types of OI, and a negative correlation to Δ LS BMD was observed for both age and LS BMD Z-score at treatment initiation. Supine height Z-scores were not affected by Pamidronate treatment, The fracture rate was reduced for all OI types at all time points during treatment (overall p<0.0003, <0.0001 and 0.0003 for all OI types I, III and IV respectively). The reduced fracture rate was maintained for types I and IV, while an additional decrease was observed over time for type III. The fracture rate was reduced also in individuals with continued low BMD after >4yrs Pamidronate. Twice as many boys as girls with OI type I were treated with Pamidronate, and the fracture rate the year prior treatment was 2.2 times higher for boys (p=0.0236). Greater Δ LS BMD, but smaller Δ fracture numbers were observed on Pamidronate for helical glycine mutations in COL1A1 vs. COL1A2. Vertebral compression fractures did not progress in any individual during treatment; however, they did not improve in 9%, and these individuals were all >11years of age at treatment initiation (p<0.0001). Pamidronate treatment in children with all types of OI increased LS BMD, decreased fracture rate, and improved vertebral compression fractures. Fracture reduction was prompt and maintained during treatment, irrespective of age at treatment initiation and collagen I mutation type. Copyright © 2016 Elsevier Inc. All rights reserved.

Prosthetic replacement for proximal humeral fractures.

PubMed

Kontakis, George; Tosounidis, Theodoros; Galanakis, Ioannis; Megas, Panagiotis

2008-12-01

The ideal management of complex proximal humeral fractures continues to be debatable. Evolution of proximal humeral fracture management, during the past decade, led to the implementation of many innovations in surgical treatment. Even though the pendulum of treatment seems to swing towards new trends such as locked plating, hemiarthroplasty remains a valid and reliable option that serves the patient's needs well. Hemiarthroplasty is indicated for complex proximal humeral fractures in elderly patients with poor bone stock and when internal fixation is difficult or unreliable. Hemiarthroplasty provides a better result when it is performed early post-injury. Stem height, retroversion and tuberosity positioning are technical aspects of utmost importance. Additionally reverse total shoulder arthroplasty is an alternative new modality that can be used as a primary solution in selected patients with proximal humeral fracture treatment. Failed hemiarthroplasty and fracture sequelae can be successfully managed with reverse total shoulder arthroplasty. Individual decision-making and tailored treatment that takes into consideration the personality of the fracture and the patient's characteristics should be used.

Is Hospital Teaching Status a Key Factor in Hospital Charge for Children with Hip Fractures?

PubMed Central

Gao, Yubo; Pugely, Andrew; Karam, Matthew; Phisitkul, Phinit; Mendoza, Sergio; Johnston, Richard C.

2013-01-01

OBJECTIVE Proximal femur fractures cause significant pain and economic cost among pediatric patients. The purposes of this study were (a) to evaluate the distribution by hospital type (teaching hospital vs non-teaching hospital) of U.S. pediatric patients aged 1-20 years who were hospitalized with a closed hip fracture and (b) to discern the mean hospital charge and hospital length of stay after employing propensity score to reduce selec-tion bias. METHODS The 2006 Healthcare Cost and Uti-lization Project (HCUP) Kids’ Inpatient Database (KID) was queried for children aged up to 20 years that had principle diagnosis of hip fracture injury. Hip fractures were defined by International Classifi-cation of Diseases, 9th Revision, Clinical Modifica-tion codes 820.0, 820.2 and 820.8 under Section “Injury and Poisoning (800-999)” with principle internal fixation procedure codes 78.55, 79.15 and 79.35. Patient demographics and hospital status were presented and analyzed. Differences in mean hospital charge and hospital length of stay by hospital teaching status were assessed via two propensity score based methods. RESULTS In total, 1,827 patients were nation-ally included for analysis: 1,392 (76.2%) were treated at a teaching hospital and 435 (23.8%) were treated at a non-teaching hospital. The average age of the patients was 12.88 years old in teaching hospitals vs 14.33 years old in nonteaching hospitals. The propensity score based ad-justment method showed mean hospital charge was $34,779 in teaching hospitals and $32,891 in the non-teaching hospitals, but these differences were not significant (p=0.2940). Likewise, mean length of hospital stay was 4.1 days in teaching hospitals and 3.89 days in non-teaching hospitals, but these differences were also not significant (p=0.4220). Conclusions Hospital teaching status did not affect length of stay or total hospital costs in children treated surgically for proximal femur fractures. Future research should be directed at identifying factors associated with variations in hospital charge and length of stay. PMID:24027472

Is hospital teaching status a key factor in hospital charge for children with hip fractures?: preliminary findings from KID database.

PubMed

Gao, Yubo; Pugely, Andrew; Karam, Matthew; Phisitkul, Phinit; Mendoza, Sergio; Johnston, Richard C

2013-01-01

Proximal femur fractures cause significant pain and economic cost among pediatric patients. The purposes of this study were (a) to evaluate the distribution by hospital type (teaching hospital vs non-teaching hospital) of U.S. pediatric patients aged 1-20 years who were hospitalized with a closed hip fracture and (b) to discern the mean hospital charge and hospital length of stay after employing propensity score to reduce selection bias. The 2006 Healthcare Cost and Utilization Project (HCUP) Kids' Inpatient Database (KID) was queried for children aged up to 20 years that had principle diagnosis of hip fracture injury. Hip fractures were defined by International Classification of Diseases, 9th Revision, Clinical Modification codes 820.0, 820.2 and 820.8 under Section "Injury and Poisoning (800-999)" with principle internal fixation procedure codes 78.55, 79.15 and 79.35. Patient demographics and hospital status were presented and analyzed. Differences in mean hospital charge and hospital length of stay by hospital teaching status were assessed via two propensity score based methods. In total, 1,827 patients were nation-ally included for analysis: 1,392 (76.2%) were treated at a teaching hospital and 435 (23.8%) were treated at a non-teaching hospital. The average age of the patients was 12.88 years old in teaching hospitals vs 14.33 years old in nonteaching hospitals. The propensity score based adjustment method showed mean hospital charge was $34,779 in teaching hospitals and $32,891 in the non-teaching hospitals, but these differences were not significant (p=0.2940). Likewise, mean length of hospital stay was 4.1 days in teaching hospitals and 3.89 days in non-teaching hospitals, but these differences were also not significant (p=0.4220). Hospital teaching status did not affect length of stay or total hospital costs in children treated surgically for proximal femur fractures. Future research should be directed at identifying factors associated with variations in hospital charge and length of stay.

Growth reference for Saudi preschool children: LMS parameters and percentiles.

PubMed

Shaik, Shaffi Ahamed; El Mouzan, Mohammad Issa; AlSalloum, Abdullah Abdulmohsin; AlHerbish, Abdullah Sulaiman

2016-01-01

Previous growth charts for Saudi children have not included detailed tables and parameters needed for research and incorporation in electronic records. The objective of this report is to publish the L, M, and S parameters and percentiles as well as the corresponding growth charts for Saudi preschool children. Community-based survey and measurement of growth parameters in a sample selected by a multistage probability procedure. A stratified listing of the Saudi population. Raw data from the previous nationally-representative sample were reanalyzed using the Lambda-Mu-Sigma (LMS) methodology to calculate the L, M, and S parameters of percentiles (from 3rd to 97th) for weight, length/height, head circumference, and body mass index-for-age, and weight for-length/height for boys and girls from birth to 60 months. Length or height and weight of Saudi preschool children. There were 15601 Saudi children younger than 60 months of age, 7896 (50.6 %) were boys. The LMS parameters for weight for age from birth to 60 months (5 years) are reported for the 3rd, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 97th percentiles as well as the corresponding graphs. Similarly, the LMS parameters for length/height-for-age, head circumference-for-age, weight-for-length/height and body mass index-for-age (BMi) are shown with the corresponding graphs for boys and girls. Using the data in this report, clinicians and researchers can assess the growth of Saudi preschool children. The report does not reflect interregional variations in growth.

Microfracture spacing distributions and the evolution of fracture patterns in sandstones

NASA Astrophysics Data System (ADS)

Hooker, J. N.; Laubach, S. E.; Marrett, R.

2018-03-01

Natural fracture patterns in sandstone were sampled using scanning electron microscope-based cathodoluminescence (SEM-CL) imaging. All fractures are opening-mode and are fully or partially sealed by quartz cement. Most sampled fractures are too small to be height-restricted by sedimentary layers. At very low strains (<∼0.001), fracture spatial distributions are indistinguishable from random, whereas at higher strains, fractures are generally statistically clustered. All 12 large (N > 100) datasets show spacings that are best fit by log-normal size distributions, compared to exponential, power law, or normal distributions. The clustering of fractures suggests that the locations of natural factures are not determined by a random process. To investigate natural fracture localization, we reconstructed the opening history of a cluster of fractures within the Huizachal Group in northeastern Mexico, using fluid inclusions from synkinematic cements and thermal-history constraints. The largest fracture, which is the only fracture in the cluster visible to the naked eye, among 101 present, opened relatively late in the sequence. This result suggests that the growth of sets of fractures is a self-organized process, in which small, initially isolated fractures grow and progressively interact, with preferential growth of a subset of fractures developing at the expense of growth of the rest. Size-dependent sealing of fractures within sets suggests that synkinematic cementation may contribute to fracture clustering.

Evaluation of the Edge Crack Torsion (ECT) Test for Mode 3 Interlaminar Fracture Toughness of Laminated Composites

NASA Technical Reports Server (NTRS)

Li, Jian; Lee, Edward W.; OBrien, T. Kevin; Lee, Shaw Ming

1996-01-01

An analytical and experimental investigation was carried out on G40-800/R6376 graphite epoxy laminates to evaluate the Edge Crack Torsion (ECT) test as a candidate for a standard Mode 3 interlaminar fracture toughness test for laminated composites. The ECT test consists of a (90/(+/- 45)(sub 3)/(+/- 45)(sub 3)/90))(sub s) laminate with a delamination introduced by a non-adhesive film at the mid-plane along one edge and loaded in a special fixture to create torsion along the length of the laminate. Dye penetrate enhanced X-radiograph of failed specimens revealed that the delamination initiated at the middle of the specimen length and propagated in a self similar manner along the laminate mid-plane. A three-dimensional finite element analysis was performed that indicated that a pure Mode 3 delamination exists at the middle of specimen length away from both ends. At the ends near the loading point a small Mode 2 component exists. However, the magnitude of this Mode 2 strain energy release rate at the loading point is small compared to the magnitude of Mode 3 component in the mid-section of the specimen. Hence, the ECT test yielded the desired Mode 3 delamination. The Mode 3 fracture toughness was obtained from a compliance calibration method and was in good agreement with the finite element results. Mode 2 End-Notched Flexure (ENF) tests and Mode 1 Double Cantilever Beam (DCB) tests were also performed for the same composite material. The Mode 1 fracture toughness was much smaller than both the Mode 2 and Mode 3 fracture toughness. The Mode 2 fracture toughness was found to be 75% of the Mode 3 fracture toughness.

A new genetic linkage map of barley (Hordeum vulgare L.) facilitates genetic dissection of height and spike length and angle

USDA-ARS?s Scientific Manuscript database

Plant height and spike length and angle are important agronomic traits in the production of barley (Hordeum vulgare L.) due to strong correlations with lodging and disease. The objective of this study was to use QTL analysis to identify genetic regions associated with each trait in a recombinant inb...

46 CFR 28.560 - Watertight and weathertight integrity.

Code of Federal Regulations, 2010 CFR

2010-10-01

... follows: (1) For a vessel 79 feet (24 meters) or more in length, the coaming must be at least 24 inches (0.61 meters) in height; or (2) For a vessel less than 79 feet (24 meters) in length, the coaming must be at least 12 inches (0.30 meters) in height. (c) A coaming to a fish hold that is under constant...

Evaluation of a passive flame-height sensor to estimate forest fire intensity.

Treesearch

Kevin C. Ryan

1981-01-01

The length of flames of wildland fires is a relative indicator of fireline intensity and an important index to fire effects and difficulty of control. A technique for measuring flame height and flame-tilt angle for the purpose of calculating flame length is described. Laboratory tests determined the feasibility of using cotton string treated with ammonium phosphate...

Development and Advanced Analysis of Dynamic and Static Casing Strain Monitoring to Characterize the Orientation and Dimensions of Hydraulic Fractures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruno, Michael; Ramos, Juan; Lao, Kang

Horizontal wells combined with multi-stage hydraulic fracturing have been applied to significantly increase production from low permeability formations, contributing to expanded total US production of oil and gas. Not all applications are successful, however. Field observations indicate that poorly designed or placed fracture stages in horizontal wells can result in significant well casing deformation and damage. In some instances, early fracture stages have deformed the casing enough so that it is not possible to drill out plugs in order to complete subsequent fracture stages. Improved fracture characterization techniques are required to identify potential problems early in the development of themore » field. Over the past decade, several new technologies have been presented as alternatives to characterize the fracture geometry for unconventional reservoirs. Monitoring dynamic casing strain and deformation during hydraulic fracturing represents one of these new techniques. The objective of this research is to evaluate dynamic and static strains imposed on a well casing by single and multiple stage fractures, and to use that information in combination with numerical inversion techniques to estimate fracture characteristics such as length, orientation and post treatment opening. GeoMechanics Technologies, working in cooperation with the Department of Energy, Small Business Innovation Research through DOE SBIR Grant No: DE-SC-0017746, is conducting a research project to complete an advanced analysis of dynamic and static casing strain monitoring to characterize the orientation and dimensions of hydraulic fractures. This report describes our literature review and technical approach. The following conclusions summarize our review and simulation results to date: A literature review was performed related to the fundamental theoretical and analytical developments of stress and strain imposed by hydraulic fracturing along casing completions and deformation monitoring techniques. Analytical solutions have been developed to understand the mechanisms responsible for casing deformation induced by hydraulic fracturing operations. After reviewing a range of casing deformation techniques, including fiber optic sensors, borehole ultrasonic tools and electromagnetic tools, we can state that challenges in deployment, data acquisition and interpretation must still be overcome to ensure successful application of strain measurement and inversion techniques to characterize hydraulic fractures in the field. Numerical models were developed to analyze induced strain along casing, cement and formation interfaces. The location of the monitoring sensor around the completion, mechanical properties of the cement and its condition in the annular space can impact the strain measurement. Field data from fiber optic sensors were evaluated to compare against numerical models. A reasonable match for the fracture height characterization was obtained. Discrepancies in the strain magnitude between the field data and the numerical model was observed and can be caused by temperature effects, the cement condition in the well and the perturbation at the surface during injection. To avoid damage in the fiber optic cable during the perforation (e.g. when setting up multi stage HF scenarios), oriented perforation technologies are suggested. This issue was evidenced in the analyzed field data, where it was not possible to obtain strain measurement below the top of the perforation. This presented a limitation to characterize the entire fracture geometry. The comparison results from numerical modeling and field data for fracture characterization shows that the proposed methodology should be validated with alternative field demonstration techniques using measurements in an offset observation well to monitor and measure the induced strain. We propose to expand on this research in Phase II with a further study of multi-fracture characterization and field demonstration for horizontal wells.« less

[Calcaneal fractures treated by open reduction and internal fixation with a locking compression plate (LCP). A prospective study. part I: basic analysis of the group].

PubMed

Svatoš, F; Bartoška, R; Skála-Rosenbaum, J; Douša, P; Pacovský, V; Krbec, M

2011-01-01

In a prospective study of patients with calcaneal fractures treated by open reduction from an extensile lateral approach and LCP osteosynthesis, the authors evaluated the basic epidemiological data, mechanism of injury, type of fracture, essential data on surgery, days of hospital stay and the number of complications. In the period from September 1, 2006 to July 31, 2010, a total of 230 patients with 243 calcaneal fractures were treated. The fractures were classified as either open or closed and according to the Essex-Lopresti system. Of the total number of patients, 135 (55.6 % of all fractures) were indicated for conservative treatment and 108 (44.4% of all fractures) for surgical intervention. Indications for surgery based on the generally accepted criteria enabled us to select 77 patients with 82 fractures (33.7 % of all fractures) for treatment by the method of open reduction and LCP osteosynthesis. These patients constituted the group evaluated here. The other patients were treated using other techniques (21 fractures, i.e., 8.6 % of all fractures, by the Stehlík-Štulík transfixation method and further five [2.1 %] by screw osteosynthesis). Six surgeons were involved in the treatment of this group. For the diagnosis of fractures, plain radiographs in lateral and axial projection and axial and coronal CT images were used. All fractures were treated after subsidence of oedema by the method of open reduction and LCP fixation from an extensile lateral approach, with the use of a tourniquet. The follow-up period for the evaluation of functional outcome and bone union was 3 to 48 months. Fifty patients were followed up for over one year. The group evaluated comprised 58 men (75.3 %) with 63 fractures (76.8 %) and 19 women (24.7 %) with 19 fractures (23.2 %). The average age of the group was 42 years, with 41 years (range, 22-61 years) in men and 47 years (range, 30-70 years) in women. The most frequent cause of injury was a fall from a height below 1 metre and this was recorded in 38 patients (49.4 %); 18 patients (24.3 %) had a fall from a height below 3 metres. Eight fractures were caused by a fall from the window, seven calcaneal fractures, as part of .polytrauma, were sustained in road accidents (9.1 %) and six calcaneal bones were injured due to ankle sprain in walking on a flat surface (7.8 %). Bilateral fractures occurred in five (6.5 %) patients, the right and left heel bones were injured in 31 (40.3 %) and 41 (53.2 %) fracture cases, respectively. An open fracture was recorded on three occasions (3.7 %). Of the 82 evaluated fractures, 23 were type IIa fractures (28 %) and 59 were type IIb fractures (72 %) according to the Essex-Lopresti classification system. The average injury-surgery interval was 10 days (range, 1 - 23 days). The average operative time was 77 minutes (range, 45-175 min) and the average duration of tourniquet application was 61 minutes (range, 20-130 min). The average length of hospital stay was 18 days (range, 7-61 days). In 15 patients (18.3 % of osteosynthesis cases) wound healing was delayed. Deep wound infection developed in three cases (3.7 %); these required revision surgery which involved implant removal before bone union in two cases and healing of the wound after revision without implant removal in one case. A necrotic lesion in one case (1.2 %) was treated by muscle flap transfer. Complications which varied in type and severity were recorded in 22 % of the patients. The Rowe score was used to evaluate functional outcomes, which were excellent in 44 %, good in 46 %, satisfactory in 4 % and poor in 6 % of the surgically treated patients.. Only about one-third of the patients with calcaneal fractures were indicated for open LCP osteosynthesis. This is in agreement with the strict indication criteria established by the foreign authors with Professors Zwipp and Sanders at the head. It appears that this fracture chiefly occurs in the population of young active men (Kočiš reported only men and no woman with this fracture in his study). The authors focus on exact radiographic diagnosis including CT examination, as recommended by Stehlík and Štulík in their book. They recommend to use the Essex-Lopresti system for primary classification and, because of the frequency of LCP osteosynthesis procedures performed, also recommend to carry out this treatment in specialised institutions. The rate of serious complications in this study was relatively low and in accordance with the findings of Zwipp, Zeman and others. The analysis of basic data on the group of patients with calcaneal fractures treated by open reduction and LCP fixation showed the following: chiefly young active men sustained this fracture; calcaneal fracture was usually due to a fall or jump from a level not too high; X-ray examination (lateral and axial projection) was sufficient to make a diagnosis; for a decision to operate it was useful to complete the diagnosis by CT examination; the prerequisite for minimising post-operative complications was strict adherence to the established indication criteria, surgery only after oedema had subsided and use of the correct surgical technique. The number of complications and their nature did not differ from the data reported by other authors.

Morphometric study on dimensions of various parts of pons and comparison of data in accordance with age and sex of healthy people by MRI.

PubMed

Rajaei, Farzad; Salahshoor, Mohammad-Reza; Hashemi, Hassan-Jahani; Haghdoost-Yazdi, Hahsem; Pahlevan, Ali-Asghar

2009-12-01

The emergence of magnetic Resonance Imaging (MRI) technique has made it possible to answer many questions in the field of anatomy more precisely while observing different anatomic parts of living persons at different ages. This study was conducted to determine the dimensions of different parts of pons and also comparing the data in accordance with age and sex by MRI. The present study carried out on 300 healthy individuals referred to imaging center at Imam Reza hospital in the city of Kermanshah, Iran. The precondition for people to be included in the study was the approval made by in-house physician based on person's state of health and the lack of any pathological lesion in brain on the basis of images obtained by MRI. Following MRI procedure, the dimensions of target parts in pons were calculated by the MRI-associated measuring system and recorded along with the age and sex of the patients. Measurements were recorded in mm and based on selecting the largest height, width and length of the organ during the examination of all axial, sagittal, and T(1) coronal profiles. Data analysis was performed using t-student test and Pearson's correlation. The significance level was set at P=0.05. The mean size of different parts of pons recorded in mm was as follows: The height of tegmentum of pons in men and women were 21.10+/-1.99 and 20.35+/-1.95, respectively. The height of ventricle of pons was 24.96+/-1.45 in men and 23.72+/-1.41 in women. The length of pons in men was 21.40+/-1.55 and in women 21.10+/-1.28. The length of ventricle in men and women were 16.85+/-1.21 and 16.77+/-1.36, respectively. The length of tegmentum of pons was 4.57+/-0.50 in men and 4.40+/-0.58 in women. Lastly, the transverse length of the ventricle of pons was 27.30+/-1.68 in men and 26.52+/-1.63 in women. The values obtained for the transverse length, length of tegmentum of ventricle, height of ventricle and height of tegmentum in men were larger than those found for women. There were significant relationships between the transverse length, length of tegmentum of pons, height of ventricle of pons and the age in men. There was no significant relationship between dimension of pons and age in women.

Comparison of analgesic interventions for traumatic rib fractures: a systematic review and meta-analysis.

PubMed

Peek, Jesse; Smeeing, Diederik P J; Hietbrink, Falco; Houwert, Roderick M; Marsman, Marije; de Jong, Mirjam B

2018-02-06

Many studies report on outcomes of analgesic therapy for (suspected) traumatic rib fractures. However, the literature is inconclusive and diverse regarding the management of pain and its effect on pain relief and associated complications. This systematic review and meta-analysis summarizes and compares reduction of pain for the different treatment modalities and as secondary outcome mortality during hospitalization, length of mechanical ventilation, length of hospital stay, length of intensive care unit stay (ICU) and complications such as respiratory, cardiovascular, and/or analgesia-related complications, for four different types of analgesic therapy: epidural analgesia, intravenous analgesia, paravertebral blocks and intercostal blocks. PubMed, EMBASE and CENTRAL databases were searched to identify comparative studies investigating epidural, intravenous, paravertebral and intercostal interventions for traumatic rib fractures, without restriction for study type. The search strategy included keywords and MeSH or Emtree terms relating blunt chest trauma (including rib fractures), analgesic interventions, pain management and complications. A total of 19 papers met our inclusion criteria and were finally included in this systematic review. Significant differences were found in favor of epidural analgesia for the reduction of pain. No significant differences were observed between epidural analgesia, intravenous analgesia, paravertebral blocks and intercostal blocks, for the secondary outcomes. Results of this study show that epidural analgesia provides better pain relief than the other modalities. No differences were observed for secondary endpoints like length of ICU stay, length of mechanical ventilation or pulmonary complications. However, the quality of the available evidence is low, and therefore, preclude strong recommendations.

How Does Ankle-foot Orthosis Stiffness Affect Gait in Patients With Lower Limb Salvage?

DTIC Science & Technology

2014-05-10

characteristics Group Age (years) Height Mass Months of IDEO use Diagnosis IDEO 1 28 1.92 96.4 3.9 R LE neuropathy 2 21 1.79 95.7 11.3 R paresis 3 30...1.78 97.3 7.5 R LE tissue loss/trauma 4 40 1.81 81.0 9.3 L ankle fracture and osteoarthritis 5 30 1.75 79.1 9.8 L tibia/fibula fracture 6 30 1.76 78.2...11.0 L LE neuropathy, crushed tibia/fibula 7 36 1.78 75.5 4.4 L LE talar fracture, multiple fractures 8 22 1.64 80.3 9.0 R LE tissue loss/trauma 9 27

Formation and evolution of radial fracture systems on Venus

NASA Technical Reports Server (NTRS)

Parfitt, E. A.; Head, James W.

1993-01-01

A survey of approximately 90 percent of the surface of Venus using Magellan data has been carried out to locate all radial fracture systems and to assess their association with other features such as volcanic edifices and coronae. Squyres et al. and Stofan et al. have discussed the association of radial fracture features in relation to coronae features, our approach was to assess the associations of all of the fracture systems. These fracture systems have two broad types of form - some fracture systems are associated with updomed topography, radiate from a point and have relatively uniform fracture lengths while others have a wider range of fracture lengths and radiate from the outer edge of a central caldera. Squyres et al. and Stofan et al. have interpreted both types of feature as reflecting tectonic fracturing resulting from uplift of the surface as a mantle plume impinges upon the crust. While it is true that a number of features are related to uplift and that such uplift will induce stresses consistent with radial fracturing, we explore the possibility that these fractures are not exclusively of tectonic origin. Purely tectonic fracturing will tend to generate a few main fractures/faults along which most of the stresses due to uplift will be accommodated leading to the triple-junction form common for terrestrial updoming. Though this type of feature is observed on Venus (e.g., feature located at 34S86), the majority of radial fracture systems display much more intensive fracturing than this through a full 360 degrees; this is difficult to explain by purely tectonic processes. The association of many of the fractures with radial lava flows leads us to interpret these fractures as reflecting dike emplacement: the form of the fractures being consistent with primarily vertical propagation from the head of a mantle plume. In the case of the second type of fracture system (those radiating from a central caldera), an even stronger case can be made that the fractures are not of tectonic origin. These features are not as commonly associated with updoming of the surface and where they are, the fractures extend out well beyond the edge of the topographic rise - an observation which is not consistent with the fractures being of tectonic uplift origin. Furthermore the fractures have a distribution of lengths (many short, fewer long) which is characteristic of dike swarms, and show direct associations with calderas and lava flows consistent with a volcanic origin. In addition, the longest fractures have a radial pattern only close to the center of the system but bend with distance to align themselves with the regional stress field - this behavior is very difficult to explain on purely tectonic grounds but is a pattern commonly seen for terrestrial dikes. For these reasons, we argue that many, if not the majority, of radial fracture systems found on Venus are the surface reflection of dike swarms, those associated with positive topography reflecting vertical emplacement and those radiating from calderas reflecting lateral propagation.

Taiwanese adult foot shape classification using 3D scanning data.

PubMed

Lee, Yu-Chi; Wang, Mao-Jiun

2015-01-01

This study classifies the foot shapes of Taiwanese using 3D foot scanning data from 2000 males and 1000 females. Nine foot dimensions relative to foot length and absolute measures in the common foot length categories were applied to compare the gender differences. Using foot breadth in % foot length (% FL), ball of foot length in % FL and arch height in % FL as feature parameters, three foot shape types for males and females can be classified. Significant gender differences were found in seven of the nine foot dimensions. Females had greater ball of foot length than males (0.2% FL). When comparing feet of the same foot length, males had greater breadth, girth and height dimensions than females, except for toe height. In addition, ethnic differences in foot shape were also observed. The findings can provide very useful information for building gender-specific shoe lasts and designing footwear insoles. 3D foot scanning data of 2000 males and 1000 females were classified into three different footshapes for males and females, respectively. Gender and ethnic differences on foot shape were also compared. The finding scan provide very useful information for gender-specific shoe last design and footwear production.

Social support and actual versus expected length of stay in inpatient rehabilitation facilities

PubMed Central

Lewis, Zakkoyya H.; Hay, Catherine Cooper; Graham, James E.; Lin, Yu-Li; Karmarkar, Amol M.; Ottenbacher, Kenneth J.

2016-01-01

Objectives Describe impairment-specific patterns in shorter- and longer-than-expected lengths of stay in inpatient rehabilitation and examine the independent effects of social support on deviations from expected lengths of stay. Design Retrospective cohort study. Setting Inpatient rehabilitation facilities across the United States. Participants Medicare fee-for-service beneficiaries (N=119,437) who were discharged from inpatient rehabilitation facilities in 2012 following stroke, lower extremity fracture, or lower extremity joint replacement. Intervention Not applicable. Main Outcome Measure Relative length of stay (actual – expected). The Centers for Medicare and Medicaid Services posts annual expected lengths of stay based on patients’ clinical profiles at admission. We created a 3-category outcome variable: short, expected, long. Our primary independent variable (social support) also included 3 categories: family/friends, paid/other, none. Results Mean (SD) actual lengths of stay for joint replacement, fracture, and stroke were 9.8 (3.6), 13.8 (4.5), and 15.8 (7.3) days, respectively; relative lengths of stay were −1.2 (3.1), −1.6 (3.7), and −1.7 (5.2) days. Nearly half of patients (47–48%) were discharged more than 1 day earlier than expected in all 3 groups, whereas 14% of joint replacement, 15% of fracture, and 20% of stroke patients were discharged more than 1 day later than expected. In multinomial regression analysis, using family/friends as the reference group, paid/other support was associated (p<.05) with higher odds of long stays in joint replacement. No social support was associated with lower odds of short stays in all 3 impairment groups and higher odds of long stays in fracture and joint replacement. Conclusion Inpatient rehabilitation experiences and outcomes can be substantially impacted by a patient’s level of social support. More research is needed to better understand these relationships and possible unintended consequences in terms of patient access issues and provider-level quality measures. PMID:27373747

Fragility fractures at Auckland City Hospital: we can do better.

PubMed

Braatvedt, Geoffrey; Wilkinson, Susan; Scott, Marilyn; Mitchell, Paul; Harris, Roger

2017-12-01

This study describes in detail the burden of caring for patients aged ≥ 50 years seen in one year with a fragility fracture in a large urban environment and shows that these fractures result in a long length of stay and significant mortality. Intervention to prevent further fracture was poorly done. To examine the epidemiology of fragility fracture in patients over age 50 years and record the number who received appropriate secondary prevention treatment. All patients aged ≥ 50 years presenting with a fracture during the 12 months following July 1 st 2011, to Auckland City Hospital or residing in central Auckland at the time of their fracture, were identified from hospital and Accident Compensation Corporation records. A random sample of 55% of these patient's records were reviewed to establish the type of fracture, prior fracture and falls history, and use of bisphosphonates in the 12 months before presentation. Their length of stay (LOS) by type of fracture was recorded. The use of bisphosphonate drugs in the following 12 months was obtained from centralised national records of prescriptions. 2729 patients aged ≥ 50 years presented with a fragility fracture in the central Auckland region in one year. Fifty-six percent of these patients were seen at Auckland Hospital and of these, 82% patients required admission with a mean LOS of 20 days (SD ± 24 days).The remaining 44% of patients were looked after in the private outpatient sector. Approximately 30% of the admissions were for hip fracture. Sixty-four percent of patients with a fragility fracture did not receive a potent bisphosphonate, 12% were considered not appropriate for treatment, and 24% received a potent bisphosphonate during their admission or in the next 12 months. Approximately 1 in 18 people aged ≥ 50 years presented in one year with a fragility fracture.Secondary prevention strategies were poorly implemented. Additional resources for identifying and initiating secondary fracture prevention care such as a Fracture Liaison Service are urgently needed.

The Association between Sagittal Index, Canal Compromise, Loss of Vertebral Body Height, and Severity of Spinal Cord Injury in Thoracolumbar Burst Fractures

PubMed Central

Yüksel, Mehmet Onur; Gürbüz, Mehmet Sabri; Gök, Şevki; Karaarslan, Numan; İş, Merih; Berkman, Mehmet Zafer

2016-01-01

Aim: Our aim was to determine whether a combination of sagittal index (SI), canal compromise (CC), and loss of vertebral body height (LVBH) is associated with the severity of neurological injury in patients with thoracolumbar burst fractures. Materials and Methods: Seventy-four patients with thoracolumbar burst fracture undergoing instrumentation between 2010 and 2015 were analyzed retrospectively. The degree of neurological injury was determined using the American Spinal Injury Association (ASIA) scoring system. The association between the morphology of the fracture and the severity of neurological injury was analyzed. Results: There was a strong association between fracture morphology and the severity of neurological injury. Of the patients, 77.5% with SI ≥20°, 81.6% with CC ≥40%, and 100% with LVBH ≥50% had lesion according to ASIA. All of 7 patients with ASIA A had SI ≥20°, CC ≥40%, and LVBH ≥50%. On the other hand, 79% of the patients with ASIA E had SI <20°, 83.7% of the patients with ASIA E had CC <40%, and all of the patients with ASIA E had LVBH <50%. SI, CC, and LVBH were lower in neurologically intact patients (ASIA E), whereas they were higher in patients with neurological deficits (ASIA A, B, C, D) (P = 0.001; P < 0.01). These measurements had 100% negative predictive values and relatively high positive predictive values. Conclusion: SI, CC, and LVBH are significantly associated with the severity of neurological injury in patients with thoracolumbar burst fractures. The patients with SI >25°, the patients with CC >40%, and the patients with LVBH >50% are likely to have a more severe neurological injury. PMID:28163505

Performance of Chevron-notch short bar specimen in determining the fracture toughness of silicon nitride and aluminum oxide

NASA Technical Reports Server (NTRS)

Munz, D.; Bubsey, R. T.; Shannon, J. L., Jr.

1980-01-01

Ease of preparation and testing are advantages unique to the chevron-notch specimen used for the determination of the plane strain fracture toughness of extremely brittle materials. During testing, a crack develops at the notch tip and extends stably as the load is increased. For a given specimen and notch configuration, maximum load always occurs at the same relative crack length independent of the material. Fracture toughness is determined from the maximum load with no need for crack length measurement. Chevron notch acuity is relatively unimportant since a crack is produced during specimen loading. In this paper, the authors use their previously determined stress intensity factor relationship for the chevron-notch short bar specimen to examine the performance of that specimen in determining the plane strain fracture toughness of silicon nitride and aluminum oxide.

The effects of confining pressure and stress difference on static fatigue of granite

NASA Technical Reports Server (NTRS)

Kranz, R. L.

1979-01-01

Samples of Barre granite were creep tested at room temperature at confining pressures up to 2 kilobars. The time to fracture increased with decreasing stress difference at every pressure, but the rate of change of fracture time with respect to the stress difference increased with pressure. At 87% of the short-term fracture strength, the time to fracture increased from about 4 minutes at atmospheric pressure to longer than one day at 2 Kb of pressure. The inelastic volumetric strain at the onset of tertiary creep, delta, was constant within 25% at any particular pressure but increased with pressure in a manner analogous to the increase of strength with pressure. At the onset of tertiary creep, the number of cracks and their average length increased with pressure. The crack angle and crack length spectra were quite similar, however, at each pressure at the onset of tertiary creep.

Impact of Microorganisms on Unsatured Flow within Fractures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daphne L. Stoner; Robert D. Stedtfeld; Tina L. Tyler

An experiment is described in which a groundwater bacterium, Sphingomonas sp., influenced the dynamics of unsaturated flow at a fracture intersection. A washed cell suspension increased by three-fold the length of time that water pooled at the fracture intersection. On the other hand, the addition of growth substrates resulted in cell growth and the conversion from intermittent to continuous flow behavior at the fracture intersection. The results suggest that microbial properties and processes need to be included with other important variables for understanding unsaturated flow in fractured geomatrices.

Pulse fracture simulation in shale rock reservoirs: DEM and FEM-DEM approaches

NASA Astrophysics Data System (ADS)

González, José Manuel; Zárate, Francisco; Oñate, Eugenio

2018-07-01

In this paper we analyze the capabilities of two numerical techniques based on DEM and FEM-DEM approaches for the simulation of fracture in shale rock caused by a pulse of pressure. We have studied the evolution of fracture in several fracture scenarios related to the initial stress state in the soil or the pressure pulse peak. Fracture length and type of failure have been taken as reference for validating the models. The results obtained show a good approximation to FEM results from the literature.

Scratching as a Fracture Process: From Butter to Steel

NASA Astrophysics Data System (ADS)

Akono, A.-T.; Reis, P. M.; Ulm, F.-J.

2011-05-01

We present results of a hybrid experimental and theoretical investigation of the fracture scaling in scratch tests and show that scratching is a fracture dominated process. Validated for paraffin wax, cement paste, Jurassic limestone and steel, we derive a model that provides a quantitative means to relate quantities measured in scratch tests to fracture properties of materials at multiple scales. The scalability of scratching for different probes and depths opens new venues towards miniaturization of our technique, to extract fracture properties of materials at even smaller length scales.

EFFECTS OF MINERAL CONTENT ON THE FRACTURE PROPERTIES OF EQUINE CORTICAL BONE IN DOUBLE-NOTCHED BEAMS

PubMed Central

McCormack, Jordan; Stover, Susan M.; Gibeling, Jeffery C.; Fyhrie, David P.

2012-01-01

We recently developed a method to measure cortical bone fracture initiation toughness using a double-notched beam in four-point bending. This method was used to test the hypothesis that mineralization around the two notch roots is correlated with fracture toughness and crack extension (physical damage). Total energy absorbed to failure negatively correlated with average mineralization of the beam (r2=0.62), but not with notch root mineralization. Fracture initiation toughness was positively correlated to mineralization at the broken notch root (r2=0.34). Crack length extension at the unbroken notch was strongly negatively correlated with the average mineralization of the notch roots (r2=0.81) whereas crack length extension at the broken notch did not correlate with any of the mineralization measurements. Mineralization at the notch roots and the average mineralization contributed independently to the mechanical and damage properties. The data are consistent with an hypothesis that a) high notch root mineralization results in less stable crack length extension but high force to initiate unstable crack propagation while b) higher average mineralization leads to low post-yield (and total) energy absorption to failure. PMID:22394589

Contraction fracture: From 90° to 120° crack intersections

NASA Astrophysics Data System (ADS)

Lazarus, V.; Gauthier, G.; Pauchard, L.

2009-12-01

Giant's Causeway, Port Arthur tessellated pavement, Bimini Road, Mars polygons (whose presence indicated past occurrence of water), fracture networks in permafrost, septarias are some more or less known examples of self-organized crack patterns that have intrigued people through out history. Even now, they are sometimes attributed to legendary figures : Giant's, Atlantis mythical citizens. These pavements are in fact formed by constrained shrinking of the media due, for instance, to cooling or drying leading to fracture. The crack networks form mostly 90° or 120° angles. Here, we report experiments allowing to control the transition between 90° and 120°. We show that the transition is governed by the linear elastic fracture mechanics energy minimization principle, hence by two parameters: the cell size and the Griffith's length (minimum crack length beyond which the bulk energy is not sufficient to allow its propagation). This was achieved by measuring the Griffith's length directly on the same type of experiments by changing the cell geometry. Example of 90 degree and 120 crack intersections. Top-left : Giant's Causeway hexagonal tessellated pavement, Ireland (courtesy A. Davaille). Top-right: Port Arthur rectangular tessellated pavement, Tasmania (courtesy Wayne Bentley). Bottom : septarias (courtesy A. Rifki and M. Toussaint)

Boulder coastal deposits at Favignana Island rocky coast (Sicily, Italy): Litho-structural and hydrodynamic control

NASA Astrophysics Data System (ADS)

Pepe, Fabrizio; Corradino, Marta; Parrino, Nicolò; Besio, Giovanni; Presti, Valeria Lo; Renda, Pietro; Calcagnile, Lucio; Quarta, Gianluca; Sulli, Attilio; Antonioli, Fabrizio

2018-02-01

Boulders are frequently dislodged from rock platforms, transported and deposited along coastal zones by high-magnitude storm waves or tsunamis. Their size and shape are often controlled by the thickness of bedding planes as well as by high-angle to bedding fracture network. We investigate these processes along two coastal areas of Favignana Island by integrating geological data for 81 boulders, 49 rupture surfaces (called sockets) and fracture orientation and spacing with four radiocarbon dates, numerical hydrodynamic analysis, and hindcast numerical simulation data. Boulders are scattered along the carbonate platform as isolated blocks or in small groups, which form, as a whole, a discontinuous berm. Underwater surveys also highlight free boulders with sharp edges and sockets carved out in the rock platform. Boulders are composed of ruditic- to arenitic-size clastic carbonates. Their size ranges from 0.6 to 3.7 m, 0.55 to 2.4 m, and 0.2 to 1 m on the major (A), medium (B), and minor (C) axes, respectively. The highest value of mass estimation is 12.5 t. Almost all of boulders and sockets are characterized by a tabular or bladed shape. The comparisons between a) the fractures spacing and the length of A- and B-axes, and b) the frequency peaks of C-axis with the recurrent thickness of beds measured along the coastal zone demonstrate the litho-structural control in the size and shape of joint-bounded boulders. These comparisons, together with the similarity between the shapes of the boulders and those of the sockets as well as between the lithology of boulders and the areas surrounding the sockets, suggest that blocks originate by detachment from the platform edge. Thus, the most common pre-transport setting is the joint-bounded scenario. Hydrodynamic equations estimate that the storm wave heights necessary to initiate the transport of blocks diverge from 2 m to 8 m for joint-bounded boulders and from few tens of centimeters up to 11 m for submerged boulders. The comparison between the wave heights at the breaking point of the coastal zones with the results of hydrodynamic equations shows that waves approaching the coastline are able to transport all surveyed boulders. Our data suggest that boulders have been transported by several storm events, even in very recent times.

Generational changes in the growth of children from Maribor and Slovenia.

PubMed

Bigec, Martin

2013-05-01

Among the numerous factors which influence a child's growth and development are also factors of changeable socio-economic environment and life style. Our aim was to evaluate these changes and contribute to preventive measures and evaluation of a child's growth in pediatric practice. Therefore, we decided to estimate the state of body growth in two generations of children from Maribor at five and six years of age of both gender, establish secular changes and define standards. On a representative sample (gender and age) of 1461 children from Maribor measured in 1996 and a sample of 608 children from Maribor, measured in 1966, 28 body features were studied and compared in each population unit. Variables were statistically and epidemiologically assessed and results were controlled by a test. The following anthropometric differences were significant: in 5-year old boys the measures in the 1996 generation are statistically higher than in 1966 - foot length, head length, upper arm skinfold, subscapular skinfold, arm length, arm diameter, upper thigh skinfold, stature (length), suprailiac skinfold, and body weight. Decreased measures are: abdomen circumference, knee circumference, sitting height, elbow circumference, biacromial diameter, and face heigth. In 6-year old boys additional features have increased in comparison with the year 1966: sternal height, tight circumference, hip width, chest circumference; following measures have decreased: face height, head circumference. In 5-year old girls: increased measures in comparison with the generation from 1966 are: lower leg length, head length, ankle circumference, upper arm skinfold, body weight, billiac diameter, body height, subscapular skinfold, chest circumference, hip circumference, sternal height, suprailiac skinfold, decreased measures are: head circumference, elbow circumference, face circumference, shoulder with, sitting height. In 6-year old girls additional measures are increased: wrist circumference, arm length and chest circumference. Changing trends show an increased tendency towards decrease or increase of most body measurements. In everyday practice the most commonly used measurements are: body mass, head circumference, body length in babies and body height in pre-school children. Our measurements proved, with a p-value of 0.001, that measurements of children in 1966, also shown in diagrams, are significantly different from measurements in 1996. In the second part of this paper we present a part of the anthropometric measurement study carried out for the standardization of the DENVER II developmental screening test. There were 1596 healthy Slovene children between zero and six and half years of age included into the observation. Children come from Maribor, Koper, Velenje and Ljubljana. We used the Cameron's measurement and statistical method. Diagrams were made for following body measures: body mass, body height, head circumference, upper arm circumference, thigh circumference and body mass index. A comparative analysis with the Euro-Growth study showed that our results correspond with the European standards. Therefore, our results are suggested to be applied in everyday pediatric practice.

Miniplate for osteosynthesis in a 9-year-old with symphysis fracture: clinical report.

PubMed

Srinivasan, Ila; Kumar, Naveen; Jaganathan, Udhya; Bhandari, Arihant

2013-09-01

Osteosynthesis using minimum material in pediatric mandibular fractures is the key, due to the limited space available in the mandible, especially in the mental foramen and apical region. There is an important role of open reduction and rigid internal fixation in re-establishing facial height, width and projection. During the early years of growth and development, there is a high osteogenic potential of the bones. The thick periosteum allows for rapid consolidation and remodeling at the site of fracture. Primary teeth have short, bulbous crowns which compromise stable maxillomandibular fixation during fracture reduction and stabilization using traditional methods. Further, stability of the fractured segments may be hampered because of the displaced or mobile permanent anterior teeth in the mixed dentition along the line of fracture. This clinical report outlines the use of miniplate with monocortical screws in a 9-year-old boy with symphysis fracture. How to cite this article: Srinivasan I, Kumar N, Jaganathan U, Bhandari A. Miniplate for Osteosynthesis in a 9-Year-Old with Symphysis Fracture: Clinical Report. Int J Clin Pediatr Dent 2013;6(3):213-216.

Callus features of regenerate fracture cases in femoral lengthening in achondroplasia.

PubMed

Devmurari, Kamlesh N; Song, Hae Ryong; Modi, Hitesh N; Venkatesh, K P; Ju, Kim Seung; Song, Sang Heon

2010-09-01

We studied the callus features seen in cases of regenerate fracture in femoral lengthening using a monolateral fixator in achondroplasia to determine whether callus types and shapes can predict the probability of callus fracture. The radiographs of 28 cases of femoral lengthening in 14 patients, 14 cases of callus fracture, and 14 cases without callus fracture were retrospectively analyzed by four observers and classified into different shapes and types in concordance with the Ru Li classification. The average lengthening of 9.4 cm (range 7.5-11.8 cm) was achieved, which was 41% (range 30-55%) of the original length and the average timing of callus fracture was 470 days (range 440-545 days) after surgery in the callus fracture group. While the average lengthening of 9.1 cm (range 8-9.7 cm) was achieved, this was 30% (range 28-32%) of the original length in the group of patients without callus fracture. The callus was atypically shaped, there was a 48% average (range 30-72%) reduction of the callus width compared with the natural width of the femur, and a lucent pathway was present in all cases of regenerate fracture. A lucent pathway was seen in all fracture cases with concave, lateral, and atypical shapes, and there was more than 30% lengthening and 30% reduction of the callus width compared with the natural width of the femur, which are the warning signs for regenerate fractures. These signs help the surgeon to predict the outcome and guide him in planning for any additional interventions. The Ru Li classification is an effective method for the evaluation of the chance of callus fracture.

Reference values of anthropometric measurements in Dutch children. The Oosterwolde Study.

PubMed

Gerver, W J; Drayer, N M; Schaafsma, W

1989-03-01

In the period 1979-1980 the following anthropometric measurements were recorded in 2351 healthy Dutch children from 0-17 years of age: height, weight, sitting height, arm span, lengths of upper-arm, lower-arm and hand, tibial length, foot length, biacromial diameter, biiliacal diameter, and head circumference. Corresponding percentile values were constructed on the basis of normality assumptions, the mean and standard deviation at age t being determined by a cubic spline approximation. The results are compared with other studies and given in the form of growth charts.

Short uncemented stems allow greater femoral flexibility and may reduce peri-prosthetic fracture risk: a dry bone and cadaveric study.

PubMed

Jones, Christopher; Aqil, Adeel; Clarke, Susannah; Cobb, Justin P

2015-09-01

Short femoral stems for uncemented total hip arthroplasty have been introduced as a safe alternative to traditional longer stem designs. However, there has been little biomechanical examination of the effects of stem length on complications of surgery. This study aims to examine the effect of femoral stem length on torsional resistance to peri-prosthetic fracture. We tested 16 synthetic and two paired cadaveric femora. Specimens were implanted and then rapidly rotated until fracture to simulate internal rotation on a planted foot, as might occur during stumbling. 3D planning software and custom-printed 3D cutting guides were used to enhance the accuracy and consistency of our stem insertion technique. Synthetic femora implanted with short stems fractured at a significantly higher torque (27.1 vs. 24.2 Nm, p = 0.03) and angle (30.3° vs. 22.3°, p = 0.002) than those implanted with long stems. Fracture patterns of the two groups were different, but showed remarkable consistency within each group. These characteristic fracture patterns were closely replicated in the pair of cadaveric femora. This new short-stemmed press-fit femoral component allows more femoral flexibility and confers a higher resistance to peri-prosthetic fracture from torsional forces than long stems.

Modeling of fault reactivation and induced seismicity during hydraulic fracturing of shale-gas reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rutqvist, Jonny; Rinaldi, Antonio P.; Cappa, Frédéric

2013-07-01

We have conducted numerical simulation studies to assess the potential for injection-induced fault reactivation and notable seismic events associated with shale-gas hydraulic fracturing operations. The modeling is generally tuned towards conditions usually encountered in the Marcellus shale play in the Northeastern US at an approximate depth of 1500 m (~;;4,500 feet). Our modeling simulations indicate that when faults are present, micro-seismic events are possible, the magnitude of which is somewhat larger than the one associated with micro-seismic events originating from regular hydraulic fracturing because of the larger surface area that is available for rupture. The results of our simulations indicatedmore » fault rupture lengths of about 10 to 20 m, which, in rare cases can extend to over 100 m, depending on the fault permeability, the in situ stress field, and the fault strength properties. In addition to a single event rupture length of 10 to 20 m, repeated events and aseismic slip amounted to a total rupture length of 50 m, along with a shear offset displacement of less than 0.01 m. This indicates that the possibility of hydraulically induced fractures at great depth (thousands of meters) causing activation of faults and creation of a new flow path that can reach shallow groundwater resources (or even the surface) is remote. The expected low permeability of faults in producible shale is clearly a limiting factor for the possible rupture length and seismic magnitude. In fact, for a fault that is initially nearly-impermeable, the only possibility of larger fault slip event would be opening by hydraulic fracturing; this would allow pressure to penetrate the matrix along the fault and to reduce the frictional strength over a sufficiently large fault surface patch. However, our simulation results show that if the fault is initially impermeable, hydraulic fracturing along the fault results in numerous small micro-seismic events along with the propagation, effectively preventing larger events from occurring. Nevertheless, care should be taken with continuous monitoring of induced seismicity during the entire injection process to detect any runaway fracturing along faults.« less

[Measurement of screw length through drilling technique in osteosynthesis of the proximal humerus fractures].

PubMed

Avcı, Cem Coşkun; Gülabi, Deniz; Sağlam, Necdet; Kurtulmuş, Tuhan; Saka, Gürsel

2013-01-01

This study aims to investigate the efficacy of screw length measurement through drilling technique on the reduction of intraarticular screw penetration and fluoroscopy time in osteosynthesis of proximal humerus fractures. Between January 2008 and June 2012, 98 patients (34 males, 64 females; mean age 64.4 years; range 35 to 81 years) who underwent osteosynthesis using locking anatomical proximal humerus plates (PHILOS) in our clinic with the diagnosis of Neer type 2, 3 or 4 were included. Two different surgical techniques were used to measure proximal screw length in the plate and patients were divided into two groups based on the technique used. In group 1, screw length was determined by a 3 mm blunt tipped Kirschner wire without fluoroscopic control. In group 2, bilateral fluoroscopic images for each screw at least were obtained. Intraarticular screw penetration was detected in five patients (10.6%) in group 1, and in 19 patients (37.3%) in group 2. The mean fluoroscopic imaging time was 10.6 seconds in group 1 and 24.8 seconds in group 2, indicating a statistically significant difference. Screw length measurement through the drilling technique significantly reduces the intraarticular screw penetration and fluoroscopy time in osteosynthesis of proximal humerus fractures using PHILOS plates.

Lifestyle and biologic contributors to proximal femur bone mineral density and hip axis length in two distinct ethnic groups of premenopausal women.

PubMed

Alekel, D L; Mortillaro, E; Hussain, E A; West, B; Ahmed, N; Peterson, C T; Werner, R K; Arjmandi, B H; Kukreja, S C

1999-01-01

Although relatively little is known about osteoporotic risk factors in women from the Indian subcontinent, osteoporotic fractures usually occur 10-20 years earlier in Indian men and women compared with their western Caucasian counterparts. The primary purpose of this cross-sectional study was to determine the relative contributions of ethnicity, reproductive history, body size (height, weight) and composition, bone turnover, serum 25(OH)vitamin D(3) [25(OH)D(3)], dietary intake (of calcium, fiber and alcohol) and energy expenditure to femoral bone mineral density (BMD) in Indian and Pakistani (Indian/Pakistani; n = 47) versus American (n = 47) Caucasians. We also contrasted femoral BMD and hip axis length in these two distinct groups of premenopausal females living in the USA. The Indian/Pakistani (0.875 +/- 0.096) women had lower (p = 0.0014) femoral BMD (g/cm(2)) than their American (0.937 +/- 0.088) counterparts, placing them at greater osteoporotic risk. However, the shorter (p = 0.0002) hip axis length (cm) of the Indian/Pakistani (10.54 +/- 0.57) versus American (11.11 +/- 0.78) Caucasians might attenuate hip fracture risk in the former group. Significant contributors to proximal femur BMD were maximum non-pregnant lifetime weight, age at menarche, ratio of summation sigma central-to-peripheral skinfold thicknesses, calcium intake from milk and usual alcohol intake. Although serum 25(OH)D(3) and urinary N-telopeptide concentrations did not contribute to femoral BMD in the regression models, the lower (p<0.0001) serum 25(OH)D(3) (33.1 +/- 16.5 vs 64.0 +/- 22.0 nmol/l) and higher (p = 0.0004) urinary N-telopeptide (45.9 +/- 43.3 vs 18.9 +/- 18.7 nmol BCE/mmol) values in Indian/Pakistani versus American Caucasians, respectively, coupled with their lower BMD, places the Indian/Pakistani women at greater osteoporotic risk. These results suggest that a clinical trial to increase BMD and reduce osteoporotic risk is warranted in this ethnic group of premenopausal women.

EGS in sedimentary basins: sensitivity of early-flowback tracer signals to induced-fracture parameters

NASA Astrophysics Data System (ADS)

Karmakar, Shyamal; Ghergut, Julia; Sauter, Martin

2015-04-01

Artificial-fracture design, and fracture characterization during or following stimulation treatment is a central aspect of many EGS ('enhanced' or 'engineered' geothermal system) projects. During the creation or stimulation of an EGS, the injection of fluids, followed by flowback and production stages offers the opportunity for conducting various tracer tests in a single-well (SW) configuration, and given the typical operational and time limitations associated with such tests, along with the need to assess treatment success in real time, investigators mostly favour using short-time tracer-test data, rather than awaiting long-term 'tailings' of tracer signals. Late-time tracer signals from SW injection-flowback and production tests have mainly been used for the purpose of multiple-fracture inflow profiling in multi-layer reservoirs [1]. However, the potential of using SW short-term tracer signals for fracture characterization [2, 3] remained little explored as yet. Dealing with short-term flowback signals, we face a certain degree of parameter interplay, leading to ambiguity in fracture parameter inversion from the measured signal of a single tracer. This ambiguity can, to a certain extent, be overcome by - combining different sources of information (lithostratigraphy, and hydraulic monitoring) in order to constrain the variation range of hydrogeologic parameters (matrix and fracture permeability and porosity, fracture size), - using different types of tracers, such as conservative tracer pairs with contrasting diffusivity, or tracers pairs with contrasting sorptivity onto target surfaces. Fracture height is likely to be constrained by lithostratigraphy, while fracture length is supposed to be determinable from hydraulic monitoring (pressure recordings); the flowback rate can be assumed as a known (measurable) quantity during individual-fracture flowback. This leaves us with one or two unknown parameters to be determined from tracer signals: - the transport-effective aperture, in a water fracture (WF), or - fracture thickness and porosity, for a gel-proppant fracture (GPF). We find that parameter determination from SW early signals can significantly be improved by concomitantly using a number of solute tracers with different transport and retardation behaviour. We considered tracers of different sorptivity to proppant coatings, and to matrix rock surfaces, for GPF, as well as contrasting-diffusivity or -sorptivity tracers, for WF. An advantage of this SW approach is that it requires only small chaser volumes (few times the fracture volume), not relying on advective penetration into the rock matrix. Thus, selected tracer species are to be injected during the very last stage of the fracturing process, when fracture sizes and thus target parameters are supposed to attain more or less stable values. We illustrate the application of these tracer test design principles using hydro- and lithostratigraphy data from the Geothermal Research Platform at Groß Schönebeck [4], targeting a multi-layer reservoir (sedimentary and crystalline formations in 4-5 km depth) in the NE-German Sedimentary Basin. Acknowledgments: This work benefited from long-term support from Baker Hughes (Celle) and from the Lower-Saxonian Science and Culture Ministry (MWK Niedersachsen) within the applied research project gebo (Geothermal Energy and High-Performance Drilling, 2009-2014). The first author gratefully acknowledges continued financial support from the DAAD (German Academic Exchange Service) to pursuing Ph. D. work. References: [1] http://www.sciencedirect.com/science/article/pii/S1876610214017391 [2] http://www.geothermal-energy.org/cpdb/record_detail.php?id=7215 [3] http://www.geothermal-energy.org/cpdb/record_detail.php?id=19034 [4] http://www.gfz-potsdam.de/en/scientific-services/laboratories/gross-schoenebeck/

Parental heights and maternal education as predictors of length/height of children at birth, age 3 and 19 years, independently on diet: the ELSPAC study.

PubMed

Bienertová-Vašků, J; Zlámal, F; Pruša, T; Novák, J; Mikeš, O; Čupr, P; Pohořalá, A; Švancara, Jan; Andrýsková, L; Pikhart, H

2017-10-01

Little is currently known about the relationship between the parental diet during pregnancy and the growth of the child from early childhood until early adulthood. This study was designed to examine whether the dietary patterns of the parents during a pregnancy and of the respective child at 3 years are associated with the length/height-for-age z-score of child at birth, 3 years of age and at 19 years of age. Dietary patterns of pregnant women and their partners, and offspring at 3 years that were enroled in the 1990-1991 period in the Czech part of the European Longitudinal Study of Pregnancy and Childhood. Multivariable linear regression models were used to estimate the relationship between the dietary patterns of parents (835 child-mother-father trios) during pregnancy and the length/height-for-age z-score of their offspring at birth, 3 years and 19 years. The maternal health-conscious food pattern was found to predict lower child height at 3 years, but not at birth nor at 19 years of age. An increase in the health-conscious pattern score of the maternal diet was associated with significantly lower height-for-age z-score at 3 years; however, the observed effect lost its significance after the adjustment for diet of the child at 3 years. After full adjustment, the only significant predictors of the height-for-age z-score of the child at 3 years were the heights of both parents and maternal education. More research into the association of maternal diet in pregnancy and height of child is necessary.

Cyclic fatigue resistance of R-Pilot, WaveOne Gold Glider, and ProGlider glide path instruments.

PubMed

Keskin, Cangül; İnan, Uğur; Demiral, Murat; Keleş, Ali

2018-02-17

The aim of the present study was to compare the cyclic fatigue resistance of R-Pilot (VDW; Munich, Germany) with ProGlider (Denstply Sirona; Ballaigues, Switzerland) and WaveOne Gold Glider (Denstply Sirona; Ballaigues, Switzerland) glide path instruments. R-Pilot, ProGlider, and WaveOne Gold Glider instruments were collected (n = 15) and tested in a dynamic cyclic fatigue test device, which has an artificial canal with 60° angle of curvature and a 5-mm radius of curvature. All instruments were operated until fracture occurred, and both time to fracture (TF) and the lengths of the fractured fragments were recorded. Mean and standard deviations of TF and fragment length were calculated for each reciprocating system. TF data and fractured fragment length data were subjected to one-way ANOVA and post-hoc Tukey tests (P < 0.05). Also a Weibull analysis was performed on TF data. The cyclic fatigue resistance values of the WaveOne Gold Glider and R-Pilot were significantly higher than those of the ProGlider (P < 0.05), with no significant difference between them (P > 0.05). Weibull analysis revealed that WaveOne Gold Glider showed the highest predicted TF value for 99% survival rate, which was followed by R-Pilot and ProGlider. Regarding the length of the fractured tips, there were no significant differences among the instruments (P > 0.05). The reciprocating WaveOne Gold Glider and R-Pilot instruments had significantly higher cyclic fatigue resistance than rotary ProGlider instruments. This study reported that novel reciprocating glide path instruments exhibited higher cyclic fatigue resistance than rotating glide path instrument.

The hospital resource utilization associated with osteoporotic hip fractures in Kermanshah, Iran.

PubMed

Saeb, Morteza; Beyranvand, Mandana; Basiri, Zahra; Haghparast-Bidgoli, Hassan

2014-01-01

Hip fracture is the most serious complication of osteoporosis and imposes a significant financial burden on countries' economy. This study aimed to assess the hospitalization costs and length of stay associated with osteoporosis hip fractures and identify the major cost components in a referral hospital in Kermanshah city, Iran. In a prospective study, from May 21 2007 to May 21 2008, all patients with osteoporotic hip fracture admitted to a referral hospital for operation were recruited as the study sample. For each patient, information such as age, gender, length of stay (LOS) in hospital and intensive care unit (ICU), medical and diagnostic procedures and cost of surgery and implant were collected both through interview with the patient or a family member and the patients' hospital records. A total of 103 patients (56 men and 47 women) were studied. The average hospital length of stay (LOS) for the patients was 9.7 days, ranging from 5 to 38 days. The average total hospitalization costs was 7,208,588 IRR (US$774). The main components of the costs were ward stay (16.3%), operative (54.6%), implant (26%) and medical and diagnostic procedures (3.1%). The results of this study demonstrate that the hospital resource burden associated with osteoporotic hip fractures in Iran is substantial and expected to rise with the projected increase of life expectancy and the number of elderly in Iran. Estimating the economic burden of osteoporotic hip fractures provide information that can be of importance in the planning and design of preventive strategies. © 2014 KUMS, All rights reserved.

Fracture strength of different soldered and welded orthodontic joining configurations with and without filling material.

PubMed

Bock, Jens Johannes; Bailly, Jacqueline; Gernhardt, Christian Ralf; Fuhrmann, Robert Andreas Werner

2008-01-01

The aim of this study was to compare the mechanical strength of different joints made by conventional brazing, TIG and laser welding with and without filling material. Five standardized joining configurations of orthodontic wire in spring hard quality were used: round, cross, 3 mm length, 9 mm length and 7 mm to orthodontic band. The joints were made by five different methods: brazing, tungsten inert gas (TIG) and laser welding with and without filling material. For the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced, totalizing 240. The fracture strengths were measured with a universal testing machine (Zwick 005). Data were analyzed by ANOVA (p=0.05) and Bonferroni post hoc test (p=0.05). In all cases, brazing joints were ruptured on a low level of fracture strength (186-407 N). Significant differences between brazing and TIG or laser welding (p<0.05, Bonferroni post hoc test) were found in each joint configuration. The highest fracture strength means were observed for laser welding with filling material and 3 mm joint length (998 N). Using filling materials, there was a clear tendency to higher mean values of fracture strength in TIG and laser welding. However, statistically significant differences were found only in the 9-mm long joints (p<0.05, Bonferroni post hoc test). In conclusion, the fracture strength of welded joints was positively influenced by the additional use of filling material. TIG welding was comparable to laser welding except for the impossibility of joining orthodontic wire with orthodontic band.

FRACTURE STRENGTH OF DIFFERENT SOLDERED AND WELDED ORTHODONTIC JOINING CONFIGURATIONS WITH AND WITHOUT FILLING MATERIAL

PubMed Central

Bock, Jens Johannes; Bailly, Jacqueline; Gernhardt, Christian Ralf; Fuhrmann, Robert Andreas Werner

2008-01-01

The aim of this study was to compare the mechanical strength of different joints made by conventional brazing, TIG and laser welding with and without filling material. Five standardized joining configurations of orthodontic wire in spring hard quality were used: round, cross, 3 mm length, 9 mm length and 7 mm to orthodontic band. The joints were made by five different methods: brazing, tungsten inert gas (TIG) and laser welding with and without filling material. For the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced, totalizing 240. The fracture strengths were measured with a universal testing machine (Zwick 005). Data were analyzed by ANOVA (p=0.05) and Bonferroni post hoc test (p=0.05). In all cases, brazing joints were ruptured on a low level of fracture strength (186-407 N). Significant differences between brazing and TIG or laser welding (p<0.05, Bonferroni post hoc test) were found in each joint configuration. The highest fracture strength means were observed for laser welding with filling material and 3 mm joint length (998 N). Using filling materials, there was a clear tendency to higher mean values of fracture strength in TIG and laser welding. However, statistically significant differences were found only in the 9-mm long joints (p<0.05, Bonferroni post hoc test). In conclusion, the fracture strength of welded joints was positively influenced by the additional use of filling material. TIG welding was comparable to laser welding except for the impossibility of joining orthodontic wire with orthodontic band. PMID:19089229

Anatomy of the larynx and pharynx: effects of age, gender and height revealed by multidetector computed tomography.

PubMed

Inamoto, Y; Saitoh, E; Okada, S; Kagaya, H; Shibata, S; Baba, M; Onogi, K; Hashimoto, S; Katada, K; Wattanapan, P; Palmer, J B

2015-09-01

Although oropharyngeal and laryngeal structures are essential for swallowing, the three-dimensional (3D) anatomy is not well understood, due in part to limitations of available measuring techniques. This study uses 3D images acquired by 320-row area detector computed tomography ('320-ADCT'), to measure the pharynx and larynx and to investigate the effects of age, gender and height. Fifty-four healthy volunteers (30 male, 24 female, 23-77 years) underwent one single-phase volume scan (0.35 s) with 320-ADCT during resting tidal breathing. Six measurements of the pharynx and two of larynx were performed. Bivariate statistical methods were used to analyse the effects of gender, age and height on these measurements. Length and volume were significantly larger for men than for women for every measurement (P < 0.05) and increased with height (P < 0.05). Multiple regression analysis was performed to understand the interactions of gender, height and age. Gender, height and age each had significant effects on certain values. The volume of the larynx and hypopharynx was significantly affected by height and age. The length of pharynx was associated with gender and age. Length of the vocal folds and distance from the valleculae to the vocal folds were significantly affected by gender (P < 0.05). These results suggest that age, gender and height have independent and interacting effects on the morphology of the pharynx and larynx. Three-dimensional imaging and morphometrics using 320-ADCT are powerful tools for efficiently and reliably observing and measuring the pharynx and larynx. © 2015 John Wiley & Sons Ltd.

Group invariant solution for a pre-existing fracture driven by a power-law fluid in permeable rock

NASA Astrophysics Data System (ADS)

Fareo, A. G.; Mason, D. P.

2016-06-01

Group invariant analytical and numerical solutions for the evolution of a two-dimensional fracture with nonzero initial length in permeable rock and driven by an incompressible non-Newtonian fluid of power-law rheology are obtained. The effect of fluid leak-off on the evolution of the power-law fluid fracture is investigated.

Biomechanical evaluation of injury severity associated with patient falls from bed.

PubMed

Bowers, Bonnie; Lloyd, John; Lee, W; Powell-Cope, G; Baptiste, A

2008-01-01

This study investigated the severity of injuries associated with falling from bed and the effectiveness of injury-prevention strategies. Injury criteria were calculated for head- and feet-first falls from six bed heights onto a tiled surface and floor mat. These values indicated a 25% chance of experiencing a serious head injury as a result of falling feet-first from a bed height of 97.5 cm onto a tiled surface. Risk of injury increased to 40% when extrapolated for the height added by bedrails. Using a floor mat decreased this risk to less than 1% for bedrail height for feet-first falls. Calculated impact forces indicated a risk of skull fracture when hitting the tiled surface. Floor mats and height-adjustable beds positioned to the lowest height should be used to decrease the risk of injury associated with falling from bed.

Is the permeability of naturally fractured rocks scale dependent?

NASA Astrophysics Data System (ADS)

Azizmohammadi, Siroos; Matthäi, Stephan K.

2017-09-01

The equivalent permeability, keq of stratified fractured porous rocks and its anisotropy is important for hydrocarbon reservoir engineering, groundwater hydrology, and subsurface contaminant transport. However, it is difficult to constrain this tensor property as it is strongly influenced by infrequent large fractures. Boreholes miss them and their directional sampling bias affects the collected geostatistical data. Samples taken at any scale smaller than that of interest truncate distributions and this bias leads to an incorrect characterization and property upscaling. To better understand this sampling problem, we have investigated a collection of outcrop-data-based Discrete Fracture and Matrix (DFM) models with mechanically constrained fracture aperture distributions, trying to establish a useful Representative Elementary Volume (REV). Finite-element analysis and flow-based upscaling have been used to determine keq eigenvalues and anisotropy. While our results indicate a convergence toward a scale-invariant keq REV with increasing sample size, keq magnitude can have multi-modal distributions. REV size relates to the length of dilated fracture segments as opposed to overall fracture length. Tensor orientation and degree of anisotropy also converge with sample size. However, the REV for keq anisotropy is larger than that for keq magnitude. Across scales, tensor orientation varies spatially, reflecting inhomogeneity of the fracture patterns. Inhomogeneity is particularly pronounced where the ambient stress selectively activates late- as opposed to early (through-going) fractures. While we cannot detect any increase of keq with sample size as postulated in some earlier studies, our results highlight a strong keq anisotropy that influences scale dependence.

Influence of rotational speed on the cyclic fatigue of rotary nickel-titanium endodontic instruments.

PubMed

Lopes, Hélio P; Ferreira, Alessandra A P; Elias, Carlos N; Moreira, Edson J L; de Oliveira, Júlio C Machado; Siqueira, José F

2009-07-01

During the preparation of curved canals, rotary nickel-titanium (NiTi) instruments are subjected to cyclic fatigue, which can lead to instrument fracture. Although several factors may influence the cyclic fatigue resistance of instruments, the role of the rotational speed remains uncertain. This study was intended to evaluate the effects of rotational speed on the number of cycles to fracture of rotary NiTi instruments. ProTaper Universal instruments F3 and F4 (Maillefer SA, Ballaigues, Switzerland) were used in an artificial curved canal under rotational speeds of 300 rpm or 600 rpm. The artificial canal was made of stainless steel, with an inner diameter of 1.5 mm, total length of 20 mm, and arc at the end with a curvature radius of 6 mm. The arc length was 9.4 mm and 10.6 mm on the straight part. The number of cycles required to fracture was recorded. Fractured surfaces and the helical shafts of the fractured instruments were analyzed by scanning electron microscopy. The results showed approximately a 30% reduction in the observed number of cycles to fracture as rotational speed was increased from 300 to 600 RPM (p < 0.05). The morphology of the fractured surface was always of ductile type, and no plastic deformation was observed on the helical shaft of fractured instruments. The present findings for both F3 and F4 ProTaper instruments revealed that the increase in rotational speed significantly reduced the number of cycles to fracture.

Biomechanical Evaluation of Standard Versus Extended Proximal Fixation Olecranon Plates for Fixation of Olecranon Fractures.

PubMed

Boden, Allison L; Daly, Charles A; Dalwadi, Poonam P; Boden, Stephanie A; Hutton, William C; Muppavarapu, Raghuveer C; Gottschalk, Michael B

2018-01-01

Small olecranon fractures present a significant challenge for fixation, which has resulted in development of plates with proximal extension. Olecranon-specific plates with proximal extensions are widely thought to offer superior fixation of small proximal fragments but have distinct disadvantages: larger dissection, increased hardware prominence, and the increased possibility of impingement. Previous biomechanical studies of olecranon fracture fixation have compared methods of fracture fixation, but to date there have been no studies defining olecranon plate fixation strength for standard versus extended olecranon plates. The purpose of this study is to evaluate the biomechanical utility of the extended plate for treatment of olecranon fractures. Sixteen matched pairs of fresh-frozen human cadaveric elbows were used. Of the 16, 8 matched pairs received a transverse osteotomy including 25% and 8 including 50% of the articular surface on the proximal fragment. One elbow from each pair was randomly assigned to a standard-length plate, and the other elbow in the pair received the extended-length plate, for fixation of the fracture. The ulnae were cyclically loaded and subsequently loaded to failure, with ultimate load, number of cycles, and gap formation recorded. There was no statistically significant difference between the standard and extended fixation plates in simple transverse fractures at either 25% or 50% from the proximal most portion of the articular surface of the olecranon. Standard fixation plates are sufficient for the fixation of small transverse fractures, but caution should be utilized particularly with comminution and nontransverse fracture patterns.

[Treatment of pediatric distal femur fractures by external fixator combined with limited internal fixation].

PubMed

Wei, Sheng-wang; Shi, Zhan-ying; Hu, Ju-zheng; Wu, Hao

2016-03-01

To discuss the clinical effects of external fixator combined with limited internal fixation in the treatment of pediatric distal femur fractures. From January 2008 to June 2014, 17 children of distal femur fractures were treated by external fixator combined with limited internal fixation. There were 12 males and 5 females, aged from 6 to 13 years old with an average of 10.2 years, ranged in the course of disease from 1 h to 2 d. Preoperative diagnoses were confirmed by X-ray films in all children. There were 11 patients with supracondylar fracture , and 6 patients with intercondylar comminuted fracture. According to AO/ASIF classification, 9 fractures were type A1, 5 cases were type A2,and 3 cases were type C1. The intraoperative and postoperative complications, postoperative radiological examination, lower limbs length and motion of knee joints were observed. Knee joint function was assessed by KSS score. All the patients were followed up from 6 to 38 months with an average of 24.4 months. No nerve or blood vessel injury was found. One case complicated with the external fixation loosening, 2 cases with the infection of pin hole and 3 cases with the leg length discrepancy. Knee joint mobility and length measurement (compared with the contralateral), the average limited inflexion was 10 degrees (0 degrees to 20 degrees), the average limited straight was 4 degrees (0 degrees to 10), the average varus or valgus angle was 3 degrees (0 degrees to 5 degrees). KSS of the injured side was (96.4 +/- 5.0) points at final follow-up, 16 cases got excellent results and 1 good. All fractures obtained healing and no epiphyseal closed early was found. External fixator combined with limited internal fixation has advantages of simple operation, reliable fixation, early functional exercise in treating pediatric distal femurs fractures.

A two-concentric-loop iterative method in estimation of displacement height and roughness length for momentum and sensible heat.

PubMed

Zhao, Wenguang; Qualls, Russell J; Berliner, Pedro R

2008-11-01

A two-concentric-loop iterative (TCLI) method is proposed to estimate the displacement height and roughness length for momentum and sensible heat by using the measurements of wind speed and air temperature at two heights, sensible heat flux above the crop canopy, and the surface temperature of the canopy. This method is deduced theoretically from existing formulae and equations. The main advantage of this method is that data measured not only under near neutral conditions, but also under unstable and slightly stable conditions can be used to calculate the scaling parameters. Based on the data measured above an Acacia Saligna agroforestry system, the displacement height (d0) calculated by the TCLI method and by a conventional method are compared. Under strict neutral conditions, the two methods give almost the same results. Under unstable conditions, d0 values calculated by the conventional method are systematically lower than those calculated by the TCLI method, with the latter exhibiting only slightly lower values than those seen under strictly neutral conditions. Computation of the average values of the scaling parameters for the agroforestry system showed that the displacement height and roughness length for momentum are 68% and 9.4% of the average height of the tree canopy, respectively, which are similar to percentages found in the literature. The calculated roughness length for sensible heat is 6.4% of the average height of the tree canopy, a little higher than the percentages documented in the literature. When wind direction was aligned within 5 degrees of the row direction of the trees, the average displacement height calculated was about 0.6 m lower than when the wind blew across the row direction. This difference was statistically significant at the 0.0005 probability level. This implies that when the wind blows parallel to the row direction, the logarithmic profile of wind speed is shifted lower to the ground, so that, at a given height, the wind speeds are faster than when the wind blows perpendicular to the row direction.

Effects of Wheelchair Seat-height Settings on Alternating Lower Limb Propulsion With Both Legs.

PubMed

Murata, Tomoyuki; Asami, Toyoko; Matsuo, Kiyomi; Kubo, Atsuko; Okigawa, Etsumi

2014-01-01

This study investigated the effects of seat-height settings of wheelchairs with alternating propulsion with both legs. Seven healthy individuals with no orthopedic disease participated. Flexion angles at initial contact (FA-IC) of each joint, range of motion during propulsion period (ROM-PP), and ground reaction force (GRF) were measured using a three dimensional motion capture system and force plates, and compared with different seat-height settings. Statistically significant relationships were found between seat-height and speed, stride length, knee FA-IC, ankle FA-IC, hip ROM-PP, vertical ground reaction force (VGRF), and anterior posterior ground reaction force (APGRF). Speed, hip ROM-PP, VGRF and APGRF increased as the seat-height was lowered. This effect diminished when the seat-height was set below -40 mm. VGRF increased as the seat-height was lowered. The results suggest that the seat-height effect can be attributed to hip ROM-PP; therefore, optimal foot propulsion cannot be achieved when the seat height is set either too high or too low. Efficient foot propulsion of the wheelchair can be achieved by setting the seat height to lower leg length according to a combination of physical characteristics, such as the user's physical functions, leg muscles, and range of motion.

Association between breast feeding and growth: the Boyd-Orr cohort study.

PubMed

Martin, R M; Smith, G Davey; Mangtani, P; Frankel, S; Gunnell, D

2002-11-01

To investigate the association of breast feeding with height and body mass index in childhood and adulthood. Historical cohort study, based on long term follow up of the Carnegie (Boyd-Orr) survey of diet and health in pre-war Britain (1937-1939). Sixteen urban and rural districts in Britain. A total of 4999 children from 1352 families were surveyed in 1937-1939. Information on infant feeding and childhood anthropometry was available for 2995 subjects. Mean differences in childhood and adult anthropometry between breast and bottle fed subjects. Breast feeding was associated with the survey district, greater household income, and food expenditure, but not with number of children in the household, birth order, or social class. In childhood, breast fed subjects were significantly taller than bottle fed subjects after controlling for socioeconomic variables. The mean height difference among boys was 0.20 standard deviation (SD) (95% confidence interval (CI) 0.07 to 0.32), and among girls it was 0.14 SD (95% CI 0.02 to 0.27). Leg length, but not trunk length, was the component of height associated with breast feeding. In males, breast feeding was associated with greater adult height (difference: 0.34 SD, 95% CI 0.13 to 0.55); of the two components of height, leg length (0.26 SD, 95% CI 0.02 to 0.50) was more strongly related to breast feeding than trunk length (0.16 SD, 95% CI -0.04 to 0.35). Height and leg length differences were in the same direction but smaller among adult females. There was no association between breast feeding and body mass index in childhood or adulthood. Compared with bottle fed infants, infants breast fed in the 1920s and 1930s were taller in childhood and adulthood. As stature is associated with health and life expectancy, the possible long term impact of infant feeding on adult mortality patterns merits further investigation.

Modeling Outburst Flooding as a Turbulent Hydraulic Fracture Parallel to a Nearby Free Surface

NASA Astrophysics Data System (ADS)

Tsai, V. C.; Rice, J. R.

2009-12-01

Meltwater generated at the surface and base of glaciers and ice sheets is known to have a large impact on how ice masses behave dynamically, but much is still unknown about the physical processes responsible for how this meltwater drains out of the glacier. For example, little attention has been paid to short-timescale processes like turbulent hydraulic fracture, which is likely an important mechanism by which drainage channels initially form when water pressures are high. In recent work (Tsai and Rice [Fall AGU, 2008; JGR subm., 2009]), we have constructed a model of this turbulent hydraulic fracture process in which over-pressurized water is assumed to flow turbulently through a crack, leading to crack growth. However, one important limitation of this prior work is that it only strictly applies in the limit of short crack length 2L compared to glacier height H, whereas relevant observations of supraglacial lake drainage, jokulhlaups and sub-glacial lake-to-lake transport episodes do not fall in this regime. Here, we improve somewhat upon this model by explicitly accounting for a nearby free surface. We accomplish this by applying the approach of Erdogan et al. [Meth. Anal. Sol. Crack Prob., 1973] to numerically calculate elastic displacements consistent with crack pressure distribution for a crack near a free surface, and use these results as before to simultaneously satisfy the governing fluid, elastic and fracture equations. Our results are analogous to the zero fracture toughness results of Zhang et al. [Int. J. Numer. Anal. Meth. Geomech., 2005], but applied to the case of turbulent flow rather than laminar flow of a Newtonian viscous fluid. Our new results clarify the importance of the free surface and potentially explain discrepancies between our previous modeling results and observations of supraglacial lake drainage by Das et al. [Science, 2008]. However, the numerical challenges increase as 2L becomes comparable to or much larger than H. We hope to ultimately develop simpler analyses for that range which make use of (visco)elastic plate theory at positions along the uplifted ice sheet that are remote from the fracturing front. This approach may also be of interest for tidal interactions with the ice-shelf grounding line location.

Modeling Outburst Flooding as a Turbulent Hydraulic Fracture Parallel to a Nearby Free Surface

NASA Astrophysics Data System (ADS)

Tsai, Victor; Rice, James

2010-05-01

Meltwater generated at the surface and base of glaciers and ice sheets is known to have a large impact on how ice masses behave dynamically, but much is still unknown about the physical processes responsible for how this meltwater drains out of the glacier. For example, little attention has been paid to short-timescale processes like turbulent hydraulic fracture, which is likely an important mechanism by which drainage channels initially form when water pressures are high. In recent work (Tsai and Rice [Fall AGU, 2008; JGR subm., 2009]), we have constructed a model of this turbulent hydraulic fracture process in which over-pressurized water is assumed to flow turbulently through a crack, leading to crack growth. However, one important limitation of this prior work is that it only strictly applies in the limit of short crack length, 2L, compared to glacier height, H, whereas relevant observations of supraglacial lake drainage, jokulhlaups and sub-glacial lake-to-lake transport episodes do not fall in this regime. Here, we improve somewhat upon this model by explicitly accounting for a nearby free surface. We accomplish this by applying the approach of Erdogan et al. [Meth. Anal. Sol. Crack Prob., 1973] to numerically calculate elastic displacements consistent with crack pressure distribution for a crack near a free surface, and use these results as before to simultaneously satisfy the governing fluid, elastic and fracture equations. Our results are analogous to the zero fracture toughness results of Zhang et al. [Int. J. Numer. Anal. Meth. Geomech., 2005], but applied to the case of turbulent flow rather than laminar flow of a Newtonian viscous fluid. Our new results clarify the importance of the free surface and potentially explain discrepancies between our previous modeling results and observations of supraglacial lake drainage by Das et al. [Science, 2008]. However, the numerical challenges increase as 2L becomes comparable to or much larger than H. We hope to ultimately develop simpler analyses for that range which make use of (visco)elastic plate theory at positions along the uplifted ice sheet that are remote from the fracturing front. This approach may also be of interest for tidal interactions with the ice-shelf grounding line location.

Abdominal girth, vertebral column length, and spread of spinal anesthesia in 30 minutes after plain bupivacaine 5 mg/mL.

PubMed

Zhou, Qing-he; Xiao, Wang-pin; Shen, Ying-yan

2014-07-01

The spread of spinal anesthesia is highly unpredictable. In patients with increased abdominal girth and short stature, a greater cephalad spread after a fixed amount of subarachnoidally administered plain bupivacaine is often observed. We hypothesized that there is a strong correlation between abdominal girth/vertebral column length and cephalad spread. Age, weight, height, body mass index, abdominal girth, and vertebral column length were recorded for 114 patients. The L3-L4 interspace was entered, and 3 mL of 0.5% plain bupivacaine was injected into the subarachnoid space. The cephalad spread (loss of temperature sensation and loss of pinprick discrimination) was assessed 30 minutes after intrathecal injection. Linear regression analysis was performed for age, weight, height, body mass index, abdominal girth, vertebral column length, and the spread of spinal anesthesia, and the combined linear contribution of age up to 55 years, weight, height, abdominal girth, and vertebral column length was tested by multiple regression analysis. Linear regression analysis showed that there was a significant univariate correlation among all 6 patient characteristics evaluated and the spread of spinal anesthesia (all P < 0.039) except for age and loss of temperature sensation (P > 0.068). Multiple regression analysis showed that abdominal girth and the vertebral column length were the key determinants for spinal anesthesia spread (both P < 0.0001), whereas age, weight, and height could be omitted without changing the results (all P > 0.059, all 95% confidence limits < 0.372). Multiple regression analysis revealed that the combination of a patient's 5 general characteristics, especially abdominal girth and vertebral column length, had a high predictive value for the spread of spinal anesthesia after a given dose of plain bupivacaine.

Epigenetic and genetic components of height regulation.

PubMed

Benonisdottir, Stefania; Oddsson, Asmundur; Helgason, Agnar; Kristjansson, Ragnar P; Sveinbjornsson, Gardar; Oskarsdottir, Arna; Thorleifsson, Gudmar; Davidsson, Olafur B; Arnadottir, Gudny A; Sulem, Gerald; Jensson, Brynjar O; Holm, Hilma; Alexandersson, Kristjan F; Tryggvadottir, Laufey; Walters, G Bragi; Gudjonsson, Sigurjon A; Ward, Lucas D; Sigurdsson, Jon K; Iordache, Paul D; Frigge, Michael L; Rafnar, Thorunn; Kong, Augustine; Masson, Gisli; Helgason, Hannes; Thorsteinsdottir, Unnur; Gudbjartsson, Daniel F; Sulem, Patrick; Stefansson, Kari

2016-11-16

Adult height is a highly heritable trait. Here we identified 31.6 million sequence variants by whole-genome sequencing of 8,453 Icelanders and tested them for association with adult height by imputing them into 88,835 Icelanders. Here we discovered 13 novel height associations by testing four different models including parent-of-origin (|β|=0.4-10.6 cm). The minor alleles of three parent-of-origin signals associate with less height only when inherited from the father and are located within imprinted regions (IGF2-H19 and DLK1-MEG3). We also examined the association of these sequence variants in a set of 12,645 Icelanders with birth length measurements. Two of the novel variants, (IGF2-H19 and TET1), show significant association with both adult height and birth length, indicating a role in early growth regulation. Among the parent-of-origin signals, we observed opposing parental effects raising questions about underlying mechanisms. These findings demonstrate that common variations affect human growth by parental imprinting.

Correlation between Condylar Fracture Pattern after Parasymphyseal Impact and Condyle Morphological Features: A Retrospective Analysis of 107 Chinese Patients.

PubMed

Han, Lu; Long, Ting; Tang, Wei; Liu, Lei; Jing, Wei; Tian, Wei-Dong; Long, Jie

2017-02-20

The treatment of the condylar fractures is difficult. Factors that result in the fractures are complex. The objective of this morphometric study was to investigate the relationship between condylar fracture patterns and condylar morphological characteristics. We conducted a retrospective analysis of 107 patients admitted to the West China Hospital of Stomatology for bilateral condylar fractures caused by parasymphyseal impact. The patients were divided into five groups according to the type of condylar fracture. Ten parameters were evaluated on three-dimensional (3D) reconstruction mandible models through the Mimics 16.0 (Materialize Leuven, Belgium) anthropometry toolkit. Each parameter of the 3D models was analyzed using multivariate analysis. Multinomial logistic regression analyses were used to examine the relationships between the five groups. The results showed that the differences of condylar head width (M1), condylar neck width (M3), the ratio of condylar head width to condylar anteroposterior diameter (M1/M2), the ratio of condylar head width to condylar neck width (M1/M3), the ratio of condylar height to ramus height (M8/M7), and mandibular angle (M10) were statistically significant (p < 0.05). Type A condylar head fractures were positively associated with M1 (compared to Type B: OR =1.627, 95% CI: 1.123, 2.359; compared to Type C: OR = 1.705, 95% CI: 1.170, 2.484) and M1/M2 (compared to Type B: OR =1.034, 95% CI: 0.879, 2.484). Type B condylar head fractures were negatively associated with M10 (compared to Type C: OR = 0.909, 95% CI: 0.821, 1.007). Condylar neck fractures were negatively associated with M3 (compared to condylar head: OR = 0.382, CI: 0.203, 0.720 ; compared to condylar base: OR = 0.436, 95% CI: 0.218, 0.874), and positively associated with M1/M3 (compared to condylar head: OR = 1.229, 95% CI: 1.063, 1.420 compared to condylar base: OR = 1.223, 95% CI: 1.034, 1.447). Condylar base fractures were positively associated with M10 (OR = 1.095, 95% CI: 1.008, 1.189) and negatively associated with M8/M7 (OR = 0.855, 95% CI: 0.763, 0.959) as compared with condylar head fractures. Condylar fracture pattern is associated with the anatomical features of the condyles when a fracture occurs from parasymphyseal impact.

Correlation between Condylar Fracture Pattern after Parasymphyseal Impact and Condyle Morphological Features: A Retrospective Analysis of 107 Chinese Patients

PubMed Central

Han, Lu; Long, Ting; Tang, Wei; Liu, Lei; Jing, Wei; Tian, Wei-Dong; Long, Jie

2017-01-01

Background: The treatment of the condylar fractures is difficult. Factors that result in the fractures are complex. The objective of this morphometric study was to investigate the relationship between condylar fracture patterns and condylar morphological characteristics. Methods: We conducted a retrospective analysis of 107 patients admitted to the West China Hospital of Stomatology for bilateral condylar fractures caused by parasymphyseal impact. The patients were divided into five groups according to the type of condylar fracture. Ten parameters were evaluated on three-dimensional (3D) reconstruction mandible models through the Mimics 16.0 (Materialize Leuven, Belgium) anthropometry toolkit. Each parameter of the 3D models was analyzed using multivariate analysis. Multinomial logistic regression analyses were used to examine the relationships between the five groups. Results: The results showed that the differences of condylar head width (M1), condylar neck width (M3), the ratio of condylar head width to condylar anteroposterior diameter (M1/M2), the ratio of condylar head width to condylar neck width (M1/M3), the ratio of condylar height to ramus height (M8/M7), and mandibular angle (M10) were statistically significant (p < 0.05). Type A condylar head fractures were positively associated with M1 (compared to Type B: OR =1.627, 95% CI: 1.123, 2.359; compared to Type C: OR = 1.705, 95% CI: 1.170, 2.484) and M1/M2 (compared to Type B: OR =1.034, 95% CI: 0.879, 2.484). Type B condylar head fractures were negatively associated with M10 (compared to Type C: OR = 0.909, 95% CI: 0.821, 1.007). Condylar neck fractures were negatively associated with M3 (compared to condylar head: OR = 0.382, CI: 0.203, 0.720; compared to condylar base: OR = 0.436, 95% CI: 0.218, 0.874), and positively associated with M1/M3 (compared to condylar head: OR = 1.229, 95% CI: 1.063, 1.420 compared to condylar base: OR = 1.223, 95% CI: 1.034, 1.447). Condylar base fractures were positively associated with M10 (OR = 1.095, 95% CI: 1.008, 1.189) and negatively associated with M8/M7 (OR = 0.855, 95% CI: 0.763, 0.959) as compared with condylar head fractures. Conclusions: Condylar fracture pattern is associated with the anatomical features of the condyles when a fracture occurs from parasymphyseal impact. PMID:28218215

Prediction of anthropometric foot characteristics in children.

PubMed

Morrison, Stewart C; Durward, Brian R; Watt, Gordon F; Donaldson, Malcolm D C

2009-01-01

The establishment of growth reference values is needed in pediatric practice where pathologic conditions can have a detrimental effect on the growth and development of the pediatric foot. This study aims to use multiple regression to evaluate the effects of multiple predictor variables (height, age, body mass, and gender) on anthropometric characteristics of the peripubescent foot. Two hundred children aged 9 to 12 years were recruited, and three anthropometric measurements of the pediatric foot were recorded (foot length, forefoot width, and navicular height). Multiple regression analysis was conducted, and coefficients for gender, height, and body mass all had significant relationships for the prediction of forefoot width and foot length (P < or = .05, r > or = 0.7). The coefficients for gender and body mass were not significant for the prediction of navicular height (P > or = .05), whereas height was (P < or = .05). Normative growth reference values and prognostic regression equations are presented for the peripubescent foot.

Peri-implant bone length changes and survival rates of implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height.

PubMed

Kim, Hae-Young; Yang, Jin-Yong; Chung, Bo-Yoon; Kim, Jeong Chan; Yeo, In-Sung

2013-04-01

The aim of this study was to measure the peri-implant bone length surrounding implants that penetrate the sinus membrane at the posterior maxilla and to evaluate the survival rate of these implants. Treatment records and orthopantomographs of 39 patients were reviewed and analyzed. The patients had partial edentulism at the posterior maxilla and limited vertical bone height below the maxillary sinus. Implants were inserted into the posterior maxilla, penetrating the sinus membrane. Four months after implant insertion, provisional resin restorations were temporarily cemented to the abutments and used for one month. Then, a final impression was taken at the abutment level, and final cement-retained restorations were delivered with mutually protected occlusion. The complications from the implant surgery were examined, the number of failed implants was counted, and the survival rate was calculated. The peri-implant bone lengths were measured using radiographs. The changes in initial and final peri-implant bone lengths were statistically analyzed. Nasal bleeding occurred after implant surgery in three patients. No other complications were found. There were no failures of the investigated implants, resulting in a survival rate of 100%. Significantly more bone gain around the implants (estimated difference=-0.6 mm, P=0.025) occurred when the initial residual bone height was less than 5 mm compared to the >5 mm groups. No significant change in peri-implant bone length was detected when the initial residual bone height was 5 mm or larger. This study suggests that implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height may be safe and functional.

Polymethylmethacrylate distribution is associated with recompression after vertebroplasty or kyphoplasty for osteoporotic vertebral compression fractures: A retrospective study.

PubMed

Hou, Yu; Yao, Qi; Zhang, Genai; Ding, Lixiang; Huang, Hui

2018-01-01

Osteoporotic vertebral compression fracture, always accompanied with pain and height loss of vertebral body, has a significant negative impact on life quality of patients. Vertebroplasty or kyphoplasty is minimal invasive techniques to reconstruct the vertebral height and prevent further collapse of the fractured vertebrae by injecting polymethylmethacrylate into vertebral body. However, recompression of polymethylmethacrylate augmented vertebrae with significant vertebral height loss and aggressive local kyphotic was observed frequently after VP or KP. The purpose of this study was to investigate the effect of polymethylmethacrylate distribution on recompression of the vertebral body after vertebroplasty or kyphoplasty surgery for osteoporotic vertebral compression fracture. A total of 281 patients who were diagnosed with vertebral compression fracture (T5-L5) from June 2014 to June 2016 and underwent vertebroplasty or kyphoplasty by polymethylmethacrylate were retrospectively analyzed. The X-ray films at 1 day and 12 months after surgery were compared to evaluate the recompression of operated vertebral body. Patients were divided into those without recompression (non-recompression group) and those with recompression (recompression group). Polymethylmethacrylate distribution pattern, including location and relationship to endplates, was compared between the two groups by lateral X-ray film. Multivariate logistic regression analysis was performed to assess the potential risk factors associated with polymethylmethacrylate distribution for recompression. One hundred and six (37.7%) patients experienced recompression after surgery during the follow-up period. The polymethylmethacrylate distributed in the middle of vertebral body showed significant differences between two groups. In non-recompression group, the polymethylmethacrylate in the middle portion of vertebral body were closer to endplates than that in the recompression group (upper: t = 31.41, p<0.001; lower: t = 12.19, p<0.001). The higher percentage of the height of polymethylmethacrylate in the middle portion of vertebral body indicates the lower risk of recompression (odds ratio [OR]<0.01, p<0.001). The recompression group and non-recompression group showed significant difference in "contacted" polymethylmethacrylate distribution pattern (polymethylmethacrylate contacted to the both upper/lower endplates) (χ2 = 66.23, p<0.001). The vertebra with a "contacted" polymethylmethacrylate distribution pattern has lower risk of recompression (OR = 0.09, p<0.001). Either more polymethylmethacrylate in the middle portion of vertebral body or "contacted" polymethylmethacrylate distribution pattern had a significantly less incidence of recompression. The findings indicated that the control of polymethylmethacrylate distribution during surgery may reduce the risks of recompression after vertebroplasty or kyphoplasty.

Polymethylmethacrylate distribution is associated with recompression after vertebroplasty or kyphoplasty for osteoporotic vertebral compression fractures: A retrospective study

PubMed Central

Yao, Qi; Zhang, Genai; Ding, Lixiang; Huang, Hui

2018-01-01

Background Osteoporotic vertebral compression fracture, always accompanied with pain and height loss of vertebral body, has a significant negative impact on life quality of patients. Vertebroplasty or kyphoplasty is minimal invasive techniques to reconstruct the vertebral height and prevent further collapse of the fractured vertebrae by injecting polymethylmethacrylate into vertebral body. However, recompression of polymethylmethacrylate augmented vertebrae with significant vertebral height loss and aggressive local kyphotic was observed frequently after VP or KP. The purpose of this study was to investigate the effect of polymethylmethacrylate distribution on recompression of the vertebral body after vertebroplasty or kyphoplasty surgery for osteoporotic vertebral compression fracture. Methods A total of 281 patients who were diagnosed with vertebral compression fracture (T5-L5) from June 2014 to June 2016 and underwent vertebroplasty or kyphoplasty by polymethylmethacrylate were retrospectively analyzed. The X-ray films at 1 day and 12 months after surgery were compared to evaluate the recompression of operated vertebral body. Patients were divided into those without recompression (non-recompression group) and those with recompression (recompression group). Polymethylmethacrylate distribution pattern, including location and relationship to endplates, was compared between the two groups by lateral X-ray film. Multivariate logistic regression analysis was performed to assess the potential risk factors associated with polymethylmethacrylate distribution for recompression. Results One hundred and six (37.7%) patients experienced recompression after surgery during the follow-up period. The polymethylmethacrylate distributed in the middle of vertebral body showed significant differences between two groups. In non-recompression group, the polymethylmethacrylate in the middle portion of vertebral body were closer to endplates than that in the recompression group (upper: t = 31.41, p<0.001; lower: t = 12.19, p<0.001). The higher percentage of the height of polymethylmethacrylate in the middle portion of vertebral body indicates the lower risk of recompression (odds ratio [OR]<0.01, p<0.001). The recompression group and non-recompression group showed significant difference in “contacted” polymethylmethacrylate distribution pattern (polymethylmethacrylate contacted to the both upper/lower endplates) (χ2 = 66.23, p<0.001). The vertebra with a “contacted” polymethylmethacrylate distribution pattern has lower risk of recompression (OR = 0.09, p<0.001). Conclusions Either more polymethylmethacrylate in the middle portion of vertebral body or “contacted” polymethylmethacrylate distribution pattern had a significantly less incidence of recompression. The findings indicated that the control of polymethylmethacrylate distribution during surgery may reduce the risks of recompression after vertebroplasty or kyphoplasty. PMID:29856859

Estimates of volumetric bone density from projectional measurements improve the discriminatory capability of dual X-ray absorptiometry

NASA Technical Reports Server (NTRS)

Jergas, M.; Breitenseher, M.; Gluer, C. C.; Yu, W.; Genant, H. K.

1995-01-01

To determine whether estimates of volumetric bone density from projectional scans of the lumbar spine have weaker associations with height and weight and stronger associations with prevalent vertebral fractures than standard projectional bone mineral density (BMD) and bone mineral content (BMC), we obtained posteroanterior (PA) dual X-ray absorptiometry (DXA), lateral supine DXA (Hologic QDR 2000), and quantitative computed tomography (QCT, GE 9800 scanner) in 260 postmenopausal women enrolled in two trials of treatment for osteoporosis. In 223 women, all vertebral levels, i.e., L2-L4 in the DXA scan and L1-L3 in the QCT scan, could be evaluated. Fifty-five women were diagnosed as having at least one mild fracture (age 67.9 +/- 6.5 years) and 168 women did not have any fractures (age 62.3 +/- 6.9 years). We derived three estimates of "volumetric bone density" from PA DXA (BMAD, BMAD*, and BMD*) and three from paired PA and lateral DXA (WA BMD, WA BMDHol, and eVBMD). While PA BMC and PA BMD were significantly correlated with height (r = 0.49 and r = 0.28) or weight (r = 0.38 and r = 0.37), QCT and the volumetric bone density estimates from paired PA and lateral scans were not (r = -0.083 to r = 0.050). BMAD, BMAD*, and BMD* correlated with weight but not height. The associations with vertebral fracture were stronger for QCT (odds ratio [QR] = 3.17; 95% confidence interval [CI] = 1.90-5.27), eVBMD (OR = 2.87; CI 1.80-4.57), WA BMDHol (OR = 2.86; CI 1.80-4.55) and WA-BMD (OR = 2.77; CI 1.75-4.39) than for BMAD*/BMD* (OR = 2.03; CI 1.32-3.12), BMAD (OR = 1.68; CI 1.14-2.48), lateral BMD (OR = 1.88; CI 1.28-2.77), standard PA BMD (OR = 1.47; CI 1.02-2.13) or PA BMC (OR = 1.22; CI 0.86-1.74). The areas under the receiver operating characteristic (ROC) curves for QCT and all estimates of volumetric BMD were significantly higher compared with standard PA BMD and PA BMC. We conclude that, like QCT, estimates of volumetric bone density from paired PA and lateral scans are unaffected by height and weight and are more strongly associated with vertebral fracture than standard PA BMD or BMC, or estimates of volumetric density that are solely based on PA DXA scans.

Femoral neck shaft angle in men with fragility fractures.

PubMed

Tuck, S P; Rawlings, D J; Scane, A C; Pande, I; Summers, G D; Woolf, A D; Francis, R M

2011-01-01

Introduction. Femoral neck shaft angle (NSA) has been reported to be an independent predictor of hip fracture risk in men. We aimed to assess the role of NSA in UK men. Methods. The NSA was measured manually from the DXA scan printout in men with hip (62, 31 femoral neck and 31 trochanteric), symptomatic vertebral (91), and distal forearm (67) fractures and 389 age-matched control subjects. Age, height, weight, and BMD (g/cm(2): lumbar spine, femoral neck, and total femur) measurements were performed. Results. There was no significant difference in mean NSA between men with femoral neck and trochanteric hip fractures, so all further analyses of hip fractures utilised the combined data. There was no difference in NSA between those with hip fractures and those without (either using the combined data or analysing trochanteric and femoral neck shaft fractures separately), nor between fracture subjects as a whole and controls. Mean NSA was smaller in those with vertebral fractures (129.2° versus 131°: P = 0.001), but larger in those with distal forearm fractures (129.8° versus 128.5°: P = 0.01). Conclusions. The conflicting results suggest that femoral NSA is not an important determinant of hip fracture risk in UK men.

Data Mining Activity for Bone Discipline: Calculating a Factor of Risk for Hip Fracture in Long-Duration Astronauts

NASA Technical Reports Server (NTRS)

Ellman, R.; Sibonga, J. D.; Bouxsein, M. L.

2010-01-01

The factor-of-risk (Phi), defined as the ratio of applied load to bone strength, is a biomechanical approach to hip fracture risk assessment that may be used to identify subjects who are at increased risk for fracture. The purpose of this project was to calculate the factor of risk in long duration astronauts after return from a mission on the International Space Station (ISS), which is typically 6 months in duration. The load applied to the hip was calculated for a sideways fall from standing height based on the individual height and weight of the astronauts. The soft tissue thickness overlying the greater trochanter was measured from the DXA whole body scans and used to estimate attenuation of the impact force provided by soft tissues overlying the hip. Femoral strength was estimated from femoral areal bone mineral density (aBMD) measurements by dual-energy x-ray absorptiometry (DXA), which were performed between 5-32 days of landing. All long-duration NASA astronauts from Expedition 1 to 18 were included in this study, where repeat flyers were treated as separate subjects. Male astronauts (n=20) had a significantly higher factor of risk for hip fracture Phi than females (n=5), with preflight values of 0.83+/-0.11 and 0.36+/-0.07, respectively, but there was no significant difference between preflight and postflight Phi (Figure 1). Femoral aBMD measurements were not found to be significantly different between men and women. Three men and no women exceeded the theoretical fracture threshold of Phi=1 immediately postflight, indicating that they would likely suffer a hip fracture if they were to experience a sideways fall with impact to the greater trochanter. These data suggest that male astronauts may be at greater risk for hip fracture than women following spaceflight, primarily due to relatively less soft tissue thickness and subsequently greater impact force.

Design study of piezoelectric energy-harvesting devices for generation of higher electrical power using a coupled piezoelectric-circuit finite element method.

PubMed

Zhu, Meiling; Worthington, Emma; Tiwari, Ashutosh

2010-01-01

This paper presents a design study on the geometric parameters of a cantilever-based piezoelectric energy-harvesting devices (EHD), which harvest energy from motion (vibration), for the purpose of scavenging more energy from ambient vibration energy sources. The design study is based on the coupled piezoelectric-circuit finite element method (CPCFEM), previously presented by Dr. Zhu. This model can calculate the power output of piezoelectric EHDS directly connected to a load resistor and is used in this paper to obtain the following simulation results for variations in geometric parameters such as the beam length, width and thickness, and the mass length, width, and height: 1) the current flowing through and the voltage developed across the load resistor, 2) the power dissipated by the resistor and the corresponding vibrational displacement amplitude, and 3) the resonant frequency. By studying these results, straightforward design strategies that enable the generation of more power are obtained for each geometric parameter, and a physical understanding of how each parameter affects the output power is given. It is suggested that, in designing with the aim of generating more power, the following strategies be used: 1) for the beam, a shorter length, larger width, and lower ratio of piezoelectric layer thickness to total beam thickness are preferred in the case of a fixed mass; 2) for the mass, a shortened mass length and a higher mass height are preferred in the case of variation in the mass length and the mass height with mass width and mass value remain fixed, and a wider width and small mass height are preferred in the case of variation in mass width and height (mass length and value remain fixed; and 3) for the case of a fixed total length, a shorter beam length and longer mass length are preferred. With the design strategies, output powers from the device can reach above 1 to 2 mW/cm(3), much higher than the 200 microW/cm(3) currently achieved in the published literature. This is an encouraging prospect for enabling a wider range of applications of the EHDs. In addition, physical insights into how each parameter influences output power are also discussed in detail.

Growth and nutritional status of preschool children in India: a study of two recent time periods.

PubMed

Sen, Pronab; Bharati, Susmita; Som, Suparna; Pal, Manoranjan; Bharati, Premananda

2011-06-01

Preschool children call for focused attention in India because India has the highest percentage of undernourished children in the world. To compare the growth and nutritional status of Indian preschool children for the periods 1998/99 and 2005/06, Using data on weight and length/height as well as the sociodemographic background of preschool children from the National Family Health Surveys (NFHS) from 1998/99 and 2005/06, we determined the distribution of weight and length/height and their association with sociodemographic variables. The distributions of weight and length/height around the mean remained remarkably stable over age but were much greater in India than the international norms. The rates of growth of mean weight and length/ height were far lower in India than the international norms up to the age of 2 years. The temporal trend indicates declines in the percentages of undernourished (low weight-for-age) and stunted (low height-for-age) children over the 7-year period, although the degree of improvement was far better for stunting than for underweight. Mother's educational status is the only variable that has been found to influence child nutrition. The level of mothers' education needs urgent attention with top priority to reduce the prevalence of underweight and stunting of children. This also implies that, for future benefit, girls should be given more facilities for better education. Breastfeeding and weaning practices also need special attention.

Kuhn-Tucker optimization based reliability analysis for probabilistic finite elements

NASA Technical Reports Server (NTRS)

Liu, W. K.; Besterfield, G.; Lawrence, M.; Belytschko, T.

1988-01-01

The fusion of probability finite element method (PFEM) and reliability analysis for fracture mechanics is considered. Reliability analysis with specific application to fracture mechanics is presented, and computational procedures are discussed. Explicit expressions for the optimization procedure with regard to fracture mechanics are given. The results show the PFEM is a very powerful tool in determining the second-moment statistics. The method can determine the probability of failure or fracture subject to randomness in load, material properties and crack length, orientation, and location.

The effect of bone fracture unevenness on ultrasound axial transmission measurements: A pilot 2D simulation study

NASA Astrophysics Data System (ADS)

Machado, Christiano B.; Pereira, Wagner C. A.; Padilla, Frédéric; Laugier, Pascal

2012-05-01

Ultrasound axial transmission (UAT) has been proposed to the diagnosis and follow-up of fracture healing. Some researchers have already pointed out the influence of fracture length, geometry and callus composition on the ultrasound time-of-flight and attenuation, with experimental and simulation studies. The aim of this work was to develop a pilot study on the effect of bone fracture unevenness on UAT measurements. Two-dimensional (2D) numerical simulations of ultrasound wave propagation were run using a custom-made finite-difference time domain code (SimSonic2D). Numerical models were composed of two 4-mm thick bone plates, with fracture lengths varying from 0 to 4 mm. For each case, an upward (UWun) and downward (DWun) unevenness of 0.5, 1.0 and 1.5 mm was implemented in the second plate. The 1-MHz emitter and receptor transducers were placed at 40 mm from each other, 20 mm apart from the center fracture. Two configurations were considered: 1.5 mm above the plates (for the 0-mm unevenness case) and transducers in contact with bone plate. For each situation, the time-of-flight of the first arriving signal (TOFFAS) and the FAS energy amplitude loss measured by the sound pressure level (SPLFAS) were computed. Results showed that there was a linear increase in TOFFAS with increasing fracture length, and a decrease of SPLFAS with the presence of a discontinuity. TOFFAS values were decreased with UWun (-0.87 μs for UWun = 1.5 mm), and increased with DWun (+0.99 μs for DWun = 1.5 mm). The SPLFAS increased with both UWun (+3.54 dB for UWun = 1.5 mm) and DWun (+8.15 dB for DWun = 1.5 mm). Both parameters showed the same variability. When transducers were put in contact with bone surface, fracture unevenness had no influence on TOF and SPL estimates. Previous works have already demonstrated that a fracture of 3 mm can increase TOFFAS in an order of 1 μs. Considering these preliminary results, it can be concluded that, although the variable fracture unevenness (until 1.5 mm) produced small parameters changes, and since it may not be changed significantly during the regeneration process, it may not sufficiently affect UAT measurements for an adequate diagnosis and fracture follow up.

Wave generation by fracture initiation and propagation in geomaterials with internal rotations

NASA Astrophysics Data System (ADS)

Esin, Maxim; Pasternak, Elena; Dyskin, Arcady; Xu, Yuan

2016-04-01

Crack or fracture initiation and propagation in geomaterials are sources of waves and is important in both stability and fracture (e.g. hydraulic fracture) monitoring. Many geomaterials consist of particles or other constituents capable of rotating with respect to each other, either due to the absence of the binder phase (fragmented materials) or due to extensive damage of the cement between the constituents inflicted by previous loading. In investigating the wave generated in fracturing it is important to distinguish between the cases when the fracture is instantaneously initiated to its full length or propagates from a smaller initial crack. We show by direct physical experiments and discrete element modelling of 2D arrangements of unbonded disks that under compressive load fractures are initiated instantaneously as a result of the material instability and localisation. Such fractures generate waves as a single impulse impact. When the fractures propagate, they produce a sequence of impulses associated with the propagation steps. This manifests itself as acoustic (microseismic) emission whose temporal pattern contains the information of the fracture geometry, such as fractal dimension of the fracture. The description of this process requires formulating criteria of crack growth capable of taking into account the internal rotations. We developed an analytical solution based on the Cosserat continuum where each point of body has three translational and three rotational degrees of freedom. When the Cosserat characteristic lengths are comparable with the grain sizes, the simplified equations of small-scale Cosserat continuum can be used. We established that the order of singularity of the main asymptotic term for moment stress is higher than the order of singularity for conventional stress. Therefore, the mutual rotation of particles and related bending and/or twisting of the bonds between the particles represent an unconventional mechanism of crack propagation.

Radiologic study of disc behavior following compression fracture of the thoracolumbar hinge managed by kyphoplasty: A 52-case series.

PubMed

Teyssédou, S; Saget, M; Gayet, L E; Pries, P; Brèque, C; Vendeuvre, T

2016-02-01

Kyphoplasty has proved effective for durable correction of traumatic vertebral deformity following Magerl A fracture, but subsequent behavior of the adjacent discs is unclear. The objective of the present study was to analyze evolution according to severity of initial kyphosis and quality of fracture reduction. A single-center prospective study included cases of single compression fracture of the thoracolumbar hinge managed by Kyphon Balloon Kyphoplasty with polymethylmethacrylate bone cement. Radiology focused on traumatic vertebral kyphosis (VK), disc angulation (DA) and disc height index (DHI) in the adjacent discs. Linear regression assessed the correlation between superior disc height index (SupDHI) and postoperative VK on the one hand and correction gain on the other, using the Student t test for matched pairs and Pearson correlation coefficient. Fifty-two young patients were included, with mean follow-up of 18.6 months. VK fell from 13.9° preoperatively to 8.2° at last follow-up. DHI found significant superior disc subsidence (P=0.0001) and non-significant inferior disc subsidence (P=0.116). DA showed significantly reduced superior disc lordosis (P=4*10(-5)). SupDHI correlated with VK correction (r=0.32). Preoperative VK did not correlate with radiologic degeneration of the adjacent discs. Correction of traumatic vertebral deformity avoids subsidence and loss of mechanical function in the superior adjacent disc. The underlying disc compensates for residual deformity. Balloon kyphoplasty is useful in compression fracture, providing significant reduction of traumatic vertebral deformity while conserving free and healthy adjacent discs. IV. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

[Fractures of the lower extremities in childhood : Part 2: lower leg and ankle fractures].

PubMed

Voth, M; Kremer, L; Marzi, I

2017-11-01

The treatment of pediatric patients in trauma surgery is a special situation in every aspect. For deciding on the correct treatment of fractures of the lower leg and ankle joint, various parameters, such as residual growth rate, skeletal age and height of the patient are decisive. The differences between fractures in children and adolescents are the open epiphyseal plate and the resulting residual growth. The bones of young children have a higher healing tendency and a greater potential for correction than in adolescents. Especially in the lower leg and the ankle joint, the potential for correction is decisive for the healing of fractures and for possible development of growth disorders. The limits of tolerance concerning axial malalignments and the expected spontaneous potential for correction must play an essential role for further treatment with conservative or operative therapy. This article deals with the special features of pediatric fractures of the lower leg and ankle joint.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maurer, K. D.; Bohrer, G.; Kenny, W. T.

Surface roughness parameters, namely the roughness length and displacement height, are an integral input used to model surface fluxes. However, most models assume these parameters to be a fixed property of plant functional type and disregard the governing structural heterogeneity and dynamics. In this study, we use large-eddy simulations to explore, in silico, the effects of canopy-structure characteristics on surface roughness parameters. We performed a virtual experiment to test the sensitivity of resolved surface roughness to four axes of canopy structure: (1) leaf area index, (2) the vertical profile of leaf density, (3) canopy height, and (4) canopy gap fraction.more » We found roughness parameters to be highly variable, but uncovered positive relationships between displacement height and maximum canopy height, aerodynamic canopy height and maximum canopy height and leaf area index, and eddy-penetration depth and gap fraction. We also found negative relationships between aerodynamic canopy height and gap fraction, as well as between eddy-penetration depth and maximum canopy height and leaf area index. We generalized our model results into a virtual "biometric" parameterization that relates roughness length and displacement height to canopy height, leaf area index, and gap fraction. Using a decade of wind and canopy-structure observations in a site in Michigan, we tested the effectiveness of our model-driven biometric parameterization approach in predicting the friction velocity over heterogeneous and disturbed canopies. We compared the accuracy of these predictions with the friction-velocity predictions obtained from the common simple approximation related to canopy height, the values calculated with large-eddy simulations of the explicit canopy structure as measured by airborne and ground-based lidar, two other parameterization approaches that utilize varying canopy-structure inputs, and the annual and decadal means of the surface roughness parameters at the site from meteorological observations. We found that the classical representation of constant roughness parameters (in space and time) as a fraction of canopy height performed relatively well. Nonetheless, of the approaches we tested, most of the empirical approaches that incorporate seasonal and interannual variation of roughness length and displacement height as a function of the dynamics of canopy structure produced more precise and less biased estimates for friction velocity than models with temporally invariable parameters.« less

The influence of procedure delay on resource use: a national study of patients with open tibial fracture.

PubMed

Sears, Erika Davis; Burke, James F; Davis, Matthew M; Chung, Kevin C

2013-03-01

The purpose of this study was to (1) understand national variation in delay of emergency procedures in patients with open tibial fracture at the hospital level and (2) compare length of stay and cost in patients cared for at the best- and worst-performing hospitals for delay. The authors retrospectively analyzed the 2003 to 2009 Nationwide Inpatient Sample. Adult patients with open tibial fracture were included. Hospital probability of delay in performing emergency procedures beyond the day of admission was calculated. Multilevel linear regression random-effects models were created to evaluate the relationship between the treating hospital's tendency for delay (in quartiles) and the log-transformed outcomes of length of stay and cost. The final sample included 7029 patients from 332 hospitals. Patients treated at hospitals in the fourth (worst) quartile for delay were estimated to have 12 percent (95 percent CI, 2 to 21 percent) higher cost compared with patients treated at hospitals in the first quartile. In addition, patients treated at hospitals in the fourth quartile had an estimated 11 percent (95 percent CI, 4 to 17 percent) longer length of stay compared with patients treated at hospitals in the first quartile. Patients with open tibial fracture treated at hospitals with more timely initiation of surgical care had lower cost and shorter length of stay than patients treated at hospitals with less timely initiation of care. Policies directed toward mitigating variation in care may reduce unnecessary waste.

Optimizing X-ray mirror thermal performance using matched profile cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Lin; Cocco, Daniele; Kelez, Nicholas

2015-08-07

To cover a large photon energy range, the length of an X-ray mirror is often longer than the beam footprint length for much of the applicable energy range. To limit thermal deformation of such a water-cooled X-ray mirror, a technique using side cooling with a cooled length shorter than the beam footprint length is proposed. This cooling length can be optimized by using finite-element analysis. For the Kirkpatrick–Baez (KB) mirrors at LCLS-II, the thermal deformation can be reduced by a factor of up to 30, compared with full-length cooling. Furthermore, a second, alternative technique, based on a similar principle ismore » presented: using a long, single-length cooling block on each side of the mirror and adding electric heaters between the cooling blocks and the mirror substrate. The electric heaters consist of a number of cells, located along the mirror length. The total effective length of the electric heater can then be adjusted by choosing which cells to energize, using electric power supplies. The residual height error can be minimized to 0.02 nm RMS by using optimal heater parameters (length and power density). Compared with a case without heaters, this residual height error is reduced by a factor of up to 45. The residual height error in the LCLS-II KB mirrors, due to free-electron laser beam heat load, can be reduced by a factor of ~11belowthe requirement. The proposed techniques are also effective in reducing thermal slope errors and are, therefore, applicable to white beam mirrors in synchrotron radiation beamlines.« less

The epidemiology of fractures in infants--Which accidents are preventable?

PubMed

Wegmann, Helmut; Orendi, Ingrid; Singer, Georg; Eberl, Robert; Castellani, Christoph; Schalamon, Johannes; Till, Holger

2016-01-01

In children, fractures have a huge impact on the health care system. In order to develop effective prevention strategies exact knowledge about the epidemiology of fractures is mandatory. This study aims to describe clinical and epidemiological data of fractures diagnosed in infants. A retrospective analysis of all infants (children<1 year of age) presenting with fractures in an 11 years period (2001-2011) was performed. Information was obtained regarding the location of the fractures, sites of the accident, circumstances and mechanisms of injury and post-injury care. 248 infants (54% male, 46% female) with a mean age of 7 months presented with 253 fractures. In more than half of the cases skull fractures were diagnosed (n=151, 61%). Most frequently the accidents causing fractures happened at home (67%). Falls from the changing table, from the arm of the care-giver and out of bed were most commonly encountered (n=92, 37%). While the majority of skull fractures was caused from falls out of different heights, external impacts tended to lead to fractures of the extremities. 6 patients (2%) were victims of maltreatment and sustained 10 fractures (2 skull fractures, 4 proximal humeral fractures, 2 rib fractures, and 2 tibial fractures). Falls from the changing table, the arms of the caregivers and out of bed caused the majority of fractures (especially skull fracture) in infants. Therefore, awareness campaigns and prevention strategies should focus on these mechanisms of accident in order to decrease the rate of fractures in infants. Copyright © 2015 Elsevier Ltd. All rights reserved.

A morphological and morphometric study of proximal and distal ends of dry radii with its clinical implications.

PubMed

Gupta, Chandni; Kalthur, Sneha Guruprasad; Malsawmzuali, J C; D'souza, Antony Sylvan

2015-01-01

Knowledge of the size and shape of radial head is essential for construction of radial head prosthesis. Further, the measurements of bicipital tuberosity and its angular relationship to radial head are significant in surgical techniques, like in the reconstruction of biceps tendon. Even the morphometry of the distal radius is significant in numerous clinical orthopedic situations such as reduction of distal radius fractures and in the design of distal radius prosthesis. So, the aim of the study was to determine the morphometric parameters of proximal and distal radius in dry adult Indian radius. Fifty intact adult Indian radius (right = 23, left = 27) were chosen, and the various parameters of proximal and distal ends of radius were studied. Student's t-test was done to correlate all these parameters on the right and left sides. The mean length of radius, height of head at medial and lateral ends, head anteroposterior and transverse diameter, head thickness at ventral, dorsal, and lateral ends were 23.5, 0.90, 0.75, 1.91, 1.85, 0.42, 0.32, and 0.30 cm, respectively. The mean depth of articular facet, length of neck, proximal and distal neck diameter, width and length of bicipital tuberosity, and radial circumference at bicipital tuberosity were 0.19, 1.19, 1.36, 1.31, 1.23, 1.97, and 4.54 cm, respectively. The mean length of styloid process, oblique and transverse width of lower end, anteroposterior diameter of lower end, and angle of radial inclination were 0.98cm, 2. 81cm, 2.59cm, 1.86cm, and 25.05°, respectively. This study will be useful for orthopedic surgeons in making prosthesis for the proximal and distal ends of radius.

Modelling DC responses of 3D complex fracture networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beskardes, Gungor Didem; Weiss, Chester Joseph

Here, the determination of the geometrical properties of fractures plays a critical role in many engineering problems to assess the current hydrological and mechanical states of geological media and to predict their future states. However, numerical modeling of geoelectrical responses in realistic fractured media has been challenging due to the explosive computational cost imposed by the explicit discretizations of fractures at multiple length scales, which often brings about a tradeoff between computational efficiency and geologic realism. Here, we use the hierarchical finite element method to model electrostatic response of realistically complex 3D conductive fracture networks with minimal computational cost.

Modelling DC responses of 3D complex fracture networks

DOE PAGES

Beskardes, Gungor Didem; Weiss, Chester Joseph

2018-03-01

Here, the determination of the geometrical properties of fractures plays a critical role in many engineering problems to assess the current hydrological and mechanical states of geological media and to predict their future states. However, numerical modeling of geoelectrical responses in realistic fractured media has been challenging due to the explosive computational cost imposed by the explicit discretizations of fractures at multiple length scales, which often brings about a tradeoff between computational efficiency and geologic realism. Here, we use the hierarchical finite element method to model electrostatic response of realistically complex 3D conductive fracture networks with minimal computational cost.

Principles of management of thoracolumbar fractures.

PubMed

Dai, Li-yang

2012-05-01

There is little consensus on treatment of thoracolumbar fractures, which are one of the most controversial areas in spine surgery. The great variations in clinical decision making may come from differences in evaluation of spine stability with these fractures. Few high-quality studies concerning optimal treatment of thoracolumbar fractures have been conducted. This article reviews the conflicting results and recommendations for management of thoracolumbar fractures of currently published reports. Specifically, it addresses issues regarding evaluation of stability, indications for operative treatment, timing of surgery, surgical approach, and fusion length. © 2012 Tianjin Hospital and Blackwell Publishing Asia Pty Ltd.

Can insertion length for a double-lumen endobronchial tube be predicted?

PubMed

Dyer, R A; Heijke, S A; Russell, W J; Bloch, M B; James, M F

2000-12-01

It has been suggested that the appropriate length of insertion for double-lumen tubes can be estimated by external measurement. This study examined the accuracy of external measurement in estimating the actual length of insertion required in 130 patients. It also examined the relationship between the length inserted and the patient's height in 126 patients and their weight in 125 patients. Although there was a fair correlation between the measured external length and the final inserted length (r = 0.61), the 95% confidence intervals of slope and intercept allowed a large variation and the prediction was too wide to be clinically useful. Height was reasonably well correlated with the final length (r = 0.51) but an equally wide 95% confidence interval rendered it of little clinical value. There was no correlation between weight and final tube length. It is concluded that external measurement alone is not adequate to predict a clinically acceptable position of the double-lumen tube.

Effects of footwear and stride length on metatarsal strains and failure in running.

PubMed

Firminger, Colin R; Fung, Anita; Loundagin, Lindsay L; Edwards, W Brent

2017-11-01

The metatarsal bones of the foot are particularly susceptible to stress fracture owing to the high strains they experience during the stance phase of running. Shoe cushioning and stride length reduction represent two potential interventions to decrease metatarsal strain and thus stress fracture risk. Fourteen male recreational runners ran overground at a 5-km pace while motion capture and plantar pressure data were collected during four experimental conditions: traditional shoe at preferred and 90% preferred stride length, and minimalist shoe at preferred and 90% preferred stride length. Combined musculoskeletal - finite element modeling based on motion analysis and computed tomography data were used to quantify metatarsal strains and the probability of failure was determined using stress-life predictions. No significant interactions between footwear and stride length were observed. Running in minimalist shoes increased strains for all metatarsals by 28.7% (SD 6.4%; p<0.001) and probability of failure for metatarsals 2-4 by 17.3% (SD 14.3%; p≤0.005). Running at 90% preferred stride length decreased strains for metatarsal 4 by 4.2% (SD 2.0%; p≤0.007), and no differences in probability of failure were observed. Significant increases in metatarsal strains and the probability of failure were observed for recreational runners acutely transitioning to minimalist shoes. Running with a 10% reduction in stride length did not appear to be a beneficial technique for reducing the risk of metatarsal stress fracture, however the increased number of loading cycles for a given distance was not detrimental either. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Relationship Between Constraint and Ductile Fracture Initiation as Defined by Micromechanical Analyses

NASA Technical Reports Server (NTRS)

Panontin, Tina L.; Sheppard, Sheri D.

1994-01-01

The use of small laboratory specimens to predict the integrity of large, complex structures relies on the validity of single parameter fracture mechanics. Unfortunately, the constraint loss associated with large scale yielding, whether in a laboratory specimen because of its small size or in a structure because it contains shallow flaws loaded in tension, can cause the breakdown of classical fracture mechanics and the loss of transferability of critical, global fracture parameters. Although the issue of constraint loss can be eliminated by testing actual structural configurations, such an approach can be prohibitively costly. Hence, a methodology that can correct global fracture parameters for constraint effects is desirable. This research uses micromechanical analyses to define the relationship between global, ductile fracture initiation parameters and constraint in two specimen geometries (SECT and SECB with varying a/w ratios) and one structural geometry (circumferentially cracked pipe). Two local fracture criteria corresponding to ductile fracture micromechanisms are evaluated: a constraint-modified, critical strain criterion for void coalescence proposed by Hancock and Cowling and a critical void ratio criterion for void growth based on the Rice and Tracey model. Crack initiation is assumed to occur when the critical value in each case is reached over some critical length. The primary material of interest is A516-70, a high-hardening pressure vessel steel sensitive to constraint; however, a low-hardening structural steel that is less sensitive to constraint is also being studied. Critical values of local fracture parameters are obtained by numerical analysis and experimental testing of circumferentially notched tensile specimens of varying constraint (e.g., notch radius). These parameters are then used in conjunction with large strain, large deformation, two- and three-dimensional finite element analyses of the geometries listed above to predict crack initiation loads and to calculate the associated (critical) global fracture parameters. The loads are verified experimentally, and microscopy is used to measure pre-crack length, crack tip opening displacement (CTOD), and the amount of stable crack growth. Results for A516-70 steel indicate that the constraint-modified, critical strain criterion with a critical length approximately equal to the grain size (0.0025 inch) provides accurate predictions of crack initiation. The critical void growth criterion is shown to considerably underpredict crack initiation loads with the same critical length. The relationship between the critical value of the J-integral for ductile crack initiation and crack depth for SECT and SECB specimens has been determined using the constraint-modified, critical strain criterion, demonstrating that this micromechanical model can be used to correct in-plane constraint effects due to crack depth and bending vs. tension loading. Finally, the relationship developed for the SECT specimens is used to predict the behavior of circumferentially cracked pipe specimens.

Numerical and Statistical Analysis of Fractures in Mechanically Dissimilar Rocks of Limestone Interbedded with Shale from Nash Point in Bristol Channel, South Wales, UK.

NASA Astrophysics Data System (ADS)

Adeoye-Akinde, K.; Gudmundsson, A.

2017-12-01

Heterogeneity and anisotropy, especially with layered strata within the same reservoir, makes the geometry and permeability of an in-situ fracture network challenging to forecast. This study looks at outcrops analogous to reservoir rocks for a better understanding of in-situ fracture networks and permeability, especially fracture formation, propagation, and arrest/deflection. Here, fracture geometry (e.g. length and aperture) from interbedded limestone and shale is combined with statistical and numerical modelling (using the Finite Element Method) to better forecast fracture network properties and permeability. The main aim is to bridge the gap between fracture data obtained at the core level (cm-scale) and at the seismic level (km-scale). Analysis has been made of geometric properties of over 250 fractures from the blue Lias in Nash Point, UK. As fractures propagate, energy is required to keep them going, and according to the laws of thermodynamics, this energy can be linked to entropy. As fractures grow, entropy increases, therefore, the result shows a strong linear correlation between entropy and the scaling exponent of fracture length and aperture-size distributions. Modelling is used to numerically simulate the stress/fracture behaviour in mechanically dissimilar rocks. Results show that the maximum principal compressive stress orientation changes in the host rock as the fracture-induced stress tip moves towards a more compliant (shale) layer. This behaviour can be related to the three mechanisms of fracture arrest/deflection at an interface, namely: elastic mismatch, stress barrier and Cook-Gordon debonding. Tensile stress concentrates at the contact between the stratigraphic layers, ahead of and around the propagating fracture. However, as shale stiffens with time, the stresses concentrated at the contact start to dissipate into it. This can happen in nature through diagenesis, and with greater depth of burial. This study also investigates how induced fractures propagate and interact with existing discontinuities in layered rocks using analogue modelling. Further work will introduce the Maximum Entropy Method for more accurate statistical modelling. This method is mainly useful to forecast likely fracture-size probability distributions from incomplete subsurface information.

Changing the surgical dogma in frontal sinus trauma: transnasal endoscopic repair.

PubMed

Grayson, Jessica W; Jeyarajan, Hari; Illing, Elisa A; Cho, Do-Yeon; Riley, Kristen O; Woodworth, Bradford A

2017-05-01

Management of frontal sinus trauma includes coronal or direct open approaches through skin incisions to either ablate or obliterate the frontal sinus for posterior table fractures and openly reduce/internally fixate fractured anterior tables. The objective of this prospective case-series study was to evaluate outcomes of frontal sinus anterior and posterior table trauma using endoscopic techniques. Prospective evaluation of patients undergoing surgery for frontal sinus fractures was performed. Data were collected regarding demographics, etiology, technique, operative site, length involving the posterior table, size of skull base defects, complications, and clinical follow-up. Forty-six patients (average age, 42 years) with frontal sinus fractures were treated using endoscopic techniques from 2008 to 2016. Mean follow-up was 26 (range, 0.5 to 79) months. Patients were treated primarily with a Draf IIb frontal sinusotomies. Draf III was used in 8 patients. Average fracture defect (length vs width) was 17.1 × 9.1 mm, and the average length involving the posterior table was 13.1 mm. Skull base defects were covered with either nasoseptal flaps or free tissue grafts. One individual required Draf IIb revision, but all sinuses were patent on final examination and all closed reductions of anterior table defects resulted in cosmetically acceptable outcomes. Frontal sinus trauma has traditionally been treated using open approaches. Our findings show that endoscopic management should become part of the management algorithm for frontal sinus trauma, which challenges current surgical dogma regarding mandatory open approaches. © 2017 ARS-AAOA, LLC.

Patterns of Growth after Kidney Transplantation among Children with ESRD

PubMed Central

Franke, Doris; Thomas, Lena; Steffens, Rena; Pavičić, Leo; Gellermann, Jutta; Froede, Kerstin; Querfeld, Uwe; Haffner, Dieter

2015-01-01

Background and objectives Poor linear growth is a frequent complication of CKD. This study evaluated the effect of kidney transplantation on age-related growth of linear body segments in pediatric renal transplant recipients who were enrolled from May 1998 until August 2013 in the CKD Growth and Development observational cohort study. Design, setting, participants, & measurements Linear growth (height, sitting height, arm and leg lengths) was prospectively investigated during 1639 annual visits in a cohort of 389 pediatric renal transplant recipients ages 2–18 years with a median follow-up of 3.4 years (interquartile range, 1.9–5.9 years). Linear mixed-effects models were used to assess age-related changes and predictors of linear body segments. Results During early childhood, patients showed lower mean SD scores (SDS) for height (−1.7) and a markedly elevated sitting height index (ratio of sitting height to total body height) compared with healthy children (1.6 SDS), indicating disproportionate stunting (each P<0.001). After early childhood a sustained increase in standardized leg length and a constant decrease in standardized sitting height were noted (each P<0.001), resulting in significant catch-up growth and almost complete normalization of sitting height index by adult age (0.4 SDS; P<0.01 versus age 2–4 years). Time after transplantation, congenital renal disease, bone maturation, steroid exposure, degree of metabolic acidosis and anemia, intrauterine growth restriction, and parental height were significant predictors of linear body dimensions and body proportions (each P<0.05). Conclusions Children with ESRD present with disproportionate stunting. In pediatric renal transplant recipients, a sustained increase in standardized leg length and total body height is observed from preschool until adult age, resulting in restoration of body proportions in most patients. Reduction of steroid exposure and optimal metabolic control before and after transplantation are promising measures to further improve growth outcome. PMID:25352379

Patterns of growth after kidney transplantation among children with ESRD.

PubMed

Franke, Doris; Thomas, Lena; Steffens, Rena; Pavičić, Leo; Gellermann, Jutta; Froede, Kerstin; Querfeld, Uwe; Haffner, Dieter; Živičnjak, Miroslav

2015-01-07

Poor linear growth is a frequent complication of CKD. This study evaluated the effect of kidney transplantation on age-related growth of linear body segments in pediatric renal transplant recipients who were enrolled from May 1998 until August 2013 in the CKD Growth and Development observational cohort study. Linear growth (height, sitting height, arm and leg lengths) was prospectively investigated during 1639 annual visits in a cohort of 389 pediatric renal transplant recipients ages 2-18 years with a median follow-up of 3.4 years (interquartile range, 1.9-5.9 years). Linear mixed-effects models were used to assess age-related changes and predictors of linear body segments. During early childhood, patients showed lower mean SD scores (SDS) for height (-1.7) and a markedly elevated sitting height index (ratio of sitting height to total body height) compared with healthy children (1.6 SDS), indicating disproportionate stunting (each P<0.001). After early childhood a sustained increase in standardized leg length and a constant decrease in standardized sitting height were noted (each P<0.001), resulting in significant catch-up growth and almost complete normalization of sitting height index by adult age (0.4 SDS; P<0.01 versus age 2-4 years). Time after transplantation, congenital renal disease, bone maturation, steroid exposure, degree of metabolic acidosis and anemia, intrauterine growth restriction, and parental height were significant predictors of linear body dimensions and body proportions (each P<0.05). Children with ESRD present with disproportionate stunting. In pediatric renal transplant recipients, a sustained increase in standardized leg length and total body height is observed from preschool until adult age, resulting in restoration of body proportions in most patients. Reduction of steroid exposure and optimal metabolic control before and after transplantation are promising measures to further improve growth outcome. Copyright © 2015 by the American Society of Nephrology.

Dietary Intake and Stress Fractures Among Elite Male Combat Recruits

DTIC Science & Technology

2012-03-13

groups that can be analyzed for nutrient and food group intake, such as: 1) eggs, milk , and milk products; 2) fats (including sauces); 3) chicken...intake of proteins , carbohydrates, total fat , iron, folate, vitamins (D, B6, and B12), calcium, zinc, and magnesium. Our study referred to the MDRI and...included body weight, height, body fat percentage and calculation of body mass index (BMI). Height (cm) was measured using a stadiometer (±1cm) and

Gear Crack Propagation Path Studies: Guidelines for Ultra-Safe Design

NASA Technical Reports Server (NTRS)

Lewicki, David G.

2001-01-01

Design guidelines have been established to prevent catastrophic rim fracture failure modes when considering gear tooth bending fatigue. Analysis was performed using the finite element method with principles of linear elastic fracture mechanics. Crack propagation paths were predicted for a variety of gear tooth and rim configurations. The effects of rim and web thicknesses, initial crack locations, and gear tooth geometry factors such as diametral pitch, number of teeth, pitch radius, and tooth pressure angle were considered. Design maps of tooth/rim fracture modes including effects of gear geometry, applied load, crack size, and material properties were developed. The occurrence of rim fractures significantly increased as the backup ratio (rim thickness divided by tooth height) decreased. The occurrence of rim fractures also increased as the initial crack location was moved down the root of the tooth. Increased rim and web compliance increased the occurrence of rim fractures. For gears with constant pitch radii, coarser-pitch teeth increased the occurrence of tooth fractures over rim fractures. Also, 25 deg pressure angle teeth had an increased occurrence of tooth fractures over rim fractures when compared to 20 deg pressure angle teeth. For gears with constant number of teeth or gears with constant diametral pitch, varying size had little or no effect on crack propagation paths.

Accuracy of Jump-Mat Systems for Measuring Jump Height.

PubMed

Pueo, Basilio; Lipinska, Patrycja; Jiménez-Olmedo, José M; Zmijewski, Piotr; Hopkins, Will G

2017-08-01

Vertical-jump tests are commonly used to evaluate lower-limb power of athletes and nonathletes. Several types of equipment are available for this purpose. To compare the error of measurement of 2 jump-mat systems (Chronojump-Boscosystem and Globus Ergo Tester) with that of a motion-capture system as a criterion and to determine the modifying effect of foot length on jump height. Thirty-one young adult men alternated 4 countermovement jumps with 4 squat jumps. Mean jump height and standard deviations representing technical error of measurement arising from each device and variability arising from the subjects themselves were estimated with a novel mixed model and evaluated via standardization and magnitude-based inference. The jump-mat systems produced nearly identical measures of jump height (differences in means and in technical errors of measurement ≤1 mm). Countermovement and squat-jump height were both 13.6 cm higher with motion capture (90% confidence limits ±0.3 cm), but this very large difference was reduced to small unclear differences when adjusted to a foot length of zero. Variability in countermovement and squat-jump height arising from the subjects was small (1.1 and 1.5 cm, respectively, 90% confidence limits ±0.3 cm); technical error of motion capture was similar in magnitude (1.7 and 1.6 cm, ±0.3 and ±0.4 cm), and that of the jump mats was similar or smaller (1.2 and 0.3 cm, ±0.5 and ±0.9 cm). The jump-mat systems provide trustworthy measurements for monitoring changes in jump height. Foot length can explain the substantially higher jump height observed with motion capture.

Posterior internal fixation plus vertebral bone implantation under navigational aid for thoracolumbar fracture treatment

PubMed Central

ZHOU, WEI; KONG, WEIQING; ZHAO, BIZHEN; FU, YISHAN; ZHANG, TAO; XU, JIANGUANG

2013-01-01

The aim of this study was to investigate the method of posterior thoracolumbar vertebral pedicle screw reduction and fixation combined with vertebral bone implantation via the affected vertebral body under navigational aid for the treatment of thoracolumbar fractures. The efficacy of the procedure was also measured. Between June 2005 and March 2011, posterior thoracolumbar vertebral pedicle screw reduction and fixation plus artificial bone implantation via the affected vertebral pedicle under navigational aid was used to treat 30 patients with thoracolumbar fractures, including 18 males and 12 females, ranging in age from 21 to 57 years. Compared with the values prior to surgery, intraspinal occupation, vertebral height ratio and Cobb angle at the follow-up were significantly improved. At the long-term follow-up, the postoperative Cobb angle loss was <1° and the anterior vertebral body height loss was <2 mm. Posterior thoracolumbar vertebral pedicle screw reduction and fixation combined with vertebral bone implantation via the affected vertebral body under navigational aid may increase the accuracy and safety of surgery, and it is an ideal method of internal implantation. Bone implantation via the affected vertebral body may increase vertebral stability. PMID:23935737

A case report: pregnancy-induced severe osteoporosis with eight vertebral fractures.

PubMed

Ofluoglu, Onder; Ofluoglu, Demet

2008-12-01

Osteoporosis associated with pregnancy and lactation is a rare condition. The prevalence, etiology and its pathogenesis is unknown. It causes one or more vertebral fractures with severe, prolonged back pain and height loss in affected women. Majority of the cases are seen in the third trimester or just after delivery in primagravid women. In this case report, a 30-year-old woman who had severe pregnancy-induced osteoporosis with 8 vertebral fractures was presented. During last month of her first pregnancy she had moderate back pain. After delivery, the back pain has gotten worse. The radiological examinations have shown that there was 50% in T6, T8 and T10; 30% in L2; 20% in L1 height loss and biconcave vertebral images in L3-5. In the bone mineral density, L2-4 T score was -4.7 and total femoral T score was -3.1. There was no abnormality in the laboratory findings except mild elevation in alkaline phosphates. Although pregnancy-associated osteoporosis is a rare condition, when pain occurs in the last trimester or early postpartum period, it should be considered in differential diagnosis.

Variation of facial features among three African populations: Body height match analyses.

PubMed

Taura, M G; Adamu, L H; Gudaji, A

2017-01-01

Body height is one of the variables that show a correlation with facial craniometry. Here we seek to discriminate the three populations (Nigerians, Ugandans and Kenyans) using facial craniometry based on different categories of body height of adult males. A total of 513 individuals comprising 234 Nigerians, 169 Ugandans and 110 Kenyans with mean age of 25.27, s=5.13 (18-40 years) participated. Paired and unpaired facial features were measured using direct craniometry. Multivariate and stepwise discriminate function analyses were used for differentiation of the three populations. The result showed significant overall facial differences among the three populations in all the body height categories. Skull height, total facial height, outer canthal distance, exophthalmometry, right ear width and nasal length were significantly different among the three different populations irrespective of body height categories. Other variables were sensitive to body height. Stepwise discriminant function analyses included maximum of six variables for better discrimination between the three populations. The single best discriminator of the groups was total facial height, however, for body height >1.70m the single best discriminator was nasal length. Most of the variables were better used with function 1, hence, better discrimination than function 2. In conclusion, adult body height in addition to other factors such as age, sex, and ethnicity should be considered in making decision on facial craniometry. However, not all the facial linear dimensions were sensitive to body height. Copyright © 2016 Elsevier GmbH. All rights reserved.

Analysis of Mode II Crack in Bilayered Composite Beam

NASA Astrophysics Data System (ADS)

Rizov, Victor I.; Mladensky, Angel S.

2012-06-01

Mode II crack problem in cantilever bilayered composite beams is considered. Two configurations are analyzed. In the first configuration the crack arms have equal heights while in the second one the arms have different heights. The modulus of elasticity and the shear modulus of the beam un-cracked part in the former case and the moment of inertia in the latter are derived as functions of the two layers characteristics. The expressions for the strain energy release rate, G are obtained on the basis of the simple beam theory according to the hypotheses of linear elastic fracture mechanics. The validity of these expressions is established by comparison with a known solution. Parametrical investigations for the influence of the moduli of elasticity ratio as well as the moments of inertia ratio on the strain energy release rate are also performed. The present article is a part of comprehensive investigation in Fracture mechanics of composite beams.

FracPaQ: A MATLAB™ toolbox for the quantification of fracture patterns

NASA Astrophysics Data System (ADS)

Healy, David; Rizzo, Roberto E.; Cornwell, David G.; Farrell, Natalie J. C.; Watkins, Hannah; Timms, Nick E.; Gomez-Rivas, Enrique; Smith, Michael

2017-02-01

The patterns of fractures in deformed rocks are rarely uniform or random. Fracture orientations, sizes, and spatial distributions often exhibit some kind of order. In detail, relationships may exist among the different fracture attributes, e.g. small fractures dominated by one orientation, larger fractures by another. These relationships are important because the mechanical (e.g. strength, anisotropy) and transport (e.g. fluids, heat) properties of rock depend on these fracture attributes and patterns. This paper describes FracPaQ, a new open source, cross-platform toolbox to quantify fracture patterns, including distributions in fracture attributes and their spatial variation. Software has been developed to quantify fracture patterns from 2-D digital images, such as thin section micrographs, geological maps, outcrop or aerial photographs or satellite images. The toolbox comprises a suite of MATLAB™ scripts based on previously published quantitative methods for the analysis of fracture attributes: orientations, lengths, intensity, density and connectivity. An estimate of permeability in 2-D is made using a parallel plate model. The software provides an objective and consistent methodology for quantifying fracture patterns and their variations in 2-D across a wide range of length scales, rock types and tectonic settings. The implemented methods presented are inherently scale independent, and a key task where applicable is analysing and integrating quantitative fracture pattern data from micro-to macro-scales. The toolbox was developed in MATLAB™ and the source code is publicly available on GitHub™ and the Mathworks™ FileExchange. The code runs on any computer with MATLAB installed, including PCs with Microsoft Windows, Apple Macs with Mac OS X, and machines running different flavours of Linux. The application, source code and sample input files are available in open repositories in the hope that other developers and researchers will optimise and extend the functionality for the benefit of the wider community.

Cyclic fatigue resistance of RaCe and Mtwo rotary files in continuous rotation and reciprocating motion.

PubMed

Vadhana, Sekar; SaravanaKarthikeyan, Balasubramanian; Nandini, Suresh; Velmurugan, Natanasabapathy

2014-07-01

The purpose of this study was to evaluate and compare the cyclic fatigue resistance of RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland) and Mtwo (VDW, Munich, Germany) rotary files in continuous rotation and reciprocating motion. A total of 60 new rotary Mtwo and RaCe files (ISO size = 25, taper = 0.06, length = 25 mm) were selected and randomly divided into 4 groups (n = 15 each): Mtc (Mtwo NiTi files in continuous rotation), Rc (RaCe NiTi files in continuous rotation), Mtr (Mtwo NiTi files in reciprocating motion), and Rr (RaCe NiTi files in reciprocating motion). A cyclic fatigue testing device was fabricated with a 60° angle of curvature and a 5-mm radius. All instruments were rotated or reciprocated until fracture occurred. The time taken for each instrument to fracture and the length of the broken fragments were recorded. All the fractured files were analyzed under a scanning electron microscope to detect the mode of fracture. The Kolmogorov-Smirnov test was used to assess the normality of samples distribution, and statistical analysis was performed using the independent sample t test. The time taken for the instruments of the Mtr and Rr groups to fail under cyclic loading was significantly longer compared with the Mtc and Rc groups (P < .001). Scanning electron microscopic observations showed that the instruments of all groups had undergone a ductile mode of fracture. The length of the fractured segments was between 5 and 6 mm, which was not statistically significant among the experimental groups. Mtwo and RaCe rotary instruments showed a significantly higher cyclic fatigue resistance in reciprocating motion compared with continuous rotation motion. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Micromechanics of shear localization in granular rocks - effect of temperature

NASA Astrophysics Data System (ADS)

Kanaya, T.; Hirth, G.

2017-12-01

We conducted detailed microscopy on porous sandstones deformed to varying axial strains in the low-temperature, brittle faulting regime and high-temperature, semibrittle faulting regime. This study is aimed to test the hypothsis that macroscopic faulting results from the interaction of distributed microfractures in granular rocks, and to assess how elevated temperature influences these shear loalization processes. We determined the ratio of fracture length vs. spacing for distributed microfractures (away from macroscopic faults) and compared it with fracture mechanics models of crack interaction. At low temperature, both tensile and shear microfractures obtain the critical geometry for crack-tip interaction. Both modes of microfractures occur at initial yielding and continue to lengthen with strain, in which many tensile microfractures propagate across grains. In contrast, at high temperature, only shear microfractures continue to lengthen with strain and reach the critical geometry; almost all tensile microfracutures arrest at grain boundaries. In addition, using the observed microfracture lengths and stresses, we determined the energy release rate (including interaction effects) for the longest shear microfractues characterized. These microfractures show length and stress consistent with Griffith criteria. At low temperature, shear fractures show energy release rate far greater than fracture energy, consistent with the observed dynamic failure. In contrast, at high temperature, shear microfractures show energy release rate similar to fracture energy, consistent with observed stable failire. Taken toghether, our resutls show that the linkage of shear microfracture is far more important for shear localization (macroscopic faulting) in granular rocks than in non-porous rocks. The interaction of both tentile and shear microfractures is important at low temperature, whereas that of teneile fracture is less improtant at high temperature. In addition, structure (desnity distirbution and orientation) of microfractures within the fault tip region is being investigated.

A Surgical Model of Posttraumatic Osteoarthritis With Histological and Gait Validation.

PubMed

Zahoor, Talal; Mitchell, Reed; Bhasin, Priya; Schon, Lew; Zhang, Zijun

2016-07-01

Posttraumatic osteoarthritis (PTOA) is secondary to an array of joint injuries. Animal models are useful tools for addressing the uniqueness of PTOA progression in each type of joint injury and developing strategies for PTOA prevention and treatment. Intra-articular fracture induces PTOA pathology. Descriptive laboratory study. Through a parapatellar incision, the medial tibial plateau was exposed in the left knees of 8 Sprague-Dawley rats. Osteotomy at the midpoint between the tibial crest and the outermost portion of the medial tibial plateau, including the covering articular cartilage, was performed using a surgical blade. The fractured medial tibial plateau was fixed with 2 needles transversely. The fractured knees were not immobilized. Before and after surgery, rat gait was recorded. Rats were sacrificed at week 8, and their knees were harvested for histology. After intra-articular fracture, the affected limbs altered gait from baseline (week 0). In the first 2 weeks, the gait of the operated limbs featured a reduced paw print intensity and stride length but increased maximal contact and stance time. Reduction of maximal and mean print area and duty cycle (the percentage of stance phase in a step) was present from week 1 to week 5. Only print length was reduced in weeks 7 and 8. At week 8, histology of the operated knees demonstrated osteoarthritic pathology. The severity of the PTOA pathology did not correlate with the changes of print length at week 8. Intra-articular fracture of the medial tibial plateau effectively induced PTOA in rat knees. During PTOA development, the injured limbs demonstrated characteristic gait. Intra-articular fracture represents severe joint injury and associates with a high rate of PTOA. This animal model, with histologic and gait validations, can be useful for future studies of PTOA prevention and early diagnosis.

Retrograde nailing for distal third femoral shaft fractures: a prospective study.

PubMed

Acharya, K N; Rao, M R

2006-12-01

To evaluate the postoperative knee function and results of unreamed retrograde nailing for distal third femoral shaft fractures. Between January 2002 and 2003 inclusive, a consecutive series of 27 patients (with 28 fractures) who underwent retrograde nailing were prospectively evaluated. Outcome measures were union time, initiation of weight bearing, deformity and shortening, functional length of the nail, knee function assessed using a modified Knee Society Knee Score. Correlations between union time and other variables were also studied. In these patients 26 (93%) of the 28 fractures achieved union, of which 5 underwent dynamisation; the mean union time for the other 21 fractures was 4.4 months. Angular malalignment was present in 4 patients and shortening in 4 others. There was negligible correlation between union time and variables of nail-canal diameter mismatch, functional length of nail, fracture geometry, or initiation of partial weight bearing ambulation. Knee flexion of more than 100 degrees was achieved in 26 patients. 19 patients had anterior knee pain and 10 had instability. By the end of one year, excellent or good scores for pain and function were recorded in 77% and 73% respectively, of the 26 patients. In view of such favourable union rates but significant deterioration in overall knee joint function, at best retrograde nailing is a reliable alternative in the management of selected complicated fractures of the distal femoral shaft.

Comparison of Radiofrequency-targeted Vertebral Augmentation With Balloon Kyphoplasty for the Treatment of Vertebral Compression Fractures: 2-Year Results.

PubMed

Bornemann, Rahel; Jansen, Tom R; Kabir, Koroush; Pennekamp, Peter H; Stüwe, Brit; Wirtz, Dieter C; Pflugmacher, Robert

2017-04-01

A retrospective study. The aim of this study was the evaluation of the safety and effectiveness of radiofrequency-targeted vertebral augmentation (RF-TVA) in comparison with balloon kyphoplasty (BK) for the treatment of acute painful vertebral compression fractures (VCFs) on the basis of matched pairs. Vertebroplasty and BK are the common surgical interventions for the treatment of VCF. Both are effective and safe but pose some risks such as adjacent fractures and cement leakage. In 2009, RF-TVA was introduced as an innovative augmentation procedure for the treatment of VCF. A total of 192 patients (116 female; 51-90 y) with VCF (n=303) at 1 to 3 levels were treated with RF-TVA or BK. Functionality (Oswestry Disability Index), pain (visual analogue scale), vertebral height (anterior, middle), and kyphotic angle were evaluated over a 2-year period (postoperatively, 3-4 d, 3, 6, 12, and 24 mo). In addition, operating time and occurrence of cement leakage were recorded. Pain and functionality were significantly improved after both treatments. In both groups, there was an increase in the vertebral height and a decrease in the kyphotic angle, which remained relatively consistent during 24 months. The incidence of cement leakage was 9.4% (n=9) in the RF-TVA group and 24.0% (n=25) in the BK group. The mean operating time with radiofrequency kyphoplasty was 25.9±9.9 minutes, and with balloon kyphoplasty 48.0±18.4 minutes. RF-TVA is a safe and effective procedure for the treatment of vertebral compression fractures when compared with BK. Improvement in pain and functional scores after RF-TVA are durable through 24 months postprocedure and remained better than those after BK at long-term follow-up. Operating time for RF-TVA is shorter and the risk of cement leakage is lower. Both procedures provided similar results in vertebral height restoration and reduction in the kyphotic angle.

Head Trauma-Related Deaths Among Preschool Children in Istanbul, Turkey.

PubMed

Yagmur, Fatih; Celik, Safa; Yener, Zeynep; Koral, Fatma; Yaman, Tuba; Sezer, Yigit; Kandemir, Eyup

2016-03-01

Head trauma takes place among the leading causes of mortality in children. This study aimed to determine the risk factors of head trauma-related deaths among children younger than 5 years in Istanbul, Turkey. This study was conducted using the records of the Morgue Department of the Council of Forensic Medicine in Istanbul. The records of cases autopsied between 2008 and 2012 were retrospectively investigated. Of all preschool children deaths, 203 head trauma-related deaths were included in the study. Of all, 117 (57.6%) were males and 86 (42.4%) were females. Most cases (107, 52.70%) were between the ages of 12 and 36 months. The most common mechanism of injury was "fall from a height" with 97 cases (47.78%), followed by "traffic accidents" (67, 33%) and "hit by falling objects" (19, 9.35%). Skull fracture was detected in 176 cases (86.69%), of which 81 (46.02%) were characterized with linear fracture. Furthermore, skull fracture was accompanied by 1 or more skeletal bone fracture in 64 cases. Retinal hemorrhage was investigated in 5 cases of suspected physical abuse and only 2 of them showed retinal hemorrhage findings. Obtained findings revealed that fall from a height was the leading cause of death among unnatural deaths in children younger than 5 years. Domestic accident was found to be a significant risk factor in childhood deaths. Traffic fatalities were among leading causes of death in childhood in our country, likewise in all around the world. Children were found to be more vulnerable to traumas when they start to move around with incomplete motor skills. Therefore, education of parents in terms of child supervision and installing safety precautions toward preschool children will be helpful in preventing such injuries. On the contrary to some findings in the literature, more severe lesions were also prominent even in case of short-range falls from a height.

Multi-scale modeling of microstructure dependent intergranular brittle fracture using a quantitative phase-field based method

DOE PAGES

Chakraborty, Pritam; Zhang, Yongfeng; Tonks, Michael R.

2015-12-07

In this study, the fracture behavior of brittle materials is strongly influenced by their underlying microstructure that needs explicit consideration for accurate prediction of fracture properties and the associated scatter. In this work, a hierarchical multi-scale approach is pursued to model microstructure sensitive brittle fracture. A quantitative phase-field based fracture model is utilized to capture the complex crack growth behavior in the microstructure and the related parameters are calibrated from lower length scale atomistic simulations instead of engineering scale experimental data. The workability of this approach is demonstrated by performing porosity dependent intergranular fracture simulations in UO 2 and comparingmore » the predictions with experiments.« less

Multi-scale modeling of microstructure dependent intergranular brittle fracture using a quantitative phase-field based method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, Pritam; Zhang, Yongfeng; Tonks, Michael R.

In this study, the fracture behavior of brittle materials is strongly influenced by their underlying microstructure that needs explicit consideration for accurate prediction of fracture properties and the associated scatter. In this work, a hierarchical multi-scale approach is pursued to model microstructure sensitive brittle fracture. A quantitative phase-field based fracture model is utilized to capture the complex crack growth behavior in the microstructure and the related parameters are calibrated from lower length scale atomistic simulations instead of engineering scale experimental data. The workability of this approach is demonstrated by performing porosity dependent intergranular fracture simulations in UO 2 and comparingmore » the predictions with experiments.« less

Hot and Steamy Fractures in the Philippines: The Geological Characterization and Permeability Evaluation of Fractures in the Southern Negros Geothermal Field, Philippines

NASA Astrophysics Data System (ADS)

Pastoriza, L. R.; Holdsworth, R.; McCaffrey, K. J. W.; Dempsey, E. D.; Walker, R. J.; Gluyas, J.; Reyes, J. K.

2016-12-01

Fluid flow pathway characterization is critical to geothermal exploration and exploitation. It requires a good understanding of the structural evolution, fault distribution and fluid flow properties. A dominantly fieldwork-based approach has been used to evaluate the potential fracture permeability characteristics of a typical high-temperature geothermal reservoir in the Southern Negros Geothermal Field, Philippines. This is a liquid-dominated geothermal resource hosted in the andesitic to dacitic Quaternary Cuernos de Negros Volcano in Negros Island. Fieldwork reveals two main fracture groups based on fault rock characteristics, alteration type, relative age of deformation, and associated thermal manifestation, with the younger fractures mainly related to the development of the modern geothermal system. Palaeostress analyses of cross-cutting fault and fracture arrays reveal a progressive counterclockwise rotation of stress axes from the (?)Pliocene up to the present-day, which is consistent with the regional tectonic models. A combined slip and dilation tendency analysis of the mapped faults indicates that NW-SE structures should be particularly promising drilling targets. Frequency versus length and aperture plots of fractures across six to eight orders of magnitude show power-law relationships with a change in scaling exponent in the region of 100 to 500m length-scales. Finally, evaluation of the topology of the fracture branches shows the dominance of Y-nodes that are mostly doubly connected suggesting good connectivity and permeability within the fracture networks. The results obtained in this study illustrate the value of methods that can be globally applied during exploration to better characterize fracture systems in geothermal reservoirs using multiscale datasets.

Hot and steamy fractures in the Philippines: the characterisation and permeability evaluation of fractures of the Southern Negros Geothermal Field, Negros Oriental, Philippines

NASA Astrophysics Data System (ADS)

Pastoriza, Loraine; Holdsworth, Robert; McCaffrey, Kenneth; Dempsey, Eddie; Walker, Richard; Gluyas, Jon; Reyes, Jonathan

2017-04-01

Fluid flow pathway characterisation is critical to geothermal exploration and exploitation. It requires a good understanding of the structural evolution, fault distribution and fluid flow properties. A dominantly fieldwork-based approach has been used to evaluate the potential fracture permeability characteristics of a typical high-temperature geothermal reservoir in the Southern Negros Geothermal Field, Philippines. This is a liquid-dominated geothermal resource hosted in the andesitic to dacitic Quaternary Cuernos de Negros Volcano in Negros Island. Fieldwork reveals two main fracture groups based on fault rock characteristics, alteration type, relative age of deformation, and associated thermal manifestation, with the younger fractures mainly related to the development of the modern geothermal system. Palaeostress analyses of cross-cutting fault and fracture arrays reveal a progressive counterclockwise rotation of stress axes from the (?)Pliocene up to the present-day, which is consistent with the regional tectonic models. A combined slip and dilation tendency analysis of the mapped faults indicates that NW-SE structures should be particularly promising drilling targets. Frequency versus length and aperture plots of fractures across six to eight orders of magnitude show power-law relationships with a change in scaling exponent in the region of 100 to 500m length-scales. Finally, evaluation of the topology of the fracture branches shows the dominance of Y-nodes that are mostly doubly connected suggesting good connectivity and permeability within the fracture networks. The results obtained in this study illustrate the value of methods that can be globally applied during exploration to better characterize fracture systems in geothermal reservoirs using multiscale datasets.

Radiographic Investigation of the Distal Extension of Fractures Into the Articular Surface of the Tibia (The RIDEFAST Study).

PubMed

Marchand, Lucas S; Rane, Ajinkya A; Working, Zachary M; Jacobson, Lance G; Kubiak, Erik N; Higgins, Thomas F; Rothberg, David L

2017-12-01

To determine whether radiographic measurements are predictive of involvement of the distal tibia articular surface in tibial shaft fractures. Retrospective review. Academic Level-I trauma hospital. Two-hundred seventeen patients with tibial shaft fractures distal to the isthmus (OTA/AO: 42-A1-3; 42-B1-3; 42-C1-3; and 43-A1-3). Analysis of anteroposterior (AP) and lateral radiographs. The following parameters were measured: (1) angle between the predominant fracture line and the plane of the tibial plafond (α-angle), (2) length of the shaft fracture, (3) distance from the most inferior extent of the shaft fracture to the tibial plafond (DTP), (4) width of the tibial plafond, (5) width of the tibial isthmus, (6) ratio of fracture length to DTP (FTP), and (7) fibular fracture distance. Distal intra-articular involvement (DIA). A total of 217 patients were identified, 56 (26%) with DIA. The FTP ratio as measured on both the AP (odds ratio: 8.20, confidence interval, 4.26-17.22, P < 0.0001) and lateral radiographs (10.00, 4.78-23.23, <0.0001) was the most effective screening measurement for DIA. AP and lateral FTP ratios of 0.224 and 0.255, respectively, achieved a negative predictive value of 100%, eliminating the need for computed tomography in 16%-23% of injuries. Involvement of the distal articular surface in patients with distal tibial shaft fractures is significantly associated with fracture geometry and pattern. The FTP ratio may be used as an effective screening tool to rule out of intra-articular involvement. Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Beyond-laboratory-scale prediction for channeling flows through subsurface rock fractures with heterogeneous aperture distributions revealed by laboratory evaluation

NASA Astrophysics Data System (ADS)

Ishibashi, Takuya; Watanabe, Noriaki; Hirano, Nobuo; Okamoto, Atsushi; Tsuchiya, Noriyoshi

2015-01-01

The present study evaluates aperture distributions and fluid flow characteristics for variously sized laboratory-scale granite fractures under confining stress. As a significant result of the laboratory investigation, the contact area in fracture plane was found to be virtually independent of scale. By combining this characteristic with the self-affine fractal nature of fracture surfaces, a novel method for predicting fracture aperture distributions beyond laboratory scale is developed. Validity of this method is revealed through reproduction of the results of laboratory investigation and the maximum aperture-fracture length relations, which are reported in the literature, for natural fractures. The present study finally predicts conceivable scale dependencies of fluid flows through joints (fractures without shear displacement) and faults (fractures with shear displacement). Both joint and fault aperture distributions are characterized by a scale-independent contact area, a scale-dependent geometric mean, and a scale-independent geometric standard deviation of aperture. The contact areas for joints and faults are approximately 60% and 40%. Changes in the geometric means of joint and fault apertures (µm), em, joint and em, fault, with fracture length (m), l, are approximated by em, joint = 1 × 102 l0.1 and em, fault = 1 × 103 l0.7, whereas the geometric standard deviations of both joint and fault apertures are approximately 3. Fluid flows through both joints and faults are characterized by formations of preferential flow paths (i.e., channeling flows) with scale-independent flow areas of approximately 10%, whereas the joint and fault permeabilities (m2), kjoint and kfault, are scale dependent and are approximated as kjoint = 1 × 10-12 l0.2 and kfault = 1 × 10-8 l1.1.

Gravidity, Parity and Vertebral Dimensions in the Northern Finland Birth Cohort 1966.

PubMed

Oura, Petteri; Paananen, Markus; Auvinen, Juha; Niinimäki, Jaakko; Niinimäki, Maarit; Karppinen, Jaro; Junno, Juho-Antti

2018-03-15

A population-based birth cohort study. To investigate the association between gravidity, parity and vertebral geometry among middle-aged women. Vertebral size is a recognized determinant of vertebral fracture risk. Yet only a few lifestyle factors that influence vertebral size are known. Pregnancy is a labile period which may affect the maternal vertebral size or shape. The lumbar lordosis angle is permanently deepened by pregnancy, but it remains unclear whether vertebral shape or size contribute to this deepened angle. We aimed to investigate whether gravidity and parity were associated with vertebral cross-sectional area (CSA) and height ratio (anterior height: posterior height) among 705 middle-aged women from the Northern Finland Birth Cohort 1966. We measured the corpus of their fourth lumbar vertebra using magnetic resonance imaging of the lumbar spine at the age of 46. Gravidity and parity were elicited using a questionnaire also at the age of 46. Linear regression analysis was used with adjustments for body mass index, vertebral CSA (height ratio models), and vertebral height (CSA models). We also ran a subgroup analysis which did not include nulliparous women, and we compared nulliparous women with grand multiparous women. The models found no statistically significant associations between the predictors and outcomes. Crude and adjusted results were highly similar, and the subgroup analyses provided analogous results. Pregnancy, or even multiple pregnancies, do not seem to have long-term effects on vertebral geometry. In order to enhance the prevention of vertebral fractures, future studies should aim to reveal more lifestyle determinants of vertebral size. 3.

Halovest treatment in traumatic cervical spine injury.

PubMed

Razak, M; Basir, T; Hyzan, Y; Johari, Z

1998-09-01

This is a cross-sectional study on the use of halovest appliance in the Orthopaedic and Traumatology Department, Kuala Lumpur Hospital from June 1993 to September 1996. Fifty-three patients with cervical spine injuries were treated by halovest stabilization. Majority of cases was caused by motor-vehicle accident; others were fall from height at construction sites, fall at home, hit by falling object and assault. The injuries were Jefferson fracture of C1, odontoid fractures, hangman fractures, open spinous process fracture and fracture body of C2, and fracture, and fracture-dislocation of the lower cervical spines. Majority of patients had hospital stay less than 30 days. The use of the halovest ranges from 4 to 16 weeks and the healing rate was 96%. Two patients of lower cervical spine injury had redislocation and one of them was operated. There was one case of non-union of type II odontoid fracture and treated by posterior fusion. Other complications encountered during halovest treatment were minor. They were pin-site infection, pin-loosening, clamp loosening and neck pain or neck stiffness. This method of treatment enables patient to ambulate early and reduces hospital stay. We found that halovest is easy to apply, safe and tolerable to most of the patients.

The impact analysis of the connecting pipe length and diameter on the operation of a piston hybrid power machine of positive displacement with gas suction capacity

NASA Astrophysics Data System (ADS)

Shcherba, V. E.; Grigoriev, A. V.; Averyanov, G. S.; Surikov, V. I.; Vedruchenko, V. P.; Galdin, N. S.; Trukhanova, D. A.

2017-08-01

The article analyzes the impact of the connecting liquid pipe length and diameter on consumables and power characteristics of the piston hybrid power machine with gas suction capacity. The following operating characteristics of the machine were constructed and analyzed: the average height of the liquid column in the jacket space; instantaneous velocity and height of the liquid column in the jacket space; the relative height of the liquid column in the jacket space; volumetric efficiency; indicator isothermal efficiency; flowrate in the pump section; relative pressure losses during suction; relative flowrate. The dependence of the instantaneous pressure in the work space and the suction space of the compressor section on the rotation angle of the crankshaft is determined for different values of the length and diameter of the connecting pipeline.

Work-related symptoms and checkstand configuration: an experimental study.

PubMed

Harber, P; Bloswick, D; Luo, J; Beck, J; Greer, D; Peña, L F

1993-07-01

Supermarket checkers are known to be at risk of upper-extremity cumulative trauma disorders. Forty-two experienced checkers checked a standard "market basket" of items on an experimental checkstand. The counter height could be adjusted (high = 35.5, low = 31.5 inches), and the pre-scan queuing area length (between conveyor belt and laser scanner) could be set to "near" or "far" lengths. Each subject scanned under the high-near, high-far, low-near, and low-far conditions in random order. Seven ordinal symptom scales were used to describe comfort. Analysis showed that both counter height and queuing length had significant effects on symptoms. Furthermore, the height of the subject affected the degree and direction of the impact of the checkstand configuration differences. The study suggests that optimization of design may be experimentally evaluated, that modification of postural as well as frequency loading may be beneficial, and that adjustability for the individual may be advisable.

Effect of leg length inequality on body weight distribution during walking with load: A pilot study

NASA Astrophysics Data System (ADS)

Zabri, S. W. K. Ali; Basaruddin, K. S.; Salleh, A. F.; Rusli, W. M. R.; Daud, R.

2017-09-01

This paper presents a pilot study on the effect of leg length inequality (LLI) on the body weight distribution. Plywood block was used to mimic the artificial LLI. The height of the plywood was increased up to 4.0 cm with 0.5 cm increment. Hence, eight different height of LLI was considered in order to investigate which height of LLI initiated the significant effect. The experiment was conducted on a healthy subject that walking on the force plate in two conditions; with a load of 2 kg (carried by a backpack worn by the subject) and without load. Qualisys Track Manager (QTM) system was employed for data processing. The results showed that the short leg subjected to more weight compared to the long leg during walking with inequality of leg length especially when carrying additional load.

Probabilistic finite elements for fracture mechanics

NASA Technical Reports Server (NTRS)

Besterfield, Glen

1988-01-01

The probabilistic finite element method (PFEM) is developed for probabilistic fracture mechanics (PFM). A finite element which has the near crack-tip singular strain embedded in the element is used. Probabilistic distributions, such as expectation, covariance and correlation stress intensity factors, are calculated for random load, random material and random crack length. The method is computationally quite efficient and can be expected to determine the probability of fracture or reliability.

Impact Damage and Erosion of Ceramics and Composites.

DTIC Science & Technology

1980-12-31

local fracture toughness, Keff’ with crack length, a, was used to determine the fracture criticality. Specifically, the fracture toughness was chosen...A complete description of strength behaviors thus requires an experimental determination of the local toughness, One of us (A. V. Virkar) is currently...34Simulated Strength - Grain Size Study Using Glass- Glass Ceramic Composite System," submitted to Journal of Materials Science, (1979). -~_ 6 I ~ -_- 0

Cold heavy oil production and production by radio-frequency electromagnetic radiation: Comparative numerical study

NASA Astrophysics Data System (ADS)

Davletbaev, Alfred; Kireev, Victor; Kovaleva, Liana; Zainullin, Aleksey; Minnigalimov, Rais

2016-12-01

Comparative analysis for "cold" heavy oil production from fractured well in low-permeability formation, as well as heavy oil production by radio-frequency electromagnetic heating has been carried out. The results of mathematical modeling for both these technologies taking into account different fracture's lengths show that the thermal method is most effective for more "short" fractures up to some their optimal size 5-10 m.

Comparison of cyclic fatigue resistance and bending properties of two reciprocating nickel-titanium glide path files.

PubMed

Özyürek, T; Uslu, G; Gündoğar, M; Yılmaz, K; Grande, N M; Plotino, G

2018-02-25

To compare the cyclic fatigue resistance and bending properties of R-Pilot and WaveOne Gold (WOG) Glider files, at intracanal temperature (35°C). Forty R-Pilot and 40 WOG Glider files were subjected to a cyclic fatigue resistance test (n = 20), calculating the time to fracture (TTF) in an artificial stainless steel canal. The length of the fractured file tips (FL) was also measured. The fracture surface of fragments was examined with a scanning electron microscope, and the cross-sectional area of the fractured surfaces was measured. Flexibility of the tested files (n = 20) was determined using 45° bending test. Data were analysed statistically using the Mann-Whitney U-test at 5% significance level. Time to fracture was significantly higher in the R-Pilot group compared to the WOG Glider (P < 0.05). There was no significant difference between groups for fracture length. The bending resistance of R-Pilot files was significantly greater than WOG Glider files (P < 0.05). A significant greater cyclic fatigue resistance was observed for R-Pilot files compared to WOG Glider instruments, although the bending resistance of WOG Glider files was lower. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.

An Effective Modal Approach to the Dynamic Evaluation of Fracture Toughness of Quasi-Brittle Materials

NASA Astrophysics Data System (ADS)

Ferreira, L. E. T.; Vareda, L. V.; Hanai, J. B.; Sousa, J. L. A. O.; Silva, A. I.

2017-05-01

A modal dynamic analysis is used as the tool to evaluate the fracture toughness of concrete from the results of notched-through beam tests. The dimensionless functions describing the relation between the frequencies and specimen geometry used for identifying the variation in the natural frequency as a function of crack depth is first determined for a 150 × 150 × 500-mm notched-through specimen. The frequency decrease resulting from the propagating crack is modeled through a modal/fracture mechanics approach, leading to determination of an effective crack length. This length, obtained numerically, is used to evaluate the fracture toughness of concrete, the critical crack mouth opening displacements, and the brittleness index proposed. The methodology is applied to tests performed on high-strength concrete specimens. The frequency response for each specimen is evaluated before and after each crack propagation step. The methodology is then validated by comparison with results from the application of other methodologies described in the literature and suggested by RILEM.

Fracture toughness determination using spiral-grooved cylindrical specimen and pure torsional loading

DOEpatents

Wang, Jy-An; Liu, Kenneth C.

2003-07-08

A method for determining fracture toughness K.sub.IC of materials ranging from metallic alloys, brittle ceramics and their composites, and weldments. A cylindrical specimen having a helical V-groove with a 45.degree. pitch is subjected to pure torsion. This loading configuration creates a uniform tensile-stress crack-opening mode, and a transverse plane-strain state along the helical groove. The full length of the spiral groove is equivalent to the thickness of a conventional compact-type specimen. K.sub.IC values are determined from the fracture torque and crack length measured from the test specimen using a 3-D finite element program (TOR3D-KIC) developed for the purpose. In addition, a mixed mode (combined tensile and shear stress mode) fracture toughness value can be determined by varying the pitch of the helical groove. Since the key information needed for determining the K.sub.IC value is condensed in the vicinity of the crack tip, the specimen can be significantly miniaturized without the loss of generality.

Dispersion in Fractures with Ramified Dissolution Patterns

NASA Astrophysics Data System (ADS)

Xu, Le; Marks, Benjy; Toussaint, Renaud; Flekkøy, Eirik G.; Måløy, Knut J.

2018-04-01

The injection of a reactive fluid into an open fracture may modify the fracture surface locally and create a ramified structure around the injection point. This structure will have a significant impact on the dispersion of the injected fluid due to increased permeability, which will introduce large velocity fluctuations into the fluid. Here, we have injected a fluorescent tracer fluid into a transparent artificial fracture with such a ramified structure. The transparency of the model makes it possible to follow the detailed dispersion of the tracer concentration. The experiments have been compared to two dimensional (2D) computer simulations which include both convective motion and molecular diffusion. A comparison was also performed between the dispersion from an initially ramified dissolution structure and the dispersion from an initially circular region. A significant difference was seen both at small and large length scales. At large length scales, the persistence of the anisotropy of the concentration distribution far from the ramified structure is discussed with reference to some theoretical considerations and comparison with simulations.

Characterization of Human Rib Biomechanical Responses due to Three-Point Bending.

PubMed

Kalra, Anil; Saif, Tal; Shen, Ming; Jin, Xin; Zhu, Feng; Begeman, Paul; Yang, King H; Millis, Scott

2015-11-01

In the elderly population, rib fracture is one of the most common injuries sustained in motor vehicle crashes. The current study was conducted to predict the biomechanical fracture responses of ribs with respect to age, gender, height, weight and percentage of ash content. Three-point bending experiments were conducted on 278 isolated rib samples extracted from 82 cadaver specimens (53 males and 29 females between the ages of 21 and 87 years) for 6th and 7th levels of ribs. Statistical analyses were carried out to identify differences based on age and gender. It was found that, in comparison to males, females had significantly lower values for maximum bending moments, slopes of bending moment-angle curves, and average cortical-bone thickness (p<0.05). Samples of ribs taken from elderly specimens failed at lower values of fracture moments than those from younger specimens, and had lower slopes of bending moment-angle curves, both in males and females (p<0.05). The generalized estimated equations were developed to predict the values of biomechanical response and average cortical thickness based on age, gender, height and weight of individual specimens. Results from the current study illustrate that biomechanical responses and rib cortical thicknesses are functions of age, gender, height and weight. However, the current study is limited to a quasi-static loading scheme, which is different from real crash conditions. Hence, rib-material properties, which are dependent on strain rate, and are needed for wholebody finite element models representing different populations, still require more research.

A Climatology of Fair-Weather Cloud Statistics at the Atmospheric Radiation Measurement Program Southern Great Plains Site: Temporal and Spatial Variability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berg, Larry K.; Kassianov, Evgueni I.; Long, Charles N.

2006-03-30

In previous work, Berg and Stull (2005) developed a new parameterization for Fair-Weather Cumuli (FWC). Preliminary testing of the new scheme used data collected during a field experiment conducted during the summer of 1996. This campaign included a few research flights conducted over three locations within the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site. A more comprehensive verification of the new scheme requires a detailed climatology of FWC. Several cloud climatologies have been completed for the ACRF SGP, but these efforts have focused on either broad categories of clouds grouped by height and seasonmore » (e.g., Lazarus et al. 1999) or height and time of day (e.g., Dong et al. 2005). In these two examples, the low clouds were not separated by the type of cloud, either stratiform or cumuliform, nor were the horizontal chord length (the length of the cloud slice that passed directly overhead) or cloud aspect ratio (defined as the ratio of the cloud thickness to the cloud chord length) reported. Lane et al. (2002) presented distributions of cloud chord length, but only for one year. The work presented here addresses these shortcomings by looking explicitly at cases with FWC over five summers. Specifically, we will address the following questions: •Does the cloud fraction (CF), cloud-base height (CBH), and cloud-top height (CTH) of FWC change with the time of day or the year? •What is the distribution of FWC chord lengths? •Is there a relationship between the cloud chord length and the cloud thickness?« less

Predictors for perioperative blood transfusion in elderly patients with extra capsular hip fractures treated with cephalo-medullary nailing.

PubMed

Fazal, M Ali; Bagley, Caroline; Garg, Parag

2018-02-01

The aim of our study was to determine predictive factors and requirement for perioperative blood transfusion in elderly patients with extra capsular hip fractures treated with cephalo-medullary device. Seventy-nine patients with extra capsular hip fractures treated with cephalo-medullary nailing were included in the study. Age, sex, ASA grade, timing of surgery, preoperative and postoperative haemoglobin, length of hospital stay, fracture type, number of units transfused and 30-day mortality were recorded. The mean age was 82.3 years. Forty-seven patients underwent a short nail and 32 patients a long nail; 53.4% patients required blood transfusion postoperatively. Transfusion was required in 71.8% of the long nails (p < 0.05), 65.8% patients above the age of 80 (p < 0.05), 100% of the patients with hemoglobin below 90 g/L and 20 patients with a ASA grade of 3 (p < 0.05). 78.5% patients with A2 fracture and 75% of A3 fractures needed blood transfusion (p > 0.05). Length of hospital stay in non-transfusion group was 13 days and in transfusion group was 19 days (p < 0.05). 55.1% operated within 36 h and 47.6% operated after 36 h of admission needed transfusion (p > 0.05). Thirty-day mortality in patients needing blood transfusion was 5% and in non-transfusion group was 3.7% (p > 0.05). Patient age, ASA grade, preoperative haemoglobin and length of nail are reliable predictors for perioperative blood transfusion in extra capsular hip fractures in elderly patients treated with cephalo-medullary nailing and reinforce a selective transfusion policy. Copyright © 2017 Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. Production and hosting by Elsevier B.V. All rights reserved.

Accuracy of vertical height measurements on direct digital panoramic radiographs using posterior mandibular implants and metal balls as reference objects.

PubMed

Vazquez, L; Nizamaldin, Y; Combescure, C; Nedir, R; Bischof, M; Dohan Ehrenfest, D M; Carrel, J-P; Belser, U C

2013-01-01

Conventional panoramic radiography, a widely used radiographic examination tool in implant treatment planning, allows evaluation of the available bone height before inserting posterior mandibular implants. Image distortion and vertical magnification due to projection geometry is well described for rotational panoramic radiographs. To assess the accuracy of vertical height measurements on direct digital panoramic radiographs, implants and metal balls positioned in the posterior mandible were used as radio-opaque reference objects. The reproducibility of the measuring method was assessed by the inter- and intraobserver agreements. Direct digital panoramic radiographs, performed using a Kodak 8000C (Eastman Kodak Company, Rochester, NY), of 17 partially edentulous patients (10 females, 7 males, mean age 65 years) were selected from an X-ray database gathered during routine clinical evaluation of implant sites. Proprietary software and a mouse-driven calliper were used to measure the radiological length of 25 implants and 18 metal reference balls, positioned in mandibular posterior segments. The distortion ratio (DR) was calculated by dividing the radiological implant length by the implant's real length and the radiological ball height by the ball's real height. Mean vertical DR was 0.99 for implants and 0.97 for balls, and was unrelated to mandibular sites, side, age, gender or observer. Inter- and intraobserver agreements were acceptable for both reference objects. Vertical measurements had acceptable accuracy and reproducibility when a software-based calibrated measurement tool was used, confirming that digital panoramic radiography can be reliably utilized to determine the pre-operative implant length in premolar and molar mandibular segments.

Personal Equipment and Clothing Correction Factors for the Australian Army: A Pilot Survey

DTIC Science & Technology

2014-11-01

Sitting M24 Fit Thigh Clearance M12 Clearance and Fit, DHM Knee Height, Sitting M13 Fit, DHM Popliteal Height M14 Fit, DHM Buttock-Knee Length...Measure Semi-Nude Definition Encumbered Definition EM28 Knee Height, Sitting Footrest surface to Suprapatella ( M13 ). Footrest surface to

[Case-control study on T-shaped locking internal fixation and external fixation for the treatment of dorsal Barton's fracture].

PubMed

Chen, Huan-qing; Wen, Xi-le; Li, Yang-ming; Wen, Cong-you

2015-06-01

To compare clinical effect of T-shaped locking internal fixation and external fixation in treating dorsal Barton's fracture,and investigate selective strategy of internal fixation. From January 2008 to January 2013, 100 patients with dorsal Barton's fracture were randomly divided into two groups. In treatment group, there were 30 males and 20 females with an average age of (33.8±3.6) years old;30 cases were type B, 20 cases were type C;and treated with T-shaped locking internal fixation. In control group, there were 32 male and 18 females with an average age of (32.9±3.4) years old; 29 cases were type B, 21 cases were type C; and treated with external fixation. Volar tilt, ulnar deviation and radial height at 3 months after operation were detected and compared between two groups. Mechara functional evaluation were used to evaluate postoperative clinical effects. Clinical cure time, postoperative complications,joint mobility and function score were recorded and compared between two groups. In treatment group,volar tilt was (11.9±2.7)°, ulnar deviation was (20.8+ 2.9)°,and radial height was (10.9±1.8) mm; while volar tilt was (9.1±1.6)°, ulnar deviation was (17.1±2.9)°, and radial height was (8.1±1.5) mm in control group. Treatment group was better than control group in volar tilt, ulnar deviation and radial height. Clinical cure time in treatment group was(12.0±2.3) weeks, shorter than control group (18.0±4.1) weeks. The incidence of complications in treatment group was lower than control group. According to Mehara functional evaluation,20 cases got excellent results, 25 good, 3 moderate and 2 poor in treatment group; 16 cases got excellent results, 14 good, 10 moderate and 10 poor in control group. Treatment group was better than control group in clinical effects. T-shaped locking internal fixation with postoperative functional exercise for the treatment of dorsal Barton's fracture fits for biomechanics demands,and has advantages of stable fixation,rapid recovery, less complications and good functional recovery, it has better clinical effects.

Scala tympani measurement.

PubMed

Walby, A P

1985-01-01

The length and cross-sectional height of the scala tympani are relevant to the design of cochlear implants. The lengths and heights of the scalae tympani in ten pairs of serially sectioned temporal bones were measured by an adaptation of the serial section method of cochlear reconstruction. The study found the middle segments of individual pairs of scalae tympani to be very similar in height, but each pair varied slightly from other pairs. The height decreased overall from the base to the apex, but there was a small expansion at the junction of the basal and middle turns where the interscalar septum originated. The theoretical relationships of different diameter electrodes to the organ of Corti were plotted for one cochlea. The size of the electrode and the path it followed were shown in theory to alter considerably its position in relation to the organ of Corti.

Ultrasonic probing of the fracture process zone in rock using surface waves

NASA Technical Reports Server (NTRS)

Swanson, P. L.; Spetzler, H.

1984-01-01

A microcrack process zone is frequently suggested to accompany macrofractures in rock and play an important role in the resistance to fracture propagation. Attenuation of surface waves propagating through mode I fractures in wedge-loaded double-cantilever beam specimens of Westerly granite has been recorded in an attempt to characterize the structure of the fracture process zone. The ultrasonic measurements do not support the generally accepted model of a macroscopic fracture that incrementally propagates with the accompaniment of a cloud of microcracks. Instead, fractures in Westerly granite appear to form as gradually separating surfaces within a zone having a width of a few millimeters and a length of several tens of millimeters. A fracture process zone of this size would necessitate the use of meter-sized specimens in order for linear elastic fracture mechanics to be applicable.

Epidemiology of rib fractures in older men: Osteoporotic Fractures in Men (MrOS) prospective cohort study.

PubMed

Barrett-Connor, Elizabeth; Nielson, Carrie M; Orwoll, Eric; Bauer, Douglas C; Cauley, Jane A

2010-03-15

To study the causes and consequences of radiologically confirmed rib fractures (seldom considered in the context of osteoporosis) in community dwelling older men. Prospective cohort study (Osteoporotic Fractures in Men (MrOS) Study). 5995 men aged 65 or over recruited in 2000-2 from six US sites; 99% answered mailed questionnaires about falls and fractures every four months for a mean 6.2 (SD 1.3) year follow-up. New fractures validated by radiology reports; multivariate Cox proportional hazard ratios were used to evaluate factors independently associated with time to incident rib fracture; associations between baseline rib fracture and incident hip and wrist fracture were also evaluated. The incidence of rib fracture was 3.5/1000 person years, and 24% (126/522) of all incident non-spine fractures were rib fractures. Nearly half of new rib fractures (48%; n=61) followed falling from standing height or lower. Independent risk factors for an incident rib fracture were age 80 or above, low bone density, difficulty with instrumental activities of daily living, and a baseline history of rib/chest fracture. Men with a history of rib/chest fracture had at least a twofold increased risk of an incident rib fracture (adjusted hazard ratio 2.71, 95% confidence interval 1.86 to 3.95), hip fracture (2.05, 1.33 to 3.15), and wrist fracture (2.06, 1.14 to 3.70). Only 14/82 of men reported being treated with bone specific drugs after their incident rib fracture. Rib fracture, the most common incident clinical fracture in men, was associated with classic risk markers for osteoporosis, including old age, low hip bone mineral density, and history of fracture. A history of rib fracture predicted a more than twofold increased risk of future fracture of the rib, hip, or wrist, independent of bone density and other covariates. Rib fractures should be considered to be osteoporotic fractures in the evaluation of older men for treatment to prevent future fracture.

Reassessment of osteoporosis-related femoral fractures and economic burden in Saudi Arabia.

PubMed

Sadat-Ali, Mir; Al-Dakheel, Dakheel A; Azam, Md Q; Al-Bluwi, Mohammed T; Al-Farhan, Mohammed F; AlAmer, Hussein A; Al-Meer, Zakaria; Al-Mohimeed, Abdallah; Tabash, Ibrahim K; Karry, Maher O; Rassasy, Yaseen M; Baragaba, Mohammed A; Amer, Ahmed S; AlJawder, Abdallah; Al-Bouri, Kamil M; ElTinay, Mohammed; Badawi, Hamed A; Al-Othman, Abdallah A; Tayara, Badar K; Al-Faraidy, Moaad H; Amin, Ahmed H

2015-01-01

The current study reassesses the prevalence of fragility fractures and lifetime costs in the Eastern Province of Saudi Arabia. Forty-two percent (391) of the fractures were at the neck of the femur, and 38.6 % (354) were inter-trochanteric fractures. The overall incidence was assessed to be 7528 (1,300,336 population 55 years or older) with the direct cost of SR564.75 million ($150.60 million). A National Fracture Registry and osteoporosis awareness programs are recommended. Proximal femur fragility fractures are reported to be increasing worldwide due to increased life expectancy. The current study is carried out to assess the incidence of such fractures in the Eastern Province of Saudi Arabia and to assess the costs incurred in managing them annually. Finally, by extrapolating the data, the study can calculate the overall economic burden in Saudi Arabia. The data of fragility proximal femur fractures was collected from 24 of 28 hospitals in the Eastern Province. The data included age, sex, mode of injury, type of fracture, prescribed drug (and its cost), and length of hospital stay. Population statistics were obtained from the Department of Statistics of the Saudi Arabian government Web site. Twenty-four hospitals (85 %) participated in the study. A total of 780 fractures were sustained by 681 patients. Length of stay in the hospital averaged 23.28 ± 13.08 days. The projected fracture rate from all the hospitals would be 917 (an incidence of 5.81/1000), with a total cost of SR68.77 million. Further extrapolation showed that the overall incidence could be 7528 (1,300,336 population 55 years or older) with the direct cost of SR564.75 million ($150.60 million). Osteoporosis-related femoral fractures in Saudi Arabia are significant causes of morbidity besides incurring economic burden. We believe that a National Fracture Registry needs to be established, and osteoporosis awareness programs should be instituted in every part of Saudi Arabia so that these patients can be diagnosed early and treated appropriately to reduce both the number of fractures and the economic burden of the fractures.

Diagnostic accuracy of maternal anthropometric measurements as predictors for dystocia in nulliparous women

PubMed Central

Alijahan, Rahele; Kordi, Masoumeh; Poorjavad, Munira; Ebrahimzadeh, Saeed

2014-01-01

Background: Dystocia is one of the important causes of maternal morbidity and mortality in low-income countries. This study was aimed to determine the diagnostic accuracy of maternal anthropometric measurements as predictors for dystocia in nulliparous women. Materials and Methods: This prospective cohort study was conducted on 447 nulliparous women who referred to Omolbanin hospital. Several maternal anthropometric measurements such as height, transverse and vertical diameters of Michaelis sacral rhomboid area, foot length, head circumference, vertebral and lower limb length, symphysio-fundal height, and abdominal girth were taken in cervical dilatation ≤ 5 cm. Labor progression was controlled by a researcher blind to these measurements. After delivery, the accuracy of individual and combined measurements in prediction of dystocia was analyzed. Dystocia was defined as cesarean section and vacuum or forceps delivery for abnormal progress of labor (cervical dilatation less than 1 cm/h in the active phase for 2 h, and during the second stage, beyond 2 h or fetal head descend less than 1 cm/h). Results: Among the different anthropometric measurements, transverse diameter of the Michaelis sacral rhomboid area ≤9.6 cm, maternal height ≤ 155 cm, height to symphysio-fundal height ratio ≤4.7, lower limb length ≤78 cm, and head circumference to height ratio ≥ 35.05 with accuracy of 81.2%, 68.2%, 65.5%, 63.3%, and 61.5%, respectively, were better predictors. The best predictor was obtained by combination of maternal height ≤155 cm or the transverse diameter of the Michaelis sacral rhomboid area ≤9.6 cm and Johnson's formula estimated fetal weight ≥3255 g, with an accuracy of 90.5%, sensitivity of 70%, and specificity of 93.7%. Conclusions: Combination of other anthropometric measurements and estimated fetal weight with maternal height in comparison to maternal height alone leads to a better predictor for dystocia. PMID:24554954

Diagnostic accuracy of maternal anthropometric measurements as predictors for dystocia in nulliparous women.

PubMed

Alijahan, Rahele; Kordi, Masoumeh; Poorjavad, Munira; Ebrahimzadeh, Saeed

2014-01-01

Dystocia is one of the important causes of maternal morbidity and mortality in low-income countries. This study was aimed to determine the diagnostic accuracy of maternal anthropometric measurements as predictors for dystocia in nulliparous women. This prospective cohort study was conducted on 447 nulliparous women who referred to Omolbanin hospital. Several maternal anthropometric measurements such as height, transverse and vertical diameters of Michaelis sacral rhomboid area, foot length, head circumference, vertebral and lower limb length, symphysio-fundal height, and abdominal girth were taken in cervical dilatation ≤ 5 cm. Labor progression was controlled by a researcher blind to these measurements. After delivery, the accuracy of individual and combined measurements in prediction of dystocia was analyzed. Dystocia was defined as cesarean section and vacuum or forceps delivery for abnormal progress of labor (cervical dilatation less than 1 cm/h in the active phase for 2 h, and during the second stage, beyond 2 h or fetal head descend less than 1 cm/h). Among the different anthropometric measurements, transverse diameter of the Michaelis sacral rhomboid area ≤9.6 cm, maternal height ≤ 155 cm, height to symphysio-fundal height ratio ≤4.7, lower limb length ≤78 cm, and head circumference to height ratio ≥ 35.05 with accuracy of 81.2%, 68.2%, 65.5%, 63.3%, and 61.5%, respectively, were better predictors. The best predictor was obtained by combination of maternal height ≤155 cm or the transverse diameter of the Michaelis sacral rhomboid area ≤9.6 cm and Johnson's formula estimated fetal weight ≥3255 g, with an accuracy of 90.5%, sensitivity of 70%, and specificity of 93.7%. Combination of other anthropometric measurements and estimated fetal weight with maternal height in comparison to maternal height alone leads to a better predictor for dystocia.

Rock fracture skeleton tracing by image processing and quantitative analysis by geometry features

NASA Astrophysics Data System (ADS)

Liang, Yanjie

2016-06-01

In rock engineering, fracture measurement is important for many applications. This paper proposes a novel method for rock fracture skeleton tracing and analyzing. As for skeleton localizing, the curvilinear fractures are multiscale enhanced based on a Hessian matrix, after image binarization, and clutters are post-processed by image analysis; subsequently, the fracture skeleton is extracted via ridge detection combined with a distance transform and thinning algorithm, after which gap sewing and burrs removal repair the skeleton. In regard to skeleton analyzing, the roughness and distribution of a fracture network are respectively described by the fractal dimensions D s and D b; the intersection and fragmentation of a fracture network are respectively characterized by the average number of ends and junctions per fracture N average and the average length per fracture L average. Three rock fracture surfaces are analyzed for experiments and the results verify that both the fracture tracing accuracy and the analysis feasibility are satisfactory using the new method.

The Role of Interface Shape on the Impact Characteristics and Cranial Fracture Patterns Using the Immature Porcine Head Model,.

PubMed

Vaughan, Patrick E; Vogelsberg, Caitlin C M; Vollner, Jennifer M; Fenton, Todd W; Haut, Roger C

2016-09-01

The forensic literature suggests that when adolescents fall onto edged and pointed surfaces, depressed fractures can occur at low energy levels. This study documents impact biomechanics and fracture characteristics of infant porcine skulls dropped onto flat, curved, edged, and focal surfaces. Results showed that the energy needed for fracture initiation was nearly four times higher against a flat surface than against the other surfaces. While characteristic measures of fracture such as number and length of fractures did not vary with impact surface shape, the fracture patterns did depend on impact surface shape. While experimental impacts against the flat surface produced linear fractures initiating at sutural boundaries peripheral to the point of impact (POI), more focal impacts produced depressed fractures initiating at the POI. The study supported case-based forensic literature suggesting cranial fracture patterns depend on impact surface shape and that fracture initiation energy is lower for more focal impacts. © 2016 American Academy of Forensic Sciences.

Risk Factors for Osteoporosis and Fractures in Postmenopausal Women Between 50 and 65 Years of Age in a Primary Care Setting in Spain: A Questionnaire

PubMed Central

Luz Rentero, Maria; Carbonell, Cristina; Casillas, Marta; González Béjar, Milagros; Berenguer, Rafael

2008-01-01

Introduction Osteoporosis (OP) is a major, highly prevalent health problem and osteoporosis-related fractures account for high morbidity and mortality. Therefore, prevention and early detection of osteoporosis should strive to substantially reduce this risk of fracture. Objective The present observational, descriptive, cross-sectional study sought to assess the prevalence of risk factors for osteoporosis and fractures in a large sample of postmenopausal women aged 50 to 65 years attending Primary Care facilities in Spain. Methods We recruited 4,960 women, at 96 Primary Care centers. Demographic and anthropometrical data, as well as information regarding risk factors for OP were collected using a questionnaire. Results The prevalence rates for the major osteoporosis risk factors in our population were: low calcium intake, 43%; benzodiazepine use, 35.1%, and height loss, 30.1%. Other relatively prevalent factors include: having suffered at least one fall during the preceding year; positive family history of falls (particularly on the mother’s side), smoking, kyphosis, presence of any disease affecting bone metabolism, personal history of falls, and inability to rise from a chair without using one’s arms. The least frequent factors were weight loss of greater than 10% over the preceding 10 years and problems in sensory perception that affect patient’s ability to walk. Conclusions The main risk factors for osteoporosis in women 50-65 years of age are low calcium intake, use of benzodiazepines, and observed loss of height. Our results may help physicians to identify groups at risk for OP and fractures at early stages and consequently, optimize prevention and early diagnosis of osteoporosis in postmenopausal women. PMID:19088873

Acrylic kyphoplasty in recent nonosteoporotic fractures of the thoracolumbar junction: a prospective clinical and 3D radiologic study of 54 patients.

PubMed

Saget, Mathieu; Teyssedou, Simon; Prebet, Remi; Vendeuvre, Tanguy; Gayet, Louis-Etienne; Pries, Pierre

2014-08-01

Prospective clinical and radiological study. To evaluate the impact of stand-alone acrylic kyphoplasty in the treatment of recent traumatic fractures of the thoracolumbar spine in young patients. The management of fractures of the thoracolumbar spine without neurological deficit remains controversial. For a long time clinicians could only chose between functional treatment, orthopedic treatment, and traditional surgery. The recent advent of minimally invasive surgical techniques is an interesting alternative. Fifty-four patients with a mean age of 45.8±18.2 years and who had recently sustained a fracture of the thoracolumbar junction were enrolled into the study. Balloon kyphoplasty was performed using acrylic cement. Radiologic assessments (computed tomography scans) and clinical assessments (including Visual Analog Scale and Oswestry Disability Index scores) were used to determine kyphoplasty success and measure patient recovery over 2 years. Kyphoplasty reduced mean vertebral kyphosis from 12.8±5.0 degrees at trauma to 8.2±5.1 degrees at 2-year follow-up. Mean vertebral kyphosis was corrected by -5.7±4.7 degrees (P=0.0001) at the point of first verticalization, with no significant change at the 2-year follow-up visit (+1.1±4.3 degrees, P=0.1058). Kyphoplasty significantly augmented the height of the 6 anterior and intermediate segments. Maximum mean augmentation of intermediate vertebral height after 6 months was (11.6%±15.5%, P<0.0001). Patients tolerated the procedure well and 56% of them returned to work 3 months after kyphoplasty. Kyphoplasty is safe and effective in the correction of nonosteoporotic fractures of the thoracolumbar junction in young patients, and remains stable for at least 2 years postsurgery.

Heel-Rise Height Deficit 1 Year After Achilles Tendon Rupture Relates to Changes in Ankle Biomechanics 6 Years After Injury.

PubMed

Brorsson, Annelie; Willy, Richard W; Tranberg, Roy; Grävare Silbernagel, Karin

2017-11-01

It is unknown whether the height of a heel-rise performed in the single-leg standing heel-rise test 1 year after an Achilles tendon rupture (ATR) correlates with ankle biomechanics during walking, jogging, and jumping in the long-term. To explore the differences in ankle biomechanics, tendon length, calf muscle recovery, and patient-reported outcomes at a mean of 6 years after ATR between 2 groups that, at 1-year follow-up, had less than 15% versus greater than 30% differences in heel-rise height. Cohort study; Level of evidence, 3. Seventeen patients with less than 15% (<15% group) and 17 patients with greater than 30% (>30% group) side-to-side difference in heel-rise height at 1 year after ATR were evaluated at a mean (SD) 6.1 (2.0) years after their ATR. Ankle kinematics and kinetics were sampled via standard motion capture procedures during walking, jogging, and jumping. Patient-reported outcome was evaluated with Achilles tendon Total Rupture Score (ATRS), Physical Activity Scale (PAS), and Foot and Ankle Outcome Score (FAOS). Tendon length was evaluated by ultrasonography. The Limb Symmetry Index (LSI = [Injured Side ÷ Healthy Side] × 100) was calculated for side differences. The >30% group had significantly more deficits in ankle kinetics during all activities compared with patients in the <15% group at a mean of 6 years after ATR (LSI, 70%-149% and 84%-106%, respectively; P = .010-.024). The >30% group, compared with the <15% group, also had significantly lower values in heel-rise height (LSI, 72% and 95%, respectively; P < .001) and heel-rise work (LSI, 58% and 91%, respectively; P < .001) and significantly larger side-to-side difference in tendon length (114% and 106%, respectively; P = .012). Achilles tendon length correlated with ankle kinematic variables ( r = 0.38-0.44; P = .015-.027) whereas heel-rise work correlated with kinetic variables ( r = -0.57 to 0.56; P = .001-.047). LSI tendon length correlated negatively with LSI heel-rise height ( r = -0.41; P = .018). No differences were found between groups in patient-reported outcome ( P = .143-.852). Height obtained during the single-leg standing heel-rise test performed 1 year after ATR related to the long-term ability to regain normal ankle biomechanics. Minimizing tendon elongation and regaining heel-rise height may be important for the long-term recovery of ankle biomechanics, particularly during more demanding activities such as jumping.

Differences in childhood adiposity influence upper limb fracture site

PubMed Central

Moon, Rebecca J; Lim, Adelynn; Farmer, Megan; Segaran, Avinash; Clarke, Nicholas MP; Dennison, Elaine M; Harvey, Nicholas C; Cooper, Cyrus; Davies, Justin H

2015-01-01

Introduction Although it has been suggested that overweight and obese children have an increased risk of fracture, recent studies in post-menopausal women have shown that the relationship between obesity and fracture risk varies by fracture site. We therefore assessed whether adiposity and overweight/obesity prevalence differed by upper limb fracture site in children. Methods Height, weight, BMI, triceps and subscapular skinfold thickness (SFT) were measured in children aged 3-18 years with an acute upper limb fracture. Data was compared across three fracture sites (hand, forearm and upper arm/shoulder [UA]), and to published reference data. Results 401 children (67.1% male, median age 11.71 years (range 3.54-17.27 years) participated. 34.2%, 50.6% and 15.2% had fractures of the hand, forearm and UA, respectively. Children with forearm fractures had higher weight, BMI and SFT z-scores than those with UA fractures (p<0.05 for all). SFT z-scores were also higher in children with forearm fractures compared to hand fractures, but children withor hand and UA fractures did not differ. Overweight and obesity prevalence was higher in children with forearm fractures (37.6%) than those with UA fractures (19.0%, p=0.009). This prevalence was also higher than the published United Kingdom population prevalence (27.9%, p=0.003), whereas that of children with either UA (p=0.13) or hand fractures (29.1%, p=0.76) did not differ. The differences in anthropometry and overweight/obesity were similar for boys, but not present in girls. Conclusion Measurements of adiposity and the prevalence of overweight/obesity differ by fracture site in children, and in particular boys, with upper limb fractures. PMID:26027507

Nutritional risk and anthropometric evaluation in pediatric liver transplantation.

PubMed

Zamberlan, Patrícia; Leone, Cláudio; Tannuri, Uenis; Carvalho, Werther Brunow de; Delgado, Artur Figueiredo

2012-12-01

To analyze the nutritional status of pediatric patients after orthotopic liver transplantation and the relationship with short-term clinical outcome. Anthropometric evaluations of 60 children and adolescents after orthotopic liver transplantation, during the first 24 hours in a tertiary pediatric intensive care unit. Nutritional status was determined from the Z score for the following indices: weight/age height/age or length/age, weight/height or weight/length, body mass index/age, arm circumference/age and triceps skinfold/age. The severity of liver disease was evaluated using one of the two models which was adequated to the patients' age: 1. Pediatric End-stage Liver Disease, 2. Model for End-Stage Liver Disease. We found 50.0% undernutrition by height/age; 27.3% by weight/age; 11.1% by weight/height or weight/ length; 10.0% by body mass index/age; 61.6% by arm circumference/age and 51.0% by triceps skinfold/age. There was no correlation between nutritional status and Pediatric End-stage Liver Disease or mortality. We found a negative correlation between arm circumference/age and length of hospitalization. Children with chronic liver diseases experience a significant degree of undernutrition, which makes nutritional support an important aspect of therapy. Despite the difficulties in assessment, anthropometric evaluation of the upper limbs is useful to evaluate nutritional status of children before or after liver transplantation.

Evaluation of methods for calculating maximum allowable standing height in amputees competing in Paralympic athletics.

PubMed

Connick, M J; Beckman, E; Ibusuki, T; Malone, L; Tweedy, S M

2016-11-01

The International Paralympic Committee has a maximum allowable standing height (MASH) rule that limits stature to a pre-trauma estimation. The MASH rule reduces the probability that bilateral lower limb amputees use disproportionately long prostheses in competition. Although there are several methods for estimating stature, the validity of these methods has not been compared. To identify the most appropriate method for the MASH rule, this study aimed to compare the criterion validity of estimations resulting from the current method, the Contini method, and four Canda methods (Canda-1, Canda-2, Canda-3, and Canda-4). Stature, ulna length, demispan, sitting height, thigh length, upper arm length, and forearm length measurements in 31 males and 30 females were used to calculate the respective estimation for each method. Results showed that Canda-1 (based on four anthropometric variables) produced the smallest error and best fitted the data in males and females. The current method was associated with the largest error of those tests because it increasingly overestimated height in people with smaller stature. The results suggest that the set of Canda equations provide a more valid MASH estimation in people with a range of upper limb and bilateral lower limb amputations compared with the current method. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of triamcinolone in keloids morphological changes and cell apoptosis.

PubMed

dos Santos, João Márcio Prazeres; de Souza, Cláudio; de Vasconcelos, Anílton César; Nunes, Tarcizo Afonso

2015-06-01

to assess the effects of injectable triamcinolone on keloid scars length, height and thickness, and on the number of cells undergoing apoptosis. This study consists in a prospective, controlled, randomized, single-blinded clinical trial, conducted with fifteen patients with ear keloids divided into two groups: group 1 - seven patients undergoing keloid excisions, and group 2 - eight patients undergoing keloid excisions after three sessions of infiltration with one ml of Triamcinolone hexacetonide (20mg/ml) with three week intervals between them and between the last session and surgery. The two groups were homogeneous regarding age, gender and evolution of the keloid scar. The keloid scars of patients in group 2 were measured for the length, height and thickness before triamcinolone injection and before surgery. A blinded observer performed morphological detailing and quantification of cells in hematoxylin-eosin-stained surgical specimens. An apoptotic index was created. The apoptotic index in group 1 was 56.82, and in group 2, 68.55, showing no significant difference as for apoptosis (p=0.0971). The reduction in keloid dimensions in Group 2 was 10.12% in length (p=0.6598), 11.94% in height (p=0.4981) and 15.62% in thickness (p=0.4027). This study concluded that the infiltration of triamcinolone in keloid scars did not increase the number of apoptosit and did not reduce keloids' size, length, height or thickness.

Vertebroplasty and kyphoplasty: a systematic review of 69 clinical studies.

PubMed

Hulme, Paul A; Krebs, Jörg; Ferguson, Stephen J; Berlemann, Ulrich

2006-08-01

Systematic literature review. To evaluate the safety and efficacy of vertebroplasty and kyphoplasty using the data presented in published clinical studies, with respect to patient pain relief, restoration of mobility and vertebral body height, complication rate, and incidence of new adjacent vertebral fractures. Vertebroplasty and kyphoplasty have been gaining popularity for treating vertebral fractures. Current reviews provide an overview of the procedures but are not comprehensive and tend to rely heavily on personal experience. This article aimed to compile all available data and evaluate the clinical outcome of the 2 procedures. This is a systematic review of all the available data presented in peer-reviewed published clinical trials. The methodological quality of included studies was evaluated, and data were collected targeting specific standard measurements. Where possible, a quantitative aggregation of the data was performed. A large proportion of subjects had some pain relief, including 87% with vertebroplasty and 92% with kyphoplasty. Vertebral height restoration was possible using kyphoplasty (average 6.6 degrees ) and for a subset of patients using vertebroplasty (average 6.6 degrees ). Cement leaks occurred for 41% and 9% of treated vertebrae for vertebroplasty and kyphoplasty, respectively. New fractures of adjacent vertebrae occurred for both procedures at rates that are higher than the general osteoporotic population but approximately equivalent to the general osteoporotic population that had a previous vertebral fracture. The problem with stating definitely that vertebroplasty and kyphoplasty are safe and effective procedures is the lack of comparative, blinded, randomized clinical trials. Standardized evaluative methods should be adopted.

Dependence of displacement-length scaling relations for fractures and deformation bands on the volumetric changes across them

USGS Publications Warehouse

Schultz, R.A.; Soliva, R.; Fossen, H.; Okubo, C.H.; Reeves, D.M.

2008-01-01

Displacement-length data from faults, joints, veins, igneous dikes, shear deformation bands, and compaction bands define two groups. The first group, having a power-law scaling relation with a slope of n = 1 and therefore a linear dependence of maximum displacement and discontinuity length (Dmax = ??L), comprises faults and shear (non-compactional or non-dilational) deformation bands. These shearing-mode structures, having shearing strains that predominate over volumetric strains across them, grow under conditions of constant driving stress, with the magnitude of near-tip stress on the same order as the rock's yield strength in shear. The second group, having a power-law scaling relation with a slope of n = 0.5 and therefore a dependence of maximum displacement on the square root of discontinuity length (Dmax = ??L0.5), comprises joints, veins, igneous dikes, cataclastic deformation bands, and compaction bands. These opening- and closing-mode structures grow under conditions of constant fracture toughness, implying significant amplification of near-tip stress within a zone of small-scale yielding at the discontinuity tip. Volumetric changes accommodated by grain fragmentation, and thus control of propagation by the rock's fracture toughness, are associated with scaling of predominantly dilational and compactional structures with an exponent of n = 0.5. ?? 2008 Elsevier Ltd.

Composite Bone and Soft Tissue Loss Treated with Distraction Histiogenesis

DTIC Science & Technology

2010-01-01

their frames removed had healed docking sites, and the fourth whose frame remained in place had a healing fracture without evidence of delayed union ...interventions (3–8). The goals of limb salvage surgery in this setting are to restore length and alignment, regenerate bone loss, obtain fracture union ...angulation to manage composite bone and soft tissue loss associated with combat-related type IIIB open tibia fractures . Four patients underwent placement

The Shear Mechanisms of Natural Fractures during the Hydraulic Stimulation of Shale Gas Reservoirs.

PubMed

Zhang, Zhaobin; Li, Xiao

2016-08-23

The shearing of natural fractures is important in the permeability enhancement of shale gas reservoirs during hydraulic fracturing treatment. In this work, the shearing mechanisms of natural fractures are analyzed using a newly proposed numerical model based on the displacement discontinuities method. The fluid-rock coupling system of the model is carefully designed to calculate the shearing of fractures. Both a single fracture and a complex fracture network are used to investigate the shear mechanisms. The investigation based on a single fracture shows that the non-ignorable shearing length of a natural fracture could be formed before the natural fracture is filled by pressurized fluid. Therefore, for the hydraulic fracturing treatment of the naturally fractured shale gas reservoirs, the shear strength of shale is generally more important than the tensile strength. The fluid-rock coupling propagation processes of a complex fracture network are simulated under different crustal stress conditions and the results agree well with those of the single fracture. The propagation processes of complex fracture network show that a smaller crustal stress difference is unfavorable to the shearing of natural fractures, but is favorable to the formation of complex fracture network.

The Shear Mechanisms of Natural Fractures during the Hydraulic Stimulation of Shale Gas Reservoirs

PubMed Central

Zhang, Zhaobin; Li, Xiao

2016-01-01

The shearing of natural fractures is important in the permeability enhancement of shale gas reservoirs during hydraulic fracturing treatment. In this work, the shearing mechanisms of natural fractures are analyzed using a newly proposed numerical model based on the displacement discontinuities method. The fluid-rock coupling system of the model is carefully designed to calculate the shearing of fractures. Both a single fracture and a complex fracture network are used to investigate the shear mechanisms. The investigation based on a single fracture shows that the non-ignorable shearing length of a natural fracture could be formed before the natural fracture is filled by pressurized fluid. Therefore, for the hydraulic fracturing treatment of the naturally fractured shale gas reservoirs, the shear strength of shale is generally more important than the tensile strength. The fluid-rock coupling propagation processes of a complex fracture network are simulated under different crustal stress conditions and the results agree well with those of the single fracture. The propagation processes of complex fracture network show that a smaller crustal stress difference is unfavorable to the shearing of natural fractures, but is favorable to the formation of complex fracture network. PMID:28773834

Large-eddy simulations of surface roughness parameter sensitivity to canopy-structure characteristics

DOE PAGES

Maurer, K. D.; Bohrer, G.; Kenny, W. T.; ...

2015-04-30

Surface roughness parameters, namely the roughness length and displacement height, are an integral input used to model surface fluxes. However, most models assume these parameters to be a fixed property of plant functional type and disregard the governing structural heterogeneity and dynamics. In this study, we use large-eddy simulations to explore, in silico, the effects of canopy-structure characteristics on surface roughness parameters. We performed a virtual experiment to test the sensitivity of resolved surface roughness to four axes of canopy structure: (1) leaf area index, (2) the vertical profile of leaf density, (3) canopy height, and (4) canopy gap fraction.more » We found roughness parameters to be highly variable, but uncovered positive relationships between displacement height and maximum canopy height, aerodynamic canopy height and maximum canopy height and leaf area index, and eddy-penetration depth and gap fraction. We also found negative relationships between aerodynamic canopy height and gap fraction, as well as between eddy-penetration depth and maximum canopy height and leaf area index. We generalized our model results into a virtual "biometric" parameterization that relates roughness length and displacement height to canopy height, leaf area index, and gap fraction. Using a decade of wind and canopy-structure observations in a site in Michigan, we tested the effectiveness of our model-driven biometric parameterization approach in predicting the friction velocity over heterogeneous and disturbed canopies. We compared the accuracy of these predictions with the friction-velocity predictions obtained from the common simple approximation related to canopy height, the values calculated with large-eddy simulations of the explicit canopy structure as measured by airborne and ground-based lidar, two other parameterization approaches that utilize varying canopy-structure inputs, and the annual and decadal means of the surface roughness parameters at the site from meteorological observations. We found that the classical representation of constant roughness parameters (in space and time) as a fraction of canopy height performed relatively well. Nonetheless, of the approaches we tested, most of the empirical approaches that incorporate seasonal and interannual variation of roughness length and displacement height as a function of the dynamics of canopy structure produced more precise and less biased estimates for friction velocity than models with temporally invariable parameters.« less

Large-eddy simulations of surface roughness parameter sensitivity to canopy-structure characteristics

NASA Astrophysics Data System (ADS)

Maurer, K. D.; Bohrer, G.; Kenny, W. T.; Ivanov, V. Y.

2015-04-01

Surface roughness parameters, namely the roughness length and displacement height, are an integral input used to model surface fluxes. However, most models assume these parameters to be a fixed property of plant functional type and disregard the governing structural heterogeneity and dynamics. In this study, we use large-eddy simulations to explore, in silico, the effects of canopy-structure characteristics on surface roughness parameters. We performed a virtual experiment to test the sensitivity of resolved surface roughness to four axes of canopy structure: (1) leaf area index, (2) the vertical profile of leaf density, (3) canopy height, and (4) canopy gap fraction. We found roughness parameters to be highly variable, but uncovered positive relationships between displacement height and maximum canopy height, aerodynamic canopy height and maximum canopy height and leaf area index, and eddy-penetration depth and gap fraction. We also found negative relationships between aerodynamic canopy height and gap fraction, as well as between eddy-penetration depth and maximum canopy height and leaf area index. We generalized our model results into a virtual "biometric" parameterization that relates roughness length and displacement height to canopy height, leaf area index, and gap fraction. Using a decade of wind and canopy-structure observations in a site in Michigan, we tested the effectiveness of our model-driven biometric parameterization approach in predicting the friction velocity over heterogeneous and disturbed canopies. We compared the accuracy of these predictions with the friction-velocity predictions obtained from the common simple approximation related to canopy height, the values calculated with large-eddy simulations of the explicit canopy structure as measured by airborne and ground-based lidar, two other parameterization approaches that utilize varying canopy-structure inputs, and the annual and decadal means of the surface roughness parameters at the site from meteorological observations. We found that the classical representation of constant roughness parameters (in space and time) as a fraction of canopy height performed relatively well. Nonetheless, of the approaches we tested, most of the empirical approaches that incorporate seasonal and interannual variation of roughness length and displacement height as a function of the dynamics of canopy structure produced more precise and less biased estimates for friction velocity than models with temporally invariable parameters.

Minimizing Leg Length Discrepancy After Intramedullary Nailing of Comminuted Femoral Shaft Fractures: A Quality Improvement Initiative Using the Scout Computed Tomography Scanogram.

PubMed

Gheraibeh, Petra; Vaidya, Rahul; Hudson, Ian; Meehan, Robert; Tonnos, Frederick; Sethi, Anil

2018-05-01

To prevent leg length discrepancy (LLD) after locked femoral nailing in patients with comminuted femoral shaft fractures. Prospective consecutive case series aimed at quality improvement. Level 1 Trauma Center PATIENTS:: Ninety-eight consecutive patients with a comminuted femoral shaft fracture underwent statically locked intramedullary nailing, with a focused attempt at minimizing LLD during surgery. A computed tomography scanogram of both legs was performed on postoperative day 1 to assess for residual LLD. Patients were offered the option to have LLD >1.5 cm corrected before discharge. LLD >1.5 cm. Twenty-one patients (21.4%) were found to have an LLD >1.5 cm. An LLD >1.5 cm occurred in 10/55 (18%) antegrade nail patients and 11/43 (26%) retrograde nail patients (P = 0.27). No difference was noted based on the mechanism of injury, surgeon training and OTA/AO type B versus C injury. Ninety of 98 patients left with <1.5 cm LLD, 13/21 had a correction all to ≤0.6 cm, and 8 decided to accept the LLD and declined early correction. No patient left the hospital with an LLD >1.5 cm after locked intramedullary nailing for a comminuted femoral shaft fracture without being informed and the option of early correction. We recommend using a full-length computed tomography scanogram after IM nailing of comminuted femur fractures to prevent iatrogenic LLD. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Determinants of Costs and Length of Stay for Hip Fracture Patients

PubMed Central

Castelli, Adriana; Daidone, Silvio; Jacobs, Rowena; Kasteridis, Panagiotis; Street, Andrew David

2015-01-01

Background and Purpose An ageing population at greater risk of proximal femoral fracture places an additional clinical and financial burden on hospital and community medical services. We analyse the variation in i) length of stay (LoS) in hospital and ii) costs across the acute care pathway for hip fracture from emergency admission, to hospital stay and follow-up outpatient appointments. Patients and Methods We analyse patient-level data from England for 2009/10 for around 60,000 hip fracture cases in 152 hospitals using a random effects generalized linear multi-level model where the dependent variable is given by the patient’s cost or length of stay (LoS). We control for socio-economic characteristics, type of fracture and intervention, co-morbidities, discharge destination of patients, and quality indicators. We also control for provider and social care characteristics. Results Older patients and those from more deprived areas have higher costs and LoS, as do those with specific co-morbidities or that develop pressure ulcers, and those transferred between hospitals or readmitted within 28 days. Costs are also higher for those having a computed tomography (CT) scan or cemented arthroscopy. Costs and LoS are lower for those admitted via a 24h emergency department, receiving surgery on the same day of admission, and discharged to their own homes. Interpretation Patient and treatment characteristics are more important as determinants of cost and LoS than provider or social care factors. A better understanding of the impact of these characteristics can support providers to develop treatment strategies and pathways to better manage this patient population. PMID:26204450

Paediatric tibial shaft fractures treated by open reduction and stabilization with monolateral external fixation

PubMed Central

Simon, A.-L.; Apostolou, N.; Vidal, C.; Ferrero, E.; Mazda, K.; Ilharreborde, B.

2018-01-01

Abstract Purpose Elastic stable intramedullary nailing is increasingly used for surgical treatment of tibial shaft fractures, but frequently requires immobilization and delayed full weight-bearing. Therefore, external fixation remains interesting. The aim was to report clinico-radiological outcomes of monolateral external fixation for displaced and unstable tibial shaft fractures in children. Methods All tibial fractures consecutively treated by monolateral external fixation between 2008 and 2013 were followed. Inclusion criteria included skeletal immaturity and closed and open Gustilo I fractures caused by a direct impact. Patients were seen until two years postoperatively. Demographics, mechanism of injury, surgical data and complications were recorded. Anteroposterior and lateral side radiographs were performed at each visit. Full-limb 3D reconstructions using biplanar stereroradiography was performed for final limb length and alignment measures. Results A total of 45 patients (mean age 9.7 years ± 0.5) were included. In all, 17 were Gustilo I fractures, with no difference between open and closed fractures for any data. Mean time to full weight bearing was 18.2 days ± 0.7. After 15 days, 39 patients returned to school. Hardware removal (mean time to union 15.6 weeks ± 0.8) was performed during consultation under analgesic gas. There were no cases of nonunion. No fracture healed with > 10° of angulation (mean 5.1° ± 0.4°). Leg-length discrepancy > 10 mm was found for six patients. Conclusions This procedure can be a safe and simple surgical treatment for children with tibial shaft fractures. Few complications and early return to school were reported, with the limitations of non-comparative study. Level of Evidence IV PMID:29456750

Anatomical predisposition of the ankle joint for lateral sprain or lateral malleolar fracture evaluated by radiographic measurements.

PubMed

Lee, Kyoung Min; Chung, Chin Youb; Sung, Ki Hyuk; Lee, SeungYeol; Kim, Tae Gyun; Choi, Young; Jung, Ki Jin; Kim, Yeon Ho; Koo, Seung Bum; Park, Moon Seok

2015-01-01

Injury mechanism and the amount of force are important factors determining whether a fracture or sprain occurs at the time of an ankle inversion injury. However, the anatomical differences between the ankle fracture and sprain have not been investigated sufficiently. This study was performed to investigate whether an anatomical predisposition of the ankle joint results in a lateral malleolar fracture or lateral ankle sprain. Two groups of consecutive patients, one with lateral malleolar fracture (274 patients, mean age 49.0 years) and the other with lateral ankle sprain (400 patients, mean age 38.4 years), were evaluated. Ankle radiographs were examined for 7 measures: distal tibial articular surface (DTAS) angle, bimalleolar tilt (BT), medial malleolar relative length (MMRL), lateral malleolar relative length (LMRL), medial malleolar slip angle (MMSA), anterior inclination of tibia (AI), and fibular position (FP). After an interobserver reliability test, the radiographic measurements were compared between the 2 groups. Linear regression analysis was performed to correct for age and sex effects between the groups. The fracture group and the sprain group showed significant differences in BT (P = .001), MMSA (P < .001), AI (P = .023), and FP (P < .001). In multiple regression analysis, after adjusting for age and sex effects, fracture and sprain groups showed a significant difference in BT (P = .001), MMRL (P < .001), MMSA (P < .001), and FP (P < .001). The lateral malleolar fracture group tended to show more bony constraint than that of the lateral ankle sprain group. Further 3-dimensional assessment of the bony structure and subsequent biomechanical studies are needed to elucidate the mechanism of injury according to the various types of ankle fractures and ankle sprain. Level III, retrospective comparative study. © The Author(s) 2014.

Curriculum Theory, Curriculum Policy and the Problem of Ill-Disciplined Thinking

ERIC Educational Resources Information Center

Harris, Richard; Burn, Katharine

2011-01-01

This paper examines the implications of policy fracture and arms length governance within the decision-making processes currently shaping curriculum design within the English education system. In particular, it argues that an unresolved "ideological fracture" at the government level has been passed down to school leaders whose response…

Strain Rate Sensitivity of Polymer-Matrix Composites under Mode I delamination

DTIC Science & Technology

1990-12-01

unstable growth system requires two values. In reality , the fracture toughness may vary along the length of the specimen due to strain rate effects...18 M. F. Kanninen. An Augmented Double Cantilever Beam Model for Studying Crack Propagation and Arrest. International Journal of Fracture. Vol. 9

High weight or body mass index increase the risk of vertebral fractures in postmenopausal osteoporotic women.

PubMed

Pirro, Matteo; Fabbriciani, Gianluigi; Leli, Christian; Callarelli, Laura; Manfredelli, Maria Rosaria; Fioroni, Claudio; Mannarino, Massimo Raffaele; Scarponi, Anna Maria; Mannarino, Elmo

2010-01-01

In the general population, low body weight and body mass index (BMI) are significant risk factors for any fracture, but the specific association between body weight, BMI, and prevalence of vertebral fractures in osteoporotic women is not fully recognized. Hence, the association between body weight, BMI, and prevalent vertebral fractures was investigated in 362 women with never-treated postmenopausal osteoporosis. All participants underwent measurement of BMI, bone mineral density (BMD), and semiquantitative assessment of vertebral fractures. Thirty percent of participants had > or =1 vertebral fracture. Body weight and BMI were associated with L1-L4 BMD (R = 0.29, P < 0.001 and R = 0.17, P = 0.009, respectively). In logistic regression analysis, BMI was positively associated with the presence of vertebral fractures independent of age and other traditional risk factors for fractures. Including weight and height instead of BMI in the multivariate model, showed weight as a positive and significant covariate of the presence of vertebral fractures (OR = 1.045; P = 0.016; 95% CI 1.008-1.084). BMI was associated with the number of vertebral fractures (rho = 0.18; P = 0.001), this association being confirmed also in the multivariate analysis (beta = 0.14; P = 0.03) after correction for smoking, early menopause, family history of fragility fractures and BMD. In conclusion, among postmenopausal women with osteoporosis, body weight and BMI are associated with a higher likelihood of having a vertebral fracture, irrespective of the positive association between weight and BMD.

The evolution of fracture surface roughness and its dependence on slip

NASA Astrophysics Data System (ADS)

Wells, Olivia L.

Under effective compression, impingement of opposing rough surfaces of a fracture can force the walls of the fracture apart during slip. Therefore, a fracture's surface roughness exerts a primary control on the amount of dilation that can be sustained on a fracture since the opposing surfaces need to remain in contact. Previous work has attempted to characterize fracture surface roughness through topographic profiles and power spectral density analysis, but these metrics describing the geometry of a fracture's surface are often non-unique when used independently. However, when combined these metrics are affective at characterizing fracture surface roughness, as well as the mechanisms affecting changes in roughness with increasing slip, and therefore changes in dilation. These mechanisms include the influence of primary grains and pores on initial fracture roughness, the effect of linkage on locally increasing roughness, and asperity destruction that limits the heights of asperities and forms gouge. This analysis reveals four essential stages of dilation during the lifecycle of a natural fracture, whereas previous slip-dilation models do not adequately address the evolution of fracture surface roughness: (1) initial slip companied by small dilation is mediated by roughness controlled by the primary grain and pore dimensions; (2) rapid dilation during and immediately following fracture growth by linkage of formerly isolated fractures; (3) wear of the fracture surface and gouge formation that minimizes dilation; and (4) between slip events cementation that modifies the mineral constituents in the fracture. By identifying these fundamental mechanisms that influence fracture surface roughness, this new conceptual model relating dilation to slip has specific applications to Enhanced Geothermal Systems (EGS), which attempt to produce long-lived dilation in natural fractures by inducing slip.

Modelling deformation and fracture of Gilsocarbon graphite subject to service environments

NASA Astrophysics Data System (ADS)

Šavija, Branko; Smith, Gillian E.; Heard, Peter J.; Sarakinou, Eleni; Darnbrough, James E.; Hallam, Keith R.; Schlangen, Erik; Flewitt, Peter E. J.

2018-02-01

Commercial graphites are used for a wide range of applications. For example, Gilsocarbon graphite is used within the reactor core of advanced gas-cooled reactors (AGRs, UK) as a moderator. In service, the mechanical properties of the graphite are changed as a result of neutron irradiation induced defects and porosity arising from radiolytic oxidation. In this paper, we discuss measurements undertaken of mechanical properties at the micro-length-scale for virgin and irradiated graphite. These data provide the necessary inputs to an experimentally-informed model that predicts the deformation and fracture properties of Gilsocarbon graphite at the centimetre length-scale, which is commensurate with laboratory test specimen data. The model predictions provide an improved understanding of how the mechanical properties and fracture characteristics of this type of graphite change as a result of exposure to the reactor service environment.

The importance of pelvic ring stabilization as a life-saving measure in pre-hospital - A case report commented by autopsy.

PubMed

Durão, Carlos; Alves, Magda; Barros, André; Pedrosa, Frederico

2017-08-01

Hip fractures with unstable pelvic ring have great morbidity and mortality rates. These fractures result from high energy trauma such as falls from heights, road accidents and collapsing structures or other similar mechanisms of action. We report the case of a 63 years old man, construction worker, who stood inside a ditch during a wall construction when he was surprised by this collapse, which resulted in direct trauma to the right thigh and pelvis. The autopsy revealed diaphysis fracture of the right femur with an open book pelvic fracture with severe hemorrhagic infiltration and hematoma of the pelvic muscles without arterial injury. Bone bleeding and the vascular damage associated with disruption of the sacroiliac ligaments promote a very significant bleeding. Simple maneuvers such as sheet circumferential compression to promote pelvic ring closure are effective on stabilizing and closure of the sacroiliac joint. Hip manipulation of the fracture was performed during the necropsy to demonstrate and prove how a simple sheet contention can promote stabilization of the pelvic ring by closing the sacroiliac joints in open book fractures.

Effect of Speed (Centrifugal Load) on Gear Crack Propagation Direction

NASA Technical Reports Server (NTRS)

Lewicki, David G.

2001-01-01

The effect of rotational speed (centrifugal force) on gear crack propagation direction was explored. Gears were analyzed using finite element analysis and linear elastic fracture mechanics. The analysis was validated with crack propagation experiments performed in a spur gear fatigue rig. The effects of speed, rim thickness, and initial crack location on gear crack propagation direction were investigated. Crack paths from the finite element method correlated well with those deduced from gear experiments. For the test gear with a backup ratio (rim thickness divided by tooth height) of nib = 0.5, cracks initiating in the tooth fillet propagated to rim fractures when run at a speed of 10,000 rpm and became tooth fractures for speeds slower than 10,000 rpm for both the experiments and anal sis. From additional analysis, speed had little effect on crack propagation direction except when initial crack locations were near the tooth/rim fracture transition point for a given backup ratio. When at that point, higher speeds tended to promote rim fracture while lower speeds (or neglecting centrifugal force) produced tooth fractures.

Percutaneous reduction and fixation of an intra-articular calcaneal fracture using an inflatable bone tamp: description of a novel and safe technique

PubMed Central

2012-01-01

Calcaneal fractures are common injuries involving the hind foot and often a source of significant long-term morbidity. Treatment options have changed throughout the ages from periods of preferred nonoperative management to closed reduction with a mallet, and more recently, open reduction and anatomic internal fixation. The current treatment of choice; however, is often debated, as open management of these fractures carries many risks to include wound breakdown and infection. A less invasive form of surgical management through small incisions, while maintaining the ability to obtain joint congruency, anatomic alignment, and restore calcaneal height and width would be ideal. We propose a novel form of fracture reduction using an inflatable bone tamp and percutaneous fracture fixation. Preoperative planning and experienced fluoroscopy is crucial to successful management using this method. Although we achieved successful radiographic outcome in this case, long-term functional outcome of this technique are yet to be published. PMID:22420710

Rehabilitation of neglected Monteggia fracture: Dislocations in children.

PubMed

Yıldırım, Azad; Nas, Kemal

2017-11-06

There are limited studies related to the rehabilitation of neglected Monteggia fracture-dislocations. This study reports the results of the rehabilitation of neglected Monteggia fractures and dislocations and the best treatment options available. Thirteen children were rehabilitated between 2009 and 2012. A retrospective chart review was conducted to record the following: age, gender, anatomic region of fractures, time delay from symptom onset to fracture, Bado classification, Mayo Elbow Performance Index (MEPI) which includes pain, range of motion and daily life comfort, surgeries, length of hospitalization, location and pattern of fracture, length of follow-up and complications. The study group included thirteen children and adolescents; eleven males and two females with a mean age of 8.5 (range 2-15) years. According to the Bado classification, 11 patients had type 1, one had type 3 and one had type 4 fracture-dislocations. For Mayo Elbow Performance Index (MEPI) scales, patients that were less than ten years old had greater mean scores. Two patients had superficial infection, one had subluxation, one had osteoarthritis, one had delayed bone union and two had rigidity at the elbow. The goals of elbow rehabilitation following Neglected Monteggia cases include restoring function by restoring motion and muscle performance; influencing scar remodeling and preventing joint contracture; and restoring or maintaining joint stability. Patients aged younger than 10 years and intervals of less than one-year, between trauma and diagnosis, as well as early and effective rehabilitation were found as important parameters regarding favorable outcomes.

The Influence of Hydraulic Fracturing on Carbon Storage Performance

NASA Astrophysics Data System (ADS)

Fu, Pengcheng; Settgast, Randolph R.; Hao, Yue; Morris, Joseph P.; Ryerson, Frederick J.

2017-12-01

Conventional principles of the design and operation of geologic carbon storage (GCS) require injecting CO2 below the caprock fracturing pressure to ensure the integrity of the storage complex. In nonideal storage reservoirs with relatively low permeability, pressure buildup can lead to hydraulic fracturing of the reservoir and caprock. While the GCS community has generally viewed hydraulic fractures as a key risk to storage integrity, a carefully designed stimulation treatment under appropriate geologic conditions could provide improved injectivity while maintaining overall seal integrity. A vertically contained hydraulic fracture, either in the reservoir rock or extending a limited height into the caprock, provides an effective means to access reservoir volume far from the injection well. Employing a fully coupled numerical model of hydraulic fracturing, solid deformation, and matrix fluid flow, we study the enabling conditions, processes, and mechanisms of hydraulic fracturing during CO2 injection. A hydraulic fracture's pressure-limiting behavior dictates that the near-well fluid pressure is only slightly higher than the fracturing pressure of the rock and is insensitive to injection rate and mechanical properties of the formation. Although a fracture contained solely within the reservoir rock with no caprock penetration, would be an ideal scenario, poroelastic principles dictate that sustaining such a fracture could lead to continuously increasing pressure until the caprock fractures. We also investigate the propagation pattern and injection pressure responses of a hydraulic fracture propagating in a caprock subjected to heterogeneous in situ stress. The results have important implications for the use of hydraulic fracturing as a tool for managing storage performance.

Opposed-flow Flame Spread Over Solid Fuels in Microgravity: the Effect of Confined Spaces

NASA Astrophysics Data System (ADS)

Wang, Shuangfeng; Hu, Jun; Xiao, Yuan; Ren, Tan; Zhu, Feng

2015-09-01

Effects of confined spaces on flame spread over thin solid fuels in a low-speed opposing flow is investigated by combined use of microgravity experiments and computations. The flame behaviors are observed to depend strongly on the height of the flow tunnel. In particular, a non-monotonic trend of flame spread rate versus tunnel height is found, with the fastest flame occurring in the 3 cm high tunnel. The flame length and the total heat release rate from the flame also change with tunnel height, and a faster flame has a larger length and a higher heat release rate. The computation analyses indicate that a confined space modifies the flow around the spreading flame. The confinement restricts the thermal expansion and accelerates the flow in the streamwise direction. Above the flame, the flow deflects back from the tunnel wall. This inward flow pushes the flame towards the fuel surface, and increases oxygen transport into the flame. Such a flow modification explains the variations of flame spread rate and flame length with tunnel height. The present results suggest that the confinement effects on flame behavior in microgravity should be accounted to assess accurately the spacecraft fire hazard.

Talent identification model for sprinter using discriminant factor

NASA Astrophysics Data System (ADS)

Kusnanik, N. W.; Hariyanto, A.; Herdyanto, Y.; Satia, A.

2018-01-01

The main purpose of this study was to identify young talented sprinter using discriminant factor. The research was conducted in 3 steps including item pool, screening of item pool, and trial of instruments at the small and big size of samples. 315 male elementary school students participated in this study with mean age of 11-13 years old. Data were collected by measuring anthropometry (standing height, sitting height, body mass, and leg length); testing physical fitness (40m sprint for speed, shuttle run for agility, standing broad jump for power, multistage fitness test for endurance). Data were analyzed using discriminant factor. The result of this study found that there were 5 items that selected as an instrument to identify young talented sprinter: sitting height, body mass, leg length, sprint 40m, and multistage fitness test. Model of Discriminant for talent identification in sprinter was D = -24,497 + (0,155 sitting height) + (0,080 body mass) + (0,148 leg length) + (-1,225 Sprint 40m) + (0,563 MFT). The conclusion of this study: instrument tests that have been selected and discriminant model that have been found can be applied to identify young talented as a sprinter.

Influence of clinical baseline findings on the survival of 2 post systems: a randomized clinical trial.

PubMed

Schmitter, Marc; Rammelsberg, Peter; Gabbert, Olaf; Ohlmann, Brigitte

2007-01-01

The aim of this prospective randomized controlled trial was to evaluate the influence of clinical baseline characteristics on the survival of 2 post systems. One hundred patients needing a post were included. Half the patients received a glass fiber-reinforced post (FRP), and the other half received metal screw posts (MSP). The posts were assigned randomly. In addition to demographic data, the following parameters were recorded: type of tooth (incisor/canine versus molar/premolar), length of the post in relation to root length (percentage), extent of coronal tooth destruction (percentage), ferrule height (in millimeters), type of restoration (fixed or removable partial denture), and presence of antagonistic contacts (yes/no). After at least 1 year (mean: 13.84 months), the patients were recalled. Statistical analysis was performed using the log-rank test and Cox regression analysis. The survival rate of FRPs was 93.5%. In the MSP group, the survival rate was significantly lower (75.6%; log-rank test, P = .049). Additionally, the metal posts were associated with more unfavorable complications, for example, root fracture. The type of the tooth and the degree of coronal tooth destruction influenced the survival of MSPs, whereas no influence of these variables could be seen for FRPs. FRPs are superior to MSPs with respect to short-term clinical performance. Especially for MSPs, clinical survival depends on several variables.

Analysis of propagation mechanisms of stimulation-induced fractures in rocks

NASA Astrophysics Data System (ADS)

Krause, Michael; Renner, Joerg

2016-04-01

Effectivity of geothermal energy production depends crucially on the heat exchange between the penetrated hot rock and the circulating water. Hydraulic stimulation of rocks at depth intends to create a network of fractures that constitutes a large area for exchange. Two endmembers of stimulation products are typically considered, tensile hydro-fractures that propagate in direction of the largest principal stress and pre-existing faults that are sheared when fluid pressure reduces the effective normal stress acting on them. The understanding of the propagation mechanisms of fractures under in-situ conditions is still incomplete despite intensive research over the last decades. Wing-cracking has been suggested as a mechanism of fracture extension from pre-existent faults with finite length that are induced to shear. The initiation and extension of the wings is believed to be in tensile mode. Open questions concern the variability of the nominal material property controlling tensile fracture initiation and extension, the mode I facture toughness KIC, with in-situ conditions, e.g., its mean-stress dependence. We investigated the fracture-propagation mechanism in different rocks (sandstones and granites) under varying conditions mimicking those representative for geothermal systems. To determine KIC-values we performed 3-point bending experiments. We varied the confining pressure, the piston velocity, and the position of the chevron notch relative to the loading configuration. Additional triaxial experiments at a range of confining pressures were performed to study wing crack propagation from artificial flaws whose geometrical characteristics, i.e., length, width, and orientation relative to the axial load are varied. We monitored acoustic emissions to constrain the spacio-temporal evolution of the fracturing. We found a significant effect of the length of the artificial flaw and the confining pressure on wing-crack initiation but did not observe a systematic dependence of wing-crack initiation on the orientation of the initial flaw in the range of tested angles. In fact, wings do not develop for artificial flaws shorter than 3 mm. The force required to initiate wing cracking increases with increasing confining pressure as does the apparent fracture toughness. So called ``anti-wing cracks'' were observed too, probably an artifact of the geometrical constraints imposed on the sample in a conventional triaxial compression test.

Plantar fascia coronal length: a new parameter for plantar fascia assessment.

PubMed

Sari, Ahmet Sinan; Demircay, Emre; Cakmak, Gokhan; Sahin, M Sukru; Tuncay, I Cengiz; Altun, Suleyman

2015-01-01

The effects of gender and various anthropometric variables were previously reported as significant predictors of plantar fascia thickness. Although a strong correlation between either the body weight or body mass index (BMI) and plantar fascia thickness were not demonstrated, a moderate relation was stated. We retrospectively investigated the role of gender, height, weight, and body mass index on plantar fascia thickness at the calcaneal origin (PFCO) and 1 cm distal from the calcaneal origin (PF1cm) and the coronal length of the plantar fascia at the calcaneal origin (CLPF) in healthy subjects. The PFCO, PF1cm, and CLPF were retrospectively measured from magnetic resonance images of 100 healthy subjects. The gender, height, weight, and body mass index of the participants were also noted. Gender was a predictive factor for the length of the CLPF. The subjects with a BMI >25 kg/m(2) had a significantly greater PFCO, PF1cm, and CLPF. Height was mildly and BMI and weight were moderately related to the PFCO. However the CLPF showed a better correlation with height, BMI, and weight than that of plantar fascia thickness. CLPF better reflected the role of weight, BMI, and height than its thickness. It is a new parameter that could be valuable in the evaluation of plantar fascia disorders. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

The economic impact of surgically treated peri-prosthetic hip fractures on a university teaching hospital in Wales 7.5-year study.

PubMed

Jones, Andrew R; Williams, Tim; Paringe, Vishal; White, Simon P

2016-02-01

The number of total hip replacements taking place across the UK continues to grow. In an ageing population, with people placing greater demands on their prostheses, the number of peri-prosthetic fractures is increasing. We studied the economic impact this has on a large teaching hospital. All patients with peri-prosthetic femoral fracture in a 7.5 year period were identified. Radiographic and case note analysis was performed. Costings from the finance departments were obtained. 90 cases were identified, 58 female and 32 male, with a mean age of 76 (range: 38-91). 89 of the cases were managed surgically, 66% undergoing revision and 33% receiving open reduction and internal fixation. According to the Vancouver Classification, 3% were Type A, 79% Type B and 18% Type C. The mean length of stay was 43 days. The mean cost of management was £31,370 (range: £6885-£112,327). Patients with type C fractures had the highest mean length of stay at 53 days and mean cost of £33,417. Including rehabilitation costs, our study illustrated a mean cost of £31,370, roughly four times the current basic NHS tariff of £8552. Although implant costs are greater, treatment with revision where appropriate allows earlier weight bearing, reduced length of stay and lower overall cost. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of Irrigation Times Using Gravity and High-Pressure Lavage.

PubMed

Muscatelli, Stefano; Howe, Andrea; O'Hara, Nathan N; O'Toole, Robert V; Sprague, Sheila A; Slobogean, Gerard P

2017-05-01

The benefits of high-pressure pulsatile lavage for open fracture irrigation have been controversial based on conflicting experimental animal research. Recently published data definitively demonstrated that irrigation pressure does not affect the incidence of reoperation for the treatment of open fractures. However, proponents of pulsatile lavage argue a faster irrigation time is an important benefit of the high-pressure treatment. The purpose of this study was to determine the difference in irrigation time between gravity and high-pressure lavage. The experimental setup was designed to mimic clinical practice and compared mean irrigation flow times for high-pressure pulsatile lavage and gravity flow with 2 commonly used tube diameters. Each irrigation setup was tested 5 times at 3 different irrigation bag heights. Analysis of variance and Student's t tests were used to compare the mean flow times of 3 irrigation methods at each height and among the 3 heights for each irrigation method. The mean irrigation flow time in the various experimental models ranged from 161 to 243 seconds. Gravity irrigation with wide tubing was significantly faster than pulsatile lavage or gravity with narrow tubing (P<.001). Increasing irrigation bag height had only a marginal effect on the overall flow times (<9% difference). The difference in mean flow time among the testing techniques was slightly longer than 1 minute, which is unlikely to have a material impact on procedural costs, operating times, and subsequent gains in patient safety. [Orthopedics. 2017; 40(3):e413-e416.]. Copyright 2017, SLACK Incorporated.

[Characteristics of growth and development in children from families at social risk].

PubMed

Stojadinović, A

2001-01-01

Body height and weight are important indicators of children's health status. There are many evidences that children from disadvantaged families have lower height and weight than children of the same age from families without social risk. The aim of this study was to investigate characteristics of growth and development of children from economically disadvantaged families. The study was partly retrospective and partly prospective. The retrospective study included 509 children from disadvantaged families hospitalized at the Institute of Child and Adolescent Health Care in Novi Sad, during a five-year period. The prospective study included 90 children from disadvantaged families (experimental group) and 132 children from families without social risk (control group) hospitalized at the Institute during a six month period. Height/length, weight, head circumference, and psychomotor/intellectual development have been examined. In the retrospective study results were compared with theoretically expected values, whereas the prospective study results of experimental and control group were compared. In the retrospective study that included only children from disadvantaged families, 136 (26.7%) children had height/length, 173 (34%) had weight, and 86 (16.9%) children had head circumference below 10th percentile. Delay in psychomotor/intellectual development was established in 177 (34.8%) children. Children from families with social risk have significantly more often height/length, weight, head circumference and developmental delay than theoretically expected. In the prospective study 40 (44.4%) children from experimental group had height/length, 29 (32.2%) had weight, 20 (22.2%) children had head circumference below 10th percentile, and 17 (26.2%) had delay in psychomotor/intellectual development. Children from disadvantaged families (experimental group) significantly more often had delay in growth and development comparing with children from families without social risk (control group). Children from disadvantaged families significantly more often exhibit delay in growth and development, comparing with children of the same age from families without social risk. Therefore, pediatricians should consider social risk factors whenever treating children with growth or developmental delay.

Lamb Wave Propagation in a Restricted Geometry Composite PI-Joint Specimen (Preprint)

DTIC Science & Technology

2011-11-01

adhesive, and were located along the length and height of the specimen as depicted in Figure 3. The sensors were 6.35 mm round disks of PZT , with a...in both cases for R1, R2, and R3. 3D Finite Element Model Geometry 200mm length 50mm width 140mm height x z y PZT Actuation Sensor...health monitoring using scanning laser vibrometry: III. Lamb waves for fatigue crack detection”, Smart Mater. Struct., Vol. 14, No. 6, 2005. 16

Quasi-Brittle Fracture of Compact Specimens with Sharp Notches and U-Shaped Cuts

NASA Astrophysics Data System (ADS)

Kornev, V. M.; Demeshkin, A. G.

2018-01-01

A two-parameter (coupled) discrete-integral criterion of fracture is proposed. It can be used to construct fracture diagrams for compact specimens with sharp cracks. Curves separating the stress-crack length plane into three domains are plotted. These domains correspond to the absence of fracture, damage accumulation in the pre-fracture region under repeated loading, and specimen fragmentation under monotonic loading. Constants used for the analytical description of fracture diagrams for quasi-brittle materials with cracks are selected with the use of approximation of the classical stress-strain diagrams for the initial material and the critical stress intensity factor. Predictions of the proposed theory are compared with experimental results on fracture of compact specimens with different radii made of polymethylmethacrylate (PMMA) and solid rubber with crack-type effects in the form of U-shaped cuts.

Operative Fixation of Rib Fractures Indications, Techniques, and Outcomes.

PubMed

Galos, David; Taylor, Benjamin; McLaurin, Toni

2017-01-01

Rib fractures are extremely common injuries and vary in there severity from single nondisplaced fractures to multiple segmental fractures resulting in flail chest and respiratory compromise. Historically, rib fractures have been treated conservatively with pain control and respiratory therapy. However this method may not be the best treatment modality in all situations. Operative fixation of select rib fractures has been increasing in popularity especially in patients with flail chest and respiratory compromise. Newer techniques use muscle sparing approaches and precontoured locking plate technology to obtain stable fixation and allow improved respiration. Current reports shows that rib fracture fixation offers the benefits of improved respiratory mechanics and improved pain control in the severe chest wall injury with resultant improvement in patient outcomes by decreasing time on the ventilator, time in the intensive care unit, and overall hospital length of stay.

The effects of shot-peening residual stresses on the fracture and crack growth properties of D6AC steel

NASA Technical Reports Server (NTRS)

Elber, W.

1973-01-01

The fracture strength and cyclic crack-growth properties of surface-flawed, shot-peened D6AC steel plate were investigated. For short crack lengths (up to 1.5mm) simple linear elastic fracture mechanics - based only on applied loading - did not predict the fracture strengths. Also, Paris' Law for cyclic crack growth did not correlate the crack-growth behavior. To investigate the effect of shot-peening, additional fracture and crack-growth tests were performed on material which was precompressed to remove the residual stresses left by the shot-peening. Both tests and analysis show that the shot-peening residual stresses influence the fracture and crack-growth properties of the material. The analytical method of compensating for residual stresses and the fracture and cyclic crack-growth test results and predictions are presented.

Effects of shot-peening residual stresses on the fracture and crack-growth properties of D6AC steel

NASA Technical Reports Server (NTRS)

Elber, W.

1974-01-01

The fracture strength and cyclic crack-growth properties of surface-flawed, shot-peened D6AC steel plate were investigated. For short crack lengths (up to 1.5 mm) simple linear elastic fracture mechanics - based only on applied loading - did not predict the fracture strengths. Also, Paris' Law for cyclic crack growth did not correlate the crack-growth behavior. To investigate the effect of shot-peening, additional fracture and crack-growth tests were performed on material which was precompressed to remove the residual stresses left by the shot-peening. Both tests and analysis show that shot-peening residual stresses influence the fracture and crack-growth properties of the material. This report presents the analytical method of compensating for residual stresses and the fracture and cyclic crack-growth test results and predictions.

Experimental investigation of the Heletz shale caprocks sealing capacity: implication for CO2 geological storage integrity

NASA Astrophysics Data System (ADS)

Abdoulghafour, Halidi; Gouze, Philippe; Luquot, Linda; Arif, Mohamed; Iglauer, Stefan

2017-04-01

Using a combination of core flooding experiments and wettability measurements, we evaluate the sealing efficiency of Heletz caprock under CO2 sequestration conditions. The flow through experiments consisted of flowing CO2 enriched fluid into two micro-fractured cylindrical cores (15 mm length - 9 mm diameter, with hydraulic aperture: 2.7 µm for the sample named H18A and 13 µm for sample named H18B) and monitoring the permeability changes, the evolution of the chemistry from the inlet and outlet fluid. The changes in microstructures and mineralogy were also studied using an environmental scanning electrons microscope (ESEM) and X-ray micro-tomography (XRMT) images. The fracture permeability was found to decrease significantly in the two experiments from 14.1×10-12 m2 to 5.0×10-12 m2 for experiment H18B and from 6.5×10-13 m2 to 2.8×10-13 m2 for experiment H18A. Calcite dissolution and reconversion of k-feldspar to illite and kaolinite were the main reaction on sample H18B while "calcite precipitation" in batch condition was the dominant reaction on sample H18A. Accordingly, the decrease in permeability was induced by the dispersion of dissolution products and the re-organization of clay particles within the fracture for sample H18B as shown by micro-tomography and ESEM images. The fracture healing due to the calcite and clay mineral precipitation along the fracture was attested by ESEM image for sample H18A. The results of capillary pressure breakthrough calculated by applying the Washburn equation and the reservoir scaling method from intrusion of mercury are approximately 380 kPa and 310 kPa for H18B and H18A respectively. Although, these values are sensibly different but close to each other and in good agreement to indicate the weak storage capacity of the heletz caprock. Subsequently less than 90 m of CO2 column height can be efficiently stored in the Heletz reservoir. Thus the self-mitigation of the CO2 leakage is expected only when few quantity of CO2 will be injected.

Early anthropometric indices predict short stature and overweight status in a cohort of Peruvians in early adolescence

PubMed Central

Sterling, Robie; Miranda, J Jaime; Gilman, Robert H; Cabrera, Lilia; Sterling, Charles R; Bern, Caryn; Checkley, William

2014-01-01

While childhood malnutrition is associated with increased morbidity and mortality, less well understood is how early childhood growth influences height and body composition later in life. We revisited 152 Peruvian children who participated in a birth cohort study between 1995 and 1998, and obtained anthropometric and bioimpedance measurements 11 to 14 years later. We used multivariable regression models to study the effects of childhood anthropometric indices on height and body composition in early adolescence. Each standard deviation decrease in length-for-age at birth was associated with a decrease in adolescent height-for-age of 0.7 SD in both boys and girls (all p<0.001) and 9.7 greater odds of stunting (95% CI 3.3 to 28.6). Each SD decrease in length-for-age in the first 30 months of life was associated with a decrease in adolescent height-for-age of 0.4 in boys and 0.6 standard deviation in girls (all p<0.001) and with 5.8 greater odds of stunting (95% CI 2.6 to 13.5). The effect of weight gain during early childhood on weight in early adolescence was more complex to understand. Weight-for-length at birth and rate of change in weight-for-length in early childhood were positively associated with age- and sex-adjusted body mass index and a greater risk of being overweight in early adolescence. Linear growth retardation in early childhood is a strong determinant of adolescent stature, indicating that, in developing countries, growth failure in height during early childhood persists through early adolescence. Interventions addressing linear growth retardation in childhood are likely to improve adolescent stature and related-health outcomes in adulthood. PMID:22552904

Early anthropometric indices predict short stature and overweight status in a cohort of Peruvians in early adolescence.

PubMed

Sterling, Robie; Miranda, J Jaime; Gilman, Robert H; Cabrera, Lilia; Sterling, Charles R; Bern, Caryn; Checkley, William

2012-07-01

While childhood malnutrition is associated with increased morbidity and mortality, less well understood is how early childhood growth influences height and body composition later in life. We revisited 152 Peruvian children who participated in a birth cohort study between 1995 and 1998, and obtained anthropometric and bioimpedance measurements 11-14 years later. We used multivariable regression models to study the effects of childhood anthropometric indices on height and body composition in early adolescence. Each standard deviation decrease in length-for-age at birth was associated with a decrease in adolescent height-for-age of 0.7 SD in both boys and girls (all P < 0.001) and 9.7 greater odds of stunting (95% CI 3.3-28.6). Each SD decrease in length-for-age in the first 30 months of life was associated with a decrease in adolescent height-for-age of 0.4 in boys and 0.6 standard deviation in girls (all P < 0.001) and with 5.8 greater odds of stunting (95% CI 2.6-13.5). The effect of weight gain during early childhood on weight in early adolescence was more complex to understand. Weight-for-length at birth and rate of change in weight-for-length in early childhood were positively associated with age- and sex-adjusted body mass index and a greater risk of being overweight in early adolescence. Linear growth retardation in early childhood is a strong determinant of adolescent stature, indicating that, in developing countries, growth failure in height during early childhood persists through early adolescence. Interventions addressing linear growth retardation in childhood are likely to improve adolescent stature and related-health outcomes in adulthood. Copyright © 2012 Wiley Periodicals, Inc.