[CHANGES OF THE HEMOSTASIS SYSTEM IN THE INJURED PERSONS IN FRACTURES OF LONG BONES OF THE LOWER EXTREMITIES].

PubMed

Tarabrin, O O; Grichushenko, I S

2015-09-01

The changes of hemostasis in the injured persons, in the lower extremities long bones fracture were analyzed. Complex dynamic investigation of the hemostasis system was conducted preoperatively in 76 injured persons, in whom long bones of the lower extremities fracture have occurred, and in 31--with injury of meniscus. Instrumental diagnostic method--a low-frequency piezoelectric thromboelastography--was applied for investigation of the blood coagulation system. The shift in a system of hemostasis towards hypercoagulation, fibrinolytic and the thrombine activity inhibition, the thrombocytes spontaneous aggregation intensity, duration of formation of a clot fibrinthrombocytic structure; the blood fibrinthrombocytic constanta enhancement, a summary index of the clot retraction and spontaneous lysis reduction were revealed in a hemostasis system before start of the treatment. The hemostasis system disorders in the injured persons may cause thrombohemorrhagic complications, what trusts a necessity for rational choice of preoperative methods of prophylaxis and intensive therapy in a system of hemostasis.

[Bone fracture and the healing mechanisms. The role of BMP signaling in fracture healing].

PubMed

Imai, Yuuki; Takaoka, Kunio

2009-05-01

When bone tissue, which plays a central role in locomotive organs, is broken by trauma and decreased in its own function of support, it is lead to be remarkable decline in the activity of daily life (ADL). Recently, in a clinical situation, various treatments have been tried for prophylaxis of fractures, and these treatments have been rewarded with good results. However, fractures would be occurred in a certain amount and there would be serious problems in ADL if the treatment fails to repair fractures. Furthermore, fractures could spontaneously heal in several weeks, it can be achieved in early rehabilitation and improvement of ADL, if we can accelerate fracture healing. Bone morphogenetic proteins, which were advocated by Dr. Urist, would be expected to be a key to establish much better society especially for the old.

On Subsurface Fracture Opening and Closure

NASA Astrophysics Data System (ADS)

Wang, Y.

2016-12-01

Mechanistic understanding of fracture opening and closure in geologic media is of significant importance to nature resource extraction and waste management, such as geothermal energy extraction, oil/gas production, radioactive waste disposal, and carbon sequestration and storage). A dynamic model for subsurface fracture opening and closure has been formulated. The model explicitly accounts for the stress concentration around individual aperture channels and the stress-activated mineral dissolution and precipitation. A preliminary model analysis has demonstrated the importance of the stress-activated dissolution mechanism in the evolution of fracture aperture in a stressed geologic medium. The model provides a reasonable explanation for some key features of fracture opening and closure observed in laboratory experiments, including a spontaneous switch from a net permeability reduction to a net permeability increase with no changes in a limestone fracture experiment.

Effect of Time and Temperature on Transformation Toughened Zirconias.

DTIC Science & Technology

1987-06-01

room temperature. High temperature mechanical tests performed vere stress rupture and stepped temperature stress rupture. The results of the tests...tetragonal precipitates will spontaneously transform to the monoclinic phae due to the lattice mismatch stress if they become larger than about 0.2 on, with...specimens, including fast fracture and fracture toughness testing. High temper- ture testing consisting of stress rupture and stepped temperature stress

Bilateral cataract formation via acute spontaneous fracture of the lens following treatment of hyperglycemic hyperosmolar syndrome.

PubMed

Sychev, Yevgeniy V; Zepeda, Emily M; Lam, Deborah L

2017-09-01

Acute development of cataracts that may be transient is known to occur during correction of diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome. Nettleship in 1885 was the first to describe the presence of a transient cataract in three diabetic patients that grew worse and eventually cleared with treatment. 1 We present a case of irreversible cataracts formed by nuclear fracture of the crystalline lens after hyperglycemia correction, an entity that has not yet been described. A 67 year-old Caucasian man presented with sudden bilateral vision loss one week after a week-long hospitalization in the intensive care unit for correction of hyperglycemia in the setting of hyperglycemic hyperosmolar syndrome requiring an insulin drip. This was caused by spontaneous fractures of the lens nuclei causing bilateral irreversible cataracts. The patient underwent uncomplicated bilateral cataract extraction resulting in restoration of normal vision. Acute transient cataracts that develop during correction of hyperglycemic hyperosmolar syndrome are thought to result from osmotic lens swelling. In this case report, internal fracture of the lens was produced by mechanical forces generated in the process of lens swelling occurring as a consequence of initial hyperglycemia and its subsequent correction. This case represents a rare ocular complication of hyperglycemia correction, and provides new evidence that mechanical forces can be part of diabetic cataractogenesis.

Risk of refracture through unicameral bone cysts of the proximal femur.

PubMed

Norman-Taylor, Fabian H; Hashemi-Nejad, Aresh; Gillingham, Bruce L; Stevens, David; Cole, William G

2002-01-01

The authors determined the results after traction or traction and hip spica treatment of the initial fractures through unicameral bone cysts of the proximal femur in 20 children. All of the eight displaced fractures healed, but with coxa vara and avascular necrosis in one, coxa vara in a second, and coxa breva in a third. Spontaneous healing of the cyst occurred in three of the eight children; satisfactory healing was achieved and maintained after intralesional corticosteroid injections in four of the eight children. In the remaining child with a displaced fracture, reactivation of the cyst and exercise-related pain, indicative of an incipient refracture, occurred 3 years after initial presentation. All of the 12 undisplaced fractures healed without deformity or avascular necrosis. Intralesional corticosteroids were used in all of the 12 children because none of them showed spontaneous healing of their cysts. Satisfactory radiographic healing was achieved 1 year after presentation in all of the 12 children. However, one or more refractures resulting from reactivation of the cyst occurred in 6 of the 12 children 2 to 5 years after initial presentation. The results of this study indicate that satisfactory radiographic healing needs to be achieved by the end of the first year and needs to be maintained thereafter to prevent refractures.

Spontaneous patella fracture associated with anterior tibial tubercle pseudarthrosis in a revised knee replacement following knee Arthrodesis

PubMed Central

2013-01-01

Background Conversion of a knee arthrodesis to a Total Knee Arthroplasty is an uncommon procedure. Revision Total Knee Arthroplasty in this setting presents the surgeon with a number of challenges including the management of the extensor mechanism and patella. Case presentation We describe a unique case of a 69 years old Caucasian man who underwent a revision Total Knee Arthroplasty using a tibial tubercle osteotomy after a previous conversion of a knee arthrodesis without patella resurfacing. Unfortunately 9 months following surgery a tibial tubercle pseudarthrosis and spontaneous patella fracture occurred. Both were managed with open reduction and internal fixation. At 30 months follow-up the tibial tubercle osteotomy had completely consolidated while the patella fracture was still evident but with no signs of further displacement. The patient was completely satisfied with the outcome and had a painless range of knee flexion between 0-95°. Conclusions We believe that patients undergoing this type of surgery require careful counseling regarding the risk of complications both during and after surgery despite strong evidence supporting improved functional outcomes. PMID:24195600

Overexpression of BMP3 in the developing skeleton alters endochondral bone formation resulting in spontaneous rib fractures.

PubMed

Gamer, Laura W; Cox, Karen; Carlo, Joelle M; Rosen, Vicki

2009-09-01

Bone morphogenetic protein-3 (BMP) has been identified as a negative regulator in the skeleton as mice lacking BMP3 have increased bone mass. To further understand how BMP3 mediates bone formation, we created transgenic mice overexpressing BMP3 using the type I collagen promoter. BMP3 transgenic mice displayed spontaneous rib fractures that were first detected at E17.0. The fractures were due to defects in differentiation of the periosteum and late hypertrophic chondrocytes resulting in thinner cortical bone with decreased mineralization. As BMP3 modulates BMP and activin signaling through ActRIIB, we examined the ribs of ActRIIB receptor knockout mice and found they had defects in late chondrogenesis and mineralization similar to BMP3 transgenic mice. These data suggest that BMP3 exerts its effects in the skeleton by altering signaling through ActRIIB in chondrocytes and the periosteum, and this results in defects in bone collar formation and late hypertrophic chondrocyte maturation leading to decreased mineralization and less bone. 2009 Wiley-Liss, Inc.

Severe humeral erosion in a bedridden patient: a comprehensive intervention to prevent bone fracture.

PubMed

Ferriero, Giorgio; Brunetto, Alessandro; Sartorio, Francesco; Vercelli, Stefano

2004-12-01

This article reports a 1-yr prospective study related to a bedridden patient with rotator cuff tear arthropathy featuring severe erosion of the proximal part of the humerus. To prevent spontaneous humeral fracture, a comprehensive intervention was planned. This included drug therapy for osteoporosis and pain, nurse team training on patient handling techniques, and patient and caregiver education. After 1 yr, clinical and radiologic findings are stable.

Stress fracture of the pelvis and lower limbs including atypical femoral fractures-a review.

PubMed

Tins, Bernhard J; Garton, Mark; Cassar-Pullicino, Victor N; Tyrrell, Prudencia N M; Lalam, Radhesh; Singh, Jaspreet

2015-02-01

Stress fractures, that is fatigue and insufficiency fractures, of the pelvis and lower limb come in many guises. Most doctors are familiar with typical sacral, tibial or metatarsal stress fractures. However, even common and typical presentations can pose diagnostic difficulties especially early after the onset of clinical symptoms. This article reviews the aetiology and pathophysiology of stress fractures and their reflection in the imaging appearances. The role of varying imaging modalities is laid out and typical findings are demonstrated. Emphasis is given to sometimes less well-appreciated fractures, which might be missed and can have devastating consequences for longer term patient outcomes. In particular, atypical femoral shaft fractures and their relationship to bisphosphonates are discussed. Migrating bone marrow oedema syndrome, transient osteoporosis and spontaneous osteonecrosis are reviewed as manifestations of stress fractures. Radiotherapy-related stress fractures are examined in more detail. An overview of typical sites of stress fractures in the pelvis and lower limbs and their particular clinical relevance concludes this review. Teaching Points • Stress fractures indicate bone fatigue or insufficiency or a combination of these. • Radiographic visibility of stress fractures is delayed by 2 to 3 weeks. • MRI is the most sensitive and specific modality for stress fractures. • Stress fractures are often multiple; the underlying cause should be evaluated. • Infratrochanteric lateral femoral fractures suggest an atypical femoral fracture (AFF); endocrinologist referral is advisable.

Phase-field simulation of counter-current spontaneous imbibition in a fractured heterogeneous porous medium

NASA Astrophysics Data System (ADS)

Rokhforouz, M. R.; Akhlaghi Amiri, H. A.

2017-06-01

Spontaneous imbibition is well-known to be one of the most effective processes of oil recovery in fractured reservoirs. However, the detailed pore-scale mechanisms of the counter-current imbibition process and the effects of different fluid/rock parameters on this phenomenon have not yet been deeply addressed. This work presents the results of a new pore-level numerical study of counter-current spontaneous imbibition, using coupled Cahn-Hilliard phase field and Navier-Stokes equations, solved by a finite element method. A 2D fractured medium was constructed consisting of a nonhomogeneous porous matrix, in which the grains were represented by an equilateral triangular array of circles with different sizes and initially saturated with oil, and a fracture, adjacent to the matrix, initially saturated with water and supported by low rate water inflow. Through invasion of water into the matrix, oil drops were expelled one by one from the matrix to the fracture, and in the matrix, water progressed by forming capillary fingerings, with characteristics corresponding to the experimental observations. The effects of wettability, viscosity ratio, and interfacial tension were investigated. In strongly water-wet matrix, with grain contact angles of θ < π/8, different micro-scale mechanisms were successfully captured, including oil film thinning and rupture, fluids' contact line movement, water bridging, and oil drop detachment. It was notified that there was a specific grain contact angle for this simulated model, θ = π/4, above it, matrix oil recovery was negligible by imbibition, while below it, the imbibition rate and oil recovery were significantly increased by decreasing the contact angle. In simulated mixed wet models, water, coming from the fracture, just invaded the neighboring water-wet grains; the water front was stopped moving as it met the oil-wet grains or wide pores/throats. Increasing water-oil interfacial tension, in the range of 0.005-0.05 N/m, resulted in both higher rate of imbibition and higher ultimate oil recovery. Changing the water-oil viscosity ratio (M), in the range of 0.1-10, had a negligible effect on the imbibition rate, while due to co-effects of capillary fingering and viscous mobility ratio, the model with M = 1 had relatively higher ultimate oil recovery.

Capillary Imbibition of Hydraulic Fracturing Fluids into Partially Saturated Shale

NASA Astrophysics Data System (ADS)

Birdsell, D.; Rajaram, H.; Lackey, G.

2015-12-01

Understanding the migration of hydraulic fracturing fluids injected into unconventional reservoirs is important to assess the risk of aquifer contamination and to optimize oil and gas production. Capillary imbibition causes fracturing fluids to flow from fractures into the rock matrix where the fluids are sequestered for geologically long periods of time. Imbibition could explain the low amount of flowback water observed in the field (5-50% of the injected volume) and reduce the chance of fracturing fluid migrating out of formation towards overlying aquifers. We present calculations of spontaneous capillary imbibition in the form of an "imbibition rate parameter" (A) based on the only known exact analytical solution for spontaneous capillary imbibition. A depends on the hydraulic and capillary properties of the reservoir rock, the initial water saturation, and the viscosities of the wetting and nonwetting fluids. Imbibed volumes can be large for a high permeability shale gas reservoir (up to 95% of the injected volume) or quite small for a low permeability shale oil reservoir (as low as 3% of the injected volume). We also present a nondimensionalization of the imbibition rate parameter, which facilitates the calculation of A and clarifies the relation of A to initial saturation, porous medium properties, and fluid properties. Over the range of initial water saturations reported for the Marcellus shale (0.05-0.6), A varies by less than factors of ~1.8 and ~3.4 for gas and oil nonwetting phases respectively. However, A decreases significantly for larger initial water saturations. A is most sensitive to the intrinsic permeability of the reservoir rock and the viscosity of the fluids.

Novel compound heterozygous mutations identified by whole exome sequencing in a Japanese patient with geroderma osteodysplastica.

PubMed

Takeda, Ryojun; Takagi, Masaki; Shinohara, Hiroyuki; Futagawa, Hiroshi; Narumi, Satoshi; Hasegawa, Tomonobu; Nishimura, Gen; Yoshihashi, Hiroshi

2017-12-01

Geroderma osteodysplastica (GO) is a subtype of cutis laxa syndrome characterized by congenital wrinkly skin, a prematurely aged face, extremely short stature, and osteoporosis leading to recurrent fractures. GO exhibits an autosomal recessive inheritance pattern and is caused by loss-of-function mutations in GORAB, which encodes a protein important for Golgi-related transport. Using whole exome sequencing, we identified novel compound heterozygous nonsense mutations in the GORAB in a GO patient. The patient was a 14-year-old Japanese boy. Wrinkled skin and joint laxity were present at birth. At 1 year of age, he was clinically diagnosed with cutis laxa syndrome based on recurrent long bone fractures and clinical features, including wrinkled skin, joint laxity, and a distinctive face. He did not show retarded gross motor and cognitive development. At 11 years of age, he was treated with oral bisphosphonate and vitamin D owing to recurrent multiple spontaneous fractures of the vertebral and extremity bones associated with a low bone mineral density (BMD). Bisphosphonate treatment improved his BMD and fracture rate. Whole exome sequencing revealed two novel compound heterozygous nonsense mutations in the GORAB gene (p.Arg60* and p.Gln124*), and the diagnosis of GO was established. GO is a rare connective tissue disorder. Approximately 60 cases have been described to date, and this is the first report of a patient from Japan. Few studies have reported the effects of bisphosphonate treatment in GO patients with recurrent spontaneous fractures. Based on this case study, we hypothesize that oral bisphosphonate and vitamin D are effective and safe treatment options for the management of recurrent fractures in GO patients. It is important to establish a precise diagnosis of GO to prevent recurrent fractures and optimize treatment plans. Copyright © 2017 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.

Osteoblast-derived WNT16 represses osteoclastogenesis and prevents cortical bone fragility fractures

PubMed Central

Movérare-Skrtic, Sofia; Henning, Petra; Liu, Xianwen; Nagano, Kenichi; Saito, Hiroaki; Börjesson, Anna E; Sjögren, Klara; Windahl, Sara H; Farman, Helen; Kindlund, Bert; Engdahl, Cecilia; Koskela, Antti; Zhang, Fu-Ping; Eriksson, Emma E; Zaman, Farasat; Hammarstedt, Ann; Isaksson, Hanna; Bally, Marta; Kassem, Ali; Lindholm, Catharina; Sandberg, Olof; Aspenberg, Per; Sävendahl, Lars; Feng, Jian Q; Tuckermann, Jan; Tuukkanen, Juha; Poutanen, Matti; Baron, Roland; Lerner, Ulf H; Gori, Francesca; Ohlsson, Claes

2015-01-01

The WNT16 locus is a major determinant of cortical bone thickness and nonvertebral fracture risk in humans. The disability, mortality and costs caused by osteoporosis-induced nonvertebral fractures are enormous. We demonstrate here that Wnt16-deficient mice develop spontaneous fractures as a result of low cortical thickness and high cortical porosity. In contrast, trabecular bone volume is not altered in these mice. Mechanistic studies revealed that WNT16 is osteoblast derived and inhibits human and mouse osteoclastogenesis both directly by acting on osteoclast progenitors and indirectly by increasing expression of osteoprotegerin (Opg) in osteoblasts. The signaling pathway activated by WNT16 in osteoclast progenitors is noncanonical, whereas the pathway activated in osteoblasts is both canonical and noncanonical. Conditional Wnt16 inactivation revealed that osteoblast-lineage cells are the principal source of WNT16, and its targeted deletion in osteoblasts increases fracture susceptibility. Thus, osteoblast-derived WNT16 is a previously unreported key regulator of osteoclastogenesis and fracture susceptibility. These findings open new avenues for the specific prevention or treatment of nonvertebral fractures, a substantial unmet medical need. PMID:25306233

Analysis of horse race videos to identify intra-race risk factors for fatal distal limb fracture.

PubMed

Parkin, T D H; Clegg, P D; French, N P; Proudman, C J; Riggs, C M; Singer, E R; Webbon, P M; Morgan, K L

2006-04-17

The objective of this study was to identify risk factors, during racing, associated with imminent fatal distal limb fracture in Thoroughbreds. One hundred and nine cases of fatal distal limb fracture were identified from all 59 UK racecourses over a 2-year period (February 1999-January 2001). Three uninjured control horses were randomly selected from the same race as the case horse. Videos of races in which fractures occurred were viewed using a defined protocol. Fractures in flat races occurred at any time during the race, whereas 74% (45/61) of cases in national hunt type races occurred in the second half of races. More than 75% (79/103) of cases were spontaneous, i.e. there was no obvious external influence such as a fall at a fence or collision with another horse. Sixty-six percent (44/67) of horses, sustaining a forelimb fracture, fractured the forelimb they were using as lead leg at the time of fracture. When case and control horses were compared, horses that were: (a) making good progress through the race, (b) reluctant to start and (c) received encouragement in the final 10s before the time of fracture, were more likely to sustain a fracture.

[Osteosynthesis and cup revision in periprosthetic acetabulum fractures using a Kocher-Langenbeck approach].

PubMed

Schwabe, P; Märdian, S; Perka, C; Schaser, K-D

2016-04-01

Reconstruction/stable fixation of the acetabular columns to create an adequate periacetabular requirement for the implantation of a revision cup. Displaced/nondisplaced fractures with involvement of the posterior column. Resulting instability of the cup in an adequate bone stock situation. Periprosthetic acetabulum fractures with inadequate bone stock. Extended periacetabular defects with loss of anchorage options. Isolated periprosthetic fractures of the anterior column. Septic loosening. Dorsal approach. Dislocation of hip. Mechanical testing of inlaying acetabular cup. With unstable cup situation explantation of the cup, fracture fixation of acetabulum with dorsal double plate osteosynthesis along the posterior column. Cup revision. Hip joint reposition. Early mobilization; partial weight bearing for 12 weeks. Thrombosis prophylaxis. Clinical and radiological follow-ups. Periprosthetic acetabular fracture in 17 patients with 9 fractures after primary total hip replacement (THR), 8 after revision THR. Fractures: 12 due to trauma, 5 spontaneously; 7 anterior column fractures, 5 transverse fractures, 4 posterior column fractures, 1 two column fracture after hemiendoprosthesis. 5 type 1 fractures and 12 type 2 fractures. Operatively treated cases (10/17) received 3 reinforcement ring, 2 pedestal cup, 1 standard revision cup, cup-1 cage construct, 1 ventral plate osteosynthesis, 1 dorsal plate osteosynthesis, and 1 dorsal plate osteosynthesis plus cup revision (10-month Harris Hip Score 78 points). Radiological follow-up for 10 patients: consolidation of fractures without dislocation and a fixed acetabular cup. No revision surgeries during follow-up; 2 hip dislocations, 1 transient sciatic nerve palsy.

Spontaneous superior patellar dislocation in young age: case report and reduction technique

PubMed Central

Umar, Muhammad

2017-01-01

Abstract Superior patellar dislocation is a very rare pathology, which happens in middle age. We report a case of spontaneous superior patellar dislocation, which occurred at 30 years of age. Differential diagnosis is patellar tendon rupture, which could be reliably excluded by clinical examination and radiographs. Reduction manoeuvres should be tried with diluted intra-articular local anaesthetic for hydrodilatation to gain mechanical advantage. Splinting the knee in gentle flexion is recommended if general anaesthetic is employed. Recurrent dislocation or osteochondral fractures warrants surgical treatment. PMID:28458846

Dkk1 haploinsufficiency requires expression of Bmp2 for bone anabolic activity.

PubMed

Intini, Giuseppe; Nyman, Jeffry S

2015-06-01

Bone fractures remain a serious health burden and prevention and enhanced healing of fractures have been obtained by augmenting either BMP or Wnt signaling. However, whether BMP and Wnt signaling are both required or are self-sufficient for anabolic and fracture healing activities has never been fully elucidated. Mice haploinsufficient for Dkk1 (Dkk1(+/-)) exhibit a high bone mass phenotype due to an up-regulation of canonical Wnt signaling while mice lacking Bmp2 expression in the limbs (Bmp2(c/c);Prx1::cre) succumb to spontaneous fracture and are unable to initiate fracture healing; combined, these mice offer an opportunity to examine the requirement for activated BMP signaling on the anabolic and fracture healing activity of Wnts. When Dkk1(+/-) mice were crossed with Bmp2(c/c);Prx1::cre mice, the offspring bearing both genetic alterations were unable to increase bone mass and heal fractures, indicating that increased canonical Wnt signaling is unable to exploit its activity in absence of Bmp2. Thus, our data suggest that BMP signaling is required for Wnt-mediated anabolic activity and that therapies aimed at preventing fractures and fostering fracture repair may need to target both pathways for maximal efficacy. Copyright © 2015 Elsevier Inc. All rights reserved.

Dkk1 haploinsufficiency requires expression of Bmp2 for bone anabolic activity

PubMed Central

Intini, Giuseppe; Nyman, Jeffry S.

2015-01-01

Bone fractures remain a serious health burden and prevention and enhanced healing of fractures has been obtained by augmenting either BMP or Wnt signaling. However, whether BMP and Wnt signaling are both required or are self-sufficient for anabolic and fracture healing activities has never been fully elucidated. Mice haploinsufficient for Dkk1 (Dkk1+/−) exhibit a high bone mass phenotype due to an up-regulation of canonical Wnt signaling while mice lacking Bmp2 expression in the limbs (Bmp2c/c;Prx1::cre) succumb to spontaneous fracture and are unable to initiate fracture healing; combined, these mice offer an opportunity to examine the requirement for activated BMP signaling on the anabolic and fracture healing activity of Wnts. When Dkk1+/− mice were crossed with Bmp2c/c;Prx1::cre mice, the offspring bearing both genetic alterations were unable to increase bone mass and heal fractures, indicating that increased canonical Wnt signaling is unable to exploit its activity in absence of Bmp2. Thus, our data suggest that BMP signaling is required for Wnt-mediated anabolic activity and that therapies aimed at preventing fractures and fostering fracture repair may need to target both pathways for maximal efficacy. PMID:25603465

La syphilis congénitale révélée par une fracture spontanée

PubMed Central

Idrissi, Mounia Lakhdar; Ismaili, Leila; Bouharrou, Abdelhak; Hida, Moustapha

2011-01-01

Alors qu'elle est actuellement oubliée dans les pays développés, la syphilis congénitale se voit encore chez nous faute du dépistage anténatal. Ses formes cliniques sont polymorphes et orientent à tord vers d'autres pathologies surtout en période néonatale. Le diagnostic n'est donc pas toujours facile. La révélation d'une syphilis congénitale par une fracture spontanée est exceptionnellement décrite. Nous rapportons dans ce travail le cas d'un nourrisson de 2 mois ramené en consultation pour limitation douloureuse des mouvements du bras droit. Le diagnostic est évoqué sur les données radiologiques et confirmé par la sérologie syphilitique. Le traitement a reposé essentiellement sur l'administration de la pénicilline G avec une bonne évolution clinique. PMID:22384288

Cohesive zone modelling of wafer bonding and fracture: effect of patterning and toughness variations

NASA Astrophysics Data System (ADS)

Kubair, D. V.; Spearing, S. M.

2006-03-01

Direct wafer bonding has increasingly become popular in the manufacture of microelectromechanical systems and semiconductor microelectronics components. The success of the bonding process is controlled by variables such as wafer flatness and surface preparation. In order to understand the effects of these variables, spontaneous planar crack propagation simulations were performed using the spectral scheme in conjunction with a cohesive zone model. The fracture-toughness on the bond interface is varied to simulate the effect of surface roughness (nanotopography) and patterning. Our analysis indicated that the energetics of crack propagation is sensitive to the local surface property variations. The patterned wafers are tougher (well bonded) than the unpatterned ones of the same average fracture-toughness.

Self-Replicating Cracks: A Collaborative Fracture Mode in Thin Films

NASA Astrophysics Data System (ADS)

Marthelot, Joël; Roman, Benoît; Bico, José; Teisseire, Jérémie; Dalmas, Davy; Melo, Francisco

2014-08-01

Straight cracks are observed in thin coatings under residual tensile stress, resulting into the classical network pattern observed in china crockery, old paintings, or dry mud. Here, we present a novel fracture mechanism where delamination and propagation occur simultaneously, leading to the spontaneous self-replication of an initial template. Surprisingly, this mechanism is active below the standard critical tensile load for channel cracks and selects a robust interaction length scale on the order of 30 times the film thickness. Depending on triggering mechanisms, crescent alleys, spirals, or long bands are generated over a wide range of experimental parameters. We describe with a simple physical model, the selection of the fracture path and provide a configuration diagram displaying the different failure modes.

SURGICAL TREATMENT AND COMPLICATIONS OF PENILE FRACTURES

PubMed Central

Kulovac, Benjamin; Aganović, Damir; Junuzović, Dželaludin; Prcić, Alden; Hadžiosmanović, Osman; BazardžAnović, Mustafa; Hodžić, Harun

2007-01-01

Paper goal is to determine complications after urgent surgical treatment of patient with penile fractures, by using circumferential-degloving technique (degloving penile skin to root of penis). In period between 1998-2006 year, 23 patients have been treated as urgent cases with clinically proven penis fracture, age between 18 and 35. Patients were treated in 3 medical centers in Bosnia and Herzegovina(Sarajevo, Tuzla and Zenica). All 23 (100%) patients were injured during sexual intercourse. In the case of 20 (86,9%) patients partial rupture of corpus cavernosum was verified. Two (8,6%) patients had a complete rupture of urethra and it was primary sutured. In 22 cases (95,6%) spontaneous erection appeared, and in the case of 2 (8,6%) patients penile curvature was verified. Urgent surgical treatment is the best therapy choice, which enables preservation of erection in great number of cases in patients with penile fracture. PMID:17489766

Operative fixation of chest wall fractures: an underused procedure?

PubMed

Richardson, J David; Franklin, Glen A; Heffley, Susan; Seligson, David

2007-06-01

Chest wall fractures, including injuries to the ribs and sternum, usually heal spontaneously without specific treatment. However, a small subset of patients have fractures that produce overlying bone fragments that may produce severe pain, respiratory compromise, and, if untreated mechanically, result in nonunion. We performed open reduction and internal fixation on seven patients with multiple rib fractures-five in the initial hospitalization and two delayed--as well as 35 sternal fractures (19 immediate fixation and 16 delayed). Operative fixation was accomplished using titanium plates and screws in both groups of patients. All patients with rib fractures did well; there were no major complications or infections, and no plates required removal. Clinical results were excellent. There was one death in the sternal fracture group in a patient who was ventilator-dependent preoperatively and extubated himself in the early postoperative period. Otherwise, the results were excellent, with no complications occurring in this group. Three patients had their plates removed after boney union was achieved. No evidence of infection or nonunion occurred. The excellent results achieved in the subset of patients with severe chest wall deformities treated initially at our institution and those referred from outside suggest that operative fixation is a useful modality that is likely underused.

Fractographic Analysis of a Split Tooth Presenting Radiographically as a Horizontal Root Fracture in an Unrestored Mandibular Second Molar.

PubMed

Krishnan, Unni; Moule, Alex; Michael, Shaji; Swain, Michael

2018-02-01

Spontaneously catastrophic fracture of intact unrestored molar teeth is not common. Nevertheless, cracks do occur that progress apically, resulting in the complete splitting of the tooth and root. This report describes a catastrophic fracture that occurred in an unrestored mandibular second molar resulting in a previously unreported combination of a longitudinal and horizontal root fracture, appearing radiographically as a single horizontal root fracture. Tooth fragments were examined clinically, stereoscopically, and by scanning electron microscopy. Fractographic analysis was used to investigate the dynamics involved in fracture initiation, structural resistances encountered during progression of the fracture, and reasons for direction changes culminating in the unusual radiographic appearance. The uniqueness of this report is that it describes fractographic evidence of factors contributing to the initiation and progression of an in vivo crack. It shows fracture markings that are evidence of the energy dissipation mechanisms. The topographic location of these markings confirmed that cracks occur in vivo in stages with different rates of progression. This analysis helps to explain why split teeth are uncommon and highlights some of the multitude of factors that have to coincide for a tooth to catastrophically fracture. The report describes the mechanism of fracture and should stimulate clinicians and researchers to investigate cracking of teeth by undertaking fractographic analysis of extracted cracked teeth. Copyright © 2017 American Association of Endodontists. All rights reserved.

Disappearance of Intracranial Extradural Hematomas: Role of Diastatic Cranial Fracture and Intracranial Pressure - An Institutional Experience.

PubMed

Bhat, Abdul Rashid; Kirmani, Altaf Rehman; Wani, Mohammed Afzal

2018-01-01

The intracranial extradural hematoma (EDH) occupies space and creates a mass effect on the brain but the tenacious-adhesions of dura to the inner table of skull counters this effect. The intracranial pressure also pushes the hematoma back while it is held by dural tensile-force. The exploitation of a diastatic fracture, overlying an EDH, by the intracranial pressures to decompress a hematoma out of extradural space into subgaleal/subperiosteal space without surgical intervention. In a period of 15 years, a group of 11 patients among 729 EDHs were managed conservatively. The retrospective study of 11 EDH patients was conducted in the Department of Neurosurgery from January 2000 to December 2014 in 15 years. The statistical law of variance was used as applicable. Analysis of spontaneous disappearance of intracranial EDH among 11 patients revealed that only 1.5% (11/729) EDHs resolved conservatively. The most cases (63.6%) were children and the youngest being 9 months old. All the patients had a diastatic fracture overlying-EDH and were fully conscious. The cause of head injury in most was the fall from height. The hospital stay ranged from 2 to 4 days. All the patients had a good recovery at the time of discharging. The trial of the conservative or spontaneous disappearance of an EDH through a diastatic fracture into the subgaleal space is similar to burr-hole drainage without surgical intervention but depends upon the neurological status, the intracranial pressure of the patient, and the availability of all the modern neurosurgical gadgets.

Continuous pulse oximeter monitoring for inapparent hypoxemia after long bone fractures.

PubMed

Wong, Margaret Wan Nar; Tsui, Hon For; Yung, Shu Heng; Chan, Kai Ming; Cheng, Jack Chun Yiu

2004-02-01

Continuous pulse oximeter monitoring (CPOM) and daily intermittent arterial blood gas (ABG) were used to define the incidence, pattern, and severity of inapparent hypoxemia after long bone fractures. Twenty long bone fracture patients and 19 normal control patients were studied. CPOM, daily ABG, hypoxic symptoms, and features of fat embolism syndrome were monitored for 72 hours after fractures and after surgical interventions. CPOM trend curves showed that all fracture patients except one had recurrent desaturations below 90% Sao2 of varying duration and depth. The lowest Sao2 was down to 60% and the longest episode lasted for 1.47 hours. ABG analysis could not show the recurrent phenomena and never detected the corresponding desaturation episodes. Long bone fracture patients had more desaturation episodes, longer total desaturation duration, and larger total area under desaturation curves in both the postfracture and postoperative periods (p < 0.05). The mean Sao2 was significantly lower in the postfracture period. Although most patients remained asymptomatic and recovered spontaneously, two required transient oxygen therapy and one progressed to fat embolism syndrome. Inapparent hypoxia with profound desaturation is common after long bone fractures. CPOM of all patients admitted with long bone fractures is recommended for early detection. In patients who develop inapparent hypoxia, additional pulmonary insult should be avoided or undertaken with care and well timed.

Sites, frequencies, and causes of self-reported fractures in 9,720 rheumatoid arthritis patients: a large prospective observational cohort study in Japan.

PubMed

Ochi, Kensuke; Furuya, Takefumi; Ikari, Katsunori; Taniguchi, Atsuo; Yamanaka, Hisashi; Momohara, Shigeki

2013-01-01

Sites, frequencies, and causes of self-reported fractures in Japanese patients with rheumatoid arthritis (RA) were evaluated in a prospective, observational cohort study. The incidence and cause of fracture differ by anatomical site, sex, and age. These differences may be considered in establishing custom strategies for preventing fractures in RA patients in the future. The literature contains limited data describing the details of fractures at different skeletal sites in patients with RA. We evaluated the details of fractures in Japanese RA patients on the basis of our Institute of Rheumatology Rheumatoid Arthritis cohort study in 9,720 RA patients (82 % women; mean age, 56 years) who were enrolled from 2000 to 2010. The details of fractures were obtained through biannual patient self-report questionnaires. Over a mean duration of 5.2 years, 1,317 patients (13.5 %) reported 2,323 incident fractures comprising 563 (24.2 %) clinical vertebral fractures and 1,760 (75.8 %) nonvertebral fractures. Rib fractures were the most common fractures in men, followed by clinical vertebral and hip fractures; the most common fractures in women were clinical vertebral fractures, followed by rib, foot, and hip fractures. There was a significant difference between sexes in the rates of rib, clavicle, shoulder, and ankle fractures. Spontaneous event was the primary cause of clinical vertebral fracture (65.4 %), whereas falls were the primary cause of upper extremity (76.5 %) and lower extremity (57.8 %) fractures. Rates of clinical vertebral and hip fractures increased, while those of rib and foot fractures decreased with increasing age. Incidence of falls, as causes of nonvertebral fractures, also increased in older age groups. Our results suggest that the causes of fractures may differ depending on anatomical site and that prevention of falls may be the most effective way to reduce upper and lower extremity fractures, especially in older patients with RA.

Models of tibial fracture healing in normal and Nf1-deficient mice.

PubMed

Schindeler, Aaron; Morse, Alyson; Harry, Lorraine; Godfrey, Craig; Mikulec, Kathy; McDonald, Michelle; Gasser, Jürg A; Little, David G

2008-08-01

Delayed union and nonunion are common complications associated with tibial fractures, particularly in the distal tibia. Existing mouse tibial fracture models are typically closed and middiaphyseal, and thus poorly recapitulate the prevailing conditions following surgery on a human open distal tibial fracture. This report describes our development of two open tibial fracture models in the mouse, where the bone is broken either in the tibial midshaft (mid-diaphysis) or in the distal tibia. Fractures in the distal tibial model showed delayed repair compared to fractures in the tibial midshaft. These tibial fracture models were applied to both wild-type and Nf1-deficient (Nf1+/-) mice. Bone repair has been reported to be exceptionally problematic in human NF1 patients, and these patients can also spontaneously develop tibial nonunions (known as congenital pseudarthrosis of the tibia), which are recalcitrant to even vigorous intervention. pQCT analysis confirmed no fundamental differences in cortical or cancellous bone in Nf1-deficient mouse tibiae compared to wild-type mice. Although no difference in bone healing was seen in the tibial midshaft fracture model, the healing of distal tibial fractures was found to be impaired in Nf1+/- mice. The histological features associated with nonunited Nf1+/- fractures were variable, but included delayed cartilage removal, disproportionate fibrous invasion, insufficient new bone anabolism, and excessive catabolism. These findings imply that the pathology of tibial pseudarthrosis in human NF1 is complex and likely to be multifactorial.

Imaging of Spontaneous and Traumatic Cervical Artery Dissection : Comparison of Typical CT Angiographic Features.

PubMed

Sporns, Peter B; Niederstadt, Thomas; Heindel, Walter; Raschke, Michael J; Hartensuer, René; Dittrich, Ralf; Hanning, Uta

2018-01-26

Cervical artery dissection (CAD) is an important etiology of ischemic stroke and early recognition is vital to protect patients from the major complication of cerebral embolization by administration of anticoagulants. The etiology of arterial dissections differ and can be either spontaneous or traumatic. Even though the historical gold standard is still catheter angiography, recent studies suggest a good performance of computed tomography angiography (CTA) for detection of CAD. We conducted this research to evaluate the variety and frequency of possible imaging signs of spontaneous and traumatic CAD and to guide neuroradiologists' decision making. Retrospective review of the database of our multiple injured patients admitted to the Department of Trauma, Hand, and Reconstructive Surgery of the University Hospital Münster in Germany (a level 1 trauma center) for patients with traumatic CAD (tCAD) and of our stroke database (2008-2015) for patients with spontaneous CAD (sCAD) and CT/CTA on initial clinical work-up. All images were evaluated concerning specific and sensitive radiological features for dissection by two experienced neuroradiologists. Imaging features were compared between the two etiologies. This study included 145 patients (99 male, 46 female; 45 ± 18.8 years of age), consisting of 126 dissected arteries with a traumatic and 43 with spontaneous etiology. Intimal flaps were more frequently observed after traumatic etiology (58.1% tCADs, 6.9% sCADs; p < 0.001); additionally, multivessel dissections were much more frequent in trauma patients (3 sCADs, 21 tCADs) and only less than half (42%) of the patients with traumatic dissections showed cervical spine fractures. Neuroradiologists should be aware that intimal flaps and multivessel dissections are more common after a traumatic etiology. In addition, it seems important to conduct a CTA in a trauma setting, even if no cervical spine fracture is detected.

Anaesthesia of three young grey seals (Halichoerus grypus) for fracture repair

PubMed Central

2011-01-01

Three young grey seals (Halichoerus grypus) were presented separately for fracture repair to the veterinary teaching hospital of University College Dublin. The seals were premedicated with a combination of pethidine, midazolam and atropine; anaesthesia was induced with propofol via the front flipper vein and maintained with sevoflurane or isoflurane in oxygen. One of the seals did not breathe spontaneously after anaesthesia; a cardiac arrest, resulting in death, occurred after several hours of mechanical ventilation. Post-mortem examination revealed a severe lungworm infestation and parasitic pneumonia in this animal. The two other seals recovered uneventfully from anaesthesia. PMID:21777490

The Evaluation of Root Fracture with Cone Beam Computed Tomography (CBCT): An Epidemiological Study.

PubMed

Doğan, Mehmet-Sinan; Callea, Michele; Kusdhany, Lindawati S; Aras, Ahmet; Maharani, Diah-Ayu; Mandasari, Masita; Adiatman, Melissa; Yavuz, Izzet

2018-01-01

The aim of this study was evaluation of the cone-beam computed tomography (CBCT) image of 50 patients at the ages of 8-15 suspecting root fracture and root fracture occurred, exposed to dental traumatic. In additionally, this study was showed effect of crown fracture on root fracture healing. All of the individuals included in the study were obtained images with the cone-beam computed tomography range of 0,3 voxel and 8.9 seconds.(i-CAT®, Model 17-19, Imaging SciencesInternational, Hatfield, Pa USA).The information obtained from the history and CBCT images of patients were evaluated using chi-square test statistical method the mean and the distribution of the independent variables. 50 children, have been exposed to trauma, was detected root fracture injury in 97 teeth. Horizontal root fracture 63.9% of the 97 tooth, the oblique in 31.9%, both the horizontal and oblique in 1.03%, partial fracture in 2.06% ,and both horizontally and vertical in 1.03% was observed.The most affected teeth, respectively of, are the maxillary central incisor (41.23% left, right, 37.11%), maxillary left lateral incisor (9.27%), maxillary right lateral incisor (11.34%), and mandibular central incisor (1.03%). Crown fractures have negative effects on spontaneous healing of root fractures. CBCT are used selected as an alternative to with conventional radiography for diagnosis of root fractures. In particular, ıt's cross-sectional image is quite useful and has been provided more conveniences seeing the results of diagnosis and treatment for clinician. Key words: Root fracture, CBCT, Epidemiolog.

Osteoporosis in paediatric patients with spina bifida.

PubMed

Marreiros, Humberto; Marreiros, Humberto Filipe; Loff, Clara; Calado, Eulalia

2012-01-01

The prevalence and morbidity associated with osteoporosis and fractures in patients with spina bifida (SB) highlight the importance of osteoporosis prevention and treatment in early childhood; however, the issue has received little attention. The method for the selection of appropriate patients for drug treatment has not been clarified. To review the literature concerning fracture risks and low bone density in paediatric patients with SB. We looked for studies describing state-of-the-art treatments and for prevention of secondary osteoporosis. Articles were identified through a search in the electronic database (PUBMED) supplemented with reviews of the reference lists of selected papers. The main outcome measures were incidence of fractures and risk factors for fracture, an association between bone mineral density (BMD) and occurrence of fracture, risk factors of low BMD, and effects of pharmacological and non-pharmacological treatments on BMD and on the incidence of fractures. We considered as a secondary outcome the occurrence of fractures in relation to the mechanism of injury. Results indicated that patients with SB are at increased risk for fractures and low BMD. Risk factors that may predispose patients to fractures include higher levels of neurological involvement, non-ambulatory status, physical inactivity, hypercalciuria, higher body fat levels, contractures, and a previous spontaneous fracture. Limitations were observed in the number and quality of studies concerning osteoporosis prevention and treatment in paediatric patients with SB. The safety and efficiency of drugs to treat osteoporosis in adults have not been evaluated satisfactorily in children with SB.

Periosteal infusion of bupivacaine/morphine post sternal fracture: a new analgesic technique.

PubMed

Duncan, Michael A; McNicholas, Walter; O'Keeffe, Declan; O'Reilly, Maeve

2002-01-01

Sternal fracture pain is severe and is difficult to alleviate due to the forces acting on the chest wall during respiration. We describe a continuous infusion regional analgesic technique for pain due to sternal fracture. A 47-year-old woman presented with a spontaneous sternal fracture, precluding effective coughing. Diclofenac and increasing doses of opioids did not give adequate pain relief and led to opioid toxicity. Two brief periods of analgesia were achieved with deep subcutaneous infiltration of bupivacaine. An epidural catheter was positioned periosteally, and an infusion of bupivacaine was commenced at 5 mL/h, achieving long-lasting analgesia. The bupivacaine concentration was reduced in a stepwise fashion from 0.5% to 0.25% and was changed to levobupivacaine after 3 days. Adding morphine (5 mg/60 mL levobupivicaine) permitted a reduction in infusion rate. The catheter was removed after 14 days because a local infection developed that resolved uneventfully with antibiotic therapy. Continuous infusion of local anesthetic and opioid to a sternal fracture site using a periosteally positioned catheter led to successful analgesia and hence improved respiratory function. Clinicians should consider placing a periosteal catheter when pain associated with sternal fracture cannot be adequately controlled with conventional methods.

Rib fractures and death from deletion of osteoblast βcatenin in adult mice is rescued by corticosteroids.

PubMed

Duan, JinZhu; Lee, Yueh; Jania, Corey; Gong, Jucheng; Rojas, Mauricio; Burk, Laurel; Willis, Monte; Homeister, Jonathon; Tilley, Stephen; Rubin, Janet; Deb, Arjun

2013-01-01

Ribs are primarily made of cortical bone and are necessary for chest expansion and ventilation. Rib fractures represent the most common type of non-traumatic fractures in the elderly yet few studies have focused on the biology of rib fragility. Here, we show that deletion of βcatenin in Col1a2 expressing osteoblasts of adult mice leads to aggressive osteoclastogenesis with increased serum levels of the osteoclastogenic cytokine RANKL, extensive rib resorption, multiple spontaneous rib fractures and chest wall deformities. Within days of osteoblast specific βcatenin deletion, animals die from respiratory failure with a vanishing rib cage that is unable to sustain ventilation. Increased bone resorption is also observed in the vertebrae and femur. Treatment with the bisphosphonate pamidronate delayed but did not prevent death or associated rib fractures. In contrast, administration of the glucocorticoid dexamethasone decreased serum RANKL and slowed osteoclastogenesis. Dexamethasone preserved rib structure, prevented respiratory compromise and strikingly increased survival. Our findings provide a novel model of accelerated osteoclastogenesis, where deletion of osteoblast βcatenin in adults leads to rapid development of destructive rib fractures. We demonstrate the role of βcatenin dependent mechanisms in rib fractures and suggest that glucocorticoids, by suppressing RANKL, may have a role in treating bone loss due to aggressive osteoclastogenesis.

Rib Fractures and Death from Deletion of Osteoblast βcatenin in Adult Mice Is Rescued by Corticosteroids

PubMed Central

Duan, JinZhu; Lee, Yueh; Jania, Corey; Gong, Jucheng; Rojas, Mauricio; Burk, Laurel; Willis, Monte; Homeister, Jonathon; Tilley, Stephen; Rubin, Janet; Deb, Arjun

2013-01-01

Ribs are primarily made of cortical bone and are necessary for chest expansion and ventilation. Rib fractures represent the most common type of non-traumatic fractures in the elderly yet few studies have focused on the biology of rib fragility. Here, we show that deletion of βcatenin in Col1a2 expressing osteoblasts of adult mice leads to aggressive osteoclastogenesis with increased serum levels of the osteoclastogenic cytokine RANKL, extensive rib resorption, multiple spontaneous rib fractures and chest wall deformities. Within days of osteoblast specific βcatenin deletion, animals die from respiratory failure with a vanishing rib cage that is unable to sustain ventilation. Increased bone resorption is also observed in the vertebrae and femur. Treatment with the bisphosphonate pamidronate delayed but did not prevent death or associated rib fractures. In contrast, administration of the glucocorticoid dexamethasone decreased serum RANKL and slowed osteoclastogenesis. Dexamethasone preserved rib structure, prevented respiratory compromise and strikingly increased survival. Our findings provide a novel model of accelerated osteoclastogenesis, where deletion of osteoblast βcatenin in adults leads to rapid development of destructive rib fractures. We demonstrate the role of βcatenin dependent mechanisms in rib fractures and suggest that glucocorticoids, by suppressing RANKL, may have a role in treating bone loss due to aggressive osteoclastogenesis. PMID:23393600

Disappearance of Intracranial Extradural Hematomas: Role of Diastatic Cranial Fracture and Intracranial Pressure - An Institutional Experience

PubMed Central

Bhat, Abdul Rashid; Kirmani, Altaf Rehman; Wani, Mohammed Afzal

2018-01-01

Context: The intracranial extradural hematoma (EDH) occupies space and creates a mass effect on the brain but the tenacious-adhesions of dura to the inner table of skull counters this effect. The intracranial pressure also pushes the hematoma back while it is held by dural tensile-force. Aims: The exploitation of a diastatic fracture, overlying an EDH, by the intracranial pressures to decompress a hematoma out of extradural space into subgaleal/subperiosteal space without surgical intervention. Settings and Design: In a period of 15 years, a group of 11 patients among 729 EDHs were managed conservatively. Materials and Methods: The retrospective study of 11 EDH patients was conducted in the Department of Neurosurgery from January 2000 to December 2014 in 15 years. Statistical Analysis Used: The statistical law of variance was used as applicable. Results: Analysis of spontaneous disappearance of intracranial EDH among 11 patients revealed that only 1.5% (11/729) EDHs resolved conservatively. The most cases (63.6%) were children and the youngest being 9 months old. All the patients had a diastatic fracture overlying-EDH and were fully conscious. The cause of head injury in most was the fall from height. The hospital stay ranged from 2 to 4 days. All the patients had a good recovery at the time of discharging. Conclusion: The trial of the conservative or spontaneous disappearance of an EDH through a diastatic fracture into the subgaleal space is similar to burr-hole drainage without surgical intervention but depends upon the neurological status, the intracranial pressure of the patient, and the availability of all the modern neurosurgical gadgets. PMID:29682037

PHOSPHO1 is essential for mechanically competent mineralization and the avoidance of spontaneous fractures

PubMed Central

Huesa, Carmen; Yadav, Manisha C.; Finnilä, Mikko A.J.; Goodyear, Simon R.; Robins, Simon P.; Tanner, K. Elizabeth; Aspden, Richard M.; Millán, José Luis; Farquharson, Colin

2011-01-01

Phosphatases are essential for the mineralization of the extracellular matrix within the skeleton. Their precise identities and functions however remain unclear. PHOSPHO1 is a phosphoethanolamine/phosphocholine phosphatase involved in the generation of inorganic phosphate for bone mineralization. It is highly expressed at sites of mineralization in bone and cartilage. The bones of Phospho1−/− mice are hypomineralized, bowed and present with spontaneous greenstick fractures at birth. In this study we show that PHOSPHO1 is essential for mechanically competent mineralization that is able to withstand habitual load. Long bones from Phospho1−/− mice did not fracture during 3- point bending but deformed plastically. With dynamic loading nanoindentation the elastic modulus and hardness of Phospho1−/− tibiae were significantly lower than wild-type tibia. Raman microscopy revealed significantly lower mineral:matrix ratios and lower carbonate substitutions in Phospho1−/− tibia. The altered dihydroxylysinonorleucine/hydroxyllysinonorleucine and pyridoline/deoxypyridinoline collagen crosslink ratios indicated possible changes in lysyl hydroxylase-1 activity and/or bone mineralization status. The bone formation and resorption markers, N-terminal propeptide and C-terminal telopeptide of Type I collagen, were both increased in Phospho1−/− mice and this we associated with increased bone remodelling during fracture repair or an attempt to remodel a mechanically competent bone capable of withstanding physiological load. In summary these data indicate that Phospho1−/− bones are hypomineralized and, consequently, are softer and more flexible. An inability to withstand physiological loading may explain the deformations noted. We hypothesize that this phenotype is due to the reduced availability of inorganic phosphate to form hydroxyapatite during mineralization, creating an undermineralized yet active bone. PMID:21272676

Spontaneous bilateral fracture of patella.

PubMed

Moretti, Biagio; Speciale, Domenico; Garofalo, Raffaele; Moretti, Lorenzo; Patella, Silvio; Patella, Vittorio

2008-03-01

Bilateral patellae fractures represent a rare entity, accounting for approximately 2.9% of all lesions interesting in this anatomical district. In most cases found in the published work, they are described as stress fractures or as complications of chronic diseases such as osteoporosis, renal failure and secondary hyperparathyroidism. Although many pathogenetic mechanisms have been supposed, none have been proved for certain. Insufficiency fractures of the patellae are rare events and no data has been published on their incidence. We present a case of bilateral fracture of the patellae due to an indirect trauma occurring in an 85-year-old patient affected by Parkinson's disease, osteoporosis and diffuse degenerative osteoarthritis. X-ray of the knees (anteroposterior and lateral) and magnetic resonance imaging evaluation confirmed the fractures. The patient was treated conservatively. She had a good result, returning to her previous autonomous ambulation. This case is unusual because there was no direct trauma to the knees because of bilaterality, but confirmed previous observations about insufficiency fractures of patellae in the presence of comorbidity. Insufficiency fractures of patellae can be an insidious condition in elderly people. Prepatellar pain, a common symptom in the relapse phase of degenerative arthritis of the knee, should not be underestimated, particularly in patients with diseases influencing metabolism of bone and with an elevated risk of fall. A periodical clinical and instrumental follow up should be done in these patient. Moreover, we underline the necessity of a multidisciplinary approach.

A Novel Approach for Treatment of Acetabular Fractures

PubMed Central

Xue, Zichao; Qin, Hui; Ding, Haoliang; An, Zhiquan

2016-01-01

Background There is no single approach that provides adequate exposure for treatment of all types of acetabular fractures. We describe our experience with an easier, relatively less invasive pubic symphysis approach (PSA) for the treatment of acetabular fractures. Material/Methods Between March 2011 and March 2012, fifteen patients with acetabular fracture underwent surgery using the PSA technique. Fracture reduction and treatment outcomes were assessed by clinical and radiological examination. Operation time, intraoperative blood loss and postoperative complications were documented. Results Mean operative time was 222±78 minutes. Average blood loss was 993±361 mL. Anatomical reduction was achieved in all patients. Minimum follow-up period was 31 months. Postoperative hypoesthesia in the area of innervation of the lateral femoral cutaneous nerve was reported in one patient, with spontaneous recovery at one month after surgery. No complications were reported during the follow-up period. At the most recent follow up, clinical outcomes were graded as “excellent” in six patients, “good” in eight patients and “fair” in one patient based on the modified Merle d’Aubigné-Postel score. Conclusions PSA appears to be a timesaving and safe approach for treatment of acetabular fractures that affords good visual access and allows for excellent fracture reduction. Our preliminary results revealed a much lower incidence of complications than traditional approaches, suggesting PSA is an alternative for treatment of acetabular fractures. PMID:27734825

Discordance between the degree of osteopenia and the prevalence of spontaneous vertebral fractures in Crohn's disease.

PubMed

Stockbrügger, R W; Schoon, E J; Bollani, S; Mills, P R; Israeli, E; Landgraf, L; Felsenberg, D; Ljunghall, S; Nygard, G; Persson, T; Graffner, H; Bianchi Porro, G; Ferguson, A

2002-08-01

A high prevalence of osteoporosis has been noted in Crohn's disease, but data about fractures are scarce. The relationship between low bone mineral density and the prevalence of vertebral fractures was studied in 271 patients with ileo-caecal Crohn's disease in a large European/Israeli study. One hundred and eighty-one currently steroid-free patients with active Crohn's disease (98 completely steroid-naive) and 90 steroid-dependent patients with inactive or quiescent Crohn's disease were investigated by dual X-ray absorptiometry scan of the lumbar spine, a standardized posterior/anterior and lateral X-ray of the thoracic and lumbar spine, and an assessment of potential risk factors for osteoporosis. Thirty-nine asymptomatic fractures were seen in 25 of 179 steroid-free patients (14.0%; 27 wedge, 12 concavity), and 17 fractures were seen in 13 of 89 steroid-dependent patients (14.6%; 14 wedge, three concavity). The prevalence of fractures in steroid-naive patients was 12.4%. The average bone mineral density, expressed as the T-score, of patients with fractures was not significantly different from that of those without fractures (-0.759 vs. -0.837; P=0.73); 55% of patients with fractures had a normal T-score. The bone mineral density was negatively correlated with lifetime steroids, but not with previous bowel resection or current disease activity. The fracture rate was not correlated with the bone mineral density (P=0.73) or lifetime steroid dose (P=0.83); in women, but not in men, the fracture rate was correlated with age (P=0.009). The lack of correlation between the prevalence of fractures on the one hand and the bone mineral density and lifetime steroid dose on the other necessitates new hypotheses for the pathogenesis of the former.

The Evaluation of Root Fracture with Cone Beam Computed Tomography (CBCT): An Epidemiological Study

PubMed Central

Doğan, Mehmet-Sinan; Callea, Michele; Kusdhany, Lindawati S.; Aras, Ahmet; Maharani, Diah-Ayu; Mandasari, Masita; Adiatman, Melissa

2018-01-01

Background The aim of this study was evaluation of the cone-beam computed tomography (CBCT) image of 50 patients at the ages of 8-15 suspecting root fracture and root fracture occurred, exposed to dental traumatic. In additionally, this study was showed effect of crown fracture on root fracture healing. Material and Methods All of the individuals included in the study were obtained images with the cone-beam computed tomography range of 0,3 voxel and 8.9 seconds.(i-CAT®, Model 17-19, Imaging SciencesInternational, Hatfield, Pa USA).The information obtained from the history and CBCT images of patients were evaluated using chi-square test statistical method the mean and the distribution of the independent variables. Results 50 children, have been exposed to trauma, was detected root fracture injury in 97 teeth. Horizontal root fracture 63.9% of the 97 tooth, the oblique in 31.9%, both the horizontal and oblique in 1.03%, partial fracture in 2.06% ,and both horizontally and vertical in 1.03% was observed.The most affected teeth, respectively of, are the maxillary central incisor (41.23% left, right, 37.11%), maxillary left lateral incisor (9.27%), maxillary right lateral incisor (11.34%), and mandibular central incisor (1.03%). Conclusions Crown fractures have negative effects on spontaneous healing of root fractures. CBCT are used selected as an alternative to with conventional radiography for diagnosis of root fractures. In particular, ıt’s cross-sectional image is quite useful and has been provided more conveniences seeing the results of diagnosis and treatment for clinician. Key words:Root fracture, CBCT, Epidemiolog. PMID:29670714

Permeability evolution of shale during spontaneous imbibition

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

Chakraborty, N.; Karpyn, Z. T.; Liu, S.

Shales have small pore and throat sizes ranging from nano to micron scales, low porosity and limited permeability. The poor permeability and complex pore connectivity of shales pose technical challenges to (a) understanding flow and transport mechanisms in such systems and, (b) in predicting permeability changes under dynamic saturation conditions. This paper presents quantitative experimental evidence of the migration of water through a generic shale core plug using micro CT imaging. In addition, in-situ measurements of gas permeability were performed during counter-current spontaneous imbibition of water in nano-darcy permeability Marcellus and Haynesville core plugs. It was seen that water blocksmore » severely reduced the effective permeability of the core plugs, leading to losses of up to 99.5% of the initial permeability in experiments lasting 30 days. There was also evidence of clay swelling which further hindered gas flow. When results from this study were compared with similar counter-current gas permeability experiments reported in the literature, the initial (base) permeability of the rock was found to be a key factor in determining the time evolution of effective gas permeability during spontaneous imbibition. With time, a recovery of effective permeability was seen in the higher permeability rocks, while becoming progressively detrimental and irreversible in tighter rocks. Finally, these results suggest that matrix permeability of ultra-tight rocks is susceptible to water damage following hydraulic fracturing stimulation and, while shut-in/soaking time helps clearing-up fractures from resident fluid, its effect on the adjacent matrix permeability could be detrimental.« less

Permeability evolution of shale during spontaneous imbibition

DOE PAGES

Chakraborty, N.; Karpyn, Z. T.; Liu, S.; ...

2017-01-05

Shales have small pore and throat sizes ranging from nano to micron scales, low porosity and limited permeability. The poor permeability and complex pore connectivity of shales pose technical challenges to (a) understanding flow and transport mechanisms in such systems and, (b) in predicting permeability changes under dynamic saturation conditions. This paper presents quantitative experimental evidence of the migration of water through a generic shale core plug using micro CT imaging. In addition, in-situ measurements of gas permeability were performed during counter-current spontaneous imbibition of water in nano-darcy permeability Marcellus and Haynesville core plugs. It was seen that water blocksmore » severely reduced the effective permeability of the core plugs, leading to losses of up to 99.5% of the initial permeability in experiments lasting 30 days. There was also evidence of clay swelling which further hindered gas flow. When results from this study were compared with similar counter-current gas permeability experiments reported in the literature, the initial (base) permeability of the rock was found to be a key factor in determining the time evolution of effective gas permeability during spontaneous imbibition. With time, a recovery of effective permeability was seen in the higher permeability rocks, while becoming progressively detrimental and irreversible in tighter rocks. Finally, these results suggest that matrix permeability of ultra-tight rocks is susceptible to water damage following hydraulic fracturing stimulation and, while shut-in/soaking time helps clearing-up fractures from resident fluid, its effect on the adjacent matrix permeability could be detrimental.« less

Orthopedic surgery and bone fracture pain are both significantly attenuated by sustained blockade of nerve growth factor

PubMed Central

Majuta, Lisa A.; Longo, Geraldine; Fealk, Michelle N.; McCaffrey, Gwen; Mantyh, Patrick W.

2015-01-01

The number of patients suffering from postoperative pain due to orthopedic surgery and bone fracture is projected to dramatically increase because the human life span, weight, and involvement in high-activity sports continue to rise worldwide. Joint replacement or bone fracture frequently results in skeletal pain that needs to be adequately controlled for the patient to fully participate in needed physical rehabilitation. Currently, the 2 major therapies used to control skeletal pain are nonsteroidal anti-inflammatory drugs and opiates, both of which have significant unwanted side effects. To assess the efficacy of novel therapies, mouse models of orthopedic and fracture pain were developed and evaluated here. These models, orthopedic surgery pain and bone fracture pain, resulted in skeletal pain–related behaviors that lasted 3 weeks and 8 to 10 weeks, respectively. These skeletal pain behaviors included spontaneous and palpation-induced nocifensive behaviors, dynamic weight bearing, limb use, and voluntary mechanical loading of the injured hind limb. Administration of anti–nerve growth factor before orthopedic surgery or after bone fracture attenuated skeletal pain behaviors by 40% to 70% depending on the end point being assessed. These data suggest that nerve growth factor is involved in driving pain due to orthopedic surgery or bone fracture. These animal models may be useful in developing an understanding of the mechanisms that drive postoperative orthopedic and bone fracture pain and the development of novel therapies to treat these skeletal pains. PMID:25599311

Spontaneous C1 anterior arch fracture as a postoperative complication of foramen magnum decompression for Chiari malformation type 1

PubMed Central

Hirano, Yoshitaka; Sugawara, Atsushi; Mizuno, Junichi; Takeda, Masaaki; Watanabe, Kazuo; Ogasawara, Kuniaki

2011-01-01

Background: C1 fracture accounts for 2% of all spinal column injuries and 10% of cervical spine fractures, and is most frequently caused by motor vehicle accidents and falls. We present a rare case of C1 anterior arch fracture following standard foramen magnum decompression for Chiari malformation type 1. Case Description: A 63-year-old man underwent standard foramen magnum decompression (suboccipital craniectomy and C1 laminectomy) under a diagnosis of Chiari malformation type 1 with syringomyelia in June 2009. The postoperative course was uneventful until the patient noticed progressive posterior cervical pain 5 months after the operation. Computed tomography of the upper cervical spine obtained 7 months after the operation revealed left C1 anterior arch fracture. The patient was referred to our hospital at the end of January 2010 and C1–C2 posterior fusion with C1 lateral mass screws and C2 laminar screws was carried out in March 2010. Complete pain relief was achieved immediately after the second operation, and the patient resumed his daily activities. Conclusion: Anterior atlas fracture following foramen magnum decompression for Chiari malformation type 1 is very rare, but C1 laminectomy carries the risk of anterior arch fracture. Neurosurgeons should recognize that fracture of the atlas, which commonly results from an axial loading force, can occur in the postoperative period in patients with Chiari malformation. PMID:22059133

Cold Cracking During Direct-Chill Casting

NASA Astrophysics Data System (ADS)

Eskin, D. G.; Lalpoor, M.; Katgerman, L.

Cold cracking phenomenon is the least studied, yet very important defect occurring during direct chill casting. The spontaneous nature of this defect makes its systematic study almost impossible, and the computer simulation of the thermomechanical behavior of the ingot during its cooling after the end of solidification requires constitutive parameters of high-strength aluminum alloys in the as-cast condition, which are not readily available. In this paper we describe constitutive behavior of high strength 7xxx series aluminum alloys in the as-cast condition based on experimentally measured tensile properties at different strain rates and temperatures, plane strain fracture toughness at different temperatures, and thermal contraction. In addition, fracture and structure of the specimens and real cold-cracked billets are examined. As a result a fracture-mechanics-based criterion of cold cracking is suggested based on the critical crack length, and is validated upon pilot-scale billet casting.

Reconstruction of the pelvic brim and its role in the reduction accuracy of displaced T-shaped acetabular fracture.

PubMed

Harnroongroj, T; Asavamongkolkul, A; Chareancholvanich, K

2000-05-01

Open reduction of the displaced T-shaped acetabular fracture has a problem of accuracy of the fracture reduction. This study was carried out to demonstrate that the reconstruction of the pelvic brim by approaching the pubo-acetabular fragment plays a role in the accuracy of the reduction of displaced T-shaped acetabular fractures. From 1975 to 1990, a retrospective study was carried out of 22 patients who sustained a displaced T-shaped acetabular fracture. The patients were operated on by open reduction and internal fixation of the ischio-acetabular fragment to the posterior column without restoration of the pelvic brim. Radiographs of the pelvis were reviewed. The result showed that there was displacement of the pubo-acetabular fragment including the medial wall in all cases. As the result of this study, a prospective study between 1990 and 1997 was carried out of 15 patients who sustained displaced T-shaped acetabular fractures including 3 cases with medial displacement of the femoral head. The pubo-acetabular fragment was anatomically reduced and fixed to the anterior column of the acetabulumn as the first approach to restore a disrupted pelvic brim. There, patterns of the acetabular fracture were subsequently re-evaluated especially the ischio-acetabular fragment including the position of the femoral head by using an intraoperative portable X-ray technique. The stability of the hip joint was assessed by hip flexion. The intraoperative radiograph appearances of the ischio-acetabular fragment were visually confirmed by a second surgical exposure. The results showed that the intraoperative radiographs gave spontaneous reduction of the ischio-acetabular fragment in all patients except one. There was a reduction of the displaced femoral head into the hip socket in the three patients. The hip joints were stable in all patients. The second surgical exposure showed that there was good spontaneous reduction of the ischio-acetabular fragment to the posterior column by ligamentotaxis in 14 patients. Therefore, it is not necessary to address the ischio-acetabular fragment. In the exceptional case, the ischio-acetabular fragment was displaced as a free bone which could not be reduced by ligamentotaxis. However, reduction and internal fixation of the ischio-acetabular fragment to the posterior column for complete re-application of the hip joint onto the pelvic ring of this case was facilitated. Postoperative 2 year and 5 year follow-up showed that the fracture had healed without heterotrophic ossification or premature osteoarthrosis of the hip joint. The exceptional case had a broken plate at the anterior column of the acetabulum. Hip function was evaluated clinically using Merle D' Aubigne's hip score. All patients had a "very good score". The study showed that reconstruction of the pelvic brim by anatomical reduction and fixation of the pubo-acetabular fragment to the anterior column plays an important role in the accuracy of fracture reduction of a displaced T-shaped acetabular fracture.

Triple Junction Reorganizations: A Mechanism for the Initiation of the Great Pacific Fractures Zones

NASA Astrophysics Data System (ADS)

Pockalny, R. A.; Larson, R. L.; Grindlay, N. R.

2001-12-01

There are two general explanations for the initiation of oceanic transform faults that eventually evolve into fracture zones: transforms inherited from continental break-up and transforms acquired in response to a change in plate motions. These models are sufficient to explain the fracture zones in oceans formed by continental break-up. However, neither model accounts for the initiation of the large-offset, great Pacific fracture zones that characterized the Pacific-Farallon plate boundary prior to 25 Ma. Primarily, these models are unable to explain why the initial age of these fracture zones becomes progressively younger from the Mendocino fracture zone (\\~{ } 160 Ma) southward down to the Resolution FZ (\\~{ }84 Ma). We propose a new transform initiation mechanism for the great Pacific fracture zones, which is intimately tied to tectonic processes at triple junctions and directly related to the growth of the Pacific Plate. Recently acquired multibeam bathymetry and marine geophysics data collected along Pandora's Escarpment in the southwestern Pacific have identified the escarpment as the trace of the Pacific-Farallon-Phoenix triple junction on the Pacific Plate. Regional changes in the trend of the triple junction trace between 84-121 Ma roughly coincide with the initiation of the Marquesas, Austral and Resolution fracture zones. Bathymetry and backscatter data from the projected intersections of these fracture zones with the triple junction trace identify several anomalous structures that suggest tectonic reorganizations of the triple junction. We believe this reorganization created the initial transform fault(s) that ultimately became the large-offset, great Pacific fracture zones. Several possible mechanisms for initiating the transform faults are explored including microplate formation, ridge-tip propagation, and spontaneous transform fault formation.

Management of distal humeral coronal shear fractures

PubMed Central

Yari, Shahram S; Bowers, Nathan L; Craig, Miguel A; Reichel, Lee M

2015-01-01

Coronal shear fractures of the distal humerus are rare, complex fractures that can be technically challenging to manage. They usually result from a low-energy fall and direct compression of the distal humerus by the radial head in a hyper-extended or semi-flexed elbow or from spontaneous reduction of a posterolateral subluxation or dislocation. Due to the small number of soft tissue attachments at this site, almost all of these fractures are displaced. The incidence of distal humeral coronal shear fractures is higher among women because of the higher rate of osteoporosis in women and the difference in carrying angle between men and women. Distal humeral coronal shear fractures may occur in isolation, may be part of a complex elbow injury, or may be associated with injuries proximal or distal to the elbow. An associated lateral collateral ligament injury is seen in up to 40% and an associated radial head fracture is seen in up to 30% of these fractures. Given the complex nature of distal humeral coronal shear fractures, there is preference for operative management. Operative fixation leads to stable anatomic reduction, restores articular congruity, and allows initiation of early range-of-motion movements in the majority of cases. Several surgical exposure and fixation techniques are available to reconstruct the articular surface following distal humeral coronal shear fractures. The lateral extensile approach and fixation with countersunk headless compression screws placed in an anterior-to-posterior fashion are commonly used. We have found a two-incision approach (direct anterior and lateral) that results in less soft tissue dissection and better outcomes than the lateral extensile approach in our experience. Stiffness, pain, articular incongruity, arthritis, and ulnohumeral instability may result if reduction is non-anatomic or if fixation fails. PMID:25984515

Dilemmas in distinguishing between tumor and the posttraumatic lesion with surgical or pathologic correlation.

PubMed

Walker, Eric; Brian, Pam; Longo, Victor; Fox, Edward J; Frauenhoffer, Elizabeth E; Murphey, Mark

2013-07-01

This article discusses the most common diagnostic dilemmas when trying to distinguish between tumor and sports injury or other trauma. Bone tumors frequently occur in the same young active patients who experience sports injuries. If the pain persists longer than expected, imaging studies should be obtained to prevent a delay in diagnosis or an inappropriate arthroscopy. A history of spontaneous fracture or a fracture after minor trauma should raise suspicion for underlying lesion as the cause. Occasionally necrosis and/or hemorrhage within a soft tissue sarcoma is so extensive that only a small cuff of viable tumor tissue is present. Copyright © 2013 Elsevier Inc. All rights reserved.

Massive Intrapelvic Hematoma after a Pubic Ramus Fracture in an Osteoporotic Patient

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

Haruki, Funao, E-mail: hfunao@yahoo.co.jp; Takahiro, Koyanagi

2016-03-24

An 88-year-old female presented with a left thigh pain and dysuria. She visited our hospital 2 week after she noticed her symptoms. She stated that she might have a low-energy fall, but she could not identify the exact onset. Her radiograph of the pelvis (Figure 1) showed displaced left pubic ramus fracture. Her computed tomographic scanning of the pelvis (Figure 2) showed massive intrapelvic hematoma (axial size, 11 cm by 5 cm) around the fracture site, although she did not use any anticoagulants. Because her bone mineral density was 0.357 g/cm{sup 2}, and T score was -4.8 SD, she startedmore » a bisphosphonate therapy. She received a bed-rest physical therapy for 6 weeks, and the hematoma regressed spontaneously. She started full weight bearing after 6 weeks, and walked by a walker after 8 weeks. Although it is extremely rare to develop massive chronic intra-pelvic hematoma after a lowenergy pubic ramus fracture without any use of anticoagulants, it may occur in elderly and severely osteoporotic patient.« less

[Growth behaviour after fractures of the proximal radius: differences to the rest of the skeleton].

PubMed

Hell, A K; von Laer, L

2014-12-01

Fractures of the proximal end of the radius in the growth phase have three characteristics: the head of the radius articulates with two joint partners and is therefore indispensable for an undisturbed function of the elbow. The blood supply of the proximal end of the radius is via periosteal vessels in the sense of a terminal circulation which makes it extremely vulnerable. Severe trauma caused either by accidents or treatment, can result in partial or complete necrosis with deformity of the head and neck region of the radius. Radioulnar synostosis and chronic epiphysiolysis are irreversible complications which can occur after excessive physiotherapy. Despite a low potency growth plate, in young patients the proximal end of the radius shows an enormous spontaneous correction of dislocations. Side to side shifts, however, will not be remodeled. Therapy should be as atraumatic as possible. Due to the blood supply situation, with the appropriate indications the spontaneous correction and a brief period of immobilization without physiotherapy should be integrated into the therapy concept. If an operation is necessary, repeated traumatic repositioning maneuvers should be avoided and in case of doubt closed or careful open repositioning can be achieved with intramedullary nailing. In order to take the special characteristics of the proximal radius into consideration, the vulnerability and correction potential must be weighed up against each other. Therapy must be as atraumatic as possible. The spontaneous correction potential should be integrated into the primary therapy without overestimating this potential with respect to the extent and age of the patient.

Simultaneous Bilateral Femur Neck Fracture in A Young Adult with Chronic Renal Failure- A Case Report and Review of Literature.

PubMed

V, Sathyanarayana; Patel, Maulik Tulsibhai; S, Raghavan; D, Naresh

2015-01-01

Pathological bilateral femoral neck fracture due to renal osteodystrophy is rare. This is a report of a chronic renal failure patient who had sustained bilateral intra-capsular displaced fracture neck of femur following an episode of convulsion and the difficulties encountered in early diagnosis and treatment. The pathophysiology of renal osteodystrophy and the treatment of hip fractures in patients with renal failure are also discussed. A 23 years old male patient admitted with h/o dysuria, pyuria and loss of appetite since 3 months. He was a known case of chronic renal failure and reflux nephropathy. On investigating, patient's renal parameters were high and he was started with haemodialysis. The next day patient had c/o bilateral hip pain and inability to move bilateral lower limbs following an episode of seizure. Radiograph of pelvis showed vertical sub capital fractures of bilateral neck of femur. In this patient, considering his age, general condition & prognosis, an elective surgery in the form of bilateral uncemented modular bipolar hemiarthroplasty was done. Overall risk of hip fracture among patients with chronic renal failure is considerably higher than in the general population, independent of age and gender. Simultaneous spontaneous bilateral fractures of the femoral neck are rare and a delayed diagnosis is usual. The study of etiological factors of these fractures is essential to guide us in choosing the treatment of choice. Obviously patient's age, life expectancy as well as renal co morbidity has an influence over deciding treatment and outcome.

Thricho-rhino-phalangeal syndrome and severe osteoporosis: a rare association or a feature? An effective therapeutic approach with biphosphonates.

PubMed

Macchiaiolo, M; Mennini, M; Digilio, M C; Buonuomo, P S; Lepri, F R; Gnazzo, M; Grandin, A; Angioni, A; Bartuli, A

2014-03-01

Trichorhinophalangeal syndrome (TRPS) is a rare, autosomal dominant malformation syndrome characterized by hair, craniofacial and skeletal abnormalities, skin laxity, deformation of phalanges and anomalies of pelvis, femurs, and tibias. Three subtypes have been described: TRPS I, caused by mutations in TRPS1 gene on chromosome 8; TRPS II, a microdeletion syndrome affecting the TRPS1 and EXT1 genes; and TRPS III, a form with severe brachydactyly, due to short metacarpals, and severe short stature, but without exostoses. We present the case of a 7-year-old boy, affected by TRPS with a severe osteoporosis and several spontaneous bone fractures, an association described only once in the literature, successfully treated with biphosphonates. Bone mineral density (BMD) at dual-energy X-ray Absorptiometry (DXA) was of 0.331 g/cm(2) at lumbar spine with. He had four spontaneous femoral fractures in a year, and for this reason he was been operated for positioning intramedullary osteosynthesis and orthopedic supports. Due to the severity of the clinical and radiological pattern it was established, after approval of the Ethical Committee, to begin off-label therapy with infusions of neridronate at a dose of 2 mg/kg IV every 3 months. The treatment was, in this patient, effective both in terms of clinical (absence of new fractures) and mineralomethric (+45% BMD ath the lumbar level). We therefore suggest that treatment with biphosponates can be taken in account as a possible therapeutic option in case of bone fragility in patients with TRPSI. © 2013 Wiley Periodicals, Inc.

Microarray profiling of diaphyseal bone of rats suffering from hypervitaminosis A.

PubMed

Lind, Thomas; Hu, Lijuan; Lind, P Monica; Sugars, Rachael; Andersson, Göran; Jacobson, Annica; Melhus, Håkan

2012-03-01

Vitamin A is the only known compound that produces spontaneous fractures in rats. In an effort to resolve the molecular mechanism behind this effect, we fed young male rats high doses of vitamin A and performed microarray analysis of diaphyseal bone with and without marrow after 1 week, i.e., just before the first fractures appeared. Of the differentially expressed genes in cortical bone, including marrow, 98% were upregulated. In contrast, hypervitaminotic cortical bone without marrow showed reduced expression of 37% of differentially expressed genes. Gene ontology (GO) analysis revealed that only samples containing bone marrow were associated with a GO term, which principally represented extracellular matrix. This is consistent with the histological findings of increased endosteal/marrow osteoblast number. Fourteen genes, including Cyp26b1, which is known to be upregulated by vitamin A, were selected and verified by real-time PCR. In addition, immunohistochemical staining of bone sections confirmed that the bone-specific molecule osteoadherin was upregulated. Further analysis of the major gene-expression changes revealed apparent augmented Wnt signaling in the sample containing bone marrow but reduced Wnt signaling in cortical bone. Moreover, induced expression of hypoxia-associated genes was found only in samples containing bone marrow. Together, these results highlight the importance of compartment-specific analysis of bone and corroborate previous observations of compartment-specific effects of vitamin A, with reduced activity in cortical bone but increased activity in the endosteal/marrow compartment. We specifically identify potential key osteoblast-, Wnt signaling-, and hypoxia-associated genes in the processes leading to spontaneous fractures.

Detecting dynamic causal inference in nonlinear two-phase fracture flow

NASA Astrophysics Data System (ADS)

Faybishenko, Boris

2017-08-01

Identifying dynamic causal inference involved in flow and transport processes in complex fractured-porous media is generally a challenging task, because nonlinear and chaotic variables may be positively coupled or correlated for some periods of time, but can then become spontaneously decoupled or non-correlated. In his 2002 paper (Faybishenko, 2002), the author performed a nonlinear dynamical and chaotic analysis of time-series data obtained from the fracture flow experiment conducted by Persoff and Pruess (1995), and, based on the visual examination of time series data, hypothesized that the observed pressure oscillations at both inlet and outlet edges of the fracture result from a superposition of both forward and return waves of pressure propagation through the fracture. In the current paper, the author explores an application of a combination of methods for detecting nonlinear chaotic dynamics behavior along with the multivariate Granger Causality (G-causality) time series test. Based on the G-causality test, the author infers that his hypothesis is correct, and presents a causation loop diagram of the spatial-temporal distribution of gas, liquid, and capillary pressures measured at the inlet and outlet of the fracture. The causal modeling approach can be used for the analysis of other hydrological processes, for example, infiltration and pumping tests in heterogeneous subsurface media, and climatic processes, for example, to find correlations between various meteorological parameters, such as temperature, solar radiation, barometric pressure, etc.

Hypoglossal-facial nerve "side"-to-side neurorrhaphy for facial paralysis resulting from closed temporal bone fractures.

PubMed

Su, Diya; Li, Dezhi; Wang, Shiwei; Qiao, Hui; Li, Ping; Wang, Binbin; Wan, Hong; Schumacher, Michael; Liu, Song

2018-06-06

Closed temporal bone fractures due to cranial trauma often result in facial nerve injury, frequently inducing incomplete facial paralysis. Conventional hypoglossal-facial nerve end-to-end neurorrhaphy may not be suitable for these injuries because sacrifice of the lesioned facial nerve for neurorrhaphy destroys the remnant axons and/or potential spontaneous innervation. we modified the classical method by hypoglossal-facial nerve "side"-to-side neurorrhaphy using an interpositional predegenerated nerve graft to treat these injuries. Five patients who experienced facial paralysis resulting from closed temporal bone fractures due to cranial trauma were treated with the "side"-to-side neurorrhaphy. An additional 4 patients did not receive the neurorrhaphy and served as controls. Before treatment, all patients had suffered House-Brackmann (H-B) grade V or VI facial paralysis for a mean of 5 months. During the 12-30 months of follow-up period, no further detectable deficits were observed, but an improvement in facial nerve function was evidenced over time in the 5 neurorrhaphy-treated patients. At the end of follow-up, the improved facial function reached H-B grade II in 3, grade III in 1 and grade IV in 1 of the 5 patients, consistent with the electrophysiological examinations. In the control group, two patients showed slightly spontaneous innervation with facial function improved from H-B grade VI to V, and the other patients remained unchanged at H-B grade V or VI. We concluded that the hypoglossal-facial nerve "side"-to-side neurorrhaphy can preserve the injured facial nerve and is suitable for treating significant incomplete facial paralysis resulting from closed temporal bone fractures, providing an evident beneficial effect. Moreover, this treatment may be performed earlier after the onset of facial paralysis in order to reduce the unfavorable changes to the injured facial nerve and atrophy of its target muscles due to long-term denervation and allow axonal regrowth in a rich supportive environment.

Dissolution-induced preferential flow in a limestone fracture.

PubMed

Liu, Jishan; Polak, Amir; Elsworth, Derek; Grader, Avrami

2005-06-01

Flow in a rock fracture is surprisingly sensitive to the evolution of flow paths that develop as a result of dissolution. Net dissolution may either increase or decrease permeability uniformly within the fracture, or may form a preferential flow path through which most of the injected fluid flows, depending on the prevailing ambient mechanical and chemical conditions. A flow-through test was completed on an artificial fracture in limestone at room temperature under ambient confining stress of 3.5 MPa. The sample was sequentially circulated by water of two different compositions through the 1500 h duration of the experiment; the first 935 h by tap groundwater, followed by 555 h of distilled water. Measurements of differential pressures between the inlet and the outlet, fluid and dissolved mass fluxes, and concurrent X-ray CT imaging and sectioning were used to characterize the evolution of flow paths within the limestone fracture. During the initial circulation of groundwater, the differential pressure increased almost threefold, and was interpreted as a net reduction in permeability as the contacting asperities across the fracture are removed, and the fracture closes. With the circulation of distilled water, permeability initially reduces threefold, and ultimately increases by two orders of magnitude. This spontaneous switch from net decrease in permeability, to net increase occurred with no change in flow rate or applied effective stress, and is attributed to the evolving localization of flow path as evidenced by CT images. Based on the X-ray CT characterizations, a flow path-dependent flow model was developed to simulate the evolution of flow paths within the fracture and its influence on the overall flow behaviors of the injected fluid in the fracture.

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.

Lumbar vertebral haemangioma causing pathological fracture, epidural haemorrhage, and cord compression: a case report and review of literature.

PubMed

Vinay, S; Khan, S K; Braybrooke, J R

2011-01-01

Vertebral haemangiomas are recognized to be one of the commonest benign tumours of the vertebral column, occurring mostly in the thoracic spine. The vast majority of these are asymptomatic. Infrequently, these can turn symptomatic and cause neurological deficit (cord compression) through any of four reported mechanisms: (1) epidural extension; (2) expansion of the involved vertebra(e) causing spinal canal stenosis; (3) spontaneous epidural haemorrhage; (4) pathological burst fracture. Thoracic haemangiomas have been reported to be more likely to produce cord compression than lumbar haemangiomas. A forty-nine year old male with acute onset spinal cord compression from a pathological fracture in a first lumbar vertebral haemangioma. An MRI delineated the haemangioma and extent of bleeding that caused the cord compression. These were confirmed during surgery and the haematoma was evacuated. The spine was instrumented from T12 to L2, and a cement vertebroplasty was performed intra-operatively. Written consent for publication was obtained from the patient. The junctional location of the first lumbar vertebra, and the structural weakness from normal bone being replaced by the haemangioma, probably caused it to fracture under axial loading. This pathological fracture caused bleeding from the vascularized bone, resulting in cord compression.

Lumbar vertebral haemangioma causing pathological fracture, epidural haemorrhage, and cord compression: a case report and review of literature

PubMed Central

Vinay, S; Khan, SK; Braybrooke, JR

2011-01-01

Context Vertebral haemangiomas are recognized to be one of the commonest benign tumours of the vertebral column, occurring mostly in the thoracic spine. The vast majority of these are asymptomatic. Infrequently, these can turn symptomatic and cause neurological deficit (cord compression) through any of four reported mechanisms: (1) epidural extension; (2) expansion of the involved vertebra(e) causing spinal canal stenosis; (3) spontaneous epidural haemorrhage; (4) pathological burst fracture. Thoracic haemangiomas have been reported to be more likely to produce cord compression than lumbar haemangiomas. Findings A forty-nine year old male with acute onset spinal cord compression from a pathological fracture in a first lumbar vertebral haemangioma. An MRI delineated the haemangioma and extent of bleeding that caused the cord compression. These were confirmed during surgery and the haematoma was evacuated. The spine was instrumented from T12 to L2, and a cement vertebroplasty was performed intra-operatively. Written consent for publication was obtained from the patient. Clinical Relevance The junctional location of the first lumbar vertebra, and the structural weakness from normal bone being replaced by the haemangioma, probably caused it to fracture under axial loading. This pathological fracture caused bleeding from the vascularized bone, resulting in cord compression. PMID:21756575

Spontaneous Imbibition Process in Micro-Nano Fractal Capillaries Considering Slip Flow

NASA Astrophysics Data System (ADS)

Shen, Yinghao; Li, Caoxiong; Ge, Hongkui; Guo, Xuejing; Wang, Shaojun

An imbibition process of water into a matrix is required to investigate the influences of large-volume fracturing fluids on gas production of unconventional formations. Slip flow has been recognized by recent studies as a major mechanism of fluid transport in nanotubes. For nanopores in shale, a slip boundary is nonnegligible in the imbibition process. In this study, we established an analytic equation of spontaneous imbibition considering slip effects in capillaries. A spontaneous imbibition model that couples the analytic equation considering the slip effect was constructed based on fractal theory. We then used a model for various conditions, such as slip boundary, pore structure, and fractal dimension of pore tortuosity, to capture the imbibition characteristics considering the slip effect. A dynamic contact angle was integrated into the modeling. Results of our study verify that the slip boundary influences water imbibition significantly. The imbibition speed is significantly improved when slip length reaches the equivalent diameter of a tube. Therefore, disregarding the slip effect will underestimate the imbibition speed in shale samples.

Hématome spontané du méso de l'angle colique droit et du colon transverse compliquant un traitement par anti vitamine K: à propos d'un cas et revue de la littérature

PubMed Central

Traoré, Ibrahim Alain; Zaré, Cyprien; Barro, Sié Drissa; Guibla, Ismaël

2016-01-01

L'hématome spontané du méso de l'angle colique droit et du transverse est une complication rare du traitement anticoagulant par antivitamine K. Nous rapportons un cas d'hématome spontané du méso de l'angle colique droit et du transverse associé à un hémopéritoine de grande abondance chez un patient traité par antivitamine K pour embolie pulmonaire consécutive à une fracture des plateaux tibiaux droits. Le diagnostic doit être fait en urgence. L’échographie abdominale et la tomodensitométrie confirment le diagnostic. Le traitement non opératoire est la règle. Le traitement chirurgical est indiqué en cas de complications telles que la rupture de l'hématome. PMID:27217878

Free radical reaction characteristics of coal low-temperature oxidation and its inhibition method.

PubMed

Li, Zenghua; Kong, Biao; Wei, Aizhu; Yang, Yongliang; Zhou, Yinbo; Zhang, Lanzhun

2016-12-01

Study on the mechanism of coal spontaneous combustion is significant for controlling fire disasters due to coal spontaneous combustion. The free radical reactions can explain the chemical process of coal at low-temperature oxidation. Electron spin resonance (ESR) spectroscopy was used to measure the change rules of the different sorts and different granularity of coal directly; ESR spectroscopy chart of free radicals following the changes of temperatures was compared by the coal samples applying air and blowing nitrogen, original coal samples, dry coal samples, and demineralized coal samples. The fragmentation process was the key factor of producing and initiating free radical reactions. Oxygen, moisture, and mineral accelerated the free radical reactions. Combination of the free radical reaction mechanism, the mechanical fragmentation leaded to the elevated CO concentration, fracturing of coal pillar was more prone to spontaneous combustion, and spontaneous combustion in goaf accounted for a large proportion of the fire in the mine were explained. The method of added diphenylamine can inhibit the self-oxidation of coal effectively, the action mechanism of diphenylamine was analyzed by free radical chain reaction, and this research can offer new method for the development of new flame retardant.

Subtalar dislocation without associated fractures: Case report and review of literature

PubMed Central

Giannoulis, Dionisios; Papadopoulos, Dimitrios V; Lykissas, Marios G; Koulouvaris, Panagiotis; Gkiatas, Ioannis; Mavrodontidis, Alexandros

2015-01-01

Isolated subtalar dislocations are unusual injuries due to the inherent instability of the talus. Subtalar dislocations are frequently associated with fractures of the malleoli, the talus, the calcaneus or the fifth metatarsal. Four types of subtalar dislocation have been described according to the direction of the foot in relation to the talus: medial, lateral posterior and anterior. It has been shown that some of these dislocations may spontaneously reduce. A rare case of a 36-year-old male patient who sustained a closed medial subtalar dislocation without any associated fractures of the ankle is reported. The patient suffered a pure closed medial subtalar dislocation that is hardly reported in the literature. Six months after injury the patient did not report any pain, had a satisfactory range of motion, and no signs of residual instability or early posttraumatic osteoarthritis. The traumatic mechanism, the treatment options, and the importance of a stable and prompt closed reduction and early mobilization are discussed. PMID:25893182

Massive osteolysis of the right clavicle developing after radiation therapy

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

Skinner, W.L.; Buzdar, A.U.; Libshitz, H.I.

1988-07-15

This report describes an unusual case of clavicular osteolysis, a late complication of radiation therapy for breast cancer, and demonstrates the diagnostic implications that radiotherapy changes can pose. Radiotherapy to the chest wall produces a spectrum of alterations in bone over time, ranging from early roentgenographic findings of osteoporosis and trabecular thickening to spontaneous fractures and changes that may be confused with metastatic disease or postirradiation sarcoma.

Diagnostic Tools for Performance Evaluation of Innovative In-Situ Remediation Technologies at Chlorinated Solvent-Contaminated Sites

DTIC Science & Technology

2011-07-01

fluid resistivity , temperature logging, and flow metering at other sites that typically indicated only two or three active fractures in each hole...was consistent with results of conventional borehole fluid resistivity , temperature logging, and flow metering at other sites that typically indicated...following tests were performed in each boundary monitoring well: ■ Gamma Ray; ■ Spontaneous Potential (SP); ■ Single Point Resistance (SPR

Rapid Spontaneous Redistribution of Acute Epidural Hematoma : Case Report and Literature Review

PubMed Central

Eom, Ki Seong; Park, Jong Tae; Kim, Tae Young

2009-01-01

Acute epidural hematoma (AEDH) occurring as a result of traumatic head injury constitutes one of the most critical emergencies in neurosurgery. However, there are only several reports that show the rapid disappearance of AEDH without surgical intervention. We suggest redistribution of hematoma through the overlying skull fractures as the mechanism of rapid disappearance of AEDH. A 13-year-old female fell from a height of about 2 m and presented with mild headache. A computed tomography (CT) scan performed 4 hours after the injury revealed an AEDH with an overlying fracture in the right temporal region and acute small hemorrhagic contusion in the left frontal region. A repeat CT scan 16 hours after injury revealed that the AEDH had almost completely disappeared and showed an increase in the epicranial hematoma. The patient was discharged 10 days after injury with no neurological deficits. This case is characterized by the rapid disappearance of an AEDH associated with an overlying skull fracture. We believe that the rapid disappearance of the AEDH is due to the redistribution of the hematoma, rather than its resolution or absorption, and fracture plays a key role in this process. PMID:19274119

Mutiple Spontaneous Rib Fractures in Patient with Cushing's Syndrome.

PubMed

Lee, Hyun Jung; Je, Ji Hye; Seo, Ji Hye; Na, Young Ju; Yoo, Hye Jin

2014-11-01

Glucocorticoid (GC) excess, including Cushing's syndrome, is a common cause of secondary osteoporosis. Thirty to fifty percent of Cushing's syndrome patients experience non-traumatic fractures, which is often the presenting manifestation of Cushing's syndrome. However, there have been rare cases of Cushing's syndrome diagnosed only based upon bone manifestations. We describe a case of Cushing's syndrome that was diagnosed in a 44-year-old woman who initially visited our hospital due to multiple non-traumatic rib fractures. She did not exhibit any other manifestations of Cushing's syndrome such as moon face, buffalo hump or abdominal striae. Initially, we evaluated her for bone metastases from a cancer of unknown origin, but there was no evidence of metastatic cancer. Instead, we found a left adrenal incidentaloma. As a result of the hormone study, she was diagnosed as having Cushing's syndrome. Interestingly, her bony manifestation of Cushing's syndrome, which was evident in the bone scan and bone mineral densitometry, completely recovered after a left adrenalectomy. Therefore, the possibility of Cushing's syndrome as a cause of secondary osteoporosis should be considered in young patients with non-traumatic multiple fractures, with or without any other typical features of Cushing's syndrome.

Osteoporosis presenting in pregnancy, puerperium, and lactation.

PubMed

Kovacs, Christopher S

2014-12-01

To describe our current state of knowledge about the pathophysiology, incidence, and treatment of osteoporosis that presents during pregnancy, puerperium, and lactation. When vertebral fractures occur in pregnant or lactating women, it is usually unknown whether the skeleton was normal before pregnancy. Maternal adaptations increase bone resorption modestly during pregnancy but markedly during lactation. The net bone loss may occasionally precipitate fractures, especially in women who have underlying low bone mass or skeletal fragility prior to pregnancy. Bone mass and strength are normally restored postweaning. Transient osteoporosis of the hip is a sporadic disorder localized to one or both femoral heads; it is not due to generalized skeletal resorption. Anecdotal reports have used bisphosphonates, strontium ranelate, teriparatide, or vertebroplasty/kyphoplasty to treat postpartum vertebral fractures, but it is unclear whether these therapies had any added benefit over the spontaneous skeletal recovery that normally occurs after weaning. These relatively rare fragility fractures result from multifactorial causes, including skeletal disorders that precede pregnancy, and structural and metabolic stresses that can compromise skeletal strength during pregnancy and lactation. Further study is needed to determine when pharmacological or surgical therapy is warranted instead of conservative or expectant management.

[Calcium and bone metabolism across women's life stages. Pathophysiology, adiagnosis and treatment of post-pregnancy osteoporosis.

PubMed

Kurabayashi, Takumi

Post-pregnancy osteoporosis is a rare condition with little known pathophysiology. Most cases are diagnosed in the late stage of pregnancy or in the post-partum while breastfeeding, particularly in first pregnancy. Vertebral fractures are most commonly observed and characterized by prolonged severe pain and functional limitations. Measurements of bone mineral density(BMD)of the lumbar spine and proximal femur with dual energy X-ray absorptiometry(DXA)are the clinical methods most commonly used for no fracture women. Conventional radiography will confirm the fracture in most cases, and magnetic resonance(MR), which can be safely used during pregnancy, is effective in detecting vertebral fractures and bone marrow edema. Although the bone resorption increased at the end of pregnancy and lactation, the bone formation increases and the bone structure is almost recovered after cessation of lactating in postpartum. There is much uncertainty about whether pharmacological treatments should be used for osteoporosis that presents during pregnancy and lactation. This is partly because of the lack of a firm evidence base for treatment and also because there is a spontaneous recovery of bone mass and strength after pregnancy or weaning.

Closed Versus Open Supracondylar Fractures of the Humerus in Children: A Comparison of Clinical and Radiographic Presentation and Results.

PubMed

Lewine, Eliza; Kim, Jaehon M; Miller, Patricia E; Waters, Peter M; Mahan, Susan T; Snyder, Brian; Hedequist, Daniel; Bae, Donald S

2018-02-01

The purpose of this investigation was to compare the presentation and postoperative results of children treated for open and closed, completely displaced type III supracondylar humerus fractures (SCFs). Thirty patients with open and 66 patients with closed, completely displaced type III SCFs were evaluated. Open fractures underwent irrigation and debridement, and all patients were treated by open or closed reduction and pin fixation. Medical records were reviewed to obtain demographic information as well as preoperative and postoperative clinical data regarding mechanism of injury, neurovascular status, associated injuries, postoperative range of motion, infections, and pain. Radiographs were evaluated to quantify displacement, Baumann's angle, humeral capitellar angle, position of the anterior humeral line, and adequacy of reduction. Outcomes were assessed using Flynn criteria. Mean clinical follow-up for the open and closed fracture groups was 8.9 and 5.7 months, respectively. Both groups were similar with respect to age, sex distribution, weight and body mass index, laterality of involvement, and mechanism of injury. At presentation, 35% of closed SCFs and 23% of open SCFs presented with abnormal neurovascular status. There was a higher prevalence of diminished/absent pulses or distal limb ischemia in patients with open injuries (27%) compared with closed fractures (18%). Conversely, severely displaced closed fractures were more commonly associated with nerve injury/palsy at presentation (35%) than those with open fractures (23%). Spontaneous nerve recovery was seen in 87% within 3 to 6 months. Postoperative loss of reduction and malunion were more common in the closed fracture group. However, 84% of patients achieved good-to-excellent results by Flynn criteria, with no appreciable difference based upon open versus closed fractures. With timely wound and fracture treatment, the clinical and radiographic results of children treated for open SCFs is similar to those with closed type III injuries, with little increased risk for infection, malunion, or neurovascular compromise. Level III.

Use of whole body CT to detect patterns of CPR-related injuries after sudden cardiac arrest.

PubMed

Dunham, Gregor M; Perez-Girbes, Alexandre; Bolster, Ferdia; Sheehan, Kellie; Linnau, Ken F

2017-11-09

We have recently implemented a dedicated sudden cardiac arrest (SCA) - whole-body computed tomography (WBCT) protocol to evaluate SCA patients with return of spontaneous circulation (ROSC) following cardiopulmonary resuscitation (CPR). The aim of this study is to evaluate the number and pattern of CPR-related injuries in ROSC patients with SCA-WBCT. Single-centre retrospective review of 39 patients (13 female; 20 male, mean age 51.8 years) with non-traumatic, out-of-hospital SCA and ROSC and evaluation with dedicated SCA-WBCT over a 10-month period. In-hospital mortality was 54%. CPR-related injuries were detected in 85% (33/39). Chest injuries were most common on WBCT: 85% (33) subjects had rib fractures (mean of 8.5 fractures/subject); 31% (12) sternal fractures; 13% (5) mediastinal haematoma; 10% (4) pneumothorax; 8% (3) pneumomediastinum and 3% (1) haemothorax. Three subjects (8%) had abdominal injuries on WBCT, including one hepatic haematoma with active haemorrhage. CPR-related injuries on WBCT after ROSC are common, with serial rib fractures detected most commonly. An unexpectedly high rate of abdominal injuries was detected on SCA-WBCT. Radiologists need to be attuned to the spectrum of CPR-related injuries in WBCT, including abdominal injuries and subtle rib fractures. • CPR frequently causes injuries. • Radiologists should be aware of the spectrum of CPR related injuries. • Rib fractures are frequent and radiologic findings often subtle. • Clinically unexpected abdominal injuries may be present.

Simvastatin Prodrug Micelles Target Fracture and Improve Healing

PubMed Central

Dusad, Anand; Yuan, Hongjiang; Ren, Ke; Li, Fei; Fehringer, Edward V.; Purdue, P. Edward; Goldring, Steven R.; Daluiski, Aaron; Wang, Dong

2014-01-01

Simvastatin (SIM), a widely used anti-lipidaemic drug, has been identified as a bone anabolic agent. Its poor water solubility and the lack of distribution to the skeleton, however, have limited its application in the treatment of bone metabolic diseases. In this study, an amphiphilic macromolecular prodrug of SIM was designed and synthesized to overcome these limitations. The polyethylene glycol (PEG)-based prodrug can spontaneously self-assemble to form micelles. The use of SIM trimer as the prodrug’s hydrophobic segment allows easy encapsulation of additional free SIM. The in vitro studies showed that SIM/SIM-mPEG micelles were internalized by MC3T3 cells via lysosomal trafficking and consistently induced expression of both BMP2 and DKK1 mRNA, suggesting that the prodrug micelle retains the biological functions of SIM. After systemic administration, optical imaging suggests that the micelles would passively target to bone fracture sites associated with hematoma and inflammation. Furthermore, flow cytometry study revealed that SIM/SIM-mPEG micelles had preferred cellular uptake by inflammatory and resident cells within the fracture callus tissue. The treatment study using a mouse osteotomy model validated the micelles’ therapeutic efficacy in promoting bone fracture healing as demonstrated by micro-CT and histological analyses. Collectively, these data suggest that the macromolecular prodrug-based micelle formulation of SIM may have great potential for clinical management of impaired fracture healing. PMID:25542644

Spontaneous pneumocephalus after commercial air travel complicated by meningitis.

PubMed

Javan, Ramin; Duszak, Richard; Eisenberg, Alan D; Eggers, Frank M

2011-12-01

Pneumocephalus usually results from trauma, infection, neoplasm, or iatrogenic causes. Barotrauma-induced spontaneous pneumocephalus is extremely rare, usually seen in divers or occassionally with air travel. We report a case of a 61-yr-old female presenting with confusion, fever, and respiratory failure one day after developing sudden nausea, vomiting, and headache during descent on a commercial airliner. Pneumocephalus and meningitis were present on admission. Sinus computed tomography (CT) showed pansinusitis and a tiny bone defect in the posterior wall of the right sphenoid sinus, through which a cisternogram later showed free communication with the prepontine cistern. An orbital CT 2 yr earlier after a fall showed the bone defect, with no other areas of abnormality or fracture. After repair of defects by otolaryngology and appropriate antibiotics, she did well and was eventually discharged. Changes in aircraft cabin pressure likely resulted in rupture of dura and arachnoid layers beneath the pre-existing bony defect, predisposed by existing sinus disease. The pathophysiology, implications, and potential sources of spontaneous pneumocephalus, as well as risks of postcraniotomy and post-trauma air-travel, are discussed.

A Cohort Study of the Natural History of Odontoid Pseudoarthrosis Managed Nonoperatively in Elderly Patients.

PubMed

Hong, Jennifer; Zaman, Rifat; Coy, Shannon; Pastel, David; Simmons, Nathan; Ball, Perry; Mirza, Sohail; Abdu, William; Pearson, Adam; Lollis, S Scott

2018-06-01

Although the primary goal of treatment of type II odontoid fracture is bony union, some advocate continued nonsurgical management of minimally symptomatic older patients who have fibrous union or minimal fracture motion. The risk of this strategy is unknown. We reviewed our long-term outcomes after dens nonunion to define the natural history of Type II odontoid fractures in elderly patients managed nonoperatively. A retrospective chart review of 50 consecutive adults aged 65 or older with Type II odontoid fracture initially managed nonsurgically from 1998 to 2012 at a single tertiary care institution was conducted. Particular attention was paid to patients who had orthosis removal despite absent bony fusion. Patients were contacted prospectively by telephone and followed until death, surgical intervention, or last known contact. Fifty patients initially were managed nonsurgically; of these, 21 (42.0%) proceeded to bony fusion, 3 (6%) underwent delayed surgery for persistent instability, and 26 (52%) had orthosis removal despite the lack of solid arthrodesis on imaging. The last group had a median follow-up of 25 months (range 4-158 months), with 20 of 26 (76.9%) followed until death. Of these patients, 1 patient developed progressive quadriplegia and dysphagia 11 months after initial injury. Compared with patients with spontaneous union, patients with nonunion had shorter life expectancy, despite no significant differences between the groups with respect to age, sex, injury mechanism, radiographic variables, or follow-up duration. Orthosis removal despite fracture nonunion may be reasonable in elderly patients with Type II dens fractures. Copyright © 2018 Elsevier Inc. All rights reserved.

[An Unusual Case of Acute Epidural Hematoma Showing Rapid Spontaneous Resolution with Delayed Recurrence].

PubMed

Yokoyama, Takahiro; Sugimoto, Tetsuaki; Yoneyama, Takumi; Futami, Munetomo; Takeshima, Hideo

2018-05-01

A 16-year-old boy collided with a passenger car while riding a motorcycle. He was thrown to a distance and experienced a head injury on impact. When brought to our medical facility, he was alert, had no neurological abnormalities, and did not complain of headache. A head computed tomography(CT)scan indicated a left cranial fracture and an acute epidural hematoma(15mm thick)directly under the fracture. Follow-up head CT performed 3 hours after the injury indicated no change in the size of the hematoma. The head CT performed on the following day indicated that most of the hematoma had disappeared. As the patient had neither headache nor neurological symptoms, he was placed under observation. However, a head CT performed 7 days after the injury indicated the formation of an epidural hematoma approximately the same size as the initial hematoma and located at the same site. We performed craniotomy to evacuate the hematoma, identify the source of the bleeding, and restore hemostasis. Although cases in which an acute epidural hematoma rapidly and spontaneously resolves have been reported, these are extremely rare. Recurrence of an epidural hematoma despite normal blood coagulation function after its initial rapid resolution has not been reported yet. We report on this rare case of acute epidural hematoma with reference to relevant literatures.

[Homolateral Monteggia and Galeazzi fractures: a case report and review of the literature].

PubMed

Kanso, I; Tawil, H J; Lignac, F

2002-05-01

We report a very rare case of Monteggia and Galeazzi fractures of the same forearm in a 23-year-old female traffic accident victim. Fractures of the two forearm bones were reduced and fixed with a solid assembly. Dislocation of the radial head reduced spontaneously. Inferior radioulnar instability was treated by blocking the joint with a K wire for one month. At 24 months, outcome was satisfactory with 40 degrees pronation and 70 degrees supination. Elbow and wrist flexion-extension and muscle force were the same as on the healthy side. Surgery is indicated in this rare association in adults. As it is very important to restore exactly the anatomy with solid fixation of the ulna to achieve and maintain reduction of the radial head. Surgical exploration of the humeroradial joint is not required unless reduction cannot be achieved. The same is true for fixation of the radius after Galeazzi fracture. If an inferior radioulnar instability persists, we propose temporary stabilization with a K wire. Our experience with this case would argue against first intention resection of the distal portion of the ulna as proposed by Hughston. We prefer to postpone resection which would be performed only in case of bothersome instability. A Sauvé-Kapandji procedure would then be a possible solution.

A web-based multicriteria evaluation of spatial trade-offs between environmental and economic implications from hydraulic fracturing in a shale gas region in Ohio.

PubMed

Liu, X; Gorsevski, P V; Yacobucci, M M; Onasch, C M

2016-06-01

Planning of shale gas infrastructure and drilling sites for hydraulic fracturing has important spatial implications. The evaluation of conflicting and competing objectives requires an explicit consideration of multiple criteria as they have important environmental and economic implications. This study presents a web-based multicriteria spatial decision support system (SDSS) prototype with a flexible and user-friendly interface that could provide educational or decision-making capabilities with respect to hydraulic fracturing site selection in eastern Ohio. One of the main features of this SDSS is to emphasize potential trade-offs between important factors of environmental and economic ramifications from hydraulic fracturing activities using a weighted linear combination (WLC) method. In the prototype, the GIS-enabled analytical components allow spontaneous visualization of available alternatives on maps which provide value-added features for decision support processes and derivation of final decision maps. The SDSS prototype also facilitates nonexpert participation capabilities using a mapping module, decision-making tool, group decision module, and social media sharing tools. The logical flow of successively presented forms and standardized criteria maps is used to generate visualization of trade-off scenarios and alternative solutions tailored to individual user's preferences that are graphed for subsequent decision-making.

SURFACTANT BASED ENHANCED OIL RECOVERY AND FOAM MOBILITY CONTROL

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

George J. Hirasaki; Clarence A. Miller; Gary A. Pope

2004-07-01

Surfactant flooding has the potential to significantly increase recovery over that of conventional waterflooding. The availability of a large number of surfactants makes it possible to conduct a systematic study of the relation between surfactant structure and its efficacy for oil recovery. Also, the addition of an alkali such as sodium carbonate makes possible in situ generation of surfactant and significant reduction of surfactant adsorption. In addition to reduction of interfacial tension to ultra-low values, surfactants and alkali can be designed to alter wettability to enhance oil recovery. An alkaline surfactant process is designed to enhance spontaneous imbibition in fractured,more » oil-wet, carbonate formations. It is able to recover oil from dolomite core samples from which there was no oil recovery when placed in formation brine. Mobility control is essential for surfactant EOR. Foam is evaluted to improve the sweep efficiency of surfactant injected into fractured reservoirs. UTCHEM is a reservoir simulator specially designed for surfactant EOR. A dual-porosity version is demonstrated as a potential scale-up tool for fractured reservoirs.« less

THE TREATMENT OF IRRADIATION FRACTURE OF THE FEMORAL NECK

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

Leabhart, J.W.; Bonfiglio, M.

1961-10-01

Treatment of 44 patients with 56 postirradiation fractures of the femoral neck is reported. Of 2612 patients who received pelvic irradiation for carcinoma of the uterine cervix, 40 developed fractures of the femoral neck, an incidence of 1.5%. Sixteen of the 40 patients had bilateral fractures. The average age of the patients was 58.5 yr at the time of irradiation. The average irradiation dose was approximates 3600 r (parametrial dose), the largest dose being 4235 r. The average interval from irradiation to the onset of pain in the hip was 36.6 months (3 to 240 months) and from the onsetmore » of pain to diagnosis, 3 months. Forty-six surgical procedures were performed: 36 as primary treatment and 9 because of failure or complications of the first procedure. The average follow-up time of these patients was 6.9 yr. The presenting complaint was usually spontaneous onset of pain in the groin and medial portion of the thigh. Initially the physical examination often revealed only restriction of internal rotation of the affected hip, and the roentgenograms appeared normal in some instances. Subsequently, a change in bone density was noted at the inferior aspect of the femoral neck, denoting an adduction type of fracture. The displaced fractures resembled the traumatic adduction fractures of the femoral neck seen in patients who had not received irradiation. Acetabular changes were also noted, characterized by marked osteoporosis and occasionally fracture of the acetabulum. Seven methods of primary therapy were used to treat these patients: no treatment, nonsurgical measures (crutches or bedrest), internal fixation, bone- grafting (with and without additional fixation), osteotomy, arthroplasty, and the insertion of a prosthesis. Early in situ internal fixation or internal fixation with bone grafts was the procedure of choice in fractures of the femorai neck secondary to irradiation. Reconstructive procedures, such as cup arthroplasty or insertion of a prosthesis, were effective treatment in selected cases. Osteotomy was not applicable for primary treatment of this type of fracture. (H.H.D.)« less

Dynamic fracture network around faults: implications for earthquake ruptures, ground motion and energy budget

NASA Astrophysics Data System (ADS)

Okubo, K.; Bhat, H. S.; Rougier, E.; Lei, Z.; Knight, E. E.; Klinger, Y.

2017-12-01

Numerous studies have suggested that spontaneous earthquake ruptures can dynamically induce failure in secondary fracture network, regarded as damage zone around faults. The feedbacks of such fracture network play a crucial role in earthquake rupture, its radiated wave field and the total energy budget. A novel numerical modeling tool based on the combined finite-discrete element method (FDEM), which accounts for the main rupture propagation and nucleation/propagation of secondary cracks, was used to quantify the evolution of the fracture network and evaluate its effects on the main rupture and its associated radiation. The simulations were performed with the FDEM-based software tool, Hybrid Optimization Software Suite (HOSSedu) developed by Los Alamos National Laboratory. We first modeled an earthquake rupture on a planar strike-slip fault surrounded by a brittle medium where secondary cracks can be nucleated/activated by the earthquake rupture. We show that the secondary cracks are dynamically generated dominantly on the extensional side of the fault, mainly behind the rupture front, and it forms an intricate network of fractures in the damage zone. The rupture velocity thereby significantly decreases, by 10 to 20 percent, while the supershear transition length increases in comparison to the one with purely elastic medium. It is also observed that the high-frequency component (10 to 100 Hz) of the near-field ground acceleration is enhanced by the dynamically activated fracture network, consistent with field observations. We then conducted the case study in depth with various sets of initial stress state, and friction properties, to investigate the evolution of damage zone. We show that the width of damage zone decreases in depth, forming "flower-like" structure as the characteristic slip distance in linear slip-weakening law, or the fracture energy on the fault, is kept constant with depth. Finally, we compared the fracture energy on the fault to the energy absorbed by the secondary fracture network to better understand the earthquake energy budget. We conclude that the secondary fracture network plays an important role on the dynamic earthquake rupture, its radiated wave field and the overall energy budget.

Identification, characterization, and analysis of hydraulically conductive fractures in granitic basement rocks, Millville, Massachusetts

USGS Publications Warehouse

Paillet, Frederick L.; Ollila, P.W.

1994-01-01

A suite of geophysical logs designed to identify and characterize fractures and water production in fractures was run in six bedrock boreholes at a ground-water contamination site near the towns of Millville and Uxbridge in south-central Massachusetts. The geophysical logs used in this study included conventional gamma, single-point resistance, borehole fluid resistivity, caliper, spontaneous potential, and temperature; and the borehole televiewer and heat-pulse flowmeter, which are not usually used to log bedrock water-supply wells. Downward flow under ambient hydraulic-head conditions was measured in three of the boreholes at the site, and the profile of fluid column resistivity inferred from the logs indicated downward flow in all six boreholes. Steady injection tests at about 1.0 gallon per minute were used to identify fractures capable of conducting flow under test conditions. Sixteen of 157 fracturesidentified on the televiewer logs and interpreted as permeable fractures in the data analysis were determined to conduct flow under ambient hydraulic-head conditions or during injection. Hydraulic-head monitoring in the bedrock boreholes indicated a consistent head difference between the upper and lower parts of the boreholes. This naturally occurring hydraulic-head condition may account, in part, for the transport of contaminants from the overlying soil into the bedrock aquifer. The downward flow may also account for the decrease in contaminant concentrations found in some boreholes after routine use of the boreholes as water-supply wells was discontinued.

Acidization of shales with calcite cemented fractures

NASA Astrophysics Data System (ADS)

Kwiatkowski, Kamil; Szymczak, Piotr; Jarosiński, Marek

2017-04-01

Investigation of cores drilled from shale formations reveals a relatively large number of calcite-cemented fractures. Usually such fractures are reactivated during fracking and can contribute considerably to the permeability of the resulting fracture network. However, calcite coating on their surfaces effectively excludes them from production. Dissolution of the calcite cement by acidic fluids is investigated numerically with focus on the evolution of fracture morphology. Available surface area, breakthrough time, and reactant penetration length are calculated. Natural fractures in cores from Pomeranian shale formation (northern Poland) were analyzed and classified. Representative fractures are relatively thin (0.1 mm), flat and completely sealed with calcite. Next, the morphology evolution of reactivated natural fractures treated with low-pH fluids has been simulated numerically under various operating conditions. Depth-averaged equations for fracture flow and reactant transport has been solved by finite-difference method coupled with sparse-matrix solver. Transport-limited dissolution has been considered, which corresponds to the treatment with strong acids, such as HCl. Calcite coating in reactivated natural fractures dissolves in a highly non-homogeneous manner - a positive feedback between fluid transport and calcite dissolution leads to the spontaneous formation of wormhole-like patterns, in which most of the flow is focused. The wormholes carry reactive fluids deeper inside the system, which dramatically increases the range of the treatment. Non-uniformity of the dissolution patterns provides a way of retaining the fracture permeability even in the absence of the proppant, since the less dissolved regions will act as supports to keep more dissolved regions open. Evolution of fracture morphology is shown to depend strongly on the thickness of calcite layer - the thicker the coating the more pronounced wormholes are observed. However the interaction between wormholes is the strongest when coating thickness is a few times larger than the initial aperture of the fracture. This leads to formation of favorable complex networks of wormholes which provide adequate transport of reactive fluids to fracture surfaces and - at the same time - are capable of supporting fracture surfaces. As a conclusion, acidization of the reactivated fractures with hydrochloric acid seems to be an attractive treatment to apply at fracking stage or later on as EGR. The results contribute to the discussion on the use of acidization to enhance the gas production in the shale reservoirs. This communication stresses the importance of the dissolution of calcite cement in natural fractures in shale formations, which are initially sealed and become reactivated during fracking. While this research is based on the analysis of fractures in the Pomeranian shale basin its results are general enough to be applicable to different formations worldwide.

Use of Advanced Technologies and New Procedures in Medical Field Operations (Utilisation de technologies avancees et de procedures nouvelles dans les operations sanitaires)

DTIC Science & Technology

2010-04-01

that are now digitally enhanced and also part-task trainers (attrappe). Paper 12 – Using Advanced Prosthetics for Stress Inoculation Training and to...concept of minimum treatment called the “Just seven procedure”: just bridge the fracture , just align the limb, just stiff enough to allow evacuation...require energy, some more than others. Oxygen economizing systems like on-demand valves should be compulsory for spontaneous ventilation. Pulseoximeters

Permeability evolution due to dissolution of natural shale fractures reactivated by fracking

NASA Astrophysics Data System (ADS)

Kwiatkowski, Kamil; Kwiatkowski, Tomasz; Szymczak, Piotr

2015-04-01

Investigation of cores drilled from gas-bearing shale formations reveals a relatively large number of calcite-cemented fractures. During fracking, some of these fractures will be reactivated [1-2] and may become important flow paths in the resulting fracture system. In this communication, we investigate numerically the effect of low-pH reactive fluid on such fractures. The low-pH fluids can either be pumped during the initial fracking stage (as suggested e.g. by Grieser et al., [3]) or injected later, as part of enhanced gas recovery (EGR) processes. In particular, it has been suggested that CO2 injection can be considered as a method of EGR [4], which is attractive as it can potentially be combined with simultaneous CO2 sequestration. However, when mixed with brine, CO2 becomes acidic and thus can be a dissolving agent for the carbonate cement in the fractures. The dissolution of the cement leads to the enhancement of permeability and interconnectivity of the fracture network and, as a result, increases the overall capacity of the reservoir. Importantly, we show that the dissolution of such fractures proceeds in a highly non-homogeneous manner - a positive feedback between fluid transport and mineral dissolution leads to the spontaneous formation of pronounced flow channels, frequently referred to as "wormholes". The wormholes carry the chemically active fluid deeper inside the system, which dramatically speeds up the overall permeability increase. If the low-pH fluids are used during fracking, then the non-uniform dissolution becomes important for retaining the fracture permeability, even in the absence of the proppant. Whereas a uniformly etched fracture will close tightly under the overburden once the fluid pressure is removed, the nonuniform etching will tend to maintain the permeability since the less dissolved regions will act as supports to keep more dissolved regions open. [1] Gale, J. F., Reed, R. M., Holder, J. (2007). Natural fractures in the Barnett Shale and their importance for hydraulic fracture treatments. AAPG bulletin, 91(4), 603-622. [2] Walton, I., & McLennan, J. (2013, May). The Role of Natural Fractures in Shale Gas Production. In ISRM International Conference for Effective and Sustainable Hydraulic Fracturing. International Society for Rock Mechanics. [3] Grieser, W. et al. "Surface Reactive Fluid's Effect on Shale." Proceedings of the Production and Operations Symposium, 31 March-3 April 2007, Oklahoma City (SPE-106815-MS) [4] Khosrokhavar, R., Griffiths, S., & Wolf, K. H. (2014). Shale Gas Formations and Their Potential for Carbon Storage: Opportunities and Outlook. Environmental Processes, 1(4), 595-611.

Fires in Operating or Abandoned Coal Mines or Heaps of Reactive Materials and the Governing Transport and Reaction Processes

NASA Astrophysics Data System (ADS)

Wuttke, M. W.; Kessels, W.; Wessling, S.; Han, J.

2007-05-01

Spontaneous combustion is a world wide problem for technical operations in mining, waste disposal and power plant facilities. The principle driving the combustion is every where the same independent of the different reactive materials: Fresh air with the common oxygen content is getting in contact with the reactive material by human operations. The following reaction process produces heat at a usually low but constant rate. The reactive material in operating or abandoned coal mines, heaps of coal, waste or reactive minerals is most times strongly broken or fractured, such that the atmospheric oxygen can deeply penetrate into the porous or fractured media. Because the strongly broken or fractured medium with air filled pores and fractures is often combined with a low thermal conductivity of the bulk material the produced heat accumulates and the temperature increases with time. If the reactivity strongly increases with temperature, the temperature rise accelerates up to the "combustion temperature". Once the temperature is high enough the combustion process is determined by the oxygen transport to the combustion center rather than the chemical reactivity. Spontaneous combustion is thus a self- amplifying process where an initial small variation in the parameters and the starting conditions can create exploding combustion hot spots in an apparently homogenous material. The phenomenon will be discussed by various examples in the context of the German - Sino coal fire project. A temperature monitoring in hot fracture systems documents the strong influence of the weather conditions on the combustion process. Numerical calculations show the sensitivity of the combustion to the model geometries, the boundary conditions and mainly the permeability. The most used fire fighting operations like covering and water injection are discussed. A new method of using saltwater for fire fighting is presented and discussed. References: Kessels, W., Wessling, S., Li, X., and Wuttke, M. W. Numerical element distinction for reactive transport modeling regarding reaction rate. In Proceedings of MODFLOW and MORE 2006: Managing Groundwater Systems, May 21 - 24, 2006, Golden, CO USA (2006). Kessels, W., Wuttke, M. W., Wessling, S., and Li, X. Coal fires between self ignition and fire fighting: Numerical modeling and basic geophysical measurements. In ERSEC Ecological Book Series - 4 on Coal Fire Research (2007). Wessling, S., Litschke, T., Wiegand, J., Schlömer, S., and Kessels, W. Simulating dynamic subsurface coal fires and its applications. In ERSEC Ecological Book Series - 4 on Coal Fire Reserach (2007). Wessling, S., Kessels, W., Schmidt, M., and Krause, U. Investigating dynamic underground coal fires by means of numerical simulation. Geophys. J. Int. (submitted).

Fatal spontaneous Clostridium septicum gas gangrene: a possible association with iatrogenic gastric acid suppression.

PubMed

Wu, Yiru E; Baras, Alexander; Cornish, Toby; Riedel, Stefan; Burton, Elizabeth C

2014-06-01

The long-term use of proton pump inhibitors has been linked to an increased risk for the development of gastric polyps, hip fractures, pneumonia, and Clostridium difficile colitis. There is evidence that chronic acid suppression from long-term use of proton pump inhibitors poses some risk for the development of C difficile-associated diarrhea by decreasing the elimination of pathogenic microbes before reaching the lower gastrointestinal tract. Here we present a case of a 51-year-old woman with a recent history of abdominal pain and fever who presented to the emergency department with rapidly progressive spontaneous necrotizing fasciitis and gas gangrene and died within hours of presentation. Postmortem examination confirmed spreading tissue gas gangrene and myonecrosis. In addition, multiple intestinal ulcers containing Clostridium septicum were present at autopsy. This case illustrates a possible association between proton pump inhibitor therapy and fatal C septicum infection.

MuSET, A High Precision Logging Sensor For Downhole Spontaneous Electrical Potential.

NASA Astrophysics Data System (ADS)

Pezard, P. A.; Gautier, S.; Le Borgne, T.; Deltombe, J.

2008-12-01

MuSET has been designed by ALT and CNRS in the context of the EC ALIANCE research project. It is based on an existing multi-parameter borehole fluid sensor (p, T, Cw, pH, Eh) built by ALT. The new downhole geophysical tool aims to measure subsurface spontaneous electrical potentials (SP) in situ with great precision (< µV). For this, the device includes an unpolazirable Pb/PbCl2 electrode referred to a similar one at surface. Initial field testing in Montpellier (Languedoc, France), Ploemeur (Brittany, France) and Campos (Mallorca, Spain) took advantage of the set of field sites developed as part of ALIANCE then as part of the environmental research observatory (ORE) network for hydrogeology "H+". While Cretaceous marly limestone at Lavalette (Montpellier) proved to be almost exclusively the source of membrane potential, the clay-starved Miocene reefal carbonates of Campos generate a signal dominated by electrokinetic potential. This signal is generated due to nearby agricultural pumping, and associated strong horizontal flow. At the top of the salt to fresh water transtion, a discrepancy between the SP signal and the absence of vertical flow measured with a heat-pulse flowmeter hints at a capacity to detect the "fluid-junction", diffusion potential. At Ploemeur, the altered granite found in the vicinity of faults and fractures is also the source of a SP signal, mostly surface related while most fractures appear to be closed. In all, the MuSET demonstrates a capacity to identify several subsurface sources of natural electrical potential such as diffusion ones (membrane potential in the presence of clays, fickean processes due to pore fluid salinity gradients), or else the electrokinetic potential with pore fluid pressure gradients. While spontaneous electrical currents often loop out of the borehole, MuSET might be used as a radial electrical flowmeter once the diffusion components taken into account.

Cracks dynamics under tensional stress - a DEM approach

NASA Astrophysics Data System (ADS)

Debski, Wojciech; Klejment, Piotr; Kosmala, Alicja; Foltyn, Natalia; Szpindler, Maciej

2017-04-01

Breaking and fragmentation of solid materials is an extremely complex process involving scales ranging from an atomic scale (breaking inter-atomic bounds) up to thousands of kilometers in case of catastrophic earthquakes (in energy scale it ranges from single eV up to 1024 J). Such a large scale span of breaking processes opens lot of questions like, for example, scaling of breaking processes, existence of factors controlling final size of broken area, existence of precursors, dynamics of fragmentation, to name a few. The classical approach to study breaking process at seismological scales, i.e., physical processes in earthquake foci, is essentially based on two factors: seismic data (mostly) and the continuum mechanics (including the linear fracture mechanics). Such approach has been gratefully successful in developing kinematic (first) and dynamic (recently) models of seismic rupture and explaining many of earthquake features observed all around the globe. However, such approach will sooner or latter face a limitation due to a limited information content of seismic data and inherit limitations of the fracture mechanics principles. A way of avoiding this expected limitation is turning an attention towards a well established in physics method of computational simulations - a powerful branch of contemporary physics. In this presentation we discuss preliminary results of analysis of fracturing dynamics under external tensional forces using the Discrete Element Method approach. We demonstrate that even under a very simplified tensional conditions, the fragmentation dynamics is a very complex process, including multi-fracturing, spontaneous fracture generation and healing, etc. We also emphasis a role of material heterogeneity on the fragmentation process.

Fracture of the penis. A report of two cases.

PubMed

Ugwu, B T; Liman, H U; Sani, A A; Mohammed, A M

2009-06-01

We present two cases of fracture of the penis in two young men at the extremes of the social strata the first an unemployed tailor while the other a practicing engineer. The first one was a bachelor while the other was married with children. In the first case, the fracture occurred during masturbation while in the second case it occurred during consensual intercourse with his wife on top. In the first case the fracture occurred at the base of the penis with associated rupture of the deep dorsal vein while in the second case it affected the mid-shaft with urethral rupture and blood at the tip of the penis at presentation. Both of them presented within two hours of their injuries with deformed, swollen and tender penis. Laubscher's subcoronal sleeve operation with evacuation of clots and repair of the tear with absorbable sutures to ensure a leak-proof repair was promptly performed with no complications. Both patients experienced spontaneous erection whilst in hospital even with indwelling catheter in place. The wife of the second case became pregnant six months after the repair. Counseling was successful with the engineer but was unsuccessful with the tailor-bachelor who continued with masturbation despite professional help. Though we published the first case of fracture of the penis in this centre almost a decade ago, we still found it necessary to report these new cases managed after we created awareness of this uncommon condition in our environment in order to highlight the presentations and the factors that influenced outcome.

Isolated olecranon fractures in children affected by osteogenesis imperfecta type I treated with single screw or tension band wiring system: Outcomes and pitfalls in relation to bone mineral density.

PubMed

Persiani, Pietro; Ranaldi, Filippo M; Graci, Jole; De Cristo, Claudia; Zambrano, Anna; D'Eufemia, Patrizia; Martini, Lorena; Villani, Ciro

2017-05-01

The purpose of this study is to compare the results of 2 techniques, tension band wiring (TBW) and fixation with screws, in olecranon fractures in children affected with osteogenesis imperfecta (OI) type I. Between 2010 and 2014, 21 olecranon fractures in 18 children with OI (average age: 12 years old) were treated surgically. Ten patients were treated with the screw fixation and 11 with TBW. A total of 65% of olecranon fractures occurred as a result of a spontaneous avulsion of the olecranon during the contraction of the triceps muscle. The average follow-up was 36 months. Among the children treated with 1 screw, 5 patients needed a surgical revision with TBW due to a mobilization of the screw. In this group, the satisfactory results were 50%. In patients treated with TBW, the satisfactory results were 100% of the cases. The average Z-score, the last one recorded in the patients before the trauma, was -2.53 in patients treated with screw fixation and -2.04 in those treated with TBW. TBW represents the safest surgical treatment for patients suffering from OI type I, as it helps to prevent the rigidity of the elbow through an earlier recovery of the range of motion, and there was no loosening of the implant. In analyzing the average Z-score before any fracture, the fixation with screws has an increased risk of failure in combination with low bone mineral density.

Unconventional Liquid Flow in Low-Permeability Media: Theory and Revisiting Darcy's Law

NASA Astrophysics Data System (ADS)

Liu, H. H.; Chen, J.

2017-12-01

About 80% of fracturing fluid remains in shale formations after hydraulic fracturing and the flow back process. It is critical to understand and accurately model the flow process of fracturing fluids in a shale formation, because the flow has many practical applications for shale gas recovery. Owing to the strong solid-liquid interaction in low-permeability media, Darcy's law is not always adequate for describing liquid flow process in a shale formation. This non-Darcy flow behavior (characterized by nonlinearity of the relationship between liquid flux and hydraulic gradient), however, has not been given enough attention in the shale gas community. The current study develops a systematic methodology to address this important issue. We developed a phenomenological model for liquid flow in shale (in which liquid flux is a power function of pressure gradient), an extension of the conventional Darcy's law, and also a methodology to estimate parameters for the phenomenological model from spontaneous imbibition tests. The validity of our new developments is verified by satisfactory comparisons of theoretical results and observations from our and other research groups. The relative importance of this non-Darcy liquid flow for hydrocarbon production in unconventional reservoirs remains an issue that needs to be further investigated.

Application of Borehole Geophysical Methods for Assessing Agro-Chemical Flow Paths in Fractured Bedrock Underlying the Black Brook Watershed, Northwestern New Brunswick

NASA Astrophysics Data System (ADS)

Desroches, A.; Butler, K.

2009-05-01

The upper Saint John River valley represents an economically important agricultural region that suffers from high nitrate levels in the groundwater as a result of fertilizer use. This study focuses on the fractured bedrock aquifer beneath the Black Brook Watershed, near Saint-Andre (Grand Falls), New Brunswick, where prediction of nitrate migration is limited by a lack of knowledge of the bedrock fracture characteristics. Bedrock consists of a fine-grained, siliciclastic unit of the Grog Brook Group gradationally overlain by a carbonate unit assigned to the Matapédia Group. Groundwater flow through the fractured bedrock is expected to be primarily influenced by the distribution and orientation of fractures in these rock units. This study demonstrates the effectiveness of the select suite of borehole-geophysical tools used to identify and describe the fractured bedrock characteristics, and assists in understanding the migration pathways of agrochemical leachate from farm fields. Fracture datasets were acquired from five new vertical boreholes that ranged from 50 to 140 metres in depth, and from three outcrop locations along the new Trans-Canada Highway, approximately two kilometres away. The borehole-geophysical methods used included natural gamma ray (GR), single point resistance (SPR), spontaneous potential (SP), slim-hole optical borehole televiewer (OBI) and acoustic borehole televiewer (ABI). The ABI and OBI tools delivered high-resolution oriented images of the borehole walls, and enabled visualization of fractures in situ, and provided accurate information on the location, orientation, and aperture. The GR, SPR and SP logs identified changes in lithology, bed thickness and conductive fracture zones. Detailed inspection of the borehole televiewer images identified 390 fractures. Equal-area stereographic and rose diagrams of fracture planes have been used to identify three discrete fracture sets: 1) steeply dipping fractures that strike 068o/248o, with fracture subsets dipping roughly 70o to 80o towards the N-NW and S-SE; 2) steeply dipping fractures that strike towards 156o/336o, with fracture subsets dipping roughly 70o to 80o towards the NE and SW; and 3) primary set of moderately dipping fractures that strike 074o/254o and dip roughly 30o to 40o towards the SE. The strike of the steeply dipping fracture sets are oriented roughly perpendicular to each other, reflecting two distinct fracture generation events. The low-angle fractures are most common and correspond to openings along bedding planes that dip roughly 38o towards 164o. This is a result of penetrating only one limb of a fold; presumably a similar set of bedding-plane openings occur along the adjacent limb of the fold, with resultant fracture dips towards the northwest. Fractures exposed in outcrops along the Trans-Canada Highway exhibit a similar orientation distribution to that observed in the boreholes. However, as expected, these exposures show a greater proportion of fractures with dips between 80o and 90o, compared to the vertical boreholes. A Terzaghi fracture probability correction was applied to the boreholes in order to account for this bias. The combined fracture datasets provide valuable information towards understanding groundwater flow and migration pathways of fertilizer leachate into the bedrock aquifer, and will lead to the development of more complex hydrogeological models.

Principles of management of osteometabolic disorders affecting the aging spine.

PubMed

Hadjipavlou, Alexander G; Katonis, Paul G; Tzermiadianos, Michael N; Tsoukas, George M; Sapkas, George

2003-10-01

Osteoporosis is the most common contributing factor of spinal fractures, which characteristically are not generally known to produce spinal cord compression symptoms. Recently, an increasing number of medical reports have implicated osteoporotic fractures as a cause of serious neurological deficit and painful disabling spinal deformities. This has been corroborated by the present authors as well. These complications are only amenable to surgical management, requiring instrumentation. Instrumenting an osteoporotic spine, although a challenging task, can be accomplished if certain guidelines for surgical techniques are respected. Neurological deficits respond equally well to an anterior or posterior decompression, provided this is coupled with multisegmental fixation of the construct. With the steady increase in the elderly population, it is anticipated that the spine surgeon will face serious complications of osteoporotic spines more frequently. With regard to surgery, however, excellent correction of deformities can be achieved, by combining anterior and posterior approaches. Paget's disease of bone (PD) is a non-hormonal osteometabolic disorder and the spine is the second most commonly affected site. About one-third of patients with spinal involvement exhibit symptoms of clinical stenosis. In only 12-24% of patients with PD of the spine is back pain attributed solely to PD, while in the majority of patients, back pain is either arthritic in nature or a combination of a pagetic process and coexisting arthritis. In this context, one must be certain before attributing low back pain to PD exclusively, and antipagetic medical treatment alone may be ineffective. Neural element dysfunction may be attributed to compressive myelopathy by pagetic bone overgrowth, pagetic intraspinal soft tissue overgrowth, ossification of epidural fat, platybasia, spontaneous bleeding, sarcomatous degeneration and vertebral fracture or subluxation. Neural dysfunction can also result from spinal ischemia when blood is diverted by the so-called "arterial steal syndrome". Because the effectiveness of pharmacologic treatment for pagetic spinal stenosis has been clearly demonstrated, surgical decompression should only be instituted after failure of antipagetic medical treatment. Surgery is indicated as a primary treatment when neural compression is secondary to pathologic fractures, dislocations, spontaneous epidural hematoma, syringomyelia, platybasia, or sarcomatous transformation. Five classes of drugs are available for the treatment of PD. Bisphosphonates are the most popular antipagetic drug and several forms have been investigated.

Use of advanced borehole geophysical techniques to delineate fractured-rock ground-water flow and fractures along water-tunnel facilities in northern Queens County, New York

USGS Publications Warehouse

Stumm, Frederick; Chu, Anthony; Lange, Andrew D.; Paillet, Frederick L.; Williams, John H.; Lane, John W.

2001-01-01

Advanced borehole geophysical methods were used to assess the geohydrology of crystalline bedrock along the course of a new water tunnel for New York City. The logging methods include natural gamma, spontaneous potential, single-point resistance, mechanical and acoustic caliper, focused electromagnetic induction, electromagnetic resistivity, magnetic susceptibility, borehole-fluid temperature and conductance, differential temperature, heat-pulse flowmeter, acoustic televiewer, borehole deviation, optical televiewer, and borehole radar. Integrated interpretation of the geophysical logs from an 825-foot borehole (1) provided information on the extent, orientation, and structure (foliation and fractures) within the entire borehole, including intensely fractured intervals from which core recovery may be poor; (2) delineated transmissive fracture zones intersected by the borehole and provided estimates of their transmissivity and hydraulic head; and (3) enabled mapping of the location and orientation of structures at distances as much as 100 ft from the borehole.Analyses of the borehole-wall image and the geophysical logs from the borehole on Crescent Street, in northern Queens County, are presented here to illustrate the application of the methods. The borehole penetrates gneiss and other crystalline bedrock that has predominantly southeastward dipping foliation and nearly horizontal and southeastward-dipping fractures. The heat-pulse flowmeter logs obtained under pumping and nonpumping conditions, together with the other geophysical logs, indicate five transmissive fracture zones. More than 90 percent of the open-hole transmissivity is associated with a fracture zone 272 feet BLS (below land surface). A transmissive zone at 787 feet BLS that consists of nearly parallel fractures lies within the projected tunnel path; here the hydraulic head is 12 to 15 feet lower than that of transmissive zones above the 315-foot depth. The 60-megahertz directional borehole radar logs indicate the location and orientation of two closely spaced radar reflectors that would intersect the projection of the borehole below its drilled depth.Subsequent excavation of the tunnel past the borehole allowed comparison of the log analysis with conditions observed in the tunnel. The tunnel was found to intersect gneiss with southeastward dipping foliation; many nearly horizontal fractures; and a southeastward dipping fracture zone whose location, character, and orientation was consistent with that of the mapped radar reflectors. The fracture zone produced inflow to the tunnel at a rate of 50 to 100 gallons per minute. All conditions indicated by the logging methods were consistent with those observed within the tunnel.

Characterization and comparison of injuries caused by spontaneous versus organized dogfighting.

PubMed

Intarapanich, Nida P; Touroo, Rachel M; Rozanski, Elizabeth A; Reisman, Robert W; Intarapanich, Pichai P; McCobb, Emily C

2017-12-15

OBJECTIVE To characterize and compare injuries found in dogs involved in spontaneously occurring dogfights with those of dogs used in illegal organized dogfighting. DESIGN Retrospective case-control study. ANIMALS 36 medium-sized dogs evaluated following spontaneous fights with a dog of the same sex and similar weight (medium dog-medium dog [MDMD] fights), 160 small dogs examined following spontaneous fights with a larger dog (big dog-little dog [BDLD] fights), and 62 dogs evaluated after being seized in connection with dogfighting law enforcement raids. PROCEDURES Demographic characteristics and injuries were recorded from medical records. Prevalence of soft tissue injuries in predetermined body surface zones, as well as dental or skeletal injuries, was determined for dogs grouped by involvement in BDLD, MDMD, and organized dogfights. The extent of injuries in each location was scored and compared among groups by 1-factor ANOVA. Patterns of injuries commonly incurred by each group were determined by use of prevalence data. RESULTS Mean extent of injury scores differed significantly among groups for all body surface zones except the eye and periorbital region. Mean scores for dental injuries and rib fractures also differed significantly among groups. Organized fighting dogs more commonly had multiple injuries, particularly of the thoracic limbs, dorsal and lateral aspects of the head and muzzle or oral mucosa, dorsal and lateral aspects of the neck, and ventral neck and thoracic region. CONCLUSIONS AND CLINICAL RELEVANCE To the authors' knowledge, this was the first study to compare injuries incurred during spontaneous and organized dogfighting. Establishing evidence-based patterns of injury will help clinicians identify dogs injured by organized dogfighting and aid in the prosecution of this crime.

Inadvertent transposition of defibrillator coil terminal pins causing inappropriate ICD therapies.

PubMed

Issa, Ziad F

2008-06-01

We report the case of a 65-year-old man with chronic atrial fibrillation (AF) and severe ischemic cardiomyopathy who underwent implantation of a prophylactic single-chamber implantable cardioverter-defibrillator (ICD). The patient experienced inappropriate ICD therapies due to oversensing of pectoral muscle myopotential secondary to reversal of the defibrillator coil terminal pins in the ICD header. Recognizing this possibility is important to avoid misinterpretation of spontaneous oversensing as hardware failure (e.g., lead fracture or insulation breech) and potentially unnecessary ICD system surgical intervention, including lead extraction.

Titanium-Oxygen Reactivity Study

NASA Technical Reports Server (NTRS)

Chafey, J. E.; Scheck, W. G.; Witzell, W. E.

1962-01-01

A program has been conducted at Astronautics to investigate the likelihood of occurrence of the catastrophic oxidation of titanium alloy sheet under conditions which simulate certain cases of accidental failure of the metal while it is in contact with liquid or gaseous oxygen. Three methods of fracturing the metal were used; they consisted of mechanical puncture, tensile fracture of welded joints, and perforation by very high velocity particles. The results of the tests which have been conducted provide further evidence of the reactivity of titanium with liquid and gaseous oxygen. The evidence indicates that the rapid fracturing of titanium sheet while it is in contact with oxygen initiates the catastrophic oxidation reaction. Initiation occurred when the speed of the fracture was some few feet per second, as in both the drop-weight puncture tests and the static tensile fracture tests of welded joints, as well as when the speed was several thousand feet per second, as in the simulated micrometeoroid penetration tests. The slow propagation of a crack, however, did not initiate the reaction. It may logically be concluded that the localized frictional heat of rapid fracture and/or spontaneous oxidation (exothermic) of minute particles emanating from the fracture cause initiation of the reaction. Under conditions of slow fracture, however, the small heat generated may be adequately dissipated and the reaction is not initiated. A portion of the study conducted consisted of investigating various means by which the reaction might be retarded or prevented. Providing a "barrier" at the titanium-oxygen interface consisting of either aluminum metal or a coating of a petroleum base corrosion inhibitor appeared to be only partially effective in retarding the reaction. The accidental puncturing or similar rupturing of thin-walled pressurized oxygen tanks on missiles and space vehicle will usually constitute loss of function, and may sometimes cause their catastrophic destruction by explosive decompression regardless of the type of material used for their construction. In the case of tanks constructed of titanium alloys the added risk is incurred of catastrophic burning of the tanks. In view of this it is recommended that thin-walled tanks constructed of titanium alloys should not be used to contain liquid or gaseous oxygen.

J-integral fracture toughness and tearing modulus measurement of radiation cross-linked UHMWPE.

PubMed

Gomoll, A; Wanich, T; Bellare, A

2002-11-01

Radiation and chemical cross-linking of medical grade ultrahigh molecular weight polyethylene (UHMWPE) has recently been utilized in an effort to improve wear performance of total joint replacement components. However, reductions in mechanical properties with cross-linking are cause for concern regarding the use of cross-linked UHMWPE for high-stress applications such as in total knee replacement prostheses. In this study, the fracture behavior of radiation cross-linked UHMWPE was compared to that of uncross-linked UHMWPE. The Rice and Sorensen model that utilizes mechanical parameters obtained from uniaxial tensile and compact tension tests was used to calculate the steady state J-integral fracture toughness, Jss, for radiation cross-linked UHMWPE. Jss decreased monotonically with increase in radiation dose. UHMWPE exhibited tough, ductile tearing behavior with stable crack growth when it was cross-linked using a gamma radiation dose of 0-50 kGy. However, in cross-linked UHMWPE irradiated to a dose of 100 and 200 kGy, unstable fracture occurred spontaneously upon attaining the initial crack driving force, J1c. This indicates that a high degree of cross-linking is less desirable for high-stress applications in orthopaedic implants. However, a substantial increase in J1c, even at a low degree of cross-linking, suggests that a low degree of cross-linking may be beneficial for resistance to delamination and catastrophic failure, both of which require an initiation step for the fracture to propagate in the material. This mechanical test should, however, be considered along with fatigue tests and joint simulator testing before determination of an appropriate amount of cross-linking for total joint replacement prostheses that experience high stresses.

The Incidence of Atypical Femoral Fractures in Patients with Rheumatic Disease: Yamagata Prefectural Committee of Atypical Femoral Fractures (YamaCAFe) Study.

PubMed

Takakubo, Yuya; Ohta, Daichi; Ishi, Masaji; Ito, Juji; Oki, Hiroharu; Naganuma, Yasushi; Uno, Tomohiro; Sasaki, Akiko; Akabane, Takeru; Dairaku, Katsuyuki; Goto, Shinichi; Goto, Yasuo; Kanauchi, Yumiko; Kobayashi, Shinji; Nakajima, Taku; Masuda, Keiji; Matsuda, Michiharu; Mura, Nariyuki; Takenouchi, Kenji; Tsuchida, Hiroyuki; Onuma, Yasushi; Shibuya, Junichirou; Seino, Mitsuyoshi; Yamaguchi, Osamu; Hiragami, Ken; Urayama, Yasuhiro; Furukawa, Takashi; Okuda, Shouta; Ogura, Ken; Nakamura, Takeshi; Sasaki, Kan; Konta, Tsuneo; Takagi, Michiaki

2017-08-01

Atypical femoral fractures (AFFs) have been reported to occur with minimal or spontaneous subtrochanteric and femoral shaft fractures with a characteristic transverse pattern, compared with typical femoral fractures in young patients with high-energy trauma. AFFs are related to long-term use of bisphosphonates (BPs), glucocorticoids and rheumatic diseases. We have estimated a blind analysis of AFFs in rheumatic patients receiving BPs and glucocorticoids ordinary over a long time in all Yamagata prefectural area through radiographic examination. The 123 AFFs including suspected cases over six years were collected and reviewed by two independent orthopedic surgeons. We found 86 patients with a total of 99 AFFs between 2009 and 2014 (1.43 cases/100,000 person/year). Of these 99 AFFs, 11 were in 8 rheumatic patients including three patients with bilateral AFFs. The incidence of AFFs in rheumatic patients had trend to increase from 2012. The mean age of all 8 patients was 54.9 years. All 8 patients received BPs and 7/8 received prednisolone (PSL). The mean dose of PSL was 14 mg/day. Compared to patients with unilateral AFFs, those with bilateral AFFs in rheumatic patients were on a higher dose of PSL (20 mg/day vs. 7 mg/day) and had less femoral neck-shaft angle (129° vs. 136°, p < 0.05). In conclusion, the incidence of AFFs in rheumatic patients showed a trend to increase from 2012 to 2014 in Yamagata prefecture. Careful management of AFFs is of particular importance in rheumatic patients who have taken high doses of PSL and have small femoral neck-shaft angle.

Natural flows of H2-rich fluids in the ophiolites of Oman and the Philippines: Tectonic control of migration pathways and associated diagenetic processes

NASA Astrophysics Data System (ADS)

Deville, E. P.; Prinzhofer, A.; Vacquand, C.; Chavagnac, V.; Monnin, C.; Ceuleneer, G.; Arcilla, C. A.

2009-12-01

We compare the geological environments of sites of emission of natural hydrogen in the Oman ophiolite and the Zambales ophiolite (Luzon, Philippines). The genesis of natural H2 results from the interaction between ultrabasic rocks and aqueous solutions circulating in deep fracture networks, by oxidation of metals (Fe2+, Mn2+) and reduction of water, probably under high temperature conditions. This process generates very reducing conditions capable of destabilizing other molecules (notably reduction of deep CO2 being transformed into CH4 by Fisher-Tropsch type reactions). Nitrogen is also commonly associated to the H2-rich fluids. H2 flows are associated with the expulsion of hyperalkaline waters rich in ions OH- and Ca2+ and characterized by high pH (between 11 and 12). Most alkaline springs are found in the vicinity of major faults and/or lithological discontinuities like the basal thrust plane of the ophiolites and the peridotite-gabbro contact (Moho). Within the fracture networks, gas and water separate probably at shallow depth, i.e. close to the top of the upper aquifer level. Locally high flows of gas migrate vertically through fracture pathways and they are able to inflame spontaneously on the surface. Aqueous fluids tends to migrate laterally in the fracture network toward the creeks where most of the hyperalkaline springs are found. This water circulation induces a chain of diagenetic reactions starting in the fracture systems and continuing at the surface where it leads to the precipitation of calcite, aragonite, brucite and more rarely portlandite. This chain of diagenetic reactions is associated with the capture of the atmospheric CO2 during the precipitation of carbonates.

A novel methodology for in-process monitoring of flow forming

NASA Astrophysics Data System (ADS)

Appleby, Andrew; Conway, Alastair; Ion, William

2017-10-01

Flow forming (FF) is an incremental cold working process with near-net-shape forming capability. Failures by fracture due to high deformation can be unexpected and sometimes catastrophic, causing tool damage. If process failures can be identified in real time, an automatic cut-out could prevent costly tool damage. Sound and vibration monitoring is well established and commercially viable in the machining sector to detect current and incipient process failures, but not for FF. A broad-frequency microphone was used to record the sound signature of the manufacturing cycle for a series of FF parts. Parts were flow formed using single and multiple passes, and flaws were introduced into some of the parts to simulate the presence of spontaneously initiated cracks. The results show that this methodology is capable of identifying both introduced defects and spontaneous failures during flow forming. Further investigation is needed to categorise and identify different modes of failure and identify further potential applications in rotary forming.

Recent Advances and Future of Gene Therapy for Bone Regeneration.

PubMed

Shapiro, Galina; Lieber, Raphael; Gazit, Dan; Pelled, Gadi

2018-06-16

The purpose of this review is to discuss the recent advances in gene therapy as a treatment for bone regeneration. While most fractures heal spontaneously, patients who present with fracture nonunion suffer from prolonged pain, disability, and often require additional operations to regain musculoskeletal function. In the last few years, BMP gene delivery by means of electroporation and sonoporation resulted in repair of nonunion bone defects in mice, rats, and minipigs. Ex vivo transfection of porcine mesenchymal stem cells (MSCs) resulted in bone regeneration following implantation in vertebral defects of minipigs. Sustained release of VEGF gene from a collagen-hydroxyapatite scaffold to the mandible of a human patient was shown to be safe and osteoinductive. In conclusion, gene therapy methods for bone regeneration are systematically becoming more efficient and show proof-of-concept in clinically relevant animal models. Yet, on the pathway to clinical use, more investigation is needed to determine the safety aspects of the various techniques in terms of biodistribution, toxicity, and tumorigenicity.

Shear rheological characterization of gel healing response and construction of rheo-PIV system

NASA Astrophysics Data System (ADS)

Bawiskar, Abhishek D.

Thermo-reversible gels are solvent-filled 3D networks of polymer chains interconnected by physical (transient) crosslinks. On applying a high shear stress, the crosslinks are broken and these gels show a typical stress-strain behavior due to cohesive fracture of the gel. When heated above a critical temperature and cooled back to room temperature, all the crosslinks are re-formed. Interestingly, partial to full recovery of broken crosslinks is also observed by simply letting the gel stand at room temperature. In this study, the fracture and healing behavior of a model acrylic triblock copolymer gel has been characterized by shear rheometry. A mathematical model has also been proposed to better understand the mechanics at the molecular level and predict the healing time of a system. A rheo-PIV system was built as part of the project, to observe and confirm the bulk healing process in situ. Spontaneous self-healing behavior has immense potential in controlled drug delivery systems, coatings, food and various other applications.

Spontaneous electric current flow during deformation of non-piezoelectric marble samples: an indicator of stress state?

NASA Astrophysics Data System (ADS)

Cartwright-Taylor, A. L.; Sammonds, P. R.; Vallianatos, F.

2016-12-01

We recorded spontaneous electric current flow in non-piezoelectric Carrara marble samples during triaxial deformation. Mechanical data, ultrasonic velocities and acoustic emissions were acquired simultaneously with electric current to constrain the relationship between electric current flow, differential stress and damage. Under strain-controlled loading, spontaneous electric current signals (nA) were generated and sustained under all conditions tested. In dry samples, a detectable electric current arises only during dilatancy and is correlated with the damage induced by microcracking. Signal variations with confining pressure correspond to microcrack suppression, while variations with strain rate are associated with time-dependent differences in deformation mechanism across the brittle to semi-brittle transition. In the brittle regime, the signal exhibits a precursory change as damage localises and the stress drop accelerates towards failure. This change is particularly distinct at dynamic strain rates. Similar changes are seen in the semi-brittle regime although the signal is more oscillatory in nature. Current flow in dry samples is proportional to stress within 90% of peak stress. In fluid-saturated samples proportionality holds from 40% peak stress, with a significant increase in the rate of current production from 90% peak stress associated with fluid flow during dilatancy. This direct relationship demonstrates that electric current could be used as a proxy for stress, indicating when the rock is reaching the limit of its strength. The experimental power law relationship between electric current and strain rate, which mirrors the power-law creep equation, supports this observation. High-frequency fluctuations of electric current are not normally distributed - they exhibit `heavy-tails'. We model these distributions with q-Gaussian statistics and evolution of the q-parameter during deformation reveals a two-stage precursory anomaly prior to sample failure, consistent with the acoustic emissions b-value and stress intensity evolution as modelled from fracture mechanics. Our findings support the idea that electric currents in the crust can be generated purely from solid state fracture processes and that these currents may reflect the stress state within the damaged rock.

Label-free Raman spectroscopy provides early determination and precise localization of breast cancer-colonized bone alterations.

PubMed

Zhang, Chi; Winnard, Paul T; Dasari, Sidarth; Kominsky, Scott L; Doucet, Michele; Jayaraman, Swaathi; Raman, Venu; Barman, Ishan

2018-01-21

Breast neoplasms frequently colonize bone and induce development of osteolytic bone lesions by disrupting the homeostasis of the bone microenvironment. This degenerative process can lead to bone pain and pathological bone fracture, a major cause of cancer morbidity and diminished quality of life, which is exacerbated by our limited ability to monitor early metastatic disease in bone and assess fracture risk. Spurred by its label-free, real-time nature and its exquisite molecular specificity, we employed spontaneous Raman spectroscopy to assess and quantify early metastasis driven biochemical alterations to bone composition. As early as two weeks after intracardiac inoculations of MDA-MB-435 breast cancer cells in NOD-SCID mice, Raman spectroscopic measurements in the femur and spine revealed consistent changes in carbonate substitution, overall mineralization as well as crystallinity increase in tumor-bearing bones when compared with their normal counterparts. Our observations reveal the possibility of early stage detection of biochemical changes in the tumor-bearing bones - significantly before morphological variations are captured through radiographic diagnosis. This study paves the way for a better molecular understanding of altered bone remodeling in such metastatic niches, and for further clinical studies with the goal of establishing a non-invasive tool for early metastasis detection and prediction of pathological fracture risk in breast cancer.

Temporary Percutaneous Instrumentation and Selective Anterior Fusion for Thoracolumbar Fractures.

PubMed

Charles, Yann Philippe; Walter, Axel; Schuller, Sébastien; Steib, Jean-Paul

2017-05-01

Prospective clinical trial in thoracolumbar trauma with 5-year follow-up. To analyze clinical and radiographic outcomes of minimal invasive surgery, and the rational of circumferential fracture treatment with regard to age, degenerative changes, bone mineral density, and global sagittal balance. Non-neurologic fractures with anterior column defect can be treated by posterior percutaneous instrumentation and selective anterior fusion. After consolidation, instrumentation can be removed at 1 year to provide mobility in non-fused segments. Fifty-one patients, 47 (18-75) years, were operated for A2, A3, or B-type fractures. Visual analog scale (VAS) for back pain and Oswestry Disability Index (ODI) were assessed. Radiographic measurements were: sagittal index, regional kyphosis, T4-T12 kyphosis, L1-S1 lordosis, pelvic incidence, pelvic tilt, sacral slope, and T9 tilt. Anterior fusion and facet joints were analyzed on computed tomography (CT) at 1 year. The ODI was 8.8 before accident, 35.4 at 3 months, 17.8 at 2 years, 14.4 at 5 years. The VAS was 2.0 at 3 months and 1.0 at 5 years. The sagittal index was 18.0° preoperatively and 1.0° at 3 months (P < 0.0001). A loss of reduction of 1.1° occurred after implant removal (P = 0.009). Global sagittal balance remained unchanged. Ten patients with osteopenia or osteoporosis had a worse ODI: 24.7 versus 11.9 (P = 0.016), and a greater loss of correction: 4.9° versus 1.3° (P = 0.007). Cages filled with cancellous bone from the fractured vertebra fused regularly. Spontaneous facet joint fusions were observed in two patients at the fracture level in B-type injuries. Percutaneous instrumentation and selective anterior fusion using autologous bone and mesh cages lead to high fusion rates, which provided good long-term clinical results in younger patients with thoracolumbar fractures. Sagittal alignment was maintained after instrumentation removal without damaging paravertebral muscles. Outcomes were worse in elderly patients presenting osteopenia or osteoporosis. 3.

Conservative treatment of a mandibular condyle fracture: Comparing intermaxillary fixation with screws or arch bar. A randomised clinical trial.

PubMed

van den Bergh, B; Blankestijn, J; van der Ploeg, T; Tuinzing, D B; Forouzanfar, T

2015-06-01

A mandibular condyle fracture can be treated conservatively by intermaxillary fixation (IMF) or by open reposition and internal fixation (ORIF). Many IMF-modalities can be chosen, including IMF-screws (IMFS). This prospective multi-centre randomised clinical trial compared the use of IMFS with the use of arch bars in the treatment of mandibular condyle fractures. The study population consisted of 50 patients (mean age: 31.8 years). Twenty-four (48%) patients were allocated in the IMFS group. Twenty-six (52%) patients were assigned to the arch bars group. In total 188 IMF-screws were used (5-12 screws per patient, mean 7.83 screws per patient). All pain scores were lower in the IMFS group. Three patients developed a malocclusion (IFMS-group: one patient, arch bars-group: two patients). Mean surgical time was significantly shorter in the IMFS group (59 vs. 126 min; p<0.001). There were no needlestick injuries (0%) in the IMFS group and eight (30.7%) in the arch bars group (p=0.003). One IMF-screw fractured on insertion (0.53%), one (0.53%) screw was inserted into a root. Six (3.2%) screws loosened spontaneously in four patients. Mucosal disturbances were seen in 22 patients, equally divided over both groups. Considering the advantages and the disadvantages of IMFS, and observing the results of this study, the authors conclude that IMFS provide a superior method for IMF. IMFS are safer for the patients and surgeons. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

A cannabinoid 2 receptor agonist attenuates bone cancer-induced pain and bone loss

PubMed Central

Lozano, Alysia; Wright, Courtney; Vardanyan, Anna; King, Tamara; Largent-Milnes, Tally M.; Nelson, Mark; Jimenez-Andrade, Juan Miguel; Mantyh, Patrick W; Vanderah, Todd W.

2010-01-01

Aims Cannabinoid CB2 agonists have been shown to alleviate behavioral signs of inflammatory and neuropathic pain in animal models. AM1241, a CB2 agonist, does not demonstrate central nervous system side-effects seen with CB1 agonists such as hypothermia and catalepsy. Metastatic bone cancer causes severe pain in patients and is treated with analgesics such as opiates. Recent reports suggest that sustained opiates can produce paradoxical hyperalgesic actions and enhance bone destruction in a murine model of bone cancer. In contrast, CB2 selective agonists have been shown to reduce bone loss associated with a model of osteoporosis. Here we tested whether a CB2 agonist administered over a 7 day period inhibits bone cancer-induced pain as well as attenuates cancer-induced bone degradation. Main Methods A murine bone cancer model was used in which osteolytic sarcoma cells were injected into the intramedullary space of the distal end of the femur. Behavioral and radiographic image analysis was performed at days 7, 10 and 14 after injection of tumor cells into the femur. Key Findings Osteolytic sarcoma within the femur produced spontaneous and touch evoked behavioral signs of pain within the tumor-bearing limb. The systemic administration of AM1241 acutely or for 7 days significantly attenuated spontaneous and evoked pain in the inoculated limb. Sustained AM1241 significantly reduced bone loss and decreased the incidence of cancer-induced bone fractures. Significance These findings suggest a novel therapy for cancer-induced bone pain, bone loss and bone fracture while lacking many unwanted side effects seen with current treatments for bone cancer pain. PMID:20176037

Possible delayed respiratory depression following intrathecal injection of morphine and bupivacaine in an alpaca.

PubMed

Martínez, Miguel; Murison, Pamela J; Murrell, Jo

2014-01-01

To describe general anesthesia and successful treatment of an alpaca, which developed respiratory arrest 2 hours after intrathecal injection of morphine and bupivacaine. A 10-day-old female alpaca weighing 7.3 kg was presented to our hospital with a fractured right tibia. The cria was anesthetized to repair the fracture with a dynamic compression plate. Anesthesia was induced with IV propofol and maintained with sevoflurane in 100% oxygen. Prior to the start of surgery the alpaca received an unintended intrathecal injection of 0.6 mL of a solution of 0.5 mg morphine (0.068 mg/kg) and 1.5 mg bupivacaine (0.2 mg/kg), after an attempted lumbo-sacral epidural. The alpaca developed respiratory arrest 120 minutes after the intrathecal injection was administered. Adequate hemoglobin-oxygen saturation was maintained despite minimal intermittent manual ventilation, but marked hypercapnia developed (PaCO2 of 17.3 KPa [130 mm Hg]). Delayed respiratory depression resulting from cephalad migration of intrathecal morphine was suspected. Ventilation was supported until the end of surgery when sevoflurane was discontinued. The trachea remained intubated, 100% oxygen was supplied, and ventilation was supported at 2-4 breaths/min for the next 60 minutes, but no attempts to breathe spontaneously were detected. Intravenous naloxone (0.3 mg [0.04 mg/kg]) was administered slowly to effect until adequate spontaneous ventilation and full consciousness returned. The anesthetic recovery of the alpaca was rapid and uneventful after the opioid antagonist was given. Delayed respiratory depression is a potential complication after intrathecal administration of morphine. Careful dose-adjustment may reduce the risk, and close monitoring will result in early detection and treatment of this complication. © Veterinary Emergency and Critical Care Society 2014.

Label-free Raman spectroscopy provides early determination and precise localization of breast cancer-colonized bone alterations† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7sc02905e

PubMed Central

Zhang, Chi; Winnard Jr, Paul T.; Dasari, Sidarth; Kominsky, Scott L.; Doucet, Michele; Jayaraman, Swaathi

2017-01-01

Breast neoplasms frequently colonize bone and induce development of osteolytic bone lesions by disrupting the homeostasis of the bone microenvironment. This degenerative process can lead to bone pain and pathological bone fracture, a major cause of cancer morbidity and diminished quality of life, which is exacerbated by our limited ability to monitor early metastatic disease in bone and assess fracture risk. Spurred by its label-free, real-time nature and its exquisite molecular specificity, we employed spontaneous Raman spectroscopy to assess and quantify early metastasis driven biochemical alterations to bone composition. As early as two weeks after intracardiac inoculations of MDA-MB-435 breast cancer cells in NOD-SCID mice, Raman spectroscopic measurements in the femur and spine revealed consistent changes in carbonate substitution, overall mineralization as well as crystallinity increase in tumor-bearing bones when compared with their normal counterparts. Our observations reveal the possibility of early stage detection of biochemical changes in the tumor-bearing bones – significantly before morphological variations are captured through radiographic diagnosis. This study paves the way for a better molecular understanding of altered bone remodeling in such metastatic niches, and for further clinical studies with the goal of establishing a non-invasive tool for early metastasis detection and prediction of pathological fracture risk in breast cancer. PMID:29629144

Large bowel obstruction due to gallstones: an endoscopic problem?

PubMed Central

Waterland, Peter; Khan, Faisal Shehzaad; Durkin, Damien

2014-01-01

A 73-year-old man was admitted with symptoms of large bowel obstruction. An emergency CT scan revealed pneumobilia and large bowel obstruction at the level of the rectosigmoid due to a 4×4 cm impacted gallstone. Flexible sigmoidoscopy confirmed the diagnosis but initial attempts to drag the stone into the rectum failed. An endoscopic mechanical lithotripter was employed to repeatedly fracture the gallstone into smaller fragments, which were passed spontaneously the next day. The patient made a complete recovery avoiding the potential dangers of surgery. This case report discusses cholecystoenteric fistula and a novel minimally invasive treatment for large bowel obstruction due to gallstones. PMID:24390966

Large bowel obstruction due to gallstones: an endoscopic problem?

PubMed

Waterland, Peter; Khan, Faisal Shehzaad; Durkin, Damien

2014-01-03

A 73-year-old man was admitted with symptoms of large bowel obstruction. An emergency CT scan revealed pneumobilia and large bowel obstruction at the level of the rectosigmoid due to a 4×4 cm impacted gallstone. Flexible sigmoidoscopy confirmed the diagnosis but initial attempts to drag the stone into the rectum failed. An endoscopic mechanical lithotripter was employed to repeatedly fracture the gallstone into smaller fragments, which were passed spontaneously the next day. The patient made a complete recovery avoiding the potential dangers of surgery. This case report discusses cholecystoenteric fistula and a novel minimally invasive treatment for large bowel obstruction due to gallstones.

Progress of the LASL dry hot rock geothermal energy project

NASA Technical Reports Server (NTRS)

Smith, M. C.

1974-01-01

The possibilities and problems of extracting energy from geothermal reservoirs which do not spontaneously yield useful amounts of steam or hot water are discussed. The system for accomplishing this which is being developed first is a pressurized-water circulation loop intended for use in relatively impermeable hot rock. It will consist of two holes connected through the hot rock by a very large hydraulic fracture and connected at the surface through the primary heat exchanger of an energy utilization system. Preliminary experiments in a hole 2576 ft (0.7852 km) deep, extending about 470 ft (143 m) into the Precambrian basement rock underlying the Jemez Plateau of north-central New Mexico, revealed no unexpected difficulties in drilling or hydraulically fracturing such rock at a temperature of approximately 100 C, and demonstrated a permeability low enough so that it appeared probable that pressurized water could be contained by the basement rock. Similar experiments are in progress in a second hole, now 6701 ft (2.043 km) deep, about 1.5 miles (2.4 km) south of the first one.

Transient regional osteoporosis.

PubMed

Cano-Marquina, Antonio; Tarín, Juan J; García-Pérez, Miguel-Ángel; Cano, Antonio

2014-04-01

Transient regional osteoporosis (TRO) is a disease that predisposes to fragility fracture in weight bearing joints of mid-life women and men. Pregnant women may also suffer the process, usually at the hip. The prevalence of TRO is lower than the systemic form, associated with postmenopause and advanced age, but may be falsely diminished by under-diagnosis. The disease may be uni- or bilateral, and may migrate to distinct joints. One main feature of TRO is spontaneous recovery. Pain and progressive limitation in the functionality of the affected joint(s) are key symptoms. In the case of the form associated with pregnancy, difficulties in diagnosis derive from the relatively young age at presentation and from the clinical overlapping with the frequent aches during gestation. Densitometric osteoporosis in the affected region is not always present, but bone marrow edema, with or without joint effusion, is detected by magnetic resonance. There are not treatment guidelines, but the association of antiresorptives to symptomatic treatment seems to be beneficial. Surgery or other orthopedic interventions can be required for specific indications, like hip fracture, intra-medullary decompression, or other. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A case off the bell curve: customization of the dialysis prescription--a self-report.

PubMed

Weintraub, Judy

2013-01-01

In a 35+-year dialysis patient, a series of spontaneous fractures and a history of severe somatic pains of unknown origin, superimposed on a history of generally adequate laboratory values, prompted an attempt at diagnosis of the cause of the condition. The patient was on a regimen of nocturnal home hemodialysis, a 4-night, 7-hour treatment. Physicians were divided on whether the cause might be neuropathic, muscular or osteopathic. A bone biopsy was conducted to evaluate the integrity of the bones. The biopsy resulted in a diagnosis of osteomalacia - severe mineral depletion of the skeletal system. This was surprising because the hematologic laboratory values did not seem to indicate this. The calcium level in the dialysate was greatly increased, which was supplemented by moderate inclusion of sodium phosphate. The bones strengthened over time, resulting in no further fractures, an easing of general pain, and significantly improved mobility. The results demonstrate that customization of the dialysis prescription should be readily available for hemodialysis, whether treated in-center or at home. © 2013 S. Karger AG, Basel.

Structure of the cell envelope of corynebacteria: importance of the non-covalently bound lipids in the formation of the cell wall permeability barrier and fracture plane.

PubMed

Puech, V; Chami, M; Lemassu, A; Lanéelle, M A; Schiffler, B; Gounon, P; Bayan, N; Benz, R; Daffé, M

2001-05-01

With the recent success of the heterologous expression of mycobacterial antigens in corynebacteria, in addition to the importance of these bacteria in biotechnology and medicine, a better understanding of the structure of their cell envelopes was needed. A combination of molecular compositional analysis, ultrastructural appearance and freeze-etch electron microscopy study was used to arrive at a chemical model, unique to corynebacteria but consistent with their phylogenetic relatedness to mycobacteria and other members of the distinctive suprageneric actinomycete taxon. Transmission electron microscopy and chemical analyses showed that the cell envelopes of the representative strains of corynebacteria examined consisted of (i) an outer layer composed of polysaccharides (primarily a high-molecular-mass glucan and arabinomannans), proteins, which include the mycoloyltransferase PS1, and lipids; (ii) a cell wall glycan core of peptidoglycan-arabinogalactan which may contain other sugar residues and was usually esterified by corynomycolic acids; and (iii) a typical plasma membrane bilayer. Freeze-etch electron microscopy showed that most corynomycolate-containing strains exhibited a main fracture plane in their cell wall and contained low-molecular-mass porins, while the fracture occurred within the plasma membrane of strains devoid of both corynomycolate and pore-forming proteins. Importantly, in most strains, the amount of cell wall-linked corynomycolates was not sufficient to cover the bacterial surface; interestingly, the occurrence of a cell wall fracture plane correlated with the amount of non-covalently bound lipids of the strains. Furthermore, these lipids were shown to spontaneously form liposomes, indicating that they may participate in a bilayer structure. Altogether, the data suggested that the cell wall permeability barrier in corynebacteria involved both covalently linked corynomycolates and non-covalently bound lipids of their cell envelopes.

Assessment of a press-fit proximal femoral modular reconstruction implant (PFMR®) at 14.5 years. A 48-case series with a disturbing rate of implant fracture.

PubMed

Dumoulin, Q; Sabau, S; Goetzmann, T; Jacquot, A; Sirveaux, F; Mole, D; Roche, O

2018-05-01

The PFMR ® proximal femoral modular reconstruction implant (Protek, Sulzer Orthopedics, Switzerland) is a straight modular stem in sanded titanium with press-fit anchorage, intended to achieve spontaneous bone reconstruction following Wagner's principle. The aim of the present study was to analyze long-term clinical and radiological outcome. A single-center retrospective study included 48 PFMR stems implanted in 47 patients between 1998 and 2002. Results in this series were previously reported at 7 years' follow-up. Clinical assessment used PMA and Harris scores. Radiologic assessment focused on stem stability and osseointegration, and bone stock following Le Béguec. Twenty-three patients were seen at a mean 14.5 years' follow-up (13 deceased, 11 lost to follow-up), including 1 with bilateral implants, i.e., 24 stems. PMA and Harris scores, stem stability and osseointegration and bone stock were stable with respect to the 7-year findings. Radiology found 7 stem fractures in the Morse taper, i.e., in 29% of implants. Two of these cases required femoral implant replacement; 5 were asymptomatic. Long-term outcome for PFMR stems was clinically and radiologically satisfactory for the 16 patients free of mechanical complications. The Morse taper fracture rate was high, and higher than reported elsewhere. The usual risk factors for implant fracture were not found in the present series. The modular design of the press-fit revision implant is its weak point; monoblock implants should be used in patients with good life-expectancy. IV (retrospective study). Copyright © 2018 Elsevier Masson SAS. All rights reserved.

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

Preauricular transmasseteric anteroparotid approach for extracorporeal fixation of mandibular condyle fractures.

PubMed

Gali, Rajasekhar; Devireddy, Sathya Kumar; Venkata, Kishore Kumar Rayadurgam; Kanubaddy, Sridhar Reddy; Nemaly, Chaithanyaa; Dasari, Mallikarjuna

2016-01-01

Free grafting or extracorporeal fixation of traumatically displaced mandibular condyles is sometimes required in patients with severe anteromedial displacement of condylar head. Majority of the published studies report the use of a submandibular, retromandibular or preauricular incisions for the access which have demerits of limited visibility, access and potential to cause damage to facial nerve and other parotid gland related complications. This retrospective clinical case record study was done to evaluate the preauricular transmasseteric anteroparotid (P-TMAP) approach for open reduction and extracorporeal fixation of displaced and dislocated high condylar fractures of the mandible. This retrospective study involved search of clinical case records of seven patients with displaced and dislocated high condylar fractures treated by open reduction and extracorporeal fixation over a 3-year period. The parameters assessed were as follows: a) the ease of access for retrieval, reimplantation and fixation of the proximal segment; b) the postoperative approach related complications; c) the adequacy of anatomical reduction and stability of fixation; d) the occlusal changes; and the e) TMJ function and radiological changes. Accessibility and visibility were good. Accurate anatomical reduction and fixation were achieved in all the patients. The recorded complications were minimal and transient. Facial nerve (buccal branch) palsy was noted in one patient with spontaneous resolution within 3 months. No cases of sialocele or Frey's syndrome were seen. The P-TMAP approach provides good access for open reduction and extracorporeal fixation of severely displaced condylar fractures. It facilitates retrieval, transplantation, repositioning, fixing the condyle and also reduces the chances of requirement of a vertical ramus osteotomy. It gives straight-line access to condylar head and ramus thereby permitting perpendicular placement of screws with minimal risk of damage to the facial nerve.

Preauricular transmasseteric anteroparotid approach for extracorporeal fixation of mandibular condyle fractures

PubMed Central

Gali, Rajasekhar; Devireddy, Sathya Kumar; Venkata, Kishore Kumar Rayadurgam; Kanubaddy, Sridhar Reddy; Nemaly, Chaithanyaa; Dasari, Mallikarjuna

2016-01-01

Introduction: Free grafting or extracorporeal fixation of traumatically displaced mandibular condyles is sometimes required in patients with severe anteromedial displacement of condylar head. Majority of the published studies report the use of a submandibular, retromandibular or preauricular incisions for the access which have demerits of limited visibility, access and potential to cause damage to facial nerve and other parotid gland related complications. Purpose: This retrospective clinical case record study was done to evaluate the preauricular transmasseteric anteroparotid (P-TMAP) approach for open reduction and extracorporeal fixation of displaced and dislocated high condylar fractures of the mandible. Patients and Methods: This retrospective study involved search of clinical case records of seven patients with displaced and dislocated high condylar fractures treated by open reduction and extracorporeal fixation over a 3-year period. The parameters assessed were as follows: a) the ease of access for retrieval, reimplantation and fixation of the proximal segment; b) the postoperative approach related complications; c) the adequacy of anatomical reduction and stability of fixation; d) the occlusal changes; and the e) TMJ function and radiological changes. Results: Accessibility and visibility were good. Accurate anatomical reduction and fixation were achieved in all the patients. The recorded complications were minimal and transient. Facial nerve (buccal branch) palsy was noted in one patient with spontaneous resolution within 3 months. No cases of sialocele or Frey's syndrome were seen. Conclusion: The P-TMAP approach provides good access for open reduction and extracorporeal fixation of severely displaced condylar fractures. It facilitates retrieval, transplantation, repositioning, fixing the condyle and also reduces the chances of requirement of a vertical ramus osteotomy. It gives straight-line access to condylar head and ramus thereby permitting perpendicular placement of screws with minimal risk of damage to the facial nerve. PMID:27274123

Dynamical Instability Produces Transform Faults at Mid-Ocean Ridges

NASA Astrophysics Data System (ADS)

Gerya, Taras

2010-08-01

Transform faults at mid-ocean ridges—one of the most striking, yet enigmatic features of terrestrial plate tectonics—are considered to be the inherited product of preexisting fault structures. Ridge offsets along these faults therefore should remain constant with time. Here, numerical models suggest that transform faults are actively developing and result from dynamical instability of constructive plate boundaries, irrespective of previous structure. Boundary instability from asymmetric plate growth can spontaneously start in alternate directions along successive ridge sections; the resultant curved ridges become transform faults within a few million years. Fracture-related rheological weakening stabilizes ridge-parallel detachment faults. Offsets along the transform faults change continuously with time by asymmetric plate growth and discontinuously by ridge jumps.

Nephrotic-range proteinuria and interstitial nephritis associated with the use of a topical loxoprofen patch.

PubMed

Kikuchi, Hiroaki; Aoyagi, Makoto; Nagahama, Kiyotaka; Yajima, Yu; Yamamura, Chisato; Arai, Yohei; Hirasawa, Suguru; Aki, Shota; Inaba, Naoto; Tanaka, Hiroyuki; Tamura, Teiichi

2014-01-01

A 76-year-old woman with a history of lumbar fracture and marked proteinuria, bilateral pitting edema, malaise and pruritus was referred for an evaluation of an impaired renal function. A renal biopsy led to a tentative diagnosis of acute interstitial nephritis (AIN) with minimal change disease caused by nonsteroidal anti-inflammatory drugs (NSAIDs). Following the discontinuation of oral NSAIDs, the patient's symptoms disappeared spontaneously. However, nephrotic-range proteinuria relapsed one month after discharge, following loxoprofen patch use. The withdrawal of the topical loxoprofen patches once again resulted in the disappearance of all symptoms. This is the first case report of nephrotic-range proteinuria and AIN secondary to topical NSAID patch use.

Spontaneous Cracking in Unfired Magnesia Compacts Upon Standing in Air

NASA Technical Reports Server (NTRS)

Davies, Myron O.; Grimes, Hubert H.; May, Charles E.

1961-01-01

Analytical-grade magnesium oxide powder without binder was compressed hydrostatically to 50,000 lb. per sq. in. to form compacts. When exposed to moist air immediately after pressing, these compacts developed irregularly shaped cracks. Controlled tests, in which these compacts were exposed for various lengths of time to various atmospheres, indicated that in general water vapor, carbon dioxide, and residual stresses had to be present if cracking was to occur. The probable cause of the cracking was the formation of a less dense and mechanically weak basic carbonate of magnesium at crystallite surface points of high stress concentration which developed during the compacting. The adsorption of dry CO2 at such sites prevented subsequent delayed fracture.

Osseous adaptation to continuous loading of rigid endosseous implants

NASA Technical Reports Server (NTRS)

Roberts, W. E.; Smith, R. K.; Mozsary, P. G.; Zilberman, Y.; Smith, R. S.

1984-01-01

The effect of loading on etched Ti implants in the femurs of young (3 mo) and adult (6 mo) rabbits is investigated experimentally. The results are presented in photographs, fluorescence and polarization micrographs, radiographs, and drawings and discussed. Implantation is followed by formation of coarse woven bone within 3 d and mature lamellar bone by 6 wks, with nonspecific subperiosteal bony hypertrophy in the young rabbits only. Spring loading at 100 g produces spontaneous spiral-type fractures when applied immediately, but the implants remain rigid when loads are applied after 6-12 wks of healing. The mechanisms of bone formation involved are examined, and the potential of endosseous implants as anchors in orthodontics or dentofacial-orthopedics is confirmed.

Osteoporosis in pregnancy: more than postural backache.

PubMed

Topping, J; Black, A J; Farquharson, R G; Fraser, W D

1998-01-01

Though uncommon, osteoporosis can occur in pregnancy or shortly after delivery. The most common feature is back pain, often severely disabling. Suspect osteoporosis if pain of sudden onset in the upper lumbar or thoracic spine is not relieved by simple analgesia, or if there is a noticeable loss of height. X-rays reveal low bone density and fractures of the vertebrae. 70% of cases occur in first pregnancies. Recurrence is unusual. Most cases resolve spontaneously; a minority cause disability lasting months or years. If osteoporosis is diagnosed, breast feeding should be discouraged because of its effect on bone mineral density. Anyone who has had osteoporosis of pregnancy is at risk of postmenopausal osteoporosis and should take medical advice.

Viscoelastic Fracturing As a Migration and Expulsion Mechanism for Hydrocarbons in Shales: Analog Experiments

NASA Astrophysics Data System (ADS)

Van Damme, H.

2014-12-01

We report the results of simple laboratory experiments aimed at mimicking the generation, migration, and expulsion process of oil or gas from soft clayey sediments, triggered by thermal decomposition of organic matter. In previously published work, we showed that the injection of fluids into a soft sediment layer confined within a quasi-2D Hele-Shaw cell led to the transition from a viscous fingering invasion regime to a viscoelastic fracturing regime. The transition is controlled by the ratio of the characteristic times for the invasion process and for the structural relaxation in the sediment, respectively (Deborah number). Here we show that expulsion is a discontinuous quasi-periodic process, driven by the elastic energy stored in the embedding layers. We report also about two sets of experiments aimed at understanding the conditions in which fluid generation from multiple sources can generate a highly connected network of fractures for expulsion. In a first set of experiments, a Hele-Shaw cell with multiple injection points and multiple outlets was used. It is shown that, due to attractive elastic interactions between cracks, a network spontaneously forms as soon as invasion proceeds in the viscoelastic regime. On the contrary, no network of migration paths is forming in the viscous fingering regime, due to the effective repulsion of the fluid channels. In the second set of analog experiments, we used a thermostated mini-Hele-Shaw cell, the gap of which was filled with a strong clay mud in which microcrystals of reactive organic matter (azoisobutyronitrile, AIBN) are dispersed, or with a mud prepared with clay particles on which the organic matter was pre-impregnated. AIBN decomposes around 70°C, releasing nitrogen gas. It was again observed that, depending on the viscoelastic properties of the clay matrix, gas evolution occurs either by formation and coalescence of bubbles, or by formation of a percolating network of fractures. The length of the fracture network is initially linearly related to the Total (reactive) Organic Matter content. The expulsion process is remarkably effective in the fracturing regime (close to 100 percent), even at vey low TOC (below 0.5 percent). The relevance of these experiments for oil and gas migration in natural conditions will be discussed.

Self-Sustained Mode-3 Tear Controls Dynamics of Narrow Retreating Subduction Zones

NASA Astrophysics Data System (ADS)

Munch, J.; Gerya, T.; Ueda, K.

2017-12-01

The Caribbean oroclinal basin exhibits several narrow retreating slabs in an oceanic domain. The slabs show a curved shape associated to a bent topography (trench). We propose that the curvature of the topography depends on slab retreat mechanisms following mode-3 tearing at the edges of the slab (out of the plane fracture propagation). While first-order characteristics have been principally reproduced in self-sustained subduction initiation models (Gerya et al., 2015, Nature, 527, 221-225), the relevant observations have not been quantified and the exact mechanism is not understood. In this work, we study the long-term 3D evolution of narrowing oceanic subduction zones during retreat, and investigate the link between mode-3 tear and orocline formation. Numerical experiments are carried out with a thermo-mechanical 3D finite-difference code. To allow the observation of developing topography, the precise location of the internal surface and its evolution by material diffusion is tracked. Retreating subduction is facilitated via a strong age contrast between a young lithosphere window enclosed by shear zones and the surrounding lithosphere. By varying the length and thickness of the shear zones and location of the age transition, the influence of these parameters on the tearing process and the development of topography is assessed. Experiments trigger subduction initiation and slab retreat via fracture zone collapse and spontaneous paired mode-3 tear propagation within the oceanic plate interior. Narrow retreating subducting slabs form as a natural result of the spontaneous paired tearing process. A curved trench forms along with slab retreat. Topography evolution and tearing trajectory appear to be dependent on the initial shear zones and young window dimensions. We also note a strong narrowing of the slab during the retreat (several tens of kilometers over 800 km of retreat). Overall, results indicate that narrowing of retreating slabs is a self-consistent consequence of tear propagation dynamics. This plate tearing mechanism may control dynamics of other narrow retreating subduction zones worldwide.

Algodystrophy (CRPS) in minor orthopedic surgery.

PubMed

Corradini, Costantino; Bosizio, Claudia; Moretti, Antimo

2015-01-01

Algodystrophy or Chronic Regional Pain Syndrome (CRPS) is a painful disorder that develops especially at upper or lower extremities of the limbs after a fracture. This syndrome is probably due to bone microvascular changes with subsequent sympathetic nervous system involvement. The pain that characterizes CRPS is spontaneous, disproportionate to the traumatic event and is associated with hyperalgesia, and a variety of autonomic and trophic disorders. This condition has a variable incidence up to 37% of the cases, increasing along with the severity of the fracture. CRPS has a higher chance of developing in women, in older individuals, in smokers, and in patients with reduced bone strength. Early diagnosis is associated with remission in 80-90% of cases. Since the typical onset of the disease is insidious over 2 weeks after surgery, a diagnostic and therapeutic delay may occur. These are the major causes of a high percentage of chronic and disabling complications leading to impaired functional outcomes. In the acute or subacute phase, infusion of bisphosphonates has proven to be the first-choice of treatment with a high percentage of remissions. Moreover, it has been suggested the utility of vitamin C in prevention of CRPS. Furthermore, in the chronic phase electroanalgesia seems to provide promising results.

MRI of inflammatory spondyloarthropathy following traumatic cauda equina syndrome.

PubMed

Ginder, L M; Porter, N A; Subedi, N; Singh, J; Lalam, R K; Tins, B J; Tyrrell, P N M; Osman, A; Cassar-Pullicino, V N

2015-03-01

Spondyloarthropathy has been described radiographically in patients following paralysis from spinal cord trauma. Onset of these findings after cauda equina syndrome have not been reported previously. Furthermore, the magnetic resonance documentation of its early evolution has not been recorded. We report a case of early-onset spondyloarthropathy shown by magnetic resonance imaging (MRI) in a patient with cauda equina syndrome due to bilateral sacral insufficiency fractures. Unique case study review, one case. Review of the clinical case notes and imaging including initial and subsequent MR imaging. The initial MRI of the lumbosacral spine showed bilateral sacral insufficiency fractures with a kyphotic deformity. The vertebral bodies were normal on the initial computed tomography and MRI studies, which did not reveal pre-existing features of sacroiliitis. The second MRI performed 5 months later clearly showed spondylitis at multiple vertebral levels with partial resolution 18 months post injury. Spondyloarthropathy in patients with paralysis due to spinal cord injury is well documented in the English language literature, but until now this has not been demonstrated by MRI. It is a rare complication of traumatic cauda equina syndrome that commences soon after the traumatic event and can resolve spontaneously.

[Intra-alveolar hemorrhage: rare presentation of fat pulmonary embolism].

PubMed

Ketata, W; Msaad, S; Bahloul, N; Marouen, F; Ayoub, A

2010-11-01

Fat embolism syndrome is a severe complication of long bone fractures, corresponding to the obstruction of small vessels by microdroplets of fat, originating from medulla ossium. Pulmonary involvement, present in 90% cases, makes the severity of the disease. We report the case of a 22-year-old man who presented, two days after industrial accident causing an opened tibial fracture, acute dyspnea with hemoptysis. Angio-CT-scan didn't show any proximal vascular obstruction, but parenchymal sections showed diffuse, bilateral and multifocal hyperdensities predominating at the periphery. Broncho-alveolar lavage brought a hemorrhagic liquid, with a high macrophage content and lipid inclusions in macrophages. Exams for the etiologic diagnosis of intra-alveolar hemorrhage were negative: renal function, 24-hour proteinuria, antinuclear antibodies, antineutrophil cytoplasmic antibodies. The diagnosis of intra-alveolar hemorrhage secondary to fat embolism was established. The outcome was spontaneously favorable. The occurrence of intra-alveolar hemorrhage in the course fat embolism is rarely reported. Its pathogenic mechanisms are not understood. It is mandatory to eliminate the other causes of alveolar hemorrhage before holding the diagnosis of fat embolism. Treatment is only symptomatic, based on respiratory reanimation. Copyright © 2010 SPLF. Published by Elsevier Masson SAS. All rights reserved.

Spontaneous regression of retro-odontoid post traumatic cicatrix following occipitocervical fixation.

PubMed

Sinha, Priyank; Lee, Ming-Te; Panbehchi, Sasan; Saxena, Ankur; Pal, Debasish

2017-01-01

This case report describes a patient who presented with myelopathy secondary to a large retro-odontoid post traumatic cicatrix. The objective of this study was to discuss the clinical presentation, pathogenesis, imaging, and surgical management of pseudoarthrosis tissue mass associated with odontoid nonunion. Atlantoaxial subluxation (AAS) has been widely reported in patients with rheumatoid arthritis. AAS leads to repeated cycles of partial tear and repair of ligaments around the altantoaxial complex, resulting in the formation of periodontoid mass (pseudotumor). It is thought that formation of retro-odontoid post traumatic mass (cicatrix), in certain cases of odontoid fracture, is because of similar pathology. This is a retrospective review of case note. Here, the patient underwent posterior decompression through a C1-C2 laminectomy and occipitocervical (C0-C4) fusion with instrumentation, which resulted in dramatic improvement in his symptoms and spontaneous regression of retro-odontoid post traumatic cicatrix. We have described an interesting and a rare case of a large pseudoarthrosis tissue mass associated with odontoid nonunion, which regressed following stand-alone posterior instrumentation. To the best of our knowledge, only a handful of such cases of spontaneous regression of retro-odontoid post traumatic cicatrix following occipitocervical fixation have been described in literature, and our case adds to the growing list of such cases and may help in understanding the natural history of the disease process one day. Although rare, post traumatic cicatrix should be considered as a differential diagnosis of enhancing retro-odontoid mass, especially if there is any history of cervical spine trauma.

Bone cysts: unicameral and aneurysmal bone cyst.

PubMed

Mascard, E; Gomez-Brouchet, A; Lambot, K

2015-02-01

Simple and aneurysmal bone cysts are benign lytic bone lesions, usually encountered in children and adolescents. Simple bone cyst is a cystic, fluid-filled lesion, which may be unicameral (UBC) or partially separated. UBC can involve all bones, but usually the long bone metaphysis and otherwise primarily the proximal humerus and proximal femur. The classic aneurysmal bone cyst (ABC) is an expansive and hemorrhagic tumor, usually showing characteristic translocation. About 30% of ABCs are secondary, without translocation; they occur in reaction to another, usually benign, bone lesion. ABCs are metaphyseal, excentric, bulging, fluid-filled and multicameral, and may develop in all bones of the skeleton. On MRI, the fluid level is evocative. It is mandatory to distinguish ABC from UBC, as prognosis and treatment are different. UBCs resolve spontaneously between adolescence and adulthood; the main concern is the risk of pathologic fracture. Treatment in non-threatening forms consists in intracystic injection of methylprednisolone. When there is a risk of fracture, especially of the femoral neck, surgery with curettage, filling with bone substitute or graft and osteosynthesis may be required. ABCs are potentially more aggressive, with a risk of bone destruction. Diagnosis must systematically be confirmed by biopsy, identifying soft-tissue parts, as telangiectatic sarcoma can mimic ABC. Intra-lesional sclerotherapy with alcohol is an effective treatment. In spinal ABC and in aggressive lesions with a risk of fracture, surgical treatment should be preferred, possibly after preoperative embolization. The risk of malignant transformation is very low, except in case of radiation therapy. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Thoracolumbar spine loading associated with kinematics of the young and the elderly during activities of daily living.

PubMed

Ignasiak, Dominika; Rüeger, Andrea; Sperr, Ramona; Ferguson, Stephen J

2018-03-21

Excessive mechanical loading of the spine is a critical factor in vertebral fracture initiation. Most vertebral fractures develop spontaneously or due to mild trauma, as physiological loads during activities of daily living might exceed the failure load of osteoporotic vertebra. Spinal loading patterns are affected by vertebral kinematics, which differ between elderly and young individuals. In this study, the effects of age-related changes in spine kinematics on thoracolumbar spinal segmental loading during dynamic activities of daily living were investigated using combined experimental and modeling approach. Forty-four healthy volunteers were recruited into two age groups: young (N = 23, age = 27.1 ± 3.8) and elderly (N = 21, age = 70.1 ± 3.9). The spinal curvature was assessed with a skin-surface device and the kinematics of the spine and lower extremities were recorded during daily living tasks (flexion-extension and stand-sit-stand) with a motion capture system. The obtained data were used as input for a musculoskeletal model with a detailed thoracolumbar spine representation. To isolate the effect of kinematics on predicted loads, other model properties were kept constant. Inverse dynamics simulations were performed in the AnyBody Modeling System to estimate corresponding spinal loads. The maximum compressive loads predicted for the elderly motion patterns were lower than those of the young for L2/L3 and L3/L4 lumbar levels during flexion and for upper thoracic levels during stand-to-sit (T1/T2-T8/T9) and sit-to-stand (T3/T4-T6/T7). However, the maximum loads predicted for the lower thoracic levels (T9/T10-L1/L2), a common site of vertebral fractures, were similar compared to the young. Nevertheless, these loads acting on the vertebrae of reduced bone quality might contribute to a higher fracture risk for the elderly. Copyright © 2017 Elsevier Ltd. All rights reserved.

Myogenic progenitors contribute to open but not closed fracture repair.

PubMed

Liu, Renjing; Birke, Oliver; Morse, Alyson; Peacock, Lauren; Mikulec, Kathy; Little, David G; Schindeler, Aaron

2011-12-22

Bone repair is dependent on the presence of osteocompetent progenitors that are able to differentiate and generate new bone. Muscle is found in close association with orthopaedic injury, however its capacity to make a cellular contribution to bone repair remains ambiguous. We hypothesized that myogenic cells of the MyoD-lineage are able to contribute to bone repair. We employed a MyoD-Cre+:Z/AP+ conditional reporter mouse in which all cells of the MyoD-lineage are permanently labeled with a human alkaline phosphatase (hAP) reporter. We tracked the contribution of MyoD-lineage cells in mouse models of tibial bone healing. In the absence of musculoskeletal trauma, MyoD-expressing cells are limited to skeletal muscle and the presence of reporter-positive cells in non-muscle tissues is negligible. In a closed tibial fracture model, there was no significant contribution of hAP+ cells to the healing callus. In contrast, open tibial fractures featuring periosteal stripping and muscle fenestration had up to 50% of hAP+ cells detected in the open fracture callus. At early stages of repair, many hAP+ cells exhibited a chondrocyte morphology, with lesser numbers of osteoblast-like hAP+ cells present at the later stages. Serial sections stained for hAP and type II and type I collagen showed that MyoD-lineage cells were surrounded by cartilaginous or bony matrix, suggestive of a functional role in the repair process. To exclude the prospect that osteoprogenitors spontaneously express MyoD during bone repair, we created a metaphyseal drill hole defect in the tibia. No hAP+ staining was observed in this model suggesting that the expression of MyoD is not a normal event for endogenous osteoprogenitors. These data document for the first time that muscle cells can play a significant secondary role in bone repair and this knowledge may lead to important translational applications in orthopaedic surgery. Please see related article: http://www.biomedcentral.com/1741-7015/9/136.

Competition of wormholes during the evolution of cave passages

NASA Astrophysics Data System (ADS)

Gabrovsek, Franci; Dreybrodt, Wolfgang

2017-04-01

Reactive fronts in two-dimensional plane parallel fractures, with constant head difference between input and output and with diffusion controlled first order reaction rates R = keff ṡ (Ceq - C), where keff = k ṡ (1 + ka/6D)-1, are instable to infinitesimal perturbations in fracture aperture width (1), causing spontaneous fingering of the reactive front resulting in the formation of wormholes. C is the actual concentration and Ceq the equilibrium concentration, a, is the actual aperture width of the fracture , and D the constant of molecular diffusion. Fingering happens also in plane-parallel rough fractures where it is triggered by the existence of statistically more favorable pathways. The same behavior is observed in rectangular two-dimensional networks of "one-dimensional" smooth fractures used in modeling the evolution of caves in soluble rock (2). Here the formation of caves can be regarded as the evolution of wormholes along the two-dimensional network. Once fingering has been triggered, either by instability or by roughness, many small fingers compete with each other and only a few survive. Here we investigate the competition between two seeded fingers in initially homogeneous fracture networks with identical aperture width of all fractures and also in inhomogeneous ones where the aperture widths are distributed log normally. In both cases our modeling reveals the rules of competition: By instability one of the fingers grows faster than its competitor therefore penetrating somewhat deeper. As a consequence the hydraulic head at its tip is higher than that close to the tip of the shorter finger. Therefore the fractures connecting the tip regions of both fingers carry flow from the deep finger to the tip region of its competitor. This cross-flow is replaced by increasing inflow of aggressive solution into the input of the winner, enhancing further dissolution and growth. On the other hand the cross-flow increases the head at the tip of the losing finger, and consequently decreases inflow of aggressive solution into it, thus inhibiting its further evolution. This mechanism supports further growth of the winner (wormhole) and stops the growth of its competitor. Similar competition happens in the case of several fingers competing. In any case we observe flow from the winning fingers to the loosing ones. The communication between the competitors is always established by cross flow between its tip regions. We will present various scenarios of wormhole formation, which demonstrate details of the competition of fingers arising from either the reactive instability or from the statistical distribution of fracture aperture widths. In conclusion we find that the initiation of wormholes results either from instability or from the statistical distribution of favorable pathways. Once growth of fingers has been initiated the evolution of the wormhole patterns becomes deterministic. (1) Szymczak, P., and A.J.C. Ladd (2011), The initial stages of cave formation: Beyond the one-dimensional paradigm, Earth Planet. Sci. Lett. 301, 424-432 (2) Dreybrodt, W., Gabrovšek, F., Romanov, D.(2005) Processes of Speleogenesis: A Modeling Approach. ZRC Publishing, Karst Research Institute at ZRC SAZU, Ljubljana

Cervical Epidural Hematoma That Induced Sudden Paraparesis After Cervical Spine Massage: Case Report and Literature Review.

PubMed

Ryu, Je Il; Han, Myung Hoon; Kim, Jae Min; Kim, Choong Hyun; Cheong, Jin Hwan

2018-04-01

Most people understand spinal manipulation therapy to be a safe procedure, and in many cases treatment is provided without a diagnosis if there is musculoskeletal pain. Cervical epidural hematoma occurs in extremely rare cases after cervical manipulation therapy. This study reports a case of epidural hematoma that occurred in the anterior spinal cord after cervical massage. A 38-year-old male patient was admitted to the emergency department for sudden weakness in the lower extremity after receiving a cervical spine massage. No fracture was found using cervical radiographs, and there were no particular findings on performing brain computed tomography or diffusion magnetic resonance imaging. However, using cervical magnetic resonance imaging, an acute epidural hematoma was observed in the anterior spinal cord from the C6 and C7 vertebrae to the T1 vertebra, compressing the spinal cord. There were no fractures or ligament injury. No surgical treatment was required as the patient showed spontaneous improvements in muscle strength and was discharged after just 1 week, following observation of the improvement in his symptoms. Although cervical epidural hematoma after cervical manipulation therapy is extremely rare, if suspected, a thorough examination must be performed in order to reduce the chances of serious neurologic sequelae. Copyright © 2018 Elsevier Inc. All rights reserved.

Algodystrophy (CRPS) in minor orthopedic surgery

PubMed Central

Corradini, Costantino; Bosizio, Claudia; Moretti, Antimo

2015-01-01

Summary Algodystrophy or Chronic Regional Pain Syndrome (CRPS) is a painful disorder that develops especially at upper or lower extremities of the limbs after a fracture. This syndrome is probably due to bone microvascular changes with subsequent sympathetic nervous system involvement. The pain that characterizes CRPS is spontaneous, disproportionate to the traumatic event and is associated with hyperalgesia, and a variety of autonomic and trophic disorders. This condition has a variable incidence up to 37% of the cases, increasing along with the severity of the fracture. CRPS has a higher chance of developing in women, in older individuals, in smokers, and in patients with reduced bone strength. Early diagnosis is associated with remission in 80–90% of cases. Since the typical onset of the disease is insidious over 2 weeks after surgery, a diagnostic and therapeutic delay may occur. These are the major causes of a high percentage of chronic and disabling complications leading to impaired functional outcomes. In the acute or subacute phase, infusion of bisphosphonates has proven to be the first-choice of treatment with a high percentage of remissions. Moreover, it has been suggested the utility of vitamin C in prevention of CRPS. Furthermore, in the chronic phase electroanalgesia seems to provide promising results. PMID:27134628

Road traffic accidents in pregnancy in Southwest Nigeria: a 21-year review.

PubMed

Orji, E O; Fadiora, S O; Ogunlola, I O; Badru, O S

2002-09-01

A 21-year (1980-2000) retrospective review of 84 pregnant women involved in road traffic accidents in Southwest Nigeria was conducted. Case notes of these 84 pregnant women treated at the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, were studied. Pregnant women formed 0.3% of all individuals involved in accidents during the study period compared to 7% reported in developed countries. The fetal death rate of 3.6% and maternal death rate of 2.4% in this study were lower than the fetal death rates of 57% and maternal death rate of 8-16% reported in developed countries. There was no obvious injury in 23.8%, while in 76.2% there were serious maternal injuries ranging from limb fractures, pelvic bone fracture, quadriplegia, uterine rupture, abruption placenta, lacerations, etc. Fetal tachycardia was observed in 11.9%. Despite these injuries, the majority (80.9%) achieved spontaneous vaginal deliveries; 16.7% were lost to follow-up, while 2.4% had an emergency caesarean section for reasons unrelated to the accidents. Preventive measures such as proper screening of drivers before issuing driving licences, separation of vehicular and pedestrian traffic, installation and enforcement of the use of seat belts, restrictions of alcohol ingestion while driving, use of a crash helmet by cyclists would drastically reduce the incidence of these accidents.

Engineering Controlled Spalling in (100)-Oriented GaAs for Wafer Reuse

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

Sweet, Cassi A.; McNeely, Joshua E.; Gorman, Brian

Controlled spalling offers a way to cleave thin, single-crystal films or devices from wafers, particularly if the fracture planes in the material are oriented parallel to the wafer surface. Unfortunately, misalignment between the favored fracture planes and the wafer surface preferred for photovoltaic growth in (100)-oriented GaAs produces a highly faceted surface when subject to controlled spalling. This highly faceted cleavage surface is problematic in several ways: (1) it can result in large variations of spall depth due to unstable crack propagation; (2) it may introduce defects into the device zone or underlying substrate; and (3) it consumes many micronsmore » of material outside of the device zone. We present the ways in which we have engineered controlled spalling for (100)-oriented GaAs to minimize these effects. We expand the operational window for controlled spalling to avoid spontaneous spalling, find no evidence of dislocation activity in the spalled film or the parent wafer, and reduce facet height and facet height irregularity. Resolving these issues provides a viable path forward for reducing III-V device cost through the controlled spalling of (100)-oriented GaAs devices and subsequent wafer reuse when these processes are combined with a high-throughput growth method such as Hydride Vapor Phase Epitaxy.« less

Imbibition of hydraulic fracturing fluids into partially saturated shale

NASA Astrophysics Data System (ADS)

Birdsell, Daniel T.; Rajaram, Harihar; Lackey, Greg

2015-08-01

Recent studies suggest that imbibition of hydraulic fracturing fluids into partially saturated shale is an important mechanism that restricts their migration, thus reducing the risk of groundwater contamination. We present computations of imbibition based on an exact semianalytical solution for spontaneous imbibition. These computations lead to quantitative estimates of an imbibition rate parameter (A) with units of LT-1/2 for shale, which is related to porous medium and fluid properties, and the initial water saturation. Our calculations suggest that significant fractions of injected fluid volumes (15-95%) can be imbibed in shale gas systems, whereas imbibition volumes in shale oil systems is much lower (3-27%). We present a nondimensionalization of A, which provides insights into the critical factors controlling imbibition, and facilitates the estimation of A based on readily measured porous medium and fluid properties. For a given set of medium and fluid properties, A varies by less than factors of ˜1.8 (gas nonwetting phase) and ˜3.4 (oil nonwetting phase) over the range of initial water saturations reported for the Marcellus shale (0.05-0.6). However, for higher initial water saturations, A decreases significantly. The intrinsic permeability of the shale and the viscosity of the fluids are the most important properties controlling the imbibition rate.

Wister, CA Downhole and Seismic Data

DOE Data Explorer

Akerley, John

2010-12-18

This submission contains Downhole geophysical logs associated with Wister, CA Wells 12-27 and 85-20. The logs include Spontaneous Potential (SP), HILT Caliper (HCAL), Gamma Ray (GR), Array Induction (AIT), and Neutron Porosity (NPOR) data. Also included are a well log, Injection Test, Pressure Temperature Spinner log, shut in temperature survey, a final well schematic, and files about the well's location and drilling history. This submission also contains data from a three-dimensional (3D) multi-component (3C) seismic reflection survey on the Wister Geothermal prospect area in the northern portion of the Imperial Valley, California. The Wister seismic survey area was 13.2 square miles. (Resistivity image logs (Schlumberger FMI) in 85-20 indicate that maximum horizontal stress (Shmax) is oriented NNE but that open fractures are oriented suboptimally).

Osteomyelitis: A rare complication of pancreatitis and PPP-syndrome.

PubMed

Langenhan, Ronny; Reimers, Niklas; Probst, Axel

2016-03-01

Pancreatic diseases can be accompanied by periarthritis with bone necrosis and panniculitis (PPP-syndrome). It is postulated that this is caused by systemic activity of pancreatic enzymes leading to microcirculatory disturbances and fat necrosis. The morbidity and mortality of the PPP-syndrome is high. Successful treatment of pancreatitis can lead to resolution of accompanying panniculitis and periarthritis without adverse sequelae, but weeks or months after pancreatitis, asymptomatic necrosis of the bone may become symptomatic by fracturing spontaneously. In this report, we also describe osteomyelitis as a severe septic complication of bone necrosis caused by pancreatitis, in one case as acute tissue necrosis and in another case months after pancreatitis spread haematogenously. Copyright © 2015 Société française de rhumatologie. Published by Elsevier SAS. All rights reserved.

Antimicrobial Prophylaxis in Adults

PubMed Central

Enzler, Mark J.; Berbari, Elie; Osmon, Douglas R.

2011-01-01

Antimicrobial prophylaxis is commonly used by clinicians for the prevention of numerous infectious diseases, including herpes simplex infection, rheumatic fever, recurrent cellulitis, meningococcal disease, recurrent uncomplicated urinary tract infections in women, spontaneous bacterial peritonitis in patients with cirrhosis, influenza, infective endocarditis, pertussis, and acute necrotizing pancreatitis, as well as infections associated with open fractures, recent prosthetic joint placement, and bite wounds. Perioperative antimicrobial prophylaxis is recommended for various surgical procedures to prevent surgical site infections. Optimal antimicrobial agents for prophylaxis should be bactericidal, nontoxic, inexpensive, and active against the typical pathogens that can cause surgical site infection postoperatively. To maximize its effectiveness, intravenous perioperative prophylaxis should be administered within 30 to 60 minutes before the surgical incision. Antimicrobial prophylaxis should be of short duration to decrease toxicity and antimicrobial resistance and to reduce cost. PMID:21719623

Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments

USGS Publications Warehouse

Chang, Jefferson C.; Lockner, David A.; Reches, Z.

2012-01-01

After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth’s crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake’s rupture front quickens dynamic weakening by intense wear of the fault zone.

Fan-structure waves in shear ruptures

NASA Astrophysics Data System (ADS)

Tarasov, Boris

2016-04-01

This presentation introduces a recently identified shear rupture mechanism providing a paradoxical feature of hard rocks - the possibility of shear rupture propagation through the highly confined intact rock mass at shear stress levels significantly less than frictional strength. According to the fan-mechanism the shear rupture propagation is associated with consecutive creation of small slabs in the fracture tip which, due to rotation caused by shear displacement of the fracture interfaces, form a fan-structure representing the fracture head. The fan-head combines such unique features as: extremely low shear resistance (below the frictional strength), self-sustaining stress intensification in the rupture tip (providing easy formation of new slabs), and self-unbalancing conditions in the fan-head (making the failure process inevitably spontaneous and violent). An important feature of the fan-mechanism is the fact that for the initial formation of the fan-structure an enhanced local shear stress is required, however, after completion of the fan-structure it can propagate as a dynamic wave through intact rock mass at shear stresses below the frictional strength. Paradoxically low shear strength of pristine rocks provided by the fan-mechanism determines the correspondingly low transient strength of the lithosphere, which favours generation of new earthquake faults in the intact rock mass adjoining pre-existing faults in preference to frictional stick-slip instability along these faults. The new approach reveals an alternative role of pre-existing faults in earthquake activity: they represent local stress concentrates in pristine rock adjoining the fault where special conditions for the fan-mechanism nucleation are created, while further dynamic propagation of the new fault (earthquake) occurs at low field stresses even below the frictional strength.

Anterior augmentation plating of aseptic humeral shaft nonunions after intramedullary nailing.

PubMed

Gessmann, Jan; Königshausen, Matthias; Coulibaly, Marlon Osman; Schildhauer, Thomas Armin; Seybold, Dominik

2016-05-01

Humeral shaft nonunion after intramedullary nailing is a rare but serious complication. Treatment options include implant removal, open plating, exchange nailing and external fixation. The objective of this retrospective study was to determine whether augmentation plating without nail removal is feasible for treating a humeral shaft nonunion. Between 2002 and 2014, 37 patients (mean age 51, range 20-84 years) with aseptic humeral shaft nonunions prior to intramedullary nailing were treated with augmentation plating. The initial fractures had been fixed with retrograde nails (10 cases) or anterograde nails (27 cases). There were 34 atrophic nonunions and 3 hypertrophic nonunions. Nonunion treatment of all patients consisted of local debridement through an anterior approach to the humerus and anterior placement of the augmentation plates. Supplemental bone grafting was performed in all atrophic nonunion cases. All patients were followed until union was radiologically confirmed. Union was achieved in 36 patients (97 %) after a mean of 6 months (range 3-24 months). There was one case of iatrogenic median nerve palsy that showed complete spontaneous recovery 6 weeks postoperatively. One patient sustained a peri-implant stress fracture that was treated successfully by exchanging the augmentation plate to bridge the nonunion and the fracture. No infections or wound healing complications developed. At a mean follow-up of 14 months, all patients showed free shoulder and elbow motion and no restrictions in daily or working life. The results indicate that augmentation plating using an anterior approach is a safe and reliable option for humeral shaft nonunions after failed nailing, and the treatment has no substantial complications. Because the healing rates are similar to the standard technique of nail removal and fixation by compression or locking plates, we consider this technique to be an alternative choice for treatment.

Sounds of Failure: Passive Acoustic Measurements of Excited Vibrational Modes

NASA Astrophysics Data System (ADS)

Brzinski, Theodore A.; Daniels, Karen E.

2018-05-01

Granular materials can fail through spontaneous events like earthquakes or brittle fracture. However, measurements and analytic models which forecast failure in this class of materials, while of both fundamental and practical interest, remain elusive. Materials including numerical packings of spheres, colloidal glasses, and granular materials have been known to develop an excess of low-frequency vibrational modes as the confining pressure is reduced. Here, we report experiments on sheared granular materials in which we monitor the evolving density of excited modes via passive monitoring of acoustic emissions. We observe a broadening of the distribution of excited modes coincident with both bulk and local plasticity, and evolution in the shape of the distribution before and after bulk failure. These results provide a new interpretation of the changing state of the material on its approach to stick-slip failure.

Actinomyces israelii in osteoradionecrosis of the jaws. Histopathologic and immunocytochemical study of five cases

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

Happonen, R.P.; Viander, M.; Pelliniemi, L.

1983-06-01

Five surgically treated patients with osteoradionecrosis of the jaws are presented. The clinical history of the disease varied from 3 to 17 years. In three cases the progression of the disease was enhanced by surgical procedures performed in the irradiated area causing exfoliation of the premaxillary area in one case and spontaneous mandibular fracture in two cases. Actinomyces israelii was demonstrated in tissue sections of all five cases by using FITC-labeled specific antiserum and additionally with peroxidase-antiperoxidase method in one case. Candida was found in histologic sections of three cases. Radiation damage in the oral soft tissues and jawbones makesmore » the atmosphere favorable for anaerobic microorganisms. The present results indicate that the role of A. israelii in the pathogenesis of osteoradionecrosis of the jaws has not been fully appreciated.« less

Sounds of Failure: Passive Acoustic Measurements of Excited Vibrational Modes.

PubMed

Brzinski, Theodore A; Daniels, Karen E

2018-05-25

Granular materials can fail through spontaneous events like earthquakes or brittle fracture. However, measurements and analytic models which forecast failure in this class of materials, while of both fundamental and practical interest, remain elusive. Materials including numerical packings of spheres, colloidal glasses, and granular materials have been known to develop an excess of low-frequency vibrational modes as the confining pressure is reduced. Here, we report experiments on sheared granular materials in which we monitor the evolving density of excited modes via passive monitoring of acoustic emissions. We observe a broadening of the distribution of excited modes coincident with both bulk and local plasticity, and evolution in the shape of the distribution before and after bulk failure. These results provide a new interpretation of the changing state of the material on its approach to stick-slip failure.

Spontaneous telangiectatic osteosarcoma in a rhesus macaque (Macaca mulatta).

PubMed

Goldschmidt, B; Calado, M I Z; Resende, F C; Caldas, R M; Pinto, L W; Lopes, C A A; França, F G O; Meireles, B S; Souza, I V

2017-04-01

Osteosarcoma (OS) is the most common type of bone cancer, especially in young. Telangiectatic osteosarcoma (TO) is a rare variant of OS, and hence, its occurrence, presentation, and prognosis are poorly understood. A 4-year-old female rhesus monkey presenting lameness and swelling was examined for a mass on the right humerus. Radiography revealed fracture and disorganized structure of bone tissue. Histopathological examination revealed malignant neoplasm composed of anaplastic osteoblasts, which invaded the bone marrow and surrounded blood-filled cysts in the epiphysis and diaphysis forming septa. Cytogenetic analysis showed aneuploid cells, supernumerary AgNORs, and a marker fragment. The neoplasm was diagnosed as TO. To our knowledge, the occurrence of TO and its cytogenetic analysis were reported for the first time in non-human primates. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The enduring mark left by Jean-Martin Charcot on rheumatology.

PubMed

Lagier, R

1997-12-01

Although Charcot is remembered above all as an outstanding neurologist, he also left a lasting imprint on the study of rheumatic diseases, primarily in two fields. a) He performed a pathologic-nosographic confrontation based on principles that remain relevant in today's era of imaging techniques. His vision as a pathologist allowed him to establish links between nonspecific lesions, which led him to develop a unified concept of chronic rheumatism. At the same time however, his experience as a clinician gave him a sense of the nosologic distinctions that are widely accepted today. b) He analyzed osteoarticular dystrophies associated with neurologic disorders, most notably tabetic arthropathies with epiphyseal fragmentation and in some instances spontaneous fractures. In addition, a constellation of alterations of the synovial membrane, ligaments, and muscles identified in those analyses foreshadowed today's concept of reflex sympathetic dystrophy syndrome.

Incidence of osteonecrosis of the jaw in women with postmenopausal osteoporosis in the health outcomes and reduced incidence with zoledronic acid once yearly pivotal fracture trial.

PubMed

Grbic, John T; Landesberg, Regina; Lin, Shou-Qing; Mesenbrink, Peter; Reid, Ian R; Leung, Ping-Chung; Casas, Noemi; Recknor, Christopher P; Hua, Ye; Delmas, Pierre D; Eriksen, Erik F

2008-01-01

The authors determined incidence of osteonecrosis of the jaw (ONJ) in a large, prospective three-year clinical trial of zoledronic acid in women with postmenopausal osteoporosis (PMO). A total of 7,714 women with PMO received intravenous zoledronic acid 5 mg or a placebo. No spontaneous reports of ONJ were received. An independent, blinded adjudication committee searched the trial's adverse event database by using 60 terms. On an ongoing basis, the committee reviewed the identified events, and it defined ONJ as exposed bone in the maxillofacial area with delayed healing for more than six weeks despite appropriate care. One participant who received a placebo and one participant who received zoledronic acid experienced delayed healing associated with infection. Both conditions resolved after antibiotic therapy, débridement or both. The occurrence of ONJ is rare in a PMO population, and delayed healing of lesions can occur with and without bisphosphonate use over three years. The low incidence of ONJ must be assessed in the context of the clinical benefit of zoledronic acid therapy in reducing hip, vertebral and nonvertebral fractures in this at-risk population. There is no evidence to suggest that healthy patients with osteoporosis who are receiving bisphosphonates require any special treatment beyond routine dental care or to support altering standard treatment practices.

Assessment and clinical management of bone disease in adults with eating disorders: a review.

PubMed

Drabkin, Anne; Rothman, Micol S; Wassenaar, Elizabeth; Mascolo, Margherita; Mehler, Philip S

2017-01-01

To review current medical literature regarding the causes and clinical management options for low bone mineral density (BMD) in adult patients with eating disorders. Low bone mineral density is a common complication of eating disorders with potentially lifelong debilitating consequences. Definitive, rigorous guidelines for screening, prevention and management are lacking. This article intends to provide a review of the literature to date and current options for prevention and treatment. Current, peer-reviewed literature was reviewed, interpreted and summarized. Any patient with lower than average BMD should weight restore and in premenopausal females, spontaneous menses should resume. Adequate vitamin D and calcium supplementation is important. Weight-bearing exercise should be avoided unless cautiously monitored by a treatment team in the setting of weight restoration. If a patient has a Z-score less than expected for age with a high fracture risk or likelihood of ongoing BMD loss, physiologic transdermal estrogen plus oral progesterone, bisphosphonates (alendronate or risedronate) or teriparatide could be considered. Other agents, such as denosumab and testosterone in men, have not been tested in eating-disordered populations and should only be trialed on an empiric basis if there is a high clinical concern for fractures or worsening bone mineral density. A rigorous peer-based approach to establish guidelines for evaluation and management of low bone mineral density is needed in this neglected subspecialty of eating disorders.

Z-plasty of the flexor hallucis longus tendon at tarsal tunnel for checkrein deformity.

PubMed

Lee, Jae Hoon; Kim, Young Jun; Baek, Jong Hun; Kim, Dong Hee

2016-12-01

To review the outcome of Z-plasty of the flexor hallucis longus (FHL) tendon at the tarsal tunnel for checkrein deformity in 8 patients. Records of 6 males and 2 females aged 14 to 67 (mean, 39.5) years who underwent Z-plasty (lengthening) of the FHL tendon at the tarsal tunnel for checkrein deformity in the first and second toes by a single surgeon were reviewed. All patients had undergone 3 months of conservative treatment. The mean time from injury to surgical treatment was 8.4 (range, 5-12) months. All patients had associated injuries including distal tibiofibular fracture (n=6), distal fibular fracture (n=1), and crush injury aroundthe ankle (n=1); they were treated with intramedullary nailing (n=6), long leg splinting (n=1), and short leg splinting (n=1). After a mean follow-up of 3.4 (range, 1-7) years, the FHL tendon was lengthened by a mean of 1.7 (range, 1.6-1.8) cm, and the mean American Orthopedic Foot and Ankle Society hallux score increased from 59 (range, 52-67) to 89 (range, 80-90). No patient had recurrence, nerve injury, or tarsal tunnel syndrome, although one patient had sensory disturbance of the posterior tibial nerve in the forefoot, which resolved spontaneously at week 2. Z-plasty of the FHL tendon at the tarsal tunnel is a viable option for correction of checkrein deformity.

[Management of blunt duodenal and pancreatic injuries in children (about a series of 8 cases)].

PubMed

Ben Hassine, Lilia; Boughanmi, Nizar; Douira, Wiem; Mormeche, Jihene; Louati, Hela; Hamzaoui, Mourad; Chaouachi, Beji; Bellagha, Ibtissem

2010-08-01

The aim of this retrospective study is to report eight cases of blunt duodeno-pancreatic trauma in infants, emphasizing on the role of imaging in acute assessment of the lesions and in further management. We reported eight cases of duodeno-pancreatic injuries between 2006 and 2008, 5 boys and 3 girls with an age ranging from 3 to 12 years (median age: 7 years). Trauma circumstances were: car accident (n=2), domestic injury (n=5) and bicycle's fall injury (n=1). All patients underwent abdominal ultrasonography and CT scan in the initial evaluation and during the follow-up. Imaging showed the following pancreatic lesions: 3 corporeal fractures, 2 caudal fractures and one between the corporeal and the caudal portions. Four pancreatic haematomas were found. The associated lesions were duodenal, splenic, hepatic and renal. Two isolated duodenal haematomas were found. Two patients improved spontaneously, the six others developed complications: 4 acute pancreatitis, two infections, 3 pseudocysts and one retroperitoneal collection. Management was chirurgical in one case, medical in two cases, endoscopic in 2 cases and three percutaneaous drainages were performed. Blunt duodeno-pancreatic injuries in children have to be evaluated by an early imaging modality, in order to perform acute assessment of the lesions. Primary conservative treatment is advocated while clinic, biologic and imaging follow-up is required to detect complications, which management can be endoscopic, percutaneous or surgical.

Numerical Modelling by FLAC on Coal Fires in North China

NASA Astrophysics Data System (ADS)

Gusat, D.; Drebenstedt, C.

2009-04-01

Coal fires occur in many countries all over the world (e.g. Australia, China, India, Indonesia, USA and Russia) in underground and on surface. In China the most coal fires occur especially in the North. Economical and environmental damages are the negative effects of the coal fires: coal fires induce open fractures and fissures within the seam and neighbouring rocks. So that these are the predominant pathways for oxygen flow and exhaust gases from a coal fire. All over northern China there are a large number of coal fires, which cause and estimated yearly coal loss of between 100 and 200 million tons ([1], [2], [3]). Spontaneous combustion is a very complicated process and is influenced by number of factors. The process is an exothermic reaction in which the heat generated is dissipated by conduction to the surrounding environment, by radiation, by convection to the ventilation flow, and in some cases by evaporation of moisture from the coal [4]. The coal fires are very serious in China, and the dangerous extent of spontaneous combustion is bad which occupies about 72.9% in mining coal seams. During coal mining in China, the coal fires of spontaneous combustion are quite severity. The dangerous of coal spontaneous combustion has been in 56% of state major coalmines [5]. The 2D and 3D-simulation models describing coal fire damages are strong tools to predict fractures and fissures, to estimate the risk of coal fire propagation into neighbouring seams, to test and evaluate coal fire fighting and prevention methods. The numerical simulations of the rock mechanical model were made with the software for geomechanical and geotechnical calculations, the programs FLAC and FLAC3D [6]. To fight again the coal fires, exist several fire fighting techniques. Water, slurries or liquefied nitrogen can be injected to cool down the coal or cut of air supply with the backfill and thereby extinct the fire. Air supply also can be cut of by covering the coal by soil or sealing of the coal mine with the backfill. A smaller fires can also be handled by taking out burning coal by bulldozing techniques described above are applicable to small fires, but they do not work well in extinction of large coal fires. References [1] http://www.coalfire.caf.dlr.de [2] Schalke, H.J.W.G.; Rosema, A.; Van Genderen, J.L. (1993): Environmental monitoring of coal fires in North China. Project Identification Mission Report. Report Remote Sensing Programme Board, Derft, the Netherlands. [3] Zhang, X.; Kroonenberg, S. B.; De Boer, C. B. (2004): Dating of coal fires in Xinjiang, north-west China. Terra Nova. Band 16, No 2, S. 68-74. DOI: 10.1111/j.1365-3121.2004.00532.x [4] Deng Jun, Hou Shuang, Li Huirong, e.t.c (2006): Oxidation Mechanism at Initial Stage of a Simulated Coal Molecule with -CH2O-[J]. Journal of Changchun University of Science and Technology, 29(2), P. 84-87. [5] Deng, Jun (2008): Presentation. Chinese Researches and Practical Experiences on Controlling Underground Coal Fires. The 2nd Australia-China Symposium on Science, Technology and Education. 15-18 October 2008, Courtyard Marriott, Surfers Paradise Beach, Gold Coast, Queensland, Australia. [6] Itasca (2003): FLAC, Fast Lagrangian Analysis of Continua. Itasca Consultants Group, Inc., Minneapolis.

Pathological Calcification and Ossification in Relation to Leriche and Policard's Theory.

PubMed

Jones, W; Roberts, R E

1933-05-01

(1) Pathology of calcification and ossification.-The Leriche-Policard theories. Hyperaemia of bone causes decalcification. Reduced blood supply causes sclerosis. Diminution of vascularity of fibrous tissue causes calcification. Excess of calcium, adequate blood supply and fibroblasts give rise to bone anywhere. Subperiosteal ossification. "Myositis ossificans."(2) Radiological significance of density of bone shadows.-Decalcification of disuse, of infections, of neoplasms. Traumatic and infective scquestra. Evidence that a fragment of bone is avascular.(3) Hyperaemic decalcification of bone.-Delayed and non-union of fractures. Kummel's disease. Spontaneous hyperaemic dislocation of the atlas. Hyperaemic decalcification and nephrolithiasis.(4) Anaemic sclerosis of bone.-Syphilitic bone disease. Malignant bone disease. Fragility of sclerosed bone-Paget's, Kienboch's, Kohler's and Panner's, Albers-Schönberg's diseases.(5) Pathological calcification.-Calcification of supraspinatus tendon. Calcification of tumours-angioma, haematoma, and thrombosed vessels, lipoma, cysts, etc. Calcification of semilunar cartilages and intervertebral discs.(6) Pathological ossification.-Ossification of tendons. Ossification of semilunar cartilages.

Tantalum—A bioactive metal for implants

NASA Astrophysics Data System (ADS)

Balla, Vamsi Krishna; Bose, Susmita; Davies, Neal M.; Bandyopadhyay, Amit

2010-07-01

Metallic biomaterials currently in use for load-bearing orthopedic applications are mostly bioinert and therefore lack sufficient osseointegration. Although bioactive ceramics such as hydroxyapatite (HA) can spontaneously bond to living bone tissue, low fracture toughness of HA limits their use as a bone substitute for load-bearing applications. Surface modification techniques such as HA coating on metals are current options to improve osseointegration in load-bearing metal implants. Over the last few decades researchers have attempted to find a bioactive metal with high mechanical strength and excellent fatigue resistance that can bond chemically with surrounding bone for orthopedic applications. Recent in vitro, in vivo, and clinical studies demonstrated that tantalum is a promising metal that is bioactive. However, tantalum applications in biomedical devices have been limited by processing challenges rather than biological performances. In this article, we provide an overview of processing aspects and biological properties of tantalum for load-bearing orthopedic applications.

Subdural hematoma caused by intracranial hypotension after syringosubarachnoid shunting--case report.

PubMed

Yamazaki, Tomosato; Yanaka, Kiyoyuki; Uemura, Kazuya; Tsukada, Atsuro

2004-09-01

A 32-year-old man developed an extremely rare subdural hematoma after syringosubarachnoid shunting for syringomyelia. He presented with a 4-year history of neck pain and spastic paraparesis resulting from T-7 and T-8 vertebral body fracture suffered in a traffic accident at age 22 years. Magnetic resonance imaging revealed syringomyelia between the craniocervical junction and the T-10 level. The symptoms were slowly progressive, and a syringosubarachnoid shunting was performed. His spasticity improved after surgery, but he developed orthostatic headache 7 days after surgery. Magnetic resonance imaging of the brain demonstrated a thin subdural hematoma over the right cerebral convexity. The subdural hematoma resolved spontaneously within a week with conservative treatment. Vigorous cerebrospinal fluid outflow observed during surgery presumably lowered the pressure in the syrinx cavity, leading to significant but transient intracranial hypotension and consequently the formation of subdural hematoma.

Electronic cigarette explosions involving the oral cavity.

PubMed

Harrison, Rebecca; Hicklin, David

2016-11-01

The use of electronic cigarettes (e-cigarettes) is a rapidly growing trend throughout the United States. E-cigarettes have been linked to the risk of causing explosion and fire. Data are limited on the associated health hazards of e-cigarette use, particularly long-term effects, and available information often presents conflicting conclusions. In addition, an e-cigarette explosion and fire can pose a unique treatment challenge to the dental care provider because the oral cavity may be affected heavily. In this particular case, the patient's injuries included intraoral burns, luxation injuries, and alveolar fractures. This case report aims to help clinicians gain an increased knowledge about e-cigarette design, use, and risks; discuss the risk of spontaneous failure and explosion of e-cigarettes with patients; and understand the treatment challenges posed by an e-cigarette explosion. Copyright © 2016 American Dental Association. Published by Elsevier Inc. All rights reserved.

A Novel Minimally Invasive Technique for Treatment of Unicameral Bone Cysts

PubMed Central

Zaghloul, Ahmed; Haddad, Behrooz; Khan, Wasim; Grimes, Lisa; Tucker, Keith

2015-01-01

Management of unicameral bone cysts (UBC) remain controversial. These cysts seldom heal spontaneously or even after pathological fracture. Sometimes these cysts can be very large and incredibly troublesome to the patient. Various treatments exist with variable success rates. We present our experience of treating these lesions by continuous drainage. Over a seven year period, six patients with unicameral bone cysts were treated by inserting a modified drain into the wall of the cyst. The aim of surgery was to place the drain in a dependent area of the cyst, through the cortex allowing for continuous drainage. This was achieved through a small incision under radiographic control. A cement restrictor (usually used for femoral canal plugging during total hip replacements) was modified and inserted to prevent closure of the drain site. A redivac drain was passed through the plug into the cyst. The drain was left in place for a week to establish an epithelialized pathway which hopefully would remain patent, into the subcutaneous tissues, after the drain had been removed. There were four males and two females in the group and the age range was 6 -12 years. Four of the lesions were in the upper humerus, one in the proximal femur and the other one in the proximal tibia. Healing was rated according to the modified Neer classification. Grade 1 (healed) and Grade 2 (healed with defect) was defined as excellent outcome. Persistent /Recurrent cysts (Grade 3 and 4) were noted as unsatisfactory. Five cases were completely healed. Only one had a further fracture and there were no recurrent fractures. All the patients reported complete comfort and they all were able to re-engage in recreational activities without restriction. We think that reducing the intra-medullary pressure in these lesions will lead to healing. We report a safe and minimally invasive technique for the management of UBC. PMID:26587064

A Novel Minimally Invasive Technique for Treatment of Unicameral Bone Cysts.

PubMed

Zaghloul, Ahmed; Haddad, Behrooz; Khan, Wasim; Grimes, Lisa; Tucker, Keith

2015-01-01

Management of unicameral bone cysts (UBC) remain controversial. These cysts seldom heal spontaneously or even after pathological fracture. Sometimes these cysts can be very large and incredibly troublesome to the patient. Various treatments exist with variable success rates. We present our experience of treating these lesions by continuous drainage. Over a seven year period, six patients with unicameral bone cysts were treated by inserting a modified drain into the wall of the cyst. The aim of surgery was to place the drain in a dependent area of the cyst, through the cortex allowing for continuous drainage. This was achieved through a small incision under radiographic control. A cement restrictor (usually used for femoral canal plugging during total hip replacements) was modified and inserted to prevent closure of the drain site. A redivac drain was passed through the plug into the cyst. The drain was left in place for a week to establish an epithelialized pathway which hopefully would remain patent, into the subcutaneous tissues, after the drain had been removed. There were four males and two females in the group and the age range was 6 -12 years. Four of the lesions were in the upper humerus, one in the proximal femur and the other one in the proximal tibia. Healing was rated according to the modified Neer classification. Grade 1 (healed) and Grade 2 (healed with defect) was defined as excellent outcome. Persistent /Recurrent cysts (Grade 3 and 4) were noted as unsatisfactory. Five cases were completely healed. Only one had a further fracture and there were no recurrent fractures. All the patients reported complete comfort and they all were able to re-engage in recreational activities without restriction. We think that reducing the intra-medullary pressure in these lesions will lead to healing. We report a safe and minimally invasive technique for the management of UBC.

Self-assembly of graphene ribbons by spontaneous self-tearing and peeling from a substrate

NASA Astrophysics Data System (ADS)

Annett, James; Cross, Graham L. W.

2016-07-01

Graphene and related two-dimensional materials have shown unusual and exceptional mechanical properties, with similarities to origami-like paper folding and kirigami-like cutting demonstrated. For paper analogues, a critical difference between macroscopic sheets and a two-dimensional solid is the molecular scale of the thin dimension of the latter, allowing the thermal activation of considerable out-of-plane motion. So far thermal activity has been shown to produce local wrinkles in a free graphene sheet that help in theoretically understanding its stability, for example, and give rise to unexpected long-range bending stiffness. Here we show that thermal activation can have a more marked effect on the behaviour of two-dimensional solids, leading to spontaneous and self-driven sliding, tearing and peeling from a substrate on scales approaching the macroscopic. We demonstrate that scalable nanoimprint-style contact techniques can nucleate and direct the parallel self-assembly of graphene ribbons of controlled shape in ambient conditions. We interpret our observations through a simple fracture-mechanics model that shows how thermodynamic forces drive the formation of the graphene-graphene interface in lieu of substrate contact with sufficient strength to peel and tear multilayer graphene sheets. Our results show how weak physical surface forces can be harnessed and focused by simple folded configurations of graphene to tear the strongest covalent bond. This effect may hold promise for the patterning and mechanical actuating of devices based on two-dimensional materials.

Spiral interface: A reinforcing mechanism for laminated composite materials learned from nature

NASA Astrophysics Data System (ADS)

Gao, Yang; Guo, Zhenbin; Song, Zhaoqiang; Yao, Haimin

2017-12-01

Helical structures are ubiquitous in nature at length scales of a wide range. In this paper, we studied a helical architecture called microscopic screw dislocation (μ-SD), which is prevalently present in biological laminated composites such as shells of mollusks P. placenta and nacre of abalone. Mechanical characterization indicated that μ-SDs can greatly enhance resistance to scratching. To shed light on the underlying reinforcing mechanisms, we systematically investigated the mechanical behaviors of μ-SD using theoretical modeling in combination with finite element simulation. Our analysis on an individual μ-SD showed that the failure of a μ-SD under tension involves the delamination of the prolonged spiral interface, giving rise to much higher toughness compared to those of the planar counterpart. The corporation of multiple μ-SDs was further investigated by analyzing the effect of μ-SD density on the mechanical reinforcement. It was found that higher areal density of μ-SD would lead to more improvement in toughness. However, the operation of such reinforcing mechanism of μ-SD requires proclivity of cracking along the spiral interface, which is not spontaneous but conditional. Fracture mechanics-based modeling indicated that the proclivity of crack propagation along the spiral interface can be ensured if the fracture toughness of the interface is less than 60% of that of the lamina material. These findings not only uncover the reinforcing mechanisms of μ-SDs in biological materials but imply a great promise of applying μ-SDs in reinforcing synthetic laminated composites.

Sliced Costochondral Chip Grafts in Posttraumatic Enophthalmos Correction.

PubMed

Kim, Tae-Hoon; Park, Ie-Hyon; Hong, Sa-Hyeok; Eun, Seok-Chan

2017-03-01

Posttraumatic enophthalmos is a relatively common problem following orbitozygomatic fractures. However, inadequate long-term results are frequently observed due to the difficulty of performing intraoperative fine adjustments to soft-tissue volume and orbital size and gradual absorption of some grafted materials. Here, the authors describe an efficient method of enophthalmos correction using sliced costochondral bone and cartilage combination grafts. From 2005 to 2011, the authors corrected enophthalmos in 12 patients using sliced costochondral grafts. The mean follow-up period was 13 months. For costochondral graft harvest, an approximately 5-cm skin incision was made directly above the seventh costal cartilage, the perichondrium was peeled back, and a small piece of rib bone and costal cartilage was harvested from the anterior part of the seventh rib bone and cartilage and cut into 2-mm-thick slices. A subciliary and/or transcaruncular incision was made in the affected side eyelid to expose the operating field, subperiosteal dissection was performed in the orbit and orbital floor. The cartilage chips were gradually grafted onto the dissected areas from the posterior orbit. Aesthetically satisfactory results were obtained in all patients. No complications in the donor area were observed. Furthermore, no patients experienced a recurrence or deterioration of diplopia over the follow-up period. One patient experienced temporary high intraocular pressure, which spontaneously resolved with medication and eye drops. The costochondral graft is adequate for the reconstruction of the fracture, easy to obtain, easily adaptable to the orbital walls, and has minimal morbidity at the donor site.

Use of geophysical methods to characterize groundwater in karstic rocks near Puerto Morelos, Yucatan Peninsula, Mexico

NASA Astrophysics Data System (ADS)

cerda Garcia, C. G.; Carpenter, P. J.; Leal-Bautista, R. M.

2017-12-01

Geophysical surveys were used to determine the depth of the freshwater/saltwater interface and groundwater preferential flow pathways along the Ruta de los Cenotes, near Puerto Morelos (northeast part of the Yucatán peninsula). The Yucatán Peninsula is a limestone platform that allows quick recharge of the aquifer, the main supply of water for this region. The water in the aquifer is divided into freshwater and saltwater zones. A Schlumberger resistivity sounding along the road near one cenote suggests the water table is 5 meters deep and the freshwater/saltwater interface is 38 meters deep. A time-domain electromagnetic (TEM) sounding suggests the freshwater/saltwater interface is 45 meters deep. The depth of the interface determines the volume of fresh water available. Preferential flow pathways in the vadose and saturated zones are karst conduits where groundwater percolates downward in the vadose zone. These were identified using resistivity profiling and spontaneous self-potential (SP) geophysical methods. Interpretation of SP profile Line SP1, located 3 m south of the cenote, suggests two fractures, which appear to extend south as far as SP profile Line SP2, 15 m south of the cenote; both lines are parallel to each other. SP anomalies suggest water flow along these fractures. The use of noninvasive geophysical methods, specifically SP, resistivity and TEM are useful for exploring the karst system in the Yucatán peninsula.

Large pneumothorax in blunt chest trauma: Is a chest drain always necessary in stable patients? A case report.

PubMed

Idris, Baig M; Hefny, Ashraf F

2016-01-01

Pneumothorax is the most common potentially life-threatening blunt chest injury. The management of pneumothorax depends upon the etiology, its size and hemodynamic stability of the patient. Most clinicians agree that chest drainage is essential for the management of traumatic large pneumothorax. Herein, we present a case of large pneumothorax in blunt chest trauma patient that resolved spontaneously without a chest drain. A 63- year- old man presented to the Emergency Department complaining of left lateral chest pain due to a fall on his chest at home. On examination, he was hemodynamically stable. An urgent chest X-ray showed evidence of left sided pneumothorax. CT scan of the chest showed pneumothorax of more than 30% of the left hemithorax (around 600ml of air) with multiple left ribs fracture. Patient refused tube thoracostomy and was admitted to surgical department for close observation. The patient was managed conservatively without chest tube insertion. A repeat CT scan of the chest has shown complete resolution of the pneumothorax. The clinical spectrum of pneumothorax varies from asymptomatic to life threatening tension pneumothorax. In stable patients, conservative management can be safe and effective for small pneumothorax. To the best of our knowledge, this is the second reported case in the English literature with large pneumothorax which resolved spontaneously without chest drain. Blunt traumatic large pneumothorax in a clinically stable patient can be managed conservatively. Current recommendations for tube placement may need to be reevaluated. This may reduce morbidity associated with chest tube thoracostomy. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

[Interpretation of elevated serum troponin levels in end stage renal disease - case 2/2010].

PubMed

Artunc, Ferruh; Haap, Michael; Heyne, Nils; Weyrich, Peter; Wolf, Sabine

2010-02-01

We report on a female patient with rheumatoid arthritis and end-stage renal-disease following AA-amyloidosis who presented with chest pain to the emergency department. ECG showed no signs of ischemia, echocardiography revealed a concentric left ventricular hypertrophy with increased texture. Serum concentration of troponin I was mildly elevated whereas creatine kinase (CK)/ CK-MB were normal. The chief complaints resolved spontaneously and there was no change in the serum troponin-I and CK/CK-MB concentrations. Coronary heart disease was ruled out by angiography and cardiac involvement of the underlying AA-amyloidosis was diagnosed. After one month, the patient suffered from a syncope complicated by a pelvic ring fracture with hemorrhagic shock and declined chronic dialysis treatment. Patients with end-stage renal disease may exhibit a persisting elevation of serum troponin concentration reflecting the high burden of cardiovascular disease. Myocardial infarction can be distinguished by the lack of increase in serial tests. Copyright Georg Thieme Verlag KG Stuttgart . New York.

‘Miracle baby’: an outcome of multidisciplinary approach to neurotrauma in pregnancy

PubMed Central

Neville, Grace; Kaliaperumal, Chandrasekaran; Kaar, George

2012-01-01

Traumatic brain injury (TBI) warranting neurosurgical intervention in the pregnant population is a rarity. We describe a case of a 27-year-old woman who at 13 weeks of gestation presented with multiple traumas having been involved in a near fatal road traffic accident. Glasgow Coma Scale was 6/15. CT brain showed extensive haemorrhagic contusions, diffuse brain swelling and multiple skull and facial fractures. Decompressive craniectomy was performed to control her intracranial pressure during her management in the intensive care. A viable intrauterine pregnancy was confirmed and progressed as maternal stabilisation and rehabilitation continued. At 35+3 weeks a 2770 g male child was delivered via emergency caesarean section after spontaneous onset of labour. The child had no detectable abnormalities and is clinically well. Eight months post-TBI the patient continues to make gradual improvements but is left with severe cognitive impairment and currently undergoing rehabilitation. A multidisciplinary approach was adopted in the management of this patient. PMID:22805738

The cell biology and role of resorptive cells in diseases: A review.

PubMed

Babaji, Prashant; Devanna, Raghu; Jagtap, Kiran; Chaurasia, Vishwajit Rampratap; Jerry, Jeethu John; Choudhury, Basanta Kumar; Duhan, Dinesh

2017-01-01

Resorptive cells are responsible for the resorption of mineralized matrix of hard tissues. Bone-resorbing cells are called osteoclasts; however, they can resorb mineralized dental tissues or calcified cartilage and then they are called odontoclasts and chondroclasts, respectively. Resorptive cells form when mononuclear precursors derived from a monocyte-macrophage cell lineage are attracted to certain mineralized surfaces and subsequently fuse and adhere onto them for exerting their resorbing activity. These cells are responsible for degradation of calcified extracellular matrix composed of organic molecules and hydroxyapatite. The activity of these cells can be observed in both physiological and pathological processes throughout life and their activity is mainly required in bone turnover and growth, spontaneous and induced (orthodontic) tooth movement, tooth eruption, and bone fracture healing, as well as in pathological conditions such as osteoporosis, osteoarthritis, and bone metastasis. In addition, they are responsible for daily control of calcium homeostasis. Clastic cells also resorb the primary teeth for shedding before the permanent teeth erupt into the oral cavity.

Modelling tidewater glacier calving: from detailed process models to simple calving laws

NASA Astrophysics Data System (ADS)

Benn, Doug; Åström, Jan; Zwinger, Thomas; Todd, Joe; Nick, Faezeh

2017-04-01

The simple calving laws currently used in ice sheet models do not adequately reflect the complexity and diversity of calving processes. To be effective, calving laws must be grounded in a sound understanding of how calving actually works. We have developed a new approach to formulating calving laws, using a) the Helsinki Discrete Element Model (HiDEM) to explicitly model fracture and calving processes, and b) the full-Stokes continuum model Elmer/Ice to identify critical stress states associated with HiDEM calving events. A range of observed calving processes emerges spontaneously from HiDEM in response to variations in ice-front buoyancy and the size of subaqueous undercuts, and we show that HiDEM calving events are associated with characteristic stress patterns simulated in Elmer/Ice. Our results open the way to developing calving laws that properly reflect the diversity of calving processes, and provide a framework for a unified theory of the calving process continuum.

Nutritional secondary hyperparathyroidism in the animal kingdom: report of two cases.

PubMed

Krook, Lennart; Whalen, Joseph P

2010-01-01

This report describes two cases of marked bone loss (osteopenia) occurring in a 9-week-old German shepherd puppy and in a 6-month-old tiger. In both cases the animals were fed a diet which was exclusively boneless meat. The diets in both cases contained approximately 40 mg of calcium and 1000 mg of phosphorus per pound resulting in both calcium deficiency and phosphorus excess, resulting in a phosphorus-to-calcium ratio of 25:1, well beyond the amounts known to cause marked loss of bone experimentally. This has been termed nutritional secondary hyperparathyroidism (NSH). Both animals presented with severe bone pain, difficulty in ambulation, and difficulty in chewing food. Radiographs showed marked osteopenia and spontaneous fractures. Both responded clinically and radiographically to calcium supplementation and a diet with an appropriate phosphorus-to-calcium ratio. The importance of calcium and phosphorus in the human diet is briefly discussed. Copyright © 2010 Elsevier Inc. All rights reserved.

Lumbar vertebral hemangioma mimicking lateral spinal canal stenosis: case report and review of literature.

PubMed

Syrimpeis, Vasileios; Vitsas, Vasileios; Korovessis, Panagiotis

2014-03-01

Context Hemangiomas are the commonest benign tumors of the spine. Most occur in the thoracolumbar spine and the majority are asymptomatic. Rarely, hemangiomas cause symptoms through epidural expansion of the involved vertebra, resulting in spinal canal stenosis, spontaneous epidural hemorrhage, and pathological burst fracture. Findings We report a rare case of a 73-year-old woman, who had been treated for two months for degenerative neurogenic claudication. On admission, magnetic resonance imaging and computed tomographic scans revealed a hemangioma of the third lumbar vertebra protruding to the epidural space producing lateral spinal stenosis and ipsilateral nerve root compression. The patient underwent successful right hemilaminectomy for decompression of the nerve root, balloon kyphoplasty with poly-methyl methacrylate (PMMA) and pedicle screw segmental stabilization. Postoperative course was uneventful. Conclusion In the elderly, this rare presentation of spinal stenosis due to hemangiomas may be encountered. Decompression and vertebral augmentation by means balloon kyphoplasty with PMMA plus segmental pedicle screw fixation is recommended.

Lumbar vertebral hemangioma mimicking lateral spinal canal stenosis: Case report and review of literature

PubMed Central

Syrimpeis, Vasileios; Vitsas, Vasileios; Korovessis, Panagiotis

2014-01-01

Context Hemangiomas are the commonest benign tumors of the spine. Most occur in the thoracolumbar spine and the majority are asymptomatic. Rarely, hemangiomas cause symptoms through epidural expansion of the involved vertebra, resulting in spinal canal stenosis, spontaneous epidural hemorrhage, and pathological burst fracture. Findings We report a rare case of a 73-year-old woman, who had been treated for two months for degenerative neurogenic claudication. On admission, magnetic resonance imaging and computed tomographic scans revealed a hemangioma of the third lumbar vertebra protruding to the epidural space producing lateral spinal stenosis and ipsilateral nerve root compression. The patient underwent successful right hemilaminectomy for decompression of the nerve root, balloon kyphoplasty with poly-methyl methacrylate (PMMA) and pedicle screw segmental stabilization. Postoperative course was uneventful. Conclusion In the elderly, this rare presentation of spinal stenosis due to hemangiomas may be encountered. Decompression and vertebral augmentation by means balloon kyphoplasty with PMMA plus segmental pedicle screw fixation is recommended. PMID:24090267

An animal model in sheep for biocompatibility testing of biomaterials in cancellous bones

PubMed Central

Nuss, Katja MR; Auer, Joerg A; Boos, Alois; Rechenberg, Brigitte von

2006-01-01

Background The past years have seen the development of many synthetic bone replacements. To test their biocompatibility and ability for osseointegration, osseoinduction and -conduction requires their placement within bone preferably in an animal experiment of a higher species. Methods A suitable experimental animal model in sheep with drill holes of 8 mm diameter and 13 mm depth within the proximal and distal humerus and femur for testing biocompatibility issues is introduced. Results This present sheep model allows the placing of up to 8 different test materials within one animal and because of the standardization of the bone defect, routine evaluation by means of histomorphometry is easily conducted. This method was used successfully in 66 White Alpine Sheep. When the drill holes were correctly placed no complications such as spontaneous fractures were encountered. Conclusion This experimental animal model serves an excellent basis for testing the biocompatibility of novel biomaterials to be used as bone replacement or new bone formation enhancing materials. PMID:16911787

An animal model in sheep for biocompatibility testing of biomaterials in cancellous bones.

PubMed

Nuss, Katja M R; Auer, Joerg A; Boos, Alois; von Rechenberg, Brigitte

2006-08-15

The past years have seen the development of many synthetic bone replacements. To test their biocompatibility and ability for osseointegration, osseoinduction and -conduction requires their placement within bone preferably in an animal experiment of a higher species. A suitable experimental animal model in sheep with drill holes of 8 mm diameter and 13 mm depth within the proximal and distal humerus and femur for testing biocompatibility issues is introduced. This present sheep model allows the placing of up to 8 different test materials within one animal and because of the standardization of the bone defect, routine evaluation by means of histomorphometry is easily conducted. This method was used successfully in 66 White Alpine Sheep. When the drill holes were correctly placed no complications such as spontaneous fractures were encountered. This experimental animal model serves an excellent basis for testing the biocompatibility of novel biomaterials to be used as bone replacement or new bone formation enhancing materials.

Toughening mystery of natural rubber deciphered by double network incorporating hierarchical structures

PubMed Central

Zhou, Weiming; Li, Xiangyang; Lu, Jie; Huang, Ningdong; Chen, Liang; Qi, Zeming; Li, Liangbin; Liang, Haiyi

2014-01-01

As an indispensible material for modern society, natural rubber possesses peerless mechanical properties such as strength and toughness over its artificial analogues, which remains a mystery. Intensive experimental and theoretical investigations have revealed the self-enhancement of natural rubber due to strain-induced crystallization. However a rigorous model on the self-enhancement, elucidating natural rubber's extraordinary mechanical properties, is obscured by deficient understanding of the local hierarchical structure under strain. With spatially resolved synchrotron radiation micro-beam scanning X-ray diffraction we discover weak oscillation in distributions of strain-induced crystallinity around crack tip for stretched natural rubber film, demonstrating a soft-hard double network structure. The fracture energy enhancement factor obtained by utilizing the double network model indicates an enhancement of toughness by 3 orders. It's proposed that upon stretching spontaneously developed double network structures integrating hierarchy at multi length-scale in natural rubber play an essential role in its remarkable mechanical performance. PMID:25511479

Functional analysis of tight junction organization.

PubMed

DiBona, D R

1985-01-01

The functional basis of tight junction design has been examined from the point of view that this rate-limiting barrier to paracellular transport is a multicompartment system. Review of the osmotic sensitivity of these structures points to the need for this sort of analysis for meaningful correlation of structure and function under a range of conditions. A similar conclusion is drawn with respect to results from voltage-clamping protocols where reversal of spontaneous transmural potential difference elicits parallel changes in both structure and function in much the same way as does reversal of naturally occurring osmotic gradients. In each case, it becomes necessary to regard the junction as a functionally polarized structure to account for observations of its rectifying properties. Lastly, the details of experimentally-induced junction deformation are examined in light of current theories of its organization; arguments are presented in favor of the view that the primary components of intramembranous organization (as viewed with freeze-fracture techniques) are lipidic rather than proteinaceous.

Eyelid Edema: A Rare Cause of a Common Sign

PubMed Central

Almeida, Cristina; Freitas, Cristina; Sales-Sanz, Marco; Ribeiro, Sara

2017-01-01

We report a 48-year-old female patient who presented to the emergency room with right eyelid edema, with 3 days of evolution. She had suffered minor trauma to this eye one week before. She reported episodes of right eyelid swelling of spontaneous resolution since the occurrence of a traumatic brain injury 5 years ago. Ophthalmological examination showed a soft and painless eyelid edema of the right eye. Brain computed tomography showed an area of bone discontinuity of the orbital roof with brain herniation and a CSF leak into the eyelid (blepharocele). Magnetic resonance confirmed the result of TC and revealed an area of frontal encephalomalacia. Ibuprofen (800 mg/day) was prescribed, with complete resolution within 20 days. She was evaluated by Neurosurgery with no indication of surgery due to the resolution of the edema and absence of symptoms. Blepharocele is a rare entity that should be considered in the differential diagnosis of unilateral eyelid edema. It can be secondary to an orbital fracture or congenital lesion. PMID:28848682

Injection of demineralized bone matrix with bone marrow concentrate improves healing in unicameral bone cyst.

PubMed

Di Bella, Claudia; Dozza, Barbara; Frisoni, Tommaso; Cevolani, Luca; Donati, Davide

2010-11-01

Unicameral bone cysts are benign lesions that usually spontaneously regress with skeletal maturity; however, the high risk of pathologic fractures often justifies treatment that could reinforce a weakened bone cortex. Various treatments have been proposed but there is no consensus regarding the best procedure. We compared the healing rates and failures of two methods of cure based on multiple injections of corticosteroid or a single injection of demineralized bone matrix (DBM) in association with bone marrow concentrate (BMC). We retrospectively reviewed 184 patients who had one of the two treatments for unicameral bone cysts with cortical erosion. Clinical records were reviewed for treatment failures and radiographs for healing in all patients. The minimum followup was 12 months for the Steroids Group (mean, 48 months; range, 12-120 months) and 12 months for the DBM + BMC Group (mean, 20 months; range, 12-28 months). After one treatment we observed a lower healing rate of cysts treated with multiple injections of steroids compared with the healing after the first injection of DBM + BMC (21% versus 58%, respectively). At last followup, 38% healed with steroids and 71% with DBM + BMC. The rate of failure after one steroid injection was higher than after a single injection of BDM + BMC (63% versus 24%, respectively). We observed no difference in fracture rates after treatment between the two groups. A single injection of DBM added with autologous bone marrow concentrate appears to provide a higher healing rate with a lower number of failures compared with a single injection of steroids.

Surfactant Based Enhanced Oil Recovery and Foam Mobility Control

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

George J. Hirasaki; Clarence A. Miller; Gary A. Pope

2005-07-01

Surfactant flooding has the potential to significantly increase recovery over that of conventional waterflooding. The availability of a large number of surfactant structures makes it possible to conduct a systematic study of the relation between surfactant structure and its efficacy for oil recovery. A combination of two surfactants was found to be particularly effective for application in carbonate formations at low temperature. A formulation has been designed for a particular field application. The addition of an alkali such as sodium carbonate makes possible in situ generation of surfactant and significant reduction of surfactant adsorption. In addition to reduction of interfacialmore » tension to ultra-low values, surfactants and alkali can be designed to alter wettability to enhance oil recovery. The design of the process to maximize the region of ultra-low IFT is more challenging since the ratio of soap to synthetic surfactant is a parameter in the conditions for optimal salinity. Compositional simulation of the displacement process demonstrates the interdependence of the various components for oil recovery. An alkaline surfactant process is designed to enhance spontaneous imbibition in fractured, oil-wet, carbonate formations. It is able to recover oil from dolomite core samples from which there was no oil recovery when placed in formation brine. Mobility control is essential for surfactant EOR. Foam is evaluated to improve the sweep efficiency of surfactant injected into fractured reservoirs. UTCHEM is a reservoir simulator specially designed for surfactant EOR. It has been modified to represent the effects of a change in wettability. Simulated case studies demonstrate the effects of wettability.« less

Useful Interplay Between Spontaneous ADR Reports and Electronic Healthcare Records in Signal Detection.

PubMed

Pacurariu, Alexandra C; Straus, Sabine M; Trifirò, Gianluca; Schuemie, Martijn J; Gini, Rosa; Herings, Ron; Mazzaglia, Giampiero; Picelli, Gino; Scotti, Lorenza; Pedersen, Lars; Arlett, Peter; van der Lei, Johan; Sturkenboom, Miriam C; Coloma, Preciosa M

2015-12-01

Spontaneous reporting systems (SRSs) remain the cornerstone of post-marketing drug safety surveillance despite their well-known limitations. Judicious use of other available data sources is essential to enable better detection, strengthening and validation of signals. In this study, we investigated the potential of electronic healthcare records (EHRs) to be used alongside an SRS as an independent system, with the aim of improving signal detection. A signal detection strategy, focused on a limited set of adverse events deemed important in pharmacovigilance, was performed retrospectively in two data sources-(1) the Exploring and Understanding Adverse Drug Reactions (EU-ADR) database network and (2) the EudraVigilance database-using data between 2000 and 2010. Five events were considered for analysis: (1) acute myocardial infarction (AMI); (2) bullous eruption; (3) hip fracture; (4) acute pancreatitis; and (5) upper gastrointestinal bleeding (UGIB). Potential signals identified in each system were verified using the current published literature. The complementarity of the two systems to detect signals was expressed as the percentage of the unilaterally identified signals out of the total number of confirmed signals. As a proxy for the associated costs, the number of signals that needed to be reviewed to detect one true signal (number needed to detect [NND]) was calculated. The relationship between the background frequency of the events and the capability of each system to detect signals was also investigated. The contribution of each system to signal detection appeared to be correlated with the background incidence of the events, being directly proportional to the incidence in EU-ADR and inversely proportional in EudraVigilance. EudraVigilance was particularly valuable in identifying bullous eruption and acute pancreatitis (71 and 42 % of signals were correctly identified from the total pool of known associations, respectively), while EU-ADR was most useful in identifying hip fractures (60 %). Both systems contributed reasonably well to identification of signals related to UGIB (45 % in EudraVigilance, 40 % in EU-ADR) but only fairly for signals related to AMI (25 % in EU-ADR, 20 % in EudraVigilance). The costs associated with detection of signals were variable across events; however, it was often more costly to detect safety signals in EU-ADR than in EudraVigilance (median NNDs: 7 versus 5). An EHR-based system may have additional value for signal detection, alongside already established systems, especially in the presence of adverse events with a high background incidence. While the SRS appeared to be more cost effective overall, for some events the costs associated with signal detection in the EHR might be justifiable.

Pregnancy-associated osteoporosis with a heterozygous deactivating LDL receptor-related protein 5 (LRP5) mutation and a homozygous methylenetetrahydrofolate reductase (MTHFR) polymorphism.

PubMed

Cook, Fiona J; Mumm, Steven; Whyte, Michael P; Wenkert, Deborah

2014-04-01

Pregnancy-associated osteoporosis (PAO) is a rare, idiopathic disorder that usually presents with vertebral compression fractures (VCFs) within 6 months of a first pregnancy and delivery. Spontaneous improvement is typical. There is no known genetic basis for PAO. A 26-year-old primagravida with a neonatal history of unilateral blindness attributable to hyperplastic primary vitreous sustained postpartum VCFs consistent with PAO. Her low bone mineral density (BMD) seemed to respond to vitamin D and calcium therapy, with no fractures after her next successful pregnancy. Investigation of subsequent fetal losses revealed homozygosity for the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism associated both with fetal loss and with osteoporosis (OP). Because her neonatal unilateral blindness and OP were suggestive of loss-of-function mutation(s) in the gene that encodes LDL receptor-related protein 5 (LRP5), LRP5 exon and splice site sequencing was also performed. This revealed a unique heterozygous 12-bp deletion in exon 21 (c.4454_4465del, p.1485_1488del SSSS) in the patient, her mother and sons, but not her father or brother. Her mother had a normal BMD, no history of fractures, PAO, ophthalmopathy, or fetal loss. Her two sons had no ophthalmopathy and no skeletal issues. Her osteoporotic father (with a family history of blindness) and brother had low BMDs first documented at ages ∼40 and 32 years, respectively. Serum biochemical and bone turnover studies were unremarkable in all subjects. We postulate that our patient's heterozygous LRP5 mutation together with her homozygous MTHFR polymorphism likely predisposed her to low peak BMD. However, OP did not cosegregate in her family with the LRP5 mutation, the homozygous MTHFR polymorphism, or even the combination of the two, implicating additional genetic or nongenetic factors in her PAO. Nevertheless, exploration for potential genetic contributions to PAO may explain part of the pathogenesis of this enigmatic disorder and identify some at-risk women. © 2013 American Society for Bone and Mineral Research.

Subclinical hypervitaminosis A causes fragile bones in rats.

PubMed

Johansson, S; Lind, P M; Hakansson, H; Oxlund, H; Orberg, J; Melhus, H

2002-12-01

Excessive intake of vitamin A has been associated with an increased risk of hip fracture in humans. This finding has raised the question of whether long-term intake of relatively moderate doses ("subclinical" hypervitaminosis A) contributes to fracture risk. Although it has been known for more than half a century that toxic doses of vitamin A lead to spontaneous fractures in rats, the lowest intake that induces adverse effects is not known, and the result of exposure to excessive doses that do not cause general toxicity has been rarely investigated. In this study, mature female rats were fed a standard diet with 12 IU vitamin A/g pellet (control, C), or standard diet supplemented with either 120 IU ("10 x C") or 600 IU ("50 x C") vitamin A/g pellet for 12 weeks. Fifteen animals were included in each group. The supplemented diets correspond to a vitamin A intake of approximately 1800 IU/day and 9000 IU/day, respectively. The latter dose is about one third of that previously reported to cause skeletal lesions. At the end of the study, serum retinyl esters were elevated 4- (p < 0.01) and 20-fold (p < 0.001) and the total amount of liver retinoid had increased 3- (p < 0.001) and 7-fold (p < 0.001) in the 10 x C and 50 x C group, respectively. The animals showed no clinical signs of general toxicity, and there were no significant bone changes in the 10 x C group. However, in the 50 x C group, a characteristic thinning of the cortex (cortical area -6.5% [p < 0.001]) and reduction of the diameter of the long bones were evident (bone cross-sectional area -7.2% [p < 0.01] at the midshaft and -11.0% [p < 0.01] at the metaphysis), as measured by peripheral quantitative computed tomography. In agreement with these data and a decreased polar strength strain index (-14.0%, p < 0.01), the three-point bending breaking force of the femur was reduced by 10.3% (p < 0.01) in the 50 x C group. These data indicate that the negative skeletal effects appear at a subchronic vitamin A intake of somewhere between 10 and 50 times the standard diet. This level is considerably lower than previously reported. Our results suggest that long-term ingestion of modest excesses of vitamin A may contribute to fracture risk. Copyright 2002 by Elsevier Science Inc.

Fan-head shear rupture mechanism as a source of off-fault tensile cracking

NASA Astrophysics Data System (ADS)

Tarasov, Boris

2016-04-01

This presentation discusses the role of a recently identified fan-head shear rupture mechanism [1] in the creation of off-fault tensile cracks observed in earthquake laboratory experiments conducted on brittle photoelastic specimens [2,3]. According to the fan-mechanism the shear rupture propagation is associated with consecutive creation of small slabs in the fracture tip which, due to rotation caused by shear displacement of the fracture interfaces, form a fan-structure representing the fracture head. The fan-head combines such unique features as: extremely low shear resistance (below the frictional strength) and self-sustaining tensile stress intensification along one side of the interface. The variation of tensile stress within the fan-head zone is like this: it increases with distance from the fracture tip up to a maximum value and then decreases. For the initial formation of the fan-head high local stresses corresponding to the fracture strength should be applied in a small area, however after completions of the fan-head it can propagate dynamically through the material at low shear stresses (even below the frictional strength). The fan-mechanism allows explaining all unique features associated with the off-fault cracking process observed in photoelastic experiments [2,3]. In these experiments spontaneous shear ruptures were nucleated in a bonded, precut, inclined and pre-stressed interface by producing a local pressure pulse in a small area. Isochromatic fringe patterns around a shear rupture propagating along bonded interface indicate the following features of the off-fault tensile crack development: tensile cracks nucleate and grow periodically along one side of the interface at a roughly constant angle (about 80 degrees) relative to the shear rupture interface; the tensile crack nucleation takes place some distance behind the rupture tip; with distance from the point of nucleation tensile cracks grow up to a certain length within the rupture head zone; behind this zone static microcracks are left in the wake of the propagating rupture. Unfortunately, the modern technology used in these experiments is not able to identify the shear rupture mechanism itself operated within the narrow rupture interface. However, a special analysis of side effects accompanying the shear rupture propagation (including the off-fault tensile cracking) allows supposing that the failure process was governed by the fan-mechanism. 1. Tarasov, B.G. 2014. Hitherto unknown shear rupture mechanism as a source of instability in intact hard rocks at highly confined compression. Tectonophysics, 621, 69-84. 2. Griffith, W.A., Rosakis, A., Pollard, D.D. and Ko, C.W., 2009. Dynamic rupture experiments elucidate tensile crack development during propagating earthquake ruptures, Geology, pp 795-798. 3. Ngo, D., Huang, Y., Rosakis, A., Griffith, W.A., Pollard D. 2012. Off-fault tensile cracks: A link between geological fault observations, lab experiments, and dynamic rupture models. Journal of Geophysical Research, vol. 117, B01307, doi: 10.1029/2011JB008577 (2012).

Chemical and mineralogical characterization of highly and less reactive coal from Northern Natal and Venda-Pafuri coalfields in South Africa

NASA Astrophysics Data System (ADS)

Kataka, M. O.; Matiane, A. R.; Odhiambo, B. D. O.

2018-01-01

Spontaneous combustion of coal is a major hazard associated with the coal mining industry over centuries. It also a major cause of underground fires in South African collieries and in opencast operations, spoil heaps and stockpiles. Spontaneous combustion incidents are manifested in all major aspects of coal mining namely, underground mining, surface mining, including during sea-borne transportation, storage and waste disposal. Previous studies indicate that there are various factors (both intrinsic and extrinsic) that influence the spontaneous combustion of coals. This paper characterizes highly reactive coal from the Vryheid coalfields and less reactive coal from at Venda-Pafuri coalfield, to identify and delineate some intrinsic coal parameters that are considered to be most critical in terms of heat 'generation' and relationships between the two coals types by tracing their similarities and differences in their spontaneous combustion parameters. Various tests were carried out to characterize these coals in terms of their intrinsic properties, namely: ultimate, proximate, petrographic analysis and Glasser spontaneous tests. The ultimate and proximate analysis showed that spontaneous coal has high contents of carbon, oxygen, and volatile matter as compared to non-spontaneous coal, making it more susceptible to spontaneous combustion. Non-spontaneous coal has higher ash content than the spontaneous coal. Furthermore, the petrographic analysis showed that spontaneous coal has high total reactivity compared to the non-spontaneous coal. Results from Glasser spontaneous test indicate that spontaneous coal absorbs more oxygen than non-spontaneous coal, which explains why spontaneous coal is more susceptible to spontaneous combustion. High reactive coal has low values of critical self-heating temperature (CSHT), indicating that this coal has potential of spontaneous ignition.

Effect of Random Natural Fractures on Hydraulic Fracture Propagation Geometry in Fractured Carbonate Rocks

NASA Astrophysics Data System (ADS)

Liu, Zhiyuan; Wang, Shijie; Zhao, Haiyang; Wang, Lei; Li, Wei; Geng, Yudi; Tao, Shan; Zhang, Guangqing; Chen, Mian

2018-02-01

Natural fractures have a significant influence on the propagation geometry of hydraulic fractures in fractured reservoirs. True triaxial volumetric fracturing experiments, in which random natural fractures are created by placing cement blocks of different dimensions in a cuboid mold and filling the mold with additional cement to create the final test specimen, were used to study the factors that influence the hydraulic fracture propagation geometry. These factors include the presence of natural fractures around the wellbore, the dimension and volumetric density of random natural fractures and the horizontal differential stress. The results show that volumetric fractures preferentially formed when natural fractures occurred around the wellbore, the natural fractures are medium to long and have a volumetric density of 6-9%, and the stress difference is less than 11 MPa. The volumetric fracture geometries are mainly major multi-branch fractures with fracture networks or major multi-branch fractures (2-4 fractures). The angles between the major fractures and the maximum horizontal in situ stress are 30°-45°, and fracture networks are located at the intersections of major multi-branch fractures. Short natural fractures rarely led to the formation of fracture networks. Thus, the interaction between hydraulic fractures and short natural fractures has little engineering significance. The conclusions are important for field applications and for gaining a deeper understanding of the formation process of volumetric fractures.

Long-term consequences of anorexia nervosa.

PubMed

Meczekalski, Blazej; Podfigurna-Stopa, Agnieszka; Katulski, Krzysztof

2013-07-01

Anorexia nervosa (AN) is a psychiatric disorder that occurs mainly in female adolescents and young women. The obsessive fear of weight gain, critically limited food intake and neuroendocrine aberrations characteristic of AN have both short- and long-term consequences for the reproductive, cardiovascular, gastrointestinal and skeletal systems. Neuroendocrine changes include impairment of gonadotropin releasing-hormone (GnRH) pulsatile secretion and changes in neuropeptide activity at the hypothalamic level, which cause profound hypoestrogenism. AN is related to a decrease in bone mass density, which can lead to osteopenia and osteoporosis and a significant increase in fracture risk in later life. Rates of birth complications and low birth weight may be higher in women with previous AN. The condition is associated with fertility problems, unplanned pregnancies and generally negative attitudes to pregnancy. During pregnancy, women with the condition have higher rates of hyperemesis gravidarum, anaemia and obstetric complications, as well as impaired weight gain and compromised intrauterine foetal growth. It is reported that 80% of AN patients are affected by a cardiac complications such as sinus bradycardia, a prolonged QT interval on electrocardiography, arrythmias, myocardial mass modification and hypotension. A decrease in bone mineral density (BMD) is one of the most important medical consequences of AN. Reduced BMD may subsequently lead to a three- to seven-fold increased risk of spontaneous fractures. Untreated AN is associated with a significant increase in the risk of death. Better detection and sophisticated therapy should prevent the long-term consequences of this disorder. The aims of treatment are not only recovery but also prophylaxis and relief of the long-term effects of this disorder. Further investigations of the long-term disease risk are needed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Transpubic access using pedicle tubularized labial urethroplasty for the treatment of female urethral strictures associated with urethrovaginal fistulas secondary to pelvic fracture.

PubMed

Xu, Yue-Min; Sa, Ying-Long; Fu, Qiang; Zhang, Jiong; Xie, Hong; Jin, San-Bao

2009-07-01

Female urethral injury is rare, and there is no accepted standard approach for the repair of urethral strictures. To evaluate the efficacy of transpubic access using pedicle tubularized labial urethroplasty for urethral reconstruction in female patients with urethral obliterative strictures and urethrovaginal fistulas. Between January 1996 and December 2006, eight cases of female urethral strictures associated with urethrovaginal fistulas were treated using pedicle labial skin flaps. A flap of approximately 3x3.5x3cm of the labia minora or majora with its vascular pedicle was tubularized over an 18-22 Fr fenestrated silicone stent to create a neourethra. This technique was used in five women. Two flaps, approximately 1.5-3.5 cm, were taken from bilateral labia minora or majora and were pieced together to create a neourethra. This technique was used in three patients. We performed voiding cystourethrography and uroflowmetry to assess postoperative results. The patients were followed up for 10-118 mo (mean 48.25 mo) after the procedure. There were no postoperative complications. Two patients complained of dysuria, which resolved spontaneously after 2 wk. One patient experienced stress incontinence that resolved after 4 wk. At 3-mo follow-up, one patient complained of difficulty voiding; the urinary peak flow was 13 ml/s, and the patient was treated successfully with urethral dilation. All other patients had normal micturition following catheter removal. Pedicle labial urethroplasty is a reliable technique for the repair of extensive urethral damage, and a transpubic surgical approach provides wide and excellent exposure for the management of complex obliterative urethral strictures and urethrovaginal fistulas secondary to pelvic fracture.

Direct medical costs attributable to peripheral fractures in Canadian post-menopausal women.

PubMed

Bessette, L; Jean, S; Lapointe-Garant, M-P; Belzile, E L; Davison, K S; Ste-Marie, L G; Brown, J P

2012-06-01

This study determined the cost of treating fractures at osteoporotic sites (except spine fractures) for the year following fracture. While the average cost of treating a hip fracture was the highest of all fractures ($46,664 CAD per fracture), treating other fractures also accounted for significant expenditures ($5,253 to $10,410 CAD per fracture). This study aims to determine the mean direct medical cost of treating fractures at peripheral osteoporotic sites in the year post-fracture (through 2 years post-hip fracture). Health administrative databases from the province of Quebec, Canada were used to estimate the cost of treating peripheral fractures at osteoporotic sites for the year following fracture (through 2 years for hip fractures). Included in costs analyses were physician claims, emergency and outpatient clinic costs, hospitalization costs, and subsequent costs for treatment of complications. A total of 15,827 patients (mean age 72 years) who suffered one fracture at an osteoporotic site had data for analyses. Hip/femur fractures had the highest rate of hospital stays related to fracture (91%) and the highest rate of hospital stays associated with a post-fracture complication (8%). In the year following fracture, the mean (SD) costs (2009 Canadian dollars) of treating acute fractures and post-fracture complications were: hip/femur fracture $46,664 ($43,198), wrist fracture $5,253 ($18,982), and fractures at other peripheral sites $10,410 ($27,641). The average (SD) cost of treating post-fracture complications at the hip/femur in the second year post-fracture was $1,698 ($12,462). Hospitalizations associated with the fracture accounted for 88% of the total cost of fracture treatment. The treatment of hip fractures accounts for a significant proportion of the costs associated with the treatment of peripheral osteoporotic fractures. Interventions to reduce the incidence of fractures, particularly hip fractures, would result in significant cost savings to the health care system and would preserve quality of life in many patients.

Diverse attitudes to and understandings of spontaneous awakening trials: results from a statewide quality improvement collaborative*.

PubMed

Miller, Melissa A; Krein, Sarah L; George, Christine T; Watson, Sam R; Hyzy, Robert C; Iwashyna, Theodore J

2013-08-01

Spontaneous awakening trials (SATs) improve outcomes in mechanically ventilated patients, but implementation remains erratic. We examined variation in reported practice, prevalence of attitudes and fears regarding spontaneous awakening trials, and organizational practices associated with routine implementation of spontaneous awakening trials in an ICU quality improvement collaborative. Written survey. Michigan Health and Hospital Association's Keystone ICU, a quality improvement collaborative of 73 hospitals. Attendees of the yearly Keystone ICU meeting, January 2011, including nurses, physicians, hospital administrators, and other healthcare professionals. Respondents were asked about institutional characteristics, spontaneous awakening trial practice, attitudes and barriers regarding spontaneous awakening trials, and organizational cultural characteristics that might influence SAT practice. The association of organizational cultural characteristics and attitudes with reported spontaneous awakening trial use was evaluated using logistic regression. Three hundred nineteen participants attended the meeting. The survey response rate was 83.4%. Respondents reported wide variation in approach to spontaneous awakening trial performance and patient selection. 48.6% of respondents reported regular spontaneous awakening trial use, defined as greater than 75% of mechanically ventilated patients undergoing spontaneous awakening trials each day. In bivariable analysis, addressing sedation goals routinely in rounds and having spontaneous awakening trials as part of unit culture were positively associated with regular spontaneous awakening trial use, whereas the perception that spontaneous awakening trials increased short-term adverse effects, staff fears of spontaneous awakening trials, and the perception that spontaneous awakening trials are hard work were negatively associated with regular spontaneous awakening trial use. In multivariable analysis, only addressing sedation in rounds (odds ratio, 2.85 [95% CI, 1.55-5.23]), incorporation of spontaneous awakening trials into unit culture (odds ratio, 3.36 [95% CI, 1.75-6.43]), and the perception that spontaneous awakening trials are hard work (odds ratio, 0.53 [95% CI, 0.30-0.96]) remained statistically significantly associated with regular spontaneous awakening trial use. Respondents in managerial positions were less likely to perceive spontaneous awakening trials as hard work (odds ratio, 0.44 [95% CI, 0.22-0.85]). Even in a motivated statewide quality improvement collaborative, spontaneous awakening trial practice varies widely and concerns persist regarding spontaneous awakening trials. Cultural practices may counteract the effect of concerns regarding spontaneous awakening trials and are associated with increased performance of this beneficial intervention. Patient selection should be a focus for continuing medical education. Differences in perception of work between management and staff may also be a focus for improved communication.

Basic principles of fracture treatment in children.

PubMed

Ömeroğlu, Hakan

2018-04-01

This review aims to summarize the basic treatment principles of fractures according to their types and general management principles of special conditions including physeal fractures, multiple fractures, open fractures, and pathologic fractures in children. Definition of the fracture is needed for better understanding the injury mechanism, planning a proper treatment strategy, and estimating the prognosis. As the healing process is less complicated, remodeling capacity is higher and non-union is rare, the fractures in children are commonly treated by non-surgical methods. Surgical treatment is preferred in children with multiple injuries, in open fractures, in some pathologic fractures, in fractures with coexisting vascular injuries, in fractures which have a history of failed initial conservative treatment and in fractures in which the conservative treatment has no/little value such as femur neck fractures, some physeal fractures, displaced extension and flexion type humerus supracondylar fractures, displaced humerus lateral condyle fractures, femur, tibia and forearm shaft fractures in older children and adolescents and unstable pelvis and acetabulum fractures. Most of the fractures in children can successfully be treated by non-surgical methods.

Pathological Calcification and Ossification in Relation to Leriche and Policard's Theory

PubMed Central

Jones, Watson; Roberts, R. E.

1933-01-01

(1) Pathology of calcification and ossification.—The Leriche-Policard theories. Hyperæmia of bone causes decalcification. Reduced blood supply causes sclerosis. Diminution of vascularity of fibrous tissue causes calcification. Excess of calcium, adequate blood supply and fibroblasts give rise to bone anywhere. Subperiosteal ossification. “Myositis ossificans.” (2) Radiological significance of density of bone shadows.—Decalcification of disuse, of infections, of neoplasms. Traumatic and infective scquestra. Evidence that a fragment of bone is avascular. (3) Hyperæmic decalcification of bone.—Delayed and non-union of fractures. Kummel's disease. Spontaneous hyperæmic dislocation of the atlas. Hyperæmic decalcification and nephrolithiasis. (4) Anæmic sclerosis of bone.—Syphilitic bone disease. Malignant bone disease. Fragility of sclerosed bone—Paget's, Kienboch's, Kohler's and Panner's, Albers-Schönberg's diseases. (5) Pathological calcification.—Calcification of supraspinatus tendon. Calcification of tumours—angioma, hæmatoma, and thrombosed vessels, lipoma, cysts, etc. Calcification of semilunar cartilages and intervertebral discs. (6) Pathological ossification.—Ossification of tendons. Ossification of semilunar cartilages. PMID:19989304

Gene Addition Strategies for β-Thalassemia and Sickle Cell Anemia.

PubMed

Dong, Alisa C; Rivella, Stefano

2017-01-01

Beta-thalassemia and sickle cell anemia are two of the most common diseases related to the hemoglobin protein. In these diseases, the beta-globin gene is mutated, causing severe anemia and ineffective erythropoiesis. Patients can additionally present with a number of life-threatening co-morbidities, such as stroke or spontaneous fractures. Current treatment involves transfusion and iron chelation; allogeneic bone marrow transplant is the only curative option, but is limited by the availability of matching donors and graft-versus-host disease. As these two diseases are monogenic diseases, they make an attractive setting for gene therapy. Gene therapy aims to correct the mutated beta-globin gene or add back a functional copy of beta- or gamma-globin. Initial gene therapy work was done with oncoretroviral vectors, but has since shifted to lentiviral vectors. Currently, there are a few clinical trials underway to test the curative potential of some of these lentiviral vectors. This review will highlight the work done thus far, and present the challenges still facing gene therapy, such as genome toxicity concerns and achieving sufficient transgene expression to cure those with the most severe forms of thalassemia.

Acute intraoperative reactions during the injection of calcium sulfate bone cement for the treatment of unicameral bone cysts: a review of four cases.

PubMed

Nystrom, Lukas; Raw, Robert; Buckwalter, Joseph; Morcuende, Jose A

2008-01-01

Unicameral bone cysts can predispose patients to pathologic fracture and deformities of growth. Treatment options vary from continuous decompression with transcortical placement of a cannulated screw to percutaneous aspiration and injection of medical-grade calcium sulfate. From 2005 to 2007, we treated 22 patients with unicameral bone cysts using aspiration and injection of calcium sulfate. Three patients experienced acute laryngospasm and one patient developed tachyarrhythmia, temporarily, associated with injection of calcium sulfate. All reactions occurred in patients under age 18 without predisposing risk factors and resolved spontaneously with supportive care. Although the mechanism is unclear, we hypothesize that these reactions are either due to the nociceptive stimulus of the calcium sulfate injection or a systemic calcium bolus. Clinicians using this product for this indication should be aware that such reactions may occur. We suggest endotracheal intubation and communication to the anesthesiologist about the time of the injection in preparation for these idiopathic responses. Further research is necessary to determine exactly how this reaction occurs and how it can be avoided.

Acute Intraoperative Reactions During the Injection of Calcium Sulfate Bone Cement for the Treatment of Unicameral Bone Cysts: A Review of Four Cases

PubMed Central

Nystrom, Lukas; Raw, Robert; Buckwalter, Joseph; Morcuende, Jose A.

2008-01-01

Unicameral bone cysts can predispose patients to pathologic fracture and deformities of growth. Treatment options vary from continuous decompression with transcortical placement of a cannulated screw to percutaneous aspiration and injection of medical-grade calcium sulfate. From 2005 to 2007, we treated 22 patients with unicameral bone cysts using aspiration and injection of calcium sulfate. Three patients experienced acute laryngospasm and one patient developed tachyarrhythmia, temporarily, associated with injection of calcium sulfate. All reactions occurred in patients under age 18 without predisposing risk factors and resolved spontaneously with supportive care. Although the mechanism is unclear, we hypothesize that these reactions are either due to the nociceptive stimulus of the calcium sulfate injection or a systemic calcium bolus. Clinicians using this product for this indication should be aware that such reactions may occur. We suggest endotracheal intubation and communication to the anesthesiologist about the time of the injection in preparation for these idiopathic responses. Further research is necessary to determine exactly how this reaction occurs and how it can be avoided. PMID:19223954

Diagnosis of Bell palsy with gadolinium magnetic resonance imaging.

PubMed

Becelli, R; Perugini, M; Carboni, A; Renzi, G

2003-01-01

Bell palsy is a condition resulting from a peripheral edematous compression on the nervous fibers of the facial nerve. This pathological condition often has clinical characteristics of no importance and spontaneously disappears in a short time in a high percentage of cases. Facial palsy concerning cranial nerve VII can also be caused by other conditions such as mastoid fracture, acoustic neurinoma, tumor spread to the temporal lobe (e.g., cholesteatoma), neoformation of the parotid gland, Melkersson-Rosenthal syndrome, and Ramsay-Hunt syndrome. Therefore, it is important to adopt an accurate diagnostic technique allowing the rapid detection of Bell palsy and the exclusion of causes of facial paralysis requiring surgical treatment. Magnetic resonance imaging (MRI) with medium contrast of the skull shows a marked increase in revealing lesions, even of small dimensions, inside the temporal bone and at the cerebellopontine angle. The authors present a clinical case to show the important role played by gadolinium MRI in reaching a diagnosis of Bell palsy in the differential diagnosis of the various conditions that determine paralysis of the facial nerve and in selecting the most suitable treatment or surgery to be adopted.

[Airway management in a man with ankylosing spondylitis].

PubMed

Gil, S; Jamart, V; Borrás, R; Miranda, A

2007-02-01

We report a case of difficult airway management in a 41-year-old man with ankylosing spondylitis who was scheduled for total left hip replacement surgery. After several failed attempts to achieve regional anesthesia, we converted to general anesthesia with orotracheal intubation using a fiberoptic bronchoscope. Ankylosing spondylitis leads to fibrosis, ossification, and ankylosis along the spinal column and sacroiliac articulations. Cervical column and atlantooccipital articulation mobility are reduced and in severe cases the cervical vertebrae become fixed in a flexed position. This portion of the spine is also the most susceptible to fracture, particularly in hyperextension, an event that could lead to damage to the cervical spinal cord during maneuvers to manage the airway. Patients with this condition may also have temporomandibular joint involvement, further complicating airway management. We report the case of a patient with ankylosing spondylitis with fixation along the entire spine. The airway was managed by intubation with a fiberoptic bronchoscope. Spontaneous ventilation was maintained during the maneuver, and sedation was achieved with perfusion of remifentanil as the only anesthetic agent following failure of intradural anesthesia.

Explosively generated shock wave processing of metal powders by instrumented detonics

NASA Astrophysics Data System (ADS)

Sharma, A. D.; Sharma, A. K.; Thakur, N.

2013-06-01

The highest pressures generated by dynamic processes resulting either from high velocity impact or by spontaneous release of high energy rate substances in direct contact with a metal find superior applications over normal mechanical means. The special feature of explosive loading to the powder materials over traditional methods is its controlled detonation pressure which directly transmits shock energy to the materials which remain entrapped inside powder resulting into several micro-structural changes and hence improved mechanical properties. superalloy powders have been compacted nearer to the theoretical density by shock wave consolidation. In a single experimental set-up, compaction of metal powder and measurement of detonation velocity have been achieved successfully by using instrumented detonics. The thrust on the work is to obtain uniform, crack-free and fracture-less compacts of superalloys having intact crystalline structure as has been examined from FE-SEM, XRD and mechanical studies. Shock wave processing is an emerging technique and receiving much attention of the materials scientists and engineers owing to its excellent advantages over traditional metallurgical methods due to short processing time, scaleup advantage and controlled detonation pressure.

Old treatments for new insights and strategies: proposed management in adults and children with alkaptonuria.

PubMed

Arnoux, Jean-Baptiste; Le Quan Sang, Kim-Hanh; Brassier, Anais; Grisel, Coraline; Servais, Aude; Wippf, Julien; Dubois, Sandrine; Sireau, Nicolas; Job-Deslandre, Chantal; Ranganath, Lakshminarayan; de Lonlay, Pascale

2015-09-01

Alkaptonuria (AKU) is caused by deficiency of the enzyme homogentisate 1,2 dioxygenase. It results in an accumulation of homogentisate which oxidizes spontaneously to benzoquinone acetate, a highly oxidant compound, which polymerises to a melanin-like structure, in a process called ochronosis. Asymptomatic during childhood, this accumulation will lead from the second decade of life to a progressive and severe spondylo-arthopathy, associated with multisystem involvement: osteoporosis/fractures, stones (renal, prostatic, gall bladder, salivary glands), ruptures of tendons/muscle/ligaments, renal failure and aortic valve disease. The pathophysiological mechanisms of AKU remain poorly understood, but recent advances lead us to reconsider the treatment strategy in AKU patients. Besides the supporting therapies (pain killers, anti-inflammatory drugs, physiotherapy, joints replacements and others), specific therapies have been considered (anti-oxidant, low protein diet, nitisinone), but clinical studies have failed to prove efficiency on the rheumatological lesions of the disease. Here we propose a treatment strategy for children and adults with AKU, based on a review of the latest findings on AKU and lessons from other aminoacipathies, especially tyrosinemias.

Caffeine is a risk factor for osteopenia of prematurity in preterm infants: a cohort study.

PubMed

Ali, Ebtihal; Rockman-Greenberg, Cheryl; Moffatt, Michael; Narvey, Michael; Reed, Martin; Jiang, Depeng

2018-01-22

Caffeine, the most commonly used medication in Neonatal Intensive Care Units, has calciuric and osteoclastogenic effects. To examine the association between the cumulative dose and duration of therapy of caffeine and osteopenia of prematurity, a retrospective cohort study was conducted including premature infants less than 31 weeks and birth weight less than 1500 g. Osteopenia of prematurity was evaluated using chest X-rays on a biweekly basis over 12 weeks of hospitalization. The cohort included 109 infants. 51% had osteopenia of prematurity and 8% had spontaneous rib fractures. Using the generalized linear mixed model, caffeine dose and duration of caffeine therapy showed a strong association with osteopenia of prematurity. Steroids and vitamin D were also significantly correlated with osteopenia of prematurity while diuretic use did not show a statistically significant effect. The cumulative dose and duration of therapy of caffeine, as well as steroid are associated with osteopenia of prematurity in this cohort. Future studies are needed to confirm these findings and determine the lowest dose of caffeine needed to treat effectively apnea of prematurity.

Supramolecular "Big Bang" in a Single-Ionic Surfactant/Water System Driven by Electrostatic Repulsion: From Vesicles to Micelles.

PubMed

Leclercq, Loïc; Bauduin, Pierre; Nardello-Rataj, Véronique

2017-04-11

In aqueous solution, dimethyldi-n-octylammonium chloride, [DiC 8 ][Cl], spontaneously forms dimers at low concentrations (1-10 mM) to decrease the strength of the hydrophobic-water contact. Dimers represent ideal building blocks for the abrupt edification of vesicles at 10 mM. These vesicles are fully characterized by dynamic and static light scattering, self-diffusion nuclear magnetic resonance, and freeze-fracture transmission electron microscopy. An increase in concentration leads to electrostatic repulsion between vesicles that explode into small micelles at 30 mM. These transitions are detected by means of surface tension, conductivity, and solubility of hydrophobic solutes as well as by isothermal titration microcalorimetry. These unusual supramolecular transitions emerge from the surfactant chemical structure that combines two contradictory features: (i) the double-chain structure tending to form low planar aggregates with low water solubility and (ii) the relatively short chains giving high hydrophilicity. The well-balanced hydrophilic-hydrophobic character of [DiC 8 ][Cl] is then believed to be at the origin of the unusual supramolecular sequence offering new opportunities for drug delivery systems.

High Burn-Up Spent Nuclear Fuel Vibration Integrity Study

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

Wang, Jy-An John; Wang, Hong; Jiang, Hao

2015-01-01

The Oak Ridge National Laboratory (ORNL) has developed the cyclic integrated reversible-bending fatigue tester (CIRFT) approach to successfully demonstrate the controllable fatigue fracture on high burnup (HBU) spent nuclear fuel (SNF) in a normal vibration mode. CIRFT enables examination of the underlying mechanisms of SNF system dynamic performance. Due to the inhomogeneous composite structure of the SNF system, the detailed mechanisms of the pellet-pellet and pellet-clad interactions and the stress concentration effects at the pellet-pellet interface cannot be readily obtained from a CIRFT system measurement. Therefore, finite element analyses (FEAs) are used to translate the global moment-curvature measurement into localmore » stress-strain profiles for further investigation. The major findings of CIRFT on the HBU SNF are as follows: SNF system interface bonding plays an important role in SNF vibration performance. Fuel structure contributes to SNF system stiffness. There are significant variations in stress and curvature of SNF systems during vibration cycles resulting from segment pellets and clad interactions. SNF failure initiates at the pellet-pellet interface region and appears to be spontaneous.« less

Top-down fabrication of sub-nanometre semiconducting nanoribbons derived from molybdenum disulfide sheets.

PubMed

Liu, Xiaofei; Xu, Tao; Wu, Xing; Zhang, Zhuhua; Yu, Jin; Qiu, Hao; Hong, Jin-Hua; Jin, Chuan-Hong; Li, Ji-Xue; Wang, Xin-Ran; Sun, Li-Tao; Guo, Wanlin

2013-01-01

Developments in semiconductor technology are propelling the dimensions of devices down to 10 nm, but facing great challenges in manufacture at the sub-10 nm scale. Nanotechnology can fabricate nanoribbons from two-dimensional atomic crystals, such as graphene, with widths below the 10 nm threshold, but their geometries and properties have been hard to control at this scale. Here we find that robust ultrafine molybdenum-sulfide ribbons with a uniform width of 0.35 nm can be widely formed between holes created in a MoS2 sheet under electron irradiation. In situ high-resolution transmission electron microscope characterization, combined with first-principles calculations, identifies the sub-1 nm ribbon as a Mo5S4 crystal derived from MoS2, through a spontaneous phase transition. Further first-principles investigations show that the Mo5S4 ribbon has a band gap of 0.77 eV, a Young's modulus of 300GPa and can demonstrate 9% tensile strain before fracture. The results show a novel top-down route for controllable fabrication of functional building blocks for sub-nanometre electronics.

The macroscopic delamination of thin films from elastic substrates

PubMed Central

Vella, Dominic; Bico, José; Boudaoud, Arezki; Roman, Benoit; Reis, Pedro M.

2009-01-01

The wrinkling and delamination of stiff thin films adhered to a polymer substrate have important applications in “flexible electronics.” The resulting periodic structures, when used for circuitry, have remarkable mechanical properties because stretching or twisting of the substrate is mostly accommodated through bending of the film, which minimizes fatigue or fracture. To date, applications in this context have used substrate patterning to create an anisotropic substrate-film adhesion energy, thereby producing a controlled array of delamination “blisters.” However, even in the absence of such patterning, blisters appear spontaneously, with a characteristic size. Here, we perform well-controlled experiments at macroscopic scales to study what sets the dimensions of these blisters in terms of the material properties and explain our results by using a combination of scaling and analytical methods. Besides pointing to a method for determining the interfacial toughness, our analysis suggests a number of design guidelines for the thin films used in flexible electronic applications. Crucially, we show that, to avoid the possibility that delamination may cause fatigue damage, the thin film thickness must be greater than a critical value, which we determine. PMID:19556551

Imaging of childhood torticollis due to atlanto-axial rotatory fixation.

PubMed

Maheshwaran, S; Sgouros, S; Jeyapalan, K; Chapman, S; Chandy, J; Flint, G

1995-12-01

Atlanto-axial rotatory fixation is a rare cause of childhood torticollis. It may occur spontaneously or may be associated with trauma, upper respiratory tract infection or congenital abnormality of the cervical spine. Presentation is usually with persistent torticollis and "cock robin" deformity of the neck. In this paper the radiological experience in three patients is presented. Investigations included plain radiographs, plain anteroposterior tomography, CT and MRI. Displacement of the lateral mass of the atlas and the eccentric position of the odontoid peg can be seen in the plain films. CT scan can exclude fractures and confirm atlanto-axial rotation. The superimposition of CT images is demonstrated as a way of diagnosing subluxation. MRI offers better soft tissue differentiation and allows assessment of the integrity of the transverse ligament. This has an important bearing on the prognosis and may influence surgical treatment. It is important to recognise the plain film features of this uncommon condition and confirm the diagnosis with CT or MRI. The treatment options are discussed with particular reference to long term outcome.

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.

Discrete Fracture Network Characterization of Fractured Shale Reservoirs with Implications to Hydraulic Fracturing Optimization

NASA Astrophysics Data System (ADS)

Jin, G.

2016-12-01

Shales are important petroleum source rocks and reservoir seals. Recent developments in hydraulic fracturing technology have facilitated high gas production rates from shale and have had a strong impact on the U.S. gas supply and markets. Modeling of effective permeability for fractured shale reservoirs has been challenging because the presence of a fracture network significantly alters the reservoir hydrologic properties. Due to the frequent occurrence of fracture networks, it is of vital importance to characterize fracture networks and to investigate how these networks can be used to optimize the hydraulic fracturing. We have conducted basic research on 3-D fracture permeability characterization and compartmentization analyses for fractured shale formations, which takes the advantages of the discrete fracture networks (DFN). The DFN modeling is a stochastic modeling approach using the probabilistic density functions of fractures. Three common scenarios of DFN models have been studied for fracture permeability mapping using our previously proposed techniques. In DFN models with moderately to highly concentrated fractures, there exists a representative element volume (REV) for fracture permeability characterization, which indicates that the fractured reservoirs can be treated as anisotropic homogeneous media. Hydraulic fracturing will be most effective if the orientation of the hydraulic fracture is perpendicular to the mean direction of the fractures. A DFN model with randomized fracture orientations, on the other hand, lacks an REV for fracture characterization. Therefore, a fracture permeability tensor has to be computed from each element. Modeling of fracture interconnectivity indicates that there exists no preferred direction for hydraulic fracturing to be most effective oweing to the interconnected pathways of the fracture network. 3-D fracture permeability mapping has been applied to the Devonian Chattanooga Shale in Alabama and the results suggest that an REV exist for fluid flow and transport modeling at element sizes larger than 200 m. Fracture pathway analysis indicates that hydraulic fracturing can be equally effective for hydrocarbon fluid/gas exploration as long as its orientation is not aligned with that of the regional system fractures.

Does Spontaneous Favorability to Power (vs. Universalism) Values Predict Spontaneous Prejudice and Discrimination?

PubMed

Souchon, Nicolas; Maio, Gregory R; Hanel, Paul H P; Bardin, Brigitte

2017-10-01

We conducted five studies testing whether an implicit measure of favorability toward power over universalism values predicts spontaneous prejudice and discrimination. Studies 1 (N = 192) and 2 (N = 86) examined correlations between spontaneous favorability toward power (vs. universalism) values, achievement (vs. benevolence) values, and a spontaneous measure of prejudice toward ethnic minorities. Study 3 (N = 159) tested whether conditioning participants to associate power values with positive adjectives and universalism values with negative adjectives (or inversely) affects spontaneous prejudice. Study 4 (N = 95) tested whether decision bias toward female handball players could be predicted by spontaneous attitude toward power (vs. universalism) values. Study 5 (N = 123) examined correlations between spontaneous attitude toward power (vs. universalism) values, spontaneous importance toward power (vs. universalism) values, and spontaneous prejudice toward Black African people. Spontaneous positivity toward power (vs. universalism) values was associated with spontaneous negativity toward minorities and predicted gender bias in a decision task, whereas the explicit measures did not. These results indicate that the implicit assessment of evaluative responses attached to human values helps to model value-attitude-behavior relations. © 2016 The Authors. Journal of Personality Published by Wiley Periodicals, Inc.

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

The AO Pediatric Comprehensive Classification of Long Bone Fractures (PCCF).

PubMed

Joeris, Alexander; Lutz, Nicolas; Blumenthal, Andrea; Slongo, Theddy; Audigé, Laurent

2017-04-01

Background and purpose - To achieve a common understanding when dealing with long bone fractures in children, the AO Pediatric Comprehensive Classification of Long Bone Fractures (AO PCCF) was introduced in 2007. As part of its final validation, we present the most relevant fracture patterns in the upper extremities of a representative population of children classified according to the PCCF. Patients and methods - We included children and adolescents (0-17 years old) diagnosed with 1 or more long bone fractures between January 2009 and December 2011 at the university hospitals in Bern and Lausanne (Switzerland). Patient charts were retrospectively reviewed and fractures were classified from standard radiographs. Results - Of 2,292 upper extremity fractures in 2,203 children and adolescents, 26% involved the humerus and 74% involved the forearm. In the humerus, 61%, and in the forearm, 80% of single distal fractures involved the metaphysis. In adolescents, single humerus fractures were more often epiphyseal and diaphyseal fractures, and among adolescents radius fractures were more often epiphyseal fractures than in other age groups. 47% of combined forearm fractures were distal metaphyseal fractures. Only 0.7% of fractures could not be classified within 1 of the child-specific fracture patterns. Of the single epiphyseal fractures, 49% were Salter-Harris type-II (SH II) fractures; of these, 94% occurred in schoolchildren and adolescents. Of the metaphyseal fractures, 58% showed an incomplete fracture pattern. 89% of incomplete fractures affected the distal radius. Of the diaphyseal fractures, 32% were greenstick fractures. 24 Monteggia fractures occurred in pre-school children and schoolchildren, and 2 occurred in adolescents. Interpretation - The pattern of pediatric fractures in the upper extremity can be comprehensively described according to the PCCF. Prospective clinical studies are needed to determine its clinical relevance for treatment decisions and prognostication of outcome.

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.

The AO Pediatric Comprehensive Classification of Long Bone Fractures (PCCF)

PubMed Central

Joeris, Alexander; Lutz, Nicolas; Blumenthal, Andrea; Slongo, Theddy; Audigé, Laurent

2017-01-01

Background and purpose To achieve a common understanding when dealing with long bone fractures in children, the AO Pediatric Comprehensive Classification of Long Bone Fractures (AO PCCF) was introduced in 2007. As part of its final validation, we present the most relevant fracture patterns in the upper extremities of a representative population of children classified according to the PCCF. Patients and methods We included children and adolescents (0–17 years old) diagnosed with 1 or more long bone fractures between January 2009 and December 2011 at the university hospitals in Bern and Lausanne (Switzerland). Patient charts were retrospectively reviewed and fractures were classified from standard radiographs. Results Of 2,292 upper extremity fractures in 2,203 children and adolescents, 26% involved the humerus and 74% involved the forearm. In the humerus, 61%, and in the forearm, 80% of single distal fractures involved the metaphysis. In adolescents, single humerus fractures were more often epiphyseal and diaphyseal fractures, and among adolescents radius fractures were more often epiphyseal fractures than in other age groups. 47% of combined forearm fractures were distal metaphyseal fractures. Only 0.7% of fractures could not be classified within 1 of the child-specific fracture patterns. Of the single epiphyseal fractures, 49% were Salter-Harris type-II (SH II) fractures; of these, 94% occurred in schoolchildren and adolescents. Of the metaphyseal fractures, 58% showed an incomplete fracture pattern. 89% of incomplete fractures affected the distal radius. Of the diaphyseal fractures, 32% were greenstick fractures. 24 Monteggia fractures occurred in pre-school children and schoolchildren, and 2 occurred in adolescents. Interpretation The pattern of pediatric fractures in the upper extremity can be comprehensively described according to the PCCF. Prospective clinical studies are needed to determine its clinical relevance for treatment decisions and prognostication of outcome. PMID:27882802

Mechanics in the Production of Mandibular Fractures: A Clinical, Retrospective Case-Control Study

PubMed Central

Yang, Rongtao; Li, Zhi; Li, Zubing

2016-01-01

As the mandible is susceptible to fracture, the aim of this study was to use multivariate logistic regression analysis to identify and distinguish various internal factors that may influence the location of mandibular fractures. The study included 1131 patients with maxillofacial fractures during the period from January 2000 to December 2009 to evaluate the association of mandibular fracture location (unilateral symphysis, body, angle, condylar, or bilateral condylar fractures) with various internal factors. Among the 1131 patients, 869 had mandibular fractures. Data on age, sex, soft tissue injuries, dental trauma, and maxillofacial fracture type were collected and analyzed using multivariate logistic regression. In total, 387, 210, 139, 319, and 172 patients were diagnosed with unilateral symphysis, body, angle, unilateral, or bilateral condylar fractures, respectively. The dental trauma in patients with bilateral condylar fractures differed from that in patients with unilateral condylar fractures. Patients with mandibular fracture (unilateral symphysis, body, unilateral or bilateral condylar) possessed an approximately equal risk of soft tissue injuries in the mandible. Patients with either unilateral or bilateral condylar fractures were associated with a low risk of mandibular angle fracture (OR < 1). Similarly, patients with mandibular angle fracture were associated with a low risk of unilateral or bilateral condylar fractures (OR < 1). Moreover, patients with symphysis fracture were associated with a low risk of bilateral condylar fractures (90 of 387 [23.3%], OR 0.899). By contrast, patients with bilateral condylar fractures were associated with a high risk of symphysis fracture (90 of 172 [52.3%], OR 17.38). Patients with condylar fractures, particularly those with bilateral condylar fractures, were infrequently associated with secondary mandibular fractures. Mandibular fractures tended to have less of an association with midfacial fractures. The occurrence of mandibular fractures is strongly correlated with age, sex, soft tissue injuries, dental trauma, and the pattern and position of the maxillofacial fractures in patients. PMID:26900699

Previous Fractures at Multiple Sites Increase the Risk for Subsequent Fractures: The Global Longitudinal Study of Osteoporosis in Women

PubMed Central

Gehlbach, Stephen; Saag, Kenneth G.; Adachi, Jonathan D.; Hooven, Fred H.; Flahive, Julie; Boonen, Steven; Chapurlat, Roland D.; Compston, Juliet E.; Cooper, Cyrus; Díez-Perez, Adolfo; Greenspan, Susan L.; LaCroix, Andrea Z.; Netelenbos, J. Coen; Pfeilschifter, Johannes; Rossini, Maurizio; Roux, Christian; Sambrook, Philip N.; Silverman, Stuart; Siris, Ethel S.; Watts, Nelson B.; Lindsay, Robert

2016-01-01

Previous fractures of the hip, spine, or wrist are well-recognized predictors of future fracture, but the role of other fracture sites is less clear. We sought to assess the relationship between prior fracture at 10 skeletal locations and incident fracture. The Global Longitudinal Study of Osteoporosis in Women (GLOW) is an observational cohort study being conducted in 17 physician practices in 10 countries. Women ≥ 55 years answered questionnaires at baseline and at 1 and/or 2 years (fractures in previous year). Of 60,393 women enrolled, follow-up data were available for 51,762. Of these, 17.6%, 4.0%, and 1.6% had suffered 1, 2, or ≥3 fractures since age 45. During the first 2 years of follow-up, 3149 women suffered 3683 incident fractures. Compared with women with no prior fractures, women with 1, 2, or ≥ 3 prior fractures were 1.8-, 3.0-, and 4.8-fold more likely to have any incident fracture; those with ≥3 prior fractures were 9.1-fold more likely to sustain a new vertebral fracture. Nine of 10 prior fracture locations were associated with an incident fracture. The strongest predictors of incident spine and hip fractures were prior spine fracture (hazard ratio 7.3) and hip (hazard ratio 3.5). Prior rib fractures were associated with a 2.3-fold risk of subsequent vertebral fracture, previous upper leg fracture predicted a 2.2-fold increased risk of hip fracture; women with a history of ankle fracture were at 1.8-fold risk of future fracture of a weight-bearing bone. Our findings suggest that a broad range of prior fracture sites are associated with an increased risk of incident fractures, with important implications for clinical assessments and risk model development. PMID:22113888

Expected lifetime numbers, risks, and burden of osteoporotic fractures for 50-year old Chinese women: a discrete event simulation incorporating FRAX.

PubMed

Jiang, Yawen; Ni, Weiyi

2016-11-01

This work was undertaken to provide an estimation of expected lifetime numbers, risks, and burden of fractures for 50-year-old Chinese women. A discrete event simulation model was developed to simulate the lifetime fractures of 50-year-old Chinese women at average risk of osteoporotic fracture. Main events in the model included hip fracture, clinical vertebral fracture, wrist fracture, humerus fracture, and other fracture. Fracture risks were calculated using the FRAX ® tool. Simulations of 50-year-old Chinese women without fracture risks were also carried out as a comparison to determine the burden of fractures. A 50-year-old Chinese woman at average risk of fracture is expected to experience 0.135 (95 % CI: 0.134-0.137) hip fractures, 0.120 (95 % CI: 0.119-0.122) clinical vertebral fractures, 0.095 (95 % CI: 0.094-0.096) wrist fractures, 0.079 (95 % CI: 0.078-0.080) humerus fractures, and 0.407 (95 % CI: 0.404-0.410) other fractures over the remainder of her life. The residual lifetime risk of any fracture, hip fracture, clinical vertebral fracture, wrist fracture, humerus fracture, and other fracture for a 50-year-old Chinese woman is 37.36, 11.77, 10.47, 8.61, 7.30, and 27.80 %, respectively. The fracture-attributable excess quality-adjusted life year (QALY) loss and lifetime costs are estimated at 0.11 QALYs (95 % CI: 0.00-0.22 QALYs) and US $714.61 (95 % CI: US $709.20-720.02), totaling a net monetary benefit loss of US $1,104.43 (95 % CI: US $904.09-1,304.78). Chinese women 50 years of age are at high risk of osteoporotic fracture, and the expected economic and quality-of-life burden attributable to osteoporotic fractures among Chinese women is substantial.

Characteristics of bone fractures and usefulness of micro-computed tomography for fracture detection in rabbits: 210 cases (2007-2013).

PubMed

Sasai, Hiroshi; Fujita, Daisuke; Tagami, Yukari; Seto, Eiko; Denda, Yuki; Hamakita, Hideaki; Ichihashi, Tomonori; Okamura, Kensaku; Furuya, Masaru; Tani, Hiroyuki; Sasai, Kazumi; Yamate, Jyoji

2015-06-15

To characterize bone fractures and the usefulness of micro-CT for imaging fractures in pet rabbits. Retrospective case series. 210 client-owned rabbits with bone fractures. Medical records of rabbits evaluated for bone fractures from 2007 through 2013 were examined. Information was collected on signalment and nature of fractures, and radiographic and micro-CT images of fractures were reviewed. Almost half (n = 95 [47.7%]) of fractures were in rabbits < 3 years old. Accidental fall was the most common cause. Vertebral fracture was the most common type of fracture with a nonneoplastic cause (n = 46 [23.2%]) and was most common in the L4-L7 region. The tibia was the most common site for limb fracture among all fractures with a nonneoplastic cause (45 [22.7%]). Twelve (5.7%) fractures had a neoplastic cause, and 7 of these were associated with metastatic uterine adenocarcinoma. Females were significantly more likely to have a fracture caused by neoplasia than were males. Compared with radiography, micro-CT provided more detailed fracture information, particularly for complicated fractures or structures (eg, skull, pelvic, vertebral, and comminuted limb fractures). Findings were useful for understanding the nature of fractures in pet rabbits and supported the use of micro-CT versus radiography for fracture detection and evaluation.

Investigation of the Effect of Cemented Fractures on Fracturing Network Propagation in Model Block with Discrete Orthogonal Fractures

NASA Astrophysics Data System (ADS)

Wang, Y.; Li, C. H.

2017-07-01

Researchers have recently realized that the natural fractures in shale reservoirs are often cemented or sealed with various minerals. However, the influence of cement characteristics of natural fracture on fracturing network propagation is still not well understood. In this work, laboratory-scaled experiments are proposed to prepare model blocks with discrete orthogonal fractures network with different strength of natural fracture, in order to reveal the influence of cemented natural fractures on the interactions between hydraulic fractures and natural fractures. A series of true triaxial hydraulic fracturing experiments were conducted to investigate the mechanism of hydraulic fracture initiation and propagation in model blocks with natural fractures of different cement strength. The results present different responses of interactions between hydraulic and natural fractures, which can be reflected on the pump pressure profiles and block failure morphology. For model blocks with fluctuated pump pressure curves, the communication degree of hydraulic and natural fractures is good, which is confirmed by a proposed new index of "P-SRV." The most significant finding is that too high and too low strength properties of cemented natural fracture are adverse to generate complex fracturing network. This work can help us better understand how cemented natural fractures affect the fracturing network propagation subsurface and give us reference to develop more accurate hydraulic fracturing models.

Outcome of limb fracture repair in rabbits: 139 cases (2007-2015).

PubMed

Sasai, Hiroshi; Fujita, Daisuke; Seto, Eiko; Denda, Yuki; Imai, Yutaro; Okamoto, Kanako; Okamura, Kensaku; Furuya, Masaru; Tani, Hiroyuki; Sasai, Kazumi

2018-02-15

OBJECTIVE To evaluate outcome of limb fracture repair in rabbits. DESIGN Retrospective case series. ANIMALS 139 client-owned rabbits with limb fractures treated between 2007 and 2015. PROCEDURES Medical records were reviewed for information on fracture location, fracture treatment, and time to fracture healing. RESULTS 25 rabbits had fractures involving the distal aspects of the limbs (ie, metacarpal or metatarsal bones, phalanges, and calcaneus or talus). Fractures were treated in 23 of these 25 rabbits (external coaptation, n = 17; external skeletal fixation, 4; and intramedullary pinning, 2) and healed in all 23, with a median healing time of 28 days (range, 20 to 45 days). One hundred ten rabbits had long bone fractures, and fractures were treated in 100 of the 110 (external skeletal fixation, n = 89; bone plating, 1; intramedullary pinning, 3; and external coaptation, 7). The percentage of fractures that healed was significantly lower for open (14/18) than for closed (26/26) tibial fractures and was significantly lower for femoral (19/26) and treated humeral (4/6) fractures than for radial (23/24) or closed tibial (26/26) fractures. Micro-CT was used to assess fracture realignment during external skeletal fixator application and to evaluate fracture healing. CONCLUSIONS AND CLINICAL RELEVANCE The prognosis for rabbits with limb fractures was good, with fractures healing in most rabbits following fracture repair (109/123). Micro-CT was useful in assessing fracture realignment and evaluating fracture healing.

Rib fracture as a predictor of future fractures in young and older postmenopausal women: National Osteoporosis Risk Assessment (NORA)

PubMed Central

Sajjan, S. G.; Barrett-Connor, E.; McHorney, C. A.; Miller, P. D.; Sen, S. S.; Siris, E.

2013-01-01

Summary A rib fracture history after age 45 was associated with a 5.4-fold increase in new rib fracture risk and a 2.4-fold increase in risk of any new clinical fracture in 155,031 postmenopausal women. A rib fracture history suggests osteoporosis and should be considered when evaluating patients for interventions to prevent fractures. Introduction Until recently, little attention was paid to rib fracture as an osteoporosis marker. Emerging evidence suggests rib fracture may be an osteoporotic fracture in men and women. We report the 5-year independent association between baseline rib fracture histories and self-reported future fractures by age (decade) in the NORA cohort (155,031 postmenopausal women, 50–99 years). Methods Participants reported fracture history and responded to follow-up surveys at years 1, 3, or 6. Women with a baseline rib fracture history without other fractures were compared with women with no fracture. Results At baseline, 4,758 (3.07%) women reported a rib fracture history without other fractures; 6,300 women reported 6,830 new clinical fractures, including wrist (2,271), rib (1,891), spine (1,136), hip (941), and forearm (591). Adjusted relative risk (ARR) values (95% confidence interval [CI]) for future fractures in women with rib fracture history versus women with no fracture history were 5.4 (4.8–6.1) at the rib, 2.1 (1.7–2.6) at the spine, and 1.4 (1.1–1.7) at the wrist, and not significant for forearm or hip fractures. Future fracture risk was at least doubled in women with a rib fracture history in all ages: ARR (95% CI) 3.4 (2.8–4.0) for ages 50–59, 2.5 (2.1–3.0) for ages 60–69, 2.0 (1.7–2.3) for ages 70–79, and 2.0 (1.6–2.6) for ages >80. Conclusions Rib fracture, the second most common clinical fracture in women (after wrist fracture), predicted future fractures of the rib, wrist, and spine at all ages. Women presenting with rib fractures should be evaluated for appropriate management to prevent future fractures. PMID:21904951

High fracture probability predicts fractures in a 4-year follow-up in women from the RAC-OST-POL study.

PubMed

Pluskiewicz, W; Adamczyk, P; Czekajło, A; Grzeszczak, W; Drozdzowska, B

2015-12-01

In 770 postmenopausal women, the fracture incidence during a 4-year follow-up was analyzed in relation to the fracture probability (FRAX risk assessment tool) and risk (Garvan risk calculator) predicted at baseline. Incident fractures occurred in 62 subjects with a higher prevalence in high-risk subgroups. Prior fracture, rheumatoid arthritis, femoral neck T-score and falls increased independent of fracture incidence. The aim of the study was to analyze the incidence of fractures during a 4-year follow-up in relation to the baseline fracture probability and risk. Enrolled in the study were 770 postmenopausal women with a mean age of 65.7 ± 7.3 years. Bone mineral density (BMD) at the proximal femur, clinical data, and fracture probability using the FRAX tool and risk using the Garvan calculator were determined. Each subject was asked yearly by phone call about the incidence of fracture during the follow-up period. Of the 770 women, 62 had a fracture during follow-up, and 46 had a major fracture. At baseline, BMD was significantly lower, and fracture probability and fracture risk were significantly higher in women who had a fracture. Among women with a major fracture, the percentage with a high baseline fracture probability (>10 %) was significantly higher than among those without a fracture (p < 0.01). Fracture incidence during follow-up was significantly higher among women with a high baseline fracture probability (12.7 % vs. 5.2 %) and a high fracture risk (9.2 vs. 5.3 %) so that the "fracture-free survival" curves were significantly different (p < 0.05). The number of clinical risk factors noted at baseline was significantly associated with fracture incidence (chi-squared = 20.82, p < 0.01). Prior fracture, rheumatoid arthritis, and femoral neck T-score were identified as significant risk factors for major fractures (for any fractures, the influence of falls was also significant). During follow-up, fracture incidence was predicted by baseline fracture probability (FRAX risk assessment tool) and risk (Garvan risk calculator). A number of clinical risk factors and a prior fracture, rheumatoid arthritis, femoral neck T-score, and falls were independently associated with an increased incidence of fractures. [Corrected

Spontaneous acute spinal subdural hematoma: spontaneous recovery from severe paraparesis--case report and review.

PubMed

Payer, Michael; Agosti, Reto

2010-11-01

Spontaneous idiopathic acute spinal subdural hematomas are highly exceptional. Neurological symptoms are usually severe, and rapid diagnosis with MRI is mandatory. Surgical evacuation has frequently been used therapeutically; however, spontaneous recovery in mild cases has also been reported. We present a case of spontaneous recovery from severe paraparesis after spontaneous acute SSDH, and review the English-speaking literature.

Psychiatric symptoms and pregnancy distress in subsequent pregnancy after spontaneous abortion history.

PubMed

Haghparast, Elahe; Faramarzi, Mahbobeh; Hassanzadeh, Ramezan

2016-01-01

Spontaneous abortion is one of the most important complications of pregnancy with short and long adverse psychological effects on women. This study assesses the implications of a spontaneous abortion history has on women's psychiatric symptoms and pregnancy distress in subsequent pregnancy less than one years after spontaneous abortion. A case-control study was conducted on pregnant women of Babol city from September 2014 to May 2015. In this study, 100 pregnant women with spontaneous abortion history during a year ago and 100 pregnant women without spontaneous abortion history were enrolled. All the participants in two groups completed the Symptom Checklist-90-Revised (SCL-90-R), and pregnancy Distress Questionnaire (PDQ). Women with spontaneous abortion history had significantly higher mean of many subscales of SCL-90 (depression, anxiety, somatization, obsessive-compulsiveness, interpersonal sensitivity, psychoticism, hostility, paranoid, and Global Severity Index) more than women without spontaneous abortion history. Also, women with spontaneous abortion history had significantly higher mean of two subscales of PDQ concerns about birth and the baby, concerns about emotions and relationships) and total PDQ more than women without spontaneous abortion history. Pregnant women with less than a year after spontaneous abortion history are at risk of psychiatric symptoms and pregnancy distress more than controls. This study supports those implications for planning the post spontaneous abortion psychological care for women, especially women who wanted to be pregnant during 12 month after spontaneous abortion.

Measurements of radiated elastic wave energy from dynamic tensile cracks

NASA Technical Reports Server (NTRS)

Boler, Frances M.

1990-01-01

The role of fracture-velocity, microstructure, and fracture-energy barriers in elastic wave radiation during a dynamic fracture was investigated in experiments in which dynamic tensile cracks of two fracture cofigurations of double cantilever beam geometry were propagating in glass samples. The first, referred to as primary fracture, consisted of fractures of intact glass specimens; the second configuration, referred to as secondary fracture, consisted of a refracture of primary fracture specimens which were rebonded with an intermittent pattern of adhesive to produce variations in fracture surface energy along the crack path. For primary fracture cases, measurable elastic waves were generated in 31 percent of the 16 fracture events observed; the condition for radiation of measurable waves appears to be a local abrupt change in the fracture path direction, such as occurs when the fracture intersects a surface flaw. For secondary fractures, 100 percent of events showed measurable elastic waves; in these fractures, the ratio of radiated elastic wave energy in the measured component to fracture surface energy was 10 times greater than for primary fracture.

Periprosthetic fractures of the humerus.

PubMed

McDonough, Edward B; Crosby, Lynn A

2005-12-01

Periprosthetic humeral fractures present a treatment challenge for the orthopedic surgeon. The overall incidence of fracture is between 0.5% and 3%, with the majority of fractures occurring intraoperatively and involving the humeral diaphysis. Excess torque produced during surgery is usually responsible for intraoperative fractures. Improper canal preparation or prosthetic placement may also increase the chance of sustaining a fracture. Postoperative fractures are most commonly caused by minor trauma, such as a fall. Poor bone quality, female sex, advanced age, and history of rheumatoid arthritis are the risk factors most commonly associated with periprosthetic fractures. All 4 systems used to describe periprosthetic humeral shaft fractures classify fracture patterns according to the anatomic relation of the fracture to the prosthetic stem. Treatment decisions should be made with respect to obtaining fracture stability, initiating early gleno-humeral motion, and restoring shoulder function. Intraoperative fractures and any postoperative fracture resulting in prosthetic instability should be treated with a long-stem prosthesis extending at least 2 to 3 cortical diameters past the fracture site with consideration for rigid plate fixation. Short oblique or transverse postoperative fractures should be managed with early stable fixation. There has been some support for conservative treatment of long oblique or spiral postoperative fractures. Postoperative diaphyseal fractures distal to the stem generally are well maintained with standard fracture management.

Clavicle fractures: epidemiology, classification and treatment of 2 422 fractures in the Swedish Fracture Register; an observational study.

PubMed

Kihlström, Caroline; Möller, Michael; Lönn, Katarina; Wolf, Olof

2017-02-15

Large multi-centre studies of clavicle fractures have so far been missing. The aim of this observational study was to describe the epidemiology, classification and treatment of clavicle fractures in the The Swedish Fracture Register (SFR) that collects national prospective data from large fracture populations. Data were retrieved from the SFR on all clavicle fractures sustained by patients ≥ 15 years of age in 2013-2014 (n = 2 422) with regards to date of injury, cause of injury, fracture classification and treatment. Sixty-eight per cent of the clavicle fractures occurred in males. The largest subgroup was males aged 15-24 years, representing 21% of clavicle fractures. At the ages of 65 years and above, females sustained more clavicle fractures than males. Same-level falls and bicycle accidents were the most common injury mechanisms. Displaced midshaft fractures constituted 43% of all fractures and were the most frequently operated fractures. Seventeen per cent of the patients underwent operative treatment within 30 days of the injury, where plate fixation was the choice of treatment in 94% of fractures. The largest patient group was young males. Displaced midshaft fractures were the most common type of clavicle fracture as well as the most frequently operated type of fracture.

Visually Evoked Spiking Evolves While Spontaneous Ongoing Dynamics Persist

PubMed Central

Huys, Raoul; Jirsa, Viktor K.; Darokhan, Ziauddin; Valentiniene, Sonata; Roland, Per E.

2016-01-01

Neurons in the primary visual cortex spontaneously spike even when there are no visual stimuli. It is unknown whether the spiking evoked by visual stimuli is just a modification of the spontaneous ongoing cortical spiking dynamics or whether the spontaneous spiking state disappears and is replaced by evoked spiking. This study of laminar recordings of spontaneous spiking and visually evoked spiking of neurons in the ferret primary visual cortex shows that the spiking dynamics does not change: the spontaneous spiking as well as evoked spiking is controlled by a stable and persisting fixed point attractor. Its existence guarantees that evoked spiking return to the spontaneous state. However, the spontaneous ongoing spiking state and the visual evoked spiking states are qualitatively different and are separated by a threshold (separatrix). The functional advantage of this organization is that it avoids the need for a system reorganization following visual stimulation, and impedes the transition of spontaneous spiking to evoked spiking and the propagation of spontaneous spiking from layer 4 to layers 2–3. PMID:26778982

Prevalence of Temporal Bone Fractures in Patients with Mandibular Fractures Using Multidetector-Row CT.

PubMed

Ogura, I; Kaneda, T; Sasaki, Y; Buch, K; Sakai, O

2015-06-01

Temporal bone fracture after mandibular trauma is thought to be rare, and its prevalence has not been reported in the literature. The purpose of this study was to investigate the prevalence of temporal bone fractures in patients with mandibular fractures and the relationship between temporal bone fractures and the mandibular fracture location using multidetector-row computed tomography (MDCT). A prospective study was performed in 201 patients with mandibular fractures who underwent 64-MDCT scans. The mandibular fracture locations were classified as median, paramedian, angle, and condylar types. Statistical analysis for the relationship between prevalence of temporal bone fractures and mandibular fracture locations was performed using χ(2) test with Fisher's exact test. A P-value < 0.05 was considered statistically significant. The percentage of cases with temporal bone fracture was 3.0 % of all patients with mandibular fractures and 19.0 % of those with multiple mandibular fractures of paramedian and condylar type. There was a significant relationship between the incidence of temporal bone fracture and the paramedian- and condylar-type mandibular fracture (P = 0.001). Multiple mandibular fractures of paramedian and condylar type may be a stronger indicator for temporal bone fractures. This study suggests that patients with mandibular fracture, especially the paramedian and condylar type, should be examined for coexisting temporal bone fracture using MDCT.

Deformed Materials: Towards a Theory of Materials Morphology Dynamics

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

Sethna, James P

This grant supported work on the response of crystals to external stress. Our primary work described how disordered structural materials break in two (statistical models of fracture in disordered materials), studied models of deformation bursts (avalanches) that mediate deformation on the microscale, and developed continuum dislocation dynamics models for plastic deformation (as when scooping ice cream bends a spoon, Fig. 9). Glass is brittle -- it breaks with almost atomically smooth fracture surfaces. Many metals are ductile -- when they break, the fracture surface is locally sheared and stretched, and it is this damage that makes them hard to break.more » Bone and seashells are made of brittle material, but they are strong because they are disordered -- lots of little cracks form as they are sheared and near the fracture surface, diluting the external force. We have studied materials like bone and seashells using simulations, mathematical tools, and statistical mechanics models from physics. In particular, we studied the extreme values of fracture strengths (how likely will a beam in a bridge break far below its design strength), and found that the traditional engineering tools could be improved greatly. We also studied fascinating crackling-noise precursors -- systems which formed microcracks of a broad range of sizes before they broke. Ductile metals under stress undergo irreversible plastic deformation -- the planes of atoms must slide across one another (through the motion of dislocations) to change the overall shape in response to the external force. Microscopically, the dislocations in crystals move in bursts of a broad range of sizes (termed 'avalanches' in the statistical mechanics community, whose motion is deemed 'crackling noise'). In this grant period, we resolved a longstanding mystery about the average shape of avalanches of fixed duration (using tools related to an emergent scale invariance), we developed the fundamental theory describing the shapes of avalanches and how they are affected by the edges of the microscope viewing window, we found that slow creep of dislocations can trigger an oscillating response explaining recent experiments, we explained avalanches under external voltage, and we have studied how avalanches in experiments on the microscale relate to deformation of large samples. Inside the crystals forming the metal, the dislocations arrange into mysterious cellular structures, usually ignored in theories of plasticity. Writing a natural continuum theory for dislocation dynamics, we found that it spontaneously formed walls -- much like models of traffic jams and sonic booms. These walls formed rather realistic cellular structures, which we examined in great detail -- our walls formed fractal structures with fascinating scaling properties, related to those found in turbulent fluids. We found, however, that the numerical and mathematical tools available to solve our equations were not flexible enough to incorporate materials-specific information, and our models did not show the dislocation avalanches seen experimentally. In the last year of this grant, we wrote an invited review article, explaining how plastic flow in metals shares features with other stressed materials, and how tools of statistical physics used in these other systems might be crucial for understanding plasticity.« less

Treatment of Pediatric Condylar Fractures: A 20-Year Experience.

PubMed

Ghasemzadeh, Ali; Mundinger, Gerhard S; Swanson, Edward W; Utria, Alan F; Dorafshar, Amir H

2015-12-01

The purpose of this study was to define patterns of injury and treatment for condylar and subcondylar fractures and evaluate short-term outcomes in the pediatric population. A retrospective chart review was performed on pediatric patients with mandibular condylar fractures who presented between 1990 and 2010. Computed tomographic imaging was reviewed for all patients to assess fracture characteristics. Mandibular fractures were codified using the Strasbourg Osteosynthesis Research Group and Lindahl classification methods. Sixty-four patients with 92 condylar fractures were identified. Of these patients, 29 had isolated condylar fracture and 35 had a condylar fracture associated with an additional mandibular arch fracture. The most common fracture patterns were diacapitular fracture in the Strasbourg Osteosynthesis Research Group system (n = 46) and vertical condylar head fracture in the Lindahl system (n = 14). Condylar fracture with additional mandibular arch fractures were treated with maxillomandibular fixation more often than patients with condylar fracture [n = 40 (74.1 percent) versus n = 14 (25.9 percent); p = 0.004]. No condylar fracture was treated in an open fashion. Forty-three patients returned for follow-up. The median follow-up period was 81 days (interquartile range, 35 to 294 days). Ten patients had complications (23.3 percent). The most common complication was malocclusion (n = 5). Nine of 10 patients with complications had condylar fracture with an additional mandibular arch fracture. Closed treatment of condylar fractures yields satisfactory results in pediatric patients. Pediatric patients with condylar fractures combined with additional arch fractures experience a higher rate of unfavorable outcomes.

Mandibular fracture patterns consistent with posterior maxillary fractures involving the posterior maxillary sinus, pterygoid plate or both: CT characteristics.

PubMed

Imai, T; Sukegawa, S; Kanno, T; Fujita, G; Yamamoto, N; Furuki, Y; Michizawa, M

2014-01-01

The aim of this study was to determine the incidence of posterior maxillary fractures involving the posterior maxillary sinus wall, pterygoid plate or both, unrelated to major midface fractures in patients with mandibular fractures, and to characterize associated fractures. A CT study was performed in patients with mandibular fractures to identify posterior maxillary fractures. Patients aged under 16 years, those with mandibular fractures involving only dentoalveolar components and those with concurrent major midfacial fractures were excluded. 13 (6.7%) of 194 patients with mandibular fractures also had posterior maxillary fractures (case group). The injury pattern correlated with the external force directed to the lateral side of the mandible (p < 0.001), alcohol consumption (p = 0.049), the presence of multifocal fractures (p = 0.002) and the fracture regions in the symphysis/parasymphysis (p = 0.001) and the angle/ramus (p = 0.001). No significant difference between the case and non-case groups was seen for age, sex or cause of trauma. Non-displaced fractures in the ipsilateral posterior mandible occurred with significant frequency (p = 0.001) when the posterior maxillary fractures involved only the sinus. Mandibular fractures accompanied by posterior maxillary fractures are not rare. The finding of a unilateral posterior maxillary fracture on CT may aid the efficient radiological examination of the mandible based on possible patterns of associated fractures, as follows: in the ipsilateral posterior region as a direct fracture when the impact is a medially directed force, and in the symphysis/parasymphysis or contralateral condylar neck as an indirect fracture.

Ankle fracture spur sign is pathognomonic for a variant ankle fracture.

PubMed

Hinds, Richard M; Garner, Matthew R; Lazaro, Lionel E; Warner, Stephen J; Loftus, Michael L; Birnbaum, Jacqueline F; Burket, Jayme C; Lorich, Dean G

2015-02-01

The hyperplantarflexion variant ankle fracture is composed of a posterior tibial lip fracture with posterolateral and posteromedial fracture fragments separated by a vertical fracture line. This infrequently reported injury pattern often includes an associated "spur sign" or double cortical density at the inferomedial tibial metaphysis. The objective of this study was to quantitatively establish the association of the ankle fracture spur sign with the hyperplantarflexion variant ankle fracture. Our clinical database of operative ankle fractures was retrospectively reviewed for the incidence of hyperplantarflexion variant and nonvariant ankle fractures as determined by assessment of injury radiographs, preoperative advanced imaging, and intraoperative observation. Injury radiographs were then evaluated for the presence of the spur sign, and association between the spur sign and variant fractures was analyzed. The incidence of the hyperplantarflexion variant fracture among all ankle fractures was 6.7% (43/640). The spur sign was present in 79% (34/43) of variant fractures and absent in all nonvariant fractures, conferring a specificity of 100% in identifying variant fractures. Positive predictive value and negative predictive value were 100% and 99%, respectively. The ankle fracture spur sign was pathognomonic for the hyperplantarflexion variant ankle fracture. It is important to identify variant fractures preoperatively as patient positioning, operative approach, and fixation construct of variant fractures often differ from those employed for osteosynthesis of nonvariant fractures. Identification of the spur sign should prompt acquisition of advanced imaging to formulate an appropriate operative plan to address the variant fracture pattern. Level III, retrospective comparative study. © The Author(s) 2014.

Association of Ipsilateral Rib Fractures With Displacement of Midshaft Clavicle Fractures.

PubMed

Stahl, Daniel; Ellington, Matthew; Brennan, Kindyle; Brennan, Michael

2017-04-01

To determine whether the presence of ipsilateral rib fractures affects the rate of a clavicle fracture being unstable (>100% displacement). A retrospective review from 2002-2013 performed at a single level 1 trauma center evaluated 243 midshaft clavicle fractures. Single Level 1 trauma center. These fractures were subdivided into those with ipsilateral rib fractures (CIR; n = 149) and those without ipsilateral rib fractures (CnIR; n = 94). The amount of displacement was measured on the initial injury radiograph and subsequent follow-up radiographs. Fractures were classified into either <100% displacement or >100% displacement, based on anteroposterior radiographs. Ipsilateral rib fractures were recorded based on which number rib was fractured and the total number of fractured ribs. One hundred sixteen (78%) of the CIR group and 51 (54%) of the CnIR group were found to have >100% displacement at follow-up (P = 0.0047). Seventy-two percent of the CIR group demonstrated progression from <100% to >100% displacement of the fracture compared with only 54% of the CnIR group (P < 0.05). The odds ratio for progression of the clavicle fracture to >100% was 4.08 (P = 0.000194) when ribs 1-4 were fractured and not significant for rib fractures 5-8 or 9-12. The presence of concomitant ipsilateral rib fractures significantly increases the rate of midshaft clavicle fractures being >100% displaced. In addition, a fracture involving the upper one-third of the ribs significantly increases the rate of the clavicle fracture being >100% displaced on early follow-up. Clavicle fractures with associated ipsilateral rib fractures tend to demonstrate an increased amount of displacement on follow-up radiographs compared with those without ipsilateral rib fractures. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Progressively increasing fracture risk with advancing age after initial incident fragility fracture: the Tromsø study.

PubMed

Ahmed, Luai Awad; Center, Jacqueline R; Bjørnerem, Ashild; Bluic, Dana; Joakimsen, Ragnar M; Jørgensen, Lone; Meyer, Haakon E; Nguyen, Nguyen D; Nguyen, Tuan V; Omsland, Tone K; Størmer, Jan; Tell, Grethe S; van Geel, Tineke Acm; Eisman, John A; Emaus, Nina

2013-10-01

The risk of subsequent fracture is increased after initial fractures; however, proper understanding of its magnitude is lacking. This population-based study examines the subsequent fracture risk in women and men by age and type of initial incident fracture. All incident nonvertebral fractures between 1994 and 2009 were registered in 27,158 participants in the Tromsø Study, Norway. The analysis included 3108 subjects with an initial incident fracture after the age of 49 years. Subsequent fracture (n = 664) risk was expressed as rate ratios (RR) and absolute proportions irrespective of death. The rates of both initial and subsequent fractures increased with age, the latter with the steepest curve. Compared with initial incident fracture rate of 30.8 per 1000 in women and 12.9 per 1000 in men, the overall age-adjusted RR of subsequent fracture was 1.3 (95% CI, 1.2-1.5) in women, and 2.0 (95% CI, 1.6-2.4) in men. Although the RRs decreased with age, the absolute proportions of those with initial fracture who suffered a subsequent fracture increased with age; from 9% to 30% in women and from 10% to 26% in men, between the age groups 50-59 to 80+ years. The type of subsequent fracture varied by age from mostly minor fractures in the youngest to hip or other major fractures in the oldest age groups, irrespective of type and severity of initial fracture. In women and men, 45% and 38% of the subsequent hip or other major fractures, respectively, were preceded by initial minor fractures. The risk of subsequent fracture is high in all age groups. At older age, severe subsequent fracture types follow both clinically severe and minor initial incident fractures. Any fragility fracture in the elderly reflects the need for specific osteoporosis management to reduce further fracture risk. © 2013 American Society for Bone and Mineral Research.

Fracture Reactivation in Chemically Reactive Rock Systems

NASA Astrophysics Data System (ADS)

Eichhubl, P.; Hooker, J. N.

2013-12-01

Reactivation of existing fractures is a fundamental process of brittle failure that controls the nucleation of earthquake ruptures, propagation and linkage of hydraulic fractures in oil and gas production, and the evolution of fault and fracture networks and thus of fluid and heat transport in the upper crust. At depths below 2-3 km, and frequently shallower, brittle processes of fracture growth, linkage, and reactivation compete with chemical processes of fracture sealing by mineral precipitation, with precipitation rates similar to fracture opening rates. We recently found rates of fracture opening in tectonically quiescent settings of 10-20 μm/m.y., rates similar to euhedral quartz precipitation under these conditions. The tendency of existing partially or completely cemented fractures to reactivate will vary depending on strain rate, mineral precipitation kinetics, strength contrast between host rock and fracture cement, stress conditions, degree of fracture infill, and fracture network geometry. Natural fractures in quartzite of the Cambrian Eriboll Formation, NW Scotland, exhibit a complex history of fracture formation and reactivation, with reactivation involving both repeated crack-seal opening-mode failure and shear failure of fractures that formed in opening mode. Fractures are partially to completely sealed with crack-seal or euhedral quartz cement or quartz cement fragmented by shear reactivation. Degree of cementation controls the tendency of fractures for later shear reactivation, to interact elastically with adjacent open fractures, and their intersection behavior. Using kinematic, dynamic, and diagenetic criteria, we determine the sequence of opening-mode fracture formation and later shear reactivation. We find that sheared fracture systems of similar orientation display spatially varying sense of slip We attribute these inconsistent directions of shear reactivation to 1) a heterogeneous stress field in this highly fractured rock unit and 2) variations in the degree of fracture cement infill in fractures of same orientation, allowing fractures to reactivate at times when adjacent, more cemented fractures remain dormant. The observed interaction of chemical and mechanical fracture growth and sealing processes in this chemically reactive and heavily deformed rock unit results in a complex fracture network geometry not generally observed in less chemically reactive, shallower crustal environments.

Rigid fixation of facial fractures in children.

PubMed

Koltai, P J; Rabkin, D; Hoehn, J

1995-01-01

This article presents a retrospective analysis of a selective use of rigid fixation among 62 children with facial fractures, treated at a Level I trauma center over a 5-year period (1986-1991). There were 21 mandible fractures, 11 orbital fractures, 11 zygomaticomalar complex fractures, 7 nasal fractures, 5 maxillary fractures, 3 pan-facial fractures, 2 nasal-orbital-ethmoidal complex fractures, and 2 frontal sinus fractures. Only 18 children had rigid fixation of their injuries. Complications of Le Fort upper facial fractures repaired with rigid fixation involved perioperative sinusitis; one case required oral antibiotics, the other ethmoidectomy and maxillary antrostomy. One child with a Le Fort fracture had delayed exposure of a zygomaticomalar buttress plate, which required surgical removal. Permanent enophthalmos occurred in two children with Le Fort fractures. The authors conclude that traditional conservative management is appropriate in most cases. However, in children aged 13 and older with mandible fractures and children with complex mid- and upper facial fractures, a judicious use of rigid fixation has advantages over the traditional techniques.

A new classification and treatment protocol for combined fractures of the femoral shaft with the proximal or distal femur with closed locked intramedullary nailing: clinical experience of 63 fractures.

PubMed

Lambiris, Elias; Giannikas, Dimitrios; Galanopoulos, George; Tyllianakis, Minos; Megas, Panagiotis

2003-03-01

The medical records and radiographs of 63 patients, who were admitted between 1989-1997, with a combined femur fracture, were reviewed. Associated injuries were present in 38 (60%) patients. The combined fractures were classified into four major types depending on their anatomical position: type I, femoral shaft fracture combined with hip neck fracture; type II, femoral shaft fracture combined with a trochanteric fracture; type III, femoral shaft fracture combined with a distal femur fracture; and type IV, femoral shaft fracture combined with a proximal or distal femur fracture. The fractures were treated with locked intramedullary nailing and additional free cancellous 6.5-mm screws as needed. Fifty-six fractures healed without further operations. Of the remaining 6 fractures, 2 were material failures, 1 malunion with 3-cm shortening and external rotation of the femoral diaphysis, 2 early infections of the surgical wound, and 1 pseudarthrosis of the femoral shaft. All fractures were healed between 16 and 32 weeks (average: 20 weeks).

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

Investigation of Three Approaches to Address Fear of Recurrence Among Breast Cancer Survivors

ClinicalTrials.gov

2017-08-16

Breast Neoplasms; Breast Cancer; Breast Carcinoma; Malignant Neoplasm of Breast; Cancer of Breast; Mammary Neoplasm, Human; Human Mammary Carcinoma; Malignant Tumor of Breast; Mammary Cancer; Mammary Carcinoma; Anxiety; Fear; Neoplasm Remission, Spontaneous; Spontaneous Neoplasm Regression; Regression, Spontaneous Neoplasm; Remission, Spontaneous Neoplasm; Spontaneous Neoplasm Remission

Cholesterol blocks spontaneous insertion of membrane proteins into liposomes of phosphatidylcholine.

PubMed

Nakamura, Shota; Suzuki, Sonomi; Saito, Hiroaki; Nishiyama, Ken-Ichi

2018-04-01

Spontaneous insertion of membrane proteins into liposomes formed from Escherichia coli polar phospholipids is blocked by diacylglycerol (DAG) at a physiological level. We found that cholesterol also blocks this spontaneous insertion, although a much larger amount is necessary for sufficient blockage. Reversely, sphingomyelin enhanced the spontaneous insertion. DAG at a physiological level was found not to block spontaneous insertion into liposomes formed from phosphatidylcholine (PC), while non-physiologically high concentrations of DAG reduced it. On the other hand, cholesterol blocked the spontaneous insertion into PC liposomes at a physiological level, explaining that both PC and cholesterol are absent in E. coli. While sphingomyelin did not enhance spontaneous insertion into PC liposomes, the effect of cholesterol on blockage of spontaneous insertion was dominant over that of sphingomyelin, suggesting that cholesterol functions as a blocker of disordered spontaneous insertion in eukaryotic cells. Lower amount of cholesterol was necessary to block spontaneous insertion into ER-mimic liposomes, explaining that ER membranes contain less amount of cholesterol. These results also explain that cholesterol, but not DAG, is involved in blockage of spontaneous insertion in eukaryotic cells, since DAG plays an important role as a second messenger in signal transduction.

Psychiatric symptoms and pregnancy distress in subsequent pregnancy after spontaneous abortion history

PubMed Central

Haghparast, Elahe; Faramarzi, Mahbobeh; Hassanzadeh, Ramezan

2016-01-01

Objectives: Spontaneous abortion is one of the most important complications of pregnancy with short and long adverse psychological effects on women. This study assesses the implications of a spontaneous abortion history has on women’s psychiatric symptoms and pregnancy distress in subsequent pregnancy less than one years after spontaneous abortion. Methods: A case-control study was conducted on pregnant women of Babol city from September 2014 to May 2015. In this study, 100 pregnant women with spontaneous abortion history during a year ago and 100 pregnant women without spontaneous abortion history were enrolled. All the participants in two groups completed the Symptom Checklist-90-Revised (SCL-90-R), and pregnancy Distress Questionnaire (PDQ). Results: Women with spontaneous abortion history had significantly higher mean of many subscales of SCL-90 (depression, anxiety, somatization, obsessive-compulsiveness, interpersonal sensitivity, psychoticism, hostility, paranoid, and Global Severity Index) more than women without spontaneous abortion history. Also, women with spontaneous abortion history had significantly higher mean of two subscales of PDQ concerns about birth and the baby, concerns about emotions and relationships) and total PDQ more than women without spontaneous abortion history. Conclusion: Pregnant women with less than a year after spontaneous abortion history are at risk of psychiatric symptoms and pregnancy distress more than controls. This study supports those implications for planning the post spontaneous abortion psychological care for women, especially women who wanted to be pregnant during 12 month after spontaneous abortion. PMID:27882001

Physical simulation study on the hydraulic fracture propagation of coalbed methane well

NASA Astrophysics Data System (ADS)

Wu, Caifang; Zhang, Xiaoyang; Wang, Meng; Zhou, Longgang; Jiang, Wei

2018-03-01

As the most widely used technique to modify reservoirs in the exploitation of unconventional natural gas, hydraulic fracturing could effectively raise the production of CBM wells. To study the propagation rules of hydraulic fractures, analyze the fracture morphology, and obtain the controlling factors, a physical simulation experiment was conducted with a tri-axial hydraulic fracturing test system. In this experiment, the fracturing sample - including the roof, the floor, and the surrounding rock - was prepared from coal and similar materials, and the whole fracturing process was monitored by an acoustic emission instrument. The results demonstrated that the number of hydraulic fractures in coal is considerably higher than that observed in other parts, and the fracture morphology was complex. Vertical fractures were interwoven with horizontal fractures, forming a connected network. With the injection of fracturing fluid, a new hydraulic fracture was produced and it extended along the preexisting fractures. The fracture propagation was a discontinuous, dynamic process. Furthermore, in-situ stress plays a key role in fracture propagation, causing the fractures to extend in a direction perpendicular to the minimum principal stress. To a certain extent, the different mechanical properties of the coal and the other components inhibited the vertical propagation of hydraulic fractures. Nonetheless, the vertical stress and the interfacial property are the major factors to influence the formation of the "T" shaped and "工" shaped fractures.

High prevalence of simultaneous rib and vertebral fractures in patients with hip fracture.

PubMed

Lee, Bong-Gun; Sung, Yoon-Kyoung; Kim, Dam; Choi, Yun Young; Kim, Hunchul; Kim, Yeesuk

2017-02-01

The purpose was to evaluate the prevalence and location of simultaneous fracture using bone scans in patients with hip fracture and to determine the risk factors associated with simultaneous fracture. One hundred eighty two patients with hip fracture were reviewed for this study. Clinical parameters and bone mineral density (BMD) of the lumbar vertebra and femoral neck were investigated. To identify acute simultaneous fracture, a bone scan was performed at 15.4±4.1days after hip fracture. The prevalence and location of simultaneous fracture were evaluated, and multivariate logistic regression analysis was performed to determine the risk factors. Simultaneous fracture was observed in 102 of 182 patients, a prevalence of 56.0%. Rib fracture was the most common type of simultaneous fracture followed by rib with vertebral fracture. The BMD of the lumbar vertebra was significantly lower in patients with simultaneous fracture (p=0.044) and was identified as an independent risk factor (odds ratio: OR 0.05, 95% confidence interval: CI 0.01-0.57). The prevalence of simultaneous fracture was relatively high among patients with hip fracture, and BMD was significantly lower in patients with simultaneous fracture than in patients without it. Surgeons should be aware of the possibility of simultaneous fracture in patients with hip fracture. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of Pediatric Condylar Fractures: A 20-Year Experience

PubMed Central

Ghasemzadeh, Ali; Mundinger, Gerhard S.; Swanson, Edward W.; Utria, Alan F.; Dorafshar, Amir H.

2016-01-01

Background The purpose of this study was to define patterns of injury and treatment for condylar and subcondylar fractures and evaluate short-term outcomes in the pediatric population. Methods A retrospective chart review was performed on pediatric patients with mandibular condylar fractures who presented between 1990 and 2010. Computed tomographic imaging was reviewed for all patients to assess fracture characteristics. Mandibular fractures were codified using the Strasbourg Osteosynthesis Research Group and Lindahl classification methods. Results Sixty-four patients with 92 condylar fractures were identified. Of these patients, 29 had isolated condylar fracture and 35 had a condylar fracture associated with an additional mandibular arch fracture. The most common fracture patterns were diacapitular fracture in the Strasbourg Osteosynthesis Research Group system (n = 46) and vertical condylar head fracture in the Lindahl system (n = 14). Condylar fracture with additional mandibular arch fractures were treated with maxillomandibular fixation more often than patients with condylar fracture [n = 40 (74.1 percent) versus n = 14 (25.9 percent); p = 0.004]. No condylar fracture was treated in an open fashion. Forty-three patients returned for follow-up. The median follow-up period was 81 days (interquartile range, 35 to 294 days). Ten patients had complications (23.3 percent). The most common complication was malocclusion (n = 5). Nine of 10 patients with complications had condylar fracture with an additional mandibular arch fracture. Conclusions Closed treatment of condylar fractures yields satisfactory results in pediatric patients. Pediatric patients with condylar fractures combined with additional arch fractures experience a higher rate of unfavorable outcomes. PMID:26595021

Mandibular fracture patterns consistent with posterior maxillary fractures involving the posterior maxillary sinus, pterygoid plate or both: CT characteristics

PubMed Central

Sukegawa, S; Kanno, T; Fujita, G; Yamamoto, N; Furuki, Y; Michizawa, M

2014-01-01

Objectives: The aim of this study was to determine the incidence of posterior maxillary fractures involving the posterior maxillary sinus wall, pterygoid plate or both, unrelated to major midface fractures in patients with mandibular fractures, and to characterize associated fractures. Methods: A CT study was performed in patients with mandibular fractures to identify posterior maxillary fractures. Patients aged under 16 years, those with mandibular fractures involving only dentoalveolar components and those with concurrent major midfacial fractures were excluded. Results: 13 (6.7%) of 194 patients with mandibular fractures also had posterior maxillary fractures (case group). The injury pattern correlated with the external force directed to the lateral side of the mandible (p < 0.001), alcohol consumption (p = 0.049), the presence of multifocal fractures (p = 0.002) and the fracture regions in the symphysis/parasymphysis (p = 0.001) and the angle/ramus (p = 0.001). No significant difference between the case and non-case groups was seen for age, sex or cause of trauma. Non-displaced fractures in the ipsilateral posterior mandible occurred with significant frequency (p = 0.001) when the posterior maxillary fractures involved only the sinus. Conclusions: Mandibular fractures accompanied by posterior maxillary fractures are not rare. The finding of a unilateral posterior maxillary fracture on CT may aid the efficient radiological examination of the mandible based on possible patterns of associated fractures, as follows: in the ipsilateral posterior region as a direct fracture when the impact is a medially directed force, and in the symphysis/parasymphysis or contralateral condylar neck as an indirect fracture. PMID:24336313

Surgery for scapula process fractures

PubMed Central

Anavian, Jack; Wijdicks, Coen A; Schroder, Lisa K; Vang, Sandy

2009-01-01

Background Generally, scapula process fractures (coracoid and acromion) have been treated nonoperatively with favorable outcome, with the exception of widely displaced fractures. Very little has been published, however, regarding the operative management of such fractures and the literature that is available involves very few patients. Our hypothesis was that operative treatment of displaced acromion and coracoid fractures is a safe and effective treatment that yields favorable surgical results. Methods We reviewed 26 consecutive patients (27 fractures) treated between 1998 and 2007. Operative indications for these process fractures included either a painful nonunion, a concomitant ipsilateral operative scapula fracture, ≥ 1 cm of displacement on X-ray, or a multiple disruption of the superior shoulder suspensory complex. All patients were followed until they were asymptomatic, displayed radiographic fracture union, and had recovered full motion with no pain. Patients and results 21 males and 5 females, mean age 36 (18–67) years, were included in the study. 18 patients had more than one indication for surgery. Of the 27 fractures, there were 13 acromion fractures and 14 coracoid fractures. 1 patient was treated for both a coracoid and an acromion fracture. Fracture patterns for the acromion included 6 acromion base fractures and 7 fractures distal to the base. Coracoid fracture patterns included 11 coracoid base fractures and 3 fractures distal to the base. Mean follow-up was 11 (2–42) months. All fractures united and all patients had recovered full motion with no pain at the time of final follow-up. 3 patients underwent removal of hardware due to irritation from hardware components that were too prominent. There were no other complications. Interpretation While most acromion and coracoid fractures can be treated nonoperatively with satisfactory results, operative management may be indicated for displaced fractures and double lesions of the superior shoulder suspensory complex. PMID:19857183

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.

Relationship between fracture of mandibular condyle and absence of unerupted mandibular third molar-a retrospective study.

PubMed

Rajan, Ritesh; Verma, Dinesh Kumar; Borle, R M; Yadav, Abhilasha

2016-06-01

The purpose of the present study was to find, if there exists, a co-relation between presence of unerupted mandibular third molar and fracture of mandibular condyle. A retrospective, multicenter study was done collecting the data of all mandibular condyle fractures treated from November 2006 till August 2015. Data was collected from the patient's records and radiographs for the following information: age, sex, etiology of fracture, presence and state of lower third molars, and associated fracture. The results were subjected to statistical analysis. Out of 180 patients of condylar fracture, unerupted third molars were present in 35 (19.44 %) cases compared to 145 (80.55 %) cases of condylar fracture where the unerupted third molars were not present. The difference was statistically significant (p < 0.05). In the unerupted third molar present group, isolated bilateral condylar fracture was seen in 4 (11.4 %) cases, bilateral condylar fracture associated with other mandibular fractures in 9 (25.7 %) cases, isolated unilateral condylar fracture in 0 (0.0 %) cases, and unilateral condylar fracture associated with other mandibular fractures in 17 (48.5 %) cases and condylar fracture associated with mid face fractures in 5 (14.2 %) cases. In the unerupted third molar absent group, isolated bilateral condylar fracture was seen in 5 (3.4 %) cases, bilateral condylar fracture associated with other mandibular fractures in 30 (20.6 %) cases, isolated unilateral condylar fracture in 24 (16.5 %) cases, unilateral condylar fracture associated with other mandibular fractures in 73 (50.34 %) cases, and condylar fracture associated with mid face fractures in 13(8.96 %) cases. The difference between the groups was statistically significant (p = 0.032). This study suggests that the fractures of mandibular condylar region have a significantly higher incidence in patients without an unerupted mandibular third molar.

Causes and treatment of mandibular and condylar fractures in children and adolescents: a review of 104 cases.

PubMed

Shi, Jun; Chen, Zhibiao; Xu, Bing

2014-03-01

There are no uniform treatments, standards, and specifications for conservative and surgical management of mandibular fractures in children and adolescents. To review the management of mandibular fractures in children and adolescents at our institution. The medical records of 104 children and adolescents (60 male and 44 female) treated for mandibular fractures from 2005 to 2012 at the Ninth People's Hospital, Shanghai, China, were retrospectively reviewed. The participants were classified as having deciduous dentition (age ≤6 years), mixed dentition (age >6 but <12 years), and permanent dentition (age ≥12 but ≤16 years). Conservative treatment and surgical management. Helkimo clinical dysfunction and anamnestic indices. Condylar process fractures accounted for 55.7% of the fractures (112 fractures of 201 total fracture sites), and symphysis fractures, parasymphysis fractures, fractures of the body, and fractures of the angle accounted for 20.9%, 11.9%, 7.0%, and 3.5% of the fractures, respectively. A total of 83 cases with 159 fracture sites with complete follow-up data were included in the treatment analysis. In these 83 patients, 77 fractures were dentigerous bone fractures, 46 were intracapsular fractures, and 36 were extracapsular fractures. Dentigerous bone fractures of the mandible were managed by closed or open reduction in children younger than 12 years and were managed more often by open reduction and fixation in those between ages 12 and 16 years. Closed treatment was performed for 22 condylar process fractures (28.6%), and open reduction was carried out for 55 condylar process fractures (71.4%). In patients with intracapsular fractures, there was no significant relationship between dentation age and treatment method (P = .06). Most patients with extracapsular fractures with permanent dentition underwent surgical fixation (73.3%), whereas most with deciduous dentition received conservative treatment (87.5%). In patients with condylar process fractures, there was no significant difference in Ai and Di based on treatment method (P = .49 and P = .76, respectively). The treatment of mandibular fractures in children and adolescents should be determined by clinical factors including age, location, and type of fracture.

Hydraulic Fracturing and Production Optimization in Eagle Ford Shale Using Coupled Geomechanics and Fluid Flow Model

NASA Astrophysics Data System (ADS)

Suppachoknirun, Theerapat; Tutuncu, Azra N.

2017-12-01

With increasing production from shale gas and tight oil reservoirs, horizontal drilling and multistage hydraulic fracturing processes have become a routine procedure in unconventional field development efforts. Natural fractures play a critical role in hydraulic fracture growth, subsequently affecting stimulated reservoir volume and the production efficiency. Moreover, the existing fractures can also contribute to the pressure-dependent fluid leak-off during the operations. Hence, a reliable identification of the discrete fracture network covering the zone of interest prior to the hydraulic fracturing design needs to be incorporated into the hydraulic fracturing and reservoir simulations for realistic representation of the in situ reservoir conditions. In this research study, an integrated 3-D fracture and fluid flow model have been developed using a new approach to simulate the fluid flow and deliver reliable production forecasting in naturally fractured and hydraulically stimulated tight reservoirs. The model was created with three key modules. A complex 3-D discrete fracture network model introduces realistic natural fracture geometry with the associated fractured reservoir characteristics. A hydraulic fracturing model is created utilizing the discrete fracture network for simulation of the hydraulic fracture and flow in the complex discrete fracture network. Finally, a reservoir model with the production grid system is used allowing the user to efficiently perform the fluid flow simulation in tight formations with complex fracture networks. The complex discrete natural fracture model, the integrated discrete fracture model for the hydraulic fracturing, the fluid flow model, and the input dataset have been validated against microseismic fracture mapping and commingled production data obtained from a well pad with three horizontal production wells located in the Eagle Ford oil window in south Texas. Two other fracturing geometries were also evaluated to optimize the cumulative production and for the three wells individually. Significant reduction in the production rate in early production times is anticipated in tight reservoirs regardless of the fracturing techniques implemented. The simulations conducted using the alternating fracturing technique led to more oil production than when zipper fracturing was used for a 20-year production period. Yet, due to the decline experienced, the differences in cumulative production get smaller, and the alternating fracturing is not practically implementable while field application of zipper fracturing technique is more practical and widely used.

Survival times of patients with a first hip fracture with and without subsequent major long-bone fractures.

PubMed

Angthong, Chayanin; Angthong, Wirana; Harnroongroj, Thos; Naito, Masatoshi; Harnroongroj, Thossart

2013-01-01

Survival rates are poorer after a second hip fracture than after a first hip fracture. Previous survival studies have included in-hospital mortality. Excluding in-hospital deaths from the analysis allows survival times to be evaluated in community-based patients. There is still a lack of data regarding the effects of subsequent fractures on survival times after hospital discharge following an initial hip fracture. This study compared the survival times of community-dwelling patients with hip fracture who had or did not have a subsequent major long-bone fracture. Hazard ratios and risk factors for subsequent fractures and mortality rates with and without subsequent fractures were calculated. Of 844 patients with hip fracture from 2000 through 2008, 71 had a subsequent major long-bone fracture and 773 did not. Patients who died of other causes, such as perioperative complications, during hospitalization were excluded. Such exclusion allowed us to determine the effect of subsequent fracture on the survival of community-dwelling individuals after hospital discharge or after the time of the fracture if they did not need hospitalization. Demographic data, causes of death, and mortality rates were recorded. Differences in mortality rates between the patient groups and hazard ratios were calculated. Mortality rates during the first year and from 1 to 5 years after the most recent fracture were 5.6% and 1.4%, respectively, in patients with subsequent fractures, and 4.7% and 1.4%, respectively, in patients without subsequent fractures. These rates did not differ significantly between the groups. Cox regression analysis and calculation of hazard ratios did not show significant differences between patients with subsequent fractures and those without. On univariate and multivariate analyses, age <75 years and male sex were risk factors for subsequent fracture. This study found that survival times did not differ significantly between patients with and without subsequent major long-bone fractures after hip fracture. Therefore, all patients with hip fracture, with or without subsequent fractures, need the same robust holistic care. The risks of subsequent fractures should be addressed in patients with hip fracture and should be reduced where possible by education regarding fracture prevention and regular rehabilitation programs. Efforts should be made to decrease the rates of major long-bone fractures and their burdens, even though such fractures have only a minor effect on survival in community-dwelling individuals.

Fracture mechanism maps in unirradiated and irradiated metals and alloys

NASA Astrophysics Data System (ADS)

Li, Meimei; Zinkle, S. J.

2007-04-01

This paper presents a methodology for computing a fracture mechanism map in two-dimensional space of tensile stress and temperature using physically-based constitutive equations. Four principal fracture mechanisms were considered: cleavage fracture, low temperature ductile fracture, transgranular creep fracture, and intergranular creep fracture. The methodology was applied to calculate fracture mechanism maps for several selected reactor materials, CuCrZr, 316 type stainless steel, F82H ferritic-martensitic steel, V4Cr4Ti and Mo. The calculated fracture maps are in good agreement with empirical maps obtained from experimental observations. The fracture mechanism maps of unirradiated metals and alloys were modified to include radiation hardening effects on cleavage fracture and high temperature helium embrittlement. Future refinement of fracture mechanism maps is discussed.

NSAIDs and spontaneous abortions – true effect or an indication bias?

PubMed Central

Daniel, Sharon; Koren, Gideon; Lunenfeld, Eitan; Levy, Amalia

2015-01-01

Aim The aim of the study was to characterize the extent of indication bias resulting from the excessive use of NSAIDs on the days preceding a spontaneous abortion to relieve pain. Methods We used data from a retrospective cohort study assessing the risk for spontaneous abortions following exposure to NSAIDs. Three definitions of exposure for cases of spontaneous abortions were compared, from the first day of pregnancy until the day of spontaneous abortion and until 3 and 2 days before a spontaneous abortion. Statistical analysis was performed using multivariate time programmed Cox regression. Results A sharp increase was observed in the dispensation of indomethacin, diclofenac and naproxen, and a milder increase was found in the use of ibuprofen during the week before a spontaneous abortion. Non- selective COX inhibitors in general and specifically diclofenac and indomethacin were found to be associated with spontaneous abortions when the exposure period was defined until the day of spontaneous abortion (hazard ratio (HR) 1.15, 95% confidence interval (CI) 1.04, 1.28; HR 1.31, 95% CI 1.08, 1.59 and HR 3.33, 95% CI 2.09, 5.29, respectively). The effect disappears by excluding exposures occurring on the day before the spontaneous abortion for non-selective COX inhibitors and on the last week before the spontaneous abortion for indomethacin. In general, decreasing HRs were found with the exclusion of exposures occurring on the days immediately before the spontaneous abortion. Conclusions The increased use of NSAIDs during the last few days that preceded a spontaneous abortion to relieve pain associated with the miscarriage could bias studies assessing the association between exposure to NSAIDs and spontaneous abortions. PMID:25858169

Amino acid and fatty acid compositions of Rusip from fermented Anchovy fish (Stolephorussp)

NASA Astrophysics Data System (ADS)

Koesoemawardani, D.; Hidayati, S.; Subeki

2018-04-01

Rusip is a typical food of Bangka Belitung Indonesia made from fermented anchovy. This study aims to determine the properties of chemistry, microbiology, composition of amino acids and fatty acids from fermented fish spontaneously and non spontaneously. Spontaneous rusip treatment is done by anchovy fish (Stolephorussp) after cleaning and added salt 25% (w/w) and palm sugar 10% (w/w). While, non-spontaneous rusip is done by adding a culture mixture of Streptococcus, Leuconostoc, and Lactobacillus bacteria 2% (w/v). The materials are then incubated for 2 weeks. The data obtained were then performed t-test at the level of 5%. Spontaneous and non-spontaneous rusip fermentation process showed significant differences in total acid, reducing sugar, salt content, TVN, total lactic acid bacteria, total mold, and total microbial. The dominant amino acid content of spontaneous and non-spontaneous rusip are glutamic acid and aspartic acid, while the dominant fatty acids in spontaneous and non-spontaneous rusip are docosahexaenoic acid, palmitic acid, oleic acid, arachidonic acid, stearic acid, eicosapentaenoic acid, palmitoleic acid, and myristic acid.

Fully Coupled 3D Finite Element Model of Hydraulic Fracturing in a Permeable Rock Formation

NASA Astrophysics Data System (ADS)

Salimzadeh, S.; Paluszny, A.; Zimmerman, R. W.

2015-12-01

Hydraulic fracturing in permeable rock formations is a complex three-dimensional multi-physics phenomenon. Numerous analytical models of hydraulic fracturing processes have been proposed that typically simplify the physical processes, or somehow reduce the problem from three dimensions to two dimensions. Moreover, although such simplified models are able to model the growth of a single hydraulic fracture into an initially intact, homogeneous rock mass, they are generally not able to model fracturing of heterogeneous rock formations, or to account for interactions between multiple induced fractures, or between an induced fracture and pre-existing natural fractures. We have developed a numerical finite-element model for hydraulic fracturing that does not suffer from any of the limitations mentioned above. The model accounts for fluid flow within a fracture, the propagation of the fracture, and the leak-off of fluid from the fracture into the host rock. Fluid flow through the permeable rock matrix is modelled using Darcy's law, and is coupled with the laminar flow within the fracture. Fractures are discretely modelled in the three-dimensional mesh. Growth of a fracture is modelled using the concepts of linear elastic fracture mechanics (LEFM), with the onset and direction of growth based on stress intensity factors that are computed for arbitrary tetrahedral meshes. The model has been verified against several analytical solutions available in the literature for plane-strain (2D) and penny-shaped (3D) fractures, for various regimes of domination: viscosity, toughness, storage and leak-off. The interaction of the hydraulically driven fracture with pre-existing fractures and other fluid-driven fractures in terms of fluid leak-off, stress interaction and fracture arrest is investigated and the results are presented. Finally, some preliminary results are presented regarding the interaction of a hydraulically-induced fracture with a set of pre-existing natural fractures.

An Embedded 3D Fracture Modeling Approach for Simulating Fracture-Dominated Fluid Flow and Heat Transfer in Geothermal Reservoirs

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

Johnston, Henry; Wang, Cong; Winterfeld, Philip

An efficient modeling approach is described for incorporating arbitrary 3D, discrete fractures, such as hydraulic fractures or faults, into modeling fracture-dominated fluid flow and heat transfer in fractured geothermal reservoirs. This technique allows 3D discrete fractures to be discretized independently from surrounding rock volume and inserted explicitly into a primary fracture/matrix grid, generated without including 3D discrete fractures in prior. An effective computational algorithm is developed to discretize these 3D discrete fractures and construct local connections between 3D fractures and fracture/matrix grid blocks of representing the surrounding rock volume. The constructed gridding information on 3D fractures is then added tomore » the primary grid. This embedded fracture modeling approach can be directly implemented into a developed geothermal reservoir simulator via the integral finite difference (IFD) method or with TOUGH2 technology This embedded fracture modeling approach is very promising and computationally efficient to handle realistic 3D discrete fractures with complicated geometries, connections, and spatial distributions. Compared with other fracture modeling approaches, it avoids cumbersome 3D unstructured, local refining procedures, and increases computational efficiency by simplifying Jacobian matrix size and sparsity, while keeps sufficient accuracy. Several numeral simulations are present to demonstrate the utility and robustness of the proposed technique. Our numerical experiments show that this approach captures all the key patterns about fluid flow and heat transfer dominated by fractures in these cases. Thus, this approach is readily available to simulation of fractured geothermal reservoirs with both artificial and natural fractures.« less

Long-bone fractures in persons with spinal cord injury.

PubMed

Frotzler, A; Cheikh-Sarraf, B; Pourtehrani, M; Krebs, J; Lippuner, K

2015-09-01

Retrospective data analysis. To document fracture characteristics, management and related complications in individuals with traumatic spinal cord injury (SCI). Rehabilitation centre for SCI individuals. Patients' records were reviewed. Patients with traumatic SCI and extremity fractures that had occurred after SCI were included. Patient characteristics, fractured bone, fracture localisation, severity and management (operative/conservative), and fracture-related complications were extracted. A total of 156 long-bone fractures in 107 SCI patients (34 women and 73 men) were identified. The majority of patients were paraplegics (77.6%) and classified as American Spinal Injury Association Impairment Scale A (86.0%). Only the lower extremities were affected, whereby the femur (60.9% of all fractures) was fractured more frequently than the lower leg (39.1%). A total of 70 patients (65.4%) had one fracture, whereas 37 patients (34.6%) had two or more fractures. Simple or extraarticular fractures were most common (75.0%). Overall, 130 (83.3%) fractures were managed operatively. Approximately half of the femur fractures (48.2%) were treated with locking compression plates. In the lower leg, fractures were mainly managed with external fixation (48.8%). Conservative fracture management was applied in 16.7% of the cases and consisted of braces or a well-padded soft cast. Fracture-associated complications were present in 13.5% of the cases but did not differ significantly between operative (13.1%) and conservative (15.4%) fracture management. SCI was associated with simple or extraarticular fractures of the distal femur and the lower leg. Fractures were mainly managed operatively with a low complication rate.

A new approach to the treatment of nasal bone fracture: radiologic classification of nasal bone fractures and its clinical application.

PubMed

Han, Daniel Seung Youl; Han, Yea Sik; Park, Jin Hyung

2011-11-01

A radiologic examination is required in the treatment of nasal bone fracture to determine the fracture condition. Thus, there is an increasing need for radiologic classification of nasal bone fractures that can be applied to clinical practice. Computed tomography was performed in 125 patients with nasal bone fractures to determine which axial view best showed the entire nasal view. The obtained axial view was then used as a reference for classification. The length from the top to the base of the nasal bone was divided into upper, middle, and lower levels, after which the fracture location was determined. If the fracture spanned the boundaries of these levels, it was classified as the total level. Subsequently, the fracture was subclassified based on the fracture direction and pattern and the concurrent fracture. Radiologic examination of patients with nasal bone fracture showed that nasal bone fracture was frequently found at the total, middle, upper, and lower levels, in that order. Nasal bone fractures at the upper level showed lower frequencies of complication and reoperation than the fractures at the other levels, whereas nasal bone fractures at the total level showed the highest frequencies of complication and reoperation. Radiologic classification can be useful for preoperative and postoperative evaluations of nasal bone fractures and can be helpful in understanding such fractures because it can efficiently predict the prognosis of a fracture. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

A Rare Entity: Bilateral First Rib Fractures Accompanying Bilateral Scapular Fractures.

PubMed

Gulbahar, Gultekin; Kaplan, Tevfik; Turker, Hasan Bozkurt; Gundogdu, Ahmet Gokhan; Han, Serdar

2015-01-01

First rib fractures are scarce due to their well-protected anatomic locations. Bilateral first rib fractures accompanying bilateral scapular fractures are very rare, although they may be together with scapular and clavicular fractures. According to our knowledge, no case of bilateral first rib fractures accompanying bilateral scapular fractures has been reported, so we herein discussed the diagnosis, treatment, and complications of bone fractures due to thoracic trauma in bias of this rare entity.

A Rare Entity: Bilateral First Rib Fractures Accompanying Bilateral Scapular Fractures

PubMed Central

Gulbahar, Gultekin; Kaplan, Tevfik; Turker, Hasan Bozkurt; Gundogdu, Ahmet Gokhan; Han, Serdar

2015-01-01

First rib fractures are scarce due to their well-protected anatomic locations. Bilateral first rib fractures accompanying bilateral scapular fractures are very rare, although they may be together with scapular and clavicular fractures. According to our knowledge, no case of bilateral first rib fractures accompanying bilateral scapular fractures has been reported, so we herein discussed the diagnosis, treatment, and complications of bone fractures due to thoracic trauma in bias of this rare entity. PMID:26175916

Laboratory investigation of shale rock to identify fracture propagation in vertical direction to bedding

NASA Astrophysics Data System (ADS)

Peng, Tan; Yan, Jin; Bing, Hou; Yingcao, Zhou; Ruxin, Zhang; Zhi, Chang; Meng, Fan

2018-06-01

Affected by beddings and natural fractures, fracture geometry in the vertical plane is complex in shale formation, which differs from a simple fracture in homogeneous sandstone reservoirs. However, the propagation mechanism of a hydraulic fracture in the vertical plane has not been well understood. In this paper, a true tri-axial pressure machine was deployed for shale horizontal well fracturing simulation experiments of shale outcrops. The effects of multiple factors on hydraulic fracture vertical propagation were studied. The results revealed that hydraulic fracture initiation and propagation displayed four basic patterns in the vertical plane of laminated shale formation. A hydraulic fracture would cross the beddings under the high vertical stress difference between a vertical stress and horizontal minimum stress of 12 MPa, while a hydraulic fracture propagates along the beddings under a low vertical stress difference of 3 MPa. Four kinds of fracture geometry, including a single main fracture, a nonplanar fracture, a complex fracture, and a complex fracture network, were observed due to the combined effects of flow rate and viscosity. Due to the influence of binding strength (or cementing strength) on the fracture communication effects between a hydraulic fracture and the beddings, the opening region of the beddings takes the shape of an ellipse.

Comparison of Surface Properties in Natural and Artificially Generated Fractures in a Crystalline Rock

NASA Astrophysics Data System (ADS)

Vogler, Daniel; Walsh, Stuart D. C.; Bayer, Peter; Amann, Florian

2017-11-01

This work studies the roughness characteristics of fracture surfaces from a crystalline rock by analyzing differences in surface roughness between fractures of various types and sizes. We compare the surface properties of natural fractures sampled in situ and artificial (i.e., man-made) fractures created in the same source rock under laboratory conditions. The topography of the various fracture types is compared and characterized using a range of different measures of surface roughness. Both natural and artificial, and tensile and shear fractures are considered, along with the effects of specimen size on both the geometry of the fracture and its surface characterization. The analysis shows that fracture characteristics are substantially different between natural shear and artificial tensile fractures, while natural tensile fracture often spans the whole result domain of the two other fracture types. Specimen size effects are also evident, not only as scale sensitivity in the roughness metrics, but also as a by-product of the physical processes used to generate the fractures. Results from fractures generated with Brazilian tests show that fracture roughness at small scales differentiates fractures from different specimen sizes and stresses at failure.

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.

Novel classification system of rib fractures observed in infants.

PubMed

Love, Jennifer C; Derrick, Sharon M; Wiersema, Jason M; Pinto, Deborrah C; Greeley, Christopher; Donaruma-Kwoh, Marcella; Bista, Bibek

2013-03-01

Rib fractures are considered highly suspicious for nonaccidental injury in the pediatric clinical literature; however, a rib fracture classification system has not been developed. As an aid and impetus for rib fracture research, we developed a concise schema for classifying rib fracture types and fracture location that is applicable to infants. The system defined four fracture types (sternal end, buckle, transverse, and oblique) and four regions of the rib (posterior, posterolateral, anterolateral, and anterior). It was applied to all rib fractures observed during 85 consecutive infant autopsies. Rib fractures were found in 24 (28%) of the cases. A total of 158 rib fractures were identified. The proposed schema was adequate to classify 153 (97%) of the observed fractures. The results indicate that the classification system is sufficiently robust to classify rib fractures typically observed in infants and should be used by researchers investigating infant rib fractures. © 2013 American Academy of Forensic Sciences.

Characteristics of fractures in crystalline bedrock determined by surface and borehole geophysical surveys, eastern surplus superfund site, Meddybemps, Maine

USGS Publications Warehouse

Hansen, Bruce P.; Stone, Janet Radway; Lane, John W.

1999-01-01

Surface and borehole geophysical methods were used to determine fracture orientation in crystalline bedrock at the Eastern Surplus Superfund Site in Meddybemps, Maine. Fracture-orientation information is needed to address concerns about the fate of contaminants in ground water at the site. Azimuthal square-array resistivity surveys were conducted at 3 locations at the site, borehole-acoustic televiewer and borehole-video logs were collected in 10 wells, and single-hole directional radar surveys were conducted in 9 wells. Borehole-video logs were used to supplement the results of other geophysical techniques and are not described in this report. Analysis of azimuthal square-array resistivity data indicated that high-angle fracturing generally strikes northeast-southwest at the three locations. Borehole-acoustic televiewer logs detected one prominent low-angle and two prominent high-angle fracture sets. The low-angle fractures strike generally north-northeast and dip about 20 degrees west-northwest. One high-angle fracture set strikes north-northeast and dips east-southeast; the other high-angle set strikes east-northeast and dips south-southeast. Single-hole directional radar surveys identified two prominent fracture sets: a low-angle set striking north-northeast, dipping west-northwest; and a high-angle fracture set striking north-northeast, dipping east-southeast. Two additional high-angle fracture sets are defined weakly, one striking east-west, dipping north; and a second striking east-west, dipping south. Integrated results from all of the geophysical surveys indicate the presence of three primary fracture sets. A low-angle set strikes north-northeast and dips west-northwest. Two high-angle sets strike north-northeast and east-northeast and dip east-southeast and south-southeast. Statistical correction of the fracture data for orientation bias indicates that high-angle fractures are more numerous than observed in the data but are still less numerous than the low-angle fractures. The orientation and distribution of water-yielding fractures sets were determined by correlating the fracture data from this study with previously collected borehole-flowmeter data. The water-yielding fractures are generally within the three prominent fracture sets observed for the total fracture population. The low-angle water-yielding fractures primarily strike north-northeast to west-northwest and dip west-northwest to south-southwest. Most of the high-angle water-yielding fractures strike either north-northeast or east-west and dip east-southeast or south. The spacing between water-yielding fractures varies but the probable average spacing is estimated to be 30 feet for low-angle fractures; 27 feet for the east-southeast dipping, high-angle fractures; and 43 feet for the south-southeast dipping, high-angle fractures. The median estimated apparent transmissivity of individual water-yielding fractures or fracture zones was 0.3 feet squared per day and ranged from 0.01 to 382 feet squared per day. Ninety-five percent of the water-yielding fractures or fracture zones had an estimated apparent transmissivity of 19.5 feet squared per day or less. The orientation, spacing, and hydraulic properties of water-yielding fractures identified during this study can be used to help estimate recharge, flow, and discharge of ground water contaminants. High-angle fractures provide vertical pathways for ground water to enter the bedrock, interconnections between low-angle fractures, and, subsequently, pathways for water flow within the bedrock along fracture planes. Low-angle fractures may allow horizontal ground-water flow in all directions. The orientation of fracturing and the hydraulic properties of each fracture set strongly affect changes in ground-water flow under stress (pumping) conditions.

Innovations in the management of hip fractures.

PubMed

Teasdall, Robert D; Webb, Lawrence X

2003-08-01

Hip fractures include fractures of the head, neck, intertrochanteric, and subtrochanteric regions. Head fractures commonly accompany dislocations. Neck fractures and intertrochanteric fractures occur with greatest frequency in elderly patients with a low bone mineral density and are produced by low-energy mechanisms. Subtrochanteric fractures occur in a predominantly strong cortical osseous region that is exposed to large compressive stresses. Implants used to address these fractures must accommodate significant loads while the fractures consolidate. Complications secondary to hip fractures produce significant morbidity and include infection, nonunion, malunion, decubitus ulcers, fat emboli, deep venous thrombosis, pulmonary embolus, pneumonia, myocardial infarction, stroke, and death.

Complexin Mutants Reveal Partial Segregation between Recycling Pathways That Drive Evoked and Spontaneous Neurotransmission

PubMed Central

Sabeva, Nadezhda; Cho, Richard W.; Vasin, Alexander; Gonzalez, Agustin; Littleton, J. Troy

2017-01-01

Synaptic vesicles fuse at morphological specializations in the presynaptic terminal termed active zones (AZs). Vesicle fusion can occur spontaneously or in response to an action potential. Following fusion, vesicles are retrieved and recycled within nerve terminals. It is still unclear whether vesicles that fuse spontaneously or following evoked release share similar recycling mechanisms. Genetic deletion of the SNARE-binding protein complexin dramatically increases spontaneous fusion, with the protein serving as the synaptic vesicle fusion clamp at Drosophila synapses. We examined synaptic vesicle recycling pathways at complexin null neuromuscular junctions, where spontaneous release is dramatically enhanced. We combined loading of the lipophilic dye FM1–43 with photoconversion, electron microscopy, and electrophysiology to monitor evoked and spontaneous recycling vesicle pools. We found that the total number of recycling vesicles was equal to those retrieved through spontaneous and evoked pools, suggesting that retrieval following fusion is partially segregated for spontaneous and evoked release. In addition, the kinetics of FM1–43 destaining and synaptic depression measured in the presence of the vesicle-refilling blocker bafilomycin indicated that spontaneous and evoked recycling pools partially intermix during the release process. Finally, FM1–43 photoconversion combined with electron microscopy analysis indicated that spontaneous recycling preferentially involves synaptic vesicles in the vicinity of AZs, whereas vesicles recycled following evoked release involve a larger intraterminal pool. Together, these results suggest that spontaneous and evoked vesicles use separable recycling pathways and then partially intermix during subsequent rounds of fusion. SIGNIFICANCE STATEMENT Neurotransmitter release involves fusion of synaptic vesicles with the plasma membrane in response to an action potential, or spontaneously in the absence of stimulation. Upon fusion, vesicles are retrieved and recycled, and it is unclear whether recycling pathways for evoked and spontaneous vesicles are segregated after fusion. We addressed this question by taking advantage of preparations lacking the synaptic protein complexin, which have elevated spontaneous release that enables reliable tracking of the spontaneous recycling pool. Our results suggest that spontaneous and evoked recycling pathways are segregated during the retrieval process but can partially intermix during stimulation. PMID:28077717

Characteristic Fracture Spacing in Primary and Secondary Recovery from Naturally Fractured Reservoirs

NASA Astrophysics Data System (ADS)

Gong, J.; Rossen, W.

2015-12-01

We showed previously (Gong and Rossen, 2014a,b) that, if the fracture aperture distribution is broad enough in a naturally fractured reservoir, even one where the fracture network is well-connected, most fractures can be eliminated without significantly affecting the flow through the fracture network. During a waterflood or enhanced-oil-recovery (EOR) process, the production of oil depends on the supply of injected water or EOR agent. This suggests that the characteristic fracture spacing for the dual-porosity/dual-permeability simulation of waterflood or EOR in a naturally fractured reservoir should account not for all fractures but only the relatively small portion of the fracture network carrying almost all the injected water or EOR agent. In contrast, in primary production even a relatively small fracture represents an effective path for oil to flow to a production well. Thus in primary production the effective fracture spacing should include all the fractures. This distinction means that the "shape factor" in dual-porosity/dual-permeability reservoir simulators and the repeating unit in homogenization should depend on the process involved: specifically, it should be different for primary and secondary or tertiary recovery. We test this hypothesis in a simple representation of a fractured reservoir with a non-uniform distribution of fracture flow conductivities. We compare oil production, flow patterns in matrix, and the pattern of oil recovery around fractures with and without the "unimportant" fractures present. In primary production, all fractures which are much more permeable than matrix play a significant role in production. The shape factor or repeating-unit size should reflect the entire fracture distribution. In secondary or tertiary production, the role of fractures that carry relatively little flow depends on injection rate, the ratio of flow carried by the different fractures, and the permeability of matrix. In some cases, the appropriate shape factor or repeating-unit size for waterflood or EOR should reflect only those fractures that carry most of the flow. References:Gong, and Rossen, 14th ECMOR Conf., Catania, Sicily, 2014(a). Gong, and Rossen, Intl. Discrete Fracture Network Eng. Conf., Vancouver, Canada, 2014(b).

The relationship of fall-related fractures to social deprivation.

PubMed

Court-Brown, C M; Aitken, S A; Ralston, S H; McQueen, M M

2011-04-01

The relationship between fall-related fractures and social deprivation was studied in 3,843 patients. The incidence of fractures correlated with deprivation in all age groups although the spectrum of fractures was not affected by deprivation. The average age and the prevalence of hip fractures decreased with increasing deprivation. This study examines the relationship between social deprivation and fall-related fractures. Social deprivation has been shown to be a predisposing factor in a number of diseases. There is evidence that it is implicated in fractures in children and young adults, but the evidence that it is associated with fragility fractures in older adults is weak. As fragility fractures are becoming progressively more common and increasingly expensive to treat, the association between social deprivation and fractures is important to define. All out-patient and in-patient fractures presenting to the Royal Infirmary of Edinburgh over a 1-year period were prospectively recorded. The fractures caused by falls from a standing height were analysed in all patients of at least 15 years of age. Social deprivation was assessed using the Carstairs score and social deprivation deciles, and the 2001 census was used to calculate fracture incidence. The data were used to analyse the relationship between social deprivation and fall-related fractures in all age groups. The incidence of fall-related fractures correlated with social deprivation in all age groups including fragility fractures in the elderly. The overall spectrum of fractures was not affected by social deprivation although the prevalence of proximal femoral fractures decreased with increasing deprivation. The average age of patients with fall-related fractures also decreased with increasing social deprivation as did the requirement for in-patient treatment. This is the first study to show the relationship between fall-related fractures and social deprivation in older patients. We believe that the decreased incidence of proximal femoral fractures, and the lower average age of patients with fall-related fractures, in the socially deprived relates to the relative life expectancies in the different deprivation deciles.

Non-catastrophic and catastrophic fractures in racing Thoroughbreds at the Hong Kong Jockey Club.

PubMed

Sun, T C; Riggs, C M; Cogger, N; Wright, J; Al-Alawneh, J I

2018-04-19

Reports of fractures in racehorses have predominantly focused on catastrophic injuries, and there is limited data identifying the location and incidence of fractures that did not result in a fatal outcome. To describe the nature and the incidence of non-catastrophic and catastrophic fractures in Thoroughbreds racing at the Hong Kong Jockey Club (HKJC) over seven racing seasons. Retrospective cohort study. Data of fractures sustained in horses while racing and of race characteristics were extracted from the HKJC Veterinary Management Information System (VMIS) and Racing Information System (RIS) respectively. The fracture event was determined from the first clinical entry for each specific injury. The incidence rates of non-catastrophic and catastrophic fractures were calculated per 1000 racing starts for racetrack, age, racing season, sex and trainer. 179 first fracture events occurred in 64,807 racing starts. The incidence rate of non-catastrophic fractures was 2.2 per 1000 racing starts and of catastrophic fractures was 0.6 per 1000 racing starts. Fractures of the proximal sesamoid bones represented 55% of all catastrophic fractures while the most common non-catastrophic fractures involved the carpus and the first phalanx. Significant associations were detected between the incidence of non-catastrophic fractures and sex, trainer and racing season. The first fracture event was used to calculate the incidence rate in this study and may have resulted in underestimation of the true incidence rate of fractures in this population. However, given the low number of recorded fracture events compared to the size of the study population, this underestimation is likely to be small. There were 3.6 times as many non-catastrophic fractures as catastrophic fractures in Thoroughbreds racing in Hong Kong between 2004 and 2011. Non-catastrophic fractures interfere with race training schedules and may predispose to catastrophic fracture. Future analytical studies on non-catastrophic racing fractures should be a priority for the racing industry. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Experimental analysis of multiple factors on hydraulic fracturing in coalbed methane reservoirs

PubMed Central

Ma, Geng; Liu, Xiao; Tao, Yunqi; Feng, Dan; Li, Rui

2018-01-01

Hydraulic fracturing can improve the permeability of coalbed methane (CBM) reservoirs effectively, which is of great significance to the commercial production of CBM. However, the efficiency of hydraulic fracturing is affected by multiple factors. The mechanism of fracture initiation, morphology and propagation in CBM reservoirs is not clear and need to be further explored. Hydraulic fracturing experiment is an accurate tool to explore these mechanisms. The quantity of experimental coal rock is large and processing method is complex, so specimen made of similar materials was applied to replace coal rock. The true triaxial hydraulic fracturing experimental apparatus, 3D scanning device for coal rock section were applied to carry out hydraulic fracturing experiment. The results show that the initiation pressure is inversely proportional to the horizontal stress difference (Δσ) and positively related to fracturing fluid injection rate. When vertical stress (σv) is constant, the initiation pressure and fracture width decrease with the increasing of Δσ. Natural fractures can be connected by main fracture when propagates perpendicular to the direction of minimum horizontal stress (σh), then secondary fractures and fracture network form in CBM reservoirs. When two stresses of crustal stress are close and far different from the third one, the fracture morphology and propagation become complex. Influenced by perforations and filtration of fracturing fluid in specimen, fracturing fluid flows to downward easily after comparing horizontal well fracturing with vertical well fracturing. Fracture width increases with the decreasing of elastic modulus, the intensity of fracture is positively related with the elastic modulus of coal rock. The research results can provide theoretical basis and technical support for the efficient development of CBM. PMID:29621295

Correlation of Hip Fracture with Other Fracture Types: Toward a Rational Composite Hip Fracture Endpoint

PubMed Central

Colón-Emeric, Cathleen; Pieper, Carl F.; Grubber, Janet; Van Scoyoc, Lynn; Schnell, Merritt L; Van Houtven, Courtney Harold; Pearson, Megan; Lafleur, Joanne; Lyles, Kenneth W.; Adler, Robert A.

2016-01-01

Purpose With ethical requirements to the enrollment of lower risk subjects, osteoporosis trials are underpowered to detect reduction in hip fractures. Different skeletal sites have different levels of fracture risk and response to treatment. We sought to identify fracture sites which cluster with hip fracture at higher than expected frequency; if these sites respond to treatment similarly, then a composite fracture endpoint could provide a better estimate of hip fracture reduction. Methods Cohort study using Veterans Affairs and Medicare administrative data. Male Veterans (n=5,036,536) aged 50-99 years receiving VA primary care between1999-2009 were included. Fractures were ascertained using ICD9 and CPT codes and classified by skeletal site. Pearson correlation coefficients, logistic regression and kappa statistics, were used to describe the correlation between each fracture type and hip fracture within individuals, without regards to the timing of the events. Results 595,579 (11.8%) men suffered 1 or more fractures and 179,597 (3.6%) suffered 2 or more fractures during the time under study. Of those with one or more fractures, rib was the most common site (29%), followed by spine (22%), hip (21%) and femur (20%). The fracture types most highly correlated with hip fracture were pelvic/acetabular (Pearson correlation coefficient 0.25, p<0.0001), femur (0.15, p<0.0001), and shoulder (0.11, p<0.0001). Conclusions Pelvic, acetabular, femur, and shoulder fractures cluster with hip fractures within individuals at greater than expected frequency. If we observe similar treatment risk reductions within that cluster, subsequent trials could consider use of a composite endpoint to better estimate hip fracture risk. PMID:26151123

The second fracture of the same clavicle: prevalence and fracture configurations.

PubMed

Asavamongkolkul, Apichat; Harnroongroj, Thos; Suteeraporn, Wuttipon; Sudjai, Narumol; Harnroongroj, Thossart

2012-12-01

To study second fracture at the same clavicle including prevalence, fracture configurations related to malunion types of the first fracture, and healing. Between 2008 and 2011, the authors reviewed medical records and radiographs of the clavicles of patients who sustained acute clavicular fractures from motorcycle accident. Second fracture at the same clavicle and prevalence were studied. Malunion of the first fracture of the same clavicle were typed and configurations of the second fracture at the same clavicles were described related to type of the malunion. There were 552 clavicular fractures. Four cases of which sustained a second fracture at the same clavicles. Malunion of the first clavicular fracture of the four cases were typed: type I, extension, type II, flexion, and type III, bayonet. There were one, two, and one case of second clavicular fractures of the type I, II, and III clavicular malunion. The configuration of second clavicular fracture of the type I malunion clavicle is located at lateral fragment, inferior displacement, and dorsal angulation with dorsal cortex conminution. The type II malunion clavicle is located at lateral fragment with minimal displacement. For the type III malunion clavicle, the second fracture is located at medial fragment with mild inferior displacement and inferior angulation. The four cases of the second fractures of the same clavicles healed within two months without complication. The prevalence of second fracture at the same clacicles was 7.2:1000. The three types of the first fracture malunion were extension, flexion, and bayonet. The configuration of the second fracture at the same clavicles depends on malunion types of the first clavicular fracture. They healed without complication.

Experimental analysis of multiple factors on hydraulic fracturing in coalbed methane reservoirs.

PubMed

Zhang, Fan; Ma, Geng; Liu, Xiao; Tao, Yunqi; Feng, Dan; Li, Rui

2018-01-01

Hydraulic fracturing can improve the permeability of coalbed methane (CBM) reservoirs effectively, which is of great significance to the commercial production of CBM. However, the efficiency of hydraulic fracturing is affected by multiple factors. The mechanism of fracture initiation, morphology and propagation in CBM reservoirs is not clear and need to be further explored. Hydraulic fracturing experiment is an accurate tool to explore these mechanisms. The quantity of experimental coal rock is large and processing method is complex, so specimen made of similar materials was applied to replace coal rock. The true triaxial hydraulic fracturing experimental apparatus, 3D scanning device for coal rock section were applied to carry out hydraulic fracturing experiment. The results show that the initiation pressure is inversely proportional to the horizontal stress difference (Δσ) and positively related to fracturing fluid injection rate. When vertical stress (σv) is constant, the initiation pressure and fracture width decrease with the increasing of Δσ. Natural fractures can be connected by main fracture when propagates perpendicular to the direction of minimum horizontal stress (σh), then secondary fractures and fracture network form in CBM reservoirs. When two stresses of crustal stress are close and far different from the third one, the fracture morphology and propagation become complex. Influenced by perforations and filtration of fracturing fluid in specimen, fracturing fluid flows to downward easily after comparing horizontal well fracturing with vertical well fracturing. Fracture width increases with the decreasing of elastic modulus, the intensity of fracture is positively related with the elastic modulus of coal rock. The research results can provide theoretical basis and technical support for the efficient development of CBM.

Risk factors for distal radius fracture in postmenopausal women.

PubMed

Xu, Wenting; Ni, Cheng; Yu, Ren; Gu, Guoqing; Wang, Zheren; Zheng, Guoqing

2017-05-01

The aim of this work was to explore the risk factors for distal radius fracture in postmenopausal women. A total of 611 postmenopausal women with distal radius fractures were included. In all, 173 patients with unstable distal radius fractures were included (unstable fracture group), while there were 438 patients with stable distal radius fractures (stable fracture group). The control group comprised 800 postmenopausal women with no fracture. A questionnaire survey was conducted. Compared with the control group, the 611 postmenopausal women with distal radius fractures had a higher body mass index (BMI). Advanced age and higher BMI were more common in the unstable fracture group than in the stable fracture group (P <0.05). A higher proportion of the 611 postmenopausal women with a distal radius fracture had fallen in the last 12 months than in the control group. Comorbidities and the frequency of falls in the last 12 months were higher in the unstable fracture group than in the stable fracture group (P < 0.05). A higher proportion of the control group was taking calcium supplements, while the proportion taking calcium supplementation in the unstable fracture group was lower than that in the stable fracture group (P < 0.05). Osteoporosis in the two fracture groups (P < 0.05) was significantly higher than in the control group and was the highest in the unstable fracture group (P < 0.05). In postmenopausal women, obesity, falls, unknown osteoporosis status, and osteoporosis are associated with high risk of distal radius fracture. If comorbidities and advanced age are also present, this group of persons may be at higher risk for unstable distal radius fractures.

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 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.

Fluid driven fracture mechanics in highly anisotropic shale: a laboratory study with application to hydraulic fracturing

NASA Astrophysics Data System (ADS)

Gehne, Stephan; Benson, Philip; Koor, Nick; Enfield, Mark

2017-04-01

The finding of considerable volumes of hydrocarbon resources within tight sedimentary rock formations in the UK led to focused attention on the fundamental fracture properties of low permeability rock types and hydraulic fracturing. Despite much research in these fields, there remains a scarcity of available experimental data concerning the fracture mechanics of fluid driven fracturing and the fracture properties of anisotropic, low permeability rock types. In this study, hydraulic fracturing is simulated in a controlled laboratory environment to track fracture nucleation (location) and propagation (velocity) in space and time and assess how environmental factors and rock properties influence the fracture process and the developing fracture network. Here we report data on employing fluid overpressure to generate a permeable network of micro tensile fractures in a highly anisotropic shale ( 50% P-wave velocity anisotropy). Experiments are carried out in a triaxial deformation apparatus using cylindrical samples. The bedding planes are orientated either parallel or normal to the major principal stress direction (σ1). A newly developed technique, using a steel guide arrangement to direct pressurised fluid into a sealed section of an axially drilled conduit, allows the pore fluid to contact the rock directly and to initiate tensile fractures from the pre-defined zone inside the sample. Acoustic Emission location is used to record and map the nucleation and development of the micro-fracture network. Indirect tensile strength measurements at atmospheric pressure show a high tensile strength anisotropy ( 60%) of the shale. Depending on the relative bedding orientation within the stress field, we find that fluid induced fractures in the sample propagate in two of the three principal fracture orientations: Divider and Short-Transverse. The fracture progresses parallel to the bedding plane (Short-Transverse orientation) if the bedding plane is aligned (parallel) with the direction of σ1. Conversely, the crack plane develops perpendicular to the bedding plane, if the bedding plane is orientated normal to σ1. Fracture initiation pressures are higher in the Divider orientation ( 24MPa) than in the Short-Transverse orientation ( 14MPa) showing a tensile strength anisotropy ( 42%) comparable to ambient tensile strength results. We then use X-Ray Computed Tomography (CT) 3D-images to evaluate the evolved fracture network in terms of fracture pattern, aperture and post-test water permeability. For both fracture orientations, very fine, axial fractures evolve over the entire length of the sample. For the fracturing in the Divider orientation, it has been observed, that in some cases, secondary fractures are branching of the main fracture. Test data from fluid driven fracturing experiments suggest that fracture pattern, fracture propagation trajectories and fracturing fluid pressure (initiation and propagation pressure) are predominantly controlled by the interaction between the anisotropic mechanical properties of the shale and the anisotropic stress environment. The orientation of inherent rock anisotropy relative to the principal stress directions seems to be the main control on fracture orientation and required fracturing pressure.

Genetic research of fractures in carbonate reservoir: a case study of NT carbonate reservoir in the pre-Caspian basin

NASA Astrophysics Data System (ADS)

Fan, Zifei; Wang, Shuqin; Li, Jianxin; Zhao, Wenqi; Sun, Meng; Li, Weiqiang; Li, Changhai

2018-02-01

The degree of development and characteristics of fractures are key factors for the appraisal of carbonate reservoirs. In this paper, core data and well logging data from the NT oilfield in the Pre-Caspian Basin are used to study the formation mechanism and distribution characteristics of different genetic fractures, and analyze their influence on reservoir properties. Fractures in carbonate reservoirs can be divided into three categories according to their formation mechanism; these are tectonic fracture, dissolved fracture, and diagenetic fracture,which is further divided into interlayer fracture and stylolite. Fractures of different formation mechanism influence fluid seepage in different degree, tectonic fractures possessing strong connecting ability to pores, and dissolved fractures also improving reservoir properties effectively, however, diagenetic fractures contributing relatively little to fluid seepage.

Fracture line morphology of complex proximal humeral fractures.

PubMed

Hasan, Afsana P; Phadnis, Joideep; Jaarsma, Ruurd L; Bain, Gregory I

2017-10-01

The aim of this study was to assess proximal humeral fracture patterns using 3-dimensional computed tomography images and relate them to the normal osseous landmarks and soft-tissue attachments. Forty-eight 3-dimensional computed tomography scans of proximal humeral fractures were retrospectively collected, and the fractures were transcribed onto proximal humeral templates. We analyzed the common location and orientation of the fracture lines, with a focus on fractures of the articular surface, tuberosities, metaphysis, and proximal diaphysis. These fractures were compared with the attachments of the rotator cuff and glenohumeral capsule. Fifty-two percent of the fractures involved the articular surface. No fractures passed through the bicipital groove, and fractures were more commonly found on the posterior lesser tuberosity and on the anterior greater tuberosity, coinciding with the intervals between the rotator cuff tendon insertions. Intracapsular fractures of the calcar were more common (68%) than extracapsular fractures (32%). On the anterolateral aspect of the proximal humerus, fractures radiated from the articular margin, vertically down through the tuberosity zone between the rotator cuff footprints, meeting horizontally oriented fractures in the metaphyseal zone. On the posterior aspect, vertical fractures from the tuberosity zone continued downward to the metaphyseal zone adjacent to the infraspinatus and teres minor footprints. Fractures of the proximal humerus follow characteristic patterns. Fractures frequently split the greater tuberosity and are closely related to the intervals of the rotator cuff attachments. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Implications of heterogeneous fracture distribution on reservoir quality; an analogue from the Torridon Group sandstone, Moine Thrust Belt, NW Scotland

NASA Astrophysics Data System (ADS)

Watkins, Hannah; Healy, David; Bond, Clare E.; Butler, Robert W. H.

2018-03-01

Understanding fracture network variation is fundamental in characterising fractured reservoirs. Simple relationships between fractures, stress and strain are commonly assumed in fold-thrust structures, inferring relatively homogeneous fracture patterns. In reality fractures are more complex, commonly appearing as heterogeneous networks at outcrop. We use the Achnashellach Culmination (NW Scotland) as an outcrop analogue to a folded tight sandstone reservoir in a thrust belt. We present fracture data is collected from four fold-thrust structures to determine how fracture connectivity, orientation, permeability anisotropy and fill vary at different structural positions. We use a 3D model of the field area, constructed using field observations and bedding data, and geomechanically restored using Move software, to determine how factors such as fold curvature and strain influence fracture variation. Fracture patterns in the Torridon Group are consistent and predictable in high strain forelimbs, however in low strain backlimbs fracture patterns are inconsistent. Heterogeneities in fracture connectivity and orientation in low strain regions do not correspond to fluctuations in strain or fold curvature. We infer that where strain is low, other factors such as lithology have a greater control on fracture formation. Despite unpredictable fracture attributes in low strain regions, fractured reservoir quality would be highest here because fractures in high strain forelimbs are infilled with quartz. Heterogeneities in fracture attribute data on fold backlimbs mean that fractured reservoir quality and reservoir potential is difficult to predict.

Percolation Laws of a Fractal Fracture-Pore Double Medium

NASA Astrophysics Data System (ADS)

Zhao, Yangsheng; Feng, Zengchao; Lv, Zhaoxing; Zhao, Dong; Liang, Weiguo

2016-12-01

The fracture-pore double porosity medium is one of the most common media in nature, for example, rock mass in strata. Fracture has a more significant effect on fluid flow than a pore in a fracture-pore double porosity medium. Hence, the fracture effect on percolation should be considered when studying the percolation phenomenon in porous media. In this paper, based on the fractal distribution law, three-dimensional (3D) fracture surfaces, and two-dimensional (2D) fracture traces in rock mass, the locations of fracture surfaces or traces are determined using a random function of uniform distribution. Pores are superimposed to build a fractal fracture-pore double medium. Numerical experiments were performed to show percolation phenomena in the fracture-pore double medium. The percolation threshold can be determined from three independent variables (porosity n, fracture fractal dimension D, and initial value of fracture number N0). Once any two are determined, the percolation probability exists at a critical point with the remaining parameter changing. When the initial value of the fracture number is greater than zero, the percolation threshold in the fracture-pore medium is much smaller than that in a pore medium. When the fracture number equals zero, the fracture-pore medium degenerates to a pore medium, and both percolation thresholds are the same.

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.

Influence of natural fractures on hydraulic fracture propagation

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

Teufel, L.W.; Warpinski, N.R.

Hydraulic fracturing has become a valuable technique for the stimulation of oil, gas, and geothermal reservoirs in a variety of reservoir rocks. In many applications, only short fractures are needed for economic production. In low-permeability reservoirs, however, long penetrating fractures are generally needed, and in this case, natural fractures can be the cause of many adverse effects during a fracture treatment. Natural fractures can influence the overall geometry and effectiveness of the hydraulic fracture by: (1) arresting the vertical or lateral growth, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing themore » creation of multiple or secondary fractures rather than a single planar hydraulic fracture. The result may range from negligible to catastrophic depending on the values of the ancillary treatment and reservoir parameters, such as the treating pressure, in-situ stresses, pore pressure, orientations of the natural fractures relative to principal in-situ stresses, spacing and distribution of the natural fractures, permeability, etc. Field observations from mineback experiments at DOE's Nevada Test Site and the multiwell experiment in Colorado, laboratory tests, and analyses of these data are integrated to describe the complex fracture behavior found and to provide guidelines for predicting when this complex fracturing will occur.« less

Influence of natural fractures on hydraulic fracture propagation

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

Teufel, L.W.; Warpinski, N.R.

Hydraulic fracturing has become a valuable technique for the stimulation of oil, gas, and geothermal reservoirs in a variety of reservoir rocks. In many applications, only short fractures are needed for economic production. In low-permeability reservoirs, however, long penetrating fractures are generally needed, and in this case, natural fractures can be the cause of many adverse effects during a fracture treatment. Natural fractures can influence the overall geometry and effectiveness of the hydraulic fracture by: (1) arresting the vertical or lateral growth, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing themore » creation of multiple or secondary fractures rather than a single planar hydraulic fracture. The result may range from negligible to catastrophic depending on the values of the ancillary treatment and reservoir parameters, such as the treating pressure, in-situ stresses, pore pressure, orientations of the natural fractures relative to principle in-situ stresses, spacing and distribution of the natural fractures, permeability, etc. Field observations from mineback experiments at DOE's Nevada Test Site and the multiwell experiment in Colorado, laboratory tests, and analyses of these data are integrated to describe the complex fracture behavior found to an provide guidelines for predicting when this complex fracturing occurs.« less

Borehole sampling of fracture populations - compensating for borehole sampling bias in crystalline bedrock aquifers, Mirror Lake, Grafton County, New Hampshire

USGS Publications Warehouse

McDonald, G.D.; Paillet, Frederick L.; Barton, C.C.; Johnson, C.D.

1997-01-01

The clustering of orientations of hydraulically conductive fractures in bedrock at the Mirror Lake, New Hampshire fractured rock study site was investigated by comparing the orientations of fracture populations in two subvertical borehole arrays with those mapped on four adjacent subvertical roadcuts. In the boreholes and the roadcuts, the orientation of fracture populations appears very similar after borehole data are compensated for undersampling of steeply dipping fractures. Compensated borehole and pavement fracture data indicate a northeast-striking population of fractures with varying dips concentrated near that of the local foliation in the adjacent rock. The data show no correlation between fracture density (fractures/linear meter) and distance from lithologic contacts in both the boreholes and the roadcuts. The population of water-producing borehole fractures is too small (28 out of 610 fractures) to yield meaningful orientation comparisons. However, the orientation of large aperture fractures (which contains all the producing fractures) contains two or three subsidiary clusters in orientation frequency that are not evident in stereographic projections of the entire population containing all aperture sizes. Further, these subsidiary orientation clusters do not coincide with the dominant (subhorizontal and subvertical) regional fracture orientations.

Major factors controlling fracture development in the Middle Permian Lucaogou Formation tight oil reservoir, Junggar Basin, NW China

NASA Astrophysics Data System (ADS)

Zhang, Chen; Zhu, Deyu; Luo, Qun; Liu, Luofu; Liu, Dongdong; Yan, Lin; Zhang, Yunzhao

2017-09-01

Natural fractures in seven wells from the Middle Permian Lucaogou Formation in the Junggar Basin were evaluated in light of regional structural evolution, tight reservoir geochemistry (including TOC and mineral composition), carbon and oxygen isotopes of calcite-filled fractures, and acoustic emission (AE). Factors controlling the development of natural fractures were analyzed using qualitative and/or semi-quantitative techniques, with results showing that tectonic factors are the primary control on fracture development in the Middle Permian Lucaogou Formation of the Junggar Basin. Analyses of calcite, dolomite, and TOC show positive correlations with the number of fractures, while deltaic lithofacies appear to be the most favorable for fracture development. Mineral content was found to be a major control on tectonic fracture development, while TOC content and sedimentary facies mainly control bedding fractures. Carbon and oxygen isotopes vary greatly in calcite-filled fractures (δ13C ranges from 0.87‰ to 7.98‰, while δ18O ranges from -12.63‰ to -5.65‰), indicating that fracture development increases with intensified tectonic activity or enhanced diagenetic alteration. By analyzing the cross-cutting relationships of fractures in core, as well as four Kaiser Effect points in the acoustic emission curve, we observed four stages of tectonic fracture development. First-stage fractures are extensional, and were generated in the late Triassic, with calcite fracture fills formed between 36.51 °C and 56.89 °C. Second-stage fractures are shear fractures caused by extrusion stress from the southwest to the northeast, generated by the rapid uplift of the Tianshan in the Middle and Late Jurassic; calcite fracture fills formed between 62.91 °C and 69.88 °C. Third-stage fractures are NNW-trending shear fractures that resulted from north-south extrusion and thrusting in a foreland depression along the front of the Early Cretaceous Bogda Mountains. Calcite fracture fills formed between 81.74 °C and 85.43 °C. Fourth-stage fractures inherited the tectonic framework of the third stage, resulting in fractures with the same orientation, but without calcite filling. By differentiating the various stages of fracture development, we were able to better understand the origin of fractures in tight oil reservoirs and their significance for exploration and development.

Acetabular fractures: anatomic and clinical considerations.

PubMed

Lawrence, David A; Menn, Kirsten; Baumgaertner, Michael; Haims, Andrew H

2013-09-01

Classifying acetabular fractures can be an intimidating topic. However, it is helpful to remember that there are only three basic types of acetabular fractures: column fractures, transverse fractures, and wall fractures. Within this framework, acetabular fractures are classified into two broad categories: elementary or associated fractures. We will review the osseous anatomy of the pelvis and provide systematic approaches for reviewing both radiographs and CT scans to effectively evaluate the acetabulum. Although acetabular fracture classification may seem intimidating, the descriptions and distinctions discussed and shown in this article hopefully make the topic simpler to understand. Approach the task by recalling that there are only three basic types of acetabular fractures: column fractures (coronally oriented on CT images), transverse fractures (sagittally oriented on CT images), and wall fractures (obliquely oriented on CT images). We have provided systematic approaches for reviewing both conventional radiographs and CT scans to effectively assess the acetabulum. The clinical implications of the different fracture patterns have also been reviewed because it is critically important to include pertinent information for our clinical colleagues to provide the most efficient and timely clinical care.

TOUGH-RBSN simulator for hydraulic fracture propagation within fractured media: Model validations against laboratory experiments

NASA Astrophysics Data System (ADS)

Kim, Kunhwi; Rutqvist, Jonny; Nakagawa, Seiji; Birkholzer, Jens

2017-11-01

This paper presents coupled hydro-mechanical modeling of hydraulic fracturing processes in complex fractured media using a discrete fracture network (DFN) approach. The individual physical processes in the fracture propagation are represented by separate program modules: the TOUGH2 code for multiphase flow and mass transport based on the finite volume approach; and the rigid-body-spring network (RBSN) model for mechanical and fracture-damage behavior, which are coupled with each other. Fractures are modeled as discrete features, of which the hydrological properties are evaluated from the fracture deformation and aperture change. The verification of the TOUGH-RBSN code is performed against a 2D analytical model for single hydraulic fracture propagation. Subsequently, modeling capabilities for hydraulic fracturing are demonstrated through simulations of laboratory experiments conducted on rock-analogue (soda-lime glass) samples containing a designed network of pre-existing fractures. Sensitivity analyses are also conducted by changing the modeling parameters, such as viscosity of injected fluid, strength of pre-existing fractures, and confining stress conditions. The hydraulic fracturing characteristics attributed to the modeling parameters are investigated through comparisons of the simulation results.

Functional outcomes of conservatively treated clavicle fractures

PubMed Central

Bajuri, Mohd Yazid; Maidin, S; Rauf, A; Baharuddin, M; Harjeet, S

2011-01-01

OBJECTIVE: The main aim of the study was to analyze the outcomes of clavicle fractures in adults treated non-surgically and to evaluate the clinical effects of displacement, fracture patterns, fracture location, fracture comminution, shortening and fracture union on shoulder function. METHODS: Seventy clavicle fractures were non-surgically treated in the Orthopedics Department at the Tuanku Ja'afar General Hospital, a tertiary care hospital in Seremban, Malaysia, an average of six months after injury. The clavicle fractures were treated conservatively with an arm sling and a figure-eight splint for three weeks. No attempt was made to reduce displaced fractures, and the patients were allowed immediate free-shoulder mobilization, as tolerated. They were prospectively evaluated clinically and radiographically. Shoulder function was evaluated using the Constant scoring technique. RESULTS: There were statistically significant functional outcome impairments in non-surgically treated clavicle fractures that correlated with the fracture type (comminution), the fracture displacement (21 mm or more), shortening (15 mm or more) and the fracture union (malunion). CONCLUSION: This article reveals the need for surgical intervention to treat clavicle fractures and improve shoulder functional outcomes. PMID:21655759

Performance on physical function tests and the risk of fractures and admissions: Findings from a national health screening of 557,648 community-dwelling older adults.

PubMed

Chun, So Hyun; Cho, Belong; Yang, Hyung-Kook; Ahn, Eunmi; Han, Min Kyu; Oh, Bumjo; Shin, Dong Wook; Son, Ki Young

Falls and fractures in older adults are often preventable, yet remain major health concerns as comprehensive physical function assessment may not be readily available. This study investigated whether simple timed up and go test (TUG) and unipedal stance test (UST) are effective in identifying people with an increased risk of fractures, femoral fractures, or admissions due to femoral fractures. Community-dwelling Korean older adults aged 66 years participated in the Korean National Screening Program for the Transitional Ages (n=557,648) between 2007 and 2010. Overall fractures, femoral fractures, and admissions due to femoral fracture during this period were outcome measures. The outcome measures were overall fractures, femoral fractures, and admissions due to femoral fracture after the health screening. The associations between inferior physical function test results and outcome measures were evaluated. A total of 523,502 subjects were followed-up for a mean period of 1.42 years, which resulted in 12,965 subjects with any fractures. Fracture data were retrieved from medical claims record. Subjects who performed poorly on one or both of the two physical function tests experienced higher number of overall fractures (aHR 1.21, 95% CI: 1.16-1.26), femoral fractures (aHR 1.80, 95% CI: 1.59-2.17), and admissions due to femoral fractures (aHR 1.85, 95% CI: 1.55-2.22) as compared to subjects with normal results on both tests. Combining TUG and UST was not superior to performing UST alone in predicting the increased risk of overall fractures (p=0.347), femoral fractures (p=0.402) or admissions due to femoral fractures (p=0.774). Poor performance on physical performance tests is associated with a higher risk of overall fractures, femoral fractures and admissions due to femoral fractures. The TUG and UST can be used to identify community-dwelling older individuals who are more vulnerable to fractures. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Population-Wide Impact of Non-Hip Non-Vertebral Fractures on Mortality.

PubMed

Tran, Thach; Bliuc, Dana; van Geel, Tineke; Adachi, Jonathan D; Berger, Claudie; van den Bergh, Joop; Eisman, John A; Geusens, Piet; Goltzman, David; Hanley, David A; Josse, Robert G; Kaiser, Stephanie M; Kovacs, Christopher S; Langsetmo, Lisa; Prior, Jerilynn C; Nguyen, Tuan V; Center, Jacqueline R

2017-09-01

Data on long-term consequences of non-hip non-vertebral (NHNV) fractures, accounting for approximately two-thirds of all fragility fractures, are scanty. Our study aimed to quantify the population-wide impact of NHNV fractures on mortality. The national population-based prospective cohort study (Canadian Multicentre Osteoporosis Study) included 5526 community dwelling women and 2163 men aged 50 years or older followed from July 1995 to September 2013. Population impact number was used to quantify the average number of people for whom one death would be attributable to fracture and case impact number to quantify the number of deaths out of which one would be attributable to a fracture. There were 1370 fragility fractures followed by 296 deaths in women (mortality rate: 3.49; 95% CI, 3.11 to 3.91), and 302 fractures with 92 deaths in men (5.05; 95% CI, 4.12 to 6.20). NHNV fractures accounted for three-quarters of fractures. In women, the population-wide impact of NHNV fractures on mortality was greater than that of hip and vertebral fractures because of the greater number of NHNV fractures. Out of 800 women, one death was estimated to be attributable to a NHNV fracture, compared with one death in 2000 women attributable to hip or vertebral fracture. Similarly, out of 15 deaths in women, one was estimated to be attributable to a NHNV fracture, compared with one in over 40 deaths for hip or vertebral fracture. The impact of forearm fractures (ie, one death in 2400 women and one out of 42 deaths in women attributable to forearm fracture) was similar to that of hip, vertebral, or rib fractures. Similar, albeit not significant, results were noted for men. The study highlights the important contribution of NHNV fractures on mortality because many NHNV fracture types, except for the most distal fractures, have serious adverse consequences that affect a significant proportion of the population. © 2017 American Society for Bone and Mineral Research. © 2017 American Society for Bone and Mineral Research.

Epidemiology of fractures in people with severe and profound developmental disabilities

USGS Publications Warehouse

Glick, N.R.; Fischer, M.H.; Heisey, D.M.; Leverson, G.E.; Mann, D.C.

2005-01-01

Fractures are more prevalent among people with severe and profound developmental disabilities than in the general population. In order to characterize the tendency of these people to fracture, and to identify features that may guide the development of preventive strategies, we analyzed fracture epidemiology in people with severe and profound developmental disabilities who lived in a stable environment. Data from a 23-year longitudinal cohort registry of 1434 people with severe and profound developmental disabilities were analyzed to determine the effects of age, gender, mobility, bone fractured, month of fracture, and fracture history upon fracture rates. Eighty-five percent of all fractures involved the extremities. The overall fracture rate increased as mobility increased. In contrast, femoral shaft fracture risk was substantially higher in the least mobile [relative risk (RR), 10.36; 95% confidence interval (CI), 3.29-32.66] compared with the most mobile group. Although the overall fracture rate was not associated with age, the femoral shaft fractures decreased but hand/foot fractures increased with age. Overall fracture risk declined in August and September (RR, 0.70; 95% CI, 0.55-0.89), being especially prominent for tibial/fibular fractures (RR, 0.31; 95% CI, 0.13-0.70). Gender was not a factor in fracture risk. Two primary fracture mechanisms are apparent: one, largely associated with lack of weight-bearing in people with the least mobility, is exemplified by femoral fractures during non-traumatic events as simple as diapering or transfers; the other, probably due to movement- or fall-related trauma, is exemplified by hand/foot fractures in people who ambulate. The fracture experience of people with severe and profound developmental disabilities is unique and, because it differs qualitatively from postmenopausal osteoporosis, may require population-specific methods for assessing risk, for improving bone integrity, and for reduction of falls and accidents. ?? International Osteoporosis Foundation and National Osteoporosis Foundation 2004.

Hydro-fracture in the laboratory: matching diagnostic seismic signals to fracture networks

NASA Astrophysics Data System (ADS)

Gehne, S.; Benson, P. M.; Koor, N.; Dobson, K. J.; Enfield, M.; Barber, A.

2017-12-01

Hydraulic fracturing is a key process in both natural (e.g. dyke intrusion) and engineered environments (e.g. shale gas). To better understand this process, we present new data from simulated hydraulic fracturing in a controlled laboratory environment in order to track fracture nucleation (location) and propagation (velocity) in space and time to assess the fracture mechanics and developing fracture network. Fluid overpressure is used to generate a permeable network of micro tensile fractures in an anisotropic sandstone and a highly anisotropic shale. A newly developed technique, using a steel guide arrangement to direct pressurised fluid into a sealed section of an axially drilled conduit, allows the pore fluid to contact the rock directly and to initiate tensile fractures from a pre-defined zone inside the sample. Acoustic emission location is used to record and map the nucleation and development of the micro-fracture network. For both rock types, fractures progresses parallel to the bedding plane (short-transverse) if the bedding plane is aligned with the direction of σ1 requiring breakdown pressures of approximately 7 and 13MPa respectively at a confining pressure of 8MPa. The data also indicates a more ductile behaviour of the shale than expected. We use X-Ray Computed Tomography (CT) to evaluate the evolved fracture network in terms of fracture pattern and aperture. Hydraulic fracturing produces very planar fractures in the shale, with axial fractures over the entire length of the sample broadly following the bedding. In contrast, fractures in the sandstone are more diffuse, linking pore spaces as they propagate. However, secondary micro cracking, branching of the main fracture, are also observed. These new experiments suggest that fracture pattern, fracture propagation trajectories, and fracturing fluid pressures are predominantly controlled by the interaction between the anisotropic mechanical properties of the rock and the anisotropic stress environment.

Altered-stress fracturing

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

Warpinski, N.R.; Branagan, P.T.

Altered-stress fracturing is a concept whereby a hydraulic fracture in one well is reoriented by another hydraulic fracture in a nearby location. The application is in tight, naturally fractured, anisotropic reservoirs in which conventional hydraulic fractures parallel the highly permeable natural fractures and little production enhancement is achieved by conventional hydraulic fracturing. Altered-stress fracturing can modify the stress field so that hydraulic fractures propagate across the permeable natural fractures. A field test was conducted in which stress changes of 250 to 300 psi (1.7 to 2.1 MPa) were measured in an offset well 120 ft (37 m) away during relativelymore » small minifracs in a production well. These results show that stress-altered fracturing is possible at this site and others. Analytic and finite element calculations quantify the effects of layers, stresses, and crack size. Reservoir calculations show significant enhancement compared to conventional treatments. 21 refs., 12 figs., 3 tabs.« less

Isolated tympanic plate fracture frequency and its relationship to mandibular trauma.

PubMed

Altay, Canan; Erdoğan, Nezahat; Batkı, Ozan; Eren, Erdem; Altay, Sedat; Karasu, Sebnem; Mete, Berna; Uluç, Engin

2014-11-01

This study evaluated the prevalence of isolated tympanic fractures and their correlation with mandibular fractures by using maxillofacial computed tomography (CT). We retrospectively evaluated the maxillofacial CT of 1590 patients who presented to our emergency department with maxillofacial trauma between December 2010 and December 2012. Maxillofacial CT was used as the criterion standard for evaluating patients with maxillofacial fractures. The CT images were evaluated by using an electronic picture archiving and communications system and interpreted independently by 2 radiologists. The maxillofacial CT images revealed mandibular fractures in 167 of the patients and isolated tympanic plate fractures in 35 of these 167 patients. Four patients (11%) had a bilateral tympanic plate fracture, and 31 patients (89%) had unilateral tympanic plate fracture. Of all the tympanic plate fractures, 19 (54%) were on the right side and 16 (46%) were on the left side (P > .05). In our results, a significant correlation between the presence of a right-sided tympanic plate fracture and fracture of the ipsilateral condylar process was found (P = .036). However, a statistically significant difference between the presence of a tympanic plate fracture and other mandible fractures, additional soft-tissue findings, or the number of fractures was not determined (P > .05). Sex had no impact on the presence of tympanic plate fracture (P > .05). The frequency of isolated tympanic plate fractures in maxillofacial trauma is low, but it is an important anatomic location. Condyle fractures are significantly associated with isolated tympanic plate fractures. The presence of these injuries should raise suspicion of a concomitant isolated tympanic plate fracture. Copyright © 2014 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Pediatric fractures during skateboarding, roller skating, and scooter riding.

PubMed

Zalavras, Charalampos; Nikolopoulou, Georgia; Essin, Daniel; Manjra, Nahid; Zionts, Lewis E

2005-04-01

Skateboarding, roller skating, and scooter riding are popular recreational and sporting activities for children and adolescents but can be associated with skeletal injury. The purpose of this study is to describe the frequency and characteristics of fractures resulting from these activities. Fractures from skateboarding, roller skating, and scooter riding compose a considerable proportion of pediatric musculoskeletal injuries. Case series; Level of evidence, 4. Demographic data and injury characteristics were analyzed for all patients who presented to the pediatric fracture clinic of the level I trauma center from January 2001 to May 2002 after sustaining fractures due to skateboarding, roller skating, and scooter riding. Among a total of 2371 fractures, the authors identified 325 fractures (13.7%) that occurred during one of these activities. There were 187 patients (mean age, 13 years; 95% male) who sustained 191 skateboard-related fractures, 64 patients (mean age, 10.8 years; 54% male) who sustained 65 fractures while roller skating, and 66 patients (mean age, 9.7 years; 64% male) who sustained 69 fractures while riding a scooter. The forearm was fractured most often, composing 48.2% of skate-boarding fractures, 63.1% of roller-skating fractures, and 50.7% of fractures due to scooter riding. Of the forearm fractures, 94% were located in the distal third. In the skateboarding group, 10 of 191 (5.2%) fractures were open injuries of the forearm, compared to 6 of 2046 (0.3%) fractures caused by other mechanisms of injury (significant odds ratio, 18.8). Skateboarding, roller-skating, and scooter-riding accidents result in a large proportion of pediatric fractures. An open fracture, especially of the forearm, was more likely to be caused by skateboarding than by other mechanisms of injury. Use of wrist and forearm protective equipment should be considered in all children who ride a skateboard.

Nano-scale zero valent iron transport in a variable aperture dolomite fracture and a glass fracture

NASA Astrophysics Data System (ADS)

Mondal, P.; Sleep, B. E.; Cui, Z.; Zhou, Z.

2014-12-01

Experiments and numerical simulations are being performed to understand the transport behavior of carboxymethyl cellulose polymer stabilized nano-scale zero valent iron (nZVI) in a variable aperture dolomite rock fracture and a variable aperture glass replica of a fractured slate. The rock fracture was prepared by artificially inducing a fracture in a dolomite block along a stylolite, and the glass fracture was prepared by creating molds with melted glass on two opposing sides of a fractured slate rock block. Both of the fractures were 0.28 m in length and 0.21 m in width. Equivalent hydraulic apertures are about 110 microns for the rock fracture and 250 microns for the glass replica fracture. Sodium bromide and lissamine green B (LGB) serve as conservative tracers in the rock fracture and glass replica fracture, respectively. A dark box set-up with a light source and digital camera is being used to visualize the LGB and CMC-nZVI movement in the glass fracture. Experiments are being performed to determine the effects of water specific discharge and CMC concentration on nZVI transport in the fractures. Transmission electron microscopy, dynamic light scattering, and UV-visual spectrophotometry were performed to determine the stability and characteristics of the CMC-nZVI mixture. The transport of bromide, LGB, CMC, and CMC-nZVI in both fractures is being evaluated through analysis of the effluent concentrations. Time-lapse images are also being captured for the glass fracture. Bromide, LGB, and CMC recoveries have exceeded 95% in both fractures. Significant channeling has been observed in the fractures for CMC transport due to viscous effects.

A novel classification of frontal bone fractures: The prognostic significance of vertical fracture trajectory and skull base extension.

PubMed

Garg, Ravi K; Afifi, Ahmed M; Gassner, Jennifer; Hartman, Michael J; Leverson, Glen; King, Timothy W; Bentz, Michael L; Gentry, Lindell R

2015-05-01

The broad spectrum of frontal bone fractures, including those with orbital and skull base extension, is poorly understood. We propose a novel classification scheme for frontal bone fractures. Maxillofacial CT scans of trauma patients were reviewed over a five year period, and frontal bone fractures were classified: Type 1: Frontal sinus fracture without vertical extension. Type 2: Vertical fracture through the orbit without frontal sinus involvement. Type 3: Vertical fracture through the frontal sinus without orbit involvement. Type 4: Vertical fracture through the frontal sinus and ipsilateral orbit. Type 5: Vertical fracture through the frontal sinus and contralateral or bilateral orbits. We also identified the depth of skull base extension, and performed a chart review to identify associated complications. 149 frontal bone fractures, including 51 non-vertical frontal sinus (Type 1, 34.2%) and 98 vertical (Types 2-5, 65.8%) fractures were identified. Vertical fractures penetrated the middle or posterior cranial fossa significantly more often than non-vertical fractures (62.2 v. 15.7%, p = 0.0001) and had a significantly higher mortality rate (18.4 v. 0%, p < 0.05). Vertical fractures with frontal sinus and orbital extension, and fractures that penetrated the middle or posterior cranial fossa had the strongest association with intracranial injuries, optic neuropathy, disability, and death (p < 0.05). Vertical frontal bone fractures carry a worse prognosis than frontal bone fractures without a vertical pattern. In addition, vertical fractures with extension into the frontal sinus and orbit, or with extension into the middle or posterior cranial fossa have the highest complication rate and mortality. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

The AO Pediatric Comprehensive Classification of Long Bone Fractures (PCCF).

PubMed

Joeris, Alexander; Lutz, Nicolas; Blumenthal, Andrea; Slongo, Theddy; Audigé, Laurent

2017-04-01

Background and purpose - To achieve a common understanding when dealing with long bone fractures in children, the AO Pediatric Comprehensive Classification of Long Bone Fractures (AO PCCF) was introduced in 2007. As part of its final validation, we present the most relevant fracture patterns in the lower extremities of a representative population of children classified according to the PCCF. Patients and methods - We included patients up to the age of 17 who were diagnosed with 1 or more long bone fractures between January 2009 and December 2011 at either of 2 tertiary care university hospitals in Switzerland. Patient charts were retrospectively reviewed. Results - More lower extremity fractures occurred in boys (62%, n = 341). Of 548 fractured long bones in the lower extremity, 25% involved the femur and 75% the lower leg. The older the patients, the more combined fractures of the tibia and fibula were sustained (adolescents: 50%, 61 of 123). Salter-Harris (SH) fracture patterns represented 66% of single epiphyseal fractures (83 of 126). Overall, 74 of the 83 SH patterns occurred in the distal epiphysis. Of all the metaphyseal fractures, 74 of 79 were classified as incomplete or complete. Complete oblique spiral fractures accounted for 57% of diaphyseal fractures (120 of 211). Of all fractures, 7% (40 of 548) were classified in the category "other", including 29 fractures that were identified as toddler's fractures. 5 combined lower leg fractures were reported in the proximal metaphysis, 40 in the diaphysis, 26 in the distal metaphysis, and 8 in the distal epiphysis. Interpretation - The PCCF allows classification of lower extremity fracture patterns in the clinical setting. Re-introduction of a specific code for toddler's fractures in the PCCF should be considered.

The AO Pediatric Comprehensive Classification of Long Bone Fractures (PCCF)

PubMed Central

Joeris, Alexander; Lutz, Nicolas; Blumenthal, Andrea; Slongo, Theddy; Audigé, Laurent

2017-01-01

Background and purpose To achieve a common understanding when dealing with long bone fractures in children, the AO Pediatric Comprehensive Classification of Long Bone Fractures (AO PCCF) was introduced in 2007. As part of its final validation, we present the most relevant fracture patterns in the lower extremities of a representative population of children classified according to the PCCF. Patients and methods We included patients up to the age of 17 who were diagnosed with 1 or more long bone fractures between January 2009 and December 2011 at either of 2 tertiary care university hospitals in Switzerland. Patient charts were retrospectively reviewed. Results More lower extremity fractures occurred in boys (62%, n = 341). Of 548 fractured long bones in the lower extremity, 25% involved the femur and 75% the lower leg. The older the patients, the more combined fractures of the tibia and fibula were sustained (adolescents: 50%, 61 of 123). Salter-Harris (SH) fracture patterns represented 66% of single epiphyseal fractures (83 of 126). Overall, 74 of the 83 SH patterns occurred in the distal epiphysis. Of all the metaphyseal fractures, 74 of 79 were classified as incomplete or complete. Complete oblique spiral fractures accounted for 57% of diaphyseal fractures (120 of 211). Of all fractures, 7% (40 of 548) were classified in the category "other", including 29 fractures that were identified as toddler’s fractures. 5 combined lower leg fractures were reported in the proximal metaphysis, 40 in the diaphysis, 26 in the distal metaphysis, and 8 in the distal epiphysis. Interpretation The PCCF allows classification of lower extremity fracture patterns in the clinical setting. Re-introduction of a specific code for toddler’s fractures in the PCCF should be considered. PMID:27882811

Fracture patterns at lava-ice contacts on Kokostick Butte, OR, and Mazama Ridge, Mount Rainier, WA: Implications for flow emplacement and cooling histories

NASA Astrophysics Data System (ADS)

Lodge, Robert W. D.; Lescinsky, David T.

2009-09-01

Cooling lava commonly develop polygonal joints that form equant hexagonal columns. Such fractures are formed by thermal contraction resulting in an isotropic tensional stress regime. However, certain linear cooling fracture patterns observed at some lava-ice contacts do not appear to fit the model for formation of cooling fractures and columns because of their preferred orientations. These fracture types include sheet-like (ladder-like rectangular fracture pattern), intermediate (pseudo-aligned individual column-bounding fractures), and pseudopillow (straight to arcuate fractures with perpendicular secondary fractures caused by water infiltration) fractures that form the edges of multiple columns along a single linear fracture. Despite the relatively common occurrence of these types of fractures at lava-ice contacts, their significance and mode of formation have not been fully explored. This study investigates the stress regimes responsible for producing these unique fractures and their significance for interpreting cooling histories at lava-ice contacts. Data was collected at Kokostick Butte dacite flow at South Sister, OR, and Mazama Ridge andesite flow at Mount Rainier, WA. Both of these lava flows have been interpreted as being emplaced into contact with ice and linear fracture types have been observed on their ice-contacted margins. Two different mechanisms are proposed for the formation of linear fracture networks. One possible mechanism for the formation of linear fracture patterns is marginal bulging. Melting of confining ice walls will create voids into which flowing lava can deform resulting in margin-parallel tension causing margin-perpendicular fractures. If viewed from the ice-wall, these fractures would be steeply dipping, linear fractures. Another possible mechanism for the formation of linear fracture types is gravitational settling. Pure shear during compression and settling can result in a tensional environment with similar consequences as marginal inflation. In addition to this, horizontally propagating cooling fractures will be directly influenced by viscous strain caused by the settling of the flow. This would cause preferential opening of fractures horizontally, resulting in vertically oriented fractures. It is important to note that the proposed model for the formation of linear fractures is dependent on contact with and confinement by glacial ice. The influence of flow or movement on cooling fracture patterns has not been extensively discussed in previous modeling of cooling fractures. Rapid cooling of lava by the interaction with water and ice will increase the ability to the capture and preserve perturbations in the stress regime.

Characterizing Fractures Across the Astronaut Corps: Preliminary Findings from Population-Level Analysis

NASA Technical Reports Server (NTRS)

Rossi, Meredith M.; Charvat, Jacqueline; Sibonga, Jean; Sieker, Jeremy

2017-01-01

Despite evidence of bone loss during spaceflight and operational countermeasures to mitigate this loss, the subsequent risk of fracture among astronauts is not known. The physiologic process of diminished bone density and bone recovery during or following spaceflight is multifactorial. Such factors as age, sex, fracture history, and others may combine to increase fracture risk among astronauts. As part of the 2016 Bone Research and Clinical Advisory Panel (RCAP), the authors analyzed data collected on 338 NASA astronauts to describe the demographics, bone-relevant characteristics, and fracture history of the astronaut population. The majority of the population are male (n=286, 84.6%), have flown at least one mission (n=306, 90.5%), and were between the ages of 30 and 49 at first mission (n=296, 96.7% of those with at least one mission). Of the 338 astronauts, 241 (71.3%) experienced a fracture over the course of their lifetime. One hundred and five (43.5%) of these 241 astronauts only experienced a fracture prior to being selected into the Astronaut Corps, whereas 53 (22.0%) only experienced a fracture after selection as an astronaut. An additional 80 astronauts (33.2%) had both pre- and post-selection fractures. The remaining 3 astronauts had a fracture of unknown date, which could not be categorized as pre- or post-selection. Among the 133 astronauts with at least one post-selection fracture, males comprised 90.2% (n=120) compared to 84.5% of the entire Corps, and females accounted for 9.8% (n=13) compared to 15.4% of the Corps. Ninety-seven of the 133 astronauts with post-selection fractures (72.9%) had one fracture event, 22 (16.5%) had two fractures, and 14 (10.5%) had three or more fractures. Some astronauts with multiple fractures suffered these in a single event, such as an automobile accident. The 133 astronauts with a post-selection fracture accounted for a total of 188 fracture events. One hundred and four (78.2%) of astronauts with post-selection fractures experienced those fractures following their first mission (mean 12.7 +/- 11.1 years following first mission; range 14.0 days - 50.6 years). Additional analyses are ongoing and include examination of fracture history, skeletal site, mechanism, and type of fracture, age at time of fracture, time from spaceflight to fracture, as well as multivariable analysis comparing fracture events to non-events. The results of such analyses may reveal trends in risk factors for fracture among the astronaut corps that have yet to be systematically described through a corps-wide approach.

Hydraulic Fracture Extending into Network in Shale: Reviewing Influence Factors and Their Mechanism

PubMed Central

Ren, Lan; Zhao, Jinzhou; Hu, Yongquan

2014-01-01

Hydraulic fracture in shale reservoir presents complex network propagation, which has essential difference with traditional plane biwing fracture at forming mechanism. Based on the research results of experiments, field fracturing practice, theory analysis, and numerical simulation, the influence factors and their mechanism of hydraulic fracture extending into network in shale have been systematically analyzed and discussed. Research results show that the fracture propagation in shale reservoir is influenced by the geological and the engineering factors, which includes rock mineral composition, rock mechanical properties, horizontal stress field, natural fractures, treating net pressure, fracturing fluid viscosity, and fracturing scale. This study has important theoretical value and practical significance to understand fracture network propagation mechanism in shale reservoir and contributes to improving the science and efficiency of shale reservoir fracturing design. PMID:25032240

Prevalence and Cost of Subsequent Fractures Among U.S. Patients with an Incident Fracture.

PubMed

Weaver, Jessica; Sajjan, Shiva; Lewiecki, E Michael; Harris, Steven T; Marvos, Panagiotis

2017-04-01

The prevalence and cost of subsequent fractures among patients with an incident fracture are not well defined. To assess the prevalence of, and costs associated with, subsequent fractures in the year after an incident fracture. This was a retrospective claims database analysis using data from Humana Medicare Advantage claims (Medicare group) and Optum Insight Clinformatics Data Mart commercial claims (commercial group). Patients included in the study had a claim for a qualifying fracture occurring between January 2008 and December 2013 (index fracture), were continuously enrolled in the health plan for ≥ 1 year before and after the index fracture, and were aged ≥ 65 years in the Medicare group or ≥ 50 years in the commercial group at the time of the index fracture. Subsequent fractures were identified by ICD-9-CM codes and were defined as the second fracture occurring ≥ 3 to ≤ 12 months after the index fracture (≥ 6 to ≤ 12 months for fractures at the same site as the index fracture). Rates of subsequent fractures were calculated as the number of patients who had a subsequent fracture divided by the total sample size. After propensity matching of demographic and clinical variables, we determined the total medical and pharmacy costs accrued within 1 year of the index fracture by patients with and without a subsequent fracture. Health care costs were compared between patients with and without a subsequent fracture using McNemar's test. A total of 45,603 patients were included in the Medicare group, and 54,145 patients were included in the commercial group. In the Medicare group, 7,604 (16.7%) patients experienced a subsequent fracture. The proportion of patients with a subsequent fracture was highest among patients with multiple index fractures (26.2%, n = 905), followed by those with hip (25.5%, n = 1,280) and vertebral (20.2%, n = 1,908) index fractures. In the commercial group, 6,256 (11.6%) patients experienced a subsequent fracture. The proportion of patients with a subsequent fracture paralleled those observed in the Medicare group: 24.5% (n = 808) in patients with multiple index fractures, 22.0% (n = 525) in those with hip fracture, and 14.5% (n = 841) in those with vertebral fracture. For vertebral, hip, and nonhip nonvertebral fractures, subsequent fractures were most frequently of the same type as the index fracture. The mean total health care cost (sum of medical and pharmacy costs) in the year following the incident fracture for the Medicare group was $27,844 and differed significantly between patients with and without a subsequent fracture ($34,897 vs. $20,790; P < 0.001). The mean total health care cost in the year following the incident fracture for the commercial group was $29,316 and also differed significantly between patients with and without a subsequent fracture ($39,501 vs. $19,131; P < 0.001). Among patients with an incident fracture, those who experienced a subsequent fracture in the following year had significantly higher health care costs than those who did not. A subsequent fracture is most likely to be of the same type as the initial fracture. This study was funded by Merck & Co. Other than through the employer relationships disclosed here, Merck & Co did not have a role in the study design, data collection, interpretation of the data, in writing of the manuscript, or in the decision to submit the manuscript for publication. Weaver and Marvos are employees of Merck & Co. Sajjan was an employee of Merck & Co. and owned stock in the company at the time of the study. Lewiecki has received consulting and/or speaker honoraria from Merck, AbbVie, AgNovos Healthcare, Alexion Pharmaceuticals, Amgen, Eli Lilly and Company, Radius Health, Shire, and TheraNova. Lewiecki has received research grant support from Merck, Amgen, and Eli Lilly and Company and serves as a board member for the National Osteoporosis Foundation, the International Society for Clinical Densitometry, and the Osteoporosis Foundation of New Mexico. Harris has received consulting honoraria from Merck, Alexion Pharmaceuticals, Amgen, Eli Lilly and Company, Gilead Sciences, Primus Pharmaceuticals, and Radius Health. Study concept and design were contributed by Weave and Sajjan. Lewiecki collected the data, and data interpretation was performed by all the authors. The manuscript was written and revised by Weaver, Lewiecki, and Harris.

Microscopic Characterization of Tensile and Shear Fracturing in Progressive Failure in Marble

NASA Astrophysics Data System (ADS)

Cheng, Yi; Wong, Louis Ngai Yuen

2018-01-01

Compression-induced tensile and shear fractures were reported to be the two fundamental fracture types in rock fracturing tests. This study investigates such tensile and shear fracturing process in marble specimens containing two different flaw configurations. Observations first reveal that the development of a tensile fracture is distinct from shear fracture with respect to their nucleation, propagation, and eventual formation in macroscale. Second, transgranular cracks and grain-scale spallings become increasingly abundant in shear fractures as loading increases, which is almost not observed in tensile fractures. Third, one or some dominant extensional microcracks are commonly observed in the center of tensile fractures, while such development of microcracks is almost absent in shear fractures. Microcracks are generally of a length comparable to grain size and distribute uniformly within the damage zone of the shear fracture. Fourth, the width of densely damaged zone in the shear fracture is nearly 10 times of that in the tensile fracture. Quantitative measurement on microcrack density suggests that (1) microcrack density in tensile and shear fractures display distinct characteristics with increasing loading, (2) transgranular crack density in the shear fracture decreases logarithmically with the distance away from the shear fracture center, and (3) whatever the fracture type, the anisotropy can only be observed for transgranular cracks with a large density, which partially explains why microcrack anisotropy usually tends to be unobvious until approaching peak stress in specimens undergoing brittle failure. Microcracking characteristics observed in this work likely shed light to some phenomena and conclusions generalized in seismological studies.

An integrated structural and geochemical study of fracture aperture growth in the Campito Formation of eastern California

NASA Astrophysics Data System (ADS)

Doungkaew, N.; Eichhubl, P.

2015-12-01

Processes of fracture formation control flow of fluid in the subsurface and the mechanical properties of the brittle crust. Understanding of fundamental fracture growth mechanisms is essential for understanding fracture formation and cementation in chemically reactive systems with implications for seismic and aseismic fault and fracture processes, migration of hydrocarbons, long-term CO2 storage, and geothermal energy production. A recent study on crack-seal veins in deeply buried sandstone of east Texas provided evidence for non-linear fracture growth, which is indicated by non-elliptical kinematic fracture aperture profiles. We hypothesize that similar non-linear fracture growth also occurs in other geologic settings, including under higher temperature where solution-precipitation reactions are kinetically favored. To test this hypothesis, we investigate processes of fracture growth in quartzitic sandstone of the Campito Formation, eastern California, by combining field structural observations, thin section petrography, and fluid inclusion microthermometry. Fracture aperture profile measurements of cemented opening-mode fractures show both elliptical and non-elliptical kinematic aperture profiles. In general, fractures that contain fibrous crack-seal cement have elliptical aperture profiles. Fractures filled with blocky cement have linear aperture profiles. Elliptical fracture aperture profiles are consistent with linear-elastic or plastic fracture mechanics. Linear aperture profiles may reflect aperture growth controlled by solution-precipitation creep, with the aperture distribution controlled by solution-precipitation kinetics. We hypothesize that synkinematic crack-seal cement preserves the elliptical aperture profiles of elastic fracture opening increments. Blocky cement, on the other hand, may form postkinematically relative to fracture opening, with fracture opening accommodated by continuous solution-precipitation creep.

Spontaneous breathing during lung-protective ventilation in an experimental acute lung injury model: high transpulmonary pressure associated with strong spontaneous breathing effort may worsen lung injury.

PubMed

Yoshida, Takeshi; Uchiyama, Akinori; Matsuura, Nariaki; Mashimo, Takashi; Fujino, Yuji

2012-05-01

We investigated whether potentially injurious transpulmonary pressure could be generated by strong spontaneous breathing and exacerbate lung injury even when plateau pressure is limited to <30 cm H2O. Prospective, randomized, animal study. University animal research laboratory. Thirty-two New Zealand White rabbits. Lavage-injured rabbits were randomly allocated to four groups to receive low or moderate tidal volume ventilation, each combined with weak or strong spontaneous breathing effort. Inspiratory pressure for low tidal volume ventilation was set at 10 cm H2O and tidal volume at 6 mL/kg. For moderate tidal volume ventilation, the values were 20 cm H2O and 7-9 mL/kg. The groups were: low tidal volume ventilation+spontaneous breathingweak, low tidal volume ventilation+spontaneous breathingstrong, moderate tidal volume ventilation+spontaneous breathingweak, and moderate tidal volume ventilation+spontaneous breathingstrong. Each group had the same settings for positive end-expiratory pressure of 8 cm H2O. Respiratory variables were measured every 60 mins. Distribution of lung aeration and alveolar collapse were histologically evaluated. Low tidal volume ventilation+spontaneous breathingstrong showed the most favorable oxygenation and compliance of respiratory system, and the best lung aeration. By contrast, in moderate tidal volume ventilation+spontaneous breathingstrong, the greatest atelectasis with numerous neutrophils was observed. While we applied settings to maintain plateau pressure at <30 cm H2O in all groups, in moderate tidal volume ventilation+spontaneous breathingstrong, transpulmonary pressure rose >33 cm H2O. Both minute ventilation and respiratory rate were higher in the strong spontaneous breathing groups. Even when plateau pressure is limited to <30 cm H2O, combined with increased respiratory rate and tidal volume, high transpulmonary pressure generated by strong spontaneous breathing effort can worsen lung injury. When spontaneous breathing is preserved during mechanical ventilation, transpulmonary pressure and tidal volume should be strictly controlled to prevent further lung injury.

Rib fractures predict incident limb fractures: results from the European prospective osteoporosis study.

PubMed

Ismail, A A; Silman, A J; Reeve, J; Kaptoge, S; O'Neill, T W

2006-01-01

Population studies suggest that rib fractures are associated with a reduction in bone mass. While much is known about the predictive risk of hip, spine and distal forearm fracture on the risk of future fracture, little is known about the impact of rib fracture. The aim of this study was to determine whether a recalled history of rib fracture was associated with an increased risk of future limb fracture. Men and women aged 50 years and over were recruited from population registers in 31 European centres for participation in a screening survey of osteoporosis (European Prospective Osteoporosis Study). Subjects were invited to complete an interviewer-administered questionnaire that included questions about previous fractures including rib fracture, the age of their first fracture and also the level of trauma. Lateral spine radiographs were performed and the presence of vertebral deformity was determined morphometrically. Following the baseline survey, subjects were followed prospectively by annual postal questionnaire to determine the occurrence of clinical fractures. The subjects included 6,344 men, with a mean age of 64.2 years, and 6,788 women, with a mean age of 63.6 years, who were followed for a median of 3 years (range 0.4-5.9 years), of whom 135 men (2.3%) and 101 women (1.6%) reported a previous low trauma rib fracture. In total, 138 men and 391 women sustained a limb fracture during follow-up. In women, after age adjustment, those with a recalled history of low trauma rib fracture had an increased risk of sustaining 'any' limb fracture [relative hazard (RH)=2.3; 95% CI 1.3, 4.0]. When stratified by fracture type the predictive risk was more marked for hip (RH=7.7; 95% CI 2.3, 25.9) and humerus fracture (RH=4.5; 95% CI 1.4, 14.6) than other sites (RH=1.6; 95% CI 0.6, 4.3). Additional adjustment for prevalent vertebral deformity and previous (non-rib) low trauma fractures at other sites slightly reduced the strength of the association between rib fracture and subsequent limb fracture. In men, after age adjustment, there was a small though non-significant association between recalled history of rib fracture and future limb fracture. Our data highlight the importance of rib fracture as a marker of bone fragility in women.

Consequences of Fluid Lag in Three-Dimensional Hydraulic Fractures

NASA Astrophysics Data System (ADS)

Advani (Deceased), S. H.; Lee, T. S.; Dean, R. H.; Pak, C. K.; Avasthi, J. M.

1997-04-01

Research investigations on three-dimensional (3-D) rectangular hydraulic fracture configurations with varying degrees of fluid lag are reported. This paper demonstrates that a 3-D fracture model coupled with fluid lag (a small region of reduced pressure) at the fracture tip can predict very large excess pressure measurements for hydraulic fracture processes. Predictions of fracture propagation based on critical stress intensity factors are extremely sensitive to the pressure profile at the tip of a propagating fracture. This strong sensitivity to the pressure profile at the tip of a hydraulic fracture is more strongly pronounced in 3-D models versus 2-D models because 3-D fractures are clamped at the top and bottom, and pressures in the 3-D fractures that are far removed from the fracture tip have little effect on the stress intensity factor at the fracture tip. This rationale for the excess pressure mechanism is in marked contrast to the crack tip process damage zone assumptions and attendant high rock fracture toughness value hypotheses advanced in the literature. A comparison with field data is presented to illustrate the proposed fracture fluid pressure sensitivity phenomenon. This paper does not attempt to calculate the length of the fluid lag region in a propagating fracture but instead attempts to show that the pressure profile at the tip of the propagating fracture plays a major role in fracture propagation, and this role is magnified in 3-D models. Int. J. Numer. Anal. Meth. Geomech., vol. 21, 229-240 (1997).

[Study of incidence of osteoporotic fractures in a cohort of individuals older than 50 years from Asturias, Spain, after a 6 year follow-up period].

PubMed

Naves Díaz, M; Díaz López, J B; Gómez Alonso, C; Altadill Arregui, A; Rodríguez Rebollar, A; Cannata Andía, J B

2000-11-18

The present work, performed as follow-up of the prevalence study of vertebral fractures (EVOS Study), evaluates in a 6 year period the incidence of vertebral fractures and other osteoporotic fractures in Oviedo (Asturias, Spain) in people older than 50 years. The study was performed in a cohort from the Oviedo's local registry in 1986. 624 men and women were followed by 3 postal questionnaires. The first questionnaire referred to the history of falls and fractures that happened during the follow-up period performed. Between the 2nd and 3rd follow-up subjects were invited to repeat the X-rays previously performed in the initial study. The incidence of osteoporotic fractures was higher in women than in men. In both sexes, vertebral fracture was the one which reached the highest incidence. Compared with men, Colles' fracture in women occurred earlier, with 5 times higher incidence. The incidence of hip fracture was twice higher in women than in men. A prevalent vertebral fractures increased until 5 times the incidence of vertebral and hip fracture. Among the osteoporotic fractures, vertebral fracture had a highest incidence values in both sexes. Although vertebral and hip fractures were twice incident in women compared with men, the incidence of Colles fracture was five times higher in women. A pre-existing vertebral fracture is an important risk factor to develop a new vertebral or hip fracture.

Integration of fracturing dynamics and pressure transient analysis for hydraulic fracture evaluation

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

Arihara, N.; Abbaszadeh, M.; Wright, C.A.

This paper presents pre- and post-fracture pressure transient analysis, combined with net fracture pressure interpretation, for a well in a naturally fractured geothermal reservoir. Integrated analysis was performed to achieve a consistent interpretation of the created fracture geometry, propagation, conductivity, shrinkage, reservoir flow behavior, and formation permeability characteristics. The interpreted data includes two-rate pre-frac injection tests, step-rate injection tests, a series of pressure falloff tests, and the net fracturing pressure from a massive fracture treatment. Pressure transient analyses were performed utilizing advanced well test interpretation techniques and a thermal reservoir simulator with fracture propagation option. Hydraulic fracture propagation analysis wasmore » also performed Milt a generalized 3-D dynamic fracture growth model simulator. Three major conclusions resulted from the combined analysis: (1) that an increasing number of hydraulic fractures were being simultaneously propagated during the fracture treatment. (2) that the reservoir behaved as a composite reservoir Keith the outer region permeability being greater than the permeability of the region immediately surrounding the wellbore, and (3) that the created fractures extended into the outer region during the fracture treatment but retreated to the inner region several days after stimulation had ceased. These conclusions were apparent from independent pressure transient analysis and from independent hydraulic fracture propagation analysis. Integrated interpretation, however, increased the confidence in these conclusions and greatly aided the quantification of the created hydraulic fracture geometry and characterization of the reservoir permeability.« less

Second hip fractures at Chiang Mai University Hospital.

PubMed

Wongtriratanachai, Prasit; Chiewchantanakit, Siripong; Vaseenon, Tanawat; Rojanasthien, Sattaya; Leerapun, Taninnit

2015-02-01

Hip fractures are a major public health problem. Patients who have suffered a hip fracture have an increased risk of a subsequent hip fracture. This study examines the incidence ofsecondhip fractures and attempts to identify underlying risk factors. To examine the incidence ofsecond hip fractures in osteoporotic patients at Chiang Mai University Hospital and to identify risk factors related to second hip fractures. A retrospective review was conducted of all low-energy mechanism hip fracture patients admitted during 2008 and 2009. Analysis of second hip fractures was conducted using survival analysis and logistic regression analysis. A total of 191 patients were observed for 391.68 person-years (mean 2.05 person-years per patient). Among that group, nine second hip fractures were identified, an overall incidence rate of 0.023 second fractures per person-year. Second hip fractures tended to occur within the first year following an initial hip fracture. There were no significant differences related to either gender or comorbid medical conditions. Logistic regression analysis revealed that increased risk of a second hip fracture was associated with age (highest between 80 to 89 years) and patients who were not treated for osteoporosis following their initial fracture. The incidence of second hip fractures at Chiang Mai University Hospital was 0.023 per person-year Careful follow-up of older patients, especially those over 80, and treatment ofosteoporosis with bisphosphonate plus vitamin D and calcium supplements was correlated with a reduction in the incidence of second hip fractures.

Geographic and ethnic disparities in osteoporotic fractures.

PubMed

Cauley, Jane A; Chalhoub, Didier; Kassem, Ahmed M; Fuleihan, Ghada El-Hajj

2014-06-01

Osteoporotic fractures are a major worldwide epidemic. Here, we review global variability, ethnic differences and secular changes in osteoporotic fractures. Worldwide, age-standardized incidence rates of hip fracture vary >200-fold in women and >140-fold in men when comparing the country in which incidence rates are the highest with that in which they are the lowest. Median age-standardized rates are highest in North America and Europe, followed by Asia, Middle East, Oceania, Latin America and Africa. Globally, rates of hip fracture are greater in women than in men, with an average ratio of ∼2:1. The incidence of radiographic vertebral fractures is much higher than that of hip fractures, whereas the incidence rates of clinical vertebral fractures mirror hip fracture rates in most countries. Methodological challenges of defining and ascertaining vertebral fractures limit the interpretation of these data. Secular declines in hip fracture rates have been reported in populations from North America, Europe and Oceania. These declines are especially notable in women, suggesting that reproductive factors might contribute to this reduction. By contrast, hip fracture rates are increasing in parts of Asia and Latin America. Global indicators of health, education and socioeconomic status are positively correlated with fracture rates suggesting that lifestyles in developed countries might contribute to hip fracture. Improvements in fracture assessment, in particular for nonhip fractures, and identification of factors that contribute to this variability might substantially influence our understanding of osteoporotic fracture aetiology and provide new avenues for prevention.

Prior nonhip limb fracture predicts subsequent hip fracture in institutionalized elderly people.

PubMed

Nakamura, K; Takahashi, S; Oyama, M; Oshiki, R; Kobayashi, R; Saito, T; Yoshizawa, Y; Tsuchiya, Y

2010-08-01

This 1-year cohort study of nursing home residents revealed that historical fractures of upper limbs or nonhip lower limbs were associated with hip fracture (hazard ratio = 2.14), independent of activities of daily living (ADL), mobility, dementia, weight, and type of nursing home. Prior nonhip fractures are useful for predicting of hip fracture in institutional settings. The aim of this study was to evaluate the utility of fracture history for the prediction of hip fracture in nursing home residents. This was a cohort study with a 1-year follow-up. Subjects were 8,905 residents of nursing homes in Niigata, Japan (mean age, 84.3 years). Fracture histories were obtained from nursing home medical records. ADL levels were assessed by caregivers. Hip fracture diagnosis was based on hospital medical records. Subjects had fracture histories of upper limbs (5.0%), hip (14.0%), and nonhip lower limbs (4.6%). Among historical single fractures, only prior nonhip lower limbs significantly predicted subsequent fracture (adjusted hazard ratio, 2.43; 95% confidence interval (CI), 1.30-4.57). The stepwise method selected the best model, in which a combined historical fracture at upper limbs or nonhip lower limbs (adjusted hazard ratio, 2.14; 95% CI, 1.30-3.52), dependence, ADL levels, mobility, dementia, weight, and type of nursing home independently predicted subsequent hip fracture. A fracture history at upper or nonhip lower limbs, in combination with other known risk factors, is useful for the prediction of future hip fracture in institutional settings.

Fluid Production Induced Stress Analysis Surrounding an Elliptic Fracture

NASA Astrophysics Data System (ADS)

Pandit, Harshad Rajendra

Hydraulic fracturing is an effective technique used in well stimulation to increase petroleum well production. A combination of multi-stage hydraulic fracturing and horizontal drilling has led to the recent boom in shale gas production which has changed the energy landscape of North America. During the fracking process, highly pressurized mixture of water and proppants (sand and chemicals) is injected into to a crack, which fractures the surrounding rock structure and proppants help in keeping the fracture open. Over a longer period, however, these fractures tend to close due to the difference between the compressive stress exerted by the reservoir on the fracture and the fluid pressure inside the fracture. During production, fluid pressure inside the fracture is reduced further which can accelerate the closure of a fracture. In this thesis, we study the stress distribution around a hydraulic fracture caused by fluid production. It is shown that fluid flow can induce a very high hoop stress near the fracture tip. As the pressure gradient increases stress concentration increases. If a fracture is very thin, the flow induced stress along the fracture decreases, but the stress concentration at the fracture tip increases and become unbounded for an infinitely thin fracture. The result from the present study can be used for studying the fracture closure problem, and ultimately this in turn can lead to the development of better proppants so that prolific well production can be sustained for a long period of time.

The influence of spontaneous activity on stimulus processing in primary visual cortex.

PubMed

Schölvinck, M L; Friston, K J; Rees, G

2012-02-01

Spontaneous activity in the resting human brain has been studied extensively; however, how such activity affects the local processing of a sensory stimulus is relatively unknown. Here, we examined the impact of spontaneous activity in primary visual cortex on neuronal and behavioural responses to a simple visual stimulus, using functional MRI. Stimulus-evoked responses remained essentially unchanged by spontaneous fluctuations, combining with them in a largely linear fashion (i.e., with little evidence for an interaction). However, interactions between spontaneous fluctuations and stimulus-evoked responses were evident behaviourally; high levels of spontaneous activity tended to be associated with increased stimulus detection at perceptual threshold. Our results extend those found in studies of spontaneous fluctuations in motor cortex and higher order visual areas, and suggest a fundamental role for spontaneous activity in stimulus processing. Copyright © 2011. Published by Elsevier Inc.

Occupational exposures among nurses and risk of spontaneous abortion.

PubMed

Lawson, Christina C; Rocheleau, Carissa M; Whelan, Elizabeth A; Lividoti Hibert, Eileen N; Grajewski, Barbara; Spiegelman, Donna; Rich-Edwards, Janet W

2012-04-01

We investigated self-reported occupational exposure to antineoplastic drugs, anesthetic gases, antiviral drugs, sterilizing agents (disinfectants), and X-rays and the risk of spontaneous abortion in US nurses. Pregnancy outcome and occupational exposures were collected retrospectively from 8461 participants of the Nurses' Health Study II. Of these, 7482 were eligible for analysis using logistic regression. Participants reported 6707 live births, and 775 (10%) spontaneous abortions (<20 weeks). After adjusting for age, parity, shift work, and hours worked, antineoplastic drug exposure was associated with a 2-fold increased risk of spontaneous abortion, particularly with early spontaneous abortion before the 12th week, and 3.5-fold increased risk among nulliparous women. Exposure to sterilizing agents was associated with a 2-fold increased risk of late spontaneous abortion (12-20 weeks), but not with early spontaneous abortion. This study suggests that certain occupational exposures common to nurses are related to risks of spontaneous abortion. Published by Mosby, Inc.

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.

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

Prior ankle fractures in postmenopausal women are associated with low areal bone mineral density and bone microstructure alterations.

PubMed

Biver, E; Durosier, C; Chevalley, T; Herrmann, F R; Ferrari, S; Rizzoli, R

2015-08-01

In a cross-sectional analysis in postmenopausal women, prior ankle fractures were associated with lower areal bone mineral density (BMD) and trabecular bone alterations compared to no fracture history. Compared to women with forearm fractures, microstructure alterations were of lower magnitude. These data suggest that ankle fractures are another manifestation of bone fragility. Whether ankle fractures represent fragility fractures associated with low areal bone mineral density (aBMD) and volumetric bone mineral density (vBMD) and/or bone microstructure alterations remains unclear, in contrast to the well-recognised association between forearm fractures and osteoporosis. The objective of this study was to investigate aBMD, vBMD and bone microstructure in postmenopausal women with prior ankle fracture in adulthood, compared with women without prior fracture or with women with prior forearm fractures, considered as typically of osteoporotic origin. In a cross-sectional analysis in the Geneva Retirees Cohort study, 63 women with ankle fracture and 59 with forearm fracture were compared to 433 women without fracture (mean age, 65 ± 1 years). aBMD was measured by dual-energy X-ray absorptiometry; distal radius and tibia vBMD and bone microstructure were measured by high-resolution peripheral quantitative computed tomography. Compared with women without fracture, those with ankle fractures had lower aBMD, radius vBMD (-7.9%), trabecular density (-10.7%), number (-7.3%) and thickness (-4.6%) and higher trabecular spacing (+14.5%) (P < 0.05 for all). Tibia trabecular variables were also altered. For 1 standard deviation decrease in total hip aBMD or radius trabecular density, odds ratios for ankle fractures were 2.2 and 1.6, respectively, vs 2.2 and 2.7 for forearm fracture, respectively (P ≤ 0.001 for all). Compared to women with forearm fractures, those with ankle fractures had similar spine and hip aBMD, but microstructure alterations of lower magnitude. Women with ankle fractures have lower aBMD and vBMD and trabecular bone alterations, suggesting that ankle fractures are another manifestation of bone fragility.

Thoracic kyphosis and rate of incident vertebral fractures: the Fracture Intervention Trial.

PubMed

Katzman, W B; Vittinghoff, E; Kado, D M; Lane, N E; Ensrud, K E; Shipp, K

2016-03-01

Biomechanical analyses support the theory that thoracic spine hyperkyphosis may increase risk of new vertebral fractures. While greater kyphosis was associated with an increased rate of incident vertebral fractures, our analysis does not show an independent association of kyphosis on incident fracture, after adjustment for prevalent vertebral fracture. Excessive kyphosis may still be a clinical marker for prevalent vertebral fracture. Biomechanical analyses suggest hyperkyphosis may increase risk of incident vertebral fracture by increasing the load on vertebral bodies during daily activities. We propose to assess the association of kyphosis with incident radiographic vertebral fracture. We used data from the Fracture Intervention Trial among 3038 women 55-81 years of age with low bone mineral density (BMD). Baseline kyphosis angle was measured using a Debrunner kyphometer. Vertebral fractures were assessed at baseline and follow-up from lateral radiographs of the thoracic and lumbar spine. We used Poisson models to estimate the independent association of kyphosis with incident fracture, controlling for age and femoral neck BMD. Mean baseline kyphosis was 48° (SD = 12) (range 7-83). At baseline, 962 (32%) participants had a prevalent fracture. There were 221 incident fractures over a median of 4 years. At baseline, prevalent fracture was associated with 3.7° greater average kyphosis (95% CI 2.8-4.6, p < 0.0005), adjusting for age and femoral neck BMD. Before adjusting for prevalent fracture, each 10° greater kyphosis was associated with 22% increase (95% CI 8-38%, p = 0.001) in annualized rate of new radiographic vertebral fracture, adjusting for age and femoral neck BMD. After additional adjustment for prevalent fracture, estimated increased annualized rate was attenuated and no longer significant, 8% per 10° kyphosis (95% CI -4 to 22%, p = 0.18). While greater kyphosis increased the rate of incident vertebral fractures, our analysis does not show an independent association of kyphosis on incident fracture, after adjustment for prevalent vertebral fracture. Excessive kyphosis may still be a clinical marker for prevalent vertebral fracture.

Thoracic kyphosis and rate of incident vertebral fractures: the Fracture Intervention Trial

PubMed Central

Vittinghoff, E.; Kado, D. M.; Lane, N. E.; Ensrud, K. E.; Shipp, K.

2016-01-01

Summary Biomechanical analyses support the theory that thoracic spine hyperkyphosis may increase risk of new vertebral fractures. While greater kyphosis was associated with an increased rate of incident vertebral fractures, our analysis does not show an independent association of kyphosis on incident fracture, after adjustment for prevalent vertebral fracture. Excessive kyphosis may still be a clinical marker for prevalent vertebral fracture. Introduction Biomechanical analyses suggest hyperkyphosis may increase risk of incident vertebral fracture by increasing the load on vertebral bodies during daily activities. We propose to assess the association of kyphosis with incident radiographic vertebral fracture. Methods We used data from the Fracture Intervention Trial among 3038 women 55–81 years of age with low bone mineral density (BMD). Baseline kyphosis angle was measured using a Debrunner kyphometer. Vertebral fractures were assessed at baseline and follow-up from lateral radiographs of the thoracic and lumbar spine. We used Poisson models to estimate the independent association of kyphosis with incident fracture, controlling for age and femoral neck BMD. Results Mean baseline kyphosis was 48° (SD = 12) (range 7–83). At baseline, 962 (32 %) participants had a prevalent fracture. There were 221 incident fractures over a median of 4 years. At baseline, prevalent fracture was associated with 3.7° greater average kyphosis (95 % CI 2.8–4.6, p < 0.0005), adjusting for age and femoral neck BMD. Before adjusting for prevalent fracture, each 10° greater kyphosis was associated with 22 % increase (95 % CI 8–38 %, p = 0.001) in annualized rate of new radiographic vertebral fracture, adjusting for age and femoral neck BMD. After additional adjustment for prevalent fracture, estimated increased annualized rate was attenuated and no longer significant, 8 % per 10° kyphosis (95 % CI −4 to 22 %, p = 0.18). Conclusions While greater kyphosis increased the rate of incident vertebral fractures, our analysis does not show an independent association of kyphosis on incident fracture, after adjustment for prevalent vertebral fracture. Excessive kyphosis may still be a clinical marker for prevalent vertebral fracture. PMID:26782685

A Generic analytical solution for modelling pumping tests in wells intersecting fractures

NASA Astrophysics Data System (ADS)

Dewandel, Benoît; Lanini, Sandra; Lachassagne, Patrick; Maréchal, Jean-Christophe

2018-04-01

The behaviour of transient flow due to pumping in fractured rocks has been studied for at least the past 80 years. Analytical solutions were proposed for solving the issue of a well intersecting and pumping from one vertical, horizontal or inclined fracture in homogeneous aquifers, but their domain of application-even if covering various fracture geometries-was restricted to isotropic or anisotropic aquifers, whose potential boundaries had to be parallel or orthogonal to the fracture direction. The issue thus remains unsolved for many field cases. For example, a well intersecting and pumping a fracture in a multilayer or a dual-porosity aquifer, where intersected fractures are not necessarily parallel or orthogonal to aquifer boundaries, where several fractures with various orientations intersect the well, or the effect of pumping not only in fractures, but also in the aquifer through the screened interval of the well. Using a mathematical demonstration, we show that integrating the well-known Theis analytical solution (Theis, 1935) along the fracture axis is identical to the equally well-known analytical solution of Gringarten et al. (1974) for a uniform-flux fracture fully penetrating a homogeneous aquifer. This result implies that any existing line- or point-source solution can be used for implementing one or more discrete fractures that are intersected by the well. Several theoretical examples are presented and discussed: a single vertical fracture in a dual-porosity aquifer or in a multi-layer system (with a partially intersecting fracture); one and two inclined fractures in a leaky-aquifer system with pumping either only from the fracture(s), or also from the aquifer between fracture(s) in the screened interval of the well. For the cases with several pumping sources, analytical solutions of flowrate contribution from each individual source (fractures and well) are presented, and the drawdown behaviour according to the length of the pumped screened interval of the well is discussed. Other advantages of this proposed generic analytical solution are also given. The application of this solution to field data should provide additional field information on fracture geometry, as well as identifying the connectivity between the pumped fractures and other aquifers.

Developing a Fracture Model of the Granite Rocks Around the Research Tunnel at the Mizunami Underground Research Laboratory in Central Japan

NASA Astrophysics Data System (ADS)

Kalinina, E.; Hadgu, T.; Wang, Y.

2017-12-01

The Mizunami Underground Research Laboratory (MIU) is located in Tono area in Central Japan. It is operated by the Japan Atomic Energy Agency (JAEA) with the main purpose of providing scientific basis for the research and development of technologies needed for deep geological disposal of radioactive waste in fractured crystalline rocks. The current work is focused on the research and experiments in the tunnel located at 500 m depth. The data collected in the tunnel and exploratory boreholes were shared with the participants of the DEvelopment of COupled models and their VALidation against EXperiments (DECOVALEX), an international research and model comparison collaboration. This study describes the development of the fracture model representing granite rocks around the research tunnel. The model domain is 100x150x100m with the main experimental part of the tunnel, Closure Test Drift, located approximately in the center. The major input data were the fracture traces measured on the tunnel walls (total of 2,023 fractures), fractures observed in the horizontal borehole parallel to the tunnel, and the packer tests conducted in this borehole and one vertical borehole located within the modeling domain. 78 fractures (the ones with the inflow) in the tunnel were incorporated in the development of the fracture model. Fracture size was derived from the fracture trace analysis. It was shown that the fracture radius followed lognormal distributions. Fracture transmissivity was estimated from an analytical solution of inflow into the tunnel through an individual fracture and the total measured inflow into the tunnel. 16 fractures were incorporated in the model along the horizontal borehole. The packer test data in the different well intervals were used to estimate the range in fracture transmissivity. A relationship between the fracture transmissivity and fracture radius was developed. The fractures in the tunnel and borehole were used to derive fracture orientation and fracture intensity distributions. These distributions were used to generate stochastic fractures outside the tunnel and horizontal borehole. The fracture model was upscaled to an orthogonal continuum mesh with 1x1x1 m3 cell size using Oda's method.

The Effect of fluid buoyancy and fracture orientation on CaCO3 Formation in a Fracture

NASA Astrophysics Data System (ADS)

Xu, Z.; Li, Q.; Sheets, J.; Kneafsey, T. J.; Jun, Y. S.; Cole, D. R.; Pyrak-Nolte, L. J.

2016-12-01

Sealing fractures through mineral precipitation is a potential way for improving caprock integrity in subsurface reservoirs. We investigated the effect of buoyancy and fracture orientation on the amount and spatial distribution of calcium carbonate (CaCO3) precipitates in a fracture. To monitor mineral precipitation during reactive flow, transparent acrylic casts of an induced fracture in Austin chalk were used. To trigger CaCO3 precipitates, 1M CaCl2 with either 0.6M NaHCO3 solution (for surface adhering precipitation), or 0.3M Na2CO3 solution (for pore filling precipitation) were injected simultaneously into a saturated fracture. Experiments were performed with the fracture plane oriented either parallel or perpendicular to gravity. Acoustic wave transmission (compressional wave, 1 MHz) and optical imaging were used to monitor the sample prior to, during and after fluid injection. Complementary X-ray computed tomography was performed throughout the experiments on vertical fractures and post injection for the horizontal fractures. For the vertical fractures, the denser CaCl2 almost completely displaced the carbonate solution in the fracture and caused strong localization of the precipitates. The width of the precipitated region grew slowly over time. The horizontal fracture caused the less dense carbonate to flow over the CaCl2 solution thus resulting in more mixing and a more even distribution of precipitates throughout the fracture. The acoustic signatures depended on the type of precipitation that occurred. For pore filling experiments, the compressional wave amplitude increased by 5-20% and the velocity increased for both the vertical and horizontal fractures. However, the acoustic responses differed between the vertical and horizontal fractures for surface adhering experiments. Based on the acoustic response, surface adhering precipitation increased fracture specific stiffness more in the horizontal fracture than in the vertical fracture. The horizontal fracture enabled more mixing of the two solutions within the fracture than the vertical fracture. This work was supported by the Center for Nanoscale Controls on Geologic CO (NCGC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-AC02-05CH11231

Proximal femoral fractures.

PubMed

Webb, Lawrence X

2002-01-01

Fractures of the proximal femur include fractures of the head, neck, intertrochanteric, and subtrochanteric regions. Head fractures commonly accompany dislocations. Neck fractures and intertrochanteric fractures occur with greatest frequency in elderly patients with a low bone mineral density and are produced by low-energy mechanisms. Subtrochanteric fractures occur in a predominantly strong cortical osseous region which is exposed to large compressive stresses. Implants used to address these fractures must be able to accommodate significant loads while the fractures consolidate. Complications secondary to these injuries produce significant morbidity and include infection, nonunion, malunion, decubitus ulcers, fat emboli, deep venous thrombosis, pulmonary embolus, pneumonia, myocardial infarction, stroke, and death.

Theoretical Analysis of the Mechanism of Fracture Network Propagation with Stimulated Reservoir Volume (SRV) Fracturing in Tight Oil Reservoirs.

PubMed

Su, Yuliang; Ren, Long; Meng, Fankun; Xu, Chen; Wang, Wendong

2015-01-01

Stimulated reservoir volume (SRV) fracturing in tight oil reservoirs often induces complex fracture-network growth, which has a fundamentally different formation mechanism from traditional planar bi-winged fracturing. To reveal the mechanism of fracture network propagation, this paper employs a modified displacement discontinuity method (DDM), mechanical mechanism analysis and initiation and propagation criteria for the theoretical model of fracture network propagation and its derivation. A reasonable solution of the theoretical model for a tight oil reservoir is obtained and verified by a numerical discrete method. Through theoretical calculation and computer programming, the variation rules of formation stress fields, hydraulic fracture propagation patterns (FPP) and branch fracture propagation angles and pressures are analyzed. The results show that during the process of fracture propagation, the initial orientation of the principal stress deflects, and the stress fields at the fracture tips change dramatically in the region surrounding the fracture. Whether the ideal fracture network can be produced depends on the geological conditions and on the engineering treatments. This study has both theoretical significance and practical application value by contributing to a better understanding of fracture network propagation mechanisms in unconventional oil/gas reservoirs and to the improvement of the science and design efficiency of reservoir fracturing.

Antebrachial fractures in four captive polar bears (Ursus maritimus).

PubMed

Lin, Rebecca C; Engeli, Emmanuel; Prowten, Allan W; Erb, Hollis N; Ducharme, Norm G; Goodrich, Laurie R

2005-01-01

To identify common risk factors for antebrachial fractures of captive polar bears and to evaluate outcome after fracture repair. Retrospective study. Four captive polar bears. United States zoological collections were surveyed to determine the prevalence of fractures in captive polar bears. Medical records of captive polar bears that had antebrachial fractures were reviewed for signalment, history, physical and radiographic findings, fracture management, postoperative care, and outcome. Serum samples from healthy bears and bears with antebrachial fractures were assayed for 25-hydroxyvitamin D (25-OHD) concentrations. Nineteen fractures (12 polar bears) occurred from 1974 to 2002; 12 fractures involved the antebrachium. Management of 4 antebrachial fractures was reviewed; 3 were repaired by internal fixation and 1 by external coaptation. Fractures healed and bears were returned to exhibit on average 3 months postfracture. Of 11 serum samples assayed for 25-OHD concentrations, 6 were below normal, 1 was low normal and 4 were within normal reference intervals. The 7 bears with subnormal or low normal values were housed in 2 zoos. Subnormal vitamin D concentrations were identified in 2 of 3 bears with fractures. Fracture disease is not uncommon in captive polar bears. Additional research is necessary to explore the role of nutrition in polar bear fracture disease. Internal fixation of antebrachial fractures is feasible and reasonably well tolerated in captive polar bears.

Simulating Fragmentation and Fluid-Induced Fracture in Disordered Media Using Random Finite-Element Meshes

DOE PAGES

Bishop, Joseph E.; Martinez, Mario J.; Newell, Pania

2016-11-08

Fracture and fragmentation are extremely nonlinear multiscale processes in which microscale damage mechanisms emerge at the macroscale as new fracture surfaces. Numerous numerical methods have been developed for simulating fracture initiation, propagation, and coalescence. In this paper, we present a computational approach for modeling pervasive fracture in quasi-brittle materials based on random close-packed Voronoi tessellations. Each Voronoi cell is formulated as a polyhedral finite element containing an arbitrary number of vertices and faces. Fracture surfaces are allowed to nucleate only at the intercell faces. Cohesive softening tractions are applied to new fracture surfaces in order to model the energy dissipatedmore » during fracture growth. The randomly seeded Voronoi cells provide a regularized discrete random network for representing fracture surfaces. The potential crack paths within the random network are viewed as instances of realizable crack paths within the continuum material. Mesh convergence of fracture simulations is viewed in a weak, or distributional, sense. The explicit facet representation of fractures within this approach is advantageous for modeling contact on new fracture surfaces and fluid flow within the evolving fracture network. Finally, applications of interest include fracture and fragmentation in quasi-brittle materials and geomechanical applications such as hydraulic fracturing, engineered geothermal systems, compressed-air energy storage, and carbon sequestration.« less

Simulating Fragmentation and Fluid-Induced Fracture in Disordered Media Using Random Finite-Element Meshes

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

Bishop, Joseph E.; Martinez, Mario J.; Newell, Pania

Fracture and fragmentation are extremely nonlinear multiscale processes in which microscale damage mechanisms emerge at the macroscale as new fracture surfaces. Numerous numerical methods have been developed for simulating fracture initiation, propagation, and coalescence. In this paper, we present a computational approach for modeling pervasive fracture in quasi-brittle materials based on random close-packed Voronoi tessellations. Each Voronoi cell is formulated as a polyhedral finite element containing an arbitrary number of vertices and faces. Fracture surfaces are allowed to nucleate only at the intercell faces. Cohesive softening tractions are applied to new fracture surfaces in order to model the energy dissipatedmore » during fracture growth. The randomly seeded Voronoi cells provide a regularized discrete random network for representing fracture surfaces. The potential crack paths within the random network are viewed as instances of realizable crack paths within the continuum material. Mesh convergence of fracture simulations is viewed in a weak, or distributional, sense. The explicit facet representation of fractures within this approach is advantageous for modeling contact on new fracture surfaces and fluid flow within the evolving fracture network. Finally, applications of interest include fracture and fragmentation in quasi-brittle materials and geomechanical applications such as hydraulic fracturing, engineered geothermal systems, compressed-air energy storage, and carbon sequestration.« less

Theoretical Analysis of the Mechanism of Fracture Network Propagation with Stimulated Reservoir Volume (SRV) Fracturing in Tight Oil Reservoirs

PubMed Central

Su, Yuliang; Ren, Long; Meng, Fankun; Xu, Chen; Wang, Wendong

2015-01-01

Stimulated reservoir volume (SRV) fracturing in tight oil reservoirs often induces complex fracture-network growth, which has a fundamentally different formation mechanism from traditional planar bi-winged fracturing. To reveal the mechanism of fracture network propagation, this paper employs a modified displacement discontinuity method (DDM), mechanical mechanism analysis and initiation and propagation criteria for the theoretical model of fracture network propagation and its derivation. A reasonable solution of the theoretical model for a tight oil reservoir is obtained and verified by a numerical discrete method. Through theoretical calculation and computer programming, the variation rules of formation stress fields, hydraulic fracture propagation patterns (FPP) and branch fracture propagation angles and pressures are analyzed. The results show that during the process of fracture propagation, the initial orientation of the principal stress deflects, and the stress fields at the fracture tips change dramatically in the region surrounding the fracture. Whether the ideal fracture network can be produced depends on the geological conditions and on the engineering treatments. This study has both theoretical significance and practical application value by contributing to a better understanding of fracture network propagation mechanisms in unconventional oil/gas reservoirs and to the improvement of the science and design efficiency of reservoir fracturing. PMID:25966285

Sacral Fractures and Associated Injuries

PubMed Central

Kurd, Mark F.; Schroeder, Gregory D.; Kepler, Christopher K.; Krieg, James C.; Holstein, Jörg H.; Bellabarba, Carlo; Firoozabadi, Reza; Oner, F. Cumhur; Kandziora, Frank; Dvorak, Marcel F.; Kleweno, Conor P.; Vialle, Luiz R.; Rajasekaran, S.; Schnake, Klause J.; Vaccaro, Alexander R.

2017-01-01

Study Design: Literature review. Objective: The aim of this review is to describe the injuries associated with sacral fractures and to analyze their impact on patient outcome. Methods: A comprehensive narrative review of the literature was performed to identify the injuries associated with sacral fractures. Results: Sacral fractures are uncommon injuries that result from high-energy trauma, and that, due to their rarity, are frequently underdiagnosed and mistreated. Only 5% of sacral fractures occur in isolation. Injuries most often associated with sacral fractures include neurologic injuries (present in up to 50% of sacral fractures), pelvic ring disruptions, hip and lumbar spine fractures, active pelvic/ abdominal bleeding and the presence of an open fracture or significant soft tissue injury. Diagnosis of pelvic ring fractures and fractures extending to the lumbar spine are key factors for the appropriate management of sacral fractures. Importantly, associated systemic (cranial, thoracic, and abdominopelvic) or musculoskeletal injuries should be promptly assessed and addressed. These associated injuries often dictate the management and eventual outcome of sacral fractures and, therefore, any treatment algorithm should take them into consideration. Conclusions: Sacral fractures are complex in nature and often associated with other often-missed injuries. This review summarizes the most relevant associated injuries in sacral fractures and discusses on their appropriate management. PMID:28989838

Toughness-Dominated Regime of Hydraulic Fracturing in Cohesionless Materials

NASA Astrophysics Data System (ADS)

Germanovich, L. N.; Hurt, R. S.; Ayoub, J.; Norman, W. D.

2011-12-01

This work examines the mechanisms of hydraulic fracturing in cohesionless particulate materials with geotechnical, geological, and petroleum applications. For this purpose, experimental techniques have been developed, and used to quantify the initiation and propagation of hydraulic fractures in saturated particulate materials. The fracturing liquid is injected into particulate materials, which are practically cohesionless. The liquid flow is localized in thin self-propagating crack-like conduits. By analogy we call them 'cracks' or 'hydraulic fractures.' When a fracture propagates in a solid, new surfaces are created by breaking material bonds. Consequently, the material is in tension at the fracture tip. Because the particulate material is already 'fractured,' no new surface is created and no fracturing process per se is involved. Therefore, the conventional fracture mechanics principles cannot be directly applied. Based on the laboratory observations, performed on three particulate materials (Georgia Red Clay, silica flour, and fine sand, and their mixtures), this work offers physical concepts to explain the observed phenomena. The goal is to determine the controlling parameters of fracture behavior and to quantify their effects. An important conclusion of our work is that all parts of the cohesionless particulate material (including the tip zone of hydraulic fracture) are likely to be in compression. The compressive stress state is an important characteristic of hydraulic fracturing in particulate materials with low, or no, cohesion (such as were used in our experiments). At present, two kinematic mechanisms of fracture propagation, consistent with the compressive stress regime, can be offered. The first mechanism is based on shear bands propagating ahead of the tip of an open fracture. The second is based on the tensile strain ahead of the fracture tip and reduction of the effective stresses to zero within the leak-off zone. Scaling indicates that in our experiments, there is a high pressure gradient in the leak-off zone in the direction normal to the fracture. Fluid pressure does not decrease considerably along the fracture, however, due to the relatively wide fracture aperture. This suggests that hydraulically induced fractures in unconsolidated materials may be considered to be within the toughness-dominated regime of hydraulic fracturing. Our results indicate that the primary influence on peak or initiation pressure comes from the remote stresses. However, fracture morphology changes significantly with other chosen parameters (stress, flow rate, rheology and permeability). Additionally, an important characteristic feature of fractures in our experiments is the frequent bluntness of the fracture tip, which suggests that plastic deformation at the fracture tip is important. Modeling shows that large openings at the fracture tip correspond to relatively large 'effective' fracture (surface) energy, which can be orders of magnitude greater than for typical (solid) rocks.

Structural-Diagenetic Controls on Fracture Opening in Tight Gas Sandstone Reservoirs, Alberta Foothills

NASA Astrophysics Data System (ADS)

Ukar, Estibalitz; Eichhubl, Peter; Fall, Andras; Hooker, John

2013-04-01

In tight gas reservoirs, understanding the characteristics, orientation and distribution of natural open fractures, and how these relate to the structural and stratigraphic setting are important for exploration and production. Outcrops provide the opportunity to sample fracture characteristics that would otherwise be unknown due to the limitations of sampling by cores and well logs. However, fractures in exhumed outcrops may not be representative of fractures in the reservoir because of differences in burial and exhumation history. Appropriate outcrop analogs of producing reservoirs with comparable geologic history, structural setting, fracture networks, and diagenetic attributes are desirable but rare. The Jurassic to Lower Cretaceous Nikanassin Formation from the Alberta Foothills produces gas at commercial rates where it contains a network of open fractures. Fractures from outcrops have the same diagenetic attributes as those observed in cores <100 km away, thus offering an ideal opportunity to 1) evaluate the distribution and characteristics of opening mode fractures relative to fold cores, hinges and limbs, 2) compare the distribution and attributes of fractures in outcrop vs. core samples, 3) estimate the timing of fracture formation relative to the evolution of the fold-and-thrust belt, and 4) estimate the degradation of fracture porosity due to postkinematic cementation. Cathodoluminescence images of cemented fractures in both outcrop and core samples reveal several generations of quartz and ankerite cement that is synkinematic and postkinematic relative to fracture opening. Crack-seal textures in synkinematic quartz are ubiquitous, and well-developed cement bridges abundant. Fracture porosity may be preserved in fractures wider than ~100 microns. 1-D scanlines in outcrop and core samples indicate fractures are most abundant within small parasitic folds within larger, tight, mesoscopic folds. Fracture intensity is lower away from parasitic folds; intensity progressively decreases from the faulted cores of mesoscopic folds to their forelimbs, with lowest intensities within relatively undeformed backlimb strata. Fracture apertures locally increase adjacent to reverse faults without an overall increase in fracture frequency. Fluid inclusion analyses of crack-seal quartz cement indicate both aqueous and methane-rich inclusions are present. Homogenization temperatures of two-phase inclusions indicate synkinematic fracture cement precipitation and fracture opening under conditions at or near maximum burial of 190-210°C in core samples, and 120-160°C in outcrop samples. In comparison with the fracture evolution in other, less deformed tight-gas sandstone reservoirs such as the Piceance and East Texas basins where fracture opening is primarily controlled by gas generation, gas charge, and pore fluid pressure, these results suggest a strong control of regional tectonic processes on fracture generation. In conjunction with timing and rate of gas charge, rates of fracture cement growth, and stratigraphic-lithological controls, these processes determine the overall distribution of open fractures in these reservoirs.

Structural-Diagenetic Controls on Fracture Opening in Tight Gas Sandstone Reservoirs, Alberta Foothills

NASA Astrophysics Data System (ADS)

Ukar, E.; Eichhubl, P.; Fall, A.; Hooker, J. N.

2012-12-01

In tight gas reservoirs, understanding the characteristics, orientation and distribution of natural open fractures, and how these relate to the structural and stratigraphic setting are important for exploration and production. Outcrops provide the opportunity to sample fracture characteristics that would otherwise be unknown due to the limitations of sampling by cores and well logs. However, fractures in exhumed outcrops may not be representative of fractures in the reservoir because of differences in burial and exhumation history. Appropriate outcrop analogs of producing reservoirs with comparable geologic history, structural setting, fracture networks, and diagenetic attributes are desirable but rare. The Jurassic to Lower Cretaceous Nikanassin Formation from the Alberta Foothills produces gas at commercial rates where it contains a network of open fractures. Fractures from outcrops have the same diagenetic attributes as those observed in cores <100 km away, thus offering an ideal opportunity to 1) evaluate the distribution and characteristics of opening mode fractures relative to fold cores, hinges and limbs, 2) compare the distribution and attributes of fractures in outcrop vs. core samples, 3) estimate the timing of fracture formation relative to the evolution of the fold-and-thrust belt, and 4) estimate the degradation of fracture porosity due to postkinematic cementation. Cathodoluminescence images of cemented fractures in both outcrop and core samples reveal several generations of quartz and ankerite cement that is synkinematic and postkinematic relative to fracture opening. Crack-seal textures in synkinematic quartz are ubiquitous, and well-developed cement bridges abundant. Fracture porosity may be preserved in fractures wider than ~100 microns. 1-D scanlines in outcrop and core samples indicate fractures are most abundant within small parasitic folds within larger, tight, mesoscopic folds. Fracture intensity is lower away from parasitic folds; intensity progressively decreases from the faulted cores of mesoscopic folds to their forelimbs, with lowest intensities within relatively undeformed backlimb strata. Fracture apertures locally increase adjacent to reverse faults without an overall increase in fracture frequency. Fluid inclusion analyses of crack-seal quartz cement indicate both aqueous and methane-rich inclusions are present. Homogenization temperatures of two-phase inclusions indicate synkinematic fracture cement precipitation and fracture opening under conditions at or near maximum burial of 190-210°C in core samples, and 120-160°C in outcrop samples. In comparison with the fracture evolution in other, less deformed tight-gas sandstone reservoirs such as the Piceance and East Texas basins where fracture opening is primarily controlled by gas generation, gas charge, and pore fluid pressure, these results suggest a strong control of regional tectonic processes on fracture generation. In conjunction with timing and rate of gas charge, rates of fracture cement growth, and stratigraphic-lithological controls, these processes determine the overall distribution of open fractures in these reservoirs.

Skull fracture

MedlinePlus

Basilar skull fracture; Depressed skull fracture; Linear skull fracture ... Skull fractures may occur with head injuries . The skull provides good protection for the brain. However, a severe impact ...

Coupling Hydraulic Fracturing Propagation and Gas Well Performance for Simulation of Production in Unconventional Shale Gas Reservoirs

NASA Astrophysics Data System (ADS)

Wang, C.; Winterfeld, P. H.; Wu, Y. S.; Wang, Y.; Chen, D.; Yin, C.; Pan, Z.

2014-12-01

Hydraulic fracturing combined with horizontal drilling has made it possible to economically produce natural gas from unconventional shale gas reservoirs. An efficient methodology for evaluating hydraulic fracturing operation parameters, such as fluid and proppant properties, injection rates, and wellhead pressure, is essential for the evaluation and efficient design of these processes. Traditional numerical evaluation and optimization approaches are usually based on simulated fracture properties such as the fracture area. In our opinion, a methodology based on simulated production data is better, because production is the goal of hydraulic fracturing and we can calibrate this approach with production data that is already known. This numerical methodology requires a fully-coupled hydraulic fracture propagation and multi-phase flow model. In this paper, we present a general fully-coupled numerical framework to simulate hydraulic fracturing and post-fracture gas well performance. This three-dimensional, multi-phase simulator focuses on: (1) fracture width increase and fracture propagation that occurs as slurry is injected into the fracture, (2) erosion caused by fracture fluids and leakoff, (3) proppant subsidence and flowback, and (4) multi-phase fluid flow through various-scaled anisotropic natural and man-made fractures. Mathematical and numerical details on how to fully couple the fracture propagation and fluid flow parts are discussed. Hydraulic fracturing and production operation parameters, and properties of the reservoir, fluids, and proppants, are taken into account. The well may be horizontal, vertical, or deviated, as well as open-hole or cemented. The simulator is verified based on benchmarks from the literature and we show its application by simulating fracture network (hydraulic and natural fractures) propagation and production data history matching of a field in China. We also conduct a series of real-data modeling studies with different combinations of hydraulic fracturing parameters and present the methodology to design these operations with feedback of simulated production data. The unified model aids in the optimization of hydraulic fracturing design, operations, and production.

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

Discrete fracture modeling of multiphase flow and hydrocarbon production in fractured shale or low permeability reservoirs

NASA Astrophysics Data System (ADS)

Hao, Y.; Settgast, R. R.; Fu, P.; Tompson, A. F. B.; Morris, J.; Ryerson, F. J.

2016-12-01

It has long been recognized that multiphase flow and transport in fractured porous media is very important for various subsurface applications. Hydrocarbon fluid flow and production from hydraulically fractured shale reservoirs is an important and complicated example of multiphase flow in fractured formations. The combination of horizontal drilling and hydraulic fracturing is able to create extensive fracture networks in low permeability shale rocks, leading to increased formation permeability and enhanced hydrocarbon production. However, unconventional wells experience a much faster production decline than conventional hydrocarbon recovery. Maintaining sustainable and economically viable shale gas/oil production requires additional wells and re-fracturing. Excessive fracturing fluid loss during hydraulic fracturing operations may also drive up operation costs and raise potential environmental concerns. Understanding and modeling processes that contribute to decreasing productivity and fracturing fluid loss represent a critical component for unconventional hydrocarbon recovery analysis. Towards this effort we develop a discrete fracture model (DFM) in GEOS (LLNL multi-physics computational code) to simulate multiphase flow and transfer in hydraulically fractured reservoirs. The DFM model is able to explicitly account for both individual fractures and their surrounding rocks, therefore allowing for an accurate prediction of impacts of fracture-matrix interactions on hydrocarbon production. We apply the DFM model to simulate three-phase (water, oil, and gas) flow behaviors in fractured shale rocks as a result of different hydraulic stimulation scenarios. Numerical results show that multiphase flow behaviors at the fracture-matrix interface play a major role in controlling both hydrocarbon production and fracturing fluid recovery rates. The DFM model developed in this study will be coupled with the existing hydro-fracture model to provide a fully integrated geomechanical and reservoir simulation capability for an accurate prediction and assessment of hydrocarbon production and hydraulic fracturing performance. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

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.

Is there a specific fracture ‘cascade'?

PubMed Central

Melton, L Joseph; Amin, Shreyasee

2013-01-01

Different kinds of epidemiologic data provide varying views of the relationships among the main osteoporotic fractures. Descriptive incidence data indicate that distal forearm fractures typically occur earlier than vertebral fractures that, in turn, precede hip fractures late in life. In addition, relative risk estimates document the fact that one osteoporotic fracture increases the risk of subsequent ones. These two observations support the notion of a ‘fracture cascade' and justify the recent emphasis on secondary prevention, that is, more aggressive treatment of patients presenting with a fracture in order to prevent recurrences. However, the absolute risk of a subsequent fracture given an initial one is modest, and the degree to which the second fracture can be attributed to the first one is unclear. Moreover, the osteoporotic fractures encountered in the majority of patients are the first one experienced, and even these initial fractures lead to substantial morbidity and cost. These latter points reemphasize the importance of primary prevention, that is, the management of bone loss and other risk factors to prevent the first fracture. Continued efforts are needed to refine risk assessment algorithms so that candidates for such fracture prophylaxis can be identified more accurately and efficiently. PMID:24575296

Modeling of Propagation of Interacting Cracks Under Hydraulic Pressure Gradient

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

Huang, Hai; Mattson, Earl Douglas; Podgorney, Robert Karl

A robust and reliable numerical model for fracture initiation and propagation, which includes the interactions among propagating fractures and the coupling between deformation, fracturing and fluid flow in fracture apertures and in the permeable rock matrix, would be an important tool for developing a better understanding of fracturing behaviors of crystalline brittle rocks driven by thermal and (or) hydraulic pressure gradients. In this paper, we present a physics-based hydraulic fracturing simulator based on coupling a quasi-static discrete element model (DEM) for deformation and fracturing with conjugate lattice network flow model for fluid flow in both fractures and porous matrix. Fracturingmore » is represented explicitly by removing broken bonds from the network to represent microcracks. Initiation of new microfractures and growth and coalescence of the microcracks leads to the formation of macroscopic fractures when external and/or internal loads are applied. The coupled DEM-network flow model reproduces realistic growth pattern of hydraulic fractures. In particular, simulation results of perforated horizontal wellbore clearly demonstrate that elastic interactions among multiple propagating fractures, fluid viscosity, strong coupling between fluid pressure fluctuations within fractures and fracturing, and lower length scale heterogeneities, collectively lead to complicated fracturing patterns.« less

Numerical simulation and fracture identification of dual laterolog in organic shale

NASA Astrophysics Data System (ADS)

Maojin, Tan; Peng, Wang; Qiong, Liu

2012-09-01

Fracture is one of important spaces in shale oil and shale gas reservoirs, and fractures identification and evaluation are an important part in organic shale interpretation. According to the fractured shale gas reservoir, a physical model is set up to study the dual laterolog logging responses. First, based on the principle of dual laterolog, three-dimensional finite element method (FEM) is used to simulate the dual laterolog responses in various formation models with different fractures widths, different fracture numbers, different fractures inclination angle. All the results are extremely important for the fracture identification and evaluation in shale reservoirs. Appointing to different base rock resistivity models, the fracture models are constructed respectively through a number of numerical simulation, and the fracture porosity can be calculated by solving the corresponding formulas. A case study about organic shale formation is analyst and discussed, and the fracture porosity is calculated from dual laterolog. The fracture evaluation results are also be validated right by Full borehole Micro-resistivity Imaging (FMI). So, in case of the absence of borehole resistivity imaging log, the dual laterolog resistivity can be used to estimate the fracture development.

Relationships between fractures

NASA Astrophysics Data System (ADS)

Peacock, D. C. P.; Sanderson, D. J.; Rotevatn, A.

2018-01-01

Fracture systems comprise many fractures that may be grouped into sets based on their orientation, type and relative age. The fractures are often arranged in a network that involves fracture branches that interact with one another. Interacting fractures are termed geometrically coupled when they share an intersection line and/or kinematically coupled when the displacements, stresses and strains of one fracture influences those of the other. Fracture interactions are characterised in terms of the following. 1) Fracture type: for example, whether they have opening (e.g., joints, veins, dykes), closing (stylolites, compaction bands), shearing (e.g., faults, deformation bands) or mixed-mode displacements. 2) Geometry (e.g., relative orientations) and topology (the arrangement of the fractures, including their connectivity). 3) Chronology: the relative ages of the fractures. 4) Kinematics: the displacement distributions of the interacting fractures. It is also suggested that interaction can be characterised in terms of mechanics, e.g., the effects of the interaction on the stress field. It is insufficient to describe only the components of a fracture network, with fuller understanding coming from determining the interactions between the different components of the network.

An Equivalent Fracture Modeling Method

NASA Astrophysics Data System (ADS)

Li, Shaohua; Zhang, Shujuan; Yu, Gaoming; Xu, Aiyun

2017-12-01

3D fracture network model is built based on discrete fracture surfaces, which are simulated based on fracture length, dip, aperture, height and so on. The interesting area of Wumishan Formation of Renqiu buried hill reservoir is about 57 square kilometer and the thickness of target strata is more than 2000 meters. In addition with great fracture density, the fracture simulation and upscaling of discrete fracture network model of Wumishan Formation are very intense computing. In order to solve this problem, a method of equivalent fracture modeling is proposed. First of all, taking the fracture interpretation data obtained from imaging logging and conventional logging as the basic data, establish the reservoir level model, and then under the constraint of reservoir level model, take fault distance analysis model as the second variable, establish fracture density model by Sequential Gaussian Simulation method. Increasing the width, height and length of fracture, at the same time decreasing its density in order to keep the similar porosity and permeability after upscaling discrete fracture network model. In this way, the fracture model of whole interesting area can be built within an accepted time.

Description and analysis of cored hydraulic fractures -- Lost Hills field, Kern County, California

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

Fast, R.E.; Murer, A.S.; Timmer, R.S.

1994-05-01

An inclined observation well was drilled in shallow (2,000 ft) Opal-A diatomite. Seven sand-propped hydraulic fractures were cored and recovered. The hydraulic fractures were found within 5[degree] of the azimuth measured with tilt meters and were tilted 15[degree] from vertical, oriented perpendicular to the formation bedding dip. Hydraulic fractures widths ranged from less than one sand grain (40/60 mesh) to 0.4 in. Scanning electron microscopy (SEM) examination of fracture faces showed no damage to the matrix from proppant embedment or compaction, and no evidence of guard residue was detected in the proppant pack or on the formation face. Fractures appearmore » to be considerably longer than modeled. Three closely spaced fractures are interpreted to be branches of a single hydraulic fracture treatment. This paper presents a description of the fractures recovered during coring in Well OO2. Findings related to fracture dimensions and orientations, fracture sources, fracture permeability measurements, and fracture characteristics (proppant embedment, presence of gel residue) are presented. Implications related to field development are discussed.« less

Fractography and fracture toughness of human dentin.

PubMed

Yan, J; Taskonak, B; Mecholsky, J J

2009-10-01

Dentin, the mineralized tissue forming the bulk of the tooth, serves as an energy-absorbing cushion for the hard, wear-resistant enamel and protects the inner soft tissues. Several studies used fracture mechanics methods to study the fracture toughness of dentin. However, all of them utilized precracks and cannot be used to estimate the intrinsic critical flaw size of dentin. We applied quantitative fractography to study the fracture pattern and fracture toughness of human dentin. Sixteen specimens were prepared from the coronal dentin and fractured in three-point flexure. Fracture surfaces were examined using a scanning electron microscope and the fracture toughness was calculated using a fracture mechanics equation. It was found that human dentin has a fracture surface similar to those of brittle materials. Twist hackle markings were observed and were used to identify the fracture origins. Average fracture toughness of all specimens was found to be 2.3 MPa m(1/2) and the average critical flaw size was estimated to 120 mum. It is suggested that fractography is a promising technique in analyzing the fracture of dentin under catastrophic failure.

Biomechanical Concepts for Fracture Fixation

PubMed Central

Bottlang, Michael; Schemitsch, Christine E.; Nauth, Aaron; Routt, Milton; Egol, Kenneth; Cook, Gillian E.; Schemitsch, Emil H.

2015-01-01

Application of the correct fixation construct is critical for fracture healing and long-term stability; however, it is a complex issue with numerous significant factors. This review describes a number of common fracture types, and evaluates their currently available fracture fixation constructs. In the setting of complex elbow instability, stable fixation or radial head replacement with an appropriately sized implant in conjunction with ligamentous repair is required to restore stability. For unstable sacral fractures, “standard” iliosacral screw fixation is not sufficient for fractures with vertical or multiplanar instabilities. Periprosthetic femur fractures, in particular Vancouver B1 fractures, have increased stability when using 90/90 fixation versus a single locking plate. Far Cortical Locking combines the concept of dynamization with locked plating in order to achieve superior healing of a distal femur fracture. Finally, there is no ideal construct for syndesmotic fracture stabilization; however, these fractures should be fixed using a device that allows for sufficient motion in the syndesmosis. In general, orthopaedic surgeons should select a fracture fixation construct that restores stability and promotes healing at the fracture site, while reducing the potential for fixation failure. PMID:26584263

Sphenoid Sinus and Sphenoid Bone Fractures in Patients with Craniomaxillofacial Trauma

PubMed Central

Cantini Ardila, Jorge Ernesto; Mendoza, Miguel Ángel Rivera; Ortega, Viviana Gómez

2013-01-01

Background and Purpose Sphenoid bone fractures and sphenoid sinus fractures have a high morbidity due to its association with high-energy trauma. The purpose of this study is to describe individuals with traumatic injuries from different mechanisms and attempt to determine if there is any relationship between various isolated or combined fractures of facial skeleton and sphenoid bone and sphenoid sinus fractures. Methods We retrospectively studied hospital charts of all patients who reported to the trauma center at Hospital de San José with facial fractures from December 2009 to August 2011. All patients were evaluated by computed tomography scan and classified into low-, medium-, and high-energy trauma fractures, according to the classification described by Manson. Design This is a retrospective descriptive study. Results The study data were collected as part of retrospective analysis. A total of 250 patients reported to the trauma center of the study hospital with facial trauma. Thirty-eight patients were excluded. A total of 212 patients had facial fractures; 33 had a combination of sphenoid sinus and sphenoid bone fractures, and facial fractures were identified within this group (15.5%). Gender predilection was seen to favor males (77.3%) more than females (22.7%). The mean age of the patients was 37 years. Orbital fractures (78.8%) and maxillary fractures (57.5%) were found more commonly associated with sphenoid sinus and sphenoid bone fractures. Conclusions High-energy trauma is more frequently associated with sphenoid fractures when compared with medium- and low-energy trauma. There is a correlation between facial fractures and sphenoid sinus and sphenoid bone fractures. A more exhaustive multicentric case-control study with a larger sample and additional parameters will be essential to reach definite conclusions regarding the spectrum of fractures of the sphenoid bone associated with facial fractures. PMID:24436756

Spatial arrangement of faults and opening-mode fractures

NASA Astrophysics Data System (ADS)

Laubach, S. E.; Lamarche, J.; Gauthier, B. D. M.; Dunne, W. M.; Sanderson, David J.

2018-03-01

Spatial arrangement is a fundamental characteristic of fracture arrays. The pattern of fault and opening-mode fracture positions in space defines structural heterogeneity and anisotropy in a rock volume, governs how faults and fractures affect fluid flow, and impacts our understanding of the initiation, propagation and interactions during the formation of fracture patterns. This special issue highlights recent progress with respect to characterizing and understanding the spatial arrangements of fault and fracture patterns, providing examples over a wide range of scales and structural settings. Five papers describe new methods and improvements of existing techniques to quantify spatial arrangement. One study unravels the time evolution of opening-mode fracture spatial arrangement, which are data needed to compare natural patterns with progressive fracture growth in kinematic and mechanical models. Three papers investigate the role of evolving diagenesis in localizing fractures by mechanical stratigraphy and nine discuss opening-mode fracture spatial arrangement. Two papers show the relevance of complex cluster patterns to unconventional reservoirs through examples of fractures in tight gas sandstone horizontal wells, and a study of fracture arrangement in shale. Four papers demonstrate the roles of folds in fracture localization and the development spatial patterns. One paper models along-fault friction and fluid pressure and their effects on fault-related fracture arrangement. Contributions address deformation band patterns in carbonate rocks and fault size and arrangement above a detachment fault. Three papers describe fault and fracture arrangements in basement terrains, and three document fracture patterns in shale. This collection of papers points toward improvement in field methods, continuing improvements in computer-based data analysis and creation of synthetic fracture patterns, and opportunities for further understanding fault and fracture attributes in the subsurface through coupled spatial, size, and pattern analysis.

Defining hip fracture with claims data: outpatient and provider claims matter.

PubMed

Berry, S D; Zullo, A R; McConeghy, K; Lee, Y; Daiello, L; Kiel, D P

2017-07-01

Medicare claims are commonly used to identify hip fractures, but there is no universally accepted definition. We found that a definition using inpatient claims identified fewer fractures than a definition including outpatient and provider claims. Few additional fractures were identified by including inconsistent diagnostic and procedural codes at contiguous sites. Medicare claims data is commonly used in research studies to identify hip fractures, but there is no universally accepted definition of fracture. Our purpose was to describe potential misclassification when hip fractures are defined using Medicare Part A (inpatient) claims without considering Part B (outpatient and provider) claims and when inconsistent diagnostic and procedural codes occur at contiguous fracture sites (e.g., femoral shaft or pelvic). Participants included all long-stay nursing home residents enrolled in Medicare Parts A and B fee-for-service between 1/1/2008 and 12/31/2009 with follow-up through 12/31/2011. We compared the number of hip fractures identified using only Part A claims to (1) Part A plus Part B claims and (2) Part A and Part B claims plus discordant codes at contiguous fracture sites. Among 1,257,279 long-stay residents, 40,932 (3.2%) met the definition of hip fracture using Part A claims, and 41,687 residents (3.3%) met the definition using Part B claims. 4566 hip fractures identified using Part B claims would not have been captured using Part A claims. An additional 227 hip fractures were identified after considering contiguous fracture sites. When ascertaining hip fractures, a definition using outpatient and provider claims identified 11% more fractures than a definition with only inpatient claims. Future studies should publish their definition of fracture and specify if diagnostic codes from contiguous fracture sites were used.

Contaminant transport in fractured rocks with significant matrix permeability, using natural fracture geometries

NASA Astrophysics Data System (ADS)

Odling, Noelle E.; Roden, Julie E.

1997-09-01

Some results from numerical models of flow and contaminant transport in fractured permeable rocks, where fractures are more conductive than rock matrix, are described. The 2D flow field in the fractured and permeable rock matrix is calculated using a finite difference, 'conductance mesh' method, and the contaminant transport is simulated by particle tracking methods using an advection-biased, random walk technique. The model is applied to simulated and naturally occurring fracture patterns. The simulated pattern is an en echelon array of unconnected fractures, as an example of a common, naturally occurring fracture geometry. Two natural fracture patterns are used: one of unconnected, sub-parallel fractures and one with oblique fracture sets which is well connected. Commonly occurring matrix permeability and fracture aperture values are chosen. The simulations show that the presence of fractures creates complex and heterogeneous flow fields and contaminant distribution in the permeable rock matrix. The modelling results have shown that some effects are non-intuitive and therefore difficult to foresee without the help of a model. With respect to contaminant transport rates and plume heterogeneity, it was found that fracture connectivity (crucial when the matrix is impermeable) can play a secondary role to fracture orientation and density. Connected fracture systems can produce smooth break-through curves of contaminants summed over, for example, a bore-hole length, whereas in detail the contaminant plume is spatially highly heterogeneous. Close to a constant-pressure boundary (e.g. an extraction bore-hole), flow and contaminants can be channelled by fractures. Thus observations at a bore-hole may suggest that contaminants are largely confined to the fracture system, when, in fact, significant contamination resides in the matrix.

Simple X-ray versus ultrasonography examination in blunt chest trauma: effective tools of accurate diagnosis and considerations for rib fractures.

PubMed

Hwang, Eun Gu; Lee, Yunjung

2016-12-01

Simple radiography is the best diagnostic tool for rib fractures caused by chest trauma, but it has some limitations. Thus, other tools are also being used. The aims of this study were to investigate the effectiveness of ultrasonography (US) for identifying rib fractures and to identify influencing factors of its effectiveness. Between October 2003 and August 2007, 201 patients with blunt chest trauma were available to undergo chest radiographic and US examinations for diagnosis of rib fractures. The two modalities were compared in terms of effectiveness based on simple radiographic readings and US examination results. We also investigated the factors that influenced the effectiveness of US examination. Rib fractures were detected on radiography in 69 patients (34.3%) but not in 132 patients. Rib fractures were diagnosed by using US examination in 160 patients (84.6%). Of the 132 patients who showed no rib fractures on radiography, 92 showed rib fractures on US. Among the 69 patients of rib fracture detected on radiography, 33 had additional rib fractures detected on US. Of the patients, 76 (37.8%) had identical radiographic and US results, and 125 (62.2%) had fractures detected on US that were previously undetected on radiography or additional fractures detected on US. Age, duration until US examination, and fracture location were not significant influencing factors. However, in the group without detected fractures on radiography, US showed a more significant effectiveness than in the group with detected fractures on radiography ( P =0.003). US examination could detect unnoticed rib fractures on simple radiography. US examination is especially more effective in the group without detected fractures on radiography. More attention should be paid to patients with chest trauma who have no detected fractures on radiography.

The utility of dual-energy X-ray absorptiometry, calcaneal quantitative ultrasound, and fracture risk indices (FRAX® and Osteoporosis Risk Assessment Instrument) for the identification of women with distal forearm or hip fractures: A pilot study.

PubMed

Esmaeilzadeh, Sina; Cesme, Fatih; Oral, Aydan; Yaliman, Ayse; Sindel, Dilsad

2016-08-01

Dual-energy X-ray absorptiometry (DXA) is considered the "gold standard" in predicting osteoporotic fractures. Calcaneal quantitative ultrasound (QUS) variables are also known to predict fractures. Fracture risk assessment tools may also guide us for the detection of individuals at high risk for fractures. The aim of this case-control study was to evaluate the utility of DXA bone mineral density (BMD), calcaneal QUS parameters, FRAX® (Fracture Risk Assessment Tool), and Osteoporosis Risk Assessment Instrument (ORAI) for the discrimination of women with distal forearm or hip fractures. This case-control study included 20 women with a distal forearm fracture and 18 women with a hip fracture as cases and 76 age-matched women served as controls. BMD at the spine, proximal femur, and radius was measured using DXA and acoustic parameters of bone were obtained using a calcaneal QUS device. FRAX® 10-year probability of fracture and ORAI scores were also calculated in all participants. Receiver operating characteristic (ROC) analysis was used to assess fracture discriminatory power of all the tools. While all DXA BMD, and QUS variables and FRAX® fracture probabilities demonstrated significant areas under the ROC curves for the discrimination of hip-fractured women and those without, only 33% radius BMD, broadband ultrasound attenuation (BUA), and FRAX® major osteoporotic fracture probability calculated without BMD showed significant discriminatory power for distal forearm fractures. It can be concluded that QUS variables, particularly BUA, and FRAX® major osteoporotic fracture probability without BMD are good candidates for the identification of both hip and distal forearm fractures.

The influence of local bone quality on fracture pattern in proximal humerus fractures.

PubMed

Mazzucchelli, Ruben A; Jenny, Katharina; Zdravkovic, Vilijam; Erhardt, Johannes B; Jost, Bernhard; Spross, Christian

2018-02-01

Bone mineral density and fracture morphology are widely discussed and relevant factors when considering the different treatment options for proximal humerus fractures. It was the aim of this study to investigate the influence of local bone quality on fracture patterns of the Neer classification as well as on fracture impaction angle in these injuries. All acute, isolated and non-pathological proximal humerus fractures admitted to our emergency department were included. The fractures were classified according to Neer and the humeral head impaction angle was measured. Local bone quality was assessed using the Deltoid Tuberosity Index (DTI). The distribution between DTI and fracture pattern was analysed. 191 proximal humerus fractures were included (61 men, mean age 59 years; 130 women, mean age 69.5). 77 fractures (40%) were classified as one-part, 72 (38%) were two-part, 24 (13%) were three- and four-part and 18 (9%) were fracture dislocations. 30 fractures (16%) were varus impacted, whereas 45 fractures (24%) were classified as valgus impacted. The mean DTI was 1.48. Valgus impaction significantly correlated with good bone quality (DTI ≥ 1.4; p = 0.047) whereas no such statistical significance was found for the Neer fracture types. We found that valgus impaction significantly depended on good bone quality. However, neither varus impaction nor any of the Neer fracture types correlated with bone quality. We conclude that the better bone quality of valgus impacted fractures may be a reason for their historically benign amenability to ORIF. On the other hand, good local bone quality does not prevent fracture comminution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Burden of non-hip, non-vertebral fractures on quality of life in postmenopausal women: the Global Longitudinal study of Osteoporosis in Women (GLOW)

PubMed Central

Roux, C.; Wyman, A.; Hooven, F. H.; Gehlbach, S. H.; Adachi, J. D.; Chapurlat, R. D.; Compston, J. E.; Cooper, C.; Díez-Pérez, A.; Greenspan, S. L.; LaCroix, A. Z.; Netelenbos, J. C.; Pfeilschifter, J.; Rossini, M.; Saag, K. G.; Sambrook, P. N.; Silverman, S.; Siris, E. S.; Watts, N. B.; Boonen, S.

2016-01-01

Purpose Most fracture studies have focused on hip and vertebral fractures, but there is growing evidence that non-hip, non-vertebral (NHNV) fractures also result in substantial morbidity and healthcare costs. We sought to assess the effect of NHNV fractures on quality of life. Methods We analyzed 1-year incidences of hip, spine, major NHNV (pelvis/leg, shoulder/arm) and minor NHNV (wrist/hand, ankle/foot, rib/clavicle) fractures among women from the GLOW registry, a prospective, multinational, observational cohort study. Health-related quality of life (HRQL) was analyzed using EuroQol EQ-5D and the SF-36 health survey. Results Among 50,461 women analyzed, there were 1,822 fractures (57% minor NHNV, 26% major NHNV, 10% spine, 7% hip) over 1 year. Spine fractures had the greatest detrimental effect on EQ-5D summary scores, followed by major NHNV and hip fractures. The amount of women with mobility problems increased most for those with major NHNV and spine fractures (both +8%); spine fractures were associated with the largest increases in problems with self care (+11%), activities (+14%), and pain/discomfort (+12%). Decreases in physical function and health status were greatest for women with spine or hip fractures. Multivariable modeling found that EQ-5D reduction was greatest for spine fractures, followed by hip and major/minor NHNV. Significant reductions in SF-36 physical function were found only for spine and major NHNV fractures. Conclusion This prospective study shows that NHNV fractures have a detrimental effect on HRQL. As NHNV fractures account for >80% of incident fractures, efforts to optimize osteoporosis care should include prevention of NHNV fractures. PMID:22398855

Validation of fragility fractures in primary care electronic medical records: A population-based study.

PubMed

Martinez-Laguna, Daniel; Soria-Castro, Alberto; Carbonell-Abella, Cristina; Orozco-López, Pilar; Estrada-Laza, Pilar; Nogues, Xavier; Díez-Perez, Adolfo; Prieto-Alhambra, Daniel

2017-11-28

Electronic medical records databases use pre-specified lists of diagnostic codes to identify fractures. These codes, however, are not specific enough to disentangle traumatic from fragility-related fractures. We report on the proportion of fragility fractures identified in a random sample of coded fractures in SIDIAP. Patients≥50 years old with any fracture recorded in 2012 (as per pre-specified ICD-10 codes) and alive at the time of recruitment were eligible for this retrospective observational study in 6 primary care centres contributing to the SIDIAP database (www.sidiap.org). Those with previous fracture/s, non-responders, and those with dementia or a serious psychiatric disease were excluded. Data on fracture type (traumatic vs fragility), skeletal site, and basic patient characteristics were collected. Of 491/616 (79.7%) patients with a registered fracture in 2012 who were contacted, 331 (349 fractures) were included. The most common fractures were forearm (82), ribs (38), and humerus (32), and 225/349 (64.5%) were fragility fractures, with higher proportions for classic osteoporotic sites: hip, 91.7%; spine, 87.7%; and major fractures, 80.5%. This proportion was higher in women, the elderly, and patients with a previously coded diagnosis of osteoporosis. More than 4 in 5 major fractures recorded in SIDIAP are due to fragility (non-traumatic), with higher proportions for hip (92%) and vertebral (88%) fracture, and a lower proportion for fractures other than major ones. Our data support the validity of SIDIAP for the study of the epidemiology of osteoporotic fractures. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

Radial and tibial fracture repair with external skeletal fixation. Effects of fracture type, reduction, and complications on healing.

PubMed

Johnson, A L; Kneller, S K; Weigel, R M

1989-01-01

Twenty-eight consecutive fractures of the canine radius and tibia were treated with external skeletal fixation as the primary method of stabilization. The time of fixation removal (T1) and the time to unsupported weight-bearing (T2) were correlated with: (1) bone involved; (2) communication of the fracture with the external environment; (3) severity of the fracture; (4) proximity of the fracture to the nutrient artery; (5) method of reduction; (6) diaphyseal displacement after reduction; and (7) gap between cortical fragments after reduction. The Kruskal-Wallis one-way analysis of variance was used to test the correlation with p less than .05 set as the criterion for significance. The median T1 was 10 weeks and the median T2 was 11 weeks. None of the variables correlated significantly with either of the healing times; however, there was a strong trend toward longer healing times associated with open fractures and shorter healing times associated with closed reduction. Periosteal and endosteal callus uniting the fragments were observed radiographically in comminuted fractures, with primary bone union observed in six fractures in which anatomic reduction was achieved. Complications observed in the treatment of these fractures included: bone lysis around pins (27 fractures), pin track drainage (27 fractures), pin track hemorrhage (1 fracture), periosteal reaction around pins (27 fractures), radiographic signs consistent with osteomyelitis (12 fractures), degenerative joint disease (2 dogs), and nonunion (1 fracture). Valgus or rotational malalignment resulted in 16 malunions of fractures. One external fixation device was replaced and four loose pins were removed before the fractures healed. One dog was treated with antibiotics during the postoperative period because clinical signs of osteomyelitis appeared.(ABSTRACT TRUNCATED AT 250 WORDS)

Mathematical modeling and simulation analysis of hydraulic fracture propagation in three-layered poro-elastic media

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

Moon, H.Y.; Advani, S.H.; Lee, T.S.

1992-11-01

Hydraulic fracturing plays a pivotal role in the enhancement of oil and gas production recovery from low permeability reservoirs. The process of hydraulic fracturing entails the generation of a fracture by pumping fluids blended with special chemicals and proppants into the payzone at high injection rates and pressures to extend and wedge fractures. The mathematical modeling of hydraulically induced fractures generally incorporates coupling between the formation elasticity, fracture fluid flow, and fracture mechanics equations governing the formation structural responses, fluid pressure profile, and fracture growth. Two allied unsymmetric elliptic fracture models are developed for fracture configuration evolutions in three-layered rockmore » formations. The first approach is based on a Lagrangian formulation incorporating pertinent energy components associated with the formation structural responses and fracture fluid flow. The second model is based on a generalized variational principle, introducing an energy rate related functional. These models initially simulate a penny-shaped fracture, which becomes elliptic if the crack tips encounters (upper and/or lower) barriers with differential reservoir properties (in situ stresses, 16 elastic moduli, and fracture toughness-contrasts and fluid leak-off characteristics). The energy rate component magnitudes are determined to interpret the governing hydraulic fracture mechanisms during fracture evolution. The variational principle is extended to study the phenomenon and consequences of fluid lag in fractures. Finally, parametric sensitivity and energy rate investigations to evaluate the roles of controllable hydraulic treatment variables and uncontrollable reservoir property characterization parameters are performed. The presented field applications demonstrate the overall capabilities of the developed models. These studies provide stimulation treatment guidelines for fracture configuration design, control, and optimization.« less

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

Characterising rock fracture aperture-spacing relationships using power-law relationships: some considerations

NASA Astrophysics Data System (ADS)

Brook, Martin; Hebblewhite, Bruce; Mitra, Rudrajit

2016-04-01

The size-scaling of rock fractures is a well-studied problem in geology, especially for permeability quantification. The intensity of fractures may control the economic exploitation of fractured reservoirs because fracture intensity describes the abundance of fractures potentially available for fluid flow. Moreover, in geotechnical engineering, fractures are important for parameterisation of stress models and excavation design. As fracture data is often collected from widely-spaced boreholes where core recovery is often incomplete, accurate interpretation and representation of fracture aperture-frequency relationships from sparse datasets is important. Fracture intensity is the number of fractures encountered per unit length along a sample scanline oriented perpendicular to the fractures in a set. Cumulative frequency of fractures (F) is commonly related to fracture aperture (A) in the form of a power-law (F = aA-b), with variations in the size of the a coefficient between sites interpreted to equate to fracture frequency for a given aperture (A). However, a common flaw in this approach is that even a small change in b can have a large effect on the response of the fracture frequency (F) parameter. We compare fracture data from the Late Permian Rangal Coal Measures from Australia's Bowen Basin, with fracture data from Jurassic carbonates from the Sierra Madre Oriental, northeastern Mexico. Both power-law coefficient a and exponent b control the fracture aperture-frequency relationship in conjunction with each other; that is, power-laws with relatively low a coefficients have relatively high b exponents and vice versa. Hence, any comparison of different power-laws must take both a and b into consideration. The corollary is that different sedimentary beds in the Sierra Madre carbonates do not show ˜8× the fracture frequency for a given fracture aperture, as based solely on the comparison of coefficient a. Rather, power-law "sensitivity factors" developed from both Sierra Madre and the Bowen Basin span similar ranges, indicating that the factor of increase in frequency (F) for a doubling of aperture size (A) shows similar relationships and variability from both sites. Despite their limitations, we conclude that fracture aperture-frequency power-law relationships are valid and, when interpreted carefully, provide a useful basis for comparing rock fracture distributions across different sites.

3D Numerical Modeling of the Propagation of Hydraulic Fracture at Its Intersection with Natural (Pre-existing) Fracture

NASA Astrophysics Data System (ADS)

Dehghan, Ali Naghi; Goshtasbi, Kamran; Ahangari, Kaveh; Jin, Yan; Bahmani, Aram

2017-02-01

A variety of 3D numerical models were developed based on hydraulic fracture experiments to simulate the propagation of hydraulic fracture at its intersection with natural (pre-existing) fracture. Since the interaction between hydraulic and pre-existing fractures is a key condition that causes complex fracture patterns, the extended finite element method was employed in ABAQUS software to simulate the problem. The propagation of hydraulic fracture in a fractured medium was modeled in two horizontal differential stresses (Δ σ) of 5e6 and 10e6 Pa considering different strike and dip angles of pre-existing fracture. The rate of energy release was calculated in the directions of hydraulic and pre-existing fractures (G_{{frac}} /G_{{rock}}) at their intersection point to determine the fracture behavior. Opening and crossing were two dominant fracture behaviors during the hydraulic and pre-existing fracture interaction at low and high differential stress conditions, respectively. The results of numerical studies were compared with those of experimental models, showing a good agreement between the two to validate the accuracy of the models. Besides the horizontal differential stress, strike and dip angles of the natural (pre-existing) fracture, the key finding of this research was the significant effect of the energy release rate on the propagation behavior of the hydraulic fracture. This effect was more prominent under the influence of strike and dip angles, as well as differential stress. The obtained results can be used to predict and interpret the generation of complex hydraulic fracture patterns in field conditions.

A Year of Fractures: a snapshot analysis of the logistics, problems and outcomes of a hospital-based fracture liaison service.

PubMed

Vaile, J H; Sullivan, L; Connor, D; Bleasel, J F

2013-10-01

Our fracture liaison service identifies patients with low trauma fractures, determines the need for osteoporosis therapy and instigates therapy if necessary. We describe the tracking and outcome of 768 patients attending our emergency department over 1 year and discuss the problems we encountered and potential solutions. Osteoporotic fractures result in substantial morbidity, mortality and economic cost, and patients sustaining a first fracture are known to be at higher risk of sustaining future fracture. Treatment of at-risk patients has been shown to assist in prevention of future fracture including hip fracture. We established a "First Fracture Project" to identify and treat these patients in 2003. We assessed "A Year of Fractures": the logistics, outcome and problems in tracking patients presenting to our emergency department with a low trauma fracture by our fracture liaison service, over 1 year from July 2008 to June 2009. Patients were tracked by our osteoporosis nurse and offered assessment, and treatment where necessary. In 1 year, 768 patients aged 50 or over were identified from emergency department records as attending with a low trauma fracture. About 84 % of patients eventually received assessment. Of the162 patients progressing through the entire process, 74 % had osteoporosis treatment planned and/or commenced. Our fracture liaison service was effective at identifying most low trauma fracture patients at risk of further fracture and providing access to osteoporosis assessment. There were many difficulties: we outline logistic and practical issues in delivering our service and suggest potential improvements.

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.

Fracturesis Jointitis: Causes, Symptoms, and Treatment in Groundwater Communities.

PubMed

Manda, Alex K; Horsman, Eric

2015-01-01

Fracturesis Jointitis is a grammatical disorder characterized by failure or inability to understand the difference between overarching and specific terms of brittle deformation features. The disorder leads to the use of the word "fracture" as a specific type of discontinuity rather than as an overarching term for mechanical breaks in rocks. This condition appears to be prevalent among groundwater practitioners working with fractured rocks. Common signs and symptoms of Fracturesis Jointitis include the use of terms such as "joints and fractures" and "joints, faults and fractures" when describing fractures in rocks. At best, such terms imply that a "fracture" is one of many kinds of features like joints and faults, and at worst that joints and faults are not fractures but something else. Using proper terms to identify specific fracture types is critical because fractures may act as either barriers to groundwater flow (e.g., faults or deformation bands) or conduits for flow (e.g., faults and joints), The treatment for Fracturesis Jointitis involves an education campaign highlighting to the groundwater community the different fracture types that exist, the modes by which fractures propagate and the role that these fractures play in facilitating or hindering groundwater flow. Those afflicted by Fracturesis Jointitis can be cured of the condition by avoiding the word "fractures" in phrases such as "joints and fractures" or by adding descriptive words before the word "fractures" to specify fracture types (e.g., "foliation-parallel" fractures). Only with a concerted education campaign can we rid our community of Fracturesis Jointitis. © 2014, National Ground Water Association.

Real frequency of ordinary and atypical sub-trochanteric and diaphyseal fractures in France based on X-rays and medical file analysis.

PubMed

Beaudouin-Bazire, Constance; Dalmas, Noémie; Bourgeois, Julie; Babinet, Antoine; Anract, Philippe; Chantelot, Christophe; Farizon, Frédéric; Chopin, Florence; Briot, Karine; Roux, Christian; Cortet, Bernard; Thomas, Thierry

2013-03-01

Atypical sub-trochanteric and femoral shaft fractures have been reported in patients treated with bisphosphonates. Their incidence has been determined from registered data analysis using international codes. Therefore, the aim of our study was to estimate the real frequency of typical and atypical sub-trochanteric or diaphyseal fractures, based on radiological and clinical data compared to registered data. In the registers of three large French University Hospitals, patients identified with International Classification of Diseases, 10th Revision diagnosis codes for sub-trochanteric or diaphyseal fracture were selected. Frequencies of ordinary and atypical fractures were calculated after both registered data, radiological and clinical files analysis. Among the 4592 patients hospitalized for a femoral fracture over 5 years, 574 were identified to have had a sub-trochanteric or femoral shaft fracture. 47.7% of the sub-trochanteric and femoral shaft fractures were misclassified, predominantly in the sub-trochanteric fractures subset. 12 patients had an atypical fracture (4% of the sub-trochanteric and femoral shaft fractures) and 11 fractures presented radiological features of atypical fractures, whereas clinical files analysis revealed they were pathological or traumatic fractures. Atypical fractures frequency is very low. Because of their low frequency and the unreliability of registered databases, the risk of atypical fractures is very difficult to estimate retrospectively. A prospective study is needed to clarify the risk factors associated with these fractures. Copyright © 2012 Société française de rhumatologie. Published by Elsevier SAS. All rights reserved.

Medial joint space widening of the ankle in displaced Tillaux and Triplane fractures in children.

PubMed

Gourineni, Prasad; Gupta, Asheesh

2011-10-01

Tillaux and Triplane fractures occur in children predominantly from external rotation mechanism. We hypothesized that in displaced fractures, the talus would shift laterally along with the distal fibula and the distal tibial epiphyseal fragment increasing the medial joint space. Consecutive cases evaluated retrospectively. Level I and Level II centers. Twenty-two skeletally immature patients with 14 displaced Triplane fractures and eight displaced Tillaux fractures were evaluated for medial joint space widening. Measurement of fracture displacement and medial joint space widening before and after intervention. Thirteen Triplane and six Tillaux fractures (86%) showed medial space widening of 1 to 9 mm and equal to the amount of fracture displacement. Reduction of the fracture reduced the medial space to normal. There were no known complications. Medial space widening of the ankle may be a sign of ankle fracture displacement. Anatomic reduction of the fracture reduces the medial space and may improve the results in Tillaux and Triplane fractures.

Parameter Prediction of Hydraulic Fracture for Tight Reservoir Based on Micro-Seismic and History Matching

NASA Astrophysics Data System (ADS)

Zhang, Kai; Ma, Xiaopeng; Li, Yanlai; Wu, Haiyang; Cui, Chenyu; Zhang, Xiaoming; Zhang, Hao; Yao, Jun

Hydraulic fracturing is an important measure for the development of tight reservoirs. In order to describe the distribution of hydraulic fractures, micro-seismic diagnostic was introduced into petroleum fields. Micro-seismic events may reveal important information about static characteristics of hydraulic fracturing. However, this method is limited to reflect the distribution area of the hydraulic fractures and fails to provide specific parameters. Therefore, micro-seismic technology is integrated with history matching to predict the hydraulic fracture parameters in this paper. Micro-seismic source location is used to describe the basic shape of hydraulic fractures. After that, secondary modeling is considered to calibrate the parameters information of hydraulic fractures by using DFM (discrete fracture model) and history matching method. In consideration of fractal feature of hydraulic fracture, fractal fracture network model is established to evaluate this method in numerical experiment. The results clearly show the effectiveness of the proposed approach to estimate the parameters of hydraulic fractures.

Simulation of Hydraulic and Natural Fracture Interaction Using a Coupled DFN-DEM Model

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

Zhou, J.; Huang, H.; Deo, M.

2016-03-01

The presence of natural fractures will usually result in a complex fracture network due to the interactions between hydraulic and natural fracture. The reactivation of natural fractures can generally provide additional flow paths from formation to wellbore which play a crucial role in improving the hydrocarbon recovery in these ultra-low permeability reservoir. Thus, accurate description of the geometry of discrete fractures and bedding is highly desired for accurate flow and production predictions. Compared to conventional continuum models that implicitly represent the discrete feature, Discrete Fracture Network (DFN) models could realistically model the connectivity of discontinuities at both reservoir scale andmore » well scale. In this work, a new hybrid numerical model that couples Discrete Fracture Network (DFN) and Dual-Lattice Discrete Element Method (DL-DEM) is proposed to investigate the interaction between hydraulic fracture and natural fractures. Based on the proposed model, the effects of natural fracture orientation, density and injection properties on hydraulic-natural fractures interaction are investigated.« less

Simulation of Hydraulic and Natural Fracture Interaction Using a Coupled DFN-DEM Model

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

J. Zhou; H. Huang; M. Deo

The presence of natural fractures will usually result in a complex fracture network due to the interactions between hydraulic and natural fracture. The reactivation of natural fractures can generally provide additional flow paths from formation to wellbore which play a crucial role in improving the hydrocarbon recovery in these ultra-low permeability reservoir. Thus, accurate description of the geometry of discrete fractures and bedding is highly desired for accurate flow and production predictions. Compared to conventional continuum models that implicitly represent the discrete feature, Discrete Fracture Network (DFN) models could realistically model the connectivity of discontinuities at both reservoir scale andmore » well scale. In this work, a new hybrid numerical model that couples Discrete Fracture Network (DFN) and Dual-Lattice Discrete Element Method (DL-DEM) is proposed to investigate the interaction between hydraulic fracture and natural fractures. Based on the proposed model, the effects of natural fracture orientation, density and injection properties on hydraulic-natural fractures interaction are investigated.« less

Patterns of Pediatric Mandible Fractures in the United States.

PubMed

Owusu, James A; Bellile, Emily; Moyer, Jeffrey S; Sidman, James D

2016-01-01

The mandible is arguably the most frequently fractured facial bone in children. However, facial fractures are rare in children compared with adults, resulting in few large studies on patterns of pediatric facial fractures. To report the patterns, demographics, and cause of pediatric mandible fractures across the United States. A retrospective analysis was conducted of the Healthcare Cost and Utilization Project's National Emergency Department Sample from January 1 to December 31, 2012, using the International Classification of Disease, Ninth Revision, codes for mandible fractures (802.20-802.39) among patients 18 years and younger who presented to emergency departments. Demographics, fracture site, and fracture mechanism were analyzed to identify factors associated with fractures. Analysis was conducted from July 9 to July 28, 2015. There were 1984 records, representing a weighted estimate of 8848 cases of pediatric mandible fracture. The mean patient age was 14.0 years (95% CI, 13.6-14.3). The male to female ratio was 4:1 and females were comparatively younger, with a mean age of 12.5 years (95% CI, 11.8-13.1; P < .001). The most frequently fractured sites were the condyle, in 1288 patients (14.6% [95% CI, 12.6%-16.5%]), and the angle, in 1252 patients (14.1% [12.4%-15.9%]). Associated intracranial injuries occurred in 756 patients (8.5% [7.1%-10.0%]), and cervical spine fractures occurred in 393 (4.4% [3.5%-5.4%]). The fracture site and mechanism of injury varied with age and sex. For patients 12 years and younger, the most frequent fracture site was the condyle, accounting for 636 fractures (27.9% [24.2%-31.6%]), and the most frequent cause was falls, accounting for 692 fractures (30.3% [25.9%-34.8%]). In teenaged patients (13-18 years), the angle was the most frequent fracture site, accounting for 1157 fractures (17.6% [15.6%-19.6%]), and the most frequent cause was assault, accounting for 2619 fractures (39.9% [36.4%-43.3%]). For male patients, the angle was the predominant site, accounting for 1053 fractures (15.0% [13.1%-16.8%]), and the leading cause was assault, accounting for 2360 fractures (33.5% [30.2%-36.9%]). For female patients, the condyle was the most frequent site, accounting for 369 fractures (20.3% [16.0%-24.6%]), and the leading cause was falls, accounting for 422 fractures (23.2% [18.6%-28.0%]). In this study, age and sex disparities among pediatric mandible fractures were identified. Younger patients and female patients tend to have condyle fractures caused more commonly by falls while older patients and male patients tend to have angle fractures caused by assault. NA.

Origin of Permeability and Structure of Flows in Fractured Media

NASA Astrophysics Data System (ADS)

De Dreuzy, J.; Darcel, C.; Davy, P.; Erhel, J.; Le Goc, R.; Maillot, J.; Meheust, Y.; Pichot, G.; Poirriez, B.

2013-12-01

After more than three decades of research, flows in fractured media have been shown to result from multi-scale geological structures. Flows result non-exclusively from the damage zone of the large faults, from the percolation within denser networks of smaller fractures, from the aperture heterogeneity within the fracture planes and from some remaining permeability within the matrix. While the effect of each of these causes has been studied independently, global assessments of the main determinisms is still needed. We propose a general approach to determine the geological structures responsible for flows, their permeability and their organization based on field data and numerical modeling [de Dreuzy et al., 2012b]. Multi-scale synthetic networks are reconstructed from field data and simplified mechanical modeling [Davy et al., 2010]. High-performance numerical methods are developed to comply with the specificities of the geometry and physical properties of the fractured media [Pichot et al., 2010; Pichot et al., 2012]. And, based on a large Monte-Carlo sampling, we determine the key determinisms of fractured permeability and flows (Figure). We illustrate our approach on the respective influence of fracture apertures and fracture correlation patterns at large scale. We show the potential role of fracture intersections, so far overlooked between the fracture and the network scales. We also demonstrate how fracture correlations reduce the bulk fracture permeability. Using this analysis, we highlight the need for more specific in-situ characterization of fracture flow structures. Fracture modeling and characterization are necessary to meet the new requirements of a growing number of applications where fractures appear both as potential advantages to enhance permeability and drawbacks for safety, e.g. in energy storage, stimulated geothermal energy and non-conventional gas productions. References Davy, P., et al. (2010), A likely universal model of fracture scaling and its consequence for crustal hydromechanics, Journal of Geophysical Research-Solid Earth, 115, 13. de Dreuzy, J.-R., et al. (2012a), Influence of fracture scale heterogeneity on the flow properties of three-dimensional Discrete Fracture Networks (DFN), J. Geophys. Res.-Earth Surf., 117(B11207), 21 PP. de Dreuzy, J.-R., et al. (2012b), Synthetic benchmark for modeling flow in 3D fractured media, Computers and Geosciences(0). Pichot, G., et al. (2010), A Mixed Hybrid Mortar Method for solving flow in Discrete Fracture Networks, Applicable Analysis, 89(10), 1729-1643. Pichot, G., et al. (2012), Flow simulation in 3D multi-scale fractured networks using non-matching meshes, SIAM Journal on Scientific Computing (SISC), 34(1). Figure: (a) Fracture network with a broad-range of fracture lengths. (b) Flows (log-scale) with homogeneous fractures. (c) Flows (log-scale) with heterogeneous fractures [de Dreuzy et al., 2012a]. The impact of the fracture apertures (c) is illustrated on the organization of flows.

Spontaneous passage of long, sharp gastrointestinal foreign body in a child.

PubMed

Karthikeyan, Vilvapathy Senguttuvan; Ansari, Mohammed Gaffoor; Suresh, Ramasamy; Easwaran, Bettaiyagowder

2015-01-19

Foreign body (FB) ingestion is a common problem in children. Up to 90% of these FBs pass spontaneously. FBs reaching the stomach usually pass out spontaneously. Exceptions to this spontaneous passage include a long FB that cannot cross the pylorus, duodenum or ileocaecal junction. We present a case of a 9-year boy who accidentally ingested a long paper pin, which spontaneously passed in 26 h. This case is being reported to highlight the successful spontaneous passage of a 4 cm long sharp foreign body in a child. 2015 BMJ Publishing Group Ltd.

Phorbol ester and spontaneous activity in SHR aorta

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

Moisey, D.M.; Cox, R.H.

1986-03-01

Thoracic aortas (TA) were excised from 6-week old SHR and WKY. 2mm rings were mounted isometrically at optimum preload. Spontaneous rhythmical activity developed in TA from SHR and had a frequency of 3-4/min with varying periods of quiescence between bursts of activity. The spontaneous activity often produced an increase in tension development which was associated with increased frequency of oscillations. Verapamil (10/sup -7/ M) or Ca/sup + +/-free solution added during the contractile phase resulted in an immediate loss of tension and spontaneous activity. Addition of ouabain (10/sup -4/ M) during the contractile phase of spontaneous activity, increased the frequencymore » of oscillations which appeared to fuse into a tetanus. Spontaneous rhythmical activity was infrequently observed in TA from WKY. However, addition of phorbol 12-myristate-13 acetate (TPA), frequently induced spontaneous rhythmic oscillations associated with tension development in TA from WKY. TPA contracted the SHR TA and increased the frequency of oscillations. SHR TA were more sensitive to TPA than WKY. This study demonstrates (1) spontaneous rhythmical activity, independent of agonist stimulation in TA from 6-week old SHR and (2) TPA induced spontaneous oscillatory activity. The mechanism underlying the spontaneous oscillatory activity may involve membrane coupling events and Na-pump difference between SHR and WKY.« less

Tooth display and lip position during spontaneous and posed smiling in adults.

PubMed

Van Der Geld, Pieter; Oosterveld, Paul; Berge, Stefaan J; Kuijpers-Jagtman, Anne M

2008-08-01

To analyze differences in tooth display, lip-line height, and smile width between the posed smiling record, traditionally produced for orthodontic diagnosis, and the spontaneous (Duchenne) smile of joy. The faces of 122 male participants were each filmed during spontaneous and posed smiling. Spontaneous smiles were elicited through the participants watching a comical movie. Maxillary and mandibular lip-line heights, tooth display, and smile width were measured using a digital videographic method for smile analysis. Paired sample t-tests were used to compare measurements of posed and spontaneous smiling. Maxillary lip-line heights during spontaneous smiling were significantly higher than during posed smiling. Compared to spontaneous smiling, tooth display in the (pre)molar area during posed smiling decreased by up to 30%, along with a significant reduction of smile width. During posed smiling, also mandibular lip-line heights changed and the teeth were more covered by the lower lip than during spontaneous smiling. Reduced lip-line heights, tooth display, and smile width on a posed smiling record can have implications for the diagnostics of lip-line height, smile arc, buccal corridors, and plane of occlusion. Spontaneous smiling records next to posed smiling records are therefore recommended for diagnostic purposes. Because of the dynamic nature of spontaneous smiling, it is proposed to switch to dynamic video recording of the smile.

Extending Topological Approaches to Microseismic-Derived 3D Fracture Networks

NASA Astrophysics Data System (ADS)

Urbancic, T.; Bosman, K.; Baig, A.; Ardakani, E. P.

2017-12-01

Fracture topology is important for determining the fluid-flow characteristics of a fracture network. In most unconventional petroleum applications, flow through subsurface fracture networks is the primary source of production, as matrix permeability is often in the nanodarcy range. Typical models of reservoir discrete fracture networks (DFNs) are constructed using fracture orientation and average spacing, without consideration of how the connectivity of the fracture network aids the percolation of hydrocarbons back to the wellbore. Topological approaches to DFN characterization have been developed and extensively used in analysis of outcrop data and aerial photography. Such study of the surface expression of fracture networks is straight-forward, and the physical form of the observed fractures is directly reflected in the parameters used to describe the topology. However, this analysis largely ignores the three-dimensional nature of natural fracture networks, which is difficult to define accurately in geological studies. SMTI analysis of microseismic event distributions can produce DFNs, where each event is represented by a penny-shaped crack with radius and orientation determined from the frequency content of the waveforms and assessment of the slip instability of the potential fracture planes, respectively. Analysis of the geometric relationships between a set of fractures can provide details of intersections between fractures, and thus the topological characteristics of the fracture network. Extension of existing 2D topology approaches to 3D fracture networks is non-trivial. In the 2D case, a fracture intersection is a single point (node), and branches connect adjacent nodes along fractures. For the 3D case, intersection "nodes" become lines, and connecting nodes to find branches becomes more complicated. There are several parameters defined in 2D topology to quantify the connectivity of the fracture network. Equivalent quantities must be defined and calibrated for the 3D case to provide a meaningful measurement of fracture network connectivity. We have developed an approach to analyze the topology of 3D fracture networks derived from microseismic moment tensors. We illustrate the utility of the approach with applications to example datasets from hydraulic fracturing completions.

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

Ahmad Ghassemi

Geothermal energy is recovered by circulating water through heat exchange areas within a hot rock mass. Geothermal reservoir rock masses generally consist of igneous and metamorphic rocks that have low matrix permeability. Therefore, cracks and fractures play a significant role in extraction of geothermal energy by providing the major pathways for fluid flow and heat exchange. Therefore, knowledge of the conditions leading to formation of fractures and fracture networks is of paramount importance. Furthermore, in the absence of natural fractures or adequate connectivity, artificial fractures are created in the reservoir using hydraulic fracturing. Multiple fractures are preferred because of themore » large size necessary when using only a single fracture. Although the basic idea is rather simple, hydraulic fracturing is a complex process involving interactions of high pressure fluid injections with a stressed hot rock mass, mechanical interaction of induced fractures with existing natural fractures, and the spatial and temporal variations of in-situ stress. As a result, it is necessary to develop tools that can be used to study these interactions as an integral part of a comprehensive approach to geothermal reservoir development, particularly enhanced geothermal systems. In response to this need we have developed advanced poro-thermo-chemo-mechanical fracture models for rock fracture research in support of EGS design. The fracture propagation models are based on a regular displacement discontinuity formulation. The fracture propagation studies include modeling interaction of induced fractures. In addition to the fracture propagation studies, two-dimensional solution algorithms have been developed and used to estimate the impact of pro-thermo-chemical processes on fracture permeability and reservoir pressure. Fracture permeability variation is studied using a coupled thermo-chemical model with quartz reaction kinetics. The model is applied to study quartz precipitation/dissolution, as well as the variation in fracture aperture and pressure. Also, a three-dimensional model of injection/extraction has been developed to consider the impact poro- and thermoelastic stresses on fracture slip and injection pressure. These investigations shed light on the processes involved in the observed phenomenon of injection pressure variation (e.g., in Coso), and allow the assessment of the potential of thermal and chemical stimulation strategies.« less

[Anatomy of fractures of the inferior scapular angle].

PubMed

Bartoníček, J; Tuček, M; Malík, J

2018-01-01

The aim of this study is to describe the anatomy of fractures of the inferior angle and the adjacent part of the scapular body, based on 3D CT reconstructions. In a series of 375 scapular fractures, we identified a total of 20 fractures of the inferior angle of the scapular body (13 men, 7 women), with a mean patient age of 50 years (range 3373). In all fractures, 3D CT reconstructions were obtained, allowing an objective evaluation of the fracture pattern with a focus on the size and shape of the inferior angle fragment, propagation of the fracture line to the lateral and medial borders of the infraspinous part of the scapular body, fragment displacement and any additional fracture of the ipsilateral scapula and the shoulder girdle. We identified a total of 5 types of fracture involving the distal half of the infraspinous part of the scapular body. The first type, recorded in 5 cases, affected only the apex of the inferior angle, with a small part of the adjacent medial border. The second type, occurring in 4 cases, involved fractures separating the entire inferior angle. The third type, represented by 4 cases, was characterized by a fracture line starting medially close above the inferior angle and passing proximolaterally. The separated fragment had a shape of a big drop, carrying also the distal half of the lateral pillar in addition to the inferior angle. In the fourth type identified in 5 fractures, the separated fragment was formed both by the inferior angle and a variable part of the medial border. The fifth type, being by its nature a transition to the fracture of the infraspinous part of the body, was recorded in 2 cases, with the same V-shaped fragment. Fractures of the inferior angle and the adjacent part of the scapular body are groups of fractures differing from other infraspinous fractures of the scapular body. Although these fractures are highly variable in terms of shape, they have the same course of fracture line and the manner of displacement.Key words: scapula scapula fractures scapular body fractures inferior angle classification of scapular body fractures.

Identification and characterisation of individual Fractures in 3D fracture-network of shale reservoir rocks from microtomography

NASA Astrophysics Data System (ADS)

Qi, C.; Liu, J.

2017-12-01

Fractures are essential for unconventional hydrocarbon production. However, the observation of fractures in three-dimensional (3D) space is very difficult except using microtomography to obtain 3D fracture structures at micro-scales. Twelve shale samples taken from a specimen are analyzed in this study: six of them were isobarically and five were isothermally processed in experiments of simulating hydrocarbon generation and expulsion and one is unprocessed. The resolutions of microtomographic images are in the range from 5.83 to 9.12 μm. Fractures developed in different complexities: some samples have mostly parallel fractures, some have major parallel fractures plus irregular fractures forming crack-network and some samples have fully intersected fractures of various directions. To identify individual fractures in 3D network is crucial for the characterization of fractures and it needs to separate each fractures or disconnect intersections of fractures. For those samples with fewer intersections, it is not difficult to disconnect intersections manually slice by slice using Avizo®. For those samples with complex intersections, it is impractical to process manually. A patented method and corresponding programs are used to separate, identify and characterize individual fractures. By procedures of filtering, smoothing, thinning, separating and combining, intersected cracks are separated, the segments of a broken elongated cracks are identified as one crack, and the thinned thickness is restored, finally the shape, orientation and dimensions of individual fractures are characterized. Our results show that: 1) relatively large fractures are very thin, showing typical fracture morphology, while small fractures may have various shapes; 2) isothermal processed samples have stronger anisotropy, which implies that the fractures in isothermal series are thinner or flatter than in isobaric series; 3) the fractal dimension exists in the samples and there is good correlation between the fractal dimension and temperature/pressure. This study is a first trial of the characterization of individual cracks in 3D network. It lays a foundation for future research on the prediction of large-scale fractures in tight reservoirs.

The causes and prognoses of different types of fractures in wild koalas submitted to wildlife hospitals.

PubMed

Henning, Joerg; Hannon, Christabel; McKinnon, Allan; Larkin, Rebecca; Allavena, Rachel

2015-12-01

Fractures are a major problem in wild koalas of great veterinary and conservation importance as their occurrence in different locations of the body might result in varying healing success. The aim of this study was to determine the fracture types (defined by location of the fracture) occurring in wild koalas, temporal patterns, possible causes and risk factors of fracture types, and the prognosis for successfully releasing kolas with healed fracture types into the wild. Data from a total of 2031 wild koalas submitted to wildlife hospitals in South-East Queensland, Australia, over a period of 13 years were analysed. Approximately 56.7% of koalas experienced head fractures, 13.4% had torso fractures, 14.9% had limb fractures and 15% had combination fractures. A total of 84.1% of fractures were caused by vehicle collisions, 9.1% by dog attacks, 3.3% by falls from trees, 1.3% by train collisions, 0.2% by livestock trampling and 1.8% due to unknown causes. Multinominal logistic regression was used to identify risk factors (cause of fracture, age category, sex, year, three-year admission period and season of fracture event) by fracture type. The type of fracture was associated with both the cause of the fracture and the season when it occurred: for example torso fractures (compared to combination fractures) were associated with dog attacks (OR=10.98; 95% CI6.03, 20.01) and falls from trees (OR=4.79; 95% CI2.26, 10.19) relative to vehicle collisions. More submissions of koalas with head fractures due to vehicle collisions occurred in spring compared to autumn and winter, coinciding with the breeding season of koalas and increased animal movement. Prognosis for koalas with fractures was poor, with approximately 63.8% of koalas admitted dead on arrival, 34.2% euthanised, and only 2.0% of koalas able to be released. Given this data, further research into mitigation strategies to decrease the risk of fractures and to increase the observed low recovery rate should be considered. Copyright © 2015 Elsevier B.V. All rights reserved.

A Distal Forearm Fracture in Childhood Is Associated With an Increased Risk for Future Fragility Fractures in Adult Men, but Not Women

PubMed Central

Amin, Shreyasee; Melton, L Joseph; Achenbach, Sara J; Atkinson, Elizabeth J; Dekutoski, Mark B; Kirmani, Salman; Fischer, Philip R; Khosla, Sundeep

2014-01-01

Distal forearm fractures are among the most common fractures during childhood, but it remains unclear whether they predict an increased fracture risk later in life. We studied a population-based cohort of 1776 children ≤18 years of age, from Olmsted County, MN, USA, who had a distal forearm fracture in 1935–1992. Incident fractures occurring at age ≥35 years were identified through review of complete medical records using the linkage system of the Rochester Epidemiology Project. Observed nonpathologic fractures resulting from no more than moderate trauma (fragility fractures) were compared with expected numbers estimated from fracture site–specific incidence rates, based on age, sex, and calendar year, for Olmsted County (standardized incidence ratios [SIR]). In 1086 boys (mean ± SD age; 11 ± 4 years) and 690 girls (10 ± 4 years) followed for 27,292 person-years after the age of 35 years, subsequent fragility fractures were observed in 144 (13%) men and 74 (11%) women. There was an increased risk for future fragility fractures in boys who had a distal forearm fracture (SIR, 1.9; 95% CI, 1.6–2.3) but not girls (SIR, 1.0; 95% CI, 0.8–1.2). Fragility fractures at both major osteoporotic (hip, spine, wrist, and shoulder) sites (SIR, 2.6; 95% CI, 2.1–3.3) and remaining sites (SIR, 1.7; 95% CI, 1.3–2.0) were increased in men, irrespective of age at distal forearm fracture as boys. A distal forearm fracture in boys, but not girls, is associated with an increased risk for fragility fractures as older adults. It is necessary to determine whether the increased fractures observed in men is due to persistent deficits of bone strength, continued high fracture risk activity, or both. Until then, men should be asked about a childhood distal forearm fracture and, if so, warrant further screening and counseling on measures to optimize bone health and prevent fractures. PMID:23456800

Influence of Natural Fractures Cohesive Properties on Geometry of Hydraulic Fracture Networks

NASA Astrophysics Data System (ADS)

Gonzalez-Chavez, M. A.; Dahi Taleghani, A.; Puyang, P.

2014-12-01

An integrated modeling methodology is proposed to analyze hydraulic fracturing jobs in the presence of the natural fracture network in the formation. A propagating hydraulic fracture may arrest, cross, or diverts into a preexisting natural crack depending on fracture properties of rock and magnitude and direction of principal rock stresses. Opening of natural fractures during fracturing treatment could define the effectiveness of the stimulation technique. Here, we present an integrated methodology initiated with lab scale fracturing properties using Double Cantilever Beam tests (DCB) to determine cohesive properties of rock and natural fractures. We used cohesive finite element models to reproduce laboratory results to verify the numerical model for the interaction of the hydraulic fracture and individual cemented natural fractures. Based on the initial investigations, we found out that distribution of pre-existing natural fractures could play a significant role in the final geometry of the induced fracture network; however in practice, there is not much information about the distribution of natural fractures in the subsurface due to the limited access. Hence, we propose a special optimization scheme to generate natural fracture geometry from the location of microseismic events. Accordingly, the criteria of evaluating the fitness of natural fracture realizations is defined as the total minimum distance squares of all microseismic events, which is the sum of minimum square distance for all microseismic events. Moreover, an additional constraint in this problem is that we need to set a minimum distance between fracture grids. Using generated natural fracture realizations, forward field-scale simulations are implemented using cohesive finite element analysis to find the best match with the recorded bottomhole pressure. To show the robustness of the proposed workflow for real field problem, we implemented this technique on available data from several well Chicontepec basin to forecast post-treatment production rate. Our results show a constructive approach to integrate microseismic maps with lab mechanical measurements and bottomhole pressure to estimate the geometry of induced fracture network in the subsurface which does not suffer from any limiting assumption about fracture geometries.

High revision rate but good healing capacity of atypical femoral fractures. A comparison with common shaft fractures.

PubMed

Schilcher, Jörg

2015-12-01

Healing of complete, atypical femoral fractures is thought to be impaired, but the evidence is weak and appears to be based on the delayed healing observed in patients with incomplete atypical fractures. Time until fracture healing is difficult to assess, therefore we compared the reoperation rates between women with complete atypical femoral fractures and common femoral shaft fractures. We searched the orthopaedic surgical registry in Östergötland County for patients with subtrochanteric and femoral shaft fractures (ICD-10 diagnosis codes S72.2, S72.3 and M84.3F) between January 1st 2007 and December 31st 2013. Out of 895 patients with surgically treated femoral shaft fractures, 511 were women 50 years of age or older. Among these we identified 24 women with atypical femoral shaft fractures, and 71 with common shaft fractures. Reoperations were performed in 6 and 5 patients, respectively, odds ratio 4.4 (95% CI 1.2 to 16.1). However, 5 reoperations in the atypical fracture group could not be ascribed to poor healing. In 3 patients the reoperation was due to a new fracture proximal to a standard intramedullary nail. In 2 patients the distal locking screws were removed due to callus formation that was deemed incomplete 5 months post-operatively. The one patient with poor healing showed faint callus formation at 5 months when the fracture was dynamised and callus remained sparse at 11 months. Among patients with common shaft fractures, 2 reoperations were performed to remove loose screws, 2 because of peri-implant fractures and 1 reoperation due to infection. Reoperation rates in patients with complete atypical femoral fractures are higher than in patients with common shaft fractures. The main reason for failure was peri-implant fragility fractures which might be prevented with the use of cephalomedullary nails at the index surgery. Fracture healing however, seems generally good. A watchful waiting approach is advocated in patients with fractures that appear to heal slowly. Copyright © 2015 Elsevier Ltd. All rights reserved.

Distal Fibula Fractures in National Football League Athletes.

PubMed

Werner, Brian C; Mack, Christina; Franke, Kristina; Barnes, Ronnie P; Warren, Russell F; Rodeo, Scott A

2017-09-01

Despite the frequency of distal fibula fractures in elite athletes and the significant potential impact on the athletes' season and future careers, little data exist characterizing the epidemiology of these injuries or, more importantly, return to competition. To (1) evaluate the incidence of acute distal fibula fractures in National Football League (NFL) athletes, including isolated distal fibula and combined ankle fracture patterns; (2) analyze distal fibula fracture rates in NFL athletes by position, type of play, and contact type; (3) determine the rates of distal fibula fracture surgery in NFL athletes; and (4) report the days missed due to distal fibula fractures in NFL athletes. Descriptive epidemiology study. A retrospective review of distal fibula fractures reported to the NFL from 2000 to 2014 was performed using the NFL Injury Surveillance System. All distal fibula fractures were included, along with isolated and combined fracture patterns. Stress fractures and proximal fibula fractures were excluded. Epidemiological data and rates of surgery were determined. Return to sport was calculated and stratified by injury pattern and management. Overall, 237 distal fibula fractures in NFL athletes from 2000 to 2014 were included; 197 (83%) were isolated distal fibula fractures. A mean of 16 distal fibula fractures occurred each year (median, 16 per year). Fractures occurred most frequently on running (38%) and passing (24%) plays, but the frequency was next highest on kickoffs (16%), despite the relative infrequency of kickoffs during the average game compared with other play types. Surgery was reported for more than half of all distal fibula fractures (n = 128, 54%). Overall, patients who underwent surgery missed significantly more days (mean, 123.8 days) than players who did not undergo surgery (mean, 75.3 days) ( P < .001). Players with isolated distal fibula fractures had significantly fewer days missed (mean, 93.6 days) compared with those with combined patterns (mean, 132.3 days) ( P = .0004). Fibula fractures affect a number of NFL athletes and result in significant time missed from competition. Further research is required to determine the optimal management of fibula fractures in NFL athletes. In this study, time to return to play depended on both the fracture pattern and whether surgery was required and ranged from 72 to 145 days.

The subsurface impact of hydraulic fracturing in shales- Perspectives from the well and reservoir

NASA Astrophysics Data System (ADS)

ter Heege, Jan; Coles, Rhys

2017-04-01

It has been identified that the main risks of subsurface shale gas operations in the U.S.A. and Canada are associated with (1) drilling and well integrity, (2) hydraulic fracturing, and (3) induced seismicity. Although it is unlikely that hydraulic fracturing operations result in direct pathways of enhanced migration between stimulated fracture disturbed rock volume and shallow aquifers, operations may jeopardize well integrity or induce seismicity. From the well perspective, it is often assumed that fluid injection leads to the initiation of tensile (mode I) fractures at different perforation intervals along the horizontal sections of shale gas wells if pore pressure exceeds the minimum principal stress. From the reservoir perspective, rise in pore pressure resulting from fluid injection may lead to initiation of tensile fractures, reactivation of shear (mode II) fractures if the criterion for failure in shear is exceeded, or combinations of different fracturing modes. In this study, we compare tensile fracturing simulations using conventional well-based models with shear fracturing simulations using a fractured shale model with characteristic fault populations. In the fractured shale model, stimulated permeability is described by an analytical model that incorporates populations of reactivated faults and that combines 3D permeability tensors for layered shale matrix, damage zone and fault core. Well-based models applied to wells crosscutting the Posidonia Shale Formation are compared to generic fractured shale models, and fractured shale models are compared to micro-seismic data from the Marcellus Shale. Focus is on comparing the spatial distribution of permeability, stimulated reservoir volume and seismicity, and on differences in fracture initiation pressure and fracture orientation for tensile and shear fracturing end-members. It is shown that incorporation of fault populations (for example resulting from analysis of 3D seismics or outcrops) in hydraulic fracturing models provides better constraints on well pressures, stimulated fracture disturbed volume and induced seismicity. Thereby, it helps assessing the subsurface impact of hydraulic fracturing in shales and mitigating risks associated with loss of loss of well integrity, loss of fracture containment, and induced seismicity.

Finite element modeling of the influence of hand position and bone properties on the Colles' fracture load during a fall.

PubMed

Buchanan, Drew; Ural, Ani

2010-08-01

Distal forearm fracture is one of the most frequently observed osteoporotic fractures, which may occur as a result of low energy falls such as falls from a standing height and may be linked to the osteoporotic nature of the bone, especially in the elderly. In order to prevent the occurrence of radius fractures and their adverse outcomes, understanding the effect of both extrinsic and intrinsic contributors to fracture risk is essential. In this study, a nonlinear fracture mechanics-based finite element model is applied to human radius to assess the influence of extrinsic factors (load orientation and load distribution between scaphoid and lunate) and intrinsic bone properties (age-related changes in fracture properties and bone geometry) on the Colles' fracture load. Seven three-dimensional finite element models of radius were created, and the fracture loads were determined by using cohesive finite element modeling, which explicitly represented the crack and the fracture process zone behavior. The simulation results showed that the load direction with respect to the longitudinal and dorsal axes of the radius influenced the fracture load. The fracture load increased with larger angles between the resultant load and the dorsal axis, and with smaller angles between the resultant load and longitudinal axis. The fracture load also varied as a function of the load ratio between the lunate and scaphoid, however, not as drastically as with the load orientation. The fracture load decreased as the load ratio (lunate/scaphoid) increased. Multiple regression analysis showed that the bone geometry and the load orientation are the most important variables that contribute to the prediction of the fracture load. The findings in this study establish a robust computational fracture risk assessment method that combines the effects of intrinsic properties of bone with extrinsic factors associated with a fall, and may be elemental in the identification of high fracture risk individuals as well as in the development of fracture prevention methods including protective falling techniques. The additional information that this study brings to fracture identification and prevention highlights the promise of fracture mechanics-based finite element modeling in fracture risk assessment.

Multifocal humeral fractures.

PubMed

Maresca, A; Pascarella, R; Bettuzzi, C; Amendola, L; Politano, R; Fantasia, R; Del Torto, M

2014-02-01

Multifocal humeral fractures are extremely rare. These may affect the neck and the shaft, the shaft alone, or the diaphysis and the distal humerus. There is no classification of these fractures in the literature. From 2004 to 2010, 717 patients with humeral fracture were treated surgically at our department. Thirty-five patients presented with an associated fracture of the proximal and diaphyseal humerus: synthesis was performed with plate and screws in 34 patients, and the remaining patient had an open fracture that was treated with an external fixator. Mean follow-up was 3 years and 3 months. A classification is proposed in which type A fractures are those affecting the proximal and the humeral shaft, type B the diaphysis alone, and type C the diaphysis in association with the distal humerus. Type A fractures are then divided into three subgroups: A-I, undisplaced fracture of the proximal humerus and displaced shaft fracture; A-II: displaced fracture of the proximal and humeral shaft; and A-III: multifragmentary fracture affecting the proximal humerus and extending to the diaphysis. Multifocal humeral fractures are very rare and little described in the literature, both for classification and treatment. The AO classification describes bifocal fracture of the humeral diaphysis, type B and C. The classification suggested in this article mainly concerns fractures involving the proximal and humeral shaft. A simple classification of multifocal fractures is suggested to help the surgeon choose the most suitable type of synthesis for surgical treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

A discrete fracture model for two-phase flow in fractured porous media

NASA Astrophysics Data System (ADS)

Gläser, Dennis; Helmig, Rainer; Flemisch, Bernd; Class, Holger

2017-12-01

A discrete fracture model on the basis of a cell-centered finite volume scheme with multi-point flux approximation (MPFA) is presented. The fractures are included in a d-dimensional computational domain as (d - 1)-dimensional entities living on the element facets, which requires the grid to have the element facets aligned with the fracture geometries. However, the approach overcomes the problem of small cells inside the fractures when compared to equi-dimensional models. The system of equations considered is solved on both the matrix and the fracture domain, where on the prior the fractures are treated as interior boundaries and on the latter the exchange term between fracture and matrix appears as an additional source/sink. This exchange term is represented by the matrix-fracture fluxes, computed as functions of the unknowns in both domains by applying adequate modifications to the MPFA scheme. The method is applicable to both low-permeable as well as highly conductive fractures. The quality of the results obtained by the discrete fracture model is studied by comparison to an equi-dimensional discretization on a simple geometry for both single- and two-phase flow. For the case of two-phase flow in a highly conductive fracture, good agreement in the solution and in the matrix-fracture transfer fluxes could be observed, while for a low-permeable fracture the discrepancies were more pronounced. The method is then applied two-phase flow through a realistic fracture network in two and three dimensions.

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°.

Risk of fractures in an intermediate care facility for persons with mental retardation.

PubMed

Tannenbaum, T N; Lipworth, L; Baker, S

1989-01-01

The epidemiology of fractures among 553 residents of an intermediate care facility for persons with mental retardation was examined. In a 10-month period, 61 fractures occurred among 55 residents; application of fracture rates in the United States revealed an expected number of 15 fractures among the 553 residents, p less than .001. Although 52% of fractures involved small bones of the hands and feet, elderly residents were more likely to fracture major bones and to suffer their fractures from a fall than were younger residents. The relationship between potential risk factors and fracture risk were examined and implications for preventive and rehabilitative measures discussed.

Fracture mechanics; Proceedings of the 22nd National Symposium, Atlanta, GA, June 26-28, 1990. Vols. 1 & 2

NASA Technical Reports Server (NTRS)

Ernst, Hugo A. (Editor); Saxena, Ashok (Editor); Mcdowell, David L. (Editor); Atluri, Satya N. (Editor); Newman, James C., Jr. (Editor); Raju, Ivatury S. (Editor); Epstein, Jonathan S. (Editor)

1992-01-01

Current research on fracture mechanics is reviewed, focusing on ductile fracture; high-temperature and time-dependent fracture; 3D problems; interface fracture; microstructural aspects of fatigue and fracture; and fracture predictions and applications. Particular attention is given to the determination and comparison of crack resistance curves from wide plates and fracture mechanics specimens; a relationship between R-curves in contained and uncontained yield; the creep crack growth behavior of titanium alloy Ti-6242; a crack growth response in three heat resistant materials at elevated temperature; a crack-surface-contact model for determining effective-stress-intensity factors; interfacial dislocations in anisotropic bimaterials; an effect of intergranular crack branching on fracture toughness evaluation; the fracture toughness behavior of exservice chromium-molybdenum steels; the application of fracture mechanics to assess the significance of proof loading; and a load ratio method for estimating crack extension.

Onset of density-driven instabilities in fractured aquifers

NASA Astrophysics Data System (ADS)

Jafari Raad, Seyed Mostafa; Hassanzadeh, Hassan

2018-04-01

Linear stability analysis is conducted to study the onset of density-driven convection involved in solubility trapping of C O2 in fractured aquifers. The effect of physical properties of a fracture network on the stability of a diffusive boundary layer in a saturated fractured porous media is investigated using the dual porosity concept. Linear stability analysis results show that both fracture interporosity flow and fracture storativity play an important role in the stability behavior of the system. It is shown that a diffusive boundary layer under the gravity field in fractured porous media with lower fracture storativity and/or higher fracture interporosity flow coefficient is more stable. We present scaling relations for the onset of convective instability in fractured aquifers with single and variable matrix block size distribution. These findings improve our understanding of density-driven flow in fractured aquifers and are important in the estimation of potential storage capacity, risk assessment, and storage site characterization and screening.

[Fractures of the proximal interphalangeal joint: Diagnostic and operative therapy options].

PubMed

Unglaub, F; Langer, M F; Hahn, P; Müller, L P; Ahrens, C; Spies, C K

2016-02-01

Joint fractures of the fingers often entail operative interventions in contrast to extra-articular fractures. These types of fracture are inclined to dislocate in addition to the actual fracture. The proximal interphalangeal (PIP) joint in particular often shows comminuted fractures due to the long leverage of the finger and a relatively small diameter of the joint. The clinical examination, X-ray diagnostics and if necessary computed tomography allow the classification into stable and unstable fractures. Unstable fractures must be treated by surgical reduction and fixation. A multitude of operative techniques are available for these mostly complicated fractures. The foremost goal is a stable osteosynthesis of the fracture with repositioning of the dislocation, which enables early physiotherapy in order to prevent tendon adhesion and contracture. This article presents the different types of PIP joint fractures, their specific surgical treatment and postoperative treatment regimens.

Self-Organizing Fluid Convection Patterns in an en Echelon Fault Array

NASA Astrophysics Data System (ADS)

Patterson, James W.; Driesner, Thomas; Matthai, Stephan K.

2018-05-01

We present three-dimensional numerical simulations of natural convection in buried, vertical en echelon faults in impermeable host rock. Despite the fractures being hydraulically disconnected, convection within each fracture alters the temperature field in the surrounding host rock, altering convection in neighboring fractures. This leads to self-organization of coherent patterns of upward/downward flow and heating/cooling of the host rock spanning the entire fault array. This "synchronization" effect occurs when fracture spacing is less than the width of convection cells within the fractures, which is controlled by fracture transmissivity (permeability times thickness) and heterogeneity. Narrow fracture spacing and synchronization enhance convective fluid flow within fractures and cause convection to initiate earlier, even lowering the critical transmissivity necessary for convection initiation. Heat flow through the en echelon region, however, is enhanced only in low-transmissivity fractures, while heat flow in high-permeability fractures is reduced due to thermal interference between fractures.

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.

Application of fracture mechanics to failure in manatee rib bone.

PubMed

Yan, Jiahau; Clifton, Kari B; Reep, Roger L; Mecholsky, John J

2006-06-01

The Florida manatee (Trichechus manatus latirostris) is listed as endangered by the U.S. Department of the Interior. Manatee ribs have different microstructure from the compact bone of other mammals. Biomechanical properties of the manatee ribs need to be better understood. Fracture toughness (K(C)) has been shown to be a good index to assess the mechanical performance of bone. Quantitative fractography can be used in concert with fracture mechanics equations to identify fracture initiating defects/cracks and to calculate the fracture toughness of bone materials. Fractography is a standard technique for analyzing fracture behavior of brittle and quasi-brittle materials. Manatee ribs are highly mineralized and fracture in a manner similar to quasi-brittle materials. Therefore, quantitative fractography was applied to determine the fracture toughness of manatee ribs. Average fracture toughness values of small flexure specimens from six different sizes of manatees ranged from 1.3 to 2.6 MPa(m)(12). Scanning electron microscope (SEM) images show most of the fracture origins were at openings for blood vessels and interlayer spaces. Quantitative fractography and fracture mechanics can be combined to estimate the fracture toughness of the material in manatee rib bone. Fracture toughness of subadult and calf manatees appears to increase as the size of the manatee increases. Average fracture toughness of the manatee rib bone materials is less than the transverse fracture toughness of human and bovine tibia and femur.

Insights from the Global Longitudinal Study of Osteoporosis in Women (GLOW).

PubMed

Watts, Nelson B

2014-07-01

GLOW is an observational, longitudinal, practice-based cohort study of osteoporosis in 60,393 women aged ≥55 years in 10 countries on three continents. In this Review, we present insights from the first 3 years of the study. Despite cost analyses being frequently based on spine and hip fractures, we found that nonvertebral, nonhip fractures were around five times more common and doubled the use of health-care resources compared with hip and spine fractures combined. Fractures not at the four so-called major sites in FRAX(®) (upper arm, forearm, hip and clinical vertebral fractures) account for >40% of all fractures. The risk of fracture is increased by various comorbidities, such as Parkinson disease, multiple sclerosis and lung and heart disease. Obesity, although thought to be protective against all fractures, substantially increased the risk of fractures in the ankle or lower leg. Simple assessment by age plus fracture history has good predictive value for all fractures, but risk profiles differ for first and subsequent fractures. Fractures diminish quality of life as much or more than diabetes mellitus, arthritis and lung disease, yet women substantially underestimate their own fracture risk. Treatment rates in patients at high risk of fracture are below those recommended but might be too frequent in women at low risk. Comorbidities and the limits of current therapeutic regimens jeopardize the efficacy of drugs; new regimens should be explored for severe cases.

Open natural fractures in sandstone at 18,300 ft: Do they help or hinder production of gas?

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

Lorenz, J.C.; Billingsley, R.L.; Evans, L.W.

1996-06-01

Vertical core, from relatively undeformed Cretaceous (Frontier FM) sandstones at a depth of 18,300 ft in the Green River Basin, contains three sets of mineralized natural fractures. The earliest fractures opened in extension as the strata passed through the hydrocarbon window. Continued subsidence and the maturation of organic material created overpressured conditions, causing oil to be injected into the fractures. Only a carbon residue of the original oil remains in these fractures, suggesting continued burial and maturation. The residue seriously inhibits permeability along and across fractures. Oil residue is also present in oblique, unmineralized mare`s-tails at the ends of fractures,more » suggesting that the in situ stress orientations had changed slightly. Quartz crystals mineralized the fracture walls, growing over the oil residue or pushing it aside. A second set of extension fractures strikes 20-30 degrees oblique to the first set. These fractures are mineralized with calcite, which was also deposited over the quartz in the first fracture set. Continued tectonism reoriented the horizontal stresses by nearly 90 degrees, forming a third set of extension fractures and further degrading permeability by narrowing apertures along earlier fractures. Significant porosity remains along many of the fractures at this depth, yet the in situ stresses and oil residue have combined to degrade fracture permeability to uneconomic matrix values.« less

Open natural fractures in sandstone at 18,300 ft: Do they help or hinder production of gas?

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

Lorenz, J.C.; Billingsley, R.L.; Evans, L.W.

1995-06-01

Vertical core, from relatively undeformed Cretaceous (Frontier Fm) sandstones at a depth of 18,300 ft in the Green River Basin, contains three sets of mineralized natural fractures. The earliest fractures opened in extension as the strata passed through the hydrocarbon window. Continued subsidence and the maturation of organic material created overpressured conditions, causing oil to be injected into the fractures. Only a carbon residue of the original oil remains in these fractures, suggesting continued burial and maturation. The residue seriously inhibits permeability along and across fractures. Oil residue is also present in oblique, unmineralized mare`s-tails at the ends of fractures,more » suggesting that the in-situ stress orientations had changed slightly. Quartz crystals mineralized the fracture walls, growing over the oil residue or pushing it aside. A second set of extension fractures strikes 20-30 degrees oblique to the first set. These fractures are mineralized with calcite, which was also deposited over the quartz in the first fracture set. Continued tectonism reoriented the horizontal stresses by nearly 90 degrees, forming a third set of extension fractures and further degrading permeability by narrowing apertures along earlier fractures. Significant porosity remains along many of the fractures at this depth, yet the in situ stresses and oil residue have combined to degrade fracture permeability to uneconomic matrix values.« less

Serum FSH level below 10 mIU/mL at twelve years old is an index of spontaneous and cyclical menstruation in Turner syndrome.

PubMed

Aso, Keiko; Koto, Shinobu; Higuchi, Asako; Ariyasu, Daisuke; Izawa, Masako; Miyamoto Igaki, Junko; Hasegawa, Yukihiro

2010-01-01

The gonadal function of patients with Turner syndrome (TS) is variable. Individuals with mosaicism characterized by 45,X/46,XX or 45,X/47,XXX are more likely to experience spontaneous menarche compared with other karyotypes. Prepubertal gonadotropins of TS patients with spontaneous menarche are reportedly normal or significantly lower than those of patients with induced menarche. The present study investigated an index of spontaneous and cyclical menstruation at 10-12 years old in TS. Subjects comprised 50 patients with TS, divided into three groups: Group A (n=7), with spontaneous menarche before 16 years old and regular menstruation for at least 1 year and 6 months; Group B (n=6), with irregular menstruation since menarche leading to secondary amenorrhea despite spontaneous menarche before 16 years old; and Group C (n=37), without spontaneous breast budding before 14 years old or without spontaneous menarche before 16 years old. Karyotype, LH and FSH concentrations at 10 and 12 years old were analyzed retrospectively. Spontaneous and cyclical menstruation was more frequently observed in TS with mosaicism characterized by 45,X/46,XX or 45,X/47,XXX than in TS with other karyotypes, as previously described. Spontaneous and cyclical menstruation in TS was observed when serum FSH level was <10 mIU/mL at 12 years old, suggesting this FSH level as an index of spontaneous and cyclical menstruation in TS.

[Study on the current status of spontaneous abortion of primigravid women in Jiaxing of Zhejiang province, China].

PubMed

Liang, Rui-ying; Ye, Rong-wei; Li, Hong-tian; Ren, Ai-guo; Liu, Jian-meng

2010-07-01

To study the current status of spontaneous abortion of primigravid women in Jiaxing areas of Zhejiang province of China. We analyzed the data from both perinatal healthcare surveillance program and spontaneous abortion, collected in Jiaxing areas by the Institute of Reproductive and Child Health, Peking University. The study population consisted of 14 769 primigravid women (excluding induced abortion, ectopic pregnancy and molar pregnancy as outcomes) attempting to become pregnant who registered between 1993 and 1995. 1454 spontaneous abortion cases were identified, with the spontaneous abortion rate as 9.8% (95%CI: 9.3% - 10.3%). The mean gestational weeks at pregnancy diagnosis were 7.6 ± 2.1 weeks, the mean gestational weeks at miscarriage were (10.1 ± 3.1) weeks and the incidence of first-trimester (≤ 12 weeks) spontaneous abortion was 7.3% (95%CI: 6.8% - 7.7%), accounting for 73.7% of all the spontaneous abortion cases. A peak for risk of miscarriage was around 8 - 13 weeks, accounting for 37.7% of all spontaneous abortion. The observed multiple Cox regression model showed that increased spontaneous abortion rates were observed in women with age at pregnancy ≥ 30, being peasants and with higher education level. The spontaneous abortion rate of primigravid women in Jiaxing areas was higher than in other areas of China. The maximum occurrence of spontaneous abortions was during period of 8-13 gestation weeks.

Paratrooper's Ankle Fracture: Posterior Malleolar Fracture

PubMed Central

Young, Ki Won; Cho, Jae Ho; Kim, Hyung Seuk; Cho, Hun Ki; Lee, Kyung Tai

2015-01-01

Background We assessed the frequency and types of ankle fractures that frequently occur during parachute landings of special operation unit personnel and analyzed the causes. Methods Fifty-six members of the special force brigade of the military who had sustained ankle fractures during parachute landings between January 2005 and April 2010 were retrospectively analyzed. The injury sites and fracture sites were identified and the fracture types were categorized by the Lauge-Hansen and Weber classifications. Follow-up surveys were performed with respect to the American Orthopedic Foot and Ankle Society ankle-hindfoot score, patient satisfaction, and return to preinjury activity. Results The patients were all males with a mean age of 23.6 years. There were 28 right and 28 left ankle fractures. Twenty-two patients had simple fractures and 34 patients had comminuted fractures. The average number of injury and fractures sites per person was 2.07 (116 injuries including a syndesmosis injury and a deltoid injury) and 1.75 (98 fracture sites), respectively. Twenty-three cases (41.07%) were accompanied by posterior malleolar fractures. Fifty-five patients underwent surgery; of these, 30 had plate internal fixations. Weber type A, B, and C fractures were found in 4, 38, and 14 cases, respectively. Based on the Lauge-Hansen classification, supination-external rotation injuries were found in 20 cases, supination-adduction injuries in 22 cases, pronation-external rotation injuries in 11 cases, tibiofibular fractures in 2 cases, and simple medial malleolar fractures in 2 cases. The mean follow-up period was 23.8 months, and the average follow-up American Orthopedic Foot and Ankle Society ankle-hindfoot score was 85.42. Forty-five patients (80.36%) reported excellent or good satisfaction with the outcome. Conclusions Posterior malleolar fractures occurred in 41.07% of ankle fractures sustained in parachute landings. Because most of the ankle fractures in parachute injuries were compound fractures, most cases had to undergo surgical repairs. PMID:25729514

Paratrooper's ankle fracture: posterior malleolar fracture.

PubMed

Young, Ki Won; Kim, Jin-su; Cho, Jae Ho; Kim, Hyung Seuk; Cho, Hun Ki; Lee, Kyung Tai

2015-03-01

We assessed the frequency and types of ankle fractures that frequently occur during parachute landings of special operation unit personnel and analyzed the causes. Fifty-six members of the special force brigade of the military who had sustained ankle fractures during parachute landings between January 2005 and April 2010 were retrospectively analyzed. The injury sites and fracture sites were identified and the fracture types were categorized by the Lauge-Hansen and Weber classifications. Follow-up surveys were performed with respect to the American Orthopedic Foot and Ankle Society ankle-hindfoot score, patient satisfaction, and return to preinjury activity. The patients were all males with a mean age of 23.6 years. There were 28 right and 28 left ankle fractures. Twenty-two patients had simple fractures and 34 patients had comminuted fractures. The average number of injury and fractures sites per person was 2.07 (116 injuries including a syndesmosis injury and a deltoid injury) and 1.75 (98 fracture sites), respectively. Twenty-three cases (41.07%) were accompanied by posterior malleolar fractures. Fifty-five patients underwent surgery; of these, 30 had plate internal fixations. Weber type A, B, and C fractures were found in 4, 38, and 14 cases, respectively. Based on the Lauge-Hansen classification, supination-external rotation injuries were found in 20 cases, supination-adduction injuries in 22 cases, pronation-external rotation injuries in 11 cases, tibiofibular fractures in 2 cases, and simple medial malleolar fractures in 2 cases. The mean follow-up period was 23.8 months, and the average follow-up American Orthopedic Foot and Ankle Society ankle-hindfoot score was 85.42. Forty-five patients (80.36%) reported excellent or good satisfaction with the outcome. Posterior malleolar fractures occurred in 41.07% of ankle fractures sustained in parachute landings. Because most of the ankle fractures in parachute injuries were compound fractures, most cases had to undergo surgical repairs.

Fracture predictive ability of physical performance tests and history of falls in elderly women: a 10-year prospective study.

PubMed

Wihlborg, A; Englund, M; Åkesson, K; Gerdhem, P

2015-08-01

In a large cohort of elderly women followed for 10 years, we found that balance, gait speed, and self-reported history of fall independently predicted fracture. These clinical risk factors are easily evaluated and therefore advantageous in a clinical setting. They would improve fracture risk assessment and thereby also fracture prevention. The aim of this study was to identify additional risk factors for osteoporosis-related fracture by investigating the fracture predictive ability of physical performance tests and self-reported history of falls. In the population-based Osteoporosis Prospective Risk Assessment study (OPRA), 1044 women were recruited at the age of 75 and followed for 10 years. At inclusion, knee extension force, standing balance, gait speed, and bone mineral density (BMD) were examined. Falls the year before investigation was assessed by questionnaire. Cox proportional hazards regression analysis was used to determine fracture hazard ratios (HR) with BMD, history of fracture, BMI, smoking habits, bisphosphonate, vitamin D, glucocorticoid, and alcohol use as covariates. Continuous variables were standardized and HR shown for each standard deviation change. Of all women, 427 (41%) sustained at least one fracture during the 10-year follow-up. Failing the balance test had an HR of 1.98 (1.18-3.32) for hip fracture. Each standard deviation decrease in gait speed was associated with an HR of 1.37 (1.14-1.64) for hip fracture. Previous fall had an HR of 1.30 (1.03-1.65) for any fracture; 1.39 (1.08-1.79) for any osteoporosis-related fracture; and 1.60 (1.03-2.48) for distal forearm fracture. Knee extension force did not show fracture predictability. The balance test, gait speed test, and self-reported history of fall all hold independent fracture predictability. Consideration of these clinical risk factors for fracture would improve the fracture risk assessment and subsequently also fracture prevention.

The use of hybrid fractures in paleostress determinations: test case with the the Palygorskite-bearing fractures in the Kinshasa area, DR Congo

NASA Astrophysics Data System (ADS)

Delvaux, Damien; Gloire, Ganza; Mees, Florias; Lahogue, Pascale

2014-05-01

Hybrid fractures represent the transition from extension fracture to shear fracture (Ramsey and Chester, 2004, Nature 428, 63-66). Although hybrid fractures have long been hypothesized to represent brittle fracture types between the extension and shear fractures end-members, it was only in 2004 that these authors succeeded to demonstrate their existence experimentally. As a consequence, observation of hybrid fractures in naturally deformed rocks remained ambiguous for a long time and only few studies reported their natural existence. Hybrid fractures have also not been considered so far as brittle element in paleostress reconstructions as their kinematic understanding was unclear. The Paleozoic Inkisi red sandstones of the West-Congo Supergroup in the region of Kinshasa and Brazzaville (Congo) are affected by prominent fracture sets, the most prominent of which are filled by palygorskite veins. They were formed in a strike-slip setting related to intraplate stress field generated by the mid Atlantic ridge push since that became efficient in late Cretaceous. We found an almost continuous range of fracture types, from plume joints to open fractures filled with calcite-palygorskite but without slip striae, and slickensided fractures with only thin films of redeposited palygorskite. The structural data have been analyzed with the Win-Tensor program (version 5.0.1) which has been adapted to consider hybrid fractures. Those are characterized by extension and shear, as opposed to tension fractures, on which no shear movement occurs, and to shear fractures, on which contraction occurs instead of extension. The results obtained suggest that the fractures have been initiated locally as plume joint and developed laterally under hybrid conditions. Later, some of them have been reactivated as strike-slip shear fractures and a new conjugated set appeared. Overall, this illustrates the progressive development with time of the stress state corresponding to an increase in the sigma 1 - sigma 3 stress difference.

External validation of the Garvan nomograms for predicting absolute fracture risk: the Tromsø study.

PubMed

Ahmed, Luai A; Nguyen, Nguyen D; Bjørnerem, Åshild; Joakimsen, Ragnar M; Jørgensen, Lone; Størmer, Jan; Bliuc, Dana; Center, Jacqueline R; Eisman, John A; Nguyen, Tuan V; Emaus, Nina

2014-01-01

Absolute risk estimation is a preferred approach for assessing fracture risk and treatment decision making. This study aimed to evaluate and validate the predictive performance of the Garvan Fracture Risk Calculator in a Norwegian cohort. The analysis included 1637 women and 1355 aged 60+ years from the Tromsø study. All incident fragility fractures between 2001 and 2009 were registered. The predicted probabilities of non-vertebral osteoporotic and hip fractures were determined using models with and without BMD. The discrimination and calibration of the models were assessed. Reclassification analysis was used to compare the models performance. The incidence of osteoporotic and hip fracture was 31.5 and 8.6 per 1000 population in women, respectively; in men the corresponding incidence was 12.2 and 5.1. The predicted 5-year and 10-year probability of fractures was consistently higher in the fracture group than the non-fracture group for all models. The 10-year predicted probabilities of hip fracture in those with fracture was 2.8 (women) to 3.1 times (men) higher than those without fracture. There was a close agreement between predicted and observed risk in both sexes and up to the fifth quintile. Among those in the highest quintile of risk, the models over-estimated the risk of fracture. Models with BMD performed better than models with body weight in correct classification of risk in individuals with and without fracture. The overall net decrease in reclassification of the model with weight compared to the model with BMD was 10.6% (p = 0.008) in women and 17.2% (p = 0.001) in men for osteoporotic fractures, and 13.3% (p = 0.07) in women and 17.5% (p = 0.09) in men for hip fracture. The Garvan Fracture Risk Calculator is valid and clinically useful in identifying individuals at high risk of fracture. The models with BMD performed better than those with body weight in fracture risk prediction.

Growth Kinematics of Opening-Mode Fractures

NASA Astrophysics Data System (ADS)

Eichhubl, P.; Alzayer, Y.; Laubach, S.; Fall, A.

2014-12-01

Fracture aperture is a primary control on flow in fractured reservoirs of low matrix permeability including unconventional oil and gas reservoirs and most geothermal systems. Guided by principles of linear elastic fracture mechanics, fracture aperture is generally assumed to be a linear function of fracture length and elastic material properties. Natural opening-mode fractures with significant preserved aperture are observed in core and outcrop indicative of fracture opening strain accommodated by permanent solution-precipitation creep. Fracture opening may thus be decoupled from length growth if the material effectively weakens after initial elastic fracture growth by either non-elastic deformation processes or changes in elastic properties. To investigate the kinematics of fracture length and aperture growth, we reconstructed the opening history of three opening-mode fractures that are bridged by crack-seal quartz cement in Travis Peak Sandstone of the SFOT-1 well, East Texas. Similar crack-seal cement bridges had been interpreted to form by repeated incremental fracture opening and subsequent precipitation of quartz cement. We imaged crack-seal cement textures for bridges sampled at varying distance from the tips using scanning electron microscope cathodoluminescence, and determined the number and thickness of crack-seal cement increments as a function of position along the fracture length and height. Observed trends in increment number and thickness are consistent with an initial stage of fast fracture propagation relative to aperture growth, followed by a stage of slow propagation and pronounced aperture growth. Consistent with fluid inclusion observations indicative of fracture opening and propagation occurring over 30-40 m.y., we interpret the second phase of pronounced aperture growth to result from fracture opening strain accommodated by solution-precipitation creep and concurrent slow, possibly subcritical, fracture propagation. Similar deformation mechanisms are envisioned to govern fracture growth over shorter timescales in reactive chemical subsurface environments including CO2 reservoirs, organic-rich shales, and geothermal systems.

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.

Prevalence of carpal fracture in Singapore.

PubMed

Hey, Hwee Weng Dennis; Dennis, Hey Hwee Weng; Chong, Alphonsus Khin Sze; Sze, Alphonsus Chong Khin; Murphy, Diarmuid

2011-02-01

To determine the prevalence of carpal fracture in Singapore, to compare demographic differences between isolated scaphoid and other carpal fractures, and to identify parameters associated with multiple carpal fractures. A total of 149 patients with 162 carpal fractures seen at the National University Hospital in 2009 were enrolled into the study. We retrospectively reviewed their case records and radiographic studies. Pertinent demographic data including patient age, gender, occupation, injured wrist, dominant hand, mechanism of injury, and type of carpal fracture were then recorded and statistically analyzed. We also performed a separate analysis of isolated scaphoid versus other carpal fractures and single versus multiple carpal fractures. Patients with carpal fracture were predominantly male (132), below 40 years of age (116), and usually right hand dominant (136). The more common occupations were students (30), full-time military national servicemen (24), and construction workers (14). Most presented after a fall on an outstretched hand from standing height (81). The scaphoid was the most common single carpal fracture (99). This was followed by triquetrum (27), hamate (5), pisiform (4), lunate (2), capitate (1), and trapezium (1). No fracture of the trapezoid was encountered. Ten patients had multiple carpal fractures, of which 4 were perilunate fracture dislocations. The mean age and male/female ratio for isolated scaphoid and other carpal fractures was 26 years versus 41 years (p<.001) and 13:1 versus 4:1 (p=.036), respectively. A high-energy mechanism of injury was the only parameter associated with multiple carpal fractures (p=.009). The prevalence of carpal fracture in our population was consistent with studies performed in other countries. Military conscription was identified as an at-risk activity predisposing to carpal fracture. Isolated scaphoid and other carpal fractures exhibit different demographics in terms of age and gender, which may be related to differences in the mechanism of injury. A high-energy mechanism of injury was associated with multiple carpal fractures. Copyright © 2011 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Epidemiology and recent trends of geriatric fractures presenting to the emergency department for United States population from year 2004-2014.

PubMed

Baidwan, N K; Naranje, S M

2017-01-01

Fractures in geriatric age group (over 65 years of age) are an important public health issue and frequent causes of emergency room visits. The purpose of this descriptive epidemiological study was to present the epidemiology of geriatric fractures and their trends in the USA using National Electronic Injury Surveillance System (NEISS) database from year 2004-2014. National Electronic Injury Surveillance System (NEISS) Database was queried for all fracture injuries from 2004 to 2014 for ages 65 years and above. The proportions of fractures based on NEISS national estimates were calculated and their trends using linear regression over last 11 years were studied. Lower trunk (pelvis, hip and lower spine) fractures were the most common (34% for year 2014) type of fractures in this age group. Upper trunk (upper spine, clavicle and ribs) fractures were the second most common type of fractures (13% for year 2014). Other body parts commonly fractured involved the upper arm and wrist with an average of 7% fractures in both during the study period. About 5% of geriatric fractures pertained to shoulder and upper leg. Although less common, there was also about 2% increase in fractures to face and neck in 2014 as compared to about 3.2% and 1% respectively in 2004. Fractures to other body parts were less common with no major variations during the study period. Overall, lower trunk (hip, pelvic and lower spine) fractures were the most common geriatric fractures followed by upper trunk (upper spine, clavicle and rib) fractures. We suggest that there were decreasing trends for incidence of lower trunk, wrist and upper body fractures over the last 11 years (2004-2014). Approximately half of the geriatric fractures presenting to Emergency Department needed hospitalizations. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Clinical effects of internal fixation for ulnar styloid fractures associated with distal radius fractures: A matched case-control study.

PubMed

Sawada, Hideyoshi; Shinohara, Takaaki; Natsume, Tadahiro; Hirata, Hitoshi

2016-11-01

Ulnar styloid fractures are often associated with distal radius fractures. However, controversy exists regarding whether to treat ulnar styloid fractures. This study aimed to evaluate clinical effects of internal fixation for ulnar styloid fractures after distal radius fractures were treated with the volar locking plate system. We used prospectively collected data of distal radius fractures. 111 patients were enrolled in this study. A matched case-control study design was used. We selected patients who underwent fixation for ulnar styloid fractures (case group). Three control patients for each patient of the case group were matched on the basis of age, sex, and fracture type of distal radius fractures from among patients who did not undergo fixation for ulnar styloid fractures (control group). The case group included 16 patients (7 men, 9 women; mean age: 52.6 years; classification of ulnar styloid fractures: center, 3; base, 11; and proximal, 2). The control group included 48 patients (15 men, 33 women; mean age: 61.1 years; classification of ulnar styloid fractures: center, 10; base, 31; and proximal, 7). For radiographic examination, the volar tilt angle, radial inclination angle, and ulnar variance length were measured, and the union of ulnar styloid fractures was judged. For clinical examination, the range of motions, grip strength, Hand20 score, and Numeric Rating Scale score were evaluated. There was little correction loss for each radiological parameter of fracture reduction, and these parameters were not significantly different between the groups. The bone-healing rate of ulnar styloid fractures was significantly higher in the case group than in the control group, but the clinical results were not significantly different. We revealed that there was no need to fix ulnar styloid fractures when distal radius fractures were treated via open reduction and internal fixation with a volar locking plate system. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Linear Elastic and Cohesive Fracture Analysis to Model Hydraulic Fracture in Brittle and Ductile Rocks

NASA Astrophysics Data System (ADS)

Yao, Yao

2012-05-01

Hydraulic fracturing technology is being widely used within the oil and gas industry for both waste injection and unconventional gas production wells. It is essential to predict the behavior of hydraulic fractures accurately based on understanding the fundamental mechanism(s). The prevailing approach for hydraulic fracture modeling continues to rely on computational methods based on Linear Elastic Fracture Mechanics (LEFM). Generally, these methods give reasonable predictions for hard rock hydraulic fracture processes, but still have inherent limitations, especially when fluid injection is performed in soft rock/sand or other non-conventional formations. These methods typically give very conservative predictions on fracture geometry and inaccurate estimation of required fracture pressure. One of the reasons the LEFM-based methods fail to give accurate predictions for these materials is that the fracture process zone ahead of the crack tip and softening effect should not be neglected in ductile rock fracture analysis. A 3D pore pressure cohesive zone model has been developed and applied to predict hydraulic fracturing under fluid injection. The cohesive zone method is a numerical tool developed to model crack initiation and growth in quasi-brittle materials considering the material softening effect. The pore pressure cohesive zone model has been applied to investigate the hydraulic fracture with different rock properties. The hydraulic fracture predictions of a three-layer water injection case have been compared using the pore pressure cohesive zone model with revised parameters, LEFM-based pseudo 3D model, a Perkins-Kern-Nordgren (PKN) model, and an analytical solution. Based on the size of the fracture process zone and its effect on crack extension in ductile rock, the fundamental mechanical difference of LEFM and cohesive fracture mechanics-based methods is discussed. An effective fracture toughness method has been proposed to consider the fracture process zone effect on the ductile rock fracture.

The ameloblastin extracellular matrix molecule enhances bone fracture resistance and promotes rapid bone fracture healing.

PubMed

Lu, Xuanyu; Li, Wenjin; Fukumoto, Satoshi; Yamada, Yoshihiko; Evans, Carla A; Diekwisch, Tom; Luan, Xianghong

2016-01-01

The extracellular matrix (ECM) provides structural support, cell migration anchorage, cell differentiation cues, and fine-tuned cell proliferation signals during all stages of bone fracture healing, including cartilaginous callus formation, callus remodeling, and bony bridging of the fracture gap. In the present study we have defined the role of the extracellular matrix protein ameloblastin (AMBN) in fracture resistance and fracture healing of mouse long bones. To this end, long bones from WT and AMBN(Δ5-6) truncation model mice were subjected to biomechanical analysis, fracture healing assays, and stem cell colony formation comparisons. The effect of exogenous AMBN addition to fracture sites was also determined. Our data indicate that lack of a functional AMBN in the bone matrix resulted in 31% decreased femur bone mass and 40% reduced energy to failure. On a cellular level, AMBN function inhibition diminished the proliferative capacity of fracture repair callus cells, as evidenced by a 58% reduction in PCNA and a 40% reduction in Cyclin D1 gene expression, as well as PCNA immunohistochemistry. In terms of fracture healing, AMBN truncation was associated with an enhanced and prolonged chondrogenic phase, resulting in delayed mineralized tissue gene expression and delayed ossification of the fracture repair callus. Underscoring a role of AMBN in fracture healing, there was a 6.9-fold increase in AMBN expression at the fracture site one week after fracture, and distinct AMBN immunolabeling in the fracture gap. Finally, application of exogenous AMBN protein to bone fracture sites accelerated callus formation and bone fracture healing (33% increase in bone volume and 19% increase in bone mineral density), validating the findings of our AMBN loss of function studies. Together, these data demonstrate the functional importance of the AMBN extracellular matrix protein in bone fracture prevention and rapid fracture healing. Copyright © 2016 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

The Ameloblastin extracellular matrix molecule enhances bone fracture resistance and promotes rapid bone fracture healing

PubMed Central

Lu, Xuanyu; Li, Wenjin; Fukumoto, Satoshi; Yamada, Yoshihiko; Evans, Carla; Diekwisch, Thomas G.H.; Luan, Xianghong

2016-01-01

The extracellular matrix (ECM) provides structural support, cell migration anchorage, cell differentiation cues, and fine-tuned cell proliferation signals during all stages of bone fracture healing, including cartilaginous callus formation, callus remodeling, and bony bridging of the fracture gap. In the present study we have defined the role of the extracellular matrix protein ameloblastin (AMBN) in fracture resistance and fracture healing of mouse long bones. To this end, long bones from WT and AMBNΔ5-6 truncation model mice were subjected to biomechanical analysis, fracture healing assays, and stem cell colony formation comparisons. The effect of exogenous AMBN addition to fracture sites was also determined. Our data indicate that lack of a functional AMBN in the bone matrix resulted in 31% decreased femur bone mass and 40% reduced energy to failure. On a cellular level, AMBN function inhibition diminished the proliferative capacity of fracture repair callus cells, as evidenced by a 58% reduction in PCNA and a 40% reduction in Cyclin D1 gene expression, as well as PCNA immunohistochemistry. In terms of fracture healing, AMBN truncation was associated with an enhanced and prolonged chondrogenic phase, resulting in delayed mineralized tissue gene expression and delayed ossification of the fracture repair callus. Underscoring a role of AMBN in fracture healing, there was a 6.9-fold increase in AMBN expression at the fracture site one week after fracture, and distinct AMBN immunolabeling in the fracture gap. Finally, application of exogenous AMBN protein to bone fracture sites accelerated callus formation and bone fracture healing (33% increase in bone volume and 19% increase in bone mineral density), validating the findings of our AMBN loss of function studies. Together, these data demonstrate the functional importance of the AMBN extracellular matrix protein in bone fracture prevention and rapid fracture healing. PMID:26899203

Burden of non-hip, non-vertebral fractures on quality of life in postmenopausal women: the Global Longitudinal study of Osteoporosis in Women (GLOW).

PubMed

Roux, C; Wyman, A; Hooven, F H; Gehlbach, S H; Adachi, J D; Chapurlat, R D; Compston, J E; Cooper, C; Díez-Pérez, A; Greenspan, S L; Lacroix, A Z; Netelenbos, J C; Pfeilschifter, J; Rossini, M; Saag, K G; Sambrook, P N; Silverman, S; Siris, E S; Watts, N B; Boonen, S

2012-12-01

Among 50,461 postmenopausal women, 1,822 fractures occurred (57% minor non-hip, non-vertebral [NHNV], 26% major NHNV, 10% spine, 7% hip) over 1 year. Spine fractures had the greatest detrimental effect on EQ-5D, followed by major NHNV and hip fractures. Decreases in physical function and health status were greatest for spine or hip fractures. There is growing evidence that NHNV fractures result in substantial morbidity and healthcare costs. The aim of this prospective study was to assess the effect of these NHNV fractures on quality of life. We analyzed the 1-year incidences of hip, spine, major NHNV (pelvis/leg, shoulder/arm) and minor NHNV (wrist/hand, ankle/foot, rib/clavicle) fractures among women from the Global Longitudinal study of Osteoporosis in Women (GLOW). Health-related quality of life (HRQL) was analyzed using the EuroQol EQ-5D tool and the SF-36 health survey. Among 50,461 women analyzed, there were 1,822 fractures (57% minor NHNV, 26% major NHNV, 10% spine, 7% hip) over 1 year. Spine fractures had the greatest detrimental effect on EQ-5D summary scores, followed by major NHNV and hip fractures. The number of women with mobility problems increased most for those with major NHNV and spine fractures (both +8%); spine fractures were associated with the largest increases in problems with self care (+11%), activities (+14%), and pain/discomfort (+12%). Decreases in physical function and health status were greatest for those with spine or hip fractures. Multivariable modeling found that EQ-5D reduction was greatest for spine fractures, followed by hip and major/minor NHNV. Statistically significant reductions in SF-36 physical function were found for spine fractures, and were borderline significant for major NHNV fractures. This prospective study shows that NHNV fractures have a detrimental effect on HRQL. Efforts to optimize the care of osteoporosis patients should include the prevention of NHNV fractures.

Forecasting the burden of future postmenopausal hip fractures.

PubMed

Omsland, T K; Magnus, J H

2014-10-01

A growing elderly population is expected worldwide, and the rate of hip fractures is decisive for the future fracture burden. Significant declines in hip fracture rates in Norway, the USA, France, Germany, and the UK are required to counteract the impact of the ageing effects. This study aims to evaluate the consequences of the expected growth of the elderly population worldwide on the hip fracture burden using Norway as an example. Furthermore, we wanted to estimate the decline in hip fracture rates required to counteract the anticipated increase in the burden of hip fracture for Norway, the USA, France, Germany, and the UK. The burden of future postmenopausal hip fractures in Norway were estimated given (1) constant age-specific rates, (2) continued decline, and (3) different cohort scenarios. Based on population projection estimates and population age-specific hip fracture rates in women 65 years and older, we calculated the required declines in hip fracture rates needed to counteract the growing elderly populations in Norway, the USA, France, Germany, and the UK. The level of age-specific hip fracture rates had a huge impact on the future hip fracture burden in Norway. Even if the hip fracture rates decline at the same speed, a 22 % increase in the burden of hip fractures can be expected by 2040. An annual decline in hip fracture rates of 1.1-2.2 % until 2040 is required to counteract the effects of the growing elderly population on the future burden of hip fractures in Norway, the USA, France, Germany, and the UK. Hip fracture rates have a great impact on the burden of hip fractures. The rates will have to decline significantly to counteract the impact of a growing elderly population. A change in preventive strategies and further studies are warranted to identify the complex causes associated to hip fractures.

Fractures of the manubrium sterni: treatment options and a possible classification of different types of fractures

PubMed Central

Krinner, Sebastian; Oppel, Pascal; Grupp, Sina; Schulz-Drost, Melanie; Hennig, Friedrich F.; Langenbach, Andreas

2018-01-01

Background Sternum fractures are mostly located on the sternal corpus, seldom on the manubrium. Fractures of the sternal manubrium are, however, more frequently associated with severe concomitant injuries of thoracic organs, and therefore deserve special attention. In addition, in its function as a capstone in between the anterior chest wall and the shoulder girdle, it is exposed to a multiplicity of forces. Therefore the questions arise what types of fractures are observed in today’s clinical practice, how to classify them and which treatment options are available. This study reports on different types of fractures which involve the manubrium sterni. Methods Between January 2012 and October 2014, data was collected from all severely injured patients (ISS ≥16), which received a CT scan of the thorax in our Level-I-Trauma Center and retrospectively analyzed concerning sternal fractures. Fracture type, collateral injuries, age, and information about the circumstances of the accident were noted. Results Of 890 evaluable patients, 154 (17.3%) had a fracture of the sternum and 23 (2.6%) of the manubrium. Fractures of the manubrium appeared in following types: A-type—transverse fracture (n=11) in 1st intercostal space by direct blunt trauma or flexion of the torso with sagittal instability; B-type—oblique fracture (n=9) by seat belt injury with rotatory instability; C-type—combined, more fragmentary fracture (n=3) by direct blunt trauma with simultaneous flexion of the torso and multi directional instability. Fractures only little dislocation were treated conservatively, and unstable fractures were surgically stabilized (n=10). Conclusions In summary, three main types of fractures could be found. A-type fractures were stabilized with a longitudinal plate osteosynthesis and B-type fractures with transverse positioned plates. To treat complex C-type fractures, plates with a T- or H-form could be a good solution. Level of evidence: Level III retrospective prognostic cohort study PMID:29707289

Fracture of Fully-coated Femoral Stem after Primary Total Hip Arthroplasty for Nonunion of Intertrochanteric Fracture: A Case Report.

PubMed

Chun, Young Soo; Juh, Hyung Suk; Cho, Yoon Je; Rhyu, Kee Hyung

2015-09-01

Femoral stem fracture is an uncommon reason for the failure of total hip arthroplasty, with only 16 cases of fully coated stem fractures reported to date. Here we report a case in which a fully coated primary femoral stem fracture occurred after conversion to total hip arthroplasty for the non-union of an intertrochanteric fracture of the femur. Metallurgic evaluation of the etiology and mechanism revealed that the fracture was initiated by fatigue-related failure and completed by ductile failure on the posterior side of the fracture. Considering the recent trend of treating an intertrochanteric fracture with hip arthroplasty, possible stem failure should be considered, since most patients will have at least one of the known risk factors for stem fracture.

Fracture of Fully-coated Femoral Stem after Primary Total Hip Arthroplasty for Nonunion of Intertrochanteric Fracture: A Case Report

PubMed Central

Chun, Young Soo; Juh, Hyung Suk; Cho, Yoon Je

2015-01-01

Femoral stem fracture is an uncommon reason for the failure of total hip arthroplasty, with only 16 cases of fully coated stem fractures reported to date. Here we report a case in which a fully coated primary femoral stem fracture occurred after conversion to total hip arthroplasty for the non-union of an intertrochanteric fracture of the femur. Metallurgic evaluation of the etiology and mechanism revealed that the fracture was initiated by fatigue-related failure and completed by ductile failure on the posterior side of the fracture. Considering the recent trend of treating an intertrochanteric fracture with hip arthroplasty, possible stem failure should be considered, since most patients will have at least one of the known risk factors for stem fracture. PMID:27536622

Trends in the volume of operative treatment of midshaft clavicle fractures in children and adolescents: a retrospective, 12-year, single-institution analysis.

PubMed

Suppan, Catherine A; Bae, Donald S; Donohue, Kyna S; Miller, Patricia E; Kocher, Mininder S; Heyworth, Benton E

2016-07-01

The purpose of this study was to examine institutional trends in the volume of clavicle fractures in children and adolescents. Medical records were retrospectively reviewed to identify patients aged 10-18 years treated for a clavicle fracture between 1999 and 2011 at a single tertiary-care pediatric hospital. There were significant increases in the number of clavicle fractures seen annually, of midshaft clavicle fractures, and of midshaft clavicle fractures treated operatively. The percentage of midshaft clavicle fractures treated with fixation also increased significantly. The volumes of clavicle fractures and midshaft clavicle fractures treated operatively appear to be increasing. Despite a lack of evidence-based support, the frequency of fixation of midshaft clavicle fractures appear to be increasing in the pediatric population.

Complementary hydro-mechanical coupled finite/discrete element and microseismic modelling to predict hydraulic fracture propagation in tight shale reservoirs

NASA Astrophysics Data System (ADS)

Profit, Matthew; Dutko, Martin; Yu, Jianguo; Cole, Sarah; Angus, Doug; Baird, Alan

2016-04-01

This paper presents a novel approach to predict the propagation of hydraulic fractures in tight shale reservoirs. Many hydraulic fracture modelling schemes assume that the fracture direction is pre-seeded in the problem domain discretisation. This is a severe limitation as the reservoir often contains large numbers of pre-existing fractures that strongly influence the direction of the propagating fracture. To circumvent these shortcomings, a new fracture modelling treatment is proposed where the introduction of discrete fracture surfaces is based on new and dynamically updated geometrical entities rather than the topology of the underlying spatial discretisation. Hydraulic fracturing is an inherently coupled engineering problem with interactions between fluid flow and fracturing when the stress state of the reservoir rock attains a failure criterion. This work follows a staggered hydro-mechanical coupled finite/discrete element approach to capture the key interplay between fluid pressure and fracture growth. In field practice, the fracture growth is hidden from the design engineer and microseismicity is often used to infer hydraulic fracture lengths and directions. Microseismic output can also be computed from changes of the effective stress in the geomechanical model and compared against field microseismicity. A number of hydraulic fracture numerical examples are presented to illustrate the new technology.

Corrective Septorhinoplasty in Acute Nasal Bone Fractures.

PubMed

Kim, Jisung; Jung, Hahn Jin; Shim, Woo Sub

2018-03-01

Closed reduction is generally recommended for acute nasal bone fractures, and rhinoplasty is considered in cases with an unsatisfactory outcome. However, concomitant rhinoplasty with fracture reduction might achieve better surgical outcomes. This study investigated the surgical techniques and outcomes in patients who underwent rhinoplasty and fracture reduction concomitantly, during the acute stage of nasal bone fracture. Forty-five patients who underwent concomitant rhinoplasty and fracture reduction were enrolled. Nasal bone fractures were classified into three major types (type I, simple fracture; type II, fracture line that mimics nasal osteotomy; and type III, comminuted fracture) based on computed tomography images and preoperative facial images. Two independent otolaryngology-head and neck surgeons evaluated the surgical outcomes and telephone based survey were made to evaluate patients satisfaction. Among 45 patients, there were 39 males and 6 females. Type I was the commonest type of fracture with 18 patients (40%), while the most frequently used surgical technique for corrective surgery was dorsal augmentation with 44 patients (97.8%). The mean visual analogue scale satisfaction score of the surgeons and patients were 7.62 and 8, respectively, with no significant differences between fracture types. Concomitant rhinoplasty with fracture reduction can be performed for acute nasal bone fracture patients, and it might lead to better aesthetic outcomes.

Thermal convection in three-dimensional fractured porous media

NASA Astrophysics Data System (ADS)

Mezon, C.; Mourzenko, V. V.; Thovert, J.-F.; Antoine, R.; Fontaine, F.; Finizola, A.; Adler, P. M.

2018-01-01

Thermal convection is numerically computed in three-dimensional (3D) fluid saturated isotropically fractured porous media. Fractures are randomly inserted as two-dimensional (2D) convex polygons. Flow is governed by Darcy's 2D and 3D laws in the fractures and in the porous medium, respectively; exchanges take place between these two structures. Results for unfractured porous media are in agreement with known theoretical predictions. The influence of parameters such as the fracture aperture (or fracture transmissivity) and the fracture density on the heat released by the whole system is studied for Rayleigh numbers up to 150 in cubic boxes with closed-top conditions. Then, fractured media are compared to homogeneous porous media with the same macroscopic properties. Three major results could be derived from this study. The behavior of the system, in terms of heat release, is determined as a function of fracture density and fracture transmissivity. First, the increase in the output flux with fracture density is linear over the range of fracture density tested. Second, the increase in output flux as a function of fracture transmissivity shows the importance of percolation. Third, results show that the effective approach is not always valid, and that the mismatch between the full calculations and the effective medium approach depends on the fracture density in a crucial way.

Influence of Fracture Width on Sealability in High-Strength and Ultra-Low-Permeability Concrete in Seawater.

PubMed

Fukuda, Daisuke; Nara, Yoshitaka; Hayashi, Daisuke; Ogawa, Hideo; Kaneko, Katsuhiko

2013-06-25

For cementitious composites and materials, the sealing of fractures can occur in water by the precipitation of calcium compounds. In this study, the sealing behavior in a macro-fractured high-strength and ultra-low-permeability concrete (HSULPC) specimen was investigated in simulated seawater using micro-focus X-ray computed tomography (CT). In particular, the influence of fracture width (0.10 and 0.25 mm) on fracture sealing was investigated. Precipitation occurred mainly at the outermost parts of the fractured surface of the specimen for both fracture widths. While significant sealing was observed for the fracture width of 0.10 mm, sealing was not attained for the fracture width of 0.25 mm within the observation period (49 days). Examination of the sealed regions on the macro-fracture was performed using a three-dimensional image registration technique and applying image subtraction between the CT images of the HSULPC specimen before and after maintaining the specimen in simulated seawater. The temporal change of the sealing deposits for the fracture width of 0.10 mm was much larger than that for the fracture width of 0.25 mm. Therefore, it is concluded that the sealability of the fracture in the HSULPC is affected by the fracture width.

Laboratory testing on infiltration in single synthetic fractures

NASA Astrophysics Data System (ADS)

Cherubini, Claudia; Pastore, Nicola; Li, Jiawei; Giasi, Concetta I.; Li, Ling

2017-04-01

An understanding of infiltration phenomena in unsaturated rock fractures is extremely important in many branches of engineering for numerous reasons. Sectors such as the oil, gas and water industries are regularly interacting with water seepage through rock fractures, yet the understanding of the mechanics and behaviour associated with this sort of flow is still incomplete. An apparatus has been set up to test infiltration in single synthetic fractures in both dry and wet conditions. To simulate the two fracture planes, concrete fractures have been moulded from 3D printed fractures with varying geometrical configurations, in order to analyse the influence of aperture and roughness on infiltration. Water flows through the single fractures by means of a hydraulic system composed by an upstream and a downstream reservoir, the latter being subdivided into five equal sections in order to measure the flow rate in each part to detect zones of preferential flow. The fractures have been set at various angles of inclination to investigate the effect of this parameter on infiltration dynamics. The results obtained identified that altering certain fracture parameters and conditions produces relevant effects on the infiltration process through the fractures. The main variables influencing the formation of preferential flow are: the inclination angle of the fracture, the saturation level of the fracture and the mismatch wavelength of the fracture.

The influence of renal dialysis and hip fracture sites on the 10-year mortality of elderly hip fracture patients

PubMed Central

Hung, Li-Wei; Hwang, Yi-Ting; Huang, Guey-Shiun; Liang, Cheng-Chih; Lin, Jinn

2017-01-01

Abstract Hip fractures in older people requiring dialysis are associated with high mortality. Our study primarily aimed to evaluate the specific burden of dialysis on the mortality rate following hip fracture. The secondary aim was to clarify the effect of the fracture site on mortality. A retrospective cohort study was conducted using Taiwan's National Health Insurance Research Database to analyze nationwide health data regarding dialysis and non-dialysis patients ≥65 years who sustained a first fragility-related hip fracture during the period from 2001 to 2005. Each dialysis hip fracture patient was age- and sex-matched to 5 non-dialysis hip fracture patients to construct the matched cohort. Survival status of patients was followed-up until death or the end of 2011. Survival analyses using multivariate Cox proportional hazards models and the Kaplan-Meier estimator were performed to compare between-group survival and impact of hip fracture sites on mortality. A total of 61,346 hip fracture patients were included nationwide. Among them, 997 dialysis hip fracture patients were identified and matched to 4985 non-dialysis hip fracture patients. Mortality events were 155, 188, 464, and 103 in the dialysis group, and 314, 382, 1505, and 284 in the non-dialysis group, with adjusted hazard ratios (associated 95% confidence intervals) of 2.58 (2.13–3.13), 2.95 (2.48–3.51), 2.84 (2.55–3.15), and 2.39 (1.94–2.93) at 0 to 3 months, 3 months to 1 year, 1 to 6 years, and 6 to 10 years after the fracture, respectively. In the non-dialysis group, survival was consistently better for patients who sustained femoral neck fractures compared to trochanteric fractures (0–10 years’ log-rank test, P < .001). In the dialysis group, survival of patients with femoral neck fractures was better than that of patients with trochanteric fractures only within the first 6 years post-fracture (0–6 years’ log-rank, P < .001). Dialysis was a significant risk factor of mortality in geriatric hip fracture patients. Survival outcome was better for non-dialysis patients with femoral neck fractures compared to those with trochanteric fractures throughout 10 years. However, the survival advantage of femoral neck fractures was limited to the first 6 years postinjury among dialysis patients. PMID:28906354

Morphology of the posteromedial fragment in pertrochanteric fractures: A three-dimensional computed tomography analysis.

PubMed

Sharma, Gaurav; Gn, Kiran Kumar; Khatri, Kavin; Singh, Ravijot; Gamanagatti, Shivanand; Sharma, Vijay

2017-02-01

In this study we describe the morphology of the posteromedial fragment in pertrochanteric fractures using 3D CT scans and answer two questions 1) Do differences exist between the 3D CT appearances of posteromedial fragments and the depictions made in the AO classification 2) Does the posteromedial fragment affect stability in pertrochanteric fractures, in terms of fracture collapse? Preoperative CT scans of eight 31-A1 and fifty 31-A2 fractures were analysed. The presence of PM fragment, its fragmentation, greater trochanter (GT) involvement, lesser trochanter (LT) fragment size (in terms of its posterior and medial extent as well as LT length), LT fragment displacement (in terms of medial displacement and rotation) were determined. All fractures were treated with a DHS. Fracture collapse was determined on postoperative radiographs. The relationship between fracture collapse and patient factors including age, gender, fracture type (A1 versus A2), characteristics of the posteromedial fragment, and the presence of a lateral wall fracture were determined. Three out of eight 31-A1 fractures demonstrated a separate GT fragment (three part fracture). Out of the 50 31-A2 fractures, 12 had a single PM fragment, which included the LT and GT in continuity. The more common four part fractures seem to form by further fragmentation of this basic form. In A2 fractures, the GT was almost always broken and the broken fragment comprised a mean 56% of normal GT. The LT fragment involved an average of 74% of the posterior wall, and an average of 36% of the medial wall of the proximal femur. Larger LT fragments were less displaced as compared to smaller fragments. Univariate regression analyses revealed that fracture collapse was significantly correlated with fracture type (A1 versus A2, p 0.036), GT size (p 0.002) and the presence of a lateral wall fracture (p<0.001). This study revealed some important differences between the 3D CT appearances and AO classification of pertrochanteric fractures. Further, neither fragmentation of the posteromedial fragment, nor the size of the lesser trochanter fragment was found to predict stability in pertrochanteric fractures. A perioperative lateral wall fracture is the main determinant of stability in these fractures. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nanophotonic Devices; Spontaneous Emission Faster than Stimulated Emission

DTIC Science & Technology

2016-02-02

optically pumped spontaneous emission, and electrically pumped spontaneous emission. We have observed a speedup of >300x, and we project a speedup of 2500x...The project has succeeded, both for optically pumped spontaneous emission, and electrically pumped spontaneous emission. We have observed a speedup...Fabricated Plasmonic Optical Transformer”, (with H. Choo, S. Cabrini, P.J. Schuck, X. Liang,) U.S. Patent No. 9,052,450 (Jun. 9, 2015). 2. “ Probes

Early Weightbearing After Operatively Treated Ankle Fractures: A Biomechanical Analysis.

PubMed

Tan, Eric W; Sirisreetreerux, Norachart; Paez, Adrian G; Parks, Brent G; Schon, Lew C; Hasenboehler, Erik A

2016-06-01

No consensus exists regarding the timing of weightbearing after surgical fixation of unstable traumatic ankle fractures. We evaluated fracture displacement and timing of displacement with simulated early weightbearing in a cadaveric model. Twenty-four fresh-frozen lower extremities were assigned to Group 1, bimalleolar ankle fracture (n=6); Group 2, trimalleolar ankle fracture with unfixed small posterior malleolar fracture (n=9); or Group 3, trimalleolar ankle fracture with fixed large posterior malleolar fracture (n=9) and tested with axial compressive load at 3 Hz from 0 to 1000 N for 250 000 cycles to simulate 5 weeks of full weightbearing. Displacement was measured by differential variable reluctance transducer. The average motion at all fracture sites in all groups was significantly less than 1 mm (P < .05). Group 1 displacement of the lateral and medial malleolus fracture was 0.1±0.1 mm and 0.4±0.4 mm, respectively. Group 2 displacement of the lateral, medial, and posterior malleolar fracture was 0.6±0.4 mm, 0.5±0.4 mm, and 0.5±0.6 mm, respectively. Group 3 displacement of the lateral, medial, and posterior malleolar fracture was 0.1±0.1 mm, 0.5±0.7 mm, and 0.5±0.4 mm, respectively. The majority of displacement (64.0% to 92.3%) occurred in the first 50 000 cycles. There was no correlation between fracture displacement and bone mineral density. No significant fracture displacement, no hardware failure, and no new fractures occurred in a cadaveric model of early weightbearing in unstable ankle fracture after open reduction and internal fixation. This study supports further investigation of early weightbearing postoperative protocols after fixation of unstable ankle fractures. © The Author(s) 2016.

Trajectory of social isolation following hip fracture: an analysis of the English Longitudinal Study of Ageing (ELSA) cohort.

PubMed

Smith, Toby O; Dainty, Jack R; MacGregor, Alex

2018-01-01

social isolation is defined as a lack of meaningful and sustained communication or interactions with social networks. There is limited understanding on the prevalence of social isolation and loneliness in people following hip fracture and no previous understanding of how this changes over time. to determine the prevalence and trajectory of social isolation and loneliness before a hip fracture, during the recovery phase and a minimum of 2 years post-hip fracture in an English population. data were from the English Longitudinal Study of Ageing (ELSA) cohort (2004/5-2014/15). The sample comprised of 215 participants who had sustained a hip fracture. Measures of social isolation and loneliness were analysed through multilevel modelling to determine their trajectories during three-time intervals (pre-fracture; interval at hip fracture and recovery; minimum 2 years post-fracture). The prevalence of social isolation and loneliness were determined pre- and post-fracture. prevalence of social isolation was 19% post-hip fracture and loneliness 13% post-hip fracture. There was no statistically significant change in social isolation pre-fracture compared to a minimum of 2 years post-fracture (P = 0.78). Similarly, there was no statistically significant change in loneliness pre-fracture compared to a minimum of 2 years post-fracture (P = 0.12). this analysis has determined that whilst social isolation and loneliness do not change over time following hip fracture, these remain a significant problem for this population. Interventions are required to address these physical and psychological health needs. This is important as they may have short and longer term health benefits for people post-hip fracture. © The Author 2017. Published by Oxford University Press on behalf of the British Geriatrics Society.All rights reserved. For permissions, please email: journals.permissions@oup.com

In Situ Fracture of Stents Implanted for Relief of Pulmonary Arterial Stenosis in Patients with Congenitally Malformed Hearts

PubMed Central

McElhinney, Doff B.; Bergersen, Lisa; Marshall, Audrey C.

2014-01-01

Background One of the most common uses of stents in patients with congenitally malformed hearts is treatment of pulmonary arterial stenosis. Although there are reports of fractured pulmonary arterial stents, little is known about the risk factors for, and implications of, such fractures. Methods We reviewed angiograms to identify fractures in stents previously inserted to relieve stenoses in pulmonary arteries from 1990 through 2001 in patients who also underwent follow-up catheterization at least 3 years after placement of the stent. We undertook matched cohort analysis, matching a ratio of 2 fractured to 1 unfractured stent. Results Overall, 166 stents meeting the criterions of our study had been placed in 120 patients. We identified fractures in 35 stents (21%) in 29 patients. All fractured stents were in the central pulmonary arteries, 24 (69%) in the central part of the right pulmonary artery, and all were complete axial fractures, or complex fractures along at least 2 planes. Stent-related factors associated with increased risk of fracture identified by multivariable logistic regression included placement in close apposition to the ascending aorta (p = 0.001), and a larger expanded diameter (p = 0.002). There was obstruction across 28 of 35 fractured stents, which was severe in 11. We re-stented 21 of the fractured stents, and recurrent fracture was later diagnosed in 3 of these. A fragment of the fractured stent embolized distally in 2 patients, without clinically important effects. Conclusions In situ fracture of pulmonary arterial stents is relatively common, and in most cases is related to compression by the aorta. There is usually recurrent obstruction across the fractured stent, but fractured stents rarely embolize, and are not associated with other significant complications. PMID:18559137

Optimizing for Large Planar Fractures in Multistage Horizontal Wells in Enhanced Geothermal Systems Using a Coupled Fluid and Geomechanics Simulator

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

Hu, Xiexiaomen; Tutuncu, Azra; Eustes, Alfred

Enhanced Geothermal Systems (EGS) could potentially use technological advancements in coupled implementation of horizontal drilling and multistage hydraulic fracturing techniques in tight oil and shale gas reservoirs along with improvements in reservoir simulation techniques to design and create EGS reservoirs. In this study, a commercial hydraulic fracture simulation package, Mangrove by Schlumberger, was used in an EGS model with largely distributed pre-existing natural fractures to model fracture propagation during the creation of a complex fracture network. The main goal of this study is to investigate optimum treatment parameters in creating multiple large, planar fractures to hydraulically connect a horizontal injectionmore » well and a horizontal production well that are 10,000 ft. deep and spaced 500 ft. apart from each other. A matrix of simulations for this study was carried out to determine the influence of reservoir and treatment parameters on preventing (or aiding) the creation of large planar fractures. The reservoir parameters investigated during the matrix simulations include the in-situ stress state and properties of the natural fracture set such as the primary and secondary fracture orientation, average fracture length, and average fracture spacing. The treatment parameters investigated during the simulations were fluid viscosity, proppant concentration, pump rate, and pump volume. A final simulation with optimized design parameters was performed. The optimized design simulation indicated that high fluid viscosity, high proppant concentration, large pump volume and pump rate tend to minimize the complexity of the created fracture network. Additionally, a reservoir with 'friendly' formation characteristics such as large stress anisotropy, natural fractures set parallel to the maximum horizontal principal stress (SHmax), and large natural fracture spacing also promote the creation of large planar fractures while minimizing fracture complexity.« less

"Buckle" rib fracture: an artifact following cardio-pulmonary resuscitation detected on postmortem CT.

PubMed

Yang, Kyung-Moo; Lynch, Matthew; O'Donnell, Chris

2011-09-01

Buckle rib fractures are incomplete fractures involving the inner cortex alone, and are rarely detected on routine chest X-ray or at autopsy. The characteristics of these fractures have not been well evaluated in situ although they are commonly observed on postmortem CT images especially following CPR. The postmortem CT findings in 42 cases showing buckle rib fractures caused by CPR were reviewed. The cause of death in all cases was non-traumatic. The shape, number, location, and distribution of these buckle rib fractures and their relationship to other types of rib fractures were evaluated using a novel oblique axial multiplanar reconstruction technique. Almost all incomplete rib fractures associated with CPR are buckle rib fractures (90.5%). All rib fractures were distributed from the second to ninth ribs with over 95% being within the second to seventh ribs. Buckle rib fractures are dominant in the seventh to ninth ribs and the proportion of buckle rib fractures located in the vicinity of the costochondral junctions increases with the lower ribs. Over 97% of all CPR associated rib fractures are located in the anterior one third of the ribs based on a new measurement method utilizing oblique axial multiplanar reconstruction of the CT data. When recognition of incomplete or buckle rib fractures on postmortem CT is taken into account, detection of symmetry and continuity of rib fractures typically associated with CPR is improved compared with the detection of complete fractures alone. Recognition of buckle rib fractures and their characteristics on postmortem CT is of benefit to the forensic pathologist in evaluating the possibility of CPR and the differentiation of resuscitative artifact from forensically significant visceral injury observed at autopsy. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Empirically Based Composite Fracture Prediction Model From the Global Longitudinal Study of Osteoporosis in Postmenopausal Women (GLOW)

PubMed Central

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

2014-01-01

Context: Several fracture prediction models that combine fractures at different sites into a composite outcome are in current use. However, to the extent individual fracture sites have differing risk factor profiles, model discrimination is impaired. Objective: The objective of the study was to improve model discrimination by developing a 5-year composite fracture prediction model for fracture sites that display similar risk profiles. Design: This was a prospective, observational cohort study. Setting: The study was conducted at primary care practices in 10 countries. Patients: Women aged 55 years or older participated in the study. Intervention: Self-administered questionnaires collected data on patient characteristics, fracture risk factors, and previous fractures. Main Outcome Measure: The main outcome is time to first clinical fracture of hip, pelvis, upper leg, clavicle, or spine, each of which exhibits a strong association with advanced age. Results: Of four composite fracture models considered, model discrimination (c index) is highest for an age-related fracture model (c index of 0.75, 47 066 women), and lowest for Fracture Risk Assessment Tool (FRAX) major fracture and a 10-site model (c indices of 0.67 and 0.65). The unadjusted increase in fracture risk for an additional 10 years of age ranges from 80% to 180% for the individual bones in the age-associated model. Five other fracture sites not considered for the age-associated model (upper arm/shoulder, rib, wrist, lower leg, and ankle) have age associations for an additional 10 years of age from a 10% decrease to a 60% increase. Conclusions: After examining results for 10 different bone fracture sites, advanced age appeared the single best possibility for uniting several different sites, resulting in an empirically based composite fracture risk model. PMID:24423345

Increasing number of fractured ribs is not predictive of the severity of splenic injury following blunt trauma: an analysis of a National Trauma Registry database.

PubMed

Boris, Kessel; Forat, Swaid; Itamar, Ashkenazi; Oded, Olsha; Kobi, Peleg; Adi, Givon; Igor, Jeroukhimov; Ricardo, Alfici

2014-05-01

Association between rib fractures and incidence of abdominal solid organs injury is well described. However, the correlation between the number of fractured ribs and severity of splenic injury is not clear. The purpose of this study was to assess whether an increasing number of rib fractures predicts the severity of splenic injury in blunt trauma patients. A retrospective cohort study involving blunt trauma patients with concomitant splenic injuries and rib fractures, between the years 1998 and 2012, registered in the Israeli National Trauma Registry. Of 321,618 patients with blunt mechanism of trauma, 57,130 had torso injuries, and of these 14,651 patients sustained rib fractures, and 3691 patients suffered from splenic injury. Concomitant splenic injury occurred in 1326 of the patients with rib fractures (9.1%), as compared to 2365 patients sustaining splenic injury without rib fractures (5.6%). The incidence of splenic injury among patients sustaining 5 or more rib fractures was significantly higher compared to patients suffering from 1 to 4 rib fractures. Among patients with splenic injury, the tendency to sustain associated rib fractures increased steadily with age. Patients with concomitant rib fractures had higher Injury Severity Score (ISS), but similar mortality rates, compared to patients with splenic injury without rib fractures. Among patients with concomitant rib fractures and splenic injury, there was no relation between the number of fractured ribs and the severity of splenic injury, neither as a whole group, nor after stratification according to the mechanism of injury. Although the presence of rib fractures increases the probability of splenic injury in blunt torso trauma, there is no relation between the number of fractured ribs and splenic injury severity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of isolated fractures on accelerated flow in unsaturated porous rock

USGS Publications Warehouse

Su, Grace W.; Nimmo, John R.; Dragila, Maria I.

2003-01-01

Fractures that begin and end in the unsaturated zone, or isolated fractures, have been ignored in previous studies because they were generally assumed to behave as capillary barriers and remain nonconductive. We conducted a series of experiments using Berea sandstone samples to examine the physical mechanisms controlling flow in a rock containing a single isolated fracture. The input fluxes and fracture orientation were varied in these experiments. Visualization experiments using dyed water in a thin vertical slab of rock were conducted to identify flow mechanisms occurring due to the presence of the isolated fracture. Two mechanisms occurred: (1) localized flow through the rock matrix in the vicinity of the isolated fracture and (2) pooling of water at the bottom of the fracture, indicating the occurrence of film flow along the isolated fracture wall. These mechanisms were observed at fracture angles of 20 and 60 degrees from the horizontal, but not at 90 degrees. Pooling along the bottom of the fracture was observed over a wider range of input fluxes for low‐angled isolated fractures compared to high‐angled ones. Measurements of matrix water pressures in the samples with the 20 and 60 degree fractures also demonstrated that preferential flow occurred through the matrix in the fracture vicinity, where higher pressures occurred in the regions where faster flow was observed in the visualization experiments. The pooling length at the terminus of a 20 degree isolated fracture was measured as a function of input flux. Calculations of the film flow rate along the fracture were made using these measurements and indicated that up to 22% of the flow occurred as film flow. These experiments, apparently the first to consider isolated fractures, demonstrate that such features can accelerate flow through the unsaturated zone and should be considered when developing conceptual models.

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.

Fragility non-hip fracture patients are at risk.

PubMed

Gosch, M; Druml, T; Nicholas, J A; Hoffmann-Weltin, Y; Roth, T; Zegg, M; Blauth, M; Kammerlander, C

2015-01-01

Fragility fractures are a growing worldwide health care problem. Hip fractures have been clearly associated with poor outcomes. Fragility fractures of other bones are common reasons for hospital admission and short-term disability, but specific long-term outcome studies of non-hip fragility fractures are rare. The aim of our trial was to evaluate the 1-year outcomes of non-hip fragility fracture patients. This study is a retrospective cohort review of 307 consecutive older inpatient non-hip fracture patients. Patient data for analysis included fracture location, comorbidity prevalence, pre-fracture functional status, osteoporosis treatments and sociodemographic characteristics. The main outcomes evaluated were 1-year mortality and post-fracture functional status. As compared to the expected mortality, the observed 1-year mortality was increased in the study group (17.6 vs. 12.2 %, P = 0.005). After logistic regression, three variables remained as independent risk factors for 1-year mortality among non-hip fracture patients: malnutrition (OR 3.3, CI 1.5-7.1), Charlson comorbidity index (CCI) (OR 1.3, CI 1.1-1.5) and the Parker Mobility Score (PMS) (OR 0.85, CI 0.74-0.98). CCI and PMS were independent risk factors for a high grade of dependency after 1 year. Management of osteoporosis did not significantly improve after hospitalization due to a non-hip fragility fracture. The outcomes of older non-hip fracture patients are comparable to the poor outcomes of older hip fracture patients, and appear to be primarily related to comorbidities, pre-fracture function and nutritional status. The low rate of patients on osteoporosis medications likely reflects the insufficient recognition of the importance of osteoporosis assessment and treatment in non-hip fracture patients. Increased clinical and academic attention to non-hip fracture patients is needed.

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.

Evidence for tectonic, lithologic, and thermal controls on fracture system geometries in an andesitic high-temperature geothermal field

NASA Astrophysics Data System (ADS)

Massiot, Cécile; Nicol, Andrew; McNamara, David D.; Townend, John

2017-08-01

Analysis of fracture orientation, spacing, and thickness from acoustic borehole televiewer (BHTV) logs and cores in the andesite-hosted Rotokawa geothermal reservoir (New Zealand) highlights potential controls on the geometry of the fracture system. Cluster analysis of fracture orientations indicates four fracture sets. Probability distributions of fracture spacing and thickness measured on BHTV logs are estimated for each fracture set, using maximum likelihood estimations applied to truncated size distributions to account for sampling bias. Fracture spacing is dominantly lognormal, though two subordinate fracture sets have a power law spacing. This difference in spacing distributions may reflect the influence of the andesitic sequence stratification (lognormal) and tectonic faults (power law). Fracture thicknesses of 9-30 mm observed in BHTV logs, and 1-3 mm in cores, are interpreted to follow a power law. Fractures in thin sections (˜5 μm thick) do not fit this power law distribution, which, together with their orientation, reflect a change of controls on fracture thickness from uniform (such as thermal) controls at thin section scale to anisotropic (tectonic) at core and BHTV scales of observation. However, the ˜5% volumetric percentage of fractures within the rock at all three scales suggests a self-similar behavior in 3-D. Power law thickness distributions potentially associated with power law fluid flow rates, and increased connectivity where fracture sets intersect, may cause the large permeability variations that occur at hundred meter scales in the reservoir. The described fracture geometries can be incorporated into fracture and flow models to explore the roles of fracture connectivity, stress, and mineral precipitation/dissolution on permeability in such andesite-hosted geothermal systems.

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.

Clinical, retrospective case-control study on the mechanics of obstacle in mouth opening and malocclusion in patients with maxillofacial fractures.

PubMed

Zhou, Hai-Hua; Lv, Kun; Yang, Rong-Tao; Li, Zhi; Yang, Xue-Wen; Li, Zu-Bing

2018-05-16

This study aims to identify and distinguish various factors that may influence the clinical symptoms (limited mouth opening and malocclusion) in patients with maxillofacial fractures. From January 2000 to December 2009, 963 patients with maxillofacial fractures were enrolled in this statistical study to aid in evaluating the association between various risk factors and clinical symptoms. Patients with fractured posterior mandibles tended to experience serious limitation in mouth opening. Patients who sustained coronoid fractures have the highest risk of serious limitation in mouth opening (OR = 9.849), followed by arch fractures, maxilla fractures, condylar fractures, zygomatic complex fractures and symphysis fractures. Meanwhile, the combined fracture of zygomatic arch and condylar process results in normal or mild mouth opening. High risks of sustaining malocclusion are preceded by the fracture of nasal bone (OR = 3.067), mandible, condylar neck/base, combined fracture of zygomatic arch and condylar process, mandibular body, bilateral condylar, dental trauma, mandibular ramus, symphysis, mandibular angle and mid-facial. Patients who experienced serious limitation in mouth opening are treated with surgery more frequently (OR = 2.118). No relationship exists between the treatment options and the patients with malocclusion.

CT scanning and flow measurements of shale fractures after multiple shearing events

DOE PAGES

Crandall, Dustin; Moore, Johnathan; Gill, Magdalena; ...

2017-11-05

A shearing apparatus was used in conjunction with a Hassler-style core holder to incrementally shear fractured shale cores while maintaining various confining pressures. Computed tomography scans were performed after each shearing event, and were used to obtain information on evolving fracture geometry. Fracture transmissivity was measured after each shearing event to understand the hydrodynamic response to the evolving fracture structure. The digital fracture volumes were used to perform laminar single phase flow simulations (local cubic law with a tapered plate correction model) to qualitatively examine small scale flow path variations within the altered fractures. Fractures were found to generally increasemore » in aperture after several shear slip events, with corresponding transmissivity increases. Lower confining pressure resulted in a fracture more prone to episodic mechanical failure and sudden changes in transmissivity. Conversely, higher confining pressures resulted in a system where, after an initial setting of the fracture surfaces, changes to the fracture geometry and transmissivity occurred gradually. Flow paths within the fractures are largely controlled by the location and evolution of zero aperture locations. Lastly, a reduction in the number of primary flow pathways through the fracture, and an increase in their width, was observed during all shearing tests.« less

Rib fractures and their association With solid organ injury: higher rib fractures have greater significance for solid organ injury screening.

PubMed

Rostas, Jack W; Lively, Timothy B; Brevard, Sidney B; Simmons, Jon D; Frotan, Mohammad A; Gonzalez, Richard P

2017-04-01

The purpose of this study was to identify patients with rib injuries who were at risk for solid organ injury. A retrospective chart review was performed of all blunt trauma patients with rib fractures during the period from July 2007 to July 2012. Data were analyzed for association of rib fractures and solid organ injury. In all, 1,103 rib fracture patients were identified; 142 patients had liver injuries with 109 (77%) associated right rib fractures. Right-sided rib fractures with highest sensitivity for liver injury were middle rib segment (5 to 8) and lower segment (9 to 12) with liver injury sensitivities of 68% and 43%, respectively (P < .001); 151 patients had spleen injuries with 119 (79%) associated left rib fractures. Left middle segment rib fractures and lower segment rib fractures had sensitivities of 80% and 63% for splenic injury, respectively (P < .003). Rib fractures higher in the thoracic cage have significant association with solid organ injury. Using rib fractures from middle plus lower segments as indication for abdominal screening will significantly improve rib fracture sensitivity for identification of solid organ injury. Copyright © 2016 Elsevier Inc. All rights reserved.

Initiation and propagation of mixed mode fractures in granite and sandstone

NASA Astrophysics Data System (ADS)

Rück, Marc; Rahner, Roman; Sone, Hiroki; Dresen, Georg

2017-10-01

We investigate mixed mode fracture initiation and propagation in experimentally deformed granite and sandstone. We performed a series of asymmetric loading tests to induce fractures in cylindrical specimens at confining pressures up to 20 MPa. Loading was controlled using acoustic emission (AE) feedback control, which allows studying quasi-static fracture propagation for several hours. Location of acoustic emissions reveals distinct differences in spatial-temporal fracture evolution between granite and sandstone samples. Before reaching peak stress in experiments performed on granite, axial fractures initiate first at the edge of the indenter and then propagate through the entire sample. Secondary inclined fractures develop during softening of the sample. In sandstone, inclined shear fractures nucleate at peak stress and propagate through the specimen. AE source type analysis shows complex fracturing in both materials with pore collapse contributing significantly to fracture growth in sandstone samples. We compare the experimental results with numerical models to analyze stress distribution and energy release rate per unit crack surface area in the samples at different stages during fracture growth. We thereby show that for both rock types the energy release rate increases approximately linearly during fracture propagation. The study illuminates how different material properties modify fracture initiation direction under similar loading conditions.

Unexpected timely fracture union in matrix metalloproteinase 9 deficient mice.

PubMed

Yuasa, Masato; Saito, Masanori; Molina, Cesar; Moore-Lotridge, Stephanie N; Benvenuti, Michael A; Mignemi, Nicholas A; Okawa, Atsushi; Yoshii, Toshitaka; Schwartz, Herbert S; Nyman, Jeffry S; Schoenecker, Jonathan G

2018-01-01

Immediately following a fracture, a fibrin laden hematoma is formed to prevent bleeding and infection. Subsequently, the organized removal of fibrin, via the protease plasmin, is essential to permit fracture repair through angiogenesis and ossification. Yet, when plasmin activity is lost, the depletion of fibrin alone is insufficient to fully restore fracture repair, suggesting the existence of additional plasmin targets important for fracture repair. Previously, activated matrix metalloproteinase 9 (MMP-9) was demonstrated to function in fracture repair by promoting angiogenesis. Given that MMP-9 is a defined plasmin target, it was hypothesized that pro-MMP-9, following plasmin activation, promotes fracture repair. This hypothesis was tested in a fixed murine femur fracture model with serial assessment of fracture healing. Contrary to previous findings, a complete loss of MMP-9 failed to affect fracture healing and union through 28 days post injury. Therefore, these results demonstrated that MMP-9 is dispensable for timely fracture union and cartilage transition to bone in fixed femur fractures. Pro-MMP-9 is therefore not a significant target of plasmin in fracture repair and future studies assessing additional plasmin targets associated with angiogenesis are warranted.

Detection of Natural Fractures from Observed Surface Seismic Data Based on a Linear-Slip Model

NASA Astrophysics Data System (ADS)

Chen, Huaizhen; Zhang, Guangzhi

2018-03-01

Natural fractures play an important role in migration of hydrocarbon fluids. Based on a rock physics effective model, the linear-slip model, which defines fracture parameters (fracture compliances) for quantitatively characterizing the effects of fractures on rock total compliance, we propose a method to detect natural fractures from observed seismic data via inversion for the fracture compliances. We first derive an approximate PP-wave reflection coefficient in terms of fracture compliances. Using the approximate reflection coefficient, we derive azimuthal elastic impedance as a function of fracture compliances. An inversion method to estimate fracture compliances from seismic data is presented based on a Bayesian framework and azimuthal elastic impedance, which is implemented in a two-step procedure: a least-squares inversion for azimuthal elastic impedance and an iterative inversion for fracture compliances. We apply the inversion method to synthetic and real data to verify its stability and reasonability. Synthetic tests confirm that the method can make a stable estimation of fracture compliances in the case of seismic data containing a moderate signal-to-noise ratio for Gaussian noise, and the test on real data reveals that reasonable fracture compliances are obtained using the proposed method.

CT scanning and flow measurements of shale fractures after multiple shearing events

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

Crandall, Dustin; Moore, Johnathan; Gill, Magdalena

A shearing apparatus was used in conjunction with a Hassler-style core holder to incrementally shear fractured shale cores while maintaining various confining pressures. Computed tomography scans were performed after each shearing event, and were used to obtain information on evolving fracture geometry. Fracture transmissivity was measured after each shearing event to understand the hydrodynamic response to the evolving fracture structure. The digital fracture volumes were used to perform laminar single phase flow simulations (local cubic law with a tapered plate correction model) to qualitatively examine small scale flow path variations within the altered fractures. Fractures were found to generally increasemore » in aperture after several shear slip events, with corresponding transmissivity increases. Lower confining pressure resulted in a fracture more prone to episodic mechanical failure and sudden changes in transmissivity. Conversely, higher confining pressures resulted in a system where, after an initial setting of the fracture surfaces, changes to the fracture geometry and transmissivity occurred gradually. Flow paths within the fractures are largely controlled by the location and evolution of zero aperture locations. Lastly, a reduction in the number of primary flow pathways through the fracture, and an increase in their width, was observed during all shearing tests.« less

Surgical repair of femoral fractures in New World camelids: five cases (1996-2003).

PubMed

Shoemaker, R W; Wilson, D G

2007-04-01

Five New World camelids were admitted to the Western College of Veterinary Medicine between 1996 and 2003 for evaluation of femoral fractures. There were three alpacas and two llamas. Four of the animals were female and three were less than 3 months of age. Fracture configurations consisted of distal physeal fractures (three), a comminuted diaphyseal/metaphyseal fracture, and a transverse diaphyseal fracture. Fractures were diagnosed with a combination of physical examination and radiographs in all cases. All five fractures were repaired with internal fixation and three animals were discharged from the hospital with fractures that healed. One cria underwent successful internal fixation but died from pulmonary oedema during recovery from anaesthesia. Postoperative complications were rare and limited to inadequate fracture stability in one alpaca and prolonged recovery to weight bearing in another. One llama with a comminuted metaphyseal fracture, repaired with a 4.5 mm dynamic compression plate, subsequently had catastrophic failure of the bone 17 days after surgery. Overall the clients were pleased with the outcome of discharged animals. Although femoral fractures are considered rare, they pose a unique opportunity for the large animal veterinarian to successfully achieve fracture union with the aid of internal fixation.

Prevalence of overweight in children with bone fractures: a case control study.

PubMed

Valerio, Giuliana; Gallè, Francesca; Mancusi, Caterina; Di Onofrio, Valeria; Guida, Pasquale; Tramontano, Antonino; Ruotolo, Edoardo; Liguori, Giorgio

2012-10-22

Children's fractures have been enlisted among orthopaedics complaints of childhood obesity. Unhealthy lifestyle behaviours may contribute to increased risk. This study described the prevalence of overweight/obesity in children and adolescents reporting a recent fracture in relation to gender, dynamic of trauma, and site of fracture. Four-hundred-forty-nine children and adolescents with fracture and 130 fracture-free controls were recruited from a large children's hospital. The interaction between overweight and gender, dynamic of trauma, site of fracture was explored. Sports participation, television viewing, and calcium intake were also investigated. Overweight/obesity rate was increased in girls with fracture either at the upper or the lower limb (p= 0.004), while it was increased only in boys with fracture at the lower limb (p <0.02). Overweight/obesity rate did not differ between groups with low or moderate trauma. TV viewing ≥ 2 hrs was more frequent in children with fractures than controls (61.5% vs 34.5%, p =0.015) in the overweight/obese group. The increased prevalence of overweight/obesity in children with fractures is related to gender and site of fracture. Higher levels of sedentary behaviours characterize overweight children reporting fractures.

Prevalence of overweight in children with bone fractures: a case control study

PubMed Central

2012-01-01

Background Children's fractures have been enlisted among orthopaedics complaints of childhood obesity. Unhealthy lifestyle behaviours may contribute to increased risk. This study described the prevalence of overweight/obesity in children and adolescents reporting a recent fracture in relation to gender, dynamic of trauma, and site of fracture. Methods Four-hundred-forty-nine children and adolescents with fracture and 130 fracture-free controls were recruited from a large children’s hospital. The interaction between overweight and gender, dynamic of trauma, site of fracture was explored. Sports participation, television viewing, and calcium intake were also investigated. Results Overweight/obesity rate was increased in girls with fracture either at the upper or the lower limb (p= 0.004), while it was increased only in boys with fracture at the lower limb (p <0.02). Overweight/obesity rate did not differ between groups with low or moderate trauma. TV viewing ≥ 2 hrs was more frequent in children with fractures than controls (61.5% vs 34.5%, p =0.015) in the overweight/obese group. Conclusions The increased prevalence of overweight/obesity in children with fractures is related to gender and site of fracture. Higher levels of sedentary behaviours characterize overweight children reporting fractures. PMID:23088687

Occupational exposures among nurses and risk of spontaneous abortion

PubMed Central

LAWSON, Christina C; ROCHELEAU, Carissa M.; WHELAN, Elizabeth A; LIVIDOTI HIBERT, Eileen N.; GRAJEWSKI, Barbara; SPIEGELMAN, Donna; RICH-EDWARDS, Janet W.

2015-01-01

Objective We investigated self-reported occupational exposure to antineoplastic drugs, anesthetic gases, antiviral drugs, sterilizing agents (disinfectants), and X-rays and the risk of spontaneous abortion in U.S. nurses. Study Design Pregnancy outcome and occupational exposures were collected retrospectively from 8,461 participants of the Nurses’ Health Study II. Of these, 7,482 were eligible for analysis using logistic regression. Results Participants reported 6,707 live births, and 775 (10%) spontaneous abortions (<20 weeks). After adjusting for age, parity, shift work, and hours worked, antineoplastic drug exposure was associated with a 2-fold increased risk of spontaneous abortion, particularly with early spontaneous abortion before the 12th week, and 3.5-fold increased risk among nulliparous women. Exposure to sterilizing agents was associated with a 2-fold increased risk of late spontaneous abortion (12–20 weeks), but not with early spontaneous abortion. Conclusion This study suggests that certain occupational exposures common to nurses are related to risks of spontaneous abortion. PMID:22304790

Residual lifetime and 10 year absolute risks of osteoporotic fractures in Chinese men and women.

PubMed

Si, Lei; Winzenberg, Tania M; Chen, Mingsheng; Jiang, Qicheng; Palmer, Andrew J

2015-06-01

To determine the residual lifetime and 10 year absolute risks of osteoporotic fractures in Chinese men and women. A validated state-transition microsimulation model was used. Microsimulation and probabilistic sensitivity analyses were performed to address the uncertainties in the model. All parameters including fracture incidence rates and mortality rates were retrieved from published literature. Simulated subjects were run through the model until they died to estimate the residual lifetime fracture risks. A 10 year time horizon was used to determine the 10 year fracture risks. We estimated the risk of only the first osteoporotic fracture during the simulation time horizon. The residual lifetime and 10 year risks of having the first osteoporotic (hip, clinical vertebral or wrist) fracture for Chinese women aged 50 years were 40.9% (95% CI: 38.3-44.0%) and 8.2% (95% CI: 6.8-9.3%) respectively. For men, the residual lifetime and 10 year fracture risks were 8.7% (95% CI: 7.5-9.8%) and 1.2% (95% CI: 0.8-1.7%) respectively. The residual lifetime fracture risks declined with age, whilst the 10 year fracture risks increased with age until the short-term mortality risks outstripped the fracture risks. Residual lifetime and 10 year clinical vertebral fracture risks were higher than those of hip and wrist fractures in both sexes. More than one third of the Chinese women and approximately one tenth of the Chinese men aged 50 years are expected to sustain a major osteoporotic fracture in their remaining lifetimes. Due to increased fracture risks and a rapidly ageing population, osteoporosis will present a great challenge to the Chinese healthcare system. While national data was used wherever possible, regional Chinese hip and clinical vertebral fracture incidence rates were used, wrist fracture rates were taken from a Norwegian study and calibrated to the Chinese population. Other fracture sites like tibia, humerus, ribs and pelvis were not included in the analysis, thus these risks are likely to be underestimates. Fracture risk factors other than age and sex were not included in the model. Point estimates were used for fracture incidence rates, osteoporosis prevalence and mortality rates for the general population.

Foal Fractures: Osteochondral Fragmentation, Proximal Sesamoid Bone Fractures/Sesamoiditis, and Distal Phalanx Fractures.

PubMed

Reesink, Heidi L

2017-08-01

Foals are susceptible to many of the same types of fractures as adult horses, often secondary to external sources of trauma. In addition, some types of fractures are specific to foals and occur routinely in horses under 1 year of age. These foal-specific fractures may be due to the unique musculoskeletal properties of the developing animal and may present with distinct clinical signs. Treatment plans and prognoses are tailored specifically to young animals. Common fractures not affecting the long bones in foals are discussed in this article, including osteochondral fragmentation, proximal sesamoid bone fractures/sesamoiditis, and distal phalanx fractures. Copyright © 2017 Elsevier Inc. All rights reserved.

Pattern of Cortical Fracture following Corticotomy for Distraction Osteogenesis.

PubMed

Luvan, M; Kanthan, S R; Roshan, G; Saw, A

2015-11-01

Corticotomy is an essential procedure for deformity correction and there are many techniques described. However there is no proper classification of the fracture pattern resulting from corticotomies to enable any studies to be conducted. We performed a retrospective study of corticotomy fracture patterns in 44 patients (34 tibias and 10 femurs) performed for various indications. We identified four distinct fracture patterns, Type I through IV classification based on the fracture propagation following percutaneous corticotomy. Type I transverse fracture, Type II transverse fracture with a winglet, Type III presence of butterfly fragment and Type IV fracture propagation to a fixation point. No significant correlation was noted between the fracture pattern and the underlying pathology or region of corticotomy.

Tympanic plate fractures in temporal bone trauma: prevalence and associated injuries.

PubMed

Wood, C P; Hunt, C H; Bergen, D C; Carlson, M L; Diehn, F E; Schwartz, K M; McKenzie, G A; Morreale, R F; Lane, J I

2014-01-01

The prevalence of tympanic plate fractures, which are associated with an increased risk of external auditory canal stenosis following temporal bone trauma, is unknown. A review of posttraumatic high-resolution CT temporal bone examinations was performed to determine the prevalence of tympanic plate fractures and to identify any associated temporal bone injuries. A retrospective review was performed to evaluate patients with head trauma who underwent emergent high-resolution CT examinations of the temporal bone from July 2006 to March 2012. Fractures were identified and assessed for orientation; involvement of the tympanic plate, scutum, bony labyrinth, facial nerve canal, and temporomandibular joint; and ossicular chain disruption. Thirty-nine patients (41.3 ± 17.2 years of age) had a total of 46 temporal bone fractures (7 bilateral). Tympanic plate fractures were identified in 27 (58.7%) of these 46 fractures. Ossicular disruption occurred in 17 (37.0%). Fractures involving the scutum occurred in 25 (54.4%). None of the 46 fractured temporal bones had a mandibular condyle dislocation or fracture. Of the 27 cases of tympanic plate fractures, 14 (51.8%) had ossicular disruption (P = .016) and 18 (66.6%) had a fracture of the scutum (P = .044). Temporomandibular joint gas was seen in 15 (33%) but was not statistically associated with tympanic plate fracture (P = .21). Tympanic plate fractures are commonly seen on high-resolution CT performed for evaluation of temporal bone trauma. It is important to recognize these fractures to avoid the preventable complication of external auditory canal stenosis and the potential for conductive hearing loss due to a fracture involving the scutum or ossicular chain.

An analytical model for hydraulic fracturing in shallow bedrock formations.

PubMed

dos Santos, José Sérgio; Ballestero, Thomas Paul; Pitombeira, Ernesto da Silva

2011-01-01

A theoretical method is proposed to estimate post-fracturing fracture size and transmissivity, and as a test of the methodology, data collected from two wells were used for verification. This method can be employed before hydrofracturing in order to obtain estimates of the potential hydraulic benefits of hydraulic fracturing. Five different pumping test analysis methods were used to evaluate the well hydraulic data. The most effective methods were the Papadopulos-Cooper model (1967), which includes wellbore storage effects, and the Gringarten-Ramey model (1974), known as the single horizontal fracture model. The hydraulic parameters resulting from fitting these models to the field data revealed that as a result of hydraulic fracturing, the transmissivity increased more than 46 times in one well and increased 285 times in the other well. The model developed by dos Santos (2008), which considers horizontal radial fracture propagation from the hydraulically fractured well, was used to estimate potential fracture geometry after hydrofracturing. For the two studied wells, their fractures could have propagated to distances of almost 175 m or more and developed maximum apertures of about 2.20 mm and hydraulic apertures close to 0.30 mm. Fracturing at this site appears to have expanded and propagated existing fractures and not created new fractures. Hydraulic apertures calculated from pumping test analyses closely matched the results obtained from the hydraulic fracturing model. As a result of this model, post-fracturing geometry and resulting post-fracturing well yield can be estimated before the actual hydrofracturing. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

Deferoxamine restores callus size, mineralization, and mechanical strength in fracture healing after radiotherapy.

PubMed

Donneys, Alexis; Ahsan, Salman; Perosky, Joseph E; Deshpande, Sagar S; Tchanque-Fossuo, Catherine N; Levi, Benjamin; Kozloff, Ken M; Buchman, Steven R

2013-05-01

Therapeutic augmentation of fracture-site angiogenesis with deferoxamine has proven to increase vascularity, callus size, and mineralization in long-bone fracture models. The authors posit that the addition of deferoxamine would enhance pathologic fracture healing in the setting of radiotherapy in a model where nonunions are the most common outcome. Thirty-five Sprague-Dawley rats were divided into three groups. Fracture, irradiated fracture, and irradiated fracture plus deferoxamine. The irradiated fracture and irradiated fracture plus deferoxamine groups received a human equivalent dose of radiotherapy [7 Gy/day for 5 days, (35 Gy)] 2 weeks before mandibular osteotomy and external fixation. The irradiated fracture plus deferoxamine group received injections of deferoxamine into the fracture callus after surgery. After a 40-day healing period, mandibles were dissected, clinically assessed for bony union, imaged with micro-computed tomography, and tension tested to failure. Compared with irradiated fractures, metrics of callus size, mineralization, and strength in deferoxamine-treated mandibles were significantly increased. These metrics were restored to a level demonstrating no statistical difference from control fractures. In addition, the authors observed an increased rate of achieving bony unions in the irradiated fracture plus deferoxamine-treated group when compared with irradiated fracture (67 percent and 20 percent, respectively). The authors' data demonstrate nearly total restoration of callus size, mineralization, and biomechanical strength, and a threefold increase in the rate of union with the use of deferoxamine. The authors' results suggest that the administration of deferoxamine may have the potential for clinical translation as a new treatment paradigm for radiation-induced pathologic fractures.

Association between findings on palmarodorsal radiographic images and detection of a fracture in the proximal sesamoid bones of forelimbs obtained from cadavers of racing Thoroughbreds.

PubMed

Anthenill, Lucy A; Stover, Susan M; Gardner, Ian A; Hill, Ashley E; Lee, Christina M; Anderson, Mark L; Barr, Bradd C; Read, Deryck H; Johnson, Bill J; Woods, Leslie W; Daft, Barbara M; Kinde, Hailu; Moore, Janet D; Farman, Cynthia A; Odani, Jenee S; Pesavento, Patricia A; Uzal, Francisco A; Case, James T; Ardans, Alex A

2006-05-01

To determine the distribution for limbs and bones in horses with fractures of the proximal sesamoid bones and relationships with findings on palmarodorsal radiographic images. Proximal sesamoid bones obtained from both forelimbs of cadavers of 328 racing Thoroughbreds. Osteophytes; large vascular channels; and fracture location, orientation, configuration, and margin distinctness were categorized by use of high-detail contact palmarodorsal radiographs. Distributions of findings were determined. Relationships between radiographic findings and fracture characteristics were examined by use of chi2 and logistic regression techniques. Fractures were detected in 136 (41.5%) horses. Biaxial fractures were evident in 109 (80%) horses with a fracture. Osteophytes and large vascular channels were evident in 266 (81%) and 325 (99%) horses, respectively. Medial bones typically had complete transverse or split transverse simple fractures, indistinct fracture margins, > 1 vascular channel that was > 1 mm in width, and osteophytes in abaxial wing and basilar middle or basilar abaxial locations. Lateral bones typically had an oblique fracture and distinct fracture margins. Odds of proximal sesamoid bone fracture were approximately 2 to 5 times higher in bones without radiographic evidence of osteophytes or large vascular channels, respectively. Biaxial fractures of proximal sesamoid bones were common in cadavers of racing Thoroughbreds. Differences between medial and lateral bones for characteristics associated with fracture may relate to differences in fracture pathogeneses for these bones. Osteophytes and vascular channels were common findings; however, fractures were less likely to occur in bones with these features.

Predicting bulk permeability using outcrop fracture attributes: The benefits of a Maximum Likelihood Estimator

NASA Astrophysics Data System (ADS)

Rizzo, R. E.; Healy, D.; De Siena, L.

2015-12-01

The success of any model prediction is largely dependent on the accuracy with which its parameters are known. In characterising fracture networks in naturally fractured rocks, the main issues are related with the difficulties in accurately up- and down-scaling the parameters governing the distribution of fracture attributes. Optimal characterisation and analysis of fracture attributes (fracture lengths, apertures, orientations and densities) represents a fundamental step which can aid the estimation of permeability and fluid flow, which are of primary importance in a number of contexts ranging from hydrocarbon production in fractured reservoirs and reservoir stimulation by hydrofracturing, to geothermal energy extraction and deeper Earth systems, such as earthquakes and ocean floor hydrothermal venting. This work focuses on linking fracture data collected directly from outcrops to permeability estimation and fracture network modelling. Outcrop studies can supplement the limited data inherent to natural fractured systems in the subsurface. The study area is a highly fractured upper Miocene biosiliceous mudstone formation cropping out along the coastline north of Santa Cruz (California, USA). These unique outcrops exposes a recently active bitumen-bearing formation representing a geological analogue of a fractured top seal. In order to validate field observations as useful analogues of subsurface reservoirs, we describe a methodology of statistical analysis for more accurate probability distribution of fracture attributes, using Maximum Likelihood Estimators. These procedures aim to understand whether the average permeability of a fracture network can be predicted reducing its uncertainties, and if outcrop measurements of fracture attributes can be used directly to generate statistically identical fracture network models.

Post-fracture management of patients with hip fracture: a perspective.

PubMed

Bruyere, O; Brandi, M-L; Burlet, N; Harvey, N; Lyritis, G; Minne, H; Boonen, S; Reginster, J-Y; Rizzoli, R; Akesson, K

2008-10-01

Hip fracture creates a worldwide morbidity, mortality and economic burden. After surgery, many patients experience long-term disability or die as a consequence of the fracture. A fracture is a major risk factor for a subsequent fracture, which may occur within a short interval. A literature search on post-fracture management of patients with hip fracture was performed on the Medline database. Key experts convened to develop a consensus document. Management of hip-fracture patients to optimize outcome after hospital discharge requires several stages of care co-ordinated by a multidisciplinary team from before admission through to discharge. Further studies that specifically assess prevention and post-fracture management of hip fracture are needed, as only one study to date has assessed an osteoporosis medication in patients with a recent hip fracture. Proper nutrition is vital to assist bone repair and prevent further falls, particularly in malnourished patients. Vitamin D, calcium and protein supplementation is associated with an increase in hip BMD and reduction in falls. Rehabilitation is essential to improve functional disabilities and survival rates. Fall prevention and functional recovery strategies should include patient education and training to improve balance and increase muscle strength and mobility. Appropriate management can prevent further fractures and it is critical that high-risk patients are identified and treated. To foster this process, clinical pathways have been established to support orthopaedic surgeons. Although hip fracture is generally associated with poor outcomes, appropriate management can ensure optimal recovery and survival, and should be prioritized after a hip fracture to avoid deterioration of health and prevent subsequent fracture.

The AO Pediatric Comprehensive Classification of Long Bone Fractures (PCCF).

PubMed

Audigé, Laurent; Slongo, Theddy; Lutz, Nicolas; Blumenthal, Andrea; Joeris, Alexander

2017-04-01

Background and purpose - The AO Pediatric Comprehensive Classification of Long Bone Fractures (PCCF) describes the localization and morphology of fractures, and considers severity in 2 categories: (1) simple, and (2) multifragmentary. We evaluated simple and multifragmentary fractures in a large consecutive cohort of children diagnosed with long bone fractures in Switzerland. Patients and methods - Children and adolescents treated for fractures between 2009 and 2011 at 2 tertiary pediatric surgery hospitals were retrospectively included. Fractures were classified according to the AO PCCF. Severity classes were described according to fracture location, patient age and sex, BMI, and cause of trauma. Results - Of all trauma events, 3% (84 of 2,730) were diagnosed with a multifragmentary fracture. This proportion was age-related: 2% of multifragmentary fractures occurred in school-children and 7% occurred in adolescents. In patients diagnosed with a single fracture only, the highest percentage of multifragmentation occurred in the femur (12%, 15 of 123). In fractured paired radius/ulna bones, multifragmentation occurred in 2% (11 of 687); in fractured paired tibia/fibula bones, it occurred in 21% (24 of 115), particularly in schoolchildren (5 of 18) and adolescents (16 of 40). In a multivariable regression model, age, cause of injury, and bone were found to be relevant prognostic factors of multifragmentation (odds ratio (OR) > 2). Interpretation - Overall, multifragmentation in long bone fractures in children was rare and was mostly observed in adolescents. The femur was mostly affected in single fractures and the lower leg was mostly affected in paired-bone fractures. The clinical relevance of multifragmentation regarding growth and long-term functional recovery remains to be determined.

Incidence and epidemiology of tibial shaft fractures.

PubMed

Larsen, Peter; Elsoe, Rasmus; Hansen, Sandra Hope; Graven-Nielsen, Thomas; Laessoe, Uffe; Rasmussen, Sten

2015-04-01

The literature lacks recent population-based epidemiology studies of the incidence, trauma mechanism and fracture classification of tibial shaft fractures. The purpose of this study was to provide up-to-date information on the incidence of tibial shaft fractures in a large and complete population and report the distribution of fracture classification, trauma mechanism and patient baseline demographics. Retrospective reviews of clinical and radiological records. A total of 196 patients were treated for 198 tibial shaft fractures in the years 2009 and 2010. The mean age at time of fracture was 38.5 (21.2SD) years. The incidence of tibial shaft fracture was 16.9/100,000/year. Males have the highest incidence of 21.5/100,000/year and present with the highest frequency between the age of 10 and 20, whereas women have a frequency of 12.3/100,000/year and have the highest frequency between the age of 30 and 40. AO-type 42-A1 was the most common fracture type, representing 34% of all tibial shaft fractures. The majority of tibial shaft fractures occur during walking, indoor activity and sports. The distribution among genders shows that males present a higher frequency of fractures while participating in sports activities and walking. Women present the highest frequency of fractures while walking and during indoor activities. This study shows an incidence of 16.9/100,000/year for tibial shaft fractures. AO-type 42-A1 was the most common fracture type, representing 34% of all tibial shaft fractures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Brain-derived neurotrophic factor is increased in serum and skin levels of patients with chronic spontaneous urticaria.

PubMed

Rössing, K; Novak, N; Mommert, S; Pfab, F; Gehring, M; Wedi, B; Kapp, A; Raap, U

2011-10-01

Chronic spontaneous urticaria is triggered by many direct and indirect aggravating factors including autoreactive/autoimmune mechanisms, infections, non-allergic and pseudoallergic intolerance reactions. However, the role of neuroimmune mechanisms in chronic spontaneous urticaria so far is unclear. Thus, we wanted to address the regulation of the neurotrophin brain-derived neurotrophic factor (BDNF) in serum and inflammatory skin of patients with chronic spontaneous urticaria in comparison to subjects with healthy skin. Fifty adult patients with chronic spontaneous urticaria and 23 skin-healthy subjects were studied. Chronic spontaneous urticaria was defined as recurrent weals for more than 6 weeks. Autologous serum skin test was performed in all patients with chronic spontaneous urticaria and BDNF serum levels were analysed by enzyme immunoassay in all subjects. Furthermore, skin biopsies were taken from weals of eight patients with chronic spontaneous urticaria as well as from healthy skin of eight controls to evaluate the expression of BDNF and its receptors including tyrosine kinase (trk) B and pan-neurotrophin receptor p75(NTR) by immunohistochemistry. BDNF serum levels were detectable in all subjects studied. However, BDNF levels were significantly higher in patients with chronic spontaneous urticaria compared to non-atopic skin-healthy controls (P<0.001). Furthermore, epidermal and dermal expression of BDNF and epidermal expression of p75(NTR) was significantly higher in patients with chronic spontaneous urticaria compared with controls (P<0.05-0.001). There was no difference with regard to the expression of trkB between chronic spontaneous urticaria and controls and no difference in BDNF serum levels between autologous serum skin test-positive (n=23) and -negative (n=27) patients with chronic spontaneous urticaria. This study shows that BDNF is increased in serum and diseased skin of patients with chronic spontaneous urticaria, suggesting a role for neurotrophins in the pathophysiology of this chronic inflammatory skin disease. Further studies are needed to address the functional role of BDNF on key target effector cells in chronic spontaneous urticaria to establish new therapeutic implications. © 2011 Blackwell Publishing Ltd.

Pneumothorax complicating isolated clavicle fracture

PubMed Central

Hani, Redouane; Ennaciri, Badr; Jeddi, Idriss; El Bardouni, Ahmed; Mahfoud, Mustapha; Berrada, Mohamed Saleh

2015-01-01

Isolated clavicle fractures are among the commonest of traumatic fractures in the emergency department. Complications of isolated clavicle fractures are rare. Pneumothorax has been described as a complication of a fractured clavicle only rarely in English literature. In all the reported cases, the pneumothorax was treated by a thoracostomy and the clavicle fracture was treated conservatively. In our case, the pneumothorax required a chest drain insertion and the clavicle fracture was treated surgically with good result. PMID:26421097

Pneumothorax complicating isolated clavicle fracture.

PubMed

Hani, Redouane; Ennaciri, Badr; Jeddi, Idriss; El Bardouni, Ahmed; Mahfoud, Mustapha; Berrada, Mohamed Saleh

2015-01-01

Isolated clavicle fractures are among the commonest of traumatic fractures in the emergency department. Complications of isolated clavicle fractures are rare. Pneumothorax has been described as a complication of a fractured clavicle only rarely in English literature. In all the reported cases, the pneumothorax was treated by a thoracostomy and the clavicle fracture was treated conservatively. In our case, the pneumothorax required a chest drain insertion and the clavicle fracture was treated surgically with good result.

Computational simulation of progressive fracture in fiber composites

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1986-01-01

Computational methods for simulating and predicting progressive fracture in fiber composite structures are presented. These methods are integrated into a computer code of modular form. The modules include composite mechanics, finite element analysis, and fracture criteria. The code is used to computationally simulate progressive fracture in composite laminates with and without defects. The simulation tracks the fracture progression in terms of modes initiating fracture, damage growth, and imminent global (catastrophic) laminate fracture.

Pore-level influence of micro-fracture parameters on visco-capillary behavior of two-phase displacements in porous media

NASA Astrophysics Data System (ADS)

Rokhforouz, M. R.; Akhlaghi Amiri, H. A.

2018-03-01

In this work, coupled Cahn-Hilliard phase field and Navier-Stokes equations were solved using finite element method to address the effects of micro-fracture and its characterizations on water-oil displacements in a heterogeneous porous medium. Sensitivity studies at a wide range of viscosity ratios (M) and capillary numbers (Ca), and the resultant log Ca-log M stability phase diagram, revealed that in both media, with/without fracture, the three regimes of viscous fingering, capillary fingering and stable displacement similarly occur. However, presence of the fracture caused water channeling phenomenon which resulted in reduction of the number of active fingers and hence the final oil recovery factor. At high Ca (especially in the stable regime, with log Ca ≥ -2.5 and log M ≥ 0), recovery factor for the fractured medium was relatively identical with the non-fractured one. At log M ≥ 0, the fracture was fully swept, but flow instabilities were observed inside the fracture at lower M values, especially for log Ca > -4.6. In the case of the fractured medium at log Ca = -4.6 and log M = 0 (capillary dominant flow), it is observed that the primary breakthrough took place by a finger progressed through the matrix, not those channeled through the fracture. Geometrical properties of the fracture, including length, aperture and orientation, highly affected both displacement profile and efficiency. The fracture length inversely influenced the oil recovery factor. It was observed that there is a critical fracture width (almost half of the medium average pore diameter) at which the recovery factor of the medium during displacement is minimum, compared to the media having thinner and thicker fractures. Minor channeling effect in the media with thinner fracture and larger fracture swept volume as well as high fracture/matrix cross flow in the media with thicker fracture were detected as the main cause of this non-monotonic behavior. In the models with thick fractures (with the thickness higher than the average pore diameter), considerable trapped oil volumes were observed inside the fracture at low M values. The fracture orientation had the most impressive effect on oil recovery compared to the other studied parameters; where the oil recovery factor incremented more than 20% as the fracture rotated 90° from flow direction. Due to the dominant effect of the channeling phenomenon, the change in the medium wettability from slightly oil-wet to slightly water-wet, did not considerably affect the displacement profile in the fractured medium. However, oil recovery factor increased as the medium became more water-wet. The fracture area was fully swept by the injected water in the oil-wet and neutral-wet media. However, flow instabilities were observed inside the fracture of the water-wet medium due to counter-current imbibition between fracture/matrix. Micro-scale mechanisms of pore doublet effect, interface coalesce, snap-off and reverse movements were captured during the studied unstable displacements.

NOTCH signaling in skeletal progenitors is critical for fracture repair

PubMed Central

Wang, Cuicui; Inzana, Jason A.; Mirando, Anthony J.; Liu, Zhaoyang; Shen, Jie; O’Keefe, Regis J.; Awad, Hani A.; Hilton, Matthew J.

2016-01-01

Fracture nonunions develop in 10%–20% of patients with fractures, resulting in prolonged disability. Current data suggest that bone union during fracture repair is achieved via proliferation and differentiation of skeletal progenitors within periosteal and soft tissues surrounding bone, while bone marrow stromal/stem cells (BMSCs) and other skeletal progenitors may also contribute. The NOTCH signaling pathway is a critical maintenance factor for BMSCs during skeletal development, although the precise role for NOTCH and the requisite nature of BMSCs following fracture is unknown. Here, we evaluated whether NOTCH and/or BMSCs are required for fracture repair by performing nonstabilized and stabilized fractures on NOTCH-deficient mice with targeted deletion of RBPjk in skeletal progenitors, maturing osteoblasts, and committed chondrocytes. We determined that removal of NOTCH signaling in BMSCs and subsequent depletion of this population result in fracture nonunion, as the fracture repair process was normal in animals harboring either osteoblast- or chondrocyte-specific deletion of RBPjk. Together, this work provides a genetic model of a fracture nonunion and demonstrates the requirement for NOTCH and BMSCs in fracture repair, irrespective of fracture stability and vascularity. PMID:26950423

Conjugate fracture pairs in the Molina Member of the Wasatch Formation, Piceance basin, Colorado: Implications for fracture origins and hydrocarbon production/exploration

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

Lorenz, J.C.

1997-05-01

The sandstones of the Molina Member of the Wasatch Formation in the Piceance basin of northwestern Colorado contain a suite of fractures that have a conjugate-pair geometry. The fractures are vertical and intersect at an acute angle of between 20 and 40 degrees. Although direct evidence of shear is rare, the fracture surfaces commonly display small steps. The fracture geometries suggest that the maximum compressive stress during fracturing was in the plane of the acute angle of the conjugate fractures: the steps are interpreted as broken-face manifestations of very low angle en echelon fractures, formed within exceptionally narrow zones ofmore » incipient shear. In contrast to the highly anisotropic permeability enhancement created by subparallel vertical extension fractures in the underlying Mesaverde Formation, the conjugate pairs in the Molina sandstones should create a well connected and relatively isotropic mesh of fracture conductivity. Increases in stress magnitudes and anisotropy during production drawdown of reservoir pressures should cause shear offsets along the fractures, initially enhancing permeability.« less

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

A further study on seismic response of a set of parallel rock fractures filled with viscoelastic materials

NASA Astrophysics Data System (ADS)

Wu, W.; Zhu, J. B.; Zhao, J.

2013-02-01

The purpose of this study is to further investigate the seismic response of a set of parallel rock fractures filled with viscoelastic materials, following the work by Zhu et al. Dry quartz sands are used to represent the viscoelastic materials. The split Hopkinson rock bar (SHRB) technique is modified to simulate 1-D P-wave propagation across the sand-filled parallel fractures. At first, the displacement and stress discontinuity model (DSDM) describes the seismic response of a sand-filled single fracture. The modified recursive method (MRM) then predicts the seismic response of the sand-filled parallel fractures. The SHRB tests verify the theoretical predictions by DSDM for the sand-filled single fracture and by MRM for the sand-filled parallel fractures. The filling sands cause stress discontinuity across the fractures and promote displacement discontinuity. The wave transmission coefficient for the sand-filled parallel fractures depends on wave superposition between the fractures, which is similar to the effect of fracture spacing on the wave transmission coefficient for the non-filled parallel fractures.

Bilateral mandibular angle fractures: clinical considerations.

PubMed

Boffano, Paolo; Roccia, Fabio

2010-03-01

The mandibular angle is a frequent site of fracture. It is a weak zone that is more exposed to fractures than other areas of the mandibular bone. The presence of incompletely erupted third molars is associated with a further increased risk of angle fractures. Our objective was to evaluate and discuss the surgical outcomes of a group of patients with bilateral mandibular angle fractures.In our study, patients with bilateral mandibular angle fractures surgically treated from January 1, 2001, to June 30, 2009, at the Division of Maxillofacial Surgery of the University of Turin were retrospectively analyzed. A combined transbuccal and intraoral approach or an intraoral approach only was adopted.Eight patients (7 men and 1 woman) underwent surgery for bilateral mandibular angle fractures. Good to satisfactory reduction of the fractures was obtained with both surgical techniques. Good to fair restored occlusion was observed postoperatively in all patients.Successful treatment of bilateral mandibular angle fractures may be achieved via different techniques. Superficially impacted third molars seem to be associated with an increased risk of angle fractures. Bilateral angle fractures are an ideal model to study the biomechanical pathogenesis of angle fractures.