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Sample records for distal interlocking screw

  1. The best location for proximal locking screw for femur interlocking nailing: A biomechanical study

    PubMed Central

    Karaarslan, Ahmet A; Karakaşli, Ahmet; Aycan, Hakan; Çeçen, Berivan; Yildiz, Didem Venüs; Sesli, Erhan

    2016-01-01

    Background: Proximal locking screw deformation and screw fracture is a frequently seen problem for femur interlocking nailing that affects fracture healing. We realized that there is lack of literature for the right level for the proximal locking screw. We investigated the difference of locking screw bending resistance between the application of screws on different proximal femoral levels. Materials and Methods: We used a total of 80 proximal locking screws for eight groups, 10 screws for each group. Three-point bending tests were performed on four types of screws in two different trochanteric levels (the lesser trochanter and 20 mm proximal). We determined the yield points at three-point bending tests that a permanent deformation started in the locking screws using an axial compression testing machine. Results: The mean yield point value of 5 mm threaded locking screws applied 20 mm proximal of lesser trochanter was 1022 ± 49 (range 986–1057) (mean ± standard deviation, 95% confidence interval). On the other hand, the mean yield point value of the same type of locking screws applied on the lesser trochanteric level was 2089 ± 249 (range 1911–2268). Which means 103% increase of screw resistance between two levels (P = 0.000). In all screw groups, on the lesser trochanter line we determined 98–174% higher than the yield point values of the same type of locking screws in comparison with 20 mm proximal to the lesser trochanter (P = 0.000). Conclusion: According to our findings, there is twice as much difference in locking screw bending resistance between these two application levels. To avoid proximal locking screw deformation, locking screws should be placed in the level of the lesser trochanter in nailing of 1/3 middle and distal femur fractures. PMID:26955183

  2. Fatigue strength of common tibial intramedullary nail distal locking screws

    PubMed Central

    Griffin, Lanny V; Harris, Robert M; Zubak, Joseph J

    2009-01-01

    Background Premature failure of either the nail and/or locking screws with unstable fracture patterns may lead to angulation, shortening, malunion, and IM nail migration. Up to thirty percent of all unreamed nail locking screws can break after initial weight bearing is allowed at 8–10 weeks if union has not occurred. The primary problem this presents is hardware removal during revision surgery. The purposes of our study was to evaluate the relative fatigue resistance of distal locking screws and bolts from representative manufacturers of tibial IM nail systems, and develop a relative risk assessment of screws and materials used. Evaluations included quantitative and qualitative measures of the relative performance of these screws. Methods Fatigue tests were conducted to simulate a comminuted fracture that was treated by IM nailing assuming that all load was carried by the screws. Each screw type was tested ten times in a single screw configuration. One screw type was tested an additional ten times in a two-screw parallel configuration. Fatigue tests were performed using a servohydraulic materials testing system and custom fixturing that simulated screws placed in the distal region of an appropriately sized tibial IM nail. Fatigue loads were estimated based on a seventy-five kilogram individual at full weight bearing. The test duration was one million cycles (roughly one year), or screw fracture, whichever occurred first. Failure analysis of a representative sample of titanium alloy and stainless steel screws included scanning electron microscopy (SEM) and quantitative metallography. Results The average fatigue life of a single screw with a diameter of 4.0 mm was 1200 cycles, which would correspond roughly to half a day of full weight bearing. Single screws with a diameter of 4.5 mm or larger have approximately a 50 percent probability of withstanding a week of weight bearing, whereas a single 5.0 mm diameter screw has greater than 90 percent probability of

  3. Far cortical locking screws in distal femur fractures.

    PubMed

    Adams, John D; Tanner, Stephanie L; Jeray, Kyle J

    2015-03-01

    Distal femur fractures routinely heal by secondary bone healing, which relies on interfragmentary motion. Periarticular locking plates are commonly used for fixation in distal femur fractures but are associated with a high nonunion rate, likely due to the stiffness of the constructs. Far cortical locking (FCL) screws are designed to allow micromotion at the near cortex while maintaining purchase in only the far cortex. Although clinical data are limited, these screws have been shown in biomechanical studies to provide excellent interfragmentary motion, and animal models have shown increased callus formation compared with traditional locking screws. The purpose of this study was to examine the clinical effects that FCL screws have on healing in distal femur fractures treated with locked constructs. In this retrospective case series, 15 patients with a distal femur fracture treated with MotionLoc screws (Zimmer, Warsaw, Indiana) were analyzed. Serial radiographs were evaluated for callus presence and time to union. All fractures were either 33-A3 or 33-C2 according to the AO classification system, and 5 (33%) were open. Bone loss was recorded in 2 patients. There were no nonunions, and average time to union was 24 weeks. There were no implant failures, and all 5 open fractures, including the 2 with bone loss, healed without intervention. There was 1 reoperation due to painful hardware. Although this is a small case series, these results are promising. Far cortical locking screws may provide the answer to the high nonunion rate associated with distal femur fractures treated with traditional locked constructs.

  4. Biomechanical Comparison of Osteoporotic Distal Radius Fractures Fixed by Distal Locking Screws with Different Length

    PubMed Central

    Liu, Xiong; Wu, Wei-dong; Fang, Ya-feng; Zhang, Mei-chao; Huang, Wen-hua

    2014-01-01

    Objectives To evaluate the postoperative stability of osteoporotic distal radius fractures fixed with distal locking screws with different length. Methods A comminuted extra-articular dorsally unstable distal radius fracture, treated with volar locking plate system, was created. The 18 specimens were randomized into 3 groups based on distal locked screws with different length: Group A had unicortical screws with 50% length to the dorsal cortex. Group B had unicortical screws with 75% length to the dorsal cortex. Group C had bicortical screws. Axial compression and bending loads were imposed on the models before and after cycling testing as well as load to clinical and catastrophic failure. Results Minimum change in stiffness was observed before and after fatigue for all groups. The final stiffness to bending forces was statistically similar in all groups, but stiffness to axial compression was statistically significant different: Group A approached significance with respect to groups B and C (P = 0.017, 0.009), whereas stiffness in group B and C was statistically similar (P = 0.93). Load to clinical failure was significantly less for group A (456.54±78.59 N) compared with groups B (580.24±73.85 N) and C (591.07±38.40 N). Load to catastrophic failure was statistically similar between groups, but mean values for Group A were 18% less than means for Group C. Conclusions The volar locking plate system fixed with unicortical locking screws with at least 75% length not only produced early stability for osteoporotic distal radius fractures, but also avoided extensor tendon complications due to dorsal screw protrusion. PMID:25080094

  5. Comparative evaluation of molar distalization therapy using pendulum and distal screw appliances

    PubMed Central

    Cafagna, Alessandra; Fontana, Mattia; Cozzani, Mauro

    2015-01-01

    Objective To compare dentoalveolar and skeletal changes produced by the pendulum appliance (PA) and the distal screw appliance (DS) in Class II patients. Methods Forty-three patients (19 men, 24 women) with Class II malocclusion were retrospectively selected for the study. Twenty-four patients (mean age, 12.2 ± 1.5 years) were treated with the PA, and 19 patients (mean age, 11.3 ± 1.9 years) were treated with the DS. The mean distalization time was 7 months for the PA group and 9 months for the DS group. Lateral cephalograms were obtained at T1, before treatment, and at T2, the end of distalization. A Mann-Whitney U test was used for statistical comparisons of the two groups between T1 and T2. Results PA and DS were equally effective in distalizing maxillary molars (4.7 mm and 4.2 mm, respectively) between T1 and T2; however, the maxillary first molars showed less distal tipping in the DS group than in the PA group (3.2° vs. 9.0°, respectively). Moreover, significant premolar anchorage loss (2.7 mm) and incisor proclination (5.0°) were noted in the PA group, whereas premolar distal movement (1.9 mm) and no significant changes at the incisor (0.1°) were observed in the DS group. No significant sagittal or vertical skeletal changes were detected between the two groups during the distalization phase. Conclusions PA and DS seem to be equally effective in distalizing maxillary molars; however, greater distal molar tipping and premolar anchorage loss can be expected using PA. PMID:26258063

  6. A New Orthodontic Appliance with a Mini Screw for Upper Molar Distalization

    PubMed Central

    2016-01-01

    The aim of this study is to present a new upper molar distalization appliance called Cise distalizer designed as intraoral device supported with orthodontic mini screw for upper permanent molar distalization. The new appliance consists of eight main components. In order to understand the optimum force level, the appliance under static loading is tested by using strain gage measurement techniques. Results show that one of the open coils produces approximately 300 gr distalization force. Cise distalizer can provide totally 600 gr distalization force. This range of force level is enough for distalization of upper first and second molar teeth. PMID:27528796

  7. Standing placement of transphyseal screw in the distal radius in 8 Thoroughbred yearlings

    PubMed Central

    Modesto, Rolf B.; Rodgerson, Dwayne H.; Masciarelli, Amanda E.; Spirito, Michael

    2015-01-01

    This retrospective study describes placement of distal radial transphyseal screws in Thoroughbred yearlings with carpal varus deformities while standing, and identifes short- and long-term complications following the procedure. Data gathered from 2009 to 2013 identified 8 yearlings that met the inclusion criteria. Horses were sedated intravenously and a single 4.5-mm cortical screw was placed in the distal lateral radial physis following application of local anesthetic and surgical preparation of a pre-placed hole. All horses were evaluated weekly after surgery and screw removal was performed standing and under sedation when correction of the angular limb deformity was achieved. The mean time for screw removal was 46 days. No short- or long-term complications were identified. Findings indicate that placing a single transphyseal screw in the lateral aspect of the distal radial physis with the horse standing is a viable option to treat varus angular limb deformity of the carpus in horses. PMID:26028683

  8. Distal tibial physeal bridge: a complication from a tension band plate and screw construct. Report of a case.

    PubMed

    Oda, Jon E; Thacker, Mihir M

    2013-05-01

    We report on a case of a tension band plate and screw construct (Eight Plate) used over the anterior distal tibia in an 9-year-old girl in an attempt to induce recurvatum of the ankle joint to correct a recalcitrant equinus deformity. With growth of the distal tibial physis, the epiphyseal screw was drawn through the physis into the distal tibial metaphysis, resulting in the creation of a transphyseal bony bar. Caution should be exercised when attempting temporary hemiepiphyseodesis using a plate and screw construct in small epiphyses or in an osteopenic bone.

  9. Morphometric analysis of distal interphalangeal joint and implications for arthrodesis with a headless compression screw.

    PubMed

    Braun, Benjamin; Bogle, Andrew; Wiesler, Ethan

    2015-01-01

    Using radiographs of a cross section of patients, measurements of phalanges were done to aid in surgical planning for distal interphalangeal joint (DIPJ) arthrodesis using a headless compression screw. Measurements were performed of the distal and middle phalanx of all fingers and the proximal and distal phalanx of the thumb. Three independent reviewers measured 50 patients. The average measurements (in mm) of anteroposterior (AP) dimensions were as follows: for the thumb P1 and P2: 5.7 and 5.5, lateral 4.2 and 3.5; for the index P2 and P3 AP: 4.2 and 3.3, lateral 2.1 and 1.8; for the long P2 and P3 AP: 4.5 and 3.5, lateral 2.2 and 1.8; for the ring P2 and P3 AP: 4.3 and 3.1, lateral 1.8 and 1.7; and for the small P2 and P3 AP: 3.7 and 2.2, lateral 1.8 and 1.5. Careful surgical planning by measuring the involved digit and knowledge of screw size is paramount to avoid complications from DIPJ arthrodesis with a compression screw.

  10. [Distal tibia peri-implant fracture with an intramedullary nail: a case report].

    PubMed

    Reyes-Cabrera, J M; González-Alconada, R; García-Mota, M D

    2013-01-01

    Peri-implant fractures of the distal tibia after intramedullary nailing are rare. We present a case of a fracture of the distal tibia at the site of the distal interlocking screw. We found two cases reported in the world literature. There are no cases reported in the Spanish literature.

  11. [Validity of modified radiological views to detect screw protrusion at the distal radius. A comparative study with computerized tomography].

    PubMed

    Mora-Pascual, F E; Aguilella-Fernández, L

    2013-01-01

    Volar fixed-angle plates (VFAP) are currently widely used for the treatment of extra-articular distal radius fractures. Using these plates has a high risk of articular and dorsal screw protrusion due to their special configuration. The aim of this study is to assess the validity of the standard X-rays, performed with the help of wedged supports, in order to detect articular and dorsal screw protrusion. A comparison with computed tomography (CT) scan imaging has been made. The outcome of 26 patients with distal radius articular fracture, treated with a VFAP, is reported. Good correlation between modified X-rays and CT scan was observed. A sensitivity of 100% for articular protrusion and 66% for dorsal have been obtained. When detecting screw protrusion at the distal radius, the use of wedged supports to perform special X-rays intraoperatively is an effective tool.

  12. Titanium integration with bone, welding, and screw head destruction complicating hardware removal of the distal radius: report of 2 cases.

    PubMed

    Van Nortwick, Sara S; Yao, Jeffrey; Ladd, Amy L

    2012-07-01

    Increasingly, surgeons treat distal radius fractures with locking plate systems. Recent case reports have focused on technical insertion errors resulting in removal difficulties: poor drilling orientation or cross-threading, destruction of the screw head, and filling of the screw recess with tissue. We report 2 complications of titanium locked plate removal secondary to in vivo reactions including titanium integration with bone and mechanical binding between the titanium screw and plate. We clarify and discuss terminology relevant to implant removal, including cold-welding, galling, fretting, and anodization. Even with optimal technique, in situ reactions can complicate titanium implant removal.

  13. Use of the coventry infant hip screw in the treatment of nonunion of fractures of the distal humerus.

    PubMed

    Simonis, R B; Nuñez, V A; Khaleel, A

    2003-01-01

    Between 1993 and 2000 we treated 14 patients with nonunion of fractures of the distal humerus; 11 had already had previous fixation which had failed. The mean time to surgery was 21 months after injury. All the fractures were very low which made it difficult to obtain a firm hold of the small distal fragment. The problem of fixation was addressed by inserting a Coventry infant hip screw into the humeral condyles. The screw has a thread of wide diameter which gives excellent purchase on the small distal fragment. The condyles can then be compressed on to the humeral shaft using a 4.5 mm narrow tibial dynamic plate. Of these 14 difficult cases of nonunion, 12 progressed to union.

  14. Comparative clinical study of locking screws versus smooth locking pegs in volar plating of distal radius fractures.

    PubMed

    Boretto, J G; Pacher, N; Giunta, D; Gallucci, G L; Alfie, V; De Carli, P

    2014-09-01

    The present study was performed to test the null hypothesis on no difference in stability of fixation after volar plating of intra-articular distal radius fractures (AO C2-C3) with either locking smooth pegs or locking screws in a clinical setting. A retrospective evaluation included adult patients with C2-C3 AO fractures treated with a volar plate with locking smooth pegs or locking screws. Radiographic assessment was performed to evaluate extra- and intra-articular parameters in the early postoperative period and after bone union. Twenty-seven consecutive patients were included. Thirteen cases had fixation with locking screws and 14 had fixation with locking smooth pegs. Both groups had bone fragment displacement after fixation. However, there were no significant differences between the groups either in extra- or intra-articular parameters defined by Kreder et al. (1996). Our study shows that, in a clinical setting, there is no difference in stability fixation between locking screws or smooth locking pegs in C2-C3 distal radius fractures.

  15. Retrograde intramedullary nails with distal screws locked to the nail have higher fatigue strength than locking plates in the treatment of supracondylar femoral fractures: A cadaver-based laboratory investigation.

    PubMed

    Pekmezci, M; McDonald, E; Buckley, J; Kandemir, U

    2014-01-01

    We investigated a new intramedullary locking nail that allows the distal interlocking screws to be locked to the nail. We compared fixation using this new implant with fixation using either a conventional nail or a locking plate in a laboratory simulation of an osteoporotic fracture of the distal femur. A total of 15 human cadaver femora were used to simulate an AO 33-A3 fracture pattern. Paired specimens compared fixation using either a locking or non-locking retrograde nail, and using either a locking retrograde nail or a locking plate. The constructs underwent cyclical loading to simulate single-leg stance up to 125,000 cycles. Axial and torsional stiffness and displacement, cycles to failure and modes of failure were recorded for each specimen. When compared with locking plate constructs, locking nail constructs had significantly longer mean fatigue life (75,800 cycles (SD 33,900) vs 12,800 cycles (SD 6100); p = 0.007) and mean axial stiffness (220 N/mm (SD 80) vs 70 N/mm (SD 18); p = 0.005), but lower mean torsional stiffness (2.5 Nm/° (SD 0.9) vs 5.1 Nm/° (SD 1.5); p = 0.008). In addition, in the nail group the mode of failure was either cut-out of the distal screws or breakage of nails, and in the locking plate group breakage of the plate was always the mode of failure. Locking nail constructs had significantly longer mean fatigue life than non-locking nail constructs (78,900 cycles (SD 25,600) vs 52,400 cycles (SD 22,500); p = 0.04). The new locking retrograde femoral nail showed better stiffness and fatigue life than locking plates, and superior fatigue life to non-locking nails, which may be advantageous in elderly patients.

  16. Radiation exposure to the surgeon during closed interlocking intramedullary nailing

    SciTech Connect

    Levin, P.E.; Schoen, R.W. Jr.; Browner, B.D.

    1987-06-01

    During interlocking intramedullary nailing of twenty-five femoral and five tibial fractures, the primary surgeon wore both a universal film badge on the collar of the lead apron and a thermoluminescent dosimeter ring on the dominant hand to quantify the radiation that he or she received. When distal interlocking was performed, the first ring was removed and a second ring was used so that a separate recording could be made for this portion of the procedure. At the conclusion of the study, all of the recorded doses of radiation were averaged. The average amount of radiation to the head and neck during the entire procedure was 7.0 millirems of deep exposure and 8.0 millirems of shallow exposure. The average dose of radiation to the dominant hand during insertion of the intramedullary nail and the proximal interlocking screw was 13.0 millirems, while the average amount during insertion of the distal interlocking nail was 12.0 millirems. Both of these averages are well within the government guidelines for allowable exposure to radiation during one-quarter (three months) of a year. Precautions that are to be observed during this procedure are recommended.

  17. A comparison of the compressive strength of various distal locking screw options in the treatment of tibia fractures with intramedullary nails.

    PubMed

    Xavier, F; Goldwyn, E; Hayes, W; Carrer, A; Elkhechen, R; Berdichevsky, M; Goldman, A; Urban, W; Saha, S

    2011-01-01

    Treatment of distal metaphyseal tibia fractures is often challenging. Newer tibial intramedullary (IM) nails are designed with a wider variety of distal locking options to offer greater stability in treating these fractures. In this study we attempted to determine the most biomechanically stable number and configuration of distal locking screws when treating distal metaphyseal tibia fractures with IM nails. A transverse osteotomy was created 4 cm from the tibial plafond in identical composite saw bones models (Type 43A fracture) as well as in human cadaveric bones. Each specimen was nailed using a tibial nail (Stryker T2). Distal locking was performed in one of the three configurations: (a) Group I: two screws in the medial lateral (ML) direction; (b) Group II: one ML screw and one screw in the anterior posterior (AP) direction; (c) Group 111: two ML screws and one AP screw. The specimens were then mounted onto a uniaxial material testing machine (Instron) and tested in compression. Our results showed that there was no statistical difference in the load-carrying capacity of Group 1 and Group II. This suggests that the treating surgeon can choose either of these two configurations depending on the wound or other considerations without sacrificing the compressive load-carrying capacity of the IM nail fixation. The load-carrying capacity of the Group III samples with these locking screws was higher than those of Group I & II, although this difference was not statistically significant. This work is being continued to compare the load-carrying capacity of the bone samples with the cortical thickness of bone. We also plan to examine the relationship between the load-carrying capacity of these surgical constructs with the bone mineral density of the metaphysis of these tibial specimens.

  18. Corrective osteotomy of distal radial deformities: a new method of guided locking fixed screw positioning.

    PubMed

    Farshad, M; Hess, F; Nagy, L; Schweizer, A

    2013-01-01

    Corrective osteotomy for distal radial malunion is a valuable but at times technically challenging operation. We have developed a new device to aid in the performance of the operation. We compared clinical use of the new technique with the standard technique. In 11 patients treated with the new technique the volar locking plate needed repositioning only once. With the standard technique in 17 patients the plate was repositioned in nine cases and needed bending in six cases. The new method corrected radial inclination (SD of 3° vs. 9°) and ulnar variance (SD of 0.9 mm vs. 1.4 mm) more predictably than the standard technique but there was no advantage in correction of volar tilt (SD of 6° vs. 4°). In our experience the new device makes corrective osteotomy of the distal radius easier and more reliable.

  19. Biomechanical analyses of static and dynamic fixation techniques of retrograde interlocking femoral nailing using nonlinear finite element methods.

    PubMed

    Shih, Kao-Shang; Hsu, Ching-Chi; Hsu, Tzu-Pin; Hou, Sheng-Mou; Liaw, Chen-Kun

    2014-02-01

    Femoral shaft fractures can be treated using retrograde interlocking nailing systems; however, fracture nonunion still occurs. Dynamic fixation techniques, which remove either the proximal or distal locking screws, have been used to solve the problem of nonunion. In addition, a surgical rule for dynamic fixation techniques has been defined based on past clinical reports. However, the biomechanical performance of the retrograde interlocking nailing systems with either the traditional static fixation technique or the dynamic fixation techniques has not been investigated by using nonlinear numerical modeling. Three-dimensional nonlinear finite element models were developed, and the implant strength, fixation stability, and contact area of the fracture surfaces were evaluated. Three types of femoral shaft fractures (a proximal femoral shaft fracture, a middle femoral shaft fracture, and a distal femoral shaft fracture) fixed by three fixation techniques (insertion of all the locking screws, removal of the proximal locking screws, or removal of the distal locking screws) were analyzed. The results showed that the static fixation technique resulted in sufficient fixation stability and that the dynamic fixation techniques decreased the failure risk of the implant and produced a larger contact area of the fracture surfaces. The outcomes of the current study could assist orthopedic surgeons in comprehending the biomechanical performances of both static and dynamic fixation techniques. In addition, the surgeons could also select a fixation technique based on the specific patient situation using the numerical outcomes of this study.

  20. Imaging Evaluation of the Safe Region for Distal Locking Screw of Proximal Femoral Nail Anti-Rotation in Patients with Proximal Femoral Fracture

    PubMed Central

    Gong, Jinpeng; Liu, Pengcheng; Cai, Ming

    2017-01-01

    Background Proximal femoral nail anti-rotation (PFNA) is a standard femoral intertrochanteric fracture operation. Iatrogenic vascular injury, although uncommon, is a reported complication of PFNA surgery as well as a complication of hip fracture surgery. This study aimed to compare the safety and best use of the distal locking screw in 170 mm PFNA and 240 mm PFNA devices, and to determine the safe region for placement of the distal locking screw in PFNA surgery. Material/Methods A retrospective analysis of 100 patients with 170 mm PFNA and 80 patients with 240 mm PFNA were retrospectively analyzed. Two levels of PFNA distal locking screws were equally divided into three planes: I, II, III, for 170 mm PFNA devices and i, ii, iii for the 240 mm PRNA devices. The medial half of the femur was equally divided into eight regions: A to H. The distance between the outer femur and the superficial, the deep and the perforating femoral arteries (SFAs, DFAs, and PFAs), and angles between the reference line and the connection line between the femur center to each artery were measured. Results SFAs and DFAs but not PFAs were found in risky or hazardous regions, and DFAs were obviously closer to the femur than SFAs and PFAs at the same level. In the region within 10 mm of the femur, no SFAs were found. The short nails (170 mm PFNA-II devices) were the closest to the DFAs region, indicating that the 170 mm PFNA-II nails are most likely to cause special vessel injury. The short nails were relatively more distant from the SFAs, which were located posteriorly to the long nails (240 mm PFNA-II). Conclusions The distal locking screw of the 170 mm PFNA device was more prone to damage the femoral deep artery when the two types of PFNA devices are compared in patients who were candidates for both types of devices. PMID:28178228

  1. [Design of an unconventional interlocked hip arthroplasty system (RIMAG) from Mexican femoral measurement].

    PubMed

    Martínez, Genaro Rico; Domínguez, Víctor H; Muller, José Antonio; Cedillo, Ernesto A Delgado; Roa, Josué Antonio Miranda; Montoya, Roberto C

    2008-01-01

    The need in resolving massive bone losses in hip region caused by tumors, infections, trauma or failed arthroplasties in 17 years of the Bone Tumors Department of the National Rehabilitation Institute, Mexico City, and data obtained from different studies: 1) Biomechanic study of an unconventional hip arthroplasty system, 2) Tridimensional model of a human femur by the finite element method, 3) Biomechanical analysis of a system bone-implant for reconstruction of the proximal third of the femur by the finite element method, 4) Incidence of tumor and pseudotumor bone and soft tissue lesions of the hip, generated the project of designing an unconventional interlocked hip arthroplasty system for femur reconstruction. Two processes were done for adequate manufacturing and dimensioning: Anthropomorphometric study of Mexican femora; 2) Design of an unconventional hip arthroplasty system with the following characteristics: first, the arthroplasty system is constituted by an intramedullar stem, is fixated to femur with interlocking screws, this fixation method was inspired from the design of intramedullar nails of Dr. Fernando Colchero Rosas. The system has a second fixation system in the femur cut region, resolved by a fenestrated support introduced in the cortical wall. Once data was processed, the need for manufacturing 2 models was determined: 1) One for the proximal 11 cm of the femur and 2) other for the 12 distal cm. The height of interlocking screws, 2 models of intracortical proximal support (one fixated and one fixable with an expansible screw), were designed. Diameter, length of the stems, size of spacers and supports were determined for adequate interlocking fixation. We designed the instruments for assembling, impaction and orientation of the arthroplasty system. The system was presented to the Mexican Institute of Industrial Property, at March 15, 1996 and the patent was conceded April 19, 2007 (#245717).

  2. Use of the radial groove view intra-operatively to prevent damage to the extensor pollicis longus tendon by protruding screws during volar plating of a distal radial fracture.

    PubMed

    Lee, S K; Bae, K W; Choy, W S

    2013-10-01

    The aims of this study were to assess the efficacy of a newly designed radiological technique (the radial groove view) for the detection of protrusion of screws in the groove for the extensor pollicis longus tendon (EPL) during plating of distal radial fractures. We also aimed to determine the optimum position of the forearm to obtain this view. We initially analysed the anatomy of the EPL groove by performing three-dimensional CT on 51 normal forearms. The mean horizontal angle of the groove was 17.8° (14° to 23°). We found that the ideal position of the fluoroscopic beam to obtain this view was 20° in the horizontal plane and 5° in the sagittal plane. We then intra-operatively assessed the use of the radial groove view for detecting protrusion of screws in the EPL groove in 93 fractures that were treated by volar plating. A total of 13 protruding screws were detected. They were changed to shorter screws and these patients underwent CT scans of the wrist immediately post-operatively. There remained one screw that was protruding. These findings suggest that the use of the radial groove view intra-operatively is a good method of assessing the possible protrusion of screws into the groove of EPL when plating a fracture of the distal radius.

  3. Recurrent GCT of Distal Femur Treated with Resection Arthrodesis with Non-Vascularized Bilateral Fibular Graft and A Custom-Made Interlock Nail

    PubMed Central

    Sanesh, Tuteja; Sachin, Kale; Prasad, Chaudhari; Sanjay, B Dhar

    2016-01-01

    Introduction: Giant Cell Tumors commonly occur around the knee joint in the age group of 20-30 years. They are treated with intra-lesional curettage or local resection and limb reconstruction. Management of large bone defects after resection is a challenge and is of ten complicated with non-union of grafts, infection and delayed weight bearing. Case Presentation: A 37-year-old male presented with an aggressive recurrent giant cell tumor of the distal femur. He was and was diagnosed with a GCT of the left distal femur 2 years ago for which he was treated with an intralesional curettage and Poly methylmetacrylate implantation. A resection arthrodesis using a bilateral non-vascularised intramedullary fibular graft and a custom made intramedullary nail was performed. The follow-up radiographs showed union at graft-host junction and hypertrophy of the grafted fibula at 2 years post surgery. Conclusion: Non-vascularised fibular graft is an effective alternative for resection arthrodesis with the advantages of a simpler and shorter surgical procedure and without the needs for a microsurgical setup. PMID:28116258

  4. Tibiotarsal fracture repair in a bald eagle (Haliaeetus leucocephalus) using an interlocking nail.

    PubMed

    Hollamby, Simon; Dejardin, Loic M; Sikarskie, James G; Haeger, Jennifer

    2004-03-01

    A 14-yr-old, 5.13-kg bald eagle (Haliaeetus leucocephalus) was hit by a car and presented to the Michigan State University Small Animal Clinic with an open, grade II, transverse, midshaft, Winquist-Hansen type-II-comminuted left tibiotarsal fracture. The fracture was reduced and fixation established with a 4.7-mm-diameter, 112-mm-long, four-hole veterinary intramedullary interlocking nail maintained in position by single 2-mm transcortical screws placed in the main proximal and distal fragments. The bird was weight bearing on the bandaged limb 48 hr postoperatively. Radiographs obtained 4 wk postoperatively revealed bridging callus over three of four cortices. The bird was released after 5 mo of rehabilitation.

  5. The Retrograde Tibial Nail: presentation and biomechanical evaluation of a new concept in the treatment of distal tibia fractures.

    PubMed

    Kuhn, Sebastian; Appelmann, Philipp; Pairon, Philip; Mehler, Dorothea; Rommens, Pol M

    2014-01-01

    Displaced distal tibia fractures require stable fixation while minimizing secondary damage to the soft tissues by the surgical approach and implants. Antegrade intramedullary nailing has become an alternative to plate osteosynthesis for the treatment of distal metaphyseal fractures over the past two decades. While retrograde intramedullary nailing is a standard procedure in other long bone fractures, only few attempts have been made on retrograde nailing of tibial fractures. The main reasons are difficulties of finding an ideal entry portal and the lack of an ideal implant for retrograde insertion. The Retrograde Tibial Nail (RTN) is a prototype intramedullary implant developed by our group. The implant offers double proximal and triple distal interlocking with an end cap leading to an angle-stable screw-nail construct of the most distal interlocking screw. Its design meets the requirements of a minimally invasive surgical approach, with a stable fracture fixation by multiple locking options. The 8mm diameter curved nail, with a length of 120 mm, is introduced through an entry portal at the medial malleolus. We see possible indications for the RTN in far distal tibial shaft fractures, distal extraarticular metaphyseal tibial fractures and in distal tibia fractures with simple extension into the ankle joint when the nail is combined lag screw fixation. A biomechanical comparison of the current RTN prototype against antegrade nailing (Expert Tibial Nail, Synthes(®), ETN) was performed. Both implants were fixed with double proximal and triple distal interlocking. Seven biomechanical composite tibiae were treated with either osteosynthesis techniques. A 10mm defect osteotomy 40 mm proximal to the joint line served as an AO 43-A3 type distal tibial fracture model. The stiffness of the implant-bone constructs was measured under low and high extra-axial compression (350 and 600 N) and under torsional load (8 Nm). Results show a comparable stability during axial loading

  6. Laser interlock system

    SciTech Connect

    Woodruff, Steven D; Mcintyre, Dustin L

    2015-01-13

    A method and device for providing a laser interlock having a first optical source, a first beam splitter, a second optical source, a detector, an interlock control system, and a means for producing dangerous optical energy. The first beam splitter is optically connected to the first optical source, the first detector and the second optical source. The detector is connected to the interlock control system. The interlock control system is connected to the means for producing dangerous optical energy and configured to terminate its optical energy production upon the detection of optical energy at the detector from the second optical source below a predetermined detector threshold. The second optical source produces an optical energy in response to optical energy from the first optical source. The optical energy from the second optical source has a different wavelength, polarization, modulation or combination thereof from the optical energy of the first optical source.

  7. Biomechanical effects of angular stable locking in intramedullary nails for the fixation of distal tibia fractures.

    PubMed

    Augat, Peter; Hoegel, Florian; Stephan, Daniel; Hoffmann, Stephanie; Buehren, Volker

    2016-11-01

    Treatment of distal tibia shaft fractures using intramedullary nailing requires stable fixation of the distal fragment to prevent malunion. Angular stable locking for intramedullary nails pledge to provide increased mechanical stability. This study tested the hypothesis that intramedullary nails with angular stable interlocking screws would have increased construct stiffness, reduced fracture gap movement and enhanced fatigue failure compared to nails with conventional locking having the same diameter. Biomechanical experiments were performed on 24 human cadaveric tibiae which obtained a distal fracture and were fixed by three different techniques: conventional locking with 8- and 10-mm-diameter nails and angular stable locking with 8-mm nails. Stiffness of the implant-bone construct and movement of the fragments were tested under axial loading and torsion. The constructs were tested to failure under cyclic fatigue loading. Analysis of variance and Kaplan-Meier survival analysis were used for statistical assessment. Axial stiffness of the 10-mm nail was about 50% larger compared to both 8-mm nail constructs independent of the type of locking mode (p < 0.01). No differences were found in axial performance between angular stable and conventional locking neither under static nor under cyclic testing conditions (p > 0.5). Angular stability significantly decreased the clearance under torsional load by more than 50% compared to both conventionally locked constructs (p = 0.03). However, due to the larger nail diameter, the total interfragmentary motion was still smallest for the 10-mm nail construct (p < 0.01). Although the 10-mm nail constructs survived slightly longer, differences between groups were minor and not statistically significant (p = 0.4). Our hypothesis that angular stable interlocking of intramedullary nails would improve mechanical performance of distal tibia fracture fixation was not confirmed in a physiologically realistic loading

  8. Interlocked systems in nanomedicine.

    PubMed

    Ornelas-Megiatto, Catia; Becher, Tiago B; Megiatto, Jackson D

    2015-01-01

    The concept of Nanomedicine emerged along with the new millennium, and it is expected to provide solutions to some of modern medicine's unsolved problems. Nanomedicine offers new hopes in several critical areas such as cancer treatment, viral and bacterial infections, medical imaging, tissue regeneration, and theranostics. To explore all these applications, a wide variety of nanomaterials have been developed which include liposomes, dendrimers, nanohydrogels and polymeric, metallic and inorganic nanoparticles. Recently, interlocked systems, namely rotaxanes and catenanes, have been incorporated into some of these chemical platforms in an attempt to improve their performance. This review focus on the nanomedicine applications of nanomaterials containing interlocked structures. The introduction gives an overview on the significance of interdisciplinary science in the progress of the nanomedicine field, and it explains the evolution of interlocked molecules until their application in nanomedicine. The following sections are organized by the type of interlocked structure, and it comprises details of the in vitro and/or in vivo experiments involving each material: rotaxanes as imaging agents, rotaxanes as cytotoxic agents, rotaxanes as peptide transporters, mechanized silica nanoparticles as stimuli responsive drug delivery systems, and polyrotaxanes as drug and gene delivery systems.

  9. FUEL ELEMENT INTERLOCKING ARRANGEMENT

    DOEpatents

    Fortescue, P.; Nicoll, D.

    1963-01-01

    This patent relates to a system for mutually interlocking a multiplicity of elongated, parallel, coextensive, upright reactor fuel elements so as to render a laterally selfsupporting bundle, while admitting of concurrent, selective, vertical withdrawal of a sizeable number of elements without any of the remaining elements toppling, Each element is provided with a generally rectangular end cap. When a rank of caps is aligned in square contact, each free edge centrally defines an outwardly profecting dovetail, and extremitally cooperates with its adjacent cap by defining a juxtaposed half of a dovetail- receptive mortise. Successive ranks are staggered to afford mating of their dovetails and mortises. (AEC)

  10. Split spline screw

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1993-01-01

    A split spline screw type payload fastener assembly, including three identical male and female type split spline sections, is discussed. The male spline sections are formed on the head of a male type spline driver. Each of the split male type spline sections has an outwardly projecting load baring segment including a convex upper surface which is adapted to engage a complementary concave surface of a female spline receptor in the form of a hollow bolt head. Additionally, the male spline section also includes a horizontal spline releasing segment and a spline tightening segment below each load bearing segment. The spline tightening segment consists of a vertical web of constant thickness. The web has at least one flat vertical wall surface which is designed to contact a generally flat vertically extending wall surface tab of the bolt head. Mutual interlocking and unlocking of the male and female splines results upon clockwise and counter clockwise turning of the driver element.

  11. 49 CFR 236.820 - Switch, interlocked.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Switch, interlocked. 236.820 Section 236.820 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Switch, interlocked. A switch within the interlocking limits the control of which is interlocked...

  12. 49 CFR 236.820 - Switch, interlocked.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Switch, interlocked. 236.820 Section 236.820 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Switch, interlocked. A switch within the interlocking limits the control of which is interlocked...

  13. 49 CFR 236.820 - Switch, interlocked.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Switch, interlocked. 236.820 Section 236.820 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Switch, interlocked. A switch within the interlocking limits the control of which is interlocked...

  14. 49 CFR 236.820 - Switch, interlocked.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Switch, interlocked. 236.820 Section 236.820 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Switch, interlocked. A switch within the interlocking limits the control of which is interlocked...

  15. 49 CFR 236.820 - Switch, interlocked.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Switch, interlocked. 236.820 Section 236.820 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Switch, interlocked. A switch within the interlocking limits the control of which is interlocked...

  16. Treatment of distal intraarticular tibial fractures: A biomechanical evaluation of intramedullary nailing vs. angle-stable plate osteosynthesis.

    PubMed

    Kuhn, Sebastian; Greenfield, Julia; Arand, Charlotte; Jarmolaew, Andrey; Appelmann, Philipp; Mehler, Dorothea; Rommens, Pol M

    2015-10-01

    In factures of the distal tibia with simple articular extension, the optimal surgical treatment remains debatable. In clinical practice, minimally invasive plate osteosynthesis and intramedullary nailing are both routinely performed. Comparative biomechanical studies of different types of osteosynthesis of intraarticular distal tibial fractures are missing due to the lack of an established model. The goal of this study was first to establish a biomechanical model and second to investigate, which are the biomechanical advantages of angle-stable plate osteosynthesis and intramedullary nailing of distal intraarticular tibial fractures. Seven 4(th) generation biomechanical composite tibiae featuring an AO 43-C2 type fracture were implanted with either osteosynthesis technique. After primary lag screw fixation, 4-hole Medial Distal Tibial Plate (MDTP) with triple proximal and quadruple distal screws or intramedullary nailing with double proximal and triple 4.0mm distal interlocking were implanted. The stiffness of the implant-bone constructs and interfragmentary movement were measured under non-destructive axial compression (350 and 600 N) and torsion (1.5 and 3Nm). Destructive axial compression testing was conducted with a maximal load of up to 1,200 N. No overall superior biomechanical results can be proclaimed for either implant type. Intramedullary nailing displays statistically superior results for axial loading in comparison to the MDTP. Torsional loading resulted in non-statistically significant differences for the two-implant types with higher stability in the MDTP group. From a biomechanical view, the load sharing intramedullary nail might be more forgiving and allow for earlier weight bearing in patients with limited compliance.

  17. 49 CFR 236.751 - Interlocking, manual.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Interlocking, manual. An arrangement of signals and signal appliances operated from an interlocking machine and so interconnected by means of mechanical and/or electric locking that their movements must...

  18. 49 CFR 236.751 - Interlocking, manual.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Interlocking, manual. An arrangement of signals and signal appliances operated from an interlocking machine and so interconnected by means of mechanical and/or electric locking that their movements must...

  19. 49 CFR 236.753 - Limits, interlocking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Limits, interlocking. 236.753 Section 236.753 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Limits, interlocking. The tracks between the opposing home signals of an interlocking....

  20. 2. ENVIRONMENT, FROM SOUTHEAST, SHOWING B&P INTERLOCKING TOWER, AUXILIARY INTERLOCKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. ENVIRONMENT, FROM SOUTHEAST, SHOWING B&P INTERLOCKING TOWER, AUXILIARY INTERLOCKING BUILDING, AND POWER SUBSTATION - Baltimore & Potomac Interlocking Tower, Adjacent to AMTRAK railroad tracks in block bounded by Howard Street, Jones Falls Expressway, Maryland Avenue & Falls Road, Baltimore, Independent City, MD

  1. Usefulness of absorbable screws in the Sauvé-Kapandji procedure for rheumatoid wrist reconstruction.

    PubMed

    Nakamura, K; Oda, H; Tanaka, S; Kuga, Y; Yamamoto, M; Nishikawa, T; Juji, T; Shimizu, M

    2002-06-01

    Abstract  In the Sauvé-Kapandji (S-K) procedure for rheumatoid wrist reconstruction, the distal end of the ulna is fixed to the radius with screws. Recently, absorbable screws have increasingly been used instead of metal ones. However, the clinical usefulness of absorbable screws in S-K procedures for rheumatoid patients is still unknown. The purpose of this article is to evaluate the effect of absorbable screws in this procedure by comparing their clinical results with those of metal screws. Poly-l-lactic acid (PLLA) absorbable screws were used in 23 wrists, and metal screws were used in 20 wrists. We evaluated the presence of general or local reactions to PLLA, the stability of the ulnar head, the time to bone union, changes in the shape of the distal ulna, and the presence of bone resorption around the screws. There were no complications with the use of PLLA screws, and their fixation stability was adequate to form sufficient bone union. In five cases in the metal screw group, bone resorption around the screws occurred between 1 and 2 years after surgery. Bone resorption around the PLLA screws was not observed. We conclude that absorbable screws may be more useful than metal screws in the S-K procedure for rheumatoid wrist reconstruction.

  2. DISTAL MYOPATHIES

    PubMed Central

    Dimachkie, Mazen M.; Barohn, Richard J.

    2014-01-01

    Over a century ago, Gowers described two young patients in whom distal muscles weakness involved the hand, foot, sternocleidomastoid, and facial muscles in the other case the shoulder and distal leg musculature. Soon after, , similar distal myopathy cases were reported whereby the absence of sensory symptoms and of pathologic changes in the peripheral nerves and spinal cord at postmortem examination allowed differentiation from Charcot-Marie-Tooth disease. In 1951, Welander described autosomal dominant (AD) distal arm myopathy in a large Scandanavian cohort. Since then the number of well-characterized distal myopathies has continued to grow such that the distal myopathies have formed a clinically and genetically heterogeneous group of disorders. Affected kindred commonly manifest weakness that is limited to foot and toe muscles even in advanced stages of the disease, with variable mild proximal leg, distal arm, neck and laryngeal muscle involvement in selected individuals. An interesting consequence of the molecular characterization of the distal myopathies has been the recognition that mutation in a single gene can lead to more than one clinical disorder. For example, Myoshi myopathy (MM) and limb girdle muscular dystrophy (LGMD) type 2B are allelic disorders due to defects in the gene that encodes dysferlin. The six well described distal myopathy syndromes are shown in Table 1. Table 2 lists advances in our understanding of the myofibrillar myopathy group and Table 3 includes more recently delineated and less common distal myopathies. In the same manner, the first section of this review pertains to the more traditional six distal myopathies followed by discussion of the myofibrillar myopathies. In the third section, we review other clinically and genetically distinctive distal myopathy syndromes usually based upon single or smaller family cohorts. The fourth section considers other neuromuscular disorders that are important to recognize as they display prominent

  3. 49 CFR 236.772 - Machine, interlocking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Machine, interlocking. 236.772 Section 236.772 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Machine, interlocking. An assemblage of manually operated levers or other devices for the control...

  4. 49 CFR 236.772 - Machine, interlocking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Machine, interlocking. 236.772 Section 236.772 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Machine, interlocking. An assemblage of manually operated levers or other devices for the control...

  5. 49 CFR 236.772 - Machine, interlocking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Machine, interlocking. 236.772 Section 236.772 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Machine, interlocking. An assemblage of manually operated levers or other devices for the control...

  6. 76 FR 42767 - Management Officials Interlocks

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-19

    ... Office of Thrift Supervision Management Officials Interlocks AGENCY: Office of Thrift Supervision (OTS... Management and Budget (OMB) for review, as required by the Paperwork Reduction Act. Today, OTS is soliciting...: Management Officials Interlocks. OMB Number: 1550-0051. Form Number: N/A. Description: OTS uses the...

  7. Arthroscopic Arthrodesis of the Distal Tibiofibular Syndesmosis.

    PubMed

    Lui, Tun Hing

    2015-01-01

    Chronic syndesmosis disruption can occur if an acute lesion is missed or inadequately managed. This can result in significant functional deficit and development of post-traumatic ankle arthritis. Anatomic reduction of the syndesmosis and maintenance of the reduction by syndesmotic screw fixation alone, ligamentous reconstruction, or fusion of the syndesmosis are recommended. A technique of arthroscopic distal tibiofibular syndesmosis arthrodesis is described.

  8. 12 CFR 303.249 - Management official interlocks.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Management official interlocks. 303.249 Section... PROCEDURES Other Filings § 303.249 Management official interlocks. (a) Scope. This section contains the... interlock pursuant to the Depository Institutions Management Interlocks Act (12 U.S.C. 3207), section 13...

  9. Radiation-free drill guidance in interlocking of intramedullary nails.

    PubMed

    Diotte, Benoit; Fallavollita, Pascal; Wang, Lejing; Weidert, Simon; Thaller, Peter-Helmut; Euler, Ekkehard; Navab, Nassir

    2012-01-01

    Intramedullary nailing is a technically demanding procedure which involves an excessive amount of x-ray acquisitions; one study lists as many as 48 to successfully complete the procedure. In this work, a novel low cost radiation-free drilling guide is designed to assist surgeons in completing the distal locking procedure without any x-ray acquisitions. Using an augmented reality fluoroscope that coregisters optical and x-ray images, we exploit solely the optical images to detect the drilling guide in order to estimate the tip position in real-time in x-ray. We tested over 200 random drill guide poses showing a mean tip-estimation error of 1.72 +/- 0.7mm which is significantly robust and accurate for the interlocking. In a preclinical study on dry bone phantom, three expert surgeons successfully completed the interlocking 56 out of 60 trials with no x-ray acquisition for guidance and an average time of 2 min.

  10. [The use of blade plate and dynamic screw plate osteosynthesis].

    PubMed

    Oestern, H J; Gänsslen, A

    2010-02-01

    Osteosynthesis in fracture treatment and in some reconstructive procedures with blade plates or dynamic screw systems was the standard procedure for several decades. In this review, the current options and concepts using blade plate osteosynthesis, stabilization of proximal and distal femur fractures and reconstructive procedures with the dynamic hip screw or the dynamic condylar blade are discussed. On the basis of a literature review, the present indications, results and region-specific complications are reported and discussed.Blade plates are used mainly in the context of reconstructive procedures, as well as in the treatment of pseudoarthroses. The Pauwel procedure in femoral neck non-unions is one of the best known indications. In contrast, the dynamic hip screw is the gold standard for stabilization of femoral neck and most pertrochanteric fractures, whereas the dynamic condylar screw is still an alternative to internal fixators for proximal and distal femoral fracture fixations.

  11. Interlocking egg-crate type grid assembly

    DOEpatents

    Kast, Steven J.

    1987-01-01

    Disclosed is an interlocking egg-crate hexagonal grid for supporting a nuclear fuel pin in a hexagonal array. The grid is formed from strips bent at an angle of about 120.degree. at each vertex. Over some faces of each hexagonal cell the strips are coplanar but are arranged, by stacking and interlocking, to avoid any double thickness of metal in that plane. Springs and dimples are formed in the faces of each cell to hold the fuel pin substantially centered.

  12. Interlocking egg-crate type grid assembly

    DOEpatents

    Kast, S.J.

    1985-03-15

    Disclosed is an interlocking egg-crate hexagonal grid for supporting a nuclear fuel pin in a hexagonal array. The grid is formed from strips bent at an angle of about 120/sup 0/ at each vertex. Over some faces of each hexagonal cell the strips are coplanar but are arranged, by stacking interlocking, to avoid any double thickness of metal in that plane. Springs and dimples are formed in the faces of each cell to hold the fuel pin substantially centered.

  13. PBS machine interlocks using EWMA

    NASA Astrophysics Data System (ADS)

    Clasie, Benjamin M.; Kooy, Hanne M.; Flanz, Jacob B.

    2016-01-01

    Delivery of pencil beam scanning (PBS) requires the on-line measurement of several beam parameters. If the measurement is outside of specified tolerances and a binary threshold algorithm is used, the beam will be paused. Given instrumentation and statistical noise such a system can lead to many pauses which could increase the treatment time. Statistical quality control methods are typically used on manufacturing lines to monitor a process and give early detection of a gradual problem and stop the process if a deviation is statistically significant. These methods can be used to develop a more intuitive algorithm for (PBS) delivery systems that is robust and safe and leads to decreased treatment times. The Exponentially Weighted Moving Average (EWMA) control scheme monitors deviations in beam properties which are averaged over a specified number of measurements with greater weight applied to the more recent ones. Simulation of an EWMA-style algorithm safely detected shifts in random and systematic delivery errors without false alarms. Binary and EWMA methods can be combined for improved reliability without sacrificing patient safety. In the EWMA method, the mean of a beam property can be related to systematic uncertainties and the standard deviation can be related to random uncertainties. This method allows one to have separate interlock levels for each type of uncertainty and to detect systematic trends.

  14. PBS machine interlocks using EWMA.

    PubMed

    Clasie, Benjamin M; Kooy, Hanne M; Flanz, Jacob B

    2016-01-07

    Delivery of pencil beam scanning (PBS) requires the on-line measurement of several beam parameters. If the measurement is outside of specified tolerances and a binary threshold algorithm is used, the beam will be paused. Given instrumentation and statistical noise such a system can lead to many pauses which could increase the treatment time. Statistical quality control methods are typically used on manufacturing lines to monitor a process and give early detection of a gradual problem and stop the process if a deviation is statistically significant. These methods can be used to develop a more intuitive algorithm for (PBS) delivery systems that is robust and safe and leads to decreased treatment times. The Exponentially Weighted Moving Average (EWMA) control scheme monitors deviations in beam properties which are averaged over a specified number of measurements with greater weight applied to the more recent ones. Simulation of an EWMA-style algorithm safely detected shifts in random and systematic delivery errors without false alarms. Binary and EWMA methods can be combined for improved reliability without sacrificing patient safety. In the EWMA method, the mean of a beam property can be related to systematic uncertainties and the standard deviation can be related to random uncertainties. This method allows one to have separate interlock levels for each type of uncertainty and to detect systematic trends.

  15. 3. General view showing north elevation of Shell Interlocking Tower ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. General view showing north elevation of Shell Interlocking Tower and electric relay station. - New York, New Haven, & Hartford Railroad, Shell Interlocking Tower, New Haven Milepost 16, approximately 100 feel east of New Rochelle Junction, New Rochelle, Westchester County, NY

  16. Mechanically interlocked DNA nanostructures for functional devices.

    PubMed

    Jester, Stefan-S; Famulok, Michael

    2014-06-17

    CONSPECTUS: Self-assembled functional DNA oligonucleotide based architectures represent highly promising candidates for the creation of nanoscale devices. The field of DNA nanotechnology has emerged to a high level of maturity and currently constitutes one of the most dynamic, creative, and exciting modern research areas. The transformation from structural DNA nanotechnology to functional DNA architectures is already taking place with tremendous pace. Particularly the advent of DNA origami technology has propelled DNA nanotechnology forward. DNA origami provided a versatile method for precisely aligning structural and functional DNA modules in two and three dimensions, thereby serving as a means for constructing scaffolds and chassis required for the precise orchestration of multiple functional DNA architectures. Key modules of these will contain interlocked nanomechanical components made of DNA. The mechanical interlocking allows for performing highly specific and controlled motion, by reducing the dimensionality of diffusion-controlled processes without restrictions in motional flexibility. Examples for nanoscale interlocked DNA architectures illustrate how elementary functional units of future nanomachines can be designed and realized, and show what role interlocked DNA architectures may play in this endeavor. Functional supramolecular systems, in general, and nanomachinery, in particular, self-organize into architectures that reflect different levels of complexity with respect to their function, their arrangement in the second and third dimension, their suitability for different purposes, and their functional interplay. Toward this goal, DNA nanotechnology and especially the DNA origami technology provide opportunities for nanomechanics, nanorobotics, and nanomachines. In this Account, we address approaches that apply to the construction of interlocked DNA nanostructures, drawing largely form our own contributions to interlocked architectures based on double

  17. Nonmagnetic rigid and flexible outer sheath with pneumatic interlocking mechanism for minimally invasive surgical approach.

    PubMed

    Yamashita, Hiromasa; Zuo, Siyang; Masamune, Ken; Liao, Hongen; Dohi, Takeyoshi

    2009-01-01

    We developed a nonmagnetic rigid and flexible outer sheath with pneumatic interlocking mechanism using flexible toothed links and a wire-driven bending distal end. The outer sheath can be switched between rigid and flexible modes easily depending on surgical scenes, and the angle of its distal end can be controlled by three nylon wires. All components of flexible parts are made of MRI-compatible nonmagnetic plastics. We manufactured the device with 300-mm long, 16-mm outer diameter, 7-mm inner diameter and 90-mm bending distal end. Holding power of the device in rigid mode was maximum 3.6 N, which was sufficient for surgical tasks in body cavity. In vivo experiment using a swine, our device performed smooth insertion of a flexible endoscope and a biopsy forceps into reverse side of the liver, intestines and spleen with a curved path. In conclusion, our device shows availability of secure approach of surgical instruments into deep cavity.

  18. 21 CFR 876.4590 - Interlocking urethral sound.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Interlocking urethral sound. 876.4590 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4590 Interlocking urethral sound. (a) Identification. An interlocking urethral sound is a device that consists of two metal...

  19. 21 CFR 876.4590 - Interlocking urethral sound.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Interlocking urethral sound. 876.4590 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4590 Interlocking urethral sound. (a) Identification. An interlocking urethral sound is a device that consists of two metal...

  20. 21 CFR 876.4590 - Interlocking urethral sound.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Interlocking urethral sound. 876.4590 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4590 Interlocking urethral sound. (a) Identification. An interlocking urethral sound is a device that consists of two metal...

  1. 21 CFR 876.4590 - Interlocking urethral sound.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Interlocking urethral sound. 876.4590 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4590 Interlocking urethral sound. (a) Identification. An interlocking urethral sound is a device that consists of two metal...

  2. 21 CFR 876.4590 - Interlocking urethral sound.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Interlocking urethral sound. 876.4590 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4590 Interlocking urethral sound. (a) Identification. An interlocking urethral sound is a device that consists of two metal...

  3. Interlocked molecules: Moving into another dimension

    NASA Astrophysics Data System (ADS)

    Fournel-Marotte, Karine; Coutrot, Frédéric

    2016-12-01

    Molecular daisy-chain structures are typically made up of two interlocked components and can exhibit muscle-like contraction and extension in one dimension. Zinc-based multicomponent systems that can operate in two and three dimensions have now been designed and synthesized.

  4. 49 CFR 236.772 - Machine, interlocking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Machine, interlocking. 236.772 Section 236.772 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... signals, switches or other units. Cross Reference: Magnet, track, see § 236.744....

  5. 49 CFR 236.772 - Machine, interlocking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Machine, interlocking. 236.772 Section 236.772 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... signals, switches or other units. Cross Reference: Magnet, track, see § 236.744....

  6. 49 CFR 236.750 - Interlocking, automatic.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.750 Interlocking, automatic. An arrangement of signals, with or without other signal appliances, which functions... manually, and which are so interconnected by means of electric circuits that their movements must...

  7. FERMILAB CRYOMODULE TEST STAND RF INTERLOCK SYSTEM

    SciTech Connect

    Petersen, Troy; Diamond, J. S.; McDowell, D.; Nicklaus, D.; Prieto, P. S.; Semenov, A.

    2016-10-12

    An interlock system has been designed for the Fermilab Cryo-module Test Stand (CMTS), a test bed for the cryo- modules to be used in the upcoming Linac Coherent Light Source 2 (LCLS-II) project at SLAC. The interlock system features 8 independent subsystems, one per superconducting RF cavity and solid state amplifier (SSA) pair. Each system monitors several devices to detect fault conditions such as arcing in the waveguides or quenching of the SRF system. Additionally each system can detect fault conditions by monitoring the RF power seen at the cavity coupler through a directional coupler. In the event of a fault condition, each system is capable of removing RF signal to the amplifier (via a fast RF switch) as well as turning off the SSA. Additionally, each input signal is available for re- mote viewing and recording via a Fermilab designed digitizer board and MVME 5500 processor.

  8. Thermal static bending of deployable interlocked booms

    NASA Technical Reports Server (NTRS)

    Staugaitis, C. L.; Predmore, R. E.

    1973-01-01

    Metal ribbons processed with a heat-forming treatment are enabled to form tubelike structures when deployed from a roll. Deployable booms of this have been utilized for gravity-gradient stabilization on the RAE, ATS, and Nimbus D satellites. An experimental thermal-mechanics test apparatus was developed to measure the thermal static bending and twist of booms up to 3 meters long. The apparatus was calibrated by using the correlation between calculated and observed thermal bending of a seamless tube. Thermal static bending values of 16 interlocked deployable booms were observed to be within a factor of 2.5 of the values calculated from seamless-tube theory. Out-of-Sun-plane thermal bending was caused by complex heat transfer across the interlocked seam. Significant thermal static twisting was not observed.

  9. Interlocking Intramedullary Nails in Fracture Treatment.

    PubMed

    Ouyang, Xiao; Wang, Jing Rong; Hong, Shi Dong; Xin, Feng; Wang, Lin; Yang, Xiao Wei; Wang, Jian

    2015-09-01

    The aim of this study is to evaluate interlocking intramedullary nails in the treatment of fractures. We retrospectively reviewed 68 adult patients (for a total of 95 fractures) with isolated long-bone fractures who were treated with interlocking intramedullary nails between January 2010 and January 2012. The patients were followed for 18 months to observe the healing of the fracture, time, and the occurrence of complications in the shoulder, knee, and hip joint functions. After about a follow-up period of 26.2 months (range 18-39 months), all cases obtained bony union. The mean time to fracture union was 5.2 months. Cases of knees and hip joint functions of the femoral or tibial fracture and shoulder functions of the humeral fractures were observed. The interlocking intramedullary nails may be considered as an alternative method for isolated diaphyseal fractures of the extremities. The advantages of this method include small operative scars, reliable fixations, better fracture healings, and fewer complications.

  10. The effect of screw insertion torque on tendons fixed with spiked washers.

    PubMed

    Beynnon, B D; Meriam, C M; Ryder, S H; Fleming, B C; Johnson, R J

    1998-01-01

    The long-term success of a hamstring tendon graft depends not only on the type of device that is used for fixation but also on the mechanical interlocking of the soft tissue between the fixation device and bone. The purpose of this study was to evaluate the effect of screw insertion torque on the structural properties of soft tissue fixed to bone with a spiked metal washer. Two bovine tendons, one similar in size to a human semitendinosus tendon and the other similar in size to a human gracilis tendon, were secured to a bovine femur using a figure-of-8 technique with screws and metal spiked washers. A single load to failure was applied at 25 mm/sec. A significant positive linear correlation was observed between fixation screw insertion torque magnitude and the ultimate failure load value. An increase in the fixation screw insertion torque produced an increase in the ultimate failure load value. Similarly, there was a significant positive linear correlation between fixation screw insertion torque magnitude and the average maximum linear load value. No relationship was detected between screw insertion torque magnitude and the linear stiffness values of the tendon-fixation construct, indicating that a reproducible model was used. This study demonstrates that screw insertion torque is an important variable that controls the initial strength of soft tissue fixation to bone.

  11. Ball Screw Actuator Including a Compliant Ball Screw Stop

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Hanlon, Casey (Inventor)

    2017-01-01

    An actuator includes a ball nut, a ball screw, and a ball screw stop. The ball nut is adapted to receive an input torque and in response rotates and supplies a drive force. The ball screw extends through the ball nut and has a first end and a second end. The ball screw receives the drive force from the ball nut and in response selectively translates between a retract position and a extend position. The ball screw stop is mounted on the ball screw proximate the first end to translate therewith. The ball screw stop engages the ball nut when the ball screw is in the extend position, translates, with compliance, a predetermined distance toward the first end upon engaging the ball nut, and prevents further rotation of the ball screw upon translating the predetermined distance.

  12. Ball Screw Actuator Including a Compliant Ball Screw Stop

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Hanlon, Casey (Inventor)

    2015-01-01

    An actuator includes a ball nut, a ball screw, and a ball screw stop. The ball nut is adapted to receive an input torque and in response rotates and supplies a drive force. The ball screw extends through the ball nut and has a first end and a second end. The ball screw receives the drive force from the ball nut and in response selectively translates between a retract position and a extend position. The ball screw stop is mounted on the ball screw proximate the first end to translate therewith. The ball screw stop engages the ball nut when the ball screw is in the extend position, translates, with compliance, a predetermined distance toward the first end upon engaging the ball nut, and prevents further rotation of the ball screw upon translating the predetermined distance.

  13. Distal splenorenal shunt

    MedlinePlus

    ... shunt; Cirrhosis - distal splenorenal; Liver failure - distal splenorenal; Portal vein pressure - distal splenorenal shunt ... vein from your spleen is removed from the portal vein. The vein is then attached to the ...

  14. Operative treatment of distal radius fractures.

    PubMed

    Vasenius, J

    2008-01-01

    The incidence of distal radius fractures is increasing together with the average age of population. Intra-articular incongruity is the most probable cause of unsatisfactory outcome of distal radius fractures in younger and more active patients. Thus, the main goal in the treatment of distal radius fractures should be restoration of articular congruence. A computed tomography (CT) is recommended to help surgeon in preoperative planning in the treatment of comminuted intra-articular fractures. New implants have been designed to provide stable enough fixation for early mobilisation after surgery and to lower rather high complication rates related to conventional fixation methods such as external fixation and dorsal plating. The most common complications related to volar fixed angle plating such as flexor and extensor tendon problems, median nerve neuropathy, and screw diplacement into the radiocarpal joint are surgeon related and are avoidable with proper education. More randomized prospective studies are needed to prove superiority of any fixation method to another.

  15. Beam-limiting and radiation-limiting interlocks

    SciTech Connect

    Macek, R.J.

    1996-04-01

    This paper reviews several aspects of beam-limiting and radiation- limiting interlocks used for personnel protection at high-intensity accelerators. It is based heavily on the experience at the Los Alamos Neutron Science Center (LANSCE) where instrumentation-based protection is used extensively. Topics include the need for ``active`` protection systems, system requirements, design criteria, and means of achieving and assessing acceptable reliability. The experience with several specific devices (ion chamber-based beam loss interlock, beam current limiter interlock, and neutron radiation interlock) designed and/or deployed to these requirements and criteria is evaluated.

  16. Minimizing the complications of intramedullary nailing for distal third tibial shaft and metaphyseal fractures

    PubMed Central

    Yaligod, Vishwanath; Rudrappa, Girish H.; Nagendra, Srinivas; Shivanna, Umesh M.

    2013-01-01

    Background The complications of intramedullary nailing of distal third tibial shaft and metaphyseal fractures have a direct impact on ankle and hind foot function. Methods We retrospectively evaluated 28 patients. Unreamed nail was negotiated across the well reduced fracture till subchondral bone and fixed with 2 to 3 distal locking screws in different planes. Results Fracture union rate was 85%. Three out of 28 patients had malalignment. Mean ankle, hindfoot functional score was 85. Conclusion Complications can be minimized by impacting the unreamed nail till the subchondral bone while maintaining the fracture well reduced and by using multiple distal locking screws in different planes. PMID:24719527

  17. 20. VIEW OF NEWER 7LEVER INTERLOCKING MACHINE IN FOREGROUND, NEXT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. VIEW OF NEWER 7-LEVER INTERLOCKING MACHINE IN FOREGROUND, NEXT TO ORIGINAL INTERLOCKING MACHINE, THIRD FLOOR - South Station Tower No. 1 & Interlocking System, Dewey Square, Boston, Suffolk County, MA

  18. Helical screw viscometer

    DOEpatents

    Aubert, J.H.; Chapman, R.N.; Kraynik, A.M.

    1983-06-30

    A helical screw viscometer for the measurement of the viscosity of Newtonian and non-Newtonian fluids comprising an elongated cylindrical container closed by end caps defining a circular cylindrical cavity within the container, a cylindrical rotor member having a helical screw or ribbon flight carried by the outer periphery thereof rotatably carried within the cavity whereby the fluid to be measured is confined in the cavity filling the space between the rotor and the container wall. The rotor member is supported by axle members journaled in the end caps, one axle extending through one end cap and connectable to a drive source. A pair of longitudinally spaced ports are provided through the wall of the container in communication with the cavity and a differential pressure meter is connected between the ports for measuring the pressure drop caused by the rotation of the helical screw rotor acting on the confined fluid for computing viscosity.

  19. 12 CFR 26.4 - Interlocking relationships permitted by statute.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... MANAGEMENT OFFICIAL INTERLOCKS § 26.4 Interlocking relationships permitted by statute. The prohibitions of... served by a management official of another credit union; (d) A depository organization that does not do... in any part of the United States; (ii) The service would lead to substantial conflicts of interest...

  20. 12 CFR 196.4 - Interlocking relationships permitted by statute.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... MANAGEMENT OFFICIAL INTERLOCKS § 196.4 Interlocking relationships permitted by statute. The prohibitions of... served by a management official of another credit union; (d) A depository organization that does not do... in any part of the United States; (ii) The service would lead to substantial conflicts of interest...

  1. 12 CFR 348.4 - Interlocking relationships permitted by statute.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... OF GENERAL POLICY MANAGEMENT OFFICIAL INTERLOCKS § 348.4 Interlocking relationships permitted by...); (c) A credit union being served by a management official of another credit union; (d) A depository....S.C. 1823(k)) with resulting dual service by a management official that would otherwise...

  2. 21. Historic view looking northeast from tracks of Shell Interlocking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. Historic view looking northeast from tracks of Shell Interlocking Tower after construction, 1909. Photographic copy of photograph published in Railway Age Gazette, February 4, 1910. - New York, New Haven, & Hartford Railroad, Shell Interlocking Tower, New Haven Milepost 16, approximately 100 feel east of New Rochelle Junction, New Rochelle, Westchester County, NY

  3. 11. General view of Shell Interlocking Tower, west and south ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. General view of Shell Interlocking Tower, west and south facades, view from railroad grade, looking northeast. - New York, New Haven, & Hartford Railroad, Shell Interlocking Tower, New Haven Milepost 16, approximately 100 feel east of New Rochelle Junction, New Rochelle, Westchester County, NY

  4. Administrative Reinstatement Interlock Programs: Florida, a 10-Year Study

    PubMed Central

    Voas, Robert B.; Tippetts, A. Scott; Grosz, Milton

    2013-01-01

    Background Interlocks reduce driving-under-the-influence (DUI) recidivism by 64%, but offenders resist installing them, preferring to risk driving while their driver’s licenses are revoked. One method of motivating offenders to install an interlock is require it for reinstatement of their driver’s license. This report updates an earlier evaluation of the administrative reinstatement interlock program (ARIP) procedure implemented in Florida in 2002. Method Driver records and interlock program records covering 120,000 DUI offenders were followed over 10 years. The flow through the sanction system—conviction, reinstatement, interlock program, and postinterlock period—is described. Logistical regression was used to identify the characteristics of offenders who installed interlocks, and survival analysis was used to evaluate the recidivism of offenders in the various stages in the ARIP. Results At any given time, approximately one third of the convicted offenders were serving their license-revocation periods. Half of the offenders who completed their revocation periods remain unqualified for reinstatement because they do not fulfill other requirements. ARIP offenders who do qualify for reinstatement and install interlocks have lower recidivism rates while the devices are on their vehicles. Conclusions After 10 years, Florida’s ARIP is a mature system that succeeds in forcing all offenders in the program who qualify for reinstatement to install an interlock for at least 6 months. However, half of all offenders who complete their mandatory revocation period are either unable to, or choose not to, qualify for reinstatement. PMID:23442206

  5. 6. Detail of northeast corner of Shell Interlocking Tower, showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Detail of northeast corner of Shell Interlocking Tower, showing ornamental east concrete beltcourse and tower shield with bronze numerals. - New York, New Haven, & Hartford Railroad, Shell Interlocking Tower, New Haven Milepost 16, approximately 100 feel east of New Rochelle Junction, New Rochelle, Westchester County, NY

  6. 5. General oblique view of Shell Interlocking Tower to southwest, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. General oblique view of Shell Interlocking Tower to southwest, showing east and north facades. Relay station is on far left. - New York, New Haven, & Hartford Railroad, Shell Interlocking Tower, New Haven Milepost 16, approximately 100 feel east of New Rochelle Junction, New Rochelle, Westchester County, NY

  7. Fabrication and Evaluation of a Noncompliant Molar Distalizing Appliance: Bonded Molar Distalizer

    PubMed Central

    Sodagar, A.; Ahmad Akhoundi, M. S.; Rafighii, A.; Arab, S.

    2011-01-01

    Objective Attempts to treat class II malocclusions without extraction in non-compliant patients have led to utilization of intraoral molar distalizing appliances. The purpose of this study was to investigate dental and skeletal effects of Bonded Molar Distalizer (BMD) which is a simple molar distalizing appliance. Materials and Methods Sixteen patients (12 girls, four boys) with bilateral half-cusp class II molar relationship, erupted permanent second molars and normal or vertical growth pattern were selected for bilateral distalization of maxillary molars via BMD. The screws were activated every other day, alternately. Lateral cephalograms and study models were obtained before treatment and after 11 weeks activation of the appliance. Results Significant amounts of molar distalization, molar distal tipping and anchorage loss were observed. The mean maxillary first molar distal movement was 1.22±0.936 mm with a distal tipping of 2.97±3.74 degrees in 11 weeks. The rate of distal movement was 0.48 mm per month. Reciprocal mesial movement of the first premolars was 2.26±1.12 mm with a mesial tipping of 4.25±3.12 degrees. Maxillary incisors moved 3.55±1.46 mm and tipped 9.87±5.03 degrees mesially. Lower anterior face height (LAFH) decreased 1.28±1.36 mm. Conclusion BMD is appropriate for distalizing maxillary molars, especially in patients with critical LAFH, although significant amounts of anchorage loss occur using this appliance. PMID:22457837

  8. Power connect safety and connection interlock

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E. (Inventor)

    1992-01-01

    A power connect safety and connection interlock system is shown for use with inverters and other DC loads (16) which include capacitor filter banks (14) at their DC inputs. A safety circuit (20) operates a spring (26) biased, solenoid (22) driven mechanical connection interference (24) which prevents mating and therefore electrical connection between the power contactor halves (11, 13) of the main power contacts (12) until the capacitor bank is safely precharged through auxiliary contacts (18). When the DC load (16) is shut down, the capacitor bank (14) is automatically discharged through a discharging power resistor (66) by a MOSFET transistor (60) through a discharging power resistor (66) only when both the main power contacts and auxiliary contacts are disconnected.

  9. Enhancing the Use of Vehicle Alcohol Interlocks With Emerging Technology

    PubMed Central

    Voas, Robert B.

    2014-01-01

    Among the earliest applications of health technologies to a safety program was the development of blood alcohol content (BAC) tests for use in impaired-driving enforcement. This led to the development of miniature, highly accurate devices that officers could carry in their pockets. A natural extension of this technology was the vehicle alcohol interlock, which is used to reduce recidivism among drivers convicted of driving under the influence (DUI) by requiring them to install the devices (which will not allow someone with a positive BAC to drive) on their vehicles. While on the vehicle, interlocks have been shown to reduce recidivism by two-thirds. Use of these devices has been growing at the rate of 10 to 15 percent a year, and there currently are more than 300,000 units in use. This expansion in the application of interlocks has benefited from the integration of other emerging technologies into interlock systems. Such technologies include data systems that record both driver actions and vehicle responses, miniature cameras and face recognition to identify the user, Wi-Fi systems to provide rapid reporting on offender performance and any attempt to circumvent the device, GPS tracking of the vehicle, and more rapid means for monitoring the integrity of the interlock system. This article describes how these health technologies are being applied in interlock programs and the outlook for new technologies and new court sanctioning programs that may influence the growth in the use of interlocks in the future. PMID:26259002

  10. Enhancing the Use of Vehicle Alcohol Interlocks With Emerging Technology.

    PubMed

    Voas, Robert B

    2014-01-01

    Among the earliest applications of health technologies to a safety program was the development of blood alcohol content (BAC) tests for use in impaired-driving enforcement. This led to the development of miniature, highly accurate devices that officers could carry in their pockets. A natural extension of this technology was the vehicle alcohol interlock, which is used to reduce recidivism among drivers convicted of driving under the influence (DUI) by requiring them to install the devices (which will not allow someone with a positive BAC to drive) on their vehicles. While on the vehicle, interlocks have been shown to reduce recidivism by two-thirds. Use of these devices has been growing at the rate of 10 to 15 percent a year, and there currently are more than 300,000 units in use. This expansion in the application of interlocks has benefited from the integration of other emerging technologies into interlock systems. Such technologies include data systems that record both driver actions and vehicle responses, miniature cameras and face recognition to identify the user, Wi-Fi systems to provide rapid reporting on offender performance and any attempt to circumvent the device, GPS tracking of the vehicle, and more rapid means for monitoring the integrity of the interlock system. This article describes how these health technologies are being applied in interlock programs and the outlook for new technologies and new court sanctioning programs that may influence the growth in the use of interlocks in the future.

  11. An evaluation of Nova Scotia's alcohol ignition interlock program.

    PubMed

    Vanlaar, Ward G M; Mainegra Hing, Marisela; Robertson, Robyn D

    2017-03-01

    Alcohol ignition interlock programs for offenders aim to reduce recidivism among convicted drink drivers. This study presents an evaluation of Nova Scotia's interlock program implemented in 2008 in order to assess its effectiveness to reduce impaired driving and to help identify areas for improvement. Data used include conviction and crash records of individual participants; provincial monthly counts of alcohol-related charges, convictions and fatal and serious crashes; and interlock logged events. Methods used include descriptive statistics, survival analysis, time series and logistic regression analysis. With respect to specific deterrence (i.e., preventing recidivism) there was a 90% reduction in recidivism among voluntary participants since participation in the interlock program and a 79% reduction after these participants exited from the program. With respect to general deterrence (i.e., referring to a preventative effect on the entire population of drivers in Nova Scotia) there were temporary decreases in the numbers of alcohol-related charges (13.32%) and convictions (9.93%) and a small significant decrease in the number of fatal and serious injury alcohol-related crashes, following the implementation of the program. The evidence suggests the interlock program was better at preventing harm due to alcohol-impaired driving than the alternative of not using the interlock program. Recommendations were formulated supporting the continuation of the interlock program in Nova Scotia.

  12. Distal Femur Locking Plate: The Answer to All Distal Femoral Fractures

    PubMed Central

    Garg, Sudhir Kumar; Gupta, Parmanand; Jangira, Vivek; Singh, Jagdeep; Rana, Sudhir

    2016-01-01

    Introduction Good results have been published by researchers with distal femur nail, dynamic condylar screw and even addition of a medial plate to a distal femur locking plate for treating distal femur fractures. By this study, we explore the capability of a distal femur locking plate to counter distal femur fractures of extra- articular, partial or intra- articular nature. Positive results have been published by various groups from all over the world. Aim To study the functional and radiological outcome of distal femoral fractures in skeletally mature patients treated by open reduction and internal fixation with distal femur locking plate. Materials and Methods This was a prospective study conducted from January 2012 to March 2014 at the Government Medical College and Hospital (GMCH) with a 2 year follow-up. Twenty five skeletally mature patients with post-traumatic distal femur fractures were included. Patients with open grade 3B and 3C distal femur fractures, according to the Gustilo- Anderson classification and pathological distal femur fractures were excluded from the study. Patients with any fracture other than the distal femur in the ipsilateral limb were excluded from the study. Follow-up at 3 months, 6 months, 1 year and 2 years was carried out and evaluation was done according to the Neer scoring system. The statistical data analysis was carried out using SPSS version 20 (IBM, Chicago, USA). The p-value <0.05 was considered significant. Results Following all principles of fracture reduction, union was achieved in all patients with mean time to radiological union being 19 weeks. The mean Range of Motion (ROM) was 109 degrees with 20 patients having a Neer score graded as excellent to satisfactory. Our study had nine cases which required additional surgeries. Out of these, all nine cases required bone grafting, three also required antibiotic cement bead insertion initially. Three patients developed complications in the form of infection (two cases) and mal

  13. NUT SCREW MECHANISMS

    DOEpatents

    Glass, J.A.F.

    1958-07-01

    A reactor control mechanism is described wherein the control is achieved by the partial or total withdrawal of the fissile material which is in the form of a fuel rod. The fuel rod is designed to be raised and lowered from the reactor core area by means of two concentric ball nut and screw assemblies that may telescope one within the other. These screw mechanisms are connected through a magnetic clutch to a speed reduction gear and an accurately controllable prime motive source. With the clutch energized, the fuel rod may be moved into the reactor core area, and fine adjustments may be made through the reduction gearing. However, in the event of a power failure or an emergency signal, the magnetic clutch will become deenergized, and the fuel rod will drop out of the core area by the force of gravity, thus shutting down the operation of the reactor.

  14. A capillary Archimedes' screw

    NASA Astrophysics Data System (ADS)

    Darbois Texier, Baptiste; Dorbolo, Stephane

    2014-11-01

    As used by Egyptians for irrigation and reported by Archimedes, a screw turning inside a hollow pipe can pull out a fluid againt gravity. At a centimetric scale, an analagous system can be found with a drop pending on a rotating spiral which is tilted toward the horizontal. The ascent of the drop to the top of the spiral is considered and a theoretical model based on geometrical considerations is proposed. The climb of the drop is limited by the fluid deposition on the screw at high capillary number and by a centrifugation phenomenon. We find out the range of fluid proprities and spiral characteristics for which an ascending motion of the drop is possible. Finally we discuss the efficiency of such system to extract a fluid from a bath at a centrimetric scale.

  15. Drill Free Screws: a new form of osteosynthesis screw.

    PubMed

    Heidemann, W; Gerlach, K L; Gröbel, K H; Köllner, H G

    1998-06-01

    Although the application of self-tapping and non self-tapping screws is virtually universal in cranio-maxillofacial surgery, the inevitable, time consuming procedure of drilling a pilot hole has some potential disadvantages, such as damage to nerves, tooth roots or tooth germs, thermal necrosis of the bone and drill bit breakage. Drill Free Screws (DFS) are a recently developed type of osteosynthesis screws, having a tip like a cork screw and specially formed cutting flutes which enable insertion of the screws without drilling. DFS 1.5 and 2 mm were inserted into discs of wood, polyvinylchloride (PVC) and porcine mandibular bone of varying thicknesses between 2 and 4 mm. The values of insertion torque and maximum torque were recorded using an electric torque tester. Thereafter, the screws were inserted with a fixed torque and uniaxial pull out tests were performed. In comparison with this, the same procedure was performed using 1.5 and 2 mm self-tapping titanium screws. Ten trials for each screw-material-combination were conducted to determine insertion torque, maximum torque and pull out analysis. The results showed that the holding power of DFS lay between 70 and 104% of the holding power of self-tapping titanium screws; only in PVC was the difference more than 15%.

  16. Synthesis of interlocked molecules by olefin metathesis

    NASA Astrophysics Data System (ADS)

    Clark, Paul Gregory

    A large body of work in the Grubbs group has focused on the development of functional-group tolerant ruthenium alkylidene catalysts that perform a number of olefin metathesis reactions. These catalysts have seen application in a wide range of fields, including classic total synthesis as well as polymer and materials chemistry. One particular family of compounds, interlocked molecules, has benefitted greatly from these advances in catalyst stability and activity. This thesis describes several elusive and challenging interlocked architectures whose syntheses have been realized through the utilization of different types of ruthenium-catalyzed olefin metathesis reactions. Ring-closing olefin metathesis has enabled the synthesis of a [c2]daisy-chain dimer with the ammonium binding site near the cap of the dimer. A deprotonated DCD possessing such a structural attribute will more forcefully seek to restore coordinating interactions upon reprotonation, enhancing its utility as a synthetic molecular actuator. Dimer functionalization facilitated incorporation into linear polymers, with a 48% size increase of an unbound, extended analogue of the polymer demonstrating slippage of the dimer units. Ongoing work is directed at further materials studies, in particular, exploring the synthesis of macroscopic networks containing the DCD units and analyzing the correlation between molecular-scale extension-contraction manipulations and resulting macro-scale changes. A "clipping" approach to a polycatenated cyclic polymer, a structure that resembles a molecular "charm bracelet", has been described. The use of ring-opening metathesis polymerization of a carbamate monomer in the presence of a chain transfer agent allowed for the synthesis of a linear polymer that was subsequently functionalized and cyclized to the corresponding cyclic analogue. This cyclic polymer was characterized through a variety of techniques, and subjected to further functionalization reactions, affording a cyclic

  17. Foreign body reaction after PLC reconstruction caused by a broken PLLA screw.

    PubMed

    Kim, Tae-Kwon; Jeong, Tae-Wan; Lee, Dae-Hee

    2014-12-01

    Foreign body reactions may occur in patients who receive bioabsorbable implants during orthopedic surgery for fractures and ligament repair. The authors describe a 34-year-old man who presented with a palpable tender mass on the lateral aspect of the left knee of 1 month's duration. He underwent posterior cruciate ligament and posterolateral corner reconstruction 3 years earlier. Physical examination showed a 1×1-cm soft, nontender mass without localized warmth on the lateral epicondyle of the distal femur. Magnetic resonance imaging showed a broken screw fragment surrounded by a cyst-like mass. Under general anesthesia, the surgeon excised the screw fragment and the fibrotic mass, enclosing it in the subcutaneous tissue at the lateral epicondyle, the site at which a poly-L-lactic acid bioabsorbable screw had been inserted to fix the graft for posterolateral corner reconstruction. Histologic evaluation showed a foreign body reaction to the degraded screw particles. To the authors' knowledge, this report is the first description of a patient presenting with a delayed foreign body reaction to a broken poly-L-lactic acid bioabsorbable screw at the lateral femoral epicondyle after posterolateral corner reconstruction. Because delayed foreign body reactions can occur at any site of poly-L-lactic acid bioabsorbable screw insertion, care should be taken to avoid screw protrusion during ligament reconstruction because it can lead to screw breakage and delayed foreign body reaction.

  18. INTERIOR VIEW OF WEST BANK RAILROAD CONTROL TOWER SHOWING INTERLOCKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF WEST BANK RAILROAD CONTROL TOWER SHOWING INTERLOCKING SWITCHING LEVER CONTROL PANEL. - Huey P. Long Bridge, Spanning Mississippi River approximately midway between nine & twelve mile points upstream from & west of New Orleans, Jefferson, Jefferson Parish, LA

  19. 9. VIEW, LOOKING NORTHWEST, SHOWING PIPING FOR INTERLOCKING AND SIGNALLING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. VIEW, LOOKING NORTHWEST, SHOWING PIPING FOR INTERLOCKING AND SIGNALLING SYSTEM - New York, New Haven & Hartford Railroad, Niantic Bridge, Spanning Niantic River between East Lyme & Waterford, Old Lyme, New London County, CT

  20. 34. Boston switch interlocking tower. Central Falls, Providence Co., RI. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. Boston switch interlocking tower. Central Falls, Providence Co., RI. Sec. 4116, mp 190.40. - Northeast Railroad Corridor, Amtrak route between CT & MA state lines, Providence, Providence County, RI

  1. DETAIL OF STANDARD INTERLOCKING MACHINE OPERATING LEVERS. LOCKING MECHANISM IS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF STANDARD INTERLOCKING MACHINE OPERATING LEVERS. LOCKING MECHANISM IS BELOW FLOOR. BOXES BEHIND SOME LEVERS HOUSE ELECTRICAL CONTACTS FOR SIGNALS. - Baltimore & Ohio Railroad, Z Tower, State Route 46, Keyser, Mineral County, WV

  2. B & P Junction Substation & Interlocking Tower. Baltimore, Baltimore ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    B & P Junction Substation & Interlocking Tower. Baltimore, Baltimore City, MD. Sec. 1201, MP 95.85. - Northeast Railroad Corridor, Amtrak route between District of Columbia/Maryland state line & Maryland/Delaware state line, Baltimore, Independent City, MD

  3. Refining the maintenance techniques for Interlocking Concrete Paver GIs - abstract

    EPA Science Inventory

    Surface clogging adversely affects the performance of Interlocking Concrete Pavements (ICP) by reducing their ability to infiltrate stormwater runoff. Determining the correct methods for remedial maintenances is crucial to recovering and maintaining efficient ICP performance. T...

  4. Refining the maintenance techniques for Interlocking Concrete Paver GIs

    EPA Science Inventory

    Surface clogging adversely affects the performance of Interlocking Concrete Pavements (ICP) by reducing their ability to infiltrate stormwater runoff. The clogging rate is a function of pavement type, traffic loading, surrounding physical environment and maintenance treatments. ...

  5. Low noise lead screw positioner

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor)

    1986-01-01

    A very precise and low noise lead screw positioner, for positioning a retroreflector in an interferometer is described. A gas source supplies inert pressurized gas, that flows through narrow holes into the clearance space between a nut and the lead screw. The pressurized gas keeps the nut out of contact with the screw. The gas flows axially along the clearance space, into the environment. The small amount of inert gas flowing into the environment minimizes pollution. By allowing such flow into the environment, no seals are required between the end of the nut and the screw.

  6. Biomechanics and biology of plate fixation of distal radius fractures.

    PubMed

    Freeland, Alan E; Luber, Kurre T

    2005-08-01

    The fracture management principles of anatomic or near anatomic reduction, fracture stabilization, minimal operative trauma, and early joint motion are paramount in man-aging unstable distal radial fractures. The operative approach and plate selection should correlate with the fracture configuration. Plates have the advantages of providing secure fixation throughout the entire healing process without protruding wires or pins and allowing early and intensive forearm, wrist, and digital exercises. Disadvantages include additional operative trauma, including fragment devascularization; some additional risk of wrist stiffness; occasional tendon rupture; and at times, the need for plate removal. New developments in plate and screw design and operative strategies, fragment specific fixation, and plate strength have improved results with plate fixation. Fixed angle blades and locking screws and pegs enhance overall plate stability, support the articular surface of the distal radius, and are effective in fractures occurring in osteopenic bone.

  7. Do CT scans aid assessment of distal tibial physeal fractures?

    PubMed

    Cutler, L; Molloy, A; Dhukuram, V; Bass, A

    2004-03-01

    Distal tibial physeal fractures are the second most common growth plate injury and the most common cause of growth arrest and deformity. This study assesses the accuracy of pre-operative planning for placement of the screws in these fractures using either standard radiographs or CT scans. We studied 62 consecutive physeal fractures over a period of four years. An outline of a single cut of the CT scan was used for each patient. An ideal position for the screw was determined as being perpendicular to and at the midpoint of the fracture. The difference in entry point and direction of the screw between the ideal and the observers' assessments were compared using the paired Student's t-test. There was a statistically significant improvement (p < 0.0001) in the accuracy of the point of insertion and the direction of the screw on the pre-operative plan when CT scans were used rather than plain radiographs. We would, therefore, recommend that CT scans are routinely used in the pre-operative assessment and treatment of distal tibial physeal fractures.

  8. Breath alcohol ignition interlock devices: controlling the recidivist.

    PubMed

    Raub, Richard A; Lucke, Roy E; Wark, Richard I

    2003-01-01

    This study compares the recidivism rates of two groups of Illinois drivers who had their driver's licenses revoked for alcohol-impaired driving and who received restricted driving permits. Drivers in both groups had more than two driving under the influence (DUI) actions against their record within 5 years or were classed as level III alcohol dependents. Drivers in one group were required to install breath alcohol ignition interlock devices in their vehicles and drivers in the other group were not. The research found that drivers with the interlock were one-fifth as likely to be arrested for DUI during the 1 year the device was installed as the comparison group, which did not have the device. However, once the ignition interlock was removed, drivers in this group rapidly returned to DUI arrest rates similar to those in the comparison group. These findings echo previous literature. Additionally, the study showed that this voluntary program in Illinois reached only 16% of the drivers who met the requirements for installing the interlock device. Finally, this study found that individuals who were removed from the interlock program and returned to revoked status continued to drive. Within 3 years, approximately 50% of this latter group were involved in a crash or were arrested for DUI or with an invalid driver's license. Conclusions drawn from the study suggest that the breath alcohol ignition interlock device is effective in preventing continued driving while impaired. However, the large-scale effectiveness of the device is limited since most of the drivers eligible for the device do not have it installed. To have a significant impact, the interlock device must represent a better alternative to drivers whose licenses were suspended or revoked because of alcohol arrests compared to remaining on revoked status without having the device installed. Finally the research suggests that, given the rapid return to predevice recidivism, the devices should remain installed until

  9. Breath alcohol ignition interlock devices: controlling the recidivist.

    PubMed

    Raub, Richard A; Lucke, Roy E; Wark, Richard I

    2003-09-01

    This study compares the recidivism rates of two groups of Illinois drivers who had their driver's licenses revoked for alcohol-impaired driving and who received restricted driving permits. Drivers in both groups had more than two driving under the influence (DUI) actions against their record within 5 years or were classed as level III alcohol dependents. Drivers in one group were required to install breath alcohol ignition interlock devices in their vehicles and drivers in the other group were not. The research found that drivers with the interlock were one-fifth as likely to be arrested for DUI during the 1 year the device was installed as the comparison group, which did not have the device. However, once the ignition interlock was removed, drivers in this group rapidly returned to DUI arrest rates similar to those in the comparison group. These findings echo previous literature. Additionally, the study showed that this voluntary program in Illinois reached only 16% of the drivers who met the requirements for installing the interlock device. Finally, this study found that individuals who were removed from the interlock program and returned to revoked status continued to drive. Within 3 years, approximately 50% of this latter group were involved in a crash or were arrested for DUI or with an invalid driver's license. Conclusions drawn from the study suggest that the breath alcohol ignition interlock device is effective in preventing continued driving while impaired. However, the large-scale effectiveness of the device is limited since most of the drivers eligible for the device do not have it installed. To have a significant impact, the interlock device must represent a better alternative to drivers whose licenses were suspended or revoked because of alcohol arrests compared to remaining on revoked status without having the device installed. Finally the research suggests that, given the rapid return to predevice recidivism, the devices should remain installed until

  10. Growth modulation with a medial malleolar screw for ankle valgus deformity

    PubMed Central

    Rupprecht, Martin; Spiro, Alexander S; Breyer, Sandra; Vettorazzi, Eik; Ridderbusch, Karsten; Stücker, Ralf

    2015-01-01

    Background and purpose Growth modulation with a medial malleolar screw is used to correct ankle valgus deformity in children with a wide spectrum of underlying etiologies. It is unclear whether the etiology of the deformity affects the angular correction rate with this procedure. Patients and methods 79 children (20 girls) with ankle valgus deformity had growth modulation by a medial malleolar screw (125 ankles). To be included, patients had to have undergone screw removal at the time of skeletal maturity or deformity correction, or a minimum follow-up of 18 months, and consistent radiographs preoperatively and at the time of screw removal and/or follow-up. The patients were assigned to 1 of 7 groups according to their underlying diagnoses. The lateral distal tibial angle (LDTA) was analyzed preoperatively, at screw removal, and at follow-up. Results Mean age at operation was 11.7 (7.4–16.5) years. The average lateral distal tibial angle normalized from 80° (67–85) preoperatively to 89° (73–97) at screw removal. The screws were removed after an average time of 18 (6–46) months, according to an average rate of correction of 0.65° (0.1–2.2) per month. No significant differences in the correction rate per month were found between the groups (p = 0.3). Interpretation Growth modulation with a medial malleolar screw is effective for the treatment of ankle valgus deformity in patients with a wide spectrum of underlying diagnoses. The individual etiology of the ankle valgus does not appear to affect the correction rate after growth modulation. Thus, the optimal timing of growth modulation mainly depends on the remaining individual growth and on the extent of the deformity. PMID:25909385

  11. Adaptive mechanical properties of topologically interlocking material systems

    NASA Astrophysics Data System (ADS)

    Khandelwal, S.; Siegmund, T.; Cipra, R. J.; Bolton, J. S.

    2015-04-01

    Topologically interlocked material systems are two-dimensional granular crystals created as ordered and adhesion-less assemblies of unit elements of the shape of platonic solids. The assembly resists transverse forces due to the interlocking geometric arrangement of the unit elements. Topologically interlocked material systems yet require an external constraint to provide resistance under the action of external load. Past work considered fixed and passive constraints only. The objective of the present study is to consider active and adaptive external constraints with the goal to achieve variable stiffness and energy absorption characteristics of the topologically interlocked material system through an active control of the in-plane constraint conditions. Experiments and corresponding model analysis are used to demonstrate control of system stiffness over a wide range, including negative stiffness, and energy absorption characteristics. The adaptive characteristics of the topologically interlocked material system are shown to solve conflicting requirements of simultaneously providing energy absorption while keeping loads controlled. Potential applications can be envisioned in smart structure enhanced response characteristics as desired in shock absorption, protective packaging and catching mechanisms.

  12. Distal Biceps Tendon Rupture

    DTIC Science & Technology

    2010-06-01

    distal tendon. Although these findings overlap with those seen in tendinopathy , the presence of bone marrow edema at the radial tuberosity and fluid in...the bicipitoradial bursa suggests a partial tear rather than tendinopathy .3 When the distal biceps tendon tear is complete, MR imaging shows

  13. B190 computer controlled radiation monitoring and safety interlock system

    SciTech Connect

    Espinosa, D L; Fields, W F; Gittins, D E; Roberts, M L

    1998-08-01

    The Center for Accelerator Mass Spectrometry (CAMS) in the Earth and Environmental Sciences Directorate at Lawrence Livermore National Laboratory (LLNL) operates two accelerators and is in the process of installing two new additional accelerators in support of a variety of basic and applied measurement programs. To monitor the radiation environment in the facility in which these accelerators are located and to terminate accelerator operations if predetermined radiation levels are exceeded, an updated computer controlled radiation monitoring system has been installed. This new system also monitors various machine safety interlocks and again terminates accelerator operations if machine interlocks are broken. This new system replaces an older system that was originally installed in 1988. This paper describes the updated B190 computer controlled radiation monitoring and safety interlock system.

  14. Carbon nanotube Archimedes screws.

    PubMed

    Oroszlány, László; Zólyomi, Viktor; Lambert, Colin J

    2010-12-28

    Recently, nanomechanical devices composed of a long stationary inner carbon nanotube and a shorter, slowly rotating outer tube have been fabricated. In this paper, we study the possibility of using such devices as nanoscale transducers of motion into electricity. When the outer tube is chiral, we show that such devices act like quantum Archimedes screws, which utilize mechanical energy to pump electrons between reservoirs. We calculate the pumped charge from one end of the inner tube to the other, driven by the rotation of a chiral outer nanotube. We show that the pumped charge can be greater than one electron per 360° rotation, and consequently, such a device operating with a rotational frequency of 10 MHz, for example, would deliver a current of ≈1 pAmp.

  15. Spline screw autochanger

    NASA Astrophysics Data System (ADS)

    Vranish, John M.

    1993-06-01

    A captured nut member is located within a tool interface assembly and being actuated by a spline screw member driven by a robot end effector. The nut member lowers and rises depending upon the directional rotation of the coupling assembly. The captured nut member further includes two winged segments which project outwardly in diametrically opposite directions so as to engage and disengage a clamping surface in the form of a chamfered notch respectively provided on the upper surface of a pair of parallel forwardly extending arm members of a bifurcated tool stowage holster which is adapted to hold and store a robotic tool including its end effector interface when not in use. A forward and backward motion of the robot end effector operates to insert and remove the tool from the holster.

  16. 1. ENVIRONMENT, FROM NORTHWEST, SHOWING B&P INTERLOCKING TOWER AND POWER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. ENVIRONMENT, FROM NORTHWEST, SHOWING B&P INTERLOCKING TOWER AND POWER SUBSTATIONS - Baltimore & Potomac Interlocking Tower, Adjacent to AMTRAK railroad tracks in block bounded by Howard Street, Jones Falls Expressway, Maryland Avenue & Falls Road, Baltimore, Independent City, MD

  17. Intramedullary Tibial Nail Fixation of Simple Intraarticular Distal Tibia Fractures.

    PubMed

    Scolaro, John A; Broghammer, Francis H; Donegan, Derek J

    2016-11-01

    The optimal treatment strategy for distal tibia fractures, especially those with intraarticular extension, remains controversial. Although open reduction and internal fixation with a plate and screw device is commonly performed for these injuries, the risk of soft tissue complications using this approach is significant. Staged treatment protocols and alternative means of fixation have been proposed to address these undesired events. Although potentially more technically demanding than fixation of diaphyseal or extraarticular tibial fractures, intramedullary nail (IMN) fixation of simple intraarticular distal tibia fractures is a viable treatment alternative with unique advantages. This article presents a review of the literature and rationale for intramedullary tibial nail fixation of simple intraarticular distal tibia fractures and a surgical approach commonly utilized for successful implementation.

  18. 49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Electromechanical interlocking machine; locking... Electromechanical interlocking machine; locking between electrical and mechanical levers. In electro-mechanical interlocking machine, locking between electric and mechanical levers shall be maintained so that...

  19. 49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Electromechanical interlocking machine; locking... Electromechanical interlocking machine; locking between electrical and mechanical levers. In electro-mechanical interlocking machine, locking between electric and mechanical levers shall be maintained so that...

  20. 49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Electromechanical interlocking machine; locking... Electromechanical interlocking machine; locking between electrical and mechanical levers. In electro-mechanical interlocking machine, locking between electric and mechanical levers shall be maintained so that...

  1. 46 CFR 111.91-1 - Power, control, and interlock circuits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Power, control, and interlock circuits. 111.91-1 Section... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Elevators and Dumbwaiters § 111.91-1 Power, control, and interlock circuits. Each electric power, control, and interlock circuit of an elevator or dumbwaiter must meet...

  2. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312 Transportation Other Regulations Relating to... SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.312 Movable bridge, interlocking of...

  3. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312 Transportation Other Regulations Relating to... SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.312 Movable bridge, interlocking of...

  4. 12 CFR 250.410 - Interlocking relationships between bank and its commingled investment account.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Interlocking relationships between bank and its... Section 32 of the Glass-Steagall Act § 250.410 Interlocking relationships between bank and its commingled... Banking Act of 1933 in view of the interlocking relationships that would exist between the bank...

  5. 49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Electromechanical interlocking machine; locking between electrical and mechanical levers. In electro-mechanical interlocking machine, locking between electric and mechanical levers shall be maintained so that mechanical... 49 Transportation 4 2010-10-01 2010-10-01 false Electromechanical interlocking machine;...

  6. 49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Electromechanical interlocking machine; locking between electrical and mechanical levers. In electro-mechanical interlocking machine, locking between electric and mechanical levers shall be maintained so that mechanical... 49 Transportation 4 2011-10-01 2011-10-01 false Electromechanical interlocking machine;...

  7. 46 CFR 111.70-7 - Remote control, interlock, and indicator circuits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Remote control, interlock, and indicator circuits. 111... Remote control, interlock, and indicator circuits. (a) Overcurrent protection. A conductor of a control, interlock, or indicator circuit of a motor controller must be protected against overcurrent unless: (1)...

  8. 12 CFR 212.9 - Effect of Interlocks Act on Clayton Act.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 2 2011-01-01 2011-01-01 false Effect of Interlocks Act on Clayton Act. 212.9 Section 212.9 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MANAGEMENT OFFICIAL INTERLOCKS § 212.9 Effect of Interlocks Act on Clayton Act. The Board regards...

  9. 12 CFR 212.9 - Effect of Interlocks Act on Clayton Act.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 2 2012-01-01 2012-01-01 false Effect of Interlocks Act on Clayton Act. 212.9 Section 212.9 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MANAGEMENT OFFICIAL INTERLOCKS § 212.9 Effect of Interlocks Act on Clayton Act. The Board regards...

  10. 12 CFR 212.9 - Effect of Interlocks Act on Clayton Act.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 2 2014-01-01 2014-01-01 false Effect of Interlocks Act on Clayton Act. 212.9 Section 212.9 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MANAGEMENT OFFICIAL INTERLOCKS § 212.9 Effect of Interlocks Act on Clayton Act. The Board regards...

  11. 12 CFR 212.9 - Effect of Interlocks Act on Clayton Act.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 2 2013-01-01 2013-01-01 false Effect of Interlocks Act on Clayton Act. 212.9 Section 212.9 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MANAGEMENT OFFICIAL INTERLOCKS § 212.9 Effect of Interlocks Act on Clayton Act. The Board regards...

  12. 12 CFR 212.9 - Effect of Interlocks Act on Clayton Act.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Effect of Interlocks Act on Clayton Act. 212.9 Section 212.9 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MANAGEMENT OFFICIAL INTERLOCKS § 212.9 Effect of Interlocks Act on Clayton Act. The Board regards...

  13. Distal ulnar growth arrest.

    PubMed

    Nelson, O A; Buchanan, J R; Harrison, C S

    1984-03-01

    Four cases of arrest of distal ulnar physeal growth occurring in children ages 7 to 13 years had follow-up for 2 to 10 years. Each patient developed bowing of the radial diaphysis, ulnar translation of the distal radial epiphysis, and increased ulnar angulation of the distal radiocarpal joint surface. Growth discrepancies were documented in both the ulna (range 2.2 to 3.9 cm) and to a lesser extent the radius (range 0.2 to 1.6 cm) when compared to the opposite forearm in each patient. The progression of deformity appeared to be greatest during adolescence. Radial deviation and pronation were limited to varying degrees in each case. No patient had significant pain or functional impairment, but the cosmetic appearance was always displeasing. Indications for surgical treatment include increasing ulnar angulation of the distal radial articular surface, progressive loss of motion, and displeasing cosmetic appearance.

  14. Transphyseal Distal Humerus Fracture.

    PubMed

    Abzug, Joshua; Ho, Christine Ann; Ritzman, Todd F; Brighton, Brian

    2016-01-01

    Transphyseal distal humerus fractures typically occur in children younger than 3 years secondary to birth trauma, nonaccidental trauma, or a fall from a small height. Prompt and accurate diagnosis of a transphyseal distal humerus fracture is crucial for a successful outcome. Recognizing that the forearm is not aligned with the humerus on plain radiographs may aid in the diagnosis of a transphyseal distal humerus fracture. Surgical management is most commonly performed with the aid of an arthrogram. Closed reduction and percutaneous pinning techniques similar to those used for supracondylar humerus fractures are employed. Cubitus varus caused by a malunion, osteonecrosis of the medial condyle, or growth arrest is the most common complication encountered in the treatment of transphyseal distal humerus fractures. A corrective lateral closing wedge osteotomy can be performed to restore a nearly normal carrying angle.

  15. Distal renal tubular acidosis

    MedlinePlus

    ... get better with treatment. When to Contact a Medical Professional Call your health care provider if you have symptoms of distal renal tubular acidosis. Get medical help right away if you develop emergency symptoms ...

  16. Flammable gas interlock spoolpiece flow response test plan and procedure

    SciTech Connect

    Schneider, T.C., Fluor Daniel Hanford

    1997-02-13

    The purpose of this test plan and procedure is to test the Whittaker electrochemical cell and the Sierra Monitor Corp. flammable gas monitors in a simulated field flow configuration. The sensors are used on the Rotary Mode Core Sampling (RMCS) Flammable Gas Interlock (FGI), to detect flammable gases, including hydrogen and teminate the core sampling activity at a predetermined concentration level.

  17. Description of a system for interlocking elevated temperature mechanical tests

    SciTech Connect

    Schmale, D.T.; Poulter, G.A.

    1995-07-01

    Long term mechanical creep and fatigue testing at elevated temperatures requires reliable systems with safeguards to prevent destruction of equipment, loss of data and negative environmental impacts. Toward this goal, a computer controlled system has been developed and built for interlocking tests run on elevated temperature mechanical test facilities. Sensors for water flow, water pressure, water leakage, temperature, power and hydraulic status are monitored to control specimen heating equipment through solid state relays and water solenoid valves. The system is designed to work with the default interlocks present in the RF generators and mechanical tests systems. Digital hardware consists of two National Instruments 1/0 boards mounted in a Macintosh IIci computer. Software is written in National Instruments LabVIEW. Systems interlocked include two MTS closed loop servo controlled hydraulic test frames, one with an RF generator and one with both an RF generator and a quartz lamp furnace. Control for individual test systems is modularized making the addition of more systems simple. If any of the supporting utilities fail during tests, heating systems, chill water and hydraulics are powered down, minimizing specimen damage and eliminating equipment damage. The interlock control is powered by an uninterruptible power supply. Upon failure the cause is documented in an ASCII file.

  18. Charging/Safety-Interlock Connection For Capacitor Bank

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E.

    1990-01-01

    Electrically controlled mechanical interlock apparatus prevents connection of bank of capacitors to battery or other dc power supply until capacitors precharged to nearly full supply voltage. Precharge eliminates excessive inrush current, which damages capacitors, wires, or connectors. Circuit in apparatus also discharges capacitors after power turned off or capacitors disconnected from power supply.

  19. End-to-end azido-pinned interlocking lanthanide squares.

    PubMed

    Li, Xiao-Lei; Wu, Jianfeng; Zhao, Lang; Shi, Wei; Cheng, Peng; Tang, Jinkui

    2017-03-09

    A rare end-to-end azido-pinned interlocking lanthanide square was self-assembled using a ditopic Schiff-base (H2L) and NaN3 as ligands. Obvious ferromagnetic interaction and a record anisotropy barrier of 152(4) K among lanthanide azido-bridged SMMs in a zero dc field were observed.

  20. 12 CFR 212.4 - Interlocking relationships permitted by statute.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 2 2012-01-01 2012-01-01 false Interlocking relationships permitted by statute. 212.4 Section 212.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE... corporation operating under section 25 or section 25A of the Federal Reserve Act (12 U.S.C. 601 et seq. and...

  1. 12 CFR 212.4 - Interlocking relationships permitted by statute.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 2 2014-01-01 2014-01-01 false Interlocking relationships permitted by statute. 212.4 Section 212.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE... corporation operating under section 25 or section 25A of the Federal Reserve Act (12 U.S.C. 601 et seq. and...

  2. 12 CFR 212.4 - Interlocking relationships permitted by statute.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Interlocking relationships permitted by statute. 212.4 Section 212.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE... corporation operating under section 25 or section 25A of the Federal Reserve Act (12 U.S.C. 601 et seq. and...

  3. 12 CFR 212.4 - Interlocking relationships permitted by statute.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 2 2011-01-01 2011-01-01 false Interlocking relationships permitted by statute. 212.4 Section 212.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE... corporation operating under section 25 or section 25A of the Federal Reserve Act (12 U.S.C. 601 et seq. and...

  4. 12 CFR 212.4 - Interlocking relationships permitted by statute.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 2 2013-01-01 2013-01-01 false Interlocking relationships permitted by statute. 212.4 Section 212.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE... corporation operating under section 25 or section 25A of the Federal Reserve Act (12 U.S.C. 601 et seq. and...

  5. B & P Junction Substation & Interlocking Tower; Howard Street ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    B & P Junction Substation & Interlocking Tower; Howard Street Bridge. Baltimore, Baltimore City, MD. Sec. 1201, MP 95.85 - Northeast Railroad Corridor, Amtrak route between District of Columbia/Maryland state line & Maryland/Delaware state line, Baltimore, Independent City, MD

  6. How Does Learning Intent Affect Interlocking Directorates Dynamic?

    ERIC Educational Resources Information Center

    Simoni, Michele; Caiazza, Rosa

    2012-01-01

    Purpose: Literature on board interlocks agrees that these inter-organizational ties are effective channels to exchange information and share knowledge. However, studies that consider the nature and the amount of knowledge that firms exchange are still relatively absent. Filling this gap, this paper aims to identify four types of mechanisms that…

  7. Interlocked fabric and laminated fabric Kevlar 49/epoxy composites

    SciTech Connect

    Guess, T.R.; Reedy, E.D. Jr.

    1988-01-01

    The mechanical behavior of a novel interlocked fabric reinforced Kevlar 49/epoxy composite has been measured and compared to those of a laminated Kevlar 49 fabric composite (which served as a reference material). Both composites were 5.0 mm thick, contained the same 50% in-plane fiber volume fraction and were fabricated in a similar manner using the same Dow DER 332 epoxy, Jeffamine T403-hardened resin system. The reference material (Material 1) was reinforced with seven plies of Dupont style 1033 Kevlar 49 fabric. A photomicrograph of a section polished parallel to one of the fiber directions is shown. The interlocked fabric was designed and woven for Sandia National Laboratories by Albany International Research Co., Dedham, MA. The main design criterion was to duplicate a sewn through-the-thickness fabric used in preliminary studies. The interlocked fabric composite (Material 2) contains roughly 4% by volume of through-the-thickness fiber reinforcement for the purpose of improving interlaminar strength. A photomicrograph of a section showing the warp-aligned binder yarns interlocking the six fabric plies together is shown. 2 refs., 8 figs.

  8. Construction and biomechanical properties of polyaxial self-locking anatomical plate based on the geometry of distal tibia.

    PubMed

    Liang, Weiguo; Ye, Weixiong; Ye, Dongping; Zhou, Ziqiang; Chen, Zhiguang; Li, Aiguo; Xie, Zong-Han; Zhang, Lihai; Xu, Jiake

    2014-01-01

    In order to provide scientific and empirical evidence for the clinical application of the polyaxial self-locking anatomical plate, 80 human tibias from healthy adults were scanned by spiral CT and their three-dimensional images were reconstructed using the surface shaded display (SSD) method. Firstly, based on the geometric data of distal tibia, a polyaxial self-locking anatomical plate for distal tibia was designed and constructed. Biomechanical tests were then performed by applying axial loading, 4-point bending, and axial torsion loading on the fracture fixation models of fresh cadaver tibias. Our results showed that variation in twisting angles of lateral tibia surface was found in various segments of the distal tibia. The polyaxial self-locking anatomical plate was constructed based on the geometry of the distal tibia. Compared to the conventional anatomical locking plate, the polyaxial self-locking anatomical plate of the distal tibia provides a better fit to the geometry of the distal tibia of the domestic population, and the insertion angle of locking screws can be regulated up to 30°. Collectively, this study assesses the geometry of the distal tibia and provides variable locking screw trajectory to improve screw-plate stability through the design of a polyaxial self-locking anatomical plate.

  9. Interlock system for machine protection of the KOMAC 100-MeV proton linac

    NASA Astrophysics Data System (ADS)

    Song, Young-Gi

    2015-02-01

    The 100-MeV proton linear accelerator of the Korea Multi-purpose Accelerator Complex (KOMAC) has been developed. The beam service started this year after performing the beam commissioning. If the very sensitive and essential equipment is to be protected during machine operation, a machine interlock system is required, and the interlock system has been implemented. The purpose of the interlock system is to shut off the beam when the radio-frequency (RF) and ion source are unstable or a beam loss occurs. The interlock signal of the KOMAC linac includes a variety of sources, such as the beam loss, RF and high-voltage converter modulator faults, and fast closing valves of the vacuum window at the beam lines and so on. This system consists of a hardware-based interlock system using analog circuits and a software-based interlock system using an industrial programmable logic controller (PLC). The hardware-based interlock system has been fabricated, and the requirement has been satisfied with the results being within 10 µs. The software logic interlock system using the PLC has been connected to the framework of with the experimental physics and industrial control system (EPICS) to integrate a variety of interlock signals and to control the machine components when an interlock occurs. This paper will describe the design and the construction of the machine interlock system for the KOMAC 100-MeV linac.

  10. Effect of surface coating on the screw loosening of dental abutment screws

    NASA Astrophysics Data System (ADS)

    Park, Chan-Ik; Choe, Han-Cheol; Chung, Chae-Heon

    2004-12-01

    Regardless of the type of performed restoration, in most cases, a screw connection is employed between the abutment and implant. For this reason, implant screw loosening has remained a problem in restorative practices. The purpose of this study was to compare the surface of coated/plated screws with titanium and gold alloy screws and to evaluate the physical properties of coated/plated material after scratch tests via FE-SEM (field emission scanning electron microscopy) investigation. GoldTite, titanium screws provided by 3i (Implant Innovation, USA) and TorqTite, titanium screws by Steri-Oss (Nobel Biocare, USA) and gold screws and titanium screws by AVANA (Osstem Implant, Korea) were selected for this study. The surface, crest, and root of the abutment screws were observed by FE-SEM. A micro-diamond needle was also prepared for the scratch test. Each abutment screw was fixed, and a scratch on the surface of the head region was made at constant load and thereafter the fine trace was observed with FE-SEM. The surface of GoldTite was smoother than that of other screws and it also had abundant ductility and malleability compared with titanium and gold screws. The scratch tests also revealed that teflon particles were exfoliated easily in the screw coated with teflon. The titanium screw had rough surface and low ductility. The clinical use of gold-plated screws is recommended as a means of preventing screw loosening.

  11. Engineering interlocking DNA rings with weak physical interactions

    NASA Astrophysics Data System (ADS)

    Wu, Zai-Sheng; Shen, Zhifa; Tram, Kha; Li, Yingfu

    2014-06-01

    Catenanes are intriguing molecular assemblies for engineering unique molecular devices. The resident rings of a catenane are expected to execute unhindered rotation around each other, and to do so, they must have weak physical interactions with each other. Due to sequence programmability, DNA has become a popular material for nanoscale object engineering. However, current DNA catenanes, particularly in the single-stranded (ss) form, are synthesized through the formation of a linking duplex, which makes them less ideal as mobile elements for molecular machines. Herein we adopt a random library approach to engineer ssDNA [2] catenanes (two interlocked DNA rings) without a linking duplex. Results from DNA hybridization, double-stranded catenane synthesis and rolling circle amplification experiments signify that representative catenanes have weak physical interactions and are capable of operating as independent units. Our findings lay the foundation for exploring free-functioning interlocked DNA rings for the design of elaborate nanoscale machines based on DNA.

  12. Metal-organic frameworks with dynamic interlocked components

    NASA Astrophysics Data System (ADS)

    Vukotic, V. Nicholas; Harris, Kristopher J.; Zhu, Kelong; Schurko, Robert W.; Loeb, Stephen J.

    2012-06-01

    The dynamics of mechanically interlocked molecules such as rotaxanes and catenanes have been studied in solution as examples of rudimentary molecular switches and machines, but in this medium, the molecules are randomly dispersed and their motion incoherent. As a strategy for achieving a higher level of molecular organization, we have constructed a metal-organic framework material using a [2]rotaxane as the organic linker and binuclear Cu(II) units as the nodes. Activation of the as-synthesized material creates a void space inside the rigid framework that allows the soft macrocyclic ring of the [2]rotaxane to rotate rapidly, unimpeded by neighbouring molecular components. Variable-temperature 13C and 2H solid-state NMR experiments are used to characterize the nature and rate of the dynamic processes occurring inside this unique material. These results provide a blueprint for the future creation of solid-state molecular switches and molecular machines based on mechanically interlocked molecules.

  13. Laparoscopic Distal Pancreatectomy

    PubMed Central

    Melotti, Gianluigi; Butturini, Giovanni; Piccoli, Micaela; Casetti, Luca; Bassi, Claudio; Mullineris, Barbara; Lazzaretti, Maria Grazia; Pederzoli, Paolo

    2007-01-01

    Objective: To describe the clinical characteristics, indications, technical procedures, and outcome of a consecutive series of laparoscopic distal pancreatic resections performed by the same surgical team. Summary Background Data: Laparoscopic distal pancreatic resection has increasingly been described as a feasible and safe procedure, although accompanied by a high rate of conversion and morbidity. Methods: A consecutive series of patients affected by solid and cystic tumors were selected prospectively to undergo laparoscopic distal pancreatectomy performed by the same surgical team. Clinical characteristics as well as diagnostic preoperative assessment and intra- and postoperative data were prospectively recorded. A follow-up of at least 3 months was available for all patients. Results: Fifty-eight patients underwent laparoscopic resection between May 1999 and November 2005. All procedures were successfully performed laparoscopically, and no patient required intraoperative blood transfusion. Splenic vessel preservation was possible in 84.4% of spleen-preserving procedures. There were no mortalities. The overall median hospital stay was 9 days, while it was 10.5 days for patients with postoperative pancreatic fistulae (27.5% of all cases). Follow-up was available for all patients. Conclusions: Our experience in 58 consecutive patients was characterized by the lack of conversions and by acceptable rates of postoperative pancreatic fistulae and morbidity. Laparoscopy proved especially beneficial in patients with postoperative complications as they had a relatively short hospital stay. Solid and cystic tumors of the distal pancreas represent a good indication for laparoscopic resection whenever possible. PMID:17592294

  14. Modular safety interlock system for high energy physics experiments

    SciTech Connect

    Kieffer, J.; Golceff, B.V.

    1980-10-01

    A frequent problem in electronics systems for high energy physics experiments is to provide protection for personnel and equipment. Interlock systems are typically designed as an afterthought and as a result, the working environment around complex experiments with many independent high voltages or hazardous gas subsystems, and many different kinds of people involved, can be particularly dangerous. A set of modular hardware has been designed which makes possible a standardized, intergrated, hierarchical system's approach and which can be easily tailored to custom requirements.

  15. Availability Analysis of the Ventilation Stack CAM Interlock System

    SciTech Connect

    YOUNG, J.

    2000-08-09

    Ventilation Stack Continuous Air Monitor (CAM) Interlock System failure modes, failure frequencies, and system availability have been evaluated for the RPP. The evaluation concludes that CAM availability is as high as assumed in the safety analysis and that the current routine system surveillance is adequate to maintain this availability credited in the safety analysis, nor is such an arrangement predicted to significantly improve system availability.

  16. 116. Photocopied August 1978. NEW INTERLOCKING STEEL SHEET PILING AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    116. Photocopied August 1978. NEW INTERLOCKING STEEL SHEET PILING AT PENSTOCK 52 IN THE FALL OF 1926. THE PILES FOR SUPPORTING THE HORIZONTAL ELEMENTS OF THE NEW FOREBAY APRON ARE IN PLACE BETWEEN THE NEW SHEET PILING AND THE FOREBAY WALL. VISIBLE BEYOND THE NEW SHEET PILING IS THE TIMBER SHEET PILING DRIVEN IN 1903 BY VON SCHON TO PREVENT WASHOUTS. (1006) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  17. Access control and interlock system at the Advanced Photon Source

    SciTech Connect

    Forrestal, J.; Hogrefe, R.; Knott, M.; McDowell, W.; Reigle, D.; Solita, L.; Koldenhoven, R.; Haid, D.

    1997-08-01

    The Advanced Photon Source (APS) consists of a linac, position accumulator ring (PAR), booster synchrotron, storage ring, and up to 70 experimental beamlines. The Access Control and Interlock System (ACIS) utilizes redundant programmable logic controllers (PLCs) and a third hard-wired chain to protect personnel from prompt radiation generated by the linac, PAR, synchrotron, and storage ring. This paper describes the ACIS`s design philosophy, configuration, hardware, functionality, validation requirements, and operational experience.

  18. Neutral beam interlock system on TFTR using infrared pyrometry

    SciTech Connect

    Medley, S.S.; Kugel, H.W.; Kozub, T.A.; Lowrance, J.L.; Mastrocola, V.; Renda, G.; Young, K.M.

    1986-06-01

    Although the region of the TFTR vacuum vessel wall which is susceptible to damage by neutral beam strike is armored with a mosaic of TiC-clad POCO graphite titles, at power deposition levels above 2.5 kW/cm/sup 2/ the armor surface temperature exceeds 1200/sup 0/C within 250 ms and itself becomes susceptible to damage. In order to protect the wall armor, a neutral beam interlock system based on infrared pyrometry measurement of the armor surface temperature was installed on TFTR. For each beamline, a three-fiber-optic telescope views three areas of approx.30 cm diameter centered on the armor hot spots for the three ion sources. Each signal is fiber-optic coupled to a remote 900 nm pyrometer which feeds analog signals to the neutral beam interrupt circuits. The pyrometer interlock system is designed to interrupt each of the twelve ion sources independently within 10 ms of the temperature exceeding a threshold settable in the range of 500 to 2300/sup 0/C. A description of the pyrometer interlock system and its performance will be presented.

  19. Interlock and control systems for a sector at the APS

    SciTech Connect

    Friedman, N.

    1993-09-09

    This report describes some basic elements of the various Interlock and Control Systems associated with the Front Ends and Beamlines. Some systems serve only the Front Ends; other serve both the Front Ends and the Beamlines, while the Experimental Controls are for the Beamlines only. Specific system requirements and design specifications are not in the scope of this report. They will be presented in the descriptions of the Experimental Floor Personnel Safety System (XF-PSS or, more often, PSS) and Equipment Protection System (XF-EPS or EPS), which will expand on the overview presented here. The main focus here is on the PSS and EPS in the context of their interactions and interface to the Storage Ring Access Control Interlock System (ACIS), and Ring Controls. The other systems are only mentioned to make the cross section complete. This paper is the first in series of three reports that jointly provide a full description of sector interlocks. The second report describes the PSS, and the third -- the EPS.

  20. Flammable gas interlock spoolpiece flow response test report

    SciTech Connect

    Schneider, T.C., Fluor Daniel Hanford

    1997-03-24

    The purpose of this test report is to document the testing performed under the guidance of HNF-SD-WM-TC-073, {ital Flammable Gas Interlock Spoolpiece Flow Response Test Plan and Procedure}. This testing was performed for Lockheed Martin Hanford Characterization Projects Operations (CPO) in support of Rotary Mode Core Sampling jointly by SGN Eurisys Services Corporation and Numatec Hanford Company. The testing was conducted in the 305 building Engineering Testing Laboratory (ETL). NHC provides the engineering and technical support for the 305 ETL. The key personnel identified for the performance of this task are as follows: Test responsible engineering manager, C. E. Hanson; Flammable Gas Interlock Design Authority, G. P. Janicek; 305 ETL responsible manager, N. J. Schliebe; Cognizant RMCS exhauster engineer, E. J. Waldo/J. D. Robinson; Cognizant 305 ETL engineer, K. S. Witwer; Test director, T. C. Schneider. Other support personnel were supplied, as necessary, from 305/306 ETL. The testing, on the flammable Gas Interlock (FGI) system spoolpiece required to support Rotary Mode Core Sampling (RMCS) of single shell flammable gas watch list tanks, took place between 2-13-97 and 2-25-97.

  1. Interlocking circumareolar suture with undyed polyamide thread: a personal experience.

    PubMed

    Salgarello, Marzia; Visconti, Giuseppe; Barone-Adesi, Liliana

    2013-10-01

    In plastic breast surgery, the interlocking areolar suture has gained wide popularity since its introduction in 2007 by Hammond and colleagues. The interlocking circumareolar suture plays its role in the setting of circumareolar excisions to achieve a durable areola shaping and to prevent scar widening/hypertrophy and areola spreading/distortion. This study retrospectively reviewed 49 breasts that underwent interlocking suture after July 2011 for both aesthetic and reconstructive indications. For the suturing, 3-0 undyed polyamide thread with a straight cutting needle (Dafilon; B. Braun Melsungen AG, Melsungen, Germany) was used. This suture material was preferred to Gore-Tex reported by Hammond and colleagues because it is undyed without any microporous configuration, more wieldy, and less expensive. All 49 breasts showed good results in terms of areola shaping and diameter control as well as good scar quality during a mean follow-up period of 12 months (range 2-18 months) (Fig. 2). No infection, suture extrusion, skin fistula, or granuloma were experienced. The suture was not visible at all, and the patients did not report its palpability. However, at careful examination, the thread resulted slightly palpable.

  2. Bilateral en-masse distalization of maxillary posterior teeth with skeletal anchorage: a case report

    PubMed Central

    Noorollahian, Saeed; Alavi, Shiva; Shirban, Farinaz

    2016-01-01

    ABSTRACT Objective: The aim of this study was to introduce a new method for bilateral distal movement of the entire maxillary posterior segment. Case report: A 17-year-old girl with Class I skeletal malocclusion (end-to-end molar relationships, deviated midline and space deficiency for left maxillary canine) was referred for orthodontic treatment. She did not accept maxillary first premolars extraction. A modified Hyrax appliance (Dentaurum Ispringen, Germany) was used for bilateral distalization of maxillary posterior teeth simultaneously. Expansion vector was set anteroposteriorly. Posterior legs of Hyrax were welded to first maxillary molar bands. All posterior teeth on each side consolidated with a segment of 0.017 × 0.025-in stainless steel wire from the buccal side. Anterior legs of Hyrax were bent into eyelet form and attached to the anterior palate with two mini-screws (2 × 10 mm) (Jeil Medical Corporation Seoul, South Korea). Hyrax opening rate was 0.8 mm per month. Lateral cephalometric radiographs were used to evaluate the extent of distal movement. 3.5-mm distalization of posterior maxillary teeth was achieved in five months. Results: A nearly bodily distal movement without anchorage loss was obtained. Conclusion: The mini-screw-supported modified Hyrax appliance was found to be helpful for achieving en-masse distal movement of maxillary posterior teeth. PMID:27409657

  3. Metallurgical examination of gun barrel screws

    SciTech Connect

    Bird, E.L.; Clift, T.L.

    1996-06-01

    The examination was conducted to determine the extent of degradation that had occurred after a series of firings; these screws prevent live rounds of ammunition from being loaded into the firing chamber. One concern is that if the screw tip fails and a live round is accidentally loaded into the chamber, a live round could be fired. Another concern is that if the blunt end of the screw begins to degrade by cracking, pieces could become small projectiles during firing. All screws used in firing 100 rounds or more exhibited some degree degradation, which progressively worsened as the number of rounds fired increased. (SEM, metallography, x-ray analysis, and microhardness were used.) Presence of cracks in these screws after 100 fired rounds is a serious concern that warrants the discontinued use of these screws. The screw could be improved by selecting an alloy more resistant to thermal and chemical degradation.

  4. Interlock systems using programmable sequence controllers and a monitoring system of the Photon Factory beamlines

    NASA Astrophysics Data System (ADS)

    Satow, Yoshinori; Ito, Kenji; Kosuge, Takashi

    1989-07-01

    Fully utilizing programmable sequence controllers, interlock systems for the Photon Factory beamlines were newly designed and constructed for providing the reliable and versatile control logic that is required for beamline characteristics. The systems, accommodated with radiation safety and vacuum interlock logic as well as protection logic for various components against heat and radiation damage, are in operation on eight beamlines. A centralized monitoring system, to which all interlock systems for the beamlines are connected through optical fiber links, was constructed for simultaneously monitoring the operation status of the interlock systems. Individual operations of each interlock system are also controlled by the monitoring system. Log data collected by the monitoring system are summarized and analyzed in order to provide the necessary information for smooth and safe operation as well as for further improvements of the beamlines. The interlock and the monitoring systems are described along with operational remarks.

  5. Single absorbable polydioxanone pin fixation for distal chevron bunion osteotomies.

    PubMed

    Deorio, J K; Ware, A W

    2001-10-01

    The distal chevron osteotomy is a well-established technique for correction of symptomatic mild to moderate metatarsus primus varus with hallux valgus deformity. Fixation of the osteotomy ranges from none to bone pegs, Kirschner wires, screws, or absorbable pins. We evaluated one surgeon's (J.K.D.) results of distal chevron osteotomy fixation with a single, nonpredrilled, 1.3-mm poly-p-dioxanone pin and analyzed any differences in patients with unilateral or bilateral symptomatic metatarsus primus varus with hallux valgus deformities. All osteotomies healed without evidence of infection, osteolysis, nonunion, or necrosis. Equal correction was achieved in unilateral and bilateral procedures. The technique is quick and easy, and adequate fixation is achieved.

  6. Distal Radioulnar Joint Instability

    PubMed Central

    Mirghasemi, Ali R.; Lee, Daniel J.; Rahimi, Narges; Rashidinia, Shervin

    2015-01-01

    Distal radioulnar joint (DRUJ) instability is a common clinical condition but a frequently missed diagnosis. Both surgical and nonsurgical treatments are possible for chronic cases of DRUJ instability. Nonsurgical treatment can be considered as the primary therapy in less active patients, while surgery should be considered to recover bone and ligament injuries if nonsurgical treatment fails to restore forearm stability and function. The appropriate choice of treatment depends on the individual patient and specific derangement of the DRUJ PMID:26328241

  7. Distal radioulnar joint injuries

    PubMed Central

    Thomas, Binu P; Sreekanth, Raveendran

    2012-01-01

    Distal radioulnar joint is a trochoid joint relatively new in evolution. Along with proximal radioulnar joint, forearm bones and interosseous membrane, it allows pronosupination and load transmission across the wrist. Injuries around distal radioulnar joint are not uncommon, and are usually associated with distal radius fractures,fractures of the ulnar styloid and with the eponymous Galeazzi or Essex_Lopresti fractures. The injury can be purely involving the soft tissue especially the triangular fibrocartilage or the radioulnar ligaments. The patients usually present with ulnar sided wrist pain, features of instability, or restriction of rotation. Difficulty in carrying loads in the hand is a major constraint for these patients. Thorough clinical examination to localize point of tenderness and appropriate provocative tests help in diagnosis. Radiology and MRI are extremely useful, while arthroscopy is the gold standard for evaluation. The treatment protocols are continuously evolving and range from conservative, arthroscopic to open surgical methods. Isolated dislocation are uncommon. Basal fractures of the ulnar styloid tend to make the joint unstable and may require operative intervention. Chronic instability requires reconstruction of the stabilizing ligaments to avoid onset of arthritis. Prosthetic replacement in arthritis is gaining acceptance in the management of arthritis. PMID:23162140

  8. Results of screw epiphysiodesis for the treatment of limb length discrepancy and angular deformity.

    PubMed

    Khoury, Joseph G; Tavares, Joao O; McConnell, Sharon; Zeiders, Gregory; Sanders, James O

    2007-09-01

    The purpose of this study was to evaluate the technique of screw epiphysiodesis for effectiveness, predictability, and reversibility. We reviewed the cases of our first 60 patients (105 physes) treated with percutaneous screw epiphysiodesis or hemiepiphysiodesis. All cases were followed up to maturity or screw removal if growth remained after full correction. A total of 30 patients underwent the procedure for limb length inequality. Final inequality was compared with the predicted epiphysiodesis effect. A total of 30 patients (66 physes) underwent screw hemiepiphysiodesis for the correction of angular deformity. The degree of correction per month was calculated, the reversibility of the procedure was analyzed, and complications were evaluated. In the length group, at the end of treatment, the final limb length difference in the femur averaged 0.15 cm (SD, +/-0.37 cm) from the epiphysiodesis effect predicted by using the multiplier method. In the tibia, this difference was 0.05 cm (SD, +/-0.57 cm). In the angular group, the average correction in the distal femur was 6.91 degrees (SD, +/-3.75 degrees) or 0.75 degrees per month (SD, +/-0.45 degrees per month). In the proximal tibia, the average correction was 3.88 degrees (SD, +/-3.57 degrees) or 0.37 degrees per month (SD, +/-0.34 degrees per month). In all 13 cases where the screws were removed at the time of angular correction with significant growth remaining, growth resumed. Complications were minor and were related to incorrect placement of screws or minor hardware irritation. Percutaneous screw epiphysiodesis is a reliable, minimally invasive method with reliable results in both length and angular correction, with minimal morbidity, and with an acceptable complication rate.

  9. Guided growth with a noncannulated screw-plate system for angular deformity of the knee: a preliminary report.

    PubMed

    Lee, Hyun-Joo; Oh, Chang-Wug; Song, Kwang-Soon; Kyung, Hee-Soo; Min, Woo-Kie; Park, Byung-Chul

    2012-07-01

    We assessed the result of guided growth for an angular knee deformity using a 3.5-mm noncannulated screw-plate system. Twenty-seven patients with angular deformities (10 distal femora, 13 proximal tibiae, and four both areas) underwent this procedure with the reconstruction plate and two noncannulated screws. Average age at the time of the procedure was 7.8 years and the average follow-up was 25.7 months. Except for one patient (two knees), 25 of 27 deformities showed a resolved outcome with a neutral alignment. The mechanical lateral distal femoral angle changed an average of 8.3° for 13 months and the medial proximal tibial angle changed an average of 7.7° for 11.8 months in the neutral state. The mean angle between the two screws was -2° in immediate postoperative radiographs and 23° in radiographs taken at the latest follow-up. Two patients showed a rebound outcome and one showed a failure of no correction. There was a superficial infection, but no mechanical failure of the screw and the plate was observed. The noncannulated screw-plate system may play a similar role of guided growth, to correct angular knee deformity, although a large series study with a long follow-up is required for a definitive conclusion.

  10. Screw-fed pump system

    SciTech Connect

    Sprouse, Kenneth M

    2014-11-25

    A pump system includes a pump that includes a first belt and a second belt that are spaced apart from each other to provide generally straight sides of a passage there between. There is an inlet at one end of the passage and an outlet at an opposite end of the passage, with a passage length that extends between the inlet and the outlet. The passage defines a gap distance in a width direction between the straight sides at the passage inlet. A hopper includes an interior space that terminates at a mouth at the passage inlet. At least one screw is located within the interior space of the hopper and includes a screw diameter in the width direction that is less than or equal to the gap distance.

  11. Helical screw expander evaluation project

    NASA Astrophysics Data System (ADS)

    McKay, R.

    1982-03-01

    A one MW helical rotary screw expander power system for electric power generation from geothermal brine was evaluated. The technology explored in the testing is simple, potentially very efficient, and ideally suited to wellhead installations in moderate to high enthalpy, liquid dominated field. A functional one MW geothermal electric power plant that featured a helical screw expander was produced and then tested with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing, operation on two-phase geothermal fluids. The Project also produced a computer equipped data system, an instrumentation and control van, and a 1000 kW variable load bank, all integrated into a test array designed for operation at a variety of remote test sites. Data are presented for the Utah testing and for the noncondensing phases of the testing in Mexico. Test time logged was 437 hours during the Utah tests and 1101 hours during the Mexico tests.

  12. Helical screw expander evaluation project

    NASA Technical Reports Server (NTRS)

    Mckay, R.

    1982-01-01

    A one MW helical rotary screw expander power system for electric power generation from geothermal brine was evaluated. The technology explored in the testing is simple, potentially very efficient, and ideally suited to wellhead installations in moderate to high enthalpy, liquid dominated field. A functional one MW geothermal electric power plant that featured a helical screw expander was produced and then tested with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing, operation on two-phase geothermal fluids. The Project also produced a computer equipped data system, an instrumentation and control van, and a 1000 kW variable load bank, all integrated into a test array designed for operation at a variety of remote test sites. Data are presented for the Utah testing and for the noncondensing phases of the testing in Mexico. Test time logged was 437 hours during the Utah tests and 1101 hours during the Mexico tests.

  13. An evaluation of the Swedish ignition interlock program.

    PubMed

    Bjerre, Bo

    2003-01-01

    The Swedish alcohol ignition interlock program for driving while intoxicated (DWI) offenders, both first-time as well as multiple offenders, was launched as a pilot project in 1999. It is a volunteer program and differs in some respects from other programs: It covers a period of 2 years, it includes very strict medical regulations entailing regular checkups by a physician, it does not require a prior period of hard suspension, and it focuses strongly on changes in alcohol habits. Records from the 5 years prior to the offence showed that DWI offenders are generally in a high-risk category long before their offense, with a four to five times higher accident rate (road accidents reported by the police) and a three to four times higher rate of hospitalization due to a road accident. Only 12% of the eligible DWI offenders took part in the program and, of these, 60% could be diagnosed as alcohol dependent or alcohol abusers. During the program, alcohol consumption is monitored through self-esteem questionnaires (AUDIT) and five different biological markers. Our data show a noticeable reduction in alcohol consumption among the interlock users. This, combined with the high rate of compliance with the regulations, probably accounts for the fact that there was no case of recidivism during the program. Preliminary findings also suggest a reduction in the annual accident rate for interlock users while in the program. It still is too early to draw any conclusions concerning the rate of recidivism after completion of the program due to an insufficient amount of data for analysis. Nevertheless, the preliminary results are so promising that the program will now be expanded to cover all of Sweden as well as to include all driver's license categories.

  14. National Synchrotron Light Source angiography personnel protection interlock

    SciTech Connect

    Gmuer, N.; Larson, R.; Thomlinson, W.

    1992-06-01

    This document has been written to describe the safety system operation at the NSLS X17B2 beamline Synchrotron Medical Research Facility (SMERF). The angiography exposure process involves scanning a patient up and down through dual fixed-position x-ray beams; exposure is controlled by opening and closing a fast-acting Safety Shutter mechanism at precise times in relation to the up and down motion of the scan chair. The fast-acting Safety Shutter mechanism is the primary radiation-stopping element protecting the patient while the chair is at rest and while it is reversing directions during the scan. Its fail-safe and fast operation is essential for the safety of the patient. Operation of X17B2 as a human subject angiography station necessitates the implementation of a personnel protection interlock system that, in conjunction with the Safety Shutters: permits safe access to the patient exposure area while the synchrotron radiation beam is illuminating the upstream dual energy monochromator; allows a patient to be imaged by the monochromatized beam under the supervision of a Responsible Physician, with scan chair motion and precision shutter actuation regulated by an angiography control computer, while providing a suitable number of safeguards against accidental radiation exposure; has different modes of operation to accommodate equipment set-up, test, and calibration; and patient exposure; and ensures the quick extinction of the beam if a potentially unsafe condition is detected. The interlock system which performs these safety functions is called the Angiography Personnel Protection Interlock (APPI). The APPI Document is organized such that the level of detail changes from a general overview to detailed engineering drawings of the hardware system.

  15. Stable three-dimensional metallic carbon with interlocking hexagons

    PubMed Central

    Zhang, Shunhong; Wang, Qian; Chen, Xiaoshuang; Jena, Puru

    2013-01-01

    Design and synthesis of 3D metallic carbon that is stable under ambient conditions has been a long-standing dream. We predict the existence of such phases, T6- and T14-carbon, consisting of interlocking hexagons. Their dynamic, mechanical, and thermal stabilities are confirmed by carrying out a variety of state-of-the-art theoretical calculations. Unlike the previously studied K4 and the simple cubic high pressure metallic phases, the structures predicted in this work are stable under ambient conditions. Equally important, they may be synthesized chemically by using benzene or polyacenes molecules. PMID:24191020

  16. Photovoltaic module and interlocked stack of photovoltaic modules

    DOEpatents

    Wares, Brian S.

    2012-09-04

    One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame having at least a top member and a bottom member. A plurality of alignment features are included on the top member of each frame, and a plurality of alignment features are included on the bottom member of each frame. Adjacent photovoltaic modules are interlocked by the alignment features on the top member of a lower module fitting together with the alignment features on the bottom member of an upper module. Other embodiments, features and aspects are also disclosed.

  17. Photovoltaic module and interlocked stack of photovoltaic modules

    DOEpatents

    Wares, Brian S.

    2014-09-02

    One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame. A plurality of individual male alignment features and a plurality of individual female alignment features are included on each frame. Adjacent photovoltaic modules are interlocked by multiple individual male alignment features on a first module of the adjacent photovoltaic modules fitting into and being surrounded by corresponding individual female alignment features on a second module of the adjacent photovoltaic modules. Other embodiments, features and aspects are also disclosed.

  18. Volar Locking Plate Breakage after Nonunion of a Distal Radius Osteotomy

    PubMed Central

    Rodríguez-Alabau, Sergi; Soldado, Francisco; Mir, Xavier

    2016-01-01

    We report a 38-year-old male with a nonunion followed by plate breakage after volar plating of a distal radius osteotomy. Volar locking plates have added a new approach to the treatment of distal radius malunions, due to a lower morbidity of the surgical approach and the strength of the final construction, allowing early mobilization and return to function. Conclusion. Plate breakage is an uncommon complication of volar locking plate fixation. To our knowledge, few cases have been described after a distal radius fracture and no case has been described after a distal radius corrective osteotomy. In the present case, plate breakage appears to have occurred as a result of a combination of multiple factors as the large corrective lengthening osteotomy, the use of demineralized bone matrix instead of bone graft, and the inappropriate fixation technique as an unfilled screw on the osteotomy site, rather than the choice of plate. PMID:28003828

  19. Sauvé-Kapandji procedure for disorders of the distal radioulnar joint: a simplified technique.

    PubMed

    Rothwell, A G; O'Neill, L; Cragg, K

    1996-09-01

    A simplified technique of the Sauvé-Kapandji (SK) procedure for disorders of the distal radioulnar joint (DRUJ) is described. The DRUJ is transfixed by a screw but is not formally exposed and fused, the periosteum of the distal ulna is not excised, and the pronator quadratus is not advanced into the pseudarthrosis. Stability of the ulna shaft is obtained by suturing the sheath of the extensor carpi ulnaris (ECU) and periosteum as a single layer firmly over the ulnar stump and pseudarthrosis. The operating time averages 20 minutes. Review of 28 wrists demonstrated relief of pain in 27; 80 degrees or greater of pronation and supination in 19 and 20, respectively; fusion of the DRUJ in 18; and ulnar carpal shift in 3. The main complications were related to screw placement and length and prominence of the ECU tendon. The simplified SK procedure reliably relieves pain and restores movement at the DRUJ.

  20. Shock-Absorbent Ball-Screw Mechanism

    NASA Technical Reports Server (NTRS)

    Hirr, Otto A., Jr.; Meneely, R. W.

    1986-01-01

    Actuator containing two ball screws in series employs Belleville springs to reduce impact loads, thereby increasing life expectancy. New application of springs increases reliability of equipment in which ball screws commonly used. Set of three springs within lower screw of ball-screw mechanism absorbs impacts that result when parts reach their upper and lower limits of movement. Mechanism designed with Belleville springs as shock-absorbing elements because springs have good energy-to-volume ratio and easily stacked to attain any stiffness and travel.

  1. Distal tibiofibular radiological overlap

    PubMed Central

    Sowman, B.; Radic, R.; Kuster, M.; Yates, P.; Breidiel, B.; Karamfilef, S.

    2012-01-01

    Objectives Overlap between the distal tibia and fibula has always been quoted to be positive. If the value is not positive then an injury to the syndesmosis is thought to exist. Our null hypothesis is that it is a normal variant in the adult population. Methods We looked at axial CT scans of the ankle in 325 patients for the presence of overlap between the distal tibia and fibula. Where we thought this was possible we reconstructed the images to represent a plain film radiograph which we were able to rotate and view in multiple planes to confirm the assessment. Results The scans were taken for reasons other than pathology of the ankle. We found there was no overlap in four patients. These patients were then questioned about previous injury, trauma, surgery or pain, in order to exclude underlying pathology. Conclusion We concluded that no overlap between the tibia and fibula may exist in the population, albeit in a very small proportion. PMID:23610666

  2. 46 CFR 111.91-1 - Power, control, and interlock circuits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Power, control, and interlock circuits. 111.91-1 Section 111.91-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING... circuits. Each electric power, control, and interlock circuit of an elevator or dumbwaiter must meet...

  3. 30 CFR 75.819 - Motor-starter enclosures; barriers and interlocks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Motor-starter enclosures; barriers and...-Voltage Distribution High-Voltage Longwalls § 75.819 Motor-starter enclosures; barriers and interlocks. Compartment separation and cover interlock switches for motor-starter enclosures must be maintained...

  4. 30 CFR 75.819 - Motor-starter enclosures; barriers and interlocks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Motor-starter enclosures; barriers and...-Voltage Distribution High-Voltage Longwalls § 75.819 Motor-starter enclosures; barriers and interlocks. Compartment separation and cover interlock switches for motor-starter enclosures must be maintained...

  5. 49 CFR 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... sequence, starter interlock, and transmission braking effect. 571.102 Section 571.102 Transportation Other... braking effect. S1. Purpose and scope. This standard specifies the requirements for the transmission shift position sequence, a starter interlock, and for a braking effect of automatic transmissions, to reduce...

  6. 49 CFR 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... sequence, starter interlock, and transmission braking effect. 571.102 Section 571.102 Transportation Other... braking effect. S1. Purpose and scope. This standard specifies the requirements for the transmission shift position sequence, a starter interlock, and for a braking effect of automatic transmissions, to reduce...

  7. 49 CFR 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... sequence, starter interlock, and transmission braking effect. 571.102 Section 571.102 Transportation Other... braking effect. S1. Purpose and scope. This standard specifies the requirements for the transmission shift position sequence, a starter interlock, and for a braking effect of automatic transmissions, to reduce...

  8. Mechanically Interlocked Molecules Assembled by π–π Recognition

    SciTech Connect

    Barin, Gokhan; Coskun, Ali; Fouda, Moustafa M. G.; Stoddart, J. Fraser

    2012-02-28

    The beauty and utility of interlocked architectures have been making their way relentlessly into chemistry in the form of mechanically interlocked molecules (MIMs) for almost half a century now. Few would challenge the assertion that the emergence of template-directed synthetic protocols has aided and abetted the facile and efficient construction of MIMs compared with the statistical approaches employed while the field was still in its infancy. To date, a panoply of MIMs has been created in the wake of emerging recognition motifs and the template-directed synthetic protocols they have forged. Among these motifs, those dependent on π–π stacking in the form of donor–acceptor interactions have played an important role in the increasingly rapid development of the field. The few integrated systems that have so far emerged based on this class of MIMs demonstrate their ability to act as active components in many potential applications. This review focuses on the progress which has been accomplished during the past decade involving MIMs comprising aromatic π–π stacking interactions. While progress has been remarkable, opportunities still abound for MIMs assembled by π–π recognition.

  9. A Biomechanical Comparison of Expansive Pedicle Screws for Severe Osteoporosis: The Effects of Screw Design and Cement Augmentation

    PubMed Central

    Tai, Ching-Lung; Tsai, Tsung-Ting; Lai, Po-Liang; Chen, Yi-Lu; Liu, Mu-Yi; Chen, Lih-Huei

    2015-01-01

    Expansive pedicle screws significantly improve fixation strength in osteoporotic spines. However, the previous literature does not adequately address the effects of the number of lengthwise slits and the extent of screw expansion on the strength of the bone/screw interface when expansive screws are used with or without cement augmentation. Herein, four designs for expansive pedicle screws with different numbers of lengthwise slits and different screw expansion levels were evaluated. Synthetic bones simulating severe osteoporosis were used to provide a comparative platform for each screw design. The prepared specimens were then tested for axial pullout failure. Regardless of screw design, screws with cement augmentation demonstrated significantly higher pullout strength than pedicle screws without cement augmentation (p < 0.001). For screws without cement augmentation, solid screws exhibited the lowest pullout strength compared to the four expansive groups (p < 0.01). No significant differences in pullout strength were observed between the expansive screws with different designs (p > 0.05). Taken together, our results show that pedicle screws combined with cement augmentation may greatly increase screw fixation regardless of screws with or without expansion. An increase in both the number of slits and the extent of screw expansion had little impact on the screw-anchoring strength. Cement augmentation is the most influential factor for improving screw pullout strength. PMID:26720724

  10. Evaluation of a program to motivate impaired driving offenders to install ignition interlocks.

    PubMed

    Voas, R B; Blackman, K O; Tippetts, A S; Marques, P R

    2001-01-01

    Approximately 30,000 alcohol ignition interlocks, which prevent a drinking driver from operating a vehicle, are in use in the United States and Canada. Currently available studies indicate that interlocks reduce impaired driving recidivism while on the vehicle. However, in the United States, the practical effectiveness of these devices is limited because few offenders are willing to install them in order to drive legally. This paper reports on a study of a court policy that created a strong incentive for impaired driving offenders to install interlocks by making penalties (e.g., jail or electronically monitored house arrest) the alternative to the interlock. Comparison of the recidivism rates of offenders subject to this policy with offenders in similar, nearby courts not using interlocks indicated that the policy was producing substantial reductions in DUI recidivism.

  11. [Growth prognosis after para-epiphyseal tangential epiphysial injuries of the lower extremity exemplified by the distal femur: outcome after injuries of epiphyses of the distal femur].

    PubMed

    Weinberg, A M; Castellani, C; Werner, C; Mayr, J

    2002-01-01

    Fractures of the distal end of the femur are rare. Premature partial closure of the physis may occur after metaphyseal fractures. After epiphyseal fractures it has a high incidence of occurrence. The cause of physeal arrest is not known. Stimulation of the physes ends in leg length discrepancy and was seen in 50% of all cases. Spontaneous correction of an axis deviation is possible after antecurvation up to an age of 5 years. But this should be only accepted during therapy of metaphyseal fractures of the distal femur. Side-to-Side deviations remodel in all cases. Aim of therapy in distal epiphyseal fractures should be an anatomical reduction and a definitive retention. Screw osteosynthesis seems to have an advantage.

  12. True anteroposterior view pedicle screw insertion technique

    PubMed Central

    Bai, Jia-yue; Zhang, Wei; An, Ji-long; Sun, Ya-peng; Ding, Wen-yuan; Shen, Yong

    2016-01-01

    Background The wide use of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) surgery in the treatment of degenerative disc disease of lumbar spine in spinal surgery highlights the gradual decrease in the use of traditional pedicle screw insertion technology. This study aims to analyze the accuracy of the true anteroposterior view pedicle screw insertion technique in MIS-TLIF surgery, compare it with conventional pedicle screw insertion technology, and discuss its clinical application value. Methods Fifty-two patients undergoing true anteroposterior view (group A) and 87 patients undergoing conventional pedicle screw insertion (group B) were diagnosed with lumbar disc herniation or lumbar spinal stenosis. Time for screw placement, intraoperative irradiation exposure, accuracy rate of pedicle screw insertion, and incidence of neurovascular injury were compared between the two groups. Results The time for screw placement and intraoperative irradiation exposure was significantly less in group A. Penetration rates of the paries lateralis of vertebral pedicle, medial wall of vertebral pedicle, and anterior vertebral wall were 1.44%, 0%, and 2.40%, respectively, all of which were significantly lower than that in group B. No additional serious complications caused by the placement of screw were observed during the follow-up period in patients in group A, but two patients with medial penetration underwent revision for unbearable radicular pain. Conclusion The application of true anteroposterior view pedicle screw insertion technique in MIS-TLIF surgery shortens time for screw placement and reduces the intraoperative irradiation exposure along with a higher accuracy rate of screw placement, which makes it a safe, accurate, and efficient technique. PMID:27418828

  13. Distal arthrogryposis syndrome

    PubMed Central

    Kulkarni, K. P.; Panigrahi, I.; Ray, M.; Marwaha, R. K.

    2008-01-01

    A 5-month-old male infant presented with weak cry, decreased body movements, tightness of whole body since birth, and one episode of generalized seizure on day 4 of life. He was born at term by elective caesarian section performed for breech presentation. The child had failure to thrive, contractures at elbow and knee joints, hypertonia, microcephaly, small mouth, retrognathia, and camptodactyly. There was global developmental delay. Abdominal examination revealed umbilical and bilateral inguinal hernia. Visual evoked response and brainstem evoked response audiometry were abnormal. Nerve conduction velocity was normal. Magnetic resonance imaging of brain revealed paucity of white matter in bilateral cerebral hemispheres with cerebellar and brain stem atrophy. The differential diagnoses considered in the index patient were distal arthrogryposis (DA) syndrome, cerebroculofacioskeletal syndrome, and Pena Shokier syndrome. The index patient most likely represents a variant of DA: Sheldon Hall syndrome. PMID:20300297

  14. Comparing the Intramedullary Nailing Method Versus Dynamic Hip Screw in Treatment of Unstable Intertrochanteric Fractures

    PubMed Central

    Yeganeh, Ali; Taghavi, Roozbeh; Moghtadaei, Mehdi

    2016-01-01

    Introduction: Dynamic Hip Screw fixation is currently considered as a standard treatment for pre-trochanteric fractures; however, due to the long-term hospitalization and some other complications, some researchers have proposed intramedullary nailing as the alternative surgical treatment. The aim of this study was to compare and examine the consequences of the using intramedullary nailing method versus Dynamic Hip Screw. Methods: In this study 114 patients with unstable Intertrochanteric fracture refer to Rasoul Akram hospital during 2011 to 2013 has been selected. After reduction, fixation surgery with PFN nail (60 patients) and Dynamic Hip Screw (54 patients) has been performed. All patients were screen during surgery and six months after surgery and some parameters like, bleeding, union, as well as complications such as collapse, varus and medialization of the distal fragment were record and patients. Results: About some parameters like cutting length, surgery duration, bleeding there were significant differences between two groups. In six months follow up period 2 patinas from nail and 8 patients from DHS group had non-union. Also from the point of radiologic and clinical parameters, like anterior thigh pain, cut out, medialization of the distal fragment, collapse of the neck, walking recovery and daily activities were significant between two groups. Conclusion: Due to the reduced hospital stay in intramedullary nailing method and the necessity of doing repeated surgery and applying intramedullary nailing when the patients are not treated with external fixation, the researchers recommend intramedullary nailing as the first option in treating such patients. PMID:26980933

  15. Twin screw granulation: steps in granule growth.

    PubMed

    Dhenge, Ranjit M; Cartwright, James J; Hounslow, Michael J; Salman, Agba D

    2012-11-15

    The present work focuses on the study of the progression of granules in different compartments along the length of screws in a twin screw granulator (TSG). The effects of varying powder feed rate; liquid to solid ratio and viscosity of granulation liquid on properties of granules was studied. The bigger granules produced at the start of the process were found to change in terms of size, shape and strength along the screw length at all the conditions investigated. The granules became more spherical and their strength increased along the screw length. Tracer granules were also introduced in order to understand the role of kneading and conveying elements in the TSG. The kneading elements promoted consolidation and breakage while the conveying elements led to coalescence, breakage and some consolidation. The results presented here help to provide a qualitative and quantitative understanding of the twin screw granulation process.

  16. Allergic reaction to biodegradable interference poly-L-lactic acid screws after anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft.

    PubMed

    Mastrokalos, Dimitrios S; Paessler, Hans H

    2008-06-01

    We report a case of a systemic allergic reaction to biodegradable poly-L-lactic acid (PLLA) interference screws after anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone graft. A 30-year-old patient complained of certain symptoms, such as an inability to focus mentally, rash on the right femur, chronic fatigue, decreased sex drive, and localized alopecia, 3 months after ACL reconstruction in the right knee. Two biodegradable PLLA interference screws had been used for proximal and distal graft fixation. Allergy testing showed a value of 7 in PLLA antigen. After removal of 1 screw in August 2000, the patient reported marked improvement, but some symptoms remained. In July 2001 he underwent arthroscopic revision ACL reconstruction with hamstrings via an implant-free technique with intensive debridement of the tunnels and removal of all scar tissue and screw rests. All symptoms disappeared, and the PLLA antigen number fell from 3 to "concentrate" 2 months postoperatively.

  17. Long-range movement of large mechanically interlocked DNA nanostructures

    NASA Astrophysics Data System (ADS)

    List, Jonathan; Falgenhauer, Elisabeth; Kopperger, Enzo; Pardatscher, Günther; Simmel, Friedrich C.

    2016-08-01

    Interlocked molecules such as catenanes and rotaxanes, connected only via mechanical bonds have the ability to perform large-scale sliding and rotational movements, making them attractive components for the construction of artificial molecular machines and motors. We here demonstrate the realization of large, rigid rotaxane structures composed of DNA origami subunits. The structures can be easily modified to carry a molecular cargo or nanoparticles. By using multiple axle modules, rotaxane constructs are realized with axle lengths of up to 355 nm and a fuel/anti-fuel mechanism is employed to switch the rotaxanes between a mobile and a fixed state. We also create extended pseudo-rotaxanes, in which origami rings can slide along supramolecular DNA filaments over several hundreds of nanometres. The rings can be actively moved and tracked using atomic force microscopy.

  18. Long-range movement of large mechanically interlocked DNA nanostructures

    PubMed Central

    List, Jonathan; Falgenhauer, Elisabeth; Kopperger, Enzo; Pardatscher, Günther; Simmel, Friedrich C.

    2016-01-01

    Interlocked molecules such as catenanes and rotaxanes, connected only via mechanical bonds have the ability to perform large-scale sliding and rotational movements, making them attractive components for the construction of artificial molecular machines and motors. We here demonstrate the realization of large, rigid rotaxane structures composed of DNA origami subunits. The structures can be easily modified to carry a molecular cargo or nanoparticles. By using multiple axle modules, rotaxane constructs are realized with axle lengths of up to 355 nm and a fuel/anti-fuel mechanism is employed to switch the rotaxanes between a mobile and a fixed state. We also create extended pseudo-rotaxanes, in which origami rings can slide along supramolecular DNA filaments over several hundreds of nanometres. The rings can be actively moved and tracked using atomic force microscopy. PMID:27492061

  19. Detection of phosphatidylethanol (PEth) in the blood of drivers in an alcohol ignition interlock program

    PubMed Central

    Marques, Paul; Hansson, Therese; Isaksson, Anders; Walther, Lisa; Jones, Joseph; Lewis, Douglas; Jones, Mary

    2011-01-01

    Objective The rate of failed interlock blood alcohol concentration (BAC) tests is a strong predictor of recidivism post-interlock and a partial proxy for alcohol use. Alcohol biomarkers measured at the start of an interlock program are known to correlate well with rates of failed BAC tests over months of interlock use. This study evaluates two methods of measuring low blood levels of the biomarker PEth (phosphatidylethanol). PEth is a 100% alcohol specific biomarker and strongly intercorrelated with several independent indicators of drinking driving risk, including 8 other biomarkers, 3 psychometric assessments, and the rate of failed interlock BAC tests during many months of interlock use. Does a more sensitive method of measuring PEth at program entry detect drinking even among those who subsequently log no failed interlock tests? Methods In a sample of 281 driver blood samples, PEth was measured by both high-performance liquid chromatography (HPLC) and liquid chromatography tandem mass spectrometry (LCMSMS) in order to compare sensitivity and accuracy. The average rate of failed interlock BAC tests was the criterion measure for marker sensitivity. LCMSMS, calibrated to detect low levels of drinking as a possible measure of abstinence violation, was judged relative to the standard HPLC assay for PEth measured up to 4 µmol/L. Results The two methods showed a good quantitative relationship (r2>.86). LCMSMS detected positive PEth levels in samples that were below the limit of detection of the HPLC method. PEth measured by LCMSMS was positive for a higher proportion of DUI offenders who logged zero failed interlock BAC tests than were detected by HPLC. Conclusion Although HPLC is the widely used standard for measuring PEth in clinical alcoholism samples, the LCMSMS method, when calibrated to detect trace amounts of the major component of PEth, can detect abstinence levels of alcohol near zero intake and still correlate strongly with other indicators related to

  20. Arc Detection and Interlock Module for the PEP II Low Level RF System

    SciTech Connect

    Tighe, R.; /SLAC

    2011-08-31

    A new arc detection and interlock generating module for the SLAC PEP-II low-level RF VXI-based system has been developed. The system is required to turn off the RF drive and high voltage power supply in the event of arcing in the cavity windows, klystron window, or circulator. Infrared photodiodes receive arc signals through radiation resistant optical fibers. Gain and bandwidth are selectable for each channel to allow tailoring response. The module also responds to interlock requests from other modules in the VXI system and communicates with the programmable logic controller (PLC) responsible for much of the low-level RF system's interlock functionality.

  1. Communities detection as a tool to assess a reform of the Italian interlocking directorship network

    NASA Astrophysics Data System (ADS)

    Drago, Carlo; Ricciuti, Roberto

    2017-01-01

    Interlocking directorships are important communication channels among companies and may have anticompetitive effect. A corporate governance reform was introduced in 2011 to prevent interlocking directorships in the financial sector. We apply community detection techniques to the analysis of the networks in 2009 and 2012 to ascertain the effect of such reform on the Italian directorship network. We find that, although the number of interlocking directorships decreases in 2012, the reduction takes place mainly at the periphery of the network. The network core is stable, allowing the most connected companies to keep their strategic position.

  2. Feasibility of detecting orthopaedic screw overtightening using acoustic emission.

    PubMed

    Pullin, Rhys; Wright, Bryan J; Kapur, Richard; McCrory, John P; Pearson, Matthew; Evans, Sam L; Crivelli, Davide

    2017-03-01

    A preliminary study of acoustic emission during orthopaedic screw fixation was performed using polyurethane foam as the bone-simulating material. Three sets of screws, a dynamic hip screw, a small fragment screw and a large fragment screw, were investigated, monitoring acoustic-emission activity during the screw tightening. In some specimens, screws were deliberately overtightened in order to investigate the feasibility of detecting the stripping torque in advance. One set of data was supported by load cell measurements to directly measure the axial load through the screw. Data showed that acoustic emission can give good indications of impending screw stripping; such indications are not available to the surgeon at the current state of the art using traditional torque measuring devices, and current practice relies on the surgeon's experience alone. The results suggest that acoustic emission may have the potential to prevent screw overtightening and bone tissue damage, eliminating one of the commonest sources of human error in such scenarios.

  3. Fixed-angle screws vs standard screws in acetabular prosthesis fixation: a cadaveric biomechanical study.

    PubMed

    Hugate, Ronald R; Dickey, Ian D; Chen, Qingshan; Wood, Christina M; Sim, Franklin H; Rock, Michael G

    2009-08-01

    Secure fixation of acetabular components in total hip arthroplasty can be challenging. The purpose of this study was to perform biomechanical analysis of cup fixation strength using fixed-angle vs standard screw fixation. Multihole, porous-backed acetabular prostheses were implanted in both acetabuli of 8 cadaveric pelves using standard press-fit techniques. Fixed-angle screws were used on the left side, and standard cancellous screws were used in the right. The use of fixed-angle screws enhanced acetabular fixation substantially under subfailure cyclic loading conditions and load-to-failure. The triradiate screw configuration increases the bending moment required to fail the specimens as well. Fixed-angle screws may be useful for achieving rigid fixation of acetabular prostheses in challenging clinical scenarios.

  4. Screw-released roller brake

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1999-01-01

    A screw-released roller brake including an input drive assembly, an output drive assembly, a plurality of locking sprags, a mechanical tripper nut for unlocking the sprags, and a casing therefor. The sprags consist of three dimensional (3-D) sprag members having pairs of contact surface regions which engage respective pairs of contact surface regions included in angular grooves or slots formed in the casing and the output drive assembly. The sprags operate to lock the output drive assembly to the casing to prevent rotation thereof in an idle mode of operation. In a drive mode of operation, the tripper is either self actuated or motor driven and is translated linearly up and down against a spline and at the limit of its travel rotates the sprags which unlock while coupling the input drive assembly to the output drive assembly so as to impart a turning motion thereto in either a clockwise or counterclockwise direction.

  5. Vertical-Screw-Auger Conveyer Feeder

    NASA Technical Reports Server (NTRS)

    Walton, Otis (Inventor); Vollmer, Hubert J. (Inventor)

    2016-01-01

    A conical feeder is attached to a vertically conveying screw auger. The feeder is equipped with scoops and rotated from the surface to force-feed regolith the auger. Additional scoops are possible by adding a cylindrical section above the conical funnel section. Such then allows the unit to collect material from swaths larger in diameter than the enclosing casing pipe of the screw auger. A third element includes a flexible screw auger. All three can be used in combination in microgravity and zero atmosphere environments to drill and recover a wide area of subsurface regolith and entrained volatiles through a single access point on the surface.

  6. Effect of Off-Axis Screw Insertion, Insertion Torque, and Plate Contouring on Locked Screw Strength

    PubMed Central

    Gallagher, Bethany; Silva, Matthew J.; Ricci, William M.

    2015-01-01

    Objectives This study quantifies the effects of insertion torque, off-axis screw angulation, and plate contouring on the strength of locking plate constructs. Methods Groups of locking screws (n = 6–11 screws) were inserted at 50%, 100%, 150%, and 200% of the manufacturer-recommended torque (3.2 Nm) into locking compression plates at various angles: orthogonal (control), 5-degree angle off-axis, and 10-degree angle off-axis. Screws were loaded to failure by a transverse force (parallel to the plate) either in the same (“+”) or opposite direction (“−”) of the initial screw angulation. Separately, locking plates were bent to 5 and 10-degree angles, with the bend apex at a screw hole. Locking screws inserted orthogonally into the apex hole at 100% torque were loaded to failure. Results Orthogonal insertion resulted in the highest average load to failure, 2577 ± 141 N (range, 2413–2778 N), whereas any off-axis insertion significantly weakened constructs (165–1285 N, at 100% torque) (P < 0.05). For “+” loading, torque beyond 100% did not increase strength, but 50% torque reduced screw strength (P < 0.05). Loading in the “−” direction consistently resulted in higher strengths than “+” loading (P < 0.05). Plate contouring of 5-degree angle did not significantly change screw strength compared with straight plates but contouring of 10-degree angle significantly reduced load to failure (P < 0.05). Conclusions To maximize the screw plate interface strength, locking screws should be inserted without cross-threading. The mechanical stability of locked screws is significantly compromised by loose insertion, off-axis insertion, or severe distortion of the locking mechanism. PMID:24343255

  7. CAMAC-based interlock system for power-supply-hardware protection on MFTF

    SciTech Connect

    Strauch, M.S.

    1981-09-30

    This interlock module accepts 16 inputs and generates, in conjunction with an internal PROM map, 8 outputs. This decision process is autonomous of the CAMAC dataway and host computer. The map is generated, burned and verified by a user interactive program written to accept input/output equations in Boolean algebra. The interlock module requires the host computer to periodically interrogate it to verify proper operation of the module, host computer and date link; otherwise, permissives are dropped. An internal mask register may be used to override interlock inputs. This mask is perishable and must be constantly refreshed. Output drivers may be operated in a latch/no latch mode. This prevents outputs, once dropped, from being reasserted even if the proper input sequence is reestablished. A first-out register may be utilized to determine which input has dropped first in the event that chain reactions are developed among the interlock inputs.

  8. 18 CFR 45.9 - Automatic authorization of certain interlocking positions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... owned, wholly or in part, by the other and, as its primary business, owns or operates transmission or... interlock involves affiliated public utilities. (b) Conditions of authorization. As a condition...

  9. Cloning Nacre's 3D Interlocking Skeleton in Engineering Composites to Achieve Exceptional Mechanical Properties.

    PubMed

    Zhao, Hewei; Yue, Yonghai; Guo, Lin; Wu, Juntao; Zhang, Youwei; Li, Xiaodong; Mao, Shengcheng; Han, Xiaodong

    2016-07-01

    Ceramic/polymer composite equipped with 3D interlocking skeleton (3D IL) is developed through a simple freeze-casting method, exhibiting exceptionally light weight, high strength, toughness, and shock resistance. Long-range crack energy dissipation enabled by 3D interlocking structure is considered as the primary reinforcing mechanism for such superior properties. The smart composite design strategy should hold a place in developing future structural engineering materials.

  10. Global ice-sheet system interlocked by sea level

    NASA Astrophysics Data System (ADS)

    Denton, George H.; Hughes, Terence J.; Karlén, Wibjörn

    1986-07-01

    Denton and Hughes (1983, Quaternary Research20, 125-144) postulated that sea level linked a global ice-sheet system with both terrestrial and grounded marine components during late Quaternary ice ages. Summer temperature changes near Northern Hemisphere melting margins initiated sea-level fluctuations that controlled marine components in both polar hemispheres. It was further proposed that variations of this ice-sheet system amplified and transmitted Milankovitch summer half-year insolation changes between 45 and 75°N into global climatic changes. New tests of this hypothesis implicate sea level as a major control of the areal extent of grounded portions of the Antarctic Ice Sheet, thus fitting the concept of a globally interlocked ice-sheet system. But recent atmospheric modeling results ( Manabe and Broccoli, 1985, Journal of Geophysical Research90, 2167-2190) suggest that factors other than areal changes of the grounded Antarctic Ice Sheet strongly influenced Southern Hemisphere climate and terminated the last ice age simultaneously in both polar hemispheres. Atmospheric carbon dioxide linked to high-latitude oceans is the most likely candidate ( Shackleton and Pisias, 1985, Atmospheric carbon dioxide, orbital forcing, and climate. In "The Carbon Cycle and Atmospheric CO 2: Natural Variations Archean to Present" (E. T. Sundquest and W. S. Broecker, Eds.), pp. 303-318. Geophysical Monograph 32, American Geophysical Union, Washington, D.C.), but another potential influence was high-frequency climatic oscillations (2500 yr). It is postulated that variations in atmospheric carbon dioxide acted through an Antarctic ice shelf linked to the grounded ice sheet to produce and terminate Southern Hemisphere ice-age climate. It is further postulated that Milankovitch summer insolation combined with a warm high-frequency oscillation caused marked recession of Northern Hemisphere ice-sheet melting margins and the North Atlantic polar front about 14,000 14C yr B.P. This

  11. Requiring suspended drunk drivers to install alcohol interlocks to reinstate their licenses: effective?

    PubMed Central

    Voas, Robert B.; Tippetts, S. Scott; Fisher, Deborah; Grosz, Milton

    2015-01-01

    Aims To evaluate a new method being used by some states for motivating interlock installation by requiring it as a prerequisite to reinstatement of the driver’s license. Design The driving records of Florida DWI offenders convicted between July 2002 and June 2008 were analyzed to determine the proportion of offenders subject to the interlock requirement who installed interlocks. Setting Most driving-while-impaired (DWI) offenders succeed in avoiding state laws requiring the installation of a vehicle alcohol interlock. Participants A total of 82 318 Florida DWI offenders. Findings Due to long periods of complete suspension when no driving was permitted and the failure to complete all the requirements imposed by the court, only 21 377 of the 82 318 offenders studied qualified for reinstatement, but 93% of those who qualified did install interlocks to be reinstated. Conclusions Because of the lengthy license suspensions and other barriers that the offenders face in qualifying for reinstatement, it is not clear that requiring a period on the interlock as a prerequisite to reinstating will greatly increase the current installment rate. PMID:20528811

  12. Evaluation of a program to motivate impaired driving offenders to install ignition interlocks.

    PubMed

    Voas, Robert B; Blackman, Kenneth O; Tippetts, A Scott; Marques, Paul R

    2002-07-01

    Approximately 30,000 alcohol ignition interlocks, which are designed to prevent the operation of a vehicle if the driver has been drinking, are in use in the US and Canada. Ignition interlock programs are also being initiated in Sweden and Australia. The best-controlled studies that are currently available suggest that ignition interlocks are effective in reducing impaired driving recidivism while on the vehicle. However, in the US, the practical effectiveness of these devices is limited because only a small number of offenders are willing to install them in order to drive legally. This paper reports on a study of a court policy that created a strong incentive for impaired driving offenders to install interlocks by making traditional penalties, such as jail or electronically monitored house arrest, the alternative to participation in an interlock program. Comparison of the recidivism rates of offenders subject to this policy with offenders in similar, nearby courts, not using interlocks, indicated that the policy was producing substantial reductions in DUI recidivism.

  13. Mediastinal migration of distal occipito-thoracic instrumentation

    PubMed Central

    Joseph, Vivek; Al Jahwari, Ahmed S.

    2007-01-01

    We present the occurrence and management of mediastinal migration of the distal aspect of a posterior occipito-thoracic screw–rod construct. No similar occurrence was found in the literature. This event occurred following an emergency tracheotomy (requiring neck hyperextension) in a patient with severe rheumatoid arthritis, who had previously undergone decompression and an Occiput-T2 instrumented fusion for cranio-cervical and sub-axial cervical spine instability. Imaging showed fracture-subluxation of T1/2 and T2/3 with the bilateral C7, T1 and T2 screws in the mediastinum causing tracheal and esophageal compression. Removal of the instrumentation, decompression (T2 corpectomy) and construct revision down to T10 was safely performed from a posterior approach. Severe osteoporosis, some pre-existing screw loosening and hyperextension of the neck were the predisposing factors of this near catastrophic event. By staying directly posterior to the rod and following the fibrous tract already created, the instrumentation was safely removed from the mediastinum. PMID:18000689

  14. Additional Drive Circuitry for Piezoelectric Screw Motors

    NASA Technical Reports Server (NTRS)

    Smythe, Robert; Palmer, Dean; Gursel, Yekta; Reder, Leonard; Savedra, Raymond

    2004-01-01

    Modules of additional drive circuitry have been developed to enhance the functionality of a family of commercially available positioning motors (Picomotor . or equivalent) that provide linear motion controllable, in principle, to within increments .30 nm. A motor of this type includes a piezoelectric actuator that turns a screw. Unlike traditional piezoelectrically actuated mechanisms, a motor of this type does not rely on the piezoelectric transducer to hold position: the screw does not turn except when the drive signal is applied to the actuator.

  15. Helical rotary screw expander power system

    NASA Technical Reports Server (NTRS)

    Mckay, R. A.; Sprankle, R. S.

    1974-01-01

    An energy converter for the development of wet steam geothermal fields is described. A project to evaluate and characterize a helical rotary screw expander for geothermal applications is discussed. The helical screw expander is a positive displacement machine which can accept untreated corrosive mineralized water of any quality from a geothermal well. The subjects of corrosion, mineral deposition, the expansion process, and experience with prototype devices are reported.

  16. Interlocked DNA nanostructures controlled by a reversible logic circuit

    PubMed Central

    Li, Tao; Lohmann, Finn; Famulok, Michael

    2014-01-01

    DNA nanostructures constitute attractive devices for logic computing and nanomechanics. An emerging interest is to integrate these two fields and devise intelligent DNA nanorobots. Here we report a reversible logic circuit built on the programmable assembly of a double-stranded (ds) DNA [3]pseudocatenane that serves as a rigid scaffold to position two separate branched-out head-motifs, a bimolecular i-motif and a G-quadruplex. The G-quadruplex only forms when preceded by the assembly of the i-motif. The formation of the latter, in turn, requires acidic pH and unhindered mobility of the head-motif containing dsDNA nanorings with respect to the central ring to which they are interlocked, triggered by release oligodeoxynucleotides. We employ these features to convert the structural changes into Boolean operations with fluorescence labelling. The nanostructure behaves as a reversible logic circuit consisting of tandem YES and AND gates. Such reversible logic circuits integrated into functional nanodevices may guide future intelligent DNA nanorobots to manipulate cascade reactions in biological systems. PMID:25229207

  17. ACIS design compliance with principle accelerator safety interlock design requirements.

    SciTech Connect

    Knott, M.

    2005-02-23

    Prior to and during the design of the APS's Access Control Interlock System (ACIS), an effort was made to insure that the design complied with the relevant DOE and ANL requirements as well as those set forth in other recognized documents then in circulation. A paragraph-by-paragraph listing of the requirements (in some cases, recommended practices) and the corresponding ACIS design features was compiled for use by the review committees then in place. This tabulation was incorporated in the APS Safety Analysis Document (SAD) as Appendix A. With the evolutionary changes that have occurred to the APS and to the documents referenced, some of the details of these compliances have evolved as well. It has been decided to maintain the SAD as a ''living'' document, editing it in close time proximity to the evolving APS. Since Appendix A depicted the ACIS's original design compliance to an also-evolving set of documents, it was decided to remove Appendix A but to retain it as a reference document. This LS Note now contains that set of original design compliances. As the APS and the ACIS continue to evolve, the changes made will be subject to internal review and approval and will always be subject to the requirements set forth by the DOE and ANL.

  18. Organometallic rotaxane dendrimers with fourth-generation mechanically interlocked branches

    PubMed Central

    Wang, Wei; Chen, Li-Jun; Wang, Xu-Qing; Sun, Bin; Li, Xiaopeng; Zhang, Yanyan; Shi, Jiameng; Yu, Yihua; Zhang, Li; Liu, Minghua; Yang, Hai-Bo

    2015-01-01

    Mechanically interlocked molecules, such as catenanes, rotaxanes, and knots, have applications in information storage, switching devices, and chemical catalysis. Rotaxanes are dumbbell-shaped molecules that are threaded through a large ring, and the relative motion of the two components along each other can respond to external stimuli. Multiple rotaxane units can amplify responsiveness, and repetitively branched molecules—dendrimers—can serve as vehicles for assembly of many rotaxanes on single, monodisperse compounds. Here, we report the synthesis of higher-generation rotaxane dendrimers by a divergent approach. Linkages were introduced as spacer elements to reduce crowding and to facilitate rotaxane motion, even at the congested periphery of the compounds up to the fourth generation. The structures were characterized by 1D multinuclear (1H, 13C, and 31P) and 2D NMR spectroscopy, MALDI-TOF-MS, gel permeation chromatography (GPC), and microscopy-based methods including atomic force microscopy (AFM) and transmission electron microscopy (TEM). AFM and TEM studies of rotaxane dendrimers vs. model dendrimers show that the rotaxane units enhance the rigidity and reduce the tendency of these assemblies to collapse by self-folding. Surface functionalization of the dendrimers with ferrocenes as termini produced electrochemically active assemblies. The preparation of dendrimers with a well-defined topological structure, enhanced rigidity, and diverse functional groups opens previously unidentified avenues for the application of these materials in molecular electronics and materials science. PMID:25902491

  19. Interlocking mats support drilling rig on frozen swamp

    SciTech Connect

    Not Available

    1991-04-15

    This paper discusses how a company employed a unique mat system to reduce environmental impact and to support the drilling rig on its Astosch No. 1 exploratory well at Granite Point in the Trading Bay Wildlife Refuge. The site is on the west side of Cook Inlet. During winter, the travel time from Anchorage to the base camp near the Tyonek Indian village was 5 hr by ice road or 45 min by fixed wing aircraft. Eighteen miles of existing gravel roads were used from this base camp to the edge of the frozen muskeg swamp, and from there, they constructed 7 miles of ice road to the well site. They constructed a snow and ice pad with two impermeable liners and then installed Uni-Mat International Inc.'s patented interlocking mats for the final foundation. After moving in the rig, a snow berm was built around the perimeter of the location and an impermeable liner was then draped and secured over the berm.

  20. Ball Screw Actuator Including a Stop with an Integral Guide

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Perek, John (Inventor); Geck, Kellan (Inventor)

    2015-01-01

    An actuator includes a housing assembly, a ball nut, a ball screw, and a ball screw stop. The ball nut is rotationally mounted in the housing assembly, is adapted to receive an input torque, and is configured, upon receipt thereof, to rotate and supply a drive force. The ball screw is mounted within the housing assembly and extends through the ball nut. The ball screw has a first end and a second end, and is coupled to receive the drive force from the ball nut. The ball screw is configured, upon receipt of the drive force, to selectively translate between a stow position and a deploy position. The ball screw stop is mounted on the ball screw to translate therewith and is configured to at selectively engage the housing assembly while the ball screw is translating, and engage the ball nut when the ball screw is in the deploy position.

  1. Nonunion of distal radius fracture and distal radioulnar joint injury: a modified Sauvé-Kapandji procedure with a cubitus proradius transposition as autograft.

    PubMed

    Villamor, Angel; Rios-Luna, Antonio; Villanueva-Martínez, Manuel; Fahandezh-Saddi, Homid

    2008-12-01

    The Sauvé-Kapandji (SK) procedure is indicated in distal radius nonunion or malunion and distal radioulnar joint (DRUJ) instability. It can also be used to treat the rheumatoid wrist with severe degenerative changes in the DRUJ. The main objective is to allow a pain-free range of movement. We present a patient with rheumatoid arthritis and distal radius nonunion who, after three operations, was treated with the SK procedure. The clinical and radiological results were excellent. A 53-year-old woman diagnosed with rheumatoid arthritis fell on her forearm at home 2 years ago. Examination at an outpatient clinic revealed a distal radius fracture classified as type V according to the Frykman classification. She had been operated three times with open reduction internal fixation using a plate, screws, and bone allograft. She came to our institution with a distal radius nonunion, positive post-traumatic ulnar variance, and ulnar nerve paresis. The range of movements was 20 degrees -10 degrees flexion-extension and 40 degrees -30 degrees pronation-supination, and she needed daily fentanyl. We performed a modified SK procedure with an autologous iliac crest bone graft and ulnar bone graft from the osteotomy area (cubitus proradius), bone morphogenetic protein, and a low profile distal radius plate. After 1 year of follow-up, the distal radius fracture has healed and the wrist is pain-free with a complete range of movement in flexion-extension and pronation-supination. The main indication for the SK procedure is post-traumatic positive ulnar variance and associated ulnocarpal impaction. The cubitus proradius bone graft transposition is an interesting technical note that makes this case a challenge for skilled orthopedic hand surgeons.

  2. Insertion Profiles of 4 Headless Compression Screws

    PubMed Central

    Hart, Adam; Harvey, Edward J.; Lefebvre, Louis-Philippe; Barthelat, Francois; Rabiei, Reza; Martineau, Paul A.

    2013-01-01

    Purpose In practice, the surgeon must rely on screw position (insertion depth) and tactile feedback from the screwdriver (insertion torque) to gauge compression. In this study, we identified the relationship between interfragmentary compression and these 2 factors. Methods The Acutrak Standard, Acutrak Mini, Synthes 3.0, and Herbert-Whipple implants were tested using a polyurethane foam scaphoid model. A specialized testing jig simultaneously measured compression force, insertion torque, and insertion depth at half-screw-turn intervals until failure occurred. Results The peak compression occurs at an insertion depth of −3.1 mm, −2.8 mm, 0.9 mm, and 1.5 mm for the Acutrak Mini, Acutrak Standard, Herbert-Whipple, and Synthes screws respectively (insertion depth is positive when the screw is proud above the bone and negative when buried). The compression and insertion torque at a depth of −2 mm were found to be 113 ± 18 N and 0.348 ± 0.052 Nm for the Acutrak Standard, 104 ± 15 N and 0.175 ± 0.008 Nm for the Acutrak Mini, 78 ± 9 N and 0.245 ± 0.006 Nm for the Herbert-Whipple, and 67 ± 2N, 0.233 ± 0.010 Nm for the Synthes headless compression screws. Conclusions All 4 screws generated a sizable amount of compression (> 60 N) over a wide range of insertion depths. The compression at the commonly recommended insertion depth of −2 mm was not significantly different between screws; thus, implant selection should not be based on compression profile alone. Conically shaped screws (Acutrak) generated their peak compression when they were fully buried in the foam whereas the shanked screws (Synthes and Herbert-Whipple) reached peak compression before they were fully inserted. Because insertion torque correlated poorly with compression, surgeons should avoid using tactile judgment of torque as a proxy for compression. Clinical relevance Knowledge of the insertion profile may improve our understanding of the implants, provide a better basis for comparing screws

  3. Intraoperative stimulation of pedicle screws: a new method for verification of screw placement.

    PubMed

    Young, W F; Morledge, D E; Martin, W; Park, K B

    1995-12-01

    Pedicular fixation of the lumbosacral spine has become a popular procedure for improving fusion rates. Even in experienced hands, it can be associated with a significant rate of screw malpositioning and potential nerve root injury. In this report, we describe a technique for improving screw localization utilizing evoked electromyography responses from direct stimulation of pedicle instrumentation.

  4. The rate of screw misplacement in segmental pedicle screw fixation in adolescent idiopathic scoliosis

    PubMed Central

    2011-01-01

    Background and purpose There are no reports in the literature on the influence of learning on the pedicle screw insertion. We studied the effect of learning on the rate of screw misplacement in patients with adolescent idiopathic scoliosis treated with segmental pedicle screw fixation. Method We retrospectively evaluated low-dose spine computed tomography of 116 consecutive patients (aged 16 (12–24) years, 94 females) who were operated during 4 periods over 2005–2009 (group 1: patients operated autumn 2005–2006; group 2: 2007; group 3: 2008; and group 4: 2009). 5 types of misplacement were recorded: medial cortical perforation, lateral cortical perforation, anterior cortical perforation of the vertebral body, endplate perforation, and perforation of the neural foramen. Reslts 2,201 pedicle screws were evaluated, with an average of 19 screws per patient. The rate of screw misplacement for the whole study was 14%. The rate of lateral and medial cortical perforation was 7% and 5%. There was an inverse correlation between the occurrence of misplacement and the patient number, i.e. the date of operation (r = –0.35; p < 0.001). The skillfulness of screw insertion improved with reduction of the rate of screw misplacement from 20% in 2005–2006 to 11% in 2009, with a breakpoint at the end of the first study period (34 patients). Interpretation We found a substantial learning curve; cumulative experience may have contributed to continued reduction of misplacement rate. PMID:21189100

  5. Distal gastrectomy versus total gastrectomy for distal gastric cancer

    PubMed Central

    Liu, Zhen; Feng, Fan; Guo, Man; Liu, Shushang; Zheng, Gaozan; Xu, Guanghui; Lian, Xiao; Fan, Daiming; Zhang, Hongwei

    2017-01-01

    Abstract Even though more than a century later, after the first case of gastrectomy has been successfully performed, the best surgical treatment for distal gastric cancer still remains controversial. Thus, the present study was designed to compare the survival impact of distal (DG) or total gastrectomy (TG) for distal gastric cancer. A total of 1262 distal gastric cancer patients were enrolled in current study including 1157 patients who underwent DG and 157 patients who underwent TG. The postoperative complications and 5-year overall survival were compared between the 2 groups. TG group presented a longer surgical time, a higher volume of intraoperative bleeding, and a larger number of excised lymph nodes (all P < 0.05) compared with the DG group. The postoperative complications were comparable (all P >0.05). The 5-year overall survival rate of DG group was significantly higher than that of TG group (67.6% vs 44.3%, P < 0.001). However, multivariate analysis showed that type of resection was not an independent prognostic factor for distal gastric cancer (P > 0.05). The factor-stratified multivariate analysis showed that only in the subgroup of Tumor-node-metastasis staging system (TNM) stage III (P = 0.049), TG was the independent prognostic factor for poor survival. In conclusion, DG was as feasible as TG; however, TG did not increase the survival rate. DG brought better long-term survival than TG in patients with TNM stage III tumor. We recommended that DG should be the optimal surgical procedure for distal gastric cancer under the premise of negative resection margin. PMID:28151896

  6. Standard Waste Box Lid Screw Removal Option Testing

    SciTech Connect

    Anast, Kurt Roy

    2016-03-11

    This report provides results from test work conducted to resolve the removal of screws securing the standard waste box (SWB) lids that hold the remediated nitrate salt (RNS) drums. The test work evaluated equipment and process alternatives for removing the 42 screws that hold the SWB lid in place. The screws were secured with a red Loctite thread locker that makes removal very difficult because the rivets that the screw threads into would slip before the screw could be freed from the rivet, making it impossible to remove the screw and therefore the SWB lid.

  7. Retrospective Comparison of Percutaneous Fixation and Volar Internal Fixation of Distal Radius Fractures

    PubMed Central

    Lozano-Calderón, Santiago A.; Doornberg, Job N.

    2007-01-01

    A change in the practice of a single surgeon provided an opportunity for retrospective comparison of comparable cohorts treated with percutaneous fixation (17 patients) or a volar plate and screws (23 patients) an average of 30 months after surgery. The final evaluation was performed according to the Gartland and Werley and Mayo rating systems and the DASH questionnaire. There were no significant differences on the average scores for the percutaneous and volar plating groups, respectively: Gartland and Werley, 4 vs 5; Mayo, 82 vs 83; and DASH score 13 for both cohorts. Motion, grip, and radiographical parameters were likewise comparable. Volar internal plate and screw fixation can achieve results comparable to percutaneous fixation techniques in the treatment of fractures of the distal radius. PMID:18780085

  8. Fixation Strength of Caudal Pedicle Screws after Posterior Lumbar Interbody Fusion with the Modified Cortical Bone Trajectory Screw Method

    PubMed Central

    Miwa, Toshitada; Yamashita, Tomoya; Kuroda, Yusuke; Ohwada, Tetsuo

    2016-01-01

    Study Design Clinical case series. Purpose In the posterior lumbar interbody fusion (PLIF) procedure in our institute, the cephalad screw trajectory follows a mediolateral and caudocephalad directed path according to the original cortical bone trajectory (CBT) method. However, the starting point of the caudal screw is at the medial border of the pedicle on an articular surface of the superior articular process, and the trajectory takes a mediolateral path parallel to the cephalad endplate. The incidence of caudal screw loosening after PLIF with this modified CBT screw method was investigated, and significant risk factors for caudal screw loosening were evaluated. Overview of Literature A biomechanical study of this modified caudal screw trajectory using the finite element method reported about a 20% increase in uniaxial yield pullout load compared with the traditional trajectory. However, there has been no clinical study concerning the fixation strength of this modified caudal screw trajectory. Methods The subjects were 193 consecutive patients who underwent single-level PLIF with modified CBT screw fixation. Caudal screw loosening was checked in computed tomography at 6 months after surgery, and screw loosening was defined as a radiolucency of 1 mm or more at the bone-screw interface. Results The incidence of caudal screw loosening after lumbosacral PLIF (46.2%) was significantly higher than that after floating PLIF (6.0%). No significant differences in sex, brand of the instruments, and diameter and length of the caudal screw were evident between patients with and without caudal screw loosening. Patients with caudal screw loosening were significantly older at the time of surgery than patients without caudal screw loosening. Conclusions Fixation strength of the caudal screw after floating PLIF with this modified CBT screw technique was sufficiently acceptable. Fixation strength after the lumbosacral procedure was not. PMID:27559442

  9. Traumatic Distal Ulnar Artery Thrombosis

    PubMed Central

    Karaarslan, Ahmet A.; Karakaşlı, Ahmet; Mayda, Aslan; Karcı, Tolga; Aycan, Hakan; Kobak, Şenol

    2014-01-01

    This paper is about a posttraumatic distal ulnar artery thrombosis case that has occurred after a single blunt trauma. The ulnar artery thrombosis because of chronic trauma is a frequent condition (hypothenar hammer syndrome) but an ulnar artery thrombosis because of a single direct blunt trauma is rare. Our patient who has been affected by a single blunt trauma to his hand and developed ulnar artery thrombosis has been treated by resection of the thrombosed ulnar artery segment. This report shows that a single blunt trauma can cause distal ulnar artery thrombosis in the hand and it can be treated merely by thrombosed segment resection in suitable cases. PMID:25276455

  10. Pedicle screw fixation combined with intermediate screw at the fracture level for treatment of thoracolumbar fractures

    PubMed Central

    Li, Kunpeng; Zhang, Wen; Liu, Dan; Xu, Hui; Geng, Wei; Luo, Dawei; Ma, Jinzhu

    2016-01-01

    Abstract Background: Use of a pedicle screw at the level of fracture, also known as an intermediate screw, has been shown to improve clinical results in managing thoracolumbar(TL) fractures, but there is a paucity of powerful evidence to support the claim. The aim of this study was to compare outcomes between pedicle screw fixation combined with intermediate screw at the fracture level and conventional pedicle screw fixation (one level above and one level below the fracture level) for thoracolumbar (TL) fractures. Methods: A meta-analysis of cohort studies was conducted between pedicle screw fixation combined with intermediate screw at the fracture level (combined screw group) and conventional pedicle screw fixation (conventional group) for the treatment of TL fractures from their inception to December 2015. An extensive search of studies was performed in PubMed, Medline, Embase, and the Cochrane library. The following outcome measures were extracted: visual analogue scale (VAS), operation time and intraoperative blood loss, Cobb angle and anterior vertebral height (AVH), and complications. Data analysis was conducted with RevMan 5.3.5. Results: From 10 relevant studies identified, 283 patients undergoing pedicle screw fixation combined with intermediate screw at the fracture level were compared with 285 conventional pedicle screw procedures. The pooled analysis showed that there was statistically significant difference in terms of postoperative Cobb angle (95% confidence interval (CI), −3.00, −0.75; P = 0.001) and AVH (95% CI, 0.04, 12.23; P = 0.05), correction loss (Cobb angle: P < 0.0001; AVH: P < 0.0001) and implant failure rate (95% CI, 0.06, 0.62; P = 0.006), and blood loss (W 95% CI, 2.22, 23.60; P = 0.02) between 2 groups. But in terms of other complications, there were no differences between 2 groups (95% CI, 0.23, 2.04; P = 0.50). No difference was found in operation time (95% CI, −5.36, 14.67; P = 0.36) and VAS scores (95% CI, −0.44, 0

  11. Twin screw wet granulation: Binder delivery.

    PubMed

    Saleh, Mohammed F; Dhenge, Ranjit M; Cartwright, James J; Hounslow, Michael J; Salman, Agba D

    2015-06-20

    The effects of three ways of binder delivery into the twin screw granulator (TSG) on the residence time, torque, properties of granules (size, shape, strength) and binder distribution were studied. The binder distribution was visualised through the transparent barrel using high speed imaging as well as quantified using offline technique. Furthermore, the effect of binder delivery and the change of screw configuration (conveying elements only and conveying elements with kneading elements) on the surface velocity of granules across the screw channel were investigated using particle image velocimetry (PIV). The binder was delivered in three ways; all solid binder incorporated with powder mixture, 50% of solid binder mixed with powder mixture and 50% mixed with water, all the solid binder dissolved in water. Incorporation of all solid binder with powder mixture resulted in the relatively longer residence time and higher torque, narrower granule size distribution, more spherical granules, weaker big-sized granules, stronger small-sized granules and better binder distribution compared to that in other two ways. The surface velocity of granules showed variation from one screw to another as a result of uneven liquid distribution as well as shown a reduction while introducing the kneading elements into the screw configuration.

  12. Treatment of Femoral Shaft Fracture with an Interlocking Humeral Nail in Older Children and Adolescents

    PubMed Central

    Park, Hoon

    2012-01-01

    Purpose Rigid interlocking nailing for femoral shaft fracture is ideal for use in adolescents in terms of stability of the fracture and convenience for the patient. However, numerous authors have reported that rigid interlocking nailing has some limitations in this age group due to the risk of complications. We evaluated the results of intramedullary nailing for femoral shaft fractures with an interlocking humeral nail in older children and adolescents. Materials and Methods We retrospectively reviewed records of patients treated with an interlocking humeral nail. Radiographs were examined for proximal femoral change and evidence of osteonecrosis. Outcomes were assessed by major or minor complications that occurred after operative treatment. Results Twenty-four femoral shaft fractures in 23 patients were enrolled. The mean age at the time of operation was 12 years and 8 months and the mean follow-up period was 21 months. Bony union was achieved in all patients without any complications related to the procedure such as infection, nonunion, malalignment and limb length discrepancy. All fractures were clinically and radiographically united within an average eight weeks. No patients developed avascular necrosis of the femoral head and coxa valga. Conclusion Intramedullary nailing through the greater trochanter using a rigid interlocking humeral nail is effective and safe for the treatment of femoral shaft fractures in older children and adolescents. PMID:22318831

  13. [Cement augmentation of pedicle screws : Pros and cons].

    PubMed

    Schnake, K J; Blattert, T R; Liljenqvist, U

    2016-09-01

    Cement augmentation of pedicle screws biomechanically increases screw purchase in the bone. However, clinical complications may occur. The pros and cons of the technique are discussed from different clinical perspectives.

  14. Impact of screw configuration on the particle size distribution of granules produced by twin screw granulation.

    PubMed

    Vercruysse, J; Burggraeve, A; Fonteyne, M; Cappuyns, P; Delaet, U; Van Assche, I; De Beer, T; Remon, J P; Vervaet, C

    2015-02-01

    Twin screw granulation (TSG) has been reported by different research groups as an attractive technology for continuous wet granulation. However, in contrast to fluidized bed granulation, granules produced via this technique typically have a wide and multimodal particle size distribution (PSD), resulting in suboptimal flow properties. The aim of the current study was to evaluate the impact of granulator screw configuration on the PSD of granules produced by TSG. Experiments were performed using a 25 mm co-rotating twin screw granulator, being part of the ConsiGma™-25 system (a fully continuous from-powder-to-tablet manufacturing line from GEA Pharma Systems). Besides the screw elements conventionally used for TSG (conveying and kneading elements), alternative designs of screw elements (tooth-mixing-elements (TME), screw mixing elements (SME) and cutters) were investigated using an α-lactose monohydrate formulation granulated with distilled water. Granulation with only conveying elements resulted in wide and multimodal PSD. Using kneading elements, the width of the PSD could be partially narrowed and the liquid distribution was more homogeneous. However, still a significant fraction of oversized agglomerates was obtained. Implementing additional kneading elements or cutters in the final section of the screw configuration was not beneficial. Furthermore, granulation with only TME or SME had limited impact on the width of the PSD. Promising results were obtained by combining kneading elements with SME, as for these configurations the PSD was narrower and shifted to the size fractions suitable for tableting.

  15. [Evaluation of surgical repair of distal biceps tendon ruptures].

    PubMed

    Behounek, J; Hrubina, M; Skoták, M; Krumpl, O; Zahálka, M; Dvorák, J; Fucík, M

    2009-02-01

    PURPOSE OF THE STUDY To present the results of surgical repair of ruptures of the distal tendon of the biceps brachii muscle and thus show the adequacy of this treatment. MATERIAL Between 1987 and 2006, 19 patients had surgery for distal biceps tendon rupture. Only one side was affected in each patient. All patients were men between 28 and 69 years (average age, 47.5 years) at the time of injury (surgery). When the patients were evaluated at the end of 2007, 18 patients were included, because one died a year after surgery. METHODS The surgical repair always included a single-incision anatomical reattachment into the radial tuberosity. In 11 patients, a modified Mac Reynolds method with screw and washer fixation was used; in seven patients the insertion was fixed with Mitek anchors and, in one, it was sutured to the adjacent soft tissues. The average follow-up was 7 years (range, 1 to 20.5 years). The patients were evaluated for the cause of injury, their physical activity, age, dominance of the injured arm, surgical procedure and complications. RESULTS In 18 patients surgical repair was done early and, in one, at 16 days after injury. In all of them the tendon was detached from its site of insertion, but never torn. The intra-operative complications included, in one patient, bleeding owing to iatrogenic damage to a branch of the brachial artery, and difficult separation of the tendon due to its previous healed injury in another patient. Early post-operative complications included superficial skin necrosis in one patient and transient neurological deficit of the dorsal brand of the radial nerve and of the lateral cutaneous nerve of the forearm in two and one patient, respectively. The late complications were heterotropic ossification in three patients and screw migration in the one treated by the Mac Reynolds method. Excellent results were recorded in 11 patients (61 %), and good outcomes with a slight restriction of motion or muscle strength not limiting the

  16. Screw expander for light duty diesel engines

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Preliminary selection and sizing of a positive displacement screw compressor-expander subsystem for a light-duty adiabatic diesel engine; development of a mathematical model to describe overall efficiencies for the screw compressor and expander; simulation of operation to establish overall efficiency for a range of design parameters and at given engine operating points; simulation to establish potential net power output at light-duty diesel operating points; analytical determination of mass moments of inertia for the rotors and inertia of the compressor-expander subsystem; and preparation of engineering layout drawings of the compressor and expander are discussed. As a result of this work, it was concluded that the screw compressor and expander designed for light-duty diesel engine applications are viable alternatives to turbo-compound systems, with acceptable efficiencies for both units, and only a moderate effect on the transient response.

  17. A modified technique for removing a failed abutment screw from an implant with a custom guide tube.

    PubMed

    Taira, Yohsuke; Sawase, Takashi

    2012-04-01

    Fracture of abutment screw is a serious prosthodontic complication. When the abutment screw is fractured at the junction of the screw shank and screw thread, removal of the fractured screw fragment from the screw hole can be difficult. This article describes a modified technique for removing the failed abutment screw with a custom guide tube and tungsten carbide bur. The failed screw can be removed speedily without damaging the screw hole of the implant body or the screw threads.

  18. [Fractures of the distal radius].

    PubMed

    Rueger, J M; Hartel, M J; Ruecker, A H; Hoffmann, M

    2014-11-01

    The most prevalent fractures managed by trauma surgeons are those involving the distal radius. The injury occurs in two peaks of prevalence: the first peak around the age of 10 years and the second peak around the age of 60 years. Distal radius fracture management requires sensitive diagnostics and classification. The objectives of treatment are the reconstruction of a pain-free unlimited durable functioning of the wrist and avoidance of typical fracture complications. Non-operative conservative management is generally employed for stable non-displaced fractures of the distal radius with the expectation of a good functional outcome. Unstable comminuted fractures with intra-articular and extra-articular fragment zones are initially set in a closed operation and finally by osteosynthesis. An armament of surgical implants is available for instable fractures requiring fixation. Palmar locked plate osteosynthesis has been established in recent years as the gold standard for operative management of distal radius fractures. Complex Working Group on Osteosynthesis (AO) classification type 3 fractures require extensive preoperative diagnostics to identify and treat typical associated injuries around the wrist.

  19. Outcome Assessment after Aptis Distal Radioulnar Joint (DRUJ) Implant Arthroplasty

    PubMed Central

    Kachooei, Amir Reza; Chase, Samantha M; Jupiter, Jesse B

    2014-01-01

    Background: Conventional treatments after complicated injuries of the distal radioulnar joint (DRUJ) such as Darrach and Kapandji-Sauvé procedures have many drawbacks, which may eventually lead to a painful unstable distal ulna. The development of DRUJ prosthesis has significantly evolved over the past years. In this study, we assessed the outcome results of patients after DRUJ implant arthroplasty using the Aptis (Scheker) prosthesis. Methods: We identified 13 patients with 14 prosthesis during the past 10 years. Patients underwent DRUJ arthroplasty due to persistent symptoms of instability, chronic pain, and stiffness. Records and follow-up visits were reviewed to find the final post-operative symptoms, pain, range of motion, and grip strength with a mean follow-up of 12 months (range: 2-25 months). Also, patients were contacted prospectively by phone in order to administer the disabilities of the arm shoulder and hand (DASH), patient rated wrist evaluation (PRWE), and visual analogue scale (VAS), and to interview regarding satisfaction and progress in daily activities. Eleven patients out of 13 could be reached with a median follow-up time of 60 months (range: 2 to 102 months). Results: No patient required removal of the prosthesis. Only two patients underwent secondary surgeries in which both required debridement of the screw tip over the radius. The median DASH score, PRWE score, VAS, and satisfaction were 1.3, 2.5, 0, and 10, respectively. The mean range of flexion, extension, supination, and pronation was 62, 54, 51, and 64, respectively. Conclusions: Distal radioulnar joint injuries are disabling and patients usually undergo one or more salvage surgeries prior to receiving an arthroplasty. The Scheker prosthesis has shown satisfactory results with 100% survival rate in all reports. The constrained design of this prosthesis gives enough stability to prevent painful subluxation. PMID:25386579

  20. Spline-Screw Multiple-Rotation Mechanism

    NASA Technical Reports Server (NTRS)

    Vranish, John M.

    1994-01-01

    Mechanism functions like combined robotic gripper and nut runner. Spline-screw multiple-rotation mechanism related to spline-screw payload-fastening system described in (GSC-13454). Incorporated as subsystem in alternative version of system. Mechanism functions like combination of robotic gripper and nut runner; provides both secure grip and rotary actuation of other parts of system. Used in system in which no need to make or break electrical connections to payload during robotic installation or removal of payload. More complicated version needed to make and break electrical connections. Mechanism mounted in payload.

  1. 21 CFR 872.4880 - Intraosseous fixation screw or wire.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Intraosseous fixation screw or wire. 872.4880... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4880 Intraosseous fixation screw or wire. (a) Identification. An intraosseous fixation screw or wire is a metal device intended to be...

  2. 21 CFR 872.4880 - Intraosseous fixation screw or wire.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Intraosseous fixation screw or wire. 872.4880... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4880 Intraosseous fixation screw or wire. (a) Identification. An intraosseous fixation screw or wire is a metal device intended to be...

  3. 21 CFR 872.4880 - Intraosseous fixation screw or wire.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Intraosseous fixation screw or wire. 872.4880... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4880 Intraosseous fixation screw or wire. (a) Identification. An intraosseous fixation screw or wire is a metal device intended to be...

  4. 21 CFR 872.4880 - Intraosseous fixation screw or wire.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraosseous fixation screw or wire. 872.4880... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4880 Intraosseous fixation screw or wire. (a) Identification. An intraosseous fixation screw or wire is a metal device intended to be...

  5. 21 CFR 872.4880 - Intraosseous fixation screw or wire.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Intraosseous fixation screw or wire. 872.4880... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4880 Intraosseous fixation screw or wire. (a) Identification. An intraosseous fixation screw or wire is a metal device intended to be...

  6. Programmable controllers replace relays in MFTF-B personnel-safety interlocks

    SciTech Connect

    Branum, J.D.

    1981-10-20

    This paper describes a new approach for implementing personnel safety interlocks logic using industrial-type programmable controllers. The logic for all personnel safety interlocks except those totally internal to a subsystem is implemented in two non-redundant controllers. A high degree of fail-safe reliability is achieved by augmenting the protective features intrinsic to each controller with those provided by a small amount of external support hardware. The controllers are interfaced to the host computer system via fiber optic data links to enable display of interlock and overall system status on the control room graphic displays. When fully implemented, the controllers will perform the equivalent of over 2000 discreet relay functions.

  7. Evaluation and application of a fast module in a PLC based interlock and control system

    NASA Astrophysics Data System (ADS)

    Zaera-Sanz, M.

    2009-08-01

    The LHC Beam Interlock system requires a controller performing a simple matrix function to collect the different beam dump requests. To satisfy the expected safety level of the Interlock, the system should be robust and reliable. The PLC is a promising candidate to fulfil both aspects but too slow to meet the expected response time which is of the order of μseconds. Siemens has introduced a ``so called'' fast module (FM352-5 Boolean Processor). It provides independent and extremely fast control of a process within a larger control system using an onboard processor, a Field Programmable Gate Array (FPGA), to execute code in parallel which results in extremely fast scan times. It is interesting to investigate its features and to evaluate it as a possible candidate for the beam interlock system. This paper publishes the results of this study. As well, this paper could be useful for other applications requiring fast processing using a PLC.

  8. Mechanical interlocking of cotton fibers on slightly textured surfaces of metallic cylinders

    NASA Astrophysics Data System (ADS)

    Zhang, Youqiang; Tian, Yu; Meng, Yonggang

    2016-05-01

    Mechanical interlocking is widely applied in industry and general lives of human beings. In this work, we realized the control of locking or sliding states of cotton fibers on the metal surfaces with slightly different textures through traditional machining. Three types of sliding states, i.e., locking, one-way sliding, and two-way sliding have been achieved. It is found that the locking or sliding of the cotton fibers on the metallic cylinder depends on the friction coefficient and the ratio of cotton fiber diameter, 2r, to the height of the rough peaks, h, of metal surfaces. When the critical ratio h/r exceeds 1, the cotton fibers could tightly attach to the metallic surface through mechanical interlocking. This work provided a convenient and universal method for the control of interlocking or sliding of fiber-based materials on textured surfaces.

  9. Tactile-direction-sensitive and stretchable electronic skins based on human-skin-inspired interlocked microstructures.

    PubMed

    Park, Jonghwa; Lee, Youngoh; Hong, Jaehyung; Lee, Youngsu; Ha, Minjeong; Jung, Youngdo; Lim, Hyuneui; Kim, Sung Youb; Ko, Hyunhyub

    2014-12-23

    Stretchable electronic skins with multidirectional force-sensing capabilities are of great importance in robotics, prosthetics, and rehabilitation devices. Inspired by the interlocked microstructures found in epidermal-dermal ridges in human skin, piezoresistive interlocked microdome arrays are employed for stress-direction-sensitive, stretchable electronic skins. Here we show that these arrays possess highly sensitive detection capability of various mechanical stimuli including normal, shear, stretching, bending, and twisting forces. Furthermore, the unique geometry of interlocked microdome arrays enables the differentiation of various mechanical stimuli because the arrays exhibit different levels of deformation depending on the direction of applied forces, thus providing different sensory output patterns. In addition, we show that the electronic skins attached on human skin in the arm and wrist areas are able to distinguish various mechanical stimuli applied in different directions and can selectively monitor different intensities and directions of air flows and vibrations.

  10. Mechanical interlocking of cotton fibers on slightly textured surfaces of metallic cylinders

    PubMed Central

    Zhang, Youqiang; Tian, Yu; Meng, Yonggang

    2016-01-01

    Mechanical interlocking is widely applied in industry and general lives of human beings. In this work, we realized the control of locking or sliding states of cotton fibers on the metal surfaces with slightly different textures through traditional machining. Three types of sliding states, i.e., locking, one-way sliding, and two-way sliding have been achieved. It is found that the locking or sliding of the cotton fibers on the metallic cylinder depends on the friction coefficient and the ratio of cotton fiber diameter, 2r, to the height of the rough peaks, h, of metal surfaces. When the critical ratio h/r exceeds 1, the cotton fibers could tightly attach to the metallic surface through mechanical interlocking. This work provided a convenient and universal method for the control of interlocking or sliding of fiber-based materials on textured surfaces. PMID:27156720

  11. Online visual inspection of self-piercing riveting to determine the quality of the mechanical interlock

    NASA Astrophysics Data System (ADS)

    Johnson, P.; Cullen, J. D.; Al-Shamma'a, A. I.; Shaw, A.

    2007-07-01

    Self-piercing riveting (SPR) has become a significant joining technique for the automotive applications of aluminium sheets. Quality control in this locale has progressed at an altogether more leisurely rate than other areas of mechanical joining (e.g. spotweld) and is underdeveloped. Testing the quality mechanical interlock is often achieved by destructive testing, which results in material and time wastage. The solution is online monitoring of the self-piercing riveting process to provide non-destructive testing of the mechanical interlock. Introducing sensors into the process facilitates real time data acquisition, which can be used to determine the quality of the joint.

  12. Joining mechanism with stem tension and interlocked compression ring

    DOEpatents

    James, Allister W.; Morrison, Jay A.

    2012-09-04

    A stem (34) extends from a second part (30) through a hole (28) in a first part (22). A groove (38) around the stem provides a non-threaded contact surface (42) for a ring element (44) around the stem. The ring element exerts an inward force against the non-threaded contact surface at an angle that creates axial tension (T) in the stem, pulling the second part against the first part. The ring element is formed of a material that shrinks relative to the stem by sintering. The ring element may include a split collet (44C) that fits partly into the groove, and a compression ring (44E) around the collet. The non-threaded contact surface and a mating distal surface (48) of the ring element may have conic geometries (64). After shrinkage, the ring element is locked onto the stem.

  13. A shape-persistent quadruply interlocked giant cage catenane with two distinct pores in the solid state.

    PubMed

    Zhang, Gang; Presly, Oliver; White, Fraser; Oppel, Iris M; Mastalerz, Michael

    2014-05-12

    Discrete interlocked three-dimensional structures are synthetic targets that are sometimes difficult to obtain with "classical" synthetic approaches, and dynamic covalent chemistry has been shown to be a useful method to form such interlocked structures as thermodynamically stable products. Although interlocked and defined hollow structures are found in nature, for example, in some viruses, similar structures have rarely been synthesized on a molecular level. Shape-persistent interlocked organic cage compounds with dimensions in the nanometer regime are now accessible in high yields during crystallization through the formation of 96 covalent bonds. The interlocked molecules form an unprecedented porous material with intrinsic and extrinsic pores both in the micropore and mesopore regime.

  14. Improvements to the single screw extruder

    NASA Technical Reports Server (NTRS)

    Hiemenz, C.; Ziegmann, G.; Franzkoch, B.; Hoffmanns, W.; Michaeli, W.

    1977-01-01

    The extrusion on a single screw extruder is examined. The process is divided into several steps: the dosage of the materials to be conveyed; the modification of the shape of the feeding opening which influences the feeding process and consequently the throughput of the extruder; optimizing the shape of the feeding zone to meet the specific material requirements; and plasticizing and homogenizing.

  15. Nylon screws make inexpensive coil forms

    NASA Technical Reports Server (NTRS)

    Aucoin, G.; Rosenthal, C.

    1978-01-01

    Standard nylon screws act as coil form copper wire laid down in spiral thread. Completed coil may be bonded to printed-circuit board. However, it is impossible to tune coil by adjusting spacing between windings, technique sometimes used with air-core coils.

  16. Improvements In Ball-Screw Linear Actuators

    NASA Technical Reports Server (NTRS)

    Iskenderian, Theodore; Joffe, Benjamin; Summers, Robert

    1996-01-01

    Report describes modifications of design of type of ball-screw linear actuator driven by dc motor, with linear-displacement feedback via linear variable-differential transformer (LVDT). Actuators used to position spacecraft engines to direct thrust. Modifications directed toward ensuring reliable and predictable operation during planned 12-year cruise and interval of hard use at end of cruise.

  17. [Distal radius fractures in children].

    PubMed

    Otayek, S; Ramanoudjame, M; Fitoussi, F

    2016-12-01

    Metaphyseal and physeal fractures of the distal radius are common in children. Most cases are best treated with closed reduction and cast immobilization. Long-term outcomes of these injuries are excellent when specific treatment principles of reduction and casting are followed. Surgical indications are limited and include open fractures, intra-articular fractures, non-reducible fractures, unstable fractures, and the presence of associated nerve injury. Closed reduction and percutaneous pin fixation is the most commonly used surgical option. The clinician should be aware of delayed complications such as growth disturbance of the distal radius, and understand how to manage these problems to ensure successful long-term outcomes. Epiphysiodesis is uncommon but growth plate injuries need to be followed for one year.

  18. Distal clavicle fractures in children☆

    PubMed Central

    Labronici, Pedro José; da Silva, Ricardo Rodrigues; Franco, Marcos Vinícius Viana; Labronici, Gustavo José; Pires, Robinson Esteves Santos; Franco, José Sergio

    2015-01-01

    Objective To analyze fractures of the distal clavicle region in pediatric patients. Methods Ten patients between the ages of five to eleven years (mean of 7.3 years) were observed. Nine patients were treated conservatively and one surgically. All the fractures were classified using the Nenopoulos classification system. Results All the fractures consolidated without complications. Conservative treatment was used for nine patients, of whom three were in group IIIB, three IIb, two IIa and one IV. The only patient who was treated surgically was a female patient of eleven years of age with a group IV fracture. Conclusion The treatment indication for distal fractures of the clavicle in children should be based on the patient's age and the displacement of the fragments. PMID:26962489

  19. Distal esophageal spasm: an update.

    PubMed

    Achem, Sami R; Gerson, Lauren B

    2013-09-01

    Distal esophageal spasm (DES) is an esophageal motility disorder that presents clinically with chest pain and/or dysphagia and is defined manometrically as simultaneous contractions in the distal (smooth muscle) esophagus in ≥20% of wet swallows (and amplitude contraction of ≥30 mmHg) alternating with normal peristalsis. With the introduction of high resolution esophageal pressure topography (EPT) in 2000, the definition of DES was modified. The Chicago classification proposed that the defining criteria for DES using EPT should be the presence of at least two premature contractions (distal latency<4.5 s) in a context of normal EGJ relaxation. The etiology of DES remains insufficiently understood, but evidence links nitric oxide (NO) deficiency as a culprit resulting in a disordered neural inhibition. GERD frequently coexists in DES, and its role in the pathogenesis of symptoms needs further evaluation. There is some evidence from small series that DES can progress to achalasia. Treatment remains challenging due in part to lack of randomized placebo-controlled trials. Current treatment agents include nitrates (both short and long acting), calcium-channel blockers, anticholinergic agents, 5-phosphodiesterase inhibitors, visceral analgesics (tricyclic agents or SSRI), and esophageal dilation. Acid suppression therapy is frequently used, but clinical outcome trials to support this approach are not available. Injection of botulinum toxin in the distal esophagus may be effective, but further data regarding the development of post-injection gastroesophageal reflux need to be assessed. Heller myotomy combined with fundoplication remains an alternative for the rare refractory patient. Preliminary studies suggest that the newly developed endoscopic technique of per oral endoscopic myotomy (POEM) may also be an alternative treatment modality.

  20. Endoscopic Distal Tibiofibular Syndesmosis Arthrodesis.

    PubMed

    Lui, Tun Hing

    2016-04-01

    Chronic distal tibiofibular syndesmosis disruption can be managed by endoscopic arthrodesis of the syndesmosis. This is performed through the proximal anterolateral and posterolateral portals. The scar tissue and bone block are resected to facilitate the subsequent reduction of the syndesmosis. The reduction of the syndesmosis can be guided either arthroscopically or endoscopically. The tibial and fibular surfaces of the tibiofibular overlap can be microfractured to facilitate subsequent fusion.

  1. Initial strength of highpressed extrusion poly-L-lactide screw.

    PubMed

    Matsushita, T; Nakamura, K; Shiro, R; Takazawa, H; Tsuji, K; Kurokawa, T

    2000-01-01

    We developed a poly-L-lactide material strengthened by a highpressed extrusion technique. The bending strength of a rod made of that material is higher than that of the same size rods made of poly-L-lactide strengthened by drawing technique, which has been used in clinical cases. The purposes of this study were, first to clarify if the initial strength of extrusion-strengthened poly-L-lactide screws is higher than that of draw-strengthened poly-L-lactide screws, and, secondly to investigate the safe torque for driving the screws in clinical usage. In accordance with AO screw design, five kinds of screws were manufactured. In a pull-out test and a twisting test using a DYRACON blocks, the strength of the highpressed extrusion-strengthened poly-L-lactide material was also higher than that of the draw-strengthened poly-L-lactide material after milling into screws. In the simulation using minipig bones and the 4.5 mm psi cortical screws, when the thickness was below 0.5 mm, between 0.5 and 2 mm or over 3 mm, the break locations were in the cortical bone, the thread of the screw and the under head fillet respectively. In the simulation using minipig bones and the 4.0 mm psi cancellous screws, breakage occurred not on the screws but on the cancellous bone in all screws.

  2. Surgical screw segmentation for mobile C-arm CT devices

    NASA Astrophysics Data System (ADS)

    Görres, Joseph; Brehler, Michael; Franke, Jochen; Wolf, Ivo; Vetter, Sven Y.; Grützner, Paul A.; Meinzer, Hans-Peter; Nabers, Diana

    2014-03-01

    Calcaneal fractures are commonly treated by open reduction and internal fixation. An anatomical reconstruction of involved joints is mandatory to prevent cartilage damage and premature arthritis. In order to avoid intraarticular screw placements, the use of mobile C-arm CT devices is required. However, for analyzing the screw placement in detail, a time-consuming human-computer interaction is necessary to navigate through 3D images and therefore to view a single screw in detail. Established interaction procedures of repeatedly positioning and rotating sectional planes are inconvenient and impede the intraoperative assessment of the screw positioning. To simplify the interaction with 3D images, we propose an automatic screw segmentation that allows for an immediate selection of relevant sectional planes. Our algorithm consists of three major steps. At first, cylindrical characteristics are determined from local gradient structures with the help of RANSAC. In a second step, a DBScan clustering algorithm is applied to group similar cylinder characteristics. Each detected cluster represents a screw, whose determined location is then refined by a cylinder-to-image registration in a third step. Our evaluation with 309 screws in 50 images shows robust and precise results. The algorithm detected 98% (303) of the screws correctly. Thirteen clusters led to falsely identified screws. The mean distance error for the screw tip was 0.8 +/- 0.8 mm and for the screw head 1.2 +/- 1 mm. The mean orientation error was 1.4 +/- 1.2 degrees.

  3. Surgeon's view of pedicle screw implantation for the monitoring neurophysiologist.

    PubMed

    Joglekar, Siddharth B; Mehbod, Amir A

    2012-12-01

    Pedicle screws have become the gold standard of spinal instrumentation over the past decade owing to their biomechanical superiority. Despite their advantages, pedicle screw instrumentation is potentially dangerous, and surgeons wish to improve accuracy of screw placement to avoid complications associated with screw misplacement. The anatomy of the pedicles is variable throughout the spine, and several landmarks and trajectories have been suggested to aid safe placement of pedicle screws in the spine. Several techniques such as x-ray and computed tomography scan imaging coupled with computer-aided navigation are available to improve accuracy of screw insertion. Intraoperative neuromonitoring with the help of triggered electromyographic recordings has evolved as an objective evidence of assessing pedicle breach and proximity of the screw to neural structures. While all imaging and electrophysiological modalities should be applied on an individualized basis, finally no adjunctive technique can fully replace the need for surgical expertise and experience.

  4. 49 CFR 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ratio, one forward drive position shall provide a greater degree of engine braking than the highest....3Starter interlock. Except as provided in S3.1.3.1 through S3.1.3.3, the engine starter shall be... driver has activated the vehicle's propulsion system: (a) The engine may stop and restart...

  5. Software Verification and Validation Test Report for the HEPA filter Differential Pressure Fan Interlock System

    SciTech Connect

    ERMI, A.M.

    2000-09-05

    The HEPA Filter Differential Pressure Fan Interlock System PLC ladder logic software was tested using a Software Verification and Validation (V&V) Test Plan as required by the ''Computer Software Quality Assurance Requirements''. The purpose of his document is to report on the results of the software qualification.

  6. Enhanced Mechanical Performance of Bio-Inspired Hybrid Structures Utilising Topological Interlocking Geometry.

    PubMed

    Djumas, Lee; Molotnikov, Andrey; Simon, George P; Estrin, Yuri

    2016-05-24

    Structural composites inspired by nacre have emerged as prime exemplars for guiding materials design of fracture-resistant, rigid hybrid materials. The intricate microstructure of nacre, which combines a hard majority phase with a small fraction of a soft phase, achieves superior mechanical properties compared to its constituents and has generated much interest. However, replicating the hierarchical microstructure of nacre is very challenging, not to mention improving it. In this article, we propose to alter the geometry of the hard building blocks by introducing the concept of topological interlocking. This design principle has previously been shown to provide an inherently brittle material with a remarkable flexural compliance. We now demonstrate that by combining the basic architecture of nacre with topological interlocking of discrete hard building blocks, hybrid materials of a new type can be produced. By adding a soft phase at the interfaces between topologically interlocked blocks in a single-build additive manufacturing process, further improvement of mechanical properties is achieved. The design of these fabricated hybrid structures has been guided by computational work elucidating the effect of various geometries. To our knowledge, this is the first reported study that combines the advantages of nacre-inspired structures with the benefits of topological interlocking.

  7. Custom sectional impression trays with interlocking type handle for microstomia patients.

    PubMed

    Fernandes, Aquaviva S; Mascarenhas, Kennedy; Aras, Meena A

    2009-01-01

    Making impressions in microstomia patients is often cumbersome. A modification of standard impression procedure is often necessary while treating such patients. This article describes the fabrication of a custom sectional impression tray with interlocking type of a handle for definitive impression procedures in a microstomia patient.

  8. Experimental Investigation About Stamping Behaviour of 3D Warp Interlock Composite Preforms

    NASA Astrophysics Data System (ADS)

    Dufour, Clément; Wang, Peng; Boussu, François; Soulat, Damien

    2014-10-01

    Forming of continuous fibre reinforcements and thermoplastic resin commingled prepregs can be performed at room temperature due to its similar textile structure. The "cool" forming stage is better controlled and more economical. The increase of temperature and the resin consolidation phases after the forming can be carried out under the isothermal condition thanks to a closed system. It can avoid the manufacturing defects easily experienced in the non-isothermal thermoforming, in particular the wrinkling [1]. Glass/Polypropylene commingled yarns have been woven inside different three-dimensional (3D) warp interlock fabrics and then formed using a double-curved shape stamping tool. The present study investigates the in-plane and through-thickness behaviour of the 3D warp interlock fibrous reinforcements during forming with a hemispherical punch. Experimental data allow analysing the forming behaviour in the warp and weft directions and on the influence of warp interlock architectures. The results point out that the layer to layer warp interlock preform has a better stamping behaviour, in particular no forming defects and good homogeneity in thickness.

  9. Enhanced Mechanical Performance of Bio-Inspired Hybrid Structures Utilising Topological Interlocking Geometry

    PubMed Central

    Djumas, Lee; Molotnikov, Andrey; Simon, George P.; Estrin, Yuri

    2016-01-01

    Structural composites inspired by nacre have emerged as prime exemplars for guiding materials design of fracture-resistant, rigid hybrid materials. The intricate microstructure of nacre, which combines a hard majority phase with a small fraction of a soft phase, achieves superior mechanical properties compared to its constituents and has generated much interest. However, replicating the hierarchical microstructure of nacre is very challenging, not to mention improving it. In this article, we propose to alter the geometry of the hard building blocks by introducing the concept of topological interlocking. This design principle has previously been shown to provide an inherently brittle material with a remarkable flexural compliance. We now demonstrate that by combining the basic architecture of nacre with topological interlocking of discrete hard building blocks, hybrid materials of a new type can be produced. By adding a soft phase at the interfaces between topologically interlocked blocks in a single-build additive manufacturing process, further improvement of mechanical properties is achieved. The design of these fabricated hybrid structures has been guided by computational work elucidating the effect of various geometries. To our knowledge, this is the first reported study that combines the advantages of nacre-inspired structures with the benefits of topological interlocking. PMID:27216277

  10. 18 CFR 131.31 - FERC Form No. 561, Annual report of interlocking positions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false FERC Form No. 561, Annual report of interlocking positions. 131.31 Section 131.31 Conservation of Power and Water Resources... regulations: enter in space 4 the complete FERC docket number of such authorization; enter in space 5...

  11. 78 FR 26849 - Model Specifications for Breath Alcohol Ignition Interlock Devices (BAIIDs)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-08

    ...This notice revises the Model Specifications for Breath Alcohol Ignition Interlock Devices (BAIIDs). The Model Specifications are guidelines for the performance and uniform testing of BAIIDs. These devices are designed to prevent a driver from starting a motor vehicle when the driver's breath alcohol concentration (BrAC) is at or above a set alcohol level. Every State in the United States has......

  12. Control and Interlocking System for Bending Magnet Front-end at Indus-2

    NASA Astrophysics Data System (ADS)

    Kane, Sanjeev R.; Garg, Chander Kant; Nandedkar, R. V.

    2007-01-01

    We present control and interlock system developed for Indus-2 bending magnet front-end. The paper describes in detail the control of various signals associated with the front-end and the interlocking scheme implemented for the installed front-end. The number of signals associated with each front-end is ˜ 75. A control system is designed for monitoring temperature, pressure, airflow, water flow and control of vacuum gauges, fast shutter, water cooled shutter, safety shutter, pneumatic gate valves, sputter ion pump power supplies, beam position monitor etc. Two independent signals are generated for critical components that are used for software interlock and hard-wired interlock. The front-end control system is VME based and window 2000/XP workstation as an operator console. The CPU used is Motorola 68000-processor board of the VME bus having OS-9 real time operating system. One VME crate serves a cluster of 2-3 front ends. The communication between the VME and the workstation is linked over RS232 serial communication. The sputter ion power supplies are connected over isolated RS485 network. Critical protection features are implemented so that no single failure can render the system unsafe. This is implemented by providing two independent chains of protection (1) Hard wired in which relay logic is used and (2) Software. A Graphical User Interface (GUI) is developed using Lab view Version 7.0.

  13. 49 CFR 236.476 - Interlocking inspections and tests applicable to traffic control systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... traffic control systems. 236.476 Section 236.476 Transportation Other Regulations Relating to... SYSTEMS, DEVICES, AND APPLIANCES Traffic Control Systems Inspection and Tests § 236.476 Interlocking inspections and tests applicable to traffic control systems. The inspections and tests prescribed in §§...

  14. 49 CFR 236.476 - Interlocking inspections and tests applicable to traffic control systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... traffic control systems. 236.476 Section 236.476 Transportation Other Regulations Relating to... SYSTEMS, DEVICES, AND APPLIANCES Traffic Control Systems Inspection and Tests § 236.476 Interlocking inspections and tests applicable to traffic control systems. The inspections and tests prescribed in §§...

  15. 49 CFR 236.426 - Interlocking rules and instructions applicable to traffic control systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... traffic control systems. 236.426 Section 236.426 Transportation Other Regulations Relating to... SYSTEMS, DEVICES, AND APPLIANCES Traffic Control Systems Rules and Instructions § 236.426 Interlocking rules and instructions applicable to traffic control systems. The rules and instructions prescribed...

  16. 49 CFR 236.426 - Interlocking rules and instructions applicable to traffic control systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... traffic control systems. 236.426 Section 236.426 Transportation Other Regulations Relating to... SYSTEMS, DEVICES, AND APPLIANCES Traffic Control Systems Rules and Instructions § 236.426 Interlocking rules and instructions applicable to traffic control systems. The rules and instructions prescribed...

  17. 18 CFR 131.31 - FERC Form No. 561, Annual report of interlocking positions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... INTERLOCKING POSITIONS GENERAL INFORMATION: Purpose of Report The data collected by this report will be used by... Comments on Public Reporting Burden The public reporting burden for this collection of information is... existing data sources, gathering and maintaining the data needed, and completing and reviewing...

  18. 18 CFR 131.31 - FERC Form No. 561, Annual report of interlocking positions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY APPROVED FORMS, FEDERAL POWER ACT AND PUBLIC UTILITY REGULATORY POLICIES ACT OF 1978 FORMS § 131.31 FERC Form No. 561, Annual report of interlocking... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false FERC Form No....

  19. 18 CFR 131.31 - FERC Form No. 561, Annual report of interlocking positions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY APPROVED FORMS, FEDERAL POWER ACT AND PUBLIC UTILITY REGULATORY POLICIES ACT OF 1978 FORMS § 131.31 FERC Form No. 561, Annual report of interlocking... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false FERC Form No....

  20. 18 CFR 131.31 - FERC Form No. 561, Annual report of interlocking positions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY APPROVED FORMS, FEDERAL POWER ACT AND PUBLIC UTILITY REGULATORY POLICIES ACT OF 1978 FORMS § 131.31 FERC Form No. 561, Annual report of interlocking... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false FERC Form No....

  1. 49 CFR 1242.58 - Operating signals and interlockers, operating drawbridges, highway crossing protection (accounts...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... BETWEEN FREIGHT SERVICE AND PASSENGER SERVICE FOR RAILROADS 1 Operating Expenses-Transportation § 1242.58... 49 Transportation 9 2011-10-01 2011-10-01 false Operating signals and interlockers, operating... Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD,...

  2. 18 CFR 45.9 - Automatic authorization of certain interlocking positions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... constitute a failure to satisfy this condition, and will constitute automatic denial. (c) Informational... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Automatic authorization... APPLICATION FOR AUTHORITY TO HOLD INTERLOCKING POSITIONS § 45.9 Automatic authorization of...

  3. 18 CFR 45.9 - Automatic authorization of certain interlocking positions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... constitute a failure to satisfy this condition, and will constitute automatic denial. (c) Informational... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Automatic authorization... APPLICATION FOR AUTHORITY TO HOLD INTERLOCKING POSITIONS § 45.9 Automatic authorization of...

  4. 18 CFR 45.9 - Automatic authorization of certain interlocking positions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... constitute a failure to satisfy this condition, and will constitute automatic denial. (c) Informational... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Automatic authorization... APPLICATION FOR AUTHORITY TO HOLD INTERLOCKING POSITIONS § 45.9 Automatic authorization of...

  5. 18 CFR 45.9 - Automatic authorization of certain interlocking positions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... constitute a failure to satisfy this condition, and will constitute automatic denial. (c) Informational... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Automatic authorization... APPLICATION FOR AUTHORITY TO HOLD INTERLOCKING POSITIONS § 45.9 Automatic authorization of...

  6. 46 CFR 111.70-7 - Remote control, interlock, and indicator circuits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Remote control, interlock, and indicator circuits. 111.70-7 Section 111.70-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Motor Circuits, Controllers, and Protection §...

  7. 46 CFR 111.70-7 - Remote control, interlock, and indicator circuits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Remote control, interlock, and indicator circuits. 111.70-7 Section 111.70-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Motor Circuits, Controllers, and Protection §...

  8. 46 CFR 111.70-7 - Remote control, interlock, and indicator circuits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Remote control, interlock, and indicator circuits. 111.70-7 Section 111.70-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Motor Circuits, Controllers, and Protection §...

  9. 46 CFR 111.70-7 - Remote control, interlock, and indicator circuits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Remote control, interlock, and indicator circuits. 111.70-7 Section 111.70-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Motor Circuits, Controllers, and Protection §...

  10. Enhanced Mechanical Performance of Bio-Inspired Hybrid Structures Utilising Topological Interlocking Geometry

    NASA Astrophysics Data System (ADS)

    Djumas, Lee; Molotnikov, Andrey; Simon, George P.; Estrin, Yuri

    2016-05-01

    Structural composites inspired by nacre have emerged as prime exemplars for guiding materials design of fracture-resistant, rigid hybrid materials. The intricate microstructure of nacre, which combines a hard majority phase with a small fraction of a soft phase, achieves superior mechanical properties compared to its constituents and has generated much interest. However, replicating the hierarchical microstructure of nacre is very challenging, not to mention improving it. In this article, we propose to alter the geometry of the hard building blocks by introducing the concept of topological interlocking. This design principle has previously been shown to provide an inherently brittle material with a remarkable flexural compliance. We now demonstrate that by combining the basic architecture of nacre with topological interlocking of discrete hard building blocks, hybrid materials of a new type can be produced. By adding a soft phase at the interfaces between topologically interlocked blocks in a single-build additive manufacturing process, further improvement of mechanical properties is achieved. The design of these fabricated hybrid structures has been guided by computational work elucidating the effect of various geometries. To our knowledge, this is the first reported study that combines the advantages of nacre-inspired structures with the benefits of topological interlocking.

  11. Three-component self-assembly of a series of triply interlocked Pd12 coordination prisms and their non-interlocked Pd6 analogues.

    PubMed

    Bar, Arun Kumar; Raghothama, Srinivasarao; Moon, Dohyun; Mukherjee, Partha Sarathi

    2012-03-12

    Template-assisted formation of multicomponent Pd(6) coordination prisms and formation of their self-templated triply interlocked Pd(12) analogues in the absence of an external template have been established in a single step through Pd-N/Pd-O coordination. Treatment of cis-[Pd(en)(NO(3))(2)] with K(3) tma and linear pillar 4,4'-bpy (en=ethylenediamine, H(3) tma=benzene-1,3,5-tricarboxylic acid, 4,4'-bpy=4,4'-bipyridine) gave intercalated coordination cage [{Pd(en)}(6)(bpy)(3)(tma)(2)](2)[NO(3)](12) (1) exclusively, whereas the same reaction in the presence of H(3) tma as an aromatic guest gave a H(3) tma-encapsulating non-interlocked discrete Pd(6) molecular prism [{Pd(en)}(6)(bpy)(3)(tma)(2)(H(3)tma)(2)][NO(3)](6) (2). Though the same reaction using cis-[Pd(NO(3))(2)(pn)] (pn=propane-1,2-diamine) instead of cis-[Pd(en)(NO(3))(2)] gave triply interlocked coordination cage [{Pd(pn)}(6)(bpy)(3)(tma)(2)](2)[NO(3)](12) (3) along with non-interlocked Pd(6) analogue [{Pd(pn)}(6)(bpy)(3) (tma)(2)](NO(3))(6) (3'), and the presence of H(3) tma as a guest gave H(3) tma-encapsulating molecular prism [{Pd(pn)}(6)(bpy)(3)(tma)(2)(H(3) tma)(2)][NO(3)](6) (4) exclusively. In solution, the amount of 3' decreases as the temperature is decreased, and in the solid state 3 is the sole product. Notably, an analogous reaction using the relatively short pillar pz (pz=pyrazine) instead of 4,4'-bpy gave triply interlocked coordination cage [{Pd(pn)}(6) (pz)(3)(tma)(2)](2)[NO(3)](12) (5) as the single product. Interestingly, the same reaction using slightly more bulky cis-[Pd(NO(3))(2)(tmen)] (tmen=N,N,N',N'-tetramethylethylene diamine) instead of cis-[Pd(NO(3))(2)(pn)] gave non-interlocked [{Pd(tmen)}(6)(pz)(3)(tma)(2)][NO(3)](6) (6) exclusively. Complexes 1, 3, and 5 represent the first examples of template-free triply interlocked molecular prisms obtained through multicomponent self-assembly. Formation of the complexes was supported by IR and multinuclear NMR ((1)H and (13)C) spectroscopy

  12. Expanding the scope of the anion templated synthesis of interlocked structures.

    PubMed

    Spence, Graeme T; Beer, Paul D

    2013-02-19

    Nature achieves impressively strong and selective complexation of small molecule anions through the elaborate binding sites of sophisticated proteins. Inspired by these examples, we have developed an anion templation strategy for the synthesis of mechanically interlocked host structures for anion recognition applications. Upon removal of the discrete anionic templating species, such host systems possess unique, three-dimensional, geometrically restrained cavities containing convergent hydrogen bond donor atoms. Such structures exhibit high affinity binding selectivity toward complementary anions. This Account describes recent advances in this anion templation meth odology, demonstrating the versatility and scope of this approach, and progressing to more diverse architectures. Specifically, we have prepared an expansive range of interlocked hosts with enhanced anion recognition properties, such as the ability to operate effectively in competitive aqueous media. We have produced these structures through the utilization of a new anion templated amide condensation synthetic method and through the incorporation of a range of different anion binding motifs, such as groups capable of effective solution-phase halogen bonding interactions. Importantly, direct comparisons between halogen bonding and hydrogen bonding systems reveal impressively magnified anion recognition properties for halogen bonding interlocked host systems. We have also employed the anion templation strategy successfully to construct selective electrochemical and luminescent anion sensors, as well as architectures of increasing complexity, such as a triply interlocked capsule and a handcuff catenane. The synthesis of these latter examples presents greater challenges; however, such molecules offer additional applications in higher order recognition and sensing and in switchable molecular devices. Having established anion templation as a viable synthetic route to interlocked architectures, we have used this

  13. Micromotion in the fracture healing of closed distal metaphyseal tibial fractures: A multicentre prospective study.

    PubMed

    Vicenti, G; Pesce, V; Tartaglia, N; Abate, A; Mori, C M; Moretti, B

    2014-12-01

    The dynamic locking screw (DLS) in association with minimally invasive plate osteosynthesis (MIPO) in a bridging construct for simple metadiaphyseal long bone fractures enables modulation of the rigidity of the system and facilitates the development of early and triplanar bone callus. Twenty patients affected by distal tibial fracture were treated with MIPO bridging technique and DLS at the proximal side of the fracture. Time of consolidation, quality of the reduction, complications and American Orthopaedic Foot and Ankle Society (AOFAS) score were monitored and the results compared with those from a control group treated with only standard screws on both fracture sides. Student t-test for independent samples was used for the comparison of means between the two groups. Chi-square test was used for the comparison of proportions. A multiple logistic regression model was constructed to assess the possible confounding effects. Performance was considered significant for p<0.05. The mean healing time was 17.6 ± 2.8 weeks in the group treated with standard screws and 13.5 ± 1.8 weeks in the group treated with DLS (t=5.5, p<0.0001). The DLS was associated with early healing and triplanar bone callus.

  14. Effect of Frictions on the Ballistic Performance of a 3D Warp Interlock Fabric: Numerical Analysis

    NASA Astrophysics Data System (ADS)

    Ha-Minh, Cuong; Boussu, François; Kanit, Toufik; Crépin, David; Imad, Abdellatif

    2012-06-01

    3D interlock woven fabrics are promising materials to replace the 2D structures in the field of ballistic protection. The structural complexity of this material caused many difficulties in numerical modeling. This paper presents a new tool that permits to generate a geometry model of any woven fabric, then, mesh this model in shell or solid elements, and apply the mechanical properties of yarns to them. The tool shows many advantages over existing software. It is very handy in use with an organization of the functions in menu and using a graphic interface. It can describe correctly the geometry of all textile woven fabrics. With this tool, the orientation of the local axes of finite elements following the yarn direction facilitates defining the yarn mechanical properties in a numerical model. This tool can be largely applied because it is compatible with popular finite element codes such as Abaqus, Ansys, Radioss etc. Thanks to this tool, a finite element model was carried out to describe a ballistic impact on a 3D warp interlock Kevlar KM2® fabric. This work focuses on studying the effect of friction onto the ballistic impact behavior of this textile interlock structure. Results showed that the friction among yarns affects considerably on the impact behavior of this fabric. The effect of the friction between projectile and yarn is less important. The friction plays an important role in keeping the fabric structural stability during the impact event. This phenomenon explained why the projectile is easier to penetrate this 3D warp interlock fabric in the no-friction case. This result also indicates that the ballistic performance of the interlock woven fabrics can be improved by using fibers with great friction coefficients.

  15. Finite element analysis of Stryker Xia pedicle screw in artificial bone samples with and without supplemental cement augmentation.

    PubMed

    Pfeiffer, Ferris M; Choma, Theodore J; Kueny, Rebecca

    2015-01-01

    A validated, using in vitro biomechanical testing, finite element model was used to evaluate the affects of (1) cement augmentation and (2) an intact posterior cortex in osteoporotic bone. The presence of augmentation and/or a posterior cortical cortex increased the stabilization of the pedicle screw 2-5 fold. Placement of cement influenced failure load and toggle; with distal placement having the largest increase in failure load and decrease in cephalad-caudad toggle. The presence of posterior cortex caused a decrease in the amount of toggle, a proximal shift of the center of rotation and an increase in the maximum failure force.

  16. Impact of screw elements on continuous granulation with a twin-screw extruder.

    PubMed

    Djuric, Dejan; Kleinebudde, Peter

    2008-11-01

    The influence of different screw element types on wet granulation process with a twin-screw extruder was investigated. Lactose granules were prepared with different screw configurations such as conveying, combing mixer and kneading elements. The use of kneading blocks led to an almost complete agglomeration of lactose, whereas kneading and combing mixer elements resulted in smaller granules in comparison. Granule porosity varied between 17.4% and 50.6%. Granule friability values ranged from 1.2% to 38.5%. Conveying elements led to the most porous and friable granules, whereas kneading blocks produced the densest and least friable granules. Combing mixer elements produced granules with median properties. A linear correlation between granule porosity and the natural logarithm of granule friability was detected. Flowability of granules was also influenced by the element type. Compressed granules with higher granule porosities resulted in tablets with higher tensile strength values and vice versa. Twin-screw extruders proved to be a versatile tool for wet granulation. By the choice of a suitable screw element granule and tablet characteristics were influenced.

  17. Analysis of Modeling Parameters on Threaded Screws.

    SciTech Connect

    Vigil, Miquela S.; Brake, Matthew Robert; Vangoethem, Douglas

    2015-06-01

    Assembled mechanical systems often contain a large number of bolted connections. These bolted connections (joints) are integral aspects of the load path for structural dynamics, and, consequently, are paramount for calculating a structure's stiffness and energy dissipation prop- erties. However, analysts have not found the optimal method to model appropriately these bolted joints. The complexity of the screw geometry cause issues when generating a mesh of the model. This paper will explore different approaches to model a screw-substrate connec- tion. Model parameters such as mesh continuity, node alignment, wedge angles, and thread to body element size ratios are examined. The results of this study will give analysts a better understanding of the influences of these parameters and will aide in finding the optimal method to model bolted connections.

  18. Twin screw granulation - review of current progress.

    PubMed

    Thompson, M R

    2015-01-01

    Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique.

  19. Effects of analgesia of the distal interphalangeal joint and navicular bursa on experimental lameness caused by solar pain in horses.

    PubMed

    Sardari, K; Kazemi, H; Mohri, M

    2002-11-01

    It has been hypothesized that pain originating from the dorsal margin of the sole of the hoof in horses can be attenuated by analgesia of either the distal interphalangeal (DIP) joint, or of the navicular bursa (NB). To test this hypothesis, an experimental lameness was induced in the toe region of the left forelimb in six adult horses. After this, both synovial structures were blocked and the effects on the lameness were semi-quantitatively scored. Lameness was induced by creating pressure on the dorsal margin of the sole with the help of set-screws that were screwed into a nut, welded to the inside of each branch of the shoe. Gaits were recorded on a videotape before and after application of the screws, and after application of either a local anaesthetic or saline into the DIP joint or NB. The gaits were independently evaluated by two blinded clinicians and scored. Lameness scores were high after application of the screws and remained high after the administration of saline, but decreased significantly (P < 0.05) after administration of the local anaesthetic. Analgesia of the DIP joint as well as the NB appeared to be able to desensitize a portion of the sole. It was concluded that pain arising from the toe region of the sole should not be excluded as a cause of lameness when lameness is attenuated by analgesia of the DIP joint, or of the NB.

  20. Biomechanical analysis of expansion screws and cortical screws used for ventral plate fixation on the cervical spine

    PubMed Central

    Ullrich, Bernhard; Huber, Gerd; Morlock, Michael M.

    2009-01-01

    Compared to bicortical screws, the surgical risk of injuring intraspinal structures can be minimized with the use of monocortical screws. However, this reduction should not be achieved at the expense of the stability of the fixation. With monocortical stabilization, the expansion screws have the potential of absorbing high loads. Therefore, they are expected to be a suitable alternative to bicortical screws for revision surgeries and in osteoporotic bone. The purpose of this in vitro study was to investigate the stiffness of the two screw-plate systems used for ventral stabilization of the cervical spine, by focusing on the suitability of expansion screws as tools for revision treatments. The study was conducted in ten functional units of human cervical spines. The device sample stiffness was determined for four conditions using a turning moment of 2.25 N m each around one of the three principle axes. The conditions were native, destabilized, primarily stabilized with one of the screw-plate systems, followed by secondary stabilization using the expansion screw implant. The stabilized samples achieved a comparable, in most cases higher stiffness than the native samples. The samples undergoing secondary stabilization using expansion screws tend to display greater stiffness for all three axes compared to the primarily stabilized samples. The achieved tightening moment of the screws was higher than the one achieved with primary fixation. Both plates revealed similar primary stability. Revision surgeries with secondary instrumentation achieve a high stiffness of the screwed up segments. Monocortical expansion screws combined with a trapezoidal plate allow ventral stabilization of the cervical spine that is comparable to the plate fixation using bicortical screws. PMID:19588171

  1. Nonlinear contact analysis of preload in dental implant screws.

    PubMed

    Sakaguchi, R L; Borgersen, S E

    1995-01-01

    Clinical studies indicate that loosening or fracture of dental implant prostheses occurs in 5% to 45% of cases during the first year. The nature of loosening or displacement of prosthetic components is complex, since it involves cycling fatigue, oral fluids, and varied chewing patterns and loads. A finite element contact analysis method was used to study the load-transfer mechanism between prosthetic components caused by torque application to the threaded fasteners used for assembly. Screw elongation is achieved while allowing for elastic recovery of the screw to produce a clamping force on the fastened elements. Clamping forces were additive along the axis of the prosthetic components. When the gold retaining screw is fastened into the abutment screw, clamping force on the implant is increased at the expense of decreasing the clamping force at the abutment screw-abutment interface by 50%. Maximum tensile stresses in the screws after preload were less than 55% of the yield stress.

  2. Passage of an Anterior Odontoid Screw through Gastrointestinal Tract

    PubMed Central

    Leitner, L.; Brückmann, C. I.; Gilg, M. M.; Bratschitsch, G.; Radl, R.

    2017-01-01

    Purpose. Anterior screw fixation has become a popular surgical treatment method for instable odontoid fractures. Screw loosening and migration are a rare, severe complication following anterior odontoid fixation, which can lead to esophagus perforation and requires revision operation. Methods. We report a case of screw loosening and migration after anterior odontoid fixation, which perforated the esophagus and was excreted without complications in a 78-year-old male patient. Results. A ventral dislocated anterior screw perforated through the esophagus after eight years after implantation and was excreted through the gastrointestinal (GI) tract. At a 6-month follow-up after the event the patient was asymptomatic. Conclusion. Extrusion via the GI tract is not safe enough to be considered as a treatment option for loosened screws. Some improvements could be implemented to prevent such an incident. Furthermore, this case is a fine example that recent preoperative imaging is mandatory before revision surgery for screw loosening. PMID:28194180

  3. Pullout strength of fixation screws from polymethylmethacrylate bone cement.

    PubMed

    Flahiff, C M; Gober, G A; Nicholas, R W

    1995-05-01

    Polymethylmethacrylate bone cement is often used to fill voids and increase the strength of osteoporotic and pathological bone. However, it is unclear as to which method of cement augmentation provides optimal screw fixation. This study was conducted to determine which of the current cement augmentation techniques provides the strongest construct when used in association with orthopaedic fixation screws. Pullout strength was determined for screws placed in sawbones with no cement, soft cement, doughy cement and hard cement after drilling and tapping. All cement-screw constructs were significantly stronger than the no cement group. Screws placed in doughy cement had a significantly higher pullout force than those placed in hard cement. Pullout strength of screws placed in soft cement was intermediate between the other cement techniques but not significantly different from either group.

  4. The usefulness of electrical stimulation for assessing pedicle screw placements.

    PubMed

    Toleikis, J R; Skelly, J P; Carlvin, A O; Toleikis, S C; Bernard, T N; Burkus, J K; Burr, M E; Dorchak, J D; Goldman, M S; Walsh, T R

    2000-08-01

    The purpose of this study was to further establish the efficacy of pedicle screw stimulation as a monitoring technique to avoid nerve root injury during screw placement. The study population consisted of 662 patients in whom 3,409 pedicle screws were placed and tested by electrical stimulation. If stimulation resulted in a myogenic response at a stimulation intensity of 10 mA or less, the placement of the screw was inspected. Inspection was necessary for 3.9% of the screw placements in 15.4% of the study population. None of the patients in the study experienced any new postoperative neurologic deficits. These findings provide guidelines for the interpretation of stimulation data and support the use of this technique as an easy, inexpensive, and quick method to reliably assess screw placements and protecting neurological function.

  5. Research on an intelligent ball-screw measuring instrument

    NASA Astrophysics Data System (ADS)

    Fu, Pan; Chen, Yong-Le; Zeng, Quan-Kun; Xiang, Lin-Kui

    1993-09-01

    Ball screw are widely used in the steering-gear of automobile, aero-mechanism, machine tools and precision instrument. Since the thread form is referred to as a Gothic arch, so it is difficult to measure the ball screw. The traditional screw measuring method is "three wire" method or "three ball" method. The weakness of these methods is that the measuring process is too complicated or the measuring precision is not high. We have developed an intelligent ball screw measuring instrument. The instrument can measure the ball center diameter of ball screw. Using a new measuring method("two wire and one ball" method), the instrument has high measuring precision, high reliability and it is easy to operate.The 8098 microcomputer system in the instrument can control the measuring process and accomplish data collecting and processing automatically. This measuring instrument can be used on the production site for fast and precise measurement of ball screw.

  6. Screws, Propellers and Fans Based on a Mobius Strip

    NASA Technical Reports Server (NTRS)

    Seiner, John M.; Backley, Floyd D.; Gilinsky, Mikhail

    1998-01-01

    A Mobius strip concept is intended for improving the working efficiency of propellers and screws. Applications involve cooling, boat propellers, mixing in appliance, blenders, and helicopters. Several Mobius shaped screws for the average size kitchen mixers have been made and tested. The tests have shown that the mixer with the Mobius shaped screw pair is most efficient, and saves more than 30% of the electric power by comparison with the standard. The created video film about these tests illustrates efficiency of Mobius shaped screws.

  7. Retrieval of a stripped abutment screw: a clinical report.

    PubMed

    Maalhagh-Fard, Ahmad; Jacobs, Leyvee Cabanilla

    2010-10-01

    Mechanical complications, such as loosening or damaging of the prosthetic components of an osseointegrated implant, may occur. Stripping of the implant abutment screw head can be a serious problem which can render an implant unusable. This report describes a clinical situation involving a patient who presented with a fractured screw-retained interim crown. Upon further examination, it was determined that the abutment screw head was stripped. There was limited access and visibility in this situation since the implant was a bone-level implant. The procedure used for the removal of the stripped abutment screw head is described in detail in this clinical report.

  8. The Efficacy of Hydroxyapatite for Screw Augmentation in Osteoporotic Patients

    PubMed Central

    Jang, Sang Hoon; Lee, June Ho; Cho, Ji Young; Lee, Ho-Yeon; Lee, Sang-Ho

    2013-01-01

    The stability of screw constructs is of considerable importance in determining the outcome, especially in spinal osteoporosis. Polymethylmethacrylate (PMMA) has been proven as an effective material for increasing the pullout strength of pedicle screws inserted into the osteoporotic bones. However, PMMA has several disadvantages, such as its exothermic properties, the risk of neural injury in the event of extravasation, and difficulties in performing revision surgery. In the current study, we used hydroxyapatite (HA) cement for screw augmentation in spinal osteoporosis. We conclude that HA cement is a useful tool for screw augmentation and recommend it as a promising option for spinal instrumentation in osteoporotic patients. PMID:24201099

  9. Minimally Invasive Technique for PMMA Augmentation of Fenestrated Screws

    PubMed Central

    Kogias, Evangelos; Sircar, Ronen; Krüger, Marie T.; Volz, Florian; Scheiwe, Christian; Hubbe, Ulrich

    2015-01-01

    Purpose. To describe the minimally invasive technique for cement augmentation of cannulated and fenestrated screws using an injection cannula as well as to report its safety and efficacy. Methods. A total of 157 cannulated and fenestrated pedicle screws had been cement-augmented during minimally invasive posterior screw-rod spondylodesis in 35 patients from January to December 2012. Retrospective evaluation of cement extravasation and screw loosening was carried out in postoperative plain radiographs and thin-sliced triplanar computed tomography scans. Results. Twenty-seven, largely prevertebral cement extravasations were detected in 157 screws (17.2%). None of the cement extravasations was causing a clinical sequela like a new neurological deficit. One screw loosening was noted (0.6%) after a mean follow-up of 12.8 months. We observed no cementation-associated complication like pulmonary embolism or hemodynamic insufficiency. Conclusions. The presented minimally invasive cement augmentation technique using an injection cannula facilitates convenient and safe cement delivery through polyaxial cannulated and fenestrated screws during minimally invasive screw-rod spondylodesis. Nevertheless, the optimal injection technique and design of fenestrated screws have yet to be identified. This trial is registered with German Clinical Trials DRKS00006726. PMID:26075297

  10. Biomechanical study of different plate configurations for distal humerus osteosynthesis.

    PubMed

    Bogataj, M; Kosel, F; Norris, R; Krkovic, M; Brojan, M

    2015-05-01

    Fractures of the distal humerus are most commonly fixed by open reduction and internal fixation, using plates and screws, either in a locking or in a non-locking construct. Three different plating systems are commonly used in practice. The most important differences between them are in plate orientation, which affects both the rigidity of the osteosynthesis and invasiveness of the surgical procedure. Unfortunately, there is no common agreement between surgeons about which plate configuration brings the best clinical outcome. In this study, we investigate the theoretical rigidity of plate osteosyntheses considering two types of AO/ASIF configurations (90° angle between plates), Mayo clinic (Acumed) configuration (180° between plates) and dorsal fixation of both plates. We also compared the results for cases with and without contact between the bone fragments. In the case of no bone contact, the Mayo clinic plate configuration is found to be the most rigid, followed by both AO/ASIF plate configurations, and the least rigid system is the Korosec plate configuration. On the other hand, no significant differences between all types of fixation configurations are found in cases with contact in-between the bone fragments. Our findings show that this contact is very important and can compensate for the lack of load carrying capacity of the implants. This could therefore incite other implant fixation solutions, leading to less invasive surgical procedures and consequently improved clinical outcome.

  11. Percutaneous K-wire fixation versus palmar plating with locking screws for Colles' fractures.

    PubMed

    Hollevoet, Nadine; Vanhoutie, Tom; Vanhove, Wim; Verdonk, René

    2011-04-01

    Different methods exist to treat distal radius fractures. A prospective randomized study was conducted to establish whether palmar plate fixation with locking screws gave better results than percutaneous K-wire fixation in patients over 50 years of age. Only fractures with dorsal displacement after a simple fall were included in the study. Twenty wrists were treated with K-wires and 20 with a plate. Radiological parameters were measured on preoperative radiographs and at five weeks postoperatively. Clinical results and DASH scores were determined at three months postoperatively and at more than one year. No significant difference in radial inclination, palmar tilt, clinical outcome and DASH score was found between plating and K-wires, but the mean difference in ulnar variance between pre- and postoperative radiographs was significantly better with plates. It can be concluded that plates were superior to K-wires in restoring ulnar variance, but functional outcome was similar with both techniques.

  12. [Interlocking medullary nailing. Indications, technic with a new guiding instrument. Analysis of the 1st 50 operations].

    PubMed

    Berentley, G

    1976-01-01

    After a review of Küntsher's intramedullary nailing, the author resumed the informations about the interlocking medullary nail and its technique. A new device, as a guide instrument for easier application of the transverse bolts was constructed on the basis of authors concept. Using the new technique and guide instrument X-ray television controll is not necessary for placing the bolts in their right places through a small incision. The time of operation and the risk of infection was also diminished by the new technique. The indications for the interlocking medullary nailing have been completed by the author with the pathologic fractures. The first 50 cases, treated by the new technique of the interlocking medullary nailing are analysed and a few cases are reported in detail. Good results have been obtained as regards both the bone union and the functional results. Based on the good results the new technique of the interlocking medullary nailing is recommended by the author.

  13. Next Generation Fast RF Interlock Module and ATCA Adapter for ILC High Availability RF Test Station Demonstration

    SciTech Connect

    Larsen, R

    2009-10-17

    High availability interlocks and controls are required for the ILC (International Linear Collider) L-Band high power RF stations. A new F3 (Fast Fault Finder) VME module has been developed to process both fast and slow interlocks using FPGA logic to detect the interlock trip excursions. This combination eliminates the need for separate PLC (Programmable Logic Controller) control of slow interlocks. Modules are chained together to accommodate as many inputs as needed. In the next phase of development the F3's will be ported to the new industry standard ATCA (Advanced Telecom Computing Architecture) crate (shelf) via a specially designed VME adapter module with IPMI (Intelligent Platform Management Interface). The goal is to demonstrate auto-failover and hot-swap for future partially redundant systems.

  14. Finite element analysis of osteosynthesis screw fixation in the bone stock: an appropriate method for automatic screw modelling.

    PubMed

    Wieding, Jan; Souffrant, Robert; Fritsche, Andreas; Mittelmeier, Wolfram; Bader, Rainer

    2012-01-01

    The use of finite element analysis (FEA) has grown to a more and more important method in the field of biomedical engineering and biomechanics. Although increased computational performance allows new ways to generate more complex biomechanical models, in the area of orthopaedic surgery, solid modelling of screws and drill holes represent a limitation of their use for individual cases and an increase of computational costs. To cope with these requirements, different methods for numerical screw modelling have therefore been investigated to improve its application diversity. Exemplarily, fixation was performed for stabilization of a large segmental femoral bone defect by an osteosynthesis plate. Three different numerical modelling techniques for implant fixation were used in this study, i.e. without screw modelling, screws as solid elements as well as screws as structural elements. The latter one offers the possibility to implement automatically generated screws with variable geometry on arbitrary FE models. Structural screws were parametrically generated by a Python script for the automatic generation in the FE-software Abaqus/CAE on both a tetrahedral and a hexahedral meshed femur. Accuracy of the FE models was confirmed by experimental testing using a composite femur with a segmental defect and an identical osteosynthesis plate for primary stabilisation with titanium screws. Both deflection of the femoral head and the gap alteration were measured with an optical measuring system with an accuracy of approximately 3 µm. For both screw modelling techniques a sufficient correlation of approximately 95% between numerical and experimental analysis was found. Furthermore, using structural elements for screw modelling the computational time could be reduced by 85% using hexahedral elements instead of tetrahedral elements for femur meshing. The automatically generated screw modelling offers a realistic simulation of the osteosynthesis fixation with screws in the adjacent

  15. Percutaneous Cannulated Compression Screw Osteosynthesis in Phalanx Fractures: The Surgical Technique, the Indications, and the Results

    PubMed Central

    Kisch, Tobias; Wenzel, Eike; Mailänder, Peter; Stang, Felix

    2017-01-01

    Objective: Fractures of metacarpals and phalanges are very common fractures, and there are a lot of treatment modalities. The purpose of the study was to describe the technique of percutaneous fixation of phalangeal fractures using a cannulated compression screw fixation system and its results. Methods: We conducted a prospective clinical study on 43 patients with different types of phalangeal fractures undergoing a percutaneous cannulated compression screw osteosynthesis. Parameters such as average operation time and clinical outcome were evaluated postoperatively. Results: Forty-three patients were treated using a percutaneous cannulated compression screw fixation system for phalanx fractures of the proximal (n = 26), middle phalanx (n = 16), or distal phalanx (n = 1). All fractures healed after 6 to 8 weeks except in 1 patient with secondary loss of reduction occurring 2.5 weeks after surgery. No infections were observed. The mean total active motion values were 247.56° ±16.16° and 244.35° ± 11.61° for the intra-articular fracture and 251.25° ± 19.86° for the shaft fractures; the mean Disabilities of the Arm, Shoulder, and Hand (DASH) score 3 months after the surgery was 1.67 ± 2.74. Conclusions: The advantages of this technique are the avoidance of an open procedure requiring extensive soft-tissue dissection with the risks of tendon adhesions and the achievement of interfragmentary compression. Because of the interfragmentary compression, it is superior to simple K-wires. With regard to indications, our primary focus was on unicondylar proximal interphalangeal joint fractures, shaft fractures, and simple oblique 2-fragment fractures. PMID:28293333

  16. Distal realignment (tibial tuberosity transfer).

    PubMed

    Feller, Julian Ashley

    2012-09-01

    Although tibial tuberosity (TT) transfer has for many years been the basis of many protocols for the management of patellar instability, the role of pure medial transfer in particular appears to be declining. In contrast, the greater recognition of the importance of patella alta as a predisposing factor to recurrent patellar dislocation has resulted in a resurgence in the popularity of distal TT transfer. When TT transfer is performed, the direction and amount of transfer is based on the patellar height and the lateralization of the TT relative to the trochlear groove. Patellar height is best assessed on a lateral radiograph with the knee in flexion using a ratio that uses the articular surface of the patella in relation to the height above the tibia. Assessment of lateralization of the TT relative to the trochlear groove can be made using either computed tomography or magnetic resonance imaging scans.

  17. The Effects of Interlocking a Universal Hip Cementless Stem on Implant Subsidence and Mechanical Properties of Cadaveric Canine Femora

    PubMed Central

    Buks, Yonathan; Stover, Susan M.; Garcia‐Nolen, Tanya C.

    2016-01-01

    Objective To determine if an interlocking bolt would limit subsidence of the biological fixation universal hip (BFX®) femoral stem under cyclic loading and enhance construct stiffness, yield, and failure properties. Study Design Ex vivo biomechanical study. Animals Cadaveric canine femora (10 pairs). Methods Paired femora implanted with a traditional stem or an interlocking stem (constructs) were cyclically loaded at walk, trot, and gallop loads while implant and bone motions were captured using kinematic markers and high‐speed video. Constructs were then loaded to failure to evaluate failure mechanical properties. Results Implant subsidence was greater (P = .037) for the traditional implant (4.19 mm) than the interlocking implant (0.78 mm) only after gallop cyclic loading, and cumulatively after walk, trot, and gallop cyclic loads (5.20 mm vs. 1.28 mm, P = .038). Yield and failure loads were greater (P = .029 and .002, respectively) for the interlocking stem construct (1155 N and 2337 N) than the traditional stem construct (816 N and 1405 N). Version angle change after cyclic loading was greater (P = .020) for the traditional implant (3.89 degrees) than for the interlocking implant (0.16 degrees), whereas stem varus displacement at failure was greater (P = .008) for the interlocking implant (1.5 degrees) than the traditional implant (0.17 degrees). Conclusion Addition of a stabilizing bolt enhanced construct stability and limited subsidence of a BFX® femoral stem. Use of the interlocking implant may decrease postoperative subsidence. However, in vivo effects of the interlocking bolt on osseointegration, bone remodeling, and stress shielding are unknown. PMID:26767439

  18. NSTX Protection And Interlock Systems For Coil And Powers Supply Systems

    SciTech Connect

    X. Zhao, S. Ramakrishnan, J. Lawson, C.Neumeyer, R. Marsala, H. Schneider, Engineering Operations

    2009-09-24

    NSTX at Princeton Plasma Physics Laboratory (PPPL) requires sophisticated plasma positioning control system for stable plasma operation. TF magnetic coils and PF magnetic coils provide electromagnetic fields to position and shape the plasma vertically and horizontally respectively. NSTX utilizes twenty six coil power supplies to establish and initiate electromagnetic fields through the coil system for plasma control. A power protection and interlock system is utilized to detect power system faults and protect the TF coils and PF coils against excessive electromechanical forces, overheating, and over current. Upon detecting any fault condition the power system is restricted, and it is either prevented from initializing or suppressed to de-energize coil power during pulsing. Power fault status is immediately reported to the computer system. This paper describes the design and operation of NSTX's protection and interlocking system and possible future expansion.

  19. Interlocking directorates in Irish companies using a latent space model for bipartite networks.

    PubMed

    Friel, Nial; Rastelli, Riccardo; Wyse, Jason; Raftery, Adrian E

    2016-06-14

    We analyze the temporal bipartite network of the leading Irish companies and their directors from 2003 to 2013, encompassing the end of the Celtic Tiger boom and the ensuing financial crisis in 2008. We focus on the evolution of company interlocks, whereby a company director simultaneously sits on two or more boards. We develop a statistical model for this dataset by embedding the positions of companies and directors in a latent space. The temporal evolution of the network is modeled through three levels of Markovian dependence: one on the model parameters, one on the companies' latent positions, and one on the edges themselves. The model is estimated using Bayesian inference. Our analysis reveals that the level of interlocking, as measured by a contraction of the latent space, increased before and during the crisis, reaching a peak in 2009, and has generally stabilized since then.

  20. D0 Central Tracking Solenoid Energization, Controls, Interlocks and Quench Protection Operating Procedures

    SciTech Connect

    Hance, R.; /Fermilab

    1998-08-26

    This procedure is used when it is necessary to operate the solenoid energization, controls, interlocks and quench detection system. Note that a separate procedure exists for operating the solenoid 'cryogenic' systems. Only D0 Control Room Operators or the Project Electrical Engineer are qualified to execute these procedures or operate the solenoid system. This procedure assumes that the operator is familiar with using the Distributed Manufacturing Automation and Control Software (DMACS).

  1. Extended torsional tests of an interlocked bi-stem satellite boom

    NASA Technical Reports Server (NTRS)

    Abercrombie, R. A.

    1973-01-01

    The effect is reported of continued oscillations of a 1.27-cm interlocked bi-stem satellite boom. The test setup oscillated a boom continuously between set torque limits and periodically recorded its hysteresis characteristics. Results showed that repeated oscillations affected torsional characteristics and that torsional rigidity changed as a function of the number of cycles oscillated within certain torque limits. Torsional characteristics changes caused by repeated oscillations were retained.

  2. A Note on the Effectiveness of the House-Arrest Alternative for Motivating DWI Offenders to Install Ignition Interlocks

    PubMed Central

    Roth, Richard; Marques, Paul R.; Voas, Robert B.

    2009-01-01

    Problem The effectiveness of ignition interlocks at reducing drunk driving has been limited by the ability of driving-while-intoxicated (DWI) offenders to avoid court orders to install the devices. Methods In a pilot program in New Mexico, four Santa Fe County judges imposed home confinement (via electronic monitoring bracelets) on offenders who claimed to have no car or no intention to drive. Interlock installation rates for Santa Fe County were compared with all other counties in New Mexico over a 2-year program and 2-year post-program period. Results During the two program years, 70% of the drivers convicted of DWI in Santa Fe County installed interlocks, compared to only 17% in the other counties, but when the program was terminated, the Santa Fe installation rate fell by 18.8 percentage points. Summary Mandating the alternative sanction of house arrest led to the highest reported interlock installation rate for DWI offenders. Impact on Industry Impaired driving is a substantial expense to employers, particularly when it bars driving that interferes with employment. Interlocks provide a method of protecting the public while permitting the offender to drive sober. This study was directed at increasing interlock use by DWI offenders. PMID:19945556

  3. Magnesium Alloys as a Biomaterial for Degradable Craniofacial Screws

    PubMed Central

    Henderson, Sarah E.; Verdelis, Konstantinos; Maiti, Spandan; Pal, Siladitya; Chung, William L.; Chou, Da-Tren; Kumta, Prashant N.; Almarza, Alejandro J.

    2014-01-01

    Recently, magnesium (Mg) alloys have received significant attention as a potential biomaterial for degradable implants, and this study was directed at evaluating the suitability of Mg for craniofacial bone screws. The objective was to implant screws fabricated from commercially available Mg-alloys (pure Mg and AZ31) in-vivo in a rabbit mandible. First, Mg-alloy screws were compared to stainless steel screws in an in-vitro pull-out test and determined to have a similar holding strength (~40N). A finite element model of the screw was created using the pull-out test data, and the model can be used for future Mg-alloy screw design. Then, Mg-alloy screws were implanted for 4, 8, and 12 weeks, with two controls of an osteotomy site (hole) with no implant and a stainless steel screw implanted for 12 weeks. MicroCT (computed tomography) was used to assess bone remodeling and Mg-alloy degradation, both visually and qualitatively through volume fraction measurements for all time points. Histologic analysis was also completed for the Mg-alloys at 12 weeks. The results showed that craniofacial bone remodeling occurred around both Mg-alloy screw types. Pure Mg had a different degradation profile than AZ31, however bone growth occurred around both screw types. The degradation rate of both Mg-alloy screw types in the bone marrow space and the muscle were faster than in the cortical bone space at 12 weeks. Furthermore, it was shown that by alloying Mg, the degradation profile could be changed. These results indicate the promise of using Mg-alloys for craniofacial applications. PMID:24384125

  4. Modeling the Injury Prevention Impact of Mandatory Alcohol Ignition Interlock Installation in All New US Vehicles

    PubMed Central

    Flannagan, Carol A. C.; Bingham, C. Raymond; Cunningham, Rebecca M.; Rupp, Jonathan D.

    2015-01-01

    Objectives. We estimated the injury prevention impact and cost savings associated with alcohol interlock installation in all new US vehicles. Methods. We identified fatal and nonfatal injuries associated with drinking driver vehicle crashes from the Fatality Analysis Reporting System and National Automotive Sampling System’s General Estimates System data sets (2006–2010). We derived the estimated impact of universal interlock installation using an estimate of the proportion of alcohol-related crashes that were preventable in vehicles < 1 year-old. We repeated this analysis for each subsequent year, assuming a 15-year implementation. We applied existing crash-induced injury cost metrics to approximate economic savings, and we used a sensitivity analysis to examine results with varying device effectiveness. Results. Over 15 years, 85% of crash fatalities (> 59 000) and 84% to 88% of nonfatal injuries (> 1.25 million) attributed to drinking drivers would be prevented, saving an estimated $342 billion in injury-related costs, with the greatest injury and cost benefit realized among recently legal drinking drivers. Cost savings outweighed installation costs after 3 years, with the policy remaining cost effective provided device effectiveness remained above approximately 25%. Conclusions. Alcohol interlock installation in all new vehicles is likely a cost-effective primary prevention policy that will substantially reduce alcohol-involved crash fatalities and injuries, especially among young vulnerable drivers. PMID:25790385

  5. Recent Advances in the Synthesis and Functions of Reconfigurable Interlocked DNA Nanostructures.

    PubMed

    Lu, Chun-Hua; Cecconello, Alessandro; Willner, Itamar

    2016-04-27

    Interlocked circular DNA nanostructures, e.g., catenanes or rotaxanes, provide functional materials within the area of DNA nanotechnology. Specifically, the triggered reversible reconfiguration of the catenane or rotaxane structures provides a means to yield new DNA switches and to use them as dynamic scaffolds for controlling chemical functions and positioning functional cargoes. The synthesis of two-ring catenanes and their switchable reconfiguration by pH, metal ions, or fuel/anti-fuel stimuli are presented, and the functions of these systems, as pendulum or rotor devices or as switchable catalysts, are described. Also, the synthesis of three-, five-, and seven-ring catenanes is presented, and their switchable reconfiguration using fuel/anti-fuel strands is addressed. Implementation of the dynamically reconfigured catenane structures for the programmed organization of Au nanoparticle (NP) assemblies, which allows the plasmonic control of the fluorescence properties of Au NP/fluorophore loads associated with the scaffold, and for the operation of logic gates is discussed. Interlocked DNA rotaxanes and their different synthetic approaches are presented, and their switchable reconfiguration by means of fuel/anti-fuel strands or photonic stimuli is described. Specifically, the use of the rotaxane as a scaffold to organize Au NP assemblies, and the control of the fluorescence properties with Au NP/fluorophore hybrids loaded on the rotaxane scaffold, are introduced. The future prospectives and challenges in the field of interlocked DNA nanostructures and the possible applications are discussed.

  6. Extending DIII-D Neutral Beam Modulated Operations with a Camac Based Total on Time Interlock

    SciTech Connect

    Baggest, D.S.; Broesch, J.D.; Phillips, J.C.

    1999-11-01

    A new total-on-time interlock has increased the operational time limits of the Neutral Beam systems at DIII-D. The interlock, called the Neutral Beam On-Time-Limiter (NBOTL), is a custom built CAMAC module utilizing a Xilinx 9572 Complex Programmable Logic Device (CPLD) as its primary circuit. The Neutral Beam Injection Systems are the primary source of auxiliary heating for DIII-D plasma discharges and contain eight sources capable of delivering 20MW of power. The delivered power is typically limited to 3.5 s per source to protect beam-line components, while a DIII-D plasma discharge usually exceeds 5 s. Implemented as a hardware interlock within the neutral beam power supplies, the NBOTL limits the beam injection time. With a continuing emphasis on modulated beam injections, the NBOTL guards against command faults and allows the beam injection to be safely spread over a longer plasma discharge time. The NBOTL design is an example of incorporating modern circuit design techniques (CPLD) within an established format (CAMAC). The CPLD is the heart of the NBOTL and contains 90% of the circuitry, including a loadable, 1 MHz, 28 bit, BCD count down timer, buffers, and CAMAC communication circuitry. This paper discusses the circuit design and implementation. Of particular interest is the melding of flexible modern programmable logic devices with the CAMAC format.

  7. Bio-inspired design of geometrically interlocked 3D printed joints

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Oliva, Noel; Kumar's Lab Team

    The morphology of the adhesive-adherend interface significantly affects the mechanical behavior of adhesive joints. As seen in some biocomposites like human skull, or the nacre of some bivalve molluscs' shells, a geometrically interlocking architecture of interfaces creates toughening and strengthening mechanisms enhancing the mechanical properties of the joint. In an attempt to characterize this mechanical interlocking mechanism, this study is focused on computational and experimental investigation of a single-lap joint with a very simple geometrically interlocked interface design in which both adherends have a square waveform configuration of the joining surfaces. This square waveform configuration contains a positive and a negative rectangular teeth per cycle in such a way that the joint is symmetric about the mid-bondlength. Both physical tests performed on 3D printed prototypes of joints and computational results indicate that the joints with square waveform design have higher strength and damage tolerance than those of joints with flat interface. In order to identify an optimal design configuration of this interface, a systematic parametric study is conducted by varying the geometric and material properties of the non-flat interface. This work was supported by Lockheed Martin (Award No: 12NZZ1).

  8. Modelling the evolution of a bi-partite network Peer referral in interlocking directorates*

    PubMed Central

    Edling, Christofer

    2010-01-01

    A central part of relational ties between social actors are constituted by shared affiliations and events. The action of joint participation reinforces personal ties between social actors as well as mutually shared values and norms that in turn perpetuate the patterns of social action that define groups. Therefore the study of bipartite networks is central to social science. Furthermore, the dynamics of these processes suggests that bipartite networks should not be considered static structures but rather be studied over time. In order to model the evolution of bipartite networks empirically we introduce a class of models and a Bayesian inference scheme that extends previous stochastic actor-oriented models for unimodal graphs. Contemporary research on interlocking directorates provides an area of research in which it seems reasonable to apply the model. Specifically, we address the question of how tie formation, i.e. director recruitment, contributes to the structural properties of the interlocking directorate network. For boards of directors on the Stockholm stock exchange we propose that a prolific mechanism in tie formation is that of peer referral. The results indicate that such a mechanism is present, generating multiple interlocks between boards. PMID:24944435

  9. Reviewed approach to defining the Active Interlock Envelope for Front End ray tracing

    SciTech Connect

    Seletskiy, S.; Shaftan, T.

    2015-09-24

    To protect the NSLS-II Storage Ring (SR) components from damage from synchrotron radiation produced by insertion devices (IDs) the Active Interlock (AI) keeps electron beam within some safe envelope (a.k.a Active Interlock Envelope or AIE) in the transverse phase space. The beamline Front Ends (FEs) are designed under assumption that above certain beam current (typically 2 mA) the ID synchrotron radiation (IDSR) fan is produced by the interlocked e-beam. These assumptions also define how the ray tracing for FE is done. To simplify the FE ray tracing for typical uncanted ID it was decided to provide the Mechanical Engineering group with a single set of numbers (x,x’,y,y’) for the AIE at the center of the long (or short) ID straight section. Such unified approach to the design of the beamline Front Ends will accelerate the design process and save valuable human resources. In this paper we describe our new approach to defining the AI envelope and provide the resulting numbers required for design of the typical Front End.

  10. Locking plate fixation of distal femoral fractures is a challenging technique: a retrospective review

    PubMed Central

    Toro, Giuseppe; Calabrò, Giampiero; Toro, Antonio; de Sire, Alessandro; Iolascon, Giovanni

    2015-01-01

    Summary Distal femoral fractures have typically a bimodal occurrence: in young people due to a high-energy trauma and in older people related to a low-energy trauma. These fractures are associated to a very high morbidity and mortality in elderly. Distal femoral fractures might be treated with plates, intramedullary nails, external fixations, and prosthesis. However, difficulties in fracture healing and the rate of complications are important clinical issues. The purpose of this retrospective review was to present our experience in treatment of distal femoral fracture in a sample of older people in order to evaluate the technical pitfalls and strategies used to face up the fractures unsuccessfully treated with locking plates. We included people aged more than 65 years, with a diagnosis of distal femoral fracture, treated with locking plates. We considered ‘unsuccessfully treated’ the cases with healing problems or hardware failures. Of the 12 patients (9 females and 3 males; mean aged 68.75 ± 3.31 years) included, we observed 3 ‘unsuccessfully cases’, 2 due to nonunions and 1 due to an early hardware failure, all treated using a condylar blade plate with a bone graft. One patient obtained a complete fracture healing after 1 year and in the other cases there was a nonunion. We observed as most common technical pitfalls: inadequate plate lengthening, fracture bridging, and number of locking screws. The use of locking plates is an emerging technique to treat these fractures but it seems more challenging than expected. In literature there is a lack of evidences about the surgical management of distal femoral fractures that is still an important challenge for the orthopaedic surgeon that has to be able to use all the fixation devices available. PMID:27134634

  11. Transforaminal lumbar interbody fusion using unilateral pedicle screws and a translaminar screw

    PubMed Central

    Lee, Sandra; Vaidya, Rahul

    2008-01-01

    Lumbar spinal fusion is advancing with minimally invasive techniques, bone graft alternatives, and new implants. This has resulted in significant reductions of operative time, duration of hospitalization, and higher success in fusion rates. However, costs have increased as many new technologies are expensive. This study was carried out to investigate the clinical outcomes and fusion rates of a low implant load construct of unilateral pedicle screws and a translaminar screw in transforaminal lumbar interbody fusion (TLIF) which reduced the cost of the posterior implants by almost 50%. Nineteen consecutive patients who underwent single level TLIF with this construct were included in the study. Sixteen patients had a TLIF allograft interbody spacer placed, while in three a polyetheretherketone (PEEK) cage was used. Follow-up ranged from 15 to 54 months with a mean of 32 months. A clinical and radiographic evaluation was carried out preoperatively and at multiple time points following surgery. An overall improvement in Oswestry scores and visual analogue scales for leg and back pain (VAS) was observed. Three patients underwent revision surgery due to recurrence of back pain. All patients showed radiographic evidence of fusion from 9 to 26 months (mean 19) following surgery. This study suggests that unilateral pedicle screws and a contralateral translaminar screw are a cheaper and viable option for single level lumbar fusion. PMID:19015896

  12. Wet granulation in a twin-screw extruder: implications of screw design.

    PubMed

    Thompson, M R; Sun, J

    2010-04-01

    Wet granulation in twin-screw extrusion machinery is an attractive technology for the continuous processing of pharmaceuticals. The performance of this machinery is integrally tied to its screw design yet little fundamental knowledge exists in this emerging field for granulation to intelligently create, troubleshoot, and scale-up such processes. This study endeavored to systematically examine the influence of different commercially available screw elements on the flow behavior and granulation mechanics of lactose monohydrate saturated at low concentration (5-12%, w/w) with an aqueous polyvinyl-pyrrolidone binder. The results of the work showed that current screw elements could be successfully incorporated into designs for wet granulation, to tailor the particle size as well as particle shape of an agglomerate product. Conveying elements for cohesive granular flows were shown to perform similar to their use in polymer processing, as effective transport units with low specific mechanical energy input. The conveying zones provided little significant change to the particle size or shape, though the degree of channel fill in these sections had a significant influence on the more energy-intensive mixing elements studied. The standard mixing elements for this machine, kneading blocks and comb mixers, were found to be effective for generating coarser particles, though their mechanisms of granulation differed significantly.

  13. Injection of coal by screw feed

    NASA Technical Reports Server (NTRS)

    Fisher, R.

    1977-01-01

    The use of the screw feeder for injecting solids through a 20 to 30 psi barrier is common practice in the cement making industry. An analytical extrapolation of that design, accounting for pressure holding characteristics of a column of solids, shows that coal can be fed to zones at several hundred psi with minimal or no loss of gas. A series of curves showing the calculated pressure gradient through a moving column of solids is presented. Mean particle size, solids velocity, and column length are parameters. Further study of this system to evaluate practicality is recommended.

  14. Roller screw electric motor ventricular assist device.

    PubMed

    Richenbacher, W E; Pae, W E; Magovern, J A; Rosenberg, G; Snyder, A J; Pierce, W S

    1986-01-01

    The roller screw electric VAD is easier to manufacture and 25% lighter than the previously described drum cam model. This device requires 12 to 15 W to pump 6 to 8 l/min with minimal hemolysis. The motor drive has functioned for periods up to 93 days in vivo with no measurable wear. The compliance chamber volume varies by 100 cc during VAD function but does so while maintaining pressure variations below 15 mmHg. Compliance chamber volume loss of 2 to 5 cc/day is explained by gas transport through SPU. The subcutaneous sampling port provides ready access to the sealed system.

  15. Translaminar screws of the axis--an alternative technique for rigid screw fixation in upper cervical spine instability.

    PubMed

    Meyer, D; Meyer, F; Kretschmer, Th; Börm, W

    2012-04-01

    C2 pedicle screws or transarticular atlantoaxial screws are technically demanding and carry an increased risk of vertebral artery injury. In up to 20% of cases, pedicle and transarticular screw placement is not possible due to a high-riding vertebral artery or very small C2 pedicles in addition to other anatomical variations. Translaminar screws have been reported to rigidly capture posterior elements of C2 and therefore appear to be a suitable alternative. We present our first experiences and clinical results with this new method in two neurosurgical spine centers. Twenty-seven adult patients were treated between 2007 and 2010 in two neurosurgical spine departments with C2 translaminar screw fixation for upper cervical spine instability of various origins (e.g., trauma, tumor, dens pseudarthrosis). Eight patients were men and 19 were women. Mean age was 68.9 years. In most cases, translaminar screws were used because of contraindications for pedicle or transarticular screws as a salvage technique. All patients were clinically assessed and had CT scans postoperatively to verify correct screw placement. Follow-up was performed with reexamination on an ambulatory basis. Mean follow-up was 7.6 months for all patients. In 27 patients, 52 translaminar screws were placed. There were no intraoperative complications. Postoperatively, we identified four screw malpositions using a new accuracy grading scale. One screw had to be revised because of violation of the spinal canal >4 mm. None of the patients had additional neurological deficits postoperatively, and all showed stable cervical conditions at follow-up. Two patients died due to causes not associated with the stabilization technique. The fusion rate for patients with C1/C2 fixation is 92.9%. Translaminar screws can be used at least as an additional technique for cases of upper cervical spine instability when pedicle screw placement is contraindicated or not possible. The current data suggest comparable

  16. Two levels above and one level below pedicle screw fixation for the treatment of unstable thoracolumbar fracture with partial or intact neurology

    PubMed Central

    Modi, Hitesh N; Chung, Kook Jin; Seo, Il Woo; Yoon, Hoi Soo; Hwang, Ji Hyo; Kim, Hong Kyun; Noh, Kyu Cheol; Yoo, Jung Han

    2009-01-01

    Background Treatment of unstable thoracolumbar fractures is controversial regarding short or long segment pedicle screw fixation. Although long level fixation is better, it can decrease one motion segment distally, thus increasing load to lower discs. Methods We retrospectively analyzed 31 unstable thoracolumbar fractures with partial or intact neurology. All patients were operated with posterior approach using pedicle screws fixed two levels above and one level below the fracture vertebra. No laminectomy, discectomy or decompression procedure was done. Posterior fusion was achieved in all. Post operative and at final follow-up radiological evaluation was done by measuring the correction and maintenance of kyphotic angle at thoracolumbar junction. Complications were also reported including implant failure. Results Average follow-up was 34 months. All patients had full recovery at final follow-up. Average kyphosis was improved from 26.7° to 4.1° postoperatively and to 6.3° at final follow-up. And mean pain scale was improved from 7.5 to 3.9 postoperatively and to 1.6 at final follow-up, All patients resumed their activity within six months. Only 4 (12%) complications were noted including only one hardware failure. Conclusion Two levels above and one level below pedicle screw fixation in unstable thoracolumbar burst fracture is useful to prevent progressive kyphosis and preserves one motion segment distally. PMID:19635134

  17. [Loosening of a Calcaneo-Stop Screw after Trampolining].

    PubMed

    Trieb, K; Fingernagel, T; Petershofer, A; Hofstaetter, S G

    2015-06-01

    Flexible flatfoot is a common malalignment in the paediatric population. Arthroereisis with a calcaneo-stop screw is an effective surgical procedure for treating juvenile flexible flatfoot after conservative measures have been fully exploited. In the present report, we describe the case of a loosening of a calcaneo-stop screw in a 12-year-old youth after excessive trampolining.

  18. Periodic Stresses in Gyroscopic Bodies, with Applications to Air Screws

    NASA Technical Reports Server (NTRS)

    Zahm, A F

    1918-01-01

    Report discusses periodic stresses in gyroscopic bodies with applications to air screws caused by particle mass. Report concludes that all modern air screws obey the laws found for plane groups of particles. In particular the two-bladers exert on the shaft a rhythmic gyroscopic torque; the multibladers a steady one; both easily calculable for any given conditions of motion and mass distribution.

  19. Long oblique distal osteotomy of the fifth metatarsal for correction of tailor's bunion: a retrospective review.

    PubMed

    London, Barry P; Stern, Stephen F; Quist, Mark A; Lee, Robert K; Picklesimer, Edison K

    2003-01-01

    A long-term retrospective review of a long oblique distal osteotomy of the fifth metatarsal for correction of a tailor's bunion deformity is presented. The technique, results, and follow-up of this procedure are described. The long oblique distal osteotomy was performed on 25 feet on 16 patients. Follow-up ranged from 11 to 110 months with an average of 64.4 months. The average preoperative intermetatarsal 4-5 angle and lateral deviation angle improved from 10.88 degrees and 4.24 degrees, respectively, to 5.52 degrees and -4.24 degrees postoperatively, respectively. A modified scoring scale for lesser metatarsal procedures was used, showing an average postoperative score of 94 out of 100 possible points. Subjectively, 96% (24 of 25) of feet that underwent surgery were rated as excellent or good. Complications included one patient with paresthesias, one soft-tissue infection, and 2 patients had irritation from screws. The authors conclude that the long oblique distal osteotomy is a viable alternative in the correction of tailor's bunion deformity.

  20. Biomechanical Performance of Variable and Fixed Angle Locked Volar Plates for the Dorsally Comminuted Distal Radius

    PubMed Central

    Martineau, D; Shorez, J; Beran, C; Dass, A G; Atkinson, P

    2014-01-01

    Background The ideal treatment strategy for the dorsally comminuted distal radius fracture continues to evolve. Newer plate designs allow for variable axis screw placement while maintaining the advantages of locked technology. The purpose of this study is to compare the biomechanical properties of one variable axis plate with two traditional locked constructs. Methods Simulated fractures were created via a distal 1 cm dorsal wedge osteotomy in radius bone analogs. The analogs were of low stiffness and rigidity to create a worst-case strength condition for the subject radius plates. This fracture-gap model was fixated using one of three different locked volar distal radius plates: a variable axis plate (Stryker VariAx) or fixed axis (DePuy DVR, Smith & Nephew Peri-Loc) designs. The constructs were then tested at physiologic loading levels in axial compression and bending (dorsal and volar) modes. Construct stiffness was assessed by fracture gap motion during the different loading conditions. As a within-study control, intact bone analogs were similarly tested. Results All plated constructs were significantly less stiff than the intact control bone models in all loading modes (p<0.040). Amongst the plated constructs, the VariAx was stiffest axially (p=0.032) and the Peri-Loc was stiffest in bending (p<0.024). Conclusion In this analog bone fracture gap model, the variable axis locking technology was stiffer in axial compression than other plates, though less stiff in bending. PMID:25328471

  1. Image-guided distal radius osteotomy using patient-specific instrument guides.

    PubMed

    Kunz, Manuela; Ma, Burton; Rudan, John F; Ellis, Randy E; Pichora, David R

    2013-08-01

    In this article, we describe a method for computer-assisted distal radius osteotomies in which computer-generated, patient-specific plastic guides are used for intraoperative guidance. Before surgery, the correction and plate location are planned using computed tomography scans for both radii and ulnae, and the planned locations of the distal and proximal drill holes for the plate are saved. A plastic, patient-specific instrument guide is created using a rapid prototyping machine into which a mirror image of intraoperative, accessible bone structure of the distal radius is integrated. This allows for unique positioning of the guide during surgery. For each planned drill location, a guidance hole is incorporated into the guide. During surgery, a conventional incision is made, and the guide is positioned on the radius. The surgeon drills the holes for the plate screws into the intact radius and performs the osteotomy using the conventional technique. Using the predrilled holes, the surgeon affixes the plate to the radius fragments. The guides are easy to integrate into the surgical workflow and minimize the need for intraoperative fluoroscopy for guidance of the procedure.

  2. The effect of percutaneous pin fixation in the treatment of distal femoral physeal fractures.

    PubMed

    Garrett, B R; Hoffman, E B; Carrara, H

    2011-05-01

    Distal femoral physeal fractures in children have a high incidence of physeal arrest, occurring in a mean of 40% of cases. The underlying nature of the distal femoral physis may be the primary cause, but other factors have been postulated to contribute to the formation of a physeal bar. The purpose of this study was to assess the significance of contributing factors to physeal bar formation, in particular the use of percutaneous pins across the physis. We reviewed 55 patients with a median age of ten years (3 to 13), who had sustained displaced distal femoral physeal fractures. Most (40 of 55) were treated with percutaneous pinning after reduction, four were treated with screws and 11 with plaster. A total of 40 patients were assessed clinically and radiologically after skeletal maturity or at the time of formation of a bar. The remaining 15 were followed up for a minimum of two years. Formation of a physeal bar occurred in 12 (21.8%) patients, with the rate rising to 30.6% in patients with high-energy injuries compared with 5.3% in those with low-energy injuries. There was a significant trend for physeal arrest according to increasing severity using the Salter-Harris classification. Percutaneous smooth pins across the physis were not statistically associated with growth arrest.

  3. A simple model of throughput calculation for single screw

    NASA Astrophysics Data System (ADS)

    Béreaux, Yves; Charmeau, Jean-Yves; Moguedet, Maël

    2007-04-01

    To be able to predict the throughput of a single-screw extruder or the metering time of an injection moulding machine for a given screw geometry, set of processing conditions and polymeric material is important both for practical and designing purposes. Our simple model show that the screw geometry is the most important parameter, followed by polymer rheology and processing conditions. Melting properties and length seem to intervene to a lesser extent. The calculations hinges on the idea of viewing the entire screw as a pump, conveying a solid and a molten fraction. The evolution of the solid fraction is the essence of the plastication process, but under particular circumstances, its influence on the throughput is nil. This allows us to get a very good estimate on the throughput and pressure development along the screw. Our calculations are compared to different sets of experiments available from the literature. We have consistent agreement both in throughput and pressure with published data.

  4. A four lumen screwing device for multiparametric brain monitoring.

    PubMed

    Feuerstein, T H; Langemann, H; Gratzl, O; Mendelowitsch, A

    2000-01-01

    We describe multiparametric monitoring in severe head trauma using a new screwing device. Our aim was to create a screw which would make the implantation of the probes and thus multiparametric monitoring easier. The new screw allows us to implant 3 probes (microdialysis, Paratrend and an intracranial pressure device) through one burr hole. The screw has four channels, the fourth being for ventricular drainage. We monitored 13 patients with severe head trauma (GCS = 3-8) for up to 7 days. Brain tissue pO2, pCO2, pH, and temperature were measured on-line with the Paratrend 7 machine. The microdialytic parameters glucose, lactate, pyruvate and glutamate were determined semi on-line with a CMA 600 enzymatic analyser. There were no complications in any of the patients that could be ascribed to the screw.

  5. Ball Screw Actuator Including an Axial Soft Stop

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Forrest, Steven Talbert (Inventor); Abel, Steve (Inventor); Woessner, George (Inventor); Hanlon, Casey (Inventor)

    2016-01-01

    An actuator includes an actuator housing, a ball screw, and an axial soft stop assembly. The ball screw extends through the actuator housing and has a first end and a second end. The ball screw is coupled to receive a drive force and is configured, upon receipt of the drive force, to selectively move in a retract direction and an extend direction. The axial soft stop assembly is disposed within the actuator housing. The axial soft stop assembly is configured to be selectively engaged by the ball screw and, upon being engaged thereby, to translate, with compliance, a predetermined distance in the extend direction, and to prevent further movement of the ball screw upon translating the predetermined distance.

  6. Expandable intramedullary nails for fixation of tibial shaft fractures.

    PubMed

    Ghafil, Dior; Ackerman, Pieter; Baillon, Renaud; Verdonk, Rene; Delince, Philippe

    2012-12-01

    Interlocking intramedullary nailing is currently the preferred treatment for most tibial fractures requiring operative treatment, with good results and a relatively low complication rate as reported in large clinical series. However, vascular and neurological complications caused by interlocking screws have been reported. In addition, insertion of distal interlocking screws can be technically demanding and may entail substantial exposure. We present the results with an expandable self-locking nail in the management of 52 AO type A and B tibial shaft fractures. The mean time to union was 15.8 weeks and the rate of union was 98%. The average surgical time was 60 minutes. Complications were those usually seen in diaphysis nailing and no complication was noted during nail expansion. Interlocking screws are not necessary, which reduces the risk of iatrogenic lesions. The expandable nail allows effective management of AO type A and B diaphyseal fractures of the tibia, a lower radiation exposure and shorter operative time.

  7. Asymmetric distribution in twin screw granulation.

    PubMed

    Chan Seem, Tim; Rowson, Neil A; Gabbott, Ian; de Matas, Marcel; Reynolds, Gavin K; Ingram, Andy

    2016-09-01

    Positron Emission Particle Tracking (PEPT) was successfully employed to validate measured transverse asymmetry in material distribution in the conveying zones of a Twin Screw Granulator (TSG). Flow asymmetry was established to be a property of the granulator geometry and dependent on fill level. The liquid distribution of granules as a function of fill level was determined. High flow asymmetry at low fill level negatively affects granule nucleation leading to high variance in final uniformity. Wetting of material during nucleation was identified as a critical parameter in determining final granule uniformity and fill level is highlighted as a crucial control factor in achieving this. Flow asymmetry of dry material in conveying zones upstream of binder fluid injection leads to poor non-uniform wetting at nucleation and results in heterogeneous final product. The granule formation mechanism of 60°F kneading blocks is suggested to be primarily breakage of agglomerates formed during nucleation. Optimisation of screw configuration would be required to provide secondary growth. This work shows how fill dependent flow regimes affect granulation mechanisms.

  8. Minimally-invasive internal fixation of extra-articular distal femur fractures using a locking plate: tricks of the trade.

    PubMed

    Ehlinger, M; Adam, P; Abane, L; Arlettaz, Y; Bonnomet, F

    2011-04-01

    Fractures of the distal femur are rare and occur in two distinct population categories: young patients after high energy traumas and elderly patients who fall from their full height, and often carry severe co-morbidities making especially difficult to manage theses complex injuries. In elderly patients the potential complications are numerous including infection, non-union and frequent function deterioration. We present a technique of minimally invasive internal fixation of the distal extra-articular femur using a locking plate and present the tricks of the trade to obtain successful reduction and achieve union. The hardware used includes plate fixation with a large fragment locking screw. This minimally invasive surgery combines stability of the internal fixation device with the principles of closed surgery, allowing early mobilization and immediate weight bearing to warrant good functional recovery.

  9. [Management of Odontoid Fractures with Compression Screw and Anterior Transarticular Screw Fixation in Elderly Patients].

    PubMed

    Kočiš, J; Kelbl, M; Veselý, R; Kočiš, T

    2017-01-01

    PURPOSE OF THE STUDY In the management of dens axis fractures in patients older than 65 years of age the posterior approach is preferred due to osteoporosis and the risk of a failure of anterior osteosynthesis. The posterior approach, however, is associated with a higher incidence of complications. A combination of anterior transarticular fixation of C1/2 (ATS) with compression osteosynthesis of dens axis significantly increases the stability of osteosynthesis. MATERIAL AND METHODS In the period from 2009 to 2015 our hospital admitted 13 patients older than 65 years of age with a diagnosed type III dens axis fracture based on AO classification. 8 patients sustained a dens axis fracture combined with a stable atlas fracture. The cohort consisted of 13 women aged 67 to 90 years, with the mean age of 82.3 years. None of the female patients were affected neurologically. The dens axis fracture was treated by anterior approach. Once the screw was inserted in the dens axis, two more screws were added, the entrance points of those screws were medial and lateral to the odontoid screw and direction was divergently via C1/2 joints in order to reinforce stability. The patients were monitored at 6-week, 3-, 6- and 12-month follow-ups. Bone healing was confirmed by CT scan. RESULTS No complications were recorded during the surgery in any of the 13 patients. In one female patient the stabilization failed in the early postoperative period. A reoperation from anterior approach with the use of the same method was necessary. In eleven patients bone healing occurred after 6 to 12 months. In two patients pseudoarthrosis was formed with no clinical symptoms. No neurological deterioration or a patient s death was reported in the monitored period within 12 months after the treatment. DISCUSSION Where dens axis fractures in elderly patients are managed operatively, the posterior approach and transarticular fixation of C1/2 with sublaminar loop are preferred. This procedure is considered

  10. Genetics Home Reference: distal hereditary motor neuropathy, type II

    MedlinePlus

    ... distal hereditary motor neuropathy, type II distal hereditary motor neuropathy, type II Enable Javascript to view the ... PDF Open All Close All Description Distal hereditary motor neuropathy, type II is a progressive disorder that ...

  11. Elbow dislocation with ipsilateral distal radius fracture

    PubMed Central

    Meena, Sanjay; Trikha, Vivek; Kumar, Rakesh; Saini, Pramod; Sambharia, Abhishek Kumar

    2013-01-01

    Elbow dislocation associated with ipsilateral distal radius fracture is a rare pattern of injury, although it is common for elbow dislocation and forearm fractures to occur separately. We report a rare case of a 20-year-old male who had a posterior elbow dislocation and ipsilateral distal radius fracture. Elbow dislocation was first reduced in extension and distal radius fracture was then reduced in flexion. Both the injuries were conservatively managed. At 6 months follow-up, the patient had no pain in his elbow and minimal pain in his wrist on heavy lifting and had resumed his work as a laborer. PMID:24082758

  12. Elbow dislocation with ipsilateral distal radius fracture.

    PubMed

    Meena, Sanjay; Trikha, Vivek; Kumar, Rakesh; Saini, Pramod; Sambharia, Abhishek Kumar

    2013-07-01

    Elbow dislocation associated with ipsilateral distal radius fracture is a rare pattern of injury, although it is common for elbow dislocation and forearm fractures to occur separately. We report a rare case of a 20-year-old male who had a posterior elbow dislocation and ipsilateral distal radius fracture. Elbow dislocation was first reduced in extension and distal radius fracture was then reduced in flexion. Both the injuries were conservatively managed. At 6 months follow-up, the patient had no pain in his elbow and minimal pain in his wrist on heavy lifting and had resumed his work as a laborer.

  13. Management of Complications of Distal Radius Fractures

    PubMed Central

    Chung, Kevin C.; Mathews, Alexandra L.

    2015-01-01

    Synopsis Treating a fracture of the distal radius may require the surgeon to make a difficult decision between surgical treatment and nonsurgical management. The use of surgical fixation has recently increased owing to complications associated with conservative treatment. However, conservative action may be necessary depending on certain patient factors. The treating surgeon must be aware of the possible complications associated with distal radius fracture treatments to prevent their occurrence. Prevention can be achieved with a proper understanding of the mechanism of these complications. This article discusses the most recent evidence on how to manage and prevent complications following a fracture of the distal radius. PMID:25934197

  14. Semiconstrained Distal Radioulnar Joint Prosthesis

    PubMed Central

    Savvidou, Christiana; Murphy, Erin; Mailhot, Emilie; Jacob, Shushan; Scheker, Luis R.

    2013-01-01

    Distal radioulnar joint (DRUJ) problems can occur as a result of joint instability, abutment, or incongruity. The DRUJ is a weight-bearing joint; the ulnar head is frequently excised either totally or partially, and in some cases it is fused, because of degenerative, rheumatoid, or posttraumatic arthritis. Articles about these procedures report the ability to pronate and supinate, but they rarely discuss grip strength, and even less do they address lifting capacity. We report the long term results of the first 35 patients who underwent total DRUJ arthroplasty with the Aptis DRUJ prosthesis after 5 years follow-up. Surgical indications were all causes of dysfunctional DRUJ (degenerative, posttraumatic, autoimmune, congenital). We recorded data for patient demographics, range of motion (ROM), strength, and lifting capacity of the operated and of the nonoperated extremity. Pain and functional assessments were also recorded. The Aptis DRUJ prosthesis, a bipolar self-stabilizing DRUJ endoprosthesis that restores forearm function, consists of a semiconstained and modular implant designed to replace the function of the ulnar head, the sigmoid notch of the radius, and the triangular fibrocartilage ligaments. The surgical technique is presented in detail. The majority of the patients regained adequate ROM and improved their strength and lifting capacity to the operated side. Pain and activities of daily living were improved. Twelve patients experienced complications, most commonly being extensor carpi ulnaris (ECU) tendinitis, ectopic bone formation, bone resorption with stem loosening, low-grade infection, and need for ball replacement. The Aptis total DRUJ replacement prosthesis is an alternative to salvage procedures that enables a full range of motion as well as the ability to grip and lift weights encountered in daily living activities. PMID:24436788

  15. Economics of water injected air screw compressor systems

    NASA Astrophysics Data System (ADS)

    Venu Madhav, K.; Kovačević, A.

    2015-08-01

    There is a growing need for compressed air free of entrained oil to be used in industry. In many cases it can be supplied by oil flooded screw compressors with multi stage filtration systems, or by oil free screw compressors. However, if water injected screw compressors can be made to operate reliably, they could be more efficient and therefore cheaper to operate. Unfortunately, to date, such machines have proved to be insufficiently reliable and not cost effective. This paper describes an investigation carried out to determine the current limitations of water injected screw compressor systems and how these could be overcome in the 15-315 kW power range and delivery pressures of 6-10 bar. Modern rotor profiles and approach to sealing and cooling allow reasonably inexpensive air end design. The prototype of the water injected screw compressor air system was built and tested for performance and reliability. The water injected compressor system was compared with the oil injected and oil free compressor systems of the equivalent size including the economic analysis based on the lifecycle costs. Based on the obtained results, it was concluded that water injected screw compressor systems could be designed to deliver clean air free of oil contamination with a better user value proposition than the oil injected or oil free screw compressor systems over the considered range of operations.

  16. Midline Lumbar Fusion with Cortical Bone Trajectory Screw

    PubMed Central

    MIZUNO, Masaki; KURAISHI, Keita; UMEDA, Yasuyuki; SANO, Takanori; TSUJI, Masanori; SUZUKI, Hidenori

    2014-01-01

    A novel cortical bone trajectory (CBT) screw technique provides an alternative fixation technique for lumbar spine. Trajectory of CBT screw creates a caudo-cephalad path in sagittal plane and a medio-lateral path in axial plane, and engages cortical bone in the pedicle. The theoretical advantage is that it provides enhanced screw grip and interface strength. Midline lumbar fusion (MIDLF) is composed of posterior mid-line approach, microsurgical laminectomy, and CBT screw fixation. We adopted the MIDLF technique for lumbar spondylolisthesis. Advantages of this technique include that decompression and fusion are available in the same field, and it minimizes approach-related damages. To determine whether MIDLF with CBT screw is as effective as traditional approach and it is minimum invasive technique, we studied the clinical and radiological outcomes of MIDLF. Our results indicate that MIDLF is effective and minimum invasive technique. Evidence of effectiveness of MIDLF is that patients had good recovery score, and that CBT screw technique was safety in clinical and stable in radiological. MIDLF with CBT screw provides the surgeon with additional options for fixation. This technique is most likely to be useful for treating lumbar spondylolisthesis in combination with midline decompression and insertion of an interbody graft, such as the transforaminal lumbar interbody fusion or posterior lumbar interbody fusion techniques. PMID:25169139

  17. Scaphoid Proximal Pole Fracture Following Headless Screw Fixation

    PubMed Central

    Rancy, Schneider K.; Zelken, Jonathan A.; Lipman, Joseph D.; Wolfe, Scott W.

    2015-01-01

    Background Headless screw fixation of scaphoid fractures and nonunions yields predictably excellent outcomes with a relatively low complication profile. However, intramedullary implants affect the load to failure and stress distribution within bone and may be implicated in subsequent fracture. Case Description We describe a posttraumatic fracture pattern of the scaphoid proximal pole originating at the previous headless screw insertion site in three young male patients with healed scaphoid nonunions. Each fracture was remarkably similar in shape and size, comprised the volar proximal pole, and was contiguous with the screw entry point. Treatment was challenging but successful in all cases. Literature Review Previous reports have posited that stress-raisers secondary to screw orientation may be implicated in subsequent peri-implant fracture of the femoral neck. Repeat scaphoid fracture after screw fixation has also been reported. However, the shape and locality of secondary fracture have not been described, nor has the potential role of screw fixation in the production of distinct fracture patterns. Clinical Relevance Hand surgeons must be aware of this difficult complication that may follow antegrade headless screw fixation of scaphoid fracture nonunion, and of available treatment strategies. PMID:26855840

  18. Fracture mechanisms of retrieved titanium screw thread in dental implant.

    PubMed

    Yokoyama, Ken'ichi; Ichikawa, Tetsuo; Murakami, Hiroki; Miyamoto, Youji; Asaoka, Kenzo

    2002-06-01

    Titanium and its alloy are increasingly attracting attention for use as biomaterials. However, delayed fracture of titanium dental implants has been reported, and factors affecting the acceleration of corrosion and fatigue have to be determined. The fractured surface of a retrieved titanium screw and metallurgical structures of a dental implant system were analyzed. The outer surface of the retrieved screw had a structure different from that of the as-received screw. It was confirmed that a shear crack initiated at the root of the thread and propagated into the inner section of the screw. Gas chromatography revealed that the retrieved screw had absorbed a higher amount of hydrogen than the as-received sample. The grain structure of a titanium screw, immersed in a solution known to induce hydrogen absorption, showed features similar to those of the retrieved screw. It was concluded that titanium in a biological environment absorbs hydrogen and this may be the reason for delayed fracture of a titanium implant.

  19. Optically driven Archimedes micro-screws for micropump applications: multiple blade design

    NASA Astrophysics Data System (ADS)

    Baldeck, Patrice L.; Lin, Chih-Lang; Lin, Yu-Sheng; Lin, Chin-Te; Chung, Tien-Tung; Bouriau, Michel; Vitrant, Guy

    2011-10-01

    We study the rotation of photo-driven Archimedes screw with multiple blades. The micron-sized Archimedes screws are readily made by the two-photon polymerization technique. Free-floating screws that are trapped by optical tweezers align in the laser irradiation direction, and rotate spontaneously. In this study we demonstrate that the rotation speeds of two-blade-screws is twice the rotation speed of one-blade-screw. However, more complex 3-blade-screws rotate slower than 2-blade-screws due to their limited geometry resolution at this micron scale.

  20. Vibration analysis of three-screw pumps under pressure loads and rotor contact forces

    NASA Astrophysics Data System (ADS)

    Li, Wanyou; Lu, Hanfeng; Zhang, Yue; Zhu, Chuan; Lu, Xiqun; Shuai, Zhijun

    2016-01-01

    Two main vibration sources in three-screw pumps, the fluid exciting force and the screw contact force, are studied to provide the basis for vibration control in this paper. A fluid exciting force model and a screw contact model are proposed to calculate these forces. An experimental test is carried out to obtain the vibration response of a three-screw pump. A calibrated finite element model of the three-screw pump is used to verify the vibration response under the fluid exciting force and the screw contact force obtained from the proposed models. The results show that the screw contact force is more dominant than the fluid exciting force.

  1. Villous adenoma of the distal appendix.

    PubMed

    Taylor, J V; Thomas, M G; Kelly, S; Sutton, R

    1997-04-01

    Villous adenoma confined to the distal appendix has not been previously reported in conjunction with acute apendicitis. The presence of an adenoma indicates a need for further investigation due to an association with neoplasia elsewhere.

  2. Genetics Home Reference: Laing distal myopathy

    MedlinePlus

    ... Laing distal myopathy is a condition that affects skeletal muscles, which are muscles that the body uses for ... in heart (cardiac) muscle and in type I skeletal muscle fibers. Type I fibers, which are also known ...

  3. Estimating Driver Risk Using Alcohol Biomarkers, Interlock BAC Tests and Psychometric Assessments: Initial Descriptives

    PubMed Central

    Marques, Paul; Tippetts, Scott; Allen, John; Javors, Martin; Alling, Christer; Yegles, Michel; Pragst, Fritz; Wurst, Friedrich

    2009-01-01

    Aim To identify alcohol biomarker and psychometric measures that relate to drivers’ blood alcohol concentration (BAC) patterns from ignition interlock devices (IIDs). Design, Setting, Participants, Measurements In Alberta, Canada, 534 drivers, convicted of driving under the influence of alcohol (DUI), installed IIDs and agreed to participate in a research study. IID BAC tests are an established proxy for predicting future DUI convictions. Three risk groups were defined by rates of failed BAC tests. Program entry and followup blood samples (n=302, 171) were used to measure phosphatidyl ethanol (PETH), carbohydrate deficient transferrin (%CDT), gamma glutamyltransferase (GGT) and other biomarkers. Program entry urine (n=130) was analyzed for ethyl glucuronide (ETG) and ethyl sulfate (ETS). Entry hair samples were tested for fatty acid ethyl esters (FAEE) (n=92) and ETG (n=146). Psychometric measures included the DSM-4 Diagnostic Interview Schedule Alcohol Module, Alcohol Use Disorders Identification Test (AUDIT), the Timeline Followback (TLFB), the Drinker Inventory of Consequences (DRINC), and the Temptation and Restraint Inventory (TRI). Findings Except for FAEE, all alcohol biomarkers were significantly related to the interlock BAC test profiles; higher marker levels predicted higher rates of interlock BAC test failures. PETH, the strongest with an overall ANOVA F ratio of 35.5, had significant correlations with all nine of the other alcohol biomarkers and with 16 of 19 psychometric variables. Urine ETG and ETS were strongly correlated with the IID BAC tests. Conclusions The findings suggest several alcohol biomarkers and assessments could play an important role in the prediction and control of driver alcohol risk when relicensing. PMID:19922520

  4. Does plugging unused combination screw holes improve the fatigue life of fixation with locking plates in comminuted supracondylar fractures of the femur?

    PubMed

    Firoozabadi, R; McDonald, E; Nguyen, T-Q; Buckley, J M; Kandemir, U

    2012-02-01

    Filling the empty holes in peri-articular locking plates may improve the fatigue strength of the fixation. The purpose of this in vitro study was to investigate the effect of plugging the unused holes on the fatigue life of peri-articular distal femoral plates used to fix a comminuted supracondylar fracture model. A locking/compression plate was applied to 33 synthetic femurs and then a 6 cm metaphyseal defect was created (AO Type 33-A3). The specimens were then divided into three groups: unplugged, plugged with locking screw only and fully plugged holes. They were then tested using a stepwise or run-out fatigue protocol, each applying cyclic physiological multiaxial loads. All specimens in the stepwise group failed at the 770 N load level. The mean number of cycles to failure for the stepwise specimen was 25,500 cycles (SD 1500), 28,800 cycles (SD 6300), and 26,400 cycles (SD 2300) cycles for the unplugged, screw only and fully plugged configurations, respectively (p = 0.16). The mean number of cycles to failure for the run-out specimens was 42,800 cycles (SD 10,700), 36,000 cycles (SD 7200), and 36,600 cycles (SD 10,000) for the unplugged, screw only and fully plugged configurations, respectively (p = 0.50). There were also no differences in axial or torsional stiffness between the constructs. The failures were through the screw holes at the level of comminution. In conclusion, filling the empty combination locking/compression holes in peri-articular distal femur locking plates at the level of supracondylar comminution does not increase the fatigue life of the fixation in a comminuted supracondylar femoral fracture model (AO 33-A3) with a 6 cm gap.

  5. Insufficiency fracture at the distal diaphysis of the radius after synovectomy combined with the Sauvé-Kapandji procedure in a patient with rheumatoid arthritis.

    PubMed

    Nagira, Keita; Hagino, Hiroshi; Yamashita, Yasutsugu; Kishimoto, Yuji; Teshima, Ryota

    2010-10-01

    We report here a rare case of insufficiency fracture at the distal diaphysis of the radius in a patient with rheumatoid arthritis (RA) after synovectomy combined with the Sauvé-Kapandji procedure. A 71-year-old woman who had been diagnosed with RA had been consecutively treated with several disease-modifying antirheumatic drugs. She had undergone synovectomy of the right wrist combined with the Sauvé-Kapandji procedure, due to a tendon rupture, 2 years before the current presentation (first visit). Although she had not experienced any recent trauma, the wrist pain had increased after she had lifted up the bedding at the funeral of her friend about 1 month prior to her first visit. Radiographs of her right wrist taken at the second visit showed a fracture at the distal diaphysis of the radius at the level of the excision osteotomy of the distal ulna; however, no displacement of the distal fragment was observed. We immobilized her forearm in a long-arm cast. However, after 3 weeks of cast immobilization, a displacement of the distal fragment was observed. A manual reduction of the displacement was performed and the arm was again immobilized in a long-arm cast. However, 1 week later, a displaced distal fragment was again observed. Subsequently, she received an open reduction and internal fixation using a volar locking plate and screws with an autologous iliac crest bone graft. Bone union was completed by 8 months following the operation.

  6. Preliminary Design on Screw Press Model of Palm Oil Extraction Machine

    NASA Astrophysics Data System (ADS)

    Firdaus, Muhammad; Salleh, S. M.; Nawi, I.; Ngali, Z.; Siswanto, W. A.; Yusup, E. M.

    2017-01-01

    The concept of the screw press is to compress the fruit bunch between the main screw and travelling cones to extract the palm oil. Visual inspection, model development and simulation of screw press by using Solidworks 2016 and calculation of design properties were performed to support the investigation. The project aims to analyse different design of screw press which improves in reducing maintenance cost and increasing lifespan. The currently existing of screw press can endure between 500 to 900 hours and requires frequent maintenance. Different configurations have been tried in determination of best design properties in screw press. The results specify that screw press with tapered inner shaft has more total lifespan (hours) compared existing screw press. The selection of the screw press with tapered inner shaft can reduce maintenance cost and increase lifespan of the screw press.

  7. Spline-locking screw fastening strategy

    NASA Technical Reports Server (NTRS)

    Vranish, John M.

    1992-01-01

    A fastener was developed by NASA Goddard for efficiently performing assembly, maintenance, and equipment replacement functions in space using either robotics or astronaut means. This fastener, the 'Spline Locking Screw' (SLS) would also have significant commercial value in advanced space manufacturing. Commercial (or DoD) products could be manufactured in such a way that their prime subassemblies would be assembled using SLS fasteners. This would permit machines and robots to disconnect and replace these modules/parts with ease, greatly reducing life cycle costs of the products and greatly enhancing the quality, timeliness, and consistency of repairs, upgrades, and remanufacturing. The operation of the basic SLS fastener is detailed, including hardware and test results. Its extension into a comprehensive fastening strategy for NASA use in space is also outlined. Following this, the discussion turns toward potential commercial and government applications and the potential market significance of same.

  8. Spline-Locking Screw Fastening Strategy (SLSFS)

    NASA Technical Reports Server (NTRS)

    Vranish, John M.

    1991-01-01

    A fastener was developed by NASA Goddard for efficiently performing assembly, maintenance, and equipment replacement functions in space using either robotic or astronaut means. This fastener, the 'Spline Locking Screw' (SLS) would also have significant commercial value in advanced manufacturing. Commercial (or DoD) products could be manufactured in such a way that their prime subassemblies would be assembled using SLS fasteners. This would permit machines and robots to disconnect and replace these modules/parts with ease, greatly reducing life cycle costs of the products and greatly enhancing the quality, timeliness, and consistency of repairs, upgrades, and remanufacturing. The operation of the basic SLS fastener is detailed, including hardware and test results. Its extension into a comprehensive fastening strategy for NASA use in space is also outlined. Following this, the discussion turns toward potential commercial and government applications and the potential market significance of same.

  9. Spline-Screw Payload-Fastening System

    NASA Technical Reports Server (NTRS)

    Vranish, John M.

    1994-01-01

    Payload handed off securely between robot and vehicle or structure. Spline-screw payload-fastening system includes mating female and male connector mechanisms. Clockwise (or counter-clockwise) rotation of splined male driver on robotic end effector causes connection between robot and payload to tighten (or loosen) and simultaneously causes connection between payload and structure to loosen (or tighten). Includes mechanisms like those described in "Tool-Changing Mechanism for Robot" (GSC-13435) and "Self-Aligning Mechanical and Electrical Coupling" (GSC-13430). Designed for use in outer space, also useful on Earth in applications needed for secure handling and secure mounting of equipment modules during storage, transport, and/or operation. Particularly useful in machine or robotic applications.

  10. Analysis of Material Flow in Screw Extrusion of Aluminum

    SciTech Connect

    Haugen, Bjoern; Oernskar, Magnus; Welo, Torgeir; Wideroee, Fredrik

    2010-06-15

    Screw extrusion of aluminum is a new process for production of aluminum profiles. The commercial potential could be large. Little experimental and numerical work has been done with respect to this process.The material flow of hot aluminum in a screw extruder has been analyzed using finite element formulations for the non-Newtonian Navier-Stokes equations. Aluminum material properties are modeled using the Zener-Holloman material model. Effects of stick-slip conditions are investigated with respect to pressure build up and mixing quality of the extrusion process.The numerical results are compared with physical experiments using an experimental screw extruder.

  11. Noninvasive method for retrieval of broken dental implant abutment screw

    PubMed Central

    Gooty, Jagadish Reddy; Palakuru, Sunil Kumar; Guntakalla, Vikram Reddy; Nera, Mahipal

    2014-01-01

    Dental implants made of titanium for replacement of missing teeth are widely used because of ease of technical procedure and high success rate, but are not free of complications and may fail. Fracturing of the prosthetic screw continues to be a problem in restorative practice and great challenge to remove the fractured screw conservatively. This case report describes and demonstrates the technique of using an ultrasonic scaler in the removal of the fracture screw fragment as a noninvasive method without damaging the hex of implants. PMID:24963261

  12. Magnetic-field decay of three interlocked flux rings with zero linking number.

    PubMed

    Del Sordo, Fabio; Candelaresi, Simon; Brandenburg, Axel

    2010-03-01

    The resistive decay of chains of three interlocked magnetic flux rings is considered. Depending on the relative orientation of the magnetic field in the three rings, the late-time decay can be either fast or slow. Thus, the qualitative degree of tangledness is less important than the actual value of the linking number or, equivalently, the net magnetic helicity. Our results do not suggest that invariants of higher order than that of the magnetic helicity need to be considered to characterize the decay of the field.

  13. Successful Transcatheter Embolization of Penetrating Aortic Ulcer Using Interlocking Detachable Coils

    SciTech Connect

    Hama, Yukihiro; Kaji, Tatsumi; Iwasaki, Yoshie; Hinokiyama, Kazuhiro; Shimizu, Masafumi; Kusano, Shoichi

    2000-09-15

    A 54-year-old man with persistent chest pain was hospitalized for hypertension and DeBakey type IIIb aortic dissection. The false lumen of the dissection was almost completely thrombosed; however, a penetrating atherosclerotic ulcer (PAU) was observed 5 weeks later. At that time, we successfully embolized the PAU with a microcatheter and interlocking detachable coils (IDCs). The patient is well with no episodes of relapse in 20 months of follow-up. This case suggests the utility of the microcatheter and IDC system as an alternative to surgery.

  14. Ground-state kinetics of bistable redox-active donor-acceptor mechanically interlocked molecules.

    PubMed

    Fahrenbach, Albert C; Bruns, Carson J; Li, Hao; Trabolsi, Ali; Coskun, Ali; Stoddart, J Fraser

    2014-02-18

    The ability to design and confer control over the kinetics of theprocesses involved in the mechanisms of artificial molecular machines is at the heart of the challenge to create ones that can carry out useful work on their environment, just as Nature is wont to do. As one of the more promising forerunners of prototypical artificial molecular machines, chemists have developed bistable redox-active donor-acceptor mechanically interlocked molecules (MIMs) over the past couple of decades. These bistable MIMs generally come in the form of [2]rotaxanes, molecular compounds that constitute a ring mechanically interlocked around a dumbbell-shaped component, or [2]catenanes, which are composed of two mechanically interlocked rings. As a result of their interlocked nature, bistable MIMs possess the inherent propensity to express controllable intramolecular, large-amplitude, and reversible motions in response to redox stimuli. In this Account, we rationalize the kinetic behavior in the ground state for a large assortment of these types of bistable MIMs, including both rotaxanes and catenanes. These structures have proven useful in a variety of applications ranging from drug delivery to molecular electronic devices. These bistable donor-acceptor MIMs can switch between two different isomeric states. The favored isomer, known as the ground-state co-conformation (GSCC) is in equilibrium with the less favored metastable state co-conformation (MSCC). The forward (kf) and backward (kb) rate constants associated with this ground-state equilibrium are intimately connected to each other through the ground-state distribution constant, KGS. Knowing the rate constants that govern the kinetics and bring about the equilibration between the MSCC and GSCC, allows researchers to understand the operation of these bistable MIMs in a device setting and apply them toward the construction of artificial molecular machines. The three biggest influences on the ground-state rate constants arise from

  15. Effects on Subtalar Joint Stress Distribution After Cannulated Screw Insertion at Different Positions and Directions.

    PubMed

    Yuan, Cheng-song; Chen, Wan; Chen, Chen; Yang, Guang-hua; Hu, Chao; Tang, Kang-lai

    2015-01-01

    We investigated the effects on subtalar joint stress distribution after cannulated screw insertion at different positions and directions. After establishing a 3-dimensional geometric model of a normal subtalar joint, we analyzed the most ideal cannulated screw insertion position and approach for subtalar joint stress distribution and compared the differences in loading stress, antirotary strength, and anti-inversion/eversion strength among lateral-medial antiparallel screw insertion, traditional screw insertion, and ideal cannulated screw insertion. The screw insertion approach allowing the most uniform subtalar joint loading stress distribution was lateral screw insertion near the border of the talar neck plus medial screw insertion close to the ankle joint. For stress distribution uniformity, antirotary strength, and anti-inversion/eversion strength, lateral-medial antiparallel screw insertion was superior to traditional double-screw insertion. Compared with ideal cannulated screw insertion, slightly poorer stress distribution uniformity and better antirotary strength and anti-inversion/eversion strength were observed for lateral-medial antiparallel screw insertion. Traditional single-screw insertion was better than double-screw insertion for stress distribution uniformity but worse for anti-rotary strength and anti-inversion/eversion strength. Lateral-medial antiparallel screw insertion was slightly worse for stress distribution uniformity than was ideal cannulated screw insertion but superior to traditional screw insertion. It was better than both ideal cannulated screw insertion and traditional screw insertion for anti-rotary strength and anti-inversion/eversion strength. Lateral-medial antiparallel screw insertion is an approach with simple localization, convenient operation, and good safety.

  16. Long-term Bisphosphonate Therapy-induced Periprosthetic Femoral Stress Fracture in a Sliding Hip Screw Implant: A Unique Case Report

    PubMed Central

    Adams, Mark R; Dunn, Conor; Sirkin, Michael S; Reilly, Mark C

    2016-01-01

    Introduction: Long-term bisphosphonate therapy for osteoporosis is associated with an increased risk of low-to-no energy atypical subtrochanteric and femoral shaft fractures with characteristic radiologic findings. There are few reports of patients with long-term bisphosphonate-induced periprosthetic fractures, all of them had a hip arthroplasty prosthesis. In this report, we present a unique case of a 90-year-old Caucasian female on long-term bisphosphonate therapy with a sliding hip screw implant who sustained a periprosthetic fracture of the femoral shaft at the distal aspect of the plate. Case Report: In April 2014, a 90-year-old female presented with left thigh pain after a fall from standing height. She had a previous fixation of a left intertrochanteric hip fracture with a sliding hip screw in 1999 and a 9-year history of bisphosphonate therapy. Radiographs obtained in the emergency department revealed a left-sided femoral shaft fracture at the distal aspect of the previously applied five-hole side plate. Of note, the periprosthetic fracture demonstrated cortical thickening at the fracture site of the lateral femoral cortex, lack of comminution as well as a transverse appearance. The patient was taken to the operating room the next day for retrograde placement of an intramedullary nail of the left femur with revision of left intertrochanteric femur fracture fixation. By 3 months postoperatively, she had obtained full radiographic union. Conclusion: This case report highlights the possibility of an atypical fracture distal to the sliding hip screw implant after open reduction internal fixation of an intertrochanteric hip fracture in patients on long-term bisphosphonates. PMID:28164053

  17. Screw pumps cost effective for heavy crude operations

    SciTech Connect

    Brennan, J.R. )

    1992-12-21

    This paper reports that in petroleum production, screw pumps fulfill the requirements for pumping crude oil with an API gravity of 20[degrees] or less (0.93 sp gr or greater). In many cases, these pumps provide more efficiency than centrifugal and reciprocating pumps. Heavy crude oils typically have viscosities at pumping temperatures in excess of 500 SSU (100 cSt). While screw pumps can handle viscosities ranging from fractional centistokes to millions of centistokes, the normal range for crude oil, from cost and efficiency viewpoints, is above 100 SSU (20 cSt). Bitumens can also be handled by screw pumps. Invented in 1922, rotary, positive-displacement multiple-screw pumps have been used for pumping fuel for burning, lubricating oil, fluid power, process feed, food, chemicals, synthetic-fiber slurries, general transfer, and many other applications.

  18. 21. NBS SUIT LAB. THREE GLOVES, HELMET, AND SCREW DRIVER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. NBS SUIT LAB. THREE GLOVES, HELMET, AND SCREW DRIVER TORQUE WRENCH FOR ASSEMBLY AND REPAIR OF BOTH. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

  19. Hierarchical Porous Interlocked Polymeric Microcapsules: Sulfonic Acid Functionalization as Acid Catalysts

    PubMed Central

    Wang, Xiaomei; Gu, Jinyan; Tian, Lei; Zhang, Xu

    2017-01-01

    Owing to their unique structural and surface properties, mesoporous microspheres are widely applied in the catalytic field. Generally, increasing the surface area of the specific active phase of the catalyst is a good method, which can achieve a higher catalytic activity through the fabrication of the corresponding catalytic microspheres with the smaller size and hollow structure. However, one of the major challenges in the use of hollow microspheres (microcapsules) as catalysts is their chemical and structural stability. Herein, the grape-like hypercrosslinked polystyrene hierarchical porous interlocked microcapsule (HPIM-HCL-PS) is fabricated by SiO2 colloidal crystals templates, whose structure is the combination of open mouthed structure, mesoporous nanostructure and interlocked architecture. Numerous microcapsules assembling together and forming the roughly grape-like microcapsule aggregates can enhance the structural stability and recyclability of these microcapsules. After undergoing the sulfonation, the sulfonated HPIM-HCL-PS is served as recyclable acid catalyst for condensation reaction between benzaldehyde and ethylene glycol (TOF = 793 h−1), moreover, exhibits superior activity, selectivity and recyclability. PMID:28300062

  20. Interlocked graphene-Prussian blue hybrid composites enable multifunctional electrochemical applications.

    PubMed

    Zhang, Minwei; Hou, Chengyi; Halder, Arnab; Ulstrup, Jens; Chi, Qijin

    2017-03-15

    There has been increasing interest recently in mixed-valence inorganic nanostructure functionalized graphene composites, represented by Prussian blue, because they can cost-effectively apply to biosensors and energy devices. In this work, we present a one-pot green method to synthesize interlocked graphene-Prussian Blue hybrid composites as high-performance materials for biosensors and supercapacitor electrodes. Given the fact that graphene oxide (GO) can act as an electron acceptor, we used iron(II) and glucose as co-reducing agents to reduce GO under mild reaction conditions without introducing toxic agents. High quality Prussian blue nanocubes with no or little coordinated water were generated simultaneously. Reduced graphene oxide (rGO) was thus functionalized by Prussian blue nanocubes via chemical bonding to form a kind of interlocked microstructure with high stability and good conductivity. The as-synthesized composites were tested for biosensing of hydrogen peroxide (H2O2) and as supercapacitor electrode materials. The specific capacitance of the microcomposite based electrodes can reach 428Fg(-1), with good cycling stability. The microcomposite also displays high performance catalysis towards electroreduction of H2O2 with a high sensitivity of 1.5Acm(-2)M(-1).

  1. Mechanically Interlocked Linkers inside Metal-Organic Frameworks: Effect of Ring Size on Rotational Dynamics.

    PubMed

    Vukotic, V Nicholas; O'Keefe, Christopher A; Zhu, Kelong; Harris, Kristopher J; To, Christine; Schurko, Robert W; Loeb, Stephen J

    2015-08-05

    A series of metal-organic framework (MOF) materials has been prepared, each containing a mechanically interlocked molecule (MIM) as the linker and a copper(II) paddlewheel as the secondary building unit (SBU). The MIM linkers are [2]rotaxanes with varying sizes of crown ether macrocycles ([22]crown-6, 22C6; [24]crown-6, 24C6; [26]crown-6, 26C6; benzo[24]crown-6, B24C6) and an anilinium-based axle containing four carboxylate donor groups. Herein, the X-ray structures of MOFs UWCM-1 (no crown) and UWDM-1(22) are compared and demonstrate the effect of including a macrocycle around the axle of the linker. The rotaxane linkers are linear and result in nbo-type MOFs with void space that allows for motion of the interlocked macrocycle inside the MOF pores, while the macrocycle-free linker is bent and yields a MOF with a novel 12-connected bcc structure. Variable temperature (2)H solid-state nuclear magnetic resonance showed that the macrocycles in UWDM-1(22), UWDM-1(24), and UWDM-1(B24) undergo different degrees and rates of rotation depending on the size and shape of the macrocycle.

  2. Hierarchical Porous Interlocked Polymeric Microcapsules: Sulfonic Acid Functionalization as Acid Catalysts

    NASA Astrophysics Data System (ADS)

    Wang, Xiaomei; Gu, Jinyan; Tian, Lei; Zhang, Xu

    2017-03-01

    Owing to their unique structural and surface properties, mesoporous microspheres are widely applied in the catalytic field. Generally, increasing the surface area of the specific active phase of the catalyst is a good method, which can achieve a higher catalytic activity through the fabrication of the corresponding catalytic microspheres with the smaller size and hollow structure. However, one of the major challenges in the use of hollow microspheres (microcapsules) as catalysts is their chemical and structural stability. Herein, the grape-like hypercrosslinked polystyrene hierarchical porous interlocked microcapsule (HPIM-HCL-PS) is fabricated by SiO2 colloidal crystals templates, whose structure is the combination of open mouthed structure, mesoporous nanostructure and interlocked architecture. Numerous microcapsules assembling together and forming the roughly grape-like microcapsule aggregates can enhance the structural stability and recyclability of these microcapsules. After undergoing the sulfonation, the sulfonated HPIM-HCL-PS is served as recyclable acid catalyst for condensation reaction between benzaldehyde and ethylene glycol (TOF = 793 h‑1), moreover, exhibits superior activity, selectivity and recyclability.

  3. Screw thread parameter measurement system based on image processing method

    NASA Astrophysics Data System (ADS)

    Rao, Zhimin; Huang, Kanggao; Mao, Jiandong; Zhang, Yaya; Zhang, Fan

    2013-08-01

    In the industrial production, as an important transmission part, the screw thread is applied extensively in many automation equipments. The traditional measurement methods of screw thread parameter, including integrated test methods of multiparameters and the single parameter measurement method, belong to contact measurement method. In practical the contact measurement exists some disadvantages, such as relatively high time cost, introducing easily human error and causing thread damage. In this paper, as a new kind of real-time and non-contact measurement method, a screw thread parameter measurement system based on image processing method is developed to accurately measure the outside diameter, inside diameter, pitch diameter, pitch, thread height and other parameters of screw thread. In the system the industrial camera is employed to acquire the image of screw thread, some image processing methods are used to obtain the image profile of screw thread and a mathematics model is established to compute the parameters. The C++Builder 6.0 is employed as the software development platform to realize the image process and computation of screw thread parameters. For verifying the feasibility of the measurement system, some experiments were carried out and the measurement errors were analyzed. The experiment results show the image measurement system satisfies the measurement requirements and suitable for real-time detection of screw thread parameters mentioned above. Comparing with the traditional methods the system based on image processing method has some advantages, such as, non-contact, easy operation, high measuring accuracy, no work piece damage, fast error analysis and so on. In the industrial production, this measurement system can provide an important reference value for development of similar parameter measurement system.

  4. Backflow in twin-screw-type multiphase pump

    SciTech Connect

    Egashira, Kazuyuki; Shoda, Shinji; Tochikawa, Tetsuro; Furukawa, Akinori

    1998-02-01

    The performance of a twin-screw-type multiphase pump was investigated from the viewpoints of backflow in a gap along the twin-screw shafts and of scaleup parameters. Although both the backflow and the scaleup parameters have been recognized as important factors in developing multiphase pumps, they have not yet been clarified. The twin-screw pump was equipped with pressure sensors, set in the multiphase-test facility, and experimented with under various conditions to clarify the relationship between backflow rates and factors such as differential pressure, gas-void fractions (GVF`s), and the rotation speed of the shaft. A physical model was proposed with the empirical relationship of pressure distribution along the screw, and was successfully associated with scaleup parameters, such as the geometrical data of the twin-screw pump. Then it was used successfully to simulate the backflow in twin-screw pumps on relatively broad experimental conditions, judging from the comparison between the model and the experimental data.

  5. Isthmus-guided cortical bone trajectory for pedicle screw insertion.

    PubMed

    Iwatsuki, Koichi; Yoshimine, Toshiki; Ohnishi, Yu-ichiro; Ninomiya, Kosi; Ohkawa, Toshika

    2014-08-01

    Herein is described cortical bone trajectory (CBT), a new path for pedicle screw insertion for lumbar vertebral fusion. Because the points of insertion are under the end of the inferior articular process, and because the screws are inserted toward the lateral side, there is less soft tissue development than with the conventional technique; the CBT technique therefore enables less invasive surgery than the conventional technique. However, it has some drawbacks. For example, in the original CBT approach, the points of insertion are in the vicinity of the end of the inferior articular process. Because this joint has been destroyed in many patients who have indications for intervertebral fusion surgery, it is sometimes difficult to use it as a reference point for screw insertion location. With severe lateral slippage, the screw insertion site can become significantly dislocated sideways, with possible resultant damaging to the spinal canal and/or nerve root. The CBT technique here involved inserting the screws while keeping clear of the intervertebral foramen with the assistance of side view X-ray fluoroscopy and using the end of the inferior articular process and the isthmus as points of reference for screw location.

  6. Measurement of Tip Apex Distance and Migration of Lag Screws and Novel Blade Screw Used for the Fixation of Intertrochanteric Fractures

    PubMed Central

    Cheng, Cheng-Kung

    2017-01-01

    Fixation with a dynamic hip screw (DHS) is one of the most common methods for stabilizing intertrochanteric fractures, except for unstable and reverse oblique fracture types. However, failure is often observed in osteoporotic patients whereby the lag screw effectively ‘cuts out’ through the weak bone. Novel anti-migration blades have been developed to be used in combination with a lag screw (‘Blade Screw’) to improve the fixation strength in osteoporotic intertrochanteric fractures. An in-vitro biomechanical study and a retrospective clinical study were performed to evaluate lag screw migration when using the novel Blade Screw and a traditional threaded DHS. The biomechanical study showed both the Blade Screw and DHS displayed excessive migration (≥10 mm) before reaching 20,000 loading cycles in mild osteoporotic bone, but overall migration of the Blade Screw was significantly less (p ≤ 0.03). Among the patients implanted with a Blade Screw in the clinical study, there was no significant variation in screw migration at 3-months follow-up (P = 0.12). However, the patient’s implanted with a DHS did display significantly greater migration (P<0.001) than those implanted with the Blade Screw. In conclusion, the Blade Screw stabilizes the bone fragments during dynamic loading so as to provide significantly greater resistance to screw migration in patients with mild osteoporosis. PMID:28085930

  7. An analytical hierarchical model explaining the robustness and flaw-tolerance of the interlocking barb-barbule structure of bird feathers

    NASA Astrophysics Data System (ADS)

    Chen, Qiang; Gorb, Stanislav; Kovalev, Alexander; Li, Zhiyong; Pugno, Nicola

    2016-10-01

    Feathers can fulfill their aerodynamic function only if the pennaceous vane forms an airfoil stabilized by robust interlocking between barbules. Thus, revealing the robustness of the interlocking mechanical behavior of the barbules is very important to understand the function and long-term resilience of bird feathers. This paper, basing on the small- and large-beam deflection solutions, presents a hierarchical mechanical model for deriving the critical delamination conditions of the interlocking barbules between two adjacent barbs in bird feathers. The results indicate a high robustness and flaw-tolerant design of the structure. This work contributes to the understanding of the mechanical behavior of the robust interlocking barb-barbule structure of the bird feather, and provides a basis for design of feather-inspired materials with robust interlocking mechanism, such as advanced bio-inspired micro-zipping devices.

  8. Distal ligament in human glans: a comparative study of penile architecture.

    PubMed

    Hsu, Geng-Long; Lin, Chung-Wu; Hsieh, Cheng-Hsing; Hsieh, Ju-Ton; Chen, Shyh-Chyan; Kuo, Tzong-Fu; Ling, Pei-Ying; Huang, Hsiu-Mei; Wang, Chii-Jye; Tseng, Guo-Fang

    2005-01-01

    To elucidate the anatomic distal ligament of the human glans penis and associated clinical implications, we compared the structures of the glans penis and corpora cavernosa in dogs, rats, and humans. From May 2001 to March 2003, gross dissection, microscopic examinations, and stains for elastic fibers and collagen subtypes were made in the penises of 11 adult human male cadavers, 7 dogs, and 5 rats. A distal ligament in the human glans penis replaces the os penis that is present in dogs or rats, also termed the baculum, but retains collagen types I and III as common structural and interlocking components, respectively. The intercavernosal septum is complete, and intracavernosal pillars (ICPs) are abundant in dogs, absent in rats, and moderately developed in humans. A tunica with numerous elastic fibers exists to fulfill the requirements of erectile function in humans but not in dogs or rats, since it is essential for establishing tissue strength to serve as a buttress. We may conclude that in dogs and rats, the strong os penis is designed for ready intromission and is associated with a pair of well-developed nonelastic corpora to serve as a buttress for the os penis. These structures are necessary for the rigorous coitus observed in dogs. The less compliant corpus cavernosum is suitable for the flipping action observed in a mating male rat. These specific anatomic designs may provide explanations for the individual requirements for the specific physiologic functions that differ from species to species. Although there is no os in the human glans, a strong equivalent distal ligament is arranged centrally and acts as a supporting trunk for the glans penis. Without this important structure, the glans could be too weak to bear the buckling pressure generated during coitus and too limber to serve as a patent passage for ejaculation, and it could be too difficult to transmit the intracavernosal pressure surge along the entire penis during ejaculation. Given the common

  9. Sextant of Sapphires for Molar Distalization

    PubMed Central

    Palla, Yudistar Venkata; Ganugapanta, Vivek Reddy

    2016-01-01

    Introduction Space analysis quantifies the amount of crowding within the arches estimating the severity of space discrepancy. The space gaining procedures include extraction and non-extraction procedures like expansion, proximal stripping and molar distalization. Aim To identify features seen in molar distalization cases. Materials and Methods The sample size comprised 20 patients in whom molar distalization was decided as the treatment plan. The study models and lateral cephalograms of all the patients were taken. Occlusograms were obtained. Model analysis and cephalometric analysis were performed. Descriptive statistical analysis like mean, standard deviation, standard error and mode were done. Results The parameters in Question gave following results. The Bolton analysis showed anterior mandibular excess with mean value of 1.56mm±1.07. The first order discrepancy between maxillary central and lateral incisors was 5±1.95. The premolar rotation showed mean value of 16.58±5.12. The molar rotation showed the value of 7.66±2.26. The nasolabial angle showed the mean of 101.25±8.7 IMPA of 101.4±5.74. Conclusion The six features studied in molar distalization cases [First order discrepancy between upper central and lateral incisors; Rotation of premolars and molars; Bolton’s discrepancy in anterior dentition; Average to horizontal growth pattern; Proclined lower incisors and Obtuse nasolabial angle] can be taken as patterns seen in molar distalization cases and considered as a valid treatment plan. PMID:27656572

  10. Topographic matching of distal radius and proximal fibula articular surface for distal radius osteoarticular reconstruction.

    PubMed

    Zhang, H; Chen, S; Wang, Z; Guo, Y; Liu, B; Tong, D

    2016-07-01

    During osteoarticular reconstruction of the distal radius with the proximal fibula, congruity between the two articular surfaces is an important factor in determining the quality of the outcome. In this study, a three-dimensional model and a coordinate transformation algorithm were developed on computed tomography scanning. Articular surface matching was performed and parameters for the optimal position were determined quantitatively. The mean radii of best-fit spheres of the articular surfaces of the distal radius and proximal fibula were compared quantitatively. The radial inclination and volar tilt following reconstruction by an ipsilateral fibula graft, rather than the contralateral, best resembles the values of the native distal radius. Additionally, the ipsilateral fibula graft reconstructed a larger proportion of the distal radius articular surface than did the contralateral. The ipsilateral proximal fibula graft provides a better match for the reconstruction of the distal radius articular surface than the contralateral, and the optimal position for graft placement is quantitatively determined.

  11. Prediction of Deformity Correction by Pedicle Screw Instrumentation in Thoracolumbar Scoliosis Surgery

    NASA Astrophysics Data System (ADS)

    Kiriyama, Yoshimori; Yamazaki, Nobutoshi; Nagura, Takeo; Matsumoto, Morio; Chiba, Kazuhiro; Toyama, Yoshiaki

    In segmental pedicle screw instrumentation, the relationship between the combinations of pedicle screw placements and the degree of deformity correction was investigated with a three-dimensional rigid body and spring model. The virtual thoracolumbar scoliosis (Cobb’s angle of 47 deg.) was corrected using six different combinations of pedicle-screw placements. As a result, better correction in the axial rotation was obtained with the pedicle screws placed at or close to the apical vertebra than with the screws placed close to the end vertebrae, while the correction in the frontal plane was better with the screws close to the end vertebrae than with those close to the apical vertebra. Additionally, two screws placed in the convex side above and below the apical vertebra provided better correction than two screws placed in the concave side. Effective deformity corrections of scoliosis were obtained with the proper combinations of pedicle screw placements.

  12. Development and Testing of X-Ray Imaging-Enhanced Poly-L-Lactide Bone Screws

    PubMed Central

    Tzeng, Jy-Jiunn; Wu, Ting-Lin; Fong, Tsorng-Harn; Feng, Sheng-Wei; Huang, Haw-Ming

    2015-01-01

    Nanosized iron oxide particles exhibit osteogenic and radiopaque properties. Thus, iron oxide (Fe3O4) nanoparticles were incorporated into a biodegradable polymer (poly-L-lactic acid, PLLA) to fabricate a composite bone screw. This multifunctional, 3D printable bone screw was detectable on X-ray examination. In this study, mechanical tests including three-point bending and ultimate tensile strength were conducted to evaluate the optimal ratio of iron oxide nanoparticles in the PLLA composite. Both injection molding and 3D printing techniques were used to fabricate the PLLA bone screws with and without the iron oxide nanoparticles. The fabricated screws were implanted into the femoral condyles of New Zealand White rabbits. Bone blocks containing the PLLA screws were resected 2 and 4 weeks after surgery. Histologic examination of the surrounding bone and the radiopacity of the iron-oxide-containing PLLA screws were evaluated. Our results indicated that addition of iron oxide nanoparticles at 30% significantly decreased the ultimate tensile stress properties of the PLLA screws. The screws with 20% iron oxide exhibited strong radiopacity compared to the screws fabricated without the iron oxide nanoparticles. Four weeks after surgery, the average bone volume of the iron oxide PLLA composite screws was significantly greater than that of PLLA screws without iron oxide. These findings suggested that biodegradable and X-ray detectable PLLA bone screws can be produced by incorporation of 20% iron oxide nanoparticles. Furthermore, these screws had significantly greater osteogenic capability than the PLLA screws without iron oxide. PMID:26466309

  13. Development and Testing of X-Ray Imaging-Enhanced Poly-L-Lactide Bone Screws.

    PubMed

    Chang, Wei-Jen; Pan, Yu-Hwa; Tzeng, Jy-Jiunn; Wu, Ting-Lin; Fong, Tsorng-Harn; Feng, Sheng-Wei; Huang, Haw-Ming

    2015-01-01

    Nanosized iron oxide particles exhibit osteogenic and radiopaque properties. Thus, iron oxide (Fe3O4) nanoparticles were incorporated into a biodegradable polymer (poly-L-lactic acid, PLLA) to fabricate a composite bone screw. This multifunctional, 3D printable bone screw was detectable on X-ray examination. In this study, mechanical tests including three-point bending and ultimate tensile strength were conducted to evaluate the optimal ratio of iron oxide nanoparticles in the PLLA composite. Both injection molding and 3D printing techniques were used to fabricate the PLLA bone screws with and without the iron oxide nanoparticles. The fabricated screws were implanted into the femoral condyles of New Zealand White rabbits. Bone blocks containing the PLLA screws were resected 2 and 4 weeks after surgery. Histologic examination of the surrounding bone and the radiopacity of the iron-oxide-containing PLLA screws were evaluated. Our results indicated that addition of iron oxide nanoparticles at 30% significantly decreased the ultimate tensile stress properties of the PLLA screws. The screws with 20% iron oxide exhibited strong radiopacity compared to the screws fabricated without the iron oxide nanoparticles. Four weeks after surgery, the average bone volume of the iron oxide PLLA composite screws was significantly greater than that of PLLA screws without iron oxide. These findings suggested that biodegradable and X-ray detectable PLLA bone screws can be produced by incorporation of 20% iron oxide nanoparticles. Furthermore, these screws had significantly greater osteogenic capability than the PLLA screws without iron oxide.

  14. Arthroscopically assisted reduction and immobilization of intraarticular fracture of the distal end of the radius: several options of reduction and immobilization.

    PubMed

    Guofen, Chen; Doi, Kazuteru; Hattori, Yasunori; Kitajima, Izuru

    2005-06-01

    On the basis of preoperative computerized tomography scanning and newly developed 3-dimensional reconstruction technique, Doi classified intraarticular distal radial fracture to 2-, 3-, and 4-part type, according to the number of main fracture fragments in distal radial aspect. This classification system simply, as well as perspicuously, describes the status of joint surface, thereby providing an intuitionist and practical guideline for arthroscopy procedure. Between 1992 and 2003, 91 patients ranged from 21 to 79 years of age with intraarticular distal radius fracture were treated with an arthroscopically assisted operation at our department. Among these patients, 42, 34, and 15 cases were 2-, 3-, and 4-part type, accounting for 46%, 37%, and 17% respectively. Wrist arthroscopy was applied individually according to the different type, with the purpose of achieving <1mm reduction. Role of arthroscopy was postreduction examination for 14 cases, as K-wire guider in 13 cases, assisting reduction, and immobilization in 61 cases. Four of the 61 cases changed to ORIF. Immobilization methods include external fixator combined with K-wire or plate combined with pullout wire or screw. K-wire without other implant was applied to 6 cases. In 1 case, a screw was the only implant.

  15. The influence of screw configuration on the pretreatment performance of a continuous twin screw-driven reactor (CTSR).

    PubMed

    Choi, Chang Ho; Um, Byung-Hwan; Oh, Kyeong Keun

    2013-03-01

    A combination of a continuous twin screw-driven reactor (CTSR) and a dilute acid pretreatment was used for the pretreatment of biomass with a high cellulose content and high monomeric xylose hydrolyzate. With the newly modified CTSR screw configuration (Config. 3), the influences of the screw rotational speed (30-60 rpm), of the pretreatment conditions such as acid concentration (1-5%) and reaction temperature (160-175 °C) at the operating condition of biomass feeding rate (1.0 g/min) and acid feeding rate (13.4 mL/min) on the pretreatment performance were investigated. The cellulose content in the pretreated rape straw was 67.1% at the following optimal conditions: barrel temperature of 165 °C, acid concentration of 3.0% (w/v), and screw rotational speed of 30 rpm. According to the three screw configurations, the glucose yields from enzymatic hydrolysis were 70.1%, 72.9%, and 78.7% for screw Configs. 1, 2, and 3, respectively.

  16. Investigation of an 11mm diameter twin screw granulator: Screw element performance and in-line monitoring via image analysis.

    PubMed

    Sayin, Ridade; Martinez-Marcos, Laura; Osorio, Juan G; Cruise, Paul; Jones, Ian; Halbert, Gavin W; Lamprou, Dimitrios A; Litster, James D

    2015-12-30

    As twin screw granulation (TSG) provides one with many screw element options, characterization of each screw element is crucial in optimizing the screw configuration in order to obtain desired granule attributes. In this study, the performance of two different screw elements - distributive feed screws and kneading elements - was studied in an 11 mm TSG at different liquid-to-solid (L/S) ratios. The kneading element configuration was found to break large granules more efficiently, leading to narrower granule size distributions. While pharmaceutical industry shifts toward continuous manufacturing, inline monitoring and process control are gaining importance. Granules from an 11 mm TSG were analysed using the Eyecon™, a real-time high speed direct imaging system, which has been used to capture accurate particle size distribution and particle count. The size parameters and particle count were then assessed in terms of their ability to be a suitable control measure using the Shewhart control charts. d10 and particle count were found to be good indicators of the change in L/S ratio. However, d50 and d90 did not reflect the change, due to their inherent variability even when the process is at steady state.

  17. Osteochondritis of the Distal Tibial Epiphysis

    PubMed Central

    EL Hajj, Firass; Sebaaly, Amer; Kharrat, Khalil; Ghanem, Ismat

    2012-01-01

    Osteochondritis of the distal tibial epiphysis is a very rare entity. 9 cases have been described in 7 articles and 8 other cases have been mentioned in textbooks. This paper describes the 10th case of osteochondritis of the distal tibial epiphysis and summarizes the clinical and radiological presentations of the 9 other cases. The etiology of this entity is well debated in the literature. We believe that it results from a vascular abnormality in the distal tibial epiphysis associated with a mechanical stress (trauma, excessive overload, etc.). Since it is a self-limited disease, the prognosis is good and the younger the patient is the better the prognosis will be. In general, this entity responds well to conservative treatment. PMID:23193412

  18. Physeal arrest of the distal radius.

    PubMed

    Abzug, Joshua M; Little, Kevin; Kozin, Scott H

    2014-06-01

    Fractures of the distal radius are among the most common pediatric fractures. Although most of these fractures heal without complication, some result in partial or complete physeal arrest. The risk of physeal arrest can be reduced by avoiding known risk factors during fracture management, including multiple attempts at fracture reduction. Athletes may place substantial compressive and shear forces across the distal radial physes, making them prone to growth arrest. Timely recognition of physeal arrest can allow for more predictable procedures to be performed, such as distal ulnar epiphysiodesis. In cases of partial arrest, physeal bar excision with interposition grafting can be performed. Once ulnar abutment is present, more invasive procedures may be required, including ulnar shortening osteotomy or radial lengthening.

  19. Posterior arch C-1 screw technique: a cadaveric comparison study.

    PubMed

    Moisi, Marc; Fisahn, Christian; Tkachenko, Lara; Jeyamohan, Shiveindra; Reintjes, Stephen; Grunert, Peter; Norvell, Daniel C; Tubbs, R Shane; Page, Jeni; Newell, David W; Nora, Peter; Oskouian, Rod J; Chapman, Jens

    2017-03-17

    OBJECTIVE Posterior atlantoaxial stabilization and fusion using C-1 lateral mass screw fixation has become commonly used in the treatment of instability and for reconstructive indications since its introduction by Goel and Laheri in 1994 and modification by Harms in 2001. Placement of such lateral mass screws can be challenging because of the proximity to the spinal cord, vertebral artery, an extensive venous plexus, and the C-2 nerve root, which overlies the designated starting point on the posterior center of the lateral mass. An alternative posterior access point starting on the posterior arch of C-1 could provide a C-2 nerve root-sparing starting point for screw placement, with the potential benefit of greater directional control and simpler trajectory. The authors present a cadaveric study comparing an alternative strategy (i.e., a C-1 screw with a posterior arch starting point) to the conventional strategy (i.e., using the lower lateral mass entry site), specifically assessing the safety of screw placement to preserve the C-2 nerve root. METHODS Five US-trained spine fellows instrumented 17 fresh human cadaveric heads using the Goel/Harms C-1 lateral mass (GHLM) technique on the left and the posterior arch lateral mass (PALM) technique on the right, under fluoroscopic guidance. After screw placement, a CT scan was obtained on each specimen to assess for radiographic screw placement accuracy. Four faculty spine surgeons, blinded to the surgeon who instrumented the cadaver, independently graded the quality of screw placement using a modified Upendra classification. RESULTS Of the 17 specimens, the C-2 nerve root was anatomically impinged in 13 (76.5%) of the specimens. The GHLM technique was graded Type 1 or 2, which is considered "acceptable," in 12 specimens (70.6%), and graded Type 3 or 4 ("unacceptable") in 5 specimens (29.4%). In contrast, the PALM technique had 17 (100%) of 17 graded Type 1 or 2 (p = 0.015). There were no vertebral artery injuries found

  20. Pullout performance comparison of novel expandable pedicle screw with expandable poly-ether-ether-ketone shells and cement-augmented pedicle screws.

    PubMed

    Aycan, Mehmet Fatih; Tolunay, Tolga; Demir, Teyfik; Yaman, Mesut Emre; Usta, Yusuf

    2017-02-01

    Aim of this study is to assess the pullout performance of various pedicle screws in different test materials. Polyurethane foams (Grade 10 and Grade 40) produced in laboratory and bovine vertebrae were instrumented with normal, cannulated (cemented), novel expandable and normal (cemented) pedicle screws. Test samples were prepared according to the ASTM F543 standard testing protocols and surgical guidelines. To examine the screw placement and cement distribution, anteriosuperior and oblique radiographs were taken from each sample after insertion process was completed. Pullout tests were performed in an Instron 3369 testing device. Load versus displacement graphs were recorded and the ultimate pullout force was defined as the maximum load (pullout strength) sustained before failure of screw. Student's t-test was performed on each group whether the differences between pullout strength of pedicle screws were significant or not. While normal pedicle screws have the lowest pullout strength in all test materials, normal pedicle screws cemented with polymethylmethacrylate exhibit significantly higher pullout performance than others. For all test materials, there is a significant improvement in pullout strength of normal screws by augmentation. While novel expandable pedicle screws with expandable poly-ether-ether-ketone shells exhibited lower pullout performance than normal screws cemented with polymethylmethacrylate, their pullout performances in all groups were higher than the ones of normal and cannulated pedicle screws. For all test materials, although cannulated pedicle screws exhibit higher pullout strength than normal pedicle screws, there are no significant differences between the two groups. The novel expandable pedicle screws with expandable poly-ether-ether-ketone shells may be used instead of normal and cannulated pedicle screws cemented with polymethylmethacrylate due to their good performances.

  1. Accuracy of pedicle screw placement using intraoperative neurophysiological monitoring and computed tomography.

    PubMed

    Mavrogenis, Andreas F; Papagelopoulos, Panayiotis J; Korres, Demetrios S; Papadopoulos, Konstantinos; Sakas, Damianos E; Pneumaticos, Spiros

    2009-01-01

    Fifty consecutive patients with posterior thoracolumbar spine fusion were included in a prospective study to determine the accuracy of intraoperative neurophysiological monitoring (IONM) for safe pedicle screw placement using postoperative computed tomography (CT). The patients were allocated into two equal groups. Pedicle screw placement was evaluated intraoperatively by using the image intensifier. In group A, the integrity of the pedicle wall was evaluated intraoperatively with monopolar stimulation of each screw head with a hand-held single-tip stimulator; the compound muscle action potentials were recorded. A constant current threshold of 7 mA was considered indicative of pedicle breach; < 7 mA was considered as direct contact with neural elements, and > 7mA was considered normal. In group B, pedicle screw placement was performed without IONM. Overall, 306 pedicle screws were inserted in both groups. Postoperatively, all patients underwent CT scans of the spine to evaluate pedicle screw placement. Intraoperatively, five screws in respective group A patients had to be repositioned after IONM (threshold of < 7 mA); in these patients, postoperative CT scans showed proper screw placement. Postoperative CT scans showed eight misdirected screws; two screws (1.26%) in group A patients and six screws (4%) in group B patients. Two screws were misdirected through the medial pedicle wall and six screws were misdirected through the lateral pedicle wall. Both medially misdirected screws were observed in group B patients (1.35%); these patients developed neurologic symptoms postoperatively and underwent revision surgery, with redirection of the misdirected screws and subsequent resolution of the neurologic symptoms. Two of the six laterally misdirected screws were observed in group A patients (1.26%); the remaining four laterally misdirected screws were observed in group B patients (2.7%). None of these patients had neurologic sequelae; no revision surgery was required. The

  2. [Late outcome of Kapandji-Sauvé distal radio-ulnar arthrodesis].

    PubMed

    Welk, E; Martini, A K

    1998-11-01

    In a retrospective study the outcome of patients treated by the Kapandji-Sauvé procedure was evaluated. In the period from 1989 to 1993, 18 patients were operated. The arthrodesis of the distal radioulnar joint was performed by a dorsoulnar incision using one screw. A 2 cm long segment of the ulna was resected. Indications for Kapandji-Sauvé procedures were in 12 cases deformities subsequent to wrist fractures, in three cases osteoarthrosis of the distal radioulnar joint, in two cases Madelung's deformity and in one case Kienböck's disease. The mean follow-up time was 5.1 years (range 3 to 7 years). There was one case of reossification, which required reoperation. No other complications were seen. An excellent result was obtained in seven patients, a good result in nine patients, one patient showed satisfactory and one poor results. Grip strength was normal in six cases, reduced up to 20% in seven cases and reduced up to 50% in five cases. 13 patients returned to their previous occupation. 12 patients showed a range of pronation-supination of more than 150 degrees. There was no correlation between X-ray findings and clinical outcome in patients.

  3. Helical Screw Expander Evaluation Project. Final report

    SciTech Connect

    McKay, R.

    1982-03-01

    A functional 1-MW geothermal electric power plant that featured a helical screw expander was produced and then tested in Utah in 1978 to 1979 with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing operation on two-phase geothermal fluids. The Project also produced a computer-equipped data system, an instrumentation and control van, and a 1000-kW variable load bank, all integrated into a test array designed for operation at a variety of remote test sites. Additional testing was performed in Mexico in 1980 under a cooperative test program using the same test array, and machine efficiency was measured at 62% maximum with the rotors partially coated with scale, compared with approximately 54% maximum in Utah with uncoated rotors, confirming the importance of scale deposits within the machine on performance. Data are presented for the Utah testing and for the noncondensing phases of the testing in Mexico. Test time logged was 437 hours during the Utah tests and 1101 hours during the Mexico tests.

  4. Torsion of wandering spleen and distal pancreas

    SciTech Connect

    Sheflin, J.R.; Lee, C.M.; Kretchmar, K.A.

    1984-01-01

    Wandering spleen is the term applied to the condition in which a long pedicle allows the spleen to lie in an abnormal location. Torsion of a wandering spleen is an unusual cause of an acute abdomen and is rarely diagnosed preoperatively. Associated torsion of the distal pancreas is even more uncommon. The authors describe a patient with torsion of a wandering spleen and distal pancreas, who was correctly diagnosed, and define the merits of the imaging methods used. The initial examination should be /sup 99//sup m/Tc-sulfur colloid liner-spleen scanning.

  5. Contemporary Management of Primary Distal Urethral Cancer.

    PubMed

    Traboulsi, Samer L; Witjes, Johannes Alfred; Kassouf, Wassim

    2016-11-01

    Primary urethral cancer is one of the rare urologic tumors. Distal urethral tumors are usually less advanced at diagnosis compared with proximal tumors and have a good prognosis if treated appropriately. Low-stage distal tumors can be managed successfully with a surgical approach in men or radiation therapy in women. There are no clear-cut indications for the choice of the most appropriate treatment modality. Organ-preserving modalities have shown effective and should be used whenever they do not compromise the oncological safety to decrease the physical and psychological trauma of dismemberment or loss of sexual/urinary function.

  6. Reconstruction of the Distal Oblique Bundle of the Interosseous Membrane: A Technique to Restore Distal Radioulnar Joint Stability.

    PubMed

    Riggenbach, Michael D; Wright, Thomas W; Dell, Paul C

    2015-11-01

    The distal radioulnar ligament reconstruction is a technique that may be used for distal radioulnar joint instability without arthritis and failed nonsurgical management; clinical results demonstrate resolved or improved stability. Recent literature has focused on the distal oblique bundle of the interosseous membrane and its contributions to stability. This article describes a technically simple surgical technique to reconstruct the distal oblique bundle and restore distal radioulnar joint stability.

  7. Interlocking Toy Building Blocks as Hands-On Learning Modules for Blind and Visually Impaired Chemistry Students

    ERIC Educational Resources Information Center

    Melaku, Samuel; Schreck, James O.; Griffin, Kameron; Dabke, Rajeev B.

    2016-01-01

    Interlocking toy building blocks (e.g., Lego) as chemistry learning modules for blind and visually impaired (BVI) students in high school and undergraduate introductory or general chemistry courses are presented. Building blocks were assembled on a baseplate to depict the relative changes in the periodic properties of elements. Modules depicting…

  8. 49 CFR 236.401 - Automatic block signal system and interlocking standards applicable to traffic control systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... standards applicable to traffic control systems. 236.401 Section 236.401 Transportation Other Regulations... TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Traffic Control Systems Standards § 236.401 Automatic block signal system and interlocking standards applicable to traffic control systems. The...

  9. 49 CFR 236.401 - Automatic block signal system and interlocking standards applicable to traffic control systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... standards applicable to traffic control systems. 236.401 Section 236.401 Transportation Other Regulations... TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Traffic Control Systems Standards § 236.401 Automatic block signal system and interlocking standards applicable to traffic control systems. The...

  10. Institutional Conflict of Interest: The Role of Interlocking Directorates in the Scientific Relationships between Universities and the Corporate Sector

    ERIC Educational Resources Information Center

    Slaughter, Sheila; Thomas, Scott L.; Johnson, David R.; Barringer, Sondra N.

    2014-01-01

    We examined the potential for institutional conflict of interest between the 26 private universities belonging to the Association of American Universities and the corporations to which they are tied through their boards of trustees. We were interested in the degree to which interlocks may have tightened over three points across an 11-year period…

  11. Paper-Based Triboelectric Nanogenerators Made of Stretchable Interlocking Kirigami Patterns.

    PubMed

    Wu, Changsheng; Wang, Xin; Lin, Long; Guo, Hengyu; Wang, Zhong Lin

    2016-04-26

    The development of stretchable energy generation devices is indispensable for achieving stretchable, self-powered electronic systems. In this paper, a type of highly stretchable triboelectric nanogenerators made from conventional, inelastic materials such as paper is presented. It exploits a rationally designed interlocking kirigami structure and is capable of harvesting energy from various types of motions such as stretching, pressing, and twisting owing to the shape-adaptive thin film design. Energy harvested from the as-fabricated devices has been used for powering an LCD screen and lighting LED arrays. Furthermore, the paper-based devices have also been demonstrated for self-powered acceleration sensing and self-powered sensing of book opening and closing. This work introduces traditional kirigami into the development of stretchable triboelectric nanogenerators and verifies its promising applications in both power generation and self-powered sensing.

  12. D0 Central Tracking Solenoid Energizatino, Controls, Interlocks and Quench Protection Initial Validation Procedures

    SciTech Connect

    Jaskierny, W.; Hance, R.; /Fermilab

    1998-01-27

    This note presents the inspection and tests to be performed on the DZERO solenoid energization, controls, interlocks and quench protection system before it is energized for the first time. This test is to be performed with a 5000A jumper at the end of the bus instead of the solenoid. This system is based in DZERO room 511. A copy of this note shall be annotated, signed and dated by the person coordinating the procedure; and filed with the system maintenance records. Annotations shall include comments about any aspect of the procedure that is abnormal or unsuccessful. The following inspections and tests shall be performed by persons knowledgeable about the system. Each individual test step should be reviewed and understood before proceeding with that step.

  13. The Community Structure of the European Network of Interlocking Directorates 2005–2010

    PubMed Central

    Heemskerk, Eelke M.; Daolio, Fabio; Tomassini, Marco

    2013-01-01

    The boards of directors at large European companies overlap with each other to a sizable extent both within and across national borders. This could have important economic, political and management consequences. In this work we study in detail the topological structure of the networks that arise from this phenomenon. Using a comprehensive information database, we reconstruct the implicit networks of shared directorates among the top 300 European firms in 2005 and 2010, and suggest a number of novel ways to explore the trans-nationality of such business elite networks. Powerful community detection heuristics indicate that geography still plays an important role: there exist clear communities and they have a distinct national character. Nonetheless, from 2005 to 2010 we observe a densification of the boards interlocks network and a larger transnational orientation in its communities. Together with central actors and assortativity analyses, we provide statistical evidence that, at the level of corporate governance, Europe is getting closer. PMID:23894318

  14. DNA Entry into and Exit out of the Cohesin Ring by an Interlocking Gate Mechanism.

    PubMed

    Murayama, Yasuto; Uhlmann, Frank

    2015-12-17

    Structural maintenance of chromosome (SMC) complexes are proteinaceous rings that embrace DNA to enable vital chromosomal functions. The ring is formed by two SMC subunits, closed at a pair of ATPase heads, whose interaction is reinforced by a kleisin subunit. Using biochemical analysis of fission-yeast cohesin, we find that a similar series of events facilitates both topological entrapment and release of DNA. DNA-sensing lysines trigger ATP hydrolysis to open the SMC head interface, whereas the Wapl subunit disengages kleisin, but only after ATP rebinds. This suggests an interlocking gate mechanism for DNA transport both into and out of the cohesin ring. The entry direction is facilitated by a cohesin loader that appears to fold cohesin to expose the DNA sensor. Our results provide a model for dynamic DNA binding by all members of the SMC family and explain how lysine acetylation of cohesin establishes enduring sister chromatid cohesion.

  15. Effect of new adhesion promoter and mechanical interlocking on bonding strength in metal-polymer composites

    NASA Astrophysics Data System (ADS)

    Schuberth, A.; Göring, M.; Lindner, T.; Töberling, G.; Puschmann, M.; Riedel, F.; Scharf, I.; Schreiter, K.; Spange, S.; Lampke, T.

    2016-03-01

    There are various opportunities to improve the adhesion between polymer and metal in metal-plastic composites. The addition of a bonding agent which reacts with both joining components at the interfaces of the composite can enhance the bonding strength. An alternative method for the adjustment of interfaces in metal-plastic composites is the specific surface structuring of the joining partners in order to exploit the mechanical interlock effect. In this study the potential of using an adhesion promoter based on twin polymerization for metal-plastic composites in combination with different methods of mechanical surface treatment is evaluated by using the tensile shear test. It is shown that the new adhesion promoter has a major effect when applied on smooth metal surfaces. A combination of both mechanical and chemical surface treatment of the metal part is mostly just as effective as the application of only one of these surface treatment methods.

  16. Distally based dorsalis pedis island flap for a distal lateral electric burn of the big toe.

    PubMed

    Governa, M; Barisoni, D

    1996-12-01

    Reconstruction of the small defects in the distal portion of the foot has always represented a difficult problem. A case of a young man with a deep electric burn of the distal lateral side of the big toe successfully treated with a distally based dorsalis pedis island flap based on the first dorsal metatarsal artery (FDMA) is presented. The donor site area of the dorsum of the foot was grafted, and deambulation was reassumed 3 weeks later. Advantages; limits and anatomical consideration regarding the viability of the flap are also discussed.

  17. A biomechanical study of two different pedicle screw methods for fixation in osteoporotic and nonosteoporotic vertebrae.

    PubMed

    Higashino, Kosaku; Kim, Jin Hwan; Horton, William C; Hutton, William C

    2012-01-01

    In reconstruction of the osteoporotic spine, patients often show poor outcome because of pedicle screw failure. This study used osteoporotic and nonosteoporotic vertebrae to determine the difference in fixation strength between pedicle screws inserted straight forward and pedicle screws inserted in an upward trajectory toward the superior end plate (i.e., end-plate screws). There is some evidence to suggest that end-plate screws have a strength advantage. The particular focus was on osteoporotic vertebrae. Thirty-three vertebrae (T10-L2) were harvested. The bone mineral density (BMD) was measured: 15 vertebrae were greater than 0.8 g/cm(2) and designated as nonosteoporotic (average BMD 1.146 ± 0.186 g/cm(2)) and 18 vertebrae were designated as osteoporotic (average BMD 0.643 ± 0.088 g/cm(2)). On one pedicle the screw was inserted straight forward and on the other pedicle the screw was inserted as an end-plate screw. The torque of insertion was measured (Proto 6106 torque screwdriver). Using an MTS Mini Bionix, two types of mechanical testing were carried out on each pedicle: (a) cephalocaudad toggling was first carried out to simulate some physiological type loading: 500 cycles at 0.3 Hz, at ±50 N; and (b) then each pedicle screw was pulled out at a displacement rate of 12.5 cm/min.There was no difference in pullout force between the pedicle screws inserted straight forward and the pedicle screws inserted as end-plate screws. This result applies whether the vertebrae were osteoporotic or nonosteoporotic. For both the straight-forward screws and the end-plate screws, a statistically significant correlation was observed between torque of insertion and pullout force. The results of this experiment indicate that pedicle screws inserted as end-plate screws do not provide a strength advantage over pedicle screws inserted straight forward, whether the vertebrae are osteoporotic or not.

  18. Interfragmentary compression forces of scaphoid screws in a sawbone cylinder model.

    PubMed

    Hausmann, J T; Mayr, W; Unger, E; Benesch, T; Vécsei, V; Gäbler, C

    2007-07-01

    Various screws have been developed to stabilise fractures of the scaphoid. Commonly used are the Herbert, the HBS, the 3-mm AO and the Acutrak screws. Not long ago a new screw, the Twin Fix, was introduced. This is cannulated and similar in shape and appearance to the classical Herbert screw. In our test series we compared the maximum achievable compression forces of the Twin Fix screw with that of three other screws (AO, HBS and Acutrak screws). To avoid the variations of density, stiffness and rigidity in natural bone, a polyurethane sawbone-based test setup was used. The test series included 10 screws of each type. The compression force was measured using a special strain gauge. The mean compression force was significantly higher for the Twin Fix screw (8+/-1N) and the Acutrak screw (7.6+/-0.4/0.6N) in relation to the AO screw (6.8+/-1.0/1.4N) and HBS screw (2+/-1N). We found the Twin Fix and Acutrak screws to be promising in the treatment of scaphoid fractures.

  19. A New Distal Radioulnar Joint Prosthesis

    PubMed Central

    Schuurman, Arnold H.

    2013-01-01

    Pain and instability of the distal radioulnar joint (DRUJ) are common sequelae following a fracture of the distal radius. Many soft tissue procedures have been described, not all of which are successful. Ulnar head replacement prostheses are available but do not always provide stability. We designed a two-part, easy to implant, distal radioulnar prosthesis and implanted it in 19 patients. The first prototype was inserted in 2002 and is still in place. During the study, the design was changed twice, resulting in three groups with four patients in group A, five in group B, and ten in group C. Unfortunately all five prostheses in group B had to be removed because of loosening, while only two prostheses in group C had to be removed, for nonprosthetic reasons. For the 12 patients who retained their prosthesis, forearm function increased while grip strength increased significantly. Pain scores decreased and the Disabilities of the Arm, Shoulder, and Hand (DASH) score improved but remained high. We conclude that the prosthesis offers a new treatment option for ulnar instability following distal ulnar resection. PMID:24436843

  20. Anaesthetic management in thoracoscopic distal tracheal resection.

    PubMed

    Acosta Martínez, J; Beato López, J; Domínguez Blanco, A; López Romero, J L; López Villalobos, J L

    2017-03-01

    Surgical resection of tracheal tumours, especially distal tracheal tumours, is a challenge for the anaesthesiologists involved, mainly due to difficulties in ensuring adequate control of the airway and ventilation. We report the case of a patient undergoing tracheal resection and anastomosis by VATS, emphasizing the anaesthetic management.

  1. Interlocking of chelae is a key factor for dominance hierarchy formation in crayfish.

    PubMed

    Ueno, Ryusuke; Nagayama, Toshiki

    2012-08-15

    We characterized the role of chelae during agonistic encounters of the crayfish Procambarus clarkii. Physical asymmetries in body length, body mass and chelae size were directly related to dominance hierarchy formation. More than 80% of winning crayfish had longer body and chelae lengths, and winners were usually heavier in body mass, even if their differences were less than 3% compared with losing opponents. In mismatched pairings, large crayfish with short chelae were beaten by small crayfish with large chelae. Three physical elements of body length, body mass and chelae length equally affected the outcome of agonistic bouts. Chelae restriction, in which chelae were tightly closed using rubber bands, affected the outcome of agonistic bouts between large and small crayfish. Before chelae restriction, large crayfish won in all pairings. Following chelae restriction for at least 30 days from the first encounters, the winning rate of large crayfish that were previous winners decreased significantly in the second encounters against the same opponents that were previous losers. The handicap of chelae restriction significantly prolonged the time to formation of the winner-loser relationship. Individual fights escalated during agonistic bouts between large crayfish with one chela restricted and small crayfish with intact chelae, whereas the number of fights increased but the duration of individual fights did not increase in large crayfish with both chelae restricted. Furthermore, when the chelae of both large and small crayfish were disabled, the dominance order was frequently not formed during 30 min of agonistic bouts. Preventing chelae from interlocking prevented escalation of agonistic bouts. We show that interlocking of chelae acted as a key factor for the formation of dominance hierarchy.

  2. Reverse distal femoral locking compression plate a salvage option in nonunion of proximal femoral fractures

    PubMed Central

    Dumbre Patil, Sampat S; Karkamkar, Sachin S; Patil, Vaishali S Dumbre; Patil, Shailesh S; Ranaware, Abhijeet S

    2016-01-01

    Background: When primary fixation of proximal femoral fractures with implants fails, revision osteosynthesis may be challenging. Tracts of previous implants and remaining insufficient bone stock in the proximal femur pose unique problems for the treatment. Intramedullary implants like proximal femoral nail (PFN) or surface implants like Dynamic Condylar Screw (DCS) are few of the described implants for revision surgery. There is no evidence in the literature to choose one implant over the other. We used the reverse distal femur locking compression plate (LCP) of the contralateral side in such cases undergoing revision surgery. This implant has multiple options of fixation in proximal femur and its curvature along the length matches the anterior bow of the femur. We aimed to evaluate the efficacy of this implant in salvage situations. Materials and Methods: Twenty patients of failed primary proximal femoral fractures who underwent revision surgery with reverse distal femoral locking plate from February 2009 to November 2012 were included in this retrospective study. There were 18 subtrochanteric fractures and two ipsilateral femoral neck and shaft fractures, which exhibited delayed union or nonunion. The study included 14 males and six females. The mean patient age was 43.6 years (range 22–65 years) and mean followup period was 52.1 months (range 27–72 months). Delayed union was considered when clinical and radiological signs of union failed to progress at the end of four months from initial surgery. Results: All fractures exhibited union without any complications. Union was assessed clinically and radiologically. One case of ipsilateral femoral neck and shaft fracture required bone grafting at the second stage for delayed union of the femoral shaft fracture. Conclusions: Reverse distal femoral LCP of the contralateral side can be used as a salvage option for failed fixation of proximal femoral fractures exhibiting nonunion. PMID:27512218

  3. Numerical and experimental study of an Archimedean Screw Generator

    NASA Astrophysics Data System (ADS)

    Dellinger, G.; Garambois, P.-A.; Dufresne, M.; Terfous, A.; Vazquez, J.; Ghenaim, A.

    2016-11-01

    Finding new, safe and renewable energy is becoming more and more of a priority with global warming. One solution that is gaining popularity is the Archimedean Screw Generator (ASG). This kind of hydroelectric plant allows transforming potential energy of a fluid into mechanical energy and is convenient for low-head hydraulic sites. As it is a new and growing technology, there are few references dealing with their design and performance optimization. The present contribution proposes to investigate experimentally and numerically the ASG performances. The experimental study is performed for various flow conditions and a laboratory scale screw device installed at the fluid mechanics laboratory of the INSA of Strasbourg. The first results show that the screw efficiencies are higher than 80% for various hydraulic conditions. In order to study the structure of 3D turbulent flows and energy losses in a screw, the 3D Navier Stokes equations are solved with the k-w SST turbulence model. The exact geometry of the laboratory-scale screw was used in these simulations. Interestingly, the modeled values of efficiency are in fairly good agreement with experimental results while any friction coefficient is involved.

  4. Numerical simulation of a twin screw expander for performance prediction

    NASA Astrophysics Data System (ADS)

    Papes, Iva; Degroote, Joris; Vierendeels, Jan

    2015-08-01

    With the increasing use of twin screw expanders in waste heat recovery applications, the performance prediction of these machines plays an important role. This paper presents a mathematical model for calculating the performance of a twin screw expander. From the mass and energy conservation laws, differential equations are derived which are then solved together with the appropriate Equation of State in the instantaneous control volumes. Different flow processes that occur inside the screw expander such as filling (accompanied by a substantial pressure loss) and leakage flows through the clearances are accounted for in the model. The mathematical model employs all geometrical parameters such as chamber volume, suction and leakage areas. With R245fa as working fluid, the Aungier Redlich-Kwong Equation of State has been used in order to include real gas effects. To calculate the mass flow rates through the leakage paths formed inside the screw expander, flow coefficients are considered as constant and they are derived from 3D Computational Fluid Dynamic calculations at given working conditions and applied to all other working conditions. The outcome of the mathematical model is the P-V indicator diagram which is compared to CFD results of the same twin screw expander. Since CFD calculations require significant computational time, developed mathematical model can be used for the faster performance prediction.

  5. Outcome of anatomic locking plate in extraarticular distal humeral shaft fractures

    PubMed Central

    Jain, Deepak; Goyal, Gurpreet S; Garg, Rajnish; Mahindra, Pankaj; Yamin, Mohammad; Selhi, Harpal S

    2017-01-01

    Background: Extraarticular fractures of distal humerus are challenging injuries to treat because of complex anatomy and fracture patterns. Functional bracing may not provide adequate stability in these injuries and operative treatment with intramedullary nails or conventional plates also has the limitation of inadequate fixation in the short distal fragment. The 3.5 mm precontoured single column locking plate (extraarticular distal humerus plate [EADHP]) has been introduced to overcome this problem. We evaluated the clinical and functional outcomes of treating these fractures with the EADHP. Materials and Methods: 26 patients with extraarticular fractures of distal humerus presenting within 3 weeks of injury between January 2012 and June 2015, were included in this prospective study. Open IIIB and IIIC fractures, nonunions, or those with a history of previous infection in the arm were excluded. Operative fixation was done using the EADHP in all the cases. The time for union, range of motion at shoulder and elbow and secondary procedures were recorded in followup. The shoulder and elbow function was assessed using the University of California Los Angeles (UCLA) shoulder scale and Mayo Elbow Performance Score (MEPS) respectively. Results: There were 21 males and 5 females with mean age of 37.3 years (range 18–72 years). Twenty two (84.6%) cases had complex fracture patterns (AO/OTA Type 12-B and C). The mean time to fracture union was 22.4 weeks (range 16–28 weeks). The mean followup time was 11.6 months, (range 4-24 months). Four patients (15.4%) had failure of cortical screws in the proximal fracture fragment, of which two required revision fixation with bone grafting. Another nonunion was seen following a surgical site infection, which healed after wound lavage and bone grafting. The MEPS (average: 96.1; range 80–100) was excellent in 81% cases (n = 21) and good in 19% cases (n = 5). UCLA score (average: 33.5; range 25-35) was good/excellent in 88.5% cases

  6. A locked hip screw-intramedullary nail (cephalomedullary nail) for the treatment of fractures of the proximal part of the femur combined with fractures of the femoral shaft.

    PubMed

    Alho, A; Ekeland, A; Grøgaard, B; Dokke, J R

    1996-01-01

    Twenty-seven patients with complex femoral fractures (combined shaft and proximal femoral fractures) were treated with a modified Grosse-Kempf slotted locking nail (cephalomedullary nail), wherein two screws were inserted in the hip. Four types of complex, multifocal femoral fractures were represented in the series. Eleven of the femoral shaft fractures were secondary to a previous, internally fixed, not yet united hip fracture (type I). Ten comminuted peritrochanteric fractures occurred in normal bone (type II). Three similar fractures were pathologic because of metastasis. Two patients had an ipsilateral fracture of the femoral shaft and the trochanteric area (type III), and one of the shaft and the femoral neck (type IV). Locking was made static in 24 cases. Additional cerclage wiring was used in three type II fractures. Five complications were as follows: one cutting out of a screw in the femoral head, two fractures of the nail, one deep venous thrombosis, and one wound hematoma. Reoperations were two salvage operations using a new nail and one evacuation of hematoma. One patient with multiple injuries and four elderly patients died within 2 months. Eighteen patients with fractures in normal bone were followed for a median of 20 (6 to 37) months. All fractures united. Two nails were removed. The end result was excellent in ten patients, good in seven, and fair in one (2-cm shortening and 20-degree external rotation). We conclude that a locked intramedullary construct with locking screws in femoral neck and distal femur controls a complex fracture situation well.

  7. Posterior fusion only for thoracic adolescent idiopathic scoliosis of more than 80°: pedicle screws versus hybrid instrumentation

    PubMed Central

    Bakaloudis, Georgios; Lolli, Francesco; Vommaro, Francesco; Martikos, Konstantinos; Parisini, Patrizio

    2008-01-01

    The treatment of thoracic adolescent idiopathic scoliosis (AIS) of more than 80° traditionally consisted of a combined procedure, an anterior release performed through an open thoracotomy followed by a posterior fusion. Recently, some studies have reassessed the role of posterior fusion only as treatment for severe thoracic AIS; the correction rate of the thoracic curves was comparable to most series of combined anterior and posterior surgery, with shorter surgery time and without the negative effect on pulmonary function of anterior transthoracic exposure. Compared with other studies published so far on the use of posterior fusion alone for severe thoracic AIS, the present study examines a larger group of patients (52 cases) reviewed at a longer follow-up (average 6.7 years, range 4.5–8.5 years). The aim of the study was to evaluate the clinical and radiographic outcome of surgical treatment for severe thoracic (>80°) AIS treated with posterior spinal fusion alone, and compare comprehensively the results of posterior fusion with a hybrid construct (proximal hooks and distal pedicle screws) versus a pedicle screw instrumentation. All patients (n = 52) with main thoracic AIS curves greater than 80° (Lenke type 1, 2, 3, and 4), surgically treated between 1996 and 2000 at one institution, by posterior spinal fusion either with hybrid instrumentation (PSF–H group; n = 27 patients), or with pedicle screw-only construct (PSF–S group; n = 25 patients) were reviewed. There were no differences between the two groups in terms of age, Risser’s sign, Cobb preoperative main thoracic (MT) curve magnitude (PSF–H: 92° vs. PSF–S: 88°), or flexibility on bending films (PSF–H: 27% vs. PSF–S: 25%). Statistical analysis was performed using the t test (paired and unpaired), Wilcoxon test for non-parametric paired analysis, and the Mann–Whitney test for non-parametric unpaired analysis. At the last follow-up, the PSF–S group, when compared to the PSF

  8. The use of pedicle-screw internal fixation for the operative treatment of spinal disorders.

    PubMed

    Gaines, R W

    2000-10-01

    Pedicle screws have dramatically improved the outcomes of spinal reconstruction requiring spinal fusion. Short-segment surgical treatments based on the use of pedicle screws for the treatment of neoplastic, developmental, congenital, traumatic, and degenerative conditions have been proved to be practical, safe, and effective. The Funnel Technique provides a straightforward, direct, and inexpensive way to very safely apply pedicle screws in the cervical, thoracic, or lumbar spine. Carefully applied pedicle-screw fixation does not produce severe or frequent complications. Pedicle-screw fixation can be effectively and safely used wherever a vertebral pedicle can accommodate a pedicle screw--that is, in the cervical, thoracic, or lumbar spine. Training in pedicle-screw application should be standard in orthopaedic training programs since pedicle-screw fixation represents the so-called gold standard of spinal internal fixation.

  9. Effects of lag screw design and lubrication on sliding in trochanteric nails.

    PubMed

    Kummer, Frederick J

    2010-01-01

    This study compared the sliding characteristics of three lag screw designs used with trochanteric nails and determined the effects of lubrication on sliding. They were tested by an established method to measure initiation and ease of lag screw sliding. These tests were then repeated with calf serum lubrication. There were significant differences (p < 0.05) between the loads required to initiate lag screw sliding that appeared to be related to design. Screw sliding was similar for all three designs; however, the presence of lag screw locking slots affected sliding in that region. Lubrication did not affect either parameter. Lag screw design aspects, such as diameter and, particularly, surface finish, affect sliding. Due to the small contact area between the lag screw and nail creating high interface stresses, lubrication had no effect on lag screw sliding.

  10. Optically driven Archimedes micro-screws for micropump application.

    PubMed

    Lin, Chih-Lang; Vitrant, Guy; Bouriau, Michel; Casalegno, Roger; Baldeck, Patrice L

    2011-04-25

    Archimedes micro-screws have been fabricated by three-dimensional two-photon polymerization using a Nd:YAG Q-switched microchip laser at 532nm. Due to their small sizes they can be easily manipulated, and made to rotate using low power optical tweezers. Rotation rates up to 40 Hz are obtained with a laser power of 200 mW, i.e. 0.2 Hz/mW. A photo-driven micropump action in a microfluidic channel is demonstrated with a non-optimized flow rate of 6 pL/min. The optofluidic properties of such type of Archimedes micro-screws are quantitatively described by the conservation of momentum that occurs when the laser photons are reflected on the helical micro-screw surface.

  11. Study on the performance prediction of screw vacuum pump

    NASA Astrophysics Data System (ADS)

    Ohbayashi, T.; Sawada, T.; Hamaguchi, M.; Miyamura, H.

    2001-01-01

    Pumping characteristics of the screw vacuum pump were investigated. The aim of this study was to establish a method of the performance prediction and a way to design the pump that satisfies specific requirements. The performance was analysed by the balance among geometrical pumping speed, net throughput and leaks. The leaks flow through clearances between a screw rotor and a stator, and clearances between two meshing rotors. These leaks were estimated with the results based on the linearised BGK model and the flows through ideal labyrinthes. Experiments were carried out by rotors of 120 mm diameter, and pumping speed and ultimate pressure were measured. The comparison between the measurements and the predicted values shows that the present method predicts the performance of the screw pump with a sufficient accuracy for practical applications.

  12. Mechanical Properties of Nanotextured Titanium Orthopedic Screws for Clinical Applications.

    PubMed

    Descamps, Stephane; Awitor, Komla O; Raspal, Vincent; Johnson, Matthew B; Bokalawela, Roshan S P; Larson, Preston R; Doiron, Curtis F

    2013-06-01

    In this work, we modified the topography of commercial titanium orthopedic screws using electrochemical anodization in a 0.4 wt% hydrofluoric acid solution to produce titanium dioxide nanotube layers. The morphology of the nanotube layers were characterized using scanning electron microscopy. The mechanical properties of the nanotube layers were investigated by screwing and unscrewing an anodized screw into several different types of human bone while the torsional force applied to the screwdriver was measured using a torque screwdriver. The range of torsional force applied to the screwdriver was between 5 and [Formula: see text]. Independent assessment of the mechanical properties of the same surfaces was performed on simple anodized titanium foils using a triboindenter. Results showed that the fabricated nanotube layers can resist mechanical stresses close to those found in clinical situations.

  13. Efficiency study of oil cooling of a screw compressor

    SciTech Connect

    Tree, D.R.; McKellar, M.G.

    1989-04-01

    One of the major goals of all compressor manufacturers is to build as efficient a compressor as possible. Over the last several years improvements to the design of screw compressors has made them efficiently competitive with other types of compressors, especially at large loads. The primary purpose of this research is to investigate four different methods of cooling a 250 horsepower compressor and determine their effects on the efficiency of the compressor. Two conventional methods, liquid injection and thermosyphon cooling, and two new methods, V-PLUS and Fresco oil injection, are investigated. The screw compressor used in the tests was a VRS-500 screw compressor made by the Vilter Manufacturing Corporation. 6 figs.

  14. Mild coal gasification screw pyrolyzer development and design

    SciTech Connect

    Camp, D.W.

    1990-08-01

    Our objective is to produce information and design recommendations needed for the development of an efficient continuous process for the mild gasification of caking bituminous coals. We have focused on the development of an externally heated pyrolyzer in which the sticky, reacting coal is conveyed by one or more screws. We have taken a multifaceted approach to forwarding the development of the externally-heated screw pyrolyzer. Small scale process experiments on a 38-mm single screw pyrolyzer have been a major part of our effort. Engineering analyses aimed at producing design and scaleup equations have also been important. Process design recommendations follow from these. We critically review our experimental data and experience, and information from the literature and equipment manufactures for the purpose of making qualitative recommendations for improving practical pyrolyzer design and operation. Benchscale experiments are used to supply needed data and test some preliminary concepts. 6 refs., 4 figs., 1 tab.

  15. Retrograde Tibial Nailing: a minimally invasive and biomechanically superior alternative to angle-stable plate osteosynthesis in distal tibia fractures

    PubMed Central

    2014-01-01

    Background Currently, antegrade intramedullary nailing and minimally invasive plate osteosynthesis (MIPO) represent the main surgical alternatives in distal tibial fractures. However, neither choice is optimal for all bony and soft tissue injuries. The Retrograde Tibial Nail (RTN) is a small-caliber prototype implant, which is introduced through a 2-cm-long incision at the tip of the medial malleolus with stab incisions sufficient for interlocking. During this project, we investigated the feasibility of retrograde tibial nailing in a cadaver model and conducted biomechanical testing. Methods Anatomical implantations of the RTN were carried out in AO/OTA 43 A1-3 fracture types in three cadaveric lower limbs. Biomechanical testing was conducted in an AO/OTA 43 A3 fracture model for extra-axial compression, torsion, and destructive extra-axial compression. Sixteen composite tibiae were used to compare the RTN against an angle-stable plate osteosynthesis (Medial Distal Tibial Plate, Synthes®). Statistical analysis was performed by Student's t test. Results Retrograde intramedullary nailing is feasible in simple fracture types by closed manual reduction and percutaneous reduction forceps, while in highly comminuted fractures, the use of a large distractor can aid the reduction. Biomechanical testing shows a statistically superior stability (p < 0.001) of the RTN during non-destructive axial loading and torsion. Destructive extra-axial compression testing resulted in failure of all plate constructs, while all RTN specimens survived the maximal load of 1,200 N. Conclusions The prototype retrograde tibial nail meets the requirements of maximum soft tissue protection by a minimally invasive surgical approach with the ability of secure fracture fixation by multiple locking options. Retrograde tibial nailing with the RTN is a promising concept in the treatment of distal tibia fractures. PMID:24886667

  16. Quantitative comparison between the straight-forward and anatomical insertion technique for pedicle screw placement

    NASA Astrophysics Data System (ADS)

    Knez, Dejan; Mohar, Janez; Likar, Boštjan; Pernuš, Franjo; Vrtovec, Tomaž

    2016-03-01

    Spinal deformity correction with vertebral fixation is nowadays the preferred surgical treatment, where pedicle screws are inserted through pedicles into corresponding vertebral bodies and afterwards connected with rods. In clinical practice, the straight-forward and anatomical insertion technique are currently being used for pedicle screw placement surgery. However, it is difficult to quantitatively compare both techniques and determine which technique is more adequate for each planned pedicle screw before surgery (i.e. preoperatively). In this paper, we therefore describe a framework for quantitative comparison between the straight-forward and anatomical insertion technique for pedicle screw placement surgery by evaluating the screw fastening strength. Quantitative comparisons were performed on computed tomography images of 11 patients with 74 manually planned pedicle screws, who underwent the vertebral fixation procedure. The first quantitative comparison was performed between the straight-forward and anatomical pedicle screw insertion technique, which resulted in a relatively high agreement with mean absolute difference of 0.0mm in screw diameter, 2.9mm in screw length, 1.2mm in pedicle crossing point and 6.5° in screw inclinations. The second quantitative comparison was performed between the best resulting pedicle screw insertion technique and manually obtained pedicle screw plans, which again resulted in a relatively high agreement with mean absolute difference of 0.5mm in screw diameter, 4.7mm in screw length, 2.4mm in pedicle crossing point and 6.0° in screw inclinations. Both the straight-forward and anatomical insertion technique proved approximately equal in terms of the screw fastening strength.

  17. Screw-in forces during instrumentation by various file systems

    PubMed Central

    2016-01-01

    Objectives The purpose of this study was to compare the maximum screw-in forces generated during the movement of various Nickel-Titanium (NiTi) file systems. Materials and Methods Forty simulated canals in resin blocks were randomly divided into 4 groups for the following instruments: Mtwo size 25/0.07 (MTW, VDW GmbH), Reciproc R25 (RPR, VDW GmbH), ProTaper Universal F2 (PTU, Dentsply Maillefer), and ProTaper Next X2 (PTN, Dentsply Maillefer, n = 10). All the artificial canals were prepared to obtain a standardized lumen by using ProTaper Universal F1. Screw-in forces were measured using a custom-made experimental device (AEndoS-k, DMJ system) during instrumentation with each NiTi file system using the designated movement. The rotation speed was set at 350 rpm with an automatic 4 mm pecking motion at a speed of 1 mm/sec. The pecking depth was increased by 1 mm for each pecking motion until the file reach the working length. Forces were recorded during file movement, and the maximum force was extracted from the data. Maximum screw-in forces were analyzed by one-way ANOVA and Tukey's post hoc comparison at a significance level of 95%. Results Reciproc and ProTaper Universal files generated the highest maximum screw-in forces among all the instruments while M-two and ProTaper Next showed the lowest (p < 0.05). Conclusions Geometrical differences rather than shaping motion and alloys may affect the screw-in force during canal instrumentation. To reduce screw-in forces, the use of NiTi files with smaller cross-sectional area for higher flexibility is recommended. PMID:27847752

  18. Comparison of effectiveness between cork-screw and peg-screw electrodes for transcranial motor evoked potential monitoring using the finite element method

    PubMed Central

    Tomio, Ryosuke; Akiyama, Takenori; Ohira, Takayuki; Yoshida, Kazunari

    2016-01-01

    Background: Intraoperative monitoring of motor evoked potentials by transcranial electric stimulation is popular in neurosurgery for monitoring motor function preservation. Some authors have reported that the peg-screw electrodes screwed into the skull can more effectively conduct current to the brain compared to subdermal cork-screw electrodes screwed into the skin. The aim of this study was to investigate the influence of electrode design on transcranial motor evoked potential monitoring. We estimated differences in effectiveness between the cork-screw electrode, peg-screw electrode, and cortical electrode to produce electric fields in the brain. Methods: We used the finite element method to visualize electric fields in the brain generated by transcranial electric stimulation using realistic three-dimensional head models developed from T1-weighted images. Surfaces from five layers of the head were separated as accurately as possible. We created the “cork-screws model,” “1 peg-screw model,” “peg-screws model,” and “cortical electrode model”. Results: Electric fields in the brain radially diffused from the brain surface at a maximum just below the electrodes in coronal sections. The coronal sections and surface views of the brain showed higher electric field distributions under the peg-screw compared to the cork-screw. An extremely high electric field was observed under cortical electrodes. Conclusion: Our main finding was that the intensity of electric fields in the brain are higher in the peg-screw model than the cork-screw model. PMID:27920938

  19. INDICATIONS FOR DISTAL RADIOULNAR ARTHROPLASTY: REPORT ON THREE CLINICAL CASES

    PubMed Central

    Santos, Cláudia; Pereira, Alexandre; Sousa, Marco; Trigeuiros, Miguel; Silva, César

    2015-01-01

    Distal radioulnar arthroplasty is an attractive solution for treating various pathological conditions of the distal radioulnar joint because it allows restoration of stability, load transmission and function. The main indications are: radioulnar impingement after partial or complete resection of the distal ulna; and degenerative, inflammatory or post-traumatic arthritis of the distal radioulnar joint. The authors present three clinical cases of distal radioulnar pathological conditions: two patients with post-traumatic sequelae and one case of distal radioulnar impingement after a Sauvé-Kapandji operation. The three cases were treated surgically with a metallic prosthesis to replace the distal ulna (First Choice - Ascension®). The first two were treated with a resurfacing prosthesis and the last one with a modular prosthesis. All of the patients had achieved pain relief and increased movement of the distal radioulnar joint after one year of postoperative follow-up. PMID:27047827

  20. Virtual estimates of fastening strength for pedicle screw implantation procedures

    NASA Astrophysics Data System (ADS)

    Linte, Cristian A.; Camp, Jon J.; Augustine, Kurt E.; Huddleston, Paul M.; Robb, Richard A.; Holmes, David R.

    2014-03-01

    Traditional 2D images provide limited use for accurate planning of spine interventions, mainly due to the complex 3D anatomy of the spine and close proximity of nerve bundles and vascular structures that must be avoided during the procedure. Our previously developed clinician-friendly platform for spine surgery planning takes advantage of 3D pre-operative images, to enable oblique reformatting and 3D rendering of individual or multiple vertebrae, interactive templating, and placement of virtual pedicle implants. Here we extend the capabilities of the planning platform and demonstrate how the virtual templating approach not only assists with the selection of the optimal implant size and trajectory, but can also be augmented to provide surrogate estimates of the fastening strength of the implanted pedicle screws based on implant dimension and bone mineral density of the displaced bone substrate. According to the failure theories, each screw withstands a maximum holding power that is directly proportional to the screw diameter (D), the length of the in-bone segm,ent of the screw (L), and the density (i.e., bone mineral density) of the pedicle body. In this application, voxel intensity is used as a surrogate measure of the bone mineral density (BMD) of the pedicle body segment displaced by the screw. We conducted an initial assessment of the developed platform using retrospective pre- and post-operative clinical 3D CT data from four patients who underwent spine surgery, consisting of a total of 26 pedicle screws implanted in the lumbar spine. The Fastening Strength of the planned implants was directly assessed by estimating the intensity - area product across the pedicle volume displaced by the virtually implanted screw. For post-operative assessment, each vertebra was registered to its homologous counterpart in the pre-operative image using an intensity-based rigid registration followed by manual adjustment. Following registration, the Fastening Strength was computed

  1. 46 CFR 154.524 - Piping joints: Welded and screwed couplings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Piping joints: Welded and screwed couplings. 154.524... Equipment Cargo and Process Piping Systems § 154.524 Piping joints: Welded and screwed couplings. Pipe... warmer. (d) Screwed couplings are allowed for instrumentation and control piping that meets §...

  2. 46 CFR 154.524 - Piping joints: Welded and screwed couplings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Piping joints: Welded and screwed couplings. 154.524... Equipment Cargo and Process Piping Systems § 154.524 Piping joints: Welded and screwed couplings. Pipe... warmer. (d) Screwed couplings are allowed for instrumentation and control piping that meets §...

  3. 46 CFR 154.524 - Piping joints: Welded and screwed couplings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Piping joints: Welded and screwed couplings. 154.524... Equipment Cargo and Process Piping Systems § 154.524 Piping joints: Welded and screwed couplings. Pipe... warmer. (d) Screwed couplings are allowed for instrumentation and control piping that meets §...

  4. 46 CFR 154.524 - Piping joints: Welded and screwed couplings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Piping joints: Welded and screwed couplings. 154.524... Equipment Cargo and Process Piping Systems § 154.524 Piping joints: Welded and screwed couplings. Pipe... warmer. (d) Screwed couplings are allowed for instrumentation and control piping that meets §...

  5. 46 CFR 154.524 - Piping joints: Welded and screwed couplings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Piping joints: Welded and screwed couplings. 154.524... Equipment Cargo and Process Piping Systems § 154.524 Piping joints: Welded and screwed couplings. Pipe... warmer. (d) Screwed couplings are allowed for instrumentation and control piping that meets §...

  6. Fracture resistance of abutment screws made of titanium, polyetheretherketone, and carbon fiber-reinforced polyetheretherketone.

    PubMed

    Neumann, Eduardo Aloisio Fleck; Villar, Cristina Cunha; França, Fabiana Mantovani Gomes

    2014-01-01

    Fractured abutment screws may be replaced; however, sometimes, the screw cannot be removed and the entire implant must be surgically removed and replaced. The aim of this study was to compare the fracture resistance of abutment retention screws made of titanium, polyetheretherketone (PEEK) and 30% carbon fiber-reinforced PEEK, using an external hexagonal implant/UCLA-type abutment interface assembly. UCLA-type abutments were fixed to implants using titanium screws (Group 1), polyetheretherketone (PEEK) screws (Group 2), and 30% carbon fiber-reinforced PEEK screws (Group 3). The assemblies were placed on a stainless steel holding apparatus to allow for loading at 45o off-axis, in a universal testing machine. A 200 N load (static load) was applied at the central point of the abutment extremity, at a crosshead speed of 5 mm/minute, until failure. Data was analyzed by ANOVA and Tukey's range test. The titanium screws had higher fracture resistance, compared with PEEK and 30% carbon fiber-reinforced PEEK screws (p < 0.05). In contrast, no statistically significant difference was observed between the fracture resistance of the PEEK and the 30% carbon fiber-reinforced PEEK screws (p> 0.05). Finally, visual analysis of the fractions revealed that 100% of them occurred at the neck of the abutment screw, suggesting that this is the weakest point of this unit. PEEK abutment screws have lower fracture resistance, in comparison with titanium abutment screws.

  7. Breakdown of interlocking domains may contribute to formation of membranous globules and lens opacity in ephrin-A5(-/-) mice.

    PubMed

    Biswas, Sondip; Son, Alexander; Yu, Qili; Zhou, Renping; Lo, Woo-Kuen

    2016-04-01

    Ephrin-A5, a ligand of the Eph family of receptor tyrosine kinases, plays a key role in lens fiber cell packing and cell-cell adhesion, with approximately 87% of ephrin-A5(-/-) mice develop nuclear cataracts. Here, we investigated the extensive formation of light-scattering globules associated with breakdown of interlocking protrusions during lens opacification in ephrin-A5(-/-) mice. Lenses from wild-type (WT) and ephrin-A5(-/-) mice between 2 and 21 weeks old were studied with light and electron microscopy, immunofluorescence labeling, freeze-fracture TEM and filipin cytochemistry for membrane cholesterol detection. Lens opacities with various densities were first observed in ephrin-A5(-/-) mice at around 60 days old. Dense cataracts in the mutant lenses were seen primarily in the nuclear region surrounded by transparent cortices from all eyes examined. We confirmed that a majority of nuclear cataracts were dislocated posteriorly and ruptured the thinner posterior lens capsule. SEM analysis indicated that numerous interlocking protrusions and wavy ridge-and-valley membrane surfaces in deep cortical and nuclear fibers did not cause lens opacity in both transparent ephrin-A5(-/-) and WT mice. In contrast, abundant isolated membranous globules of approximately 1000 nm in size were distributed randomly along the intact fiber cells during early stage of all ephrin-A5(-/-) cataracts examined. A further examination using both SEM and TEM revealed that isolated globules were generated from the disintegrated interlocking protrusions originally located along the corners of hexagonal fiber cells. Freeze-fracture TEM further revealed the association of square-array aquaporin junctions with both isolated globules and interlocking membrane domains. This study reports for the first time that disrupted interlocking protrusions are the source of numerous large membranous globules that contribute to light scattering and nuclear cataracts in the ephrin-A5(-/-) mice. Our results

  8. Real-Time Estimation of Ball-Screw Thermal Elongation Based upon Temperature Distribution of Ball-Screw

    NASA Astrophysics Data System (ADS)

    Kodera, Takehiko; Yokoyama, Kazuhiro; Miyaguchi, Kazuo; Nagai, Yutaka; Suzuki, Takamasa; Masuda, Masami; Yazawa, Takanori

    The optical telemeter system has been developed, which converts the temperature of rotating spindle to the digital data and carries the digital data from LED on the rotating side toward PD on the stationary side by the optical data transmission. Based upon the temperature distribution of hollow ball-screw obtained by the telemeter system, the thermal elongation of the ball-screw is estimated as the one-dimensional thermal elongation. Estimation accuracy, which is the difference between the estimated thermal elongation and the measured thermal elongation, is -3.1∼+3.2µ m for the thermal elongation of 50-60µ m over the length of 935.5mm of the ball-screw.

  9. HEREDITARY DISTAL FORELEG CURVATURE IN THE RABBIT

    PubMed Central

    Pearce, Louise

    1960-01-01

    An inwardly directed curvature of the distal segment of both forelegs of the rabbit has been described. The condition was detected at 2 to 3 weeks of age, developed rapidly, and reached its final and permanent stage at 2 to 3 months of age. Only the distal epiphysis of the ulna was primarily affected and this in the form of a massive chondrodystrophic lesion accompanied by a progressive curvature of the shaft. The curvature of the growing radius was a secondary effect due to the firm, immovable, anatomical connection of the ulna and radius. The positional changes of the wrist and paw were likewise effects secondary to the changed form of the ulna and radius. The bowing abnormality occurred only in certain families of pure bred Beveren, Belgian, French Silver, and Dutch rabbits and was found to be inherited. The mode of inheritance was on the basis of a single recessive unit factor (5). PMID:13733755

  10. Diagnostic and Therapeutic Advances: Distal Symmetric Polyneuropathy

    PubMed Central

    Callaghan, Brian C.; Price, Raymond S.; Feldman, Eva L.

    2016-01-01

    Importance Peripheral neuropathy is a highly prevalent and morbid condition affecting 2–7% of the population. Patients frequently suffer from pain and are at risk of falls, ulcerations, and amputations. We aimed to review recent diagnostic and therapeutic advances in peripheral neuropathy in distal symmetric polyneuropathy, the most common subtype of peripheral neuropathy. Observations and Advances Current evidence supports limited routine laboratory testing in patients with distal symmetric polyneuropathy. Patients without a known cause should have a complete blood count, comprehensive metabolic panel, B12, serum protein electrophoresis with immunofixation, fasting glucose, and a glucose tolerance test. The presence of atypical features such as asymmetry, non-length-dependence, motor predominance, acute or subacute onset, and/or prominent autonomic involvement should prompt a consultation with a neurologist or neuromuscular specialist. Electrodiagnostic tests and magnetic resonance imaging of the neuroaxis are the main drivers of the cost of the diagnostic evaluation, but evidence supporting their use is lacking. Strong evidence supports the use of tricyclic antidepressants, serotonin and norepinephrine reuptake inhibitors, and voltage-gated calcium channel ligands in the treatment of neuropathic pain. More intensive glucose control substantially reduces the incidence of distal symmetric polyneuropathy in patients with type 1 diabetes, but does not in type 2 diabetes. Conclusions and Relevance The opportunity exists to improve guideline concordant testing in distal symmetric polyneuropathy patients. Moreover, the role of electrodiagnostic tests needs to be further defined, and interventions to reduce magnetic resonance imaging use in this population are needed. Even though several efficacious medications exist for neuropathic pain treatment, pain is still under-recognized and undertreated. New disease modifying medications are needed to prevent and treat

  11. [Laparoscopic distal resection of the pancreas].

    PubMed

    Gürlich, R; Sixta, B; Oliverius, M; Kment, M; Rusina, R; Spicák, J; Sváb, J

    2005-09-01

    During the last two years, reports on laparoscopic procedures of the pancreas have been on increase. Laparoscopic resection of the pancreatic cauda is indicated, primarily, for benign cystic lesions of the cauda of the pancreas and for neuroendocrine tumors of the pancreas (mainly insulinomas). We have not recorded any report on the above procedure in the Czech literature. Therefore, in our case review, we have described laparoscopic distal resection of the pancreas with splenectomy for a pseudopapillary tumor of the pancreas.

  12. Distal renal tubular acidosis with hereditary spherocytosis.

    PubMed

    Sinha, Rajiv; Agarwal, Indira; Bawazir, Waleed M; Bruce, Lesley J

    2013-07-01

    Hereditary spherocytosis (HS) and distal renal tubular acidosis (dRTA), although distinct entities, share the same protein i.e. the anion exchanger1 (AE1) protein. Despite this, their coexistence has been rarely reported. We hereby describe the largest family to date with co-existence of dRTA and HS and discuss the molecular basis for the co-inheritance of these conditions.

  13. Distal biceps tendon injuries: diagnosis and management.

    PubMed

    Ramsey, M L

    1999-01-01

    Rupture of the distal biceps tendon occurs most commonly in the dominant extremity of men between 40 and 60 years of age when an unexpected extension force is applied to the flexed arm. Although previously thought to be an uncommon injury, distal biceps tendon ruptures are being reported with increasing frequency. The rupture typically occurs at the tendon insertion into the radial tuberosity in an area of preexisting tendon degeneration. The diagnosis is made on the basis of a history of a painful, tearing sensation in the antecubital region. Physical examination demonstrates a palpable and visible deformity of the distal biceps muscle belly with weakness in flexion and supination. The ability to palpate the tendon in the antecubital fossa may indicate partial tearing of the biceps tendon. Plain radiographs may show hypertrophic bone formation at the radial tuberosity. Magnetic resonance imaging is generally not required to diagnose a complete rupture but may be useful in the case of a partial rupture. Early surgical reattachment to the radial tuberosity is recommended for optimal results. A modified two-incision technique is the most widely used method of repair, but anterior single-incision techniques may be equally effective provided the radial nerve is protected. The patient with a chronic rupture may benefit from surgical reattachment, but proximal retraction and scarring of the muscle belly can make tendon mobilization difficult, and inadequate length of the distal biceps tendon may necessitate tendon augmentation. Postoperative rehabilitation must emphasize protected return of motion for the first 8 weeks after repair. Formal strengthening may begin as early as 8 weeks, with a return to unrestricted activities, including lifting, by 5 months.

  14. Fractures of Distal Radius: An Overview

    PubMed Central

    Meena, Sanjay; Sharma, Pankaj; Sambharia, Abhishek Kumar; Dawar, Ashok

    2014-01-01

    Fractures of distal radius account for up to 20% of all fractures treated in emergency department. Initial assessment includes a history of mechanism of injury, associated injury and appropriate radiological evaluation. Treatment options include conservative management, internal fixation with pins, bridging and non-bridging external fixation, dorsal or volar plating with/without arthroscopy assistance. However, many questions regarding these fractures remain unanswered and good prospective randomized trials are needed. PMID:25657938

  15. Distal Embolic Protection for Renal Arterial Interventions

    SciTech Connect

    Dubel, Gregory J. Murphy, Timothy P.

    2008-01-15

    Distal or embolic protection has intuitive appeal for its potential to prevent embolization of materials generated during interventional procedures. Distal protection devices (DPDs) have been most widely used in the coronary and carotid vascular beds, where they have demonstrated the ability to trap embolic materials and, in some cases, to reduce complications. Given the frequency of chronic kidney disease in patients with renal artery stenosis undergoing stent placement, it is reasonable to propose that these devices may play an important role in limiting distal embolization in the renal vasculature. Careful review of the literature reveals that atheroembolization does occur during renal arterial interventions, although it often goes undetected. Early experience with DPDs in the renal arteries in patients with suitable anatomy suggests retrieval of embolic materials in approximately 71% of cases and renal functional improvement/stabilization in 98% of cases. The combination of platelet inhibition and a DPD may provide even greater benefit. Given the critical importance of renal functional preservation, it follows that everything that can be done to prevent atheroembolism should be undertaken including the use of DPDs when anatomically feasible. The data available at this time support a beneficial role for these devices.

  16. Triplane fracture of the distal radius.

    PubMed

    García-Mata, Serafín; Hidalgo-Ovejero, Angel

    2006-07-01

    A case of triplane fracture of the distal radius is reported in a 13-year-old boy. This exceptional fracture showed displacement, and was healed by closed reduction and 6 weeks of external immobilization. Eighteen months later, the patient showed complete physeal arrest of the distal radius, with radio-ulnar length discrepancy but without any repercussion on wrist mobility. The patient was declared asymptomatic 3 years after the injury. Prompt, physiological physeal arrest reduces the potential of growth deformity. These fractures must be treated conservatively by closed reduction (if displacement exists) and external immobilization, just like a normal one-plane fracture. We may suppose that final radio-ulnar discrepancy could lead to a painful and symptomatic ulno-carpal conflict in adult life. The following characteristics can be associated with this rare fracture: (1) occurrence close to the end of the growth period, as in other types of triplane fractures; (2) evolution towards partial or complete growth arrest of the physis, not requiring treatment and (3) stability of the fracture after closed reduction. In the present case, as in the other reported cases, it may also be added that orthopaedic treatment has been the rule, in contrast with triplane fractures occurring in the distal tibia, in which surgical treatment is indicated.

  17. Novel topical therapies for distal colitis.

    PubMed

    Lawrance, Ian Craig

    2010-10-06

    Distal colitis (DC) can be effectively treated with topical 5ASA agents. Suppositories target the rectum while enemas can reliably reach the splenic flexure. Used in combination with oral 5ASAs, the control of the inflammation is even more effective. Unfortunately, resistant DC does occur and can be extremely challenging to manage. In these patients, the use of steroids, immunosuppressants and the anti-tumor necrosis factor α agents are often required. These, however, can be associated with systemic side effects and are not always effective. The investigation of new topical therapeutic agents is thus required as they are rarely associated with significant blood drug levels and side effects are infrequent. Some of the agents that have been proposed for use in resistant distal colitis include butyrate, cyclosporine and nicotine enemas as well as tacrolimus suppositories and tacrolimus, ecabet sodium, arsenic, lidocaine, rebamipide and Ridogrel(®) enemas. Some of these agents have demonstrated impressive results but the majority of the agents have only been assessed in small open-labelled patient cohorts. Further work is thus required with the investigation of promising agents in the context of randomized double-blinded placebo controlled trials. This review aims to highlight those potentially effective therapies in the management of resistant distal colitis and to promote interest in furthering their investigation.

  18. Distal symmetrical polyneuropathy: definition for clinical research.

    PubMed

    England, J D; Gronseth, G S; Franklin, G; Miller, R G; Asbury, A K; Carter, G T; Cohen, J A; Fisher, M A; Howard, J F; Kinsella, L J; Latov, N; Lewis, R A; Low, P A; Sumner, A J

    2005-01-01

    The objective of this report was to develop a case definition of "distal symmetrical polyneuropathy" to standardize and facilitate clinical research and epidemiological studies. A formalized consensus process was employed to reach agreement after a systematic review and classification of evidence from the literature. The literature indicates that symptoms alone have relatively poor diagnostic accuracy in predicting the presence of polyneuropathy; signs are better predictors of polyneuropathy than symptoms; and single abnormalities on examination are less sensitive than multiple abnormalities in predicting the presence of polyneuropathy. The combination of neuropathic symptoms, signs, and electrodiagnostic findings provides the most accurate diagnosis of distal symmetrical polyneuropathy. A set of case definitions was rank ordered by likelihood of disease. The highest likelihood of polyneuropathy (useful for clinical trials) occurs with a combination of multiple symptoms, multiple signs, and abnormal electrodiagnostic studies. A modest likelihood of polyneuropathy (useful for field or epidemiological studies) occurs with a combination of multiple symptoms and multiple signs when the results of electrodiagnostic studies are not available. A lower likelihood of polyneuropathy occurs when electrodiagnostic studies and signs are discordant. For research purposes, the best approach for defining distal symmetrical polyneuropathy is a set of case definitions rank ordered by estimated likelihood of disease. The inclusion of this formalized case definition in clinical and epidemiological research studies will ensure greater consistency of case selection.

  19. A Focus on Triazolium as a Multipurpose Molecular Station for pH-Sensitive Interlocked Crown-Ether-Based Molecular Machines

    PubMed Central

    Coutrot, Frédéric

    2015-01-01

    The control of motion of one element with respect to others in an interlocked architecture allows for different co-conformational states of a molecule. This can result in variations of physical or chemical properties. The increase of knowledge in the field of molecular interactions led to the design, the synthesis, and the study of various systems of molecular machinery in a wide range of interlocked architectures. In this field, the discovery of new molecular stations for macrocycles is an attractive way to conceive original molecular machines. In the very recent past, the triazolium moiety proved to interact with crown ethers in interlocked molecules, so that it could be used as an ideal molecular station. It also served as a molecular barrier in order to lock interlaced structures or to compartmentalize interlocked molecular machines. This review describes the recently reported examples of pH-sensitive triazolium-containing molecular machines and their peculiar features. PMID:26491633

  20. Rotational Stability of Scaphoid Osteosyntheses: An In Vitro Comparison of Small Fragment Cannulated Screws to Novel Bone Screw Sets

    PubMed Central

    Erhart, Jochen; Unger, Ewald; Schefzig, Philip; Varga, Peter; Trulson, Inga; Gormasz, Anna; Trulson, Alexander; Reschl, Martin; Hagmann, Michael; Vecsei, Vilmos; Mayr, Winfried

    2016-01-01

    Background The current standard of care for operative repair of scaphoid fractures involves reduction and internal fixation with a single headless compression screw. However, a compression screw in isolation does not necessarily control rotational stability at a fracture or nonunion site. The single screw provides rotational control through friction and bone interdigitation from compression at the fracture site. We hypothesize that osteosyntheses with novel bone screw sets (BSS) equipped with anti-rotational elements provide improved rotational stability. Methods Stability of osteosynthesis under increasing cyclic torsional loading was investigated on osteotomized cadaveric scaphoids. Two novel prototype BSS, oblique type (BSS-obl.) and longitudinal type (BSS-long.) were compared to three conventional screws: Acutrak2®mini, HCS®3.0 and Twinfix®. Biomechanical tests were performed on scaphoids from single donors in paired comparison and analyzed by balanced incomplete random block design. Loading was increased by 50 mNm increments with 1,000 cycles per torque level and repeated until a rotational clearance of 10°. Primary outcome measure was the number of cycles to 10° clearance, secondary outcome measure was the maximum rotational clearance for each torque level. Findings BSS-obl. performed significantly better than Acutrak2®mini and HCS® (p = 0.015, p<0.0001). BSS-long. performed significantly better than HCS® (p = 0.010). No significant difference in performance between BSS-obl. and BSS-long. (p = 0.361), between BSS obl. and Twinfix® (p = 0.50) and BSS long. and Twinfix® (p = 0.667) was detected. Within the torque range up to 200 mNm, four of 21 (19%) BSS-long. and four of 21 (19%) BSS-obl. preparations showed early failure. The same loading led to early failure in four (29%) Twinfix®, seven (50%) Acutrak2®mini and 10 (71%) HCS® of 14 screw samples, respectively. Conclusions For both BSS and to a lesser extent for Twinfix® (as dual-component screw

  1. Benchtop comparison of a novel dynamic compression screw to a standard cortical screw: compression integrity and gap size over time during simulated resorption.

    PubMed

    Kinmon, Kyle; Garzon, Desiree; Tacktill, Jordan; Vassello, Wayne

    2013-06-01

    Literature reports the incidence of failed isolated foot and ankle fusions as up to 23%. A contributing factor is the natural bone resorption, which occurs resulting in loss of compression and gapping at the fusion site when standard static compression plates and screws are used. However, an innovative dynamic compression screw may provide lasting compression despite resorption. This benchtop study shows that the FxDEVICES spring-loaded dynamic POGO screw maintains more compression and more consistent compression rate during simulated resorption, as compared with a standard compression screw. The novel screw maintained much greater compression strength within the first millimeter of simulated resorption (13.57 vs 4.38 lb) and maintained greater compression strength at the test completion (1.14 vs 0 lb). The novel screw revealed a more consistent resorption rate over the duration of the simulation. Clinically, this may result in more stability and improved fusion rates.

  2. Geometrical evolution of interlocked rough slip surfaces: The role of normal stress

    NASA Astrophysics Data System (ADS)

    Badt, Nir; Hatzor, Yossef H.; Toussaint, Renaud; Sagy, Amir

    2016-06-01

    We study the evolution of slip surface topography using direct shear tests of perfectly mating surfaces. The tests are performed under imposed constant normal stress and constant slip rate conditions, to a sliding distance comparable to the roughness scale of the studied surfaces. Prismatic limestone blocks are fractured in tension using four-point bending and the generated surface topographies are measured using a laser profilometer. The initially rough fracture interfaces are tested in direct shear while ensuring a perfectly mating configuration at the beginning of each test. The predetermined sliding distance in all tests is 10 mm and the sliding velocity is 0.05 mm/s. A constant normal stress is maintained throughout the tests using closed loop servo control. The range of normal stresses applied is between 2 MPa and 15 MPa. After shearing, the surface topographies are re-scanned and the geometrical evolution is analyzed. We find that surface roughness increases with increasing normal stress: under normal stresses below 5 MPa the surfaces become smoother compared to the original geometry, whereas under normal stresses between 7.5 MPa and 15 MPa the surfaces clearly become rougher following shear. Statistical spectral analyses of the roughness profiles indicate that roughness increases with length-scale. Power spectral density values parallel to the slip orientation are fitted by power-law with typical power value of 2.6, corresponding to a Hurst exponent of 0.8, assuming self-affine roughness. This power value is consistent for the post-sheared surfaces and is obtained even when the original surface roughness does not follow initially a power-law form. The value of the scaling-law prefactor however increases with increasing normal stress. We find that the deformation associated with shearing initially rough interlocked surfaces extends beyond the immediate tested surface, further into the intact rock material. The intensity of the damage and its spatial

  3. Ground-state thermodynamics of bistable redox-active donor-acceptor mechanically interlocked molecules.

    PubMed

    Fahrenbach, Albert C; Bruns, Carson J; Cao, Dennis; Stoddart, J Fraser

    2012-09-18

    Fashioned through billions of years of evolution, biological molecular machines, such as ATP synthase, myosin, and kinesin, use the intricate relative motions of their components to drive some of life's most essential processes. Having control over the motions in molecules is imperative for life to function, and many chemists have designed, synthesized, and investigated artificial molecular systems that also express controllable motions within molecules. Using bistable mechanically interlocked molecules (MIMs), based on donor-acceptor recognition motifs, we have sought to imitate the sophisticated nanoscale machines present in living systems. In this Account, we analyze the thermodynamic characteristics of a series of redox-switchable [2]rotaxanes and [2]catenanes. Control and understanding of the relative intramolecular movements of components in MIMs have been vital in the development of a variety of applications of these compounds ranging from molecular electronic devices to drug delivery systems. These bistable donor-acceptor MIMs undergo redox-activated switching between two isomeric states. Under ambient conditions, the dominant translational isomer, the ground-state coconformation (GSCC), is in equilibrium with the less favored translational isomer, the metastable-state coconformation (MSCC). By manipulating the redox state of the recognition site associated with the GSCC, we can stimulate the relative movements of the components in these bistable MIMs. The thermodynamic parameters of model host-guest complexes provide a good starting point to rationalize the ratio of GSCC to MSCC at equilibrium. The bistable [2]rotaxanes show a strong correlation between the relative free energies of model complexes and the ground-state distribution constants (K(GS)). This relationship does not always hold for bistable [2]catenanes, most likely because of the additional steric and electronic constraints present when the two rings are mechanically interlocked with each other

  4. Metal-organic and supramolecular architectures based on mechanically interlocked molecules

    NASA Astrophysics Data System (ADS)

    Fernando, Isurika Rosini

    The focus of this work is on mechanically interlocked molecules (MIMs), which have unusual physicochemical and mechanical properties with potential applications in nano-scale/molecular devices and high strength materials. Rotaxanes, for example, consist of an axle-like molecule threaded through a wheel-like molecule, with bulky groups at the two ends of the axle preventing the wheel from dissociating. The position of the wheel along the axle can be switched in a controllable and reversible manner by applying external stimuli, a feature that might lead to the next generation of computers. Molecularly woven materials (MWMs), another example of molecules with mechanically interlocked features, are predicted to be unprecedentedly strong while being lightweight and flexible. With the ultimate goal of achieving control over the functioning of molecular devices in the solid state, a variety of pseudorotaxane building blocks were prepared and characterized, including a novel, rare blue-colored motif. The temperature-dependent assembly/disassembly of pseudorotaxanes was exploited for the construction of single-wavelength colorimetric temperature sensors over a 100 °C window. Pseudorotaxanes based on aromatic crown ether wheels and disubstituted 4,4'-bipyridinium axles were converted into rotaxanes upon binding to metal complexes (zinc, cadmium, mercury, copper, cobalt), and the formation of ordered crystalline arrays was studied in the solid state. The columnar organization of pseudorotaxanes by Hg2X6 2-- complexes (X = Cl, Br, I), leading to unprecedented dichroic (blue/red) rotaxane crystals, was demonstrated for the first time. From the crystal structures studied it became apparent that negatively charged metal complexes are needed for successful assembly with the positively charged pseudorotaxane units. To be able to use the more common, positively charged metal ions for rotaxane framework construction, neutral and negatively charged pseudorotaxanes were synthesized

  5. Role of rod diameter in comparison between only screws versus hooks and screws in posterior instrumentation of thoracic curve in idiopathic scoliosis.

    PubMed

    Lamartina, Claudio; Petruzzi, Maria; Macchia, Marcello; Stradiotti, Paola; Zerbi, Alberto

    2011-05-01

    Since the introduction of Cotrel-Dubousset instrumentation in 1984, the correction techniques in scoliosis surgery have changed from Harrington principles of concave distraction to segmental realignment to a variety of possibilities including the rod rotation manoeuvres, and to segmental approximation via cantilever methods. Additionally, pedicle screw utilization in lumbar curves enhanced correction and stabilization of various deformities, and various studies have strongly supported the clinical advantages of lumbar pedicle screws versus conventional hook instrumentation. Pedicle screw constructs have become increasingly popular in the treatment of patients with spinal deformity. When applied to adolescent idiopathic scoliosis patients, pedicle screw fixation has demonstrated increased corrective ability compared with traditional hook/hybrid instrumentation. In our study, we do a retrospective review of idiopathic scoliosis patients (King 2-Lenke 1 B/C) treated with a selective thoracic posterior fusion using an all-screw construct versus a hybrid (pedicle screws and hooks) construct and, compare the percentage of correction of the scoliotic curves obtained with screws alone and screws and hooks. Special attention was given to the rod diameter and correction technique. Our results show that the percentage of correction of idiopathic thoracic scoliosis is similar when treating the scoliosis with rods and screws alone or with rods, screws and hooks; therefore, we and the majority of authors in the literature do not consider the rod section. This can be an important parameter in the evaluation of the superiority of treatment with screws only or screws and hooks. In our study, even if not of statistical significance, the better thoracic curve correction obtained with the hybrid group should be ascribed to the fact that in this group mostly 6 mm rods were used.

  6. A Case of Implant Failure in Partial Wrist Fusion Applying Magnesium-Based Headless Bone Screws

    PubMed Central

    Emmerich, Judith

    2016-01-01

    This article presents a case of implant failure resulting in mechanical instability of a scaphotrapezotrapezoideal arthrodesis using magnesium-based headless bone screws. During revision surgery osteolysis surrounding the screws was observed as well as degraded screw threads already in existence at 6 weeks after implantation. The supposed osseous integration attributed to magnesium-based screws could not be reproduced in this particular case. Thus, it can be reasoned that the use of magnesium-based screws for partial wrist arthrodesis cannot be encouraged, at least not in dual use. PMID:27800201

  7. Covering the Screw-Access Holes of Implant Restorations in the Esthetic Zone: A Clinical Report

    PubMed Central

    Saboury, Abolfazl; Gooya, Ali

    2014-01-01

    Screw-retained implant restorations have an advantage of predictable retention as well as retrievability, and obviate the risk of excessive sub-gingival cement commonly associated with cement retained implant restorations. Screw-retained restorations generally have screw access holes, which can compromise esthetics and weaken the porcelain around the holes. The purpose of this study is to describe the use of a separate overcasting crown design to cover the screw access hole of implant screw-retained prosthesis for improved esthetics. PMID:25628703

  8. Use of computational fluid dynamics simulations for design of a pretreatment screw conveyor reactor.

    PubMed

    Berson, R Eric; Hanley, Thomas R

    2005-01-01

    Computational fluid dynamics simulations were employed to compare performance of various designs of a pretreatment screw conveyor reactor. The reactor consisted of a vertical screw used to create cross flow between the upward conveying solids and the downward flow of acid. Simulations were performed with the original screw design and a modified design in which the upper flights of the screw were removed. Results of the simulations show visually that the modified design provided favorable plug flow behavior within the reactor. Pressure drop across the length of the reactor without the upper screws in place was predicted by the simulations to be 5 vs 40 kPa for the original design.

  9. Cellulose and the twofold screw axis: Modeling and experimental arguments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crystallography indicates that molecules in crystalline cellulose either have 2-fold screw-axis (21) symmetry or closely approximate it, leading to short distances between H4 and H1' across the glycosidic linkage. Therefore, modeling studies of cellobiose often show elevated energies for 21 structur...

  10. Stability of two-fold screw axis structures for cellulose

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diffraction crystallography indicates that most forms of crystalline cellulose have two-fold screw axis symmetry. Even if exact symmetry is absent, the degree of pseudo symmetry is very high. On the other hand, this symmetry leads to short contacts between H4 and H1' across the glycosidic linkage....

  11. Reprint of: Dynamics of discrete screw dislocations on glide directions

    NASA Astrophysics Data System (ADS)

    Alicandro, R.; De Luca, L.; Garroni, A.; Ponsiglione, M.

    2016-12-01

    We consider a simple discrete model for screw dislocations in crystals. Using a variational discrete scheme we study the motion of a configuration of dislocations toward low energy configurations. We deduce an effective fully overdamped dynamics that follows the maximal dissipation criterion introduced in Cermelli and Gurtin (1999) and predicts motion along the glide directions of the crystal.

  12. Transalveolar screw: a new concept for orthodontic anchorage.

    PubMed

    Hernández-Alfaro, Federico; Egio, Elisabeth; Ruiz, Vanessa

    2009-04-01

    The purpose of this article is to describe the use of a new trans-alveolar screw (TAS) as a temporary orthodontic anchorage device for the posterior maxilla, to intrude overerupted maxillary molars. To date, five consecutive patients have been treated with these newly designed screws. Intrusions achieved ranged from 2.1 and 6mm (mean 4.7 mm). The TAS is cheap, easy to place and remove by the orthodontist, has bicortical anchorage, and is loaded on both sides. The main advantage of TAS is that when placed in the maxilla to intrude upper molars, it allows application of intrusive force from both buccal and palatal aspects simultaneously, so that the line of force in relation to the center of resistance of the posterior segment, permits an in-mass intrusion, avoiding buccal tipping or rotations. Moreover the surgical procedure for inserting and removing the bicortical screw is simple and does not require any surgical flap, so complications are minimal and screws can be loaded immediately, without requiring any waiting healing period of time.

  13. Some refinements of the theory of the viscous screw pump.

    NASA Technical Reports Server (NTRS)

    Elrod, H. G.

    1972-01-01

    Recently performed analysis for herringbone thrust bearings has been incorporated into the theory of the viscous screw pump for Newtonian fluids. In addition, certain earlier corrections for sidewall and channel curvature effects have been simplified. The result is a single, refined formula for the prediction of the pressure-flow relation for these pumps.

  14. [The effect of polylactide screws on fracture healing].

    PubMed

    Duan, H; Song, Y; Peng, Z; Liu, L; Xiong, C; Zhang, X; Luo, F; Zhu, X; Lin, D

    2000-12-01

    This experiment aimed at investigating the effect of a kind of home-bred poly-DL-lactide screws on fracture healing. An operation was performed so as to make bilateral lateral condylar fractures of the femur in 8 dogs. The left sides were fixed with 2 home-bred PDLLA(Mv = 43 x 10(4)) screws, and the contralateral sides were fixed with 2 metalic screws to be used as controls. The animals were sacrificed at 2, 4, 8, and 12 weeks after surgery. Optic microscopy and SEM photography were done. The results of optic microscopy showed that fibrous callus formed already in both groups by 2 weeks after surgery, and bilateral fractures united uneventfully by 12 weeks. Although the course of fracture healing in experimental group was slower than that in control group, the osteogenesis in experimental group appeared to be normal. The SEM examination demonstrated that collagenous fibers arranged regularly and calcified normally in both groups at 12 weeks. And many square and rhomboid granules produced from the degradation of PDLLA material were found in experimental group at 12 weeks. Therefore, it is suggested that this kind of home-bred PDLLA screws should be applicable to fractures where the tissues are rich in blood supply.

  15. Dynamics of discrete screw dislocations on glide directions

    NASA Astrophysics Data System (ADS)

    Alicandro, R.; De Luca, L.; Garroni, A.; Ponsiglione, M.

    2016-07-01

    We consider a simple discrete model for screw dislocations in crystals. Using a variational discrete scheme we study the motion of a configuration of dislocations toward low energy configurations. We deduce an effective fully overdamped dynamics that follows the maximal dissipation criterion introduced in Cermelli and Gurtin (1999) and predicts motion along the glide directions of the crystal.

  16. INTERIOR VIEW OF JAMES HARRIS CUTTING SCREW THREADS INTO THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF JAMES HARRIS CUTTING SCREW THREADS INTO THE INTERIOR OF FITTINGS ON ONE IN A BANK OF TAPPING MACHINES, EACH OPERATED BY THE SAME WORKER SIMULTANEOUSLY BUT TIMED TO REQUIRE WORKER ACTION AT INTERVALS THAT DO NOT INTERFERE WITH THE OTHER MACHINES. - Stockham Pipe & Fittings Company, Tapping Room, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  17. Granulation of increasingly hydrophobic formulations using a twin screw granulator.

    PubMed

    Yu, Shen; Reynolds, Gavin K; Huang, Zhenyu; de Matas, Marcel; Salman, Agba D

    2014-11-20

    The application of twin screw granulation in the pharmaceutical industry has generated increasing interest due to its suitability for continuous processing. However, an understanding of the impact of formulation properties such as hydrophobicity on intermediate and finished product quality has not yet been established. Hence, the current work investigated the granulation behaviour of three formulations containing increasing amounts of hydrophobic components using a Consigma™-1 twin screw granulator. Process conditions including powder feed rate, liquid to solid ratio, granulation liquid composition and screw configuration were also evaluated. The size of the wet granules was measured in order to enable exploration of granulation behaviour in isolation without confounding effects from downstream processes such as drying. The experimental observations indicated that the granulation process was not sensitive to the powder feed rate. The hydrophobicity led to heterogeneous liquid distribution and hence a relatively large proportion of un-wetted particles. Increasing numbers of kneading elements led to high shear and prolonged residence time, which acted to enhance the distribution of liquid and feeding materials. The bimodal size distributions considered to be characteristic of twin screw granulation were primarily ascribed to the breakage of relatively large granules by the kneading elements.

  18. Distal clavicle osteolysis unrelated to trauma, overuse, or metabolic disease.

    PubMed

    Hawkins, B J; Covey, D C; Thiel, B G

    2000-01-01

    Osteolysis of the distal clavicle has been reported to occur from traumatic, atraumatic (overuse), or systemic causes. Three patients with bilateral osteolysis of the distal clavicles whose osteolysis did not fit these etiologic categories were evaluated. Clinical, imaging, and laboratory evaluations were nonspecific, and histologic sections of the distal clavicle showed evidence of chronic inflammation with reactive change of the articular surface. Patients either had complete resolution or marked improvement of their symptoms after bilateral distal clavicle resection at mean followup of 5 years 3 months. These cases of osteolysis of the distal clavicle represent a category of this disorder not previously described.

  19. The general theory of blade screws including propellers, fans, helicopter screws, helicoidal pumps, turbo-motors, and different kinds of helicoidal blades

    NASA Technical Reports Server (NTRS)

    De Bothezat, George

    1920-01-01

    Report presents a theory which gives a complete picture and an exact quantitative analysis of the whole phenomenon of the working of blade screws, but also unites in a continuous whole the entire scale of states of work conceivable for a blade screw. Chapter 1 is devoted to the establishment of the system of fundamental equations relating to the blade screw. Chapter 2 contains the general discussion of the 16 states of work which may establish themselves for a blade screw. The existence of the vortex ring state and the whirling phenomenon are established. All the fundamental functions which enter the blade-screw theory are submitted to a general analytical discussion. The general outline of the curve of the specific function is examined. Two limited cases of the work of the screw, the screw with a zero constructive pitch and the screw with an infinite constructive pitch, are pointed out. Chapter 3 is devoted to the study of the propulsive screw or propeller. (author)

  20. Do biodegradable magnesium alloy intramedullary interlocking nails prematurely lose fixation stability in the treatment of tibial fracture? A numerical simulation.

    PubMed

    Wang, Haosen; Hao, Zhixiu; Wen, Shizhu

    2017-01-01

    Intramedullary interlocking nailing is an effective technique used to treat long bone fractures. Recently, biodegradable metals have drawn increased attention as an intramedullary interlocking nailing material. In this study, numerical simulations were implemented to determine whether the degradation rate of magnesium alloy makes it a suitable material for manufacturing biodegradable intramedullary interlocking nails. Mechano-regulatory and bone-remodeling models were used to simulate the fracture healing process, and a surface corrosion model was used to simulate intramedullary rod degradation. The results showed that magnesium alloy intramedullary rods exhibited a satisfactory degradation rate; the fracture healed and callus enhancement was observed before complete dissolution of the intramedullary rod. Delayed magnesium degradation (using surface coating techniques) did not confer a significant advantage over the non-delayed degradation process; immediate degradation also achieved satisfactory healing outcomes. However, delayed degradation had no negative effect on callus enhancement, as it did not cause signs of stress shielding. To avoid risks of individual differences such as delayed union, delayed degradation is recommended. Although the magnesium intramedullary rod did not demonstrate rapid degradation, its ability to provide high fixation stiffness to achieve earlier load bearing was inferior to that of the conventional titanium alloy and stainless steel rods. Therefore, light physiological loads should be ensured during the early stages of healing to achieve bony healing; otherwise, with increased loading and degraded intramedullary rods, the fracture may ultimately fail to heal.

  1. [Application of the method of anatomic coracoclavicular ligament reconstruction for distal clavicle fractures].

    PubMed

    Fang, J H; Tang, G L; Chen, H; Song, L J; Li, X

    2017-04-04

    Objective: To assess the clinical results of the method of anatomic coracoclavicular ligament reconstruction for distal clavicle fractures. Methods: From August 2013 to January 2015, the super image system was used to measure the CT data of 16 patients suffering distal clavicle fractures before operation in Department of Orthopaedics , the First Affiliated Hospital of Nanjing Medical Univerisity. The fractures' morphological features and acromioclavicular dislocation degree were assessed. By referring to the data collected by the my research group on Chinese people's coracoclavicular ligament, the injuries of the coracoclavicular ligament were estimated, which was then to verify the actual injuries detected during operation. Coracoclavicular ligament reconstruction was performed on patients and screws or suture anchors fixing small bone blocks was used as an adjuvant therapy. Clinical and radiological follow-up was at 1, 3, 6 and 12 months after the procedure. The clinical outcomes were assessed pre- and postoperatively with Constant Scores. Anteroposterior radiographs for the bilateral acromioclavicular joints were obtained immediately after surgery and every follow-up.To compare the reduction maintenance, coracoclavicular distances of the injured shoulders were measured in preoperative and postoperative standard radiographs. Results: All patients received satisfactory fracture and acromioclavicular joint reduction. The average follow-up period was (12.6±3.9) months (ranging from 6 to 22 months). Fractures healed six months after the operation. The coracoclavicular distances increased from (7.8±1.4)mm at one month follow-up to (7.9±1.2)mm at the final follow-up (P>0.05), which could be considered as no difference statistically. The constant score significantly increased from (49.1±4.4) at one month follow-up to (93.8±2.1) at the final evaluation (P<0.001). Obvious loss of acromioclavicular joint reduction was not observed after the operation. Coracoid process

  2. Clinical outcomes of locked plating of distal femoral fractures in a retrospective cohort

    PubMed Central

    2013-01-01

    Purpose Locked plating (LP) of distal femoral fractures has become very popular. Despite technique suggestions from anecdotal and some early reports, knowledge about risk factors for failure, nonunion (NU), and revision is limited. The purpose of this study was to analyze the complications and clinical outcomes of LP treatment for distal femoral fractures. Materials and methods From two trauma centers, 243 consecutive surgically treated distal femoral fractures (AO/OTA 33) were retrospectively identified. Of these, 111 fractures in 106 patients (53.8% female) underwent locked plate fixation. They had an average age of 54 years (range 18 to 95 years): 34.2% were obese, 18.9% were smokers, and 18.9% were diabetic. Open fractures were present in 40.5% with 79.5% Gustilo type III. Fixation constructs for plate length, working length, and screw concentration were delineated. Nonunion and/or infection, and implant failure were used as outcome complication variables. Outcome was based on surgical method and addressed according to Pritchett for reduction, range of motion, and pain. Results Eighty-three (74.8%) of the fractures healed after the index procedure. Twenty (18.0%) of the patients developed a NU. Four of 20 (20%) resulted in a recalcitrant NU. Length of comminution did not correlate to NU (p = 0.180). Closed injuries had a higher tendency to heal after the index procedure than open injuries (p = 0.057). Closed and minimally open (Gustilo/Anderson types I and II) fractures healed at a significantly higher rate after the index procedure compared to type III open fractures (80.0% versus 61.3%, p = 0.041). Eleven fractures (9.9%) developed hardware failure. Fewer nonunions were found in the submuscular group (10.7%) compared to open reduction (32.0%) (p = 0.023). Fractures above total knee arthroplasties had a significantly greater rate of failed hardware (p = 0.040) and worse clinical outcome according to Pritchett (p = 0.040). Loss of

  3. Triangular Fixation Technique for Bicolumn Restoration in Treatment of Distal Humerus Intercondylar Fracture

    PubMed Central

    Kang, Seung-Hoon; Jeong, Min; Lim, Hae-Seong

    2016-01-01

    Background Distal humerus intercondylar fractures are intra-articular and comminuted fractures involving soft tissue injury. As distal humerus is triangle-shaped, parallel plating coupled with articular fixation would be suitable for bicolumn restoration in treatment of distal humerus intercondylar fracture. Methods This study included 38 patients (15 males and 23 females) who underwent olecranon osteotomy, open reduction and internal fixation with the triangle-shaped cannulated screw and parallel locking plates (triangular fixation technique). Functional results were assessed with the visual analog scale (VAS) scores, Mayo elbow performance (MEP) scores and Disabilities of the Arm, Shoulder and Hand (DASH) questionnaires. Anteroposterior and lateral elbow radiographs were assessed for reduction, alignment, fracture union, posttraumatic arthrosis, and heterotopic ossification, and computed tomography (CT) scans were used to obtain more accurate measurements of articular discrepancy. Results All fractures healed primarily with no loss of reduction. The mean VAS, MEP, and DASH scores of the affected elbow were not significantly different from those of the unaffected elbow (p = 0.140, p = 0.090, and p = 0.262, respectively). The mean degree of flexion was significantly lower in the affected elbow than in the unaffected elbow, but was still considered as functional (p = 0.001, > 100° in 33 of 38 patients). Two cases of articular step-offs (> 2 mm) were seen on follow-up CT scans, but not significantly higher in the affected elbow than in the unaffected elbow (p = 0.657). Binary logistic regression analysis revealed that only Association for Osteosynthesis (AO) type C3 fractures correlated with good/excellent functional outcome (p = 0.012). Complications occurred in 12 of the 38 patients, and the overall reoperation rate for complications was 10.5% (4 of 38 patients). Conclusions Triangular fixation technique for bicolumn restoration was an effective and reliable

  4. Dynamic Covalent Synthesis of Aryleneethynylene Cages through Alkyne Metathesis: Dimer, Tetramer, or Interlocked Complex?

    SciTech Connect

    Wang, Qi; Yu, Chao; Zhang, Chenxi; Long, Hai; Azarnoush, Setareh; Jin, Yinghua; Zhang, Wei

    2016-05-01

    A dynamic covalent approach towards rigid aryleneethynylene covalent organic polyhedrons (COPs) was explored. Our study on the relationship of the COP structures and the geometry of their building blocks reveals that the topology of aryleneethynylene COPs strongly depends on the size of the building blocks. A tetramer (D2h symmetric), dimer, or interlocked complex can be formed from monomers with the same face-to-edge angle but in different sizes. As alkyne metathesis is a self-exchange reaction and non-directional, the cyclooligomerization of multi-alkyne monomers involves both intramolecular cyclization and intermolecular metathesis reaction, resulting in complicated thermodynamic process disturbed by kinetic competition. Although a tetrahedron-shaped tetramer (Td symmetric) has comparable thermodynamic stability to a D2h symmetric tetramer, its formation is kinetically disfavored and was not observed experimentally. Aryleneethynylene COPs consist of purely unsaturated carbon backbones and exhibit large internal cavities, which would have interesting applications in host-guest chemistry and development of porous materials.

  5. Giant tunneling piezoresistance of composite elastomers with interlocked microdome arrays for ultrasensitive and multimodal electronic skins.

    PubMed

    Park, Jonghwa; Lee, Youngoh; Hong, Jaehyung; Ha, Minjeong; Jung, Young-Do; Lim, Hyuneui; Kim, Sung Youb; Ko, Hyunhyub

    2014-05-27

    The development of flexible electronic skins with high sensitivities and multimodal sensing capabilities is of great interest for applications ranging from human healthcare monitoring to robotic skins to prosthetic limbs. Although piezoresistive composite elastomers have shown great promise in this area of research, typically poor sensitivities and low response times, as well as signal drifts with temperature, have prevented further development of these materials in electronic skin applications. Here, we introduce and demonstrate a design of flexible electronic skins based on composite elastomer films that contain interlocked microdome arrays and display giant tunneling piezoresistance. Our design substantially increases the change in contact area upon loading and enables an extreme resistance-switching behavior (ROFF/RON of ∼10(5)). This translates into high sensitivity to pressure (-15.1 kPa(-1), ∼0.2 Pa minimum detection) and rapid response/relaxation times (∼0.04 s), with a minimal dependence on temperature variation. We show that our sensors can sensitively monitor human breathing flows and voice vibrations, highlighting their potential use in wearable human-health monitoring systems.

  6. A flexible and highly sensitive strain-gauge sensor using reversible interlocking of nanofibres

    NASA Astrophysics Data System (ADS)

    Pang, Changhyun; Lee, Gil-Yong; Kim, Tae-Il; Kim, Sang Moon; Kim, Hong Nam; Ahn, Sung-Hoon; Suh, Kahp-Yang

    2012-09-01

    Flexible skin-attachable strain-gauge sensors are an essential component in the development of artificial systems that can mimic the complex characteristics of the human skin. In general, such sensors contain a number of circuits or complex layered matrix arrays. Here, we present a simple architecture for a flexible and highly sensitive strain sensor that enables the detection of pressure, shear and torsion. The device is based on two interlocked arrays of high-aspect-ratio Pt-coated polymeric nanofibres that are supported on thin polydimethylsiloxane layers. When different sensing stimuli are applied, the degree of interconnection and the electrical resistance of the sensor changes in a reversible, directional manner with specific, discernible strain-gauge factors. The sensor response is highly repeatable and reproducible up to 10,000 cycles with excellent on/off switching behaviour. We show that the sensor can be used to monitor signals ranging from human heartbeats to the impact of a bouncing water droplet on a superhydrophobic surface.

  7. Laboratory analysis of the infiltration capacity of interlocking concrete block pavements in car parks.

    PubMed

    Sañudo-Fontaneda, Luis A; Rodriguez-Hernandez, Jorge; Vega-Zamanillo, Angel; Castro-Fresno, Daniel

    2013-01-01

    Interlocking concrete block pavements (ICBPs) have been widely used in car parks to reduce runoff. Researches have demonstrated that clogging is the most influential factor in the reduction of the infiltration capacity of this type of permeable pavement. Nevertheless, there is no laboratory study of the infiltration performance of ICBPs that combines clogging levels with variables related with the topography of car parks such as runoff surface length (R(SL)) and surface slope (S(S)). This paper studies the infiltration behaviour of ICBP during their operational life in a car park using an improved version of the Cantabrian Fixed (CF) Infiltrometer. This laboratory device simulates direct rainfall and runoff from adjacent impervious areas over an ICBPs surface of 0.25 m(2) for different slopes (0, 3, 5, 7 and 10%) and three scenarios of clogging (surface newly built, surface clogged and surface clogged with maintenance). This paper presents the results of the tests and a statistical analysis based on three regression models (corresponding to each clogging scenario) depending on the R(SL) and S(S) variables. All models passed a confidence level of 95%, presenting high R(2) values and showing that R(SL) is a more influential variable than the S(S) for all clogging scenarios.

  8. Evidence for halogen bond covalency in acyclic and interlocked halogen-bonding receptor anion recognition

    DOE PAGES

    Robinson, Sean W.; Mustoe, Chantal L.; White, Nicholas G.; ...

    2014-12-05

    The synthesis and anion binding properties of novel halogen-bonding (XB) bis-iodotriazole-pyridinium-containing acyclic and [2]catenane anion host systems are described. The XB acyclic receptor displays selectivity for acetate over halides with enhanced anion recognition properties compared to the analogous hydrogen-bonding (HB) acyclic receptor. A reversal in halide selectivity is observed in the XB [2]catenane, in comparison to the acyclic XB receptor, due to the interlocked host’s unique three-dimensional binding cavity, and no binding is observed for oxoanions. Notable halide anion association constant values determined for the [2]catenane in competitive organic–aqueous solvent mixtures demonstrate considerable enhancement of anion recognition as compared tomore » the HB catenane analogue. X-ray crystallographic analysis of a series of halide catenane complexes reveal strong XB interactions in the solid state. These interactions were studied using Cl and Br K-edge X-ray Absorption Spectroscopy (XAS) indicating intense pre-edge features characteristic of charge transfer from the halide to its bonding partner (σAX←X–* ← X1s), and providing a direct measure of the degree of covalency in the halogen bond(s). Lastly, the data reveal that the degree of covalency is similar to that which is observed in transition metal coordinate covalent bonds. These results are supported by DFT results, which correlate well with the experimental data.« less

  9. Evidence for halogen bond covalency in acyclic and interlocked halogen-bonding receptor anion recognition

    SciTech Connect

    Robinson, Sean W.; Mustoe, Chantal L.; White, Nicholas G.; Brown, Asha; Thompson, Amber L.; Kennepohl, Pierre; Beer, Paul D.

    2014-12-05

    The synthesis and anion binding properties of novel halogen-bonding (XB) bis-iodotriazole-pyridinium-containing acyclic and [2]catenane anion host systems are described. The XB acyclic receptor displays selectivity for acetate over halides with enhanced anion recognition properties compared to the analogous hydrogen-bonding (HB) acyclic receptor. A reversal in halide selectivity is observed in the XB [2]catenane, in comparison to the acyclic XB receptor, due to the interlocked host’s unique three-dimensional binding cavity, and no binding is observed for oxoanions. Notable halide anion association constant values determined for the [2]catenane in competitive organic–aqueous solvent mixtures demonstrate considerable enhancement of anion recognition as compared to the HB catenane analogue. X-ray crystallographic analysis of a series of halide catenane complexes reveal strong XB interactions in the solid state. These interactions were studied using Cl and Br K-edge X-ray Absorption Spectroscopy (XAS) indicating intense pre-edge features characteristic of charge transfer from the halide to its bonding partner (σAX←X–* ← X1s), and providing a direct measure of the degree of covalency in the halogen bond(s). Lastly, the data reveal that the degree of covalency is similar to that which is observed in transition metal coordinate covalent bonds. These results are supported by DFT results, which correlate well with the experimental data.

  10. A bio-inspired swellable microneedle adhesive for mechanical interlocking with tissue

    NASA Astrophysics Data System (ADS)

    Yang, Seung Yun; O'Cearbhaill, Eoin D.; Sisk, Geoffroy C.; Park, Kyeng Min; Cho, Woo Kyung; Villiger, Martin; Bouma, Brett E.; Pomahac, Bohdan; Karp, Jeffrey M.

    2013-04-01

    Achieving significant adhesion to soft tissues while minimizing tissue damage poses a considerable clinical challenge. Chemical-based adhesives require tissue-specific reactive chemistry, typically inducing a significant inflammatory response. Staples are fraught with limitations including high-localized tissue stress and increased risk of infection, and nerve and blood vessel damage. Here inspired by the endoparasite Pomphorhynchus laevis, which swells its proboscis to attach to its host’s intestinal wall, we have developed a biphasic microneedle array that mechanically interlocks with tissue through swellable microneedle tips, achieving ~3.5-fold increase in adhesion strength compared with staples in skin graft fixation, and removal force of ~4.5 N cm-2 from intestinal mucosal tissue. Comprising a poly(styrene)-block-poly(acrylic acid) swellable tip and non-swellable polystyrene core, conical microneedles penetrate tissue with minimal insertion force and depth, yet high adhesion strength in their swollen state. Uniquely, this design provides universal soft tissue adhesion with minimal damage, less traumatic removal, reduced risk of infection and delivery of bioactive therapeutics.

  11. A Bio-Inspired Swellable Microneedle Adhesive for Mechanical Interlocking with Tissue

    PubMed Central

    Yang, Seung Yun; O'Cearbhaill, Eoin D.; Sisk, Geoffroy C.; Park, Kyeng Min; Cho, Woo Kyung; Villiger, Martin; Bouma, Brett E.; Pomahac, Bohdan; Karp, Jeffrey M.

    2013-01-01

    Achieving significant adhesion to soft tissues while minimizing tissue damage poses a considerable clinical challenge. Chemical-based adhesives require tissue-specific reactive chemistry, typically inducing a significant inflammatory response. Staples are fraught with limitations including high-localized tissue stress and increased risk of infection, and nerve and blood vessel damage. Here, inspired by the endoparasite Pomphorhynchus laevis which swells its proboscis to attach to its host’s intestinal wall, we have developed a biphasic microneedle array that mechanically interlocks with tissue through swellable microneedle tips, achieving ~ 3.5 fold increase in adhesion strength compared to staples in skin graft fixation, and removal force of ~ 4.5 N/cm2 from intestinal mucosal tissue. Comprising a poly(styrene)-block-poly(acrylic acid) swellable tip and non-swellable polystyrene core, conical microneedles penetrate tissue with minimal insertion force and depth, yet high adhesion strength in their swollen state. Uniquely, this design provides universal soft tissue adhesion with minimal damage, less traumatic removal, reduced risk of infection and delivery of bioactive therapeutics. PMID:23591869

  12. Mechanically interlocked daisy-chain-like structures as multidimensional molecular muscles

    NASA Astrophysics Data System (ADS)

    Chang, Jia-Cheng; Tseng, Shin-Han; Lai, Chien-Chen; Liu, Yi-Hung; Peng, Shie-Ming; Chiu, Sheng-Hsien

    2016-09-01

    Daisy chains (DCs) are garlands of flowers that can be worn as bracelets and necklaces. As a result of their beautiful interlocked structures and possible muscle-like motions, cyclic molecular DCs ([cn]DCs, where n is the number of repeating units) have long been attractive synthetic targets for supramolecular chemists. Herein we report artificial molecular muscles that—unlike one-dimensional (1D) biological muscles—contract and stretch in 2D or 3D. These systems have the structures of [c3]- and [c4]DCs with subcomponents that operate as molecular switches, powered through the addition or removal of Zn2+ ions to impart muscle-like behaviour. We assembled these [c3]- and [c4]DCs selectively by exploiting structural rigidity, coordination geometries and bond rotational barriers that disfavoured the formation of smaller homologues. The switching phenomena of our [c3]- and [c4]DCs resulted in the contracted molecular muscles stretching by approximately 23 and 36%, respectively, comparable to the value (27%) for linear biological muscles.

  13. Assembly of porous smectic structures formed from interlocking high-symmetry planar nanorings

    PubMed Central

    Jackson, George; Müller, Erich A.; Escobedo, Fernando A.

    2016-01-01

    Materials comprising porous structures, often in the form of interconnected concave cavities, are typically assembled from convex molecular building blocks. The use of nanoparticles with a characteristic nonconvex shape provides a promising strategy to create new porous materials, an approach that has been recently used with cagelike molecules to form remarkable liquids with “scrabbled” porous cavities. Nonconvex mesogenic building blocks can be engineered to form unique self-assembled open structures with tunable porosity and long-range order that is intermediate between that of isotropic liquids and of crystalline solids. Here we propose the design of highly open liquid-crystalline structures from rigid nanorings with ellipsoidal and polygonal geometry. By exploiting the entropic ordering characteristics of athermal colloidal particles, we demonstrate that high-symmetry nonconvex rings with large internal cavities interlock within a 2D layered structure leading to the formation of distinctive liquid-crystalline smectic phases. We show that these smectic phases possess uniquely high free volumes of up to ∼95%, a value significantly larger than the 50% that is typically achievable with smectic phases formed by more conventional convex rod- or disklike mesogenic particles. PMID:27540114

  14. Segmented instrumentation tube including a locking sleeve for interlocking the segments of the instrumentation tube

    DOEpatents

    Obermeyer, F.D.

    1993-11-16

    Segmented instrumentation tube including a locking sleeve for interlocking the segments of the instrumentation tube, so that the threaded ends of the instrumentation tube do not unthread when subjected to vibration, such an instrumentation tube being suitable for use in a nuclear reactor pressure vessel. The instrumentation tube has a first member having a threaded end portion that has a plurality of first holes circumferentially around the outside surface thereof. The instrumentation tube also has a second member having a threaded end portion that has a plurality of second holes circumferentially around the outside surface thereof. The threads of the second member are caused to threadably engage the threads of the first member for defining a threaded joint there between. A sleeve having an inside surface surrounds the end portion of the first member and the end portion of the second member and thus surrounds the threaded joint. The sleeve includes a plurality of first projections and second projections that outwardly extend from the inside surface to engage the first holes and the second holes, respectively. The outside surface of the sleeve is crimped or swaged at the locations of the first projections and second projections such that the first projections and the second projections engage their respective holes. In this manner, independent rotation of the first member with respect to the second member is prevented, so that the instrumentation tube will not unthread at its threaded joint. 10 figures.

  15. Segmented instrumentation tube including a locking sleeve for interlocking the segments of the instrumentation tube

    DOEpatents

    Obermeyer, Franklin D.

    1993-01-01

    Segmented instrumentation tube including a locking sleeve for interlocking the segments of the instrumentation tube, so that the threaded ends of the instrumentation tube do not unthread when subjected to vibration, such an instrumentation tube being suitable for use in a nuclear reactor pressure vessel. The instrumentation tube has a first member having a threaded end portion that has a plurality of first holes circumferentially around the outside surface thereof. The instrumentation tube also has a second member having a threaded end portion that has a plurality of second holes circumferentially around the outside surface thereof. The threads of the second member are caused to threadably engage the threads of the first member for defining a threaded joint therebetween. A sleeve having an inside surface surrounds the end portion of the first member and the end portion of the second member and thus surrounds the threaded joint. The sleeve includes a plurality of first projections and second projections that outwardly extend from the inside surface to engage the first holes and the second holes, respectively. The outside surface of the sleeve is crimped or swaged at the locations of the first projections and second projections such that the first projections and the second projections engage their respective holes. In this manner, independent rotation of the first member with respect to the second member is prevented, so that the instrumentation tube will not unthread at its threaded joint.

  16. Evaluation of different screw fixation techniques and screw diameters in sagittal split ramus osteotomy: finite element analysis method.

    PubMed

    Sindel, A; Demiralp, S; Colok, G

    2014-09-01

    Sagittal split ramus osteotomy (SSRO) is used for correction of numerous congenital or acquired deformities in facial region. Several techniques have been developed and used to maintain fixation and stabilisation following SSRO application. In this study, the effects of the insertion formations of the bicortical different sized screws to the stresses generated by forces were studied. Three-dimensional finite elements analysis (FEA) and static linear analysis methods were used to investigate difference which would occur in terms of forces effecting onto the screws and transmitted to bone between different application areas. No significant difference was found between 1·5- and 2-mm screws used in SSRO fixation. Besides, it was found that 'inverted L' application was more successful compared to the others and that was followed by 'L' and 'linear' formations which showed close rates to each other. Few studies have investigated the effect of thickness and application areas of bicortical screws. This study was performed on both advanced and regressed jaws positions.

  17. Accuracy of robot-assisted pedicle screw placement for adolescent idiopathic scoliosis in the pediatric population.

    PubMed

    Macke, Jeremy J; Woo, Raymund; Varich, Laura

    2016-06-01

    This is a retrospective review of pedicle screw placement in adolescent idiopathic scoliosis (AIS) patients under 18 years of age who underwent robot-assisted corrective surgery. Our primary objective was to characterize the accuracy of pedicle screw placement with evaluation by computed tomography (CT) after robot-assisted surgery in AIS patients. Screw malposition is the most frequent complication of pedicle screw placement and is more frequent in AIS. Given the potential for serious complications, the need for improved accuracy of screw placement has spurred multiple innovations including robot-assisted guidance devices. No studies to date have evaluated this robot-assisted technique using CT exclusively within the AIS population. Fifty patients were included in the study. All operative procedures were performed at a single institution by a single pediatric orthopedic surgeon. We evaluated the grade of screw breach, the direction of screw breach, and the positioning of the patient for preoperative scan (supine versus prone). Of 662 screws evaluated, 48 screws (7.2 %) demonstrated a breach of greater than 2 mm. With preoperative prone position CT scanning, only 2.4 % of screws were found to have this degree of breach. Medial malposition was found in 3 % of screws, a rate which decreased to 0 % with preoperative prone position scanning. Based on our results, we conclude that the proper use of image-guided robot-assisted surgery can improve the accuracy and safety of thoracic pedicle screw placement in patients with adolescent idiopathic scoliosis. This is the first study to evaluate the accuracy of pedicle screw placement using CT assessment in robot-assisted surgical correction of patients with AIS. In our study, the robot-assisted screw misplacement rate was lower than similarly constructed studies evaluating conventional (non-robot-assisted) procedures. If patients are preoperatively scanned in the prone position, the misplacement rate is further

  18. Biomechanical analysis of forces sustained by iliac screws in spinal instrumentation for deformity treatment: preliminary results.

    PubMed

    Perrault, Frederique D; Aubin, Carl-Eric; Wang, Xiaoyu; Schwend, Richard M

    2012-01-01

    Iliac screws used in long instrumentation for deformity treatment are subject to large forces, which may sometimes lead to fixation failures (intra- and postoperatively). The objective of this study was to analyze the biomechanics of iliac screw fixations. The study was based on a patient-specific simulation of a neuromuscular scoliosis case with a long instrumentation to the pelvis. A multi body flexible model was created using a preoperative 3D reconstructed spine and pelvis. The side bending radiographs were used to personalize the mechanical properties. The instrumentation construct was modeled as rigid bodies and flexible beams connected by kinematic joints. Three instrumentation parameters were studied: the connector length, the inter rod connectors and the use of sacral screws. The simulations showed that the forces and torques at the iliac screws were lowered by 9% and 25% respectively by reducing the lateral connector length (from 20 to 10 mm). An inter rod connector did not significantly reduce the iliac screw loads. Sacral screws reduced the functional loads on the iliac screws, but hardware related problems may be shifted onto the sacral screws. Sacral screws in conjunction with inter rod connectors reduced the loads at iliac screws without overloading the sacral screws. The preliminary results showed that the forces at the iliac screws could be lowered through different instrumentation parameters. In the next step of the study, the model validation will be further completed and used to evaluate other instrumentation factors by means of an experimental design framework. The knowledge of loading biomechanics at the iliac screw fixation is important for finding solutions to reduce the risk of failure, such as improving preoperative planning, instrumentation techniques and iliac screw construct design.

  19. Subaxial cervical pedicle screw insertion with newly defined entry point and trajectory: accuracy evaluation in cadavers.

    PubMed

    Zheng, Xiujun; Chaudhari, Rahul; Wu, Chunhui; Mehbod, Amir A; Transfeldt, Ensor E

    2010-01-01

    Successful placement of cervical pedicle screws requires accurate identification of both entry point and trajectory. However, literature has not provided consistent recommendations regarding the direction of pedicle screw insertion and entry point location. The objective of this study was to define a guideline regarding the optimal entry point and trajectory in placing subaxial cervical pedicle screws and to evaluate the screw accuracy in cadaver cervical spines. The guideline for entry point and trajectory for each vertebra was established based on the recently published morphometric data. Six fresh frozen cervical spines (C3-C7) were used. There were two men and four women. After posterior exposure, the entry point was determined and the cortical bone of the entry point was removed using a 2-mm burr. Pilot holes were created with a cervical probe based on the guideline using fluoroscopy. After tapping, 3.5-mm screws with appropriate length were inserted. After screw insertion, every vertebra was dissected and inspected for pedicle breach. The pedicle width, height, pedicle transverse angulation and actual screw insertion angle were measured. A total of 60 pedicle screws were inserted. No statistical difference in pedicle width and height was found between the left and right sides for each level. The overall accuracy of pedicle screws was 83.3%. The remaining 13.3% screws had noncritical breach, and 3.3% had critical breach. The critical breach was not caused by the guideline. There was no statistical difference between the pedicle transverse angulation and the actual screw trajectory created using the guideline. There was statistical difference in pedicle width between the breach and non-breach screws. In conclusion, high success rate of subaxial cervical pedicle screw placement can be achieved using the recently proposed operative guideline and oblique views of fluoroscopy. However, careful preoperative planning and good surgical skills are still required to

  20. Pullout strength of anterior spinal instrumentation: a product comparison of seven screws in calf vertebral bodies

    PubMed Central

    Wahl, Dieter; Wild, Alexander; Krauspe, Rüdiger; Schneider, Erich; Linke, Berend

    2007-01-01

    A lot of new implant devices for spine surgery are coming onto the market, in which vertebral screws play a fundamental role. The new screws developed for surgery of spine deformities have to be compared to established systems. A biomechanical in vitro study was designed to assess the bone–screw interface fixation strength of seven different screws used for correction of scoliosis in spine surgery. The objectives of the current study were twofold: (1) to evaluate the initial strength at the bone–screw interface of newly developed vertebral screws (Universal Spine System II) compared to established systems (product comparison) and (2) to evaluate the influence of screw design, screw diameter, screw length and bone mineral density on pullout strength. Fifty-six calf vertebral bodies were instrumented with seven different screws (USS II anterior 8.0 mm, USS II posterior 6.2 mm, KASS 6.25 mm, USS II anterior 6.2 mm, USS II posterior 5.2 mm, USS 6.0 mm, USS 5.0 mm). Bone mineral density (BMD) was determined by quantitative computed tomography (QCT). Failure in axial pullout was tested using a displacement-controlled universal test machine. USS II anterior 8.0 mm showed higher pullout strength than all other screws. The difference constituted a tendency (P = 0.108) when compared to USS II posterior 6.2 mm (+19%) and was significant in comparison to the other screws (+30 to +55%, P < 0.002). USS II posterior 6.2 mm showed significantly higher pullout strength than USS 5.0 mm (+30%, P = 0.014). The other screws did not differ significantly in pullout strength. Pullout strength correlated significantly with BMD (P = 0.0015) and vertebral body width/screw length (P < 0.001). The newly developed screws for spine surgery (USS II) show higher pullout strength when compared to established systems. Screw design had no significant influence on pullout force in vertebral body screws, but outer diameter of the screw, screw length and BMD are good predictors