Sample records for distal interlocking screw

  1. Radiation-free Insertion of Distal Interlocking Screw in Tibial and Femur Nailing: A Simple Technique

    PubMed Central

    Soni, Ritesh Kumar; Mehta, Surender Mohan; Awasthi, Bhanu; Singh, Janith Lal; Kumar, Amit; Thakur, Lokesh; Tripathy, Sujit Kumar

    2012-01-01

    Background: Distal interlocking screw insertion in intramedullary nailing of long-bone fracture is a challenging task for orthopedic surgeons. It is difficult particularly when the surgeon is in his learning stage or when image intensifier is not available. We describe a radiation-free technique of distal interlocking screw insertion which is easy and practicable. Materials and Methods: In this technique, a same length nail is placed over the skin (outer nail) and through its distal-most screw hole, a 3.2 mm drill bit is inserted to drill the distal locking screw hole of the intramedullary nail (inner nail). With a small skin incision over the distal screw holes, the distal-most screw hole is identified; the bone window overlying the screw hole is widened with an awl and a locking bolt is inserted with a washer under direct visualization. The other distal interlocking screw is simply drilled by matching the other three holes of the outer and inner nails. We have operated 86 patients (39 femoral shaft fracture and 47 tibial shaft fracture) in 1 year where this technique was used. There were 41 open fracture and 45 closed fracture. Results: Within 6 months of follow-up, bony union was achieved in 36 of 39 femur fractures and 45 of 47 tibial fractures. No unwanted complications were observed during the postoperative period and in follow-up. Conclusion: This method of radiation-free distal interlocking screw insertion is simple and can be used in third world country where image intensifier facility is not available. However, surgeons are encouraged to use image intensifier facility where the facility is available. PMID:23066456

  2. Stress analysis of the distal locking screws for femoral interlocking nailing.

    PubMed

    Lin, J; Lin, S J; Chen, P Q; Yang, S H

    2001-01-01

    In femoral locked nailing, the distal locking screws are vulnerable to mechanical failure. Biomechanical studies have shown that the stress on these screws is substantially affected by the fit of the nail in the medullary canal. In this study, a "closed form" mathematical model based on elastic beam-column theory was developed to investigate how the nail-cortical contact, which was simulated by a linear elastic foundation, affected the stress on the distal locking screws. Providing data for the model was a construct of a fractured femur with an intramedullary locked nail loaded by an eccentric vertical load. The stress on the locking screw was analyzed as a function of the distance from the fracture to the locking screw in the distal fragment under two situations: with and without nail-cortical contact in the distal fragment. With nail-cortical contact, the screw stress decreased as the length of nail-cortical contact and the distance between the distal locking screw and the fracture site increased, but this stress contrarily increased when the nail reached the femoral region at which the screw length increased. The screw stress was much higher without nail-cortical contact than with contact and continued to increase as the nail was inserted further. The mathematical model developed here can be a convenient means of rapid stress evaluation and parametric analysis for locked femoral nailing. It may be used to improve the design of interlocking nails and surgical technique. PMID:11332621

  3. Perceptions and Realities for Distal Freehand Interlocking of Intramedullary Nails

    PubMed Central

    Ostrum, Robert F.

    2015-01-01

    There is a perception that distal freehand interlocking (DFHI) of intramedullary nails can be difficult and time consuming. This study consists of a survey of surgeons' practices for DFHI screws and their reasons for not using this technique. A survey was sent to 1400 orthopaedic surgeons who were asked to agree or disagree with statements regarding the difficulty and indications for the usage of distal freehand interlocking screws. The results were analyzed by practice demographics, resident availability, and completion of an orthopaedic trauma fellowship. Overall, 316 surgeons (22.6%) responded to the survey. Fellowship trained surgeons were 60% less likely to find DFHI difficult when compared to nonfellowship surgeons and surgeons with residents were 76% less likely to perceive DFHI as difficult than surgeons without residents. In all groups, 40–43% of surgeons used distal interlocking based on their comfort with the technique and not the fracture pattern. Distal freehand interlocking is perceived as difficult by community orthopaedic surgeons without residents and surgeons who have not done an orthopaedic trauma fellowship. Forty percent of surgeons based their usage of DFHI screws on their comfort with the technique and not the fracture pattern. PMID:25945259

  4. Reinforcing the role of the conventional C-arm - a novel method for simplified distal interlocking

    PubMed Central

    2012-01-01

    Background The common practice for insertion of distal locking screws of intramedullary nails is a freehand technique under fluoroscopic control. The process is technically demanding, time-consuming and afflicted to considerable radiation exposure of the patient and the surgical personnel. A new concept is introduced utilizing information from within conventional radiographic images to help accurately guide the surgeon to place the interlocking bolt into the interlocking hole. The newly developed technique was compared to conventional freehand in an operating room (OR) like setting on human cadaveric lower legs in terms of operating time and radiation exposure. Methods The proposed concept (guided freehand), generally based on the freehand gold standard, additionally guides the surgeon by means of visible landmarks projected into the C-arm image. A computer program plans the correct drilling trajectory by processing the lens-shaped hole projections of the interlocking holes from a single image. Holes can be drilled by visually aligning the drill to the planned trajectory. Besides a conventional C-arm, no additional tracking or navigation equipment is required. Ten fresh frozen human below-knee specimens were instrumented with an Expert Tibial Nail (Synthes GmbH, Switzerland). The implants were distally locked by performing the newly proposed technique as well as the conventional freehand technique on each specimen. An orthopedic resident surgeon inserted four distal screws per procedure. Operating time, number of images and radiation time were recorded and statistically compared between interlocking techniques using non-parametric tests. Results A 58% reduction in number of taken images per screw was found for the guided freehand technique (7.4 ± 3.4) (mean ± SD) compared to the freehand technique (17.6 ± 10.3) (p < 0.001). Total radiation time (all 4 screws) was 55% lower for the guided freehand technique compared to conventional freehand (p = 0.001). Operating time per screw (from first shot to screw tightened) was on average 22% reduced by guided freehand (p = 0.018). Conclusions In an experimental setting, the newly developed guided freehand technique for distal interlocking has proven to markedly reduce radiation exposure when compared to the conventional freehand technique. The method utilizes established clinical workflows and does not require cost intensive add-on devices or extensive training. The underlying principle carries potential to assist implant positioning in numerous other applications within orthopedics and trauma from screw insertions to placement of plates, nails or prostheses. PMID:22276698

  5. Screw prominences related to palmar locking plating of distal radius

    Microsoft Academic Search

    T. S. Sügün; N. Karabay; Y. Gürbüz; K. Özaksar; T. Toros; M. Kayalar

    2011-01-01

    Fixation of unstable distal radius fractures with palmar locking plates provides a stable reduction and early return of function, but complications arising from unrecognized dorsally prominent screws penetrating the extensor compartments are increasingly reported. Standard radiographs and fluoroscopy may not adequately visualize screw lengths, owing to the complex shape of the dorsum of the distal radius. We examined 46 distal

  6. Long stemmed total knee arthroplasty with interlocking screws: a computational bone adaptation study.

    PubMed

    Nyman, Jeffry S; Hazelwood, Scott J; Rodrigo, Juan J; Martin, R Bruce; Yeh, Oscar C

    2004-01-01

    The ability of an interlocking screw fixation technique to minimize bone loss related to stress shielding in the tibia was investigated and compared to the abilities of cement and press-fit fixation. Full bony ingrowth has been associated with greater stress shielding than partial ingrowth; therefore, the effect of intimate bonding of the stem to bone on subsequent bone loss was also studied. A damage- and disuse-based remodeling theory was coupled with a two-dimensional finite element model of the tibia to predict changes in bone remodeling following long stemmed total knee arthroplasty (TKA) for four different fixation techniques (cement, press-fit, interlock with bony ingrowth, and interlock without bony ingrowth). Remodeling changes commenced with the model state variables--bone area fraction, mechanical stimulus, damage, and remodeling activity--at steady-state values predicted by the intact tibia simulation. After TKA and irrespective of fixation technique, the model predicted elevated remodeling due to disuse, in which more bone was removed than replenished. In regions below the tibial tray and along the cortices, the interlocking stem with full bony ingrowth and the cemented stem caused the least amount of bone loss. An interlocking stem with a smooth, matted finish did not reduce the bone loss associated with interlocking fixation. PMID:14656659

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

    PubMed

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

    2015-06-01

    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. Absorbable Screws Versus Metallic Screws for Distal Tibiofibular Syndesmosis Injuries: A Meta-Analysis.

    PubMed

    Xie, Yuanlong; Cai, Lin; Deng, Zhouming; Ran, Bing; Hu, Chao

    2015-01-01

    A meta-analysis was performed to investigate the outcomes between absorbable screw (AS) and metallic screw (MS) fixation for distal tibiofibular syndesmosis injuries (DTSIs). Randomized controlled trials comparing AS versus MS fixation in DTSIs were searched systematically, and the outcomes were analyzed using Review Manager Software, version 5.2. The risk ratio (RR) or mean difference with the 95% confidence interval (CI) was calculated using the fixed effects or random effects model. A total of 16 studies were included in the meta-analysis. No statistically significant difference was found between AS and MS fixation in excellent and good functional recovery rate (RR 1.11, 95% CI 1.00 to 1.23, I(2) = 60%, p = .06), infection (RR 1.66, 95% CI 0.73 to 3.79, I(2) = 0%, p = .23), incidence of pain (RR 0.68, 95% CI 0.24 to 1.92, I(2) = 12%, p = .47), screw broken (RR 0.31, 95% CI 0.03 to 2.93, I(2) = %, p = .31), heterotopic ossification (RR 1.93, 95% CI 0.21 to 17.62, I(2) = 51%, p = .56; 472 cases in 4 studies), fracture healing time (mean difference -1.88, 95% CI -3.51 to -0.26, I(2) = 93%, p = .02,), duration of operation time (mean difference 7.64, 95% CI -3.80 to 19.09, I(2) = 98%, p = .19). The incidence of foreign body reaction was higher with AS fixation (RR 6.07, 95% CI 2.54 to 14.50, I(2) = 0%, p < .001). The reoperation rate was higher with MS fixation (RR 0.08, 95% CI 0.03 to 0.18, I(2) = 77%, p < .01). The functional outcomes of AS were as good as those with MS for DTSIs. Other than the foreign body reaction, the complications occurring after AS fixation were not as serious as those with MS fixation. AS fixation might be a preferable alternative for reconstruction of DTSIs. PMID:25956019

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

    Microsoft Academic Search

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

    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

  10. Palmar Fixation of Dorsally Displaced Distal Radius Fractures Using Locking Plates with Smartlock Locking Screws

    Microsoft Academic Search

    T. C. WONG; C. C. YEUNG; Y. CHIU; S. H. YEUNG; F. K. IP

    2009-01-01

    We performed a prospective cohort study on a consecutive series of 35 unstable, dorsally displaced distal radius fractures, which were treated with palmar locking plates and SmartLock locking screws. There were 17 men and 18 women with a mean age of 44 years who were reviewed at a mean follow-up of 10 months. All the fractures healed at a mean

  11. 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. PMID:22158054

  12. 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. PMID:25830256

  13. Radiographic Evaluation of Dorsal Screw Penetration After Volar Fixed-Angle Plating of the Distal Radius: A Cadaveric Study

    Microsoft Academic Search

    Steven D. Maschke; Peter J. Evans; David Schub; Richard Drake; Jeffrey N. Lawton

    2007-01-01

    Introduction  Extensor tendon irritation and attritional tendon ruptures are potentially serious complications after open reduction and\\u000a internal fixation of distal radius fractures. These complications are well recognized after dorsal plating of distal radii;\\u000a and these are now being reported after errant screw placement during volar fixed-angle plating. Intraoperative detection of\\u000a improper screw placement is critical, as corrective action can be taken

  14. Late migration of threaded wire (schanz screw) from right distal clavicle to the cervical spine.

    PubMed

    Tsai, Chun-Hao; Hsu, Horng-Chaung; Huan, Chun-Yin; Chen, Hsien-Te; Fong, Yi-Chin

    2009-01-01

    We report a 49-year-old man who had undergone osteosynthesis to treat right distal clavicular fracture with a threaded wire (Schanz screw). The wire could not be removed due to its firm fixation within the bone. Eight years later, migration of the broken wire to the right 7th cervical vertebra punctured the lamina, with no spinal cord injury noted. The threaded wire was extracted from the C7 lamina emergently. No complication occurred after pin removal or during the 1-year postoperative follow-up. PMID:19181599

  15. 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. PMID:22652178

  16. [Possibilities for improving fatigue properties of interlocking screws of solid tibial nails. A mathematical model with practical conclusions].

    PubMed

    Holper, B; Tschegg, E K; Stanzl-Tschegg, S; Gäbler, C

    2002-02-01

    One major problem using small diameter nails in the treatment of tibial fractures is the high rate of fatigue fractures of the locking screws. The objective of this study was to develop a mathematical model for analysis of the stress concentration factor as well as edge fibre stress. This would allow an analysis of the stress peaks caused by the thread of the screw as well as showing ways to increase the fatigue limits of the screws. The main consideration was the fact that a thread can be calculated like a relief notch used in theory of strength to relieve the strain on building materials. The transformation from one notch to multiple notches obviously reduces the stress concentration factor. To improve the fatigue limit of locking screws one has to modify the stress concentration factor or the edge fibre stress on the implant. Absence of a thread at the location where the screw contacts the nail's aperture (where the main load is transmitted to the screw and where the screw therefore usually tends to break) may double the fatigue strength and fatigue limit by avoiding the negative notch effect of the screw's thread. If this option is not possible one has to consider that the optimal threaded screw should have a minimal edge distance, a high notch radius and a minimal edge depth. PMID:11968541

  17. 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. PMID:24401740

  18. Dorsal tangential view of the wrist to detect screw penetration to the dorsal cortex of the distal radius after volar fixed-angle plating

    Microsoft Academic Search

    Kagan Ozer; Serdar Toker

    2011-01-01

    Background  Extensor tendon irritation and attritional tendon ruptures are well-recognized complications, secondary to dorsal screw penetration\\u000a following volar plating of the distal radius. Lateral and oblique views of the wrist have limited ability to detect such penetration,\\u000a particularly at the ulnar side of the Lister's tubercle. In this report, we conducted an intraoperative fluoroscopic study\\u000a to determine dorsal screw penetration in

  19. Comparison of the tissue response to absorbable self-reinforced polylactide screws and metallic screws in the fixation of cancellous bone osteotomies: an experimental study on the rabbit distal femur.

    PubMed

    Viljanen, J T; Pihlajamäki, H K; Törmälä, P O; Rokkanen, P U

    1997-05-01

    The availability of absorbable fracture-fixation devices for clinical use calls for better knowledge of the reaction of bone tissue to absorbable polyester implants as compared with similar metallic devices. To examine and compare the tissue response to biodegradable and metallic screws within cancellous bone, a transverse transcondylar osteotomy of the distal femur was fixed with absorbable self-reinforced polylevolactide screws in 35 rabbits and with stainless-steel screws in 35 rabbits. New bone formation and consolidation of the osteotomy were examined histologically, histomorphometrically, and microradiographically within standardized sample fields 1, 3, 6, 12, 24, 36, and 48 weeks postoperatively. The intact contralateral femur served as the control. A vigorous osteoconductive response to the polylevolactide screws was observed at 3 weeks postoperatively, and the osteoid surface fraction was significantly higher in all follow-ups than in the contralateral femora. In the femora with metallic screws, new bone formation was seen 3, 6, and 12 weeks postoperatively, but at 24, 36, and 48 weeks the osteoid surface fraction did not differ significantly from that of the intact control femora. The total bone area was significantly larger in the femora with self-reinforced polylevolactide screws than in the control bone 6-48 weeks postoperatively; in the femora with metallic screws, this was found only at 6 and 12 weeks. After 48 weeks, the femora fixed with metallic screws had statistically smaller total bone area than the intact control femora. Solid bone union was seen in 84% of the osteotomies in the self-reinforced polylevolactide group and in 76% of those in the metallic group after 3 weeks or more. No signs of degradation of the self-reinforced polyleuolactide implant and only a mild foreign-body reaction with no accumulations of inflammatory cells to either self-reinforced polylevolactide or metallic screws were observed during the follow-up period. Both types of screws seemed to induce an osteostimulatory response around their threads. This phenomenon was transient for metallic screws but lasted for at least 48 weeks for self-reinforced polylevolactide screws. The polylevolactide screw does not seem to cause osteopenia at the implantation site. The fixation properties of both self-reinforced polylevolactide screws and metallic screws appear to be sufficient for the fixation of small fragments of cancellous bone. PMID:9246086

  20. Modified Pendulum Appliance Including Distal Screw and Uprighting Activation for Non-Compliance Therapy of Class-II Malocclusion in Children and Adolescents

    Microsoft Academic Search

    Gero Kinzinger; Robert Fuhrmann; Ulrich Gross; Peter Diedrich

    2000-01-01

    In present-day orthodontics there is an increasing call for therapeutic procedures and appliances allowing those delivering the treatment maximum independence from patient cooperation. This requires both the development of new therapeutic appliances and the optimization of existing ones (via modification). The present study aims to analyze the therapeutic outcomes obtained by using a pendulum appliance (distal screw and integrated molar

  1. Tangential View and Intraoperative Three-Dimensional Fluoroscopy for the Detection of Screw-Misplacements in Volar Plating of Distal Radius Fractures

    PubMed Central

    Rausch, Sascha; Marintschev, Ivan; Graul, Isabel; Wilharm, Arne; Klos, Kajetan; Hofmann, Gunther O.; Florian Gras, Marc

    2015-01-01

    Background: Volar locking plate fixation has become the gold standard in the treatment of unstable distal radius fractures. Juxta-articular screws should be placed as close as possible to the subchondral zone, in an optimized length to buttress the articular surface and address the contralateral cortical bone. On the other hand, intra-articular screw misplacements will promote osteoarthritis, while the penetration of the contralateral bone surface may result in tendon irritations and ruptures. The intraoperative control of fracture reduction and implant positioning is limited in the common postero-anterior and true lateral two-dimensional (2D)-fluoroscopic views. Therefore, additional 2D-fluoroscopic views in different projections and intraoperative three-dimensional (3D) fluoroscopy were recently reported. Nevertheless, their utility has issued controversies. Objectives: The following questions should be answered in this study; 1) Are the additional tangential view and the intraoperative 3D fluoroscopy useful in the clinical routine to detect persistent fracture dislocations and screw misplacements, to prevent revision surgery? 2) Which is the most dangerous plate hole for screw misplacement? Patients and Methods: A total of 48 patients (36 females and 13 males) with 49 unstable distal radius fractures (22 x 23 A; 2 x 23 B, and 25 x 23 C) were treated with a 2.4 mm variable angle LCP Two-Column volar distal radius plate (Synthes GmbH, Oberdorf, Switzerland) during a 10-month period. After final fixation, according to the manufactures' technique guide and control of implant placement in the two common perpendicular 2D-fluoroscopic images (postero-anterior and true lateral), an additional tangential view and intraoperative 3D fluoroscopic scan were performed to control the anatomic fracture reduction and screw placements. Intraoperative revision rates due to screw misplacements (intra-articular or overlength) were evaluated. Additionally, the number of surgeons, time and radiation-exposure, for each step of the operating procedure, were recorded. Results: In the standard 2D-fluoroscopic views (postero-anterior and true lateral projection), 22 screw misplacements of 232 inserted screws were not detected. Based on the additional tangential view, 12 screws were exchanged, followed by further 10 screws after performing the 3D fluoroscopic scan. The most lateral screw position had the highest risk for screw misplacement (accounting for 45.5% of all exchanged screws). The mean number of images for the tangential view was 3 ± 2.5 images. The mean surgical time was extended by 10.02 ± 3.82 minutes for the 3D fluoroscopic scan. An additional radiation exposure of 4.4 ± 4.5seconds, with a dose area product of 39.2 ± 14.5 cGy/cm2 were necessary for the tangential view and 54.4 ± 20.9 seconds with a dose area product of 2.1 ± 2.2 cGy/cm2, for the 3D fluoroscopic scan. Conclusions: We recommend the additional 2D-fluoroscopic tangential view for detection of screw misplacements caused by overlength, with penetration on the dorsal cortical surface of the distal radius, predominantly observed for the most lateral screw position. The use of intraoperative 3D fluoroscopy did not become accepted in our clinical routine, due to the technical demanding and time consuming procedure, with a limited image quality so far. PMID:26101762

  2. Long term results with the interlocking uncemented long stem in revision hip arthroplasty: a mean 15-year follow-up.

    PubMed

    Kamada, Tomomi; Imai, Hiroshi; Mashima, Naohiko; Takeba, Jun; Okumura, Hideo; Miura, Hiromasa

    2015-05-01

    Stem fixation is difficult to achieve in severe proximal bone loss in revision hip surgery. In this study, we sought to present the results of distally-locked stem with screws (HUCKESTEP HIP stem) in 21 revision hips with mean follow-up period of 15years. The preoperative mean Japanese Orthopaedic Association hip score had improved from 54 to 75 points. Further revisions were required for 2 stems, in one because of infection and the other because of screws fracture and subsidence. With removal of the stem for any reason as an end-point, the cumulative survival at 15years was 90.4%. While this study had small number, the use of this interlocking stem for revision hips with extensive proximal bone defects provided satisfactory 15-year clinical and radiographic results. PMID:25637474

  3. 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. PMID:15193078

  4. Lithium Lens Interlocks

    Microsoft Academic Search

    J. Krider

    1985-01-01

    The lithium lens in the antiproton source target vault is protected by an interlock system, which is located in relay racks R5 and R6 near the southwest corner of the Target Hall (building APO). The interlock system consists of crates of commercial signal conditioner and alarm modules built by Acromag, Inc and interlock Master Modules built by Fermilab: Twenty analog

  5. Alcohol ignition interlock programs.

    PubMed

    Beirness, D J; Marques, P R

    2004-09-01

    The alcohol ignition interlock is an in-vehicle DWI control device that prevents a car from starting until the operator provides a breath alcohol concentration (BAC) test below a set level, usually .02% (20 mg/dl) to .04% (40 mg/dl). The first interlock program was begun as a pilot test in California 18 years ago; today all but a few US states, and Canadian provinces have interlock enabling legislation. Sweden has recently implemented a nationwide interlock program. Other nations of the European Union and as well as several Australian states are testing it on a small scale or through pilot research. This article describes the interlock device and reviews the development and current status of interlock programs including their public safety benefit and the public practice impediments to more widespread adoption of these DWI control devices. Included in this review are (1) a discussion of the technological breakthroughs and certification standards that gave rise to the design features of equipment that is in widespread use today; (2) a commentary on the growing level of adoption of interlocks by governments despite the judicial and legislative practices that prevent more widespread use of them; (3) a brief overview of the extant literature documenting a high degree of interlock efficacy while installed, and the rapid loss of their preventative effect on repeat DWI once they are removed from the vehicles; (4) a discussion of the representativeness of subjects in the current research studies; (5) a discussion of research innovations, including motivational intervention efforts that may extend the controlling effect of the interlock, and data mining research that has uncovered ways to use the stored interlock data record of BAC tests in order to predict high risk drivers; and (6) a discussion of communication barriers and conceptual rigidities that may be preventing the alcohol ignition interlock from taking a more prominent role in the arsenal of tools used to control DWI. Whether interlock programs can help public policymakers achieve their expressed goals of substantially reducing the level of impaired driving will remain uncertain until procedural barriers and intransigent judiciary practices can be overcome that provide for more systematic routine use of interlock programs. Despite strong effectiveness evidence in all studies to date, the real potential of this technology to reduce the road toll cannot be estimated until they are more widely adopted. PMID:15276931

  6. Distributed Supervisory Protection Interlock System

    SciTech Connect

    Walz, H.V.; Agostini, R.C.; Barker, L.; Cherkassky, R.; Constant, T.; Matheson, R.

    1989-03-01

    The Distributed Supervisory Protection Interlock System, DSPI, is under development at the Stanford Linear Accelerator Center for requirements in the areas of personnel protection, beam containment and equipment protection interlocks. The DSPI system, distributed over the application site, consists of segments with microprocessor-based controller and I/O modules, local area networks for communication, and a global supervisor computer. Segments are implemented with commercially available controller and I/O modules arranged in local interlock clusters, and associated software. Segments provide local interlock data acquisition, processing and control. Local area networks provide the communication backbone between segments and a global supervisor processor. The supervisor processor monitors the overall system, reports detail status and provides human interfaces. Details of an R and D test system, which will implement the requirements for personnel protection of 4 typical linear accelerator sectors, will be described. 4 refs., 2 figs.

  7. 49 CFR 236.807 - Signal, interlocking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Signal, interlocking. 236.807 Section...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.807 Signal, interlocking. A roadway signal...

  8. 49 CFR 236.807 - Signal, interlocking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Signal, interlocking. 236.807 Section...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.807 Signal, interlocking. A roadway signal...

  9. 49 CFR 236.807 - Signal, interlocking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Signal, interlocking. 236.807 Section...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.807 Signal, interlocking. A roadway signal...

  10. 49 CFR 236.807 - Signal, interlocking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Signal, interlocking. 236.807 Section...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.807 Signal, interlocking. A roadway signal...

  11. 49 CFR 236.807 - Signal, interlocking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Signal, interlocking. 236.807 Section...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.807 Signal, interlocking. A roadway signal...

  12. 49 CFR 236.772 - Machine, interlocking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Transportation 4 2011-10-01 2011-10-01 false Machine, interlocking. 236.772 Section 236.772 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.772 Machine, interlocking. An assemblage of manually operated...

  13. 49 CFR 236.772 - Machine, interlocking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Transportation 4 2010-10-01 2010-10-01 false Machine, interlocking. 236.772 Section 236.772 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.772 Machine, interlocking. An assemblage of manually operated...

  14. A proposed methodology for the design and characterisation of concrete screw anchors

    Microsoft Academic Search

    G. A. Stuart; D. K. Harrison; B. M. Wood; M. Maclachlan

    2010-01-01

    In recent years the construction fixings industry has begun to look to the concrete screw anchor to alleviate lengthy installation\\u000a cycles and expansion issues, whilst introducing temporary fixing capability and suitability for use in cracked concrete. The\\u000a screw anchor, often used in heavy-duty structural applications, operates on a mechanical interlock principle by creating a\\u000a threaded cut in the substrate. Previous

  15. Anatomical and radiological study applied to distal radius surgery

    Microsoft Academic Search

    N. Gasse; D. Lepage; R. Pem; C. Bernard; J. M. Lerais; P. Garbuio; L. Obert

    Purpose  The purpose of this study was to determine, during anterior plating of the distal radius, the length of a screw above which\\u000a there is a risk for the extensor tendons and the optimal shape of an anterior plate. It was also to determine the projection\\u000a of the axis of the distal third of the radius on the distal articular surface

  16. Fractures of the bilateral distal radius and scaphoid: a case report

    Microsoft Academic Search

    Korhan Ozkan; Ender Ugutmen; Koray Unay; O?uz Poyanli; Melih Guven; Abdullah Eren

    2008-01-01

    INTRODUCTION: Bilateral fractures of the distal radius and scaphoid are extremely rare injuries. CASE PRESENTATION: A patient with bilateral comminuted, displaced distal fractures of the radius and bilateral fractures of the scaphoid was treated via internal fixation of the scaphoid fractures with Herbert screws and internal fixation of the distal radius fractures with locked volar plating. CONCLUSION: Rigid internal fixation

  17. Prevention of excessive medialisation of trochanteric fracture by a buttress screw: a novel method and finite element analysis.

    PubMed

    Mahaisavariya, Banchong; Chantarapanich, Nattapon; Riansuwan, Kongkhet; Sitthiseripratip, Kriskrai

    2014-09-01

    This paper proposes a novel method of using an antero-posterior buttress screw at the distal fragment just below the fracture site in conjunction with the sliding hip screw (SHS) to resist excessive femoral medialisation. A virtual assessment of the effectiveness of this new method was performed using the finite element analysis. The results indicate that the use ofa sliding hip screw (SHS) combined with a buttress screw can help resistfemoral medialisation better than using an SHS with no buttress screw. The von Mises equivalent stress (EQ ) was found to be in a safe range, which indicates increased integrity of the lateral wall with the addition of the buttress screw. PMID:25365905

  18. 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

  19. A Pitfall in Fixation of Distal Humeral Fractures with Pre-Contoured Locking Compression Plate

    PubMed Central

    Jayakumar, Prakash; Ring, David

    2015-01-01

    Anatomically precontoured locking plates are intended to facilitate the fixation of articular fractures and particularly those associated with osteoporosis. Fractures of the distal humerus are relatively uncommon injuries where operative intervention can be exceptionally challenging. The distal humeral trochlea provides a very narrow anatomical window through which to pass a fixed-angle locking screw, which must also avoid the olecranon, coronoid, and radial fossae. We describe 3 patients (ages 27, 49, and 73 years) with a bicolumnar fracture of the distal humerus where very short distal locking screws were used. Intra-articular screw placement was avoided but loss of fixation occurred in two patients and a third was treated with a prolonged period of immobilization. We postulate that fixed-angle screw trajectories may make it difficult for the surgeon to place screws of adequate length in this anatomically confined region, and may lead to insufficient distal fixation. Surgical tactics should include placement of as many screws as possible into the distal fragment, as long as possible and that each screw passes through a plate without necessarily locking in. PMID:26110181

  20. Comparison of Maxillary Molar Distalization with an Implant-Supported Distal Jet and a Traditional Tooth-Supported Distal Jet Appliance

    PubMed Central

    Cozzani, Mauro; Pasini, Marco; Zallio, Francesco; Ritucci, Robert; Mutinelli, Sabrina; Mazzotta, Laura; Giuca, Maria Rita; Piras, Vincenzo

    2014-01-01

    Aim. To investigate and compare the efficiency of two appliances for molar distalization: the bone-anchored distal screw (DS) and the traditional tooth-supported distal jet (DJ) for molar distalization and anchorage loss. Methods. Tests (18 subjects) were treated with a DS and controls (18 subjects) were treated with a DJ. Lateral cephalograms were obtained before and at the end of molar distalization and were analysed. Shapiro Wilk test, unpaired t-test, and Wilcoxon rank-sum test were applied according to values distribution. The ? level was fixed at 0.05. Results. Maxillary first molars were successfully distalized into a Class I relationship in all patients. The mean molar distalization and treatment time were similar in both groups. The DS group exhibited a spontaneous distalization (2.1 ± 0.9?mm) of the first premolar with control of anchorage loss, distal tipping, extrusion, and skeletal changes. Conclusions. The DS is an adequate compliance-free distalizing appliance that can be used safely for the correction of Class II malocclusions. In comparison to the traditional DJ, the DS enables not only a good rate of molar distalization, but also a spontaneous distalization of the first premolars. PMID:25018770

  1. The utility of the fluoroscopic skyline view during volar locking plate fixation of distal radius fractures.

    PubMed

    Vaiss, Lucile; Ichihara, Satoshi; Hendriks, Sarah; Taleb, Chihab; Liverneaux, Philippe; Facca, Sybille

    2014-11-01

    Background?Open reduction and internal fixation (ORIF) using a volar locking plate is a common method for treating displaced distal radius fractures. There is, however, the risk of extensor tendon rupture due to protrusion of the screw tips past the dorsal cortex, which cannot always be adequately seen on a lateral fluoroscopic view. We therefore wished to compare the sensitivity of an intraoperative fluoroscopic skyline view to a lateral fluorosocopic view in detecting past pointing of these screws. Material and Methods?Our series included 75 patients with an average age of 59 years who underwent volar locked plate fixation of a displaced distal radius fracture. Intraoperative anteroposterior (AP), lateral, and skyline fluoroscopic views were performed in each case. The number of screws that were seen to protrude past the dorsal cortex of the distal fracture fragment were recorded for both the lateral and skyline views. The number of screws that required exchange was also documented. Results?No screws were seen to protrude past the dorsal cortical bone on the lateral fluroscopic views. 15 of 300 screws (5%) were seen to protrude past the dorsal cortex by an average of 0.8?mm (range, 0.5 to 2 mm) and were exchanged for shorter screws in 11/75 patients. Conclusion?Our results demonstrate that the skyline is more sensitive than a lateral fluoroscopic view at demonstrating protrusion of the screws in the distal fracture fragment following volar locked plate fixation. Level of Evidence?IV. PMID:25364637

  2. Tangential views of the articular surface of the distal radius—aid to open reduction and internal fixation of fractures

    Microsoft Academic Search

    Deepak Kumar; L Breakwell; S. C Deshmukh; B. K Singh

    2001-01-01

    Open reduction and internal fixation of comminuted, displaced intra-articular or potentially unstable fractures of the distal radius with plate and screws has increasingly become a favoured treatment. Intra-operative assessment of fixation with the help of an image intensifier has always been difficult because of the anatomy of the distal radius. Imaging of the implants placed as distal as possible to

  3. Interlocking egg-crate type grid assembly

    DOEpatents

    Kast, Steven J. (Niskayuna, NY)

    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.

  4. 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.

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...false Electromechanical interlocking machine; locking between electrical and mechanical...340 Electromechanical interlocking machine; locking between electrical and mechanical... In electro-mechanical interlocking machine, locking between electric and...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...false Electromechanical interlocking machine; locking between electrical and mechanical...340 Electromechanical interlocking machine; locking between electrical and mechanical... In electro-mechanical interlocking machine, locking between electric and...

  7. 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

  8. 8. VIEW, LOOKING NORTH, OF INTERLOCKING MACHINE WITH ORIGINAL MODEL ...

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

    8. VIEW, LOOKING NORTH, OF INTERLOCKING MACHINE WITH ORIGINAL MODEL BOARD IN CENTER AND MODEL SEMAPHORE SIGNALS (AT TOP OF PHOTOGRAPH), THIRD FLOOR - South Station Tower No. 1 & Interlocking System, Dewey Square, Boston, Suffolk County, MA

  9. 9. VIEW, LOOKING SOUTH, OF INTERLOCKING MACHINE, WITH ORIGINAL MODEL ...

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

    9. VIEW, LOOKING SOUTH, OF INTERLOCKING MACHINE, WITH ORIGINAL MODEL BOARD IN CENTER, NEW MODEL BOARD AT LEFT AND MODEL SEMAPHORES AT TOP OF PHOTOGRAPH, THIRD FLOOR - South Station Tower No. 1 & Interlocking System, Dewey Square, Boston, Suffolk County, MA

  10. 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.

  11. Management of distal humeral coronal shear fractures.

    PubMed

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

    2015-05-16

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

  12. Distal splenorenal shunt

    MedlinePLUS

    ... splenic venous shunt; Warren shunt; Cirrhosis - distal splenorenal; Liver failure - distal splenorenal ... the intestine, spleen, pancreas, and gallbladder to the liver. When blood flow is blocked, the pressure in ...

  13. Distal Convoluted Tubule

    PubMed Central

    Ellison, David H.

    2014-01-01

    The distal convoluted tubule is the nephron segment that lies immediately downstream of the macula densa. Although short in length, the distal convoluted tubule plays a critical role in sodium, potassium, and divalent cation homeostasis. Recent genetic and physiologic studies have greatly expanded our understanding of how the distal convoluted tubule regulates these processes at the molecular level. This article provides an update on the distal convoluted tubule, highlighting concepts and pathophysiology relevant to clinical practice. PMID:24855283

  14. The Screw-worm. 

    E-print Network

    Francis, M. (Mark)

    1890-01-01

    TEXAS AGRICULTURAL EXP II,HIMEXT Srl'ATION. BULLETIN No. 12, ~*fZkRP ** SEPTEMBER, 1890. .$, y~, 'TWORM. AGRICULTURAL' AND MECHANICAL COLLEGE OF TEXAS. All Bulletins of this Station are issued free. Any one interested... to Director. ,nt Agriculturist. . . naala~ant in Chemistrv. . . LVL~L~OI' . . Assists . . Assista A ..-:-A- TEXAS AGYLICULTUliAL EXYEliIMEXT STATION. THE SCREW-WORM. - . . . .. .-. -- M. FRANCIS, D. V. M. ~ - - In the First Annual Report...

  15. 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.

  16. Mechanically interlocked single-wall carbon nanotubes.

    PubMed

    de Juan, Alberto; Pouillon, Yann; Ruiz-González, Luisa; Torres-Pardo, Almudena; Casado, Santiago; Martín, Nazario; Rubio, Ángel; Pérez, Emilio M

    2014-05-19

    Extensive research has been devoted to the chemical manipulation of carbon nanotubes. The attachment of molecular fragments through covalent-bond formation produces kinetically stable products, but implies the saturation of some of the C-C double bonds of the nanotubes. Supramolecular modification maintains the structure of the SWNTs but yields labile species. Herein, we present a strategy for the synthesis of mechanically interlocked derivatives of SWNTs (MINTs). In the key rotaxane-forming step, we employed macrocycle precursors equipped with two ?-extended tetrathiafulvalene SWNT recognition units and terminated with bisalkenes that were closed around the nanotubes through ring-closing metathesis (RCM). The mechanically interlocked nature of the derivatives was probed by analytical, spectroscopic, and microscopic techniques, as well as by appropriate control experiments. Individual macrocycles were observed by HR?STEM to circumscribe the nanotubes. PMID:24729452

  17. 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%. PMID:9702635

  18. Distal median nerve dysfunction

    MedlinePLUS

    ... type of distal median nerve dysfunction is carpal tunnel syndrome . ... repetitive movements increase the chance of developing carpal tunnel entrapment. Conditions that affect connective tissue or cause ...

  19. 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.

  20. 21 CFR 876.4590 - Interlocking urethral sound.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4590 Interlocking urethral sound. (a) Identification. An...

  1. 21 CFR 876.4590 - Interlocking urethral sound.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4590 Interlocking urethral sound. (a) Identification. An...

  2. 21 CFR 876.4590 - Interlocking urethral sound.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4590 Interlocking urethral sound. (a) Identification. An...

  3. 21 CFR 876.4590 - Interlocking urethral sound.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4590 Interlocking urethral sound. (a) Identification. An...

  4. 21 CFR 876.4590 - Interlocking urethral sound.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4590 Interlocking urethral sound. (a) Identification. An...

  5. Les amyotrophies spinales distales

    Microsoft Academic Search

    P. Devic; P. Petiot

    2011-01-01

    IntroductionDistal hereditary motor neuropathy (dHMN), also known as spinal muscular atrophy, represents a group of clinically and genetically heterogeneous diseases caused by degenerations of spinal motor neurons and leading to distal muscle weakness and wasting. Nerve conduction studies reveal a pure motor axonopathy and needle examination shows chronic denervation.

  6. Efficiency of a pendulum appliance for molar distalization related to second and third molar eruption stage

    Microsoft Academic Search

    Gero S. M Kinzinger; Ulrike B Fritz; Franz-Günter Sander; Peter R Diedrich

    2004-01-01

    A modified pendulum appliance, including a distal screw and special preactivated pendulum springs (built-in straightening activation and toe-in bending), was used for bilateral maxillary molar distalization in 36 adolescent patients in various stages of the molar dentition. The patients were divided into 3 groups (PG 1-3) according to the stage of eruption of their second and third molars. In PG

  7. 49 CFR 1242.58 - Operating signals and interlockers, operating drawbridges, highway crossing protection (accounts...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...signals, interlockers, drawbridges and highway crossings are...

  8. 49 CFR 1242.58 - Operating signals and interlockers, operating drawbridges, highway crossing protection (accounts...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...signals, interlockers, drawbridges and highway crossings are...

  9. 49 CFR 1242.58 - Operating signals and interlockers, operating drawbridges, highway crossing protection (accounts...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...signals, interlockers, drawbridges and highway crossings are...

  10. 49 CFR 1242.58 - Operating signals and interlockers, operating drawbridges, highway crossing protection (accounts...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...signals, interlockers, drawbridges and highway crossings are...

  11. 49 CFR 1242.58 - Operating signals and interlockers, operating drawbridges, highway crossing protection (accounts...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...interlockers, operating drawbridges, highway crossing protection (accounts XX-51-59...signals, interlockers, drawbridges and highway crossings are...

  12. 49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...interlocking machine; locking between electrical and mechanical levers. 236.340 Section 236.340...interlocking machine; locking between electrical and mechanical levers. In electro-mechanical interlocking machine, locking between...

  13. 49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...interlocking machine; locking between electrical and mechanical levers. 236.340 Section 236.340...interlocking machine; locking between electrical and mechanical levers. In electro-mechanical interlocking machine, locking between...

  14. 49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...interlocking machine; locking between electrical and mechanical levers. 236.340 Section 236.340...interlocking machine; locking between electrical and mechanical levers. In electro-mechanical interlocking machine, locking between...

  15. 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

  16. An Innovative Universal Screw Removal Instrument

    PubMed Central

    Elmada?, Mehmet; Uzer, Gökçer; Acar, Mehmet Ali

    2015-01-01

    Objective To present the clinical benefits of an instrument designed to facilitate removal of polyaxial screws during revision surgery. Methods All polyaxial screws can be removed without additional materials or a large amount of debridement using our newly designed instrument. Forty-two screws were removed from five patients without any complications using this instrument. Results We removed the cap screws and rods from the 42 polyaxial screws in five patients and made them monoaxial using the new screw removal apparatus. The screws and rods were removed quickly in a minimally invasive way with no complications. No damage to the pedicle or surrounding soft tissue occurred during screw removal. No neurogenic changes developed during revision surgery after changing the screws. Conclusion This newly designed screw removal instrument was used safely and effectively to remove all polyaxial and monoaxial pedicle screws. PMID:25883660

  17. Overlapping intramedullary nailing after failed minimally invasive locked plating for osteoporotic distal femur fractures - Report of 2 cases.

    PubMed

    Yoo, Je-Hyun; Kim, Seok-Woo; Kwak, Yoon-Hae; Kim, Hyung-Jun

    2015-06-01

    Minimally invasive plate osteosynthesis (MIPO) using a locking plate has been widely used for distal femur fractures in the elderly with osteoporosis and yielded favourable results. However, implant failure and subsequent periplate fracture have still occurred owing to the controversy of concepts regarding locked plating. The treatment after failed MIPO in elderly patients is very challenging and has been not yet addressed definitely in the literature, although several options can be considered. We report the successful outcomes of two cases treated with overlapping intramedullary (IM) nailing for implant failure and periplate fracture after MIPO for osteoporotic distal femur fracture, along with simple tips of distal interlocking of IM nail. PMID:25624271

  18. 14. General oblique view of Shell Interlocking Tower, north and ...

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

    14. General oblique view of Shell Interlocking Tower, north and west facades, showing over head catenary tower and bridge at right. - 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

  19. 4. North elevation of Shell Interlocking Tower showing structure built ...

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

    4. North elevation of Shell Interlocking Tower showing structure built into slope of railroad right-of-way. - 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

  20. 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

  1. 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

  2. 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

  3. 12 CFR 303.249 - Management official interlocks.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (1) A description of the proposed interlock; (2) A statement of reason as to why the interlock will not result in a monopoly or a substantial lessening of competition; and (3) If the applicant is seeking an exemption set forth in §...

  4. The principle of topological interlocking in extraterrestrial construction

    Microsoft Academic Search

    A. V. Dyskin; Y. Estrin; E. Pasternak; H. C. Khor; A. J. Kanel-Belov

    2005-01-01

    Applications of a newly established principle of topological interlocking to different types of extraterrestrial construction are considered. Topological interlocking arises when elements of special shapes (usually convex or nearly convex, such that no stress concentration develops) are arranged in such a way that neither of them can be removed from the assembly without disturbing the neighbouring elements. Two types of

  5. Biodegradable interlocking nails for fracture fixation.

    PubMed

    van der Elst, M; Bramer, J A; Klein, C P; de Lange, E S; Patka, P; Haarman, H J

    1998-12-01

    Serious problems such as stress shielding, allergic reactions, and corrosion are associated with the use of metallic fracture fixation devices in fractured long bones. Metal implants often are removed during a second retrieval operation after fracture healing has completed. A biocompatible implant that degrades slowly during implantation would obviate the need for a second operation and save the patient from considerable physical, psychologic, and financial discomfort. The biodegradable implant must provide the fractured limb sufficient support for a certain time, allowing early loading. A gradual transfer of load from the biodegradable implant to the bone would result in a better product of bone healing and avoid stress shielding. In an animal model using adult sheep, two types of biodegradable polymer interlocking nails were tested in comparison with a stainless steel interlocking nail. Fracture healing, mechanical properties of the bones, degradation behavior in vivo and in vitro, and tissue response were monitored during a 2 1/2-year followup study. To detect shifts in acid base relations caused by the release of acid compounds, pH measurements were performed. Fracture healing was unimpaired, and the mechanical test results of all three groups were excellent. Histologic analysis showed a mild inflammatory response, but no pH shifts were observed. The results of this study justify additional research on these promising materials. PMID:9917717

  6. Distal movement of mandibular molars in adult patients with the skeletal anchorage system

    Microsoft Academic Search

    Junji Sugawara; Takayoshi Daimaruya; Mikako Umemori; Hiroshi Nagasaka; Ichiro Takahashi; Hiroshi Kawamura; Hideo Mitani

    2004-01-01

    The skeletal anchorage system (SAS) consists of titanium anchor plates and monocortical screws that are temporarily placed in either the maxilla or the mandible, or in both, as absolute orthodontic anchorage units. Distalization of the molars has been one of the most difficult biomechanical problems in traditional orthodontics, particularly in adults and in the mandible. However, it has now become

  7. 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.

  8. Construction and Biomechanical Properties of PolyAxial Self-Locking Anatomical Plate Based on the Geometry of Distal Tibia

    PubMed Central

    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. PMID:25025051

  9. 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.

  10. Maisonneuve fracture with an associated distal fibular fracture. A case report.

    PubMed

    Slawski, D P; West, C

    1995-08-01

    A 46-year-old woman had a severe torsional injury to her left leg. Admission radiographs showed a proximal Maisonneuve-type fibular fracture with an associated distal fibular fracture at the level of the distal tibiofibular syndesmosis. A complete syndesmotic disruption, proximal and distal to the distal fibular fracture, was verified at surgical exploration as was a complete deltoid ligament tear. Management consisted of internal fixation of the distal fibular fracture and placement of a syndesmotic screw. At 1-year followup, the patient reported normal ankle function. This case represents an unusual, and perhaps previously undescribed, variant of the so-called Maisonneuve fracture. The need for careful evaluation of the entire leg in torsional injuries of the ankle is underscored by the injury presented. PMID:7671478

  11. Edgewood Interlocking Tower. Edgewood, Hareford Co., MD. Sec. 1201, MP ...

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

    Edgewood Interlocking Tower. Edgewood, Hareford Co., MD. Sec. 1201, MP 75.50. - Northeast Railroad Corridor, Amtrak route between District of Columbia/Maryland state line & Maryland/Delaware state line, Baltimore, Independent City, MD

  12. Perryville Interlocking Tower. Perryville, Cecil Co., MD. Sec. 1201, MP ...

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

    Perryville Interlocking Tower. Perryville, Cecil Co., MD. Sec. 1201, MP 59.10. - Northeast Railroad Corridor, Amtrak route between District of Columbia/Maryland state line & Maryland/Delaware state line, Baltimore, Independent City, MD

  13. BOWIE INTERLOCKING TOWER AND PASSENGER STATION. BOWIE, PRINCE GEORGES CO., ...

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

    BOWIE INTERLOCKING TOWER AND PASSENGER STATION. BOWIE, PRINCE GEORGES CO., MD. Sec. 1201, MP 120.50. - Northeast Railroad Corridor, Amtrak route between District of Columbia/Maryland state line & Maryland/Delaware state line, Baltimore, Independent City, MD

  14. 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

  15. Union Junction Interlocking Tower. Baltimore, Baltimore City, MD. Sec. 1201, ...

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

    Union Junction Interlocking Tower. Baltimore, Baltimore City, MD. Sec. 1201, MP 95.49. - Northeast Railroad Corridor, Amtrak route between District of Columbia/Maryland state line & Maryland/Delaware state line, Baltimore, Independent City, MD

  16. 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

  17. 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... Section 212.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MANAGEMENT OFFICIAL INTERLOCKS...A Federal Home Loan Bank or any other...

  18. 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... Section 212.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MANAGEMENT OFFICIAL INTERLOCKS...A Federal Home Loan Bank or any other...

  19. 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... Section 212.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MANAGEMENT OFFICIAL INTERLOCKS...A Federal Home Loan Bank or any other...

  20. 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... Section 212.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MANAGEMENT OFFICIAL INTERLOCKS...A Federal Home Loan Bank or any other...

  1. 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... Section 212.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MANAGEMENT OFFICIAL INTERLOCKS...A Federal Home Loan Bank or any other...

  2. 13. INTERIOR, OPERATOR'S HOUSE, ELECTROMECHANICAL INTERLOCKING MACHINE New York, ...

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

    13. INTERIOR, OPERATOR'S HOUSE, ELECTRO-MECHANICAL INTERLOCKING MACHINE - New York, New Haven & Hartford Railroad, Mystic River Bridge, Spanning Mystic River between Groton & Stonington, Groton, New London County, CT

  3. 12. DETAIL VIEW OF INTERLOCKING RAIL CONNECTION AT FREE END ...

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

    12. DETAIL VIEW OF INTERLOCKING RAIL CONNECTION AT FREE END OF MOVING LEAF - Seddon Island Scherzer Rolling Lift Bridge, Spanning Garrison Channel from Tampa to Sedden Island, Tampa, Hillsborough County, FL

  4. 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

  5. Perforation of the Third Extensor Compartment by the Drill Bit During Palmar Plating of the Distal Radius

    Microsoft Academic Search

    W. PICHLER; W. GRECHENIG; H. CLEMENT; G. WINDISCH; N. P. TESCH

    2009-01-01

    The frequency of penetration into the third extensor compartment when drilling the distal screw holes was assessed for four different palmar distal radius plates in 160 cadaver forearms. Penetration into this compartment occurred in 43%. Different plates had different penetration rates: 3.5 LCP four-hole locking T-plate: 20%, 3.5 LCP three-hole locking plate: 42.5%, 2.4 palmar LCP standard plate and the

  6. Expandable insert serves as screw anchor

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Expandable self-locking adapter secures components to panels having one accessible side. Mounting holes in the panels may not be threaded to accommodate screws, therefore, the adapter contains a female thread that will mate a mounting screw.

  7. Limiting the dimension of a screw-access hole with an interim screw-retained prosthesis.

    PubMed

    Wadhwani, Chandur; Chung, Kwok-Hung

    2015-06-01

    Fabricating an interim screw-retained prosthesis often involves obliteration of the abutment screw access site, which later must be exposed. This frequently results in excessive preparation of the screw access site with poor esthetics and a weaker restoration. The technique described expedites the process by locating the access site and limits the size of the screw access hole preparation. PMID:25858223

  8. Osteosynthesis of distal radius fractures with the Micronail ®

    Microsoft Academic Search

    Raoul van VugtRon; Ron W. P. M. Geerts; Andries J. Werre

    2010-01-01

    Introduction  The Micronail® is a minimally invasive intramedullar titanium locking screw fixation for two-part dislocated extra-articular fractures and\\u000a average displaced intra-articular fractures.\\u000a \\u000a \\u000a \\u000a \\u000a Patients and methods  In a retrospective study we analyzed the outcome of 20 distal radius fractures in 18 patients (17 female, mean age 78 years),\\u000a which were treated by Micronail®. Average follow-up time was 4 months. We describe the operative technique. All

  9. Screw symmetry in columnar crystals

    E-print Network

    A. Mughal

    2013-06-12

    We show that the optimal packing of hard spheres in an infinitely long cylinder yields structures characterised by a screw symmetry. Each packing can be assembled by stacking a basic unit cell ad infinitum along the length of the cylinder with each subsequent unit cell rotated by the same twist angle with respect to the previous one. In this paper we quantitatively describe the nature of this screw operation for all such packings in the range 1 <= D/d <= 2.715 and also briefly discuss their helicity.

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

    PubMed Central

    Uzun, Metin; Kara, Adnan; Ada?, Müjdat; Karslio?lu, Bülent; Bülbül, Murat; Beksaç, Burak

    2014-01-01

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

  11. An eigenproblem approach to classical screw theory

    Microsoft Academic Search

    Sandipan Bandyopadhyay; Ashitava Ghosal

    2009-01-01

    This paper presents a novel algebraic formulation of the central problem of screw theory, namely the determination of the principal screws of a given system. Using the algebra of dual numbers, it shows that the principal screws can be determined via the solution of a generalised eigenproblem of two real, symmetric matrices. This approach allows the study of the principal

  12. [The pendulis appliance: a palatal miniscrew supported molar distalization device].

    PubMed

    Nappée-Miévilly, Magali; Nappée, François-Joseph; Kerbrat, Jean-Baptiste; Goudot, Patrick

    2014-09-01

    The maxillary molar distalization is a valuable therapeutic option in some clinical cases. Its biomechanics is challenging and difficult to obtain. Historically, various devices have been described offering successful solutions to this problem such as the Hilgers Pendulum Appliance (1992) and variants linked to mini screws which recently have shown interesting clinical potential. This article presents a new Pendulum variant using a miniscrew, the "pendulis". It follows the original concept (titanium-molybdenum alloy distalization springs and polymethyl-methacrylate pellet) but dental support is replaced by a single palatal miniscrew (median adults, para-median in children) to which the device is fixed by means of a metal welded cap easily positioned and removable by the practitioner. This allows for better control of the oral hygiene and completely controlled extraoral activation. Fabrication steps are described and instruction of use is illustrated with clinical documentation. PMID:25158749

  13. A screw propelling capsule robot

    Microsoft Academic Search

    Huajin Liang; Yisheng Guan; Zhiguang Xiao; Chao Hu; Zhiyong Liu

    2011-01-01

    This paper presents a novel approach to active capsule robot, traversing in a tubular and compliant environment containing solid-liquid mixture. One of the application fields is active capsule endoscopy intended to navigate inside the gastrointestinal tract for diagnosis and therapy. This robot is driven by a screw impeller, which converts rotation to axial motion in two ways: one is through

  14. Air-Lubricated Lead Screw

    NASA Technical Reports Server (NTRS)

    Perkins, G. S.

    1983-01-01

    Air lubricated lead screw and nut carefully machined to have closely matched closely fitting threads. Compressed air injected into two plenums encircle nut and flow through orifices to lubricate mating threads. Originally developed to position precisely interferometer retroreflector for airborne measurement of solar infrared radiation, device now has positioning accuracy of 0.25 micron.

  15. Coracoid fracture combined with distal clavicle fracture without coracoclavicular ligament rupture: A case report

    PubMed Central

    Allagui, M.; Koubaa, M.; Aloui, I.; Zrig, M.; Hamdi, M.F.; Abid, A.

    2013-01-01

    Distal clavicle fracture accompanied by coracoid process one is a rare injury. Surgical and/or conservative treatments are proposed. We report the case of a 49-year-old woman presenting a distal clavicle fracture associated with a coracoid process one due to a fall on the left shoulder. Both injuries are treated surgically. Per operatively, and through an anterior “strap” approach, the coracoclavicular ligament was seen intact. The distal clavicle fracture was fixed with K-wires and cerclage and the coracoid process was secured by a screw. Active-assisted rehabilitation of the shoulder was initiated 3 weeks after surgery. At the last follow-up of twelve months, the patient had painless full shoulder functions and X-rays show bony union. Early recovery to normal life is possible with surgical treatment in patients with distal clavicle fracture combined with coracoid fracture.

  16. Retrieval of broken iliosacral screws: The power of a push screw.

    PubMed

    El Dafrawy, Mostafa H; Osgood, Greg M

    2015-07-01

    Percutaneous iliosacral screw fixation is a common technique that is widely used for unstable posterior pelvic ring disruptions. Complications of posterior percutaneous iliosacral screw fixation include implant malpositioning and hardware failure. Removal of iliosacral screws in broken or symptomatic hardware is sometimes necessary. To our knowledge, there are few reports addressing pelvic implant removal, and most of those report on anterior pelvic implants and symphyseal plates. There are no reports describing techniques for retrieval of broken iliosacral screws. We present two cases involving removal of broken sacroiliac screws, review the literature regarding iliosacral implant extraction, and identify important aspects of safe extraction of iliosacral screws and the potential complications associated with their retrieval. We further describe a novel and powerful technique to facilitate percutaneous removal of broken screw fragments, using a "push screw" to drive a broken screw fragment from a position buried in bone. PMID:25986663

  17. A Case of Pedicle Screw Loosening Treated by Modified Transpedicular Screw Augmentation with Polymethylmethacrylate

    PubMed Central

    Kang, Suk-Hyung; Kim, Kyoung-Tae; Park, Seung Won

    2011-01-01

    We report a case of pedicle screw loosening treated by modified transpedicular screw augmentation technique using polymethylmethacrylate (PMMA), which used the anchoring effect of hardened PMMA. A 56-year-old man who had an L3/4/5 fusion operation 3 years ago complained of continuous low back pain after this operation. The computerized tomography showed a radiolucent halo around the pedicle screw at L5. We augmented the L5 pedicle screw with modified pedicle screw augmentation technique using PMMA and performed an L3/4/5 pedicle screw fixation without hook or operation field extension. This modified technique is a kind of transpedicular stiffness augmentation using PMMA for the dead space around the loosed screw. After filling the dead space with 1-2 cc of PMMA, we inserted a small screw. Once the PMMA hardened, we removed the small screw and inserted a thicker screw along the existing screw threading to improve the pedicle screws' pullout strength. At 10 months' follow-up, x-ray showed strong fusion of L3/4/5. The visual analogue scale (VAS) of his back pain was improved from 9 to 5. This modified transpedicular screw augmentation with PMMA using anchoring effect is a simple and effective surgical technique for pedicle screw loosening. However, clinical analyses of long-term follow-up and biomechanical studies are needed. PMID:21494370

  18. A Comparison of Functional Outcomes After Metallic and Bioabsorbable Interference Screw Fixations in Arthroscopic ACL Reconstructions

    PubMed Central

    Rai, Deepak K; Kannampilly, Antony J

    2014-01-01

    Introduction: Anterior Cruciate Ligament (ACL) is as one of the most frequently injured ligaments in the modern contact sports scenario. Graft fixations can be achieved during anterior cruciate ligament (ACL) reconstructions by using either bioabsorbable screws or metal screws. The objective of this study was to compare the functional outcomes after bioabsorbable and metallic interference screw fixations in arthroscopic anterior cruciate ligament reconstructions done by using hamstring grafts. Materials and Methods: This was a prospective, randomized study. Patients in Group 1 received bioabsorbable interference screws and patients in Group 2 received metallic interference screws. Arthroscopic assisted, anterior cruciate ligament reconstructions with the use of hamstring grafts which were fixed proximally with endobuttons and distally with bioabsorbable or metallic interference screws, were undertaken. Progress in functional outcomes was assessed by using Mann Whitney U- test. Functional outcomes in the two groups were compared by using independent t-test. Observation and Results: In each group, there were statistically significant improvements in functional outcomes over successive follow-ups, which were seen on basis on Mann-Whitney U-test. The comparison of functional outcomes between the two groups, done by using independent t-test, showed no statistically significant differences between the two groups at 3 months, 6 months and 1 year of follow-up. p-value <0.05 was considered to be significant in our study. Conclusion: In our prospective study of comparison of functional outcomes between bioabsorbable and metallic interference screws in arthroscopic anterior cruciate ligament reconstuctions, which were evaluated by using Tegner activity scale and Lysholm knee scoring scale for a period of 1 year, no statistically significant difference was found. However, further authentication is required by doing long term studies. PMID:24959468

  19. Unusually high sound absorption in topological interlocking materials

    NASA Astrophysics Data System (ADS)

    Estrin, Yuri; Molotnikov, Andrey; Carlesso, Mateus

    2015-04-01

    Topological interlocking materials are a new class of architectured materials, which have a range of unusual mechanical and acoustic properties. We present a novel approach for combating noise pollution based on the concept of topological interlocking. Specifically, we propose to segment monolithic plates into an assembly of topologically interlocked building blocks and show experimentally that this leads to a spectacular increase of the sound absorption coefficient over that in the original material, as exemplified by ceramics. Measurements of the airflow resistance confirmed the primary role of segmentation in enhancing sound absorption capability of the material in the audible frequency range. The absorption coefficient was further boosted by design of the material itself. The new material design proposed poses some interesting challenges to theory of sound wave propagation in heterogeneous media.

  20. 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

  1. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...false Movable bridge, interlocking of signal appliances with bridge devices. 236...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...312 Movable bridge, interlocking of signal appliances with bridge devices....

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...false Movable bridge, interlocking of signal appliances with bridge devices. 236...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...312 Movable bridge, interlocking of signal appliances with bridge devices....

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...false Movable bridge, interlocking of signal appliances with bridge devices. 236...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...312 Movable bridge, interlocking of signal appliances with bridge devices....

  4. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...false Movable bridge, interlocking of signal appliances with bridge devices. 236...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...312 Movable bridge, interlocking of signal appliances with bridge devices....

  5. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...false Movable bridge, interlocking of signal appliances with bridge devices. 236...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...312 Movable bridge, interlocking of signal appliances with bridge devices....

  6. 46 CFR 111.91-1 - Power, control, and interlock circuits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Elevators and Dumbwaiters § 111.91-1 Power, control, and interlock...Each electric power, control, and interlock circuit of an elevator or dumbwaiter must meet ASME A17.1 (incorporated by...

  7. 46 CFR 111.91-1 - Power, control, and interlock circuits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Elevators and Dumbwaiters § 111.91-1 Power, control, and interlock...Each electric power, control, and interlock circuit of an elevator or dumbwaiter must meet ASME A17.1 (incorporated by...

  8. 46 CFR 111.91-1 - Power, control, and interlock circuits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Elevators and Dumbwaiters § 111.91-1 Power, control, and interlock...Each electric power, control, and interlock circuit of an elevator or dumbwaiter must meet ASME A17.1 (incorporated by...

  9. 46 CFR 111.91-1 - Power, control, and interlock circuits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Elevators and Dumbwaiters § 111.91-1 Power, control, and interlock...Each electric power, control, and interlock circuit of an elevator or dumbwaiter must meet ASME A17.1 (incorporated by...

  10. 46 CFR 111.91-1 - Power, control, and interlock circuits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Elevators and Dumbwaiters § 111.91-1 Power, control, and interlock...Each electric power, control, and interlock circuit of an elevator or dumbwaiter must meet ASME A17.1 (incorporated by...

  11. 46 CFR 111.70-7 - Remote control, interlock, and indicator circuits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...device is not more than 300 percent of the current-carrying capacity of the control, interlock, or indicator circuit...setting of not more than 300 percent of the current-carrying capacity of the control, electrical interlock, or...

  12. Metatarsalgia: distal metatarsal osteotomies.

    PubMed

    Schuh, Reinhard; Trnka, Hans Joerg

    2011-12-01

    Metatarsalgia is a common pathologic entity. It refers to pain at the MTP joints. Pain in the foot unrelated to the MTP joints (such as Morton’s neuroma) must be distinguished from those disorders, which lead to abnormal pressure distribution, reactive calluses, and pain. Initial treatment options for metatarsalgia include modifications of shoe wear, metatarsal pads, and custom-made orthoses. If conservative treatment fails, operative reconstructive procedures in terms of metatarsal osteotomies should be considered. Lesser metatarsal osteotomy is an effective and well-accepted method for the management of metatarsalgia. The main purpose of these osteotomies is to decrease prominence of the symptomatic metatarsal head. The distal metatarsal oblique osteotomy (Weil osteotomy) with its modification represents the best evaluated distal metatarsal osteotomy in terms of outcome studies and biomechanical analysis. The role of the Weil osteotomy in metatarsalgia owing to a subluxed or dislocated MTP joint is to bring the metatarsal head proximal to the callus and to provide axial decompression of the toe to correct the deformity contributing to metatarsalgia. PMID:22118231

  13. 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.

  14. 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.

  15. Biomechanical evaluation of a medial knee reconstruction with comparison of bioabsorbable interference screw constructs and optimization with a cortical button.

    PubMed

    Wijdicks, Coen A; Brand, Emily J; Nuckley, David J; Johansen, Steinar; LaPrade, Robert F; Engebretsen, Lars

    2010-11-01

    Current fixation techniques in medial knee reconstructions predominantly utilize interference screws alone for soft tissue graft fixation. The use of concurrent fixation techniques as part of a hybrid fixation technique has also been suggested to strengthen soft tissue fixation, although these hybrid fixation techniques have not been biomechanically validated. The purpose was to biomechanically evaluate two distal tibial superficial MCL graft fixation techniques that consisted of an interference screw alone and in combination with a cortical button. Furthermore, the aim was to compare interference screws of different constructs. Twenty-four porcine tibias (average bone mineral density of 1.3 ± 0.2 g/cm(2); range, 1.0-1.6 g/cm(2), measured by DEXA scan) were divided into 4 groups of six specimens each. Group Ia consisted of a 7 × 23-mm poly-L-lactide (PLLA) interference screw. Group Ib utilized a PLLA interference screw in combination with a cortical button. Group IIa consisted of a 7 × 23-mm composite 70% poly(L-lactide-co-D, L-lactide) and 30% biphasic calcium phosphate (BCP) interference screw. Group IIb also utilized a composite interference screw in combination with a cortical button. The specimens were biomechanically tested with cyclic (500 cycles, 50-250 N, 1 Hz) and load-to-failure (20 mm/min) parameters. During cyclic loading, a significant increase in stiffness was seen for the PLLA hybrid 29.6 (±6.9) N/mm fixation compared to the PLLA screw-only 21.2 (±3.8) N/mm group (P < 0.05). Failure loads were 407.8 (±77.9) N for the composite screw, 445 (±72.2) N for the PLLA screw-only, 473.9 (±69.6) N for the composite hybrid fixation, and 511.0 (±78.5) N for the PLLA hybrid fixation. The PLLA screw alone was found to provide adequate fixation for a superficial MCL reconstruction, and the use of a cortical suture button combined with the PLLA screw resulted in a stiffer fixation during cyclic loading. The current reconstruction superficial MCL graft fixation technique utilizing a PLLA interference screw alone serves as an adequate recreation of the native tibial superficial MCL strength. In addition, a hybrid fixation with a cortical button which lends additional cyclic stiffness to its fixation would be advisable for use in suboptimal fixation cases. PMID:20563561

  16. Complex fractures of the distal radius treated with angular stability plates

    Microsoft Academic Search

    Marco Frattini; Giovanni Soncini; Maurizio Corradi; Bruno Panno; Silvio Tocco; Francesco Pogliacomi

    2009-01-01

    Complex fractures of the distal radius are articular lesions and comminuted at the level of the epiphysis and metaphysis.\\u000a Their treatment is difficult and in most cases surgical. Of all the different osteosynthesis methods available, internal fixation\\u000a with plate and screws is the most commonly used. In particular, angular stability plates are superior in terms of rigidity\\u000a and stability to

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

    Microsoft Academic Search

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

    2001-01-01

    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

  18. Assessment of different screw augmentation techniques and screw designs in osteoporotic spines

    PubMed Central

    Chavanne, A.; Spitaler, R.; Kropik, K.; Aigner, N.; Ogon, M.; Redl, H.

    2008-01-01

    This is an experimental study on human cadaver spines. The objective of this study is to compare the pullout forces between three screw augmentation methods and two different screw designs. Surgical interventions of patients with osteoporosis increase following the epidemiological development. Biomechanically the pedicle provides the strongest screw fixation in healthy bone, whereas in osteoporosis all areas of the vertebra are affected by the disease. This explains the high screw failure rates in those patients. Therefore PMMA augmentation of screws is often mandatory. This study involved investigation of the pullout forces of augmented transpedicular screws in five human lumbar spines (L1–L4). Each spine was treated with four different methods: non-augmented unperforated (solid) screw, perforated screw with vertebroplasty augmentation, solid screw with vertebroplasty augmentation and solid screw with balloon kyphoplasty augmentation. Screws were augmented with Polymethylmethacrylate (PMMA). The pullout forces were measured for each treatment with an Instron testing device. The bone mineral density was measured for each vertebra with Micro-CT. The statistical analysis was performed with a two-sided independent student t test. Forty screws (10 per group and level) were inserted. The vertebroplasty-augmented screws showed a significant higher pullout force (mean 918.5 N, P = 0.001) than control (mean 51 N), the balloon kyphoplasty group did not improve the pullout force significantly (mean 781 N, P > 0.05). However, leakage occurred in some cases treated with perforated screws. All spines showed osteoporosis on Micro-CT. Vertebroplasty-augmented screws, augmentation of perforated screws and balloon kyphoplasty augmented screws show higher pullout resistance than non-augmented screws. Significant higher pullout forces were only reached in the vertebroplasty augmented vertebra. The perforated screw design led to epidural leakage due to the position of the perforation in the screw. The position of the most proximal perforation is critical, depending on screw design and proper insertion depth. Nevertheless, using a properly designed perforated screw will facilitate augmentation and instrumentation in osteoporotic spines. PMID:18781342

  19. 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

  20. 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.

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

    NASA Astrophysics Data System (ADS)

    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 I/O 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.

  2. Prompting Widespread, Durable Service Quality via Interlocking Contingencies.

    ERIC Educational Resources Information Center

    Sulzer-Azaroff, Beth; Pollack, Martin J.; Hamad, Charles; Howley, Thomas

    1998-01-01

    A structure of interlocking contingencies was designed to train and support managers' provision of effective feedback to subordinates, peers, and superiors at a large state residential institution for children with developmental disabilities. The system included formal scheduling of feedback, reinforcement, and goal setting. Increased feedback…

  3. Unifying screw geometry and matrix transformations

    SciTech Connect

    Samuel, A.E.; McAree, P.R.; Hunt, K.H. (Univ. of Melbourne, Parkville (Australia))

    1991-10-01

    Transformation matrices are widely used in robotics for kinematic analysis and trajectory planning. Screw geometry offers better geometric insight into such analyses. In this article the authors unify the two approaches through the use of invariant properties of orthogonal matrices under similarity transformations. They give a complete expression for the finite screw motion in terms of the entires of a 3 {times} 3 dual-number transformation matrix. Their analysis suggests that the finite screw is suitable for trajectory planning, and they develop a concise expression that gives the transformation matrix describing the displacement at each point along the path of the finite screw motion.

  4. Biodegradable Interference Screw Fixation Exhibits Pull-Out Force and Stiffness Similar to Titanium Screws

    Microsoft Academic Search

    Andreas Weiler; Henning J. Windhagen; Michael J. Raschke; Andrea Laumeyer; Reinhard F. G. Hoffmann

    1998-01-01

    Recently, increased interest in biodegradable interference screws for bone-tendon-bone graft fixation has led to numerous screws becoming available. The implants are made from different polymers and have different designs, which might influence their mechanical properties. Several studies have reported a wide range of mechanical results for these screws using different biomechanical models. The aim of the present study is to

  5. The Use of Mechanical Interlock in Dental Prosthesis

    Microsoft Academic Search

    Mohammed Rafiq Abdul Kadir; K. Osman; A. I. Zainuddin

    Good long term outcomes in prosthetic dentistry depends on the stability of its abutment-implant construct. One of the abutment\\u000a designs normally used is a cylindrical taper where interference fit is achieved on large contact pressure and frictional resistance\\u000a at the interface. Other designs include the screw and a combination of screw and taper. The stability of the implant body\\u000a relative

  6. Distal plate placement for distal radius fractures limits wrist motion

    Microsoft Academic Search

    Shingo Komura; Hiroyuki Tanahashi; Yoshihisa Yamada; Tatsuo Yokoi; Hidehiko Nonomura; Yasushi Suzuki

    Purpose  To investigate the influence of distal plate placement for distal radius fractures on risk of flexor tendon complications\\u000a and wrist motion by performing hardware removal.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and methods  Fourteen patients treated with a Synthes 2.4 mm juxta-articular LCP Distal Radius Plate underwent hardware removal at ?6 months\\u000a postoperatively when improvement of range of motion and grip strength were obtained. Location of plate placement,

  7. Fixed Bicortical Screw and Blade Implants as a Non-Standard Solution to an Edentulous (Toothless) Mandible

    PubMed Central

    Strecha, Juraj; Jurkovic, Richard; Siebert, Tomas; Prachar, Patrik; Bartakova, Sonia

    2010-01-01

    Aim This paper deals with the treatment of an atrophied toothless mandible with a fixing bridge carried by two non-standard implant systems. Methodology Four bicortical screws were implanted into the frontal part of the mandible and one implant on each side was placed into the distal area of the mandible as a support for a fixing bridge. Results During the years 2002 – 2007 the authors placed a total of 256 bicortical screw and 84 blade implants. During this period only four bicortical screws and one blade implant failed. The primary and secondary surgical success rate was therefore above 98%, while the prosthetic success rate was 100%. (Bridges which had to be re-fabricated due to implant failure were not taken into account.) Conclusion This approach is recommended as a highly successful and affordable option for a wide range of patients. PMID:20737937

  8. 3D Mapping of Safe and Danger Zones in the Maxilla and Mandible for the Placement of Intermaxillary Fixation Screws

    PubMed Central

    Purmal, Kathiravan; Alam, Mohammad Khursheed; Pohchi, Abdullah; Abdul Razak, Noor Hayati

    2013-01-01

    Intermaxillary (IMF) screws feature several advantages over other devices used for intermaxillary fixation, but using cone beam computed tomography (CBCT) scans to determine the safe and danger zones to place these devices for all patients can be expensive. This study aimed to determine the optimal interradicular and buccopalatal/buccolingual spaces for IMF screw placement in the maxilla and mandible. The CBCT volumetric data of 193 patients was used to generate transaxial slices between the second molar on the right to the second molar on the left in both arches. The mean interradicular and buccopalatal/buccolingual distances and standard deviation values were obtained at heights of 2, 5, 8 and 11 mm from the alveolar bone crest. An IMF screw with a diameter of 1.0 mm and length of 7 mm can be placed distal to the canines (2 - 11 mm from the alveolar crest) and less than 8 mm between the molars in the maxilla. In the mandible, the safest position is distal to the first premolar (more than 5 mm) and distal to the second premolar (more than 2 mm). There was a significant difference (p<0.05) between the right and left quadrants. The colour coding 3D template showed the safe and danger zones based on the mesiodistal, buccopalatal and buccolingual distances in the maxilla and mandible.The safest sites for IMF screw insertion in the maxilla were between the canines and first premolars and between the first and second molars. In the mandible, the safest sites were between the first and second premolars and between the second premolar and first molar. However, the IMF screw should not exceed 1.0 mm in diameter and 7 mm in length. PMID:24367643

  9. Improved screw theory using second order terms

    Microsoft Academic Search

    Jun Takamatsu; H. Kimura; Katsushi Ikeuchi

    2002-01-01

    The local displacement of an object is very useful for deciding grasp stability, generating trajectories, recognizing assembly tasks, and so on. To calculate this displacement, the screw theory is employed. It is equivalent to the first order Taylor expansion of the displacement. The screw theory is very convenient, because the displacement is formulated as simultaneous linear inequalities, and a powerful

  10. Genetics and Pathogenesis of Distal Muscular Dystrophies

    Microsoft Academic Search

    Bjarne Udd

    \\u000a Distal myopathies are distal muscular dystrophies because they are genetic disorders with progressive loss of muscle tissue.\\u000a The true distal dystrophies not only show a distal onset; they also remain more distal than proximal throughout the course\\u000a of the disease. Currently almost 20 different entities of distal muscular dystrophies have been genetically determined, compared\\u000a to just five entities delineated on

  11. 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. PMID:22960611

  12. Scarf osteotomy without screw fixation

    Microsoft Academic Search

    M. Maestro

    2007-01-01

    The scarf osteotomy is now well recognised as reliable and effective to contribute to the correction of the majority of hallux\\u000a valgus. The challenge remains for the correction of severe deformities with metatarsus varus angle >18? and Distal Metatarsal\\u000a Articular Angle (DMAA) >15?. In order to significantly improve in 3D the metatarsal head displacements, our scarf design became more oblique,

  13. Distal convoluted tubule.

    PubMed

    McCormick, James A; Ellison, David H

    2015-01-01

    The distal convoluted tubule (DCT) is a short nephron segment, interposed between the macula densa and collecting duct. Even though it is short, it plays a key role in regulating extracellular fluid volume and electrolyte homeostasis. DCT cells are rich in mitochondria, and possess the highest density of Na+/K+-ATPase along the nephron, where it is expressed on the highly amplified basolateral membranes. DCT cells are largely water impermeable, and reabsorb sodium and chloride across the apical membrane via electroneurtral pathways. Prominent among this is the thiazide-sensitive sodium chloride cotransporter, target of widely used diuretic drugs. These cells also play a key role in magnesium reabsorption, which occurs predominantly, via a transient receptor potential channel (TRPM6). Human genetic diseases in which DCT function is perturbed have provided critical insights into the physiological role of the DCT, and how transport is regulated. These include Familial Hyperkalemic Hypertension, the salt-wasting diseases Gitelman syndrome and EAST syndrome, and hereditary hypomagnesemias. The DCT is also established as an important target for the hormones angiotensin II and aldosterone; it also appears to respond to sympathetic-nerve stimulation and changes in plasma potassium. Here, we discuss what is currently known about DCT physiology. Early studies that determined transport rates of ions by the DCT are described, as are the channels and transporters expressed along the DCT with the advent of molecular cloning. Regulation of expression and activity of these channels and transporters is also described; particular emphasis is placed on the contribution of genetic forms of DCT dysregulation to our understanding. PMID:25589264

  14. Metal-organic frameworks with dynamic interlocked components.

    PubMed

    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 (13)C and (2)H 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. PMID:22614379

  15. 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. [Argonne National Lab., IL (United States). Advanced Photon Source

    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.

  16. A geometrical introduction to screw theory

    NASA Astrophysics Data System (ADS)

    Minguzzi, E.

    2013-05-01

    This work introduces screw theory, a venerable but little known theory aimed at describing rigid body dynamics. This formulation of mechanics unifies in the concept of screw the translational and rotational degrees of freedom of the body. It captures a remarkable mathematical analogy between mechanical momenta and linear velocities, and between forces and angular velocities. For instance, it clarifies that angular velocities should be treated as applied vectors and that, under the composition of motions, they sum with the same rules of applied forces. This work provides a short and rigorous introduction to screw theory intended for an undergraduate and general readership.

  17. A geometrical introduction to screw theory

    E-print Network

    E. Minguzzi

    2012-11-20

    This work introduces screw theory, a venerable but yet little known theory aimed at describing rigid body dynamics. This formulation of mechanics unifies in the concept of screw the translational and rotational degrees of freedom of the body. It captures a remarkable mathematical analogy between mechanical momenta and linear velocities, and between forces and angular velocities. For instance, it clarifies that angular velocities should be treated as applied vectors and that, under the composition of motions, they sum with the same rules of applied forces. This work provides a short and rigorous introduction to screw theory intended to an undergraduate and general readership.

  18. Solution-Phase Dynamic Assembly of Permanently Interlocked Aryleneethynylene Cages through Alkyne Metathesis.

    PubMed

    Wang, Qi; Yu, Chao; Long, Hai; Du, Ya; Jin, Yinghua; Zhang, Wei

    2015-06-22

    Highly stable permanently interlocked aryleneethynylene molecular cages were synthesized from simple triyne monomers using dynamic alkyne metathesis. The interlocked complexes are predominantly formed in the reaction solution in the absence of any recognition motif and were isolated in a pure form using column chromatography. This study is the first example of the thermodynamically controlled solution-phase synthesis of interlocked organic cages with high stability. PMID:25959769

  19. Primary Stability of Interference Screw FixationInfluence of Screw Diameter and Insertion Torque

    Microsoft Academic Search

    Dieter Kohn; Christoph Rose

    1994-01-01

    Interference screw fixation is frequently used in anterior cruciate ligament reconstruction with the bone-patellar tendon-bone graft. There have been no data available about the influence of screw diameter and insertion torque on primary stability. We designed a cadaveric study using paired knees to analyze the comparative effectiveness of 20-mm long screws of different diam eters (9 mm versus 7 mm)

  20. Screw pull-out force is dependent on screw orientation in an anterior cervical plate construct.

    PubMed

    DiPaola, Christian P; Jacobson, Justin A; Awad, Hani; Conrad, Bryan P; Rechtine, Glenn R

    2007-07-01

    Two common justifications for orienting cervical screws in an angled direction is to increase pull-out strength and to allow use of longer screws. This concept is widely taught and has guided implant design. Fixed versus variable angle systems may offer strength advantages. The purpose of our study is to test the influence of screw orientation and plate design on the maximum screw pull-out load. Variable and fixed angle 4.0 x 15 mm and 4.0 x 13 mm self-tapping screws were used to affix a Medtronic Atlantis cervical plate to polyurethane foam bone samples (density 0.160/cm). This synthetic product is a model of osteoporotic cancellous bone. The fixed angle screws can only be placed at 12 degrees convergent to the midline and 12 degrees in the cephalad/caudal ("12 degrees up and in") direction. Three groups were tested: (1) all fixed angle screws, (2) variable angle, all screws 12 degrees up and in, (3) variable angle, all screws 90 degrees to the plate. Plate constructs were pulled off with an Instron DynaMight 8841 servohydrolic machine measuring for maximum screw pull-out force. There was no difference between group 1, fixed angle (288.4 +/- 37.7 N) (mean +/- SD) and 2, variable angle group (297.7 +/- 41.31 N P< or =0.73). There was a significant increase in maximum pull-out force to failure for the construct with all screws at 90 degrees (415.2+/-17.4 N) compared with all screws 12 degrees "up and in" (297.4 +/- 41.3 N, P< or =0.0016). Group 3 done with 13 mm screws, showed a trend toward better pull-out strength, compared to group 2 w/15 mm screws (345.2 +/- 20.5 vs. 297.4 +/- 41.3, P< or =0.06). In this plate pull-out model, screw orientation influences maximum force to failure. When all 4 screws are 90 degrees to the plate the construct has the greatest ability to resist pullout. Fixed angle designs show no advantage over variable angle. These findings are contrary to current teaching. PMID:17607102

  1. Results of uncemented distal locked prosthesis in revision hip arthroplasty with proximal femoral bone loss: A retrospective study

    PubMed Central

    Agarwala, Sanjay; Jhunjhunwala, Hari Ram; Pachore, Jawahir A; Joglekar, Siddharth B; Eachempati, Krishna Kiran

    2013-01-01

    Introduction: Management of bone loss is a challenge in revision total hip arthroplasty (THA). A retrospective review was performed to study the use of uncemented distal locked prosthesis in cases with proximal femoral bone loss. Materials and Methods: Uncemented stems with distal interlocking were used in 65 hips during revision THAs with 38 hips having Paprosky IIIB/IV defects between January 1998 and February 2004. There were 48 males and 17 females in the study with an average age of 53 years (range 30-80 years). Radiographic and clinical outcome evaluation using the Harris hip score (HHS) were performed. Results: An improvement in HHS (mean: 33 points) was observed at final followup (mean: 9 years). Regeneration of proximal bone stock was observed without signs of loosening or subsidence and none of the stems were revised. Three patients developed recurrent dislocation while one had a stem subsidence of 1cm following removal of interlocking bolts. Conclusion: Uncemented distal locked prosthesis provide adequate stability in revision THA, aiding the reconstruction of bony deficiencies while avoiding the disadvantages of fully porous or cemented implants. PMID:23533020

  2. Rotordynamics of Twin-Screw Pumps 

    E-print Network

    Aboel Hassan Muhammed, Ameen

    2013-02-26

    geometry, the circumferential pressure field around the screws is not balanced, resulting in net dynamic and static pressures applied on the rotors. The research work presented here aims at building and verifying a model to predict both: (1) the exciting...

  3. Rotordynamics of Twin-Screw Pumps

    E-print Network

    Aboel Hassan Muhammed, Ameen

    2013-02-26

    geometry, the circumferential pressure field around the screws is not balanced, resulting in net dynamic and static pressures applied on the rotors. The research work presented here aims at building and verifying a model to predict both: (1) the exciting...

  4. Cycling Losses During Screw Air Compressor Operation 

    E-print Network

    Maxwell, J. B.; Wheeler, G.; Bushnell, D.

    1995-01-01

    Air compressors use 10-13 % of a typical industrial facilities' total electricity. Because they often operate at part load, their part load efficiency significantly affects plant energy cost. An intensive study of screw air compressor part load...

  5. Semi-Empirical Screw Compressor Chiller Model

    E-print Network

    Nelson, I. C.; Culp, C.; Graves, R. D.

    Director, Energy Systems Laboratory College Station, TX USA Rhett D. Graves, P.E. Research Associate II, Department of Mechanical Engineering Mississippi State University Starkville, MS USA ABSTRACT A screw chiller model which is based on a first...

  6. 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.

  7. National Synchrotron Light Source medical personnel protection interlock

    SciTech Connect

    Buda, S.; Gmuer, N.F.; Larson, R.; Thomlinson, W.

    1998-11-01

    This report is founded on reports written in April 1987 by Robert Hettel for angiography operations at the Stanford Synchrotron Research Laboratory (SSRL) and a subsequent report covering angiography operations at the National Synchrotron Light Source (NSLS); BNL Informal Report 47681, June 1992. The latter report has now been rewritten in order to accurately reflect the design and installation of a new medical safety system at the NSLS X17B2 beamline Synchrotron Medical Research Facility (SMERF). Known originally as the Angiography Personnel Protection Interlock (APPI), this system has been modified to incorporate other medical imaging research programs on the same beamline and thus the name has been changed to the more generic Medical Personnel Protection Interlock (MPPI). This report will deal almost exclusively with the human imaging (angiography, bronchography, mammography) aspects of the safety system, but will briefly explain the modular aspects of the system allowing other medical experiments to be incorporated. This MPPI report is organized such that the level of detail changes from a general overview to detailed engineering drawings of the hardware system. The general overview is presented in Section 1.0, MPPI Operational Mode and Procedures. The various MPPI components are described in detail in Section 2.0. Section 3.0 presents some simplified logic diagrams and accompanying text. This section was written to allow readers to become familiar with the logic system without having to work through the entire set of detailed engineering drawings listed in the Appendix. Detailed logic specifications are given in Section 4.0. The Appendix also contains copies of the current MPPI interlock test procedures for Setup and Patient Modes.

  8. 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.

  9. Distal tibia fractures: management and complications of 101 cases.

    PubMed

    Joveniaux, Pierre; Ohl, Xavier; Harisboure, Alain; Berrichi, Aboubekr; Labatut, Ludovic; Simon, Patrick; Mainard, Didier; Vix, Nicolas; Dehoux, Emile

    2010-04-01

    Distal tibia fractures are complex injuries with a high complication rate. In this retrospective and multicentre study we attempted to detail complications and outcomes of this type of injury in order to determine predictive factors of poor results. Between 2002 and 2004, 104 patients were admitted for 105 distal tibia fractures. One hundred patients (101 fractures) were reviewed with an average follow-up of 19 months (range, 12-46). Internal fixation, external fixation, limited internal fixation (K-wires or screws), intramedullary nailing and conservative treatment were used. Outcome parameters included occurrence of complications, radiographic analysis, evaluation of the American Orthopaedic Foot and Ankle Society (AOFAS) ankle score and measures of the ankle range of motion. The average functional score was 76 points (range, 30-100 points), and complications occurred in 30 patients. Predictive factors of poor results were fracture severity, complications, malunion and the use of external fixation. We believe that external fixation must be reserved for trauma with severe skin injury, as a temporary solution in a two-staged protocol. For other cases, we recommend ORIF with early mobilisation. PMID:19554328

  10. Management of fractures of the distal third tibia by minimally invasive plate osteosynthesis – A prospective series of 50 patients

    PubMed Central

    Paluvadi, Siddhartha Venkata; Lal, Hitesh; Mittal, Deepak; Vidyarthi, Kandarp

    2014-01-01

    Background Minimally invasive plate osteosynthesis (MIPO) is an established technique for fixation of fractures of the distal third tibia. Our study aimed to manage intra articular and extraarticular fractures of the distal third tibia by the minimally invasive plate osteosynthesis technique and follow them prospectively. Clinical and radiological outcomes were studied and clinical indications & efficacy of the procedure reviewed. Though many studies on the subject have been done previously, these have been retrospective reviews or small series. Methods From May 2010 to May 2013, 50 patients of closed distal tibial fractures were operated by MIPO technique with a distal tibial anatomical locking plate having 4.5/5 proximal and 3.5/4 distal screw holes. The follow up duration was for 3 years. Results The mean fracture healing time was 21.4 weeks (range 16–32 weeks) and average AOFAS score 95.06 was out of a total possible 100 points. At last follow up, superficial infection occurred in 5 patients (10%); deep infection, implant failure and malunion in 1-patient each (2%). Conclusion MIPO technique provides good, though slightly delayed bone healing and decreases incidence of nonunion and need for bone grafting. This technique should be used in distal tibia fractures where locked nailing cannot be done like fractures with small distal metaphyseal fragments, vertical splits, markedly comminuted fractures and in fractures with intra-articular extension. PMID:25983486

  11. 49 CFR 236.401 - Automatic block signal system and interlocking standards applicable to traffic control systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Automatic block signal system and interlocking standards applicable...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...Standards § 236.401 Automatic block signal system and interlocking standards...

  12. 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

    ...2011-10-01 false Automatic block signal system and interlocking standards applicable...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...Standards § 236.401 Automatic block signal system and interlocking standards...

  13. 49 CFR 236.401 - Automatic block signal system and interlocking standards applicable to traffic control systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Automatic block signal system and interlocking standards applicable...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...Standards § 236.401 Automatic block signal system and interlocking standards...

  14. 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

    ...2010-10-01 false Automatic block signal system and interlocking standards applicable...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...Standards § 236.401 Automatic block signal system and interlocking standards...

  15. 49 CFR 236.401 - Automatic block signal system and interlocking standards applicable to traffic control systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Automatic block signal system and interlocking standards applicable...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...Standards § 236.401 Automatic block signal system and interlocking standards...

  16. 12 CFR 250.412 - Interlocking relationships between member bank and insurance company-mutual fund complex.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Interlocking relationships between member bank and...250.412 Interlocking relationships between member bank and...minimal for the foreseeable future. However, it was understood...been scrupulous in their relationships” to the banks in...

  17. [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. PMID:25398510

  18. Interlocking Detachable Coil Occlusion in the Endovascular Treatment of Intracranial Aneurysms: Preliminary Results

    Microsoft Academic Search

    H. Saruhan Cekirge; Isil Saatci; Murat M. Firat; Ferhun Balkanci; Aytekin Besim

    PURPOSE: To present our preliminary experience with the recently developed interlocking de- tachable coils in the treatment of intracranial aneurysms. METHODS: Two aneurysms of the basilar tip, two of the internal carotid artery, and one of the posterior inferior cerebellar artery were treated by an endovascular technique using interlocking detachable coils. Three of the patients had undergone unsuccessful surgical clipping.

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

    Microsoft Academic Search

    M. Zaera-Sanz

    2009-01-01

    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

  20. Investigation of a polymer metal inter-locking technology for use

    E-print Network

    Grujicic, Mica

    injection over-molding PMH process but with an ,3 percent lower weight (of the polymer subcomponentInvestigation of a polymer metal inter-locking technology for use in load-bearing automotive ­ The purpose of this paper is to propose and analyse computationally a new concept for mechanical interlocking

  1. 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. PMID:25869451

  2. Maxillary sinus perforation by orthodontic anchor screws.

    PubMed

    Motoyoshi, Mitsuru; Sanuki-Suzuki, Rina; Uchida, Yasuki; Saiki, Akari; Shimizu, Noriyoshi

    2015-01-01

    To facilitate safe placement of orthodontic anchor screws (miniscrews), we investigated the frequency of maxillary sinus perforation after screw placement and the effect of sinus perforation on screw stability. Maxillary sinus perforations involving 82 miniscrews (diameter, 1.6 mm; length, 8 mm) were evaluated using cone-beam computed tomography. All miniscrews were placed in maxillary alveolar bone between the second premolar and first molar for anchorage for anterior retraction in patients undergoing first premolar extraction. The placement torque and screw mobility of each implant were determined using a torque tester and a Periotest device, and variability in these values in relation to sinus perforation was evaluated. Eight of the 82 miniscrews perforated the maxillary sinus. There was no case of sinusitis in patients with miniscrew perforation and no significant difference in screw mobility or placement torque between perforating and non-perforating miniscrews. The sinus floor was significantly thinner in perforated cases than in non-perforated cases. A sinus floor thickness of 6.0 mm or more is recommended in order to avoid miniscrew perforation of the maxillary sinus. (J Oral Sci 57, 95-100, 2015). PMID:26062857

  3. Distal Oblique Bundle Reconstruction and Distal Radioulnar Joint Instability

    PubMed Central

    Riggenbach, Michael D.; Conrad, Bryan P.; Wright, Thomas W.; Dell, Paul C.

    2013-01-01

    Background?This study created an anatomic reconstruction of the distal oblique bundle (DOB) of the interosseous membrane to determine its effect on distal radioulnar joint (DRUJ) instability and compare this technique with distal radioulnar ligament (DRUL) reconstruction. Questions/Purposes?We hypothesized that this reconstruction would provide equivalent stability to DRUL reconstruction and that combining the two techniques would enhance stability. Methods?Six cadaveric upper limbs were affixed to a custom frame. The volar/dorsal translation of the radius relative to the ulna was measured in 60° pronation, neutral, and 60° supination. Translation was sequentially measured with the DRUJ intact, with sectioned DRULs and triangular fibrocartilaginous complex (TFCC), and with sectioned DOBs. Reconstructions were performed on the DRULs, on the DOB tensioned in both neutral and supination, and employing both techniques. Results?The DOB reconstruction, tensioned both in the neutral position and in 60° supination, was more stable than the partial and complete instability in 6/6 specimens in pronation and the neutral position and in 5/6 specimens in supination. The DOB reconstruction and the DOB reconstruction tensioned in supination were more stable than the DRUL reconstruction in 4/6 patients. Combining the two techniques did not further reduce translation. Conclusions?The DOB reconstruction is capable of improving stability in the unstable DRUJ. PMID:24436838

  4. 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.

  5. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... “Warning: The safety and effectiveness of pedicle screw spinal systems have been established...requiring fusion with instrumentation. These conditions...pseudarthrosis). The safety and effectiveness of these...pedicle screw spinal systems should be...

  6. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... “Warning: The safety and effectiveness of pedicle screw spinal systems have been established...requiring fusion with instrumentation. These conditions...pseudarthrosis). The safety and effectiveness of these...pedicle screw spinal systems should be...

  7. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... “Warning: The safety and effectiveness of pedicle screw spinal systems have been established...requiring fusion with instrumentation. These conditions...pseudarthrosis). The safety and effectiveness of these...pedicle screw spinal systems should be...

  8. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... “Warning: The safety and effectiveness of pedicle screw spinal systems have been established...requiring fusion with instrumentation. These conditions...pseudarthrosis). The safety and effectiveness of these...pedicle screw spinal systems should be...

  9. KINEMATIC ANALYSIS OF LOWER MOBILITY COOPERATIVE ARMS BY SCREW THEORY

    E-print Network

    Paris-Sud XI, Université de

    KINEMATIC ANALYSIS OF LOWER MOBILITY COOPERATIVE ARMS BY SCREW THEORY Philip Long1 , St´ephane Caro.secondname}@irccyn.ec-nantes.fr Keywords: Cooperative Manipulators:Humanoid Robots: Screw theory Abstract: This paper studies the kinematic

  10. A geometrical introduction to screw theory

    E-print Network

    Minguzzi, E

    2012-01-01

    Since the addition of applied forces must take into account the line of action, applied forces do not belong to a vector space. Screw theory removes this geometrical limitation and solves other mechanical problems by unifying, in a single concept, the translational and rotational degrees of freedom. Although venerable this theory is little known. By introducing some innovations, I show how screw theory can help us to rapidly develop several standard and less standard results in classical mechanics. The connection with the Lie algebra of the group of rigid maps is clarified.

  11. Screw Systems, Singular Trajectories and DarbouxType Motions

    E-print Network

    Donelan, Peter

    Screw Systems, Singular Trajectories and Darboux­Type Motions M. W. Cocke and C. G. Gibson by the associated screw system. We present a classification of screw systems based on a Lie group representation body motions abound in theory and practice. The instantaneous centre of rotation for a continuous (or

  12. A Novel Pedicle Screw with Mobile Connection: A Pilot Study

    PubMed Central

    Oshima, Masashi; Ajiro, Yasumitsu; Uei, Hiroshi

    2014-01-01

    To prevent adjacent disc problems after spinal fusion, a pedicle screw with a mobile junction between the head and threaded shaft was newly developed. The threaded shaft of the screw has 10 degrees mobility in all directions, but its structure is to prevent abnormal translation and tilting. This screw was evaluated as follows: (1) endurance test: 106 times rotational stress was applied; (2) biological reactions: novel screws with a mobile head and conventional screws with a fixed head were inserted into the bilateral pedicles of the L3, L4, and L5 in two mini pigs with combination. Eight months after surgery, vertebral units with the screw rod constructs were collected. After CT scan, the soft and bony tissues around the screws were examined grossly and histologically. As a result, none of the screws broke during the endurance test stressing. The mean amount of abrasion wear was 0.0338?g. In the resected mini pig section, though zygapophyseal joints between fixed-head screws showed bony union, the amount of callus in the zygapophyseal joints connected with mobile-head screws was small, and joint space was confirmed by CT. No metalloses were noted around any of the screws. Novel screws were suggested to be highly durable and histologically safe. PMID:24724103

  13. Parameter estimation during automated screw insertions

    Microsoft Academic Search

    Mongkom Klingajay; Lakmal D. Seneviratne; Kaspar Althoefer

    2002-01-01

    Threaded fastenings are a common assembly method, accounting for over a quarter of all assembly operations. Threaded fastenings are popular because they permit easy disassembly for maintenance, repair, relocation and recycling. Screw insertions are typically carried out manually and are a difficult problem to automate. As a result there is very little published research on automating threaded fastenings, and most

  14. Computer simulation of screw dislocation in aluminum

    NASA Technical Reports Server (NTRS)

    Esterling, D. M.

    1976-01-01

    The atomic structure in a 110 screw dislocation core for aluminum is obtained by computer simulation. The lattice statics technique is employed since it entails no artificially imposed elastic boundary around the defect. The interatomic potential has no adjustable parameters and was derived from pseudopotential theory. The resulting atomic displacements were allowed to relax in all three dimensions.

  15. ROBOT WELDING TRAJECTORY PLANNING USING SCREW THEORY

    Microsoft Academic Search

    Renato Ventura; Bayan Henriques; Carlos Eduardo Pereira; Alexandre Queiroz Bracarense; Raul Guenther; Antonio O. Dourado; Daniel Martins

    This article presents a methodology for trajectory plannin g in robot welding applications, which handles parts with geometric restrictions . Differential kinematics are calc ulated using the screws theory and an optimal welding positi on (plain position) is obtained when defining the welding seque nce. The latter is the major contribution of the proposed methodology, since previous work have only

  16. A screw theory of static beams

    Microsoft Academic Search

    J. M. Selig; X. Ding

    2001-01-01

    We derive the deflection equation of a simple beam using the screw theory. The effects of tension, torsion and bending of the beam can be unified into a single equation. We begin by looking at the compliance matrix for small elements of the beam. This is loosely based on the work by von Mises (1924). We reproduce von Mises' results

  17. Screw Compressor Characteristics for Helium Refrigeration Systems

    Microsoft Academic Search

    Venkatarao Ganni; Peter Knudsen; Jonathan Creel; Dana Arenius; Fabio Casagrande; Matt Howell

    2008-01-01

    The oil injected screw compressors have practically replaced all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, minimal vibration, reliability and capability of handling helium's high heat of compression. At the present state of compressor system designs for helium systems, typically two-thirds of the lost input power is due to the compression system.

  18. A model for biomass screw feeding

    Microsoft Academic Search

    Jianjun Dai; John R. Grace

    2008-01-01

    Successful feeding is critical to biomass utilization processes, but trouble-free delivery is difficult due to particle heterogeneity, physical characteristics and moisture content. A model, extended from previous models in the literature, is proposed to delineate what limits screw feeding in terms of the mechanisms of blockage and to predict torque requirements for biomass materials. Predictions on feeding of wood pellets,

  19. Direct Arthroscopic Distal Clavicle Resection

    PubMed Central

    Lervick, Gregory N

    2005-01-01

    Degenerative change involving the acromioclavicular (AC) is frequently seen as part of a normal aging process. Occasionally, this results in a painful clinical condition. Although AC joint symptoms commonly occur in conjunction with other shoulder pathology, they may occur in isolation. Treatment of isolated AC joint osteoarthritis is initially non-surgical. When such treatment fails to provide lasting relief, surgical treatment is warranted. Direct (superior) arthroscopic resection of the distal (lateral) end of the clavicle is a successful method of treating the condition, as well as other isolated conditions of the AC joint. The following article reviews appropriate patient evaluation, surgical indications and technique. PMID:16089089

  20. [Analysis of tendon injuries accompanying distal radius fractures using volar locking plates].

    PubMed

    Zenke, Yukichi; Oshige, Toshihisa; Menuki, Kunitaka; Yamanaka, Yoshiaki; Murai, Teppei; Furukawa, Kayoko; Sakai, Akinori

    2014-12-01

    We examined 6 cases of tendon injuries that accompanied distal radius fractures using volar locking plate between April 2006 and March 2012. Male: one case, female: five cases, average age 57.0 (33~70) years old. The fracture type was A2 in one case, A3 in four cases, and C2 in one case by AO classification. The average period for operation waiting was 2.7 days. We analyzed the time of occurrence of tendon rupture (extensor pollicis longus (EPL)?flexor pollicis longus (FPL)), the existence or not of screw prominence and dorsal roof fragment, and the positioning of the plate setting. The tendon ruptures were EPL in four cases, and FPL in two cases. The average period of rupture occurrence was 86.8 (1~182) days. In four EPL tendon ruptures we recognized one marked screw prominence (16.7%), and two dorsal roof fragments (50%), both showing widespread displacement. Moreover, we recognized the malposition of the plate setting in the two cases of FPL tendon rupture (100%). The incidence of tendon ruptures accompanying distal radius fractures using volar locking plates was not low at all, therefore we should more pay attention to the prevention of this occurrence. PMID:25501757

  1. 12 CFR 250.411 - Interlocking relationships between member bank and variable annuity insurance company.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...GOVERNORS OF THE FEDERAL RESERVE SYSTEM (CONTINUED) MISCELLANEOUS INTERPRETATIONS Interpretations of Section 32 of the Glass-Steagall Act § 250.411 Interlocking relationships between member bank and variable annuity insurance...

  2. 30 CFR 75.819 - Motor-starter enclosures; barriers and interlocks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.819 Motor-starter enclosures; barriers and interlocks. Compartment...

  3. Numerical\\/analytical methods to evaluate the mechanical behavior of interlock composites

    Microsoft Academic Search

    Samer Nehme; Ali Hallal; Farouk Fardoun; Rafic Younes; Benjamin Hagege; Zoheir Aboura; Malk Benzeggagh; Fadi Hage Chehade

    2011-01-01

    It is seen that 2.5D interlocks are particular reinforcements for high advanced applications (i.e., spatial and aeronautics fields) that are believed to have a high structural potential. This kind of reinforcement entails to consider the composite as a structure because interlocks are built by crossing the warp yarns with the weft (or fill) yarns in the three directions. In this

  4. Strategy for salvage pedicle screw placement: A technical note

    PubMed Central

    Fujibayashi, Shunsuke; Takemoto, Mitsuru; Neo, Masashi; Matsuda, Shuichi

    2013-01-01

    Background Salvage surgery for failed lumbar spine fusion with a loosened pedicle screw is challenging. In general, the strategy includes replacement with larger and longer pedicle screws, augmentation with polymethylmethacrylate cement or hydroxyapatite granules, and extension of fused segments. The purpose of this study is to introduce a new technique for pedicle screw replacement after failed lumbar spine fusion. Methods Five salvage operations were performed using a different trajectory (DT) pedicle screw replacement technique based on 3-dimensional radiological information. Position of the alternative pedicle screws was planned carefully on the computer screen of a computed tomography-based navigation system before the operation. To obtain sufficient initial stability, 1 of 2 techniques was chosen, depending on the patient. One technique created a completely new route, which did not interfere with the existing screw hole, and the other involved penetration of the existing screw hole. Results DT pedicle screws were replaced successfully according to the preoperative plan. In all patients, bony union were achieved at the final follow-up period without any instrument failure. Extension of the fused segments could be avoided by using the DT pedicle screw replacement technique combined with transforaminal lumbar interbody fusion. Conclusions The DT pedicle screw replacement technique is a treatment option for salvage lumbar spine surgery. Clinical relevance The current technique is a treatment option for salvage operations that can both avoid extension of a fused segment and achieve successful bony union. PMID:25694906

  5. 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

  6. Interlocked DNA nanostructures controlled by a reversible logic circuit.

    PubMed

    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

  7. Biomass granular screw feeding: An experimental investigation

    Microsoft Academic Search

    Jianjun Dai; John R. Grace

    2011-01-01

    Successful feeding is critical to biomass utilization processes, but difficult due to the heterogeneity, physical properties and moisture content of the particles. The objectives of the present study were to find the mechanisms of blockage in screw feeding and to determine the effects of particle mean size (0.5–15mm), size distribution, shape, moisture content (10–60%), density and compressibility on biomass particle

  8. 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. PMID:25663513

  9. 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

  10. Screw dislocations in the field theory of elastoplasticity

    NASA Astrophysics Data System (ADS)

    Lazar, Markus

    2002-10-01

    A (microscopic) static elastoplastic field theory of dislocations with moment and force stresses is considered. The relationship between the moment stress and the Nye tensor is used for the dislocation Lagrangian. We discuss the stress field of an infinitely long screw dislocation in a cylinder, a dipole of screw dislocations and a coaxial screw dislocation in a finite cylinder. The stress fields have no singularities in the dislocation core and they are modified in the core due to the presence of localized moment stress. Additionally, we calculated the elastoplastic energies for the screw dislocation in a cylinder and the coaxial screw dislocation. For the coaxial screw dislocation we find a modified formula for the so-called Eshelby twist which depends on a specific intrinsic material length.

  11. Screw dislocations in the field theory of elastoplasticity

    E-print Network

    Markus Lazar

    2002-09-30

    A (microscopic) static elastoplastic field theory of dislocations with moment and force stresses is considered. The relationship between the moment stress and the Nye tensor is used for the dislocation Lagrangian. We discuss the stress field of an infinitely long screw dislocation in a cylinder, a dipole of screw dislocations and a coaxial screw dislocation in a finite cylinder. The stress fields have no singularities in the dislocation core and they are modified in the core due to the presence of localized moment stress. Additionally, we calculated the elastoplastic energies for the screw dislocation in a cylinder and the coaxial screw dislocation. For the coaxial screw dislocation we find a modified formula for the so-called Eshelby twist which depends on a specific intrinsic material length.

  12. Treatment of osteoporotic distal radius fractures

    Microsoft Academic Search

    David Ring; Jesse B. Jupiter

    2005-01-01

    Fracture of distal radius is most commonly an injury of the fit osteoporotic patient. As the population and health of older individuals continue to expand, osteoporotic distal radius fractures will become increasingly common. While many older patients have limited functional demands and can accept some deformity and wrist dysfunction, others remain very active into older age and desire optimal wrist

  13. The gauge theory of dislocations: A nonuniformly moving screw dislocation

    NASA Astrophysics Data System (ADS)

    Lazar, Markus

    2010-07-01

    We investigate the nonuniform motion of a straight screw dislocation in infinite media in the framework of the translational gauge theory of dislocations. The equations of motion are derived for an arbitrarily moving screw dislocation. The fields of the elastic velocity, elastic distortion, dislocation density and dislocation current surrounding the arbitrarily moving screw dislocation are derived explicitly in the form of integral representations. We calculate the radiation fields and the fields depending on the dislocation velocities.

  14. Screw theoretic view on dynamics of spatially compliant beam

    Microsoft Academic Search

    Xi-lun Ding; J. M. Selig

    2010-01-01

    Beams with spatial compliance can be deformed as bending in a plane, twisting, and extending. In terms of the screw theory\\u000a on rigid body motions, the concept of “deflection screw” is introduced, a spatial compliant beam theory via the deflection\\u000a screw is proposed, and the spatial compliance of such a beam system is presented and analysed based on the material

  15. 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.

  16. 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

  17. Genetics Home Reference: Distal hereditary motor neuropathy, type V

    MedlinePLUS

    ... OMIM Genetic disorder catalog Conditions > Distal hereditary motor neuropathy, type V On this page: Description Genetic changes ... Reviewed August 2009 What is distal hereditary motor neuropathy, type V? Distal hereditary motor neuropathy, type V ...

  18. Genetics Home Reference: Distal hereditary motor neuropathy, type II

    MedlinePLUS

    ... OMIM Genetic disorder catalog Conditions > Distal hereditary motor neuropathy, type II On this page: Description Genetic changes ... Reviewed August 2009 What is distal hereditary motor neuropathy, type II? Distal hereditary motor neuropathy, type II ...

  19. Postfusion pullout strength comparison of a novel pedicle screw with classical pedicle screws on synthetic foams.

    PubMed

    Arslan, Arslan K; Demir, Teyfik; Ormeci, Mehmet F; Camu?cu, Necip; Türeyen, Kudret

    2013-02-01

    Pullout is a very common failure mode on the use of pedicle screws. Numerous studies were completed to increase the pullout strength of pedicle screws especially for osteoporotic bones. In this study, a previously designed pedicle screw type was tested before and after fusion condition. Synthetic polyurethane foams were used in all tests. Three different grades of foams were used in tests to simulate severely osteoporotic, osteoporotic, and healthy bones. Test blocks were produced and characterized in our clinical biomechanics laboratory. Foaming of polyurethane was accepted as fusion process (bone in growth). Pedicle screw including radial holes (new design) was tested both before and after the fusion. It also exhibited remarkably higher pullout strength after fusion than before fusion and most of other alternatives stated in the literature. In total, 70% higher pullout strength was achieved with new design after fusion. On the other hand, new design did not dominate other alternatives when comparison was carried out on severely osteoporotic and healthy bones. To the knowledge of the authors, this is the first study investigating the postfusion properties on synthetic foams. PMID:23513982

  20. 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. PMID:19890935

  1. Modeling bicortical screws under a cantilever bending load.

    PubMed

    James, Thomas P; Andrade, Brendan A

    2013-12-01

    Cyclic loading of surgical plating constructs can precipitate bone screw failure. As the frictional contact between the plate and the bone is lost, cantilever bending loads are transferred from the plate to the head of the screw, which over time causes fatigue fracture from cyclic bending. In this research, analytical models using beam mechanics theory were developed to describe the elastic deflection of a bicortical screw under a statically applied load. Four analytical models were developed to simulate the various restraint conditions applicable to bicortical support of the screw. In three of the models, the cortical bone near the tip of the screw was simulated by classical beam constraints (1) simply supported, (2) cantilever, and (3) split distributed load. In the final analytical model, the cortices were treated as an elastic foundation, whereby the response of the constraint was proportional to screw deflection. To test the predictive ability of the new analytical models, 3.5?mm cortical bone screws were tested in a synthetic bone substitute. A novel instrument was developed to measure the bending deflection of screws under radial loads (225?N, 445?N, and 670?N) applied by a surrogate surgical plate at the head of the screw. Of the four cases considered, the analytical model utilizing an elastic foundation most accurately predicted deflection at the screw head, with an average difference of 19% between the measured and predicted results. Determination of the bending moments from the elastic foundation model revealed that a maximum moment of 2.3?N m occurred near the middle of the cortical wall closest to the plate. The location of the maximum bending moment along the screw axis was consistent with the fracture location commonly observed in clinical practice. PMID:24105350

  2. Screw-type pump for coal feeding

    SciTech Connect

    Hilbert, J.D. Jr.

    1983-05-01

    This article describes the Type-M pumps system, which provides the reliable and accurate coal feeding needed for the success of fluidized-bed combustion and other coal-firing requirements. The Type-M pump feed unit provides the safety feature with its internal flapper valve to prevent the possibility of blowback. It features bearing supports at both ends of the screw impeller shaft which permits smooth running and maintenance-free operation under variable feed and light load conditions. It has demonstrated its capability to handle not only finely pulverized coal but also coarse coal as well as a mixture of coarse coal and 1/8 x 0 limestone.

  3. 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.

  4. Evaluation of a fast PLC module in prospect of the LHC beam interlock system

    E-print Network

    Zaera-Sanz, Manuel

    2005-01-01

    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 mseconds. Siemens has introduced a “so called” fast module (FM352-5 Boolean Processor) that 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 note publishes the results of this study. As well, this note could be useful for other applications requiring fast processing using a PLC.

  5. Fault analysis of the DIII-D neutral beam safety interlock system

    SciTech Connect

    Phillips, J.C.; Colleraine, A.P.; Haskovec, J.S.; Hong, R.; Kim, J.; Sleaford, B.W.; Tooker, J.F.; Wight, J.J.

    1987-10-01

    The DIII-D neutral beam injection systems (NBIS) at GA Technologies rely on a substantial array of control and instrumentation for routine operation. Functions include shot sequencing, power supply control, vacuum control, and valve control, long with interlocks for safequarding personnel and equipment. Failures resulting from improper operation of the neutral beamlines, their power supplies, and supporting services have the potential to cause extensive damage to personnel, equipment, and beamline components, as well as delay of the experimental schedule. This paper will address only equipment and component failures. Intelligence and control are distributed over dissimilar types of equipment in separate locations. An analysis has been made of the possible failure modes of the subsystems and the interlocking of systems and operations. This has helped us to improve the design of the safety interlock system and to minimize the risk to the NBIS project. The analysis technique will be presented and possible outcomes of typical failure modes explored. 5 refs., 2 figs.

  6. 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. PMID:25389631

  7. Joining mechanism with stem tension and interlocked compression ring

    SciTech Connect

    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.

  8. Screw dislocation in zirconium: an ab initio study Emmanuel Clouet

    E-print Network

    Paris-Sud XI, Université de

    Screw dislocation in zirconium: an ab initio study Emmanuel Clouet CEA, DEN, Service de Recherches in zirconium is controlled by 1/3 1¯210 screw dislocations gliding in the prism planes of the hexagonal close zirconium and is known to be related to the number of valence electrons in the d band. We use ab initio

  9. Accuracy analysis of SCARA industrial robot based on screw theory

    Microsoft Academic Search

    Zhao Liang; Su Meng; Diao Changkun

    2011-01-01

    Based on an analysis of error sources of industrial robots, we build a pose error model of industrial robots with screw theory, which overcomes the defect that the error on the y-axis could not be reflected by the classical D-H parameter method. Given the error sources which influence the end- executor's accuracy, we established a screw representation of the static

  10. Manufacturing of the composite screw rotors by resin transfer molding

    Microsoft Academic Search

    Young Goo Kim; Dai Gil Lee; Park Kyoun Oh

    1995-01-01

    A screw-type pump with at least two rotors that are composed of male and female rotors with helical extending lands and grooves is increasingly used because it has a smaller weight to power ratio and produces less noise and vibration compared to conventional reciprocating pumps.Most male and female rotors of the screw type pump have been manufactured by machining. The

  11. The distal hereditary motor neuropathies.

    PubMed

    Rossor, Alexander M; Kalmar, Bernadett; Greensmith, Linda; Reilly, Mary M

    2012-01-01

    The distal hereditary motor neuropathies (dHMN) comprise a heterogeneous group of diseases that share the common feature of a length-dependent predominantly motor neuropathy. Many forms of dHMN have minor sensory abnormalities and/or a significant upper-motor-neuron component, and there is often an overlap with the axonal forms of Charcot-Marie-Tooth disease (CMT2) and with juvenile forms of amyotrophic lateral sclerosis and hereditary spastic paraplegia. Eleven causative genes and four loci have been identified with autosomal dominant, recessive and X-linked patterns of inheritance. Despite advances in the identification of novel gene mutations, 80% of patients with dHMN have a mutation in an as-yet undiscovered gene. The causative genes have implicated proteins with diverse functions such as protein misfolding (HSPB1, HSPB8, BSCL2), RNA metabolism (IGHMBP2, SETX, GARS), axonal transport (HSPB1, DYNC1H1, DCTN1) and cation-channel dysfunction (ATP7A and TRPV4) in motor-nerve disease. This review will summarise the clinical features of the different subtypes of dHMN to help focus genetic testing for the practising clinician. It will also review the neuroscience that underpins our current understanding of how these mutations lead to a motor-specific neuropathy and highlight potential therapeutic strategies. An understanding of the functional consequences of gene mutations will become increasingly important with the advent of next-generation sequencing and the need to determine the pathogenicity of large amounts of individual genetic data. PMID:22028385

  12. Perioperative management of distal pancreatectomy

    PubMed Central

    Fujino, Yasuhiro

    2015-01-01

    Recent advances in surgical techniques and perioperative management have markedly reduced operative morbidity after distal pancreatectomy (DP). However, some questions remain regarding the protocol for the perioperative management of DP, in particular, with regard to the development of pancreatic fistula (PF). A review of DP was therefore conducted in order to standardize the management of patients for a favorable outcome. Overall, operative technique and perioperative management emerged as two critical factors contributing to favorable outcome in DP patients. As for the operative method, surgical and closure techniques exhibited differences in outcome. Laparoscopic DP generally yields more favorable perioperative outcomes compared to open DP, and is applicable for benign tumors and some ductal carcinomas of the pancreas. Robotic DP is also available for safe pancreatic surgery. En bloc celiac axis resection offers a high R0 resection rate and potentially allows for some local control in the case of advanced pancreatic cancer. Following resection, staple closure was not found to reduce the rate of PF when compared to hand-sewn closure. In addition, ultrasonic dissection devices, fibrin glue sealing, and staple closure with mesh reinforcement were shown to significantly reduce PF, although there was some bias in these studies. In perioperative management, both preoperative and postoperative treatment affected outcome. First, preoperative endoscopic pancreatic stenting may be an effective prophylactic measure against fistula development following DP in selected patients. Second, in postoperative management, a multifactorial approach including prophylactic antibiotics improved high surgical site infection rates following complex hepato-pancreato-biliary surgery. Furthermore, although conflicting results have been reported, somatostatin analogues should be administered selectively to patients considered to have a high risk for PF. Finally, careful drain management also facilitates a favorable outcome in patients with PF after DP. The results of the review indicate that laparoscopic DP coupled with perioperative management influences outcome in DP patients. PMID:25805921

  13. Standard industry components as I\\/O extension for an Interlock System at PITZ, MTF and XFEL

    Microsoft Academic Search

    T. Grevsmuhl; M. Penno; M. Grimberg; L. Jachmann; W. Kohler; H. Leich; G. Trowitzsch; R. Wenndorff

    2009-01-01

    The main task of the interlock system is to prevent any damage of the costly components of the RF station. The implementation of the interlock must also guarantee a maximum uninterrupted time of operation which implies the implementation of self diagnostics and repair strategies on a modular basis. Additional tasks include collection and temporary storage of status information of individual

  14. Vertebral Artery Dissect Injury with Brown-Séquard Syndrome by a Neural Foramen Penetrated Electric Screw Driver Bit : A Case Report

    PubMed Central

    Oh, Chang Hyun; Kim, Min Soo; Noh, Sung Hyun; Ji, Gyu Yeul

    2013-01-01

    There are few reports in the literature of complete obstruction of the vertebral artery (VA) due to an electric screw driver bit penetration through the neural foramen into the spinal canal with Brown-Séquard syndrome (BSS). A 25-year-old man was admitted to the emergency department with a penetrated neck injury by an electric screw driver bit after a struggle. The patient presented the clinical features of BSS. Computed tomography scan revealed that the electric screw driver bit penetrated through the right neural foramen at the level of C3-4, and it caused an injury to the right half of the spinal cord. Emergent angiography revealed VA dissection, which was managed by immediate coil embolization at both proximal and distal ends of the injury site. After occlusion of the VA, the electric screw driver bit was extracted under general anesthesia. Bleeding was minimal and controlled without difficulties. No postoperative complications, such as wound dehiscence, CSF leakage, or infection, were noted. Endovascular approaches for occlusion of vertebral artery lesions are safe and effective methods of treatment. PMID:24891861

  15. 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. PMID:9158197

  16. Chicxulub Distal Ejecta: Modeling Versus Observations

    NASA Astrophysics Data System (ADS)

    Morgan, J. V.; Artemieva, N.

    We investigate the formation of the K-P layer through numerical modeling. A subset of our models replicate the observational data reasonably well, and suggest that non-ballistic ejection is required for shocked minerals to reach distal sites.

  17. Genetics Home Reference: Laing distal myopathy

    MedlinePLUS

    ... of type I fibers. In cardiac and skeletal muscle cells, the protein produced from the MYH7 gene forms ... autosomal dominant ; cardiac ; cell ; contraction ; distal ; gene ; inherited ; muscle cells ; muscular dystrophy ; mutation ; myosin ; prevalence ; protein ; sign ; skeletal ...

  18. Screw dislocations in GaN

    SciTech Connect

    Liliental-Weber, Zuzanna; Jasinski, Jacek B.; Washburn, Jack; O'Keefe, Michael A.

    2002-02-15

    GaN has received much attention over the past few years because of several new applications, including light emitting diodes, blue laser diodes and high-power microwave transistors. One of the biggest problems is a high density of structural defects, mostly dislocations, due to a lack of a suitable lattice-matched substrate since bulk GaN is difficult to grow in large sizes. Transmission Electron Microscopy (TEM) has been applied to study defects in plan-view and cross-sections on samples prepared by conventional techniques such as mechanical thinning and precision ion milling. The density of dislocations close to the sample surface of a 1 mm-thick HVPE sample was in the range of 3x109 cm-2. All three types of dislocations were present in these samples, and almost 50 percent were screw dislocations. Our studies suggest that the core structure of screw dislocations in the same material might differ when the material is grown by different methods.

  19. Distal forearm tourniquet for hand surgery

    Microsoft Academic Search

    Alberto D. Delgado-Martinez; J. M. Marchal; F. Blanco; M. Molina; A. Palma

    2004-01-01

    To evaluate the usefulness of the tourniquet placed at the distal forearm, 30 patients were operated with the tourniquet set at the distal forearm using nerve-block anaesthesia. Pain during surgery, flexion of the fingers, bloodless field, and general complications during surgery and 18 months thereafter were recorded. The mean time of ischemia was 19.6±7.5 (10–50) min. A bloodless field was achieved in

  20. Lateral Movement of Screw Dislocations During Homoepitaxial Growth and Devices Yielded Therefrom Free of the Detrimental Effects of Screw Dislocations

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G. (Inventor); Powell, J. Anthony (Inventor)

    2004-01-01

    The present invention is related to a method that enables and improves wide bandgap homoepitaxial layers to be grown on axis single crystal substrates, particularly SiC. The lateral positions of the screw dislocations in epitaxial layers are predetermined instead of random, which allows devices to be reproducibly patterned to avoid performance degrading crystal defects normally created by screw dislocations.

  1. Intraoperative C-arm CT imaging in angular stable plate osteosynthesis of distal radius fractures.

    PubMed

    Mehling, I; Rittstieg, P; Mehling, A P; Küchle, R; Müller, L P; Rommens, P M

    2013-09-01

    The purpose of this study was to analyze the practicability and benefit of intraoperative C-arm computed tomography (CT) imaging in volar plate osteosynthesis of unstable distal radius fractures. During a 1 year period, intraoperative three dimensional (3D) imaging with the ARCADIS Orbic 3D was performed in addition to standard fluoroscopy in 51 cases. The volar angular stable plate oesteosyntheses were analyzed intraoperatively and, if necessary, improved immediately. The duration of the scan and radiation exposure dose were measured. On average, performance of the scan and analysis of the CT dataset took 6.7 minutes. In 31.3% of the surgeries a misplacement of screws was detected and correction was done immediately. C-arm CT imaging can easily be integrated in the normal course of surgery. As a complement to the standard 2D-fluoroscopy, the C-arm CT is a useful tool to evaluate the quality of osteosynthesis. PMID:23390154

  2. Flexor tendon repair after rupture caused by volar plate fixation of the distal radius.

    PubMed

    Rubensson, Carin C; Ydreborg, Karin; Boren, Linda; Karlander, Lars-Erik

    2015-04-01

    Volar plate fixation of unstable fractures of the distal radius is preferred by a majority of surgeons today. One known complication is the rupture of flexor tendons. The aim of this paper is to present flexor tendon ruptures after volar plate fixation analysing the clinical outcome after tendon surgery, aetiology, and methods of prevention. Seventeen consecutive ruptures in 14 patients were included. The incidence was 1.4%. Three patients declined tendon surgery. Eleven patients were treated with a free tendon graft. Only two patients showed excellent results regarding mobility in the thumb and/or fingers. Analysis of radiographs demonstrated sub-optimal placement of plate or screws in all cases. Rupture of a flexor tendon is a serious complication where the functional outcome after surgical reconstruction is uncertain. Early removal of the plate when the placement is sub-optimal or when local volar tenderness appears would probably prevent many ruptures. PMID:25162925

  3. Salvaging the pullout strength of stripped screws in osteoporotic bone.

    PubMed

    Pechon, Pierre H M; Mears, Simon C; Langdale, Evan R; Belkoff, Stephen M

    2013-06-01

    Our goal was to determine whether the pullout strength of stripped screw holes in osteoporotic bone could be increased with readily available materials from the operating room. We inserted 3.5-mm stainless steel nonlocking self-tapping cortical screws bicortically into 5 osteoporotic humeri. Each screw was first stripped by rotating it 1 full turn past maximum torque. In the control group, the screw was pulled out using an MTS machine (858; MTS Inc, Eden Prairie, Minnesota). In the treatment groups, the screw was removed, the hole was augmented with 1 of the 3 materials (stainless steel wire, polysorb suture, or polyethylene terephthalate glycol plastic sheet), and the screws were replaced and then pulled out. The effect of material on pullout strength was checked for significance (P < .05) using a general linearized latent and mixed model (Stata10; StataCorp, College Station, Texas). The mean (95% confidence interval) pullout strength for the unaugmented hole was 138 N (range 88-189), whereas the holes augmented with plastic, suture, or wire had mean pullout strengths of 255 N (range 177-333), 228 N (range 149-308), and 396 N (range 244-548), respectively. Although wire augmentation resulted in pullout strength that was significantly greater than that of the unaugmented screw, it was still below that of the intact construct. PMID:24093076

  4. Salvaging the Pullout Strength of Stripped Screws in Osteoporotic Bone

    PubMed Central

    Pechon, Pierre H. M.; Mears, Simon C.; Langdale, Evan R.; Belkoff, Stephen M.

    2013-01-01

    Our goal was to determine whether the pullout strength of stripped screw holes in osteoporotic bone could be increased with readily available materials from the operating room. We inserted 3.5-mm stainless steel nonlocking self-tapping cortical screws bicortically into 5 osteoporotic humeri. Each screw was first stripped by rotating it 1 full turn past maximum torque. In the control group, the screw was pulled out using an MTS machine (858; MTS Inc, Eden Prairie, Minnesota). In the treatment groups, the screw was removed, the hole was augmented with 1 of the 3 materials (stainless steel wire, polysorb suture, or polyethylene terephthalate glycol plastic sheet), and the screws were replaced and then pulled out. The effect of material on pullout strength was checked for significance (P < .05) using a general linearized latent and mixed model (Stata10; StataCorp, College Station, Texas). The mean (95% confidence interval) pullout strength for the unaugmented hole was 138 N (range 88-189), whereas the holes augmented with plastic, suture, or wire had mean pullout strengths of 255 N (range 177-333), 228 N (range 149-308), and 396 N (range 244-548), respectively. Although wire augmentation resulted in pullout strength that was significantly greater than that of the unaugmented screw, it was still below that of the intact construct. PMID:24093076

  5. Small Worlds Among Interlocking Directors: Network Structure and Distance in Bipartite Graphs

    Microsoft Academic Search

    Garry Robins; Malcolm Alexander

    2004-01-01

    We describe a methodology to examine bipartite relational data structures as exemplified in networks of corpo- rate interlocking. These structures can be represented as bipartite graphs of directors and companies, but direct comparison of empirical datasets is often problematic because graphs have different numbers of nodes and dif- ferent densities. We compare empirical bipartite graphs to simulated random graph distributions

  6. Safety criteria for the vital processor interlocking at HoornKersenboogerd

    E-print Network

    Fokkink, Wan

    ­ Kersenboogerd, computer equipment based on a Vital Processor Interlock- ing (VPI) is used in order to ensure safe movement of trains. Apart from a number of hardware checks, a VPI essentially executes a program formula as follows. Each second, the VPI executes a control cycle, which starts with reading new values

  7. 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.

  8. Improved adhesion in hybrid Si-polymer MEMS via micromechanical interlocking

    Microsoft Academic Search

    M. P. Larsson; R. R. A. Syms; A. G. Wojcik

    2005-01-01

    A method for improving adhesion between polymer films on Si substrates is described involving mechanical interlocking. Isotropic reactive ion etching (RIE) is applied to form pits in the Si substrate which fill upon application of a polymer via spinning. After curing, interpenetrating polymer lobes form a robust bond with the Si substrate. Adhesion improvements over films on smooth substrates are

  9. 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...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...

  10. 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...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...

  11. 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...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...

  12. 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...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...

  13. 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...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...

  14. In-Situ Measurements of Interlocking Concrete Pavement Response to Vehicular Loading and Environment

    Microsoft Academic Search

    Sudip Adhikari; Susan Tighe; Robert Burak

    This paper presents an innovative research project involving the design, construction and instrumentation of seven interlocking concrete pavement (ICP) crosswalks. In total there are four different structural designs presented. These were constructed at the Centre for Pavement and Transportation Technology (CPATT) test track and at the University of Waterloo Ring Road in 2007 and will involve the development of mechanistic-empirical

  15. DESIGN PROCESS OF THE INTERLOCK SYSTEM FOR THE COMPACT LINEAR COLLIDER

    E-print Network

    Paris-Sud XI, Université de

    development process has brought the usage of a safety-system and systemic approach, resulting in a formalization of the lifecycle of a protection system [1]. The protection systems for the new generationsDESIGN PROCESS OF THE INTERLOCK SYSTEM FOR THE COMPACT LINEAR COLLIDER P. Nouvel1,2,3 , B. Puccio1

  16. DUI risk prediction with alcohol biomarkers, interlock records, and self-report

    Microsoft Academic Search

    Paul Marques; Martin Javors; Fritz Pragst; Volker Auwaerter; Steina Aradottir; Christer Alling; Michel Yegles; Friedrich Wurst

    2007-01-01

    The risk of impaired driving can be estimated through the use of several technologies but few programs utilize the full spectrum of predictive technologies and often underutilize the ones they do employ. The record of alcohol ignition interlock breath alcohol (BAC) tests are good predictors of future DUI risk, but still not widely used. These are a good, but imperfect

  17. 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.

  18. Patterns In Contingencies: The Interlocking of Formal and Informal Political Institutions in Contemporary Argentina

    ERIC Educational Resources Information Center

    Llamazares, Ivan

    2005-01-01

    This article explores how the interlocking of formal and informal political institutions has affected the dynamics and performance of the Argentine democracy. Key institutional features of the Argentine political system have been a competitive form of federalism, loosely structured and political parties that are not ideologically unified,…

  19. Dynamic-locking-screw (DLS)–leads to less secondary screw perforations in proximal humerus fractures

    PubMed Central

    2014-01-01

    Background Loss of reduction and screw perforation causes high failure rates in the treatment of proximal humerus fractures. The purpose of the present study was to evaluate the early postoperative complications using modern Dynamic Locking Screws (DLS 3.7) for plating of proximal humerus fractures. Methods Between 03/2009 and 12/2010, 64 patients with acute proximal humerus fractures were treated by angular stable plate fixation using DLSs in a limited multi-centre study. Follow-up examinations were performed three, six, twelve and twenty-four weeks postoperatively and any complications were carefully collected. Results 56 of 64 patients were examined at the six-month follow-up. Complications were observed in 12 patients (22%). In five cases (9%), a perforation of the DLS 3.7 occurred. Conclusions Despite the use of modern DLS 3.7, the early complications after plating of proximal humerus fractures remain high. The potential advantage of the DLS 3.7 regarding secondary screw perforation has to be confirmed by future randomized controlled trials. PMID:24894637

  20. Comparison of Expansive Pedicle Screw and Polymethylmethacrylate-Augmented Pedicle Screw in Osteoporotic Sheep Lumbar Vertebrae: Biomechanical and Interfacial Evaluations

    PubMed Central

    Zhang, Bo; Xie, Qing-yun; Wang, Cai-ru; Liu, Jin-biao; Liao, Dong-fa; Jiang, Kai; Lei, Wei; Pan, Xian-ming

    2013-01-01

    Background It was reported that expansive pedicle screw (EPS) and polymethylmethacrylate-augmented pedicle screw (PMMA-PS) could be used to increase screw stability in osteoporosis. However, there are no studies comparing the two kinds of screws in vivo. Thus, we aimed to compare biomechanical and interfacial performances of EPS and PMMA-PS in osteoporotic sheep spine. Methodology/Principal Findings After successful induction of osteoporotic sheep, lumbar vertebrae in each sheep were randomly divided into three groups. The conventional pedicle screw (CPS) was inserted directly into vertebrae in CPS group; PMMA was injected prior to insertion of CPS in PMMA-PS group; and the EPS was inserted in EPS group. Sheep were killed and biomechanical tests, micro-CT analysis and histological observation were performed at both 6 and 12 weeks post-operation. At 6-week and 12-week, screw stabilities in EPS and PMMA-PS groups were significantly higher than that in CPS group, but there were no significant differences between EPS and PMMA-PS groups at two study periods. The screw stability in EPS group at 12-week was significantly higher than that at 6-week. The bone trabeculae around the expanding anterior part of EPS were more and denser than that in CPS group at 6-week and 12-week. PMMA was found without any degradation and absorption forming non-biological “screw-PMMA-bone” interface in PMMA-PS group, however, more and more bone trabeculae surrounded anterior part of EPS improving local bone quality and formed biological “screw-bone” interface. Conclusions/Significance EPS can markedly enhance screw stability with a similar effect to the traditional method of screw augmentation with PMMA in initial surgery in osteoporosis. EPS can form better biological interface between screw and bone than PMMA-PS. In addition, EPS have no risk of thermal injury, leakage and compression caused by PMMA. We propose EPS has a great application potential in augmentation of screw stability in osteoporosis in clinic. PMID:24086381

  1. Hallux valgus in men: effect of the distal metatarsal articular angle on hallux valgus correction.

    PubMed

    Coughlin, M J

    1997-08-01

    The results of hallux valgus correction were reviewed for 34 male patients (41 feet). The severity of the preoperative deformity determined the operative technique of correction. A distal soft tissue procedure with proximal first metatarsal osteotomy was performed in 30 patients (35 feet) with an average correction of the hallux valgus angle of 22 degrees. A chevron procedure was performed in five cases and a McBride procedure in one other case, all with less severe deformities. Complications included one deep wound infection, one broken screw at the metatarsal osteotomy site, and three cases of hallux varus. No patients underwent reoperation. Undercorrection was noted in 10 of 35 cases (29%) where a distal soft tissue procedure with proximal first metatarsal osteotomy was performed. A nonsubluxated (congruent) metatarsophalangeal (MTP) joint associated with a hallux valgus deformity was present in 15 of 41 (37%) of all cases and 10 of 35 (29%) of cases that underwent a distal soft tissue procedure with proximal metatarsal osteotomy (DSTR with PMO). A subluxated (noncongruent) MTP joint associated with hallux valgus was present in 26 of 41 (63%) of all cases and 25 of 35 (71%) of cases undergoing a DSTR with PMO. There was a highly significant difference in the average distal metatarsal articular angle (DMAA) as measured in the nonsubluxated (congruent) MTP joints (20.7 degrees) and the subluxated (noncongruent) MTP joints with hallux valgus (10 degrees) (P = 0.0001). The average distal metatarsal articular angle for all cases undergoing DSTR with PMO was 13 degrees. When the postoperative hallux valgus angle was compared with DMAA, the average residual hallux valgus angle was 10.1 degrees. With a subluxated (noncongruent) first MTP joint with hallux valgus (a low DMAA), the percent of hallux valgus correction (hallux valgus correction [in degrees]/preoperative hallux valgus deformity [in degrees]) was 77%. In patients with a nonsubluxated (congruent) first MTP joint with hallux valgus (a high DMAA), the percent correction was 46%, an almost twofold difference in percent correction. There was a close correlation between the preoperative DMAA and the postoperative hallux valgus angle in both the subluxated and congruent subgroups (P = 0.0003). With an intra-articular repair (a DSTP with PMO), the magnitude of correction of a hallux valgus deformity is limited at the MTP joint by the distal metatarsal articular angle. PMID:9278739

  2. Helical screw rheometer: a new concept in rotational rheometry

    SciTech Connect

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

    1984-01-01

    The helical screw rheometer represents a new concept in viscometry: a rotational instrument that generates a pressure difference and therefore does not require torque measurement. The device is basically a metering screw that operates with no discharge. The results that are necessary to obtain the power-law constitutive parameters from pressure drop and rotation rate data are presented along with comparisons between theory and experiment for a prototype instrument operated at ambient conditions. The helical screw rheometer may offer advantages over conventional instruments for: 1) high-pressure measurements, 2) chemically-reacting fluids, 3) heterogeneous fluids and 4) on-line measurements.

  3. Analysis of Material Flow in Screw Extrusion of Aluminum

    SciTech Connect

    Haugen, Bjoern; Oernskar, Magnus; Welo, Torgeir; Wideroee, Fredrik [Department of Engineering Design and Materials, NTNU (Norway)

    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.

  4. Noninvasive method for retrieval of broken dental implant abutment screw.

    PubMed

    Gooty, Jagadish Reddy; Palakuru, Sunil Kumar; Guntakalla, Vikram Reddy; Nera, Mahipal

    2014-04-01

    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

  5. 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.

  6. Aquaporin-0 Targets Interlocking Domains to Control the Integrity and Transparency of the Eye Lens

    PubMed Central

    Lo, Woo-Kuen; Biswas, Sondip K.; Brako, Lawrence; Shiels, Alan; Gu, Sumin; Jiang, Jean X.

    2014-01-01

    Purpose. Lens fiber cell membranes contain aquaporin-0 (AQP0), which constitutes approximately 50% of the total fiber cell membrane proteins and has a dual function as a water channel protein and an adhesion molecule. Fiber cell membranes also develop an elaborate interlocking system that is required for maintaining structural order, stability, and lens transparency. Herein, we used an AQP0-deficient mouse model to investigate an unconventional adhesion role of AQP0 in maintaining a normal structure of lens interlocking protrusions. Methods. The loss of AQP0 in AQP0?/? lens fibers was verified by Western blot and immunofluorescence analyses. Changes in membrane surface structures of wild-type and AQP0?/? lenses at age 3 to 12 weeks were examined with scanning electron microscopy. Preferential distribution of AQP0 in wild-type fiber cell membranes was analyzed with immunofluorescence and immunogold labeling using freeze-fracturing transmission electron microscopy. Results. Interlocking protrusions in young differentiating fiber cells developed normally but showed minor abnormalities at approximately 50 ?m deep in the absence of AQP0 in all ages studied. Strikingly, protrusions in maturing fiber cells specifically underwent uncontrolled elongation, deformation, and fragmentation, while cells still retained their overall shape. Later in the process, these changes eventually resulted in fiber cell separation, breakdown, and cataract formation in the lens core. Immunolabeling at the light microscopy and transmission electron microscopy levels demonstrated that AQP0 was particularly enriched in interlocking protrusions in wild-type lenses. Conclusions. This study suggests that AQP0 exerts its primary adhesion or suppression role specifically to maintain the normal structure of interlocking protrusions that is critical to the integrity and transparency of the lens. PMID:24458158

  7. Complications After Open Distal Clavicle Excision

    PubMed Central

    Chronopoulos, Efstathis; Gill, Harpreet S.; Freehill, Michael T.; Petersen, Steve A.

    2008-01-01

    Isolated distal clavicle excision performed as an open procedure has been considered safe and, in the literature, has been considered the standard for comparison with arthroscopic distal clavicle excisions. However, we noticed isolated open distal clavicle excision was associated with a number of complications. We therefore raised two questions about the complication rate in a cohort of our patients who had undergone this procedure: (1) What was the complication rate and how did it compare to that in the existing literature on this subject? and (2) Were the complications in our cohort similar to those previously reported? We studied 42 patients who underwent an isolated distal clavicle excision between 1992 and 2003. There were 27 complications (64%), which was substantially higher than rates previously reported. Complications in our cohort not previously reported included continued acromioclavicular joint tenderness and scar hypertrophy. Our study suggests complications after open distal clavicle excisions may be more frequent than and may differ from previously reported rates and types. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18264853

  8. Outcome Following Acute Primary Distal Ulna Resection for Comminuted Distal Ulna Fractures at the Time of Operative Fixation of Unstable Fractures of the Distal Radius

    Microsoft Academic Search

    David E. Ruchelsman; Keith B. Raskin; Michael E. Rettig

    2009-01-01

    Optimal acute management of the highly comminuted distal ulna head\\/neck fracture sustained in conjunction with an unstable\\u000a distal radius fracture requiring operative fixation is not well established. The purpose of the present study was to determine\\u000a the clinical, radiographic, and functional outcomes following acute primary distal ulna resection for comminuted distal ulna\\u000a fractures performed in conjunction with the operative fixation

  9. Posterior spinal fusion for adolescent idiopathic thoracolumbar/lumbar scoliosis: clinical outcomes and predictive radiological factors for extension of fusion distal to caudal end vertebra.

    PubMed

    Roberts, S B; Tsirikos, A I; Subramanian, A S

    2014-08-01

    Clinical, radiological, and Scoliosis Research Society-22 questionnaire data were reviewed pre-operatively and two years post-operatively for patients with thoracolumbar/lumbar adolescent idiopathic scoliosis treated by posterior spinal fusion using a unilateral convex segmental pedicle screw technique. A total of 72 patients were included (67 female, 5 male; mean age at surgery 16.7 years (13 to 23)) and divided into groups: group 1 included 53 patients who underwent fusion between the vertebrae at the limit of the curve (proximal and distal end vertebrae); group 2 included 19 patients who underwent extension of the fusion distally beyond the caudal end vertebra. A mean scoliosis correction of 80% (45% to 100%) was achieved. The mean post-operative lowest instrumented vertebra angle, apical vertebra translation and trunk shift were less than in previous studies. A total of five pre-operative radiological parameters differed significantly between the groups and correlated with the extension of the fusion distally: the size of the thoracolumbar/lumbar curve, the lowest instrumented vertebra angle, apical vertebra translation, the Cobb angle on lumbar convex bending and the size of the compensatory thoracic curve. Regression analysis allowed an equation incorporating these parameters to be developed which had a positive predictive value of 81% in determining whether the lowest instrumented vertebra should be at the caudal end vertebra or one or two levels more distal. There were no differences in the Scoliosis Research Society-22 outcome scores between the two groups (p = 0.17). In conclusion, thoracolumbar/lumbar curves in patients with adolescent idiopathic scoliosis may be effectively treated by posterior spinal fusion using a unilateral segmental pedicle screw technique. Five radiological parameters correlate with the need for distal extension of the fusion, and an equation incorporating these parameters reliably informs selection of the lowest instrumented vertebra. PMID:25086125

  10. Recent advances in distal tubular potassium handling

    PubMed Central

    Rodan, Aylin R.; Cheng, Chih-Jen

    2011-01-01

    It is well known that sodium reabsorption and aldosterone play important roles in potassium secretion by the aldosterone-sensitive distal nephron. Sodium- and aldosterone-independent mechanisms also exist. This review focuses on some recent studies that provide novel insights into the sodium- and aldosterone-independent potassium secretion by the aldosterone-sensitive distal nephron. In addition, we discuss a study reporting on the regulation of the mammalian potassium kidney channel ROMK by intracellular and extracellular magnesium, which may be important in the pathogenesis of persistent hypokalemia in patients with concomitant potassium and magnesium deficiency. We also discuss outstanding questions and propose working models for future investigation. PMID:21270092

  11. Distal-Selective Hydroformylation using Scaffolding Catalysis

    PubMed Central

    2015-01-01

    In hydroformylation, phosphorus-based directing groups have been consistently successful at placing the aldehyde on the carbon proximal to the directing group. The design and synthesis of a novel catalytic directing group are reported that promotes aldehyde formation on the carbon distal relative to the directing functionality. This scaffolding ligand, which operates through a reversible covalent bond to the substrate, has been applied to the diastereoselective hydroformylation of homoallylic alcohols to afford ?-lactones selectively. Altering the distance between the alcohol and the olefin revealed that homoallylic alcohols gives the distal lactone with the highest levels of regioselectivity. PMID:24902624

  12. Distal-selective hydroformylation using scaffolding catalysis.

    PubMed

    Joe, Candice L; Blaisdell, Thomas P; Geoghan, Allison F; Tan, Kian L

    2014-06-18

    In hydroformylation, phosphorus-based directing groups have been consistently successful at placing the aldehyde on the carbon proximal to the directing group. The design and synthesis of a novel catalytic directing group are reported that promotes aldehyde formation on the carbon distal relative to the directing functionality. This scaffolding ligand, which operates through a reversible covalent bond to the substrate, has been applied to the diastereoselective hydroformylation of homoallylic alcohols to afford ?-lactones selectively. Altering the distance between the alcohol and the olefin revealed that homoallylic alcohols gives the distal lactone with the highest levels of regioselectivity. PMID:24902624

  13. 21 CFR 872.4880 - Intraosseous fixation screw or wire.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...4880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4880 Intraosseous fixation screw or wire. (a)...

  14. 21 CFR 872.4880 - Intraosseous fixation screw or wire.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...4880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4880 Intraosseous fixation screw or wire. (a)...

  15. A Screw -Theoretic Framework for Musculoskeletal System Modeling and Analysis

    E-print Network

    Krovi, Venkat

    A Screw -Theoretic Framework for Musculoskeletal System Modeling and Analysis by Michael J. Del of tools for musculoskeletal system analysis, leveraging methodologies which have revolutionized can model, simulate, and analyze a redundant musculoskeletal system with (i) an adequate degree

  16. Screw anchors economically control pipeline buoyancy in muskeg

    SciTech Connect

    Robertson, R.; Curle, R. [NOVA Gas Transmission Ltd., Calgary, Alberta (Canada)

    1995-04-24

    To control buoyancy of large-diameter pipelines that cross such wet areas as muskeg swamps in Alberta Province, Canada, NOVA Gas Transmission Ltd., Calgary, for more than 6 years investigated alternatives to traditional concrete weights. The company`s research indicated that helical screw anchors offer cost-effective buoyancy control for natural-gas pipelines 20-in. OD and larger. Muskegs are organic soils with high water tables, low shear strengths, and low densities (specific gravity of 1.04). NOVA`s experience demonstrated practical and cost benefits of screw anchors to resist uplift forces. And among other benefits, substitution of screw anchors for concrete weights significantly reduced the number of heavy trucks that must be moved across the muskeg. The paper discusses buoyancy control, pipeline adaptation, pipe stresses and corrosion, pipeline construction and screw-anchor installation, economics and other benefits.

  17. Wet-gas compression in twin-screw multiphase pumps 

    E-print Network

    Chan, Evan

    2009-05-15

    encountered when operating under conditions with high gas volume fractions (GVF). Twin-screw multiphase pumps experience a severe decrease in efficiency when operating under wet-gas conditions, GVF over 95%. Field operations have revealed severe vibration...

  18. Wet-gas compression in twin-screw multiphase pumps

    E-print Network

    Chan, Evan

    2009-05-15

    Multiphase pumping with twin-screw pumps is a relatively new technology that has been proven successful in a variety of field applications. By using these pumps to add energy to the combined gas and liquid wellstream with minimal separation...

  19. Screw-matrix method in dynamics of multibody systems

    NASA Astrophysics Data System (ADS)

    Yanzhu, Liu

    1988-05-01

    In the present paper the concept of screw in classical mechanics is expressed in matrix form, in order to formulate the dynamical equations of the multibody systems. The mentioned method can retain the advantages of the screw theory and avoid the shortcomings of the dual number notation. Combining the screw-matrix method with the tool of graph theory in Roberson/Wittenberg formalism. We can expand the application of the screw theory to the general case of multibody systems. For a tree system, the dynamical equations for each j-th subsystem, composed of all the outboard bodies connected by j-th joint can be formulated without the constraint reaction forces in the joints. For a nontree system, the dynamical equations of subsystems and the kinematical consistency conditions of the joints can be derived using the loop matrix. The whole process of calculation is unified in matrix form. A three-segment manipulator is discussed as an example.

  20. Numerical Synthesis of Overconstrained Mechanisms Based on Screw Theory

    Microsoft Academic Search

    René Bartkowiak; Christoph Woernle

    \\u000a An approach for the synthesis of overconstrained single-loop mechanisms with helical joints using screw theory is presented.\\u000a By expressing higher-order derivatives of the screw axes with respect to the joint coordinates a local approximation of the\\u000a closure conditions is obtained. The approximation is used to define conditions for the finite mobility of overconstrained\\u000a mechanisms.

  1. Design of Limb for Parallel Mechanism Based on Screw Theory

    Microsoft Academic Search

    Zhigang Lai; Lixin Li; Ping' an Liu

    2010-01-01

    \\u000a Based on the reciprocal relationship of twist and wrench in screw theory, the mathematical model for limb of parallel manipulator\\u000a is established in this paper. According to the motion modes of mobile platform (translation or rotation), we concluded the\\u000a geometric conditions which the prismatic joint or revolute joint must meet with by analyzing the constraint screw on the platform,\\u000a which

  2. Finite displacements of points, planes, and lines via screw theory

    Microsoft Academic Search

    I. A. Parkin

    1995-01-01

    Geometrical elements, namely point, directed plane, and directed line, are here taken in isolation from any rigid body to which they may belong. The available finite screws are fully determined for a general finite displacement of each element. Each screw carries a quasi-pitch, or “quatch”, that reduces to the commonly-accepted pitch when a displacement becomes infinitesimal. Each element-displacement has its

  3. Crystal geometry of screw dislocation glide in tungsten nanocrystals

    NASA Astrophysics Data System (ADS)

    Sadanov, E. V.

    2015-02-01

    A zigzag pattern of low-temperature dislocation glide occurring in tungsten nanocrystals in the intersecting planes {110} and {211}, which belong to the <111> crystallographic zone, has been revealed using field ion microscopy. It has been shown that cores of 1/2[111] screw dislocations are undissociated within the limits of the resolution of the field ion microscope. It has been found experimentally that surface atoms are displaced into metastable positions in the region of the trace of screw dislocation motion.

  4. Long-term stability of angle-stable versus conventional locked intramedullary nails in distal tibia fractures

    PubMed Central

    2013-01-01

    Background In the last years intramedullary nailing has become the treatment of choice for most displaced diaphyseal tibia fractures. In contrast intramedullary nailing of distal tibia fractures is accompanied by problems like decreased biomechanical stability. Nevertheless the indications for intramedullary nailing have been extended to include even more distal fractures. The purpose of this study was to compare long-term mechanical characteristics of angle-stable versus conventional locked intramedullary nails in the treatment of unstable distal tibia fractures. Therefore, the effect of time on the mechanical properties of biodegradable sleeves was assessed. Methods 8 pairs of fresh, frozen porcine tibiae were used. The expert tibial nail (Synthes) was equipped with either three conventional locking screws (CL) or the angle-stable locking system (AS), consisting of a special ASLS screw and a biodegradable sleeve. Biomechanical testing included torsional and axial loading at different time-points over 12 weeks. Results The AS group showed a significantly higher torsional stiffness at all time-points (at least 60%) compared to the CL group (p??0.05). For axial stiffness and range of motion significant differences were found in the AS group. Conclusions The angle-stable locking system (ASLS) with the biodegradable sleeve provides significantly higher long-term stability. Especially the differences determined under torsional loading in this study may have clinical relevance. The ASLS permits the potential to decrease complications like secondary loss of reduction and mal-/non-union. PMID:23425016

  5. Cervical screw missing secondary to delayed esophageal fistula: case report.

    PubMed

    Cagli, Sedat; Isik, H Serdar; Zileli, Mehmet

    2009-10-01

    Although anterior surgical approaches to the cervical spine have become popular and safe in recent years, they also have some complications. We present a case of loss of an anterior cervical plate screw by the natural tracts. The patient was a 47- year-old woman who was operated on for cervical spondylotic myelopathy at another institution. Surgical interference included two levels of anterior discectomy, iliac graft placement and fixation using plate and screws. Two years later, plate dislocation and partial migration of the upper screws were observed. After 7 years the patient complained of dysphagia and she accepted removal of the osteosynthesis. Radiographical examination showed that one of the upper screws was missing and two lower screws were broken. Esophageal perforation was found during the surgery and repaired. Further progress was favourable. Complications associated with esophageal perforation may range from massive infection and death to spontaneous recovery. Erosion of the esophageal wall due to extruded bulky constructs may lead to a persistent fistula, abscess or septic diffusion. Spontaneous perforation of the esophagus and screw loss via the gastrointestinal tract make this case interesting.. PMID:19847769

  6. Backflow in twin-screw-type multiphase pump

    SciTech Connect

    Egashira, Kazuyuki; Shoda, Shinji; Tochikawa, Tetsuro [Japan National Oil Corp., Chiba (Japan); Furukawa, Akinori [Kyushu Univ. (Japan)

    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.

  7. Comparison of straight median sternotomy and interlocking sternotomy with respect to biomechanical stability

    PubMed Central

    Küçükdurmaz, Fatih; A??r, ?smail; Bezer, Murat

    2013-01-01

    AIM: To increase the stability of sternotomy and so decrease the complications because of instability. METHODS: Tests were performed on 20 fresh sheep sterna which were isolated from the sterno-costal joints of the ribs. Median straight and interlocking sternotomies were performed on 10 sterna each, set as groups 1 and 2, respectively. Both sternotomies were performed with an oscillating saw and closed at three points with a No. 5 straight stainless-steel wiring. Fatigue testing was performed in cranio-caudal, anterio-posterior (AP) and lateral directions by a computerized materials-testing machine cycling between loads of 0 to 400 N per 5 s (0.2 Hz). The amount of displacement in AP, lateral and cranio-caudal directions were measured and also the opposing bone surface at the osteotomy areas were calculated at the two halves of sternum. RESULTS: The mean displacement in cranio-caudal direction was 9.66 ± 3.34 mm for median sternotomy and was 1.26 ± 0.97 mm for interlocking sternotomy, P < 0.001. The mean displacement in AP direction was 9.12 ± 2.74 mm for median sternotomy and was 1.20 ± 0.55 mm for interlocking sternotomy, P < 0.001. The mean displacement in lateral direction was 8.95 ± 3.86 mm for median sternotomy and was 7.24 ± 2.43 mm for interlocking sternotomy, P > 0.001. The mean surface area was 10.40 ± 0.49 cm² for median sternotomy and was 16.8 ± 0.78 cm² for interlocking sternotomy, P < 0.001. The displacement in AP and cranio-caudal directions is less in group 2 and it is statistically significant. Displacement in lateral direction in group 2 is less but it is statistically not significant. Surface area in group 2 is significantly wider than group 1. CONCLUSION: Our test results demonstrated improved primary stability and wider opposing bone surfaces in interlocking sternotomy compared to median sternotomy. This method may provide better healing and less complication rates in clinical setting, further studies are necessary for its clinical implications. PMID:23878782

  8. Distal Radius Fractures: Choice of Treatment Procedures

    Microsoft Academic Search

    S. Pechlaner

    2003-01-01

    Summary BACKGROUND: Distal radius fractures are no longer injuries typical of elderly patients with osteoporosis. Driving at high speed and high-speed sports activities are responsible for causing such injuries in an increasing number of younger people. Although the kind of fracture suffered, bone density, and personal needs and requirements of patients demand an individualized treatment concept, a surgical approach for

  9. Current status of laparoscopic distal pancreatectomy.

    PubMed

    Rosales-Velderrain, A; Stauffer, J A; Bowers, S P; Asbun, H J

    2012-09-01

    Distal pancreatectomy is the therapeutic option of choice for patients with a benign or malignant lesion located in the body and/or tail of the pancreas when surgical intervention is indicated. With recent advances in and wide spread use of imaging studies, lesions of the pancreas are being diagnosed more commonly and it is likely that this will translate into an increased number of patients undergoing surgical resection. The laparoscopic approach to pancreatic resections has not been adopted as rapidly as it has for most other general surgical procedures. This is despite the fact that the current literature appears to validate laparoscopy as an acceptable and safe approach for distal pancreatectomy in patients with benign lesions, and has demonstrated the known benefits inherent to the laparoscopic technique. These benefits include lower intraoperative blood loss, less pain and analgesic requirements, earlier return of bowel function, and shorter recovery and hospital stay. Yet controversy still exists for the role of laparoscopy in the resection of malignant lesions. Recent reports however, have shown that laparoscopic distal pancreatectomy can safely be performed in known malignancies and, most importantly, after a laparoscopic oncological resection, the oncological benchmarks that have been related to survival, (such as negative surgical margins and number of peripancreatic lymph nodes resected), can also be accomplished. We sought to review the current literature on distal pancreatectomy, specifically the indications, laparoscopic approaches, splenectomy and spleen-preserving techniques, intraoperative and short-term outcomes, morbidity, mortality and oncological outcomes. PMID:22971634

  10. Interlocking Cross-Laminatd Timber (ICLT) for Rural Architecture Ryan E. Smith & Jeff Cramer, ITAC, University of Utah

    E-print Network

    Tipple, Brett

    - Department of Agriculture, Forest Products Laboratory University of Utah, Technology, University of Idaho, Wood Engineering Sam Glass, Forest Products Laboratory, WoodInterlocking Cross-Laminatd Timber (ICLT) for Rural Architecture Ryan E. Smith

  11. 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.

  12. Mid- to long-term clinical findings in nailing of distal femoral fractures.

    PubMed

    Funovics, Philipp T; Vécsei, Vilmos; Wozasek, Gerald E

    2003-01-01

    The purpose of the study was to evaluate clinical long-term results after nailing of distal femoral fractures. The first 22 consecutive cases of distal femoral fractures in 22 patients (2 males and 20 females, age 65 years, range, 16-97 years) treated with retrograde femoral nailing from October 1994 to May 1997 are reported. Indications were AO 33 A1 (n = 7), 33 A2 (n = 2), 33 A3 (n = 3), and 33 C2 (n = 7) fractures. In 11 cases these were periprosthetic fractures of either total hip arthroplasty or hemiarthroplasty of the hip (five) or dynamic hip screw (six), four patients were polytraumatized, one patient had a floating-knee injury. No infections or thrombosis were observed postoperatively. In 17 cases primary union was achieved within 11 weeks (8-17 weeks); five patients died before consolidation. Patients returned to full weightbearing after 5 weeks (4-12 weeks); active knee motion ranged from 80 degrees to 130 degrees. In five patients slight malalignment < 10 degrees was radiographically assessed, with two showing incipient degenerative joint disease. Patients younger than 60 years returned to full preoperative activity level. Eleven patients surviving an average of 5.2 years (4.3-6.9 years) were available for long-term follow-up. As a subgroup they were evaluated according to the Leung score for distal femoral fractures with seven excellent and four good results and an average score of 84.3 points (70-92 points). The mid- to long-term results confirm retrograde femoral nailing to be a good alternative to plate osteosynthesis for AO 33 A- and C2-type fractures. In young patients (< 60 years) postoperative clinical performance was highly satisfying; however, the effects of postoperative hemarthros and anatomic malalignment on the cartilage surface remain major issues for further investigation. PMID:15008286

  13. Self-tapping versus standard tapped titanium screw fixation in the upper extremity.

    PubMed

    Bickley, M B; Hanel, D P

    1998-03-01

    Most screws used in fracture fixation necessitate a separate step for tapping of the screw hole. Titanium screw systems have been developed in which the screws can be inserted directly after a drill hole is made. These self-tapping screws thereby eliminate an operative step. A retrospective study was conducted that evaluated all wrist and hand procedures performed between January 1992 and December 1994 by 1 surgeon using screw fixation. The results of 39 cases treated with standard tapped titanium screws were compared with 28 cases treated with self-tapping titanium screws. Nearly identical union and complication rates were obtained in each group. Comparable results can be obtained with self-tapping screw fixation, which limits the number of instruments needed, eliminates an operative step, and thereby may diminish operative risk and shorten operative time. PMID:9556274

  14. Anatomical study of axis for odontoid screw thickness, length, and angle

    PubMed Central

    Tun, Kagan; Cemil, Berker; Yorubulut, Mehmet; Karahan, S. Tuna; Tekdemir, Ibrahim

    2008-01-01

    Anterior odontoid screw fixation is a safe and effective method for treatment of odontoid fractures. The screw treads should fit into the odontoid medulla, should pass the fracture line, and should pull fractured odontoid tip against body of axis in order to achieve optimum screw placement and treatment. This study has demonstrated optimal anterior odontoid screw thickness, length, and optimal angle for safe and strong anterior odontoid screw placement. Dry bone axis vertebrae were evaluated by direct measurements, X-ray measurements, and computerized tomography (CT) measurements. The screw thickness (inner diameter of the odontoid) was measured as well as screw length (distance between anterior-inferior point body of axis and tip of odontoid), and screw angle (the angle between basis of axis and tip of odontoid). The inner diameter of odontoid bone was measured as 6.5 ± 1.9 mm, the screw length was 37.6 ± 3.3 mm, and the screw angle was 62.4 ± 4.7 on CT. There was no statistical difference between X-ray and CT in the measurements of screw thickness and angle. X-ray and CT measurements are both safe methods to determine the inner odontoid diameter and angle preoperatively. Screw length should be measured on CT only. To provide safe and strong anterior odontoid screw fixation, screw thickness, length, and angle should be known preoperatively, and these can be measured on X-ray and CT. PMID:19005694

  15. Interlocked feedforward loops control cell type-specific Rhodopsin expression in the Drosophila eye

    PubMed Central

    Johnston, Robert J.; Otake, Yoshiaki; Sood, Pranidhi; Vogt, Nina; Behnia, Rudy; Vasiliauskas, Daniel; McDonald, Elizabeth; Xie, Baotong; Koenig, Sebastian; Wolf, Reinhard; Cook, Tiffany; Gebelein, Brian; Kussell, Edo; Nagakoshi, Hideki; Desplan, Claude

    2011-01-01

    How complex networks of activators and repressors lead to exquisitely specific cell type determination during development is poorly understood. In the Drosophila eye, expression patterns of Rhodopsins define at least eight functionally distinct though related subtypes of photoreceptors. Here, we describe a role for the transcription factor gene defective proventriculus (dve) as a critical node in the network regulating Rhodopsin expression. dve is a shared component of two opposing, interlocked feedforward loops (FFLs). Orthodenticle and Dve interact in an incoherent FFL to repress Rhodopsin expression throughout the eye. In the R7 and R8 photoreceptors, a coherent FFL relieves repression by Dve while activating Rhodopsin expression. Therefore, this network uses repression to restrict, and combinatorial activation to induce cell type-specific expression. Further, Dve levels are finely tuned to yield cell type- and region-specific repression or activation outcomes. This interlocked FFL motif may be a general mechanism to control terminal cell fate specification. PMID:21663797

  16. Design lessons from using programmable controllers in the MFTF-B personnel safety and interlocks system

    SciTech Connect

    Branum, J.D.

    1983-11-29

    Applying programmable controllers in critical applications such as personnel safety and interlocks systems requires special considerations in the design of both hardware and software. All modern programmable controller systems feature extensive internal diagnostic capabilities to protect against problems such as program memory errors; however most, if not all present designs lack an intrinsic capability for detecting and countering failures on the field-side of their I/O modules. Many of the most common styles of I/O modules can also introduce potentially dangerous sneak circuits, even without component failure. This paper presents the most significant lessons learned to date in the design of the MFTF-B Personnel Safety and Interlocks System, which utilizes two non-redundant programmable controllers with over 800 I/O points each. Specific problems recognized during the design process as well as those discovered during initial testing and operation are discussed along with their specific solutions in hardware and software.

  17. Is distal locking of long nails for intertrochanteric fractures necessary? A clinical study

    PubMed Central

    Vopat, Bryan G.; Kane, Patrick M.; Truntzer, Jeremy; McClure, Philip; Paller, David; Abbood, Emily; Born, Christopher

    2014-01-01

    Background Few clinical studies have examined the utility of distal interlocking nails when fixing intertrochanteric fractures with intramedullary devices. In this study we performed a retrospective analysis comparing fixation method of intertrochanteric fractures with either a long unlocked cephalomedullary nail versus a long locked cephalomedullary nail. Our hypothesis was there would be no difference in device related failures or complications in stable intertrochanteric fractures treated with long locked or long unlocked cephalomedullary nails. Methods A retrospective chart review was performed of all stable intertrochanteric fractures treated with a long cephalomedullary nail between 2006 and 2012 at our institution. Clinical history as well as perioperative radiography was carefully reviewed for all subjects. AO classification, the use of locked or unlocked technique, and failure status was recorded. Results Overall, a device related failure rate of 1.8% (2/107) was observed for stable intertrochanteric fractures treated with long cephalomedullary nails. No statistical difference in failure rate was found between locked and unlocked nails within our studied population (0% long locked (0/56) versus 3.9% long unlocked (2/51), p = 0.224). Conclusion This clinical study supports our hypothesis that long cephalomedullary nails do not need to be locked for stable intertrochanteric fractures. We found no difference in failure rates between the two approaches across 107 patients. PMID:25983504

  18. VDHL DESIGN AND SIMULATION OF A FAST BEAM LOSS INTERLOCK FOR TTF2

    Microsoft Academic Search

    A. Hamdi; M. Luong; France M. Werner

    2004-01-01

    The TTF2 fast beam loss interlock provides different modes of protection. Based on the differential beam charge monitoring over a macropulse, a pulse slice or bunch-by-bunch, the signal processing time should be as short as the bunch repetition period (110 ns). The signal delivered by the toroid-like inductive current transformer always shows an envelope droop due to its self- inductance

  19. 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.

  20. Continuous non-invasive blood pressure monitoring using concentrically interlocking control loops

    Microsoft Academic Search

    J. Fortin; W. Marte; R. Grüllenberger; A. Hacker; W. Habenbacher; A. Heller; C. H. Wagner; P. Wach; F. Skrabal

    2006-01-01

    A new method and apparatus for non-disruptive blood pressure (BP) recording in the finger based on the vascular unloading technique is introduced. The instrument, in contrast to intermittent set point readjustments of the conventional vascular unloading technique, delivers BP without interruptions, thus refining the Pe?áz’ principle. The method is based on concentrically interlocking control loops for correct long-term tracing of

  1. 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).

  2. [Pseudarthroses after distal radius fractures. What is the role of the distal radioulnar joint?].

    PubMed

    Prommersberger, K J; van Schoonhoven, J; Laubach, S

    2000-11-01

    Non-union following distal radial fracture is extremely rare. Therefore, the patterns are not completely understood. Recently, it was suggested that an associated distal ulna shaft fracture increases the risk to develop a non-union for comminuted fractures of the distal radius. The purpose of this study was to review our 15 cases with this condition to investigate the role of an associated distal ulna shaft fracture and/or an associated lesion of the distal radioulnar joint. The second goal was to evaluate the success of the surgical treatment in relation to the extent of the metaphyseal subchondral bone supporting the articular surface distal to the site of the non-union. We reviewed our 15 cases which were operated on for non-union of the distal radius since 1992. In all cases, the radiographs could be reviewed. Twelve patients could actually be re-examined. The investigated criteria were: initial, pre- and postoperative X-ray findings, other medical conditions, range of motion, grip strength, and pain relief. Clinical outcome was evaluated using the DASH-questionnaire. According to the AO classification system, there were two type A3 and 13 type C3 fractures. There were seven associated distal ulna fractures. The distal radioulnar joint was involved in twelve cases. The other medical conditions in the patients with non-union after distal radial fracture included allergy, hypothyroidism, diabetes mellitus, peripheral neuropathy, and bronchial asthma. Four patients were tobacco smokers. Only one patient was initially treated non-operatively. In all cases, the distal radius was restored preserving wrist motion. Bony union was achieved in 14 cases. The range of motion has improved in all planes. Grip strength increased but still remained over 50% below the level of the opposite side. Postoperatively, the majority of patients was pain free. In four cases, complications were seen postoperatively. Three of these patients had less than 6 mm of metaphyseal subchondral bone beneath the articular surface. Three of the four patients were tobacco smokers. Inadequate treatment of a comminuted distal radial fracture associated with a special local situation--such as an additional distal ulna shaft fracture and/or an associated lesion of the distal radioulnar joint--combined with a general medical condition, adversely affects fracture healing, increasing the risk for non-union. From the review of the records of these 15 cases, we recommend that non-union with more than 5 mm of subchondral bone supporting the articular surface distal to the non-union site undergo reconstruction of the radius. Non-union with less than 5 mm subchondral bone supporting the articular surface requires an individual decision. A good bone stock and stable fixation allows for reconstruction of the radius, otherwise wrist fusion is a useful salvage procedure. PMID:11189891

  3. Carpal Canal Pressures after Volar Plating of Distal Radius Fractures

    Microsoft Academic Search

    D. A. FULLER; M. BARRETT; R. K. MARBURGER; R. HIRSCH

    2006-01-01

    Elevated pressures within the carpal canal are known to occur after distal radius fractures. Controversy exists regarding prophylactic carpal tunnel release after open reduction with internal fixation of distal radius fractures. The purpose of this study was to determine the tissue pressures within the carpal canal after volar plating of distal radius fractures. This study was a prospective, observational, IRB

  4. Early active rehabilitation for operatively stabilized distal radius fractures

    Microsoft Academic Search

    Mark H Henry; K BROU

    2004-01-01

    From the young to the elderly, distal radius fractures are very common. Extensive literature has been written regarding surgical management of distal radius fractures, but the same degree of attention has not been given to the critical rehabilitation that follows. Successful functional outcomes for distal radius fractures are a result of appropriate surgical treatment as well as timely and specific

  5. Locking screw apparatus and method for underwater remote replacement

    SciTech Connect

    Balog, L.J.

    1987-07-28

    A method is described for locking in place a screw which secures together first and second structures in the internal region of a nuclear reactor core. The first structure has a screw bore with a counterbore portion formed in an outer surface. The method comprises the steps of: forming a lateral recess in the counterbore portion and spaced from the outer surface, providing an elongated screw having an enlarged shoulder flange and an angular drive head with a lateral width substantially less than that of the counterbore portion, disposing the screw through the screw bore in threaded engagement with the second structure and with the shoulder rotatably seated in the counterbore portion. This provides a locking member having an angular opening and disposing it in the counterbore portion against the flange with the drive head received in the opening for engagement with the locking member to prevent rotation. This deforms a portion of the locking member into the recess for engagement to prevent movement of the locking member with respect to the first structure.

  6. The Epidemiology of Distal Radius Fractures

    PubMed Central

    Nellans, Kate W.; Kowalski, Evan; Chung, Kevin C.

    2012-01-01

    Distal radius fractures are one of the most common types of fractures, accounting for around 25% of fractures in the pediatric population and up to 18% of all fractures in the elderly age group. Although the pediatric and elderly populations are at the greatest risk for this injury, distal radius fractures still have a significant impact on the health and well-being of young adults. Data from the past 40 years has documented a trend towards an overall increase in the prevalence of this injury. For the pediatric population, this increase can likely be attributed to a surge in sports related activities. The growth of the elderly population and a rise in the number of active elderly are directly responsible for the increase seen in this age group. Understanding the epidemiology of this fracture is an important step towards the improvement of the treatment strategies and preventative measures which target this debilitating injury. PMID:22554654

  7. Aerotactile Integration from Distal Skin Stimuli

    PubMed Central

    Derrick, Donald; Gick, Bryan

    2015-01-01

    Tactile sensations at extreme distal body locations can integrate with auditory information to alter speech perception among uninformed and untrained listeners. Inaudible air puffs were applied to participants' ankles, simultaneously with audible syllables having aspirated and unaspirated stop onsets. Syllables heard simultaneously with air puffs were more likely to be heard as aspirated. These results demonstrate that event-appropriate information from distal parts of the body integrates in speech perception, even without frequent or robust location-specific experience. In addition, overall performance was significantly better for those with hair on their ankles, which suggests that the presence of hair may help establish signal relevance, and so aid in multi-modal speech perception. PMID:24649526

  8. Laparoscopic distal pancreatosplenectomy for pancreatic ductal adenocarcinoma.

    PubMed

    Kuroki, Tamotsu; Eguchi, Susumu

    2014-08-26

    Laparoscopic distal pancreatectomy (LDP) including laparoscopic distal pancreatosplenectomy has rapidly developed as a minimally invasive surgery. LDP is mainly indicated for benign disease and low-grade malignancy during the initial period. In recent years, an increasing number of LDPs for pancreatic ductal adenocarcinoma (PDAC) have been reported. However, the benefits of LPD for PDAC, especially in view of the oncological benefits, are unclear and remain controversial. In this review of the literature, we note that LDP has been found to be a technically feasible and safe surgical procedure in selected patients and that LDP has the advantages expected of a minimally invasive surgery. In addition, LDP has oncological feasibility for PDAC in light of its favorable rate of R0 resection and lymph node harvest compared to conventional laparotomy. Large randomized and controlled prospective studies are needed to determine the clinical advantages of LDP for left-sided PDAC. PMID:25156008

  9. 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. PMID:23942433

  10. Surgical approaches to the distal radius

    Microsoft Academic Search

    Asif M. Ilyas

    2011-01-01

    Introduction  Fractures of the distal radius are among the most common fractures seen. They encompass a myriad of presentations and fracture\\u000a patterns that often benefit from various open reduction and internal fixation techniques—including volar plating, dorsal plating,\\u000a radial plating, intramedullary nailing, and fragment-specific fixation. In order to obtain optimal reduction of these fractures,\\u000a surgeons require a thorough understanding of the anatomy

  11. 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

  12. Distal Embolic Protection for Renal Arterial Interventions

    SciTech Connect

    Dubel, Gregory J., E-mail: gdubel@lifespan.org; Murphy, Timothy P. [Brown University Medical School, Department of Diagnostic Imaging, Division of Interventional Radiology (United States)

    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.

  13. Distally based dorsal forearm fasciosubcutaneous flap.

    PubMed

    Kim, Kwang Seog

    2004-08-01

    Use of a local flap is often required for the reconstruction of a skin defect on the dorsum of the hand. For this purpose, a distally based dorsal forearm fasciosubcutaneous flap based on the perforators of the posterior interosseous artery was developed. From 1997 until 2002, this flap was used to reconstruct skin defects on the dorsum of the hand in nine patients at Chonnam National University Medical School. The sizes of these flaps ranged from 10 to 14 cm in length and from 5 to 7 cm in width. The flaps survived in all patients. Marginal loss over the distal edge of the flap was noted in one patient. Three flaps that developed minimal skin-graft loss were treated successfully with a subsequent split-thickness skin graft. The long-term follow-up showed good flap durability and elasticity. The distally based dorsal forearm fasciosubcutaneous flap is a convenient and reliable alternative for reconstructing skin defects of the dorsum of the hand involving vital structure exposure. It obviates the need for more complicated and time-consuming procedures. PMID:15277804

  14. Dynamics of free, straight dislocation pairs. I. Screw dislocations

    SciTech Connect

    Eykholt, R.; Trugman, S.A.; Srolovitz, D.J.

    1989-06-01

    Analytic expressions are derived for the motion of a pair of interacting, straight, parallel (or antiparallel) screw dislocations in an applied stress field. Analysis of the equations of motion of the dislocations shows that, under most circumstances, the velocity of a dislocation is proportional to the driving force (i.e., the motion is overdamped), and, in this limit, the results are exact. However, when the two dislocations are very close together, inertial terms begin to play a role, and the resultant ''finite-mass'' corrections are treated perturbatively. For the case of antiparallel screw dislocations, a capture cross section exists and is given by the product of the shear modulus and the Burgers vector over the applied stress. Based on these results, a simple statistical analysis of the motion of a large number of screw dislocations is presented.

  15. CMM probe compensation methods for measuring complex screw surface

    NASA Astrophysics Data System (ADS)

    Zhao, Qiancheng; Yang, Tianlong; Yin, Xiyun

    2013-01-01

    At present, probe compensation is the key problem in measuring geometric parameters of complex screw surface with CMM due to its complicated 3D shape, aiming at this problem, some new measurement methods are proposed based on geometric feature models, expressing the screw surface and its offset surface separately. Supposing the parameter lead of a screw surface is known, it's realized by scanning one single profile to complete probe compensation and calculate out all parameters, and the probe compensation is done by two improved methods, named as modified cross product and offset surface virtual measurement respectively, the theory and detailed process of which are discussed in this paper. After performing systematic experiments of profile scan, probe compensation and error evaluation, results show that the new measurement methods provide higher precision, stability and realizability.

  16. 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. PMID:21643076

  17. Tunable helium bubble superlattice ordered by screw dislocation network

    NASA Astrophysics Data System (ADS)

    di, Zengfeng; Bai, Xian-Ming; Wei, Qiangmin; Won, Jonghan; Hoagland, Richard G.; Wang, Yongqiang; Misra, Amit; Uberuaga, Blas P.; Nastasi, Michael

    2011-08-01

    Helium bubble nucleation at low-angle twist boundaries in gold has been investigated. It is found that the helium bubbles preferentially nucleate at screw dislocation nodal points and result in helium bubble superlattice formation, which is completely isomorphic with the screw dislocation network along the twist-grain boundary. Molecular statics calculations reveal that defect formation/solution energies along the screw dislocations, especially at the nodal points, are lower than their bulk counterparts. It is believed that this driving force is responsible for the helium bubble superlattice formation. Our study suggests that grain boundary engineering via adjustable twist angles in parallel boundaries to form tunable 3D bubble superlattices could afford a very promising approach for design of radiation tolerant materials.

  18. Simple technique for removing broken pedicular screw with plain and serviceable screwdriver

    Microsoft Academic Search

    Ahmet H. Kaya; Adnan Dagcinar; Fahrettin Celik; Alparslan Senel

    2008-01-01

    Removing the broken pedicular screw after spinal hardware failure is usually problematic. A specially designed simple screwdriver\\u000a and easy removal technique of broken pedicular screw with this screwdriver are described in this article.

  19. 29 CFR 1926.305 - Jacks-lever and ratchet, screw, and hydraulic.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Jacks-lever and ratchet, screw, and hydraulic. 1926.305 Section 1926.305...Jacks—lever and ratchet, screw, and hydraulic. (a) General requirements. ...otherwise secured at once. (ii) Hydraulic jacks exposed to freezing...

  20. Biomechanical and Histological Evaluation of Roughened Surface Titanium Screws Fabricated by Electron Beam Melting

    PubMed Central

    Yang, Jun; Cai, Hong; Lv, Jia; Zhang, Ke; Leng, Huijie; Wang, Zhiguo; Liu, Zhongjun

    2014-01-01

    Background Various fabrication methods are used to improve the stability and osseointegration of screws within the host bone. The aim of this study was to investigate whether roughened surface titanium screws fabricated by electron beam melting can provide better stability and osseointegration as compared with smooth titanium screws in sheep cervical vertebrae. Methods Roughened surface titanium screws, fabricated by electron beam melting, and conventional smooth surface titanium screws were implanted into sheep for 6 or 12 weeks (groups A and B, respectively). Bone ingrowth and implant stability were assessed with three-dimensional imaging and reconstruction, as well as histological and biomechanical tests. Results No screws in either group showed signs of loosening. Fibrous tissue formation could be seen around the screws at 6 weeks, which was replaced with bone at 12 weeks. Bone volume/total volume, bone surface area/bone volume, and the trabecular number were significantly higher for a define region of interest surrounding the roughened screws than that surrounding the smooth screws at 12 weeks. Indeed, for roughened screws, trabecular number was significantly higher at 12 weeks than at 6 weeks. On mechanical testing, the maximum pullout strength was significantly higher at 12 weeks than at 6 weeks, as expected; however, no significant differences were found between smooth and roughened screws at either time point. The maximum torque to extract the roughened screws was higher than that required for the smooth screws. Conclusions Electron beam melting is a simple and effective method for producing a roughened surface on titanium screws. After 12 weeks, roughened titanium screws demonstrated a high degree of osseointegration and increased torsional resistance to extraction over smooth titanium screws. PMID:24788866

  1. Biodegradation of Inion fast-absorbing biodegradable plates and screws.

    PubMed

    Losken, H Wolfgang; van Aalst, John A; Mooney, Mark P; Godfrey, Virginia L; Burt, Tripti; Teotia, Sumeet; Dean, Shay B; Moss, Jonathan R; Rahbar, Reza

    2008-05-01

    Biodegradable plates and screws are recommended for use in surgery of the craniofacial skeleton of children. To be effective and not interfere with growth of the child's skull, the plates must biodegrade sufficiently to release the holding power of the plate and screw within 1 year. It is also essential that excessive foreign body reaction and cyst formation does not occur when the plates and screws biodegrade. The purpose of this experimental study was to evaluate the rate of biodegradation of Inion CPS Baby biodegradable plates and screws under different clinical circumstances in the rabbit craniofacial skeleton and evaluate their efficacy for use in pediatric craniofacial surgery. Foreign body reaction would be evaluated. Inion baby plates and screws were tested in a rabbit model. Plates were applied to the frontal bone, over a bony defect of the parietal bone, to a nasal bone fracture, and inserted in the subcutaneous space over the occipital bone in thirty 6-week-old rabbits. Six rabbits were euthanized at 9, 12, 15, and 18 months' postoperative time point and examined for residual plates and screws. Bone from each surgical site was excised, fixed by immersion in 10% neutral-buffered formalin, decalcified in Immunocal solution, and examined by 7-microm paraffin sections stained with hematoxylin and eosin. At 9 months, the plates and screws had effectively biodegraded and no longer had holding power on the bones. Fragmentation of the implant material was noted. Residual implant material was still present on gross and histologic examination in rabbits at 9, 12, 15, and 18 months. Residue of a screw was still palpable in 1 rabbit at 18 months. There was no evidence of cyst formation in any of the examined specimens. Macrophages and giant cells were present in most of the specimens at 9, 12, 15, and 18 months. Findings from the current study revealed a relative short resorption time (9 mo) and normal inflammatory sequelae in an adult rabbit model. These findings suggest that these plates may be used safely in fixing the pediatric craniofacial skeleton. PMID:18520394

  2. Determination of the of rate cross slip of screw dislocations

    PubMed

    Vegge; Rasmussen; Leffers; Pedersen; Jacobsen

    2000-10-30

    The rate for cross slip of screw dislocations during annihilation of screw dipoles in copper is determined by molecular dynamics simulations. The temperature dependence of the rate is seen to obey an Arrhenius behavior in the investigated temperature range: 225-375 K. The activation energy and the effective attempt frequency can therefore be extracted from the simulations. The transition state energy for the annihilation process is calculated by identifying the transition state using the nudged elastic band path technique. The two activation energies agree very well, indicating that transition state theory is applicable for this type of process. PMID:11041947

  3. 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 for each displaced bone segment. According to our preliminary clinical study, a comparison between Fastening Strength, displaced bone volume and mean voxel intensity showed similar results (p < 0.1) between the virtually templated plans and the post-operative outcome following the traditional clinical approach. This study has demonstrated the feasibility of the platform in providing estimates the pedicle screw fastening strength via virtual implantation, given the intrinsic vertebral geometry and bone mineral density, enabling the selection of the optimal implant dimension adn trajectory for improved strength.

  4. Screw- versus cement-retained implant restorations: current concepts.

    PubMed

    Lee, Angie; Okayasu, Kozue; Wang, Hom-Lay

    2010-02-01

    The debate between screw- versus cement-retained implant prostheses has long been discussed but the best type of implant prosthesis remains controversial among practitioners. An understanding of their properties will help the clinician in selecting the ideal prosthesis for each clinical case while promoting final esthetic outcomes. With the evolving technology and knowledge, an update of the current trends is necessary. This article provides an overview of the different characteristics of screw- and cement-retained implant restorations, and how they may influence the esthetics, retrievability, retention, passivity, occlusion, accessibility, cost, and provisional restorations. Problems and complications frequently encountered are discussed and treatment solutions are proposed. PMID:20147811

  5. Effect of cement washout on loosening of abutment screws and vice versa in screw- and cement- retained implant-supported dental prosthesis

    PubMed Central

    Kim, Seok-Gyu; Son, Mee-Kyoung

    2015-01-01

    PURPOSE The purpose of this study was to examine the abutment screw stability of screw- and cement-retained implant-supported dental prosthesis (SCP) after simulated cement washout as well as the stability of SCP cements after complete loosening of abutment screws. MATERIALS AND METHODS Thirty-six titanium CAD/CAM-made implant prostheses were fabricated on two implants placed in the resin models. Each prosthesis is a two-unit SCP: one screw-retained and the other cemented. After evaluating the passive fit of each prosthesis, all implant prostheses were randomly divided into 3 groups: screwed and cemented SCP (Control), screwed and noncemented SCP (Group 1), unscrewed and cemented SCP (Group 2). Each prosthesis in Control and Group 1 was screwed and/or cemented, and the preloading reverse torque value (RTV) was evaluated. SCP in Group 2 was screwed and cemented, and then unscrewed (RTV=0) after the cement was set. After cyclic loading was applied, the postloading RTV was measured. RTV loss and decementation ratios were calculated for statistical analysis. RESULTS There was no significant difference in RTV loss ratio between Control and Group 1 (P=.16). No decemented prosthesis was found among Control and Group 2. CONCLUSION Within the limits of this in vitro study, the stabilities of SCP abutment screws and cement were not significantly changed after simulated cement washout or screw loosening. PMID:26140172

  6. 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 fixation was related to pain (F?=?3.19, p?=?0.046) and a tendency to worse outcome (F?=?2.43, p?=?0.071). No relationship was found between nonunion and working length. Conclusion Despite modern fixation techniques, distal femoral fractures often result in persistent disability and worse clinical outcomes. Soft tissue management seems to be important. Submuscular plate insertion reduced the nonunion rate. Preexisting total knee arthroplasty increased the risk of hardware failure. Further studies determining factors that improve outcome are warranted. PMID:24279475

  7. A novel approach toward pedicle screw placement in the thoracic spine

    Microsoft Academic Search

    John Thalgott; Mark Kabins; James Giuffre

    2002-01-01

    Purpose of study: Because of the smaller size of the thoracic pedicle, primarily in the coronal plane, most surgeons have opted to avoid the used of transpedicular screws in the thoracic spine. A new technique for placement of screws through thoracic pedicles with and without lateral wall violation is described.Methods used: From April 1992 through February 1999, 1,064 pedicle screws

  8. Bone cement or bone substitute augmentation of pedicle screws improves pullout strength in posterior spinal fixation

    Microsoft Academic Search

    S. L. Evans; C. M. Hunt; S. Ahuja

    2002-01-01

    Pedicle screws are widely used to fix posterior spinal implants. However, in some situations, such as at the ends of long constructs in scoliosis correction, the screws may pull out of the pedicles. This limits the use of pedicle screw fixation where bone quality is poor. The aim of this study was to investigate the effect of using either a

  9. Influence of the coating material on the loosing of dental implant abutment screw joints

    Microsoft Academic Search

    C. N. Elias; D. C. Figueira; P. R. Rios

    2006-01-01

    Dental implant abutment screw joints tend to loosen and prosthesis rotation has been observed under clinical conditions. Some dental implant manufacturers suggest coated abutment screw to prevent the displacement of dental prosthesis. In the present work, the opening torque (N cm) was measured as a function of tightening torque (N cm) for dental implant abutment screws coated with four different

  10. MECHANICS OF THE TAPER INTEGRATED SCREWED-IN (TIS) ABUTMENTS USED IN DENTAL IMPLANTS

    E-print Network

    Müftü, Sinan

    1 MECHANICS OF THE TAPER INTEGRATED SCREWED-IN (TIS) ABUTMENTS USED IN DENTAL IMPLANTS by Dinçer. Keywords: Dental implants; Taper lock; Morse taper; Conical interference fit; Tapered screw; Screw mechanics; Loosening torque, Tightening torque #12;3 INTRODUCTION A dental implant system serves

  11. On Screw-Transform Manifolds Russell A. Manning Charles R. Dyer

    E-print Network

    Dyer, Charles R.

    describes the mathematical theory of screw-transform manifolds and their use in camera self cali- brationOn Screw-Transform Manifolds Russell A. Manning Charles R. Dyer Department of Computer Sciences transformation that moves the camera from the first location to the second location is equivalent to a screw

  12. Improved Screw Theory using Second Order Terms Jun Takamatsu Hiroshi Kimurat Katsushi Ikeuchi

    E-print Network

    Ikeuchi, Katsushi

    Improved Screw Theory using Second Order Terms Jun Takamatsu Hiroshi Kimurat Katsushi Ikeuchi this displacement, the screw theory is employed. It is equivalent to the first order Taylor expansion of the displacement. The screw theory is very convenient, because the displacement is formulated as simulta- neous

  13. Calculating Possible Local Displacement of Curve Objects using Improved Screw Theory

    E-print Network

    Ikeuchi, Katsushi

    Calculating Possible Local Displacement of Curve Objects using Improved Screw Theory Jun Takamatsu of objects have been pro- posed. To calculate this displacement, the screw theory is employed polyhedral objects only. Because the screw theory cannot treat curvature information of objects

  14. The singularity study of spatial hybrid mechanisms based on screw theory

    Microsoft Academic Search

    J.-S. Zhao; K. Zhou; Z.-J. Feng; Z.-Y. Tan

    2005-01-01

    In this paper, a novel methodology based on screw theory to study the singularity of spatial hybrid mechanisms is presented. According to the physical meaning of inverse screws, we introduce the equivalent kinematic screws to replace the function of those of the parallel limbs, and therefore the hybrid branch can be transformed into a pure series kinematic chain which can

  15. Gauge-field-theory solution of the elastic state of a screw dislocation in a dispersive

    E-print Network

    Sharma, Pradeep

    Gauge-field-theory solution of the elastic state of a screw dislocation in a dispersive (non the solution of most screw dislocation problems in the gauge non-local theory of defects, provided, NY 12309, USA The relaxed state of a type of topological defect (screw dislocation) located

  16. Collision Prediction for Polyhedra under Screw Motions Byungmoon Kim Jarek Rossignac

    E-print Network

    Rossignac, Jarek

    General Terms Theory Keywords Collision Detection, Screw Motion, Polyhedra Permission to make digitalCollision Prediction for Polyhedra under Screw Motions Byungmoon Kim Jarek Rossignac bmkim the relative motion between pairs of objects by a sequence of screw motion segments, each defined

  17. Screw-theoretic analysis models for felid jaw mechanisms Michael J. Delsignore, Venkat N. Krovi *

    E-print Network

    Krovi, Venkat

    Elsevier Ltd. All rights reserved. Keywords: Screw-theory; Musculoskeletal systems; Optimization; CableScrew-theoretic analysis models for felid jaw mechanisms Michael J. Delsignore, Venkat N. Krovi of quasi-static computational models for musculoskeletal analysis, leverag- ing screw-theoretic techniques

  18. Hamstring tendon fixation using interference screws: a biomechanical study in calf tibial bone

    Microsoft Academic Search

    A Weiler; RF Hoffmann; AC Stähelin; HJ Bail; CJ Siepe; NP Südkamp

    1998-01-01

    It has recently been shown that graft fixation close to the ACL insertion site is optimal in order to increase anterior knee stability. Hamstring tendon fixation using interference screws offers this possibility and a round threaded titanium interference screw has been previously developed. The use of a round threaded biodegradable interference screw may be equivalent. In addition, to increase initial

  19. Hyperammonaemia with distal renal tubular acidosis

    PubMed Central

    Miller, S; Schwartz, G

    1997-01-01

    ?? The case is reported of an infant with hyperammonaemia secondary to severe distal renal tubular acidosis. A clinical association between increased concentrations of ammonia in serum and renal tubular acidosis has not previously been described. In response to acidosis the infant's kidneys presumably increased ammonia synthesis but did not excrete ammonia, resulting in hyperammonaemia. The patient showed poor feeding, frequent vomiting, and failure to thrive, but did not have an inborn error of metabolism. This case report should alert doctors to consider renal tubular acidosis in the differential diagnosis of severely ill infants with metabolic acidosis and hyperammonaemia.?? PMID:9487970

  20. Distal radius-ulna fractures in children.

    PubMed

    Pannu, Gurpal S; Herman, Marty

    2015-04-01

    Fractures involving the distal radius and ulna are commonly seen in children and adolescents. Management of these injuries in pediatric patients should include assessment of the neurovascular status of the extremity, associated soft-tissue injury, and, most importantly, possible involvement of the physes of the radius and ulna. Treatment of these injuries may vary from simple casting and radiographic follow-up to urgent reduction and surgical fixation. Regardless of the initial treatment plan, the treating surgeon must remain aware of the potential for both early and late complications that may affect outcomes. PMID:25771318

  1. VSHOT Measurements of Distal II Dish Concentrators

    SciTech Connect

    Jones, S.A.

    1998-12-14

    The Video Scanning Hartmann Optical Tester (VSHOT) is a laser ray-trace tool for measuring the slope error of solar concentrator mirrors. The VSHOT measurements made on two, 8.5-m diameter, Distal II dishes represent its first use on a concentrator installed and operating in the field. A number of valuable lessons were learned regarding the use of the VSHOT for outdoor testing. The two dishes were found to have overall figure-of-merit RMS slope errors from an ideal parabola of 2.99 and 3.18 milliradians. The VSHOT measurements compare well qualitatively with distant observer photographs made using a colored concentric ring target.

  2. [Reconstruction of digestive tract after distal gastrectomy].

    PubMed

    Hu, Xiang

    2014-05-01

    There are various types of digestive tract reconstruction techniques after distal gastrectomy. Among them, Billroth I and II are still the predominant option in China at present. In recent years, Roux-en-Y configuration, jejunal interposition, J-pouch interposition (JPI), double-tract reconstruction, pylorus-preserving method, and laparoscopic reconstruction and anastomosis techniques have gained more attention in recent years. Although there is no universal and explicit guideline, the current consensus is that the reconstruction style should be adopted by the principles of digestive tract reconstruction, based on patient's condition, socioeconomic status and surgeon's experience. PMID:24859945

  3. Creation of distal canine limb lymphedema

    SciTech Connect

    Chen, H.C.; Pribaz, J.J.; O'Brien, B.M.; Knight, K.R.; Morrison, W.A.

    1989-06-01

    A canine model of distal limb lymphedema was established in order to study the treatment of this condition by lymph node transfer. This model was more difficult to establish than whole-limb lymphedema. Significant edema was achieved by a combination of preoperative irradiation and circumferential removal of skin from the irradiated areas followed by removal of the contents of the popliteal fossa. Despite these measures, it was not possible to produce lymphedema in every case, possibly because of the presence of lymphaticovenous shunts and panvascular compensation mechanisms.

  4. Calculation of axial forces on the screw in rubber extruders

    Microsoft Academic Search

    S. P. Konclrakov; M. S. Samoilov; N. V. Tyabin; A. G. Govsha

    1972-01-01

    A special hydraulic thrust bearing (Fig. 1) was developed for measuring the axial forces of the screw. The thrust bearing consists of a body 7, a guiding collar 4, a rubber collar 6, assembled in one unit using a clamping nut 5. The cavity formed between the body 7 and the collar 6, and also the connecting pipe 9 and

  5. 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

  6. Sacroiliac screw fixation: A mini review of surgical technique

    PubMed Central

    Alvis-Miranda, Hernando Raphael; Farid-Escorcia, Hector; Alcalá-Cerra, Gabriel; Castellar-Leones, Sandra Milena; Moscote-Salazar, Luis Rafael

    2014-01-01

    The sacral percutaneous fixation has many advantages but can be associated with a significant exposure to X-ray radiation. Currently, sacroiliac screw fixation represents the only minimally invasive technique to stabilize the posterior pelvic ring. It is a technique that should be used by experienced surgeons. We present a practical review of important aspects of this technique. PMID:25336831

  7. Twin-screw extrusion of ‘Pesta’-encapsulated biocontrol agents

    Microsoft Academic Search

    D. J. Daigle; W. J. Connick; C. D. Boyette; M. P. Lovisa; K. S. Williams; M. Watson

    1997-01-01

    ‘Pesta’ granules in which fungal propagules are encapsulated in a wheat gluten matrix were prepared in multipound quantities by twin-screw extrusion and fluid bed drying. Dough formulations for extrusion contained wheat flour and kaolin, or wheat flour, kaolin and rice flour, plus water and fungal inoculum. Conidial inoculum of Colletotrichum truncatum, a pathogen of the weed hemp sesbania (Sesbania exaltata),

  8. 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.

  9. Successive Screw Approximation in Ising Lattice Gauge Theory

    NASA Astrophysics Data System (ADS)

    Katsumori, H.

    1984-01-01

    Kramers and Wannier's successive screw technique is applied to the three-dimensional Ising lattice gauge theory. The largest eigenvalue of the transfer matrix is directly calculated on a computer, independently of Monte Carlo simulation. Anomalous behavior of the specific heat implies the existence of a phase transition.

  10. Force between two parallel screw dislocations - gauge theory result

    NASA Astrophysics Data System (ADS)

    Valsakumar, M. C.; Sahoo, Debendranath

    1996-02-01

    The expression for the force between two parallel screw dislocations is derived in the framework of the Yang-Mills-type gauge theory of dislocations earlier proposed by Kadic and Edelen [A gauge theory of dislocations and disclinations (Springer, Berlin, 1983)] and later developed by Valsakumar and Sahoo [Bull. Mater. Sci. 10 (1988) 3].

  11. Dynamics of parallel manipulators by means of screw theory

    Microsoft Academic Search

    J. Gallardo; J. M. Rico; A. Frisoli; D. Checcacci; M. Bergamasco

    2003-01-01

    An approach to the dynamic analysis of parallel manipulators is presented. The proposed method, based on the theory of screws and on the principle of virtual work, allows a straightforward calculation of the actuator forces as a function of the external applied forces and the imposed trajectory. In order to show the generality of such a methodology, two case studies

  12. Jerk Influence Coefficients, via Screw Theory, of Closed Chains

    Microsoft Academic Search

    J. Gallardo-Alvarado; J. M. Rico-Martinez

    2001-01-01

    In this paper a novel method for determining the kinematic influence coefficients up to the jerk analysis of closed chains with multiple degrees of freedom by means of screw theory, also known as motor algebra, is introduced. A closed chain is obtained by rigidly attaching the end-effector of a serial chain to the base link. This condition ensures that the

  13. Force between two parallel screw dislocations — gauge theory result

    Microsoft Academic Search

    M. C. Valsakumar; Debendranath Sahoo

    1996-01-01

    The expression for the force between two parallel screw dislocations is derived in the framework of the Yang-Mills-type gauge theory of dislocations earlier proposed by Kadic and Edelen [A gauge theory of dislocations and disclinations (Springer, Berlin, 1983)] and later developed by Valsakumar and Sahoo [Bull. Mater. Sci. 10 (1988) 3].

  14. A computational analysis of screw transformations in robotics

    Microsoft Academic Search

    JANEZ FUNDA; RICHARD P. PAUL

    1990-01-01

    A computational analysis and a comparison of line-oriented representations of general (i.e. rotational and translational) spatial displacements of rigid bodies are presented. Four mathematical formalisms for effecting a general spatial screw displacement are discussed and analyzed in terms of computational efficiency in performing common operations needed in kinematic analysis of multilinked spatial mechanisms. The corresponding algorithms are analyzed in terms

  15. 39. VIEW OF VESSEL STERNON IN DRYDOCK. NOTE TWIN SCREWS ...

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

    39. VIEW OF VESSEL STERN-ON IN DRYDOCK. NOTE TWIN SCREWS AND RUDDER. GENTLEMEN IN VIEW UNKNOWN Original 5'x5' photograph taken by Robert S. Douglas in 1966 - Pilot Schooner "Alabama", Moored in harbor at Vineyard Haven, Vineyard Haven, Dukes County, MA

  16. The empirical modeling of a Lysholm screw expander

    Microsoft Academic Search

    R. F. Stiedel; K. A. Brown; D. H. Pankow

    1983-01-01

    This is a description of the development of an engine model for the prediction of mass flow rate, power, efficiency and exhaust quality for a Lysholm Screw Expander at a given set of operating conditions. The testing of an expander having a rotor diameter of 130 mm (5.12 inches) and an expansion ratio of 5.3 was performed with simulated geothermal

  17. Screw Type Steam Compressors for Mechanical Vapor Recompression (MVR) Systems 

    E-print Network

    Kawamura, K.; Apaloo, Thomas-L.

    1986-01-01

    the low pressure steam to a usable pressure for reinjection into the process stream. Mycom has developed, designed and installed two large MVR systems using screw compressors: one for a brewery and the other for a whiskey plant. This paper discusses...

  18. Outpatient percutaneous screw fixation of the acute Jones fracture

    Microsoft Academic Search

    Norman Mindrebo; K. Donald Shelbourne; Charles D. Van Meter; Arthur C. Rettig

    1993-01-01

    Nine patients (8 men and 1 woman, ranging in age from 17 to 22 years) who sustained a Jones fracture were treated with percutaneous intramedullary screw fixation as outpatients. All of the patients were varsity athletes. Seven were Division I scholarship athletes. Beginning at 7 to 10 days after surgery, all patients were allowed weightbearing as tolerated with a CAM

  19. Review Article: Screw Compressors in Refrigeration and Air Conditioning

    Microsoft Academic Search

    Nikola Stoši?

    2004-01-01

    Recent advances in the techniques for manufacturing vital parts, such as rotors and bearings, have enabled improvements to be made to screw compressors that were difficult to imagine only a few years ago. This has inevitably influenced the prospects for these machines in refrigeration and air-conditioning applications. Some aspects of this are presented, together with well known but not always

  20. A Screw Syzygy with Applications to Robot Singularity Computation

    Microsoft Academic Search

    J. M. Selig; Peter Donelan

    A syzygy is a relation between invariants. In this paper a syzygy is presented between invariants of sequences of six screws\\u000a under the action of the Euclidean group. This relation is useful in simplifying the computation of the determinant of a robot\\u000a Jacobian and hence can be used to investigate the singularities of robot manipulators.

  1. Covering the screw-access holes of implant restorations in the esthetic zone: a clinical report.

    PubMed

    Saboury, Abolfazl; Gooya, Ali

    2014-11-01

    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

  2. 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)

  3. Bioabsorbable Versus Metallic Screw Fixation for Tibiofibular Syndesmotic Ruptures: A Meta-Analysis.

    PubMed

    van der Eng, Dorien M; Schep, Niels W L; Schepers, Tim

    2015-01-01

    Ankle fractures with syndesmotic rupture require operative treatment. In most cases, this consists of fixation of the tibiofibular joint with 1 or more screws. Bioabsorbable screws are used for the same purpose but have the advantage that screw removal is unnecessary. The aim of the present study was to compare the results of bioabsorbable and metallic syndesmotic screws. A systematic search was performed in the Ovid MEDLINE electronic database and Google Scholar. Three randomized controlled trials and one comparison study, with 260 patients, were included. The experimental group consisted of patients with syndesmotic injuries treated with bioabsorbable screws versus the control group (patients treated with metallic screws). The primary outcomes were complications and wound infections. No statistically significant difference was demonstrable in the overall number of complications between the 2 groups. In the group of patients with a bioabsorbable screw, 32 of 137 (23.4%) experienced a complication versus 7 of 123 patients (5.7%) with a metallic screw. Data on wound-related complications showed no statistically significant difference, 19.7% versus 5.7%. The average maximum range of motion in both groups was comparable. Bioabsorbable syndesmotic screws and metallic syndesmotic screws were comparable with respect to the incidence of complications and range of motion. However, the absolute number of complications was greater with bioabsorbable screws. PMID:25960058

  4. Easy retrieval of polyaxial tulip-head pedicle screws by “U” rod technique

    PubMed Central

    Isik, Cengiz; Altinel, Levent; Ates, Ali; Ozdemir, Mustafa

    2009-01-01

    The number of fusion surgeries increase each year which also increase the need for implant removal. In some cases, it can be extremely hard to remove a pedicle screw especially when there is a mismatch of the screw and the screwdriver. Also the screwdrivers can be contaminated during the operation, and this will cause a delay till the instruments are re-sterilized. There is a need for the removal of screws without special instruments. We describe a method for removing tulip-head polyaxial pedicle screws without special instruments. The screws are removed using an Allen key, a rod bender and a “U” shaped rod. We successfully removed 76 screws in 11 recent cases without any complications. The “U” rod technique is a simple and useful technique for the removal of tulip-head polyaxial screws. PMID:19618219

  5. Unraveling the genetics of distal hereditary motor neuronopathies

    Microsoft Academic Search

    Joy Irobi; Ines Dierick; Albena Jordanova; Kristl G. Clayes; Peter De Jonghe; Vincent Timmerman

    2006-01-01

    The hereditary motor neuronopathies (HMN [MIM 158590]) are heterogeneous group of disorders characterized by an exclusive\\u000a involvement of the motor part of the peripheral nervous system. They are usually subdivided in proximal HMN, i.e., the classical\\u000a spinal muscular atrophy syndromes and distal hereditary motor neuronopathies (distal HMN) that clinically resemble Charcot-Marie-Tooth\\u000a syndromes. In this review, we concentrate on distal HMN.

  6. Interlocked optimization and fast gradient algorithm for a seismic inverse problem

    SciTech Connect

    Metivier, Ludovic, E-mail: ludovic.metivier@gmail.com [LAGA, Universite Paris XIII, 99 Avenue Jean-Baptiste Clement, 93000 Epinay-Villetaneuse (France)

    2011-08-10

    Highlights: {yields} A 2D extension of the 1D nonlinear inversion of well-seismic data is given. {yields} Appropriate regularization yields a well-determined large scale inverse problem. {yields} An interlocked optimization loop acts as an efficient preconditioner. {yields} The adjoint state method is used to compute the misfit function gradient. {yields} Domain decomposition method yields an efficient parallel implementation. - Abstract: We give a nonlinear inverse method for seismic data recorded in a well from sources at several offsets from the borehole in a 2D acoustic framework. Given the velocity field, approximate values of the impedance are recovered. This is a 2D extension of the 1D inversion of vertical seismic profiles . The inverse problem generates a large scale undetermined ill-conditioned problem. Appropriate regularization terms render the problem well-determined. An interlocked optimization algorithm yields an efficient preconditioning. A gradient algorithm based on the adjoint state method and domain decomposition gives a fast parallel numerical method. For a realistic test case, convergence is attained in an acceptable time with 128 processors.

  7. Distal Xq duplication and functional Xq disomy

    PubMed Central

    Sanlaville, Damien; Schluth-Bolard, Caroline; Turleau, Catherine

    2009-01-01

    Distal Xq duplications refer to chromosomal disorders resulting from involvement of the long arm of the X chromosome (Xq). Clinical manifestations widely vary depending on the gender of the patient and on the gene content of the duplicated segment. Prevalence of Xq duplications remains unknown. About 40 cases of Xq28 functional disomy due to cytogenetically visible rearrangements, and about 50 cases of cryptic duplications encompassing the MECP2 gene have been reported. The most frequently reported distal duplications involve the Xq28 segment and yield a recognisable phenotype including distinctive facial features (premature closure of the fontanels or ridged metopic suture, broad face with full cheeks, epicanthal folds, large ears, small and open mouth, ear anomalies, pointed nose, abnormal palate and facial hypotonia), major axial hypotonia, severe developmental delay, severe feeding difficulties, abnormal genitalia and proneness to infections. Xq duplications may be caused either by an intrachromosomal duplication or an unbalanced X/Y or X/autosome translocation. In XY males, structural X disomy always results in functional disomy. In females, failure of X chromosome dosage compensation could result from a variety of mechanisms, including an unfavourable pattern of inactivation, a breakpoint separating an X segment from the X-inactivation centre in cis, or a small ring chromosome. The MECP2 gene in Xq28 is the most important dosage-sensitive gene responsible for the abnormal phenotype in duplications of distal Xq. Diagnosis is based on clinical features and is confirmed by CGH array techniques. Differential diagnoses include Prader-Willi syndrome and Alpha thalassaemia-mental retardation, X linked (ATR-X). The recurrence risk is significant if a structural rearrangement is present in one of the parent, the most frequent situation being that of an intrachromosomal duplication inherited from the mother. Prenatal diagnosis is performed by cytogenetic testing including FISH and/or DNA quantification methods. Management is multi-specialist and only symptomatic, with special attention to prevention of malnutrition and recurrent infections. Educational and rehabilitation support should be offered to all patients. Disease name Xq duplications, Xq functional disomy PMID:19232094

  8. Laparoscopic Nephroureterectomy: The Distal Ureteral Dilemma

    PubMed Central

    Srirangam, Shalom J.; van Cleynenbreugel, Ben; van Poppel, Hein

    2009-01-01

    Transitional cell carcinoma affecting the upper urinary tract, though uncommon, constitutes a serious urologic disease. Radical nephroureterectomy remains the treatment of choice but has undergone numerous modifications over the years. Although the standard technique has not been defined, the laparoscopic approach has gained in popularity in the last two decades. The most appropriate oncological management of the distal ureteral and bladder cuff has been a subject of much debate. The aim of the nephroureterectomy procedure is to remove the entire ipsilateral upper tract in continuity while avoiding extravesical transfer of tumor-containing urine during bladder surgery. A myriad of technical modifications have been described. In this article, we review the literature and present an overview of the options for dealing with the lower ureter during radical nephroureterectomy. PMID:19020654

  9. Comparison between Bilateral C2 Pedicle Screwing and Unilateral C2 Pedicle Screwing, Combined with Contralateral C2 Laminar Screwing, for Atlantoaxial Posterior Fixation

    PubMed Central

    Hongo, Michio; Kobayashi, Takashi; Suzuki, Tetsuya; Abe, Eiji; Shimada, Yoichi

    2014-01-01

    Study Design A retrospective study. Purpose To compare clinical and radiological outcomes between bilateral C2 pedicle screwing (C2PS) and unilateral C2PS, combined with contralateral C2 laminar screwing (LS), for posterior atlantoaxial fixation. Overview of Literature Posterior fixation with C1 lateral mass screwing (C1LMS) and C2PS (C1LMS-C2PS method) is an accepted procedure for rigid atlantoaxial stabilization. However, conventional bilateral C2PS is not always allowed in this method due to anatomical variations of C2 pedicles and/or asymmetry of the vertebral artery. Although unilateral C2PS plus contralateral LS (C2PS+LS) is an alternative in such cases, the efficacy of this procedure has not been evaluated in controlled studies (i.e., with bilateral C2PS as a control). Methods Clinical and radiological records of patients who underwent the C1LMS-C2PS method, using unilateral C2PS+LS (n=9), and those treated using conventional bilateral C2PS (n=10) were compared, with a minimum two years follow-up. Results Postoperative complications related to the unilateral C2PS+LS technique included one case of spontaneous spinous process fracture of C2. A C1 anterior arch fracture occurred after a fall in one patient, who underwent bilateral C2PS and C1 laminectomy. No significant differences were seen between the groups in reduction of neck pain after surgery or improvement of neurological status, as evaluated using the Japanese Orthopaedic Association score. A delayed union occurred in one patient each of the groups, with the final fusion rate being 100% in both groups. Conclusions Clinical and radiological outcomes of unilateral C2PS+LS were comparable with those of the bilateral C2PS fixation technique for the C1LMS-C2PS method. PMID:25558320

  10. Use of C2 spinous process screw for posterior cervical fixation as substitute for laminar screw in a patient with thin laminae

    PubMed Central

    Nagata, Kosei; Baba, Satoshi; Chikuda, Hirotaka; Takeshita, Katsushi

    2013-01-01

    Rigid screw fixation of C2 including transarticular screw and pedicle screw contain the risk of vertebral artery (VA) injury. On the other hand, translaminar screws are considered to be safer for patients with anomalous VA. But C2 translaminar screw placement was limited in patients who have thin laminas and there is marked variation in C2 laminar thickness. Appropriate C2 fixation method for a patient who has thin laminas and high-riding VA together was controversial. Here, we present a case of an elderly Asian woman who had thin laminas and high-riding VA together with progressive myelopathy to report a first case of C2 spinous process screw insertion. Although the stability and safety of C2 spinous process screw was reported in cadaver series, there was no clinical report to our knowledge. Spinous process screw can be an option of C2 fixation for patients with high-riding VA and severe degenerated cervical spines including thin C2 laminas. PMID:23814004

  11. The role of the kneading paddle and the effects of screw revolution speed and water content on the preparation of solid dispersions using a twin-screw extruder.

    PubMed

    Nakamichi, Kouichi; Nakano, Tomio; Yasuura, Hiroyuki; Izumi, Shogo; Kawashima, Yoshiaki

    2002-07-25

    The twin-screw hot-melt extrusion process is useful for preparing solid dispersions which can improve the dissolution and absorption of drugs. The kneading paddle elements of the screws play an important role in changing the crystallinity and dissolution properties of a solid dispersion of kneaded nifedipine-hydroxypropylmethylcellulose phthalate (NP-HPMCP). After operating the machine, a small amount of kneaded material adhering to the screws was collected and its physicochemical properties examined. Samples from the kneading paddle with a twist angle of 60 degrees were transparent and exhibited super-saturation on dissolution testing. When the kneading paddle elements were detached from the screws and only the feed screw elements were operated, the physicochemical properties of the extruded material were significantly influenced by the operating conditions of the machine e.g. revolution rate of screws, and the amount of water added to the feed materials. Slow revolution of the screws and the addition of a suitable amount of water to the mixture increased the rate of drug dissolution, although no super-saturation occurred. As the kneading paddle elements can retain the mixture in the machine for a longer period under intense shear, desired solid dispersions can be prepared routinely irrespective of the operating conditions. Moreover, a capillary rheometer can be useful to predetermine the amount of water added and the temperature for the preparation of solid dispersions using a twin-screw extruder. PMID:12100848

  12. Prevention of arthrofibrosis after arthroscopic screw fixation of tibial spine fracture in children and adolescents.

    PubMed

    Parikh, Shital N; Myer, David; Eismann, Emily A

    2014-01-01

    Arthrofibrosis is a major complication of tibial spine fracture treatment in children, potentially resulting in knee pain, quadriceps weakness, altered gait, decreased function, inability to return to sports, and long-term osteoarthritis. Thus, prevention rather than treatment of arthrofibrosis is desirable. The purpose of this study was to evaluate an aggressive postoperative rehabilitation and early intervention approach to prevent permanent arthrofibrosis after tibial spine fracture treatment and to compare epiphyseal and transphyseal screws for fixation. A consecutive series of 24 patients younger than age 18 with displaced type II and III tibial spine fractures who underwent arthroscopic reduction and screw fixation between 2006 and 2011 were retrospectively reviewed. Final range of motion was compared between patients with epiphyseal (n=12) and transphyseal (n=9) screws. One-third (4 of 12) of patients with epiphyseal screws underwent arthroscopic debridement and screw removal approximately 3 months postoperatively; 3 patients lacked 5° to 15° of extension, 1 experienced pain with extension, and 1 had radiographic evidence of screw pullout, loss of reduction, and resultant malunion. In the transphyseal screw group, 3 patients had 10° loss of extension, and all corrected after arthroscopic debridement and screw removal. The two groups did not significantly differ in time to hardware removal or return to sports or final range of motion. No growth disturbances were identified in patients after transphyseal screw removal. An aggressive approach of postoperative rehabilitation and early intervention after arthroscopic reduction and screw fixation of tibial spine fractures in children was successful in preventing permanent arthrofibrosis. PMID:24683658

  13. Defining Residual Radial Translation of Distal Radius Fractures: A Potential Cause of Distal Radioulnar Joint Instability

    PubMed Central

    Ross, Mark; Di Mascio, Livio; Peters, Susan; Cockfield, Allen; Taylor, Fraser; Couzens, Greg

    2014-01-01

    Background?The aim of this paper is twofold: to raise awareness of the potential problems of leaving residual radial translation of the distal fragment in distal radius fracture fixation and to provide a reproducible, accurate and simple radiographic parameter to define this reduction. The primary goal of all of this is to raise awareness of the malreduction to decrease problems with distal radial ulnar joint instability and to decrease the incidence of what the Authors consider to be unnecessary surgery on the ulnar side of the wrist when the surgeon is confronted with distal radio ulnar joint instability after fixation of a distal radial fracture. The idea is to make the surgeon look at reduction of the radius instead of fixing the ulnar side. We know that in the overwhelming majority of cases in our clinical experience, intraoperative correction of this deformity has avoided the need for ulnar styloid or TFC repair, which we otherwise would have performed had we not been aware of this malreduction. We have deliberately used the word potential in the title to reflect that we are proposing a hypothesis, and that only 40–50 percent of patients have a discrete distal band of the IOM. We have extensive experience over a 15-year period with internal fixation of distal radius fractures and have clearly observed this phenomenon. It is our belief, therefore, that we should be able to present this hypothesis in tandem with the radiographic parameter that we are advocating, to raise awareness of this malreduction of the radius. The radiographic parameter has little relevance unless put into this context. We would consider that the impact and value of this paper would be substantially weakened by removing this component of the title. Patients and Methods?In this study, 100 normal wrist radiographs were reviewed by three fellowship-trained orthopedic surgeons to develop a simple and reproducible technique to measure radial translation. Results?Utilizing the method described, the point of intersection between the ulnar cortex of the shaft of the radius and the lunate left a mean average of 45.48% (range 25–73.68%) of the lunate remaining on the radial side. In the majority of cases more of the lunate resided ulnar to this line. High levels of agreement with inter-rater (intraclass coefficients?=?0.967) and intra-rater (intraclass coefficients?=?0.79) reliability was observed. Conclusions?The results of this study can be used to define a normal standard against which residual radial translation can be measured to assess the reduction of distal radius fractures. This new parameter aids in the development of surgical techniques to correct residual radial translation deformity. In addition, awareness and correction of this potential malreduction at the time of surgery may decrease the need for other procedures on the ulnar side of the wrist to improve DRUJ stability, such as ulnar styloid fixation, TFCC repair, or ligamentous grafting. Level of Evidence?Level II (Diagnostic) PMID:24533242

  14. Structure of screw dislocation core in Ta at high pressure

    SciTech Connect

    Wang, Shaofeng, E-mail: sfwang@cqu.edu.cn; Jiang, Na; Wang, Rui; Zhou, Ying [Institute for Structure and Function and Department of Physics, Chongqing University, Chongqing 400030 (China)

    2014-03-07

    The core structure and Peierls stress of the 1/2 ?111?(110) screw dislocation in Ta have been investigated theoretically using the modified Peierls–Nabarro theory that takes into account the discreteness effect of crystal. The lattice constants, the elastic properties, and the generalized-stacking-fault energy(?-surface) under the different pressures have been calculated from the electron density functional theory. The core structure of dislocation is determined by the modified Peierls equation, and the Peierls stress is evaluated from the dislocation energy that varies periodically as dislocation moves. The results show the core width and Peierls stress in Ta are weakly dependent of the pressure up to 100?GPa when the length and stress are measured separately by the Burgers vector b and shear modulus ?. This indicates that core structure is approximately scaling invariant for the screw dislocation in Ta. The scaled plasticity of Ta changes little in high pressure environment.

  15. Analysis of Eyring-Powell Fluid in Helical Screw Rheometer

    PubMed Central

    Siddiqui, A. M.; Haroon, T.; Zeb, M.

    2014-01-01

    This paper aims to study the flow of an incompressible, isothermal Eyring-Powell fluid in a helical screw rheometer. The complicated geometry of the helical screw rheometer is simplified by “unwrapping or flattening” the channel, lands, and the outside rotating barrel, assuming the width of the channel is larger as compared to the depth. The developed second order nonlinear differential equations are solved by using Adomian decomposition method. Analytical expressions are obtained for the velocity profiles, shear stresses, shear at wall, force exerted on fluid, volume flow rates, and average velocity. The effect of non-Newtonian parameters, pressure gradients, and flight angle on the velocity profiles is noticed with the help of graphical representation. The observation confirmed the vital role of involved parameters during the extrusion process. PMID:24707194

  16. Structure of screw dislocation core in Ta at high pressure

    NASA Astrophysics Data System (ADS)

    Wang, Shaofeng; Jiang, Na; Wang, Rui; Zhou, Ying

    2014-03-01

    The core structure and Peierls stress of the 1/2?111?{110} screw dislocation in Ta have been investigated theoretically using the modified Peierls-Nabarro theory that takes into account the discreteness effect of crystal. The lattice constants, the elastic properties, and the generalized-stacking-fault energy(?-surface) under the different pressures have been calculated from the electron density functional theory. The core structure of dislocation is determined by the modified Peierls equation, and the Peierls stress is evaluated from the dislocation energy that varies periodically as dislocation moves. The results show the core width and Peierls stress in Ta are weakly dependent of the pressure up to 100 GPa when the length and stress are measured separately by the Burgers vector b and shear modulus ?. This indicates that core structure is approximately scaling invariant for the screw dislocation in Ta. The scaled plasticity of Ta changes little in high pressure environment.

  17. Treatment and complications in flaccid neuromuscular scoliosis (Duchenne muscular dystrophy and spinal muscular atrophy) with posterior-only pedicle screw instrumentation

    PubMed Central

    Modi, Hitesh N.; Hong, Jae-Young; Cho, Jae-Woo; Park, Jong-Hoon; Yang, Jae-Hyuk

    2009-01-01

    Literature has described treatment of flaccid neuromuscular scoliosis using different instrumentation; however, only one article has been published using posterior-only pedicle screw fixation. Complications using pedicle screws in paralytic neuromuscular scoliosis has not been described before. To present results and complications with posterior-only pedicle screws, a retrospective study was carried out in 27 consecutive patients with flaccid neuromuscular scoliosis (Duchenne muscular dystrophy and spinal muscular atrophy), who were operated between 2002 and 2006 using posterior-only pedicle screw instrumentation. Immediate postoperative and final follow-up results were compared using t test for Cobb angle, pelvic obliquity, thoracic kyphosis and lumbar lordosis. Perioperative and postoperative complications were noted from the hospital records of each patient. Complications, not described in literature, were discussed in detail. Average follow-up was 32.2 months. Preoperative, immediate postoperative and final follow-up Cobb angle were 79.8°, 30.2° (63.3% correction, p < 0.0001) and 31.9°, respectively; and pelvic obliquity was 18.3°, 8.9° (52% correction, p < 0.0001) and 8.9°. Postoperative thoracic kyphosis remained unchanged from 27.6° to 19.9° (p = 0.376); while lumbar lordosis improved significantly from +15.6° to ?22.4° lordosis (p = 0.0002). Most patients had major to moderate improvement in postoperative functional and ambulatory status compared to the preoperative status. Thirteen (48.1%) perioperative complications were noted with five major complications (four respiratory in the form of hemothorax or respiratory failure that required ventilator support and one death) and eight minor complications (three UTI, two atelectasis, two neurological and one ileus). Postoperatively, we noted complications, such as coccygodynia with subluxation in 7, back sore on the convex side in 4 and dislodging of rod distally in 1 patient making a total of 12 (44.4%) postoperative complications. Of 12 postoperative complications, 6 (50%) required secondary procedure. We conclude that although flaccid neuromuscular scoliosis can be well corrected with posterior-only pedicle screw, there is a high rate of associated complications. PMID:19885687

  18. Proximal versus Distal Validity Coefficients for Teacher Observational Instruments

    ERIC Educational Resources Information Center

    Marzano, Robert J.

    2014-01-01

    This study examined the use of measures of student learning computed using end-of-year assessments (distal measures) versus measures of student learning associated with a single lesson (proximal measures) as criterion scores for the validity of observations of teachers' pedagogical skills. The validity coefficients computed using distal

  19. Distal Prosodic Context Affects Word Segmentation and Lexical Processing

    ERIC Educational Resources Information Center

    Dilley, Laura C.; McAuley, J. Devin

    2008-01-01

    Three experiments investigated the role of distal (i.e., nonlocal) prosody in word segmentation and lexical processing. In Experiment 1, prosodic characteristics of the initial five syllables of eight-syllable sequences were manipulated; the final portions of these sequences were lexically ambiguous (e.g., "note bookworm", "notebook worm"). Distal

  20. Cutaneous Mycobacterium chelonae Infection Extending Distally in a Hemodialysed Patient

    Microsoft Academic Search

    Athanassios Kolivras; Pierre-André De Berdt; Anne Theunis; Luc Hooghe; Josiane De Maubeuge; Max Dratwa; Micheline Song

    2002-01-01

    We report a case of a cutaneous Mycobacterium chelonae infection on the dorsum of the forearm of a patient undergoing chronic hemodialysis. The infection showed a linear and distal extension. This unusual distal dissemination was apparently secondary to a venous reflux, a circulatory repercussion of the patient’s arteriovenous fistula.

  1. Intraoperative sentinel lymph node mapping guides laparoscopic-assisted distal gastrectomy for distal gastric cancer

    PubMed Central

    Liu, Naiqing; Niu, Zhengchuan; Niu, Wei; Peng, Cheng; Zou, Xueqing; Sun, Shuxiang; Shinichi, Obo; Shahbaz, Muhammad; Sun, Qinli; Jun, Niu

    2015-01-01

    Aims: The aim of this retrospective study is to explore the effects of sentinel lymph node (SLN) mapping guided laparoscopic-assisted distal gastrectomy (LADG) for distal gastric cancer. Methods: Two hundred patients were enrolled in this study. One hundred and one patients undergoing SLN guided LADG were designated as the SLN group. Ninety-nine patients having conventional LADG with D1 or D2 lymph node dissection were designated as the control group. Intraoperative and postoperative indicators such as the number of lymph nodes dissected, intraoperative and postoperative conditions, flow cytometry analysis of T lymphocyte subsets and natural killer (NK) cells, survival rates, recurrence rates and postoperative complications were investigated between these two groups. Results: The number of lymph nodes dissected in the SLN group was significantly lesser than that in the control group. Furthermore, in the SLN group, the patients achieved better immunization status, improved intraoperative and postoperative conditions and decreased postoperative complications. There were no significant differences were found in the positive lymph nodes detected, the distance between proximal and distal cutting edge, postoperative survival or recurrence rates. Conclusions: SLN guided LADG for gastric cancer is a safe and effective method and could achieve an equal clinical effect as traditional laparoscopic D1 or D2 radical operation with less operation trauma and better recovery.

  2. Subaxial subluxation after atlantoaxial transarticular screw fixation in rheumatoid patients

    PubMed Central

    Neo, Masashi; Sakamoto, Takeshi; Fujibayashi, Shunsuke; Yoshitomi, Hiroyuki; Nakamura, Takashi

    2009-01-01

    The most common cervical abnormality associated with rheumatoid arthritis (RA) is atlantoaxial subluxation, and atlantoaxial transarticular screw fixation has proved to be one of the most reliable, stable fixation techniques for treating atlantoaxial subluxation. Following C1–C2 fixation, however, subaxial subluxation reportedly can bring about neurological deterioration and require secondary operative interventions. Rheumatoid patients appear to have a higher risk, but there has been no systematic comparison between rheumatoid and non-rheumatoid patients. Contributing radiological factors to the subluxation have also not been evaluated. The objective of this study was to evaluate subaxial subluxation after atlantoaxial transarticular screw fixation in patients with and without RA and to find contributing factors. Forty-three patients who submitted to atlantoaxial transarticular screw fixation without any concomitant operation were followed up for more than 1 year. Subaxial subluxation and related radiological factors were evaluated by functional X-ray measurements. Statistical analyses showed that aggravations of subluxation of 2.5 mm or greater were more likely to occur in RA patients than in non-RA patients over an average of 4.2 years of follow-up, and postoperative subluxation occurred in the anterior direction in the upper cervical spine. X-ray evaluations revealed that such patients had a significantly smaller postoperative C2–C7 angle, and that the postoperative AA angle correlated negatively with this. Furthermore, anterior subluxation aggravation was significantly correlated with the perioperative atlantoaxial and C2–C7 angle changes, and these two changes were strongly correlated to each other. In conclusion, after atlantoaxial transarticular screw fixation, rheumatoid patients have a greater risk of developing subaxial subluxations. The increase of the atlantoaxial angel at the operation can lead to a decrease in the C2–C7 angle, followed by anterior subluxation of the upper cervical spine and possibly neurological deterioration. PMID:19337758

  3. Kinematics of a Hybrid Manipulator by Means of Screw Theory

    Microsoft Academic Search

    J. GALLARDO-ALVARADO

    2005-01-01

    In this work the kinematics of a hybrid manipulator, namely a fully parallel-serial manipulator, with a particular topology\\u000a is approached by means of the theory of screws. Given the length of the six independent limbs, the forward position analysis\\u000a of the mechanism under study, indeed the computation of the resulting pose, position and orientation, of the end-platform\\u000a with respect to

  4. A magnetoelectric screw dislocation interacting with a circular layered inclusion

    Microsoft Academic Search

    Ming-Ho Shen

    2008-01-01

    Within the framework of the linear theory of magnetoelectroelasticity, the problem of a circular layered inclusion interacting with a generalized screw dislocation under remote anti-plane shear stress and in-plane magnetoelectric loads is investigated in this paper. The generalized dislocation can be located either in the matrix or in the circular layered inclusion. The layers are coaxial cylinders of annular cross-sections

  5. Laparoscopic distal, subtotal gastrectomy for advanced gastric cancer.

    PubMed

    Ben-David, Kfir; Tuttle, Rebecca; Kukar, Moshim; Oxenberg, Jacqueline; Hochwald, Steven N

    2015-02-01

    The objective of this study was to show laparoscopic subtotal, distal gastrectomy with D2 lymphadenectomy as a safe and appropriate method for the resection of advanced gastric cancer. This study was conducted at a designated NCI Cancer Center. Subjects of the study were patients with advanced gastric malignancy, including transmural penetration of the tumor and/or nodal disease, requiring subtotal, distal gastrectomy. The main outcome measure is a description of the technique of a laparoscopic subtotal, distal gastrectomy for antral and distal body tumors. In conclusion, the laparoscopic approach to advanced gastric malignancy with a subtotal, distal gastrectomy and D2 lymphadenectomy is a safe, oncologically appropriate procedure which provides excellent outcomes. PMID:25338659

  6. Continuous expression of slurry in a screw press

    SciTech Connect

    Shirato, M.; Hayashi, N.; Iwata, M.; Murase, T.; Ogawa, Y.

    1985-01-01

    An approximate method is described for predicting the steadystate performance of a screw press for the continuous expression of a slurry, with the worm channel being modified as the path between two flat plates. Screw expression of a slurry involves two mechanisms of dewatering which, for a batch operation, can be analyzed by the variable-pressure, variable-rate theory of filtration and by consolidation theory. By assuming that the expression consists of a succession of batch processes, basic equations are derived for the relationship between the dehydration rate, the feed rate, and the expression pressure distribution in a constant-pitch, straighttaper screw press. The thickness of the filter cake in the worm channel and the flow distribution in the consolidated cake are calculated for a given pressure distribution and feed rate, and the solids concentration and rate of discharge of the cake are estimated. The critical speed of rotation of the worm, at which the slurry becomes highly deliquored, is strongly influenced by the external diameter and helical angle of the worm. The theoretical results are in good agreement with experimental data for clay slurries with a concentration of 0.31-0.46 in the feed.

  7. Bone registration method for robot assisted surgery: pedicle screw insertion.

    PubMed

    Abdel-Malek, K; McGowan, D P; Goel, V K; Kowalski, D; Smith, S B

    1997-01-01

    A registration method that identifies bone geometry with respect to a robotic manipulator arm is presented. Although the method is generally applicable to many orthopaedic internal fixation procedures, it was only demonstrated for the insertion of pedicle screws in vertebral bodies for spine fixation. The method relies upon obtaining an impression of the vertebral bodies. Computerized tomography (CT) scans of both vertebrae and mould are reconstructed using a computer aided engineering (CAE) system. From the reconstructions, the surgeon is able to do preoperative planning including selection of pedicle screw diameter, direction of screw through pedicle, point of entry and length of engagement. The three-dimensional models are than meshed to determine positions of the surgeon's preoperative plan relative to the mould. Intra-operative positions are defined in space by a mechanical fixture rigidly attached to the mould and designed to allow a manipulator end-effector to recognize the global coordinates of the in vivo spine. The theory and methodology were validated using a five-axis manipulator arm. This initial presentation assumes and allows no relative motion between vertebrae in vivo. PMID:9255999

  8. The use of distal rhynchokinesis by birds feeding in water.

    PubMed

    Estrella, Sora M; Masero, José A

    2007-11-01

    The use of distal rhynchokinesis, which consists of the movement of the distal part of the upper jaw with respect to the cranium, is well documented in long-billed shorebirds (Scolopacidae), commonly being associated with the deep probing feeding method. However, the functional and evolutionary significance of distal rhynchokinesis and other cranial kinesis is unclear. We report for the first time the use and occurrence of distal rhynchokinesis in wild long-billed shorebirds feeding on small prey items suspended in water. We tested whether prey size in captive dunlins Calidris alpina influences the occurrence of distal rhynchokinesis during feeding and also whether its use affects foraging efficiency. We found that wild dunlin, curlew sandpiper Calidris ferruginea, sanderling Calidris alba and little stint Calidris minuta commonly use distal rhynchokinesis to strike, capture and transport small prey items. Prey size influenced the occurrence of distal rhynchokinesis during the transport phase, with this type of cranial kinesis being more frequently used with larger prey. The rhynchokinesis protraction angle (a measure of bill tip elevation) during prey strike and transport was affected by prey size, and bill gape was modulated through the use of distal rhynchokinesis in relation to prey size. Finally, the use of distal rhynchokinesis throughout intra-oral prey transport was related to shorter transport times, which improved foraging efficiency. We conclude that distal rhynchokinesis is a mechanism that could contribute to the flexible feeding behaviour of long-distance migratory shorebirds, enhancing small prey profitability and so improving foraging efficiency, and may have played a role in the evolutionary radiation of Scolopacidae (Charadrii). PMID:17951416

  9. Crystalline stereocomplexed polycarbonates: hydrogen-bond-driven interlocked orderly assembly of the opposite enantiomers.

    PubMed

    Liu, Ye; Ren, Wei-Min; Wang, Meng; Liu, Chuang; Lu, Xiao-Bing

    2015-02-01

    Four novel crystalline stereocomplexed polymers are formed by mixing isotactic (R)- and (S)-polycarbonates in 1:1 mass ratio. They show the enhanced thermal stability and new crystalline behavior, significantly distinct from the component enantiomer. Two stereocomplexed CO2 -based polycarbonates from meso-3,4-epoxytetrahydrofuran and 4,4-dimethyl-3,5,8-trioxabicyclo[5.1.0]octane have high melting temperatures of up to 300?°C, about 30?°C higher than the individual enantiomers. Isotactic (R)- or (S)-poly(cyclopentene carbonate) and poly(cis-2,3-butene carbonate) are typical amorphous polymeric materials, however, upon mixing both enantiomers together, a strong interlocked interaction between polymer chains of opposite configuration occurs, affording the crystalline stereocomplexes with melting temperatures of about 200?°C and 180?°C, respectively. A DFT study suggests that the driving force forming the stereocomplex is the hydrogen-bonding between carbonate units of the opposite enantiomers. PMID:25537626

  10. The community structure of the European network of interlocking directorates 2005-2010.

    PubMed

    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

  11. Venous Sac Embolization of Pulmonary Arteriovenous Malformation: Preliminary Experience Using Interlocking Detachable Coils

    SciTech Connect

    Takahashi, Koji [Department of Radiology, Asahikawa Medical College, 4-5-3-11 Nishikagura, Asahikawa, 078-8510 (Japan); Tanimura, Keiichi; Honda, Masanori [Department of Radiology, Saiseikai Utunomiya Hospital, 911-1 Takebayashi, Tochigi, 321 (Japan); Kikuno, Motoyuki [Department of Radiology, Takagi Hospital, 141-11 Sakami, Ohkawa, 831-0016 (Japan); Toei, Hisao; Hyodoh, Hideki; Furuse, Makoto [Department of Radiology, Jichi Medical School and Hospital, 3311-1 Yakushiji, Minamikawachi, Tochigi, 329-0498 (Japan); Yamada, Tomonori; Aburano, Tamio [Department of Radiology, Asahikawa Medical College, 4-5-3-11 Nishikagura, Asahikawa, 078-8510 (Japan)

    1999-05-15

    Purpose: To evaluate the indication and advantages of venous sac embolization of pulmonary arteriovenous malformations (PAVMs) using interlocking detachable coils (IDCs). Methods: We performed percutaneous embolization in 12 PAVMs in four patients using IDCs, initially placed in the venous sac or at the feeding artery to prevent systemic migration of additional coils. We placed the IDCs in the venous sac in PAVMs with the following vascular architecture: the draining vein was larger than the feeding arteries and both vessels were interposed with the venous sac or there were short feeding arteries. Results: Complete occlusion was achieved in all 12 PAVMs without significant complications. We deployed IDCs in the venous sac in eight PAVMs and in the feeding artery in four. Conclusion: Venous sac embolization may be beneficial in PAVMs with large out-flow vessels or short feeding arteries. IDCs are suitable for this procedure.

  12. An active interlock system for the NSLS x-ray ring insertion devices

    SciTech Connect

    Nawrocky, R.J.; Biscardi, R.; Dabrowski, J.; Flannigan, J.; Ramamoorthy, S.; Rothman, J.; Smith, J.; So, I.; Thomas, M. (Brookhaven National Lab., Upton, NY (USA)); Decker, G. (Argonne National Lab., IL (USA))

    1991-01-01

    This paper describes the design and operation of an active interlock system which has been installed in the NSLS X-ray electron storage ing to protect the vacuum chamber from thermal damage by mis-steered high power photon beams from insertion devices (IDs). the system employs active beam position detectors to monitor beam motion in the ID straight sections and solid state logic circuitry to dump'' the stored beam in the event of a fault condition by interrupting the rf. To ensure a high degree of reliability, redundancy and continuous automatic checking has been incorporated into the design. Overall system integrity is checked periodically with beam at safe levels of beam current. 2 refs., 3 figs.

  13. Experimental observation of extremely weak optical scattering from an interlocking carbon nanotube array.

    PubMed

    Yang, Zu-Po; Hsieh, Mei-Li; Bur, James A; Ci, Lijie; Hanssen, Leonard M; Wilthan, Boris; Ajayan, Pulickel M; Lin, Shawn-Yu

    2011-05-01

    We experimentally demonstrate a nearly wavelength-independent optical reflection from an extremely rough carbon nanotube sample. The sample is made of a vertically aligned nanotube array, is a super dark material, and exhibits a near-perfect blackbody emission at T=450 K-600 K. No other material exhibits such optical properties, i.e., ultralow reflectance accompanied by a lack of wavelength scaling behavior. This observation is a result of the lowest ever measured reflectance (R=0.0003) of the sample over a broad infrared wavelength of 3 ?m < ? < 13 ?m. This discovery may be attributed to the unique interlocking surface of the nanotube array, consisting of both a global, large scale and a short-range randomness. PMID:21532663

  14. Radiation interlocks: The choice between conventional hard-wired logic and computer-based systems

    SciTech Connect

    Crook, K.F.

    1986-11-01

    During the past few years, the use of computers in radiation safety systems has become more widespread. This is not surprising given the ubiquitous nature of computers in the modern technological world. But is a computer a good choice for the central logic element of a personnel safety system. Recent accidents at computer controlled medical accelerators would indicate that extreme care must be exercised if malfunctions are to be avoided. The Department of Energy has recently established a sub-committee to formulate recommendations on the use of computers in safety systems for accelerators. This paper will review the status of the committee's recommendations, and describe radiation protection interlock systems as applied to both accelerators and to irradiation facilities. Comparisons are made between the conventional relay approach and designs using computers. 6 refs., 6 figs.

  15. Doping Effect on Interlocked Ferroelectric and Structural Antiphase Domains in YMnO3

    NASA Astrophysics Data System (ADS)

    Kobayashi, Keisuke; Koyama, Tsukasa; Kamo, Hideki; Togawa, Yoshihiko; Horibe, Yoichi; Cheong, Sang Wook; Mori, Shigeo

    2012-09-01

    Changes in ferroelectric and structural antiphase domain structure by the partial substitution of nonmagnetic Ti4+ ions at the Mn site were investigated carefully by electron diffraction, dark-field imaging, and high-resolution lattice imaging experiments. The ferroelectric and structural antiphase domains are revealed to be mutually interlocked in YMnO3 and, on the other hand, when x was increased up to x˜0.30 in YMn1-xTixO3, the ferroelectric domains disappeared and the size of the structural antiphase domains decreased to approximately 10 nm at x˜0.30. High-resolution lattice images clearly demonstrate the coexisting state of nanodomains characterized by the modulated structure due to the structural trimerization and the nonmodulated structures. Our experimental results suggest that a partial substitution of Ti4+ ions suppressed the ferroelectric displacement along the [001] direction and the correlation length of the Mn3+ trimerization decreased.

  16. Distal Expression of knotted1 in Maize Leaves Leads to Reestablishment of Proximal/Distal Patterning and Leaf Dissection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize (Zea mays) leaves provide a useful system to study how proximal/distal patterning is established because of the distinct tissues found in the distal blade and the proximal sheath. Several mutants disrupt this pattern, including the dominant knotted1-like homeobox (knox) mutants. knox genes enc...

  17. External jig-aided intramedullary interlocking nailing of diaphyseal fractures: experience from a tropical developing centre.

    PubMed

    Ikpeme, Ikpeme; Ngim, Ngim; Udosen, Anthony; Onuba, Obiora; Enembe, Okokon; Bello, Segun

    2011-01-01

    Intramedullary interlocking nailing for diaphyseal fractures is a standard treatment option in affluent societies. These procedures are often performed under image intensifier guidance. The cost of these gadgets precludes their common use in resource poor regions. External jig-aided intramedullary interlocking nailing is relatively cheap and offers the chance for performing these procedures in resource poor regions. The aim of this study was to document the advantages, challenges and outcome of this form of treatment in a resource poor setting. The Surgical Implant Generation Network (SIGN) implants and instrumentation were used for this study. Thirty-seven limbs in 35 patients were included. There were 30 males and five females giving a ratio of 6:1. The mean age was 35?±?11.9 years with a range of 15-61 years. The femur and tibia were the bones studied with a total of 23 and 14 fractures, respectively (ratio 1.6:1). There were 14 comminuted fractures, two segmented fractures, six mal-unions, eight non-unions and seven simple fractures. Road traffic accidents were the most common cause of injuries with motorcycle accidents accounting for 19 (57.4%) cases. The mean follow-up period was 22?±?5.32 months, mean time to union was 16.9?±?5.4 weeks and the major complication was osteomyelitis (10.8%). We conclude that this is a viable treatment option for musculoskeletal injuries in resource poor regions. Education to encourage early acceptance of surgical intervention and reduced patronage of traditional bone setting for injudicious interventions can reduce the infective complication rates. PMID:20148329

  18. Imaging screw dislocations at atomic resolution by aberration-corrected electron optical sectioning

    PubMed Central

    Yang, H.; Lozano, J. G.; Pennycook, T. J.; Jones, L.; Hirsch, P. B.; Nellist, P. D.

    2015-01-01

    Screw dislocations play an important role in materials' mechanical, electrical and optical properties. However, imaging the atomic displacements in screw dislocations remains challenging. Although advanced electron microscopy techniques have allowed atomic-scale characterization of edge dislocations from the conventional end-on view, for screw dislocations, the atoms are predominantly displaced parallel to the dislocation line, and therefore the screw displacements are parallel to the electron beam and become invisible when viewed end-on. Here we show that screw displacements can be imaged directly with the dislocation lying in a plane transverse to the electron beam by optical sectioning using annular dark field imaging in a scanning transmission electron microscope. Applying this technique to a mixed [a+c] dislocation in GaN allows direct imaging of a screw dissociation with a 1.65-nm dissociation distance, thereby demonstrating a new method for characterizing dislocation core structures. PMID:26041257

  19. Research on energy conversion mechanism of a screw centrifugal pump under the water

    NASA Astrophysics Data System (ADS)

    Quan, H.; Li, R. N.; Su, Q. M.; Han, W.; Cheng, X. R.; Shen, Z. J.

    2013-12-01

    In order to research screw centrifugal pump impeller power capability and energy conversion mechanism, we used Navier-Stokes equation and standard k-? equation turbulence model on the basis of the Euler equations to carry out screw centrifugal pump internal flow numerical simulation. This was explored by simulating specific design conditions; the medium is water, variation of speed and pressure of flow filed under the action of the impeller, and the screw centrifugal impeller shroud line and wheel line segment take monitoring sites. The monitoring points are between dynamic head and static head change to analyze the energy conversion capability along the impeller corners of screw centrifugal pump. The results show that the energy of fluid of the screw centrifugal pump is provided by spiral segment, the spiral segment in front of the impeller has played a multi-level role, it has significant reference value to research the energy conversion mechanism of screw centrifugal pump under solid-liquid two phase.

  20. A technique for repairing a loosening abutment screw for a cement-retained implant prosthesis.

    PubMed

    Patil, Pravinkumar G

    2011-12-01

    Prostheses may be attached to implants or implant abutments using screw retention or cementation. With the increased use of cement-retained, implant-supported restorations for the replacement of missing teeth, clinicians may choose to use a definitive cement to lute the definitive restoration. Loosening of an abutment screw is a challenging complication of cement-retained, implant-supported prosthetic restorations. Often, the abutment screw becomes loose from the implant body, whereas the crown remains cemented to the abutment. In such situations, separating the cemented crown from the underlying abutment or locating the abutment-screw access for removal of the restoration is a difficult task. The purpose of this report is to describe a simple technique for locating the abutment-screw access in the event of its loosening. The advantage of this technique is that it can facilitate easy location of the abutment screw, thus minimizing damage to the existing restoration and allowing it to be reused. PMID:21883632

  1. Imaging screw dislocations at atomic resolution by aberration-corrected electron optical sectioning.

    PubMed

    Yang, H; Lozano, J G; Pennycook, T J; Jones, L; Hirsch, P B; Nellist, P D

    2015-01-01

    Screw dislocations play an important role in materials' mechanical, electrical and optical properties. However, imaging the atomic displacements in screw dislocations remains challenging. Although advanced electron microscopy techniques have allowed atomic-scale characterization of edge dislocations from the conventional end-on view, for screw dislocations, the atoms are predominantly displaced parallel to the dislocation line, and therefore the screw displacements are parallel to the electron beam and become invisible when viewed end-on. Here we show that screw displacements can be imaged directly with the dislocation lying in a plane transverse to the electron beam by optical sectioning using annular dark field imaging in a scanning transmission electron microscope. Applying this technique to a mixed [a+c] dislocation in GaN allows direct imaging of a screw dissociation with a 1.65-nm dissociation distance, thereby demonstrating a new method for characterizing dislocation core structures. PMID:26041257

  2. Does the anchorage form and depth influence the pull-out strength of screws from bone cement? An experimental study.

    PubMed

    Heller, K D; Zilkens, K W; Hammer, J; Cohen, B

    1997-01-01

    The pull-out strengths of cortical screws inserted into soft, unpolymerised Refobacin Palacos bone cement (procedure S) and into hardened polymerised cement into which a hole had been drilled and tapped (procedure P) were compared. Cortical screws 58 mm in length, outer diameter 4.5 mm and inner diameter 2.95 mm were used. Screws were inserted into cement cylinders at 5 mm incremental depths between 10 and 30 mm. At a screw depth of less than 25 mm, the screws pulled out, and at a depth of greater than 25 mm, the screws broke in both procedures. There was no statistically significant difference in pull-out strength leading to burst or break between the two procedures for screws inserted to comparable depths, but there was a statistically significant difference regarding the screwing depth regardless of the procedure of screw insertion chosen. The average material stability (sigma) of the cortical screws used was calculated to be 1191 N/mm2, and the elasticity limit was 5137 N. This study demonstrated that the material stability and not the depth of screw insertion was the limiting parameter in screw anchorage in bone cement while static testing. To avoid screw breakage due to fatigue during continuous alternate loading, the screws should not be loaded above this value. PMID:9006773

  3. Surgical Strategies to Improve Fixation in the Osteoporotic Spine: The Effects of Tapping, Cement Augmentation, and Screw Trajectory

    PubMed Central

    Kuhns, Craig A.; Reiter, Michael; Pfeiffer, Ferris; Choma, Theodore J.

    2013-01-01

    Study Design?Biomechanical study of pedicle screw fixation in osteoporotic bone. Objective?To investigate whether it is better to tap or not tap osteoporotic bone prior to placing a cement-augmented pedicle screw. Methods?Initially, we evaluated load to failure of screws placed in cancellous bone blocks with or without prior tapping as well as after varying the depths of tapping prior to screw insertion. Then we evaluated load to failure of screws placed in bone block models with a straight-ahead screw trajectory as well as with screws having a 23-degree cephalad trajectory (toward the end plate). These techniques were tested with nonaugmented (NA) screws as well as with bioactive cement (BioC) augmentation prior to screw insertion. Results?In the NA group, pretapping decreased fixation strength in a dose-dependent fashion. In the BioC group, the tapped screws had significantly greater loads to failure (p?screw orientation, the screws oriented at 23 degrees cephalad had a significantly higher failure force than their respective counterparts at 0 degrees (p?screw fixation is often inadequate in the osteoporotic spine, but this study suggests tapping prior to cement augmentation will substantially improve fixation when compared with not tapping. Angulating screws more cephalad also seems to enhance aging spine fixation. PMID:24494181

  4. Investigation on Kane dynamic equations based on screw theory for open-chain manipulators

    Microsoft Academic Search

    Liu Wu-fa; Gong Zhen-bang; Wang Qin-que

    2005-01-01

    First, screw theory, product of exponential formulas and Jacobian matrix are introduced. Then definitions are given about\\u000a active force wrench, inertial force wrench, partial velocity twist, generalized active force, and generalized inertial force\\u000a according to screw theory. After that Kane dynamic equations based on screw theory for open-chain manipulators have been derived.\\u000a Later on how to compute the partial velocity

  5. Hollow Mill for Extraction of Stripped Titanium Screws: An Easy, Quick, and Safe Technique

    PubMed Central

    Gupta, Ravi; Singh, Harpreet; Singh, Amit; Garg, Sudhir

    2014-01-01

    Removal of jammed titanium screws can be difficult due to the problem of stripping of the hexagonal heads of the screws. We present a technique of extraction of stripped screws with the use of a standard 4.5 mm stainless steel hollow mill in a patient of peri-implant fracture of the radius fixed with a titanium locking plate 2 years back. The technique is quick, safe, and cost effective. PMID:25013544

  6. [Jejunal pouch interposition and distal gastrectomy].

    PubMed

    Miwa, K; Kinami, S; Sahara, H; Matsumoto, H; Segawa, M; Michiwa, Y; Miyazaki, I

    1997-06-01

    We developed a new technique of reconstruction in Billroth 1 gastrectomy, jejunal pouch interposition (JPI). The interposed jejunal segment consists of a proximally double-plicated pouch and a distally isoperistaltic conduit. From 1987 to 1994, the JPI was performed on 102 patients with gastric carcinoma. The postoperative functional assay was carried out at least one year later after surgery. Sixty-five patients with the conventional Billroth 1 reconstruction (B-1) during the same period were employed as the control. Gastric emptying time estimated with scinti-scanning was significantly delayed in the JPI group compared with the B-1 group (p < 0.05). All individuals with JPI had meals three times a day whereas 13% of those with B-1 required those more than three times (p < 0.05). The incidence of dumping syndrome was significantly lower in the JPI group (6%) than the B-1 group (20%) (p < 0.05). The reflux of bile into the residual stomach was observed in the scintiscanning at 78% of patients with B-1 whereas 10% of those with JPI (p < 0.01). Endoscopy revealed that regurgitation gastritis was significantly decreased in the JPI group compared with that in the B-1 group (p < 0.01). These results suggest that the JPI prevents small stomach syndrome, dumping syndrome and alkaline reflux gastritis after the B-1 reconstruction. PMID:9255808

  7. Implant abutment screw reverse torque values before and after plasma cleaning.

    PubMed

    Micarelli, Costanza; Canullo, Luigi; Baldissara, Paolo; Clementini, Marco

    2013-01-01

    This in vitro study analyzed the reverse torque (RevT) of abutment screws following different cleaning treatments. A convenience sample of 50 customized titanium abutment screw complexes was divided into five groups: cleaning by steam (control group), cleaning by Argon plasma (test groups 1 and 2 [with chlorhexidine gel]), and replacement of old screws with new ones (test groups 3 and 4 [with chlorhexidine gel]). Abutments were screwed onto implants and tested for RevT. The RevT of the test groups was significantly higher than that of the control group. No statistically significant difference between test groups was noted except between groups 2 and 3. PMID:23837162

  8. Access to abutment screw in cement retained restorations: a clinical tip.

    PubMed

    Kheur, Mohit; Harianawala, Husain; Kantharia, Nidhi; Sethi, Tania; Jambhekar, Shantanu

    2015-02-01

    Abutment screw loosening has been reported to be the most common prosthetic complications occurring in screw retained as well as cement retained implant restorations. Different methods to treat this issue have been reported in the literature so far; however these have their own short-comings. Retrievability of an implant restoration intact becomes a clinical challenge when the restoration is cement retained especially with an angulated abutment. This technique is aimed at accurately determining the position of the abutment screw in 3 dimensional relationships using a vacuum formed clear stent. This technique can be used as a viable protocol for management of screw loosening in cement retained implant restorations. PMID:25859535

  9. Two-wave propagation in in vitro swine distal ulna

    NASA Astrophysics Data System (ADS)

    Mano, Isao; Horii, Kaoru; Matsukawa, Mami; Otani, Takahiko

    2015-07-01

    Ultrasonic transmitted waves were obtained in an in vitro swine distal ulna specimen, which mimics a human distal radius, that consists of interconnected cortical bone and cancellous bone. The transmitted waveforms appeared similar to the fast waves, slow waves, and overlapping fast and slow waves measured in the specimen after removing the surface cortical bone (only cancellous bone). In addition, the circumferential waves in the cortical bone and water did not affect the fast and slow waves. This suggests that the fast-and-slow-wave phenomenon can be observed in an in vivo human distal radius.

  10. An Asian Perspective on the Management of Distal Radius Fractures

    PubMed Central

    Sebastin, Sandeep J.; Chung, Kevin C.

    2012-01-01

    Synopsis There is little data with regards to the epidemiology, pathology, or management of distal radius fractures from centers in Asia. Asia includes five advanced economies, namely Hong Kong SAR, Japan, Korea, Singapore, and Taiwan and a number of emerging economies prominent among which are China, India, Malaysia, Philippines, and Thailand. This article examines the available epidemiological data from Asia, and compares the management of distal radius fractures in the advanced and emerging Asian economies and how they match up to the current management in the west. It concludes by offering solutions for improving outcomes of distal radius fractures in both the advanced and emerging economies of Asia. PMID:22554658

  11. Potassium transport across guinea pig distal colon

    SciTech Connect

    Rechkemmer, G.; Halm, D.R.; Frizzell, R.A.

    1986-03-05

    Active absorption and secretion of K was studied by measuring bidirectional /sup 42/K fluxes across short-circuited guinea pig distal colon. Tissues were pretreated with mucosal (m) and serosal (s) indomethacin (1 ..mu..M) and amiloride (0.1 mM, m) to suppress spontaneous, electrogenic Cl secretion and Na absorption. Under these conditions, the short-circuit current (I/sub sc/) was 0.4 ..mu..eq/cm/sup 2/h while electroneutral K absorption was 2.8 ..mu..eq/cm/sup 2/h. Epinephrine (5 ..mu..M, s) stimulated electrogenic K secretion, reducing net K absorption to 1.3 ..mu..eq/cm/sup 2/h. Bumetanide (0.1 mM, s) abolished this K secretion and restored K absorption to control values, suggesting mechanistic similarities between K and Cl secretion. K absorption was inhibited 40% by the gastric H/K ATPase inhibitor, omeprazole (0.1 mM, m), and was abolished by ouabain (0.1 mM, m). Neutral K absorption does not appear to be mediated by an apical membrane Na/K pump since: the effect of mucosal ouabain on K absorption does not require the presence of mucosal or serosal Na, unidirectional Na fluxes are not influenced by mucosal ouabain, and K absorption is not affected when Na absorption is abolished by amiloride. Net K transport is determined by the balance between electroneutral K absorption and electrogenic K secretion. The ouabain sensitivity of K absorption suggests that colonic H/K ATPase differs from its gastric counterpart.

  12. Crohn's disease of the distal ileum.

    PubMed Central

    Higgens, C S; Allan, R N

    1980-01-01

    A clinical and statistical analysis has been undertaken in a consecutive series of 227 patients with Crohn's disease involving the distal ileum under long-term review between 1944 and 1978. We have determined the long-term prognosis, cumulative reoperation rates after each resection, mortality rates, and their causes. Actuarial analysis has shown that the reoperation rates are similar after first, second, and third resections. There was no evidence that additional operations increase the risk of yet more resections. Reoperation rates were very little influenced by the age at diagnosis of the underlying Crohn's disease. A short interval from diagnosis of Crohn's disease to the first resection tended to increase the reoperation rate in the short term but there was no overall long-term effect. There was a two-fold increase in mortality risk when compared with the general population. Half the deaths were unrelated to the underlying Crohn's disease and, in this group, the incidence and causes were similar to those expected in the general population matched for age, sex, and years at risk. Of the disease related deaths many occurred in the early years of experience. Only four patients in the series have died of Crohn's disease in the last 10 years. One hundred and ninety-three patients are still alive after a mean interval of 16.1 years from the diagnosis of Crohn's disease. Full information is available on 185, of whom 161 are well and symptom free. Seven have minor problems, while 17 are unwell (nine with radiological evidence of recurrent disease). PMID:7450558

  13. A new alternative to expandable pedicle screws: Expandable poly-ether-ether-ketone shell.

    PubMed

    Demir, Teyfik

    2015-05-01

    Screw pullout is a very common problem in the fixation of sacrum with pedicle screws. The principal cause of this problem is that the cyclic micro motions in the fixation of sacrum are higher than the other regions of the vertebrae that limit the osteo-integration between bone and screw. In addition to that, the bone quality is very poor at sacrum region. This study investigated a possible solution to the pullout problem without the expandable screws' handicaps. Newly designed poly-ether-ether-ketone expandable shell and classical pedicle screws were biomechanically compared. Torsion test, pullout tests, fatigue tests, flexion/extension moment test, axial gripping capacity tests and torsional gripping capacity tests were conducted in accordance with ASTM F543, F1798 and F1717. Standard polyurethane foam and calf vertebrae were used as embedding medium for pullout tests. Classical pedicle screw pullout load on polyurethane foam was 564.8?N compared to the failure load for calf vertebrae's 1264?N. Under the same test conditions, expandable poly-ether-ether-ketone shell system's pullout loads from polyurethane foam and calf vertebrae were 1196.3 and 1890?N, respectively. The pullout values for expandable poly-ether-ether-ketone shell were 33% and 53% higher than classical pedicle screw on polyurethane foam and calf vertebrae, respectively. The expandable poly-ether-ether-ketone shell exhibited endurance on its 90% of yield load. Contrary to poly-ether-ether-ketone shell, classical pedicle screw exhibited endurance on 70% of its yield load. Expandable poly-ether-ether-ketone shell exhibited much higher pullout performance than classical pedicle screw. Fatigue performance of expandable poly-ether-ether-ketone shell is also higher than classical pedicle screw due to damping the micro motion capacity of the poly-ether-ether-ketone. Expandable poly-ether-ether-ketone shell is a safe alternative to all other expandable pedicle screw systems on mechanical perspective. PMID:25991716

  14. Oral Extrusion of Screw after Anterior Cervical Interbody Fusion

    PubMed Central

    Lee, Jin Soo; Hwang, Soo Hyun; Han, Jong Woo

    2008-01-01

    We present a case of delayed oral extrusion of a screw after anterior cervical interbody fusion in a 68-year-old man with osteoporosis. Fifteen months earlier, he had undergone C5 corpectomy and anterior cervical interbody fusion at C4-6 for multiple spinal stenoses. The patient was nearly asymptomatic, except for a foreign body sensation in his throat. We conclude that the use of a mesh graft or other instrument in elderly patients and those with osteoporosis or problematic bone quality should be considered carefully and that if surgery were to be performed, periodic postoperative follow-up evaluations are mandatory. PMID:19096688

  15. Helical rotary screw expanders to generate electricity from geothermal brines

    NASA Astrophysics Data System (ADS)

    1983-09-01

    A 1-megawatt, self-contained, helical rotary screw expander power plant to generate electricity of a geothermal brine wellhead was evaluated. The test support equipment, including a computer-controlled data system, an instrumentation and control van, and a 1000-kilowatt, variable bank were investigated. It was stated that the power was technically feasible although it operated at only about 45% average efficiency. Its technology transfer testing program involved Mexico, Italy, and New Zealand. The mineral laden geothermal brines of Mexico are more prone to scale formation than the Utah brine, and the power plant showed an increase in efficiency to a maximum of 62%.

  16. New Tools for Computational Geometry and Rejuvenation of Screw Theory

    NASA Astrophysics Data System (ADS)

    Hestenes, David

    Conformal Geometric Algebraic (CGA) provides ideal mathematical tools for construction, analysis, and integration of classical Euclidean, Inversive & Projective Geometries, with practical applications to computer science, engineering, and physics. This paper is a comprehensive introduction to a CGA tool kit. Synthetic statements in classical geometry translate directly to coordinate-free algebraic forms. Invariant and covariant methods are coordinated by conformal splits, which are readily related to the literature using methods of matrix algebra, biquaternions, and screw theory. Designs for a complete system of powerful tools for the mechanics of linked rigid bodies are presented.

  17. A description of the dynamics of manipulators using screw theory

    NASA Astrophysics Data System (ADS)

    Akselrod, B. V.

    1985-04-01

    The paper is concerned with the derivation of Lagrange equations of the second kind for a manipulator consisting of N links each of which is coupled with the preceding link (except for the first link, which is coupled with a fixed base) through a single-degree-of-freedom joint. The joints can be translational or rotational; each joint is treated as a rigid body, and the possibility of allowing for elasticity in the hinges and joints is demonstrated. The kinetic energy is determined using the theory of kinematic screws.

  18. The effect of screw preload and framework material on the success of cementable fixed partial prostheses: A finite element study.

    PubMed

    Hasan, Istabrak; Keilig, Ludger; Bourauel, Christoph; Lückerath, Walter

    2015-05-01

    The rigidity of framework materials and overload of the implant system directly affect the final transferred load of the bone around implants. The aim of the present study has been to analyse the influence of framework materials on the transferred load to the implant system and the surrounding bone. A finite element model of a long-span cementable implant-supported fixed prosthesis was created with two coping layers (gold and hybrid composite) to optimise the fitting of the prosthesis to the abutments. Three framework materials were analysed: titanium, gold alloy, and zirconia. The connection screws were first preloaded with 200N. The framework was then loaded with 500N vertically and at 30° to the framework long axis. Two loading conditions were considered: at the mesial and distal boundaries of the framework and at the centre of the framework. The stresses and strains within the framework materials and bone bed around the supporting implants were analysed. The region and angle of load applications showed an obvious effect on the values of the stresses and strains within the framework itself and, consequently, their distribution in the implant system and surrounding bone. A correlation of the framework material and stresses of the coping materials was observed as well. The gold framework showed acceptable values of stress within the cortical bone (92MPa and 89MPa with 30° loading at two points and at the centre, respectively) in comparison to titanium (92MPa and 113MPa) and zirconia (88MPa and 115MPa). PMID:24877686

  19. Split cord malformation type I distal to segmental myelomeningocele.

    PubMed

    Addas, Bassam M

    2014-12-01

    The coexistence of myelomeningocele (MMC) and split cord malformation (SCM) is a well-known phenomenon. The SCM is usually above or at the level of the MMC. Split cord malformation distal to the MMC is considered to be the rarest form of such a combination. We report a case of SCM (type I) distal to the MMC diagnosed pre-operatively. Repair of the MMC and the SCM were carried out in the same setting. PMID:25551117

  20. Radiographic Predictors of DRUJ Instability with Distal Radius Fractures

    PubMed Central

    Omokawa, Shohei; Iida, Akio; Fujitani, Ryotaro; Onishi, Tadanobu; Tanaka, Yasuhito

    2014-01-01

    Because the distal radioulnar joint (DRUJ) is an inherently unstable joint, the diagnosis and treatment of DRUJ instability is often difficult in a clinical hand surgery practice. Several soft tissue stabilizers are recognized, of which the deep limbs of the radioulnar ligament are primary stabilizers. This article discusses the predictors of DRUJ instability in distal radius fractures based on our clinical and biomechanical analyses. PMID:24533238

  1. Radiographic Predictors of DRUJ Instability with Distal Radius Fractures.

    PubMed

    Omokawa, Shohei; Iida, Akio; Fujitani, Ryotaro; Onishi, Tadanobu; Tanaka, Yasuhito

    2014-02-01

    Because the distal radioulnar joint (DRUJ) is an inherently unstable joint, the diagnosis and treatment of DRUJ instability is often difficult in a clinical hand surgery practice. Several soft tissue stabilizers are recognized, of which the deep limbs of the radioulnar ligament are primary stabilizers. This article discusses the predictors of DRUJ instability in distal radius fractures based on our clinical and biomechanical analyses. PMID:24533238

  2. Extended distal pancreatectomy for advanced pancreatic neck cancer

    PubMed Central

    Park, Shin-Young; Shin, Woo Young; Choe, Yun-Mee; Ahn, Seung-Ik

    2014-01-01

    Backgrounds/Aims We investigated the clinical application of extended distal pancreatectomy in patients with pancreatic neck cancer accompanied by distal pancreatic atrophy. In this study, we have emphasized on the technical aspects of using the linear stapling device for a bulky target organ. Methods From March 2010 to September 2013, 46 patients with pancreatic adenocarcinoma, who underwent pancreatic resection with radical intent at our institute, were reviewed retrospectively. Among them, three patients (6.5%) underwent extended distal pancreatectomy. A linear stapling device and vise-grip locking pliers were used for en bloc resection of the distal pancreas, first duodenal portion, and distal common bile duct. The results were compared with those after standard pancreatectomy. Results All three patients presented with jaundice, and the ratio of pancreatic duct to parenchymal thickness of the pancreatic body was greater than 0.5. Grade A pancreatic fistula developed in all of the cases, but none of these fistulae were lethal. Pathological staging was T3N1M0 in all of the patients. The postoperative daily serum glucose fluctuations and insulin requirements were comparable to those in patients who received pancreaticoduodenectomy or distal pancreatectomy. At the last follow-up, two patients were alive with liver metastasis at 4 and 10 months postoperatively, respectively, and one patient died of liver metastasis at 5 months postoperatively. Conclusions While the prognosis of advanced pancreatic neck adenocarcinoma is still dismal, extended distal pancreatectomy is a valid treatment option, especially when there is atrophy of the distal pancreas. Also, the procedure is technically feasible, and further refinement is necessary to improve patient survival.

  3. Endovascular treatment for ruptured distal anterior inferior cerebellar artery aneurysm.

    PubMed

    Oh, Jae-Sang; Yoon, Seok-Mann; Shim, Jai-Joon; Bae, Hack-Gun; Yoon, Il-Gyu

    2014-03-01

    A 42-year-old woman presented with Hunt and Hess grade (HHG) III subarachnoid hemorrhage (SAH) caused by a ruptured left distal anterior inferior cerebellar artery (AICA) aneurysm. Computed tomography showed a thin SAH on the cerebellopontine angle cistern, and small vermian intracerebral hemorrhage and intraventricular hemorrhage in the fourth ventricle. Digital subtraction angiography revealed the aneurysm on the postmeatal segment of left distal AICA, a branching point of rostrolateral and caudomedial branch of the left distal AICA. Despite thin caliber, tortuous running course and far distal location, the AICA aneurysm was obliterated successfully with endovascular coils without compromising AICA flow. However, the patient developed left side sensorineural hearing loss postoperatively, in spite of definite patency of distal AICA on the final angiogram. She was discharged home without neurologic sequela except hearing loss and tinnitus. Endovascular treatment of distal AICA aneurysm, beyond the meatal loop, is feasible while preserving the AICA flow. However, because the cochlear hair cell is vulnerable to ischemia, unilateral hearing loss can occur, possibly caused by the temporary occlusion of AICA flow by microcatheter during endovascular treatment. PMID:24765609

  4. Endovascular Treatment for Ruptured Distal Anterior Inferior Cerebellar Artery Aneurysm

    PubMed Central

    Oh, Jae-Sang; Shim, Jai-Joon; Bae, Hack-Gun; Yoon, Il-Gyu

    2014-01-01

    A 42-year-old woman presented with Hunt and Hess grade (HHG) III subarachnoid hemorrhage (SAH) caused by a ruptured left distal anterior inferior cerebellar artery (AICA) aneurysm. Computed tomography showed a thin SAH on the cerebellopontine angle cistern, and small vermian intracerebral hemorrhage and intraventricular hemorrhage in the fourth ventricle. Digital subtraction angiography revealed the aneurysm on the postmeatal segment of left distal AICA, a branching point of rostrolateral and caudomedial branch of the left distal AICA. Despite thin caliber, tortuous running course and far distal location, the AICA aneurysm was obliterated successfully with endovascular coils without compromising AICA flow. However, the patient developed left side sensorineural hearing loss postoperatively, in spite of definite patency of distal AICA on the final angiogram. She was discharged home without neurologic sequela except hearing loss and tinnitus. Endovascular treatment of distal AICA aneurysm, beyond the meatal loop, is feasible while preserving the AICA flow. However, because the cochlear hair cell is vulnerable to ischemia, unilateral hearing loss can occur, possibly caused by the temporary occlusion of AICA flow by microcatheter during endovascular treatment. PMID:24765609

  5. Distal attribution and distance perception in sensory substitution.

    PubMed

    Siegle, Joshua H; Warren, William H

    2010-01-01

    In sensory substitution, the user may be directly aware of distal objects, as in everyday perception, or make explicit cognitive inferences based on an awareness of the proximal stimulation. Anecdotal evidence supports the experience of distal attribution, but so far there have been few rigorous experimental tests of the claim. In this study, blindfolded participants observed a target light using a device consisting of a finger-mounted photodiode that drives tactile vibra-tion on the back. With the blindfold off and the target removed, participants moved a reference object to match the perceived egocentric distance of the target. Participants who were instructed to attend to the distal target improved significantly during 2 h of practice, whereas those instructed to attend to proximal variables showed no improvement. Unsigned error increased with ratings of proximal attention, but decreased with ratings of target object solidity, consistent with distal attribution. Performance transferred to the non-dominant arm and to a rotated body orientation, demonstrating that learning did not depend on a joint-specific sensorimotor relationship between target distance and arm configuration. The results experimentally confirm that distal attribution can occur in sensory substitution, based on a perceptual strategy rather than an explicit cognitive strategy. Moreover, they suggest that the informational basis for distal attribution is not a joint-specific sensorimotor relation, but a more abstract spatial invariant. PMID:20402243

  6. Primary ciliogenesis requires the distal appendage component Cep123

    PubMed Central

    Sillibourne, James E.; Hurbain, Ilse; Grand-Perret, Thierry; Goud, Bruno; Tran, Phong; Bornens, Michel

    2013-01-01

    Summary Primary cilium formation is initiated at the distal end of the mother centriole in a highly co-ordinated manner. This requires the capping of the distal end of the mother centriole with a ciliary vesicle and the anchoring of the basal body (mother centriole) to the cell cortex, both of which are mediated by the distal appendages. Here, we show that the distal appendage protein Cep123 (Cep89/CCDC123) is required for the assembly, but not the maintenance, of a primary cilium. In the absence of Cep123 ciliary vesicle formation fails, suggesting that it functions in the early stages of primary ciliogenesis. Consistent with such a role, Cep123 interacts with the centriolar satellite proteins PCM-1, Cep290 and OFD1, all of which play a role in primary ciliogenesis. These interactions are mediated by a domain in the C-terminus of Cep123 (400–783) that overlaps the distal appendage-targeting domain (500–600). Together, the data implicate Cep123 as a new player in the primary ciliogenesis pathway and expand upon the role of the distal appendages in this process. PMID:23789104

  7. Retrograde Intramedullary Nailing for Distal Femur Fracture with Osteoporosis

    PubMed Central

    Kim, Jihyeung; Nam, Kyungpyo; Rhee, Seung Hwan; Won, Jong Won; Han, Hyuk-Soo

    2012-01-01

    Background The incidence of distal femur fracture in the elderly has been increasing recently, and commonly occurs with osteoporosis. Retrograde intramedullary nailing has been considered a good surgical option for distal femur fracture. The purpose of the present study was to present our surgical results with retrograde intramedullary nailing for distal femur fractures with osteoporosis. Methods Thirteen patients diagnosed with extra-articular distal femur fracture and osteoporosis and managed with retrograde intramedullary nailing were retrospectively reviewed. Cement augmentation was used in four patients, shape memory alloy was used in eight patients and both were used in one patient. All patients were followed up for more than 2 years. Radiologic alignments were scored and Tegner and the Lysholm activity score was used for a functional assessment. Results The average time to clinical union was 13 weeks (range, 10 to 15 weeks). In 12 of our cases, the total alignment scores were excellent. At the last follow-up, the mean range of motion was 116° (range, 110° to 125°). The average functional score at postoperative 1 year was 2.6 (range, 1 to 5). Conclusions Retrograde intramedullary nailing is a good surgical option for distal femur fracture with osteoporosis. Cement augmentation and shape memory alloy can also be used for added mechanical stability. This surgical technique is very useful for distal femur fracture with osteoporosis as it promotes fracture healing and early rehabilitation. PMID:23205241

  8. Determining the residence time distribution of various screw elements in a co-rotating twin-screw extruder by means of fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Lepschi, Alexander; Gerstorfer, Gregor; Miethlinger, Jürgen

    2015-05-01

    The Residence Time Distribution (RTD) is key to optimizing the mixing ability of an extruder. For both sensitive and reactive materials, it is important to know how long particles remain in the barrel and how long the polymer remains, for instance, in a kneading element. To assess the influence of different screw configurations on the RTD, a low-concentration tracer particle was injected into the feeding section and measured inline by fluorescence spectroscopy1 both inside the barrel and at the extruder exit. The measurements were conducted using polypropylene with different amounts of organic peroxide. Measuring the residence time at various positions along the screw allows the RTD to be determined for just one screw element. Furthermore, we show the influence of different screw configurations on the polydispersity of polypropylene.

  9. FEM simulation of 3D angle-interlock woven composite under ballistic impact from unit cell approach

    Microsoft Academic Search

    Zhijiang Li; Baozhong Sun; Bohong Gu

    2010-01-01

    Ballistic impact damage of 3D angle-interlock woven composite (3DAWC) under a hemispherical-cylindrical steel projectile has been investigated in experimental and finite element method (FEM) based on a unit cell model. In the unit cell model, the composite was simplified into a combination of resins, weft yarns and warp yarns to define the stiffness matrix and failure evolution of the material.

  10. Fabrication of a screw-retained fixed provisional prosthesis supported by dental implants

    Microsoft Academic Search

    Ali Murat Kökat; K?vanç Akça

    2004-01-01

    Screw-retained provisional implant-supported prostheses may have advantages over cement-retained prostheses in certain situations. This article describes a technique for fabrication of screw-retained provisional acrylic resin implant-supported prostheses from the modified metal components provided with the implant.

  11. Value Proposition: Previous physical limitations of use of the screw pump

    E-print Network

    Haller-Dintelmann, Robert

    Value Proposition: · Previous physical limitations of use of the screw pump technology do not apply drive Field of Application: The technology is interesting for all pump manufacturers, who supply pumps the functionality of the screw pump State of the art: · Pressure operation limit is function of rotating speed, oil

  12. Transarticular screw fixation for atlantoaxial instability - modified Magerl's technique in 38 patients

    Microsoft Academic Search

    Raj Bahadur; Tarun Goyal; Saravdeep S Dhatt; Sujit K Tripathy

    2010-01-01

    BACKGROUND: Symptomatic atlantoaxial instability needs stabilization of the atlantoaxial joint. Among the various techniques described in literature for the fixation of atlantoaxial joint, Magerl's technique of transarticular screw fixation remains the gold standard. Traditionally this technique combines placement of transarticular screws and posterior wiring construct. The aim of this study is to evaluate clinical and radiological outcomes in subjects of

  13. Theoretical analysis of screw dislocations and image forces in anisotropic multilayered media

    NASA Astrophysics Data System (ADS)

    Ma, Chien-Ching; Lu, Hsin-Tai

    2006-04-01

    The elastic field induced by a screw dislocation embedded in an anisotropic elastic multilayered medium is presented in this study. A linear coordinate transformation is introduced in this study to simplify the problem. The explicit complete solutions of shear stresses and displacement for this problem consist only of the simplest solutions for a screw dislocation in an infinite homogeneous medium. The physical meaning of the solution is the image method and the magnitudes and locations of image screw dislocations are determined automatically from the mathematical method presented in this study. With the aid of the Peach-Koehler equation, the explicit forms of image forces exerted on screw dislocations are easily derived from the full-field solutions of stresses. Numerical results for full-field stress distributions in multilayered media subjected to a screw dislocation are presented. The image forces and equilibrium positions of a screw dislocation, two screw dislocations, and an array of screw dislocations are presented by numerical calculations and are discussed in detail.

  14. Application of screw theory to motion analysis of assemblies of rigid parts

    Microsoft Academic Search

    Jeffrey D. Adams; Salvatore Gerbino; Daniel E. Whitney

    1999-01-01

    Screw theory is well known to do kinematic computations. Recently it has been used to create kinematic models of assembly features so allowing assembly analysis. Motion limit analysis uses the mathematics of screw theory to model the ability of mechanical assembly features to allow or constrain rigid body motions in six degrees of freedom. A user of this theory is

  15. Depinning transition for a screw dislocation in a model solid solution S. Patinet and L. Proville

    E-print Network

    Paris-Sud XI, Université de

    Depinning transition for a screw dislocation in a model solid solution S. Patinet and L. Proville: November 2, 2008) On the basis of the classical dislocation theory, the solid solution hardening (SSH associated with a screw dislocation in a random Ni(Al) single crystal has same order as the edge one

  16. The effect of Dirac phase on acoustic vortex in media with screw dislocation

    NASA Astrophysics Data System (ADS)

    Torabi, Reza; Rezaei, Zahra

    2013-10-01

    We study acoustic vortex in media with screw dislocation using the Katanaev-Volovich theory of defects. It is shown that the screw dislocation affects the beam's orbital angular momentum and changes the acoustic vortex strength. This change is a manifestation of topological Dirac phase and is robust against fluctuations in the system.

  17. A lattice-dynamics model of an oscillating screw dislocation N. E. Glass (*)

    E-print Network

    Paris-Sud XI, Université de

    741 A lattice-dynamics model of an oscillating screw dislocation N. E. Glass (*) Institut de génie-force, or Kanzaki force, for a static screw dislocation is extended to describe a moving dislocation 2014. In the case of dislocation statics, the inadequacy of linear elastic continuum-theory to describe the core

  18. Peierls stress of a screw dislocation in a piezoelectric medium Shaofan Lia)

    E-print Network

    Li, Shaofan

    Peierls stress of a screw dislocation in a piezoelectric medium Shaofan Lia) and Anurag Gupta to describe dislocation mobility in piezoelectric materials. The Peierls stress of a screw dislocation in a piezoelectric material is calculated based on the generalized PN model and linear piezoelectricity theory

  19. Calculating possible local displacement of curve objects using improved screw theory

    Microsoft Academic Search

    Jun Takamatsu; Koichi Ogawara; Hiroshi Kimura; Katsushi Ikeuchi

    2003-01-01

    Various methods to recognize assembly tasks using possible local displacement of objects have been pro- posed. To calculate this displacement, the screw theory is employed. It is equivalent to the first order Taylor expansion of the displacement. However, such methods can treat polyhedral objects only. Because the screw theory cannot treat curvature information of objects. In this paper, we propose

  20. Experimental evidence for helical instability of screw dislocation lines in a smectic A phase

    E-print Network

    Paris-Sud XI, Université de

    L-319 Experimental evidence for helical instability of screw dislocation lines in a smectic A phase of helical instabilities of the screw dislocations which, although metastable, are always present of the sample. Experiment matches with the theory developed in [9] for static deformations and extended here

  1. Lumbosacral fixation using sacroiliac buttress screws: a modification to the Jackson technique with intrasacral rods

    PubMed Central

    2014-01-01

    Background The use of intrasacral rods has been previously reported for posterior lumbosacral fixation. However, problems associated with this technique include poor stability of the rod in the sacrum, difficulty in contouring the rod to fit the lateral sacral mass, and the complicated assembly procedure for the rod and pedicle screws in the thoracolumbar segments after insertion of the rod into the sacrum. Methods We used a screw with a polyaxial head instead of an intrasacral rod, which was inserted into the lateral sacral mass and assembled to the rod connected cephalad to pedicle screws. The dorsal side of the screw was stabilized by the sacral subchondral bone at the sacroiliac joint with iliac buttress coverage, and the tip of the screw was anchored by the sacral cortex. Results Three different cases were used to illustrate lumbosacral fixation using intrasacral screws as an anchor for the spinal instrumentation. Effective resistance of flexural bending moment and fusion were achieved in these patients at the lumbosacral level. Conclusions An intrasacral screw can be stabilized by subchondral bone with iliac buttress coverage at the dorsal and ventral sacral cortex. Posterior spinal fusion with this screw technique enables easier assembly of the instrumentation and presents better stabilization than that provided by the previously reported intrasacral rod technique for correction and fusion of thoracolumbar kyphoscoliosis. PMID:25050132

  2. Non-invasive ultrasound based temperature measurements at reciprocating screw plastication units: Methodology and applications

    NASA Astrophysics Data System (ADS)

    Straka, Klaus; Praher, Bernhard; Steinbichler, Georg

    2015-05-01

    Previous attempts to accurately measure the real polymer melt temperature in the screw chamber as well as in the screw channels have failed on account of the challenging metrological boundary conditions (high pressure, high temperature, rotational and axial screw movement). We developed a novel ultrasound system - based on reflection measurements - for the online determination of these important process parameters. Using available pressure-volume-temperature (pvT) data from a polymer it is possible to estimate the density and adiabatic compressibility of the material and therefore the pressure and temperature depending longitudinal ultrasound velocity. From the measured ultrasonic reflection time from the screw root and barrel wall and the pressure it is possible to calculate the mean temperature in the screw channel or in the chamber in front of the screw (in opposition to flush mounted infrared or thermocouple probes). By means of the above described system we are able to measure axial profiles of the mean temperature in the screw chamber. The data gathered by the measurement system can be used to develop control strategies for the plastication process to reduce temperature gradients within the screw chamber or as input data for injection moulding simulation.

  3. Investigation of a Multiphase Twin-screw Pump Operating at High Gas Volume Fractions 

    E-print Network

    Kroupa, Ryan Daniel

    2012-07-16

    The use of twin-screw pumps for moving fluids is not new technology but its application to wet gas compression (high gas volume fraction [GVF]) is still considered relatively new. There are many advantages for using twin-screw pumps for oil field...

  4. Interaction between a screw dislocation and an elastic elliptical inhomogeneity with interfacial cracks

    Microsoft Academic Search

    Qihong Fang; Youwen Liu; Chiping Jiang

    2005-01-01

    The elastic interaction between a screw dislocation and an elliptical inhomogeneity with interfacial cracks is studied. The screw dislocation may be located outside or inside the inhomogeneity. An efficient complex variable method for the complex multiply connected region is developed, and the general solutions to the problem are derived. As illustrative examples, solutions in explicit series form for complex potentials

  5. Three-dimensional location of the retaining screw axis for a cemented single tooth implant restoration.

    PubMed

    Wicks, Russell; Shintaku, Werner H; Johnson, Andrew

    2012-08-01

    Retrievability is a major concern with cemented versus screw-retained implant restorations. This article describes the use of cone beam radiography to help target and create a precise screw access opening for a loosened implant-supported single crown retained by cement to its abutment. PMID:22823426

  6. A method for restoring facially inclined implants with a screw-retained restoration.

    PubMed

    Takanashi, Kazunari; Lee, Joung Min; Sedler, Anatoly; Aalam, Alina Krivitsky

    2013-04-01

    Cement-retained implant restorations have 2 major disadvantages: they have a submucosal cement line and the prosthesis is difficult to retrieve. Although a screw-retained implant restoration negates both of these concerns, anatomic limitations can hinder its use. This article describes a simple technique for restoring a buccally inclined dental implant with a screw-retained restoration. PMID:23566609

  7. Initial fixation strength of polylactic acid interference screws in anterior cruciate ligament reconstruction

    Microsoft Academic Search

    JA Abate; PD Fadale; MJ Hulstyn; WR Walsh

    1998-01-01

    The initial fixation properties of bioresorbable polylactic acid (PLA) interference screws designed for anterior cruciate ligament reconstruction were evaluated using an in vitro bovine model. The surgical technique of interference screw fixation of the bone-patellar tendon-bone autograft complex performed clinically was reproduced in an adult bovine model. The reconstructed knee was tested oriented in 30 degrees of flexion to allow

  8. 29 CFR 1926.305 - Jacks-lever and ratchet, screw, and hydraulic.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Labor 8 2014-07-01 2014-07-01 false Jacks-lever and ratchet, screw, and hydraulic. 1926.305 Section...CONSTRUCTION Tools-Hand and Power § 1926.305 Jacks—lever and ratchet, screw, and hydraulic. (a) General...

  9. 29 CFR 1926.305 - Jacks-lever and ratchet, screw, and hydraulic.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Labor 8 2013-07-01 2013-07-01 false Jacks-lever and ratchet, screw, and hydraulic. 1926.305 Section...CONSTRUCTION Tools-Hand and Power § 1926.305 Jacks—lever and ratchet, screw, and hydraulic. (a) General...

  10. 29 CFR 1926.305 - Jacks-lever and ratchet, screw, and hydraulic.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Labor 8 2011-07-01 2011-07-01 false Jacks-lever and ratchet, screw, and hydraulic. 1926.305 Section...CONSTRUCTION Tools-Hand and Power § 1926.305 Jacks—lever and ratchet, screw, and hydraulic. (a) General...

  11. 29 CFR 1926.305 - Jacks-lever and ratchet, screw, and hydraulic.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Labor 8 2012-07-01 2012-07-01 false Jacks-lever and ratchet, screw, and hydraulic. 1926.305 Section...CONSTRUCTION Tools-Hand and Power § 1926.305 Jacks—lever and ratchet, screw, and hydraulic. (a) General...

  12. Application of FRP screw anchor and geosynthetics in repairing of canal slope of expansive soils

    Microsoft Academic Search

    Wang Xiequn; Lu Jianwei; Wang Zhao

    2010-01-01

    The application of FRP screw anchor, geogrid, geofoam slab and geosynthetics clay liner (GCL) in repairing slide of canal slope of expansive soils has been introduced in this paper. The FRP screw anchor was used to anchor the concrete frame girder above the berm and concrete slab below the beam, the geogrid improved the factor of safety against complete sliding

  13. Theoretical study of kinks on screw dislocation in silicon

    NASA Astrophysics Data System (ADS)

    Pizzagalli, L.; Pedersen, A.; Arnaldsson, A.; Jónsson, H.; Beauchamp, P.

    2008-02-01

    Theoretical calculations of the structure, formation, and migration of kinks on a nondissociated screw dislocation in silicon have been carried out using density functional theory calculations as well as calculations based on interatomic potential functions. The results show that the structure of a single kink is characterized by a narrow core and highly stretched bonds between some of the atoms. The formation energy of a single kink ranges from 0.9to1.36eV , and is of the same order as that for kinks on partial dislocations. However, the kinks migrate almost freely along the line of an undissociated dislocation unlike what is found for partial dislocations. The effect of stress has also been investigated in order to compare with previous silicon deformation experiments which have been carried out at low temperature and high stress. The energy barrier associated with the formation of a stable kink pair becomes as low as 0.65eV for an applied stress on the order of 1GPa , indicating that displacements of screw dislocations likely occur via thermally activated formation of kink pairs at room temperature.

  14. EMA 611 Advanced Mechanical Testing of Materials, University of Wisconsin Experiment 1: Tests with screw-driven testing machines

    E-print Network

    Lakes, Roderic

    with screw-driven testing machines Pre-lab assignment Review your prior work (if any) with the screw of the test frame. If it is necessary to change grips make sure to tighten the collar toward the screw end Discuss your results, their implications, and comparison with theory. §7 Questions Answers should go

  15. Hydroxyapatite and fluorapatite coatings on dental screws: effects of blast coating process and biological response.

    PubMed

    Dunne, Conor F; Twomey, Barry; Kelly, Ciara; Simpson, Jeremy C; Stanton, Kenneth T

    2015-01-01

    This paper describes the deposition of hydroxyapatite (HA) and fluorapatite (FA) onto titanium dental screws using a novel ambient temperature coating technique named CoBlast. The process utilises a coating medium and a blast medium sprayed simultaneously at the substrate surface. The blast medium was a sintered apatite (sHA) and two particles sizes (<106 and <180 µm) were used to assess their influence on the coating process. The influence of the coating process on the coating composition, coating adhesion, screw morphology and screw microstructure was examined. XRD analysis revealed the coating crystallinity was the same as the original HA and FA feedstock powders. Examining the screw's morphology, the threads of the CoBlasted screws exhibited rounding compared to the unmodified screw. This is due to the abrasive nature of the CoBlast process. The degree of rounding was more significant for the screws blasted with the 180 µm sHA than the 106 µm sHA. The blast media particle size significantly influences the surface roughness of both the substrate and coating and the microstructure of the substrate. The screws did not exhibit any loss of coating after insertion into a model bone material, indicating that the coating was strongly adhered to the substrate. There was no statistically significant difference in cell attachment and cell morphology on the unmodified substrates compared to the coated substrates. In conclusion, the CoBlast process can be used to deposit HA and FA onto complex geometries such as dental screws. The choice of blast medium particle size influences the screws morphology. The coating process does not negatively impact on the cell attachment and morphology in vitro. PMID:25578701

  16. Validation of an improved method to calculate the orientation and magnitude of pedicle screw bending moments.

    PubMed

    Freeman, Andrew L; Fahim, Mina S; Bechtold, Joan E

    2012-10-01

    Previous methods of pedicle screw strain measurement have utilized complex, time consuming methods of strain gauge application, experience high failure rates, do not effectively measure resultant bending moments, and cannot predict moment orientation. The purpose of this biomechanical study was to validate an improved method of quantifying pedicle screw bending moment orientation and magnitude. Pedicle screws were instrumented to measure biplanar screw bending moments by positioning four strain gauges on flat, machined surfaces below the screw head. Screws were calibrated to measure bending moments by hanging certified weights a known distance from the strain gauges. Loads were applied in 30?deg increments at 12 different angles while recording data from two independent strain channels. The data were then analyzed to calculate the predicted orientation and magnitude of the resultant bending moment. Finally, flexibility tests were performed on a cadaveric motion segment implanted with the instrumented screws to demonstrate the implementation of this technique. The difference between the applied and calculated orientation of the bending moments averaged (±standard error of the mean (SEM)) 0.3?±?0.1?deg across the four screws for all rotations and loading conditions. The calculated resultant bending moments deviated from the actual magnitudes by an average of 0.00?±?0.00 Nm for all loading conditions. During cadaveric testing, the bending moment orientations were medial/lateral in flexion-extension, variable in lateral bending, and diagonal in axial torsion. The technique developed in this study provides an accurate method of calculating the orientation and magnitude of screw bending moments and can be utilized with any pedicle screw fixation system. PMID:23083202

  17. Supervision Software for the Integration of the Beam Interlock System with the CERN Accelerator Complex

    E-print Network

    Audrain, M; Dragu, M; Fuchsberger, K; Garnier, JC; Gorzawski, AA; Koza, M; Krol, K; Moscatelli, A; Puccio, B; Stamos, K; Zerlauth, M

    2014-01-01

    The Accelerator complex at the European Organisation for Nuclear Research (CERN) is composed of many systems which are required to function in a valid state to ensure safe beam operation. One key component of machine protection, the Beam Interlock System (BIS), was designed to interface critical systems around the accelerator chain, provide fast and reliable transmission of beam dump requests and trigger beam extraction in case of malfunctioning of equipment systems or beam losses. Numerous upgrades of accelerator and controls components during the Long Shutdown 1 (LS1) are followed by subsequent software updates that need to be thoroughly validated before the restart of beam operation in 2015. In parallel, the ongoing deployments of the BIS hardware in the PS booster (PSB) and the future LINAC4 give rise to new requirements for the related controls and monitoring software due to their fast cycle times. This paper describes the current status and ongoing work as well as the long-term vision for the integratio...

  18. 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.

  19. 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. PMID:23202575

  20. 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

  1. 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.

  2. Spleen-Preserving Distal Pancreatectomy for Pancreatic Trauma: A Series of Six Cases

    Microsoft Academic Search

    Thakur Deen Yadav; Sabareesh Kumar Natarajan; Venkata Murali; Gottapu Kishore

    Context Spleen-preserving distal pancreatectomy is a well-accepted procedure for benign tumors of the distal pancreas. Its safety and feasibility have been proven. However many doctors have not used this procedure due to the trauma involved. Objective We present our experience of six cases of distal pancreatic trauma where we managed to preserve the spleen during distal pancreatectomy in an emergency

  3. When Planning Screw Fracture Fixation Why the 5.5?mm Screw is the Goldilocks Screw. An Observational Computer Tomographic Study of Fifth Metatarsal Bone Anatomy in a Sample of Patients.

    PubMed

    Iselin, Lukas D; Ramawat, Sunil; Hanratty, Brian; Klammer, Georg; Stavrou, Peter

    2015-05-01

    We wanted to verify our clinical experience that the 5.5?mm screw was ideal in the majority of fifth metatarsal fracture fixation. The size of a screw is important for the successful surgical treatment of these fractures in order to obtain the maximal stability while reducing the risk for iatrogenic fracture.A sample of patients undergoing computer tomographic imaging of the foot for investigation other than fifth metatarsal pathology were recruited. The parameters of the fifth metatarsal bone anatomy were measured.These parameters of the 5.5?mm screw were correlated with this data. The upper parameter (the diameter of the threads) was 5.5 and the lower parameter (the diameter of the shank) was 4.0?mm.Twenty seven patients were recruited.The proximal third internal diameter ranged from 3.6 to 7.0?mm with a mean of 5.0?mm. 93% of the metatarsals could easily accommodate the 5.5?mm screw. Two of the metatarsals had an internal diameter of < 4?mm (7%).It is our belief that the 5.5?mm screw may be used safely in the majority of patients with fifth metatarsal fractures. PMID:25950685

  4. Minimally Invasive Surgical Fixation of Distal Radius Fractures

    Microsoft Academic Search

    Phani K. Dantuluri

    \\u000a The advent of improved surgical instrumentation and advances in healthcare have driven the rapidly evolving field of orthopedics.\\u000a There has been a trend toward minimally invasive surgery in order to improve cosmesis, minimize soft tissue trauma, and allow\\u000a superior fracture healing by minimally disturbing the biological environment around the fracture. Minimally invasive joint\\u000a replacement surgery, arthroscopic surgery, and locking screw

  5. [Experimental study on the effects of cage-squeezing screw on tendon-bone healing in a rabbit model].

    PubMed

    Zhang, Qingxiang; Zhang, Ping; Lu, Xiping

    2011-06-01

    This investigation was to study the effects of cage-squeezing screw on tendon-bone healing in rabbits. The tendons of Twenty four rabbits were severed and fixed with cage-squeezing screw or ordinary squeezing screw on its tibia, and the interface of tendon-bone was tested at the ends of 3, 6 and 12 weeks after operations, respectively. The cage-squeezing screw can accelerate bone tunel healing and strengthen the graft intension. The experiments proved that the cage-squeezing screw could help the restructuring process of the graft after the beginning of reconstruction. PMID:21774210

  6. Use of self-tapping metal screws for temporary fixation of a resorbable plate system in maxillofacial surgery.

    PubMed

    Iwai, Toshinori; Omura, Susumu; Aoki, Noriaki; Tohnai, Iwai

    2015-05-01

    Resorbable plate systems have been used in maxillofacial surgery to obviate the need for plate removal. However, resorbable plates and screws are very costly, and refixation with additional screws may be necessary when reduction or repositioning of the bone segment is inaccurate. Here we report the use of self-tapping metal screws for temporary fixation of a resorbable plating system in maxillofacial surgery to avoid the use of additional screws following inaccurate fixation or the reuse of resorbable screws, which may result in loosening. PMID:25974798

  7. Early fracture of a bioabsorbable tibial interference screw after ACL reconstruction with subsequent chondral injury.

    PubMed

    Hall, Michael P; Hergan, David M; Sherman, Orrin H

    2009-03-01

    Graft fixation in anterior cruciate ligament (ACL) reconstruction is commonly performed with bioabsorbable devices. This article presents a case of a broken bioabsorbable tibial interference screw (Gentle Threads; Biomet, Warsaw, Indiana) that presented as an intra-articular loose body 4 months after ACL reconstruction with posterior tibialis tendon allograft. A 19-year-old man presented with symptoms of pain and catching for 1 week but reported no history of trauma. The broken screw tip was identified on magnetic resonance imaging examination, and the remaining screw appeared to be overinserted into the tibia. During arthroscopic removal, a 10-mm screw tip was found in the lateral gutter. The ACL graft was found to be well fixed, but small areas of chondral damage were found in the patellofemoral and medial compartment. The patient's symptoms resolved postoperatively. To our knowledge, this is the earliest report of a broken bioabsorbable interference screw and only the second report of subsequent chondral injury due to intra-articular migration. Although rare, late breakage and intra-articular migration of bioabsorbable interference screws should be considered during the postoperative evaluation of any patient with pain or mechanical symptoms, regardless of trauma. This case also supports the importance of both measurement of tibial tunnel length and inspection of the intercondylar notch following interference screw insertion. Orthopedic surgeons performing ACL reconstruction must be aware of this possible complication and its potential for devastating chondral injury. PMID:19309052

  8. Use of Cortical Bone Screws in Maxillofacial Surgery - A Prospective Study

    PubMed Central

    Satish, Madatanapalli; Rahman, NM Mujeeb; Reddy, V Sridhar; Yuvaraj, A; Muliyar, Sabir; Razak, P Abdul

    2014-01-01

    Background: The aim of this study is to evaluate the various applications of cortical bone screws in oral and maxillofacial surgery. Materials & Methods: The study was conducted in a teaching hospital located in, Bangalore, India, on 20 patients. These patients were categorized into three groups depending on the applications of these screws like, for achieving intermaxillary fixation in Group-1, for treatment of simple, undisplaced fractures by “Tension wire” method in Group-2, and further application of these screws were evaluated in Group-3. Different parameters were used to evaluate the efficacy of these screws. Results: In Group-1(n=12) there was satisfactory occlusion in all the patients with minimal incidence of complications. In Group-2 (n=4) post-operative reduction and fixation was satisfactory and in Group-3 (n=4) the function of these screws was satisfactory when it was used for vestibuloplasty and also as a suspension wiring in treatment of comminuted fracture of zygoma with minimal incidence of complications. Conclusion: Use of cortical bone screws is a valid alternative for achieving intermaxillary fixation, reduction and fixation of simple, undisplaced or minimally displaced fractures through Tension wire method owing to its simplicity, economy and ease of use, and as a fixation method for apically positioned flap in vestibuloplasty procedure. How to cite the article: Satish M, Rahman NM, Reddy VS, Yuvaraj A, Muliyar S, Razak PA. Use of Cortical Bone Screws in Maxillofacial Surgery - A Prospective Study. J Int Oral Health 2014;6(2):62-7. PMID:24876704

  9. Occipital condyle screw placement and occipitocervical instrumentation using three-dimensional image-guided navigation.

    PubMed

    Le, Tien V; Burkett, Clint; Ramos, Edwin; Uribe, Juan S

    2012-05-01

    Occipital condyle (OC) screws are an alternative cephalad fixation point in occipitocervical fusion. Safe placement of occipital, C1 lateral mass, and C2 pars screws have been described previously, but not OC screws. The craniocervical junction is complex, and a thorough understanding of the anatomy is needed. Three-dimensional (3D) image-guided navigation was used in six patients. There were no complications related to image-guided navigation during the placement of 12 OC screws and we found that this navigation can serve as a useful adjunct when placing an OC screw. Technical considerations of placing OC and C1 lateral mass screws are discussed with particular reference to patient positioning and the StealthStation® S7™ image-guided navigational platform (Medtronic, Minneapolis, MN, USA). The reference arc is attached to the head-clamp and faces forward. The optical camera and monitor are positioned at the head of the table for a direct, non-obstructed line-of-sight. To minimize intersegmental movement, the OC should not be drilled until all other screws have been placed. We conclude that 3D image-guided navigation is a useful adjunct that can be safely and effectively used for placement of instrumentation of the upper cervical spine including the OC. PMID:22356730

  10. Placement of C2 laminar screws using three-dimensional fluoroscopy-based image guidance

    PubMed Central

    Foy, Andrew B.

    2007-01-01

    The use of C2 laminar screws in posterior cervical fusion is a relatively new technique that provides rigid fixation of the axis with minimal risk to the vertebral artery. The techniques of C2 laminar screw placement described in the literature rely solely on anatomical landmarks to guide screw insertion. The authors report on their experience with placement of C2 laminar screws using three-dimensional (3D) fluoroscopy-based image-guidance in eight patients undergoing posterior cervical fusion. Overall, fifteen C2 laminar screws were placed. There were no complications in any of the patients. Average follow-up was 10 months (range 3–14 months). Postoperative computed tomographic (CT) scanning was available for seven patients allowing evaluation of placement of thirteen C2 laminar screws, all of which were in good position with no spinal canal violation. The intraoperative planning function of the image-guided system allowed for 4-mm diameter screws to be placed in all cases. Using modified Odom’s criteria, excellent or good relief of preoperative symptoms was noted in all patients at final follow-up. PMID:18034268

  11. Fracture risk and initial fixation of a cementless glenoid implant: the effect of numbers and types of screws.

    PubMed

    Suarez, Daniel R; Valstar, Edward R; Rozing, Piet M; van Keulen, Fred

    2013-10-01

    The initial fixation of an anatomical cementless glenoid component, provided by different numbers and types of screws, and the risk of bone fracture were evaluated by estimating the bone-implant interface micromotions and the principal strains around the prosthesis. Four different fixation configurations using locking or compression screws were tested. Estimation of the micromotions at the bone-implant interface was performed both experimentally, using an in vitro model, and computationally, using a numerical model. Principal bone strains were estimated using the numerical model. Subject variability was included by modelling two different bone qualities (healthy and rheumatoid bone). For the fixation configurations that used two screws, experimental and modelling results found that the micromotions at the bone-implant interface did not change with screw type. However, screw type had a significant effect on fixation when only one screw was used; in this case, a locking screw resulted in less micromotion at the bone-implant interface compared with the compression screw. Bone strains were predicted by the numerical model, and strains were found to be independent of the screw type; however, the predicted strain levels calculated in rheumatoid bone were larger than the strain levels that may cause bone damage for most considered arm positions. Predicted bone strain in healthy bone did not reach this level. While proper initial component fixation that allows biological fixation can be achieved by using additional screws, the risk of bone failure around the screws must be considered, especially in cases of weak bone. PMID:23804951

  12. [The Herbert screw in pseudoarthrosis of the carpal scaphoid].

    PubMed

    Massart, P; Tazi, F; Finet, P; Bèzes, H

    1990-01-01

    For nearly three years, the authors have ensured scaphoid union by fixation with a double thread T.J. Herbert's screw. In these 25 cases a cancellous bone graft was used to fill the defect which would have left shortening of the scaphoid Twenty-two of the 25 cases, obtained rapid union, and 20 had a good or very good clinical result. One doubtful union and two cases of non-union occurred. One of these non-unions required revision. The main advantage of this procedure is to allow early mobilization of the wrist. This early is very appreciated by the patients who were immobilized several months by conservative treatment for their initial fracture. PMID:1703425

  13. Rigid-drift magnetohydrodynamic equilibria for cylindrical screw pinches

    NASA Technical Reports Server (NTRS)

    Turner, L.

    1979-01-01

    The rigid-drift equations of MHD equilibria in cylindrical geometry are solved analytically in terms of an infinite series of hypergeometric functions for the case where the pressure is proportional to the square of number density and the current density is arbitrarily pitched. Solutions are obtained for a pure Z pinch, a pure theta pinch, and a general screw pinch. It is found that the shapes of the pressure and magnetic-field profiles are completely determined by the model once two parameters are specified: the local plasma beta on the axis and a quantity related to the pitch of the current density. A set of profiles that resemble those observed experimentally in reversed-field pinches is presented. The results also indicate that hollow pressure profiles and reversed Bz profiles can occur either simultaneously or independently and that the pressure always falls to zero at a finite value of the radius.

  14. [Mechanical circulatory assist using a miniaturized Archimedes screw].

    PubMed

    von Segesser, L K; Bisang, B; Leskosek, B; Turina, M

    1991-01-01

    An axial flow blood pump (Archimedes screw) for intraarterial left ventricular assist was evaluated in comparison to standard roller pump left heart bypass (LHBP) in 13 bovine experiments (bodyweight 74 +/- 15 kg). Full systemic heparinization (ACT greater than 500 s) was used for LHBP in comparison to limited systemic heparinization (ACT greater than 180 s) for axial. A standard battery of blood samples was taken before and at regular intervals throughout perfusion: (table; see text) Transarterial access and relatively limited blood trauma appear to be the main advantages of the evaluated axial flow blood pump. However, the impossibility to assess the pump flow may be a major problem for the management of the failing left ventricle. PMID:2050534

  15. The helical screw expander evaluation project. [for geothermal wells

    NASA Technical Reports Server (NTRS)

    Mckay, R. A.

    1977-01-01

    A positive-displacement helical-screw expander of the Lysholm type has been adapted for geothermal service and successfully demonstrated in a 50 kW prototype power system. Evaluation of the expander by tests of a new model in a 1 MW power system under wellhead conditions in selected liquid-dominated geothermal fields is proposed. The objectives are to determine the performance characteristics of the expander and power system over a broad range of operating conditions and also to examine the concept of wellhead power plants. Throttling and fractionation of the fluids from the test wells is planned to simulate a wide range of wellhead pressures and steam fractions. Variation in the expander exhaust pressure is also planned. The investigation will include expander efficiency, corrosion, erosion, scale formation and control, and endurance testing. Interaction studies with the wells and an electric grid are also proposed.

  16. Early clinical results with cortically based pedicle screw trajectory for fusion of the degenerative lumbar spine.

    PubMed

    Andrew Glennie, R; Dea, Nicolas; Kwon, Brian K; Street, John T

    2015-06-01

    This study reviews the outcomes and revision rates of degenerative lumbar fusion surgery using cortical trajectory pedicle screws in lieu of traditional pedicle screw instrumentation. Pedicle screw fixation can be a challenge in patients with low bone mineral density. Wide posterior approaches to the lumbar spine exposing lateral to the facet joints and onto transverse processes causes an additional degree of muscular damage and blood loss not present with a simple laminectomy. A cortical bone trajectory pedicle screw has been proposed as an alternative to prevent screw pullout and decrease the morbidity associated with the wide posterior approach to the spine. We present a series of eight consecutive patients using a cortical bone trajectory instead of traditional pedicle screw fixation for degenerative conditions of the lumbar spine. A retrospective review of our institutional registry data identified eight patients who had cortical screws placed with the assistance of O-arm Stealth navigation (Medtronic Sofamor Danek, Memphis, TN, USA) from 2010-2013. We analyzed the need for revision, the maintenance of reduction and the incidence of screw pullout or breakage. Our review demonstrated that two of eight patients were revised at an average of 12months. The reasons for these revisions were pseudarthrosis and caudal adjacent segment failure. All patients who were revised had frank screw loosening. We present early clinical results of a new technique that has been shown to have a better fixation profile in laboratory testing. Our less than favorable early clinical results should be interpreted with caution and highlight important technical issues which should be considered. PMID:25769253

  17. Molar distalization with the assistance of Temporary Anchorage Devices.

    PubMed

    Palencar, Adrian J

    2015-01-01

    This article describes efficient techniques for distalization of maxillary and mandibular molars with the assistance of Temporary Anchorage Devices (TADs). There are numerous occasions where the distalization of molars is required in lieu of the odontectomy of bicuspids. In the past, extra-oral force has been used, (i.e. Cervical or Combination Head Gear, or intra-oral force, i.e. Posterior Sagittal Appliance, Modified Greenfield Appliance, Williams DMJ 20001, CD Distalizer, Magill Sagittal, Pendulum Appliance, etc.). All the intra-oral appliances have a common denominator the orthodontic clinician has to deal with, the undesirable expression of the Third Law of Newton. The utilization of TADs allows us to circumvent this shortcoming, establishing an absolute anchorage, and thus completely negate the expression of the Third Law of Newton. PMID:25881377

  18. Ejecta emplacement: from distal to proximal

    NASA Astrophysics Data System (ADS)

    Artemieva, N.

    2008-09-01

    Introduction Most part of impact ejecta is deposited ballistically at some distance from a crater, defined by ejection velocity V and ejection angle ?: d=v2sin?/g. In case of giant impacts, planetary curvature should be taken into account [1]. Combined with ejecta scaling [2], these relations allow to define ejecta thickness as a function of distance. Ejecta from large craters are deposited at velocity high enough to mobilize substrate material and to thicken ejecta deposits [3]. Ballistic approximation is valid for airless bodies (if impact vaporization is not vast) or for proximal ejecta of large impact craters, where ejecta mass per unit area is substantially greater than the mass of involved vapor/atmosphere (M-ratio). Deposition of distal ejecta, in which ejecta mass is negligible compared to the atmosphere, may be also treated in a simplified manner, i.e. as 1) passive motion of ejected particles within an impact plume and 2) later, as sedimentation of particles in undisturbed atmosphere (equilibrium between gravity and drag). In all intermediate M-ratio values, impact ejecta move like a surge, i.e. dilute suspension current in which particles are carried in turbulent flows under the influence of gravity. Surges are well-known for near-surface explosive tests, described in detail for volcanic explosions (Plinian column collapse, phreato-magmatic eruption, lateral blast), and found in ejecta from the Chicxulub [4] and the Ries [5]. Important aspects of surge transport include its ability to deposit ejecta over a larger area than that typical of continuous ballistic ejecta and to create multiple ejecta layers. Numerical model Two-phase hydrodynamics. Surges should be modeled in the frame of two-phase hydrodynamics, i.e. interaction between solid/molten particles and atmospheric gas/impact vapor should be taken into account. There are two techniques of solving equations for dust particle motion in a gas flow. The first one describes solid/molten particles as a liquid with specific properties, i.e. finite-difference equations are the same as in standard hydrodynamics [6-8]. Another approach is based on solving equations of motion for representative particles [9]. Each of these markers describes the motion of a large number of real particles with similar sizes, velocities, and trajectories. Equation of motion (gravity, viscosity, and drag) is solved for every marker and then exchange of momentum, heat and energy with surrounding vaporair mixture is taken into account. This approach is used in the SOVA code [10] and allows to vary particle sizes within a broad range (from a few m to a few microns). Implicit procedure of velocity update allows a larger time step. The substantial advantage of the model is its three-dimensional geometry, allowing modeling of asymmetric deposits of oblique impact ejecta. Turbulent diffusion is taken into account in a simplified manner [6]. Fragments size-frequency distribution (SFD) may be of crucial importance: while large fragments move ballistically, the smallest ones are passively involved in gas motion. Ejected material is usually transformed into particles under tension. The initial particle velocity is given by the hydrodynamic velocity, but the object's initial position within the cell is randomly defined. The SFD of solid fragments in high velocity impacts has been studied experimentally [2,11], numerically [12,13], and has been derived from the lunar and terrestrial crater observations [14,15]. Various approaches may be used to implement fragment size in a dynamic model: in Grady-Kipp model the average fragment size is defined by strain rate [12]; alternatively, average ejection velocity [16] or maximum shock compression [17] may be used. All methods may be verified through comparison with known data. Volcanic direct blast. Numerical modeling of pyroclastic flows, checked against recent observations and young deposits, may be then a useful instrument for reconstruction of terrestrial craters' ejecta, which are mostly eroded or buried; and for impact ejecta study on other planets

  19. Subtrochanteric femur fracture after removal of screws for femoral neck fracture in a child.

    PubMed

    Song, Kwang Soon; Lee, Si Wook

    2015-01-01

    Displaced femoral neck fractures are rare in children and are associated with a high rate of complications. Subtrochanteric fractures after cannulated screw fixation of femoral neck fractures in adults are well recognized, and there are several reports on the topic. However, there are no reports on complications related to hardware or subtrochanteric fractures after removal of the screws in the treatment of femoral neck fractures in children. Here we report the case of a 10-year-old boy who sustained a subtrochanteric fracture after the screw removal and healing that followed a femoral neck fracture. PMID:25566556

  20. Screw-access marking: a technique to simplify retrieval of cement-retained implant prostheses.

    PubMed

    Schoenbaum, Todd R; Chang, Yi-Yuan; Klokkevold, Perry R

    2013-03-01

    One of the commonly cited disadvantages of cement-retained implant prostheses is their inability to be retrievable. The screw-access marking technique discussed in this article allows for any clinician, at any time, to simply and predictably retrieve the cemented implant prosthesis. By applying a discrete, but easily recognizable, marking on the occlusal surface of the restoration, the entry point into the screw-access chamber can be precisely and safely created. The screw-access marking technique is efficient, effective, and widely applicable. PMID:23931268

  1. Bilateral osteochondrosis of the distal tibial epiphysis: a case report.

    PubMed

    Turati, Marco; Afonso, David; Salazard, Bruno; Maillet Declerck, Marie; Bigoni, Marco; Glard, Yann

    2015-03-01

    Osteochondrosis is a developmental disease characterized by an alteration of endochondral ossification. Genetic causes, repetitive mechanical stresses, vascular abnormalities, hormonal imbalances, and interruption of the blood supply to the epiphyseal cartilage are all described causes of osteochondrosis and the etiology is probably multifactorial. Osteochondrosis can occur in different apophysis and epiphysis in all immature skeletons. Distal tibial epiphysis is rarely involved and most of the time unilaterally. We report on an 11-year-old female with bilateral osteochondrosis on distal tibial epiphysis. Only one other similar case has been described in the literature to date. PMID:25504104

  2. Thick fibrous composite reinforcements behave as special second-gradient materials: three-point bending of 3D interlocks

    NASA Astrophysics Data System (ADS)

    Madeo, Angela; Ferretti, Manuel; dell'Isola, Francesco; Boisse, Philippe

    2015-02-01

    In this paper, we propose to use a second gradient, 3D orthotropic model for the characterization of the mechanical behavior of thick woven composite interlocks. Such second-gradient theory is seen to directly account for the out-of-plane bending rigidity of the yarns at the mesoscopic scale which is, in turn, related to the bending stiffness of the fibers composing the yarns themselves. The yarns' bending rigidity evidently affects the macroscopic bending of the material and this fact is revealed by presenting a three-point bending test on {0°/90° and ±45°} specimens of composite interlocks. These specimens differ one from the other for the different relative direction of the yarns with respect to the edges of the sample itself. Both types of specimens are independently seen to take advantage of a second-gradient modeling for the correct description of their macroscopic bending modes. The results presented in this paper are essential for the setting up of a correct continuum framework suitable for the mechanical characterization of composite interlocks. The few second-gradient parameters introduced by the present model are all seen to be associated with peculiar deformation modes of the mesostructure (bending of the yarns) and are determined by inverse approach. Although the presented results undoubtedly represent an important step toward the complete characterization of the mechanical behavior of fibrous composite reinforcements, more complex hyperelastic second-gradient constitutive laws must be conceived in order to account for the description of all possible mesostructure-induced deformation patterns.

  3. Intermittent internal fixation with a locking plate to preserve epiphyseal growth function during limb-salvage surgery in a child with osteosarcoma of the distal femur: a case report.

    PubMed

    Mei, Jiong; Ni, Ming; Jia, Guang-Yao; Chen, Yan-Xi; Zhu, Xiao-Zhong

    2015-05-01

    Limb shortening is a problem associated with surgery for osteosarcoma of the lower extremity in adolescents, as the tumors frequently occur near the epiphysis. Herein we report the use of a less invasive stabilization system (LISS) and an intermittent fixation method to preserve the growth function of epiphysis in an 11-year-old patient with an osteosarcoma of the distal femur.The 11-year-old male presented with left knee enlargement and pain for 2 weeks, and magnetic resonance imaging (MRI) and biopsy were consistent with osteosarcoma of the left distal femur. After preoperative chemotherapy, en bloc tumor resection was performed with margins based on MRI findings preserving the epiphyseal growth plate, the tumor cavity was filled with inactivated bone and bone cement, and a LISS was used to stabilize the femur. Aggressive postoperative chemotherapy was given. Approximately 105 weeks after surgery radiography showed that the distal end of the plate had moved superior to the epiphysis along with bone growth. Locking screws were placed in the distal part of the LISS plate to stabilize the re-implanted bone, and external fixation was not needed.The patient was able to walk with the crutches 1 week postoperatively, and bear weight on the extremity 6 weeks postoperatively. At 6 years after surgery, the patient's height had increased 52?cm, shortening of the affected limb was only 1?cm, and the circumference of the affected limb was 2?cm smaller than that of the contralateral limb. There was no significant discomfort in the affected limb, and there was no gait abnormality. The patient could jump and run, and could participate in sports including basketball and badminton to the same degree as his peers.In summary, the novel method of bone reconstruction and fixation provided good results in a child with an osteosarcoma of the distal femur. This fixation method preserves the osteogenic function of the epiphysis and restored bone integrity simultaneously, and provides good functional recovery. PMID:25997058

  4. 46 CFR 154.524 - Piping joints: Welded and screwed couplings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS...Equipment Cargo and Process Piping Systems § 154.524 Piping joints: Welded...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, 2012 CFR

    2012-10-01

    ... CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS...Equipment Cargo and Process Piping Systems § 154.524 Piping joints: Welded...d) Screwed couplings are allowed for instrumentation and control piping that meets §...

  6. 46 CFR 154.524 - Piping joints: Welded and screwed couplings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS...Equipment Cargo and Process Piping Systems § 154.524 Piping joints: Welded...d) Screwed couplings are allowed for instrumentation and control piping that meets §...

  7. 46 CFR 154.524 - Piping joints: Welded and screwed couplings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS...Equipment Cargo and Process Piping Systems § 154.524 Piping joints: Welded...d) Screwed couplings are allowed for instrumentation and control piping that meets §...

  8. 46 CFR 154.524 - Piping joints: Welded and screwed couplings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS...Equipment Cargo and Process Piping Systems § 154.524 Piping joints: Welded...d) Screwed couplings are allowed for instrumentation and control piping that meets §...

  9. Implant failure in a proximal femoral fracture treated with dynamic hip screw fixation

    PubMed Central

    Dabis, John; Abdul-Jabar, Hani B.; Dabis, Hosam

    2015-01-01

    Dynamic hip screw fixation is a common orthopaedic procedure and to date, still can cause difficulties to the senior trauma surgeon. We present a case where an extra-capsular fracture of the proximal femur was managed with a dynamic hip screw (DHS) fixation. She proceeded to the operating theatre, where the fracture was stabilized with a 75-mm DHS and short-barrelled plate. The implant position was checked with intraoperative screening and the position accepted. Following attempted mobilization at 11 days post-operatively, the patient developed a recurrence of her preoperative pain. X-ray showed that the implant screw had separated from the barrel. Later scrutiny of the intraoperative screening films revealed that the barrel and screw were not engaged at the time of surgery. Intraoperative screening films should be carefully checked to ensure congruity of implant components. PMID:26136561

  10. the dominant force associated with the mo-tion of such screw dislocations (19). At the

    E-print Network

    Jacobel, Robert W.

    the dominant force associated with the mo- tion of such screw dislocations (19). At the onset of condensed matter. References and Notes 1. J. P. Hirth, J. Lothe, Theory of Dislocations (Wiley, New York, ed

  11. Variational equivalence between Ginzburg-Landau, XY spin systems and screw dislocations energies

    E-print Network

    Alicandro, R; Ponsiglione, M

    2009-01-01

    We introduce and discuss discrete two-dimensional models for XY spin systems and screw dislocations in crystals. We prove that, as the lattice spacing $\\e$ tends to zero, the relevant energies in these models behave like a free energy in the complex Ginzburg-Landau theory of superconductivity, justifying in a rigorous mathematical language the analogies between screw dislocations in crystals and vortices in superconductors. To this purpose, we introduce a notion of asymptotic variational equivalence between families of functionals in the framework of $\\Gamma$-convergence. We then prove that, in several scaling regimes, the complex Ginzburg-Landau, the XY spin system and the screw dislocation energy functionals are variationally equivalent. Exploiting such an equivalence between dislocations and vortices, we can show new results concerning the asymptotic behavior of screw dislocations in the $|\\log\\e|^2$ energetic regime.

  12. Variational equivalence between Ginzburg-Landau, XY spin systems and screw dislocations energies

    E-print Network

    R. Alicandro; M. Cicalese; M. Ponsiglione

    2009-07-31

    We introduce and discuss discrete two-dimensional models for XY spin systems and screw dislocations in crystals. We prove that, as the lattice spacing $\\e$ tends to zero, the relevant energies in these models behave like a free energy in the complex Ginzburg-Landau theory of superconductivity, justifying in a rigorous mathematical language the analogies between screw dislocations in crystals and vortices in superconductors. To this purpose, we introduce a notion of asymptotic variational equivalence between families of functionals in the framework of $\\Gamma$-convergence. We then prove that, in several scaling regimes, the complex Ginzburg-Landau, the XY spin system and the screw dislocation energy functionals are variationally equivalent. Exploiting such an equivalence between dislocations and vortices, we can show new results concerning the asymptotic behavior of screw dislocations in the $|\\log\\e|^2$ energetic regime.

  13. Superconducting transition and electrical current in a crystal containing a screw dislocation

    SciTech Connect

    Dubrovskii, I.M.

    1982-04-01

    Development of a superconducting filament near a screw dislocation, transition into the superconducting state of a crystal containing a screw dislocation, and the superconducting current distribution in a crystal containing such a dislocation are considered using the Ginzburg--Landau and London equations. It is shown that conditions for development of the superconducting filament near the screw dislocation depend significantly on the behavior of the order parameter in the dislocation core. It is noted that appearance of the superconducting filament is not a true phase transition, which in fact takes place in a three-dimensional frame of such filaments. It is shown that passage of a current along the screw dislocation leads to the development of a related turbulent filament, which does not disappear when the transport current is switched off.

  14. Implant failure in a proximal femoral fracture treated with dynamic hip screw fixation.

    PubMed

    Dabis, John; Abdul-Jabar, Hani B; Dabis, Hosam

    2015-01-01

    Dynamic hip screw fixation is a common orthopaedic procedure and to date, still can cause difficulties to the senior trauma surgeon. We present a case where an extra-capsular fracture of the proximal femur was managed with a dynamic hip screw (DHS) fixation. She proceeded to the operating theatre, where the fracture was stabilized with a 75-mm DHS and short-barrelled plate. The implant position was checked with intraoperative screening and the position accepted. Following attempted mobilization at 11 days post-operatively, the patient developed a recurrence of her preoperative pain. X-ray showed that the implant screw had separated from the barrel. Later scrutiny of the intraoperative screening films revealed that the barrel and screw were not engaged at the time of surgery. Intraoperative screening films should be carefully checked to ensure congruity of implant components. PMID:26136561

  15. Modeling of wet gas compression in twin-screw multiphase pump

    E-print Network

    Xu, Jian

    2009-05-15

    Twin-screw multiphase pumps experience a severe decrease in efficiency, even the breakdown of pumping function, when operating under wet gas conditions. Additionally, field operations have revealed significant vibration and thermal issues which can...

  16. Performance Evaluation and CFD Simulation of Multiphase Twin-Screw Pumps 

    E-print Network

    Patil, Abhay

    2013-05-16

    Twin-screw pumps are economical alternatives to the conventional multiphase system and are increasingly used in the oil and gas industry due to their versatility in transferring the multiphase mixture with varying Gas Void Fraction (GVF). Present...

  17. [Current status of implant-abutment--part 1: abutments for cemented versus screw retained restorations].

    PubMed

    Harel, N; Livne, S; Piek, D; Marku-Cohen, S; Ormianer, Z

    2012-01-01

    Fixed implant supported single crowns and fixed dental prostheses (FDPs) have become an accepted treatment option for replacing and restoring missing teeth. Recent systematic reviews summarized excellent 5- and 10-year survival rates for both reconstruction types. In screw-retained restorations, the fastening screw provides a solid joint between the restoration and the implant abutment or between the restoration and the implant itself. With cement-retained prostheses, this restorative screw is eliminated for many reasons: esthetics, occlusal stability, and fabrication of passively fitting restorations. The purpose of this article is to review the variety of implant-abutments available for fabrication of fixed implant-supported restoration and compare between the various abutment forms (screw vs. cement retained). PMID:22991873

  18. Distal biceps reconstruction 13 years post-injury.

    PubMed

    Burrus, M Tyrrell; Chhabra, A Bobby

    2015-04-01

    Distal biceps tendon ruptures are relatively rare injuries most commonly caused by an eccentric contraction of the biceps brachii. The majority of complete ruptures receive early surgical intervention, however, some patients do present in a delayed fashion. There are many surgical options at this time for acute and chronic injuries, and this case report describes an Achilles allograft reconstruction in a male who sustained a complete tear 13 years prior to presentation. At 12-month follow up, he had regained full function of his dominant extremity as evidence by returning to work with no limitations and by a Disabilities of the Arm, Shoulder, and Hand (DASH) score of zero. We are unaware of a successfully surgically reconstructed distal biceps tendon of this chronicity. As the literature on this subject is sparse, this case report gives credence to the idea that certain patients with a chronic distal biceps rupture should be considered for operative reconstruction and not relegated to continued failed conservative treatment. Discussed are the surgical treatment options and controversies for chronic distal biceps ruptures, and we review various outcome studies using different surgical techniques. PMID:25829956

  19. Injectable calcium phosphate in the treatment of distal radial fractures

    Microsoft Academic Search

    P. Kopylov; K. Jonsson; K. G. Thorngren; P. Aspenberg

    1996-01-01

    An injectable material which hardened in situ to form a carbonated hydroxyapatite, Norian SRS (Norian Corp., Cupertino, USA), was used as the only treatment of unstable distal radial fractures in six patients. Except for an external dorsal splint for 2 weeks, no other treatment was used. The material maintained reduction except in one case in which there were technical problems

  20. Proximate and Distal Variables in the Demography of Rendille Pastoralists

    Microsoft Academic Search

    Eric Abella Roth

    1999-01-01

    Following the widespread application and success of Bongaarts' proximate fertility framework in the 1980s, anthropologists and demographers have shown increased interest in the delineation of distal fertility variables, alternatively called higher-order by cultural ecologists or ultimate variables by evolutionary ecologists. This shift in focus raises at least four immediate issues: (1) confusion over the role and effect of culture on