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1

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

PubMed Central

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

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

2012-01-01

2

Fatigue strength of common tibial intramedullary nail distal locking screws  

PubMed Central

Background Premature failure of either the nail and/or locking screws with unstable fracture patterns may lead to angulation, shortening, malunion, and IM nail migration. Up to thirty percent of all unreamed nail locking screws can break after initial weight bearing is allowed at 8–10 weeks if union has not occurred. The primary problem this presents is hardware removal during revision surgery. The purposes of our study was to evaluate the relative fatigue resistance of distal locking screws and bolts from representative manufacturers of tibial IM nail systems, and develop a relative risk assessment of screws and materials used. Evaluations included quantitative and qualitative measures of the relative performance of these screws. Methods Fatigue tests were conducted to simulate a comminuted fracture that was treated by IM nailing assuming that all load was carried by the screws. Each screw type was tested ten times in a single screw configuration. One screw type was tested an additional ten times in a two-screw parallel configuration. Fatigue tests were performed using a servohydraulic materials testing system and custom fixturing that simulated screws placed in the distal region of an appropriately sized tibial IM nail. Fatigue loads were estimated based on a seventy-five kilogram individual at full weight bearing. The test duration was one million cycles (roughly one year), or screw fracture, whichever occurred first. Failure analysis of a representative sample of titanium alloy and stainless steel screws included scanning electron microscopy (SEM) and quantitative metallography. Results The average fatigue life of a single screw with a diameter of 4.0 mm was 1200 cycles, which would correspond roughly to half a day of full weight bearing. Single screws with a diameter of 4.5 mm or larger have approximately a 50 percent probability of withstanding a week of weight bearing, whereas a single 5.0 mm diameter screw has greater than 90 percent probability of withstanding more than a week of weight bearing. If two small diameter screws are used, our tests showed that the probability of withstanding a week of weight bearing increases from zero to about 20 percent, which is similar to having a single 4.5 mm diameter screw providing fixation. Conclusion Our results show that selecting the system that uses the largest distal locking screws would offer the best fatigue resistance for an unstable fracture pattern subjected to full weight bearing. Furthermore, using multiple screws will substantially reduce the risk of premature hardware failure. PMID:19371438

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

2009-01-01

3

Distal tibial fracture post syndesmotic screw removal: an adverse complication  

Microsoft Academic Search

Fractures of the ankle are common injuries. Some ankle fractures have an associated injury to the syndesmosis, necessitating\\u000a fixation with one or more screws. Generally, the overall outcome post ankle fracture is good. However, several complications\\u000a have also been described. The current authors describe a distal tibial fracture following syndesmotic screw removal. A 77-year-old\\u000a woman was admitted with a bimaleollar

Mustafa Citak; Manuel Backhaus; Gert Muhr; Thomas Kälicke

4

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

PubMed Central

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

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

2014-01-01

5

Use of the intraosseous screw for unilateral upper molar distalization and found well balanced occlusion  

Microsoft Academic Search

BACKGROUND: The aim of this study was to present a temporary anchorage device with intraosseous screw for unilateral molar distalization to make a space for the impacted premolar and to found well balanced occlusion in a case. CASE PRESENTATION: A 13-year-old male who have an impacted premolar is presented with skeletal Class I and dental Class 2 relationship. The screw

Ibrahim Erhan Gelgor; Ali Ihya Karaman; Tamer Buyukyilmaz

2006-01-01

6

Fatigue strength of common tibial intramedullary nail distal locking screws  

Microsoft Academic Search

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

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

2009-01-01

7

The Effects of Screw Length on Stability of Simulated Osteoporotic Distal Radius Fractures Fixed with Volar Locking Plates  

PubMed Central

Purpose Volar plating for distal radius fractures has caused extensor tendon ruptures secondary to dorsal screw prominence. This study was designed to determine the biomechanical impact of placing unicortical distal locking screws and pegs in an extra-articular fracture model. Methods Volar-locking distal radius plates were applied to 30 osteoporotic distal radius models. Radii were divided into 5 groups based on distal locking fixation: bicortical locked screws, 3 lengths of unicortical locked screws (abutting the dorsal cortex [full length], 75% length, and 50% length to dorsal cortex), and unicortical locked pegs. Distal radius osteotomy simulated a dorsally comminuted, extra-articular, fracture. Each constructs stiffness was determined under physiologic loads (axial compression, dorsal bending volar bending) before and after 1000 cycles of axial conditioning and prior to axial loading to failure (2mm of displacement) and subsequent catastrophic failure. Results Cyclic conditioning did not alter constructs stiffness. Stiffness to volar bending and dorsal bending forces were similar between groups. Final stiffness(N/mm) under axial load was statistically equivalent for all groups: bicortical screws(230), full-length unicortical screws(227), 75% length unicortical screws(226), 50% length unicortical screws(187), unicortical pegs(226). Force(N) at 2 mm displacement was significantly less for 50% length unicortical screws(311) compared to bicortical screws(460), full-length unicortical screws(464), 75% length unicortical screws(400), and unicortical pegs(356). Force(N) to catastrophic fracture was statistically equivalent between groups but mean values for pegs(749) and 50% length unicortical(702) screws were 16-21% less than means for bicortical(892), full-length unicortical(860), and 75% length(894) unicortical constructs. Discussion Locked unicortical distal screws of at least 75% length produce construct stiffness similar to bicortical fixation. Unicortical distal fixation for extra-articular distal radius fractures should be entertained to avoid extensor tendon injury since it does not appear to compromise initial fixation. Clinical Relevance Biomechanical comparison of distal fixation techniques during volar locked plating for distal radius fracture. PMID:22305729

Wall, Lindley B.; Brodt, Michael D.; Silva, Matthew J.; Boyer, Martin I.; Calfee, Ryan P.

2013-01-01

8

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

PubMed

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

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

2014-09-01

9

Bioabsorbable interference screw fixation of distal biceps ruptures through a single anterior incision: a single-surgeon case series and review of the literature  

Microsoft Academic Search

Introduction  We present a single-surgeon series of 14 acute ruptured distal biceps tendons repaired using a biotenodesis screw through\\u000a a single anterior incision.\\u000a \\u000a \\u000a \\u000a \\u000a Patients  The demographics of this population reveal a typical injury pattern and reflect the preponderance of distal biceps ruptures\\u000a in the middle aged, active male. Goniometric post-operative assessment of flexion, pronation and supination range demonstrates\\u000a excellent clinical function in

Will G. P. Eardley; Saurabh Odak; T. Simon Adesina; Richard P. Jeavons; Jim L. McVie

2010-01-01

10

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

PubMed

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

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

2004-03-01

11

A laboratory investigation to assess the influence of cement augmentation of screw and plate fixation in a simulation of distal femoral fracture of osteoporotic and non-osteoporotic bone.  

PubMed

The augmentation of fixation with bone cement is increasingly being used in the treatment of severe osteoporotic fractures. We investigated the influence of bone quality on the mechanics of augmentation of plate fixation in a distal femoral fracture model (AO 33 A3 type). Eight osteoporotic and eight non-osteoporotic femoral models were randomly assigned to either an augmented or a non-augmented group. Fixation was performed using a locking compression plate. In the augmented group additionally 1 ml of bone cement was injected into the screw hole before insertion of the screw. Biomechanical testing was performed in axial sinusoidal loading. Augmentation significantly reduced the cut-out distance in the osteoporotic models by about 67% (non-augmented mean 0.30 mm (sd 0.08) vs augmented 0.13 mm (sd 0.06); p = 0.017). There was no statistical reduction in this distance following augmentation in the non-osteoporotic models (non-augmented mean 0.15 mm (sd 0.02) vs augmented 0.15 mm (sd 0.07); p = 0.915). In the osteoporotic models, augmentation significantly increased stability (p = 0.017). PMID:24078541

Wähnert, D; Lange, J H; Schulze, M; Gehweiler, D; Kösters, C; Raschke, M J

2013-10-01

12

Split spline screw  

NASA Technical Reports Server (NTRS)

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

Vranish, John M. (inventor)

1993-01-01

13

A mechanically interlocked bundle.  

PubMed

The prototype of an artificial molecular machine consisting of a trisammonium tricationic component interlocked with a tris(crown ether) component to form a molecular bundle with averaged C(3v) symmetry has been designed and synthesized. The system is based on noncovalent interactions, which include 1) N(+)-H...O hydrogen bonds; 2) C-H...O interactions between the CH(2)NH(2) (+)CH(2) protons on three dibenzylammonium-ion-containing arms, which are attached symmetrically to a benzenoid core, and three dibenzo[24]crown-8 macrorings fused onto a triphenylene core; and 3) pi...pi stacking interactions between the aromatic cores. The template-directed synthesis of the mechanically interlocked, triply threaded bundle involves post-assembly covalent modification, that is, the efficient conversion of three azide functions at the ends of the arms of the bound and threaded trication into bulky triazole stoppers, after 1,3-dipolar cycloaddition with di-tert-butylacetylenedicarboxylate to the extremely strong 1:1 adduct that is formed in dichloromethane/acetonitrile (3:2), on account of a cluster effect associated with the paucivalent adduct. Evidence for the averaged C(3v) symmetry of the molecular bundle comes from absorption and luminescence data, as well as from electrochemical experiments, (1)H NMR spectroscopy, and mass spectrometry. The photophysical properties of the mechanically interlocked bundle are very similar to those of the superbundle that precedes the formation of the bundle in the process of supramolecular assistance to covalent synthesis. Although weak non-nucleophilic bases (e.g., nBu(3)N and iPr(2)NEt) fail to deprotonate the bundle, the strong tBuOK does, as indicated by both luminescence and (1)H NMR spectroscopy. While deprotonation undoubtedly loosens up the interlocked structure of the molecular bundle by replacing relatively strong N(+)-H...O hydrogen bonds by much weaker N-H...O ones, the pi...pi stacking interactions ensure that any structural changes are inconsequential, particularly when the temperature of the solution of the neutral molecular bundle in dichloromethane is cooled down to considerably below room temperature. PMID:15079832

Badji?, Jovica D; Balzani, Vincenzo; Credi, Alberto; Lowe, James N; Silvi, Serena; Stoddart, J Fraser

2004-04-19

14

Triply interlocked covalent organic cages  

Microsoft Academic Search

Interlocked molecules comprise two or more separate components that are joined by `mechanical' rather than covalent bonds. In other words, these molecular assemblies cannot be dissociated without the cleavage of one or more chemical bonds. Although recent progress has enabled the preparation of such topologies through coordination or templating interactions, three-dimensional interlocked covalent architectures remain difficult to prepare. Here, we

Tom Hasell; Xiaofeng Wu; James T. A. Jones; John Bacsa; Alexander Steiner; Tamoghna Mitra; Abbie Trewin; Dave J. Adams; Andrew I. Cooper

2010-01-01

15

49 CFR 236.750 - Interlocking, automatic.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Interlocking, automatic. 236.750 Section 236.750 Transportation...MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.750 Interlocking, automatic. An arrangement of signals,...

2010-10-01

16

49 CFR 236.772 - Machine, interlocking.  

Code of Federal Regulations, 2012 CFR

...Transportation 4 2012-10-01 2012-10-01 false Machine, interlocking. 236.772 Section 236.772 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.772 Machine, interlocking. An assemblage of manually operated...

2012-10-01

17

49 CFR 236.772 - Machine, interlocking.  

Code of Federal Regulations, 2013 CFR

...Transportation 4 2013-10-01 2013-10-01 false Machine, interlocking. 236.772 Section 236.772 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.772 Machine, interlocking. An assemblage of manually operated...

2013-10-01

18

49 CFR 236.772 - Machine, interlocking.  

Code of Federal Regulations, 2011 CFR

...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...

2011-10-01

19

Automatic interlocking table generation from railway topology  

Microsoft Academic Search

In this paper, an algorithm for automatic interlocking table generation and its implementation is introduced. The specially developed software generates an interlocking table conforming to Turkish Railway regulations. Pseudo codes of the method and their descriptions are given. The method is demonstrated on a small station area, and sample outputs are presented. Keywords-railway, interlocking, signal, point, a

Ahmet Kuzu; Ozgur Songuler; Arcan Sonat; Serhat Turk; Berkin Birol; Ersin H. Dogruguven

2011-01-01

20

12 CFR 348.4 - Interlocking relationships permitted by statute.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Interlocking relationships permitted by statute. 348.4 Section...INTERLOCKS § 348.4 Interlocking relationships permitted by statute. The prohibitions...depository organization that does not do business within the United States except...

2010-01-01

21

12 CFR 711.4 - Interlocking relationships permitted by statute.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Interlocking relationships permitted by statute. 711.4 Section...INTERLOCKS § 711.4 Interlocking relationships permitted by statute. The prohibitions...depository organization that does not do business within the United States except...

2010-01-01

22

12 CFR 212.4 - Interlocking relationships permitted by statute.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Interlocking relationships permitted by statute. 212.4 Section...INTERLOCKS § 212.4 Interlocking relationships permitted by statute. The prohibitions...depository organization that does not do business within the United States except...

2010-01-01

23

12 CFR 26.4 - Interlocking relationships permitted by statute.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Interlocking relationships permitted by statute. 26.4 Section...INTERLOCKS § 26.4 Interlocking relationships permitted by statute. The prohibitions...depository organization that does not do business within the United States except...

2010-01-01

24

12 CFR 563f.4 - Interlocking relationships permitted by statute.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Interlocking relationships permitted by statute. 563f.4 ...INTERLOCKS § 563f.4 Interlocking relationships permitted by statute. The prohibitions...depository organization that does not do business within the United States except...

2010-01-01

25

Coastal protection using topological interlocking blocks  

NASA Astrophysics Data System (ADS)

The coastal protection systems mainly rely on the self-weight of armour blocks to ensure its stability. We propose a system of interlocking armour blocks, which form plate-shape assemblies. The shape and the position of the blocks are chosen in such a way as to impose kinematic constraints that prevent the blocks from being removed from the assembly. The topological interlocking shapes include simple convex blocks such as platonic solids, the most practical being tetrahedra, cubes and octahedra. Another class of topological interlocking blocks is so-called osteomorphic blocks, which form plate-like assemblies tolerant to random block removal (almost 25% of blocks need to be removed for the assembly to loose integrity). Both classes require peripheral constraint, which can be provided either by the weight of the blocks or post-tensioned internal cables. The interlocking assemblies provide increased stability because lifting one block involves lifting (and bending) the whole assembly. We model the effect of interlocking by introducing an equivalent additional self-weight of the armour blocks. This additional self-weight is proportional to the critical pressure needed to cause bending of the interlocking assembly when it loses stability. Using beam approximation we find an equivalent stability coefficient for interlocking. It is found to be greater than the stability coefficient of a structure with similar blocks without interlocking. In the case when the peripheral constraint is provided by the weight of the blocks and for the slope angle of 45o, the effective stability coefficient for a structure of 100 blocks is 33% higher than the one for a similar structure without interlocking. Further increase in the stability coefficient can be reached by a specially constructed peripheral constraint system, for instance by using post-tension cables.

Pasternak, Elena; Dyskin, Arcady; Pattiaratchi, Charitha; Pelinovsky, Efim

2013-04-01

26

49 CFR 236.751 - Interlocking, manual.  

Code of Federal Regulations, 2012 CFR

...manual. An arrangement of signals and signal appliances operated from an interlocking machine and so interconnected by means of mechanical and/or electric locking that their movements must succeed each other in proper sequence, train...

2012-10-01

27

49 CFR 236.751 - Interlocking, manual.  

Code of Federal Regulations, 2011 CFR

...manual. An arrangement of signals and signal appliances operated from an interlocking machine and so interconnected by means of mechanical and/or electric locking that their movements must succeed each other in proper sequence, train...

2011-10-01

28

49 CFR 236.751 - Interlocking, manual.  

Code of Federal Regulations, 2013 CFR

...manual. An arrangement of signals and signal appliances operated from an interlocking machine and so interconnected by means of mechanical and/or electric locking that their movements must succeed each other in proper sequence, train...

2013-10-01

29

49 CFR 236.751 - Interlocking, manual.  

Code of Federal Regulations, 2010 CFR

...manual. An arrangement of signals and signal appliances operated from an interlocking machine and so interconnected by means of mechanical and/or electric locking that their movements must succeed each other in proper sequence, train...

2010-10-01

30

Interlocking egg-crate type grid assembly  

DOEpatents

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.

Kast, S.J.

1985-03-15

31

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

Code of Federal Regulations, 2013 CFR

...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...

2013-10-01

32

Screw fixation of medial malleolar fractures: a cadaveric biomechanical study challenging the current AO philosophy.  

PubMed

The AO Foundation advocates the use of partially threaded lag screws in the fixation of fractures of the medial malleolus. However, their threads often bypass the radiodense physeal scar of the distal tibia, possibly failing to obtain more secure purchase and better compression of the fracture. We therefore hypothesised that the partially threaded screws commonly used to fix a medial malleolar fracture often provide suboptimal compression as a result of bypassing the physeal scar, and proposed that better compression of the fracture may be achieved with shorter partially threaded screws or fully threaded screws whose threads engage the physeal scar. We analysed compression at the fracture site in human cadaver medial malleoli treated with either 30 mm or 45 mm long partially threaded screws or 45 mm fully threaded screws. The median compression at the fracture site achieved with 30 mm partially threaded screws (0.95 kg/cm(2) (interquartile range (IQR) 0.8 to 1.2) and 45 mm fully threaded screws (1.0 kg/cm(2) (IQR 0.7 to 2.8)) was significantly higher than that achieved with 45 mm partially threaded screws (0.6 kg/cm(2) (IQR 0.2 to 0.9)) (p = 0.04 and p < 0.001, respectively). The fully threaded screws and the 30mm partially threaded screws were seen to engage the physeal scar under an image intensifier in each case. The results support the use of 30 mm partially threaded or 45 mm fully threaded screws that engage the physeal scar rather than longer partially threaded screws that do not. A 45 mm fully threaded screw may in practice offer additional benefit over 30 mm partially threaded screws in increasing the thread count in the denser paraphyseal region. PMID:24293597

Parker, L; Garlick, N; McCarthy, I; Grechenig, S; Grechenig, W; Smitham, P

2013-12-01

33

Cannulated screw with solid core insert: stronger than cannulated screws.  

PubMed

We conducted a study to determine if there is a significant difference in ultimate load, yield strength, and fatigue strength between solid core screws and cannulated screws and if a solid core insert placed inside a cannulated screw would have biomechanical effects similar to those of a solid core screw. Five screw designs were tested: Synthes 4.5-mm solid core and 4.5-mm cannulated and our prototype 4.0-mm solid core, 4.0-mm cannulated, and 4.0-mm cannulated with solid core insert. Biomechanical testing with 3-point bending was used to determine ultimate load, yield strength, and cycles to failure for 6 screws of each design. Ultimate load, yield strength, and cycles to failure were significantly (P < .05) lower in the Synthes 4.5-mm cannulated screws than in the Synthes solid core screws and significantly lower in the prototype cannulated screws than in the prototype solid core screws (P < .05) and prototype cannulated screws with solid core inserts (P < .05). There was no significant difference (P > .05) in ultimate load, yield strength, or cycles to failure between the prototype cannulated screws with solid core inserts and the prototype solid core screws. PMID:25251531

Dundon, John M; Gould, Gregory C; Herbenick, Michael A; Hamilton, J Adam

2014-09-01

34

Helical screw viscometer  

DOEpatents

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.

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

1983-06-30

35

Blocks and Screws  

NSDL National Science Digital Library

In this lesson, each student is given a block of wood and a screw (or nail), and is asked to put the screw into the block, without any tool (like a screwdriver or hammer). Their efforts, with varying success, lead to a discussion of contrivances, using various items and strategies as make-do (contrived) tools for which they were not intended, and an exploration of many examples of contrivances or adaptive compromises and other imperfections in the living world, especially in humans. This situation may be better explained by evolution rather than the result of intelligent design.

Patterson, Tim

36

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

37

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

38

Interlocking mechanical and fluidic interconnections for microfluidic circuit boards  

Microsoft Academic Search

Deep reactive ion etching (DRIE) is employed to fabricate mechanically interlocking structures through which high-density fluidic interconnections are provided between microchannel-containing substrates. The geometric versatility that is achievable with DRIE facilitates the fabrication of high density interconnects of two types: (1) structures with mechanically interlocking “fins” used to align arbitrarily placed fluidic via holes and (2) interlocking hole and notched

B. L. Gray; S. D. Collins; R. L. Smith

2004-01-01

39

Low noise lead screw positioner  

NASA Technical Reports Server (NTRS)

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.

Perkins, Gerald S. (inventor)

1986-01-01

40

Helical screw expander evaluation project  

Microsoft Academic Search

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

R. McKay

1982-01-01

41

21 CFR 876.4590 - Interlocking urethral sound.  

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

42

21 CFR 876.4590 - Interlocking urethral sound.  

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

43

21 CFR 876.4590 - Interlocking urethral sound.  

...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...

2014-04-01

44

21 CFR 876.4590 - Interlocking urethral sound.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

45

21 CFR 876.4590 - Interlocking urethral sound.  

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

46

Surgical treatment of distal biceps rupture.  

PubMed

Rupture of the distal biceps tendon accounts for 10% of all biceps brachii ruptures. Injuries typically occur in the dominant elbow of men aged 40 to 49 years during eccentric contraction of the biceps. Degenerative changes, decreased vascularity, and tendon impingement may precede rupture. Although nonsurgical management is an option, healthy, active persons with distal biceps tendon ruptures benefit from early surgical repair, gaining improved strength in forearm supination and, to a lesser degree, elbow flexion. Biomechanical studies have tested the strength and displacement of various repairs; the suspensory cortical button technique exhibits maximum peak load to failure in vitro, and suture anchor and interosseous screw techniques yield the least displacement. Surgical complications include sensory and motor neurapraxia, infection, and heterotopic ossification. Current trends in postoperative rehabilitation include an early return to motion and to activities of daily living. PMID:20190104

Sutton, Karen M; Dodds, Seth D; Ahmad, Christopher S; Sethi, Paul M

2010-03-01

47

Carbon nanotube Archimedes screws.  

PubMed

Recently, nanomechanical devices composed of a long stationary inner carbon nanotube and a shorter, slowly rotating outer tube have been fabricated. In this paper, we study the possibility of using such devices as nanoscale transducers of motion into electricity. When the outer tube is chiral, we show that such devices act like quantum Archimedes screws, which utilize mechanical energy to pump electrons between reservoirs. We calculate the pumped charge from one end of the inner tube to the other, driven by the rotation of a chiral outer nanotube. We show that the pumped charge can be greater than one electron per 360° rotation, and consequently, such a device operating with a rotational frequency of 10 MHz, for example, would deliver a current of ?1 pAmp. PMID:21126086

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

2010-12-28

48

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

Code of Federal Regulations, 2013 CFR

...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...

2013-10-01

49

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

Code of Federal Regulations, 2012 CFR

...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...

2012-10-01

50

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

Code of Federal Regulations, 2010 CFR

...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...

2010-10-01

51

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

Code of Federal Regulations, 2011 CFR

...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...

2011-10-01

52

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

Code of Federal Regulations, 2011 CFR

...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...

2011-10-01

53

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

Code of Federal Regulations, 2012 CFR

...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...

2012-10-01

54

18 CFR 45.9 - Automatic authorization of certain interlocking positions.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Automatic authorization of certain interlocking...HOLD INTERLOCKING POSITIONS § 45.9 Automatic authorization of certain interlocking...this condition, and will constitute automatic denial. (c) Informational...

2010-04-01

55

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

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312...Interlocking Standards § 236.312 Movable bridge, interlocking of signal appliances with...

2011-10-01

56

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

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312...Interlocking Standards § 236.312 Movable bridge, interlocking of signal appliances with...

2013-10-01

57

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312...Interlocking Standards § 236.312 Movable bridge, interlocking of signal appliances with...

2010-10-01

58

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

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312...Interlocking Standards § 236.312 Movable bridge, interlocking of signal appliances with...

2012-10-01

59

Biodegradable interlocking nails for fracture fixation.  

PubMed

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

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

1998-12-01

60

The Ignition Interlock Program for Drunk Drivers: A Multivariate Test  

Microsoft Academic Search

The ignition interlock has been touted as a “high-tech” intervention to reduce drunk-driving recidivism. However, it has been difficult to evaluate because outcomes may be a result of program selection. In the study reported here, a random sample of interlock cases was contrasted against a comparison group of impaired drivers in a retrospective analysis. Program effects were tested through a

Michael Weinrath

1997-01-01

61

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

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

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

62

12 CFR 250.407 - Interlocking relationship involving securities affiliate of brokerage firm.  

Code of Federal Regulations, 2010 CFR

... false Interlocking relationship involving securities...407 Interlocking relationship involving securities...Corporation”) engaged in business of the kinds described...section 32 (“section 32 business”). (b)...

2010-01-01

63

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

Code of Federal Regulations, 2010 CFR

...false Interlocking relationships between member bank...variable annuity insurance company. 250.411 Section...411 Interlocking relationships between member bank...variable annuity insurance company. (a) The...

2010-01-01

64

Design for assembly : a computational approach to construct interlocking wooden frames  

E-print Network

This thesis explores the computational process of generating and constructing interlocking frames. Its outcome delivers a sophisticated software tool that creates a three dimensional interlocking pattern, analyzes the ...

Tai, Alan Song-Ching

2012-01-01

65

Power connect safety and connection interlock  

NASA Technical Reports Server (NTRS)

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.

Rippel, Wally E. (Inventor)

1992-01-01

66

Distal radius triplane fracture.  

PubMed

A triplane fracture is so named because of the three planes traversed by the fracture line. These are physeal fractures that result from injury during the final phase of maturation and cessation of growth. This fracture pattern typically involves the distal tibia. We present a rare case of a triplane fracture involving the distal radius. PMID:25350166

Parkar, Aah; Marya, S; Auplish, S

2014-11-01

67

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

Microsoft Academic Search

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

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

2004-01-01

68

Refining the maintenance techniques for Interlocking Concrete Paver GIs - abstract  

EPA Science Inventory

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

69

Refining the maintenance techniques for Interlocking Concrete Paver GIs  

EPA Science Inventory

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

70

An Articulating Tool for Endoscopic Screw Delivery  

E-print Network

This paper describes the development of an articulating endoscopic screw driver that can be used to place screws in osteosynthetic plates during thoracoscopic surgery. The device is small enough to be used with a 12 mm ...

Petrzelka, Joseph Edward

71

Giant distal humeral geode.  

PubMed

We describe the imaging features of a giant geode of the distal humerus in a patient with rheumatoid arthritis, which presented initially as a pathological fracture. The value of magnetic resonance imaging in establishing this diagnosis is emphasized. PMID:10794554

Maher, M M; Kennedy, J; Hynes, D; Murray, J G; O'Connell, D

2000-03-01

72

Biomechanical comparison of inside–outside screws, cables, and regular screws, using a sawbone model  

Microsoft Academic Search

Our aim was to conduct a biomechanical comparison of the pull-out strengths of inside–outside (I\\/O) screws, cables, and bone screws to determine whether I\\/O screws provide greater pull-out resistance than cables or bone screws, and their effectiveness with the screw diameter. There is no remarkable biomechanical experimental study comparing the I\\/O technique with conventional spinal techniques. The diameter of the

Yusuf Sukru Caglar; Fuat Torun; Thomas Glenn Pait; William Hogue; Melih Bozkurt; Serdar Özgen

2005-01-01

73

Comparison of Pullout Strength between 3.5-mm Fully Threaded, Bicortical Screws and 4.0-mm Partially Threaded, Cancellous Screws in the Fixation of Medial Malleolar Fractures  

Microsoft Academic Search

Displaced medial malleolus fractures are considered unstable and typically require open reduction and internal fixation for anatomic reduction and early joint range of motion. These fractures are usually fixated with either compression lag screws or tension band wiring depending on the fracture pattern, size of the distal fragment, and bone quality. When fracture fixation fails, it is typically in pullout

Jason D. Pollard; Ali Deyhim; Ryan B. Rigby; Nathan Dau; Christy King; Lawrence M. Fallat; Cynthia Bir

2010-01-01

74

Helical screw expander evaluation project  

NASA Technical Reports Server (NTRS)

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.

Mckay, R.

1982-01-01

75

Helical screw expander evaluation project  

NASA Astrophysics Data System (ADS)

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.

McKay, R.

1982-03-01

76

Fiduciary duties of interlocking directors within a nonprofit health system.  

PubMed

In response to regulatory and financial pressures, entities participating in the healthcare industry have joined with others in order to maintain, even improve, their market positions. In the non-profit sector of the industry, partnerships, mergers, and acquisitions have included arrangements whereby some corporate partners have interlocking directors. After review of the fiduciary duties of care and loyalty owed by corporate board members, and their application to traditional performance and conflict of interest situations, the authors address two scenarios raising interlocking director issues. PMID:16477798

Hershey, Nathan; Jarzab, Christine M

2005-01-01

77

75 FR 61820 - Model Specifications for Breath Alcohol Ignition Interlock Devices (BAIIDs)  

Federal Register 2010, 2011, 2012, 2013

...NHTSA-2010-0033] Model Specifications for Breath Alcohol Ignition Interlock Devices (BAIIDs...to the Model Specifications for Breath Alcohol Ignition Interlock Devices (BAIIDs...motor vehicle when the driver's breath alcohol concentration (BrAC) is at or...

2010-10-06

78

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

Federal Register 2010, 2011, 2012, 2013

...NHTSA-2013-0058] Model Specifications for Breath Alcohol Ignition Interlock Devices (BAIIDs...revises the Model Specifications for Breath Alcohol Ignition Interlock Devices (BAIIDs...motor vehicle when the driver's breath alcohol concentration (BrAC) is at or...

2013-05-08

79

Endoscopic ACL reconstruction using stryker biosteon cross-pin femoral fixation and interlock cross-pin tibial fixation.  

PubMed

Hamstring tendon autografts have, over the past decade, increasingly become the graft of choice for anterior cruciate ligament (ACL) reconstructions. Studies have shown that multiply stranded hamstring grafts have superior biomechanical characteristics when compared to patellar tendon autografts. Harvests of hamstring tendons have been shown to cause less donor-site morbidity than the harvest of patellar bone-tendon-bone grafts. Historically, however, fixation methods for hamstring grafts have limited their successful use. Fixation for both the tibia and femur distant from the intra-articular portions of the graft decreased the stiffness of the construct. The fixation also contributed to tunnel widening and ganglion formation. New methods have been developed to maximize the mechanical strengths of hamstring grafts and optimize biological factors in healing of the graft to the bone tunnels. Femoral cross-pin fixation provides secure fixation close to the knee joint, while also allowing for placement of the graft in the native ACL footprint at the far posterior aspect of the intercondylar notch. Tibial interference screw fixation allows fixation close to the joint as well. Addition of the interlock pin through the interference screw increases pullout strength significantly. Recent advances in material science have led to the development of bioabsorbable implants that afford high initial fixation strengths while limiting subsequent complications from permanent hardware. PMID:15455332

Berg, Troy L; Paulos, Lonnie E

2004-01-01

80

Optimal technique of screw placement in the ischial tuberosity for posterior acetabular fractures.  

PubMed

Thirty dry adult bony specimens and eight embalmed cadavers were used to report on the morphological data of the ischial tuberosity and to determine the most optimal technique for ischial tuberosity screw placement for open reduction and internal fixation of posterior acetabular fractures. The average width, height, and depth of the ischial tuberosity were 27.0 mm, 32.2 mm, and 32.4 mm, respectively. The average angles between the posterior and medial aspects and between the posterior and lateral aspects of the ischial tuberosities were 79.5 degrees, and 111.5 degrees, respectively. The risk to the internal pudendal neurovascular bundle increases with either a more medially placed screw or a laterally placed screw that is angled medially. The tendinous origin of the hamstrings becomes quite substantial (7-10 mm thick) at a point 2 cm distal to the inferior acetabular margin. The exposure of the ischial tuberosity should therefore be restricted to this level. The entry point of the screws should be 5 mm or 10 mm medial to the lateral margin of the ischial tuberosity, and the screws should be directed 35-40 degrees, 45-50 degrees, and 50-55 degrees caudally at the level of the inferior acetabular margin and 1 cm and 2 cm below it, respectively, to obtain the most favorable bony purchase. PMID:8667107

Xu, R; Ebraheim, N A; Biyani, A; Yeasting, R A

1996-01-01

81

Design of a robotic tool for percutaneous instrument distal tip repositioning.  

PubMed

Manually performed image-guided percutaneous procedures are limited by targeting errors due to instrument misalignment, deflection and an inability to reposition the distal tip of the instrument after it has been percutaneously inserted. These limitations result in suboptimal instrument positioning that limits diagnosis and treatment for a variety of procedures as well as excessive procedure time and radiation dose (in the case of x-ray based imaging). Hence we are developing a robotic tool capable of repositioning the distal tip of a percutaneous instrument after a single insertion into the body. It is based on the concept of deploying a super-elastic pre-curved stylet from a concentric straight cannula. The proximal end of the cannula is attached to the distal end of a screw-spline that enables it to be translated and rotated with respect to the casing. Translation of the stylet relative to the cannula is achieved with a second threaded screw with a splined groove. The device is made of mostly plastic components and actuation is achieved using micro-stepper motors. Measurements of the maximum axial force for the cannula screw-spline and stylet screw were found to match those from design calculations. Evaluation of the mechanism positioning capability demonstrated sub-millimeter and sub-degree translation and angular accuracy. We foresee this robotic tool having wide application across a range of procedures such as biopsy, thermal ablation and brachytherapy seed placement. PMID:22254751

Walsh, Conor James; Franklin, Jeremy; Slocum, Alexander H; Gupta, Rajiv

2011-01-01

82

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

Microsoft Academic Search

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

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

2002-01-01

83

Description of a system for interlocking elevated temperature mechanical tests  

NASA Astrophysics Data System (ADS)

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.

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

1995-07-01

84

Simulation and Verification of UML-based Railway Interlocking Designs  

E-print Network

. Keywords: Railway Interlocking System, UML, Simulation, Verification, Model Checking, Multi-Object Checking by simulation and animation, the other is verification by model checking. The first method is supported to cover all the possible situations by test cases for verification and validation. Verification by model

Paris-Sud XI, Université de

85

Computerized Interlocking System for Railway Signaling Control: SMILE  

Microsoft Academic Search

A computerized interlocking system for railway signaling control is proposed. The overall architecture of this system, aiming at a high degree of safety, reliability, and flexibility, is shown. The basic architecture of both a fail-safe microcomputer subsystem which is the kernel of this system and system-bus structured multimicrocomputer subsystem is discussed. Based on the results of the quantitative evaluation, system

Katsuji Akita; Toshikatsu Watanabe; Hideo Nakamura; Ikumasa Okumura

1985-01-01

86

TTCN-3 Testing of Hoorn-Kersenboogerd Railway Interlocking  

Microsoft Academic Search

Railway control systems are safety-critical, so we have to ensure that they are designed and implemented correctly. Testing these systems is a key issue. Prior to system testing, the software of a railway control system is tested separately from the hardware. The interlocking is a layer of railway control systems that guarantees safety. It allows to execute commands given by

Jens R. Calame; Nicolae Goga; Natalia Ioustinova; Jaco Van De Pol

2006-01-01

87

How Does Learning Intent Affect Interlocking Directorates Dynamic?  

ERIC Educational Resources Information Center

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

Simoni, Michele; Caiazza, Rosa

2012-01-01

88

Application of programmable controllers to vacuum system interlocks  

Microsoft Academic Search

A programmable control system (PCS) is presented which performs all interlock logic operations required by the Doublet III vacuum control system. The PCS can be programmed to perform complex logic operations on any number of inputs within the limits of the memory capacity. Up\\/down counters and delay functions can also be programmed. The programmable control system contains a 1024 word

G. Lee; D. Moore

1979-01-01

89

Wet Granulation in a Twin-Screw Extruder: Implications of Screw Design  

E-print Network

as an efficient and flexible technique for continuous high-shear wet granulation. Extruders can readily processWet Granulation in a Twin-Screw Extruder: Implications of Screw Design M.R. THOMPSON, J. SUN MMRI granulation in twin-screw extrusion machinery is an attractive tech- nology for the continuous processing

Thompson, Michael

90

Distal radioulnar joint injuries  

PubMed Central

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

Thomas, Binu P; Sreekanth, Raveendran

2012-01-01

91

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

PubMed

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

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

2014-09-01

92

Biomechanical comparison of pedicle screws versus spinous process screws in C2 vertebra  

PubMed Central

Background: Biomechanical studies have shown C2 pedicle screw to be the most robust in insertional torque and pullout strength. However, C2 pedicle screw placement is still technically challenging. Smaller C2 pedicles or medial localization of the vertebral artery may preclude safe C2 pedicle screw placement in some patients. The purpose of this study was to compare the pullout strength of spinous process screws with pedicle screws in the C2. Materials and Methods: Eight fresh human cadaveric cervical spine specimens (C2) were harvested and subsequently frozen to ?20°C. After being thawed to room temperature, each specimen was debrided of remaining soft tissue and labeled. A customs jig as used to clamp each specimen for screw insertion firmly. Screws were inserted into the vertebral body pairs on each side using one of two methods. The pedicle screws were inserted in usual manner as in previous biomechanical studies. The starting point for spinous process screw insertion was located at the junction of the lamina and the spinous process and the direction of the screw was about 0° caudally in the sagittal plane and about 0° medially in the axial plane. Each vertebrae was held in a customs jig, which was attached to material testing machine (Material Testing System Inc., Changchun, China). A coupling device that fit around the head of the screw was used to pull out each screw at a loading rate of 2 mm/min. The uniaxial load to failure was recorded in Newton'st dependent test (for paired samples) was used to test for significance. Results: The mean load to failure was 387 N for the special protection scheme and 465 N for the protection scheme without significant difference (t = ?0.862, P = 0.403). In all but three instances (38%), the spinous process pullout values exceeded the values for the pedicle screws. The working distances for the spinous process screws was little shorter than pedicle screws in each C2 specimen. Conclusion: Spinous process screws provide comparable pullout strength to pedicle screws of the C2. Spinous process screws may provide an alternative to pedicle screws fixation, especially with unusual anatomy or stripped screws.

Liu, Guan-yi; Mao, Lu; Xu, Rong-ming; Ma, Wei-hu

2014-01-01

93

Helical rotary screw expander power system  

Microsoft Academic Search

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

R. A. McKay; R. S. Sprankle

1974-01-01

94

Distal radius fixation through a mini-invasive approach of 15 mm. PART 1: a series of 144 cases.  

PubMed

The volar Henry approach is becoming the gold standard for distal radius fracture fixation. It decreases the incidence of nonunion, limits complications especially complex regional pain syndrome (CRPS) type I, and allows early mobilization of the wrist. Nonetheless, it has some disadvantages such as the size of the incision, which is not esthetically pleasing, and the loss of ligamentotaxis. This is why some authors have developed a mini-invasive approach. The aim of this work was to evaluate the feasibility of the anterior mini-invasive approach of 15 mm in a clinical series of 144 cases of distal radius fracture. All patients were operated under regional anesthesia using the same techniques by five surgeons of the same team. According to the AO classification, there were 83 type A fractures, 2 type B, and 59 type C. A volar plate (Step One(®), Newclip Technics™, Haute-Goulaine, France) was used in all cases. The 2 proximal metaphyseal screws and the 2 distal central epiphyseal screws were monoaxial locking. The 2 distal ulnar and radial epiphyseal screws were placed in polyaxial locking at 20° angulation maximum. Skin closure without drainage was performed. No postoperative immobilization was prescribed, and patients were encouraged to use their upper limb immediately postoperative. No postoperative physiotherapy was prescribed. The mean follow-up was 4.1 months. The final size of the incision was on average 16.1 mm. Mean pain score was 1.8. The Quick DASH score was average 25. Average range of motion was more than 85 %, and global force of the hand was 67 % compared with contralateral side. On X-ray, the mean radial slope was 22°, the mean radial tilt was 8.3°, and the mean radioulnar variance/index was -0.4 mm. There were nine cases of CRPS type I, which all resolved. Specific complications included two secondary displacements and nine tenosynovitis cases. No tendon rupture was noted. Two intra-articular distal radioulnar joint screws had to be removed at 3 months. One epiphyseal screw required removal 1 month postoperative due to loosening. There were no intra-articular radiocarpal screws. Distal radius fracture fixation using a mini-invasive approach is a reliable and reproducible procedure with few complications. It allows anatomical reduction in the distal radius fractures including intra-articular ones. It can be associated with arthroscopy, scaphoid screw fixation or even percutaneous pinning. Thus, most traumatic lesions of the wrist bony or soft tissue can be treated through this mini-invasive approach. PMID:24258689

Lebailly, Frédéric; Zemirline, Ahmed; Facca, Sybille; Gouzou, Stéphanie; Liverneaux, Philippe

2014-08-01

95

Engineering interlocking DNA rings with weak physical interactions.  

PubMed

Catenanes are intriguing molecular assemblies for engineering unique molecular devices. The resident rings of a catenane are expected to execute unhindered rotation around each other, and to do so, they must have weak physical interactions with each other. Due to sequence programmability, DNA has become a popular material for nanoscale object engineering. However, current DNA catenanes, particularly in the single-stranded (ss) form, are synthesized through the formation of a linking duplex, which makes them less ideal as mobile elements for molecular machines. Herein we adopt a random library approach to engineer ssDNA [2] catenanes (two interlocked DNA rings) without a linking duplex. Results from DNA hybridization, double-stranded catenane synthesis and rolling circle amplification experiments signify that representative catenanes have weak physical interactions and are capable of operating as independent units. Our findings lay the foundation for exploring free-functioning interlocked DNA rings for the design of elaborate nanoscale machines based on DNA. PMID:24969435

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

2014-01-01

96

Engineering interlocking DNA rings with weak physical interactions  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

97

Availability Analysis of the Ventilation Stack CAM Interlock System  

SciTech Connect

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

YOUNG, J.

2000-08-09

98

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

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

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

99

Formal Verification of a Railway Interlocking System using Model Checking  

Microsoft Academic Search

.   In this paper we describe an industrial application of formal methods. We have used model checking techniques to model and\\u000a formally verify a rather complex software, i.e. part of the “safety logic” of a railway interlocking system. The formal model\\u000a is structured to retain the reusability and scalability properties of the system being modelled. Part of it is defined

Alessandro Cimatti; Fausto Giunchiglia; Giorgio Mongardi; Dario Romano; Fernando Torielli; Paolo Traverso

1998-01-01

100

Macro-micro Interlocked Simulation for Multiscale Phenomena  

Microsoft Academic Search

A new methodology for the simulation of multiscale pro-cesses, called Macro-Micro Interlocked (MMI) Simulation, is introduced.\\u000a The MMI simulation is carried out by the two-way connection of different numerical models, which may handle macroscopic and\\u000a microscopic dynamics, respectively. The MMI simulation are applied to several multiscale phenomena, for instance, cloud formation,\\u000a gas detonation, and plasma dynamics. The results indicate that

Kanya Kusano; Shigenobu Hirose; Toru Sugiyama; Shinichiro Shima; Akio Kawano; Hiroki Hasegawa

2007-01-01

101

A simple electron cone interlock system for the clinac-18.  

PubMed

A simple electron cone-collimator interlock system has been developed for the Clinac-18. Each cone is assigned a special slot in the storage cabinet and, upon being taken for treatment setup, sends out a binary coded decimal (BCD) signal to the control console. The voltage from the collimator setting must match the BCD signal or a comparator logic will drive the fault matrix to prevent the accelerator from energizing. PMID:7360974

Chan, Y K; Walulik, B

1980-04-01

102

Flammable gas interlock spoolpiece flow response test report  

SciTech Connect

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

Schneider, T.C., Fluor Daniel Hanford

1997-03-24

103

The biomechanics of guided growth: does screw size, plate size, or screw configuration matter?  

PubMed

Guided growth with the eight-plate is a commonly used technique to correct angular limb deformities in children. However, the optimal combination of plate size, screw size, and screw configuration has not been determined. Using osteotomized femoral sawbones and a rail frame, we developed a growth model to examine the effect of these variables at 6-month, 12-month, and 18-month growth increments. The mean annual coronal plane change was 11.3°. Screw size and plate size were not associated with the rate of angular correction. Screw configuration was important, with parallel screws resulting in optimal correction at all time points compared with divergent screws (P<0.05). PMID:24322536

Schoenleber, Scott J; Iobst, Christopher A; Baitner, Avi; Standard, Shawn C

2014-03-01

104

Semi-Empirical Screw Compressor Chiller Model  

E-print Network

A screw chiller model which is based on a first principles, semi-empirical analysis that describes the system performance based on observations of the thermodynamic processes is developed. This model is a modified method to empirically derive...

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

105

Additional Drive Circuitry for Piezoelectric Screw Motors  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

106

New beam-charge interlock system for radiation safety at the KEKB injector linac  

Microsoft Academic Search

A new beam-charge interlock system is under development for radiation safety and machine protection at the KEKB injector linac. A hardware-based interlock system is required instead of the present software-based interlock system in order to boost its reliability. This system restricts the integrated amount of beam charges delivered to four different storage rings. The beam charges are measured using wall-current

T. Suwada; E. Kadokura; M. Satoh; K. Furukawa

2008-01-01

107

Intramedullary screw fixation of lateral malleolus fractures.  

PubMed

A biomechanical evaluation of intramedullary versus buttress plate and lag screw fixation of lateral malleolus fractures is combined with a clinical evaluation of 44 patients with lateral malleolus fractures who underwent intramedullary screw fixation. The biomechanical study was performed in experimentally produced, Weber B, supination-eversion ankle fractures. The fractures were fixed with one of the two above fixation methods and then placed under a torsional load to failure. Sixteen cadaver ankles were tested as compared with native bone. The intramedullary screw provided 66.5% the resistance of torsion, and the buttress plate and lag screw provided 61.5% the resistance to torsion. There was no statistical difference between these two groups. The 44 fractures treated with an intramedullary screw were reviewed retrospectively. There was one failure of fixation, and one prominent hardware problem. Time to full weightbearing averaged 7.2 weeks. These results suggest that intramedullary screw fixation of noncomminuted lateral malleolus fractures provides stable fixation with good clinical results. This technique has the advantages of providing dynamic intramedullary fixation with limited surgical dissection and no subcutaneous hardware. PMID:7849975

Bankston, A B; Anderson, L D; Nimityongskul, P

1994-11-01

108

Distal symphalangism associated with camptodactyly  

Microsoft Academic Search

A Japanese family in which four patients in three generations had distal symphalangism associated with camptodactyly is reported. All of these patients had extension limitation of the proximal interphalangeal joints of the toes of both feet. Radiographs of the hands and feet, undertaken in three cases, showed no bone fusion of the distal and proximal interphalangeal joints. This malformation is

S Ohdo; Y Yamauchi; K Hayakawa

1981-01-01

109

National Synchrotron Light Source medical personnel protection interlock  

SciTech Connect

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.

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

1998-11-01

110

Distal plate placement for distal radius fractures limits wrist motion  

Microsoft Academic Search

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,

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

111

Effect of Screw Length on Bioabsorbable Interference Screw Fixation in a Tibial Bone Tunnel  

Microsoft Academic Search

Initial tibial fixation strength is the weak link after anterior cruciate ligament reconstruction with a quadrupled hamstring tendon graft fixed with bioabsorbable interference screws. The purpose of this study was to determine the biomechanical differences between 28-mm and tapered 35-mm interference screws for tibial fixation of a soft tissue graft in 16 young cadaveric tibias. Failure mode, displacement before failure,

Jeffrey B. Selby; Darren L. Johnson; Peter Hester; David N. M. Caborn

2001-01-01

112

The Turn of the Screw: Optimal Design of an Archimedes Screw  

Microsoft Academic Search

The geometry of an Archimedes screw is governed by certain external parameters (its outer radius, length, and slope) and certain internal parameters (its inner radius, number of blades, and the pitch of the blades). The external parameters are usually determined by the location of the screw and how much water is to be lifted. The internal parameters, however, are free

Chris Rorres

2000-01-01

113

Metal artifacts from titanium and steel screws in CT, 1.5T and 3T MR images of the tibial Pilon: a quantitative assessment in 3D  

PubMed Central

Radiographs are commonly used to assess articular reduction of the distal tibia (pilon) fractures postoperatively, but may reveal malreductions inaccurately. While magnetic resonance imaging (MRI) and computed tomography (CT) are potential three-dimensional (3D) alternatives they generate metal-related artifacts. This study aims to quantify the artifact size from orthopaedic screws using CT, 1.5T and 3T MRI data. Three screws were inserted into one intact human cadaver ankle specimen proximal to and along the distal articular surface, then CT, 1.5T and 3T MRI scanned. Four types of screws were investigated: titanium alloy (TA), stainless steel (SS) (Ø =3.5 mm), cannulated TA (CTA) and cannulated SS (CSS) (Ø =4.0 mm, Ø empty core =2.6 mm). 3D artifact models were reconstructed using adaptive thresholding. The artifact size was measured by calculating the perpendicular distance from the central screw axis to the boundary of the artifact in four anatomical directions with respect to the distal tibia. The artifact sizes (in the order of TA, SS, CTA and CSS) from CT were 2.0, 2.6, 1.6 and 2.0 mm; from 1.5T MRI they were 3.7, 10.9, 2.9, and 9 mm; and 3T MRI they were 4.4, 15.3, 3.8, and 11.6 mm respectively. Therefore, CT can be used as long as the screws are at a safe distance of about 2 mm from the articular surface. MRI can be used if the screws are at least 3 mm away from the articular surface except for SS and CSS. Artifacts from steel screws were too large thus obstructed the pilon from being visualised in MRI. Significant differences (P<0.05) were found in the size of artifacts between all imaging modalities, screw types and material types, except 1.5T versus 3T MRI for the SS screws (P=0.063). CTA screws near the joint surface can improve postoperative assessment in CT and MRI. MRI presents a favourable non-ionising alternative when using titanium hardware. Since these factors may influence the quality of postoperative assessment, potential improvements in operative techniques should be considered. PMID:24914417

Radzi, Shairah; Cowin, Gary; Robinson, Mark; Pratap, Jit; Volp, Andrew; Schuetz, Michael A.

2014-01-01

114

Genetics Home Reference: Distal arthrogryposis type 1  

MedlinePLUS

... OMIM Genetic disorder catalog Conditions > Distal arthrogryposis type 1 On this page: Description Genetic changes Inheritance Diagnosis ... Reviewed January 2011 What is distal arthrogryposis type 1? Distal arthrogryposis type 1 is a disorder characterized ...

115

The biomechanical evaluation of intramedullary nails in distal femoral shaft fractures.  

PubMed

The biomechanical parameters (torsional rigidity and compressive strength) for three different intramedullary femoral nails, Küntscher (K), Brooker-Wills (BW), and Küntscher Interlocking (KI) were compared in this study. Fractures were created in the femoral shaft distal to the isthmus with sections removed so that pure torsional rigidity and resistance to compression could be measured. The standard K nail provided no torsional rigidity and only minimal resistance to longitudinal compression. The KI was significantly more rigid under compression than either the BW or the K. In torsional resistance the K nail was significantly weaker than either the BW or KI. The K nail does not provide significant resistance to compression or torsion for use in oblique or comminuted fractures. The BW nail probably provides enough resistance to rotation for use in distal fractures, but probably does not provide enough resistance to compression for use in fractures that are prone to shortening. PMID:1537167

Bankston, A B; Keating, E M; Saha, S

1992-03-01

116

Temperature calculation for extruder screws with internal heat pipes  

NASA Astrophysics Data System (ADS)

One possibility of directly influencing the temperature profile in an extruder is by tempering the screw. This method is currently used in double-screw extrusion and in certain specialized applications in the field of single-screw extrusion. Significant possibilities of influencing the temperature have been shown, for example, while processing PVC on counterrotating double-screw extruders [1]. However, until now, it has not been possible to theoretically model this effect. This paper will thus introduce a mathematical model which describes the effect of internal screw tempering on the temperature gradient of the material in the extruder, allowing processes using tempered screws to be better designed and dimensioned.

Lakemeyer, C.; Schöppner, V.

2014-05-01

117

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

Code of Federal Regulations, 2010 CFR

...Glass-Steagall Act § 250.410 Interlocking relationships between bank and its commingled investment...Act of 1933 in view of the interlocking relationships that would exist between the bank and...firm or organization to engage in the business of receiving deposits, subject to...

2010-01-01

118

Distal Radius Fracture (Broken Wrist)  

MedlinePLUS

... the distal radius can break include: • Intra-articular fracture. A fracture that extends into the wrist joint. (“Articular” means “joint.”) • Extra-articular fracture. A fracture that does not extend into the ...

119

Imaging of the Distal Airways  

PubMed Central

Imaging techniques of the lung continues to advance with improving ability to image the more distal airways. Two imaging techniques are reviewed, computerized tomography and magnetic resonance with hyperpolarized helium-3. PMID:19962040

Tashkin, Donald P.; de Lange, Eduard E.

2009-01-01

120

Screw expander for light duty diesel engines  

NASA Technical Reports Server (NTRS)

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.

1983-01-01

121

Biomechanical Analysis of Differing Pedicle Screw Insertion Angles  

PubMed Central

Background Pedicle screw fixation to stabilize lumbar spinal fusion has become the gold standard for posterior stabilization. A significant percentage of surgical candidates are classified as obese or morbidly obese. For these patients, the depth of the incisions and soft tissue makes it extremely difficult to insert pedicle screws along the pedicle axis. As such, the pedicle screws could only be inserted in a much more sagittal axis. However, biomechanical stability of the angled screw insertion has been controversial. We hypothesized that the straight or parallel screw was a more stable construct compared to the angled or axially inserted screw when subjected to caudal cyclic loading. Methods We obtained 12 fresh frozen lumbar vertebrae from L3 to L5 from five cadavers. Schantz screws (6.0mm) were inserted into each pedicle, one angled and along the axis of the pedicle and the other parallel to the spinous process. Fluoroscopic imaging was used to guide insertion. Each screw was then subjected to caudal cyclic loads of 50N for 2000 cycles at 2Hz. Analysis of initial damage, initial rate, and total damage during cyclic loading was undertaken. Findings Average total fatigue damage for straight screws measured 0.398±0.38 mm, and 0.689±0.96 mm for angled screws. Statistical analysis for total fatigue damage ratio of angled to straight screws revealed that a significant stability was achieved in straight- screw construct (p<0.03). Interpretation This study showed that straight screw insertion results in a more stable pedicle-screw construct. The angled screw insertion technique resulted in more scattered values of damage indicating that the outcome from the angled screw fixation is less predictable. This validates the use of this technique to implant pedicle screws across the axis of the pedicle rather than along the axis, (parallel to the midline sagittal line), and has broad implications in instrumented posterior lumbar spinal surgery. PMID:17208340

Sterba, William; Kim, Do-Gyoon; Fyhrie, David P.; Yeni, Yener N.; Vaidya, Rahul

2007-01-01

122

Apparatus to test insertion and removal torque of bone screws.  

PubMed

This paper describes affordable equipment for testing bone screw torque, corresponding to ASTM standard F543-00 for testing metallic medical bone screws. Correct testing of thin and long bone screws is essential due to screw failures during insertion and removal of the screws. Furthermore, insertion torque is an important factor in predicting fixation strength, screw pull-out force and effects of surface treatment of screws. The capability of the custom-built tester was determined using polytetrafluoroethylene and wood disc samples and bone screws. Bovine cortical bones allowed testing to the failure limit, i.e. the torque increased in long screws to the fracture limit. For 2.7 and 3.5 mm thick self-tapping cortical bone screws, the failure torques were 30-50 per cent higher than the minimum values required by the standard (1.0 and 2.3 N m respectively). The equipment provided reproducible results and fulfilled the ASTM standard very well. Preliminary testing with amorphous diamond coated bone screws showed good durability of the coating and on average 10-15 per cent lower torque values compared with uncoated screws. The equipment can be used to measure insertion and removal torques as described in the standard. Furthermore, it also allows testing of normal screws and bolts. PMID:14702987

Koistinen, A; Santavirta, S; Lappalainen, R

2003-01-01

123

Transmission of a Screw Dislocation Across a Coherent, Nonslipping Interface  

E-print Network

1 Transmission of a Screw Dislocation Across a Coherent, Nonslipping Interface Yao Shen materials (B), Energy methods (B), Transmission across interfaces Abstract Current research of slip transmission of a screw dislocation across a coherent, non-slipping interface is presented

Anderson, Peter M.

124

Rescheduling Dense Train Traffic over Complex Station Interlocking Areas  

NASA Astrophysics Data System (ADS)

Railway rescheduling is the task of restoring feasibility in case of disturbances and limiting the propagation of delays through a railway network. This task becomes more difficult when dealing with complex interlocking areas, since operational rules constrain the passage of trains through short track sections. This paper presents a detailed microscopic representation of the railway network that is able to tackle the complexity of a station area with multiple conflicting routes and high service frequency. Two alternative graph formulations are presented to model the incompatibility between routes: one based on track sections and another based on the aggregation of track sections into station routes. An extensive computational study gives useful information on the performance of the two formulations for different disturbance scenarios.

Corman, Francesco; Goverde, Rob M. P.; D'Ariano, Andrea

125

Availability Analysis of the Ventilation Stack CAM Interlock System  

SciTech Connect

Ventilation Stack Continuous Air Monitor (CAM) Interlock System failure modes, failure frequencies and system availability have been evaluated for the RPP. The evaluation concludes that CAM availability is as high as assumed in the safety analysis and that the current routine system surveillance is adequate to maintain this availability. Further, requiring an alarm to actuate upon CAM failure is not necessary to maintain the availability credited in the safety analysis, nor is such an arrangement predicted to significantly improve system availability. However, if CAM failures were only detected by the 92-day functional tests required in the Authorization Basis (AB), CAM availability would be much less than that credited in the safety analysis. Therefore it is recommended that the current surveillance practice of daily simple system checks, 30-day source checks and 92-day functional tests be continued in order to maintain CAM availability.

YOUNG, J.

2000-01-05

126

A Novel Pedicle Screw with Mobile Connection: A Pilot Study  

PubMed Central

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

Oshima, Masashi; Ajiro, Yasumitsu; Uei, Hiroshi

2014-01-01

127

A technique for retrieving fractured implant screws.  

PubMed

The use of dental implants as a source of support and retention for fixed restorations is common. This report describes the use of a fragment removal instrument together with the use of ultrasonic instrumentation to retrieve a screw fragment. PMID:24268685

Imam, Ahmad Y; Moshaverinia, Alireza; Chee, Winston W L; McGlumphy, Edwin A

2014-01-01

128

Visuality in The Turn of the Screw: \\  

Microsoft Academic Search

Scarry is referring to the half-formed, transitory, vanishing quality of ghosts—a quality shared, more or less, by any mental image we might choose to form in the mind's eye. In this sense The Turn of the Screw is a perfect ghost story. It is a story about seeing ghosts, about picturing them, and perhaps about imagining them altogether. In fact,

Josh Rothman

129

Radiographic study of iliac screw passages  

PubMed Central

Background The optimal iliac screw path was determined to provide references for lumbosacral-pelvic reconstruction. Methods Radiographic data of 100 patients with normal pelvis were selected for this study. Four paths were designed. Paths A, B, and C were from the starting point of the crossing point of the chiotic line and posterior iliac crest (CLIC, located at 24.0 mm above the posterior superior iliac spine) to the upper edge of the acetabulum, anterior inferior iliac spine, and acetabulum center, respectively. Path D was from the starting point of the posterior superior iliac spine to the anterior inferior iliac spine. The lengths of the different paths of screw passage and bone plate thicknesses of two narrow places were measured and analyzed. Results Paths A, B, and D were approximately equal in length, but the thickness of the iliac plate in path A was significantly thicker than those in paths B and D. No significant difference was found between the iliac thickness of paths A and C, but the passage length of path A was significantly longer than that of path C. Conclusion Path A had the longest passage length and thickest iliac plate and could accommodate the relatively longest and thickest iliac screw. Thus, path A was the optimal iliac screw passage. PMID:24885171

2014-01-01

130

Screw-Together George W. Hart  

E-print Network

Screw-Together Cube George W. Hart Dept. Computer Science Stony Brook University http related forms. Martin Gardner credits a related three-piece cube dissection to John E. Morse [1]. William and George Miller is commercially available at [3]. I came to appreciate the elegance of this family of forms

131

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

SciTech Connect

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

Tighe, R.; /SLAC

2011-08-31

132

Traumatic Distal Ulnar Artery Thrombosis  

PubMed Central

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

Karaarslan, Ahmet A.; Karakasl?, Ahmet; Mayda, Aslan; Karc?, Tolga; Aycan, Hakan; Kobak, Senol

2014-01-01

133

Surgical screw segmentation for mobile C-arm CT devices  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

134

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

PubMed

Pedicle screws have become the gold standard of spinal instrumentation over the past decade owing to their biomechanical superiority. Despite their advantages, pedicle screw instrumentation is potentially dangerous, and surgeons wish to improve accuracy of screw placement to avoid complications associated with screw misplacement. The anatomy of the pedicles is variable throughout the spine, and several landmarks and trajectories have been suggested to aid safe placement of pedicle screws in the spine. Several techniques such as x-ray and computed tomography scan imaging coupled with computer-aided navigation are available to improve accuracy of screw insertion. Intraoperative neuromonitoring with the help of triggered electromyographic recordings has evolved as an objective evidence of assessing pedicle breach and proximity of the screw to neural structures. While all imaging and electrophysiological modalities should be applied on an individualized basis, finally no adjunctive technique can fully replace the need for surgical expertise and experience. PMID:23207586

Joglekar, Siddharth B; Mehbod, Amir A

2012-12-01

135

Global ice-sheet system interlocked by sea level  

NASA Astrophysics Data System (ADS)

Denton and Hughes (1983, Quaternary Research20, 125-144) postulated that sea level linked a global ice-sheet system with both terrestrial and grounded marine components during late Quaternary ice ages. Summer temperature changes near Northern Hemisphere melting margins initiated sea-level fluctuations that controlled marine components in both polar hemispheres. It was further proposed that variations of this ice-sheet system amplified and transmitted Milankovitch summer half-year insolation changes between 45 and 75°N into global climatic changes. New tests of this hypothesis implicate sea level as a major control of the areal extent of grounded portions of the Antarctic Ice Sheet, thus fitting the concept of a globally interlocked ice-sheet system. But recent atmospheric modeling results ( Manabe and Broccoli, 1985, Journal of Geophysical Research90, 2167-2190) suggest that factors other than areal changes of the grounded Antarctic Ice Sheet strongly influenced Southern Hemisphere climate and terminated the last ice age simultaneously in both polar hemispheres. Atmospheric carbon dioxide linked to high-latitude oceans is the most likely candidate ( Shackleton and Pisias, 1985, Atmospheric carbon dioxide, orbital forcing, and climate. In "The Carbon Cycle and Atmospheric CO 2: Natural Variations Archean to Present" (E. T. Sundquest and W. S. Broecker, Eds.), pp. 303-318. Geophysical Monograph 32, American Geophysical Union, Washington, D.C.), but another potential influence was high-frequency climatic oscillations (2500 yr). It is postulated that variations in atmospheric carbon dioxide acted through an Antarctic ice shelf linked to the grounded ice sheet to produce and terminate Southern Hemisphere ice-age climate. It is further postulated that Milankovitch summer insolation combined with a warm high-frequency oscillation caused marked recession of Northern Hemisphere ice-sheet melting margins and the North Atlantic polar front about 14,000 14C yr B.P. This permitted renewed formation of North Atlantic Deep Water, which could well have controlled atmospheric carbon dioxide ( W. S. Broecker, D. M. Peteet, and D. Rind, 1985, Nature ( London) 315, 21-26). Combined melting and consequent sea-level rise from the three warming factors initiated irreversible collapse of the interlocked global ice-sheet system, which was at its largest but most vulnerable configuration.

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

1986-07-01

136

Distal phalangectomy for mallet toe  

Microsoft Academic Search

We retrospectively reviewed 24 patients with 37 mallet toes from two centres who had undergone distal phalangectomy. The mean follow up was 3.8 years. Patients were reviewed by an independent assessor with regard to pain relief, cosmetic acceptability and overall satisfaction.All patients had satisfactory pain relief but one patient felt that the toe stump was cosmetically acceptable. The overall satisfaction

S Raja; J. L Barrie; A. A Henderson

2003-01-01

137

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Standard No. 102; Transmission shift position sequence, starter interlock, and transmission braking effect. 571.102 Section... § 571.102 Standard No. 102; Transmission shift position sequence,...

2010-10-01

138

New beam-charge interlock system for radiation safety at the KEKB injector linac  

NASA Astrophysics Data System (ADS)

A new beam-charge interlock system is under development for radiation safety and machine protection at the KEKB injector linac. A hardware-based interlock system is required instead of the present software-based interlock system in order to boost its reliability. This system restricts the integrated amount of beam charges delivered to four different storage rings. The beam charges are measured using wall-current monitors and detection electronics at six locations along the linac. The detection electronics independently transmits a beam-abort request through a twisted hardwire cable directly to the safety control system of the linac, when the integrated amount of beam charges exceeds a certain threshold level prescribed for each location. We describe the characteristics and performance of the new beam-charge interlock system along with the details of the experimental tests.

Suwada, T.; Kadokura, E.; Satoh, M.; Furukawa, K.

2008-02-01

139

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

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Standard No. 102; Transmission shift position sequence, starter interlock, and transmission braking effect. 571.102 Section... § 571.102 Standard No. 102; Transmission shift position sequence,...

2012-10-01

140

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

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Standard No. 102; Transmission shift position sequence, starter interlock, and transmission braking effect. 571.102 Section... § 571.102 Standard No. 102; Transmission shift position sequence,...

2011-10-01

141

Engineering of interlocked DNA G-quadruplexes as a robust scaffold  

PubMed Central

Interlock is a structural element in DNA G-quadruplexes that can be compared with the commonly used complementary binding of ‘sticky ends’ in DNA duplexes. G-quadruplex interlocking can be a basis for the assembly of higher-order structures. In this study, we formulated a rule to engineer (3 + 1) interlocked dimeric G-quadruplexes and established the folding topology of the designed DNA sequences by nuclear magnetic resonance spectroscopy. These interlocked G-quadruplexes are very stable and can serve as compact robust scaffolds for various applications. Different structural elements can be engineered in these robust scaffolds. We demonstrated the anti-HIV inhibition activity of the newly designed DNA sequences. PMID:23275539

Phan, Anh Tuan; Do, Ngoc Quang

2013-01-01

142

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

PubMed

PURPOSE OF THE STUDY To present the results of surgical repair of ruptures of the distal tendon of the biceps brachii muscle and thus show the adequacy of this treatment. MATERIAL Between 1987 and 2006, 19 patients had surgery for distal biceps tendon rupture. Only one side was affected in each patient. All patients were men between 28 and 69 years (average age, 47.5 years) at the time of injury (surgery). When the patients were evaluated at the end of 2007, 18 patients were included, because one died a year after surgery. METHODS The surgical repair always included a single-incision anatomical reattachment into the radial tuberosity. In 11 patients, a modified Mac Reynolds method with screw and washer fixation was used; in seven patients the insertion was fixed with Mitek anchors and, in one, it was sutured to the adjacent soft tissues. The average follow-up was 7 years (range, 1 to 20.5 years). The patients were evaluated for the cause of injury, their physical activity, age, dominance of the injured arm, surgical procedure and complications. RESULTS In 18 patients surgical repair was done early and, in one, at 16 days after injury. In all of them the tendon was detached from its site of insertion, but never torn. The intra-operative complications included, in one patient, bleeding owing to iatrogenic damage to a branch of the brachial artery, and difficult separation of the tendon due to its previous healed injury in another patient. Early post-operative complications included superficial skin necrosis in one patient and transient neurological deficit of the dorsal brand of the radial nerve and of the lateral cutaneous nerve of the forearm in two and one patient, respectively. The late complications were heterotropic ossification in three patients and screw migration in the one treated by the Mac Reynolds method. Excellent results were recorded in 11 patients (61 %), and good outcomes with a slight restriction of motion or muscle strength not limiting the patient's physical activities were in six (33.5 %) patients; only one patient (5.5 %) experienced pain on moderate exercise and had recurrent heterotropic ossification. Apart from this condition, there was no difference in the frequency of complications associated with the method used. DISCUSSION Only sparse information on distal biceps tendon ruptures has been available in the relevant Czech literature and, if so, only small groups with short follow-ups have been involved. Conservative treatment or the methods of non-anatomical reattachment have poor functional outcomes. Much better results are achieved by anatomical reattachment. Based on our experience with the Mac Reynolds technique, an anterior single-incision approach using fixation with Mitek anchors can be recommended. CONCLUSIONS Early surgical repair involving anatomical reattachment from the anterior singleincision approach with two Mitek anchors is recommended when a rupture of the distal tendon insertion of the biceps brachii is diagnosed. Key words: biceps radii muscle, biceps tendon injury, tendon fixation, bone screw and washer use. PMID:19268049

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

2009-02-01

143

Effectiveness of Ignition Interlocks for Preventing Alcohol-Impaired Driving and Alcohol-Related Crashes  

Microsoft Academic Search

A systematic review of the literature to assess the effectiveness of ignition interlocks for reducing alcohol-impaired driving and alcohol-related crashes was conducted for the Guide to Community Preventive Services (Community Guide). Because one of the primary research issues of interest—the degree to which the installation of interlocks in offenders' vehicles reduces alcohol-impaired driving in comparison to alternative sanctions (primarily license

Randy W. Elder; Robert Voas; Doug Beirness; Ruth A. Shults; David A. Sleet; James L. Nichols; Richard Compton

2011-01-01

144

Effects of administrative ignition interlock license restrictions on drivers with multiple alcohol offenses  

Microsoft Academic Search

This study investigated, under real-world conditions, whether a statewide 2-year administrative ignition interlock license\\u000a restriction program in Maryland was effective in reducing subsequent alcohol-related traffic violations among multiple offenders\\u000a and whether any reductions in recidivism could be maintained after the program ended and interlock license restrictions were\\u000a removed. A total of 1,927 drivers eligible for relicensure were randomly assigned to

William J. Rauch; Eileen M. Ahlin; Paul L. Zador; Jan M. Howard; G. Doug Duncan

2011-01-01

145

Helical Screw Expander Evaluation Project. Final report  

Microsoft Academic Search

A functional 1-MW geothermal electric power plant that featured a helical screw expander was produced and then tested in Utah in 1978 to 1979 with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing operation on two-phase geothermal fluids. The Project also produced a computer-equipped data system, an instrumentation and control

McKay

1982-01-01

146

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

PubMed Central

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

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

2014-01-01

147

Interlocked DNA nanostructures controlled by a reversible logic circuit  

PubMed Central

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

Li, Tao; Lohmann, Finn; Famulok, Michael

2014-01-01

148

An intensity ratio of interlocking loops determines circadian period length  

PubMed Central

Circadian clocks allow organisms to orchestrate the daily rhythms in physiology and behaviors, and disruption of circadian rhythmicity can profoundly affect fitness. The mammalian circadian oscillator consists of a negative primary feedback loop and is associated with some ‘auxiliary’ loops. This raises the questions of how these interlocking loops coordinate to regulate the period and maintain its robustness. Here, we focused on the REV-ERB?/Cry1 auxiliary loop, consisting of Rev-Erb?/ROR-binding elements (RORE) mediated Cry1 transcription, coordinates with the negative primary feedback loop to modulate the mammalian circadian period. The silicon simulation revealed an unexpected rule: the intensity ratio of the primary loop to the auxiliary loop is inversely related to the period length, even when post-translational feedback is fixed. Then we measured the mRNA levels from two loops in 10-mutant mice and observed the similar monotonic relationship. Additionally, our simulation and the experimental results in human osteosarcoma cells suggest that a coupling effect between the numerator and denominator of this intensity ratio ensures the robustness of circadian period and, therefore, provides an efficient means of correcting circadian disorders. This ratio rule highlights the contribution of the transcriptional architecture to the period dynamics and might be helpful in the construction of synthetic oscillators. PMID:25122753

Yan, Jie; Shi, Guangsen; Zhang, Zhihui; Wu, Xi; Liu, Zhiwei; Xing, Lijuan; Qu, Zhipeng; Dong, Zhen; Yang, Ling; Xu, Ying

2014-01-01

149

Distal Oblique Bundle Reconstruction and Distal Radioulnar Joint Instability  

PubMed Central

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

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

2013-01-01

150

Distal Tibial Fractures: Intramedullary Nailing  

Microsoft Academic Search

\\u000a Abstract\\u000a   The tibia is an exposed bone with vulnerable soft tissue coverage and is therefore predisposed to local soft tissue problems\\u000a and delayed bone healing. The objective in distal tibial fracture treatment is to achieve stable fixation patterns with a\\u000a minimum of soft-tissue affection. Thus, the risk of soft tissue breakdown and bone healing complications is more likely related\\u000a to

Andreas H. Ruecker; Michael Hoffmann; Martin E. Rupprecht; Johannes M. Rueger

2009-01-01

151

Biomechanical stability of bioabsorbable screws for fixation of acetabular osteotomies.  

PubMed

The purpose of this study was to compare the biomechanical stability of triple innominate osteotomies fixed with either bioabsorbable or stainless steel screws. Triple innominate osteotomies were performed on composite hemipelves and fixed with either three 4.5-mm bioabsorbable screws or three stainless steel 4.5-mm screws. Two screws were placed from the iliac wing into the acetabular fragment, and 1 screw was placed from below the acetabular fragment into the iliac wing. Eight specimens for each screw type were biomechanically tested in an anatomical position (replicating weight bearing) and in a flexed and abducted position (replicating spica cast positioning). Specimens were cyclically loaded between 10 and 450 N to simulate the hip contact force in this population. Lower screws were then removed, and specimens were tested under identical conditions. Fragment displacement (mm) and construct stiffness (N/mm) were compared with a 2-way analysis of variance (P < 0.05). There were no significant differences between materials for fragment displacement or construct stiffness. Anatomical position showed significantly less displacement than spica position for both materials. Initial displacement in the spica position was significantly less during lower loads for stainless steel fixation. Bioabsorbable screws demonstrate comparable biomechanical stability to stainless steel screws in anatomical and spica positions at physiological loads. Flexion and abduction of the femur adversely affect the stability of the construct for both materials. Bioabsorbable screws behave similarly to steel screws when stabilizing triple innominate osteotomies and would have the advantage of not requiring a second surgery for screw removal. Confirmation of biocompatibility should be completed before widespread clinical application. PMID:17414017

Adamczyk, Mark J; Odell, Tim; Oka, Richard; Mahar, Andrew T; Pring, Maya E; Lalonde, François D; Wenger, Dennis R

2007-01-01

152

Surgical Treatment for Unstable Distal Clavicle Fracture with Micromovable and Anatomical Acromioclavicular Plate  

PubMed Central

Between 2006 and 2009, 18 patients of distal clavicle fracture were treated with micro-movable and anatomical acromioclavicular plate (MAAP) in our department. According to the Neer's classification, all cases were unstable with type IIA (12 cases) and type IIB (6 cases). Functional outcome was evaluated using the Karlsson's criteria. The mean follow-up was 18 months (range, 12-36months). No postoperative plate screws complication was observed. Osseous union could be achieved at a mean time of 12 weeks after operation in 18 patients (range, 8 -16 weeks). According to Karlsson's criteria, radiographic appearances and postoperative shoulder functional recovery revealed a good and excellent rate in these cases. We conclude that surgical treatment using MAAP seems to be a good option for unstable type II fractures of the distal clavicle. This technique allows for reliable fixation with early functional exercises and functional recovery. PMID:22701337

Liu, Qingjun; Miao, Jianyun; Lin, Bin; Lian, Kejian

2012-01-01

153

Simultaneous Dorsal Base Fracture and FDP Avulsion of Distal Phalanx of the Little Finger.  

PubMed

Avulsion injury of the flexor digitorum profundus (FDP) with concomitant fracture of the distal phalanx dorsal base is uncommon. Simultaneous avulsion fractures of the insertion of this tendon associated with rupture of the tendon from the bony fragment and combination with dorsal base fracture is very rare and also complicated. A 36- year- old man fell and injured his right little finger. FDP avulsion with simultaneous dorsal base fracture (containing extensor Tendon insertion) was detected. Our surgical repair by a single midlateral incision the avulsed fragment was replaced on the palmar base of the distal phalanx and successfully immobilized with 1.5 mm screw. After three months, patient had 20 degrees range of motion in the DIP joint. The digit was pain free and also relatively functional. It seems that FDP avulsion classification need to be extended and include this uncommon type as described in this case report for better management of these uncommon type. PMID:25207316

Bazavar, Mohammadreza; Rouhani, Alireza; Tabrizi, Ali

2014-03-01

154

Experimental investigation of the use of drag reducing agents in conjunction with twin-screw multiphase pumps  

E-print Network

: 1) simple screw pump, 2) single screw pump, 3) twin-screw pump, and 4) three-screw pump. The simple screw pump is an extensive version of the axial-flow, or propeller, pump. It is based on the principle of Archimedes screw and has been developed...: 1) simple screw pump, 2) single screw pump, 3) twin-screw pump, and 4) three-screw pump. The simple screw pump is an extensive version of the axial-flow, or propeller, pump. It is based on the principle of Archimedes screw and has been developed...

Carrillo Plazas, Gabriel D

2012-06-07

155

Global ice-sheet system interlocked by sea level  

SciTech Connect

Denton and Hughes postulated that sea level linked a global ice-sheet system with both terrestrial and grounded marine components during later Quaternary ice ages. Summer temperature changes near Northern Hemisphere melting margins initiated sea-level fluctuations that controlled marine components in both polar hemispheres. It was further proposed that variations of this ice-sheet system amplified and transmitted Milankovitch summer half-year insolation changes between 45 and 75/sup 0/N into global climatic changes. New tests of this hypothesis implicate sea level as a major control of the areal extent of grounded portions of the Antarctic Ice Sheet. But factors other than areal changes of the grounded Antarctic Ice Sheet may have strongly influenced Southern Hemisphere climate and terminated the last ice age simultaneously in both polar hemispheres. Atmospheric carbon dioxide linked to high-latitude oceans is the most likely candidate, but another potential influence was high-frequency climatic oscillations. It is postulated that variations in atmospheric carbon dioxide acted through an Antarctic ice shelf linked to the grounded ice sheet to produce and terminate Southern Hemisphere ice-age climate. It is further postulated that Milankovitch summer insolation combined with a warm-high frequency oscillation caused marked recession of Northern Hemisphere ice-sheet melting margins and the North Atlantic polar front about 14,000 /sup 14/C yr B.P. This permitted renewed formation of North Atlantic Deep Water, which could well have controlled atmospheric carbon dioxide. Combined melting and consequent sea-level rise from the three warming factors initiated irreversible collapse of the interlocked global ice-sheet system, which was at its largest but most vulnerable configuration.

Denton, G.H.; Hughes, T.J.; Karlen, W.

1986-01-01

156

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

PubMed Central

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

Lee, Sandra; Vaidya, Rahul

2008-01-01

157

Comparison of Outcomes after Atlantoaxial Fusion with Transarticular Screws and Screw-Rod Constructs  

PubMed Central

Objective The purpose of this study was to compare the radiological and neurological outcomes between two atlantoaxial fusion method for atlantoaxial stabilization; C1 lateral mass-C2 pedicle screws (screw-rod constructs, SRC) versus C1-2 transarticular screws (TAS). Methods Forty-one patients in whom atlantoaxial instability was treated with atlantoaxial fixation by SRC group (27 patients, from March 2005 to May 2011) or TAS group (14 patients, from May 2000 to December 2005) were retrospectively reviewed. Numeric rating scale (NRS) for pain assessment, Oswestry disability index (ODI), and Frankel grade were also checked for neurological outcome. In radiologic outcome assessment, proper screw position and fusion rate were checked. Perioperative parameters such as blood loss during operation, operation time, and radiation exposure time were also reviewed. Results The improvement of NRS and ODI were not different between both groups significantly. Good to excellent response in Frankel grade is shown similarly in both groups. Proper screw position and fusion rate were also observed similarly between two groups. Total bleeding amount during operation is lesser in SRC group than TAS group, but not significantly (p=0.06). Operation time and X-ray exposure time were shorter in SRC group than in TAS group (all p<0.001). Conclusion Both TAS and SRC could be selected as safe and effective treatment options for C1-2 instability. But the perioperative result, which is technical demanding and X-ray exposure might be expected better in SRC group compared to TAS group. PMID:25132931

Kim, Ji Yong; Oh, Chang Hyun; Park, Hyeong-Chun; Seo, Hyun Sung

2014-01-01

158

Screw dislocations in GaN  

SciTech Connect

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.

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

2002-02-15

159

Joining mechanism with stem tension and interlocked compression ring  

DOEpatents

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.

James, Allister W.; Morrison, Jay A.

2012-09-04

160

A new volar plate DiPhos-RM for fixation of distal radius fracture: preliminary report.  

PubMed

We analyzed the efficiency of a new plate DiPhos-RM in CFR-PEEK [carbon-fiber-reinforced poly (etheretherketone)] for the volar fixation of distal radius fractures. The new plate's composition has the advantage of x-ray absolute transparency, therefore allowing to monitor the healing of the fracture. The desired combination of high strength and low rigidity is obtained through the use of the polymer composites CFR-PEEK. In this preliminary study (from March 2012 to June 2012), 10 cases of intra-articular distal radius fractures were treated with DiPhos-RM produced by Lima Corporate (Italy). The fractures were classified according to the AO classification, 4 fractures were type C1, 3 type C2, and 3 were A2. A preoperative computed tomography scan was carried out in all patients. One patient also underwent a postoperative computed tomography scan. Grip strength, range of motion, and DASH score were evaluated at follow-up. There were no cases of hardware failure. Specifically, no loss of position or alignment of fixed-angle locking screws or breakage of the plate were observed. Radiographic union was present at an average of 6 weeks (range, 5 to 8 wk). The overall preliminary experience with this new plate is favorable. The new plate is easy to apply and provides the surgeon dual options of fixed-angle or variable-angle screws. It was rigid enough to maintain the reduction also in AO type C articular fractures. PMID:23423235

Tarallo, Luigi; Mugnai, Raffaele; Adani, Roberto; Catani, Fabio

2013-03-01

161

Optimized rotor pitch distributions for screw spindle vacuum pumps  

Microsoft Academic Search

Screw spindle vacuum pumps are characterised by a high suction performance and the ability to achieve high pressure ratios. Screw spindle vacuum pumps have varying progressions for the rotor pitch gradient, depending on the manufacturer. From a scientific point of view, the question arises which rotor gradient along the rotors has to be preferred for a particular set of operating

D. Pfaller; A. Brümmer; K. Kauder

2011-01-01

162

Transmission of a Screw Dislocation Across a Coherent, Slipping Interface  

E-print Network

1 Transmission of a Screw Dislocation Across a Coherent, Slipping Interface Yao Shen(a) and Peter M of interfacial sliding during dislocation transmission. A straight screw dislocation parallel to a bimaterial. Interfacial sliding is predicted to increase the critical applied shear crit of interfaces for transmission

Anderson, Peter M.

163

FORMING PROCESS OF SCREW SPIKE IN DOUBLE CONFIGURATION  

Microsoft Academic Search

Summary. In this paper technology of screw spikes manufacturing, based on the flashless forging and hot rolling in double configuration, is presented. The forging takes place in closed dies and the obtained workpiece is rolled in its middle part on cross-wedge rolling mill in order to make screw thread. As the result of this process, it is possible to eliminate

COMPLAS VIII; S. Wero?ski; Andrzej Gontarz; Zbigniew Pater

164

Bicondylar Hoffa Fracture Successfully Treated with Headless Compression Screws  

PubMed Central

Bicondylar coronal plane fracture, eponymically named Hoffa fractures, is an extremely rare injury. We present a case of isolated unilateral bicondylar Hoffa fracture that was successfully treated with open reduction and internal fixation using headless compression screws with satisfactory results. We inserted posteroanteriorly oriented Acutrak screws perpendicular to the fracture plane via lateral parapatellar arthrotomy, which provided excellent compression across the fracture. PMID:25140263

Kuroda, Ryosuke; Kurosaka, Masahiro

2014-01-01

165

Application studies of CFRTP hexagon socket head cap screws  

NASA Astrophysics Data System (ADS)

PPS thermoplastic CFRP is used to fabricate screws via injection molding; these samples were tested for tensile strength and torque vs axial tension. Attention was given to the effects of various lubricants. When MoS2 was applied to the screw's threading, its axial tension increased from 10 to 16 kN.

Sano, Akihiko; Matsumoto, Masaru

166

DESIGN OF OIL-LESS HELICAL TWIN SCREW MACHINES  

Microsoft Academic Search

A twin screw machine is described as oil-less when the working chamber between the contacting helical rotors and the casing, which is usually flooded by oil, operates with no oil or a very small quantity of oil injected in it. Such a mode of operation has been shown to be viable in two experimental projects in which three screw machine

Ian K Smith; Ahmed Kovaèeviæ

167

MATHEMATICAL ANALYSIS OF OIL INJECTED TWIN SCREW COMPRESSOR  

Microsoft Academic Search

Mathematical analysis of oil injected twin-screw compressor is carried out on the basis of the laws of perfect gas, and standard thermodynamic relations. Performance of an oil injected twin-screw compressor depends on a large number of design parameters. A computer model for calculating compressor performance and to validate the results with experimental data is developed. The flow coefficients required to

N. Seshaiah; R. K. Sahoo

168

Performance Analysis of Oil Injected Twin Screw Compressor  

Microsoft Academic Search

Oil injected twin-screw air compressors are widely used for medium pressure applications in cryogenic industries. Conversion of these compressors for helium applications is in great demand due to their inherent advantages. A mathematical model of an oil injected twin-screw compressor has been constructed basing on the laws of perfect gas and standard thermodynamic relations to evaluate compressor efficiencies. The complete

N. Seshaiah; Subrata Kr; Ranjit Kr; Sunil Kr

2006-01-01

169

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

SciTech Connect

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

Branum, J.D.

1981-10-20

170

Distal Myopathy with Rimmed Vacuoles  

PubMed Central

Distal myopathy with rimmed vacuoles (DMRV), is an autosomal recessive disorder with early adult onset, displays distal dominant muscular involvement and is characterized by the presence of numerous rimmed vacuoles in the affected muscle fibers. The pathophysiology of DMRV has not been clarified yet, although the responsible gene was identified as that encoding UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase involved in the biosynthesis of sialic acids. To identify defective carbohydrate moieties of muscular glycoproteins from DMRV patients, frozen skeletal muscle sections from seven patients with DMRV, as well as normal and pathological controls, were treated with or without sialidase or N-glycosidase F followed by lectin staining and lectin blotting analysis. The sialic acid contents of the O-glycans in the skeletal muscle specimens from the DMRV patients were also measured. We found that Arachis hypogaea agglutinin (PNA) lectin reacted strongly with sarcolemmal glycoproteins in the DMRV patients but not with those in control subjects. ?-Dystroglycan from the DMRV patients strongly associated with PNA lectin, although that from controls did not. The sialic acid level of the O-glycans in the DMRV muscular glycoproteins with molecular weights of 30 to 200 kd was reduced to 60 to 80% of the control level. The results show that impaired sialyl O-glycan formation in muscular glycoproteins, including ?-dystroglycan, occurs in DMRV. PMID:15793292

Tajima, Youichi; Uyama, Eiichiro; Go, Shinji; Sato, Chihiro; Tao, Nodoka; Kotani, Masaharu; Hino, Hirotake; Suzuki, Akemi; Sanai¶, Yutaka; Kitajima, Ken; Sakuraba, Hitoshi

2005-01-01

171

Performance of Screw Compressor for Small-Capacity Helium Refrigerators  

NASA Astrophysics Data System (ADS)

A helium compressor is one of the important components comprising a cryogenic refrigerator. The purpous of this investigation is to develop a new small-capacity helium screw compressor. The performance of a single-stage compressor at high compression ratio and the cooling performance of the compressor are investigated. A semi-hermetic screw compressor with new profile screw rotors, with which high performance can be obtained, is utilized in this investigation. Lubricating oil is applied to cool the compressor motor and the compressed gas. As a result, an overall isentropic efficiency of 80% is obtained when helium is compressed to a compression ratio of 19.8 with a single-stage screw compressor. At the same time, the temperature of a compressor motor and discharge gas can be maintained at low levels. Therefore, it is found that a single-stage screw compressor can compress helium to high compression ratio.

Urashin, Masayuki; Matsubara, Katsumi; Izunaga, Yasushi

172

A Surgical Method for Determining Proper Screw Length in ACDF  

PubMed Central

Objective We describe a surgical tool that uses the distractor pin as a reference for determining proper screw length in ACDF. It is critical that screw purchase depth be as deep as possible without violating or penetrating the posterior cortical wall, which ensures strong pull out strength. Methods We enrolled 81 adult patients who underwent ACDF using an anterior cervical plate from 2010 to 2012. Patients were categorized into Groups A (42 patients: retractor pin used as a reference for screw length) and B (39 patients: control group). Intraoperative lateral x-rays were taken after screwing the retractor pin to confirm the approaching vertebral level. The ratio of retractor pin length to body anteroposterior (A-P) diameter was measured as a reference. Proper screw length was determined by comparison to the reference. Results The average distance from screw tip to posterior wall was 3.0±1.4mm in Group A and 4.1±2.3mm in Group B. The ratio of screw length to body sagittal diameter was 86.2±5.7% in Group A and 80.8±9.0% in Group B. Screw length to body sagittal diameter ratios higher than 4/5 occurred in 33 patients (90%) in Group A and 23 patients (59%) in Group B. No cases violated the posterior cortical wall. Conclusion We introduce a useful surgical method for determining proper screw length in ACDF using the ratio of retractor pin length to body A-P diameter as a reference. This method allows for deeper screw purchase depth without violation of the posterior cortical wall.

Park, Hae-Gi; Kang, Moo-Sung; Kim, Kyung-Hyun; Park, Jeong-Yoon; Kim, Keun-Su

2014-01-01

173

Comparison of a New Braid Fixation System to an Interlocking Intramedullary Nail for Tibial Osteotomy Repair in an Ovine Model  

E-print Network

alignment, tibial shaft fractures can be treated by external fixation with a cast, intramedullary (IM) nail) and polymethylmethacrylate bone cement with an interlocking intramedullary (IM) nail fixation in an ovine model. Study DesignComparison of a New Braid Fixation System to an Interlocking Intramedullary Nail for Tibial

Scharer, John E.

174

Effects of Ignition Interlock Devices on DUI Recidivism: Findings from a Longitudinal Study in Hamilton County, Ohio  

Microsoft Academic Search

As demands for more effective legal remedies for drunk driving escalate, a number of states have authorized judges to use breath analyzer ignition interlock devices as an optional sanction in drunk driving cases. This research presents initial findings from a quasi-experimental study designed to evaluate the effectiveness of interlock devices as a deterrent to a repeated drunk driving arrest in

Barbara J. Morse; Delbert S. Elliott

1992-01-01

175

Blistering distal dactylitis caused by Staphylococcus aureus.  

PubMed

Blistering distal dactylitis is a superficial infection of the anterior fat pad on the volar surface of the distal portion of ordinarily a single finger. Although most commonly caused by group A beta-hemolytic streptococci, we report a case of blistering distal dactylitis caused by Staphylococcus aureus involving all the fingers and thumbs of a child. After results of a Gram's stain and culture established the diagnosis, the child responded rapidly to oral amoxicillin trihydrate/clavulanate potassium (Augmentin). Multiple fingers affected in blistering distal dactylitis may be a predictor of S. aureus as the causative agent. PMID:8513687

Norcross, M C; Mitchell, D F

1993-05-01

176

Stability of the noncircular screw pinch  

NASA Astrophysics Data System (ADS)

The magnetohydrodynamic stability of a slightly noncircular screw pinch with arbitrary cross-sectional shape is investigated analytically and numerically using two models: the surface-current model and the force-free model. For the surface-current model the noncircular correction to the instability growth rate is given in analytical form: (1) for the case nq is about or equal to m, where q is the safety factor and m and n are the azimuthal and longitudinal mode numbers of the instability, and (2) for the special case of purely transverse perturbations (n = 0). For the force-free model, the noncircular correction to the marginal stability condition is obtained. This is done analytically for nq is about or equal to m, and for fixed boundary internal modes.

Miller, G.

1980-11-01

177

Screw Compressor Characteristics for Helium Refrigeration Systems  

NASA Astrophysics Data System (ADS)

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. Therefore it is important to understand the isothermal and volumetric efficiencies of these machines to help properly design these compression systems to match the refrigeration process. This presentation summarizes separate tests that have been conducted on Sullair compressors at the Superconducting Super-Collider Laboratory (SSCL) in 1993, Howden compressors at Jefferson Lab (JLab) in 2006 and Howden compressors at the Spallation Neutron Source (SNS) in 2006. This work is part of an ongoing study at JLab to understand the theoretical basis for these efficiencies and their loss mechanisms, as well as to implement practical solutions.

Ganni, V.; Knudsen, P.; Creel, J.; Arenius, D.; Casagrande, F.; Howell, M.

2008-03-01

178

Spline-locking screw fastening strategy  

NASA Technical Reports Server (NTRS)

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

Vranish, John M.

1992-01-01

179

Spline-Locking Screw Fastening Strategy (SLSFS)  

NASA Technical Reports Server (NTRS)

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

Vranish, John M.

1991-01-01

180

Distal realignment (tibial tuberosity transfer).  

PubMed

Although tibial tuberosity (TT) transfer has for many years been the basis of many protocols for the management of patellar instability, the role of pure medial transfer in particular appears to be declining. In contrast, the greater recognition of the importance of patella alta as a predisposing factor to recurrent patellar dislocation has resulted in a resurgence in the popularity of distal TT transfer. When TT transfer is performed, the direction and amount of transfer is based on the patellar height and the lateralization of the TT relative to the trochlear groove. Patellar height is best assessed on a lateral radiograph with the knee in flexion using a ratio that uses the articular surface of the patella in relation to the height above the tibia. Assessment of lateralization of the TT relative to the trochlear groove can be made using either computed tomography or magnetic resonance imaging scans. PMID:22878656

Feller, Julian Ashley

2012-09-01

181

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

PubMed Central

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

2014-01-01

182

[Palmar fixed angle plating systems for instable distal radius fractures].  

PubMed

Internal fixation of distal radius fractures often shows the problem of secondary dislocation due to dorsal comminution and osteoporosis. Although dorsal plating systems provide good stabilization, the intraoperative control of reduction is difficult in the comminuted area with high incidence for the need of cancellous bone graft. Occurrence of extensor tendon complications including tendonitis and rupture is not uncommon. The use of fixed angle devices by a palmar approach has demonstrated the advantage of better visualization and control at the fracture side. The subchondrale support of the articular surface by fixed angle pegs or screws prevents secondary dislocation allowing early mobilization. Better soft tissue coverage is associated with a low complication rate. 62 patients (average age 55 years) were treated with different fixed angel devices according to the fracture type and underwent retrospective evaluation with mean follow-up of 11 months (6-23 months). According to the AO Classification there were 3 A2, 24 A3, 7 B3, 14 C1, 9 C2 und 5 C3 fractures. The majority beside the B3 types and one C3 fracture were dorsally displaced. All of them showed healing without relevant secondary loss of reduction. Mean DASH score reached 19 points. PMID:15205741

Krimmer, H; Pessenlehner, C; Hasselbacher, K; Meier, M; Roth, F; Meier, R

2004-06-01

183

Fracture mechanisms of retrieved titanium screw thread in dental implant.  

PubMed

Titanium and its alloy are increasingly attracting attention for use as biomaterials. However, delayed fracture of titanium dental implants has been reported, and factors affecting the acceleration of corrosion and fatigue have to be determined. The fractured surface of a retrieved titanium screw and metallurgical structures of a dental implant system were analyzed. The outer surface of the retrieved screw had a structure different from that of the as-received screw. It was confirmed that a shear crack initiated at the root of the thread and propagated into the inner section of the screw. Gas chromatography revealed that the retrieved screw had absorbed a higher amount of hydrogen than the as-received sample. The grain structure of a titanium screw, immersed in a solution known to induce hydrogen absorption, showed features similar to those of the retrieved screw. It was concluded that titanium in a biological environment absorbs hydrogen and this may be the reason for delayed fracture of a titanium implant. PMID:12033593

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

2002-06-01

184

New device to treat chronic subdural hematoma--hollow screw.  

PubMed

Different surgical approaches exist for the treatment of chronic subdural hematoma. None of these approaches is superior to the other, so a minimal-invasive device (a hollow screw) was developed. The system consists of a stable hollow screw of surgical steel with a perforated tip, a hand-drill, screwdriver with guide, and collection bag. To place the screw in the skull local anesthesia is necessary followed by stab incision and percutaneous trephination. The screw is then placed in the bone and the guide removed. After spontaneous drainage and irrigation, a closed drainage system with a collection bag is connected with the screw. First results with the new technology are promising, with a high rate of completely treated patients and a low rate of complications. Two of 86 patients had a local skin infection after implantation of the screw, and in 22 patients the procedure was repeated due to one or more cases of recurrent or residual hematoma. No neurological deterioration was caused by the screw or the surgical approach. The advantages of this new system are: quick and simple procedure, minimal invasive, excellent function, inexpensive and reusable. PMID:10048060

Emonds, N; Hassler, W E

1999-01-01

185

Formal Methods in Development and Testing of Safety-Critical Systems: Railway Interlocking System  

Microsoft Academic Search

The contribution addresses the application of formal methods in functional specification, design and verification of real-time software systems in safety-critical applications. We present basic principles of software verification methods directed towards automatic proof of safety properties against the model of the system. Verification of the railway interlocking system developed by the AZD Prague Ltd. is presented. We discuss advantages and

Stepan Klapka

186

Interlock Schemes for Micropiplines: Application to a Self-Timed Rebound Sorter  

Microsoft Academic Search

Event controlled pipelines (micropipelines) have several advantages over clocked pipelines as they offer modularity and speed independence. The concept of micropipelines can be easily applied to any linear pipeline. In practice, most pipelines include feedback loops and, therefore, are not as easy to control as linear pipelines. A novel interlocking scheme to solve the control flow problem is proposed. As

Sankaran Karthik; Indira De Souza; Joseph T. Rahmeh; Jacob A. Abraham

1991-01-01

187

Periodic auto-active gels with topologically "polyrotaxane-interlocked" structures.  

PubMed

"Polyrotaxane-interlocked" gels which exhibit periodic swelling/deswelling oscillations without "on/off" switching of external stimuli are presented. The mechanical oscillation is driven by the redox oscillation in the BZ reaction and enhanced by the unique topological structure. PMID:24800737

Zhou, Hongwei; Wang, Yaru; Zheng, Zhaohui; Ding, Xiaobin; Peng, Yuxing

2014-06-18

188

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

SciTech Connect

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 {approx} 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.

Kane, Sanjeev R.; Garg, Chander Kant; Nandedkar, R. V. [Synchrotron Utilization and Material Research Division, Raja Ramanna Centre for Advanced Technology, Indore-452013 (India)

2007-01-19

189

Internal Iliac Artery Embolization during an Endovascular Aneurysm Repair with Detachable Interlock Microcoils  

PubMed Central

Objective The purpose of this study was to evaluate the effectiveness of detachable interlock microcoils for an embolization of the internal iliac artery during an endovascular aneurysm repair (EVAR). Materials and Methods A retrospective review was conducted on 40 patients with aortic aneurysms, who had undergone an EVAR between January 2010 and March 2012. Among them, 16 patients were referred for embolization of the internal iliac artery for the prevention of type II endoleaks. Among 16 patients, 13 patients underwent embolization using detachable interlock microcoils during an EVAR. Computed tomographic angiographies and clinical examinations were performed during the follow-up period. Technical success, clinical outcome, and complications were reviewed. Results Internal iliac artery embolizations using detachable interlock microcoils were technically successful in all 13 patients, with no occurrence of procedure-related complications. Follow-up imaging was accomplished in the 13 cases. In all cases, type II endoleak was not observed with computed tomographic angiography during the median follow-up of 3 months (range, 1-27 months) and the median clinical follow-up of 12 months (range, 1-27 months). Two of 13 (15%) patients had symptoms of buttock pain, and one patient died due to underlying stomach cancer. No significant clinical symptoms such as bowel ischemia were observed. Conclusion Internal iliac artery embolization during an EVAR using detachable interlock microcoils to prevent type II endoleaks appears safe and effective, although this should be further proven in a larger population.

Kim, Woo Chul; Hong, Kee Chun; Kim, Jang Yong; Cho, Soon Gu; Park, Jae Young

2014-01-01

190

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

NASA Astrophysics Data System (ADS)

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.

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

2007-01-01

191

Novel physically loaded and interlocked electrode developed for ionic polymer-metal composites (IPMCs)  

Microsoft Academic Search

Described is a novel fabrication process of manufacturing ionic polymeric metal composites (IPMC's) biomimetic sensors, actuators and artificial muscles equipped with physically loaded and interlocked (PLI) electrodes. The underlying principle of processing this novel PLI-IPMC's is to first physically load a conductive primary powder into the ionic polymer network forming a dispersed particulate layer. This primary layer functions as a

Mohsen Shahinpoor; Kwang J. Kim

2001-01-01

192

Intersection of screw dislocations in fcc crystals during torsional deformation  

NASA Astrophysics Data System (ADS)

Dislocation reactions, including dislocation intersections during various processes in crystals, play an important and often crucial role. This is most pronounced during plastic deformation of crystalline solids, which attracts particular interest from researchers. Intersection of screw dislocations in fcc crystals during their deformation by uniaxial tension and compression was studied by A. Cottrell [1]. It was shown that the intersection of similar screw dislocations moving toward each other results in the formation of interstitial thresholds on them; in the case of intersection of opposite screw dislocations, vacancy thresholds are formed on them.

Myshlyaev, M. M.

2012-03-01

193

Noninvasive method for retrieval of broken dental implant abutment screw  

PubMed Central

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

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

2014-01-01

194

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

PubMed Central

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

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

2014-01-01

195

Comparison of Cotrel-Dubousset pedicle screws and hooks in the treatment of idiopathic scoliosis  

Microsoft Academic Search

Eighty-two patients with idiopathic scoliosis were treated by Cotrel-Dubousset instrumentation between 1987 and 1991. Twenty were treated with hooks only, 47 with screws and hooks, and 15 with screws only. The methods were compared and the findings showed that screw fixation can be used in the thoracic spine without neurological complications. The screws provided immediate stability with rigid fixation, together

S. I. Suk; C. K. Lee; H. J. Min; K. H. Cho; J. H. Oh

1994-01-01

196

Pathological study of distal mesorectal cancer spread to determine a proper distal resection margin  

PubMed Central

AIM: Local recurrence after curative surgical resection for rectal cancer remains a major problem. Several studies have shown that incomplete removal of cancer deposits in the distal mesorectum contributes a great share to this dismal result. Clinicopathologic examination of distal mesorectum in lower rectal cancer was performed in the present study to assess the incidence and extent of distal mesorectal spread and to determine an optimal distal resection margin in sphincter-saving procedure. METHODS: We prospectively examined specimens from 45 patients with lower rectal cancer who underwent curative surgery. Large-mount sections were performed to microscopically observe the distal mesorectal spread and to measure the extent of distal spread. Tissue shrinkage ratio was also considered. Patients with involvement in the distal mesorectum were compared with those without involvement with regard to clinicopathologic features. RESULTS: Mesorectal cancer spread was observed in 21 patients (46.7%), 8 of them (17.8%) had distal mesorectal spread. Overall, distal intramural and/or mesorectal spreads were observed in 10 patients (22.2%) and the maximum extent of distal spread in situ was 12 mm and 36 mm respectively. Eight patients with distal mesorectal spread showed a significantly higher rate of lymph node metastasis compared with the other 37 patients without distal mesorectal spread (P = 0.043). CONCLUSION: Distal mesorectal spread invariably occurs in advanced rectal cancer and has a significant relationship with lymph node metastasis. Distal resection margin of 1.5 cm for the rectal wall and 4 cm for the distal mesorectum is proper to those patients who are arranged to receive operation with a curative sphincter-saving procedure for lower rectal cancer. PMID:15637735

Zhao, Gao-Ping; Zhou, Zong-Guang; Lei, Wen-Zhang; Yu, Yong-Yang; Wang, Cun; Wang, Zhao; Zheng, Xue-Lian; Wang, Rong

2005-01-01

197

Screw dislocation driven growth of nanomaterials.  

PubMed

Nanoscience and nanotechnology impact our lives in many ways, from electronic and photonic devices to biosensors. They also hold the promise of tackling the renewable energy challenges facing us. However, one limiting scientific challenge is the effective and efficient bottom-up synthesis of nanomaterials. We can approach this core challenge in nanoscience and nanotechnology from two perspectives: (a) how to controllably grow high-quality nanomaterials with desired dimensions, morphologies, and material compositions and (b) how to produce them in a large quantity at reasonable cost. Because many chemical and physical properties of nanomaterials are size- and shape-dependent, rational syntheses of nanomaterials to achieve desirable dimensionalities and morphologies are essential to exploit their utilities. In this Account, we show that the dislocation-driven growth mechanism, where screw dislocation defects provide self-perpetuating growth steps to enable the anisotropic growth of various nanomaterials at low supersaturation, can be a powerful and versatile synthetic method for a wide variety of nanomaterials. Despite significant progress in the last two decades, nanomaterial synthesis has often remained an "art", and except for a few well-studied model systems, the growth mechanisms of many anisotropic nanostructures remain poorly understood. We strive to go beyond the empirical science ("cook-and-look") and adopt a fundamental and mechanistic perspective to the anisotropic growth of nanomaterials by first understanding the kinetics of the crystal growth process. Since most functional nanomaterials are in single-crystal form, insights from the classical crystal growth theories are crucial. We pay attention to how screw dislocations impact the growth kinetics along different crystallographic directions and how the strain energy of defected crystals influences their equilibrium shapes. Furthermore, such inquiries are supported by detailed structural investigation to identify the evidence of dislocations. The dislocation-driven growth mechanism not only can unify the various explanations behind a wide variety of exotic nanoscale morphologies but also allows the rational design of catalyst-free solution-phase syntheses that could enable the scalable and low cost production of nanomaterials necessary for large scale applications, such as solar and thermoelectric energy conversions, energy storage, and nanocomposites. In this Account, we discuss the fundamental theories of the screw dislocation driven growth of various nanostructures including one-dimensional nanowires and nanotubes, two-dimensional nanoplates, and three-dimensional hierarchical tree-like nanostructures. We then introduce the transmission electron microscopy (TEM) techniques to structurally characterize the dislocation-driven nanomaterials for future searching and identifying purposes. We summarize the guidelines for rationally designing the dislocation-driven growth and discuss specific examples to illustrate how to implement the guidelines. By highlighting our recent discoveries in the last five years, we show that dislocation growth is a general and versatile mechanism that can be used to grow a variety of nanomaterials via distinct reaction chemistry and synthetic methods. These discoveries are complemented by selected examples of anisotropic crystal growth from other researchers. The fundamental investigation and development of dislocation-driven growth of nanomaterials will create a new dimension to the rational design and synthesis of increasingly complex nanomaterials. PMID:23738750

Meng, Fei; Morin, Stephen A; Forticaux, Audrey; Jin, Song

2013-07-16

198

Effects of ignition interlock license restrictions on drivers with multiple alcohol offenses: a randomized trial in Maryland.  

PubMed Central

OBJECTIVES: This investigation sought to test the effectiveness of a statewide ignition interlock license restriction program for drivers with multiple alcohol-related traffic offenses. METHODS: A total of 1387 multiple offenders eligible for license reinstatement were randomly assigned to participate in an ignition interlock program (experimental group) or in the conventional postlicensing treatment program (control group). The arrest rates of these 2 groups for alcohol traffic offenses were compared for 1 year during the ignition interlock license restriction program and for 1 year after unrestricted driving privileges were returned. RESULTS: Participation in the interlock program reduced offenders' risk of committing an alcohol traffic violation within the first year by about 65%. The alcohol traffic violation rate during the first year was significantly less for participants in the interlock program (2.4%) than for those in the control group (6.7%). However, there was no statistically significant difference between these groups in the second year, after the interlock license restriction was lifted. CONCLUSIONS: Ignition interlock license restriction programs are effective at reducing recidivism among drivers with multiple alcohol offenses, at least while the restriction is in effect. PMID:10553391

Beck, K H; Rauch, W J; Baker, E A; Williams, A F

1999-01-01

199

21. NBS SUIT LAB. THREE GLOVES, HELMET, AND SCREW DRIVER ...  

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

21. NBS SUIT LAB. THREE GLOVES, HELMET, AND SCREW DRIVER TORQUE WRENCH FOR ASSEMBLY AND REPAIR OF BOTH. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

200

Distal clavicle fracture as a complication of arthroscopic distal clavicle resection.  

PubMed

Arthroscopic resection of the distal clavicle has been advocated as a surgical treatment option for acromioclavicular (AC) joint pathology. To our knowledge, iatrogenic fracture of the distal clavicle during distal clavicle resection has never been reported. This report describes distal clavicle fracture as a complication of misidentification of the AC joint and subsequent aggressive burring of the distal clavicle during shoulder arthroscopy. This case is further complicated by the development of symptomatic delayed union and adhesive capsulitis. Ultimately, a revision distal clavicle resection was performed, underscoring the fact that special care must be taken to properly identify the AC joint and rule out pre-existing distal clavicle stress fracture or osteolysis before performing the arthroscopic Mumford procedure. PMID:19664514

Ghodadra, Neil; Lee, Gregory H; Kung, Peter; Busfield, Benjamin T; Kharazzi, F Daniel

2009-08-01

201

Effectiveness of ignition interlocks for preventing alcohol-impaired driving and alcohol-related crashes: a Community Guide systematic review.  

PubMed

A systematic review of the literature to assess the effectiveness of ignition interlocks for reducing alcohol-impaired driving and alcohol-related crashes was conducted for the Guide to Community Preventive Services (Community Guide). Because one of the primary research issues of interest--the degree to which the installation of interlocks in offenders' vehicles reduces alcohol-impaired driving in comparison to alternative sanctions (primarily license suspension)--was addressed by a 2004 systematic review conducted for the Cochrane Collaboration, the current review incorporates that previous work and extends it to include more recent literature and crash outcomes. The body of evidence evaluated includes the 11 studies from the prior review, plus four more recent studies published through December 2007. The installation of ignition interlocks was associated consistently with large reductions in re-arrest rates for alcohol-impaired driving within both the earlier and later bodies of evidence. Following removal of interlocks, re-arrest rates reverted to levels similar to those for comparison groups. The limited available evidence from three studies that evaluated crash rates suggests that alcohol-related crashes decrease while interlocks are installed in vehicles. According to Community Guide rules of evidence, these findings provide strong evidence that interlocks, while they are in use in offenders' vehicles, are effective in reducing re-arrest rates. However, the potential for interlock programs to reduce alcohol-related crashes is currently limited by the small proportion of offenders who participate in the programs and the lack of a persistent beneficial effect once the interlock is removed. Suggestions for facilitating more widespread and sustained use of ignition interlocks are provided. PMID:21335270

Elder, Randy W; Voas, Robert; Beirness, Doug; Shults, Ruth A; Sleet, David A; Nichols, James L; Compton, Richard

2011-03-01

202

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

PubMed Central

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

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

2014-01-01

203

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

E-print Network

SCREW TYPE STEAM COMPRESSORS FOR MECHANICAL VAPOR RECOMPRESSION (MVR) SYSTEMS K. KAWAMURA AND THOMAS-L. APALOO MYCOM CORPORATION, LOS ANGELES, CALIFORNIA MATSUDA, MAYEKAWA MFG. CO., TOKYO, JAPAN ABSTRACT In processes of evaporation...SCREW TYPE STEAM COMPRESSORS FOR MECHANICAL VAPOR RECOMPRESSION (MVR) SYSTEMS K. KAWAMURA AND THOMAS-L. APALOO MYCOM CORPORATION, LOS ANGELES, CALIFORNIA MATSUDA, MAYEKAWA MFG. CO., TOKYO, JAPAN ABSTRACT In processes of evaporation...

Kawamura, K.; Apaloo, Thomas-L.

204

Fixation of mandibular fractures with biodegradable plates and screws  

Microsoft Academic Search

Objective. Little data exist regarding the use of biodegradable plates and screws for the internal fixation of human mandibular fractures. The purpose of this study was to evaluate the stability of biodegradable, self-reinforced poly-L-lactide plates and screws for the internal fixation of fractures of the human mandible. Study Design. Twenty-two individuals (14 male, 8 female; average age, 26.3 years) with

Kaan C. Yerit; Georg Enislidis; Christian Schopper; Dritan Turhani; Felix Wanschitz; Arne Wagner; Franz Watzinger; Rolf Ewers

2002-01-01

205

Segmental pedicle screw instrumentation in idiopathic thoracolumbar and lumbar scoliosis  

Microsoft Academic Search

The role of posterior correction and fusion in thoracolumbar and lumbar scoliosis as well as pedicle screw instrumentation\\u000a in scoliosis surgery are matters of debate. Our hypothesis was that in lumbar and thoracolumbar scoliosis, segmental pedicle\\u000a screw instrumentation is safe and enables a good frontal and sagittal plane correction with a fusion length comparable to\\u000a anterior instrumentation. In a prospective

H. Halm; T. Niemeyer; T. Link; U. Liljenqvist

2000-01-01

206

Helical Screw Expander Evaluation Project. Final report  

SciTech Connect

A functional 1-MW geothermal electric power plant that featured a helical screw expander was produced and then tested in Utah in 1978 to 1979 with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing operation on two-phase geothermal fluids. The Project also produced a computer-equipped data system, an instrumentation and control van, and a 1000-kW variable load bank, all integrated into a test array designed for operation at a variety of remote test sites. Additional testing was performed in Mexico in 1980 under a cooperative test program using the same test array, and machine efficiency was measured at 62% maximum with the rotors partially coated with scale, compared with approximately 54% maximum in Utah with uncoated rotors, confirming the importance of scale deposits within the machine on performance. Data are presented for the Utah testing and for the noncondensing phases of the testing in Mexico. Test time logged was 437 hours during the Utah tests and 1101 hours during the Mexico tests.

McKay, R.

1982-03-01

207

Implant augmentation: adding bone cement to improve the treatment of osteoporotic distal femur fractures: a biomechanical study using human cadaver bones.  

PubMed

The increasing problems in the field of osteoporotic fracture fixation results in specialized implants as well as new operation methods, for example, implant augmentation with bone cement. The aim of this study was to determine the biomechanical impact of augmentation in the treatment of osteoporotic distal femur fractures.Seven pairs of osteoporotic fresh frozen distal femora were randomly assigned to either an augmented or nonaugmented group. In both groups, an Orthopaedic Trauma Association 33 A3 fractures was fixed using the locking compression plate distal femur and cannulated and perforated screws. In the augmented group, additionally, 1?mL of polymethylmethacrylate cement was injected through the screw. Prior to mechanical testing, bone mineral density (BMD) and local bone strength were determined. Mechanical testing was performed by cyclic axial loading (100?N to 750?N?+?0.05N/cycle) using a servo-hydraulic testing machine.As a result, the BMD as well as the axial stiffness did not significantly differ between the groups. The number of cycles to failure was significantly higher in the augmented group with the BMD as a significant covariate.In conclusion, cement augmentation can significantly improve implant anchorage in plating of osteoporotic distal femur fractures. PMID:25415673

Wähnert, Dirk; Hofmann-Fliri, Ladina; Richards, R Geoff; Gueorguiev, Boyko; Raschke, Michael J; Windolf, Markus

2014-11-01

208

Unilateral Molar Distalization: A Nonextraction Therapy  

PubMed Central

In the recent years, nonextraction treatment approaches and noncompliance therapies have become more popular in the correction of space discrepancies. One of the conventional approaches for space gaining in the arches without patient compliance is done by using certain extra oral appliances or intraoral appliance. The greatest advantage of certain appliances like fixed functional and molar distalization appliances is that they minimize the dependence on patient cooperation. Molar distalization appliances like pendulum appliance which distalizes the molar rapidly without the need of head gear can be used in patients as a unilateral space gaining procedure due to buccal segment crowding. PMID:23320203

Prasad, M. Bhanu; Sreevalli, S.

2012-01-01

209

Screw fixation of the syndesmosis: a cadaver model comparing stainless steel and titanium screws and three and four cortical fixation  

Microsoft Academic Search

We assessed syndesmotic set screw strength and fixation capacity during cyclical testing in a cadaver model simulating protected weight bearing. Sixteen fresh frozen legs with artificial syndesmotic injuries and a syndesmotic set screw made of stainless steel or titanium, inserted through three or four cortices, were axially loaded with 800N for 225,000 cycles in a materials testing machine. The 225,000

Annechien Beumer; Martin M. Campo; Ruud Niesing; Judd Day; Gert-Jan Kleinrensink; Bart A. Swierstra

2005-01-01

210

An analytical investigation of high-temperature heat pump system with screw compressor and screw expander for power recovery  

Microsoft Academic Search

An analytical investigation of a high-temperature heat pump system was developed to estimate the thermal cycle and to assess the thermal fluids for their high-temperature delivery (up to 180°C) capacities without decomposition or the use of lubricant mechanisms. Then, a screw-type compressor was applied in the above conditions. Furthermore, a screw expander was also used as a replacement for the

I. Tamura; H. Taniguchi; H. Sasaki; R. Yoshida; I. Sekiguchi; M. Yokogawa

1997-01-01

211

Instability of the distal radioulnar joint.  

PubMed

The distal radioulnar joint is a complex structure necessary for forearm motion and force transmission across the wrist. Anatomic and biomechanical advances have revealed broad contributions to distal radioulnar joint stability and refined our understanding of the forces acting across it. Instability often co-occurs with other modes of pathology, such as arthrosis or malunion; and appropriate diagnosis and treatment require a comprehensive understanding of all contributing factors. Distal radioulnar joint instability can be broadly categorized as primary, post-traumatic or post-surgical. Treatment strategies include percutaneous, arthroscopic, soft-tissue, osteotomy and arthroplasty techniques. The purpose of this article is to review distal radioulnar joint instability and its management. PMID:24619248

Zimmerman, R M; Jupiter, J B

2014-09-01

212

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

SciTech Connect

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.

Larsen, R

2009-10-17

213

49 CFR 1242.17 - Signals and interlockers (accounts XX-17-19 and XX-18-19).  

Code of Federal Regulations, 2010 CFR

...Transportation 9 2010-10-01 2010-10-01 false Signals and interlockers (accounts XX-17-19 and XX-18-19). 1242.17 Section 1242.17 Transportation Other Regulations Relating to Transportation (Continued) SURFACE...

2010-10-01

214

49 CFR 1242.17 - Signals and interlockers (accounts XX-17-19 and XX-18-19).  

Code of Federal Regulations, 2011 CFR

...Transportation 9 2011-10-01 2011-10-01 false Signals and interlockers (accounts XX-17-19 and XX-18-19). 1242.17 Section 1242.17 Transportation Other Regulations Relating to Transportation (Continued) SURFACE...

2011-10-01

215

49 CFR 1242.17 - Signals and interlockers (accounts XX-17-19 and XX-18-19).  

Code of Federal Regulations, 2012 CFR

...Transportation 9 2012-10-01 2012-10-01 false Signals and interlockers (accounts XX-17-19 and XX-18-19). 1242.17 Section 1242.17 Transportation Other Regulations Relating to Transportation (Continued) SURFACE...

2012-10-01

216

49 CFR 1242.17 - Signals and interlockers (accounts XX-17-19 and XX-18-19).  

Code of Federal Regulations, 2013 CFR

...Transportation 9 2013-10-01 2013-10-01 false Signals and interlockers (accounts XX-17-19 and XX-18-19). 1242.17 Section 1242.17 Transportation Other Regulations Relating to Transportation (Continued) SURFACE...

2013-10-01

217

Effects of dynamization after interlocking tibial nailing: an experimental study in dogs.  

PubMed

Dynamization of statically locked tibial nails was studied in a canine model. Reamed static interlocking nails were inserted in 16 canine tibiae with unstable osteotomies. At 8 weeks, half were dynamized. At 20 weeks, the tibiae were harvested and studied radiographically, biomechanically, and histologically. Apparent clinical union was present in all tibiae. Complete radiographic bony union was achieved in 13 of 16, with residual radiolucent lines in two tibiae in the static and one in the dynamic group. Biomechanically, dynamization improved stiffness at the fracture site. Histological patterns were similar, but there were trends toward a denser trabecular callus pattern in the dynamized group. The results of this animal study indicate that although dynamization may have a beneficial effect on the quality of early bony healing, static interlocking does not decrease the rate of bony union. PMID:2231132

Georgiadis, G M; Minster, G J; Moed, B R

1990-01-01

218

Percutaneous ORIF of Periarticular Distal Tibia Fractures  

Microsoft Academic Search

\\u000a Periarticular fractures of the distal tibia remain among the more challenging of fractures for the orthopedic surgeon. Traditional\\u000a methods of treatment have included functional bracing, external fixation with or without limited internal fixation (hybrid\\u000a fixation), intramedullary nailing, and formal open reduction internal fixation (ORIF). Cadaveric studies have previously described\\u000a the somewhat tenuous vascular supply to the distal metaphysis, which, combined

Michael P. Clare; Roy W. Sanders

219

Prediction of Deformity Correction by Pedicle Screw Instrumentation in Thoracolumbar Scoliosis Surgery  

NASA Astrophysics Data System (ADS)

In segmental pedicle screw instrumentation, the relationship between the combinations of pedicle screw placements and the degree of deformity correction was investigated with a three-dimensional rigid body and spring model. The virtual thoracolumbar scoliosis (Cobb’s angle of 47 deg.) was corrected using six different combinations of pedicle-screw placements. As a result, better correction in the axial rotation was obtained with the pedicle screws placed at or close to the apical vertebra than with the screws placed close to the end vertebrae, while the correction in the frontal plane was better with the screws close to the end vertebrae than with those close to the apical vertebra. Additionally, two screws placed in the convex side above and below the apical vertebra provided better correction than two screws placed in the concave side. Effective deformity corrections of scoliosis were obtained with the proper combinations of pedicle screw placements.

Kiriyama, Yoshimori; Yamazaki, Nobutoshi; Nagura, Takeo; Matsumoto, Morio; Chiba, Kazuhiro; Toyama, Yoshiaki

220

New structural insights into mechanically interlocked polymers revealed by ion mobility mass spectrometry.  

PubMed

Mechanically interlocked polymers can possess significant additional physical properties, in comparison to those associated with their constituent parts. Their unique properties make them attractive for a range of potential applications, such as as biomaterials and molecular machines. Their efficient and reproducible synthesis is therefore of much interest. Both their synthesis and subsequent characterization are intriguing yet demanding. The properties of mechanically interlocked polymeric systems depend not only on the properties of their individual components but also on the topology of the subsequent product. Here traveling wave ion mobility mass spectrometry has been used to investigate the structural properties of a polyrotaxane system. Ion mobility studies reveal that this system remains linear in form with increase in size. Both ion mobility studies and tandem mass spectrometry studies indicate that the macrocycle preferentially remains associated with the ammonium moiety of the polymeric repeat unit and is impeded from moving freely along the axle. This is consistent with NMR observations of the average structure. Analysis of mechanically interlocked polymers by ion mobility mass spectrometry provides additional structural insights into these systems relating to dynamics, heterogeneity, and topology. This molecule-specific information is vital in order to understand the origin of a system's functional properties. PMID:22616687

Scarff, Charlotte A; Snelling, Jonathon R; Knust, Matthias M; Wilkins, Charles L; Scrivens, James H

2012-06-01

221

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

SciTech Connect

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

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

1999-11-01

222

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

PubMed Central

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

Edling, Christofer

2010-01-01

223

Pedicle screw piercer with warning device - A technique to increase accuracy of pedicle screw placement  

PubMed Central

Background: Pedicle screw fixation has achieved significant popularity amongst spinal surgeons for both single and multilevel spinal fusion. Suboptimal placements of pedicle screws may lead to neurological and vascular complications. There have been many advances in techniques available for navigating through the pedicle; however, these techniques are not without drawbacks. The purpose of this study was to investigate the efficacy and feasibility of the pedicle piercer with warning device. Materials and Methods: Eight normal adult thoracolumbar specimens from cadavers consisting of 80 vertebras (T8–L5) were selected and randomly allocated into four groups. Each group contained 20 vertebra. Group 1 was tested for maximum pressure of the piercer within the vertebrae (F1). Group 2 was tested for maximum pressure of the warning piercer penetrating front cortex of the vertebral body (F2). Group 3 was tested for the maximum pressure of piercer penetrating vertebral body endplate (F3) and pedicle notch (F41, F42). Group 4 was tested for maximum pressure of the piercer penetrating the vertebral lateral cortex (F6), the medial and lateral cortex of pedicle (F51, F52). In the second experiment of this study, 4 normal adult specimens consisting of 40 vertebra and 80 pedicles were used for testing the alarm effects of pedicle piercer. The following indicators were adopted for the tests including true positive/negative, false positive/negative, sensitivity, specificity, availability, Youden index, and diagnostic efficiency. SPSS 16.0 was used for statistical analysis. Results: There were statistically significant differences between F1, and F2, F3, F41, F42, F51, F52 respectively (P < 0.05). F1 = 8.970 ± 0.2698, F3 = 13.055 ± 0.6718. We found that the threshold value of piercer warning was from 9.6 to 12.3 Kgf. Sensitivity was 92.31%, specificity was 95.12%, usability was 87.45%, Youden index was 87.43% and diagnostic efficiency was 92.5% respectively. Conclusion: Warning piercer is a safe, simple, sensitive device for detecting pedicle breach during regular pedicle screw placement surgery.

Bin, Lin; Yong, He; Yang, Xu; Bi, Zhang; Mo, Sha; Zhi-Min, Guo

2014-01-01

224

Endovascular aortic injury repair after thoracic pedicle screw placement.  

PubMed

Our objective was to describe the management and prevention of thoracic aortic injuries caused by a malposition of pedicle screws in corrective surgery of major spine deformities. Positioning pedicle screws in thoracic vertebras by posterior approach exposes to the risk of injury of the elements placed ahead of the thoracic spine, as the descending thoracic aorta. This complication can result in a cataclysmic bleeding, needing urgent vascular care, but it can also be totally asymptomatic, resulting in the long run in a pseudoaneurysm, justifying the systematic removal of the hardware. We report the case of a 76-year-old woman who underwent spinal correction surgery for thoraco-lumbar degenerative kypho-scoliosis. Immediately after the surgery, a thoracic aortic injury caused by the left T7 pedicle screw was diagnosed. The patient underwent a two-step surgery. The first step was realized by vascular surgeons and aimed to secure the aortic wall by short endovascular aortic grafting. During the second step, spine surgeons removed the responsible screw by posterior approach. The patient was discharged in a rehabilitation center 7 days after the second surgery. When such a complication occurs, a co-management by vascular and spine surgeons is necessary to avoid major complications. Endovascular management of this kind of vascular injuries permits to avoid an open surgery that have a great rate of morbi-mortality in frail patients. Nowadays, technologies exist to prevent this kind of event and may improve the security when positioning pedicle screws. PMID:25023930

Pesenti, S; Bartoli, M A; Blondel, B; Peltier, E; Adetchessi, T; Fuentes, S

2014-09-01

225

Screw dislocations in GaN grown by different methods  

SciTech Connect

A study of screw dislocations in Hydride-Vapor-Phase-Epitaxy (HVPE) template and Molecular-Beam-Epitaxy (MBE) over-layers was performed using Transmission Electron Microscopy (TEM) in plan-view and in cross-section. It was observed that screw dislocations in the HVPE layers were decorated by small voids arranged along the screw axis. However, no voids were observed along screw dislocations in MBE overlayers. This was true both for MBE samples grown under Ga-lean and Ga-rich conditions. Dislocation core structures have been studied in these samples in the plan-view configuration. These experiments were supported by image simulation using the most recent models. A direct reconstruction of the phase and amplitude of the scattered electron wave from a focal series of high-resolution images was applied. It was shown that the core structures of screw dislocations in the studied materials were filled. The filed dislocation cores in an MBE samples were stoichiometric. However, in HVPE materials, single atomic columns show substantial differences in intensities and might indicate the possibility of higher Ga concentration in the core than in the matrix. A much lower intensity of the atomic column at the tip of the void was observed. This might suggest presence of lighter elements, such as oxygen, responsible for their formation.

Liliental-Weber, Z.; Zakharov, D.; Jasinski, J.; O'Keefe, M.A.; Morkoc, H.

2003-05-27

226

Ball screw preload loss detection using ball pass frequency  

NASA Astrophysics Data System (ADS)

A technique of determining the onset of preload loss in a ball screw feed drive system via monitoring the change of ball pass frequency is proposed. The ball pass frequency of a ball screw with preload is smaller than that of ball screw without preload due to friction caused by the preload. Results from both simulations and experiments show that the ball pass frequency can be detected using the method of Angular Velocity Vold-Kalman Filtering Order Tracking (AV VKF-OT). And AV VKF-OT provides a much better performance as compared to the traditional order tracking in terms of resolution and accuracy. Tests were conducted on ball screw feed drive systems with different preloads for the performance assessment of the ball pass frequency detection. Results show that the preload loss increases the ball pass frequency and also induces the side band around the ball pass frequency, which provides promising criteria in detecting the onset of preload loss of ball screws.

Tsai, P. C.; Cheng, C. C.; Hwang, Y. C.

2014-10-01

227

[Observations on before and after employ of screw of implant denture with SEM].  

PubMed

The loss of screw is one of the clinic complication in MDIC implant denture cases. The purpose of this study is to find the cause of loss of screw. The authors has studied MDIC implant denture with SEM before and after employ of the screw and found that the causes of screw loss were crevice corrosion and friction pressure. Crevice corrosion may promote the loss of screw. Base the above condition, it is necessary to select Ti-alloy screw and associat with anticorrosive measure in MDIC implant denture construction. PMID:10677963

Song, Y; Xu, J; Ma, X

1997-03-01

228

Femoral neck fracture after removal of the standard gamma interlocking nail: a cadaveric study to determine factors influencing the biomechanical properties of the proximal femur.  

PubMed

We retrospectively analyzed 1334 patients who were implanted standard gamma interlocking nails (SGN) to stabilize trochanteric femoral fractures over the years 1992-1998. Reoperation to remove the nails was performed in 37 patients, in 9 of them purely because of pain. Three out of these 9 patients with removed SGN suffered femoral neck fractures in the early postoperative course after having been mobilized to full weight-bearing capacity. This complication was not observed with other implant systems and, considering the notoriously high complication rate of femoral neck fractures, severely reduces the value of the SGN concept per se. These findings in combination with other known shortcomings of SGNs prompted us to conduct an experimental study on the fracture force of excavated femurs addressing the hypothesis that the specific design of the SGN is responsible for the occurrence of fatigue fractures of the femoral neck. Eighteen matched pairs of fresh human cadaveric proximal femurs, which were treated by insertion and removal of (i) SGNs or (ii) dynamic hip screws (DHS) or (iii) by excavation in the absence of an implant, were subjected to incremental loading cycles and compared to the untreated contralateral femurs. Overall, the fracture force was found to be significantly lower among the treated than among the untreated bones. However, the fracture force required after removal of the DHS system was still significantly higher than for SGN or excavation alone. In this way, our findings demonstrate that removing relatively big implants such as SGN can cause serious complications such as femoral neck fractures. We therefore recommend to leave this type of device in place even after fracture healing except in cases of deep and chronic infection. PMID:11716853

Kukla, C; Pichl, W; Prokesch, R; Jacyniak, W; Heinze, G; Gatterer, R; Heinz, T

2001-12-01

229

Mild coal gasification screw pyrolyzer development and design  

SciTech Connect

Our objective is to produce information and design recommendations needed for the development of an efficient continuous process for the mild gasification of caking bituminous coals. We have focused on the development of an externally heated pyrolyzer in which the sticky, reacting coal is conveyed by one or more screws. We have taken a multifaceted approach to forwarding the development of the externally-heated screw pyrolyzer. Small scale process experiments on a 38-mm single screw pyrolyzer have been a major part of our effort. Engineering analyses aimed at producing design and scaleup equations have also been important. Process design recommendations follow from these. We critically review our experimental data and experience, and information from the literature and equipment manufactures for the purpose of making qualitative recommendations for improving practical pyrolyzer design and operation. Benchscale experiments are used to supply needed data and test some preliminary concepts. 6 refs., 4 figs., 1 tab.

Camp, D.W.

1990-08-01

230

[Dental reconstruction with non-precious metal screws and posts].  

PubMed

A short review of the current methods for restoring destroyed dental crowns by mechanical retentive elements. The causes leading to failure in such restorations are mentioned in a short review of literature. Main causes are corrosive changes in posts and screws anchored in root canals. This is why a special chapter deals with the problem of corrosion. A systematic enumeration of various corrosions in posts and screws is illustrated by a choice of clinical and radiological illustrations. The author's own metallurgical analytic investigations of the posts and screws available commercially allow to divide them into 4 typical nonprecious metal groups: Inox steel, cromium nickel steel, cromium nickel molybdene steel and brass alloys. The reasons for resistance to corrosion lie in the different metallographic structures and processing methods. Further investigations are finished and will be published later in this journal. PMID:392757

Wirz, J; Johner, M; Pohler, O

1979-11-01

231

SEM and fractography analysis of screw thread loosening in dental implants.  

PubMed

Biological and technical failures of implants have already been reported. Mechanical factors are certainly of importance in implant failures, even if their exact nature has not yet been established. The abutment screw fracture or loosening represents a rare, but quite unpleasant failure. The aim of the present research is an analysis and structural examination of screw thread or abutment loosening compared with screw threads or abutment without loosening. The loosening of screw threads was compared to screw thread without loosening of three different implant systems; Branemark (Nobel Biocare, Gothenburg, Sweden), T.B.R. implant systems (Benax, Ancona, Italy) and Restore (Lifecore Biomedical, Chaska, Minnesota, USA). In this study broken screws were excluded. A total of 16 screw thread loosenings were observed (Group I) (4 Branemark, 4 T.B.R and 5 Restore), 10 screw threads without loosening were removed (Group II), and 6 screw threads as received by the manufacturer (unused) (Group III) were used as control (2 Branemark, 2 T.B.R and 2 Restore). The loosened abutment screws were retrieved and analyzed under SEM. Many alterations and deformations were present in concavities and convexities of screw threads in group I. No macroscopic alterations or deformations were observed in groups II and III. A statistical difference of the presence of microcracks were observed between screw threads with an abutment loosening and screw threads without an abutment loosening. PMID:17897496

Scarano, A; Quaranta, M; Traini, T; Piattelli, M; Piattelli, A

2007-01-01

232

Failure of synthes anterior cervical fixation device by fracture of Morscher screws: a biomechanical study.  

PubMed

Anterior cervical fixation using the Synthes system has become increasingly popular. Two screw types for anchoring the plates include a "solid" titanium expansion screw and a plasma-sprayed fenestrated expansion screw that permits bony ingrowth. These screws were compared clinically and in the laboratory. In our first 20 cases using Synthes plates secured by Morscher fenestrated screws, 3 failures were observed, unilaterally in 1 patient and bilaterally in 2 others. In the unilateral screw failure, the contralateral screw was "solid" and did not fail. In the mechanical studies, screws were secured in the Synthes plate and embedded into methylmethacrylate and subjected to a sinusoidal bending moment to the mid-shaft of the screw. Load deflection data and cycles to failure were recorded. Fenestrated screws were found to demonstrate nearly twice as much deformation at failure and tolerated significantly fewer cycles to failure than did "solid" screws (p < 0.05). Because benefits of bony ingrowth into the screw are not well identified, the risks of fenestrated screw failure should preclude their routine use. PMID:8003828

Hollowell, J P; Reinartz, J; Pintar, F A; Morgese, V; Maiman, D J

1994-04-01

233

Comparative study on stress distribution around internal tapered connection implants according to fit of cement- and screw-retained prostheses  

PubMed Central

PURPOSE The aim of this study was to compare the passivity of implant superstructures by assessing the strain development around the internal tapered connection implants with strain gauges. MATERIALS AND METHODS A polyurethane resin block in which two implants were embedded served as a measurement model. Two groups of implant restorations utilized cement-retained design and internal surface of the first group was adjusted until premature contact between the restoration and the abutment completely disappeared. In the second group, only nodules detectable to the naked eye were removed. The third group employed screw-retained design and specimens were generated by computer-aided design/computer-aided manufacturing system (n=10). Four strain gauges were fixed on the measurement model mesially and distally to the implants. The strains developed in each strain gauge were recorded during fixation of specimens. To compare the difference among groups, repeated measures 2-factor analysis was performed at a level of significance of ?=.05. RESULTS The absolute strain values were measured to analyze the magnitude of strain. The mean absolute strain value ranged from 29.53 to 412.94 µm/m at the different strain gauge locations. According to the result of overall comparison, the cement-retained prosthesis groups exhibited significant difference. No significant difference was detected between milled screw-retained prostheses group and cement-retained prosthesis groups. CONCLUSION Within the limitations of the study, it was concluded that the cement-retained designs do not always exhibit lower levels of stress than screw-retained designs. The internal adjustment of a cement-retained implant restoration is essential to achieve passive fit. PMID:24049573

Lee, Mi-Young; Heo, Seong-Joo; Park, Eun-Jin

2013-01-01

234

Long-term results of cemented and screwed acetabular components.  

PubMed

The authors report their experience in the use of various types of acetabular components (cemented and screwed) in 253 hip prostheses with "Biodirect" femoral component and ceramic femoral head. A long-term follow-up of 148 hip prostheses (58.5% of the total) was carried out, 36 Müller type polyethylene and 61 Biolox ceramic acetabular components, and 51 screwed sockets of various models were used. From a clinical and radiographical standpoint, the ceramic acetabular component proved the most valid in the short and medium term, confirming the favourable biomechanical conditions which derive from ceramic/ceramic coupling. PMID:8567260

Agrifoglio, E; Federici, A; Sanguineti, F; Maxena, S; Giacchè, P

1993-01-01

235

Virtual estimates of fastening strength for pedicle screw implantation procedures  

NASA Astrophysics Data System (ADS)

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.

Linte, Cristian A.; Camp, Jon J.; Augustine, Kurt E.; Huddleston, Paul M.; Robb, Richard A.; Holmes, David R.

2014-03-01

236

[The biomechanics of screws, cerclage wire and cerclage cable].  

PubMed

In contrast to fracture fixation, when performing an osteotomy the surgeon is able to plan preoperatively. The resulting fixation and compression of the bone fragments are the most important points. A stable osteosynthesis should prevent dislocation of bone fragments and improve bone healing. Beside plates, cerclages can be used for tension band or diaphysis bone fixation. Moreover, cortical or cancellous screws can be used for osteotomy fixation. This work describes biomechanical principles for fixation after an osteotomy with cerclages and cortical or cancellous screws. It also summarizes the materials and geometries used, as well as their influence on the stability of the osteosynthesis. PMID:23615626

Schröder, C; Woiczinski, M; Utzschneider, S; Kraxenberger, M; Weber, P; Jansson, V

2013-05-01

237

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

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

238

Hybrid dynamic modeling of a high-speed ball-screw drive system  

Microsoft Academic Search

The longitudinal and torsional vibration of a lead-screw usually limits the closed-loop performance of a high-speed ball-screw drive system. It is difficult to accurately characterize the high frequency dynamics of the ball-screw drive system via a traditional lumped modeling method. This paper proposes a hybrid parameter modeling method. The model contains a distributed parameter model of the lead-screw with the

Yan Liu; Tong Zhao; Hui Zhang

2010-01-01

239

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

PubMed Central

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

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

2014-01-01

240

Distal ligament in human glans: a comparative study of penile architecture.  

PubMed

To elucidate the anatomic distal ligament of the human glans penis and associated clinical implications, we compared the structures of the glans penis and corpora cavernosa in dogs, rats, and humans. From May 2001 to March 2003, gross dissection, microscopic examinations, and stains for elastic fibers and collagen subtypes were made in the penises of 11 adult human male cadavers, 7 dogs, and 5 rats. A distal ligament in the human glans penis replaces the os penis that is present in dogs or rats, also termed the baculum, but retains collagen types I and III as common structural and interlocking components, respectively. The intercavernosal septum is complete, and intracavernosal pillars (ICPs) are abundant in dogs, absent in rats, and moderately developed in humans. A tunica with numerous elastic fibers exists to fulfill the requirements of erectile function in humans but not in dogs or rats, since it is essential for establishing tissue strength to serve as a buttress. We may conclude that in dogs and rats, the strong os penis is designed for ready intromission and is associated with a pair of well-developed nonelastic corpora to serve as a buttress for the os penis. These structures are necessary for the rigorous coitus observed in dogs. The less compliant corpus cavernosum is suitable for the flipping action observed in a mating male rat. These specific anatomic designs may provide explanations for the individual requirements for the specific physiologic functions that differ from species to species. Although there is no os in the human glans, a strong equivalent distal ligament is arranged centrally and acts as a supporting trunk for the glans penis. Without this important structure, the glans could be too weak to bear the buckling pressure generated during coitus and too limber to serve as a patent passage for ejaculation, and it could be too difficult to transmit the intracavernosal pressure surge along the entire penis during ejaculation. Given the common histologic nature of the distal ligament, which is associated with the tunica albuginea and serves a similar function as the os penis observed in the dog and the rat, one may ask whether the healing process of a tunica may take as long as that required in a bony structure. Further research is required to answer this question. PMID:16088040

Hsu, Geng-Long; Lin, Chung-Wu; Hsieh, Cheng-Hsing; Hsieh, Ju-Ton; Chen, Shyh-Chyan; Kuo, Tzong-Fu; Ling, Pei-Ying; Huang, Hsiu-Mei; Wang, Chii-Jye; Tseng, Guo-Fang

2005-01-01

241

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

Microsoft Academic Search

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

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

1998-01-01

242

Incorporation of prefabricated screw, pneumatic, and solenoid valves into microfluidic devices  

E-print Network

Incorporation of prefabricated screw, pneumatic, and solenoid valves into microfluidic devices S This paper describes a method for prefabricating screw, pneumatic, and solenoid valves and embedding them a technique for creating standardized, prefabricated valves of three types--screw valves, pneumatic valves

Prentiss, Mara

243

Piezoelectric actuators for screw-in cartridge valves  

Microsoft Academic Search

Research has been undertaken to explore the possibility of using smart materials for the actuation of screw-in cartridge valves. Four types were considered and a piezoelectric (PZT) stack was selected as the most appropriate actuator. The concept of a spool valve piloted by a PZT valve was chosen for investigation. A mathematical model of a hydraulic system with a spool

Xiaoping Ouyang; Derek Tilley; Patrick Keogh; Huayong Yang; Nigel Johnson; Chris Bowen; Peter Hopkins

2008-01-01

244

Sacroiliac screw fixation: A mini review of surgical technique  

PubMed Central

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

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

2014-01-01

245

Probabilistic model and experimental identification of screw-attachment in  

E-print Network

for the screw-attachment of large light partition wall between plasterboard (CPC) plate and metallic frame in Materials Characterisation Location: New Forest, ENGLAND Date: JUN 17-19, 2009, New Forest : United Kingdom element is a large light partition wall with plasterboard using metallic frame. The plasterboard

Paris-Sud XI, Université de

246

The Use of Small Titanium Screws for Orthodontic Anchorage  

Microsoft Academic Search

The use of conventional dental implants for orthodontic anchorage is limited by their large size. The purpose of this study was to quantify the histomorphometric properties of the bone-implant interface to analyze the use of small titanium screws as an orthodontic anchorage and to establish an adequate healing period. Overall, successful rigid osseous fixation was achieved by 97% of the

T. Deguchi; T. Takano-Yamamoto; R. Kanomi; J. K. Hartsfield; W. E. Roberts; L. P. Garetto

2003-01-01

247

Intelligent Operation Parameters Optimization for Screw Conveyor Based on PSO  

Microsoft Academic Search

Particle swarm optimization (PSO) is a population based stochastic optimization technique. As a result, PSO algorithm is widely used in mechanical engineering design field. Screw conveyors are used extensively in agriculture and processing industries for elevating and\\/or transporting bulk materials over short to medium distances. They are very effective for conveying dry particulate solids, giving good control over the throughput.

Jianghui Cai; Wenjun Meng

2010-01-01

248

Screw dislocation in a two-phase isotropic thin film  

NASA Astrophysics Data System (ADS)

By using the complex potential and conformal mapping techniques, the stress field of a straight screw dislocation lying parallel to the surface of a two-phase isotropic thin film of equal thickness in each phase and a welded interface is analyzed. The solution, when reduced to a single-phase thin film, is in agreement with that derived by Liebfried and Dietze using an infinite array of image dislocations. The presence of a second phase is found to increase the magnitude of the stress components for the screw dislocation except for ?xz near the interface where the effect is the reverse. The image force on the dislocation near the interface can be attractive or repulsive depending upon whether the dislocation is situated in the hard or soft phase. In the case where the dislocation is situated in the soft phase, the total image force tends to drive the screw dislocation to the surface. Furthermore, the screw dislocation is found to be unstable at the interface. The elastic solution for an interfacial dislocation becomes a special case.

Chu, S. N. G.

1982-04-01

249

A molecular "screw-clamp": accelerating click reactions in miniemulsions.  

PubMed

The interface as a "screw clamp": the copper-free 1,3-dipolar azide-alkyne cycloaddition at the interface of nanodroplets in miniemulsions was studied in detail by NMR spectroscopic methods. The reaction at the oil-water interface proved to exhibit higher rate constants, increased molecular weights and high regioregularity compared to the reaction in solution. PMID:25068922

Alexandrino, Evandro M; Buchold, Philipp; Wagner, Manfred; Fuchs, Adrian; Kreyes, Andreas; Weiss, Clemens K; Landfester, Katharina; Wurm, Frederik R

2014-09-18

250

Throttling means for geothermal streams. [helical screw expander  

Microsoft Academic Search

A helical screw expander for deriving energy from geothermally heated water is described. The expander includes a pair of helical rotors with helical structures fitted in an expansion chamber. The geothermally heated water is introduced into said chamber through a throttle port located at an end face of the expansion chamber, whereby precipitation which occurs as a consequence of reduction

Sprankle

1976-01-01

251

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

252

Positive identification facilitated by implanted metallic plate and screws.  

PubMed

Personal identification is an essential subject in forensic practice. With skeletonized remains, an anthropological examination is performed for personal identification. Here we describe the positive identification of skeletonized human remains from the serial numbers of implanted metallic plate and screws. PMID:19534396

Kinoshita, Hiroshi; Motomura, Hiroyuki; Kasuda, Shogo; Nishiguchi, Minori; Matsui, Kiyoshi; Takahashi, Motonori; Ouchi, Harumi; Minami, Takako; Yamamura, Takehiko; Otsu, Nao; Yoshida, Shie; Adachi, Nobuyuki; Ohta, Takehiko; Hishida, Shigeru

2009-04-01

253

Successful Transcatheter Embolization of Penetrating Aortic Ulcer Using Interlocking Detachable Coils  

SciTech Connect

A 54-year-old man with persistent chest pain was hospitalized for hypertension and DeBakey type IIIb aortic dissection. The false lumen of the dissection was almost completely thrombosed; however, a penetrating atherosclerotic ulcer (PAU) was observed 5 weeks later. At that time, we successfully embolized the PAU with a microcatheter and interlocking detachable coils (IDCs). The patient is well with no episodes of relapse in 20 months of follow-up. This case suggests the utility of the microcatheter and IDC system as an alternative to surgery.

Hama, Yukihiro; Kaji, Tatsumi; Iwasaki, Yoshie [Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042 (Japan); Hinokiyama, Kazuhiro; Shimizu, Masafumi [Department of Surgery II, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042 (Japan); Kusano, Shoichi [Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042 (Japan)

2000-09-15

254

Detection of trace cobalt ions in in vivo plant cells using a voltammetric interlocking system.  

PubMed

This experiment was conducted to establish a system for detecting trace cobalt ions in water and plant tissues using a voltammetric in vivo sensor. Cyclic and stripping voltammetry was devised from hand-made, macro-type implantable three-electrode systems. The results reached micro and nano working ranges at 100 sec accumulation time. The statistical detection limit (S/N) was attained at 6.0 ng L(-1). For the in vivo application, direct assay of cobalt ions was carried out in Eichhornia crassipes (EC) deep tissue in real time with a preconcentration time of 100 s. Interfaced techniques can be interlocked with other control systems. PMID:23508160

Ly, Suw Young; Shin, Myoung Ho; Lee, Chang Hyun; Lee, Jin Hui; Kim, Mi Sook; Ji, Sang Woo; Park, Dong Won

2013-01-01

255

Distally Based Dorsal Forearm Fasciosubcutaneous Flap  

Microsoft Academic Search

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 re- construct skin defects on the dorsum of the

Kwang Seog Kim

2004-01-01

256

Distal Xq duplication and functional Xq disomy  

Microsoft Academic Search

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

Damien Sanlaville; Caroline Schluth-Bolard; Catherine Turleau

2009-01-01

257

[The effect of an angle-stable plate-screw connection and various screw diameters on the stability of plate osteosynthesis. An FE model study].  

PubMed

In a finite element model of a human femur with an attached stainless steel six-hole plate exposed to a load equivalent to that set up by standing on one leg, pressures on the face of the screw holes, bending stresses in the screws, and axial bone stresses in the mid-plate transverse section were determined. The calculations were performed for minor thread diameters of 3 mm, 5 mm and 8 mm. Further calculations were done assuming a fixator-like rigid screw-plate connection. As a model of a fracture a medial bone defect was chosen. The results show a definitive influence of the screw diameter and the screw-plate connection on the load distribution in the system. Increasing screw diameter makes for lower bone stresses combined with increased bending stability, a larger part of the load being carried by the plate. The rigid screw-plate connection (plate fixator) causes less bone stresses, but high bending stresses are set up the points of screw-plate fixation. Maximal stresses for screw and bone are found at the end of the plate, caused by the large difference in the E-module between the steel plate and the bone. End-plate bone and screws are loaded in excess of their material limits when 3 mm core diameters are used, and sometimes when 5 mm core diameters are used, under the assumed conditions. When a medial bone defect reducing the bone cross-sectional area by 44% is present, the loads on the inner screws increase by a factor of 3 and the loads of the distant screws, by a factor of only 1.3. The maximal pressure in the bone cross section increases 4-fold. PMID:2281325

Seide, K; Zierold, W; Wolter, D; Kortmann, H R

1990-12-01

258

The formation mechanisms of interlocked microstructures in low-carbon high-strength steel weld metals  

SciTech Connect

Microstructural features and the formation mechanisms of interlocked microstructures of acicular ferrite in a low-carbon high-strength steel weld metal were investigated by means of computer-aided three-dimensional reconstruction technique and electron backscattered diffraction analysis. Multiple nucleation on inclusions, sympathetic nucleation or repeated nucleation, hard impingement, mutual intersection, and fixed orientation relationships of acicular ferrite grains were observed. They were all responsible for the formation of interlocked microstructures in the weld metal. During the process of isothermal transformation, the pre-formed acicular ferrite laths or plates partitioned austenite grains into many small and separate regions, and the growth of later formed acicular ferrite grains was confined in these small regions. Thus, the crystallographic grain size became smaller with the increasing holding time. Highlights: Black-Right-Pointing-Pointer Acicular ferrite is formed by multiple nucleation and sympathetic nucleation. Black-Right-Pointing-Pointer Hard impingement and intersection of ferrite grains occur at later stages. Black-Right-Pointing-Pointer The pre-formed ferrite laths partition austenite grains into smaller regions. Black-Right-Pointing-Pointer The growth of later formed ferrite grains is confined in the smaller regions.

Wan, X.L.; Wang, H.H.; Cheng, L.; Wu, K.M., E-mail: wukaiming2000@yahoo.com

2012-05-15

259

Periareolar Augmentation Mastopexy with Interlocking Gore-Tex Suture, Retrospective Review of 50 Consecutive Patients  

PubMed Central

Background Periareolar Augmentation Mastopexy is one of the most challenging operations in plastic surgery. Problems with scar quality, areolar widening, and distortion are frequent problems that interfere with a predictable result. Methods A retrospective review was performed on fifty consecutive patients who underwent a periareolar augmentation mastopexy with the interlocking approach. Of the 50 patients, 30 had both preoperative and postoperative photographs and were the basis of the study. Results The age of the patients ranged from 19 to 56 years with the average age being 39 years. The postoperative follow-up averaged 9.5 months and the implants averaged 316 mL. There were no deaths, pulmonary embolism, deep vein thrombosis, or infected implants. Four patients had complications following surgery for an overall complication rate of 13%. Two patients developed an infected Gore-Tex suture. Two of these complications were treated with revision surgery. Five patients required reoperation for an overall reoperative rate of 16% (one patient was converted to a full mastopexy). Conclusions As a result of this retrospective study, we have found the interlocking approach to periareolar augmentation/mastopexy to be a safe and reliable operation.

Kelly, Emma; Kelly, Michael

2014-01-01

260

Interlocked optimization and fast gradient algorithm for a seismic inverse problem  

SciTech Connect

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.

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

2011-08-10

261

Distal pancreatectomy with splenic preservation revisited  

PubMed Central

Background Splenic preservation (SP) during distal pancreatectomy can be accomplished by ligating the main splenic artery and vein relying on blood supply from the short gastric vessels. The purpose of this study was to examine the short-term implications of this operation, comparing it to the outcomes following distal pancreatectomy with splenectomy. Methods The records of 259 patients who underwent distal pancreatectomy with and without SP at Massachusetts General Hospital from 1994 to 2004 were reviewed. Results A total of 29% of patients underwent SP with this technique. These patients were more likely to be women (74% vs 56%, P = .008) and to have benign disease (93% vs 54%, P < .0001). Their operative times were shorter (2.5 vs 3.1 h, P < .0001), they had less blood loss (300 vs 500 ml, P < .0001) and a shorter duration of stay (6 days [interquartile range, 5 to 7] vs 7 days [interquartile range, 5 to 8], P = .001). SP was not a significant predictor of complications in either univariate (P = .445) or adjusted analysis (P = .543). One patient (1.4%) in the SP group was reoperated for splenic infarction and two patients (1.1%) in the splenectomy group for abscess and hemorrhage. There were 2 (0.8%) postoperative deaths, both in the splenectomy group. Conclusions Splenic preservation relying on blood supply from the short gastric vessels is reliable and safe and does not have a higher incidence of postoperative complications when compared to traditional distal pancreatectomy with splenectomy. The current series validates this approach and provides further evidence of its feasibility and safety. PMID:17462461

Rodriguez, J. Ruben; Madanat, Michael G.; Healy, Brian C.; Thayer, Sarah P.; Warshaw, Andrew L.; Castillo, Carlos Fernandez-Del

2013-01-01

262

Surgical approaches to the distal radius  

Microsoft Academic Search

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

Asif M. Ilyas

2011-01-01

263

Retrograde intramedullary nailing of supracondylar femur fractures above total knee arthroplasty  

Microsoft Academic Search

Four supracondylar fractures of the femur in three patients with total knee arthroplasties were treated by retrograde intramedullary nailing using an interlocking reamed nail (GSH Nail, Smith and Nephew Richards, Memphis, TN) specifically designed for fractures of the distal femur. Three cases were acute fractures and one was a refracture through a screw hole of a previously plated supracondylar fracture.

Felix F. Jabczenski; Mark Crawford

1995-01-01

264

Nonisothermal model of single screw extrusion of generalized Newtonian fluids  

SciTech Connect

A nonisothermal model of the single screw extrusion processing of generalized Newtonian fluids is presented. Various temperature dependent forms of a generalized Newtonian fluid constitutive equation representing the Herschel-Bulkley fluid and its simplifications, including Bingham plastic, power law of Ostwald-de Waele, and Newtonian fluids, are applicable. The model includes the generally ignored transverse convection terms of the equation of energy. The importance of keeping the transverse convection terms in the analysis is demonstrated by applying the model and comparing findings to experimental results involving the transverse flow temperature distributions in single screw extruders, available in the literature. The numerical instabilities, arising principally from the convection terms, generally encountered in high-Peclet-number extrusion flows, could be eliminated by the use of the streamline upwind/Petrov-Galerkin formulation. The model is sufficiently general to accommodate Navier's wall slip at the wall boundary condition commonly encountered during the processing of gels and concentrated suspensions.

Lawal, A.; Kalyon, D.M. (Stevens Inst. of Technology, Hoboken, NJ (United States). Highly Filled Materials Inst.)

1994-07-01

265

Analysis of Eyring-Powell fluid in helical screw rheometer.  

PubMed

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

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

2014-01-01

266

Mirrored visual feedback limits distal effect anticipation.  

PubMed

Modern tools in technological environments are often characterized by a spatial separation of hand actions (operating a remote control) and their intended action effects (displayed movements of an unmanned vehicle, a robot, or an avatar on a screen). Often non-corresponding proximal and distal movement effects put high demands on the human information processing system. The present study aimed to investigate how modern technological environments influence processes of planning and controlling actions. Participants performed ipsi- or contralateral movements in response to colored stimuli, while the stimulus location had to be ignored. They did not see the stimuli and hands directly, but received visual feedback (with retained or reversed spatial relations) on a projection screen in front of them. Visual feedback retaining spatial relations led to the usual Simon effect. However, visual feedback reversing spatial relations inverted the Simon effect in ipsilateral responses, and eliminated it in contralateral responses (Exp. 1). Impairing the proximal movement-effect loop so that proprioceptive/tactile information from the moving hand was no longer a reliable source for planning and controlling actions attenuated compatibility effects (Exp. 2). Moreover, distal action effects predominated action control even for opposing body-related effects. It seemed that action control of transformed movements depended on the reliability of proprioceptive/tactile and visual information. When the amount of feature overlap between proprioception and vision was low and proprioceptive (visual) information was no longer reliable, then distal (proximal) action effects stepped forward and became crucial in controlling transformed actions. PMID:22331170

Sutter, Christine; Ladwig, Stefan

2012-04-01

267

Distal lipid storage myopathy due to PNPLA2 mutation  

Microsoft Academic Search

Distal myopathy is a group of heterogeneous disorders affecting predominantly distal muscles usually appearing from young to late adulthood with very rare cardiac complications. We report a 27-year-old man characterized clinically by distal myopathy and dilated cardiomyopathy, pathologically by lipid storage, and genetically by a PNPLA2 mutation. The patient developed weakness in his lower legs and fingers at age 20

Aya Ohkuma; Ikuya Nonaka; May Christine V. Malicdan; Satoru Noguchi; Satoru Ohji; Kyoichi Nomura; Hideo Sugie; Yukiko K. Hayashi; Ichizo Nishino

2008-01-01

268

Abstract: This paper considers an analysis of a domain of attraction within interlocked feedback model. First, we confirm that the interlocked feedback model expresses circadian rhythms. Next, we search a  

E-print Network

feedback model. First, we confirm that the interlocked feedback model expresses circadian rhythms. Next, we search a domain of attraction and responses of circadian rhythms to pulse in one or some of m of Drosophila circadian rhythm," Journal of Theoretical Biology, Vol. 210, pp. 401-406, 2001. [3] , , , , 1999

269

Wet-gas compression in twin-screw multiphase pumps  

E-print Network

)?????????????????? 9 2.3 Martin and Scott (2003)????????????????? 10 2.4 Cooper & Prang (2004)?????????????????. 12 2.5 University of Hannover (2004)??????????????. 13 2.6 Model Comparisons and Thermal Issues??????????.. 14 III METHODS... screws, a GVF of 95% is recommended to ensure that there is sufficient liquid in the pump. 3.4 High Viscosity Fluid Circulation Singh 6,7 , Martin 8,9 , and Cooper & Prang 13 have all presented evidence that shows that increasing the viscosity...

Chan, Evan

2009-05-15

270

Empirical modeling of a Lysholm helical screw expander  

Microsoft Academic Search

Testing of a Lysholm helical screw expander having a rotor diameter of 5.12 inches and an expansion ratio of 5.3 was performed with simulated geothermal fluid at an inlet pressure of 120 psia. The inlet quality, engine speed and pressure ratio were independently varied to produce a three-dimensional data matrix of 104 data points. Statistical curve fitting methods were adapted

K. A. Brown

1984-01-01

271

Cellulose and the twofold screw axis: modeling and experimental arguments  

Microsoft Academic Search

Crystallography indicates that molecules in crystalline cellulose either have twofold screw-axis (21) symmetry or closely approximate it, leading to short distances between H4 and H1? across the glycosidic linkage. Therefore,\\u000a modeling studies of cellobiose often show elevated energies for 21 structures, and experimental observations are often interpreted in terms of intramolecular strain. Also, some computer models\\u000a of cellulose crystallites have

Alfred D. French; Glenn P. Johnson

2009-01-01

272

Decompressive cervical laminectomy and lateral mass screw-rod arthrodesis. Surgical analysis and outcome  

PubMed Central

Background This study evaluates the outcome and complications of decompressive cervical Laminectomy and lateral mass screw fixation in 110 cases treated for variable cervical spine pathologies that included; degenerative disease, trauma, neoplasms, metabolic-inflammatory disorders and congenital anomalies. Methods A retrospective review of total 785 lateral mass screws were placed in patients ages 16-68 years (40 females and 70 males). All cases were performed with a polyaxial screw-rod construct and screws were placed by using Anderson-Sekhon trajectory. Most patients had 12-14-mm length and 3.5 mm diameter screws placed for subaxial and 28-30 for C1 lateral mass. Screw location was assessed by post operative plain x-ray and computed tomography can (CT), besides that; the facet joint, nerve root foramen and foramen transversarium violation were also appraised. Results No patients experienced neural or vascular injury as a result of screw position. Only one patient needed screw repositioning. Six patients experienced superficial wound infection. Fifteen patients had pain around the shoulder of C5 distribution that subsided over the time. No patients developed screw pullouts or symptomatic adjacent segment disease within the period of follow up. Conclusion decompressive cervical spine laminectomy and Lateral mass screw stabilization is a technique that can be used for a variety of cervical spine pathologies with safety and efficiency. PMID:21595968

2011-01-01

273

Distal residue-CO interaction in carbonmonoxy myoglobins: a molecular dynamics study of three distal mutants.  

PubMed Central

Six 90-ps molecular dynamics trajectories, two for each of three distal mutants of sperm whale carbonmonoxy myoglobin, are reported; solvent waters within 16 A of the active site have been included. In both His64GIn trajectories, the distal side chain remains part of the heme pocket, forming a "closed" conformation similar to that of the wild type 64N delta H tautomer. Despite a connectivity more closely resembling the N epsilon H histidine tautomer, close interactions with the carbonyl ligand similar to those observed for the wild type 64N epsilon H tautomer are prevented in this mutant by repulsive interactions between the carbonyl O and the 64O epsilon. The aliphatic distal side chain of the His64Leu mutant shows little interaction with the carbonyl ligand in either His64Leu trajectory. Solvent water molecules move into and out of the active site in the His64Gly mutant trajectories; during all the other carbonmonoxy myoglobin trajectories, including the wild type distal tautomers considered in an earlier work, solvent molecules rarely encroach closer than 6 A of the active site. These results are consistent with a recent structural interpretation of the wild type infrared spectrum, and the current reinterpretation that the distal-ligand interaction in carbonmonoxy myoglobin is largely electrostatic, not steric, in nature. Images FIGURE 5 FIGURE 7 PMID:7787018

Jewsbury, P; Kitagawa, T

1995-01-01

274

Is an alcohol ignition interlock programme a useful tool for changing the alcohol and driving habits of drink-drivers?  

Microsoft Academic Search

This study evaluates whether the completion of an alcohol ignition interlock programme (AIIP) results in lasting changes of the behaviour of drink drivers and whether such a programme is more effective than a conventional licence revocation followed by an approved doctor's assessment.In Sweden, DWI offenders can voluntarily select a 2-year AIIP in lieu of a 12-month licence revocation. The AIIP

Bo Bjerre; Ulf Thorsson

2008-01-01

275

Research in Political Sociology, Volume 17 (2008), pp. 3-42. THE INTERLOCK STRUCTURE OF THE POLICY-PLANNING  

E-print Network

and universities, charities, civic organizations, foundations, think tanks, trade associations, political lobbies the governing boards of 12 leading policy- planning organizations and changes in the structure of this network interlocks among policy-planning organizations are substantively meaningful and relatively stable

Rejaie, Reza

276

Twin screw wet granulation: the study of a continuous twin screw granulator using Positron Emission Particle Tracking (PEPT) technique.  

PubMed

In this paper, Positron Emission Particle Tracking (PEPT) techniques are utilised to track the trajectory of single particles through the mixing and conveying zones of a Twin Screw Granulator (TSG). A TSG consisting of conveying zones and mixing zones is used in this study. The mixing zones are arranged with kneading discs at an angle of 30°, 60° or 90°. Experiments were carried out using different mixing configurations with various screw speed and total mass flow rate. The PEPT data obtained were then utilised to obtain the residence time distribution (RTD) and the Peclet number in an attempt to gain some insight into the mixing of the process. The fill level of the granulator was also estimated to study the mechanism of granulation. As might be expected, it was shown that the residence time of the granulation process increases with decreasing screw speed. It also increases with increasing angle of the arrangement of kneading blocks in the mixing zones, but will decreases when powder feed rate is increased. The fill level of the mixing zone in particular increases when the screw speed decreases or when powder feed rate increases. Furthermore, the fill level of the granulator will increase when the mixing zone configuration changes from 30° to 90°. It is shown that the granulator is never fully filled, even using 90° mixer elements implying limited compaction which may explain why the granules produced are porous compared with those from a high shear mixer. Interestingly, the RTD analysis reveals that the extent of axial mixing in the mixing zone of the granulator does not change significantly for different configurations and process conditions. There is evidence of a tail in the RTD which implies some material hold up and channelling. PMID:22561951

Lee, Kai T; Ingram, Andy; Rowson, Neil A

2012-08-01

277

D0 Central Tracking Solenoid Energizatino, Controls, Interlocks and Quench Protection Initial Validation Procedures  

SciTech Connect

This note presents the inspection and tests to be performed on the DZERO solenoid energization, controls, interlocks and quench protection system before it is energized for the first time. This test is to be performed with a 5000A jumper at the end of the bus instead of the solenoid. This system is based in DZERO room 511. A copy of this note shall be annotated, signed and dated by the person coordinating the procedure; and filed with the system maintenance records. Annotations shall include comments about any aspect of the procedure that is abnormal or unsuccessful. The following inspections and tests shall be performed by persons knowledgeable about the system. Each individual test step should be reviewed and understood before proceeding with that step.

Jaskierny, W.; Hance, R.; /Fermilab

1998-01-27

278

Groovy as Domain-Specific Language in the Software Interlock System  

E-print Network

After over 7 years in operation the Software Interlock System (SIS) has become an indispensable and mission critical controls tool covering many operational areas from general machine protection to diagnostics. The growing number of running instances as much as the size of existing configurations have increased both the complexity and maintenance cost of running the SIS infrastructure. In response to those issues, new ways of configuring the system have been investigated aiming at simplifying the configuration process by making it faster, more user-friendly and understandable for wider audiences and domain experts alike. As one of the possible choices the Groovy scripting language has been considered as being particularly well suited for writing a custom Domain-Specific Language (DSL) due to its built-in language features like native syntax constructs, command chain expressions, hierarchical structures with builders, closures or Abstract Syntax Tree (AST) transformations. This document explains best practices...

Wozniak, J; Kruk, G

2014-01-01

279

Interlocking of chelae is a key factor for dominance hierarchy formation in crayfish.  

PubMed

We characterized the role of chelae during agonistic encounters of the crayfish Procambarus clarkii. Physical asymmetries in body length, body mass and chelae size were directly related to dominance hierarchy formation. More than 80% of winning crayfish had longer body and chelae lengths, and winners were usually heavier in body mass, even if their differences were less than 3% compared with losing opponents. In mismatched pairings, large crayfish with short chelae were beaten by small crayfish with large chelae. Three physical elements of body length, body mass and chelae length equally affected the outcome of agonistic bouts. Chelae restriction, in which chelae were tightly closed using rubber bands, affected the outcome of agonistic bouts between large and small crayfish. Before chelae restriction, large crayfish won in all pairings. Following chelae restriction for at least 30 days from the first encounters, the winning rate of large crayfish that were previous winners decreased significantly in the second encounters against the same opponents that were previous losers. The handicap of chelae restriction significantly prolonged the time to formation of the winner-loser relationship. Individual fights escalated during agonistic bouts between large crayfish with one chela restricted and small crayfish with intact chelae, whereas the number of fights increased but the duration of individual fights did not increase in large crayfish with both chelae restricted. Furthermore, when the chelae of both large and small crayfish were disabled, the dominance order was frequently not formed during 30 min of agonistic bouts. Preventing chelae from interlocking prevented escalation of agonistic bouts. We show that interlocking of chelae acted as a key factor for the formation of dominance hierarchy. PMID:22837457

Ueno, Ryusuke; Nagayama, Toshiki

2012-08-15

280

Comminuted fracture of the distal sesamoid bone and distal rupture of the deep digital flexor tendon.  

PubMed

A 10-year-old show jumper was evaluated for an acute severe lameness (grade 4 of 5) of the right foreleg. During weight bearing, the toe of the affected limb rotated dorsally suggesting rupture of the deep digital flexor tendon (DDFT). Upon radiographic examination of the hoof, a severe erosion at the flexor surface and a parasagittal fracture of the distal sesamoid bone were found. Ultrasonographic examination confirmed rupture of the DDFT. These findings were confirmed on post-mortem examination. Prior to the acute lameness, the horse was treated with corticosteroid injections into the podotrochlear bursa. Repeated intra-bursal injections of corticosteroids as a possible cause for DDFT rupture are discussed as well as the possible association between a degenerative distal sesamoid bone, a distal sesamoid bone fracture and a DDFT rupture. PMID:16050282

Hoegaerts, Michel; Pille, Frederik; De Clercq, Tom; Fulton, Ian C; Saunders, Jimmy H

2005-01-01

281

Feasibility of Bilateral Crossing C7 Intralaminar Screws: A Cadaveric Study  

PubMed Central

Objective When the pedicle screw insertion technique is failed or not applicable, C7 intralaminar screw insertion method has been used as an alternative or salvage fixation method recently. However, profound understanding of anatomy is required for safe application of the bilaterally crossing laminar screw at C7 in clinic. In this cadaveric study, we evaluated the anatomic feasibility of the bilateral crossing intralaminar screw insertion and especially focused on determination of proper screw entry point. Methods The C7 vertebrae from 18 adult specimens were studied. Morphometric measurements of the mid-laminar height, the minimum laminar thickness, the maximal screw length, and spino-laminar angle were performed and cross-sectioned vertically at the screw entry point (spino-laminar junction). The sectioned surface was equally divided into 3 parts and maximal thickness and surface area of the parts were measured. All measurements were obtained bilaterally. Results The mean mid-laminar height was 13.7 mm, mean minimal laminar thickness was 6.6 mm, mean maximal screw length was 24.6 mm, and mean spinolaminar angle was 50.8±4.7°. Based on the measured laminar thickness, the feasibility of 3.5 mm diameter intralaminar screw application was 83.3% (30 sides laminae out of total 36) when assuming a tolerance of 1 mm on each side. Cross-sectional measurement results showed that the mean maximal thickness of upper, middle, and lower thirds was 5.0 mm, 7.5 mm, and 7.3 mm, respectively, and mean surface area for each part was 21.2 mm2, 46.8 mm2, and 34.7 mm2, respectively. Fourteen (38.9%) sides of laminae would be feasible for 3.5 mm intralaminar screw insertion when upper thirds of C7 spino-laminar junction is the screw entry point. In case of middle and lower thirds of C7 spino-laminar junction, 32 (88.9%) and 28 (77.8%) sides of laminae were feasible for 3.5 mm screw insertion, respectively. Conclusion The vertical cross-sectioned area of middle thirds at C7 spinolaminar junction was the largest area and 3.5 mm screw can be accommodated with 77.8% of feasibility when lower thirds were the screw entry point. Thus, selection of middle and lower thirds for each side of screw entry point in spino-laminar junction would be the safest way to place bilateral crossing laminar screw within the entire lamina. This anatomic study result will help surgeons to place the screw safely and accurately.

Baek, Tae-Hyun; Hong, Jae-Taek; Kim, Daniel H.; Shin, Dongsuk; Lee, Sang-Won

2014-01-01

282

Distal penile prosthesis extrusion: treatment with distal corporoplasty or Gortex windsock reinforcement.  

PubMed

Subcutaneous extrusion of penile prosthesis cylinders beneath the glans penis is an unusual but difficult complication of penile prosthesis. Without surgical repair, extrusion, infection, and corporeal fibrosis may ensue. Twenty-eight patients with distal corporeal extrusion were reviewed to identify the optimum treatment outcome for these penile prosthesis complications. Records of 28 men with subcutaneous distal penile prosthesis cylinder extrusion were reviewed. Mean age was 56.2 y. Etiology of erectile dysfunction was diabetes mellitus in 11, vasculogenic in 10, Peyronie's disease in five, radical pelvic surgery in five. Duration of penile prosthesis was 8-72 months (mean 42.6). No patient had penile prosthesis infection or device exposure through the skin. Distal corporoplasty was treated on 18/28 men using cylinder repositioning and direct tunica albuginea repair. Ten men underwent repair using a Gortex windsock. 8/18 corporoplasty and 6/10 windsock patients required glans fixation for treatment of hypermobile glans following cylinder relocation. In two patients with windsock repair, extrusion recurrence occurred 6 and 18 months following surgery and 1/6 had post operative infection requiring prosthesis removal. Mean surgical time for corporoplasty was 52.8 minutes while windsock reconstruction was 89.6 minutes. Distal subcutaneous penile prosthesis cylinder extrusion produces coital pain and predisposes to cylinder exposure and infection. Early repair with or without additional prosthetic materials will return penile prostheses to a normal functioning state. Distal corporoplasty with cylinder repositioning appears to be a simple, low morbidity solution to this difficult dilemma. Outcomes with distal corporoplasty result in better function, less pain, and fewer recurrences than Gortex windsock repair. PMID:11979321

Carson, C C; Noh, C H

2002-04-01

283

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

284

Distal Renal Tubular Acidosis and Calcium Nephrolithiasis  

NASA Astrophysics Data System (ADS)

Calcium stones are commonly encountered in patients with congenital distal renal tubular acidosis, a disease of renal acidification caused by mutations in either the vacuolar H+-ATPase (B1 or a4 subunit), anion exchanger-1, or carbonic anhydrase II. Based on the existing database, we present two hypotheses. First, heterozygotes with mutations in B1 subunit of H+-ATPase are not normal but may harbor biochemical abnormalities such as renal acidification defects, hypercalciuria, and hypocitraturia which can predispose them to kidney stone formation. Second, we propose at least two mechanisms by which mutant B1 subunit can impair H+-ATPase: defective pump assembly and defective pump activity.

Moe, Orson W.; Fuster, Daniel G.; Xie, Xiao-Song

2008-09-01

285

VSHOT Measurements of Distal II Dish Concentrators  

SciTech Connect

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.

Jones, S.A.

1998-12-14

286

Thoracic Aortic Stent-Graft Placement for Safe Removal of a Malpositioned Pedicle Screw  

SciTech Connect

We describe a case of percutaneous placement of a thoracic aortic stent-graft for safe removal of a malpositioned pedicle screw in a 52-year-old man. The patient had undergone posterior thoracic spinal instrumentation for pyogenic spondylitis and spinal deformity 8 months previously. Follow-up CT images showed a malpositioned pedicle screw which was abutting the thoracic aorta at the T5 level. After percutaneous stent-graft placement, the malpositioned pedicle screw was safely and successfully removed.

Hu Hongtao [Henan Tumor Hospital, Department of Radiology (China); Shin, Ji Hoon, E-mail: jhshin@amc.seoul.kr; Hwang, Jae-Yeon; Cho, Young Jun; Ko, Gi-Young; Yoon, Hyun-Ki [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology (Korea, Republic of)

2010-10-15

287

Surgical strategies to improve fixation in the osteoporotic spine: the effects of tapping, cement augmentation, and screw trajectory.  

PubMed

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

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

2014-02-01

288

Accuracy of Free Hand Pedicle Screw Installation in the Thoracic and Lumbar Spine by a Young Surgeon: An Analysis of the First Consecutive 306 Screws Using Computed Tomography  

PubMed Central

Study Design A retrospective cross-sectional study. Purpose The purpose of this study is to evaluate the accuracy and safety of free-hand pedicle screw insertion performed by a young surgeon. Overview of Literature Few articles exist regarding the safety of the free-hand technique without inspection by an experienced spine surgeon. Methods The index surgeon has performed spinal surgery for 2 years by himself. He performed fluoroscopy-assisted pedicle screw installation for his first year. Since then, he has used the free-hand technique. We retrospectively reviewed the records of all consecutive patients undergoing pedicle screw installation using the free-hand technique without fluoroscopy in the thoracic or lumbar spine by the index surgeon. Incidence and extent of cortical breach by misplaced pedicle screw was determined by a review of postoperative computed tomography (CT) images. Results A total of 36 patients received 306 free-hand placed pedicle screws in the thoracic or lumbar spine. A total of 12 screws (3.9%) were identified as breaching the pedicle in 9 patients. Upper thoracic spine was the most frequent location of screw breach (10.8%). Lateral breach (2.3%) was more frequent than any other direction. Screw breach on the right side (9 patients) was more common than that on the left side (3 patients) (p<0.01). Conclusions An analysis by CT scan shows that young spine surgeons who have trained under the supervision of an experienced surgeon can safely place free-hand pedicle screws with an acceptable breach rate through repetitive confirmatory steps. PMID:24967036

Lee, Chang-Hyun; Kim, Yongjung J; Kim, Ki-Jeong; Jahng, Tae-Ahn; Kim, Hyun-Jib

2014-01-01

289

A description of the dynamics of manipulators using screw theory  

NASA Astrophysics Data System (ADS)

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.

Akselrod, B. V.

1985-04-01

290

Helical rotary screw expanders to generate electricity from geothermal brines  

SciTech Connect

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%.

Not Available

1983-09-01

291

Pedicle Screw-Based Posterior Dynamic Stabilization: Literature Review  

PubMed Central

Posterior dynamic stabilization (PDS) indicates motion preservation devices that are aimed for surgical treatment of activity related mechanical low back pain. A large number of such devices have been introduced during the last 2 decades, without biomechanical design rationale, or clinical evidence of efficacy to address back pain. Implant failure is the commonest complication, which has resulted in withdrawal of some of the PDS devices from the market. In this paper the authors presented the current understanding of clinical instability of lumbar motions segment, proposed a classification, and described the clinical experience of the pedicle screw-based posterior dynamic stabilization devices. PMID:23227349

Sengupta, Dilip K.; Herkowitz, Harry N.

2012-01-01

292

Equine laminitis caused by distal displacement of the distal phalanx: 12 cases (1976-1985).  

PubMed

Clinical data from 12 cases of equine laminitis characterized by distal displacement of the distal phalanx (P3) were reviewed. Clinical features of horses that survived the syndrome were compared with the nonsurvivors to obtain prognostic indicators. Animals affected included 8 Quarter Horses, 2 Welsh ponies, 1 Thoroughbred, and 1 Arabian. Eight of the animals were females (67%), 2 were stallions, and 2 were geldings. The mean age of affected animals was 8.6 years (2 to 14 years), and the mean body weight was 442 kg. The survivors weighed less than the nonsurvivors (384 kg vs 473 kg, respectively), suggesting that body weight may be of prognostic value for horses affected with distal displacement of P3. Ten of the 12 animals (83%) were admitted because of a disorder other than laminitis, but subsequently developed laminitis during the treatment period. All affected animals had clinical evidence of endotoxemia and/or sepsis before the onset of laminitis. Cavitation or depression of the dorsal coronary band was detected in all animals and was the most reliable clinical indicator of distal displacement of P3. Five horses had fluid (blood or serum) ooze from their coronary bands and 2 of these sloughed one or more of their hooves. Necropsy findings of the 8 horses that were euthanatized included severe hemorrhagic, congested laminae and complete detachment of P3 from the hoof wall. Histologic examination of affected laminae revealed vascular thrombosis and multifocal areas of hemorrhage and necrosis. Radiography failed to reveal distal displacement of P3 in 8 animals, but the remaining 4 animals had an accentuation of the dorsal proximal hoof wall and cavitation of the coronary band visible on lateral radiographs. PMID:3744996

Baxter, G M

1986-08-01

293

Reducing radiation exposure in intra-medullary nailing procedures: intra-medullary endo-transilluminating (iMET).  

PubMed

The purpose of the study was to reduce the level of radiation exposure during intra-medullary nailing procedures. A visible light source was inserted into the medullary bone cavity in order to detect the distal interlocking screw holes. The light penetrates out of the bone surface, revealing the position of the screw hole, and this allows the subsequent drilling and placing of the interlocking screw to be free of fluoroscopy. Among the 19 consecutive tibia-fracture patients recruited for this study, no repetition of the drilling procedure or insertion of a transverse interlocking screw was needed. The average time to finish the insertion of one distal interlocking screw was 4.1+/-1.8 min. It was extrapolated that 13-41% of previous radiation exposure levels could be saved. The non-fluoroscopic approach thus decreases the health hazards that the patients are experiencing as well as those of the surgical team who need to perform such intra-medullary nailing operations on a routine basis. PMID:19524231

Chu, William; Wang, Jyhpyng; Young, Shuenn-Tsong; Chu, Woei Chyn

2009-10-01

294

Biomechanical impact of C2 pedicle screw length in an atlantoaxial fusion construct  

PubMed Central

Background: Posterior, atlantoaxial (AA) fusions of the cervical spine may include either standard (26 mm) or short (16 mm) C2 pedicle screws. This manuscript focused on an in vitro biomechanical comparison of standard versus short C2 pedicle screws to perform posterior C1-C2 AA fusions. Methods: Twelve human cadaveric spines underwent C1 lateral mass screw and standard C2 pedicle screw (n = 6) versus short C2 pedicle screw (n = 6) fixation. Six additional controls were not instrumented. The peak torque, peak rotational interval, and peak stiffness of the constructs were analyzed to failure levels. Results: The peak torque to construct failure was not statistically significantly different among the control spine (12.2 Nm), short pedicle fixation (15.5 Nm), or the standard pedicle fixation (11.6 Nm), P = 0.79. While the angle at the peak rotation statistically significantly differed between the control specimens (47.7° of relative motion) and the overall instrumented specimens (P < 0.001), the 20.7° of relative rotation in the short C2 pedicle screw specimens was not statistically significantly higher than the 13.7° of relative rotation in the standard C2 pedicle screw specimens (P = 0.39). Similarly, although the average stiffness was statistically significantly lower in control group (0.026 Nm/degree) versus the overall instrumented specimens (P = 0.001), the standard C2 pedicle screws (2.54 Nm/degree) did not differ from the short C2 pedicle screws Conclusions: Both standard and short C2 pedicle screws allow for equally rigid fixation of C1 lateral mass-C2 AA fusions. Usage of a short C2 pedicle screw may be an acceptable method of stabilization in carefully selected patient populations. PMID:25289157

Xu, Risheng; Bydon, Mohamad; Macki, Mohamad; Belkoff, Stephen M.; Langdale, Evan R.; McGovern, Kelly; Wolinsky, Jean-Paul; Gokalsan, Ziya L.; Bydon, Ali

2014-01-01

295

Distal Xq duplication and functional Xq disomy  

PubMed Central

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

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

2009-01-01

296

Metal-organic and supramolecular architectures based on mechanically interlocked molecules  

NASA Astrophysics Data System (ADS)

The focus of this work is on mechanically interlocked molecules (MIMs), which have unusual physicochemical and mechanical properties with potential applications in nano-scale/molecular devices and high strength materials. Rotaxanes, for example, consist of an axle-like molecule threaded through a wheel-like molecule, with bulky groups at the two ends of the axle preventing the wheel from dissociating. The position of the wheel along the axle can be switched in a controllable and reversible manner by applying external stimuli, a feature that might lead to the next generation of computers. Molecularly woven materials (MWMs), another example of molecules with mechanically interlocked features, are predicted to be unprecedentedly strong while being lightweight and flexible. With the ultimate goal of achieving control over the functioning of molecular devices in the solid state, a variety of pseudorotaxane building blocks were prepared and characterized, including a novel, rare blue-colored motif. The temperature-dependent assembly/disassembly of pseudorotaxanes was exploited for the construction of single-wavelength colorimetric temperature sensors over a 100 °C window. Pseudorotaxanes based on aromatic crown ether wheels and disubstituted 4,4'-bipyridinium axles were converted into rotaxanes upon binding to metal complexes (zinc, cadmium, mercury, copper, cobalt), and the formation of ordered crystalline arrays was studied in the solid state. The columnar organization of pseudorotaxanes by Hg2X6 2-- complexes (X = Cl, Br, I), leading to unprecedented dichroic (blue/red) rotaxane crystals, was demonstrated for the first time. From the crystal structures studied it became apparent that negatively charged metal complexes are needed for successful assembly with the positively charged pseudorotaxane units. To be able to use the more common, positively charged metal ions for rotaxane framework construction, neutral and negatively charged pseudorotaxanes were synthesized, by attaching anionic substituents (carboxylates, sulfonates) to either the wheel or the axle component. It was found that pseudorotaxane formation also enabled resolution of two sulfonated crown ether isomers, which were inseparable by conventional methods. Organic ligands for MWM precursors were designed and synthesized according to multi-step schemes. Helical metal-complexes based on these ligands were prepared and characterized. Chromatography, Nuclear Magnetic Resonance and UV-Visible spectroscopy, Mass spectrometry, Electrochemistry, Thermogravimetric Analysis and X-ray crystallography were used in identification, purification and characterization of the compounds involved.

Fernando, Isurika Rosini

297

Prosopis pubescens (screw bean mesquite) seedlings are hyperaccumulators of copper.  

PubMed

Due to health reasons, toxic metals must be removed from soils contaminated by mine tailings and smelter activities. The phytoremediation potential of Prosopis pubescens (screw bean mesquite) was examined by use of inductively-coupled plasma optical emission spectroscopy. Transmission electron microscopy was used to observe ultrastructural changes of parenchymal cells of leaves in the presence of copper. Elemental analysis was used to localize copper within leaves. A 600-ppm copper sulfate exposure to seedlings for 24 days resulted in 31,000 ppm copper in roots, 17,000 ppm in stems, 11,000 in cotyledons and 20 ppm in the true leaves. For a plant to be considered a hyperaccumulator, the plant must accumulate a leaf-to-root ratio <1. Screw bean mesquite exposed to copper had a leaf-to-root ratio of 0.355 when cotyledons were included. We showed that P. pubescens grown in soil is a hyperaccumulator of copper. We recommend that this plant should be field tested. PMID:23612918

Zappala, Marian N; Ellzey, Joanne T; Bader, Julia; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge

2013-08-01

298

Chemical Engineering Science 54 (1999) 999--1013 Analysis of nonisothermal screw extrusion processing of  

E-print Network

Abstract Analytical solutions are developed for the flow and heat transfer in nonisothermal screw extrusionChemical Engineering Science 54 (1999) 999--1013 Analysis of nonisothermal screw extrusion processing of viscoplastic fluids with significant back flow Adeniyi Lawal *, Dilhan M. Kalyon Department

299

Analysis of nonisothermal screw extrusion processing of viscoplastic fluids with significant back flow  

Microsoft Academic Search

Analytical solutions are developed for the flow and heat transfer in nonisothermal screw extrusion processing of viscoplastic fluids with pressure back flow. The screw geometry is assumed to be shallow and the flight width small, thus enabling the flow to be modeled as that occurring between two infinitely long parallel plates, i.e., the generalized Couette flow. The constitutive equation is

Adeniyi Lawal; Dilhan M. Kalyon

1999-01-01

300

Retrieval of a fractured abutment screw thread from an implant: a case report  

Microsoft Academic Search

This report describes the management of a loose cement-retained implant supported crown where the thread of the abutment screw had fractured away from the body of the screw and was retained within the implant. The importance of multi-disciplinary skills in the treatment of patients with implants is discussed.

L. Rickman; J. Satterthwaite

2008-01-01

301

Terramechanics-based propulsive characteristics of mobile robot driven by Archimedean screw mechanism on soft soil  

Microsoft Academic Search

This paper describes the mathematical modeling and the propulsive characteristics of a novel robot driven by Archimedean screw mechanisms, named Screw Drive Rover. For secure locomotion on soft soil, the proposed rover would become one of the good solutions because of its robustness to slipping and getting stuck in the soil. Furthermore, the rover is expected to move in various

Kenji Nagaoka; Masatsugu Otsuki; Takashi Kubota; Satoshi Tanaka

2010-01-01

302

Tracking Control of Flexible Ball Screw Drives With Runout Effect and Mass Variation  

Microsoft Academic Search

Most machine tools rely on precision ball screw drives to accurately position the workpiece relative to the tool. The quality of the machining outcome depends significantly on the tracking performance of the workpiece position over a desired trajectory. This paper addresses the minimization of the tracking error in a ball screw drive system in the presence of dynamic variations. Three

Daniel Sepasi; Ryozo Nagamune; Farrokh Sassani

2012-01-01

303

Initial fixation strength of polylactic acid interference screws in anterior cruciate ligament reconstruction  

Microsoft Academic Search

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

JA Abate; PD Fadale; MJ Hulstyn; WR Walsh

1998-01-01

304

Factors associated with the stability of titanium screws placed in the posterior region for orthodontic anchorage  

Microsoft Academic Search

Recently, implant anchors such as titanium screws have been used for absolute anchorage during edgewise treatment. However, there have been few human studies reporting on the stability of implant anchors placed in the posterior region. The purpose of this study was to examine the success rates and to find the factors associated with the stability of titanium screws placed into

Shouichi Miyawaki; Isao Koyama; Masahide Inoue; Katsuaki Mishima; Toshio Sugahara; Teruko Takano-Yamamoto

2003-01-01

305

Development of Solid-Lubricated Ball-Screws for Use in Space.  

National Technical Information Service (NTIS)

Ball-screws lubricated by solid lubricant films containing molybdenum disulphide are developed. The ball-screws (shaft diameter: phi 25 mm, length: 667 mm) were operated under a load of 40 to 120 N at a speed of 1.5 to 200 rpm at 10(exp -5) Pa. First, bal...

M. Chiba, T. Gyougi, M. Nishimura, K. Seki

1991-01-01

306

Biomechanical and histomorphometric analyses of monocortical screws at placement and 6 weeks postinsertion.  

PubMed

Maxillofacial screws are increasingly being used in orthodontics to provide anchorage for tooth movement. The objective of this study was to determine the biomechanical stability as well as the bone tissue response of screws at 6 weeks postinsertion in a canine model. Seven skeletally mature male dogs received 102 screws (2 x 6 mm or 2 x 8 mm) at predetermined sites. Twenty screws became loose or were lost during the 6-week undisturbed healing period. Forty-eight screws were randomized for mechanical testing and 34 for histology. Peak pullout strength was recorded and approximately 80-microm sections were examined for histomorphometric parameters. Statistical analyses were conducted by analysis of variance and Tukey-Kramer method. Mean +/- SE peak pullout strengths for the various sites ranged from 153.5 +/- 37.6 N to 389.3 +/- 32.5 N with no significant (P < .05) differences at immediate placement and 6 weeks postinsertion. Bone contact ranged from 79% to 95%. Histomorphometric analyses indicated higher bone formation rate in the mandible than in the maxilla and a gradient of decreasing turnover with increasing distance from the screw interface. These results provide the clinical orthodontist with an estimate of the holding power of these screws and an understanding of early biological healing response associated with self-drilling screws. PMID:16836174

Huja, S S; Rao, J; Struckhoff, J A; Beck, F M; Litsky, A S

2006-01-01

307

Electrical characterization of 4H-SiC avalanche photodiodes containing threading edge and screw dislocations  

Microsoft Academic Search

The reverse voltage current characteristics and electroluminescence of small area 4H-SiC avalanche photodiodes were investigated and correlated with the presence of threading screw and edge dislocations. Localized electroluminescence was observed at threading dislocations at voltages close to breakdown whereas diodes without any extended defects exhibited uniform light emission in the active area. Diodes containing either edge or screw dislocations were

R. A. Berechman; M. Skowronski; S. Soloviev; P. Sandvik

2010-01-01

308

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

PubMed Central

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

2014-01-01

309

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

E-print Network

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...

Kroupa, Ryan Daniel

2012-07-16

310

Mathematical modeling of the working cycle of oil injected rotary twin screw compressor  

Microsoft Academic Search

Oil injected twin-screw air and gas compressors are widely used for medium pressure applications in many industries. Low cost air compressors can be adopted for compression of helium and special gases, leading to significant cost saving. Mathematical analysis of oil injected twin-screw compressor is carried out on the basis of the laws of perfect gas and standard thermodynamic relations. Heat

N. Seshaiah; Subrata Kr. Ghosh; R. K. Sahoo; Sunil Kr. Sarangi

2007-01-01

311

16 CFR Figure 6 to Part 1633 - Burner Assembly Showing Arms and Pivots (Shoulder Screws), in Relation to, Portable Frame...  

Code of Federal Regulations, 2010 CFR

...Screws), in Relation to, Portable Frame Allowing Burner Height Adjustment 6 Figure 6 to Part 1633 Commercial Practices...Screws), in Relation to, Portable Frame Allowing Burner Height Adjustment...

2010-01-01

312

16 CFR Figure 6 to Part 1633 - Burner Assembly Showing Arms and Pivots (Shoulder Screws), in Relation to, Portable Frame...  

Code of Federal Regulations, 2013 CFR

...Screws), in Relation to, Portable Frame Allowing Burner Height Adjustment 6 Figure 6 to Part 1633 Commercial Practices...Screws), in Relation to, Portable Frame Allowing Burner Height Adjustment...

2013-01-01

313

16 CFR Figure 6 to Part 1633 - Burner Assembly Showing Arms and Pivots (Shoulder Screws), in Relation to, Portable Frame...  

...Screws), in Relation to, Portable Frame Allowing Burner Height Adjustment 6 Figure 6 to Part 1633 Commercial Practices...Screws), in Relation to, Portable Frame Allowing Burner Height Adjustment...

2014-01-01

314

The Contributions of Interlocking Loops and Extensive Nonlinearity to the Properties of Circadian Clock Models  

PubMed Central

Background Sensitivity and robustness are essential properties of circadian clock systems, enabling them to respond to the environment but resist noisy variations. These properties should be recapitulated in computational models of the circadian clock. Highly nonlinear kinetics and multiple loops are often incorporated into models to match experimental time-series data, but these also impact on model properties for clock models. Methodology/Principal Findings Here, we study the consequences of complicated structure and nonlinearity using simple Goodwin-type oscillators and the complex Arabidopsis circadian clock models. Sensitivity analysis of the simple oscillators implies that an interlocked multi-loop structure reinforces sensitivity/robustness properties, enhancing the response to external and internal variations. Furthermore, we found that reducing the degree of nonlinearity could sometimes enhance the robustness of models, implying that ad hoc incorporation of nonlinearity could be detrimental to a model's perceived credibility. Conclusion The correct multi-loop structure and degree of nonlinearity are therefore critical in contributing to the desired properties of a model as well as its capacity to match experimental data. PMID:21152419

Saithong, Treenut; Painter, Kevin J.; Millar, Andrew J.

2010-01-01

315

String Electron and Three-ring Quarked Nucleons' Transverse Interlocks Build Atoms, Vindicate Schr"odinger  

NASA Astrophysics Data System (ADS)

Flatland electron loop strings have transversely vibrating neutrino strings. Traveling waves TWs alternately become upwardly deflecting standing waves SWs along each half-wave segment between non-vibrating node pairs. Descending SWs revert to TWs at flatland, proceeding to the next adjacent nodal pair; folding continues. New SWs descend, then ascend; repetition follows to a three dimensional object. Broken ``linear'' electron string and spring constant compress within stars so linear mass density allows incorporation into stable three-ring proton string, creating neutron of two down quarks, one up. It is unstable; it lacks overpass-underpass interlocks of proton that merged linear charge density of two up quarks and one down quark with the electron, becoming neutral. Any transversely aligned neutron notch pushed into acceptor notch of proton is ionized deuterium; tritium follows. Alpha particle is a stable ``tic-tac-toe'' grid. Atom building proceeds routinely, nucleon attachment follows chemical and physical property requirements. Models require vindication of Schr"odinger's actual, but incomplete, wave model of electron with physical extent over his wave, and question Heisenberg's uncertainty proposal.

McLeod, David; McLeod, Roger David

2008-05-01

316

A bio-inspired swellable microneedle adhesive for mechanical interlocking with tissue  

NASA Astrophysics Data System (ADS)

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.

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

317

Segmented instrumentation tube including a locking sleeve for interlocking the segments of the instrumentation tube  

DOEpatents

Segmented instrumentation tube including a locking sleeve for interlocking the segments of the instrumentation tube, so that the threaded ends of the instrumentation tube do not unthread when subjected to vibration, such an instrumentation tube being suitable for use in a nuclear reactor pressure vessel. The instrumentation tube has a first member having a threaded end portion that has a plurality of first holes circumferentially around the outside surface thereof. The instrumentation tube also has a second member having a threaded end portion that has a plurality of second holes circumferentially around the outside surface thereof. The threads of the second member are caused to threadably engage the threads of the first member for defining a threaded joint there between. A sleeve having an inside surface surrounds the end portion of the first member and the end portion of the second member and thus surrounds the threaded joint. The sleeve includes a plurality of first projections and second projections that outwardly extend from the inside surface to engage the first holes and the second holes, respectively. The outside surface of the sleeve is crimped or swaged at the locations of the first projections and second projections such that the first projections and the second projections engage their respective holes. In this manner, independent rotation of the first member with respect to the second member is prevented, so that the instrumentation tube will not unthread at its threaded joint. 10 figures.

Obermeyer, F.D.

1993-11-16

318

Septum magnet MNP-23 for the CERN PS experimental area and its fast interlock system  

E-print Network

Two MNP-23 septum-like magnets are installed at CERN in the transfer line from the Proton Synchrotron (PS) to the East Hall Experimental Area. They are exposed to extremely high doses of ionizing radiation. In the past, the magnets experienced two catastrophic failures due to overheating of its coils and cannot be repaired. The magnets of improved design which is subject of this article are built as replacements for the magnets presently installed. The MNP-23 is a resistive C shaped iron-dominated magnet made of solid low carbon steel blocks. The excitation windings consist of two water-cooled coils wound from hollow copper conductor. The septum design of these magnets implies a high current density which requires an efficient water cooling system. The newly designed cooling circuit provides better cooling performance and more reliability. To avoid failures due to coil overheating, an elaborate interlock system was developed and installed. It consists of two parts: firstly a slow, more classic sensor, to dete...

Borburgh, J; Prost, A; Zickler, T

2004-01-01

319

Supervision Software for the Integration of the Beam Interlock System with the CERN Accelerator Complex  

E-print Network

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...

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

320

Atlantoaxial transarticular screw fixation and posterior fusion using ultra-high-molecular-weight polyethylene cable.  

PubMed

This article attempts to evaluate the effectiveness of the ultra-high-molecular-weight polyethylene (UHMW-PE) cable system in atlantoaxial transarticular screw fixation and posterior fusion through the clinical results of 10 postoperative patients with atlantoaxial subluxation secondary to rheumatoid arthritis. Among them, one patient with only one screw placed owing to an anomalous vertebral artery had the correction loss of the 3-mm atlas-dens interval after surgery. Another patient had a second operation to remove the screw and cable after 2 years 11 months because a unilateral transarticular screw had come to protrude through the lateral mass of the atlas ventrally. All patients had achieved C1-C2 osseous fusion without any complications associated with this cable system. The UHMW-PE cable is a very useful material as sublaminar wiring in atlantoaxial transarticular screw fixation and posterior fusion. PMID:16189448

Yonezawa, Ikuho; Arai, Yasuhisa; Tsuji, Takaaki; Takahashi, Masaki; Kurosawa, Hisashi

2005-10-01

321

Use of a quantitative pedicle screw accuracy system to assess new technology: Initial studies on O-arm navigation and its effect on the learning curve of percutaneous pedicle screw insertion  

Microsoft Academic Search

BackgroundA quantitative screw accuracy system is proposed that allows for high-fidelity discrimination between various methods of pedicle screw insertion. Our purpose was to study the utility of a quantitative screw accuracy scoring system to assess new imaging technologies and their effects on the minimally invasive spine learning curve.

Joseph A. Sclafani; Gilad J. Regev; Jonathan Webb; Steven R. Garfin; Choll W. Kim

2011-01-01

322

Magnetic resonance imaging analysis of the bioabsorbable Milagro™ interference screw for graft fixation in anterior cruciate ligament reconstruction  

Microsoft Academic Search

Ligament graft fixation with bioabsorbable interference screws is a standard procedure in cruciate ligament replacement. Previous\\u000a screw designs may resorb incompletely, and can cause osteolysis and sterile cysts despite being implanted for several years.\\u000a The aim of this study was to examine the in vivo degradation and biocompatibility of the new Milagro™ interference screw (Mitek,\\u000a Norderstedt, Germany). The Milagro™ interference screw

K.-H. Frosch; T. Sawallich; G. Schütze; A. Losch; T. Walde; P. Balcarek; F. Konietschke; K. M. Stürmer

2009-01-01

323

Novel free-hand T1 pedicle screw method: Review of 44 consecutive cases  

PubMed Central

Summary of Background Data: Multilevel posterior cervical instrumented fusions are becoming more prevalent in current practice. Biomechanical characteristics of the cervicothoracic junction may necessitate extending the construct to upper thoracic segments. However, fixation in upper thoracic spine can be technically demanding owing to transitional anatomy while suboptimal placement facilitates vascular and neurologic complications. Thoracic instrumentation methods include free-hand, fluoroscopic guidance, and CT-based image guidance. However, fluoroscopy of upper thoracic spine is challenging secondary to vertebral geometry and patient positioning, while image-guided systems present substantial financial commitment and are not readily available at most centers. Additionally, imaging modalities increase radiation exposure to the patient and surgeon while potentially lengthening surgical time. Materials and Methods: Retrospective review of 44 consecutive patients undergoing a cervicothoracic fusion by a single surgeon using the novel free-hand T1 pedicle screw technique between June 2009 and November 2012. A starting point medial and cephalad to classic entry as well as new trajectory were utilized. No imaging modalities were employed during screw insertion. Postoperative CT scans were obtained on day 1. Screw accuracy was independently evaluated according to the Heary classification. Results: In total, 87 pedicle screws placed were at T1. Grade 1 placement occurred in 72 (82.8%) screws, Grade 2 in 4 (4.6%) screws and Grade 3 in 9 (10.3%) screws. All Grade 2 and 3 breaches were <2 mm except one Grade 3 screw breaching 2-4 mm laterally. Only two screws (2.3%) were noted to be Grade 4, both breaching medially by less than 2 mm. No new neurological deficits or returns to operating room took place postoperatively. Conclusions: This modification of the traditional starting point and trajectory at T1 is safe and effective. It attenuates additional bone removal or imaging modalities while maintaining a high rate of successful screw placement compared to historical controls.

Rivkin, Mark A.; Okun, Jessica F.; Yocom, Steven S.

2014-01-01

324

Evaluation of contributions of orthodontic mini-screw design factors based on FE analysis and the Taguchi method.  

PubMed

This study determines the relative effects of changes in bone/mini-screw osseointegration and mini-screw design factors (length, diameter, thread shape, thread depth, material, head diameter and head exposure length) on the biomechanical response of a single mini-screw insertion. Eighteen CAD and finite element (FE) models corresponding to a Taguchi L(18) array were constructed to perform numerical simulations to simulate mechanical responses of a mini-screw placed in a cylindrical bone. The Taguchi method was employed to determine the significance of each design factor in controlling strain. Simulation results indicated that mini-screw material, screw exposure length and screw diameter were the major factors affecting bone strain, with percentage contributions of 63%, 24% and 7%, respectively. Bone strain decreased obviously when screw material had the high elastic modulus of stainless/titanium alloys, a small exposure length and a large diameter. Other factors had no significant on bone strain. The FE analysis combined with the Taguchi method efficiently identified the relative contributions of several mini-screw design factors, indicating that using a strong stainless/titanium alloys as screw material is advantageous, and increase in mechanical stability can be achieved by reducing the screw exposure length. Simulation results also revealed that mini-screw and bone surface contact can provide sufficient mechanical retention to perform immediately load in clinical treatment. PMID:20466376

Lin, Chun-Li; Yu, Jian-Hong; Liu, Heng-Liang; Lin, Chih-Hao; Lin, Yang-Sung

2010-08-10

325

Distal type of aortopulmonary window. Report of 4 cases  

Microsoft Academic Search

We have studied 14 patients with aortopulmonary window (10 male and 4 female, age range 1 month to 41 years). Four of these had a distal defect with characteristic haemodynamic and angiographic features. Aortopulmonary window may be classified into 3 types: type I (proximal) defects occur in the proximal part of aortopulmonary septum; type II (distal) defects occur in the

K Mori; M Ando; A Takao; S Ishikawa; Y Imai

1978-01-01

326

Young Children's Sibling Relationship Quality: Distal and Proximal Correlates  

ERIC Educational Resources Information Center

Background: Relationships within families are interdependent and related to distal environmental factors. Low socioeconomic status (SES) and high household chaos (distal factors) have been linked to less positive marital and parent-child relationships, but have not yet been examined with regard to young children's sibling relationships. The…

Kretschmer, Tina; Pike, Alison

2009-01-01

327

Distal neuropathy in spontaneous diabetes mellitus in the dog  

Microsoft Academic Search

Peripheral nerves of three mature dogs with chronic spontaneous diabetes mellitus were examined using qualitative and quantitative techniques. The principal pathologic findings in single-teased fibers were remyelination and axonal regeneration. It is suggested that these changes which occurred in distal plantar nerves but not in more proximal tibial nerves result from a distal axonopathy. The dog may prove to be

K. G. Braund; J. E. Steiss

1982-01-01

328

Incision of recurrent distal esophageal (Schatzki) ring after dilation  

Microsoft Academic Search

Background: Distal esophageal (Schatzki) ring is a frequent cause of dysphagia. Bougienage is generally effective but relapse is common. Outcomes for patients treated by endoscopic incision of distal esophageal rings after symptomatic relapses after bougienage are described. Methods: Eleven patients (2 women, 9 men; median age 61 years; range 24 to 81 years) with recurrent dysphagia after bougienage with large

James A. DiSario; Peder J. Pedersen; Cristina Bichi?-Canoutas; Stephen C. Alder; John C. Fang

2002-01-01

329

Usefulness of autogenous bypass grafts originating distal to the groin  

Microsoft Academic Search

Purpose: Infrainguinal bypass grafting with a proximal anastomosis distal to the groin has been used increasingly to conserve available conduit and reduce wound morbidity and recovery time. The usefulness of the liberalized use of distal origin grafts (DOGs) is unknown. Methods: Consecutive autogenous DOG procedures that were performed between 1978 and 2000 were reviewed retrospectively with a computerized registry. Procedures

Amy B. Reed; Michael S. Conte; Michael Belkin; John A. Mannick; Anthony D. Whittemore; Magruder C. Donaldson

2002-01-01

330

Distal airway dysfunction in obese subjects corrects after bariatric surgery  

Microsoft Academic Search

BackgroundObesity is frequently associated with respiratory symptoms despite normal large airway function as assessed by spirometry. However, reduced functional residual capacity and expiratory reserve volume are common and might reflect distal airway dysfunction. Impulse oscillometry (IOS) might identify distal airway abnormalities not detected using routine spirometry screening. Our objective was to test the hypothesis that excess body weight will result

Beno W. Oppenheimer; Ryan Macht; Roberta M. Goldring; Alexandra Stabile; Kenneth I. Berger; Manish Parikh

331

Technical note: How to spare the pronator quadratus during MIPO of distal radius fractures by using a mini-volar plate.  

PubMed

Few surgical approaches have been described that spare the pronator quadratus (PQ) during the treatment of distal radius fractures. The PQ supplies blood to the distal radial epiphysis, helps stabilize the distal radio-ulnar joint, and contributes 21% of pronation strength. Sparing the PQ should result in faster bone union and shorter recovery time. To achieve these goals, we currently use a minimally-invasive volar procedure using a specially-designed short plate (APTUS Wrist 2.5 XS, Medartis(©)). A 20mm incision is made over the fracture line as described by Henry. The PQ is dissected and then detached from the volar side of the radius. Forceps are used to slide the plate under the muscle. The screws are locked after carefully elevating the distal edge of the PQ. A preliminary study of distal radius fracture fixation by this technique was performed in 31 patients. The scar was 26mm in length and the duration of surgery was 34minutes on average. Patients wore a removable brace for 15 days, and passive wrist motion without loading was allowed during the first week. Functional recovery was faster than seen in previously published series. An average Quick DASH score of 10 was achieved by the 10th post-operative week. Although there are no contraindications to this technique, the quality of the reduction is more important than the scar size and desire to spare the PQ. Never hesitate to convert the incision to a classical Henry approach if technical difficulties arise. Our technique seems best suited to patients with high functional demands. It is currently being evaluated in a prospective series. PMID:24629441

Rey, P-B; Rochet, S; Loisel, F; Obert, L

2014-04-01

332

Surgical Treatment of Extra-articular or Simple Intra-articular Distal Tibial Fractures: MIPO Versus Supercutaneous Plating.  

PubMed

Minimally invasive plate osteosynthesis (MIPO) has become a widely accepted technique to treat distal tibial fractures. Recently, the novel application of a locking plate used as an external fixator (supercutaneous plating) was introduced for the management of open fractures and infected nonunions and even as an adjunct in distraction osteogenesis, which is considered another less invasive method. The aim of this study was to compare the results of supercutaneous plating with closed reduction and minimally invasive plating in the treatment of distal tibial fractures. Forty-eight matched patients were divided according to age, sex, Injury Severity Score, and fracture pattern into the MIPO group and the supercutaneous plating group. Minimum follow-up was 12 months (mean, 18.5 months; range, 12-26 months). No patient had nonunion, hardware breakdown, or deep infection. Patients in the supercutaneous plating group had a significantly shorter mean operative time (65.6±13.2 vs 85.9±14.0 minutes; P=.000), hospital stay (7.5±2.0 vs 13.0±4.4 days; P=.000), and union time (15.2±2.4 vs 17.0±2.8 weeks; P=.000). In the MIPO group, 15 (62.5%) patients reported implant impingement or discomfort and there was 1 incidence of stripping of 15.6% at the time of locking screw removal, whereas in the supercutaneous plating group, no patient reported skin irritation, and removal of the supercutaneous plate was easily performed in clinic without anesthesia. Distal tibial fractures may be treated successfully with MIPO or supercutaneous plating. However, the supercutaneous plating technique may represent a superior surgical option because it offers advantages in terms of mean operative time, hospital stay, and union time; skin irritation; and implant removal. PMID:25275982

He, Xianfeng; Zhang, Jingwei; Li, Ming; Yu, Yihui; Zhu, Limei

2014-09-01

333

Gear-Cutting Tool for Screw-Compressor Rotors  

NASA Astrophysics Data System (ADS)

A built-up hob for a screw-compressor rotor is proposed. The hob is composed of cutter blades and a hob head. The blade is cut out from a tempered planar plate of high speed tool steel by wire-cut electrodischarge machining (EDM). During the wire cutting process, the wire electrode has a fixed angle to ensure both the side and the end relief angle of the cutting edge, so that the rake face regrinding sharpens the cutting edge without changing the profile of the rake face. In other words, theoretically, the hob has no accuracy deterioration due to rake face regrinding. The formulae of rack tooth profile are derived from the female rotor tooth profile experssed by numerical formulae. Next, the fundamental helicoid of the hob the profile of the cutting edge of the blade are calculated. The hob was fabricated and the rotor hobbing was carried out.

Kaneko, Katsumi; Kawasaki, Kazumasa; Tamura, Hisashi

334

Repair of spondylolytic defect with a cable screw reconstruction.  

PubMed

We present the clinical and radiological results of surgical repair for refractory spondylolysis in 20 patients at a minimum follow-up of 2 years. Seventeen of them were reassessed after 5 years. The Oswestry scores revealed good to excellent results in 90% (18/20 patients), indicating a good outcome with surgical repair using two techniques: the Scott procedure or pedicle screw and wire technique. Radiological pseudarthosis was 10%, which was quite consistent with reported series. CT scanning of the 14 patients after a mean of 13 months revealed complete healing of the fracture in 7 patients, partial in 2 and frank non-union in 5. Overall, CT examination with reversed gantry showed only 7/14 (50%) healing, indicating that radiological healing on plain X-ray is not always suggestive of complete bony healing. However, CT healing is not a sine qua non of good to excellent clinical outcome. PMID:17431623

Pai, Vasudeva S; Hodgson, Bruce; Pai, Vishal

2008-02-01

335

[Esthetic results after orthodontic treatment with the CostAnchorage device].  

PubMed

An intrabone screw with a special interlocking for wire insertion is proposed. It can deliver forces in all the three planes of the mouth. In order to produce intrusive and extrusive vectors and various type of dental movement as molar distalizer movement by lingual side approach. The interlocking is inside the screw head and the wire remain free to turn and doesn't produce torsion on the screw. It permits the use of the device also as submerged screw in both intraalveolars areas covered by cheratine gum and extraalveolars area covered by mobile mucosa as fornix. A preliminary report to recovery the aesthetic dento-alveolar records of the smile in "senior-patients" is presented. The "smile lifting" by reposition of upper frontal teeth has been done thanks the force system vector deliver from the intrabone device. PMID:18364214

Costa, Antonio; Fazzari, Antonio

2008-03-01

336

The use of distal rhynchokinesis by birds feeding in water.  

PubMed

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

Estrella, Sora M; Masero, José A

2007-11-01

337

Flow and pressure characteristics within a screw compressor  

NASA Astrophysics Data System (ADS)

The angle-resolved mean and turbulence characteristics of the axial air flow inside a screw compressor with both male and female rotors have been measured, using a laser Doppler velocimeter (LDV) with high spatial and temporal resolution at different radial and axial locations for speeds of 800-1600 rpm, discharge pressures of 1-1.6 bar and discharge temperatures of 33-90°C. The velocity measurements were performed through a special transparent window fixed near the discharge port. The results confirmed the ability of the LDV technique to characterise the flow inside the compressor working chamber; an angular resolution of 1.5° was able to fully describe the velocity field within the machine. The flow variation between the different working chambers was established as well as the spatial variation of the axial mean velocity and turbulence velocity fluctuation within the working chamber. The effect of discharge port opening on the axial mean and RMS velocities was found to be significant near the leading edge of the rotors causing an increase in the mean and RMS velocities of the order of 4.2Vp in mean (where Vp is the axial pitched velocity) for male rotor and 5.4Vp for, female rotor and this effect is less pronounced on the flow near the root of the rotor. Moreover, to obtain a better understanding of the flow motion, a high sampling rate pressure transducer was used to provide the internal angular static pressure variation. These measurements are used to validate the in-house CFD model of the fluid flow within twin screw compressors which, in turn, allows reliable optimisation of various compressor designs.

Guerrato, D.; Nouri, J. M.; Stosic, N.; Arcoumanis, C.

2007-10-01

338

Alkaline twin-screw extrusion pretreatment for fermentable sugar production  

PubMed Central

Background The inevitable depletion of fossil fuels has resulted in an increasing worldwide interest in exploring alternative and sustainable energy sources. Lignocellulose, which is the most abundant biomass on earth, is widely regarded as a promising raw material to produce fuel ethanol. Pretreatment is an essential step to disrupt the recalcitrance of lignocellulosic matrix for enzymatic saccharification and bioethanol production. This paper established an ATSE (alkaline twin-screw extrusion pretreatment) process using a specially designed twin-screw extruder in the presence of alkaline solution to improve the enzymatic hydrolysis efficiency of corn stover for the production of fermentable sugars. Results The ATSE pretreatment was conducted with a biomass/liquid ratio of 1/2 (w/w) at a temperature of 99°C without heating equipment. The results indicated that ATSE pretreatment is effective in improving the enzymatic digestibility of corn stover. Sodium hydroxide loading is more influential factor affecting both sugar yield and lignin degradation than heat preservation time. After ATSE pretreatment under the proper conditions (NaOH loading of 0.06 g/g biomass during ATSE and 1 hour heat preservation after extrusion), 71% lignin removal was achieved and the conversions of glucan and xylan in the pretreated biomass can reach to 83% and 89% respectively via subsequent enzymatic hydrolysis (cellulase loading of 20 FPU/g-biomass and substrate consistency of 2%). About 78% of the original polysaccharides were converted into fermentable sugars. Conclusions With the physicochemical functions in extrusion, the ATSE method can effectively overcome the recalcitrance of lignocellulose for the production of fermentable sugars from corn stover. This process can be considered as a promising pretreatment method due to its relatively low temperature (99°C), high biomass/liquid ratio (1/2) and satisfied total sugar yield (78%), despite further study is needed for process optimization and cost reduction. PMID:23834726

2013-01-01

339

A cementless, elastic press-fit socket with and without screws  

PubMed Central

Background The acetabular component has remained the weakest link in hip arthroplasty regarding achievement of long-term survival. Primary fixation is a prerequisite for long-term performance. For this reason, we investigated the stability of a unique cementless titanium-coated elastic monoblock socket and the influence of supplementary screw fixation. Patient and methods During 2006–2008, we performed a randomized controlled trial on 37 patients (mean age 63 years (SD 7), 22 females) in whom we implanted a cementless press-fit socket. The socket was implanted with additional screw fixation (group A, n = 19) and without additional screw fixation (group B, n = 18). Using radiostereometric analysis with a 2-year follow-up, we determined the stability of the socket. Clinically relevant migration was defined as > 1 mm translation and > 2º rotation. Clinical scores were determined. Results The sockets without screw fixation showed a statistically significantly higher proximal translation compared to the socket with additional screw fixation. However, this higher migration was below the clinically relevant threshold. The numbers of migratory sockets were not significantly different between groups. After the 2-year follow-up, there were no clinically relevant differences between groups A and B regarding the clinical scores. 1 patient dropped out of the study. In the others, no sockets were revised. Interpretation We found that additional screw fixation is not necessary to achieve stability of the cementless press-fit elastic RM socket. We saw no postoperative benefit or clinical effect of additional screw fixation. PMID:23083434

2012-01-01

340

An investigation of the effects of hydroxyapatite coatings on the fixation strength of cortical screws.  

PubMed

Hydroxyapatite (HA) are commonly applied to orthopaedic implants for acceleration of osteointegration and so overcoming the loosening problems such as in cortical screws. Electrophoretic deposition (EPD) of hydroxyapatite was applied for coating of cortical screws in this work. The effects of hydroxyapatite-coated and uncoated cortical screws on insertion and extraction torque were investigated through in vivo experiments. Three groups of screws were undertaken: first group with no coating, second group coated with HA and the third group coated with HA+interlayer, a synthetic calcium silicate compound. Five sheep were operated, and 60 cortical (20 x 3) screws from those of groups were implanted in cortical femurs to observe the effect of HA and interlayer on screws. Results show that as an alternative to plasma spray coating method, the EPD process enables to produce a quick, easy, cheap and uniform adjustable coating layer. Also from biomechanical and SEM examinations, HA coating by EPD method of cortical screws resulted in extremely improved fixation with reduced risk of loosening problem. PMID:15694605

Yildirim, O S; Aksakal, B; Celik, H; Vangolu, Y; Okur, A

2005-04-01

341

Effect of bone mineral density and amorphous diamond coatings on insertion torque of bone screws.  

PubMed

In this study, the potential of high-quality amorphous diamond (AD) coatings in reducing the torque and failures of bone screws was studied. Torque values were recorded for 32 stainless steel screws, 2.7 or 3.5 mm in diameter and 60 mm in length. Half of the screw sets were coated with the AD coating before installing in predrilled holes of human cadaveric femoral bone samples. The bone samples were selected from two groups of four persons with mean ages of 34 years (range 25-41 years) and 75 years (range 73-77 years), respectively. The bone mineral density (BMD) values of the samples were determined exactly at the screw insertion site by peripheral quantitative computed tomography (pQCT). In the mechanical tests, insertion and removal torques were measured. BMD had a significant effect on insertion torque; the maximum torque (adjusted with respect to the screw diameter) was significantly higher for the young bone than for the old bone (p < 0.05). By using a polished AD coating, insertion torque was decreased even up to 50% in comparison with the screws without coating. The results suggest that AD coating provides a stable, smooth surface and reduces the risk of screw failures. PMID:15878374

Koistinen, Arto; Santavirta, Seppo S; Kröger, Heikki; Lappalainen, Reijo

2005-10-01

342

Ca2+-sensors and ROS-GC: interlocked sensory transduction elements: a review  

PubMed Central

From its initial discovery that ROS-GC membrane guanylate cyclase is a mono-modal Ca2+-transduction system linked exclusively with the photo-transduction machinery to the successive finding that it embodies a remarkable bimodal Ca2+ signaling device, its widened transduction role in the general signaling mechanisms of the sensory neuron cells was envisioned. A theoretical concept was proposed where Ca2+-modulates ROS-GC through its generated cyclic GMP via a nearby cyclic nucleotide gated channel and creates a hyper- or depolarized sate in the neuron membrane (Ca2+ Binding Proteins 1:1, 7–11, 2006). The generated electric potential then becomes a mode of transmission of the parent [Ca2+]i signal. Ca2+ and ROS-GC are interlocked messengers in multiple sensory transduction mechanisms. This comprehensive review discusses the developmental stages to the present status of this concept and demonstrates how neuronal Ca2+-sensor (NCS) proteins are the interconnected elements of this elegant ROS-GC transduction system. The focus is on the dynamism of the structural composition of this system, and how it accommodates selectivity and elasticity for the Ca2+ signals to perform multiple tasks linked with the SENSES of vision, smell, and possibly of taste and the pineal gland. An intriguing illustration is provided for the Ca2+ sensor GCAP1 which displays its remarkable ability for its flexibility in function from being a photoreceptor sensor to an odorant receptor sensor. In doing so it reverses its function from an inhibitor of ROS-GC to the stimulator of ONE-GC membrane guanylate cyclase. PMID:22509149

Sharma, Rameshwar K.; Duda, Teresa

2012-01-01

343

Navigated pedicle screw placement using computed tomographic data in dorsolumbar fractures  

PubMed Central

Background: Computed tomographic (CT) based navigation is a technique to improve the accuracy of pedicle screw placement. It is believed to enhance accuracy of pedicle screw placement, potentially avoiding complications arising due to pedicle wall breach. This study aims to assess the results of dorsolumbar fractures operated by this technique. Materials and Methods: Thirty consecutive skeletally mature patients of fractures of dorsolumbar spine (T9–L5) were subjected to an optoelectronic navigation system. All patients were thoroughly examined for neurological deficit. The criterion for instability were either a tricolumnar injury or presence of neurological deficit or both. Patients with multilevel fractures and distorted spine were excluded from study. Time taken for insertion of each pedicle screw was recorded and placement assessed with a postoperative CT scan using Laine's grading system. Results: Only one screw out of a total of 118 screws was misplaced with a Laine's Grade 5 placement, showing a misplacement rate of 0.847%. Average time for matching was 7.8 min (range 5-12 min). Average time taken for insertion of a single screw was 4.19 min (range 2-8 min) and total time for all screws after exposure was 34.23 min (range 24-45 min) for a four screw construct. No neurovascular complications were seen in any of the patients postoperatively and in subsequent followup of 1-year duration. Conclusion: CT-based navigation is effective in improving accuracy of pedicle screw placement in traumatic injuries of dorsolumbar spine (T9-L5), however additional cost of procuring CT scan to the patient and cost of equipment is of significant concern in developing countries. Reduced radiation exposure and lowered ergonomic constraints around the operation table are its additional benefits.

Kapoor, Saurabh; Sharma, Rajbahadur; Garg, Sudhir; Jindal, Rohit; Gupta, Ravi; Goe, Anshul

2014-01-01

344

An anomalous bifid distal ulna: A case report?  

PubMed Central

INTRODUCTION We report a case of an osteochondroma in the form of an anomalous bifid distal ulna following mal-union of an epiphyseal injury. There has been no previous case of this reported in the medical literature. PRESENTATION OF CASE A 19-year-old man presented with wrist stiffness and complete loss of pronation and supination twelve months after having undergone open reduction and internal fixation for a volarly displaced distal radius fracture. Further investigation with a CT scan showed a bifid distal ulna. As this was not present on plain radiographs one year prior, it was proposed that this was an osteochrondromatous growth caused by injury to the distal ulnar epiphysis. An operation was performed to excise one of the distal ulna heads, and reconstruct the TFCC to allow improved rotational movements. At one year follow-up, the patient has made an almost full recovery without complication. DISCUSSION We postulate that the patient sustained an occult physeal injury resulting in an osteochondromatous lesion that grew towards the joint effectively forming a second ulna head. CONCLUSION This is a unique case of the development of a bifid distal ulna due to physeal injury one year prior. Such a lesion has not previously been described in the distal ulna. PMID:24055912

Jones, C.; Li, H.; Ellahee, N.

2013-01-01

345

Screw-rotation twinning through helical movement of triple-partials  

NASA Astrophysics Data System (ADS)

By in situ uniaxial-tensile tests with dynamic and atomic scale observation, we report the quantitative investigation of strain-induced deformation-twinning process through incoherent twin boundary propagation in nanocrystalline Au. The consecutive and quantitative strain maps revealed that a strong compressive strain, up to 5.8%, was formed. A screw-rotation twinning mechanism by consecutive and collective screw-rotations of triple-partials along a [111] screw-axis is proposed. This twin generates a macro-strain of 0.707, same as the conventional shear twins, but in a helical manner.

Liu, Pan; Du, Kui; Zhang, Jianxin; Wang, Lihua; Yue, Yonghai; Ma, Evan; Zhang, Yuefei; Zhang, Ze; Chen, Mingwei; Han, Xiaodong

2012-09-01

346

Sapphire screws and strength test on them at liquid nitrogen temperature  

NASA Astrophysics Data System (ADS)

We fabricated several sapphire screw threads and performed a strength test on them at the liquid nitrogen temperature of 77 K. The screw threads were subjected to and withstood a 3000 N load. To the best of our knowledge, this is the first strength test of sapphire screw threads at a cryogenic temperature. The result suggests a new way of connecting sapphire components. Although sapphire is already used in many applications, the result may provide a new way to use the material as a structural element in even more applications.

Hirose, Eiichi; Sakakibara, Yusuke; Igarashi, Yukihiko; Ishii, Takashi

2014-10-01

347

Four-Screw Plate Fixation vs Conventional Fixation for Diaphyseal Fractures of the Forearm  

PubMed Central

Background: Standard treatment of diaphyseal fractures of the forearm is open reduction and fixation using dynamic compression plates (DCP) and screws. This technique uses screw placement in all 6 or more of the plate holes except the hole over the fracture line. We hypothesized that DCP with selective 4-screw bicortical placement can provide adequate fixation for these fractures. Objectives: The aim of this study was to evaluate the results of conventional 6 or more screw fixation versus 4 screw fixation for adults with diaphyseal fractures of the forearm. Patients and Methods: In this prospective study, 128 fractures of the ulna, radius or both bones of the forearm in 87 patients were treated in either one of these two groups: Open reduction and internal fixation (ORIF) with conventional DCP and screws or ORIF using DCP and selective 4- screw placement. Fractures were transverse or oblique in pattern without gross comminution. In a total of 41 patients with fractures, 28 single ulnar and 18 single radius fractures were included. Follow-up visits were done at 3-6 and 12-16 weeks and at 6 months. Outcome with respect to union an nonunion rates, union time, infection, and device failure was noted. Results: No change in alignment was noted in any patient. Union time in conventional and selective bicortical 4-screw fixation was 74.8 days and 73.6 days respectively which showed no significant difference (P = 0.064). Union rate and infection was 92.1% and 3.2% in conventional and 95.3% and 0% in the selective group respectively. Non-union was observed in 5 and 3 cases of fractures in conventional and the selective group respectively. Conclusions: For treatment of the transverse or oblique diaphyseal fractures of the forearm, fixation by a same length 3.5 mm DCP with selective 4-screw cortical fixation (2 screws on each side of the fracture site) had similar results in comparison with conventional 6 or more DCP screws. Because of lesser impact on host bone and smaller incision, the selective 4-screw insertion can be an alternative technique for treatment of these fractures. PMID:24829892

Mehdi Nasab, Seyed Abdolhossein; Sarrafan, Nasser; Sabahi, Saeed

2012-01-01

348

Less is more: lag screw only fixation of lateral malleolar fractures  

PubMed Central

Displaced fractures of the lateral malleolus are typically treated with plate osteosynthesis with or without the use of lag screws, and immobilisation in a plaster cast for up to 6 weeks. Fixation through a smaller incision with less metal, such as lag screw only fixation, would theoretically lead to decreased infection rates and less irritation caused by hardware. The purpose of this study was to evaluate the benefits and success of lag screw only fixation of the lateral malleolus in non-comminuted oblique fractures of the lateral malleolus. A total of 25 patients who had non-comminuted unstable oblique fractures of their lateral malleolus that had been surgically fixed with lag screws only were retrospectively evaluated. All patients were younger than 60 years of age. Evaluation of the success of fixation, complications, resultant mobility and patient satisfaction was based on information gathered from chart reviews, X-ray findings and a standardised questionnaire based on the AOFAS Foot and Ankle Outcomes Questionnaire. These results were compared to an age-matched group of 25 consecutive patients treated with plate osteosynthesis. Of the 25 patients fixed with lag screws, nine had an unstable fracture of the lateral malleolus only, ten were bimalleolar fractures and six were trimalleolar. Eighteen patients were treated with two lag screws, and seven were treated with three lag screws. The bi- and trimalleolar fractures were treated with standard partially threaded cancellous screws. None of the lag screw-only group lost reduction. There were no documented wound infections in the lag screw group as compared to three deep infections in the plate group. Lag screw-only patients reported no palpable hardware as compared to 50% of the plate group. AOFAS scores at a mean of 12 months post-operative were similar in both groups. Lag screw only fixation of the lateral malleolus is a safe and effective method that has a number of advantages over plate osteosynthesis, in particular less soft tissue dissection, less prominent, symptomatic and palpable hardware and a reduced requirement for secondary surgical removal. PMID:16947052

O'Shea, Kieran; Burke, Tom

2006-01-01

349

Posterior pelvic ring fractures: Closed reduction and percutaneous CT-guided sacroiliac screw fixation  

Microsoft Academic Search

Purpose  To assess the midterm results of closed reduction and percutaneous fixation (CRPF) with computed tomography (CT)-guided sacroiliac\\u000a screw fixation in longitudinal posterior pelvic ring fractures.\\u000a \\u000a \\u000a \\u000a Methods  Thirteen patients with 15 fractures were treated. Eleven patients received a unilateral, two a bilateral, screw fixation.\\u000a Twenty-seven screws were implanted. Continuous on-table traction was used in six cases. Mean radiological follow-up was 13\\u000a months.

Augustinus Ludwig Jacob; Peter Messmer; Klaus-Wilhelm Stock; Norbert Suhm; Bernard Baumann; Pietro Regazzoni; Wolfgang Steinbrich

1997-01-01

350

SPECT-CT Assessment of Pseudarthrosis after Spinal Fusion: Diagnostic Pitfall due to a Broken Screw  

PubMed Central

A 43-year-old drug addicted female was referred for a L5-S1 posterolateral in situ fixation with autologous graft because of an L5/S1 severe discopathy with listhesis. After six months, low back pain recurred. A Tc-99m HDP SPECT-CT diagnosed a pseudarthrosis with intense uptake of the L5-S1 endplates and a fracture of the right S1 screw just outside the metal-bone interface without any uptake or bone resorption around the screw. The absence of uptake around a broken screw is a pitfall that the physician should be aware of. PMID:24159394

Rager, Olivier; Amzalag, Gael; Varoquaux, Arthur; Schaller, Karl; Ratib, Osman; Tessitore, Enrico

2013-01-01

351

Monoaxial Pedicle Screws Are Superior to Polyaxial Pedicle Screws and the Two Pin External Fixator for Subcutaneous Anterior Pelvic Fixation in a Biomechanical Analysis  

PubMed Central

Purpose. Comparison of monoaxial and polyaxial screws with the use of subcutaneous anterior pelvic fixation. Methods. Four different groups each having 5 constructs were tested in distraction within the elastic range. Once that was completed, 3 components were tested in torsion within the elastic range, 2 to torsional failure and 3 in distraction until failure. Results. The pedicle screw systems showed higher stiffness (4.008 ± 0.113?Nmm monoaxial, 3.638 ± 0.108?Nmm Click-x; 3.634 ± 0.147?Nmm Pangea) than the exfix system (2.882 ± 0.054?Nmm) in distraction. In failure testing, monoaxial pedicle screw system was stronger (360?N) than exfixes (160?N) and polyaxial devices which failed if distracted greater than 4?cm (157?N Click-x or 138?N Pangea). The exfix had higher peak torque and torsional stiffness than all pedicle systems. In torsion, the yield strengths were the same for all constructs. Conclusion. The infix device constructed with polyaxial or monoaxial pedicle screws is stiffer than the 2 pin external fixator in distraction testing. In extreme cases, the use of reinforcement or monoaxial systems which do not fail even at 360?N is a better option. In torsional testing, the 2 pin external fixator is stiffer than the pedicle screw systems. PMID:24368943

Vaidya, Rahul; Onwudiwe, Ndidi; Roth, Matthew; Sethi, Anil

2013-01-01

352

Potassium transport across guinea pig distal colon  

SciTech Connect

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.

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

1986-03-05

353

Crohn's disease of the distal ileum.  

PubMed Central

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

Higgens, C S; Allan, R N

1980-01-01

354

Distal clavicular osteolysis: MR evidence for subchondral fracture  

Microsoft Academic Search

Purpose  To investigate the association between distal clavicular osteolysis and subchondral fractures of the distal clavicle at MRI.\\u000a \\u000a \\u000a \\u000a Materials and methods  This study was approved by the hospital human research committee, which waived the need for informed consent. Three radiologists\\u000a retrospectively analyzed 36 shoulder MR examinations in 36 patients with imaging findings of distal clavicular osteolysis.\\u000a The presence of a subchondral fracture

Ara Kassarjian; Eva Llopis; William E. Palmer

2007-01-01

355

The Evolution of Distal Radius Fracture Management - A Historical Treatise  

PubMed Central

Distal radius fractures have been a common affliction for millennia, but their treatment is a more recent development as a result of human erudition. While immobilization has served as the only available treatment for most of our history, many advances have been made in the management of distal radius fractures over the last century as the field of orthopedics has grown. Yet, the topic remains hotly contested in the literature, and research continues to focus upon it given the frequency of the injury. In this article, we chronicle the evolution of distal radius fracture treatment in hopes of providing context for the future that lies ahead. PMID:22554653

Diaz-Garcia, Rafael J.; Chung, Kevin C.

2012-01-01

356

An Asian Perspective on the Management of Distal Radius Fractures  

PubMed Central

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

Sebastin, Sandeep J.; Chung, Kevin C.

2012-01-01

357

Analysis of stress induced by screws in the vertebral fixation system  

PubMed Central

Objective: To compare, using photoelasticity, internal stress produced by USS II type screw with 5.2 and 6.2 mm external diameters, when submitted to three different pullout strengths. Methods: Two photoelastic models were especially made. The simulation was performed using loads of 1.8, 2.4 e 3.3 kgf.The fringe orders were evaluated around the screws. In all the models analyzed the shear stress were calculated. Results: Independently of the applied load, the smaller screw showed higher values of shear stress. Conclusion: According to the analysis performed, we observed that the place of highest stress was in the first thread of the lead, close to the head of the screws. Experimental study. PMID:24644414

Fakhouri, Sarah Fakher; Shimano, Marcos Massao; de Araujo, Cleudmar Amaral; Defino, Helton Luiz Aparecido; Shimano, Antonio Carlos

2014-01-01

358

Three point lead screw positioning apparatus for a cavity tuning plate  

NASA Technical Reports Server (NTRS)

Three lead screws are provided for adjusting the position of a traversing plate. Each of the three lead screws is threaded through a collar that is press fitted through the center of one of three pinion gears. A sun gear meshes with all three pinion gears and transversely moves the three lead screws upon actuation of a drive gear. The drive gear meshes with the sun gear and is driven by a handle or servomotor. When the handle or servomotor rotates the drive gear, the sun gear rotates causing the three pinion gears to rotate, thus, causing transverse movement of the three lead screws and, accordingly, transverse movement of the transversing plate. When the drive gear rotates, the traversing plate is driven in and out of a microwave cavity. Thus, the length or size of the cavity can be tuned while maintaining the traversing plate in an exact parallel relationship with an opposing plate on another end of the cavity.

Calco, Frank S. (inventor)

1993-01-01

359

Mechanically Working Fully-Automatic Plant for the Regeneration of Used Aluminum Cap Screws for Bottles.  

National Technical Information Service (NTIS)

A mechanical separation process for used aluminum cap screws for bottles is described. A prototype separation plant was developed and constructed. Test results indicate low energy consumption, no water pollution, and no emission of noxious vapors.

V. Schach, H. Schach

1983-01-01

360

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

...SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Tools-Hand and Power § 1926.305 Jacks—lever and ratchet, screw, and hydraulic. (a) General requirements. (1)...

2014-07-01

361

Modeling of wet gas compression in twin-screw multiphase pump  

E-print Network

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...

Xu, Jian

2009-05-15

362

Intermaxillary fixation screw for endotracheal tube fixation in the edentulous patient with facial burns.  

PubMed

Endotracheal tube fixation in patients with severe facial burns and edentulism is a challenge. We describe a simple and elegant method to secure the endotracheal tube in such patients by means of an intermaxillary fixation screw. PMID:24948409

Fleissig, Y; Rushinek, H; Regev, E

2014-10-01

363

Screw implantation in the globe: the risk of delayed hardware migration from craniofacial repair.  

PubMed

Plating system modification has enabled the use of rigid fixation in younger patients having maxillofacial surgery. One of the common reported complications of the use of plates and screws in children is screw migration due to skeletal maturation. Ophthalmic complications due to maxillofacial surgery reported to date include oculomotor and abducens palsies, lacrimal damage and vision loss due to infection, retrobulbar hemorrhage, and compartment syndrome. We describe a complication unique to screw migration resulting in orbital fixation and near-globe rupture in a patient with Treacher Collins syndrome. We hope to alert our colleagues to the potential risk of screw and hardware migration and breakage, particularly in the setting of craniofacial surgery performed on a child before maturation of craniofacial osseous structures. PMID:24036744

Sadiq, Mohammad Ali A; Prabhu, Sanjay P; Fearon, Jeffrey A; Taghinia, Amir H; Dagi, Linda R

2013-09-01

364

The phrenic ampulla: distal esophagus or potential hiatal hernia?  

E-print Network

The phrenic ampulla: distal esophagus or potential hiatal hernia? SHEZHANG LIN, JAMES G. BRASSEUR, University Park, Pennsylvania 16802 Lin, Shezhang, James G. Brasseur, Philippe Pouder- oux, and Peter J

Brasseur, James G.

365

Genetics Home Reference: Distal hereditary motor neuropathy, type II  

MedlinePLUS

... role in the tensing of muscle fibers (muscle contraction). Heat shock protein beta-1 and heat shock ... atrophy ; autosomal ; autosomal dominant ; axons ; big toe ; cell ; contraction ; cytoskeleton ; diameter ; distal ; gene ; hereditary ; infection ; inflammation ; inherited ; ...

366

Stress fractures of the distal radius in adolescent gymnasts  

Microsoft Academic Search

Adolescent girl gymnasts sustained stress fractures of the distal end of the radius in the wrist on which a rotational vault was performed. The history and clinical progress were typical of stress fractures.

M. T. F. Read

1981-01-01

367

Genetics Home Reference: Distal hereditary motor neuropathy, type V  

MedlinePLUS

... indicate that misfolded seipin proteins accumulate in the endoplasmic reticulum, which is a structure inside the cell that ... type V? atrophy ; autosomal ; autosomal dominant ; cell ; distal ; endoplasmic reticulum ; enzyme ; gait ; gene ; hereditary ; incidence ; inherited ; motor ; neuropathy ; ...

368

Biomechanical measurements of cortical screw purchase in five types of human and artificial humeri.  

PubMed

Humerus shaft fracture fixation is largely dependent on cortical screw purchase in host bone. Only 2 prior studies assessed cortical screw purchase in human humeral shafts, but were of very limited scope and did not fully assess humerus material properties. Also, no studies evaluated the human dried or artificial humeri both commercially available from Sawbones. Vashon, WA, USA. Therefore, present authors measured cortical screw purchase in human fresh-frozen (FF) (n=19), human embalmed (EM) (n=18), human dried (DR) (n=14), artificial "normal" (AN) (n=13), and artificial "osteoporotic" (AO) (n=13) humeri. Each humerus had 2 bicortical screws of 3.5-mm diameter inserted 20mm apart through the shaft's anterior and posterior cortices. Absolute force, displacement, and energy for screw-bone interface failure were measured by screw pullout tests, afterwhich data were normalized by total surface area engaged at the screw-bone interface. For absolute force, AN humeri reached a higher load than EM (p=0.001) and AO (p<0.001) humeri, whilst AN humeri achieved lower normalized force than DR humeri (p=0.018). For absolute displacement, AO humeri achieved a lower level than FF humeri (p=0.013), whilst for normalized displacement AN humeri had lower levels than all other groups (p?0.005) and AO humeri had lower values than EM humeri (p=0.029). For absolute and normalized energy, there were no statistical differences (p?0.066). Human bone mineral density (BMD) ranged from 0.7 to 1.8g/cm(2) and was linearly correlated to screw pullout parameters in 14 of 18 cases (R=0.61 to 0.96), whilst humerus age was not. Consequently, it is recommended that human fresh-frozen, human embalmed, and human dried humeri can be used interchangeably for cortical screw purchase, since they were statistically equivalent for all comparisons. However, artificial humeri were involved in all statistical differences observed and, thus, may not replicate cortical screw purchase in human humeri. To date, this is the most comprehensive study on cortical screw purchase in human and artificial humeral shafts. PMID:24295967

Aziz, Mina S R; Nicayenzi, Bruce; Crookshank, Meghan C; Bougherara, Habiba; Schemitsch, Emil H; Zdero, Radovan

2014-02-01

369

Active potassium absorption in rat distal colon.  

PubMed Central

1. Active potassium (K+) absorption in rat distal colon was investigated by measuring mucosal-to-serosal (JK, ms) and serosal-to-mucosal (JK, sm) 42K+ fluxes (mu equiv h-1 cm-2) across isolated stripped mucosa under short-circuit conditions in normal and dietary Na-depleted animals. As previously demonstrated, removal of Na+ from both mucosal and serosal solutions bathing the normal colon slightly increased net K+ absorption as a result of inhibition of JK, sm without affecting JK, ms, while in the Na-depleted group net K+ secretion (-0.54 +/- 0.11) was converted to a marked net K+ absorption (1.68 +/- 0.30, P less than 0.001). 2. In both groups of animals in Na(+)-free Ringer solution, JK, ms exhibited saturable and linear components, while JK, sm was a linear function of [K+]. Estimated affinity constants (mM) for saturable net K+ absorption were similar in normal (0.52 +/- 0.12) and Na-depleted (0.67 +/- 0.11) animals; however, there was a greater than 3-fold increase in the saturable flux (Jmax) from 0.54 +/- 0.04 in the normal colon to 1.78 +/- 0.08 mu equiv h-1 cm-2 in Na-depleted animals. 3. Mucosal orthovanadate (100 microM) inhibited JK, ms in both normal (control, 0.66 +/- 0.05 vs. orthovanadate, 0.36 +/- 0.03 mu equiv h-1 cm-2, P less than 0.001) and Na-depleted animals (control 1.20 +/- 0.13 vs. orthovanadate 0.77 +/- 0.07 mu equiv h-1 cm-2, P less than 0.01) without affecting JK, sm or the short-circuit current. In the Na-depleted group mucosal omeprazole or SCH28080 (100 microM), inhibitors of gastric K(+)-H(+)-ATPase, insignificantly or slightly reduced (by 10%) JK, ms respectively; in contrast, mucosal ouabain (1 mM) markedly inhibited JK, ms (control, 1.61 +/- 0.16 vs. ouabain, 0.83 +/- 0.98 mu equiv h-1 cm-2, P less than 0.001). 4. Mucosal Na+ appeared to be a competitor of K+ uptake across the apical membrane. 5. These results indicate that dietary Na-depletion increases electroneutral K+ absorption by increasing its transport capacity and suggest that the mechanism of this active K+ absorption process may involve an apical K(+)-ATPase with properties that are unlike the gastric K(+)-H(+)-ATPase but similar, in part, to Na(+)-K(+)-ATPase. PMID:2143781

Sweiry, J H; Binder, H J

1990-01-01

370

I: Hydrodynamic-focusing microreactor II: Mechanically interlocked molecules for functional materials  

NASA Astrophysics Data System (ADS)

I: Microreactors, a class of microfluidics, offer numerous benefits -- such as small sample requirement, short analysis times and automations -- and have been used to study reactions of chemical and biological reagents. In order to understand the relationship between fast mixing, product regioselectivity, as well as the ability to separate, in time and space, the nanoparticle (NP) formation stages, a microreactor capable of fast and controllable mixing was developed (Chapter 1) based on multi-lamination and hydrodynamic-focusing. By taking advantage of the fast and controllable mixing properties of this novel microreactor one can control the time when chemical reactions commence inside the microchannels. These properties of the microreactor can be exploited to improve the product regioselectivity of a diazo-coupling reaction to attain a product distribution of monoazo to diazo product of ˜1:99, a selectivity unprecedented in both conventional, macroscopic reactors and other microfluidic systems. Additionally, the ability to separate different stages during the NP formation process inside the microreactor, allowed us to study the aggregation of polypyrrole NPs. II: Supramolecular actuators and molecular interlocked molecules, such as catenanes and rotaxanes, have attracted considerable attention because of their sophisticated topology and their application in functional molecular devices. The blending of supramolecular and mechanostereochemistry with mesoporous silica NPs has proven to be a powerful combination, leading to the development of a new class of materials -- mechanized silica nanoparticles ( Chapter 2). These new hybrid materials are designed to release their content in response to an external stimuli and their development is being driven by the need to improve current drug delivery technologies. In an effort to explore how the stimuli-controlled mechanical movement of switchable, bistable [2]rotaxanes -- based on a cyclobis(paraquat-p-phenylene) ring, tetrathiafulvalene and 1,5-dioxynapthalene as the recognition units -- can be exploited to develop new electro-optical liquid crystalline (LC) materials, a novel cholesteric LC bistable [2]rotaxane has been designed (Chapter 3) and its synthesis is underway. Furthermore, the electrochromic behavior of Smectic A LC bistable Rlrotaxanes has been accomplished (Chapter 4) in the condensed LC state as well as within a PMMA polymer matrix.

Coti, Karla Karina

371

Analytical and computational modeling of the mechanical interlocking between steel/FRP reinforcing bars and concrete  

NASA Astrophysics Data System (ADS)

Mechanical interaction (commonly called bond) between concrete and reinforcing bars significantly affects the structural response of reinforced concrete. This study addresses modeling issues for the bond of steel and fiber-reinforced polymer---FRP bars. Two analysis scales are examined: the rib-scale (where the surface structure of the bar is often explicitly modeled) and the bar-scale (where the surface is idealized as smooth and an interface idealization is adopted). The study's main objective is to better understand how contact between concrete and a bar with a fabricated surface structure affects the radial elastic response and how these effects can be incorporated into bar-scale models. A limited modeling study on the local crushing near the ribs of a bar is also presented. Experimental or analytical justifications for the radial elastic modulus (D?e) of a barscale model do not exist, yet D? e is important toward predicting bond behavior and splitting failures. A proposed analytical framework defines D?e as characterizing the local elastic deformation resulting from mechanical interlocking. The approach enforces static and strain energy equivalencies of riband bar-scale idealizations. Assuming axisymmetric elastic behavior, homogeneous materials, and periodicity, closed-form analytical solutions are obtained for D? e. D?e's dependence on interface traction distribution, material constants and bar geometry is studied for steel and FRP bars. D? e increases with the contact area but remains finite for full contact (assuming a nonuniform traction). For FRP bars, D?e reproduces the radial snap-back behavior that occurs with longitudinal cracking, which helps explain the splitting behavior of some test specimens and the convergence problems in some numerical studies. For a steel bar D?e is incorporated into a bar-scale bond model via a local contact model which leads to improved prediction of the radial response. Elastoplastic constitutive relations are adopted and implemented in a rib-scale analysis to simulate the local crushing behavior near the surface structure of a bar. Numerical examples show how the crushing is concentrated near the surface structure. For a given axial load, crushing is predicted to decrease with an increase in the level of specimen confinement stress due to frictional response along the remainder of the interface.

Yu, Hailing

372

Neonatal physeal separation of distal humerus during cesarean section.  

PubMed

Diagnosing physeal separation of the distal humerus in a newborn can be challenging. Skeletal immaturity and absence of secondary ossification centers make radiographic diagnosis difficult for inexperienced providers. This fracture is seen in the setting of complicated deliveries with excessive traction and rotation applied to the forearm. We report a case of physeal separation of the distal humerus in a newborn as a complication of cesarean section and describe the intervention used and the short-term results. PMID:25379758

Kamaci, Saygin; Danisman, Murat; Marangoz, Salih

2014-11-01

373

A distal airway foreign body removed with electromagnetic navigation bronchoscopy.  

PubMed

Distal airway foreign bodies can be challenging to remove with a flexible bronchoscope because of angulation or deep impaction. Thoracic surgery may be required if bronchoscopy is not successful. The use of electromagnetic navigation for pulmonary nodule localization and characterization is well established; however, its use to localize and remove distal foreign bodies has not been described. We report the initial case of electromagnetic navigation-assisted foreign body removal. PMID:24739695

Karpman, Craig; Midthun, David E; Mullon, John J

2014-04-01

374

Osteolysis of the distal clavicle in the overhead athlete  

Microsoft Academic Search

Atraumatic osteolysis of the distal clavicle (AODC) is a painful stress overload syndrome of the distal clavicle. Early AODC research basically concentrated on primary weight-lifters (PWL). A review of the literature shows that this condition has been infrequently described in throwing athletes who were adjunct weight-lifters (AWL). Adjunct weight-lifters train with heavy resistance in addition to their sport-specific conditioning program.

Keith R. Pitchford; Bernard R. Cahill

1997-01-01

375

Distal tibia fractures: management and complications of 101 cases  

Microsoft Academic Search

Distal tibia fractures are complex injuries with a high complication rate. In this retrospective and multicentre study we\\u000a attempted to detail complications and outcomes of this type of injury in order to determine predictive factors of poor results.\\u000a Between 2002 and 2004, 104 patients were admitted for 105 distal tibia fractures. One hundred patients (101 fractures) were\\u000a reviewed with an

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

2010-01-01

376

Novel DYSF mutations in Thai patients with distal myopathy  

Microsoft Academic Search

Dysferlinopathy refers to a variety of autosomal recessive, skeletal muscle disorders due to the mutations of dysferlin-encoding gene, DYSF. It encompasses limb-girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy (MM), distal myopathy with anterior tibial onset (DMAT), isolated hyperCKemia, rigid spine syndrome and congenital muscular dystrophy. Herein, we report five Thai patients with distal myopathy due to dysferlinopathy including four

Teerin Liewluck; Sunsanee Pongpakdee; Rawiphan Witoonpanich; Tumtip Sangruchi; Theeraphong Pho-iam; Chanin Limwongse; Wanna Thongnoppakhun; Kanokwan Boonyapisit; Varisa Sopassathit; Suchart Phudhichareonrat; Udom Suthiponpaisan; Natte Raksadawan; Kanako Goto; Yukiko K. Hayashi; Ichizo Nishino

2009-01-01

377

Megaprosthesis versus Condyle-sparing Intercalary Allograft: Distal Femoral Sarcoma  

Microsoft Academic Search

Although functionally appealing in preserving the native knee, the condyle-sparing intercalary allograft of the distal femur\\u000a may be associated with a higher risk of tumor recurrence and endoprosthetic replacement for malignant distal femoral bone\\u000a tumors. We therefore compared the risk of local tumor recurrence between patients in these two types of reconstruction groups.\\u000a We retrospectively reviewed 85 patients (mean age,

Melissa N. Zimel; Amy M. Cizik; Timothy B. Rapp; Jason S. Weisstein; Ernest U. Conrad III

2009-01-01

378

Distal Percutaneous Transluminal Angioplasty Through Infrainguinal Bypass Grafts  

Microsoft Academic Search

Aim: to evaluate the results of transluminal angioplasty (PTA) performed through infrainguinal bypass grafts for stenotic or occlusive lesions at the distal anastomosis and\\/or in the runoff arteries. Design: retrospective clinical study. Material and methods: forty-one patients underwent 57 procedures at the distal anastomosis (n=13), in the runoff arteries (n=32) or at both locations (n=12) at a median of 9.6

A.-M Löfberg; S Karacagil; C Ljungman; R Nyman; A Tulga Ulus; A Boström; G Östholm

2002-01-01

379

Design and Construction of a High Pressure System for Evaluating Multiphase Twin-Screw Pumps  

E-print Network

DESIGN AND CONSTRUCTION OF A HIGH PRESSURE SYSTEM FOR EVALUATING MULTIPHASE TWIN-SCREW PUMPS A Thesis by THEODORE ISAAC HATCH Submitted to the Office of Graduate and Professional Studies of Texas A&M University in partial fulfillment... 2013 Theodore Isaac Hatch ABSTRACT Twin-screw pumps are currently sold by manufacturers without adequate data predicting the pump behavior when pumping multiphase mixtures. In light of the fact that pump behavior is known to change...

Hatch, Theodore Isaac

2013-08-26

380

High viscous liquids as a source in micro-screw heat exchanger: fabrication, simulation and experiments  

Microsoft Academic Search

Viscous liquids can be encountered in many applications of micro devices. In this paper, an experimental and numerical simulation\\u000a of a micro screw concentric tube heat exchanger is presented to determine the overall heat transfer coefficient and the amount\\u000a of heat created by friction. The screw surface area and the increase in the viscosity of the liquid can raise the

Haifa El-Sadi; Nabil Esmail; Andreas K. Athienitis

2007-01-01

381

Enzymatic hydrolysis of sago starch in a twin-screw extruder  

Microsoft Academic Search

Simultaneous gelatinisation and liquefaction of sago starch with a thermostable ?-amylase in a co-rotating twin-screw extruder was investigated. Maltodextrins with dextrose equivalent (DE) ranging from 0 to 10 were produced. Response surface methodology was used to study the influence of barrel temperature (70–130 °C), screw speed (70–160 rpm), enzyme concentration (0–1.0%) and feed moisture content (28.5–50.5%) on the extrudate properties.

S. Govindasamy; O. H. Campanella; C. G. Oates

1997-01-01

382

Horizontal ridge expansion and implant placement using screws: a report of two cases  

PubMed Central

Implants are typically placed after performing ridge expansion by inserting screws of gradually increasing thickness and good clinical outcomes are often obtained. We placed 11 implants in 6 patients, and one implant failed during osseointegration but it was replaced immediately after removal and successful prosthetic treatments were completed. During these surgeries, buccal cortical plate complete fractures do not occur. Inserting screws for ridge expansion is a successful and predictable technique for implant placement in narrow alveolar bone. PMID:25368836

Kim, Young-Kyun

2014-01-01

383

Electrical characterization of 4H-SiC avalanche photodiodes containing threading edge and screw dislocations  

NASA Astrophysics Data System (ADS)

The reverse voltage current characteristics and electroluminescence of small area 4H-SiC avalanche photodiodes were investigated and correlated with the presence of threading screw and edge dislocations. Localized electroluminescence was observed at threading dislocations at voltages close to breakdown whereas diodes without any extended defects exhibited uniform light emission in the active area. Diodes containing either edge or screw dislocations were found to have excess leakage currents and breakdown prematurely compared to diodes without dislocations.

Berechman, R. A.; Skowronski, M.; Soloviev, S.; Sandvik, P.

2010-06-01

384

Positioning of screw holes group based on digital camera and digital control drilling  

Microsoft Academic Search

Positioning of screw holes is an important production procedure for steel construction connecting with bolts. In this paper,\\u000a a new production method is presented, in which the digital camera is used for taking pictures of screw holes and other techniques\\u000a are advanced. This paper also indicates that the pixels of CCD chip in photogrammetry should be chosen as all geometric

Feng Wenhao; Li Jiansong; Yan Li; Su Guozhong; Yuan Xiuxiao; Zhong Shengzhang; Ji Huiming

2004-01-01

385

Arthroscopic Treatment of Slipped Capital Femoral Epiphysis Screw Impingement and Concomitant Hip Pathology  

PubMed Central

Impingement caused by screws used for stabilization of slipped capital femoral epiphysis can be treated arthroscopically. Although troublesome screws have traditionally been removed by open techniques, arthroscopic removal can successfully be achieved. In addition to affording the patient the benefits of minimally invasive surgery, surgeons also have the ability to arthroscopically address any concomitant hip pathology responsible for pain, including femoroacetabular impingement and labral tears. PMID:25264513

Howse, Elizabeth A.; Wooster, Benjamin M.; Mannava, Sandeep; Perry, Brad; Stubbs, Allston J.

2014-01-01

386

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

PubMed

We aimed to compare in vivo the stability of fixation of condylar fractures in sheep using sonic bone welding and standard titanium screws. We assessed stability of the osteosynthesis and maintenance of the height of the mandibular ramus. Height decreased slightly in both groups compared with the opposite side. The volume of the condyle increased considerably in both groups mainly because callus had formed. The results showed no significant disadvantages for pin fixation compared with osteosynthesis using titanium screws. PMID:22901526

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

2013-07-01

387

Biomimetic design of musculoskeletal humanoid knee joint with patella and screw-home mechanism  

Microsoft Academic Search

We are trying to create a novel musculoskeletal humanoid robot which has a humanlike structure. In this paper, we present a new knee joint which is usually simplified in robotics for high controllability. The knee joint has three human mimetic points, patella, screw-home mechanism and four-linked linkage. Patella is for a longer moment arm. Screw-home mechanism is for locking knee

Yuki Asano; Hironori Mizoguchi; Masahiko Osada; Toyotaka Kozuki; Junichi Urata; Tamon Izawa; Yuto Nakanishi; Kei Okada; Masayuki Inaba

2011-01-01

388

Morphology Evolution in PC\\/PE Blends with and without Compatibilization During Twin-Screw Extrusion  

Microsoft Academic Search

The morphology evolution in polycarbonate\\/polyethylene (PC\\/PE) blends with and without compatibilization in a twin-screw extruder was studied using a scanning electron microscope (SEM). The effects of screw speed and compatibilizer on the morphology of PC\\/PE blend during the extrusion were discussed in detail. It was found that the shape and size of the dispersed phase in the uncompatibilized PC\\/PE blend

Bo Yin; Jie Lan; Lan-Peng Li; Ming-Bo Yang

2010-01-01

389

Late-Onset Screw Migration into Iliac Vessels 21 years after Hip Arthrodesis  

PubMed Central

Iatrogenic injuries to the vascular system are a rare but serious complication of hip surgery. We report a case of an 83-year-old man who presented with intrapelvic migration of a screw into the space between the external iliac artery and vein 21 years after hip arthrodesis. The patient was treated with laparotomy, and the damaged artery was excised and sutured. This is the first case of a late vascular complication secondary to screw migration after hip arthrodesis. PMID:25336996

Hirai, Taishi; Inaba, Yutaka; Kobayashi, Naomi; Takakagawa, Shu; Yukizawa, Yohei; Ike, Hiroyuki; Saito, Tomoyuki

2014-01-01

390

Prognostic factors following surgical resection of distal bile duct cancer  

PubMed Central

Purpose Prognostic factors for distal bile duct cancer are contentious. This study was conducted to analyze the prognostic factors of distal bile duct cancer after surgery with the aim of identifying those associated with diminished survival. Methods Two hundred forty-one patients who underwent pylorus-preserving pancreaticoduodenectomy (PPPD) or Whipple procedure in our tertiary hospital from February 1995 to June 2011 were retrospectively analyzed. All patients were pathologically proven to have distal bile duct adenocarcinoma. Postoperative complications, survival, and well-known prognostic factors after resection for distal bile duct cancer were investigated. Results Preoperative elevated carbohydrate antigen 19-9 (CA 19-9) level (P = 0.006), positive resection margin (P < 0.001), advanced T stage (P = 0.043), and lymph node metastasis (P = 0.002) were significantly independent worse prognostic indicators by multivariate analysis of resectable distal bile duct cancer. Conclusion R0 resection is the most important so that frozen sections should be utilized aggressively during each operation. For the distal bile duct cancer with elevated preoperative CA 19-9 level or advanced stage, further study on postoperative adjuvant treatment may be warranted. PMID:24266011

Chung, Young Jae; Choi, Seong Ho; Heo, Jin Seok; Kim, Dong Hun

2013-01-01

391

Development of solid-lubricated ball-screws for use in space  

NASA Technical Reports Server (NTRS)

Ball-screws lubricated by solid lubricant films containing molybdenum disulphide are developed. The ball-screws (shaft diameter: phi 25 mm, length: 667 mm) were operated under a load of 40 to 120 N at a speed of 1.5 to 200 rpm at 10(exp -5) Pa. First, ball-screws made of stainless steel SUS 440C were studied using test equipment originally designed for this study. To reduce weight, the next step taken was to develop a ball-screw made of 6Al-4V-titanium. Long wear-life of more than 1 x 10(exp 7) revolutions was achieved with solid lubricated ball-screws made of SUS 440C and 6Al-4V-titanium in a hard vacuum. According to the surface profile of the shaft measured after 1 x 10(exp 7) revolutions, more solid lubricant remained on the surface of 6Al-4V-titanium than that of stainless steel. Auger and EPMA analysis confirmed lubrication was maintained by solid lubricant on nuts and screws after the lubricant films on the balls were worn off.

Chiba, Masatoshi; Gyougi, Toru; Nishimura, Makoto; Seki, Katsumi

1991-01-01

392

The empirical modeling of a Lysholm screw expander  

SciTech Connect

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 fluid at an inlet pressure of 0.827 MPa (120 psia). The inlet quality, engine speed and pressure ratio were independently varied to produce a three-dimensional data matrix of 104 data points. Statistical curve fitting methods were adapted to produce equations for mass flow rate and power output in terms of the three variables associated with the data matrix. These explicit equations were combined with a numerical steam table subroutine to produce an engine model. The predictive ability observed during the validation of the model is adequate for use in system modeling, such as a hybrid geothermal energy conversion system. Mass flow rates were predicted to within 3% of the measured values. For most conditions, predictions of power were within 3% of the measured values. The predictions for exhaust quality were within 1/2% of the measured values. Predictions of engine efficiency reflected the combined errors in prediction of power and mass flow rate. The maximum error in efficiency predictions was 1 part in 20.

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

1983-08-01

393

Empirical modeling of a Lysholm helical screw expander  

NASA Astrophysics Data System (ADS)

Testing of a Lysholm helical screw expander having a rotor diameter of 5.12 inches and an expansion ratio of 5.3 was performed with simulated geothermal fluid at an inlet pressure of 120 psia. The inlet quality, engine speed and pressure ratio were independently varied to produce a three-dimensional data matrix of 104 data points. Statistical curve fitting methods were adapted to produce equations for mass flow rate and power output in terms of the three variables associated with the data matrix. These explicit equations were combined with a steam table subroutine to produce a computer model for prediction of mass flow rate, power, efficiency and exhaust quality at a given set of operating conditions. The predictive ability observed during validation of the model is adequate for use in modeling of hybrid geothermal energy conversion systems. Mass flow rates were predicted to within 2.7% of the measured values. For most conditions, predictions of power were within 3.3% of the measured values. Predictions of efficiency reflected the combined errors in prediction of power and mass flow rate.

Brown, K. A.

1984-06-01

394

Stainless steel versus titanium volar multi-axial locking plates for fixation of distal radius fractures: a randomised clinical trial  

PubMed Central

Background Distal radius fractures are among the most common fractures seen in the hospital emergency department. Of these, over 40% are considered unstable and require some form of fixation. In recent years with the advent of low profile plating, open reduction and internal fixation (ORIF) using volar plates has become the surgical treatment of choice in many hospitals. However, it is currently unknown which plating system has the lowest complication rate and/or superior clinical and radiological outcomes following surgery. Few studies have compared different types of plates, which may have various features, different plate and screw designs or may be manufactured from different materials (for example, stainless steel or titanium). This study will specifically investigate and compare the clinical and radiological outcomes and complication rates of two commonly used volar plating systems for fixation of distal radius fractures: one made from stainless steel (Trimed™ Volar Plate, Trimed™, California, USA) and the other made from titanium (Medartis® Aptus Volar Plate, Medartis®, Basel, Switzerland). The primary aim of this study is to determine if there is a difference on the Patient Reported Wrist Evaluation six months following ORIF using a volar plate for adult patients with a distal radius fracture. Methods/Design This study will implement a randomized prospective clinical trial study design evaluating the outcomes of two different types of volar plates: one plate manufactured from stainless steel (Trimed™ Volar Plate) and one plate manufactured from titanium (Medartis® Aptus Volar Plate). The surgery will be performed at a major trauma hospital in Brisbane, Australia. Outcome measures including function, adverse events, range of movement, strength, disability, radiological findings and health-related quality of life will be collected at 6 weeks, 3, 6, 12 and 24 months following surgery. A parallel economic analysis will also be performed. This randomized clinical trial is due to deliver results in December 2016. Discussion Results from this trial will contribute to the evidence on operative management of distal radius fractures and plate material type. Trial registration ACTRN12612000969864 PMID:24612524

2014-01-01

395

Transforaminal lumbar interbody fusion using unilateral pedicle screw fixation plus contralateral translaminar facet screw fixation in lumbar degenerative diseases  

PubMed Central

Background: Transforaminal lumbar interbody fusion (TLIF) has been used in lumbar degenerative diseases. Some researchers have applied unilateral fixation in TLIF to reduce operational trauma without compromising the clinical outcome, but it is always suspected biomechanically unstable. The supplementary contralateral translaminar facet screw (cTLFS) seemed to be able to overcome the inherent drawbacks of unilateral pedicle screw (uPS) fixation theoretically. This study evaluates the safety, feasibility and efficacy of TLIF using uPS with cTLFS fixation in the treatment of lumbar degenerative diseases (LDD). Materials and Methods: 50 patients (29 male) underwent the aforementioned surgical technique for their LDD between December 2009 and April 2012. The results were evaluated based on visual analogue scale (VAS) of the leg and back, Japanese Orthopedic Association (JOA) score and Oswestry Disability Index (ODI) were recorded. The radiographic examinations in form of X-ray, computed tomography (CT) or magnetic resonance imaging was done preoperatively and 1 week, 3 months, 6 months, 12 months and 24 months postoperatively. The student t-test was used for comparison between the preoperative values and postoperative counterparts. P < 0.05 was considered to be statistically significant. Results: Among 50 patients, 22 received one level fusion and 28 two level's, with corresponding operation time and estimated blood loss being approximately 90 min, 150 ml and 120 min, 200 ml, respectively. No severe complications happened perioperatively. The mean VAS (back, leg) scores dropped from (7.6, 7.5) preoperatively to (2.1, 0.6) at 12 months’ followup, ODI from 49.1 preoperatively to 5.6 and JOA score raised from 10.6 preoperatively to 28.5, all P < 0.001, suggesting of good clinical outcome. From the three-dimensional reconstructed CT, 62 out of 70 segments displayed solid fusion with fusion rate of 88.6% at 12 months postoperatively. Conclusions: TLIF using uPS fixation plus cTLFS fixation is a safe, feasible and effective technique in the treatment of one or two level lumbar degenerative diseases short termly. PMID:25143640

Liu, Fubing; Jiang, Chun; Cao, Yuanwu; Jiang, Xiaoxing; Feng, Zhenzhou

2014-01-01

396

The distal residue-CO interaction in carbonmonoxy myoglobins: a molecular dynamics study of two distal histidine tautomers.  

PubMed Central

Four independent 90 ps molecular dynamics simulations of sperm-whale wild-type carbonmonoxy myoglobin (MbCO) have been calculated using a new AMBER force field for the haem prosthetic group. Two trajectories have the distal 64N delta nitrogen protonated, and two have the 64N epsilon nitrogen protonated; all water molecules within 16 A of the carbonyl O are included. In three trajectories, the distal residue remains part of the haem pocket, with the protonated distal nitrogen pointing into the active site. This is in contrast with the neutron diffraction crystal structure, but is consistent with the solution phase CO stretching frequencies (upsilon CO) of MbCO and various of its mutants. There are significant differences in the "closed" pocket structures found for each tautomer: the 64N epsilon H trajectories both show stable distal-CO interactions, whereas the 64N delta H tautomer) has a weaker interaction resulting in a more mobile distal side chain. One trajectory (a 64N delta H tautomer) has the distal histidine moving out into the "solvent", leaving the pocket in an "open" structure, with a large unhindered entrance to the active site. These trajectories suggest that the three upsilon CO frequencies observed for wild-type MbCO in solution, rather than representing significantly different Fe-C-O geometries as such, arise from three different haem pocket structures, each with different electric fields at the ligand. Each pocket structure corresponds to a different distal histidine conformer: the A3 band to the 64N epsilon H tautomer, the A1,2 band to the 64N delta H tautomer, and the A0 band to the absence of any significant interaction with the distal side chain. PMID:7696465

Jewsbury, P; Kitagawa, T

1994-01-01

397

Biplane double-supported screw fixation (F-technique): a method of screw fixation at osteoporotic fractures of the femoral neck.  

PubMed

The present work introduces a method of screw fixation of femoral neck fractures in the presence of osteoporosis, according to an original concept of the establishment of two supporting points for the implants and their biplane positioning in the femoral neck and head. The provision of two steady supporting points for the implants and the highly increased (obtuse) angle at which they are positioned allow the body weight to be transferred successfully from the head fragment onto the diaphysis, thanks to the strength of the screws, with the patient's bone quality being of least importance. The position of the screws allows them to slide under stress with a minimal risk of displacement. The method was developed in search of a solution for those patients for whom primary arthroplasty is contraindicated. The method has been analysed in relation to biomechanics and statics. For the first time, a new function is applied to a screw fixation-the implant is presented as a simple beam with an overhanging end. PMID:21966288

Filipov, Orlin

2011-10-01

398

Biomechanical study of the influence of stability for the pedicle screws fixation by injured vertebral screw when the pedicle cortex perforation.  

PubMed

Objective To explore the impact of pedicle cortex perforation on the stability of internal fixation of the vertebral body fracture,and to compare the stability of the vertebrae with pedicle cortex perforation after the injured vertebra transpedicular screw fixation by different ways. Methods A total of 36 fresh thoracic and lumbarvertebrae samples of adult sheep (T13-L1) were equally divided into four groups (A,B,C and D) by using the random number table method. The vertebral compression fracture was performed in the L1 vertebral body of the four groups using the Chiba's method. Four pedicle screws were fixed on the upper and lower injured vertebrae of four groups. In addition,the group C was fixed into a pedicle screw through the injured vertebrae;D group was set two pedicle screws through the injured vertebrae. Then the samples of group B,C,and D were removed a quarter of either side of lateral T14 thoracic pedicle,which was considered as the pedicle cortex perforation model. Four groups were performed fatigue test of 10 000 times by(300±105)N load. The drawing force of the screw and the stability of injured thoracolumbar vertebrae were measured and the differences in every group were compared. Results The axial compressive stiffness and maximum drawing force of screws in the other three groups were significantly higher than those in group B (all P=0.000). The maximum range of motion in four directions of group B were significantly larger than those of the other three groups (all P=0.000). The stiffness and the drawing force in groups C and D were significantly larger than those in the group A (all P=0.000),and the maximum range of motion in four directions of the two groups were lower than that of group A (P=0.002,P=0.005). Every testing indicator in group C had no significant difference when compared with group D (P>0.05). Conclusions The pedicle cortex perforation seriously affects the stability of the fractured vertebral body. The injured vertebra transpedicular screw can increase the stability of internal fixation. PMID:25176211

Shi, Yan; Feng, Su; Zhi-Min, Zhang

2014-08-31

399

Deviation analysis of atlantoaxial pedicle screws assisted by a drill template.  

PubMed

Although C1-C2 pedicle screw fixation provides an excellent fusion rate and rigid fixation, this technique has a potential risk. It is essential to develop an accurate screwing method to avoid this neurovascular injury. To develop and validate the accuracy of a novel navigational template for C1-C2 pedicle screw placement in cadaveric specimens, computed tomography scans with 1-mm-wide cuts were obtained of 32 cadaveric cervical specimens. The authors developed 64 three-dimensional full-scale templates that were created by computer modeling with a rapid prototyping technique from the computed tomography data. Drill templates were constructed with a custom trajectory for each level and side. The drill templates were used to guide the establishment of a pilot hole for screw placement. The average distances between ideal and actual entry points of the C1 pedicle screws in the x, y, and z axes were 0.16±0.46 mm, 0.11±0.52 mm, and -0.01±0.54 mm, respectively, on the left side and 0.11±0.49 mm, 0.01±0.56 mm, and -0.09±0.59 mm, respectively, on the right side. The average distances between ideal and actual entry points of the C2 pedicle screws in the x, y, and z axes were 0.05±0.54 mm, 0.20±0.59 mm, and -0.06±0.58 mm, respectively, on the left side and 0.17±0.55 mm, 0.1±0.58 mm, and -0.01±0.49 mm, respectively, on the right side. Factors related to human error and imprecision are responsible for most malpositioning of instrumentation. The rapid prototyping drill template for C1-C2 screw placement is described to minimize human error, although it introduces error related to computer software and variation in manufacturing. PMID:24810817

Hu, Yong; Yuan, Zhen-Shan; Kepler, Christopher K; Albert, Todd J; Xie, Hui; Yuan, Jian-Bing; Dong, Wei-Xin; Wang, Cheng-Tao

2014-05-01

400

A new free-hand pedicle screw placement technique with reference to the supraspinal ligament  

PubMed Central

We sought to compare the safety and accuracy of a new free-hand pedicle screw placement technique to that of the conventional technique. One hundred fifty-three consecutive adult patients with simple fracture in the thoracic or/and lumbar spine were alternately assigned to either the new free-hand or the conventional group. In the new free-hand technique group, preoperative computerized tomography (CT) images were used to calculate the targeted medial-lateral angle of each pedicle trajectory and the pedicle screw was inserted perpendicular to the correspond-ing supraspinal ligament. In the conventional technique group, the medial-lateral and cranial-caudal angle of each pedicle trajectory was determined by intraoperatively under fluoroscopic guidance. The accuracy rate of pedicle screw placement, the time of intraoperative fluoroscopy, the operating time and the amount of blood loss during operation were respectively compared. All screws were analyzed by using intraoperative radiographs, intraoperative triggered electromyography (EMG) monitoring data, postoperative CT data and clinical outcomes. The accuracy rate of pedicle screw placement in the new free-hand technique group and the conventional technique group was 96.3% and 94.2% (P < 0.05), respectively. The intraoperative fluoroscopy time of the new technique group was less than that of the conventional technique group (5.37 seconds vs. 8.79 seconds, P < 0.05). However, there was no statistical difference in the operating time and the amount of blood loss during operation (P > 0.05). Pedicle screw placement with the free-hand technique which keeps the screw perpendicular to the supraspinal ligament is an accurate, reliable and safe technique to treat simple fracture in the thoracic or lumbar spine. PMID:24474966

Li, Juming; Zhao, Hong; Xie, Hao; Yu, Lipeng; Wei, Jifu; Zong, Min; Chen, Feng; Zhu, Ziqiang; Zhang, Ning; Cao, Xiaojian

2014-01-01

401

Repair of Microdamage in Osteonal Cortical Bone Adjacent to Bone Screw  

PubMed Central

Up to date, little is known about the repair mode of microdamage in osteonal cortical bone resulting from bone screw implantation. In this study, self-tapping titanium cortical bone screws were inserted into the tibial diaphyses of 24 adult male rabbits. The animals were sacrificed at 1 day, 2 weeks, 1 month and 2 months after surgery. Histomorphometric measurement and confocal microscopy were performed on basic fuchsin stained bone sections to examine the morphological characteristics of microdamage, bone resorption activity and spatial relationship between microdamage and bone resorption. Diffuse and linear cracks were coexisted in peri-screw bone. Intracortical bone resorption was significantly increased 2 weeks after screw installation and reach to the maximum at 1 month. There was no significant difference in bone resorption between 1-month and 2-months groups. Microdamage was significantly decreased within 1 month after surgery. Bone resorption was predisposed to occur in the region of <100 µm from the bone-screw interface, where had extensive diffuse damage mixed with linear cracks. Different patterns of resorption cavities appeared in peri-screw bone. These data suggest that 1) the complex microdamage composed of diffuse damage and linear cracks is a strong stimulator for initiating targeted bone remodeling; 2) bone resorption activities taking place on the surfaces of differently oriented Haversian and Volkmann canals work in a team for the repair of extensive microdamage; 3) targeted bone remodeling is a short-term reaction to microdamage and thereby it may not be able to remove all microdamage resulting from bone screw insertion. PMID:24586702

Wang, Lei; Ye, Tingjun; Deng, Lianfu; Shao, Jin; Qi, Jin; Zhou, Qi; Wei, Li; Qiu, Shijing

2014-01-01

402

Magnesium transport in the renal distal convoluted tubule.  

PubMed

The distal tubule reabsorbs approximately 10% of the filtered Mg(2+), but this is 70-80% of that delivered from the loop of Henle. Because there is little Mg(2+) reabsorption beyond the distal tubule, this segment plays an important role in determining the final urinary excretion. The distal convoluted segment (DCT) is characterized by a negative luminal voltage and high intercellular resistance so that Mg(2+) reabsorption is transcellular and active. This review discusses recent evidence for selective and sensitive control of Mg(2+) transport in the DCT and emphasizes the importance of this control in normal and abnormal renal Mg(2+) conservation. Normally, Mg(2+) absorption is load dependent in the distal tubule, whether delivery is altered by increasing luminal Mg(2+) concentration or increasing the flow rate into the DCT. With the use of microfluorescent studies with an established mouse distal convoluted tubule (MDCT) cell line, it was shown that Mg(2+) uptake was concentration and voltage dependent. Peptide hormones such as parathyroid hormone, calcitonin, glucagon, and arginine vasopressin enhance Mg(2+) absorption in the distal tubule and stimulate Mg(2+) uptake into MDCT cells. Prostaglandin E(2) and isoproterenol increase Mg(2+) entry into MDCT cells. The current evidence indicates that cAMP-dependent protein kinase A, phospholipase C, and protein kinase C signaling pathways are involved in these responses. Steroid hormones have significant effects on distal Mg(2+) transport. Aldosterone does not alter basal Mg(2+) uptake but potentiates hormone-stimulated Mg(2+) entry in MDCT cells by increasing hormone-mediated cAMP formation. 1,25-Dihydroxyvitamin D(3), on the other hand, stimulates basal Mg(2+) uptake. Elevation of plasma Mg(2+) or Ca(2+) inhibits hormone-stimulated cAMP accumulation and Mg(2+) uptake in MDCT cells through activation of extracellular Ca(2+)/Mg(2+)-sensing mechanisms. Mg(2+) restriction selectively increases Mg(2+) uptake with no effect on Ca(2+) absorption. This intrinsic cellular adaptation provides the sensitive and selective control of distal Mg(2+) transport. The distally acting diuretics amiloride and chlorothiazide stimulate Mg(2+) uptake in MDCT cells acting through changes in membrane voltage. A number of familial and acquired disorders have been described that emphasize the diversity of cellular controls affecting renal Mg(2+) balance. Although it is clear that many influences affect Mg(2+) transport within the DCT, the transport processes have not been identified. PMID:11152754

Dai, L J; Ritchie, G; Kerstan, D; Kang, H S; Cole, D E; Quamme, G A

2001-01-01

403

The dynamic condylar screw in the management of subtrochanteric fractures: does judicious use of biological fixation enhance overall results?  

Microsoft Academic Search

Subtrochanteric fractures are fraught with certain anatomic, biologic and biomechanical challenges. Evolution of implants\\u000a like the Gamma nail, fixed-angle nail plates, compression hip screws and dynamic hip screws with trochanteric stabilization\\u000a plates underlines a persistent quest for a better implant. We studied the dynamic condylar screw DCS as an implant on a series\\u000a of 30 consecutive patients with subtrochanteric fractures.

Manzoor Ahmed Halwai; Shabir Ahmed Dhar; Mohammed Iqbal Wani; Mohammed Farooq Butt; Bashir Ahmed Mir; Murtaza Fazal Ali; Imtiyaz Hussain Dar

2007-01-01

404

Mechanical model and contouring analysis of high-speed ball-screw drive systems with compliance effect  

Microsoft Academic Search

The compliance effect of a high-speed ball-screw feed-drive system is modelled in this work. A mechanical model of a ball-screw feed drive system including the motor, ball-screw, coupling, supporting bearing, linear guide and machine structure was developed. It was found that at high acceleration, the mechanical compliance caused a significant contouring error. Smoothing the acceleration and deceleration control input command

J.-S. Chen; Y.-K. Huang; C.-C. Cheng

2004-01-01

405

Ejecta emplacement: from distal to proximal  

NASA Astrophysics Data System (ADS)

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

Artemieva, N.

2008-09-01

406

The evaluation and management of failed distal clavicle excision.  

PubMed

Excision of the distal clavicle (DCE) is a commonly carried out surgical procedure used in the management of acromioclavicular joint pathology. Although successful outcomes after both open and arthroscopic distal clavicle excision occur in a high percentage of patients, treatment failures have been reported, creating a difficult clinical scenario for the treating orthopedic surgeon. The most common mode of failure after DCE is persistent pain and potential etiologies include under-resection, over-resection leading to joint instability, postoperative stiffness, heterotopic ossification, untreated concomitant shoulder pathology, and postoperative infection. Less common causes of failure include distal clavicle fracture, reossification or fusion across the acromioclavicular joint, suprascapular neuropathy, and psychiatric illness. Persistent symptoms and disability after distal clavicle excision require a careful assessment of these potential causes of treatment failure and the formulation of a treatment plan, which may include conservative care, revision surgery, or coracoclavicular ligament reconstruction. Although careful patient selection, preoperative planning, proper surgical technique, and appropriate rehabilitation during the index procedure can minimize the likelihood of poor outcome, this paper reviews the work-up and management of cases of failed distal clavicle excision. PMID:20711054

Strauss, Eric J; Barker, Joseph U; McGill, Kevin; Verma, Nikhil N

2010-09-01

407

Biomechanical comparison of different combinations of hook and screw in one spine motion unit - an experiment in porcine model  

PubMed Central

Background The biomechanical performance of the hooks and screws in spinal posterior instrumentation is not well-characterized. Screw-bone interface failure at the uppermost and lowermost vertebrae is not uncommon. Some have advocated for the use of supplement hooks to prevent screw loosening. However, studies describing methods for combined hook and screw systems that fully address the benefits of these systems are lacking. Thus, the choice of which implant to use in a given case is often based solely on a surgeon’s experience instead of on the biomechanical features and advantages of each device. Methods We conducted a biomechanical comparison of devices instrumented with different combinations of hooks and screws. Thirty-six fresh low thoracic porcine spines were assigned to three groups (12 per group) according to the configuration used for of fixation: (1) pedicle screw; (2) lamina hook and (3) combination of pedicle screw and lamina hook. Axial pullout tests backward on transverse plane in the direction normal to the rods were performed using a material testing machine and a specially designed grip with self-aligned function. Results The pullout force for the pedicle screws group was significantly greater than for the hooks and the combination (p??0.05). Conclusions Pedicle screws achieve the maximal pullout strength for spinal posterior instrumentation. PMID:24913189

2014-01-01

408

Management of radionecrosis of the vulva and distal vagina  

SciTech Connect

Twelve patients were seen between January 1983 and June 1989 with the clinical diagnosis of radionecrosis of the vulva or distal vagina. Seven patients received radiation for vulvar cancer, three for distal vaginal cancer, and two for recurrent endometrial cancer. No patient healed spontaneously and the mean delay in surgical therapy was 8.5 months. The radionecrotic site was treated with local therapy, radical local excision (with or without colostomy), or exenteration. The operative defect was closed primarily in three patients and covered with local flaps or myocutaneous flaps in seven patients. The two patients with local care still have radionecrotic ulcers. One of three patients who were closed primarily continues to have an ulcer. All other patients have healed satisfactorily except one who died after two attempts to correct the problem. Radionecrosis of the vulva and distal vagina should generally be treated surgically.

Roberts, W.S.; Hoffman, M.S.; LaPolla, J.P.; Ruas, E.; Fiorica, J.V.; Cavanagh, D. (Univ. of South Florida, Tampa (USA))

1991-05-01

409

Management of fracture-dislocation of the lower cervical spine with the cervical pedicle screw system  

PubMed Central

INTRODUCTION Usually, cervical pedicle screw fixation has been considered too risky for neurovascular structures. The purpose of this study was to investigate the method and efficacy of the cervical pedicle screw system for fracture-dislocation of the cervical spine because of its rigid fixation. PATIENTS AND METHODS A prospective study was conducted involving 48 patients with cervical spine fracture-dislocation who underwent cervical pedicle screw fixation surgery between January 2003 and January 2007. All patients had various degrees of cord injury, and they were classified according to the American Spinal Cord Injury Association (ASIA) Impairment Scale: 18 cases were grade A, 15 grade B, 10 grade C, and 5 grade D. RESULTS Six months after the operation, all patients had achieved solid bony fusion and stable fixation of the related segments. Thirty patients with incomplete spinal cord injury improved their ASIA Impairment Scale classification by 1 to 2 grades after the operation. Eighteen patients with complete spinal cord injury had no improvement in neural function. However, nerve root symptoms such as pain and numbness were alleviated to some extent. CONCLUSIONS The cervical pedicle screw system is an effective and reliable method for the restoration of cervical stability. Sufficient pre-operative imaging studies of the pedicles and strict screw insertion technique should be emphasised. PMID:20487593

Zhou, Feng; Zou, Jun; Gan, Minfeng; Zhu, Ruofu; Yang, Huilin

2010-01-01

410

Biocompatibility testing of NiTi screws using immunohistochemistry on sections containing metallic implants.  

PubMed

NiTi is one of the most innovative concepts to have appeared in the field of metallic biomaterials in recent years but its biocompatibility remains controversial. We evaluated the biocompatibility of Nitinol screws using immunohistochemistry to observe the distribution of bone proteins during bone remodeling process around NiTi implant. Results were compared with screws made of Vitallium, c.p. titanium, Duplex austenitic-ferritic stainless steel (SAF), and Stainless Steel 316L. Screws were implanted in rabbit tibia for 3, 6, and 12 weeks. Embedding was performed in the hard resin Technovit, and for the immunohistochemical procedure undecalcified sections with bone-anchored implants could thus be used. The immunostaining method developed seemed to be a reliable technique to stain proteins in undecalcified sections. Biocompatibility results of the NiTi screws compared with the other screws showed a slower osteogenesis process characterized by no close contact between implant and bone, disorganized migration of osteoblasts around the implant, and a lower activity of osteonectin synthesis. PMID:8884502

Berger-Gorbet, M; Broxup, B; Rivard, C; Yahia, L H

1996-10-01

411

Efficacy analysis of pedicle screw internal fixation of fractured vertebrae in the treatment of thoracolumbar fractures  

PubMed Central

The present study aimed to discuss the method and effect of posterior internal fixation of thoracolumbar fractures strengthened by the vertical stress pedicle screw fixation of fractured vertebrae. Patients with single thoracolumbar fractures were examined retrospectively. Fourteen patients (group A) had been treated with vertical stress pedicle screw fixation of a fractured vertebra and sixteen patients (group B) received traditional double-plate fixation, as a control. All patients were diagnosed with fresh fractures with a complete unilateral or bilateral pedicle and no explosion of the inferior half of the vertebral body or inferior endplate. In group A, patients received conventional posterior distraction and lumbar lordosis restoration, as well as pedicle screws in the fractured vertebra in a vertical direction to relieve stress to achieve a local stress balance. All patients were followed up postoperatively for 4–18 months (average, 12.6 months). The vertical stress pedicle screw fixation assisted in the reduction of vertebrae fracture, which reduced the postoperative Cobb’s angle loss. There was a significant difference in the change of Cobb’s angle between the two groups one year after surgery (P<0.01). Conditional application of pedicle screws in a single thoracolumbar fracture enhances the stability of the internal fixation system and is conducive to the correction of kyphosis and maintenance of the corrective effects. PMID:23407593

HUANG, WEIJIE; LUO, TAO

2013-01-01

412

A video guided solution for screw insertion in orthopedic plate fixation  

NASA Astrophysics Data System (ADS)

In orthopedic and trauma surgery, metallic plates are used for reduction and fixation of bone fractures. In clinical practice, the intra-operative planning for screw fixation is usually based on fluoroscopic images. Screw fixation is then performed on a free-hand basis. As such, multiple attempts may be required in order to achieve an optimal positioning of the fixing screws. To help the physician insert the screws in accordance to the planned position, we propose a method for screw insertion guidance. Our approach uses a small video camera, rigidly placed on the drill, and a set of small markers that are rigidly fixed on a variable angle drill sleeve. In order to investigate the achievable accuracy of our setup, we simulate the estimation of the drill bit position under two different marker arrangements, planar and 3D, and different noise levels. Furthermore, we motivate our choices for marker design and position given the limited space available for marker positioning, the requirement for accurate position estimation of the drill bit and the illumination changes that could affect the surgical site. We also describe our proposed marker detection and tracking pipeline. Our simulation results let us conclude that we can achieve an accuracy of 1° and 1mm in the estimation of angular orientation and tip position of the drill bit respectively, provided that we have accurate marker detection.

Magaraggia, J.; Kleinszig, G.; Graumann, R.; Angelopoulou, E.; Hornegger, J.

2013-03-01

413

Plan to procedure: combining 3D templating with rapid prototyping to enhance pedicle screw placement  

NASA Astrophysics Data System (ADS)

Spinal fusion procedures involving the implantation of pedicle screws have steadily increased over the past decade because of demonstrated improvement in biomechanical stability of the spine. However, current methods of spinal fusion carries a risk of serious vascular, visceral, and neurological injury caused by inaccurate placement or inappropriately sized instrumentation, which may lead to patient paralysis or even fatality. 3D spine templating software developed by the Biomedical Imaging Resource (BIR) at Mayo Clinic allows the surgeon to virtually place pedicle screws using pre-operative 3D CT image data. With the template plan incorporated, a patient-specific 3D anatomic model is produced using a commercial rapid prototyping system. The pre-surgical plan and the patient-specific model then are used in the procedure room to provide real-time visualization and quantitative guidance for accurate placement of each pedicle screw, significantly reducing risk of injury. A pilot study was conducted at Mayo Clinic by the Department of Radiology, the Department of Orthopedics, and the BIR, involving seven complicated pediatric spine cases. In each case, pre-operative 3D templating was carried out and patient specific models were generated. The plans and the models were used intra-operatively, providing precise pedicle screw starting points and trajectories. Postoperative assessment by the surgeon confirmed all seven operations were successful. Results from the study suggest that patient-specific, 3D anatomic models successfully acquired from 3D templating tools are valuable for planning and conducting pedicle screw insertion procedures.

Augustine, Kurt E.; Stans, Anthony A.; Morris, Jonathan M.; Huddleston, Paul M.; Matsumoto, Jane M.; Holmes, David R., III; Robb, Richard A.

2010-02-01

414

Comparison of Superior Level Facet Joint Violations During Open and Percutaneous Pedicle Screw Placement  

PubMed Central

Background Superior-level facet joint violation by pedicle screws may result in increased stress to the level above the instrumentation and may contribute to adjacent segment disease (ASD). Previous studies have evaluated facet joint violations in open or percutaneous screw cases, but there are no reports describing a direct institutional comparison. Objective To compare the incidence of superior-level facet violation for open versus percutaneous pedicle screws, and evaluate patient and surgical factors that impact this outcome. Methods We reviewed 279 consecutive patients who underwent an index instrumented lumbar fusion from 2007 to 2011 for degenerative spine disease with stenosis with or without spondylolisthesis. We used a CT grading system which represents progressively increasing grades of facet joint violation. Patient and surgical factors were evaluated to determine their impact on facet violation. Results Our cohort consisted of 126 open and 153 percutaneous cases. Percutaneous procedures had a higher overall violation grade (p=0.018) and greater incidence of high-grade violations (p=0.0059) compared to open procedures. Bivariate analysis showed significantly greater violations in percutaneous cases for age<65, obesity, pedicle screws at L4, and 1- and 2-level surgeries. Multivariate analysis showed the percutaneous approach and depth of the spine to be independent risk factors for high-grade violations. Conclusion This study demonstrates greater facet violations for percutaneously placed pedicle screws compared to open. PMID:22843132

Babu, Ranjith; Park, Jong G.; Mehta, Ankit I.; Shan, Tony; Grossi, Peter M.; Brown, Christopher R.; Richardson, William J.; Isaacs, Robert E.; Bagley, Carlos A.; Kuchibhatla, Maragatha; Gottfried, Oren N.

2012-01-01

415

Continuous twin screw granulation: influence of process variables on granule and tablet quality.  

PubMed

The aim of the current study was to screen theophylline (125 mg) tablets manufactured via twin screw granulation in order to improve process understanding and knowledge of process variables that determine granule and tablet quality. A premix of theophylline anhydrate, ?-lactose monohydrate and PVP (ratio: 30/67.5/2.5,w/w) was granulated with demineralized water. Experiments were done using the high-shear wet granulation module (based on twin screw granulation) of the ConsiGma™-25 unit (a continuous tablet manufacturing system) for particle size enlargement. After drying, granules were compressed using a MODUL™ P tablet press (compression force: 10 kN, tablet diameter: 12 mm). Using a D-optimal experimental design, the effect of several process variables (throughput (10-25 kg/h), screw speed (600-950 rpm), screw configuration (number (2, 4, 6 and 12) and angle (30°, 60° and 90°) of kneading elements), barrel temperature (25-40°C) and method of binder addition (dry versus wet)) on the granulation process (torque and temperature increase in barrel wall), granule (particle size distribution, friability and flowability) and tablet (tensile strength, porosity, friability, disintegration time and dissolution) quality was evaluated. The results showed that the quality of granules and tablets can be optimized by adjusting specific process variables (number of kneading elements, barrel temperature and binder addition method) during a granulation process using a continuous twin screw granulator. PMID:22687571

Vercruysse, J; Córdoba Díaz, D; Peeters, E; Fonteyne, M; Delaet, U; Van Assche, I; De Beer, T; Remon, J P; Vervaet, C

2012-09-01

416

The Retroacetabular Angle Determines the Safe Angle for Screw Placement in Posterior Acetabular Fracture Fixation  

PubMed Central

Introduction. A method for the determination of safe angles for screws placed in the posterior acetabular wall based on preoperative computed tomography (CT) is described. It defines a retroacetabular angle and determines its variation in the population. Methods. The retroacetabular angle is the angle between the retroacetabular surface and the tangent to the posterior acetabular articular surface. Screws placed through the marginal posterior wall at an angle equal to the retroacetabular angle are extraarticular. Medial screws can be placed at larger angles whose difference from the retroacetabular angle is defined as the allowance angles. CT scans of all patients with acetabular fractures treated in our institute between September 2002 to July 2007 were used to measure the retroacetabular angle and tangent. Results. Two hundred thirty one patients were included. The average (range) age was 42 (15–74) years. The average (range) retroacetabular angle was 39 (30–47) degrees. The average (range) retroacetabular tangent was 36 (30–45)?mm. Conclusions. Placing the screws at an average (range) angle of 39 (33–47) degrees of anterior inclination with the retroacetabular surface makes them extraarticular. Angles for medial screws are larger. Safe angles can be calculated preoperatively with a computer program. PMID:24959359

Tadros, Ayman M. A.; Oxland, Thomas R.; O'Brien, Peter

2013-01-01

417

Designs and Techniques That Improve the Pullout Strength of Pedicle Screws in Osteoporotic Vertebrae: Current Status  

PubMed Central

Osteoporosis is a medical condition affecting men and women of different age groups and populations. The compromised bone quality caused by this disease represents an important challenge when a surgical procedure (e.g., spinal fusion) is needed after failure of conservative treatments. Different pedicle screw designs and instrumentation techniques have been explored to enhance spinal device fixation in bone of compromised quality. These include alterations of screw thread design, optimization of pilot hole size for non-self-tapping screws, modification of the implant's trajectory, and bone cement augmentation. While the true benefits and limitations of any procedure may not be realized until they are observed in a clinical setting, axial pullout tests, due in large part to their reproducibility and ease of execution, are commonly used to estimate the device's effectiveness by quantifying the change in force required to remove the screw from the body. The objective of this investigation is to provide an overview of the different pedicle screw designs and the associated surgical techniques either currently utilized or proposed to improve pullout strength in osteoporotic patients. Mechanical comparisons as well as potential advantages and disadvantages of each consideration are provided herein. PMID:24724097

Shea, Thomas M.; Laun, Jake; Gonzalez-Blohm, Sabrina A.; Doulgeris, James J.; Lee, William E.; Vrionis, Frank D.

2014-01-01

418

Designs and techniques that improve the pullout strength of pedicle screws in osteoporotic vertebrae: current status.  

PubMed

Osteoporosis is a medical condition affecting men and women of different age groups and populations. The compromised bone quality caused by this disease represents an important challenge when a surgical procedure (e.g., spinal fusion) is needed after failure of conservative treatments. Different pedicle screw designs and instrumentation techniques have been explored to enhance spinal device fixation in bone of compromised quality. These include alterations of screw thread design, optimization of pilot hole size for non-self-tapping screws, modification of the implant's trajectory, and bone cement augmentation. While the true benefits and limitations of any procedure may not be realized until they are observed in a clinical setting, axial pullout tests, due in large part to their reproducibility and ease of execution, are commonly used to estimate the device's effectiveness by quantifying the change in force required to remove the screw from the body. The objective of this investigation is to provide an overview of the different pedicle screw designs and the associated surgical techniques either currently utilized or proposed to improve pullout strength in osteoporotic patients. Mechanical comparisons as well as potential advantages and disadvantages of each consideration are provided herein. PMID:24724097

Shea, Thomas M; Laun, Jake; Gonzalez-Blohm, Sabrina A; Doulgeris, James J; Lee, William E; Aghayev, Kamran; Vrionis, Frank D

2014-01-01

419

The retroperitoneal, inguinal approach to distal part of the ureter  

PubMed Central

Introduction The inguinal approach to the distal part of the ureter allows the surgeon to perform various types of procedures and is considered to be one of the minimally invasive techniques in pediatric surgery. We aim to describe our initial experience with the surgery of the distal ureter performed through an inguinal mini–incision. Material and methods Between March 2012 and June 2013, 8 patients were treated using a minimally invasive inguinal technique. The indications for surgical correction were single system primary obstructive megaureter, obstructive megaureter of the upper pole in a duplex kidney and distal ureteral stones. In all patients with single system obstructive megaureter and significant hydronephrosis, ureterocutaneostomy was performed. In one patient with duplex system primary obstructive megaureter and significant hydronephrosis of the upper pole, ureteroureterostomy of the dilated ureter to the normal caliber ureter in the distal part was performed. In the second patient with duplex system primary obstructive megaureter and reduced marker excretion of the upper pole in renal scintigraphy, ureterocutaneostomy was performed. In both cases of distal ureteral stones, deposits were removed by a simple incision. Results We did not observe any perioperative or postoperative complications. The imaging studies have shown that ureteral dilatation decreased in all but one child in whom the upper pole and the ureter were resected due to lack of function. Conclusions The inguinal approach allows for the adequate visualization of the distal ureter, creating the conditions for implementation of the various procedures, reduces the risk of retrovesical plexus injury and minimizes visible scars. PMID:24982797

Urbanowicz, Wies?aw; Sulis?awski, Janusz; Dobrowolska–glazar, Barbara

2014-01-01

420

Mitochondrial dysfunction in distal axons contribute to HIV sensory neuropathy  

PubMed Central

Objective Accumulation of mitochondrial DNA (mtDNA) damage has been associated with aging and abnormal oxidative metabolism. We hypothesized that in human immunodeficiency virus associated sensory neuropathy (HIV-SN), damaged mtDNA accumulates in distal nerve segments and that a spatial pattern of mitochondrial dysfunction contribute to the distal degeneration of sensory nerve fibers. Methods We measured levels of common deletion mutations in mtDNA and expression levels of mitochondrial respiratory chain complexes of matched proximal and distal nerve specimens from patients with and without HIV-SN. In mitochondria isolated from peripheral nerves of simian immunodeficiency virus (SIV) infected macaques, a model of HIV-SN, we measured mitochondrial function and generation of reactive oxygen species. Results We identified increased levels of mtDNA common deletion mutation in post-mortem sural nerves of patients with HIV-SN as compared to uninfected patients or HIV patients without sensory neuropathy. Furthermore, we found that common deletion mutation in mtDNA was more prevalent in distal sural nerves compared to dorsal root ganglia. In a primate model of HIV-SN, freshly isolated mitochondria from sural nerves of macaques infected with a neurovirulent strain of SIV showed impaired mitochondrial function compared to mitochondria from proximal nerve segments. Interpretation Our findings suggest that mtDNA damage accumulates in distal mitochondria of long axons, especially in patients with HIV-SN, and that this may lead to reduced mitochondrial function in distal nerves relative to proximal segments. Although our findings are based on HIV-SN, if confirmed in other neuropathies, these observations could explain the length-dependent nature of most axonal peripheral neuropathies. PMID:21280080

Lehmann, Helmar C.; Chen, Weiran; Borzan, Jasenka; Mankowski, Joseph; Hoke, Ahmet

2010-01-01

421

Distal protection devices during percutaneous coronary and carotid interventions.  

PubMed

Distal embolization of particulate matter complicates percutaneous coronary and peripheral interventions more often than had been recognized until recently. A number of distal protection devices are under development. The PercuSurge GuardWiretrade mark is a balloon occlusion thrombectomy device approved by the United States Food and Drug Administration for saphenous vein graft intervention. A number of filter devices utilize an expandable filter mounted on the angioplasty guidewire to facilitate entrapment of particles and safe removal. The Parodi Anti-Emboli Systemtrade mark is an example of a catheter occlusion device that establishes protection by reversing blood flow in the target vessel. PMID:11806815

Fasseas, Panayotis; Orford, James L; Denktas, Ali E; Berger, Peter B

2001-01-01

422

Distal protection devices during percutaneous coronary and carotid interventions  

PubMed Central

Distal embolization of particulate matter complicates percutaneous coronary and peripheral interventions more often than had been recognized until recently. A number of distal protection devices are under development. The PercuSurge GuardWire™ is a balloon occlusion thrombectomy device approved by the United States Food and Drug Administration for saphenous vein graft intervention. A number of filter devices utilize an expandable filter mounted on the angioplasty guidewire to facilitate entrapment of particles and safe removal. The Parodi Anti-Emboli System™ is an example of a catheter occlusion device that establishes protection by reversing blood flow in the target vessel. PMID:11806815

Fasseas, Panayotis; Orford, James L; Denktas, Ali E; Berger, Peter B

2001-01-01

423

Nontraumatic osteonecrosis of the distal pole of the scaphoid  

PubMed Central

Post traumatic osteonecrosis of distal pole of scaphoid is very rare. We present a case of 34 years old male, drill operator by occupation with nontraumatic osteonecrosis of distal pole of the scaphoid. The patient was managed conservatively and was kept under regular follow-up every three months. The patient was also asked to change his profession. Two years later, the patient had no pain and had mild restriction of wrist movements (less than 15 degrees in either direction). The radiographs revealed normal density of the scaphoid suggesting revascularization. PMID:21430877

Garg, Bhavuk; Gupta, Himanshu; Kotwal, Prakash P

2011-01-01

424

In vitro comparison of resistance to implant failure in unstable trochanteric fractures fixed with intramedullary single screw versus double screw device  

PubMed Central

Background: The purpose of this study was to compare the resistance of intramedullary single screw device (Gamma nail) and double screw device proximal femoral nail (PFN) in unstable trochanteric fractures in terms of the number of cycles sustained, subsidence and implant failure in an axial loading test in cadaveric femora. Materials and Methods: The study was conducted on 18 dry cadaveric femoral specimens, 9 of these were implanted with a Gamma nail and 9 with PFN. There was no significant difference found in average dual energy X-ray absorptiometry value between both groups. The construct was made unstable (AO type 31A3.3) by removing a standard sized posteromedial wedge. These were tested on a cyclic physiological loading machine at 1 cycle/s with a load of 200 kg. The test was observed for 50,000 loading cycles or until implant failure, whichever occurred earlier. Peak displacements were measured and analysis was done to determine construct stiffness and gap micromotion in axial loading. Result: It was observed that there was statistically significant difference in terms of displacement at the fracture gap and overall construct stiffness of specimens of both groups. PFN construct group showed a mean subsidence of 1.02 mm and Gamma nail construct group showed mean subsidence of 2.36 mm after cycling. The average stiffness of Gamma nail group was 62.8 ± 8.4 N/mm which was significantly lower than average stiffness of the PFN group (80.4 ± 5.9 N/mm) (P = 0.03). In fatigue testing, 1 out of 9 PFN bone construct failed, while 5 of 9 Gamma nail bone construct failed. Conclusion: When considering micromotion (subsidence) and incidence of implant/screw failure, double screw device (PFN) had statistically significant lower micromotion across the fracture gap with axial compression and lower incidence of implant failure. Hence, double screw device (PFN) construct had higher stability compared to single screw device (GN) in an unstable trochanteric fracture femur model. PMID:24932039

Rastogi, Amit; Arun, GR; Singh, Vakil; Singh, Anant; Singh, Ashutosh K; Kumaraswamy, Vinay

2014-01-01

425

Measurement of the ground-state distributions in bistable mechanically interlocked molecules using slow scan rate cyclic voltammetry  

PubMed Central

In donor–acceptor mechanically interlocked molecules that exhibit bistability, the relative populations of the translational isomers—present, for example, in a bistable [2]rotaxane, as well as in a couple of bistable [2]catenanes of the donor–acceptor vintage—can be elucidated by slow scan rate cyclic voltammetry. The practice of transitioning from a fast scan rate regime to a slow one permits the measurement of an intermediate redox couple that is a function of the equilibrium that exists between the two translational isomers in the case of all three mechanically interlocked molecules investigated. These intermediate redox potentials can be used to calculate the ground-state distribution constants, K. Whereas, (i) in the case of the bistable [2]rotaxane, composed of a dumbbell component containing ?-electron-rich tetrathiafulvalene and dioxynaphthalene recognition sites for the ring component (namely, a tetracationic cyclophane, containing two ?-electron-deficient bipyridinium units), a value for K of 10 ± 2 is calculated, (ii) in the case of the two bistable [2]catenanes—one containing a crown ether with tetrathiafulvalene and dioxynaphthalene recognition sites for the tetracationic cyclophane, and the other, tetrathiafulvalene and butadiyne recognition sites—the values for K are orders (one and three, respectively) of magnitude greater. This observation, which has also been probed by theoretical calculations, supports the hypothesis that the extra stability of one translational isomer over the other is because of the influence of the enforced side-on donor–acceptor interactions brought about by both ?-electron-rich recognition sites being part of a macrocyclic polyether. PMID:22135467

Fahrenbach, Albert C.; Barnes, Jonathan C.; Li, Hao; Benitez, Diego; Basuray, Ashish N.; Fang, Lei; Sue, Chi-Hau; Barin, Gokhan; Dey, Sanjeev K.; Goddard, William A.; Stoddart, J. Fraser

2011-01-01

426

Visualization and understanding of the granulation liquid mixing and distribution during continuous twin screw granulation using NIR chemical imaging.  

PubMed

Over the last decade, there has been increased interest in the application of twin screw granulation as a continuous wet granulation technique for pharmaceutical drug formulations. However, the mixing of granulation liquid and powder material during the short residence time inside the screw chamber and the atypical particle size distribution (PSD) of granules produced by twin screw granulation is not yet fully understood. Therefore, this study aims at visualizing the granulation liquid mixing and distribution during continuous twin screw granulation using NIR chemical imaging. In first instance, the residence time of material inside the barrel was investigated as function of screw speed and moisture content followed by the visualization of the granulation liquid distribution as function of different formulation and process parameters (liquid feed rate, liquid addition method, screw configuration, moisture content and barrel filling degree). The link between moisture uniformity and granule size distributions was also studied. For residence time analysis, increased screw speed and lower moisture content resulted to a shorter mean residence time and narrower residence time distribution. Besides, the distribution of granulation liquid was more homogenous at higher moisture content and with more kneading zones on the granulator screws. After optimization of the screw configuration, a two-level full factorial experimental design was performed to evaluate the influence of moisture content, screw speed and powder feed rate on the mixing efficiency of the powder and liquid phase. From these results, it was concluded that only increasing the moisture content significantly improved the granulation liquid distribution. This study demonstrates that NIR chemical imaging is a fast and adequate measurement tool for allowing process visualization and hence for providing better process understanding of a continuous twin screw granulation system. PMID:24211658

Vercruysse, Jurgen; Toiviainen, Maunu; Fonteyne, Margot; Helkimo, Niko; Ketolainen, Jarkko; Juuti, Mikko; Delaet, Urbain; Van Assche, Ivo; Remon, Jean Paul; Vervaet, Chris; De Beer, Thomas

2014-04-01

427

Is minimally invasive application by intramedullary osteosynthesis in comparison with volar plating real benefit in the treatment of distal radius fractures?  

PubMed

Purpose of the study: Can minimally invasive intramedullary osteosynthesis of distal radius fractures provide better therapeutic results than multidirectional locking plates. Retrospective study of 68 patients operated for distal radius fractures, 18 were treated with intramedullary X-screw (XSCR) fixation and 50 with the multidirectional angle-stable plate system (APTUS). The evaluation at 1-year follow-up included functional status of the wrist and hand, and radiographic findings. In the XSCR group, the functional outcomes of the treated extremity did not achieve values comparable with those of the uninjured side in any of the parameters measured. The radiographic findings did not meet the requirements of successful healing due to failure to restore an anatomical volar tilt in 22.2% cases. In the APTUS group, comparable values of the injured and the uninjured side were achieved in radial deviation, ulnar deviation, pronation, supination and grip strength. The radiographic criteria of successful healing were met by all fractures treated by locking plate osteosynthesis. Implant migration associated with secondary displacement of bone fragments was recorded in 33.3 % of the XSCR patients and only in 4.0 % of the APTUS patients. The overall evaluation show that intramedullary osteosynthesis does not produce better treatment outcomes compared with plate osteosynthesis in indicated types of fractures. PMID:24856379

Vl?ek, Martin; Jaganjac, Edib; Pech, Jan; Jonáš, David; Kebrle, Radek

2014-05-01

428

An Alternative Explanation for a Screw-like Meteoric Train Photographed by Double-Station Observations  

NASA Astrophysics Data System (ADS)

Two-station observation of meteors, especially a meteor trains, provides an effective approach to the measurement of the physical parameters. We have collected four special groups of photographs of meteoric trains taken at two stations during Leonids 2001. One representative group has been measured and analyzed in detail. An analysis has been reported in our first paper. In this paper, an alternative explanation for the screw-like meteoric train is suggested based on some physical calculations. The results reveal that this train has a screw-like structure and, apparently, spoke beams. The mother meteor of this train may be negatively charged and moves forward along a left-hand screw trajectory under the effect of the geomagnetic field. The spoke beams might be the visual effect of the long time exposure of many particles released from the disintegrated meteoroid.

Wu, Guang-Jie

2007-12-01

429

Improved Screw Placement for Slipped Capital Femoral Epiphysis (SCFE) using Robotically-Assisted Drill Guidance  

PubMed Central

Slipped Capital Femoral Epiphysis (SCFE) is a common hip displacement condition in adolescents. In the standard treatment, the surgeon uses intra-operative fluoroscopic imaging to plan the screw placement and the drill trajectory. The accuracy, duration, and efficacy of this procedure are highly dependent on surgeon skill. Longer procedure times result in higher radiation dose, to both patient and surgeon. A robotic system to guide the drill trajectory might help to reduce screw placement errors and procedure time by reducing the number of passes and confirmatory fluoroscopic images needed to verify accurate positioning of the drill guide along a planned trajectory. Therefore, with the long-term goals of improving screw placement accuracy, reducing procedure time and intra-operative radiation dose, our group is developing an image-guided robotic surgical system to assist a surgeon with pre-operative path planning and intra-operative drill guide placement. PMID:25333154

Koutenaei, Bamshad Azizi; Guler, Ozgur; Wilson, Emmanuel; Thoranaghatte, Ramesh U.; Oetgen, Matthew; Navab, Nassir; Cleary, Kevin

2014-01-01

430

Bilateral Three-Level Lumbar Spondylolysis Repaired by Hook-Screw Technique  

PubMed Central

We report a case of bilateral three-level lumbar spondylolysis that was directly repaired by use of hook-screw technique. The patient complained of low back pain for 2 years that progressively worsened and was exacerbated with standing and walking. He also mentioned bilateral sciatalgia. The neurological examination was normal. Interestingly, we found bilateral lumbar spondylolysis in L3, L4, and L5 levels in imaging studies. After proving that spondylolysis was the source of the low back pain by local anesthetic agent injection, we used a direct technique for correction of spondylolysis by use of a hook-screw device plus decortications of lysis area and iliac crest autograft. We assessed the patient after surgery to evaluate pain recovery and fusion rate. The results were favorable and proved the efficacy of the hook-screw technique for treatment of symptomatic multilevel lumbar spondylolysis. PMID:24353947

Sharifi, Guive; Jahanbakhshi, Amin; Daneshpajouh, Behnam; Rahimizadeh, Abolfazl

2012-01-01

431

Autosomal dominant distal myopathy: Linkage to chromosome 14  

SciTech Connect

We have studied a family segregating a form of autosomal dominant distal myopathy (MIM 160500) and containing nine living affected individuals. The myopathy in this family is closest in clinical phenotype to that first described by Gowers in 1902. A search for linkage was conducted using microsatellite, VNTR, and RFLP markers. In total, 92 markers on all 22 autosomes were run. Positive linkage was obtained with 14 of 15 markers tested on chromosome 14, with little indication of linkage elsewhere in the genome. Maximum two-point LOD scores of 2.60 at recombination fraction .00 were obtained for the markers MYH7 and D14S64 - the family structure precludes a two-point LOD score {ge} 3. Recombinations with D14S72 and D14S49 indicate that this distal myopathy locus, MPD1, should lie between these markers. A multipoint analysis assuming 100% penetrance and using the markers D14S72, D14S50, MYH7, D14S64, D14S54, and D14S49 gave a LOD score of exactly 3 at MYH7. Analysis at a penetrance of 80% gave a LOD score of 2.8 at this marker. This probable localization of a gene for distal myopathy, MPD1, on chromosome 14 should allow other investigators studying distal myopathy families to test this region for linkage in other types of the disease, to confirm linkage or to demonstrate the likely genetic heterogeneity. 24 refs., 3 figs., 1 tab.

Laing, N.G.; Laing, B.A.; Wilton, S.D.; Dorosz, S.; Mastaglia, F.L.; Kakulas, B.A. [Australian Neuromuscular Research Institute, Perth (Australia); Robbins, P.; Meredith, C.; Honeyman, K.; Kozman, H.

1995-02-01

432

The effectiveness of distal soft tissue procedures in hallux valgus  

PubMed Central

Background Hallux valgus is a common disorder affecting mostly women population. Distal soft tissue procedure in the treatment of hallux valgus is one of the main operative techniques described. The aim of this study is to evaluate the outcomes of McBride’s distal soft tissue procedure in hallux valgus cases. Materials and methods This study includes 30 patients (27 women) having 31 hallux valgus, who were treated between 1999 and 2004. Modified McBride’s distal soft tissue procedure was carried out in all cases. Pain status of the cases was recorded by using VAS, clinical assessment described by Bonney and Macnab, and American Orthopaedic Foot and Ankle Society’s (AOFAS) score at the last follow up. Results The mean hallux valgus and intermetatarsal angles decreased from 31.4° and 13.8° to 13.5° and 10.5°, respectively, with an average follow-up period of 54.4 months. AOFAS’s score displayed significant improvement from 57 to 87. The mean VAS showed a significant decrease from 8.75 preoperatively to 2.1 at the last follow-up. According to Bonney and Macnab criteria, only one case was accepted as poor result due to 5° hallux varus. Conclusions McBride’s distal soft tissue procedure yields high rate of satisfaction for mild to moderate hallux valgus with no bony complications related to osteotomy. PMID:19384606

Ozturk, Hasan; Agus, Haluk; Altay, Taskin; Hancerli, Ozgur

2008-01-01

433

'Wristwatch fracture' of the distal radius: a new diagnosis?  

PubMed

Segmental forearm fractures are relatively uncommon in children, and their optimal management is unclear. We present an unusual segmental fracture of the distal radius in a 14 year old that appears to be related to a large metal wristwatch worn by the patient. It was successfully managed by dosed reduction and immobilisation in a plaster cast. PMID:19202823

Yewlett, A D; Khan, R; Clasper, J

2008-09-01

434

Supracondylar nailing of distal femoral fractures after total Knee Arthroplasty  

Microsoft Academic Search

We present results of supracondylar nailing in six patients who suffered distal femoral fractures above total knee arthroplasty. The average age of patients was 68 (42-92) years. All six fractures healed in a satisfactory alignment in an average duration of 14.6 weeks. There were no wound infection, loss of reduction or implant failure. All patients had regained their previous range

A. Kumar; A. Ali; M. S. Butt

435

Onlay urethroplasty with parameatal foreskin flap for distal hypospadias.  

PubMed

A new technique of onlay flap urethroplasty is described. The cosmetic and functional results of this logical extension of our one-stage urethroplasty with parameatal foreskin-flap have been good. The onlay urethroplasty with parameatal foreskin flap was recommended for the repair of distal hypospadias without chordee. PMID:1855528

Koyanagi, T; Nonomura, K; Asano, Y; Gotoh, T; Togashi, M

1991-01-01

436

Distal tibial fractures treated with hybrid external fixation  

Microsoft Academic Search

Management of distal tibia fractures remains challenging. The purpose of this study was to evaluate whether hybrid external fixation, as definite treatment, was associated with satisfactory results and low rate of complications. Between November 1999 and October 2006, 48 patients (33 men and 15 women) with a mean age of 45.6 years and a median ISS of 14.3 were admitted

G. C. Babis; P. Kontovazenitis; D. S. Evangelopoulos; P. Tsailas; K. Nikolopoulos; P. N. Soucacos

2010-01-01

437

Distal inflammatory myopathy: Unusual presentation of polymyositis or new entity?  

Microsoft Academic Search

New classification of idiopathic inflammatory myopathy (IIM) defined three major entities, polymyositis (PM), dermatomyositis (DM) and sporadic inclusion body myositis (s-IBM). We report the clinical, electrophysiological and pathological characteristics of three patients with a rare form of IIM not fulfilling the diagnostic criteria for any of these three major entities. The three patients presented with a subacute, distal asymmetrical weakness

Dalia Dimitri; Odile Dubourg; Thierry Maisonobe; Emmanuel Fournier; Brigitte Ranque; Pascal Laforêt; Jean-Marie Mussini; Christian Pagnoux; Anthony Béhin; Thomas Papo; Olivier Benveniste; Bruno Eymard; Serge Herson

2008-01-01

438

Prognostic factors after pancreatoduodenectomy for distal bile duct cancer.  

PubMed

Prognostic factors influencing long-term survival after radical resection for distal bile duct cancer have not been well established because of the rarity of this malignancy. The goal of this study was to identify main prognostic factors in patients undergoing pancreatoduodenectomy for distal bile duct carcinoma. A retrospective study consisting of 122 patients with distal bile duct cancer who underwent pancreatoduodenectomy in three major university hospitals was performed to identify the main prognostic factors. Major surgical complications occurred in 40 patients (32.8%), of whom eight died (6.6%) in the hospital. Overall actuarial survival (excluding hospital deaths) at 1-, 3-, and 5-year follow-up was 82.9, 49.4, and 32.7 per cent, respectively, with a median survival of 36 months. Univariate analysis showed that papillary tumor (P = 0.045), negative surgical margin (R0 resection, P = 0.005), earlier pT (P = 0.005), pTNM stage (P < 0.001), and absence of lymph node involvement (P < 0.0001) were significant predictors of survival. On multivariate analysis, only lymph node metastasis was shown to be an independent prognostic factor of survival (P = 0.036). Lymph node involvement was the most important survival predictor after a Whipple resection in patients with distal cholangiocarcinoma. PMID:22196654

Qiao, Qi-Lu; Zhang, Tai-Ping; Guo, Jun-Chao; Zhan, Han-Xiang; Zhao, Jian-Xun; Liu, Yu-Cun; Wan, Yuan-Lian; Leng, Xi-Sheng; Zhao, Yu-Pei

2011-11-01

439

[Clinical relevance of distal airway involvement in asthma].  

PubMed

Asthma continues to be a global health problem, despite advances in diagnostic techniques and treatment. The inflammatory nature of asthma is currently indisputable, as is the involvement of the entire respiratory tree, both the proximal and most distal airways, which has been demonstrated in multiple studies. The development of the therapeutic arsenal, with more potent drugs and improved inhalation devices, has allowed a certain control to be maintained over the inflammatory process, although the inability to reach the most distal points of the airways has posed a stumbling block that seems difficult to overcome. However, the available information on the real role of distal airway involvement in asthma remains very scarce. Physiopathological evidence shows that, in addition to the large airways, the small or distal airways (those with a diameter of less than 2 mm) substantially contribute to the severity of asthma. Several studies have shown that the inflammatory process seems to be more intense in this area. This finding has been related to nocturnal asthma and an increase in glucocorticoid receptor-beta-expressing cells, associated with corticosteroid-resistant asthma and fatal asthma. Equally, small airway involvement seems to be a highly important factor in asthma in the pediatric age group. PMID:21640280

Torrego Fernández, Alfons; Muñoz Cano, Rosa M

2011-04-01

440

Functional outcome of arthroscopic assisted fixation of distal radius fractures  

PubMed Central

Background: Many studies in literature have supported the role of wrist arthroscopy as an adjunct to the stable fixation of unstable intraarticular distal radial fractures. This article focuses on the surgical technique, indications, advantages, and results using wrist arthroscopy to assess articular reduction and evaluates the treatment of carpal ligament injuries and triangular fibrocartilage complex (TFCC) injuries in conjunction with the stable fixation of distal radial fractures. Materials and Methods: We retrospectively evaluated 27 patients (16 males and 11 females), who underwent stable fixation of intraarticular distal radial fractures with arthroscopic evaluation of the articular reduction and repair of associated carpal injuries. As per the AO classification, they were 9 C 1, 12 C2, 2 C3, 3 B 1, and 1 B2 fractures. The final results were evaluated by modified Mayo wrist scoring system. The average age was 41 years (range: 18-68 years). The average followup was of 26 months (range 24-52 months). Results: Five patients needed modification of the reduction and fixation after arthroscopic joint evaluation. Associated ligament lesions found during the wrist arthroscopy were TFCC tears (n=17), scapholunate ligament injury (n=8), and luno-triquetral ligament injury (n=1). Five patients had combined injuries i.e. included TFCC tear, scapholunate and/or lunotriquetral ligament tear. There were 20 excellent, 3 good, and 4 fair results using this score. Conclusion: The radiocarpal and mid carpal arthroscopy is a useful adjunct to stable fixation of distal radial fractures. PMID:23798761

Khanchandani, Prakash; Badia, Alejandro

2013-01-01

441

Haptic Distal Spatial Perception Mediated by Strings: Haptic "Looming"  

ERIC Educational Resources Information Center

Five experiments tested a haptic analog of optical looming, demonstrating string-mediated haptic distal spatial perception. Horizontally collinear hooks supported a weighted string held taut by a blindfolded participant's finger midway between the hooks. At the finger, the angle between string segments increased as the finger approached…

Cabe, Patrick A.

2011-01-01

442

A complete absorption mechanism of stacking fault tetrahedron by screw dislocation in copper  

NASA Astrophysics Data System (ADS)

It was frequently observed in experiments that stacking fault tetrahedron (SFT) can be completely absorbed by dislocation and generate defect-free channels in irradiated materials, but the mechanism is still open. In this paper, molecular dynamics (MD) was used to explore the dislocation mechanism of reaction between SFT and screw dislocation in copper. Our computational results reveal that, at high temperature, the SFT is completely absorbed by screw dislocation with the help of Lomer-Cottrell (LC) lock transforming into Lomer dislocation. This complete absorption mechanism is very helpful to understand the defect-free channels in irradiated materials.

Fan, Haidong; Wang, Qingyuan

2013-10-01

443