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https://www.readbyqxmd.com/read/28109557/does-cutting-a-plaster-window-weaken-its-strength
#1
Nimesh Patel, Lance Wilson, Guy Wansbrough
INTRODUCTION: A plaster window is usually created over a pressure area, or in some cases a wound or suture line. This can relieve pressure at the site, and provide an opportunity to change dressings, check on drainage, and inspect a wound or ulcer. There is concern that this can have an effect on its function to provide fracture stability, and weakens the plaster. The biomechanical effects of windowing on plaster strength were therefore investigated, as it has not previously been reported...
January 16, 2017: Injury
https://www.readbyqxmd.com/read/28104322/effect-from-rotational-speed-on-torsional-resistance-of-the-nickel-titanium-instruments
#2
Jung-Hong Ha, Sang Won Kwak, Sung Kyo Kim, Asgeir Sigurdsson, Hyeon-Cheol Kim
INTRODUCTION: The purpose of this study was to evaluate differences in torsional resistance using up-regulated speed of rotational spindle. METHODS: Three NiTi rotary instrument systems were selected in this study: K3XF (SybronEndo, Glendora, CA), BLX (B&L Biotech, Ansan, Korea), and OneShape (MicroMega, Besançon, France). The tip size and taper for all files were #25 and 0.06. Experimental groups (n = 10/group) were assigned to 2-, 60-, 350-, and 600-rpm groups by the rotational speed of spindle...
January 16, 2017: Journal of Endodontics
https://www.readbyqxmd.com/read/28104320/torsional-performance-of-protaper-gold-rotary-instruments-during-shaping-of-small-root-canals-after-2-different-glide-path-preparations
#3
Ana Arias, Rafaela Andrade de Vasconcelos, Alexis Hernández, Ove A Peters
INTRODUCTION: The purpose of this study was to assess the ex vivo torsional performance of a novel rotary system in small root canals after 2 different glide path preparations. METHODS: Each independent canal of 8 mesial roots of mandibular molars was randomly assigned to achieve a reproducible glide path with a new set of either PathFile #1 (Dentsply Maillefer, Ballaigues, Switzerland) and #2 or ProGlider (Dentsply Maillefer) after negotiation with a 10 K-file...
January 16, 2017: Journal of Endodontics
https://www.readbyqxmd.com/read/28103852/stiffness-of-the-locking-compression-plate-as-an-external-fixator-for-treating-distal-tibial-fractures-a-biomechanics-study
#4
Wei Liu, Lihui Yang, Xiaochuan Kong, Likun An, Gang Hong, Zicheng Guo, Lei Zang
BACKGROUND: Locking compress plate, as external fixator, is an attractive technique for distal tibial fracture treatment. But it still remains unclear whether the external LCP has sufficient stiffness. Thus, the present study aims to make a comprehensive evaluation of the stiffness of external locking compress plate when it is used as an external fixator in distal tibial fractures treatment. METHODS: Composite tibia was used to simulate distal tibia fracture (Orthopedic Trauma Association type 43 A3 fracture)...
January 19, 2017: BMC Musculoskeletal Disorders
https://www.readbyqxmd.com/read/28102461/rnahelix-computational-modeling-of-nucleic-acid-structures-with-watson-crick-and-non-canonical-base-pairs
#5
Dhananjay Bhattacharyya, Sukanya Halder, Sankar Basu, Debasish Mukherjee, Prasun Kumar, Manju Bansal
Comprehensive analyses of structural features of non-canonical base pairs within a nucleic acid double helix are limited by the availability of a small number of three dimensional structures. Therefore, a procedure for model building of double helices containing any given nucleotide sequence and base pairing information, either canonical or non-canonical, is seriously needed. Here we describe a program RNAHelix, which is an updated version of our widely used software, NUCGEN. The program can regenerate duplexes using the dinucleotide step and base pair orientation parameters for a given double helical DNA or RNA sequence with defined Watson-Crick or non-Watson-Crick base pairs...
January 19, 2017: Journal of Computer-aided Molecular Design
https://www.readbyqxmd.com/read/28097243/range-of-motion-sacral-screw-and-rod-strain-in-long-posterior-spinal-constructs-a-biomechanical-comparison-between-s2-alar-iliac-screws-with-traditional-fixation-strategies
#6
Chester E Sutterlin, Antony Field, Lisa A Ferrara, Andrew L Freeman, Kevin Phan
BACKGROUND: S1 screw failure and L5/S1 non-union are issues with long fusions to S1. Improved construct stiffness and S1 screw offloading can help avoid this. S2AI screws have shown to provide similar stiffness to iliac screws when added to L3-S1 constructs. We sought to examine and compare the biomechanical effects on an L2-S1 pedicle screw construct of adding S2AI screws, AxiaLIF, L5-S1 interbody support via transforaminal lumbar interbody fusion (TLIF), and to examine the effect of the addition of cross connectors to each of these constructs...
December 2016: Journal of Spine Surgery (Hong Kong)
https://www.readbyqxmd.com/read/28095698/evaluation-of-the-coupled-two-dimensional-main-chain-torsional-potential-in-modeling-intrinsically-disordered-proteins
#7
Ya Gao, Chaomin Zhang, John Z H Zhang, Ye Mei
Intrinsically Disordered Proteins (IDPs) carry out crucial biological functions in essential biological processes of life. Due to the highly dynamic and conformationally heterogeneous nature of the disordered states of IDPs, molecular dynamics simulations are becoming an indispensable tool for the investigation of the conformational ensembles and dynamic properties of IDPs. Nevertheless, there is still no consensus on the most reliable force field in molecular dynamics simulations for IDPs hitherto. In this work, a recently proposed AMBER99SB2D force field is evaluated in modeling some disordered polypeptides and proteins by checking its ability in reproducing NMR experimental data...
January 18, 2017: Journal of Chemical Information and Modeling
https://www.readbyqxmd.com/read/28095358/axial-and-torsional-stiffness-of-pediatric-prosthetic-feet
#8
Paolo Taboga, Alena M Grabowski
BACKGROUND: Prosthetic stiffness likely affects the walking biomechanics of toddlers and children with leg amputations, but the actual stiffness values for prostheses are not reported by manufacturers or in standardized testing procedures. AIM: We measured axial (kA) and torsional (kT) stiffness from four brands of pediatric prosthetic feet (Trulife, Kingsley Mfg. Co., TRS Incorporated, and College Park Industries) over a range of foot sizes. METHODS: We applied forces and torques onto prostheses with a materials testing machine that replicated those exhibited in vivo by using the kinetics measured from four non-amputee toddlers (2-3years) during walking...
January 5, 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/28094424/ex-vivo-torsional-properties-of-a-2-5-mm-veterinary-interlocking-nail-system-in-canine-femurs-comparison-with-a-2-4-mm-limited-contact-bone-plate
#9
Aline S Macedo, Noel M M Moens, John Runciman, Tom W G Gibson, Bruno W Minto
OBJECTIVE: To evaluate the torsional properties of the Targon(®) Vet Nail System (TVS) in small canine femurs and to compare these properties to those of the 2.4 mm LC-DCP(®) plates. METHODS: Thirty-six cadaveric femurs were allocated to three groups (n = 12). In all bones, points just distal to the lesser trochanter and just proximal to the fabellae were marked and a midshaft transverse osteotomy was performed. Group 1: bones were fixed with the 2.5 mm TVS with the bolts applied at the pre-identified marks...
January 17, 2017: Veterinary and Comparative Orthopaedics and Traumatology: V.C.O.T
https://www.readbyqxmd.com/read/28094253/dynamical-importance-of-van-der-waals-saddle-and-excited-potential-surface-in-c-1-d-d2-complex-forming-reaction
#10
Zhitao Shen, Haitao Ma, Chunfang Zhang, Mingkai Fu, Yanan Wu, Wensheng Bian, Jianwei Cao
Encouraged by recent advances in revealing significant effects of van der Waals wells on reaction dynamics, many people assume that van der Waals wells are inevitable in chemical reactions. Here we find that the weak long-range forces cause van der Waals saddles in the prototypical C((1)D)+D2 complex-forming reaction that have very different dynamical effects from van der Waals wells at low collision energies. Accurate quantum dynamics calculations on our highly accurate ab initio potential energy surfaces with van der Waals saddles yield cross-sections in close agreement with crossed-beam experiments, whereas the same calculations on an earlier surface with van der Waals wells produce much smaller cross-sections at low energies...
January 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28093411/age-and-sex-related-influences-on-left-ventricular-mechanics-in-elderly-individuals-free-of-prevalent-heart-failure-the-aric-study-atherosclerosis-risk-in-communities
#11
Chung-Lieh Hung, Alexandra Gonçalves, Amil M Shah, Susan Cheng, Dalane Kitzman, Scott D Solomon
BACKGROUND: Advanced age is related to left ventricular (LV) remodeling. We sought to investigate the relationships between aging, elevated hemodynamic load, cardiac mechanics, and LV remodeling in an elderly community-based population. METHODS AND RESULTS: We studied 1105 subjects (76±5 years, 61% women) without prevalent heart failure, who attended the visit 5 of the ARIC study (Atherosclerosis Risk in Communities). LV global longitudinal strain, global circumferential strain, and torsion indices were analyzed using 3-dimensional echocardiography...
January 2017: Circulation. Cardiovascular Imaging
https://www.readbyqxmd.com/read/28088311/prevalence-of-preoperative-penile-abnormalities-among-voluntary-male-medical-circumcision-patients-in-swaziland
#12
Anthony R Oddo, Elizabeth Ruedrich, Christopher Zust, Lindsey Marugg, Echo VanderWal, Harry VanderWal, Rebekah Sartori, Ronald Markert, Mary C McCarthy
BACKGROUND: Circumcision has been found to be an effective strategy for lowering the transmission of HIV in Africa. The Luke Commission, a mobile hospital outreach program, has used this information to decrease the rate of HIV in Swaziland by performing voluntary male medical circumcisions throughout the country. During many of these circumcisions, genital medical conditions and penile abnormalities are simultaneously discovered and corrected. PURPOSE: The goal of our study was to evaluate the prevalence of penile abnormalities discovered and treated during voluntary male medical circumcisions performed by The Luke Commission (TLC) throughout rural Swaziland...
January 3, 2017: Journal of Pediatric Surgery
https://www.readbyqxmd.com/read/28081051/procedure-oriented-torsional-anatomy-of-the-forearm-for-spasticity-injection-erratum
#13
(no author information available yet)
No abstract text is available yet for this article.
January 2017: Journal of Computer Assisted Tomography
https://www.readbyqxmd.com/read/28079730/biomechanical-comparison-of-cadaveric-and-commercially-available-synthetic-osteoporotic-bone-analogues-in-a-locked-plate-fracture-model-under-torsional-loading
#14
Edward H Becker, Hyunchul Kim, Michael Shorofsky, Adam H Hsieh, Jeffrey D Watson, Robert V O'Toole
OBJECTIVES: Biomechanical studies of osteoporotic bone have used synthetic models rather than cadaveric samples because of decreased variability, increased availability, and overall ease of use of synthetic models. We compared the torsional mechanical properties of cadaveric osteoporotic bone with those of currently available synthetic osteoporotic bone analogues. METHODS: We tested 12 osteoporotic cadaveric humeri and 6 specimens each of 6 types of synthetic analogues...
January 5, 2017: Journal of Orthopaedic Trauma
https://www.readbyqxmd.com/read/28076813/signatures-of-mechanosensitive-gating
#15
REVIEW
Richard G Morris
The question of how mechanically gated membrane channels open and close is notoriously difficult to address, especially if the protein structure is not available. This perspective highlights the relevance of micropipette-aspirated single-particle tracking-used to obtain a channel's diffusion coefficient, D, as a function of applied membrane tension, σ-as an indirect assay for determining functional behavior in mechanosensitive channels. While ensuring that the protein remains integral to the membrane, such methods can be used to identify not only the gating mechanism of a protein, but also associated physical moduli, such as torsional and dilational rigidity, which correspond to the protein's effective shape change...
January 10, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28072652/in-vivo-correlation-of-radiographic-scoring-rust-and-biomechanical-data-in-a-sheep-osteotomy-model-can-we-define-union-radiographically
#16
Paul Tornetta, Jody Litrenta, William Ricci, Roy Sanders, Robert V O'Toole, Jason W Nascone, Henry Faber, Darren Wilson
OBJECTIVE: To determine 1) the reliability of the standard and modified RUST score in a sheep osteotomy model, and 2) the standard and modified RUST score that represents biomechanical union. DESIGN: The tibia cortices in a sheep osteotomy model treated by intramedullary nails were radiographically evaluated using standard and modified RUST scores. Scores that correlated with biomechanical union, based on the torsional stiffness of the contralateral tibia, were determined...
December 22, 2016: Journal of Orthopaedic Trauma
https://www.readbyqxmd.com/read/28071914/synthesis-and-nmr-analysis-of-a-conformationally-controlled-%C3%AE-turn-mimetic-torsion-balance
#17
Alyssa B Lypson, Craig S Wilcox
The molecular torsion balance concept was applied to a new conformationally controlled scaffold and synthesized to accurately evaluate pairwise amino acid interactions in an antiparallel β-sheet motif. The scaffold's core design combines (ortho-tolyl)amide and o,o,o'-trisubstituted biphenyl structural units to provide a geometry better-suited for intramolecular hydrogen bonding. Like the dibenzodiazocine hinge of the traditional torsion balance, the (ortho-tolyl)amide unit offers restricted rotation around an N-aryl bond...
January 10, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28067466/anterior-lumbar-interbody-fusion-integrated-screw-cages-intrinsic-load-generation-subsidence-and-torsional-stability
#18
Yusuf Assem, Matthew H Pelletier, Ralph J Mobbs, Kevin Phan, William R Walsh
OBJECTIVE: To perform a repeatable idealized in vitro model to evaluate the effects of key design features and integrated screw fixation on unloaded surface engagement, subsidence, and torsional stability. METHODS: We evaluated four different stand-alone anterior lumbar interbody fusion (ALIF) cages with two, three, and four screw designs. Polyurethane (saw-bone) foam blocks were used to simulate the vertebral bone. Fuji Film was used to measure the contact footprint, average pressure, and load generated by fixating the cages with screws...
January 9, 2017: Orthopaedic Surgery
https://www.readbyqxmd.com/read/28066739/hip-instability-a-review-of-hip-dysplasia-and-other-contributing-factors
#19
REVIEW
Matthew J Kraeutler, Tigran Garabekyan, Cecilia Pascual-Garrido, Omer Mei-Dan
BACKGROUND: Hip instability has classically been associated with developmental dysplasia of the hip (DDH) in newborns and children. However, numerous factors may contribute to hip instability in children, adolescents, and adults. PURPOSE: This review aims to concisely present the literature on hip instability in patients of all ages in order to guide health care professionals in the appropriate diagnosis and treatment of the various disorders which may contribute to an unstable hip...
July 2016: Muscles, Ligaments and Tendons Journal
https://www.readbyqxmd.com/read/28064078/novel-indolizino-8-7-b-indole-hybrids-as-anti-small-cell-lung-cancer-agents-regioselective-modulation-of-topoisomerase-ii-inhibitory-and-dna-crosslinking-activities
#20
Sue-Ming Chang, Wilson Christian, Ming-Hsi Wu, Tai-Lin Chen, Yi-Wen Lin, Ching-Shu Suen, Hima Bindu Pidugu, Dilip Detroja, Anamik Shah, Ming-Jing Hwang, Tsann-Long Su, Te-Chang Lee
A novel series of bis(hydroxymethyl)indolizino[8,7-b]indole hybrids composed of β-carboline (topoisomerase I/II inhibition) and bis(hydroxymethyl)pyrrole (DNA cross-linking) are synthesized for antitumor evaluation. Of tumor cell lines tested, small cell lung cancer (SCLC) cell lines are the most sensitive to the newly synthesized compounds. These hybrids induce cell cycle arrest at the G2/M phase, trigger tumor cell apoptotic death, and display diverse mechanisms of action involving topoisomerase II (Topo II) inhibition and induction of DNA cross-linking...
December 24, 2016: European Journal of Medicinal Chemistry
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