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Neutral zone

Ruozhou Zhou, Zhiping Huang, Xiang Liu, Jie Tong, Wei Ji, Sheting Liu, Qingan Zhu
BACKGROUND: Polyetheretherketone rod constructs provide adequate spinal stability. Kinematics and load sharing of anterior thoracolumbar reconstruction with polyetheretherketone rods under preload remains unknown. METHODS: Eight human cadaveric specimens (T11-L3) were subjected to a pure moment of 5.0Nm in flexion-extension, lateral bending and axial rotation, and flexion-extension with a compressive preload of 300N. An anterior reconstruction of L1 corpectomy was conducted with a surrogate bone graft and anterior rod constructs (polyetheretherketone or titanium rods)...
October 5, 2016: Clinical Biomechanics
Behdad Pouran, Vahid Arbabi, Amir A Zadpoor, Harrie Weinans
The metabolic function of cartilage primarily depends on transport of solutes through diffusion mechanism. In the current study, we use contrast enhanced micro-computed tomography to determine equilibrium concentration of solutes through different cartilage zones and solute flux in the cartilage, using osteochondral plugs from equine femoral condyles. Diffusion experiments were performed with two solutes of different charge and approximately equal molecular weight, namely iodixanol (neutral) and ioxaglate (charge=-1) in order to isolate the effects of solute's charge on diffusion...
October 6, 2016: Medical Engineering & Physics
Anna Takácsi-Nagy, Ferenc Kilár, Wolfgang Thormann
This paper comprises a continuation of computer simulation studies dealing with carrier ampholyte based CIEF in presence of narrow pH gradients. With this technique, amphoteric sample components with pI values outside the pH gradient are migrating isotachophoretically toward the cathode or anode whereas components with pI values within the gradient become focused. In order to understand the processes occurring in presence of the electric field, the behavior of both carrier ampholytes and amphoteric sample components is investigated by computer modeling...
October 4, 2016: Electrophoresis
Luana G M Ferrara, Gregor D Wallat, Lucile Moynié, Naresh N Dhanasekar, Soumeya Aliouane, Silvia Acosta-Gutiérrez, Jean-Marie Pagès, Jean-Michel Bolla, Mathias Winterhalter, Matteo Ceccarelli, James H Naismith
The Gram-negative organism Campylobacter jejuni is the major cause of food poisoning. Unlike Escherichia coli, which has two major porins, OmpC and OmpF, C. jejuni has one, termed major outer membrane protein (MOMP) through which nutrients and antibiotics transit. We report the 2.1-Å crystal structure of C. jejuni MOMP expressed in E. coli and a lower resolution but otherwise identical structure purified directly from C. jejuni. The 2.1-Å resolution structure of recombinant MOMP showed that although the protein has timeric arrangement similar to OmpC, it is an 18-stranded, not 16-stranded, β-barrel...
September 30, 2016: Journal of Molecular Biology
Eelin Tan, Tian Wang, Matthew H Pelletier, William R Walsh
BACKGROUND: Studies on the effects of cement augmentation or vertebroplasty on multi-level spine after vertebral compression fractures are lacking. This paper seeks to establish a 3-vertebrae ovine model to determine the impact of compression fracture on spine biomechanics, and to discover if cement augmentation can restore mechanical stability to fractured spine. METHODS: Five lumbar spine segments (L1-L3) were obtained from 5-year-old female Merino sheep. Standardized wedge-compression fractures were generated in each L2 vertebra, and then augmented with polymethyl methacrylate (PMMA) cement mixed with 30% barium sulphate powder...
June 2016: J Spine Surg
Behdad Pouran, Vahid Arbabi, Harrie Weinans, Amir A Zadpoor
Transport of solutes helps to regulate normal physiology and proper function of cartilage in diarthrodial joints. Multiple studies have shown the effects of characteristic parameters such as concentration of proteoglycans and collagens and the orientation of collagen fibrils on the diffusion process. However, not much quantitative information and accurate models are available to help understand how the characteristics of the fluid surrounding articular cartilage influence the diffusion process. In this study, we used a combination of micro-computed tomography experiments and biphasic-solute finite element models to study the effects of three parameters of the overlying bath on the diffusion of neutral solutes across cartilage zones...
September 17, 2016: Computers in Biology and Medicine
Mariana Feijó de Oliveira, Edson Rodrigues Júnior, Cecilia Nahomi Kawagoe Suda, Gannabathula Sree Vani, Lucélia Donatti, Edson Rodrigues, Helena Passeri Lavrado
The gastropod Nacella concinna is the most conspicuous macroinvertebrate of the intertidal zone of the Antarctic Peninsula and adjacent islands. Naturally high levels of copper and cadmium in coastal marine ecosystems are accumulated in N. concinna tissues. We aimed to study the effects of metal cations on N. concinna arginase in the context of possible adaptive microevolution. Gills and muscle had the highest argininolytic activity, which was concentrated in the cytosol in both tissues. Gills had the highest levels of arginase and may be involved in the systemic control of l-arginine levels...
September 22, 2016: Ecotoxicology and Environmental Safety
Zhen Liu, Zhongyuan Huang, Feifei Cheng, Zhanhu Guo, Guangdi Wang, Xu Chen, Zhe Wang
Durable, highly efficient, and economic sound electrocatalysts for CO electrooxidation (COE) are the emerging key for wide variety of energy solutions, especially fuel cells and rechargeable metal-air batteries. Herein, we report the novel system of nickel-aluminum double layered hydroxide (NiAl-LDH) nanoplates on carbon nanotubes (CNTs) network. The formulation of such complexes system was to be induced through the assistance of gold nanoparticles in order to form dual-metal active sites so as to create a extended Au/NiO two phase zone...
2016: Scientific Reports
Zbigniew Borowski, Magdalena Świsłocka, Maciej Matosiuk, Paweł Mirski, Kamil Krysiuk, Magdalena Czajkowska, Anetta Borkowska, Mirosław Ratkiewicz
The trajectories of postglacial range expansions, the occurrence of lineage patches and the formation and maintenance of secondary contact between lineages may mostly reflect neutral demographic processes, including density blocking, that may leave long-lasting genetic signatures. However, a few studies have recently shown that climate may also play a role. We used red deer, a large, mobile herbivore that is assumed to be sensitive to climate change, to test hypotheses of possible selection on the mitochondrial DNA cytochrome b gene (mtDNA cytb) and competitive and/or density-blocking (using mtDNA control region)...
2016: PloS One
Valfrido Antonio Pereira-Filho, Luis Fernando de Gorla Oliveira, José Maurício Dos Santos Nunes Reis, Marisa Aparecida Cabrini Gabrielli, Rubens Spin Neto, Marcelo Silva Monnazzi
The aim of this study was to evaluate the mechanical behavior of different rigid fixation methods in mandible angle fractures. Three different plates were tested: one 4-hole grid miniplate, one 8-hole curved grid miniplate, and one 4-hole straight miniplate.For the loading tests, 30 polyurethane hemimandibles sectioned at the angle area to simulate a simple angle fracture were used: 10 hemimandibles for each group. The mechanical evaluation revealed that the straight plate positioned at the tension zone presented the best results in supporting vertical loading in the predefined displacement moments of 1, 3, and 5 mm...
October 2016: Journal of Craniofacial Surgery
Tarang Kumar Jain, Clayton N Wauneka, Wen Liu
BACKGROUND: Balance training has been shown to be effective in preventing ankle sprain recurrences in subjects with chronic ankle instability (CAI) but the biomechanical pathways underlying the clinical outcomes are still unknown. This study was conducted to determine if a 4-week balance training intervention can alter the mechanical characteristics in ankles with CAI. METHODS: Twenty-two recreationally active subjects with unilateral CAI were randomized to either a control (n = 11, 35...
2016: International Journal of Sports and Exercise Medicine
Christian Liebsch, Nicolas Graf, Hans-Joachim Wilke
PURPOSE: The influence of the anterior rib cage on the stability of the human thoracic spine is not completely known. One of the most common surgical interventions on the anterior rib cage is the longitudinal median sternotomy and its fixation by wire cerclage. Therefore, the purpose of this in vitro study was to examine, if wire cerclage can restore the stability of the human thoracic spine after longitudinal median sternotomy. METHODS: Six fresh frozen human thoracic spine specimens (C7-L1, 56 years in average, range 50-65), including the intact rib cage without intercostal muscles, were tested in a spinal loading simulator and monitored with an optical motion tracking system...
September 17, 2016: European Spine Journal
Claudio A González-Wevar, Sebastián Rosenfeld, Nicolás I Segovia, Mathias Hüne, Karin Gérard, Jaime Ojeda, Andrés Mansilla, Paul Brickle, Angie Díaz, Elie Poulin
Glacial episodes of the Quaternary, and particularly the Last Glacial Maximum (LGM) drastically altered the distribution of the Southern-Hemisphere biota, principally at higher latitudes. The irregular coastline of Patagonia expanding for more than 84.000 km constitutes a remarkable area to evaluate the effect of Quaternary landscape and seascape shifts over the demography of near-shore marine benthic organisms. Few studies describing the biogeographic responses of marine species to the LGM have been conducted in Patagonia, but existing data from coastal marine species have demonstrated marked genetic signatures of post-LGM recolonization and expansion...
2016: PloS One
Hailay Abrha Gesesew, Bosena Tebeje, Fessahaye Alemseged, Waju Beyene
BACKGROUND: Skill mix of health professionals, staff acquisition and turnover rate are among the major challenges for the delivery of quality health care. This study assessed the health workforce acquisition, retention, turnover rate and their intention to leave. METHODS: A cross-sectional survey with quantitative and qualitative data collection methods was conducted in Jimma Zone health institutions. Five years records (September 2009-August 2014) were reviewed to determine the turnover rate...
July 2016: Ethiopian Journal of Health Sciences
Florian Winkler, Amir H Tavabi, Juri Barthel, Martial Duchamp, Emrah Yucelen, Sven Borghardt, Beata E Kardynal, Rafal E Dunin-Borkowski
The phase and amplitude of the electron wavefunction that has passed through ultra-thin flakes of WSe2 is measured from high-resolution off-axis electron holograms. Both the experimental measurements and corresponding computer simulations are used to show that, as a result of dynamical diffraction, the spatially averaged phase does not increase linearly with specimen thickness close to an [001] zone axis orientation even when the specimen has a thickness of only a few layers. It is then not possible to infer the local specimen thickness of the WSe2 from either the phase or the amplitude alone...
July 30, 2016: Ultramicroscopy
Jessica L McKenzie, Rashpal S Dhillon, Patricia M Schulte
Steep genetic clines resulting from recent secondary contact between previously isolated taxa can either gradually erode over time or be stabilized by factors such as ecological selection or selection against hybrids. We used patterns of variation in 30 nuclear and two mitochondrial SNPs to examine the factors that could be involved in stabilizing clines across a hybrid zone between two subspecies of the Atlantic killifish, Fundulus heteroclitus. Increased heterozygote deficit and cytonuclear disequilibrium in populations near the center of the mtDNA cline suggest that some form of reproductive isolation such as assortative mating or selection against hybrids may be acting in this hybrid zone...
August 2016: Ecology and Evolution
Hadley L Sis, Erin M Mannen, Benjamin M Wong, Eileen S Cadel, Mary L Bouxsein, Dennis E Anderson, Elizabeth A Friis
Researchers have reported on the importance of the rib cage in maintaining mechanical stability in the thoracic spine and on the validity of a compressive follower preload. However, dynamic mechanical testing using both the rib cage and follower load has never been studied. An in vitro biomechanical study of human cadaveric thoracic specimens with rib cage intact in lateral bending, flexion/extension, and axial rotation under varying compressive follower preloads was performed. The objective was to characterize the motion and stiffness of the thoracic spine with intact rib cage and follower preload...
October 3, 2016: Journal of Biomechanics
Brice T Kamtchueng, Wilson Y Fantong, Mengnjo J Wirmvem, Rosine E Tiodjio, Alain F Takounjou, Jules R Ndam Ngoupayou, Minoru Kusakabe, Jing Zhang, Takeshi Ohba, Gregory Tanyileke, Joseph V Hell, Akira Ueda
With the use of conventional hydrogeochemical techniques, multivariate statistical analysis, and stable isotope approaches, this paper investigates for the first time surface water and groundwater from the surrounding areas of Lake Monoun (LM), West Cameroon. The results reveal that waters are generally slightly acidic to neutral. The relative abundance of major dissolved species are Ca(2+) > Mg(2+) > Na(+) > K(+) for cations and HCO3 (-) ≫ NO3 (-) > Cl(-) > SO4 (2-) for anions...
September 2016: Environmental Monitoring and Assessment
Yinghua Qiu, Chih-Yuan Lin, Preston Hinkle, Timothy S Plett, Crystal Yang, Jenu Varghese Chacko, Michelle A Digman, Li-Hsien Yeh, Jyh-Ping Hsu, Zuzanna S Siwy
Single pores in the resistive-pulse technique are used as an analytics tool to detect, size, and characterize physical as well as chemical properties of individual objects such as molecules and particles. Each object passing through a pore causes a transient change of the transmembrane current called a resistive pulse. In high salt concentrations when the pore diameter is significantly larger than the screening Debye length, it is assumed that the particle size and surface charge can be determined independently from the same experiment...
September 27, 2016: ACS Nano
Aurélie Pace, Raphaël Bourillot, Anthony Bouton, Emmanuelle Vennin, Serge Galaup, Irina Bundeleva, Patricia Patrier, Christophe Dupraz, Christophe Thomazo, Pierre Sansjofre, Yusuke Yokoyama, Michel Franceschi, Yannick Anguy, Léa Pigot, Aurélien Virgone, Pieter T Visscher
Microbialites are widespread in modern and fossil hypersaline environments, where they provide a unique sedimentary archive. Authigenic mineral precipitation in modern microbialites results from a complex interplay between microbial metabolisms, organic matrices and environmental parameters. Here, we combined mineralogical and microscopic analyses with measurements of metabolic activity in order to characterise the mineralisation of microbial mats forming microbialites in the Great Salt Lake (Utah, USA). Our results show that the mineralisation process takes place in three steps progressing along geochemical gradients produced through microbial activity...
2016: Scientific Reports
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