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Aram Oh, Young Jin Sa, Hyeyoun Hwang, Hionsuck Baik, Jun Kim, Byeongyoon Kim, Sang Hoon Joo, Kwangyeol Lee
The rational design of highly efficient electrocatalysts for the hydrogen evolution reaction (HER) is of prime importance for establishing renewable and sustainable energy systems. The alkaline HER is particularly challenging as it involves a two-step reaction of water dissociation and hydrogen recombination, for which platinum-based binary catalysts have shown promising activity. In this work, we synthesized high performance platinum-nickel-cobalt alloy nanocatalysts for the alkaline HER through a simple synthetic route...
September 15, 2016: Nanoscale
Savvas J Constantinou, Ryan M Pace, A J Stangl, Lisa M Nagy, Terri A Williams
Wnt genes are a family of conserved glycoprotein ligands that play a role in a wide variety of cell and developmental processes, from cell proliferation to axis elongation. There are 13 Wnt subfamilies found among metazoans. Eleven of these appear conserved in arthropods with a pattern of loss during evolution of as many as six subfamilies among hexapods. Here we report on Wnt genes in the branchiopod crustacean, Thamnocephalus platyurus, including the first documentation of the expression of the complete Wnt gene family in a crustacean...
October 3, 2016: Evolution & Development
D B Amin, I M Lawless, D Sommerfeld, R M Stanley, B Ding, J J Costi
The complex, direction-dependent, poro-viscoelastic properties of the intervertebral disc (disc) suggest that investigations of the six degree of freedom (6DOF) behaviour may be susceptible to inter-test variation in mechanical response if the disc does not return to initial conditions between loading directions. No studies have quantified the effects of sequential multi-directional loading on the consistency of the compressive response of the disc throughout a 6DOF testing protocol. Therefore, the objective of this study was to determine the effect of 6DOF loading on the compressive properties (stiffness and phase angle) of human discs, as evaluated by a reference compression test performed after each single DOF test...
September 14, 2016: Journal of Biomechanics
Yaguang Zhu, Bo Jin, Yongsheng Wu, Tong Guo, Xiangmo Zhao
Aimed at solving the misplaced body trajectory problem caused by the rolling of semi-round rigid feet when a robot is walking, a legged kinematic trajectory correction methodology based on the Least Squares Support Vector Machine (LS-SVM) is proposed. The concept of ideal foothold is put forward for the three-dimensional kinematic model modification of a robot leg, and the deviation value between the ideal foothold and real foothold is analyzed. The forward/inverse kinematic solutions between the ideal foothold and joint angular vectors are formulated and the problem of direct/inverse kinematic nonlinear mapping is solved by using the LS-SVM...
2016: Sensors
Andres Espinal, Horacio Rostro-Gonzalez, Martin Carpio, Erick I Guerra-Hernandez, Manuel Ornelas-Rodriguez, Marco Sotelo-Figueroa
This paper presents a method to design Spiking Central Pattern Generators (SCPGs) to achieve locomotion at different frequencies on legged robots. It is validated through embedding its designs into a Field-Programmable Gate Array (FPGA) and implemented on a real hexapod robot. The SCPGs are automatically designed by means of a Christiansen Grammar Evolution (CGE)-based methodology. The CGE performs a solution for the configuration (synaptic weights and connections) for each neuron in the SCPG. This is carried out through the indirect representation of candidate solutions that evolve to replicate a specific spike train according to a locomotion pattern (gait) by measuring the similarity between the spike trains and the SPIKE distance to lead the search to a correct configuration...
2016: Frontiers in Neurorobotics
González Ezequiel, Adriana Salvo, Graciela Valladares
Human activities have led to global simplification of ecosystems, among which Neotropical dry forests are some of the most threatened. Habitat loss as well as edge effects may affect insect communities. Here, we analyzed insects sampled with pan traps in nine landscapes (at five scales, in 100-500m diameter circles) comprising cultivated fields and Chaco Serrano forests, at overall community and taxonomic order level. In total 7043 specimens and 456 species of hexapods were captured, with abundance and richness being directly related to forest cover at 500 m and higher at edges in comparison with forest interior...
July 22, 2016: Insect Science
A Espinal, H Rostro-Gonzalez, M Carpio, E I Guerra-Hernandez, M Ornelas-Rodriguez, H J Puga-Soberanes, M A Sotelo-Figueroa, P Melin
A bioinspired locomotion system for a quadruped robot is presented. Locomotion is achieved by a spiking neural network (SNN) that acts as a Central Pattern Generator (CPG) producing different locomotion patterns represented by their raster plots. To generate these patterns, the SNN is configured with specific parameters (synaptic weights and topologies), which were estimated by a metaheuristic method based on Christiansen Grammar Evolution (CGE). The system has been implemented and validated on two robot platforms; firstly, we tested our system on a quadruped robot and, secondly, on a hexapod one...
2016: Computational Intelligence and Neuroscience
Shigetaka Nishiguchi, Akira Yagi, Nobuaki Sakai, Hiroki Oda
Homophilic binding of E-cadherins through their ectodomains is fundamental to epithelial cell-cell adhesion. Despite this, E-cadherin ectodomains have evolved differently in the vertebrate and insect lineages. Of the five rod-like, tandemly aligned extracellular cadherin domains of vertebrate E-cadherin, the tip extracellular cadherin domain plays a pivotal role in binding interactions. Comparatively, the six consecutive N-terminal extracellular cadherin domains of Drosophila E-cadherin, DE-cadherin (also known as Shotgun), can mediate adhesion; however, the underlying mechanism is unknown...
September 1, 2016: Journal of Cell Science
Jinglei Zhao, Huayan Pu, Jun Zou, Yi Sun, Shugen Ma
A novel eccentric paddle mechanism based on the epicyclic gear mechanism (ePaddle-EGM) has been proposed to enhance the mobility of amphibious robot for multi-terrain tasks with diverse locomotion gaits. This paper presents a brief description for this mechanism. Based on the feature of ePaddle-EGM, a unique non-reciprocating legged gait planning method is proposed. This method could minimize the negative effect of backlash between gear mesh in the epicyclic gear mechanism. Furthermore, the stable tripod gait for the ePaddle-EGM-based hexapod robot is designed...
2016: Robotics and Biomimetics
Farhat Nosheen, Bing Ni, Xiaobin Xu, Haozhou Yang, Zhicheng Zhang, Xun Wang
Several intricate Pt-Cu alloy architectures have been synthesized including hexapod backbones with stretchers and caved octahedron like hexapods, as well as some other intermediates with complex structures. The mechanistic study indicates that the shape is realized via a competitive effect between etching and growth induced by different chemicals.
July 21, 2016: Nanoscale
Dhara B Amin, Dana Sommerfeld, Isaac M Lawless, Richard M Stanley, Boyin Ding, John J Costi
While the effects of disc degeneration on compression and rotation motions have been studied, there is no data for shear loading. Clinical research has shown that those with low back pain (a potential consequence of degeneration) experience a 75% greater lateral shear force than those without it. Therefore, the aim was to compare the effect of degeneration on spine segment stiffness and phase angle in each of six degree of freedom (6DOF) loading directions. Fourteen intact functional spinal units (FSU) were dissected from human lumbar spines (mean (SD) age 76...
August 2016: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
Sanpon Vantasin, Wei Ji, Yoshito Tanaka, Yasutaka Kitahama, Mengfan Wang, Kanet Wongravee, Harnchana Gatemala, Sanong Ekgasit, Yukihiro Ozaki
3D surface-enhanced Raman scattering (SERS) imaging with highly symmetric 3D silver microparticles as a SERS substrate was developed. Although the synthesis method is purely chemical and does not involve lithography, the synthesized nanoporous silver microparticles possess a regular hexapod shape and octahedral symmetry. By using p-aminothiophenol (PATP) as a probe molecule, the 3D enhancement patterns of the particles were shown to be very regular and predictable, resembling the particle shape and exhibiting symmetry...
July 11, 2016: Angewandte Chemie
N Ferreira, L C Marais
Femoral non-unions are difficult to treat even for the experienced orthopaedic trauma surgeon. If the non-union follows failure of modern stable internal fixation, the complexity of the management is further increased. We report two cases of stiff hypertrophic femoral non-unions after failed locking plate fixation that were successfully treated with a new hexapod circular external fixator. In addition to providing the necessary stability for functional rehabilitation and union, the hexapod circular fixator software allows gradual correction of deformities in order to restore the normal mechanical alignment of the limb...
August 2016: Strategies in Trauma and Limb Reconstruction
Fayez Elkholy, Falko Schmidt, Rudolf Jäger, Bernd G Lapatki
OBJECTIVE: To evaluate whether overloading of teeth can be avoided by utilizing aligners with reduced thicknesses of 0.4 mm or 0.3 mm. MATERIALS AND METHODS: The experimental setup included an acrylic maxillary jaw model with tooth 11 separated and fixed via a 3-D force-moment transducer to a hexapod for experimental movement. Aligners tested were fabricated on duplicate stone models using commercially available polyethylene terephthalate glycol (PET-G) foils with thicknesses between 0...
May 25, 2016: Angle Orthodontist
Andrew Hughes, Michael Parry, Nima Heidari, Mark Jackson, Roger Atkins, Fergal Monsell
We describe the intraoperative use of the Taylor Spatial Frame to correct complex multiplanar deformities of the tibia before definitive internal stabilization using minimally invasive techniques. Thirteen consecutive procedures were performed in 12 patients. All deformities of the tibia were assessed with standardized radiographs allowing estimation of the center of rotation of angulation (CORA) or multiple CORA for multiplanar deformities. The cause of the deformity included both posttraumatic and metabolic conditions...
July 2016: Journal of Orthopaedic Trauma
Christopher A Iobst
Most tibia fractures in children can be treated nonoperatively. For fractures that do require surgery, however, the most common methods of management include plating or flexible nail insertion. Some fracture patterns, such as periphyseal fractures, fractures with bone and/or soft tissue loss, or fractures with delayed presentation, are not easily amenable to these techniques. Hexapod external fixators are especially helpful in these difficult cases. The purpose of this review is to discuss the principles of performing hexapod circular external fixation applied to pediatric tibia fractures...
June 2016: Journal of Pediatric Orthopedics
Istabrak Hasan, Friedhelm Heinemann, Monika Schwegmann, Ludger Keilig, Helmut Stark, Christoph Bourauel
Small diameter (mini) dental implants have become more popular in recent years as alternatives to classical implant treatment in clinical cases with critical bony situations. However, an in-depth scientific analysis of the mechanical and biomechanical effects of small diameter implants has not yet been published. The aim of the present study was to investigate experimentally different commercial mini implants by measuring their displacements under immediate loading. Twelve commercially available mini implants were measured...
April 12, 2016: Biomedizinische Technik. Biomedical Engineering
Walan Grizolli, Joakim Laksman, Franz Hennies, Brian Norsk Jensen, Ralf Nyholm, Rami Sankari
A high precision five rotation-axes polarimeter using transmission multilayers as polarizers and reflection multilayers as analyzers has been designed and manufactured. To cover the extreme ultraviolet regime, Mo/Si, Cr/C, Sc/Cr, and W/B4C multilayers for transmission and reflection have also been designed and produced. The polarimeter mechanics is supported on a hexapod to simplify the alignment relative to photon beam. The instrument is designed so that it can be easily transferred between different beamlines...
February 2016: Review of Scientific Instruments
Christian Derst, Heinrich Dircksen, Karen Meusemann, Xin Zhou, Shanlin Liu, Reinhard Predel
BACKGROUND: Neuropeptides are key players in information transfer and act as important regulators of development, growth, metabolism, and reproduction within multi-cellular animal organisms (Metazoa). These short protein-like substances show a high degree of structural variability and are recognized as the most diverse group of messenger molecules. We used transcriptome sequences from the 1KITE (1K Insect Transcriptome Evolution) project to search for neuropeptide coding sequences in 24 species from the non-pterygote hexapod lineages Protura (coneheads), Collembola (springtails), Diplura (two-pronged bristletails), Archaeognatha (jumping bristletails), and Zygentoma (silverfish and firebrats), which are often referred to as "basal" hexapods...
2016: BMC Evolutionary Biology
F Birkholtz, N Ferreira
Circular external fixators, and in particular hexapod circular external fixators, are increasingly being used in orthopaedic traumatology and limb reconstruction. Their ability to provide three dimensional stability throughout the treatment period make these external fixators indispensable in the management of complex reconstructive work. This study has identified a unique mode of failure with the use of Taylor Spatial Frame Fast-Fx struts and termed this complication catastrophic strut collapse. In this article a lab model is used to demonstrate the consequences of catastrophic strut collapse and warn users of the importance of using the ID bands and locking nuts to prevent inadvertent fragment displacement...
2016: Journal of Medical Engineering & Technology
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