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https://www.readbyqxmd.com/read/28822943/sound-side-joint-contact-forces-in-below-knee-amputee-gait-with-an-esar-prosthetic-foot
#1
Mohammad Taghi Karimi, Firooz Salami, Amir Esrafilian, Daniel W W Heitzmann, Merkur Alimusaj, Cornelia Putz, Sebastian I Wolf
The incidence of knee and hip joint osteoarthritis in subjects with below knee amputation (BK) appears significantly higher compared to unimpaired subjects, especially in the intact side. However, it is controversial if constant higher loads on the sound side are one of the major factors for an increased osteoarthritis (OA) incidence in subjects with BK, beside other risk factors, e.g. with respect to metabolism. The aim wasto investigate joint contact forces (JCF) calculated by a musculoskeletal model in the intact side and to compare it with those of unimpaired subjects and to further elucidate in how far increased knee JCF are associated with increased frontal plane knee moments...
August 8, 2017: Gait & Posture
https://www.readbyqxmd.com/read/28821229/mechanisms-of-peripheral-phylogeographic-divergence-in-the-indo-pacific-lessons-from-the-spiny-lobster-panulirus-homarus
#2
Ahmad Farhadi, Andrew G Jeffs, Hamid Farahmand, Thankappan Sarasam Rejiniemon, Greg Smith, Shane D Lavery
BACKGROUND: There is increasing recognition of the concordance between marine biogeographic and phylogeographic boundaries. However, it is still unclear how population-level divergence translates into species-level divergence, and what are the principal factors that first initiate that divergence, and then maintain reproductive isolation. This study examines the likely forces driving population and lineage divergences in the broadly-distributed Indo-Pacific spiny lobster Panulirus homarus, which has peripheral divergent lineages in the west and east...
August 18, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28821041/regulation-of-structure-rheological-and-surface-properties-of-chitin-nanocrystal-dispersions
#3
M A Torlopov, I S Martakov, V I Mikhaylov, N V Tsvetkov, P V Krivoshapkin
The hydrosols of chitin nanocrystals (ChN) are promising as modifiers of properties, drug delivery systems, and media. The purpose of this work is to clarify the mechanisms for regulating processes of stability and structure formation occurring in the ChN hydrosols under the influence of varying ionic strength. ChN were isolated from the crab shell; ChN hydrosols are obtained with different concentrations of the dispersed phase. The structure and morphology of the particles was studied by atomic force microscopy and X-ray diffraction...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28819670/mimicking-wettability-alterations-using-temperature-gradients-for-water-nanodroplets
#4
Chirodeep Bakli, Sree Hari P D, Suman Chakraborty
A sessile droplet or a film usually moves from hotter regions to colder regions, due to variations in interfacial tension. This, known as the so-called Marangoni effect, is true for most pure liquids like water for which the surface tension decreases with an increase in temperature. In stark contrast to this existing understanding, we bring forth the coupled effect of wettability and temperature gradients on the dynamics of the three-phase contact line. By simultaneously tracking the dynamic evolution of the three-phase contact line due to the evaporation and diffusion of molecules through molecular dynamics simulations, we explore the coterminous effects of the change of surface tension coefficients and wetting parameters with temperature on sessile droplets residing on surfaces with different wettabilities...
August 18, 2017: Nanoscale
https://www.readbyqxmd.com/read/28818689/sol-gel-derived-hydroxyapatite-films-over-porous-calcium-polyphosphate-substrates-for-improved-tissue-engineering-of-osteochondral-like-constructs
#5
Whitaik David Lee, Rahul Gawri, Robert M Pilliar, William L Stanford, Rita A Kandel
Integration of in vitro-formed cartilage on a suitable substrate to form tissue-engineered implants for osteochondral defect repair is a considerable challenge. In healthy cartilage, a zone of calcified cartilage (ZCC) act as an intermediary for mechanical force transfer from soft to hard tissue, as well as an effective interlocking structure to better resist interfacial shear forces. We have developed biphasic constructs that consist of scaffold-free cartilage tissue grown in vitro on, and interdigitated with, porous calcium polyphosphate (CPP) substrates...
August 14, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28816914/congenital-hypotonia-in-toddlerhood
#6
Naomi Steiner, Alcy Torres, Arathi Reddy, Marilyn Augustyn
David is a 22-month-old boy who is new to your practice. He recently moved from a rural area in the Midwest. His father is in the United States Air Force, and his mother works as a full-time homemaker. Their household includes 5 older siblings. The family moves every year because of the father's Air Force placement.David was born full-term in Virginia, with no reported pregnancy complications and no alcohol, tobacco, or drug exposure. He was delivered vaginally, with Apgar scores of 7 and 9, respectively and no respiratory issues...
August 9, 2017: Journal of Developmental and Behavioral Pediatrics: JDBP
https://www.readbyqxmd.com/read/28816898/timing-of-postoperative-mechanical-loading-affects-healing-following-anterior-cruciate-ligament-reconstruction-analysis-in-a-murine-model
#7
Christopher L Camp, Amir Lebaschi, Guang-Ting Cong, Zoe Album, Camila Carballo, Xiang-Hua Deng, Scott A Rodeo
BACKGROUND: Following anterior cruciate ligament (ACL) reconstruction, the mechanical loading of the tissues has a significant impact on tendon-to-bone healing. The purpose of this study was to determine the effect of the timing of the initiation of mechanical loading on healing of a tendon graft in a bone tunnel. METHODS: ACL reconstruction using a flexor tendon autograft was performed in 56 mice randomized to 4 groups with differing times to initiation of postoperative mechanical loading: (1) immediate, (2) 5 days, (3) 10 days, or (4) 21 days following surgery...
August 16, 2017: Journal of Bone and Joint Surgery. American Volume
https://www.readbyqxmd.com/read/28816345/errors-in-calculating-a-p-tibial-contact-locations-in-total-knee-arthroplasty-using-3d-model-to-2d-image-registration-in-radiographs-an-in-vitro-study-of-two-methods
#8
Derrick Ross, Stephen Howell, Maury Hull
Knowledge of A-P tibial contact locations provides an objective assessment of the relative motion of the tibia on the femur following total knee arthroplasty, which can be used to compare the effects of different components, surgical techniques, and alignment goals on knee function in vivo. Both the closest point method and the penetration method have been used to calculate A-P tibial contact locations using 3D model-to-2D image registration. Because the errors in calculating the A-P tibial contact locations using these two methods are unknown, the primary purpose of this study was to determine these errors...
August 17, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/28815888/friction-and-wetting-transitions-of-magnetic-droplets-on-micropillared-superhydrophobic-surfaces
#9
Anas Al-Azawi, Mika Latikka, Ville Jokinen, Sami Franssila, Robin H A Ras
Reliable characterization of wetting properties is essential for the development and optimization of superhydrophobic surfaces. Here, the dynamics of superhydrophobicity is studied including droplet friction and wetting transitions by using droplet oscillations on micropillared surfaces. Analyzing droplet oscillations by high-speed camera makes it possible to obtain energy dissipation parameters such as contact angle hysteresis force and viscous damping coefficients, which indicate pinning and viscous losses, respectively...
August 16, 2017: Small
https://www.readbyqxmd.com/read/28815230/elastic-deformation-of-soft-coatings-due-to-lubrication-forces
#10
Yumo Wang, Matthew R Tan, Joelle Frechette
Elastic deformation of rigid materials with soft coatings (stratified materials) due to lubrication forces can alter the interpretation of dynamic surface forces measurements and prevent contact formation between approaching surfaces. Understanding the role of elastic deformation on the process of fluid drainage is necessary, in particular for the case where one (or both) of the interacting materials consists of a rigid substrate with a soft coating. We combine lubrication theory and solid linear elasticity to describe the dynamic of fluid drainage past a compliant stratified boundary...
August 17, 2017: Soft Matter
https://www.readbyqxmd.com/read/28814014/bio-inspired-control-of-joint-torque-and-knee-stiffness-in-a-robotic-lower-limb-exoskeleton-using-a-central-pattern-generator
#11
Stefan O Sobrade, Yannik Nager, Amy R Wu, Roger Gassert, Auke Ijspeert
Robotic lower limb exoskeletons are becoming increasingly popular in therapy and recreational use. However, most exoskeletons are still rather limited in their locomotion speed and the activities of daily live they can perform. Furthermore, they typically do not allow for a dynamic adaptation to the environment, as they are often controlled with predefined reference trajectories. Inspired by human leg stiffness modulation during walking, variable stiffness actuators increase flexibility without the need for more complex controllers...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813995/a-novel-human-effort-estimation-method-for-knee-assistive-exoskeletons
#12
Lorenzo Saccares, Anais Brygo, Ioannis Sarakoglou, Nikos G Tsagarakis
In this work we present a novel method to estimate online the torques at the knee joints with the goal to generate reference signals for knee assistive devices. One of the main advantages of the proposed approach is its reduced sensing requirements, which leads to an ergonomic setup with minimal instrumentation, especially above the knee and of the upper body. Indeed, only the measurement of the forces and torques exchanged between the ground and the user's feet, the posture of the shanks, and the model of the user's shank itself are needed for the estimation of the knee torque...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813868/relationship-between-assistive-torque-and-knee-biomechanics-during-exoskeleton-walking-in-individuals-with-crouch-gait
#13
Zachary F Lerner, Diane L Damiano, Thomas C Bulea
Crouch or "flexed knee" gait is a pathological gait pattern affecting many individuals with cerebral palsy. One proposed method to alleviate crouch is to provide robotic assistance to knee extension during walking. The purpose of this study was to evaluate how the magnitude of knee extensor torque affects knee kinematics, kinetics, and muscle activity. Motion capture, ground reaction force and electromyography data were collected while four participants with crouch gait from cerebral palsy walked with assistance from a novel robotic exoskeleton on an instrumented treadmill...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813855/an-optimized-design-of-a-parallel-robot-for-gait-training
#14
Marco Maddalena, Mozafar Saadat, Alireza Rastegarpanah, Rui C V Loureiro
The guidelines for enhancing robot-assisted training for post-stroke survivors head towards increasing exercise realism and variability; in particular lower limb rehabilitation needs the patient to feel challenged to adapt his locomotion and dynamic balance capabilities to different virtual ground scenarios. This paper proposes a design for a robot whose end-effector acts as a footplate to be in permanent contact with the user's foot during practice: the structure is such that it enables the user's foot to rotate around three axis, differently from what is currently available in the research for gait training; the parallel kinematic structure and the dimensional synthesis allow a suitable range of motion and aim at limiting device mass, footprint and reaction forces on the actuators when rendering virtual ground...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28812747/identifying-the-charge-generation-dynamics-in-cs-based-triple-cation-mixed-perovskite-solar-cells
#15
Manuel Salado, Ramesh K Kokal, Laura Calio, Samrana Kazim, Melepurath Deepa, Shahzada Ahmad
Triple cation based perovskite solar cells offer enhanced moisture tolerance and stability compared to mixed perovskites. Slight substitution of methyl ammonium or formamidinium cation by cesium (Cs(+)), was also reported to eliminate halide segregation due to its smaller size. To elucidate the device kinetics and understand the role of the Cs, we undertook different modes of scanning probe microscopy and electrochemical impedance spectroscopy (EIS) experiments. Kelvin probe force microscopy revealed that the incorporation of the Cs cation increases the contact potential difference (CPD), this CPD further increases when Spiro-OMeTAD is used as a hole transport material...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28812363/influence-of-oxygen-vacancies-on-the-frictional-properties-of-nanocrystalline-zinc-oxide-thin-films-in-ambient-conditions
#16
Huan-Pu Chang, En-De Chu, Yu-Ting Yeh, Yueh-Chun Wu, Fang-Yuh Lo, Wei-Hua Wang, Ming-Yau Chern, Hsiang-Chih Chiu
Oxygen vacancy is the most studied point defect and has been found to significantly influence the physical properties of zinc oxide (ZnO). By using atomic force microscopy (AFM), we show that the frictional properties on the ZnO surface at the nanoscale greatly depend on the amount of oxygen vacancies present in the surface layer and the ambient humidity. The photocatalytic effect (PCE) is used to qualitatively control the amount of oxygen vacancies in the surface layer of ZnO and reversibly switch the surface wettability between hydrophobic and superhydrophilic states...
August 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28811019/introducing-a-new-and-rapid-microextraction-approach-based-on-magnetic-ionic-liquids-stir-bar-dispersive-liquid-microextraction
#17
Alberto Chisvert, Juan L Benedé, Jared L Anderson, Stephen A Pierson, Amparo Salvador
With the aim of contributing to the development and improvement of microextraction techniques, a novel approach combining the principles and advantages of stir bar sorptive extraction (SBSE) and dispersive liquid-liquid microextraction (DLLME) is presented. This new approach, termed stir bar dispersive liquid microextraction (SBDLME), involves the addition of a magnetic ionic liquid (MIL) and a neodymium-core magnetic stir bar into the sample allowing the MIL coat the stir bar due to physical forces (i.e., magnetism)...
August 29, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28810760/a-thermodynamic-model-of-contact-angle-hysteresis
#18
Lasse Makkonen
When a three-phase contact line moves along a solid surface, the contact angle no longer corresponds to the static equilibrium angle but is larger when the liquid is advancing and smaller when the liquid is receding. The difference between the advancing and receding contact angles, i.e., the contact angle hysteresis, is of paramount importance in wetting and capillarity. For example, it determines the magnitude of the external force that is required to make a drop slide on a solid surface. Until now, fundamental origin of the contact angle hysteresis has been controversial...
August 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28809631/-comparison-between-the-range-of-movement-canine-real-cervical-spine-and-numerical-simulation-computer-model-validation
#19
R Srnec, Z Horák, R Sedláček, M Sedlinská, M Krbec, A Nečas
PURPOSE OF THE STUDY In developing new or modifying the existing surgical treatment methods of spine conditions an integral part of ex vivo experiments is the assessment of mechanical, kinematic and dynamic properties of created constructions. The aim of the study is to create an appropriately validated numerical model of canine cervical spine in order to obtain a tool for basic research to be applied in cervical spine surgeries. For this purpose, canine is a suitable model due to the occurrence of similar cervical spine conditions in some breeds of dogs and in humans...
2017: Acta Chirurgiae Orthopaedicae et Traumatologiae Cechoslovaca
https://www.readbyqxmd.com/read/28809485/dispersion-and-halogen-bonding-interactions-binding-of-the-axial-conformers-of-monohalo-and-%C3%A2-trans-1-2-dihalocyclohexanes-in-enantiopure-alleno-acetylenic-cages
#20
Cornelius Gropp, Tamara Husch, Nils Trapp, Markus Reiher, François Diederich
Enantiopure alleno-acetylenic cage (AAC) receptors with a resorcin[4]arene scaffold, from which four homochiral alleno-acetylenes converge to shape a cavity closed by a four-fold OH-hydrogen-bonding array, form a highly ordered porous network in the solid state. They enable the complexation and co-crystallization of otherwise non-crystalline small molecules. This paper analyzes the axial conformers of monohalo- and (±)-trans-1,2-dihalocyclohexanes, bound in the interior cavity of the AACs, on the atomic level in the solid state and in solution, accompanied by accurate calculations...
August 15, 2017: Journal of the American Chemical Society
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