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https://www.readbyqxmd.com/read/28821061/morphology-and-mechanical-properties-of-poly-%C3%AE-hydroxybutyrate-poly-%C3%AE%C2%B5-caprolactone-blends-controlled-with-cellulosic-particles
#1
Jianxiang Chen, Yuankun Wang, Zeren Yin, Kam C Tam, Defeng Wu
The rigid microcrystalline cellulose (MCC) particles and semi-rigid ethyl cellulose (EC) were used to control phase morphology and mechanical properties of immiscible poly(β-hydroxybutyrate) (PHB)/poly(ε-caprolactone) (PCL) blends. The interfacial properties were evaluated by the fiber retraction and contact angle methods MCC is incompatible with PHB and PCL, and dispersed independently in the two polymer phases in their blends. However, EC is more compatible with the two polymers, with a higher affinity for PCL...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28820488/phase-behaviour-and-miscibility-studies-of-collagen-silk-fibroin-macromolecular-system-in-dilute-solutions-and-solid-state
#2
Ima Ghaeli, Mariana A de Moraes, Marisa M Beppu, Katarzyna Lewandowska, Alina Sionkowska, Frederico Ferreira-da-Silva, Maria P Ferraz, Fernando J Monteiro
Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pairs through the detection of phase separation and improvement of the mechanical and physical properties of the blend. This study presents the formulation of a stable and one-phase mixture of collagen and regenerated silk fibroin (RSF), with the highest miscibility ratio between these two macromolecules, through inducing electrostatic interactions, using salt ions. For this aim, a ternary phase diagram was experimentally built for the mixtures, based on observations of phase behavior of blend solutions with various ratios...
August 18, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28820012/effect-of-rotational-prosthetic-alignment-variation-on-tibiofemoral-contact-pressure-distribution-and-joint-kinematics-in-total-knee-replacement
#3
Xin Xie, Roy Rusly, John D DesJardins, Frank Voss, Kim Chillag, Martine LaBerge
In total knee replacement surgery, implant alignment is one of the most important criteria for successful long-term clinical outcome. During total knee replacement implantation, femoral and tibial alignment are determined through appropriate bone resections, which could vary based on patient anatomy, implant design and surgical technique and further influence loading conditions and clinical outcomes. The current research focused on three critical alignment parameters for total knee replacement insertion: femoral component internal/external (I/E) rotation, varus-valgus tibiofemoral angulation and posterior tibial slope...
August 1, 2017: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
https://www.readbyqxmd.com/read/28819985/prediction-of-labor-outcome-using-serial-transperineal-ultrasound-in-the-first-stage-of-labor
#4
Chung Ming Chor, Liona Chiu Yee Poon, Tak Yeung Leung
OBJECTIVE: To evaluate the feasibility of predicting labor outcome using serial transperineal ultrasound (TPU) in the early active phase of labor. METHODS: This is a single center prospective observational study in a tertiary obstetrics unit in Hong Kong. Nulliparous women carrying singleton pregnancy at the onset of active phase of labor were recruited. Serial 3D volumes by TPU were acquired and then repeated after 1 and 2 hours, which were subsequently analyzed for fetal head symphyseal distance (HSD), angle of progression (AoP) and fetal head progression distance (PD)...
August 18, 2017: Journal of Maternal-fetal & Neonatal Medicine
https://www.readbyqxmd.com/read/28819151/the-investigation-of-stress-in-freestanding-gan-crystals-grown-from-si-substrates-by-hvpe
#5
Moonsang Lee, Dmitry Mikulik, Mino Yang, Sungsoo Park
We investigate the stress evolution of 400 µm-thick freestanding GaN crystals grown from Si substrates by hydride vapour phase epitaxy (HVPE) and the in situ removal of Si substrates. The stress generated in growing GaN can be tuned by varying the thickness of the MOCVD AlGaN/AlN buffer layers. Micro Raman analysis shows the presence of slight tensile stress in the freestanding GaN crystals and no stress accumulation in HVPE GaN layers during the growth. Additionally, it is demonstrated that the residual tensile stress in HVPE GaN is caused only by elastic stress arising from the crystal quality difference between Ga- and N-face GaN...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28818697/kinematic-differences-during-a-jump-cut-maneuver-between-individuals-with-and-without-a-concussion-history
#6
Andrew Lapointe, Luis Nolasco, Aniela Sosnowski, Eva Andrews, Douglas N Martini, Riann M Palmieri-Smith, Deanna H Gates, Steven P Broglio
Recent evidence suggests that athletes are at a higher risk of lower-body injuries in the months and years following a concussion. However, little is known about how people modify their movements post-concussion. This study examined kinematics during a jump cut motion in young adults with a concussion history (n=9; 4 males, 5 females; 3.1years' post-injury) and 10 controls (6 males, 4 females). Peak center of mass and peak knee angles during the landing phase of a jump-cut maneuver were evaluated. Participants with a concussion history demonstrated decreased knee varus (left: Mconc=-0...
August 14, 2017: International Journal of Psychophysiology
https://www.readbyqxmd.com/read/28818107/patellofemoral-kinematics-in-dogs-with-cranial-cruciate-ligament-insufficiency-an-in-vivo-fluoroscopic-analysis-during-walking
#7
Stanley E Kim, Geoffrey J Zann, Selena Tinga, Erica J Moore, Antonio Pozzi, Scott A Banks
BACKGROUND: Complete rupture of the cranial cruciate ligament (CrCL) in dogs causes profound disturbance to stifle joint biomechanics. The objective of this study was to characterize the effects of cranial cruciate ligament (CrCL) insufficiency on patellofemoral (PF) kinematics in dogs during walking. Ten client-owned dogs (20-40 kg) with natural unilateral complete CrCL rupture were included. Dogs underwent computed tomographic scans to create digital bone-models of the patella and femur...
August 17, 2017: BMC Veterinary Research
https://www.readbyqxmd.com/read/28817708/timing-and-extent-of-finger-force-enslaving-during-a-dynamic-force-task-cannot-be-explained-by-emg-activity-patterns
#8
Mojtaba Mirakhorlo, Huub Maas, DirkJan H E J Veeger
Finger enslaving is defined as the inability of the fingers to move or to produce force independently. Such finger enslaving has predominantly been investigated for isometric force tasks. The aim of this study was to assess whether the extent of force enslaving is dependent on relative finger movements. Ten right-handed subjects (22-30 years) flexed the index finger while counteracting constant resistance forces (4, 6 and 8 N) orthogonal to the fingertip. The other, non-instructed fingers were held in extension...
2017: PloS One
https://www.readbyqxmd.com/read/28816673/generating-arm-swing-trajectories-in-real-time-using-a-data-driven-model-for-gait-rehabilitation-with-self-selected-speed
#9
Babak Hejrati, Andrew S Merryweather, Jake J Abbott
Gait rehabilitation is often focused on the legs, and overlooks the role of the upper limbs. However, a variety of studies have demonstrated the importance of proper arm swing both during healthy walking and during rehabilitation. In this paper, we describe a method for generating proper arm-swing trajectories in real-time using only measurements of the angular velocity of a person's thighs, to be used during gait rehabilitation with self-selected walking speed. A datadriven linear time-invariant transfer function is developed, using frequency-response methods, which captures the frequencydependent magnitude and phase relationship between the thighs' angular velocities and the arm angles (measured at the shoulder, in the sagittal plane), using a data set of 30 healthy adult subjects...
August 14, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28816012/periodic-mesoporous-organosilica-films-with-a-tunable-steady-state-mesophase
#10
Murad A Redzheb, Sigrid Bernstorff, Barbara Sartori, Pascal Van Der Voort, Silvia Armini
The mesophase formation in spin-coated periodic mesoporous organosilica (PMO) films aged at a controlled ambient humidity is investigated by time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). The investigation demonstrates the existence of a tunable steady state in PMO spin-coated films. Thus, a film deposited at a relative humidity of 20 % has a lamellar mesophase, whereas a subsequent increase to 70 % leads to a phase transformation resulting in a P63 /mmc space group. On the other hand, an increase of the surfactant to organosilica molar ratio of between 0...
August 16, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28815603/registration-of-phase-contrast-images-in-propagation-based-x-ray-phase-tomography
#11
L Weber, A Hänsch, U Wolfram, A Pacureanu, P Cloetens, F Peyrin, S Rit, M Langer
X-ray phase tomography aims at reconstructing the 3D electron density distribution of an object. It offers enhanced sensitivity compared to attenuation-based X-ray absorption tomography. In propagation-based methods, phase contrast is achieved by letting the beam propagate after interaction with the object. The phase shift is then retrieved at each projection angle, and subsequently used in tomographic reconstruction to obtain the refractive index decrement distribution, which is proportional to the electron density...
August 16, 2017: Journal of Microscopy
https://www.readbyqxmd.com/read/28814776/continuously-wavelength-tunable-passband-flattened-fiber-comb-filter-based-on-polarization-diversified-loop-structure
#12
Jaehoon Jung, Yong Wook Lee
Continuous wavelength tuning of optical comb filters, which is an essential functionality for flexible signal processing in reconfigurable optical systems, has been challenging in high order filter structures with two birefringent elements (BEs) or more due to cumbersomeness in finding a combination of waveplates and BEs and complexity in determining their individual azimuthal orientations. Here, we propose a continuously tunable polarization-independent passband-flattened fiber comb filter with two BEs using a polarization-diversified loop structure for the first time...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28814064/electrical-properties-assessed-by-bioelectrical-impedance-spectroscopy-as-biomarkers-of-age-related-loss-of-skeletal-muscle-quantity-and-quality
#13
Yosuke Yamada, Bjoern Buehring, Diane Krueger, Rozalyn M Anderson, Dale A Schoeller, Neil Binkley
Skeletal muscle, in addition to being comprised of a heterogeneous muscle fiber population, also includes extracellular components that do not contribute to positive tensional force production. Here we test segmental bioelectrical impedance spectroscopy (S-BIS) to assess muscle intracellular mass and composition. S-BIS can evaluate electrical properties that may be related to muscle force production. Muscle fiber membranes separate the intracellular components from the extracellular environment and consist of lipid bilayers which act as an electrical capacitor...
September 1, 2017: Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
https://www.readbyqxmd.com/read/28814056/design-of-a-lightweight-tethered-torque-controlled-knee-exoskeleton
#14
Kirby Ann Witte, Andreas M Fatschel, Steven H Collins
Lower-limb exoskeletons show promise for improving gait rehabilitation for those with chronic gait abnormalities due to injury, stroke or other illness. We designed and built a tethered knee exoskeleton with a strong lightweight frame and comfortable, four-point contact with the leg. The device is structurally compliant in select directions, instrumented to measure joint angle and applied torque, and is lightweight (0.76 kg). The exoskeleton is actuated by two off-board motors. Closed loop torque control is achieved using classical proportional feedback control with damping injection in conjunction with iterative learning...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28814020/piecewise-and-unified-phase-variables-in-the-control-of-a-powered-prosthetic-leg
#15
Dario J Villarreal, David Quintero, Robert D Gregg
Many control methods have been proposed for powered prosthetic legs, ranging from finite state machines that switch between discrete phases of gait to unified controllers that have a continuous sense of phase. In particular, recent work has shown that a mechanical phase variable can parameterize the entire gait cycle for controlling a prosthetic leg during steady rhythmic locomotion. However, the unified approach does not provide voluntary control over non-rhythmic motions like stepping forward and back. In this paper we present a phasing algorithm that uses the amputee's hip angle to control both rhythmic and non-rhythmic motion through two modes: 1) a piecewise (PW) function that provides users voluntary control over stance and swing in a piecewise manner, and 2) a unified function that continuously synchronizes the motion of the prosthetic leg with the amputee user at different walking speeds...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813918/how-to-prepare-a-person-with-complete-spinal-cord-injury-to-use-surface-electrodes-for-fes-trike-cycling
#16
Raymond K Y Tong, Xiaojun Wang, Kenry W C Leung, Ginny T Y Lee, Cathy C Y Lau, H W Wai, Peter M K Pang, H C Leung
Functional Electrical Stimulation (FES) cycling could benefit people with Spinal Cord Injury (SCI). The FES cycling involves large muscle groups during the training, and thus improves the cardiovascular function, increases the muscle bulk and reduces the secondary complications. This study developed an outdoor FES exercise cycling system for complete SCI persons to exercise their lower limbs without putting extra load on upper extremities. The mechanical structure of the cycling system was specially redesigned to secure the SCI persons in the cycling system...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813865/template-model-inspired-leg-force-feedback-based-control-can-assist-human-walking
#17
Guoping Zhao, Maziar Sharbafi, Mark Vlutters, Edwin van Asseldonk, Andre Seyfarth
We present a novel control approach for assistive lower-extremity exoskeletons. In particular, we implement a virtual pivot point (VPP) template model inspired leg force feedback based controller on a lower-extremity powered exoskeleton (LOPES II) and demonstrate that it can effectively assist humans during walking. It has been shown that the VPP template model is capable of stabilizing the trunk and reproduce a human-like hip torque during the stance phase of walking. With leg force and joint angle feedback inspired by the VPP template model, our controller provides hip and knee torque assistance during the stance phase...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813839/timing-of-intermittent-torque-control-with-wire-driven-gait-training-robot-lifting-toe-trajectory-for-trip-avoidance
#18
Tamon Miyake, Yo Kobayashi, Masakatsu G Fujie, Shigeki Sugano
Gait training robots are useful for changing gait patterns and decreasing risk of trip. Previous research has reported that decreasing duration of the assistance or guidance of the robot is beneficial for efficient gait training. Although robotic intermittent control method for assisting joint motion has been established, the effect of the robot intervention timing on change of toe clearance is unclear. In this paper, we tested different timings of applying torque to the knee, employing the intermittent control of a gait training robot to increase toe clearance throughout the swing phase...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813820/design-of-an-exoskeleton-ankle-robot-for-robot-assisted-gait-training-of-stroke-patients
#19
Ling-Fung Yeung, Corinna Ockenfeld, Man-Kit Pang, Hon-Wah Wai, Oi-Yan Soo, Sheung-Wai Li, Kai-Yu Tong
Lower Limb Exoskeleton robot that can facilitate stair walking is a big challenge, most systems could only provide level ground walking. In this study, a lightweight (0.5kg at ankle, 0.5kg at waist for control box) and autonomous exoskeleton Ankle Robot was proposed to provide power assistance for gait training of chronic stroke patients and it can facilitate three walking conditions in real-time: (1) level walking, (2) stair ascending, and (3) stair descending. Chronic stroke patients (n=3) with drop foot gait deficit and moderate motor impairment were recruited to evaluate the system under different walking conditions (Functional Ambulatory Category: FAC=4...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28812351/structural-investigation-of-cesium-lead-halide-perovskites-for-high-efficiency-quantum-dot-light-emitting-diodes
#20
Quyet Van Le, Jong Beom Kim, Soo Young Kim, Byeongdu Lee, Dong Ryeol Lee
In this study, we have intensively investigated the effect of the reaction temperature of hot-injection method on the structural properties of CsPbX3 (X: Br, I, Cl) perovskite nanocrystals (NCs) using the small- and wide-angle X-ray scattering. Furthermore, light emitting diodes (LEDs) performance as well as photoluminescence characteristics for high-efficient LEDs is compared with reaction temperature. It is confirmed that the size of the NCs decreased as the reaction temperature decreased, resulting stronger quantum confinement...
August 16, 2017: Journal of Physical Chemistry Letters
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