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https://www.readbyqxmd.com/read/28821661/attenuated-activity-across-multiple-cell-types-and-reduced-monosynaptic-connectivity-in-the-aged-perirhinal-cortex
#1
A P Maurer, S N Burke, K Diba, C A Barnes
The perirhinal cortex (PER), which is critical for associative memory and stimulus discrimination, has been described as a wall of inhibition between the neocortex and hippocampus. With advanced age, rats show deficits on PER-dependent behavioral tasks and fewer PER principal neurons are activated by stimuli, but the role of PER interneurons in these altered circuit properties in old age has not been characterized. In the present study, PER neurons were recorded while rats traversed a circular track bi-directionally in which the track was either empty or contained 8 novel objects evenly spaced around the track...
August 11, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28821242/methodological-factors-affecting-joint-moments-estimation-in-clinical-gait-analysis-a-systematic-review
#2
REVIEW
Valentina Camomilla, Andrea Cereatti, Andrea Giovanni Cutti, Silvia Fantozzi, Rita Stagni, Giuseppe Vannozzi
Quantitative gait analysis can provide a description of joint kinematics and dynamics, and it is recognized as a clinically useful tool for functional assessment, diagnosis and intervention planning. Clinically interpretable parameters are estimated from quantitative measures (i.e. ground reaction forces, skin marker trajectories, etc.) through biomechanical modelling. In particular, the estimation of joint moments during motion is grounded on several modelling assumptions: (1) body segmental and joint kinematics is derived from the trajectories of markers and by modelling the human body as a kinematic chain; (2) joint resultant (net) loads are, usually, derived from force plate measurements through a model of segmental dynamics...
August 18, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28819309/visualization-and-detection-of-ciliary-beating-pattern-and-frequency-in-the-upper-airway-using-phase-resolved-doppler-optical-coherence-tomography
#3
Joseph C Jing, Jason J Chen, Lidek Chou, Brian J F Wong, Zhongping Chen
Ciliary motion plays a critical role in the overall respiratory health of the upper airway. These cilia beat at a native frequency and in a synchronized pattern to continuously transport foreign particulate trapped in a layer of mucous out of the upper airway. Disruption of ciliary motion can lead to severe respiratory diseases and compromised respiratory function. Currently, the study of cilia requires expensive high speed cameras and high powered microscopes which is unsuitable for in vivo imaging and diagnosis...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28814611/homing-pigeons-columba-livia-modulate-wingbeat-characteristics-as-a-function-of-route-familiarity
#4
Lucy A Taylor, Steven J Portugal, Dora Biro
Mechanisms of avian navigation have received considerable attention, but whether different navigational strategies are accompanied by different flight characteristics is unknown. Managing energy expenditure is critical for survival; therefore, understanding how flight characteristics, and hence energy allocation, potentially change with birds' familiarity with a navigational task could provide key insights into the costs of orientation. We addressed this question by examining changes in the wingbeat characteristics and airspeed of homing pigeons (Columba livia) as they learned a homing task...
August 15, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28813992/review-of-the-actuators-of-active-knee-prostheses-and-their-target-design-outputs-for-activities-of-daily-living
#5
Dominik Simon Pieringer, Martin Grimmer, Michael Friedrich Russold, Robert Riener
Active prosthetic knees have the capability to provide net positive work, which is required in daily activities like stair and ramp negotiation or sit-to-stand transfers. Adding this capability might help to increase user mobility, safety, and independence. This article summarizes the biomechanical knee requirements for different activities of daily living and critically compares them with the actuator characteristics of state-of-the-art active prosthetic knee joints. As a result of a systematic literature research 22 active prosthetic knee joints were identified...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813975/a-lightweight-robotic-ankle-prosthesis-with-non-backdrivable-cam-based-transmission
#6
Tommaso Lenzi, Marco Cempini, Jeremy Newkirk, Levi J Hargrove, Todd A Kuiken
Below-knee level amputation significantly impacts the ability of an individual to ambulate. Transtibial amputees are typically prescribed energetically passive ankle-foot prostheses that behave as a spring or controlled damper, and therefore cannot fully replace the function of the missing limb. More recently, fully-powered devices have been proposed to more closely match the power generation ability of intact limbs. However, these fully-powered devices are significantly heavier than passive devices, thus increasing the stress on the socket-residual limb interface...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28809811/mutation-clusters-from-cancer-exome
#7
Zura Kakushadze, Willie Yu
We apply our statistically deterministic machine learning/clustering algorithm *K-means (recently developed in https://ssrn.com/abstract=2908286) to 10,656 published exome samples for 32 cancer types. A majority of cancer types exhibit a mutation clustering structure. Our results are in-sample stable. They are also out-of-sample stable when applied to 1389 published genome samples across 14 cancer types. In contrast, we find in- and out-of-sample instabilities in cancer signatures extracted from exome samples via nonnegative matrix factorization (NMF), a computationally-costly and non-deterministic method...
August 15, 2017: Genes
https://www.readbyqxmd.com/read/28806523/production-of-concentrated-pickering-emulsions-with-narrow-size-distributions-using-stirred-cell-membrane-emulsification
#8
Mohamed Soyeb Manga, David W York
Stirred cell membrane emulsification (SCME) has been employed to prepare concentrated Pickering oil in water emulsions solely stabilized by fumed silica nanoparticles. The optimal conditions under which highly stable and low polydispersity concentrated emulsions using the SCME approach are highlighted. Optimization of the oil flux rates and the paddle stirrer speeds are critical to achieving control over the droplet size and size distribution. Investigating the influence of oil volume fraction highlights the criticality of the initial particle loading in the continuous phase on the final droplet size and polydispersity...
August 14, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28806090/phonon-speed-not-scattering-differentiates-thermal-transport-in-lead-halide-perovskites
#9
Giselle A Elbaz, Wee-Liat Ong, Evan A Doud, Philip Kim, Daniel W Paley, Xavier Roy, Jonathan A Malen
Thermal management plays a critical role in the design of solid state materials for energy conversion. Lead halide perovskites have emerged as promising candidates for photovoltaic, thermoelectric, and optoelectronic applications, but their thermal properties are still poorly understood. Here, we report on the thermal conductivity, elastic modulus, and sound speed of a series of lead halide perovskites MAPbX3 (X = Cl, Br, I), CsPbBr3, and FAPbBr3 (MA = methylammonium, FA = formamidinium). Using frequency domain thermoreflectance, we find that the room temperature thermal conductivities of single crystal lead halide perovskites range from 0...
August 21, 2017: Nano Letters
https://www.readbyqxmd.com/read/28798840/a-microfluidic-device-for-isolation-and-characterization-of-transendothelial-migrating-cancer-cells
#10
Xin Cui, Weijin Guo, Yubing Sun, Baoce Sun, Shuhuan Hu, Dong Sun, Raymond H W Lam
Transendothelial migration of cancer cells is a critical stage in cancer, including breast cancer, as the migrating cells are generally believed to be highly metastatic. However, it is still challenging for many existing platforms to achieve a fully covering endothelium and to ensure transendothelial migration capability of the extracted cancer cells for analyses with high specificity. Here, we report a microfluidic device containing multiple independent cell collection microchambers underneath an embedded endothelium such that the transendothelial-migrated cells can be selectively collected from only the microchambers with full coverage of an endothelial layer...
January 2017: Biomicrofluidics
https://www.readbyqxmd.com/read/28797624/transcranial-direct-current-stimulation-over-multiple-days-enhances-motor-performance-of-a-grip-task
#11
Julie Fan, Julien Voisin, Marie-Hélène Milot, Johanne Higgins, Marie-Hélène Boudrias
BACKGROUND: Recovery of handgrip is critical after stroke since it is positively related to upper limb function. To boost motor recovery, transcranial direct current stimulation (tDCS) is a promising, non-invasive brain stimulation technique for the rehabilitation of persons with stroke. When applied over the primary motor cortex (M1), tDCS has been shown to modulate neural processes involved in motor learning. However, no studies have looked at the impact of tDCS on the learning of a grip task in both stroke and healthy individuals...
August 7, 2017: Annals of Physical and Rehabilitation Medicine
https://www.readbyqxmd.com/read/28783308/rotating-sleeve-triboelectric-electromagnetic-hybrid-nanogenerator-for-high-efficiency-of-harvesting-mechanical-energy
#12
Ran Cao, Tao Zhou, Bin Wang, Yingying Yin, Zuqing Yuan, Congju Li, Zhong Lin Wang
Currently, a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG) have been hybridized to effectively scavenge mechanical energy. However, one critical issue of the hybrid device is the limited output power due to the mismatched output impedance between the two generators. In this work, impedance matching between the TENG and EMG is achieved facilely through commercial transformers, and we put forward a highly integrated hybrid device. The rotating-sleeve triboelectric-electromagnetic hybrid nanogenerator (RSHG) is designed by simulating the structure of a common EMG, which ensures a high efficiency in transferring ambient mechanical energy into electric power...
August 7, 2017: ACS Nano
https://www.readbyqxmd.com/read/28780385/relationships-between-chewing-rate-occlusion-cephalometric-anatomy-muscle-activity-and-masticatory-performance
#13
Brent A Fulks, Kathryn X Callaghan, Claire D Tewksbury, Geoffrey E Gerstner
OBJECTIVE: Mastication consists of rhythmic jaw openings and closings. Recent studies suggest that muscle mechanical properties determine the rhythmic rate; however, speed-accuracy tradeoffs may also play a role. This study evaluated how variation in chewing rate affected chewing performance, how masticatory muscle activity varied with chewing rate, and whether morphology and demographics contributed to performance. DESIGN: Chewing performance and muscle activity were sampled in 23 healthy, fully-dentate adults, who chewed a standardized test food to a metronome set at 0...
July 29, 2017: Archives of Oral Biology
https://www.readbyqxmd.com/read/28777700/clinical-significance-of-us-artifacts
#14
Michael Baad, Zheng Feng Lu, Ingrid Reiser, David Paushter
Artifacts are frequently encountered at clinical US, and while some are unwanted, others may reveal valuable information related to the structure and composition of the underlying tissue. They are essential in making ultrasonography (US) a clinically useful imaging modality but also can lead to errors in image interpretation and can obscure diagnoses. Many of these artifacts can be understood as deviations from the assumptions made in generating the image. Therefore, understanding the physical basis of US image formation is critical to understanding US artifacts and thus proper image interpretation...
August 4, 2017: Radiographics: a Review Publication of the Radiological Society of North America, Inc
https://www.readbyqxmd.com/read/28773243/impact-load-behavior-between-different-charge-and-lifter-in-a-laboratory-scale-mill
#15
Zixin Yin, Yuxing Peng, Zhencai Zhu, Zhangfa Yu, Tongqing Li
The impact behavior between the charge and lifter has significant effect to address the mill processing, and is affected by various factors including mill speed, mill filling, lifter height and media shape. To investigate the multi-body impact load behavior, a series of experiments and Discrete Element Method (DEM) simulations were performed on a laboratory-scale mill, in order to improve the grinding efficiency and prolong the life of the lifter. DEM simulation hitherto has been extensively applied as a leading tool to describe diverse issues in granular processes...
July 31, 2017: Materials
https://www.readbyqxmd.com/read/28772581/water-impact-of-syntactic-foams
#16
Adel Shams, Sam Zhao, Maurizio Porfiri
Syntactic foams are particulate composite materials that are extensively integrated in naval and aerospace structures as core materials for sandwich panels. While several studies have demonstrated the potential of syntactic foams as energy absorbing materials in impact tests, our understanding of their response to water impact remains elusive. In this work, we attempt a first characterization of the behavior of a vinyl ester/glass syntactic subject to slamming. High-speed imaging is leveraged to elucidate the physics of water impact of syntactic foam wedges in a free-fall drop tower...
February 23, 2017: Materials
https://www.readbyqxmd.com/read/28772468/obtaining-cross-sections-of-paint-layers-in-cultural-artifacts-using-femtosecond-pulsed-lasers
#17
Takaaki Harada, Stephanie Spence, Athanasios Margiolakis, Skylar Deckoff-Jones, Rebecca Ploeger, Aaron N Shugar, James F Hamm, Keshav M Dani, Anya R Dani
Recently, ultrafast lasers exhibiting high peak powers and extremely short pulse durations have created a new paradigm in materials processing. The precision and minimal thermal damage provided by ultrafast lasers in the machining of metals and dielectrics also suggests a novel application in obtaining precise cross-sections of fragile, combustible paint layers in artwork and cultural heritage property. Cross-sections of paint and other decorative layers on artwork provide critical information into its history and authenticity...
January 26, 2017: Materials
https://www.readbyqxmd.com/read/28771570/multi-scale-approaches-for-high-speed-imaging-and-analysis-of-large-neural-populations
#18
Johannes Friedrich, Weijian Yang, Daniel Soudry, Yu Mu, Misha B Ahrens, Rafael Yuste, Darcy S Peterka, Liam Paninski
Progress in modern neuroscience critically depends on our ability to observe the activity of large neuronal populations with cellular spatial and high temporal resolution. However, two bottlenecks constrain efforts towards fast imaging of large populations. First, the resulting large video data is challenging to analyze. Second, there is an explicit tradeoff between imaging speed, signal-to-noise, and field of view: with current recording technology we cannot image very large neuronal populations with simultaneously high spatial and temporal resolution...
August 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28770315/parameters-for-stable-water-in-oil-lipiodol-emulsion-for-liver-trans-arterial-chemo-eembolization
#19
F Deschamps, L Moine, T Isoardo, L Tselikas, A Paci, L M Mir, N Huang, E Fattal, T de Baère
PURPOSE: Water-in-oil type and stability are important properties for Lipiodol emulsions during conventional trans-arterial chemo-embolization. Our purpose is to evaluate the influence of 3 technical parameters on those properties. MATERIALS AND METHODS: The Lipiodol emulsions have been formulated by repetitive back-and-forth pumping of two 10-ml syringes through a 3-way stopcock. Three parameters were compared: Lipiodol/doxorubicin ratio (2/1 vs. 3/1), doxorubicin concentration (10 vs...
August 2, 2017: Cardiovascular and Interventional Radiology
https://www.readbyqxmd.com/read/28766462/visual-correlates-of-fitness-to-drive-in-adults-with-multiple-sclerosis
#20
Sherrilene Classen, Sarah Krasniuk, Sarah A Morrow, Liliana Alvarez, Miriam Monahan, Tim Danter, Heather Rosehart
The impact of visual and visual-cognitive impairments on fitness to drive in persons with multiple sclerosis (PwMS) are not well studied. We quantified visual correlates of fitness to drive in 30 PwMS. PwMS completed visual ability and visual attention assessments, and a standardized on-road assessment, and were compared with 145 older volunteer drivers. PwMS (vs. older volunteer drivers) made more total ( W = 12,139, p = .03) and critical driving errors (predictive of crashes) in adjustment to stimuli ( W = 11,352, p < ...
August 1, 2017: OTJR: Occupation, Participation and Health
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