Multitendoned extrinsic muscles of the human hand can be divided into several neuromuscular compartments (NMCs), each of which contributes to the ability of human finger to produce independent finger movements or forc...
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ISBN:
(纸本)9781424441211
Multitendoned extrinsic muscles of the human hand can be divided into several neuromuscular compartments (NMCs), each of which contributes to the ability of human finger to produce independent finger movements or force. The aim of this study was to investigate the changes in the spatial activation of flexor digitorum superficialis (FDS) during the fingertip force production with non-invasive multichannel surface electromyography (sEMG) technique. 7 healthy Subjects were instructed to match the target force level for 5s using individual index finger (I), individual middle finger (M) and the combination of the index and middle finger (IM) respectively. Simultaneously, a 2×6 electrode array was employed to record multichannel sEMG from FDS as finger force was produced. The entropy and center of gravity of the sEMG root mean square (RMS) map were computed to assess the spatial inhomogeneity in muscle activation and the change in spatial distribution of EMG amplitude related to the force generation of specific task finger. The results showed that the area and intensity of high amplitude region increased with force production, and the entropy increased with force level under the same task finger. The findings indicate that the change of spatial distribution of multitendoned extrinsic hand muscle activation is correlated to specific biomechanical functions.
Effective exploitation of the application-specific parallel patterns and computation operations through their direct implementation in hardware is the base for construction of high-quality application-specific (re-) c...
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Here we report the fabrication of high conductive and large surface-area 3D pillar graphene nanostructures (PGN) films from assembly of vertically aligned CNT pillars on flexible copper foils and directly employed for...
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Here we report the fabrication of high conductive and large surface-area 3D pillar graphene nanostructures (PGN) films from assembly of vertically aligned CNT pillars on flexible copper foils and directly employed for the application in electrochemical double layer capacitance (EDLC) supercapacitor. The fabricated supercapacitor based on PGN films with excellent mechanical flexibility and electrical conductivity has high energy storage capability. The PGN films which were one-step synthesized on flexible copper foil (25 um) by CVD process exhibit high conductivity with sheet resistance as low as 1.6 ohm per square and high mechanical flexibility. The fabricated EDLC supercapacitor based on high surface-area PGN electrodes (563m 2 /g) shows high performance with high specific capacitance of 330F/g and energy density as high as 45.8Wh/kg. All of these make this 3D graphene/CNTs hybrid carbon nanostructures highly attractive material for high performance supercapacitor and other energy storage material.
Stimuli responsive hydrogels show a strong ability to change in volume with changes in selected environmental properties. This tendency of these hydrogels to change in volume is captured as pressure-change in confined...
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ISBN:
(纸本)9781424441211
Stimuli responsive hydrogels show a strong ability to change in volume with changes in selected environmental properties. This tendency of these hydrogels to change in volume is captured as pressure-change in confined cavities of pressure sensors. An array of pressure sensors on a single chip may carry hydrogels sensitive to multiple, selected metabolic markers and continuously monitor multiple vital parameters simultaneously. Currently, such sensors are capable of continuously monitoring pH, ionic strength, glucose levels and temperature in the sensor environment. In this paper, we report the effect of temperature changes on the performance of ionic strength sensor. A formulation of hydrogel that renders it sensitive to changes in ionic strength was UV polymerized in situ in piezoresistive pressure sensors with different membrane sizes. The sensor sensitivity, response time and stability are investigated as a function of temperature in vitro. The effect of temperature on these sensor characteristics is discussed.
The effect of surface passivation and crystallite size on the photoluminescence of porous silicon is reported. Oxygen-free porous silicon samples with medium to ultra high porosities have been prepared by using electr...
The effect of surface passivation and crystallite size on the photoluminescence of porous silicon is reported. Oxygen-free porous silicon samples with medium to ultra high porosities have been prepared by using electrochemical etching followed by photoassisted stain etching. As long as the samples were hydrogen-passivated the PL could be tuned from the red (750nm) to the blue (400nm) by increasing the porosity. We show that when surface oxidation occurred, the photoluminescence was red-shifted. For sizes smaller than 2.8nm, the red shift can be as large as 1eV but for larger sizes no shift has been observed. Comparing the experimental results with theoretical calculations, we suggest that the decrease in PL energy upon exposure to oxygen is related to recombination involving an electron or an exciton trapped in Si=O double bonds. This result clarifies the recombination mechanisms in porous silicon.
Chronic diseases, such as heart disease, diabetes, and obesity, have been linked with diet. Nutrient intake is also associated with diet. However, much of the research completed to elucidate these associations has not...
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We study the dynamics of tumor cell progression as growth factors and ionizing radiation (IR) combine to modify cellular microenvironments. Breast tumor growth depends on the behavior of cancer cells in their microenv...
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We study the dynamics of tumor cell progression as growth factors and ionizing radiation (IR) combine to modify cellular microenvironments. Breast tumor growth depends on the behavior of cancer cells in their microenvironment, and both components are affected by IR fractionation parameters. TGF-β1 promotes differentiation of fibroblasts to myofibroblasts, which stiffens the extracellular matrix (ECM) and promotes malignant cell phenotypes. IR generates reactive oxygen species (ROS) that damages and inactivates cells thus controlling proliferation. The effects of TGF-β1 and IR at various fraction sizes on ECM stiffness and fibroblast differenation are studied using MRC-5 fibroblasts in 3-D collagen cultures.
A new multiuser scheduling scheme is proposed and analyzed in this paper. The proposed system combines features of conventional full-feedback selection-based diversity systems and reduced-feedback switch-based diversi...
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ISBN:
(纸本)9781457713460
A new multiuser scheduling scheme is proposed and analyzed in this paper. The proposed system combines features of conventional full-feedback selection-based diversity systems and reduced-feedback switch-based diversity systems. The new hybrid system provides flexibility in trading-off the channel information feedback overhead with the prospected multiuser diversity gains. The users are clustered into groups, and the users' groups are ordered into a sequence. Per-group feedback thresholds are used and optimized to maximize the system overall achievable rate. The proposed hybrid system applies switched diversity criterion to choose one of the groups, and a selection criterion to decide the user to be scheduled from the chosen group. Numerical results demonstrate that the system capacity increases as the number of users per group increases, but at the cost of more required feedback messages.
The morphology of nanocrystalline (nc)-Si/amorphous (a)-SiO2 superlattices (SLs) is studied using Raman spectroscopy in the acoustic and optical phonon ranges, transmission electron microscopy (TEM), and atomic force ...
The morphology of nanocrystalline (nc)-Si/amorphous (a)-SiO2 superlattices (SLs) is studied using Raman spectroscopy in the acoustic and optical phonon ranges, transmission electron microscopy (TEM), and atomic force microscopy (AFM). It is demonstrated that high temperature annealing (up to 1100°C) and oxidation in O2/H2O ambient do not destroy the SL structure, which retains its original periodicity and nc-Si/a-SiO2 interface abruptness. It is found that oxidation at high temperatures reduces the defect density in nc-Si/a-SiO2 SLs and induces the lateral coalescence of Si nanocrystals (NCs). The size, shape, packing density, and crystallographic orientation of the Si nanocrystals are studied as a function of the oxidation time.
Dual spectral source assisted MOCVD is an ideal technique for the deposition of high dielectric constant materials as well as other electronic and optical materials. Tungsten halogen lamps and a deuterium lamp are use...
Dual spectral source assisted MOCVD is an ideal technique for the deposition of high dielectric constant materials as well as other electronic and optical materials. Tungsten halogen lamps and a deuterium lamp are used as the sources of optical and thermal energy. Ta2O5 films were deposited at 200°C for 30 minutes and annealed at 600°C for 30 minutes have shown leakage current densities as low as 10−10 A/ cm2 for gate voltage under 5V. To the best of our knowledge, these are the best results reported to date by other researchers. The high energy photons used in the in-situ cleaning and deposition process play an important role in obtaining high quality films of Ta2O5.
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