Current Issue : October - December Volume : 2016 Issue Number : 4 Articles : 5 Articles
Due to the growing demand for assistance in rehabilitation therapies for handmovements, a robotic system is proposed to mobilize\nthe hand fingers in flexion and extension exercises. The robotic system is composed by four, type slider-crank, mechanisms that\nhave the ability to fit the user fingers length from the index to the little finger, through the adjustment of only one link for\neach mechanism. The trajectory developed by each mechanism corresponds to the natural flexoextension path of each finger.\nThe amplitude of the rotations for metacarpophalangeal joint (MCP) and proximal interphalangeal joint (PIP) varies from 0 to\n90âË?Ë? and the distal interphalangeal joint (DIP) varies from 0 to 60âË?Ë?; the joint rotations are coordinated naturally. The four RRRT\nmechanisms orientation allows a 15âË?Ë? abduction movement for index, ring, and little fingers. The kinematic analysis of this\nmechanism was developed in order to assure that the displacement speed and smooth acceleration into the desired range ofmotion\nand the simulation results are presented.The reconfiguration of mechanisms covers about 95% of hand sizes of a group ofMexican\nadult population. Maximum trajectory tracking error is less than 3% in full range of movement and it can be compensated by the\nadditional rotation of finger joints without injury to the user....
Bimodal atomic force microscopy uses a cantilever that is simultaneously driven at two of its eigenmodes (resonant modes). Parameters\nassociated with both resonances can be measured and used to extract quantitative nanomechanical information about the sample\nsurface. Driving the first eigenmode at a large amplitude and a higher eigenmode at a small amplitude simultaneously provides\nfour independent observables that are sensitive to the tipââ?¬â??sample nanomechanical interaction parameters. To demonstrate this, a\ngeneralized theoretical framework for extracting nanomechanical sample properties from bimodal experiments is presented based\non Hertzian contact mechanics. Three modes of operation for measuring cantilever parameters are considered: amplitude, phase,\nand frequency modulation. The experimental equivalence of all three modes is demonstrated on measurements of the second eigenmode\nparameters. The contact mechanics theory is then extended to power-law tip shape geometries, which is applied to analyze\nthe experimental data and extract a shape and size of the tip interacting with a polystyrene surface....
Nanowear and viscoelasticity were evaluated to study the nanotribological properties of lubricant films of Z-tetraol, D-4OH, and\nA20H, including their retention and replenishment properties. For A20H and thick Z-tetraol-coated disks, the disk surface partially\nprotrudes, and the phase lag (tan ...
Near-FieldOpticalMicroscopy is a valuable tool for the optical and topographic study of objects at a nanometric scale.Nanoparticles\nconstitute important candidates for such type of investigations, as they bear an important weight for medical, biomedical, and\nbiosensing applications. One, however, has to be careful as artifacts can be easily reproduced. In this study, we examined hybrid\nnanoparticles (or nanohybrids) in the near-field, while in solution and attached to gold nanoplots. We found out that they can be\nused for wavelength modulable near-field biosensors within conditions of artifact free imaging. In detail, we refer to the use of\ntopographic/optical image shift and the imaging of Local Surface Plasmon hot spots to validate the genuineness of the obtained\nimages. In summary, this study demonstrates a new way of using simple easily achievable comparative methods to prove the\nauthenticity of near-field images and presents nanohybrid biosensors as an application....
Silicon nanowires (SiNWs), fabricated via a top-down approach and then functionalized with\nbiological probes, are used for electrically-based sensing of breast tumor markers. The SiNWs,\nfeaturing memristive-like behavior in bare conditions, show, in the presence of biomarkers,\nmodified hysteresis and, more importantly, a voltage memory component, namely a voltage gap.\nThe voltage gap is demonstrated to be a novel and powerful parameter of detection thanks to its\nhigh-resolution dependence on charges in proximity of the wire. This unique approach of\nsensing has never been studied and adopted before. Here, we propose a physical model of the\nsurface electronic transport in Schottky barrier SiNW biosensors, aiming at reproducing and\nunderstanding the voltage gap based behavior. The implemented model describes well the\nexperimental Iââ?¬â??V characteristics of the device. It also links the modification of the voltage gap to\nthe changing concentration of antigens by showing the decrease of this parameter in response to\nincreasing concentrations of the molecules that are detected with femtomolar resolution in real\nhuman samples. Both experiments and simulations highlight the predominant role of the\ndynamic recombination of the nanowire surface states, with the incoming external charges from\nbio-species, in the appearance and modification of the voltage gap. Finally, thanks to its\ncompactness, and strict correlation with the physics of the nanodevice, this model can be used to\ndescribe and predict the Iââ?¬â??V characteristics in other nanostructured devices, for different than\nantibody-based sensing as well as electronic applications....
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