Improved design for SOI based evanescently coupled multilayer spot-size converter

We report an improved version of a spot-size converter (SSC) consisting of a silicon nanowire evanescently coupled to a phase-matched Poly-Si multilayer structure. With wider transversal dimensions the multilayer structure expands the mode significantly thus increasing the coupling efficiency with the conventional single-mode fiber. Detailed optimization process of a 17-layer based SSC is discussed and its coupling efficiency with a high-NA fiber of radius 2 μm is obtained as 98% providing only 0.087 dB loss. Vertical alignment tolerance between the optimized SSC and a high-NA fiber of radius 2 μm is also shown. This novel design does not consist of a taper and can be fabricated by using CMOS compatible process. It has a short device length and more relaxed alignment tolerances with the fiber. Full-vectorial and computationally efficient finite element method and the least squares boundary residual method have been used for the analysis and optimization of the proposed structure

An overground robotic exoskeleton gait training in complete spinal cord injured patients

The use of robotic systems during the rehabilitation of spinal cord injured patients can contribute to achieve significant outcomes. The aim of this study is to investigate the effects of an overground robot-assisted gait training in complete spinal cord injured patients. Sixteen SCI patients (mean age: 35.3 ± 10.3 yrs) underwent 20 robot-assisted gait training sessions based on an overground robotic exoskeleton. The preliminary results of this study show that the robot-assisted gait training in complete SCI patients can improve patient-robot interaction

Abnormal distribution of AQP4 in minor salivary glands of primary Sjögren’s syndrome patients

A decreased saliva production occurs in primary Sjögren’s syndrome (pSS), an autoimmune disease characterized by oral and ocular dryness due to dysfunction of the lacrimal and salivary glands (SGs). Since water movement is involved in saliva secretion, the expression, localization and function of the water channels aquaporins (AQPs) have been extensively studied in SGs. To date, the presence of AQP4 remains controversial and ambiguous in human SGs. We investigated by immunohistochemistry, high-resolution confocal microscopy and quantitative image analysis, western blot and real-time RT-PCR, the presence of the AQP4 gene and the distribution of AQP4 protein in healthy controls and pSS SGs biopsies. Through the immunohistochemical analysis we demonstrated that AQP4 presence is confined to the basal region of acini, to the lateral and apical membrane of intercalated and striated ducts in both control and pSS glands. The most striking observation was the discovery of AQP4 localization in myoepithelial cells (MECs) that surround acini lobules and intercalated ducts, and the demonstration of AQP4-down-regulated immunoreactivity in pSS MECs. Our studies suggest that the capacity for water flow across the membrane of MECs may be altered in pSS, identifying AQP4 as a promising new therapeutic agent to treat xerostomi

Monte Carlo analysis of a control technique for a tunable white lighting system

A simulated colour control mechanism for a multi-coloured LED lighting system is presented. The system achieves adjustable and stable white light output and allows for system-to-system reproducibility after application of the control mechanism. The control unit works using a pre-calibrated lookup table for an experimentally realized system, with a calibrated tristimulus colour sensor. A Monte Carlo simulation is used to examine the system performance concerning the variation of luminous flux and chromaticity of the light output. The inputs to the Monte Carlo simulation, are variations of the LED peak wavelength, the LED rated luminous flux bin, the influence of the operating conditions, ambient temperature, driving current, and the spectral response of the colour sensor. The system performance is investigated by evaluating the outputs from the Monte Carlo simulation. The outputs show that the applied control system yields an uncertainty on the luminous flux of 2.5% within a 95% coverage interval which is a significant reduction from the 8% of the uncontrolled system. A corresponding uncertainty reduction in Δu´v´ is achieved from an average of 0.0193 to 0.00125 within 95% coverage range after using the control system