Szeg\"o kernel and symplectic aspects of spectral transform for extended spaces of rational matrices

We revisit the sympectic aspects of the spectral transform for matrix-valued rational functions with simple poles. We construct eigenvectors of such matrices in terms of the Szeg\"o kernel on the spectral curve. Using variational formulas for the Szeg\"o kernel we construct a new system of action-angle variables for the canonical symplectic form on the space of such functions. Comparison with previously known action-angle variables shows that the vector of Riemann constants is the gradient of some function on the moduli space of spectral curves; this function is found in the case of matrix dimension 2, when the spectral curve is hyperelliptic.Comment: 19 page

The simple approach to determination of active diffused phosphorus density in silicon

The diffusion of Phosphorus in silicon using a POCl₃ source has been considered. In the base of Fair-Tsai model of P-diffusion an empirical equation for calculation of active diffused phosphorus density (Qel), is proposed. In this equation, a relationship between (Qel), diffusion time, temperature and junction depth of P-diffused layer (Xj), is presented. The value of sheet resistance (Rs), which is taken from theoretical determination at 900°C, has a good agreement with experimental result

Simple facet joint repair with dynamic pedicular system: Technical note and case series

Purpose: Facet joints are important anatomical structures for the stability of spine. Surgical or degenerative damage to a facet joint may lead to spinal instability and causes clinical problems. This article explains the importance of facet joints, reviews facet replacement systems, and describes a simple and effective method for facet replacement after surgical removal of facet joints. Materials and Methods: Ten patients were operated with the diagnosis of unilateral nerve root compression secondary to facet degeneration. The hypertrophic facet joints were removed with microsurgical techniques and the roots were decompressed. Then, a unilateral artificial facet joint was created using two hinged screws and a dynamic rod. Results: The clinical outcome of all the patients was determined good or excellent at second and last follow-up (mean 13.3 months) controls using visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. Radiological evaluations also demonstrated no implant-related complications. Conclusions: The authors suggest that, if removal of a facet joint is necessary to decompress the nerve roots, the joint can be replaced by a construct composed of two hinged screws connected by a dynamic rod. This simple system mimics the function of a normal facet joint and is an effective technique for unilateral facet joint replacement

A facile route for preparation of CdS nanoparticles

CdS nanoparticles have been synthesized by a chemical reaction route using ethylenediamine as a complexing agent. The nanoparticles were characterized using techniques such as X-ray powder diffraction (XRD), scanning electron microscope (SEM), UV–VIS absorption spectroscopy, and photoluminescence spectroscopy. The absorption edge for the bulk hexagonal CdS is at 512 nm (2.42 eV). Comparing with the bulk CdS, it is believed that the blue shift in the absorption peak was caused by the quantum confinement effect. Photoluminescence measurements indicate CdS nanoparticles show fluorescence band with a maximum close to 315 nm

Anti-Acanthamoeba effects of silver and gold nanoparticles and contact lenses disinfection solutions

Background: This study aimed to investigate the anti-Acanthamoeba effects of the most used marketed disinfecting solutions in Iran. Moreover, the efficacy of some nano-compounds was tested against pathogenic Acanthamoeba. Methods: The present study was conducted in the School of Public Health, Tehran University of Medical sciences, Tehran, Iran during 2015-2016. Cysts of Acanthamoeba T4 genotype (7 x 104/ml) mixed at the equal volume with contact lens solutions including Opti-free, Ginza, ReNu, Maxima, Light, and Cyclean for the recommended time by the manufacturers. Nano-silver and nano-gold compounds were also treated with the amoebae. Chlorhexidine 0.02 and normal saline were used as positive and negative controls, respectively. Dead and alive amoebae were determined using vital stain and suspension was cultured in non-nutrient agar. The entire process was repeated at least three times. Results: In none of the solutions in the manufacturer's brochure recommended time, full cytotoxic effect was observed on the cysts of Acanthamoeba. Opti free express solution destroyed the cysts after 6 days. Nanosilver and nano-gold compounds showed no cytotoxic effect on the cysts of Acanthamoeba. Conclusion: None of the Nanoparticles compounds as well as contact lenses disinfecting solutions which studied was effective on Acanthamoeba cysts in the manufacturer's brochure recommended time. However, continuing study on Nano-silver and Nano-gold compounds to find effective ingredients against Acanthamoeba are highly recommended. © 2018, Tehran University of Medical Sciences (TUMS). All rights reserved

Template-based growth of TiO₂ nanorods by sol-gel process

In this paper, the preparation of TiO2 nanorods by sol-gel-template process has been considered. The prepared sols were characterized by using FTIR spectroscopy, and the obtained nanorods were characterized by X-ray diffraction and SEM microscopy. SEM images show that TiO2 nanorods with uniform diameter of about 100-200 nm and a length of several micrometers. The results of XRD indicated that the TiO₂ nanorods were crystallized in the anatase and rutile phases after annealing to 400-700 ºC up to 2 hours