Generation of ultrashort electrical pulses in semiconductor waveguides

We report a novel device capable of generating ultrashort electrical pulses on a coplanar waveguide (CPW) by means of optical rectification. The device consists of a completely passive GaAs-based optical waveguide, which is velocity matched to a CPW line. Optical pulses are injected into the device and electrical pulses are collected at the output. Experimental results obtained in the laboratory show the potential of this device for high speed optical-to-electrical conversion

The effect of environmental index on mental health in nurses working in emergency and non emergency wards in Khorramabad hospitals

زمینه و هدف : یکی از دغدغه های ذهنی جوامع امروزی ، تامین سلامت و بهداشت روانی افراد به خصوص پرستاران است . پژوهش حاضر با هدف تعیین عوامل مرتبط با شاخص های محیط کار بر سلامت روان پرستاران شاغل در بیمارستان های شهر خرم آباد انجام گرفته است. روش بررسی: این یک مطالعه مقطعی است. جامعه آماری این پژوهش شامل کلیه پرستاران در بیمارستان مذکور که شامل 433 نفر و نمونه آماری شامل 207 نفر از پرستاران دو بخش بودند که در بیمارستان عشایر با روش نمونه گیری در دسترس و در بیمارستان تامین اجتماعی با روش سرشماری انتخاب شدند. ابزار جمع آوری اطلاعات عبارت بودند از : پرسشنامه اطلاعات جمعیت شناختی، پرسشنامه سلامت عمومی GHQ و نمره بندی تنش های محیط کار WES که پایایی و روایی آنها تایید شده است. برای آزمودن فرضیات از آزمون t مستقل ، تحلیل واریانس یک طرفه و ضریب همبستگی استفاده گردید. یافته ها : در تحقیق حاضر 119 زن و 88 مرد مورد مطالعه قرار گرفتند که 43.30 درصد پرستاران در بخش اورژانس و 57/69 درصد در سایر بخش ها مشغول به کار بودند. نتایج آزمون t مستقل نشان داد که تفاوت معناداری بین میانگین نمرات سلامت روان در پرستاران بخش اورژانس (71.14±19.29) در مقایسه با پرستاران سایر بخش ها (48.13±13.30) وجود ندارد (0.654=p). نتیجه گیری : ﭼﻨﺎن ﻛﻪ ﻧﺘﺎﻳﺞ مطالعه ﺣﺎﺿﺮ نشان می دهد ﻫﺮ ﭼﻨﺪ ﺷﺎﻏﻼن در ﺑﺨﺶ اورژاﻧﺲ ﺗﺮوﻣﺎی ﺑﻴﺸﺘﺮی را ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﺳﺎﺑﻘﻪ ی ﺣﻮادث ﺷﻐﻠﻲ ﺑﺮای ﺧﻮد و ﻫﻤﻜﺎرانشان تجربه کرده اند، تفاوت معنی داری بین اختلالات مرتبط با سلامت روان ناشی از فشار عصبی و روانی محیط کار در پرستاران بخش های اورژانس و غیر اورژانس در ﺑﻴﻤﺎرﺳﺘﺎن ﻳﺎﻓﺖ نشد

An extracellular/membrane bound S100P pool regulates motility and invasion of human extravillous trophoblast lines and primary cells

Whilst S100P has been shown to be a marker for carcinogenesis, we have shown, in non physio-pathological states, that its expression promotes trophoblast motility and invasion but the mechanisms explaining these cellular processes are unknown. Here we identify the presence of S100P in the plasma membrane/cell surface of all trophoblast cells tested, whether lines, primary extravillous (EVT) cells or section tissue samples using either biochemical purification ofplasma membrane material, cell surface protein isolation through biotinylation or microscopy analysis. Using extracellular loss of function studies, through addition of a specific S100P antibody, our work shows that inhibiting the cell surface/membrane-bound or extracellular S100P pools significantly reduces, but importantly only in part, both cell motility and cellular invasion in different trophoblastic cell lines, as well as primary EVTs. Interestingly, this loss in cellular motility/invasion did not result in changes to the overall actin organisation and focal adhesion complexes. These findings shed new light on at least two newly characterized pathways by which S100P promotes trophoblast cellular motility and invasion. One where cellular S100P levels involve the remodelling of focal adhesions whilst another, an extracellular pathway, appears to be focal adhesion independent. Both pathways could lead to the identification of novel targets that may explain why significant numbers of confirmed human pregnancies suffer complications through poor placental implantation

Zinc- and Copper-Doped Mesoporous Borate Bioactive Glasses: Promising Additives for Potential Use in Skin Wound Healing Applications

In this study, zinc (Zn)- and copper (Cu)-doped 13-93B3 borate mesoporous bioactive glasses (MBGs) were successfully synthesized using nitrate precursors in the presence of Pluronic P123. We benefited from computational approaches for predicting and confirming the experimental findings. The changes in the dynamic surface tension (SFT) of simulated body fluid (SBF) were investigated using the Du Noüy ring method to shed light on the mineralization process of hydroxyapatite (HAp) on the glass surface. The obtained MBGs were in a glassy state before incubation in SBF. The formation of an apatite-like layer on the SBF-incubated borate glasses was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The incorporation of Zn and Cu into the basic composition of 13-93B3 glass led to changes in the glass transition temperature (Tg) (773 to 556 °C), particle size (373 to 64 nm), zeta potential (−12 to −26 mV), and specific surface area (SBET) (54 to 123 m2/g). Based on the K-means algorithm and chi-square automatic interaction detection (CHAID) tree, we found that the SFT of SBF is an important factor for the prediction and confirmation of the HAp mineralization process on the glasses. Furthermore, we proposed a simple calculation, based on SFT variation, to quantify the bioactivity of MBGs. The doped and dopant-free borate MBGs could enhance the proliferation of mouse fibroblast L929 cells at a concentration of 0.5 mg/mL. These glasses also induced very low hemolysis (<5%), confirming good compatibility with red blood cells. The results of the antibacterial test revealed that all the samples could significantly decrease the viability of Pseudomonas aeruginosa. In summary, we showed that Cu-/Zn-doped borate MBGs can be fabricated using a cost-effective method and also show promise for wound healing/skin tissue engineering applications, as especially supported by the cell test with fibroblasts, good compatibility with blood, and antibacterial properties

Spin relaxation in (110) and (001) InAs/GaSb superlattices

We report an enhancement of the electron spin relaxation time (T1) in a (110) InAs/GaSb superlattice by more than an order of magnitude (25 times) relative to the corresponding (001) structure. The spin dynamics were measured using polarization sensitive pump probe techniques and a mid-infrared, subpicosecond PPLN OPO. Longer T1 times in (110) superlattices are attributed to the suppression of the native interface asymmetry and bulk inversion asymmetry contributions to the precessional D'yakonov Perel spin relaxation process. Calculations using a nonperturbative 14-band nanostructure model give good agreement with experiment and indicate that possible structural inversion asymmetry contributions to T1 associated with compositional mixing at the superlattice interfaces may limit the observed spin lifetime in (110) superlattices. Our findings have implications for potential spintronics applications using InAs/GaSb heterostructures.Comment: 4 pages, 2 figure

O-C Study of 545 Lunar Occultations from 13 Double Stars

International audienceIn this article, we have studied the reports of lunar occultations by this project observation's teams (named APTO) in comparison with other observations of the objects. Thirteen binary stars were selected for this study. All the previous observations of these stars were also collected. Finally, an analysis of O-C of all reports were performed

A performance analysis of tidal turbine conversion system based on control strategies

Energy efficient generation from renewable energy sources is of major concern nowadays. A horizontal axis marine current turbine (HAMCT) of diameter 1.9 m is modelled using the blade element momentum (BEM) scheme and the turbine output parameters are given as an input to the electrical system for a tip speed ratio (TSR) of 5 and a power coefficient of 0.4. The design aspects of a buck-boost converter with proportional integral (PI) and sliding mode controller (SMC) is investigated for HAMCT system, with the highest power output of about 15.6 kW for a water velocity of 3 m/s. A comparison between PI controller and SMC are analyzed for the tidal turbine conversion system to obtain the desired output voltage with high efficiency is discussed here. The dynamic variation on load side to be controlled with dual loop controller to regulate the output voltage and to optimize the input current. In this paper performance and resemblance of control techniques which include sliding mode controller and PI controller are analysed with step and bode plot response. The system is designed for an output voltage range of 0.38 kV to 2.4 kV which is suitable for DC microgrids. The performance of HAMCT coupled with PMSG and the power converter with a controller is modelled and designed under MATLAB/SIMULINK environment

Iranian joint registry (iranian national hip and knee arthroplasty registry)

Periodic evaluation and monitoring the health and economic outcome of joint replacement surgery is a common and popular process under the territory of joint registries in many countries. In this article we introduce the methodology used for the foundation of the National Iranian Joint Registry (IJR) with a joint collaboration of the Social Security Organization (SSO) and academic research departments considering the requirements of the Iran's Ministry of Health and Education. ©BY THE ARCHIVES OF BONE AND JOINT SURGERY