Mutual phase locking of a coupled laser diode-Gunn diode pair

Mutual phase locking has been achieved through series connection of a semiconductor laser and a Gunn diode oscillator. Experimental results obtained demonstrate a mutual interaction between the two oscillators which results in a short term Gunn diode oscillator stability and improved spectral purity of its output. We also observe a narrowing of laser pulses and an improvement in regularity

Variable frequency picosecond optical pulse generation from laser diodes by electrical feedback

High repetition rate picosecond optical pulse generation is achieved by providing electrical feedback (with and without external gain) to a self-pulsating laser diode. The feedback improves pulsation short-term stability (<25-kHz frequency jitter) and narrows the laser pulses (14 ps)

A monolithically integrated optical repeater

A monolithically integrated optical repeater has been fabricated on a single-crystal semi-insulating GaAs substrate. The repeater consists of an optical detector, an electronic amplifier, and a double heterostructure crowding effect laser. The repeater makes use of three metal semiconductor field effect transistors, one of which is used as the optical detector. With light from an external GaAlAs laser incident on the detector, an overall optical power gain of 10 dB from both laser facets was obtained

Two novel variants of hop stunt viroid associated with yellow corky vein disease of sweet orange and split bark disorder of sweet lime

Yellow corky vein was reported as a graft-transmissible disease of lime in India. It was attributed to infection by hop stunt viroid (HSVd) and citrus exocortis viroid (CEVd). Recently similar symptoms have been observed in Washington navel orange in Jahrom and Darab in the Fars province of Iran. It is characterized by yellowing and suberization of veins followed by tree decline. Sweet lime split bark is another disorder of increasing importance in the Fars province. It is characterized by cracks in the bark of the main stem which may spread to branches of the tree. Since these symptoms resembled those of certain viroids, a study was undertaken to determine possible association of viroids with the disorders. Reverse transcription polymerase chain reaction (RT-PCR) followed by cloning and sequencing of PCR products and dot-blot hybridization were used to identify the viroids associated with the diseases. Comparison of molecular properties (nucleotide composition, primary and secondary structures, molecular weights, phylogenetic relationships and percent nucleotide similarity and difference) of viroid variants were carried out. It was found that a novel variant of hop stunt viroid (HSVd-sycv) was associated with yellow corky vein disease of Washington navel and another new variant (HSVd-sb) with split bark disorder of sweet lime. No other viroids were constantly detected. HSVd-sycv was closely related to noncachexia variant of hop stunt viroid (HSVd-cit) but only with 93.7% homology with HSVd-lycv. It differed in a single nucleotide from HSVd-cit, in the variable domain in the so-called “cachexia expression motif”. HSVd-sb had only 94.8% homology with a noncachexia variant of hop stunt viroid (CVd-IIa-117) which causes mild bark-cracking symptoms on Pomeroy trifoliate orange rootstocks. According to the performed molecular comparisons, HSVd-sb differed from CVd-IIa-117 in “cachexia expression motif” and probably severe cracks induced by HSVd-sb occurred because of variation in this motif. Keyword: HSVd, Sweet lime split bark, Sweet orange yellow corky vein, Citrus viroids, Viroid phylogen

Direct adaptive fuzzy control of flexible-joint robots including actuator dynamics using particle swarm optimization

In this paper a novel direct adaptive fuzzy system is proposed to control flexible-joints robot including actuator dynamics. The design includes two interior loops: the inner loop controls the motor position using proposed approach while the outer loop controls the joint angle of the robot using a PID control law. One novelty of this paper is the use of a PSO algorithm for optimizing the control design parameters to achieve a desired performance. It is worthy of note that to form control law by considering practical considerations just the available feedbacks are used. It is beneficial for industrial applications wherethe real-time computation is costly. The proposed control approach has a fast response with a good tracking performance under the well-behaved control efforts. The stability is guaranteed in the presence of both structured and unstructured uncertainties. As a result, all system states are remained bounded. Simulation results on a two-link flexible-joint robot show the efficiency of the proposed scheme

Effects of ovarian varicose vein on mitochondrial structure, malondialdehyde and prooxidants - Antioxidants balance in rat ovaries Efectos de las Venas Ováricas Varicosas sobre la Estructura Mitocondrial, Niveles de Malondialdehído y Balance Prooxidantes-antioxidantes en Ovarios de Ratas

Oxidative stress is increased in varicose veins. Many studies have implicated oxidative stress in the pathogenesis of infertility causing diseases of the female reproductive tract. The aim of this study was to determine whether varicocele can cause raised levels of reactive oxygen species and denaturation of mitochondrial structure in ovaries of female rats or not. In each experimental study, 15 weaning-age female rats were divided equally in 3 groups: Unilateral Varicose Vein (A), Sham (B) and Control (C) groups. Mitochondrial structure and malondialdehyde levels as a product of lipid peroxidation and Prooxidants-Antioxidants Balance were evaluated 60 days after intervention in proestrus stage. Comparisons between groups were made by the measured test. After 2 months, our results showed that mitochondrial structure ultra-structurally was denatured with histologic examination, malondialdehyde and prooxidants-antioxidants balance levels of left ovaries increased significantly in varicocele group compared to control and sham groups (P�0.05). In the right side, malondialdehyde increased significantly, but in prooxidantsantioxidants balance levels, there is no significant differences between groups. The data of control and sham groups were the same. These findings may support the concept that increased levels of malondialdehyde and PAB in varicocele may cause negative effects on fertility, so using antioxidants maybe useful. © 2015, International Journal of Morphology. All rights reserved

The extracellular vesicles-derived from mesenchymal stromal cells: A new therapeutic option in regenerative medicine

ABSTRACT Mesenchymal stem cells (MSCs) are adult multipotent cells that due to their ability to homing to damaged tissues and differentiate into specialized cells, are remarkable cells in the field of regenerative medicine. It's suggested that the predominant mechanism of MSCs in tissue repair might be related to their paracrine activity. The utilization of MSCs for tissue repair is initially based on the differentiation ability of these cells; however now it has been revealed that only a small fraction of the transplanted MSCs actually fuse and survive in host tissues. Indeed, MSCs supply the microenvironment with the secretion of soluble trophic factors, survival signals and the release of extracellular vesicles (EVs) such as exosome. Also, the paracrine activity of EVs could mediate the cellular communication to induce cell- differentiation/self-renewal. Recent findings suggest that EVs released by MSCs may also be critical in the physiological function of these cells. This review provides an overview of MSC-derived extracellular vesicles as a hopeful opportunity to advance novel cell-free therapy strategies that might prevail over the obstacles and risks associated with the use of native or engineered stem cells. EVs are very stable; they can pass the biological barriers without rejection and can shuttle bioactive molecules from one cell to another, causing the exchange of genetic information and reprogramming of the recipient cells. Moreover, extracellular vesicles may provide therapeutic cargo for a wide range of diseases and cancer therapy. Key Words: Mesenchymal Stem Cells, Extracellular vesicles, Exosome, Regenerative medicine

RECK suppresses interleukin-17/TRAF3IP2-mediated MMP-13 activation and human aortic smooth muscle cell migration and proliferation

Sustained inflammation and matrix metalloproteinase (MMP) activation contribute to vascular occlusive/proliferative disorders. Interleukin-17 (IL-17) is a proinflammatory cytokine that signals mainly via TRAF3 Interacting Protein 2 (TRAF3IP2), an upstream regulator of various critical transcription factors, including AP-1 and NF-κB. Reversion inducing cysteine rich protein with kazal motifs (RECK) is a membrane-anchored MMP inhibitor. Here we investigated whether IL-17A/TRAF3IP2 signaling promotes MMP-13-dependent human aortic smooth muscle cell (SMC) proliferation and migration, and determined whether RECK overexpression blunts these responses. Indeed, IL-17A treatment induced (a) JNK, p38 MAPK, AP-1, NF-κB, and CREB activation, (b) miR-21 induction, (c) miR-27b and miR-320 inhibition, (d) MMP-13 expression and activation, (e) RECK suppression, and (f) SMC migration and proliferation, all in a TRAF3IP2-dependent manner. In fact, gain of TRAG3IP2 function, by itself, induced MMP-13 expression and activation, and RECK suppression. Furthermore, treatment with recombinant MMP-13 stimulated SMC migration in part via ERK activation. Importantly, RECK gain-of-function attenuated MMP-13 activity without affecting its mRNA or protein levels, and inhibited IL-17A- and MMP-13-induced SMC migration. These results indicate that increased MMP-13 and decreased RECK contribute to IL-17A-induced TRAF3IP2-dependent SMC migration and proliferation, and suggest that TRAF3IP2 inhibitors or RECK inducers have the potential to block the progression of neointimal thickening in hyperplastic vascular diseases