352 research outputs found

    Quantitative characteristics and chemical composition in Caspian roach (Rutilus rutilus caspicus) sperm

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    In this study, quantitative characteristics and chemical composition of in roach (Rutilus rutilus caspicus) sperm were investigated. Sperm traits included sperm movement duration, percentage of motile spermatozoa, sperm density, spermatocrit and sperm volume. Some seminal plasma characteristics (sodium, potassium, calcium, magnesium and chloride) were investigated. In addition, some metabolites of seminal plasma (glucose, cholesterol and protein) were measured. The Na+ and K+ ions correlated negatively with spermatozoa motility (r = -0.0518, p<.05 and r =-0.3597, p<.01) respectively. Also, there were significant positive correlations between Ca2+ and Cl- ions with spermatozoa motility (r = 0.2945, p<.05 and r= 0.1379, p<.01), respectively. Mg+2 was positively correlated with glucose and protein (r = 0.046, p<.05 and r = 0.694, p<.05), respectively. On the other hand, a significant positive relationship was found between Na+ and K+ (r = 0.548, p<.01). These parameters can be used to evaluation of sperm quality and collecting information about developing procedures for artificial fertilization of roach

    Antioxidative effects of tempol on mitochondrial dysfunction in diabetic nephropathy

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    Introduction. Oxidative stress has a well-known role in diabetic nephropathy, and mitochondria are the major source of reactive oxygen species production. This study aimed to assess the effect of tempol, a superoxide dismutase mimetic agent, on mitochondrial antioxidant enzymes and cell viability in diabetic nephropathy. Materials and Methods. Adult male Wistar rats were divided into 4 groups of 7 animals. Diabetes mellitus was induced by injection of streptozotocin in 2 groups, the rat in one of which were also treated with tempol for 4 weeks. Another group without diabetes mellitus received tempol, and the last group was the control. At the end of the treatment period, the kidney mitochondria were isolated and their antioxidant enzymes, including superoxide dismutase, glutathione peroxidase, and catalase were assessed. Malondialdehyde, total antioxidant capacity, and kidney cells viability were studied, as well. Results. The diabetic group was significantly different compared with the control group in malondialdehyde, catalase, and glutathione peroxidase activities. Superoxide dismutase and total antioxidative capacity did not show any significant differences among the four groups. Moreover, the diabetic group treated with tempol had significantly different glutathione peroxidase level and kidney cells viability, compared to the other diabetic group (P <.05) Conclusions. Diabetic nephropathy induces changes in mitochondrial antioxidative biomarkers and cells viability, some of which can be modified by tempol administration in rats. © 2018, Iranian Society of Nephrology. All rights reserved

    The effect of cations on sperm motility performance and fertilizing ability of silver carp Hypophtalmychtis molitrix

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    The objective of the study was to investigate the effect of saline solution containing cations (Na+, K+, Ca+2, Mg+2) on sperm motility performance (duration of sperm motility and percentage of motile spermatozoa) and fertilizing capacity of sperm (fertilization rate, hatching rate, larvae length during hatching, larvae length during active feeding and survival rate) in silver carp. The results suggested that solutions containing ions did not improve the duration of sperm motility. The same was observed for the percentage of motile spermatozoa. Fertilization rate influenced by solutions containing Ca+2, and other ions could not affect this parameter. The results showed that hatching rate was higher in solutions containing 99 mEq/L NaCl, 2 mEq/L MgCl2 and 2, 4 mEq/L CaCl2 respectively. Also, survival rate was higher in the solution containing 2 mEq/L MgCl2 and 36 mg/dL KCl respectively.With regard to the obtained results, it was concluded that using appropriate activation medium can improve quality of fish sperm and subsequently increases artificial reproduction performance

    The influence of ovarian fluid on the sperm physiology of Rutilus kutum

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    Motility parameters of the spermatozoa in most fish species spawning in fresh water like Rutilus kutum lasts for a short time after activation. Ovarian fluid significantly influenced sperm motility (motility duration period) and percent motility (progressive forward motile sperm). Both of these variables generally increased as the concentration of ovarian fluid increased from 33% to 50%, respectively. It is concluded that ovarian fluid enhances sperm movement in this species at appropriate level and thus has the potential to influence fertilization capacity

    The role of oxygen in the uptake of deuterium in lithiated graphite

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    We investigate the mechanism of deuterium retention by lithiated graphite and its relationship to the oxygen concentration through surface sensitive experiments and atomistic simulations. Deposition of lithium on graphite yielded 5%-8% oxygen surface concentration and when subsequently irradiated with D ions at energies between 500 and 1000 eV/amu and fluences over 10(16) cm(-2) the oxygen concentration rose to between 25% and 40%. These enhanced oxygen levels were reached in a few seconds compared to about 300 h when the lithiated graphite was allowed to adsorb oxygen from the ambient environment under equilibrium conditions. Irradiating graphite without lithium deposition, however, resulted in complete removal of oxygen to levels below the detection limit of XPS (e. g.

    Higher order correlations in a levitated nanoparticle phonon laser

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    We present theoretical and experimental investigations of higher order correlations of mechanical motion in the recently demonstrated optical tweezer phonon laser, consisting of a silica nanosphere trapped in vacuum by a tightly focused optical beam [R. M. Pettit et al., Nature Photonics 13, 402 (2019)]. The nanoparticle phonon number probability distribution is modeled with the master equation formalism in order to study its evolution across the lasing threshold. Up to fourth-order equal-time correlation functions are then derived from the probability distribution. Subsequently, the master equation is transformed into a nonlinear quantum Langevin equation for the trapped particle’s position. This equation yields the non-equal-time correlations, also up to fourth order. Finally, we present experimental measurements of the phononic correlation functions, which are in good agreement with our theoretical predictions. We also compare the experimental data to existing analytical Ginzburg-Landau theory where we find only a partial match

    Quantum to classical walk transitions tuned by spontaneous emissions

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    We have realized a quantum walk in momentum space with a rubidium spinor Bose-Einstein condensate by applying a periodic kicking potential as a walk operator and a resonant microwave pulse as a coin toss operator. The generated quantum walks appear to be stable for up to ten steps and then quickly transit to classical walks due to spontaneous emissions induced by laser beams of the walk operator. We investigate these quantum to classical walk transitions by introducing well-controlled spontaneous emissions with an external light source during quantum walks. Our findings demonstrate a scheme to control the robustness of the quantum walks and can also be applied to other cold atom experiments involving spontaneous emissions

    Light-shift-induced behaviors observed in momentum-space quantum walks

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    Over the last decade there have been many advances in studies of quantum walks (QWs) including a momentum-space QW recently realized in our spinor Bose-Einstein condensate system. This QW possessed behaviors that generally agreed with theoretical predictions; however, it also showed momentum distributions that were not adequately explained by the theory. We present a theoretical model which proves that the coherent dynamics of the spinor condensate is sufficient to explain the experimental data without invoking the presence of a thermal cloud of atoms as in the original theory. Our numerical findings are supported by an analytical prediction for the momentum distributions in the limit of zero-temperature condensates. This current model provides more complete explanations to the momentum-space QWs that can be applied to study quantum search algorithms and topological phases in Floquet-driven system

    The effect of opium addiction on arrhythmia following acute myocardial infarction

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    The effect of opium addiction on the appearance of different types of arrhythmias after acute myocardial infarction (AMI) has been assessed in few studies. This study is aimed to determine the effect of opium on post-MI arrhythmia and also to address the differences in the appearance of different types of arrhythmias after AMI between opium addicted and non-addicted patients. In this comparative study, participants were classified into two groups with opium addiction (n=94) and without opium addiction (n=106). Post-MI arrhythmias were determined among each group. Study populations were included all patients with first AMI admitted within 6 hours of the onset of chest pain to coronary care units (CCU) of two teaching hospitals affiliated to Kerman University of Medical Sciences (KUMS) in the city of Kerman, Iran. Opium addicted subjects had significantly more frequency of arrhythmia than non-opium addicted subjects (80.9 vs. 22.6, respectively; P<0.001). Opium addiction was a strong predictor for the occurrence of post-MI arrhythmias in two models of crude analysis (crude OR=14.4, P<0.001) and after adjusting for potential confounder factors (adjusted OR = 21.9, P<0.001). The prevalence of sinus tachycardia, sinus bradycardia and atrial fibrillation in opium addicts were significantly higher than non opium addicts (P<0.05). The results of our study showed that opium addiction is a potential and strong risk for occurring post-MI arrhythmias. © 2012 Tehran University of Medical Sciences. All rights reserved

    Metal Ion Implanted Compliant Electrodes in Dielectric Electroactive Polymer (EAP) Membranes

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    One of the key factors to obtain large displacements and high efficiency with dielectric electroactive polymer (DEAPs) actuators is to have compliant electrodes. Attempts to scale DEAPs down to the mm or micrometer range have encountered major difficulties, mostly due to the challenge of micropatterning sufficiently compliant electrodes. Simply evaporating or sputtering thin metallic films on elastomer membranes produces DEAPs whose stiffness is dominated by the metallic film. Low energy metal ion implantation for fabricating compliant electrodes in DEAPs presents several advantages: a) it is clean to work with, b) it does not add thick passive layers, and c) it can be easily patterned. We use this technology to fabricate DEAPs micro-actuators whose relative displacement is the same as for macro-scale DEAPs. With transmission electron microscope (TEM) we observed the formation of metallic clusters within the elastomer (PDMS) matrix, forming a nano-composite. We focus our studies on relating the properties of this nano-composite to the implantation parameters. We identified the optimal implantation parameters for which an implanted electrode presents an exceptional combination of high electrical conductivity and low compliance
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