Synergistic study on electrochemically deposited thin film with a spectrum from micro to nano range structures

Thin films are deposited onto bulk materials (substrates) to achieve properties unattainable or not easily attainable in the substrates alone. The film thickness usually varies from few nanometers to a maximum value of 1 μm. Cavitation, irradiation of liquid with high intensity ultrasound, as a means of altering the crystallization process is achieved by the repeated creation and collapse of microscopic bubbles inside the solution. It is at the solid-liquid interface that electrochemical techniques may be employed to detect the possible influence of sonication on electrochemical nucleation and growth of clusters. In this work we prepare the copper thin film by sonoelectrosynthesis method at different temperature, acid and concentration of electrolyte. Films are characterized by XRD, SEM, AFM, and study of the mechanical properties is done by nanaoidentation. Scahifker and Hills model was used for study of nucleation and growth phenomena for electrochemically deposited thin film by cyclic voltammetry and chronoamperometry. A potential of 450 mV (100 mV negative than the Nernst potential) was selected for the deposition procedure for all the conditions. The sole impact of sonication was experimented before the study of the coupling effect and was found to favor nucleation ahead of growth. The evidence of secondary nucleation in ultrasonic condition was also observed. The thickness of films lies in the range of 400-500 nm. The phases of the deposits are confirmed by the XRD analysis. The nucleation population density got increased from a low value to high value of acid concentrations. Comparison with the theoretical models, it is apparent that copper follows progressive nucleation mode in increasing acid concentration. Hydrogen evolution was also imperative at increasing acid concentrations, however, ultrasound capable of degassing produced hydrogen free adherent surfaces. The facts are also confirmed by the morphological analysis by SEM and AFM. The same trend is observed for the films with low temperatures. Among all the depositions copper films at – 4 °C is the smoothest. Increasing metal ion concentrations produces finer and harder deposits. Films are rougher at 0.1 M as compared to that of 0.025 M. The grains are found to vary from 400 nm to 50 nm at various conditions with the average roughness factors from 300 nm to 14 nm

Critical Role of IRF-5 in the Development of T helper 1 responses to Leishmania donovani infection

The transcription factor Interferon Regulatory Factor 5 (IRF-5) has been shown to be involved in the induction of proinflammatory cytokines in response to viral infections and TLR activation and to play an essential role in the innate inflammatory response. In this study, we used the experimental model of visceral leishmaniasis to investigate the role of IRF-5 in the generation of Th1 responses and in the formation of Th1-type liver granulomas in Leishmania donovani infected mice. We show that TLR7-mediated activation of IRF-5 is essential for the development of Th1 responses to L. donovani in the spleen during chronic infection. We also demonstrate that IRF-5 deficiency leads to the incapacity to control L. donovani infection in the liver and to the formation of smaller granulomas. Granulomas in Irf5-/- mice are characterized by an increased IL-4 and IL-10 response and concomitant low iNOS expression. Collectively, these results identify IRF-5 as a critical molecular switch for the development of Th1 immune responses following L. donovani infections and reveal an indirect role of IRF-5 in the regulation of iNOS expression

Critical Role of IRF-5 in the Development of T helper 1 responses to Leishmania donovani infection

The transcription factor Interferon Regulatory Factor 5 (IRF-5) has been shown to be involved in the induction of proinflammatory cytokines in response to viral infections and TLR activation and to play an essential role in the innate inflammatory response. In this study, we used the experimental model of visceral leishmaniasis to investigate the role of IRF-5 in the generation of Th1 responses and in the formation of Th1-type liver granulomas in Leishmania donovani infected mice. We show that TLR7-mediated activation of IRF-5 is essential for the development of Th1 responses to L. donovani in the spleen during chronic infection. We also demonstrate that IRF-5 deficiency leads to the incapacity to control L. donovani infection in the liver and to the formation of smaller granulomas. Granulomas in Irf5-/- mice are characterized by an increased IL-4 and IL-10 response and concomitant low iNOS expression. Collectively, these results identify IRF-5 as a critical molecular switch for the development of Th1 immune responses following L. donovani infections and reveal an indirect role of IRF-5 in the regulation of iNOS expression

Regulation of immunity during visceral Leishmania infection

Unicellular eukaryotes of the genus Leishmania are collectively responsible for a heterogeneous group of diseases known as leishmaniasis. The visceral form of leishmaniasis, caused by L. donovani or L. infantum, is a devastating condition, claiming 20,000 to 40,000 lives annually, with particular incidence in some of the poorest regions of the world. Immunity to Leishmania depends on the development of protective type I immune responses capable of activating infected phagocytes to kill intracellular amastigotes. However, despite the induction of protective responses, disease progresses due to a multitude of factors that impede an optimal response. These include the action of suppressive cytokines, exhaustion of specific T cells, loss of lymphoid tissue architecture and a defective humoral response. We will review how these responses are orchestrated during the course of infection, including both early and chronic stages, focusing on the spleen and the liver, which are the main target organs of visceral Leishmania in the host. A comprehensive understanding of the immune events that occur during visceral Leishmania infection is crucial for the implementation of immunotherapeutic approaches that complement the current anti-Leishmania chemotherapy and the development of effective vaccines to prevent disease.The research leading to these results has received funding from the European Community’s Seventh Framework Programme under grant agreement No.602773 (Project KINDRED). VR is supported by a post-doctoral fellowship granted by the KINDReD consortium. RS thanks the Foundation for Science and Technology (FCT) for an Investigator Grant (IF/00021/2014). This work was supported by grants to JE from ANR (LEISH-APO, France), Partenariat Hubert Curien (PHC) (program Volubilis, MA/11/262). JE acknowledges the support of the Canada Research Chair Program

Comparative evaluation of possible ocular photochemical toxicity of fluoroquinolones meant for ocular use in experimental models

387-391Fluoroquinolones (FQs) are extensively used in bacterial keratitis and other intraocular infections. Since eye is constantly exposed to light, incidence of ocular phototoxicity due to commonly used FQs is of great interest for their safe use. Phototoxicity of commonly used FQs (ciprofloxacin, lomefloxacin, pefloxacin, ofloxacin, sparfloxacin and gatifloxacin), has been evaluated by using HET-CAM-UV model (Photo Hen Egg Test-C Chorioallantoic Membrane model). This study was further extended by adding lomefloxacin dissolved in bovine vitreous (0.5ml) on the chorioallantoic membrane (CAM). Using a standard scale, the phototoxic damage was assessed at different time intervals. Respective controls were kept in dark to distinguish the toxicity of the drugs per se. The results showed that the phototoxicity induced by lomefloxacin was very high followed by gatifloxacin and sparfloxacin and least for other drugs studied. Interestingly, lomefloxacin along with vitreous showed significantly low phototoxicity. This could be due to the antioxidant property of ascorbic acid present in the vitreous

Damage Assessment of A356 Al Alloy Under Ratcheting–Creep Interaction

The aim of this report was to examine the influence of asymmetric cyclic stress on the ratcheting behavior of A356 Al alloy with special emphasis on its postratcheting creep behavior. A series of A356 alloy specimens were deformed under asymmetrical cyclic loading with different combinations of mean stress and stress amplitude. These tests were carried out up to 2000 cycles. Followed by ratcheting, the specimens were subjected to impression creep tests under varied stresses and temperatures. It is revealed from the ratcheting tests that strain accumulation increases with increasing stress amplitude or mean stress. However, total accumulated ratcheting strain of the investigated alloy was significantly low compared to that reported for some other aluminum alloys. The results of creep tests indicated that predominantly dislocation climb–assisted creep occurred for the alloy. Postratcheted specimens exhibited higher creep rates compared to that of the as-received A356 alloy; this fact was attributed to the work softening of the specimens during the impression creep test. The extent of work softening was minimum in the specimen that accumulated the highest strain during ratcheting, leading to its lowest creep rate