265 research outputs found

    XRD, AFM and UV-Vis optical studies of PbSe thin films produced by chemical bath deposition method.

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    PbSe thin �films have been deposited on microscope glass substrates by chemical bath deposition technique. The chemical bath consisted of lead nitrate, sodium selenate and triethanolamine solutions. The influence of bath temperature on the properties of PbSe �lms was investigated. The X-ray diff�raction, atomic force microscope and UV/Vis Spectrophotometer were used to obtain the structural characterization, surface morphological and absorbance data, respectively. Based on the X-ray diff�raction results, the thin �films obtained were found to be polycrystalline in nature with cubic structure. The intensity of the (111) peak showed a signifi�cant increased as the bath temperature was increased from 40 to 80C. The �films deposited at 80C indicated that the crystallinity was improved and more PbSe peaks were observed. On the other hand, the grain size, fi�lm thickness and surface roughness were increased while band gap energy decreased as could be observed in atomic force microscope and UV-Vis optical studies, respectively

    Selfie addiction: the prodigious self-portraits

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    Background: Selfie’s are self-portrait taken to admire the excessive pride in one’s own appearance. When these selfies are taken persistently in increased numbers with futile efforts to stop taking them is called as “SELFIE ADDICTION”. There is an uncontrollable craving for taking selfie’s which has a great impact on the life style modifications substantially in the adolescent age group. This problem has just commenced but it has disseminated rapidly to a greater magnitude.Methods: This study was done as a community based cross sectional study at Pondicherry, Chennai and Kadaloor district during November 2015 and February 2016 with the objectives of assessing the prevalence and its risk factors of the Selfie addiction among adolescents. Individuals of adolescent age group were randomly selected and the data were collected using direct questionnaire method with proper informed consent. The data was entered in MS excel sheet and analysis was done using SPSS software.Results: A total of 766 college students were interviewed of which 53% were males with the mean age of 19 years. The purposes of taking selfies were time pass (46%), to admire themselves (14.5%), to post in social network sites (23.7%). Among the study participants 87% of them had the habit of taking selfies regularly using mobile phones and the number of selfies per minute varied from 2 to 10 per minute. The prevalence of selfie addiction was present among 111 (14.5%) and it was significantly associated with gender, higher version mobile phone users, early morning selfie takers, chronic mobile users.Conclusions: The prevalence of selfie addiction among adolescent population in our study was moderately high and hence interventions should be made to create cognizance among the general population about the risk factors and its consequences

    A study on serum lipid and malondialdehyde levels among diabetic patients

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    Background: Elevated levels of lipid peroxide in diabetes mellitus may be due to the alteration of function of erythrocytes membrane. This inhibits the activity of superoxide dismutase enzyme leading to accumulation of superoxide radicals which cause the maximum lipid peroxidation and tissue damage in diabetes. The objectives was to study was done with the objectives of assessing the serum lipid and malondialdehyde levels among diabetic population and matched control group.Methods: This study was done among 50 NIDDM, 50 IDDM and 50 controls at Thanjavur Medical College, Tamil Nadu, India for a period of one year at the Department of Diabetology after getting the informed consent and IEC clearance. This study included all ambulatory NIDDM and IDDM patients without any complications. The following investigations like serum malondialdehyde, blood sugar, HBA1C, serum lipid profile, blood urea, serum creatinine, urine albumin and sugar were done by standardized procedures and reagents after getting the detailed history and examination.Results: Among NIDDM group 78% were between 6.4 to 8 categories whereas in IDDM group only 28% were in this 6.4 to 8 category (HBA1C). Comparison of serum MDA values among three groups were done by ANOVA with two groups separately and it was highly significant. Multiple comparison of mean difference of MDA and lipid values among all the three groups showed statistically significant results with p value at 0.05.Conclusions: Lipid profile is increased in poor glycemic controlled patients (both IDDM and NIDDM patients) and it is reflected in high serum malondialdehyde levels

    Nuclear pumping of a neutral carbon laser

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    Nuclear pumped lasing on the neutral carbon line at 1.45 micron was achieved in mixtures of He-CO, He-N2-CO, He-CO2, and Ne-CO and Ne-CO2. A minimum thermal neutron flux of 2 x 10 to the 14th power sq cm-sec was sufficient for oscillation in the helium mixtures. The peak of the laser output was delayed up to 5.5 ms relative to the neutron pulse in He-CO2, He-N2-CO, Ne-CO, and Ne-CO2 mixtures while no delay was observed in He-CO mixtures. Lasing was obtained with helium pressures from 20 to 800 T, Ne pressures from 100 to 200 T, CO from 0.25 to 20 mT, N2 from 0.5 mT, and CO2 from 0.1 to 25 mT in the respective mixtures

    Genetic algorithm based adaptive offloading for improving IoT device communication efficiency

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    Improving the communication of Internet of Things (IoT) network is a challenging task as it connects a wide-range of heterogeneous mobile devices. With an extended support from cloud network, the mobile IoT devices demand flexibility and scalability in communication. Increase in density of communicating devices and user request, traffic handling and delay-less service are unenviable. This manuscript introduces genetic algorithm based adaptive offloading (GA-OA) for effective traffic handling in IoT-infrastructure-cloud environment. The process of offloading is designed to mitigate unnecessary delays in request process and to improve the success rate of the IoT requests. The fitness process of GA is distributed among the gateways and infrastructure to handle requests satisfying different communication metrics. The process of GA balances between the optimal and sub-optimal solutions generated to improve the rate of request response. Experimental results prove the consistency of the proposed GA-OA by improving request success ratio, achieving lesser complexity, delay and processing time

    Laser-Induced Cavitation for Controlling Crystallization from Solution

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    We demonstrate that a cavitation bubble initiated by a Nd:YAG laser pulse below breakdown threshold induces crystallization from supersaturated aqueous solutions with supersaturation and laser-energy dependent nucleation kinetics. Combining high-speed video microscopy and simulations, we argue that a competition between the dissipation of absorbed laser energy as latent and sensible heat dictates the solvent evaporation rate and creates a momentary supersaturation peak at the vapor-liquid interface. The number and morphology of crystals correlate to the characteristics of the simulated supersaturation peak

    Spontaneous low frequency BOLD signal variations from resting-state fMRI are decreased in Alzheimer disease

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    Previous studies have demonstrated altered brain activity in Alzheimer\u27s disease using task based functional MRI (fMRI), network based resting-state fMRI, and glucose metabolism from 18 F fluorodeoxyglucose-PET (FDG-PET). Our goal was to define a novel indicator of neuronal activity based on a first-order textural feature of the resting state functional MRI (RS-fMRI) signal. Furthermore, we examined the association between this neuronal activity metric and glucose metabolism from F-18 FDG-PET. We studied 15 normal elderly controls (NEC) and 15 probable Alzheimer disease (AD) subjects from the AD Neuroimaging Initiative. An independent component analysis was applied to the RS-fMRI, followed by template matching to identify neuronal components (NC). A regional brain activity measurement was constructed based on the variation of the RS-fMRI signal of these NC. The standardized glucose uptake values of several brain regions relative to the cerebellum (SUVR) were measured from partial volume corrected FDG-PET images. Comparing the AD and NEC groups, the mean brain activity metric was significantly lower in the accumbens, while the glucose SUVR was significantly lower in the amygdala and hippocampus. The RS-fMRI brain activity metric was positively correlated with cognitive measures and amyloid beta 1-42 cerebral spinal fluid levels; however, these did not remain significant following Bonferroni correction. There was a significant linear correlation between the brain activity metric and the glucose SUVR measurements. This proof of concept study demonstrates that this novel and easy to implement RS-fMRI brain activity metric can differentiate a group of healthy elderly controls from a group of people with AD

    Low-cost fluorescence microscope with microfluidic device fabrication for optofluidic applications

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    Optofluidic devices have revolutionized the manipulation and transportation of fluid at smaller length scales ranging from micrometers to millimeters. We describe a dedicated optical setup for studying laser-induced cavitation inside a microchannel. In a typical experiment, we use a tightly focused laser beam to locally evaporate the solution laced with a dye resulting in the formation of a microbubble. The evolving bubble interface is tracked using high-speed microscopy and digital image analysis. Furthermore, we extend this system to analyze fluid flow through fluorescence-Particle Image Velocimetry (PIV) technique with minimal adaptations. In addition, we demonstrate the protocols for the in-house fabrication of a microchannel tailored to function as a sample holder in this optical setup. In essence, we present a complete guide for constructing a fluorescence microscope from scratch using standard optical components with flexibility in the design and at a lower cost compared to its commercial analogues.Comment: N. Nagalingam and A. Raghunathan contributed equally to this wor

    Medial Prefrontal and Anterior Insular Connectivity in Early Schizophrenia and Major Depressive Disorder: A Resting Functional MRI Evaluation of Large-Scale Brain Network Models

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    Anomalies in the medial prefrontal cortex, anterior insulae, and large-scale brain networks associated with them have been proposed to underlie the pathophysiology of schizophrenia and major depressive disorder (MDD). In this study, we examined the connectivity of the medial prefrontal cortices and anterior insulae in 24 healthy controls, 24 patients with schizophrenia, and 24 patients with MDD early in illness with seed based resting state functional magnetic resonance imaging analysis using Statistical Probability Mapping. As hypothesized, reduced connectivity was found between the medial prefrontal cortex and the dorsal anterior cingulate cortex and other nodes associated with directed effort in patients with schizophrenia compared to controls while patients with MDD had reduced connectivity between the medial prefrontal cortex and ventral prefrontal emotional encoding regions compared to controls. Reduced connectivity was found between the anterior insulae and the medial prefrontal cortex in schizophrenia compared to controls, but contrary to some models emotion processing regions failed to demonstrate increased connectivity with the medial prefrontal cortex in MDD compared to controls. Although, not statistically significant after correction for multiple comparisons, patients with schizophrenia tended to demonstrate decreased connectivity between basal ganglia-thalamocortical regions and the medial prefrontal cortex compared to patients with MDD, which might be expected as these regions effect action. Results were interpreted to support anomalies in nodes associated with directed effort in schizophrenia and nodes associated with emotional encoding network in MDD compared to healthy controls
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