349 research outputs found

    Penetration of buoyancy driven current due to a wind forced river plume

    Get PDF
    The long term response of a plume associated with freshwater penetration into ambient, ocean water under upwelling favorable winds is studied using the Regional Ocean Modeling System (ROMS) in an idealized domain. Three different cases were examined, including a shore perpendicular source and shore parallel source with steady winds, and a shore perpendicular source with oscillating alongshore winds. Freshwater flux is used to define plume penetration. Alongshore penetration of buoyant currents is proportional to freshwater input and inversely proportional to upwelling wind stress strength. Strong wind more quickly prevents fresh water’s penetration. Under upwelling favorable winds, the plume is advected offshore by Ekman transport as well as upcoast by the mean flow. This causes the bulge to detach from the coast and move to upcoast and offshore with a 45 degree angle. The path of the bulge is roughly linear, and is independent of wind strength. The bulge speed has a linear relationship with the wind stress strength, and it matches the expected speed based on Ekman theory. Sinusoidal wind leads to sequential upwelling and downwelling events. The plume has an asymmetric response to upwelling and downwelling and fresh water flux is changed immediately by wind. During downwelling, the downcoast fresh water transport is greatest, while it is reduced during upwelling. Background mean flow in the downcoast direction substantially increases alongshore freshwater transport

    Brief Review of the Role of Glycogen Synthase Kinase-3β in Amyotrophic Lateral Sclerosis

    Get PDF
    Glycogen synthase kinase-3β (GSK-3β) is known to affect a diverse range of biological functions controlling gene expression, cellular architecture, and apoptosis. GSK-3β has recently been identified as one of the important pathogenic mechanisms in motor neuronal death related to amyotrophic lateral sclerosis (ALS). Therefore, the development of methods to control GSK-3β could be helpful in postponing the symptom progression of ALS. Here we discuss the known roles of GSK-3β in motor neuronal cell death in ALS and the possibility of employing GSK-3β modulators as a new therapeutic strategy

    Dependence of Performance of Si Nanowire Solar Cells on Geometry of the Nanowires

    Get PDF
    The dependence of performance of silicon nanowires (SiNWs) solar cells on the growth condition of the SiNWs has been described. Metal-assisted electroless etching (MAE) technique has been used to grow SiNWs array. Different concentration of aqueous solution containing AgNO3 and HF for Ag deposition is used. The diameter and density of SiNWs are found to be dependent on concentration of solution used for Ag deposition. The diameter and density of SiNWs have been used to calculate the filling ratio of the SINWs arrays. The filling ratio is increased with increase in AgNO3 concentration, whereas it is decreased with increase in HF concentration. The minimum reflectance value achieved is ~1% for SiNWs of length of ~1.2 μm in the wavelength range of 300–1000 nm. The performance and diode parameters strongly depend on the geometry of SiNWs. The maximum short circuit current density achieved is 35.6 mA/cm2. The conversion efficiency of solar cell is 9.73% for SiNWs with length, diameter, and wire density of ~1.2 μm, ~75 nm, and 90 μm−2, respectively

    Fabrication and characterization of silicon wire solar cells having ZnO nanorod antireflection coating on Al-doped ZnO seed layer

    Get PDF
    In this study, we have fabricated and characterized the silicon [Si] wire solar cells with conformal ZnO nanorod antireflection coating [ARC] grown on a Al-doped ZnO [AZO] seed layer. Vertically aligned Si wire arrays were fabricated by electrochemical etching and, the pn junction was prepared by spin-on dopant diffusion method. Hydrothermal growth of the ZnO nanorods was followed by AZO film deposition on high aspect ratio Si microwire arrays by atomic layer deposition [ALD]. The introduction of an ALD-deposited AZO film on Si wire arrays not only helps to create the ZnO nanorod arrays, but also has a strong impact on the reduction of surface recombination. The reflectance spectra show that ZnO nanorods were used as an efficient ARC to enhance light absorption by multiple scattering. Also, from the current-voltage results, we found that the combination of the AZO film and ZnO nanorods on Si wire solar cells leads to an increased power conversion efficiency by more than 27% compared to the cells without it. © 2012 Baek et al.1

    Antidiabetic Activities of Abutilon indicum (L.) Sweet Are Mediated by Enhancement of Adipocyte Differentiation and Activation of the GLUT1 Promoter

    Get PDF
    Abutilon indicum (L.) Sweet is an Asian phytomedicine traditionally used to treat several disorders, including diabetes mellitus. However, molecular mechanisms supporting the antidiabetic effect of A. indicum L. remain unknown. The aim of this study was to evaluate whether extract of A. indicum L. improves insulin sensitivity. First, we observed the antidiabetic activity of aqueous extract of the entire plant (leaves, twigs and roots) of A. indicum L. on postprandial plasma glucose in diabetic rats. The subsequent experiments revealed that butanol fractions of the extract bind to PPARγ and activate 3T3-L1 differentiation. To measure glucose uptake enhanced by insulin-like activity, we used rat diaphragm incubated with various concentrations of the crude extract and found that the extract enhances glucose consumption in the incubated solution. Our data also indicate that the crude extract and the fractions (water and butanol) did not affect the activity of kinases involved in Akt and GSK-3β pathways; however, the reporter assay showed that the crude extract could activate glucose transporter 1 (GLUT1) promoter activity. These results suggest that the extract from A. indicum L. may be beneficial for reducing insulin resistance through its potency in regulating adipocyte differentiation through PPARγ agonist activity, and increasing glucose utilization via GLUT1

    Visible emission from Ce-doped ZnO nanorods grown by hydrothermal method without a post thermal annealing process

    Get PDF
    Visible light-emitting Ce-doped ZnO nanorods [NRs] without a post thermal annealing process were grown by hydrothermal method on a Si (100) substrate at a low temperature of 90°C. The structural investigations of Ce-doped ZnO NRs showed that the Ce3+ ions were successfully incorporated into the ZnO lattice sites without forming unwanted Ce-related compounds or precipitates. The optical investigation by photoluminescence spectra shows that the doped Ce3+ ions in the ZnO NRs act as an efficient luminescence center at 540 nm which corresponds to the optical transition of 5d → 4f orbitals in the Ce3+ ions. The photoluminescence intensity of the Ce-doped ZnO NRs increased with the increasing content of the Ce-doping agent because the energy transfer of the excited electrons in ZnO to the Ce3+ ions would be enhanced by increased Ce3+ ions

    Enhancement of phase separation in the InGaN layer for self-assembled In-rich quantum dots

    Get PDF
    The enhancement of phase separation in the InGaN layer grown on a GaN layer with a rough surface was investigated for the formation of self-assembled In-rich quantum dots(QDs) in the InGaN layer. Transmission electron microscopy images showed that In-rich QDs with a size of 2–5 nm were formed even in an InGaN layer with a low indium content, and a layer thickness less than the critical thickness. The room-temperature photoluminescence(PL) spectrum of this layer showed emission peaks corresponding to In-rich QDs. The temperature-dependent PL spectra showed dominant peak shifts to the lower energy side, indicating that the self-assembled In-rich QDs are formed in the InGaN layer grown on a rough GaNsurface and that the carriers are localized in In-rich QDs

    Duodenal Mucosa-Associated Lymphoid Tissue Lymphoma: A Case Report

    Get PDF
    Primary duodenal mucosa associated lymphoid tissue (MALT) lymphoma is very rare, and little is known about its clinical course or effective treatment. We describe a case of primary duodenal MALT lymphoma that was resistant to Helicobacter pylori (H. pylori) eradication and regressed after chemotherapy with cyclophosphamide, vincristine, and prednisolone (CVP). A 71-year-old woman was referred to our department because of epigastric pain and dyspepsia. Gastroduodenoscopy revealed an irregular mucosal nodular lesion with ulceration extending from the bulb to the second portion of the duodenum. Histopathological examination of a biopsy specimen disclosed low-grade MALT lymphoma composed of atypical lymphoid cells with lymphoepithelial lesion. Abdominal CT scans revealed 0.5 to 1.5 cm lymph nodes in the peritoneal cavity, suggestive of lymph node metastasis. We successfully eradicated H. pylori but did not see signs of remission. We administered systemic CVP chemotherapy every 3 weeks. After 6 courses of CVP, the patient achieved complete remission and was followed up without recurrence for about a year

    A New Onset of Systemic Lupus Erythematosus Developed After Bee Venom Therapy

    Get PDF
    Lupus is a systemic autoimmune disease of an unknown origin, and systemic lupus erythematosus (SLE) can be triggered by numerous stimuli. Bee venom therapy is an alternative therapy that is believed to be effective for various kinds of arthritis. We present here a case of a 49-year-old female who experienced a new onset lupus after undergoing bee venom therapy, and this looked like a case of angioedema. The patient was successfully treated with high dose steroids and antimalarial drugs. We discuss the possibility of bee venom contributing to the development of SLE, and we suggest that such treatment should be avoided in patients with lupus

    The reemergence of long-term potentiation in aged Alzheimer's disease mouse model

    Get PDF
    Mouse models of Alzheimer’s disease (AD) have been developed to study the pathophysiology of amyloid β protein (Aβ) toxicity, which is thought to cause severe clinical symptoms such as memory impairment in AD patients. However, inconsistencies exist between studies using these animal models, specifically in terms of the effects on synaptic plasticity, a major cellular model of learning and memory. Whereas some studies find impairments in plasticity in these models, others do not. We show that long-term potentiation (LTP), in the CA1 region of hippocampal slices from this mouse, is impared at Tg2576 adult 6–7 months old. However, LTP is inducible again in slices taken from Tg2576 aged 14–19 months old. In the aged Tg2576, we found that the percentage of parvalbumin (PV)-expressing interneurons in hippocampal CA1-3 region is significantly decreased, and LTP inhibition or reversal mediated by NRG1/ErbB signaling, which requires ErbB4 receptors in PV interneurons, is impaired. Inhibition of ErbB receptor kinase in adult Tg2576 restores LTP but impairs depotentiation as shown in aged Tg2576. Our study suggests that hippocampal LTP reemerges in aged Tg2576. However, this reemerged LTP is an insuppressible form due to impaired NRG1/ErbB signaling, possibly through the loss of PV interneurons
    corecore