246 research outputs found

    Scattering and Bound State Solutions of the Yukawa Potential within the Dirac Equation

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    In the presence of spin symmetry case, we obtain bound and scattering states solutions of the Dirac equation for the equal scalar and vector Yukawa potentials for any spin-orbit quantum number κ. The approximate analytical solutions are presented for the bound and scattering states and scattering phase shifts

    The effect of lovastatin on cognition impairment induced by bilateral electrical lesion of nucleus basalis magnocellularis in the Alzheimerâs disease model in adult male rats

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    Background: Statins, inhibitors of 3-hydroxy-3-methyl glutaryl coenzyme A reductase, are widely used as medication to lower cholesterol levels in human patients. Much evidence indicates that statins can also exert neuroprotective actions. So, this study aimed at examining the effect of lovastatin on cognition deficit induced by bilateral electrical lesion of nucleus basalis magnocellularis (NBM) in the Alzheimer’s disease model in adult male rats. Materials and Methods: In this experimental study, 56 adult male wistar rats were divided into 8 groups (n=7): control (intact), NBM lesion group (which received electrically- induced lesion 0.5 mA in 3s), sham group (the electrode was impaled into the NBM with no lesion(, lovastatin groups (lesion+1, 5, 10, 20 mg/kg) and DMSO 5 group (NBM lesion +DMSO 5). Acquisition and retention testing was done by using an eight-radial arm maze in which the patterns of arm entries were recorded for calculating working memory errors, reference memory error and latency in each group. Results: The bilateral NBM lesion resulted in significant reduction of spatial memory in acquisition and retention tests in the form of increased working and reference memory errors compared to the control group (P<0.05). Post-lesion treatment with lovastatin improved the parameters of spatial memory errors in the acquisition and retention tasks compared to the lesion group. Conclusion: The electrical NBM lesion can reduce spatial memory function and the lovastatin therapy after brain injury improved cognitive disorders. It seems that lovastatin by reducing the activity of the acetylcholinesterase enzyme and increasing acetylcholine transferase enzyme activity can cause improvement in learning and memory capability

    Influence du cadmium (Cd ++

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    Microfluidic systems for the analysis of the viscoelastic fluid flow phenomena in porous media

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    In this study, two microfluidic devices are proposed as simplified 1-D microfluidic analogues of a porous medium. The objectives are twofold: firstly to assess the usefulness of the microchannels to mimic the porous medium in a controlled and simplified manner, and secondly to obtain a better insight about the flow characteristics of viscoelastic fluids flowing through a packed bed. For these purposes, flow visualizations and pressure drop measurements are conducted with Newtonian and viscoelastic fluids. The 1-D microfluidic analogues of porous medium consisted of microchannels with a sequence of contractions/ expansions disposed in symmetric and asymmetric arrangements. The real porous medium is in reality, a complex combination of the two arrangements of particles simulated with the microchannels, which can be considered as limiting ideal configurations. The results show that both configurations are able to mimic well the pressure drop variation with flow rate for Newtonian fluids. However, due to the intrinsic differences in the deformation rate profiles associated with each microgeometry, the symmetric configuration is more suitable for studying the flow of viscoelastic fluids at low De values, while the asymmetric configuration provides better results at high De values. In this way, both microgeometries seem to be complementary and could be interesting tools to obtain a better insight about the flow of viscoelastic fluids through a porous medium. Such model systems could be very interesting to use in polymer-flood processes for enhanced oil recovery, for instance, as a tool for selecting the most suitable viscoelastic fluid to be used in a specific formation. The selection of the fluid properties of a detergent for cleaning oil contaminated soil, sand, and in general, any porous material, is another possible application

    Evaluation of the effect of MbNPV on cabbage moth, Plutella xylostella (Lep.: Plutellidae), in laboratory conditions

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    Cabbage moth, Plutella xylostella L., is the most important pest in cabbage and canola cultures in Iran. Nuclear polyhedrosis viruses are known as important natural enemies of this pest. Because of economic importance of cabbage moth and the necessity of its control, MbNPV (Baculoviridae) was chosen to evaluate its effect on cabbage moth. Experimental data showed that the virus had high virulence and could be considered as the important agent for the control of this insect. In infestation of egg surfaces with 1 Ã 105 PIB/ml of MbNPV, all of larvae died three days after hatching. The LC50 value for the second instar larvae of cabbage moth was calculated 11.99 PIB/mm2. The LT50 values for the same larvae with 19.5 and 47.86 PIB/mm2 doses of MbNPV were 7.16 and 6.11 days, respectively. Mean percentages of mortality with 47.86 PIB/mm2 for 2nd, 3rd and 4th instar larvae were 74.44, 42.78 and 11.11, respectively

    Nucleobindin-1 regulates ECM degradation by promoting intra-Golgi trafficking of MMPs.

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    Matrix metalloproteinases (MMPs) degrade several ECM components and are crucial modulators of cell invasion and tissue organization. Although much has been reported about their function in remodeling ECM in health and disease, their trafficking across the Golgi apparatus remains poorly understood. Here we report that the cis-Golgi protein nucleobindin-1 (NUCB1) is critical for MMP2 and MT1-MMP trafficking along the Golgi apparatus. This process is Ca2+-dependent and is required for invasive MDA-MB-231 cell migration as well as for gelatin degradation in primary human macrophages. Our findings emphasize the importance of NUCB1 as an essential component of MMP transport and its overall impact on ECM remodeling. © 2020 Pacheco-Fernandez et al

    Comparison of Short-Term Estrogenicity Tests for Identification of Hormone-Disrupting Chemicals

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    The aim of this study was to compare results obtained by eight different short-term assays of estrogenlike actions of chemicals conducted in 10 different laboratories in five countries. Twenty chemicals were selected to represent direct-acting estrogens, compounds with estrogenic metabolites, estrogenic antagonists, and a known cytotoxic agent. Also included in the test panel were 17β-estradiol as a positive control and ethanol as solvent control. The test compounds were coded before distribution. Test methods included direct binding to the estrogen receptor (ER), proliferation of MCF-7 cells, transient reporter gene expression in MCF-7 cells, reporter gene expression in yeast strains stably transfected with the human ER and an estrogen-responsive reporter gene, and vitellogenin production in juvenile rainbow trout. 17β-Estradiol, 17α-ethynyl estradiol, and diethylstilbestrol induced a strong estrogenic response in all test systems. Colchicine caused cytotoxicity only. Bisphenol A induced an estrogenic response in all assays. The results obtained for the remaining test compounds—tamoxifen, ICI 182.780, testosterone, bisphenol A dimethacrylate, 4-n-octylphenol, 4-n-nonylphenol, nonylphenol dodecylethoxylate, butylbenzylphthalate, dibutylphthalate, methoxychlor, o,p′-DDT, p,p′-DDE, endosulfan, chlomequat chloride, and ethanol—varied among the assays. The results demonstrate that careful standardization is necessary to obtain a reasonable degree of reproducibility. Also, similar methods vary in their sensitivity to estrogenic compounds. Thus, short-term tests are useful for screening purposes, but the methods must be further validated by additional interlaboratory and interassay comparisons to document the reliability of the methods
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