107 research outputs found

    Effects of ethanolic and aqueous leaf extracts of Bryophyllum pinnatum on haematological parameters of normal and streptozotocin–induced diabetic rats

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    The effect of the oral administration of both ethanolic and aqueous leaf extracts from Bryophyllum pinnatum (BP) on haematological parameters of normal and streptozotocin - induced (STZ) diabetic rat was investigated. Twenty-five male Wister rats were used and divided into five groups of five rats each. They were designated as (Normal Control – NC, Diabetic Control – DC, Diabetic Ethanolic Extract – DEE, Diabetic Aqueous Extract – DAE, and Normal Aqueous Extract – NAE). Groups NC and DC served as ‘control’ animals receiving food and water only. Groups DC, DEE and DAE were injected intraperitoneally with 65mg/kg body weight streptozotocin. Induction of diabetes mellitus was confirmed after 48 hours using glucose test strips. The test rats were all treated with 100mg/kgbwt ethanolic and aqueous leaf extracts of Bryophyllum pinnatum for 28days. At the end of the 28days, the rats were sacrificed and whole blood collected for Haematological assay. Results obtained showed a significant difference(P<0.05) in White Blood Cell (WBC), Red Blood Cell (RBC), Platelet (PLT), Haemoglobin (HBG), Packed Cell Volume (PCV), Mean Cell Volume (MCV), Mean Cell Haemoglobin (MCH), Mean Cell Haemoglobin Concentration (MCHC) and Lymphocytes (LYM) in treated rats with BP leaf extracts when compared to the diabetic and normal control groups

    Electronic Structures and Bonding of Oxygen on Plutonium Layers

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    Oxygen adsorption on delta-Pu (100) and (111) surfaces have been studied at both non-spin-polarized and spin-polarized levels using the generalized gradient approximation of density functional theory (GGA-DFT)with Perdew and Wang functionals. The center position of the (100) surface is found to be the most favorable site with chemisorption energies of 7.386 eV and 7.080 eV at the two levels of theory. The distances of the oxygen adatom from the Pu surface are found to be 0.92A and 1.02A, respectively. For the (111) surface non-spin-polarized calculations, the center position is also the preferred site with a chemisorption energy of 7.070 eV and the distance of the adatom being 1.31A, but for spin-polarized calculations the bridge and the center sites are found to be basically degenerate, the difference in chemisorption energies being only 0.021 eV. In general, due to the adsorption of oxygen, plutonium 5f orbitals are pushed further below the Fermi energy, compared to the bare plutonium layers. The work function, in general, increases due to oxygen adsorption on plutonium surfaces.Comment: Spin-polarization is considered, and the paper is revised accordingl

    Porphyrin-modified antimicrobial peptide indicators for detection of bacteria

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    This study demonstrates the potential of porphyrin modified antimicrobial peptides for indication of bacterial targets on the basis of changes in the spectrophotometric characteristics of the construct. Detection is a result of changes in the structure of the antimicrobial peptide upon target binding. Those constructs comprised of peptides that offer little or no change in conformation upon interaction with bacterial cells demonstrated negligible changes in absorbance and fluorescence when challenged using Escherichia coli or Bacillus cereus. CD analysis confirms the presence/absence of conformational changes in the porphyrin-peptide constructs. Differing spectrophotometric responses were observed for constructs utilizing different peptides. The incorporation of metals into the porphyrin component of the constructs was shown to alter their spectrophotometric characteristics as well as the resulting absorbance and fluorescence changes noted upon interaction with a target. The described constructs offer the potential to enable a new type of biosensing approach in which the porphyrin-peptide indicators offer both target recognition and optical transduction, requiring no additional reagents

    A two-fluid model for high-viscosity upward annular flow in vertical pipes

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    Proper selection and application of interfacial friction factor correlations has a significant impact on prediction of key flow characteristics in gas–liquid two-phase flows. In this study, experimental investigation of gas–liquid flow in a vertical pipeline with internal diameter of 0.060 m is presented. Air and oil (with viscosities ranging from 100–200 mPa s) were used as gas and liquid phases, respectively. Superficial velocities of air ranging from 22.37 to 59.06 m/s and oil ranging from 0.05 to 0.16 m/s were used as a test matrix during the experimental campaign. The influence of estimates obtained from nine interfacial friction factor models on the accuracy of predicting pressure gradient, film thickness and gas void fraction was investigated by utilising a two-fluid model. Results obtained indicate that at liquid viscosity of 100 mPa s, the interfacial friction factor correlation proposed by Belt et al. (2009) performed best for pressure gradient prediction while the Moeck (1970) correlation provided the best prediction of pressure gradient at the liquid viscosity of 200 mPa s. In general, these results indicate that the two-fluid model can accurately predict the flow characteristics for liquid viscosities used in this study when appropriate interfacial friction factor correlations are implemented

    Experimental Study on Sand Transport Characteristics in Horizontal and Inclined Two-Phase Solid-Liquid Pipe Flow

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    An experimental investigation on the hydraulic transport of sand particles in pipelines is presented in both horizontal and 30° upward inclined orientations. The pipe, with an internal diameter of 0.0254 m, had sand transported in various water superficial velocities at low and high sand concentrations [0.1%–10% volume-to-volume ratio (v/v)]. Sand particles were polydisperse (144–250 μm) with

    Stress among UK academics : identifying who copes best?

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    This paper examined the levels of stress and coping strategies among UK academics. Adopting a positive psychology approach, the influence of the character strengths of hope, optimism, gratitude and self-efficacy, on stress, subjective well-being (SWB), and mental health (GHQ) was examined in 216 academics in a UK university. The study explored the relationship between coping styles and work-coping variables of sense of coherence and work locus of control and stress. No significant differences on the stress, well-being and mental health measures were found for participants' gender, whether in full-time or part-time employment and level of seniority within the university. Participants using problem-focussed coping experienced lower levels of stress while dysfunctional coping was a positive predictor of stress. Hope agency, hope pathway, gratitude, optimism and self-efficacy were the strongest positive predictors of satisfaction with life (SWL), while levels of perceived stress negatively predicted SWL. Gratitude, hope agency and self-efficacy positively predicted positive affect, while stress was a negative predictor. Gratitude, hope agency, self-efficacy and optimism were negative significant predictors of negative affect while stress was a positive predictor. Gratitude positively predicted mental health, while stress was a negative predictor and optimism was a significant moderator of the relationship between stress and mental health. Academics with higher levels of gratitude, self-efficacy, hope and optimism report lower levels of stress at work and higher levels of well-being as measured by higher life satisfaction, higher positive affect and lower negative affect. New approaches to stress management training are suggested based on these findings

    A density functional study of molecular oxygen adsorption and reaction barrier on Pu (100) surface

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    Oxygen molecule adsorptions on a Pu (100) surface have been studied in detail, using the generalized gradient approximation to density functional theory. Dissociative adsorption with a layer by layer alternate spin arrangement of the plutonium layer is found to be energetically more favorable compared to molecular adsorption. Hor2 approach on a bridge site without spin polarization was found to the highest chemisorbed site with energy of 8.787 eV among all the cases studied. The second highest chemisorption energy of 8.236 eV, is the spin-polarized Hor2 or Ver approach at center site. Inclusion of spin polarization affects the chemisorption processes significantly, non-spin-polarized chemisorption energies being typically higher than the spin-polarized energies. We also find that the 5f electrons to be more localized in spin-polarized cases compared to the non-spin-polarized counterparts. The ionic part of O-Pu bonding plays a significant role, while the Pu 5f-O 2p hybridization was found to be rather week. Also, adsorptions of oxygen push the top of 5f band deeper away from the Fermi level, indicating further bonding by the 5f orbitals might be less probable. Except for the interstitial sites, the work functions increase due to adsorptions of oxygen

    Semiempirical calculation of van der Waals coefficients for alkali-metal and alkaline-earth-metal atoms

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    The van der Waals coefficients, C-6, C-8, and C-10 for the alkali-metal (Li, Na, K, and Rb) and alkaline-earth-metal (Be, Mg, Ca, and Sr) atoms are estimated by a combination of ab initio and semiempirical methods. Polarizabilities and atom-wall coefficients are given as a diagnostic check, and the lowest order nonadiabatic dispersion coefficient, D-8 and the three-body coefficient, C-9 are also presented. The dispersion coefficients are in agreement with the available relativistic many-body perturbation theory calculations. The contribution from the core was included by using constrained sum rules involving the core polarizability and Hartree-Fock expectation values to estimate the f-value distribution

    Bone Marrow Transplantation Restores Follicular Maturation and Steroid Hormones Production in a Mouse Model for Primary Ovarian Failure

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    Recent studies suggest that bone marrow stem cells (BMSCs) are promising grafts to treat a variety of diseases, including reproductive dysfunction. Primary ovarian failure is characterized by amenorrhea and infertility in a normal karyotype female, with an elevated serum level of follicle-stimulating hormone (FSH) and a decrease level of estrogen caused by a mutation in FSH receptor (FSHR) gene. Currently, there is no effective treatment for this condition. The phenotype of FSHR (−/−) mouse, FORKO (follitropin receptor knockout), is a suitable model to study ovarian failure in humans. Female FORKO mice have elevated FSH, decreased estrogen levels, are sterile because of the absence of folliculogenesis, and display thin uteri and small nonfunctional ovaries. In this study, we determined the effects of BMSC transplantation on reproductive physiology in this animal model. Twenty four hours post BMSC transplantation, treated animals showed detectable estroidogeneic changes in daily vaginal smear. Significant increase in total body weight and reproductive organs was observed in treated animals. Hemotoxylin and eosin (H&E) evaluation of the ovaries demonstrated significant increase in both the maturation and the total number of the follicles in treated animals. The FSH dropped to 40–50% and estrogen increased 4–5.5 times in the serum of treated animals compared to controls. The FSHR mRNA was detected in the ovaries of treated animals. Our results show that intravenously injected BMSCs were able to reach the ovaries of FORKO mice, differentiate and express FHSR gene, make FSHR responsive to FSH, resume estrogen hormone production, and restore folliculogenesis
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