13 research outputs found
Physical property characterization of single step synthesized NdFeAsO0.80F0.20 bulk 50K superconductor
We report an easy single step synthesis route of title compound
NdFeAsO0.80F0.20 superconductor having bulk superconductivity below 50 K. The
title compound is synthesized via solid-state reaction route by encapsulation
in an evacuated (10-3 Torr) quartz tube. Rietveld analysis of powder X-ray
diffraction data shows that compound crystallized in tetragonal structure with
space group P4/nmm. R(T)H measurements showed superconductivity with Tc (R=0)
at 48 K and a very high upper critical field (Hc2) of up to 345 Tesla. Magnetic
measurements exhibited bulk superconductivity in terms of diamagnetic onset
below 50 K. The lower critical field (Hc1) is around 1000 Oe at 5 K. In normal
state i.e., above 60 K, the compound exhibited purely paramagnetic behavior and
thus ruling out the presence of any ordered FeOx impurity in the matrix. In
specific heat measurements a jump is observed in the vicinity of
superconducting transition (Tc) along with an upturn at below T=4 K due to the
AFM ordering of Nd+3 ions in the system. The Thermo-electric power (TEP) is
negative down to Tc, thus indicating dominant carriers to be of n-type in
NdFeAsO0.80F0.20 superconductor. The granularity of the bulk superconducting
NdFeAsO0.8F0.2 sample is investigated and the intra and inter grain
contributions have been individuated by looking at various amplitude and
frequencies of the applied AC drive magnetic field.Comment: 26pages text + Figures: comments/suggestions welcome
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Therapeutic potentials of Nigella sativa preparations and its constituents in the management of diabetes and its complications in experimental animals and patients with diabetes mellitus: A systematic review
Objective: The purpose of this up-to-date comprehensive systematic review was to evaluate and summarize all research studies in the field in order to clarify the magnitude of Nigella sativa (N. sativa) effects on the management of Diabetes mellitus (DM) and its complications. Methods: A systematic review was conducted in a Cochrane style and in accordance PRISMA checklist using the published studies in PubMed/MEDLINE, SCOPUS, and EMBASE databases that were searched up to January 2019. Abstracts that met PICO criteria for qualitative studies underwent dual review for data extraction to evaluate study quality and details. Results: Dietary supplementation with N. sativa preparations can improve various secondary complications of diabetic patients. N. sativa preparations possess antidiabetic, hypoglycemic, anti-hyperlipidemic, antihypertensive, and anti-obesity effects. Beneficial effects of N. sativa preparations include the restoration of the antioxidant defense systems, the increase in the activity of antioxidant enzymes, the decrease of inflammatory biomarkers, the suppression of the production pro-inflammatory mediators, improvement of endothelial dysfunction, and hepatic, kidney, heart and immune system functions. They have key roles in managing diabetes-induced inflammation and oxidative stress in diabetic patients. Conclusion: N. sativa preparations have key roles in herbal medicine as an adjuvant in the treatment and management of patients with DM and its complications. Moreover, the beneficial effects of N. sativa preparations were differently based on dosage forms, active ingredients, and duration of intervention. The best dosage to improve glycemic indices and lipid and lipoprotein profiles is 2 g daily powdered N. sativa for at least 12 weeks. © 2020 Elsevier Lt