Dependence of Exchange Bias on Interparticle Interactions in Co/CoO Core/Shell Nanostructures

This article reports the dependence of exchange bias (EB) effect on interparticle interactions in nanocrystalline Co/CoO core/shell structures, synthesized using the conventional sol-gel technique. Analysis via powder X-Ray diffraction (PXRD) studies and transmission electron microscope (TEM) images confirm the presence of crystalline phases of core/shell Co/CoO with average particle size ≈ 18 nm. Volume fraction (φ) is varied (from 20% to 1%) by the introduction of a stoichiometric amount of non-magnetic amorphous silica matrix (SiO2) which leads to a change in interparticle interaction (separation). The influence of exchange and dipolar interactions on the EB effect, caused by the variation in interparticle interaction (separation) is studied for a series of Co/CoO core/shell nanoparticle systems. Studies of thermal variation of magnetization (M−T) and magnetic hysteresis loops (M−H) for the series point towards strong dependence of magnetic properties on dipolar interaction in concentrated assemblies whereas individual nanoparticle response is dominant in isolated nanoparticle systems. The analysis of the EB effect reveals a monotonic increase of coercivity (HC) and EB field (HE) with increasing volume fraction. When the nanoparticles are close enough and the interparticle interaction is significant, collective behavior leads to an increase in the effective antiferromagnetic (AFM) CoO shell thickness which results in high HC and HE. Moreover, in concentrated assemblies, the dipolar field superposes to the local exchange field and enhances the EB effect contributing as an additional source of unidirectional anisotropy

Chemical, microbial and safety profiling of a standardized Withania somnifera (Ashwagandha) extract and Withaferin A, a potent novel phytotherapeutic of the millennium

Background:Withania somnifera (L.) Dunal, popularly known as Ashwagandha, is an ethnomedicinal plant with multiple pharmacotherapeutic applications. The diverse medicinal properties of the plant are largely due to the presence of withanolides, a group of C28 ergostane based steroidal lactones, with several sites of unsaturation and oxygenation. Withaferin A, a major with anolide present in Ashwagandha plant accounts for its emerging new roles to treat cancer, arthritis, inflammatory responses, immunomodulatory properties, and neuronal disorders. The root and leaf extracts are specifically important constituent materials for the development of phytotherapeutics, mostly intended for oral consumption. Several studies have been carried out to delineate the toxic manifestations of the extract for human consumption. Objective:Establish the broad-spectrum safety of W-ferinAmax ashwagandha (WFA). Study: This investigation demonstrated a novel, standardized W-ferinAmax ashwagandha (WFA) extraction technology from the whole herb of Withania sominfera, conducted HPLC analysis to identify the constituents, detected the heavy metals, microbiological contaminants, pesticides contaminants, and safety profile. Results:A novel extraction technology was employed to obtain WFA from the whole plant of Withania sominfera. HPLC analysis revealed that WFA contains a total of 15.4% Withanolides. In particular, Withaferin A, Withanoside IV, and Withanolide A contents were 6.469%, 1.022%, and 0.073%, respectively. The extract contained only 0.403 ppm of heavy metals out of which traces of arsenic, mercury and lead were detected, and cadmium was absent. USP recommended 80 residue basic pesticide screen indicated that the extraction was safe for human consumption. It was also found to be free from pathogenic microbes as assessed by the absence of E. coli and other coliforms, Salmonella and Staphylococcus species. Conclusion: The data generated cumulatively indicated that WFA is safe for further downstream processing to and for human consumption

Prevalence of ischemic heart disease among urban population of Siliguri, West Bengal

<b>Objectives:</b> To determine the prevalence of ischemic heart disease and the associated risk factors among the urban population of Siliguri. <b> Materials and Methods:</b> A cross-sectional survey of a random sample of the population aged &#8805;40 years old in the Municipal Corporation area of Siliguri. Study variables were age, sex, occupation, addiction, food habit, physical activity, body mass index, blood pressure, and electrocardiogram change. <b> Results:</b> Out of 250 individuals who took part in this study, 29 (11.6&#x0025;) had ischemic heart disease (IHD) and 118 (47.2&#x0025;) had hypertension. Males had a higher (13.5&#x0025;) prevalence of IHD than females (9.4&#x0025;). About 5&#x0025; of the patients had asymptomatic IHD. IHD among the study population is significantly associated with hypertension and smoking

Dependence of Exchange Bias on Interparticle Interactions in Co/CoO Core/Shell Nanostructures

This article reports the dependence of exchange bias (EB) effect on interparticle interactions in nanocrystalline Co/CoO core/shell structures, synthesized using the conventional sol-gel technique. Analysis via powder X-Ray diffraction (PXRD) studies and transmission electron microscope (TEM) images confirm the presence of crystalline phases of core/shell Co/CoO with average particle size &asymp; 18 nm. Volume fraction (&phi;) is varied (from 20% to 1%) by the introduction of a stoichiometric amount of non-magnetic amorphous silica matrix (SiO2) which leads to a change in interparticle interaction (separation). The influence of exchange and dipolar interactions on the EB effect, caused by the variation in interparticle interaction (separation) is studied for a series of Co/CoO core/shell nanoparticle systems. Studies of thermal variation of magnetization (M&minus;T) and magnetic hysteresis loops (M&minus;H) for the series point towards strong dependence of magnetic properties on dipolar interaction in concentrated assemblies whereas individual nanoparticle response is dominant in isolated nanoparticle systems. The analysis of the EB effect reveals a monotonic increase of coercivity (HC) and EB field (HE) with increasing volume fraction. When the nanoparticles are close enough and the interparticle interaction is significant, collective behavior leads to an increase in the effective antiferromagnetic (AFM) CoO shell thickness which results in high HC and HE. Moreover, in concentrated assemblies, the dipolar field superposes to the local exchange field and enhances the EB effect contributing as an additional source of unidirectional anisotropy

A randomized double blind placebo controlled trial to assess the safety and efficacy of a patented fenugreek (Trigonella foenum-graecum) seed extract in Type 2 diabetics

Background: Fenugreek plant (Trigonella foenum-graecum) constitutes a traditionally acclaimed herbal remedy for many human ailments including diabetes, obesity, neurodegenerative diseases, and reproductive disorders. It is also used as an effective anti-oxidative, anti-inflammatory, antibacterial, and anti-fungal agent. The seed of the plant is especially enriched in several bioactive molecules including polyphenols, saponins, alkaloids, and flavonoids and has demonstrated potential to act as an antidiabetic phytotherapeutic. A novel patented formulation (Fenfuro®) was developed in our laboratory from the fenugreek seeds which contained \u3e45% furostanolic saponins (HPLC). Objective: A placebo-controlled clinical compliance study was designed to assess the effects of complementing Fenfuro® on a randomized group of human volunteers on antidiabetic therapy (Metformin and sulphonylurea) in controlling the glycemic index along with simultaneous safety assessment. Study methodology and trial design: In a randomized double-blind, placebo-controlled trial, 42 individuals (21 male and 21 female volunteers) in the treatment group (out of 57 enrolled) and 39 individuals (17 male and 22 female volunteers) in the placebo group (out of 47 enrolled), all on antidiabetic therapy with Metformin/Metformin with sulphonyl urea within the age group of 18–65 years were administered either 1,000 mg (500 mg × 2) (Fenfuro®) capsules or placebo over a period of 12 consecutive weeks. Fasting and postprandial glucose along with glycated hemoglobin were determined as primary outcomes to assess the antidiabetic potential of the formulation. Moreover, in order to evaluate the safety of the formulation, C-peptide and Thyroid Stimulating Hormone (TSH) levels as well as immunohematological parameters were assessed between the treatment and placebo groups at the completion of the study. Results: After 12 weeks of administration, both fasting as well as postprandial serum glucose levels decreased by 38 and 44% respectively in the treatment group. Simultaneously, a significant reduction in glycated hemoglobin by about 34.7% was also noted. The formulation did not have any adverse effect on the study subjects as there was no significant change in C- peptide level and TSH level; liver, kidney, and cardiovascular function was also found to be normal as assessed by serum levels of key immunohematological parameters. No adverse events were reported. Conclusion: This clinical compliance study re-instated and established the safety and efficacy of Fenfuro® as an effective phytotherapeutic to treat hyperglycemia

Dimer formation by symbiotic donor–acceptor interaction between two molecules of a specially designed dioxomolybdenum(VI) complex containing both donor and acceptor centers – A structural, spectroscopic and DFT study

This work presents a model study for the formation of a dimeric dioxomolybdenum(VI) complex [MoO2L]2, generated by simultaneous satisfaction of acceptor and donor character existing in the corresponding monomeric Mo(VI) complex MoO2L. This mononuclear complex is specially designed to contain a coordinatively unsaturated Mo(VI) acceptor centre and a free donor group, (e.g. –NH2 group) strategically placed in the ligand skeleton [H2L = 2-hydroxyacetophenonehydrazone of 2-aminobenzoylhydrazine]. Apart from the dimer [MoO2L]2, complexes of the type MoO2L·B (where B = CH3OH, γ-picoline and imidazole) are also reported. All the complexes are characterized by elemental analysis, spectroscopic (UV–Vis, IR, 1H NMR) techniques and cyclic voltammetry. Single crystal X-ray structures of [MoO2L]2 (1), MoO2L·CH3OH (2), and MoO2L.(γ-pic) (3) have been determined and discussed. DFT calculation on these complexes corroborates experimental data and provides clue for the facile formation of this type of dimer not reported previously. The process of dimer formation may also be viewed as an interaction between two molecules of a specially designed complex acting as a monodentate ligand. This work is expected to open up a new field of design and synthesis of dimeric complexes through the process of symbiotic donor–acceptor (acid–base) interaction between two molecules of a specially designed monomer