From rocksalt to perovskite: a metathesis route for the synthesis of perovskite oxides of current interest

Solid state metathesis reactions between lithium containing rocksalt metal oxides and appropriate lanthanum/alkaline earth metal oxychloride/chloride provide a convenient route for the synthesis of several perovskite oxides of current interest, such as LaCoO3, LaMnO3, AMnO3 and ATiO3 (A = Ca, Sr, Ba). Similarly, metathesis reactions between Li2TiO3/Li2ZrO3 and PbSO4 (instead of PbCl2) yield PbTiO3, PbZrO3 and PbZr1- xTixO3 perovskites. BaPbO3 and superconducting BaPb0.75Bi0.25O3 could also be synthesized by the metathesis reaction between Li2PbO3/Li2(Pb,Bi)O3 and Ba(OH)2·8H2O. Uniformly in all cases, the perovskite oxides were obtained in the form of loosely connected submicron sized particles at considerably lower temperatures than those usually employed for their synthesis by ceramic methods

Comparative assessment of the antioxidant activity and free radical scavenging potential of different parts of Nerium indicum

Context: Reactive oxygen species (ROS) cause damage to cellular components. Antioxidant compounds scavenge or neutralize the ROS and thus have significant role in human health. Aims: The present study 70% methanol extracts of Nerium indicum leaf, stem and root were evaluated for in vitro total antioxidant, radical scavenging activity along with phenolic and flavonoid contents. Methods and Material: The extracts were examined for the scavenging activity of hydroxyl radical, nitric oxide, singlet oxygen, hypochlorous acid, superoxide, peroxynitrite, hydrogen peroxide. The extracts were also tested for their potential as an iron chelating agent, inhibition of lipid peroxidation and total reducing potential. Results: The present study indicates that the total antioxidant, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical and singlet oxygen scavenging potential is in the order of stem>root>leaf. The hydroxyl radical scavenging, hydrogen peroxide scavenging and hypochlorous acid scavenging activity is in the order leaf>stem>root, whereas superoxide scavenging and lipid peroxidation inhibition assay is root>leaf>stem. Miscellaneous results were obtained in the scavenging of other radicals by the extracts, viz., leaf>root>stem for peroxynitrite and iron chelation activity, root>stem>leaf for reducing power and stem>leaf>root for nitric oxide inhibition. The phenolic and flavonoid content is in the following order root>stem>leaf and leaf>stem>root respectively. Conclusions: The present study revealed that the leaf, stem and root extracts of N. indicum are effective free radical scavenger and might be used as a natural source of potent antioxidant

Comparative assessment of the antioxidant activity and free radical scavenging potential of different parts of Nerium indicum

Context: Reactive oxygen species (ROS) cause damage to cellular components. Antioxidant compounds scavenge or neutralize the ROS and thus have significant role in human health. Aims: The present study 70% methanol extracts of Nerium indicum leaf, stem and root were evaluated for in vitro total antioxidant, radical scavenging activity along with phenolic and flavonoid contents. Methods and Material: The extracts were examined for the scavenging activity of hydroxyl radical, nitric oxide, singlet oxygen, hypochlorous acid, superoxide, peroxynitrite, hydrogen peroxide. The extracts were also tested for their potential as an iron chelating agent, inhibition of lipid peroxidation and total reducing potential. Results: The present study indicates that the total antioxidant, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical and singlet oxygen scavenging potential is in the order of stem>root>leaf. The hydroxyl radical scavenging, hydrogen peroxide scavenging and hypochlorous acid scavenging activity is in the order leaf>stem>root, whereas superoxide scavenging and lipid peroxidation inhibition assay is root>leaf>stem. Miscellaneous results were obtained in the scavenging of other radicals by the extracts, viz., leaf>root>stem for peroxynitrite and iron chelation activity, root>stem>leaf for reducing power and stem>leaf>root for nitric oxide inhibition. The phenolic and flavonoid content is in the following order root>stem>leaf and leaf>stem>root respectively. Conclusions: The present study revealed that the leaf, stem and root extracts of N. indicum are effective free radical scavenger and might be used as a natural source of potent antioxidant

Bioequivalence study of two formulations containing 400 mg dexibuprofen in healthy Indian subjects

Objective: This study presents the results of two-period, two-treatment crossover investigations on 24 healthy Indian male subjects to assess the bioequivalence of two oral formulations containing 400 mg of dexibuprofen (CAS 51146-56-6). An attempt was also made to study the pharmacokinetics of dexibuprofen in the local population of Indian origin.Method: Both of the formulations were administered orally as a single dose separated by a one-week washout period. The concentration of dexibuprofen in plasma was determined by a validated HPLC method with UV detection using carbamazepine as internal standard. The formulations were compared using the parameters area under the plasma concentration-time curve (AUC0-t), area under the plasma concentration-time curve from zero to infinity (AUC0-∞), peak plasma concentration (Cmax), and time to reach peak plasma concentration (tmax).Results: The results of this investigation indicated that there were no statistically significant differences between the logarithmically transformed AUC0-∞ and Cmax values of the two preparations. The 90 % confidence interval for the ratio of the logarithmically transformed AUC0-t, AUC0-∞ and Cmax were within the bioequivalence limit of 0.8-1.25 and the relative bioavailability of the test formulation was 99.04 % of that of reference formulationjok?.Conclusion: Thus, these findings clearly indicate that the two formulations are bioequivalent in terms of rate and extent of drug absorption. Both preparations were well tolerated with no adverse reactions observed throughout the study

Magnetic and electric properties of double-perovskites and estimation of their Curie temperatures by ab initio calculations

First principles electronic structure calculations have been carried out on ordered double perovskites Sr_2B'B"O_6 (for B' = Cr or Fe and B" 4d and 5d transition metal elements) with increasing number of valence electrons at the B-sites, and on Ba_2MnReO_6 as well as Ba_2FeMoO_6. The Curie temperatures are estimated ab initio from the electronic structures obtained with the local spin-density functional approximation, full-potential generalized gradient approximation and/or the LDA+U method (U - Hubbard parameter). Frozen spin-spirals are used to model the excited states needed to evaluate the spherical approximation for the Curie temperatures. In cases, where the induced moments on the oxygen was found to be large, the determination of the Curie temperature is improved by additional exchange functions between the oxygen atoms and between oxygen and B' and B" atoms. A pronounced systematics can be found among the experimental and/or calculated Curie temperatures and the total valence electrons of the transition metal elements.Comment: 8 pages, 11 figures. Submitted to the Physical Review

Phyto-chemical Standardization of Herbal Formulation (PMM3) for Blood Sugar Attenuating Actions in Streptozotocin induced Rats

The present study was intended to prepare herbal formulation, PMM3 using purified and modified parts of five common Indian herbs like, Trigonella foenum-graccum, Tinospora cordifolia, Scoparia dulcis, Adhatoda vasica and Cassia occidental. PMM3 was standardized using physico-chemical, phytochemical, UV-VIS spectral, HPTLC, AAS and GC methods. The phenolics and flavonoids contents were assessed. Anti-hyperglycaemic activities of PMM3 was evaluated on Streptozotocin induced (50mg/kg, i.v) diabetic rats. PMM3 (50-150 mg/kg, p.o) exhibited best potentiality in reducing blood glucose within 14 days treatment in comparison with Diabecon® (Himalaya, India) at the same dose. The preset observation identified formulation PMM3 for anti-hyperglycaemic effect

Study of indigenous freshwater fish diversity of Bankura (West Bengal), India with special reference to Clarias batrachus

A study was conducted to determine the ichthyofaunal diversity in Bankura district of West Bengal. The area is traversed by major and minor rivers, feeder channels, numerous ponds, bills, reservoirs which have made this drought-trodden district as the highest producer of aquatic products within the state. Field survey was conducted in randomly selected local markets covering twenty-two blocks of Bankura. Fish sampling was carried out using various conventional fishing gears. The entire region harbours a wide variety of aquatic fishes. A total number of 92 indigenous fish species belonging to 30 families were identified during this study. The Cyprinidae family dominated the population with its 36 varieties followed by Channidae, Siluridae and Bagridae. Sonamukhi block situated in Shali basin; Sarenga and Raipur of Kangsabati basin; Dwarkeshwar and seven bundhs- enriched Bishnupur were the major habitats of small indigenous fishes. This paper also denotes presence of 12 globally endemic freshwater fish species viz. Hypophthalmichthys molitrix, Cyprinus carpio, Labeo nandina, Tor khudree, Chitala chitala, Bagarius bagarius, Wallago attu, Ompok pabda, Ailia coila, Anguilla bengalensis, Parambassis lala, Oreochromis mossambicus. The substitution of native Clarias batrachus with invasive African catfish C. gariepinus was observed in various local markets. Some traders even promote illicit farming of this banned species for their own profit. As a consequence, the indigenous, nutritionally-enriched C. batrachus is becoming more endangered

Experimental assessment of arsenic toxicity in garole sheep in India

Arsenic, a dangerous bio-accumulative poison, is a grave threat affecting a large number of people as well as animals throughout the World, particularly in Bangladesh and West Bengal, India. It is also a matter of concern as continuously entering into food chain through biotic and abiotic products. The present study was conducted to evaluate the experimental effect of arsenic toxicosis on Garole sheep of West Bengal. One group was subjected to oral arsenic exposure @ 6.6 mg Kg−1 over 133 days when rests considered as negative control. Periodical arsenic estimation in wool, urine and feces along with hemato-biochemical alteration were checked thoroughly. It was evident from the study that long term arsenic exposure exerted a significant (p < 0.01) alteration compared to normal animal which were further supported by clinical abnormalities. Exposed animals showed histological changes throughout major internal organs like coagulative necrosis of liver, tubular nephritis of kidney and acanthosis of skin etc. The bio-accumulative and excretion pattern of arsenic inside body were also well understood by the arsenic estimation study of wool, urine and feces which may be helpful for discussion regarding arsenic entry into food chain via animals

The role of flow geometry in influencing the stability criteria for low angular momentum axisymmetric black hole accretion

Using mathematical formalism borrowed from dynamical systems theory, a complete analytical investigation of the critical behaviour of the stationary flow configuration for the low angular momentum axisymmetric black hole accretion provides valuable insights about the nature of the phase trajectories corresponding to the transonic accretion in the steady state, without taking recourse to the explicit numerical solution commonly performed in the literature to study the multi-transonic black hole accretion disc and related astrophysical phenomena. Investigation of the accretion flow around a non rotating black hole under the influence of various pseudo-Schwarzschild potentials and forming different geometric configurations of the flow structure manifests that the general profile of the parameter space divisions describing the multi-critical accretion is roughly equivalent for various flow geometries. However, a mere variation of the polytropic index of the flow cannot map a critical solution from one flow geometry to the another, since the numerical domain of the parameter space responsible to produce multi-critical accretion does not undergo a continuous transformation in multi-dimensional parameter space. The stationary configuration used to demonstrate the aforementioned findings is shown to be stable under linear perturbation for all kind of flow geometries, black hole potentials, and the corresponding equations of state used to obtain the critical transonic solutions. Finally, the structure of the acoustic metric corresponding to the propagation of the linear perturbation studied are discussed for various flow geometries used.Comment: 13 pages. 5 figure