Nitrogen isotopes in mantle-derived diamonds: indications of a multi-component structure

Mantle nitrogen trapped in diamonds is commonly defined by an isotopic composition (δ15N) of ~-5% based on the central tendency of total combustion diamond data that vary from -25 to +18%. We present here the nitrogen isotopic data from stepped combustion of diamonds, which together with data from other mantlederived materials suggest a multi-component structure of diamond-nitrogen. Mantle nitrogen sampled in diamonds apparently has δ15N ~-15%, similar to that observed in mantle xenoliths and mid-oceanic ridge basalts (MORBs), while nitrogen in a minor population of diamonds from China is consistent with contributions from an ocean island basalt like mantle source

Spectral properties of doped bilayer cuprates at finite temperatures

Recently, angle-resolved photoemission spectroscopy measurements on Bi2Sr2CaCu2O8+δ, which possesses two CuO2 layers in the same unit cell, have yielded very interesting results. For the overdoped samples, these results show a splitting of electronic states near k=(π, 0) point of Brillioun zone. On the other hand, no splitting is observed in the underdoped samples. In view of this, the detailed studies including the doping and temperature dependence of the spectral properties become desirable. In this paper, we consider cuprates possessing two CuO2 layers per unit cell. Each layer in the system is described by the t-t'-J model and the two layers are coupled via an intrabilayer hopping term (t ⊥) and an intrabilayer exchange coupling (J ⊥). A self-consistent perturbation approach is used to calculate the electronic spectral function for different values of hole density, hole momentum and temperature. We find that the imaginary part of the self energy is strongly momentum dependent which contradicts the suggestion that the Fermi surface of cuprates may be described by marginal Fermi liquid theory. We have calculated the spectral function for various values of intrabilayer parameters t ⊥ and J ⊥. For larger values of intrabilayer interactions we observe the splitting in the quasi-particle peak at k=(π, 0) which is in agreement with the recent observations. The splitting is also found to be sensitive to the hole concentration as well as the temperature of the system. We have also discussed the reasons why the splitting is absent in underdoped bilayer cuprates at low temperature

Mechanism of Wound-Healing Activity of Hippophae rhamnoides L. Leaf Extract in Experimental Burns

The present investigation was undertaken to evaluate the healing efficacy of lyophilized aqueous leaf extract of Sea buckthorn (Hippophae rhamnoides L., family Elaeagnaceae) (SBT) and to explore its possible mechanism of action on experimental burn wounds in rats. The SBT extract, at various concentrations, was applied topically, twice daily for 7 days. Treatment with silver sulfadiazine (SSD) ointment was used as reference control. The most effective concentration of the extract was found to be 5.0% (w/w) for burn wound healing and this was further used for detailed study. The SBT-treated group showed faster reduction in wound area in comparison with control and SSD-treated groups. The topical application of SBT increased collagen synthesis and stabilization at the wound site, as evidenced by increase in hydroxyproline, hexosamine levels and up-regulated expression of collagen type-III. The histological examinations and matrix metalloproteinases (MMP-2 and -9) expression also confirmed the healing efficacy of SBT leaf extract. Furthermore, there was significant increase in levels of endogenous enzymatic and non-enzymatic antioxidants and decrease in lipid peroxide levels in SBT-treated burn wound granulation tissue. The SBT also promoted angiogenesis as evidenced by an in vitro chick chorioallantoic membrane model and in vivo up-regulated vascular endothelial growth factor (VEGF) expression. The SBT leaf extract had no cytotoxic effect on BHK-21 cell line. In conclusion, SBT aqueous leaf extract possesses significant healing potential in burn wounds and has a positive influence on the different phases of wound repair

Thermo-acoustics and its detection in a premixed flame

A new optical technique based on light-matter interaction is devised in-house to detect thermo-acoustic disturbances generated after ignition and during propagation of a premixed flame front in a half open channel. The technique involves passing a polarized laser light through a medium whose density or refractive index varies due to the passage of acoustic waves and/or flame front and then capturing the leaked depolarised light through an analyser by a photo-detector. The technique is applied to combustor involving premixed flame propagation and tulip inversion. The thermo-acoustic signals and the flame front are distinguished by comparing the oscilloscope signal with high speed photography of the flow-field. Acoustic waves are found to intercept the flame propagation at various axial locations and time instants

Dissociative Autoionization in (1+2)-photon Above Threshold Excitation of H2 Molecules

We have theoretically studied the effect of dissociative autoionization on the photoelectron energy spectrum in (1+2)-photon above threshold ionization(ATI) of H2 molecules. We have considered excitation from the ground state X-singlet-Sigma-g+(v=0,j) to the doubly excited autoionizing states of singlet-Sigma-u+ and singlet-Pi-u+ symmetry, via the intermediate resonant B-singlet-Sigma-u+(v=5,j) states. We have shown that the photoelectron energy spectrum is oscillatory in nature and shows three distinct peaks above the photoelectron energy 0.7 eV. This feature has been observed in a recent experiment by Rottke et al, J. Phys. B, Vol. 30, p-4049 (1997).Comment: 11 pages and 4 figure

An intervention to improve the knowledge of anganwadi workers pertaining to growth monitoring in rural areas of Varanasi district, India

Background: Growth monitoring is one of the important functions of anganwadi workers (AWWs), for which they should have sufficient knowledge and training. With this background it was hypothesized that educational intervention can make a difference in the level of knowledge of AWWs in regard to growth monitoring. The main objective of the study was to evaluate the changes in knowledge of Anganwadi workers regarding growth monitoring through knowledge up-gradation training.Methodology: It was a field based interventional study, which was conducted on 66 AWWs each from Chiraigaon (intervention) and Cholapur (control) blocks of Varanasi district. The primary tool in this study was a pre-designed and pretested interview schedule for collecting information’s pertaining to study objective.Results: The mean score of knowledge was around 19.7 (max. Score was 30) in both the blocks during baseline survey and almost all the AWWs were having either average or good knowledge of growth monitoring. Post intervention a significant (p<0.01) difference has been observed between the mean knowledge scores of AWWs in intervention (25.32±2.44) and control (20.35±2.70) blocks and as much as 48.5% of AWWs were having excellent knowledge about growth monitoring in Chiraigaon block (p<0.01), while the situation was unchanged in Cholapur block.Conclusion: The knowledge up-gradation was found effective in improving the knowledge status of AWWs with regard to growth monitoring.

Photo-damage to Keratinocytes by Quinine Photosensitization under mild Ultraviolet-B Exposure

Simultaneous and sufficient exposure to sunlight and drug cause phototoxic reactions in the skin. In the present study, the photosensitizing activity of quinine (Q) was studied. Evidences obtained by reduction of cell viability, mitochondrial damage, DNA damage, ROS generation, lysosome damage and phosphatidyl serine translocation as a marker of apoptosis indicates that exposure of quinine treated keratinocytes to UV-B radiation results in quinine photosensitization and subsequent reactions which alter normal cellular processes. Quinine absorbs strongly in UV-B region (330 nm). It reduced viability of cells significantly as observed through MTT assay. Reduction of cell viability was confirmed through accumulation of Rhodamine 123 dye which showed that quinine and UV-B treated cells accumulate less than control cells confirmed that mitochondrial membrane potential was disturbed. Increased intracellular ROS production was measured through DCF fluorescence. Early apoptosis was confirmed through phosphatidyl serine translocation in the membrane. Increased lysosome damage was observed through acridine orange accumulation in the lysosmes. Single stranded damage was confirmed through comet assay and apoptosis was confirmed through EB/AO staining.&nbsp; These results show that UV-B radiation elicits phototoxic effects in keratinocytes through reactive oxygen species generation

Consumption of endophyte-infected fescue seed during the dry period does not decrease milk production in the following lactation.

Ergot alkaloids in endophyte-infected grasses inhibit prolactin (PRL) secretion and may reduce milk production of cows consuming these grasses. We investigated the effects of consuming endophyte-infected fescue seed during late lactation and the dry period on mammary growth, differentiation, and milk production. Twenty-four multiparous Holstein cows were randomly assigned to 3 treatment groups. Starting at 90±4 d prepartum, cows were fed endophyte-free fescue seed (control; CON), endophyte-free fescue seed plus 3×/wk subcutaneous injections of bromocriptine (0.1mg/kg of body weight, positive control; BROMO), or endophyte-infected fescue seed (INF) as 10% of the diet on an as fed basis. Although milk yield of groups did not differ before treatment, at dry off (-60 d prepartum) INF and BROMO cows produced less milk than CON. Throughout the treatment period, basal concentrations of PRL and the prepartum increase in plasma PRL were reduced in INF and BROMO cows compared with CON cows. Three weeks after the end of treatment, circulating concentrations of PRL were equivalent across groups. In the subsequent lactation milk yield was not decreased; in fact, BROMO cows exhibited a 9% increase in milk yield relative to CON. Evaluation of mammary tissue during the dry period and the subsequent lactation, by quantitative histology and immunohistochemical analysis of proliferation markers and putative mammary stem or progenitor cell markers, indicated that feeding endophyte-infected fescue seed did not significantly affect mammary growth and development. Feeding endophyte-infected grasses during the dry period may permit effective utilization of feed resources without compromising milk production in the next lactation