Pressure and current balance conditions during electron beam injections from spacecraft

Electrostatic charging level of a conducting surface in response to injections of electron beams into space plasma is investigated by means of one-dimensional Vlasov code. Injections of Maxwellian beams into a vacuum shows that the surface can charge up to an electric potential phi sub s greater than W sub b, where W sub b is the average electron beam energy. Since Maxwellian beams have extended trails with electrons having energies greater than W sub b, it is difficult to quantify the charging level in terms of the energies of the injected electrons. In order to quantitatively understand the charging in excess of W sub b, simulations were carried out for water-bag types of beam with velocity distribution functions described by f(V) = A for V sub min approx. less than V approx. less than V sub max and f(V) = O otherwise, where A is a constant making the normalized beam density unity. It is found that V sub max does not directly determine the charging level. The pressure distribution in the electron sheath determines the electric field distribution near the surface. The electric field in turn determines the electrostatic potential of the vehicle. The pressure distribution is determined by the beam parameters such as the average beam velocity and the velocity spread of the beam

Anti-Depressant Activity of Zizyphus xylopyrus

The present study was undertaken to investigate the effect of ethanolic extract (ext.), ethyl acetate (EA) fractions and precipitate fraction (ppt.) of total ethanolic extract of Zizyphus xylopyrus on depression in rats. In the present study, the antidepressant effect of Zizyphus xylopyrus was examined using two behavioral models, the forced swimming test (FST) in rats and tail suspension test (TST) in rats.Ethanolic extract when administered at an acute dose of 50 mg/kg of body weight (P<0.01) reduced the immobility time by 10 and 15 seconds as compared to the immobility time of control in both the screening models. Similarly EA reduced latter by 30 and 35 secs. The ppt. fraction showed the best activity, reducing the immobility time by 50 and 60 secs. in both the tests. These results showed that after standard i.e. Imipramine HCl (30 mg/kg), the ppt. fraction is potent amongst all the studied drugsThe present study clearly demonstrated that Zizyphus xylopyrus exerts an antidepressant effect in these two behavioral models. It may be due to present of flavonoids.Keywords: Zizyphus xylopyrus, Flavanoides, forced swimming test, tail suspension test

Anti-Depressant Activity of Zizyphus xylopyrus

The present study was undertaken to investigate the effect of ethanolic extract (ext.), ethyl acetate (EA) fractions and precipitate fraction (ppt.) of total ethanolic extract of Zizyphus xylopyrus on depression in rats. In the present study, the antidepressant effect of Zizyphus xylopyrus was examined using two behavioral models, the forced swimming test (FST) in rats and tail suspension test (TST) in rats.Ethanolic extract when administered at an acute dose of 50 mg/kg of body weight (P<0.01) reduced the immobility time by 10 and 15 seconds as compared to the immobility time of control in both the screening models. Similarly EA reduced latter by 30 and 35 secs. The ppt. fraction showed the best activity, reducing the immobility time by 50 and 60 secs. in both the tests. These results showed that after standard i.e. Imipramine HCl (30 mg/kg), the ppt. fraction is potent amongst all the studied drugsThe present study clearly demonstrated that Zizyphus xylopyrus exerts an antidepressant effect in these two behavioral models. It may be due to present of flavonoids.Keywords: Zizyphus xylopyrus, Flavanoides, forced swimming test, tail suspension test

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

Development of bioconjugated nano-molecules against targeted microbial pathogens for enhanced bactericidal activity

The study reports development of bio-conjugated nano-molecules (BCM's) for enhanced antibacterial activity against targeted pathogens of global concern. The conjugation was achieved with biomolecular interaction of silver clusters with 3-Dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ) which was purified and characterized with TLC which displayed prominent band at R-f 0.5 and HPLC analysis displayed chromatographic peak eluting at (t(R)) 6-8 min. The LC-MS analysis displayed single major peak at t(R) = 4.610 corresponding to molecular ion peak at m/z = 227.19. The developed BCM molecule was determined with UV-Visible spectroscopy which displayed the absorbance peaks of conjugated molecules with shoulder peak observed and morphological characteristics were well defined with TEM analysis which showed cluster formation. The size ranged from 20 to 80 nm in size with majority of the BCM displaying spherical in size. The process of bio-conjugation was further studied with FTIR analysis which corresponded with different vibrational stretches owing to the presence of amide, carbonyl alkynes, nitriles and carboxylic acid groups. The presence of functional moieties was also studied using H-1 and C-13 NMR spectra. The crystalline characteristics was confirmed with XRD analysis which displayed Bragg's intensities along with additional peaks occurring at 2 theta angle corresponds to (111), (200), (220), (311) face centric cube of silver planes. The antibacterial activity of BCM's was profound against all the test pathogen which was validated and compared with standard antibiotics. Among the test pathogens, highest activity was conferred against Staphylococcus epidermidis (MTCC 435) with 29 mm. The minimal inhibition concentration of BCM's was in the range of 0.97-3.12 mu g/ml. The results of MIC were in accordance with well diffusion assay indicating the Gram + ve test pathogen Staphylococcus epidermidis to be the most sensitive. In addition, the broth dilution assay resulted in decrease in the optical density measured at 600 nm against the increase in the concentration of BCM's. The outcome of the present investigation revealed the role of bio-conjugation chemistry to increase fold activity against pathogens which can act as alternative tool to combat drug resistant menace across the globe

Modulation of T cell cytokine profiles and peptide-MHC complex availability in vivo by delivery to scavenger receptors via antigen maleylation

We have previously shown that conversion of proteins to scavenger receptor (SR) ligands by maleylation increases their immunogenicity. We now show that maleyl-Ag-immune spleen cells make relatively more IFN-ϒ and less IL-4 or IL-10 than native Ag-immune cells. This is also reflected in the IgG1:IgG2a ratios in Abs generated in vivo. SR engagement on macrophages does not alter their surface levels of the adhesive/costimulatory molecules CD11a/CD18, CD11b/CD18, CD24, CD54, or CD40, nor does it enhance their ability to support anti-CD3-driven proliferation of naive T cells in vitro. Costimulatory molecules implicated in differential Th1/Th2 commitment-CD80, CD86, and IL-12-are not inducible by SR ligation. In addition to macrophages and dendritic cells, B cells also show receptor-mediated uptake and enhanced presentation of maleyl-Ags. Using a monoclonal T cell line to detect peptide-MHC complexes expressed on spleen cells in Ag-injected mice, we find that higher levels of these complexes are generated in vivo from maleyl-proteins and they persist longer than those generated from the native protein. Together, these data suggest that in certain situations, the levels of cognate ligand available and/or the time course of their availability may play a major role in determining the cytokine profiles of the responding T cells in addition to the costimulatory signals implicated so far

Functionally relevant microsatellites in sugarcane unigenes

<p>Abstract</p> <p>Background</p> <p>Unigene sequences constitute a rich source of functionally relevant microsatellites. The present study was undertaken to mine the microsatellites in the available unigene sequences of sugarcane for understanding their constitution in the expressed genic component of its complex polyploid/aneuploid genome, assessing their functional significance <it>in silico</it>, determining the extent of allelic diversity at the microsatellite loci and for evaluating their utility in large-scale genotyping applications in sugarcane.</p> <p>Results</p> <p>The average frequency of perfect microsatellite was 1/10.9 kb, while it was 1/44.3 kb for the long and hypervariable class I repeats. GC-rich trinucleotides coding for alanine and the GA-rich dinucleotides were the most abundant microsatellite classes. Out of 15,594 unigenes mined in the study, 767 contained microsatellite repeats and for 672 of these putative functions were determined <it>in silico</it>. The microsatellite repeats were found in the functional domains of proteins encoded by 364 unigenes. Its significance was assessed by establishing the structure-function relationship for the beta-amylase and protein kinase encoding unigenes having repeats in the catalytic domains. A total of 726 allelic variants (7.42 alleles per locus) with different repeat lengths were captured precisely for a set of 47 fluorescent dye labeled primers in 36 sugarcane genotypes and five cereal species using the automated fragment analysis system, which suggested the utility of designed primers for rapid, large-scale and high-throughput genotyping applications in sugarcane. Pair-wise similarity ranging from 0.33 to 0.84 with an average of 0.40 revealed a broad genetic base of the Indian varieties in respect of functionally relevant regions of the large and complex sugarcane genome.</p> <p>Conclusion</p> <p>Microsatellite repeats were present in 4.92% of sugarcane unigenes, for most (87.6%) of which functions were determined <it>in silico</it>. High level of allelic diversity in repeats including those present in the functional domains of proteins encoded by the unigenes demonstrated their use in assay of useful variation in the genic component of complex polyploid sugarcane genome.</p

Cloning and functional validation of early inducible Magnaporthe oryzae responsive CYP76M7 promoter from rice

Cloning and functional characterization of plant pathogen inducible promoters is of great significance for their use in the effective management of plant diseases. The rice gene CYP76M7 was up regulated at 24, 48, and 72 hours post inoculation (hpi) with two isolates of Magnaporthe oryzae Mo-ei-11 and Mo-ni-25. In this study, the promoter of CYP76M7 gene was cloned from rice cultivar HR-12, characterized and functionally validated. The Transcription Start Site of CYP76M7 was mapped at 45 bases upstream of the initiation codon. To functionally validate the promoter, 5′ deletion analysis of the promoter sequences was performed and the deletion fragments fused with the β-glucuronidase (GUS) reporter gene were used for generating stable transgenic Arabidopsis plants as well as for transient expression in rice. The spatial and temporal expression pattern of GUS in transgenic Arabidopsis plants and also in transiently expressed rice leaves revealed that the promoter of CYP76M7 gene was induced by M. oryzae. The induction of CYP76M7 promoter was observed at 24 hpi with M. oryzae. We report that, sequences spanning -222 bp to -520 bp, with the cluster of three W-boxes, two ASF1 motifs and a single GT-1 element may contribute to the M. oryzae inducible nature of CYP76M7 promoter. The promoter characterized in this study would be an ideal candidate for the overexpression of defense genes in rice for developing durable blast resistance rice lines