856 research outputs found
Superconductivity in doped FeTe1-xSx (x= 0.00 to 0.25) single crystals
We report self flux growth and characterization of FeTe1-xSx (x= 0.00 to
0.25) single crystal series. Surface X-ray diffraction (XRD) exhibited
crystalline nature with growth in (00l) plane. Micro-structural (electron
microscopy) images of representative crystals showed the slab-like morphology
and near stoichiometric composition. Powder XRD analysis (Rietveld) of single
crystals exhibited tetragonal structure with P4/nmm space group and decreasing
a and c lattice parameters with increase in x. Electrical resistivity
measurements (R-T) showed superconductivity with Tconset at 9.5K and 8.5K for x
=0.10 and x =0.25 respectively. The un-doped crystal exhibited known step like
anomaly at around 70K. Upper critical field Hc2(0), as calculated from magneto
transport for x =0.25 crystal is around 60Tesla and 45Tesla in H//ab and H//c
directions. Thermal activation energy [U0(H)] calculated for x =0.10 and 0.25
crystals followed weak power law, indicating single vortex pinning at low
fields. Mossbauer spectra for FeTe1-xSx crystals at 300K and 5K are compared
with non superconducting FeTe. Both quadrupole splitting (QS) and isomer shift
(IS) for S doped crystals were found to decrease. Also at 5K the hyperfine
field for x =0.10 superconducting crystal is decreased substantially from
10.6Tesla (FeTe) to 7.2Tesla. For x =0.25 crystal, though small quantity of
un-reacted Fe is visible at room temperature, but unlike x =0.10, the low
temperature (5K) ordered FeTe hyperfine field is nearly zero.Comment: 20 Pages Text + Figs: Accepted Mat. Res. Exp, Mat. Rex. Exp. (2018
Bacteriophage burst size during multiple infections
A significant positive correlation was observed between multiplicity of infection and burst size of mycobacteriophage 13. During multiple infections, the average contribution of each infecting phage to the burst size was inversely correlated with multiplicity of infection even when bacterial resources were not limiting. We conclude that the efficiency of phage-coded functions rather than the extent of bacterial resources determines the burst size
Growth of Mycobacterium smegmatis in minimal and complete media
The growth patterns of Mycobacterium smegmat is SN2 in a minimal medium and in nutrient broth have been compared. The growth was monitored by absorbancy (Klett readings), colony forming units, wet weight and content of DNA, RNA and protein. During the early part of the growth cycle, the bacteria had higher wet weight and macromolecular content in nutrient broth than in minimal media. During the latter half of the growth cycle however, biosynthesis stopped much earlier in nutrient broth and the bacteria had a much lower content of macromolecules than in the minimal medium. In both the media, a general pattern of completing biosynthesis rapidly in the initial phase and a certain amount of cell division at a later time involving the distribution of preformed macromolecules was seen. The possible adaptive significance of this observation has been discussed
Evaluation of Hexane Extract of Tuber of Root of Cyperus rotundus Linn (Cyperaceae) for Repellency against Mosquito Vectors
Hexane extract of tuber of plant Cyperus rotundus (Cyperaceae) was screened under laboratory conditions for repellent activity against mosquito vector Anopheles culicifacies Giles species A (Diptera: Culicidae), Anopheles stephensi Liston (Diptera: Culicidae), and Culex quinquefasciatus Say (Diptera: Culicidae). The Cyperus rotundus tuber extract was used to determine their effect on mosquito vector, and comparison with the DEET (NN Diethyl 1-3 methyl Benzamide, formerly known as diethyl 1-m-toluamide). The tuber extracts showed more effective at all the dose. Result obtained from the laboratory experiment showed that the tuber extracts are more effective for repellency of allthe mosquito vector even at low dose. Clear dose response relationships were established with the highest dose of 10% tuber extract evoking 100% repellency. Percent protection obtained against An. culicifacies Giles species A 100% repellency in 4 hours, 6 hours, An. stephensi 100% repellency in 6 hours and Cx. quinquefasciatus was 100% repellency in 6 hours at the 10% concentration. Against DEET- 2.5% An. culicifacies A 100% repellency in 1 hour, 2 hours, 6 hours, An. stephensi have shown 100% repellency in 6 hours, and Culex quinquefasciatus have shown 100% repellency in 1 hour, 2 hours, 6 hours. The consolidated data of the repellency observed in different species is given and it is evident that the over all repellency rates varied between 80 and 100% for different repellents concentrations (2.5%, 5%, and 10%). The extract can be applied as an effective personal protective measure against mosquito bites
Heat capacity and Mosssbauer study of Self flux grown FeTe Single Crystal
We report mainly the heat capacity and Mossbauer study of self flux grown
FeTe single crystal, which is ground state compound of the Fe chalcogenides
superconducting series, i.e., FeTe1-x(Se/S)x. The as grown FeTe single crystal
is large enough to the tune of few cm and the same crystallizes in tetragonal
structure having space group of P4/nmm. FeTe shows the structural/magnetic
phase transition at 70K in both magnetic and resistivity measurements. Heat
capacity measurement also confirms the coupled structural/magnetic transition
at the same temperature. The Debye model fitting of low temperature (below 70K)
heat capacity exhibited Debye temperature to be 324K. M\"Ossbauer spectra are
performed at 300K and 5K. The 300K spectra showed two paramagnetic doublets and
the 5K spectra exhibited hyperfine magnetic sextet with an average hyperfine
field of 10.6Tesla matching with the results of Yoshikazu Mizuguchi et al.Comment: Short MS-12 pages text + figs: Accepted Letter - J. Sup. Novel Ma
Kinetics and mechanism of oxidation of erythro-series pentoses and hexoses by N-chloro-p-toluenesulfonamide
The kinetics and mechanism of oxidation of D-glucose, D-mannose, D-fructose, D-arabinose, and D-ribose with chloramine-T in alkaline medium were studied. The rate law, rate = k Chloramine-T] Sugar] HO-](2), was observed. The rate of the reaction was influenced by a change in ionic strength of the medium, and the dielectric effect was found to be negative. The latter enabled the computation of d(AB), the size of the activated complex. The reaction rate was almost doubled in deuterium oxide. Activation energies were calculated from the Arrhenius plots. HPLC and GLC-MS analyses of the products indicated that the sugars were oxidized to a mixture of aldonic acids, consisting of arabinonic, ribonic, erythronic, and glyceric acids. Based on these data, a plausible mechanism involving the aldo-enolic anions of pentoses and keto-enolic anions of hexoses is suggested. (C) 1998 Elsevier Science Ltd. All rights reserved
The Sheared Central Venous Catheter?
A fractured central venous catheter (CVC) with embolization of the distal fragment may lead to life-threatening complications. We had inserted a right subclavian CVC in a 68-year-old female which upon a follow-up chest X-ray appeared to have been sheared. A guidewire was inserted through the CVC until the J-tip was just beyond the tip of the CVC which were then withdrawn as a single assembly. We suspected that the tip of the guidewire might have been entrapped in the opening of the middle port, which upon withdrawal of the guidewire could have led to CVC folding upon itself and shearing
Biologically active Naneoicglycolate of Aristolochia littoralis Parodi seed extract with anti-bacterial activity induces cytotoxicity and apoptosis in A431 human skin cancer cell line
Aristolochia littoralis Parodi is an important traditional medicinal plant known for centuries. In this study, antibacterial and anti-cancerous properties of seeds of this plant were investigated. Experimentally chloroform, ethanol, and aqueous extracts were screened for antibacterial activity against Escherichia coli and Staphylococcus aureus. The extracts were further analyzed for anticancer activity against human skin carcinoma A431 cell lines by 3-(4,5-dimethylthiazol-2-yl)-2-5- diphenyl tetrazolium bromide (MTT). The fraction comprising the biomolecule responsible for anticancerous activity was purified by TLC and HPLC. It was subjected to 1H NMR, 13C NMR, and Mass spectrophotometer for structural elucidation. The purified active principle was quantitatively evaluated for inducing apoptosis in A431 skin cancer cell line by flow cytometry analysis. Phytochemical analysis of solvent extracts revealed the presence of alkaloids, steroids, carbohydrates, tannins, and resins. Antibacterial activity was observed in the aqueous and ethanol extracts against the test pathogenic bacteria. Among the solvent extracts, chloroform extract revealed a highly significant anticancer/cytotoxic activity on A431 cell lines. The data revealed that the bioactive principle present in the A. littoralis Parodi seed is naneoicglycolate with molecular formula C20H34O4 and was found to be highly cytotoxic at IC50 81.02 µg\mL against A431 cell line. The present study is successful in identifying a novel bioactive principle from an underutilized plant/weed with significant anticancer activity
Boondh: The journey of a raindrop in the drylands
This book gives you glimpses of our work in 13 project sites and also features path breaking
initiatives that were successfully implemented at other sites in India
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