Showing papers by "Indian Association for the Cultivation of Science published in 1994"
TL;DR: The results indicate that methylglyoxal strongly inhibits ADP-stimulated alpha-oxo-glutarate and malate plus pyruvate-dependent respiration, whereas, at a much higher concentration, methyl glyoxal fails to inhibit succinate- dependent respiration.
Abstract: The effect of methylglyoxal on the oxygen consumption of Ehrlich-ascites-carcinoma (EAC)-cell mitochondria was tested by using different respiratory substrates, electron donors at different segments of the mitochondrial respiratory chain and site-specific inhibitors to identify the specific respiratory complex which might be involved in the inhibitory effect of methylglyoxal on the oxygen consumption by these cells. The results indicate that methylglyoxal strongly inhibits ADP-stimulated alpha-oxo-glutarate and malate plus pyruvate-dependent respiration, whereas, at a much higher concentration, methylglyoxal fails to inhibit succinate-dependent respiration. Methylglyoxal also fails to inhibit respiration which is initiated by duroquinol, an artificial electron donor. Moreover, methylglyoxal cannot inhibit oxygen consumption when the NNN'N'-tetramethyl-p-phenylenediamine by-pass is used. The inhibitory effect of methylglyoxal is identical on both ADP-stimulated and uncoupler-stimulated respiration. Lactaldehyde, a catabolite of methylglyoxal, can exert a protective effect on the inhibition of EAC-cell mitochondrial respiration by methylglyoxal. We suggest that methylglyoxal possibly inhibits the electron flow through complex I of the EAC-cell mitochondrial respiratory chain.
79 citations
TL;DR: Stable cubic ZrO2 up to a temperature of 1173 K has been synthesized by a chemical precipitation technique as discussed by the authors, which appears to be driven by particle size, i.e. the x-ray diffraction pattern of such ultrafine cubic particles.
Abstract: Stable cubic ZrO2 up to a temperature of 1173 K has been synthesized by a chemical precipitation technique. Such a stability appears to be driven by particle size. The critical value below which cubic ZrO2 has been found to be stable is 17 nm. The x-ray diffraction pattern of such ultrafine cubic particles is similar to that obtained by stabilization of ZrO2 by the addition of 20 mole % CaO.
62 citations
TL;DR: In this paper, the reaction of Na2PdCl4 with 2-(arylazo)pyridines (A) in ethanol affords yellow complexes of composition [PdACl2] in which the PdCl2 fragment has acis configuration [ν(Pd Cl): 350, 365 cm−1].
52 citations
TL;DR: It has been observed that at high temperatures, Mott's model of phonon-assisted small polaron hopping between nearest neighbors is consistent with the data, while at low temperatures the variable-range-hopping model is valid.
Abstract: Electrical properties of different compositions of lead vanadate glasses are reported in the temperature range 80--500 K. The experimental results are analyzed with reference to theoretical models existing in the literature. It has been observed that at high temperatures, Mott's model of phonon-assisted small polaron hopping between nearest neighbors is consistent with the data, while at low temperatures the variable-range-hopping model is valid. The hopping at high temperatures in the lead vanadate glasses occurs by the nonadiabatic process in contrast to the vanadate glasses formed with conventional network formers. The hopping model of Schnakenberg can predict the temperature dependence of the conductivity data. The percolation model of Triberis and Friedman applied to the small-polaron-hopping regime is also consistent with the data. The consistency of the low-temperature data with the predictions of the different models cannot be distinguished. The various model parameters such as localization length, density of states, etc., obtained from the best fits are found to be consistent with the glass compositions.
48 citations
TL;DR: A stable monolayer of alcohol dehydrogenase (ADH) enzyme has been prepared by spreading an aqueous solution of ADH on a water subphase containing stearic acid monolayers as discussed by the authors.
48 citations
TL;DR: CulnSe2 films with different Cu/In ratios (0.4-1.2) were deposited on glass substrates by three source evaporation techniques in this paper.
34 citations
TL;DR: The clinical status of the patients measured by the symptom-medication scores demonstrated that C. nucifera pollen-allergic patients had significant clinical improvement after CPE-IT in comparison to placebo treatment, and there was no correlation between symptom-Medication scores and changes in specific serum IgE or IgG levels.
Abstract: The effectiveness of Cocos nucifera pollen extract immunotherapy (CPE-IT) was studied in 96 patients allergic to C. nucifera pollen. A placebo-controlled study was performed at random for a period of 6-12 months. The clinical status of the patients measured by the symptom-medication scores demonstrated that C. nucifera pollen-allergic patients had significant (p < 0.005) clinical improvement after CPE-IT in comparison to placebo treatment. Serological study resulted a significant reduction (p < 0.001) of specific IgE and significant elevation (p < 0.01) of specific IgG in post-therapeutic patients' sera which were correlated significantly (r = 0.45, p < 0.001); the changes of the above immunoglobulin levels in the placebo-treated patients were nonsignificant. However, there was no correlation between symptom-medication scores and changes in specific serum IgE or IgG levels.
32 citations
TL;DR: The final-state wave function involves the electron-electron correlation term and satisfies the asymptotic three-body boundary condition of an ionization process for asymmetric geometry, one of the most important factors for the prediction of reliable ionization cross sections.
Abstract: An approach to calculate the triple differential cross sections (TDCS) for ionization of hydrogenic ions by electron impact in the intermediate- and high-energy regime and for asymmetric geometry is proposed. The theoretical model is particularly suitable for asymmetric geometry since the two outgoing electrons are treated on unequal footings. The final-state wave function, in the present prescription, involves the electron-electron correlation term and satisfies the asymptotic three-body boundary condition of an ionization process for asymmetric geometry (i.e., for ${\mathit{k}}_{1}$\ensuremath{\gg}${\mathit{k}}_{2}$). As is well known, this is one of the most important factors for the prediction of reliable ionization cross sections. The long-range Coulomb interaction occurring in the initial channel has been taken into account properly. TDCS results have been computed for ionization of the ${\mathrm{He}}^{+}$ ion for incident energies of 250, 500, and 1000 eV for fixed values of ejected energy (5 eV) and scattering angle (4\ifmmode^\circ\else\textdegree\fi{}). A large recoil peak is noted in the TDCS structure at lower energies (e.g., 250 eV).
29 citations
TL;DR: In this article, the conductivity of PANI particles in a pressed pellet form ranged between 0.03 and 5 S cm−1 depending on the synthesis condition and was best effected in aqueous alcohol media.
28 citations
TL;DR: Work on the reduction of independent variables in the Schr\"odinger equation for two-particle systems from six to three is extended to give a closed expression of the variational equation for states of arbitrary total angular momentum.
Abstract: Work on the reduction of independent variables in the Schr\"odinger equation for two-particle systems from six to three is extended to give a closed expression of the variational equation for states of arbitrary total angular momentum. The method consists of writing the Hamiltonian in six coordinates, by a suitable choice of transformation equations, and evaluating integrals involving real angular-momentum functions. An existing variational equation for P states follows as a special case of the present formalism.
26 citations
TL;DR: The shift of the band gap to higher energies depended on the relative magnitudes of substrate temperature and gas pressure during deposition as mentioned in this paper, and the relative magnitude of temperature and pressure during the sputtering of a ZnTe target was determined.
TL;DR: In this paper, an almost four orders of magnitude resistivity range at room temperature has been obtained by such changes in particle diameters, which can be explained on the basis of an electron tunneling mechanism.
Abstract: Nanocomposites involving iron particles in silica glass matrix have been synthesized by the hot pressing of suitably reduced precursor gel powders. The metal particles have diameters in the range 3.8 to 10.2 nm. An almost four orders of magnitude resistivity range at room temperature has been obtained by such changes in particle diameters. The resistivity in the temperature range 200-340 K shows a fractional temperature dependence with an average value of n ∼ 0.69. The resistivity changes in this temperature region can be explained on the basis of an electron tunneling mechanism.
TL;DR: In this paper, the authors obtained explicit expressions for the absorption coefficient beyond the absorption edge by considering the Franz-Keldysh effect and mechanical stress to be operative simultaneously in the grain boundary regions of polycrystalline semiconductor films.
Abstract: Explicit expressions for the absorption coefficient beyond the absorption edge are obtained by considering the Franz-Keldysh effect and mechanical stress to be operative simultaneously in the grain boundary regions of polycrystalline semiconductor films. The expressions are successfully utilized to explain the tail end of the absorption spectrum of ZnTe films.
TL;DR: In this article, the authors show that polypyrrole (PPy) dispersions are prepared at room temperature by oxidative polymerization using FeCl3 oxidant in the presence of polyvinyl methyl ether (PVME) as stabilizer, and ethanol or aqueous ethanol as the dispersion medium.
TL;DR: In this paper, the authors used steady state and time correlated single photon counting techniques to reveal the nature of the electron transfer (ET) process within excited (or ground) xylenol donor and ground state (excited) well-known acceptor tetracyanoquinodimethane (TCNQ) in highly polar solvent acetonitrile (ACN) at 300 K.
TL;DR: In this article, the glass formation in the binary Fe 2 O 3 -PbO system with high PbO content by studying X-ray diffraction (XRD), infrared (IR) absorption and differential thermal analysis (DTA) was reported.
Abstract: We report glass formation in the binary Fe 2 O 3 -PbO system with high PbO content by studying X-ray diffraction (XRD), infrared (IR) absorption and differential thermal analysis (DTA)
TL;DR: In this article, the authors showed that poly(vinylidene fluoride) and vinylidene fluoride copolymers cocrystallize depending on the structures present in each copolymer.
TL;DR: In this paper, the salting-in agents (LiClO4, CsBr and GnCl) markedly reduce the fluorescence quantum yield (Φf) and lifetime (τf) of CD-bound TNS anion.
TL;DR: In this article, a synergistic system containing bis(diisopropyl)thiophosphoryl disulfide and Noxydiethylene-2-benzothiazole sulfenamide (OBTS) accelerators is presented.
Abstract: Bis(diisopropyl)thiophosphoryl disulfide (DIPDIS), diisopropyl thiophosphoryl-N-oxydiethylene sulfenamide (DIPTOS), diisopropyl thiophosphory)-N-oxydiethylene disulfide (DIPTOD), diisopropyl thiophosphoryl-2-benzothiazole monosulfide (DIBMS), diisopropyl thiophosphoryl-2-benzothiazole disulfide (DIBDS) and bis(diisopropyl)thiophosphoryl monosulfide (DIPMS) react with silica and generate isopropyl alcohol as a result of rubber-DIPDIS-silica interactions. Increasing the amount of DIPDIS in the system brings about a corresponding increase in silica-rubber coupling, resulting in enhancement of ΔTf−ΔTg modulus and tensile strength. The vulcanizates containing 14 mmol DIPDIS and 35 phr of silica exhibit highest torque and tensile strength. This is commensurate with the optimum loading derived from Lee's method. The synergistic system containing DIPDIS and N-oxydiethylene-2-benzothiazole sulfenamide (OBTS) provides a very useful combination of accelerators. The vulcanizates obtained from this system exh...
TL;DR: In this article, a review encompasses the oxidation reactions of various manganese(III) coordinated molecules and the reactions have been categorized primarily with respect to the type of MANGASIII complexes.
TL;DR: In this article, the X-ray structure of [Mn II 2 L]ClO 4 ·H 2 O is reported, which consists of two crystallographically independent but metrically very similar binuclear units.
TL;DR: In this article, a concise stereoselective synthesis of the general furofuran lignan precursor (±)-Samin 1 has been achieved through a radical annulation reaction in good overall yield.
TL;DR: In this paper, excellent regio-and stereoselectivity has been achieved in the hydrogenation of CC bond conjugated to carbonyl group in presence of olefin by ammonium formate/Pd-C system.
TL;DR: In this paper, the fluorescence properties of 4-methyl-2,6-diacetylphenol (MAOH) are examined in 3-methylpentane and quantum yield measurements are made at room temperature and 77 K.
TL;DR: The binuclear complexes of tetraaminodiphenol macrocyclic ligand (H2L) of cobalt and manganese with the composition [M2LX2]βH2O (X = Cl or Br) and of iron(II) with composition [Fe2L(imidazole)2(CH3OH)2](ClO4)2·2CH3HO) have been synthesized and spectroscopically characterized as discussed by the authors.
TL;DR: In this paper, the photo-induced absorption technique has been applied to α-sexithyenil (T6) molecules both in vacuum evaporated films and KBr pellets.
TL;DR: Two allergenically active components present in the Azadirachta indica whole pollen extract have been isolated by sequential ammonium sulfate precipitation, and Immunoblot confirms the IgE-binding activity of the proteins.
Abstract: Two allergenically active components present in theAzadirachta indica whole pollen extract have been isolated by sequential ammonium sulfate precipitation (0–90%), DEAE-Sephadex A-50 ion-exchange chromatography followed by gel filtration through Sephadex G-200 The allergenicity of fractionated materials has been tested by skin prick test and ELISA inhibition which reveal that AIaI and AIaIVb are the major allergens Immunoblot confirms the IgE-binding activity of the proteins Although both fractions are found to be homogeneous by SDS-PAGE, isoelectric focusing produces more than one isoelectric point in AIaI (pI=315, 33 and 35) and AIaIVb (pI=60 and 62) Amino acid analyses of the two allergens, the effect of pH on them and cross-reactivity between them have been discussed
TL;DR: In this paper, the experimental data were analyzed in the light of the grain boundary trapping model in polycrystalline films and the crystallites were found to be partially depleted of carriers.
TL;DR: In this article, the effect of zinc diisopropyl dithiophosphate (ZDC) additive on rubber vulcanization has been investigated in the presence of thiazole-based accelerators.
Abstract: Investigations have been carried out on the effect of several zinc dithiocarbamates in the presence of thiazole-based accelerators in the vulcanization of natural rubber (NR), keeping in mind the possibility of introducing safe dithiocarbamates derived from safe amines. Mutual activity is observed in all the binary systems studied, the highest being observed in the zinc dibenzyldithiocarbamate-dibenzothiazyldisulfide (ZBEC–MBTS)-accelerated system. The effect of zinc diisopropyl dithiophosphate, reportedly a safe rubber additive, which is recognized as an age-resistant agent for NR, on cure has also been studied. The study reveals that thiuram disulfide and MBT are always formed from the reaction either between zinc dithiocarbamate (ZDC) and MBTS or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that 2-mercaptobenzothiazole (MBT) generated from MBTS or CBS reacts with ZDC and produces tetramethyl thinram disulfide (TMTD). The observed mutual activity has been discussed based on the cure and physical data and explained through the results based on HPLC and a reaction mechanism. © 1994 John Wiley & Sons, Inc.
TL;DR: The electrical conductivity of the samples obeys a relation σ(ω)∼ω s with s having values in the range 0.5 to 0.8 as mentioned in this paper.
Abstract: Bismuth substituted barium hexaferrites in the composition series BaO·(6- x ) Fe 2 O 3 · x Bi 2 O 3 with 0< x <0.5 have been prepared and their electrical conductivity measured over the temperature range 325 to 510 K. The ac conductivity of the samples obeys a relation σ(ω)∼ω s with s having values in the range 0.5 to 0.8. The electrical conductivity is believed to arise due to the creation of Fe 2+ sites by the reducing action of Bi 3+ ions. The ac conductivity variation is explained on the basis of overlapping-large-polaron-tunnelling (OLPT) mechanism.