Showing papers by "Jadavpur University published in 1981"
TL;DR: A new more natural definition of proper compactness is given and a few properties resulting from this are established.
87 citations
TL;DR: The study shows that a proper choice of elements in the series is important in studies undertaken to establish the biological effects of solar activity.
77 citations
TL;DR: From the chemical modification studies tryptophan and tyrosine residues are found to be important for the carbohydrate binding activity of M. charantia lectin.
Abstract: A lectin has been isolated from Momordica charantia seeds and purified to homogeneity by affinity adsorption on a cross-linked arabinogalactan column and subsequent elution with 0.1 M lactose. In sedimentation velocity experiments an S20,W(O) degrees value of 6.5 S was obtained for the native lectin and 2.7 S for its subunits obtained by dissociation with 0.1% sodium dodecyl sulphate in the presence of 0.1% 2-mercaptoethanol. This lectin has a molecular weight of 120 000, is tetrameric in nature with two pairs of non-identical subunits of molecular weights 28 000 and 30 000. It is a glycoprotein containing 10% hexoses (2% glucose and 8% mannose) and 2.5% hexosamine, all glucosamine. It has two binding sites per molecule and has Ka values of 4.1 X 10(4) M-1 and 1.8 X 10(4) M-1 at 5 degrees C and 25 degrees C respectively for p-nitrophenyl beta-D-galactopyranoside with delta H degrees and delta S degrees values of --28.3 kJ mol-1 and --12.3J mol-1 K-1 respectively. Hemagglutinating activity of M. charantia lectin is inhibited by galactose and other carbohydrates containing the galactopyranosyl residue. From the chemical modification studies tryptophan and tyrosine residues are found to be important for the carbohydrate binding activity of M. charantia lectin.
45 citations
TL;DR: In this article, the Gibbs energies of transfer of acetonitrile from water to aqueous mixtures of 20, 40, 60 and 80 mass per cents of ACN have been determined at 25°C from emf measurements performed on the double cell comprising AgAg X and M (Hg) electrodes.
38 citations
TL;DR: In this paper, the influence of the thickness on the gap states is interpreted in terms of the density of states model proposed by Mott and Davis, and the amorphous to crystalline transition obtained by heat treatment of the specimen is also investigated.
Abstract: Thin films of amorphous selenium obtained by vacuum evaporation display an increase of “optical gap” E g opt with an increase of thickness of the film. From the observed dependence of E g opt on the thickness of the film, the influence of the thickness on the gap states is interpreted in terms of the density of states model proposed by Mott and Davis. The amorphous to crystalline transition obtained by heat treatment of the specimen is also investigated. The minimum temperature for an appreciable change in crystallisation determined by the transmission of light through selenium films is also a function of the thickness and binding energy of the films. The crystalline structures resulting from heat treatment at different temperatures have been identified by scanning electron microscopy. The generation of different crystalline structures is reported in terms of the thickness and preparation conditions of the amorphous films.
36 citations
TL;DR: The binding of 4-methylumbelliferyl beta-D-galactopyranoside (MeUmb-Galp), to Mormordica charantia lectin was studied by equilibrium dialysis and quenching of ligand fluorescence, showing that the binding of the glycoside takes place in hydrophobic environment.
Abstract: The binding of 4-methylumbelliferyl beta-D-galactopyranoside (MeUmb-Galp), to Mormordica charantia lectin was studied by equilibrium dialysis and quenching of ligand fluorescence. The fluorescence of MeUmb-Galp decreases as a function of solvent polarity. On binding to M. charantia lectin, its fluorescence was nearly 100% quenched, showing that the binding of the glycoside takes place in hydrophobic environment. The binding of the fluorescent sugar was saccharide-specific as evidenced by reversal of MeUmb-Galp fluorescence quenching by lactose. The association constant is independent of the experimental method used and at 25 degrees C the value is (1.96 +/- 0.05) X 10(4) M-1. The number of binding sites as determined by equilibrium dialysis and fluorescence quenching agree very well with each other; n being equal to 1.98 +/- 0.02. The Ka value for the glycoside was also determined by competition studies employing reversal of fluorescence quenching of MeUmb-Galp by lactose. The value of ka obtained for lactose is 1.21 X 10(4) M-1 at 30 degrees C. The internal consistency of the association constant and number of binding site values at low and high saturation indicates the absence of additional subsite on M. charantia lectin. The thermodynamic parameters do not differ greatly with change in temperature; the values of - delta H degrees and - delta S degrees are equal to 30 +/- 9.63 kJ mol-1 and 21 +/- 0.3 J mol-1 K-1 respectively in the range of 15--35 degrees C indicting that the binding of M. charantia lectin to saccharide is exothermic in nature.
34 citations
TL;DR: Results of the application of the fast Fourier transform to respiratory sounds of six normal subjects and six tuberculosis patients suggest that such studies may well prove to be a promising noninvasive diagnostic tool for lung diseases and increase the clinical importance of lung auscultation.
Abstract: The applcation of the fast Fourier transform in the digital analysis of various biological signals in the frequency domain is well-known. In this paper a method is described for spectrum analysis of respiratory sound using the technique of fast Fourier transform. Results of the application of the method to respiratory sounds of six normal subjects and six tuberculosis patients are presented. Such studies may well prove to be a promising noninvasive diagnostic tool for lung diseases and increase the clinical importance of lung auscultation.
27 citations
TL;DR: In this paper, the Gibbs energies of transfer, ΔG°t, of MCl (M = Li, Na, K, Rb and Cs) and K X (X = Br and I) have been determined by use of the double cells comprising M(Hg) and AgXAg electrodes in some aqueous mixtures of DMF at 25°C.
26 citations
TL;DR: In this article, a procedure for constructing a reduced-order observer for a linear time-invariant system defined by a state-space description is presented, which makes use of the concept of generalized matrix inverse and does not presuppose the observer structure.
Abstract: A procedure is presented to construct a reduced-order observer for a linear time-invariant system defined by a state-space description. The construction procedure makes use of the concept of a generalized matrix inverse and does not presuppose the observer structure. Illustrative examples arc included.
24 citations
TL;DR: In this article, the free energies of transfer of ions from water to mixtures of water with acetonitrile (AN), with dimethylformamide (DMF), with DMSO (DMSO), and with ethylene glycol have been determined using both the tetraphenylarsonium tetraphhenylboride (TATB) and the negligible liquid junction potential (QLJP) assumptions.
Abstract: Free energies of transfer of ions from water to mixtures of water with acetonitrile (AN), with dimethylformamide (DMF), with dimethylsulfoxide (DMSO), and with ethylene glycol have been determined using both the tetraphenylarsonium tetraphenylboride [TATB] and the negligible liquid junction potential [E
j
] assumptions By making use of ΔG
tr
(Ag+)[TATB]=12 kJ-mol−1 for transfer from DMSO to AN and by assuming negligible liquid junction potential in the cell
$${\text{Ag|AgNO}}_{\text{3}} {\text{(0}}{\text{01}}M{\text{),S}}\parallel {\text{Et}}_{\text{4}} {\text{NPic(0}}{\text{1}}M{\text{),AN}}\parallel {\text{AgNO}}_{\text{3}} {\text{(0}}{\text{01}}M{\text{),AN|Ag}}$$
single ion free energies of transfer of silver ion ΔG
tr
(Ag+)[E
j
] from DMSO to 35 pure and mixed solvents show a standard deviation of only 2 kJ-mol−1 when compared with ΔG
tr
(Ag+) calculated from the TATB assumption that ΔG
tr
(Ph
4
As+)=ΔG
tr
(Ph
4
B−) The ferrocene assumption [Fc] also gives acceptable agreement with ΔG
tr
(Ag+)[TATB] provided that the solvents are not highly aqueous Other cells with other junctions give less acceptable agreement between the E
j
and TATB assumptions It is essential that the salt bridge is always tetraethylammonium picrate in AN, if the E
j
assumption is assumed Because of the ease of making potentiometric measurements compared with the difficulty of measurements required for the TATB assumption, the negligible liquid junction potential method in the cell shown is recommended for estimating transfer free energies of single ions The ferrocene assumption is acceptable only for non-structured aprotic solvents
20 citations
TL;DR: In this article, the reaction of methanol, ethanol and isopropanol to hexachloroiridate(IV) was studied spectrophotometrically in a sodium acetate-acetic acid buffer.
TL;DR: In this paper, the authors attempted to reduce the thrust by modifying the chisel edge of small drill of both HSS and carbide types, and the results reported in this paper indicate significant improvement.
TL;DR: L -fuzzy sets and, subsequently, L - fuzzy topological spaces are considered in this paper, where L is a complete and completely distributive non-atomic Boolean algebra.
01 Apr 1981
TL;DR: A new digital phase-locked loop system realizale by a few off-the shelf digital ICs is described, characterized by wide locking range and fast capture time down to very low frequencies and suited to low frequency multiplication.
Abstract: A new digital phase-locked loop system realizale by a few off-the shelf digital ICs is described. The system is locked by tracking the input square wave and produces an output binary code whose value is proportional to the input frequency. It is characterized by wide locking range and fast capture time down to very low frequencies (<1 Hz) and suited to low frequency multiplication. Asymmetry in capture time, however, limits its use as an FM demodulator to only slowly varying signals.
TL;DR: In this paper, the spectrophotometric and thermodynamic properties of charge transfer complexes of iodine and aromatic hydrocarbons have been reinvestigated in heptane solvent to make a correlation between the oscillator strength of charge-transfer bands and the heats of formation of the complexes.
TL;DR: Investigations indicate a distinct difference in wave shapes between sound signals recorded from normal and diseased subjects.
Abstract: Respiratory sounds having a pulmonary origin from both normal subjects and tuberculosis patients were recorded and a preliminary analysis was made with a number of bandpass filters. These investigations indicate a distinct difference in wave shapes between sound signals recorded from normal and diseased subjects.
TL;DR: In this paper, an analysis for withdrawal of cylinders from power law fluids has been presented for predicting the withdrawal speed for a desired film thickness, and the theory has been compared with the previously published photographic and flow rate data of a low viscous Newtonian fluid for three values of NGO and shows close agreement up to NCA = 0.7.
TL;DR: In this article, the authors proposed a model in terms of which they have correlated the cohesion, the stability, the phase-transition properties, the elastic and the dielectric properties, and the phonon dispersion of the AgCl crystal.
Abstract: The silver halide crystals have many peculiarities in their physical properties which are uncommon among the simple ionic solids. The different theoretical models used to calculate the properties of this group of solids have concentrated on explaining one or the other of them. But these calculations have one major difficulty common to all. It has not been possible to give a consistent description of the dielectric properties and the dispersion of phonons in the framework of a single model. We have shown from a microscopic analysis of the energy expression of a system of ions occupying arbitrary positions that there exist two types of short-range polarization mechanisms, one arising out of the overlap of the unperturbed wave functions and another due to the perturbation of the wave function. These two effects taken together resolve the incompatibility mentioned above. Based on this analysis we have proposed a model in terms of which we have correlated the cohesion, the stability, the phase-transition properties, the elastic and the dielectric properties, and the phonon dispersion of the AgCl crystal. It is seen that the present model broadly reproduces all the characteristic features of this crystal. Moreover, we have tried to assess in a rough way the relative importance of the different interactions envisaged and their relation to the typicalities of this solid. Finally, some of the limitations of the present calculation are also pointed out.
TL;DR: In this article, 4,6-dimethoxy-1-naphthylalkyl ketones have been used for demethoxylation and autooxidation.
TL;DR: In this article, an instrumentation scheme is developed for simultaneous measurement of the timegapwidth history at various locations of the mold-metal interface during solidification in an ingot casting system.
TL;DR: In this article, the effect of core polarization on the magnetic moment was studied for odd-mass nuclei around N = 50: 85, 87 Kr, 87, 89 Sr, 91 Zr and 89 Y.
TL;DR: Experiment conducted on a microstrip quarterwave antenna structure on a typical ferrite substrate reveals reduction in size, interesting radiation characteristics and a broadband nature over a wide range of frequencies in the lower UHF region.
Abstract: Experiment conducted on a microstrip quarterwave antenna structure on a typical ferrite substrate reveals reduction in size, interesting radiation characteristics and a broadband nature over a wide range of frequencies in the lower UHF region.
TL;DR: In this article, a method was developed for determining the auto-correlation functions of the fluctuations in the transverse and the parallel components of hot carrier-velocity in a semiconductor by Monte Carlo simulation.
Abstract: A method has been developed for determining the auto-correlation functions of the fluctuations in the transverse and the parallel components of hot carrier-velocity in a semiconductor by Monte Carlo simulation. The functions for electrons in InSb are determined by this method for applied electric fields of 50 V/cm, 75 V/cm, and 100 V/cm. With increasing value of the time interval the transverse auto-correlation function falls nearly exponentially to zero, but the parallel function falls sharply to a negative peak, then rises to positive values and finally becomes zero. The interval beyond which the auto-correlation function is zero and the correlation time are also evaluated. The correlation time is found to be approximately 1.6 times the relaxation time calculated from the chord mobility. The effect of the flight sampling time on the value of variance of the displacement, is investigated in terms of the low frequency diffusion constants, determined from the variation of the correlation functions. It is found that the diffusion constants become independent of the sampling time if it is of the order of one hundred times the relaxation time. The frequency-dependent diffusion constants are calculated from the correlation functions. The transverse diffusion constant falls monotonically with frequency for all the field strengths studied. The parallel diffusion constant has similar variation for the lower fields (50 V/cm and 75 V/cm) but it has a peak at about 44 GHz for the field of 100 V/cm.
TL;DR: In this paper, the frequency of any particular genetic type of ripple differs widely when analysed in terms of different dimensionless parameters, e.g., R.I, R.S.I., S.I. etc., processed separately for the two types of ripples, show a wide variation in their range which encompasses the total spectrum of values stipulated for wave and current ripples.
TL;DR: In this paper, the authors presented an investigation of cluster characteristics in nucleon-light nucleus and nucleon heavy nucleus collision in emulsion at ultrahigh cosmic ray energies (above 1 TeV) following a model independent method proposed by Shivpuri et al.
Abstract: In this paper we have presented an investigation of cluster characteristics in nucleon-light nucleus and nucleon-heavy nucleus collision in emulsion at ultrahigh cosmic ray energies (above 1 TeV) following a model independent method proposed in a recent paper by Shivpuri et al. It has been observed that the cluster characteristic in both are not very different from those in case of nucleon-nucleon collision.
TL;DR: In this article, the charge transfer energies of iodine complexes with aromatic hydrocarbons such as benzene, toluene, xylenes (p-, o-and m-), mesitylene and hexamethylbenzene have been measured in different solvents and different values have been obtained in each set of the complexes.
Journal Article•
TL;DR: In this paper, the field-relations, petrography and chemical composition of gabbroanorthosite-granophyre-leucogranite suite supports a co-magmatic origin of these rocks.
Abstract: Study on the field-relations, petrography and chemical composition of gabbroanorthosite-granophyre-leucogranite suite supports a co-magmatic origin of these rocks.