Showing papers by "Indian Institute of Science published in 1970"
TL;DR: In this article, a unified exact analysis for the statics and dynamics of a class of thick laminates is presented, which leads to simple infinite series for stresses and displacements in flexure, forced vibration and "beam-column" type problems and to closed form characteristic equations for free vibration and buckling problems.
770 citations
TL;DR: In this paper, a 3D linear, small deformation theory of elasticity solution by the direct method is developed for the free vibration of simply-supported, homogeneous, isotropic, thick rectangular plates.
444 citations
TL;DR: In this paper, the authors describe the single bubble formation at isolated nozzles both under constant flow and constant pressure conditions, though considerable work still needs to be done in the intermediate region where bubble size is highly influenced by resonance effects.
Abstract: Publisher Summary This chapter describes the single bubble formation at isolated nozzles both under constant flow and constant pressure conditions, though considerable work still needs to be done in the intermediate region where bubble size is highly influenced by resonance effects. The method of dispersion through submerged nozzles, slots, or holes is the simplest and hence the most common. It permits equipment of extremely simple design and leads to reasonably large interfacial areas. Some industrial operations involving bubble and drop formation are extraction, direct-contact heat exchange, distillation, absorption, sparger reactors, spray drying and atomization, fluidization, nucleate boiling, air lifts, and flotation. In all these operations involving bubbles and drops, three stages have to be studied: the formation of bubbles or drops, the movement of bubbles or drops through the continuous phase and possible coalescence therein, and the formation of the interface. Various factors that influence bubble size are experimental set-up, effect of orifice characteristics, chamber volume, submergence, surface tension of the liquid and the wetting properties of the orifice, liquid viscosity, liquid density, gas properties, effect of gas-flow rates, and effect of continuous-phase velocity. The two-phase theory of aggregative fluidization considers the bed to be made up of two parts: a particulate phase wherein the gas flow rate corresponds to that required for incipient fluidization and a bubble phase, which conveys the extra gas through the bed in the form of bubbles.
314 citations
TL;DR: Much of the chemical structure of thiostrepton, a sulphur containing metabolic product of the microorganism Streptomyces azureus, has been determined by X-ray crystallographic techniques.
Abstract: Much of the chemical structure of thiostrepton, a sulphur containing metabolic product of the microorganism Streptomyces azureus, has been determined by X-ray crystallographic techniques.
159 citations
TL;DR: Evidence has been presented to show that LH maintains pregnancy up to day 12 by stimulating steroidogenesis.
Abstract: Administration of specific and wellcharacterized rabbit antisera to ovine luteinizing hormone (LH) to pregnant rats, before day 12 of gestation, resulted in vaginal bleeding followed by resorption of fetuses. This effect of the antiserum could not be reversed by the administration of either ovine prolactin or extracts of day 12 rat placentae. Homotransplantation of 2 pituitaries under the kidney capsule also did not reverse this effect. Whereas 0.25–5 μg estradiol-17β was ineffective, 4 mg of progesterone could overcome the effects of the antiserum. Deprivation of LH even for 2–8 hr was injurious to fetal growth. These effects of the antiserum could be reversed by the simultaneous administration of LH. Thus, evidence has been presented to show that LH maintains pregnancy up to day 12 by stimulating steroidogenesis. Of the 3 gonadotropins (LH, prolactin and FSH) tried, administration of LH during the second half of pregnancy resulted in postponement of parturition. Similar results were obtained with the ad...
128 citations
TL;DR: Administration of the antihypercholesterolaemic drug ethyl α-p-chlorophenoxyisobutyrate depressed the concentration of serum cholesterol and increased liver weight and the liver content of ubiquinone, but the increase was greater in the nuclear than in the mitochondrial protein.
Abstract: 1. The antihypercholesterolaemic drug ethyl α-p-chlorophenoxyisobutyrate when fed to the rat orally or mixed with the diet increased the content of mitochondria in the liver by 50–100%. Other subcellular fractions did not show any significant change. 2. In oxidative activity, respiratory control and phosphorylating ability no significant difference was observed between the mitochondria isolated from the livers of the drug-treated rats and those from normal animals. 3. In agreement with earlier reports, administration of the drug depressed the concentration of serum cholesterol and increased liver weight and the liver content of ubiquinone. However, the increase of ubiquinone was greater in the nuclear than in the mitochondrial protein.
108 citations
TL;DR: The study has been extended, in a limited way, to the conformation of the ring in the amino acid proline, and it is found that any one of the five atoms can be out of plane (either way), with the other four lying nearly in a plane.
77 citations
TL;DR: The isolation of a mycobacteriaiophage capable of mediating transduction in Mycobacterium smegmatis strain SN2 is reported, thus providing an opportunity to study the genetics of myCobacteria.
Abstract: SEVERAL people have studied lysogeny and lysogenic conversion in the advanced prokaryote, Mycobacterium1-3, and presented evidence for reciprocal genetic exchange from the lysogenic to the non-lysogenic state. Biochemical and physiological changes induced by lysogenization of M. phlei with mycobacteriophage B2 have been demonstrated by Juhasz4. We wish to report the isolation of a mycobacteriophage capable of mediating transduction in Mycobacterium smegmatis strain SN2, thus providing an opportunity to study the genetics of mycobacteria.
74 citations
TL;DR: By using (beta[1-(14)C]-oleoyl) lecithin it was shown that the mucosal phospholipase A was specific for the beta-ester linkage of the leCithin molecule.
Abstract: 1. Subcellular distribution and characteristics of different phospholipases of rat intestinal mucosa were studied. 2. The presence of free fatty acid was necessary for the maximal hydrolysis of lecithin (phosphatidylcholine), but there was no accumulation of lysolecithin (1 or 2-acylglycerophosphorylcholine);lysolecithin accumulated when the reaction was carried out in the presence of sodium deoxycholate and at or above pH8.0. 3. The fatty acid-activated phospholipase B as well as lysolecithinase showed optimum activity at pH6.5, whereas for the phospholipase A it was about pH8.6. 4. The bulk of the phospholipase A was present in the microsomal fraction, whereas the phospholipase B and lysolecithinase activities were distributed between the microsomal and soluble fractions of the mucosal homogenate. 5. Phospholipase A was equally distributed between the brush border and brush-border-free particulate fraction, with the brush border having highest specific activity, whereas the other two activities were distributed between the brush-border-free particulate and soluble fractions. 6. Various treatments showed marked differences between the phospholipase A and phospholipase B activities, but not between phospholipase B and lysolecithinase activities. 7. By using (β[1-14C]-oleoyl) lecithin it was shown that the mucosal phospholipase A was specific for the β-ester linkage of the lecithin molecule.
71 citations
TL;DR: In this article, a new formulation for transverse oscillations of uniform beams is presented, where the governing equations are two simultaneous partial integro-dilferential equations, and simpler governing equations to various orders of approximation are deduced.
Abstract: The paper presents a new formulation for transverse oscillations of uniform beams. The governing equations are two SUnultaneous partial integro-dilferential equations. From these equations, simpler governing equations to various orders of approximation are deduced.
Well-known beam equations correspond to some special cases in the present formulation.Introduction of refined shear coefficient in the Timosbenko's theory seems to increase the discrepancy between theory and experiment, whereas the present formulation reduces this
discrepancy. Second-order approximation equations are believed to be adequate for most engineering applications; for more accurate determination of the natural frequency higher-order approximations can be used.
66 citations
01 Jan 1970
TL;DR: In this paper, the authors describe an electrochemical system where an electronic conductor is in contact with an ionic conductor (or electrolyte), which is a material which consists of mobile ions.
Abstract: An electrochemical system (Fig. 2.1) includes two interfaces, at each one of which an electronic conductor is in contact with an ionic conductor (or electrolyte†). The electronic conductor is generally a metal but may well be a semiconductor. The ionic conductor, as the term suggests, is a material which consists of mobile ions.
TL;DR: The distribution of carotenoids, both qualitative and quantitative, during 3 stages of ripening of mango has been studied using chromatographic, spectroscopic and chemical methods as mentioned in this paper.
Abstract: The distribution of carotenoids, both qualitative and quantitative, during 3 stages of ripening of mango has been studied using chromatographic, spectroscopic and chemical methods. There was an increase in content as well as in number of carotenoids during ripening. The present study showed there were 15, 14 and 17 different carotenoids in the unripe, partially ripe and fully ripe mangoes, respectively. Even though phytofluene (39.26%) was the major carotenoid in the partially ripe mango, β-carotene constituted the major carotenoid in the unripe (37.47%) and fully ripe mango (50.64%). cis-β-Carotene was present only in the fully ripe mango. Only the unripe mango contained ζ-carotene, whereas γ-carotene was present in all the 3 stages of ripening. The major xanthophyll present in the unripe mango was mutatoxanthin (9.44%), whereas auroxanthin constituted the major hydroxylated carotenoid of the partially ripe (5.07%) and fully ripe (10.40%) mangoes. The percent of cryptoxanthin dropped to lower levels during ripening. As ripening proceeded, lutein completely is appeared. There were significant quantities of eaxanthin in the partially ripe and fully ripe mango. Epoxy carotenoids such as 5,6-monoepoxy-β-carotene, mutatochrome, cis-violaxanthin, luteoxanthin, mutatoxanthin and auroxanthin were observed in all 3 stages of ripening.
TL;DR: In this article, the buckling loads of axially and laterally loaded piles were investigated using beam vibration functions and Rayleigh-Ritz energy method. But the results were limited to partially and fully embedded piles.
Abstract: Variation of axial force along the embedded length of the piles and boundary conditions have considerable influence on the buckling loads of piles. Partially embedded and some fully embedded piles are vulnerable to buckling. Furthermore, buckling loads are useful in the study of the behavior of axially and laterally loaded piles. Therefore, using beam vibration functions and the Rayleight-Ritz energy method, buckling loads have been obtained for fully and partially embedded piles. Numerical results have been obtained for axial force variation and different boundary conditions assuming constant and linear soil modulus variation with depth for clays and sands, respectively.
TL;DR: In this article, the biosynthesis of β-N-oxalyl-l-α,β-diaminopropionic acid (ODAP) was found to follow the scheme depicted below: {A figure is presented}.
TL;DR: Isolongifolene, C15H24 an artefact from an acid-catalysed rearrangement of longifolenes, is shown to be II as mentioned in this paper.
TL;DR: In this paper, the number of effective sites for bubble formation is found to be a function of surface tension, viscosity, and density of the liquid and the gas flow rate through the disc.
TL;DR: The substrate specificity of the sorghum acid protease was elucidated using synthetic peptides and pancreatic ribonuclease A as substrates in this article, which revealed that the enzyme has a rather narrow and novel specificity requirement.
Abstract: The substrate specificity of the sorghum acid protease was elucidated using synthetic peptides and pancreatic ribonuclease A as substrates. These studies revealed that the enzyme has a rather narrow and novel specificity requirement. The protease specifically cleaves the peptide linkages involving the α-carboxyl group of either aspartic acid or glutamic acid with the release of the acyl portion of these acidic amino acids. Further, the side chain carboxyl groups of aspartic acid and glutamic acid in the peptides should be unsubstituted for the enzyme to act on the peptide, and therefore, glutaminyl and asparaginyl peptides are not cleaved by the enzyme. Studies carried out with performate oxidized ribonuclease and ribonuclease methyl esters have further substantiated the results obtained with the synthetic substrates. These results suggest that the sorghum acid protease will be very valuable in sequence analyses of proteins.
TL;DR: In this article, the properties of perchlorate perchlorates with molecular formulae have been characterized and the properties are discussed in the light of infrared spectra, conductivity in solvents of different polarity, and molecular weight measurements.
Abstract: Antipyrine complexes of TiO2+, ZrO2+, Zr4+, Th4+ and UO2+2 perchlorates with molecular formulae TiO(Apy)4(ClO4)2, ZrO(Apy)3(ClO4)2, Zr(Apy)6(ClO4)4, Th(Apy)7(ClO4)4 and UO2(Apy)5(ClO4)2 have been prepared and characterized. The complexes are stable in air at room temperature and decompose exothermally at ~3OO °C. The i.r. study indicates the bonding of the antipyrine to the metal ion through its carbonyl oxygen. The nature of the bonding of the perchlorate and the stereochemistry of the complexes are discussed in the light of infrared spectra, conductivity in solvents of different polarity, and molecular weight measurements. From the UO2+2 group frequencies, the force constant K and rU-o are found to be 6.29 × 105 dynes/ cm-1 and 1.74 A, respectively.
TL;DR: Cell-free extracts of Aspergillus niger UBC 814 grown in the presence of dl-mandelate oxidized both d(-)- and l(+)-mandelates via benzoylformate and benzaldehyde to benzoate, and the fungal pathway is compared with these systems in bacteria.
Abstract: Cell-free extracts of Aspergillus niger UBC 814 grown in the presence of dl-mandelate oxidized both d(-)- and l(+)-mandelate via benzoylformate and benzaldehyde to benzoate. dl-p-Hydroxymandelate was oxidized, presumably through a parallel pathway, to p-hydroxybenzoate. A particulate d(-)-mandelate dehydrogenase and a supernatant fraction l(+)-mandelate dehydrogenase converted their respective substrates to benzoylformate. Both flavine adenine dinucleotide and flavine mononucleotide showed a stimulatory effect on the activity of the l(+)-mandelate dehydrogenase. Benzoylformate was decarboxylated to benzaldehyde by an enzyme requiring thiamine pyrophosphate for maximal activity. Two benzaldehyde dehydrogenases dependent on nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), respectively, for their activity dehydrogenated benzaldehyde to benzoate. In the presence of reduced NADP (NADPH), benzoate was oxidized via p-hydroxybenzoate and protocatechuate. Reduced NAD could not replace NADPH. Sensitive methods of assay for d(-)-mandelate dehydrogenase and benzoylformate decarboxylase are described. The fungal pathway is compared with these systems in bacteria.
TL;DR: In this article, the authors investigated free convection heat transfer in vertical concentric, cylindrical annuli analytically and experimentally using the approximate double boundary layer model used by Emery and Chu for the case of vertical parallel plates.
TL;DR: Of the various tissues of rats tested for the activity, intestinal mucosa was found to be the most active, with testes, liver, kidneys and spleen following it in decreasing order, and a lysolecithin with a long-chain fatty acid at the 1-position was most efficient.
Abstract: 1. The presence of an active acyl-CoA–lysolecithin (1-acylglycerophosphorylcholine) acyltransferase was demonstrated in rat intestinal mucosa. 2. ATP and CoA were necessary for the incorporation of free [1-14C]oleic acid into lecithin (phosphatidylcholine). 3. The reaction was about 20 times as fast with [1-14C]oleoyl-CoA as with free oleic acid, CoA and ATP. 4. With 1-acylglycerophosphorylcholine as the acceptor, both oleic acid and palmitic acid were incorporated into the β-position of lecithin; the incorporation of palmitic acid was 60% of that of oleic acid. 5. Of the various analogues of lysolecithin tested as acyl acceptors from [1-14C]oleoyl CoA, a lysolecithin with a long-chain fatty acid at the 1-position was most efficient. 6. The enzyme was mostly present in the brush-border-free particulate fraction of the intestinal mucosa. 7. Of the various tissues of rats tested for the activity, intestinal mucosa was found to be the most active, with testes, liver, kidneys and spleen following it in decreasing order.
TL;DR: In this article, the buckling under shear of clamped skew plates is investigated and results for several new plate configurations and loading conditions as well as more accurate results for configurations reported in previous literature are obtained.
Abstract: IN this Note, a condensed version of Ref. 1, only the results are presented. The available results for buckling of clamped skew plates are few and far from complete.2'3 In the present investigation, results for several new plate configurations and loading conditions as well as more accurate results for configurations reported in previous literature are obtained.In general, for a given a/b, the critical values increase with increasing skew angle. The results also confirm the conjecture of Ref. 4 that in the case of buckling under shear (Nxv)> "two critical values exist, the positive shear (one tending to reduce
the skew angle) being numerically greater than the negative
shear. However, reliable values for positive shear could not
be obtained in Ref. 4 because of convergence difficulties.
TL;DR: In this article, the properties of self-aerated flows in open channels are studied by dividing the flow into two zones: (1) wall turbulent zone; and (2) free turbulent zone.
Abstract: Characteristics of self-aerated flows in open channels are studied by dividing the flow into two zones: (1) wall turbulent zone; and (2) free turbulent zone. Theoretical equations developed for air concentration and velocity in the free turbulent zone, starting from the basic equations of motion and continuity are checked with experiments conducted in a tilting flume and the agreement between them is shown to be good. The terms air-water density and air-water velocity are defined and equations are presented correlating them with air concentration. In accordance with the new definitions, Halbronn's method of measuring air-water velocity is modified and used in the investigations. An empirical relationship between bulkage depth and mean air concentration is presented.
TL;DR: In this paper, the authors studied the inception and entrainment of air in self-aerated open channel flows and developed a criterion for the surface eddy to leave the free surface using the energy concept.
Abstract: Inception and entrainment of air in self-aerated open channel flows are studied. For inception to occur surface eddies should leave the free surface and the whole fluid should be turbulent. A criterion for the surface eddy to leave the free surface is formulated using the energy concept. A method to locate the zone of boundary layer emergence to the free surface which causes the whole fluid to be turbulent in the case of flow over free overfall spillways is developed. Using the concept of entrainment, the basic equations for aerated flow down prismatic channels are formulated. Using these equations, several flow characteristics of the uniform aerated flow are studied. The investigations help in computing uniform aerated flow characteristics knowing the non-aerated flow data.
TL;DR: In this paper, a few theoretical estimates and a large number of experimental determination of the solute-vacancy interaction energies, made by different techniques, are available for decomposition of quenched supersaturated alloys.
TL;DR: Inhibition was found to be specific to ubiquinone-9, the natural major homologue in the rat liver; other homologues were ineffective and the site of inhibition was indicated to be between acetyl-CoA and mevalonate.
TL;DR: The increase in ubiquinone in CPIB-fed animals appears to be due to increased synthesis in the initial stages and to decreased catabolism in the later stages, and an inverse relationship was found between the concentration of ubiquin one in the liver and the serum sterol concentration in CP IB-fed rats.
Abstract: 1. Feeding of alpha-p-chlorophenoxyisobutyrate (CPIB) to rats increased ubiquinone concentration in the liver but not in other tissues. The increase was progressive with the time of feeding and related to the concentration of CPIB in the diet. 2. Incorporation of [1-(14)C]acetate, but not of [2-(14)C]mevalonate, into sterols in the liver in vivo or by liver slices in vitro was decreased on feeding the rats with CPIB. However, incorporation of mevalonate into ubiquinone increased. 3. CPIB, when added in low concentrations to liver slices, had no effect on isoprene synthesis from acetate; higher concentrations, however, were inhibitory. 4. No activation of ubiquinone synthesis from mevalonate was observed when CPIB was added to the liver slices synthesizing ubiquinone. 5. The increase in ubiquinone in CPIB-fed animals appears to be due to increased synthesis in the initial stages and to decreased catabolism in the later stages. 6. An inverse relationship was found between the concentration of ubiquinone in the liver and the serum sterol concentration in CPIB-fed rats.