Showing papers by "Banaras Hindu University published in 1975"
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TL;DR: The model takes into account two main characteristics of ageing: deterioration of adaptability of an organism to environment after maturity and determination of life span of a species.
91 citations
77 citations
TL;DR: This study was designed to test the hypothesis that the impairment of AChE induction in the brain of old rats may be due to a decrease in the level of this receptor, and the data show that it may be correct.
Abstract: WE have shown1,2 that the administration of 17β-oestradiol to ovariectomised female raits induces acetylcholinesterase (AChE; EC 3.1.1.7) in the cerebral hemisphere and cerebellum, and that this induction decreases with increasing age. The greatest induction occurs in the immature rat, and there is no induction in the old. As 17β-oestradiol receptors are present in rat brain3,4, we suggested that the impairment of AChE induction in the brain of old rats may be due to a decrease in the level of this receptor. This study was designed to test our hypothesis, and the data show for the first time that it may be correct.
69 citations
TL;DR: In this paper, a facility for studying time-dependent deformation was created at the University of Melbourne to achieve a constant temperature in the creep testing laboratory and a long-term loading machine consisting of a gas-hydraulic system and a loading frame was designed to apply the sustained pressure on the rock specimens.
58 citations
TL;DR: In this article, a generalized average shear-stress-shear-rate relationship is derived and found to predict the flow behavior of power law as well as non-power law fluids.
51 citations
TL;DR: The influence of polycrystal grain size in the range 18 µm to 184 µm on the tensile behavior of an austenitic stainless steel containing by wt pct 21 Cr, 14 Mn, 0.68 N and 0.12 C was investigated over the temperature range 298 to 1273 K as mentioned in this paper.
Abstract: The influence of polycrystal grain size in the range 18 µm to 184 µm on the tensile behavior of an austenitic stainless steel containing by wt pct 21 Cr, 14 Mn, 0.68 N and 0.12 C has been investigated over the temperature range 298 to 1273 K. Decreasing grain size has been shown to increase the flow stress at small strains in accordance with the Hall-Petch relationship at temperatures up to 873 K. The variation of the Hall-Petch constants with temperature is influenced by dynamic strain ageing between 575 and 775 K. Above 875 K, especially at low strain-rates a reversal of the Hall-Petch correlation occurs and the flow stress decreases with decreasing grain size. The relationship between ductility and temperature is marked by a minimum ductility at about half the absolute melting temperature and intergranular cavitation is observed. A decrease in grain size generally enhanced the ductility in this temperature regime whilst at fine grain sizes this trend was reversed. These results are explained in terms of a combination of a Griffith-Orowan type fracture criterion and an intergranular void sheet mechanism of fracture.
48 citations
48 citations
TL;DR: In this article, it is shown that the parent matrix may contain stacking faults near its surface at the time of the origin of the screw dislocation ledge, which can drastically affect the structure of the resulting polytype.
Abstract: The origin of polytype structures has been attributed to spiral growth round suitable screw dislocations created in a basic structure. In deducing the different polytype structures that can result from such a mechanism, the basic structure has always been assumed to be perfect. It is shown that it is necessary to consider the possibility that the parent matrix may contain stacking faults near its surface at the time of the origin of the screw dislocation ledge. This can drastically affect the structure of the resulting polytype. The most probable fault configurations that can occur in a parent 4H or 2H structure of CdI 2 have been deduced from a calculation of the stacking fault energies. Polytype structures originating from single screw dislocations created in a faulted 2H or 4H matrix containing one of the more probable fault configurations near the surface have been deduced. It is shown that all the observedpolytype structures of CdI 2 can result from such a mechanism and represent structures with minimum, or close to minimum, stacking fault energy. There is an excellent agreement between the structures deduced on the basis of the faulted matrix model and those actually observed. It has been possible to explain the origin of the observed structure series in CdI 2 and the limitation of the Zhdanov numbers to 1, 2 and 3. It is possible to predict theoretically the more probable structures for a polytype, which greatly simplifies its structure determination.
34 citations
33 citations
TL;DR: Morphology of the fruiting structures indicated identity of the pathogen in its conidial stage with Stemphylium vesicarium (Wallroth) Simmons and in the perithecial stage with Pleospora allii (Rabenh.) Ces.
Abstract: A foliar blight disease of onion (Allium cepa L.) and garlic (Allium sativum L.) hitherto unreported from India has been described from Varanasi, U. P. The infection is confined to the leaves and inflorescence stalks. The conidial stage of the pathogen is more injurious to the plants, whereas the perithecial stage occurs on the inflorescence stalks in isolated locations. The conidiophores and conidia typical of the genus Stemphylium Wallroth are formed during the early development of the disease followed by perithecia predominantly developing on the peduncles. The perithecia were also induced to develop in artificial culture and were identical in diagnostic characters to those from the field. The conidia and ascospores from both host and artificial culture were reciprocally pathogenic to onion and garlic. Morphology of the fruiting structures indicated identity of the pathogen in its conidial stage with Stemphylium vesicarium (Wallroth) Simmons and in the perithecial stage with Pleospora allii (Rabenh.) Ces. and de Not., to which they are referred respectively.
33 citations
TL;DR: In this paper, the significance of polyoxygenated xanthones occurring in the Swertia is appraised, and 1.3,7,8-Tetrahydroxyxanthone, 1.7, 8-trihydroxy-3-methoxyxanthones, 1,8,dihydroxy- 3,7-dimethoxy xanthone has been detected by analytical TLC.
TL;DR: In this article, the authors considered the possibility that the parent matrix may contain stacking faults near its surface at the time of the origin of the screw dislocation ledge and deduced the most probable fault configurations that can occur in a parent 4H or 2H structure of CdI2.
Abstract: The origin of polytype structures has been attributed to spiral growth round suitable screw dislocations created in a basic structure. In deducing the different polytype structures that can result from such a mechanism, the basic structure has always been assumed to be perfect. It is shown that it is necessary to consider the possibility that the parent matrix may contain stacking faults near its surface at the time of the origin of the screw dislocation ledge. This can drastically affect the structure of the resulting polytype. The most probable fault configurations that can occur in a parent 4H or 2H structure of CdI2 have been deduced from a calculation of the stacking fault energies. Polytype structures originating from single screw dislocations created in a faulted 2H or 4H matrix containing one of the more probable fault configurations near the surface have been deduced. It is shown that all the observedpolytype structures of CdI2 can result from such a mechanism and represent structures wi...
TL;DR: It seemed likely that cell cultures of other plant species with a low chromosome number, n = 7 or less, would show a selection for diploid cells, but this did not occur in Picea glauca Voss.
Abstract: CHANGES in the number and structure of chromosomes of plant cells cultured in vitro are of common occurrence1, and cell populations devoid of diploid karyotype have been reported2–4. The chromosome number is known to become variable even in clones derived from single cells5,6. In the case of Picea glauca Voss. (n = 21) callus cultures, a positive correlation between growth rate and chromosome number was observed7, which indicates a selection for polyploid cells. Only diploid cells were, however, observed in mitosis in suspension cultures of Haplopappus gracilis (Nutt.) Gray (n = 2) (ref. 2), Medicago sativa L. (n = 16) (ref. 8) and Crepis capillaris L. Wallr. (n = 3) (ref. 9). This could result from polyploid cells dividing less frequently than diploid cells, as diploid and polyploid cells differ physiologically. A strong selection for diploid cells was observed10 in Vicia hajastana Grossh. (n = 5) suspension cultures initiated from mature seeds. It therefore seemed likely that cell cultures of other plant species with a low chromosome number, n = 7 or less, would show a selection for diploid cells.
TL;DR: The whole plant of Swertia bimaculata Hf. as discussed by the authors has been shown to contain four tetra-and five penta-oxygenated xanthones, three of which were previously unreported in nature.
TL;DR: Both acid and alkaline DNases exhibited maximum activity during embryonic life, i.e. at a time when rapid cellular proliferation was occurring, thus exhibiting no correlation to the high level of DNA found in the old brain.
Abstract: —The levels of DNA, RNA, protein and activities of acid and alkaline DNases in developing and old chicken brain were studied. A rapid increase in DNA content was found in the embryonic brain until just prior to hatching. Thereafter, with a transient plateau around the day of hatching, the DNA continued to increase but at a very slow rate. Two-year-old brain was found to have a markedly higher level of DNA as compared to the 10th day postnatal value. RNA showed a steady increase up to the 20th day of embryonic life. Protein levels showed a gradual increase throughout the period studied. Both acid and alkaline DNases exhibited maximum activity during embryonic life, i.e. at a time when rapid cellular proliferation was occurring. With advancing age, the acid DNase activity showed a marked decline thus exhibiting no correlation to the high level of DNA found in the old brain. The alkaline DNase activity, however, was still at a significant level in the 2-year-old brain.
TL;DR: This is the first time that pentaoxygenated xanthones have been found in a member of the genus Swertia, and 1-Hydroxy-3,4,7,8-tetramethoxyxanthone was previously known only as a synthetic compound.
TL;DR: In this paper, the phase diagram of the pseudo-binary system PbTe-GeTe has been synthesized based on solution thermodynamics and the results are in confirmity with a pseudo-isomorphous system having a solid state miscibility gap.
Abstract: Some of the uncertainties concerning phase equilibria in the pseudo-binary system PbTe-GeTe have been clarified in this thermodynamic and constitutional investigation. The heats of fusion of PbTe, GeTe and Pb0.2 Ge0.8 Te have been determined in a differential thermal analysis calorimeter. Based on these results and solution thermodynamics, the phase diagram of the system has been synthesized. Evidence for spinodal decomposition in this system has been presented for the first time with the aid of X-ray diffraction as well as transmission and scanning electron-microscopic data. The results are in confirmity with a pseudo-isomorphous system having a solid state miscibility gap.
TL;DR: In this article, different intrinsic and extrinsic fault configurations that can occur in the close-packed 6H structure, ABCACB, are considered and their stacking fault energies calculated to determine the relative probability of their occurrence.
TL;DR: In this paper, the reactions of titanium and ziroconium tetrahalides with isonicotinic acid hydrazide (INH), acetyl isonic-isonic-acid hydrazides (AINH), and benzoyl isonic-, BINH, have been carried out under anhydrous conditions.
TL;DR: In this paper, the free energy of formation was calculated by the analyses due to Wagner and Jordan using this heat of fusion and liquidus data, and the experimentally determined value of the heat of formation and the calculated free energy was combined to obtain the entropy of formation.
Abstract: The heats of formation and fusion of SnTe were determined in a differential thermal analysis calorimeter. Its free energy of formation was calculated by the analyses due to Wagner and Jordan using this heat of fusion and liquidus data. The experimentally determined value of the heat of formation and the calculated free energy of formation were combined to obtain the entropy of formation. The thermodynamic properties were interpreted in terms of the structure and bonding of the compound.
TL;DR: In this article, it is suggested that this period is an indication of the duct-life times at low L -values, and it is pointed out that power spectrum analyses may not be applicable to whistler data corresponding to high L-values.
TL;DR: In this paper, electrical resistivity measurements at room temperature on dysprosium films in the thickness range 200-1000 A were carried out and the observed thickness dependence of the resistivity in the present case was interesting because, in marked contrast with results for other thin films, the resistivities for Dy thin films decreases at lower thicknesses.
TL;DR: Coordination compounds formed by zinc, cadmium and mercury halides and pseudohalides with 1,3-propanediamine, 1,4-butanediamine (putrescine) and 1,5-pentanediamines (cadaverine) have been prepared and characterized by molecular conductance and infrared spectral measurements down to 200 cm−1 as mentioned in this paper.
Abstract: Coordination compounds formed by zinc(II), cadmium(II) and mercury(II) halides and pseudohalides with 1,3-propanediamine, 1,4-butanediamine (putrescine) and 1,5-pentanediamine (cadaverine) have been prepared and characterized by molecular conductance and infrared spectral measurements down to 200 cm−1. Possible structures for these complexes in the solid state are discussed.
TL;DR: In this paper, the formation of FeSe alloy films as a result of the co-deposition of Se and Fe thin films has been studied and the effect of annealing on this FeSe phase has been investigated.
TL;DR: Two distinct karyotypes in morphologically hardly distinguishable pygmy mice collected from the same rice fields in Varanasi in North India were encountered, which seemed to be due to variation in the quantity of C-band positive constitutive heterochromatin of the autosomal short arms.
TL;DR: In this paper, it is shown that the growth of such anomalous structures cannot be understood in terms of spiral growth round a single screw dislocation in a basic matrix. But this anomaly can be resolved if the basic matrix is assumed to contain stacking faults near the surface at the time of the origin of the screw dislocations ledge.
TL;DR: Anaphase analyses showed that the frequency of anomalies, especially bridges, was negatively associated with the 2,4-D concentration.
Abstract: Suspension cultures ofVicia hajastana andHaplopappus gracilis were maintained in B5 medium containing 0.1, 1.0 and 10.0, and 0.1, 0.5, 1.0 and 5.0 μg/ml 2,4-D, respectively. Anaphase analyses showed that the frequency of anomalies, especially bridges, was negatively associated with the 2,4-D concentration.
TL;DR: In this article, the influence of angle-dependent pair interactions and three-body non-additive interactions on the Helmholtz free energy and on the pair and triplet distribution functions, in some cases through the third order of the perturbation theory, is evaluated.
Abstract: The application of perturbation theory to a fluid of non-spherical molecules of arbitrary symmetry is considered. The influence of a large number of angle-dependent pair interactions and three-body non-additive interactions on the Helmholtz free energy and on the pair and triplet distribution functions, in some cases through the third order of the perturbation theory, is evaluated. Explicit expressions are given for the Helmholtz free energy for molecules possessing axial and tetrahedral symmetries in terms of molecular parameters and the reference systems pair and triplet distribution functions. The contributions of the various terms discussed in this paper are expected to be substantial at low temperatures for a real fluid.
TL;DR: The concentration of plasma protein, FFA, esterified fatty acids and TG in the plasma and liver, which decreases, are increased and decreased, respectively, when compared to intact snakes following the administration of l -thyroxine into thyroidectomized snakes.
TL;DR: In this article, an attempt is made to solve Bonnor's field equations in the spherically symmetric case and it is shown that the solution becomes singular of two finite nonzero values analogous to the Reissner-Nordstrom solution in general relativity.
Abstract: It is well known that the field equations in Einstein’s unified field theory of 1953 do not lead to the Lorentz equations of motion for electromagnetic charges. Bonnor remedied this defect by proposing a modified set of the field equations. In this paper an attempt is made to solve Bonnor’s field equations in the spherically symmetric case. The general solution of these equations in the magnetostatic case is obtained. It is found that when Bonnor’s constantp is taken to be real, the solution becomes singular of two finite nonzero values ofr analogous to the Reissner-Nordstrom solution in general relativity. On the other hand, whenp is imaginary, the solution has a finite nontrivial singularity of Schwarzschild’s type. The field equations have been solved in the magnetic case also, though the solution in this case reduces to the corresponding static solution under the usual boundary conditions. Further, it is shown that Bonnor’s theory does not favour the existence of a nonstatic spherically symmetric isolated system containing electric charge and current.