Browsing by Issue Date, starting with "1991"

Now showing 1 - 20 of 360

Serum malate dehydrogenase (MDH) in portal hypertension--its value as a diagnostic and prognostic indicator.
(1991) M.K. Misra; A.K. Khanna; R. Sharma; S. Srinivasan
Serum MDH levels were estimated in 29 consecutive patients of portal hypertension with the objective of ascertaining its diagnostic value as to the cause of portal hypertension and its prognostic significance. Higher levels of serum MDH were found in cirrhotic patients as compared to noncirrhotic ones. There were however no significant differences found in the values when extrahepatic obstruction group was compared with controls. Furthermore, higher MDH activity was found in those patients who died as compared to the surviving ones.
Studies on Photosynthesis, the Associated Electron Transport System and Some Physiological Variables of Chlorella vulgaris Under Heavy Metal Stress
(1991) L.C. Rai; A.K. Singh; Nirupama Mallick
Results are presented to document the effects of different concentrations of zinc (ZnCl2) and mercury (HgCl2) on different processes of Chlorella vulgaris. The effective concentrations of Hg and Zn reducing 50 per cent (LC50) of the population of the test organism were found to be 0.5 and 2.0 µg mL-1, respectively. These concentrations of Hg and Zn reduced growth, CO2 fixation, O2 evolution, ATP content and NR activity by 56, 64, 75, 89 and 91 % and 50, 36, 57, 79 and 90 %, respectively. The test metals were also found to be highly toxic for nutrient (NO3- and NH4+) uptake. PS II was found to be the primary site of action for the two metals. A possible mechanism of Hg and Zn toxicity is discussed. © 1991, Gustav Fischer Verlag, Stuttgart. All rights reserved.
Urethro-venous intravasation during retrograde urethrography (report of 5 cases).
(1991) S.K. Gupta; B. Kaur; R.C. Shulka
Five instances of urethro-venous intravasation during retrograde urethrography are reported. Four cases were of urethral strictures and one case was of urethral hemangioma. All patients had post procedural bleeding while one patient got allergic reactions, another showed chills and rigors. Anatomy of the drainage veins is described. Factors responsible for this complication and its clinical implications are discussed. It is suggested that urethro-venous intravasation should be considered a diagnostic sign of urethral inflammation.
Synthesis and Evaluation of 2-Imino-3-(4-arylthiazol-2-yl)-4-thiazolidinones and Their 5-Arylidene Derivatives as Potential Fungicides
(1991) Ram Lakhan; Ram Lakhan Singh
A series of new 2-imino-3-(4-arylthiazol-2-yl)-4-thiazolidinones and their 5-arylidene derivatives have been synthesized from 2-amino-4-arylthiazoles as starting materials. The reaction mechanism has also been critically examined. Of all the synthetic compounds tested against Trichoderma harzianum and Curvularia lunata, two of them, namely 2-imino-3-(4-p-chlorophenylthiazol-2-yl)-4-thiazolidinone and 5-benzylidine-2-imino-3-(4-p-tolylthiazol-2-yl)-4-thiazolidinone, exhibited the most potent fungicidal effect. © 1991, American Chemical Society. All rights reserved.
Microbial C, N and P in dry tropical forest soils: Effects of alternate land-uses and nutrient flux
(1991) S.C. Srivastava; J.S. Singh
The effects of alternate land-uses (savanna, cropfield and mine spoil) on microbial C, N and P in dry tropical forest soil of India were studied. The mean microbial C, N and P, respectively, in the four major systems ranged from 250 to 609 μg C g-1, 27 to 65 μg N g-1 and 12 to 26 μg P g-1. The microbial biomass in these systems was characterized by a mean C:N:P ratio of 23:2:1. The microbial C, N and P were positively related to root biomass and total plant biomass (aboveground + root biomass). The derived ecosystems (savanna, cropland and mine spoil) have changed from the original forest ecosystems in terms of soil features and microbial biomass. The conversion of forest into other land-uses resulted in remarkable decline in the amounts of soil nutrients and microbial C, N and P. The microbial nutrients in this dry tropical environment are sensitive to land-use changes. The calculated flux of N and P through the microbial biomass ranged from 27 to 64 kg N ha-1 yr-1 and 13 to 26 kg P ha-1 yr-1. Thus, in this dry tropical environment the microbial biomass appears to contribute substantially to the N and P requirements of higher plants. © 1991.
Microstructural changes in a service exposed CrMoV rotor steel subjected to high temperature low cycle fatigue
(1991) A. Joarder; N.S. Cheruvu; D.S. Sarma
The influence of low cycle fatigue (LCF) deformation on the microstructure of a CrMoV rotor steel service exposed at 510°C for 23 years has been investigated by conducting transmission electron microscopy studies on thin foils made from shoulder and gage sections of the fatigue specimens tested at 538°C using different strain ranges with or without 1 h hold period. The LCF deformation has led to the spheroidisation of coarse cementite present along the grain boundaries as well as within the bainitic ferrite, a slight coarsening of vanadium-rich MC type carbide and profuse precipitation of molybdenum rich M2C type carbide as fine platelets. Increasing strain range or superimposing hold period at the peak tensile load during LCF testing has accelerated these changes.
Pathological review of melanotic neuroectodermal tumour of infancy in India.
(1991) N.C. Aryya; B.L. Rastogi; A.N. Gangopadhyay
Melanotic neuroectodermal tumour of infancy (MNETI) is a rare occurrence. Review of literature indicated 14 cases of MNETI encountered in India. The reported cases were observed in infants below one year of age. Males were affected more than the females. Except for one in the orbit, all the lesions were located in the maxilla. Histologically, lesions have been reported to be classical and benign in nature. Morphology of the tumours have been presented and discussed.
Role of magnetic field on transient forced and free-convection flow past an infinite vertical porous plate through porous medium with heat source
(Kluwer Academic Publishers, 1991) Basant Kumar Jha
Effects of magnetic field and permeability of the porous medium on unsteady forced and free-convection flow past an infinite vertical porous plate in presence of temperature-dependent heat source have been analysed. The Laplace transform method is used to obtain the expression for velocity field, skin friction, and leading edge effects. During the course of discussion, the effects of M (magnetic parameter), S (heat source parameter), λ (suction parameter), and K (permeability of porous medium) on velocity field, skin friction, and leading edge effect have been extensively discussed. © 1991 Kluwer Academic Publishers.
Strain analysis of deformed pebbly horizon from the Garhwal Group, Pharsaun, District Chamoli, UP
(1991) V.K. Gairola; D. Hatwal
A deformed pebbly horizon has been observed in the quartzitic phyllite member of the Garhwal Group rocks exposed along a ENE-WSW striking fault, south of village Pharsaun, District Chamoli, U.P. The strain analysis reveals that the mean shape of the pebbles prior to deformation, was flattening type and with progressive deformation, the shape of the pebbles changed to constriction type, then to flattening type, and finally to constriction type. The deformation of the pebbles has been related to the first tectonic movement. -from Authors
Electric field mapping of bipyridine cardiotonics: amrinone and milrinone
(1991) Anil Kumar; A.K. Bhattacharjee; P.C. Mishra
Electric field maps of amrinone and milrinone which are well known for their inotropic activity and vasodilatory properties have been studied using a point dipole as the mapping probe. Electrostatic potential maps of the molecules are also presented. The net charge distributions in the molecules have been obtained using the MNDO molecular orbital method. The results show a prominent electric field region in milrinone extending from near the oxygen atom to near the methyl group 2.0 A above the pyridine ring plane which, in terms of the Erhardt model, may be related to the greater cardiotonic activity of this molecule in comparison to that of amrinone. © 1991.
Phage P22 helps phage MB78 to overcome blockage of DNA maturation in rifampicin-resistant host
(1991) Saeed Ahmad Khan; Manzoor A. Zargar; Maharani Chakravorty
Bacteriophage MB78, a virulent phage of Salmonella typhimurium cannot grow in rifampicin-resistant mutant (rif-39) of the host having altered RNA polymerase. The temperate phage P22 which cannot multiply in presence of the virulent phage MB78 can, however, help MB78 to overcome replication inhibition in rif-39. The processing of concatemeric phage DNA to monomer is blocked in this nonpermissive host. Superinfection with P22 induces synthesis of at least five P22 specific polypeptides which help phage MB78 in the processing of the concatemeric DNA and maturation of phage particles. © 1991 Indian Academy of Sciences.
Total glycoside content and antistress activity of Indian and Mauritius Centella asiatica - A comparison [1]
(1991) S.C. Upadhyay; R.L. Khosa; D. Nandkuma Sharma; M. Kumar; J.P.N. Chansauria
[No abstract available]
Prevalence of skin diseases in Varanasi school children
(1991) A.R. Valia; S.S. Pandey; P. Kaur; G. Singh
[No abstract available]
Nutritional control of copper uptake in the cyanobacterium Nostoc calcicola Bréb
(Springer-Verlag, 1991) Sanjay Kumar Verma; S.P. Singh; R.K. Singh
The kinetics of Cu uptake in nutritionally starved cells of the diazotrophic cyanobacterium Nostoc calcicola Bréb. have been compared with those in cells recovering from starvation. Unstarved cyanobacterial cells assimilated 97.0 nmol Cu mg-1 protein within 1 h when incubated in medium containing 40 μM Cu. Uptake was markedly inhibited in carbon-starved cells and, to a lesser extent, in cells starved of nitrogen or sulphur. The intracellular concentrations of protein and photopigments were markedly lower in cells starved of carbon, nitrogen, sulphur or phosphorus, whilst that of carbohydrate was lower in cells starved of carbon, sulphur or phosphorus, but almost doubled in cells starved of nitrogen. The ability to assimilate Cu was partially restored in cells after 72 h of recovery from phosphorus or sulphur deprivation, but showed little improvement during recovery from carbon or nitrogen starvation. A possible role of phosphorus in regulating Cu transport and accumulation is discussed. © 1991 Springer-Verlag.
Inhibition of photosynthetic electron transport in nostoc muscorum by ni2+and Ag+
(1991) J.B. Singh; S.M. Prasad; L.C. Rai
This paper presents the inhibition of photosynthetic electron transport chain of Nostoc muscorum by divalent Ni2+ and monovalent Ag 4. PS I (DCPIP/ASC͢MV) and PS II (H2O͢PBQ) activities were markedly inhibited by Ni21 and Ag+ in a concentration-dependent fashion but PS II was more susceptible than PS I to Ni2+. Ag+ was more toxic to PS I than PS II. The greater sensitivity of PS II to Ni2+ was further confirmed by the inhibition of DCPIP photoreduction and Chl a fluorescence. Restoration of Ag+-induced inhibition of DCPIP photoreduction and Chl a fluorescence by artificial electron donors (DPC, NH2OH, MnCl2) and their failure to restore Ni2+-induced inhibition suggests that Ni2+ inactivates PS II by causing alteration and destruction of photosynthetic membranes, but Ag+ inhibits the electron flow at the oxidizing side of PS II. Nevertheless, the suppression of the fluorescence intensity at low concentrations of both metal cations points to the involvement of phycobilisomes in the inhibition of PS II activity. © 1991, Applied Microbiology, Molecular and Cellular Biosciences Research Foundation. All rights reserved.
Microstructural stability in a Cu-Cr-Si alloy under 300 keV Cu+ ion irradiation
(1991) C. Ramachandra; N. Wanderka; R.P. Wahi; H. Wollenberger
The stability of precipitate phases in a Cu-base alloy under irradiation with 300 KeV Cu+ ions has been investigated. The irradiations were carried out in the temperature range of 200°C to 530°C at displacement rates of 2.3 × 10-2 and 2.3 × 10-5 dpa/s, respectively. Of the two types of precipitates which form in this alloy under thermal ageing, the metastable. coherent precipitates of fcc chromium either do not form or dissolve, if already present, under most irradiation conditions. The second population of precipitates, i.e. incoherent particles of the stable phase Cr3Si, grow to a temperature dependent stable size under all irradiation conditions. The results are interpreted in terms of mechanisms of cascade mixing and radiation enhanced diffusional growth. © 1991.
Differential methylation of HMG proteins by dexamethasone in the liver of aging rats
(1991) S. Prasad; M.K. Thakur
In vitro methylation of HMG proteins was studied in young and old rats by incubating liver slices with (methyl-14C)methionine. The level of methylation of all the four HMG proteins was relatively higher in young, as compared to old rats. Dexamethasone stimulated the methylation of HMG 2 to 12-fold, and inhibited that of other HMGs in young rats. On the other hand, it stimulated all major HMG proteins except HMG 2, which remains unchanged in old age. Such differential methylation of HMG proteins induced by dexamethasone affects the structure and function of chromatin during aging. (Aging 3: 333-335,1991) © 1991, Editrice Kurtis s.r.l.. All rights reserved.
A revision of the Indian species of subgenus Scaptodrosophila (Diptera: Drosophilidae)
(1991) A.K. SUNDARAN; J.P. GUPTA
The subgenus Scaptodrosophila of the genus Drosophila from India is revised, with the description of six new species, D. elenthiensis sp.n., D. ovidenticulata sp.n., D. oviminiatus sp.n., D. paraclubata sp.n., D. paratriangulifer sp.n., D. peniquadrata sp.n., and a new distribution record of D. pressobrunnea Tsacas & Chassagnard. A key to Indian species of Scaptodrosophila is also provided. Copyright © 1991, Wiley Blackwell. All rights reserved
X–ray Diffraction Study on an Eight–coordinated Uranium (VI) Complex
(1991) I.S. Ahuja; Shailendra Tripathi
[No abstract available]
Faunal response to transgressive-regressive cycles: example from the Jurassic of western India
(1991) Franz T. Fürsich; Wolfgang Oschmann; Anand K. Jaitly; Indra Bir Singh
Upper Callovian to Oxfordian shelf sediments at Ler in the Kachchh Basin, western India, are interpreted in terms of transgressive-regressive cycles. The transgressive phases are represented by thin layers of reworked and bored concretions, sometimes in association with skeletal concentrations, the regressive phases are documented by much thicker units of largely fine-grained sediments. The benthic fauna of transgressive and regressive phases differes markedly and thus mirrors the sedimentary cycles: During transgressive phases non-sedimentation produced hard substrates colonized mainly by byssate, cemented, or pedicle-attached suspension-feeding epifaunal species, whilst sediment input during regressive phases lead to soft substrate conditions characterized by infaunal deposit- and suspension-feeders as well as by epifaunal opportunists. Whereas the composition of the "regressive fauna" remains fairly constant through time, that of successive "transgressive faunas" often differs drastically. This is possibly due to a greater environmental sensitivity of epifaunal taxa as compared to infaunal taxa. © 1991.