Showing papers by "University of Rajasthan published in 1999"

Phenylacetic acid improves bud elongation and in vitro plant regeneration efficiency in Capsicum annuum L.

Abstract: We have developed a highly efficient three-stage protocol for plant regeneration in sunflower (Helianthus annuus L.) from embryonal cotyledons. This protocol uses phenylacetic acid (PAA) for both shoot-bud induction and the elongation of smaller buds. The medium used for inducing bud formation from the cotyledons was modified MS medium supplemented with 3 mg/l 6-benzylaminopurine (BAP) and 0.5 mg/l PAA. Buds were elongated on MS medium supplemented either with only 0.2 mg/l gibberellic acid (GA3) or with 0.2 mg/l GA3 + 0.1 mg/l PAA + 0.3 mg/l BAP. The elongated shoots were then transferred onto rooting medium containing 1 mg/l PAA. The complete plantlets with well-developed roots were transferred to field conditions where they survived and set normal seeds. The induction of shoot buds from embryonal cotyledons was also observed on modified MS medium supplemented with 0.5–5 mg/l BAP in combination with 0.5–5 mg/l α-naphthaleneacetic acid (NAA). In this case, the formation of callus took place along with shoot-bud formation, which hindered further development of the latter. The presence of PAA with BAP in the primary bud induction medium promoted normal development and elongation of shoot buds.

Antifertility effect of aqueous extract of seeds of Cassia fistula in female rats.

Abstract: Oral administration of aqueous extract of seeds of Cassia fistula to mated female rats from day 1-5 of pregnancy at the doses of 100 and 200 mg/kg body weight resulted in 57.14% and 71.43% prevention of pregnancy, respectively, whereas 100% pregnancy inhibition was noted at 500 mg/kg bw. In the uterine bioassay test carried out in immature bilaterally ovariectomized female rats, aqueous extract of seeds of Cassia fistula (100 mg/kg bw) increased the uterine wet weight (p<0.05) and luminal epithelial cell height (p<0.001) but did not induce premature opening of the vagina. This suggests a mild estrogenic activity of the extract. However, when the extract was administered conjointly with estradiol valerate (EDV, 0.1 mg/kg bw), it significantly (p<0.001) prevented the estrogen-induced uterotrophic effect, thus showing an antiestrogenic nature of the extract in the presence of a strong estrogen.

Modulatory potential of Spirulina fusiformis on carcinogen metabolizing enzymes in Swiss albino mice

Abstract: The modulatory potential of Spirulina fusiformis was observed on the hepatic and extrahepatic carcinogen metabolizing enzymes in Swiss albino mice at a dose of 800 mg/kg b.w. given orally. A significant reduction in the hepatic cytochrome P-450 content was observed in the group treated with Spirulina in comparison with the control group. The hepatic glutathione S-transferase activity was induced significantly by Spirulina treatment. There was no change in the extrahepatic glutathione S-transferase activity after the animals were fed with Spirulina.

Organotin(IV) complexes of biologically active Schiff bases derived from heterocyclic ketones and sulpha drugs

Abstract: Some new hexa-coordinated organotin complexes [Bu2Sn(NN)2] (where NN is the anion of various Schiff bases) have been synthesized and characterized on the basis of elemental analysis, conductivity measurements, molecular weight determination, and ultraviolet, infrared and multinuclear magnetic resonance (1H, 13C and 119Sn) spectral studies. A few representative complexes have also been screened for their antibacterial and antifungal activity and found to be quite active in this respect. Copyright © 1999 John Wiley & Sons, Ltd.

Fragmentation and multifragmentation of 10.6A GeV gold nuclei

Abstract: The experimental data on the interactions of 10.6A GeV gold nuclei in nuclear emulsions are analyzed with particular emphasis of target separation interactions and study of critical exponents. Charged fragment moments, conditional moments as well as two and three – body asymmetries of the fast moving projectile particles are determined in terms of the total charge remaining bound in the multiply charged projectile fragments. Some differences in the average yields of helium nuclei and heavier fragments are observed, which may be attributed to a target effect. However, two and three-body asymmetries and conditional moments indicate that the breakup mechanism of the projectile seems to be independent of target mass. We looked for evidence of critical point observable in finite nuclei by study the resulting charged fragments distributions. We have obtained the values for the critical exponents γ, β and τ and compare our results with those at lower energy experiment (1.0A GeV data). The values suggest that a phase transition like behavior, is observed.

A preshower photon multiplicity detector for the WA98 experiment

Abstract: A high granularity preshower detector has been fabricated and installed in the WA98 Experiment at the CERN SPS for measuring the spatial distribution of photons produced in the forward region in lead-ion-induced interactions. Photons are counted by detecting the preshower signal in plastic scintillator pads placed behind a 3 radiation length thick lead converter and applying a threshold on the scintillator signal to reject the minimum ionizing particles. Techniques to improve the imaging of the fibre and performance of the detector in the high multiplicity environment of lead–lead collisions are described. Using Monte-Carlo simulation methods and test beam data of π− and e− at various energies the photon counting efficiency is estimated to be 68% for central and 73% for peripheral Pb+Pb collisions.

High-δ13C Paleoproterozoic Carbonates from the Aravalli Supergroup, Western India

Abstract: High δ13C values up to 11%PDB occur in Paleoproterozoic dolostones from the Aravalli Supergroup, western India. Correlation of high δ13C with high δ18O up to 23%SMOW in the studied carbonates suggests that pre-metamorphic δ13C values were above 10%PDB. The data are consistent with worldwide positive excursions in the δ13C of marine bicarbonate. The positive excursion was contemporaneous with sedimentation.

Modulation of lead toxicity by Spirulina fusiformis.

Abstract: The modulatory effects of lead toxicity by Spirulina fusiformis (Oscillatoreaceae) were observed on the testes of Swiss albino mice at a dose of 800 mg /kg body weight. The Spirulina fusiformis was non-toxic at the dose given. A significant enhancement in the survival time was observed in the pre- and post- treated Spirulina group compared with the control (lead treated) group. Lead induced toxicity was also reduced in terms of testes weight, animal weight, tubular diameter in the pre Spirulina treated group. The modulatory effects of Spirulina may be attributed to the presence of the antioxidants, β-carotene and SOD enzyme. Copyright © 1999 John Wiley & Sons, Ltd.

Reversible azoospermia by oral administration of the benzene chromatographic fraction of the chloroform extract of the seeds of Carica papaya in rabbits.

Abstract: Contraceptive efficacy, reversibility and toxicity, if any, of the benzene, chloroform and ethyl acetate chromatographic fractions of the chloroform extract of the seeds of Carica papaya have been investigated in adult male rabbits at a dose regimen of 50 mg/animal/day for 150 days of treatment. Body weight, semen analysis, hematology, serum clinical biochemistry and the fertility status of control and treated animals were evaluated. Chloroform and ethyl acetate chromatographic fractions did not produce appreciable changes in these parameters. However, the benzene chromatographic fraction resulted in uniform azoospermia after 15 days of treatment, which was maintained for the remainder of the 150-day observation period. The levels of fructose, glycerophosphocholine, acid phosphatase and lactate dehydrogenase in the seminal plasma were within the control range. Hematology and the serum clinical parameters showed no appreciable changes, indicating lack of toxicity. The libido of the treated animals was normal and the fertility rate was zero. Complete normalcy of altered parameters was observed 60 days following withdrawal of treatment. It is concluded that the benzene chromatographic fraction of the chloroform extract of the seeds of Carica papaya possesses reversible male contraceptive potential and the effects appear to be mediated through the testis.

Cytokinins in pathogenesis and disease resistance of Pyrenophora teres-barley and Dreschslera maydis-maize interactions during early stages of infection.

Abstract: Infection of Hordeum vulgare L. by Pyrenophora teresand of Zea mays by Dreschslera maydis were characterized by ‘green island’ formation, higher cytokinin levels and accumulation of metabolites in the infected areas. Higher cytokinin concentrations of the order 6-Y,Y-dimethylallylaminopurine > zeatinriboside > zeatin >dihydrozeatinriboside were detected at infection sites of susceptible hosts. By virtue of these cytokinins, infection sites may be acting as metabolic sinks helping proliferation of the pathogen. Existence of translocatory sinks at infection zones was confirmed from autoradiographic studies,where, accumulation of labeled metabolites was prominent at infection sites of susceptible hosts. Upon infection the lower cytokinin levels of resistant hosts decreased further with progress of infection. In the infected resistant hosts the concentrations of zeatin/zeatinriboside were the maximum among the four identified cytokinins. The pathogen is also capable of secreting cytokinins as evident from quantification of cytokinins in culture filtrate extracts using HPLC. Since detached leaves were used in the experiments the increase/decrease of various cytokinin levels may be attributed to pathogen influence. The increase in cytokinin levels in the susceptible host may be aiding the growth of the pathogen on one hand, while the decrease in the infected resistant host may signal the host to activate defenses against a potential pathogen at the early stage of infection.

Geochemical Discrimination Diagrams: A Simple Way of Replacing Eye-Fitted Field Boundaries With, Probability Based Classifier Surfaces

Abstract: The subjective, eye-fitted, field boundaries in geochemical discrimination diagrams constitute one of the possible reasons for their often-noted inability to determine the source regime/tectonic environments of igneous rocks. A simple method is described here to replace the eye-fitted field boundaries between the groups with the probability based classifier surfaces. It involves projection of the assignment rules obtained from linear discriminant analysis onto the binary or ternary discrimination diagram of raw variables. The method is illustrated by obtaining classifier surface between I- and S-type granites in Na 2 O-K 2 O space and between Anorthosite/Rapakivi (AR) and Ring Complex (RC) granites in Na 2 O-MgO space. The need for explicitly ensuring adequacy of samples, selection of suitable variables, evaluation of rate of misclassification and a better understanding of the unique influence of tectonic environments on magmatic process is emphasized for optimizing the performance of the classifier surface.

Electronic structure, Fermi surface, and Curie temperature calculations for the Co-Pt system

Abstract: Three ordered compounds of the Co-Pt system, namely ${\mathrm{Co}}_{3}\mathrm{Pt},$ CoPt, and ${\mathrm{CoPt}}_{3},$ are ferromagnetic in nature. We have performed band-structure calculations for these compounds using the ab initio linear muffin-tin orbitals method. Our results are in agreement with the experimentally measured ground-state properties such as density of states, electronic specific-heat coefficient, and magnetic moments. The band-structure results along with the Mohn Wohlfarth theory are used to calculate the Curie temperature of these compounds. Our calculated values of the Curie temperature are in agreement with the experimental data of the Curie temperature. We also report calculations for the Fermi surface of ${\mathrm{Co}}_{3}\mathrm{Pt}$ and ${\mathrm{CoPt}}_{3}$ with the aim to ascertain how the Fermi surface is altered when Co(Pt) is replaced by Pt(Co), keeping the same crystal structure.

Trondhjemite and Granodiorite Assemblages from West of Barmer: Probable Basement for Malani Magmatism in Western India

Abstract: The pre-Malani basement, occurring to the southwest of the Malani Igneous Suite in western India is represented by an older, biotite trondhjemite (gneiss) and a younger, hornblende granodiorite. These granitoid assemblages (hitherto mentioned as unclassified granitoids) denote tectonically uplifted basement for the volcano-plutonic Malani magmatism. Biotite trondhjemite with well-developed gneissic fabric is significantly deformed as compared to hornblende granodiorite, which is slightly deformed. The basement granitoids exhibit a well-defined temporal and spatial relationship with each other, and are further intruded by Malani rhyolite/basic dykes. Well-preserved magmatic fabric of rhyolite/basic dykes suggests that the intrusive activity post-dated any deforrnational event. The geochemical signatures of the basement granitoids - moderate silica, high Sr, low FeO/MgO ratio and moderate alkali abundance, are quite distinct from the A-type geochemistry of Malani rhyolite dykes - high silica, high HFSE abundance, high FeO/MgO ratio and high alkali abundance, thus invoking different sources and emplacement history.

Superconducting Properties of Metallic Glass Ca70Mg30through Ashcroft's Pseudopotential

Abstract: The screened form factors obtained from the Ashcroft's empty core model pseudopotential for electron-ion interaction by employing Geldart and Vosko screening have been used for the prediction of the superconducting state properties viz. electron-phonon coupling strength λ, Coulomb pseudopotential μ * , transition temperature T c , isotope effect exponent α, and the interaction strength N 0 V of binary metallic glass Ca 70 Mg 30 . The results obtained are in the expected range. The obtained T c value of 17 K suggests suitability of this metallic glass for its use as lossless transmission line for cryogenic applications.

Reversible antispermatogenic effect of gossypol in langur monkeys (Presbytis entellus entellus).

Abstract: The present investigation reports the antispermatogenic effect of the orally active highly purified gossypol acetic acid at 7.5 mg and 10 mg/day for 180 days in langur monkeys. The results revealed a dose-dependent response in semen analysis as well as testicular morphology. Uniform severe oligospermia was observed in the lower dose (7.5 mg) group, while azoospermia was observed in 2 out of 5 animals in the higher dose (10 mg) group and the remaining animals showed severe oligospermia. Scanning electron microscopy of spermatozoa revealed deleterious abnormalities in the head and midpiece. Testicular morphology revealed a decrease in the seminiferous tubule diameter and arrest of spermatogenesis. The lower dose group had a germ cell population up to primary spermatocytes while the higher dose group had only Sertoli cells and spermatogonia. Withdrawal of treatment for 180 days led to the recovery of all the parameters studied, to normalcy.

Chemopreventive action by an extract from Brassica compestris (var Sarason) on 7,12-dimethylbenz(a)anthracene induced skin papillomagenesis in mice.

Abstract: We report the chemopreventive property of an ethanolic extract of the seeds of Brassica compestris var sarason (mustard seed) on DMBA (7,12 dimethylbenz(a)anthracene induced skin papillomagenesis in male Swiss albino mice. A significant reduction in the values of tumour incidence, tumour burden and the cumulative number of papillomas was observed in mice treated orally with the seed extract of Brassica compestris var sarason, continuously at peri and post initiational stages of papillomagenesis compared with the control groups. The latency period in the experimental group significantly increased (11.3 ± 0.40 weeks) compared with the control group (7.8 ± 0.17). Copyright © 1999 John Wiley & Sons, Ltd.

Meso-Ionic Heterocycles

Abstract: The term meso-ionic (mesomeric + ionic) was first introduced by Baker and Ollis1,2 in 1949 to describe the structure of N-phenylsydnone 1 as a resonance hybrid of the dipolar resonating structures (i—iii) (Fig. 1).

Synthesis and Characterization of Some Tin(II) Complexes with Semicarbazones and Thiosemicarbazones of Heterocyclic Ketones

Abstract: Synthesis and characterization of tetracoordinated tin(II) complexes with semicarbazones and thiosemicarbazones of heterocyclic ketones viz 2-acetylpyridine, 3-acetylpyridine, 2-acetylnaphthalene, 2-acetyfuran and 2-acetylthiophene in 1:1 stoichiometry are reported The conductance measurements in DMF show these complexes to be non-electrolytes and the molecular weight determinations indicate their monomeric nature The nature of bonding is discussed on the basis of the electronic, infrared, multinuclear magnetic resonance (1IT, 13C,and 119Sri) and 119Sn Mossbauer spectral studies