Showing papers by "North Eastern Hill University published in 2003"

Vascular plant diversity in the sacred groves of Jaintia Hills in northeast India

Abstract: Diversity of vascular plants was studied in three sacred groves of the Jaintia Hills, in northeast India. About 395 species, 250 genera, and 108 families comprising pteridophytes, gymnosperms and angiosperms were found in the groves. Orchidaceae, Rubiaceae, Asteraceae and Lauraceae were dominant families and Ficus was the largest genus, with nine species. About 160 tree species were distributed in canopy, subcanopy and under canopy strata of the forest. Concentration of tropical and temperate elements of the neighbouring Sino-Himalayan and Burma-Malayan regions, and endemic (54 species), rare (31 species) and primitive taxa (38 species) due to favourable climatic conditions and prolonged protection have contributed to the high species richness of the groves. Their better management and protection is important for the conservation of plant diversity in the region and also for the benefit of indigenous tribes of the state.

Ecosystem Restoration of Jhum Fallows in Northeast India: Microbial C and N Along Altitudinal and Successional Gradients

Abstract: To characterize the altitudinal and successional trends in microbial biomass and to understand their role in soil nutrient dynamics during the aggradation phase (vegetation recovery) of abandoned shifting cultivation systems, we determined the soil properties and microbial C and N in jhum (slash-and-burn) cultivation systems at different altitudes and 1-, 7-, and 16-year-old fallow agricultural lands at lower and higher altitudes in the northeastern Indian hills. Density of ground vegetation was lower in the undisturbed forest than in the jhum fallows. In general, 1-year jhum fallow had greater herbaceous vegetation both at lower and higher altitudes. Although woody plants were observed in 7- and 16-year-old jhum fallows, their density was highest in the forest. Soil moisture, organic C, and total N also increased gradually with increasing altitude and progressive secondary succession. Soil pH showed a negative correlation with altitude (as also confounded by soil type) and fallow age. Both microbial C and N had a close correlation with altitude and fallow age. Contribution of microbial C to soil organic C was 2.0-2.6% and microbial N to total N 1.4-2.2% in jhum fields, 2.4-4.3% and 1.2-2.1%, respectively, in jhum fallows, and 2.5-2.9% and 1.6-1.9% in the forests. Microbial C and N showed a negative correlation with herbaceous plant density. Microbial biomass in the jhum fallows and forest stands had a positive relationship with woody vegetation. Along an altitudinal and/or successional gradient, microbial C and N were positively correlated with water-holding capacity, soil moisture, organic C, and total N and negatively correlated with soil pH. Microbial C and N were positively correlated with each other. Therefore, the study suggests that the altitudinal and successional dynamics of microbial C and N are linked to, among other properties, soil organic matter and total nitrogen contents in the soil during community development after land abandonment from shifting cultivation.

Genotoxic effect of raw betel-nut extract in relation to endogenous glutathione levels and its mechanism of action in mammalian cells.

Abstract: The mutagenic and carcinogenic potency of betel-nut components is well established. This study was undertaken to determine the genotoxic potency of an aqueous extract of raw betel nut (AEBN) in relation to the endogenous glutathione (GSH) level in mouse bone marrow cells (BMC) and human peripheral blood lymphocytes (PBLs), and to find out whether arecoline (ARC), an alkaloid of betel nut, could generate reactive oxygen species (ROS) in these cells. It was observed that AEBN has genotoxic properties, which is further enhanced by depletion of endogenous GSH levels. However, the degree of enhancement varies with the type of parameter and cell system studied. The present data indicate that the generation of ROS by ARC could partially contribute to the induction of chromosomal aberrations (CAs), since the frequency of ARC-induced CAs was reduced either by post-treatment with superoxide dismutase (SOD) or in anoxic conditions. However, the induction of sister chromatid exchanges (SCEs) probably involves p53-dependent changes in cell proliferation and allowing some repair of DNA damage. The extent of damage for each parameter was higher when the mice were exposed to AEBN for 30 days than 5 days. Longer exposure showed higher level of p53 expression in mouse BMC, which could block the damaged cells from proliferation and allow the cells to repair the DNA damage.

Changes in endogenous tissue glutathione level in relation to murine ascites tumor growth and the anticancer activity of cisplatin

Abstract: Changes in glutathione levels were determined in tissues of 11- to 12-week-old Swiss albino mice at different stages of Dalton's lymphoma tumor growth and following cisplatin (8 mg/kg body weight, ip) treatment for 24-96 h, keeping 4-5 animals in each experimental group Glutathione levels increased in spleen of tumor-bearing compared to normal mice (995 +/- 014 vs 786 +/- 164 micromol/g wet weight, P

Quantum coherence of biophotons and living systems.

Abstract: Coherence is a property of the description of the system in the classical framework in which the subunits of a system act in a cooperative manner. Coherence becomes classical if the agent causing cooperation is discernible otherwise it is quantum coherence. Both stimulated and spontaneous biophoton signals show properties that can be attributed to the cooperative actions of many photon-emitting units. But the agents responsible for the cooperative actions of units have not been discovered so far. The stimulated signal decays with non-exponential character. It is system and situation specific and sensitive to many physiological and environmental factors. Its measurable holistic parameters are strength, shape, relative strengths of spectral components, and excitation curve. The spontaneous signal is non-decaying with the probabilities of detecting various number of photons to be neither normal nor Poisson. The detected probabilities in a signal of Parmelia tinctorum match with probabilities expected in a squeezed state of photons. It is speculated that an in vivo nucleic acid molecule is an assembly of intermittent quantum patches that emit biophoton in quantum transitions. The distributions of quantum patches and their lifetimes determine the holistic features of biophoton signals, so that the coherence of biophotons is merely a manifestation of the coherence of living systems.

Cisplatin-induced genotoxic effects and endogenous glutathione levels in mice bearing ascites Dalton's lymphoma.

Abstract: cis-Diaminedichloroplatinum(II), commonly known as cisplatin, treatment of mice for 24-96, 30 h and 10 days caused the development of chromosomal aberrations in bone marrow cells as well as in Dalton's lymphoma (DL) cells, micronuclei (MN) in bone marrow cells and abnormalities in sperm heads, and it indicates the genotoxic potential of cisplatin in the host. Cisplatin exerts differential effects on the chromosomes of the bone marrow and tumor cells. Combination treatment of cisplatin with L-buthionine(S,R)-sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, enhanced these cisplatin-induced genotoxic effects, but supplementing glutathione level with cysteine, its precursor, reduced the cisplatin-induced genotoxicity. The reduction in cellular glutathione level may facilitate increased intracellular accumulation and binding of drug to DNA to enhance the frequency of genotoxicity parameters. These findings support the possible involvement of glutathione as an important intracellular protective agent and suggest that differences in its levels may be one of the factors in the varying sensitivity of cells to cisplatin-induced genotoxic effects in the mice bearing ascites Dalton's lymphoma.

Synthesis and characterization of some dibutylbis{5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoato}tin(IV) compounds. Toxicity studies of di- and tri-organotin complexes on the second instar of Aedes aegypti mosquito larvae

Abstract: The preparation and spectroscopic characterization of some complexes of the type Bu2Sn(LH)2 (LH = 5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoate) are reported. On the basis of spectroscopic evidence (1H, 13C, 119Sn NMR, IR and 119mSn Mossbauer) the compounds were judged to adopt the usual dicarboxylato structural type with a skew trapezoidal arrangement. This was further confirmed by X-ray crystallography in the case of Bu2Sn(L5H)2 (L5H = 5-[(E)-2-(4-chlorophenyl)-1-diazenyl]-2-hydroxybenzoate). Toxicity studies of the di- and tri-organotin compounds on the second larval instar of Aedes aegypti mosquito larvae are reported. Copyright © 2003 John Wiley & Sons, Ltd.

Growth and nutritional status of Khasi boys in northeast India relating to exogamous marriages and socioeconomic classes.

Abstract: The Khasis are one of the matrilineal tribes of Meghalaya in Northeast India. They belong to the Indo-Mongoloid racial stock and speak the Monkhmer language of the Austro-Asiatic group. They have their own traditional religion (Niam Khasi) but about 65% of them have converted to Christianity. A few Khasi members have also embraced Islam through matrimonial relationship with immigrant Muslim males. The present study was based on a cross-sectional sample of 1351 urban Khasi boys aged 3-18 years belonging to these three religious groups with a view to understanding the effects of socioeconomic factors on growth and nutritional status using anthropometric variables such as weight and height. The findings showed that about 60% 29% and 6% of these boys were below -2 Z- scores of the US National Center for Health Statistics (NCHS) references in respect of height for age weight for age and body mass index for age respectively. The logistic regression coefficient (s ± standard error) indicated that the prevalence of low weight for age (below -2 Z-scores of the NCHS references) was positively associated with age (0.088 ± 0.014 P 0.05). There were also significant differences between religious groups in respect of anthropometric variables. Allowing for household income the ANCOVA test indicated that Muslim Khasi boys who were the offspring of intermarriages between Khasi females and immigrant Muslim males were significantly heavier and taller than Christian and Niam Khasi boys almost across ages. From about 3-10 years of age Muslim Khasi boys were on average comparable to the 5th and 25th percentiles of the NCHS references of height and weight respectively. Although it looks as though genetic mechanisms like heterosis and/or gene flow might also be associated with the larger body size in Muslim boys such a conjecture could only be substantiated or refuted by further studies concerning genetic and more socioeconomic data on both immigrant and nonimmigrant populations. (authors)

Role of ureogenesis in tackling problems of ammonia toxicity during exposure to higher ambient ammonia in the air-breathing walking catfish Clarias batrachus.

Abstract: In the present study, the possible role of ureogenesis to avoid the accumulation of toxic ammonia to a lethal level under hyper-ammonia stress was tested in the air-breathing walking catfish Clarias batrachus by exposing the fish at 25 mM NH4Cl for 7 days. Excretion of ammonia by the NH4Cl-exposed fish was totally suppressed, which was accompanied by significant accumulation of ammonia in different body tissues. The walking catfish, which is otherwise predominantly ammoniotelic, turned totally towards ureotelism from ammoniotelism with a 5- to 6-fold increase of urea-N excretion during exposure to higher ambient ammonia. Stimulation of ureogenesis was accompanied with significant increase of some of the key urea cycle enzymes such as carbamyl phosphate synthetase (urea cycle-related), argininosuccinate synthetase and argininosuccinate lyase both in hepatic and non-hepatic tissues. Due to this unique physiological strategy of turning towards ureotelism from ammoniotelism via the induced urea cycle, this air-breathing catfish is able to survive in very high ambient ammonia, which they face in certain seasons of the year in the natural habitat.

Organotin(IV) complexes of N‐[(2Z)‐3‐hydroxy‐1‐methyl‐2‐butenylidene]glycine

Abstract: Organotin(IV) derivatives of N-[(2Z)-3-hydroxy-1-methyl-2-butenylidene]glycine have been synthesized and characterized by 1H, 13C, 119Sn NMR, 119Sn Mossbauer, and IR spectroscopy along with elemental analyses The di- and triorganotin(IV) complexes were readily obtained from the reactions of organotin halides and sodium/potassium N-[(2Z)-3-hydroxy-1-methyl-2-butenylidene]glycinate The diorganotin compound reacted with Ph3SnCl in refluxing benzene to give the mixed organotin dinuclear complex of composition Ph2Sn(2-OC(CH3)-C(H)C(CH3)NCH2COO)·Ph3SnCl, which was characterized by single crystal X-ray structure determination © 2003 Wiley Periodicals, Inc Heteroatom Chem 14:149–154, 2003; Published online in Wiley InterScience (wwwintersciencewileycom) DOI 101002/hc10116

Effects of heterosis on growth in height and its segments: a cross-sectional study of the Khasi girls in Northeast India.

Abstract: Background: It is generally believed that improvement in environmental quality is the main factor responsible for the better growth and nutritional status of children in developing countries. However, it is still not clear whether this better growth performance is also associated with heterosis and/or gene flow that may take place as a result of the geographical movement of individuals, or migration. Aim: The present paper attempts to examine the effects of heterosis on physical growth of girls in height and its segments. Subjects and methods: A cross-sectional sample of the Khasi girls of Shillong in Northeast India was considered in the present analysis. The height and sitting height of 1368 girls aged 3-18 years were measured with a Harpenden anthropometer, following standard techniques. The sample was divided into two groups, namely hybrid (HB) and non-hybrid (NHB) girls, in order to test the effects of heterosis using analysis of covariance with the household income as a covariate. The Preece-Baines ...

Estimation of micellization parameters of sodium dodecyl sulfate in water+1-butanol using the mixed electrolyte model for molar conductance.

Abstract: The mixed electrolyte model of Shanks and Franses has been applied to estimate the critical micelle concentration, aggregation number, and counterion binding constant of sodium dodecyl sulfate in a water + 1-butanol medium from its measured conductivity data at 25 °C. The surface potential of the ionic micelle in this mixed solvent medium was computed by solving the nonlinear Poisson–Boltzmann equation. The standard free energy terms of micellization were also calculated. The present study confirms further the observation made in the previous studies that ionic micelles do not contribute to the ionic strength of a surfactant solution, an inference originally made by McBain and coworkers.

Synthesis, Characterization and Molecular Structure of a new (?6-P-Cymene) Ruthenium(II) Amidine Complex, [(?6-P-Cymene)Ru{NH=C(Me)3,5-Dmpz}(3,5-Hdmpz)](BF4)2·H2O

Abstract: A new arene ruthenium(II) complex [(η6-p-cymene)Ru(L)(3,5-Hdmpz)](BF4)2[sdot]H2O (L = 1-methylcarbaldimino-3,5-dimethylpyrazole; 3,5-Hdmpz = 3,5-dimethylpyrazole) has been synthesized. The ligand L has been generated in situ through the condensation of 3,5-dimethylpyrazole and acetonitrile in the presence of [{(η6-p-cymene)RuCl2}2]. The complex [(η6-p-cymene)Ru{NH=C(Me)3,5-dmpz}(3,5-Hdmpz)](BF4)2[sdot]H2O crystallizes in monoclinic space group P21/c, a = 10.943(2), b = 26.394(7), c = 11.502(1) A, Β = 115.43(1)°, V = 3000.1(19) A3 and Z = 4. The compound has been characterized by FTIR, 1H NMR, 2D-COSY NMR spectroscopy and a single-crystal X-ray diffraction study.

Precision and uncertainties in mass scale predictions in SUSY SO(10) with \(SU(2)_{L}\times SU(2)_{R}\times U(1)_{B-L}\times SU(3)_C\) intermediate breaking

Abstract: In a class of SUSY SO(10) with $SU(2)_L\times SU(2)_R\times U(1)_{B-L}\times SU(3)_C (g_{2L} eq g_{2R})$ intermediate gauge symmetry, we observe that the prediction on the unification mass (M U ) is unaffected by Planck-scale-induced gravitational and intermediate-scale threshold effects, although the intermediate scale (M I ) itself is subject to such corrections. In particular, without invoking the presence of additional lighter scalar degrees of freedom but including plausible and reasonable threshold effects, we find that interesting solutions for neutrino physics corresponding to $M_{I}\simeq 10^{10}$ -1013 GeV and $M_{U}\simeq(5$ - $6)\times10^{17}$ GeV are permitted in the minimal models. The possibilities of low-mass right-handed gauge bosons corresponding to $M_{I}\simeq 1$ -10 TeV consistent with the CERN-LEP data are pointed out in a number of models in which threshold effects are included using effective mass parameters.

A British response to some Indian English usages

Abstract: English has been established in India for well over two centuries, and is now both its major lingua franca and ‘window on the world’. Some Indianisms are however little known beyond South Asia and are liable to be regarded by native speakers of English as ‘deviant’ in various ways. Here, a project is described in which a set of distinctive and representative Indian English expressions was shown to a group of native English speakers who were asked to comment on them. The list includes both distinctive words (such as face-cut, freeship, and weightage) and distinctive senses of universally used words (such as chaste, see, and tempo). The responses are discussed and a summarizing conclusion presented.

Syntheses of [(η 6- p -cymene)Ru(EPh3)2Cl]+ complexes and molecular structure of chloro(η 6- p -cymene)-bis(triphenylphosphine)ruthenium(II) tetrafluoroborate (E = P, As and Sb)

Abstract: The reaction of [(η6-p-cymene)RuCl2]2 with excess EPh3 (E = P, As, Sb) in methanol in the presence of ammonium tetrafluoroborate leads to the formation of complexes of the type [(η6-p-cymene)Ru(EPh3)2Cl]BF4, E = P (1), As (2), Sb (3), which arise through cleavage of the chloride bridges. These complexes were characterized by spectral and analytical data. The crystal structure of 1 was solved by single-crystal X-ray crystallography in order to establish the exact structure in the solid state. The complex crystallizes in monoclinic space group P21/n (#14) with a = 12.42500(10), b = 30.1925(3), c = 11.06530(10) A, β = 103.1470(10)°.

Electrical Conductance Behavior of Oil-in-Water Microemulsions Stabilized by Sodium Dodecyl Sulfate and 1-Butanol

Abstract: The specific conductivity of several oil-in-water (o/w) microemulsions (MEs) stabilized by sodium dodecyl sulfate and 1-butanol was measured at 25 °C as functions of the volume fraction of oil (φ0) and the molar ratio of water to surfactant (R). The oils used are octane, benzene, toluene, carbon tetrachloride, chloroform, cyclohexane, xylene, and nitrobenzene. The conductivity data were explained by the modified Bruggeman equation in the entire experimental range of φ0 in the case of octane and nitrobenzene and in a limited range of φ0 in the case of other oils. The value of the slope of this equation, f, is found to depend on (i) the concentration of surfactant or the R value, (ii) the nature of the oil, and (iii) the nature and number of substituents, if the oil is a substituted benzene. The specific conductivity data of o/w MEs of R = 120 and 100 were also analyzed in the light of the mixed electrolyte model, and the values of aggregation number, counterion binding constant, and radius of droplet were ...