Showing papers by "North Eastern Hill University published in 2001"

New formulas and predictions for running fermion masses at higher scales in SM, 2HDM, and MSSM

Abstract: Including contributions of scale-dependent vacuum expectation values, we derive new analytic formulas and obtain substantially different numerical predictions for the running masses of quarks and charged leptons at higher scales in the SM, 2HDM and MSSM. These formulas exhibit significantly different behaviours with respect to their dependence on gauge and Yukawa couplings from those derived earlier. At one-loop level, the masses of the first two generations are found to be independent of the Yukawa couplings of the third generation in all three effective theories in the small mixing limit. Analytic formulas are also obtained for the running of $\tan\beta(\mu)$ in 2HDM and MSSM. Other numerical analyses include a study of the third generation masses at high scales as functions of the low-energy values of $\tan\beta$ and the SUSY scale $M_{\mathrm{S}}=M_Z-10^4$ GeV.

Characterization of Human FSH Isoforms Reveals a Nonglycosylatedβ -Subunit in Addition to the Conventional Glycosylatedβ -Subunit

Abstract: Human FSH consists of a mixture of isoforms that can be separated on the basis of differences in negative charge conferred by variations in the numbers of sialic acid residues that terminate oligosaccharide branches. Western analysis of human FSH isoforms separated by chromatofocusing revealed the presence of two human FSHβ isoforms that differed in size. A low mol wt human FSHβ isoform was associated with all FSH isoform fractions. A high mol wt human FSHβ isoform was associated with the more acidic fractions and increased in relative abundance as the pI decreased. Characterization of representative human FSHβ isoforms by mass spectrometry and automated Edman degradation revealed a low mol wt isoform that was not glycosylated. A high mol wt isoform was N-glycosylated at Asn residues 7 and 24. These results indicate that pituitary human FSH consists of two classes of molecules: those that possess a nonglycosylated β-subunit and those that possess a glycosylated β-subunit. Glycoprotein hormones are known t...

Body mass index of adult males in 12 populations of northeast India.

Abstract: Background: Of the anthropometric indices, body mass index (BMI) is considered to be more nutritionally than genetically related. Thus, in a country with diverse ethnic groups like India, it is more appropriate to use BMI as an indicator of the nutritional status of adult population. However, literature on BMI of adult Indians is limited to certain geographical regions or populations, and little is known about the populations in the northeast region of the Indian sub-continent.Aim: The present report deals with the BMI of adult males in 12 populations of Northeast India with a view to understanding their nutritional status.Subjects and methods: Anthropometric data collected by the Anthropological Survey of India on 946 adult males aged 18-62 years of 12 populations in Northeast India were used in this analysis. The populations were broadly categorized into three groups, namely, caste, Hinduized and tribal groups. The data were collected mostly from rural areas, taking into consideration the different soci...

Vertical distribution and seasonal changes of fine and coarse root mass in Pinus kesiya Royle Ex.Gordon forest of three different ages

Abstract: Seasonal changes and vertical distribution of fine ( Pinus kesiya and fine root and rhizome mass of herbaceous species, and root production were studied in the 6-, 15- and 23-year old Pinus kesiya forest stands at Shillong, in the Meghalaya state of north-east India. Maximum fine and coarse root mass of P. kesiya, and fine root and rhizome mass of the ground vegetation were recorded during the rainy season. The contribution of the tree fine roots in 0-10 cm soil layer declined from 51% in the 6-year old stand to about 33% in the older stands. The major proportion (63-88%) of herbaceous fine root and rhizome mass was concentrated in this soil layer in all the three stands. The majority (36-57%) of tree coarse roots were present in the 10-20 cm layer in all the stands. The biomass and necromass values in the case of fine roots were more or less equal in a given stand, but the coarse roots had 5 to 9 times more live than the dead mass. The proportion of herbaceous fine root mass to the total fine root mass declined from 54% in the 6-year old stand to 30-32% in the 15- and 23-year old stands. The mean total fine root mass (pine + herbaceous species) decreased from 417 g m –2 in the 6-year old stand to 302 in 15-year and 322 g m –2 in the 23-year old stand. Annual fine root production showed a marked decrease from 1055 g m –2 in the 6-year old stand to 743 g m –2 in the 23-year old stand, but coarse root production increased from 169 g m –2 in the 6-year to 466 g m –2 in the 23-year old stand; the total root production thus remained approximately constant.

Synthesis, characterization of diorganotin(IV) complexes of N-(2-hydroxyarylidene)amino-acetic acid and antitumour screening in vivo in Ehrlich ascites carcinoma cells

Abstract: Some new diorganotin(IV) complexes have­been prepared by reacting potassium N-(2-hydroxyarylidene)aminoacetate with R2SnCl2(R =­Me,nBu,Ph). The complexes have been characterized by 1H,13C,119Sn NMR, IR and 119mSn Mossbauer spectroscopic techniques in combination with elemental analysis. In the solid state, the complexes possess penta- and hexa-coordinated tin centres. The hexa-coordinated tin complexes were found to dissociate in solution, giving rise to penta-coordinated species­as revealed by 119Sn NMR spectroscopy. Antitumour screening in vivo of the complexes L4SnPh2,L4SnPh2·Ph3SnCl and L4SntBu2·t Bu2SnCl2 (L4 = N-(2-hydroxyacetophenone)aminoacetate) is also reported. Copyright © 2001 John Wiley & Sons, Ltd.

Occupational Structure and Incidence of Poverty in Indian Towns of Different Sizes

Abstract: This paper investigates the incidence of poverty in Indian towns and cities of various sizes of population. It also tests the hypothesis that larger towns and cities, because of their size, are capable of supporting more complex economic activities, improving labor productivity, and hence lowering the incidence of poverty. In particular, similar levels of education, ceteris paribus, have a larger impact in bigger conurbations.

Large neutrino mixing from renormalization group evolution

Abstract: The renormalization group evolution equation for two neutrino mixing is known to exhibit a nontrivial ``fixed point'' structure corresponding to maximal mixing at the weak scale. Their presence provides a natural explanation of the observed maximal mixing of ${\ensuremath{ u}}_{\ensuremath{\mu}}\ensuremath{-}{\ensuremath{ u}}_{\ensuremath{\tau}}$ if the ${\ensuremath{ u}}_{\ensuremath{\mu}}$ and ${\ensuremath{ u}}_{\ensuremath{\tau}}$ are assumed to be quasidegenerate at the seesaw scale without constraining the mixing angles at that scale. In particular, it allows them to be similar to the quark mixings as in generic grand unified theories. We discuss implementation of this program in the case of the minimal supersymmetric standard model and find that the predicted mixing remains stable and close to its maximal value, for all energies below the O (TeV) SUSY scale. We also discuss how a particular realization of this idea can be tested in neutrinoless double beta decay experiments.

Role of ureogenesis in the mud-dwelled Singhi catfish (Heteropneustes fossilis) under condition of water shortage.

Abstract: The air-breathing Singhi catfish Heteropneustes fossilis was kept inside moist peat for 1 month mimicking their normal habitat in summer and the role of ureogenesis for their survival in a water-restricted condition was studied. The ammonia excretion rate by the mud-dwelled fish increased transiently between 6 and 12 h of re-immersion in water to approximately between eight and 10-fold, followed by a sharp decrease almost to the normal level at the later part of re-immersion. The urea-N excretion by the mud-dwelled fish increased to approximately 11-fold within 0-3 h of re-immersion, followed by a gradual decrease from 9 h onwards. The rate of urea-N excretion by the mud-dwelled fish, however, remained significantly higher (approx. threefold more) than the control fish even after 36-48 h of re-immersion. Although there was a significant increase of both ammonia and urea levels in the plasma and other tissues (except ammonia in the brain), the level of accumulation of urea was higher than ammonia in the mud-dwelled fish as indicated by the decrease in the ratio of ammonia: urea level in different tissues including the plasma. The activities (units/g tissue and /mg protein) of glutamine synthetase and three enzymes of the urea cycle, carbamyl phosphate synthetase, argininosuccinate synthetase and argininosuccinate lyase increased significantly in most of the tissues (except the brain) of the mud-dwelled fish as compared to the control fish. Higher accumulation of ammonia in vivo in the mud-dwelled Singhi catfish is suggested to be one of the major factors contributing to stimulation of ureogenesis. Due to this physiological adaptive strategy of ureogenesis, possibly along with other physiological adaptation(s), this air-breathing amphibious Singhi catfish is able to survive inside the moist peat for months in a water-restricted condition.

Hematotoxicity and blood glutathione levels after cisplatin treatment of tumor-bearing mice.

Abstract: The involvement of glutathione, a major cellular antioxidant, in cisplatin-mediated development of various hematological changes in mice bearing ascites Dalton lymphoma tumor was investigated With tumor growth, glutathione levels decreased in blood but increased in tumor cells Cisplatin treatment of tumor-bearing mice caused a decrease in glutathione levels in blood, ascites supernatant, and tumor cells Blood hemoglobin, erythrocytes, packed cell volume and leukocytes (eosinophils, basophils, and lymphocytes) were also decreased along with the development of various morphological abnormalities in erythrocytes (microcytes, macrocytes, echinocytes, acanthocytes, etc) after cisplatin treatment All these hematotoxic features were noted to be increased more when buthionine sulfoximine (a specific glutathione-depleting agent) was also given prior to cisplatin treatment However, combination treatment of cysteine (precursor for glutathione synthesis) plus cisplatin resulted in an improvement in the glutathione levels and decrease in hematological toxicities It is noted that the glutathione levels in blood and abnormalities in erythrocytes and other hematological parameters are inversely related in cisplatin-mediated cancer chemotherapy It is suggested that blood glutathione may play an important role in the development of cisplatin-mediated hematological toxicity in the host

Transmutation of 129I and 237Np using spallation neutrons produced by 1.5, 3.7 and 7.4GeV protons

Abstract: Small samples of 129I and 237Np, two long-lived radwaste nuclides, were exposed to spallation neutron fluences from relatively small metal targets of lead and uranium, that were surrounded with a 6 cm thick paraffin moderator, and irradiated with 1.5, 3.7 and 7.4 GeV protons. The (n,γ) transmutation rates were determined for these nuclides. Conventional radiochemical La- and U-sensors and a variety of solid-state nuclear track detectors were irradiated simultaneously with secondary neutrons. Compared with results from calculations with well-known cascade codes (LAHET from Los Alamos and DCM/CEM from Dubna), the observed secondary neutron fluences are larger.

Inhibition of cell proliferation and antitumor activity of a novel organotin compound

Abstract: Organotin compounds showed more antineoplastic effect against P388 leukemia in mice than any other class of compounds. However, they have not received as much attention as the platinum compounds. The present compound, Et 2 SnCl 2 .L [L = N-(2-pyridylmethylene)-4-toluidine] (OTC), showed an Sn-N bond length of 2.46 A which, because it is bigger than 2.39 A, is expected to achieve better formation of tin-DNA complexes. We previously reported on the synthesis and biological activity of this compound and on its ability to cause a delay in cell proliferation and sister chromatid exchanges in mouse bone marrow cells. In this study, we carried out further investigations on the antiproliferative and antitumor activity of OTC in relation to the cellular glutathione (GSH) level, which plays an important role in the cellular defense mechanism. OTC induced significant delay in the cell cycle in mouse bone marrow cells and, when the GSH level was low, the extent of the delay was reduced. The antitumor activity was determined in accordance with the US National Cancer Institute (NCI) standard protocol for primary screening in Dalton's lymphoma (DL) that was maintained by serial intraperitoneal transplantation. The T/C (treated/control) value was 146% when organotin was treated after transplantation; this improved significantly when buthionine sulfoximine (BSO), a GSH-depleting agent, was added 24 hours before the tin treatment. Our data suggest that the present tin compound has antiproliferative ability and can increase the survival of mice bearing DL. The endogenous GSH level influences the effect of the tin compound.

Exact expressions for minor hysteresis loops in the random field Ising model on a Bethe lattice at zero temperature.

Abstract: We obtain exact expressions for the minor hysteresis loops in the ferromagnetic random field Ising model on a Bethe lattice at zero temperature in the case when the driving field is cycled infinitely slowly.

Biodiversity of Rotifera in some tropical floodplain lakes of the Brahmaputra river basin, Assam (N.E. India)

Abstract: One hundred and sixteen species of Rotifera are recorded from seven floodplain lakes of the Brahmaputra basin (northeastern India), the highest rotifer biodiversity recorded from these biotopes in the Indian subcontinent to date The Australasian Brachionus dichotomus reductus and Lecane batillifer; the Oriental Keratella edmondsoni, Lecane blachei and L acanthinula; the Palaeotropical Lecane braumi, L lateralis, L unguitata, Trichocerca tropis, Testudinella greeni and T brevicaudata; the Pantropical Brachionus donneri and a rather widely distributed Horaella brehmi represent taxa of biogeographical interest Three species are new additions to the Indian rotifer fauna and eight are new to the NE region Lecanidae > Brachionidae = Colurellidae > Trichocercidae > Testudinellidae comprise the largest fraction (680%) of the examined fauna Comments are made on the general nature and composition of the rotifer taxocoenosis as well as on acidophilic elements, ecology of various taxa and on the species richness of different lakes

Photoreduction of iron protoporphyrin IX chloride in non‐ionic triton X‐100 micelle studied by electronic absorption and resonance Raman spectroscopy

Abstract: Resonance Raman and electronic absorption studies of iron protoporphyrin IX chloride (hemin) in non-ionic Triton X-100 micelle in the absence and presence of hindered imidazole (2-methylimidazole and 1,2-dimethylimidazole) and unhindered imidazole under various experimental conditions are reported. Hemin undergoes photoreduction at the metal center, both in the absence and presence of hindered imidazole, in anaerobic, alkaline and neutral pH conditions on photoexcitation by laser radiation at 441.6 and 457.9 nm. It is inferred from this study that only the monomer hemin encapsulated within the micelle under the alkaline pH conditions is photoreducible. The photoreduction of hemin in this micelle occurs from an electron transfer as a result of dissociation of coordinated hydroxyl ion to the iron atom in the photoexcited state, which may also involve the OHFe charge transfer transition around 360 nm. Copyright © 2001 John Wiley & Sons, Ltd.

Modulation of hepatic and renal glucocorticoid receptors during aging of mice.

Abstract: The regulation of hepatic and renal glucocorticoid receptors (GRs) in young(4 weeks) and senescent (120 weeks) mice was studied. Significant changesin the level of GRs from liver and kidney were detected, whereas theaffinity (K d) for the hormone [3H]dexamethasone did notchange in young and old mice. The concentration of GRs was markedlydecreased in liver (25%) and kidney (33%) of old mice as compared toyoung ones. The magnitude of heat activation of GR complexes was morepronounced in both the tissues at young age compared to old. In addition,we have found changes in the heat activation-inhibition studies of GRs,using polyunsaturated fatty acids (PUFAs) as measured by binding toDNA-cellulose and purified nuclei. Linoleic acid (C18:2) exhibited significantdecrease in heat activation of both hepatic and renal hormone-bound GR,with higher magnitude of inhibition in young liver (64%) and kidney (68%)as compared to old (41% and 43%, respectively). Arachidonic acid (C20:4)was also found to be an inhibitor of activation causing significant decreasein hepatic GR activation, with greater inhibition in young liver with respectto old, however, without any such difference in the kidney of young and oldmice. Furthermore, DNase I digestion and extraction of nuclear-boundGR-complexes from both the tissues reveal lesser extraction in old liver (26%)and kidney (24%) compared to young tissues, indicating chromatincondensation with aging, thereby controlling the accessibility to suchtranscription factors as GRs. These findings indicate that the changes inthe GR concentration, activation-modulation by PUFAs and chromatinorganization, that take place during aging, may contribute to functionalchanges in glucocorticoid action mechanisms in senescent animals.

Persistence in one-dimensional Ising models with parallel dynamics.

Abstract: We study persistence in one-dimensional ferromagnetic and antiferromagnetic nearest-neighbor Ising models with parallel dynamics. The probability $P(t)$ that a given spin has not flipped up to time t, when the system evolves from an initial random configuration, decays as $P(t)\ensuremath{\sim}{1/t}^{{\ensuremath{\theta}}_{p}}$ with ${\ensuremath{\theta}}_{p}\ensuremath{\simeq}0.75$ numerically. A mapping to the dynamics of two decoupled $A+\stackrel{\ensuremath{\rightarrow}}{A}0$ models yields ${\ensuremath{\theta}}_{p}=3/4$ exactly. A finite size scaling analysis clarifies the nature of dynamical scaling in the distribution of persistent sites obtained under this dynamics.

Dynamics of electric-field-induced molecular reorientation of a surface-stabilized antiferroelectric liquid crystal in the smectic-C* phase probed by time-resolved infrared spectroscopy.

Abstract: Polarization dependent and time-resolved Fourier transform infrared studies have been carried out on the electric-field-induced ferroelectric phase (Sm-C*) of a chiral, antiferroelectric liquid crystal at different temperatures. Polarization dependent infrared spectra under dc electric field reveal that the average alkyl chain axis does not coincide with the mesogen axis and is less tilted with respect to the layer normal than the mesogen. The analysis of the various absorbance profiles obtained from temporal response of absorption changes of infrared bands at different time delays provides clear evidence for biased orientation and hindered rotation of almost all the molecular segments around the average molecular long axis and the rotation of the whole molecule around its axis is also hindered. It is further inferred that the mesogen, the chiral segment, and the alkyl chains reach their equilibrium orientations at nearly the same time on switching the polarity of the ac electric field but the different molecular segments reorient through different angles.

Synthesis of substituted hexa-3,5-dienoic acid methyl esters from conjugated dienones

Abstract: Substituted hexa-3,5-dienoic acid methyl esters (2) were conveniently prepared in one step by 1,2-carbonyl transposition of the corresponding dienones (1) using lead(IV) acetate and boron trifluoride–diethyl ether in benzene at room temperature.

Wobble base-pairing in codon-anticodon interactions: a theoretical modelling study.

Abstract: The Crick wobble hypothesis attributes the phenomenon of codon degeneracy to a certain impreciseness of pairing between the third base of the codon and the first base of the anticodon. This theoretical study investigates the pairing properties of some wobble bases, including both, observed and unobserved pairs. Some wobble base-pairs are predicted to follow the Watson-Crick pairs in configuration and pairing facility, while others deviate from this norm. The observed U:V pair is unique in that a pairing configuration may be suggested for it wherein the hydrogen-bonding involves the exocyclic 5-carboxymethoxy group of V. By comparing the theoretical data on the configurations of these pairs with the evidence for their existence/non-existence in nature, some guidelines emerge for differentiating between observed and unobserved base pairs on the basis of the pairing configuration.