183 research outputs found

    Regge behaviour of distribution functions and t and x-evolutions of gluon distribution function at low-x

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    In this paper t and x-evolutions of gluon distribution function from Dokshitzer-Gribov-Lipatov-Altarelli-Parisi(DGLAP) evolution equation in leading order(LO) at low-x, assuming the Regge behaviour of quark and gluon at this limit, are presented. We compare our results of gluon distribution function with MRST 2001, MRST 2004 and GRV '98 parameterizations and show the compatibility of Regge behaviour of quark and gluon distribution functions with perturbative quantum chromodynamics(PQCD) at low-x. We also discuss the limitations of Taylor series expansion method used earlier to solve DGLAP evolution equations, in the Regge behaviour of distribution functions.Comment: 19 pages, 7 figure

    Lowering solar mixing angle in inverted hierarchy without charged lepton corrections

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    In the present work, the inverted hierarchical neutrino mass model which is characterised by opposite CP parity in the first two mass eigenvalues (m1,−m2,m3)(m_1,-m_2,m_3), is studied in order to lower the predicted value of solar mixing angle tan⁡2ξ12\tan^2\theta_{12}, from the tri-bimaximal mixing (TBM), without sacrificing the conditions of maximal atmospheric mixing angle and zero reactor angle. The present attempt is different from the earlier approach where the correction from the charged lepton mass matrix is included in the leptonic mixing matrix to lower the prediction on solar mixing angle. The lowering of the solar mixing angle without charged lepton correction, can be obtained through the variation of the input value of a flavour twister term present in the texture of neutrino mass matrix having a 2-3 symmetry. The present analysis agrees with the latest experimental bounds on neutrino mass parameters and also represents an important result on the survival of the inverted hierarchical neutrino mass models having opposite CP parity in the first two eigenvalues.Comment: 10 pages, two figures. Accepted for publication in Journal of Physics G:Nuclear and Particle Physic

    Obesity-induced insulin resistance in human skeletal muscle is characterised by defective activation of p42/p44 MAP kinase

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    Insulin resistance (IR), an impaired cellular, tissue and whole body response to insulin, is a major pathophysiological defect of type 2 diabetes mellitus. Although IR is closely associated with obesity, the identity of the molecular defect(s) underlying obesity-induced IR in skeletal muscle remains controversial; reduced post-receptor signalling of the insulin receptor substrate 1 (IRS1) adaptor protein and downstream effectors such as protein kinase B (PKB) have previously been implicated. We examined expression and/or activation of a number of components of the insulin-signalling cascade in skeletal muscle of 22 healthy young men (with body mass index (BMI) range, 20–37 kg/m2). Whole body insulin sensitivity (M value) and body composition was determined by the hyperinsulinaemic (40 mU. min−1.m−2.), euglycaemic clamp and by dual energy X-ray absorptiometry (DEXA) respectively. Skeletal muscle (vastus lateralis) biopsies were taken before and after one hour of hyperinsulinaemia and the muscle insulin signalling proteins examined by western blot and immunoprecipitation assay. There was a strong inverse relationship between M-value and BMI. The most striking abnormality was significantly reduced insulin-induced activation of p42/44 MAP kinase, measured by specific assay, in the volunteers with poor insulin sensitivity. However, there was no relationship between individuals' BMI or M-value and protein expression/phosphorylation of IRS1, PKB, or p42/44 MAP kinase protein, under basal or hyperinsulinaemic conditions. In the few individuals with poor insulin sensitivity but preserved p42/44 MAP kinase activation, other signalling defects were evident. These findings implicate defective p42/44 MAP kinase signalling as a potential contributor to obesity-related IR in a non-diabetic population, although clearly multiple signalling defects underlie obesity associated IR

    Deviation from tri-bimaximal mixings in two types of inverted hierarchical neutrino mass models

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    An attempt is made to explore the possibility for deviations of solar mixing angle (Ξ12\theta_{12}) from tri-bimaximal mixings, without sacrificing the predictions of maximal atmospheric mixing angle (Ξ23=π/4\theta_{23}=\pi/4) and zero reactor angle (Ξ13=0\theta_{13}=0). We find that the above conjecture can be automatically realised in the inverted hierarchical neutrino mass model having 2-3 symmetry, in the basis where charged lepton mass matrix is diagonal. For the observed ranges of △m212\bigtriangleup m^2_{21} and \bigtriangleup m^2_{23], we calculate the predictions on tan⁥2Ξ12=0.5,0.45,0.35\tan^2\theta_{12}=0.5, 0.45, 0.35 for different input values of the parameters in the neutrino mass matrix. We also observe a possible crossing over from one type of inverted hierarchical model having same CP parity (Type-IHA) to other type having opposite CP parity (Type-IHB). Such neutrino mass matrices can be obtained from the canonical seesaw formula using diagonal form of Dirac neutrino mass matrix and non-diagonal texture of right-handed Majorana mass matrix, and may have important implications in model building using discrete as well as non-abelian symmetry groups.Comment: 13 pages, 7 figure

    Regge behaviour of distribution functions and evolution of gluon distribution function in Next-to-Leading order at low-x

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    Evolution of gluon distribution function from Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equation in next-to-leading order (NLO) at low-x is presented assuming the Regge behaviour of quarks and gluons at this limit. We compare our results of gluon distribution function with MRST2004, GRV98LO and GRV98NLO parameterizations and show the compatibility of Regge behaviour of quark and gluon distribution functions with perturbative quantum chromodynamics (PQCD) at low-x.Comment: 12 pages, 4 figure

    Detection of species-specific genetic markers in goat, sheep and pig by molecular characterization of Cytochrome b gene

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    Present work was designed to know the inter-species genetic variation by detecting polymorphisms and analysing the nucleotide sequences of cytochrome b gene. Blood samples were collected from apparently healthy adult animals of indigenous goat, sheep and pig of Asom, and mitochondrial DNA was extracted for amplification by PCR. One half of the PCR product was used for restriction digestion while the other half after purification was sent for sequencing. Species specific restriction patterns were observed for cytochrome b gene amplicon upon digestion with AluI, HinfI, and HaeIII. The nucleotide sequence results were further analyzed using ClustalW and Mega5 softwares for unambiguous species typing. The percent similarity study showed that goat cytochrome b gene had 89.64 and 82.12% similarity with sheep and pig respectively. Phylogenetic tree also revealed close relationship of goat and sheep cytochrome b gene. Lowest pair wise distance was observed between goat and sheep (0.123) followed by goat and pig (0.227). Pig and sheep cytochrome b gene showed the highest degree of pair wise distance (0.255) between the nucleotides. From the present study, it can be concluded that RFLP and sequence analysis of cytochrome b gene provided the information about the extent of inter-species genetic diversity and can be used as a powerful tool for genetic traceability of species

    Fabrication and characterization of Eri silk fibers-based sponges for biomedical application

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    Cocoon-derived semi-domesticated Eri silk fibers still lack exploitation for tissue engineering applications due to their poor solubility using conventional methods. The present work explores the ability to process cocoon fibers of non-mulberry Eri silk (Samia/Philosamia ricini) into sponges through a green approach using ionic liquid (IL) Ăą 1-buthyl-imidazolium acetate as a solvent. The formation of ÎÂČ-sheet structures during Eri silk/IL gelation was acquired by exposing the Eri silk/IL gels to a saturated atmosphere composed of two different solvents: (i) isopropanol/ethanol (physical stabilization) and (ii) genipin, a natural crosslinker, dissolved in ethanol (chemical crosslinking). The sponges were then obtained by freeze-drying. This approach promotes the formation of both stable and ordered non-crosslinked Eri silk fibroin matrices. Moreover, genipin-crosslinked silk fibroin sponges presenting high height recovery capacity after compression, high swelling degree and suitable mechanical properties for tissue engineering applications were produced. The incorporation of a model drug Ăą ibuprofen Ăą and the corresponding release study from the loaded sponges demonstrated the potential of using these matrices as effective drug delivery systems. The assessment of the biological performance of ATDC5 chondrocyte-like cells in contact with the developed sponges showed the promotion of cell adhesion and proliferation, as well as extracellular matrix production within two weeks of culture. SpongesĂą intrinsic properties and biological findings open up their potential use for biomedical applications.The authors SSS, DSC, MBO, NMO acknowledge financial support from Portuguese Foundation for Science and Technology – FCT (Grants SFRH/BPD/45307/2008, SFRH/BPD/85790/2012, SFRH/BD/71396/2010 and SFRH/BD/73172/2010, respectively), ‘‘Fundo Social Europeu” – FSE, and ‘‘Programa Diferencial de Potencial Humano POPH”. This work is also financially supported by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n REGPOT-CT2012-316331-POLARIS and from Fundação para a CiĂȘncia e Tecnologia (FCT) through the project ENIGMA – PTDC/EQU-EPR/121491/2010. The laboratory work of SCK is supported by Department of Biotechnology and Indian Council of Medical Research, Govt of India. SCK and RLR acknowledge their short visits either Institutes. SCK is also grateful to 3BÂŽ s Research Group- Biomaterials, Biodegradables and Biomimetics, University of Minho, Portugal for providing facilities during his short visit
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