5,304 research outputs found

    Developmental features of biomedical bibliographic databases

    Get PDF
    The genesis of bibliographic databases can be traced to the abstracting and indexing (A&I) periodicals. The Journal Des Scavans published in 1665 did contain abstracts of articles, but the formal abstracting journal began in 1820 (English) and in 1830 (German). The growth of primary periodicals required libraries to subscribe to A&I services to search for papers scattered in different journals as it was not possible to acquire all the primary periodical titles. The electronic versions of A&I periodicals started appearing in 1960s with emergence of database concept. The Chemical Titles and the MEDLARS are considered to be the earliest bibliographic databases. The Silver Platter is believed publish first biomedical CD-ROM database the MEDLINE with search facility � SPIRS. The growth and development of bibliographic databases has continued since then and enters the digital era to serve the users. The present paper theoretically examines EMBASE, PubMed and IndMed databases. © 2017, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved

    Alterations in sperm characteristics of follicle-stimulating hormone (FSH)-immunized men are similar to those of FSH-deprived infertile male bonnet monkeys

    Get PDF
    The quality of sperm ejaculated by bonnet monkeys and normal, healthy proven fertile volunteer men, both actively immunized with ovine follicle-stimulating hormone (oFSH), was examined at different times of study for chromatin packaging and acrosomal glycoprotein concentration by flow cytometry. Susceptibility of sperm nuclear DNA to dithiothreitol (DTT)-induced decondensation, as measured by ethidium bromide binding, was markedly high compared with values at day 0 in men and monkeys during periods when FSH antibody titer was high. Sperm chromatin structure assay yields alphat values, which is another index of chromatin packaging. Higher alphat values, signifying poor packaging, occurred in both species following immunization with heterologous pituitary FSH. The binding of fluorosceinated pisum sativum agglutinin (PSA-FITC) to acrosome of sperm of monkeys and men was significantly low, compared with values at day 0 (control) during periods when cross-reactive FSH antibody titer was high and endogenous FSH was not detectable. Blockade of FSH function in monkeys by active immunization with a recombinant oFSH receptor protein corresponding to a naturally occurring messenger RNA (mRNA) also resulted in production of sperm with similar defects in chromatin packaging and reduced acrosomal glycoprotein concentration. Thus, it appears that in monkeys and men, lack of FSH signaling results in production of sperm that exhibit defective chromatin packaging and reduction in acrosomal glycoprotein content. These characteristics are similar to that exhibited by sperm of some class of infertile men. Interestingly, these alterations in sperm quality occur well ahead of decreased sperm counts in the ejaculate

    Immunobiology of a synthetic luteinizing hormone receptor peptide 21-41

    Get PDF
    Immunization of adult male rabbits with a synthetic luteinizing hormone-receptor peptide (LH-RP; representing amino-acids 21-41 of the extracellular domain of the rat LH receptor) resulted in production of high-titer antibodies capable of interacting with particulate and cell-based LH receptors. The antibody produced was able to inhibit binding of 125I-labeled human chorionic gonadotropin (hCG) to a particulate sheep luteal LH receptor preparation by 40%-50%. Maximal inhibitory activity was correlated with high antibody titer. Immunocytometry revealed that the antibody could directly bind to cells having LH receptors, such as rat granulosa and Leydig cells. The antibodies recognized a 77-kilodalton membrane protein in Western blots of mouse testicular extracts. Interaction of endogenous Leydig cell LH receptor with the LH-RP antibody resulted in both hormone agonist and antagonistic activities. The hormone-mimicking activity (increase in serum testosterone over control) was confined only to the early phase of immunization when the antibody titer was low. Blockade of LH receptor during the later part of immunization resulted in a significant reduction in serum testosterone over controls and inhibition of spermatogenesis. DNA flow cytometry showed that a specific and significant inhibition of meiosis (transformation of primary spermatocytes to round and elongated spermatids P < .01) and spermiogenesis (transformation of round spermatids to elongated spermatids P < .0001) occurred following blockade of LH function

    Design and Synthesis of a Novel N-(1H-tetrazol-5-yl)methyl Cyclic Peptoid Using Nosyl-protected N-(1-trityl-1H-tetrazol-5-yl)methyl Substituted Glycine

    Get PDF
    Abstract: A solid phase synthesis of a cyclic peptoid bearing (1H-tetrazol-5-yl)methyl as N-substituent has been developed employing the monomer approach. The requisite monomeric Nosyl-protected N-(1-trityl-1H-tetrazol-5-yl)methyl substituted glycine was accessed by a convenient synthesis involving Click reaction of Nosyl-protected N-(cyanomethyl)glycine methyl ester and sodium azide as a key step. This building block was then employed in the solid phase synthesis of a tetramer peptoid. The linear tetramer was subjected to macrocyclization using PyBOP to obtain a cyclic peptoid with (1H-tetrazol-5-yl)methyl pendants in good yield. © 2017, Springer Science+Business Media New York

    "Exhaustion" Physics in the Periodic Anderson Model using Iterated Perturbation Theory

    Get PDF
    We discuss the "exhaustion" problem in the context of the Periodic Anderson Model using Iterated Perturbation Theory(IPT) within the Dynamical Mean Field Theory. We find that, despite its limitations, IPT captures the exhaustion physics, which manifests itself as a dramatic, strongly energy dependent suppression of the effective Anderson impurity problem. As a consequence, low energy scales in the lattice case are strongly suppressed compared to the "Kondo scale" in the single-impurity picture. The IPT results are in qualitative agreement with recent Quantum Monte Carlo results for the same problem.Comment: 13 preprint pages including 1 table and 4 eps figures, replaced by revised version, accepted for publication in Europhysics Letters, added references and conten

    Seaweed culture in India-an appraisal

    Get PDF
    In recent years there has been a steady increase in the demand for naturally occuring seaweeds as a result of many seaweed based industries coming up. In order to meet the raw material requirement of these industries attempts have been made in this country to develop suitable seaweed farming techniques by some Institutes notably the CMFRI at its Mandepam. Regional Centre and CSMCRI at its field centre, Mandapam. Experimental culture of economically important seaweeds such as Gracllaria edulis, Gelidiella acerosa and other species was undertaken since 1972 at Mandapam- in these experiments production rates ranging from 3 to 8 times the initial wet weight were obtained. The techniques of seaweed culture, the favourable seasons optimum duration of culture period and the influence of environmental parameters are discussed in this account with notes on economics of seaweed culture. General information on the seaweed resources slong our coasts, their potential for exploitation and culture are also highlighted

    Coarsening and Slow-Dynamics in Granular Compaction

    Full text link
    We address the problem of the microscopic reorganization of a granular medium under a compaction process in the framework of Tetris-like models. We point out the existence of regions of spatial organization which we call domains, and study their time evolution. It turns out that after an initial transient, most of the activity of the system is concentrated on the boundaries between domains. One can then describe the compaction phenomenon as a coarsening process for the domains, and a progressive reduction of domain boundaries. We discuss the link between the coarsening process and the slow dynamics in the framework of a model of active walkers on active substrates.Comment: Revtex 4 pages, 4 figures, in press in PRL. More info http://axtnt3.phys.uniroma1.it/Tetri

    The Exonuclease Activity of hPMC2 is Required for Transcriptional Regulation of The QR Gene and Repair of Estrogen-Induced Abasic Sites

    Get PDF
    We have previously reported that the expression of antioxidative stress enzymes is upregulated by trans-hydroxytamoxifen (TOT) in breast epithelial cell lines providing protection against estrogen-induced DNA damage. This regulation involves Estrogen Receptor β (ERβ) recruitment to the Electrophile Response Element (EpRE) and a novel protein, human homolog of Xenopus gene which Prevents Mitotic Catastrophe (hPMC2). We have also demonstrated that ERβ and hPMC2 are required for TOT-dependent recruitment of poly (ADP-ribose) polymerase 1 (PARP-1) and Topoisomerase IIβ (Topo IIβ) to the EpRE. Sequence analysis reveals that the C-terminus of hPMC2 encodes a putative exonuclease domain. Using in vitro kinetic assays, we found that hPMC2 is a 3\u27-5\u27 non-processive exonuclease that degrades both single-stranded and double-stranded substrates. Mutation of two conserved carboxylate residues drastically reduced the exonuclease activity of hPMC2, indicating the relative importance of the catalytic residues. Western blot analysis of breast cancer cell lines for Quinone Reductase (QR) levels revealed that the intrinsic exonuclease activity of hPMC2 was required for TOT-induced QR upregulation. Chromatin immunoprecipitation (ChIP) assays also indicated that hPMC2 was involved in the formation of strand breaks observed with TOT treatment and is specific for the EpRE-containing region of the QR gene. We also determined that the transcription factor NF-E2-related factor-2 (Nrf2) is involved in the specificity of hPMC2 for the EpRE. In addition, we determined that the catalytic activity of hPMC2 is required for repair of abasic sites that result from estrogen-induced DNA damage. Thus, our study provides a mechanistic basis for transcriptional regulation by hPMC2 and provides novel insights into its role in cancer prevention

    Correlation between prevalence rates of pulmonary tuberculosis, tuberculous infection and non-specific sensitivity

    Get PDF
    Data from the initial examination of a BCG trial have been analysed to determine mathematical relationship, if any, between the prevalence of infection and disease. Also, because non-specific sensitivity otters protection against the development of tuberculosis and because there was high prevalence of nonspecific sensitivity in the area of the study, relationship between nonspecific sensitivity and tuberculosis had also been studied. Results of the analysis showed that relationship between prevalence of tuberculous infection and disease is not amenable to any simple mathematical quantification. However, the values of the coefficients of correlation between the two were statistically highly significant suggesting that the prevalence of one varied directly with the prevalence of the other in the community, and that preve-lence of infection may be used as an indicator for the prevalence of disease at different points of time. The analysis also showed the existence of an inverse relationship between prevalence of tuber-culosis ane prevalence of non-specific sensitivity tending to confirm the previous finding that the latter offered protection against the other

    Finite-temperature effects on the superfluid Bose-Einstein condensation of confined ultracold atoms in three-dimensional optical lattices

    Full text link
    We discuss the finite-temperature phase diagram in the three-dimensional Bose-Hubbard (BH) model in the strong correlation regime, relevant for Bose-Einstein condensates in optical lattices, by employing a quantum rotor approach. In systems with strong on site repulsive interactions, the rotor U(1) phase variable dual to the local boson density emerges as an important collective field. After establishing the connection between the rotor construction and the the on--site interaction in the BH model the robust effective action formalism is developed which allows us to study the superfluid phase transition in various temperature--interaction regimes
    corecore