1,380 research outputs found

    Golden Horn Estuary: Description of the ecosystem and an attempt to assess its ecological quality status using various classification metrics

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    In this paper, we describe the pelagic and benthic ecosystem of the Golden Horn  estuary opening into the Marmara Sea. To improve the water quality of the estuary, which had long been subject to severe anthropogenic pollution (industrial, chemical, shipping),  industrial facilities were moved from the estuary in the 1980s, followed by a rehabilitation plan in the 1990s. Our results, based on chemical parameters and phytoplankton showed some signs of improvement of water conditions in the upper layer. However, macrozoobenthic findings of this study did not reflect such a recovery in bottom life.An approach to the Ecological Quality Status (EQS) assessment was performed by applying the biotic indices BENTIX, AMBI, BOPA, BO2A. Our final assessment was based on 'expert-judgements' and revealed a very disturbed overall ecosystem with 'bad' EQS for the station at the head of the estuary,  'poor' in the rest of the estuary and 'moderate' EQS only in the middle station

    Engineered Protein Polymer-Gold Nanoparticle Hybrid Materials for Small Molecule Delivery

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    We have fabricated protein polymer-gold nanoparticle (P-GNP) nanocomposites that exhibit enhanced binding and delivery properties of the small hydrophobic molecule drug, curcumin, to the model breast cancer cell line, MCF-7. These hybrid biomaterials are constructed via in situ GNP templated-synthesis with genetically engineered histidine tags. The P-GNP nanocomposites exhibit enhanced small molecule loading, sustained release and increased uptake by MCF-7 cells. When compared to the proteins polymers alone, the P-GNPs demonstrate a greater than 7-fold increase in curcumin binding, a nearly 50% slower release profile and more than 2-fold increase in cellular uptake of curcumin. These results suggest that P-GNP nanocomposites serve as promising candidates for drug delivery vehicles

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    Immigration represents a promising counter-narrative for Rust Belt cities in the 21st century. Increasingly, both immigrants and refugees are part of the comeback stories of Northeastern and Midwestern cities from Buffalo, to Dayton and Pittsburgh. This review explores recent research in urban geography and allied disciplines focusing on the international migration patterns, processes, and politics reshaping the urban geography of the American Rust Belt. Recent research sheds crucial light on how im/migrant lives are reshaping urban landscapes of Rust Belt cities, and conversely, how local immigration policies in these cities are rearranging the uneven geographies of immigrant receptivity across the U.S. Overall, this review highlights the limitations of the singular spatial imaginary of the Rust Belt advanced previously by many urbanists. Rather, this review illustrates the rich, complex, and tangled contemporary spatial nuances associated with international migration in this region. These spatial nuances are complicated by increasingly exclusionary immigration policy and rhetoric at the federal level since January of 2017

    Mechanism of action of probiotics

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    The modern diet doesn't provide the required amount of beneficial bacteria. Maintenance of a proper microbial ecology in the host is the main criteria to be met for a healthy growth. Probiotics are one such alternative that are supplemented to the host where by and large species of Lactobacillus, Bifidobacterium and Saccharomyces are considered as main probiotics. The field of probiotics has made stupendous strides though there is no major break through in the identification of their mechanism of action. They exert their activity primarily by strengthening the intestinal barrier and immunomodulation. The main objective of the study was to provide a deep insight into the effect of probiotics against the diseases, their applications and proposed mechanism of action

    LOFAR discovery of a double radio halo system in Abell 1758 and radio/X-ray study of the cluster pair

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    Radio halos and radio relics are diffuse synchrotron sources that extend over Mpc-scales and are found in a number of merger galaxy clusters. They are believed to form as a consequence of the energy that is dissipated by turbulence and shocks in the intra-cluster medium (ICM). However, the precise physical processes that generate these steep synchrotron spectrum sources are still poorly constrained. We present a new LOFAR observation of the double galaxy cluster Abell 1758. This system is composed of A1758N, a massive cluster hosting a known giant radio halo, and A1758S, which is a less massive cluster whose diffuse radio emission is confirmed here for the first time. Our observations have revealed a radio halo and a candidate radio relic in A1758S, and a suggestion of emission along the bridge connecting the two systems which deserves confirmation. We combined the LOFAR data with archival VLA and GMRT observations to constrain the spectral properties of the diffuse emission. We also analyzed a deep archival Chandra observation and used this to provide evidence that A1758N and A1758S are in a pre-merger phase. The ICM temperature across the bridge that connects the two systems shows a jump which might indicate the presence of a transversal shock generated in the initial stage of the merger

    Increased risk of tuberculosis in health care workers: a retrospective survey at a teaching hospital in Istanbul, Turkey

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    BACKGROUND: Tuberculosis (TB) is an established occupational disease affecting health care workers (HCWs). Determining the risk of TB among HCWs is important to enable authorites to take preventative measures in health care facilities and protect HCWs. This study was designed to assess the incidence of TB in a teaching hospital in Istanbul, Turkey. This study is retrospective study of health records of HCWs in our hospital from 1991 to 2000. RESULTS: The mean workforce of the hospital was 3359 + 33.2 between 1991 and 2000. There were 31 cases (15 male) meeting the diagnostic criteria for TB, comprising eight doctors, one nurse and 22 other health professionals. Mean incidence of TB was 96 per 100,000 for all HCWs (relative risk: 2.71), 79 per 100,000 for doctors (relative risk: 2.2), 14 per 100,000 for nurses and 121 per 100,000 (relative risk: 3.4) for other professionals. The mean incidence of TB in Turkey between 1991 and 2000 was 35.4 per 100,000. Incidence of TB was similar in the Departments of Chest Diseases and Clinical Medicine but there were no TB cases in the Basic Science and Managerial Departments. CONCLUSION: HCWs in Turkey who work in clinics have an increased risk for TB. Post-graduate education and prevention programs reduce the risk of TB. Control programs to prevent nosocomial transmission of TB should be established in hospitals to reduce risk for HCWs

    Growth inhibition of oral mutans streptococci and candida by commercial probiotic lactobacilli - an in vitro study

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    <p>Abstract</p> <p>Background</p> <p>Probiotic bacteria are suggested to play a role in the maintenance of oral health. Such health promoting bacteria are added to different commercial probiotic products. The aim of the study was to investigate the ability of a selection of lactobacilli strains, used in commercially available probiotic products, to inhibit growth of oral mutans streptococci and <it>C. albicans in vitro</it>.</p> <p>Methods</p> <p>Eight probiotic lactobacilli strains were tested for growth inhibition on three reference strains and two clinical isolates of mutans streptococci as well as two reference strains and three clinical isolates of <it>Candida albicans </it>with an agar overlay method.</p> <p>Results</p> <p>At concentrations ranging from 10<sup>9 </sup>to 10<sup>5 </sup>CFU/ml, all lactobacilli strains inhibited the growth of the mutans streptococci completely with the exception of <it>L. acidophilus </it>La5 that executed only a slight inhibition of some strains at concentrations corresponding to 10<sup>7 </sup>and 10<sup>5 </sup>CFU/ml. At the lowest cell concentration (10<sup>3 </sup>CFU/ml), only <it>L. plantarum </it>299v and <it>L. plantarum </it>931 displayed a total growth inhibition while a slight inhibition was seen for all five mutans streptococci strains by <it>L. rhamnosus </it>LB21, <it>L. paracasei </it>F19, <it>L. reuteri </it>PTA 5289 and <it>L. reuteri </it>ATCC 55730. All the tested lactobacilli strains reduced candida growth but the effect was generally weaker than for mutans streptococci. The two <it>L. plantarum </it>strains and <it>L. reuteri </it>ATCC 55730 displayed the strongest inhibition on <it>Candida albicans</it>. No significant differences were observed between the reference strains and the clinical isolates.</p> <p>Conclusion</p> <p>The selected probiotic strains showed a significant but somewhat varying ability to inhibit growth of oral mutans streptococci and <it>Candida albicans in vitro</it>.</p

    Single-Cell Virology: On-Chip Investigation of Viral Infection Dynamics

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    We have developed a high-throughput, microfluidics-based platform to perform kinetic analysis of viral infections in individual cells. We have analyzed thousands of individual poliovirus infections while varying experimental parameters, including multiplicity of infection, cell cycle, viral genotype, and presence of a drug. We make several unexpected observations masked by population-based experiments: (1) viral and cellular factors contribute uniquely and independently to viral infection kinetics; (2) cellular factors cause wide variation in replication start times; and (3) infections frequently begin later and replication occurs faster than predicted by population measurements. We show that mutational load impairs interaction of the viral population with the host, delaying replication start times and explaining the attenuated phenotype of a mutator virus. We show that an antiviral drug can selectively extinguish the most-fit members of the viral population. Single-cell virology facilitates discovery and characterization of virulence determinants and elucidation of mechanisms of drug action eluded by population methods. Guo et al. use a microfluidics device installed on a fluorescence microscope to monitor the kinetics of viral infection in single cells. Between-cell variation in outcomes of infection exists at all phases of the life cycle. Cellular gene expression governs the eclipse phase; viral genetics govern replication rate and yield

    BAT AGN Spectroscopic Survey XXVII: Scattered X-Ray Radiation in Obscured Active Galactic Nuclei

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    Accreting supermassive black holes (SMBHs), also known as active galactic nuclei (AGN), are generally surrounded by large amounts of gas and dust. This surrounding material reprocesses the primary X-ray emission produced close to the SMBH and gives rise to several components in the broadband X-ray spectra of AGN, including a power-law possibly associated with Thomson-scattered radiation. In this work, we study the properties of this scattered component for a sample of 386 hard-X-ray-selected, nearby (z0.03z \sim 0.03) obscured AGN from the 70-month Swift/BAT catalog. We investigate how the fraction of Thomson-scattered radiation correlates with different physical properties of AGN, such as line-of-sight column density, X-ray luminosity, black hole mass, and Eddington ratio. We find a significant negative correlation between the scattering fraction and the column density. Based on a large number of spectral simulations, we exclude the possibility that this anti-correlation is due to degeneracies between the parameters. The negative correlation also persists when considering different ranges of luminosity, black hole mass, and Eddington ratio. We discuss how this correlation might be either due to the angle dependence of the Thomson cross-section or to more obscured sources having a higher covering factor of the torus. We also find a positive correlation between the scattering fraction and the ratio of [OIII] λ\lambda5007 to X-ray luminosity. This result is consistent with previous studies and suggests that the Thomson-scattered component is associated with the narrow-line region.Comment: Accepted for publication in MNRAS, 18 pages, 9 figures, 2 tables, 1 equatio
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