658 research outputs found

    Prospects in cadmium-contaminated water management using free-living cyanobacteria (Oscillatoria sp.)

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    In this study, the removal of cadmium (Cd) by free-living Oscillatoria sp. was studied. Our results showed that maximal Cd removal efficiency (~60%) by the cyanobacterial culture was achieved within 12-24 h in the presence of 5.0 or 25.0 mg/L of Cd. The mechanisms underlying this phenomenon were explored by elemental analysis and FTIR-ATR spectroscopy. It was found that metal adsorption by negatively charged functional groups in the cyanobacterial biomass was the main mechanism used by Oscillatoria sp. to remove metal from the aqueous medium, followed by Cd bioaccumulation into living cells. Additionally, Cd-exposed microalgae showed increased oxidative stress (MDA formation), a decreased dehydrogenase activity, a higher amount of soluble carbohydrates and a decreased total carotenoid concentration, as compared to the control cells. These results suggest that Oscillatoria sp. improved its antioxidative defense system under stressful conditions, through carotenoid-mediated ROS quenching and induction of carbohydrate catabolism, in order to counteract the oxidative damage and preserve the photosynthetic machinery and cellular energetics. In fact, no significant reduction in Oscillatoria sp. cell density, total protein amount, and chlorophyll a content was observed after 24-h Cd exposure, even at the highest metal concentration tested (i.e., 25.0 mg/L). Hence, the presented results are the first to describe some new insights about the metabolic and physiological behavior of living Oscillatoria sp. during Cd remediation, and open up the possibility of finding an equilibrium that maximizes metal removal performance with an active cyanobacterial metabolism, to achieve a rewarding and sustainable management of industrial metal-polluted wastewater.Fil: Carralero Bon, Iván. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Química e Ingeniería del Rosario. Departamento de Investigación Institucional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Salvatierra, Lucas Matías. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Química e Ingeniería del Rosario. Departamento de Investigación Institucional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Lario, Luciana Daniela. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Química e Ingeniería del Rosario. Departamento de Investigación Institucional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Morató Farreras, Jordi. Universidad Politecnica de Catalunya. Escuela Superior de Ingenierías Industrial, Aeroespacial y Audiovisual de Terrassa. Cátedra Unesco de Sostenibilidad.; EspañaFil: Perez, Leonardo Martin. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Química e Ingeniería del Rosario. Departamento de Investigación Institucional; Argentina. Universidad Politecnica de Catalunya. Escuela Superior de Ingenierías Industrial, Aeroespacial y Audiovisual de Terrassa. Cátedra Unesco de Sostenibilidad.; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentin

    Stability of Cloud Orbits in the Broad Line Region of Active Galactic Nuclei

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    We investigate the global dynamic stability of spherical clouds in the Broad Line Region (BLR) of Active Galactic Nuclei (AGN), exposed to radial radiation pressure, gravity of the central black hole (BH), and centrifugal forces assuming the clouds adapt their size according to the local pressure. We consider both, isotropic and anisotropic light sources. In both cases, stable orbits exist also for very sub-Keplerian rotation for which the radiation pressure contributes substantially to the force budget. We demonstrate that highly eccentric, very sub-Keplerian stable orbits may be found. This gives further support for the model of Marconi et al. 2008, who pointed out that black hole masses might be significantly underestimated if radiation pressure is neglected. That model improved the agreement between black hole masses derived in certain active galaxies based on BLR dynamics, and black hole masses derived by other means in other galaxies by inclusion of a luminosity dependent term. For anisotropic illumination, energy is conserved for averages over long time intervals, only, but not for individual orbits. This leads to Rosetta orbits that are systematically less extended in the direction of maximum radiation force. Initially isotropic relatively low column density systems would therefore turn into a disk when an anisotropic AGN is switched on.Comment: 7 pages, 4 fig.s, accepted by MNRAS, some text was missing - correcte

    Abundances and search for vertical stratification in the atmospheres of four HgMn stars

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    Using high resolution, high-S/N archival UVES spectra, we have performed a detailed spectroscopic analysis of 4 chemically peculiar HgMn stars (HD 71066, HD 175640, HD 178065 and HD 221507). Using spectrum synthesis, mean photospheric chemical abundances are derived for 22 ions of 16 elements. We find good agreement between our derived abundances and those published previously by other authors. For the 5 elements that present a sufficient number of suitable lines, we have attempted to detect vertical chemical stratification by analyzing the dependence of derived abundance as a function of optical depth. For most elements and most stars we find no evidence of chemical stratification with typical 3\sigma upper limits of \Delta\log N_elem/N_tot~0.1-0.2 dex per unit optical depth. However, for Mn in the atmosphere of HD 178065 we find convincing evidence of stratification. Modeling of the line profiles using a two-step model for the abundance of Mn yields a local abundance varying approximately linearly by ~0.7 dex through the optical depth range log \tau_5000=-3.6 to -2.8.Comment: 11 figures, 9 tables, table 6-9 (online material), accepted by MNRA

    M48U1 and Tenofovir combination synergistically inhibits HIV infection in activated PBMCs and human cervicovaginal histocultures

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    Microbicides are considered a promising strategy for preventing human immunodeficiency virus (HIV-1) transmission and disease. In this report, we first analyzed the antiviral activity of the miniCD4 M48U1 peptide formulated in hydroxyethylcellulose (HEC) hydrogel in activated peripheral blood mononuclear cells (PBMCs) infected with R5-and X4-Tropic HIV-1 strains. The results demonstrate that M48U1 prevented infection by several HIV-1 strains including laboratory strains, and HIV-1 subtype B and C strains isolated from the activated PBMCs of patients. M48U1 also inhibited infection by two HIV-1 transmitted/founder infectious molecular clones (pREJO.c/2864 and pTHRO.c/2626). In addition, M48U1 was administered in association with tenofovir, and these two antiretroviral drugs synergistically inhibited HIV-1 infection. In the next series of experiments, we tested M48U1 alone or in combination with tenofovir in HEC hydrogel with an organ-like structure mimicking human cervicovaginal tissue. We demonstrated a strong antiviral effect in absence of significant tissue toxicity. Together, these results indicate that co-Treatment with M48U1 plus tenofovir is an effective antiviral strategy that may be used as a new topical microbicide to prevent HIV-1 transmission

    Type 1 interferons and Foxo1 down-regulation play a key role in age-related T-cell exhaustion in mice

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    Foxo family transcription factors are critically involved in multiple processes, such as metabolism, quiescence, cell survival and cell differentiation. Although continuous, high activity of Foxo transcription factors extends the life span of some species, the involvement of Foxo proteins in mammalian aging remains to be determined. Here, we show that Foxo1 is down-regulated with age in mouse T cells. This down-regulation of Foxo1 in T cells may contribute to the disruption of naive T-cell homeostasis with age, leading to an increase in the number of memory T cells. Foxo1 down-regulation is also associated with the up-regulation of co-inhibitory receptors by memory T cells and exhaustion in aged mice. Using adoptive transfer experiments, we show that the age-dependent down-regulation of Foxo1 in T cells is mediated by T-cell-extrinsic cues, including type 1 interferons. Taken together, our data suggest that type 1 interferon-induced Foxo1 down-regulation is likely to contribute significantly to T-cell dysfunction in aged mice

    Phenotypic and functional analysis of bovine peripheral blood dendritic before parturition by a novel purification methods

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    Dendritic cells (DCs) are specialized antigen presenting cells specializing in antigen uptake and processing, and play an important role in the innate and adaptive immune response. A subset of bovine peripheral blood DCs was identified as CD172a+/CD11c+/MHC (major histocompatibility complex) class II+ cells. Although DCs are identified at 0.1%?0.7% of peripheral blood mononuclear cells (PBMC), the phenotype and function of DCs remain poorly understood with regard to maintaining tolerance during the pregnancy. All cattle used in this study were 1 month before parturition. We have established a novel method for the purification of DCs from PBMC using magnetic?activated cell sorting, and purified the CD172a+/CD11c+ DCs, with high expression of MHC class II and CD40, at 84.8% purity. There were individual differences in the expressions of CD205 and co?stimulatory molecules CD80 and CD86 on DCs. There were positive correlations between expression of cytokine and co?stimulatory molecules in DCs, and the DCs maintained their immune tolerance, evidenced by their low expressions of the co?stimulatory molecules and cytokine production. These results suggest that before parturition a half of DCs may be immature and tend to maintain tolerance based on the low cytokine production, and the other DCs with high co?stimulatory molecules may already have the ability of modulating the T?cell linagepublishersversionPeer reviewe

    Consensus document for invasive coronary physiologic assessment in Asia-Pacific countries

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    Background: Currently, invasive physiologic assessment such as fractional flow reserve is widely used worldwide with different adoption rates around the globe. Patient characteristics and physician preferences often differ in the Asia-Pacific (APAC) region with respect to treatment strategy, techniques, lesion complexity, access to coronary physiology and imaging devices, as well as patient management. Thus, there is a need to construct a consensus document on recommendations for use of physiology-guided percutaneous coronary intervention (PCI) in APAC populations. This document serves as an overview of recommendations describing the best practices for APAC populations to achieve more consistent and optimal clinical outcomes.  Methods and Results: A comprehensive multiple-choice questionnaire was provided to 20 interven- tional cardiologists from 10 countries in the APAC region. Clinical evidence, tips and techniques, and clinical situations for the use of physiology-guided PCI in APAC were reviewed and used to propose key recommendations. There are suggestions to continue to develop evidence for lesion and patient types that will benefit from physiology, develop directions for future research in health economics and local data, develop appropriate use criteria in different countries, and emphasize the importance of education of all stakeholders. A consensus recommendation to enhance the penetration of invasive physiology-based therapy was to adopt the 5E approach: Evidence, Education, Expand hardware, Economics and Expert consensus.  Conclusions: This consensus document and recommendations support interventional fellows and cardiologists, hospital administrators, patients, and medical device companies to build confidence and encourage wider implementation of invasive coronary physiology-guided therapy in the APAC region.
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