2,341 research outputs found

    Using an external exposome framework to examine pregnancy-related morbidities and mortalities: Implications for health disparities research

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    © 2015 by the authors; licensee MDPI, Basel, Switzerland. Objective: We have conducted a study to assess the role of environment on the burden of maternal morbidities and mortalities among women using an external exposome approach for the purpose of developing targeted public health interventions to decrease disparities. Methods: We identified counties in the 48 contiguous USA where observed low birthweight (LBW) rates were higher than expected during a five-year study period. The identification was conducted using a retrospective space-time analysis scan for statistically significant clusters with high or low rates by a Discrete Poisson Model. Results: We observed statistically significant associations of LBW rate with a set of predictive variables. However, in one of the two spatiotemporal models we discovered LBW to be associated with five predictive variables (teen birth rate, adult obesity, uninsured adults, physically unhealthy days, and percent of adults who smoke) in two counties situated in Alabama after adjusting for location changes. Counties with higher than expected LBW rates were similarly associated with two environmental variables (ozone and fine particulate matter). Conclusions: The county-level predictive measures of LBW offer new insights into spatiotemporal patterns relative to key contributory factors. An external framework provides a promising place-based approach for identifying “hotspots” with implications for designing targeted interventions and control measures to reduce and eliminate health disparities

    The tyrosine kinase FER is responsible for the capacitation-associated increase in tyrosine phosphorylation in murine sperm

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    Sperm capacitation is required for fertilization. At the molecular level, this process is associated with fast activation of protein kinase A. Downstream of this event, capacitating conditions lead to an increase in tyrosine phosphorylation. The identity of the tyrosine kinase(s) mediating this process has not been conclusively demonstrated. Recent experiments using stallion and human sperm have suggested a role for PYK2 based on the use of small molecule inhibitors directed against this kinase. However, crucially, loss-of-function experiments have not been reported. Here, we used both pharmacological inhibitors and genetically modified mice models to investigate the identity of the tyrosine kinase(s) mediating the increase in tyrosine phosphorylation in mouse sperm. Similar to stallion and human, PF431396 blocks the capacitation-associated increase in tyrosine phosphorylation. Yet, sperm from Pyk2(-/-) mice displayed a normal increase in tyrosine phosphorylation, implying that PYK2 is not responsible for this phosphorylation process. Here, we show that PF431396 can also inhibit FER, a tyrosine kinase known to be present in sperm. Sperm from mice targeted with a kinase-inactivating mutation in Fer failed to undergo capacitation-associated increases in tyrosine phosphorylation. Although these mice are fertile, their sperm displayed a reduced ability to fertilize metaphase II-arrested eggs in vitro.Fil: Alvau, Antonio. University of Massachussets; Estados UnidosFil: Battistone, Maria Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Gervasi, Maria Gracia. University of Massachussets; Estados UnidosFil: Navarrete, Felipe A.. University of Massachussets; Estados UnidosFil: Xu, Xinran. State University of Colorado - Fort Collins; Estados UnidosFil: Sánchez Cárdenas, Claudia. Universidad Nacional Autónoma de México. Instituto de Biotecnología; MéxicoFil: De la Vega Beltran, José Luis. Universidad Nacional Autónoma de México. Instituto de Biotecnología; MéxicoFil: Da Ros, Vanina Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Greer, Peter. Queens University; CanadáFil: Darszon, Alberto. Universidad Nacional Autónoma de México. Instituto de Biotecnología; MéxicoFil: Krapf, Diego. State University of Colorado - Fort Collins; Estados UnidosFil: Salicioni, Ana María. University of Massachussets; Estados UnidosFil: Cuasnicu, Patricia Sara. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Visconti, Pablo E.. University of Massachussets; Estados Unido

    Swift J2058.4+0516: Discovery of a Possible Second Relativistic Tidal Disruption Flare?

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    We report the discovery by the Swift hard X-ray monitor of the transient source Swift J2058.4+0516 (Sw J2058+05). Our multi-wavelength follow-up campaign uncovered a long-lived (duration >~ months), luminous X-ray (L_X,iso ~ 3 x 10^47 erg s^-1) and radio (nu L_nu,iso ~ 10^42 erg s^-1) counterpart. The associated optical emission, however, from which we measure a redshift of 1.1853, is relatively faint, and this is not due to a large amount of dust extinction in the host galaxy. Based on numerous similarities with the recently discovered GRB 110328A / Swift J164449.3+573451 (Sw J1644+57), we suggest that Sw J2058+05 may be the second member of a new class of relativistic outbursts resulting from the tidal disruption of a star by a supermassive black hole. If so, the relative rarity of these sources (compared with the expected rate of tidal disruptions) implies that either these outflows are extremely narrowly collimated (theta < 1 degree), or only a small fraction of tidal disruptions generate relativistic ejecta. Analogous to the case of long-duration gamma-ray bursts and core-collapse supernovae, we speculate that rapid spin of the black hole may be a necessary condition to generate the relativistic component. Alternatively, if powered by gas accretion (i.e., an active galactic nucleus [AGN]), Sw J2058+05 would seem to represent a new mode of variability in these sources, as the observed properties appear largely inconsistent with known classes of AGNs capable of generating relativistic jets (blazars, narrow-line Seyfert 1 galaxies).Comment: Minor typos correcte

    Upper-Room Ultraviolet Light and Negative Air Ionization to Prevent Tuberculosis Transmission

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    Background Institutional tuberculosis (TB) transmission is an important public health problem highlighted by the HIV/AIDS pandemic and the emergence of multidrug- and extensively drug-resistant TB. Effective TB infection control measures are urgently needed. We evaluated the efficacy of upper-room ultraviolet (UV) lights and negative air ionization for preventing airborne TB transmission using a guinea pig air-sampling model to measure the TB infectiousness of ward air. Methods and Findings For 535 consecutive days, exhaust air from an HIV-TB ward in Lima, Perú, was passed through three guinea pig air-sampling enclosures each housing approximately 150 guinea pigs, using a 2-d cycle. On UV-off days, ward air passed in parallel through a control animal enclosure and a similar enclosure containing negative ionizers. On UV-on days, UV lights and mixing fans were turned on in the ward, and a third animal enclosure alone received ward air. TB infection in guinea pigs was defined by monthly tuberculin skin tests. All guinea pigs underwent autopsy to test for TB disease, defined by characteristic autopsy changes or by the culture of Mycobacterium tuberculosis from organs. 35% (106/304) of guinea pigs in the control group developed TB infection, and this was reduced to 14% (43/303) by ionizers, and to 9.5% (29/307) by UV lights (both p < 0.0001 compared with the control group). TB disease was confirmed in 8.6% (26/304) of control group animals, and this was reduced to 4.3% (13/303) by ionizers, and to 3.6% (11/307) by UV lights (both p < 0.03 compared with the control group). Time-to-event analysis demonstrated that TB infection was prevented by ionizers (log-rank 27; p < 0.0001) and by UV lights (log-rank 46; p < 0.0001). Time-to-event analysis also demonstrated that TB disease was prevented by ionizers (log-rank 3.7; p = 0.055) and by UV lights (log-rank 5.4; p = 0.02). An alternative analysis using an airborne infection model demonstrated that ionizers prevented 60% of TB infection and 51% of TB disease, and that UV lights prevented 70% of TB infection and 54% of TB disease. In all analysis strategies, UV lights tended to be more protective than ionizers. Conclusions Upper-room UV lights and negative air ionization each prevented most airborne TB transmission detectable by guinea pig air sampling. Provided there is adequate mixing of room air, upper-room UV light is an effective, low-cost intervention for use in TB infection control in high-risk clinical settings

    A novel cell-free mitochondrial fusion assay amenable for high-throughput screenings of fusion modulators

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    Abstract Background Mitochondria are highly dynamic organelles whose morphology and position within the cell is tightly coupled to metabolic function. There is a limited list of essential proteins that regulate mitochondrial morphology and the mechanisms that govern mitochondrial dynamics are poorly understood. However, recent evidence indicates that the core machinery that governs mitochondrial dynamics is linked within complex intracellular signalling cascades, including apoptotic pathways, cell cycle transitions and nuclear factor kappa B activation. Given the emerging importance of mitochondrial plasticity in cell signalling pathways and metabolism, it is essential that we develop tools to quantitatively analyse the processes of fission and fusion. In terms of mitochondrial fusion, the field currently relies upon on semi-quantitative assays which, even under optimal conditions, are labour-intensive, low-throughput and require complex imaging techniques. Results In order to overcome these technical limitations, we have developed a new, highly quantitative cell-free assay for mitochondrial fusion in mammalian cells. This assay system has allowed us to establish the energetic requirements for mitochondrial fusion. In addition, our data reveal a dependence on active protein phosphorylation for mitochondrial fusion, confirming emerging evidence that mitochondrial fusion is tightly integrated within the global cellular response to signaling events. Indeed, we have shown that cytosol derived from cells stimulated with different triggers either enhance or inhibit the cell-free fusion reaction. Conclusions The adaptation of this system to high-throughput analysis will provide an unprecedented opportunity to identify and characterize novel regulatory factors. In addition, it provides a framework for a detailed mechanistic analysis of the process of mitochondrial fusion and the various axis of regulation that impinge upon this process in a wide range of cellular conditions. See Commentary: http://www.biomedcentral.com/1741-7007/8/9

    GABA signalling modulates plant growth by directly regulating the activity of plant-specific anion transporters

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    The non-protein amino acid, gamma-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to biotic and abiotic stress, and regulates plant growth. Until now it was not known whether GABA exerts its effects in plants through the regulation of carbon metabolism or via an unidentified signalling pathway. Here, we demonstrate that anion flux through plant aluminium-activated malate transporter (ALMT) proteins is activated by anions and negatively regulated by GABA. Site-directed mutagenesis of selected amino acids within ALMT proteins abolishes GABA efficacy but does not alter other transport properties. GABA modulation of ALMT activity results in altered root growth and altered root tolerance to alkaline pH, acid pH and aluminium ions. We propose that GABA exerts its multiple physiological effects in plants via ALMT, including the regulation of pollen tube and root growth, and that GABA can finally be considered a legitimate signalling molecule in both the plant and animal kingdoms.Australian Research Council; Waite Research Institute grants: (FT130100709, DP130104205, CE140100008); Fundação para a Ciência e Tecnologia grant: (PTDC/BEX-BCM/0376/2012); University of Maryland.info:eu-repo/semantics/publishedVersio

    Evaluating 'Prefer not to say' Around Sensitive Disclosures

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    As people's offline and online lives become increasingly entwined, the sensitivity of personal information disclosed online is increasing. Disclosures often occur through structured disclosure fields (e.g., drop-down lists). Prior research suggests these fields may limit privacy, with non-disclosing users being presumed to be hiding undesirable information. We investigated this around HIV status disclosure in online dating apps used by men who have sex with men. Our online study asked participants (N=183) to rate profiles where HIV status was either disclosed or undisclosed. We tested three designs for displaying undisclosed fields. Visibility of undisclosed fields had a significant effect on the way profiles were rated, and other profile information (e.g., ethnicity) could affect inferences that develop around undisclosed information. Our research highlights complexities around designing for non-disclosure and questions the voluntary nature of these fields. Further work is outlined to ensure disclosure control is appropriately implemented around online sensitive information disclosures

    Water Formation Reaction under Interfacial Confinement: Al0.25Si0.75O2 on O-Ru(0001)

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    Confined nanosized spaces at the interface between a metal and a seemingly inert material, such as a silicate, have recently been shown to influence the chemistry at the metal surface. In prior work, we observed that a bilayer (BL) silica on Ru(0001) can change the reaction pathway of the water formation reaction (WFR) near room temperature when compared to the bare metal. In this work, we looked at the effect of doping the silicate with Al, resulting in a stoichiometry of AlSiO . We investigated the kinetics of WFR at elevated H pressures and various temperatures under interfacial confinement using ambient pressure X-ray photoelectron spectroscopy. The apparent activation energy was lower than that on bare Ru(0001) but higher than that on the BL-silica/Ru(0001). The apparent reaction order with respect to H was also determined. The increased residence time of water at the surface, resulting from the presence of the BL-aluminosilicate (and its subsequent electrostatic stabilization), favors the so-called disproportionation reaction pathway (*HO + *O ↔ 2 *OH), but with a higher energy barrier than for pure BL-silica.Research was carried out in part at the 23-ID-2 (IOS) beamline of the National Synchrotron Light Source II and the Center for Functional Nanomaterials, which are U.S. DOE Office of Science Facilities, and the Scientific Data and Computing Center, a component of the Computational Science Initiative, at Brookhaven National Laboratory under Contract No. DE-SC0012704. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. J.C. thanks the Spanish Ministry of Science, Innovation and Universities for a “Severo Ochoa” grant (BES-2015-075748) through “Severo Ochoa” Excellence Programme (SEV-2016-0683). Z.D. is supported by ACS PRF grant #61059-ND5
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