512 research outputs found

    The HIV/AIDS Epidemic in Miami: Perspectives of Stakeholders and Frontline Providers

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    Background: Miami, Florida persists as an epicenter of HIV/AIDS nationally and has been more delayed than other areas with high HIV burden in implementing public health measures that mitigate transmission risk. These issues among other social and structural-level determinants have complicated progress in addressing HIV/AIDS in Miami. Purpose: The stagnated progress in improving HIV outcomes in Miami necessitated a more comprehensive understanding of the experiences and insights of stakeholders within the system. We used a stakeholder analysis approach to understand the complexity of driving factors and key challenges facing this HIV epidemic. Methods: A stakeholder analysis was conducted through 11 focus groups (64 participants) with front line workers working in non-profit, community-based agencies in Miami. The interview guide was designed to elicit a broad discussion on the social and intermediary determinants of HIV/AIDS, as well as the context surrounding barriers to treatment. Data were analyzed using qualitative software for thematic analysis. Results: Participants highlighted particular populations vulnerable to HIV/AIDS and insufficiently engaged in treatment, including immigrants and people who use drugs. Stigma surrounding HIV/AIDS as well as sexual orientation, mental health, and drug use was a noted persisting barrier. Participants expressed needs for more targeted outreach and education for both prevention and treatment. Numerous systemic gaps were identified as barriers to treatment engagement and retention. Other comorbidities and socioeconomic challenges, including criminal justice histories, housing instability and low educational attainment, also hamper HIV/AIDS management. Discussion: Through these discussions with stakeholders representing a diversity of voices, findings can inform comprehensive and coordinated strategies for curbing the HIV/AIDS epidemic in Miami. The development of prevention and treatment interventions should consider cultural contexts of health behaviors, multi-level stigma related to HIV/AIDS and other comorbid and socioeconomic challenges, and increased implementation of harm reduction programs such as PrEP delivery and syringe exchange programs

    The Mission Accessible Near-Earth Objects Survey: Four years of photometry

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    Over 4.5 years, the Mission Accessible Near-Earth Object Survey (MANOS) assembled 228 Near-Earth Object (NEO) lightcurves. We report rotational lightcurves for 82 NEOs, constraints on amplitudes and periods for 21 NEOs, lightcurves with no detected variability within the image signal to noise and length of our observing block for 30 NEOs, and 10 tumblers. We uncovered 2 ultra-rapid rotators with periods below 20s; 2016MA with a potential rotational periodicity of 18.4s, and 2017QG18_{18} rotating in 11.9s, and estimate the fraction of fast/ultra-rapid rotators undetected in our project plus the percentage of NEOs with a moderate/long periodicity undetectable during our typical observing blocks. We summarize the findings of a simple model of synthetic NEOs to infer the object morphologies distribution using the measured distribution of lightcurve amplitudes. This model suggests a uniform distribution of axis ratio can reproduce the observed sample. This suggests that the quantity of spherical NEOs (e.g., Bennu) is almost equivalent to the quantity of highly elongated objects (e.g., Itokawa), a result that can be directly tested thanks to shape models from Doppler delay radar imaging analysis. Finally, we fully characterized 2 NEOs as appropriate targets for a potential robotic/human mission: 2013YS2_{2} and 2014FA7_{7} due to their moderate spin periods and low Δv\Delta v.Comment: Accepted for Publication, The Astrophysical Journal Supplement Serie

    Reactivity of vanadium oxytrichloride with [beta]-diketones and diesters as precursors for vanadium nitride and carbide

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    Vanadium(V) oxytrichloride was reacted with 2,4-pentanedione, diethyl malonate, and diethyl succinate under inert conditions, forming compounds: dichloro(oxo)(2,4-pentanedione) vanadium(V) [1], dichloro(oxo)(diethyl malonate) vanadium(IV) [2] and dichloro(oxo)(diethyl succinate) vanadium(IV) [3]. Compounds 1–3 are coordinated to the vanadium centre through the two carbonyl oxygen atoms of the bidentate ligand. It was determined by X-ray crystallography that the structures of the resulting complexes were significantly different, resulting in a monomeric complex (1), a tetrameric ring (2) and a 1D coordination polymer (3). Following the synthesis and isolation of 1–3, they were tested as precursors for vanadium nitride and vanadium carbide by annealing under nitrogen and argon respectively at 1200 °C for 24 h. The resulting materials were characterised by: XRD, EDS, XPS and TEM

    Constitutive dimerization of glycoprotein VI (GPVI) in resting platelets is essential for binding to collagen and activation in flowing blood

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    The platelet collagen receptor glycoprotein VI (GPVI) has been suggested to function as a dimer, with increased affinity for collagen. Dissociation constants (K(d)) obtained by measuring recombinant GPVI binding to collagenous substrates showed that GPVI dimers bind with high affinity to tandem GPO (Gly-Pro-Hyp) sequences in collagen, whereas the markedly lower affinity of the monomer for all substrates implies that it is not the collagen-binding form of GPVI. Dimer binding required a high density of immobilized triple-helical (GPO)(10)-containing peptide, suggesting that the dimer binds multiple, discrete peptide helices. Differential inhibition of dimer binding by dimer-specific antibodies, m-Fab-F and 204-11 Fab, suggests that m-Fab-F binds at the collagen-binding site of the dimer, and 204-11 Fab binds to a discrete site. Flow cytometric quantitation indicated that GPVI dimers account for ~29% of total GPVI in resting platelets, whereas activation by either collagen-related peptide or thrombin increases the number of dimers to ~39 and ~44%, respectively. m-Fab-F inhibits both GPVI-dependent static platelet adhesion to collagen and thrombus formation on collagen under low and high shear, indicating that pre-existing dimeric GPVI is required for the initial interaction with collagen because affinity of the monomer is too low to support binding and that interaction through the dimer is essential for platelet activation. These GPVI dimers in resting circulating platelets will enable them to bind injury-exposed subendothelial collagen to initiate platelet activation. The GPVI-specific agonist collagen-related peptide or thrombin further increases the number of dimers, thereby providing a feedback mechanism for reinforcing binding to collagen and platelet activation
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