3,337 research outputs found
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Grindr Users Take More Risks, but Are More Open to Human Immunodeficiency Virus (HIV) Pre-exposure Prophylaxis: Could This Dating App Provide a Platform for HIV Prevention Outreach?
BackgroundTechnology has changed the way that men who have sex with men (MSM) seek sex. More than 60% of MSM in the United States use the internet and/or smartphone-based geospatial networking apps to find sex partners. We correlated use of the most popular app (Grindr) with sexual risk and prevention behavior among MSM.MethodsA nested cohort study was conducted between September 2018 and June 2019 among MSM receiving community-based human immunodeficiency virus (HIV) and sexually transmitted infection (STI) screening in central San Diego. During the testing encounter, participants were surveyed for demographics, substance use, risk behavior (previous 3 months), HIV pre-exposure prophylaxis (PrEP) use, and Grindr usage. Participants who tested negative for HIV and who were not on PrEP were offered immediate PrEP.ResultsThe study included 1256 MSM, 1090 of whom (86.8%) were not taking PrEP. Overall, 580 of 1256 (46%) participants indicated that they used Grindr in the previous 7 days. Grindr users reported significantly higher risk behavior (greater number of male partners and condomless sex) and were more likely to test positive for chlamydia or gonorrhea (8.6% vs 4.7% of nonusers; P = .005). Grindr users were also more likely to be on PrEP (18.7% vs 8.7% of nonusers; P < .001) and had fewer newly diagnosed HIV infections (9 vs 26 among nonusers; P = .014). Grindr users were also nearly twice as likely as nonusers to initiate PrEP (24.6% vs 14%; P < .001).ConclusionsGiven the higher risk behavior and greater acceptance of PrEP among MSM who used Grindr, Grindr may provide a useful platform to promote HIV and STI testing and increase PrEP uptake
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Epidemic dynamics of respiratory syncytial virus in current and future climates.
A key question for infectious disease dynamics is the impact of the climate on future burden. Here, we evaluate the climate drivers of respiratory syncytial virus (RSV), an important determinant of disease in young children. We combine a dataset of county-level observations from the US with state-level observations from Mexico, spanning much of the global range of climatological conditions. Using a combination of nonlinear epidemic models with statistical techniques, we find consistent patterns of climate drivers at a continental scale explaining latitudinal differences in the dynamics and timing of local epidemics. Strikingly, estimated effects of precipitation and humidity on transmission mirror prior results for influenza. We couple our model with projections for future climate, to show that temperature-driven increases to humidity may lead to a northward shift in the dynamic patterns observed and that the likelihood of severe outbreaks of RSV hinges on projections for extreme rainfall
Trimethylsilyl tag for probing protein-ligand interactions by NMR
Protein-ligand titrations can readily be monitored with a trimethylsilyl (TMS) tag. Owing to the intensity, narrow line shape and unique chemical shift of a TMS group, dissociation constants can be determined from straightforward 1D 1H-NMR spectra not only in the fast but also in the slow exchange limit. The tag is easily attached to cysteine residues and a sensitive reporter of ligand binding also at sites where it does not interfere with ligand binding or catalytic efficiency of the target protein. Its utility is demonstrated for the Zika virus NS2B-NS3 protease and the human prolyl isomerase FK506 binding protein.C.N. and G.O. thank the Alexander von Humboldt Foundation for a
Feodor Lynen Fellowship and the Australian Research Council for a
Laureate Fellowship, respectively. Financial project support by the
Australian Research Council, the Austrian Science Fund (FWF) (DK
Molecular Enzymology W901 to K.Z.) and by NAWI Graz is gratefully
acknowledged
Approximate and exact nodes of fermionic wavefunctions: coordinate transformations and topologies
A study of fermion nodes for spin-polarized states of a few-electron ions and
molecules with one-particle orbitals is presented. We find exact nodes
for some cases of two electron atomic and molecular states and also the first
exact node for the three-electron atomic system in state using
appropriate coordinate maps and wavefunction symmetries. We analyze the cases
of nodes for larger number of electrons in the Hartree-Fock approximation and
for some cases we find transformations for projecting the high-dimensional node
manifolds into 3D space. The node topologies and other properties are studied
using these projections. We also propose a general coordinate transformation as
an extension of Feynman-Cohen backflow coordinates to both simplify the nodal
description and as a new variational freedom for quantum Monte Carlo trial
wavefunctions.Comment: 7 pages, 7 figure
Electrically Conductive Photoluminescent Porphyrin Phosphonate Metal-Organic Frameworks
Herein, the design and synthesis of a highly photoluminescent and electrically conductive metal–organic framework [Zn{Cu-p-H6TPPA}]⋅2 [(CH3)2NH] (designated as GTUB3), which is constructed using the 5,10,15,20-tetrakis [p-phenylphosphonic acid] porphyrin (p-H8TPPA) organic linker, is reported. The bandgap of GTUB3 is measured to be 1.45 and 1.48 eV using diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy, respectively. The PL decay measurement yields a charge carrier lifetime of 40.6 ns. Impedance and DC measurements yield average electrical conductivities of 0.03 and 4 S m−1, respectively, making GTUB3 a rare example of an electrically conductive 3D metal–organic framework. Thermogravimetric analysis reveals that the organic components of GTUB3 are stable up to 400 °C. Finally, its specific surface area and pore volume are calculated to be 622 m2 g−1 and 0.43 cm3 g−1, respectively, using grand canonical Monte Carlo. Owing to its porosity and high electrical conductivity, GTUB3 may be used as a low-cost electrode material in next generation of supercapacitors, while its low bandgap and high photoluminescence make it a promising material for optoelectronic applications
Translation and validation of the Structured Interview for Prodromal Syndromes (SIPS) to Portuguese
Scaffold-free bioprinting of mesenchymal stem cells using the Regenova printer: Spheroid characterization and osteogenic differentiation
Limitations in scaffold material properties, such as sub-optimal degradation time, highlight the need for alternative approaches to engineer de novo tissues. One emerging solution for fabricating tissue constructs is scaffold-free tissue engineering. To facilitate this approach, three-dimensional (3D) bioprinting technology (Regenova Bio 3D Printer) has been developed to construct complex geometric shapes from discrete cellular spheroids without exogenous scaffolds. Optimizing spheroid fabrication and characterizing cellular behavior in the spheroid environment are important first steps prior to printing larger constructs. Here, we characterized spheroids of immortalized mouse bone marrow stromal cells (BMSCs) that were differentiated to the osteogenic lineage.
Immortalized BMSCs were seeded in low attachment 96-well plates in various numbers to generate self-aggregated spheroids either under the force of gravity or centrifugation. Cells were cultured in control or osteogenic media for up to 28 days. Spheroid diameter, roundness and smoothness were measured. Cell viability, DNA content and alkaline phosphatase activity were assessed at multiple time points. Additionally, expression of osteogenic markers was determined using real time qPCR.
Spheroids formed under gravity with 20 K, 30 K and 40 K cells had average diameters of 498.5 ± 8.3 μm, 580.0 ± 32.9 μm and 639.2 ± 54.0 μm, respectively, while those formed under 300G centrifugation with the same numbers of cells had average diameters of 362.3 ± 3.5 μm, 433.1 ± 6.4 μm and 491.2 ± 8.0 μm. Spheroids formed via centrifugation were superior to those formed by gravity, as evidenced by better roundness and smoothness and double the retention of DNA (cellular) content. Cells in spheroids exhibited a robust osteogenic response to the differentiation medium, including higher mRNA expression of alkaline phosphatase, collagen type I, and osteocalcin than those cultured in control medium, as well as greater alkaline phosphatase activity. The optimal spheroid fabrication technique from this study was to aggregate 40 K cells under 150–300G centrifugation. In future investigations, these spheroids will be 3D printed into larger tissue constructs
Incoherent electronic band states in Mn substituted BaFeAs
Chemical substitution is commonly used to explore new ground states in
materials, yet the role of disorder is often overlooked. In Mn-substituted
BaFeAs (MnBFA), superconductivity (SC) is absent, despite being
observed for nominal hole-doped phases. Instead, a glassy magnetic phase
emerges, associated with the Mn local spins. In this work, we present a
comprehensive investigation of the electronic structure of MnBFA using
angle-resolved photoemission spectroscopy (ARPES). We find that Mn causes
electron pockets to shrink, disrupting the nesting condition in MnBFA. Notably,
we propose that electronic disorder, along with magnetic scattering, primarily
contributes to suppressing the itinerant magnetic order in MnBFA. This finding
connects the MnBFA electronic band structure properties to the glassy magnetic
behavior observed in these materials and suggests that SC is absent because of
the collective magnetic impurity behavior that scatters the Fe-derived
excitations. Moreover, we suggest that Mn tunes MnBFA to a phase in between the
correlated metal in BaFeAs and the Hund insulator phase in
BaMnAs.Comment: main 7 pages, 3 figures + supp 5 pages, 5 figure
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