4,761 research outputs found
Substantial improvements not seen in health behaviors following corner store conversions in two Latino food swamps.
BackgroundThe effectiveness of food retail interventions is largely undetermined, yet substantial investments have been made to improve access to healthy foods in food deserts and swamps via grocery and corner store interventions. This study evaluated the effects of corner store conversions in East Los Angeles and Boyle Heights, California on perceived accessibility of healthy foods, perceptions of corner stores, store patronage, food purchasing, and eating behaviors.MethodsHousehold data (n = 1686) were collected at baseline and 12- to 24-months post-intervention among residents surrounding eight stores, three of which implemented a multi-faceted intervention and five of which were comparisons. Bivariate analyses and logistic and linear regressions were employed to assess differences in time, treatment, and the interaction between time and treatment to determine the effectiveness of this intervention.ResultsImprovements were found in perceived healthy food accessibility and perceptions of corner stores. No changes were found, however, in store patronage, purchasing, or consumption of fruits and vegetables.ConclusionsResults suggest limited effectiveness of food retail interventions on improving health behaviors. Future research should focus on other strategies to reduce community-level obesity
Effects Of Magnetic Drift Shell Splitting On Electron Diffusion In The Radiation Belts
Drift shell splitting in the presence of pitch angle scattering breaks all three adiabatic invariants of radiation belt electron motion and produces new diffusion terms that fully populate the diffusion tensor in the Fokker-Planck equation. The Radbelt Electron Model (REM) solves such a Fokker-Planck equation and is used to investigate the phase space density sources. Our simulation results and theoretical arguments suggest that drift shell splitting changes the phase space location of the source to smaller L shells, which typically reduces outer zone phase space density enhancements, and this reduction has a limit corresponding to two-dimensional local diffusion on a curved surface in the phase space
Cavity Design and Optimization for Organic Microcavity OLEDs
We report on detailed simulations of the emission from microcavity OLEDs consisting of widely used organic materials, n,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB) as a hole transport layer and tris (8-hydroxyquinoline) (Alq3) as emitting and electron transporting layer. The thick silver film was considered as a top mirror, while silver or copper films on quartz substrate were considered as bottom mirrors. The electroluminescence emission spectra, electric field distribution inside the device, carrier density and recombination rate were calculated as a function of the position of the emission layer, i.e. interface between NPB and Alq3. In order to achieve optimum emission from a microcavity OLED, it is necessary to align the position of the recombination region with the antinode of the standing wave inside the cavity. Once the optimum structure has been determined, the microcavity OLED devices were fabricated and characterized. The experimental results have been compared to the simulations and the influence of the emission region width and position on the performance of microcavity OLEDs was discussed
Measuring cognitive assessment and intervention burden in patients with acquired brain injured: Development of the "How Much is Too Much" questionnaire
Objective: To design and preliminarily test a questionnaire intended to measure patient treatment burden resulting from participation in cognitive assessments and interventions.
Methods: An expert consensus process was used to develop the concept of patient treatment burden and to determine the first set of questionnaire items and administration protocol. The pilot questionnaire was administered to 20 patients with mild to severe acquired brain injuries on completion of a 2-h or longer neuropsychological assessment. Following preliminary testing, the questionnaire was revised and re-evaluated by a second expert panel and content validity was assessed.
Results: Burden was defined as psychologically and/or physically aversive symptoms in response to cognitive assessment or intervention. The first questionnaire contained 21 items assigned to 3 categories: physical, cognitive, and emotional. Eightyfive percent of patients endorsed symptom level increases, with "tired/fatigued" the most frequently endorsed item (80% of patients). Instructions and test items were easily understood, and the questionnaire was quick to administer. Content validity ratio (CVR) of the revised questionnaire yielded 23 acceptable items and a subset met the highest CVR threshold (>0.78).
Conclusion: This patient-reported outcome will ultimately help patients give voice to aversive experiences, and help clinicians and researchers to monitor and adapt assessments/treatments appropriately. Future steps in development are described
Lorentz-CPT violation, radiative corrections and finite temperature
In this work we investigate the radiatively induced Chern-Simons-like terms
in four-dimensions at zero and finite temperature. We use the approach of
rationalizing the fermion propagator up to the leading order in the
CPT-violating coupling . In this approach, we have shown that although
the coefficient of Chern-Simons term can be found unambiguously in different
regularization schemes at zero or finite temperature, it remains undetermined.
We observe a correspondence among results obtained at finite and zero
temperature.Comment: To appear in JHEP, 10 pages, 1 eps figure, minor changes and
references adde
Structural Studies and Structure Activity Relationships for Novel Computationally Designed Non-nucleoside Inhibitors and Their Interactions With HIV-1 Reverse Transcriptase
Reverse transcriptase (RT) from the human immunodeficiency virus continues to be an attractive drug target for antiretroviral therapy. June 2022 will commemorate the 30th anniversary of the first Human Immunodeficiency Virus (HIV) RT crystal structure complex that was solved with non-nucleoside reverse transcriptase inhibitor nevirapine. The release of this structure opened opportunities for designing many families of non-nucleoside reverse transcriptase inhibitors (NNRTIs). In paying tribute to the first RT-nevirapine structure, we have developed several compound classes targeting the non-nucleoside inhibitor binding pocket of HIV RT. Extensive analysis of crystal structures of RT in complex with the compounds informed iterations of structure-based drug design. Structures of seven additional complexes were determined and analyzed to summarize key interactions with residues in the non-nucleoside inhibitor binding pocket (NNIBP) of RT. Additional insights comparing structures with antiviral data and results from molecular dynamics simulations elucidate key interactions and dynamics between the nucleotide and non-nucleoside binding sites.Fil: Frey, Kathleen M.. University of Yale; Estados UnidosFil: Bertoletti, Nicole. University of Yale; Estados UnidosFil: Chan, Albert H.. University of Yale; Estados UnidosFil: Ippolito, Joseph A.. University of Yale; Estados UnidosFil: Bollini, Mariela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. University of Yale; Estados UnidosFil: Spasov, Krasimir A.. University of Yale; Estados UnidosFil: Jorgensen, William L.. University of Yale; Estados UnidosFil: Anderson, Karen S.. University of Yale; Estados Unido
Optimized Longitudinal Monitoring of Stem Cell Grafts in Mouse Brain Using a Novel Bioluminescent/Near Infrared Fluorescent Fusion Reporter
Biodistribution and fate of transplanted stem cells via longitudinal monitoring has been successfully achieved in the last decade using optical imaging
Prediction of lethal and synthetically lethal knock-outs in regulatory networks
The complex interactions involved in regulation of a cell's function are
captured by its interaction graph. More often than not, detailed knowledge
about enhancing or suppressive regulatory influences and cooperative effects is
lacking and merely the presence or absence of directed interactions is known.
Here we investigate to which extent such reduced information allows to forecast
the effect of a knock-out or a combination of knock-outs. Specifically we ask
in how far the lethality of eliminating nodes may be predicted by their network
centrality, such as degree and betweenness, without knowing the function of the
system. The function is taken as the ability to reproduce a fixed point under a
discrete Boolean dynamics. We investigate two types of stochastically generated
networks: fully random networks and structures grown with a mechanism of node
duplication and subsequent divergence of interactions. On all networks we find
that the out-degree is a good predictor of the lethality of a single node
knock-out. For knock-outs of node pairs, the fraction of successors shared
between the two knocked-out nodes (out-overlap) is a good predictor of
synthetic lethality. Out-degree and out-overlap are locally defined and
computationally simple centrality measures that provide a predictive power
close to the optimal predictor.Comment: published version, 10 pages, 6 figures, 2 tables; supplement at
http://www.bioinf.uni-leipzig.de/publications/supplements/11-01
The PRE-Derived NMR Model of the 38.8-kDa Tri-Domain IsdH Protein from Staphylococcus aureus Suggests That It Adaptively Recognizes Human Hemoglobin
Staphylococcus aureus is a medically important bacterial pathogen that, during infections, acquires iron from human hemoglobin (Hb). It uses two closely related iron-regulated surface determinant (Isd) proteins to capture and extract the oxidized form of heme (hemin) from Hb, IsdH and IsdB. Both receptors rapidly extract hemin using a conserved tri-domain unit consisting of two NEAT (near iron transporter) domains connected by a helical linker domain. To gain insight into the mechanism of extraction, we used NMR to investigate the structure and dynamics of the 38.8-kDa tri-domain IsdH protein (IsdHN2N3, A326–D660 with a Y642A mutation that prevents hemin binding). The structure was modeled using long-range paramagnetic relaxation enhancement (PRE) distance restraints, dihedral angle, small-angle X-ray scattering, residual dipolar coupling and inter-domain NOE nuclear Overhauser effect data. The receptor adopts an extended conformation wherein the linker and N3 domains pack against each other via a hydrophobic interface. In contrast, the N2 domain contacts the linker domain via a hydrophilic interface and, based on NMR relaxation data, undergoes inter-domain motions enabling it to reorient with respect to the body of the protein. Ensemble calculations were used to estimate the range of N2 domain positions compatible with the PRE data. A comparison of the Hb-free and Hb-bound forms reveals that Hb binding alters the positioning of the N2 domain. We propose that binding occurs through a combination of conformational selection and induced-fit mechanisms that may promote hemin release from Hb by altering the position of its F helix
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