Publications by authors named "Kephart J"

Black men suffer disproportionately from prostate cancer (PCa) compared to men of other races and ethnicities. Comparing the molecular landscape of PCa among Black and White patients has the potential to identify targets for development of new precision medicine interventions. Herein, we conducted transcriptomic analysis of prostate tumors and paired tumor-adjacent normals from self-reported Black and White PCa patients and estimated patient genetic ancestry.

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This study investigates the electronic interactions and charge redistribution at the dopant-support interface using a Cu/CoSe cluster construct. Specifically, the redox cluster series [CuCoSeL] ([-Cu]; = 0, -1, -2, -3; L = PhPNTol, Ph = phenyl, Tol = -tolyl) spanning four distinct oxidation states is synthesized and characterized using a multitude of techniques, including multinuclear NMR, UV-vis, XANES, and X-ray crystallography. Structural investigations indicate that the clusters are isostructural and chiral, adopting a pseudo- symmetry.

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Article Synopsis
  • - Heatwaves in Latin America are expected to become more frequent, longer, and more intense by mid-century, with even greater increases under the high emissions scenario (RCP8.5) compared to the low emissions scenario (RCP2.6).
  • - The frequency of heatwaves may double across most of Latin America, leading to a significant increase in population exposure to extreme heat, projected to rise by three to ten times in Central and South America.
  • - Following a low emissions pathway (RCP2.6) could significantly reduce heatwave exposure—by 57% in Central America and 50% in South America—emphasizing the need for emissions control and sustainable practices to mitigate climate change impacts. *
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Climate hazards threaten the health and wellbeing of people living in urban areas. This study characterized reported climate hazards, adaptation action, and barriers to adaptation in 124 Latin American cities, and associations of climate hazards with urban social and built environment characteristics. We examined cities that responded to a global environmental disclosure system and that were included in the Urban Health in Latin America (SALURBAL) Project database.

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Article Synopsis
  • Climate change is causing more flooding, especially in cities in Latin American countries where people have less money.
  • The study looked at 276 cities and found that neighborhoods with lower education levels have a lot more flooding.
  • It's really important for leaders to focus on helping these neighborhoods deal with floods because people there are at higher risk.
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Directing groups guide substitution patterns in organic synthetic schemes, but little is known about pathways to control reactivity patterns, such as regioselectivity, in complex inorganic systems such as bioinorganic cofactors or extended surfaces. Interadsorbate effects are known to encode surface reactivity patterns in inorganic materials, modulating the location and binding strength of ligands. However, owing to limited experimental resolution into complex inorganic structures, there is little opportunity to resolve these effects on the atomic scale.

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Objective: Retrospective exposure to a higher number and prolonged duration of climate-related disasters could be positively associated with adolescent mental distress.

Methods: Person-level data came from 38,616 high-school students residing in 22 urban public-school districts in 14 states (U.S.

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Ambient air pollution is a health concern in Latin America given its large urban population exposed to levels above recommended guidelines. Yet no studies have examined the mortality impact of air pollutants in the region across a wide range of cities. We assessed whether short-term levels of fine particulate matter (PM) from modeled estimates, are associated with cardiovascular and respiratory mortality among adults in 337 cities from 9 Latin American countries.

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Background: Health research on ambient nitrogen dioxide (NO) is sparse in Latin America, despite the high prevalence of NO-associated respiratory diseases in the region. This study describes within-city distributions of ambient NO concentrations at high spatial resolution and urban characteristics associated with neighbourhood ambient NO in 326 Latin American cities.

Methods: We aggregated estimates of annual surface NO at 1 km spatial resolution for 2019, population counts, and urban characteristics compiled by the SALURBAL project to the neighbourhood level (ie, census tracts).

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Green vegetation may protect against heat-related death by improving thermal comfort. Few studies have investigated associations of green vegetation with heat-related mortality in Latin America or whether associations are modified by the spatial configuration of green vegetation. We used data from 323 Latin American cities and meta-regression models to estimate associations between city-level greenness, quantified using population-weighted normalized difference vegetation index values and modeled as three-level categorical terms, and excess deaths from heat (heat excess death fractions [heat EDFs]).

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Background: Exclusive clean fuel use is essential for realizing health and other benefits but is often unaffordable. Decreasing household-level fuel needs could make exclusive clean fuel use more affordable, but there is a lack of knowledge on the amount of fuel savings that could be achieved through fuel conservation behaviors relevant to rural settings in low- and middle-income countries.

Methods: Within a trial in Peru, we trained a random half of intervention participants, who had previously received a liquefied petroleum gas (LPG) stove and were purchasing their own fuel, on fuel conservation strategies.

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Here, we investigate the stereoelectronic requirements of a family of Fe/CoSe molecular clusters to achieve a Goldilocks regime of substrate affinity for the catalytic coupling of tosyl azide and -butyl isocyanide. The reactivity of a catalytically competent iron-nitrenoid intermediate, observed , is explored toward nitrene transfer and hydrogen-atom abstraction. The dual role of isocyanide, which, on the one hand, prevents catalyst degradation but, in large amounts, slows down reactivity, is exposed.

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Background: Health research on ambient nitrogen dioxide (NO) is sparse in Latin America, despite the high prevalence of NO-associated respiratory diseases in the region. This study describes within-city distributions of ambient NO concentrations at high spatial resolution and urban characteristics associated with neighborhood ambient NO in 326 Latin American cities.

Methods: We aggregated estimates of annual surface NO at 1 km spatial resolution for 2019, population counts, and urban characteristics compiled by the SALURBAL project to the neighborhood level (i.

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Article Synopsis
  • The study assessed whether providing 12 months of free liquefied petroleum gas (LPG) and behavioral support would encourage continued use and purchase after the free period ended.
  • 180 women participated, with half receiving free LPG while the other half served as a control group; measurements included stove usage and in-depth interviews to assess behavior change.
  • Results showed that the intervention group sustained high LPG usage (85.4% of days) post-free fuel period, but continued use was influenced by affordability, cooking habits, and access to LPG delivery services.
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Objective: Household air pollution (HAP) is a widespread environmental exposure worldwide. While several cleaner fuel interventions have been implemented to reduce personal exposures to HAP, it is unclear if cooking with cleaner fuels also affects the choice of meals and dietary intake.

Design: Individually randomised, open-label controlled trial of a HAP intervention.

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Background: In Latin America, where climate change and rapid urbanization converge, non-optimal ambient temperatures contribute to excess mortality. However, little is known about area-level characteristics that confer vulnerability to temperature-related mortality.

Objectives: Explore city-level socioeconomic and demographic characteristics associated with temperature-related mortality in Latin American cities.

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This study provides atomistic insights into the interface between a single-site catalyst and a transition metal chalcogenide support and reveals that peak catalytic activity occurs when edge/support redox cooperativity is maximized. A molecular platform MCoSe(PEt)(L) (-M, M = Cr, Mn, Fe, Co, Cu, and Zn) was designed in which the active site (M)/support (CoSe) interactions are interrogated by systematically probing the electronic and structural changes that occur as the identity of the metal varies. All 3d transition metal -M clusters display remarkable catalytic activity for coupling tosyl azide and -butyl isocyanide, with Mn and Co derivatives showing the fastest turnover in the series.

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Background: Extreme temperatures may lead to adverse pregnancy and birth outcomes, including low birthweight. Studies on the impact of temperature on birthweight have been inconclusive due to methodological challenges related to operationalizing temperature exposure, the definitions of exposure windows, accounting for gestational age, and a limited geographic scope.

Methods: We combined data on individual-level term live births (N≈15 million births) from urban areas in Brazil, Chile, and Mexico from 2010 to 2015 from the SALURBAL study (Urban Health in Latin America) with high-resolution daily air temperature data and computed average ambient temperature for every month of gestation for each newborn.

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Climate change and urbanization are rapidly increasing human exposure to extreme ambient temperatures, yet few studies have examined temperature and mortality in Latin America. We conducted a nonlinear, distributed-lag, longitudinal analysis of daily ambient temperatures and mortality among 326 Latin American cities between 2002 and 2015. We observed 15,431,532 deaths among ≈2.

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This study uncovers the interconnected reactivity of the three catalytically active sites of an atomically precise nanocluster Cr(py)CoSeL ((py), L = PhPNTol, Ph = phenyl, Tol = 4-tolyl). Catalytic and stoichiometric studies into tosyl azide activation and carbodiimide formation enabled the isolation and crystallographic characterization of key catalytically competent metal-imido intermediates, including the tris(imido) cluster (NTs), the catalytic resting state (NTs)(CNBu), and the site-differentiated mono(imido) cluster (NTs)(CNBu). In the stoichiometric regime, nitrene transfer proceeds via a stepwise mechanism, with the three active sites engaging sequentially to produce carbodiimide.

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Background: Household air pollution (HAP) from biomass fuel combustion remains a leading environmental risk factor for morbidity worldwide.

Objective: Measure the effect of liquefied petroleum gas (LPG) interventions on HAP exposures in Puno, Peru.

Methods: We conducted a 1-y randomized controlled trial followed by a 1-y pragmatic crossover trial in 180 women age 25-64 y.

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Background: In preclinical models of prostate cancer (PC), disulfiram (DSF) reduced tumor growth only when co-administered with copper (Cu), and Cu uptake in tumors is partially regulated by androgen-receptor signaling. However, prior trials of DSF in PC used DSF as monotherapy.

Objective: To assess the safety and efficacy of concurrent administration of DSF with Cu, we conducted a phase 1b clinical trial of patients with metastatic castration-resistant prostate cancer (mCRPC) receiving Cu with DSF.

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We demonstrate that allosteric effects and redox state changes can be harnessed to create a switch that selectively and reversibly regulates the coordination chemistry of a single site on the surface of a molecular cluster. This redox-switchable allostery is employed as a guiding force to assemble the molecular clusters ZnCoSeL' (L' = PhPN(H)Tol, Ph = phenyl, Tol = 4-tolyl) into materials of predetermined dimensionality (1- or 2-D) and to encode them with emissive properties. This work paves the path to program the assembly and function of inorganic clusters into stimuli-responsive, atomically precise materials.

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Article Synopsis
  • The study investigates how changes in population mobility at the subcity level affect COVID-19 incidence in various Latin American cities, highlighting the significance of mobility and its impact during the pandemic, especially where vaccine access is limited.
  • Using mobile phone location data and confirmed COVID-19 cases from March to August 2020, the research analyzed trends in mobility and infection rates across 1,031 subcity areas in five Latin American countries.
  • The findings indicate a significant correlation, showing that a one unit increase in mobility led to a 2.35 times increase in COVID-19 incidence, underscoring the importance of monitoring mobility patterns for public health interventions.
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