No abstract

No abstract

BackgroundExtreme heat is a public health challenge. The scarcity of directly comparable studies on the association of heat with morbidity and mortality and the inconsistent identification of threshold temperatures for severe impacts hampers the development of comprehensive strategies aimed at reducing adverse heat-health events.ObjectivesThis quantitative study was designed to link temperature with mortality and morbidity events in Maricopa County, Arizona, USA, with a focus on the summer season.MethodsUsing Poisson regression models that controlled for temporal confounders, we assessed daily temperature–health associations for a suite of mortality and morbidity events, diagnoses, and temperature metrics. Minimum risk temperatures, increasing risk temperatures, and excess risk temperatures were statistically identified to represent different “trigger points” at which heat-health intervention measures might be activated.ResultsWe found significant and consistent associations of high environmental temperature with all-cause mortality, cardiovascular mortality, heat-related mortality, and mortality resulting from conditions that are consequences of heat and dehydration. Hospitalizations and emergency department visits due to heat-related conditions and conditions associated with consequences of heat and dehydration were also strongly associated with high temperatures, and there were several times more of those events than there were deaths. For each temperature metric, we observed large contrasts in trigger points (up to 22°C) across multiple health events and diagnoses.ConclusionConsideration of multiple health events and diagnoses together with a comprehensive approach to identifying threshold temperatures revealed large differences in trigger points for possible interventions related to heat. Providing an array of heat trigger points applicable for different end-users may improve the public health response to a problem that is projected to worsen in the coming decades.CitationPetitti DB, Hondula DM, Yang S, Harlan SL, Chowell G. 2016. Multiple trigger points for quantifying heat-health impacts: new evidence from a hot climate. Environ Health Perspect 124:176–183; http://dx.doi.org/10.1289/ehp.1409119

Ti and Mg codoped Li 3 V 2À2x Ti x Mg x (PO 4 ) 3 (x = 0, 0.05, 0.10, 0.20, and 0.25) samples were prepared by a solÀgel method. The effects of Ti and Mg codoping on the physical and electrochemical characteristics of Li 3 V 2 (PO 4 ) 3 were investigated. Compared with the XRD pattern of the undoped sample, those of the Ti and Mg codoped samples have no extra reflections, which indicates that Ti and Mg enter the structure of Li 3 V 2 (PO 4 ) 3 . According to the results of chargeÀdischarge measurements, the initial capacity of Li 3 V 2À2x Ti x Mg x (PO 4 ) 3 at a low current density (0.2 C) decreases with increasing x. However, the discharge capacities at higher current densities (1 and 2 C) and the cycling stability are improved by a low amount of Ti and Mg codoping (x = 0.05), and moreover, EIS measurements indicate the lower charge transfer resistance of Li 3 V 1.9 Ti 0.05 Mg 0.05 (PO 4 ) 3 . The improved electrochemical performance of Li 3 V 1.9 Ti 0.05 Mg 0.05 (PO 4 ) 3 can be attributed to its higher structural stability and smaller particle size. When x is higher than 0.05, the charge transfer resistance increases with increasing x, which leads to their poor electrochemical performance.

In this study we characterized the relationship between temperature and mortality in central Arizona desert cities that have an extremely hot climate. Relationships between daily maximum apparent temperature (ATmax) and mortality for eight condition-specific causes and all-cause deaths were modeled for all residents and separately for males and females ages <65 and ≥65 during the months May–October for years 2000–2008. The most robust relationship was between ATmax on day of death and mortality from direct exposure to high environmental heat. For this condition-specific cause of death, the heat thresholds in all gender and age groups (ATmax = 90–97 °F; 32.2‒36.1 °C) were below local median seasonal temperatures in the study period (ATmax = 99.5 °F; 37.5 °C). Heat threshold was defined as ATmax at which the mortality ratio begins an exponential upward trend. Thresholds were identified in younger and older females for cardiac disease/stroke mortality (ATmax = 106 and 108 °F; 41.1 and 42.2 °C) with a one-day lag. Thresholds were also identified for mortality from respiratory diseases in older people (ATmax = 109 °F; 42.8 °C) and for all-cause mortality in females (ATmax = 107 °F; 41.7 °C) and males <65 years (ATmax = 102 °F; 38.9 °C). Heat-related mortality in a region that has already made some adaptations to predictable periods of extremely high temperatures suggests that more extensive and targeted heat-adaptation plans for climate change are needed in cities worldwide.

We present Monte Carlo simulations of thermal, structural, and dynamic properties of a 27-segment lattice model protein adsorbed to a solid surface. The protein consists of a sequence of A and B segments whose order and topological contact energy values are chosen so that a unique (3x3x3 cubic) folded state occurs in the absence of an adsorbing surface [E. I. Shakhnovich and M. Gutin, Proc. Natl. Acad. Sci. USA 90, 7195 (1993)]. The surface consists of a plane of sites that interact either (i) equally with all contacting protein segments (an equal affinity surface) or (ii) more strongly with type A contacting segments (an A affinity surface). For both surfaces, we find the conformational change of an initially folded protein to begin with a continuous transition to a structure where all segments contact the surface. This is followed by a partial refolding to a low energy state; this step is continuous and results in full surface contact for the equal affinity surface and is activated and results in significant loss of surface contact for the A affinity surface. We also observe a lesser (greater) degree of average surface contact in the equal (A) affinity surface with an increase in temperature.

Rational design of controllable drug release systems is important for tumor treatments due to the nonspecific toxicity of many chemotherapeutics. Herein, laser or light responsive pharmaceutical delivery nanoparticles are designed, by taking the advantages of redox responsive selenium (Se) substituted polymer as shell and photosensitive porphyrin zirconium metal–organic frameworks (MOF) as core. In detail, redox cleavable di‐(1‐hydroxylundecyl) selenide (DH‐Se), biocompatible poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) are randomly polymerized to form poly(DH‐Se/PEG/PPG urethane), which is used to coat the reactive oxygen species' (ROS) producible porous porphyrin zirconium metal organization formulation (PCN‐224 MOF) to form the final poly(DH‐Se/PEG/PPG urethane)@MOF shell–core nanoparticle with spherical shape by emulsion approach. Interestingly, poly(DH‐Se/PEG/PPG urethane)@MOF nanoparticles with loading of chemotherapeutic doxorubicin (DOX) experience a fast and controllable release, which can realize the combination of chemotherapy and photodynamic therapy upon irradiation with laser light, due to the light‐triggered ROS production by MOF which further causes the cleavage of poly(DH‐Se/PEG/PPG urethane) polymer chain and the release of encapsulated DOX. To the best of the authors' knowledge, this is the first design of utilizing MOF and selenium substituted polymer as controllable drug release carriers, which might be beneficial for precise chemotherapy and photodynamic therapy combination.

No abstract