Fine particulate matter (PM2.5) air pollution exposure is the largest environmental health risk factor in the United States. Here, we link PM2.5 exposure to the human activities responsible for PM2.5 ...pollution. We use these results to explore “pollution inequity”: the difference between the environmental health damage caused by a racial–ethnic group and the damage that group experiences. We show that, in the United States, PM2.5 exposure is disproportionately caused by consumption of goods and services mainly by the non-Hispanic white majority, but disproportionately inhaled by black and Hispanic minorities. On average, non-Hispanic whites experience a “pollution advantage”: They experience ∼17% less air pollution exposure than is caused by their consumption. Blacks and Hispanics on average bear a “pollution burden” of 56% and 63% excess exposure, respectively, relative to the exposure caused by their consumption. The total disparity is caused as much by how much people consume as by how much pollution they breathe. Differences in the types of goods and services consumed by each group are less important. PM2.5 exposures declined ∼50% during 2002–2015 for all three racial–ethnic groups, but pollution inequity has remained high.
The increasing need for energy storage has been the motivation for intensive research in batteries with different chemistries in the recent past. Among the elements of the batteries, the salts and ...their solvent play an important role. In particular, the cathodic stability at low potential depends importantly on the choice of the cation, while the stability at high potentials is mainly due to oxidation of anions and the ion mobility and dissociation depend primarily on the delocalization of the anion, so that many attempts are made to find the optimum choice of both the cations and anions of the salts, and their solvents. Although lithium-based batteries are almost exclusively used today, efforts are currently made to explore batteries based on sodium, aluminum, magnesium, calcium, potassium. The purpose of the present work is to review the salts and solvents that have been proposed in these different batteries and discuss their properties and their ability to be used in the near future and in the next generation of batteries.
Interprofessional care is exhibited in outpatient oncology practices where practitioners from a myriad of specialties (e.g., oncology, nursing, pharmacy, health informatics and others) work ...collectively with patients to enhance therapeutic outcomes and minimize adverse effects. Historically, most ambulatory-based anticancer medication therapies have been administrated in infusion clinics or physician offices. Oral anticancer medications (OAMs) have become increasingly prevalent and preferred by patients for use in residential or other non-clinic settings. Self-administration of OAMs represents a significant shift in the management of cancer care and role responsibilities for patients and clinicians. While patients have a greater sense of empowerment and convenience when taking OAMs, adherence is a greater challenge than with intravenous therapies. This paper proposes use of a qualitative systems evaluation, based on theoretical frameworks for interdisciplinary team collaboration and systems science, to examine the social interactionism involved with the use of intravenous anticancer treatments and OAMs (as treatment technologies) by describing patient, organizational, and social systems considerations in communication, care, control, and context (i.e., Kaplan's 4Cs). This conceptualization can help the healthcare system prepare for substantial workforce changes in cancer management, including increased utilization of oncology pharmacists.
To the extent that pollution and population are spatially correlated, air quality modeling with coarse-resolution horizontal grids may systematically underpredict exposures and disparities in ...exposure among demographic groups (i.e., environmental injustice). We use InMAP, a reduced-complexity air pollution model, to quantify how estimates of year-2014 fine particulate matter (PM2.5) exposure in the United States vary with model spatial resolution, for a variable-resolution grid. We test five grids, with population-weighted average grid cell edge lengths ranging from 5.9 to 69 km. We find that model-estimated PM2.5 exposure, and exposure disparities among racial-ethnic groups, are lower with coarse grids than with fine grids: switching from our coarsest- to finest-resolution grid increases the calculated population-weighted average exposure by 27% (from 6.6 to 8.3 μg m–3) and causes the estimated difference in average exposure between minorities and whites to increase substantially (from 0.4 to 1.6 μg m–3). Across all grid resolutions, exposure disparities by race-ethnicity can be detected in every income category. Exposure disparities by income alone remain small relative to disparities by race-ethnicity, irrespective of resolution. These results demonstrate the importance of fine model spatial resolution for identifying and quantifying exposure disparity.
Racial-ethnic minorities in the United States are exposed to disproportionately high levels of ambient fine particulate air pollution (PM
), the largest environmental cause of human mortality. ...However, it is unknown which emission sources drive this disparity and whether differences exist by emission sector, geography, or demographics. Quantifying the PM
exposure caused by each emitter type, we show that nearly all major emission categories-consistently across states, urban and rural areas, income levels, and exposure levels-contribute to the systemic PM
exposure disparity experienced by people of color. We identify the most inequitable emission source types by state and city, thereby highlighting potential opportunities for addressing this persistent environmental inequity.
Lithium–sulfur batteries are of great interest owing to their high theoretical capacity of 1675 mA h g −1 and low cost. Their discharge mechanism is complicated and it is still a controversial issue. ...In the present work, in situ Raman spectroscopy is employed to investigate the poly-sulfide species in the sulfur cathode and in the electrolyte during the cycling of Li–S batteries. The aim is to understand the discharge mechanism and the influence of the electrolyte on the dissolution of sulfur and poly-sulfides. S 8 n− is identified as the main species in the high voltage plateau of discharge together with cycloocta S 8 , in the cell using 0.5 mol L −1 LiTFSI–PY 13 –FSI as the electrolyte. S 4 2− , S 2 2− and S 2− are detected soon after the low voltage plateau is reached. A discharge mechanism in the PY 13 –FSI is proposed based on the identified species which provides important information for improving and designing cathodes. Electrolytes of 0.5 mol L −1 LiTFSI–PY 13 –FSI and 1 mol L −1 LiTFSI–DOL–DME are used in studying the dissolution of sulfur and poly-sulfides. The results demonstrate that the same poly-sulfide species are present in the two electrolytes. However, the rates of poly-sulfide formation and diffusion to the anode are slow in the ionic liquid compared to those in the ether-based electrolyte due to different ionic mobilities of various species in the two electrolytes. These differences are evidenced by the observation of poly-sulfide species in the DOL–DME from the very beginning of cell assembly even before starting the discharge whereas their appearances, in the ionic liquid, are delayed and only found at the end of the high voltage plateau. Notably, the soluble elemental sulfur is clearly observed in the ionic liquid electrolyte during the first discharge in the high voltage region, which is very different from the DOL–DME system where the elemental sulfur is quickly reduced to poly-sulfides due to self-discharge reactions. In addition, the elemental sulfur is also detected near the lithium anode in DOL–DME at the end of charge, for the first time to our knowledge, which suggests that the degradation of lithium metal is caused by the multiple reactions of the lithium metal surface with soluble poly-sulfides and/or elemental sulfur.
A new optoelectronic oscillator (OEO) topology based on a class E analog fiber optic link is presented. This topology provides a high level of inherent opto-electronic conversion gain in the analog ...fiber optic link portion of the OEO thus eliminating the need for dedicated post-detector gain. The class E operation also allows for dual loop operation using a single optical detector and can provide good dc-RF efficiency. A proof-of-concept dual loop OEO was designed at 77 MHz and experimental results are reported that validate the proposed topology.
The MESFET as an optically sensitive microwave element in MMICs has attracted much attention. The theoretical modeling of the device, however, needs more consideration. The authors propose an ...analytical model for the illuminated MESFET, complete in that all major contributions to the optical response are considered. The dependence of the response on bias conditions, the wavelength and intensity of the optical input, and the particulars of device structure, are incorporated in the model. The importance of the internal photovoltaic effect, which has not been properly modeled previously, is emphasized. The novel theoretical model is verified by experimental results.< >
Described in this paper are the photoresponse characteristics of microwave transistors, both unipolar metal-semiconductor FETs (MESFETs) and modulation-doped FETs (MODFETs) and bipolar heterojunction ...bipolar transistors (HBTs). Investigation includes time- and frequency-domain measurements. For unipolar device FETs, the two dominant photodetection mechanisms, photoconductive and photovoltaic, are clearly identified within the same device for the first time. It is shown that even high-speed FETs are limited to a photonic bandwidth of a few megahertz, if photodetection and amplification are to be achieved simultaneously. In contrast, bipolar HBTs can provide optical gain up to the millimeter-wave range. It is shown that their bandwidth to a modulated optical input is closely related to the microwave bandwidth, and that parameters such as base-access resistance and base-emitter capacitance are critical to photoresponse optimization.
In recent years, the usefulness of the MESFET as an optically sensitive microwave element on MMIC's has generated much interest. A theoretical model for the device under steady illumination has been ...developed previously by the authors. This paper presents an extension of that model to include sinusoidally modulated illumination up to the microwave range. The dependence of the response on the bias conditions, the wavelength intensity and modulation frequency of the optical input, and the particulars of device structure are incorporated in the model. The importance of the internal photovoltaic effect, not properly accounted for in previous works, is emphasized. The theoretical model is validated by experimental results.< >
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