2,735 research outputs found

    Chirality Dependence of the KK-Momentum Dark Excitons in Carbon Nanotubes

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    Using a collection of twelve semiconducting carbon nanotube samples, each highly enriched in a single chirality, we study the chirality dependence of the KK-momentum dark singlet exciton using phonon sideband optical spectroscopy. Measurements of bright absorptive and emissive sidebands of this finite momentum exciton identify its energy as 20 - 38 meV above the bright singlet exciton, a separation that exhibits systematic dependencies on tube diameter, 2n+m2n+m family, and semiconducting type. We present calculations that explain how chiral angle dependence in this energy separation relates to the Coulomb exchange interaction, and elaborate the dominance of the KA1′K_{A_1'} phonon sidebands over the zone-center phonon sidebands over a wide range of chiralities. The Kataura plot arising from these data is qualitatively well described by theory, but the energy separation between the sidebands shows a larger chiral dependence than predicted. This latter observation may indicate a larger dispersion for the associated phonon near the KK point than expected from finite distance force modeling.Comment: 24 pages, 12 figures, 1 table; slight title change, Figures 1 and 11 added, reference added, presentation improved throughout documen

    Renoprotection with SGLT2 inhibitors in type 2 diabetes over a spectrum of cardiovascular and renal risk

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    Approximately half of all patients with type 2 diabetes (T2D) develop a certain degree of renal impairment. In many of them, chronic kidney disease (CKD) progresses over time, eventually leading to end-stage kidney disease (ESKD) requiring dialysis and conveying a substantially increased risk of cardiovascular morbidity and mortality. Even with widespread use of renin–angiotensin system blockers and tight glycemic control, a substantial residual risk of nephropathy progression remains. Recent cardiovascular outcomes trials investigating sodium–glucose cotransporter 2 (SGLT2) inhibitors have suggested that these therapies have renoprotective effects distinct from their glucose-lowering action, including the potential to reduce the rates of ESKD and acute kidney injury. Although patients in most cardiovascular outcomes trials had higher prevalence of existing cardiovascular disease compared with those normally seen in clinical practice, the proportion of patients with renal impairment was similar to that observed in a real-world context. Patient cardiovascular risk profiles did not relevantly impact the renoprotective benefits observed in these studies. Benefits were observed in patients across a spectrum of renal risk, but were evident also in those without renal damage, suggesting a role for SGLT2 inhibition in the prevention of CKD in people with T2D. In addition, recent studies such as CREDENCE and DAPA-CKD offer a greater insight into the renoprotective effects of SGLT2 inhibitors in patients with moderate-to-severe CKD. This review outlines the evidence that SGLT2 inhibitors may prevent the development of CKD and prevent and delay the worsening of CKD in people with T2D at different levels of renal risk

    Dust Dispersion Modeling For Opencast Mines

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    Mining operations generates substantial quantities of airborne respirable dust, which leads to the development of lung disease in mine workers. Coal worker's pneumoconiosis and silicosis are lung diseases that have adversely impacted the health of thousands of mine workers. The increasing trend of opencast mining leads to release of huge amount of dust. These air borne dust particles, generally below 100 micron in size, are environmentally nuisance and cause health hazards as an ill effect of mining activities. Opencast extraction activities like drilling, blasting, material handling and transport are a potential source of air pollution. Therefore, a detailed study on emission sources and quantification of pollutant concentration by means of dispersion modeling is required to access the environmental impact of a opencast mine. On the basis of the predicted increments to air pollutant concentrations, an effective mitigation and environmental plan can be devised for sensitive areas. In the present study, Air quality modeling has been attempted using AERMOD. Line source & Volume source modeling has been carried out for haul road and open pit respectively. From the modeling exercise, dust concentrations at certain receptor locations have been predicted and it was found that the resultant SPM level at these locations will remain within the NAAQS norms

    Cardiovascular protection with sodium-glucose co-transporter-2 inhibitors in type 2 diabetes: Does it apply to all patients?

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    Patients with type 2 diabetes (T2D) are at an increased risk of cardiovascular disease (CVD). Cardiovascular risk in these patients should be considered as a continuum, and comprehensive treatment strategies should aim to target multiple disease risk factors. Large-scale clinical trials of sodium-glucose co-transporter-2 (SGLT2) inhibitors have shown an impact on cardiovascular outcomes, including heart failure hospitalization and cardiovascular death, which appears to be independent of their glucose-lowering efficacy. Reductions in major cardiovascular events appear to be greatest in patients with established CVD, particularly those with prior myocardial infarction, but are independent of heart failure or renal risk. Most large-scale trials of SGLT2 inhibitors predominantly include patients with T2D with pre-existing CVD and high cardiovascular risk at baseline, limiting their applicability to patients typically observed in clinical practice. Real-world evidence from observational studies suggests that there might also be beneficial effects of SGLT2 inhibitors on heart failure hospitalization and all-cause mortality in various cohorts of lower risk patients. The most common adverse events reported in clinical and observational studies are genital infections; however, the overall risk of these events appears to be low and easily managed. Similar safety profiles have been reported for elderly and younger patients. There is still some debate regarding the safety of canagliflozin in patients at high risk of fracture and amputation. Outstanding questions include specific patterns of cardiovascular protection according to baseline risk

    Immigration Enforcement and Fairness to Would-Be Immigrants

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    This chapter argues that governments have a duty to take reasonably effective and humane steps to minimize the occurrence of unauthorized migration and stay. While the effects of unauthorized migration on a country’s citizens and institutions have been vigorously debated, the literature has largely ignored duties of fairness to would-be immigrants. It is argued here that failing to take reasonable steps to prevent unauthorized migration and stay is deeply unfair to would-be immigrants who are not in a position to bypass visa regulations. Importantly, the argument here is orthogonal to the debate as to how much and what kinds of immigration ought to be allowed

    Use of antiretroviral drugs to prevent the transmission and acquisition of HIV

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    In 2016, London became the third city in the world to achieve the United Nations 90:90:90 HIV target (90% of people living with HIV diagnosed, 90% of those diagnosed are on treatment and 90% of those on treatment have an undetectable viral load) attaining 90:97:97 (88:96:97 for England as a whole) (Public Health England, 2017). New HIV diagnoses among gay, bisexual and other men who have sex with men have also fallen for the first time since the epidemic began 30 years ago (Public Health England, 2017). This remarkable progress is a result of a combination of interventions. This editorial outlines two of these which use antiretrovirals for the prevention of transmission and acquisition of HIV
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