124 research outputs found

    Feasibility of UV lasing without inversion in mercury vapor

    Full text link
    We investigate the feasibility of UV lasing without inversion at a wavelength of 253.7253.7 nm utilizing interacting dark resonances in mercury vapor. Our theoretical analysis starts with radiation damped optical Bloch equations for all relevant 13 atomic levels. These master equations are generalized by considering technical phase noise of the driving lasers. From the Doppler broadened complex susceptibility we obtain the stationary output power from semiclassical laser theory. The finite overlap of the driving Gaussian laser beams defines an ellipsoidal inhomogeneous gain distribution. Therefore, we evaluate the intra-cavity field inside a ring laser self-consistently with Fourier optics. This analysis confirms the feasibility of UV lasing and reveals its dependence on experimental parameters.Comment: changes were made according to reviewer comments (accepted for publication in JOSA B

    Data Segmentation in Electronic Health Information Exchange: Policy Considerations and Analysis

    Get PDF
    The issue of whether and, if so, to what extent patients should have control over the sharing or withholding of their health information represents one of the foremost policy challenges related to electronic health information exchange. It is widely acknowledged that patients\u27 health information should flow where and when it is needed to support the provision of appropriate and high-quality care. Equally significant, however, is the notion that patients want their needs and preferences to be considered in the determination of what information is shared with other parties, for what purposes, and under what conditions. Some patients may prefer to withhold or sequester certain elements of health information, often when it is deemed by them (or on their behalf) to be sensitive, whereas others may feel strongly that all of their health information should be shared under any circumstance. This discussion raises the issue of data segmentation, which we define for the purposes of this paper as the process of sequestering from capture, access or view certain data elements that are perceived by a legal entity, institution, organization, or individual as being undesirable to share. This whitepaper explores key components of data segmentation, circumstances for its use, associated benefits and challenges, various applied approaches, and the current legal environment shaping these endeavors

    Identifying mixed Mycobacterium tuberculosis infections from whole genome sequence data.

    Get PDF
    BACKGROUND: Mixed, polyclonal Mycobacterium tuberculosis infection occurs in natural populations. Developing an effective method for detecting such cases is important in measuring the success of treatment and reconstruction of transmission between patients. Using whole genome sequence (WGS) data, we assess two methods for detecting mixed infection: (i) a combination of the number of heterozygous sites and the proportion of heterozygous sites to total SNPs, and (ii) Bayesian model-based clustering of allele frequencies from sequencing reads at heterozygous sites. RESULTS: In silico and in vitro artificially mixed and known pure M. tuberculosis samples were analysed to determine the specificity and sensitivity of each method. We found that both approaches were effective in distinguishing between pure strains and mixed infection where there was relatively high (> 10%) proportion of a minor strain in the mixture. A large dataset of clinical isolates (n = 1963) from the Karonga Prevention Study in Northern Malawi was tested to examine correlations with patient characteristics and outcomes with mixed infection. The frequency of mixed infection in the population was found to be around 10%, with an association with year of diagnosis, but no association with age, sex, HIV status or previous tuberculosis. CONCLUSIONS: Mixed Mycobacterium tuberculosis infection was identified in silico using whole genome sequence data. The methods presented here can be applied to population-wide analyses of tuberculosis to estimate the frequency of mixed infection, and to identify individual cases of mixed infections. These cases are important when considering the evolution and transmission of the disease, and in patient treatment

    Formation of Super-Earths

    Full text link
    Super-Earths are the most abundant planets known to date and are characterized by having sizes between that of Earth and Neptune, typical orbital periods of less than 100 days and gaseous envelopes that are often massive enough to significantly contribute to the planet's overall radius. Furthermore, super-Earths regularly appear in tightly-packed multiple-planet systems, but resonant configurations in such systems are rare. This chapters summarizes current super-Earth formation theories. It starts from the formation of rocky cores and subsequent accretion of gaseous envelopes. We follow the thermal evolution of newly formed super-Earths and discuss their atmospheric mass loss due to disk dispersal, photoevaporation, core-cooling and collisions. We conclude with a comparison of observations and theoretical predictions, highlighting that even super-Earths that appear as barren rocky cores today likely formed with primordial hydrogen and helium envelopes and discuss some paths forward for the future.Comment: Invited review accepted for publication in the 'Handbook of Exoplanets,' Planet Formation section, Springer Reference Works, Juan Antonio Belmonte and Hans Deeg, Ed

    Planet Populations as a Function of Stellar Properties

    Full text link
    Exoplanets around different types of stars provide a window into the diverse environments in which planets form. This chapter describes the observed relations between exoplanet populations and stellar properties and how they connect to planet formation in protoplanetary disks. Giant planets occur more frequently around more metal-rich and more massive stars. These findings support the core accretion theory of planet formation, in which the cores of giant planets form more rapidly in more metal-rich and more massive protoplanetary disks. Smaller planets, those with sizes roughly between Earth and Neptune, exhibit different scaling relations with stellar properties. These planets are found around stars with a wide range of metallicities and occur more frequently around lower mass stars. This indicates that planet formation takes place in a wide range of environments, yet it is not clear why planets form more efficiently around low mass stars. Going forward, exoplanet surveys targeting M dwarfs will characterize the exoplanet population around the lowest mass stars. In combination with ongoing stellar characterization, this will help us understand the formation of planets in a large range of environments.Comment: Accepted for Publication in the Handbook of Exoplanet

    Design, Formulation, and Evaluation of Novel Dissolving Microarray Patches Containing Rilpivirine for Intravaginal Delivery

    Get PDF
    Antiretroviral (ARV) drugs have, for many years, been studied and administered in the prevention and treatment of human immunodeficiency virus (HIV). Intramuscular (IM) injection of long acting (LA) ARVs are in clinical development, but injectable formulations require regular access to healthcare facilities and disposal facilities for sharps. The development of a discrete, self‐administered, and self‐disabling vehicle to deliver ARVs could obviate these issues. This study describes the formulation, mechanical characterization, and in vivo evaluation of dissolving microarray patches (MAPs) containing a LA nanosuspension of the ARV, rilpivirine (RPV, RPV LA), for vaginal delivery. This is the first study to apply MAPs into vaginal tissue. The RPV LA MAPs penetrate ex vivo skin and a synthetic vaginal skin model and withstand the effects of potential dragging motion across synthetic vaginal epithelium. In in vivo studies, the mean plasma concentration of RPV in rats at the 56 day endpoint (116.5 ng mL−1) is comparable to that achieved in the IM control cohort (118.9 ng mL−1). RPV is detected systemically, in lymph and vaginal tissue, indicating the potential to deliver RPV LA to primary sites of viral challenge and replication. This innovative research has future potential for patients and healthcare workers, particularly in low‐resource settings

    Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

    Get PDF
    Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049
    • 

    corecore