Power Dependent Lineshape Corrections for Quantitative Spectroscopy

The Voigt profile - a convolution of a Gaussian and a Lorentzian - accurately describes the absorption lines of atomic and molecular gases at low probe powers. Fitting such to experimental spectra yields both the Lorentzian natural linewidth and the Gaussian Doppler broadening. However, as the probe power increases saturation effects introduce spurious power dependence into the fitted Doppler width. Using a simple atomic model, we calculate power-dependent corrections to the Voigt profile, which are parametrized by the Gaussian Doppler width, the Lorentzian natural linewidth, and the optical depth. We show numerically and experimentally that including the correction term substantially reduces the spurious power dependence in the fitted Gaussian width.Comment: 4 pages, 3 figure

Quantitative atomic spectroscopy for primary thermometry

Quantitative spectroscopy has been used to measure accurately the Doppler-broadening of atomic transitions in $^{85}$Rb vapor. By using a conventional platinum resistance thermometer and the Doppler thermometry technique, we were able to determine $k_B$ with a relative uncertainty of $4.1\times 10^{-4}$, and with a deviation of $2.7\times 10^{-4}$ from the expected value. Our experiment, using an effusive vapour, departs significantly from other Doppler-broadened thermometry (DBT) techniques, which rely on weakly absorbing molecules in a diffusive regime. In these circumstances, very different systematic effects such as magnetic sensitivity and optical pumping are dominant. Using the model developed recently by Stace and Luiten, we estimate the perturbation due to optical pumping of the measured $k_B$ value was less than $4\times 10^{-6}$. The effects of optical pumping on atomic and molecular DBT experiments is mapped over a wide range of beam size and saturation intensity, indicating possible avenues for improvement. We also compare the line-broadening mechanisms, windows of operation and detection limits of some recent DBT experiments

Synthesis, structure and dioxygen reactivity of a bis(µ-iodo)dicopper(I) complex supported by the [N-(3,5-di-tert-butyl-2-hydroxybenzyl)-N,N-di-(2-pyridylmethyl)]amine ligand

The air-sensitive bis(µ-iodo)dicopper(I) complex 1 supported by [N-(3,5-di-tert-butyl-2-hydroxybenzyl)-N,N-di-(2-pyridylmethyl)]amine (L) has been prepared by treating copper(I) iodide with L in anhydrous THF. Compound 1 crystallizes as a dimer in space group C2/c. Each copper(I) center has distorted tetrahedral N2I2 coordination geometry with Cu–N(pyridyl) distances 2.061(3) and 2.063(3) Å, Cu–I distances 2.6162(5) and 2.7817(5) and a CuCu distance of 2.9086(8) Å. Complex 1 is rapidly oxidized by dioxygen in CH2Cl2 with a 1 : 1 stoichiometry giving the bis(µ-iodo)peroxodicopper(II) complex [Cu(L)(µ-I)]2O2 (2). The reaction of 1 with dioxygen has been characterized by UV-vis, mass spectrometry, EPR and Cu K-edge X-ray absorption spectroscopy at low temperature (193 K) and above. The mass spectrometry and low temperature EPR measurements suggested an equilibrium between the bis(µ-iodo)peroxodicopper(II) complex 2 and its dimer, namely, the tetranuclear (peroxodicopper(II))2 complex [Cu(L)(µ-I)]4O4 (2). Complex 2 undergoes an effective oxo-transfer reaction converting PPh3 into OPPh3 under anaerobic conditions. At sufficiently high concentration of PPh3, the oxygen atom transfer from 2 to PPh3 was followed by the formation of [Cu(PPh3)3I]. The dioxygen reactivity of 1 was compared with that known for other halo(amine)copper(I) dimers

Between-occupation differences in work-related COVID-19 mitigation strategies over time: Analysis of the Virus Watch Cohort in England and Wales

OBJECTIVES: COVID-19 mitigations have had a profound impact on workplaces, however, multisectoral comparisons of how work-related mitigations were applied are limited. This study aimed to investigate (i) occupational differences in the usage of key work-related mitigations over time and (ii) workers' perceptions of these mitigations. METHODS: Employed/self-employed Virus Watch study participants (N=6279) responded to a mitigation-related online survey covering the periods of December 2020-February 2022. Logistic regression was used to investigate occupation- and time-related differences in the usage of work-related mitigation methods. Participants' perceptions of mitigation methods were investigated descriptively using proportions. RESULTS: Usage of work-related mitigation methods differed between occupations and over time, likely reflecting variation in job roles, workplace environments, legislation and guidance. Healthcare workers had the highest predicted probabilities for several mitigations, including reporting frequent hand hygiene [predicted probability across all survey periods 0.61 (95% CI 0.56-0.66)] and always wearing face coverings [predicted probability range 0.71 (95% CI 0.66-0.75) - 0.80 (95% CI 0.76-0.84) across survey periods]. There were significant cross-occupational trends towards reduced mitigations during periods of less stringent national restrictions. The majority of participants across occupations (55-88%) agreed that most mitigations were reasonable and worthwhile even after the relaxation of national restrictions; agreement was lower for physical distancing (39-44%). CONCLUSIONS: While usage of work-related mitigations appeared to vary alongside stringency of national restrictions, agreement that most mitigations were reasonable and worthwhile remained substantial. Further investigation into the factors underlying between-occupational differences could assist pandemic planning and prevention of workplace COVID-19 transmission

Absolute absorption line-shape measurements at the shot-noise limit

Here, we report a measurement scheme for determining an absorption profile with an accuracy imposed solely by photon shot noise. We demonstrate the power of this technique by measuring the absorption of cesium vapor with an uncertainty at the 2-ppm level. This extremely high signal-to-noise ratio allows us to directly observe the homogeneous line-shape component of the spectral profile, even in the presence of Doppler broadening, by measuring the spectral profile at a frequency detuning more than 200 natural linewidths from the line center. We then use this tool to discover an optically induced broadening process that is quite distinct from the well-known power broadening phenomenon

Cost-effectiveness analysis of sacubitril/valsartan vs enalapril in patients with heart failure and reduced ejection fraction

Importance  The angiotensin receptor neprilysin inhibitor sacubitril/valsartan was associated with a reduction in cardiovascular mortality, all-cause mortality, and hospitalizations compared with enalapril. Sacubitril/valsartan has been approved for use in heart failure (HF) with reduced ejection fraction in the United States and cost has been suggested as 1 factor that will influence the use of this agent. Objective  To estimate the cost-effectiveness of sacubitril/valsartan vs enalapril in the United States. Design, Setting, and Participants  Data from US adults (mean [SD] age, 63.8 [11.5] years) with HF with reduced ejection fraction and characteristics similar to those in the PARADIGM-HF trial were used as inputs for a 2-state Markov model simulated HF. Risks of all-cause mortality and hospitalization from HF or other reasons were estimated with a 30-year time horizon. Quality of life was based on trial EQ-5D scores. Hospital costs combined Medicare and private insurance reimbursement rates; medication costs included the wholesale acquisition cost for sacubitril/valsartan and enalapril. A discount rate of 3% was used. Sensitivity analyses were performed on key inputs including: hospital costs, mortality benefit, hazard ratio for hospitalization reduction, drug costs, and quality-of-life estimates. Main Outcomes and Measures  Hospitalizations, quality-adjusted life-years (QALYs), costs, and incremental costs per QALY gained. Results  The 2-state Markov model of US adult patients (mean age, 63.8 years) calculated that there would be 220 fewer hospital admissions per 1000 patients with HF treated with sacubitril/valsartan vs enalapril over 30 years. The incremental costs and QALYs gained with sacubitril/valsartan treatment were estimated at $35 512 and 0.78, respectively, compared with enalapril, equating to an incremental cost-effectiveness ratio (ICER) of$45 017 per QALY for the base-case. Sensitivity analyses demonstrated ICERs ranging from $35 357 to$75 301 per QALY. Conclusions and Relevance  For eligible patients with HF with reduced ejection fraction, the Markov model calculated that sacubitril/valsartan would increase life expectancy at an ICER consistent with other high-value accepted cardiovascular interventions. Sensitivity analyses demonstrated sacubitril/valsartan would remain cost-effective vs enalapril

Associations of apolipoprotein E exon 4 and lipoprotein lipase S447X polymorphisms with acute ischemic stroke and myocardial infarction

Background: Because apolipoprotein E (apoE) and lipopoprotein lipase (LPL) polymorphisms interact with each other and with other factors to affect lipid metabolism, we sought to determine their separate and combined effects in association with ischemic vascular disease. Methods: We performed a case-control study of 816 subjects: 246 acute ischemic stroke patients, 234 acute myocardial infarction patients, and 336 controls. APOE exon 4 and LPL S447X genotypes were determined. Results: APOE ε2 and ε4 homozygotes were increased in stroke (4.5% vs. 1.0%, p = 0.008), while in myocardial infarction the ε4 allele was increased (12.6% vs. 9.5%, p = 0.006) but ε2 was decreased (3.7% vs. 12.1%, p = 0.000006). For subjects with either APOE ε2 or ε4 alleles, LPL X alleles were increased in vascular disease (OR = 2.2, p = 0.01). LPL X alleles displayed opposite tendencies toward association with disease when subjects were divided by sex, smoking, or APOE genotype. Meta-analysis and regression analysis of previous studies supported the sex and smoking dichotomies. Conclusion: This is the first report of an association of vascular disease with an interaction of APOE exon 4 and LPL S447X genotypes. Therefore, APOE genotypes and LPL S447X interactions with apoE, sex, and smoking may affect the risk of myocardial infarction and ischemic stroke. © 2006 by Walter de Gruyter.published_or_final_versio

The changing contributory role to infections of work, public transport, shopping, hospitality and leisure activities throughout the SARS-CoV-2 pandemic in England and Wales

Background: Understanding how non-household activities contributed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections under different levels of national health restrictions is vital. // Methods: Among adult Virus Watch participants in England and Wales, we used multivariable logistic regressions and adjusted-weighted population attributable fractions (aPAF) assessing the contribution of work, public transport, shopping, and hospitality and leisure activities to infections. // Results: Under restrictions, among 17,256 participants (502 infections), work [adjusted odds ratio (aOR) 2.01 (1.65–2.44), (aPAF) 30% (22–38%)] and transport [(aOR 1.15 (0.94–1.40), aPAF 5% (-3–12%)], were risk factors for SARS-CoV-2 but shopping, hospitality and leisure were not. Following the lifting of restrictions, among 11,413 participants (493 infections), work [(aOR 1.35 (1.11–1.64), aPAF 17% (6–26%)] and transport [(aOR 1.27 (1.04–1.57), aPAF 12% (2–22%)] contributed most, with indoor hospitality [(aOR 1.21 (0.98–1.48), aPAF 7% (-1–15%)] and leisure [(aOR 1.24 (1.02–1.51), aPAF 10% (1–18%)] increasing. During the Omicron variant, with individuals more socially engaged, among 11,964 participants (2335 infections), work [(aOR 1.28 (1.16–1.41), aPAF (11% (7–15%)] and transport [(aOR 1.16 (1.04–1.28), aPAF 6% (2–9%)] remained important but indoor hospitality [(aOR 1.43 (1.26–1.62), aPAF 20% (13–26%)] and leisure [(aOR 1.35 (1.22–1.48), aPAF 10% (7–14%)] dominated. // Conclusions: Work and public transport were important to transmissions throughout the pandemic with hospitality and leisure’s contribution increasing as restrictions were lifted, highlighting the importance of restricting leisure and hospitality alongside advising working from home, when facing a highly infectious and virulent respiratory infection

Symptom profiles of community cases infected by influenza, RSV, rhinovirus, seasonal coronavirus, and SARS-CoV-2 variants of concern

Respiratory viruses that were suppressed through previous lockdowns during the COVID-19 pandemic have recently started to co-circulate with SARS-CoV-2. Understanding the clinical characteristics and symptomatology of different respiratory viral infections can help address the challenges related to the identification of cases and the understanding of SARS-CoV-2 variants' evolutionary patterns. Flu Watch (2006-2011) and Virus Watch (2020-2022) are household community cohort studies monitoring the epidemiology of influenza, respiratory syncytial virus, rhinovirus, seasonal coronavirus, and SARS-CoV-2, in England and Wales. This study describes and compares the proportion of symptoms reported during illnesses infected by common respiratory viruses. The SARS-CoV-2 symptom profile increasingly resembles that of other respiratory viruses as new strains emerge. Increased cough, sore throat, runny nose, and sneezing are associated with the emergence of the Omicron strains. As SARS-CoV-2 becomes endemic, monitoring the evolution of its symptomatology associated with new variants will be critical for clinical surveillance