<i>C</i>_m‑History Method, a Novel Approach to Simultaneously Measure Source and Sink Parameters Important for Estimating Indoor Exposures to Phthalates

The concentration of a gas-phase semivolatile organic compound (SVOC) in equilibrium with its mass-fraction in the source material, <i>y</i>₀, and the coefficient for partitioning of an SVOC between clothing and air, <i>K</i>, are key parameters for estimating emission and subsequent dermal exposure to SVOCs. Most of the available methods for their determination depend on achieving steady-state in ventilated chambers. This can be time-consuming and of variable accuracy. Additionally, no existing method simultaneously determines <i>y</i>₀ and <i>K</i> in a single experiment. In this paper, we present a sealed-chamber method, using early-stage concentration measurements, to simultaneously determine <i>y</i>₀ and <i>K</i>. The measurement error for the method is analyzed, and the optimization of experimental parameters is explored. Using this method, <i>y</i>₀ for phthalates (DiBP, DnBP, and DEHP) emitted by two types of PVC flooring, coupled with <i>K</i> values for these phthalates partitioning between a cotton T-shirt and air, were measured at 25 and 32 °C (room and skin temperatures, respectively). The measured <i>y</i>₀ values agree well with results obtained by alternate methods. The changes of <i>y</i>₀ and <i>K</i> with temperature were used to approximate the changes in enthalpy, Δ<i><i>H</i></i>, associated with the relevant phase changes. We conclude with suggestions for further related research

Datasheet1_Evaluating the impact of sickle cell disease on COVID-19 susceptibility and severity: a retrospective cohort study based on electronic health record.docx

BackgroundSickle cell trait/disease (SCT/SCD) are enriched among Black people and associated with various comorbidities. The overrepresentation of these characteristics prevents traditional regression approach obtaining convincing evidence for the independent effect of SCT/SCD on other health outcomes. This study aims to investigate the association between SCT/SCD and COVID-19-related outcomes using causal inference approaches that balance the covariate.MethodsWe leveraged electronic health record (EHR) data from the University of Chicago Medicine between March 2020 and December 2021. Demographic characteristics were retrieved. Medical conditions were identified using ICD-10 codes. Five approaches, including two traditional regression approaches (unadjusted and adjusted) and three causal inference approaches [covariate balancing propensity score (CBPS) matching, CBPS weighting, and CBPS adjustment], were employed.ResultsA total of 112,334 patients were included in the study, among which 504 had SCT and 388 SCD. Patients with SCT/SCD were more likely to be non-Hispanic Black people, younger, female, non-smokers, and had a diagnosis of diabetes, heart failure, asthma, and cerebral infarction. Causal inference approaches achieved a balanced distribution of these covariates while traditional approaches failed. Across these approaches, SCD was consistently associated with COVID-19-related pneumonia (odds ratios (OR) estimates, 3.23 (95% CI: 2.13–4.89) to 2.57 (95% CI: 1.10–6.00)) and pain (OR estimates, 6.51 (95% CI: 4.68–9.06) to 2.47 (95% CI: 1.35–4.49)). While CBPS matching suggested an association between SCD and COVID-19-related acute respiratory distress syndrome (OR = 2.01, 95% CI: 0.97–4.17), this association was significant in other approaches (OR estimates, 2.96 (95% CI: 1.69–5.18) to 2.50 (95% CI: 1.43–4.37)). No association was observed between SCT and COVID-19-related outcomes in causal inference approaches.ConclusionUsing causal inference approaches, we provide comprehensive evidence for the link between SCT/SCD and COVID-19-related outcomes.</p

Cs₂AgInCl₆ Double Perovskite Single Crystals: Parity Forbidden Transitions and Their Application For Sensitive and Fast UV Photodetectors

Double perovskite Cs₂AgInCl₆ is newly reported as a stable and environmentally friendly alternative to lead halide perovskites. However, the fundamental properties of this material remain unexplored. Here, we first produced high-quality Cs₂AgInCl₆ single crystals (SCs) with a low trap density of 8.6 × 10⁸ cm^–3, even lower than the value reported in the best lead halide perovskite SCs. Through systematical optical and electronic characterization, we experimentally verified the existence of the proposed parity-forbidden transition in Cs₂AgInCl₆ and identified the role of oxygen in controlling its optical properties. Furthermore, sensitive (dectivity of ∼10¹² Jones), fast (3 dB bandwidth of 1035 Hz), and stable UV photodetectors were fabricated based on our Cs₂AgInCl₆ SCs, showcasing their advantages for optoelectronic applications

Sensing Behavior of Atomically Thin-Layered MoS₂ Transistors

Most of recent research on layered chalcogenides is understandably focused on single atomic layers. However, it is unclear if single-layer units are the most ideal structures for enhanced gas–solid interactions. To probe this issue further, we have prepared large-area MoS₂ sheets ranging from single to multiple layers on 300 nm SiO₂/Si substrates using the micromechanical exfoliation method. The thickness and layering of the sheets were identified by optical microscope, invoking recently reported specific optical color contrast, and further confirmed by AFM and Raman spectroscopy. The MoS₂ transistors with different thicknesses were assessed for gas-sensing performances with exposure to NO₂, NH₃, and humidity in different conditions such as gate bias and light irradiation. The results show that, compared to the single-layer counterpart, transistors of few MoS₂ layers exhibit excellent sensitivity, recovery, and ability to be manipulated by gate bias and green light. Further, our <i>ab initio</i> DFT calculations on single-layer and bilayer MoS₂ show that the charge transfer is the reason for the decrease in resistance in the presence of applied field