Radiocarbon (14C) measurements play important roles in dating and tracing applications where the isotopic concentration can differ from 0.1 to 106 pMC (percent modern carbon). A liquid scintillation counter cannot provide enough sensitivity when dealing with low-concentration samples of limited amounts over a reasonable time period. Accelerator mass spectroscopy (AMS) measures low-concentrations well but must first do dilution for high-concentration samples, and suffers from high instrument and maintenance costs. Saturated absorption CAvity Ring-down spectroscopy (SCAR) has now been developed into a practical technique with performances close to AMS but at much lower costs. The dynamic range covers 1–105 pMC, and the measurement uncertainties in the range of 0.4–1 pMC can be achieved within 0.5–2.5 hr of operation time. SCAR measures CO2 gases directly without graphitization in sample preparation. The typical sample consumption is ∼1 mg of carbon mass and the time for sample preparation can be as short as 15 min. Applications of SCAR to Suess-effect evaluation, biogenic-component analysis, ancient- and modern-sample dating, food-fraud detection and medicine-metabolism study have all been demonstrated by employing a close-to-automatic sample preparation system.

Predicting epidemic trends of coronavirus disease 2019 (COVID-19) remains a key public health concern globally today. However, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection rate in previous studies of the transmission dynamics model was mostly a fixed value. Therefore, we proposed a meta-Susceptible-Exposed-Infectious-Recovered-Susceptible (SEIRS) model by adding a time-varying SARS-CoV-2 reinfection rate to the transmission dynamics model to more accurately characterize the changes in the number of infected persons. The time-varying reinfection rate was estimated using random-effect multivariate meta-regression based on published literature reports of SARS-CoV-2 reinfection rates. The meta-SEIRS model was constructed to predict the epidemic trend of COVID-19 from February to December 2023 in Sichuan province. Finally, according to the online questionnaire survey, the SARS-CoV-2 infection rate at the end of December 2022 in Sichuan province was 82.45%. The time-varying effective reproduction number in Sichuan province had two peaks from July to December 2022, with a maximum peak value of about 15. The prediction results based on the meta-SEIRS model showed that the highest peak of the second wave of COVID-19 in Sichuan province would be in late May 2023. The number of new infections per day at the peak would be up to 2.6 million. We constructed a meta-SEIRS model to predict the epidemic trend of COVID-19 in Sichuan province, which was consistent with the trend of SARS-CoV-2 positivity in China. Therefore, a meta-SEIRS model parameterized based on evidence-based data can be more relevant to the actual situation and thus more accurately predict future trends in the number of infections.

Tea is one of the most widely consumed beverages in the world. However, the association between tea and risk of pancreatic adenocarcinoma remains controversial. This study aimed to investigate the causal relationship between tea consumption and risk of pancreatic adenocarcinoma and to explore their mediating effects. The two-sample Mendelian randomisation (MR) analysis showed an inverse causal relationship between tea intake and pancreatic adenocarcinoma (OR: 0·111 (0·02, 0·85), P < 0·04). To examine the mediating effects, we explored the potential mechanisms by which tea intake reduces the risk of pancreatic adenocarcinoma. Based on the oral bioavailability and drug-like properties in Traditional Chinese Medicine Systems Pharmacology database, we selected the main active ingredients of tea. We screened out the fifteen representative targeted genes by Pharmmapper database, and the gene ontology enrichment analysis showed that these targeted genes were related to vascular endothelial growth factor (VEGF) pathway. The two-step MR analysis of results showed that only VEGF-D played a mediating role, with a mediation ratio of 0·230 (0·066, 0·394). In conclusion, the findings suggest that VEGF-D mediates the effect of tea intake on the risk of pancreatic adenocarcinoma.

Fast neutron absorption spectroscopy is widely used in the study of nuclear structure and element analysis. However, due to the traditional neutron source pulse duration being of the order of nanoseconds, it is difficult to obtain a high-resolution absorption spectrum. Thus, we present a method of ultrahigh energy-resolution absorption spectroscopy via a high repetition rate, picosecond duration pulsed neutron source driven by a terawatt laser. The technology of single neutron count is used, which results in easily distinguishing the width of approximately 20 keV at 2 MeV and an asymmetric shape of the neutron absorption peak. The absorption spectroscopy based on a laser neutron source has one order of magnitude higher energy-resolution power than the state-of-the-art traditional neutron sources, which could be of benefit for precisely measuring nuclear structure data.