Science Bulletin最新文献

Characterization of transport pathways and depositional changes in Mercury (Hg) and their connection to climatic and environmental changes on various time scales are crucial for better understanding the anthropogenic impacts on the global Hg cycle in the Anthropocene epoch. In this study, we examined Hg variations recorded in a stalagmite from central China, covering the period from 25.5 to 10.9 thousand years ago. Our data show a marked increase in Hg concentrations during the late Last Glacial Maximum, which coincided with the period of highest dust deposition on the Chinese Loess Plateau. Hg concentrations were lower during Heinrich events 1 and 2 and the Younger Dryas but higher during the Bølling-Allerød and the early Holocene. We suggest that regional dust load, which enhances atmospheric dry deposition of Hg, is the primary factor influencing Hg deposition in central China on glacial-interglacial timescales. On millennial-to-centennial timescales, climate also plays a significant role. Warmer and wetter conditions increase vegetation, litterfall, and soil/rock weathering, which in turn boost mineral dissolution and soil erosion in the vadose zone. These processes collectively result in higher Hg concentrations in the stalagmite.

Uranium pollution has become a serious threat to human health and environmental safety, making the detection of environmental uranium contamination of great importance. The sensitive and specific detection of uranyl ions, which are the dominant form of uranium in the environment, depends on the specific recognition of uranyl ions by chemical groups. In this study, a novel fluorescent sensor containing a highly specific uranyl ion recognition group is synthesized via the reaction of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and 1,1,2,2-tetra(4-carboxylphenyl)ethylene (TPE-(COOH)₄). Owing to the effects of aggregation-induced emission (AIE) and intramolecular charge transfer (ICT), the fluorescent sensor, named TPE-EDC, exhibits significant fluorescent properties in aqueous environments. The binding of uranyl ions by specific recognition groups in TPE-EDC leads to a decrease in the ICT effect, thus causing a significant reduction in the emission intensity of TPE-EDC. The attenuation of the fluorescence intensity of TPE-EDC shows an excellent linear relationship with an increase in uranyl ion concentration. TPE-EDC exhibits ultra-sensitive and ultra-selective detection ability for uranyl ions with an ultra-low detection limit of 69 pmol/L and an ultrashort response time of 30 s. These high detection performances render the fluorescent sensor TPE-EDC a promising candidate for early warning of uranium pollution.

Temperature affects both the thermodynamics of intermediate adsorption and the kinetics of elementary reactions. Despite its extensive study in thermocatalysis, temperature effect is typically overlooked in electrocatalysis. This study investigates how electrolyte temperature influences CO₂ electroreduction over Cu catalysts. Theoretical calculations reveal the significant impact of temperature on *CO and *H intermediate adsorption thermodynamics, water microenvironment at the electrode surface, and the electron density and covalent property of the C-O bond in the *CH-COH intermediate, crucial for the reaction pathways. The theoretical calculations are strongly verified by experimental results over different Cu catalysts. Faradaic efficiency (FE) toward multicarbon (C₂₊) products is favored at low temperatures. Cu nanorod electrode could achieve a [Formula: see text] value of 90.1 % with a current density of ∼400 mA cm^-2 at -3 °C. [Formula: see text] and [Formula: see text] show opposite trends with decreasing temperature. The [Formula: see text] ratio can decrease from 1.86 at 40 °C to 0.98 at -3 °C.

Lacustrine systems since the Mesozoic have sequestered large quantities of organic carbon, which may have important value for global climate cooling, but there is still a lack of geological evidence of this sequestration. Taking the Songliao Basin in China as a case study, we elucidate the important function of lacustrine basins as sinks of a large amount of organic carbon, particularly when the contemporaneous marine sediments were poor sinks of organic carbon. Volcanic activities and orbital forcing were likely key factors influencing the water transportation between the land and oceans, as well as the alternating burial of organic carbon in the oceans and land. Microorganisms related to methane metabolism may have been highly involved in the mineralization and sequestration of lacustrine organic carbon. This study provides new insights into the coupled carbon-water cycle between the land and oceans and the influence of this process on global climate evolution.

Extensive efforts have been put into reducing the heavy burden of esophageal squamous cell carcinoma (ESCC) in China. However, the joint impact of prevention and treatment on the long-term overall survival (OS) of ESCC patients remains largely unknown. We consecutively recruited 13,255 ESCC patients from two Chinese centers: the Northern center, located in a high-risk area with abundant screening programs; and the Southern center, situated in a non-high-risk area with improved clinical practices. Inter-center comparison, longitudinal intra-center comparison, and a simulation analysis were conducted to investigate the influence of tumor downstaging and high-quality clinical treatment on OS. During a follow-up period of 12.52 years, the Northern center exhibited higher median survival than the Southern center (6.22 vs. 3.15 years; HR_adjusted = 0.73, 95% CI: 0.69-0.77). Mediation analysis demonstrated that its OS advantage was largely (77.7%) attributed to earlier TNM stage (stage 0-II: 51.3% vs. 24.6%). In temporal analyses, patient survival in the Southern center gradually improved (median survival during 2015-2018 vs. 2009-2014: 3.58 vs. 2.93 years; HR_adjusted = 0.86, 95% CI: 0.79-0.94), coinciding with the progress of treatment-related indices (completeness of TNM staging in discharge diagnosis [from 53.7% to 99.6%], adoption of minimally invasive esophagectomy [from 0.0% to 51.1%] and right thoracic esophagectomy [from 12.4% to 86.4%], etc.). Simulation analysis further demonstrated that integrating both downstaging and high-quality treatment would lead to the best survival. Tumor downstaging and high-quality clinical treatment have a joint impact on ESCC patient survival. Establishing a comprehensive strategy that integrates cancer prevention with optimal clinical treatment is crucial for alleviating the ESCC burden.