Application of the non-adiabatic molecular dynamics (NAMD) approach is limited to studying carrier dynamics in the momentum space, as a supercell is required to sample the phonon excitation and ...electron-phonon (e-ph) interaction at different momenta in a molecular dynamics simulation. Here we develop an ab initio approach for the real-time charge carrier quantum dynamics in the momentum space (NAMD_k) by directly introducing e-ph coupling into the Hamiltonian based on the harmonic approximation. The NAMD_k approach maintains the zero-point energy and includes memory effects of carrier dynamics. The application of NAMD_k to the hot carrier dynamics in graphene reveals the phonon-specific relaxation mechanism. An energy threshold of 0.2 eV-defined by two optical phonon modes-separates the hot electron relaxation into fast and slow regions with lifetimes of pico- and nanoseconds, respectively. The NAMD_k approach provides an effective tool to understand real-time carrier dynamics in the momentum space for different materials.
Discriminating the significant human-induced vegetation changes over the past 15 years could help local governments review the effects of eco-programs and develop sustainable land use policies in ...arid/semi-arid ecosystems. We used the residual trends method (RESTREND) to estimate the human-induced and climate-induced vegetation changes. Two typical regions in the Horqin Sandy Land of China were selected as study areas. We first detected vegetation dynamics between 2000–2014 using Sen’s slope estimation and the Mann–Kendall test detection method (SMK) based on the Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) time series, then used RESTREND to profile human modifications in areas of significant vegetation change. RESTREND was optimized using statistical and trajectory analysis to automatically identify flexible spatially homogeneous neighborhoods, which were essential for determining the reference areas. The results indicated the following. (1) Obvious vegetation increases happened in both regions, but Naiman (64.1%) increased more than Ar Horqin (16.8%). (2) Climate and human drivers both contributed to significant changes. The two factors contributed equally to vegetation change in Ar Horqin, while human drivers contributed more in Naiman. (3) Human factors had a stronger influence on ecosystems, and were more responsible for vegetation decreases in both regions. Further evidences showed that the primary human drivers varied in regions. Grassland eco-management was the key driver in Ar Horqin, while farming was the key factor for vegetation change in Naiman.
Nowadays, trace CH4 emitted from vehicle exhausts severely threaten the balance of the ecology system of our earth. Thereby, the development of active and stable catalysts capable of methane ...conversion under mild conditions is critical. Here, we present a convenient method to redisperse catalytically inert PdO nanoparticles (NPs) (>10 nm) into reactive PdO x nanoclusters (∼2 nm) anchored on a Ce-doped LaFeO3 parent. Isothermally activated in an N2 flow, the redispersed catalyst achieved a CH4 conversion of 90% at 400 °C, which is significantly higher than the fresh and H2- and O2-treated counterparts (625, 616, and 641 °C, respectively), indicating the importance of the gas atmosphere in the redispersion of PdO NPs. In addition, the comprehensive catalyst characterizations demonstrated that the isolated Ce ions in the perovskite lattice play an irreplaceable role in the redispersion of reactive sites and the reduction of the energy barrier for C–H scission. More importantly, the Ce additive helps to stabilize the PdO x species by reducing overoxidation, resulting in significant lifetime extension. Through a thorough understanding of structural manipulation, this study sheds light on the design of highly performing supported catalysts for methane oxidation.
Per- and polyfluoroalkyl substances (PFASs), with their water- and heat-resistant properties, have been widely used in industrial and consumer products, including floor waxes. Adverse health effects ...are associated with PFAS exposures (e.g., increased risk of cancer and immunotoxicity); however, exposures resulting from the use of PFAS-containing products are poorly understood. This study examines PFAS emissions during professional floor stripping/waxing and their potential for occupational exposures. We measured PFASs in dust and airborne particulate matter (PM2.0, aerodynamic diameter ≤2.0 μm) before, during, and after floor stripping/waxing activities in three rooms in a university building. PM2.0 samples were analyzed for 34 targeted PFASs by ultra-high performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometer (UHPLC/ESI-MS/MS). In total, ten PFASs were detected in PM2.0 collected during floor stripping/waxing. Five were consistently higher during floor stripping/waxing compared to before (two with 95% confidence interval): perfluoro-2-methoxyacetic acid, perfluorobutanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, and perfluorooctane sulfonic acid. For these five, estimated exposures during floor stripping were 80.6, 320.5, 83.8, 29.6, and 157.7 pg m−3 per hour of floor stripping, respectively, one order of magnitude greater than typical residential indoor and two orders of magnitude greater than ambient outdoor concentrations. Estimated emission rates were 3.0, 9.6, 3.4, 1.5, and 6.5 ng h−1m−2, respectively (34.6% uncertainty). Inhalation occupational exposures were in the range of 9.42–23.2 pg per kg body weight per hour of floor stripping across the five PFASs.
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•PFASs in dust and airborne particulate matter (PM2.0) during professional floor stripping/waxing were measured.•PFASs emission rates from floor stripping/waxing were estimated.•Significantly higher levels of PFASs were measured during floor waxing.•Floor waxing could be an important source of PFAS contamination.•Floor waxing workers could have increased occupational health risks due to PFAS exposures.
We conducted a proof-of-concept, phase 2 trial to assess neoadjuvant SHR-1701 with or without chemotherapy, followed by surgery or radiotherapy, and then consolidation SHR-1701 in unresectable stage ...III non-small-cell lung cancer (NSCLC). In the primary cohort of patients receiving neoadjuvant combination therapy (n = 97), both primary endpoints were met, with a post-induction objective response rate of 58% (95% confidence interval CI 47-68) and an 18-month event-free survival (EFS) rate of 56.6% (95% CI 45.2-66.5). Overall, 27 (25%) patients underwent surgery; all achieved R0 resection. Among them, 12 (44%) major pathological responses and seven (26%) pathological complete responses were recorded. The 18-month EFS rate was 74.1% (95% CI 53.2-86.7) in surgical patients and 57.3% (43.0-69.3) in radiotherapy-treated patients. Neoadjuvant SHR-1701 with chemotherapy, followed by surgery or radiotherapy, showed promising efficacy with a tolerable safety profile in unresectable stage III NSCLC. Surgical conversion was feasible in a notable proportion of patients and associated with better survival outcomes.We conducted a proof-of-concept, phase 2 trial to assess neoadjuvant SHR-1701 with or without chemotherapy, followed by surgery or radiotherapy, and then consolidation SHR-1701 in unresectable stage III non-small-cell lung cancer (NSCLC). In the primary cohort of patients receiving neoadjuvant combination therapy (n = 97), both primary endpoints were met, with a post-induction objective response rate of 58% (95% confidence interval CI 47-68) and an 18-month event-free survival (EFS) rate of 56.6% (95% CI 45.2-66.5). Overall, 27 (25%) patients underwent surgery; all achieved R0 resection. Among them, 12 (44%) major pathological responses and seven (26%) pathological complete responses were recorded. The 18-month EFS rate was 74.1% (95% CI 53.2-86.7) in surgical patients and 57.3% (43.0-69.3) in radiotherapy-treated patients. Neoadjuvant SHR-1701 with chemotherapy, followed by surgery or radiotherapy, showed promising efficacy with a tolerable safety profile in unresectable stage III NSCLC. Surgical conversion was feasible in a notable proportion of patients and associated with better survival outcomes.
Water resources are one of the important factors that influence regional crop production and the food security of humans. Most traditional models of crop water demand analysis are built on the basis ...of a certain crop or macroscopic analysis, which neglect regional crop allocation and the difference of water demand in different crop growing periods. In this paper, a new assessing model, the satisfied degree of crop water requirement, is developed to assess the impacts of water resources on production of six main food crops in China. The six main food crops are spring wheat, winter wheat, corn, early season rice, middle-season rice and late rice. The results show that: (1) there are serious risks of water shortage in China, even in south China with its abundant precipitation; (2) the satisfied degree of crop water demand represents great temporal–spatial changes. On spatial distribution the risks are high in major bases of food production due to influences of cropping system and crop-combinations. Northwest China is a special interesting case. In seasonal fluctuation water shortage is severe in March and September. These risks seriously restrict food production in China. The results also show that the strategic measures of water resources management must be chosen carefully to deal with food security and regional sustainable development in China.
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•We develop a new SDCWR model to assess the satisfying degree of crop water requirement.•CWR for different crop types and growing seasons are assembled in the SDCWR model.•The SDCWR of the main food crops in China is analyzed.•Serious risk of the crop water demand exists in the food production in China.•The strategic measures of water resource management must be carefully chosen in China.
Glutathione-S-transferases mu 2 (GSTM2), a kind of important Phase II antioxidant enzyme of eukaryotes, is degraded by nonsense mediated mRNA decay due to a C27T substitution in the fifth exon of ...pigs. As a reproductive performance-related gene, GSTM2 is involved in embryo implantation, whereas, functional deficiency of GSTM2 induces pre- or post-natal death in piglets potentially. To have some insight into the role of GSTM2 in embryo development, high throughput RNA sequencing is performed using the swine testis cells (ST) with the deletion of GSTM2. Some embryo development-related genes are observed from a total of 242 differentially expressed genes, including STAT1, SRC, IL-8, DUSP family, CCL family and integrin family. GSTM2 affects expression of SRC, OPN, and SLCs. GSTM2 suppresses phosphorylation of STAT1 by binding to STAT1. In addition, as an important transcription factor, STAT1 regulates expression of uterus receptive-related genes including CCLs, IRF9, IFITs, MXs, and OAS. The present study provides evidence to molecular mechanism of GSTM2 modulating embryo development.
•The Mg0.05Zn0.95O film annealed at 600°C exhibits the highest photocatalytic activity.•Photocatalytic activity of the films are related to annealing temperature and Mg doping.•The peak at about ...420cm−1 is assigned to ZnO stretching vibration.
Magnesium doped zinc oxide (MgxZn1−xO) thin films were synthesized on silicon substrate through sol–gel process. Mg0.15Zn0.85O thin films were annealed at 500–800°C and ZnO, Mg0.1Zn0.9O, Mg0.05Zn0.95O thin films were annealed at 600°C for 60min, respectively. The results show that all the samples are of a hexagonal wurtzite structure of ZnO. The surface morphology is strongly dependent on mean grain size and surface fluctuation. Fourier transform infrared spectra reveal that the vibration peak at 420cm−1 is of the intrinsic lattice absorption of ZnO. The peak at 1083cm−1 belongs to SiOSi asymmetric stretching vibration. Photoluminescence spectra show that the ultraviolet emission (365–400nm) and the broad visible emission (469–569nm) are observed. In particular, Mg0.05Zn0.95O thin film annealed at 600°C exhibits the highest photocatalytic activity, degrading MO by almost 85.8% after 180min illumination. The photocatalytic activity of the thin film is a synergistic effect defined by grain size, roughness factor, oxygen defects and amorphous MgO.
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