We report here a mechanochemical protocol for asymmetric cross‐dehydrogenative coupling (CDC) reaction of unreactive 3‐arylmethyl indoles with 1,3‐dicarbonyl by liquid‐assisted grinding. Small drops ...of liquid additive n‐butyl acetate (n‐BuOAc) are key to achieve high yield and enantioselectivity in this transformation. The catalyst can be lowered to 5 mol% and reused for three times. Pharmaceutical useful chiral dihydrocoumarins are further achieved through one‐pot tandem asymmetric CDC and cyclization with excellent enantioselectivities. Experimental and computational studies on the reaction mechanism suggest that n‐BuOAc is participated to the catalytic cycle, forming a chiral metal species during the reaction process and thereby revealed the origin of stereoselectivity.
•Potential evapotranspiration is different from reference crop evapotranspiration•The development histories of these two kinds of evapotranspirations are described•The equations for calculating these ...two kinds of evapotranspirations are listed•The difference between these two kinds of evapotranspirations are compared
Potential evapotranspiration (ETp) and reference crop evapotranspiration (ETo) differ in their developments, concepts, equations and application fields, however, many researchers have mixed the utilization of the two terms. Thus, it is necessary to clarify the terms to guide their proper usage. The aim of this study is to provide a comprehensive review of the concepts, developments, equations and applications of ETp and ETo. The review shows clearly that the concepts and developments of ETp and ETo have long histories. The original concept of ETp was proposed by Thornthwaite, and that core idea with various improvements has been used up to now. The development of ETo, although initially confused with that of ETp, was formally defined as a standard method. The ETp equations were classified as mass-transfer-based, temperature-based, radiation-based and combination types. While the ETo equations were classified as being temperature-based, radiation-based, combination and pan-evaporation-based. Both terms are connected to evaporation and evapotranspiration, and although there have been ambiguities, ETp has been applied mostly in hydrology, meteorology and climatology, while ETo has been applied mostly in agronomy, agriculture, irrigation and ecology. ETp has been used to estimate drought indices, and ETo has been used in the single and dual crop coefficient methods and the Shuttleworth-Wallace method for estimating actual field evapotranspiration. This review serves to clarify the origins, definitions, and uses of ETp and ETo. It addresses common ambiguities between the terms in order to aid the proper utilization of the terms.
Potential evapotranspiration (ETp) and reference crop evapotranspiration (ETo) are two key parameters in hydrology, meteorology, and agronomy. ETp and ETo are related to each other but have different ...meanings and applications. In this study, the ETp and ETo were distinguished and calculated with the Penman and FAO56 PM equations using the weather data of 551 stations in China from 1961 to 2018. The differences in their spatiotemporal variations were examined with an MMK test, an R/S test, and wavelet analysis. The monthly ETp and ETo were close but the ETp was always larger than the ETo, with values ranging from 1 to 356 mm and 2 to 323 mm, respectively. Their differences varied in different months and sub-regions. The maximum monthly difference transferred from south to north and then back to the south in a yearly cycle, showing spatiotemporal heterogeneity. The annual values of the ETp and ETo were also close, but the ETp was significantly higher than the ETo. The increasing future trends of ETp but decreasing trends of ETo were tested at most sites in China. Although the primary periods were almost the same, their spatial distribution was slightly different. In conclusion, ETp is different from ETo and they should be applied carefully. This study performs a thorough comparison and reveals the underlying basis of and discrepancy between ETp and ETo.
Alkenylbenzene skeletons represent one of the most widely occurring structural motifs in pharmaceutical drugs, natural products, and advanced materials. The construction of alkenylbenzenes is ...promising through the use of a straightforward oxidative alkenylation protocol, particularly from unactivated alkenes. This is significant because unactivated alkenes are inexpensive raw materials that can be obtained in bulk quantities from petrochemical feedstocks and renewable resources. However, controlling the reactivity and regioselectivity of olefination with unbiased olefins remains a significant challenge, necessitating continuous efforts and potentially having a substantial impact on both organic synthesis and the industry. This review aims to provide an overview of the latest advances in regiocontrol strategies for oxidative alkenylation reactions with unactivated alkenes, which can be categorized into three types: 1) ligand‐promoted/accelerated reactions; 2) prefunctionalized olefins‐facilitated reactions; 3) directing group‐induced reactions.
Growing inputs of microplastics into marine sediment have increased significantly the needs for assessment of their potential risks to the marine benthos. A knowledge gap remains with regard to the ...effect of microplastics on benthos, such as cephalochordates. By employing amphioxus as a model benthic chordate, here we show that exposure to microplastics for 96 h at doses of 1 mg/L and 100 mg/L results in evident accumulation of the polyethylene microplastics. The accumulated microplastics are as much as 0.027% of body weight upon high-dose exposure, causing an abnormal body-bending phenotype that limits the locomotion capability of amphioxus. Mechanistic insight reveals that microplastics can bring about histological damages in gill, intestine and hepatic cecum; In-depth assay of relevant biomarkers including superoxide dismutase, catalase, glutathione, pyruvic acid and total cholesterol indicates the occurrence of oxidative damage and metabolic disorder; Further, microplastics exposure depresses the activity of acetylcholinesterase while allowing the level of acetylcholine to rise in muscle, suggesting the emergence of neurotoxicity. These consequences eventually contribute to the muscle dysfunction of amphioxus. This study rationalizes the abnormal response of the vulnerable notochord to microplastics, signifying the dilemma suffered by the ancient lineage under the emerging threat. Given the enrichment of microplastics through marine food chains, this study also raises significant concerns on the impact of microplastics to other marine organisms, and eventually human beings.
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•Microplastics exposure can cause body-bending of amphioxus even if it stays still.•The abnormal bending arises from muscle dysfunction caused by neurotoxicity.•The limited capability of movement puts the ancient lineage to a dilemma.•It fills the knowledge gap on the risk of microplastics to the transitional species.
A risk-based approach is more meaningful to quantify the effects of drought on crop yield given the randomness nature of past drought events, compared to the deterministic approach. However, the ...majority of these probabilistic studies are conducted at national or global scale to assess the yield loss probability under given drought conditions. There is still a lack of research combining droughts and crop yields in a probabilistic way at a local scale. Moreover, it is unclear how drought threshold triggering yield loss at a given conditional probability will vary in dryland cropping regions. Here, we used wheat yield data from 66 shires in New South Wales (NSW) wheat belt and meteorological data from 986 weather stations. A copula-based probabilistic method was developed to explore the yield loss probability to various drought conditions. We investigated the drought threshold under a given yield loss probability using the constructed copula function. We found that SPEI-6 in October was the optimal drought index to represent detrended wheat yield variation as this period covered the main growth stages of winter wheat in the study region. Our results show that as the severity of drought increased, the wheat yield loss probability also increased. Yield loss probability varied among the study shires, mainly due to the various climate conditions of each region. The drought threshold in subregion 1 (the northwest) was highest, followed by subregion 2 (the southwest) and subregion 3 (the eastern), indicating that wheat yield in subregion 1 was more sensitive to drought. The findings could provide important direction and benchmarks for stakeholders in evaluating the agricultural impact of drought, especially in those drought prone areas. We expect that the methodological framework developed here can be extended to other dryland areas to provide helpful information to growers, risk management policy makers and agricultural insurance evaluators.
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•Wheat yield failure risk under drought conditions is quantified using copula functions in southeastern Australia.•Yield loss probabilities under drought conditions are much higher than those under non-drought conditions.•Western region in the study area is more vulnerable to drought than eastern region.•Drought thresholds vary across regions due to variable climate.
Poor management and disposal of plastic materials and the accumulation of microplatics in the environment and foods are an issue of increasing public concern. The current understanding of the ...implications of microplastics for human health has been limited to the bioeffect of individual exposure. In the bigger view of microplastic contamination, however, toxic compounds, including antibiotics, harbored on active microplastics can be collectively transported through food chains, raising questions about the effect of their combined exposure on human health. By employing a mouse model for human physiology, we discovered that a concurrent exposure to the major types of antibiotics and microplastics, namely sulfamethoxazole (SMZ) and polystyrene microplastics, respectively, would result in evident accumulation in detoxification organs; specifically, liver could amass 41.70 μg kg
of SMZ, while 3.83% of microplastics was accumulated in the kidney. Insights into the occurrence of liver histopathological changes (
, amyloidosis and necrocytosis) revealed that compared with the individual treatment of SMZ, treatment by microplastic-contaminated SMZ elicited increases in the levels of malonaldehyde and NF-κβ by 174% and 104%, respectively; while the activities of antioxidases investigated were depressed by up to 22% upon co-exposure. It is suggested that SMZ enriched on active microplastic surfaces causes enhanced hepatic damage. Profiling of the gene expression clarified the correlation of the exacerbated oxidative and inflammatory damages in the liver with the overexpression of
to dysregulate the
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pathway. This study acts as a reminder about the complexity of contamination and raises awareness of health issues that microplastics could cause public health through liver diseases.
Funding inputs and research outputs have always been two central issues in the science of science. In recent decades, research funding plays an increasingly important role in scientific research. ...Thus, it is progressively significant for management authorities to measure the research efficiency of highly funded scientists, which can be helpful for them to make effective policies. However, few researchers use quantitative analysis to study these issues. To promote the research in this field, we begin with collecting a dataset. This dataset contains research funding and other information from 345 highly funded scientists in Mainland China. Next, we use the dataset to measure the efficiency of highly funded scientists based on the data envelopment analysis. In this way, highly funded scientists are placed into several levels according to their research inputs and outputs. We also give their attractiveness and progress scores compared to other grades. The learning path for less efficient scientists is also provided. We find that highly funded scientists have relatively high efficiency in three kinds of projects, such as the Major Research Plan. Besides, the career length and career start year are demonstrated to have a limited impact on the highly funded scientists. These patterns are beneficial for the development of the scientific community and management authorities to make policies.
Early protein 0 (EP0) is especially important for modulating PRV gene expression and reactivation from the latent state, but the mechanisms have not been elucidated. In this study, six monoclonal ...antibodies (MAbs) against EP0 protein of PRV were generated and their characterizations were investigated. Western blot analysis showed all six MAbs could react with immunizing antigen, but only 2B12 and 2C6 could react with native EP0 protein from PRV-infected cells. ELISA additivity tests revealed that at least three epitopes in EP0 were defined by six MAbs. The epitope recognized by MAb 2B12 was further identified in 287-292 aa of EP0 protein using a series of expressed overlapping peptides. These MAbs may provide valuable tools for further research of the functions of EP0 in PRV infection.
Since the competition in the scientific community is becoming increasingly fierce, measuring the research performance of highly funded scientists is growingly critical for relevant management ...authorities to make effective policies in scientific research and development. However, little quantitative analysis has focused on this issue. To facilitate the research in this area, we first construct a dataset containing both the funding inputs and the research paper outputs of highly funded scientists in China. Then, instead of directly summing quantitative indicators, in this paper, we measure the efficiency of highly funded scientists in China based on the data envelopment analysis models. We show that we can grade highly funded scientists into several grades and present their scores on attractiveness or progress to other grades. The gradual learning path for less efficient scientists is also provided. These patterns of highly funded scientists may be beneficial for management authorities to make effective policies.
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