Geotechnical monitoring data (e.g., settlement monitoring data) are often sparsely measured at limited locations, but the corresponding geotechnical quantities of interest (e.g., ground settlement) ...usually vary in both temporal and spatial dimensions. The sparsely measured monitoring data can be efficiently leveraged under a sparse dictionary learning (SDL) framework, which represents a spatio-temporally varying quantity (e.g., settlement) by a weighted summation of dictionary atoms. However, selection of dictionary atoms in SDL greatly affects the SDL performance, and under-fitting or over-fitting problems are frequently encountered, particularly when dealing with limited monitoring data. To tackle these problems, a knee point-based method is proposed in this study to properly select dictionary atoms for optimizing the SDL performance. The proposed method not only automatically determines dictionary atom IDs and weights, but also strikes a balance between the under-fitting and over-fitting. The proposed approach is illustrated using a real case history of embankments constructed on soft clay in Australia. The proposed approach significantly improves the prediction of time-varying settlements that also spatially vary over a two-dimensional (2D) space (e.g., a vertical cross-section), particularly at subsequent time steps and spatial locations without monitoring data. Effects of the dictionary atom quantity on settlement predictions are also investigated.
Photoactive two‐dimensional covalent organic frameworks (2D‐COFs) have become promising heterogenous photocatalysts in visible‐light‐driven organic transformations. Herein, a visible‐light‐driven ...selective aerobic oxidation of various small organic molecules by using 2D‐COFs as the photocatalyst was developed. In this protocol, due to the remarkable photocatalytic capability of hydrazone‐based 2D‐COF‐1 on molecular oxygen activation, a wide range of amides, quinolones, heterocyclic compounds, and sulfoxides were obtained with high efficiency and excellent functional group tolerance under very mild reaction conditions. Furthermore, benefiting from the inherent advantage of heterogenous photocatalysis, prominent sustainability and easy photocatalyst recyclability, a drug molecule (modafinil) and an oxidized mustard gas simulant (2‐chloroethyl ethyl sulfoxide) were selectively and easily obtained in scale‐up reactions. Mechanistic investigations were conducted using radical quenching experiments and in situ ESR spectroscopy, all corroborating the proposed role of 2D‐COF‐1 in photocatalytic cycle.
COFs in photocatalytic oxidation of organics: Hydrazone‐based 2D‐COF‐1 offers a fascinating alternative photocatalyst for visible‐light‐driven selective aerobic oxidation of valuable small organics such as amines, ethers, thioethers and pyridinium salts. By means of its superior photocatalytic ability in molecular oxygen activation and inherent heterogenous nature, the present protocol exhibits impressive efficiency, selectivity and sustainability.
A novel coronavirus severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) outbreak has caused a global coronavirus disease 2019 (COVID-19) pandemic, resulting in tens of thousands of ...infections and thousands of deaths worldwide. The RNA-dependent RNA polymerase (RdRp), also named nsp12 is the central component of coronaviral replication and transcription machinery, and it appears to be a primary target for the antiviral drug remdesivir. We report the cryo-electron microscopy structure of COVID-19 virus full-length nsp12 in complex with cofactors nsp7 and nsp8 at 2.9-angstrom resolution. In addition to the conserved architecture of the polymerase core of the viral polymerase family, nsp12 possesses a newly identified β-hairpin domain at its N terminus. A comparative analysis model shows how remdesivir binds to this polymerase. The structure provides a basis for the design of new antiviral therapeutics that target viral RdRp.
A simple, efficient and environmentally friendly method for iron or boron-catalyzed C-H arylthiation of substituted phenols at room temperature has been developed, and the corresponding diaryl ...sulfides were prepared in good to excellent yields. The protocol uses readily available 1-(substituted phenylthio)pyrrolidine-2,5-diones as the arylthiation reagents and inexpensive and environmentally friendly FeCl3 or BF3·OEt2 as the catalyst, moreover no ligands, additives or extrusion of air are required, and the reactions can be performed successfully at room temperature.
Abrupt drought–flood alternation (T1) is a meteorological disaster that frequently occurs during summer in southern China and the Yangtze river basin, often causing a significant loss of rice ...production. In this study, the response mechanism of yield decline under abrupt drought–flood alternation stress at the panicle differentiation stage was analyzed by looking at the metabolome, proteome as well as yield and physiological and biochemical indexes. The results showed that drought and flood stress caused a decrease in the yield of rice at the panicle differentiation stage, and abrupt drought–flood alternation stress created a synergistic effect for the reduction of yield. The main reason for the decrease of yield per plant under abrupt drought–flood alternation was the decrease of seed setting rate. Compared with CK0 (no drought and no flood), the net photosynthetic rate and soluble sugar content of T1 decreased significantly and its hydrogen peroxidase, superoxide dismutase, peroxidase activity increased significantly. The identified differential metabolites and differentially expressed proteins indicated that photosynthesis metabolism, energy metabolism pathway and reactive oxygen species response have changed strongly under abrupt drought–flood alteration stress, which are factors that leads to the rice grain yield reduction.
We aimed to explore the clinicopathological features and survival-related factors for intrahepatic cholangiocarcinoma (ICC). Eligible data were extracted from the Surveillance, Epidemiology and End ...Results (SEER) database from 2004 to 2015. Totally, 4595 ICC patients were collected with a male to female ratio of nearly 1:1. The higher proportion of ICC patients was elderly, tumor size ≥ 5 cm and advanced AJCC stage. Most patients (79.2%) have no surgery, while low proportion of patients receiving radiotherapy (15.1%). The median survival was 7.0 months (range 0-153 months). The 5-year CSS and OS rates were 8.96% and 7.90%. Multivariate analysis found that elderly age (aged ≥ 65 years old), male, diagnosis at 2008-2011, higher grade, tumor size ≥ 5 cm, and advanced AJCC stage were independent factors for poorer prognosis; while API/AI (American Indian/AK Native, Asian/Pacific Islander) race, married, chemotherapy, surgery and radiotherapy were independent favorable factors in both CSS and OS. Furthermore, stratified analysis found that chemotherapy and radiotherapy improved CSS and OS in patients without surgery. Age, sex, race, years of diagnosis, married status, grade, tumor size, AJCC stage, surgery, chemotherapy and radiotherapy were significantly related to prognosis of ICC. Chemotherapy and radiotherapy could significantly improve survival in patients without surgery.
Prediction of the regioselectivities ( i.e. , the active sites) of dearomatization reactions has been and continues to be one of the most challenging issues in the modern synthesis field. In this ...work, we provide a valuable case for predicting the origin of the chemoselectivity for organocatalyst-catalyzed asymmetric dearomatization (CADA) reactions. Herein, the possible mechanisms and the origin of selectivities of NHC-catalyzed asymmetric dearomatization reaction of isoquinoline have been systematically investigated using density functional theory (DFT) for the first time. Computational results show that the intermolecular Mannich-type transformation was both the stereoselectivity- and chemoselectivity-determining step. The NCI analysis reveals that C–H⋯Br and π⋯π interactions contribute significantly to the control of the stereoselectivity. Furthermore, the origin of regioselectivities on NHC-catalyzed asymmetric dearomatization reactions of other aromatic rings has been accurately predicted by performing the local reactivity index analysis. This work would provide valuable clues for predicting the origin of the selectivities and designing more effective organocatalysts for these kinds of reactions with high and special selectivities.
The prevalence of sarcopenia and its clinical predictors and clinical impact vary among kidney transplant recipients (KTRs), in part because of different diagnostic criteria. This study aimed to ...assess the reported diagnosis criteria of sarcopenia and compare them in terms of prevalence, clinical predictors, and impact of sarcopenia. The Medline, Embase, and Cochrane Library were searched for the full‐length reports published until 28 January 2022. The subgroup analysis, meta‐regression, and sensitivity analysis were performed and heterogeneity was assessed using the I2. A total of 681 studies were retrieved, among which only 23 studies (including 2535 subjects, 59.7% men, mean age 49.8 years) were eventually included in the final analysis. The pooled prevalence in these included studies was 26% 95% confidence interval (95% CI): 20–34%, I2 = 93.45%, including 22% (95% CI: 14–32%, I2 = 88.76%) in men and 27% (95% CI: 14–41%, I2 = 90.56%) in women (P = 0.554 between subgroups). The prevalence of sarcopenia diagnosed using low muscle mass was 34% (95% CI: 21–48%, I2 = 95.28%), and the prevalence of using low muscle mass in combination with low muscle strength and/or low physical performance was 21% (95% CI: 15–28%, I2 = 90.37%) (P = 0.08 between subgroups). In meta‐regression analyses, the mean age (regression coefficient: 1.001, 95% CI: 0.991–1.011) and percentage male (regression coefficient: 0.846, 95% CI: 0.367–1.950) could not predict the effect size. Lower body mass index (odds ratio (OR): 0.57, 95% CI: 0.39–0.84, I2 = 61.5%), female sex (OR: 0.31, 95% CI: 0.16–0.61, I2 = 0.0%), and higher age (OR: 1.08, 95% CI: 1.05–1.10, I2 = 10.1%) were significantly associated with a higher risk for sarcopenia in KTRs, but phase angle (OR: 0.81, 95% CI: 0.16–4.26, I2 = 84.5%) was not associated with sarcopenia in KTRs. Sarcopenia was not associated with rejections (risk ratio (RR): 0.67, 95% CI: 0.23–1.92, I2 = 12.1%), infections (RR: 1.03, 95% CI: 0.34–3.12, I2 = 87.4%), delayed graft functions (RR: 0.81, 95% CI: 0.46–1.43, I2 = 0.0%), and death (RR: 0.95, 95% CI: 0.32–2.82, I2 = 0.0%) in KRTs. Sarcopenia was found to be very common in KRTs. However, we have not found that sarcopenia had a negative impact on clinical health after kidney transplantation. Large study cohorts and multicentre longitudinal studies in the future are urgently needed to explore the prevalence and prognosis of sarcopenia in kidney transplant patients.
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•MNOP-H2S is highly sensitive to sense H2S with a detection limit of 29 nM.•MNOP-H2S can monitor mitochondrial basal H2S levels.•MNOP-H2S is applied for distinguishing cancer cells ...from normal cells.•MNOP-H2S is applied to verify role of H2S in endothelial cell migration.
Hydrogen sulfide (H2S) is recognized as a critical gaseous signaling molecule involved in multiple physiological and pathological processes. The important pathophysiological roles of H2S have spurred intense interest in developing fluorescent probes for imaging of H2S. Using a piperazidine-bridged styrylpyridinium as the push-pull fluorophore and a 7-nitro-1,2,3-benzoxadiazole moiety as the response group, herein we developed a mitochondria-targeted fluorescent probe MNOP-H2S, which exhibited remarkable fluorescence turn-on (>130 fold), large Stokes shift (190 nm), excellent sensitivity and selectivity. Importantly, the probe was characterized by an ultralow detection limit (29 nM), thereby being successfully applied to monitor mitochondrial basal H2S levels in various types of cells and zebrafish, to distinguish cancer cells from normal cells (even from each other) and to reveal that the endogenously produced H2S in mitochondria is a key mediator for the endothelial cell migration stimulated by vascular endothelial growth factor.
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•We proposed a low carbon multi-objective land use allocation optimization model.•The model is solved with an improved non-dominated sorting genetic algorithm-II.•Resulting optimal ...schemes significantly outperform the original land use plan.•Vector patch-based optimized schemes better support low-carbon land use plan.
The rational land use allocation is of great significance to the construction of low-carbon cities. The optimization model of land use allocation is an important tool that helps urban planners to quantitatively trade-off among the multi-objectives and achieve optimal land use schemes. For multi-objective optimization of low-carbon land use allocation, the models conducted by existing studies generally tend to be based on gridded data, lack of comprehensive consideration of quantitative and spatial objectives, and efficient algorithms to execute the optimization process. Therefore, this paper proposed a patch-based low carbon multi-objective land use allocation (LC-MLUA) optimization model involving both quantitative and spatial optimization targets. The LC-MLUA optimization model was solved with an improved non-dominated sorting genetic algorithm-II (NSGA-II), and the weighted-sum method was used to make the final selection under different preferences. The LC-MLUA optimization model was then applied to a case study of Changxing, a county-level city in east China, and there were three key results. (1) The LC-MLUA optimization model had a remarkable outperform of the land use allocation than the original land use plan, and the optimized values of economic benefit, emission reduction, and accessibility increased by 27.0%, 6.2% and 8.3%, respectively. (2) The LC-MLUA optimization model generated a series of optimal schemes to support suggestion-making for the low-carbon adjustment of the land use structure and spatial layout. (3) The LC-MLUA optimization model based on vector land patch data was proved more efficient as the unit number was reduced by 5 times than gridded data and better reflected the land use planning practice. (4) Compared with other algorithms, the improved NSGA-II had better performance in the number of solutions, target optimization rate, and comprehensive performance. Based on these results, it suggests that the patch-based LC-MLUA optimization model method can provide good technical support for low-carbon land use planning, and can be flexibly applied to other cities.
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