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A series of spiro-phosphonium compounds have been synthesized by copper-mediated coupling reaction of phosphacyclic compounds with alkynes. Their photophysical properties are tuned by varying substituents and exhibit different luminescent colors from blue to green, and finally, yellow. The fluorescence quantum efficiency of diethyl spiro-xanthenebenzophosphole 3aa in solid and liquid states reached 31% and 76%, respectively. Diphenyl spiro-xanthenebenzophosphole 3ad displayed relatively low cytotoxicity toward lung cancer cells A549 and was able to effectively penetrate the cell membrane and maintain strong staining. Moreover, density functional theory (DFT) and time-dependent DFT calculations have been performed to explore the origin of their photophysical properties.

Phosphaphenalenes, extended π conjugates with the incorporation of phosphorus, are attractive avenues towards molecular materials for the applications in organic electronics, but their electron accepting ability have not been investigated. Herein we present systematic studies on the reductive behavior of a representative phosphaphenalene and its oxide by chemical and electrochemical methods. The chemical reduction of the phosphaphenalene by alkali metals reveals the facile P-C bond cleavage to form phosphaphenalenide anion, which functions as a transfer block for structure modification on the phosphorus atom. In contrast, the pentavalent P-oxide reacts with one or two equivalents of elemental sodium to form stable radical anion and dianion salts, respectively., (© 2024 Wiley-VCH GmbH.)

Ecological drought is a complex process in terrestrial ecosystems where vegetation's eco-physiological functions are impaired due to water stress. However, there is currently a lack of long-term assessment of ecological drought from an eco-physiological perspective. In this study, the standardized ecological drought index (SESNDI) was developed using actual evaporation, root soil moisture, and kernel normalized difference vegetation index via the Euclidean distance method, reflecting ecosystem physiology, water supply capacity, and vegetation status. Solar-induced chlorophyll fluorescence validated SESNDI by reflecting vegetation photosynthesis. Using China as an example, severely impacted by climate change and ecological restoration, ecological drought's spatio-temporal variation and propagation characteristics was evaluated using clustering algorithms. The results demonstrated that (1) SESNDI showed superior performance over several other drought indices. (2) During 1982-2020, ecological drought was prevalent from 1990 to 2010, especially in the central and northeastern regions. (3) Compared to 1982-2000, the median duration and affected area of ecological drought events during 2001-2020 reduced by four months and 1.51 × 10 5  km 2 , respectively, while the median intensity increased by 0.06. (4) Decreased precipitation and increased temperature were the primary factors contributing to the frequent occurrence of ecological drought in China from 1990 to 2010. This study offers a crucial methodology for evaluating ecological drought, serving as a reference for developing effective terrestrial restoration strategies., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024. Published by Elsevier B.V.)

Background: The genus of Polypedates Tschudi, 1838 currently comprises 25 recognised species with four of these species reported in Yunnan, China. Dubois (1987) speculated the distribution of P.teraiensis in China; however, there was no study carried out to confirm its distribution in the region., New Information: We herein describe P.teraiensis as a new national record, based on a specimen collected from Yunnan border region. Phylogenetically, our sequence clustered with the sequences of recognised P.teraiensis specimens from Bangladesh, Myanmar and India. The uncorrected pairwise distances between the specimens from China and other P.teraiensis localities was small, ranging from 0.0-0.7%, based on 16S rRNA gene. Therefore, we report P.teraiensis as a new species record for China., (Zhong-Bin Yu, Felista Kasyoka Kilunda, Kai Wang, Yu-Yang Cao, Chun-Lian Wu, Zheng-Pan Duan, Chang-Sheng Zuo, Ding-Can Zhang, Yun-He Wu, Jing Che.)

Cities, where human energy activities and greenhouse gas emissions are concentrated, contribute significantly to alleviating the impacts of global climate change. Utilizing the China Carbon Emissions Accounting Database (CEADs) to provide carbon dioxide emission inventories for urban areas in China at the prefecture level, this study closely examines the historical evolution trajectories of carbon emissions across 247 urban units from 2005 to 2019. The logarithmic cubic function model was employed to simulate these trajectories, evaluating urban emission peaks and classifying the different carbon emission trajectories. Further, the Geographical and Temporal Weighted Regression model was employed to explore spatiotemporal traits and essential variables that impact the variations in carbon emissions among four identified trajectory types. Our results showed that Chinese urban carbon emission trajectories can be classified into four categories: a) peaking emissions, b) fluctuating growth, c) continuous growth, and d) passive decline. Specifically, 43 cities, primarily in North China, proactively attained their emission peak post-2010, driven by the reduction in secondary industry and energy intensity. 90 cities, largely industrial hubs in the southeast coast and inland, reached an emission plateau around 2015, exhibiting fluctuating growth due to dependencies on secondary industries. 101 cities, predominantly located in western and central regions, demonstrated a clear upward trend in carbon emissions, propelled by rapid urbanization and heavy industry-oriented economic development. Lastly, 13 cities, typically in the northeastern and southwestern regions, experienced a passive decline in carbon emissions, attributable to resource depletion or economic downturns. It is evident that China's city-level carbon peaking has demonstrated some effectiveness, yet considerable progress is still required., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hypergolicity is a highly desired characteristic for hybrid rocket engine-based fuels because it eliminates the need for a separate ignition system. Introducing hypergolic additives into conventional fuels through physical mixing is a feasible approach, but achieving highly reliable hypergolic ignition and energy release remains a major challenge. Here, the construction of core-shell Al@metal organic framework (MOF) heterostructures is reported as high-performance solid hypergolic propellants. Upon contact with the liquid oxidizer the uniformly distributed hypergolic MOF (Ag-MOF) shell can induce the ignition of hypergolic-inert fuel Al, resulting in Al combustion. Such a synthetic strategy is demonstrated to be favorable in hotspot generation and heat transfer relative to a simple physical mixture of Al/Ag-MOF, thus producing shorter ignition delay times and more efficient combustion. Thermal reactivity study indicated that the functionalization of the Ag-MOF shell changes the energy release process of the inner Al, which is accompanied by a thermite reaction. The synergistic effect of implantation of hypergolic MOF and high energy Al contributes to high specific impulses of 230-270 s over a wide range of oxidizer-to-fuel ratios., (© 2024 Wiley‐VCH GmbH.)

This study compared two different methods, the satellite altimetry-based and DEM (digital elevation model)-based, for estimating lake water volume changes. We focused on 34 lakes in China as the testing sites to compare the two methods for lake water volume changes from 2005 to 2020. The satellite altimetry-based method used water levels provided by the DAHITI (Database for Hydrological Time Series of Inland Waters) data and surface areas derived from Landsat imagery. The DEM-based method used the SRTM DEM data in combination with Landsat-derived lake extents. Our results showed a high degree of consistency in lake water volume changes estimated between the two methods ( R 2 > 0.90), but each method has its limitations. In terms of temporal coverage, the satellite altimetry-based method with the DAHITI data is limited by missing water level data in certain periods. The performance of the DEM-based method in extracting lake shore boundaries in regions with flat terrains (slope <1.5°) is not satisfactory. The DEM-based method has complete regional applicability (100%) in the Tibetan Plateau (TP) Lake Region, yet its effectiveness drops significantly in the Xinjiang and Eastern China Plain Lake Regions, with applicability rates of 50 and 40%, respectively ., Competing Interests: The authors declare there is no conflict., (© 2024 The Authors This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).)

Herein, we report an efficient and straightforward approach for the synthesis of N -alkylated aminoquinoline derivatives by recyclable Cd-containing coordination polymer-catalyzed reactions of aminoquinolines with primary alcohols via the borrowing hydrogen strategy. In this work, a new type of coordination polymer [Cd(CIA)(phen) 2 (H 2 O)] n was successfully designed and fabricated. The molecular structure was corroborated by single-crystal X-ray diffraction and fully characterized by PXRD, FT-IR, TGA, and XPS. Importantly, this polymer revealed high catalytic activity for the N -alkylation reaction of 2-aminoquinoline and 8-aminoquinoline with inexpensive and low-toxicity alcohols as alkylating agents in excellent yields up to 95%. Interestingly, the present synthetic protocol was successfully applied for the gram-level synthesis of several biologically active compounds. In addition, several control reactions were carried out to investigate the possible mechanisms of this transformation. Finally, recycling experiments indicated that the cadmium coordination polymer showed good recovery performance for borrowing hydrogen reactions.

Ring expansion of strained small rings provides an efficient method for the synthesis of various high-value carbocycles and heterocycles. Here we report BF 3 ·Et 2 O as both an activating reagent and fluorine source, enabling ring expansion of phosphirane and P-F bond formation. Treatment of 1-iminylphosphirane complexes with BF 3 ·Et 2 O resulted in 1,2-azaphospholidines, while the reaction of 1-acylphosphirane complexes with BF 3 ·Et 2 O afforded 1,2-dihydrophosphetes. The reaction path was tuned by the nucleophilicity of the N and O atoms toward the intermediate phosphenium cation.

Herein, we describe how computational mechanistic understanding has led directly to the discovery of new 2H-phosphindole for C-C Ar bond activation and dearomatization reaction. We uncover an unexpected intramolecular C-H bond activation with a 2H-phosphindole derivative. This new intriguing experimental observation and further theoretical studies led to an extension of the reaction mechanism with 2H-phosphindole. Through DFT calculations, we confirm that within a five-membered ring, the polarizable PC 3 unit orchestrates the formation of an electrophilic phosphorus atom (P + ) and a nucleophilic carbon atom (C - ). This kinetically accessible ambiphilic phosphorus/carbon couple is spatially separated by geometric constraints, and their reactivity is modulated through structural resonance., (© 2023 Wiley-VCH GmbH.)

Cyclodimerization of readily accessible acetylenic ketones facilitated by a phosphane-borane complex under basic conditions is achieved. This methodology allows one-pot synthesis of phosphorus-involved tetrasubstituted furans via the construction of a C-P bond and a furan ring within a single procedure. A plausible reaction mechanism is proposed.

The heavier main group multiple bonds offer an effective tool for small molecule activation. Transient 2H-phosphinidole working as a reactive phosphadiene system undergoes phospha-Diels-Alder reaction with a wide range of non-activated aromatic carbocycles and heterocycles, including naphthalene, anthracene, phenanthrene, furan, thiophene, pyrrole, pyridine, and benzo-fused heterocycles, affording concise access to a range of polycyclic fused rings feature with phosphorus at the bridgehead. These results demonstrate that non-activated (hetero)arenes are capable of acting as 2π systems in [4+2] cycloaddition with highly reactive 2H-phosphindole complex., (© 2023 Wiley-VCH GmbH.)

River transport of dissolved organic carbon (DOC) to the ocean is a crucial but poorly quantified regional carbon cycle component. Large uncertainties remaining on the riverine DOC export from China, as well as its trend and drivers of change, have challenged the reconciliation between atmosphere-based and land-based estimates of China's land carbon sink. Here, we harmonized a large database of riverine in-situ measurements and applied a random forest model, to quantify riverine DOC fluxes (F DOC ) and DOC concentrations (C DOC ) in rivers across China. This study proposes the first DOC modeling effort capable of reproducing well the magnitude of riverine C DOC and F DOC , as well as its trends, on a monthly scale and with a much wider spatial distribution over China compared to previous studies that mainly focused on annual-scale estimates and large rivers. Results show that over the period 2001-2015, the average C DOC was 2.25 ± 0.45 mg/L and average F DOC was 4.04 ± 1.02 Tg/year. Simultaneously, we found a significant increase in F DOC (+0.044 Tg/year 2 , p = .01), but little change in C DOC (-0.001 mg/L/year, p > .10). Although the trend in C DOC is not significant at the country scale, it is significantly increasing in the Yangtze River Basin and Huaihe River Basin (0.005 and 0.013 mg/L/year, p < .05) while significantly decreasing in the Yellow River Basin and Southwest Rivers Basin (-0.043 and -0.014 mg/L/year, p = .01). Changes in hydrology, play a stronger role than direct impacts of anthropogenic activities in determining the spatio-temporal variability of F DOC and C DOC across China. However, and in contrast with other basins, the significant increase in C DOC in the Yangtze River Basin and Huaihe River Basin is attributable to direct anthropogenic activities. Given the dominance of hydrology in driving F DOC , the increase in F DOC is likely to continue under the projected increase in river discharge over China resulting from a future wetter climate., (© 2023 John Wiley & Sons Ltd.)

A new class of phosphorus-doped triptycenes was designed and synthesized via a Diels-Alder reaction between alkynylphosphonates and anthracene, followed by oxidative cyclization. The packing interaction and molecular alignment in the single crystals revealed that the weak C-H⋯π (2.825 Å) interaction guides the self-assembly of phosphindole oxide iptycenes. The photophysical and electrochemical properties of these photoluminescent phosphorus-doped iptycenes were characterized to gain a deeper understanding of their fluorescence tunability. The presence of functional groups on the phenyl ring of the P-doped fin and the chemical environment of the P atom both had an effect on the fluorescence emission.

Fentanyl is widely used for anesthesia and analgesia in cancer patients. Recent studies have revealed its anti-growth effect in several categories of cancer. Gliomas are the most common primary tumors in the central nervous system with poor prognosis. To investigate the effects of fentanyl on gliomas, glioma cells were treated with different concentrations of fentanyl both in vitro and in vivo. Consequences of proliferation and invasive phenotypes, and related protein expression were evaluated in two human glioma cell lines (U251 and U87). Naloxone, Mu Opioid Receptor (MOR) antagonist, was introduced into culture media to assess the involvement of MOR in Fentanyl-mediated changes. When compared with control group, it could be found that Fentanyl inhibited function of glioma cells only at high concentrations. Western blot and immunofluorescence results revealed that Fentanyl exerted its action via modulating NF-κB (P65) activation which is likely independent of MOR. Moreover, overexpression of P65 by transfection P65-expressing vector restored the invasion and migration of glioma cells, which were inhibited by Fentanyl. In summary, this study showed that opioid pain medication Fentanyl was capable of decreasing invasiveness of glioma cells at a high concentration both in vitro and in vivo, likely via modulating P65 activation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Objective To clarify the effect and mechanism of tumor antigen-loaded dendritic cells (Ag-DCs) combined with cytokine-induced killers (CIKs) on the killing of esophageal cancer tumor cells. Methods Peripheral blood DCs and CIKs were induced and cultured, and the DCs were loaded with tumor antigen to obtain Ag-DCs, and Ag-DCs were co-cultured with CIKs. The experiment was divided into CIK group, DC combined with CIK group, Ag-DC combined with CIK group. Flow cytometry was used to detect the phenotype of cells. MTT assay was employed to determine the killing activity against EC9706 cells. Annexin V-FITC/PI double staining was used to detect the apoptosis rate of cells, immunofluorescence staining to detect the expression of phosphorylated apoptotic signal-regulated kinase 1 (p-ASK1) and Western blot analysis to detect the expression of ASK1 pathway related proteins. A nude mouse model of esophageal cancer transplantation tumor was constructed and divided into control group, DC combined with CIK group and Ag-DC combined with CIK group. The corresponding immune cells were injected into the tail vein for treatment and the tumor volume was measured every 2 days. After 21 days, all nude mice were sacrificed with the tumors taken out. HE staining was used to observe the tumor pathological changes and immunohistochemical staining was performed to detect the expression of ki67 and ASK1 in the tumor tissue. Results Comparedwith the CIK group alone and the DC combined with CIK group, the ratio of CD3 + CD8 + and CD3 + CD56 + in the cells significantly increased after Ag-DCs and CIKs co-culture, along with the increased killing rate of EC9706 cells, increased apoptosis rate of EC9706 cells, and the improved activation level of ASK1. Compared with the CIK group and the DC combined with CIK group, the growth of the transplanted tumor in nude mice treated with Ag-DCs combined with CIKs was significantly inhibited, and after 21 days, it was observed that the tumor tissue mass in this group was relatively smaller, with sparsely arranged cells in the tumor tissue and a decline in the positive rate of ki67 in tumor tissue, while the positive rate of ASK1 was significantly increased. Conclusion Co-cultivation of tumor antigen-loaded DCs with CIKs can significantly increase the killing activity of esophageal cancer tumor cells. The mechanism of action may be related to the activation of the ASK1 pathway.

Recent rapid warming has caused uneven impacts on the composition, structure, and functioning of northern ecosystems. It remains unknown how climatic drivers control linear and non-linear trends in ecosystem productivity. Based on a plant phenology index (PPI) product at a spatial resolution of 0.05° over 2000-2018, we used an automated polynomial fitting scheme to detect and characterize trend types (i.e., polynomial trends and no-trends) in the yearly-integrated PPI (PPI INT ) for northern (> 30°N) ecosystems and their dependence on climatic drivers and ecosystem types. The averaged slope for the linear trends (p < 0.05) of PPI INT was positive across all the ecosystems, among which deciduous broadleaved forests and evergreen needle-leaved forests (ENF) showed the highest and lowest mean slopes, respectively. More than 50% of the pixels in ENF, arctic and boreal shrublands, and permanent wetlands (PW) had linear trends. A large fraction of PW also showed quadratic and cubic trends. These trend patterns agreed well with estimates of global vegetation productivity based on solar-induced chlorophyll fluorescence. Across all the biomes, PPI INT in pixels with linear trends showed lower mean values and higher partial correlation coefficients with temperature or precipitation than in pixels without linear trends. Overall, our study revealed the emergence of latitudinal convergence and divergence in climatic controls on the linear and non-linear trends of PPI INT , implying that northern shifts of vegetation and climate change may potentially increase the non-linear nature of climatic controls on ecosystem productivity. These results can improve our understanding and prediction of climate-induced changes in plant phenology and productivity and facilitate sustainable management of ecosystems by accounting for their resilience and vulnerability to future climate change., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Wumei Wan (WMW) has been used to address digestive disorder for centuries in traditional Chinese medicine. Previous studies have demonstrated its anti-colitis efficacy, but the underlying mechanism of its action remains to be further clarified., Purpose: To investigate the underlying mechanisms of WMW in the treatment of chronic ulcerative colitis (UC) through network pharmacology and experimental validation., Methods: Traditional Chinese Medicine Systems Pharmacology (TCMSP) platform were used to identify the ingredients and potential targets of WMW. The microarray gene data GSE75214 datasets from GEO database was used to define UC-associated targets. Cytoscape3.7.2 was employed to construct the protein-protein interaction (PPI) network and compounds-disease targets network. GO enrichment analysis and KEGG pathway analysis were performed by R software for functional annotation. UPLC-TOF-MS/MS method was used to quantitatively analyze the active ingredients of WMW. For experimental validation, three cycles of 2% dextran sulfate sodium salt (DSS) were used to construct chronic colitis model. The hub targets and signal pathway were detected by qPCR, ELISA, western blotting , immunohistochemical and immunofluorescence., Results: Through network analysis, 104 active ingredients were obtained from WMW, and 47 of these ingredients had potential targets for UC. A total of 41 potential targets of WMW and 13 hub targets were identified. KEGG analysis showed that WMW involved in advanced glycation end products-receptor of advanced glycation end products (AGE-RAGE) signaling pathway. Taxifolin, rutaecarpine, kaempferol, quercetin, and luteolin of WMW were the more highly predictive components related to the AGE-RAGE signaling pathway. In vivo validation, WMW improved DSS-induced colitis, reduced the expression of inflammatory cytokines and chemokines. Notably, it significantly decreased the mRNA expression of Spp1, Serpine1, Mmp2, Mmp9, Ptgs2, Nos2, Kdr and Icam1, which were associated with angiogenesis. In addition, we confirmed WMW inhibited RAGE expression and diminished DSS-induced epithelial barrier alterations CONCLUSION: Our results initially demonstrated the effective components and the strong anti-angiogenic activity of WMW in experimental chronic colitis. Sufficient evidence of the satisfactory anti-colitis action of WMW was verified in this study, suggesting its potential as a quite prospective agent for the therapy of UC., Competing Interests: Declaration of Competing Interest We confirmed that there are no conflicts of interest related to this publication. There was no significant financial support for this work that may influence its outcome., (Copyright © 2023 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Dissolved Organic Carbon (DOC) in inland waters plays an essential role in the global carbon cycle and has significant public health effects. Machine learning (ML) together with remote sensing has emerged as a powerful and promising combination to quantify water quality parameters from space. However, inland water sample data for DOC is limited. Hence, little is known about the potential to quantify DOC content in inland waters, especially over large-scale areas. This study presents the first attempt to estimate DOC in inland waters over a large-scale area using satellite data and ML methods with the newly published open-source dataset AquaSat. Four ML approaches, namely Random Forest Regression (RFR), Support Vector Regression (SVR), Gaussian Process Regression (GPR), and a Multilayer Backpropagation Neural Network (MBPNN) were trained using more than 16 thousand samples across the continental United States matched with satellite data from Landsat 5, 7 and 8 missions. Satellite data from the Landsat missions were further extended with environmental data from the ERA5-Land product and used as input to train the ML algorithms. Our results show that including environmental data as inputs considerably improved the prediction of DOC for all ML algorithms, with GPR showing the most promising performance results with moderate estimation errors (RMSE: 4.08 mg/L). Permutation feature importance analysis showed that the wavelength range in the visible Green band (from Landsat) and the monthly average air temperature (from ERA5-Land) were the most important variables for the ML approaches. The results demonstrate the predictive strength of GPR and its useful feature to derive per pixel standard deviations for detailed analysis. Our results further highlight the important role of considering environmental processes to explain DOC variations over large scales. The application and performance of the GPR in mapping spatiotemporal variations of DOC in an entire water body were discussed by taking Lake Okeechobee (the 8 th largest freshwater lake in the U.S.) as an illustrative example. While performance evaluation showed that DOC concentrations can be retrieved with adequate accuracy, algorithm development was challenged by the heterogenous nature of large-scale open source in situ data, issues related to atmospheric correction, and the low spatial and temporal resolution of the environmental predictors. This research demonstrates how open source, large-scale datasets like AquaSat in combination with ML and satellite remote sensing can make research toward large-scale estimation of inland water DOC more realistic while highlighting its remaining limitations and challenges., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Ltd.)

Phosphenium ions [R 2 P] + are important and highly reactive dicoordinate phosphorus species. Herein, we report a rearrangement of the carbocation into the phosphenium cation driven by ring strain. This phosphorus-involved Wagner-Meerwein rearrangement pathway converted the 1-acylphosphirane complex into phosphetane and 1,2-dihydrophosphete derivatives depending on the reaction temperature. The generation of the intermediate phosphenium cation was identified by the intramolecular reaction with ether, which also disclosed its strong Lewis acidity. This work expands the boundary of the phosphorus-carbon analogy.

We developed novel shackled P-chiral ligands based on 1-phosphanorbornenes and oxazolines. They were subsequently evaluated in palladium-catalyzed (4+2) annulations, producing enantioenriched tetrahydropyran scaffolds in good yields with high site selectivity and enantioselectivity. Moreover, chemoselective (4+4) products were also achieved by using acyclic imines. In addition, density functional theory calculations were performed to afford the energy profile of the Michael addition step and ring formation step. This demonstrated that the enantioselective (4+2) annulations and the chemoselective reaction between (4+2) and (4+4) products were mostly under thermodynamic control.

With the development of large low earth orbit (LEO) communication constellations, the efficiency of laser inter-satellite link (ISL) establishing become the bottleneck for subsequent large-scale launch and rapid networking applications of LEO communication constellations. Hence, we establish the pointing jitter error structure of LEO communication experiment satellites (LCES) system. The error structure can be used to trace the source of errors and evaluate the in-orbit jitter. And we derive an analytical expression of the acquisition probability density function (PDF) which comprehensively considering the influence of the scanning region, the pointing jitter error, the overlap factor and the in-orbit jitter error. The multi-parameter influenced acquisition model is validated by Monte Carlo (MC) simulations and semi-physical tests. The results reveals that the multi-parameter influenced acquisition model can be used to guide the in-orbit ISL establishing.

Three series new NH 2 -benzophosphole oxides were synthesized from cycloaddition of o -aminophenyl phosphine oxide with alkynes. The relationship between the location of the amino group and the photophysical properties were studied by absorption and emission spectroscopies and theoretical calculation. 4-NH 2 -benzophosphole oxides show strong fluorescence emission and high fluorescence quantum efficiency. This "One stone three birds" process provides rapid access to multiple organophosphorus-based luminogens for the structure-property relationship study.

The activation of CS 2 by the 2 H -phosphindole complex with a low-coordinate phosphadiene moiety is reported. The successive hetero-Diels-Alder reaction between 2 H -phosphindoles and CS 2 constructs two bridged rings and one spirocycle simultaneously, affording structurally complex P,S-polycyclic products. The two 2 H -phosphindoles approach the C═S bond in a head-to-head disposition to minimize steric hindrance. This work reveals the unique reactivity of low-coordinate organophosphorus species and their potential applications in small molecule activation.

Intervertebral disc degeneration (IVDD) is the most common contributor to low back pain (LBP). Recent studies have found that oxidative stress and reactive oxygen species (ROS) play an important role in IVDD. As a by-product of aerobic respiration, ROS is mainly produced in the mitochondria by the electron transport chain and other mitochondrial located proteins. With the excessive accumulation of ROS, mitochondria are also the primary target of ROS attack in disc cells. A disrupted balance between intracellular ROS production and antioxidant capacity will lead to oxidative stress, which is the key contributor to cell apoptosis, cell senescence, excessive autophagy, and mitochondrial dysfunction. As the pivotal ingredient of oxidative stress, mitochondrial dysfunction manifests as imbalanced mitochondrial dynamics and dysregulated mitophagy. Mitochondria can alter their own dynamics through the process of fusion and fission, so that disabled mitochondria can be separated from the mitochondrial pool. Moreover, mitophagy participates by clearing these dysfunctional mitochondria. Abnormality in any of these processes either increases the production or decreases the clearance of ROS, leading to a vicious cycle that results in the death of intervertebral disc cells in large quantities, combined with degradation of the extracellular matrix and overproduction of matrix metalloproteinase. In this review, we explain the changes in mitochondrial morphology and function during oxidative stress-mediated IVDD and highlight the important role of mitochondria in this process. Eventually, we summarize the IVDD therapeutic strategies targeting mitochondrial dysfunction based on current understanding of the role of oxidative stress in IVDD., (© 2022 The Authors. Orthopaedic Surgery published by Tianjin Hospital and John Wiley & Sons Australia, Ltd.)

Dearomatization reactions have recently emerged as a powerful tool for the rapid buildup of molecular complexity. Here, an unparalleled thermal dearomatization [4+2] cycloaddition reaction between benzene derivatives and a 2 H -phosphindole tungsten complex was reported. The unique reactivity of the in situ -generated 2 H -phosphindole complex toward benzene was revealed by density functional theory calculations. We thus provide new insights into the dearomatization of nonactivated arenes and pave the way for the manipulation of the dearomatization for further applications.

The most fundamental tasks in asymmetric synthesis are the development of fully stereodivergent strategies to access the full complement of stereoisomers of products bearing multiple stereocenters. Although great progress has been made in the past few decades, developing general and practical strategies that allow selective generation of any diastereomer of a reaction product bearing multiple stereocentres through switching distinct chiral catalysts is a significant challenge. Here, attaining precise switching of the product stereochemistry, we develop a novel P -chirogenic ligand, i.e. YuePhos, which can be easily derived from inexpensive and commercially available starting materials in four chemical operations. Through switching of three chiral ligands, an unprecedented ligand-dependent diastereodivergent Pd-catalyzed asymmetric intermolecular [4 + 2] cycloaddition reaction of vinyl benzoxazinanone with α-arylidene succinimides was developed. This novel method provides an efficient route for the stereodivergent synthesis of six stereoisomers of pyrrolidines bearing up to three adjacent stereocenters (one quaternary center). Despite the anticipated challenges associated with controlling stereoselectivity in such a complex system, the products are obtained in enantiomeric excesses ranging up to 98% ee. In addition, the synthetic utilities of optically active hexahydrocarbazoles are also shown., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

One way of reducing environmental pollution is to reduce our dependence on fossil fuels by replacing them with solar radiation (Rs), which is one of the main sources of clean and renewable energy. In this study, daily Rs values at seven meteorological stations in Iran (Ahvaz, Isfahan, Kermanshah, Mashhad, Bandar Abbas, Kerman and Tabriz) over 2010-2019 were estimated using empirical models, support vector machine (SVM), SVM coupled with cuckoo search algorithm (SVM-CSA) and multi-model approach in the form of two structures. In structure 1, data from each station were divided into training and testing sets. In structure 2, data from the former four stations were used for model training, and those from the latter three stations were used to test the models. The results showed that using meteorological parameters improved estimation accuracy compared with the use of geographical parameters for both SVM and SVM-CSA models. Coupling the CSA to SVM did improve the accuracy of radiation estimates, reducing RMSE by up to 38% (Kermanshah station) and 36% (Tabriz station) for the first structure and about 42.4% (Tabriz station) for the second. Performance analysis of the models over three intervals including, the first, middle and last third of measured radiation values at each station showed that for both structures (except at Tabriz station), the best model performance in under- and over-estimation sets of radiation values was obtained, respectively, in the first third interval (first structure, Mashhad station, RMSE = 28.39 J.cm -2 .day -1 ) and the last third interval (first structure, Bandar Abbas station, RMSE = 12.23 J.cm -2 .day -1 ). Determining the effects of climate change on Rs estimation and using remotely sensed data as inputs of the models could be considered as future works., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A divergent intramolecular phosphination of alkynes is developed. Fine tuning of chemo- and regioselectivity has been realized by just adding LiBr or H 2 O to give 5- exo -dig and 6- endo -dig phosphacycles, respectively. A plausible mechanism is proposed on the basis of the control experiments and 31 P NMR spectra analysis. The absorption and emission properties of the obtained 1-phosphaphenalenes were also studied.

Density functional theory (DFT) calculations with 1-phenylselenylphosphirane complex 1 provide an insight into phosphirane fragmentation to phosphinidene complexes. FMO and ELF analyses show that the cleavage of two P-C σ bonds of phosphirane proceeds via an asynchronous concerted pathway. Transient [PhSeP-W(CO) 5 ] was generated by dissociation of 1 at 90 °C and trapped with different reagents. The 1-phenoxylphosphirane complex undergoes [1 + 2] retroaddition at a comparatively higher temperature which implies that the lone pair of the adjacent atom center of phosphorus plays a major role in phosphirane fragmentation.

Manipulating perovskite crystallization to prepare high-quality perovskite films is the key to achieving highly efficient and stable perovskite solar cells (PSCs). Here, a dynamic strategy is proposed to modulate perovskite crystallization using a resonance hole-transporting material (HTM) capable of fast self-adaptive tautomerization between multiple electronic states with neutral and charged resonance forms for mediating perovskite crystal growth and defect passivation in situ. This approach, based on resonance variation with self-adaptive molecular interactions between the HTM and the perovskite, produces high-quality perovskite films with smooth surface, oriented crystallization, and low charge recombination, leading to high-performance inverted PSCs with power conversion efficiencies approaching 22% for small-area devices (0.09 cm 2 ) and up to 19.5% for large-area devices (1.02 cm 2 ). Also, remarkably high stability of the PSCs is observed, retaining over 90%, 88%, or 83% of the initial efficiencies in air with relative humidity of 40-50%, under continuous one-sun illumination, or at 75 °C annealing for 1000 h without encapsulation., (© 2021 Wiley-VCH GmbH.)

Herein, we report a facile and highly atom-economic approach to 2-phosphafurans by using simple 2-chloroethylphosphine and acetylenic ketones. The key step of this protocol utilizes the Lewis acidity of electrophilic phosphinidenes to induce an intramolecular cyclization with enones. Dearomative hetero-Diels-Alder reactions of 2-phosphafurans provide two series of bicyclic phosphacycles. This rare synthetic application of Lewis acidity of electrophilic phosphinidene complexes represents a new frontier of phosphinidene chemistry.

Accurate and timely monitoring of streamflow and its variation is crucial for water resources management in watersheds. This study aimed at evaluating the performance of two process-driven conceptual rainfall-runoff models (HBV: Hydrologiska Byråns Vattenbalansavdelning, and NRECA: Non Recorded Catchment Areas) and seven hybrid models based on three artificial intelligence (AI) methods (adaptive neuro-fuzzy inference system (ANFIS), support vector machine (SVM), and group method of data handling (GMDH)) in simulating streamflow in four river basins in Indonesia. HBV and NRECA were developed based on precipitation data. Various combinations of 1-month lagged precipitation data together with outputs of HBV and NRECA were used for developing ANFIS and SVM models, and the best results of ANFIS and SVM formed the inputs to GMDH. Results showed that AI-based hybrid models have generally led to more accurate streamflow estimates compared with HBV and NRECA, and the GMDH model had the best performance at Cipero, Kedungdowo, Notog, and Sukowati stations, with RMSEs of 12.21, 6.07, 20.35, and 24.2 m 3 s -1 , respectively. More accurate estimation of peak values in training set at Cipero and Sukowati stations, and in both training and testing sets at Kedungdowo station was another advantage of GMDH. Hybrid models based on AI methods can be suitable alternatives to hydrological models, particularly in watersheds where there is a lack of measured data (e.g. climatic parameters, land cover-plant growth data, soil data, stream conditions, and properties of groundwater aquifers), provided that appropriate inputs are used., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The multiple-year drought that started in 2011 and reached climax in 2015 was the most severe and prolonged one in the semiarid northeastern (NE) Brazil in recent decades. This study aimed to investigate the reservoir surface water volume (SWV) variation in NE Brazil from 2009 to 2017 in four representative regions covering a total area of approximately 10,000 km 2 there and encompassing 2,140 reservoirs (areas range from 0.003 to 21 km 2 ). High-resolution (10 m) digital elevation models (DEMs) were generated from the TanDEM-X data acquired during October-December 2015 to represent the reservoirs' bathymetric maps. The water extents in the reservoirs were delineated from high-resolution (6.5 m) RapidEye images acquired during 2009-2017. The combination of the aforementioned two variables yielded reservoir SWV with an accuracy of 0.64 × 10 6 -1.06 × 10 6 m 3 , corresponding to 3.1%-5.6% of the maximum SWV in the reservoirs. The results showed that: 1) 81%-99% of the reservoirs in the four regions were from the groups with maximum water extent <50 ha and contributed 2%-59% of the regional reservoir SWV. In contrast, 0.6%-20% of the reservoirs were from the group of >50 ha and contributed 40%-98% to the regional SWV; 2) From 2009 to 2017, reservoir SWV in the four regions decreased at the rates of 2.3 × 10 6 -17.8 × 10 6 m 3 /year; and 3) The SWV in the reservoirs responded differently to the regional terrestrial water budget, i.e. the differences between precipitation and evapotranspiration (P-ET). This study filled the data gap of bathymetric maps for the 2140 reservoirs, regardless of their sizes and macrophyte coverage. The SWV variations derived in those reservoirs over a period covering the recent drought can support better preparedness for drought in NE Brazil and better understanding of the regional hydrology in semi-arid regions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Purpose: Total flavone of Abelmoschus manihot (TFA), the effective constituents extracted from Flos Abelmoschus Manihot , has been reported to inhibit inflammation. However, the effect of TFA on ulcerative colitis (UC) progression in patients with depression is unknown. The purpose of our research was to explore the anti-UC effects of TFA in the context of depression in mice with UC by regulating the gut microbiota to drive the intestinal barrier., Methods: In this study, chronic stress (CS) and dextran sodium sulfate (DSS) were used to induce depression and UC, respectively, in C57BL/6J mice. Fecal microbiota transplantation (FMT) was used to evaluate how treating mice modeling UC and depression with TFA effected their gut microbiota., Results: Our results showed that TFA effectively improved UC aggravated by CS. In addition, TFA treatment improved the depression-like phenotype, the disturbed gut microbiota, and the intestinal barrier function in CS mice. It is worth noting that FMT from the CS mice to the receptor group further aggravated the damage of the intestinal barrier and the disturbance of the gut microbiota in the recipient DSS mice, thus further aggravating UC, however, treatment of the intervention of TFA in the CS fecal microbiota transplant with TFA also played its therapeutic outcome., Conclusion: Taken together, our results show that CS disrupts the gut microbiota, triggers intestinal barrier injury and aggravates DSS colitis, while TFA is a promising drug for the treatment of UC in patients with depression., Competing Interests: The authors declare that they have no conflicts of interest., (© 2021 Wang et al.)

Remote Sensing, as a driver for water management decisions, needs further integration with monitoring water quality programs, especially in developing countries. Moreover, usage of remote sensing approaches has not been broadly applied in monitoring routines. Therefore, it is necessary to assess the efficacy of available sensors to complement the often limited field measurements from such programs and build models that support monitoring tasks. Here, we integrate field measurements (2013-2019) from the Mexican national water quality monitoring system (RNMCA) with data from Landsat-8 OLI, Sentinel-3 OLCI, and Sentinel-2 MSI to train an extreme learning machine (ELM), a support vector regression (SVR) and a linear regression (LR) for estimating Chlorophyll-a (Chl-a), Turbidity, Total Suspended Matter (TSM) and Secchi Disk Depth (SDD). Additionally, OLCI Level-2 Products for Chl-a and TSM are compared against the RNMCA data. We observed that OLCI Level-2 Products are poorly correlated with the RNMCA data and it is not feasible to rely only on them to support monitoring operations. However, OLCI atmospherically corrected data is useful to develop accurate models using an ELM, particularly for Turbidity (R 2 = 0.7). We conclude that remote sensing is useful to support monitoring systems tasks, and its progressive integration will improve the quality of water quality monitoring programs.

Two novel diastereoisomeric P-chirogenic phosphine catalysts, i.e., JiaPhos, which can be easily derived from inexpensive and commercially available starting materials in five chemical operations (totally 4.16g scale), are introduced. To our delight, the JiaPhos catalysts display good performance in enantioselective (4 + 2) annulations involving 3-methylene-2-oxindoles and γ-benzyl allenoates, providing a wide range of 3,3'-spirocyclic oxindoles with good efficiency and enantioselectivity.

We have developed an unprecedented approach for the synthesis of transient 1-phosphafulvenes through three component reactions of phospholes. The generation of 1-phosphafulvenes was demonstrated by in situ [6 + 4] cycloaddition with 2 H -phospholes and [6 + 6] self-dimerization. The [6 + 4] and [6 + 6] reaction pathway could be modulated by the starting ketones and aldehydes. The construction of 1-phosphafulvenes is illustrated by a proposed mechanism combining nucleophilic addition of phospholide to the iminium or isomerized azomethine ylide and a [1,5]-shift of phosphole.

Herein we reported a novel phosphine-catalyzed (4 + 2) cyclization reaction of electron-deficient conjugated dienes with enones to generate functionalized dihydropyran skeletons. A mechanistic investigation reveals that the reaction produces a new phosphonium zwitterion, which undergoes consecutive reactions. In addition, an asymmetric variant was developed by efficient and economical chiral phosphine catalysis.

Glacier retreat caused by global warming alters the hydrological regime and poses far-reaching challenges to water resources and nature conservation of the headwater of Yangtze River, and its vast downstream regions with dense population. However, there is still lack of a robust modeling framework of the "climate-glacier-streamflow" in this water tower region, to project the future changes of glacier mass balance, glacier geometry, and the consequent impacts on runoff. Moreover, it is imperative to use the state-of-the-art sixth phase Coupled Model Intercomparison Project (CMIP6) to assess glacio-hydrology variations in future. In this study, we coupled a glacio-hydrological model (FLEX G ) with a glacier retreat method (Δh-parameterization) to simulate glacio-hydrological processes in the Dongkemadi Glacier (over 5155 m.a.s.l), which has the longest continuous glacio-hydrology observation on the headwater of Yangtze River. The FLEX G -Δh model was forced with in-situ observed meteorological data, radar ice thickness, remote sensing topography and land cover data, and validated by measured runoff. The results showed that the model was capable to simulate hydrological processes in this glacierized basin, with Kling-Gupta efficiency (I KGE ) of daily runoff simulation 0.88 in calibration and 0.70 in validation. Then, forcing by the bias-corrected meteorological forcing from the eight latest CMIP6 Earth system models under two climate scenarios (RCP2.6 and RCP8.5), we assessed the impact of future climate change on glacier response and its hydrological effects. The results showed that, to the end of simulation in 2100, the volume of the Dongkemadi Glacier would continuously retreat. For the RCP2.6 and RCP8.5 scenarios, the glacier volume will decrease by 8.7 × 10 8  m 3 (74%) and 10.8 × 10 8  m 3 (92%) respectively in 2100. The glacier runoff will increase and reach to peak water around 2060 to 2085, after this tipping point water resources will likely decrease., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Secondary fracture healing is a complex multi-stage process in which the mechanical environment plays a key role. The use of an appropriate mechanical stimulation such as strain is conducive to tissue formation between fracture ends, thus aiding the healing process. However, if the strain is too large or too small, the biological behavior of the cells involved in bone healing will be affected, resulting in non-union or delayed healing. In this review, we summarize the current state of knowledge regarding the effect of strain on cells that play a role in the fracture-healing process. Overall, the related literature suggests that selection of an adequate strain promotes fracture healing through the stimulation of angiogenesis and osteogenesis, along with inhibition of osteoclast differentiation and bone resorption. However, standardized methods for the application of mechanical stimulation are lacking, and a unified consensus on the mechanism by which strain promotes cell differentiation has not yet been reached. These issues, therefore, deserve further investigation., (© 2021 The Authors. Orthopaedic Surgery published by Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.)

The coordination chemistry of 1-phosphafulvenes was investigated by employing their [6 + 4] adducts or α-C 2 -bridged biphospholes as a precursor. Unbridged phosphacymantrenes arise from 1-phosphafulvenes via proton abstraction. α-C 2 -bridged biphosphacymantrenes are probably yielded by the reductive coupling of 1-phosphafulvene with Mn 2 (CO) 10 . The coordination behavior of 1-phosphafulvenes is comparable to that of pentafulvenes, which again demonstrates the phosphorus-carbon analogy in low-coordinate organophosphorus chemistry.

Micro-plastics (MPs) pollution has been a hotspot in soil environment. To explore the correlation of the vegetation cover and the distribution of MPs in Yellow River Delta wetland, the characters of MPs in the soil sampled at 16 sites where reed ( Phragmites communis , a low-salt dominant species) and Suaeda salsa (a high-salt dominant species) covered were investigated. The abundance of MPs here ranged to 80-4640 n·kg -1 , and the particle size ranged to 13 μm-5 mm. The main components of MPs with large size were polyethylene (PE), polyethylene terephthalate (PET) and polystyrene (PS), and the content of PET ranged to 0.22-1.16 μg·kg -1 . The barrier effect of reed on MPs was higher than that of Suaeda salsa . The average abundance of MPs and PET contents at the sites where reed covered were 1423 n·kg -1 and 0.62 μg·kg -1 , and they mainly consisted of small particles with a size less than 50 μm. The average abundance of MPs and PET contents at the site Suaeda salsa covered were 584 n·kg -1 and 0.33 μg·kg -1 , and they mainly consisted of fragments and fibers with a size ranged to 100-1000 μm. The abundance of MPs in the soil was significantly correlated with the growth statues of the vegetations ( P =0.001). Therefore, the distribution of MPs in the soil in the same area covered by different vegetation might be spatial different.

[1 + 2] cycloaddition is a classical reaction between the electrophilic phosphinidene and an alkene. However, a spatial constraint blocks this well-known reaction and enables an unprecedented chemoselective C(sp 2 )-Ar σ-bond insertion of the alkene. The theoretical calculations demonstrate that this C-C bond cleavage is energetically feasible and thermodynamically favored through an electrophilic rearrangement and concomitant 1,9-aryl migration without involving any strained intermediate.

We use a 785 nm shifted excitation Raman difference (SERDS) technique to measure the Raman spectra of the conidia of 10 mold species of especial toxicological, medical, and industrial importance, including Stachybotrys chartarum, Penicillium chrysogenum, Aspergillus fumigatus, Aspergillus flavus, Aspergillus oryzae, Aspergillus niger, and others. We find that both the pure Raman and fluorescence signals support the hypothesis that for an excitation wavelength of 785 nm the Raman signal originates from the melanin pigments bound within the cell wall of the conidium. In addition, the major features of the pure Raman spectra group into profiles that we hypothesize may be due to differences in the complex melanin biosynthesis pathways. We then combine the Raman spectral data with neural network models to predict species classification with an accuracy above 99%. Finally, the Raman spectral data of all species investigated is made freely available for download and use., Competing Interests: The authors have declared that no competing interests exist.

A simple method to build phospholene derivatives has been achieved in a one-pot reaction with readily available o -alkynylaryl bromides and alkylphosphine oxides. This method is also applicable to synthesize P-stereogenic phospholenes, and the resulting chiral phosphine was utilized as a ligand for coordination chemistry.

An unusual chemoselective 1,1-addition of α-C 2 -bridged biphospholes to terminal alkynes is reported. The developed protocol provides simple access to the unknown 1,3-diphosphepines, which has potential applications in the coordination and catalyst chemistry. Their Pd and Mo complexes were studied by single-crystal X-ray diffraction analysis. This method features excellent chemoselectivity, high step and atom economy, mild reaction conditions, and wide substrate scope.

Thermolysis of the 1,1'-biphosphirane pentacarbonylmetal complex offers access to 3,4-dihydro-1,2-diphosphete and diphosphorus (P2) intermediates. A control reaction proves that this step-wise reaction is initiated by the dissociation of a W(CO)5 group. DFT calculations predict that further transformations proceed via a transient phosphiranylphosphinidene complex. The formation of the 3,4-dihydro-1,2-diphosphete derivative is thermodynamically favored, while a kinetic process provides the diphosphorus (P2) complex.

Mercury is, because of its high vapor pressure and its prevalence in the atmosphere as atoms, an interesting geophysical tracer gas, also with potential archaeological applications. According to historical records dating back 2200 years, the mausoleum chamber of the "Terracotta Army Emperor" Qin in Xi´an, China, contains large amounts of liquid mercury, considered as an elixir of life at the time. We here report on measurements of the atmospheric contents of atomic mercury above the tomb mound performed with a mobile differential absorption lidar (light detection and ranging) system. Our measurements, which were performed from three different locations around the mound, indeed indicate elevated atmospheric mercury levels, with localizations, which correlate with previous in situ soil sampling results. Concentrations up to 27 ng/m 3 were observed, significantly higher than the typical general pollutant level in the area which was found to be around 5-10 ng/m 3 . An out-flux of about 5×10 -8  kg/s was estimated. Highly volatile mercury may be escaping through cracks, which developed in the structure over time, and our investigation supports ancient chronicle records on the tomb, which is believed never to have been opened/looted. Our findings also have bearings on the proposed use of mercury as a tracer gas for valuable ores and geothermal resource exploration, and also bring problematics around reliable nuclear waste long-term underground storage to mind.

A copper-catalyzed asymmetric 1,3-dipolar cycloaddition of glycine iminoesters with alkyl substituted 3-methylene-2-oxindoles is described. By using de novo design of P-stereogenic phosphines as ligands, spiro[pyrrolidin-3,3'-oxindole]s are generated in good to excellent yields with high asymmetric induction. A further reduced catalyst loading of 0.1 mol% is sufficient to achieve a satisfactory enantioselectivity of 90% ee. The DFT calculations suggest the second Michael addition of the 1,3-dipole to be the rate- and enantio-determining step. A key feature of this 1,3-dipolar cycloaddition is the wide substrate applicability, even with alkyl aldehyde-derived azomethine ylide; thus it has streamlined a highly enantioselective access to a new class of antiproliferative agents, MDM2-p53.