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By the end of 2020, 45 cities in the Chinese mainland operated 244 urban rail transit lines with a total length of 7,969.7 km, Urban rail transit in Chinese cities witnessed a steady growth both in operating scale and passenger traffic in 10 years. Recent studies have explored the environmental and social effects of urban rail transit; however lack in-depth discussion on economic growth. As a quasi-natural experiment, this paper empirically tests the effect of the opening of urban rail transit on urban economic growth based on the panel data of 286 prefecture-level cities in China from 2008 to 2020 and PSM-DID Model. Analysis results show that, rail transit drives urban economic growth. This effect has scale heterogeneity and regional heterogeneity. The findings of this study can provide a valuable reference for the government when it plans the layout of urban rail transit for construction.

Gas concentrations of different sections in return airway of working face were tested, and the gas distribution contours of roadway section were made for studying gas concentration distribution. Conclusions: gas distribution in different sections of roadway is uneven, and gas will be fully homogeneous with air after moving 100 m in front of working face; goaf gas pouring out through the upper corner has a greater impact on distribution of gas concentration. Recommendations for layout of gas monitoring points and sensors in return air of working face were provided, namely gas sensors in return airway should be arranged in central line of the roadway less than 300 mm away from the roof, and a sensor measuring point should be arranged at the place 10 m away from the upper corner.

Four prenylated indole alkaloids (1−4) were targeted isolated from the mangrove rhizosphere soil-derived fungus Penicillium janthinellum HK1-6 by using molecular networking strategies. Among them, the planar structure and relative configuration of notoamide X (1) were elucidated by detailed analysis of the spectroscopic data especially the NOESY spectrum for the first time and its absolute configuration was determined by ECD spectrum. Furthermore, curated molecular networks of MS/MS data were generated with GNPS which allowed highlighting six prenylated indole alkaloids (5, 6, 8, 9, 11, 12) that had not previously been identified in this fungus and two (7, 10) that had never been observed in any fungus. The MS/MS fragmentation pathway of these prenylated indole alkaloids was summarized. [ABSTRACT FROM AUTHOR]

The search was conducted by a combination of subject terms and free words, and the Chinese search terms included: Chinese medicine, cancer-caused fatigue, cancer fatigue, cancer, tumor, fatigue, fatigue, randomized, and control. Clinical study on Fuzheng Sanjie Jiedu recipe in the treatment of cancer-related fatigue in patients with colorectal cancer after postoperative chemotherapy. Cancer-caused fatigue originates from cancer itself, and different cancer types invade different internal organs, and different patients have a different physical constitution, so a clear standard TCM symptom score is of vital importance. On the other hand, cancer fatigue is different from ordinary illnesses, and any treatment has a big impact on the progression of cancer and the patient's condition. [Extracted from the article]

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The evaluation of rock mechanic characteristics of shale reservoir is the key for the success of fracturing. Several limitations such as complex lithology can affect the accuracy of the rock mechanic property computation. In this research, the mechanical rock properties of shale reservoirs were analyzed based on experimental tests including shale-reservoir mineral composition, uniaxial compressive strength, and triaxial compression tests. The results showed that (1) the difference in mineral composition leads to easier fracturing of sand shale reservoirs compared with pure shale reservoir. (2) Under uniaxial conditions, the rock mechanical parameters along the vertical bedding direction of sand shale reservoirs are better than pure shale reservoir parameters. The mechanical properties of shale reservoirs in parallel bedding direction are less affected by lithology. Under triaxial conditions, the confining pressure increases more than 4.0 times with the compressive strength of rocks, and the rock Young's modulus in the parallel bedding direction is higher compared with the vertical bedding direction. (3) Rock failure mode is mainly subdivided into cutting and splitting modes, and the bedding features of rock mechanic properties highly influence the drilling and fracturing operations. This study offers guidelines for the optimization of the drilling and fracturing process based on accurate evaluation of the rock mechanical properties. [ABSTRACT FROM AUTHOR]

Concise one-pot biarylamination of quinones with arylamines was developed to synthesize N -arylamine-functionalized p -iminoquinones derivatives. The approach employed AgOAc as the catalyst and (NH4)2 S2 O8 as the oxidant in the presence of 3-chlorophenylboronic acid, giving a series of N -arylamine-functionalized p -iminoquinone derivatives in moderate to good yields whereas reaction in the absence of the 3-chlorophenylboronic acid, gave a series of N -arylamine-functionalized 1,4-naphthoquinone derivatives. This catalytic approach represents a step-economic and convenient strategy for the difunctionalization of quinones. [ABSTRACT FROM AUTHOR]

Seven new copper(ii) coordination networks combining flexible 3,3′,5,5′-tetramethyl-4,4′-bipyrazole (bpz) and diverse dicarboxylates, [Cu(bpz)0.5(adip)]n (1), [Cu2(bpz)4(sub)2]n (2), [Cu4(bpz)1.5(aze)·H2O]n (3), [Cu2(bpz)(pta)2(H2O)·H2O]n (4), [Cu2(bpz)(ipa)]n (5), [Cu2(bpz)(o-pda)2·H2O]n (6), and [Cu2(μ3-OH)(bpz)(p-pda)1.5·H2O]n (7) (H2adip = adipic acid, H2sub = suberic acid, H2aze = azelaic acid, H2pta = phthalic acid, H2ipa = isophthalic acid, H2o-pda = o-phenylenediacetic acid, H2p-pda = p-phenylenediacetic acid), have been obtained under solvothermal conditions and structurally verified by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, powder X-ray diffraction (PXRD), infrared spectroscopy (IR), UV-vis spectroscopy and thermogravimetric analyses (TGA). Single crystal X-ray diffraction analysis revealed that both 1 and 6 are 6-connected pcu networks (point symbol: {412·63}) based on paddle-wheel [Cu2(COO)4] secondary building units (SBU). Complexes 2 and 4 are 2D 44-sql networks based on a single metal ion node and a binuclear [Cu2(COO)4(H2O)] SBU, respectively, while complex 3 features an extremely rare 3D 5-connected hxg-d-5-C2/c (point symbol: {42·67·8}) network. Complex 5 shows a 1D tape structure built from bpz sealed 1D helical Cu2(ipa) chains along the b axis, and 7 is a 3D 8-connected hex (point symbol: {36·418·53·6}) network based on a centrosymmetric [Cu4(μ3-OH)2(COO)4] SBU. A thorough structural comparison of these coordination networks suggests that the coordination fashions, conformations of dicarboxylates along with the different inorganic Cu(ii) SBUs simultaneously play a significant role in constructing the diverse networks. Variable-temperature magnetic susceptibility data denote that 4 and 7 display antiferromagnetic interactions in binuclear [Cu2(COO)4(H2O)] and [Cu4(μ3-OH)2(COO)4] SBUs. Moreover, the thermal stability and UV-vis spectra of 1–7 are discussed in detail. [ABSTRACT FROM AUTHOR]

According to the requirements in real-time, accuracy and convenience characteristics of pre-warning technology in coal and gas outburst, the characteristics and regularity of electromagnetic radiation in coal and rock fracture, and regularity and relativity of electromagnetic radiation and conventional indexes during coal and gas outburst evolution were analyzed. The coal and gas outburst electromagnetic radiation warning equipment and software were developed. The pre-warning criteria of coal and gas outburst forecasting with electromagnetic radiation was built. The automatic analysis and pre-warning of electromagnetic radiation in coal and gas outburst forecasting was realized. The results showed that there was high positive correlation between electromagnetic radiation and conventional indexes of coal and gas outburst, which could reflect coal and gas outburst risk. The field application of coal and gas outburst pre-warning results showed that electromagnetic radiation had high pre-warning accuracy, and could predict outburst hazard ahead 13 meters or ahead two days. [ABSTRACT FROM AUTHOR]

Cocrystallizationof a versatile organic tecton, 3,3′,5,5′-tetramethyl-4,4′-bipyrazole(tmbpz), with aliphatic dicarboxylic acid suberic acid (H2sub) and sebacic acid (H2seb) generates two supramolecularsolids [(tmbpz)2·(H2sub)] (1) and [(tmbpz)2·(H2seb)] (2). In the present case, both cocrystals could be obtained from eithersolution evaporation or mechanochemical solid-state reaction. Single-crystalstructural analyses reveal that the 1and 2are 4-fold and 5-fold 2D → 2D parallel interpenetrated 63-hcb networks, respectively. The substantial dissimilaritiesin the degree of interpenetration are modulated by the different lengthsof dicarboxylic acids. The thermal stabilities and photoluminescencebehaviors of them were also discussed. [ABSTRACT FROM AUTHOR]

In order to study the surface electric potential signals during the coal adsorbing gas, designed the experiment system of the coal adsorbing gas and tested the electric potential signal generated during the coal adsorbing gas under different gas pressure. Experiment results show that surface potential signals can be generated in the process of adsorbing gas, and they increases gradually along with the growth of adsorption time. For the same coal samples, different gas pressure from the coal surface potential signal to the first adsorption gas pressure of coal potential signal has a memory effect in the process of absorption. When the adsorption gas pressure is higher than the first adsorption gas pressure, the coal induces stronger surface potential signals. And when the adsorption gas pressure is lower than the first adsorption gas pressure, the coal induce weaker surface potential signals. The main reasons why surface potential signals can be generated from coal adsorbing gas are that the gas seepage in coal pores produces flow potential and free charge is generated when the gas damages micro cracks and crack of coal. [ABSTRACT FROM AUTHOR]

An investigation was conducted on the characteristics of surface current induced by coal under uniaxial compression. An interpretation of the mechanisms governing the electrical behavior of the coal structures under uniaxial stress tests was presented in this paper. The experimental results show that the current signal is generated during the deformation and fracture process of coal samples. When the load is applied, the electric current makes its initial appearance and increases rapidly after a considerable time lag at 8C, until after the stress reaches a value δc ≈0.75δmax where δmax is the maximum applied stress before sample fracture. There is a good correlativity between the current and the load, and the correlation coefficient between them can reach up to 0.8 to 0.9. The current peaks occur under sudden loading and unloading. It suggests that the current is closely related to the loading. The status of coal loading level may be determined by the current signal. The intensive study on coal surface current can provide a way for monitoring the stability of coal and rock. [ABSTRACT FROM AUTHOR]

The experiment was made on the rules of surface potential of coal or rock during friction process. The mechanism producing surface potential of coal or rock friction was discussed initially. The results show that surface potential can be produced during coal or rock friction process, and it has a better corresponding relationship with load. The coal or rock friction process can be divided into two stages: static friction stage and kinetic friction stage. The surface potential signal in kinetic friction stage was stronger than that in static friction stage. During rock friction process, the polarity of surface potential signal was basically bidirectional mutation, and the polarity of surface potential on both sides of friction surface had obvious symmetry. While the polarity of surface potential signal was basically unidirectional mutation in coal friction process, and the polarity of surface potential on both sides of friction surface was not in significant symmetry. The changes of surface potential during coal or rock friction process can be explained by mechanism of electricity produced by friction, thermionic emission and field electron emission. [ABSTRACT FROM AUTHOR]

In order to study the relationship between surface potential distribution and destruction localization of the coal sample, the distribution law of strain field and surface potential of coal samples were tested under load. The relationship between surface potential field and strain localization & fracture of coal samples was studied and analyzed. Results show that the coal samples show obvious strain localization characteristics in deformation and failure process, the strain localization concentrated area is the severe damage and fracture part of coal samples, and the strain localization zones is usually the fracture location of coal samples. The distribution character of surface potential field of coal samples during deformation and fracture is similar to the strain field, the potential field will be centralized in the damage localization area, the connection between the points of high potential and low potential reflects the rupture section of coal samples. [ABSTRACT FROM AUTHOR]

The controllable key factors in magnetorheological finishing device were studied to determine their influence on efficiency of magnetorheological finishing ( MRF ) and surface of MRF, as well as interaction between efficiency and surface. Based on theoretical and experimental research, the law of material removal was explored and a new process variable based material removal model (PVMR) was proposed. The experimental findings demonstrate that PVMR reveals the law of the material removal with introduction of three concepts and makes a material removal function z (y i) where the magnetorheological finishing process parameters are considered since they are easy to control and adjust. So the material function of this model is quadratic curve function which is readily suitable for stability and online control magnetorheological finishing. [ABSTRACT FROM AUTHOR]

Abstract: A novel series of two-dimensional π-conjugated oligoarylenes has been synthesized by a divergent approach using Pd-catalysed Suzuki cross-coupling of tetraiodophenylbenzene and arylboronic acid as a key step. It has been shown that the ‘X-branched’ structure can provide a useful platform to construct amorphous molecular materials as it can enhance the morphological and thermal stability as well as to facilitate solubility and processibility of a material when compared to those of the corresponding linear oligomers. The diphenylamino end-capped two-dimensional oligoarylenes were found useful as a hole transporting/emitting layer for light emitting applications. [Copyright &y& Elsevier]

This letter reports high performance AlGaN solar-blind avalanche photodiodes (APDs) with separate absorption and multiplication structure grown by metal–organic chemical vapor deposition on AlN templates. In fabricating APD devices, we applied a photo-electrochemical treatment process after mesa etching to reduce damage induced by etching. After introducing this process, the leakage current of the fabricated devices was reduced obviously and a record-high gain of 1.2\times 10^4 at the reverse bias of 84 V was achieved under the measurement condition with the protection current constrained to 10^-5~A. [ABSTRACT FROM AUTHOR]

The non-coplanar substituted phenyl rings at the 9-position of a fluorenyl unit can be involved in π-electron delocalization in which the resulting oligofluorenes exhibit a very large enhancement of two-photon absorption cross sections up to 2559 GM at 710 nm. [ABSTRACT FROM AUTHOR]

GaN films with an AlxGa1−xN/AlyGa1−yN superlattice (SL) buffer layer are grown on Si(111) substrates by metal-organic chemical vapor deposition (MOCVD). The structure and strain properties of the samples are studied by optical microscopy, Raman spectroscopy, x-ray diffractometry and atomic force microscopy. The results show that the strain status and crystalline quality of the GaN layers are strongly dependent on the difference of the Al composition between AlxGa1−xN barriers and AlyGa1−yN wells in the SLs. With a large Al composition difference, the GaN film tends to generate cracks on the surface due to the severe relaxation of the SLs. Otherwise, when using a small Al composition difference, the crystalline quality of the GaN layer degrades due to the poor function of the SLs in filtering dislocations. Under an optimized condition that the Al composition difference equals 0.1, the crack-free and compressive strained GaN film with an improved crystalline quality is achieved. Therefore, the AlxGa1−xN/AlyGa1−yN SL buffer layer is a promising buffer structure for growing thick GaN films on Si substrates without crack generation. [ABSTRACT FROM AUTHOR]

In order to analyze the failure mechanism of coal under the load, multi-fractal characteristics of surface potential of coal sample under uniaxial compression was studied. The surface potential was analyzed using multi-fractal theory to calculate the multi-fractal spectrum. The change rules of characteristic parameters of multi-fractal spectrum with the loading process were studied. The results show that the surface potential represents multi-fractal feature, and keeps scale invariance in the wide range. The shape of the multi-fractal spectrum of different size specimens shows right hook. The characteristic parameters of multi-fractal spectrum, Δα and Δf, vary with the process of deformation and fracture of coal sample with load. The changes of trend that Δα and Δf increase in a long time, then decrease rapidly can be used as a precursory factor of coal-rock failure to forecast the instability of the samples. The results are helpful to understand the inherent law in the coal specimen failure process and forecast the dynamic disaster using the potential. [ABSTRACT FROM AUTHOR]

Acoustic emission signals generated in process of methane sorption and seepage in coal were observed, and the dynamic characteristic of damage evolution and the seepage process were analyzed based on the characteristic of acoustic emission. The experiments indicated that the strength of acoustic emission decreased with the adsorbed methane increase. And the acoustic emission showed paroxysmal in time domain. The results give implication that the methane seepage in coal layer by layer. In its seepage process, methane shows destructive seepage while the gas pressure gradient was bigger than the threshold value. Then, pressure of the seepage face decreased and the methane shows undestructive seepage. Sorption process tends to equilibrium with the gas pressure increase. [ABSTRACT FROM AUTHOR]

A homologous series of 9,9-diphenyl substituted oligofluorenes end-capped by diphenylamino groups, (Ph) -OF( n )-NPhs, n = 1–5, has been synthesized using Suzuki cross coupling reaction as a key step and were fully characterized by 1 H NMR, 13 C NMR, MS, and elemental analyses. The functional properties, including thermal stabilities, linear optical properties, fluorescence and electro-chemical properties, were investigated. The TPA cross sections of these newly synthesized oligofluorenes were measured by the TPF method. Compounds (Ph) -OF(4)-NPh and (Ph) -OF(5)-NPh exhibited larger two-photon absorption cross-sections, about 550 GM and 1390 GM at 800 nm, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Four monodisperse symmetric bis-dendronized arylenes, DPh-EG, Ph-EG, FPh-EG and DTh-EG have been successfully synthesized by a convergent approach using copper-catalyzed Buchwald''s amination as a key step and characterized by a combination of 1H NMR, 13C NMR, MS, and HRMS. All these bis-dendronized arylenes exhibit high thermal stabilities, good amorphous morphological stabilities and high energy-transfer efficiencies (76%, 73%, 78% and 68%, respectively for DPh-EG, DTh-EG, FPh-EG and Ph-EG). [Copyright &y& Elsevier]

Abstract: A facile approach for synthesis of the triarylamine-endcapped X-branched oligofluorene, X-OF(2)Ph-NPh and its corresponding linear oligofluorene, OF(2)Ph-NPh by Suzuki cross-coupling as a key reaction has been developed. This novel X-branched oligofluorene exhibits much higher thermal and electrochemical stabilities and enhanced electroluminescent properties as comparison to its corresponding linear counterpart. Using a simple two-layer OLED structure of ITO/oligofluorene (40nm)/PBD (40nm)/LiF (1nm)/Al (150nm), the luminance efficiency of X-OF(2)Ph-NPh-based OLED can also reach up to 2.8cd/A with a maximum brightness of 1700cd/m2 and remarkably better than 1.2cd/A with a maximum brightness of 700cd/m2 for its corresponding linear oligofluorene OF(2)Ph-NPh-based OLEDs. [Copyright &y& Elsevier]

Abstract: 2,7- and 3,6-Bis [7-diphenylamino-9,9-di(n-butyl) fluorene-2-yl]dibenzo-thiophene S,S′-dioxides, 2,7-OF(2)BTO-NPh and 3,6-OF(2)BTO-NPh have been synthesized by a convergent approach using palladium-catalyzed Suzuki cross-coupling or copper-catalyzed Buchwald''s amination as the key reactions. The functional properties including thermal stabilities, optical properties, electrochemical properties of these two oligomers, as well as the performance of 2,7-OF(2)BTO-NPh-based OLEDs have been investigated and discussed. With a simple three-layer structure of ITO/3,6-OF(2)BTO-NPh (40nm)/F-TBB (15nm)/Alq3 (20nm)/LiF (1nm)/Al (75nm), the luminance efficiency of 3,6-OF(2)BTO-NPh-based OLEDs can also reach up to 0.42cd/A with a maximum brightness of 1620cd/m2. [Copyright &y& Elsevier]

'On Water'-promoted the three-component tandem Michael addition/D-A cycloaddition reaction in 80 °C at 3 h has been developed without employing any catalyst and organic solvent. The process allows facile access to polycyclic N-heterocycles derivatives contain indole and maleimide from easily accessible starting materials in moderate to high yields (up to 91 %). Compared with conventional reaction conditions, this reaction not only improves the reaction efficiency and rate but also minimizes the side reaction., (© 2023 Wiley-VHCA AG, Zurich, Switzerland.)

Background: The therapeutic effects of a combination of Chinese medicines called Baihedihuang decoction (BD) have been clinically verified, although its molecular targets in breast cancer related anxiety remain unknown., Aim: To explore the molecular mechanisms of BD for breast cancer related anxiety treatment., Methods: We used the Traditional Chinese Medicine Systems Pharmacology database to screen the active ingredients and potential targets of BD, and constructed the "drug-ingredient-target" network map with the help of Cytoscape 3.8 software. Also, we used the Online Mendelian Inheritance in Man, DrugBank, and Gencards databases to collect the disease targets of breast cancer related anxiety, and used the STRING platform to perform protein interaction analysis and construct the protein-protein interaction network. Metascape platform was used for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of key targets. Molecular docking technology was used to verify the drug component/target disease network., Results: We screened 16 active ingredients of BD for breast cancer related anxiety, with 113 target proteins. There are 931 disease targets of breast cancer related anxiety, and finally, 43 key targets and 305 Kyoto Encyclopedia of Genes and Genomes pathways were generated. The main active ingredients of BD for breast cancer related anxiety are verbascoside, β-sitosterol, stigmasterol, catalpol, etc. CDK2, TP53, HTR2A, ESR1, etc. are its key targets, and the main involved signaling pathways may include neuroactive ligand-receptor interaction pathway, 5-hydroxytryptaminergic synapse, P53 signaling pathway, cGMP-PKG signaling pathway, the cAMP signaling pathway, etc. Finally, molecular docking was performed with Vina software to validate the key active ingredients in BD with the selected key action targets. The molecular docking results showed that verbascoside, β-sitosterol, stigmasterol and CDK2 could stably bind and interact through amino acid residues SER249, ARG260, PRO228, ALA282, SER276, LYS273, ASN272, etc., Conclusion: The therapeutic effect of BD for breast cancer related anxiety is multi-level, multi-target, and multi-pathway. The findings of this study provide ideas and basis for further research., Competing Interests: Conflict-of-interest statement: All authors declare that there is no conflict of interest regarding the publication of this paper., (©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.)

Understanding the genetic mechanisms of phenotypic variation in hybrids between domestic animals and their wild relatives may aid germplasm innovation. Here, we report the high-quality genome assemblies of a male Pamir argali ( O ammon polii , 2 n = 56), a female Tibetan sheep ( O aries , 2 n = 54), and a male hybrid of Pamir argali and domestic sheep, and the high-throughput sequencing of 425 ovine animals, including the hybrids of argali and domestic sheep. We detected genomic synteny between Chromosome 2 of sheep and two acrocentric chromosomes of argali. We revealed consistent satellite repeats around the chromosome breakpoints, which could have resulted in chromosome fusion. We observed many more hybrids with karyotype 2 n = 54 than with 2 n = 55, which could be explained by the selfish centromeres, the possible decreased rate of normal/balanced sperm, and the increased incidence of early pregnancy loss in the aneuploid ewes or rams. We identified genes and variants associated with important morphological and production traits (e.g., body weight, cannon circumference, hip height, and tail length) that show significant variations. We revealed a strong selective signature at the mutation (c.334C > A, p.G112W) in TBXT and confirmed its association with tail length among sheep populations of wide geographic and genetic origins. We produced an intercross population of 110 F 2 offspring with varied number of vertebrae and validated the causal mutation by whole-genome association analysis. We verified its function using CRISPR-Cas9 genome editing. Our results provide insights into chromosomal speciation and phenotypic evolution and a foundation of genetic variants for the breeding of sheep and other animals., (© 2022 Li et al.; Published by Cold Spring Harbor Laboratory Press.)

Background: Gemcitabine plus nab-paclitaxel (GA) is a commonly used first-line treatment regimen for metastatic pancreatic cancer, and many studies will add a novel targeted agent to this regimen for improving patient survival rate. However, the clinical effectiveness of GA is the most controversial issue., Aim: To compare the efficacy and safety of GA regimen with a targeted agent and GA regimen., Methods: Up to 1 December 2021, the eligible randomized controlled trials (RCTs) relating to GA and GA with a targeted agent were searched on PubMed, EMBASE and Cochrane Library for eligible data. We screened out appropriate studies for overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and toxicity, which had been pooled and finally analyzed by using Stata version 15.1. In addition, we use Reference Citation Analysis (https://www.referencecitationanalysis.com/) to collect the latest related literature to improve the latest cutting-edge research results., Results: Seven RCTs involving 1544 patients (848 men and 696 women) were included. There were no significant differences between GA with a targeted agent and GA in PFS [hazard ratio (HR): 1.18 95% confidence interval (CI): 0.91-1.53], OS (HR: 1.12 95%CI: 0.99-1.27), and ORR (HR: 0.96 95%CI: 0.71-1.29). There was no notable difference in the two groups in grade 3/4 toxicity (fatigue, anemia, vomiting and neutropenia), whereas the incidence of grade 3/4 diarrhea considerably increased in GA with a targeted drug., Conclusion: Adding a novel targeted agent to the GA regimen did not improve survival rate of patients with metastatic pancreatic cancer., Competing Interests: Conflict-of-interest statement: The authors declare that there is no potential conflict of interest., (©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.)

An efficient metal-free, (NH 4 ) 2 S 2 O 8 mediated oxidative dearomatization of indoles for the construction of C2-quaternary indolinones was disclosed. A series of C2-quaternary indolinones derivatives with good functional group tolerance were obtained in moderate to excellent yields. This methodology provides an alternative approach for the direct generation of all-carbon quaternary centers at the C2 position of indoles. This catalytic approach represents a step-economic and convenient strategy for the oxidative dearomatization of indoles., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

To find out the recessive factors of soil degradation threatening the healthy development of Weibei apple orchards, we examined soil compaction status and its inducing factors. This study could provide a theoretical basis for apple orchard scientific management. We evalua-ted the changes of soil bulk density and compaction with the depth of soil layer in 0-60 cm in four apple orchards with various planting period, including <10 years (4-6 years), 10-20 years (14-16 years) and ＞20 years (24-26 years). The location and degradation degree of soil compaction in orchard were investigated. Through analyzing the number of soil aggregates and the stability, soil clay and organic matter contents, we tried to find the reasons for the internal compacting of soil in Weibei orchards. The results showed that soil bulk density and compactness in the 0-60 cm soil layer significantly increased with increasing planting years and soil depth. With the 20 cm soil layer as a boundary, soil of Weibei orchards in different planting years showed obvious variation characteristics of loose in upper and compact in lower. The above indicators in soil layer above 20 cm basically met the normal requirements of apple trees, whereas soil layer below 20 cm exceeded the threshold for healthy growth of apple trees. The main reasons for soil compaction below the subsurface layer were poor soil aggregation, the lack of soil organic matter, less human disturbance during fruit planting, and the movement of scattered clay particles to the lower layer. With increasing years of fruit planting, soil compaction became more severe.

Application of biochar (BC) is an important way to increase soil organic carbon sequestration. At the same time, the effect of BC on fractions and properties of soil humic substances is concerned. A laboratory experiment was conducted to study the influences of BC pyrolyzed at different temperatures on the composition and properties of humic substances. The modified method for the extraction and fractionation of humic substances was adopted in this work. The carbon (C) contents of Humin (Hu), Humic acids (HA), Fulvic acids (FA) were analyzed by the thermal oxidation of K 2 Cr 2 O 7 and TOC analyzer, and the optical properties of HA and FA were measured by using spectrophotometer. The results showed that the increasing temperature (from 300 to 600℃) decreased like-humic substances (LHS) from 10.93 g·kg -1 to 0.26 g·kg -1 , while the structure of theLHS tended to be complicated. Compared with control treatment (CK), the addition of BC produced under 400℃ increased the contents of HA and FA (after 240 d incubation a lower FA content was found in treatments) and increased as BC application rate increased, after 360 d of incubation, BC300 and BC400 significantly increased by 69.93% and 48.75% for HA ( P <0.05), while decreased by 1.35% and 5.19% for FA. Higher contents of HA and FA were found in soil samples amended with BC prepared at above 400℃ only during the initial period of 3-10 d of incubation and increased as BC application rate increased, at the end of the incubation, the contents of HA and FA significantly decreased by 34.38%, 44.48% in BC500 treatments and 42.84%, 49.27% in the BC600 treatments ( P <0.05). During the incubation, the addition of BC significantly increased the contents of Hu ( P <0.05), and the treatments amended with BC500 were the highest. The addition of BC decreased the relative contents of HA and FA, while increased the relative content of Hu, indicating that the proportion of relatively stable organic carbon in the soil was increased. The ratio of HA/FA (H/F) varied between 0.88 and 2.52 and increased with decreasing pyrolysis temperature and increasing BC application. A significantly lower color tonal coefficient (Δlg K ) and E 4 / E 6 values in treatments amended with BC produced at temperatures above 400℃, indicating that higher temperatures derived BC complicated the structure of soil humic substance, while an opposite rend was observed in treatments amended with BC produced at temperatures under 400℃. Considering the improvement of the stability of organic carbon, when the BC products were applied to the Loutu soil, 500℃ was the optimal temperature for preparing apple-derived BC not only because it could significantly increase the content of inert soil organic carbon, but also improve the quality of the soil as a result of enhancing the degree of soil humification.