Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines:Mechanism,scope,and application

Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective.In this respect,catalytic deoxygenative amide reduction has proven to be promising but challenging,as this approach necessitates selective C-O bond cleavage.Herein,we report the selective hydroboration of primary,secondary,and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst,Zr-H,for accessing diverse amines.Various readily reducible functional groups,such as esters,alkynes,and alkenes,were well tolerated.Furthermore,the methodology was extended to the synthesis of bio-and drug-derived amines.Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C-N bond cleavage-reformation process,followed by C-O bond cleavage.

High-mobility group box 1 expression and lymph node metastasis in intrahepatic cholangiocarcinoma

AIM:To evaluate the prognostic value of high-mobility group box 1(HMGB1) expression in intrahepatic cholangiocarcinoma(IHCC) and the possible underlying mechanism.METHODS:Tissue microarray was constructed from 65 IHCC patients.Immunohistochemistry was performed to validate expression of HMGB1 and Vascular endothelial growth factor C(VEGF-C).Realtime PCR and Western blot analyses were used to study transcript and protein levels.The interaction between HMGB1 and VEGF-C was evaluated by si RNA,real-time PCR,and enzyme-linked immuno assays.The correlation between HMGB1 expression and other clinicopathologic parameters was analyzed byχ2 test,and the univariate as well as multivariate analyses were accomplished by Kaplan-Meier method and Coxregression model,respectively.RESULTS:Overall,overexpression of HMGB1 was found in 38/65(58.8%)IHCCs,whereas VEGF-C overexpression was present in 30/65(46.2%)cases.Overexpression of HMGB1 was significantly correlated with lymphatic microvessel density(P=0.031,r=0.268)and VEGF-C expression(P=0.041,r=0.254).With univariate analysis,both HMGB1(P=0.001)and VEGF-C(P=0.004)were identified to be significantly associated with overall survival rate.Multivariateanalysis indicated that HMGB1 could be served as an unfavorable independent prognostic factor in IHCCs(P=0.005).si RNA knockdown of HMGB1 inhibited transforming growth factor-β-induced epithelialmesenchymal transition(EMT)by elevating E-Cadherin expression and reducing expression of N-Cadherin,Vimentin and Snail in RBE cells.Further in vitro study revealed that HMGB1 silencing significantly decreased the level of VEGF-C,whereas the recombinant HMGB1increased the VEGF-C level in RBE cells(both P<0.05),which suggested that HMGB1 could promote lymphatic microvessel density,and subsequently lymphatic invasion,via promoting VEGF-C expression.CONCLUSION:Our results define an important role of HMGB1 in the progression of cholangiocarcinoma,and HMGB1 may serve as a prognostic marker for IHCC patients.

Dural puncture epidural technique provides better anesthesia quality in repeat cesarean delivery than epidural technique:Randomized controlled study

BACKGROUND Repeat cesarean deliverys involve a longer surgery and more severe visceral traction than primary cesarean deliverys.The dural puncture epidural(DPE)technique provides faster and more effective analgesia for labor,but there is no sufficient evidence to indicate whether it is suitable for parturients undergoing repeat cesarean delivery.AIM To determine the efficacy and safety of the DPE anesthesia technique in patients undergoing repeat cesarean delivery.METHODS Patients undergoing repeat cesarean delivery were randomly divided into the DPE and epidural anesthesia(EA)groups.A 25-G spinal needle was used for dural puncture via a 19-G epidural needle.The patients in the two groups were injected with 5 mL of 2%lidocaine followed by 15 mL of a mixture of 1%lidocaine+0.5%ropivacaine as the epidural dosage.The primary outcome was the onset time of sensory block to the T6 dermatome level and the sensory and motor block degree.RESULTS A total of 115 women were included(EA:57,DPE:58).The mean time to sensory block to the T6 Level was significantly shorter in the DPE group than in the EA group(14.7 min vs 16.6 min;95%confidence interval,13.9 to 15.4 vs 15.8 to 17.4;P=0.001).The cranial sensory block level was significantly higher at 5,10,and 15 min after the initial dose in the DPE group than in the EA group(P<0.05).The sacral sensory block level was significantly higher and the modified bromage score was significantly lower in the DPE group at each time point(P<0.05).Adverse effects and neonatal outcomes were comparable between the two groups(P>0.05).CONCLUSION The DPE technique provided higher-quality anesthesia than the EA technique,with a rapid onset of surgical anesthesia,better cranial and sacral sensory block spread and a higher motor block degree,without increasing the incidence of maternal or fetal side effects in patients undergoing repeat cesarean delivery.

The Arctic Sea Ice Thickness Change in CMIP6’s Historical Simulations

This study assesses sea ice thickness(SIT)from the historical run of the Coupled Model Inter-comparison Project Phase 6(CMIP6).The SIT reanalysis from the Pan-Arctic Ice Ocean Modeling and Assimilation System(PIOMAS)product is chosen as the validation reference data.Results show that most models can adequately reproduce the climatological mean,seasonal cycle,and long-term trend of Arctic Ocean SIT during 1979-2014,but significant inter-model spread exists.Differences in simulated SIT patterns among the CMIP6 models may be related to model resolution and sea ice model components.By comparing the climatological mean and trend for SIT among all models,the Arctic SIT change in different seas during 1979-2014 is evaluated.Under the scenario of historical radiative forcing,the Arctic SIT will probably exponentially decay at-18%(10 yr)-1 and plausibly reach its minimum(equilibrium)of 0.47 m since the 2070s.

Boosting ferroptosis and microtubule inhibition for antitumor therapy via a carrier-free supermolecule nanoreactor

Traditional microtubule inhibitors fail to significantly enhance+e effect of colorectal cancer;hence,new and efficient strategies are necessary.In+is study,a supramolecular nanoreactor(DOC@TA-Fe^(3+))based on tannic acid(TA),iron ion(Fe^(3+)),and docetaxel(DOC)wi+microtubule inhibition,reactive oxygen species(ROS)generation,and gluta+ione peroxidase 4(GPX4)inhibition,is prepared for ferroptosis/apoptosis treatment.After internalization by CT26 cells,+e DOC@TA-Fe^(3+)nanoreactor escapes from+e lysosomes to release payloads.+e subsequent Fe^(3+)/Fe^(2+)conversion mediated by TA reducibility can trigger+e Fenton reaction to enhance+e ROS concentration.Additionally,Fe^(3+)can consume gluta+ione to repress+e activity of GPX4 to induce ferroptosis.Meanwhile,+e released DOC controls microtubule dynamics to activate+e apoptosis pa+way.+e superior in vivo antitumor efficacy of DOC@TA-Fe^(3+)nanoreactor in terms of tumor grow+inhibition and improved survival is verified in CT26 tumor-bearing mouse model.+erefore,+e nanoreactor can act as an effective apoptosis and ferroptosis inducer for application in colorectal cancer+erapy.

Expression of p53, p21^(CIP1/WAF1) and eIF4E in the adjacent tissues of oral squamous cell carcinoma:establishing the molecular boundary and a cancer progression model

The present study evaluated the expression of key molecules and the status of DNA in both oral squamous cell carcinoma（OSCC） and adjacent tissues to establish a molecular surgical boundary and provide a cancer progression model. Biopsy samples from 50 OSCC patients were divided into T（cancer）, P1（0–0.5 cm）, P2（0.5–1 cm）, P3（1–1.5 cm） and P4（1.5–2 cm） groups based on the distances from the visible boundary of the primary focus. Twenty samples of normal mucosa were used as controls. We used immunohistochemical staining and flow cytometry to evaluate p53, p21CIP1/WAF1, e IF4 E and Ki-67 expression and to determine DNA status, respectively. Sub-mucosal invasion was present in the P1 and P2 groups as determined by haematoxylin and eosin staining.Mutant p53 expression decreased gradually from cancerous to normal mucosae, whereas p21CIP1/WAF1 expression displayed an opposite trend. e IF4 E expression decreased from cancerous to normal mucosae. Ki-67 expression, the heteroploidy ratio, S-phase fraction and proliferative index decreased gradually with the distance from the tumour centre. Based on these results, we suggest that the resection boundary in OSCC surgery should be beyond 2 cm from the tumour. Additionally, the adjacent tissues of the primary focus could be used as a model for assessing cancer progression.

Global Land Surface Climate Analysis Based on the Calculation of a Modified Bowen Ratio

A modified Bowen ratio(BRm),the sign of which is determined by the direction of the surface sensible heat flux,was used to represent the major divisions in climate across the globe,and the usefulness of this approach was evaluated. Five reanalysis datasets and the results of an offline land surface model were investigated. We divided the global continents into five major BRm zones using the climatological means of the sensible and latent heat fluxes during the period 1980–2010:extremely cold,extremely wet,semi-wet,semi-arid and extremely arid. These zones had BRm ranges of(-∞,0),(0,0.5),(0.5,2),(2,10) and(10,+∞),respectively. The climatological mean distribution of the Bowen ratio zones corresponded well with the K ¨oppen-like climate classification,and it reflected well the seasonal variation for each subdivision of climate classification. The features of climate change over the mean climatological BRm zones were also investigated. In addition to giving a map-like classification of climate,the BRm also reflects temporal variations in different climatic zones based on land surface processes. An investigation of the coverage of the BRm zones showed that the extremely wet and extremely arid regions expanded,whereas a reduction in area was seen for the semi-wet and semi-arid regions in boreal spring during the period 1980–2010. This indicates that the arid regions may have become drier and the wet regions wetter over this period of time.

Design and dynamic analysis of a scissors hoop-rib truss deployable antenna mechanism

As the support mechanism of space-borne antennas,space deployable antenna mechanism belongs to complex multi-closed-loop coupling mechanism,configuration design and dynamic analysis are more difficult than general parallel mechanism.In this paper,an unequal-length scissors mechanism(ULSM)is proposed by changing the position of the internal rotational joint through a basic scissors mechanism.A scissors hoop-rib truss deployable antenna mechanism(SHRTDAM)is constructed by replacing the parabolic rib with the ULSM.Kinematic analysis of SHRTDAM is conducted,and the degree of freedom(DOF)of the whole antenna mechanism is analyzed based on screw theory,the result showed that it has only one DOF.Velocity and acceleration characteristics of SHRTDAM are obtained by the screw derivative and rotation transformation.Based on Lagrange equation,dynamic model of this mechanism is established,the torque required to drive the mechanism is simulated and verified by Adams and MATLAB software.In addition,a ground experiment prototype of 1.5-m diameter was fabricated and a deployment test is conducted,which demonstrated the mobility and deployment performance of the whole mechanism.The mechanism proposed in this paper can provide a good reference for the design and analysis of large aperture space deployable antennas.

Prognostic and proliferative evaluation of ameloblastoma based on radiographic boundary

Ameloblastoma is a benign odontogenic tumor with an aggressive biological behavior,and the surgical treatment frequently results in failure for the postoperative recurrence.The aim of this article was to investigate whether the proliferative ability and prognosis of ameloblastoma could be evaluated by the radiographic boundary.The ameloblastoma cases treated by the conservative therapy in our hospital between 1981 and 2001 were divided into three groups based on the nature of the radiographic borders of the lesions.The biologic behavior was evaluated by Ki-67 antibody immunohistochemically.Comparisons of prognosis and Ki-67 expression were carried out by statistic methods.There were 24 cases of well-defined edge with sclerosis（group I）,41 cases of well-defined edge without sclerosis（group II） and 32 cases of ill-defined edge（group III）.The recurrent rates were 29.2% in group I,43.9% in group II and 62.5% in group III（P,0.05）.The cells in group III expressed the highest Ki-67 level（P,0.05）.The radiographic boundary could be used as one of indicators in evaluating the proliferative ability of ameloblastoma and the patient＇s prognosis,which was consistent with Ki-67 expression.

新工科背景下应用化学专业产教深度融合育人模式的探索与实践

新工科建设是服务国家战略发展新需求的重要举措,是工程教育改革创新的新起点。中国地质大学(武汉)应用化学专业依托地质、资源与环境学科优势,通过“金专”铺路、“金课”引领、铸“金实践”等措施,开展了产教深度融合育人模式的探索与实践,满足新工科背景下理工复合型应用化学专业人才培养要求。

Neurophysiological, histological, and behavioral characterization of animal models of distraction spinal cord injury: a systematic review

Distraction spinal cord injury is caused by some degree of distraction or longitudinal tension on the spinal cord and commonly occurs in patients who undergo corrective operation for severe spinal deformity.With the increased degree and duration of distraction,spinal cord injuries become more serious in terms of their neurophysiology,histology,and behavior.Very few studies have been published on the specific characteristics of distraction spinal cord injury.In this study,we systematically review 22 related studies involving animal models of distraction spinal cord injury,focusing particularly on the neurophysiological,histological,and behavioral characteristics of this disease.In addition,we summarize the mechanisms underlying primary and secondary injuries caused by distraction spinal cord injury and clarify the effects of different degrees and durations of distraction on the primary injuries associated with spinal cord injury.We provide new concepts for the establishment of a model of distraction spinal cord injury and related basic research,and provide reference guidelines for the clinical diagnosis and treatment of this disease.

Planning and construction of Xiong’an New Area(city of over 5 million people):Contributions of China’s geologists and urban geology

China established Xiong’an New Area in Hebei Province in 2017,which is planned to accommodate about 5 million people,aiming to relieve Beijing City of the functions non-essential to its role as China’s capital and to expedite the coordinated development of the Beijing-Tianjin-Hebei region.From 2017 to 2021,the China Geological Survey(CGS)took the lead in multi-factor urban geological surveys involving space,resources,environments,and disasters according to the general requirements of“global vision,international standards,distinctive Chinese features,and future-oriented goals”in Xiong’an New Area,identifying the engineering geologic conditions and geologic environmental challenges of this area.The achievements also include a 3D engineering geological structure model for the whole area,along with“one city proper and five clusters”,insights into the ecology and the background endowment of natural resources like land,geothermal resources,groundwater,and wetland of the area before engineering construction,a comprehensive monitoring network of resources and environments in the area,and the“Transparent Xiong’an”geological information platform that is open,shared,dynamically updated,and three-dimensionally visualized.China’s geologists and urban geology have played a significant role in the urban planning and construction of Xiong’an New Area,providing whole-process geological solutions for urban planning,construction,operation and management.The future urban construction of Xiong’an New Area will necessitate the theoretical and technical support of earth system science(ESS)from various aspects,and the purpose is to enhance the resilience of the new type of city and to provide support for the green,low-carbon,and sustainable development of this area.

Fixed-Time Antidisturbance Consensus Tracking for Nonlinear Multiagent Systems With Matching and Mismatching Disturbances

In this paper,fixed-time consensus tracking for mul-tiagent systems(MASs)with dynamics in the form of strict feed-back affine nonlinearity is addressed.A fixed-time antidistur-bance consensus tracking protocol is proposed,which consists of a distributed fixed-time observer,a fixed-time disturbance observer,a nonsmooth antidisturbance backstepping controller,and the fixed-time stability analysis is conducted by using the Lyapunov theory correspondingly.This paper includes three main improvements.First,a distributed fixed-time observer is developed for each follower to obtain an estimate of the leader’s output by utilizing the topology of the communication network.Second,a fixed-time disturbance observer is given to estimate the lumped disturbances for feedforward compensation.Finally,a nonsmooth antidisturbance backstepping tracking controller with feedforward compensation for lumped disturbances is designed.In order to mitigate the“explosion of complexity”in the tradi-tional backstepping approach,we have implemented a modified nonsmooth command filter to enhance the performance of the closed-loop system.The simulation results show that the pro-posed method is effective.

Low-temperature replacement construction of three-dimensional corrosion-resistant interface for deeply rechargeable Zn metal batteries

Aqueous Zn batteries are promising candidates for grid-scale renewable energy storage.Foil electrodes have been widely investigated and applied as anode materials for aqueous Zn batteries,however,they suffer from limited surface area and severe interfacial issues including metallic dendrites and corrosion side reactions,limiting the depth of discharge(DOD)of the foil electrode materials.Herein,a low-temperature replacement reaction is utilized to in-situ construct a three-dimensional(3D)corrosion-resistant interface for deeply rechargeable Zn foil electrodes.Specifically,the deliberate low-temperature environment controlled the replacement rate between polycrystalline Zn metal and oxalic acid,producing a Zn foil electrode with distinct 3D corrosion-resistant interface(3DCI-Zn),which differed from conventional two-dimensional(2D)protective structure and showed an order of magnitude higher surface area.Consequently,the 3DCI-Zn electrode exhibited dendrite-free and anticorrosion properties,and achieved stable plating/stripping performance for 1000 h at 10 mA cm^(-2)and 10 mAh cm^(-2)with a remarkable DOD of 79%.After pairing with a MnO2cathode with a high areal capacity of 4.2 mAh cm^(-2),the pouch cells delivered 168 Wh L^(-1)and a capacity retention of 89.7%after 100 cycles with a low negative/positive(N/P)ratio of 3:1.

基于和法思想探析赵晓平教授治疗胆石症经验

胆石症是发生于胆道系统的常见病、多发病,随着人们饮食结构和生活习惯的改变,其发病率呈逐年递增趋势,严重威胁人类健康。目前,关于胆石症的治疗仍以手术为主。手术治疗虽然见效快,但因其术后残石率、并发症率和复发率高,治疗效果往往不尽如人意。陕西省名中医赵晓平基于自身多年中医临床实践经验,提出基于“和法”思想的指导下运用经方治疗外科常见疾病,继承创新,中西并举,在中西医结合治疗胆石症方面疗效显著。

Fluid property identification of the Lower Cretaceous reservoirs with complex oil-water contacts in Deseo Basin,Chad

Recently,exploration breakthroughs have been made in the Lower Cretaceous sandstone reservoirs in the Doseo Basin,but the identification of reservoir fluid property is difficult due to variable reservoir lithology,complex oil-water contact within and faint responses of the oil zone,which causes the lower accuracy of reservoir fluid property identification with conventional mudlogging and wirelogging techniques.Applying the geochemical logging,fluorescent logging,mud logging and cutting logging technology,in combination with formation test data,this paper distinguishes the crude oil types,analyzes the logging response characteristics of oil zone after water washing,and establishes the interpretation charts and parameter standards for reservoir fluid properties.The crude oil can be divided into two types,namely viscous-heavy and thin-light,based on total hydrocarbon content and component concentration tested by mud logging,features of pyrolysis gas chromatogram and fluorescence spectroscopy.The general characteristics of oil layers experienced water washing include the decrease of total hydrocarbon content and component concentration from mud logging,the decrease of S1 and PS values from geochemical logging,the decrease of hydrocarbon abundance and absence of some light components in pyrolysis gas chromatogram,and the decrease of fluorescence area and intensity from fluorescence logging.According to crude oil types,the cross plots of S1 versus peak-baseline ratio,and the cross plots of rock wettability versus fluorescence area ratio are drawn and used to interpret reservoir fluid property.Meanwhile,the standards of reservoir fluid parameter are established combining with the parameters of PS and the parameters in above charts,and comprehensive multiparameter correlation in both vertical and horizontal ways is also performed to interpret reservoir fluid property.The application in the Doseo Basin achieved great success,improving interpretation ability of fluid property in the reservoir with complex oil-water contact,and also provided technical reference for the efficient exploration and development of similar reservoirs.

Understanding the dehydrogenation properties of Mg(0001)/MgH_(2)(110)interface from first principles

Magnesium hydride is one of the most promising solid-state hydrogen storage materials for on-board application.Hydrogen desorption from MgH_(2) is accompanied by the formation of the Mg/MgH_(2) interfaces,which may play a key role in the further dehydrogenation process.In this work,first-principles calculations have been used to understand the dehydrogenation properties of the Mg(0001)/MgH_(2)(110) interface.It is found that the Mg(0001)/MgH_(2)(110) interface can weaken the Mg-H bond.The removal energies for hydrogen atoms in the interface zone are significantly lower compared to those of bulk MgH_(2).In terms of H mobility,hydrogen diffusion within the interface as well as into the Mg matrix is considered.The calculated energy barriers reveal that the migration of hydrogen atoms in the interface zone is easier than that in the bulk MgH_(2).Based on the hydrogen removal energies and diffusion barriers,we conclude that the formation of the Mg(0001)/MgH_(2)(110) interface facilitates the dehydrogenation process of magnesium hydride.

从土地整治到国土综合整治:目标、框架与模式

当前中国正处于生态文明建设的重点时期,对土地整治提出新要求,上升到国土综合整治阶段,亟须厘清国土综合整治的内涵、目标、运行机制、理论框架与实践路径。本文系统地回顾了土地整治到国土综合整治的发展历程,在分析土地整治的成效与现状的基础上,引出国土综合整治的必要性,基于DPSI(驱动力—压力—状态—影响)模型揭示了从土地整治到国土综合整治发展背后的运行机制。基于'创新、协调、绿色、可持续'理念,提出了国土综合整治理论框架与实践路径,国土综合整治需由政府主导、市场推动、社会公众参与这三方动力共同衔接,部门协调,整合资金,以消除国土资源及其统筹利用中的障碍性因素,针对城市化地区、农村地区、重点生态功能区、矿产资源开发集中区、海岸带与海岛区域进行整治,以达到国土资源利用优化布局、生态友好可持续的目标。

基于关联规则和聚类分析中医药在肿瘤免疫治疗中的用药规律

目的通过关联规则、聚类分析的方法探讨中医药在肿瘤免疫治疗中的用药规律。方法以“免疫治疗”and“中医/中药”为检索词,通过检索2005年1月—2020年12月中国期刊全文数据库(CNKI)肿瘤免疫治疗中运用中医药的文献,运用Excel 2019建立数据库、SPSS Molder 18.0进行关联分析、SPSS statistics 26.0进行聚类分析,探索中医药在肿瘤免疫治疗的用药规律。结果经筛选剔除重复,共纳入文献53篇,纳入方剂88首,累计用药217味,累计频次742次。其中使用频次≧10次的中药共15味,频次共计280次(38.88%),应用频次最多的为补虚药(黄芪、白术、当归、人参、白芍、党参、熟地黄、山药、甘草)占比约60.00%。其次为利水渗湿药(茯苓、薏苡仁)占比约13.00%,理气药(陈皮)、化痰药(半夏)、破血逐瘀药(莪术)及清热解毒药(白花蛇舌草)占比基本一致,约为7.00%。使用频次≥10次的药物从药性分析:温(53.33%)、平(26.66%)应用频率较高;从药味分析:甘(66.66%)、辛(20.00%)、苦(13.33%)频率较高。从药对出现频次和药物组合关联规则分析发现,黄芪-白术(20)出现频次最高,且关联性最强。从药物的社团分析发现,黄芪、白术、茯苓、甘草、白芍、陈皮为其中的核心药物。结论以黄芪-白术为代表的益气健脾中药在肿瘤免疫治疗中应用最多,可能是通过提高机体免疫应答,起到增强肿瘤免疫治疗的效果。

基于网络药理学探究大黄治疗脑水肿作用机制

目的 基于网络药理学方法探究大黄对脑水肿的治疗作用及其机制。方法 运用中药系统药理学分析平台数据库(TCMSP)获取大黄活性成分及作用靶点,在Uniprot数据库寻找大黄靶基因,并与GeneCards、OMIM及TTD等数据库筛选得到的脑水肿疾病靶点,通过建立药物靶基因与疾病靶点venn图寻找共有基因靶点;运用Bisogent对共有基因靶点进行蛋白相互作用(PPI)网络分析,运用拓扑方法分析关键靶点及药物-成分-靶点网络中的关键成分。通过Metascape对共有基因靶点进行GO分析及KEGG分析,构建靶点-疾病-通路关联图,揭示高频药物治疗脑水肿的潜在作用机制。结果 通过TCMSP获得大黄30种活性成分,113个靶点;脑水肿疾病靶点1 691个,二者共同靶点共45个,其中较为关键的活性成分包括2-羟基丙酸、芦荟大黄素、β-谷甾醇、L-羟基丁酸、泽兰黄醇等;关键靶点包括HSP90AA1、APP、ESR1、CUL3、HSP90AB1、XPO1、EGFR等。涉及的传导途径主要包括癌症蛋白多糖通路、雌激素信号通路、神经活性配体-受体相互作用通路等。结论 研究表明大黄治疗脑水肿的作用机制可能与抑制细胞凋亡、氧化应激和炎症反应相关。