可注射改性羧甲基纤维素水凝胶的制备及性能

对羧甲基纤维素(CMC)进行巯基接枝改性,制备了羧甲基纤维素衍生物(CMC-SH),采用溶解氧或H2O2氧化巯基(-SH)形成双硫键(-S-S-)的方法,化学交联制备了CMC-SH10、CMC-SH20和CMC-SH30系列可注射羧甲基纤维素基水凝胶,并对水凝胶的流变学性能以及在37℃的磷酸盐缓冲溶液(PBS)中的溶胀率、降解行为、体外药物释放行为进行了研究。结果表明,系列CMC-SH水凝胶具有较好的流变学性能,CMC-SH30水凝胶的储能模量(G′)和屈服应力(τ)分别达到2873Pa和9328Pa;在37℃的PBS溶液中,系列水凝胶均能快速达到溶胀平衡,8h溶胀率介于22~29之间;均具有较好的稳定性,13d降解率为28%~48%;药物模型牛血清蛋白(BSA)5d的累积释放率为45%~59%,对BSA具有较好的控释能力。总体而言,前驱体浓度越高,CMC-SH水凝胶的综合性能越好,系列水凝胶均具有较好的综合性能,其中CMC-SH30水凝胶的综合性能更好,有望应用于中短期蛋白类等大分子药物传输领域。

Decrease of GSK3βSer-9 Phosphorylation Induced Osteoblast Apoptosis in Rat Osteoarthritis Model

Nowadays,the cumulative intake of glucocorticoids has become the most common pathogenic factor for non-traumatic osteonecrosis of the femoral head(ONFH).Apoptosis of osteoblasts is considered as the main reason of ONFH at the molecular level.Glycogen synthase kinase 3β(GSK3β)is an important regulator of cellular differentiation and apoptosis pathway,which can modulate the balance between osteoblasts and osteoclasts.Several studies have reported about its function in osteoporosis,but little is known about it in osteonecrosis.In our study,lipopolysaccharide and methylprednisolone were utilized to establish a rat ONFH model.The phosphorylation of GSK3βSer-9 was decreased in the model.Western blotting examination ofβ-catenin,Bcl-2,Bax and caspase-3 revealed that the osteoblasts were apoptotic.In dexamethasone(Dex)-incubated primary osteoblasts,the expression profile of GSK3βphosphorylation and apoptotic factors were consistent with those in the rat ONFH model.To further investigate the regulation of osteonecrosis caused by GSK3β,the expression and function of GSK3βwere inhibited in Dex-incubated primary osteoblasts.The knockdown of GSK3βby siRNA decreased the expression of Bax and cleaved caspase-3,but increased Bcl-2 andβ-catenin.On the other hand,selective inhibition of GSK3βfunction by LiCl counteracted the activation of caspase-3 induced by Dex.Our work is the first study about the GSK3P phosphorylation in ONFH,and provides evidence for further therapeutic methods.

B原子掺杂调控CuIn纳米合金电子结构以实现电化学CO_(2)还原宽电位活性

杂原子掺杂可以调节电子结构以调整中间体吸附并优化反应路径,是设计高效CO_(2)还原反应(CO_(2)RR)催化剂的有应用前景的方法.B原子是常用的掺杂剂,引入B原子可以有效打破*COOH和OCHO*中间体的吉布斯自由能线性关系,并且可以通过与CO_(2)中O原子结合来增强CO_(2)吸附能力.B掺杂碳材料、单金属和金属氧化物的研究结果表明,B原子掺杂催化剂的CO_(2)RR活性和/或选择性有明显提高,然而多数报道的单个活性位点的B掺杂催化剂仅表现出在相对狭窄的电位范围内的CO_(2)RR高性能,设计制备CO_(2)RR的宽电位高选择性催化剂仍是巨大挑战.研究表明,合金化是提供多种类的活性位点相互协调和增强催化剂固有活性,进而改善CO_(2)RR性能并调节产物分布的可行策略.引入B原子到合金中以调节电子结构,最终优化关键中间体吸附的活性位点,对于寻找具有宽电位窗口的先进催化剂具有重要意义.本文提出了一种通过B掺杂调节CuIn合金电子结构以实现宽电位高选择性的电子工程策略.所制得的B掺杂CuIn合金(CuIn(B))在–0.6 V(vs.RHE)时表现出99%的CO法拉第效率(FECO),并在一个宽的阴极电化学窗口(400 m V)内保持了超过90%的较高FECO.同时,采用X射线光电子能谱(XPS)和CO_(2)吸附实验等手段研究了CuIn(B)性能提升的原因,结果表明,B原子与CuIn之间存在强烈的相互作用,改变了CuIn的电子结构.CO_(2)吸附结果表明,CuIn(B)比CuIn拥有更强的CO_(2)吸附能力,证明它具有潜在的快速CO_(2)RR反应动力学.进一步通过密度泛函理论(DFT)模拟研究了催化剂的热力学反应能量学以揭示CO_(2)RR机制,结果表明,*COOH更倾向于在CuIn(B)上形成,且*CO与CuIn(B)催化位点的结合强度最佳,更利于CO_(2)还原反应为CO,而CuIn更利于作为HER的活性位点;决速步骤是*CO中间体向CO转移,以实现高CO选择性;热力学限制电位研究表明,CuIn(B)大大提高了CO_(2)到CO转化的选择性.随后通过差分电荷密度研究也进一步证明了电荷转移过程是从CuIn位点到B位点.此外,根据d带理论,催化剂中Cu和In原子的投影态密度和d带中心(Ed)研究进一步证明了催化剂结构中的电子价态的变化,与XPS结果相符;引入B可以优化催化剂的电子结构,从而调节催化剂和中间体之间的结合能力,实现了CO_(2)RR在宽电位范围内的高活性和选择性.综上,本文对于电化学CO_(2)RR机理的基础理解和其实际应用具有促进作用.

Protective Effect of Human Umbilical Cord Mesenchymal Stem Cells in Glucocorticoid-induced Osteonecrosis of Femoral Head

Objective:To evaluate the effect of human umbilical cord mesenchymal stem cells(hUC-MSCs)on preventing rats from glucocorticoid-induced osteonecrosis of femoral head(GC-ONFH)in the early stage in vivo and to investigate the possible mechanism of hUC-MSCs in regulating the balance of osteogenesis and adipogenesis.Methods:All rats were randomly divided into 3 groups:control group(C group),model group(M group),and intervention group(Ⅰ group).The model of GC-ONFH was developed by a sequential administration of lipopolysaccharide and methylprednisolone.The rats in the Ⅰ group were treated with caudal vein injection of hUC-MSCs.Six weeks later,the blood samples were obtained to measure the activity of alkaline phosphatase(ALP)and the content of triglyceride(TG)in serum,and the femoral heads were harvested and observed by hematoxylin-eosin staining,Micro-CT,Western blot and real-time quantitative polymerase chain reaction.Results:After intervention of hUC-MSCs,the necrosis rate of femoral head decreased from 83%(10/12)to 33%(4/12),the rate of empty bone lacuna was significantly decreased,the activity of ALP increased significantly,the content of TG decreased significantly,the bone density increased obviously,the expression of RUNX2 and Col Ⅰ increased significantly and the expression of PPARγ decreased significantly.Conclusion:These results revealed that caudal vein injection of hUC-MSCs can effectively reduce the incidence of GC-ONFH in rats by increasing ALP activity and reducing TG content in serum,increasing bone mineral density,promoting the expression of RUNX2 and Col I,and inhibiting the expression of PPARγ.

Asymmetric Two-Component Alkenyl Catellani Reaction for the Construction of C—N Axial Chirality

Herein,we report an asymmetric two-component alkenyl Catellani reaction for the construction of C—N axial chirality through a palladium/chiral norbornene cooperative catalysis and an axial-to-axial chirality transfer process.Various partially aromatic iodinated 2-pyridones,quinolones,coumarin and uracil substrates react with 2,6-disubstituted aryl bromides with a tethered amide group,to afford a wide variety of polycyclic C—N atropisomers(38 examples,up to 97%e.e.).The obtained C—N axial chirality originates from the preformed transient C—C axial chirality with high fidelity.The synthetic utility of this chemistry is demonstrated by facile prepa-ration of complex quinoline and pyridine based C—N atropisomers through a N-deprotection and aromatization sequence.In addi-tion,a remote axial-to-central diastereoinduction process dictated by C—N axial chirality is observed with excellent diastereocontrol.

富氧燃烧方式下烟气中SO3和Hg的排放及控制研究进展

富氧燃烧技术可有效控制温室气体排放,是一种具有应用潜力的节能减排技术。本工作系统总结分析了富氧燃烧方式下关键烟气组分(SOx,NOx,H2O,Cl2/HCl等)对SO3和Hg排放规律的影响及飞灰对烟气中SO3吸附去除和Hg富集规律的影响,提出了富氧燃烧方式下较优的具可行性的污染物协同控制技术建议,为富氧燃烧技术工业应用面临的污染物协同控制提供重要参考。分析了目前富氧燃烧方式下SO3和Hg排放规律及优化控制研究存在的问题,对未来的研究方向提出了建议。要点:(1)富氧燃烧方式下烟气中SO3和Hg浓度明显提高。烟气中SOx,NOx,H2O,Cl2/HCl及飞灰等对SO3和Hg排放规律具有重要影响。(2)从脱硝、除尘、脱硫工艺优化方面,提出了富氧燃烧方式下具有可行性的污染物协同控制技术建议,为工业应用面临的污染物协同控制问题提供重要参考。(3)指出了未来富氧燃烧方式下SO3和Hg排放及优化控制的研究方向,如实际工况多因素耦合作用下排放规律、烟气中污染物的协同控制规律、关键污染物的迁移规律及协同控制工艺路线优化研究。

Axially Chiral Aryl-Alkene-lndole Framework: A Nascent Member of the Atropisomeric Family and Its Catalytic Asymmetric Construction

A new class of axially chiral aryl-alkene-indole frameworks have been designed,and the first catalytic asymmetric construction of such scaffolds has been established by the strategy of organocatalytic(Z/E)-selective and enantioselective(4+3)cyclization of 3-alkynyl-2-indolylmethanols with 2-naphthols or phenols(all>95:5 E/Z,up to 98% yield,97% ee).This reaction also represents the first catalytic asymmetric construction of axially chiral alkene-heteroaryl scaffolds,which will add a new member to the atropisomeric family.This approach has not only confronted the great challenges in constructing axially chiral alkene-heteroaryl scaffolds but also provided a powerful strategy for the enantioselective construction of axially chiral aryl-alkene-indole frameworks.

Design and synthesis of axially chiral aryl-pyrroloindoles via the strategy of organocatalytic asymmetric(2+3)cyclization

The catalytic asymmetric construction of axially chiral indole-based frameworks is an important area of research due to the unique characteristics of such frameworks.Nevertheless,research in this area is still in its infancy and has some challenges,such as designing and constructing new classes of axially chiral indole-based scaffolds and developing their applications in chiral catalysts,ligands,etc.To overcome these challenges,we present herein the design and atroposelective synthesis of aryl-pyrroloindoles as a new class of axially chiral indole-based scaffolds via the strategy of organocatalytic asymmetric(2+3)cyclization between 3-arylindoles and propargylic alcohols.More importantly,this new class of axially chiral scaffolds was derived into phosphines,which served as efficient chiral ligands in palladium-catalyzed asymmetric reactions.Moreover,theoretical calculations provided an in-depth understanding of the reaction mechanism.This work offers a new strategy for constructing axially chiral indole-based scaffolds,which are promising for finding more applications in asymmetric catalysis.

Evaluation of health benefit using Ben MAP-CE with an integrated scheme of model and monitor data during Guangzhou Asian Games

Guangzhou is the capital and largest city（land area：7287 km2）of Guangdong province in South China.The air quality in Guangzhou typically worsens in November due to unfavorable meteorological conditions for pollutant dispersion.During the Guangzhou Asian Games in November 2010,the Guangzhou government carried out a number of emission control measures that significantly improved the air quality.In this paper,we estimated the acute health outcome changes related to the air quality improvement during the 2010 Guangzhou Asian Games using a next-generation,fully-integrated assessment system for air quality and health benefits.This advanced system generates air quality data by fusing model and monitoring data instead of using monitoring data alone,which provides more reliable results.The air quality estimates retain the spatial distribution of model results while calibrating the value with observations.The results show that the mean PM2.5concentration in November 2010 decreased by 3.5μg/m^3 compared to that in 2009 due to the emission control measures.From the analysis,we estimate that the air quality improvement avoided 106 premature deaths,1869 cases of hospital admission,and 20,026 cases of outpatient visits.The overall cost benefit of the improved air quality is estimated to be 165 million CNY,with the avoided premature death contributing 90%of this figure.The research demonstrates that Ben MAP-CE is capable of assessing the health and cost benefits of air pollution control for sound policy making.

Design and demonstration of a next-generation air quality attainment assessment system for PM_(2.5)and O_3

Due to the increasingly stringent standards, it is important to assess whether the proposed emission reduction will result in ambient concentrations that meet the standards. The Software for Model Attainment Test-Community Edition （SMAT-CE） is developed for demonstrating attainment of air quality standards of O3 and PM2.5. SMAT-CE improves computational efficiency and provides a number of advanced visualization and analytical functionalities on an integrated GIS platform. SMAT-CE incorporates historical measurements of air quality parameters and simulated air pollutant concentrations under a number of emission inventory scenarios to project the level of compliance to air quality standards in a targeted future year. An application case study of the software based on the U.S. National Ambient Air Quality Standards （NAAQS） shows that SMAT-CE is capable of demonstrating the air quality attainment of annual PM2.5 and 8-hour O3 for a proposed emission control policy.

Development and case study of a science-based software platform to support policy making on air quality

This article describes the development and implementations of a novel software platform that supports real-time, science-based policy making on air quality through a user-friendly interface. The software, RSM-VAT, uses a response surface modeling（RSM） methodology and serves as a visualization and analysis tool（VAT） for three-dimensional air quality data obtained by atmospheric models. The software features a number of powerful and intuitive data visualization functions for illustrating the complex nonlinear relationship between emission reductions and air quality benefits. The case study of contiguous U.S.demonstrates that the enhanced RSM-VAT is capable of reproducing the air quality model results with Normalized Mean Bias 〈 2% and assisting in air quality policy making in near real time.

A case study of development and application of a streamlined control and response modeling system for PM_(2.5)attainment assessment in China

This article describes the development and application of a streamlined air control and response modeling system with a novel response surface modeling-linear coupled fitting method and a new module to provide streamlined model data for PM_（2.5） attainment assessment in China.This method is capable of significantly reducing the dimensions required to establish a response surface model,as well as capturing more realistic response of PM_（2.5） to emission changes with a limited number of model simulations.The newly developed module establishes a data link between the system and the Software for Model Attainment Test—Community Edition（SMAT-CE）,and has the ability to rapidly provide model responses to emission control scenarios for SMAT-CE using a simple interface.The performance of this streamlined system is demonstrated through a case study of the Yangtze River Delta（YRD） in China.Our results show that this system is capable of reproducing the Community Multi-Scale Air Quality（CMAQ） model simulation results with maximum mean normalized error 〈 3.5%.It is also demonstrated that primary emissions make a major contribution to ambient levels of PM_（2.5） in January and August（e.g.,more than50%contributed by primary emissions in Shanghai）,and Shanghai needs to have regional emission control both locally and in its neighboring provinces to meet China＇s annual PM_（2.5）National Ambient Air Quality Standard.The streamlined system provides a real-time control/response assessment to identify the contributions of major emission sources to ambient PM_（2.5）（and potentially O_3 as well） and streamline air quality data for SMAT-CE to perform attainment assessments.

A manoeuvre indicator and ensemble learning-based risky driver recognition approach for highway merging areas

Due to the complex traffic characteristics in highway merging areas,drivers tend to exhibit high-risk driving behaviours.To address the characteristics of driving behaviour in highway merging areas,we have developed a real-time identification model for risky drivers by combining a driver risk level labelling method with load balancing-ensemble learning(LB-EL).In this paper,we explore four types of manoeuvre indicator indexes(MIIs)—acute direction,stomp pedal,dangerous following and dangerous lane changing—that can describe the negative behaviours of both individual vehicles and vehicle platoons in highway merging areas.To quantize the label driver risk level,we use the interquartile range(IQR)method and Criteria Importance Though Intercriteria Correlation(CRITIC)while evaluating the reliability of the MII using spatial analysis.Furthermore,we balance the dataset using three load balancing(LB)algorithms and create nine ensemble strategies by pairing adaptive boosting(AdaBoost),extreme gradient boosting(XGBoost)and light gradient boosting machine(LGBM)with the three LB algorithms.Finally,we validate the proposed model using trajectory data extracted from unmanned aerial vehicle(UAV)videos.The results indicate that the distribution laws of risky driving behaviours in the acute direction and stomp pedal show a high degree of similarity and good matching with the distribution laws of traffic conflict points in existing research.Moreover,the synthetic minority over-sampling technique-light gradient boosting machine(SMOTE-LGBM)ensemble model achieves the best performance,reaching an accuracy rate of 93.4%,and a recall rate of 92.1%,which demonstrates the validity of our proposed model.This model can be widely applied to recognize risky drivers in video-based surveillance systems.