可见光激发下具有增强抑菌作用的聚乙烯醇/石墨氮化碳复合纳米纤维膜

将聚乙烯醇(PVA)溶液与分散在其中的石墨氮化碳(g-C_(3)N_(4))纳米片通过静电纺丝技术和交联反应成功地制备了具有增强抑菌性能的可生物降解复合纳米纤维膜。对PVA/g-C_(3)N_(4)(P-CN)复合纳米纤维膜的微观形貌、物理性能及抗菌性能进行了研究,分析了g-C_(3)N_(4)含量对复合纳米纤维膜的形貌及性能的影响。扫描电镜分析结果表明,P-CN纤维直径为200~300 nm,交联后纤维直径变为1μm左右,g-C_(3)N_(4)质量分数小于3%时,纳米片均匀地分布在纳米纤维的表面,通过拉伸和溶胀测试发现,交联复合纳米纤维膜具有良好的力学性能和优良的抗溶胀性能。抑菌测试结果表明,复合纳米纤维对大肠杆菌和金黄色葡萄球菌的抗菌效果随着g-C_(3)N_(4)含量的增加明显提高,在4×10^(4)Lux的LED光激发10min后培养24 h的P-CN-5的最大抗菌环直径可以达到20 mm。研究结果表明,P-CN复合纳米纤维膜含少量g-C_(3)N_(4)就具备优异的抗菌性能,未来在抗菌涂层和包装等领域有巨大的应用潜力。

光催化抑菌和降解有机物的聚乙烯醇/二氧化钛@氮化碳复合纳米纤维膜

文中将TiO_(2)与g-C_(3)N_(4)(CN)二元复合制备了异质结复合物TiO_(2)@g-C_(3)N_(4)(TCN),然后将聚乙烯醇(PVA)溶液和TCN按照不同比例混合,通过静电纺丝技术制备了5种PVA复合TCN纳米纤维膜(P-TCN)。对TCN和P-TCN膜的微观形貌、物理性能、光催化抑菌性能和降解有机物性能进行了研究。结果表明,TCN中TiO_(2)纳米颗粒镶嵌在CN的片层结构中,TCN的光吸收能力和电子空穴分离率较CN有大幅提高,TCN具有更高的光催化活性。P-TCN复合纳米纤维膜具有良好的热稳定性和力学性能,在可见光激发下对大肠杆菌和金黄色葡萄球菌有明显的抑制作用,其中P-TCN-5对大肠杆菌的抑菌圈达到10.6mm,平板计数法算出的抑菌率达到99.3%。另外,P-TCN复合纳米纤维膜在可见光照射下对染料具有良好的降解性能,P-TCN-5在6h对亚甲基蓝(MB)的降解率达到了79%。该复合膜良好的抑菌效果和光催化降解性能令其在降解污染物、抗菌器材、包装材料等领域具有广阔的应用前景。

中国西部绿色发展概念框架

综合绿色发展的国际经验,以自然资本、经济资本、社会资本与人力资本四大资本为核心,提出了中国西部地区绿色发展概念框架。中国西部地区绿色发展概念框架是以"发展中促转变,转变中谋发展"的良性循环发展原则为指导原则,分析西部地区社会经济发展及生态环境和自然资源保护两个方面在发展过程中相互促进和制约的关系,并根据西部地区当前经济资本、环境资本、社会资本以及人力资本数量,通过政府适当干预,如区域规划、区内调整,最终实现社会经济与生态环境和自然资源相协调的绿色发展。该框架综合考虑了中国西部在绿色发展道路上特有挑战与机遇,阐明了社会经济发展与资源环境承载力之间的相互作用机制,明确了中国西部地区"生态友好、社会包容和内生增长"的绿色发展目标。最后,本文针对该绿色发展框架提出了中国西部地区绿色发展的政策建议:提出"西部地区绿色发展战略"是当前西部地区绿色发展进程中最为迫切的需求,中央政府应当尽快制定和实施"西部地区绿色发展战略",同时西部地区政府在省级和地方层面将保护中国西部生态环境与区域扶贫开发相结合,加大对以提升西部地区人力资本为目的的各类工程的投入,强化区域绿色基础建设和生态服务供给,缓解西部地区贫困,提升区域绿色发展进程的速度和质量;开展财政体制机制改革,以提高各级财政资金的使用效率;结合各省发展需求与条件实施以生态城市为发展目标的可持续城镇化发展模式,制定差异化的城镇化发展战略;在西部地区重点和限制开发区尤其是贫困集中和区域发展潜力较大地区,鼓励具有区域特色的新型绿色产业的发展。在发展过程中不断加强制度创新以引导长期绿色发展。

Welfare effects of rural-urban land conversion on different aged land-lost farmers:exemplified in Wuhan city

Rural-urban land conversion is a universal phenomenon in the rapid process of economic development and urban growth.The welfare of farmers who lost their farmland attracted a widespread concern within the society and academia.However,further research about differentiated policies according to the characteristics of different farmer groups is still need to be conducted.This article divides the land-lost farmers into three age groups:younger than 45,45-65,and more than 65.It proposes a welfare index system including eight functional areas based on different age groups of affected farmers,taking four districts of Wuhan City as case study area.Fuzzy mathematics method is used to derive the aggregated welfare effect index.Our analysis show that the overall welfare levels of land-lost farmers of all age groups declined,but with a varying degree,with the level of welfare in those farmers who are 45-65 years old,younger than 45 years old,and older than 65 years old decreased by 18.7%,16.6%,and 12.7%,respectively.The direction and degree of effects on the functional activity index varies among different groups.Economic conditions,living environment,health,and social participation of all age groups decrease while social security and housing conditions increase.On the other hand,development opportunities,social communication,and leisure have different changing directions in different age stages.These results call for differentiated and tailor-made compensation policies for land-lost farmers,towards improving the welfare levels of all farmers and reduce the disparity among them.

The Effect of TCM Herbs on Mitochondrial Functions: The Linkage between Qi and Mitochondria

The linkage between Qi and mitochondria was investigated by exploring the effect of Traditional Chinese Medicine (TCM) Qi-invigorating herbs on mitochondrial function at the biochemical and molecular levels. Three Chinese herbs (Astragali radix, Herba cistanche, Panax ginseng) were used to treat cultured mouse kidney cells and the generation of adenosine triphosphate (ATP) was measured. The Qi-invigorating herb, Astragali radix, was selected for further study using additional biological and molecular parameters, including ATP, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), mtDNA copies, superoxide dismutase (SOD), glutathione (GSH), cell growth, cell viability and transcriptomes. We also chose two concentrations of Astragali radix to study the hormetic effect. The results indicated that: 1) Qi-invigorating herbs have significant effects on the function of mitochondria, with ATP production and the antioxidant capacity being significantly enhanced, and ROS levels being reduced, allowing for a more optimal oxidation environment. The effect of the herbs followed a hormetic curve with a stimulating effect at lower doses but an inhibiting effect at high doses;2) The growth of the cells was not affected despite numerous biochemical changes associated with mitochondrial function, indicating the powerful ability of mitochondria to maintain cellular homeostasis;3) The up-regulation of NOCT gene, related to nicotinamide adenine dinucleotide (NADH) synthesis, offers a molecular basis for the ATP-promoting effect of the Qi-invigorating herbs. This work provides additional insight into the efficacy of TCM herbs from a western perspective.

Opportunities and challenges for development of urbanization in Western China

Urban and rural dual structure in Western China is obvious.The economic development of the central cities is relatively quick while that of the rural areas is lagging behind.The speeding up of urbanization contributes to the intensively uncoordinated development of urban and rural areas.Besides,the eco-fragile environment,shortage of available water resources,adverse geographic location,and relatively backward social economy restrict the development of urbanization in Western China.However,Western China also has the advantages of backwardness.This paper analyzes the present situation and development trend of urbanization in Western China.The results show that Western China has basically formed a development pattern with"industry promotes agriculture and urban leads to village".Therefore,combined with the present situation of Western China,this paper describes and analyzes the opportunities and challenges that may appear in the process of urbanization in Western China,puts forward the development pattern in which urban and rural areas can gain mutual support and co-development,and provides related recommendations.

A Preliminary Study in the Effect of <i>Astragali radix</i>, a Qi-Invigorating Herb, on Mitochondria: Insights at Cellular Level and Mouse Tissues Level

Objectives: To explore the effects of Qi-invigorating herbs on mitochondrial function using cultured cells and animal organs. Methods: Using water extracts of Astragali radix, we investigated the effect of “Qi-invigoration” on M-1 renal cells and mouse organs in-vitro including total adenylate production (TAP), reactive oxygen species (ROS) levels, and mitochondrial membrane potential (MMP). We also examined the effect on antioxidant capacity by conducting an analysis of superoxide dismutase (SOD) and glutathione (GSH). Results: 1) Astragali radix increased mitochondrial TAP generation and decreased ROS levels in both mouse kidney tissues and M-1 renal cells. 2) Astragali radix also significantly increased MMP and GSH levels in M-1 cells, but in the kidney tissue, there was no significant change in MMP levels and a decrease in GSH levels. 3) Astragali radix stimulated TAP levels in the heart, spleen, lung, kidney and skeletal muscle tissue, which was accompanied by the reduction of ROS. 4) For the meridian organs that Astragali radix belongs to, the energy production and antioxidant capacity were boosted simultaneously. Conclusions: These results provide new insights for the biochemical basis of Qi-invigoration and the meridian tropism theory for this Qi-invigorating herb.

Transcriptome Analysis of Gene in Mouse M-1 Cells Revealing the Functional Mechanism of Astragali Radix Extract

Astragali Radix (AR), the dried root of legumes, belongs to the Qi-invigorating herbs in traditional Chinese medicine and plays an important role in the treatment of many diseases. In order to understand the mechanism of action of AR extract. We used AR extract to treat M-1, mouse kidney cells, and used transcriptome sequencing technology to detect the genomic transcription level of the cells under the action of AR at different concentrations and times. The results showed that after a low concentration of AR treatments on the cells, the expression of genes related to cell growth and cellular immune response changed significantly, among which multiple genes are related to mitochondrial function, while high concentrations of AR affected the expression of histones and disease-related genes. It showed that the low concentration of AR extract can achieve the effect of invigorating Qi by regulating the function of mitochondria. In addition, several important genes and pathways were identified as potential targets of AR activation. The research not only clarified the main molecular biological mechanism of AR invigorating Qi, but also provided experimental basis and cellular physiology reference for the further clinical application of AR.

魏晋南北朝时期的抄本传播及其影响研究

抄本,亦称“写本”,是我国古代历史长河中一种非常重要的文献载体形式。它产生于汉末,发展于魏晋南北朝时期。由于魏晋南北朝时期特殊的时代和历史背景,使得这一时期的抄本传播也别具特色。为了更深入地了解古代抄本传播的发展情况,文章梳理了魏晋南北朝时期抄本传播的发展概况,分析其特点和传播途径,并对其产生的深远影响进行了深入的分析与阐述,以期引起学界对魏晋南北朝时期抄本传播研究的重视。

谁会成为在线学习的赢家——K12学生在线自我调节学习能力及其影响

自我调节学习作为一种重要的学习策略对在线学习至关重要,学生能否在在线学习环境中取得成功在很大程度上取决于其在线自我调节学习能力,因此对K12学生在线自我调节学习开展研究对于促进基础教育领域在线教育实践发展具有重要指导意义。本研究以新冠肺炎疫情期间参与在线学习的981名中学生为研究对象收集数据,探究我国K12学生在线自我调节学习能力水平、差异及其对学生学习成果的影响。研究发现:(1)绝大多数学生的在线自我调节学习能力处于中等水平,高水平者较少。(2)学生在线自我调节学习能力在性别上不存在显著差异,但在年级和区域上存在显著差异,不同学段学生在线自我调节学习能力呈现出"两端低中间高"特征;不同地区学生在目标设置、环境建构、任务策略、时间管理、寻求帮助和努力调节六方面均存在显著差异,事后多重比较分析显示省会城市和地级市学生显著高于县城和农村地区学生。(3)多元回归分析发现学生在线自我调节学习能力对学习满意度和感知学习均有显著影响。基于以上研究发现,研究就如何促进学生在线自我调节学习能力发展提出了针对性建议。

A Global Analysis of the Relationship Between Urbanization and Fatalities in Earthquake-Prone Areas

Urbanization can be a challenge and an opportunity for earthquake risk mitigation.However,little is known about the changes in exposure(for example,population and urban land)to earthquakes in the context of global urbanization,and their impacts on fatalities in earthquake-prone areas.We present a global analysis of the changes in population size and urban land area in earthquake-prone areas from 1990 to 2015,and their impacts on earthquake-related fatalities.We found that more than two thirds of population growth(or 70%of total population in 2015)and nearly three quarters of earthquake-related deaths(or 307,918 deaths)in global earthquake-prone areas occurred in developing countries with an urbanization ratio(percentage of urban population to total population)between 20 and 60%.Holding other factors constant,population size was significantly and positively associated with earthquake fatalities,while the area of urban land was negatively related.The results suggest that fatalities increase for areas where the urbanization ratio is low,but after a ratio between 40 and 50%occurs,earthquake fatalities decline.This finding suggests that the resistance of building and infrastructure is greater in countries with higher urbanization ratios and highlights the need for further investigation.Our quantitative analysis is extended into the future using Shared Socioeconomic Pathways to reveal that by 2050,more than 50%of the population increase in global earthquake-prone areas will take place in a few developing countries(Pakistan,India,Afghanistan,and Bangladesh)that are particularly vulnerable to earthquakes.To reduce earthquake-induced fatalities,enhanced resilience of buildings and urban infrastructure generally in these few countries should be a priority.

BMA probability quantitative precipitation forecasting of land-falling typhoons in south-east China

The probability of quantitative precipitation forecast(PQPF)of three Bayesian Model Averaging(BMA)models based on three raw super ensemble prediction schemes(i.e.,A,B,and C)are established,which through calibration of their parameters using 1-3 day precipitation ensemble prediction systems(EPSs)from the China Meteorological Administration(CMA),the European Centre for Medium-Range Weather Forecasts(ECMWF)and the National Centers for Environmental Prediction(NCEP)and observation during land-falling of three typhoons in south-east China in 2013.The comparison of PQPF shows that the performance is better in the BMA than that in raw ensemble forecasts.On average,the mean absolute error(MAE)of 1 day lead time forecast is reduced by 12.4%,and its continuous ranked probability score(CRPS)of 1-3 day lead time forecast is reduced by 26.2%,respectively.Although the amount of precipitation prediction by the BMA tends to be underestimated,but in view of the perspective of probability prediction,the probability of covering the observed precipitation by the effective forecast ranges of the BMA are increased,which is of great significance for the early warning of torrential rain and secondary disasters induced by it.