光致固液转变型偶氮苯聚合物的合成与光响应性能

偶氮苯聚合物由于其独特的光响应性能在光分子开关、信息存储等领域具有潜在的应用,但偶氮苯顺反异构化转变及光致固液转变的影响因素仍需要更深入的研究。文中设计并合成了4种偶氮苯聚合物,对比了偶氮苯相连的柔性链对其光响应性能的影响。研究发现,引入柔性链段使偶氮苯异构化时间从20 min降到100 s,同时含柔性链段的偶氮苯聚合物具有光致固液转变的能力,而不含柔性链段的偶氮苯聚合物不能发生光致固液转变。

为有效防控新冠病毒肺炎争取时间——抗疫假期政策对疫情传播的影响

在新发突发传染病的早期阶段,快速应对对于疫情防控至关重要。用于控制疫情的公共假期能为大规模、迅速地进行社会隔离和其他举措提供关键的时间窗口期。本研究的目的是探讨抗疫假期的起始时间节点和持续时间对中国早期新冠病毒肺炎疫情传播的影响。我们开发了一个房室模型来模拟从2020年1月开始中国新冠病毒肺炎疫情的动态传播;预测并比较了春节期间在有抗疫假期和没有抗疫假期下的疫情传播;考虑了抗疫假期在不同持续时间、不同起始时间节点,以及在关于病毒传播率的不同假设下的多种情况;估计了在不同情况下达到某些感染阈值所需的天数延迟。结果表明,中国的抗疫假期使新冠病毒肺炎疫情的传播停滞了许多天。与不设抗疫假期的场景相比,基础场景的抗疫假期(湖北省为21 d,中国所有其他省为10 d)可使确诊感染100000例的时间延迟7.54 d。持续时间更长的抗疫假期会对疫情防控产生更大的影响。为期21 d的全国性抗疫假期可使确诊感染100000例的时间延迟近10 d。此外,研究发现,在新发突发传染病较早阶段实施抗疫假期比较晚阶段实施对遏制疫情蔓延更有效,抗疫假期期间采取额外的控制措施可以增强疫情控制效果。总之,抗疫假期能够通过有效地减少人群的社交接触频率及范围,从而减缓疫情的传播。抗疫假期使得新冠病毒肺炎传播暂时停滞,为疫情防控争取了时间,科学家可用争取的时间来发现传播途径并确定有效的公共卫生干预措施,政府可用争取的时间来完善基础设施、调配医疗用品、培训和部署专业人力资源,从而为长期防控做好准备。

Progress in Nanocellulose Preparation and Application

Nanocellulose is a biodegradable, renewable, nonmeltable polymeric material that is insoluble in most solvents due to hydrogen bonding and crystallinity. Nanocellulose has attracted considerable attention in recent decades owing to its environmental friendliness, wide availability, good biocompatibility, high crystallinity, and high Young's modulus. This review presents the recent achievements in preparation and applications of nanocellulose, including a discussion of the advantages and disadvantages of various preparation methods and a summary of the applications of nanocellulose in composite materials research. Finally, we examine the mounting evidence of more widespread potential applications of nanocellulose.

Barriers and facilitators in Pre-exposure Prophylaxis(PrEP)use intention among Chinese homosexual men

Background:Despite strengthened efforts on human immunodeficiency virus(HIV)prevention and control,new HIV infections continue to increase among men who have sex with men(MSM)in China.Pre-exposure prophylaxis(PrEP),a highly effective HIV-prevention tool,has recently been included in China’s Action Plan of HIV Prevention and Control.To promote future PrEP implementation,this study aims to identify the barriers and facilitators in PrEP use intention among MSM in China.Methods:In 2018,a cross-sectional survey was conducted among 300 MSM in Nanjing,Jiangsu Province.Questions on demographics,sexual behavior(including a seven-item high-risk behavior index),PrEP use intention,PrEP-related awareness and accessibility,and a seven-item public HIV stigma scale were included in the questionnaire.Bivariate and multivariate logistic regression analyses were conducted to identify factors associated with PrEP use intention.Results:Overall,44.67%of the participants had more than two male sexual partners and 5.56%had HIV-positive sexual partners.Only 57.00%had heard of PrEP and only four(1.33%)participants had used PrEP.However,75.34%expressed the willingness to use oral PrEP if its efficacy was assured.The beliefs that“PrEP can prevent HIV if taken as prescribed”(adjusted odds ratio(AOR)=4.84,P<0.001)and“PrEP can be scaled up in the community”(AOR=3.24,P<0.001)were positively associated with oral PrEP use intention.Concerns of side effects were negatively associated with oral PrEP use intention(AOR=0.32,P=0.006).Further,77.00%of the participants would choose injectable or implanted PrEP instead of oral PrEP.One of the PrEP stigma items,“Not certain if doctors can prescribe PrEP if I go to the clinic”was positively associated with the intention to use injectable or implanted PrEP(AOR=3.03).The items“Heard of PrEP”(AOR=2.74)and“PrEP can prevent HIV if taken as prescribed”(AOR=2.65)were also positively related to the intention to use injectable or implanted PrEP.The most common concerns regarding PrEP use were efficacy(44.67%)and side effects(38.67%).The most common reasons for using injectable and implanted PrEP were adherence(81.94%and 77.86%,respectively)and privacy concerns(56.48%and 55.00%,respectively).Affordable price and coverage by health insurance were the driving factors for PrEP use.Conclusion:Given the low level of awareness of PrEP-related information in China,it’s necessary to provide interventions for high-risk individuals and communities,in order to increase their awareness and knowledge of PrEP.Furthermore,additional alternatives to HIV prevention,such as long-acting injectable or implanted PrEP,should be investigated to reduce the risk of HIV infection in at-risk MSM.Even if this programme could be approved by the National Medical Products Administration of China and implemented,a supportive social environment for MSM is essential during its implementing.

To Include Dyslipidemia Management into National Basic Public Health Service: from Project Practice to Policy

As cardiovascular diseases have been increasingly endangering the health and quality of life of Chinese residents,all relevant parties have been actively looking for policies and measures to effectively control the risk factors of the diseases.Hypertension and diabetes have been included in the National Basic Public Health Service Project since 2009;however,as one of the most crucial risk factors for cardio-cerebrovascular diseases,dyslipidemia has not yet been covered by the project due to various reasons.The prevalence of dyslipidemia in China increased rapidly from 18.6%in 2002 to 40.4%in 2012(1),whereas the management of dyslipidemia has been lagging behind and become the“short board”in the prevention and control of cardiocerebrovascular diseases.