功能高分子引发生物矿化实现肿瘤阻断治疗

作为一种不依赖于肿瘤组织渗透的治疗策略，阻断疗法通过阻碍肿瘤与周围微环境之间的物质交换而有效抑制肿瘤的生长和转移。然而，血管阻断、细胞外基质构建等手段存在系统毒性大、肿瘤杀伤不完全、有效持续时间短等问题。受生物体矿化过程的启发，在肿瘤周围构筑生物矿化层成为一种新兴、安全、有效且持久的肿瘤阻断治疗创新模式。基于此，本研究团队首先将阿仑膦酸钠（ALN）键合到1,2-二硬脂酰基-sn-甘油-3-磷酸乙醇胺-N-聚乙二醇-琥珀酰亚胺酯（DSPE-PEG-NHS）的末端，合成了功能高分子DSPE-PEG-ALN。其中，DSPE端可以插入到细胞膜上，另一端的双膦酸可以高效吸附环境中的钙离子等阳离子而引发矿物沉积的连锁反应，在肿瘤周围形成生物矿化层，阻断肿瘤进展。为了进一步提高矿化策略的选择性，我们设计并合成了肿瘤酸度触发的引发生物矿化的聚氨基酸纳米粒子（BINP）。在中性条件下，BINP上的长烷基链组装在纳米粒子的内部，而在肿瘤组织的弱酸性环境中暴露，实现肿瘤细胞膜的特异性插入，原位引发生物矿化，选择性阻断肿瘤进展。原位引发生物矿化功能高分子的设计和应用为肿瘤阻断治疗提供了具有临床应用前景的创新思...     

葡萄糖敏感苯硼酸基高分子纳米药物传输体系

近年来,智能葡萄糖敏感自调式药物传递系统备受关注。这种智能药物释放系统能够模拟胰腺分泌胰岛素的生理模式而精准调控药物释放并控制血糖水平,在糖尿病治疗中具有良好的应用前景。其中,苯硼酸(PBA)功能化的葡萄糖敏感高分子纳米载体成为近年来的研究热点之一。该类材料具有体系稳定、可长期储存、可逆的葡萄糖敏感性能等优势。根据响应因素不同,葡萄糖敏感药物传递系统可分为pH响应、温度响应和光响应等类型。本文重点介绍了基于PBA的葡萄糖敏感高分子纳米药物载体的发展过程、性能和应用,并对该领域的发展前景进行了展望。     

Traffic resource allocation for complex networks

In this paper, an optimal resource allocation strategy is proposed to enhance traffic dynamics in complex networks. The network resources are the total node packet-delivering capacity and the total link bandwidth. An analytical method is developed to estimate the overall network capacity by using the concept of efficient betweenness (ratio of algorithmic betweenness and local processing capacity). Three network structures (scale-free, small-world, and random networks) and two typical routing protocols (shortest path protocol and efficient routing protocol) are adopted to demonstrate the performance of the proposed strategy. Our results show that the network capacity is reversely proportional to the average path length for a particular routing protocol and the shortest path protocol can achieve the largest network capacity when the proposed resource allocation strategy is adopted.     

A traffic flow cellular automaton model to considering drivers’ learning and forgetting behaviour

It is known that the commonly used NaSch cellular automaton (CA) model and its modifications can help explain the internal causes of the macro phenomena of traffic flow.However,the randomization probability of vehicle velocity used in these models is assumed to be an exogenous constant or a conditional constant,which cannot reflect the learning and forgetting behaviour of drivers with historical experiences.This paper further modifies the NaSch model by enabling the randomization probability to be adjusted on the bases of drivers’ memory.The Markov properties of this modified model are discussed.Analytical and simulation results show that the traffic fundamental diagrams can be indeed improved when considering drivers’ intelligent behaviour.Some new features of traffic are revealed by differently combining the model parameters representing learning and forgetting behaviour.     

抗肿瘤纳米材料

<正>蓬勃发展的纳米材料为肿瘤的安全高效治疗提供了有潜力的平台,其主要应用于肿瘤精确诊断、药物靶向递送、微环境调控和自身免疫系统激活等方面^[1-2]。本文简述了该领域发表于《应用化学》上的最新研究成果,并展望了抗肿瘤纳米材料在临床应用中的机遇与挑战。     

环境税费政策下快递包装材料回收利用的最优决策及社会福利分析

本文在一个两阶段的决策模型中研究了政府环境税收政策下快递包装材料的回收利用问题,通过比较快递服务商在不同经营策略下的总利润和碳排放总量,刻画出不同环境税费水平下的最优经营策略选择。研究结果表明,当快递包装材料回收再利用的固定投资成本过高时,随着环境税费水平的不断升高,快递服务商并不一定总是选择绿色经营策略。此外,在这种情况下快递服务商即使选择了绿色经营策略也并不能总是带来碳排放的减少和环境的改善。而如果政府能够进行适当的固定投资补贴,则可有效地促进快递服务商选择并保持绿色经营策略,并且能够实现经济发展与环境保护的双赢。在引入单位碳排放的外部性成本后,本文分析了社会福利最大化下的最优环境税费水平。算例分析显示,政府的政策干预有可能同时实现社会福利最大化、快递服务商总利润的增加和碳排放总量的减少。     

聚(L-谷氨酸)微球的制备及其口服药物控释研究

通过正己胺引发γ-苯甲基-L-谷氨酸酯-N-内羧酸酐(BLG-NCA)开环聚合制备聚(γ-苯甲基-L-谷氨酸酯)(PBLG), 并进一步脱掉苯甲基保护得到聚(L-谷氨酸)(PLG). 以利福平为模型药物, 通过油包油(O/O)无水乳液法制备了PLG载药微球. 扫描电子显微镜检测表明该载药微球具有良好的球形形貌且粒径分布较均一, 粒径大小约为9.0 μm. 体外释放实验表明该载药微球对利福平的释放具有明显的pH敏感性, 在模拟胃液中较少释放利福平, 而在模拟肠液中较快并大量释放利福平, 符合口服药物载体释放性能的要求, 可用于口服药物的定位肠溶性载体. 此外, 噻唑蓝实验表明该微球具有良好的生物相容性.     

Effects of node buffer and capacity on network traffic

In this paper, we study the optimization of network traffic by considering the effects of node buffer ability and capacity. Two node buffer settings are considered. The node capacity is considered to be proportional to its buffer ability. The node effects on network traffic systems are studied with the shortest path protocol and an extension of the optimal routing [Phys. Rev. E 74 046106 (2006)]. In the diagrams of flux-density relationships, it is shown that a nodes buffer ability and capacity have profound effects on the network traffic.     

Constant evacuation time gap: Experimental study and modeling

In this paper, the evacuation dynamics in an artificial room with only one exit is investigated via experiments and modeling. Two sets of experiments are implemented, in which pedestrians are asked to escape individually. It is found that the average evacuation time gap is essentially constant. To model the evacuation dynamics, an improved social force model is proposed, in which it is assumed that the driving force of a pedestrian cannot be performed when the resultant physical force exceeds a threshold. Simulation results are in good agreement with the experimental ones.