Silk Fibroin Microspheres： Preparation and Application for Controlled Drug Delivery

Silk fibroin （SF）, a natural protein polymer, has several unique properties such as aqueous processability, biocompatibility, and biodegradability. Due to these advantageous properties, it is promising for applications in various fields, especially drug delivery. In this paper, the simple preparation of SF microspheres was discussed via self-assembly. Some of SF＇s physicochemical properties and morphology were also investigated. The results show that the morphology, size and size distribution of silk microspheres depend upon various processing parameters, especially including volume ratios among SF, ethanol and polyvinyl alcohol （PVA）. Regular silk microspheres were obtained in PVA solution when adjusting the volume ratios of silk to ethanol from 20：1 to 20： 9. We also found that SF microspheres with various appearances were formed by addition of different PVA solution concentrations under a constant silk solution to ethanol volume ratio. From the Fourier transform infrared spectroscopy（FTIR） of silk microspheres, it was found that introducing ethanol into the SF solution induced conformational change from random coil to β-sheet. Additionally, under the observation of scanning electron microscopy （ SEM）, the shape of self-assembled silk microspheres was determined to be spherical. Finally, SF＇s potential as drug delivery carriers was discussed in the experimental results.     

A multi-path routing algorithm of LEO satellite networks based on an improved ant colony system

Geography rectangle is used to reduce signaling overhead of the LEO satellite networks.Moreover,a multi-path routing algorithm based on an improved ant colony system （MPRA-AC） is proposed.Matrix indicating the importance of the link between satellites is introduced into MPRA-AC in order to find the optimal path more quickly.Simulation results show that MPRA-AC reduces the number of iterations to achieve a satisfactory solution.At the same time,the packet delivery ratio of LEO satellite networks when running MPRA-AC and DSR-LSN （dynamic source routing algorithm for LEO satellite networks） is compared.The packet delivery ratio is about 7.9％ lower when running DSR-LSN.Moreover,because of the mechanism of active load balancing of MPRA-AC,simulation results show that MPRA-AC outperforms DSR-LSN in link utilization when data packets are transmitted in the networks.     

深空通信中基于中继选择的文件传输协议

针对深空通信传播时延大、误码率高以及链路间歇性中断的问题,提出一种基于中继选择的深空文件传输协议。该协议将文件传输过程分为跳到跳发送和端到端重传2个阶段。在发送阶段,提出一种中继选择算法,通过分析天体运动规律选择合适的中继节点,并结合深空链路信道特点,分析链路丢包率和信道增益的关系,选择最优中继链路逐跳进行传输,降低丢包率进而减少重传次数;在重传阶段,目的端对数据包进行校验和检查,丢失的数据包通过端到端链路进行重传,保证文件的可靠传输。仿真结果表明,当端到端误码率大于10－5时,所提协议能有效减少重传次数,进而降低传输时延。在误码率为10－3时,与空间数据系统咨询委员会（consultative committee for space data systems,CCSDS）提出的文件传输协议（CCSDS file delivery protocol,CFDP）相比,该协议的传输时间缩短了40％,能较好地适应深空通信环境。     

Transdermal Delivery of Piroxicam by Surfactant Mediated Electroporation

A lipophilic, nonsteroidal antiinflammation drug, piroxicam, was administered by skin electroporation using short, high-voltage pulses. The transdermal delivery of piroxicam during the electroporation was buffered due to the higher partition in skin lipids than in aqueous environments, which is called entrapment. Entrapment is the main resistance to transdermal delivery of lipophilic drugs. Two types of surfactants were used to enhance the skin electroporation. Tween 80 （0.2 g/L） and sodium dodecyl sulphate （SDS, 3 mg/mL） improve the solubility and diffusion rate of the drug in the hydrophobic local transport regions and reduce the entrapment of piroxicam in the skin. The transdermal delivery rate of piroxicam is increased 30- to 50-fold. However, the entrapment of piroxicam in the skin still occurred when Tween 80 was added. The SDS provides higher and more stable transdermal delivery rates of piroxicam than Tween 80, and also reduces the entrapment of piroxicam in the skin.     

不同客户服务水平下补货发货模型的选择

考虑到客户等待成本在某种程度上反映了客户所要求达到的服务水平,研究了不同需求区域内,当客户所要求的服务水平不同时,VMI环境下的两个典型的库存补充与发货模型.这两个模型分别采用了基于时间和基于数量的整合补货发货策略,分析了供应商如何根据客户服务水平制定相应的发货和库存补充策略,才能使客户满意度达到最大,同时其自身效益也获得最优,初步确定出了一个补货发货策略的选择方法,并应用MATLAB仿真软件进行了计算.     

全毫米波异构网络混合回程及缓存协助内容传递方案

针对部分流行多媒体文件重复下载产生的额外流量消耗引起的网络阻塞问题,提出了一种混合自回程及缓存(hybrid self-backhaul and cache,HSBC)协助的内容传递方案。在同信道和全毫米波部署的异构网络中,基于配置因子η,部分小基站(small base station,SBS)配备缓存并按照流行度等级存储多媒体内容,而无缓存配备的SBS通过多天线宏基站的自回程为用户提供请求内容,毫米波技术的引入有效缓解了网络频谱稀缺问题。利用实际天线阵列方向图模型,研究了系统的覆盖概率、平均面积吞吐量和平均延迟。结果表明,HSBC协助系统相较传统自回程(traditional self-backhaul,TSB)协助系统获得的性能增益很大程度上取决于系统参数。据此,提出了一种自适应TSB-HSBC-SBS协助内容传递模型。当缓存SBS的当前比率因子小于阈值时,选择TSB-SBS协助模型;否则使用HSBC-SBS协助模型。     

动态页面加速传输算法的研究与实现

针对传统Web缓存技术不能加速动态页面传输的局限性,提出了一个新的动态页面缓存加速算法,实现对动态页面的网络传输加速功能,并且在现有的缓存加速系统squid上实现了该算法,最后对其进行了测试和结果分析．     

壳寡糖纳米载体细胞内递送EGFR脱氧核酶的研究

设计靶向EGFR mRNA的脱氧核酶(EGFR DRz),以壳寡糖(COS)为材料,建立了一种有效的纳米基因细胞内传递体系,并研究其介导的靶向EGFR的脱氧核酶在Hela细胞内的生物学效应.流式结果表明COS-EGFR DRz复合体转染效率为88.7%,与脂质体转染试剂的89.7%相比无显著差异.半定量RT-PCR结果显示,经壳寡糖纳米载体递送的EGFR DRz能有效地靶向切割Hela细胞内的EGFR mRNA,使其表达下降.进一步的流式分析显示细胞被阻滞在G0～G1期,并且出现凋亡现象,其中COS组的凋亡率为19.3%,大于对照组脂质体的凋亡率13.0%.研究表明,COS较脂质体有相似的转染效率和更低的毒性,是一种潜在的、有效的脱氧核酶递送载体.     

Effect of EGF1 peptides in directing nanoparticles to thrombi

In order to examine the effect of EGF1 peptides in directing nanoparticles to thrombi, the synthesized EGF1 peptide was conjugated to poly (ethyleneglycol)-poly (lactide) (PEG-PLA) nanoparticles (NP) to form EGF1-NP. A lipophilic fluorescent dye, coumarin-6, was incorporated into EGF1-NP so as to detect its loading and release capacity. The binding ability of EGF1-NP with TF-expressing cells was shown to be significantly higher than that of the non-conjugated NP. Following an intravenous administration, fluorescence was distributed along the vessel wall of the thrombosis regions in the model rats injected with coumarin-6-loaded EGF1-NP. The in vitro and in vivo results suggest that EGF1-NP is a promising drug delivery system for targeting cerebral thrombi.     

基于“虚拟物流”理念的文献传递协作平台建设

分析了＂虚拟物流＂理念运用到文献传递服务中的可行性,阐述了＂虚拟物流＂在文献传递协作平台中的应用模型,提出了基于＂虚拟物流＂理念的文献传递协作平台运行模块的设置。