Multifunctional Mesoporous Silica Nanoparticles for Cancer‐Targeted and Controlled Drug Delivery

Multifunctional mesoporous silica nanoparticles are developed in order to deliver anticancer drugs to specific cancer cells in a targeted and controlled manner. The nanoparticle surface is functionalized with amino‐β‐cyclodextrin rings bridged by cleavable disulfide bonds, blocking drugs inside the mesopores of the nanoparticles. Poly(ethylene glycol) polymers, functionalized with an adamantane unit at one end and a folate unit at the other end, are immobilized onto the nanoparticle surface through strong β‐cyclodextrin/adamantane complexation. The non‐cytotoxic nanoparticles containing the folate targeting units are efficiently trapped by folate‐receptor‐rich HeLa cancer cells through receptormmediated endocytosis, while folate‐receptor‐poor human embryonic kidney 293 normal cells show much lower endocytosis towards nanoparticles under the same conditions. The nanoparticles endocytosed by the cancer cells can release loaded doxorubicin into the cells triggered by acidic endosomal pH. After the nanoparticles escape from the endosome and enter into the cytoplasm of cancer cells, the high concentration of glutathione in the cytoplasm can lead to the removal of the β‐cyclodextrin capping rings by cleaving the pre‐installed disulfide bonds, further promoting the release of doxorubicin from the drug carriers. The high drug‐delivery efficacy of the multifunctional nanoparticles is attributed to the co‐operative effects of folate‐mediated targeting and stimuli‐triggered drug release. The present delivery system capable of delivering drugs in a targeted and controlled manner provides a novel platform for the next generation of therapeutics.     

基于FPGA的新型Walsh码发生器的设计与实现

介绍了一种离散Walsh函数的新型构造方法,然后给出了采用这种新方法设计的Walsh码发生器的电路框图,并给出了该设计的FPGA(现场可编程门阵列)器件实现方法,最后用Verilog HDL语言编程和QuartusⅡ开发软件进行了仿真验证.结果表明,该方法十分简便,电路结构简单,成本低,应用在CDMA(码分多址)通信系统中能明显减少带宽,提高频带的利用率,实用性好.     

Wait, focus and spray: efficient data delivery in wireless sensor networks with ubiquitous mobile data collectors

With decrease in the cost and the size of sensor devices, we can envision a world of ubiquitous sensor networks. Usually, sensor data needs to be disseminated from the source to data collectors, making the spatially distributed sensor data available for applications. The widespread and ubiquitous nature of mobile devices, e.g., PDAs and cell phones around the world, makes them attractive to be used as mobile data collectors (MDCs) to collect and deliver the sensor data. The goal of this work is to design a dissemination protocol that leads to efficient data delivery from the source sensors to ubiquitous MDCs. We propose the Wait-Focus-Spray (WFS) data delivery scheme for wireless sensor networks with ubiquitous MDCs. The main objective of WFS is to balance the data delivery latency and transmission overhead when considering the existence of ubiquitous MDCs. In WFS, we also propose a corresponding mechanism-probabilistic scattered binary spraying (PSBS), to reduce the spatial redundancy when spraying data copies, which can increase the probability of meeting a MDC. We then present an analytical model based on the Markov chain model to analyze the trade-off between delivery latency and transmission cost in WFS. Through extensive simulations, we demonstrate that our proposed scheme reduces the transmission cost per message while provides comparable delivery delay compared with the alternative approach.     

LTE核心网中基于PCC的QoS控制和能力开放技术研究

在LTE核心网中,通过引入PCC机制,来实现应用层业务数据流QoS需求到核心网承载层QoS分组过滤器之间的一致性映射和匹配问题。文章在详细介绍和分析LTE核心网中承载层QoS机制和PCC总体架构的基础上,研究如何将二者结合起来实现基于PCC和网络能力开放平台的QoS控制,从而提升运营商掌控网络提供业务的能力并改善用户的业务体验。     

ElGamal类型数字签名方案的安全性研究

给出了攻击ElGamal类型数字签名方案的一种方法,揭示了签名所需时间与随机参数k取值之间的关系,指出当k值较小时,此类签名方案是不安全的。     

无线上网新技术——WAP

Ｉｎｔｅｒｎｅｔ和移动通信已经在全球迅猛发展,无线上网成为必然趋势,ＷＡＰ论坛所制定的ＷＡＰ协议充分应用Ｉｎｔｅｒｎｅｔ的思想,支持多种目前及将来的无线网络,寿命用户在移动中使用各种目前仅在有线方式下方可使用的服务。本文介绍了ＷＡＰ的技术背景、设计思想和系统结构,并分析了ＷＡＰ对业界和人们的影响。     

激光二极管线列阵与多模光纤列阵的光纤耦合

利用一段数值孔径(NA)较小的多模光纤作为一个低成本的微透镜,对激光二极管线列阵的大数值孔径方向准直,将激光二极管线列阵的输出光束耦合到多模光纤列阵中.激光二极管线列阵每个发光单元的光分别耦合到光纤列阵的单根光纤中.总的耦合效率和输出光功率分别为75%和15W.     

21世纪的质量经营

本文介绍了质量经营产生的背景,探讨了质量经营的内涵,归纳了质量经营的特点,分析了在市场经济条件下企业实施质量经营的必要性。并对我国企业推行质量经营问题,提出了作者独到的见解。     

放大电路中反馈类型的判断

反馈在电子技术中得到了广泛的应用,在放大电路中经常引入负反馈来改善电路的工作状态和性质。该文主要分析了反馈的几种类型及反馈类型的判别方法,通过一些简捷的判别方法可以快速判断一个放大电路是什么类型的反馈,以便对电路的性能有更好的了解。     

透紫玻璃与蓝宝石的热压粘结工艺研究

透射式GaN阴极组件是GaN紫外日盲型探测器的最关键部件之一。介绍了制备透射式GaN阴极组件的工艺难点,主要报道了透紫玻璃与蓝宝石的热压粘结工艺的原理和研制过程,并着重分析了热压粘结工艺中出现的问题,同时提出了拟定的解决方案。