Effect of postmolding heat treatment on in vitro properties of a polyanhydride implant containing gentamicin sulfate

A polyanhydride implant containing gentamicin sulfate was fabricated using a laboratory-scale injection-molding machine. After injection molding, the implants were subject to heat treatment at 60°C for various time periods with or without nitrogen protection. The impact of this heat treatment on the in vitro properties of the implants including copolymer molecular weights, mechanical properties, and in vitro drug-release profiles was investigated. This heat treatment caused a drastic drop in the molecular weight of the copolymer. Heating without nitrogen protection resulted in the hardening of the implant, but heating in the presence of nitrogen rendered the implant less rigid. It was also found that a faster in vitro drug release profile was shown by implants heated without nitrogen protection and a pronounced slowing down in drug release was exhibited by implants heated with nitrogen protection.     

水稻基因组MSAP指纹图谱构建及DNA甲基化修饰位点分离与鉴定

采用EcoR I和Hpa II/Msp I双酶切建立了适合于水稻基因组的甲基化敏感扩增多态性(MSAP)分析体系,在全基因组水平检测了水稻DNA甲基化修饰位点.以12对MSAP引物进行选择性扩增,共检测到甲基化修饰位点120个,"CCGG/GGCC"位点甲基化修饰比例为20.17%.对部分水稻基因组甲基化修饰位点进行回收,最终分离了55条存在甲基化位点变异的DNA序列,通过BLAST比对分析将其联配到水稻基因组序列上.分析表明,这些甲基化修饰位点主要集中于基因启动子区(47%)和第一外显子区(22%),在其侧翼序列中存在类似"CpG island" 典型序列特征的"CpG"二核苷酸成簇富集区.在此基础上,对应用MSAP技术分离水稻基因组DNA甲基化修饰位点的有效性以及水稻基因组序列中"CpG island"类似序列分布特征和生物意义进行了讨论.     

轴对称锥形件缩口成形非强制变形规律的研究

论述了轴对称圆筒件在锥形凹模中缩口时口部自由弯曲区的变形趋向,对3种变形模式进行了比较,并通过实例计算,证实了按自由弯曲变形模式计算口部应力与变形是合理性.     

A formal architectural model for logical agent mobility

The process of agent migration is the major difference between logical code mobility of software agents and physical mobility of mobile nodes in ad hoc networks. Without considering agent transfer, it would make little sense to mention the modeling of strong code mobility, which aims to make a migrated agent restarted exactly from the state when it was stopped before migration. From the perspective of system's architecture, this paper proposes a two-layer approach for the formal modeling of logical agent mobility (LAM) using predicate/transition (PrT) nets. We view a mobile agent system as a set of agent spaces and agents could migrate from one space to another. Each agent space is explicitly abstracted to be a component, consisting of an environmental part and an internal connector dynamically binding agents with their environment. We use a system net, agent nets, and a connector net to model the environment, agents, and the connector, respectively. In particular, agent nets are packed up as parts of tokens in system nets, so that agent transfer and location change are naturally captured by transition firing (token game) in Petri nets. Agent nets themselves are active only at specific places and disabled at all the other places in a system net. The semantics of such a two-layer LAM model is defined by transforming it into a PrT net. This facilitates the analysis of several properties about location, state, and connection. In addition, this paper also presents a case study of modeling and analyzing an information retrieval system with mobile agents.     

Wire-in-Wire TiO2/C Nanofibers Free-Standing Anodes for Li-Ion and K-Ion Batteries with Long Cycling Stability and High Capacity

Wearable and portable mobile phones play a critical role in the market,and one of the key technologies is the flexible electrode with high spe-cific capacity an...     

Studies on Lotus Genomics and the Contribution to Its Breeding

Lotus (Nelumbo nucifera), under the Nelumbonaceae family, is one of the relict plants possessing important scientific research and economic values. Because of this, much attention has been paid to this species on both its biology and breeding among the scientific community. In the last decade, the genome of lotus has been sequenced, and several high-quality genome assemblies are available, which have significantly facilitated functional genomics studies in lotus. Meanwhile, re-sequencing of the natural and genetic populations along with different levels of omics studies have not only helped to classify the germplasm resources but also to identify the domestication of selected regions and genes controlling different horticultural traits. This review summarizes the latest progress of all these studies on lotus and discusses their potential application in lotus breeding.     

Linear-Dispersion Division Multiple-Access for MIMO systems

Comprehensive study on novel Linear-Dispersion Division Multiple-Access（LDDMA） for multi-user uplink Multiple-Input Multiple-Output（MIMO）systems is proposed.In the new multiplexing scheme,each user’s information symbol is dispersed by a User-Specific Matrix（USM）both in space and time domain and linearly combined at base-station side.And a simple random search algorithm,based on capacity maximization criteria,is developed to generate a bank of USMs.Simulation results are presented to demonstrate the advantages of LDDMA.When the Bit Error Rate（BER） reaches 10^–3,the performance gains are 3dB and 5dB,compared with Time-Division Linear Dispersion Codes（TD-LDC）and BLAST,respectively.     

Preparation and properties of magnesium oxysulfate cement and its application as lost circulation materials

Loss of drilling fluids in large porous and fractured zones inevitably up-regulates the overall cost of drilling.As a type of acid-soluble cement,magnesium oxys...