DNA‐backbone radio resistivity induced by spin blockade effect

Coherent control of OH‐free radicals interacting with the spin‐triplet state of a DNA molecule is investigated. A model Hamiltonian for molecular spin singlet‐triplet resonance is developed. We illustrate that the spin‐triplet state in DNA molecules can be efficiently populated, as the spin‐injection rate can be tuned to be orders of magnitudes greater than the decay rate due to small spin‐orbit coupling in organic molecules. Owing to the nano‐second life‐time of OH free radicals, a non‐equilibrium free energy barrier induced by the injected spin triplet state that lasts approximately longer than one‐micro second in room temperature can efficiently block the initial Hydrogen abstraction and DNA damage. For a direct demonstration of the spin‐blockade effect, a molecular simulation based on an ab‐initio Car‐Parrinello molecular dynamics is deployed. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010     

A network efficiency measure with application to critical infrastructure networks

In this paper, we demonstrate how a new network performance/efficiency measure, which captures demands, flows, costs, and behavior on networks, can be used to assess the importance of network components and their rankings. We provide new results regarding the measure, which we refer to as the Nagurney–Qiang measure, or, simply, the N–Q measure, and a previously proposed one, which did not explicitly consider demands and flows. We apply both measures to such critical infrastructure networks as transportation networks and the Internet and further explore the new measure through an application to an electric power generation and distribution network in the form of a supply chain. The Nagurney and Qiang network performance/efficiency measure that captures flows and behavior can identify which network components, that is, nodes and links, have the greatest impact in terms of their removal and, hence, are important from both vulnerability as well as security standpoints.     

Efficient password authenticated key agreement using bilinear pairings

For providing a secure distributed computer environment, efficient and flexible user authentication and key agreement is very important. In addition to user authentication and key agreement, identity privacy is very useful for users. In this paper, we propose an efficient and flexible password authenticated key agreement scheme using bilinear pairings. The main merits include: (1) there is no need for any password or verification table in the server; (2) users can choose or change his own password freely; (3) both the server and a user can authenticate each other; (4) it can protect the user’s privacy; (5) the user and the server can generate a session key; (6) it does not have a serious synchronization-clock problem; (7) even if the secret information stored in a smart card is compromised, it can prevent the offline dictionary attack.     

宁波市天童森林公园的蟹蛛

在天童森林公园采集到蟹蛛科蜘蛛12属18种，其中加藤瘤蟹蛛（Phrynarachne katoi)为国内新纪录，缘弓蟹蛛（Alcimochthes limbatus)雄蛛为国内首次报道，缘弓蟹蛛（Alcimochthes limbatus)，条纹绿蟹蛛（Oxytate striatipes)，方花蟹蛛（Xyxticus quadratus)，三班花蟹蛛（Xysticus pseudoblitea)为浙江省次次报道。     

Synthesis and characterization of inexpensive 3-Nɛ-benzyloxycarbonyl-L-lysyl-morpholine-2,5-dione

In this paper, we call 3-N^ɛ-benzyloxycarbonyl-L-lysyl-morpholine-2,5-dione “Compound A”. The starting material used abroad is expensive and the yield is low (16%–28%); furthermore, to our best knowledge, no characterization of Compound A is available in the open literature. We now use low-cost L-lysine as starting material, succeed in raising the yield of Compound A to about 66%, and characterize it. In the synthesis of Compound A, the reactive processes used by us included the protection of amino group of lysine, acetylation, and intramolecular cyclizative condensation reaction. Benzoxycarbonyl chloride was selected as amino group protection agent, and the yield was elevated by replacing sodium bicarbonate with triethyl amide as the acid’s neutralizer. The resulting material or Compound A was cyclizative; its structure and properties were characterized by infrared (IR), Differential Scanning Calorimetry (DSC), Nuclear Magnetic Resonance (NMR) and elemental analysis. The results of characterization show that: (1) Compound A has a chiral carbon next to the carbonyl group, so the formation of the ring structure is not sterospecific; (2) the melting point is about 254.5°C. The homopolymer and copolymers of Compound A with lactide or caprolactone have reaction-active groups and excellent biocompatibility and biodegradability; so they can be used in tissue engineering and as controlled-drug-release carriers. Translated from Journal of Northwestern Polytechnical University, 2006, 24(4): 444–447 (in Chinese)     

A REVIEW OF STUDIES OF MECHANICAL PROPERTIES OF TURTLE CARAPACE 1)

历经上亿年,大多数龟类爬行动物均进化出了比重轻、强度高、韧性好的防护外壳。研究这些龟壳的结构特征和材料力学行为对安全防护结构的仿生设计有着重要启示。本文分别从龟壳的宏微观多尺度结构--功能关系、静动态力学性能和仿生应用三个方面介绍了近年来国内外的研究进展及现状。基于对上述研究现状的分析,本文还进一步展望了龟壳力学性能研究未来需关注的重点,以期能够更好地促进仿龟壳结构在安全防护领域的应用。     

Solubilization of active molecules in microemulsions for improved environmental protection

Various industries including food and pharmaceuticals are sharing increasing interest in microemulsions. Also, one can demonstrate that solubilization of active materials within the core or interface of microemulsions may have environmental benefits.

In this work, we report three examples of new microemulsion formulations specially designed to be capable of solubilizing active materials and protecting the environment from the emission of hazardous matter or protecting sensitive molecules from the detrimental effects of the environment.

In the first example, fire-resistant ingredients were incorporated in hydraulic fluids based on water-in-oil (W/O) microemulsions and their typical characteristics were described. In the second example, five-component oil-in-water (O/W) microemulsions were designed to solubilize lycopene and protect it from exposure to light. In the third example, a friendly solvent (butyl lactate) was microemulsified to form nanosized liquid droplets capable of solubilizing bromine-based bactericide formulations of sophisticated wood preservatives.

The new vehicles exhibit a very significant solubilization capacity and can be applied in aqueous media. In the last example, the active matter may be triggered when demanded and the release will be followed by film formation.     

宽防护角全息激光防护镜片

本文报道了全息激光防护镜的研制工作,并提出了双斜复合反射全息扩大防护角的方法。从实验结果看,对0.53μm激光的防护角可达30°,可见光透过率大于60%,其性能指标基本达到对眼睛的防护要求。     

近红外光谱的通用聚苯乙烯牌号在线识别方法

在聚合物加工过程中,如果在同一生产线上混用不同牌号的原材料,可能会影响产品性能,降低产品合格率。然而采用传统方法识别相同类型不同牌号的聚合物往往耗时长且具有滞后性,目前还缺乏一种快速实时的牌号识别方法。因此,以5种不同牌号的通用聚苯乙烯(GPPS)为研究对象,利用自主开发的安装于挤出机上的在线近红外光谱测量系统,将近红外光谱与化学计量学、机器学习算法相结合,实现对挤出过程中GPPS牌号的快速在线识别。首先利用在线近红外光谱测量系统实时采集5种不同牌号GPPS熔体的在线近红外光谱,波长范围为900~1 700 nm。经过谱图分析后,利用主成分分析结合K均值聚类算法验证在线近红外光谱数据对于不同牌号的可分性。最后采用偏最小二乘判别分析和随机森林两种算法分别建立GPPS牌号识别模型并进行对比。结果表明：①经过基线校正、最大最小归一化、7点移动平均平滑预处理后,在线近红外光谱在1 207,1 388,1 407和1 429 nm处的特征峰峰值会随着牌号的变化呈阶梯状改变,以前3个主成分得分作为K均值聚类的输入变量得到聚类正确率为88%,说明了不同牌号GPPS在线近红外光谱数据的可分性;②所建立的两种预测模型均能够对GPPS牌号有效识别,最佳主因子数为3的偏最小二乘判别分析模型对验证集的分类正确率为90.4%,以前5个主成分得分作为输入变量建立的随机森林模型对验证集的分类正确率达95.6%,所以随机森林模型的牌号识别性能更好。因此,在线近红外光谱测量系统结合化学计量学、机器学习算法可以实现GPPS牌号的快速在线识别,为在生产线上利用近红外光谱识别同种聚合物的不同牌号提供参考。