Provably secure three-party key agreement protocol using Chebyshev chaotic maps in the standard model

Recently, several key agreement protocols based on Chebyshev chaotic maps have been proposed in the literature. However, they can normally achieve “heuristic” security, that is, once drawbacks are found in these protocols, they are either modified to resist the new attacks, or are discarded. Under these circumstances, it is necessary and significant to define standard security models that can precisely characterize the capabilities of the participants and a potent adversary. Hence, we propose to use public key encryption based on enhanced Chebyshev chaotic maps and pseudo-random function ensembles to construct an efficient three-party key agreement protocol under the standard model, in which the adversary is able to make a wider range of queries and have more freedom than the other proposed schemes. In the design of our protocol, we follow the ideas in the recent key agreement protocol of Yang and Cao’s. The proposed protocol is shown to be provably secure if decisional Diffie–Hellman problem, which is based on Chebyshev chaotic maps, is computationally infeasible. To the best of our knowledge, our protocol is the first provably secure 3PAKE protocol using Chebyshev chaotic maps under the standard model.     

基于特征重聚焦网络的多尺度近岸舰船检测

针对监控视频中的多尺度近岸舰船检测问题,提出了一种基于特征重聚焦网络的舰船目标检测算法,设计了由多维特征聚合模块(MFAM)与注意力特征重构模块(AFRM)组成的特征重聚焦策略.其中,MFAM基于输入的特征金字塔构建特征聚合块,进一步融合多尺度舰船不同层次特征的语义信息.AFRM基于多分支空洞卷积以及通道与空间注意力机制提升网络对目标非局部信息的表征和对背景干扰的抑制,并构建了用于目标检测的特征重聚焦金字塔.在Seaships7000舰船公开数据集上的实验结果表明,相比其他算法,本算法对监控视频中多尺度近岸舰船的检测效果更好.     

Paper-based electrochemiluminescent 3D immunodevice for lab-on-paper, specific, and sensitive point-of-care testing

Recent research on microfluidic paper-based analytical devices (μPADs) has shown that paper has great potential for the fabrication of low-cost diagnostic devices for healthcare and environmental monitoring applications. Herein, electrochemiluminescence (ECL) was introduced for the first time into μPADs that were based on screen-printed paper-electrodes. To further perform high-specificity, high-performance, and high-sensitivity ECL on μPADs for point-of-care testing (POCT), ECL immunoassay capabilities were introduced into a wax-patterned 3D paper-based ECL device, which was characterized by SEM, contact-angle measurement, and electrochemical impedance spectroscopy. With the aid of a home-made device-holder, the ECL reaction was triggered at room temperature. By using a typical tris(bipyridine)ruthenium-tri-n-propylamine ECL system, this paper-based ECL 3D immunodevice was applied to the diagnosis of carcinoembryonic antigens in real clinical serum samples. This contribution further expands the number of sensitive and specific detection modes of μPADs.     

A novel high selectivity chemiluminescence sensor for fenvalerate based on double-sided hollow molecularly imprinted materials

Novel fenvalerate double-sided hollow molecularly imprinted microspheres (fenvalerate-DHMIMs) were fabricated by in situ polymerization with the help of mesoporous silica microspheres (MSMs) in this paper for the very first time. Scanning electron microscope was employed to characterize the surface morphology of the fenvalerate-DHMIMs. Taking advantage of the quenching effect of fenvalerate on the luminol-H(2)O(2)-NaOH chemiluminescence system, a new model was established to determine fenvalerate by a highly selective flow injection chemiluminescence method. The traditional flow-through cell was replaced by a novel Y-shaped column. The chemiluminescence intensity was linear with fenvalerate concentration over the range of 5.0 × 10(-8) to 2.0 × 10(-5) g mL(-1) and the detection limit was 2.2 × 10(-8) g mL(-1). The relative standard deviation (RSD) for the determination of 2.0 × 10(-6) g mL(-1) fenvalerate was 1.4% (n = 11). The proposed method was applied to the determination of fenvalerate in real samples with satisfactory results.     

The impact of human activity patterns on asymptomatic infectious processes in complex networks

The study of the impact of human activity patterns on network dynamics has attracted a lot of attention in recent years. However, individuals’ knowledge of their own physical states has rarely been incorporated into modeling processes. In real life, for certain infectious processes, infected agents may not have any visible or physical signs and symptoms; therefore, they may believe that they are uninfected even when they have been infected asymptomatically. This infection awareness factor is covered neither in the classical epidemic models such as SIS nor in network propagation studies. In this article, we propose a novel infectious process model that differentiates between the infection awareness states and the physical states of individuals and extend the SIS model to deal with both asymptomatic infection characteristics and human activity patterns. With regards to the latter, we focus particularly on individuals’ testing action, which is to determine whether an individual is infected by an epidemic. The simulation results show that less effort is required in controlling the disease when the transmission probability is either very small or large enough and that Poisson activity patterns are more effective than heavy-tailed patterns in controlling and eliminating asymptomatic infectious diseases due to the long-tail characteristic.     

Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) elastomer via photo-initiated graft polymerization of poly(ethylene glycol)

Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) copolymer biomedical elastomer was covalently grafted with poly(ethylene glycol) methyl ether methacrylate (PEGMA) via a photo-initiated graft polymerization technique. The surface graft polymerization of SEBS with PEGMA was verified by ATR-FTIR and XPS. Effect of graft polymerization parameters, i.e., monomer concentration, UV irradiation time and initiator concentration on the grafting density was investigated. Comparing with the virgin SEBS film, the PEGMA-modified SEBS film presented an enhanced wettability and a larger surface energy. Besides, the surface grafting of PEGMA imparted excellent anti-platelet adhesion and anti-protein adsorption to the SEBS surface.     

The influence of high dielectric constant core on the activity of core-shell structure electrorheological fluid

The core-shell structural dielectric particles are applied widely in the electrorheological (ER) fluids. The properties of the dielectric core are critical factors influencing their ER activity. In this paper, we successfully synthesized two kinds of core-shell hydroxyl titanium oxalate (TOC) particles with SiO(2) and TiO(2) as core, respectively. The obtained core-shell structural SiO(2)-TOC and TiO(2)-TOC particles were well-dispersed spherical nanoparticles with ideal morphology and a narrow size distribution. Under DC electric fields, the TiO(2)-TOC ER fluid showed notable ER activity with a yield stress of about 96 kPa (at 4 kV/mm), which is 3 times of that SiO(2)-TOC ER fluid and outclassed the yield stress of the TOC ER fluid. The dielectric spectra indicated that the higher dielectric constant of TiO(2) core induces the stronger interaction between the neighboring particles, which contribute to the enhancement of ER activity.     

Synthesis and antisense properties of fluoro cyclohexenyl nucleic acid (F-CeNA), a nuclease stable mimic of 2'-fluoro RNA

We report the design and synthesis of 2'-fluoro cyclohexenyl nucleic acid (F-CeNA) pyrimidine phosphoramidites and the synthesis and biophysical, structural, and biological evaluation of modified oligonucleotides. The synthesis of the nucleoside phosphoramidites was accomplished in multigram quantities starting from commercially available methyl-D-mannose pyranoside. Installation of the fluorine atom was accomplished using nonafluorobutanesulfonyl fluoride, and the cyclohexenyl ring system was assembled by means of a palladium-catalyzed Ferrier rearrangement. Installation of the nucleobase was carried out under Mitsunobu conditions followed by standard protecting group manipulations to provide the desired pyrimidine phosphoramidites. Biophysical evaluation indicated that F-CeNA shows behavior similar to that of a 2'-modified nucleotide, and duplexes with RNA showed slightly lower duplex thermostability as compared to that of the more rigid 3'-fluoro hexitol nucleic acid (FHNA). However, F-CeNA modified oligonucleotides were significantly more stable against digestion by snake venom phosphodiesterases (SVPD) as compared to unmodified DNA, 2'-fluoro RNA (FRNA), 2'-methoxyethyl RNA (MOE), and FHNA modified oligonucleotides. Examination of crystal structures of a modified DNA heptamer duplex d(GCG)-T*-d(GCG):d(CGCACGC) by X-ray crystallography indicated that the cyclohexenyl ring system exhibits both the (3)H(2) and (2)H(3) conformations, similar to the C3'-endo/C2'-endo conformation equilibrium seen in natural furanose nucleosides. In the (2)H(3) conformation, the equatorial fluorine engages in a relatively close contact with C8 (2.94 ?) of the 3'-adjacent dG nucleotide that may represent a pseudo hydrogen bond. In contrast, the cyclohexenyl ring of F-CeNA was found to exist exclusively in the (3)H(2) (C3'-endo like) conformation in the crystal structure of the modified A-form DNA decamer duplex [d(GCGTA)-T*-d(ACGC)](2.) In an animal experiment, a 16-mer F-CeNA gapmer ASO showed similar RNA affinity but significantly improved activity compared to that of a sequence matched MOE ASO, thus establishing F-CeNA as a useful modification for antisense applications.     

离子色谱法检测食品添加剂焦碳酸二甲酯中的氯离子

建立离子色谱法检测食品添加剂焦碳酸二甲酯（DMDC）中的杂质氯离子的方法。样品用水溶解超声定容后,采用SH-AC-1阴离子交换柱（250mm×4．6mm,5μm）分离,抑制电导法检测。考察了淋洗液种类、浓度对氯离子与干扰离子分离度的影响。最佳色谱条件：以0．005mol／L的四硼酸钠水溶液为淋洗液,流速1．0mL／min。在此条件下,样品中的氯离子可以和其它干扰离子分离,而且分离度达3．0以上,峰形对称。在氯离子浓度为0．1～5．0mg／L的范围内,可获得良好的线性关系,线性相关系数大于0．999;氯离子检出限（S／N=3）达0．007mg／L,加标回收率为97．5％～98．9％。该方法可以用于食品添加剂DMDC中氯离子的测定。     

功能梯度截顶圆锥壳的热弹性弯曲精确解

研究了功能梯度材料截顶圆锥壳在横向机械载荷与非均匀热载荷同时作用下的变形问题. 基于经典线性壳体理论推导出了以横向剪力和中面转角为基本未知量的功能梯度薄圆锥壳轴对称变形的混合型控制方程. 假设功能梯度圆锥壳的材料性质为沿厚度方向按照幂函数连续变化的形式. 然后采用解析方法求解,得到了问题的精确解. 分别就两端简支和两端固支边界条件,给出了圆锥壳的变形随其载荷、材料参数等变化的特征关系曲线,重点分析和讨论了载荷参数与材料梯度变化参数对变形的影响.