Fast intrusion detection based on a non-negative matrix factorization model

In this paper, we present an efficient fast anomaly intrusion detection model incorporating a large amount of data from various data sources. A novel method based on non-negative matrix factorization (NMF) is presented to profile program and user behaviors of a computer system. A large amount of high-dimensional data is collected in our experiments and divided into smaller data blocks by a specific scheme. The system call data is divided into blocks by processes, while command data is divided into consecutive blocks with a fixed length. The frequencies of individual elements in each block of data are computed and placed column by column as data vectors to construct a matrix representation. NMF is employed to reduce the high-dimensional data vectors and anomaly detection can be realized as a very simple classifier in low dimensions. Experimental results show that the model presented in this paper is promising in terms of detection accuracy, computation efficiency and implementation for fast intrusion detection.     

Recent advances in the design,development, and targeting mechanisms of polymeric micelles for delivery of siRNA in cancer therapy

Small interfering RNA (siRNA) is a relatively novel nucleic acid-based therapy to treat diseases such as cancer. Nevertheless, substantial obstacles to its clinical applications have been reported, such as low cellular uptake, immunogenicity, off-target effects, and instability in physiological environments. The design of appropriate delivery vehicles capable of transporting siRNA to target cells has been pursued. Nanoparticles are extensively studied for the delivery of siRNA. Among the various nanocarriers, polymeric micelles have recently gained strong interest. Polymeric micelles of average nanometer size are straightforward to design and modify. Hydrophilic groups incorporated in the polymeric micelles can extend in vivo half-life of siRNA to ensure adequate accumulation in tumors, be exchanged for cations that electrostatically interact with siRNA, and be coupled to various ligands for cell-specific targeting. The polymeric micelle core provides stability and serves as a loading dock for drugs. In this review, the different types of polymers used, the design and characterization of polymeric micelles for siRNA delivery, and the established polymeric micelle targeting mechanisms are discussed.     

Imparting strength into nanofiberous yarn by adhesive bonding

Low strength is one of the main disadvantages of nanofibrous structures in some applications such as suture yarns. To overcome this matter, in the present research, a novel method was applied to improve the tensile properties of nanofiber yarns. For this purpose, nanofibers and particles of polyvinyl acetate (PVAc) were added as a hot melt adhesive to nanofiber yarns in order to initiate adhesive bonding between nanofibers by two approaches. In the first one, Nylon 66/ PVAc hybrid nanofiber yarn was produced in opposite charged nozzles set up. In another approach, PVAc particles were electrosprayed through one of the nozzles while nylon 66 nanofibers were producing through another one. Afterward, thermal treatment was carried out for 78 seconds on samples in different temperatures. The results indicate that tensile strength was improved up to 1.97 and 1.7 times in comparison to nylon 66 nanofiberous yarn by adding PVAc nanofibers and particles, respectively. FTIR analysis was also carried out to assess the hybrid sample composition after heat treatment.     

Diverse bio-sensing and therapeutic applications of plasmon enhanced nanostructures

Substantial advancements have been observed over the years in the research and development of Localized Surface Plasmon Resonance (LSPR). A variety of current and future applications involving anisotropic plasmonic nanoparticles include biosensors, photothermal therapies, photocatalysis, and various other fields. Amongst various other applications, plasmonic enhancements are deployed in Surface Enhanced Raman Spectroscopy (SERS) mediated bio-sensing, absorption spectroscopy based analyte quantification, and fluorescence spectroscopy-based biomolecular detection up to femtomolar level and even on the level of single molecules. LSPR based healthcare diagnostics and therapeutics have grown much faster than expected, with an increased number of published original research articles and reviews. Despite the extensive literature available, a comprehensive review with a focused emphasis on recent advances in the field of plasmonic particle anisotropy, plasmonic nanostructure, plasmonic coupling mediated enhanced LSPR intensity and their diverse applications in biosensing is needed. This article focuses on LSPR properties of anisotropic nanostructures like spherical gold nanoparticles (AuNP), gold nanorod (AuNR), gold nanostar (AuNs), gold nanorattles (AuNRT), gold nanoholes (AuNH), dimeric nanostructures and their role in plasmonic enhancements for targeted biosensing and therapeutic research. The contemporary state of the art biosensing development around SERS has also been discussed. A detailed literature analysis of recent development in micro-surgery, photothermal tumor killing, biosensor development for detection up to single molecule level, high-efficiency drug delivery are covered in this article. Furthermore, recent and advanced technologies including Spatially Offset Raman Spectroscopy (SORS), Surface Enhanced Resonance Raman Spectroscopy (SERRS), and Surface Enhanced Spatially Offset Raman Spectroscopy (SESORS) are presented citing their importance in biosensing. We complement this review article with relevant theoretical frameworks to understand finer nuances within the literature that is discussed.     

Synthesis and cyclic voltammetric behaviour of some 3-substituted thiophenes and pyrroles: Precursors for the preparation of conducting polymers

The syntheses are reported of a series of 3-substituted thiophenes and pyrroles bearing long-chain amide, polyether and acyl functionality. The alkoxy-thiophenes and α-ketopyrrole monomers are more easily oxidized than the alkyl-substituted thiophenes. Their anodic electrochemistry has been studied by cyclic voltammetry.     

Study of the modification of coal-tar pitch with p-methyl benzaldehyde

Coal-tar pitch is modified with p-methyl benzaldehyde (PMB) in the presence of p-toluene sulfonic acid (PTS). The main characteristics of the modified pitches such as coking value, softening point and solubility are studied in this paper. The molecular structures of the modified pitches are studied using FT-IR and ¹H-NMR spectroscopy techniques. In addition, the morphologies of the modified pitches are inspected with SEM, and the optical textures of resultant semi-cokes are characterized by polarized-light microscopy. Results show that the modified pitches have much higher coking value and β-resins content than the parent pitch. There exist many microfibers with a uniform distribution in the modified pitches. Moreover, the modification results in an improvement in the optical textures of resultant semi-cokes.     

戊二醛与链霉素反应动力学的光谱学研究

根据朗伯比尔定律,建立戊二醛与链霉素标准曲线,用紫外分光光度法测定不同温度、浓度和反应时间下反应物的吸光度,计算单位时间内反应物浓度变化,进而得到该反应的动力学方程。结果表明,戊二醛与链霉素的反应较容易进行,属于四级反应,反应速率与各自浓度的二次方成正比,反应速率方程为ν=K[C戊二醛]2[C链霉素]2,反应的表观活化能为21.06 k J/mol。