Novel design to improve band to band tunneling and gate induced drain leakages (GIDL) in cylindrical gate all around (GAA) MOSFET

Microsystem Technologies - In this paper a cylindrical Dual Metal (DM) Dielectric Engineered (DE) Gate All Around (GAA) MOSFET has been proposed to resolve a big issue of Gate Inducted Drain...     

Microneedles for transdermal drug delivery: a systematic review

Transdermal route has been explored for various agents due to its advantage of bypassing the first pass effect and sustained release of drug. Due to strong barrier properties of the skin, mainly stratum corneum (SC), the delivery of many therapeutic agents across the skin has become challenging. Few drugs with specific physicochemical properties (molecular weight <500?Da, adequate lipophilicity, and low melting point) can be effectively administered via transdermal route. However, delivery of hydrophilic drugs and macromolecular agents including peptides, DNA and small interfering RNA is challenging. Drug penetration through the SC may involve bypass or reversible disruption of SC layer by various means. Recently, the use of micron-scale needles has been proposed in increasing skin permeability and shown to dramatically increase permeation, especially for macromolecules. Microneedles (MNs) can penetrate through the SC layer of the skin into the viable epidermis, avoiding contact with nerve fibers and blood vessels that reside primarily in the dermal layer. This review summarizes the types of MNs and fabrication techniques of different types of MNs. The safety aspects of the materials used for fabrication have been discussed in detail. Biological applications and relevant phase III clinical trials are also highlighted.     

DFuzzy: a deep learning-based fuzzy clustering model for large graphs

Graph clustering is successfully applied in various applications for finding similar patterns. Recently, deep learning- based autoencoder has been used efficiently for detecting disjoint clusters. However, in real-world graphs, vertices may belong to multiple clusters. Thus, it is obligatory to analyze the membership of vertices toward clusters. Furthermore, existing approaches are centralized and are inefficient in handling large graphs. In this paper, a deep learning-based model ‘DFuzzy’ is proposed for finding fuzzy clusters from large graphs in distributed environment. It performs clustering in three phases. In first phase, pre-training is performed by initializing the candidate cluster centers. Then, fine tuning is performed to learn the latent representations by mining the local information and capturing the structure using PageRank. Further, modularity is used to redefine clusters. In last phase, reconstruction error is minimized and final cluster centers are updated. Experiments are performed over real-life graph data, and the performance of DFuzzy is compared with four state-of-the-art clustering algorithms. Results show that DFuzzy scales up linearly to handle large graphs and produces better quality of clusters when compared to state-of-the-art clustering algorithms. It is also observed that deep structures can help in getting better graph representations and provide improved clustering performance.     

Analytical modeling of bidirectional multi‐channel IEEE 802.11 MAC protocols

This paper presents an analytical approach to model the bi‐directional multi‐channel IEEE 802.11 MAC protocols (Bi‐MCMAC) for ad hoc networks. Extensive simulation work has been done for the performance evaluation of IEEE 802.11 MAC protocols. Since simulation has several limitations, this work is primarily based on the analytical approach. The objective of this paper is to show analytically the performance advantages of Bi‐MCMAC protocol over the classical IEEE 802.11 MAC protocol. The distributed coordination function (DCF) mode of medium access control (MAC) is considered in the modeling. Two different channel scheduling strategies, namely, random channel selection and fastest channel first selection strategy are also presented in the presence of multiple channels with different transmission rates. M/G/1 queue is used to model the protocols, and stochastic reward nets (SRNs) are employed as a modeling technique as it readily captures the synchronization between events in the DCF mode of access. The average system throughput, mean delay, and server utilization of each MAC protocol are evaluated using the SRN formalism. We also validate our analytical model by comparison with simulation results. The results obtained through the analytical modeling approach illustrate the performance advantages of Bi‐MCMAC protocols with the fastest channel first scheduling strategy over the classical IEEE 802.11 protocol for TCP traffic in wireless ad hoc networks. Copyright © 2010 John Wiley & Sons, Ltd.     

Poly(acrylamide) functionalized chitosan: An efficient adsorbent for azo dyes from aqueous solutions

In the present communication we report on the optimization of persulfate/ascorbic acid initiated synthesis of chitosan-graft-poly(acrylamide) (Ch-g-PAM) and its application in the removal of azo dyes. The optimum yield of the copolymer was obtained using 16 × 10⁻² M acrylamide, 3.0 × 10⁻² M ascorbic acid, 2.4 × 10⁻³ M K₂S₂O₈ and 0.1 g chitosan in 25 mL of 5% aqueous formic acid at 45 ± 0.2 °C. Ch-g-PAM remained water insoluble even under highly acidic conditions and could efficiently remove Remazol violet and Procion yellow dyes from the aqueous solutions over a pH range of 3–8 in contrast to chitosan (Ch) which showed pH dependent adsorption. The adsorption data of the Ch-g-PAM and Ch for both the dyes were modeled by Langmuir and Freundlich isotherms where the data fitted better to Langmuir isotherms. To understand the adsorption behavior of Ch-g-PAM, adsorption of Remazol violet on to the copolymer was optimized and the kinetic and thermodynamic studies were carried out taking Ch as reference. Both Ch-g-PAM and Ch followed pseudo-second-order adsorption kinetics. The thermodynamic study revealed a positive heat of adsorption (ΔH°), a positive ΔS° and a negative ΔG°, indicating spontaneous and endothermic nature of the adsorption of RV dye on to the Ch-g-PAM. The Ch-g-PAM was found to be very efficient in removing color from real industrial wastewater as well, though the interfering ions present in the wastewater slightly hindered its adsorption capacity. The data from regeneration efficiencies for ten cycles evidenced the high reusability of the copolymer in the treatment of waste water laden with even high concentrations of dye.     

Detection of Single DNA Molecule Hybridization on a Surface by Atomic Force Microscopy

Improving the detection of DNA hybridization is a critical issue for several challenging applications encountered in microarray and biosensor domains. Herein, it is demonstrated that hybridization between complementary single‐stranded DNA (ssDNA) molecules loosely adsorbed on a mica surface can be achieved thanks to fine‐tuning of the composition of the hybridization buffer. Single‐molecule DNA hybridization occurs in only a few minutes upon encounters of freely diffusing complementary strands on the mica surface. Interestingly, the specific hybridization between complementary ssDNA is not altered in the presence of large amounts of nonrelated DNA. The detection of single‐molecule DNA hybridization events is performed by measuring the contour length of DNA in atomic force microscopy images. Besides the advantage provided by facilitated diffusion, which promotes hybridization between probes and targets on mica, the present approach also allows the detection of single isolated DNA duplexes and thus requires a very low amount of both probe and target molecules.     

Recent developments in cold plasma-based enzyme activity (browning,cell wall degradation,and antioxidant) in fruits and vegetables

According to the Food and Agriculture Organization of United Nations reports, approximately half of the total harvested fruits and vegetables vanish before they reach the end consumer due to their perishable nature. Enzymatic browning is one of the most common problems faced by fruit and vegetable processing. The perishability of fruits and vegetables is contributed by the various browning enzymes (polyphenol oxidase, peroxidase, and phenylalanine ammonia-lyase) and ripening or cell wall degrading enzyme (pectin methyl-esterase). In contrast, antioxidant enzymes (superoxide dismutase and catalase) assist in reversing the damage caused by reactive oxygen species or free radicals. The cold plasma technique has emerged as a novel, economic, and environmentally friendly approach that reduces the expression of ripening and browning enzymes while increasing the activity of antioxidant enzymes; microorganisms are significantly inhibited, therefore improving the shelf life of fruits and vegetables. This review narrates the mechanism and principle involved in the use of cold plasma technique as a nonthermal agent and its application in impeding the activity of browning and ripening enzymes and increasing the expression of antioxidant enzymes for improving the shelf life and quality of fresh fruits and vegetables and preventing spoilage and pathogenic germs from growing. An overview of hurdles and sustainability advantages of cold plasma technology is presented.     

A Simple Enzymatic Approach for Selective Acetylation of Phosphatidylethanolamine

Acetylation of lecithin improves the fluid properties, water dispersibility and emulsifying properties of a variety of food formulations. Acetylation of lecithin is usually carried out chemically using acetic anhydride in the presence of tertiary amine. In the present study acetylation of soybean lecithin and egg yolk lecithin was carried out using lipozyme IM 20 having 1,3-specificity from Mucor miehei and vinyl acetate at 70–75 °C. Vinyl acetate played a dual role as acetylating agent and also as the solvent medium. This method selectively acetylated phosphatidylethanolamine without effecting phosphatidylinositol since the enzyme employed was 1,3-specific.     

Transition Metal Ion–Mediated Tyrosine‐Based Short‐Peptide Amphiphile Nanostructures Inhibit Bacterial Growth

We report the design and synthesis of a biocompatible small‐peptide‐based compound for the controlled and targeted delivery of encapsulated bioactive metal ions through transformation of the internal nanostructures of its complexes. A tyrosine‐based short‐peptide amphiphile (sPA) was synthesized and observed to self‐assemble into β‐sheet‐like secondary structures. The self‐assembly of the designed sPA was modulated by application of different bioactive transition‐metal ions, as was confirmed by spectroscopic and microscopic techniques. These bioactive metal‐ion‐conjugated sPA hybrid structures were further used to develop antibacterial materials. As a result of the excellent antibacterial activity of zinc ions the growth of clinically relevant bacteria such as Escherichia coli was inhibited in the presence of zinc ? sPA conjugate. Bacterial testing demonstrated that, due to high biocompatibility with bacterial cells, the designed sPA acted as a metal ion delivery agent and might therefore show great potential in locally addressing bacterial infections.