Physical and functional interactions between the herpes simplex virus UL15 and UL28 DNA cleavage and packaging proteins

Herpes simplex virus (HSV) DNA is cleaved from concatemers and packaged into capsids in infected cell nuclei. This process requires seven viral proteins, including UL15 and UL28. UL15 expressed alone displays a nuclear localization, while UL28 remains cytoplasmic. Coexpression with UL15 enables UL28 to enter nuclei, suggesting an interaction between the two proteins. Additionally, UL28 copurified with UL15 from HSV-infected cells after ion-exchange and DNA affinity chromatography, and the complex sedimented as a 1:1 heterodimer upon sucrose gradient centrifugation. These findings are evidence of a physical interaction of UL15 and UL28 and a functional role for UL15 in directing UL28 to the nucleus.     

Biological activity of carboxy-terminal gastrin analogs

Amidated forms of gastrin are derived by post-translational processing of a large precursor peptide and stimulate gastric acid secretion via the gastrin/CCK(B) receptor. Non-amidated biosynthetic intermediates may exert biological effects through other mechanisms, but their effect on gastric acid secretion is unclear. Amidated gastrins stimulate acid secretion mainly by releasing histamine from mucosal enterochromaffin-like cells. This study examines the effects on histamine release from the vascularly perfused rat stomach of amidated gastrin-17, COOH-terminal glycine-extended gastrin-17, gastrin-17 extended at the COOH-terminal including the remaining progastrin sequence, and carboxy-terminal progastrin fragments (SAEDEN and GRRSAEDEN). Carboxy-terminal extended gastrins induced histamine release which was inhibited by the gastrin/CCK(B) antagonist L-740,093, but had to be given in concentrations 100-fold higher than amidated gastrin-17 to produce comparable effects. These progastrin-derived peptides are found in high concentrations in some patients with the Zollinger-Ellison syndrome and may contribute to acid hypersecretion and other gastrin/CCK(B) receptor mediated responses.     

ARTIFICIAL NEURAL NETWORKS: PRINCIPLE AND APPLICATION TO MODEL BASED CONTROL OF DRYING SYSTEMS - A REVIEW

Abstract

This paper reviews the developments in the model based control of drying systems using Artificial Neural Networks (ANNs). Survey of current research works reveals the growing interest in the application of ANN in modeling and control of non-linear, dynamic and time-variant systems. Over 115 articles published in this area are reviewed. All landmark papers are systematically classified in chronological order, in three distinct categories; namely, conventional feedback controllers, model based controllers using conventional methods and model based controllers using ANN for drying process. The principles of ANN are presented in detail. The problems and issues of the drying system and the features of various ANN models are dealt with upto-date. ANN based controllers lead to smoother controller outputs, which would increase actuator life. The paper concludes with suggestions for improving the existing modeling techniques as applied to predicting the performance characteristics of dryers. The hybridization techniques, namely, neural with fuzzy logic and genetic algorithms, presented, provide, directions for pursuing further research for the implementation of appropriate control strategies. The authors opine that the information presented here would be highly beneficial for pursuing research in modeling and control of drying process using ANN     

Role of nanoscale AlN and InN for the microwave characteristics of AlGaN/(Al,In)N/GaN-based HEMT

A new AlGaN/GaN-based high electron mobility transistor (HEMT) is proposed and its micro-wave characteristics are discussed by introducing a nanoscale AlN or InN layer to study the potential improvement in their high frequency performance. The 2DEG transport mechanism including various sub-band calculations for both (Al,In) N-based HEMTs are also discussed in the paper. Apart from direct current characteristics of the proposed HEMT, various microwave parameters such as transconductance, unit current gain (h ₂₁ = 1) cut-off frequency (f _t ), high power-gain frequency (f _max). Masons available/stable gain and masons unilateral gain are also discussed for both devices to understand its suitable deployment in microwave frequency range.     

Effects of chemical reaction on free convection flow through a porous medium bounded by a vertical surface

The effect of a chemical reaction on a free convection flow through a porous medium bounded by a vertical infinite surface has been studied. Velocity, temperature, and concentration profiles have been obtained for different values of parameters like the Grashof number, Prandtl number, and the chemical reaction parameter in the presence of homogeneous chemical reaction of first order. It is observed that the velocity and concentration increase during a generative reaction and decrease in a destructive reaction. The same is true for the behavior of the fluid temperature. The presence of the porous media diminishes the temperature.     

Polymers from renewable resources. I. Castor oil-based interpenetrating polymer networks: Thermal and mechanical properties

A number of polyurethanes (PUs) were synthesized by reacting castor oil with toluene-2,4-diisocyanate and hexamethylene diisocyanate and varying the NCO/OH ratio. All these polyurethanes were reacted with some acrylic monomers like ethyl acrylate, n-butyl acrylate, ethyl methacrylate, and butyl methacrylate using a crosslinker ethylene glycol dimethyl-acrylate and benzoyl peroxide as the initiator. The physicochemical properties of interpenetrating polymer networks (IPNs) are reported. Thermogravimetric analysis was used to study the thermal behavior of IPNs and the evaluation of kinetic parameters. Degradation mechanism has also been investigated. Some of the mechanical properties viz. tensile strength, shore-A hardness, elongation at break, etc. are also reported. © 1993 John Wiley & Sons, Inc.     

Reinforcing effect of silica on the properties of styrene butadiene rubber–reclaim rubber blend system

Incorporation of silica into styrene butadiene rubber (SBR)–reclaim rubber (RR) blend system was carried out by sol–gel technique and conventional method. A well known silica coupling agent bis(3‐triethoxysilyl propyl) tetrasulfide was found to affect the curing characteristics and mechanical properties of SBR/RR vulcanizate. Here, the effect of RR on silica reinforcement was studied for different SBR/RR blend system. Silica incorporation by conventional mechanical mixing in absence of TESPT showed a much higher tensile properties than that of silica incorporated by the in situ sol–gel reaction of tetraethoxy silane both in presence and absence of TESPT. Studies of equilibrium swelling in a hydrocarbon solvent were also carried out. ATR study indicates that RR forms bond with silica particles due to the presence of active functional site on RR. The amount of silica incorporated by sol–gel reaction was determined through thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the silica filled SBR/RR vulcanizate. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 957–968, 2006     

Studies on the stability and kinetics of drug release of dexamethasone phosphate intercalated layered double hydroxides nanohybrids

We report the intercalation of dexamethasone sodium phosphate drug in Mg/Al layered double hydroxides (LDHs) through co-precipitation technique. The as-synthesized nanohybrid was characterized by XRD, FTIR and thermal analysis techniques, which reveal that the dexamethasone phosphate anions are accommodated within the brucite layers. The shifting in the stretching frequency of phosphate anion of the drug provides strong evidence that the drugs are bonded to LDHs through electrostatic force. The surface charge analysis suggested the possibility of charge manipulation in LDHs system by varying intercalated anions. In-vitro release study of as-synthesized nanohybrid particles suggests a significant reduction in release rate of dexamethasone phosphate anions from Mg/Al–Dexa LDHs and is due to confinement of drugs in the interlayer. The mechanism of drugs diffusion in nanohybrid is studied by using dissolution–diffusion kinetic model, which reveals that it is probably due to dissolution and intra-particle diffusion of anions in the physiological medium.     

One-dimensional ZnO nanostructures: fabrication, optoelectronic properties, and device applications

One-dimensional (1D) zinc oxide (ZnO) nanostructures have been extensively and intensively studied for several decades not only for their extraordinary chemical and physical properties, but also for their current and future different electronic and optoelectronic device applications. This review provides a brief overview of the progress of different synthesis methods and applications of 1D-ZnO nanostructures. Morphology of ZnO nanostructures grown by various methods and progress in the optical properties are briefly described. Using low-temperature photoluminescence (LTPL) study, detailed informations about the defect states and impurity of such nanostructures are reported. Improvement of field emission properties by modifying the edge of 1D-ZnO nanostructures is briefly discussed. Applications such as different sensors, field effect transistor, light-emitting diodes (LEDs), and photodetector are briefly reviewed. ZnO has large exciton binding energy (60 meV) and wide band gap (3.37 eV), which could lead to lasing action based on exciton recombination. As semiconductor devices are being aggressively scaled down, ZnO 1D nanostructures based resistive switching (RS) memory (resistance random access memory) is very attractive for nonvolatile memory applications. Switching properties and mechanisms of Ga-doped and undoped ZnO nanorods/NWs are briefly discussed. The present paper reviews the recent activities of the growth and applications of various 1D-ZnO nanostructures for sensor, LED, photodetector, laser, and RS memory devices.