Interaction of kunjin virus with octyl-D-glucoside extracted Vero cell plasma membrane

Initial experiments using whole cells have shown that there were specific and saturable interactions between kunjin (KUN) virus and receptor molecules on the Vero cell surfaces. Solubilisation of Vero cell plasma membranes with octyl-D-glucoside (OG) yielded an extract which also interacted specifically with KUN virus. This was proven using electron microscopy. When the virus-OG-extract complex was exposed onto Vero cell monolayers, no KUN virus was observed to enter into the whole cells. This would imply that there was virus-receptor interaction with the OG-extract leaving no free virus to attach to the whole cells. The attachment kinetics of KUN virus was studied further using the Scatchard analysis which indicated the involvement of more than one interactive macromolecule in the attachment event.     

Texture and microstructure evolution during tempering of gamma-massive phase in a TiAl-based alloy

This work focuses on the mechanisms of microstructure and crystallographic texture evolution during gamma-massive transformation and subsequent tempering treatments, in the case of the Ti–48Al–2Nb–2Cr (at%) TiAl-based alloy. A complete massive structure is obtained by ice-water quenching. The temperature range for the destabilization of this massive structure is estimated from DSC measurement. Then, tempering is performed in both α₂–γ and α–γ phase fields. Microstructure evolution is studied by transmission and scanning electron microscopy observation of samples from different stages of the heat treatments. Isotropic samples resulting from a powder-metallurgy route are used for this purpose. Then, working on the samples from investment casting, the reduction of solidification texture through massive then tempering treatments is analyzed at the light of the mechanisms of microstructure evolution identified previously.     

Schottky barrier diodes for millimeter wave detection in a foundry CMOS process

CoSi/sub 2/-Si Schottky barrier diodes on an n-well and on a p-well/substrate are fabricated without a guard ring in a 130-nm foundry CMOS process. The nand p-type diodes with an area of 16/spl times/0.32/spl times/0.32 /spl mu/m/sup 2/ achieve cutoff frequencies of /spl sim/1.5 and /spl sim/1.2 THz at 0-V bias, respectively. These are the highest cutoff frequencies for Schottky diodes fabricated in foundry silicon processes. The leakage currents at 1.0-V reverse bias vary between 0.4 to 10 nA for the n-type diodes. The break down voltage for these diodes is around 15 V. It should be possible to use these in millimeter wave and far infrared detection.     

Cellular Scent of Influenza Virus Infection.

Volatile organic compounds (VOCs) emanating from humans have the potential to revolutionize non‐invasive diagnostics. Yet, little is known about how these compounds are generated by complex biological systems, and even less is known about how these compounds are reflective of a particular physiological state. In this proof‐of‐concept study, we examined VOCs produced directly at the cellular level from B lymphoblastoid cells upon infection with three live influenza virus subtypes: H9N2 (avian), H6N2 (avian), and H1N1 (human). Using a single cell line helped to alleviate some of the complexity and variability when studying VOC production by an entire organism, and it allowed us to discern marked differences in VOC production upon infection of the cells. The patterns of VOCs produced in response to infection were unique for each virus subtype, while several other non‐specific VOCs were produced after infections with all three strains. Also, there was a specific time course of VOC release post infection. Among emitted VOCs, production of esters and other oxygenated compounds was particularly notable, and these may be attributed to increased oxidative stress resulting from infection. Elucidating VOC signatures that result from the host cells response to infection may yield an avenue for non‐invasive diagnostics and therapy of influenza and other viral infections.     

Silver Stars: Silver–Polymer Composite Stars: Synthesis and Applications (Adv. Funct. Mater. 9/2011)

Colloidal “silver stars” were synthesized upon poly(lactic‐co‐glycolic) acid nanosphere templates via a facile two‐step silver reduction method. Myriad dendrimer‐like Ag star morphologies were synthesized by varying the amount of poly(vinyl alcohol) and trisodium citrate used during silver reduction. Scanning electron microscopy studies revealed that star‐shaped silver–polymer composites possessing nanoscopic, fractal morphologies with diameters ranging from 500 nm to 7 μm were produced. These composites have broad applications from antibacterial agents to catalysis; two such applications were tested here. Surface‐enhanced Raman spectroscopy (SERS) studies showed multiple hot spots of SERS activity within a single star. Electrochemical catalysis experiments demonstrated the feasibility of using the silver stars instead of platinum for the oxygen reduction reaction in alkaline fuel cells.     

Identification of adenine binding domain peptides of the NADP+ active site within porcine heart NADP(+)-dependent isocitrate dehydrogenase

Photoaffinity labeling with [2'-32P]2N3NADP+ and [32P]2N3NAD+ was used to identify two overlapping tryptic and chymotryptic generated peptides within the adenine binding domain of NADP(+)-dependent isocitrate dehydrogenase (IDH). Photolysis was required for insertion of radiolabel, and prior photolysis of photoprobes before addition of IDH prevented insertion. Photoincorportion of 2N3NAD+ inhibited the enzymatic activity of IDH. Photolabeling of IDH with both [32P]2N3NAD+ and [2'-32P]2N3-NADP+ showed saturation effects with apparent Kds of 20 and 14 microM (+/-12%), respectively. The efficiency of photoincorporation at saturation of binding sites was determined to be about 50%. Also, photolabeling was observed with [32P]8N3ATP and [32P]2N3ATP but with saturation effects observed at lower affinity. With all radiolabeled probes reduction of photoinsertion was effected best by the addition of NADP+ followed by NAD+ and then ATP, indicating that photoinsertion with all the probes was within the NADP+ binding site. Isolation of [32P]2N3NAD+ and [2'-32P]2N3NADP+ photolabeled peptides by use of immobilized boronate and immobilized Al3+ chromatography, respectively, followed by HPLC purification resulted in the identification of overlapping peptides corresponding to Ile244-Arg249 and Leu121-Arg133 (tryptic fragments) and Lys243-His248 and Leu121-His135 (chymotryptic fragments). Trp125 and Trp245 were identified as the sites of photoinsertion based on these residues not being detectable on sequencing, the lack of chymotryptic cleavage at these residues, and the decreased rate of trypsin digestion at nearby Lys243 and Lys127. Sequence analysis of [32P]8N3ATP and [32P]2N3ATP photolabeled peptides gave essentially the same peptide regions being photolabeled but at much lower efficiency, indicating that the effects of ATP on IDH activity are dependent on competition for the same site.     

Optimum design of stiffened cylindrical panels with constraint on the frequency in the presence of initial stresses

This paper presents the optimum design of stiffened cylindrical panels with weight as the objective function and constraints on the frequencies in the presence of initial stresses, using unconstrained minimization techniques of non-linear mathematical programming problem. The interaction between the buckling constraints and the frequency constraints in the presence of initial stresses are included in the formulation. Loss of load carrying capacity due to imperfection and due to suddenly applied loads are included in the buckling analyses. Results for cylindrical shell are obtained by setting the panel angle to 360 degrees. The relationship between the weight of the cylinder and the panel (a segment of the cylinder) is examined.     

A Microprocessor Based Measuring Instrument for Rapid Testing of Transformer Core Material

Precise knowledge of the characteristics of core material Is essential for the design of electromagnetic devices I Ike dynamos, I nstrument transformers and relays. Conventional measurement of the core characteristics Is a tedious process as it Involves collection of voluminous data and corrections thereto. An instrument using linear compensating networks and exploiting the processing capabilities of the popular microprocessor is developed for the measurement of core characteristics such as specific iron loss and the dynamic B-H curve. The necessary corrections are Incorporated In the software so that the end result can be straightaway used in design.     

Experimental studies on the aetiology of acute scorpion pancreatitis

This study examined the action of the venom of the scorpion Tityus trintatis on the pancreas and gastrointestinal tract in anaesthetized dogs, on the isolated extracorporeal haemoperfused canine pancreas and on the isolated canine sphincter of Oddi. The venom induces exocrine secretion in both the isolated and intact pancreas and causes contraction of the isolated sphincter of Oddi. These results are discussed in relation to the pathogenesis of acute scorpion pancreatitis and possibly of some other forms of acute pancreatitis.     

Stability of tapered cantilever columns subjected to follower forces

Accurate estimates of critical loads of tapered cantilever columns with fixed or spring hinged ends subjected to follower forces are obtained in this paper. A Galerkin finite element method is used to solve the governing differential equation with variable coefficients. The effect of the stiffness of the spring hinge on the critical load is also studied.