Synthesis of silicone–acrylic resins and their applications to superweatherable coatings

Silicone–acrylic resins were synthesized to prepare superweatherable paints for building materials. The raw materials used were n‐butyl acrylate, methyl methacrylate, and n‐butyl methacrylate as acrylic monomers and 3‐methacryloxypropyltrimethoxysilane (MPTS) as a silicone monomer reactive with the acrylic monomers. Acrylic copolymers were synthesized such that their glass‐transition temperatures were adjusted to 30°C and their MPTS contents were varied to 10, 20, and 30 wt %. As the content of silicone and MPTS increased, average molecular weight and viscosity increased, and thermal stability at high temperatures improved. When we tested the properties of coatings by blending the synthesized silicone–acrylic resins with a white pigment, adhesion was superior with various substrates, and their properties were suitable on the whole. Weatherability was tested by an outdoor exposure test with a weather‐ometer and an accelerated weathering tester, and their results showed that silicone–acrylic resin composed of 30 wt % MPTS was a superweatherable coating. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1614–1623, 2001     

Effect of Proline and Glutamine on the Functional Properties of Wheat Dough in Winter Wheat Varieties

ABSTRACT: Combinations of proline and glutamine significantly increased the functional properties of soft wheat that were unseen when added individually. To hard wheat, proline contributed more positively than glutamine on most dough and bread properties, which is different from the observations with soft wheat. Addition of glutamine to hard wheat increased the amount of gluten and glutenin after mixing, whereas proline hinders gluten formation despite the increase in glutenin. The ability of proline and glutamine to modify the functional properties of dough and bread appears to be interdependent. Addition of either proline or glutamine appears to have a protective effect on the retention of the other amino acid during breadmaking.     

A new approach to the analysis of tannin concentration using a microelectronic biosensor

Wine tannins are essential to the astringency and color stabilization of red wine through the formation of tannin conjugates. It is important to determine the concentration of tannins during wine aging and fermentation. The aim of this study was to establish a new method that allows for real-time analysis of tannin content in wine and eliminates inconvenient processes, such as calibrations and/or enzyme reactions. The Folin-Ciocalteau spectrophotometry (FCS) was used a positive control and compared it with new microelectrode biosensor cyclic voltammetry (MBCV) method. The new approach was established that not only allows for real-time tannin detection but is also economical and does not require the use of a specific enzyme. The results are reproducible and provide a precise measurement of tannin content.     

Blending of different domestic grape wines using mixture design and optimization technique

Objectives of this study were to make a Muscat Bailey A (MBA) wine from grapes raised in Yongdong, Korea using various manufacturing methods and to blend it with Gerbong and Campbell wines using optimization technique. Effects of fermentation temperatures and of American and French toasted oak chips were determined. The highest sensory score was achieved from without the bacteria at 11°C and with bacteria at 17°C, respectively. Higher preference value was obtained from the heavy toasted, and French oak chip. Three kinds of red wines made from 3 different varieties were mixed at the various ratio and optimized. As a result of numerical and graphical optimization, the ratio of 11.1 (Gerbong wine): 48.9 (Campbell wine): 40.0 (MBA wine) produced the best sensory score. This study was performed to improve the quality of MBA wine, and an optimum blending formulation for better quality wine was obtained.     

30-nm InAs Pseudomorphic HEMTs on an InP Substrate With a Current-Gain Cutoff Frequency of 628 GHz

We report on InAs pseudomorphic high-electron mobility transistors (PHEMTs) on an InP substrate with record cutoff frequency characteristics. This result was achieved by paying attention to minimizing resistive and capacitive parasitics and improving short-channel effects, which play a key role in high-frequency response. Toward this, the device design features a very thin channel and is fabricated through a three-step recess process that yields a scaled-down barrier thickness. A 30-nm InAs PHEMT with t _ins = 4 nm and t _ch = 10 nm exhibits excellent g _m, _max of 1.62 S/mm, f _T of 628 GHz, and f _max of 331 GHz at V _DS = 0.6 V . To the knowledge of the authors, the obtained f _T is the highest ever reported in any FET on any material system. In addition, a 50-nm device shows the best combination of f _T= 557 GHz and f _max = 718 GHz of any transistor technology.     

The yiaE gene, located at 80.1 minutes on the Escherichia coli chromosome, encodes a 2-ketoaldonate reductase

An open reading frame located in the bisC-cspA intergenic region, or at 80.1 min on the Escherichia coli chromosome, encodes a hypothetical 2-hydroxyacid dehydrogenase, which was identified as a result of the E. coli Genome Sequencing Project. We report here that the product of the gene (yiaE) is a 2-ketoaldonate reductase (2KR). The gene was cloned and expressed with a C-terminal His tag in E. coli, and the protein was purified by metal-chelate affinity chromatography. The determination of the NH2-terminal amino acid sequence of the protein defined the translational start site of this gene. The enzyme was found to be a 2KR catalyzing the reduction of 2, 5-diketo-D-gluconate to 5-keto-D-gluconate, 2-keto-D-gluconate (2KDG) to D-gluconate, 2-keto-L-gulonate to L-idonate. The reductase was optimally active at pH 7.5, with NADPH as a preferred electron donor. The deduced amino acid sequence showed 69.4% identity with that of 2KR from Erwinia herbicola. Disruption of this gene on the chromosome resulted in the loss of 2KR activity in E. coli. E. coli W3110 was found to grow on 2KDG, whereas the mutant deficient in 2KR activity was unable to grow on 2KDG as the carbon source, suggesting that 2KR is responsible for the catabolism of 2KDG in E. coli and the diminishment of produced 2KDG from D-gluconate in the cultivation of E. coli harboring a cloned gluconate dehydrogenase gene.     

DNA damage by gliotoxin from Aspergillus fumigatus. An occupational and environmental propagule: adduct detection as measured by 32P DNA radiolabelling and two-dimensional thin-layer chromatography

Gliotoxin is produced by the fungus Aspergillus fumigatus. Aspergillus is widespread in the environment and this ubiquitous nature results in disease and co-carcinogenesis to be distributed world-wide. Gliotoxin contains an epipolythiodioxopiperazine (ETP) ring that is believed to be involved in redox reactions. The reactive oxygen species produced interact with DNA to form hydroxylated and other altered DNA products. To measure DNA adduct formation, we used 32P radiolabelling and, after enzymatic DNA digestion, separated adducts in two dimensions using thin-layer chromatography (2D-TLC), with ultimate autoradiography and densitometry. HeLa DNA was incubated with 0.1 mmol l-1 and 0.3 mmol l-1 of gliotoxin (and necessary redox agents) for 1 and 20 h. We found an increase in 6-hydro-5,6-dihydroxythymidine (thymine glycol) monophosphate [d(TG)MP] from 0.0% to 30.4%, an increase in 8-hydroxy-2'-deoxyguanidine monophosphate [8(OH)dGMP] from 0.0% to 4.2%, an increase in deoxynucleotide diphosphate (dNDP) from zero adducts to six DNA adducts, as well as an increase of other as yet unidentified adducts. Also, time exposure may have a greater effect than concentration based on a 20-h incubation with 0.3 mmol l-1 gliotoxin that completely obliterates the pyrimidines deoxythymidine 3'-monophosphate (dTMP) and deoxycytidine 3'-monophosphate (dCMP).     

Effects of Oxygen Supply Modes on the Production of Human Growth Hormone in Different Scale Bioreactors

Recombinant Escherichia coli has been studied as a main host for recombinant protein productions, but it is still difficult to cultivate E. coli in a large industrial‐scale process due to the oxygen supply limitation. In this study, E. coli BL(21) harboring a new constructed plasmid (pEHUb‐hGH) was used for producing recombinant human growth hormone (r‐hGH) in 5‐L and 30‐L scale fermentors by supplying air and high purity oxygen, respectively, where the high purity oxygen was produced from a vacuum pressure swing adsorption (PSA). The impact of oxygen supply modes, i.e., air and high purity oxygen, on cell growth and r‐hGH production was investigated in different scale fermentors. In the case of high purity oxygen supply, the final cell density and r‐hGH concentrations were 63.0 and 4.8 g/L in the 5‐L fermentor, 51.6 and 4.0 g/L in the 30‐L fermentor, respectively. In addition, the productivity of r‐hGH was doubled in the 5‐L fermentor, and increased 4‐fold in the 30‐L fermentor, compared to the results obtained in the case of the air supply. The supply of high purity oxygen eliminated the oxygen limitation and acetate formation effectively, and apparently, did not affect the degradation of r‐hGH. This shows that the recombinant E. coli cultivation with high purity oxygen produced from PSA may provide an effective method for large‐scale industrial production of recombinant proteins.     

Non-core based shared tree architecture for IP multicasting

The core-based tree (CBT) has three main limitations. The selection of the core node is difficult and the traffic is concentrated near the core router. Also the CBT does not consider an optimisation of network resource utilisation. In the proposed non-core based tree (NCBT), an on-tree node is assigned to each incoming member for multicasting such that the maximum end-to-end delay and the tree costs are jointly minimised.     

Generation of a novel poliovirus with a requirement of hepatitis C virus protease NS3 activity

Hepatitis C virus (HCV) is the major etiologic agent of non-A, non-B hepatitis. One of the difficulties in developing anti-HCV drugs is the lack of an efficient HCV cultivation system. We have generated an artificial surrogate virus suitable for testing the antiviral effects of drugs affecting HCV protease NS3, an enzyme believed to be essential for HCV proliferation. The surrogate virus genome is composed of most of the poliovirus genome and HCV protease NS3 and an NS3-specific cleavage site. The activity of HCV protease NS3 is required for proliferation of this chimeric virus. The antiviral efficacy of HCV protease inhibitors can, therefore, be evaluated by examining the effects of the drugs on the surrogate virus proliferation.