Tetraphenylporphyrin Enters the Ring: First Example of a Complex between Highly Bulky Porphyrins and a Protein**

Tetraphenylporphyrin (TPP) is a symmetrically substituted synthetic porphyrin whose properties can be readily modified, providing it with significant advantages over naturally occurring porphyrins. Herein, we report the first example of a stable complex between a native biomolecule, the haemoprotein HasA, and TPP as well as its derivatives. The X-ray crystal structures of nine different HasA-TPP complexes were solved at high resolutions. HasA capturing TPP derivatives was also demonstrated to inhibit growth of the opportunistic pathogen Pseudomonas aeruginosa. Mutant variants of HasA binding FeTPP were shown to possess a different mode of coordination, permitting the cyclopropanation of styrene.     

Susceptibility of Various Starch Granules to Amylases as Seen by Scanning Electron Microscope

Starch granules were observed by a scanning electron microscope in order to provide information concerning the types and extent of damage of the surface and internal structure of starch granules attacked by amylases. Granules resistant to the action of amylases, namely, potato, yamanoimo, and high-amylose maize starches showed shapes and surfaces similar to the intact granules after the action of either Rhizopus glucoamylase or crystalline bacterial α-amylase. Granules susceptible to amylases, namely, normal, waxy, soft starch, and soft starch opaque-2 maize starches showed numerous pin holes on the surface layer and pores penetrated into the inner layers of the granules during the attack with amylases. In the case of α-amylolysis, it is apparent that once the enzyme has penetrated into the inner layers of a granule, the layers are more readily attacked than the peripheral layers.     

Output power leveling of wind turbine generator by pitch angle control using H∞ control

Effective utilization of renewable energies such as wind energy is expected instead of the fossil fuels. Wind energy is not constant and windmill output is proportional to the cube of wind speed, which causes fluctuating power of wind turbine generator (WTG). In order to reduce the fluctuating power of WTG, this paper presents an output power leveling technique of WTG by pitch angle control using H_∞ control, and the control input of WTG linear model is separated from the disturbance. The simulation results using actual detailed model for WTG show the effectiveness of the proposed method. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(4): 17–24, 2008; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20657     

Preparation,morphology, and physical properties of transparent PSt hybrid materials containing silicone macromonomer

The aim of this study was to prepare transparent polystyrene (PSt) hybrid materials containing silicone macromonomer. Silicone urethane methacrylate (SiUMA) was synthesized by the reaction between the hydroxyl end groups of a silicone macromonomer and the isocyanate group of 2‐methacryloyloxyethyl isocyanate (MOI), and copolymers with different weight proportions were prepared by copolymerization of styrene (St), SiUMA and ethyleneglycol dimethacrylate (EGDMA). Though the prepared P(St‐co‐SiUMA) copolymers which had not introduced EGDMA were opaque, the prepared P(St‐co‐SiUMA‐co‐EGDMA) copolymers were transparent, similarly to pure PSt. DSC and ¹H‐NMR measurements were carried out to investigate the factors in this transparency in detail. From these measurement results, it was confirmed that the reactivity of the copolymerization had a significant influence on the transparency of the product. In addition, the contact angle of P(St‐co‐SiUMA‐co‐EGDMA) with 10 wt % SiUMA was greater than 90°, which was a 10° improvement compared to pure PSt. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Comparative Susceptibility to Amylases of Starch Granules of Several Single Endosperm Mutants and Their Double-Mutant Combinations with Opaque-2 in Four Inbred Lines of Maize

The relative susceptibility of starch granules of single mutants and double-mutant combinations of maize and their normal counterparts to Rhizopus glucoamylase and pancreatin was compared and the relative degradation of starch granules followed by scanning electron microscopy. Starch granules of distinct endosperm mutants were resistant to the action of amylases whilst others showed pin holes on the surface and pores into the inner layers. Starch granules of the sugary, brittle, shrunken, and waxy mutants tended to be digested faster than those of their normal counterparts. The opaque-2 mutant which improves nutritional quality of endosperm proteins did not change the susceptibility of starch granules to degradation by amylases.     

Structural and Physicochemical Properties of Endosperm Starches Possessing Different Alleles at the Amylose-extender and Waxy Locus in Maize (Zea mays L.)

The structure and some physicochemical properties of endosperm starches from seven amylose-extender (ae) and two waxy (wx) alleles of maize (Zea mays L.) were studied. Starches prepared from mature kernels of six ae mutants, Oh43 inbred line ae (standard ae), ae-RWB-2 and ae-RWB-3, and W23 × L317 hybrid line ae-PP, ae-Bol 561 and ae-emll, were uniquely ae type, as was concluded from B type X-ray diffractograms; high gelatinization temperatures determined by differential scanning calorimetry (DSC); with poor starch-granule digestibility to amylase; high amylose (37—45 %) and high intermediate fraction (13—18 %) contents; and low ratios (1.0—1.2) of long α-1,4-chains to short α-1,4-chains of amylopectin determined by gel permeation chromatography (GPC) of isoamylase-debranched starches. The results also indicated that different ae alleles had different effects on the amylose content of endosperm starches. Mature kernels of Oh43 ae-RWB-1 mutant showed tarnished and translucent phenotype characteristics of the ae genotype but contained endosperm starch with 21—22 % of amylose which was lower than that of the Oh43 normal counterpart. Both wx-B and wx-C (standard wx) genes have similar effect on structure and physicochemical properties of waxy starches of A632, B37, C105, Oh43, and W64A inbred lines.     

A Sol-Gel Derived Organic/Inorganic Hybrid Membrane for Intermediate Temperature PEFC

Intermediate temperature operation of polymer electrolyte fuel cells has been pointed out to be a promising option to overcome most of the technological problems of the current PEM system and new classes of electrolyte membrane have been investigated elsewhere. Proton conducting organic/inorganic nano-hybrid polymer electrolyte membranes have been synthesized in the present work. The membranes were synthesized by bridging temperature tolerant polyether polymers such as PEO or PTMO to inorganic silicate moieties to form organic/inorganic hybrid macromolecules. The hybrid membranes become proton conducting polymer electrolytes by doping with heteropolyacids such as 12-phosphotungstic acid (PWA). The conducting properties of the membrane were studied by modifying the polyether structure, molecular weight, PWA concentration, water content, and also various processing conditions. The membranes are flexible and thermally stable due to the temperature tolerant inorganic frameworks of the macromolecules. The proton conductivity of the membranes is in a range from 10^–3–10^–2 S/cm up to 140 °C under controlled humidity.     

Some Structural Characteristics of Starches of Maize Having a Specific Genetic Background

Distribution of starch components of maize (Zea mays L.) and their properties were investigated by gel filtration after debranching and by exhaustive hydrolysis of starch-granules with glucoamylase. Based on the results, relationship between genotypes and properties of starch components were discussed. The sugary-1 (su₁), sugary-2 (su₂), and dull (du) mutants produced high amylose maize, while amylopectin of su₂ was normal type and those of su₁ and du were novel type. In the double-mutant combinations, the waxy (wx) gene decreased amylose content. Starches of du su₁ or du su₂ possessed greatest amount of amylose among starches examined. Contents of amylose, intermediate fraction (Fr.) and longer branches of amylopectin increased in most cases when the amylose-extender (ae) gene was introduced. Starches of ae possessed longer average chain-lengths of amylopectin than that of normal. In ae du starches, however, elongation of the amylopectin chain and increase of the intermediate Fr. did not occur. Exhaustive degradation of starch-granules by glucoamylase showed that ae starches were more resistant to amylase.