Development of dynamic compartment model for prediction of behavior of radioiodine in rice paddy field

For the assessment of a public impact caused by radionuclides released from nuclear facilities, a dynamic compartment model was developed for prediction of behavior of radioiodine in air, paddy field and rice plant system. The transfer coefficients among compartments were determined by some experimental data and assumptions for each chemical form of iodine. A verification of the model was carried out by some case studies.     

Adsorption Isotherm of Water Vapor and Its Large Hysteresis on Highly Ordered Mesoporous Silica

The first and second adsorption–desorption isotherms of water vapor on a new mesoporous material derived from kanemite have been measured. The isotherms show unusual type V isotherms and large hysteresis. The type V isotherms, which have never been observed for the other adsorbates, suggest that the mesoporous material has a hydrophobic surface, although the hydrophobicity decreased after treatment with water vapor because of rehydration of the surface. The significantly large hysteresis could be explained by the difference in contact angle between adsorption and desorption.     

Combinatorial synthesis of MUC1 glycopeptides: polymer blotting facilitates chemical and enzymatic synthesis of highly complicated mucin glycopeptides

The chemoselective polymer blotting method allows for rapid and efficient synthesis of glycopeptides based on a "catch and release" strategy between solid-phase and water-soluble polymer supports. We have developed a heterobifunctional linker sensitive to glutamic acid specific protease (BLase). The general procedure consists of five steps, namely (i) the solid-phase synthesis of glycopeptide containing BLase sensitive linker, (ii) subsequent deprotections and the release of the glycopeptide from the resin, (iii) chemoselective blotting of the glycopeptide intermediates in the presence of water-soluble polymers with oxylamino functional groups, (iv) sugar elongations using glycosyltransferases, and (v) the release of target glycopeptides from the polymer platform by selective BLase promoted hydrolysis. The combined use of the solid-phase chemical syntheses of peptides and the enzymatic syntheses of carbohydrates on water-soluble polymers would greatly contribute to the production of complicated glycopeptide libraries, thereby enhancing applicative research. We report here a high-throughput synthetic system for the various types of MUC1 glycopeptides exhibiting a variety of sugar moieties. It is our belief that this concept will become part of the entrenched repertoire for the synthesis of biologically important glycopeptides on the basis of glycosyltransferase reactions in automated and combinatorial syntheses.     

Functional monomers and polymers. LXXI. Conformation and interaction studies of poly-L-lysine derivatives with pendant nucleic acid bases

Copolymers of L -lysine and L -lysine derivatives which contained nucleic acid bases substituted on the N^ε position were synthesized by grafting nucleic acid derivatives onto poly-L -lysine. The conformation and interaction of these copolymers in solution were studied by using spectroscopic measurements. They existed in helical conformation at neutral pH values, and the polymer complex formation among them was examined by ultraviolet (UV) measurements in organic solvents. A decrease in the nucleic acid base content of the copolymers resulted in a decrease in helical structures and also in interactions with the polymer-containing complementary bases.     

Activity of artificial mutant variants of human growth hormone deficient in a disulfide bond between Cys53 and Cys165

In order to understand the role of Cys53 and Cys165 of human growth hormone (hGH) in receptor-binding and biological activity, artificial mutant variants of hGH were prepared in Escherichia coli by in vitro mutagenesis. Variants of hGH were constructed by replacement of Cys165 with Ala ([Ala165]hGH) or Ser ([Ser165]hGH), by replacement of Cys53 with Ala ([Ala53]hGH), by replacement of Cys53 and Cys165 with Ala ([Ala53, Ala165]hGH), or by replacement of Cys53 with Ala and Cys165 with Ser ([Ala53,Ser165]hGH). All of the variants constructed as well as reduced hGH exhibited less biological activity than that of intact hGH, and the decreases in biological activity were almost equal, as measured by a sensitive biological assay for growth hormone: adipose conversion assay using 3T3-F442A cells. These variants also showed less receptor-binding activity than that of intact hGH. These results suggest that it is possible neither the residue Cys53 nor Cys165 is directly involved in the receptor binding, and that the disulfide bridge between Cys53 and Cys165 in hGH may not always be crucial for the biological activity, though necessary to express full hGH activity.     

The reaction of trialkylvinylborates with aldehydes as applied to syntheses of 1,3-alkanediols, 1-chloro-3-heptanol and a cyclopropane derivative

Treatment of R'CHO with Li[R₃BCHCH₂] gives an adduct which is believed to be R₂BCHR-CH₂-CH(OLi)R' (2) or its borate form (3). Oxidation of the adducts with alkaline hydrogen peroxide gives ca. 1:1 mixture of diastereomeric 1,3-alkanediols in good yields. On the other hand, the reaction of BrMg[R₃BCHCH₂] with R'CHO affords less satisfactory results. Successive treatment of 2 (R = n-Bu, R' = H) with PCl₅ and alkaline H₂O₂ gives HOCHBu-CH₂-CH₂Cl (6). Treatment of Et₂BCHEt-CH₂-CHCl-Ph with NaOH aq produces l-ethyl-2-phenylcyclopropane 7.     

Synthesis of optically active forms of seudenol,the pheromone of douglas fir beetle

(R)-(+)-Seudenol (3-methylcyclohex-2-en-1-ol) and its antipode were synthesized from optically active forms of 3-iodocyclohex-2-en-1-ol by treatment with Me₂CuLi. Their absolute configurations were determined by converting (+)-3-iodocyclohex-2-en-1-ol to the known (R)-(+)-cyclohex-2-en-1-ol.     

Linear free energy relationships for carbon-13 NMR chemical shifts of substituted benzoic acids1

In order to examine ¹³C-SCS of substituted benzoic acids, chemical shifts of the acid form (I) and the dissociated form (II) have been obtained separately. Single substituent parameters, σ⁰ or σ⁺ are correlated with the shifts for the carboxyl (δ_co) or ipso carbons (δ_ipso), respectively. Among the available five equations which are developed for the analysis with dual (or divided) substituent parameters (DSP), the Swain-Lupton equation (eqn 3) and the Taft-Swain-Lupton equation (eqn 4) give much better correlations, not only for δ_co and δ_ipso but also for the results for ring carbons (C(2), C(5), C(6)), except for those attached to or neighboured by substituents. It is concluded that the SCS of aromatic compounds are best analyzed with substituent parameters derived from reactions or equilibria on the basis of linear free energy relationships.     

Capacitance-conductance detector for high-pressure liquid chromatography. Application to alkaloids and fatty acids

Summary A new type of detector for high-pressure liquid chromatography has been designed. This detector is equipped with a RC resonance circuit, and is similar to the capacitance detector previously reported. It is operated as a capacitance detector with nonpolar eluents; while with polar solvents, it behaves as a conductance detector. Electrolytes such as salts, acids and bases are sensitively detected. The detector was successfully used for the detection of fatty acids and alkaloids.

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Zusammenfassung Ein neuartiger Detektor für die Hochdruck-Flüssigchromatographie wurde entwickelt. Dieser ist mit einem Resonanzstromkreis ausgestattet und ähnelt dem kürzlich beschriebenen Kapazitanz-Detektor. Als solcher funktioniert er mit nichtpolaren Eluenten, während er sich mit polaren Lösungsmitteln wie ein Leitfähigkeitsdetektor verhält. Salze, Säuren und Basen werden empfindlich nachgewiesen. Das Gerät wurde zum Nachweis von Fettsäuren und Alkaloiden verwendet.