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In the biological and medical fields, sterilization using pulsed electric fields or discharges and electroporation have been studied actively in recent years. It is clear that a pulsed electric field has some sort of effect on an organism. At present, however, it is not sufficiently clear what effect occurs and how the mechanism of a pulsed electric field acts on the organism. The effects of pulsed electric fields on ribonucleic acid RNA expression in biological cells were studied with the objective of elucidating the bioelectric mechanism. A pulsed electric field was applied to Vibrio parahaemolyticus, a pathogenic bacteria, and the expression of RNAs, specifically thermostable direct hemolysin TDH, VP1680, and VP1699, which represent pathogenic agents, were analyzed using the polymerase chain reaction PCR method. The level of expression of VP1680 increased when a pulsed electric field was applied, and the effect was at a peak when the electric field strength was 14i¾?kV/cm. The electric field strength barely affected the expression of TDH and VP1699. It was found that the effects of the electric field were different among the RNAs. The expression level varied with time when expression was analyzed. These results suggest the possibility of selective control of gene expression by using pulsed electric fields and possible new applications such as the development of functional foods.

An excimer lamp constructed using a piezoelectric transformer (PT) has been developed and studied in our laboratory. The excimer lamp is based on the excitation of a dielectric barrier discharge (DBD) generated by a PT surface that induces a high voltage due to the piezoelectric effect. Spectroscopic measurement in the vacuum ultraviolet (VUV) region was performed for the excimer lamp filled with a He-Xe mixture and Ar. Emission spectra having a peak at 172 and 126 nm were found, which were respectively radiated from the and excimers returning to their ground states. A self-organization phenomenon (SOP) was also recognized in the He and Ar DBD. Static and time-resolved observations of the self-organized patterns were performed using single reflex and ICCD cameras, respectively. The formation of self-organized patterns in argon requires a small amount of air as an additive. In time-resolved observation, we found dark spots arrayed hexagonally in a weak emission on the PT surface, whose arrangement coincides well with that of bright hexagonal filaments. The dark spots are considered as the traces of accumulated charges on the dielectric electrode, which interrupt the hexagonally filamentary discharges. © 2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(10): 44–53, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10397

Catalytic synthesis of several D-ribofuranosides from 2,3,5-tri-O-benzyl-1-O-iodoacetyl-D-ribofuranose and trimethylsilylated nucleophiles such as 3β-cholestanyl trimethylsilyl ether and phenyl trimethylsilyl sulfide is efficiently promoted by tin(II) chloride under mild conditions. When allyltrimethylsilane, azidotrimethylsilane, etc., are used as nucleophiles, combined use of catalytic amounts of SnCl2 and SiCl4 also afforded the corresponding ribofuranosides in good yields.

Catalytic stereoselective synthesis of several ribonucleosides from 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl methyl carbonate and trimethylsilylated nucleoside bases is efficiently carried out by combined use of silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.

Catalytic aldol reactions of several aldehydes with trimethylsilyl enol ethers are effectively performed by combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate (AgClO4) or Lawesson’s reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) and silver perchlorate under mild conditions.

Catalytic stereoselective synthesis of 1,2-cis- or 1,2-trans-ribofuranosides from 1-O-iodoacetylribofuranose and alkyl trimethylsilyl ethers is efficiently promoted by combined use of silver salts and lithium perchlorate or diphenyltin sulfide (Ph2Sn=S) under mild conditions.

Catalytic synthesis of β-D-ribofuranosides from C-1 free ribofuranose, 2,3,5-tri-O-benzyl-D-ribofuranose, and alcohols is efficiently performed by combined use of silver salts and Lawesson’s reagent, [2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide], or silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.

Several β-D-ribonucleosides are stereoselectively synthesized in high yields from methyl 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl carbonate and trimethylsilylated nucleoside bases such as pertrimethylsilylated uracil and adenine under mild conditions by using a catalytic amount of tin(II) chloride, a weak Lewis acid.

Several β-d-ribonucleosides were synthesized in high yields under mild conditions by N-glycosylations of methyl 2,3,5-tri-O-benzoyl-β-d-ribofuranosyl carbonate (1) with trimethylsilylated nucleoside bases in acetonitrile using a catalytic amount of metal iodide such as SnI2, SbI3 or TeI4. A deprotection of N6 -benzoyl group of coupling product took place to a considerable extent when N6 -benzoyl-N6 , N9 -bis(trimethylsilyl)adenine was employed as a nucleoside base using SnI2 or SnCI2 as a catalyst while it was minimized when SbI3 or TeI4 was used. Further, the N-glycosylation of 1 with 7-trimethylsilyltheophylline in the presence of a catalytic amount of metal iodide was more effectively achieved in nitrile solvents other than acetonitrile. #This paper is dedicated to Dr. Yoshihisa Mizuno on the occasion of his 75th birthday.