Corrigendum to “Generalized periodicity and primitivity for words”

We correct a mistake in the paper “Generalized periodicity and primitivity for words” [4] and justify the existence of regular languages all of whose roots are not even context‐sensitive. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Mechanisms of a tumor marker,glutathione transferase P,expression during hepatocarcinogenesis of the rat

The molecular mechanism of any tumor marker expression may shed a light on the mechanism of the particular tumorigenesis. This idea in mind, we have been pursuing the mechanism of specific induction of the placental type glutathione transferase (GST-P) gene during hepatocarcinogenesis of the rat. Making use of advanced technologies of molecular biology including proteomic analysis, gene cloning and production of specific transgenic rats etc., we were able to identify the enhancer and the activator proteins responsible for this tumor marker expression. Negative regulatory regions and modulatory proteins were also found. The overview of this long range study and the future outlook of the problem will be discussed.     

The detection of glycosphingolipids in brain tissue sections by imaging mass spectrometry using gold nanoparticles

Glycosphingolipids (GSLs) are amphiphilic molecules consisting of a hydrophilic carbohydrate chain and a hydrophobic ceramide moiety. They appear to be involved primarily in biological processes such as cell proliferation, differentiation, and signaling. To investigate the mechanism of brain function in more detail, a more highly sensitive method that would reveal the GSL distribution in the brain is required. In this report, we describe a simple and efficient method for mapping the distribution and localization of GSLs present in mouse brain sections using nanoparticle-assisted laser desorption/ionization imaging mass spectrometry (IMS). We have developed and tested gold nanoparticles (AuNPs) as a new matrix to maximize the detection of GSLs. A matrix of AuNPs modified with alkylamine was used to detect various GSLs, such as minor molecular species of sulfatides and gangliosides, in mouse brain sections; these GSLs were hardly detected using 2,5-dihydroxybenzoic acid (DHB), which is the conventional matrix for GSLs. We achieved approximately 20 times more sensitive detection of GSLs using AuNPs compared to a DHB matrix. We believe that our new approach using AuNPs in IMS could lead to a new strategy for analyzing basic biological mechanisms and several diseases through the distribution of minor GSLs.     

Complexation behavior of mono- and disaccharides by the vinylbenzeneboronic acid–divinylbenzene copolymer resins packed in a high-performance liquid chromatographic column

Using an HPLC column packed with monodispersed vinylbenzeneboronic acid–divinylbenzene (V–D) copolymer resins, the elution behaviors of the mono- and disaccharides were studied under different pH mobile phases. The monodispersed V–D copolymer resins were prepared by the copolymerization of 4-vinylbenzeneboronic acid and divinylbenzene in the presence of template silica gel particles (particle size: 5 μm; pore size: 10 nm), followed by dissolution of the template silica gel using a NaOH solution. Similarly, styrene–divinylbenzene (S–D) copolymer resins as the control resins were also synthesized. The transmission electron micrographs of these polymer resins revealed a good monodispersity. The complexation behavior of the saccharides was evaluated by comparison of the peak area eluted through the V–D column for that through the S–D column. Four aldopentoses (d-ribose, d-arabinose, d-xylose, and d-lyxose) and four aldohexoses (d-glucose, d-mannose, d-galactose, and d-talose) were retained completely at pH 11.9. Especially, ribose and talose were totally retained even under acidic and neutral conditions. For the disaccharides, unlike sucrose and maltose, palatinose was completely retained in basic mobile phases.     

Separation and determination of quaternary ammonium compounds by high-performance liquid chromatography with a hydrophilic polymer column and conductometric detection

An HPLC method has been developed for separation and determination of long alkyl chain quaternary ammonium compounds. A column packed with a hydrophilic polymer packing, Shodex Asahipak GF-310 HQ, and a water–acetonitrile mixture containing 4,4′-bipyridyl and hydrochloric acid were used to depress hydrophobic adsorption of the quaternary ammonium compounds and increase the sensitivity of the conductometric detection with a micromembrane suppressor. Dodecyltrimethylammonium, cetyltrimethylammonium, tetradecyldimethylbenzylammonium and stearyltrimethylammonium ions can be completely separated from one another and quantified at 0.1 nmol level.     

Non-separable splines and numerical computation of evolution equations by the Galerkin methods

We construct new non-separable splines and we apply the spline sampling approximation to the computation of numerical solutions of evolution equations. The non-separable splines are basis functions which give a fine sampling approximation which enables us to compute numerical solutions by means of the method of lines combined with the Galerkin method. To demonstrate our approach we compute numerical solutions of the Burgers equation and the Kadomtsev–Petviashvili equation.     

Palladium-catalyzed Mizoroki-Heck reaction of allyl aryl ethers with aryl iodides using phosphine-free hydrazone ligands

Palladium-catalyzed Mizoroki-Heck reaction of allyl aryl ethers with aryl iodides gave aryl cinnamyl ethers using a catalytic amount of Pd(OAc)₂ in DMF at 50 °C with phosphine-free hydrazone as a ligand in good yields.