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Shigenobu Hayashi

Publications and source records attributed to Shigenobu Hayashi.

9 recordsLinked to original sources
PubMed2006

Dynamics of p-nitroaniline molecules in micoporous aluminophosphate AlPO4-5 studied by solid-state NMR.

Dynamics of deuterated p-nitroaniline (pNA-d) molecules in the micropores of AlPO4-5 has been investigated by means of solid-state NMR. The adsorbed amounts of pNA-d were 5.0 and 10.1 mass % of the total mass. We have measured 13C magic-angle-spinning (MAS) and 2H NMR spectra of the guest molecules and 31P and 27Al MAS NMR spectra of the host framework. The pNA-d molecules distribute rather inhomogeneously in the channel, and do not coordinate to Al strongly like H2O. The intermolecular hydrogen bonds are formed between a part of the guest molecules only when the loading level is high. The 2H NMR spectra are successfully analyzed, elucidating the orientation and the motion of the guest molecules. The molecular axis of pNA-d is inclined to the channel axis, and the molecular plane is perpendicular to the inner wall. The guest molecule jumps among 12 sites or 12 orientations. This motion is faster in the sample of 5.0 mass % than in the sample of 10.1 mass %, suggesting that the guest-guest interaction hinders the motion. The mean residence times of the molecules are estimated from the analysis of the 2H NMR spectra, which are affected by the size of the nanospace as well as the property of the adsorbed site.

Aluminum Compounds↗
PubMed2006

Gene expression in the brain from fluoxetine-injected mouse using DNA microarray.

Previously we have examined the effects of phencyclidine and clozapine upon the gene expression in the mouse brain. Recently, fluoxetine (Prozac) has been introduced for the therapeutic purpose as an antidepressant drug. Miledi et al. reported blockage of mouse muscle and neuronal nicotinic acetylcholine receptor by various concentrations of fluoxetine. Furthermore, Kobayashi et al. discovered that fluoxetine inhibits G protein activated inwardly rectifying G protein activated K(+) (GIRK) channels using Xenopus oocyte expression assay. From these experiments, we considered that it might be interesting to study the effects of fluoxetine on the gene expression in the mouse brain. After we have injected fluoxetine once a day into mouse for 20 days, we sacrificed mouse by decapitation and extracted RNA from mouse cerebral cortex. We used DNA microarray method for examining the gene expression in the brain. We found the downregulation of many spot signals in the fluoxetine-treated mouse, for example cholecystockinin and prostaglandin D2 synthase.

Animals↗
PubMed2005

Green chemistry: biodiesel made with sugar catalyst.

The production of diesel from vegetable oil calls for an efficient solid catalyst to make the process fully ecologically friendly. Here we describe the preparation of such a catalyst from common, inexpensive sugars. This high-performance catalyst, which consists of stable sulphonated amorphous carbon, is recyclable and its activity markedly exceeds that of other solid acid catalysts tested for 'biodiesel' production.

Carbohydrates↗
PubMed2004

Organogelation of diacetylene cholesteryl esters having two urethane linkages and their photopolymerization in the gel state.

Various diacetylene cholesteryl esters having two urethane linkages were synthesized to study the relationship between their gelation properties and chemical structures. Most of these compounds form organogels in cyclohexane, and some compounds gelatinized hexane, diethyl ether, N,N-dimethylformamide, and ethanol. The cholesteryl moieties play an important role in gel formation, but IR spectroscopic measurements show that the main driving force for gelation is hydrogen bonding of the urethane groups. Upon UV irradiation, most of the gels polymerized to give polydiacetylenes, with concomitant changes from colorless to a variety of hues, such as dark blue, orange, and pink. The polymerization proceeds efficiently in cases where the gels change color to dark blue. The polymerization reached 52% chemical yield, with the quantum yield estimated to be at least 54. Solid-state NMR spectroscopy confirmed that polymerization in the gel state proceeds via 1,4-addition.

Acetylene↗
PubMed2003

Exfoliated nanosheets as a new strong solid acid catalyst.

Two-dimensional metal oxide sheets in HTiNbO(5) and HSr(2)Nb(3)O(10), cation-exchangeable layered metal oxides, were examined as solid acid catalysts. Exfoliation of HTiNbO(5) and HSr(2)Nb(3)O(10) in aqueous solutions formed colloidal single-crystal TiNbO(5)(-) and Sr(2)Nb(3)O(10)(-) nanosheets, which precipitated under an acidic condition to form aggregates of HTiNbO(5) nanosheets and HSr(2)Nb(3)O(10) nanosheets. Although esterification of acetic acid, cracking of cumene, and dehydration of 2-propanol were not catalyzed by original HTiNbO(5) because of the narrow interlayer distance, which prevents the insertion of organic molecules, HTiNbO(5) nanosheets functioned as a strong solid acid catalyst for the reactions. Nanosheets of HSr(2)Nb(3)O(10) exhibited no or slight catalytic activity for these reactions. NH(3) temperature-programmed desorption and (1)H magic-angle spinning nuclear magnetic resonance spectroscopy revealed that HTiNbO(5) nanosheets have strong Brønsted acid sites, whereas HSr(2)Nb(3)O(10) nanosheets do not.

Journal Article↗
PubMed2002

Isolation and structure of the mouse 14-3-3 eta chain gene and the distribution of 14-3-3 eta mRNA in the mouse brain.

14-3-3 protein is a brain-specific protein discovered by Moore and Perez, but at present is thought to be a multifunctional protein. To clarify the brain-specific function of the protein, we intend constructing a 14-3-3 eta gene knock-out mouse. As the first step of this process, we isolated the mouse 14-3-3 eta chain gene and determined its structure. The mouse gene is about 10 kb long and composed of two exons separated by a long intron. The transcription start site was identified and the polyadenylation signals (AATAAA) were found in exon 2 of the mouse gene. In the 5'-upstream sequence, we found several cis elements including a CRE sequence, a TATA box-like sequence, and a C/EBP element. Furthermore, the distribution of 14-3-3 eta mRNA in the mouse brain was examined by in situ hybridization histochemistry. The highest signals were found in the Purkinje cells of the cerebellum, the pyramidal cells of the hippocampus and the olfactory bulb neurons of the adult mouse. Neuronal expression of 14-3-3 eta in these regions mRNA may generally increase during postnatal brain development. The distribution of protein kinase C gamma in the mouse brain was also examined by immunohistochemistry. From the distribution of 14-3-3 eta mRNA and protein kinase C gamma in the mouse brain, the involvement of these compounds in the induction and maintenance of LTP was discussed.

14-3-3 Proteins↗
PubMed2002

Distribution and dynamics of hydrogen in the low-temperature phase of Mg(2)NiH(4) studied by solid-state NMR.

Distribution and dynamics of hydrogen atoms in the low-temperature phase of Mg(2)NiH(4) have been studied by means of (2)H and (1)H NMR for Mg(2)NiD(4) and Mg(2)NiH(4), respectively. (2)H NMR spectra have been measured in the temperature range between 200 and 340 K, and the line shapes were simulated. The temperature dependence of (2)H NMR spectra was quite well simulated assuming a distorted tetrahedral configuration and a pseudoisotropic rotation of the NiD(4) unit. The estimated jump frequency obeyed Arrhenius relation with a frequency factor of (0.8 +/- 0.6) x 10(13) Hz and an activation energy of 50.1 +/- 1.4 kJ/mol. (1)H NMR spectra were acquired from 240 to 360 K. The observed (1)H second moments were 202 kHz(2) in the rigid lattice (240 K) and 46.6 kHz(2) in a motional state (360 K). The value in the rigid lattice supported the tetrahedron model, and the value in a motional state indicated the isotropic rotation of the NiH(4) unit. Conclusively, the NiH(4) unit has the distorted tetrahedral configuration and undergoes the pseudoisotropic rotation.

Journal Article↗