Inhibition of increasing effect of vanadate on glycogen content and lipoprotein lipase activity in fat pads by 5-N,N-hexamethylene amiloride.

Sodium orthovanadate (vanadate) increased the glycogen content in isolated rat fat pads in a dose-dependent manner up to 2 mM. Biochanin A, a specific inhibitor of tyrosine kinases, inhibited the increasing effect of vanadate or insulin on both glycogen content and lipoprotein lipase (LPL) activity in fat pads. The increasing effect of vanadate on glycogen content was not decreased by the replacement of Na+ with choline ion in the incubation medium. 5-N,N-Hexamethylene amiloride, a potent inhibitor of the Na+/H+ exchange system, showed a 50%-inhibition of the vanadate-increased LPL activity and glycogen content at 25 and 80 microM, respectively, suggesting that mechanisms of the inhibition differ in part between the vanadate actions. Furthermore, a similar inhibitory profile of the vanadate-increased glycogen content was observed with incubation in the presence of absence of Na+ in the medium. These results suggest that the activation of the Na+/H+ exchange system by vanadate is not involved in an increase in the glycogen content in fat pads.     

Preparation and regioselective SN2' reaction of novel gem-difluorinated vinyloxiranes with RLi

A series of hitherto unknown 3,4-epoxy-1,1-difluorobutenes were prepared from the readily accessible alpha,beta-epoxy ketones and these compounds were found to undergo regioselective S(N)2' reactions with hard RLi nucleophiles occurring at the highly positively charged terminal fluorine-possessing sp(2) carbon atom in quite sharp contrast to the cases of the corresponding nonfluorinated vinyloxiranes which only attained a low level of regioselectivity. Addition of HMPA substantially improved the products' olefinic stereoselectivity. Theoretical calculations were used to qualitatively explore the nature of selectivity in these reactions.     

Chromic and fluorescence response system based on the dihydrophenanthroline-bipyridine skeleton: dynamic redox behavior and metal binding properties

The spiro-acridan/acridinium-based dynamic redox pair (1/2²⁺) transduces the electrochemical input into UV-vis and fluorescence spectra, whereas the 2,2′-bipyridine units in 1 works as a bidentate ligand for metal ions. X-ray structural analyses of this redox pair and the corresponding Zn-complexes [1-ZnI₂/2²⁺-Zn²⁺(OTf⁻)₄] demonstrate drastic structural changes upon electron-transfer, thus metal binding properties are modified by redox reactions.     

Moment asymptotics for the parabolic Anderson problem with a perturbed lattice potential

The parabolic Anderson problem with a random potential obtained by attaching a long tailed potential around a randomly perturbed lattice is studied. The moment asymptotics of the total mass of the solution is derived. The results show that the total mass of the solution concentrates on a small set in the space of configuration.     

Five non‐synonymous SNPs in the gene encoding human deoxyribonuclease I‐like 2 implicated in terminal differentiation of keratinocytes reduce or abolish its activity

Several non‐synonymous SNPs in the human deoxyribonuclease I‐like 2 (DNase 1L2) gene responsible for DNA degradation during terminal differentiation of epidermal keratinocytes have been identified. However, only limited population data are available, and furthermore the effect of these SNPs on the DNase 1L2 activity remains unknown. Genotyping of all of the 17 SNPs was performed using the PCR‐RFLP method in three ethnic groups including 14 different populations. A series of amino acid‐substituted DNase 1L2 corresponding to each SNP was expressed, and its activity was measured. All of the six non‐synonymous SNPs exhibited a mono‐allelic distribution, whereas the distribution of some SNPs other than exonic ones was ethnicity‐dependent. Each of the minor alleles in SNPs, p.Ala20Asp, p.Val104Leu, p.Asp197Ala, p.Glu274Lys and p.Asp287Asn, among the non‐synonymous SNPs produced low or no activity‐harbouring DNase 1L2. DNase 1L2 is well conserved, retaining full levels of enzymatic activity, with regard to these exonic SNPs in human populations. It seems plausible to assume that these SNPs affecting the activity may be one of the factors responsible for a genetic pre‐disposition for failure of differentiation‐associated cell death in various keratinocyte lineages, thereby leading to the development of parakeratosis. Our results may have clinical implications in relation to the pathogenesis of parakeratosis.     

Influence of plasticizer content on the transition of electromechanical behavior of PVC gel actuator

The actuation performance of plasticized poly(vinyl chloride) (PVC) gel actuators in an electric field depends on their chemical composition and electrical and mechanical properties. The influence of plasticizer (dibutyl adipate) content on electromechanical behavior of PVC gels was investigated by impedance spectroscopy and space charge measurement. By plasticizing the PVC, the dielectric constant and space charge density of PVC gel were drastically increased at 1:2 w/w ratio of PVC to plasticizer. To apply the results obtained from the impedance spectroscopy and space charge measurement, electrostatic adhesive forces generated between the PVC gel and the anode were measured. The electrostatic adhesive force at the anode was also dramatically increased at the same plasticizer content. All of the results indicated a transition of electromechanical behavior of PVC gel in the electric field, which was considered to originate from the orientation of polarized plasticizer molecules and dipole rotation of PVC chains. By using the electrostatic adhesive force of PVC gel derived from the electromechanical transition, a new electroactive actuator can be developed for novel applications.