Electronic structures and charge-transfer spectra of tris[2.2.2]paraxylylene and related compounds

Electronic spectra of tris[2.2.2]paraxylylene (3°-PX) and some related compounds were measured in order to investigate the electronic interaction (pπ-pπ and pσ-pσ type) between “normal” (undistorted) benzene rings. 3°-PX showed a large hypochromic effect, i.e., its oscillator strength was observed to be 0·61 times of that of the corresponding linear polyparaxylylene. Charge-transfer (CT) spectra between these compounds and some electron acceptors were also studied. MO calculations (the VI/1, CNDO/2 and CI methods) were carried out in order to elucidate the electronic structure of 3°-PX and also the CT interactions between tetracyanoethylene and 3°-PX, benzene, toluene or p-xylene.     

A satellite of the grand Furuta inequality and its application

The grand Furuta inequality has the following satellite (SGF;$t\in [0\text{,}1]$), given as a mean theoretic expression:$A?B>0\text{,}t\in [0\text{,}1]?A^{-r+t}{\#}_{\frac{1-t+r}{(p-t)s+r}}(A^t{?}_s{B}^p)?B\text{for}r?t\text{;}p\text{,}s?1\text{,}$where ${\#}_{\alpha }$ is the $\alpha$-geometric mean and ${?}_s$ ($s?[0\text{,}1]$) is a formal extension of ${\#}_{\alpha }$. It is shown that (SGF; $t\in [0\text{,}1]$) has the Löwner–Heinz property, i.e. (SGF; $t=1$) implies (SGF;t) for every $t\in [0\text{,}1]$. Furthermore, we show that a recent further extension of (GFI) by Furuta himself has also the Löwner–Heinz property.     

Facile synthesis of enantiopure 1,1′-binaphthyl-2,2′-dicarboxylic acid via lipase-catalyzed kinetic resolution

Enantiopure 1,1′-binaphthyl-2,2′-dicarboxylic acids (R)-1 and (S)-1 have been synthesized through the lipase-catalyzed kinetic resolution of the racemic 2,2-bis(hydroxymethyl)-1,1′-binaphthyl (±)-2 and subsequent oxidation of the hydroxymethyl groups.     

Semisynthesis of isetexane diterpenoid analogues and their cytotoxic activity

Isetexane diterpene analogues were semisynthesized from demethylsalvicanol isolated from Perovskia abrotanoides (Labiatae). The structure and cytotoxic activity relationships (SAR) of the natural parent diterpene, demethylsalvicanol, and its semisynthetic analogues were studied by using P388 murine leukemia cells.     

Comment: Proton transfer in solid benzoic acid. Reply to the comment by K. Furić

In response to the Comment of Furi?, attention is drawn to four points: the dinstinction between the reaction and normal coordinates, zero-point energy, an alternative of the NMR results, and ab initio calculations.     

One-pot enantioselective syntheses of iminosugar derivatives using organocatalytic anti-michael-anti-aza-Henry reactions

Organocatalyst-controlled asymmetric anti-Michael reactions of (tert-butyldimethylsilyloxy)acetaldehyde with a range of nitroolefins, followed by an intermolecular aza-Henry reaction with imine, provided iminosugar derivatives with five contiguous stereocenters in very high enantiomeric excess in one pot. The stereochemistry of the aza-Henry reaction was substrate controlled and is explained by a six-membered cyclic transition-state model.     

Increased levels of 8-hydroxy-2'-deoxyguanosine in Drosophila larval DNA after irradiation with 364-nm laser light but not with X-rays

Exposure to UVA light causes damage to cellular components such as DNA and membrane lipids. We showed previously that UVA irradiation can induce mutations in Drosophila larvae and that the major lesions responsible for mutations were not thymidine dimers when wavelengths tested became longer. The use of a longer wavelength with UVA laser apparatus (364 nm) has made it possible to test the effects of this powerful light in biological organisms. In the present study, we irradiated third instar larvae of the urate-null Drosophila mutant strain y v ma-l, which is sensitive to oxidative stress, and compared the effects of 364 nm light irradiation with the effects of X-rays. To assay viability, some of the larvae were kept at 25 degrees C until they eclosed in order to obtain a measure of viability. The remaining larvae were used to measure the amount of 8-hydroxydeoxyguanosine (8-OHdG), an indicator of oxidative DNA damage. The amount of 8-OHdG increased and viability decreased in response to increased UV dose in both the y v ma-l and wild-type strains. With irradiation of 600 kJ m(-2), 8-OHdG/10(6)dG was 7.2 +/- 3.2 and 6.2 +/- 2.0 in y v ma-l and wild-type strains, respectively, whereas the respective levels were 2.2 +/- 0.6 and 2.3 +/- 0.8 without irradiation. Our results indicated that irradiation with a 364-nm laser light caused significant oxidative damage in Drosophila larval DNA; however, induction of the damage was not prohibited by urate. To the best of our knowledge, this is the first report of a study in whole animals that shows increased levels of 8-OHdG in response to 364-nm UVA. X-ray ionizing radiation is also thought to generate reactive oxygen species in irradiated cells. We found that the amount of 8-OHdG in DNA following X-ray radiation remained unchanged in both strains, though survival rates were affected. X-ray-generated oxidative damage in Drosophila cells was followed by cell death but not DNA base oxidation, and the damage was suppressed by urate. The overall results suggest significant differences in the major in vivo oxidative damage caused by 364-nm light and X-rays.     

Uphill transport of acetate anion through synthetic polymer membranes with pyridinium cations as fixed carrier

Acetate anion was transported against its concentration gradient through a synthetic polymer membrane with pyridinium cation units as fixed carrier. Two synthetic membrane materials were studied, poly(1-butyl-4-vinylpyridinium iodide-co-acrylonitrile) and poly(1-methyl-4-vinylpyridinium iodide-co-acrylonitrile). Acetate anion was transported by an antiport mechanism, with halogen ion transfer as driving force.     

Active and selective transport of halogen ions through poly (1-vinylimidazole-co-styrene) membranes

A membrane made of poly(1-vinylimidazole-co-styrene) is able to actively and selectively transport halogen ions. Halogen ions were transported not only by an antiport mechanism with OH^? transfer, but also by a symport mechanism with H⁺ transfer. This variation in transport mechanism can be explained by a polarity change of the membrane. The transport of halogen ions is represented by flux equations, and the selectivity predicted theoretically is compared to the experimental value.