ADDUCT FORMATION OF β-DIKETONATO LANTHANOIDS(III) WITH CARBOXYLIC ACIDS HAVING HYDROXYL AND METHOXYL GROUPS

Adduct formation of 2-thenoyltrifluoroacetonato(tta) lantha-num(III), europium(III), and ytterbium(I II) with α-pheny 1 1 actic, α-methoxy phenyl acetic, salicylic, and o-methoxy benzoic acids in chloroform has been studied by solvent extraction technique. It has been found that 1anthanoid(111) chelates form more stable adducts with these carboxylic acids in the sequence: Yb(tta)₃ < Eu(tta) ₃ < La(tta) ₃. The adduct formation constants as well as the separation factors obtained as the ratio of the constants between a pair of metals are the largest for α-phenyl lactic acid among these acids. The characteristics with α-phenyl 1actic acid would be caused by the action as bidentate unlike benzoic acid derivatives which work as monodentates owing to the internal complexa-tion through hydrogen bonding.     

Pd-catalyzed hydrosilylation polymerization of a dihydrosilane with diyne/triyne mixed systems affording crosslinked silylene-divinylene polymers and their properties

Treatment of a dihydrosilane (methylphenylsilane, 1) with mixtures of a diyne (p- or m-diethynylbenzene, 2a or 2b) and a triyne (1,3,5-triethynylbenzene, 3a or B,B′,B″-triethynyl-N,N′,N″-trimethylborazine, 3b; 1:2:3=100:95:5, 100:90:10, 100:80:20) in the presence of Pd-PCy₃ (Cy=cyclohexyl) catalyst gave new crosslinked silylenedivinylene polycarbosilanes. In TGA the resulting crosslinked polymers tended to show higher Td₅ values and higher char yields than the corresponding linear polymers. On the other hand, UV/vis absorption spectra of the crosslinked polymers obtained in the reactions of 2a or 2b with 3a exhibited increased broad peaks around 390 nm for 2a or 360 nm for 2b. Coincidently, their fluorescence spectra showed significant increase of the emission peaks in 400-550 nm. The crosslinked polymer derived from 2a and 3b, however, showed decrease of the absorption peak around 390 nm and profound depression of fluorescence peaks in 400-550 nm.     

Synthesis of geranyl acetate by lipase entrap-immobilized in cellulose acetate-TiO2 gel fiber

Lipase from Candida antarctica was entrap-immobilized in cellulose acetate-TiO₂ gel fiber (fiber-immobilized lipase) by the sol-gel method. Syntheses of geranyl acetate and citronellyl acetate catalyzed by the fiber-immobilized lipase were studied in heptane solution. Conversions reached 85% for geranyl acetate after 100 h, and 75% for citronellyl acetate after 80 h, and these values were almost identical to those for syntheses catalyzed by nonimmobilized lipase, although the reaction rate was decreased by immobilization. Compared to those of the non-immobilized lipase and commercially available immobilized lipase (Novozyme 435), the activity of the fiber-immobilized lipase was not particularly affected by changes in reaction conditions, such as bulk water content or substrate concentration. The fiber-immobilized lipase retained a high level of activity after six repeated uses, and almost no enzyme leakage from fiber was observed. However, the reactivity of the fiber-immobilized lipase was depressed at higher temperature, presumably due to dehydration by thermal contraction of the gel fiber.     

Acid-dyeable acrylic fibres copolymerised with amino alkyl methacrylates for differential cross-dyeing

The equilibrium adsorption of acid dyes on acrylic fibres copolymerised with dimethyl amino ethyl methacrylate has been investigated. A typical characteristic of this type of fibre is its excellent stable dyeability over a wide pH range. This is due to the strong basicity of alkylamino groups in the copolymerised component, which makes it possible to dye the fibre thoroughly even in a weakly acidic dyebath using a normal dyeing processes of acrylic fibre with cationic dye. Consequently it is useful for differential cross-dyeing in a single dyebath.     

Structurally Diverse Polyamines: Solid‐Phase Synthesis and Interaction with DNA

A versatile solid‐phase approach based on peptide chemistry was used to construct four classes of structurally diverse polyamines with modified backbones: linear, partially constrained, branched, and cyclic. Their effects on DNA duplex stability and structure were examined. The polyamines showed distinct activities, thus highlighting the importance of polyamine backbone structure. Interestingly, the rank order of polyamine ability for DNA compaction was different to that for their effects on circular dichroism and melting temperature, thus indicating that these polyamines have distinct effects on secondary and higher‐order structures of DNA.     

Profiling and Imaging of Phospholipids in Brains of Abcd1‐Deficient Mice

ABCD1 is a gene responsible for X‐linked adrenoleukodystrophy (X‐ALD), and is critical for the transport of very long‐chain fatty acids (VLCFA) into peroxisomes and subsequent β‐oxidation. VLCFA‐containing lipids accumulate in X‐ALD patients, although the effect of ABCD1‐deficiency on each lipid species in the central nervous system has not been fully characterized. In this study, each phospholipid and lysophospholipid species in Abcd1‐deficient mice brains were profiled by liquid chromatography‐mass spectrometry. Among the phospholipid and lysophospholipid species that are significantly more enriched in Abcd1‐deficient mice brains, VLCFA were present in 75, 15, 5, 4, and 1 species of phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, lysophosphatidylcholine, and lysophosphatidylethanolamine, respectively. Most VLCFA were incorporated at the sn‐1 position of phosphatidylcholine and phosphatidylethanolamine. Among the phospholipid species that are significantly less enriched in Abcd1‐deficient mice brains, odd‐numbered saturated or mono‐unsaturated fatty acyl moieties are contained in all phosphatidylcholine species. In addition, a number of phosphatidylglycerol, phosphatidylinositol, and phosphatidylserine species contained highly unsaturated fatty acyl moieties. Intriguingly, 44:1 phosphatidylcholine with VLCFA was mainly distributed in the gray matter, such as the cortex, but not in the white matter in the cerebrum and cerebellum. These results show that ABCD1‐deficiency causes metabolic alternation of long‐chain fatty acids and VLCFA. Moreover, our results imply a molecular mechanism for the incorporation of saturated or monounsaturated VLCFA into the sn‐1 position of phospholipids, and also indicate that the distribution of phospholipids with VLCFA may correlate with the development of X‐ALD.     

A novel hybrid adsorption heat pump water heater

A hybrid adsorption heat pump water heater has been studied for domestic use. It is a water heater with dual heat sources, and it combines the performances of adsorption heat pumps and conventional gas boilers. Moreover, functional adsorbent material‐zeolite (FAM‐Z02, Mitsubishi Chemicals) and water are a new adsorption pair for adsorption heat pumps. This article describes the operation, design, and performance analysis of one such water‐heating device. The experimental results showed that the hybrid water heater in the whole year has a stable COP even at low ambient temperature. The hybrid water heater can thus achieve high energy efficiency.     

Network structures and dynamics of dry and swollen poly(acrylate)s. Characterization of high- and low-frequency motions as revealed by suppressed or recovered intensities (SRI) analysis of C NMR

We recorded temperature-dependent high-resolution ¹³C NMR spectra of dry and swollen poly(acrylate)s [poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(tetrahydrofurfuryl acrylate) (PTHFA)] by dipolar decoupled-magic angle spinning (DD-MAS) and cross-polarization-magic angle spinning (CP-MAS) methods, to gain insight into their network structures and dynamics. Suppressed or recovered intensities (SRI) analysis of ¹³C CP-MAS and DD-MAS NMR was successfully utilized, to reveal portions of dry and swollen polymers which undergo fast and slow motions with fluctuation frequencies in the order of 10⁸ Hz and 10⁴-10⁵ Hz, respectively. Fast isotropic motions with frequency higher than 10⁸ Hz at ambient temperature were located to the portions in which ¹³C CP-MAS NMR signals of swollen PMEA were selectively suppressed. In contrast, low-frequency motion was identified to the portions in which ¹³C DD-MAS (and CP-MAS) signals are most suppressed at the characteristic suppression temperature(s) T_s. Network of PMEA gels (containing 7 wt% of water) turns out to be formed by partial association of backbones only, as manifested from their T_s gradient at lowered temperature, whereas networks of PHEMA (containing 40 wt% of water) and PTHFA (9 wt% of water) gels are tightly formed through mutual inter-chain associations of both backbones and side-chains, as viewed from the raised T_s values for both near at ambient temperature. It is also interesting to note that flexibility of gel network (PMEA > PTHFA > PHEMA) characterized by the suppression temperature T_s (PMEA < PTHFA < PHEMA) is well related with a characteristic parameter for biocompatibility such as the production of TAT (thrombin-antithrombin III complex) as a marker of activation of the coagulation system.     

Inhibitory Effects of Cholesterol Derivatives on DNA Polymerase and Topoisomerase Activities, and Human Cancer Cell Growth

This paper describes the inhibitory activities of cholesterol derivatives such as cholesterol, sodium cholesteryl sulfate, cholesteryl-5α, 6α-epoxide, cholesteryl chloride, cholesteryl bromide, and cholesteryl hemisuccinate (compounds 1–6, respectively) against DNA polymerase (pol), DNA topoisomerase (topo), and human cancer cell growth. Among the compounds tested, compounds 2 and 6 revealed themselves to be potent inhibitors of animal pols, and the IC₅₀ values for pols were 0.84–11.6 and 2.9–148 μM, respectively. Compounds 2, 3 and 6 inhibited the activity of human topo II, with IC₅₀ values of 5.0, 12.5 and 120 μM, respectively. Compounds 2, 3 and 6 also suppressed human cancer cell (promyelocytic leukemia cell line, HL-60) growth, and LD₅₀ values were 8.8, 20.2 and 72.3 μM, respectively, suggesting that cell growth inhibition had the same tendency as the inhibition of topos rather than pols. Compounds 2 and 6 arrested the cells in S and G2/M phases, compound 3 arrested the cells in the G2/M phase, and these compounds also increased sub-G1 phase in the cell cycle. These results suggested that the effect of cell cycle arrest might be effective on both pols and topos activities. From these findings, the action mode of cholesterol derivatives as anti-cancer compounds is discussed.