Interactions between temperature-sensitive hydrogel microspheres and granulocytes

Poly(N-isopropylacrylamide) (PNIPAM) has a low critical solution temperature (LCST) at 32°C in water and the hydrophilicity changes through the LCST. The microspheres whose surface was composed of PNIPAM exhibited phase transition behavior around 32°C. Therefore, the interactions between PNIPAM micropheres and granulocytes depended on the temperature. That is, the oxygen consumption and active oxygen production by cells in contact with PNIPAM-containing microspheres and adhesion of the microspheres to the cell surface were more enhanced above the LCST of PNIPAM than below it, whereas no significant temperature dependence of cell–microspheres interaction was observed in nonthermosensitive microsphere systems. It was suggested that the function of cells could be controlled with temperature using the temperature-sensitive microspheres.     

POLYETHYLENE GLYCOL-MODIFIED HEMATOPORPHYRIN AS PHOTOSENSITIZER

Abstract— Hematoporphyrin, having two carboxylic groups, was coupled with α-(3-aminopropyl)-ω-methoxypoly(oxyethylene), PEG-NH₂, through acid-amide bond formed with carbodtimide. PEG-modified hematoporphyrin was readily soluble not only in neutral aqueous solution but also in organic solvents. Its absorption spectrum showed a sharp band at 376 nm in neutral aqueous solution and at 403 nm in benzene. Modified hematoporphyrin acted as a photosensitizer; imidazole and indole were photooxidized in organic solvents such as benzene or chloroform, and uric acid was also photooxidized in neutral aqueous solution.     

Photodegradation of polyethylene in the presence of ferric salt: Influence of ferric acetylacetonate on model compounds

The influence of ferric acetylacetonate [Fe(acac)₃] on the photodegradation of model compounds of polyethylene (PE) was examined. By studying electron-spin-resonance (ESR) spectra of photoirradiated compounds such as 1-octene and 1,7-octadiene, which contain carbon double bonds, Fe(acac)₃ was found to accelerate the formation of allyl radical by contact with them. On the other hand, Fe(acac)₃ suppressed the radical formation based on Norrish type I reaction in a carbonyl group of compounds such as 2-octanone and 3-octanone. Based on the study of ultraviolet (UV) spectra as well as ESR spectra on photoirradiated samples, the influence of Fe(acac)₃ on the photodecomposition of model compounds of PE was discussed. Finally, the discussion turned to the mechanism of photodecomposition of PE in the presence of ferric salt.     

Photochemical aromatic hydroxylation by aromatic amine N-oxides: remarkable solvent effect on NIH-shift

Photooxygenations of 4-²H-anisole ($\text{3}$) and o-xylene ($\text{5}$) by 3-methylpyridazine 2-oxide ($\text{1}$) or pyridine 1-oxide ($\text{2}$) were studied in a variety of solvents at varying irradiation temperatures. Remarkable solvent effect on NIH-shift coupled with their hydroxylation processes was observed.     

Application of non-thermal atmospheric pressure ac plasmas to the carbon dioxide reforming of methane

Methane conversions of 11.9%, yields of hydrogen as high as 23.3% and energy yields of 1.0 mol H₂/kWh have been achieved from CO₂ reforming of CH₄ in non-thermal, atmospheric pressure plasma reactors with Pt coated electrodes. Two reactors have been studied. A novel fan type reactor consisting of a movable rotor and immobile stator produced the highest yields in contrast to a tube type (silent discharge) reactor with a glass dielectric barrier. Conversions, yields of hydrogen and energy yields (expressed as mol H₂/kWh) were studied for CO₂/CH₄ concentrations of 1.1% and 5.0% in He as a function of flow rate and input voltage. Hydrogen yields are observed to increase as the input voltage is increased from 411 V to 911 V and the flow rate is decreased from 100 cc/min to 30 cc/min. Energy yields vary only slightly with input voltage and flow rate. Hydrogen yields show little dependence on CO₂/CH₄ concentrations, but energy yields are approximately five times greater for the 5.0% mixture than the 1.1% mixture. Selectivities to H₂, CO, coke, and low molecular weight hydrocarbons were also evaluated and compared to data obtained without CO₂ in the feed. Hydrogen selectivities of nearly 100% were obtained, with small amounts of ethane and propane as the only observed side products and the selectivites were approximately the same whether CO₂ was present or absent in the mixture. However, the reaction proceeds much more cleanly when CO₂ is present, producing CO. The syngas product has an H₂ : CO ratio of 1.5 with the fan type reactor and 0.67 with the tubular reactor. In the absence of CO₂, coke is the main carbonaceous product. Under all conditions studied the fan type reactor demonstrated higher methane conversions (up to 11.9%) and selectivities to hydrogen.     

Distributed computing and NMR constraint-based high-resolution structure determination: applied for bioactive Peptide endothelin-1 to determine C-terminal folding

Distributed computing has been implemented to the solution structure determination of endothelin-1 to evaluate efficiency of the method for NMR constraint-based structure calculations. A key target of the investigation was determination of the C-terminal folding of the peptide, which had been dispersed in previous studies of NMR, despite its pharmacological significances. With use of tens of thousands of random initial structures to explore the conformational space comprehensively, we determined high-resolution structures with good convergences of C-terminal as well as previously defined N-terminal structures. The previous studies had missed the C-terminal convergence because of initial structure dependencies trapped in localized folding of the N-terminal region, which are strongly constricted by two disulfide bonds.     

羟基羧酸钛(Ⅲ)配合物的合成和热性质研究

三氯化钛分别与苹果酸铵、酒石酸铵和柠檬酸铵反应，制得三种新的固态配合物：苹果酸羟基钛(Ⅲ)、酒石酸羟基钛(Ⅲ)和柠檬酸钛(Ⅲ)(化学式分别为Ti(OH)(C₄H₄O₅)·1.5H₂O、Ti(OH)(C₄H₄O₆)·1.5H₂O和Ti(C₆H₅O₇)·1.5H     

Asymmetric induction copolymerization. Cationic copolymerization of l-menthyl vinyl ether with indene and acenaphthylene

l-Menthyl vinyl ether (l-MVE) was homopolymerized and copolymerized with the monomers indene (IN) and acenaphthylene (ANp) by BF₃OEt₂ as a catalyst. The chiral menthyl substituent was cloven from the homopolymers and copolymers using dry-hydrogen bromide gas. After the removal of optically active menthyl group, poly(vinyl alcohol) (PVA) from l-MVE homopolymer was optically inactive, and copolymers (VA-IN, VA-ANp) from l-MVE-IN and l-MVE-ANp copolymers were still optically active. Hence, in the case of l-MVE homopolymer, it was concluded that asymmetric induction in the polymer main chain can only produce pseudoasymmetry. In the case of l-MVE-IN and l-MVE-ANp copolymers, it was found that asymmetric induction proceeded in the copolymer main chain and was caused by the influence of chiral menthyl group.     

Asymmetric induction radical copolymerization of optically active l-menthyl vinyl ether with vinylene carbonate and indene

The copolymerizations of l-menthyl vinyl ether (l-MVE) with the monomers vinylene carbonate (VCA) and indene (IN) were carried out in benzene with azobisisobutyronitrile (AIBN) as an initiator to obtain optically active copolymers. The optically active l-menthyl residue from the copolymer main chain was removed using dry hydrogen bromide gas. After the ether cleavage reaction, the copolymers prepared (VA–VCA and VA–IN) were still optically active, and hence it was found that asymmetric induction had taken place in the copolymer main chain. The optical rotatory dispersion (ORD) and circular dichroism (CD) data of the original and ether-cloven copolymers were also determined.     

Determination of glutamate-pyruvate transaminase activity in blood serum with a pyruvate oxidase/poly(vinyl chloride) membrane sensor

Pyruvate oxidase (E.C. 1.2.3.3.) is immobilized by adsorption on a wet PVC membrane. Glutamate-pyruvate transaminase activity (5–1600 IU l^?1) in serum is determined by a pyruvate oxidase sensor consisting of the immobilized pyruvate oxidase coupled to a platinum electrode for measuring hydrogen peroxide, after an l-alanine—α-ketoglutarate reaction. The assay requires ?60 s, and has a precision of 2–3%. Endogenous pyruvate should not interfere if measurements are made > 30 s after starting the reaction.