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991.
Tomoyuki Ohishi Ryuji Sugi Akihiro Yokoyama Tsutomu Yokozawa 《Journal of polymer science. Part A, Polymer chemistry》2006,44(17):4990-5003
Chain-growth polycondensation of 3-(alkylamino)benzoic acid alkyl esters 1 was investigated for obtaining poly(m-benzamide)s with defined molecular weights and low polydispersities. Polymerization conditions were first studied to find that ethyl 3-(octylamino)benzoate ( 1b ) polymerized in a chain polymerization manner in the presence of lithium 1,1,1,3,3,3-hexamethyldisilazide (LiHMDS) as a base and phenyl 4-methylbenzoate ( 2b ) as an initiator in THF at 0 °C. The molecular weight of the polymer was controlled by the feed ratio of monomer to initiator. The polymerization of 1c – i with a variety of N-alkyl groups was then carried out under the established conditions to yield well-defined poly(m-benzamide)s, which showed higher solubility than those of the corresponding poly(p-benzamide)s. Furthermore, the 4-octyloxybenzyl group on the amide nitrogen in poly 1i was removed by treatment with trifluoroacetic acid (TFA) to give N-unsubstituted poly(m-benzamide) (poly 1j ) with a low polydispersity, which is soluble in DMAc and DMSO, contrary to the para-substituted counterpart. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4990–5003, 2006 相似文献
992.
Tsutomu NAKADA 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2010,86(6):630-642
Mammals face drastic environmental changes at birth. Appropriate adjustments of various systems must take place rapidly to accommodate this once in a life time event. The brain undergoes significant adjustments as well, the most obvious of which is in its need to meet the drastic increase in energy consumption at the neuronal cell membrane due to the explosive increase in neural activities after birth. Actual changes were found to be taken place in two systems, namely, acid base balance control and cytosolic energy transport. The adjustments are accomplished by converting cytosol microenvironment from a taurine rich fetal type environment to an N-acetyl-aspartate (NAA) rich adult type environment during the post-natal period. High concentrations of taurine are necessary to provide effective buffering in the fetal brain, because the fetus cannot utilize the adult type of pCO2 dependent acid–base balance control system, namely respiration driven pCO2 changes. To accommodate the significantly higher demand of energy consumption at the membrane due to the increased neuronal activities, taurine has to be replaced by NAA, since the latter facilitates HEP transport from mitochondria to the membrane by passive diffusion. 相似文献
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995.
Keisuke Tomita Tsutomu Ono 《Journal of polymer science. Part A, Polymer chemistry》2009,47(3):762-770
Sodium polyaspartate (PAspNa) derivatives with vinylbenzyl pendant groups (VBA‐PAspNa) were synthesized by reaction of poly(succinimide) (PSI) and vinylbenzylamine (VBA), and hydrolysis by sodium hydroxide (NaOH) solution. VBA‐PAspNa is a macromonomer with multiple vinyl groups in the side chain. Submicron sized polymeric particles were prepared by dispersion copolymerization of styrene with VBA‐PAspNa in a mixture of ethanol and water. Particle diameter decreased with increasing concentration and vinyl group fraction of VBA‐PAspNa. When compared with the particle diameter prepared using PAspNa or benzylamine‐modified PAspNa (BA‐PAspNa) as a dispersion stabilizer without vinyl groups, the particles prepared with VBA‐PAspNa were an order smaller than those prepared with PAspNa or BA‐PAspNa. The particles after refinement show an adequate negative ζ‐potential. From this result, we clarified the presence of PAspNa chains anchored onto the particle surface. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 762–770, 2009 相似文献
996.
Makoto Muranaka Tsutomu Ono 《Journal of polymer science. Part A, Polymer chemistry》2009,47(20):5230-5240
Monodisperse poly(D ,L ‐lactide) (PDLLA) microspheres were prepared by dispersion polymerization of D ,L ‐lactide in xylene/heptane (1/2, v/v) with poly[(dodecyl methacrylate)‐co‐(2‐hydroxyethyl methacrylate)] (P(DMA‐co‐HEMA)) as a dispersion stabilizer. P(DMA‐co‐HEMA) contains hydroxy groups, which act as an initiation group for pseudoanionic dispersion polymerization. The best coefficient of variation (CV) values concerning particle diameter distribution and the particle diameter of obtained PDLLA microspheres were 3.7% and 5.3 μm, respectively. The particle diameter decreased with increasing concentration of P(DMA‐co‐HEMA) and HEMA maintained low CV (<10%) values. As a result, monodisperse PDLLA microspheres ranging from 1.3 to 5.3 μm were obtained. In addition, it was found that monodisperse PDLLA microspheres were obtained by sufficient capture of growing polymers and monomers in the particle growth stage. Therefore, the HEMA concentration in P(DMA‐co‐HEMA) strongly affecting the capturing capability is the most important factor. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5230–5240, 2009 相似文献
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998.
Takashi Mino Hiroaki Shindo Tomoko Kaneda Tomoko Koizumi Yoshio Kasashima Masami Sakamoto Tsutomu Fujita 《Tetrahedron letters》2009,50(38):5358-432
Palladium-catalyzed Mizoroki-Heck reaction of allyl aryl ethers with aryl iodides gave aryl cinnamyl ethers using a catalytic amount of Pd(OAc)2 in DMF at 50 °C with phosphine-free hydrazone as a ligand in good yields. 相似文献
999.
Tsutomu Ohkubo Shinsuke Inagaki Jun Zhe Min Daiki Kamiya Toshimasa Toyo'oka 《Rapid communications in mass spectrometry : RCM》2009,23(13):2053-2060
The primary structure of the deteriorated recombinant human basic fibroblast growth factor (rhbFGF) was determined by ultra‐performance liquid chromatography and electrospray ionization quadrupole time‐of‐flight mass spectrometry (UPLC/ESI‐QTOF‐MS) with in‐source collision‐induced dissociation (CID). The rhbFGFs before and after treatment with hydrogen peroxide (H2O2) were separated using an ACQUITY UPLC BEH300 C18 column (1.7 µm, 150 mm × 2.1 mm i.d.) with a gradient elution of a mixture of water/acetonitrile containing 0.1% formic acid. The separated proteins were then detected by a SYNAPT? High Definition Mass Spectrometry? system (SYNAPT‐MS). Two methionine (Met) residues in the rhbFGF structure were oxidized to Met‐sulfoxide (Met‐O) in 0.03% H2O2 at pH 2.0. As the result, three peaks, except for the peak of rhbFGF, appeared on the chromatogram. The three proteins corresponding to each peak were estimated as the denatured rhbFGFs including the Met‐O residue(s) with TOF‐MS. Furthermore, the position of the Met‐O residue(s) was efficiently identified by UPLC/ESI‐QTOF‐MS using the in‐source CID technique. The proposed method seems to be very useful for the structural elucidation of proteins, because the oxidized Met residues in rhbFGF were easily and rapidly identified. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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