One-Pot Preparation of Methacrylate/Styrene Alternating Copolymers via Radical Copolymerization and Alcoholysis Modification: Sequence Impacts on Glass Transition Temperature

A series of methacrylate/styrene alternating copolymers were efficiently and systematically synthesized via alternating copolymerization of saccharin methacrylamide (1) with styrene and subsequent one-pot alcoholysis transformation with alcohols. The saccharin amide bond in 1 was stable enough that 1 was used as a bench-stable monomer, but the bond became reactive toward alcohols after the copolymerization. Thanks to the specific feature, the postpolymerization modification could be performed under mild conditions despite easy handling of the monomer. The quantitative transformation as well as the alternating sequence were certainly supported by 1H NMR and MALDI-TOF-MS analyses. The alternating copolymers carrying relatively short alkyl pendants expressed lower glass transition temperatures than those of the statistical counterparts. Moreover, the alternating copolymerization was controlled via a RAFT polymerization system, affording a unique block copolymer composed of alternating copolymer segments

Self-assembly and salt-induced thermoresponsive properties of amphiphilic PEG/cation random terpolymers in water

Herein, we report the self-assembly and salt-induced thermoresponsive properties of amphiphilic random terpolymers consisting of hydrophilic poly(ethylene glycol) (PEG) and quaternary ammonium cations, and hydrophobic dodecyl groups in water. The random terpolymers self-assembled into size-controlled multichain micelles in pure water or in water containing NaCl. The micelle size increased upon increasing the content of the cationic groups in the total hydrophilic monomer units (∼50 mol%) and turned larger in the presence of NaCl than that in pure water. More uniquely, the random terpolymer micelles showed lower critical solution temperature-type solubility in water containing salts such as NaCl, while the solutions of the polymer micelles in pure water were transparent even upon heating to over 90 °C. The cloud point (Cp) temperature of the aqueous polymer micelle solution was controlled by the concentration of NaCl or the composition of the terpolymers. The critical concentration of NaCl for thermoresponsive solubility depended on the PEG/cation composition of the terpolymers. For example, a PEG/cation/dodecyl (1/1/2) random terpolymer micelle exhibited thermoresponse in water containing more than 0.5 M NaCl; the Cp of the aqueous solution decreased from 86 °C to 59 °C upon increasing the concentration of NaCl from 0.5 M to 2.0 M. The Cp of their terpolymers increased upon increasing the content of quaternary ammonium cations

Anthranilamide-protected vinylboronic acid: rational monomer design for improved polymerization/transformation ability providing access to conventionally inaccessible copolymers

We have studied several protecting groups for vinylboronic-acid derivatives as monomers in radical polymerizations with the objective to improve the polymerization ability and C–B bond-cleaving post-transformation performance. Anthranilamide (aam)-protected vinylboronic acid (VBaam) exhibited experimentally a relatively high polymerization activity, which was theoretically corroborated by density functional theory (DFT) calculations that revealed a peculiar effect of the interaction between the aam groups on the polymerization behavior. The VBaam units in the copolymers can subsequently be transformed into vinyl alcohols or into ethylene units through C–B-bond-cleaving side-chain replacement, which affords valuable copolymers such as poly(vinyl alcohol-co-styrene), poly(ethylene-co-styrene), and poly(ethylene-co-acrylate)

L'acide polymethacrylique est thermosensible en solvant organique

International audienc

Relationship between postprandial glucose level and carotid artery stiffness in patients without diabetes or cardiovascular disease

BACKGROUND: The aim of this study was to evaluate the relationship between postprandial glucose level and atherosclerosis in patients without diabetes and cardiovascular disease by determining carotid ultrasonographic variables and serum levels of 1,5-anhydroglucitol (1,5-AG). METHODS: The subjects were 72 patients without diabetes and cardiovascular disease being treated for hypertension or dyslipidemia. The clinical characteristics of all subjects, including the serum level of 1,5-AG, which appears to be well suited for monitoring postprandial hyperglycemia, were evaluated after an overnight fast. The average intima-media thickness (IMT) and the average pulsatility index (PI) of the right and left common carotid arteries were determined with high-resolution ultrasonography and used as ultrasonographic variables. The subjects were divided into a Lower 1,5-AG group (n = 36) and a Higher 1,5-AG group (n = 36). We evaluated the relationship between clinical characteristics and ultrasonographic variables of the carotid artery in both groups. RESULTS: The average PI in the Lower 1,5-AG group was significantly higher than that in the Higher 1,5-AG group, but the average IMT did not differ between the groups. Linear regression analysis, with the ultrasonographic variables as the dependent variables, with 1,5-AG as the independent variable, and adjusted for other clinical characteristics, showed significant correlation between 1,5-AG and the PI but not between 1,5-AG and IMT. CONCLUSION: Our results suggest that postprandial hyperglycemia increases carotid artery stiffness, but not morphological change, in patients without diabetes or cardiovascular disease

Degenerative Lumbar Spondylolisthesis with Spinal Stenosis: A Comparative Study of 5-Year Outcomes Following Decompression with Fusion and Microendoscopic Decompression

Study DesignRetrospective review of prospectively collected outcome data.PurposeTo compare 5-year outcomes following decompression with fusion (FU) and microendoscopic decompression (MED) in patients with degenerative lumbar spondylolisthesis (DLS) and to define surgical indication limitations regarding the use of MED for this condition.Overview of LiteratureThere have been no comparative studies on mid- or long-term outcomes following FU and MED for patients with DLS.MethodsForty-one consecutive patients with DLS were surgically treated. Sixteen patients first underwent FU (FU group), and 25 then underwent MED (MED group). The 5-year clinical outcomes following the two surgical methods were compared using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire.ResultsThe degree of improvement (DOI) for social life function was significantly greater in the MED group than in the FU group. Although not statistically significant, DOIs for the other four functional scores were also greater in the MED group than in the FU group. However, patients with a large percentage of slippage in the neutral position might experience limited improvement in low back pain, those with a large percentage of slippage at maximal extension might experience limited improvement in three functional scores, and those with a small intervertebral angle at maximal flexion might have limited improvement in three functional scores after MED for DLS. Therefore, we statistically compared the DOIs between the FU and MED groups regarding the preoperative percentage of slippage in the neutral position among patients with greater than 20% slippage, the preoperative percentage of slippage at maximal extension among patients with greater than 15% slippage, and the intervertebral angle at flexion among patients with angles lesser than −5°; however, there were no statistically significant differences between the two groups.ConclusionsMED is a useful minimally invasive surgical procedure that possibly offers better clinical outcomes than FU for DLS

Identification of Carnitine Transporter CT1 Binding Protein Lin-7 in Nervous System

_L-Carnitine is an essential component of mitochondrial fatty acid b-oxidation in the muscle and may control the acetyl moiety levels in the brain for acetylcholine synthesis. Carnitine transporter 1(CT1)is the high affinity _L-carnitine transporter whose localization was observed in the kidney, testis, liver, skeletal muscle and brain. To clarify the molecular mechanism of carnitine transport, we sought to find the interacting protein that may be related to the transport function of CT1. Using the intracellular C-terminal region of rat CT1 containing PDZ(PSD95/DLG/ZO-1)motif as bait, we performed the yeast two-hybrid screening against rat brain cDNA library. Thirty two positive clones were obtained from the 2.7×10^7 clones screened. One of them was PDZ domain-containing protein Lin-7. We found that Lin-7 interacts specifically with C-termini of CT1:deletion and mutation of the CT1 C-terminal PDZ-motif abolished the interaction with Lin-7 in the yeast two-hybrid assay. In addition, a PDZ domain within Lin-7 associates with the CT1 C-terminal. The association of CT1 with Lin-7 enhanced _L-carnitine transport activities in HEK293 cells although there is no statistical significance. Coexpression of Lin-7 and CT1 is identified in motor neurons of the spinal cord ventral horn together with Lin-2, a binding partner of Lin-7 known to assemble proteins involved in synaptic vesicle exocytosis and synaptic junctions. Therefore, Lin-7 interacts with CT1 and may regulate their subcellular distribution or function in central nervous system

ルイスサン ト タイ アニオン ノ セッケイ ニ ヨル リッタイ トクイテキ オヨビ イチ センタクテキ カチオン ジュウゴウケイ ノ カイハツ

京都大学0048新制・課程博士博士(工学)甲第9097号工博第2073号新制||工||1215(附属図書館)UT51-2001-G817京都大学大学院工学研究科高分子化学専攻(主査)教授 澤本 光男, 教授 増田 俊夫, 教授 中條 善樹学位規則第4条第1項該当Doctor of EngineeringKyoto UniversityDFA

A strategy for sequence control in vinyl polymers via iterative controlled radical cyclization.

高分子のモノマー配列を制御する手法の開発. 京都大学プレスリリース. 2016-03-23.There is a growing interest in sequence-controlled polymers toward advanced functional materials. However, control of side-chain order for vinyl polymers has been lacking feasibility in the field of polymer synthesis because of the inherent feature of chain-growth propagation. Here we show a general and versatile strategy to control sequence in vinyl polymers through iterative radical cyclization with orthogonally cleavable and renewable bonds. The proposed methodology employs a repetitive and iterative intramolecular cyclization via a radical intermediate in a one-time template with a radical-generating site at one end and an alkene end at the other, each of which is connected to a linker via independently cleavable and renewable bonds. The unique design specifically allowed control of radical addition reaction although inherent chain-growth intermediate (radical species) was used, as well as the iterative cycle and functionalization for resultant side chains, to lead to sequence-controlled vinyl polymers (or oligomers)