Swelling Behavior of Polybutadiene Networks in Nematic Liquid Crystal Solvents (STATES AND STRUCTURES-Polymer Condensed States) .

Degree of equilibrium swelling (Q) of polybutadiene networks in four nematic liquid crystals (LCs) has been investigated as a function of temperature by cross-polarized microscopy. Phase behavior of the LCs in the networks has also been observed. It has been found that the nematic-to-isotropic phase transition temperatures of the LCs in the networks (TNI g) are slightly (ca. 1K) lower than the ones of the corresponding pure LCs (TNI o), and that the depression degrees of TNI in each system are comparable in spite of large differences in Q between every system. In the temperature regions of TNI g<T<TNI o where the LC phases inside and outside gel are different, Q is almost constant against temperature change

Effects of addition of hindered phenol compounds to a segmented polyurethane with shape memory on mechanical yielding

金沢大学理工研究域自然システム学系金沢大学大学院自然科学研究科The mechanical yielding behavior of the shape memory polyurethane (SMP) and its composite samples were investigated to verify the effect of addition of hindered phenol. The composite samples were prepared using SMP as matrix and hindered phenol (AO-80) as filler, and then tensile tests were carried out at a range of temperatures and with different fixed crosshead speeds. According to the tensile data at 25 °C, the yield stress was increased by adding AO-80. In terms of the Eyring theory, the activation volume of deformation units decreased with increase of the amount of AO-80 added. This is because the packing of the hard segments is enhanced by addition of AO-80. Consequently, it was suggested that the yield process is caused by the rotation of hard segment domains within the deformed plastic domains composed of glassy soft segments. © 2010 Springer Science+Business Media, LLC

Nitinol stenting improves primary patency of the superficial femoral artery after percutaneous transluminal angioplasty in hemodialysis patients: A propensity-matched analysis

BackgroundAlthough percutaneous transluminal angioplasty (PTA) has become a common therapeutic standard for peripheral artery disease (PAD), high restenosis rates in the superficial femoral artery (SFA) remain a major problem. Nitinol stent implantation is reported to reduce restenosis in SFA after PTA in the general population; however, little is known about whether the nitinol stent improves primary patency after PTA in hemodialysis patients who are at higher risk of revascularization failure. The aim of this study was to clarify the effects of nitinol stent implantation for primary patency in SFA after PTA in hemodialysis patients with PAD.MethodsEighty consecutive hemodialysis patients (167 SFA lesions) who underwent PTA with nitinol stents from January 2006 to January 2008 were compared with 64 hemodialysis patients (128 SFA lesions) who received stainless steel stents in the preceding 2 years. In the follow-up study to 2 years, incidence of restenosis, amputation, and all-cause mortality were analyzed. End points between the groups were examined with the Kaplan-Meier and log-rank methods. Prognostic values for end points were calculated by a Cox univariate analysis and Cox multivariable regression models. To statistically minimize the differences in each stent group, a propensity-matched analysis was also performed using the model including male gender, age, diabetes, hypertension, hyperlipidemia, smoking, incidence of ulcer/gangrene, and TransAtlantic Inter-Society Consensus (TASC) type C+D.ResultsThe 2-year primary patency rate was 58% in the nitinol group vs 42% in the stainless steel group (hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.39-0.84; P = .0045), despite a higher prevalence of TASC C+D lesion in the nitinol group (68% vs 49%, P = .0014). In 108 lesions matched after propensity score analysis, the primary patency for 2 years was 64% in the nitinol group vs 42% in the stainless steel group (HR, 0.39; 95% CI, 0.24-0.65; P = .0003). Cox multivariate models showed nitinol stent (HR, 0.42; 95% CI, 0.25-0.73; P = .002), age (HR, 1.04; 95% CI, 1.01-1.08; P = .031), and incidence of ulcer/gangrene (HR, 2.35; 95% CI, 1.17-4.75; P = .017) were independent predictors of restenosis.ConclusionThese data suggest that nitinol stent implantation improves primary patency in SFA after PTA compared with the stainless steel stent, even in hemodialysis patients with PAD

Development and External Validation of a Nomogram Predicting the Probability of Significant Gleason Sum Upgrading among Japanese Patients with Localized Prostate Cancer

Objective. The aim of this study is to develop a prognostic model capable of predicting the probability of significant upgrading among Japanese patients. Methods. The study cohort comprised 508 men treated with RP, with available prostate-specific antigen levels, biopsy, and RP Gleason sum values. Clinical and pathological data from 258 patients were obtained from another Japanese institution for validation. Results. Significant Gleason sum upgrading was recorded in 92 patients (18.1%) at RP. The accuracy of the nomogram predicting the probability of significant Gleason sum upgrading between biopsy and RP specimens was 88.9%. Overall AUC was 0.872 when applied to the validation data set. Nomogram predictions of significant upgrading were within 7.5% of an ideal nomogram. Conclusions. Nearly one-fifth of Japanese patients with prostate cancer will be significantly upgraded. Our nomogram seems to provide considerably accurate predictions regardless of minor variations in pathological assessment when applied to Japanese patient populations

マッタン カキョウ コウブンシ アミメ ノ コウゾウ オヨビ ブツリ カガク トクセイ ニ カンスル ケンキュウ

京都大学0048新制・課程博士博士(工学)甲第8969号工博第2060号新制||工||1208(附属図書館)UT51-2001-F299京都大学大学院工学研究科高分子化学専攻(主査)教授 粷谷 信三, 教授 田中 文彦, 教授 升田 利史郎学位規則第4条第1項該当Doctor of EngineeringKyoto UniversityDA

高分子フィルムの逐次二軸変形過程における分子配向挙動の解明

金沢大学理工研究域自然システム学系本研究では自作の測定装置を用いて二軸延伸過程中における複屈折測定法を確立した。二軸延伸過程中の複屈折測定により以下のことがわかった。・aPPは等二軸、逐次二軸延伸過程において弾性的に変形し、最終的な配向状態は見かけ上等しくなることがわかった。・iPPは150℃下における等二軸、逐次二軸延伸過程において塑性的に変形し、最終的な配向状態は大きく異なることがわかった。研究課題/領域番号:19750179, 研究期間(年度):2007 – 2008出典：「高分子フィルムの逐次二軸変形過程における分子配向挙動の解明」研究成果報告書　課題番号19750179（KAKEN：科学研究費助成事業データベース（国立情報学研究所））（https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-19750179/19750179seika/)を加工して作

溶融エレクトロスピニング法による新規ナノファイバーの調製法の確立とその物性評価

金沢大学理工研究域自然システム学系本研究では、溶融エレクトロスピニング法によるイソタクチックポリプロピレン(iPP)ナノファイバーの調製、および物性評価を目的とし、様々な紡糸条件や、試料で紡糸を行い、これらがファイバー径に与える影響について検討した。また、このようにして得られたファイバーの物性を評価するために、DSC測定および引張試験を行った。以下に本研究で得られた結果を示す。・ES法でのiPPナノファイバーの紡糸に成功した。・電場強度が弱いほど、より細いファイバーを多く紡糸することがわかった。・紡糸温度を変化させて実験を行った結果、最適の紡糸温度があることがわかった。・分子量が低いほど、より細いファイバーを紡糸することがわかった。・分子量分布が比較的狭い試料では、ファイバー径分布が狭くなることがわかった。・これらよりファイバー径には、溶融粘度や表面張力が大きく関係していると示唆される。・DSC測定により溶融ES法によって紡糸されたファイバーはメソフェーズ相を持つことがわかった。・引張試験によって得られたヤング率よりファイバーは細いものほど配向し、強度が上昇していることがわかった。We prepared isotactic polypropylene (iPP) nanofibers by melt-electrospinning methods. The effects of spinning conditions such as electric field strength and temperature for various iPP samples with different molecular weights and molecular weight distribution on the thermal behavior and on tensile behavior were investigated. We found followings.The fine fibers with the diameter in the submicron order were successfully prepared by melt-electrospinning methods.The average of the fiber diameter decreased with weakening the electric field strength and with decreasing the molecular weight.The DSC charts of the prepared nanofibers showed the existence of the mesophase structure.The iPP chains in the nanofibers were oriented to the spinning direction, which causes the high mechanical strength with the low strain at break.研究課題/領域番号:21750215, 研究期間(年度):2009-2010出典：研究課題「溶融エレクトロスピニング法による新規ナノファイバーの調製法の確立とその物性評価」課題番号21750215（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-21750215/21750215seika/）を加工して作

Structure-mechanical property correlations of model siloxane elastomers with controlled network topology

AbstractWe review our recent studies towards the molecular understanding of mechanical properties–structure relationships of elastomers using model polydimethylsiloxane (PDMS) networks with controlled topology. The model elastomers with controlled lengths of the network strands and known amounts of cross-links and dangling chains are obtained by end-linking the functionally terminated precursor PDMS with known molecular weights using multi-functional cross-linkers. Several modern entanglement theories of rubber elasticity are assessed in an unambiguous manner on the basis of the nonlinear stress–strain behavior of the model elastomers under general biaxial strains. The roles of cross-links and entanglements in the large-scale structure of the swollen state are revealed from small angle X-ray scattering spectra. A remarkably stretchable elastomer with the ultimate strain over 3000% is obtained by optimizing the network topology for high extensibility, i.e., by reducing the amounts of trapped entanglements and the end-to-end distance of the network strands. The model elastomers with unattached chains exhibit a pronounced viscoelastic relaxation originating from the relaxation by reptative motion of the guest chains. The relaxation spectra provide a definite basis to discuss the dynamics of guest linear chains trapped in fixed polymer networks. The temperature- and frequency-insensitive damping elastomers are made by introducing intentionally many dangling chains into the networks