检索结果-南通市图书馆

Effect of Chain Extender on Hydrogen Bond and Microphase Structure of Biodegradable Thermoplastic Polyurethanes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2018年第4期36卷 514-520页

作者： Wen-Kai liu Yun Zhao Rong Wang Feng Luo Jian-Shu li jie-hua li Hong Tan College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University

Thermomechanical properties of polyurethanes（PUs） strongly depend on the molecular interactions and microphase structure. In this work, two chain extenders with different ratios, flexile 1,4-butanediol（BDO） and branched trimethylolpropane mono allyl ether（TMPAE）, are used to tune the molecular interactions and microphase structures of a series of biodegradable thermoplastic polyurethanes（TPUs）. In TPUs, the biodegradable polycaprolactone（PCL, M_n of 2000） is used as soft segment while 1,6-diisocyanatohexane（HDI） and chain extenders are used as hard segment. Fourier transform infrared spectroscopy（FTIR）, proton nuclear magnetic resonance spectroscppy（~1 H-NMR）, gel permeation chromatography（GPC）, differential scanning calorimetry（DSC）, dynamic mechanical analysis（DMA） and mechanical tests were performed to characterize the bulk structure and properties of TPUs. Compared with BDO, the steric bulk of TMPAE is larger. The increment of TMPAE can help to increase the hydrogen bond content, microphase separation, and the elastic modulus ratio（R）, which would strongly affect the thermomechanical property of the TPUs. The results of this work verify the importance of the structure of chain extender on the properties of TPUs. It provides valuable information for further understanding the structure-property relationships of these polyurethanes.

关键词： Chain extender Hydrogen bond Crystallinity Polyurethane

Smith Prediction Monitor AGC System Based on Fuzzy Self-Tuning PID Control

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2010年第2期17卷 22-26页

作者： SUN jie ZHANG Dian-hua li Xu ZHANG Jin DU De-shun State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

In accordance with the feature of pure delay in monitor AGC system for cold rolling mill, a new fuzzy selftuning PID Smith prediction controller is developed. The position control model is deduced based on a single stand cold rolling mill, and the fuzzy controller for monitor AGC system is designed. The analysis of dynamic performance for traditional PID Smith prediction controller and fuzzy self-tuning PID Smith prediction controller is done by MAT- LAB toolbox. The simulation results show that fuzzy self-tuning PID Smith controller has stronger robustness, faster response and higher static accuracy than traditional PID Smith controller.

关键词： monitor AGC fuzzy self-tuning PID control Smith predictor position control

Effect of Fluorocarbon Side Chain on the Microphase Morphology and Rheological Behavior of Thermoplastic Polyurethanes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2023年第6期41卷 933-941,I0009页

作者： Ao Wang Shu-Ren Shao He-Cheng Wu Chen-Xu Tian Feng Luo jie-hua li Zhen li Hong Tan College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China

Fluorinated diols(FDO)with dangling chain were introduced into polyether urethanes(PEUs)as chain extender in order to achieve internal *** on temperature dependent Fourier transform infrared(FTIR)spectroscopy results,the fluorinated polyether urethanes(FPEUs)exhibited weaker hydrogen bonding between C=O and N―H groups with addition of *** crystallinity of hard domain was destroyed determined by thermal *** with the results of dynamic mechanical analysis(DMA)and dissipative particle dynamics(DPD)simulation,it was proved that more loosely aggregated hard domains with weakened interaction separated from soft segment were *** analysis indicated that FDO reduced the complex viscosity and viscous flow activation energy which endowed the polymer with more *** the loss of hydrogen bonds,there was no significant decline in mechanical property resulting from the decrease of hard segment dissolved in soft segment *** presence of fluorinated carbon side chain could function as internal plasticizer and contribute to the processability of polyurethane.

关键词： carbon bonds destroyed

Synthesis and Antimicrobial Properties of the Novel Fluonnated Bis-ammonium Salts with Two Primary Amine Groups

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2006年第11期17卷 1423-1426页

作者： Jian Bin LUO Qiang WANG Hong TAN jie hua li Yin Ping ZHONG College of Polymer Science and Engineering Sichuan University Chengdu 610065 College of Chemistry ＆ Environment ProteCtion Engineering Southwest University for Nationalities Chengdu 610041 Key Laboratory of Bio-resources and Eco-environment （Ministry of Education） College of Life Sciences Sichuan University Chengdu 610064

In order to resolve the increasing resistance phenomena of the Gram-negative bacteria against single chain quaternary ammonium salts （QAS）, lysine with a pedant fluorinated bis-ammonium salts was synthesized and its antimicrobial properties were evaluated in this work. The novel fluorinated bis-ammonium salts shows similar activity with conventional single chain quaternary ammonium salts against Gram-positive bacteria but stronger activity against Gram-negative bacteria and yeast compared with the single chained counterpart.

关键词： Antimicrobial agents fluorinated bis-ammonium salts primary amine groups.

Influence of Hydrogen Bonding on the Temperature-Accelerated Hydrolysis of Silicone Based Polyetherurethane

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2023年第8期41卷 1230-1237,I0007页

作者： He-Cheng Wu Shu-Ren Shao Shuo-Hong Dong Ao Wang Zhen li Xiang-Long Han Feng Luo jie-hua li Dai-Guo Zhao Wan-ling Lan Hong Tan College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringMed-X Center for MaterialsSichuan UniversityChengdu 610065China State Key Laboratory of Oral Diseases National Clinical Research Center for Oral DiseasesWest China Hospital of StomatologySichuan UniversityChengdu 610041China Sichuan Institute for Food and Drug Control Chengdu 611731China

Temperature-accelerated in vitro degradation was established to estimate the longevity of polyurethane applied for long-term ***,the prediction did not correlate well with the data from clinical explants and the rationality of accelerated in vitro test is still in a controversial due to the *** improve the accuracy of the in vitro prediction,the influence of hydrogen bonding(HB)on the accelerated hydrolysis of silicone based polyetherurethans(SPEUs)extended with three side *** the temperature-controlled FTIR and the physical properties after temperature-accelerated in vitro degradation,it was demonstrated that side chain could increase the degree of hydrogen bond dissociation at higher temperature,resulting in the decrease of the calculated activation energy(E_(a))of *** low temperatures,changes in surface morphology and molar mass of PEUs are minimal and HB are less easily dissociated,which had barely impact on the hydrolysis *** was proposed that the E_(a) will not be impacted and that the accuracy of prediction will be increased if the acceleration temperature is lower than 70℃ and HB change is less than 15%.

关键词： Polyether urethane Polydimethylsiloxane Activation energy Hydrogen bonding Hydrolysis resistance

Elaborating Polyurethane Pillowy Soft Mat on Polypropylene Monofilament Surface with Stepwise Surface Treatments

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2022年第11期40卷 1389-1401页

作者： Chen-Xu Tian Tao Zhang Yuan-Qing Song Hao Ming Peng-Qing liu Meng-Jing Jiang Feng Luo jie-hua li Hong Tan Qiang Fu College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu610065China

The dissatisfactory mechanical compliance between stiff polypropylene(PP)and soft human tissue is one of the main factors causing the implanted complication of PP mesh devices such as chronic abdominopelvic pain and mesh *** work aims to improve the mechanical compliance of PP monofilament to human tissue without compromising the mechanical properties by elaborating polyurethane pillowy soft mat on the PP monofilament *** polarity pretreatment with dopamine-sedimentation,stiff PP monofilament can be wrapped up facilely and tightly in soft polyurethane to obtain PU/PP complex fiber with a core-shell ***,the interfacial shear strengths(IFSS)between stepwise treated PP monofilament and PU mat can effectively increase 586%compared to raw *** work provides a promising surface modification strategy to improve the interfacial adhesion between PP monofilament and PU *** obtained novel PU/PP complex fiber with pillowy soft mat would be a potential application in abdominal wall defects,hernia repair and pelvic organ prolapsed surgery.

关键词： Polypropylene monofilament Polyurethane Interfacial adhesion Surface treatment Dopamine-sedimentation

Implantable Polyurethane Scaffolds Loading with PEG-Paclitaxel Conjugates for the Treatment of Glioblastoma Multiforme

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2022年第5期40卷 491-503页

作者： He-Cheng Wu Yuan Feng Xing-Ying Song Chun-Yang Song Jin-lin Chen Yan-Chao Wang Xue-ling He Rui-Chao liang jie-hua li Hong Tan College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China Department of Neurosurgery West China HospitalSichuan UniversityChengdu 610041China Laboratory Animal Center of Sichuan University Chengdu 610041China

Improvement of the treatment for Glioblastoma multiforme(GBM)especially the development of in situ controllable drug release is still a major *** this study,we developed waterborne biodegradable polyurethane(WBPU)scaffolds incorporated with redox-sensitive and RGD-decorated paclitaxel(PTX)polymer-drug conjugates(PDCs)for targeted GBM therapy in *** drug scaffolds could be implanted at residual GBM site ***-targeting PTX-PDCs were obtained through step-by-step conjugation of disulfide linked PTX,poly(ethylene glycol)(PEG),and arginine-glycine-aspartic acid(RGD).The RGD-modified PTX-PDCs were spherical nanoparticles(NPs)that would be released from scaffolds and identified GBM cells *** redox-sensitive PTX-PDCs would be decomposed and release PTX inside GBM cells under the circumstances of glutathione(GSH).The release profiles of PTX from the scaffolds with/without GSH were *** vitro cytotoxicity assay revealed that the dual-targeting PTX-PDCs from scaffolds could specifically kill GBM cells and protect normal cells,suggesting that dual-targeting PTX-PDC-loaded scaffolds may have the potential to repair tumor-induced brain *** vivo anti-recurrence assay indicated that the PTX-PDC-scaffolds could deliver PTX-PDCs to the GBM cells followed by inhibiting tumor growth and inducing *** general,the PTX prodrug-loaded devices exhibited significant anti-GBM effects and normal tissue protection simultaneously,indicating that the WBPU scaffolds incorporated with dual-targeting PTX-PDCs may be a promising strategy for local therapy of GBM.

关键词： GBM PDCs WBPU Scaffolds Controlled release

Anti-oxidation of Tanshinone Ⅱ_A and Prohibitin on Cardiomyocytes

在线全文

学校读者我要写书评

暂无评论

Chinese Herbal Medicines 2010年第3期2卷 204-210页

作者： YANG Ping, JIA Yu-hua, li jie, ZHOU Feng-hua, li li-jun Southern Medical University, Guangzhou 510515, China Southern Medical University Guangzhou 510515China

Objective To investigate the anti-apoptotic mechanism of tanshinone ⅡA and the function of prohibitin (PHB) on myocardial cells apoptosis induced by hydrogen peroxide (H2O2). Methods Myocardial cells were primary cultured neonate rat were cultured in medium with 200 μmol/L H2O2, and the medium was supplemented with tanshinone ⅡA (1 × 10-4 mol/L) in advance for 24 h. PHB in myocardial cells was knocked down by RNA interference, and the expression level of PHB was determined by Western blotting analysis. Flow cytometric analysis was used to detect apoptosis rate, intracellular calcium concentration ([Ca2+]i), and mitochondrial membrane potential (MMP). Results H2O2-mediated cell apoptosis resulted in activation of PHB, increasing of [Ca2+]i, and decreasing of MMP. Tanshinone ⅡA profoundly inhibited myocardial cell apoptosis induced by H2O2, decreased [Ca2+]i, and increased MMP. Specific silence of PHB by siRNA down-regulated the expression level of PHB, increased apoptosis rate and [Ca2+]i, and decreased MMP. Conclusion The results demonstrate that tanshinone ⅡA could attenuate apoptosis induced by H2O2, and the activation of PHB induced by H2O2 is the major regulatory pathway of cyto-protective gene expression against oxidative stress.

关键词： calcium overload myocardial cell oxidative stress prohibitin tanshinone ⅡA

Coronary anomaly： the single coronary artery

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2010年第7期123卷 972-973页

作者： QIN Xu-guang XIONG Wei-guo LU Chun-peng GONG Cheng-jie SHANG li-hua Department of Cardiology First Affiliated Hospital of Tsinghua University Beijing 100016 China

Single coronary artery （SCA）, defined as an artery that arises from the arterial trunk and nourishes the entire myocardium, is rare. We report two cases of SCA, one is the fight coronary artery （RCA） originating from the middle of left descending artery （LAD）, and the other is the left main coronary artery （LMCA） arising from the proximal fight coronary artery.

关键词： coronary anomaly single coronary artery coronary angiography percutaneous coronary intervention