Effect of Molecular Weight on Thermoelectric Performance of P3HT Analogues with 2-Propoxyethyl Side Chains

By replacing hexyl chains in poly(3-hexylthiophene)(P3HT)with 2-propoxyethyls,four poly(3-(2-propoxyethyl)thiophene)(P3POET)homopolymers with comparable polydispersity indexes(PDI)and regioregularities were prepared herein in addition with step increment of about 7 kDa on numberaverage molecular weight(M_(n))from around 11 to 32 kDa(accordingly denoted as P11k,P18k,P25k,and P32k).When doped in film by FeCl_(3)at the optimized conditions,the maximum power factor(PF_(max))increases greatly from 4.3μW·m^(-1)·K^(-2)for P11k to 8.8μW·m^(-1)·K^(-2)for P18k,and further to 9.7μW·m^(-1)·K^(-2)for P25k,followed by a slight decrease to 9.2μW·m^(-1)·K^(-2)for P32k.The close Seebeck coefficients(S)at PF_(max)are observed in these doped polymer films due to their consistent frontier orbital energy levels and Fermi levels.The main contribution to this PF_(max)evolution thus comes from the corresponding conductivities(σ).Theσvariation of the doped films can be rationally correlated with their microstructure evolution.

Effects of low molecular weight polysaccharide from Sargassum thunbergii against palmitic acid-induced intracellular lipid accumulation in 3T3-L1 adipocyte and HepG2 cells

Low molecular weight polysaccharides can be isolated from Sargassum thunbergii(LMPST)and in vitro experiments were conducted to evaluate the inhibitory effects on lipids.Two natures of LMPST were attained from S.thunbergii and appraised their LMPST on palmitic acid(PA)induced lipid accretion in Hep G2,and 3T3-L1 cells.LMPST treatment lessened lipid deposition and intracellular free fatty acid and triglyceride intensities in PA-treated above mentioned cells.The mechanistic study publicized that LMPST2 significantly suppressed adipogenesis and stimulated the PA-treated 3T3-L1 cells occupied in the lipolysis pathway.Furthermore,in PA-treated Hep G2 cells,the free fatty acid oxidation was significantly increased by LMPST2.Given these constructive properties of LMPST2 from S.thunbergii,is a potential candidate for diminishing the intracellular lipids,and for a therapeutic agent in those conditions.

PREPARATION OF MICROPOROUS ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE (UHMWPE) BY THERMALLY INDUCED PHASE SEPARATION OF A UHMWPE/LIQUID PARAFFIN MIXTURE

Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UHMWPE. Small angle laser light scattering (SALLS) and differential scanning calorimetry (DSC) were used to determine the phase separation temperatures,i.e.the cloud points and the dynamic crystallization temperatures,respectively.It was found that the cloudI points were coincident with the cryst...

Pharmacokinetics of fucoidan and low molecular weight fucoidan from Saccharina japonica after oral administration to mice

The brown seaweed,Sacchairna japonica,has been used in traditional Chinese medicine for over one thousand years.Oral administration of fucoidan or low molecular weight fucoidan(LMWF)from S.japonica could ameliorate kidney dysfunction in chronic kidney diseases and inhibit diabetic vascular complications.In many studies,LMWF was found to be more potent than fucoidan with high molecular weight.However,the pharmacokinetics of LMWF still remains unclear.The purpose of the research is to compare the pharmacokinetics of fucoidan with high molecular weight(136 kDa)with that low molecular weight(9.5 kDa)after oral administration to ICR mice.Since fucose is the main and representative monosaccharide of fucoidans,we evaluate the pharmacokinetics of fucoidan and LMWF by determining the fucose concentration in mice serum.Both fucoidan and LMWF were absorbed following oral administration.Fucoidan and LMWF were provided to mice by oral administration with 60 mg/kg and the maximum Concentration(C_(max))was found at 2.5 h(0.66±0.32 mg/L)for Fucoidan and 1.5 h(1.01±0.56 mg/L)for LMWF,respectively.It seems that LMWF had a higher area under the curve(AUC_(0–t))and was absorbed more quickly than fucoidan.The estimated bioavailability of LMWF was28.3%in the mice treated with a single dose of 30 mg/kg.In addition,LMWF was found widely spreaded into different tissues following oral administration and the highest concentration was found in kidney at 19.93±7.02μg/g.In this study,we first studied the pharmacokinetics of LMWF,in order to help to understand the function of LMWF.And our results shed light on the potential of development of drugs based on LMWF.

Structural characterizations andα-glucosidase inhibitory activities of four Lepidium meyenii polysaccharides with different molecular weights

Four polysaccharides(MCPa,MCPb,MCPc,MCPd)were obtained from Lepidium meyenii Walp.Their structures were characterized by chemical and instrumental methods including total sugar,uronic acid and protein content determi-nation,UV,IR and NMR spectroscopy,as well as monosaccharide composition determination and methylation analy-ses.Four polysaccharides were a group of glucans with different molecular weights ranging from 3.12 to 14.4 kDa,and shared a similar backbone chain consisting of(1→4)-glucose linkages with branches attached to C-3 and C-6.Furthermore,bioactivity assay showed that MCPs had concentration-dependent inhibitory activity onα-glucosidase.MCPb(Mw=10.1 kDa)and MCPc(Mw=5.62 kDa)with moderate molecular weights exhibited higher inhibitory activ-ity compared with MCPa and MCPd.

Purification and immunoglobulin E epitopes identification of low molecular weight glutenin:an allergen in Chinese wheat

As one of the most important cereals,wheat(Triticum aestivum)has high nutritional value and is widely cultivated in China.However,wheat can cause severe allergic reactions,and a growing number of people are developing allergies to Chinese wheat.Low molecular weight glutenin(LMW-GS),an important allergen in susceptible populations,is responsible for celiac disease and wheat contacts dermatitis.In this study,LMW-GS was highly purified from Chinese wheat(Xiaoyan 6)and further identified and characterized.In addition,8 peptides were predicted efficiently by 5 immunological tools,among which 5 peptides showed significant immunoglobulin E binding abilities.Two specific epitopes were found to be in the non-conserved region of the amino acid sequence of LMW-GS,which was speculated to be the specific epitope of Chinese wheat.This systematic research of LMW-GS may provide new insights into the prevention of wheat allergy and development of hypoallergenic wheat products.

Exploring the mechanism of Guizhi decoction’s“Jun-Chen-Zuo-Shi”in treating plant nervous disorders based on weighted network pharmacology and molecular docking techniques

Objective:To explore the mechanism of Guizhi decoction’s“Jun-Chen-Zuo-Shi”in treating plant nervous disorders based on network pharmacology and molecular docking methods.Methods:The main active ingredients of Guizhi decoction were screened from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP),and plant nervous disorder-related targets were screened from the Gene Cards database,OMIM database,and PharmGKB database.The intersection of the two was obtained.The intersection targets were used to draw a protein interaction network and a“Traditional Chinese Medicine-active ingredient-target”network using the STRING database and Cytoscape 3.9.1.The nodes in the“Traditional Chinese Medicine-active ingredient-target”network were weighted according to the“Jun-Chen-Zuo-Shi”principle.Kyoto Encyclopedia of Genes and Genomes,and gene ontology enrichment analysis were performed on the intersection targets.Molecular docking was used to verify the affinity between core targets and key ingredients.Results:A total of 225 effective components of Guizhi decoction were screened,among which 127 components could bind to 160 common targets and play a therapeutic role.The common targets were mainly enriched in 2785 gene ontology entries and 189 Kyoto Encyclopedia of Genes and Genomes pathways.Molecular docking confirmed that core targets could spontaneously bind to key ingredients.Conclusion:The key targets for the treatment of plant nervous disorders by Guizhi decoction are MAPK1,TP53,RB1,STAT3,MAPK3,MAPK14,etc.,which reflect the characteristics of the synergistic mechanism of traditional Chinese medicine with multiple components,targets,and pathways through the regulation of inflammatory signal pathways and oxidative stress processes.

双向同性自增强UHMWPE板材的制备

在室温条件下,对超高分子量聚乙烯(UHMWPE)模压板双向辊压,以实现双向自增强。探究了双向均匀提升模压板性能的技术可行性,考察了辊压比对模压板球晶形变的影响以及自增强板材聚集态结构与其力学性能的关联性。结果表明,辊压使原模压板约71.2 nm的球晶细化至39.4 nm的微晶,结晶度从45.2%降至40.2%,部分正交晶系转变为单斜晶系。辊压比达36.6%的自增强板材,两个方向的拉伸强度分别达到了62、60 MPa。

捻度对渔用UHMWPE裂膜纤维线股拉伸性能与耐磨性能的影响研究

为促进超高分子量聚乙烯裂膜纤维(简称UHMWPE裂膜纤维)在渔用绳网中的应用,以膜裂法制备渔用UHMWPE裂膜纤维为原料,通过加捻制备渔用UHMWPE裂膜纤维线股,在此基础上,考察了加捻对UHMWPE裂膜线股的线密度、直径、拉伸性能和耐磨性能的影响。结果显示:UHMWPE裂膜纤维线股随捻度的增加表现出直径逐渐减小、实际线密度先增大后减小以及捻回角逐渐增加等特征;对于不同线密度规格的UHMWPE裂膜纤维线股,随着捻度的增加,其断裂强力均呈现降低的趋势,且纤维线密度越低,加捻对线股断裂强度的影响越小;1600 D的UHMWPE裂膜纤维线股的磨损次数随捻度的增加而降低,而3200和4800 D线股的磨损次数随捻度的增加呈现先降低后升高的变化趋势,且4800 D的不同捻度的线股之间的磨损次数无显著性差异(P<0.05),显示出纤维线密度越大,加捻对其耐磨性能的影响越小。1600、3200和4800 D的UHMWPE裂膜纤维线股的结节强力随捻度的增大呈现先升高后降低的变化趋势,当预加捻度为120 T·m^(-1)时,3种线密度线股的结节强力达到最大值,分别为204.15、373.5、562.41 N,较未加捻UHMWPE裂膜纤维分别提高了50.14%、37.13%和30.22%。在本实验捻度设置范围内,1600 D裂膜线股的结节强度随捻度的增加而增大,较未加捻裂膜纤维结节强度提高了32.49%。研究表明,无捻或低捻度、低线密度UHMWPE裂膜纤维线股可用于UHMWPE裂膜纤维无结网的制备;无捻或低捻度的高线密度UHMWPE裂膜纤维线股则具有较好的耐磨性能;中高捻度、低线密度UHMWPE裂膜纤维线股可用于UHMWPE裂膜纤维有结网的制备。研究结果可为渔用UHMWPE裂膜纤维绳网材料的加工、开发与应用提供参考。

Ballistic Penetration Damage of Hybrid Thermoplastic Composites Reinforced with Kevlar and UHMWPE Fabrics

Polymer matrix types of fiber hybrid composites are key factors to improve ballistic impact damage tolerances.Here we report ballistic penetration damages of Kevlar/ultra-high molecular weight polyethylene(UHMWPE)hybrid composites with thermoplastic polyurethane(PU)matrix.The hybrid composites were penetrated by fragment-simulating projectiles(FSPs)using an air gun impact system.The effects of stacking sequences on the ballistic performance of hybrid composites were analyzed.Two types of specific energy absorption(the energy absorption per unit area density and the energy absorption per unit thickness)were investigated.It was found that the main damage modes of PU hybrid composites were fiber breakage,matrix damage,fiber pullout and interlayer delamination.The instantaneous deformation could not be used as a reference index for evaluating the ballistic performance of the target plate.The energy absorption process of the PU hybrid composites showed a nonlinear pattern.The hybrid structure affected the specific energy absorption of the materials.

Preparation of high molecular weight （HMW） genomic DNA from tea plant （Camellia sinensis） for BAC library construction

A bacterial artificial chromosome （BAC） library is an invaluable resource tool to initiate tea plant genomics research, and the preparation of high molecular weight （HMW） genomic DNA is a crucial first step for constructing a BAC Library. In order to construct a BAC library for enhancing tea plant genomics research, a new method for the preparation of tea pant high molecular weight （HMW） genomic DNA must be developed due to young tea plant leaves and shoots are notably rich in both tea polyphenols and tea polysaccharides. In this paper, a modified method for preparing high quality tea plant HMW genomi~ DNA was optimized, and the quality of tea plant genomic DNA was evaluated. The results were as follows： Critical indicators of HMW DNA preparation were the appearance of the smooth nuclei in solution （as opposed to sticky-gummy） before agarose plug solidification, non-dark colored nuclei plugs after lysis with an SDS/proteinase K solution, and the quality and quantity of HMW DNA fragments after restriction enzyme digestion. Importantly, 1% dissolved PVP-40 and 1% un-dissolved PVP-40 during the nuclei extraction steps, in conjunction with the removal of PVP-40 from the plug washing and nuclei lysis steps, were critical for achieving HWM tea plant DNA suitable for BAC library construction. Additionally, a third PFGE fraction selection step to eliminate contaminating small DNA fragments. The modifications provided parameters that may have prevented deleterious interactions from tea polyphenols and tea polysaccharides. The HMW genomic DNA produced by this new modified method has been used to successfully construct a large-insert tea plant BAC library, and thus may be suitable for BAC library construction from other plant species that contain similarly interfering compounds.

Ion Radiation Detection Using Implanted Ultrahigh Molecular Weight Polyethylene Structures (UHMWPE)

The effect of ion implantation, including Ar+ ion with influences (1 × 1013 - 1015 ions/cm2), on the electrical and optical properties of ultrahigh molecular weight polyethylene (UHMWPE) were investigated with particular emphasis placed on the sensor performance to be used in the field of radiation detection. The obtained results focusing on the effect of the different influences showed a significant change in the electrical conductivity, capacitance and loss tangent. The absorption spectra for UHMWPE samples were recorded and the values of the allowed direct and indirect optical energy gap (Eopt)d, (Eopt)in of UHMWPE and energies of the localized states for the virgin and implanted samples were calculated. We found that the optical energy gap values decreased as the radiation dose increased. The results can be explained on the basis of the ion beam radiation-induced damage in the linear chains of UHMWPE, with cross-linking generated after implantation. The observed changes in both the optical and the electrical properties suggest that the UHMWPE film may be considered as an effective material to achieve ion-radiation detection at room temperature.

牵伸倍数对PE-UHMW膜材料性能的影响

高性能纤维增强树脂基复合材料的发展促进了防弹装备的发展,在面对高能杀伤武器威胁加剧和单兵携行负荷增加的情况下,防护装备高防护、轻量化的需求日益迫切,超高分子量聚乙烯(PE-UHMW)膜材料的出现,有助于满足轻质高防的需求。PE-UHMW条带作为PE-UHMW膜材料的最小组成,对膜材料性能的影响决定防弹装备的性能。为探究不同牵伸倍数对膜材料性能的影响,选取由不同牵伸倍数条带制备的膜材料开展理化特性、力学性能和防弹性能研究。测试分析发现,PE-UHMW膜材料在分子量、结晶度、取向度等理化特性的不同使层压得到的复合材料力学性能有所差异,进而在不同弹击条件下防弹性能呈现出差异化特点。由高倍牵伸条带制备的膜材料分子量达到5 658 000 g/mol,由其制备的复合材料具有更加优异的力学性能,弯曲强度为102.12 MPa,弯曲弹性模量为23.30GPa,剪切强度为8.60 MPa,经过层压制备的8 kg/m^(2)面密度靶板在常温条件下防1.1 g标准模拟破片V50值达到了804.50 m/s,51式7.62 mm手枪弹弹着点弹痕高度为13.20 mm。在树脂体系与加工工艺一致的情况下,由高牵伸倍数PE-UHMW条带制备的PE-UHMW膜材料在力学和防弹性能方面具有明显优势,具备在个体防护领域的应用潜力。

单宁酸表面改性PE-UHMW纤维及其界面性能研究

使用单宁酸(TA)对超高分子量聚乙烯(PE-UHMW)纤维进行表面改性,研究了金属离子种类及反应时间对单宁酸与金属离子(TA-[M])改性对PE-UHMW纤维性能的影响,并在TA-[M]改性溶液中引入聚乙烯亚胺(PEI),研究了PEI分子量对TA-[M]-PEI改性PE-UHMW纤维性能影响,以及PEI对TA涂层稳定性的影响。结果表明,TA涂层成功涂覆在PE-UHMW纤维表面,在纤维表面引入了羟基官能团。TA-Fe改性12 h后纤维与环氧树脂(EP)的界面剪切强度较改性前提高了102.03%;与聚氨酯树脂(PU)界面剪切强度提升了97.78%。TA-Fe改性12 h后纤维与PU的界面粘接强度提高了44.35%;与EP的界面粘接强度提高了58.50%。氨基化合物PEI能够改善TA涂层的稳定性,超声清洗实验后PE@TA-Fe-PEI600比PE@TA-Fe界面黏结强度下降少。

乙烯-丙烯酸共聚物改性环氧树脂/UHMWPE纤维复合材料的制备与性能研究

使用乙烯-丙烯酸共聚物(EAA)与环氧树脂复配作为基体,利用水基乳液浸渍超高分子量聚乙烯(UHMWPE)纤维制备了复合材料,通过在树脂浸润性、树脂耐热性能、复合材料力学性能、界面结合情况以及微观形貌等方面的测试表征,对比了不同EAA含量的基体树脂对UHMWPE纤维复合材料性能的影响。结果表明,EAA与环氧树脂质量比为25∶75的共混体系一方面可发挥EAA组分与UHMWPE纤维间亲和力强的优势,另一方面还能凭借环氧树脂的刚性交联网络保持较高的耐热性能,体系的层间剪切强度达到8.7 MPa,在60℃下弯曲强度保持率接近80%,表现出优异的综合性能。

碳化硼陶瓷/UHMWPE纤维复合靶板防弹性能仿真与实弹验证

目的:为实现防弹靶板的轻量化和高防护性,对碳化硼陶瓷/超高分子量聚乙烯(ultra-high molecular weight polyethylene,UHMWPE)纤维复合靶板的防弹性能进行仿真优化与实弹验证。方法:首先,基于ANSYS/LS-DYNA建立碳化硼陶瓷/UHMWPE纤维复合靶板的有限元模型。其次,对子弹侵彻不同厚度搭配的防弹靶板过程进行仿真,分析防弹靶板对100 m处56式7.62 mm普通枪弹的防护效果。最后,基于仿真结果,以靶板的防护性和质量作为主要指标,对靶板进行优化设计,并通过实弹射击验证设计靶板的防弹性能。结果:仿真结果表明,不同厚度搭配的防弹靶板都可以实现对100 m处56式7.62 mm普通枪弹的有效防护;实弹验证结果表明,仿真结果准确,设计的防弹靶板具有较好的防护性。结论:对碳化硼陶瓷和UHMWPE纤维设置合理的配比可以满足防弹靶板的高防护性和轻量化需求,该研究可为轻质、高防护性防弹靶板的研发提供参考。

影响UHMWPE原料溶胀性能因素的初步探讨

通过单因素条件对超高分子质量聚乙烯树脂与白油混合液溶胀行为进行了研究,探讨了不同溶胀时间、溶胀温度、质量分数,以及超声波处理时间等对其溶胀性能的影响。并通过其混合液黏度、溶胀度的测试,得出国内外四种不同供应厂家、分子质量在400万左右的超高分子质量聚乙烯原料在不同溶胀工艺条件下的影响结果,为车间溶胀工艺提供一定的理论参考。

Numerical simulation of effects of operating conditions on the molecular weight of polypropylene using a response surface method

A L463^5 Box-Behnken design was used for developing a model to predict and optimize the molecular weight （Mw ） of polypropylene （PP） ; a second-order polynomial regression equation was derived to predict responses. The significance of variables and their interactions were tested by means of the ANOVA with 95% confidence limits; the standardized effects were investigated by Pareto chart, the optimum values of the selected variables were obtained by analyzing the response surface contour plots. The optimized Mw value of 1. 217 × 10^5 g/mol was very close to the industrial value （ （ 1.22 ±0. 004） ×10^6 g/tool） at the optimum values.

Analysis of Molecular Weight Distribution and Antioxidant Activities of Cirrhinus molitorella Skin Collagen Hydrolysates

[Objective] The aim of this work was to identify molecular weight （MW） distribution and antioxidant activity of fish skin col agen hydrolysates. [Method] The MW distribution of hydrolysates was determined using both size exclusion chromatography and matrix-assisted laser desorption ionization time-of-flight mass spec-trometry （MALDI-TOF-MS）. Fish skin were treated by the alkaline protease 2709. [Result] The optional conditions for hyerolysis were time 3 h, temperature 55 ℃, pH 10.0, substrate concentration 80 g/L and E/S 4%. The results of both methods indi-cated that the molecular weight of col agen hydrolysates was from 400 to 1 800 Da, and the peptides’ molecular weight was less than 1 400 Da mostly. The reducing power and antioxidant/radical scavenging activity [1, 1-diphenyl-2-picryl-hydrazyl （DPPH） free radical scavenging activity] were determined. [Conclusion] The results reveal that the fishskin hydrolysate is a potential source of antioxidants.

UHMWPE模压成型方法与技术进展

目前,性能较好的超高分子量聚乙烯(UHMWPE)制品得到了广泛应用,但是,由于UHMWPE的黏度较高,难以输送、塑化和成型。模压成型是UHMWPE制品最主要的成型方式之一。首先,对最常用的普通静态模压(CM)成型方法进行陈述,分析并总结了成型温度、成型周期、成型压力以及冷却速率等模压成型参数对CM成型UHMWPE制品微观结构和性能的影响,发现,CM成型存在成型周期长、能耗高以及制品难以兼具良好的力学强度和耐磨性能等问题;其次,阐述了UHMWPE高速冲击(HVC)模压和超声模压的成型原理和特点,发现,引入动态力场后,能降低成型温度、缩短成型周期和减少能耗,但是,由于HVC成型UHMWPE制品韧性较差,超声模压成型制品力学强度较低。因此,动态模压成型方法是UHMWPE制品高效成型的重要研究方向之一。