纳米SiO2填充LLDPE复合材料耐热性的研究

采用DSC方法研究了纳米二氧化硅(SiO2)填充线性低密度聚乙烯(LLDPE)的熔融特性。结果表明：填充LLDPE的高温熔融峰峰值温度Tm2变化不大，低温熔融峰温Tml则随着纳米SiO2用量的增加明显向低温偏移，显示出纳米粒子的异相成核作用；在纳米SiO2用量相同的情况下，与表面未处理SiO2及经表面偶联剂处理纳米SiO2填充体系相比较，加有大分子相容剂的体系的Tml和Tm2均有所下降，同时熔融峰宽化；填充LLDPE的热变形温度HDT和软化温度Tg均随纳米SiO2用量的增加而提高；与表面未处理填充体系相比，硅烷偶联剂处理纳米SiO2填充体系的HDT有所上升，加有大分子相容剂的体系的HDT上升则更为明显。     

急性冠状动脉综合征患者血清中基质金属蛋白酶-2的表达

目的探讨急性冠状动脉综合征与血清基质金属蛋白酶-2(MMP-2)的相关性。方法应用酶图(SDS-PAGE en-zymograph)和Western blot方法检测50名急性冠脉综合征患者(27名ST段抬高急性心肌梗塞患者和23名不稳定性心绞痛患者)、20名稳定性心绞痛患者及40名正常对照者的血清MMP-2水平。结果急性心肌梗塞组血清MMP-2水平明显高于不稳定性心绞痛组;急性心肌梗塞组及不稳定性心绞痛组血清MMP-2水平明显高于正常对照组;稳定性心绞痛组与正常对照组差异无显著意义;急性心肌梗塞组及不稳定性心绞痛组血清MMP-2水平高于稳定性心绞痛组。结论急性冠脉综合征患者血清MMP-2水平明显升高,其水平可能与冠状动脉斑块的稳定性相关。     

Intimin及其受体Tir在致病性大肠杆菌致细胞线粒体功能障碍中的作用

目的探讨致病性大肠杆菌(Enteropathogenic Escherichia coli,EPEC)外膜蛋白Intimin及其受体Tir在EPEC致HeLa细胞线粒体功能障碍中的作用。方法将EPEC外膜蛋白Intimin及其受体Tir删除株、相应质粒互补株或染色体互补株感染HeLa细胞,用线粒体膜电位(Mitochondria membrane potential,MMP)检测试剂JC-1染色细胞线粒体,通过多功能酶标仪检测MMP水平,Western blot检测Intimin的表达及Tir的转位。结果与野生型菌株相比,Eae删除株和Tir删除株感染细胞的MMP功能显著减弱(P<0.05),Eae删除株功能能被质粒表达相应蛋白所互补,Tir删除株不能被质粒表达Tir互补,但可被染色质表达野生型Tir或TirY474S互补,而染色质TirS434A突变株不能引起明显的MMP下降。结论 Intimin和Tir是参与线粒体功能障碍的重要分子;TirS434在线粒体功能障碍中起重要作用。     

玻璃纤维增强酚醛摩阻材料

针对玻璃纤维增强酚醛摩阻材料存在的问题，研究分析了不同类型玻纤维增强酚醛树脂、玻纤增强橡胶改性酚醛树脂、下纤增强三聚氰胺腰果壳油改性酚醛树以及混杂纤维增强酚醛树脂摩阻材料的性能，并对摩阻复合材料的发展提出建议。     

三七叶甙制备原人参二醇及其差向异构体

三七叶总甙以c(NaOH)=2mol/L的氢氧化钠水溶液溶解,沸水浴加热8h进行水解,所得产物经乙酸乙酯萃取和硅胶柱层析分离得到原人参二醇。三七叶总甙与浓盐酸常温反应7h后,再用饱和碳酸钠溶液常温搅拌24h,所得产物经乙酸乙酯萃取和硅胶柱层析分离得到20(R) 原人参二醇。它们的结构经光谱分析及与文献对照得以鉴定。     

Electromechanical behavior of hybrid carbon/glass fiber composites with tension and bending

To understand the smart (i.e., good memory) characteristics of hybrid composites of carbon fibers (CFs) and glass fibers (GFs) with epoxy resin as a matrix, the changes in the electrical resistance of composites with tension and on bending were investigated. The electrical resistance behavior of composites under tension changed with the composition of the CF/GF, as well as with the applied strain. The fractional electrical resistance increased slowly with increasing strain within a relatively low strain region. However, with further loading it increased stepwise with the strain according to the fracture of the CF layers. The strain sensitivity of the samples increased with increasing CF weight percentage, and the samples incorporating more than 40 wt % CF showed a strain sensitivity higher than 1.54 for a single CF. The changes in the fractional electrical resistance with bending were not so dominant as those with tension. This difference was attributed to the action of two cancelling effects, which are the increasing and decreasing fractional electrical resistance due to tension and compression with bending, respectively. On recovery from a large applied bending, the fractional electrical resistance decreased slowly with unloading because of the increase of contacts between the fibers that resulted from the reorganization of ruptured CFs during the recovery. Even the composites incorporating a relatively small CF content showed an irreversible electrical resistance with both tension and bending. However, the strain sensitivity being larger with tension than with bending is ascribed to the difference in their mechanical behaviors. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2447–2453, 2002     

白炭黑补强溴化丁基橡胶的性能及特点

研究了白炭黑补强溴化丁基橡胶（BIIR）的性能及特点。结果表明；与炭黑补强相比，白炭黑补强的BIIR表现出了良好的工艺性能、力学性能和热老化性能；硅烷偶联剂（Si69）用置对硫化胶的力学性能有很大的影响；同时还发现白炭黑补强BIIR的拉伸应力软化效应和应力松驰性能与炭黑补强BIIR有着明显的区别。     

Polyamide 66 nanocomposites based on organoclays treated with thermally stable phosphonium salts

Purification of bentonite clays and their modification with two thermally stable (alkyl and aryl) phosphonium organic salts were investigated. The organoclays were subsequently melt compounded with Polyamide 66 (PA66), with and without the use of an elastomeric compatibilizer. The morphology, melt flow, thermal stability, and mechanical properties of the binary and ternary nanocomposites were studied. The bentonite clay was purified by sedimentation, resulting in higher cation exchange capacity and thermal stability in comparison with unpurified clay. These were then used in the synthesis of two thermally stable organoclays by replacing the interlayer sodium cations with two (alkyl and aryl) phosphonium surfactant cations to circumvent the problem of low temperature decomposition of quaternary ammonium organoclays usually used in polymer nanocomposites. The organoclay with aliphatic groups showed more compatibility with PA66 in comparison with the organoclay with aromatic groups. Thus, the use of organoclay with aliphatic groups resulted in nanocomposites with higher tensile strength, higher modulus, higher elongation at break, and higher impact strength in comparison with the nanocomposites produced from the organoclay with aromatic groups. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

UP/纳米CaCO3复合材料体积收缩性能的研究

研究了纳米CaCO3对不饱和聚酯树脂(UP)体积收缩性能的影响及其作用机理.结果表明,随着纳米CaCO3用量的增加,UP/纳米CaCO3复合材料的体积收缩率先下降后上升;用不同偶联剂对填料进行表面处理后,复合材料的体积收缩率较未用偶联剂处理的复合材料低,且用偶联剂硬脂酸处理填料比用偶联剂KH-570更有利于复合材料体积...     

Correlation of side chain mobility with cholesterol retention by phospholipid vesicles

Multilamellar vesicles were prepared from choline phospholipids with various fatty acyl chains, singly and in mixtures, with and without cholesterol. Mobility of acyl side chains for each type of vesicle was measured by fluorescence polarization with diphenylhexatriene, and the amounts of cholesterol and phospholipid retained by them after extraction with a nonpolar solvent were determined. The data suggest that structures of acyl chains determine the extractability of cholesterol. Phosphatidylcholines with unsaturated or short saturated side chains above transition temperature retain less cholesterol upon extraction with petroleum ether than phosphatidylcholines with saturated side chains below transition temperature. Correlation of cholesterol retention with side chain mobility showed that cholesterol is more easily removed from vesicles with mobile acyl side chains than from vesicles with rigid side chains. The presence of cholesterol also alters extractability of phospholipids from vesicles and suggests that sterol affects the polarity rather than spacing of headgroups on vesicle surfaces.     

甲型肝炎病毒与水痘病毒感染2BS细胞的超微结构变化

目的观察甲型肝炎病毒(Hepatitis A virus,HAV)、水痘带状孢疹病毒(Varicella zoster virus,VZV)分别感染与共同感染二倍体细胞2BS株时细胞超微结构的变化。方法电镜观察HAV单独感染21、23、25 d,VZV单独感染1、3、5 d及HAV感染21 d后再以VZV感染1、3、5、7 d的2BS细胞的超微结构。结果与正常对照2BS细胞相比,单独感染HAV的2BS细胞超微结构无明显变化;单独感染VZV的2BS细胞的超微结构主要出现核膜破坏;HAV与VZV共同感染的2BS细胞核内出现VZV包涵体,核膜缺失,胞浆中可见HAV与VZV形态,且细胞粗面内质网和滑面内质网膨胀,内质网小池内有致密颗粒。结论HAV与VZV共同感染的2BS细胞的超微结构与两种病毒单独感染的细胞的超微结构存在不同的变化规律和形态特征,先感染HAV后感染VZV的2BS细胞比单独感染VZV的2BS细胞受到的破坏程度轻。     

环保型粘合剂XCB-2在全钢载重子午线轮胎胎体胶中的应用

研究环保型橡胶粘合剂XCB-2在全钢载重子午线轮胎胎体胶中的应用,并与间苯二酚和间苯二酚-甲醛树脂(以下简称间甲树脂)进行对比。结果表明:分别采用粘合剂XCB-2和间苯二酚-80等量替代间甲树脂,采用粘合剂XCB-2的胶料加工安全性最好,采用间甲树脂的胶料次之,采用间苯二酚-80的胶料最差;采用粘合剂XCB-2的胶料硫化速率与采用间甲树脂的胶料相当,均低于采用间苯二酚-80的胶料;采用粘合剂XCB-2的胶料物理性能和与钢丝帘线的粘合性能比采用间甲树脂的胶料略好;采用粘合剂XCB-2的胶料工艺性能良好,成本降低。     

不同排列结构的纤维层对捕集PM2.5性能影响的数值模拟

基于离散颗粒模型(Discrete Phase Model,DPM)研究了三种纤维排列结构捕集颗粒物规律.模拟了不同排列结构的纤维层在拦截和惯性碰撞两种捕集机制下捕集颗粒物的性能,考察了颗粒物粒径、入口风速和纤维层填充率对平行排列、单层垂直排列和双层垂直排列纤维层捕集颗粒物性能的影响.结果表明,当颗粒物粒径为0.5～2...     

A new route to functional polymers: Synthesis of functional polymer-supported esters from a weak acid ion exchange resin

Treatment of Amberlite IRC-50, a weak acid cation exchange resin containing methacrylic acid residues, with tetra-n-butylammonium hydroxide or benzyltrimethylammonium hydroxide gives the corresponding polymer-supported quaternary ammonium salts. These react smoothly, in nucleophilic substitution reactions, with a range of alkyl halides or sulfonates to give side chain esters with saturated hydrocarbon groups, with quaternary ammonium or sulfonate salt groups, with halide or alcohol groups at the terminus of spacer chains, with 1,2-diol groups, with acetylenic groups or with anthracene residues. These polymer-supported species have a variety of potential applications.     

白炭黑补强热塑性聚烯烃(POE)的性能研究

研究了不同品种和用量的白炭黑，偶联剂处理过的白炭黑以及白炭黑／炭黑并用补强POE的性能。结果表明，白炭黑对POE具有较好补强性能，不同牌号白炭黑的补强效果有一定的差异；用硅烷偶联剂VTPS处理的白炭黑补强POE的效果不明显；与同样粒径的炭黑相比，白炭黑补强POE的效果较好。     

起爆方式对线性聚能装药射流形成的影响

以工程中常用的柔性切割器为研究对象,在不考虑端部效应的前提下,对3种起爆方式下线性聚能装药射流的形成过程进行了理论分析和数值模拟。结果表明,不同起爆方式下射流头部速度以端部面起爆最大,线起爆次之,端部点起爆在端面附近处形成的最低,但在距端面一定距离处,射流头部速度又能增大到与端部面起爆的速度相近。在射流内部,端部面起爆形成的射流在内部各点处的速度都是3种起爆方式中最大的,而端部点起爆时,则是随着距起爆点距离的增加由处处小于线起爆的射流速度分布转变到与端部面起爆相同的射流速度分布。在此基础上进一步提出3种起爆方式下线性聚能装药切割目标的数值模拟方法。     

Poly(2,4-perfluoroalkylene-6-Perfluoroalkyltriazine)s,new high temperature elastomers

Poly(perfluoroalkyleneimidoylperfluoroalkylenoamidine)s have been prepared by the reaction of perfluoroalkane dinitriles with ammonia or with the diamidines of the dinitriles. The imidoylamidine polymers were treated with anhydrides to give poly(perfluoroalkyIenetriazine)s. Treatment of the imidoylamidine polymer with perfluoroglutaric anhydride or 4-cyanoperfluorobutyryl chloride gave pendant carboxyl or nitrile groups, respectively, on the triazine polymer which served as crosslinking sites. The formation of triazine crosslinks from the nitrile-pendant groups by trimerization with catalysts such as tetraphenyltin has given crosslinked polymers with tensile strengths of 1500 p.s.i., 70% elongation, and with thermal stability aproaching that of the original gum. The milling of catalysts and fillers with the polymer decreased the thermal stability in comparison with the original gum.     

Photoinitiated surface grafting of synthetic fibers,IV. Applications of textile dyes onto surface-photografted synthetic fibers

High-strength polyethylene (HSPE), polypropylene (PP), poly(ethylene terephthalate) (PET), and poly(vinyl alcohol) (PVA) textile yarns have been surface-photografted with various functional monomers, such as acrylic acid (AA), acrylamide (AM), glycidyl acrylate (GA) and 4-vinyl pyridine (VP), by means of the continuous presoaking process developed. The dyeing of these surface-modified yarns with various textile dyes has been investigated. In general, considerable improvements of dyeability have been observed. The dye adsorption of the surface-photografted fibers is influenced by many factors, such as type of fiber, amount and properties of the functional monomer grafted on the surface of the fibers, type of textile dye, etc. The fibers surface-grafted with a monomer containing basic groups, such as acrylamide and 4-vinyl pyridine, are efficiently dyed with an acid dye. Conversely, a fiber surface-grafted with acidic functional monomer is easily dyed to deep shades with basic dyes. The dye adsorption increases monotonically with increasing grafting measured in ESCA spectra as relative intensities of relevant lines. The ungrafted HSPE, PP and PET fibers can be dyed to some extent with certain dyes. In the present work, the dye adsorption increased by 3.4 times for HSPE fiber grafted with GA and dyed with the metal complex dye IO, by 7.9 times for PP fiber grafted with AA and dyed with the basic dye MB, by 6.1 times for PET with AM and with the direct dye SL, and by about 15.3 times for PVA with VP and with the acid dye TE.     

The Emerging Role of Venetoclax-Based Treatments in Acute Lymphoblastic Leukemia

Venetoclax, a B-cell lymphoma (BCL-2) inhibitor, in combination with hypomethylating agents has become the new standard of care in elderly and unfit patients with acute myeloid leukemia, with significantly improved overall survival and quality of life. Studies of venetoclax combined with high-dose chemotherapy are emerging with evidence of higher rates of molecular remission. Recently, a growing number of publications bring forth the use of venetoclax in patients with acute lymphoblastic leukemia (ALL). In the current review, we present the biological rationale of BCL-2 inhibition in ALL, how the interplay of BH3 proteins modulate the response and the current clinical experience with various combinations.