杜仲橡胶硫化胶交联密度与结晶性能关系研究

采用差示扫描量热(DSC)法分析杜仲橡胶硫化胶交联密度对其物理性能和结晶性能的影响。结果表明:随着硫黄用量的增大,杜仲橡胶硫化胶的交联密度增大,邵尔A型硬度减小,100%定伸应力、拉伸强度和拉断伸长率先增大后减小;消除热历史后杜仲橡胶生胶的结晶特征减弱;随着交联密度的增大,硫化胶的DSC特征熔融峰减弱直至消失,结晶峰钝化,峰面积减小。     

硫黄对杜仲橡胶形状记忆材料性能的影响

研究硫黄用量对杜仲橡胶形状记忆材料性能的影响。结果表明：随着硫黄用量的增大,胶料的ML变化不大,MH增大,t⁹⁰先缩短后延长;硫化胶的交联密度总体呈增大趋势,定伸应力和拉伸强度先减小后增大,热刺激响应回复温度呈减小趋势,最终形变回复率先增大后减小;动态力学性能测试发现,存在多相转变峰;当硫黄用量为1份时,硫化胶的物理性能和热致形状记忆性能最佳。     

核磁共振法表征硫黄用量对天然橡胶交联密度及结构的影响

用核磁共振(NMR)法测定了硫黄用量及硫化温度对天然橡胶(NR)硫化胶交联结构的影响,并与传统的平衡溶胀法进行了对比.结果表明,用NMR法可以测定硫化胶的总交联密度、未硫化胶的物理交联密度和由于交联反应产生的化学交联密度;NR硫化胶的总交联密度和化学交联密度随硫黄用量的增加而呈线性增加;随着硫黄用量的增加.交联密度增加,NR硫化胶的纵向弛豫时间和横向弛豫时间下降;NR硫化胶的交联密度越大,弛豫时间对温度的依赖性越小;NMR法可以清晰展示NR/硫黄/促进剂NS硫化体系的硫化过程中橡胶交联点间的相对分子质量、化学交联密度及橡胶大分子连到橡胶交联网络上的演变过程.     

天然橡胶/杜仲胶并用胶的交联密度与结晶度的关系及其对性能的影响

通过调整硫黄用量,研究天然橡胶(NR)/杜仲胶(EUG)并用胶的交联密度与结晶度的关系及其对并用胶性能的影响。结果表明：NR/EUG并用胶的交联密度与结晶度呈负相关;随着硫黄用量的增大,NR/EUG并用胶的交联密度增大,t₁₀略有缩短,t₉₀变化不大,硬度、耐屈挠性能和抗湿滑性能先提高后降低,滚动阻力和生热下降,储能模量波动减小;当硫黄用量为2～2.5份时,NR/EUG并用胶的交联密度和结晶度较大,物理性能、耐磨性能和抗湿滑性能较好。     

填充油用量对硫黄硫化EPDM的影响

采用橡胶加工分析仪,研究了填充油用量对硫黄硫化EPDM硫化特性和硫化胶交联网络结构的影响。结果表明,当填充油用量一定时,EPDM硫化胶的总交联密度与硫黄用量呈线性关系;当硫黄用量一定时,随着填充油用量的增加,EPDM混炼胶的最低扭矩和硫化程度不断降低,硫化速率减慢;EPDM硫化胶的物理缠结密度随填充油用量的增加而线性下降,填充油用量较大时,填充油对胶料的稀释作用在硫黄硫化EPDM总交联密度的降低中占主导地位。     

TPI形状记忆性能研究

研究硫黄用量对反式1,4-聚异戊二烯(TPI)硫化胶物理性能和热致形状记忆性能的影响以及TPI硫化胶的电致形状记忆性能。结果表明,随着硫黄用量的增大,TPI硫化胶化学交联密度和总交联密度增大,定伸应力和拉伸强度减小,拉断伸长率增大,热刺激响应回复温度降低,最终形变回复率增大,形变回复速率先增大后减小;TPI硫化胶具有良好的电致形状记忆性能,随着施加电压的增大,TPI硫化胶最终形变回复率增大,形变回复时间缩短。     

RPA分析硫黄用量对天然橡胶动态性能的影响

用橡胶加工分析仪(RPA)分析硫黄用量对NR动态性能的影响。结果表明:不同硫黄用量的混炼胶的动态模量随频率的升高和温度的降低而增加,损耗因子降低;应变超过28%,混炼胶的储能模量下降。不同硫黄用量的硫化胶随交联密度的提高,动态性能对频率的依赖性变小,对应变的依赖性变强;而温度越高,硫化胶的"橡胶弹性"越明显。     

硫化剂DTDM对EPDM硫化胶性能的影响

研究了在S＝－份、S＝0.5份情况下硫化剂DTDM对EPDM硫化胶性能的影响。结果表明：单独使用DTDM作硫化剂时,胶料的硫化速度慢、焦烧时间长、力学性能尚好;当少量硫黄与DTDM并用时,胶料的硫化速度加快、焦烧时间缩短,但对力学性能有所损害;当S＝0份、DTDM用量为4份和S＝0.5份、DTDM用量为3份时,EPDM硫化胶的交联密度都趋于一平衡值;无论是在S＝0份还是S＝0.5份的硫化体系中,硫化剂DTDM用量为3－3.5份时,EPDM有效 料的耐热老化性能都比较好。     

用过氧化物/硫黄体系硫化NBR/ZDMA复合材料的研究

研究硫化剂DCP和硫黄用量对NBR／甲基丙烯酸锌(ZDMA)复合材料硫化特性、物理性能及交联密度的影响。结果表明，在硫化剂DCP硫化的NBR／ZDMA复合材料中加入少量硫黄，能提高复合材料的综合物理性能；硫化剂DCP用量为1．5份、硫黄用量为0．6份时，复合材料的综合物理性能最佳，表观交联密度较小，玻璃化温度较低。     

采用回归法分析硫黄／DTDM并用此对硫化胶性能的影响

采用回归法分析了硫黄／ＤＴＤＭ并用比对硫化胶性能的影响,结果表明,合理的硫黄／ＤＴＤＭ并用比能赋予硫化胶较好的物理性能和抗热老化及抗疲劳性能。根据分析可以看出,硫化胶的定伸应力和交联密度与ＤＴＤＭ用量呈直线递增关系,拉伸强度和撕裂强度随ＤＴＤＭ用量的增大有一峰值出现;采用促进ＮＳ,而且当硫黄／ＤＴＤＭ并用比为０．６／２．４时,硫化胶综合性能最好。     

Synergistic Interactions of Cannabidiol with Chemotherapeutic Drugs in MCF7 Cells: Mode of Interaction and Proteomics Analysis of Mechanisms

Cannabidiol (CBD), a nonpsychoactive phytocannabinoid, has recently emerged as a potential cytotoxic agent in addition to its ameliorative activity in chemotherapy-associated side effects. In this work, the potential interactions of CBD with docetaxel (DOC), doxorubicin (DOX), paclitaxel (PTX), vinorelbine (VIN), and 7-ethyl-10-hydroxycamptothecin (SN−38) were explored in MCF7 breast adenocarcinoma cells using different synergy quantification models. The apoptotic profiles of MCF7 cells after the treatments were assessed via flow cytometry. The molecular mechanisms of CBD and the most promising combinations were investigated via label-free quantification proteomics. A strong synergy was observed across all synergy models at different molar ratios of CBD in combination with SN−38 and VIN. Intriguingly, synergy was observed for CBD with all chemotherapeutic drugs at a molar ratio of 636:1 in almost all synergy models. However, discording synergy trends warranted the validation of the selected combinations against different models. Enhanced apoptosis was observed for all synergistic CBD combinations compared to monotherapies or negative controls. A shotgun proteomics study highlighted 121 dysregulated proteins in CBD-treated MCF7 cells compared to the negative controls. We reported the inhibition of topoisomerase II β and α, cullin 1, V-type proton ATPase, and CDK-6 in CBD-treated MCF7 cells for the first time as additional cytotoxic mechanisms of CBD, alongside sabotaged energy production and reduced mitochondrial translation. We observed 91 significantly dysregulated proteins in MCF7 cells treated with the synergistic combination of CBD with SN−38 (CSN−38), compared to the monotherapies. Regulation of telomerase, cell cycle, topoisomerase I, EGFR1, protein metabolism, TP53 regulation of DNA repair, death receptor signalling, and RHO GTPase signalling pathways contributed to the proteome-wide synergistic molecular mechanisms of CSN−38. In conclusion, we identified significant synergistic interactions between CBD and the five important chemotherapeutic drugs and the key molecular pathways of CBD and its synergistic combination with SN−38 in MCF7 cells. Further in vivo and clinical studies are warranted to evaluate the implementation of CBD-based synergistic adjuvant therapies for breast cancer.     

关于科研开发效率的思考

作者从认识论和方法论的角度出发，对提高科研开发效率提出如下看法：１．当代的经济竞争，实质是科技产业化能力的竞争。２．研究开发应是从投入到产出的完整系统。３．产业部门的研究开发要面向市场。４．只有充分利用专利保护，才能在国际竞争中赢得主动。５．要保持竞争优势，须把信息工作提到新水平。     

Interphases in the Adhesive Bonding of Fluoropolymers

Strong and durable adhesive bonds may be made between polytetrafluoroethylene (PTFE) and either cyanoacrylate (CA) or epoxy adhesives, if the PTFE surface is modified by the use of a “primer” such as triphenylphosphine (TPP) or diaminodiphenylmethane (DDM). The primer mixes with the PTFE surface, and the modified surface is then capable of forming an interphase, tens to hundreds of nanometers thick, where interpenetration of the adhesive and adherend occurs. Using CA adhesives, PTFE/CA/PTFE block compression shear bond strength (ASTM D4501-85) of over 10 MPa can be achieved, with failure occurring cohesively. Initial work with epoxy adhesives indicates that the use of DDM primer gives adhesive bonds comparable in strength with those produced by modification of the fluoropolymer surface by sodium naphthalenide.     

玉米肽-麦芽糊精糖基化产物与α-生育酚共组装纳米粒子的制备及其性质

通过美拉德反应制备玉米肽-麦芽糊精糖基化产物,再通过反溶剂法制备糖基化产物与α-生育酚共组装纳米粒子,系统地研究了制备参数对于复合粒子的影响。结果表明,糖基化产物浓度、玉米肽与α-生育酚质量比、pH对于复合粒子的粒度与ζ电位有重要的影响。采用动态光散射、ζ电位观察发现,通过调节制备参数,荷载α-生育酚的玉米肽-麦芽糊精糖基化产物可以形成平均粒度为80～100 nm的纳米粒子,其表面电荷分布在-23～-32 mV之间。与玉米肽、玉米肽/麦芽糊精混合物相比,玉米肽-麦芽糊精糖基化产物对于α-生育酚具有更高的荷载效率以及更好的pH稳定性。     

Participation of Amyloid and Tau Protein in Post-Ischemic Neurodegeneration of the Hippocampus of a Nature Identical to Alzheimer’s Disease

Recent evidence suggests that amyloid and tau protein are of vital importance in post-ischemic death of CA1 pyramidal neurons of the hippocampus. In this review, we summarize protein alterations associated with Alzheimer’s disease and their gene expression (amyloid protein precursor and tau protein) after cerebral ischemia, as well as their roles in post-ischemic hippocampus neurodegeneration. In recent years, multiple studies aimed to elucidate the post-ischemic processes in the development of hippocampus neurodegeneration. Their findings have revealed the dysregulation of genes for amyloid protein precursor, β-secretase, presenilin 1 and 2, tau protein, autophagy, mitophagy, and apoptosis identical in nature to Alzheimer’s disease. Herein, we present the latest data showing that amyloid and tau protein associated with Alzheimer’s disease and their genes play a key role in post-ischemic neurodegeneration of the hippocampus with subsequent development of dementia. Therefore, understanding the underlying process for the development of post-ischemic CA1 area neurodegeneration in the hippocampus in conjunction with Alzheimer’s disease-related proteins and genes will provide the most important therapeutic development goals to date.     

表面张力对自由落体液滴形变的影响

液滴运动过程中的形状变化对液滴的蒸发、燃烧等过程有重要影响,表面张力是影响其形状变化的因素之一。为研究表面张力对液滴形变的影响规律,采用低浓度的表面活性剂(十二烷基苯磺酸钠SDBS)配制表面张力为30~72mN·m^-1的水溶液。利用不同外径的针管得到3~5mm粒径的液滴。高速摄像机(PhantomV211,1000pps,800×600pixel)对这些液滴在自由落体过程中的形变规律进行了可视化实验研究,得到了关于Eötvös数(Eo)的半经验关系式。实验结果表明,液滴在自由落体过程中会形成周期性振动形变,振动周期和振幅随表面张力增大而减小。进一步研究发现,初始时液滴形成并断裂所引起的瞬态冲量使液滴内部动量传递进而表现出周期性振动形变。     

小胶质细胞对阿尔兹海默病发生发展的影响作用

阿尔兹海默病(老年性痴呆,AD)是由β淀粉样蛋白(Aβ)和微管相关蛋白(Tau)聚集形成的具有毒性作用的寡聚物而引起的老年人主要以记忆力下降和脑部形成老年斑、神经纤维缠绕为特征的神经退行性疾病. 小胶质细胞作为中枢神经系统中的固有免疫细胞,是脑内免疫监视的关键成分,发挥内源性免疫防御作用. 正常生理状态的小胶质细胞能有效吞噬和清除毒性Aβ寡聚体,阻止AD发生. 在AD病理过程中,过度激活的小胶质细胞通过补体依赖途径过度吞噬突触,导致突触丧失,同时大量释放炎症因子,促进Tau相关病理变化,对神经元造成直接损伤,导致认知功能下降. 由此可见,小胶质细胞在AD发生发展过程中起着双刃剑的作用,探明小胶质细胞的极化状态及其在AD疾病机理中的作用将为攻克AD的药物研发提供突破性思路.     

Gender-Dependent Deregulation of Linear and Circular RNA Variants of HOMER1 in the Entorhinal Cortex of Alzheimer’s Disease

The HOMER1 gene is involved in synaptic plasticity, learning and memory. Recent studies show that circular RNA derived from HOMER1 (circHOMER1) expression is altered in some Alzheimer’s disease (AD) brain regions. In addition, HOMER1 messenger (mRNA) levels have been associated with β-Amyloid (Aβ) deposits in brain cortical regions. Our aim was to measure the expression levels of HOMER1 circRNAs and their linear forms in the human AD entorhinal cortex. First, we showed downregulation of HOMER1B/C and HOMER1A mRNA and hsa_circ_0006916 and hsa_circ_0073127 levels in AD female cases compared to controls by RT-qPCR. A positive correlation was observed between HOMER1B/C, HOMER1A mRNA, and hsa_circ_0073128 with HOMER1B/C protein only in females. Global average area of Aβ deposits in entorhinal cortex samples was negatively correlated with HOMER1B/C, HOMER1A mRNA, and hsa_circ_0073127 in both genders. Furthermore, no differences in DNA methylation were found in two regions of HOMER1 promoter between AD cases and controls. To sum up, we demonstrate that linear and circular RNA variants of HOMER1 are downregulated in the entorhinal cortex of female patients with AD. These results add to the notion that HOMER1 and its circular forms could be playing a female-specific role in the pathogenesis of AD.     

辉光放电电解降解水体中阳离子桃红FG的机理

用辉光放电电解（GDE）技术对模拟染料废水阳离子桃红FG的降解过程进行了研究。通过发射光谱法测定了GDE产生的活性粒子,用紫外光谱和总有机碳（TOC）分析仪研究了不同放电时间下的脱色率和去除率,用电导率仪和酸度计测定了降解过程中溶液的电导率和pH的变化,同时用离子色谱对降解中间产物进行了分析。结合各种分析结果,探讨了GDE降解阳离子桃红FG的机理。结果表明,在最佳电压600 V时,溶液中产生HO·、O·、H·等高活性粒子;放电120 min时,200 ml 20 mg/L阳离子桃红FG的脱色率和TOC去除率分别可达99.0%和72.6%;降解液pH先减小后增大,电导率存在先增大后减小的趋势;离子色谱测试表明,降解过程中产生多种有机小分子酸。羟基自由基（HO·）对阳离子桃红FG的降解起关键作用,GDE降解阳离子桃红FG的机理为：HO·作用下助色基团键断裂,产生酚类等中间产物,然后继续被降解为醌和小分子有机酸,最终矿化为Cl^-、NO₃^-、CO₂和H₂O。