pH值敏感水凝胶的合成及药物缓释性能研究

聚乙二醇(PEG)与丙烯酰氯反应合成聚乙二醇双丙烯酸酯(PEGDA)，然后以PEGDA、N—乙烯基—2—此咯烷酮(NVP)及丙烯酸为主要原料，N，N^ —亚甲基双丙烯酰胺(BIS)为交联剂，偶氮二异丁腈(AIBN)为引发剂，采用自由基聚合法合成了对pH值变化敏感的N—乙烯基—2—吡咯烷酮—丙烯酸—聚乙二醇双丙烯酸酯交联共聚物(po1y[NVP-AA-PEGDA])水凝胶．利用该共聚物为载体对抗癌药5—氟脲密啶(5—FU)进行包埋，并在SIF及SGF缓冲溶液中于37℃进行体外释药研究．结果表明，在pH值较小的缓释介质中药物释放曲线较平缓，释药周期较长，同时最终的平衡释药百分数也较小；随着样品中PEGDA量的减少，释药曲线趋于平缓，释药周期变长，最终的平衡释药百分数成小．     

三元能量对黑暗链霉菌高产菌株的筛选研究

介绍了１５０株三元能量处理妥布拉霉素（ＴＯＢ）正突变株的筛选研究，通过初筛获得２５株ＴＢＯ突变株，从中分离出１５株高产菌，进一步复筛双从中挑选出５株产量更高的产高菌株。通过最佳培养基配方的发酵试验，确定联抗性能最佳的菌株为ＱＢ－１３０－Ｓ１。实验表明：三元能量用于ＴＯＢ菌诱变，不仅提高了产抗水平，而且菌株生长时间缩短，经４次传代，高产菌株的遗传性能稳定。     

Properties of High Strength Steel Fiber Reinforced Concrete under Compression

ＰｒｏｐｅｒｔｉｅｓｏｆＨｉｇｈＳｔｒｅｎｇｔｈＳｔｅｅｌＦｉｂｅｒＲｅｉｎｆｏｒｃｅｄＣｏｎｃｒｅｔｅｕｎｄｅｒＣｏｍｐｒｅｓｓｉｏｎＱｉａｎＣｈｕｎｘｉａｎｇ（钱春香）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅ...     

氧化淀粉控释材料的研究

本文探索研究了氧化淀粉替代海藻酸钠的可能性,系统考察了制备条件对氧化淀粉性能的影响,包括反应温度、pH值、淀粉乳浓度、氧化剂用量等因素及其各种条件下的羧基含量。实验表明,随着pH值的降低,淀粉乳浓度的增加,氧化剂用量的增加,羧基含量有所增加。温度影响反应速度,温度对羧基含量影响不显著,考察了自制备氧化淀粉的成膜可行性。     

关于加快发展专业学位研究生教育的思考

加快发展,已成为近期专业学位研究生教育的政策基调。从发展动因、发展模式和发展趋势来看,专业学位研究生教育的加快发展具有补偿性发展、多元化发展和示范性发展的特征。     

学术期刊不应收取论文“加急费”

针对一些期刊收取论文"加急费"的现象,指出其可能带来的一些弊端,同时提出了防范对策。     

教育功能释放的三重境界

论述了教育的功能,认为本体功能是培养人,教育的其他功能都只是其派生功能。依据教育的主体——人的“存在状态”,将教育功能的释放分成生存境界、生活境界和生命境界。分析了在对人的培养和对社会发展两方面分别体现为个体谋生功能、“成事”功能;个体乐生功能、“成人”功能;个体享用功能、“成己”功能。这三层境界是相互交织、相互转化的螺旋上升过程;是追求教育功能从有用到有意义,从有限到无限的过程。     

Gene expression and apoptosis response in hepatocellular carcinoma cells induced by biocompatible polymer/magnetic nanoparticles containing 5-fluorouracil

BackgroundSuper-paramagnetic iron oxide nanoparticles (SPION) contain a chemotherapeutic drug and are regarded as a promising technique for improving targeted delivery into cancer cells.ResultsIn this study, the fabrication of 5-fluorouracil (5-FU) was investigated with loaded Dextran (DEX-SPION) using the co-precipitation technique and conjugated by folate (FA). These nanoparticles (NPs) were employed as carriers and anticancer compounds against liver cancer cells in vitro. Structural, magnetic, morphological characterization, size, and drug loading activities of the obtained FA-DEX-5-FU-SPION NPs were checked using FTIR, VSM, FESEM, TEM, DLS, and zeta potential techniques. The cellular toxicity effect of FA-DEX-5-FU-SPION NPs was evaluated using the MTT test on liver cancer (SNU-423) and healthy cells (LO2). Furthermore, the apoptosis measurement and the expression levels of NF-1, Her-2/neu, c-Raf-1, and Wnt-1 genes were evaluated post-treatment using flow cytometry and RT-PCR, respectively. The obtained NPs were spherical with a suitable dispersity without noticeable aggregation. The size of the NPs, polydispersity, and zeta were 74 ± 13 nm, 0.080 and −45 mV, respectively. The results of the encapsulation efficiency of the nano-compound showed highly colloidal stability and proper drug maintenance. The results indicated that FA-DEX-5-FU-SPION demonstrated a sustained release profile of 5-FU in both phosphate and citrate buffer solutions separately, with higher cytotoxicity against SNU-423 cells than against other cells types. These findings suggest that FA-DEX-SPION NPs exert synergistic effects for targeting intracellular delivery of 5-FU, apoptosis induction, and gene expression stimulation.ConclusionsThe findings proved that FA-DEX-5-FU-SPION presented remarkable antitumor properties; no adverse subsequences were revealed against normal cells.How to cite: Mahdia SA, Kadhimb AA, Albukhaty S, et al. Gene expression and apoptosis response in hepatocellular carcinoma cells induced by biocompatible polymer/magnetic nanoparticles containing 5-fluorouracil. Electron J Biotechnol 2021;52. https://doi.org/10.1016/j.ejbt.2021.04.001     

论歌唱演员的紧张心理与调控

紧张心理对声乐表演产生了严重的影响,它直接影响表演的效果,文章从心理学和音乐实践的关系中,对紧张心理的成因及表现、矫正与克服几方面进行了探讨。     

掷标枪最后用力左侧支撑的作用

从生物力学角度对掷标枪左侧支撑动作进行了全面分析 ,论证了左侧支撑是掷标枪技术中的重要技术环节。