有机膨润土辛硫磷缓释剂的制备和释放研究

使用缓释剂是减少农药对环境污染的有效策略。为开发成本低廉且具有释放速度调节能力的农药缓释剂,以十六烷基三甲基氯化铵(HTMAC)为改性剂制备的有机膨润土作为辛硫磷的载体,制备辛硫磷缓释颗粒剂,分析在水中辛硫磷颗粒剂的释放行为。结果显示,HTMAC改性有机膨润土对辛硫磷具有良好的吸附性能,其吸附量最高可达0.966 g/g膨润土。有机膨润土极大延缓了辛硫磷的释放速率,控制季铵盐的用量可以在一定程度上调节辛硫磷的释放速率,50%辛硫磷活性成分从改性剂用量为50%、100%和150%可交换阳离子容量的有机膨润土颗粒剂的释放时间T50分别为普通颗粒剂的3.4倍、10.4倍和10.1倍。     

相对因子宽度与可S-因子分解矩阵

设S是实数集R的一个非空子集,如果存在S上的矩阵B,使得A=BBT,则称A是可S-因子分解的.对于一个实对称矩阵A,如果存在一个最小正整数k以及实矩阵(长方形)V,使得A=VVT,且V的每一列至多只有k个非零元素,则称A的因子宽度为k.利用可S-因子分解矩阵的S-秩以及因子宽度,引入相对因子宽度的定义,给出了一些可{0,1}-因子分解矩阵的相对因子宽度与因子分解之间的关系,最后利用S-秩和相对因子宽度,刻画了一类矩阵.     

关于鳞状因子循环矩阵的非奇异性

对于复数域上的n阶方阵4，如果满足AR＝RA，则称A为鳞状因子循环矩阵，其中R为基本鳞状因子循环矩阵。文中给出了仅用鳞状因子循环矩阵的第一行元素及对角阵D中的常数dl，d2，…，dn就可判断其非奇异性的3种简便方法。     

Bradykinin and nerve growth factor release the capsaicin receptor from PtdIns(4,5)P2-mediated inhibition.

Tissue injury generates endogenous factors that heighten our sense of pain by increasing the response of sensory nerve endings to noxious stimuli. Bradykinin and nerve growth factor (NGF) are two such pro-algesic agents that activate G-protein-coupled (BK2) and tyrosine kinase (TrkA) receptors, respectively, to stimulate phospholipase C (PLC) signalling pathways in primary afferent neurons. How these actions produce sensitization to physical or chemical stimuli has not been elucidated at the molecular level. Here, we show that bradykinin- or NGF-mediated potentiation of thermal sensitivity in vivo requires expression of VR1, a heat-activated ion channel on sensory neurons. Diminution of plasma membrane phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) levels through antibody sequestration or PLC-mediated hydrolysis mimics the potentiating effects of bradykinin or NGF at the cellular level. Moreover, recruitment of PLC-gamma to TrkA is essential for NGF-mediated potentiation of channel activity, and biochemical studies suggest that VR1 associates with this complex. These studies delineate a biochemical mechanism through which bradykinin and NGF produce hypersensitivity and might explain how the activation of PLC signalling systems regulates other members of the TRP channel family.     

载有溶菌酶微球的凝胶埋植剂的释药特性

为实现生物大分子药物的体内长期缓释,将药物制成乳酸/羟基乙酸共聚物(PLGA)的微球,再将微球分散于甲基纤维素反向温敏凝胶骨架中,制成微球-温敏凝胶复合埋植剂.通过体外释放实验,考察复合体系对模型药物溶菌酶的控释效果;通过凝胶色谱和扫描电镜,考察单独的微球以及在复合体系中的微球降解过程,分析凝胶介质对微球降解特性的影响;采用Peppas经验式来描述释放机制.结果表明: 在微球-凝胶复合体系中,溶菌酶可平稳释放30 d以上,无突释;药物释放是由载体溶蚀和药物扩散作用共同控制的.     

域Zp上的置换因子循环矩阵的逆阵

利用多项式的快速算法,给出了求域Zp上的置换因子循环矩阵的逆阵及Moore—Penrose逆的快速算法,最后给出的数值例子证明了该算法的有效性,该算法不需要预先知道置换因子循环矩阵的奇异性．     

Antisera to a synthetic peptide of the sis viral oncogene product recognize human platelet-derived growth factor

It has recently been reported that the sequences of the sis oncogene of simian sarcoma virus (SSV) and of human platelet-derived growth factor (PDGF) are very similar, establishing the most solid link yet between the mitogenic actions of growth factors and the transforming proteins of retroviruses. To investigate molecular mechanisms of transformation I have produced antisera against synthetic peptides corresponding to segments of the protein sequences predicted by the nucleotide sequences of viral oncogenes. Applying this approach to the case of sis and PDGF, I report here the results of probing outdated human platelets with an antiserum directed against a synthetic peptide representing residues 139-155 of the predicted sequence of the SSV transforming protein, p28sis (ref. 3). I detected peptides of apparent molecular weights (MWs) 30,000 to 31,000 (30-31K) and 16-18K, which correspond to the apparent molecular weights of nonreduced and reduced PDGF. In addition, a peptide of MW 21,000 was detected in platelets and a protein of MW 56,000 was detected in SSV-infected marmoset cells.     

由Hadamard矩阵构造的码

由Hadamard矩阵构造的码称为Hadamard码.文章根据Hadamard矩阵,用不同的方法构造出新的0,1矩阵,以此为生成矩阵生成了一类特殊的码;研究它的一些性质,证明了二元码C(2n-2, n-1)是自正交码的充分必要条件是n≡4(mod8),以及二元码C(2n-2, n-1)是自正交码的充分必要条件是二元码C(2n-2, n-1)是自对偶码.     

亲水/疏水半互穿网凝胶对牛血清白蛋白的控制释放

以牛血清白蛋白为对象,研究了亲水/疏水(QPVPD/PAAc)半互穿网凝胶对牛血清白蛋白的吸附与释放过程.在吸附过程中,当溶液pH值在牛血清白蛋白等电点(4.7)附近时,凝胶对蛋白质的吸附值最大;而在释放过程中,pH=7的释放率远大于其它pH值时的释放率.实验表明凝胶结构对蛋白质吸附与释放有较大影响.随着疏水成分的增加,凝胶对牛血清白蛋白的释放速率变缓.     

Specific anti-tumor effect induced by attenuated Salmonella typhimurium vaccine expressing extracellular region of vascular endothelial growth factor receptor 2

The purposes of this research were to study the stable expression of exogenous gene encoding therapeutic protein in attenuated Salmonella typhimurium, observe the metabolism of oral gene vaccine carried by attenuated Salmonella typhimurium in BALB/c mouse, and investigate the feasibility of prevention and treatment of tumors by the recombinant bacteria. Recombinant plasmid pcDNA3.1 VEGFR2(n1-7) was transformed into competent attenuated Salmonella typhimurium SL3261 to develop oral DNA vaccine SL3261-pcDNA3.1 VEGFR2(n1-7). To observe whether the exogenous gene can be expressed in the recombinant bacteria, PCR was performed to amplify the CMV promoter of the eukaryotic expression vector as the proof of stable expression of exogenous protein; transmission elec- tron microscopy (TEM) was applied to observe the morphology of the recombinant bacteria to confirm that the exogenous gene has no impact on the growth of the bacteria, and then BALB/c mice were immunized with the gene vaccine. After inoculation of the gene vaccine, the recombinant bacteria SL3261 could be detected in the tissues such as small intestine, colon, liver and spleen. And then, mice in each group were challenged with tumor cells. The results of animal experiment showed that tumor growth of the mice in experimental group was inhibited and survival time of immunized mice was prolonged compared with control groups. A higher lymphocyte infiltration in tumors from animals treated with DNA vaccine was observed. Immunohistochemical analysis of tumor samples revealed an en- hanced accumulation of CD8 cytotoxic T lymphocytes, as well as an increase in CD4 cells in the tumors of animals treated with the oral gene vaccine compared to tumors from control group mice. Ultrastructure of the tumor tissue showed that tumor cells in the samples of the immunized mice were well-differentiated. Our research confirmed that the exogenous gene can be stably expressed in the attenuated Salmonella typhimurium and has no impact on the growth of the recombinant bacteria; the exogenous gene can de delivered to the host by attenuated Salmonella typhimurium to produce anti-tumor effect with no obvious cytotoxity to the host. In this study, it is established that attenuated Salmonella typhimurium could be used as a vector for oral gene vaccine, and our study provided a theoretical basis for the body distribution and the metabolism of the recombinant bacteria. This strategy may provide a simple, safe and effective way for the prevention and treatment of tumors.     

神经生长因子

概述了神经生长因子的分子结构及作用机制，综述了神经生长因子的生理功能，神经生长因子不仅对神经细胞的存活，生长发育，分化，再生和功能维持起调控作用。同时也能诱导细胞凋亡。     

Vaccinia virus encodes a polypeptide homologous to epidermal growth factor and transforming growth factor

Epidermal growth factor (EGF) and transforming growth factor type I (TGF) are polypeptides of 53 and 50 amino acid residues, respectively. Both bind to EGF receptor, a 1,200-residue transmembranous glycoprotein, leading to phosphorylation of the receptor, enhancement of its tyrosine-specific kinase activity and ultimately to stimulation of cell growth. We report here that a 140-residue polypeptide encoded by one of the early genes of vaccinia virus (VV) is related closely to EGF and TGF. The presence of putative signal and transmembranous sequences further suggests that the viral protein might be an integral membrane protein, but that, as in the case of EGF itself, the membrane-associated form may be the precursor of a soluble growth factor. Production of EGF-like growth factors by virally infected cells could account for the proliferative diseases associated with members of the poxvirus family such as Shope fibroma virus, Yaba tumour virus, and molluscum contagiosum virus (MCV).     

晶种辅助法控制合成CdS纳米棒

本论文以CS2为硫源．首先在十六烷基三甲基溴化铵(CTAB)胶束中制备CdS纳米棒品种．然后利用晶种辅助法实现了不同长径比的CdS纳米棒制备。实验结果表明晶种辅助生长法能否成叻与晶种在反应体系中溶解特性有很大关系。     

Effects of extracellular calmodulin on pollen germination and tube growth

The effects of calmoddin (CaM) antagonist W7-agarose, anti-CaM serum and exogenous purified CaM on pollen germination and tube growth ofForsythia suspensu were studied. The pollen germination and tube growth were inhibited or completely stopped by CaM antagonist W7-agarose. The addition of exogenous purified CaM stimulated pollen germination and tube growth, whereas the same amount of bovine serum albumin (BSA) had no effect. The inhibitory effects caused by W7-agarose and anti-CaM serum could be reversed completely by the addition of exogenous purified CaM. The tube growth of germinated pollen was also inhibited or completely stopped by W7-agarose. The results suggest that endogenous extracellular CaM initiates pollen germination and tube growth, whereas exogenous CaM enhances the above processes.