不同粒径聚苯乙烯微球的制备及其胶体晶体的组装

通过控制聚合反应时间、体系离子强度、离子共聚体(苯乙烯磺酸钠)浓度等因素,采用无皂乳液聚合方法,成功制备了单分散性聚苯乙烯(PS)胶体微球,并使之形成面心立方(fcc)密堆积为主的胶体晶体.利用FDTD方法计算了胶体晶体表面的显色特性,和实验结果相符.     

韩国开发出大量生产纳米粒子的新技术

韩国科学家最近开发出一种生产铁、锰等金属纳米粒子的新技术,与传统方法相比,新技术能使金属纳米粒子的生产成本更低,产量更高。     

银氨溶液浸润的二氧化硅微球表面的银镜反应

采用银镜反应的方法,实现了在二氧化硅微球表面纳米银粒子的制备.通过改变反应温度、银氨溶液的浓度、还原剂的种类以及离心洗涤的次数,可以时纳米银粒子的粒径、包覆程度和反应速度进行调节.纳米银粒子包覆的二氧化硅胶体微球的微观结构可利用透射电子显微镜(TEM)进行表征.     

试验验证纳米金粒子的神奇特性

据physorg网站日前报道，作为生物分子，金的纳米粒子具有灵敏的“可操作性”，能够在介质激光的作用下进行高效的操作及跟踪，但它们的升温速度也非常快——十亿分之几秒内就可以升温几十度。根据来自玻尔得美国科罗拉多州大学与美国全国技术标准协会（NIST）联合会（JILA）科学家的研究显示，这个特性即能够破坏金的分子结构，同时也有助于人类的研究。     

基于纳米粒子的超声速流动成像

由于超声速流动受到可压缩性、激波、不稳定性以及湍流等因素的影响, 现有流动显示与成像技术在流场结构的高时空分辨率和高信噪比测量中存在一定的问题. 为此, 本文提出了基于纳米粒子的平面激光散射技术（NPLS）, 该技术以纳米粒子作为示踪粒子, 以脉冲平面激光作为光源, 通过CCD记录流场中的粒子图像实现超声速流动的高分辨率成像. 根据多相流体动力学理论和斜激波校准实验研究了纳米粒子在超声速流动中的跟随性问题. 根据光散射理论深入分析了影响纳米粒子散射光强的各种因素. 理论和实验研究结果表明, 纳米粒子的动力学行为和光散射特性大大提高了NPLS技术的时空分辨率和信噪比, 能够再现激波、膨胀波、马赫盘、边界层、滑移线和混合层共存的精细流场结构.     

钴及其化合物一维纳米材料的制备研究进展

本文介绍了钴及其化合物一维纳米材料,如纳米线、纳米棒和纳米管的制备方法及其最新研究进展,包括热分解法、模板法、分子自组装、固相合成法和化学溶液法等。并预测了未来的可能的发展方向。     

壳聚糖磁性光敏剂血卟啉衍生物微球的制备及其体外表征研究

目的制备壳聚糖包覆的磁性光敏剂血卟啉衍生物微球并考察其体外表征。方法以五羰基铁为原料制备羰基铁粉纳米颗粒,非溶剂法将羰基铁粉纳米颗粒与光敏剂血卟啉衍生物HPD复合,并用壳聚糖包覆制备成壳聚糖包覆磁性血卟啉衍生物微球(CS-M-HPD)。使用电子显微镜、激光粒度仪、X-射线衍射仪和磁力测定仪考察微球的表征。结果检测结果表明该微球为球形,分散性良好,粒径大多集中在290～300 nm。微球羰基铁粉纯度高,呈现优良磁性。结论本研究实现了壳聚糖对磁性HPD的包覆,得到了单分散性磁性HPD微球,为进一步研究该微球靶向光动力治疗肿瘤的生物活性奠定了实验基础。     

油酸功能化金属有机框架纳米片的摩擦学性能研究

利用对苯二甲酸与乙酸铜为原料,采用超声辅助自组装合成了铜基金属有机框架(Cu-MOF)纳米片,之后通过超声处理将油酸分子修饰于Cu-MOF表面,得到Cu-MOF@OA纳米片.相比于Cu-MOF纳米片, Cu-MOF@OA纳米片在保持片状结构的同时,其尺寸进一步减小,同时也使团聚问题得到了极大改善,在基础油500 N中表现出良好的分散稳定性.摩擦学试验表明,在1.0 wt.%的添加浓度下, Cu-MOF@OA展现出最佳的摩擦学性能,其摩擦系数降低至基础油的3/5,磨损体积降低至基础油的1/6.最后,利用扫描电子显微镜(SEM)与X射线光电子能谱(XPS)对Cu-MOF@OA纳米片润滑后的磨痕进行形貌和特征元素的表征,探究其润滑机制.结果表明,摩擦过程中在负载和剪切应力的共同作用下, Cu-MOF@OA纳米片、基础油以及铁基底三者之间发生了复杂的摩擦化学反应,形成了由含氮物质、含碳物质与铁氧化物组成的摩擦膜,降低了摩擦磨损.     

相转移法制备γ’-Fe_4N纳米粒子的合成过程及生长机制

采用化学气相法合成了Fe/N多相纳米粒子,揭示了合成参数对产物性质的影响,确定了最佳的合成工艺路线.对生成的粒子进行第2次氮化,实现了纳米粒子的相转移,获得了均匀单相的γ-Fe4N纳米粒子.分析了粒子的成核与生长机制,对相转移过程给出了合理解释.此外,初步表征了相转变前后纳米粒子的形貌、粒径、物相、成分及磁学特性.     

相转移法制备γ'-Fe4N纳米粒子的合成过程及生长机制

采用化学气相法合成了Fe/N多相纳米粒子, 揭示了合成参数对产物性质的影响，确定了最佳的合成工艺路线. 对生成的粒子进行第2次氮化，实现了纳米粒子的相转移，获得了均匀单相的γ'-Fe₄N纳米粒子. 分析了粒子的成核与生长机制，对相转移过程给出了合理解释. 此外，初步表征了相转变前后纳米粒子的形貌、粒径、物相、成分及磁学特性.     

Functional reinnervation of cat sympathetic ganglia with splenic nerve homografts

Zusammenfassung Sympathische Ganglien, wenn mit Fasern desN. splenicus reinnerviert, bilden 2 pharmakologisch differente Synapsengruppen: normale, vom cholinergischen Typ und ca. 20% exitatorische vom «monoaminergischen» Typ, wenn sie von adrenergen Fasern reinnerviert wurden.     

Functional diversity and pharmacological profiles of the FKBPs and their complexes with small natural ligands

From 5 to 12 FK506-binding proteins (FKBPs) are encoded in the genomes of disparate marine organisms, which appeared at the dawn of evolutionary events giving rise to primordial multicellular organisms with elaborated internal body plan. Fifteen FKBPs, several FKBP-like proteins and some splicing variants of them are expressed in humans. Human FKBP12 and some of its paralogues bind to different macrocyclic antibiotics such as FK506 or rapamycin and their derivatives. FKBP12/(macrocyclic antibiotic) complexes induce diverse pharmacological activities such as immunosuppression in humans, anticancerous actions and as sustainers of quiescence in certain organisms. Since the FKBPs bind to various assemblies of proteins and other intracellular components, their complexes with the immunosuppressive drugs may differentially perturb miscellaneous cellular functions. Sequence–structure relationships and pharmacological profiles of diverse FKBPs and their involvement in crucial intracellular signalization pathways and modulation of cryptic intercellular communication networks were discussed.     

Functional consequences of treating turkey liver fructose-1,6-bisphosphatase with penicillin G

Summary Treatment of turkey liver fructose-1,6-bisphosphatase with penicillin G progressively inactivated the enzyme and desensitized the enzyme toward high substrate inhibition. The treatment also led to reduced sensitivity to AMP inhibition and the loss of cooperative interaction among AMP-binding sites. These altered properties were not reversed by dialysis, but were prevented when treatment with penicillin G was performed in the presence of substrate.This work was in part supported by grant RR-8006 from the General Research Branch, Division of Research Resources, NIH (USA) and in part by Faculty Research Grant from Southern School of Pharmacy, Mercer University, Atlanta (Georgia, USA).     

土壤重金属污染及防治措施

本文主要简述了土壤中重金属污染的来源、重金属存在的不同形态及在土壤-生物系统中重金属的生态效应。根据重金属污染特点，分析了目前土壤重金属污染防治措施中的优缺点。     

Functional and physical communication between oncoproteins and tumor suppressors

The discovery of oncogenes (c-onc’s) and tumor suppressors (TS’s) has led to the concept that cancer arises from defects in each of these classes of genes or their products. More recently, it has been appreciated that c-onc and TS proteins often affect one another’s functions. Within this context, I review the two classical TS’s, p53 and the retinoblastoma protein, and the consequences of their inactivation. The various forms of genomic instability (GI) that underly the high mutation rates of transformed cells are then discussed. Particular emphasis is placed upon the concept that GI is not only an integral part of the transformed state but is a prerequisite. Increased oxidative DNA damage, and/or an inabiliy to repair it, can lead to GI. The review then discusses recent observations showing that loss of the TS protein peroxiredoxin 1 (prdx1) and increased expression of the c-onc protein c-Myc, each leads to increased oxidative DNA damage. The critical nature of the c-onc-TS interaction is underscored by that occurring between prdx1 and c-Myc, with the former protein regulating the production of DNA-damaging reactive oxygen species by the latter. The intimate association between these proteins and others serves as a paradigm for the exquisite balancing act that c-onc’s and TS’s must maintain in order to properly control normal DNA replication and cellular proliferation while simultaneously minimizing the acquisition of potentially neoplastic mutations. Received 10 May 2005; received after revision 3 July 2005; accepted 19 July 2005     

Functional consequences of treating turkey liver fructose-1,6-bisphosphatase with penicillin G.

Treatment of turkey liver fructose-1,6--bisphosphatase with penicillin G progressively inactivated the enzyme and desensitized the enzyme toward high substrate inhibition. The treatment also led to reduced sensitivity to AMP inhibition and the loss of cooperative interaction among AMP-binding sites. These altered properties were not reversed by dialysis, but were prevented when treatment with penicillin G was perfomed in the presence of substrate.     

融合块结构的等周算法及其在CT图像分割中的应用

等周分割是一种基于图谱理论的分割算法,能有效提高图像分割质量且有较高的效率及稳定性.本文提出了一种融合块结构的等周分割算法.该算法采用块结构来减少图中节点数.并根据CT图像特征,将该算法应用到CT图像分割中.实验结果表明,融合块结构的等周分割算法在CT图像分割中取得较好的分割效果,并大大提高了分割效率.