Über die Chemie des Enniatins

Summary Judging by the physical and chemical properties and bacterial spectra, the antibiotic substance, Enniatin, previously isolated from a strain ofFusarium by the authors, appears to be identical with that which was recently reported byCook et al. derived from another strain and designated by them as Lateritiin-I, although the reported empirical formulæ differ. Numerous physical and chemical characteristics of Enniatin and its degradation products are given, and, further, two relatedFusarium antibiotics, here designated as Enniatin B and C, are briefly described.

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Ausgeführt mit einem Beitrag aus den eidg. Arbeitsbeschaffungskrediten.     

用自身血清抗体筛选人肝细胞肝癌抗原

为了从分子水平上筛选肝细胞肝癌抗原，应用作者所在实验室创建的“重组克隆表达抗原的血清学鉴定技术”（ＳＥＲＥＸｓｅｒｏｌｏｇｉｃａｌｉｎｄｅｎｔｉｆｉｃａｔｉｏｎｏｆａｎｔｉｇｅｎｓｂｙｒｅｃｏｍｂｉｎａｎｔｅｘｐｒｅｓｉｏｎｃｌｏｎｉｎｇ）筛选人肝细胞肝癌（ＨＣＣ）组织构建的ｃＤＮＡ文库，发现了许多与病人，自身血清高滴度抗体反应的克隆。应用多种异体（其他ＨＣＣ病人，多种非ＨＣＣ肿瘤病人，Ｂ型、Ｃ型病毒性肝炎病人，肝硬化病人以及健康人）血清反应分析表明，高滴度抗体反应多数出现在ＨＣＣ病人。参照基因库寻找这些克隆的同源结构，发现其中许多抗原为至今未知基因所编码。进一步的血清和抗原分子分析将为ＨＣＣ特异免疫治疗和诊断提供基础资料     

Attosecond metrology.

The generation of ultrashort pulses is a key to exploring the dynamic behaviour of matter on ever-shorter timescales. Recent developments have pushed the duration of laser pulses close to its natural limit-the wave cycle, which lasts somewhat longer than one femtosecond (1 fs = 10-15 s) in the visible spectral range. Time-resolved measurements with these pulses are able to trace dynamics of molecular structure, but fail to capture electronic processes occurring on an attosecond (1 as = 10-18 s) timescale. Here we trace electronic dynamics with a time resolution of 相似文献   

管理复杂模型体系的面向对象方法

从面向对象方法基本原理和向面对象编程的技术特征出发，阐明所建应用软件系统中的模型对象、类及相应类层次结构和类组合结构，使系统具有表现真实世界复杂系统结构的能力。系统通过消息传递在模型程序执行中实现对操作的调用机制，使之在面向用户问题选择和执行求解策略方面有很强的适应性。这一点对于强调人机交互和解题协作的智能决策支持系统至关重要。给出了用Ｃ＋＋实现的模型对象系统及消息传递机制。     

两个双态噪声驱动系统的近似几率密度研究

研究了由两个双态噪声驱动的随机系统。给出了该随机系统的几率密度方程组，借助几率密度的随机刘维方程和对双态噪声变换，求得了近似几率密度方程。运用这种方法导出了随机的化学反应系统的近似几率密度方程。利用“Ｈａｎｇｇｉ－ｌｉｋｅａｎｓａｔｚ”求得了此化学反应的近似Ｆｏｋｋｅｒ－ｐｌａｎｃｋ方程及其定态解。     

大斜视角SAR成像的改进频率变标算法

首先给出了一种改进的频率变标算法。该算法适用于处理距离解线调后的聚束式SAR数据。对大斜視角数据,由于二次距离压缩误差的影响,偏离参考距离的散射点未能完全聚焦,且离参考距离越远聚焦性能越差。将非线性变标的方法加入频率变标算法对数据进行二次距离压缩,有效地减小了距离压缩误差。最后通过仿真实验表明,对给定的SAR参数,在斜视角为定值时,也能得到较好的成像结果。     

Initial corrosion observed on the atomic scale

Corrosion destroys more than three per cent of the world's GDP. Recently, the electrochemical decomposition of metal alloys has been more productively harnessed to produce porous materials with diverse technological potential. High-resolution insight into structure formation during electrocorrosion is a prerequisite for an atomistic understanding and control of such electrochemical surface processes. Here we report atomic-scale observations of the initial stages of corrosion of a Cu3Au111 single crystal alloy within a sulphuric acid solution. We monitor, by in situ X-ray diffraction with picometre-scale resolution, the structure and chemical composition of the electrolyte/alloy interface as the material decomposes. We reveal the microscopic structural changes associated with a general passivation phenomenon of which the origin has been hitherto unclear. We observe the formation of a gold-enriched single-crystal layer that is two to three monolayers thick, and has an unexpected inverted (CBA-) stacking sequence. At higher potentials, we find that this protective passivation layer dewets and pure gold islands are formed; such structures form the templates for the growth of nanoporous metals. Our experiments are carried out on a model single-crystal system. However, the insights should equally apply within a crystalline grain of an associated polycrystalline electrode fabricated from many other alloys exhibiting a large difference in the standard potential of their constituents, such as stainless steel (see ref. 5 for example) or alloys used for marine applications, such as CuZn or CuAl.