The regioselectivity of the formation of 2-pyrazolylthiazoles and their precursors from the reaction of 2-hydrazinothiazoles with 4,4,4-trifluoro-1-hetaryl-1,3-butanediones

Reaction of 2-hydrazinothiazoles 1 with 1-thienyl- and 1-furyl-1,3-butanediones 2a,b in methanol in the presence of hydrochloric acid mainly leads to a mixture of pyrazoles 3 and pyrazolines 4 or pyrazoles 3 and 5 in strong acidic conditions. Isomeric hydrazones 6 and pyrazolines 4 were formed and isolated in these reactions in the absence of hydrochloric acid. It has been shown that the regioselectivity in the reaction of diketones 2 with hydrazine 1 is governed by both the concentration of acid and the nature of substituents in the 1,3-diketones 2. Cyclization of hydrazones 6 is shown to occur under milder conditions than dehydration for pyrazolines 4. The new heterocyclic compounds were prepared and fully characterized by NMR spectra and by X-ray analysis for 3c.     

Antibody synthesis induced by endogenous internal images

In this study, immunization with a vaccine consisting of multiple F(abt’)₂ fragments of affinity-purified antitetanus toxoid antibodies covalently bound to a carrier protein successfully induced antitetanus toxoid antibodies. Further studies showed that this vaccine preparation contained no biologically detectable tetanus antigen. The induced antitetanus antibody (Ab1t’) titer was higher than the titer of antibodies binding control antigens. The immunizing F(abt’)₂ preparation did not elicit a secondary antitetanus response from mice primed with tetanus toxoid and, hence, appeared free of tetanus epitopes. The specificity of Ab1t’ was established by absorption and inhibition with antigen. Immunization with antitetanus F(abt’)₂ (Ab1t’) fragments appears to have elicited naturally occurring autologous antitetanus toxoid antibody (Ab1t’) through an idiotypic pathway. As predicted by network theory, anti-idiotype (Ab2) and antitetanus (Ab1t’) cycled reciprocally. Clonotypic characterization of Ab1t’ using isoelectric focusing and affinity immunoblotting showed increases in Ab1t’ titer to be the result of increased synthesis by limited subsets of antitetanus toxoid B-cell clones and not increased synthesis by multiple clones, as is characteristic of antigen-driven Ab1 responses. Many Ab1 and Ab1t’ clonotypes had identical pIs, suggesting that they either share V region genes or are the product of the same B-cell clones. These findings indicate that immunization with polyclonal multivalent Ab1 preparations can trigger active synthesis of antibodies with the same specificity. The results provide further evidence for naturally occurring idiotypic cascades that could be exploited for studies of catalytic antibodies.     

水溶性金属卟啉肿瘤靶向磁共振成像造影剂的研究

利用显微荧光－阿达玛变换三维图像分析研究了Ｃｕ－ＴＳＰＰ，Ｍｎ－ＴＳＰＰ，Ｃｕ－ＴＭＡＰ，Ｍｎ－ＴＭＡＰ４种水溶性金属卟啉人细胞间质进入肿瘤细胞内的富集过程，对金属卟啉的自旋－晶格驰豫性能（Ｒ１）的天空结果表明，Ｍｎ（Ⅱ）卟啉配合物的Ｒ１、值结Ｇｄ－ＤＴＰＡ提高１．５－２倍。     

Real‐time lock‐in energy loss imaging with a novel high‐speed image processing CCD video camera

We have developed a high‐speed image processing CCD video camera for real‐time energy‐loss imaging using a conventional electron microscope with an energy‐loss imaging facility. As an initial demonstration of real‐time lock‐in energy‐loss imaging, a background‐subtracted energy‐loss image was observed by attaching the high‐speed image processing CCD video camera to an analytical electron microscope equipped with a floating‐type energy‐loss imaging analyser. Copyright © 2003 John Wiley & Sons, Ltd.     

Oxidation products of the niobium tungsten oxide Nb4W13O47: A high-resolution scanning transmission electron microscopy study

Nb₄W₁₃O₄₇, a member of the solid solution series Nb_8−nW_9+nO₄₇ (0?n?5), crystallizes in a threefold superstructure of the tetragonal tungsten bronze structure. While the oxidation of this reduced phase at T_OX=1200 °C leads to a separation into the thermodynamically stable phases, lower oxidation temperatures result in products that comprise new structural elements and ordering variants. The characterization of the oxidation products obtained at T_OX=1000 °C was performed by scanning transmission electron microscopy applying a high-angle annular dark field detector. At the selected imaging conditions (Z contrast), not only the metal positions are revealed by this technique but valuable additional information about the elemental distribution can be obtained simultaneously.     

纳米分辨率的三维形貌检测仪

从光干涉方式，瞳窗关系和光源带宽等基本关系出发，利用空间不变系统理论解析了相移显微干涉检测系统中衍射效应的影响。为了减小横向分辨率对纵向分辨率的影响，利用相关信息提取或数字滤波的方法，获得了纳米分辨率的三维形貌。     

Molecular structure and spectral properties of thionaphthalimides

The molecular structure and absorption spectra of monothio- and dithio-naphthalimides were compared to their naphthalimide analogues using AM1, PM3 and ZINDO/S semiempirical quantum chemical methods. The substitution of the 4R-naphthalimide oxygen atoms by sulphur atoms resulted in a red-shift of the absorption spectra by Δλ_max60-65 and 100-140 nm, respectively. The thionated naphthalimide derivatives do not show observable fluorescence due to intersystem crossing to the triplet -states localised at the CS groups. The -absorption bands of monothioimides are located at 525-580 nm (ε=60-80) and those for dithioimides at 535-560 nm (ε=140-390) and 628-686 nm (ε=34-68). None of these transitions are solvent sensitive. The -transitions of N-phenylthioimides have also a small contribution from -states due to a partial conjugation between CS group and π-electronic system of the N-phenyl ring. As a result, the bands of aromatic substituted N-phenylthioimides are red-shifted as compared to those of the aliphatic N-methyl-thioimides.     

图像通信业务的现状与发展方向

阐述了图像通信的业务涵盖范围及其技术发展现状，简要介绍了图像通信的发展方向，指出了图像通信产业发展面临的研究课题。     

贝叶斯融合在SAR图像分类中的应用

本文研究将数据融合理论用于SAR图像分类.通过贝叶斯理论进行多通道SAR图像测量级数据融合,充分利用像素的从属信息并获得单通道分类无法获取的分类结果,有效保留各通道有用信息并抑制图像中的斑点噪声;针对贝叶斯融合涉及到的先验概率的问题采用两种方式进行先验概率估计,对估计引起的马赛克现象提出了三种解决方法;并提出三种先验概率融合方法,比较得出相对最优的SAR图像多通道分类方案.