Die Einwirkung von Schwefelnatrium auf freies, festes Jod und Jod in w?sseriger L?sung und Anwendung dieser Reaktion in der Analyse

Ohne Zusammenfassung     

Über Carbonyl-bis-aminosäuren und deren Umwandlungsprodukte II

Ohne Zusammenfassung     

Study of potential curves by UHF-type methods. VI. Spin-extended Hartree–Fock method

An improved computational procedure of the spin-extended Hartree–Fock method is presented. The main features of the EHF potential curves for the dissociation of the LiH, BeH, and Li₂ molecules are discussed. The results are compared with curves calculated by the perturbation or CI methods using the same basis set.     

人工神经元网络法提高毛细管电泳药物控制分析准确度的研究

研究了人工神经元网络法在毛细管电泳定量测定memantine中提高测定准确度 的可行性。在毛细管电泳法定量测定memantine的过程中，其浓度与峰高或峰面积 以及与二者和内标的比值均没有良好的线性关系。人工神经元网络具有很强的非线 性校正能力，其最大优点是无须对分离体系及组分的迁移行为预先予以了解。人工 神经元网络的输为memantine的峰高和峰面积，输出为memantine的浓度。通过实验 确定的网络结构为2：1：1型。由于人工神经元网络的通用性，该法也可用于毛细 管电泳在其他药物控制分析中改善定量分析的准确度。     

Reactivity of Hydroxy and Amino Derivatives of 2‐Phenyl‐1H‐imidazoline and 2‐Phenyl‐1H‐imidazole toward Isocyanates: Synthesis of Appropriate Carbamates and Ureas

Reactivity of 2‐(4‐hydroxyphenyl)‐1H‐imidazoline and 2‐(4‐hydroxyphenyl)‐1H‐imidazole toward substituted phenyl isocyanates was studied. When mentioned imidazoline was treated with 2.5 equiv of substituted phenyl isocyanate, three N,O‐dicarboxamides were prepared (substituents are H, 4‐NO₂, and 4‐CH₃). Subsequently, N,O‐diacetylated 2‐(4‐hydroxyphenyl)‐1H‐imidazoline was prepared and selective deprotection method was developed for preparation of 1‐acetyl‐2‐(4‐hydroxyphenyl)‐1H‐imidazoline using diethylamine in acetone. Six carbamates derived from this imidazoline were then prepared using 1.1 equiv of substituted phenyl isocyanates (substituents are H, 4‐CH₃, 4‐OCH₃, 4‐NO₂, 4‐CN, and 3‐CF₃). Finally, two carbamates were prepared from 2‐(4‐hydroxyphenyl)‐1H‐imidazole (substituents are 4‐NO₂ and 4‐CN). No reactivity to imidazole ring was observed in this case. Eight derivatives were subjected to antimycobacterial screening. Concurrently, reactivity of 2‐(2‐aminophenyl)‐ and 2‐(2‐hydroxyphenyl)‐1H‐imidazole toward aliphatic and aromatic isocyanates was studied. Eight ureas were prepared using equivalent mixture of 2‐(2‐aminophenyl)‐1H‐imidazole and isocyanate (Et, Pr, isoPr, terc‐Bu, Cy, Ph, 4‐CH₃C₆H₄, 4‐CNC₆H₄). Similar attempts to obtain related carbamates from 2‐(2‐hydroxyphenyl)‐1H‐imidazole lead only to three substituted phenyl carbamates (substituents are 4‐CH₃, 4‐NO₂, and 4‐CN). In both cases, no reactivity to imidazole ring was observed again.     

SPECTRAL CHARACTERIZATION OF MONOMERIC C-PHYCOERYTHRIN FROM PSEUDANABAENA W 1173 AND ITS α AND β SUBUNITS: ENERGY TRANSFER IN ISOLATED SUBUNITS AND C-PHYCOERYTHRIN

Abstract— Molecular weight determination by gel chromatography and analytical ultracentrifugation revealed that C-phycoerythrin from Pseudanabaena W 1173 exists as the monomer ∝βat a concentration up to 7μM and as the dimer (∝β)₂ at 40 μM. The purified subunits were monomeric species ∝ or β , respectively at 20 μM. Native monomeric C-phycoerythrin was compared with the renatured subunits in a number of spectral properties: absorption spectroscopy including determination of molar extinction coefficients, fluorescence emission and excitation at 293 and 4 K, and fluorescence polarization. Whereas spectra of denatured subunits and denatured C-phycoesythrin are identical, substantial changes occurred upon renaturation. Linear superposition of the absorption spectra of renatured subunits results in a curve identical with the absorption of native monomeric C-phycoerythrin.
The following conclusions were drawn: (a) Chromophore conformation is identical in renatured subunits and in native αβ monomer of C-phycoerythrin. (b) In C-phycoerythrin there are two fluorescing chromophores, degenerate in energy, one in the α - and the other in the β -subunit and three sensitizing chromophores which differ in their energies and spectral shapes, (c) The energy transfer in C-phycoerythrin occurs not only within but also between the subunits. (d) A weak fluorescence from sensitizing chromophores observed at low temperature (4 K) in the α -subunit and in C-phycoerythrin shows the limitations of the concept of sensitizing chromophores.
C-PE, C-phycoerythrin; P, degree of polarization; R, degree of anisotropy; SDS, sodium dode-cyl sulfate; s₂₀, sedimentation coefficient