Numerical simulation of C/C/C planar X-ray waveguides.

A numerical simulation was done to check the possibility of using planar C/C/C multilayers with density contrast 0.2 and 0.7 g/cm3 as an X-ray waveguide. After an optimization procedure, suitable waveguide layer thicknesses were found which provide a high degree of resonant standing wave field intensity enhancement in the core layer at incident beam energy of 13 keV. The obtained results were compared with those of the Mo/Be/Mo waveguide, whose high waveguiding capability at the same energy value was reported in the 1990s. The comparison shows that standing wave field intensity resonant enhancement provided by C/C/C planar multilayers is very high and, consequently, a guided beam can be well detected.     

C45- und C50-Carotinoide. 5. Mitteilung

C₄₅- and C₅₀-Carotenoids. Synthesis of an Optically Active Cyclic C₂₀-Building Block and of (2R,2′S)-3′,4′-Didehydro-1′,2′-dihydro-2-(4-hydroxy-3-methylbut-2-enyl)-2′-(3-methylbut-2-enyl)-β,ψ-caroten-1′-ol (= C. p. 473) The synthesis of the optically active C₂₀-building block (R)- 16 and of the optically active C₅₀-carotenoid C.p. 473 ( 1 ) starting from (?)-β-pinene is reported.     

选相示波伏安法

选相示波伏安法毕树平，都思丹，高鸿（南京大学化学系，２１０００８）关键词示波计时电位法，选相示波伏安法，切口示波计时电位法是利用ｄＥ／ｄｔ～Ｅ曲线上切口的高度或深度进行定量分析的方法［１］，但由于ｄＥ／ｄｔ曲线主要反映充电电流的变化，从而使该方法的检...     

Triterpenoid saponins from Ilex mamillata C.Y. Wu ex C.J. Tseng

Two new triterpenoid saponins, ilemaminosides A and B (1 and 2) along with six known saponins (3-8) were isolated from 70% ethanolic extract of the leaves of Ilex mamillata C.Y. Wu ex C.J. Tseng. The new saponins were characterised as 3-O-α-L-arabinopyranosyl-ilexgenin B (1) and 3-O-β-D-glucopyranosyl-(1?→?3)-α-L-arabinopyranosyl-ilexgenin B (2). The structures of compounds 1 and 2 were elucidated on the basis of the chemical and spectroscopic methods, and the structures of known compounds were identified by comparison of their spectroscopic data with those reported in the literature. The compounds showed inhibitory activities in anti-inflammatory assay in?vitro with IC(50) values in the range 25.37-38.33?μg?mL(-1).     

Separation of phenotypically indistinguishable Candida species, C. orthopsilosis, C. metapsilosis and C. parapsilosis, by capillary electromigration techniques

At the current state of laboratory diagnostics, methods for fast identification of phenotypically indistinguishable species are difficult or inaccurate. An example is represented by Candida parapsilosis, which is the second most common yeast species isolated from bloodstream infections. C. parapsilosis comprises a complex of three genetically distinct groups. Genotypes II and III have been designated as the separate species Candida orthopsilosis and Candida metapsilosis, phenotypically indistinguishable. The considerable genetic variability of these newly described yeasts species has caused difficulties in the development of molecular techniques for their precise identification. Similarly, the detection of biofilm formation, which is considered as an important yeast virulence factor, is accompanied by difficulties. In this study we optimize the first precise and reproducible method for the separation and possible identification of C. orthopsilosis, C. metapsilosis and C. parapsilosis as well as the detection of their ability to form biofilm. The method is based on capillary isoelectric focusing and capillary electrophoresis with UV detection. In capillary isoelectric focusing, very narrow pH gradients were established. With such gradients, differences in isoelectric points of biofilm-negative and biofilm-positive species calculated from the migration times of the selected pI markers were below 0.03 pI units. In the capillary zone electrophoresis narrow zones of the cells of Candida species were detected with sufficient resolution. The values of the isoelectric point and the migration velocities of the examined species were independent on the origin of the tested strains. Capillary isoelectric focusing was examined also for the separation and detection of the cultivated biofilm-negative C. parapsilosis in the blood serum.     

C45- und C50-Carotinoide. 2. Mitteilung. Synthese von optisch aktiven acyclischen C15-Endgruppen

C₄₅- and C₅₀-Carotenoids. Synthesis of Optically Active Acyclic C₁₅-End Groups The optically active C₁₅-end groups (S)- 12 , (S)- 13 and (R)- 14 were prepared from the C₁₂-synthon (S)- 11 in good chemical and optical yield. These C₁₅-end groups are suitable compounds for the synthesis of optically active C₄₅- and C₅₀-carotenoids.