Aptasensor for Thrombin Based on Carbon Nanotubes‐Methylene Blue Composites

The amperometric and EQCM aptasensors based on DNA aptamers immobilized by avidin‐biotin method or by electrostatic adsorption onto multiwalled carbon nanotube layer contained methylene blue (MB) have been developed and examined for thrombin detection in buffer and in spiked blood serum. The presence of MB increases the binding capacity of the surface layer and enhances the range of thrombin concentrations to be determined. This results in significant improvement of analytical characteristics of thrombin detection. The EQCM aptasensors allowed us to detect 0.3–100 nM and amperometric aptasensors 10–1000 nM of thrombin.     

Anisotropy of the spatial distribution of CO molecules desorbing from tungsten

The desorption of CO from an anisotropic surface of polycrystalline tungsten after different periods of annealing has been studied. Anisotropy in the spatial distribution of CO molecules in the desorbing flux was detected at early stages of annealing. Smoothing out of the surface texture during annealing recorded by means of STM resulted in the disappearance of the spatial distribution anisotropy. The results are quantitatively explained by the model of a rough surface.⁷ Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 999–1002, June, 1994.The authors express their profound gratitude to Prof. V. I. Panov and his collaborators for making it possible to carry out measurements with a tunneling microscope and for their help.     

Spectral characteristics of sealed CO lasers with various isotope concentrations and room temperature cooling

The spectral and power characteristics of sealed CO lasers with differing isotopes and room temperature cooling are reported.     

From the Cube to the Dyck and Klein Tessellations: Implications for the Structures of Zeolite-like Carbon and Boron Nitride Allotropes

Geometrical transformations can be described which have the effect of multiplying the numbers of vertices in a trivalent polyhedron by three, four, or seven. Tripling the cube by the so-called leapfrog transformation gives the truncated octahedron. Quadrupling the cube followed by identifying the square faces to give a genus 3 surface gives the Dyck surface of 12 octagons. Septupling the cube by the so-called capra transformation followed by identifying the square faces to give a genus 3 surface gives the Klein surface of 24 heptagons. These geometrical transformations relate to the construction of low-density zeolite-like structures for carbon and boron nitride allotropes based on a cubic lattice     

A new,improved sensor for ascorbate determination at copper hexacyanoferrate modified carbon film electrodes

A new, improved sensor for the electrocatalytic determination of ascorbate has been developed that has both a low applied operating potential and a low detection limit. The sensor was constructed by depositing copper hexacyanoferrate film either electrochemically or chemically onto carbon film electrode, and it was then characterised by cyclic voltammetry and electrochemical impedance spectroscopy. Chemically deposited films were shown to be the best for ascorbate determination and were used as an amperometric sensor at +0.05 V versus SCE to determine ascorbate in wines and juice. The linear range extended to 5 mM with a limit of detection of 2.1 M, the sensor was stable for more than four months, and it could be used continuously for at least 20 days.     

Reaction kinetic behavior of different carbon monoxide adspecies on palladium-alumina during oxidation: an in-situ IR study

Carbon monoxide oxidation on Pd(10 w.t.%)-alumina was studied by in-situ infrared spectroscopy. It was found that the oxidation reactivities vary with different CO adspecies: linear COad > 2-fold bridged COad > multi-bridged COad.     

HT20—40铸铁中碳的光电光谱分析

本文主要论述HT20-40铸铁中碳的光电光谱分析。由于薄片样急冷快,白口化好,这样解决了铸铁样品难以白口化的问题。为了加工薄片样,设计了磁钢磨具。解决了加工薄片样非常困难的问题。实践证明,只要严格控制铸铁样分析条件,碳的光电光谱分析结果完全达到了要求。     

一氧化碳血红蛋白的一阶导数光谱测定法

研究血液中碳氧血红蛋白浓度在连二亚硫酸钠还原前后导数光谱的变化,建立血液中碳氧血红蛋白的565nm一阶导数光谱定量测定方法。方法在0—100%范围内线性关系良好,不同浓度的平均回收率99.9%。结果表明,本方法准确快速、结果令人满意。