Improving Beamline X-ray Optics by Analyzing the Damage to Crystallographic Structure

The mission of the X-ray Characterization Laboratory in the X-ray Science Division (XSD) at the Advanced Photon Source (APS) is to support both the users and the Optics Fabrication Facility that produces high-performance optics for synchrotron X-ray beamlines. The Topography Test Unit (TTU) in the X-ray Lab has been successfully used to characterize diffracting crystals and test monochromators by quantifying residual surface stresses. This topographic method has also been adapted for testing standard X-ray mirrors, characterizing concave crystal optics and, in principle, can be used to visualize residual stresses on any optic made from single crystalline material.     

Electrochemical and Biological Studies on Reactivity of [VO(oda)(H2O)2], [Co(oda)(H2O)2]·H2O,and [Ni(oda)­(H2O)3]·1.5H2O Towards Superoxide Free Radicals

The reactivity of superoxide free radicals (O₂ ^{· –}) generated electrochemically towards the oxydiacetate metal complexes, namely [VO(oda)(H₂O)₂], [Co(oda)(H₂O)₂] · H₂O, and [Ni(oda)(H₂O)₃] · 1.5H₂O (oda = oxydiacetate) was examined by cyclic voltammetry. The measurements were carried out in DMSO solution using a platinum electrode. Based on the height of the anodic peak E_a that corresponds to electrochemical oxidation O₂ ^{· –} → O₂ + e, in the absence and in the presence of the compounds in the mixture, their O₂ ^{· –} scavenge ability was assessed. The influence of the type of the complex was briefly discussed. H₂O₂ was used to induce cellular injury in a mouse hippocampal cell line (HT22). The cytoprotection of chemical compounds was tested at the mitochondrial (MTT test) and plasma membrane level (LDH leakage). Dose‐dependent effect (10 and 100 μM of the complex) of investigated compounds was observed.     

Detection of Prunus Necrotic Ringspot Virus in Plant Extracts with Impedimetric Immunosensor based on Glassy Carbon Electrode

This paper concerns the development of an immunosensor for detection of Prunus necrotic ringspot virus (PNRSV) in plant extracts. The immunosensor fabrication consists of successive modification steps of glassy carbon electrodes: (i) creation of COOH groups, (ii) covalent immobilization of protein A with EDC/NHS coupling reaction, (iii) immobilization of anti‐PNRSV IgG polyclonal antibody, (iiii) filling free spaces with BSA. Each step was controlled with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The immunosensor was applied for the determination of the PNRSV virus in extracts from cucumber leaves using EIS technique. It was capable of discriminating between samples consisting of extracts from healthy plants and consisting of leaf extracts from infected plants diluted 10 000 times with extract from healthy plants.