Quantitative analysis of oxide films on ODS-alloys using MCs+-SIMS and e-beam SNMS

Summary Attempts to obtain a quantitative analysis of depth profiles of oxide films on iron-based ODS-alloys using MCs⁺-SIMS and e-beam SNMS are presented. Since the oxide films of the alloys consist mainly of alumina, implantation standards in Al₂O₃(sapphire) were used for the quantification of the measured depth profiles. The so-called matrix effect, normally present in SIMS analysis, is strongly reduced by recording the MCs⁺-secondary ions. Over a wide concentration range, agreement between SIMS and SNMS data is obtained within a factor 2–3. The evaluated concentration profiles for the main alloying elements in combination with ¹⁸O tracer-experiments have been used to give an interpretation of the growth processes of the oxide films for Fe-based ODS-alloys, with and without the addition of an yttria dispersion. The results show that the addition of yttria dispersion is responsible for the dramatic change observed in the oxide growth mechanism.ODS=Oxide Dispersion strengthenedThis poster was awarded the First Prize in Poster Session A by the Deutscher Arbeitskreis für Spektroskopie (DASp)     

New trends in methodological developments in clinical chemistry

Many new techniques have been introduced in clinical chemistry. Three important new methodologies are dry chemistry, gen technology and biosensors. Solid-phase chemistry systems. The two most common solid-phase systems are the Kodak-Ektachem and the Boehringer Mannheim Reflotron. The first one is working with serum and the second one mainly with whole blood. The determination of urea and the determination of the activity of AST (GOT) will be described. The greatest problems of these systems are the quality control of the analysis and the interferences by endogenous and exogenous substances. Analysis with the aid of gen technology. The major diagnostic applications of gen technology in human disease is the detection of genetic disorders and the tumor diagnosis. The beta-thalassemia will be the example for genetic disorders and the chronic myeloid leukemia (CML) for diagnosis of a tumor. Thalassemias are a group of inherited disorders caused by the defective or absent outpout of one of the globin chains of the Hb tetramere. The CML is an example of a specific translocation of a small region of chromosome 9 bearing the abl-oncogene to chromosome 22. Biosensors in biochemical analysis. Biosensors are analytical devices that respond selectively to analytes in an appropriate sample and convert their concentration into an electrical signal. As examples an in-vivo ferrocene-mediated glucose sensor and the determination of the isoenzyme LDH5 based on an antigene-antibody reaction are described.     

Synthesis of New Potential NMDA Antagonist Based on Acylphosphonate Derivatives

Abstract

In recent years intensive pharmacological research is focused on the N-methyl-D-aspartate (NMDA) receptor, which has been implicated in normal neuronal hnctioning, including excitatory synaptic transmission, as well as in the pathologies of the central nervous system such epilepsy, Alzheimer and Parkinson's disease, and neurodegeneration following a stroke.     

Biodegradability screening of soil amendments through coupling of wavelength‐scanned cavity ring‐down spectroscopy to multiple dynamic chambers

A system was developed for the automatic measurements of ¹³CO₂ efflux to determine biodegradation of extra carbon amendments to soils. The system combines wavelength‐scanned cavity ring down laser spectroscopy (WS‐CRDS) with the open‐dynamic chamber (ODC) method. The WS‐CRDS instrument and a batch of 24 ODC are coupled via microprocessor‐controlled valves. Determination of the biodegradation requires a known δ¹³C value and the applied mass of the carbon compounds, and the biodegradation is calculated based on the ¹³CO₂ mixing ratio (ppm) sampled from the headspace of the chambers. The WS‐CRDS system provided accurate detection based on parallel samples of three standard gases (¹³CO₂ of 2, 11 and 22 ppm) that were measured simultaneously by isotope ratio mass spectrometry (linear regression R² = 0.99). Repeated checking with the same standards showed that the WS‐CRDS system showed no drift over seven months. The applicability of the ODC was checked against the closed static chamber (CSC) method using the rapid biodegradation of cane sugar – δ¹³C‐labeled through C4 photosynthesis. There was no significant difference between the results from 7‐min ODC and 120‐min CSC measurements. Further, a test using samples of either cane sugar (C4) or beetroot sugar (C3) mixed into standard soil proved the target functionality of the system, which is to identify the biodegradation of carbon sources with significantly different isotopic signatures. Copyright © 2011 John Wiley & Sons, Ltd.     

Quasi-Static and Dynamic Behavior of Saturated Porous Media with Incompressible Constituents

In this paper the field equations governing the dynamic response of a fluid-saturated elastic porous medium are analyzed and built up for the study of quasi-static and dynamical problems like the consolidation problem and wave propagation. The two constituents are assumed to be incompressible. A numerical solution is derived by means of the standard Galerkin procedure and the finite element method.     

Determination of the pion charge form factor at Q2=1.60 and 2.45 (GeV/c)2

The 1H(e,e'pi+)n cross section was measured at four-momentum transfers of Q2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F(pi)) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which F(pi) is a free parameter. The results indicate that the pion form factor deviates from the charge-radius constrained monopole form at these values of Q2 by one sigma, but is still far from its perturbative quantum chromodynamics prediction.