Semiquantitative Analysis of Solid Surfaces by X-Ray Photoelectron Spectroscopy(Chemistry)

An application of the equation (1) to the semiquantitative analysis of solid surface by X-ray photoelectron spectroscopy were performed. chemical formula……(1) Where n is the concentration of the element in terms of atoms per unit volume, N is the intensity of ejected photoelectrons, σ is the photoionization cross section, λ is the mean free path for photoelectron in the sample, and S is the spectrometer (sensitivity) factor. The atomic ratios of oxygen to metal element in some oxides could be obtained with satisfactory results by the application of theoretical values of photoionization cross sections and mean free paths. In this case the summation of main and satellite peak intensities were employed for the calculation. Furthermore the atomic ratio of metallic state elements, oxide state ones and oxygen on copper-nickel alloy surface and surface enrichment of nitrogen and sulfur on iron surface were discussed

On the Surface Chemical Reactions of Metal and Oxide XPS Samples at 300-400°at a High Vacuum Produced by Oil Diffusion Pumps(Chemistry)

Metal and oxide surface reactions formed by heating in the spectrometer at 300-400° at a vacuum of ca. 10^ Torr (oil diffusion pumps) were studied. As a result of spectral observations before and after heating, the metals studied were classified into five groups. In the first group, oxide films on the metal surface are easily evaporated because of the high vapour pressure of oxide ; in the second, the oxide films are easily reduced in the spectrometer ; in the thrid, the oxide film formed on the metal is reduced but the bulk oxide is not easily reduced ; in the fourth, very stable oxide films are formed and the bulk oxide is also stable ; and finally in the fifth, the oxide film formed on the metal is apparently reduced, yet the bulk oxide is very stable

Quantitative monitoring of single nucleotide mutations by allele-specific quantitative PCR can be used for the assessment of minimal residual disease in patients with hematological malignancies throughout their clinical course

BackgroundMonitoring of minimal residual disease (MRD) in patients with hematological malignancies is important for evaluating the patients\u27 therapeutic response and risk of relapse. Single nucleotide mutations associated with leukemogenesis can be considered as applicable MRD markers.MethodsWe developed an allele-specific quantitative polymerase chain reaction (AS-qPCR) for FLT3 2503G > T, KIT 2446G > T, and KIT 2447A > T and compared the change in the expression levels of the FLT3 or KIT mutations assessed by AS-qPCR to those of the RUNX1–RUNX1T1 fusion gene and WT1 by conventional quantitative PCR.ResultsThe AS-qPCR using primers including template-mismatched nucleotide or template-mismatched nucleotide plus locked nucleic acid substituted nucleotide provided higher selectivity for mutant nucleotides. The change in the expression levels of the FLT3 or KIT mutations at the time of relapse and just after hematopoietic stem cell transplantation correlated well with that of the RUNX1–RUNX1T1 fusion gene and WT1. Moreover, during complete remission, only AS-qPCR could detect low-level expression of residual mutations.ConclusionsThe AS-qPCR for analyzing single nucleotide mutations contributes to the monitoring of MRD in patients without recurrent fusion gene throughout the clinical course and thus broadens the spectrum of patients in whom MRD can be monitored

光電界センサを用いたレーザによる放電誘導機構の解明

It is very important to clarify the mechanism of discharge induced by a laser-produced plasma channel as a basic study on the laser-induced lightning. We measured the temporal evolution of the electron density and the neutral particle density in one of plasma beads in the channel using Thomson and Rayleigh scattering methods, and also performed discharge induction experiments for a short gap. It was found that the induced discharge is greatly influenced by the temporal evolution of the electron density and the neutral particle density in a plasma. In this paper, we measured the electric field along the channel using an optical sensor at the discharge induction to study the leader propagation process in a long gap. The induced discharge in a long gap changes in the order of electron avalanche, streamer, leader, and final sparkover similarly as in a long gap discharge in the atmosphere. To clarify the leader propagation, we measured the change in the electric field due to the leader propagation between the electrodes, and estimated the velocity of the leader propagation. The electric field was measured using an optical sensor based on the Pockels effect