Triple quad ICPMS (ICPQQQ) as a new tool for absolute quantitative proteomics and phosphoproteomics

It is clear that sensitive and interference-free quantification of ICP-detectable elements naturally present in proteins will boost the role of ICPMS in proteomics. In this study, a completely new way of polyatomic interference removal in ICPMS for detection of sulfur (present in the majority of proteins as methionine or cysteine) and phosphorus (present in phosphorylated proteins) is presented. It is based on the concept of tandem mass spectrometry (QQQ) typically used in molecular MS. Briefly, the first quadrupole can be operated as 1 amu window band-pass mass filter to select target analyte ions ((31)P, (32)S, and their on-mass polyatomic interferences). In this way, only selected ions enter the cell and react with O(2), reducing the interferences produced by matrix ions as well as background noise. After optimization of the cell conditions, product ions formed for the targets, (47)PO(+) and (48)SO(+), could be detected with enhanced sensitivity and selectivity. The coupling to capillary HPLC allowed analysis of S- and P-containing species with the lowest detection limits ever published (11 and 6.6 fmol, respectively). The potential of the approach for proteomics studies was demonstrated for the highly sensitive simultaneous absolute quantification of different S-containing peptides and phosphopeptides.     

纳米微粒与LCD:一个令人惊奇的世界

把纳米微粒加进液晶显示器(LCD)的主要媒介之中,将引发液晶材料几乎所有的物理性能发生改变,导致工作电压和响应时间均下降。这种技术可能是不需要进行化学分析来提高液晶材料性能的备选方案。     

Study on the breaking behavior of self-bursting microcapsules

We have successfully prepared “self-bursting” microcapsule. The microcapsule retains its shape when suspended in water but breaks open quickly after the water evaporates. In this report, the breaking behavior of MC, which encapsulated insecticide (pyriproxyfen) with polyurethane via an interfacial polymerization method, was studied. In order to investigate the self-bursting phenomenon more detail, we studied the relationships between the self-burst ratio and the self-weight of the microcapsule, capillary force, and critical buckling stress. As a result, it was found that wall thickness affected the self-bursting phenomenon.     

Measurement of deuterium and helium by glow-discharge optical emission spectroscopy for plasma–surface interaction studies

To examine the resolution of isotope analysis of hydrogen with glow-discharge optical emission spectroscopy (GDOES), depth profiles of hydrogen and deuterium in a H-containing Ta/D-containing Ti/Ni layered structure were measured. The depth profiles of deuterium could be measured with sufficient resolution in the presence of relatively large amounts of hydrogen and vice versa. In addition, measurements of depth profiles of He implanted in W at room temperature were also performed with Ne plasma. The intensity of the He emissions was sufficiently high at a fluence of 10²⁰ He m^?2 or higher. The depth profiles of He measured in this manner were in good agreement with the results of cross-sectional observations using a transmission electron microscope. Therefore, it was concluded that GDOES with Ne plasma is a promising technique for the depth profile analysis of plasma-facing materials and deposited layers formed on them.     

Electrical and magnetic properties of electro-oxidative polymerized poly(tris(thienylphenyl)amine)s

Electro-oxidative polymerized poly(tris(thienylphenyl)amine)s, which have the hyperbranched (dendritic) structure (PTPA) and linear type (PMeTPA), were investigated for their electrical and magnetic properties. The conductivity PTPA showed was almost one order higher than that of PMeTPA. From the solid state ESR measurements of the polymers, observation of ESR signal at g = 2.0027 and 2.0030 indicated the formation of a triphenylamine cation radical. The normalized magnetization plots (M/M_s) for PTPA and PMeTPA are close to the theoretical Brillouin curves for S = 1, indicating a magnetic interaction between the spin centers in PMeTPA. The spin concentrations determined by the M_s values of PTPA and PMeTPA were 7.3–7.4 and 1.3–1.4%, respectively. This large difference in the spin concentration of the polymers according to the structure resulted from a different spin conformation by the radical structure.     

Effects of Solidification Conditions on Grain Refinement Capacity of TiC in Directionally Solidified Ti6Al4V Alloy

In this study, the effects of solidification conditions on the grain refinement capacity of heterogeneous nuclei TiC in directionally solidified Ti6Al4V alloy were investigated using experimental and numerical approaches. Ti6Al4V powder with and without TiC particles in a Ti6Al4V sheath was melted and directionally solidified at various solidification rates via the floating zone melting method. In addition, by using the phase field method, the microstructural evolution of directionally solidified Ti6Al4V was simulated by varying the temperature gradient G and solidification rate V. As the solidification rate increased, the increment of the prior β grain number by TiC addition also increased. There are two reasons for this: first, the amount of residual potent heterogeneous nuclei TiC is larger. Second, the amount of TiC particles that can nucleate becomes larger. This is because increasing the constitutional undercooling ΔT_c leads to the activation of a smaller radius of heterogeneous nuclei and a higher nucleation probability from each radius. At a cooling rate R higher than that in the floating zone melting experiment (R = 3 to 1000 K/s), the maximum degree of constitutional undercooling ΔT_c,Max has a peak value, which suggests that constitutional undercooling ΔT_c has a smaller contribution at higher cooling rates, such as those that occur during electron beam melting (EBM), including laser powder bed fusion (LPBF).

     

Corrosion resistance of a cast steel overpack for high-level radioactive waste disposal in Japan

The corrosion rate and stress corrosion cracking (SCC) susceptibility of a cast steel are studied for its application to metal containers (namely overpacks) for geological disposal of high-level radioactive waste. Specimens for corrosion tests are cut from a prototype overpack manufactured by full-scale casting. Casting defects are widely distributed in the prototype overpack; however, the flat-bottom hole equivalent diameters for all defects detected by an ultrasonic test are 3.6 mm or less, which is relatively small. Forged steels and rolled steels are also tested for comparison of their corrosion properties with the cast steel. The corrosion rates are obtained by immersion tests in bentonite saturated with synthetic seawater under anaerobic conditions at 80°C for up to 1 year. The corrosion rate for the cast steel calculated by the weight loss during the experiments is close to that for the forged steels and rolled steels. The SCC susceptibility is examined using slow strain rate tests in a 1.5-mol L⁻¹ carbonate–bicarbonate solution, in which the occurrence of high-pH SCC is often reported for carbon steels. The SCC susceptibility increased with the increase in the carbon content of the products; however, there are no clear differences between casting and forging.     

Convergence analysis of MOC inner iterations with large negative self-scattering cross-section

When the transport correction is applied to the total cross-section, the self-scattering cross-section could have a negative value in order to preserve the balance of partial cross-sections. The negative self-scattering cross-section may lead to a negative impact on the convergence behavior for the method of characteristics (MOC), especially in a problem with large moderator regions containing hydrogen. In order to address this issue, the spectral radius of the inner iteration of MOC is theoretically estimated for various self-scattering cross-sections. It is found that the spectral radius of the inner iteration of MOC could exceed unity for a large negative self-scattering cross-section, which results in numerical divergence. A countermeasure for the divergence using the successive over relaxation method is also discussed in this paper.     

Effect of grain boundary cracks on the corrosion behaviour of aluminium titanate ceramics in a molten aluminium alloy

The effect of grain boundary cracks on the corrosion behaviour of non-doped aluminium titanate (AT) ceramics was evaluated in a molten Al alloy containing a slight amount of Mg. The corrosion of AT ceramics, in which the AT grains decomposed and subsequently reacted with liquid and/or gaseous Mg to produce MgAl₂O₄, proceeded not only on sample surfaces in contact and non-contact with the melt, but also on open grain boundary crack surfaces in the ceramic interior. Therefore, the corrosion resistance of AT ceramics can be improved by control of their grain size to close open cracks in the molten alloys.