Efficiency of visual peak detection in X‐ray photoelectron spectra

We report initial results of a VAMAS/TWA2 project to evaluate procedures for automated peak detection in X‐ray photoelectron spectra. As a reference for investigations of the efficiency of automated peak‐detection software, we report the efficiency of visual peak detection in three test spectra. It was found that (i) characteristics of analysts are grouped into four categories using principal component analysis (PCA); the first participant group to detect large numbers of peaks for the three test spectra, the second one to detect small numbers of peaks for them, the third one to detect similar numbers of peaks, and the fourth one to detect a relatively large number of peaks for one of them and small numbers for two of them, (ii) scattering of detected peak numbers seems to depend on detection of medium‐intensity peaks because of participants' subjectivity or ambivalence for judgment of intensity, and (iii) the peaks that are detected by the analysts with a detectability more than 75% almost correspond to the peak signal‐to‐noise(S/N) ratio of more than 10 in logarithmic expression. Copyright © 2008 John Wiley & Sons, Ltd.     

Predisposition of genetic disease by modestly decreased expression of GCH1 mutant allele

Recently it was shown that single nucleotide polymorphisms (SNPs) can explain individual variation because of the small changes of the gene expression level and that the 50% decreased expression of an allele might even lead to predisposition to cancer. In this study, we found that a decreased expression of an allele might cause predisposition to genetic disease. Dopa responsive dystonia (DRD) is a dominant disease caused by mutations in GCH1 gene. The sequence analysis of the GCH1 in a patient with typical DRD symptoms revealed two novel missense mutations instead of a single dominant mutation. Family members with either of the mutations did not have any symptoms of DRD. The expression level of a R198W mutant allele decreased to about 50%, suggesting that modestly decreased expression caused by an SNP should lead to predisposition of a genetic disease in susceptible individuals.     

Establishment of a microplate-formatted cell-based immunoassay for rapid analysis of nucleotide excision repair ability in human primary cells

DNA photolesions induced by UV, cyclobutane pyrimidine dimer (CPD) and (6-4) photoproduct (6-4PP), are repaired by nucleotide excision repair (NER) in human cells. Various immunoassays using monoclonal antibodies specific for the photolesions have been developed and widely used for the analysis of cellular NER activity. In this study, we have newly developed a microplate-formatted cell-based immunoassay, based on indirect immunofluorescence staining with lesion-specific antibodies combined with an infrared imaging system. Using this assay, we show the repair kinetics of CPD and 6-4PP in various fibroblasts from newborn and adult donors with no age-related difference. Furthermore, epidermal keratinocytes and melanocytes exhibit comparable NER activity, and calcium ion-induced differentiation of keratinocytes has no significant impacts on their NER activity. We also evaluated the effects of a proteasome inhibitor, MG132, and a histone deacetylase inhibitor, sodium butyrate, on NER efficiency using this assay. All these results suggest that the new assay is highly useful for the rapid and quantitative analysis of NER activity in various primary cells with limited growth activity and is applicable to a screening system for drugs affecting NER efficiency.     

Hierarchical subspace models for contingency tables

For the statistical analysis of multiway contingency tables, we propose modeling interaction terms in each maximal compact component of a hierarchical model. By this approach we can search for parsimonious models with smaller degrees of freedom than the usual hierarchical model, while preserving the localization property of the inference in the hierarchical model. This approach also enables us to evaluate the localization property of a given log-affine model. We discuss estimation and exact tests of the proposed model and illustrate the advantage of the proposed modeling with some data sets.     

Deep blue mixed-valent PtIIIPtIIIPtII complex [Pt3Br2(mu-pz)6] (pz=pyrazolate) showing valence-detrapping behavior in solution

The oxidation of the pyrazolate bridged cyclic PtII trimer, [Pt3(mu-pz)6] (1), in the presence of bromide ion gave a deep blue mixed-valent Pt(II,III,III) complex, [Pt3Br2(mu-pz)6] (2). The structural analysis of 2 disclosed that the complex has localized Pt--Pt bond. Our theoretical calculations revealed that the HOMO and LUMO of Pt3 (II,III,III) species mainly consists of (dsigma-dsigma) and (dsigma-dsigma)* orbitals, respectively, and the origin of deep blue color of the bromo complex, 2, arises from the (dsigma-dsigma)-->(dsigma-dsigma)* transition. Unique fluxional behavior was observed due to valence-detrapping of 2 in solution. The activation parameters of the valence-detrapping of 2 obtained by Eyring analyses were DeltaH(not equal)=37(2) kJ mol(-1) and DeltaS(not equal)=-67(7) J mol(-1) K(-1).     

Highly stereoselective asymmetric Pummerer reactions that incorporate intermolecular and intramolecular nonbonded S...O interactions

New chiral sulfoxides (R(S),S)-3, (S(S),S)-3, (R(S),S)-4, and (S(S),S)-4 and known chiral sulfoxides (R(S))-5, (R(S))-6, and (R(S))-7 were synthesized, and the stereochemistry of the new sulfoxides (R(S),S)-3 and (R(S),S)-4 was determined by X-ray crystallographic analysis. In their crystallographic structures, the intramolecular nonbonded S...O close contacts were recognized. Analyses of several sulfoxide complexes including rac-11 with N,N-dimethylacetamide (DMAC) or N-methyl-2-pyrrolidone (NMP) in a MeOH solution utilizing cold-spray ionization mass spectrometry provided, for the first time, direct information for intermolecular nonbonded S...O interactions between sulfoxides and amide (or lactam) in a solution. Highly diastereoselective and enantioselective Pummerer reactions based on the concept of intermolecular and intramolecular nonbonded S...O interactions were performed by treatment of several chiral sulfoxides (R(S), S)-3, (S(S), S)-3, (R(S), S)-4, (S(S), S)-4, (R(S))-5, (R(S))-6, and (R(S))-7 with acetic anhydride and trimethylsilyl triflate (TMSOTf) in DMAC, NMP, N,N-dimethylformamide, and N-formylpiperidine. Mechanistic studies on these facile stereoselective Pummerer reactions revealed the necessity for the amide/TMSOTf complex, such as 26 or 27, to be an efficient activation reagent for Ac(2)O and a trapping reagent for the released acetate ion, and that DMAC and NMP had a positive effect on this highly stereoselective chiral transfer reaction.     

Measurement of coherent terahertz radiation for time-domain spectroscopy and imaging

A high-power terahertz (THz) source for THz time-domain spectroscopy (THz-TDS) and THz imaging has been developed based on an S-band compact electron linac at the National Institute of Advanced Industrial Science and Technology (AIST). A THz pulse was generated as coherent synchrotron radiation (CSR) from an ultra-short electron bunch and expected to have peak power of kW-order with frequency range of 0.1–2 THz. The electro-optic (EO) sampling method with a ZnTe crystal for the THz pulse measurement has been prepared for THz-TDS system. The timing measurement between the THz pulse and a probe laser was carried out. A preliminary experiment of THz transmission imaging of an integrated circuit (IC) card has been successfully demonstrated using the THz CSR pulse and a W-band rf detector. The imaging result was experimentally compared with a result of X-ray imaging. It is confirmed that its intensity and stability are enough to perform for the THz applications.     

Charge–discharge performances of Li–S battery using NaI–NaBH4–LiI solid electrolyte

Journal of Solid State Electrochemistry - In this study, Li–S batteries were fabricated using 9(15NaI∙NaBH4)∙LiI as the solid electrolyte, and their charge–discharge...