Construction of conservative test for change-point problem in two-dimensional random fields

This paper is concerned with a change-point problem in random fields. Tests for detecting a change-structure in a two-way table are constructed. Solutions to this problem require calculations of multiple integrals, but the calculations become difficult as the table gets large. To overcome this difficulty, the tube method is developed in differential geometry. It is shown by simulations that the proposed method is superior to other available methods.     

Antioxidant and photo-antioxidant abilities of catechins

Catechins are studied vigorously, in particular, concerning the antioxidant ability as polyphenol, which is generally considered responsible for photo-antioxidant natures of catechins. In this study, the antioxidant and photo-antioxidant abilities of (+)-catechin, (−)-epicatechin, and epigallocatechin have been investigated kinetically and discussed in detail. As a result, this study clarifies that a strong antioxidant is not always a good photo-antioxidant as well as that catechins show a high antioxidant ability in an initial oxidation process and acquire a photo-antioxidant ability with the progress of photo-oxidation. In particular, (+)-catechin and (−)-epicatechin convert into quercetin to show a remarkable photo-antioxidant ability almost comparable to quercetin. In this case, (−)-epicatechin has a higher photo-antioxidant ability than (+)-catechin, although they differ only in the configurations. These facts are explained by the direct conversion of the catechins into quercetin.     

The search for cosmic strangelets with the supersonic concorde and with JACEE's circumpolar balloon flight in Antarctica

The search for cosmic strangelet nuclei was carried out by two experiments with emulsion chambers. A balloon-borne JACEE emulsion chamber was flown at 3.5 g/cm² for 200 h in Antarctica (JACEE-10 experiment) and the Concorde flights were made by ECHOS at an atmospheric depth of 110 g/cm² between Paris and New York. No nuclei withZ⩾30 survived after traversing 60–120 g/cm² of the detector materials in the JACEE instruments. No evidence for a long mean free path were found in the zenith angle distribution forZ/β⩾26 nuclei. The exposure factor used by the JACEE was 72 m²hsr. The intensity upperbounds,I⩽(2.2–9.7)×10⁻²/m²h sr, were obtained for strangelets having an atmospheric attenuation length of 220−50 g/cm², which corresponds to the case for mass numberA=100–10000 andZ/β > 13. Concorde experiments (ECHOS) used both a thin and a thick emulsion chamber. The total exposure was 209 m² h sr and no candidates with chargeZ⩾30 were found. The largest track hadZ/β=28.6±1.29 withβ ∼ 1. Nuclei observed with charge 13⩽Z⩽30 were consistent with the survival intensity of ordinary nuclei. The flux bounds from the ECHOS experiments were I⩽(2.1–5.0) x 10⁻²/m²h for strangelets with mass number 100⩽A⩽1000.     

Urinary metabolic profile of phenylketonuria in patients receiving total parenteral nutrition and medication

Nutrition and drugs are main environmental factors that affect metabolism. We performed metabolomics of urine from an 8‐year‐old patient (case 1) with epilepsy and an 11‐year‐old patient (case 2) with malignant lymphoma who was being treated with methotrexate. Both patients were receiving total parenteral nutrition (TPN). We used our diagnostic procedure consisting of urease pretreatment, partial adoption of stable isotope dilution, gas chromatography/mass spectrometry (GC/MS) measurement and target analysis for 200 analytes including organic acids and amino acids. Surprisingly, their metabolic profiles were identical to that of phenylketonuria. The neopterin level was markedly above normal in case 1, and both neopterin and biopterin were significantly above normal in case 2. Mutation analysis of genomic DNA from case 1 showed neither homozygosity nor heterozygosity for phenylalanine hydroxylase deficiency. The metabolic profiles of both cases were normal when they were not receiving TPN. TPN is presently prohibited for individuals who have inherited disorders that affect amino acid metabolism. Although the Phe content of the TPN was not the sole cause of the PKU profile, its effect, combined with other factors, e.g. specific medication or possibly underlying diseases, led to this metabolic abnormality. The present study suggests that GC/MS‐based metabolomics by target analysis could be important for assuring the safety of the treatments for patients receiving both TPN and methotrexate. Metabolomic profiling, both before and during TPN, is useful for determining the optimal nutritional formula not only for neonates, but also for young children who are known heterozygotes for metabolic disorders or whose status is unknown. Copyright © 2009 John Wiley & Sons, Ltd.     

A combined experimental and theoretical investigation on the oxygenation of organic sulfides by oxo(salen)chromium(V) ion

The mechanism of oxygenation of organic sulfide by oxo(salen)chromium(V) complexes has been studied experimentally and by the density functional theory (DFT) method. Spectral studies show DMSO ligands bind with the Cr center of oxidant and the adduct formed was responsible for the oxygenation reaction. The reaction was first order with respect to oxidant and substrate. Hammett plot shows the formation of positive charge over sulfur atom and the development of negative charge over the oxidant in the transition state (TS). For the substrate ρ values are in the range from ?1.5 to ?1.8. The geometry has been correctly predicted by the B3LYP function, and it gives better results for spin states, harmonic frequencies, and thermodynamic energies for the system. DFT results indicate the existence of oxo(salen)chromium(V) and Cr(III)–salen at doublet and quartet as ground state, respectively. Binding of donor ligand weakens the Cr? O bond. TS structures show an increase in the negative charge and spin density over Cr atom indicating the involvement of spin inversion and radical character. The low activation energy and high free energy change are responsible for the enhancement of the reaction rate and product yield in the presence of DMSO donor ligand, while the rebound mechanism and the direction of substrate approach perpendicular to the salen plane are responsible for their higher selectivity. From this combined study, a mechanism involving consecutive two‐electron transfer from the oxo(salen)chromium(V) ion to the electron‐rich sulfur atom is proposed. Copyright © 2008 John Wiley & Sons, Ltd.     

Facile synthesis of 2-unsubstituted benzofuran-3-carboxylates using diazo(trimethylsilyl)methylmagnesium bromide

Diazo(trimethylsilyl)methylmagnesium bromide reacted with (o-methoxyphenyl)(oxo)acetates to readily afford 2-unsubstituted benzofuran-3-carboxylates via oxonium ylides formed from the initially generated alkylidenecarbene intermediates.     

Mean wind in convective turbulence of mercury

The large-scale circulation, often called "wind," in the confined thermal turbulence of mercury is studied experimentally. The instantaneous velocity profile at 128 points is directly measured using ultrasonic velocimetry. The periodic velocity oscillation is observed in the case of the aspect-ratio Gamma = 1,2 but not in Gamma = 0.5. Its peak frequency is scaled by f(c) proportional Ra(gamma(c)), where Ra is the Rayleigh number and gamma(c) = 0.43,0.45 for Gamma = 1,2. f(c) is close to the wind circulation frequency f(p), and has the same order of transit time from the bottom to the top of the convection cell. A single roll circulation is expected in Gamma = 1; however, axisymmetric toroidal rings may exist near the upper and lower plate for Gamma = 0.5, which are stable up to Ra = 7 x 10 (10).