Anomalous bumpy structures in the capture cross sections of antiprotons by helium

We investigate the state-specified capture process of antiprotons by helium. Freezing one of the two electrons, we reduce this four-body rearrangement problem into a three-body problem. The capture cross sections are calculated by solving the Chew-Goldberger-type integral equation. Differing from the capture of antiprotons by hydrogen atoms, the bumpy structures are revealed in the total angular momentum dependent capture cross sections. Further analysis shows that the bumps arise from the partial channel closing due to the removal of the energy degeneracy in the antiprotonic helium.     

Photocontrol of spatial orientation and DNA cleavage activity of copper(II)-bound dipeptides linked by an azobenzene derivative

Copper(II) ion-bound CysGly dipeptides linked by an azobenzene derivative were photoisomerized between the trans and cis forms. The two copper(II) ion centers were positioned close to each other in the cis form, whereas they were far away from each other in the trans form. The copper complex in the cis form exhibited DNA cleavage activity, whereas the activity in the trans form was negligible. The DNA cleavage activity of the cis form is attributed to the cooperation of the closely located copper(II) centers. The present results show the photocontrol of the cooperation of metal ions for DNA cleavage.     

Preparation of superacid of ruthenium-sulfated zirconia for reaction of butane to isobutane

A highly active superacid of 2–4 wt.% Ru-sulfated ZrO₂ for the isomerization of butane to isobutane was obtained by exposing RuO_x/ZrO₂ to 1 N H₂SO₄ followed by calcining in air at 550°C. The RuO_x/ZrO₂ was prepared by impregnating zirconium hydroxide with a solution of RuCl₃ followed by drying at 300°C. The catalyst was much more active than the superacid of sulfated zirconia, the temperature difference to show the same conversion between both catalysts being more than 145°C.     

Polarized neutron reflectometer SUIREN at JRR-3

Recent status of the neutron reflectometer SUIREN is presented. Since its startup in 2006, SUIREN has been the only neutron reflectometer in Japan for magnetic samples with high magnetic field sample environment, and used for investigations of magnetic films, solid-liquid interfaces and other solid thin films. SUIREN provides monochromatic neutron beam of 3.93 Å for vertically placed sample surface. Polarized beam is also available together with a 1 T electromagnet for sample. Beam intensity at the sample position in the unpolarized mode is for beam collimation of Δθ=0.08. Reflectivity can be explored down to 10^-6.     

Peripherally Monomial-Preserving Maps between Uniform Algebras

Let and be uniform algebras and p(z,w) = z^mwⁿ a twovariable monomial. We characterize maps T from certain subsets of into such that holds for all f and g in the domain of T; peripherally monomial-preserving maps. Furthermore and are proved to be isometrical isomorphic as Banach algebras. If the greatest common divisor of m and n is 1, then T is extended to an isometrical linear isomorphism; a weighted composition operator. An example of peripherally monomial-preserving surjections between uniform algebras which is not linear, nor multiplicative, nor injective is given when the greatest common divisor is strictly greater than 1. The first, third and fourth authors were partly supported by the Grantsin-Aid for Scientific Research, The Ministry of Education, Science, Sports and Culture, Japan.     

Method validation by interlaboratory studies of improved hydrophilic oxygen radical absorbance capacity methods for the determination of antioxidant capacities of antioxidant solutions and food extracts

Hydrophilic oxygen radical absorbance capacity (H-ORAC) is a method for evaluating antioxidant capacities of solutions of hydrophilic compounds. In this study, we improved the original method for H-ORAC determination, and evaluated the precision of the two improved methods (methods A and B) by interlaboratory studies using 5 antioxidant solutions and 5 food extracts as test samples. An interlaboratory study of method A, in accordance with the harmonized protocol, demonstrated satisfactory performance (intermediate precision relative standard deviations (RSD(int)) ranging from 4.6 to 18.8%; the reproducibility relative standard deviations (RSD(R)) ranging from 7.0 to 21.1%, and the HorRat values ranging from 0.40 to 1.93). However, methodological problems remained, and a further improved method, method B, was thus developed. An interlaboratory study of method B by 5 participating laboratories showed better intermediate precision and reproducibility (RSD(int) and RSD(R) ranging from 1.8 to 9.4%, and from 4.4 to 13.8%, respectively), and all HorRat values for the test samples were less than 1.3, suggesting good performance for the H-ORAC measurement.     

Catalysis of Ruthenium-Metal Oxides Mechanically Mixed with Sulfated Zirconia for Reaction of Butane to Isobutane

A highly active catalyst for the skeletal isomerization of butane to isobutane was obtained by mechanically mixing SO₄/ZrO₂ and Ru/SnO₂; Ru/SO₂ was prepared by impregnating tin hydroxide with a solution of RuCl₃ followed by calcining at 450°C (0.5 wt.% Ru). The catalyst was much more active than Ru-SO₄/ZrO₂ prepared by co-impregnation of zirconia with the Ru and sulfate materials the temperature difference to show the same conversion between both catalysts being 57°C. The effect of mixing of Ru was observed with other metal oxides as supports, Fe₂O₃, Al₂O₃, ZrO₂, TiO₂, and SiO₂; the calcination temperature of the Ru-impregnated hydroxides was 250, 300, and 400°C for the latter three, respectively.     

Specific and chemoselective multi-alpha-arylation reaction of benzoylformic acid with or without decarbonylation in P(2)O(5)-MsOH and related acidic media

In P(2)O(5)-MsOH, or related acidic media, benzoylformic acid (1) undergoes three types of di- or mono-alpha-arylation reactions with or without decarbonylation ((1) decarbonylative alpha, alpha-diarylation, yielding triarylmethanols 6, (2) decarbonylative alpha-monoarylation, giving benzophenone derivatives 7, and (3) alpha,alpha-diarylation without decarbonylation, affording diarylated carboxylic acids 5) and one simple decarbonylation, without arylation, to form benzoic acid (8), instead of the conventional Friedel-Crafts acylation type reaction. The product ratios are governed by the capability of the acidic medium to form mixed anhydrides with carboxylic acids and the ability of the arenes to accept electrophiles.