Generalized Minkowski formulas for closed hypersuperfaces in Riemann space

Summary This paper generalizedMinkowski formulas for a closed orientable hypersurface in aRiemann space with constant curvature which have been introduced byC. C. Hsiung, and studies on some properties of the hypersurface whose the v-th mean curvature is constant, on making use of the generalized formulas. To Enrico Bompiani on his scientific Jubilee     

TOF-SIMS structural characterization of self-assembly monolayer of cytochrome b5 onto gold substrate

Orientation and three-dimensional structure of immobilized proteins on bio-devices are very important to assure their high performance. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is able to analyze upper surface of one layer of molecules. Orientation of immobilized proteins can be evaluated based on determination of a partial structure, representing ensemble of amino acids, on the surface part. In this study, a monolayer of cytochrome b5 was reconstituted onto gold substrate and investigated by surface plasmon resonance (SPR). After freeze-drying, the resulted protein self-assembly was evaluated using TOF-SIMS with the bismuth cluster ion source, and then TOF-SIMS spectra were analyzed to select peaks specific to cytochrome b5 and identify their chemical formula and ensembles of amino acids. The results from TOF-SIMS spectra analysis were compared to the amino acid sequence of the modified cytochrome b5 and three-dimensional structure of cytochrome b5 registered in the protein data bank. Finally, fragment-ion-generating parts of the immobilized-cytochrome b5 are determined based on the suggested residues and three-dimensional structure. These results suggest the actual structure and confirm the expected orientation of immobilized protein.     

TOF-SIMS analysis of magnetic materials in chum salmon head

A piece of tissue extracted from a chum salmon Oncorhynchus keta head was measured with time-of-flight secondary ion mass spectrometry (TOF-SIMS) in order to evaluate the distribution and composition of magnetic materials in the tissue, which may concern with geomagnetic navigation of long-distance migrating salmon. Several depositions of iron compounds were detected in the tissue by TOF-SIMS analysis. Comparing with total ion images providing a topological tissue structure, specific distribution of iron ion in the tissue was clearly shown. Higher magnification TOF-SIMS analysis revealed the existence of the aggregations of iron particles. Iron oxide clusters comprising many submicron particles were also detected in the tissue using scanning electron microscopy and X-ray analysis, suggesting the common existence of submicron-scale iron oxides in salmon heads. These results suggest that TOF-SIMS analysis is a valid method to clarify detailed structures and chemical properties of candidate magnetoreceptors in fish heads.     

Certified reference material for the determination of perfluorooctane sulfonate in acrylonitrile-butadiene-styrene resin (NMIJ CRM 8155-a)

A certified reference material (CRM) for the determination of perfluorooctane sulfonate (PFOS) in acrylonitrile-butadiene-styrene (ABS) resin (NMIJ CRM 8155-a) has been issued by the National Metrology Institute of Japan (NMIJ). The bulk material was prepared by mixing commercial ABS resin powder and potassium PFOS and cut into square plates (20 × 20 mm, 2 mm thick) as the CRM. Analytical processes combined with isotope-dilution mass spectrometry and liquid chromatography/mass spectrometry were optimised and applied for characterisation. One of the approaches adopted by NMIJ for certification is that results from two or more primary methods of measurement should be used; thus, two optimised isotope-dilution mass spectrometric methods (Methods 1 and 2 with reprecipitation and with reprecipitation/solid phase extraction, respectively, were validated mutually and employed) were used to determine the certified value. Homogeneity and stability of the square plates were evaluated and their uncertainty contributions (as relative standard uncertainties) were 1.43% for inhomogeneity and 6.96% for approximately two years’ instability. The certified mass fraction of linear PFOS (heptadecafluoro-1-octanesulfonic acid) in the CRM with expanded uncertainty (coverage factor k = 2, approximately 95% confidence interval) was (33.1 ± 5.0) mg kg^?1 as free acid of PFOS.     

Ligand-free Sonogashira coupling reactions with heterogeneous Pd/C as the catalyst

A variety of aryl iodides were coupled with aromatic and aliphatic terminal alkynes to give the corresponding 1,2-disubstituted aromatic alkynes in good yields by using only 0.4 mol % of the heterogeneous 10 % Pd/C as the catalyst without a ligand, copper salt, or amine in an aqueous medium.     

Marine diterpenoids with a briarane skeleton from the Okinawan soft coral Pachyclavularia violacea

Five new briarane-type diterpenoids, pachyclavulides E (5), F (6), G (7), H (8) and I (9), were isolated from the Okinawan soft coral Pachyclavularia violacea. The structures of these compounds were elucidated based on the results of spectroscopic analysis. Compound 5 showed a weak growth-inhibitory activity in vitro toward cancer cells.     

Biobased poly(2,5‐furandimethylene succinate‐co‐butylene succinate) crosslinked by reversible Diels–Alder reaction

We synthesized biobased poly(2,5‐furandimethylene succinate‐co‐butylene succinate) [P(FS‐co‐BS)] copolymers by polycondensation of 2,5‐bis(hydroxymethyl)furan, 1,4‐butanediol, and succinic acid. These copolymers could be crosslinked to form network polymers by means of a reversible Diels–Alder reaction with bis‐maleimide. The thermal properties, mechanical properties, and healing abilities of the P(FS‐co‐BS)s and the network polymers were investigated. The mechanical properties of the network polymers depended on the comonomer composition of the P(FS‐co‐BS)s and the maleimide/furan ratio in the network polymers. Some of the copolymers exhibited healing ability at room temperature, and their healing efficiency was enhanced by solvent or heat. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 216–222