Complete NMR analysis of oxytocin in phosphate buffer

Complete NMR analysis of oxytocin (OXT) in phosphate buffer was elucidated by one‐dimensional (1D)‐ and two‐dimensional (2D)‐NMR techniques, which involve the assignment of peptide amide NH protons and carbamoyl NH₂ protons. The ¹H? ¹⁵N correlation of seven amide NH protons and three carbamoyl NH₂ protons were also shown by HSQC NMR of OXT without ¹⁵N enrichment. Copyright © 2009 John Wiley & Sons, Ltd.     

A local structure theorem on 5‐connected graphs

An edge of a 5‐connected graph is said to be contractible if the contraction of the edge results in a 5‐connected graph. Let x be a vertex of a 5‐connected graph. We prove that if there are no contractible edges whose distance from x is two or less, then either there are two triangles with x in common each of which has a distinct degree five vertex other than x, or there is a specified structure called a K₄^?‐configuration with center x. As a corollary, we show that if a 5‐connected graph on n vertices has no contractible edges, then it has 2n/5 vertices of degree 5. © 2008 Wiley Periodicals, Inc. J Graph Theory 60: 99–129, 2009     

Furan derivatives. Part 10. Synthesis of cyclohepta[cd]benzofuran

Cyclohepta[cd]benzofuran 2 was synthesized by heating (5-oxo-5H-benzocyclohepten-4-yloxy)acetic acid 16 with sodium acetate in acetic anhydride or by photocyclization of 16 in acetonitrile. Several reactions of cyclohepta[cd]benzofuran 2 were examined. Protonation of 2 with trifluoroacetic acid occurred at the 2-position to give a tropylium ion 17 . Catalytic hydrogenation of 2 with palladium on charcoal proceeded smoothly to give tetrahydrocyclohepta[cd]benzofuran 18 . The Diels-Alder reaction of 2 with tetracyano-ethylene produced an adduct 19 . Formylation of 2 with phosphorus oxychloride and dimethylformamide occurred easily at the 2-position to afford compound 20 . Cyclohepta[cd]benzofuran 2 has both properties of heptafulvene and benzofuran.     

Observation of THz coherent transition radiation from single-bunch beam at KURRI-LINAC as an intense pulsed light source

A single-bunch beam has been generated using a developed high-speed avalanche-type pulser in KURRI-LINAC in order to lift restrictions of the spectral resolution in the spectroscopic study and the delay time in the time-resolved measurement. Both of the rise and fall times of the developed pulser are 110 ps. The observation of CTR has confirmed the single-bunch beam. The degree of impurity of single bunch has been estimated to be 1.5% by the analysis of the interferogram.     

Furan derivatives. Part 12 . Synthesis of 2,5-dioxacyclohepta[jkl]-as-indacenes

A variety of 2,5-dioxacyclohepta[jkl]-as-indacenes 5, 7–14 were synthesized as a new heterocycle by the treatment of diethyl (5,9-dioxobenzocyclohepten-1,4-diyloxy)diacetates 4a-e with potassium hydroxide or sodium hydride in dioxane. The mechanism of furan-ring formation from 4a-e was discussed.     

Transient DSC,a Novel and Rapid Method for Assessing Pharmaceutical Powder Compacts

The previously described method involving the use of transient DSC was applied to pharmaceutical powder compacts and to ceramic powder compacts. The samples were prepared by compressing powders of pentaerythritol tetraacetate and two kinds of alumina powder (differing in particle size distribution) up to a pressure of 20 MPa by using a jig. For pentaerythritol tetraacetate, a linear relationship was obtained between the parameter obtained by DSC and the compaction pressure. This revised version was published online in August 2006 with corrections to the Cover Date.     

An application of fragment interaction analysis based on local MP2

We have developed a method named ‘fragment interaction analysis based on local MP2’ (abbreviated as FILM). This method enables us to decompose the interaction energy associated with dispersion interactions into contributions of localized occupied orbitals. In this study, the basis set dependence of the results derived from FILM was examined. The results suggested that the individual ratio of pair correlation energies of selected orbital pairs to the total dispersion interaction was almost independent of the basis set size. As an illustrative example, detailed analysis was performed on the human immunodeficiency virus type 1 protease complexed with lopinavir molecule.     

Oxygen-assisted shape control in polyol synthesis of silver nanocrystals

We have found that the shape of silver nanocrystals is conveniently controlled by injection of oxygen gas during the polyol reduction of silver ions. The presence of oxygen effectively promotes the oxidative etching of multiple twined particles. Adjusting the flow rate of the oxygen gas yields uniformly-sized silver nanocubes, right bipyramids, nanowires, and spherical nanoparticles depending on the injection rate of the oxygen gas. Electron diffraction and high resolution TEM observations of the synthesized nanocrystals show our nanocrystals do consist of silver, not of silver oxide. SERS activities of the synthesized nanocrystals were also examined.