Three-flavor quark mass dependence of baryon spectra in holographic QCD

We introduce the strange quark mass to the Sakai–Sugimoto model of holographic QCD. We compute mass shifts in the spectra of three-flavor baryons at the leading order in perturbation in quark masses. Comparison with experimental data shows an agreement only qualitatively.     

Isolation and Ambident Reactivity of a Chlorogermylenoid

Treatment of 2,5‐di(3,5‐tert‐butylphenyl)‐1‐lithioferrocene with GeCl₂?dioxane afforded the corresponding chlorogermylenoid that exhibited an ambident reactivity in different solvents; it displayed a behavior characteristic for a dichlorogermylene anion in THF, while it exhibited the typical reactivity of a chlorogermylene in toluene. X‐Ray diffraction analysis of a single crystal of this chlorogermylenoid, obtained from recrystallization in THF, revealed a separated‐ion‐pair structure in the solid state.     

Molecular Propellers that Consist of Dehydrobenzo[14]annulene Blades

A new class of propel‐ ler‐shaped compound ( 4 ), which consisted of dehydrobenzo[14]annulene ([14]DBA) blades, as well as its naphtho homologues ( 5 and 6 ), have been prepared. Although NMR studies of compound 4 did not provide useful information regarding its conformation in solution, DFT calculations with different functionals and the 6‐31G* basis set all indicated that the D₃‐symmetric structure was energetically more favorable than the C₂ conformer. From X‐ray crystallographic analysis, it appeared that compound 4 adopted a propeller‐shaped‐, approximately D₃‐symmetric structure in the solid state, in which the [14]DBA blades were twisted substantially owing to steric repulsion between the neighboring benzene rings. On the contrary, in the case of compound 6 , although the DFT calculations with the B3LYP functional predicted that the D₃‐symmetric conformation was more stable, calculations with the M05 and M05‐2X functionals indicated that the C₂ conformer was more favorable because of π–π interactions between the naphthalene units of a pair of neighboring blades. Indeed, X‐ray analysis of compound 6 showed that it adopted an approximately C₂‐symmetric conformation. Moreover, on the basis of variable‐temperature ¹H NMR measurements, we found that compound 6 adopted a C₂ conformation and the barrier for interconversion between the C₂–C₂ conformers was estimated to be 16.2 kcal mol^?1; however, no indication of the presence of the D₃ isomer was obtained. The relatively small energy barriers to interconversion, despite the large overlapping of neighboring blades, was ascribed to the flexibility of the acetylene linkages, which could be deformed substantially in the transition state of the ring‐flip.     

Total Syntheses of (−)-Strictosidine and Related Indole Alkaloid Glycosides

A collective synthesis of glycosylated monoterpenoid indole alkaloids is reported. A highly diastereoselective Pictet–Spengler reaction with α-cyanotryptamine and secologanin tetraacetate as substrates, followed by a reductive decyanation reaction, was developed for the synthesis of (−)-strictosidine, which is an important intermediate in biosynthesis. This two-step chemical method was established as an alternative to the biosynthetically employed strictosidine synthase. Furthermore, after carrying out chemical and computational studies, a transition state for induction of diastereoselectivity in our newly discovered Pictet–Spengler reaction is proposed. Having achieved the first enantioselective total synthesis of (−)-strictosidine in just 10 steps, subsequent bioinspired transformations resulted in the concise total syntheses of (−)-strictosamide, (−)-neonaucleoside A, (−)-cymoside, and (−)-3α-dihydrocadambine.     

Mechanics and correlations of flow phenomena in intersecting ducts

Three kinds of experiments are conducted to determine flow characteristics inside two intersecting square ducts: flow visualization by means of the dye injection, hydrogen bubble and string methods, velocity measurement using the laser Doppler anemometry, and pressure measurement using a piezometer. Angle of intersection and Reynolds number are varied. Four distinct flow regimes are disclosed: entrance, initial centrifugal, intersecting and final centrifugal regions. The geometrical dividing line in the intersection zone of the two ducts forms a flow divider separating the flow network into two independent, symmetrical flow units. Each flow unit constitutes a curved passage with a radius of curvature whose magnitude varies with the angle of intersection. Hence, the secondary effects prevail in each unit, resulting in complete flow mixing. The mechanisms disclosed by the flow visualization and LDA methods are supported by the quantitative results from the piezometer measurements. The string method discloses an important evidence that the intersecting zone promotes turbulence. A location of the maximum energy grade and minimum hydraulic grade is disclosed on the flow divider where the surrounding streamlines congregate and disperse.     

The measurement of various molecules of pyrolysis gas of coal by using VUV-SPI-TOFMS

We developed and tested a system that combines a vacuum ultraviolet single photon ionization time-of-flight mass spectrometer (VUV-SPI-TOFMS) with a Fourier transform-infrared (FT-IR) spectrometer and used it for the simultaneous detection of the various compounds generated during the pyrolysis of coal. We characterized the performance of the system, including its limits of detection and time resolution. We also determined the various compounds that could be detected using the system. The instrument exhibited a laboratory-determined detection limit that was in the parts per billion volume (ppbv) range and a detection time of 10 s for most of the aromatic compounds generated during the pyrolysis process. In addition, using this system, it was possible to determine the correlation between the pyrolysis temperature and the various compounds generated from different types of coals during the pyrolysis process.     

Surface modification of ethylene‐co‐tetrafluoroethylene films by remote plasmas

The surface modifications of ethylene‐co‐tetrafluoroethylene (ETFE) surfaces by six plasmas (direct H₂, Ar, and O₂ plasmas and remote H₂, Ar, and O₂ plasmas) were investigated with two questions in mind: (1) what plasma could effectively modify ETFE surfaces and (2) which of the CF₂? CF₂ and CH₂? CH₂ components in ETFE was selectively modified? The plasma exposure led to a weight loss from the ETFE surfaces and changes in the chemical composition on ETFE surfaces. The weight‐loss rate showed a strong dependence on what plasma was used for the modification. The remote H₂ plasma led to the lowest rate of weight loss in the six plasma exposures, and the direct O₂ plasma led to the highest rate of weight loss. During exposure to the plasmas, defluorination occurred, and two new C_1s components [? CH₂? CHF? CH₂? and ? CH₂? CH(O? R)? CF_x? , and ? CH₂? CHF? CF₂? , ? CH₂? C(O)? CF_x? , and ? CF_x? C(O)? O? ] were formed on the modified ETFE surfaces. Defluorination was strongly influenced by what plasma was used for the modification. The remote H₂ and Ar plasmas showed high defluorinations of 55 and 51%, respectively. The remote O₂ plasma showed a low defluorination of only 25%. Conclusively, the remote H₂ and Ar plasma exposure effectively modified ETFE surfaces. With the exposure of these surfaces to the remote H₂ plasma, the CF₂? CF₂ component was predominantly modified, rather than the CH₂? CH₂ component. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2871–2882, 2002     

Application of Koszul complex to Wronski relations for $U(\frak{gl}_n)$

Explicit relations between two families of central elements in the universal enveloping algebra $U(\frak{gl}_n)$ of the general linear Lie algebra $\frak{gl}_n$ are presented. The two families of central elements in question are the ones expressed respectively by the determinants and the permanents: the former are known as the Capelli elements, and the latter are the central elements obtained by Nazarov. The proofs given are based on the exactness of the Koszul complex and the Euler-Poincaré principle.