A generalization of Coxeter groups,root systems,and Matsumoto’s theorem

The root systems appearing in the theory of Lie superalgebras and Nichols algebras admit a large symmetry extending properly the one coming from the Weyl group. Based on this observation we set up a general framework in which the symmetry object is a groupoid. We prove that in our context the groupoid is generated by simple reflections and Coxeter relations. In a broad sense this answers a question of Serganova. Our weak version of the exchange condition allows us to prove Matsumoto’s theorem. Therefore the word problem is solved for the groupoid.     

Assay of Angiotensin I-converting Enzyme-inhibiting Activity Based on the Detection of 3-Hydroxybutyrate with Water-soluble Tetrazolium Salt.

A newly synthesized substrate, 3-hydroxybutyrylglycyl-glycyl-glycine (3HB-GGG), was applied to the assay of ACE-inhibiting activity to overcome the smaller selectivity and sensitivity of the conventional method. In this study, an ACE-inhibiting assay was improved by the use of a water-soluble tetrazolium salt, 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate sodium salt (WST-1), for the detection of 3-hydroxybutyrate, derived from 3HB-GGG. The optimized conditions were as follows: 0.333 mM NAD(+), 0.333 mM WST-1, 0.1 mM EDTA, 0.633 U ml(-1) diaphorase, and 0.700 U ml(-1) 3-hydroxybutyrate dehydrogenase. The developed assay was efficiently applicable to evaluate the ACE-inhibiting activity of practical ACE inhibitors.     

Determination of benzophenones in river-water samples using drop-based liquid phase microextraction coupled with gas chromatography/mass spectrometry.

In this study, a fast, simple and highly sensitive method that employs liquid phase microextraction (LPME)-GC/MS was developed to analyze trace benzophenones (BPs) in river-water samples. The tip of a 10-microl microsyringe filled with toluene (3 microl) was inserted into 2 ml of a river-water sample, and fixed at 5 mm below the water surface of the sample. A toluene droplet was made on the tip of the syringe, and extraction was conducted while agitating at 500 rpm for 15 min. After extraction, 2.0 microl of the extract was put into the syringe again, and directly introduced to GC/MS. The limits of detection (S/N = 3) and quantification (S/N >10) of BPs were 10 and 50 pg ml(-1), respectively. The results of a recovery test ranged over 93.3 - 101.1% (RSD, less than 10%; n = 6). The results of BPs determinations in the river-water samples showed that BPs (ND - 68.9 pg ml(-1)) were detected.     

Transferred hyperfine field in the pseudo-binary compound Y(Fe,Mn)2

The NMR of⁸⁹Y in Y(Fe_1−xMn_x)₂ has been observed. Two kinds of Mn moments were estimated by analyzing the⁸⁹Y hyperfine field: (1) the low spin state with about 0.6 μ_B in antiparallel to Fe moment and (2) the high spin state with about 2.8 μ_B in parallel to Fe moment. The magnetizations estimated from NMR results are in good agreement with those of magnetization measurements.     

Organic thin films based on a dicyanovinyl-quaterthiophene: Influence of electrode configuration on third-order nonlinear optical properties measured by electroabsorption spectroscopy

Electroabsorption (EA) studies at room temperature on organic thin films based on a dicyanovinyl-quaterthiophene 4T-V(CN)₂ are reported. An electric field modulation is applied to the samples for two different electrode geometries, i.e. sandwich and coplanar versus the organic layer. Changes in optical absorption coefficient of 4T-V(CN)₂ based thin films are measured and analyzed to determine the character of the optical transition in the visible range (400-800 nm). Depending on the experimental electrode configuration, magnitude of electroabsorption responses are different, possibly due to different distribution of the externally applied electric field. The results indicate a higher resolution of EA response for the sandwich electrode configuration and confirm the charge transfer exciton character of 4T-V(CN)₂ in contrast to the unsubstituted quaterthiophene 4T. Finally, a third-order nonlinear susceptibility χ⁽³⁾ (−ω; ω, 0, 0) of 16 × 10⁻¹² e.s.u. is obtained.     

Controlling anisotropy of GaSb(As)/GaAs quantum dots by self-assembled molecular beam epitaxy

A systematic study was performed to control the geometrical anisotropy of GaSb(As)/GaAs quantum dot structures formed by the Stranski–Krastanov growth mode of molecular beam epitaxy. In particular, effects of both the Sb₄ beam flux and the As₄ background pressure on the geometrical anisotropy were clarified and elongated QDs with lateral aspect ratio greater than 3 were successfully formed. Under a low As₄ background pressure, As₄ is found to act as surfactant to influence the adatom diffusion and change the density of QDs. By contrast, under high As₄ background pressure, the intermixing of As and Sb takes place and reduces strains induced by the lattice mismatch.     

Thermal decomposition of propane in shock waves

The thermal decomposition of propane was studied behind reflected shock waves over the temperature range 1100–1450 K and the pressure range 1.5–2.6 atm, by both monitoring the time variations of absorption at 3.39 μm and analyzing the concentrations of the reacted gas mixtures. The rate constants of the elementary reactions were discussed from the results. The rate constant expressions, k₁ = 1.1 × 10¹⁶ exp (?84 kcal/RT) s^?1 and k₄ = 9.3 × 10¹³ exp(?8 kcal/RT) cm³ mol^?1 s^?1, of reactions C₃H₈ → CH₃ + C₂H₅ and C₃H₈ + H → n-C₃H₇ + H₂ were evaluated, respectively.     

Synthesis and properties of the [2.2]paracyclophane‐containing conjugated polymer with benzothiadiazole as an electron acceptor

A novel donor–acceptor type conjugated polymer based on PPE with [2.2]paracyclophane and benzothiadiazole units in the main chain was synthesized by the Sonogashira coupling reaction. The obtained polymer was quite soluble in common organic solvents, and the transparent and uniform thin film of the polymer was obtained easily by casting or spin‐coating from a toluene solution. The polymer showed an extension of π‐delocalization via the through‐space with π‐π stacking according to the UV–visible (UV–vis) absorption spectra in comparison with that of the model compound. The polymer exhibited orange photoluminescence in solution (fluorescence quantum efficiency = 0.13) and in the solid state. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5891–5899, 2004