PtBr2-catalyzed consecutive enyne metathesis-aromatization of 1-(1-methoxy-but-3-enyl)-2-(1-alkynyl)benzenes: dual role of the Pt catalyst

1,7-Enynes 1, connected through an aromatic ring and bearing a leaving methoxy group at the 4-position, underwent the PtBr(2)-catalyzed enyne metathesis followed by aromatization in one pot to afford vinyl naphthalenes 3 in good to acceptable yields. The cyclobutene intermediate 11a and another intermediate 2a were isolated, indicating that PtBr(2) acts as a dual role catalyst: (1) as a transition metal catalyst, it induces the enyne metathesis to produce 11a starting from 1a, and (2) as a Lewis acid catalyst, it facilitates elimination of MeOH from 2a to give the aromatized product 3a.     

Electron attachment and vibrational excitation in hydrogen iodide: calculations based on the nonlocal resonance model

High resolution laser spectroscopy has been applied to study the hyperfine structure of excited energy levels of Thulium I. As part of our aim to complete the fine and hyperfine structure of the Tm I spectra 51 transitions in the visible were measured and precise values for the magnetic dipole hyperfine structure constants A of 24 odd and 19 even levels were determined. In addition, a new energy level of even parity with J = 3/2 is found at 27 509.40 (5)cm^?1 using laser induced fluorescence spectroscopy.     

Analysis of the interaction between human plasma fibronectin and gelatin by affinity electrophoresis

The interaction between human plasma fibronectin and gelatin was analyzed by affinity electrophoresis, in which the fibronectin was subjected to electrophoresis in a 4% polyacrylamide gel in the presence and absence of gelatin, as an affinity ligand, and the fibronectin band was stained by an immunoblotting method. The apparent dissociation constants (Kd) of fibronectin for gelatin were calculated from affinity plots based on the original affinity equation at different pHs, urea concentrations, and temperatures. The fibronectin exhibited much lower affinity in the presence of urea. The Kds at 37 degrees C were 1.49 X 10(-7) M, 2.50 X 10(-6) M, and 3.58 X 10(-6) M with 2 M, 3 M, and 4 M urea, respectively. The van't Hoff plots of Kd values against absolute temperature (T) showed that the value of log Kd decreased in proportion to the increase in the value of 1/T within the range of 15-50 degrees C. The standard enthalpy, the standard free energy change at 37 degrees C, and the entropy change at 37 degrees C for association were calculated to be -124.7 kJ/mol, -33.23 kJ/mol, and -295.1 J/mol/deg, respectively. These results suggest that a hydrophilic interaction, such as hydrogen bond or van der Waals interaction, plays an important role in the binding of plasma fibronectin to gelatin.     

Measurement of hyperfine structure constants,g values and tensor polarizability of excited states of Sm I

Atomic-beam laser spectroscopy with fluorescence detection is applied to investigate the hyperfine structure (hfs), Stark and Zeeman effects of the electric dipole transitions of Sm i. The measurements are performed for the four transitions of 0 → 15650.55, 292.58 → 15650.55, 292.58 → 15567.32, and 1489.55 → 16890.59 cm^-1. The hfs constants of the upper and lower levels and the isotope shifts of the transitions are determined. The tensor polarizability of the 15650.55 cm^-1 level is found to be α₂ = -556.2 ± 11.8 kHz/(kV/cm)². Thanks to the accurate g values of the lower levels [Childs, W.J., Goodman, L.S.: Phys. Rev. A 6, 2011 (1972)], the g values of the upper levels are obtained from the observed Zeeman splittings. The values are found to be -0.115907(79), 2.22259(20) and 1.599968(51) for the 15650.55 cm^-1 .1, 15567.32 cm^-1 and 16890.59.cm^-1 levels, respectively.     

Optical sensor for carbon dioxide combining colorimetric change of a pH indicator and a reference luminescent dye

A new optical CO₂ sensor based on the luminescence intensity change of the europium(III) complex tris(thenoyltrifluoroacetonato) europium(III) dihydrate ([Eu(tta)₃]) caused by the absorption change of various pH indicators—thymol blue, phenol red, or cresol red—with CO₂ was developed and its CO₂ sensing properties were investigated. For all the CO₂ sensors using pH indicators the observed luminescence intensity from [Eu(tta)₃] at 613 nm increased with increasing CO₂ concentration. The linear calibration method based on the plot of (I₁₀₀–I₀)/(I–I₀) versus the inverse of CO₂ concentration was suggested, where I₀ and I₁₀₀ were luminescence intensities at 613 nm of the CO₂ sensor film in 100% nitrogen and 100% gaseous CO₂. In all cases the plots showed good linearity and the correlation factors of the plots, r², were 0.991 for thymol blue, 0.990 for phenol red, and 0.998 for cresol red. The slopes of the plots (A/B) for thymol blue, phenol red, and cresol red were 2.2, 5.2, and 9.0%, respectively. The response times of the CO₂ sensor film were 4.0 s for thymol blue, 4.4 s for phenol red, and 8.8 s for cresol red for switching from nitrogen to CO₂, and the recovery times of films were 36 s for thymol blue, 39.2 s for phenol red, and 56.6 s for cresol red for switching from CO₂ to nitrogen. The signal changes were fully reversible and hysteresis was not observed during the measurements. The highly sensitive CO₂ sensor was developed using thymol blue as an indicator for the CO₂-sensing probe.     

In Situ Processing of Nano Crystalline Oxide Particles/Polymer Hybrid

Nano sized crystalline particles/polymer hybrids were synthesized form designed metal-organic precursors. The newly developed method is composed of the synthesis of organic matrix by polymerization and the in situ nucleation and growth of crystalline oxide particles in the organic matrix below 100°C. The design of metal-organic precursor modified with polymerizable ligand and the selection of reaction conditions does influence the size and crystallinity of ceramic particles in organic matrix. The nano-sized magnetic particle/polymer hybrid exhibits the interesting feature of superparamagnetism and quantum size effect. The crystalline particles of BaTiO₃/, PbTiO₃/, and KNbO₃/polymer hybrids behave to be dielectric and show the typical electro-rheological behavior.     

Determination of 21-hydroxycorticosteroids in human urine by high-performance liquid chromatography with fluorescence detection

A simple and sensitive high-performance liquid chromatographic method with fluorescence detection for the determination of nineteen 21-hydroxycorticosteroids is described. The corticosteroids are oxidized by cupric acetate to form the corresponding glyoxal derivatives. The derivatives are converted into fluorescent quinoxalines by reaction with 1,2-diamino-4,5-methylenedioxybenzene, a fluorogenic reagent for alpha-dicarbonyl compounds. The quinoxalines are separated within 70 min on a reversed-phase column (TSK gel ODS-120T) by stepwise elution with mixtures of methanol, acetonitrile, and 1.0 M ammonium acetate. The detection limits are 0.14-29.4 pmol at a signal-to-noise ratio of 3 in a 50-microliter injection volume. This sensitivity permits precise determination of hydrocortisone, cortisone, corticosterone, and their tetrahydro derivatives in 500 microliters of normal human urine.     

Development of rectangular column structured titanium oxide photocatalysts anchored on silica sheets by a wet process

Commercially available powdered photocatalysts such as P-25 are known to show high photocatalytic performance. However, in practical use, their anchoring onto a substrate without any binders is still very difficult. The purpose of this study is to design and develop high-performance photocatalysts that can be anchored onto a substrate, and to this end we have prepared a titanium oxide photocatalyst using a wet process. The results of this study led to the successful development of rectangular column structured titanium oxide crystals which could be anchored onto silica sheets. The rectangular columnar crystal was 100- 500 nm wide and 1000- 5000 nm long. Moreover, investigations on the complete oxidation reaction of acetaldehyde into CO₂ and H₂O showed a high performance equivalent to that of the most efficient marketed powdered photocatalysts.     

Stimulatory effect of red light on starch accumulation in a marine green alga,chlamydomonas sp. strain MGA161

A marine green alga,Chlamydomonas sp. strain MGA161 was cultivated under illumination of red and white lights. The growth rate under red light illumination was almost the same as that in the basic conditions under white light illumination, but red light-grown cells accumulated almost twice as much starch as white light-grown cells. Although there was a slight decrease in carbonic anhydrase activity, red light-illuminated cells had almost 2.3 times the fructose-l,6-diphos-phatase activity of white light-illuminated cells. Red light might stimulate starch accumulation by increasing the amounts of enzymes related to carbon fixation through the phytochrome system. Cells grown under red light degraded 1.6 times as much starch and produced 1.7 times as much hydrogen and 1.6 times as much ethanol compared with cells grown under white light during 12 h of dark anaerobic fermentation.     

Indium triflate-catalyzed vinylation of beta-ketoesters with acetylene gas

[reaction: see text]. An In(OTf)(3)-catalyzed addition of a beta-ketoester to acetylene in the presence of molecular sieves produces a alpha-vinylated ketoester in good to excellent yield. The vinylation reaction proceeds without any loss of elements in starting molecules under solvent-free conditions and allows the use of welding-grade acetylene, providing a practical method for synthetic utilization of acetylene gas.