Structure of cypridina biluciferyl,a dimer of cypridina luciferyl radical having bioluminescent activity

Structure of $\text{Cypridina}$ biluciferyl (luciferyl radical dimer), which is produced by chemical oxidation of $\text{C}$. luciferin with such as ferricyanide, was determined to be the symmetric 5,5′-dimer of $\text{C}$. luciferin. It gives light in the presence of $\text{C}$. luciferase, although the bioluminescent rate is very low. We suggest that the biluciferyl is an intermediate in the oxidation of the luciferin to $\text{C}$. luciferinol.     

A simple technique to measure regional cerebral blood flow during intravascular balloon clamping

A case of giant internal carotid ophthalmic aneurysm was presented. In order to clarify whether the patient could tolerate carotid occlusion, a balloon clamping test was performed. before surgery. The cerebral blood flow was measured using early imaging by single photon emission computed tomography (SPECT) with N-isopropyl-(iodine-123)-p-iodoamphetamine (123I-IMP). When the balloon clamping test was performed the tracer was injected, and scanning was performed 35 minutes after removing the catheter. This tracer enabled a "memory of blood flow" during temporary ischemia to determine the character of quick diffusion and slow wash out, that could not be performed by other methods of cerebral blood flow measurement. SPECT with 123I-IMP can simplify the measurement of cerebral blood flow during the balloon clamping test.     

Glow discharge cleaning of vacuum switch tubes

To clean the surfaces of parts inside a vacuum-switch tube (VST) the authors propose a technique which generates a glow discharge between the inner electrodes and the copper grid surrounding it. Photographic observation reveals that the glow discharge spreads out and cleans the whole surface inside the VST. A breakdown test between the inner electrodes shows the effect of the cleaning with this technique. Higher breakdown voltage between the inner electrodes is attained by performing this glow discharge cleaning in argon rather than hydrogen gas. The difference of the cleaning effect seems to be attributed to that of the energy transfer from ion species to the adsorbed molecules and microprotrusions on the surfaces     

Structure of amipurimycin,a nucleoside antibiotic having a novel branched sugar moiety

Structure of amipurimycin was determined chemically to be $\text{1}$.     

Optimal control of ultrafast selection

Optimal laser control for ultrafast selection of closely lying excited states whose energy separation is smaller than the laser bandwidth is reported on the two-photon transition of atomic cesium; Cs(6S-->7D(J), J=5/2 and 3/2). Selective excitation was carried out by pulse shaping of ultrashort laser pulses which were adaptively modulated in a closed-loop learning system handling eight parameters representing the electric field. Two-color fluorescence from the respective excited states was monitored to measure the selectivity. The fitness used in the learning algorithm was evaluated from the ratio of the fluorescence yields. After fifty generations, a pair of nearly transform-limited pulses were obtained as an optimal pulse shape, proving the effectiveness of the "Ramsey fringes" mechanism. The contrast of the selection ratio was improved by approximately 30% from the simple "Ramsey fringes" experiment.     

Enantioselective total synthesis of (-)- and (+)-petrosin

The enantioselective total synthesis of (-)- and (+)-petrosin is described. The union of two key segments was executed by Suzuki-Miyaura coupling. The quinolizidine rings were stereoselectively constructed via a diastereoselective Mannich reaction and an aza-Michael reaction. The 16-membered ring was constructed by ring-closing metathesis with the second-generation Grubbs catalyst.     

Transition of free-surface flow modes in taylor-couette system

This paper presents our numerical and experimental results of the bifurcation found in Taylor-Couette system with a free surface. The lengths of the two concentric cylinders are finite and their axes are parallel to the direction of the gravitational force. When the end walls of the cylinders are fixed and stationary, numerical and experimental studies have shown that the flow has multiple patterns depending on the cylinder lengths and the Reynolds numbers. Experimental studies on flows with free surfaces also gave various flow modes. Our result shows that the measured and predicted time-dependent displacements of the free surface are in favorable agreement. In case of the cylinder length comparable with the gap width between the cylinders, gradual accelerations of the inner cylinder bring the normal mode flows with one, three and five toroidal vortices. The exchanges of stabilities between these flow modes are summarized in a phase diagram.     

Interfacial de-bonding caused by a screw dislocation pile-up at a circular cylindrical rigid inclusion

An array of continuously-distributed screw dislocations piled up against a circular cylindrical rigid inclusion is analyzed by the complex-variable method. Both uniformly applied shearing load at infinity and internal friction stress opposing the movement of dislocations are taken into account. The pile-up tip is away from the matrix-inclusion interface, its distance from the interface being determined by the condition that the stresses should be finite everywhere in the solid. Stress distributions on the interface are determined, and de-bonding of the interface, namely the formation of initial voids or cracks, is discussed. Stress and displacement near the tip of these initial voids are then analyzed. This analysis is combined with the virtual work argument of A.A. Griffith (1920) to yield a criterion for the initial voids to grow along the interface. The critical void-growth load is expressed by the sum of two terms, one proportional to the friction stress and the other inversely proportional to the square-root of the inclusion radius.     

Calculation of Structures and Deexcitation Process of H2Mu+ Molecules

Energy levels, interparticle distances and dipole transition rates of H₂Mu⁺ molecules were calculated with the coupled rearrangement channel method. The structure of the ground state of H₂Mu⁺ is an isosceles triangle, while that of H₃ ⁺ is an equilateral triangle. The calculated dipole transition rates are small compared with the muon decay rate. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Enhancement of the Formation of Wells–Dawson-Type Polyoxometalates by the Addition of High Concentrations of LiCl

Wells–Dawson-type polyoxometalates are formed by heating an acidic Mo(VI) or W(VI) solution containing significantly higher concentrations of hetero ions, P(V) or As(V), than the ideal molar ratio [M]/[X] = 1/9 (M = Mo, W; X = P, As). Most of the phosphate and arsenate remains unreacted in the reaction mixture. These reaction conditions are unusual, even though more reagents than the stoichiometric amounts are frequently needed to obtain complete reactions. In the present study, the replacement of a large amount of unreacted hetero ions containing salts by normal ions (salts) was investigated. The formation of Wells–Dawson-type polyoxometalates, [X₂M₁₈O₆₂]^6? (X = P, As; M = Mo, W), in the presence of LiCl and NaCl was investigated by Raman spectroscopy and ³¹P NMR in aqueous solution. The addition of LiCl enhanced the formation of Wells–Dawson-type polyoxometalates, which formed under solution conditions close to the ideal molar ratio [M]/[X] = 1/9.