Radiation Temperature Measurement of an Imploded X-Ray Source with a Filtered-Multi-Channel Pinhole Camera

The Plankian radiation temperature of an intense x-ray source driven by imploding spherical CH plastic shell is measured with a filtered-multi-channel pinhole camera. With all the twelve laser beams of the GEKKO-XII laser facility applied, the average radiation temperature is measured to be around 465 eV while the temperature at the core is as high as 818eV. This value is confirmed by other instruments applied.     

Catalytic Asymmetric Synthesis of N‐Chiral Amine Oxides

Direct asymmetric synthesis of N‐chiral amine oxides was accomplished (up to 91:9 e.r.) by means of a bimetallic titanium catalyst. A hydroxy group situated at the γ‐position of the N stereocenter enables the desired N‐oxidation through dynamic kinetic resolution of the trivalent amine substrates. The method was further extended to the kinetic resolution of racemic γ‐amino alcohols with a preexisting stereocenter, giving an important class of enantioenriched (up to 99.9:0.1 e.r.) building blocks that are otherwise difficult to synthesize.     

Selective adsorption of biopolymers on zeolites

Zeolites adsorb biopolymers on their surface and may be suitable as a new type of chromatographic carrier material for proteins, nucleic acids, and their conjugates. We report here various parameters that influence the adsorption of biopolymers on synthesized zeolites with regard to the Si/Al2 ratio and three-dimensional structure. There are three physicochemical principles that may underly the adsorption: 1) below the isoelectric point (pI), mainly Coulombic attraction similar to ion-exchange chromatography; 2) at pI, hydrophobic interactions (a kind of van der Waals attraction) plus the three-dimensional mesopore structure; and 3) above pI, the sum of the Coulombic repulsion and attraction forces, such as the hydrophobic interaction, and also substitution reaction of water on the Al molecule with a protein amino-base. At high Si/Al2 ratio in the presence of a small amount of Al and with mesopores between the zeolite particles, maximal adsorption was seen at pI and was suggested to be dependent on the number of hydrophobic interaction points on the mesopores, and their morphology. The application of zeolites to biochemistry and biotechnology is also discussed.     

Quantum simulation of the t–J model

Computer simulation of a many-particle quantum system is bound to reach the inevitable limits of its ability as the system size increases. The primary reason for this is that the memory size used in a classical simulator grows polynomially whereas the Hilbert space of the quantum system does so exponentially. Replacing the classical simulator by a quantum simulator would be an effective method of surmounting this obstacle. The prevailing techniques for simulating quantum systems on a quantum computer have been developed for purposes of computing numerical algorithms designed to obtain approximate physical quantities of interest. The method suggested here requires no numerical algorithms; it is a direct isomorphic translation between a quantum simulator and the quantum system to be simulated. In the quantum simulator, physical parameters of the system, which are the fixed parameters of the simulated quantum system, are under the control of the experimenter. A method of simulating a model for high-temperature superconducting oxides, the t–J model, by optical control, as an example of such a quantum simulation, is presented.     

Levels in <Superscript>127</Superscript>La fed by the <Superscript>127</Superscript>Ce beta-decay

The low-lying levels in ¹²⁷La have been studied through the -decay of ¹²⁷Ce ( T_1/2 = 29s) produced by bombarding a ^natMo target with a 185-MeV ³⁵Cl beam. Reaction products were on-line mass-separated, and -ray singles and - coincidence measurements were performed. Conversion electrons were also measured and multipolarities of transitions have been derived. The half-life of the 210.9-keV level was determined to be (1.9±0.3)ns by the - delayed coincidence technique. The level scheme obtained has been compared with calculations based on the Nilsson model.     

Prompt chemoenzymatic synthesis of diverse complex-type oligosaccharides and its application to the solid-phase synthesis of a glycopeptide with Asn-linked sialyl-undeca- and asialo-nonasaccharides

We describe herein the preparation of 24 pure asparagine-linked oligosaccharides (Asn-oligosaccharides) from asparagine-linked biantennary complex-type sialylundecasaccharide [(NeuAc-alpha-2,6-Gal-beta-1,4-GlcNAc-beta-1,2-Man-alpha-1,6/1,3-)(2)-Man-beta-1,4-GlcNAc-beta-1,4-GlcNAc-beta-1-asparagine, 2] obtained from egg yolk. Our synthetic strategy aimed at adapting branch specific exo-glycosidases digestion (beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase and alpha-D-mannosidase) of the individual asialo-branch after preparation of monosialyloligosaccharides obtained from 2 by acid hydrolysis of NeuAc. In order to perform branch specific exo-glycosidase digestion, isolation of pure monosialyloligosaccharides obtained was essential. However, isolation of two kinds of monosialyloligosaccharides are difficult by HPLC due to their highly hydrophilic nature. Therefore, we examined chemical protection with hydrophobic protecting (Fmoc and benzyl) groups. These chemical protection enabled us to separate the monosialyloligosaccharides by use of a HPLC column (ODS) on synthetic scales. Using these pure monosialiloligosaccharides enable us to obtain 24 Asn-linked oligosaccharides (100 mg scale) within a few weeks by branch specific exo-glycosidase digestions (alpha-D-neuraminidase, beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase and alpha-D-mannosidase). In addition, solid-phase synthesis of glycopeptide having Asn-linked sialyl-undeca- and asialo-nonasaccharides thus obtained, was also performed on an acid labile HMPA-PEGA resin.     

X-ray photoelectron and X-ray absorption spectroscopic study on β-FeSi2 thin films fabricated by ion beam sputter deposition

A combination of X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) using synchrotron radiation is applied to clarify surface chemical states of β-FeSi₂ films fabricated by an ion-beam sputtering deposition method. The differences in the chemical states of the films fabricated at substrate temperatures of 873, 973 and 1173 K are investigated. For the film fabricated at 873 K, Si 2p XPS spectra indicate the formation of a relatively thicker SiO₂ layer. In addition, Fe L-edge XAS spectra exhibit the formation of FeSi_2−X by preferential oxidation of Si or the presence of unreacted Fe. The results for the film fabricated at 1173 K imply the existence of FeSi₂ with α and ? phases. In contrast, the results for the film fabricated at 973 K indicate the formation of relatively homogeneous β-FeSi₂. These imply that the relatively excellent crystal property of the film fabricated at 973 K is due to the formation of homogeneous β-FeSi₂. As a conclusion, the combination of XPS and XAS using synchrotron radiation is a powerful tool to elucidate the surface chemical states of thin films.     

Solid-state pH ultramicrosensor based on a tungstic oxide film fabricated on a tungsten nanoelectrode and its application to the study of endothelial cells

In this paper, preparation of a novel pH ultramicrosensor and its physiological application has been discussed. A tungsten nanoelectrode was produced by an etching method in 0.1 mol/l NaOH solution at the potential of +0.4 V (versus Ag/AgCl reference electrode) for about 100 s and the diameters ranged from 500 to 800 nm. The pH ultramicrosensor was fabricated by producing WO₃ at W nanoelectrode surface by electrooxidation in 2.0 mol/l H₂SO₄ solution between 1.0 and 2.0 V. At last, Nafion was coated on the surface of WO₃ to protect the pH ultramicrosensor. The W/WO₃ pH ultramicrosensor exhibited a good pH linear region from 2.0 to 12.0 with a super-Nernstian slope of −53.5 ± 0.5 mV/pH unit. Response times ranged from 3 s at about pH 6.0-7.0 up to 15 s at high pH. An interference of various ions to the pH measurement was also studied in this paper. We also studied the lifetime, stability and reproducibility of the W/WO₃ pH ultramicrosensor. In order to testing the performance of W/WO₃ ultramicrosensor, we applied it to measure the extracellular pH values and a pH variation was also given about the normal, damaged and recovery endothelial cells.     

Palladium-catalyzed highly chemo- and regioselective formal [2+2+2] sequential cycloaddition of alkynes: a renaissance of the well known trimerization reaction?

A new concept of highly chemo- and regioselective formation of the benzene ring by a palladium-catalyzed formal [2 + 2 + 2] sequential intermolecular trimerization of alkynes is proposed. Homodimerization of terminal alkynes and subsequent [4 + 2] benzannulation with diynes gives tetrasubstituted benzenes in moderate to good yields. The introduction of two different alkynes (terminal and internal) in the first step of the sequence allows for construction of pentasubstituted benzenes from three different acyclic acetylenic units. In all cases the tetra- and pentasubstituted benzenes are formed as a single reaction product without being accompanied by any of regio- or chemoisomers. A significant acceleration of the sequential trimerization reaction in the presence of Lewis acid/phosphine combined system was observed. Mechanistic studies reveal that the Lewis acid assisted isomerization of the E-enyne formed in the first step of the sequence to the more reactive Z-isomer is responsible for the observed acceleration effect. The proposed methodology provides a conceptually new and synthetically useful route to multifunctional aromatic compounds.     

A short-step synthesis of naphtho[2,3-b]furan-4,9-dione

Phthalic anhydride in THF was added to 3-lithiofuran 2 in THF to give 3,3-di-(3-furyl)-1,3-dihy-droisobenzofuran-1-one 4 . On the other hand, 2 in THF was added to phthalic anhydride in THF to give 2-(3-furanoyl)benzoic acid 3 by the inverse addition method. Further, the parent naphtho[2,3-b]furan-4,9-dione 1 was obtained from the reaction of 3 with two equimolar amounts of LDA.