Schizophyllans carrying oligosaccharide appendages as potential candidates for cell-targeted antisense carrier

Schizophyllans carrying beta-lactoside and alpha-mannoside appendages were prepared from native schizophyllan through NaIO4 oxidation followed by reductive amination using aminoethyl-beta-lactoside and alpha-mannoside, respectively. The resulting schizophyllans form stable macromolecular complexes with polynucleotides, such as poly(C) and poly(dA). Specific affinity between these macromolecular complexes and saccharide-binding proteins was demonstrated by surface plasmon resonance and agarose gel staining assays. beta-lactoside-appended schizophyllan enhanced an antisense activity in hepatocytes which express lactoside-binding proteins on their cell surfaces.     

Rhodium-catalyzed asymmetric 1,6-addition of aryltitanates to enynones giving axially chiral allenes

[reaction: see text] The addition of aryltitanate reagents ArTi(OPr-i)4Li to 3-alkynyl-2-en-1-ones in the presence of chlorotrimethylsilane and a rhodium-(R)-segphos as a catalyst proceeded in a 1,6-fashion to give a high yield of axially chiral allenylalkenyl silyl enol ethers with up to 93% ee.     

A p-phosphinophenolate ligand for the palladium-catalysed arylation of alkenes

A triphenylphosphine having a strong electron-donating group, an oxyanion, at the para position of one of the benzene rings was found to show much higher efficiency compared with other structurally related triarylphosphines in the palladium-catalysed arylation of alkenes.     

Direct time-domain observation of ultrafast dephasing in adsorbate-substrate vibration under the influence of a hot electron bath: Cs adatoms on Pt(111)

The stretching vibration of Cs adsorbed on Pt(111) is excited coherently by resonant stimulated Raman excitation and its time evolution is probed by fs time-resolved second harmonic generation as a function of pump laser fluence I. As I increases, a fast dephasing component with the lifetime of tau=0.7 ps grows, being superimposed on a slow one with tau=1.9 ps. The fast component is a manifestation of pure dephasing caused by elastic and inelastic scattering of hot electrons at adsorbate.     

Wavefront Curvature Sensing Based on Diffraction Grating and Fractional Fourier Transforms

We propose a new concept for wavefront curvature sensing, which is based on diffraction grating and fractional Fourier transforms systems. An explicit formula is derived expressing the wavefront curvature, and the wavefront shape can also be retrieved rapidly. The experimental setup is presented and numerical simulations show the validity of the proposed method.     

Direct preparation of allylic zirconium reagents from zirconocene-olefin complexes and alkenes

A novel method for preparation of allylic zirconium reagents directly from 1-alkenes via zirconocene-olefin complex has been developed. Selective transfer of the hydride of zirconocene allyl hydride complex, a tautomer of zirconocene-olefin complex, to diisopropyl ketone generates the corresponding zirconocene alkoxide allyl. The allylic zirconium reagents formed effects stereoselective allylation of aldehyde at 25 degrees C and -78 degrees C to provide syn- and anti-homoallyl alcohols, respectively. The anti-isomer is formed via a six-membered chair transition state under kinetic control. The syn-selectivity can be rationalized by considering isomerization of the anti-adduct by a retroallylation process.     

Mechanically Strain-Induced Modification of Selenium Powders in the Amorphization Process

For the fabrication of particles designed in the nanoscale structure, or the nanostructural modification of particles using mechanical grinding process, selenium powders ground by a planetary ball mill at various rotational speeds have been investigated. Structural analyses, such as particle size distributions, crystallite sizes, lattice strains and nearest neighbour distances were performed using X-ray diffraction, scanning electron microscopy and dynamical light scattering.By grinding powder particles became spherical composites consisting of nanocrystalline and amorphous phase, and had a distribution with the average size of 2.7 m. Integral intensities of diffraction peaks of annealed crystal selenium decreased with increasing grinding time, and these peaks broadened due to lattice strains and reducing crystallite size during the grinding. The ground powder at 200 rpm did not have the lattice strain and showed amorphization for the present grinding periods. It indicates that the amorphization of Se by grinding accompanies the lattice strain, and the lattice strain arises from a larger energy concerning intermolecular interaction. In this process, the impact energy is spent on thermal and structural changes according to energy accumulation in macroscopic (the particle size distribution) and microscopic (the crystallite size and the lattice strain) range.     

The electron trap associated with an anion vacancy in ZnSe and ZnSxSe1−x

A dominant electron trap in ZnSe and ZnS_xSe_1?x has been studied by DLTS. The trap depth of about 0.3 eV is independent of the crystal growth, doped impurities and S mole fraction x in ZnS_xSe_1?x, while the electron-capture cross-section decreases with x. These properties indicate that the electron trap is due to the anion vacancy in ZnSe and ZnS_xSe_1?x.     

Highly sensitive spectrofluorometry of europium(III) as its benzoyltrifluoroacetone complex with trioctylphosphine oxide by means of solvent extraction and vacuum sublimation

Summary A new method for the highly sensitive fluorometric determination of europium(III) as its benzoyltrifluoroacetone (BFA) complex with trioctylphosphine oxide (TOPO) without uncombined BFA in n-hexane has been established by means of solvent extraction and vacuum sublimation. The effect of various factors on the fluorescence intensity of europium(III) was investigated. The fluorescence intensity was measured at 620 nm against rhodamine B as an internal standard under the excitation at 335 nm. It was found that a heating treatment gave rise to the enhancement of the fluorescence intensity for about twice times compared with that without heating treatment. Excellent linearity of the calibration curve of europium(III) was obtained in the range of 0–100 ppb. A few ppb of europium(III) can still be detected with this method. All 13 rare earth metals and cobalt(II) tested gave a somewhat positive error. Aluminium(III), iron(III), and copper(II) caused a negative error. The interference of aluminium(III) and iron(III) was removed by extraction with 0.1 mol/l 8-quinolinol in chloroform at pH 4.0, while the problem of cobalt(II) and copper(II) was solved by masking with 0.1 mol/l Na₂S₂O₃ in aqueous solution.

---

Hochempfindliche spektrofluorimetrische Bestimmung von Europium(III) als Benzoyltrifluoracetonkomplex mit Trioctylphosphinoxid mit Hilfe der Lösungsextraktion und Vakuumsublimation