Deposition of Diamond-Like Carbon Film and Mass Spectrometry Measurement in CH4/O2 RF Plasma

The deposition of diamond-like carbon (DLC) film and the measurements of ionic species by means of mass spectrometry were carried out in a CH ₄ /O ₂ RF (13.56 MHz) plasma. The film deposition rate greatly decreased with increasing O ₂ content up to 10% O ₂ . The oxygen ion density indicated the remarkable increase with the increase of O ₂ content up to 10%. The hydrocarbon ion density is increased considerably by the addition of 5% O ₂ , and then decreased monotonically for O ₂ contents more than 5%. Many oxygenated hydrocarbon ions were detected in the CH ₄ /O ₂ plasma. They were classified into three kinds of ions: C _n H _m O ⁺ , C _n H _m OH ⁺ , and C _n H _m O ₂ H ⁺. When the O ₂ content was increased, the higher hydrocarbon C _n H _m ⁺ (n2) ion densities (except C ₂ H ₄ ⁺ ) decreased more than the principal (CH ₃ ⁺ and CH ₄ ⁺ ) ion densities, since the generation of higher hydrocarbon ions would be suppressed by the formation of oxygenated hydrocarbons. It was also suggested that the great decrease in the film deposition rate in the CH ₄ /O ₂ plasma was mainly associated with considerable decrease in the higher hydrocarbon ion densities. The properties of DLC film obtained in CH ₄ /O ₂ plasma did not indicate considerable change from those obtained in pure CH ₄ plasma.     

Total synthesis of escherichia coli lipid A

The first total synthesis of E. coli lipid A ($\text{1}$) is described. The synthetic compound was identical with a natural specimen and exhibited the full endotoxic activity. It was thus conclusively proved by this chemical synthesis that lipid A is the active principle of bacterial endotoxin.     

Fluorescence study on the nyctinasty of Phyllanthus urinaria L. using novel fluorescence-labeled probe compounds

We report the synthesis of fluorescence-labeled probes based on phyllanthurinolactone 1, which is a leaf-closing substance of Phyllanthus urinaria L. The fluorescence study using biologically active probe 2 and inactive probes (epi-2 and 31) revealed that the target cell for 1 is a motor cell and suggested that some receptors, which recognize the aglycon of 1 exist on the plasma membrane of the motor cell, as with leaf-opening substances. Moreover, binding of probe 2 was specific to the plant motor cell contained in the plants belonging to the genus Phyllanthus. These results showed that the binding of probe 2 with a motor cell is specific to the plant genus and suggested that the genus-specific receptor for the leaf-closing substance would be involved in nyctinasty.     

Tetrabutylammonium fluoride-promoted α-[C]methylation of α-arylesters: a simple and robust method for the preparation of C-labeled ibuprofen

Tetrabutylammonium fluoride-promoted α-[¹¹C]methylation of α-arlylesters was developed. The method was amenable to the remote-controlled synthesis of ¹¹C-labeled ibuprofen.     

The computation of the logarithmic cohomology for plane curves

We will give algorithms of computing bases of logarithmic cohomology groups for square-free polynomials in two variables.     

Enantio-differential approach using fluorescence-labeled phyllanthurinolactone, a leaf-closing factor of Phyllanthus urinaria L.

We report here the synthesis of enantio-pair-type fluorescence-labeled probes based on phyllanthurinolactone (1), which is a leaf-closing substance of Phyllanthus urinaria L. Moreover, the application of an enantio-differential approach to distinguish between specific and nonspecific binding of ligands and receptors was performed. Fluorescence studies using a natural-type probe 6 and a nonnatural-type probe 7 revealed that the target cell for 1 is a motor cell. Furthermore, our results lead to the suggestion that some receptors, which recognize the stereochemistry of the aglycon of 1, exist on the plasma membrane of the motor cell, as do leaf-opening substances.     

Enhanced tunnel magnetoresistance due to spin dependent quantum well resonance in specific symmetry states of an ultrathin ferromagnetic electrode

Spin dependent quantum well resonance has been investigated in fully epitaxial magnetic tunnel junctions with Fe(001)/MgO(001)/ultrathin Fe(001)/Cr(001) structure. The dI/dV spectra clearly show the resonant peaks which shift systematically depending on the thickness of an ultrathin electrode as predicted in ab initio calculation [Zhong-Yi Lu et al, Phys. Rev. Lett. 94, 207210 (2005)]. The magnetotransport is strongly modulated at the same bias voltage as the resonant peaks. This control of the magnetotransport in magnetic tunnel junctions at a specific bias voltage will contribute to the development of active spintronic devices.