Passivation effects of deuterium exposure on boron-doped CVD homoepitaxial diamond

The deuterium (hydrogen) passivation effect on acceptors in boron-doped CVD homoepitaxial diamond was studied by electrical (Hall-effect) and secondary ion mass spectroscopy (SIMS) measurements. Deuterium was incorporated into the samples using microwave (MW) deuterium plasma at 673 K for 2–24 h. We observed the progress of acceptor passivation with p-type conduction, which finally resulted in a highly resistive state.     

Electromagnetic shielding of HF lamps using wire structures:simulation and measurement

High-frequency (HF) operated lamps, such as HF fluorescent lamps, have several advantages over conventional ones but they contaminate the environment with their EM field emissions. The shielding of the electromagnetic emission should be realized without much effect on the emission of the light. Enclosing the lamps in a housing made of widely spaced thin wires could be an appropriate way to shield the electromagnetic field. The paper studies the effectiveness of some wire structures for shielding the electromagnetic emission from HF fluorescent lamps. An analytical study, method of moments (MoM), and measurements have been carried out to evaluate the strength of the near-field and the shielding effectiveness of the structures     

Colorimetric microdetermination of sulphites in foods by use of the modified rankine apparatus. IV.

Summary Detection and determination of traces of sulphites in foods was attempted by use of the modified Rankine apparatus and pararosaniline colorimetry. Replacement of alkaline titration reported previously by pararosaniline colorimetry lowered the absolute detection limit from 30 g (titration method) to 2 g. In view of clean analysis, in the color developing system, 0.1 N-sodium hydroxide was used in place of mercuric chloride solution commonly used as an absorbant of sulphites. In order to prevent oxidative decomposition of sulphites during operation, nitrogen gas was used as carrier instead of air. Dimedone and sodium azide were used for the elimination of aldehydes and nitrites, respecitvely, in the sample, which will disturb the color development of sulphites with pararosaniline-formaldehyde reagents. With this improved method, it was possible to determine the residual sulphites in frozen peeled shrimps, sugared beans and other foods with low sulphite contents accurately.

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Colorimetrische Mikrobestimmung von Sulfiten in Lebensmitteln bei Anwendung der modifizierten IV. Rankine Apparatur

Zusammenfassung Geringe Sulfitmengen in Lebensmitteln (geschälte Garnelen, gezuckerte Bohnen) können colorimetrisch bestimmt werden. Die neuentwickelte Methode beruht auf einer Kombination von colorimetrischer Bestimmung mittels p-Rosanilin und der Bestimmungsmethode nach Rankine. Auf diese Weise lassen sich Gehalte von 2 g noch genau bestimmen. Bei der Farbentwicklung wurde das giftige Quecksilbertetrachlorid durch 0.1 n-NaOH ersetzt, anstelle von Luft Stickstoff als Trägergas verwendet und somit eine Oxydation des Sulfits während der Bestimmung vermieden. Da Nitrit und Aldehyde die Farbentwicklung stören, wurde ihr Einfluß durch Dimedon und Natriumazid ausgeschaltet.

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Studies on the Analyses of Sulphites in Foods (IV)     

Uterine Deletion of Bmal1 Impairs Placental Vascularization and Induces Intrauterine Fetal Death in Mice

Recently, it was demonstrated that the expression of BMAL1 was decreased in the endometrium of women suffering from recurrent spontaneous abortion. To investigate the pathological roles of uterine clock genes during pregnancy, we produced conditional deletion of uterine Bmal1 (cKO) mice and found that cKO mice could receive embryo implantation but not sustain pregnancy. Gene ontology analysis of microarray suggested that uterine NK (uNK) cell function was suppressed in cKO mice. Histological examination revealed the poor formation of maternal vascular spaces in the placenta. In contrast to WT mice, uNK cells in the spongiotrophoblast layer, where maternal uNK cells are directly in contact with fetal trophoblast, hardly expressed an immunosuppressive NK marker, CD161, in cKO mice. By progesterone supplementation, pregnancy could be sustained until the end of pregnancy in some cKO mice. Although this treatment did not improve the structural abnormalities of the placenta, it recruited CD161-positive NK cells into the spongiotrophoblast layer in cKO mice. These findings indicate that the uterine clock system may be critical for pregnancy maintenance after embryo implantation.     

Excitation density dependence of luminescence spectrum of electron-hole plasma in diamond

Time-resolved band edge luminescence spectrum in IIa diamond has been measured with the 5th harmonics of a pulsed YAG laser (5.82 eV) and an ICCD image intensifier of 5 ns gate width at 290 K. The time-resolved luminescence spectrum is decomposed into three components of free exciton (FE), excitonic complex (EC) and electron-hole plasma (EHP). The decay times of the FE and EC luminescence are 45 and 27 ns, respectively and that of the EHP luminescence has been seen to be shorter than the gate width, 5 ns. The low energy onset of the EHP luminescence spectrum has been observed to decrease with increasing excitation density and attains the onset of the electron-hole drop luminescence spectrum at the excitation density of 0.6 J/cm², at which the electron-hole pair density is 1.2 × 10²⁰ cm^? 3. Furthermore, the excitation density dependences of the FE, EC and EHP luminescence intensities are explained with the percolation theory.     

Morphological changes of Candida albicans induced by micafungin (FK463), a water-soluble echinocandin-like lipopeptide

Micafungin (FK463), a novel water-soluble echinocandin-like lipopeptide, exerted fungicidal action toward growing cells of Candida albicans at concentrations of 0.1 microg ml(-1) or above. The drug at these levels induced osmotically fragile cells and the resulting fungicidal effect was partially reversed when cultures were grown in the presence of an osmotic stabilizer. Candida cells incubated with fungicidal concentrations of micafungin gradually increased in size and/or became deformed. An electron microscopic study of such micafungin-treated cells revealed morphological alterations in the cell wall; deformation in contour, abnormal septum formation and decrease in thickness of the intermediate layer of the cell wall were prominent. In addition, the structure of cell membranes as well as of membranous cytoplasmic organelles was slightly impaired. These data suggest that micafungin principally affects the normal formation of the cell wall in growing Candida cells.     

Crystallographic Orientation Dependence of the Schottky Properties of Au/SrTiO3 Junctions

Crystallographic orientation dependence of the Schottky properties of Au/Nb-doped SrTiO₃ (STO:Nb) junctions has been investigated using single crystals of STO:Nb (1 0 0) and (1 1 1). It is found from electrical properties that the Schottky barrier height (SBH) of the Au/STO:Nb junctions estimated from current density (J)-voltage (V) characteristics shows crystallographic orientation dependence, while the flat band voltage estimated from capacitance (C)-voltage (V) characteristics is independent of the orientation. Displacement currents originated from the junction capacitance have been clearly observed at reverse bias voltage even in a condition of dV/dt 8.75 × 10^–3 [V/s] because of large electrostatic permittivity of the STO, and the displacement currents also showed crystallographic orientation dependence. The different response in the electrical properties of the Schottky junctions suggests that electric properties of intrinsic low permittivity layers, which exist at Au/STO:Nb interfaces, have the crystallographic orientation dependence.     

Production and performance of the inFOCmicroS 20-40-keV graded multilayer mirror

The International Focusing Optics Collaboration for microCrab Sensitivity (InFOCmicroS) balloonborne hard x-ray telescope incorporates graded Pt/C multilayers replicated onto segmented Al foils to obtain the significant effective area at energies previously inaccessible to x-ray optics. Reflectivity measurements of individual foils demonstrate our capability to produce a mass quantity of multilayered foils with a rms roughness of 0.5 nm. The effective area of the completed mirror is 78 and 22 cm2 at 20 and 40 keV, respectively. The measured half-power diameter is 2.0 +/- 0.6 are min (90% confidence). The successful completion of this mirror demonstrates its applicability to future x-ray telescopes such as Constellation-X.     

Transport of single cells using an actin bundle-myosin bionanomotor transport system

The potential of using actin bundles for the transport of liposomes and single cells across myosin-coated surfaces is investigated. Compared to that observed with filamentous actin, the liposome transport using actin bundles was more linear in nature and able to occur over longer distances. Bundles, but not filamentous actin, were capable of moving single cells. Cargo unloading from bundles was achieved by incubation with Triton X-100. These data suggest that actin bundling may improve the ability of the myosin motor system for nanotransport applications.     

Electrical characterization of homoepitaxial diamond p–n junction

Electrical properties of homoepitaxial diamond p–n⁺ junction of boron (B)-doped p-type layer and phosphorus-doped n-type layer on Ib (111) diamond single crystal have been characterized. Current–voltage characteristics show a clear rectifying property with rectification ratio of over 10⁵ at ± 10 V. From capacitance–voltage characteristics, it is found that a spatial distribution of space-charge density N_i of the p–n⁺ junction is not uniform and N_i at a middle region of the space-charge layer formed at zero bias voltage is higher than that of other region of the space-charge layer. This peculiar characteristic can be explained by superposition of two effects; one is the deep dopant effect due to B atoms in the p-type layer, which makes to reduce N_i at around the edge of the space-charge layer formed at zero bias voltage. The other is the compensation of B acceptors by impurity atoms diffusing during the p–n⁺ interface and incorporating during the growth of p-type layer, which makes to reduce N_i at the vicinity of the p–n⁺ interface.