Molecular beam epitaxial growth of SrO and CaO with RHEED intensity oscillation

SrO and CaO, related compounds of BSCCO superconductor, are grown onto SrTiO₃(100) substrates with molecular beam epitaxy(MBE) technique. During growth, the specular spots of RHEED patterns show intensity oscillations, indicating two dimensional growth. The periods of oscillations are utilized to calculate the atom fluxes. It is shown that sublimation processes of both Sr and Ca metals in the effusion cells are stable under the growth condition of oxide films. The periods of oscillations during the SrO growth are independent of substrate temperature, confirming that Sr atoms are oxidized immediately and stay on the substrate surface without re-evaporation. These informations are practically available for precise control of the atomic layer controlled MBE of BSCCO superconductor thin films.On leave from Superconductiivity Research Laboratory, ISTEC.     

Fabrication of TiO2-based transparent conducting oxide on glass and polyimide substrates

We report on preparation and properties of anatase Nb-doped TiO₂ transparent conducting oxide films on glass and polyimide substrates. Amorphous Ti_0.96Nb_0.04O₂ films were deposited at room temperature by using sputtering, and were then crystallized through annealing under reducing atmosphere. Use of a seed layer substantially improved the crystallinity and resistivity (ρ) of the films. We attained ρ = 9.2 × 10^− 4 Ω cm and transmittance of ~ 70% in the visible region on glass by annealing at 300 °C in vacuum. The minimum ρ of 7.0 × 10^− 4 Ω cm was obtained by 400 °C annealing in pure H₂.     

Boron-dependent regulation of translation through AUGUAA sequence in yeast

Under high boron (B) conditions, nodulin 26-like intrinsic protein 5;1 (NIP5;1) mRNA, a boric acid channel, is destabilized to avoid excess B entry into roots of Arabidopsis thaliana. In this regulation, the minimum upstream open reading frame (uORF), AUGUAA, in its 5′-untranslated region (5′-UTR) is essential, and high B enhances ribosome stalling at AUGUAA and leads to suppression of translation and mRNA degradation. This B-dependent AUGUAA-mediated regulation occurs also in animal transient expression and reticulocyte lysate translation systems. Thus, uncovering the ubiquitousness of B-dependent unique regulation is important to reveal the evolution of translational regulation. In the present study, we examined the regulation in Saccharomyces cerevisiae. Reporter assay showed that in yeast, carrying ATGTAA in 5′-UTR of NIP5;1 upstream of the reporter gene, the relative reporter activities were reduced significantly under high B conditions compared with control, whereas deletion of ATGTAA abolished such responses. This suggests that AUGUAA mediates B-dependent regulation of translation in Saccharomyces cerevisiae. Moreover, the deletion of ATGTAA resulted in up to 10-fold increase in general reporter activities indicating the suppression effect of AUGUAA on translation of the main ORF. Interestingly, mRNA level of the reporter gene was not affected by B in both yeast cells with and without AUGUAA. This finding reveals that in yeast, unlike the case in plants, mRNA degradation is not associated with AUGUAA regulation. Together, results suggest that B-dependent AUGUAA-mediated translational regulation is common among eukaryotes.     

Three Dimensional Wavepacket Simulation on the H Atom Scattering for the Full Reaction of CF3H + Ar (3P) → CF3* + H + Ar

Three dimensional (3D) wavepacket simulation on the H atom scattering is carried out for a full reaction of CF₃H + Ar(³P) → CF₃* + H + Ar for the H-end orientation since our previous study on the 2D wavepacket simulation showed a quantum interference effect only for collisions at the H-end of CF₃H. We treat the present 3D wavepacket simulation in a time-dependent SCF (TDSCF) scheme, which enables us to reduce 3D to a coupled two and one dimensional (2D+1D) problem. The initial wavepacket of CF₃H is prepared in the lowest rotational state, i.e., |JKM > = |111>. The calculated snapshots of the scattered wavepacket for the Fiend orientation show a clear quantum interference effect again in the angular distribution of the product H atom due to the so-called one-atom cage effect on the heavy-light-heavy collision configuration. Thus the present simulation suggests that a continuous wave character of the wavepacket would be responsible for such a relatively clear interference effect in the full reaction, unlike a blurred interference effect with a pulse-type of wavepacket excitation in the half reaction.     

Railgun pellet injection system for fusion experimental devices

A railgun pellet injection system has been developed for fusion experimental devices. Using a low electric energy railgun system, hydrogen pellet acceleration tests have been conducted to investigate the application of the electromagnetic railgun system for high speed pellet injection into fusion plasmas. In the system, the pellet is pre-accelerated before railgun acceleration. A laser beam is used to induce plasma armature. The ignited plasma armature is accelerated by an electromagnetic force that accelerates the pellet. Under the same operational conditions, the energy conversion coefficient for the dummy pellets was around 0.4%, while that for the hydrogen pellets was around 0.12%. The highest hydrogen pellet velocity was 1.4 km s⁻¹ using a 1 m long railgun. Based on the findings, it is estimated that the hydrogen pellet has the potential to be accelerated to 5 km s⁻¹ using a 3 m long railgun.     

Expression of erythroid-specific genes in acute megakaryoblastic leukaemia and transient myeloproliferative disorder in Down's syndrome

Acute megakaryoblastic leukaemia (M7) and transient myeloproliferative disorder in Down's syndrome (TMD) are characterized by rapid growth of abnormal blast cells which express megakaryocytic markers. To clarify properties of the blast cells in M7 and TMD cases, we examined erythroid markers expression in blasts from six cases with M7 and seven cases with TMD in this study. Erythroid-specific mRNAs encoding gamma-globin and erythroid delta-aminolevulinate synthase were found to be expressed in blasts from most of these cases, indicating that majorities of the blasts in M7 and TMD cases have erythroid and megakaryocytic phenotypes. We also found that mRNAs encoding GATA-1 and GATA-2 are expressed in all these cases. These results suggest that M7 blasts and TMD blasts correspond to the erythroid/megakaryocytic bipotential progenitor cells.     

Colon cancer with a high serum alpha-fetoprotein level

We report on a patient with colon cancer and a very high serum alpha-fetoprotein level. This 75-yr-old man presented with right lower quadrant abdominal pain. An abdominal CT scan as well as ultrasonography showed a tumor in the cecum. Serum alpha-fetoprotein level was extremely high (3,070 ng/ml). At laparotomy, a large mass was found in the cecum, and a right hemicolectomy was performed. Histological examination, including immunohistochemical study, showed an adenocarcinoma of the colon producing alpha-fetoprotein.     

Cryopreservation of expanded mouse blastocysts by vitrification in ethylene glycol-based solutions

Experiments were conducted to find optimal conditions for obtaining high survival of expanded mouse blastocysts after vitrification. The vitrification solutions used were designated EFS20, EFS30 and EFS40, and contained 20%, 30% and 40% ethylene glycol, respectively, diluted in PB1 medium containing 30% Ficoll plus 0.5 mol sucrose l-1. In the toxicity test of the solutions and each cryoprotectant, ethylene glycol was found to be toxic to embryos. For vitrification, expanded blastocysts were exposed to the vitrification solutions at 10, 20 or 25 degrees C for various periods; they were then cooled rapidly in liquid nitrogen, after which they were warmed rapidly. When the embryos were directly exposed to EFS40 at 20 degrees C for 2 min before vitrification, 66% of them re-expanded during 48 h of post-warming culture. The re-expansion rates decreased when exposure time was shortened (0.5 min), when exposure temperature was lowered (10 degrees C), or when embryos were vitrified in EFS20 and EFS30, although these conditions should be less toxic. When embryos had been pretreated in a dilute (10-20%) ethylene glycol solution for 5 min, followed by short exposure (0.5 min) to EFS40 at 20 degrees C, post-vitrification survival rate increased to 83-84%; furthermore, the rate reached 94% when the temperature was increased to 25 degrees C. Expanded blastocysts cryopreserved by this two-step method developed into live young as well as control embryos after transfer.(ABSTRACT TRUNCATED AT 250 WORDS)