Regulation of cell growth-dependent expression of mammalian CDC6 gene by the cell cycle transcription factor E2F

CDC6 of Saccharomyces cerevisiae regulates the DNA replication initiation through the origin recognition complex (ORC). Identification of a human homolog of the CDC6 gene (HsCdc6) suggests a universal role of the gene product in DNA replication. Expression of HsCdc6 is growth-regulated. We investigated the molecular basis of growth-regulated expression of mammalian Cdc6. The promoter activity of isolated HsCdc6 upstream region was activated at late G1 and G1/S boundary in the cell cycle of rat embryonic fibroblast REF52 cells by the addition of serum. The isolated promoter was activated by exogenous expression of E2F without serum stimulation. However a mutant promoter lacking the E2F recognition sites failed to respond to serum stimulation and exogenous expression of E2F. Expression of endogenous Cdc6 was induced by exogenous expression of E2F. Therefore, we concluded that the growth-regulated expression of mammalian Cdc6 was mediated by E2F. Moreover, we demonstrated that exogenous overexpression of either HsCdc6 or HsOrc1 failed to induce DNA synthesis unlike overexpression of E2F1, even though E2F1 induced both Cdc6 and Orc1, suggesting that E2F may regulate the expression of another gene(s), besides Cdc6 and Orc1, required for induction of cellular DNA synthesis in mammalian cells.     

Clinicopathological analysis and therapy in hepatitis C virus-associated nephropathy

The authors evaluated, using computer image analysis system, 15 renal biopsy specimens from patients with MCD and 15 from patients with FSGS. As a control group 5 biopsy and 10 autopsy renal specimens were used. These studies revealed, that in MCD glomeruli showed proliferative changes unrecognizable by light microscopy. In FSGS glomeruli without sclerotic changes were larger than in controls and showed glomerular cells proliferation (per unit of glomerular area) similar to MCD. FSGS in comparison with MCD showed larger glomeruli and prominent interstitial fibrosis. These observations appeared to be helpful in distinguishing MCD and recent forms of FSGS. There were no correlations between relative interstitial volume and glomerular changes in MCD as well as in FSGS. The authors concluded, that histomorphometry can't be used instead of morphological examinations of renal biopsy specimens, but it gives objective informations about progression of the illness and may be useful in differential diagnosis of selected cases of MCD and FSGS.     

Perfect Bi4Ti3O12 Single‐Crystal Films via Flux‐Mediated Epitaxy

Excellent crystallinity of material films and atomic control of their surface/interface, sufficient for the realization of their optimal physical properties, are technological premises for modern functional‐device applications. Bi₄Ti₃O₁₂ and related compounds attract much interest as highly insulating, ferroelectric materials for use in ferroelectric random‐access memories. However, it has been difficult thus far for Bi₄Ti₃O₁₂ films to satisfy such requirements when formed using vapor‐phase epitaxy, owing to the high volatility of Bi in a vacuum. Here, we demonstrate that flux‐mediated epitaxy is one of the most promising and widely applicable concepts to overcome this inevitable problem. The key point of this process is the appropriate selection of a multi‐component flux system. A combinatorial approach has led to the successful discovery of the novel flux composition of Bi–Cu–O for Bi₄Ti₃O₁₂ single‐crystal film growth. The perfect single‐crystal nature of the stoichiometric Bi₄Ti₃O₁₂ film formed has been verified through its giant grain size and electric properties, equivalent to those of bulk single crystals. This demonstration has broad implications, opening up the possibility of preparing stoichiometric single‐crystal oxide films via vapor‐phase epitaxy, even if volatile constituents are required.     

Creep cavity growth under interaction between lattice diffusion and grain-boundary diffusion

A model and a method of numerical analysis of the cavity growth in grain boundaries in metals due to lattice diffusion are proposed. The growth behavior simulated is compared to that due to grain-boundary (GB) diffusion. The simulation method is extended to analyze the growth under the interaction between lattice diffusion and GB diffusion. The growth rate calculated under the interaction is approximately equal to the linear sum of those due to the pure lattice diffusion and the pure GB diffusion.     

Phase equilibria and thermodynamic properties of Sn-Ag based Pb-free solder alloys

We have recently developed a thermodynamic database for micro-soldering alloys, alloy database for micro-solders (ADAMIS). ADAMIS which consists of the elements Ag, Bi, Cu, In, Pb, Sb, Sn, and Zn has been constructed by the calculation of phase diagrams (CALPHAD) method. The thermodynamic parameters for describing the Gibbs energy of the liquid and solid phases have been evaluated by optimizing the experimental data on phase boundaries and thermo-chemical properties. In this paper, the phase equilibria and the related thermodynamic properties pertaining to the Sn-Ag-X (X=Bi, In, Cu, and Zn) alloys are examined using ADAMIS. Typical examples of the isothermal and vertical section phase diagrams, liquidus surface, etc. for these promising lead-free solders are presented. In addition, ADAMIS is also applied to calculate the nonequilibrium solidification process using the Scheil model.     

Repeated temperature modulation epitaxy for p-type doping and light-emitting diode based on ZnO.

Since the successful demonstration of a blue light-emitting diode (LED), potential materials for making short-wavelength LEDs and diode lasers have been attracting increasing interest as the demands for display, illumination and information storage grow. Zinc oxide has substantial advantages including large exciton binding energy, as demonstrated by efficient excitonic lasing on optical excitation. Several groups have postulated the use of p-type ZnO doped with nitrogen, arsenic or phosphorus, and even p-n junctions. However, the choice of dopant and growth technique remains controversial and the reliability of p-type ZnO is still under debate. If ZnO is ever to produce long-lasting and robust devices, the quality of epitaxial layers has to be improved as has been the protocol in other compound semiconductors. Here we report high-quality undoped films with electron mobility exceeding that in the bulk. We have used a new technique to fabricate p-type ZnO reproducibly. Violet electroluminescence from homostructural p-i-n junctions is demonstrated at room-temperature.     

Over 1.3 /spl mu/m CW laser emission from InGaSb quantum-dot vertical-cavity surface-emitting laser on GaAs substrate

An Sb-based quantum-dot vertical-cavity surface-emitting laser (QD-VCSEL) operating in the 1.3 /spl mu/m optical communication waveband is presented. A QD-VCSEL containing high-density InGaSb QDs in the active region is fabricated on GaAs substrate. The density of InGaSb QDs is drastically increased using a new method of an Si atom irradiation technique. A long-wavelength laser emission at 1.34 /spl mu/m is successfully achieved on the InGaSb QD-VCSEL in CW operation at room temperature.     

Optimization of excimer-forming two-probe nucleic acid hybridization method with pyrene as a fluorophore

A previously presented homogeneous assay method, named the excimer-forming two-probe nucleic acid hybridization (ETPH) method, is based on specific excimer formation between two pyrenes attached at the neighboring terminals of two sequential probe oligonucleotides complementary to a single target. In this study, we investigated assay conditions and optimal molecular design of probes for intense excimer emission using a pyrenemethyliodoacetamide-introduced 16mer probe, a pyrene butanoic acid-introduced 16merprobe and a target 32mer. The length of the linker between the pyrene residue and the terminal sugar moiety remarkably influenced the quantum efficiency of excimer emission; the pair of linker arms of these two probes was optimal. The quantum efficiency was also dependent upon the concentrations of dimethylformamide and NaCl added to the assay solution. Spectroscopic measurements and T m analysis showed that an optimal configuration of the two pyrene residues for intense excimer emission might be affected by pyrene-pyrene interaction, pyrene-duplex interaction (intercalation/stacking) and solvent conditions as a whole. We then demonstrated the practicality of the ETPH method with the optimal hybridization conditions thus attained by determining that the concentration of 16S rRNA in extracts from Vibrio mimicus ATCC 33655 cells in exponential growth phase is 18 500 16S rRNA molecules/cell on average.     

Isolation of bioactive compounds from Helix aspersa nerve tissue and the effect of pQPPLPRYamide on heart, esophagus and central neurons of H. aspersa and rectum of Anodonta woodiana

1. Tumour necrosis factor-alpha (TNF-alpha) is implicated in the pathogenesis of many pulmonary and airway diseases. TNF-alpha stimulation may release interleukin-8 (IL-8) in airways mediated via an increase in intracellular oxidant stress. In the present study, we have assessed leukosequestration and IL-8 release in the airways in response to intratracheal administration of human recombinant TNF-alpha, and examined the modulatory role of endogenous NO by pretreatment with a NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME). 2. TNF-alpha (10(2)-10(-4) u) was administered intratracheally in male guinea-pigs which were anaesthetized with urethane and were ventilated artificially. TNF-alpha induced a time- and dose-related increase in neutrophil numbers and a concomitant increase in human IL-8 equivalent level retrieved from bronchoalveolar lavage (BAL) with the peak effect at 10(3) u at 6 h of TNF-alpha injection (late phase). Intratracheal administration of recombinant human (rh)IL-8 (0.025, 0.25, 2.5 ng) producing a similar range of human IL-8 equivalent levels in BAL as measured in our results induced neutrophil recovery in BAL fluid to a similar extent. Administration of anti-IL-8 antibody prevented the late phase of neutrophil recruitment induced by TNF-alpha or rhIL-8. 3. Pretreatment with L-NAME significantly enhanced the TNF-alpha (10(3) u)-induced neutrophil recruitment and human IL-8 equivalents production at 6 h, but not at 1 h of TNF-alpha administration (early phase). L-Arginine reversed the responses to L-NAME. Pretreatment with 0.2% DMSO (i.v.) significantly inhibited TNF-alpha-induced neutrophil recruitment and human IL-8 equivalents release both in the early and late phase of the responses. Pretreatment with DMSO also inhibited the enhancement effect of L-NAME on the late phase of TNF-alpha-induced responses. DMSO failed to modify exogenous rhIL-8-induced neutrophil recruitment. Neither L-NAME nor DMSO alone induced any significant change in neutrophil numbers or human IL-8 equivalent level in BAL fluid. 4. Neutrophil depletion by cyclophosphamide pretreatment failed to modify TNF-alpha-induced human IL-8 equivalent release. 5. The expression of beta 2-integrin, CD11b/CD18 on neutrophils was increased only in the late but not early phase of TNF-alpha stimulation. L-NAME failed to modify these responses. 6. In conclusion, we demonstrated that NO may be an important endogenous inhibitor of TNF-alpha-induced leukocyte chemotaxis via inhibition of IL-8 production. Thus, the production of NO in airway inflammatory diseases may play a negative feedback role in self-limiting the magnitude of inflammatory responses.     

Electron capture in Iq+ (q = 10–41) + He collisions at low energies

One electron capture processes in I^q+ (q = 10–41) +He collisions at low energies have been investigated. It is found that total cross sections for one-electron capture processes increase roughly linearly with increasing charge q of the incident ions and also increase with the square of the crossing radius R_c of the diabatic potential energy curves where the electron transfer takes place. These smooth increases are in contrast to those observed for ions with low charge q < 10.