Heavy oxynitridation technology for forming highly reliable flash-type EEPROM tunnel oxide films

For the first time, it is demonstrated that in flash-type EEPROMs, the endurance properties are dramatically improved by heavy oxynitridation (RTONO) of the tunnel oxide. The layer composition evaluated by SIMS measurement indicates that large amounts of N atoms (>10/sup 20/ atom/cm/sup 3/) pile up at the SiO/sub 2/-Si interface, and are distributed in the bulk SiO/sub 2/. In addition, the RTONO film reduces the number of hydrogen atoms, which are the origin of electron traps. This oxynitridation causes a decrease of both electron and hole traps in the tunnel oxide, resulting in an improvement of the threshold voltage narrowing.<>     

Assessment and treatment of liver disease in Japanese haemophilia patients

OBJECTIVES: To examine the efficacy of various parameters obtained by transrectal ultrasonography (TRUS) as predictors of the onset of acute urinary retention in patients with benign prostatic hyperplasia (BPH). METHODS: From April 1993 to March 1997, 331 men aged 51 to 84 years with symptoms of BPH were enrolled in this study. Among them, 64 patients presented to our clinic because of acute urinary retention. TRUS was used to calculate the transition zone (TZ) volume, the transition zone index (TZ index = TZ volume/total prostate volume), the total prostate volume, and presumed circle area ratio (PCAR). To compare the usefulness of the various indices, the area under the receiver-operator characteristic (ROC) curve was calculated for each index. RESULTS: There were significant differences in the American Urological Association (AUA) symptom score, total prostate volume, TZ volume, TZ index, and PCAR between patients with and without acute urinary retention, but no significant differences in age and quality of life score. In patients with acute urinary retention, the area under the ROC curve was 0.924 for the TZ index, 0.834 for the TZ volume, 0.753 for the PCAR, 0.684 for the total prostate volume, and 0.628 for the AUA symptom score. CONCLUSIONS: The TZ index is an accurate predictor of acute urinary retention in patients with BPH and may be a useful method for deciding between surgical intervention and antiandrogen treatment.     

Syntheses and antitumor activity of cis-restricted combretastatins: 5-membered heterocyclic analogues

A series of cis-restricted combretastatin analogues with 5-membered heterocycles were synthesized and their inhibitory activity against microtubule assembly and cytotoxic activity against the colon 26 adenocarcinoma cancer cell line were evaluated. Some of the heterocyclic analogues showed potent antitubulin activity and cytotoxicity. Compounds 16 and 35 showed marked tumor growth suppression in the colon 26 murine tumor model.     

Distribution and subcellular localization of a growth inhibitory factor in hamster liver and its intracellular partner(s)

The subcellular, intralobular distributions and intracellular partner(s) of a factor which inhibits the proliferation of cell growth (Hashimoto C. et al. (1994) Biochim. Biophys. Acta 1221, 107-117) were determined in hamster livers, using a combination of immunological and biochemical techniques. The IgG fraction from an antiserum raised against the growth inhibitory factor with 37 kDa was shown to be highly specific for the antigen. The nuclear and cytosolic fractions demonstrated inhibitory effects on cell growth and Western blot analysis revealed that both fractions contained the immunoreactive 37 kDa protein with the anti-inhibitory factor IgG but microsomal and mitochondrial fractions did not. The nuclear and cytoplasmic localization of the inhibitory factor were further confirmed by immunochemical staining mediated through the immune IgG and an avidin-biotinylated horseradish peroxidase complex, the parenchymal liver cells were clearly stained, but endothelial and connective tissue cells were not. Although some staining was evident throughout the liver parenchyma, the hepatocytes with most intensively stained nuclei were located in the periportal region. In the liver from hamsters 6 days old or the regenerating hamster livers 3 days after partial hepatectomy, the staining intensity was low and the number of hepatocytes with the inhibitory factor positive nuclei was very few compared with the adult hamster livers. In primary cultures of the isolated hepatocytes from adult hamster the inhibitory factor disappeared from nuclei after incubation for 24-48 h. The extracts of hepatic nuclei from adult hamsters were immunoprecipitated with either the anti-growth inhibitory factor IgG or a monoclonal antibody to the RM protein. The growth inhibitory factor and the RB protein coprecipitated in each case, implying that the proteins were complexed with each other in the nuclei. The RB protein family is composed of two sets of species, an un- or underphosphorylated species and a hyperphosphorylated one. It was suggested that the factor bound preferentially to the un- or underphosphorylated member of the family.     

Inhibitory activities of gatifloxacin (AM-1155), a newly developed fluoroquinolone, against bacterial and mammalian type II topoisomerases

We determined the inhibitory activities of gatifloxacin against Staphylococcus aureus topoisomerase IV, Escherichia coli DNA gyrase, and HeLa cell topoisomerase II and compared them with those of several quinolones. The inhibitory activities of quinolones against these type II topoisomerases significantly correlated with their antibacterial activities or cytotoxicities (correlation coefficient [r] = 0.926 for S. aureus, r = 0.972 for E. coli, and r = 0.648 for HeLa cells). Gatifloxacin possessed potent inhibitory activities against bacterial type II topoisomerases (50% inhibitory concentration [IC50] = 13.8 microg/ml for S. aureus topoisomerase IV; IC50 = 0.109 microg/ml for E. coli DNA gyrase) but the lowest activity against HeLa cell topoisomerase II (IC50 = 265 microg/ml) among the quinolones tested. There was also a significant correlation between the inhibitory activities of quinolones against S. aureus topoisomerase IV and those against E. coli DNA gyrase (r = 0.969). However, the inhibitory activity against HeLa cell topoisomerase II did not correlate with that against either bacterial enzyme. The IC50 of gatifloxacin for HeLa cell topoisomerase II was 19 and was more than 2,400 times higher than that for S. aureus topoisomerase IV and that for E. coli DNA gyrase. These ratios were higher than those for other quinolones, indicating that gatifloxacin possesses a higher selectivity for bacterial type II topoisomerases.     

Effects of short duration morning bright light in healthy elderly. II: sleep and motor activity

Subjective sleep feelings and motor activity were measured in seven healthy elderly subjects for 6 days. The subjects were exposed to bright light (6000 lux) for 30 min in the morning or instructed to sit in front of a desktop lighting device without light. The average level of motor activity during the night was significantly decreased in the bright light condition, compared with the controlled condition. However, daytime motor activity did not show significant differences between the two conditions. From these findings, even a short duration of morning bright light is effective in maintaining sleep without changing daytime activity.     

An ergonomic evaluation of lens accommodation related to visual circumstances

This study is intended to make clear the relationships between a number of external conditions (target luminance, size, etc.), dynamic responsiveness of the lens accommodation, and microfluctuation. Further, the effects of ageing and the difference between monocular and binocular observations are examined. These studies established that age factors have a large bearing on the ability of the lens to focus on an object, as well as affecting such abilities as the responsiveness of the lens accommodation, amplitude of lens accommodation response, microfluctuation, and contraction and relaxation time. Of these accommodation functions, such factors as contraction and relaxation time clearly reflect the ease of seeing an object. Clear relationships between the amount of diopter and the ease of seeing an object were also observed. Further, it was established that a binocular observation is more responsive (velocity of contraction) than a monocular one. As to the microfluctuation, on the other hand, clear effects of age on its spectrum distribution were recognized but no definite correlations concerning the ease of seeing an object were observed.     

Destructive constructions of nanostructures with carbon nanotubes through nanorobotic manipulation

Nanostructures are constructed with destructively fabricated nano building blocks based on multiwalled carbon nanotubes through three-dimensional nanorobotic manipulation in free space. In situ mechanical property characterization is applied for the selection of a nanotube with desired elasticity. Destructive fabrication is demonstrated as an effective way to obtain layered and/or sharpened structures of nanotubes for the applications as nanobearings and probe tips, linear nanobearing motion has been observed, and a method is shown by using surface clamping van der Waals forces for the better control of the geometries of the nanotubes with destructive fabrication. The prepared building blocks are positioned together with nanorobotic manipulators under real-time observation with a field-emission scanning electron microscope, and are constructed through electron-beam-induced deposition.     

Infection with hepatitis G virus and its strain variant, the GB agent (GBV-C), among blood donors in Japan

Much of the morbidity and mortality seen in cystic fibrosis (CF) is related to chronic infection of the respiratory tract with Pseudomonas aeruginosa. Some studies have attributed the strong relationship between CF and Pseudomonas colonization to the presence of increased numbers of specific cell-surface receptors, although other work suggests that this relates to the presence of mucus. Several groups are now assessing the use of gene transfer as a novel form of treatment for CF. We have examined whether P. aeruginosa binding to freshly obtained CF respiratory epithelial cells is increased, and have studied the effects of transfer of the CF transmembrane conductance regulator (CFTR) gene on this attachment. Binding of P. aeruginosa to noncultured nasal epithelial cells from both CF patients (n = 31) and healthy controls (n = 15) was studied with scanning electron microscopy. Binding was also assessed for CF cells following transfection with CFTR/liposome complexes. Epifluorescence microscopy was used to assess the effects of gene transfer on chloride fluxes. Adherence of P. aeruginosa directly to the cell surface of CF airway epithelium was significantly (P < 0.001) increased over that in non-CF controls. Liposome-mediated CFTR gene transfer resulted in a significant (P < 0.01) reduction in the numbers of bacteria bound to ciliated epithelial cells. Fluorescence microscopy confirmed correction of the basic chloride defect. Thus, in CF, the absence of normal CFTR results in increased binding of P. aeruginosa to respiratory epithelial cells. This abnormality can be corrected in vitro by restoration of CFTR function. This has important implications both for the pathogenesis of CF and for the future application and assessment of gene therapy for this disease.