Epstein-Barr virus promotes epithelial cell growth in the absence of EBNA2 and LMP1 expression

We attempted to infect primary gastric epithelia (PGE) with recombinant Epstein-Barr virus (EBV) carrying a selectable marker that made it possible to select EBV-infected cells. Cells dually positive for EBV-determined nuclear antigen (EBNA) and cytokeratin were detected in 3 of 21 primary cultures after 3 days of EBV inoculation. From one culture, EBV-infected cell clones were repeatedly obtained at a frequency of 3 to 5 cell clones per 10(6) cells. EBV-infected clones had enhanced population doubling and grew to attain a highly increased saturation density, together with acquisition of marked anchorage independence. The infected clones retained the ultrastructural morphology characteristic of gastric mucosal epithelium and have been growing stably for more than 18 months (corresponding to at least 300 generations) so far, in clear contrast to the parental PGE cells, which ceased growth after 60 generations. The p53 gene of the parental PGE cells was found to be overexpressed, perhaps thereby conferring the basal potential for long-term survival in vitro. Moreover, EBV infection accelerated, to a significant extent, the growth rate and agar clonability of NU-GC-3 cells, an established EBV-negative but EBV-susceptible human gastric carcinoma cell line. Both EBV-converted PGE and NU-GC-3 clones, like EBV-positive gastric carcinoma biopsy specimens, expressed a restricted set of EBV latent infection genes characterized by the absence of EBNA2 and latent membrane protein 1 (LMP1) expression. These results indicate that EBV infection causes a transformed phenotype on PGE in the setting of possible unregulated cell cycling and renders even established gastric carcinoma cells more malignant via a limited spectrum of viral latent-gene expression. This study may reflect an in vivo scenario illustrating multiphasic involvement of EBV in carcinogenesis of gastric or other epithelial cancers.     

On the iterative decoding of multilevel codes

Iterative decoding of multilevel coded modulation is discussed. Despite its asymptotic optimality with proper design, the error correcting capability of multilevel codes may not be fully exploited for finite block length with conventional multistage decoding. This fact stems from the suboptimality of multistage decoding giving rise to increased error multiplicity at lower index stages and the associated error propagation to higher stages. Such problems can be overcome in many situations by introducing iterative decoding which often significantly compensates the suboptimality of a staged decoder. The class of multilevel codes achieving practically important bit-error performance near the Shannon limit becomes far wider with iterative decoding     

Superplasticity in an Aluminum Alloy 6061/A12O3p Composite

［1］T.G.Nieh, C.A.Henshall and J.Wadsworth: Scr. Metall., 1985, 18, 1405. ［2］K.Higashi, T.Okada, T.Mukai, S.Tanimura, T.G.Nieh and J.Wadsworth: Scr. Metall. Mater., 1992, 26, 185. ［3］X.Huang, Q.Liu, C.K.Yao and M.Yao: J. Mater. Sci.Lett., 1991, 10, 964. ［4］T.Imai, M.Mabuchi, Y.Tozawa and M.Yamada: J.Mater. Sci. Lett., 1990, 9, 255. ［5］M.Mabuchi, K.Higashi, S.Wada and S.Tanimura: Scr.Metall. Mater., 1992, 26, 1269. ［6］M.Mabuchi, K.Higashi, K.Inoue and S.Tanimura: Scr.Metall. Mater., 1992, 26, 1839. ［7］M.Mabuchi, K.Higashi, Y.Okada, S.Tanimura, T.Imai and K.Kubo: Scr. MetalJ. Mater., 1991, 25, 2517. ［8］B.Q.Han and K.C.Chan: Scr. Mater., 1997, 36, 593. ［9］M.Mabuchi, K.Higashi and T.G.Langdon: Acta Metall. Mater., 1994, 42, 1739. ［10］T.Imai, G.L‘Esperance and B.D.Hong: Scr. Metall.Mater., 1994, 31, 321. ［11］M.Mabuchi and K.Higashi: Phil Mag. A, 1996, A74,887. ［12］G.Nieh and J.Wadsworth: Mater. Sci. Eng. A, 1991,A147, 129. ［13］T.Imai, S.Kojima, G.L‘Esperance, B.Hong and D.Jiang: Scr. Mater., 1996; 35(10), 1199. ［14］O.A.Kaibyshev, V.Kazyhanov and C.C.Bampton:Key. Eng. Mater., 1997, 127-131, 953. ［15］K.Matsuki, M.Tokizawa and S.Murakami: Mater. Sci.Forum, 1997, 243-245, 309. ［16］S.Mishra, T.R. Bieler and A.K.Mukherjee:Acta Mater., 1997, 45, 561. ［17］A.H. Chokshi, T.R.Rieler, T.G.Nieh, J.Wadsworth and A.K.Mukherjee: Superplasticity in Aerospace eds.H.C.Heikkenen and T.R.McNelley, The Metallurgical Society, Warrendale, PA, 1988, 229. ［18］M.Mabuchi and K.Higashi: Scr. Metall., 1996, 34(12),1893     

HIGH STRAIN RATE SUPERPLASTICITY OF DISCONTINUOUS CERAMIC FIBER REINFORCED ALUMINUM COMPOSITES

1.IntroductionHighstrainratesuperplasticity(HSRS)inceramicwhiskerorparticulatereinforcedaluminumalloycompositesisexpectedtoofferanefficientlynearannetshapeformingtech-niquetoautomobile,aerospace,andevensemi--conductorindustries,sincetheHSRScom-positesusuallyexhibitatotalelongationof250--600%atahighstrainrateofabout0.1--10s~1[1-ill.ItisthoughtthatprimarydeformationmechanismoftheHSRSisgrainboundaryslidingsincethecompositeshavethefinegrainsizeof3--0.8pm.TheHSRSofthecompositesusuallymanifest…     

Formation of IPN organic-inorganic polymer hybrids utilizing the photodimerization of thymine

Summary Formation of an interpenetrating polymer network (IPN) composed of organic polymer gel and silica gel in the form of polymer hybrids was conducted by utilizing the photodimerization of thymine bases. Thymine-modified poly(2-methyl-2-oxazoline) (POZO-T) was synthesized by the condensation reaction of partially hydrolyzed polyoxazoline and 1-(2-carboxyethyl)thymine. Organic-inorganic polymer hybrids were prepared from POZO-T and tetramethoxysilane (TMOS). Transparent and homogeneous polymer hybrids could be obtained. The photodimerization and the reverse reaction of thymine in the polymer hybrids were monitored by the UV absorption spectroscopy. Received: 27 March 2000/Revised version: 5 June 2000/Accepted: 15 June 2000     

Effect of high doses of synthetic estrogen on lipid metabolism in castrated male rats

The mechanism by which high doses of estrogen influences lipid metabolism was studied with a microtubular blocking agent. Castrated male rats received oral injection daily for 14 days of 3 mg hexestrol in olive oil, or oil alone as controls. About half of the animals in each group were injected intraperitoneally with 4 mg/100 g body weight colchicine 3 hr before they were killed. Hexestrol treatment caused an accumulation of esterified cholesterol in the liver while it decreased those in serum. Triglyceride concentrations slightly decreased in the liver but were unaffected in serum. On polyacrylamide-gel disc electrophoresis, the peaks of high density lipoproteins (HDL) and low density lipoproteins (LDL) were decreased remarkably. Electron microsopic examination of hepatocytes revealed electron-lucent lipid droplets in the cytoplasm. After a colchicine treatment of the control animals, concentrations of esterified cholesterol and triglycerides markedly increased in the liver, while those in serum decreased. Electron microscopic examination of hepatocytes revealed numerous secretory vesicles filled with nascent VLDL. In hexestrol-treated animals, the colchicine treatment was associated with marked decreases in serumesterified cholesterol and triglyceride as seen in the controls. However, there were no further increases of esterified cholesterol in the liver, and the increase of triglycerides was slight. Electron microscopic examination showed less secretory droplets than in the controls. These data suggest that very low density lipoproteins (VLDL) synthesis in the liver of hexestrol treated rats was inhibited. An accumulation of esterified cholesterol with a marked decrease in serum could not be accounted for by the inhibition of lipoproteins secretion, but rather by their enhanced entry into the liver.     

Application of human thermal load into unsteady condition for improvement of outdoor thermal comfort

Human thermal comfort is studied as a countermeasure to the thermal stress in outdoor urban space. Outdoors, people experience the strong impact of solar radiation in states that are unsteady and non-uniform. The feeling of comfort is a mixed sensation that can be easier to improve overall, as compared with a global large-scale effort, and can lead to improved ways of saving energy and reducing costs. Moreover, this can be directly beneficial to human experience and fulfill natural human desires. Since a thermal comfort index is a useful tool for understanding the present state and evaluating the impact of countermeasures, we examine the effects of the human thermal load, which is a thermal comfort index based on the energy balance of the human body. In a steady state, and even in an unsteady state with its variations in weather and human factors, thermal comfort values can generally be obtained by using the overall human thermal load. The reason for this is that the human thermal load takes physiological factors in account as well as weather parameters. This leads to the idea that thermal sensations follow from the human thermal load, which can then well describe a given human environment. As a result, human sensations as expressed by the human thermal load pave the way to the creation of comfortable urban spaces that require minimum expense and energy as an example of simple heat transport model focusing on urban outer structure.     

Development of an LC–MS/MS Method for the Analysis of Free Sphingoid Bases Using 4-Fluoro-7-nitrobenzofurazan (NBD-F)

The molecular species of sphingoid bases were tagged with the fluorescent amino group reagent, 4-fluoro-7-nitrobenzofurazan (NBD-F). The NBD-sphingoid bases were analyzed by a highly selective and sensitive liquid chromatography–electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS) technique capable of reliable detection of several fmol of the derivatives. Lipid extracts from plant samples were derivatized with NBD-F, and all nine species of free sphingoid bases present in plant sphingolipids were separated and quantified for the first time; a complete baseline resolution was achieved for cis-8 and trans-8 isomers of sphingoid bases by reversed phase HPLC on a C₁₈ column. The extraction and derivatization procedures and LC–MS/MS method can facilitate the progress of the studies for seeking the active components of sphingoid bases species in response to biological challenges.     

Highly Manufacturable and Reliable HfSiON N-FET With Poly-Si/a-Si Stacked Gate for LSTP Applications

We have proposed a novel poly-Si/a-Si/HfSiON transistor to enhance reliabilities without performance degradation for a 65-nm-node low standby power (LSTP) application. By insertion of a thin amorphous-Si layer between the Poly-Si gate electrode and HfSiON, both phosphorus penetration from gate electrode and a reaction at gate electrode/HfSiON interface are successfully suppressed, so that positive bias temperature instability, one of the biggest issues for high-k gate dielectric, is drastically improved by two orders of magnitude. By carefully optimizing the gate stack structure of HfSiON, the HfSiON device can satisfy both lower gate leakage and gate-induced drain leakage at the same time. As a result, an excellent I_on- I_standby (= I_g + l_off) characteristic can be achieved, compared to the conventional SiON device. The a-Si insertion technique can realize the combination between the high-k gate dielectric and Poly-Si for future LSTP applications.     

Development of a TOF measurement system of charge carrier dynamics in diamond thin films using a UV pulsed laser

A fast TOF measurement system with 150 ps time resolution for transport behavior of free charge carriers in an intrinsic diamond film by using a UV pulsed laser was developed. The 213 nm UV laser light narrowed to approximately 80 μm widths could locally create hole–electron pairs in selected locations on a diamond film between two parallel electrodes on the surface. This system measured accurate charge transport characteristics in a diamond film, because created charge carriers moved in a part of the diamond film where they did not get any influence from the laser irradiation. Diamond samples used for verification of the TOF system were intrinsic CVD diamond films with thickness between 4 and 10 μm grown on HP/HT diamond substrates. Transit time of holes for one diamond film was 4.7 ns with a traverse distance of 250 μm. The local irradiation of laser made it possible to measure transport characteristics of electrons and holes separately. In addition, it substantially reduced the influence of photoelectron, because the laser beam did not irradiate electrodes. Through several examinations, excellent reliability of the TOF system was confirmed.