Mutagenicity and DNA-damaging activity of decomposed products of food colours under UV irradiation

Five synthetic food colours Food Red Nos 3, 40 and 102 and Food Blue Nos 1 and 2, and their UV irradiated products were tested for mutagenic activity by means of the Ames test using Salmonella typhimurium strains TA98 and TA100. Food colours were irradiated with UV light for 14 days. Food Red Nos 3, 40 and 102 and Food Blue No. 1 were non-mutagenic before and after irradiation. UV irradiated products of Food Blue No. 2 were mutagenic in TA98 with or without S-9 mix. The mutagenic activity increased with increasing irradiation period, reached maximum potency on day 6, and then decreased. Moreover, Food Blue No. 2 showed DNA-damaging activity after 14 days of irradiation in rec-assay using Bacillus subtilis strains H17 and M45. The capillary electrophoresis was applied for the analysis of UV irradiated products of Food Blue No. 2. The original peak of Food Blue No. 2 was decomposed into seven peaks after UV irradiation.     

Mechanisms responsible for resistance of sublines derived from leukemia cell lines to an antitumor agent 9-beta-D-arabinofuranosyl-2-fluoroadenine

An agent 9-beta-D-arabinofuranosyl-2-fluoroadenine (2-F-Ara-A) is a main metabolite of fludarabine, a fluorinated purine analogue with antitumor activity in lymphoproliferative malignancies. In this study, the mechanism responsible for the resistance of cancer cells to fludarabine was examined using the 2-F-Ara-A-resistant sublines JOK-1/F-Ara-A and L1210/F-Ara-A from a human hairy leukemic cell line (JOK-1) and a mouse leukemic cell line (L1210) respectively, which were established by continuous treatment of the parental cell lines with 2-F-AraA. JOK-1/F-Ara-A and L1210/F-Ara-A cells were more than 55 and 29 times more resistant to 2-F-Ara-A than were their parent cell lines, and showed a high cross-resistance to 1-beta-D-arabinofuranosylcytosine but not to doxorubicin or vincristine. These resistant sublines intracellularly accumulated almost the same amount of 2-F-Ara-A as did their parent cell lines. However, the amount of 2-F-Ara-ATP, a cytotoxic metabolite of 2-F-Ara-A, decreased by 2.6% (JOK-1/F-Ara-A C3), 6% (L1210/F-Ara-A C1) and 3.7% (L1210/F-Ara-A C7) relative to the levels in the parent cell lines. Enzymatically, these resistant cells hardly activated deoxycytidine (dCyd) and 2-F-Ara-A. In addition, the abilities to phosphorylate deoxyadenosine and deoxyguanosine were also decreased in the resistant cells in comparison with the parent cells. These findings suggest that the deficiency in activity of dCyd kinase may contribute to the resistance of 2-F-Ara-A.     

Some characteristics of a cellular receptor for virulent infectious bursal disease virus by using flow cytometry

A flow cytometric virus binding assay that directly visualizes the binding of infectious bursal disease virus (IBDV) to its target cells was established. The chicken B lymphoblastoid cell line, LSCC-BK3, which is permissive for IBDV infection, bound high levels of the virus. Another B lymphoblastoid cell line, LSCC-1104-B1, bound low levels of the virus, although it was nonpermissive. No virus binding was detected in nonpermissive T lymphoblastoid cell lines. In the binding assay to heterogeneous cell populations of chicken lymphocytes, IBDV (a highly virulent OKYM strain) bound to 94% cells in the lymphocytes prepared from the bursa of Fabricius, 37% cells in those prepared from the spleen, 3% cells in those prepared from the thymus, and 21% cells in those prepared from the blood. Most of the cells, which bound the virus, were surface immunoglobulin M (SIgM)-positive, but a small number of them were SIgM-negative. Additionally, the binding of IBDV to the LSCC-BK3 cells was affected by treatment of the cells with proteases and N-glycosylation inhibitors. These findings may indicate that the IBDV host range is mainly controlled by the presence of a virus receptor composed of N-glycosylated protein associated with the subtle differentiation stage of B-lymphocytes represented mostly by SIgM-bearing cells.     

Process and device characterization for a 30-GHz fT submicrometer double poly-Si bipolar technology using BF2-implanted base with rapid thermal process

Process and device parameters are characterized in detail for a 30-GHz f_T submicrometer double poly-Si bipolar technology using a BF₂-implanted base with a rapid thermal annealing (RTA) process. Temperature ramping during the emitter poly-Si film deposition process minimizes interfacial oxide film growth. An emitter RTA process at 1050°C for 30 s is required to achieve an acceptable emitter-base junction leakage current with an emitter resistance of 6.7×10^-7 Ω-cm², while achieving an emitter junction depth of 50 nm with a base width of 82 nm. The primary transistor parameters and the tradeoffs between cutoff frequency and collector-to-emitter breakdown voltage are characterized as functions of base implant dose, pedestal collector implant dose, link-base implant dose, and epitaxial-layer thickness. Transistor geometry dependences of device characteristics are also studied. Based on the characterization results for poly-Si resistors, boron-doped p-type poly-Si resistors show significantly better performance in temperature coefficient and linearity than arsenic-doped n-type poly-Si resistors     

Preparation of TiB2 sintered compacts by hot pressing

A sintered compact of titanium diboride (TiB₂) was prepared by hot pressing of the synthesized TiB₂ powder, which was obtained by a solid-state reaction between TiN and amorphous boron. Densification of the sintered compact occurred at 20 MPa and 1800° C for 5 to 60 min with the aid of a reaction sintering, including the TiB₂ formation reaction between excess 20 at % amorphous boron in the as-synthesized powder (TiB₂ + 0.2B) and intentionally added 10 at % titanium metal. A homogeneous sintered compact of a single phase of TiB₂, which was prepared by hot pressing for 30 min from the starting powder composition [(TiB₂ + 0.2B) + 0.1 Ti], had a fine-grained microstructure composed of TiB₂ grains with diameters of 2 to 3 m. The bulk density was 4.47 g cm^–3, i.e. 98% of the theoretical density. The microhardness, transverse rupture strength and fracture toughness of the TiB₂ sintered compact were 2850 kg mm^–2, 48 kg mm^–2 and 2.4 MN m^–3/2, respectively. The thermal expansion coefficient increased with increasing temperature up to 400° C and had a constant value of 8.8 x 10^–6 deg^–1 above 500° C.     

Effects of computers on Japanese schools

In this paper I consider how the computer can or should be accepted in Japanese schools. The concept of teaching in Japan stresses learning from a long-term perspective. Whereas in the instructional technology, on which the CAI or the Tutoring System depends, step-by-step attainments in relatively short time are emphasized. The former is reluctant in using the computer, but both share the Platonic perspective which are goal-oriented. However, The Socratic teacher, who intends to activate students' innate disposition to be better, would find another way of teaching and use of the computer.     

Effect of grain size on creep of Ti-53.4mol%Al intermetallics at 1100 K

Constant stress creep under compression stress, 100 to 316 MPa, at 1100 K was investigated on single-phase TiAl intermetallics. The material was ingot-cast, isothermally forged, and then annealed to produce stable equi-axed grain structures, whose average grain diameters were 25, 42 and 70m. Creep curves were very similar among the three specimens with different grain diameters and the creep rates at a given strain, as well as the minimum creep rates, depended little on grain size. Two regimes were observed on the stress dependence of the minimum creep rate. The stress exponent under high stresses was about 4.5, independent of grain size. Under stresses lower than about 150 MPa it became about 8.     

Development of a dual‐lamp projector with higher brightness

Stationary projectors mainly used in system applications have recently gained a wider application range, including general presentations in halls and large conference rooms and being used, for example, in digital signage and for monitoring purposes. Consequently, they are required to meet new market demands for durability, reliability, and flexibility in installation in addition to their conventional basic performance such as especially high brightness. To achieve especially high brightness, a new optical system with two lamps is proposed; the profile of the cover glass that prevents the glass from scattering is made aspherical, the profile of the beam‐combining mirror is improved with its position optimized, and the size of the incident plane of the integrator rod is made larger (1.1 times). These measures resulted in an optical system of an even higher efficiency with 7000 lm, which is the highest in its class (according to a June 2010 investigation). Also, the arrangement of two parallel lamps completely eliminated the effect of heat passing from one lamp to the other, which helped secure durability, reliability, and flexibility in installation. Furthermore, the combined use of the unique non‐telecentric optical system, adopted from the conventional single‐lamp model, helps maintain the class‐highest contrast ratio.^1,2     

Highly reliable a‐IGZO TFTs on a plastic substrate for flexible AMOLED displays

We have successfully reduced threshold voltage shifts of amorphous In–Ga–Zn–O thin‐film transistors (a‐IGZO TFTs) on transparent polyimide films against bias‐temperature stress below 100 mV, which is equivalent to those on glass substrates. This high reliability was achieved by dense IGZO thin films and annealing temperature below 300 °C. We have reduced bulk defects of IGZO thin films and interface defects between gate insulator and IGZO thin film by optimizing deposition conditions of IGZO thin films and annealing conditions. Furthermore, a 3.0‐in. flexible active‐matrix organic light‐emitting diode was demonstrated with the highly reliable a‐IGZO TFT backplane on polyimide film. The polyimide film coating process is compatible with mass‐production lines. We believe that flexible organic light‐emitting diode displays can be mass produced using a‐IGZO TFT backplane on polyimide films.     

GBLT-VG for High User Densities by User Group Behavior and Hot Point in MMO Virtual Environment

Massively Multiplayer Online (MMO) games have large-scale virtual environments. Here, we propose a load distribution technique called the Group Based Load-distribution Technique with Virtual Group (GBLT-VG) that utilizes Peer-to-Peer (P2P) communication to maintain scalability under high user density conditions in MMO virtual environments. A common problem of P2P virtual environments is that user group behavior frequently generates high user density conditions. Existing techniques to manage the virtual environment cannot maintain performance in such high user density situations. The proposed technique, GBLT-VG, reduces area management loads of manager peers by introducing a new manager who manages a user neighbor group. GBLT-VG forms the user neighbor group efficiently by using party function under high user density conditions caused by users?? cooperative behaviors. In addition, GBLT-VG reduce the management load by using a virtual group when a number of parties is small, thereby decreasing the existing managers?? loads dynamically. This paper also presents simulation results demonstrating how GBLT-VG can reduce the average number of users managed by the server.