Spatial and temporal sensitivity degradation of primary visual cortical cells in senescent rhesus monkeys

Human visual function declines with age. Much of this decline is mediated by changes in the central visual pathways. In this study we compared the spatial and temporal sensitivities of striate cortical cells in young and old paralysed macaque monkeys. Ext

Circulating immunoglobulin A- and immunoglobulin G-secreting hybridoma cells in peripheral blood preferably migrate to female genital tracts. The role of sex hormones

Antigen-specific circulating immunoglobulin-secreting cells (ISC) migrate to various secondary and tertiary lymphoid tissues. To understand the migration of the cells into the genital tract and its regulation by sex hormones, spleen-derived SG2 hybridoma cells secreting immunoglobulin G2b (IgG2b) and Peyer's patch-derived PA4 hybridoma cells secreting polymer IgA were labelled with (3) H-TdR, and intravenously injected into syngeneic mice of both sexes. Using flow cytometry, surface molecular markers of plasma cells, CD38 and CD138, and adhesion molecules, CD49d, CD162, and CD11a were found to be positive in SG2 and PA4 cells, but CD62L, alpha4beta7 and CD44 were not expressed on these cells. The relative distribution indexes (RDIs) of the cells in genital tract and other tissues were measured. The means of RDIs of SG2 and PA4 cells in female genital tissues were 6.5 and 4.5 times as many as the means in male genital tissues, respectively. The treatment of ovariectomized mice with beta-oestradiol significantly increased the RDIs of PA4 cells in cervix and vagina, but decreased the RDIs of SG2 cells in vagina, horn of uterus, uterus and rectum (P <0.05). Progesterone treatment increased the RDIs of PA4 cells in vagina and rectum (P <0.05). The treatment with testosterone significantly increased the RDIs of SG2 and PA4 cells in epididymis and accessory sex glands (P <0.05). These results demonstrate that the female genital tract is the preferable site for the migration of circulating hybridoma cells to the male genital tract, and sex hormones play an important role in regulation of the migration of circulating ISC to genital tracts.

Antioxidant enzyme activities of Microcystis aeruginosa in response to nonylphenols and degradation of nonylphenols by M-aeruginosa

The aim of this study was to examine the effects of chemical nonylphenols (NPs) on the antioxidant system of Microcystis aeruginosa strains. The degradation and sorption of NPs by M. aeruginosa were also evaluated. High concentrations of NPs (1 and 2 mg/l) were found to cause increases in superoxidase dismutase (SOD) and glutathione-S-transferase (GST) activities and in glutathione (GSH) levels. These results suggest that toxic stress manifested by elevated SOD and GST levels and GSH contents may be responsible for the toxicity of NPs to M. aeruginosa and that the algal cells could improve their antioxidant and detoxification ability through the enhancement of enzymatic and nonenzymatic prevention substances. The observed elevations in GSH levels and GST activities were relatively higher than those in SOD activities, indicating that GSH and GST contributed more in eliminating toxic effects than SOD. Low concentrations of NPs (0.05-0.2 mg/l) enhanced cell growth and decreased GST activity in algal cells of M. aeruginosa, suggesting that NPs may have acted as a protecting factor, such as an antioxidant. The larger portion of the NPs (> 60%) disappeared after 12 days of incubation, indicating the strong ability of M. aeruginosa to degrade the moderate persistent NP compounds. The sorption ratio of M. aeruginosa after a 12-day exposure to low nominal concentrations of NPs (0.02-0.5 mg/l) was relatively high (> 30%). The fact that M. aeruginosa effectively resisted the toxic effects of NPs and strongly degraded these pollutants indicate that M. aeruginosa cells have a strong ability to adapt to variations in environmental conditions and that low and moderate concentrations of organic compounds may favor its survival. Further studies are needed to provide detailed information on the fate of persistent organic pollutants and the survival of algae and to determine the possible role of organic pollutants in the occurrence of water blooms in eutrophic lakes.

Effects of salinity on food intake, growth, and survival of pufferfish (Fugu obscurus)

The food intake, growth, food conversion ratio and survival of yearling pufferfish, Fugu obscurus Abe, were investigated under different water salinity conditions over a 54-day period. Within the salinity regimes of 0 (freshwater), 8, 18, and 35parts per thousand, the food intake levels were 0.97%, 1.43%, 1.19% and 1.01%, respectively; food conversion ratios were 1.31, 1.93, 1.61 and 1.36, respectively; and specific growth rates were 0.41%, 1.15%, 0.84%, and 0.35%, respectively. The three data series were reduced with increasing salinity. However, the survival rates did not show the same tendencies, which were 80%, 100%, 100%, and 67%, respectively. There were significant differences among the treatments. In conclusion, the yearling pufferfish optimum culture salinity condition was about 8parts per thousand.

Characterization of polymorphous silicon thin film and solar cells

Polymorphous silicon (pm-Si:H) films have been prepared by a new regime of plasma enhanced chemical vapour deposition in the region adjacent of phase transition from amorphous to microcrystalline state. Comparing to the conventional amorphous silicon (a-Si:H), the pm-Si:H has higher photoconductivity (sigma(ph)), better stability, and a broader light spectral response range in the longer wavelength range. It can be found from Raman spectra that there is a notable improvement in the medium range order. There are a blue shift for the stretching mode of IR spectra and a red shift for the wagging mode. The shifts are attributed to the variation of the microstructure. By using pm-Si:H film as intrinsic layer, a p-i-n junction solar cell was prepared with the initial efficiency of 8.51% and a stabilized efficiency of 8.01% (AM1.5, 100mw/cm(2)) at room temperature (T-R).

Growth of GaSb and GaInAsSb layers for thermophotovolatic cells by liquid phase epitaxy - art. no. 68411E

GaSb based cells as receivers in thermophotovoltaic system have attracted great interest and been extensively studied in the recent 15 years. Although nowadays the manufacturing technologies have made a great progress, there are still some details need to make a further study. In this paper, undoped and doped GaSb layers were grown on n-GaSb (100) substrates from both Ga-rich and Sb-rich solutions using liquid phase epitaxy (LPE) technique. The nominal segregation coefficients k of intentional doped Zn were 1.4 and 8.8 determined from the two kinds of GaSb epitaxial layers. Additionally, compared with growing from Ga-rich solutions, the growing processes from Sb-rich solutions were much easier to control and the surface morphologies of epitaxial layers were smoother. Further-more, in order to broaden the absorbing edge, Ga1-xInxAsySb1-y quaternary alloys were grown on both GaSb and InAs substrates from In-rich solutions, under different temperature respectively.

Expression of syncytin in leukemia and lymphoma cells

Syncytin is a placenta-specific protein and generally believed to play a pivotal role in syncytiotrophoblast morphogenesis. In this study, transcripts of this gene were quantified by real-time RT-PCR and the translated products were measured by an indirect immunofluorescence assay. Results showed that syncytin was found to be expressed in all nine leukemia and lymphoma cell lines studied albeit at different levels and in 43 peripheral blood samples of 57 leukemia or lymphoma patients. Neither the transcripts nor the translated syncytin was detected in blood samples of normal individuals. In conclusion, peripheral blood syncytin may serve as a marker for leukemia and lymphoma. ©

Characterization of polymorphous silicon thin film and solar cells

Polymorphous silicon (pm-Si:H) films have been prepared by a new regime of plasma enhanced chemical vapour deposition in the region adjacent of phase transition from amorphous to microcrystalline state. Comparing to the conventional amorphous silicon (a-Si:H), the pm-Si:H has higher photoconductivity (sigma(ph)), better stability, and a broader light spectral response range in the longer wavelength range. It can be found from Raman spectra that there is a notable improvement in the medium range order. There are a blue shift for the stretching mode of IR spectra and a red shift for the wagging mode. The shifts are attributed to the variation of the microstructure. By using pm-Si:H film as intrinsic layer, a p-i-n junction solar cell was prepared with the initial efficiency of 8.51% and a stabilized efficiency of 8.01% (AM1.5, 100mw/cm(2)) at room temperature (T-R).

Characterization of diphasic nc-Si/a-Si : H thin films and solar cells

Hydrogenated silicon films with diphasic structure have been prepared by using a new regime of plasma enhanced chemical vapor deposition (PECVD) in the region adjacent to the phase transition from amorphous to crystal. line state. The photoelectronic and microstructural properties of the films have been characterized by the constant photocurrent method (CPM), Raman scattering and nuclear magnetic resonance (NMR). In comparison with typical hydrogenated amorphous silicon (a-Si:H), these diphasic films with a crystalline fraction less than 0.3 show a similar optical absorption coefficient, lower deep-defect densities and higher stability upon light soaking. By using the diphasic nc-Si/a-Si films a p-i-n junction solar cell has been prepared With an initial efficiency of 8.51 % and a stabilized efficiency of 8.02 % on an area of 0.126 cm(2) (AM1.5, 100 mW/cm(2)).

Inhibiting Survivin Expression Increases The Radiosensitivity of Human Hepatoma HepG2 Cells to High-LET Radiation

The influence of survivin expression on the radiosensitivity of tumor cells to high linear energy transfer (LET) radiation is investigated. Survivin-specific short-interfering RNA (siRNA) oligonucleotides were synthesized based on the survivin sequence provided by GenBank. Human hepatoma HepG2 cells were transfected with survivin-specific siRNA to inhibit its expressions. It was found that the transfection with surviving-specific siRNA increased the levels of G2/M arrest and the apoptotic rates induced by radiation in HepG2 cells. After exposure to high-LET carbon ions, a reduced clonogenic survival effect was observed in the cells treated with siRNA. These results show that survivin plays a key role in mediating the radioresistance of cells to high-LET radiation.

Preparation and characterization of multiwalled carbon nanotube-supported platinum for cathode catalysts of direct methanol fuel cells

Multiwalled carbon nanotube-supported Pt (Pt/MWNT) nanocomposites were prepared by both the aqueous solution reduction of a Pt salt (HCHO reduction) and the reduction of a Pt ion salt in ethylene glycol solution. For comparison, a Pt/XC-72 nanocomposite was also prepared by the EG method. The Pt/MWNT catalyst prepared by the EG method has a high and homogeneous dispersion of spherical Pt metal particles with a narrow particle-size distribution. TEM images show that the Pt particle size is in the range of 2-5 nm with a peak at 2.6 nm, which is consistent with 2.5 nm obtained from the XRD broadening calculation. Surface chemical modifications of MWNTs and water content in EG solvent are found to be the key factors in depositing Pt particles on MWNTs. In the case of the direct methanol fuel cell (DMFC) test, the Pt/MWNT catalyst prepared by EG reduction is slightly superior to the catalyst prepared by aqueous reduction and displays significantly higher performance than the Pt/XC-72 catalyst. These differences in catalytic performance between the MWNT-supported or the carbon black XC-72-supported catalysts are attributed to a greater dispersion of the supported Pt particles when the EG method is used, in contrast to aqueous HCHO reduction and to possible unique structural and higher electrical properties when contrasting MWNTs to carbon black XC-72 as a support.

Seed-bank development, germination and early seedling survival of two seagrass species from The Netherlands: Zostera marina L. and Zostera noltii hornem

Flowering and seed-bank development of annual Zostera marina L. and perennial Z. noltii hornem. were studied in the Zandkreek (S.W. Netherlands). Flowering of Z. noltii started at the end of June and continued until the end of September. A maximum of ca. 1000 flowering shoots (11% of the total amount of shoots per square metre) occurred in early August. Flowering of Z. marina started at the end of July and continued throughout October. Seed banks of both species appeared to be annual. Actual seed densities of Z. noltii were much lower than predicted on the basis of the amount of inflorescences.Germination was studied in the laboratory in relation to temperature (10, 20 and 30°C), salinity (1.0, 10.0, 20.0, 30.0 and 40.0‰) and stratification (at 4°C). Both species showed a maximal germination at 30°C and 1.0‰ salinity, decreasing with higher salinities and lower temperatures. Stratification stimulated germination only at salinities 20.0‰. Desiccation and anaerobia were lethal to Z. marina seeds. Seedlings of Z. marina survived best at 10°C and 10.0–20.0‰ salinity and those of Z. noltii survived best at 10°C and 1.0‰ salinity. Overall, seedlings of Z. marina survived better than those of Z. noltii.