59 research outputs found
Development of Thick-foil and Fine-pitch GEMs with a Laser Etching Technique
We have produced thick-foil and fine-pitch gas electron multipliers (GEMs)
using a laser etching technique. To improve production yield we have employed a
new material, Liquid Crystal Polymer, instead of polyimide as an insulator
layer. The effective gain of the thick-foil GEM with a hole pitch of 140 um, a
hole diameter of 70 um, and a thickness of 100 um reached a value of 10^4 at an
applied voltage of 720 V. The measured effective gain of the thick-foil and
fine-pitch GEM (80 um pitch, 40 um diameter, and 100 um thick) was similar to
that of the thick-foil GEM. The gain stability was measured for the thick-foil
and fine-pitch GEM, showing no significant increase or decrease as a function
of elapsed time from applying the high voltage. The gain stability over 3 h of
operation was about 0.5%. Gain mapping across the GEM showed a good uniformity
with a standard deviation of about 4%. The distribution of hole diameters
across the GEM was homogeneous with a standard deviation of about 3%. There was
no clear correlation between the gain and hole diameter maps.Comment: 21 pages, 9 figure
The Infection of Chicken Tracheal Epithelial Cells with a H6N1 Avian Influenza Virus
Sialic acids (SAs) linked to galactose (Gal) in Ξ±2,3- and Ξ±2,6-configurations are the receptors for avian and human influenza viruses, respectively. We demonstrate that chicken tracheal ciliated cells express Ξ±2,3-linked SA, while goblet cells mainly express Ξ±2,6-linked SA. In addition, the plant lectin MAL-II, but not MAA/MAL-I, is bound to the surface of goblet cells, suggesting that SA2,3-linked oligosaccharides with GalΞ²1β3GalNAc subterminal residues are specifically present on the goblet cells. Moreover, both Ξ±2,3- and Ξ±2,6-linked SAs are detected on single tracheal basal cells. At a low multiplicity of infection (MOI) avian influenza virus H6N1 is exclusively detected in the ciliated cells, suggesting that the ciliated cell is the major target cell of the H6N1 virus. At a MOI of 1, ciliated, goblet and basal cells are all permissive to the AIV infection. This result clearly elucidates the receptor distribution for the avian influenza virus among chicken tracheal epithelial cells and illustrates a primary cell model for evaluating the cell tropisms of respiratory viruses in poultry
Correlation Index-Based Responsible-Enzyme Gene Screening (CIRES), a Novel DNA Microarray-Based Method for Enzyme Gene Involved in Glycan Biosynthesis
BACKGROUND: Glycan biosynthesis occurs though a multi-step process that requires a variety of enzymes ranging from glycosyltransferases to those involved in cytosolic sugar metabolism. In many cases, glycan biosynthesis follows a glycan-specific, linear pathway. As glycosyltransferases are generally regulated at the level of transcription, assessing the overall transcriptional profile for glycan biosynthesis genes seems warranted. However, a systematic approach for assessing the correlation between glycan expression and glycan-related gene expression has not been reported previously. METHODOLOGY: To facilitate genetic analysis of glycan biosynthesis, we sought to correlate the expression of genes involved in cell-surface glycan formation with the expression of the glycans, as detected by glycan-recognizing probes. We performed cross-sample comparisons of gene expression profiles using a newly developed, glycan-focused cDNA microarray. Cell-surface glycan expression profiles were obtained using flow cytometry of cells stained with plant lectins. Pearson's correlation coefficients were calculated for these profiles and were used to identify enzyme genes correlated with glycan biosynthesis. CONCLUSIONS: This method, designated correlation index-based responsible-enzyme gene screening (CIRES), successfully identified genes already known to be involved in the biosynthesis of certain glycans. Our evaluation of CIRES indicates that it is useful for identifying genes involved in the biosynthesis of glycan chains that can be probed with lectins using flow cytometry
Avian Influenza Viruses Infect Primary Human Bronchial Epithelial Cells Unconstrained by Sialic Acid Ξ±2,3 Residues
Avian influenza viruses (AIV) are an important emerging threat to public health. It is thought that sialic acid (sia) receptors are barriers in cross-species transmission where the binding preferences of AIV and human influenza viruses are sias Ξ±2,3 versus Ξ±2,6, respectively. In this study, we show that a normal fully differentiated, primary human bronchial epithelial cell model is readily infected by low pathogenic H5N1, H5N2 and H5N3 AIV, which primarily bind to sia Ξ±2,3 moieties, and replicate in these cells independent of specific sias on the cell surface. NHBE cells treated with neuraminidase prior to infection are infected by AIV despite removal of sia Ξ±2,3 moieties. Following AIV infection, higher levels of IP-10 and RANTES are secreted compared to human influenza virus infection, indicating differential chemokine expression patterns, a feature that may contribute to differences in disease pathogenesis between avian and human influenza virus infections in humans
A putative carbohydrate-binding domain of the lactosebindingCytisus sessilifolius anti-H(O) lectin has a similar amino acid sequence to that of thel-fucose-bindingUlex europaeus anti-H(O) lectin
Real-time Parameter Estimation of Hydraulic Servo Actuator Systems Using Self-excited Oscillation Method (Online Identification of Approximated Transfer Function Composed of Integral and Second Order Lag Elements)
Systematic and Quantitative Identification of Cellular Glycan Regulation Using Correlation Index-Based Responsible Enzyme Gene Screening (CIRES)
Systematic and Quantitative Identification of Cellular Glycan Regulation Using Correlation Index-Based Responsible Gene Screening (CIRES)
Heavy Ion and Proton Irradiation of Gas Electron Multipliers With Liquid Crystal Polymer Insulator: Evaluation Tests for Use in Space
Gas electron multipliers with a liquid crystal polymer insulator (LCP-GEMs) can be employed as X-ray polarimeters in several satellite missions in low-earth orbit. To evaluate their resistance to radiation, LCP-GEMs were exposed to Fe ion and proton beams from the heavy-ion accelerator facility HIMAC, and the gas gain was monitored. The LCP-GEMs survived 14.4-year-equivalent irradiation by fully stripped Fe ions with an energy of 500 MeV nuc^(-1), which simulated galactic cosmic-ray ions. We also studied the degradation of the insulator layer of the LCP-GEMs by irradiation with 160 MeV protons to simulate geomagnetically trapped protons. After irradiation with protons for 31.6 years equivalent, no significant change in gain was observed
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