All organizations, whether for profit, not for profit, or government, face issues of information technology management. While the concerns involved may differ from organization to organization, the ...principles of good information technology management remain the same. Using a compilation of articles on various topics relating to technology manage
3D silicon pixel sensors: Recent test beam results Hansson, P.; Balbuena, J.; Barrera, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2011, Letnik:
628, Številka:
1
Journal Article
Recenzirano
The 3D silicon sensors aimed for the ATLAS pixel detector upgrade have been tested with a high energy pion beam at the CERN SPS in 2009. Two types of sensor layouts were tested: full-3D assemblies ...fabricated in Stanford, where the electrodes penetrate the entire silicon wafer thickness, and modified-3D assemblies fabricated at FBK-irst with partially overlapping electrodes. In both cases three read-out electrodes are ganged together to form pixels of dimension
50
×
400
μ
m
2
. Data on the pulse height distribution, tracking efficiency and resolution were collected for various particle incident angles, with and without a 1.6
T magnetic field. Data from a planar sensor of the type presently used in the ATLAS detector were used at the same time to give comparison.
Four monodisperse starburst oligomers bearing a 4,4′,4″‐tris(carbazol‐9‐yl)‐triphenylamine (TCTA) core and six oligofluorene arms are synthesized and characterized. The lengths of oligofluorene arms ...vary from one to four fluorene units, giving the starburst oligomers molecular weights ranging from 3072 to 10 068 Da (1 Da = 1.66 × 10–27 kg). All of the starburst oligomers have good film‐forming capabilities, and display bright, deep‐blue fluorescence (λmax = 395–416 nm) both in solution and in the solid state, with the quantum efficiencies of the films (ΦPL) varying between 27 and 88 %. Electrochemical studies demonstrate that these materials have large energy gaps, and are stable for both p‐doping and n‐doping processes. Electroluminescent devices are successfully fabricated using these materials as hole‐transporting emitters, and emit deep‐blue light. Devices with luminance values up to 1025 cd m–2 at 11 V and luminous efficiencies of 0.47 cd A–1 at 100 cd m–2 have been produced, which translates to an external quantum efficiency of 1.4 %. In addition, these large‐energy‐gap starburst oligomers are good host materials for red electrophosphorescence. The luminance of the red electrophosphorescent devices is as high as 4452 cd m–2, with a luminous efficiency of 4.31 cd A–1 at 15 mA cm–2: This value is much higher than those obtained from the commonly used hole‐transporting materials, such as poly(vinyl carbazole) (PVK) (1.10 cd A–1 at 16 mA cm–2).
Four monodisperse starburst oligomers bearing a 4,4′,4″‐tris(carbazol‐9‐yl)‐triphenylamine core and six uniform oligofluorene arms are synthesized (see figure). They display excellent photoluminescence and electroluminescence properties as hole‐transporting materials and deep‐blue‐light emitters; they also perform well as the host material for red‐electrophosphorescence emitters.
A capillary zone electrophoresis method is developed for the determination of aromatic organic acids and nitrophenols in atmospheric aerosols. The procedure is based on sampling atmospheric ...particulate matter on quartz fiber filters and the extraction and analysis of the extracts by capillary electrophoresis. Separation conditions are optimized by varying the pH and acetonitrile content of the electrolyte buffer. Separations in a 20% acetonitrile-20mM borate mixture (pH 9.9) are able to resolve all of the geometric isomers of hydroxybenzoic acid, phthalic acid, benzenetricarboxylic acid, and nitrophenol as well as 1,2,4,5- benzenetricarboxylic acid, m-toluic acid, and sulfosalicylic acid. A buffer consisting of 11% acetonitrile-20mM borate (pH 9.9) is found to be most suitable for the analysis of atmospheric aerosol samples. Detection limits are in the order of 40 to 130 ng/mL. Intersample migration time reproducibility is generally better than 1.5%, with day-to-day variations under 3%. A general extraction scheme using diethyl ether-HCl in combination with a preconcentration step is developed. Recoveries of spiked standards range from 59% to 102%, with relative standard deviations ranging from 2% to 17% for five determinations. The method is applied towards the analysis of ambient aerosol samples as well as vehicle emission studies with promising results, thus showing it to be a potential complement to already existing methodology for the analysis of organic acids and nitrophenols in atmospheric aerosols.
The development of glycomics increasingly requires the detection and quantification of large numbers of glycans, which is only partially achieved by current glycomics approaches. Taking advantage of ...selected reaction monitoring to enhance both sensitivity and selectivity, we report here a strategy termed targeted glycomics that enables highly sensitive and consistent identification and quantification of diverse glycans across multiple samples at the same time. In this proof‐of‐principle study, we validated the method by analyzing global N‐glycans expressed in different systems: single proteins, cancer cells, and serum samples. A dynamic range of three orders of magnitude was obtained for the detection of all five glycans released from ribonuclease B. The limit of detection of 80 attomole for Man9GlcNAc2 demonstrated the excellent sensitivity of the method. The capability of the strategy to identify diverse glycans was demonstrated by identification and detection of 162 different glycans and isomers from pancreatic cancer cells. The sensitivity of the method was illustrated further by the ability to detect eight glycans from 250 cancer cells and five glycans released from 100 cancer cells. In serum obtained from rabbits fed control diet or diet enriched with 2% cholesterol, differences to 42 glycans were accurately measured and this indicates that this strategy might find use in studies of biomarker discovery and validation.
Morganella morganii is a commensal Gram-negative bacterium that has long been known to produce an antigen bearing phosphocholine groups. We determined the structure of this O-chain antigen and found ...that its repeating unit also contains a free amino group and a second phosphate: This alternating charge character places the M. morganii O-chain polysaccharide into a small family of zwitterionic polysaccharides (ZPSs) known to induce T-cell-dependent immune responses via presentation by class II major histocompatibility complex (MHCII) molecules. In vitro binding assays demonstrate that this O-chain interacts with MHCII in a manner that competes with binding of the prototypical ZPS antigen PSA from Bacteroides fragilis, despite its lack of a helical structure. Cellular studies also showed that the M. morganii polysaccharide induces activation of CD4(+) T-cells. Antibody binding experiments using acid hydrolyzed fragments representing the monomer and higher oligomers of the repeating unit showed that the phosphocholine group was the dominant element of the epitope with an overall affinity (K(D)) of about 5 × 10(-5) M, a typical value for an IgM anti-carbohydrate antibody but much lower than the affinity for phosphocholine itself. These data show that the structure of the M. morganii polysaccharide contains a unique zwitterionic repeating unit which allows for immune recognition by T-cells, making it the first identified T-cell-dependent O-chain antigen.
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