110 research outputs found
Spontaneous alloying in binary metal microclusters - A molecular dynamics study -
Microcanonical molecular dynamics study of the spontaneous alloying(SA),
which is a manifestation of fast atomic diffusion in a nano-sized metal
cluster, is done in terms of a simple two dimensional binary Morse model.
Important features observed by Yasuda and Mori are well reproduced in our
simulation. The temperature dependence and size dependence of the SA phenomena
are extensively explored by examining long time dynamics. The dominant role of
negative heat of solution in completing the SA is also discussed. We point out
that a presence of melting surface induces the diffusion of core atoms even if
they are solid-like. In other words, the {\it surface melting} at substantially
low temperature plays a key role in attaining the SA.Comment: 15 pages, 12 fgures, Submitted to Phys.Rev.
Comparison of printed glycan array, suspension array and ELISA in the detection of human anti-glycan antibodies
Anti-glycan antibodies represent a vast and yet insufficiently investigated subpopulation of naturally occurring and adaptive antibodies in humans. Recently, a variety of glycan-based microarrays emerged, allowing high-throughput profiling of a large repertoire of antibodies. As there are no direct approaches for comparison and evaluation of multi-glycan assays we compared three glycan-based immunoassays, namely printed glycan array (PGA), fluorescent microsphere-based suspension array (SA) and ELISA for their efficacy and selectivity in profiling anti-glycan antibodies in a cohort of 48 patients with and without ovarian cancer. The ABO blood group glycan antigens were selected as well recognized ligands for sensitivity and specificity assessments. As another ligand we selected P1, a member of the P blood group system recently identified by PGA as a potential ovarian cancer biomarker. All three glyco-immunoassays reflected the known ABO blood groups with high performance. In contrast, anti-P1 antibody binding profiles displayed much lower concordance. Whilst anti-P1 antibody levels between benign controls and ovarian cancer patients were significantly discriminated using PGA (pâ=â0.004), we got only similar results using SA (pâ=â0.03) but not for ELISA. Our findings demonstrate that whilst assays were largely positively correlated, each presents unique characteristic features and should be validated by an independent patient cohort rather than another array technique. The variety between methods presumably reflects the differences in glycan presentation and the antigen/antibody ratio, assay conditions and detection technique. This indicates that the glycan-antibody interaction of interest has to guide the assay selection
Facile Preparation of Fluorescent Neoglycoproteins Using p-Nitrophenyl Anthranilate as a Heterobifunctional Linker
A facile preparation of neoglycoconjugates has been developed with a commercially available chemical, p-nitrophenyl anthranilate (PNPA), as a heterobifunctional linker. The two functional groups of PNPA, the aromatic amine and the p-nitrophenyl ester, are fully differentiated to selectively conjugate with glycans and other biomolecules containing nucleophiles. PNPA is efficiently conjugated with free reducing glycans via reductive amination. The glycanâPNPA conjugates (GPNPAs) can be easily purified and quantified by UV absorption. The active p-nitrophenyl ester in the GPNPA conjugates readily reacts with amines under mild conditions, and the resulting conjugates acquire strong fluorescence. This approach was used to prepare several fluorescent neoglycoproteins. The neoglycoproteins were covalently printed on activated glass slides and were bound by appropriate lectins recognizing the glycans
Synthesis of Glycopolymers for Microarray Applications via Ligation of Reducing Sugars to a Poly(acryloyl hydrazide) Scaffold
On crystal structure imaging of silicalite by HREM
High-resolution electron microscopy (HREM) images of silicalite (ZSM-5) along [010] were taken with a 400-kV EM with a resolution of 1.6 Ă
. The images contain a dark contrast in the centers of the main channels, where there are no atoms. This contrast is an artifact and is not appreciable in the HREM images which have been published so far. That this problem can be overcome by choosing the proper experimental conditions was confirmed by both computer-simulated and experimental HREM images. Computer image processing is also applicable to this kind of problem
Underlag för ÄtgÀrdsprioritering av barriÀrer i StockholmsomrÄdet
Stockholms stora trafikleder utgör, tillsammans med bebyggelse lÀngs och kring lederna, kraftiga barriÀrer för biologisk mÄngfald och friluftsliv. Ett 30-tal sÀrskilt vÀsentliga barriÀrer har tidigare identifierats inom ett regeringsuppdrag redovisat 2005. Banverket och VÀgverket tog dÄ fram ett gemensamt ÄtgÀrdsprogram för att ÄtgÀrda de mest vÀsentliga barriÀrerna av jÀrnvÀgar och vÀgar för friluftsliv och biologisk mÄngfald med tyngdpunkt pÄ större tÀtorter. Det arbetet genomfördes i bred samverkan och de barriÀrer som pekades ut i programmet finns ocksÄ till stor del förankrade i RUFS Stockholms lÀns grönstruktur och Svaga gröna samband. I denna rapport redovisas en kvantitativ metod för att systematiskt och transparent vÀrdera olika faktorer som pÄverkar barriÀreffekterna av transportinfrastrukturen. En utgÄngspunkt Àr den riktlinje för landskap som Trafikverket antog 2016. Avsikten Àr att rapportens resultat ska utgöra ett underlag och stöd för en tydligare prioritering av tidigare identifierade större barriÀrer av vÀgar och jÀrnvÀgar i Stockholms lÀn
Underlag för ÄtgÀrdsprioritering av barriÀrer i StockholmsomrÄdet
Stockholms stora trafikleder utgör, tillsammans med bebyggelse lÀngs och kring lederna, kraftiga barriÀrer för biologisk mÄngfald och friluftsliv. Ett 30-tal sÀrskilt vÀsentliga barriÀrer har tidigare identifierats inom ett regeringsuppdrag redovisat 2005. Banverket och VÀgverket tog dÄ fram ett gemensamt ÄtgÀrdsprogram för att ÄtgÀrda de mest vÀsentliga barriÀrerna av jÀrnvÀgar och vÀgar för friluftsliv och biologisk mÄngfald med tyngdpunkt pÄ större tÀtorter. Det arbetet genomfördes i bred samverkan och de barriÀrer som pekades ut i programmet finns ocksÄ till stor del förankrade i RUFS Stockholms lÀns grönstruktur och Svaga gröna samband. I denna rapport redovisas en kvantitativ metod för att systematiskt och transparent vÀrdera olika faktorer som pÄverkar barriÀreffekterna av transportinfrastrukturen. En utgÄngspunkt Àr den riktlinje för landskap som Trafikverket antog 2016. Avsikten Àr att rapportens resultat ska utgöra ett underlag och stöd för en tydligare prioritering av tidigare identifierade större barriÀrer av vÀgar och jÀrnvÀgar i Stockholms lÀn
Structural investigations of new calcium - rare earth (R) oxyborates with the composition Ca4RO(BO3)3
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