59 research outputs found

    Search for pair-produced resonances decaying to quark pairs in proton-proton collisions at root s=13 TeV

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    A general search for the pair production of resonances, each decaying to two quarks, is reported. The search is conducted separately for heavier resonances (masses above 400 GeV), where each of the four final-state quarks generates a hadronic jet resulting in a four-jet signature, and for lighter resonances (masses between 80 and 400 GeV), where the pair of quarks from each resonance is collimated and reconstructed as a single jet resulting in a two-jet signature. In addition, a b-tagged selection is applied to target resonances with a bottom quark in the final state. The analysis uses data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 35.9 fb(-1), from proton-proton collisions at a center-of-mass energy of 13 TeV. The mass spectra are analyzed for the presence of new resonances, and are found to be consistent with standard model expectations. The results are interpreted in the framework of R-parity-violating supersymmetry assuming the pair production of scalar top quarks decaying via the hadronic coupling lambda ''(312) or lambda ''(323) and upper limits on the cross section as a function of the top squark mass are set. These results probe a wider range of masses than previously explored at the LHC, and extend the top squark mass limits in the (t) over tilde -> qq' scenario.Peer reviewe

    Stage-Specific Proteome Signatures in Early Bovine Embryo Development

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    Development of early embryonic stages before activation of the embryonic genome depends on sufficiently stored products of the maternal genome, adequate recruitment and degradation of mRNAs, as well as activation, deactivation, and relocation of proteins. By application of an isobaric tagging for relative and absolute quantification (iTRAQ)-based approach, the proteomes of bovine embryos at the zygote and 2-cell and 4-cell stage with MII oocytes as a reference were quantitatively analyzed. Of 1072 quantified proteins, 87 differed significantly in abundance between the four stages. The proteomes of 2-cell and 4-cell embryos differed most from the reference MII oocyte, and a considerable fraction of proteins continuously increased in abundance during the stages analyzed, despite a strongly attenuated rate of translation reported for this period. Bioinformatic analysis revealed particularly interesting proteins involved in the p53 pathway, lipid metabolism, and mitosis. Verification of iTRAQ results by targeted SRM (selected reaction monitoring) analysis revealed excellent agreement for all five proteins analyzed. By principal component analysis, SRM quantifications comprising a panel of only five proteins were shown to discriminate between all four developmental stages analyzed here. For future experiments, an expanded SRM protein panel will provide the potential to detect developmental disturbances with high sensitivity and enable first insights into the underlying molecular pathways

    Systematic Investigations on 1,2,3-Triazole-Based Compounds Capable of Second Harmonic Generation

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    1,2,3-Triazole-functionalized ene–yne compounds, synthesized by thiophene (selenophene) ring fragmentation followed by azide–alkyne cycloaddition, were investigated as a basis for nonlinear optical (NLO) materials capable of second harmonic generation (SHG). The structure–property relationship was mapped by systematic variation of the molecular scaffold, viz., elongation of the alkyl groups, isomerizations of both the double bond as well as the triazole moiety, sulfur oxidations, and a sulfur–selenium exchange. Nine novel molecular compounds were synthesized, of which eight are solids at room temperature. The latter were characterized by single-crystal X-ray diffraction (XRD). Five crystal structures lacked of inversion symmetry, a prerequisite for NLO activity. The corresponding materials were examined regarding SHG, UV–vis absorption, and powder XRD. By substituting S for Se, we were able to increase the SH intensity by a factor of 20. On the basis of the results, we propose a strategy to further improve the SHG efficiency of this class of materials

    Ethyne-Linked Push–Pull Chromophores: Implications of Crystal Structure and Molecular Electronics on the Quadric Nonlinear Activity

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    Three ethyne-linked push–pull materials consisting of a dimethylaniline donor and acceptors of increasing electron-withdrawing strength were prepared as nonlinear optical chromophores. Despite a high similarity of the molecular structures, all three materials featured unrelated non-centrosymmetric crystallization behavior. One of the compounds exhibits a remarkable packing with <i>Z</i>′ = 16 molecules in the asymmetric unit forming two interpenetrating subsystems. Inspection of the nonlinear optical activity of single crystalline powders revealed an extraordinarily efficient second harmonic generation of one of the materials with a 1200-fold increased second harmonic response compared to potassium dihydrogen phosphate. The second harmonic generation efficiency of the materials under investigation has been related to both the intrinsic molecular properties as well as the alignment of the individual chromophores within the crystal packing, highlighting the importance of a multidisciplinary approach to understand the properties of nonlinear optical materials

    Expression Changes and Novel Interaction Partners of Talin 1 in Effector Cells of Autoimmune Uveitis

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    Autoimmune uveitis is characterized by crossing of blood-retinal barrier (BRB) by autoaggressive immune cells. Equine recurrent uveitis (ERU) is a valuable spontaneous model for autoimmune uveitis and analyses of differentially expressed proteins in ERU unraveled changed protein clusters in target tissues and immune system. Healthy eyes are devoid of leukocytes. In ERU, however, leukocytes enter the inner eye and subsequently destroy it. Molecular mechanisms enabling cell migration through BRB still remain elusive. Previously, we detected decreased talin 1 expression in blood-derived granulocytes of ERU cases, linking the innate immune system to ERU. Because changes in leukocyte protein expression pattern may play a role in pathological abnormalities leading to migration ability, we aimed at identifying interactors of talin 1 in leukocytes with immunoprecipitation, followed by LC–MS/MS for candidate identification. This enabled us to identify CD90 (Thy1) as novel interactor of talin 1 besides several other interactors. In blood-derived granulocytes from healthy individuals, CD90 was highly abundant and significantly reduced in ERU, especially in effector cells. Connection between talin 1 and CD90 and their expression differences in inflammation is an interesting novel finding allowing deeper insight into immune response of innate immune system and granulocyte migration ability in this organ-specific autoimmune disease

    Fluorescent Modular Boron Systems Based on NNN- and ONO-Tridentate Ligands: Self-Assembly and Cell Imaging

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    We have synthesized a series of new fluorescent boron systems <b>1a</b>–<b>c</b> and <b>2a</b>–<b>d</b> based on nitrogen (NNN) or nitrogen and oxygen (ONO)-containing tridentate ligands. These novel dyes are characterized by high thermal and chemical stability. They show large Stokes shifts (mostly above 3200 cm<sup>–1</sup>) and quantum yields in solution and in the solid state up to 40%. The easy, modular synthesis facilitates the convenient variation of the axial substituent on the central boron atom, allowing the functionalization of this dye for biochemical use. Introducing a long alkyl chain with a phenyl spacer at this axial position enables the self-assembly of the boron compound <b>2d</b> to form a fluorescent vesicle, which is able to encapsulate small molecules such as sulforhodamine. Additionally, boron compound <b>2d</b> was found to serve as a dye for cell imaging since it has the capability of binding to the nuclear membranes of HeLa cells. With phospholipids such as DOPC, giant unilamelar vesicles (GUV) are formed. These results demonstrate the wide applicability of this new boron system in supramolecular and medicinal chemistry

    Fluorescent Modular Boron Systems Based on NNN- and ONO-Tridentate Ligands: Self-Assembly and Cell Imaging

    No full text
    We have synthesized a series of new fluorescent boron systems <b>1a</b>–<b>c</b> and <b>2a</b>–<b>d</b> based on nitrogen (NNN) or nitrogen and oxygen (ONO)-containing tridentate ligands. These novel dyes are characterized by high thermal and chemical stability. They show large Stokes shifts (mostly above 3200 cm<sup>–1</sup>) and quantum yields in solution and in the solid state up to 40%. The easy, modular synthesis facilitates the convenient variation of the axial substituent on the central boron atom, allowing the functionalization of this dye for biochemical use. Introducing a long alkyl chain with a phenyl spacer at this axial position enables the self-assembly of the boron compound <b>2d</b> to form a fluorescent vesicle, which is able to encapsulate small molecules such as sulforhodamine. Additionally, boron compound <b>2d</b> was found to serve as a dye for cell imaging since it has the capability of binding to the nuclear membranes of HeLa cells. With phospholipids such as DOPC, giant unilamelar vesicles (GUV) are formed. These results demonstrate the wide applicability of this new boron system in supramolecular and medicinal chemistry
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