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