85 research outputs found
Symmetries, Currents and Conservation Laws of Self-Dual Gravity
We describe an infinite-dimensional algebra of hidden symmetries for the
self-dual gravity equations. Besides the known diffeomorphism-type symmetries
(affine extension of w(infinity) algebra), this algebra contains new hidden
symmetries, which are an affine extension of the Lorentz rotations. The full
symmetry algebra has both Kac-Moody and Virasoro-like generators, whose
exponentiation maps solutions of the field equations to other solutions.
Relations to problems of string theories are briefly discussed.Comment: 14 pages, LaTeX, the paper was reformatte
Selective solubilization of chlorosome proteins in Chloroflexus aurantiacus
AbstractProteins were solubilized selectively from chlorosomes of Chloroflexus aurantiacus by electrophoretic gel filtration according to Griebenow et al. Whereas the 11 kDa and 18 kDa proteins were extracted almost completely, the remaining modified chlorosomes contained high amounts of pigment and c-protein. It was concluded that the c-protein in contradiction to the publication by Griebenow et al. is indeed localized in the interior of Chloroflexus chlorosomes
A new possible binding site for bacteriochlorophyll b in a light-harvesting polypeptide of the bacterium Ectothiorhodospira halochloris
AbstractWhole cells from Ectothiorhodospira halochloris were extracted with an organic solvent mixture. At least five small hydrophobic polypeptides representing most probably the light harvesting polypeptides were purified by gel filtration and consecutive FPLC-RP chromatography. The complete amino acid sequence of a 7.4 kDa polypeptide was determined. The polypeptide shows a three domain structure, indicative of an integral membrane protein, similar to the structure of the light-harvesting polypeptides from purple non-sulfur bacteria. Sequence homologies to the β-LHPs of purple bacteria range from 23. 1° to 36.4°. The conserved intramembrane located histidine residue of the antenna polypeptides of purple non-sulfur bacteria, assigned as the possible binding site for bacteriochlorophyll, was found to be replaced by asparagine
Protein sequences bound to mineral surfaces persist into deep time.
Proteins persist longer in the fossil record than DNA, but the longevity, survival mechanisms and substrates remain contested. Here, we demonstrate the role of mineral binding in preserving the protein sequence in ostrich (Struthionidae) eggshell, including from the palaeontological sites of Laetoli (3.8 Ma) and Olduvai Gorge (1.3 Ma) in Tanzania. By tracking protein diagenesis back in time we find consistent patterns of preservation, demonstrating authenticity of the surviving sequences. Molecular dynamics simulations of struthiocalcin-1 and -2, the dominant proteins within the eggshell, reveal that distinct domains bind to the mineral surface. It is the domain with the strongest calculated binding energy to the calcite surface that is selectively preserved. Thermal age calculations demonstrate that the Laetoli and Olduvai peptides are 50 times older than any previously authenticated sequence (equivalent to ~16 Ma at a constant 10°C)
Light Dark Matter Search with a High-Resolution Athermal Phonon Detector Operated Above Ground
We present limits on spin-independent dark matter-nucleon interactions using
a Si athermal phonon detector with a baseline energy
resolution of
. This exclusion analysis sets the most
stringent dark matter-nucleon scattering cross-section limits achieved by a
cryogenic detector for dark matter particle masses from to
, with a raw exposure of
acquired at an above-ground facility. This work illustrates the scientific
potential of detectors with athermal phonon sensors with eV-scale energy
resolution for future dark matter searches.Comment: 7 pages, 4 figures, this version includes ancillary files from
official data releas
Atypical Hemolytic Uremic Syndrome
SummaryHemolytic uremic syndrome (HUS) is a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. The atypical form of HUS is a disease characterized by complement overactivation. Inherited defects in complement genes and acquired autoantibodies against complement regulatory proteins have been described. Incomplete penetrance of mutations in all predisposing genes is reported, suggesting that a precipitating event or trigger is required to unmask the complement regulatory deficiency. The underlying genetic defect predicts the prognosis both in native kidneys and after renal transplantation. The successful trials of the complement inhibitor eculizumab in the treatment of atypical HUS will revolutionize disease management
Bildungsstandards zwischen Politik und schulischem Alltag
Zuber J, Altrichter H, Heinrich M. Bildungsstandards zwischen Politik und schulischem Alltag. In: Zuber J, Altrichter H, Heinrich M, eds. Bildungsstandards zwischen Politik und schulischem Alltag. Educational Governance. Vol 42. Wiesbaden: Springer VS; 2018: XIII-XV
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