514 research outputs found
Glomeruläre Läsionen bei Transplantatabstoßung
Zusammenfassung: Abstoßungsreaktionen sind die häufigste Ursache für ein Transplantatversagen nach Nierentransplantation. Glomeruläre Läsionen finden sich dabei relativ selten. Die thrombotische Mikroangiopathie und die Transplantatglomerulitis treten früh nach Transplantation auf, die Transplantatglomerulopathie bildet sich in der Regel erst nach längerer Zeit aus. Die morphologischen Befunde, in deren Zentrum ein Endothelschaden steht, und mögliche pathogenetische Mechanismen werden diskutier
On propagators and three-point functions in Landau gauge QCD and QCD-like theories
Recent progress in our studies of propagators and three-point functions in
Landau gauge for QCD and QCD-like theories is presented. Special emphasis is
put on the properties of the three-gluon vertex and the quark-gluon vertex. The
effect of unquenching is investigated. Furthermore, an exploratory study for a
large number of light flavours is described, from where clear evidence for the
qualitative behaviour of propagators in the so-called conformal window can be
extracted.Comment: 13 pages, 9 figures; Proceedings of the workshop QCD-TNT-III, ECT*
Trento, Sept. 2-6, 2013; references update
Heterogeneous T cell receptor Vβ gene repertoire in murine interstitial nephritis
Anti-tubular basement membrane disease (alpha TBM) produces T cell-mediated interstitial nephritis in SJL/J mice following immunization with heterologous renal tubular antigen. Initial mononuclear infiltrates appear in vivo after six to eight weeks, with subsequent progression to renal fibrosis and endstage kidney disease. Cultured lymph node derived nephritogenic T cells from these mice react to a small epitopic region of the 3M-1 target antigen and share a common amino acid motif in their V beta CDR3 regions. We now have used RT-PCR to further characterize the renal expression of T cell receptor (TcR) V beta gene repertoires during the course of this disease. Individual kidneys with focal mononuclear infiltrates characteristic of early alpha TBM disease express up to three different TcR V beta genes; however, the same V beta genes are not found in all kidneys at the same early stage of injury. DNA sequencing of the V beta RT-PCR products reveals a heterogeneous population of VDJ recombinations and deduced CDR3 amino acid sequences. Our studies do not support TcR V beta region gene restriction in histologically-detectable alpha TBM disease, but are more consistent with a dynamic, organ-specific autoimmune disease, directed at multiple autoantigenic epitopes
Deterministic polarization chaos from a laser diode
Fifty years after the invention of the laser diode and fourty years after the
report of the butterfly effect - i.e. the unpredictability of deterministic
chaos, it is said that a laser diode behaves like a damped nonlinear
oscillator. Hence no chaos can be generated unless with additional forcing or
parameter modulation. Here we report the first counter-example of a
free-running laser diode generating chaos. The underlying physics is a
nonlinear coupling between two elliptically polarized modes in a
vertical-cavity surface-emitting laser. We identify chaos in experimental
time-series and show theoretically the bifurcations leading to single- and
double-scroll attractors with characteristics similar to Lorenz chaos. The
reported polarization chaos resembles at first sight a noise-driven mode
hopping but shows opposite statistical properties. Our findings open up new
research areas that combine the high speed performances of microcavity lasers
with controllable and integrated sources of optical chaos.Comment: 13 pages, 5 figure
Uromodulin is expressed in renal primary cilia and UMOD mutations result in decreased ciliary uromodulin expression
Uromodulin (UMOD) mutations are responsible for three autosomal dominant tubulo-interstitial nephropathies including medullary cystic kidney disease type 2 (MCKD2), familial juvenile hyperuricemic nephropathy and glomerulocystic kidney disease. Symptoms include renal salt wasting, hyperuricemia, gout, hypertension and end-stage renal disease. MCKD is part of the ‘nephronophthisis-MCKD complex', a group of cystic kidney diseases. Both disorders have an indistinguishable histology and renal cysts are observed in either. For most genes mutated in cystic kidney disease, their proteins are expressed in the primary cilia/basal body complex. We identified seven novel UMOD mutations and were interested if UMOD protein was expressed in the primary renal cilia of human renal biopsies and if mutant UMOD would show a different expression pattern compared with that seen in control individuals. We demonstrate that UMOD is expressed in the primary cilia of renal tubules, using immunofluorescent studies in human kidney biopsy samples. The number of UMOD-positive primary cilia in UMOD patients is significantly decreased when compared with control samples. Additional immunofluorescence studies confirm ciliary expression of UMOD in cell culture. Ciliary expression of UMOD is also confirmed by electron microscopy. UMOD localization at the mitotic spindle poles and colocalization with other ciliary proteins such as nephrocystin-1 and kinesin family member 3A is demonstrated. Our data add UMOD to the group of proteins expressed in primary cilia, where mutations of the gene lead to cystic kidney diseas
RIXS observation of bond-directional nearest-neighbor excitations in the Kitaev material NaIrO
Spin-orbit coupling locks spin direction and spatial orientation and
generates, in semi-classical magnets, a local spin easy-axis and associated
ordering. Quantum spin-1/2's defy this fate: rather than spins becoming locally
anisotropic, the spin-spin interactions do. Consequently interactions become
dependent on the spatial orientation of bonds between spins, prime theoretical
examples of which are Kitaev magnets. Bond-directional interactions imply the
existence of bond-directional magnetic modes, predicted spin excitations that
render crystallographically equivalent bonds magnetically inequivalent, which
yet have remained elusive experimentally. Here we show that resonant inelastic
x-ray scattering allows us to explicitly probe the bond-directional character
of magnetic excitations. To do so, we use a scattering plane spanned by one
bond and the corresponding spin component and scan a range of momentum transfer
that encompasses multiple Brillouin zones. Applying this approach to
NaIrO we establish the different bond-directional characters of
magnetic excitations at 10 meV and 45 meV. Combined with the observation of
spin-spin correlations that are confined to a single bond, this experimentally
validates the Kitaev character of exchange interactions long proposed for this
material.Comment: 6 pages, 5 figures, plus 4 pages Supplementary Information (incl. 5
figures
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