17 research outputs found
Novel synovial fluid recovery method allows for quantification of a marker of arthritis in mice
SummaryObjectiveWe evaluated three methodologies – a calcium sodium alginate compound (CSAC), polyacrylate beads (PABs), and Whatman paper recovery (WPR) – for the ability to recover synovial fluid (SF) from mouse knees in a manner that facilitated biochemical marker analysis.MethodsPilot testing of each of these recovery vehicles was conducted using small volumes of waste human SF. CSAC emerged as the method of choice, and was used to recover and quantify SF from the knees of C57BL/6 mice (n=12), six of which were given left knee articular fractures. SF concentrations of cartilage oligomeric matrix protein (COMP) were measured by enzyme-linked immunosorbent assay.ResultsThe mean concentration ratio [(COMPleft knee)/(COMPright knee)] was higher in the mice subjected to articular fracture when compared to the non-fracture mice (P=0.026). The mean total COMP ratio (taking into account the quantitative recovery of SF) best discriminated between fracture and non-fracture knees (P=0.004).ConclusionsOur results provide the first direct evidence of accelerated joint tissue turnover in a mouse model responding to acute joint injury. These data strongly suggest that mouse SF recovery is feasible and that biomarker analysis of collected SF samples can augment traditional histological analyses in mouse models of arthritis
A Solvable Regime of Disorder and Interactions in Ballistic Nanostructures, Part I: Consequences for Coulomb Blockade
We provide a framework for analyzing the problem of interacting electrons in
a ballistic quantum dot with chaotic boundary conditions within an energy
(the Thouless energy) of the Fermi energy. Within this window we show that the
interactions can be characterized by Landau Fermi liquid parameters. When ,
the dimensionless conductance of the dot, is large, we find that the disordered
interacting problem can be solved in a saddle-point approximation which becomes
exact as (as in a large-N theory). The infinite theory shows a
transition to a strong-coupling phase characterized by the same order parameter
as in the Pomeranchuk transition in clean systems (a spontaneous
interaction-induced Fermi surface distortion), but smeared and pinned by
disorder. At finite , the two phases and critical point evolve into three
regimes in the plane -- weak- and strong-coupling regimes separated
by crossover lines from a quantum-critical regime controlled by the quantum
critical point. In the strong-coupling and quantum-critical regions, the
quasiparticle acquires a width of the same order as the level spacing
within a few 's of the Fermi energy due to coupling to collective
excitations. In the strong coupling regime if is odd, the dot will (if
isolated) cross over from the orthogonal to unitary ensemble for an
exponentially small external flux, or will (if strongly coupled to leads) break
time-reversal symmetry spontaneously.Comment: 33 pages, 14 figures. Very minor changes. We have clarified that we
are treating charge-channel instabilities in spinful systems, leaving
spin-channel instabilities for future work. No substantive results are
change
Metamorphosis and Taxonomy of Andreev Bound States
We analyze the spatial and energy dependence of the local density of states
in a SNS junction. We model our system as a one-dimensional tight-binding chain
which we solve exactly by numerical diagonalization. We calculate the
dependence of the Andreev bound states on position, phase difference, gate
voltage, and coupling with the superconducting leads. Our results confirm the
physics predicted by certain analytical approximations, but reveal a much
richer set of phenomena beyond the grasp of these approximations, such as the
metamorphosis of the discrete states of the normal link (the normal bound
states) into Andreev bound states as the leads become superconducting.Comment: 23 pages, 15 figure
The Perceived Equity and Equality of Sexual Practices Scale: Validation of a measure of equity and equality within couples
Novel synovial fluid recovery method allows for quantification of a marker of arthritis in mice
Reorientation of Mispositioned Spindles in Short Astral Microtubule Mutant spc72Δ Is Dependent on Spindle Pole Body Outer Plaque and Kar3 Motor Protein
Nuclear migration and positioning in Saccharomyces cerevisiae depend on long astral microtubules emanating from the spindle pole bodies (SPBs). Herein, we show by in vivo fluorescence microscopy that cells lacking Spc72, the SPB receptor of the cytoplasmic γ-tubulin complex, can only generate very short (<1 μm) and unstable astral microtubules. Consequently, nuclear migration to the bud neck and orientation of the anaphase spindle along the mother-bud axis are absent in these cells. However, SPC72 deletion is not lethal because elongated but misaligned spindles can frequently reorient in mother cells, permitting delayed but otherwise correct nuclear segregation. High-resolution time-lapse sequences revealed that this spindle reorientation was most likely accomplished by cortex interactions of the very short astral microtubules. In addition, a set of double mutants suggested that reorientation was dependent on the SPB outer plaque and the astral microtubule motor function of Kar3 but not Kip2/Kip3/Dhc1, or the cortex components Kar9/Num1. Our observations suggest that Spc72 is required for astral microtubule formation at the SPB half-bridge and for stabilization of astral microtubules at the SPB outer plaque. In addition, our data exclude involvement of Spc72 in spindle formation and elongation functions