1,256,168 research outputs found
Dp-minimality: invariant types and dp-rank
This paper has two parts. In the first one, we prove that an invariant
dp-minimal type is either finitely satisfiable or definable. We also prove that
a definable version of the (p,q)-theorem holds in dp-minimal theories of small
or medium directionality. In the second part, we study dp-rank in dp-minimal
theories and show that it enjoys many nice properties. It is continuous,
definable in families and it can be characterised geometrically with no mention
of indiscernible sequences. In particular, if the structure expands a divisible
ordered abelian group, then dp-rank coincides with the dimension coming from
the order.Comment: New section added on dp-rank and the appendix with Sergei Starchenko
is now a separate pape
Witnessing dp-rank
We prove that in NTP_2 theories if p is a dependent type with dp-rank >=
\kappa, then this can be witnessed by indiscernible sequences of tuples
satisfying p. If p has dp-rank infinity, then this can be witnessed by
singletons (in any theory)
On the String Pair Creation in Dp-Dp' Brane System
We address the bosonic string pair creation in a system of parallel Dp-Dp'
(p<p') branes by applying the path integral formalism. We drive the string pair
creation rate by calculating the one loop vacuum amplitude of the setup in
presence of the background electric field defined over the Dp'-brane. It is
pointed out that just the components of the electric field defined over the
spatial directions (the common directions along which the both D-branes are
extended) give rise to the pair creationComment: Accepted for publication in Mod. Phys. Lett.
Mott transition in cuprate high-temperature superconductors
In this study, we investigate the metal-insulator transition of charge
transfer type in high-temperature cuprates. We first show that we must
introduce a new band parameter in the three-band d-p model to reproduce the
Fermi surface of high temperature cuprates such as BSCCO, YBCO and Hg1201. We
present a new wave function of a Mott insulator based on the improved
Gutzwiller function, and show that there is a transition from a metal to a
charge-transfer insulator for such parameters by using the variational Monte
Carlo method. This transition occurs when the level difference
between d and p orbitals reaches a
critical value . The energy gain , measured from the
limit of large , is proportional to for
: . We
obtain using the realistic band parameters
The role of HLA-DP mismatches and donor specific HLA-DP antibodies in kidney transplantation : a case series
BACKGROUND:
The impact of HLA-DP mismatches on renal allograft outcome is still poorly understood and is suggested to be less than that of the other HLA loci. The common association of HLA-DP donor-specific antibodies (DSA) with other DSA obviates the evaluation of the actual effect of HLA-DP DSA.
METHODS:
From a large multicenter data collection, we retrospectively evaluated the significance of HLA-DP DSA on transplant outcome and the immunogenicity of HLA-DP eplet mismatches with respect to the induction of HLA-DP DSA. Furthermore, we evaluated the association between the MFI of HLA-DP antibodies detected in Luminex assays and the outcome of flowcytometric/complement-dependent cytotoxicity (CDC) crossmatches.
RESULTS:
In patients with isolated pretransplant HLA-DP antibodies (N = 13), 6 experienced antibody-mediated rejection (AMR) and 3 patients lost their graft. In HLAMatchmaker analysis of HLA-DP mismatches (N = 72), HLA-DP DSA developed after cessation of immunosuppression in all cases with 84DEAV (N = 14), in 86% of cases with 85GPM (N = 6/7), in 50% of cases with 56E (N = 6/12) and in 40% of cases with 56A mismatch (N = 2/5). Correlation analysis between isolated HLA-DP DSA MFI and crossmatches (N = 90) showed negative crossmatch results with HLA-DP DSA MFI <2000 (N = 14). Below an MFI of 10,000 CDC crossmatches were also negative (N = 33). Above these MFI values both positive (N = 35) and negative (N = 16) crossmatch results were generated.
CONCLUSIONS:
Isolated HLA-DP DSA are rare, yet constitute a significant risk for AMR. We identified high-risk eplet mismatches that can lead to HLA-DP DSA formation. We therefore recommend HLA-DP typing to perform HLA-DP DSA analysis before transplantation. HLA-DP DSA with high MFI were not always correlated with positive crossmatch results
Photophysics, Molecular Reorientation in Solution and X-Ray Structure of a New Fluorescent Probe 1,7-Diazaperylene
A new fluorescent molecule 1,7-diazaperylene (DP) has been investigated by means of time-resolved and steady-state polarized fluorescence spectroscopy, as well as X-ray spectroscopy. Absorption and fluorescence spectra of DP in solution are similar to those of perylene. However, absorption and fluorescence spectra of 2,8-dimethoxy DP and 2,8-dipentyloxy DP in solution are red-shifted by ca. 55 nm relative to perylene. The fluorescence decay of DP is exponential with a lifetime of 5.1 ns in ethanol, 4.9 ns in glycerol and 4.3 ns in paraffin oil. The radiative lifetime in ethanol was calculated to be 6.3 ns for DP, 8.0 ns for 2,8-dimethoxy DP and 7.6 ns for 2,8-dipentyloxy DP. The calculated fluorescence quantum yields of 0.8 for DP and its alkoxy derivatives in ethanol, are in good agreement with those obtained from measurements. The calculated Förster radius is 37.2 ± 1 Å for DP and 41.9 ± 1 Å for its alkoxy derivatives in ethanol. Examining the S0 S1 transition, we obtain a limiting fluorescence anisotropy of r0 0.38 for DP and its alkoxy derivatives. The rotational rates of DP in paraffin oil and glycerol were compared to that of perylene. In paraffin oil both molecules show an almost identical biexponential decay of the fluorescence anisotropy, which is compatible with a rotational motion like an oblate ellipsoid. The fluorescence anisotropy is monoexponential for DP in glycerol, and DP appears to rotate like a spherical particle while perylene in glycerol appears to rotate like an oblate ellipsoid. Moreover, the rotational diffusion constant, corresponding to rotation about an axis in the aromatic plane (D), is the same for both DP and perylene in glycerol
p-p' Branes in PP-wave Background
We present several supergravity solutions corresponding to both Dp, as well
as Dp-Dp' systems, in NS-NS and R-R PP-wave background originating from AdS_3
times S^3 times R^4. The Dp brane solutions, p=1,..,5 are fully localized,
whereas Dp-Dp' are localized along common transverse directions. We also
discuss the supersymmetry properties of these solutions and the worldsheet
construction for the p-p' system.Comment: 17 pages, v5: supergrav. solns. corrected, v6: more results added:
now includes p-p' branes in both NS-NS and R-R PP-wave background, some
restructuring of the tex
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