Recognition of self-antigens is required for regulatory T (Treg) cells to exert dominant tolerance. However, the mechanism by which self-reactive thymocytes are diverted into the Treg cell subset is unclear. To address this question, we looked for the immediate precursors to Treg cells within Foxp3(-)CD4+CD8(-) thymocytes. By using intrathymic transfer, we found that the CD25hi subset is highly...

Mapping the initial reaction of implants with blood or cell culture medium is important for the understanding of the healing process in bone. In the present study, the formation of low crystalline carbonated hydroxyapatite (CHA) onto commercially pure titanium (Ti) implants from cell culture medium and blood, is described as an early event in bone healing at implants. The Ti-implants were incub...

Based on the concept of a Lévy copula to describe the dependence structure of a multivariate Lévy process we present a new estimation procedure. We consider a parametric model for the marginal Lévy processes as well as for the Lévy copula and estimate the parameters by a two-step procedure. We first estimate the parameters of the marginal processes, and then estimate in a second step only the d...

Polyimide is of great technical importance because of its excellent material properties (including chemical inertness and radiation resistance) which are maintained even at low and at high temperatures. When thin polyimide foils are irradiated with energetic heavy ions, long nanometric tracks are formed. Under suitable conditions, the damaged material along these tracks is dissolved and develop...

In order to reduce the effort needed to create self-separated, freestanding gallium nitride (GaN) layers by thick growth in hydride vapor phase epitaxy (HVPE), we established a two-step facet-controlled lateral overgrowth (FACELO) process in HVPE. Just as for the metalorganic vapor phase epitaxy (MOVPE) FACELO process, the template is produced by MOVPE growth directly on sapphire. This initial ...

The apparent inhibition constant, Kapp, for the blockade of P-glycoprotein (P-gp) by four drugs, verapamil, cyclosporin A, XR9576 (tariquidar), and vinblastine, was measured by studying their ability to inhibit daunorubicin and calcein-AM efflux from four strains of Ehrlich cells with different levels of drug resistance and P-gp content. For daunorubicin as a transport substrate, Kapp was indep...

An iterative solver based on the immersed interface method is proposed to solve the pressure in a two-fluid flow on a Cartesian grid. The iteration is constructed by introducing an unsteady term in the pressure Poisson equation. In each iteration step, a Helmholtz equation is solved on the Cartesian grid using FFT. The combination of the iteration and the immersed interface method enables the s...

In Arabidopsis, multisubunit RNA polymerases IV and V orchestrate RNA-directed DNA methylation (RdDM) and transcriptional silencing, but what identifies the loci to be silenced is unclear. We show that heritable silent locus identity at a specific subset of RdDM targets requires HISTONE DEACETYLASE 6 (HDA6) acting upstream of Pol IV recruitment and siRNA biogenesis. At these loci, epigenetic me...

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