Human thymoma-associated mutation of the GTF2I transcription factor impairs thymic epithelial progenitor differentiation in mice

Few human tumours present with a recurrent pathognomonic mutation in a transcription factor. Thymomas are an exception, with the majority of some subtypes exhibiting a distinct somatically acquired missense mutation in the general transcription factor GTF2I. Co-dominant expression of wild-type and mutated forms of Gtf2i in the mouse thymic epithelium is associated with aberrant thymic architecture and reduced thymopoietic activity. Phenotypic and molecular characterization of the mutant epithelium indicates that medullary differentiation is particularly affected as a result of impaired differentiation of bi-potent epithelial progenitors. The resulting gene expression signature is dominated by that of immature cortex-like thymic epithelial cells. TCR repertoire analysis of the cytopenic T cell compartment indicates efficient intrathymic selection; hence, despite marked homeostatic proliferation of T cell clones, autoimmunity is not observed. Thus, our transgenic mouse model recapitulates some aspects of the pathophysiology of a genetically defined type of human thymoma

The Vector Analyzing Power in Elastic Electron-Proton Scattering

We compute the vector analyzing power (VAP) for the elastic scattering of transversely polarized electrons from protons at low energies using an effective theory of electrons, protons, and photons. We study all contributions through second order in $E/M$, where $E$ and $M$ are the electron energy and nucleon mass, respectively. The leading order VAP arises from the imaginary part of the interference of one- and two-photon exchange amplitudes. Sub-leading contributions are generated by the nucleon magnetic moment and charge radius as well as recoil corrections to the leading-order amplitude. Working to ${\cal O}(E/M)^2$, we obtain a prediction for $A_n$ that is free of unknown parameters and that agrees with the recent measurement of the VAP in backward angle $ep$ scattering.Comment: 24 pages, 11 figures. Typos fixe

Efficient generation of neural stem cell-like cells from adult human bone marrow stromal cells

Clonogenic neural stem cells (NSCs) are self-renewing cells that maintain the capacity to differentiate into brain-specific cell types, and may also replace or repair diseased brain tissue. NSCs can be directly isolated from fetal or adult nervous tissue, or derived from embryonic stem cells. Here, we describe the efficient conversion of human adult bone marrow stromal cells (hMSC) into a neural stem cell-like population (hmNSC, for human marrow-derived NSC-like cells). These cells grow in neurosphere-like structures, express high levels of early neuroectodermal markers, such as the proneural genes NeuroD1, Neurog2, MSl1 as well as otx1 and nestin, but lose the characteristics of mesodermal stromal cells. In the presence of selected growth factors, hmNSCs can be differentiated into the three main neural phenotypes: astroglia, oligodendroglia and neurons. Clonal analysis demonstrates that individual hmNSCs are multipotent and retain the capacity to generate both glia and neurons. Our cell culture system provides a powerful tool for investigating the molecular mechanisms of neural differentiation in adult human NSCs. hmNSCs may therefore ultimately help to treat acute and chronic neurodegenerative diseases

Exploring dark matter microphysics with galaxy surveys

We use present cosmological observations and forecasts of future experiments to illustrate the power of large-scale structure (LSS) surveys in probing dark matter (DM) microphysics and unveiling potential deviations from the standard ΛCDM scenario. To quantify this statement, we focus on an extension of ΛCDM with DM-neutrino scattering, which leaves a distinctive imprint on the angular and matter power spectra. After finding that future CMB experiments (such as COrE+) will not significantly improve the constraints set by the Planck satellite, we show that the next generation of galaxy clustering surveys (such as DESI) could play a leading role in constraining alternative cosmologies and even have the potential to make a discovery. Typically we find that DESI would be an order of magnitude more sensitive to DM interactions than Planck, thus probing effects that until now have only been accessible via N-body simulations

Spin liquid in a single crystal of the frustrated diamond lattice antiferromagnet CoAl2O4

We study spin liquid in the frustrated diamond lattice antiferromagnet CoAl2O4 by means of single crystal neutron scattering in zero and applied magnetic field. The magnetically ordered phase appearing below TN=8 K remains nonconventional down to 1.5 K. The magnetic Bragg peaks at the q=0 positions remain broad and their profiles have strong Lorentzian contribution. Additionally, they are connected by weak diffuse streaks along the directions. These observations are explained within the spiral spin liquid model as short-range magnetic correlations of spirals populated at these finite temperatures, as the energy minimum around q=0 is flat and the energy of excited states with q=(111) is low. The agreement is only qualitative, leading us to suspect that microstructure effects are also important. Magnetic field significantly perturbs spin correlations. The 1.5 K static magnetic moment increases from 1.58 mB/Co at zero field to 2.08 mB/Co at 10 T, while the magnetic peaks, being still broad, acquire almost Gaussian profile. Spin excitations are rather conventional spin waves at zero field, resulting in the exchange parameters J1=0.92(1) meV, J2=0.101(2) meV and the anisotropy term D=-0.0089(2) meV for CoAl2O4. The application of a magnetic field leads to a pronounced broadening of the excitations at the zone center, which at 10 T appear gapless and nearly featureless

Practical Quantum Key Distribution with Polarization-Entangled Photons

We present an entangled-state quantum cryptography system that operated for the first time in a real world application scenario. The full key generation protocol was performed in real time between two distributed embedded hardware devices, which were connected by 1.45 km of optical fiber, installed for this experiment in the Vienna sewage system. The generated quantum key was immediately handed over and used by a secure communication application.Comment: 5 pages, 3 figure