Changes in mRNA expression of members of TGFB1-associated pathways in human leukocytes during EBV infection.

Transforming growth factor ß 1 (TGFB1) likely contributes to the pathogenesis of Epstein-Barr virus (EBV)-mediated cancer. A microarray containing 59 probes for detecting mRNA of members of TGFB1-associated pathways was developed. mRNA expression of TGFB1 receptors and members of connected pathways were examined in peripheral blood leukocytes of patients during acute EBV infection and after recovery. TGFB1 and TGFBR2 mRNA expression was increased in patients with EBV infection. Similarly, mRNA expression of protein kinase C (PRKCB), MAP3K7, PDLIM7, and other members of TGFB1 and NF-κB signaling pathways increased. A shift of mRNA transcript variant expression of some key members (TGFBR2, PRKCB, and NFKBIB) of involved signaling pathways was detected. After the patients' recovery, most of the altered mRNA expression has been normalized. We speculate that in patients with EBV infection, members of TGFB1-associated pathways contribute to the suppression of proapoptotic and induction of pro-survival factors in leukocytes. The modulation of TGFB1-associated pathways may be considered as a potential risk factor in the development of EBV-associated tumors in patients with acute EBV infection.

Observation of Néel-type skyrmions in acentric self-intercalated Cr1+δTe2.

Transition-metal dichalcogenides intercalated with 3d-transition metals within the van der Waals (vdW) gaps have been the focus of intense investigations owing to their fascinating structural and magnetic properties. At certain concentrations the intercalated atoms form ordered superstructures that exhibit ferromagnetic or anti-ferromagnetic ordering. Here we show that the self-intercalated compound Cr1+δTe2 with δ ≈ 0.3 exhibits a new, so far unseen, three-dimensionally ordered (2×2×2) superstructure. Furthermore, high resolution X-ray diffraction reveals that there is an asymmetric occupation of the two inequivalent vdW gaps in the unit cell. The structure thus lacks inversion symmetry, which, thereby, allows for chiral non-collinear magnetic nanostructures. Indeed, Néel-type skyrmions are directly observed using Lorentz transmission electron microscopy. The skyrmions are stable within the accessible temperature range (100-200 K) as well as in zero magnetic field. The diameter of the Néel skyrmions increases with lamella thickness and varies with applied magnetic field, indicating the role of long-range dipole fields. Our studies show that self-intercalation in vdW materials is a novel route to the formation of synthetic non-collinear spin textures.

Superconductivity up to 243 K in the yttrium-hydrogen system under high pressure.

The discovery of superconducting H3S with a critical temperature Tc∼200 K opened a door to room temperature superconductivity and stimulated further extensive studies of hydrogen-rich compounds stabilized by high pressure. Here, we report a comprehensive study of the yttrium-hydrogen system with the highest predicted Tcs among binary compounds and discuss the contradictions between different theoretical calculations and experimental data. We synthesized yttrium hydrides with the compositions of YH3, YH4, YH6 and YH9 in a diamond anvil cell and studied their crystal structures, electrical and magnetic transport properties, and isotopic effects. We found superconductivity in the Im-3m YH6 and P63/mmc YH9 phases with maximal Tcs of ∼220 K at 183 GPa and ∼243 K at 201 GPa, respectively. Fm-3m YH10 with the highest predicted Tc > 300 K was not observed in our experiments, and instead, YH9 was found to be the hydrogen-richest yttrium hydride in the studied pressure and temperature range up to record 410 GPa and 2250 K.

Superconducting phase diagram of H3S under high magnetic fields.

The discovery of superconductivity at 260 K in hydrogen-rich compounds like LaH10 re-invigorated the quest for room temperature superconductivity. Here, we report the temperature dependence of the upper critical fields µ0Hc2(T) of superconducting H3S under a record-high combination of applied pressures up to 160 GPa and fields up to 65 T. We find that Hc2(T) displays a linear dependence on temperature over an extended range as found in multigap or in strongly-coupled superconductors, thus deviating from conventional Werthamer, Helfand, and Hohenberg (WHH) formalism. The best fit of Hc2(T) to the WHH formalism yields negligible values for the Maki parameter α and the spin-orbit scattering constant λSO. However, Hc2(T) is well-described by a model based on strong coupling superconductivity with a coupling constant λ ~ 2. We conclude that H3S behaves as a strong-coupled orbital-limited superconductor over the entire range of temperatures and fields used for our measurements.