First-principles prediction of superconducting properties of monolayer 1T'-WS2 under biaxial tensile strain.

High-purity 1T'-WS2 film has been experimentally synthesized [Nature Materials, 20, 1113-1120 (2021)] and theoretically predicted to be a two-dimensional (2D) superconducting material with Dirac cones [arXiv:2301.11425]. In the present work, we further study the superconducting properties of monolayer 1T'-WS2 by applying biaxial tensile strain. It is shown that the superconducting critical temperature Tc firstly increases and then decreases with respect to tensile strains, with the highest superconducting critical temperature Tc of 7.25 K under the biaxial tensile strain of 3%. In particular, we find that Dirac cones also exist in several tensile strained cases. Our studies show that monolayer 1T'-WS2 may provide a good platform for understanding the superconductivity of 2D Dirac materials.

Right-to-Left Displacement of an Airgun Lead Bullet after Transorbital Entry into the Skull Complicated by Posttraumatic Epilepsy : A Case Report.

Penetrating head injury is a serious open cranial injury. In civilians, it is often caused by non-missile, low velocity flying objects that penetrate the skull through a weak cranial structure, forming intracranial foreign bodies. The intracranial foreign body can be displaced due to its special quality, shape, and location. In this paper, we report a rare case of right-to-left displacement of an airgun lead bullet after transorbital entry into the skull complicated by posttraumatic epilepsy, as a reminder to colleagues that intracranial metal foreign bodies maybe displaced intraoperatively. In addition, we have found that the presence of intracranial metallic foreign bodies may be a factor for the posttraumatic epilepsy, and their timely removal appears to be beneficial for epilepsy control.

Theoretical prediction of superconductivity in two-dimensional MXenes of molybdenum carbides.

Theoretically and experimentally, MXenes consisting of Mo and C have aroused much interest due to superconductivity in their films and even monolayer forms. Here, based on first-principles calculations, we systematically calculate the electronic structure, phonon dispersion, and electron-phonon coupling (EPC) of monolayer Mo2C (both T- and H-phases), Mo3C2, and Mo3C3. The results show that H-MoxCy (x = 2 or 3, y = 1-3) always have lower total energies than their corresponding T phase and other configurations. All these two-dimensional (2D) molybdenum carbides are metals and some of them display weak phonon-mediated superconductivity at different superconducting transition temperatures (Tc). The Mo 4d-orbitals play a critical role in their electronic properties and the Mo atomic vibrations play a dominant role in their low-frequency phonons, EPC, and superconductivity. By comparison, we find that increasing the Mo content can enhance the EPC and Tc. Besides, we further explore the impact of strain engineering on their superconducting related physical quantities. With increasing biaxial stretching, the phonon dispersions are gradually softened to form some soft modes, which can trigger some peaks of α2F(ω) in the low-frequency region and evidently increase the EPC λ. The Tc of H-Mo2C can be increased up to 11.79 K. Upon further biaxial stretching, charge density waves may appear in T-Mo2C, H-Mo3C2, and H-Mo3C3.

Experimental Determination of Hydrogen Isotope Transport Parameters in Vanadium.

Deuterium permeation through vanadium membranes in a wide range of pressures and the temperature range ~250-550 °C was experimentally investigated. Measurements on the same material were carried out in three laboratories with different features for an extended characterization and for cross-check validation. A unified equation for deuterium permeability in pure vanadium (99%) was provided as Φ=1.27×10-4·e-8667/T mol m-1 s-1 Pa-0.5, which represents a significant progress for the characterization of the transport properties in this material, given the spread of data, which can currently be found in the literature. Adsorption and recombination rate constants were also measured for hydrogen and deuterium at low pressure for the same range of temperatures. Finally, the influence of the surface roughness was examined by measuring samples with different surface finish.

Phonon-mediated superconductivity in two-dimensional hydrogenated phosphorus carbide: HPC3.

In recent years, three-dimensional (3D) high-temperature superconductors at ultrahigh pressure have been reported, typical examples are the polyhydrides H3S, LaH10, YH9, etc. To find high-temperature two-dimensional (2D) superconductors at atmospheric pressure is another research hotspot. Here, we investigated the possible superconductivity in a hydrogenated monolayer phosphorus carbide based on first-principles calculations. The results reveal that monolayer PC3 transforms from a semiconductor to a metal after hydrogenation. Interestingly, the C-π-bonding band contributes most to the states at the Fermi level. Based on the electron-phonon coupling mechanism, it is found that the electron-phonon coupling constant of HPC3 is 0.95, which mainly originates from the coupling of C-π electrons with the in-plane vibration modes of C and H. The calculated critical temperature Tc is 31.0 K, which is higher than those in most 2D superconductors. By further applying a biaxial tensile strain of 3%, the Tc can be boosted to 57.3 K, exceeding the McMillan limit. Thus, hydrogenation and strain are effective ways for increasing the superconducting Tc of 2D materials.

[Construction and identification of a vector inserted with gene of T7 RNA polymerase].

OBJECTIVE: To develop a system to rescue virus by intracellular expression of T7 RNA Polymerase. METHODS: The gene of T7 RNA Polymerase was amplified and cloned to VR1012 by molecular biological technology. The expression plasmid VR-1a was then identified. VR-1a and EV71 infectious plasmid were co-transfected in Vero cell. CPE was observed and viral gene viral antigen were detected. RESULTS: The gene of T7 RNA Polymerase was successfully cloned into vector VR1012. Vero cell developed to CPE after being transfected VR-1a and EV71 infectious plasmid. EV71 gene was amplified by RT-PCR from the culture. EV71 antigen was also detected by ELISA. CONCLUSION: The method can be used to rescue virus. It could apply to immunologic research of EV71 DNA vaccine.

[Construction of recombinant plasmid expressing S1 gene of new type of reovirus].

OBJECTIVE: To construct the recombinant plasmid containing S1 gene of new type of reovirus, and to study the expression of protein sigma1 in Vero cells. METHODS: The recombinant plasmid, named pC-S, was constructed by cloning S1 gene into vector pCAGGS/MCS. Then Vero cells were transfected with pC-S and collected at 24, 48, 72 h post transfection followed by SDS-PAGE and Western-Blot assay. RESULTS: Results both SDS-PAGE and Western-Blot assay indicated that sigma1 protein could be expressed well and the highest expression level was 72 h post transfection. CONCLUSIONS: Sigma1 protein could be expressed well in Vero cells by transfected with recombinant plasmid containing S1 gene, and could give some implications for subsequent research on virus-host interactions.