Superconductivity in the cuprate superconductors and the Fe-based superconductors is realized by doping the parent compound with charge carriers, or by application of high pressure, to suppress the antiferromagnetic state. Such a rich phase diagram is important in understanding superconductivity mechanism and other physics in the Cu-and Fe-based high temperature superconductors.In this paper, we report a phase diagram in the single-layer FeSe films grown on SrTiO 3 substrate by an annealing procedure to tune the charge carrier concentration over a wide range. A dramatic change of the band structure and Fermi surface is observed, with two distinct phases identified that are competing during the annealing process. Superconductivity with a record high transition temperature (T c ) at 65±5 K is realized by optimizing the annealing process. The wide tunability of the system across different phases, and its high-T c , make the single-layer FeSe film ideal not only to investigate the superconductivity physics and mechanism, but also to study novel quantum phenomena and for potential applications.

The concept of ligand bias at G protein-coupled receptors broadens the possibilities for agonist activities and provides the opportunity to develop safer, more selective therapeutics. Morphine pharmacology in b-arrestin-2 knockout mice suggested that a ligand that promotes coupling of the m-opioid receptor (MOR) to G proteins, but not b-arrestins, would result in higher analgesic efficacy, less gastrointestinal dysfunction, and less respiratory suppression than morphine. Here we report the discovery of TRV130 ([(3-methoxythiophen-2-yl)methyl]({2-[(9R)-9-(pyridin-2-yl)-6-oxaspiro[4.5]decan-9-yl]ethyl})amine), a novel MOR G protein-biased ligand. In cell-based assays, TRV130 elicits robust G protein signaling, with potency and efficacy similar to morphine, but with far less b-arrestin recruitment and receptor internalization. In mice and rats, TRV130 is potently analgesic while causing less gastrointestinal dysfunction and respiratory suppression than morphine at equianalgesic doses. TRV130 successfully translates evidence that analgesic and adverse MOR signaling pathways are distinct into a biased ligand with differentiated pharmacology. These preclinical data suggest that TRV130 may be a safer and more tolerable therapeutic for treating severe pain.

The recent discovery of high-temperature superconductivity in iron-based compounds has attracted much attention . How to further increase the superconducting transition temperature ( T c ) and how to understand the superconductivity mechanism are two prominent issues facing the current study of iron-based superconductors. The latest report of high-T c superconductivity in a single-layer FeSe is therefore both surprising and signifi cant. Here we present investigations of the electronic structure and superconducting gap of the single-layer FeSe superconductor. Its Fermi surface is distinct from other iron-based superconductors, consisting only of electron-like pockets near the zone corner without indication of any Fermi surface around the zone centre. Nearly isotropic superconducting gap is observed in this strictly two-dimensional system. The temperature dependence of the superconducting gap gives a transition temperature T c ~ 55 K. These results have established a clear case that such a simple electronic structure is compatible with high-T c superconductivity in iron-based superconductors.

A new strategy for dramatically amplifying enzyme-linked electrical detection of proteins and DNA using carbon nanotubes (CNTs) for carrying numerous enzyme tracers and accumulating the enzymatically liberated product on CNT-modified transducer is described. Such a CNT-derived double-step amplification pathway (of both the recognition and transduction events) allows the detection of DNA and proteins down to 1.3 and 160 zmol, respectively, in 25-50 muL samples and indicates great promise for PCR-free DNA analysis. The new protocol is illustrated for monitoring sandwich hybridization and antibody-antigen interactions in connection with alkaline-phosphatase tracers. The DNA-linking of CNTs and particles holds promise also for assembling hybrid nanostructures relevant to molecular electronic devices.

Large scale epitaxial growth and transfer of monolayer MoS has attracted great attention in recent years. Here, we report the wafer-scale epitaxial growth of highly oriented continuous and uniform monolayer MoS films on single-crystalline sapphire wafers by chemical vapor deposition (CVD) method. The epitaxial film is of high quality and stitched by many 0°, 60° domains and 60°-domain boundaries. Moreover, such wafer-scale monolayer MoS films can be transferred and stacked by a simple stamp-transfer process, and the substrate is reusable for subsequent growth. Our progress would facilitate the scalable fabrication of various electronic, valleytronic, and optoelectronic devices for practical applications.

Nucleic-acid hybridization assays based on the use of different inorganic-colloid (quantum dots) nanocrystal tracers for the simultaneous electrochemical measurements of multiple DNA targets are described. Three encoding nanoparticles (zinc sulfide, cadmium sulfide, and lead sulfide) are used to differentiate the signals of three DNA targets in connection to stripping-voltammetric measurements of the heavy metal dissolution products. These products yield well-defined and resolved stripping peaks at -1.12 V (Zn), -0.68 V (Cd), and -0.53 V (Pb) at the mercury-coated glassy-carbon electrode (vs Ag/AgCl reference). The position and size of these peaks reflect the identity and level of the corresponding DNA target. The multi-target detection capability is coupled to the amplification feature of stripping voltammetry (to yield femtomole detection limits) and with an efficient magnetic removal of nonhybridized nucleic acids to offer high sensitivity and selectivity. The protocol is illustrated for the simultaneous detection of three DNA sequences related to the BCRA1 breast-cancer gene in a single sample in connection to magnetic beads bearing the corresponding oligonucleotide probes. The new electrochemical coding is expected to bring new capabilities for DNA diagnostics, and for bioanalysis, in general.

The development of efficient artificial photocatalysts and photoelectrocatalysts for the reduction of CO2 with H2O to fuels and chemicals has attracted much attention in recent years. Although the state-of-the-art for the production of fuels or chemicals from CO2 using solar energy is still far from practical consideration, rich knowledge has been accumulated to understand the key factors that determine the catalytic performances. This Feature article highlights recent advances in the photocatalytic and photoelectrocatalytic reduction of CO2 with H2O using heterogeneous semiconductor-based catalysts. The effects of structural aspects of semiconductors, such as crystalline phases, particle sizes, morphologies, exposed facets and heterojunctions, on their catalytic behaviours are discussed. The roles of different types of cocatalysts and the impact of their nanostructures on surface CO2 chemisorption and reduction are also analysed. The present article aims to provide insights into the rational design of efficient heterogeneous catalysts with controlled nanostructures for the photocatalytic and photoelectrocatalytic reduction of CO2 with H2O.

Two-dimensional materials provide extraordinary opportunities for exploring phenomena arising in atomically thin crystals. Beginning with the first isolation of graphene, mechanical exfoliation has been a key to provide high-quality two-dimensional materials, but despite improvements it is still limited in yield, lateral size and contamination. Here we introduce a contamination-free, one-step and universal Au-assisted mechanical exfoliation method and demonstrate its effectiveness by isolating 40 types of single-crystalline monolayers, including elemental two-dimensional crystals, metal-dichalcogenides, magnets and superconductors. Most of them are of millimeter-size and high-quality, as shown by transfer-free measurements of electron microscopy, photo spectroscopies and electrical transport. Large suspended two-dimensional crystals and heterojunctions were also prepared with high-yield. Enhanced adhesion between the crystals and the substrates enables such efficient exfoliation, for which we identify a gold-assisted exfoliation method that underpins a universal route for producing large-area monolayers and thus supports studies of fundamental properties and potential application of two-dimensional materials.