[Exploration and contemplation of homogenized education of specialists in pulmonary and critical care medicine at member hospitals of a hospital consortium].

Talent construction is the cornerstone to the establishment of a high-quality, homogeneous healthcare system in a healthcare consortium. Pulmonary and critical care medicine (PCCM) as the first pilot specialty, the standardized training of PCCM specialists has started and achieved remarkable results. The consortium member hospitals' physician specialist education is an important complement to PCCM training. The establishment of the consortium provides a new form of the education of physicians in PCCM, with the advantages of high quality teaching, wide coverage of staff and throughout the career development process. This article summarized the current status of physician specialty education in the member hospitals of the consortium, and further proposes the goal of homogenized specialty education for physicians in the member hospitals. And it analyzed in depth the problems that existed in the practice of training for hospital consortium member hospitals specialists, such as non-uniform level of instruction, non-systematic content of training, limited sources of teaching cases, and lack of teaching materials and equipment. For the medical consortium member hospital physician specialty education of in-depth thinking, we put forward the corresponding countermeasures. The aim of this study is to explore the homogenization of the specialty education system of pulmonary and critical care medicine in the member hospitals, in order to comprehensively improve the medical level of respiratory specialists in the member hospitals of the medical consortium.

Recent progress of TMD nanomaterials: phase transitions and applications.

Transition metal dichalcogenides (TMDs) show wide ranges of electronic properties ranging from semiconducting, semi-metallic to metallic due to their remarkable structural differences. To obtain 2D TMDs with specific properties, it is extremely important to develop particular strategies to obtain specific phase structures. Phase engineering is a traditional method to achieve transformation from one phase to another controllably. Control of such transformations enables the control of properties and access to a range of properties, otherwise inaccessible. Then extraordinary structural, electronic and optical properties lead to a broad range of potential applications. In this review, we introduce the various electronic properties of 2D TMDs and their polymorphs, and strategies and mechanisms for phase transitions, and phase transition kinetics. Moreover, the potential applications of 2D TMDs in energy storage and conversion, including electro/photocatalysts, batteries/supercapacitors and electronic devices, are also discussed. Finally, opportunities and challenges are highlighted. This review may further promote the development of TMD phase engineering and shed light on other two-dimensional materials of fundamental interest and with potential ranges of applications.

Adsorption of metal atoms on silicene: stability and quantum capacitance of silicene-based electrode materials.

We explore the adsorption stability and quantum capacitance of transition metal atoms on silicene based on first-principles calculations. Silicene with a buckled atomic layer has a high surface/volume ratio and silicene-based materials are expected to have potential applications for supercapacitors. We find that the most favorable adsorption sites on pristine silicene are valley sites for Al and Ti, and hollow sites for Ag, Cu and Au, respectively. Among all these systems with the doping of metal atoms, silicene is modulated to possess a quasi-metallic characteristic, accompanied by an appreciable electron transfer and the formation of defect states near the Fermi level. Due to the low density of states near the Fermi level, the quantum capacitance of pristine silicene has been limited. By the doping of metal atoms, especially Ti atoms, with the introduction of localized defect states near the Fermi level, quantum capacitance is found to be enhanced significantly. In addition, the quantum capacitance is found to increase monotonically following the increase of doping concentrations.

First principles study on 2H-1T' transition in MoS2 with copper.

The electronic properties of MoS2 are strongly controlled by the structure, providing a route to their modulation. We report, based on first principles calculations, that the adsorption of metal atom Cu on the surface can induce the phase transition of MoS2 from the semiconducting 2H to the metallic 1T' phase. Cu adsorption results in effective n-type doping of MoS2 by charge transfer from Cu in the case of the 1T' phase. This is distinct from the behavior in the 2H phase, where Cu does not donate any charge, and it is also distinct from alkali metal adsorption, where charge is donated to both 2H and 1T' MoS2. Charge donation to the 1T' phase by Cu stabilizes it with respect to the 2H structure and importantly, it also reduces the energy barrier between the 2H and 1T' structures. This difference reflects the higher electronegativity of Cu, which also indicates that Cu-modified MoS2 can be expected to be less chemically reactive than MoS2 with alkali metal adatoms. The main atomic mechanism of the structural transition is the gliding of S atoms on the upper surface. Finally, we report the energetics of the 2H to 1T' transition with several other adatoms, Ag, Au, Ni, Pt and Pd, but none of them are as effective as Cu in inducing the transition.

Superconductivity in HfTe5 across weak to strong topological insulator transition induced via pressures.

Recently, theoretical studies show that layered HfTe5 is at the boundary of weak &strong topological insulator (TI) and might crossover to a Dirac semimetal state by changing lattice parameters. The topological properties of 3D stacked HfTe5 are expected hence to be sensitive to pressures tuning. Here, we report pressure induced phase evolution in both electronic &crystal structures for HfTe5 with a culmination of pressure induced superconductivity. Our experiments indicated that the temperature for anomaly resistance peak (Tp) due to Lifshitz transition decreases first before climbs up to a maximum with pressure while the Tp minimum corresponds to the transition from a weak TI to strong TI. The HfTe5 crystal becomes superconductive above ~5.5 GPa where the Tp reaches maximum. The highest superconducting transition temperature (Tc) around 5 K was achieved at 20 GPa. Crystal structure studies indicate that HfTe5 transforms from a Cmcm phase across a monoclinic C2/m phase then to a P-1 phase with increasing pressure. Based on transport, structure studies a comprehensive phase diagram of HfTe5 is constructed as function of pressure. The work provides valuable experimental insights into the evolution on how to proceed from a weak TI precursor across a strong TI to superconductors.

Unifying miscellaneous performance criteria for a prototype supercapacitor via Co(OH)2 active material and current collector interactions.

The use of transition metal oxides and hydroxides in supercapacitors can yield high specific capacity electrodes. However, the effect of interaction between active material and current collector has remained unexplored. Here the behaviour of electrodeposited hexagonal cobalt hydroxide nanosheets on a variety of substrates was investigated, and the resulting valence bonding, morphological evolutions and phase transformations examined. It is shown that the electrochemical activity of the face centred cubic (FCC) Ni substrate dramatically decreases cyclability, the FCC Cu substrate also demonstrates decreased performance, and hexagonal carbon nanofibre (CNF) and Ti substrates exhibit far more stability. The miscellaneous roles of valence bonding, redox reactions and crystal structure mismatch between active material and current collector are examined, and their consequences discussed. Using the resulting insights into performance criteria, it was possible to select a suitable substrate for the fabrication of an asymmetric supercapacitor. The high performance and stability of the device demonstrates the usefulness of this approach, and the utility of applying these insights to energy storage devices.

Adsorption and diffusion of Li with S on pristine and defected graphene.

Li-S batteries are the promising high energy density alternative to current rechargeable battery technologies, particularly since it has been shown that the use of graphene, nanotubes and other nanostructured carbons in the cathode can improve the cyclability. We explore the microscopic interactions between LinS and graphene and diffusion of Li ions through pristine and defected graphene in the presence of S using first-principles methods. The introduction of Li weakens the interaction of atomic S with graphene, increasing the height of adsorbed S and leading to the formation of LinS clusters. These LinS clusters are adsorbed accompanied by charge transfer to the graphene. We find that double vacancies in the graphene are sufficient to allow Li ions to pass through the graphene plane. This is impeded in the presence of S due to the binding of Li to LinS clusters, but still can happen for larger clusters. The electronic properties confirm the excellent conductivity of pristine and defected graphene cathodes in contact with LinS clusters.

Inhibition of miR-23 protects myocardial function from ischemia-reperfusion injury through restoration of glutamine metabolism.

OBJECTIVE: Myocardial disorders caused by ischemia/reperfusion (IR) continue to be among the most frequent causes of debilitating disease and death. The contribution of cellular metabolism through the production of metabolic intermediates during IR has been increasingly investigated. MATERIALS AND METHODS: In this study, by using a rat IR injury model, we reported that the expression of microRNA miR-23 was induced by IR. In contrast, the glutamine metabolism was suppressed during IR. The glutamate, glutamine dehydrogenase activity, α-ketoglutarate, and glutaminase (GLS) mRNA expression were significantly decreased by IR. Moreover, the pretreatment of glutamine could protect the myocardium from IR injury. RESULTS: From microRNA target prediction analysis and results of luciferase assay, we found that miR-23 could directly target the 3'UTR of GLS. Finally, we demonstrated that inhibition of miR-23 protected myocardial function from IR through the restoration of glutamine metabolism. CONCLUSIONS: This study reveals that inhibition of miR-23 renders protective effects on rat IR injury, highlighting the importance of miR-23 and glutamine metabolism during IR, and suggests a potentially clinical benefit.

Design of Hydrogen Storage Alloys/Nanoporous Metals Hybrid Electrodes for Nickel-Metal Hydride Batteries.

Nickel metal hydride (Ni-MH) batteries have demonstrated key technology advantages for applications in new-energy vehicles, which play an important role in reducing greenhouse gas emissions and the world's dependence on fossil fuels. However, the poor high-rate dischargeability of the negative electrode materials-hydrogen storage alloys (HSAs) limits applications of Ni-MH batteries in high-power fields due to large polarization. Here we design a hybrid electrode by integrating HSAs with a current collector of three-dimensional bicontinuous nanoporous Ni. The electrode shows enhanced high-rate dischargeability with the capacity retention rate reaching 44.6% at a discharge current density of 3000 mA g(-1), which is 2.4 times that of bare HSAs (18.8%). Such a unique hybrid architecture not only enhances charge transfer between nanoporous Ni and HSAs, but also facilitates rapid diffusion of hydrogen atoms in HSAs. The developed HSAs/nanoporous metals hybrid structures exhibit great potential to be candidates as electrodes in high-performance Ni-MH batteries towards applications in new-energy vehicles.

Modulation of electronic properties from stacking orders and spin-orbit coupling for 3R-type MoS2.

Two-dimensional crystals stacked by van der Waals coupling, such as twisted graphene and coupled graphene-BN layers with unusual phenomena have been a focus of research recently. As a typical representative, with the modulation of structural symmetry, stacking orders and spin-orbit coupling, transitional metal dichalcogenides have shown a lot of fascinating properties. Here we reveal the effect of stacking orders with spin-orbit coupling on the electronic properties of few-layer 3R-type MoS2 by first principles methods. We analyze the splitting of states at the top of valence band and the bottom of conduction band, following the change of stacking order. We find that regardless of stacking orders and layers' number, the spin-up and spin-down channels are evidently separated and can be as a basis for the valley dependent spin polarization. With a model Hamiltonian about the layer's coupling, the band splitting can be effectively analyzed by the coupling parameters. It is found that the stacking sequences, such as abc and abca, have the stronger nearest-neighbor coupling which imply the popular of periodic abc stacking sequence in natural growth of MoS2.

Pressure evolution of the potential barriers of phase transition of MoS2, MoSe2 and MoTe2.

Two-dimensional crystals with weak layer interactions, such as twisted graphene, have been a focus of research recently. As a representative example, transitional metal dichalcogenides show a lot of fascinating properties due to stacking orders and spin-orbit coupling. We analyzed the dynamic energy barrier of possible phase transitions in MoX2 (X = S, Se and Te) with first-principles methods. In the structural transition from 2Hc to 2Ha, the energy barrier is found to be increased following an increase of pressure which is different from the phase transition in usual semiconductors. Among MoS2, MoSe2 and MoTe2, the energy barrier of MoS2 is the lowest and the stability of both 2Hc and 2Ha is reversed under pressure for MoS2. It is found that the absence of a phase transition in MoSe2 and MoTe2 is due to the competition between van der Waals interaction of layers and the coulomb interaction of Mo and X in nearest-neighbor layer of Mo in both phases.

Controlling phase transition for single-layer MTe2 (M = Mo and W): modulation of the potential barrier under strain.

Using first-principles DFT calculations, the pathway and the energy barrier of phase transition between 2H and 1T' have been investigated for MoTe2 and WTe2 monolayers. The Phase transition is controlled by the simultaneous movement of metal atoms and Te atoms in their plane without the intermediate phase 1T. The energy barrier (less than 0.9 eV per formula cell) is not so high that the phase transition is dynamically possible. The relative stability of both 2H and 1T' phases and the energy barrier for phase transition can be modulated by the biaxial and uniaxial strain. The dynamic energy barrier is decreased by applying the strain. The phase transition between 2H and 1T' controlled by the strain can be used to modulate the electronic properties of MoTe2 and WTe2.

Real-space observation of strong metal-support interaction: state-of-the-art and what's the next.

The real-space resolving of the encapsulated overlayer in the well-known model and industry catalysts, ascribed to the advent of dedicated transmission electron microscopy, enables us to probe novel nano/micro architecture chemistry for better application, revisiting our understanding of this key issue in heterogeneous catalysis. In this review, we summarize the latest progress of real-space observation of SMSI in several well-known systems mainly covered from the metal catalysts (mostly Pt) supported by the TiO2 , CeO2 and Fe3 O4 . As a comparison with the model catalyst Pt/Fe3 O4 , the industrial catalyst Cu/ZnO is also listed, followed with the suggested ongoing directions in the field.

Cu4 Cluster Doped Monolayer MoS2 for CO Oxidation.

The catalytic oxidation of CO molecule on a thermodynamically stable Cu4 cluster doped MoS2 monolayer is investigated by density functional theory (DFT) where the reaction proceeds in a new formation order of COOOCO* (O2* + 2CO* → COOOCO*), OCO* (COOOCO* → CO2 + OCO*), and CO2 (OCO* → CO2) desorption with the corresponding reaction barrier values of 0.220 eV, 0.370 eV and 0.119 eV, respectively. Therein, the rate-determining step is the second one. This low barrier indicates high activity of this system where CO oxidation could be realized at room temperature (even lower). As a result, the Cu4 doped MoS2 could be a candidate for CO oxidation with lower cost and higher activity without poisoning and corrosion problems.

Transformation of electronic properties and structural phase transition from HfN to Hf3N4.

We report investigation of the structural phase transition and electronic properties of Hf(1-x)N (0 ⩽ x ⩽ 0.25) using first principles calculations. The defective NaCl-type structure with Hf vacancies (V(Hf)) is found to be stable over a large phase region. Hf3N4 with the Zr3N4-type structure is only stable in relative small region and readily destabilized when the stoichiometric ratio of N to Hf deviates from 4/3. The electronic and optic properties of Hf(1-x)N are controlled by the concentration of V(Hf). The full depletion of excess free electrons from Hf atoms results in the structural phase transition of Hf3N4.

How important is the {103} plane of stable Ge2 Sb2 Te5 for phase-change memory?

Closely correlating with {200} plane of cubic phase, {103} plane of hexagonal phase of Ge(2)Sb(2)Te(5) plays a crucial role in achieving fast phase change process as well as formation of modulation structures, dislocations and twins in Ge(2)Sb(2)Te(5). The behaviors of {103} plane of hexagonal phase render the phase-change memory process as a nanoscale shape memory.

Structural stability of single-layer MoS2 under large strain.

Out-of-plane relaxation can introduce MoS(2) in flexible electronic/optoelectronic devices, while under larger strain it is possible to frustrate the structure of MoS(2). On the basis of first-principle calculations, the ideal tensile stress strain relations and failure mechanism of single-layer MoS(2) structure under large strain is investigated. The instability of phonon modes near the K point results in the decrease of tensile stress under large strain. The relative out-of-plane movement of Mo atoms is found to contribute to the mechanism of the soft phonon mode.

Toward structural/chemical cotailoring of phase-change Ge-Sb-Te in a transmission electron microscope.

Ge2Sb2Te5, as the prototype material for phase-change memory, can be transformed from amorphous phase into nanoscale rocksalt-type GeTe provided with an electron irradiation assisted by heating to 520°C in a 1250 kV transmission electron microscope. This sheds a new light into structural and chemical cotailoring of materials through coupling of thermal and electrical fields.

Gap openings in graphene regarding interfacial interaction from substrates.

Based on the size-dependent cohesive energy formula for two-dimensional materials, we investigate the gap openings in graphene layers regarding distinct interfacial interaction from substrates. Depending on the interfacial physicochemical nature, the gap is opened weakly induced by the van der Waals interaction but readily by the chemical bonding. Relative to the former, in essence, the distinct opening behavior for the latter comes from the substantial change in atomic cohesive energy of graphene associated with the coordination imperfection. Our predictions agree with the available experimental or computer simulation results for graphene layers on layered BN or bulk truncated SiC. The present work is of benefit for the application of graphene in electronics.

Enhanced hydrogen sensing properties of graphene by introducing a mono-atom-vacancy.

To facilitate the dissociative adsorption of H2 molecules on pristine graphene, the addition of a mono-atom-vacancy to graphene is proposed. This leads to reduction of the dissociative energy barrier for a H2 molecule on graphene from 3.097 to 0.805 eV for the first H2 and 0.869 eV for the second, according to first principles calculations. As a result, two H2 molecules can be easily dissociatively adsorbed on this defected graphene at room temperature. The electronic structure and conductivity of the graphene change significantly after H2 adsorption. In addition, the related dissociative adsorption phase diagrams under different temperatures and partial pressures show that this dissociative adsorption at room temperature is very sensitive (10(-35) mol L(-1)). Therefore, this defected graphene is promising for ultra-sensitive room temperature hydrogen sensing.