A way to identify whether a DFT gap is from right reasons or error cancellations: The case of copper chalcogenides.

Gap opening remains elusive in copper chalcogenides (Cu2X, X = S, Se, and Te), not least because Hubbard + U, hybrid functional, and GW methods have also failed. In this work, we elucidate that their failure originates from a severe underestimation of the 4s-3d orbital splitting of the Cu atom, which leads to a band-order inversion in the presence of an anionic crystal field. As a result, the Fermi energy is pinned due to symmetry, yielding an invariant zero gap. Utilizing the hybrid pseudopotentials to correct the underestimation on the atomic side opens up gaps of experimental magnitude in Cu2X, suggesting their predominantly electronic nature. Our work not only clarifies the debate about the Cu2X gap but also provides a way to identify which of the different methods really captures the physical essence and which is the result of error cancellation.

Evaluating the role of serum uric acid in the risk stratification and therapeutic response of patients with pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD).

Background: Pulmonary arterial hypertension (PAH) is a malignant pulmonary vascular disease that negatively impacts quality of life, exercise capacity, and mortality. This study sought to investigate the relationship between serum uric acid (UA) level and the disease severity and treatment response of patients with PAH and congenital heart disease (PAH-CHD). Methods: This study included 225 CHD patients and 40 healthy subjects. Serum UA was measured in all patients, and UA levels and haemodynamic parameters were re-evaluated in 20 patients who had received PAH-specific drug treatment for at least 7 ± 1 month. Results: Serum UA levels were significantly higher in PAH-CHD patients than in CHD patients with a normal pulmonary artery pressure and normal subjects (347.7 ± 105.7 µmol/L vs. 278.3 ± 84.6 µmol/L; 347.7 ± 105.7 µmol/L vs. 255.7 ± 44.5 µmol/L, p < 0.05). UA levels in the intermediate and high risk groups were significantly higher than those in the low-risk group (365.6 ± 107.8 µmol/L vs. 311.2 ± 82.8 µmol/L; 451.6 ± 117.6 µmol/L vs. 311.2 ± 82.8 µmol/L, p < 0.05). Serum UA levels positively correlated with mean pulmonary arterial pressure, WHO functional class, pulmonary vascular resistance, and NT-proBNP (r = 0.343, 0.357, 0.406, 0.398; p < 0.001), and negatively with mixed venous oxygen saturation (SvO2) and arterial oxygen saturation (SaO2) (r = -0.293, -0.329; p < 0.001). UA significantly decreased from 352.7 ± 97.5 to 294.4 ± 56.8 µmol/L (p = 0.001) after PAH-specific drug treatment for at least 6 months, along with significant decreases in mean pulmonary arterial pressure and pulmonary vascular resistance and increases in cardiac index and mixed SvO2. Conclusion: Serum UA can be used as a practical and economic biomarker for risk stratification and the evaluation of PAH-specific drug treatment effects for patients with PAH-CHD.

On the bandgap underestimation of delafossite transparent conductive oxides CuMO2 (M = Al, Ga and In): Role of pseudopotentials.

We report a first-principles study on the electronic and optical properties of delafossite CuMO2 (M = Al, Ga and In) using the recently developed hybrid functional pseudopotentials. We obtain trends of the fundamental and optical gaps with increasing M-atomic number, in agreement with experiment. In particular, we reproduce the experimental fundamental gap, optical gap, and Cu 3d energy of CuAlO2 almost perfectly, in contrast to the various calculations that have traditionally focused on valence electrons, which are unable to reproduce these key properties simultaneously. Since all that distinguishes our calculations is simply the use of a different Cu pseudopotential with a partially exact exchange interaction, this suggests that an inappropriate description of the electron-ion interaction may play a role in the density functional theory bandgap problem for CuAlO2. Applying Cu hybrid pseudopotentials to CuGaO2 and CuInO2 is also effective, yielding optical gaps that are very close to experiment. However, due to the limited experimental data for these two oxides, a comprehensive comparison as that for CuAlO2 is not possible. Furthermore, our calculations yield large exciton binding energies for delafossite CuMO2, all around 1 eV.

Liquid Metal-Doped Conductive Hydrogel for Construction of Multifunctional Sensors.

Interest in wearable and stretchable multifunctional sensors has grown rapidly in recent years. The sensing elements must accurately detect external stimuli to expand their applicability as sensors. However, the sensor's self-healing and adhesion to a target object have been major challenges in developing such practical and versatile devices. In this study, we prepared a hydrogel (LM-SA-PAA) composed of liquid metal (LM), sodium alginate (SA), and poly(acrylic acid) (PAA) with ultrastretchable, excellent self-healing, self-adhesive, and high-sensitivity sensing capabilities that enable the conformal contact between the sensor and skin even during dynamic movements. The excellent self-healing performance of the hydrogel stems from its double cross-linked networks, including physical and chemical cross-linked networks. The physical cross-link formed by the ionic interaction between the carboxyl groups of PAA and gallium ions provide the hydrogel with reversible autonomous repair properties, whereas the covalent bond provides the hydrogel with a stable and strong chemical network. Alginate forms a microgel shell around LM nanoparticles via the coordination of its carboxyl groups with Ga ions. In addition to offering exceptional colloidal stability, the alginate shell has sufficient polar groups, ensuring that the hydrogel adheres to diverse substrates. Based on the efficient electrical pathway provided by the LM, the hydrogel exhibited strain sensitivity and enabled the detection of various human motions and electrocardiographic monitoring. The preparation method is simple and versatile and can be used for the low-cost fabrication of multifunctional sensors, which have broad application prospects in human-machine interface compatibility and medical monitoring.

Verification and Analysis of Filter Paper-Based Intracellular Delivery of Exogenous Substances.

The intracellular delivery of exogenous substances is an essential technical means in the field of biomedical research, including cell therapy and gene editing. Although many delivery technologies and strategies are present, each technique has its own limitations. The delivery cost is usually a major limiting factor for general laboratories. In addition, simplifying the operation process and shortening the delivery time are key challenges. Here, we develop a filter paper-syringe (FPS) delivery method, a new type of cell permeation approach based on filter paper. The cells in a syringe are forced to pass through the filter paper quickly. During this process, external pressure forces the cells to collide and squeeze with the fiber matrix of the filter paper, causing the cells to deform rapidly, thereby enhancing the permeability of the cell membrane and realizing the delivery of exogenous substances. Moreover, the large gap between the fiber networks of filter paper can prevent the cells from bearing high pressure, thus maintaining high cell vitality. Results showed that the slow-speed filter paper used can realize efficient intracellular delivery of various exogenous substances, especially small molecular substances (e.g., 3-5 kDa dextran and siRNA). Meanwhile, we found that the FPS method not only does not require a lengthy operating step compared with the widely used liposomal delivery of siRNA but also that the delivery efficiency is similar. In conclusion, the FPS approach is a simple, easy-to-operate, and fast (about 2 s) delivery method and may be an attractive alternative to membrane destruction-based transfection.

Accuracy trade-off between one-electron and excitonic spectra of cuprous halides in first-principles calculations.

Because of the sophisticated error cancellation in the density functional theory (DFT)-based calculations, a theoretically more accurate input would not guarantee a better output. In this work, our first-principles GW plus Bethe-Salpeter equation calculations using pseudopotentials show that cuprous halides (CuCl and CuBr) are such extreme cases for which a better one-electron band is not accompanied with a better exciton binding energy. Moreover, we find that the exchange interaction of Cu core electrons plays a crucial role in their ground-state electronic properties, especially in the energy gap and macroscopic dielectric constant. Our work provides new insights into the understanding of the electronic structure of cuprous halides from the DFT perspective.

Expression of ApoA5 and its function in the right ventricular failing and remodeling secondary to pulmonary hypertension.

Right heart failure and right ventricular (RV) remodeling were the main reason for mortality of pulmonary hypertension (PH) patients. Apolipoprotein AV (ApoA5) is a key regulator of plasma triglyceride and have multifunction in several target organs. We detected decreased ApoA5 in serum of patients with PH and both in serum and RV of monocrotaline-induced PH model. Exogenously, overexpression ApoA5 by adenovirus showed protective effects on RV failure and RV fibrosis secondary to PH. In addition, in vitro experiments showed ApoA5 attenuated the activation of fibroblast induced by transforming growth factor ß1 and synthesis and secretion of extracellular matrix by inhibiting focal adhesion kinase-c-Jun N-terminal kinase-Smad3 pathway. Finally, we suggest that ApoA5 may potentially be a pivotal target for RV failure and fibrosis secondary of PH.

The Regional Differences in Game-Play Styles Considering Playing Position in the FIBA Female Continental Basketball Competitions.

The aim of this study was to identify regional differences based on playing position in terms of the technical performances among FIBA Female Continental Basketball Championships by controlling the influence of situational variables including the game outcome, game type, teams and opponent quality. The samples comprised of 9208 performance records from 471 games in the America, Africa, Asia and Europe Championships during 2013-2017 and were collected and analyzed by generalized mixed linear modeling. Our study highlighted that, although positional differences were clear among different continental championships, it is worth noting that African guards, forwards, and centers made more turnovers (TOV) compared with the corresponding positional players from other continental championships. In addition, European guards presented the lowest number of steals (STL) compared with African (ES = 0.28), Asian (ES = 0.21), and American guards (ES = 0.24). The results provide coaches to have a better understanding of game-play styles among FIBA Female Continental Basketball Competitions, which could optimize the development of female basketball and the selection and recruitment of female players at the international level.

Spin-Triplet Excitonic Insulator: The Case of Semihydrogenated Graphene.

While various excitonic insulators have been studied in the literature, due to the perceived too-small spin splitting, spin-triplet excitonic insulator is rare. In two-dimensional systems such as a semihydrogenated graphene (known as graphone), however, it is possible, as revealed by first-principles calculations coupled with Bethe-Salpeter equation. The critical temperature, given by an effective Hamiltonian, is 11.5 K. While detecting excitonic insulators is still a daunting challenge, the condensation of triplet excitons will result in spin superfluidity, which can be directly measured by a transport experiment. Nonlocal dielectric screening also leads to an unexpected phenomenon, namely, an indirect-to-direct transition crossover between single-particle band and exciton dispersion in the semihydrogenated graphene, which offers yet another test by experiment.

Core-shell MOF@MOF composites for sensitive nonenzymatic glucose sensing in human serum.

The detection of blood glucose level receives much attention, because diabetes has become one of the significant threats to human health worldwide. In this paper, we described a novel core-shell MOF@MOF composite-based electrochemical sensor for nonenzymatic glucose sensing in alkaline media. The core-shell UiO-67@Ni-MOF composites were synthesized by internal extended growth of shell Ni-MOF on the core UiO-67 under polyvinylpyrrolidone (PVP) regulation. In the sensor system, UiO-67 with large specific surface area and good conductivity was used to accelerate the rate of electron transfer of UiO-67@Ni-MOF. Ni-MOF served as an electrocatalytic material due to excellent electrochemical activity toward glucose oxidation. The morphology, structure, and electrochemical performance of UiO-67@Ni-MOF composites were characterized. To demonstrate the detection performance of the UiO-67@Ni-MOF composite-based sensor, it was successfully used for nonenzymatic glucose sensing. The results indicated that UiO-67@Ni-MOF composites exhibited high electrocatalytic activity toward glucose oxidation compared with individual UiO-67 and Ni-MOF. Moreover, the sensor possessed high sensitivity and selectivity for real-time amperometric detection of glucose. It performed glucose level detection in human serum samples with acceptable reliability and accuracy. The present work suggested that the as-fabricated sensor is promising for nonenzymatic glucose sensing in real samples and holds great potential as an alternative tool for the rapid diagnosis of diabetes and for monitoring blood glucose levels daily.

Explaining Positional Differences of Performance Profiles for the Elite Female Basketball Players.

The aim of the present study was to explore the differences in technical performances of players considering playing positions by controlling the effect of situational variables in each FIBA female continental basketball competition. Samples of 9,208 observations from 471 games in the America, Africa, Asia, and Europe Championships during 2013-2017 were collected and analyzed by generalized mixed linear modeling. The results showed that Centers from Europe had more 2-point made (ES = 0.69), 2-point attempted (ES = 0.79), and offensive (ES = 0.64) and defensive (ES = 0.48) rebounds than forward. Asian and European guards performed a fewer number of 2-point made (ES = 0.90; 0.91), 2-point attempted (ES = 1.06; 0.98), and offensive (ES = 1.30; 1.23) and defensive (ES = 0.93; 0.94) rebounds than Asian and European centers. African and Asian forward had more 2-point made (ES = 0.48; 0.50), 2-point attempted (ES = 0.50; 0.56) than guards. This study helps to better understand the technical demands of female basketball among different international competitions, which could pave a new way to analyze the development trend of female basketball and promoting specific training plans and game strategies for coaches and players.

Understanding the origin of bandgap problem in transition and post-transition metal oxides.

Improving electronic structure calculations for practical and technologically important materials has been a never-ending pursue. This is especially true for transition and post-transition metal oxides for which the current first-principles approaches still suffer various drawbacks. Here, we present a hierarchical-hybrid functional approach built on the use of pseudopotentials. The key is to introduce different amounts of exact exchange to core and valence electrons. It allows for treating the delocalization errors of sp and d electrons differently, which have been known to be an important source of error for the band structure. Using wurtzite ZnO as a prototype, we show that the approach is successful in simultaneously reproducing the bandgap and d-band position. Importantly, the same approach, without having to change the hybrid mixing parameters from those of Zn, works reasonably well for other binary 3d transition and post-transition metal oxides across board. Our findings thus point out a new direction of systematically improving the exchange functional in first-principles calculations.

Half-Excitonic Insulator: A Single-Spin Bose-Einstein Condensate.

First-principles calculations reveal an unusual electronic state (dubbed as half excitonic insulator) in monolayer 1T-MX_{2} (M=Co, Ni and X=Cl, Br). Its one spin channel has a many-body ground state due to excitonic instability, while the other is characterized by a conventional band insulator gap. This disparity arises from a competition between the band gap and exciton binding energy, which exhibits a spin dependence due to different orbital occupations. Such a state can be identified by optical absorption measurements and angle-resolved photoemission spectroscopy. Our theory not only provides new insights for the study of exciton condensation in magnetic materials but also suggests that strongly correlated materials could be fertile candidates for excitonic insulators.

High-Yield Formation of Graphdiyne Macrocycles through On-Surface Assembling and Coupling Reaction.

Rationally designed halogenated hydrocarbons are widely used building blocks to fabricate covalent-bonded carbon nanostructures on surfaces through a reaction pathway involving generation and dissociation of organometallic intermediates and irreversible covalent bond formation. Here, we provide a comprehensive picture of the on-surface-assisted homocoupling reaction of 1,3-bis(2-bromoethynyl)benzene on Au(111), aiming for the synthesis of graphdiyne nanostructures. Submolecular resolution scanning tunneling microscopy and noncontact atomic force microscopy observations identify the organometallic intermediates and their self-assemblies formed in the dehalogenation process. The demetallization of the organometallic intermediates at increased temperatures produces butadiyne moieties that spontaneously formed two different covalent structures ( i.e., graphdiyne zigzag chains and macrocycles), whose ratio was found to depend on the initial coverage of organometallic intermediates. At the optimal condition, the stepwise demetallization and cyclization led to a high-yield production of graphdiyne macrocycles up to 95%. Statistical analysis and theoretical calculations suggested that the favored formation of macrocycles resulted from the complex interplay between thermodynamic and kinetic processes involving the organometallic bonded intermediates and the covalently bonded butadiyne moieties.

Effect of Hartree-Fock pseudopotentials on local density functional theory calculations.

Density functional theory (DFT) can run into serious difficulties with localized states in elements such as transition metals with occupied d states and oxygen. In contrast, including a fraction of the Hartree-Fock exchange can be a better approach for such localized states. Here, we develop Hartree-Fock pseudopotentials to be used alongside DFT for solids. The computational cost is on a par with standard DFT. Calculations for a range of II-VI, III-V and group-IV semiconductors with diverse physical properties show an observably improved band gap for systems containing d-electrons, pointing to a new direction in electronic theory.

Unique Transformation from Graphene to Carbide on Re(0001) Induced by Strong Carbon-Metal Interaction.

During graphene growth on various transition metals in the periodic table, metal carbides always emerge to behave as complex intermediates. On VIII metals, metastable carbides usually evolve and then transform into graphene along the phase interfaces, and even no metal carbides can form on IB-IIB metals. In contrast, during graphene growth on group IVB-VIB metals, carbides are usually generated even before the evolution of graphene and stably exist throughout the whole growth process. However, for the remaining transition metals, e.g., group VIIB, located in between IVB-VIB and VIII, the interplay between graphene and carbide is still vague. Herein, on Re(0001) (VIIB), we have revealed a novel transition from graphene to metal carbide (reverse to that on VIII metals) for the first time. This transition experienced graphene decomposition, dissolution, and carbon segregation processes, as evidenced by scanning tunneling microscopy (STM) and on-site, variable-temperature low electron energy diffraction (LEED) characterizations. This work thus completes the picture about the interplay between graphene and carbide on/in transition metals in the periodic table, as well as discloses a new territory for the growth of carbon-related materials, especially the metal carbide.

Two-dimensional metallic tantalum disulfide as a hydrogen evolution catalyst.

Two-dimensional metallic transition metal dichalcogenides are emerging as prototypes for uncovering fundamental physical phenomena, such as superconductivity and charge-density waves, as well as for engineering-related applications. However, the batch production of such envisioned transition metal dichalcogenides remains challenging, which has hindered the aforementioned explorations. Herein, we fabricate thickness-tunable tantalum disulfide flakes and centimetre-sized ultrathin films on an electrode material of gold foil via a facile chemical vapour deposition route. Through temperature-dependent Raman characterization, we observe the transition from nearly commensurate to commensurate charge-density wave phases with our ultrathin tantalum disulfide flakes. We have obtained high hydrogen evolution reaction efficiency with the as-grown tantalum disulfide flakes directly synthesized on gold foils comparable to traditional platinum catalysts. This work could promote further efforts for exploring new efficient catalysts in the large materials family of metallic transition metal dichalcogenides, as well as exploiting their applications towards more versatile applications.Metallic transition metal dichalcogenides are important materials for catalysis, but scalable and controllable preparation methods are scarce. Here, the authors synthesize 2H-TaS2 as centimetre-scale films of tunable thickness and show they are an efficient catalyst for hydrogen evolution.

Temperature-Triggered Sulfur Vacancy Evolution in Monolayer MoS2 /Graphene Heterostructures.

The existence of defects in 2D semiconductors has been predicted to generate unique physical properties and markedly influence their electronic and optoelectronic properties. In this work, it is found that the monolayer MoS2 prepared by chemical vapor deposition is nearly defect-free after annealing under ultrahigh vacuum conditions at ≈400 K, as evidenced by scanning tunneling microscopy observations. However, after thermal annealing process at ≈900 K, the existence of dominant single sulfur vacancies and relatively rare vacancy chains (2S, 3S, and 4S) is convinced in monolayer MoS2 as-grown on Au foils. Of particular significance is the revelation that the versatile vacancies can modulate the band structure of the monolayer MoS2 , leading to a decrease of the bandgap and an obvious n-doping effect. These results are confirmed by scanning tunneling spectroscopy data as well as first-principles theoretical simulations of the related morphologies and the electronic properties of the various defect types. Briefly, this work should pave a novel route for defect engineering and hence the electronic property modulation of three-atom-thin 2D layered semiconductors.

Scaling Universality between Band Gap and Exciton Binding Energy of Two-Dimensional Semiconductors.

Using first-principles GW Bethe-Salpeter equation calculations and the k·p theory, we unambiguously show that for two-dimensional (2D) semiconductors, there exists a robust linear scaling law between the quasiparticle band gap (E_{g}) and the exciton binding energy (E_{b}), namely, E_{b}≈E_{g}/4, regardless of their lattice configuration, bonding characteristic, as well as the topological property. Such a parameter-free universality is never observed in their three-dimensional counterparts. By deriving a simple expression for the 2D polarizability merely with respect to E_{g}, and adopting the screened hydrogen model for E_{b}, the linear scaling law can be deduced analytically. This work provides an opportunity to better understand the fantastic consequence of the 2D nature for materials, and thus offers valuable guidance for their property modulation and performance control.

Irreparable Defects Produced by the Patching of h-BN Frontiers on Strongly Interacting Re(0001) and Their Electronic Properties.

Clarifying the origin and the electronic properties of defects in materials is crucial since the mechanical, electronic and magnetic properties can be tuned by defects. Herein, we find that, for the growth of h-BN monolayer on Re(0001), the patching frontiers of different domains can be classified into three types, i.e., the patching of B- and N-terminated (B|N-terminated) frontiers, B|B-terminated frontiers and N|N-terminated frontiers, which introduce three types of defects, i.e., the "heart" shaped moiré-level defect, the nonbonded and bonded line defects, respectively. These defects were found to bring significant modulations to the electronic properties of h-BN, by introducing band gap reductions and in-gap states, comparing with perfect h-BN on Re(0001) with a band gap of ∼3.7 eV. The intrinsic binary composition nature of h-BN and the strong h-BN-Re(0001) interaction are proposed to be cooperatively responsible for the formation of these three types of defects. The former one provides different types of h-BN frontiers for domain patching. And the later one induces multinucleation but aligned growth of h-BN domains on Re(0001), thus precluding their subsequent coalescence to some extent. This work offers a deep insight into the categories of defects introduced from the patching growth of two-dimensional layered materials, as well as their electronic property modulation through the defect engineering.