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1.
Phys Chem Chem Phys ; 26(21): 15539-15546, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38756083

ABSTRACT

Spin current generation from charge current in nonmagnetic materials promises an energy-efficient scheme for manipulating magnetization in spintronic devices. In some asymmetric two-dimensional (2D) materials, the Rashba and valley effects coexist owing to strong spin-orbit coupling (SOC), which induces the spin Hall effect due to spin-momentum locking of both effects. Herein, we propose a new Janus structure MoSiAs2Se with both valley physics and the Rashba effect and reveal an effective way to modulate the properties of this structure. The results demonstrated that applying an external electric field is an effective means to modulating the electronic properties of MoSiAs2Se, leading to both type I-II phase transitions and semiconductor-metal phase transitions. Furthermore, the coexistence of the Rashba and valley effects in monolayer MoSiAs2Se contributes to the spin Hall effect (SHE). The magnitude and direction of spin Hall conductivity can also be manipulated with an out-of-plane electric field. Our results enrich the physics and materials of the Rashba and valley systems, opening new opportunities for the applications of 2D Janus materials in spintronic devices.

2.
J Phys Condens Matter ; 36(33)2024 May 22.
Article in English | MEDLINE | ID: mdl-38729179

ABSTRACT

Modulation of the electronic structure has played a crucial role in advancing the field of two-dimensional materials, but there are still many unexplored directions, such as the twist angle for a novel degree of freedom, for modulating the properties of heterostructures. We observed a distinct pattern in the energy bands of bilayer bismuthene, demonstrating that modulating the twist angle and interlayer spacing significantly influences interlayer interactions. Our study of various interlayer spacings and twist angles revealed a close relationship between bandgap size and interlayer spacing, while the twist angle notably affects the shape of the energy bands. Furthermore, we observed a synergistic effect between these two factors. As the twist angle decreases, the energy bands become flat, and flat bands can be generated without requiring a specific angle on bilayer bismuthene. Our results suggest a promising way to tailor the energy band structure of bilayer 2D materials by varying the interlayer spacing and twist angle.

3.
Inorg Chem ; 63(9): 4279-4287, 2024 Mar 04.
Article in English | MEDLINE | ID: mdl-38377593

ABSTRACT

It is highly desirable but challenging to optimize the electronic structure of an active site to realize moderate active site-Hads bond energies for boosting photocatalytic H2 evolution. Herein, an interfacial engineering strategy is developed to simultaneously concentrate hydrogen species and accelerate the combination of an Hads intermediate to generate free H2 by constructing W-WC-W2C (WCC) cocatalysts. Systematic investigations reveal that hybridizing with W2C creates electron-rich W active sites and effectively induces the downshift of the d-band center of W in WC. Consequently, the strong W-Hads bonds on the surface of WC are weakened, thus promoting the desorption of Hads to rapidly produce free H2. The optimized 40-WCC/CdS photocatalyst exhibits a high hydrogen evolution rate of 63.6 mmol g-1 h-1 under visible light (≥420 nm) with an apparent quantum efficiency of 39.5% at 425 nm monochromatic light, which is about 40-fold of the pristine CdS. This work offers insights into the design of cocatalyst for high-efficiency photocatalytic H2 production.

4.
Nano Lett ; 24(7): 2415-2420, 2024 Feb 21.
Article in English | MEDLINE | ID: mdl-38323579

ABSTRACT

Electrostatic gating has emerged as a powerful technique for tailoring the magnetic properties of two-dimensional (2D) magnets, offering exciting prospects including enhancement of magnetic anisotropy, boosting Curie temperature, and strengthening exchange coupling effects. Here, we focus on electrical control of the ferromagnetic resonance of the quasi-2D Kagome magnet Cu(1,3-bdc). By harnessing an electrostatic field through ionic liquid gating, significant shifts are observed in the ferromagnetic resonance field in both out-of-plane and in-plane measurements. Moreover, the effective magnetization and gyromagnetic ratios display voltage-dependent variations. A closer examination reveals that the voltage-induced changes can modulate magnetocrystalline anisotropy by several hundred gauss, while the impact on orbital magnetization remains relatively subtle. Density functional theory (DFT) calculations reveal varying d-orbital hybridizations at different voltages. This research unveils intricate physics within the Kagome lattice magnet and further underscores the potential of electrostatic manipulation in steering magnetism with promising implications for the development of spintronic devices.

5.
Phys Rev Lett ; 131(9): 096902, 2023 Sep 01.
Article in English | MEDLINE | ID: mdl-37721822

ABSTRACT

In mirror-symmetric systems, there is a possibility of the realization of extended gapless electronic states characterized as nodal lines or rings. Strain induced modifications to these states lead to the emergence of different classes of nodal rings with qualitatively different physical properties. Here we study optical response and the electromagnetic wave propagation in type I nodal ring semimetals, in which the low-energy quasiparticle dispersion is parabolic in momentum k_{x} and k_{y} and is linear in k_{z}. This leads to a highly anisotropic dielectric permittivity tensor in which the optical response is plasmonic in one spatial direction and dielectric in the other two directions. The resulting normal modes (polaritons) in the bulk material become hyperbolic over a broad frequency range, which is furthermore tunable by the doping level. The propagation, reflection, and polarization properties of the hyperbolic polaritons not only provide valuable information about the electronic structure of these fascinating materials in the most interesting region near the nodal rings but also pave the way to tunable hyperbolic materials with applications ranging from anomalous refraction and waveguiding to perfect absorption in ultrathin subwavelength films.

6.
Phys Chem Chem Phys ; 25(28): 19239-19244, 2023 Jul 19.
Article in English | MEDLINE | ID: mdl-37431775

ABSTRACT

A novel two-dimensional carbon allotrope has been proposed using density functional theory (DFT) calculations. The cell contains 24 carbon atoms and is composed of five-, six-, and seven-membered rings, named LC567. It is low in energy and has excellent dynamic, thermal, and mechanical stability. Our results demonstrate that the theoretical capacity of monolayer LC567 is up to 1117 mA h g-1, and the lithium diffusion barrier is also very low, around 0.18 eV, which is superior to graphene and most reported two-dimensional anode materials. In addition, LC567 exhibits quite low open circuit voltage during the process of Li ion insertion. For the bulk of LC567, it still exhibits high capacity and ideal open circuit voltage, revealing its potential application as an anode for lithium batteries. Meanwhile, we discuss the mechanism of the high capacity and low diffusion barrier of LC567 as an anode material for lithium batteries, and find that the high capacity and low diffusion barrier properties may be related to the pentagonal carbon rings (C5).

7.
Nanoscale ; 15(19): 8825-8831, 2023 May 18.
Article in English | MEDLINE | ID: mdl-37114430

ABSTRACT

Most special two-dimensional (2D) lattices, such as Kagome and Lieb lattices, can only generate a single flat band. Here, we propose a 2D lattice named a quadrangular-star lattice (QSL). It can produce coupling double flat bands, which indicates that there exists stronger electronic correlation than in the systems with only one flat band. Moreover, we suggest some 2D carbon allotropes (e.g. CQSL-12 and CQSL-20), made of carbon rings and dimers, to realize QSL in real materials. By calculating the band structures of the carbon materials, we find that there are indeed two coupling flat bands around the Fermi level. Hole doping leads to strong magnetism of the carbon materials. When the two flat bands are half filled, i.e., in the cases of one- and three-hole doping, the magnetic momentums mainly distribute on the atoms of the carbon rings and dimers, respectively. Even in the case of two-hole doping, the carbon structure also shows ferromagnetic characteristics, and the total magnetic moments are larger than the former two cases.

8.
RSC Adv ; 13(14): 9624-9635, 2023 Mar 20.
Article in English | MEDLINE | ID: mdl-36968037

ABSTRACT

Vertical stacking of two-dimensional materials into layered van der Waals heterostructures is considered favourable for nanoelectronics and thermoelectric applications. In this work, we investigate the structural, electronic and thermoelectric properties of GeC and Janus monolayers MXO (M = Ti, Zr; X = S, Se) and their van der Waals (vdW) heterostructures using first-principles calculations. The values of binding energies, interlayer distances and thermal stability confirm the stability of these vdW heterostructures. The calculated band structure shows that GeC monolayer have a direct band gap while MXO (M = Ti, Zr; X = S, Se) and their van der Waals heterostructures show indirect band nature. Partial density of states confirms the type-II band alignment of GeC-MXY vdW heterostructures. Our results shows that ZrSeO (GeC) monolayers and GeC-ZrSO vdW heterostructures have higher power factor, making them promising for thermoelectric device applications.

9.
Medicine (Baltimore) ; 101(46): e31911, 2022 Nov 18.
Article in English | MEDLINE | ID: mdl-36401434

ABSTRACT

Adjuvant endocrine therapy (AET) is known to reduce the risk of hormone receptor-positive (HR+) breast cancer (BC) recurrence and mortality rates, but its impact on cardiovascular disease (CVD) events is unclear. The primary objective of this study was to analyze the association of HR status with CVD mortality in patients with stage I to III BC. A retrospective study of patients with stage I to III BC was conducted using the 2004 to 2016 Surveillance, Epidemiology, and End Results (SEER) database, and patients were grouped according to their HR status. Propensity score matching (PSM) was used to adjust for heterogeneity between the groups. The cumulative incidence rate of CVD mortality was evaluated via a cumulative incidence curve. Univariate and multivariate Fine and Gray's competing risk regression models were used to identify risk factors associated with CVD mortality. In total, 399,209 patients with BC were included in this study, and 329,958 patients (82.65%) were HR-positive. The cumulative incidence of CVD death was 8.28% in stage I to III BC patients. In the constituent ratio analysis, primary BC was the leading cause of death (45.29%, N = 31,465), followed by heart disease (16.07%, N = 11,166). Compared to the second year following BC diagnosis, the risk of CVD-specific death gradually increased. After PSM, 65,952 pairs of patients were matched, which led to the equilibrium of all variables between the HR-negative cohort and HR+ cohort. Multivariate analysis indicated that HR status was not significantly associated with the risk of CVD mortality, with a hazard ratio of 1.01 (P = .895). This study highlights the importance of understanding the associations between risk factors and CVD for BC patients. HR status was not associated with the risk of CVD mortality in this study.


Subject(s)
Breast Neoplasms , Cardiovascular Diseases , Humans , Female , Retrospective Studies , Neoplasm Recurrence, Local/complications , Hormones
10.
J Phys Condens Matter ; 35(5)2022 Dec 14.
Article in English | MEDLINE | ID: mdl-36410037

ABSTRACT

We establish a non-Bloch band theory for one-dimensional(1D) non-Hermitian topological superconductors. The universal physical properties of non-Hermitian topological superconductors are revealed based on the theory. According to the particle-hole symmetry, there exist reciprocal particle and hole loops of generalized Brillouin zone. The critical point of quantum phase transition, where the energy gap closes, appears when the particle and hole loops intersect at Bloch points. If the non-Hermitian system has non-Hermitian skin effects, the non-Hermitian skin effect should be theZ2skin effect: the corresponding eigenstates of particle and hole localize at opposite ends of an open chain, respectively. The non-Bloch band theory is applied to two examples, non-Hermitianp- ands-wave topological superconductors. In terms of Majorana Pfaffian, aZ2non-Bloch topological invariant is defined to establish the non-Hermitian bulk-boundary correspondence for the non-Hermitian topological superconductors.

11.
Nanoscale ; 14(24): 8797-8805, 2022 Jun 23.
Article in English | MEDLINE | ID: mdl-35678526

ABSTRACT

7-Atomic-layer materials have attracted much attention recently because of their rich structures and more-abundant properties than 3- and 5-atomic-layer materials. However, the thermoelectric properties of the new monolayer materials have not been explored yet. Here, we investigate the thermoelectric conversion efficiency of a 7-atomic-layer structure ZrGe2N4, which is selected from a series of 7-atomic-layer structures according to their stabilities and thermoelectric properties. The results indicate that this material is an excellent candidate for high-performance thermoelectric materials. Its figure of merit ZT value is close to 4.0 at high temperature. The high efficiency originates from two factors: one is the lower thermal conductivity of ZrGe2N4 and the other is the decoupling of electron and phonon transport in the 7-atomic-layer structures.

12.
Environ Geochem Health ; 44(10): 3527-3539, 2022 Oct.
Article in English | MEDLINE | ID: mdl-34625866

ABSTRACT

This study investigated the environmental geochemical characteristics of rare-earth elements (REEs) in surface waters in the Huainan mining area, Anhui Province, China. The REEs concentrations were determined by ICP-MS, and the inorganic species of dissolved REEs in the river and coal mining subsidence area water samples were calculated by using the Visual MINTEQ (version 3.1) code. On this basis, the distribution and geochemical characteristics of REEs in the surface waters were systematically analyzed, and the main inorganic species of REEs were investigated. The results showed the following: (1) The REEs concentrations in the surface waters were relatively low, ranging from 0.1361 to 0.3536 µg/L, and the average ∑REEs concentration was 0.2062 µg/L. Compared with light rare-earth elements (LREEs), heavy rare-earth elements (HREEs) were significantly enriched, with an average enrichment factor of 1.4642. Due to the interaction of high pH values and high cation concentrations, the ∑REEs content in the subsidence area water was significantly lower than that in the river water. (2) The distribution pattern of REEs in the surface waters normalized against the North American Shale Composite (NASC) showed that the REEs in the study area had different degrees of cerium (Ce) and europium (Eu) anomalies. The negative Ce anomalies were probably closely related to the pH conditions, whereas the positive Eu anomalies were mainly attributed to preferential chemical weathering and the dissolution of feldspar minerals. (3) The simulation results obtained by using Visual MINTEQ code showed that the dominant and typically inorganic complex form of REEs in the surface waters was carbonate complexes, and this form was one of the reasons for the enrichment of HREEs in the surface water.


Subject(s)
Cerium , Coal Mining , Metals, Rare Earth , China , Environmental Monitoring/methods , Europium , Metals, Rare Earth/analysis , Mining , Water
13.
Nanotechnology ; 32(48)2021 Sep 06.
Article in English | MEDLINE | ID: mdl-34380128

ABSTRACT

By means of quotient-graph associated crystal prediction method, a new graphyne allotrope with unique Dirac nodal grid state is reported in this work. It is named as 191-E24Y24-1 according to its hexagonal lattice (with P6/mmm symmetry, No. 191) containing 24 sp2-hybridized carbon atoms and 24 sp-hybridized ones. The first-principles results show that the total energy of 191-E24Y24-1 is more favorable than that of recent synthesizedß-graphdiyne and carbon ene-yne. It is also demonstrated to be dynamically, thermally, and mechanically stable. Interestingly, the 191-E24Y24-1 harbors intrinsic semimetal features showing intriguing hexagonal Dirac nodal grid state in the reciprocal space. Such unique electronic state is stable against small external tensile strains, and it is tunable under compression strains which will transform to new triangle Dirac nodal grid state. Moreover, a new metastable graphyne allotrope named 191-E12Y36-4 with Dirac nodal loop state is also observed in the process of stretching 191-E24Y24-1 with large tensile strains. The results presented in this work reveal two novel graphyne allotropes with exotic electronic properties. These discoveries are not only physical interesting, but also provide potential material candidates for carbon-based high performance electronic nanodevices.

14.
Neoplasma ; 68(1): 71-78, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33030958

ABSTRACT

Highly expressed high mobility group box-1 protein (HMGB1) promotes tumor metastasis. Whether HMGB1 participates in breast cancer cell activation of fibroblasts is unknown. The culture medium of 6 breast cancer cell lines with different migration potential, and with HMGB1 overexpression or knockdown was used to induce fibroblast activation, and collagen and α-SMA expression were measured. We evaluated the migration potential of MDA-MB-231 cells with fibroblasts treated with 3-PO (3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one) inhibitor, anti-HMGB1 treatment, or RAGE (receptor for advanced glycation end products) knockdown. A lung metastasis murine model was used to evaluate whether the RAGE-knockdown fibroblasts mitigates MDA-MB-231 metastasis. Breast cancer cells that are highly migratory and have a high invasive potential, had higher HMGB1 expression and induced greater fibroblast activation strongly than cells with poorer motility. hrHMGB1 and the supernatants of HMGB1-overexpressed MCF-7 cells promoted fibroblast activation, but loss-HMGB1 of MDA-MB-231 abolished potential. Moreover, a novel mechanism was identified by which HMGB1 facilitated fibroblast activation by RAGE/aerobic glycolysis. Consistently, fibroblasts enhanced MDA-MB-231 metastasis, but the enhancement was reversed by 3-PO inhibition, anti-HMGB1 treatment, or RAGE knockdown in vitro and in vivo. We identified that HMGB1 secreted by breast cancer cells promotes fibroblast activation via RAGE/aerobic glycolysis, and activated fibroblasts enhance breast cancer cell metastasis through increased lactate.


Subject(s)
Antigens, Neoplasm , Breast Neoplasms , Cancer-Associated Fibroblasts , HMGB1 Protein , Mitogen-Activated Protein Kinases , Warburg Effect, Oncologic , Animals , Antigens, Neoplasm/metabolism , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cancer-Associated Fibroblasts/metabolism , Cancer-Associated Fibroblasts/pathology , Cell Line, Tumor , Cell Movement/physiology , Female , HMGB1 Protein/metabolism , Humans , MCF-7 Cells , Mice , Mitogen-Activated Protein Kinases/metabolism
15.
Nano Lett ; 20(7): 5400-5407, 2020 Jul 08.
Article in English | MEDLINE | ID: mdl-32496795

ABSTRACT

Nodal surface-based topological semimetals (TSMs) are drawing attention due to their unique excitation and plasmon behaviors. However, only nodal flat-surface and nodal sphere TSMs are theoretically proposed due to strict symmetry requirements. Here, we propose that a series of surface-based topological phases can be realized in a tight-binding (TB) model with sublattice symmetry. These topological phases, named as nodal flexible-surface semimetals, include not only nodal surface and nodal sphere TSMs but also novel phases, like nodal tube, nodal crossbar, and nodal hourglass-like surface TSMs. According to the TB model, a family of carbon nanotube networks are then identified as nodal flexible-surface TSMs by first-principles calculations, and the topological phase transitions between these TSMs can be induced by strains. Moreover, the nodal flexible-surface TSMs with intrinsic high density of states at the Fermi level and special drumhead surface states are promising for studying high-temperature superconductors and strong correlation effects.

16.
Phys Chem Chem Phys ; 22(16): 8713-8718, 2020 Apr 29.
Article in English | MEDLINE | ID: mdl-32270831

ABSTRACT

Critical topological phases, possessing flat bands, provide a platform to study unique topological properties and transport phenomena under a many-body effect. Here, we propose that critical nodal points and nodal lines or rings can be found in Kagome lattices. After the C3 rotation symmetry of a single-layer Kagome lattice is eliminated, a quadratic nodal point splits into two critical nodal points. When the layered Kagome lattices are stacked into a three-dimensional (3D) structure, critical nodal lines or rings can be generated by tuning the interlayer coupling. Furthermore, we use Kagome graphene as an example to identify that these critical phases could be obtained in real materials. We also discuss flat-band-induced ferromagnetism. It is found that the flat band splits into two spin-polarized bands by hole-doping, and as a result the Dirac-type critical phases evolve into Weyl-type phases.

17.
Proc Natl Acad Sci U S A ; 117(12): 6362-6369, 2020 Mar 24.
Article in English | MEDLINE | ID: mdl-32161125

ABSTRACT

Shrinking the size of a bulk metal into nanoscale leads to the discreteness of electronic energy levels, the so-called Kubo gap δ. Renormalization of the electronic properties with a tunable and size-dependent δ renders fascinating photon emission and electron tunneling. In contrast with usual three-dimensional (3D) metal clusters, here we demonstrate that Kubo gap δ can be achieved with a two-dimensional (2D) metallic transition metal dichalcogenide (i.e., 1T'-phase MoTe2) nanocluster embedded in a semiconducting polymorph (i.e., 1H-phase MoTe2). Such a 1T'/1H MoTe2 nanodomain resembles a 3D metallic droplet squeezed in a 2D space which shows a strong polarization catastrophe while simultaneously maintaining its bond integrity, which is absent in traditional δ-gapped 3D clusters. The weak screening of the host 2D MoTe2 leads to photon emission of such pseudometallic systems and a ballistic injection of carriers in the 1T'/1H/1T' homojunctions which may find applications in sensors and 2D reconfigurable devices.

18.
Nanotechnology ; 30(47): 475401, 2019 Nov 22.
Article in English | MEDLINE | ID: mdl-31430722

ABSTRACT

Carbon atomic chain, linear benzene polymers, and carbon nanothreads are all one-dimensional (1D) ultrathin carbon structures. They possess excellent electronic and mechanical properties; however, their thermal transport properties have been rarely explored. Here, we systematically study their thermal conductance by combining the nonequilibrium Green's function and force field methods. The thermal conductance varies from 0.24 to 1.00 nW K-1 at 300 K, and phonon transport in the linear benzene polymers and carbon nanothreads is strongly dependent on the connectivity styles between the benzene rings. We propose a simple 1D model, namely force-constant model, that explains the complicated transport processes in these structures. Our study not only reveals intrinsic mechanisms of phonon transport in these carbon structures, but also provides an effective method to analyze thermal properties of other 1D ultrathin structures made of only several atomic chains.

19.
Article in English | MEDLINE | ID: mdl-30930952

ABSTRACT

BACKGROUND: Shenfu injection (SFI) has shown a remarkable therapeutic effect in patients with chronic heart failure (CHF) during the acute phase of symptom aggravation since it became commercially available in 1987. However, the therapeutic effect of SFI has not been validated in a standard clinical study. As a pilot clinical trial, this study aimed to evaluate the safety and efficacy of SFI for treatment of CHF patients during the acute phase. METHODS: A total of 160 patients experiencing acute phase CHF were enrolled in this study and randomly assigned to receive the placebo (placebo group, 150 ml glucose (GS)) or SFI (SFI group, 50 ml SFI + 100 ml GS) in addition to their standard medications for CHF treatment. The treatment lasted for 7 ± 1 days, and the follow-up continued for 28 ± 3 days after treatment. The primary endpoints were New York Heart Association (NYHA) classification and Traditional Chinese Medicine (TCM) syndrome scores. RESULTS: After 7±1 days of treatment, the efficacy of SFI according to improvements in NYHA and TCM syndrome scores in the SFI group (78.38% and 89.19%, respectively) was significantly higher than that in the placebo group (61.43% and 60.00%, respectively; P<0.05). The SFI group had a longer increase in amplitude than the placebo group (113.00 m versus 82.99 m, P<0.05). The incidence of adverse events and other safety indices showed no significant differences between the two groups. CONCLUSION: SFI combined with conventional therapy for treatment of CHF during acute symptom aggravation ameliorated the cardiac dysfunction and clinical symptoms and improved the patients' quality of life without any significant AEs compared with the conventional therapy alone.

20.
Phys Chem Chem Phys ; 20(36): 23500-23506, 2018 Sep 19.
Article in English | MEDLINE | ID: mdl-30183022

ABSTRACT

Topological metals/semimetals (TMs) have emerged as a new frontier in the field of quantum materials. A few two-dimensional (2D) boron sheets have been suggested as Dirac materials, however, to date TMs made of three-dimensional (3D) boron structures have not been found. Herein, by means of systematic first principles computations, we discovered that a rather stable 3D boron allotrope, namely 3D-α' boron, is a nodal-chain semimetal. In momentum space, six nodal lines and rings contact each other and form a novel spindle nodal chain. This 3D-α' boron can be formed by stacking 2D wiggle α' boron sheets, which are also nodal-ring semimetals. In addition, our chemical bond analysis revealed that the topological properties of the 3D and 2D boron structures are related to the π bonds between boron atoms, however, the bonding characteristics are different from those in the 2D and 3D carbon structures.

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