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1.
Nature ; 628(8008): 515-521, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38509374

RESUMEN

The convergence of topology and correlations represents a highly coveted realm in the pursuit of new quantum states of matter1. Introducing electron correlations to a quantum spin Hall (QSH) insulator can lead to the emergence of a fractional topological insulator and other exotic time-reversal-symmetric topological order2-8, not possible in quantum Hall and Chern insulator systems. Here we report a new dual QSH insulator within the intrinsic monolayer crystal of TaIrTe4, arising from the interplay of its single-particle topology and density-tuned electron correlations. At charge neutrality, monolayer TaIrTe4 demonstrates the QSH insulator, manifesting enhanced nonlocal transport and quantized helical edge conductance. After introducing electrons from charge neutrality, TaIrTe4 shows metallic behaviour in only a small range of charge densities but quickly goes into a new insulating state, entirely unexpected on the basis of the single-particle band structure of TaIrTe4. This insulating state could arise from a strong electronic instability near the van Hove singularities, probably leading to a charge density wave (CDW). Remarkably, within this correlated insulating gap, we observe a resurgence of the QSH state. The observation of helical edge conduction in a CDW gap could bridge spin physics and charge orders. The discovery of a dual QSH insulator introduces a new method for creating topological flat minibands through CDW superlattices, which offer a promising platform for exploring time-reversal-symmetric fractional phases and electromagnetism2-4,9,10.

2.
J Hepatol ; 80(1): 82-98, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37838036

RESUMEN

BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) is among the most prevalent and lethal cancers worldwide. The tumor microenvironment (TME) contributes to the poor response of patients with HCC to current therapies, while tumor vascular endothelial cells (ECs) are fundamental TME components that significantly contribute to tumor progression. However, the specific functions and mechanisms of tumor vascular ECs in HCC remain unclear. METHODS: We screened and validated diacylglycerol kinase gamma (DGKG) hyper-expression specifically in HCC tumor vascular ECs. Single-cell RNA-sequencing, cytometry by time-of-flight, and in vitro and in vivo studies were performed to investigate the functions of endothelial DGKG. Multiplexed immunohistochemistry staining and flow cytometry were used to evaluate changes in the TME. RESULTS: Functionally, endothelial DGKG promotes tumor angiogenesis and immunosuppressive regulatory T-cell differentiation in HCC. Of significance, we found that HIF-1α activates DGKG transcription by directly binding to its promoter region under hypoxia. Upregulated DGKG promotes HCC progression by recruiting ubiquitin specific peptidase 16 to facilitate ZEB2 deubiquitination, which increases TGF-ß1 secretion, thus inducing tumor angiogenesis and regulatory T-cell differentiation. Importantly, targeting endothelial DGKG potentiated the efficiency of dual blockade of PD-1 and VEGFR-2. CONCLUSION: Hypoxia-induced EC-specific DGKG hyper-expression promotes tumor angiogenesis and immune evasion via the ZEB2/TGF-ß1 axis, suggesting EC-specific DGKG as a potential therapeutic target for HCC. IMPACT AND IMPLICATIONS: Here, we reported that hypoxia-induced endothelial cell-specific DGKG hyper-expression promotes angiogenesis and immune evasion in HCC by recruiting USP16 for K48-linked deubiquitination and inducing the subsequent stabilization of ZEB2, leading to increased TGF-ß1 secretion. Most importantly, endothelial DGKG inhibition greatly improved the efficacy of the dual combination of anti-VEGFR2 and anti-PD-1 treatment in a mouse HCC model, significantly inhibiting the malignant progression of HCC and improving survival. This preclinical study supports the targeting of endothelial DGKG as a potential strategy for precision HCC treatment.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Ratones , Animales , Humanos , Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/patología , Factor de Crecimiento Transformador beta1/metabolismo , Células Endoteliales/metabolismo , Evasión Inmune , Angiogénesis , Línea Celular Tumoral , Neovascularización Patológica/metabolismo , Hipoxia/metabolismo , Modelos Animales de Enfermedad , Microambiente Tumoral
3.
Magn Reson Med ; 92(3): 1064-1078, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38726772

RESUMEN

PURPOSE: This study aims to develop and evaluate a novel cardiovascular MR sequence, MyoFold, designed for the simultaneous quantifications of myocardial tissue composition and wall motion. METHODS: MyoFold is designed as a 2D single breathing-holding sequence, integrating joint T1/T2 mapping and cine imaging. The sequence uses a 2-fold accelerated balanced SSFP (bSSFP) for data readout and incorporates electrocardiogram synchronization to align with the cardiac cycle. MyoFold initially acquires six single-shot inversion-recovery images, completed during the diastole of six successive heartbeats. T2 preparation (T2-prep) is applied to introduce T2 weightings for the last three images. Subsequently, over the following six heartbeats, segmented bSSFP is performed for the movie of the entire cardiac cycle, synchronized with an electrocardiogram. A neural network trained using numerical simulations of MyoFold is used for T1 and T2 calculations. MyoFold was validated through phantom and in vivo experiments, with comparisons made against MOLLI, SASHA, T2-prep bSSFP, and the conventional cine. RESULTS: In phantom studies, MyoFold exhibited a 10% overestimation in T1 measurements, whereas T2 measurements demonstrated high accuracy. In vivo experiments revealed that MyoFold T1 had comparable accuracy to SASHA and precision similar to MOLLI. MyoFold demonstrated good agreement with T2-prep bSSFP in myocardial T2 measurements. No significant differences were observed in the quantification of left-ventricle wall thickness and function between MyoFold and the conventional cine. CONCLUSION: MyoFold presents as a rapid, simple, and multitasking approach for quantitative cardiovascular MR examinations, offering simultaneous assessment of tissue composition and wall motion. The sequence's multitasking capabilities make it a promising tool for comprehensive cardiac evaluations in clinical settings.


Asunto(s)
Algoritmos , Corazón , Imagen por Resonancia Cinemagnética , Fantasmas de Imagen , Humanos , Corazón/diagnóstico por imagen , Imagen por Resonancia Cinemagnética/métodos , Masculino , Miocardio , Procesamiento de Imagen Asistido por Computador/métodos , Electrocardiografía , Reproducibilidad de los Resultados , Femenino , Adulto , Interpretación de Imagen Asistida por Computador/métodos
4.
Nano Lett ; 23(6): 2287-2294, 2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36898060

RESUMEN

Strong coupling between light and mechanical strain forms the foundation for next-generation optical micro- and nano-electromechanical systems. Such optomechanical responses in two-dimensional materials present novel types of functionalities arising from the weak van der Waals bond between atomic layers. Here, by using structure-sensitive megaelectronvolt ultrafast electron diffraction, we report the experimental observation of optically driven ultrafast in-plane strain in the layered group IV monochalcogenide germanium sulfide (GeS). Surprisingly, the photoinduced structural deformation exhibits strain amplitudes of order 0.1% with a 10 ps fast response time and a significant in-plane anisotropy between zigzag and armchair crystallographic directions. Rather than arising due to heating, experimental and theoretical investigations suggest deformation potentials caused by electronic density redistribution and converse piezoelectric effects generated by photoinduced electric fields are the dominant contributors to the observed dynamic anisotropic strains. Our observations define new avenues for ultrafast optomechanical control and strain engineering within functional devices.

5.
Magn Reson Med ; 90(5): 1979-1989, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37415445

RESUMEN

PURPOSE: To develop and evaluate a deep neural network (DeepFittingNet) for T1 /T2 estimation of the most commonly used cardiovascular MR mapping sequences to simplify data processing and improve robustness. THEORY AND METHODS: DeepFittingNet is a 1D neural network composed of a recurrent neural network (RNN) and a fully connected (FCNN) neural network, in which RNN adapts to the different number of input signals from various sequences and FCNN subsequently predicts A, B, and Tx of a three-parameter model. DeepFittingNet was trained using Bloch-equation simulations of MOLLI and saturation-recovery single-shot acquisition (SASHA) T1 mapping sequences, and T2 -prepared balanced SSFP (T2 -prep bSSFP) T2 mapping sequence, with reference values from the curve-fitting method. Several imaging confounders were simulated to improve robustness. The trained DeepFittingNet was tested using phantom and in-vivo signals, and compared to the curve-fitting algorithm. RESULTS: In testing, DeepFittingNet performed T1 /T2 estimation of four sequences with improved robustness in inversion-recovery T1 estimation. The mean bias in phantom T1 and T2 between the curve-fitting and DeepFittingNet was smaller than 30 and 1 ms, respectively. Excellent agreements between both methods was found in the left ventricle and septum T1 /T2 with a mean bias <6 ms. There was no significant difference in the SD of both the left ventricle and septum T1 /T2 between the two methods. CONCLUSION: DeepFittingNet trained with simulations of MOLLI, SASHA, and T2 -prep bSSFP performed T1 /T2 estimation tasks for all these most used sequences. Compared with the curve-fitting algorithm, DeepFittingNet improved the robustness for inversion-recovery T1 estimation and had comparable performance in terms of accuracy and precision.


Asunto(s)
Corazón , Imagen por Resonancia Magnética , Imagen por Resonancia Magnética/métodos , Corazón/diagnóstico por imagen , Redes Neurales de la Computación , Algoritmos , Ventrículos Cardíacos , Fantasmas de Imagen , Reproducibilidad de los Resultados
6.
Nanotechnology ; 34(25)2023 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-36958026

RESUMEN

Addressing respiratory infectious diseases remains one of the main priorities due to the increased risk of exposure caused by population growth, increasing international travel and commerce, and most recently, the COVID-19 outbreak. In the war against respiratory diseases, facemasks are powerful tools to obstruct the penetration of microorganisms, thereby protecting the wearer from infections. Nonetheless, the intercepted microorganisms on the surface of facemasks may proliferate and lead to secondary infection. To solve this problem, atomic layer deposition is introduced to deposit uniform and mechanically robust ZnO layers on polypropylene (PP) nonwoven fabrics, a widely used raw material in fabricating facemasks. The loading of ZnO demonstrates no adverse effects on the separation performance of facemasks, and the filtration efficiency of the facemasks towards different types of nanoparticles remains higher than 98.9%. Moreover, the modified PP nonwoven fabrics are granted with excellent antibacterial activity and photocatalytic sterilization ability, which can inactivate both germ-negative and germ-positive bacteria (E. coliandS. aureus) effectively with and without light illumination. Therefore, the modified PP nonwoven fabrics are potential candidates to be used as the outer layer on facemasks and endow them with photocatalytic antibacterial activity.


Asunto(s)
COVID-19 , Óxido de Zinc , Humanos , Polipropilenos , Máscaras , Antibacterianos
7.
Nano Lett ; 22(10): 4145-4152, 2022 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-35532538

RESUMEN

Two-dimensional (2D) transition metal dichalcogenides are promising materials platforms for a variety of optoelectronic device applications. Janus 2D materials are a rising class of 2D materials with low symmetry, which leads to the emergence of out-of-plane electric polarization and piezoelectricity. Using first-principles density functional theory, we show that monolayer and bilayer heterostructure Janus MoSSe moieties exhibit strong nonlinear optical responses that are vanishing in the non-Janus form. The absence of horizontal mirror plane symmetry enables a circular photocurrent as well as a large out-of-plane second harmonic generation (SHG) and shift photocurrent. Through a comparative study of the Janus heterostructure MoS2-MoSSe on five distinct stacking configurations, we find that the magnitude of the out-of-plane SHG in the Janus heterostructure is enhanced due to the interlayer coupling and interference effect compared to that of monolayer MoSSe. Thus, Janus 2D materials offer a unique opportunity for exploring nonlinear optical phenomena and designing configurable layered nonlinear optical materials.

8.
Chemistry ; 28(38): e202200696, 2022 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-35491720

RESUMEN

Nanosheets of nickel doped SAPO-34 molecular sieves in thickness of ∼10 nm (denoted as NS-Ni-SAPO-34) has been successfully prepared through a morphology-reserved method of synthesis. A special aluminum phosphate in two-dimensional layered structure is used as precursor and converts to crystallized SAPO-34 molecular sieve, in nanosheet morphology reserved from the aluminum phosphate precursor, under hydrothermal conditions with tetraethyl orthosilicate and templates of mixed amines added. It is found that adequate amount of nickel, ∼5 wt %, added to the synthetic system is a key factor for the morphology-reserved synthesis. By characterization, the nickel is proved to be doped in the framework of the molecular sieve, which more likely helps to balance the high surface energy of nanosheet products. The NS-Ni-SAPO-34 shows excellent catalytic performance for oxidation of cyclohexanone to adipic acid by gaseous oxygen.

9.
Nano Lett ; 21(6): 2505-2511, 2021 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-33689385

RESUMEN

Crystalline two-dimensional (2D) superconductors (SCs) with low carrier density are an exciting new class of materials in which electrostatic gating can tune superconductivity, electronic interactions play a prominent role, and electrical transport properties may directly reflect the topology of the Fermi surface. Here, we report the dramatic enhancement of superconductivity with decreasing thickness in semimetallic Td-MoTe2, with critical temperature (Tc) increasing up to 7.6 K for monolayers, a 60-fold increase with respect to the bulk Tc. We show that monolayers possess a similar electronic structure and density of states (DOS) as the bulk, implying that electronic interactions play a strong role in the enhanced superconductivity. Reflecting the low carrier density, the critical temperature, magnetic field, and current density are all tunable by an applied gate voltage. The response to high in-plane magnetic fields is distinct from that of other 2D SCs and reflects the canted spin texture of the electron pockets.

10.
Nano Lett ; 21(5): 2191-2198, 2021 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-33646790

RESUMEN

Materials with interfaces often exhibit extraordinary phenomena exemplified by rich physics, such as high-temperature superconductivity and enhanced electronic correlations. However, demonstrations of confined interfaces to date have involved intensive effort and fortuity, and no simple path is consistently available. Here, we report the achievement of interfacial superconductivity in the nonsuperconducting parent compounds AEFe2As2, where AE = Ca, Sr, or Ba, by simple subsequent annealing of the as-grown samples in an atmosphere of As, P, or Sb. Our results indicate that the superconductivity originates from electron transfer at the interface of the hybrid van der Waals heterostructures, consistent with the two-dimensional superconducting transition observed. The observations suggest a common origin of interfaces for the nonbulk superconductivity previously reported in the AEFe2As2 compound family and provide insight for the further exploration of interfacial superconductivity.

11.
Opt Lett ; 46(5): 1073-1076, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33649660

RESUMEN

We investigate dynamical generation of macroscopic nonlocal entanglements between two remote massive magnon-superconducting-circuit hybrid systems. Two fiber-coupled microwave cavities are employed to serve as an interaction channel connecting two sets of macroscopic hybrid units, each containing a magnon (hosted by an yttrium-iron-garnet sphere) and a superconducting-circuit qubit. Surprisingly, it is found that stronger coupling does not necessarily mean faster entanglement generation. The proposed hybrid system allows the existence of an optimal fiber coupling strength that requires the shortest amount of time to generate a systematic maximal entanglement. Our theoretical results are shown to be within the scope of specific parameters that can be achieved with current technology. The noise effects on the implementation of systems are also treated in a general environment, suggesting the robustness of entanglement generation. Our discrete-variable qubit-like entanglement theory of magnons may lead to direct applications in various quantum information tasks.

12.
Surg Today ; 51(5): 695-702, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33128594

RESUMEN

PURPOSE: To explore the role of indocyanine green (ICG) fluorescence navigation in laparoscopic hepatectomy and investigate if the timing of its administration influences the intraoperative observation. METHODS: The subjects of this retrospective study were 120 patients who underwent laparoscopic hepatectomy; divided into an ICG-FN group (n = 57) and a non-ICG-FN group (n = 63). We analyzed the baseline data and operative data. RESULTS: There were no remarkable differences in baseline data such as demographic characteristics, lesion-related characteristics, and liver function parameters between the groups. Operative time and intraoperative blood loss were significantly lower in the ICG-FN group. The rate of R0 resection of malignant tumors was comparable in the ICG-FN and non-ICG-FN groups, but the wide surgical margin rate was significantly higher in the ICG-FN group. The administration of ICG 0-3 or 4-7 days preoperatively did not affect the intraoperative fluorescence imaging. Operative time, intraoperative blood loss, and a wide surgical margin correlated with ICG fluorescence navigation. ICG fluorescence navigation helped to minimize intraoperative blood loss and achieve a wide surgical margin. CONCLUSION: ICG fluorescence navigation is safe and efficient in laparoscopic hepatectomy. It helps to achieve a wide surgical margin, which could result in a better prognosis. The administration of ICG 0-3 days preoperatively is acceptable.


Asunto(s)
Hepatectomía/métodos , Verde de Indocianina/administración & dosificación , Laparoscopía/métodos , Hepatopatías/cirugía , Hígado/cirugía , Imagen Óptica/métodos , Cirugía Asistida por Computador/métodos , Adulto , Anciano , Pérdida de Sangre Quirúrgica/prevención & control , Pérdida de Sangre Quirúrgica/estadística & datos numéricos , Femenino , Humanos , Masculino , Márgenes de Escisión , Persona de Mediana Edad , Tempo Operativo , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento
13.
J Cell Mol Med ; 24(17): 10216-10222, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32692470

RESUMEN

A microarray-based high-throughput screening of human circulating circular RNA (circRNA) was applied with five patients newly diagnosed with hepatocellular carcinoma (HCC), five patients with HBV-positive chronic hepatitis (CH) and five healthy controls (NC) enrolled. The plasma of HCC patients after hepatectomy was also collected. After multiple staged validation, we obtained five circRNAs as candidate. Based on the stratified risk score analysis, three increased circRNAs including circ_0009582, circ_0037120 and circ_0140117 were confirmed as candidate circulating fingerprints for distinguishing HCC from CH or NC group. With the combination of AFP, higher sensitivity and specificity were further guaranteed, suggesting that circ_0009582, circ_0037120 and circ_0140117 may serve as potential biomarkers for predicting the occurrence of HCC in patients with HBV infection.


Asunto(s)
Carcinoma Hepatocelular/genética , Ácidos Nucleicos Libres de Células/genética , Hepatitis B/genética , Neoplasias Hepáticas/genética , ARN Circular/genética , Biomarcadores de Tumor/genética , Carcinoma Hepatocelular/virología , Femenino , Perfilación de la Expresión Génica/métodos , Regulación Neoplásica de la Expresión Génica/genética , Hepatectomía/métodos , Hepatitis B/virología , Virus de la Hepatitis B/patogenicidad , Humanos , Neoplasias Hepáticas/virología , Masculino , Persona de Mediana Edad
14.
J Am Chem Soc ; 142(41): 17499-17507, 2020 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-32942848

RESUMEN

Interlayer coupling plays essential roles in the quantum transport, polaritonic, and electrochemical properties of stacked van der Waals (vdW) materials. In this work, we report the unconventional interlayer coupling in vdW heterostructures (HSs) by utilizing an emerging 2D material, Janus transition metal dichalcogenides (TMDs). In contrast to conventional TMDs, monolayer Janus TMDs have two different chalcogen layers sandwiching the transition metal and thus exhibit broken mirror symmetry and an intrinsic vertical dipole moment. Such a broken symmetry is found to strongly enhance the vdW interlayer coupling by as much as 13.2% when forming MoSSe/MoS2 HS as compared to the pristine MoS2 counterparts. Our noncontact ultralow-frequency Raman probe, linear chain model, and density functional theory calculations confirm the enhancement and reveal the origins as charge redistribution in Janus MoSSe and reduced interlayer distance. Our results uncover the potential of tuning interlayer coupling strength through Janus heterostacking.

15.
J Am Chem Soc ; 142(36): 15513-15526, 2020 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-32786743

RESUMEN

Transformations between different atomic configurations of a material oftentimes bring about dramatic changes in functional properties as a result of the simultaneous alteration of both atomistic and electronic structure. Transformation barriers between polytypes can be tuned through compositional modification, generally in an immutable manner. Continuous, stimulus-driven modulation of phase stabilities remains a significant challenge. Utilizing the metal-insulator transition of VO2, we exemplify that mobile dopants weakly coupled to the crystal lattice provide a means of imbuing a reversible and dynamical modulation of the phase transformation. Remarkably, we observe a time- and temperature-dependent evolution of the relative phase stabilities of the M1 and R phases of VO2 in an "hourglass" fashion through the relaxation of interstitial boron species, corresponding to a 50 °C modulation of the transition temperature achieved within the same compound. The material functions as both a chronometer and a thermometer and is "reset" by the phase transition. Materials possessing memory of thermal history hold promise for applications such as neuromorphic computing, atomic clocks, thermometry, and sensing.

16.
Small ; 16(5): e1906347, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31943782

RESUMEN

Atomically thin transition metal dichalcogenides (TMDs) in their excited states can serve as exceptionally small building blocks for active optical platforms. In this scheme, optical excitation provides a practical approach to control light-TMD interactions via the photocarrier generation, in an ultrafast manner. Here, it is demonstrated that via a controlled generation of photocarriers the second-harmonic generation (SHG) from a monolayer MoS2 crystal can be substantially modulated up to ≈55% within a timeframe of ≈250 fs, a set of performance characteristics that showcases the promise of low-dimensional materials for all-optical nonlinear data processing. The combined experimental and theoretical study suggests that the large SHG modulation stems from the correlation between the second-order dielectric susceptibility χ(2) and the density of photoexcited carriers in MoS2 . Indeed, the depopulation of the conduction band electrons, at the vicinity of the high-symmetry K/K' points of MoS2 , suppresses the contribution of interband electronic transitions in the effective χ(2) of the monolayer crystal, enabling the all-optical modulation of the SHG signal. The strong dependence of the second-order optical response on the density of photocarriers reveals the promise of time-resolved nonlinear characterization as an alternative route to monitoring carrier dynamics in excited states of TMDs.

17.
Nano Lett ; 19(2): 1371-1378, 2019 02 13.
Artículo en Inglés | MEDLINE | ID: mdl-30620607

RESUMEN

Oxygen reduction reaction (ORR) is of paramount importance in polymer electrolyte membrane fuel cells due to its sluggish kinetics. In this work, a plasmon-induced hot electrons enhancement method is introduced to enhance ORR property of the silver (Ag)-based electrocatalysts. Three types of Ag nanostructures with differently localized surface plasmon resonances have been used as electrocatalysts. The thermal effect of plasmonic-enhanced ORR can be minimized in our work by using graphene as the support of Ag nanoparticles. By tuning the resonance positions and laser power, the enhancement of ORR properties of Ag catalysts has been optimized. Among these catalysts, Ag nanotriangles after excitation show the highest mass activity and reach 0.086 mA/µgAg at 0.8 V, which is almost 17 times that of a commercial Pt/C catalyst after the price is accounted. Our results demonstrate that the hot electrons generated from surface plasmon resonance can be utilized for electrochemical reaction, and tuning the resonance positions by light is a promising and viable approach to boost electrochemical reactions.

18.
Nano Lett ; 17(8): 5027-5034, 2017 08 09.
Artículo en Inglés | MEDLINE | ID: mdl-28671472

RESUMEN

Nonlinear optical properties of materials such as second and higher order harmonic generation and electro-optic effect play pivotal roles in lasers, frequency conversion, electro-optic modulators, switches, and so forth. The strength of nonlinear optical responses highly depends on intrinsic crystal symmetry, transition dipole moments, specific optical excitation, and local environment. Using first-principles electronic structure theory, here we predict giant second harmonic generation (SHG) in recently discovered two-dimensional (2D) ferroelectric-ferroelastic multiferroics-group IV monochalcogenides (i.e., GeSe, GeS, SnSe, and SnS). Remarkably, the strength of SHG susceptibility in GeSe and SnSe monolayers is more than 1 order of magnitude higher than that in monolayer MoS2, and 2 orders of magnitude higher than that in monolayer hexagonal BN. Their extraordinary SHG is dominated by the large residual of two opposite intraband contributions in the SHG susceptibility. More importantly, the SHG polarization anisotropy is strongly correlated with the intrinsic ferroelastic and ferroelectric orders in group IV monochalcogenide monolayers. Our present findings provide a microscopic understanding of the large SHG susceptibility in 2D group IV monochalcogenide multiferroics from first-principles theory and open up a variety of new avenues for 2D ferroelectrics, multiferroics, and nonlinear optoelectronics, for example, realizing active electrical/optical/mechanical switching of ferroic orders in 2D multiferroics and in situ ultrafast optical characterization of local atomistic and electronic structures using noncontact noninvasive optical SHG techniques.

19.
Nano Lett ; 17(1): 467-475, 2017 01 11.
Artículo en Inglés | MEDLINE | ID: mdl-27935725

RESUMEN

Novel materials with nontrivial electronic and photonic band topology are crucial for realizing novel devices with low power consumption and heat dissipation and quantum computing free of decoherence. Here, we theoretically predict a novel class of ternary transition metal chalcogenides that exhibit dual topological characteristics, quantum spin Hall insulators (QSHIs) in their two-dimensional (2D) monolayers and topological Weyl semimetals in their 3D noncentrosymmetric crystals upon van der Waals (vdW) stacking. Remarkably, we find that one can create and annihilate Weyl fermions and realize the transition between Type-I and Type-II Weyl fermions by tuning vdW interlayer spacing, providing the missing physical picture of the evolution from 2D QSHIs to 3D Weyl semimetals. Our results also show that these materials possess excellent thermodynamic stability and weak interlayer binding; some of them were synthesized two decades ago, implying their great potentials for experimental synthesis, characterization, and vdW heterostacking. Moreover, their ternary nature will offer more tunability for electronic structure by controlling different stoichiometry and valence charges. Our findings provide an ideal materials platform for realizing QSH effect and exploring fundamental topological phase transition and will open up a variety of new opportunities for two-dimensional materials and topological materials research.

20.
Hepatobiliary Pancreat Dis Int ; 16(4): 364-369, 2017 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-28823365

RESUMEN

BACKGROUND: Fast-track surgery and enhanced recovery after surgery have been applied to many surgical procedures; however, data on fast-track surgery and enhanced recovery after surgery following liver transplantation is limited. This study aimed to conduct a prospective study to determine the effects of fast-track surgery on prognosis after liver transplantation. METHODS: This was a prospective, single-blinded, randomized study. One hundred twenty-eight patients undergoing liver transplantation were selected for the fast-track (FT group, n=54) or conventional process (NFT group, n=74). The primary endpoints were intensive care unit (ICU) stay and hospital stay. The secondary endpoints were as follows: operative time, anhepatic phase time, intraoperative blood loss, intraoperative blood transfusion volume, postoperative complications, readmission rate, and postoperative mortality. RESULTS: There was no significant difference in preoperative demographics between the two groups. The median ICU stay was 2 days (range 1-7 days) in the FT group and 5 days (range 3-12 days) in the NFT group (P<0.01). Furthermore, the hospital stay was also significantly reduced in the FT group (P<0.01). The operative time, anhepatic phase time, intraoperative blood loss, and intraoperative blood transfusion volume were decreased in the FT group compared with the NFT group (P<0.05). Based on Spearman correlation analysis, the ICU stay and hospital stay may be positively correlated with operative time, anhepatic phase time and intraoperative blood loss. There were no differences in the incidence of postoperative complications, readmissions, and postoperative mortality between the two groups. CONCLUSION: Fast-track procedures effectively reduce the ICU stay and hospital stay without adversely affecting prognosis. This study demonstrated that fast-track protocols are safe and feasible in liver transplantation.


Asunto(s)
Enfermedad Hepática en Estado Terminal/cirugía , Tiempo de Internación , Trasplante de Hígado/métodos , Adulto , Anciano , Pérdida de Sangre Quirúrgica , China , Enfermedad Hepática en Estado Terminal/diagnóstico , Enfermedad Hepática en Estado Terminal/etiología , Enfermedad Hepática en Estado Terminal/mortalidad , Femenino , Humanos , Unidades de Cuidados Intensivos , Trasplante de Hígado/efectos adversos , Trasplante de Hígado/mortalidad , Masculino , Persona de Mediana Edad , Tempo Operativo , Readmisión del Paciente , Complicaciones Posoperatorias/etiología , Estudios Prospectivos , Recuperación de la Función , Método Simple Ciego , Factores de Tiempo , Resultado del Tratamiento
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