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1.
Nanotechnology ; 35(38)2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38925105

RESUMO

Lu doped Hf0.5Zr0.5O2(HZO) ferroelectric films were prepared on Pt/TiN/SiO2/Si substrate by chemical solution deposition method, and an interfacial engineering strategy for improving the ferroelectric property was explored by capping the Lu doped HZO films with a cerium oxide layer. Compared with the Lu doped HZO film without the CeOxcoating layer, the Lu doped HZO film with the CeOxcoating layer has a larger remanent polarization (2Pr= 34.72µC cm-2) and presents weaker wake-up behavior, which result from the higher orthogonal phase ratio and the lower oxygen vacancy of the CeOxcoated Lu doped HZO film. In addition, the CeOxcoating can remarkably improve the fatigue resistance and retention performance of the Lu doped HZO films. It is hoped that the results can provide an effective approach for the realization of high-performance and highly reliable hafnium oxide based ferroelectric thin films.

2.
Phys Chem Chem Phys ; 21(28): 15327-15338, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31259339

RESUMO

Two-dimensional (2D) superconductors, which can be widely applied in optoelectronic and microelectronic devices, have gained renewed attention in recent years. Based on the crystal structure prediction method and first-principles calculations, we obtain four novel 2D tungsten boride structures of tetr-, hex-, and tri-W2B2 and hex-WB4 and investigate their bonding types, electronic properties, phonon dispersions and electron-phonon coupling (EPC). The results show that both tetr- and hex-W2B2 are intrinsic phonon-mediated superconductors with a superconducting transition temperature (Tc) of 7.8 and 1.5 K, respectively, while tri-W2B2 and hex-WB4 are normal metals. We demonstrate that carrier doping as well as biaxial strain can soften the low-frequency phonon modes and enhance the strength of the EPC. While the Tc of tetr-W2B2 can be increased to 15.4 K under a compressive strain of -2%, the Tc of hex-W2B2 can be enhanced to 5.9 K by a tensile strain of +4%. With the inclusion of spin-orbit couping (SOC), the value of Tc decreases by 38.5% in our systems. Furthermore, we explore the stabilities and mechanical properties of tetr- and hex-W2B2 and indicate that they may be prepared by growing on ZnS(100) and ZnS(111), respectively. Our findings provide novel 2D superconducting materials and will stimulate more efforts in this filed.

3.
Nanotechnology ; 29(13): 134002, 2018 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-29339566

RESUMO

Graphene has received numerous attention for future nanoelectronics and optoelectronics. The Dirac point is a key parameter of graphene that provides information about its carrier properties. There are lots of methods to tune the Dirac point of graphene, such as chemical doping, impurities, defects, and disorder. In this study, we report a different approach to tune the Dirac point of graphene using a ferroelectric polarization field. The Dirac point can be adjusted to near the ferroelectric coercive voltage regardless its original position. We have ensured this phenomenon by temperature-dependent experiments, and analyzed its mechanism with the theory of impurity correlation in graphene. Additionally, with the modulation of ferroelectric polymer, the current on/off ratio and mobility of graphene transistor both have been improved. This work provides an effective method to tune the Dirac point of graphene, which can be readily used to configure functional devices such as p-n junctions and inverters.

4.
Lab Invest ; 96(10): 1087-104, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27501050

RESUMO

Intestinal ischemic post-conditioning (IPo) protects against lung injury induced by intestinal ischemia-reperfusion (IIR) partly through promotion of expression and function of heme oxygenase-1 (HO-1). NF-E2-related factor-2 (Nrf2) is a key transcription factor that interacts with HO-1 and regulates antioxidant defense. However, the role of Nrf2 in IPo protection of IIR-induced pulmonary injury is not completely understood. Here we show that IPo significantly attenuated IIR-induced lung injury and suppressed oxidative stress and systemic inflammatory responses. IPo also increased the expression of both Nrf2 and HO-1. Consistently, the beneficial effects of IPo were abolished by ATRA and Brusatol, potent inhibitors of Nrf2. Moreover, the Nrf2 agonist t-BHQ showed similar activity as IPo. Taken together, our data suggest that Nrf2 activity, along with HO-1, plays an important role in the protective effects of IPo against IIR-induced acute lung injury.


Assuntos
Lesão Pulmonar Aguda/prevenção & controle , Intestinos/irrigação sanguínea , Pós-Condicionamento Isquêmico , Fator 2 Relacionado a NF-E2/metabolismo , Traumatismo por Reperfusão/complicações , Lesão Pulmonar Aguda/etiologia , Lesão Pulmonar Aguda/metabolismo , Animais , Glutationa Peroxidase/metabolismo , Heme Oxigenase-1/metabolismo , Interleucina-6/sangue , Pulmão/enzimologia , Masculino , Malondialdeído/metabolismo , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Distribuição Aleatória , Superóxido Dismutase/metabolismo , Fator de Necrose Tumoral alfa/sangue
5.
Microvasc Res ; 100: 9-16, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25660475

RESUMO

The excessive proliferation of vascular smooth muscle cells was key factor in the restenosis of vein graft. And the Notch signaling was demonstrated to regulate vSMC proliferation and differentiation. Soluble Jagged-1 (sJag1) can inhibit Notch signaling in vitro and in vivo; however, its capacity to suppress restenosis of vein graft remains unknown. Under the microscope, the left jugular vein of these rats was interposed into the left common carotid artery, followed without any treatment (control), or with Ad-Jag1 (treatment) or placebo (DMSO) post operation. We showed that Ad-Jag1 can attenuate restenosis of vein graft by inducing decreased proliferation and increased apoptosis in vivo. Notch1-Hey2 signaling is critical for the development of intima thickening by controlling vSMC-fate determination. By blocking Notch signaling, Ad-Jag1 can significantly inhibit intima thickening. These studies identify that Ad-Jag1 can restore the vSMC phenotype and inhibit the vSMC proliferation by suppression of Notch1 signaling, and thus open a new avenue for the treatment of restenosis in vein graft.


Assuntos
Proteínas de Ligação ao Cálcio/biossíntese , Terapia Genética/métodos , Oclusão de Enxerto Vascular/prevenção & controle , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Veias Jugulares/transplante , Proteínas de Membrana/biossíntese , Músculo Liso Vascular/transplante , Receptor Notch1/metabolismo , Transdução de Sinais , Animais , Apoptose , Proteínas de Ligação ao Cálcio/genética , Artéria Carótida Primitiva/cirurgia , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Oclusão de Enxerto Vascular/genética , Oclusão de Enxerto Vascular/metabolismo , Oclusão de Enxerto Vascular/patologia , Peptídeos e Proteínas de Sinalização Intercelular/genética , Proteína Jagged-1 , Veias Jugulares/metabolismo , Veias Jugulares/patologia , Masculino , Proteínas de Membrana/genética , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Neointima , Fenótipo , Ratos Wistar , Proteínas Serrate-Jagged , Fatores de Tempo , Transfecção , Enxerto Vascular
6.
Arterioscler Thromb Vasc Biol ; 33(12): 2733-9, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24072692

RESUMO

OBJECTIVE: Notch signaling has been implicated in the development of pulmonary arterial hypertension (PH) as reflected by increased expression of Notch member proteins that induce the proliferation of pulmonary arterial smooth muscle cells (PASMCs). Soluble Jagged1 (sJag1) has been shown to inhibit Notch signaling in vitro and in vivo; however, its capacity to suppress PH remains unknown. APPROACH AND RESULTS: Notch1, Notch3, Jagged1, and Herp2 protein were highly expressed in both the mouse model of hypoxia-induced PH and the rat model of monocrotaline-induced PH. By attenuation and reversal of multiple pathological processes that were associated with PH, adenoviral sJag1 transfection significantly reduced the proliferation and enhanced the apoptosis of PASMCs in PH, whereas vehicle had no effect. The sJag1 inhibitory effect on Notch activation is likely related to its interference with ligand-induced signaling. Importantly, the administration with adenoviral sJag1 improved the survival rate of PH rats. Furthermore, sJag1 can restore the PH-PASMCs phenotype from the dedifferentiated to the differentiated state, by giving a positive effect on the physical binding of myocardin to the CC(A/T)nGG (CArG)-containing regions of vascular smooth muscle cells-specific promoters. CONCLUSIONS: Our results demonstrated that the potential therapeutic use of the sJag1 may not only inhibit the proliferation of PASMCs but also restore the PH-PASMCs phenotype from the dedifferentiated to the differentiated state through interference with Notch-Herp2 signaling.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Terapia Genética , Hipertensão Pulmonar/prevenção & controle , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas de Membrana/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Receptores Notch/metabolismo , Transdução de Sinais , Adenoviridae/genética , Animais , Sítios de Ligação , Proteínas de Ligação ao Cálcio/genética , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Terapia Genética/métodos , Vetores Genéticos , Hipertensão Pulmonar/etiologia , Hipertensão Pulmonar/genética , Hipertensão Pulmonar/metabolismo , Hipertensão Pulmonar/patologia , Hipóxia/complicações , Peptídeos e Proteínas de Sinalização Intercelular/genética , Proteína Jagged-1 , Masculino , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Monocrotalina , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/patologia , Proteínas Nucleares/metabolismo , Fenótipo , Regiões Promotoras Genéticas , Artéria Pulmonar/metabolismo , Artéria Pulmonar/patologia , Ratos , Ratos Sprague-Dawley , Receptor Notch1/metabolismo , Receptor Notch3 , Proteínas Serrate-Jagged , Fatores de Tempo , Transativadores/metabolismo , Transdução Genética , Transfecção
7.
Am J Respir Crit Care Med ; 188(4): 482-91, 2013 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-23822766

RESUMO

RATIONALE: A proliferative and apoptosis-resistant phenotype in pulmonary arterial smooth muscle cells (PASMCs) is key to pathologic vascular remodeling in pulmonary hypertension (PH). Expression of indoleamine-2,3-dioxygenase (IDO) by vascular endothelium is a newly identified vasomotor-regulatory mechanism also involved in molecular signaling cascades governing vascular smooth muscle cell (vSMC) plasticity. OBJECTIVES: To investigate the therapeutic potential of enhanced endothelial IDO in development of PH and its associated vascular remodeling. METHODS: We used loss and gain of function in vivo studies to establish the role and determine the therapeutic effect of endothelial IDO in hypoxia-induced PH in mice and monocrotaline-induced PH in rats. We also studied PASMC phenotype in an IDO-high in vivo and in vitro tissue microenvironment. MEASUREMENTS AND MAIN RESULTS: The endothelium was the primary site for endogenous IDO production within mouse lung, and the mice lacking this gene had exaggerated hypoxia-induced PH. Conversely, augmented pulmonary endothelial IDO expression, through a human IDO-encoding Sleeping Beauty (SB)-based nonviral gene-integrating approach, halted and attenuated the development of PH, right ventricular hypertrophy, and vascular remodeling in both preclinical models of PH. IDO derived from endothelial cells promoted apoptosis in PH-PASMCs through depolarization of mitochondrial transmembrane potential and down-regulated PH-PASMC proliferative/synthetic capacity through enhanced binding of myocardin to CArG box DNA sequences present within the promoters of vSMC differentiation-specific genes. CONCLUSIONS: Enhanced endothelial IDO ameliorates PH and its associated vascular structural remodeling through paracrine phenotypic modulation of PH-PASMCs toward a proapoptotic and less proliferative/synthetic state.


Assuntos
Endotélio Vascular/metabolismo , Hipertensão Pulmonar/enzimologia , Hipertensão Pulmonar/prevenção & controle , Indolamina-Pirrol 2,3,-Dioxigenase/biossíntese , Pulmão/enzimologia , Animais , Apoptose , Proliferação de Células , Células Cultivadas , Elementos de DNA Transponíveis , Camundongos , Miócitos de Músculo Liso/metabolismo , Ratos , Regulação para Cima , Proteínas Elk-1 do Domínio ets/fisiologia
8.
Front Oncol ; 14: 1402297, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38800406

RESUMO

The co-occurrence of distinct lung cancer types within the same lobe is an exceedingly rare phenomenon. Here, we present a unique case wherein primary invasive squamous cell carcinoma and invasive adenocarcinoma concurrently manifested in the identical lung lobe. Additionally, we provide a comprehensive overview of the diagnosis and treatment approaches for multiple primary lung cancers, along with highlighting existing challenges based on the most recent guidelines. Our case underscores the importance of sampling each lesion individually, conducting separate diagnostic procedures, and determining the histological subtype for effective treatment planning irrespective of their location or size.

9.
Micromachines (Basel) ; 14(11)2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-38004908

RESUMO

High-purity germanium detectors, widely employed in fields such as aerospace applications based on radiation detection principles, have garnered attention due to their broad detection range and fast response time. However, these detectors often require larger sensitive area volumes to achieve larger signals and higher detection efficiency. Additionally, the large distance between the electrodes contributes to an issue of incomplete charge collection, which significantly restricts their application in space applications. To enhance the electrical performance of high-purity germanium detectors, this study introduces a strategy: designing the detector's cathode electrode into a 3D trench shape with nested complementary cathodes. This design greatly reduces the electrode spacing, endowing the detector with superior electrical characteristics, such as a smaller dead zone and improved charge collection efficiency. Performance simulations of the novel detector structure were conducted using the semiconductor device simulation software Sentaurus TCAD (2019.03). The simulation results confirmed that the nested complementary 3D trench electrode high-purity germanium detector exhibits excellent electrical features, including a larger sensitive area volume, rapid charge collection, and good cell isolations. This approach has the potential to effectively expand the application scenarios of high-purity germanium detectors. Depending on different operational environments and requirements, nested complementary 3D trench electrode high-purity germanium detectors of appropriate structural dimensions can be chosen. The experimental findings of this study hold a significant reference value for enhancing the overall structure of high purity germanium detectors and facilitating their practical application in the future.

10.
Oxid Med Cell Longev ; 2022: 3589277, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35340214

RESUMO

The disorder of mitochondrial dynamic equilibrium of lung epithelial cell is one of the critical causes of acute lung injury (ALI). Kinsenoside (Kin) serves as an active small-molecule component derived from traditional medicinal herb displaying multiple pharmacological actions in cancers, hyperglycemia, and liver disease. The objective of this study was to investigate the effects of Kin on lipopolysaccharide- (LPS-) induced ALI and further explore possible molecular mechanisms. Kin was administered orally (100 mg/kg/day) for 7 consecutive days before LPS instillation (5 mg/kg). After 12 hours, pathological injury, inflammatory response, and oxidative stress were detected. The results demonstrated that Kin significantly alleviated lung pathological injury and decreased the infiltration of inflammatory cells and the release of inflammatory mediators in bronchoalveolar lavage fluid (BALF), apart from inhibiting the production of reactive oxygen species (ROS) and lipid peroxidation. Meanwhile, Kin also promoted mitochondrial fusion and restrained mitochondrial fission in mice with ALI. In terms of mechanism, Kin pretreatment increased the phosphorylation of AMP-activated protein kinase (AMPK) and the protein level of nuclear factor erythroid 2-related factor 2 (NRF2). In Ampk-α knockout mice challenged with LPS, Kin lost its pulmonary protective effects, accompanied by lower NRF2 level. In vitro experiments further unveiled that either AMPK inhibition by Compound C or NRF2 knockdown by siRNA abolished the protective roles of Kin in LPS-treated A549 lung epithelial cells. And NRF2 activator TAT-14 could reverse the effects of Ampk-α deficiency. In conclusion, Kin possesses the ability to prevent LPS-induced ALI by modulating mitochondrial dynamic equilibrium in lung epithelial cell in an AMPK/NRF2-dependent manner.


Assuntos
Lesão Pulmonar Aguda , Lipopolissacarídeos , 4-Butirolactona/análogos & derivados , Proteínas Quinases Ativadas por AMP/metabolismo , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/metabolismo , Animais , Células Epiteliais/metabolismo , Lipopolissacarídeos/farmacologia , Pulmão/patologia , Camundongos , Monossacarídeos , Fator 2 Relacionado a NF-E2/metabolismo
11.
Light Sci Appl ; 11(1): 220, 2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35831285

RESUMO

In situ and continuous monitoring of thermal effects is essential for understanding photo-induced catalytic processes at catalyst's surfaces. However, existing techniques are largely unable to capture the rapidly changing temperatures occurring in sub-µm layers at liquid-solid interfaces exposed to light. To address this, a sensing system based on a gold-coated conventional single-mode optical fiber with a tilted fiber Bragg grating inscribed in the fiber core is proposed and demonstrated. The spectral transmission from these devices is made up of a dense comb of narrowband resonances that can differentiate between localized temperatures rapid changes at the catalyst's surface and those of the environment. By using the gold coating of the fiber as an electrode in an electrochemical reactor and exposing it to light, thermal effects in photo-induced catalysis at the interface can be decoded with a temperature resolution of 0.1 °C and a temporal resolution of 0.1 sec, without perturbing the catalytic operation that is measured simultaneously. As a demonstration, stable and reproducible correlations between the light-to-heat conversion and catalytic activities over time were measured for two different catalysis processes (linear and nonlinear). These kinds of sensing applications are ideally suited to the fundamental qualities of optical fiber sensors, such as their compact size, flexible shape, and remote measurement capability, thereby opening the way for various thermal monitoring in hard-to-reach spaces and rapid catalytic reaction processes.

12.
Anal Chim Acta ; 1146: 174-183, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33461714

RESUMO

Due to their highly porous structures, metal organic framework materials are widely used in analytic areas. In this paper, Cr-metal organic framework (MIL-101(Cr)) modified electrode was prepared and then was used as electrochemical sensor for the detection of bisphenol A (BPA). By using one kind of surfactant of cetyltrimethylammonium bromide (CTAB), the analytic performances of MIL-101 (Cr) towards BPA detection were greatly improved. Compared with pure MIL-101 (Cr), the differential pulse voltammetry (DPV) behavior of CTAB/MIL-101 (Cr) was improved 3.0 times in the presence of BPA. The hydrophobic long chain alkanes of CTAB can improve the enrichment and electrochemical oxidation for BPA. The CTAB/MIL-101 (Cr) sensor exhibited a linear range from 20 to 350 nM and a low detection limit of 9.95 nM (LOD = 3sb/S) and showed good reproducibility, stability and selectivity. Finally, real samples of dusts from E-waste recycling area in South China were collected and the CTAB/MIL-101 (Cr) sensor demonstrated satisfactory results for BPA detection from these dust samples.

13.
Microsyst Nanoeng ; 7: 55, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34567768

RESUMO

Assessment of lung and heart states is of critical importance for patients with pneumonia. In this study, we present a small-sized and ultrasensitive accelerometer for continuous monitoring of lung and heart sounds to evaluate the lung and heart states of patients. Based on two-stage amplification, which consists of an asymmetric gapped cantilever and a charge amplifier, our accelerometer exhibited an extremely high ratio of sensitivity to noise compared with conventional structures. Our sensor achieves a high sensitivity of 9.2 V/g at frequencies less than 1000 Hz, making it suitable to use to monitor weak physiological signals, including heart and lung sounds. For the first time, lung injury, heart injury, and both lung and heart injuries in discharged pneumonia patients were revealed by our sensor device. Our sound sensor also successfully tracked the recovery course of the discharged pneumonia patients. Over time, the lung and heart states of the patients gradually improved after discharge. Our observations were in good agreement with clinical reports. Compared with conventional medical instruments, our sensor device provides rapid and highly sensitive detection of lung and heart sounds, which greatly helps in the evaluation of lung and heart states of pneumonia patients. This sensor provides a cost-effective alternative approach to the diagnosis and prognosis of pneumonia and has the potential for clinical and home-use health monitoring.

14.
Nanomaterials (Basel) ; 9(10)2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31546659

RESUMO

Oxygen ions' migration is the fundamental resistive switching (RS) mechanism of the binary metal oxides-based memristive devices, and recent studies have found that the RS performance can be enhanced through appropriate oxygen plasma treatment (OPT). However, the lack of experimental evidence observed directly from the microscopic level of materials and applicable understanding of how OPT improves the RS properties will cause significant difficulties in its further application. In this work, we apply scanning probe microscope (SPM)-based techniques to study the OPT-enhanced RS performance in prototypical HfOx based memristive devices through in situ morphology and electrical measurements. It is first found that the structural deformations in HfOx nanofilm induced by migration of oxygen ions and interfacial electrochemical reactions can be recovered by OPT effectively. More importantly, such structural deformations no longer occur after OPT due to the strengthening in lattice structure, which directly illustrates the enhanced quantity of HfOx nanofilm and the nature of enhanced RS properties after OPT. Finally, the underlying mechanisms of OPT-enhanced RS performance are analyzed by the results of X-ray photoelectron spectroscopic (XPS) surface analysis. In the OPT-enhanced HfOx nanofilm, oxygen vacancies in crystalline regions can be remarkably reduced by active oxygen ions' implantation. The oxygen ions transport will depend considerably on the grain boundaries and OPT-enhanced lattice structure will further guarantee the stability of conductive filaments, both of which ensure the uniformity and repeatability in RS processes. This study could provide a scientific basis for improving RS performance of oxides-based memristive devices by utilizing OPT.

15.
RSC Adv ; 9(61): 35499-35508, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-35528067

RESUMO

Polar metals, commonly defined by the coexistence of polar structure and metallicity, are thought to be scarce because free carriers eliminate internal dipoles that may arise owing to asymmetric charge distributions. By using first-principle electronic structure calculations, we explored the possibility of producing metallic states in the polar/nonpolar KNbO3/BaTiO3 superlattice (SL) composed of two prototypical ferroelectric materials: BaTiO3 (BTO) and KNbO3 (KNO). Two types of polar/nonpolar interfaces, p-type (KO)-/(TiO2)0 and n-type (NbO2)+/(BaO)0, which can be constituted into two symmetric NbO2/BaO-NbO2/BaO (NN-type) and KO/TiO2-KO/TiO2 (PP-type) SL, as well as one asymmetric KO/TiO2-NbO2/BaO (PN-type) SL. The spatial distribution of ferroelectric distortions and their conductive properties are found to be extraordinarily sensitive to the interfacial configurations. An insulator-to-metal transition is found in each unit cell of the symmetric interfacial SL models: one exhibiting quasi-two-dimensional n-type conductivity for NN-type SL, while the other being quasi-two-dimensional p-type conductivity for PP-type SL. The anisotropic coexistence of in-plane orientation of free carriers and out-of-plane orientation of ferroelectric polarization in KNO/BTO SL indicates that in-plane free carriers can not eliminate the out-of-plane dipoles. Our results provide a road map to create two-dimensional polar metals in insulating perovskite oxide SL, which is expected to promote applications of new quantum devices.

16.
Materials (Basel) ; 12(14)2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31373301

RESUMO

High-throughput production of highly efficient photocatalysts for hydrogen evolution remains a considerable challenge for materials scientists. Here, we produced extremely uniform high-quality graphene and molybdenum disulfide (MoS2) nanoplatelets through the electrochemical-assisted liquid-phase exfoliation, out of which we subsequently fabricated MoS2/graphene van der Waals heterostructures. Ultimately, zinc oxide (ZnO) nanoparticles were deposited into these two-dimensional heterostructures to produce an artificial ZnO/MoS2/graphene nanocomposite. This new composite experimentally exhibited an excellent photocatalytic efficiency in hydrogen evolution under the sunlight illumination ( λ > 400   n m ), owing to the extremely high electron mobilities in graphene nanoplatelets and the significant visible-light absorptions of MoS2. Moreover, due to the synergistic effects in MoS2 and graphene, the lifetime of excited carriers increased dramatically, which considerably improved the photocatalytic efficiency of the ZnO/MoS2/graphene heterostructure. We conclude that the novel artificial heterostructure presented here shows great potential for the high-efficient photocatalytic hydrogen generation and the high throughput production of visible-light photocatalysts for industrial applications.

17.
Nanoscale Res Lett ; 14(1): 121, 2019 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-30941603

RESUMO

Bi3.15Nd0.85Ti2.99Mn0.01O12 (BNTM) thin films with (200)-orientations, (117)-orientations, and mixed-orientations were prepared by sol-gel methods. The influence of orientations on polarization fatigue behaviors of BNTM thin films were systematically investigated at both low and elevated temperatures. It was found that the changed trends of the polarization fatigue of (200)-oriented and (117)-oriented BNTM thin films at elevated temperatures were opposite. The fatigue properties become exacerbated for the (200)-oriented ones and become improved for the (117)-oriented ones, while the reduction of remanent polarization first decreases and then increases for the mixed-oriented ones. It can be assumed that the different roles played by domain walls and interface layer with increasing T in these thin films have caused such differences, which was certified by the lower activation energies (0.12-0.13 eV) of (200)-oriented BNTM thin films compared to those of BNTM thin films (0.17-0.31 eV) with other orientations through the temperature-dependent impedance spectra analysis. With the aid of piezoresponse force microscopy (PFM), the non-neutral tail-to-tail or head-to-head polarization configurations with greater probabilities for (117)-oriented and mixed-oriented thin films were found, while a majority of the neutral head-to-tail polarization configurations can be observed for (200)-oriented ones.

18.
Materials (Basel) ; 11(12)2018 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-30501084

RESUMO

Bi4Ti2.99Mn0.01O12 (BTM) thin films with different ratio of neodymium (Nd) doping were prepared on Pt(111)/Ti/SiO2/Si(100) substrates through a sol-gel method. The effects of Nd doping on domain dynamics and temperature-dependent fatigue behaviors of BTM thin films were systematically studied. The polarization fatigues of BTM (not doped) and Bi3.5Nd0.5Ti2.99Mn0.01O12 (BNTM05) thin films first get better with the increasing temperature (T) from 300 to 350 K and then become worse from 350 to 400 K, while Bi3.15Nd0.85Ti2.99Mn0.01O12 (BNTM85) thin films show enhanced fatigue endurance from 300 to 400 K. It can be shown that the long-range diffusion of oxygen vacancies in BTM thin film happens more easily through the impedance spectra analysis with T from 300 to 475 K, which can be verified by a lower activation energies (0.13⁻0.14 eV) compared to those of BNTM05 and BNTM85 (0.17⁻0.21 eV). Using a temperature-dependent piezoresponse force microscopy (PFM), we have found more responsive domain fragments in Nd-substituted films. The microscopic domain evolution from 298 to 448 K was done to further explain that the domain wall unpinning effect has been enhanced with increasing T. The correlation between microscopic domain dynamics and macroscopic electrical properties clearly demonstrates the effects of charged domain wall in Nd-doped BTM thin films during the fatigue tests.

19.
Zhonghua Wai Ke Za Zhi ; 45(2): 118-20, 2007 Jan 15.
Artigo em Zh | MEDLINE | ID: mdl-17418041

RESUMO

OBJECTIVE: To study the etiology and preventive measures of the long-term postoperative complication after esophageal replacement with colon for esophageal benign disease. METHODS: To review the clinical data of 577 patients with esophageal replacement with colon our department, including 123 cases of esophageal benign disease. Of all, there were 25 cases-time for 11 cases following with severe complication: redundancy and dilated colon 12 cases-time, severe stricture of stoma 4, macrocyst esophagus 2, colon-stomach stoma expansion 4, mechanical obstruction of colon 3. The etiology included iatrogenic and functionality. The therapy included stricture form or resection, redundancy segment resection, obstructed segment solution and stoma resection and form. RESULTS: Eight cases underwent once operation, 2 case twice, 1 case three times. After operation, 9 cases took food normally, 2 improved symptoms obviously. CONCLUSIONS: The iatrogenic and functionality factor contributed to severe complication after esophageal replacement with colon for esophageal benign disease. The preventive measure is followed during operation: cervical esophageal-colon anastomosis exceed 2.5 centimeter, abdominal colon-stomach anastomosis reflux, channel width of colon passage, intestinal canal lay up straight. Re-operation is best choice to for local stricture, colon expansion, redundancy and dilated colon.


Assuntos
Colo/cirurgia , Doenças do Esôfago/cirurgia , Esofagoplastia/efeitos adversos , Complicações Pós-Operatórias/etiologia , Adulto , Esofagoplastia/métodos , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/prevenção & controle , Complicações Pós-Operatórias/cirurgia , Reoperação , Estudos Retrospectivos
20.
Zhonghua Yi Xue Za Zhi ; 86(21): 1453-6, 2006 Jun 06.
Artigo em Zh | MEDLINE | ID: mdl-16842695

RESUMO

OBJECTIVE: To investigate the configuration of colic vessels in Chinese and its influence on the operation of esophageal replacement with colon (ERC). METHODS: The origin, trend, branching, configuration, and distribution of the colic vessels, the intensity of the colic arterial impulse, the integrity of the marginal artery at the splenic flexure and hepatic flexure of colon were observed during the operation of ERC among 582 patients undergoing ERC, 402 males mad 180 females, aged 2 approximately 74, from 22 provinces, municipality, and autonomous regions. RESULTS: The left colic artery (LCA) stemmed from the inferior mesenteric artery (IMA) in 97.3% of the patients, with an absence rate of 0.7%. The middle colic artery (MCA) stemmed from the superior mesenteric artery (SMA) in 77.8% of the patients with an absence rate of 8.2%. Accessory middle colic artery (acMCA), originating from the right colic artery, could be seen in 6.2% of the patients 39.7% of the right colic artery (RCA) stemmed from the SMA by itself, 23.0% of the RMA stemmed together with MCA, and 28.0% of the RCA stemmed together with the ileocolic artery. The absence rate of RCA was 9.8%. The intactness rate of marginal artery was 96.8% at the splenic flexure of colon, and was 88.7% at the hepatic flexure. The Rolan arch was seen in only 7.6% of the patients. CONCLUSION: The configuration of colic vessels in Chinese was basically similar to those of the results of autopsies carried out abroad. The optimal supply artery of colic segment during ERC is LCA, followed by LCA. Attention should be paid to the integrity of marginal arteries and veins in the patients with history of epigastric operation.


Assuntos
Colo/irrigação sanguínea , Colo/cirurgia , Neoplasias Esofágicas/cirurgia , Esofagoplastia/métodos , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Gástricas/cirurgia
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