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1.
Nanoscale ; 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32020142

RESUMO

A mechanistic understanding of perovskite degradation is one of the most urgent issues to push perovskite devices toward commercial applications. Surface coverings will lower the electrical injection and light extraction efficiency of perovskites. Therefore, structural modification of Zn doped perovskites has been proposed herein. The Zn doping will induce local lattice strain due to smaller ionic radius. It is interesting that the lattice structure at atomic resolution has been observed directly through cryo-TEM. Under light illumination, the photostriction will compensate for the local lattice strain, which leads to structural stability as evidence suggests no phase transition in temperature ranges of the temperature-dependent photoluminescence spectra. In addition, MPZB also shows less than 3% decrease in PL intensity after 60 days. This is because the Zn doping induced the lowest defect density in the MPZB SC (density of trap-states ntrp = 6.33 × 108 cm-3), which has been confirmed by the high performance of the photodetector. Such strain compensation is expected to fundamentally improve the stability of photoelectric devices.

2.
Life Sci ; 246: 117428, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32057901

RESUMO

PURPOSE: Arl4c is overexpressed in several cancer tissues and is involved in cancer development. Nevertheless, the exact mechanism that regulates Arl4c expression in lung cancer has not been fully elucidated. The aim of this study was to investigate the regulatory mechanism of Arl4c and to explore potential chemotherapeutic drugs targeting Arl4c. METHODS: Immunohistochemistry was used to examine Arl4c expression levels in human lung adenocarcinoma cancer specimens. Protein expression was detected by western blot. Overexpression of Arl4c-Flag protein was used to detect the ubiquitination of Arl4c. A short interfering RNA against Arl4c was used for gene silencing. RESULTS: Arl4c was overexpressed in lung cancer tissues, and knockdown of Arl4c expression by siRNA decreased lung cancer A549 and 95-D cell proliferation. In addition, Arl4c expression was downregulated via inhibition of the AKT pathway in A549 and 95-D cells, whereas exposure to benzo (a) pyrene (a carcinogen in smoke) increased Arl4c expression in 16HBE cells via AKT activation. Finally, we found that chemotherapy drug hydroxycamptothecin (HCPT) could decrease Arl4c expression levels by inhibiting the activation of the AKT pathway in A549 and 95-D cells. Moreover, accumulation of ubiquitinated Arl4c protein was increased by HCPT and LY294002 (an AKT inhibitor) treatment whereas the proteasome inhibitor MG-132 attenuated the inhibitory effect of HCPT and LY294002 on Arl4c expression. CONCLUSION: Here, we highlighted the AKT pathway as an important regulatory pathway for Arl4c expression in lung cancer cells and identified HCPT as a promising drug for lung adenocarcinoma treatment that functioned by targeting Arl4c expression.


Assuntos
Fatores de Ribosilação do ADP/metabolismo , Adenocarcinoma de Pulmão/metabolismo , Adenocarcinoma/metabolismo , Neoplasias Pulmonares/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Células A549 , Western Blotting , Camptotecina/análogos & derivados , Camptotecina/farmacologia , Linhagem Celular Tumoral , Cromonas/farmacologia , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Leupeptinas/farmacologia , Morfolinas/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Fumar/efeitos adversos
3.
Nat Commun ; 10(1): 5589, 2019 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-31811122

RESUMO

Excitons in two-dimensional (2D) materials are tightly bound and exhibit rich physics. So far, the optical excitations in 2D semiconductors are dominated by Wannier-Mott excitons, but molecular systems can host Frenkel excitons (FE) with unique properties. Here, we report a strong optical response in a class of monolayer molecular J-aggregates. The exciton exhibits giant oscillator strength and absorption (over 30% for monolayer) at resonance, as well as photoluminescence quantum yield in the range of 60-100%. We observe evidence of superradiance (including increased oscillator strength, bathochromic shift, reduced linewidth and lifetime) at room-temperature and more progressively towards low temperature. These unique properties only exist in monolayer owing to the large unscreened dipole interactions and suppression of charge-transfer processes. Finally, we demonstrate light-emitting devices with the monolayer J-aggregate. The intrinsic device speed could be beyond 30 GHz, which is promising for next-generation ultrafast on-chip optical communications.

4.
ACS Appl Mater Interfaces ; 11(46): 43351-43358, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31657205

RESUMO

Graphene-based p-n junction photodiodes have a potential application prospect in photodetection due to their broadband spectral response, large operating bandwidth, and mechanical flexibility. Here, we report an ultraviolet (UV) rewritable p-n junction photodiode in a configuration of graphene coated with an amorphous phosphor of 4-bromo-1,8-naphthalic anhydride derivative polymer (poly-BrNpA). Under moderate UV irradiation, occurrence of photoisomerization reaction in the poly-BrNpA film leads to its drastically modified optical characteristics and a concurrent n-type doping in the underneath graphene. Meanwhile, the poly-BrNpA film, highly sensitive to water molecules, has a capability of restoring graphene to its initial p-type doping status by means of water adsorption. Based on these findings, a lateral graphene/poly-BrNpA p-n junction photodiode, responsive to visible light at the junction interface, can be written by UV irradiation and then erased via water adsorption. The p-n junction photodiode is rewritable upon such repetitive loops showing repeatable optoelectronic properties. This study provides a new scheme and perspective of making graphene-based rewritable p-n junction photodiodes in a flexible and controllable way, and it may contribute to expanding new families of optoelectronic devices based on two-dimensional materials.

5.
Nanoscale ; 11(43): 20707-20714, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31642837

RESUMO

As one of the bismuth-based oxychalcogenide materials, Bi2O2Se ultrathin films have received intense research interest due to their high carrier mobility, narrow bandgaps, ultrafast intrinsic photoresponse and long-term ambient stability; they exhibit great potential in electronic and optoelectronic applications. However, the device performance of photodetectors based on metal/Bi2O2Se/metal structures has degraded due to the undesirable defects or contaminants from the electrode deposition or the sample transfer processes. In this work, highly efficient photodetectors based on Au/Bi2O2Se junctions were achieved with Au electrodes transferred under the assistance of a probe tip to avoid contaminants from traditional lighography methods. Furthermore, to improve the charge transfer efficiency, specifically by increasing the intensity of the electrical field at the Au/Bi2O2Se interface and along the Bi2O2Se channels, the device annealing temperature was optimized to narrow the van der Waals gap at the Au/Bi2O2Se interface and the device channel length was shortened to improve the overall device performance. Among all the devices, the maximum device photoresponsivity was 9.1 A W-1, and the device response time could approach 36 µs; moreover, the photodetectors featured broadband spectral responses from 360 nm to 1090 nm.

6.
Nano Lett ; 19(11): 8132-8137, 2019 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-31556623

RESUMO

Noncontact optical sensing plays an important role in various applications, for example, motion tracking, pilotless automobile, precision machining, and laser radars. A device with features of high resolution, fast response, and safe detection (operation wavelength at infrared (IR)) is highly desired in such applications. Here, a near IR position-sensitive detector constructed by graphene-Ge Schottky heterojunction has been demonstrated. The device shows high responsivity (minimum detectable power of ∼10 nW), excellent spatial resolution (<1 µm), fast response time (∼µs), and could operate in a wide spectral range (from visible to ∼1600 nm). Applications of precise angle (∼5 × 10-6 degree) and vibration frequency (up to 10 kHz) measurements, as well as the trajectory tracking of a high-speed infrared target (∼100 km/h), have been realized based on this device. This work therefore provides a promising route for a high-performance noncontact IR optical sensing system.

7.
Adv Mater ; 31(43): e1903829, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31495984

RESUMO

Interfacial charge transfer is a fundamental and crucial process in photoelectric conversion. If charge transfer is not fast enough, carrier harvesting can compromise with competitive relaxation pathways, e.g., cooling, trapping, and recombination. Some of these processes can strongly affect the speed and efficiency of photoelectric conversion. In this work, it is elaborated that plasmon-induced hot-electron transfer (HET) from tungsten suboxide to graphene is a sufficiently fast process to prevent carrier cooling and trapping processes. A fast near-infrared detector empowered by HET is demonstrated, and the response time is three orders of magnitude faster than that based on common band-edge electron transfer. Moreover, HET can overcome the spectral limit of the bandgap of tungsten suboxide (≈2.8 eV) to extent the photoresponse to the communication band of 1550 nm (≈0.8 eV). These results indicate that plasmon-induced HET is a new strategy for implementation of efficient and high-speed photoelectric devices.

8.
Front Oncol ; 9: 501, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31259152

RESUMO

Paclitaxel (PTX) is widely used as a front-line chemotherapy for breast cancer treatment. However, its clinical applications are limited by the development of chemoresistance. The objective of this study was to investigate the reversal effects of ursolic acid (UA) on PTX resistance and the possible mechanisms in breast cancer. The role of miRNA-149-5p/MyD88 in the regulation of PTX resistance was investigated by the transfection of breast cancer cells with MDA-MB-231 (231) and MDA-MB-231/PTX-resistance (231/PTX) with lentiviruses carrying the MyD88 gene, shRNA specific for MyD88, the miR-149-5p gene, and shRNA specific for miR-149-5p. The PTX sensitivity was assessed by a CCK-8 assay. qRT-PCR and Western blot analyses were used to detect changes in the mRNA and protein levels. Flow cytometry was used to measure the rate of cell apoptosis. A luciferase activity assay was used to detect the binding site of miR-149-5p on the 3'UTR of MyD88. 231/PTX cells were injected into the flanks of female athymic nude mice, and the mice were randomly divided into the five following groups: PBS, PTX (low), PTX (high), UA, and PTX+UA. Our data show that UA reversed the resistance of breast cancer 231/PTX cells to PTX in vitro and in vivo. UA treatment significantly increased the expression of miR-149-5p, which was lower in 231/PTX cells than in 231 cells. Furthermore, the overexpression of miR-149-5p increased the sensitivity of 231/PTX cells to PTX treatment, whereas the knockdown of the miR-149-5p gene attenuated the effects of UA on the regulation of PTX sensitivity. A luciferase assay demonstrated that miR-149-5p could directly regulate the transcriptional activity of MyD88, a known PTX-resistance gene, by targeting the 3'UTR of MyD88. Meanwhile, the downregulation of MyD88 through the overexpression of miR-149-5p or UA treatment inhibited the activation of the Akt signaling pathway in 231/PTX cells. Thus, our data indicate that UA can reverse PTX resistance by targeting the miRNA-149-5p/MyD88 axis in breast cancer cells.

9.
Nanoscale Res Lett ; 14(1): 216, 2019 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-31240461

RESUMO

In this report, comparative investigation of photoluminescence (PL) characteristics of CdS nanobelts (NBs) and nanowires (NWs) is presented. At low temperatures, emissions originate from radiative recombination of free exciton A, neutral donor bound exciton, neutral acceptor bound exciton and surface related exciton (SX) are observed and analyzed through power-dependent and temperature-dependent PL measurements. We found that SX emission takes a predominant role in emissions of CdS nanobelts and nanowires. There is a direct correlation between SX emission intensity and surface-to-volume ratio, which is the SX emission intensity is proportional to the superficial area of the nanostructures. At the same time, we found that the exciton-phonon interaction in the CdS NWs sample is weaker than that of CdS NBs sample. Furthermore, lasing action has been observed in CdS NBs sample at room temperature with lasing threshold of 608.13 mW/cm2. However, there is no lasing emission in CdS NWs sample. This phenomenon can be explained by the side effects (such as thermal effects) from surface deep level transitions caused the lower damage threshold in CdS NWs. Based on the observations and deductions presented here, SX emission significantly impact on the performance of nanostructures for lasing and light-emitting applications.

10.
Nat Commun ; 10(1): 2815, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31249298

RESUMO

Atomically thin hexagonal boron nitride (h-BN) is often regarded as an elastic film that is impermeable to gases. The high stabilities in thermal and chemical properties allow h-BN to serve as a gas barrier under extreme conditions. Here, we demonstrate the isolation of hydrogen in bubbles of h-BN via plasma treatment. Detailed characterizations reveal that the substrates do not show chemical change after treatment. The bubbles are found to withstand thermal treatment in air, even at 800 °C. Scanning transmission electron microscopy investigation shows that the h-BN multilayer has a unique aligned porous stacking nature, which is essential for the character of being transparent to atomic hydrogen but impermeable to hydrogen molecules. In addition, we successfully demonstrated the extraction of hydrogen gases from gaseous compounds or mixtures containing hydrogen element. The successful production of hydrogen bubbles on h-BN flakes has potential for further application in nano/micro-electromechanical systems and hydrogen storage.

11.
Nanotechnology ; 30(29): 295704, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-30965309

RESUMO

We present a simple, but rapid and accurate approach to identify the layer number of graphene oxide (GO) by using its thermally enhanced optical contrast via vacuum heating. As expected, changes have been observed both in the thicknesses and chemical structures of the material upon the thermal treatment, which can be attributed to the reduction of the amount of intercalated water and oxygen content. This results in the increase of refractive index and absorption coefficient approaching the values for intrinsic graphene. Finally, we achieve an almost complete recovery of optical contrast of GO compared with the one of graphene. The method would be made suitable for the thickness identification of mass-produced GO since it can greatly facilitate sample evaluation and manipulation, and provide immediate feedback to improve synthesis and processing strategies.

12.
Chin J Nat Med ; 17(3): 198-208, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30910056

RESUMO

Resistance to cisplatin (DDP)-based chemotherapy is a major cause of treatment failure in human gastric cancer (GC). It is necessary to identify the drugs to re-sensitize GC cells to DDP. In our previous research, Zuo Jin Wan Formula (ZJW) has been proved could increase the mitochondrial apoptosis via cofilin-1 in a immortalized cell line, SGC-7901/DDP. Due to the immortalized cells may still difficult highly recapitulate the important molecular events in vivo, primary GC cells model derived from clinical patient was constructed in the present study to further evaluate the effect of ZJW and the underlying molecular mechanism. Immunofluorescent staining was used to indentify primary cultured human GC cells. Western blotting was carried out to detect the protein expression. Cell Counting Kit-8 (CCK-8) was used to evaluate cell proliferation. Flow cytometry analysis was performed to assess cell apoptosis. ZJW inhibited proliferation and induced apoptosis in primary DDP-resistant GC cells. Notably, the apoptosis in GC cells was mediated by inducing cofilin-1 mitochondrial translocation, down-regulating Bcl-2 and up-regulating Bax expression. Surprisingly, the level of p-AKT protein was higher in DDP-resistant GC cells than that of the DDP-sensitive GC cells, and the activation of AKT could attenuate ZJW-induced sensitivity to DDP. These data revealed that ZJW can increase the chemosensitivity in DDP-resistant primary GC cells by inducing mitochondrial apoptosis and AKT inactivation. The combining chemotherapy with ZJW may be an effective therapeutic strategy for GC chemoresistance patients.


Assuntos
Cisplatino/uso terapêutico , Cofilina 1/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Neoplasias Gástricas/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cisplatino/farmacologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Células Tumorais Cultivadas
13.
Cancer Manag Res ; 11: 1069-1080, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30774435

RESUMO

Background/aim: Gastric cancer (GC) is one of a most threatening cancer globally. Rhotekin (RTKN), a Rho effector, has been reported to be upregulated in GC tissues. This study aimed to investigate the underlying regulatory roles of RTKN in the biological behavior of GC. Methods: Real-time PCR and Western blotting were carried out to detect the mRNA and protein expression, respectively. Cell Counting Kit-8 and xenograft nude mice model were used to evaluate cell proliferation. Flow cytometry analysis was performed to assess cell cycle distribution and cell apoptosis. Results: RTKN had high expression level in GC compared with normal tissues. RTKN expression strongly associated with tumor size, TNM stage, lymphnode metastasis and the poor prognosis of patients with GC. Downregulation of RTKN significantly repressed GC cell proliferation, but increased cell population in G1/S phase and induced cell apoptosis. Moreover, the RTKN expression level was related to the p53 signaling pathway and histone deacetylase (HDAC) Class I pathway. RTKN knockdown caused a notable increment in the acetylation level of p53 (Lys382), and the expression of p53-target genes (p21, Bax, and PUMA), as well as a reduction in the expression of a potential deacetylase for p53, HDAC1. Notably, downregulation of HDAC1 had similar effects as RTKN knockdown, and RTKN overexpression could hardly abrogate the effects of HDAC1 knockdown on GC cells. Conclusion: RTKN could work as an oncogene via regulating HDAC1/p53 and may become a promising treatment strategy for GC.

14.
Nat Commun ; 10(1): 598, 2019 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-30723204

RESUMO

Epitaxial growth of atomically thin two-dimensional crystals such as transition metal dichalcogenides remains challenging, especially for producing large-size transition metal dichalcogenides bilayer crystals featuring high density of states, carrier mobility and stability at room temperature. Here we achieve in epitaxial growth of the second monolayer from the first monolayer by reverse-flow chemical vapor epitaxy and produce high-quality, large-size transition metal dichalcogenides bilayer crystals with high yield, control, and reliability. Customized temperature profiles and reverse gas flow help activate the first layer without introducing new nucleation centers leading to near-defect-free epitaxial growth of the second layer from the existing nucleation centers. A series of bilayer crystals including MoS2 and WS2, ternary Mo1-xWxS2 and quaternary Mo1-xWxS2(1-y)Se2y are synthesized with variable structural configurations and tunable electronic and optical properties. The robust, potentially universal approach for the synthesis of large-size transition metal dichalcogenides bilayer single crystals is highly-promising for fundamental studies and technological applications.

15.
Nanotechnology ; 30(18): 184001, 2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-30669129

RESUMO

Rhenium disulfide (ReS2) is an interesting kind of transition metal dichalcogenide (TMD) because of its thickness-independent and suitable direct-bandgap structure, which could enable highly efficient solar-energy conversion efficiency. Here, we demonstrate an ultrasonic liquid exfoliation technique in combination with grinding to produce high quality ReS2 nanosheets (NSs) on a large scale. After combination with TiO2 nanoparticles, the co-catalytic performance of TiO2@ReS2 nanocomposites is investigated, which presents dramatically enhanced degradation activity of organic pigments under sunlight illumination in comparison with pure TiO2 nanoparticles. The underlying mechanism of enhanced photocatalytic activity can be attributed to improved separation efficiency of photogenerated electron-hole pairs in TiO2@ReS2 nanocomposites, which is confirmed by photoluminescence analysis and photoelectrochemical measurements. Our results demonstrate that the layered ReS2 NS is a promising two-dimensional supporting platform for photocatalysis and moreover it could also provide a new perspective on TMDs co-catalyst.

16.
Nanotechnology ; 30(3): 034004, 2019 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-30452391

RESUMO

Phase transition from the semiconducting hexagonal (2H) phase to the metallic monoclinic (1T') phase in two-dimensional (2D) transition metal dichalcogenides like MoTe2 is not only of great importance in fundamental study but also of technological significance for broad device applications. Here we report a universal, facile, scalable and reversible phase engineering technique (between 2H and 1T' phases) for both monolayer and few-layer MoTe2 based on a soft hydrogen plasma treatment. The 2H â†’ 1T' transition was confirmed by a series of characterizations including Raman spectra and mapping studies, XPS analysis and FET device measurements at varying temperatures. We attribute the phase transition to the warping of Te-Mo bonds and the lateral sliding of the top Te-layer induced by the soft hydrogen ion bombardment according to both the structural and electronic characterizations as well as the horizontal comparison with the cases of Ar or O2 plasma treatment. We have also prepared a 2D heterostructure containing periodical 2H and 1T' MoTe2 and showed that such phase transition can be readily reversed by post annealing. These results thus provide a robust and efficient approach for the phase engineering of monolayer and few-layer MoTe2 and could aid the development of 2D optoelectronic, memory and reconfigurable devices.

17.
ACS Appl Mater Interfaces ; 10(45): 39187-39193, 2018 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-30295018

RESUMO

Ferroelectric thin films are extensively attractive as next-generation nonvolatile memories. Recently, molecular ferroelectrics (MFe), as an emerging new class, have been a new research focus because of their desirable characteristics such as good solution processability, tunable chemical properties, and bio-friendly compositions. However, traditional uniaxial MFe only possess one polar axis which greatly limits their application, as it requires restricted orientational control in single crystal. To achieve macroscopic ferroelectricity and thus fully realize technological advantages of MFe, development of multiaxes is imperative to maximize effective polarization in specific crystallographic orientations. Herein, we present an early exploration on polycrystalline multiaxial MFe thin films of [Hdabco][ReO4] with a two-dimensional graphene hybrid nonvolatile memory device. The polarization switching of MFe is experimentally realized by the nonvolatile modulation of two current states in graphene. Such a hybrid device can exhibit large memory window ∼35 V implying its great potential in memory applications. Hence, by taking the advantages of multiple polarization axes of MFe, the low cost and large area MFe/graphene hybrid memory manifests new possibilities for the integration of these materials as flexible next generation memory devices.

18.
Adv Mater ; : e1804332, 2018 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-30168633

RESUMO

Defect-induced trap states are essential in determining the performance of semiconductor photodetectors. The de-trap time of carriers from a deep trap can be prolonged by several orders of magnitude as compared to shallow traps, resulting in additional decay/response time of the device. Here, it is demonstrated that the trap states in 2D ReS2 can be efficiently modulated by defect engineering through molecule decoration. The deep traps that greatly prolong the response time can be mostly filled by protoporphyrin molecules. At the same time, carrier recombination and shallow traps in-turn play dominant roles in determining the decay time of the device, which can be several orders of magnitude faster than the as-prepared device. Moreover, the specific detectivity of the device is enhanced (as high as ≈1.89 × 1013 Jones) due to the significant reduction of the dark current through charge transfer between ReS2 and molecules. Defect engineering of trap states therefore provides a solution to achieve photodetectors with both high responsivity and fast response.

19.
Exp Ther Med ; 16(4): 3121-3128, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30214535

RESUMO

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease. It is asymptomatic at presentation and is frequently identified among individuals with metabolic dysfunction, including obesity and diabetes. NAFLD is primarily characterized by the accumulation of triacylglycerol in the liver. Since insulin resistance and fat metabolism dysregulation are major causes of type 2 diabetes and NAFLD, anti-diabetes agents are widely considered as potential therapy strategies for NAFLD. Sitagliptin, an inhibitor of dipeptidyl peptidase-4, has been developed as an oral anti-hyperglycemic agent. In the present study, the effect of sitagliptin on the progression of NAFLD was evaluated in a rat model fed with a high fat diet (HFD). It was identified that sitagliptin significantly suppressed lipid accumulation in rat blood and liver and improved insulin resistance. Furthermore, it was revealed that sitagliptin reactivated the HFD-suppressed SIRT1/AMPK axis pathway and upregulated its downstream target genes, modulating fatty acid metabolism. These findings demonstrate a preventive effect of sitagliptin on hepatic lipid dysregulation and suggest that sitagliptin has potential as a clinical therapeutic strategy for NAFLD.

20.
Phys Chem Chem Phys ; 20(38): 25078-25084, 2018 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-30250949

RESUMO

Two transparent graphene-metal nanoparticle (NP) hybrid schemes, namely Au NPs covered by graphene layers and Au NPs encapsulated by graphene layers, are presented and the effect of graphene on the localized surface plasmon resonance of metal NPs is systematically investigated. For both schemes, the direct contact of graphene with Au NPs would strongly tune the resonant frequency due to the electron transfer from Au NPs to graphene. Such electron transfer is demonstrated by comparing the absorption spectra of Au NPs with different free electron densities between calculation results via FDTD simulation and experimental results, comparing Raman properties of graphene between pure graphene and the Au-NP/graphene hybrid nanostructure, correlating the electron doping concentration in graphene with the electron density change in Au NPs, and ruling out the possible mechanism of the change of the effective refractive index of Au NPs. Such an effective tuning of the resonant frequency may shed light on the future applications of 2D based materials in plasmonic devices.

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