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2.
ACS Nano ; 15(9): 15047-15056, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34529415

RESUMO

Lithium-sulfur (Li-S) batteries have attracted widespread attention due to their high theoretical energy density. However, their practical application is still hindered by the shuttle effect and the sluggish conversion of lithium polysulfides (LiPSs). Herein, monodisperse molybdenum (Mo) nanoparticles embedded onto nitrogen-doped graphene (Mo@N-G) were developed and used as a highly efficient electrocatalyst to enhance LiPS conversion. The weight ratio of the electrocatalyst in the catalyst/sulfur cathode is only 9%. The unfilled d orbitals of oxidized Mo can attract the electrons of LiPS anions and form Mo-S bonds during the electrochemical process, thus facilitating fast conversion of LiPSs. Li-S batteries based on the Mo@N-G/S cathode can exhibit excellent rate performance, large capacity, and superior cycling stability. Moreover, Mo@N-G also plays an important role in room-temperature quasi-solid-state Li-S batteries. These interesting findings suggest the great potential of Mo nanoparticles in building high-performance Li-S batteries.

3.
Nanotechnology ; 32(50)2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34488214

RESUMO

Tungsten Disulfide (WS2) films, as one of the most attractive members in the family of transition metal dichalcogenides, were synthesized typically on SiO2/Si substrate by confine-spaced chemical vapor deposition method. The whole process could be controlled efficiently by precursor concentration and fast thermal process. To be priority, the effect of fast heating-up to cooling-down process and source ratio-dependent rule for WS2structure have been systematically studied, leading to high-yield and fine structure of monolayer WS2films with standard triangular morphology and average edge length of 92.4µm. The growth time of the samples was regulated within 3 min, and the optimal source ratio of sulfur to tungsten oxide is about 200:3. The whole experimental duration was about 50 min, which is only about quarter in comparison to relevant reports. We assume one type of 'multi-nucleation dynamic process' to provide a potential way for fast synthesis of the samples. Finally, the good performance of as-fabricated field-effect transistor on WS2film was achieved, which exhibits high electron mobility of 4.62 cm2V-1s-1, fast response rate of 42 ms, and remarkable photoresponsivity of 3.7 × 10-3A W-1. Our work will provide a promising robust way for rapid synthesis of high-quality monolayer TMDs films and pave the way for the potential applications of TMDCs.

4.
J Biomed Nanotechnol ; 17(7): 1380-1391, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34446141

RESUMO

Esophageal cancer is one of the most common human malignancies and ranks sixth for global mortality; the major histological type is esophageal squamous cell carcinoma (ESCC). Here we assessed the effect of long non-coding (lnc) RNA OIP5-AS1 on the miR-30a-5p/Forkhead box protein D1 (FOXD1) axis in ESCC and investigated the underlying mechanism involving the ERK1/2 signaling pathway. lnc RNA OIP5-AS1 was highly expressed in human ESCC tissues and cells, targeted miR-30a-5p, and inhibited miR-30a-5p expression. Additionally, in human ESCC tissues, miR-30a-5p was poorly expressed, whereas FOXD1 mRNA and protein were highly expressed, with a negative correlation between miR-30a-5p and FOXD1 expression. miR-30a-5p targeted and inhibited FOXD1 expression. FOXD1 promoted the proliferation and invasion of ESCC and was related to the ERK1/2 signaling pathway; ERK1/2 inhibitors (LY-3214996) reversed the biological function of FOXD1. miR-30a-5p combined with FOXD1 regulated ERK1/2 expression and inhibited tumor growth in vivo. In this study, micro- and nano-particles were used as carriers to construct Nanocapsules carrying miR-30a-5p mimics and miR-30a-5p inhibitor through self-assembly method, so as to realize an efficient Nanocapsules delivery system of miR-30a-5p to esophageal cancer cells. It provides insights into targeted drug therapy and the development of micro- and nano-particles carriers.


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Neoplasias de Cabeça e Pescoço , MicroRNAs , RNA Longo não Codificante , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/genética , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , MicroRNAs/genética , RNA Longo não Codificante/genética , Transfecção
5.
BMC Cancer ; 21(1): 666, 2021 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-34088283

RESUMO

BACKGROUND: Early-stage non-small lung cancer patients may survive long enough to develop second primary lung cancers. However, few studies have accurately described the therapeutic method, evaluation or prognostic factors for long-term survival in this complex clinical scenario. METHODS: Patients who had first and second primary non-small lung cancer in the Surveillance, Epidemiology, and End Results database between 2004 and 2015 were evaluated. Patients were included when their tumors were pathologically diagnosed as non-small lung cancer and in the early-stage (less than 3 cm and with no lymph node metastasis). Therapeutic methods were categorized as lobectomy, sublobectomy or no surgery. The influence of different therapeutic methods on the overall survival rate was compared. RESULTS: For the first primary tumor, patients who underwent lobectomy achieved superior survival benefits compared with patients who underwent sublobectomy. For the second primary tumor, long-term survival was similar in patients who underwent lobectomy and those who underwent sublobectomy treatment. The multivariate analysis indicated that age, disease-free time interval, sex, and first and second types of surgery were independent prognostic factors for long-term survival. Our results showed that the 5-year overall survival rate was 91.9% when the disease-free interval exceeded 24 months. CONCLUSION: Lobectomy for the first primary tumor followed by sublobectomy for the second primary tumor may be a beneficial therapeutic method for patients. If the disease-free interval exceeds 24 months, the second primary tumor will have no influence on the natural course for patients diagnosed with a first primary non-small lung cancer.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/terapia , Neoplasias Pulmonares/cirurgia , Recidiva Local de Neoplasia/epidemiologia , Segunda Neoplasia Primária/cirurgia , Pneumonectomia/métodos , Adulto , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/patologia , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Pulmão/patologia , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/prevenção & controle , Estadiamento de Neoplasias , Segunda Neoplasia Primária/diagnóstico , Segunda Neoplasia Primária/mortalidade , Segunda Neoplasia Primária/patologia , Pneumonectomia/estatística & dados numéricos , Prognóstico , Estudos Retrospectivos , Programa de SEER/estatística & dados numéricos , Taxa de Sobrevida , Fatores de Tempo
6.
Research (Wash D C) ; 2020: 5860712, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33029589

RESUMO

Numerous experiments have demonstrated that the metal atom is the active center of monoatomic catalysts for hydrogen evolution reaction (HER), while the active sites of nonmetal doped atoms are often neglected. By combining theoretical prediction and experimental verification, we designed a unique ternary Ru-N4-P coordination structure constructed by monodispersed Ru atoms supported on N,P dual-doped graphene for highly efficient hydrogen evolution in acid solution. The density functional theory calculations indicate that the charge polarization will lead to the most charge accumulation at P atoms, which results in a distinct nonmetallic P active sites with the moderate H∗ adsorption energy. Notably, these P atoms mainly supply highly efficient catalytic sites with ultrasmall absorption energy of 0.007 eV. Correspondingly, the Ru-N4-P demonstrated outstanding HER performance not only in an acidic condition but also in alkaline environment. Notably, the performance of Ru-NPC catalyst at high current is even superior to the commercial Pt/C catalysts, whether in acidic or alkaline medium. Our in situ synchrotron radiation infrared spectra demonstrate that a P-Hads intermediate is continually emerging on the Ru-NPC catalyst, actively proving the nonmetallic P catalytically active site in HER that is very different with previously reported metallic sites.

7.
Nanotechnology ; 31(34): 345704, 2020 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-32375140

RESUMO

Two-dimensional transition metal dichalcogenide (2D TMDs) alloys, consisting of three or more elements, offer a luxury variety of chemical and physical properties through elemental ratio alteration, thus may provide ideal candidate with tunable band gap for specific electrical applications. In this work, we demonstrate a high-quality layered MoSe2xTe2-2x (x = 0 ∼ 1) alloy synthesized via one-step chemical vapor transport method for high-performance electronic and optoelectronic transistors. Our characterizations reveal the obtained ternary alloy forming high-quality single crystal layers with 2H phase. Interestingly, the electronic transistors fabricated on MoSe2xTe2-2x thin layers (6 ∼ 7 layers) display an anomalous transition from ambipolar to n-type in conductive characteristics with the increase of substitution x value. The subsequent photoelectrical measurements exhibit that high on-off ratio for every ratio (x = 0.18, 0.38, 0.67, 0.83) with optical band gap in the range of 1.6 eV and 1.1 eV (near infrared). The optimized MoSe0.37Te1.63-based transistor can achieve up to ∼107 I on/I off and 105 I ph/I dark ratio, 100 mA W-1 photo-responsivity and 2.38% external quantum efficiency with high photoresponsivity. Thus, such ternary MoSe2xTe2-2x alloys may pose a great potential for 2D-based electronic and photoelectronic applications.

8.
J Phys Chem Lett ; 10(20): 6081-6087, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31539474

RESUMO

Rationally designing cheap and efficient electrocatalysts at the atomic level is highly desirable for the hydrogen evolution reaction (HER). Here, we demonstrate a metallic MoS2 electrocatalyst decorated with platinum single atoms. When combined with electron microscopy observations, our synchrotron X-ray characterizations and theoretical calculations clearly reveal that the doped Pt atoms bond to S atoms on the surface of MoS2. Notably, these Pt single atoms serve as critical active centers for the HER through capturing H+ from the solution. The optimized Pt-MoS2 catalysts achieve significantly enhanced HER performance due to the single-atom coordination effect. This finding is expected to facilitate further realization of hybridized catalysts through the monatomic riveting strategy.

9.
Int J Oncol ; 55(5): 1165-1175, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31545422

RESUMO

Tumor metastasis regulated by epithelial­mesenchymal transition (EMT) plays a significant role in the development of human cancers, whereas the molecular mechanisms of this process in head and neck squamous cell carcinoma (HNSCC) remain elusive. In this study, we found that inhibition of enhancer of zeste homolog 2 (EZH2) resulted in suppressed EMT in HNSCC in vitro and in vivo. We reported that signal transducer and activator of transcription factor 3 (STAT3)/vascular endothelial growth factor receptor 2 (VEGFR2) axis served as the downstream signaling of EZH2 and mediated EMT in HNSCC. EZH2 inhibition downregulated the expression of key molecules of the STAT3/VEGFR2 axis and EMT­related markers, while the expression of E­cadherin was upregulated in HNSCC cells. Targeting the EZH2/STAT3/VEGFR2 axis significantly reduced motility of HNSCC cells. Furthermore, EZH2 knockdown reduced the growth of xenograft HNSCC tumors via inhibiting the EZH2/STAT3/VEGFR2 axis. In conclusion, we proposed that EZH2 regulates EMT and tumor invasion and metastasis in HNSCC by governing the STAT3/VEGFR2 axis. These findings provide a rationale for developing novel strategies to treat invasive and metastatic HNSCC via targeting the EZH2/STAT3/VEGFR2 pathway.


Assuntos
Biomarcadores Tumorais/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Transição Epitelial-Mesenquimal , Neoplasias de Cabeça e Pescoço/patologia , Fator de Transcrição STAT3/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Apoptose , Biomarcadores Tumorais/genética , Movimento Celular , Proliferação de Células , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Fator de Transcrição STAT3/genética , Transdução de Sinais , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Células Tumorais Cultivadas , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Ensaios Antitumorais Modelo de Xenoenxerto
10.
ACS Nano ; 13(10): 11733-11740, 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31525961

RESUMO

Molybdenum disulfide (MoS2) has attracted much attention as a promising alternative to Pt-based catalysts for highly efficient hydrogen generation. However, it suffers sluggish kinetics for driving the hydrogen evolution reaction (HER) process because of inert basal planes, especially in alkaline solution. Here, we show a combination of heteroatom doping and phase transformation strategies to engineer the in-plane structure of MoS2, that trigger their catalytic activities. Systematic characterizations are performed with advanced aberration-corrected microscopy and X-ray techniques, indicating that an as-designed MoS2 catalyst has a distorted zigzag-chain superlattice in metallic phase, while its in-plane structure was engineered via the incorporation of cobalt and oxygen species. The optimal Co, O dual-doped metallic phase molybdenum disulfide (1T-MoS2) electrocatalyst shows a significantly enhanced HER activity with a low overpotential of 113 mV at 10 mA cm-2 and corresponding small Tafel slope of 50 mV dec-1, accompanied by the robust stability in alkaline media. The calculated turnover frequency is higher than 6.65 H2 s-1 at an overpotential of 200 mV. More in-depth insights from the first-principle calculations illustrate that the water dissociation as a rate-determining step was largely accelerated by the in-plane Co-O-Mo species and fast electron transfer of the catalyst. Benefiting from ingenious design and fine identifications, this work provides a fundamental understanding of the relationships among heteroatom doping, phase transformation, and performance for MoS2-based catalysts.

11.
Am J Cancer Res ; 9(4): 699-713, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31105997

RESUMO

Aberrant expression and activation of signal transducer and activator of transcription 3 (STAT3) is implicated in several malignancies, including glioblastoma, and is correlated with poor outcomes in patients with glioblastoma, rendering STAT3 a potential therapeutic target. However, few STAT3 inhibitors have been approved for clinical use. We recently developed an orally active small-molecule compound with anti-STAT3 activity, HJC0152. This study aimed to test the effect of this novel drug on glioblastoma cell lines, and provide possibility to improve clinic prognosis of patients with glioblastoma in the future. In the present study, we aimed to determine the effects of HJC0152 on the growth, proliferation, and chemosensitivity of glioblastoma cell lines and xenograft tumors. We found that HJC0152 inactivated STAT3 via inhibiting phosphorylation of the Tyr705 residue. In vitro, HJC0152 suppressed the proliferation and motility of glioblastoma cells, induced apoptosis, and enhanced the chemosensitivity of glioblastoma cells. Furthermore, HJC0152 inhibited the growth of glioblastoma xenograft tumors in vivo. This study provides a rationale for developing HJC0152 as a STAT3-targeting therapy for treating human glioblastoma in the future.

12.
J Phys Chem Lett ; 10(5): 1048-1054, 2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30777440

RESUMO

Ammonia borane (AB) is regarded as a highly promising candidate for chemical hydrogen-storage materials. Developing low-cost yet efficient catalysts for the dehydrogenation of AB is central to achieving hydrogen conversion. Here a heterostructure of Ni/Ni2P nanoparticles deposited on a defective carbon framework for the hydrolysis of AB is developed by elaborately controlling phosphorization conditions. The electronic structure and interfacial interaction of the ternary components are probed by synchrotron-based X-ray absorption fine structure and further simulated via density functional theory. By adjusting the content of Ni and Ni2P in the hetrostructure, the optimized hybrid exhibits catalytic performance of H2 generation from the hydrolysis of AB under ambient conditions with a turnover frequency of 68.3 mol (H2) mol-1 (Cat) min-1 and an activation energy ( Ea) of 44.99 kJ mol-1, implying its high potential as an efficient supplement for noble-metal-based catalysts in hydrogen energy applications.

13.
Nanotechnology ; 30(6): 065102, 2019 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-30543196

RESUMO

Transition metal dichalogenides (TMDCs) with unique layered structures hold promising potential as transducers for photothermal therapy. However, the low photothermal conversion efficiency and poor stability in some cases limit their practical applications. Herein, we demonstrate the fabrication of ultrathin homogeneous hybridized TMDC nanosheets and their use for highly efficient photothermal tumor ablation. In particular, the nanosheets were composed of metallic WSe2 intercalated with polyvinylpyrrolidone (PVP), which was facilely prepared through a solvothermal process from the mixture of selenourea crystals, WCl6 powder along with PVP polymeric nanogel. Our characterizations revealed that the obtained nanosheets exhibited excellent photothermal conversion efficiency, therapeutic demonstration with improved biocompatibility and physiological stability attributing to the combined merits of metallic phase of WSe2 and hydrophilic PVP insertion. Both the histological analysis of vital organs and in vitro/in vivo tests confirmed the nanosheets as actively effective and biologically safe in this phototherapeutic technique. Findings from this non-invasive experiment clearly emphasize the explorable therapeutic efficacy of the layered-based hybrid agents in future cancer treatment planning procedures.


Assuntos
Fármacos Fotossensibilizantes/uso terapêutico , Fototerapia/métodos , Povidona/química , Selênio/química , Tungstênio/química , Animais , Linhagem Celular Tumoral , Feminino , Raios Infravermelhos/uso terapêutico , Camundongos , Camundongos Endogâmicos BALB C , Nanopartículas/química , Neoplasias Experimentais/terapia , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/química , Temperatura , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Micromachines (Basel) ; 9(6)2018 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-30424225

RESUMO

Despite the fact that two-dimensional layered magnetic materials hold immense potential applications in the field of spintronic devices, tunable magnetism is still a challenge due to the lack of controllable synthesis. Herein, high-quality single crystals MPS3 (M= Mn, Fe) of millimeter size were synthesized through the chemical vapor transport method. After systemic structural characterizations, magnetic properties were studied on the bulk MPS3 layers through experiments, along with first principle theoretical calculations. The susceptibilities as well as the EPR results evidently revealed unique isotropic and anisotropic behavior in MnPS3 and FePS3 crystals, respectively. It is worth noting that both of these materials show antiferromagnetic states at measured temperatures. The estimated antiferromagnetic transition temperature is 78 K for bulk MnPS3 and 123 K for FePS3 crystals. The spin polarized density functional theory calculations confirmed that the band gap of the antiferromagnetic states could be generated owing to asymmetric response all over the energy range. The ferromagnetic state in MnPS3 and FePS3 is less stable as compared to the antiferromagnetic state, resulting in antiferromagnetic behavior. Additionally, frequency-dependent dielectric functions for parallel and perpendicular electric field component vectors, along with the absorption properties of MPS3, are thoroughly investigated.

15.
Cancer Lett ; 436: 52-62, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30118844

RESUMO

Aberrant signal transducer and activator of transcription 3 (STAT3) signaling is a critical factor that drives the invasion and metastasis of head and neck squamous cell carcinoma (HNSCC). However, the underlying mechanisms of STAT3 overexpression and regulation of HNSCC metastasis remain unknown. In the current study, we demonstrated that upregulated TGF-ß may promote epithelial-mesenchymal transition (EMT) through STAT3 activation. In addition, we explored the contributions of STAT3 to HNSCC with a specific focus on its transcriptional regulation and its interaction with the long noncoding RNA (lncRNA) metastasis associated lung adenocarcinoma transcript 1 (malat1). Chromatin immunoprecipitation (ChIP) and luciferase reporter assays revealed that STAT3 could bind to the malat1 promoter region and transcriptionally activate malat1 expression; then, malat1 interacted reciprocally with miR-30a, inducing EMT and accelerating HNSCC metastasis. In summary, our discoveries illuminate how aberrant STAT3 activation confers an oncogenic function in HNSCC and therefore may provide a theoretical foundation for STAT3 as a therapeutic target in HNSCC.


Assuntos
Carcinoma de Células Escamosas/genética , Regulação Neoplásica da Expressão Gênica/genética , Neoplasias de Cabeça e Pescoço/genética , MicroRNAs/genética , RNA Longo não Codificante/genética , Fator de Transcrição STAT3/genética , Animais , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Epistasia Genética , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HEK293 , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/metabolismo , Humanos , Camundongos Endogâmicos BALB C , Camundongos Nus , MicroRNAs/metabolismo , Interferência de RNA , RNA Longo não Codificante/metabolismo , Fator de Transcrição STAT3/metabolismo , Fator de Crescimento Transformador beta/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
16.
Adv Mater ; 30(32): e1802525, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29939441

RESUMO

With the unique-layered structure, MXenes show potential as electrodes in energy-storage devices including lithium-ion (Li+ ) capacitors and batteries. However, the low Li+ -storage capacity hinders the application of MXenes in place of commercial carbon materials. Here, the vanadium carbide (V2 C) MXene with engineered interlayer spacing for desirable storage capacity is demonstrated. The interlayer distance of pristine V2 C MXene is controllably tuned to 0.735 nm resulting in improved Li-ion capacity of 686.7 mA h g-1 at 0.1 A g-1 , the best MXene-based Li+ -storage capacity reported so far. Further, cobalt ions are stably intercalated into the interlayer of V2 C MXene to form a new interlayer-expanded structure via strong V-O-Co bonding. The intercalated V2 C MXene electrodes not only exhibit superior capacity up to 1117.3 mA h g-1 at 0.1 A g-1 , but also deliver a significantly ultralong cycling stability over 15 000 cycles. These results clearly suggest that MXene materials with an engineered interlayer distance will be a rational route for realizing them as superstable and high-performance Li+ capacitor electrodes.

17.
Small ; 14(19): e1800128, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29635871

RESUMO

Developing efficient and low-cost defective carbon-based catalysts for the oxygen reduction reaction (ORR) is essential to metal-air batteries and fuel cells. Active sites engineering toward these catalysts is highly desirable but challenging to realize boosted catalytic performance. Herein, a sandwich-like confinement route to achieve the controllable regulation of active sites for carbon-based catalysts is reported. In particular, three distinct catalysts including metal-free N-doped carbon (NC), single Co atoms dispersed NC (Co-N-C), and Co nanoparticles-contained Co-N-C (Co/Co-N-C) are controllably realized and clearly identified by synchrotron radiation-based X-ray spectroscopy. Electrochemical measurements suggest that the Co/Co-N-C catalyst delivers optimized ORR performance due to the rich Co-Nx active sites and their synergistic effect with metallic Co nanoparticles. This work provides deep insight for rationally designing efficient ORR catalyst based on active sites engineering.

18.
Chem Commun (Camb) ; 54(35): 4481-4484, 2018 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-29658552

RESUMO

Few-layer ternary FePS3 nanosheets, prepared via chemical vapor transport synthesis and ball-milling exfoliation, exhibit excellent electrocatalytic performance for the oxygen evolution reaction in an alkaline medium. Combined with first principles calculations, our X-ray spectroscopy and HRTEM results clearly reveal that the introduction of in-plane defects in FePS3 layers after exfoliation and formation of a FePS3-FeOOH heterostructure during the OER process largely contribute to the catalytic activity enhancement.

19.
Int J Oncol ; 52(4): 1149-1164, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29532870

RESUMO

Abnormal activation of signal transducer and activator of transcription 3 (STAT3) serves a pivotal role in oral squamous cell carcinoma (OSCC) tumor cell invasion into normal tissues or distant organs. However the downstream regulatory network of STAT3 signaling remains unclear. The present study aimed to investigate the potential mechanism underlying how STAT3 triggers enhancer of zeste homolog 2 (EZH2) expression and inhibits microRNA (miR)-200a/b/429 expression in SCC25 and SCC15 cells in vitro and in vivo. Western blotting and reverse transcription-quantitative polymerase chain reaction were performed to detect expression, and numerous functional tests were conducted to explore cancer metastasis. The results indicated that when STAT3 signaling activity was attenuated by Stattic or enhanced with a STAT3 plasmid, the EZH2/miR-200 axis was markedly altered, thus resulting in modulation of the invasion and migration of OSCC cell lines. In addition, loss of function of EZH2 compromised the oncogenic role of STAT3 in both cell lines. F-actin morphology and the expression of epithelial-mesenchymal transition markers were also altered following disruption of the STAT3/EZH2/miR-200 axis. An orthotopic tumor model derived from SCC15 cells was used to confirm that targeting STAT3 or EZH2 suppressed OSCC invasion in vivo. In conclusion, the EZH2/miR-200 axis was revealed to mediate antitumor effects by targeting STAT3 signaling; these findings may provide a novel therapeutic strategy for the treatment of OSCC.


Assuntos
Carcinoma de Células Escamosas/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Neoplasias de Cabeça e Pescoço/metabolismo , MicroRNAs/biossíntese , Neoplasias Bucais/metabolismo , Fator de Transcrição STAT3/metabolismo , Animais , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Movimento Celular , Proteína Potenciadora do Homólogo 2 de Zeste/antagonistas & inibidores , Transição Epitelial-Mesenquimal , Neoplasias de Cabeça e Pescoço/patologia , Xenoenxertos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , MicroRNAs/antagonistas & inibidores , Neoplasias Bucais/patologia , Invasividade Neoplásica , Fator de Transcrição STAT3/antagonistas & inibidores , Fator de Transcrição STAT3/biossíntese , Carcinoma de Células Escamosas de Cabeça e Pescoço
20.
Adv Mater ; 30(18): e1707522, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29575370

RESUMO

Developing highly efficient catalysts for oxygen evolution reaction (OER) in neutral media is extremely crucial for microbial electrolysis cells and electrochemical CO2 reduction. Herein, a facile one-step approach is developed to synthesize a new type of well-dispersed iridium (Ir) incorporated cobalt-based hydroxide nanosheets (nominated as CoIr) for OER. The Ir species as clusters and single atoms are incorporated into the defect-rich hydroxide nanosheets through the formation of rich Co-Ir species, as revealed by systematic synchrotron radiation based X-ray spectroscopic characterizations combining with high-angle annular dark-field scanning transmission electron microscopy measurement. The optimized CoIr with 9.7 wt% Ir content displays highly efficient OER catalytic performance with an overpotential of 373 mV to achieve the current density of 10 mA cm-2 in 1.0 m phosphate buffer solution, significantly outperforming the commercial IrO2 catalysts. Further characterizations toward the catalyst after undergoing OER process indicate that unique Co oxyhydroxide and high valence Ir species with low-coordination structure are formed due to the high oxidation potentials, which authentically contributes to superior OER performance. This work not only provides a state-of-the-art OER catalyst in neutral media but also unravels the root of the excellent performance based on efficient structural identifications.

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