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1.
Small ; : e2402427, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38751309

RESUMO

Halogenated methane serves as a universal platform molecule for building high-value chemicals. Utilizing sodium chloride solution for photocatalytic methane chlorination presents an environmentally friendly method for methane conversion. However, competing reactions in gas-solid-liquid systems leads to low efficiency and selectivity in photocatalytic methane chlorination. Here, an in situ method is employed to fabricate a hydrophobic layer of TaOx species on the surface of NaTaO3. Through in-situ XPS and XANES spectra analysis, it is determined that TaOx is a coordination unsaturated species. The TaOx species transforms the surface properties from the inherent hydrophilicity of NaTaO3 to the hydrophobicity of TaOx/NaTaO3, which enhances the accessibility of CH4 for adsorption and activation, and thus promotes the methane chlorination reaction within the gas-liquid-solid three-phase system. The optimized TaOx/NaTaO3 photocatalyst has a good durability for multiple cycles of methane chlorination reactions, yielding CH3Cl at a rate of 233 µmol g-1 h-1 with a selectivity of 83%. In contrast, pure NaTaO3 exhibits almost no activity toward CH3Cl formation, instead catalyzing the over-oxidation of CH4 into CO2. Notably, the activity of the optimized TaOx/NaTaO3 photocatalyst surpasses that of reported noble metal photocatalysts. This research offers an effective strategy for enhancing the selectivity of photocatalytic methane chlorination using inorganic chlorine ions.

2.
J Am Chem Soc ; 145(10): 5769-5777, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36863033

RESUMO

A series of novel surface Ru-H bipyridine complexes-grafted TiO2 nanohybrids were for the first time prepared by a combined procedure of surface organometallic chemistry with post-synthetic ligand exchange for photocatalytic conversion of CO2 to CH4 with H2 as electron and proton donors under visible light irradiation. The selectivity toward CH4 increased to 93.4% by the ligand exchange of 4,4'-dimethyl-2,2'-bipyridine (4,4'-bpy) with the surface cyclopentadienyl (Cp)-RuH complex and the CO2 methanation activity was enhanced by 4.4-fold. An impressive rate of 241.2 µL·g-1·h-1 for CH4 production was achieved over the optimal photocatalyst. The femtosecond transient IR absorption results demonstrated that the hot electrons were fast injected in 0.9 ps from the photoexcited surface 4,4'-bpy-RuH complex into the conduction band of TiO2 nanoparticles to form a charge-separated state with an average lifetime of ca. 50.0 ns responsible for the CO2 methanation. The spectral characterizations indicated clearly that the formation of CO2•- radicals by single electron reduction of CO2 molecules adsorbed on surface oxygen vacancies of TiO2 nanoparticles was the most critical step for the methanation. Such radical intermediates were inserted into the explored Ru-H bond to generate Ru-OOCH species and finally CH4 and H2O in the presence of H2.

3.
Small ; 19(14): e2207581, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36651007

RESUMO

Overall photocatalytic conversion of CO2 and pure H2 O driven by solar irradiation into methanol provides a sustainable approach for extraterrestrial synthesis. However, few photocatalysts exhibit efficient production of CH3 OH. Here, BiOBr nanosheets supporting atomic Cu catalysts for CO2 reduction are reported. The investigation of charge dynamics demonstrates a strong built-in electric field established by isolated Cu sites as electron traps to facilitate charge transfer and stabilize charge carriers. As result, the catalysts exhibit a substantially high catalytic performance with methanol productivity of 627.66 µmol gcatal -1 h-1 and selectivity of ≈90% with an apparent quantum efficiency of 12.23%. Mechanism studies reveal that the high selectivity of methanol can be ascribed to energy-favorable hydrogenation of *CO intermediate giving rise to *CHO. The unfavorable adsorption on Cu1 @BiOBr prevents methanol from being oxidized by photogenerated holes. This work highlights the great potential of single-atom photocatalysts in chemical transformation and energy storage reactions.

4.
Angew Chem Int Ed Engl ; 62(36): e202309026, 2023 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-37460792

RESUMO

The keto-switched photocatalysis of covalent organic frameworks (COFs) for efficient H2 evolution was reported for the first time by engineering, at a molecular level, the local structure and component of the skeletal building blocks. A series of imine-linked BT-COFs were synthesized by the Schiff-base reaction of 1, 3, 5-benzenetrialdehyde with diamines to demonstrate the structural reconstruction of enol to keto configurations by alkaline catalysis. The keto groups of the skeletal building blocks served as active injectors, where hot π-electrons were provided to Pt nanoparticles (NPs) across a polyvinylpyrrolidone (PVP) insulting layer. The characterization results, together with density functional theory calculations, indicated clearly that the formation of keto-injectors not only made the conduction band level more negative, but also led to an inhomogeneous charge distribution in the donor-acceptor molecular building blocks to form a strong intramolecular built-in electric field. As a result, visible-light photocatalysis of TP-COFs-1 with one keto group in the skeletal building blocks was successfully enabled and achieved an impressive H2 evolution rate as high as 0.96 mmol g-1 h-1 . Also, the photocatalytic H2 evolution rates of the reconstructed BT-COFs-2 and -3 with two and three keto-injectors were significantly enhanced by alkaline post-treatment.

5.
J Gene Med ; 23(3): e3306, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33450091

RESUMO

BACKGROUND: Long non-coding RNA MCM3AP antisense RNA 1 (lncRNA MCM3AP-AS1) has a regulatory role in the development of diverse malignancies, whereas its role and mechanism in colorectal cancer (CRC) is not yet clear. METHODS: The relative expression of MCM3AP-AS1, miR-19a-3p and forkhead box F2 (FOXF2) mRNA in 53 cases of CRC and its adjacent normal tissues, human normal colonic mucosal cells (FHC cells) and CRC cell lines was examined by a quantitative real-time polymerase chain reaction, and the changes of cell multiplication and migration were examined by the cell counting kit-8 method, EdU test, and scratch-healing test, respectively. Bioinformatics, dual-luciferase reporter gene assay and a RNA immunoprecipitation experiment were adopted to predict and verify the relationship between MCM3AP-AS1 and miR-19a-3p; bioinformatics and dual-luciferase reporter gene assay were adopted to predict and verify the relationship between miR-19a-3p and FOXF2. Western blotting was executed to examine the effects of MCM3AP-AS1 overexpression or knockdown on FOXF2 protein expression. RESULTS: MCM3AP-AS1 expression was down-modulated in CRC, and its dysregulation was linked to unfavorable pathological characteristics. MCM3AP-AS1 significantly impeded the multiplication and migration of CRC cells. MCM3AP-AS1 was recognized as a molecular sponge to suppress miR-19a-3p expression, and FOXF2 was a target gene of miR-19a-3p. MCM3AP-AS1 positively modulated FOXF2 expression, and its biological effect was dependent the on miR-19a-3p/FOXF2 axis. CONCLUSIONS: MCM3AP-AS1 can inhibit CRC promoting by modulating the miR-19a-3p/FOXF2 axis.


Assuntos
Acetiltransferases/metabolismo , Neoplasias Colorretais/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , MicroRNAs/metabolismo , RNA Antissenso/metabolismo , RNA Longo não Codificante/metabolismo , Acetiltransferases/genética , Animais , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Neoplasias Colorretais/genética , Progressão da Doença , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Camundongos , Camundongos Nus , Metástase Neoplásica , RNA Antissenso/genética , RNA Longo não Codificante/genética , Transdução de Sinais
6.
Respir Res ; 22(1): 281, 2021 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-34717626

RESUMO

BACKGROUND: This study examined whether BI113823, a novel selective kinin B1 receptor antagonist can reverse established pulmonary arterial hypertension (PAH), prevent right heart failure and death, which is critical for clinical translation. METHODS: Left pneumonectomized male Wistar rats were injected with monocrotaline to induce PAH. Three weeks later, when PAH was well established, the rats received daily treatment of BI113823 or vehicle for 3 weeks. RESULTS: Treatment with BI113823 from day 21 to day 42 after monocrotaline injection reversed established PAH as shown by normalized values of mean pulmonary arterial pressure (mPAP). BI113823 therapy reversed pulmonary vascular remodeling, pulmonary arterial neointimal formation, and heart and lung fibrosis, reduced right ventricular pressure, right heart hypertrophy, improved cardiac output, and prevented right heart failure and death. Treatment with BI113823 reduced TNF-α and IL-1ß, and macrophages recruitment in bronchoalveolar lavage, reduced CD-68 positive macrophages and expression of proliferating cell nuclear antigen (PCNA) in the perivascular areas, and reduced expression of iNOS, B1 receptors, matrix metalloproteinase (MMP)-2 and MMP-9 proteins, and the phosphorylation of ERK1/2 and AKT in lung. Treatment with BI113823 reduced mRNA expression of ANP, BNP, ßMHC, CGTF, collange-I and IV in right heart, compared to vehicle treated controls. In human monocytes cultures, BI113823 reduced LPS-induced TNF-α production, MMP-2 and MMP-9 expression, and reduced TNF-α-induced monocyte migration. CONCLUSIONS: We conclude that BI113823 reverses preexisting severe experimental pulmonary hypertension via inhibition of macrophage infiltration, cytokine production, as well as down regulation of matrix metalloproteinase proteins.


Assuntos
Cininas/antagonistas & inibidores , Neointima/patologia , Hipertensão Arterial Pulmonar/patologia , Artéria Pulmonar/patologia , Túnica Íntima/patologia , Remodelação Vascular/efeitos dos fármacos , Animais , Modelos Animais de Doenças , Humanos , Masculino , Hipertensão Arterial Pulmonar/tratamento farmacológico , Hipertensão Arterial Pulmonar/metabolismo , Artéria Pulmonar/efeitos dos fármacos , Ratos , Ratos Wistar , Túnica Íntima/efeitos dos fármacos
7.
Inorg Chem ; 60(19): 14854-14865, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34520176

RESUMO

The construction of a phase junction photocatalyst can significantly enhance the photocatalytic performance with high selectivity for CO2 reduction. In this study, an S-scheme junction Cd0.5Zn0.5S/CoWO4 semiconductor with the coupling of a twin crystal Cd0.5Zn0.5S homojunction and CoWO4 was designed through a hydrothermal method, which could convert CO2 to CO with high efficiency under visible-light illumination. Cd0.5Zn0.5S-10%CoWO4 exhibited the optimal performance and its CO yield and selectivity were up to 318.68 µmol·g-1 and 95.90%, respectively, which were 4.54 and 1.62 times higher than that of twin crystal Cd0.5Zn0.5S. Moreover, the Cd0.5Zn0.5S homojunction with a zinc-blende and wurtzite phase and the S-scheme phase junction of Cd0.5Zn0.5S/CoWO4 enhanced the property of CO2 adsorption and accelerated the detachment of photogenerated carriers. The combination of photogenerated holes in Cd0.5Zn0.5S and the electrons of CoWO4 can retain the reduction sites to improve photocatalytic performance. This study provides a neoteric concept and reference for the construction of the S-scheme phase junction.

8.
Phys Chem Chem Phys ; 23(1): 186-195, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33319875

RESUMO

In this work, TiO2 was modified by doping the electron-deficient B element, and then the gas-sensing response of B-TiO2 to H2 under UV irradiation at room temperature in a N2 atmosphere and the oxidation of H2 over B-TiO2 under corresponding conditions were tested. It was found that H2 would accept an electron when adsorbed on the TiO2 surface, while H2 would donate an electron when adsorbed on the B-TiO2 surface. Correspondingly, H2 could not be oxidized over TiO2, but could be oxidized over B-TiO2. This indicated that the oxidation of H2 was dependent on the electron-transfer behavior between H2 and the surface of TiO2 or B-TiO2. Based on the relevant characterization results, it was proposed that H2 could accept an electron from TiO2 due to the higher Fermi level of TiO2, while H2 could donate an electron to B-TiO2 due to the lower Fermi level of B-TiO2 induced by doping B. This indicated that the electron-transfer behavior between H2 and TiO2 could be changed by adjusting the Fermi level of TiO2, while the electron-transfer behavior would further affect the photocatalytic activity of oxidizing H2. This result shows that the doable H2 photocatalytic oxidation in thermodynamics can be controlled by a kinetics factor (H2 losing-an-electron behavior). This work can be applied to provide an understanding of the photocatalytic oxidation behavior of other reactants over semiconductor materials.

9.
Exp Mol Pathol ; 115: 104428, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32205097

RESUMO

PURPOSES: Recently, Methylcrotonoyl-CoA carboxylase 2 (MCCC2) is reported to be involved in tumor formation and progression. However, MCCC2 has nerve been reported in colorectal cancer. In this study, we aimed to investigate the role of MCCC2 in colorectal cancer. METHODS: 118 colorectal cancer and matched adjacent normal tissues were enrolled in this study. The expression level of MCCC2 was measured by quantificational real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). The clinical significance of MCCC2 and its influence on cell proliferation was further analyzed. RESULTS: Results shown that the mRNA levels of MCCC2 in colorectal cancer tissues were significantly increased compared with those in normal tissues (P < .0001). MCCC2 high-expression was observed in 56.8% colorectal cancer tissues, which was significantly higher than those in normal controls (9.3%, P < .0001). MCCC2 high-expression correlated with tumor size, T stage, lymph node metastasis, distant metastasis, clinical stage and differentiation in colorectal cancer (P < .05). Moreover, MCCC2 high-expression predicted poorer prognosis and could be as an independent prognostic factor. In addition, MCCC2 knockdown significantly inhibited cell proliferation compared with these controls, while MCCC2 overexpression could reverse the effect. CONCLUSION: These data indicate MCCC2 overexpression promotes cell proliferation and predicts poorer prognosis in colorectal cancer.


Assuntos
Carbono-Carbono Ligases/metabolismo , Neoplasias Colorretais/enzimologia , Neoplasias Colorretais/patologia , Carbono-Carbono Ligases/genética , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias Colorretais/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Prognóstico , Regulação para Cima
10.
Sensors (Basel) ; 20(9)2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32365747

RESUMO

Convolution neural network (CNN)-based detectors have shown great performance on ship detections of synthetic aperture radar (SAR) images. However, the performance of current models has not been satisfactory enough for detecting multiscale ships and small-size ones in front of complex backgrounds. To address the problem, we propose a novel SAR ship detector based on CNN, which consist of three subnetworks: the Fusion Feature Extractor Network (FFEN), Region Proposal Network (RPN), and Refine Detection Network (RDN). Instead of using a single feature map, we fuse feature maps in bottom-up and top-down ways and generate proposals from each fused feature map in FFEN. Furthermore, we further merge features generated by the region-of-interest (RoI) pooling layer in RDN. Based on the feature representation strategy, the CNN framework constructed can significantly enhance the location and semantics information for the multiscale ships, in particular for the small ships. On the other hand, the residual block is introduced to increase the network depth, through which the detection precision could be further improved. The public SAR ship dataset (SSDD) and China Gaofen-3 satellite SAR image are used to validate the proposed method. Our method shows excellent performance for detecting the multiscale and small-size ships with respect to some competitive models and exhibits high potential in practical application.

11.
J Cell Biochem ; 120(10): 18446-18456, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31211466

RESUMO

This study is performed to elucidate whether long-chain noncoding RNA ANRIL has an effect on diabetes, and further explore the mechanism of ANRIL in diabetes. The rat model of diabetes was established via intraperitoneal injection of streptozotocin. The modeled rats were grouped into normal, diabetes, siRNA-NC, and ANRIL siRNA groups. Besides, the expression of ANRIL, cardiac function, inflammatory factor levels, cardiomyocyte apoptosis, and levels of oxidative stress index were all determined. Upregulated ANRIL was found in myocardial tissue of diabetic rats. Downregulated ANRIL improved cardiac function index and the expression of inflammatory factors, improved the pathological state of myocardial tissue and myocardial remodeling, decreased myocardial collagen deposition area and cardiomyocyte apoptosis and reduced the oxidative level of myocardial tissue in diabetic rats. This present study suggests that upregulated ANRIL is found in myocardial tissue of diabetic rats. Additionally, silencing of ANRIL reduces myocardial injury in diabetes by inhibiting myocardial oxidative stress.


Assuntos
Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/patologia , Miocárdio/metabolismo , Miocárdio/patologia , RNA Longo não Codificante/metabolismo , Animais , Apoptose/genética , Apoptose/fisiologia , Western Blotting , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Ecocardiografia , Ensaio de Imunoadsorção Enzimática , Insuficiência Cardíaca/genética , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Masculino , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologia , RNA Longo não Codificante/genética , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio
12.
Inorg Chem ; 55(7): 3680-4, 2016 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-27040717

RESUMO

Host-guest encapsulation of electron-rich naphthalene molecules into a weakly emissive porous metal-organic framework based on π-electron-deficient (π-acidic) naphthalene diimide tectons leads to orange-emissive crystals, which can be used to sense strongly basic organic amines in a fast response, high photostability, and tunable sensitivity. Moreover, such host-guest inclusion crystals are also a good photochromic probe for the detection of weakly basic N-methyl-2-pyrrolidone and N,N-dimethylformamide molecules.

13.
Sensors (Basel) ; 16(8)2016 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-27509502

RESUMO

An anatase TiO2 film sensor was prepared by a facile in-situ method on the interdigitated Au electrode deposited on the alumina substrate. The structure, morphology and the optical properties of the in-situ TiO2 film sensor were characterized by X-ray diffraction, Scanning Electron Microscopy, and UV-vis diffuse reflectance spectra. The photo-assisted gas sensitivities of the prepared film towards H2 gas were evaluated at room temperature in N2 and synthetic air atmospheres. As compared to TiO2 film sensor prepared by drop-coating method, this in-situ TiO2 film sensor exhibited a more compact structure composed of uniform TiO2 microspheres as well as a better gas sensitivity towards H2 under UV irradiation, especially in synthetic air. The photo-electrochemical measurements suggest that these improvements may be associated with the efficient charge transfer in the TiO2 interface induced by the TiO2 microsphere structure. This study might offer a feasible approach to develop photo-assisted gas sensors at ambient temperature.

14.
J Colloid Interface Sci ; 674: 158-167, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38925061

RESUMO

Constructing strong interfacial electric fields to enhance the surface charge transport kinetics is an effective strategy for promoting CO2 conversion. Herein, we present the fabrication of CdS-Bi2MoO6 Z-scheme heterojunctions with a robust internal electric field (IEF) using an in situ growth technique, establishing chemical bonding between the components. The IEF at the interface can offer an impetus for the segregation and transportation of photogenerated carriers, while the Cd-O chemical bonding mode acts as a rapid conduit for these carriers, thereby reducing the charge transfer distance. As a result, the Z-scheme charge transfer is accelerated due to the synergistic influence of these two factors. Therefore, the optimized CdS/Bi2MoO6 Z-scheme heterojunction possesses significantly enhanced dynamic carrier mobility, thus promoting the conversion of CO2 to CO without the need for additional co-catalysts or sacrificial agents. This optimization yields a remarkable CO selectivity of up to 97%. Meanwhile, the expedited Z-scheme charge transfer mechanism is validated through X-ray photoelectron spectroscopy, Kelvin probe force microscopy, and in situ diffuse reflectance infrared Fourier transform spectroscopy.

15.
Adv Mater ; 36(5): e2303845, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37638643

RESUMO

Piezo-photocatalysis is a frontier technology for converting mechanical and solar energies into crucial chemical substances and has emerged as a promising and sustainable strategy for N2 fixation. Here, for the first time, defects and piezoelectric field are synergized to achieve unprecedented piezo-photocatalytic nitrogen reduction reaction (NRR) activity and their collaborative catalytic mechanism is unraveled over BaTiO3 with tunable oxygen vacancies (OVs). The introduced OVs change the local dipole state to strengthen the piezoelectric polarization of BaTiO3 , resulting in a more efficient separation of photogenerated carrier. Ti3+ sites adjacent to OVs promote N2 chemisorption and activation through d-π back-donation with the help of the unpaired d-orbital electron. Furthermore, a piezoelectric polarization field could modulate the electronic structure of Ti3+ to facilitate the activation and dissociation of N2 , thereby substantially reducing the reaction barrier of the rate-limiting step. Benefitting from the synergistic reinforcement mechanism and optimized surface dynamics processes, an exceptional piezo-photocatalytic NH3 evolution rate of 106.7 µmol g-1  h-1 is delivered by BaTiO3 with moderate OVs, far surpassing that of previously reported piezocatalysts/piezo-photocatalysts. New perspectives are provided here for the rational design of an efficient piezo-photocatalytic system for the NRR.

16.
ACS Nano ; 18(15): 10582-10595, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38564712

RESUMO

CO2 conversion with pure H2O into CH3OH and O2 driven by solar energy can supply fuels and life-essential substances for extraterrestrial exploration. However, the effective production of CH3OH is significantly challenging. Here we report an organozinc complex/MoS2 heterostructure linked by well-defined zinc-sulfur covalent bonds derived by the structural deformation and intensive coupling of dx2 - y2(Zn)-p(S) orbitals at the interface, resulting in distinctive charge transfer behaviors and excellent redox capabilities as revealed by experimental characterizations and first-principle calculations. The synthesis strategy is further generalized to more organometallic compounds, achieving various heterostructures for CO2 photoreduction. The optimal catalyst delivers a promising CH3OH yield of 2.57 mmol gcat-1 h-1 and selectivity of more than 99.5%. The reverse water gas shift mechanism is identified for methanol formation. Meanwhile, energy-unfavorable adsorption of methanol on MoS2, where the photogenerated holes accumulate, ensures the selective oxidation of water over methanol.

17.
Nat Commun ; 14(1): 6168, 2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37794001

RESUMO

The active center for the adsorption and activation of carbon dioxide plays a vital role in the conversion and product selectivity of photocatalytic CO2 reduction. Here, we find multiple metal sulfides CuInSnS4 octahedral nanocrystal with exposed (1 1 1) plane for the selectively photocatalytic CO2 reduction to methane. Still, the product is switched to carbon monoxide on the corresponding individual metal sulfides In2S3, SnS2, and Cu2S. Unlike the common metal or defects as active sites, the non-metal sulfur atom in CuInSnS4 is revealed to be the adsorption center for responding to the selectivity of CH4 products. The carbon atom of CO2 adsorbed on the electron-poor sulfur atom of CuInSnS4 is favorable for stabilizing the intermediates and thus promotes the conversion of CO2 to CH4. Both the activity and selectivity of CH4 products over the pristine CuInSnS4 nanocrystal can be further improved by the modification of with various co-catalysts to enhance the separation of the photogenerated charge carrier. This work provides a non-metal active site to determine the conversion and selectivity of photocatalytic CO2 reduction.

18.
Acta Pharm Sin B ; 2023 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-37360012

RESUMO

Via an insufficient coat protein complex I (COPI) retrieval signal, the majority of SARS-CoV-2 spike (S) is resident in host early secretory organelles and a tiny amount is leaked out in cell surface. Only surface-exposed S can be recognized by B cell receptor (BCR) or anti-S therapeutic monoclonal antibodies (mAbs) that is the trigger step for B cell activation after S mRNA vaccination or infected cell clearance by S mAbs. Now, a drug strategy to promote S host surface exposure is absent. Here, we first combined structural and biochemical analysis to characterize S COPI sorting signals. A potent S COPI sorting inhibitor was then invented, evidently capable of promoting S surface exposure and facilitating infected cell clearance by S antibody-dependent cellular cytotoxicity (ADCC). Importantly, with the inhibitor as a probe, we revealed Omicron BA.1 S is less cell surface exposed than prototypes because of a constellation of S folding mutations, possibly corresponding to its ER chaperone association. Our findings not only suggest COPI is a druggable target against COVID-19, but also highlight SARS-CoV-2 evolution mechanism driven by S folding and trafficking mutations.

19.
Chemphyschem ; 13(6): 1542-50, 2012 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-22407673

RESUMO

The electronic structure and photoactivation process in N-doped TiO(2) is investigated. Diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and electron paramagnetic resonance (EPR) are employed to monitor the change of optical absorption ability and the formation of N species and defects in the heat- and photoinduced N-doped TiO(2) catalyst. Under thermal treatment below 573 K in vacuum, no nitrogen dopant is removed from the doped samples but oxygen vacancies and Ti(3+) states are formed to enhance the optical absorption in the visible-light region, especially at wavelengths above 500 nm with increasing temperature. In the photoactivation processes of N-doped TiO(2), the DRS absorption and PL emission in the visible spectral region of 450-700 nm increase with prolonged irradiation time. The EPR results reveal that paramagnetic nitrogen species (N(s)·, oxygen vacancies with one electron (V(o)·), and Ti(3+) ions are produced with light irradiation and the intensity of N(s)· species is dependent on the excitation light wavelength and power. The combined characterization results confirm that the energy level of doped N species is localized above the valence band of TiO(2) corresponding to the main absorption band at 410 nm of N-doped TiO(2), but oxygen vacancies and Ti(3+) states as defects contribute to the visible-light absorption above 500 nm in the overall absorption of the doped samples. Thus, a detailed picture of the electronic structure of N-doped TiO(2) is proposed and discussed. On the other hand, the transfer of charge carriers between nitrogen species and defects is reversible on the catalyst surface. The presence of oxygen-vacancy-related defects leads to quenching of paramagnetic N(s)· species but they stabilize the active nitrogen species N(s)(-).

20.
ACS Appl Mater Interfaces ; 14(19): 22531-22543, 2022 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-35504733

RESUMO

Photocatalytic conversions of C1 molecules under mild conditions have been widely researched in many fields. Adsorption of reactants at a catalyst surface is an indispensable process for C1 conversion and thus it might play a key role in reaction behavior. Herein, for a ZnO sample without photocatalytic activity for CO + H2 reduction, CuO is introduced into ZnO to regulate the adsorption behavior of CO on the CuO-ZnO surface and then to drive the reduction of CO by H2 under UV irradiation. The results of gas sensitivity tests and various in situ characterization methods are as expected. Specifically, surface zinc vacancies and Cu2+ sites at the interface of ZnO and CuO cooperate to construct a special electron-transfer channel (Zn-O-Cu-O) for CO adsorption [CO (ads)]. A new linear adsorption mode of CO at Cu2+ sites occurs, and this successfully changes the electron-transfer behavior of CO (ads) from donating electrons (to ZnO) to accepting electrons (from CuO-ZnO) via electron-transfer channels and d-electrons of Cu2+ matching. Then, CO molecules are reduced by H2 under UV irradiation. The strategy here provides an insight into the design of highly effective catalysts as well as an in-depth understanding of the mechanism of C1 photocatalytic conversion.

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