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1.
Eur J Pharmacol ; 973: 176585, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38636799

RESUMO

This study aimed to explore the effects and mechanism of action of stachydrine hydrochloride (Sta) against myocardial infarction (MI) through sarcoplasmic/endoplasmic reticulum stress-related injury. The targets of Sta against MI were screened using network pharmacology. C57BL/6 J mice after MI were treated with saline, Sta (6 or 12 mg kg-1) for 2 weeks, and adult mouse and neonatal rat cardiomyocytes (AMCMs and NRCMs) were incubated with Sta (10-4-10-6 M) under normoxia or hypoxia for 2 or 12 h, respectively. Echocardiography, Evans blue, and 2,3,5-triphenyltetrazolium chloride (TTC) staining were used for morphological and functional analyses. Endoplasmic reticulum stress (ERS), unfolded protein reaction (UPR), apoptosis signals, cardiomyocyte contraction, and Ca2+ flux were detected using transmission electron microscopy (TEM), western blotting, immunofluorescence, and sarcomere and Fluo-4 tracing. The ingredient-disease-pathway-target network revealed targets of Sta against MI were related to apoptosis, Ca2+ homeostasis and ERS. Both dosages of Sta improved heart function, decreased infarction size, and potentially increased the survival rate. Sta directly alleviated ERS and UPR and elicited less apoptosis in the border myocardium and hypoxic NRCMs. Furthermore, Sta upregulated sarcoplasmic reticulum Ca2+-ATPase 2a (SERCA2a) in both ischaemic hearts and hypoxic NRCMs, accompanied by restored sarcomere shortening, resting intracellular Ca2+, and Ca2+ reuptake time constants (Tau) in Sta-treated hypoxic ARCMs. However, 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ) (25 µM), a specific SERCA inhibitor, totally abolished the beneficial effect of Sta in hypoxic cardiomyocytes. Sta protects the heart from MI by upregulating SERCA2a to maintain intracellular Ca2+ homeostasis, thus alleviating ERS-induced apoptosis.


Assuntos
Apoptose , Cálcio , Estresse do Retículo Endoplasmático , Homeostase , Camundongos Endogâmicos C57BL , Miócitos Cardíacos , Prolina/análogos & derivados , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático , Animais , Estresse do Retículo Endoplasmático/efeitos dos fármacos , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Cálcio/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Homeostase/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Camundongos , Masculino , Cardiotônicos/farmacologia , Cardiotônicos/uso terapêutico , Ratos , Infarto do Miocárdio/patologia , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/prevenção & controle , Benzilisoquinolinas/farmacologia , Benzilisoquinolinas/uso terapêutico , Resposta a Proteínas não Dobradas/efeitos dos fármacos
2.
Biochem Biophys Res Commun ; 692: 149360, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38081108

RESUMO

BACKGROUND: Myocardial infarction (MI) dramatically changes the mechanical stress, which is intensified by the fibrotic remodeling. Integrins, especially the αV subunit, mediate mechanical signal and mechanoparacrine of transforming growth factor ß1 (TGF-ß1) in various organ fibrosis by activating CFs into myofibroblasts (MFBs). We investigated a possible role of integrin αV mediated mechanoparacrine of TGF-ß1 in MFBs activation for fibrous reparation in mice with MI. METHODS: Heart samples from MI, sham, or MI plus cilengitide (14 mg/kg, specific integrin αV inhibitor) treated mice, underwent functional and morphological assessments by echocardiography, and histochemistry on 7, 14 and 28 days post-surgery. The mechanical and ultrastructural changes of the fibrous scar were further evaluated by atomic mechanics microscope (AFM), immunofluorescence, second harmonic generation (SHG) imaging, polarized light and scanning electron microscope, respectively. Hydroxyproline assay was used for total collagen content, and western blot for protein expression profile examination. Fibroblast bioactivities, including cell shape, number, Smad2/3 signal and expression of extracellular matrix (ECM) related proteins, were further evaluated by microscopic observation and immunofluorescence in polyacrylamide (PA) hydrogel with adjustable stiffness, which was re-explored in fibroblast cultured on stiff matrix after silencing of integrin αV. The content of total and free TGF-ß1 was tested by enzyme-linked immunosorbent assay (ELISA) in both infarcted tissue and cell samples. RESULT: Increased stiffness with heterogeneity synchronized with integrin αV and alpha smooth muscle actin (α-SMA) positive MFBs accumulation in those less mature fibrous areas. Cilengitide abruptly reduced collagen content and disrupted collagen alignment, which also decreased TGF-ß1 bioavailability, Smad2/3 phosphorylation, and α-SMA expression in the fibrous area. Accordingly, fibroblast on stiff but not soft matrix exhibited obvious MFB phenotype, as evidenced by enlarged cell, hyperproliferation, well-developed α-SMA fibers, and elevated ECM related proteins, while silencing of integrin αV almost abolished this switch via attenuating paracrine of TGF-ß1 and nuclear translocation of Smad2/3. CONCLUSION: This study illustrated that increased tissue stiffness activates CFs into MFBs by integrin αV mediated mechanoparacrine of TGF-ß1, especially in immature scar area, which ultimately promotes fibrous scar maturation.


Assuntos
Infarto do Miocárdio , Miofibroblastos , Animais , Camundongos , Actinas/metabolismo , Cicatriz/metabolismo , Colágeno/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Fibroblastos/metabolismo , Fibrose , Integrina alfaV/metabolismo , Infarto do Miocárdio/patologia , Miofibroblastos/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta1/metabolismo
3.
Autophagy ; 19(4): 1368-1370, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36120744

RESUMO

The acidic environment within lysosomes is maintained within a narrow pH range (pH 4.5-5.0) optimal for digesting autophagic cargo macromolecules so that the resulting building block metabolites can be reused. This pH homeostasis is a consequence of proton influx produced by a V-type H+-translocating ATPase (V-ATPase) and rapid proton efflux through an unidentified "leak" pathway. By performing a candidate expression screening, we discovered that the TMEM175 gene encodes a proton-activated, proton-selective channel (LyPAP) that is required for lysosomal H+ "leak" currents. The activity of LyPAP is most active when lysosomes are hyper-acidified, and cells lacking TMEM175 exhibit lysosomal hyper-acidification and impaired proteolytic degradation, both of which can be restored by optimizing lysosomal pH using pharmacological agents. Variants of TMEM175 that are associated with susceptibility to Parkinson disease (PD) cause a reduction in TMEM175-dependent LyPAP currents and lysosomal hyper-acidification. Hence, our studies not only reveal an essential H+-dissipating pathway in lysosomes, but also provide a molecular target to regulate pH-dependent lysosomal functions and associated pathologies.


Assuntos
ATPases Vacuolares Próton-Translocadoras , ATPases Vacuolares Próton-Translocadoras/metabolismo , Autofagia/genética , Prótons , Ácidos/metabolismo , Lisossomos/metabolismo , Concentração de Íons de Hidrogênio
4.
J Psychosoc Oncol ; 40(6): 816-833, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34232115

RESUMO

OBJECTIVE: This pilot clinical trial investigated solution-focused brief therapy (SFBT) for psychological distress among adolescent and young adult (AYA) patients with cancer in China. METHODS: Fifty Chinese AYA patients diagnosed with cancer were randomized into the treatment group (SFBT) and control group (active control). Psychological distress was measured by the brief symptom inventory and hope was measured by the Herth-Hope-Index. Treatment effects were analyzed using analysis-of-covariance and between-group small-sample-size corrected Hedges' g. RESULTS: The results indicated that SFBT resulted in a significant reduction in the psychological distress and improvement in hope of AYA patients with cancer. Analyses of the 4-week posttreatment score suggest the short-term sustainability of SFBT for psychological distress among AYAs diagnosed with cancer. CONCLUSIONS AND IMPLICATIONS: This study has demonstrated that SFBT's impact is statistically significant and clinically meaningful. The inclusion of positive emotions, i.e., hope, as part of the investigation also highlighted the significance of promoting positive emotions among AYA patients with cancer.


Assuntos
Neoplasias , Angústia Psicológica , Psicoterapia Breve , Adulto Jovem , Humanos , Adolescente , Psicoterapia Breve/métodos , Projetos Piloto , Neoplasias/terapia , Neoplasias/psicologia , Povo Asiático
5.
Zhongguo Zhong Yao Za Zhi ; 46(12): 3066-3075, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34467697

RESUMO

Lycii Cortex, the dry root bark of Lycium barbarum(Solanaceae), is rich in chemical compositions with unique structures, such as organic acids, lipids, alkaloids, cyclopeptides and other components, and plays an important role in traditional Chinese medicine. It has the effect of cooling blood and removing steam, clearing lung and reducing fire. It is mainly used in the treatment of hot flashes due to Yin deficiency, hectic fever with night sweat, cough, hemoptysis and internal heat and diabetes. Modern pharmacological studies have shown that the crude extract or monomer of Lycii Cortex has a variety of pharmacological activities, such as hypoglycemic, hypotensive, hypolipidemic, antibacterial, and antiviral effects. In this paper, the chemical constituents and pharmacological effects of Cortex Lycii were reviewed in order to further clarify its effective substances, promote the development of medical undertakings, and ensure the "Healthy China" plan.


Assuntos
Lycium , China , Hipoglicemiantes , Medicina Tradicional Chinesa , Casca de Planta
6.
Zhongguo Zhong Yao Za Zhi ; 46(5): 1155-1159, 2021 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-33787110

RESUMO

Chemical constituents of water extracts of Asplenium ruprechtii were investigated. Five compounds were isolated by silica gel, Sephadex LH-20 gel column chromatographies and preparative HPLC, and their structures were identified by various spectral analyses as aspleniumside G(1), trans-p-coumaric acid(2), trans-p-coumaric acid 4-O-ß-D-glucoside(3), cis-p-coumaric acid 4-O-ß-D-glucoside(4), and(E)-ferulic acid-4-O-ß-D-glucoside(5). Among them, compound 1 is a new 9,19-cycloartane glycoside.


Assuntos
Glicosídeos , Triterpenos , Cromatografia Líquida de Alta Pressão , Glucosídeos
7.
J Sep Sci ; 44(7): 1537-1551, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33386775

RESUMO

Developing methods for the systematic and rapid identification of the chemical compositions of fresh plant tissues has long attracted the attention of phytochemists and pharmacologists. In the present study, based on highly efficient sample pretreatment and high-throughput analysis of high-performance liquid chromatography coupled with quadrupole time of flight tandem mass spectrometry data using molecular networks, a method was developed for systematically analyzing the chemical constituents of the fresh flowers of Robinia hispida L. and Robina pseudoacacia L., two congeneric ornamental species that lack prior consideration. A total of 44 glycosylated structures were characterized. And on the basis of establishing of the fragmentation pathways of 11 known flavonoid glycosides, together with the molecular networking analysis, 18 other ions of flavonoid glycosides in five classes were clustered. Moreover, 15 soyasaponins/triterpenoid glycosides were tentatively identified by comparison of their tandem mass spectrometry characteristic ions with those reported in the literature or the online Global Natural Product Social Molecular Networking database. The water extracts were separated by flash chromatography, which resulted in the discovery of one new compound, named rohispidascopolin, along with five known entities. The pharmacological targets were predicted by SwissTargetPrediction.


Assuntos
Flavonoides/análise , Flores/química , Glicosídeos/análise , Robinia/química , Cromatografia Líquida de Alta Pressão , Glicosilação , Especificidade da Espécie , Espectrometria de Massas em Tandem
8.
RSC Adv ; 11(24): 14769-14776, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35424002

RESUMO

Collecting water from fog flow has emerged as a promising strategy for the relief of water shortage problems. Herein, using a UV-induced (ultraviolet light induced) controllable diffusion method combined with technology of three-dimensional (3D) printing, we fabricate biomimetic materials incorporating beetle-like hydrophobic-hydrophilic character and cactus-like cone arrays with various structure parameters, and then systematically study their fog-harvesting performance. The UV-induced controllable diffusion method can break away from the photomask to regulate the hybrid wettability. Moreover, employing 3D printing technology can flexibly control the structure parameters to improve the water collection efficiency. It is found that the water collection rate (WCR) can be optimized by controlling the hybrid wettability of the sample surface and cone distance and using substrates with printed holes, which lead to a 109% increase of WCR.

9.
Chem Biodivers ; 17(12): e2000500, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33078897

RESUMO

We characterized a new cycloartane glycoside, herein known as aspleniumside F (1), along with five known compounds as kaempferol-3-O-[(6-O-(E)-feruloyl)-ß-D-glucopyranosyl]-(1→2)-ß-D-galacopyranoside (2), quercetin-3-O-[(6-O-(E)-feruloyl)-ß-D-glucopyranosyl]-(1→2)-ß-D-glucopyranoside (3), kaempferol-3-O-[(6-O-(E)-caffeoyl)-ß-D-glucopyranosyl]-(1→2)-ß-D-glucopyranoside (4), kaempferol-3-O-[(6-O-(E)-caffeoyl)-ß-D-glucopyranosyl]-(1→2)-ß-D-glucopyranosyl-7-O-ß-D-glucopyranoside (5), and kaempferol-3-O-[(6-O-p-coumaroyl)-ß-D-glucopyranosyl]-(1→2)-ß-D-glucopyranosyl-7-O-ß-D-glucopyranoside (6), from Asplenium ruprechtii Sa. Kurata, a folk medicine widely used to treat Thromboangiitis obliterans in China, Japan, and Korea. Based on spectroscopic, mainly 1D-, 2D-NMR and (+)-HR-ESI-MS, analyses as well as through comparisons with previous reports, its chemical structure was determined as 3ß,24,30-tri-ß-D-glucopyranosyl-23,25-dihydroxycycloartane (= (23R,24R)-3ß,24-bis-(ß-D-glucopyranosyloxy)-23,25-dihydroxy-9ß-9,19-cyclolanostan-29-yl ß-D-glucopyranoside). According to the 1 H coupling constant of anomeric protons and co-TLC of the acid hydrolysate with D-glucose, all three glycoside groups in 1 were revealed as ß-D-glucopyranosyl. Furthermore, SOD-like antioxidant activity evaluation via IC50 of 12.43, 6.78, 9.12, 6.94 and 4.85 µM revealed that compounds 2-6 had bioactivity.


Assuntos
Glicosídeos/química , Traqueófitas/química , Triterpenos/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Estrutura Molecular , Espectroscopia de Prótons por Ressonância Magnética
10.
J Phys Chem B ; 122(41): 9490-9498, 2018 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-30289255

RESUMO

The formation of a viral particle generally involves hundreds of proteins, making the assembly process intricate. Despite its intrinsic complexity, the production of a viral particle begins through the interaction between the basic assembly components. For the cowpea chlorotic mottle virus (CCMV), the first steps of the assembly process involve dimers of the capsid protein. Here, we carried out atomistic molecular dynamics simulations to investigate the initial assembly process of CCMV to get insight into the interactions at the molecular level. We found that salinity not only affects the electrostatic interactions between dimers but also changes the conformation of the positively charged N-terminal tails and can cause a serious steric hindrance for other dimers binding to the hydrophobic domains. An RNA rod was used to mimic a long segment of a viral genome and to study its interaction with dimers. We observed that the dimer with tails prefers to bind on the RNA rod with its positively charged inner side. The dimer-RNA interaction was found to be as strong as the dimer-dimer interaction, whereas the association energies between a dimer and a pentamer or a hexamer of dimers were high but strongly depended on the presence of the tails. Upon heating, the capsid experienced a shrinkage accompanied by a loss of order in the icosahedral crystal structure.


Assuntos
Bromovirus/química , Proteínas do Capsídeo/metabolismo , Proteínas do Capsídeo/química , Calefação , Simulação de Dinâmica Molecular , Ligação Proteica , Conformação Proteica , Domínios Proteicos , Multimerização Proteica , RNA Viral/química , RNA Viral/metabolismo , Eletricidade Estática
11.
Nat Commun ; 9(1): 3071, 2018 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-30082710

RESUMO

The survival of viruses partly relies on their ability to self-assemble inside host cells. Although coarse-grained simulations have identified different pathways leading to assembled virions from their components, experimental evidence is severely lacking. Here, we use time-resolved small-angle X-ray scattering to uncover the nonequilibrium self-assembly dynamics of icosahedral viral capsids packaging their full RNA genome. We reveal the formation of amorphous complexes via an en masse pathway and their relaxation into virions via a synchronous pathway. The binding energy of capsid subunits on the genome is moderate (~7kBT0, with kB the Boltzmann constant and T0 = 298 K, the room temperature), while the energy barrier separating the complexes and the virions is high (~ 20kBT0). A synthetic polyelectrolyte can lower this barrier so that filled capsids are formed in conditions where virions cannot build up. We propose a representation of the dynamics on a free energy landscape.


Assuntos
Bromovirus/fisiologia , Proteínas do Capsídeo/metabolismo , Capsídeo/metabolismo , Montagem de Vírus , Microscopia Crioeletrônica , Genoma Viral , Concentração de Íons de Hidrogênio , Polieletrólitos/química , RNA/análise , Espalhamento de Radiação , Eletricidade Estática , Termodinâmica , Vigna/virologia , Vírion/metabolismo , Raios X
12.
Angew Chem Int Ed Engl ; 57(20): 5695-5698, 2018 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-29624835

RESUMO

The first direct aziridination of triaryl-substituted alkenes was achieved by means of an electrochemical process that could extend to multisubstituted styrenes. Specifically, hexafluoroisopropanol sulfamate was used as a nucleophilic nitrogen source. Mechanistic experiments suggest that this electrochemical process proceeds by stepwise formation of two C-N bonds through reactions between cationic carbon species and the sulfamate.

13.
J Org Chem ; 83(2): 578-587, 2018 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-29260876

RESUMO

Visible-light-induced catalytic hydrophosphonodifluoromethylation of mono- and disubstituted alkenes using bromodifluoromethanephosphonate with a Hantzsch ester as the terminal reductant is reported. The combination of thiyl-radical catalysis with photoredox catalysis is important for achieving good chemoselectivity and high yields.

14.
J Phys Condens Matter ; 29(47): 474001, 2017 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-29098985

RESUMO

The dissociation of icosahedral viral capsids was investigated by a homogeneous and a heterogeneous lattice model. In thermal dissociation experiments with cowpea chlorotic mottle virus and probed by small-angle neutron scattering, we observed a slight shrinkage of viral capsids, which can be related to the strengthening of the hydrophobic interaction between subunits at increasing temperature. By considering the temperature dependence of hydrophobic interaction in the homogeneous lattice model, we were able to give a better estimate of the effective charge. In the heterogeneous lattice model, two sets of lattice sites represented different capsid subunits with asymmetric interaction strengths. In that case, the dissociation of capsids was found to shift from a sharp one-step transition to a gradual two-step transition by weakening the hydrophobic interaction between AB and CC subunits. We anticipate that such lattice models will shed further light on the statistical mechanics underlying virus assembly and disassembly.

15.
Nanomaterials (Basel) ; 7(11)2017 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-29117136

RESUMO

Cholesteric liquid crystals (CLCs) exhibit selective Bragg reflections of circularly polarized (CP) light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC) structures. To endow these optical patterns with tunability, we fabricated spherical CLC Bragg reflectors in the shape of microshells by glass-capillary microfluidics. Water-soluble magnetofluid with Fe3O4 nanoparticles incorporated in the inner aqueous core of CLC shells is responsible for the non-invasive transportable capability. With the aid of an external magnetic field, the reflection interactions between neighboring microshells and microdroplets were identified by varying the mutual distance in a group of magnetically transportable and unmovable spherical CLC structures. The temperature-dependent optical reflection patterns were investigated in close-packed hexagonal arrangements of seven CLC microdroplets and microshells with inverse helicity handedness. Moreover, we demonstrated that the magnetic field-assisted assembly of microshells array into geometric figures of uppercase English letters "L" and "C" was successfully achieved. We hope that these findings can provide good application prospects for security pattern designs.

16.
J Org Chem ; 81(20): 9992-10001, 2016 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-27661095

RESUMO

We report the first example of difluoroalkylation/C-H annulation cascade reactions of cyclopropyl olefins induced by visible-light photoredox catalysis regioselectively affording partially hydrogenated naphthalenes and quinolines with a variety of difluorinated side chains. The alkylation reagent could be extended to monofluoro and trifluoro reagents, nitrile and malonate. The regioselectivity was investigated by means of density functional theory calculations.

17.
ACS Appl Mater Interfaces ; 7(3): 1892-8, 2015 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-25548958

RESUMO

A new 3D TNW-AuNP plasmonic electrode consists of antireflective (AR) TiO2 nanowires (TNWs) (∼600 nm thickness) serving as light-harvesting antennae coupling with Au nanoparticles (NPs). A huge red-shift of 55 nm is observed in surface plasmon spectra for the Au (11 nm) plasmonic electrode that has 11 nm size Au NPs, whereby (111) lattice planes have a specific bonding with the TiO2 (101) planes. Remarkable red-shift is mainly attributed to the localized electric field improvement resulting from the plasmonic coupling effect between the Au NPs and the Au-TiO2 hybrids. After TiCl4 treatment, this favorable Au (11 nm) nanostructure takes advantage of harvesting photons to increase the conversion efficiency of dye-sensitized solar cells (DSSCs) from 6.25% to 9.73%.

18.
ACS Appl Mater Interfaces ; 6(23): 20994-9, 2014 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-25402346

RESUMO

Great demand toward flexible optoelectronic devices finds metal nanowires (NWs) the most promising flexible transparent conducting material with superior mechanical properties. However, ultrathin metal nanowires suffer from relatively poor thermal stability and sheet conductance, attributed to the poor adhesivity of the ohmic contact between nanowires. Thermal heating and annealing at 200 °C increase the conductivity of the metal network, but prolonged annealing accelerates the breakage of NWs near the NW junction and the formation of Ag droplets. In this study, the thermal stability of silver NW (AgNW) films is investigated through the in situ measurements of sheet resistance and terahertz (THz) conductivity. With the improved ohmic contact at the NW junctions by heating, a characteristic transition from the subpercolative to percolative network is observed by in situ THz spectroscopy. It is found that stamp-transferred graphene incorporated with a near-percolative AgNW network can dramatically enhance the thermal stability of the graphene-AgNW (GAgNW) hybrid film. In both in situ measurements, little variation of physical parameters in GAgNW film is observed for up to 3 h of annealing. The presented results offer the potential of graphene-incorporated metal nanowire film as a highly conductive electrode that also has high thermal stability and excellent transparency for next-generation electronics and optoelectronics on flexible substrates.

19.
Nanotechnology ; 25(23): 235602, 2014 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-24848377

RESUMO

A 3-dimensional chain-network anatase/TiO2 (B) was obtained via the basic hydrothermal treatment of a sandwich Ti/TiO2/Ti film on a glass substrate that was prepared from 16 nm anatase TiO2 nanoparticles. The Ti film was converted to the TiO2 (B) phase in a Teflon vessel containing a 10 M NaOH aqueous solution that was encapsulated in a stainless-steel autoclave and heated at 130 °C for 2 h. The TiO2 (B) then served as a binder layer that enabled the formation of pearl-necklace chains made of anatase TiO2 nanoparticles, and these chain-like structures thoroughly interpenetrated into the textured layer. Decomposition tests using methylene blue indicated that the chain-network anatase/TiO2 (B) mixed-phase film had a photocatalytic half-life that was 0.84 and 0.69 times shorter than those of as-prepared anatase TiO2 and P25, respectively. In addition, the intensity of the room temperature photoluminescence spectra of anatase TiO2 was 2.55-fold higher than that of the chain-network anatase/TiO2 (B). We thus conclude that the remarkable photocatalytic activity of the chain-network anatase/TiO2 (B) is attributed to the chain-network structural characteristics and a synergistic effect of the matching band gap potentials, which increases the transfer of photogenerated electrons and reduces electron-hole recombination.

20.
ACS Nano ; 6(8): 6633-9, 2012 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-22757633

RESUMO

Dual functionalities of antireflective and electrochromic properties-based anatase TiO(2) nanowire devices with a high-porosity cross-linked geometry directly grown onto transparent conductive glass was achieved for the first time through a simple one-step hydrothermal process under mild alkali conditions. Devices fashioned from these TiO(2) nanowires were found to display enhanced optical transparency in the visible range, better color contrast, and faster color-switching time in comparison to devices made from nanoparticles. These improvements can be attributed to the low refractive index and high porosity of the TiO(2) nanowires and their larger accessible surface area for Li(+) intercalation and deintercalation, leading to enhanced capabilities for transparent electrochromic smart windows.


Assuntos
Cristalização/métodos , Microeletrodos , Nanotubos/química , Nanotubos/ultraestrutura , Refratometria/instrumentação , Titânio/química , Água/química , Cor , Campos Eletromagnéticos , Desenho de Equipamento , Análise de Falha de Equipamento , Temperatura Alta , Teste de Materiais , Tamanho da Partícula
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