Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nanotechnology ; 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32045900

RESUMO

Here, we successfully fabricated GO wrapped Ti/Co3O4NWs by electrophoretic deposition (EPD) based on the good dispersibility of GO in aqueous solution. Interestingly, GO can adhere to the surface of Co3O4NWs via ultrathin gossamer-like sheet, and the coverage and wrapping of GO on the surface of Co3O4NWs can be controlled by tuning the electrochemical deposition time and voltage. Our results also demonstrate that GO wrapped Co3O4 NWs had superior photoelectrochemical (PEC) activity for decolorization of dye (reactive brilliant blue KN-R) wastewater, mainly because the introduction of GO can tune oxygen evolution behavior, transportation of reactant and induced carriers, electrochemical active areas, and light-harvesting capability of Co3O4 NWs. Therefore,we anticipate that GO wrapped Ti/Co3O4 NWs could be considered as a promising photoanode for the treatment of organic pollutants in wastewater.

2.
Sensors (Basel) ; 19(23)2019 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-31771138

RESUMO

In Airborne Light Detection and Ranging (LiDAR) data acquisition practice, discrepancies exist between adjacent strips even though careful system calibrations have been performed. A strip adjustment method using planar features acquired by the Minimum Hausdorff Distance (MHD) is proposed to eliminate these discrepancies. First, semi-suppressed fuzzy C-means and restricted region growing algorithms are used to extract buildings. Second, a binary image is generated from the minimum bounding rectangle that covers overlapping regions. Then, connected components labeling algorithm is applied to process the binary image to extract individual buildings. After that, building matching is performed based on MHD. Third, a coarse-to-fine approach is used to segment building roof planes. Then, plane matching is conducted under the constraints of MHD and normal vectors similarity. The last step is the calculation of the parameters based on Euclidean distance minimization between matched planes. Two different types of datasets, one of which was acquired by a dual-channel LiDAR system Trimble AX80, were selected to verify the proposed method. Experimental results show that the corresponding planar features that meet adjustment requirements can be successfully detected without any manual operations or auxiliary data or transformation of raw data, while the discrepancies between strips can be effectively eliminated. Although adjustment results of the proposed method slightly outperform the comparison alternative, the proposed method also has the advantage of processing the adjustment in a more automatic manner than the comparison method.

3.
Carbohydr Polym ; 197: 326-336, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30007620

RESUMO

Hyaluronan (HA) possesses manifold mechanical and signaling properties in the body. Most of these activities are largely regulated by its molecular weight, which often triggers opposing functions. However the molecular basis for such function distinction between HA size categories remains unclear. Using a combination of biophysical techniques, we measured the physical forces between HA ligand and its specific receptor CD44 in both normal and lateral directions, at different HA molecular weights and bound states. It was found that the impact of HA multivalency is more than just the sum of separate monovalent bindings. The HA-CD44 specific interaction enhances with HA molecular weight and the maximum binding occurs at ∼1000 kD, possibly due to the balance between multivalent HA zipping effect and conformational entropy. High friction patches, probably from CD44 protein clustering, was observed in friction force microscopy (FFM) upon HA shearing, which is also dependent on HA molecular weight. These results could help to understand the biophysical mechanism of HA in regulating CD44-induced physiological activities and thus facilitate the new design of HA-based material in fine tuning the receptor responses.


Assuntos
Receptores de Hialuronatos/química , Ácido Hialurônico/química , Animais , Sobrevivência Celular/efeitos dos fármacos , Células HCT116 , Células HeLa , Humanos , Ácido Hialurônico/farmacologia , Camundongos , Microscopia de Força Atômica , Peso Molecular , Células NIH 3T3 , Estresse Mecânico
4.
J Healthc Eng ; 2018: 7273451, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29666671

RESUMO

Obstetric electronic medical records (EMRs) contain massive amounts of medical data and health information. The information extraction and diagnosis assistants of obstetric EMRs are of great significance in improving the fertility level of the population. The admitting diagnosis in the first course record of the EMR is reasoned from various sources, such as chief complaints, auxiliary examinations, and physical examinations. This paper treats the diagnosis assistant as a multilabel classification task based on the analyses of obstetric EMRs. The latent Dirichlet allocation (LDA) topic and the word vector are used as features and the four multilabel classification methods, BP-MLL (backpropagation multilabel learning), RAkEL (RAndom k labELsets), MLkNN (multilabel k-nearest neighbor), and CC (chain classifier), are utilized to build the diagnosis assistant models. Experimental results conducted on real cases show that the BP-MLL achieves the best performance with an average precision up to 0.7413 ± 0.0100 when the number of label sets and the word dimensions are 71 and 100, respectively. The result of the diagnosis assistant can be introduced as a supplementary learning method for medical students. Additionally, the method can be used not only for obstetric EMRs but also for other medical records.


Assuntos
Diagnóstico por Computador/métodos , Registros Eletrônicos de Saúde , Obstetrícia/instrumentação , Obstetrícia/métodos , Adulto , Algoritmos , China , Análise por Conglomerados , Interpretação Estatística de Dados , Mineração de Dados , Feminino , Humanos , Armazenamento e Recuperação da Informação , Linguística , Idade Materna , Pessoa de Meia-Idade , Processamento de Linguagem Natural , Gravidez , Projetos de Pesquisa
5.
BMC Med Inform Decis Mak ; 18(Suppl 1): 18, 2018 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-29589571

RESUMO

BACKGROUND: De-identification is the first step to use these records for data processing or further medical investigations in electronic medical records. Consequently, a reliable automated de-identification system would be of high value. METHODS: In this paper, a method of combining text skeleton and recurrent neural network is proposed to solve the problem of de-identification. Text skeleton is the general structure of a medical record, which can help neural networks to learn better. RESULTS: We evaluated our method on three datasets involving two English datasets from i2b2 de-identification challenge and a Chinese dataset we annotated. Empirical results show that the text skeleton based method we proposed can help the network to recognize protected health information. CONCLUSIONS: The comparison between our method and state-of-the-art frameworks indicates that our method achieves high performance on the problem of medical record de-identification.


Assuntos
Anonimização de Dados , Registros Eletrônicos de Saúde , Humanos
6.
J Colloid Interface Sci ; 514: 491-495, 2018 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-29289731

RESUMO

An azobenzene with a terminal formyl group, named as (4-[(3-Formyl-4-hydroxy)phenylazo]benzene (FHPAB)), was synthesized and used to manipulate the self-assembly of diphenylalanine (FF) molecules. Two-dimensional (2D) thin slices which are composed of ordered microspheres have been constructed through supramolecular self-assembly of FF and FHPAB. The FTIR and XPS results indicate that CN covalent bond between FF and FHPAB was generated. Hydrogen bonding and strong π-π interaction between the planar FF-HFPAB conjugates are the driving force to form the FF-HFPAB 2D thin slices. Based on the results, a possible formation mechanism of the 2D thin slices was proposed. We also found that the FF-based 2D thin slices possess superhydrophobic properties, which is therefore an extension of the range of applications of peptide assembly.


Assuntos
Compostos Azo/química , Dipeptídeos/química , Microesferas , Fenilalanina/análogos & derivados , Substâncias Macromoleculares/síntese química , Substâncias Macromoleculares/química , Tamanho da Partícula , Fenilalanina/síntese química , Fenilalanina/química , Propriedades de Superfície
7.
J Am Chem Soc ; 139(11): 4185-4194, 2017 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-28240550

RESUMO

Peptide and protein fibrils have attracted an enormous amount of interests due to their relevance to many neurodegenerative diseases and their potential applications in nanotechnology. Although twisted fibrils are regarded as the key intermediate structures of thick fibrils or bundles of fibrils, the factors determining their twisting tendency and their handedness development from the molecular to the supramolecular level are still poorly understood. In this study, we have designed three pairs of enantiomeric short amphiphilic peptides: LI3LK and DI3DK, LI3DK and DI3LK, and LaI3LK and DaI3DK, and investigated the chirality of their self-assembled nanofibrils through the combined use of atomic force microscopy (AFM), circular dichroism (CD) spectroscopy, scanning electron microscopy (SEM), and molecular dynamic (MD) simulations. The results indicated that the twisted handedness of the supramolecular nanofibrils was dictated by the chirality of the hydrophilic Lys head at the C-terminal, while their characteristic CD signals were determined by the chirality of hydrophobic Ile residues. MD simulations delineated the handedness development from molecular chirality to supramolecular handedness by showing that the ß-sheets formed by LI3LK, LaI3LK, and DI3LK exhibited a propensity to twist in a left-handed direction, while the ones of DI3DK, DaI3DK, and LI3DK in a right-handed twisting orientation.


Assuntos
Aminoácidos/química , Nanoestruturas/química , Peptídeos/química , Tensoativos/química , Simulação de Dinâmica Molecular
8.
Chemistry ; 22(52): 18722-18728, 2016 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-27865005

RESUMO

Sunlight-driven dinitrogen fixation can lead to a novel concept for the production of ammonia under mild conditions. However, the efficient artificial photosynthesis of ammonia from ordinary air (instead of high pure N2 ) has never been implemented. Here, we report for the first time the intrinsic catalytic activity of Bi2 MoO6 catalyst for direct ammonia synthesis under light irradiation. The edge-exposed coordinatively unsaturated Mo atoms in an Mo-O coordination polyhedron can act as activation centers to achieve the chemisorption, activation, and photoreduction of dinitrogen efficiently. Using that insight as a starting point, through rational structure and defect engineering, the optimized Bi2 MoO6 sunlight-driven nitrogen fixation system, which simultaneously possesses robust nitrogen activation ability, excellent light-harvesting performance, and efficient charge transmission was successfully constructed. As a surprising achievement, this photocatalytic system demonstrated for the first time ultra-efficient (1.3 mmol g-1 h-1 ) and stable sunlight-driven nitrogen fixation from air in the absence of any organic scavengers.

9.
Chem Commun (Camb) ; 52(39): 6525-8, 2016 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-27026588

RESUMO

Herein, using a simple one-step method, a Bi2MoO6-based photocatalyst with novel ultrathin nanohollow structure and simultaneous sub-10 nm Bi nanoparticles and sub-1 nm graphitic nitrogen-doped carbon nanodot (NCD) modification were successfully obtained. The coordination impact of the novel structure, SPR effect of Bi nanoparticles, up-conversion performance of graphitic NCDs and cooperative electronic capture properties of Bi metal and NCDs make the hybrid simultaneously exhibit fast charge separation and broad spectrum photocatalytic activity under UV, visible and near-infrared irradiation, leading to excellent photooxidation and photoreduction performance.


Assuntos
Bismuto/química , Molibdênio/química , Nanopartículas/química , Óxidos/química , Compostos Benzidrílicos/química , Catálise , Luz , Oxirredução , Tamanho da Partícula , Fenóis/química
10.
ACS Appl Mater Interfaces ; 8(14): 8900-7, 2016 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-26998895

RESUMO

Vaterite particles are composed of particulate CaCO3 nanoparticles, which offer an ideal platform to synthesize architectures with hierarchical structure. Herein we show that mesoporous silica particles with well-defined multicompartment structure are fabricated by employing vaterite particles as templates. The obtained silica particles inherited the structure feature of vaterite and had excellent biocompatibility and biodegradability. Moreover, the silica particles were established as an efficient anticancer drugs carrier compared with hollow silica particles, which could be applied in cancer therapy in vitro and in vivo. The silica particles obtained here offer a cheap, facile, environmentally friendly avenue to assembly of hierarchical drugs carriers.


Assuntos
Portadores de Fármacos/química , Nanopartículas/administração & dosagem , Neoplasias/tratamento farmacológico , Dióxido de Silício/administração & dosagem , Animais , Linhagem Celular Tumoral , Portadores de Fármacos/administração & dosagem , Humanos , Camundongos , Nanopartículas/química , Neoplasias/patologia , Porosidade , Dióxido de Silício/química , Ensaios Antitumorais Modelo de Xenoenxerto
11.
Soft Matter ; 11(37): 7276-87, 2015 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-26274046

RESUMO

Vocal folds are complex and multilayer-structured where the main layer is widely composed of hyaluronan (HA). The viscoelasticity of HA is key to voice production in the vocal fold as it affects the initiation and maintenance of phonation. In this study a simple layer-structured surface model was set up to mimic the structure of the vocal folds. The interactions between two opposing surfaces bearing HA were measured and characterised to analyse HA's response to the normal and shear compression at a stress level similar to that in the vocal fold. From the measurements of the quartz crystal microbalance, atomic force microscopy and the surface force balance, the osmotic pressure, normal interactions, elasticity change, volume fraction, refractive index and friction of both HA and the supporting protein layer were obtained. These findings may shed light on the physical mechanism of HA function in the vocal fold and the specific role of HA as an important component in the effective treatment of the vocal fold disease.


Assuntos
Ácido Hialurônico/química , Soroalbumina Bovina/química , Elasticidade , Ácido Hialurônico/análogos & derivados , Pressão Osmótica , Técnicas de Microbalança de Cristal de Quartzo , Resistência ao Cisalhamento , Viscosidade
12.
Chem Commun (Camb) ; 51(33): 7219-21, 2015 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-25812722

RESUMO

The controlled self-assembly of diphenylalanine (FF) into unilocular and multilocular hollow spheres was successfully achieved by an ultrasound-assisted emulsion droplet template method. This novel surfactant-free emulsion droplet template method is envisaged to be applicable to other biomolecules and materials.

13.
Small ; 11(15): 1787-91, 2015 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-25405602

RESUMO

The photo-induced self-assembly of a cationic diphenylalanine peptide (CDP) is investigated using a photoswitchable sulfonic azobenzene as the manipulating unit. A reversible structural transition between a branched structure and a vesicle-like structure is observed by alternating between UV and visible light irradiation.


Assuntos
Peptídeos beta-Amiloides/química , Peptídeos/química , Fenilalanina/análogos & derivados , Peptídeos beta-Amiloides/efeitos da radiação , Peptídeos beta-Amiloides/ultraestrutura , Cátions , Cristalização/métodos , Luz , Complexos Multiproteicos/química , Complexos Multiproteicos/efeitos da radiação , Complexos Multiproteicos/ultraestrutura , Peptídeos/efeitos da radiação , Transição de Fase/efeitos da radiação , Fenilalanina/química , Fenilalanina/efeitos da radiação , Ligação Proteica/efeitos dos fármacos , Raios Ultravioleta
14.
ScientificWorldJournal ; 2014: 503895, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24688396

RESUMO

The ZnS-Bi-TiO2 composites were prepared by the sol-gel method and were characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-visible diffuse reflectance spectroscopy (UV-Vis DRS). It is found that the doped Bi as Bi(4+)/Bi(3+) species existed in composites, and the introducing of ZnS enhanced further the light absorption ability of TiO2 in visible region and reduced the recombination of photogenerated electrons and holes. As compared to pure TiO2, the ZnS-Bi-TiO2 exhibited enhanced photodegradation efficiency under xenon lamp irradiation, and the kinetic constant of methyl orange removal with ZnS-Bi-Ti-0.005 (0.0141 min(-1)) was 3.9 times greater than that of pure TiO2 (0.0029 min(-1)), which could be attributed to the existence of Bi(4+)/Bi(3+) species, the ZnS/TiO2 heterostructure.


Assuntos
Bismuto/química , Fotólise , Sulfetos/química , Titânio/química , Compostos de Zinco/química , Compostos Azo/química , Poluentes Ambientais/química , Microscopia Eletrônica de Transmissão , Espectroscopia Fotoeletrônica , Espectrofotometria Ultravioleta , Luz Solar , Difração de Raios X
15.
Chemistry ; 20(2): 499-504, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24307401

RESUMO

The preparation of 3D hierarchical nanostructures by a simple and versatile strategy of self-assembly of dopamine (DA) and phosphotungstic acid (PTA) is described. The size and morphology of the hierarchical nanostructures could be simply controlled by varying the ratio of the two components, their concentrations, and the pH of the initial Tris-HCl solution. The self-assembly of the flowerlike microspheres has been found to involve a two-stage growth process. Moreover, use of the hierarchical nanostructures as a possible carrier for an anticancer drug in chemotherapy has been explored. The nanostructures showed an intriguing pH-dependent release behavior, making them promising for applications in biomedical science.


Assuntos
Dopamina/química , Compostos de Tungstênio/química , Administração Oral , Antibióticos Antineoplásicos/administração & dosagem , Antibióticos Antineoplásicos/química , Doxorrubicina/administração & dosagem , Doxorrubicina/química , Portadores de Fármacos , Concentração de Íons de Hidrogênio , Nanoestruturas
16.
Chem Commun (Camb) ; 49(91): 10733-5, 2013 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-24104860

RESUMO

An oxygen generation core-shell structure uploading rose bengal has been fabricated by covalent assembly of catalase and alginate dialdehyde via Schiff's base. The composite can catalyze the decomposition of intracellular H2O2 to increase the concentration of O2, which effectively enhances the anticancer efficiency of photodynamic therapy in vitro.


Assuntos
Catalase/uso terapêutico , Fotoquimioterapia , Rosa Bengala/uso terapêutico , Alginatos/química , Carbonato de Cálcio , Cápsulas , Humanos , Peróxido de Hidrogênio , Células MCF-7 , Microscopia Eletrônica de Transmissão , Neoplasias/tratamento farmacológico , Fotoquimioterapia/métodos
17.
Chem Commun (Camb) ; 49(85): 9956-8, 2013 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-24036697

RESUMO

Three sulfonic azobenzenes with tiny differences in the terminal were used to manipulate the assembly of cationic dipeptides (CDP); assemblies with diverse morphologies including urchin-like, flower-like and plate-like structures were formed.


Assuntos
Compostos Azo/química , Dipeptídeos/química , Ácidos Sulfônicos/química , Cátions , Microscopia Eletrônica de Varredura , Modelos Moleculares , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Virol J ; 10: 155, 2013 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-23687964

RESUMO

BACKGROUND: A severe MD was broken out at a farm in Shandong, China, despite FC126 vaccination of the chickens at 1-day-old. The mortality of the flocks reached up to 38.3%. The infected chickens were found to have MD pathological changes, including enlargement of spleens, livers and kidneys, and tumors occured on organs later. Samples were collected from the chickens for diagnosis. METHODS: The collected samples were inoculated into primary duck embryo fibroblast (DEF) cells, and the MDV strain named SD2012-1 was isolated. In order to identify the isolate, amplification by PCR and sequencing of oncogenic Meq and vIL-8 gene were processed, the obtained sequences were compared with the sequences of reference strains, and SD2012-1 was used to challenge immunized SPF chickens. RESULTS: A very virulent MDV isolate strain, SD2012-1, was isolated from a chicken flock in Shandong Province, China, the isolate had the characteristics of very virulent MDV-1, nucleotide and deduced amino acid sequence comparisons of Meq and vIL-8 gene of SD2012-1 with those of reference strains showed SD2012-1 had high homology with MDV strains isolated from China, SD2012-1 could break through the protection provided by HVT vaccine and HVT + SB-1 vaccine immunization and caused the mortality of SPF chickens over 60%. The immune failure occured at the farm could be due to the improper selection of vaccines. SD2012-1 produced death later and the gross postmortem lesions of chickens died early and later were different. CONCLUSIONS: MDV strain SD2012-1 isolated from Shandong Province, China was found to have the characteristics of very virulent MDV-1, which could break through the protection provided by HVT vaccine and HVT + SB-1 vaccine, the virus seemed to have a long latent period, and cause different gross postmortem lesions of chickens between chickens died early and later. A better immunization way should be chosen to prevent infection of this MDV strain in field.


Assuntos
Mardivirus/isolamento & purificação , Mardivirus/patogenicidade , Doença de Marek/patologia , Doença de Marek/virologia , Estruturas Animais/patologia , Estruturas Animais/virologia , Animais , Galinhas , China/epidemiologia , DNA Viral/genética , Surtos de Doenças , Mardivirus/genética , Doença de Marek/epidemiologia , Doença de Marek/mortalidade , Dados de Sequência Molecular , Análise de Sequência de DNA , Análise de Sobrevida
19.
J Colloid Interface Sci ; 393: 126-9, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23246131

RESUMO

The porous "sponge-like" BiVO(4) films were prepared with the polystyrene (PS) as pore forming material and F-doped SnO(2) (FTO) glass as substrate. SEM observation displayed that "sponge-like" BiVO(4) film with interconnect pore structure was successfully obtained. DRS analysis indicated the light absorption ability of BiVO(4) film was enhanced by constructing porous structure. The measurement of surface area showed that porosity could elevate the surface area of the BiVO(4) film. The experiment of PEC degradation of phenol showed that the degradation rate on the porous BiVO(4) film (with 200 µL) was 2.68 times as much as that on the BiVO(4) film. The enhanced PEC performance was attributed to the increased photo absorption ability, elevated surface area, and more efficient reactant transfer.

20.
Langmuir ; 26(18): 14970-4, 2010 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-20731471

RESUMO

Gold nanoparticles stabilized with different capping agents were synthesized in a two-phase liquid-liquid system and found to self-assemble into various patterns at the air/water interface. The shapes of the patterns are closely related to the molecule structures of the capping agents. Systems with mixed capping agents were also investigated, and honeycomb patterns can be obtained in this way. T-shape and H-shape patterns were also observed. A possible mechanism based on Marangoni-Benard convection in evaporating droplets is proposed.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA