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1.
Langmuir ; 40(29): 15013-15022, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-38991116

RESUMO

Due to their unique microstructure and modifiable rheological properties, wormlike micelles that respond to environmental stimulation have garnered significant interest in recent years. Among them, CO2-responsive wormlike micelles have the advantages of simple preparation and controllable properties, which have significant development potential in the food chemistry field of thickeners. In this study, CO2-responsive wormlike micelles were prepared using docosahexaenoic acid (DHA), pyridoxamine (PA), and glucosamine (GA); the stimulus-responsive behaviors and mechanisms of the two systems, namely, NaDHA/PA and NaDHA/GA, were investigated using dynamic light scattering (DLS) and cryo-transmission electron microscopy (Cryo-TEM). The nearly unaltered viscosity of the systems confirmed the cyclic reversibility of the CO2 response of the two systems when the two mixed solutions were converted back to aqueous liquids 10 times. The preparation and properties of DHA-based CO2-responsive wormlike micelles are expected to advance fundamental research and establish the theoretical groundwork for their practical application in controllable thickening agents in food chemistry.

2.
Langmuir ; 30(35): 10557-61, 2014 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-25136957

RESUMO

An Fe3O4 nanoparticle/polymer hybrid microbubble was developed using a facile self-assembly approach. This approach involves two steps, including the initial fabrication of the iron oxide nanoparticle (IONP)/polymer hybrid microcapsules via self-assembly and a subsequent gas-filling process to yield the final microbubbles. Both in vitro and in vivo experiments demonstrated that the composite gas-filled microbubbles exhibit excellent T2-weighted magnetic resonance imaging (MRI) enhancement as well as ultrasound (US) imaging enhancement capabilities. Besides, this flexible approach allows the facile control of the microbubbles' size and thus the imaging capabilities of the microbubbles through the tuning of the molar ratio between the precursors.


Assuntos
Meios de Contraste/química , Compostos Férricos , Imageamento por Ressonância Magnética , Microbolhas , Polímeros/química , Compostos Férricos/química
3.
PeerJ Comput Sci ; 10: e1881, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38435551

RESUMO

Locomotion mode recognition in humans is fundamental for flexible control in wearable-powered exoskeleton robots. This article proposes a hybrid model that combines a dense convolutional network (DenseNet) and long short-term memory (LSTM) with a channel attention mechanism (SENet) for locomotion mode recognition. DenseNet can automatically extract deep-level features from data, while LSTM effectively captures long-dependent information in time series. To evaluate the validity of the hybrid model, inertial measurement units (IMUs) and pressure sensors were used to obtain motion data from 15 subjects. Five locomotion modes were tested for the hybrid model, such as level ground walking, stair ascending, stair descending, ramp ascending, and ramp descending. Furthermore, the data features of the ramp were inconspicuous, leading to large recognition errors. To address this challenge, the SENet module was incorporated, which improved recognition rates to some extent. The proposed model automatically extracted the features and achieved an average recognition rate of 97.93%. Compared with known algorithms, the proposed model has substantial recognition results and robustness. This work holds promising potential for applications such as limb support and weight bearing.

4.
J Colloid Interface Sci ; 482: 95-104, 2016 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-27497230

RESUMO

Fe3O4/polymer hybrid microcapsules were prepared via a template-free route which is based on polyamine-salt aggregates (PSAs) self-assembly approach. The measurements of transmission electron microscopy (TEM) indicated that the diameter and shell thickness of the microcapsules could be tuned by varying the experimental conditions, such as the concentration of reactants and evolution time employed during the PSA assembly. The results of vibrating sample magnetometer (VSM) demonstrated that the magnetic nanoparticles content of the synthesized microcapsules was tunable and all samples exhibited superparamagnetic behavior. After filling appropriate perfluorocarbon into the inner cavities of the microcapsules, the biomedical applications of the resultant microbubbles, including ultrasonic imaging (USI) and magnetic resonance imaging (MRI), were studied in vitro. It showed that the synthesized magnetic microbubbles possessed both strong ultrasound contrast enhancement capability and high relaxation rate. The excellent acoustic and magnetic properties of these self-assembled microbubbles ensure that the Fe3O4/polymer hybrid microbubbles have great potential as MRI/USI dual-modality contrast agents.


Assuntos
Meios de Contraste/química , Óxido Ferroso-Férrico/química , Imageamento por Ressonância Magnética/métodos , Nanopartículas de Magnetita/química , Microbolhas , Ultrassonografia/métodos , Acústica , Cápsulas/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Meios de Contraste/farmacologia , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Óxido Ferroso-Férrico/farmacologia , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fluorocarbonos/química , Humanos , Nanopartículas de Magnetita/ultraestrutura , Poliaminas/química
5.
Acta Biomater ; 24: 266-78, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26112374

RESUMO

In this work, superparamagnetic self-assembled microbubbles (SAMBs) consisting of "Poly(acrylic acid)-Iron oxide nanoparticles-Polyamine" sandwich-like shells and tetradecafluorohexane cores were fabricated by a template-free self-assembly approach. The SAMBs exhibit not only magnetic resonance (MR) T2 imaging functionality, but also ultrasound (US) image contrast, showing great potential as US/MR dual contrast agents. The diameters of the SAMBs can be tuned easily from 450nm to 1300nm by changing the precursor ratio, and this size variation directly affects their in vitro MRI and US signals. The SAMBs also exhibit in vivo contrast enhancement capabilities in rat liver with injection through portal vein, for both MR and US imaging. Additionally, the biodistribution of SAMBs over time suggests normal systemic metabolic activity through the spleen. The results show that the Fe content in rat liver reduces to a level of which Fe cannot be detected in 45days. The SAMBs exhibit no obvious damage to the primary organs of rat during the metabolic process, indicating their good biocompatibility in vivo.


Assuntos
Meios de Contraste/farmacologia , Fígado , Imageamento por Ressonância Magnética/métodos , Microbolhas , Nanopartículas , Ultrassonografia/métodos , Resinas Acrílicas/química , Resinas Acrílicas/farmacocinética , Resinas Acrílicas/farmacologia , Animais , Meios de Contraste/química , Meios de Contraste/farmacocinética , Compostos Férricos/química , Compostos Férricos/farmacocinética , Compostos Férricos/farmacologia , Fígado/diagnóstico por imagem , Masculino , Radiografia , Ratos , Ratos Sprague-Dawley
6.
J Mater Chem B ; 2(47): 8310-8313, 2014 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-32262000

RESUMO

Quantum dot (QD)-encoded magnetic barcodes were prepared through a highly efficient membrane emulsification-solvent evaporation approach. Our study demonstrates the great potential of these QD-encoded magnetic barcodes for both magnetic separation and multiplex suspension assays.

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