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1.
J Appl Toxicol ; 41(6): 941-952, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33094530

RESUMO

Cerium oxide (CeO2 ) nanoparticles have unique redox properties and exert excellent antioxidant effects in the biological environment. In recent years, many researchers have focused on the CeO2 nanoparticles as an effective antioxidant drug in the prevention and treatment of various diseases. However, the toxicity of CeO2 nanoparticles in vivo remains controversial and still needs intensive research. Therefore, the objective of this study is to investigate the pulmonary and systemic toxicity in rats after 14 days of exposure to the PEGylated CeO2 nanoparticles (abbreviated as CNPs; exposure dose of 2, 10, or 20 mg/kg) through a single intratracheal instillation (IT). We assessed the indicators of lung injury and the pathological damage degree of lung tissue. The bronchoalveolar lavage fluid (BALF) analysis and lung histopathology revealed the occurrence of slight pulmonary inflammation in the 20-mg/kg experimental group rats. However, the inflammation factors in the lung tissue of every group rats did not significantly increase, and the levels of superoxide dismutase (SOD) and glutathione (GSH) in lung tissue homogenate rose considerably in the experimental groups. Collectively, these results indicated that pulmonary exposure by the high dose of CNPs could induce mild pulmonary inflammation but did not cause severe systemic toxicity. Moreover, we speculate that the mechanism of pulmonary toxicity of CNPs in rats was due to the autophagic death of healthy lung epithelial cells mediated by endoplasmic reticulum stress. Our results implicate that CNPs can be safely used as an antioxidant drug for the oxidative stress pulmonary diseases.

2.
J Acoust Soc Am ; 148(1): EL27, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32752772

RESUMO

This letter investigates an acoustic metamaterial exhibiting a unique sound pressure amplification mechanism for ultra-low frequency sound attenuation. The system is constructed by integrating a flexible panel into the side-branch duct of a Herschel-Quincke (HQ) tube. A new peak emerges in the Sound Transmission Loss (STL) at a frequency far lower than the frequencies of the HQ tube-induced STL peaks. It cannot, after careful comparisons, be attributed to any local resonances, including structural resonances of the flexible panel or air resonances inside the side-branch cavities. To explain the underlying physics, several numerical simulations are performed. The results reveal that analog to a mechanical inerter, a "push-pull" force is created by the sound pressure difference between the sub-cavities in which a pressure amplification mechanism is generated at the interface of the embedded panel. This force is large enough to activate an out-of-plane motion of the flexible panel, trapping the incident sound power in a circular flow around the duct-branch loop. The unique phenomenon is successfully reproduced in experiment, where the flexible panel is made of carbon fiber. The proposed acoustic metamaterial can be used as silencing components for ultra-low frequency noise control in duct.

3.
Adv Healthc Mater ; 9(1): e1900948, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31746549

RESUMO

Prussian blue nanoprobes are widely studied and applied in tumor photothermal therapy (PTT) and magnetic resonance imaging (MRI), due to their low toxicity and excellent in vivo performance. However, the sizes of hitherto reported Prussian blue nanoprobes are generally larger than 50 nm, which greatly influence cell phagocytosis, in vivo circulation, and biodistribution. In this work, a novel method of doping zinc ions is used to control the size of Prussian blue nanoprobes. Consequently, the performances of the nanoprobes in PTT and MRI are both significantly improved. The results show that the minimum size of Prussian blue nanoprobes achieved by doping 10% zinc ions (abbreviated as SPBZn(10%)) is 3.8 ± 0.90 nm, and the maximum specific absorption coefficient, photothermal conversion efficiency, and longitudinal relaxation rates are 1.78 L g-1 cm-1 , 47.33%, and 18.40 mm-1 s-1 , respectively. In addition, the SPBZn(10%) nanoprobes provide excellent PTT efficacy on 4T1 tumor cells (killing rate: 90.3%) and breast cancer model (tumor inhibition rate: 69.4%). Toxicological experiment results show that the SPBZn(n%) nanoprobes exhibit no obvious in vitro cytotoxicity and they can be used safely in mice at doses below 100 mg kg-1 . Therefore, SPBZn(10%) nanoprobes can potentially be used for effective cancer theranostics.


Assuntos
Neoplasias da Mama/terapia , Ferrocianetos/química , Nanoestruturas/química , Fármacos Fotossensibilizantes/química , Terapia Fototérmica/métodos , Zinco/química , Animais , Neoplasias da Mama/diagnóstico por imagem , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Feminino , Humanos , Hipertermia Induzida , Raios Infravermelhos , Imageamento por Ressonância Magnética , Camundongos , Camundongos Endogâmicos BALB C , Tamanho da Partícula , Fármacos Fotossensibilizantes/metabolismo , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Nanomedicina Teranóstica , Distribuição Tecidual , Ensaios Antitumorais Modelo de Xenoenxerto
4.
ACS Appl Mater Interfaces ; 10(46): 39942-39951, 2018 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-30365298

RESUMO

Window glasses can block noise from outdoor, but they reverberate sound within a large indoor space. Microperforated glass absorbers have been developed to absorb sound over a fixed but narrow bandwidth. To tune the frequency spectrum of acoustic absorption, we developed a transparent tunable acoustic absorber based on microperforated dielectric elastomer actuator (MPDEA) and transparent compliant electrodes. Such transparent compliant electrodes were inkjet printed from Triton X-plasticized poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) ink, which shows improved wettability on the acrylate dielectric elastomer substrate. These transparent polymeric electrodes are softer with uptake of moisture while being self-clearable and durable. A single layer of MPDEA using two inkjet-printed electrodes is 78.64% clear, but the clarity of a two-layer MPDEA decreases to 61.8%. Among the two designs, the two-layer MPDEA exhibits a broader acoustic absorption bandwidth of 444 Hz for absorbing more than 80% of the sound energy. Inactivated resonant frequency of this MPDEA is 1170 Hz, whereas the 6 kV activation can reduce the resonant frequency for 15.2% by causing 9% hole-diameter contraction. This transparent tunable acoustic absorber can be fitted to window glass; its acoustic performance is better than that of translucent curtains.

5.
J Acoust Soc Am ; 138(3): EL236-41, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26428819

RESUMO

A duct silencer with tunable acoustic characteristics is presented in this paper. Dielectric elastomer, a smart material with lightweight, high elastic energy density and large deformation under high direct current/alternating current voltages, was used to fabricate this duct silencer. The acoustic performances and tunable mechanisms of this duct silencer were experimentally investigated. It was found that all the resonance peaks of this duct silencer could be adjusted using external control signals without any additional mechanical part. The physics of the tunable mechanism is further discussed based on the electro-mechanical interactions using finite element analysis. The present promising results also provide insight into the appropriateness of the duct silencer for possible use as next generation acoustic treatment device to replace the traditional acoustic treatment.


Assuntos
Acústica/instrumentação , Ar Condicionado/instrumentação , Elastômeros , Eletrônica/instrumentação , Ruído/prevenção & controle , Absorção Fisico-Química , Ar Condicionado/efeitos adversos , Elasticidade , Desenho de Equipamento , Propriedades de Superfície , Vibração
6.
Se Pu ; 22(3): 220-3, 2004 May.
Artigo em Chinês | MEDLINE | ID: mdl-15712901

RESUMO

The petroleum carboxylic acids in 200-420 degrees C distillate of crude oil were separated by the extraction with column chromatography on an anion exchange resin. The effect of the composition and structure of naphthenic acids on separation were studied by the infra-red (IR) spectroscopic techniques. Naphthenic acids and iso-butane reagent gas were introduced into the ion source for chemical ionization, in which the ions represented by [M + C4H9]+ were used to calculate the relative molecular mass for each acid. Based on the mass spectra of pure fatty and naphthenic acids, in combination with the z-series formula CnH(2n + z)O2, the naphthenic acids can be classified into fatty, mono-, bi- ... hexa-cyclic types. The results indicated that the relative molecular mass range of naphthenic acids in this distillates was 170-510, and the carbon number range was C10-C35. The contents of bi-cyclic and tri-cyclic naphthenic acids were higher than others.


Assuntos
Ácidos Carboxílicos/análise , Ácidos Carboxílicos/química , Cromatografia Gasosa , Petróleo/análise , Espectrometria de Massas por Ionização por Electrospray , Resinas de Troca Aniônica , Cromatografia Gasosa/métodos , Cromatografia por Troca Iônica/métodos , Estrutura Molecular , Peso Molecular , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrofotometria Infravermelho/métodos
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