Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Carbohydr Polym ; 334: 122034, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38553233

RESUMO

Cryogels that are constructed with cellulose nanofibrils (CNF) are important as green materials for a wide range of applications. However, their utilization is limited by inherent hydrophilicity and insufficient mechanical properties. Herein, a processable CNF/nanochitin (NCh)-stabilized Pickering emulsion that contains polylactide (PLA) in the oil phase is developed to directly produce ternary composite cryogels via freeze-drying. The complexation of CNF with NCh promotes CNF adsorption at the surface of PLA droplets, resulting in formation of uniform Pickering PLA droplets. The CNF/NCh complex-stabilized PLA droplets are easy to be translated to the internal structure of the cryogels, exhibiting lightweight nature and possessing highly porous structure. The interconnected network and lamellar structure formed by the CNF/NCh complexes, associating with inclusion of PLA particles, improve the cryogel structure integrity upon post-processing and endow hydrophilic cryogel with water resistance. This study offers a straightforward and eco-friendly Pickering emulsion template on fabrication of the CNF-based composite cryogel with controllable microstructure and mechanical performance, broadening construction of nanocellulose-based composites.

2.
Langmuir ; 39(15): 5364-5374, 2023 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-37011410

RESUMO

To prevent negative effects of smoking, there is constant research on the development of various types of sustainable filter materials, capable of removing toxic compounds present in cigarette smoke. Because of the extraordinary porosity and adsorption properties, metal-organic frameworks (MOFs) represent promising adsorbents for volatile toxic molecules such as nicotine. This study reports new hybrid materials wherein six types of common MOFs of different porosity and particle size are incorporated into sustainable cellulose fiber from bamboo pulp, resulting in a series of cellulose filter samples abbreviated as MOF@CF. The obtained hybrid cellulose filters were fully characterized and investigated in nicotine adsorption from cigarette smoke, using a specially designed experimental setup. The results revealed that the UiO-66@CF material features the best mechanical performance, facile recyclability, and excellent nicotine adsorption efficiency that attains 90% with relative standard deviations lower than 8.80%. This phenomenon may be caused by the large pore size, open metal sites, and high loading of UiO-66 in cellulose filters. Additionally, the high adsorption capacity showed almost 85% removal of nicotine after the third adsorption cycle. The DFT calculation methods allowed further investigation of the nicotine adsorption mechanism, showing that the energy difference between HOMO and LUMO for UiO-66 was the closest to that of nicotine, which further proves the adsorption ability of nicotine by this material. Owing to the flexibility, recyclability, and excellent adsorption performance, the prepared hybrid MOF@CF materials may find prospective applications in nicotine adsorption from cigarette smoke.

3.
J Org Chem ; 87(11): 7193-7201, 2022 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-35579210

RESUMO

The present work focuses on a theoretical investigation of mechanistic features, chemoselectivity, regioselectivity, and effect of substituents in the gold-catalyzed reactions of alkynyl thioethers and isoxazoles. The DFT calculations reveal that the nucleophilic attack of isoxazole to a ß-position of catalyst-bound ynamide forms a vinyl intermediate. This undergoes cleavage of the N-O isoxazole bond and isomerizes to form an α-imino α'-sulfenyl gold carbene complex with stabilization of the Au-S interaction. For 3,5-dimethylisoxazole, the reaction follows a formal [3 + 2] cycloaddition pathway and a 1,3-H migration to give the pyrrole products. Replacement of 3,5-dimethylisoxazole by 3,5-dimethyl-4-phenylisoxazole leads to the formation of deacylative annulation products and desulfenylated 3-acylated pyrroles. Reactions with 4-methyl-3,5-diphenylisoxazoles induce the formation of N-acylated pyrroles and desulfenylated 3-acylated pyrroles. For the minor pathway, the α-addition and 1,2-S migration result in sulfur-substituted ß-keto enamide derivatives. In addition, the unique features of regio- and chemoselectivity were rationalized by the distortion and interaction analysis. Apart from fully rationalizing the experimental results, the theoretical DFT data give an important support for comprehending related types of reaction mechanisms.


Assuntos
Ouro , Sulfetos , Catálise , Ouro/química , Isoxazóis , Pirróis/química , Racionalização
4.
Toxicol Lett ; 358: 6-16, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35032610

RESUMO

Early experimental studies have demonstrated that microcystin-leucine arginine (MC-LR) is able to induce multiple organ damage. Female reproductive disorders caused by MC-LR have attracted increased attention in recent years. However, the underlying mechanisms of female reproductive malfunctions are not yet fully understood. Our previous study confirmed that MC-LR could enter mice ovary, induce apoptosis of ovarian granulosa cell and lead to follicular atresia. Research shows that ovary inflammation is positively related to the decline of female reproductive function. This study was aimed to find out the relationship between inflammation response and ovarian injury caused by MC-LR. MC-LR were administrated at 0, 7.5, 22.5 and 45 µg/kg for two weeks by intraperitoneal injection in female BALB/c mice. Histopathological analysis of ovary was performed. We found that MC-LR exposure induced inflammation response and fibrosis in ovary. In the present study, we observed that MC-LR could enter ovary and was mainly distributed in mGCs (mouse ovarian granulosa cells), but not in the theca-interstitial cells. We isolated and cultured mGCs with different concentrations of MC-LR at 0, 0.01, 0.1, 1 and 10 µM. MC-LR exposure caused mitochondrial DNA (mtDNA) leakage which was detected by qPCR andimmunofluorescence staining. Subsequently, mtDNA leakage activated cGAS-STING signaling, leading to elevated production of inflammatory cytokines TNF-α in mGCs.Diffusion of TNF-α in ovary resulted in inflammatory cell infiltration and interstitial cell proliferation. Ovarian inflammation provides a new perspective to explore the underlying mechanisms associated with MC-LR-induced female reproductive dysfunction.


Assuntos
Arginina , Microcistinas , Animais , Citocinas , DNA Mitocondrial , Feminino , Atresia Folicular , Células da Granulosa , Inflamação/induzido quimicamente , Leucina , Toxinas Marinhas , Camundongos , Camundongos Endogâmicos BALB C , Microcistinas/toxicidade , Nucleotidiltransferases , Fator de Necrose Tumoral alfa
5.
Ecotoxicol Environ Saf ; 212: 111931, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33508714

RESUMO

Microcystin-LR (MC-LR) is a cyclic heptapeptide; it is an intracellular toxin released by cyanobacteria that exhibits strong reproductive toxicity. Previous studies have demonstrated that MC-LR induces oxidative stress in granulosa cells by damaging the mitochondria, which eventually leads to follicle atresia and female subfertility. In the present study, granulosa cells were exposed to 0, 0.01, 0.1 and 1 µM MC-LR. After 24 h, we observed changes in mitochondrial cristae morphology and dynamics by analyzing the results of mitochondrial transmission electron microscopy and detecting the expression of DRP1. We also evaluated glucose intake using biochemical assays and expression of glucose transport related proteins. MC-LR exposure resulted in mitochondrial fragmentation and glucose intake decrease in granulosa cells, as shown by increasing mitochondrial fission via dynamin-related protein 1 (DRP1) upregulation and decreasing glucose transporter 1 and 4 (GLUT1 and GLUT4). Furthermore, the expression levels of forkhead box protein M1 (FOXM1) significantly increased due to the overproduction of reactive oxygen species (ROS) after MC-LR exposure. Our results proved that MC-LR exposure causes mitochondrial fragmentation and glucose intake decrease in granulosa cells, which provides new insights to study the molecular mechanism of female reproductive toxicity induced by MC-LR.


Assuntos
Glucose/metabolismo , Toxinas Marinhas/toxicidade , Microcistinas/toxicidade , Mitocôndrias/efeitos dos fármacos , Animais , Cianobactérias/metabolismo , Feminino , Células da Granulosa/metabolismo , Mitocôndrias/metabolismo , Mitocôndrias/fisiologia , Dinâmica Mitocondrial , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo
6.
ACS Omega ; 5(49): 31665-31672, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33344818

RESUMO

The effective removal of chlorine ion from the desulfurization slurry is of great significance to the stable operation of the desulfurization system. Modified fly ash hydrotalcites were prepared by alkali/acid-combined roasting and microwaving and used as an adsorbent for chlorine ion in desulfurized wastewater. The specific surface area and porosity of different adsorbents were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impacts of pH, temperature, adsorbent dosage, and adsorption shaking time on adsorption performance were investigated. Results showed the alkali-combined roasting-modified fly ash hydrotalcite has the optimum removal effect on Cl-. The optimal adsorption performance was achieved when the pH was 8, the adsorption temperature was 60 °C, the mass concentration of adsorbent was 10 g/L, the adsorption shaking time was 180 min, and the removal percentage of Cl- was 68.1%. The adsorption isotherm was consistent with the Langmuir isotherm model, and the adsorption saturation was 694.4 mg/g, which belonged to monolayer adsorption.

7.
Virus Res ; 286: 198072, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32659307

RESUMO

Deformed wing virus (DWV) interacting with Varroa destructor is a possible cause of honeybee colony mortality. VP2 is the structural protein of DWV but its function remains unknown. To clarify the function of VP2 and screen for novel binding proteins that interact with VP2, we carried out a membrane protein yeast two-hybrid screening using VP2 as bait. Subsequently, the interaction between VP2 and the host interacting protein [heat shock protein 10 (Hsp10)] was further verified using glutathione S-transferase pull-down assay in vitro and co-immunoprecipitation assay in cells. Furthermore, fluorescence confocal microscopy revealed that VP2 and Hsp10 were mainly co-localized in the cytoplasm. Using real-time polymerase chain reaction, we found that Hsp10 expression in DWV-infected worker honey bees were downregulated compared with that in healthy honey bees. Additionally, we showed that overexpression of VP2 protein could reduce the expression of Hsp10. These results suggest that Hsp10 plays a vital role in host immunity and antiviral effects.


Assuntos
Abelhas/genética , Proteínas do Capsídeo/metabolismo , Chaperonina 10/metabolismo , Proteínas de Insetos/metabolismo , Vírus de RNA/química , Animais , Abelhas/virologia , Proteínas do Capsídeo/genética , Chaperonina 10/genética , Proteínas de Insetos/genética , Vírus de RNA/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/virologia , Técnicas do Sistema de Duplo-Híbrido
8.
Small ; 16(8): e1906076, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31984674

RESUMO

The pursuit of high reversible capacity and long cycle life for rechargeable batteries has gained extensive attention in recent years, and the development of applicable electrode materials is the key point. Herein, thanks to the preintercalation of lithium ions, a stable and highly conductive nanostructure of V2 C MXene is successfully fabricated via a facile self-discharge mechanism, which provides open spaces for rapid ion diffusion and guarantees fast electron transport. Taking the prelithiated V2 C as electrode, an outstanding initial coulombic efficiency of 80% and an impressive capacity retention of ≈98% after 5000 charge/discharge cycles are achieved for lithium-ion batteries. Especially, it demonstrates a fascinating reversible capacity of up to 230.3 mA h g-1 at 0.02 A g-1 and a long cycling life of 82% capacity retention over 480 cycles in the hybrid magnesium/lithium-ion batteries. In addition, the Mg2+ and Li+ ions cointercalation mechanism of the prelithiated V2 C is elucidated through ex situ X-ray diffraction and X-ray photoelectron spectroscopy characterizations. This work not only offers an effective approach to compensate the large initial lithium loss of high-capacity anode materials but also opens up a new and viable avenue to develop promising hybrid Mg/Li-storage materials with eminent electrochemical performance.

9.
Environ Sci Pollut Res Int ; 26(22): 22264-22272, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31152428

RESUMO

The use of modified fly ash for preparing porous sound-absorbing materials and the optimum conditions of fly ash modification were studied. The effects of sintering temperature, sintering time, forming pressure, and other experimental conditions on porous sound-absorbing materials were also investigated. Results showed that the average volume density of the finished product was 0.93 g/cm3, the compressive strength was approximately 1.2 MPa, and the average porosity was nearly 60%. The average sound absorption coefficient of the sample in a low-frequency band was approximately 0.353, and the overall average sound absorption coefficient was nearly 0.458. The optimal preparation conditions were as follows: sintering temperature was 1100 °C, sintering time was 5 h, and molding pressure was 2 MPa.


Assuntos
Cinza de Carvão/análise , Porosidade , Força Compressiva , Temperatura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...