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1.
Exp Gerontol ; 191: 112448, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38697555

RESUMEN

BACKGROUND: Stroke is a debilitating condition with high morbidity, disability, and mortality that significantly affects the quality of life of patients. In China, the WenYang FuYuan recipe is widely used to treat ischemic stroke. However, the underlying mechanism remains unknown, so exploring the potential mechanism of action of this formula is of great practical significance for stroke treatment. OBJECTIVE: This study employed network pharmacology, molecular docking, and in vivo experiments to clarify the active ingredients, potential targets, and molecular mechanisms of the WenYang FuYuan recipe in cerebral ischemia-reperfusion injury, with a view to providing a solid scientific foundation for the subsequent study of this recipe. MATERIALS AND METHODS: Active ingredients of the WenYang FuYuan recipe were screened using the traditional Chinese medicine systems pharmacology database and analysis platform. Network pharmacology approaches were used to explore the potential targets and mechanisms of action of the WenYang FuYuan recipe for the treatment of cerebral ischemia-reperfusion injury. The Middle Cerebral Artery Occlusion/Reperfusion 2 h Sprague Dawley rat model was prepared, and TTC staining and modified neurological severity score were applied to examine the neurological deficits in rats. HE staining and Nissl staining were applied to examine the pathological changes in rats. Immunofluorescence labeling and Elisa assay were applied to examine the expression levels of certain proteins and associated factors, while qRT-PCR and Western blotting were applied to examine the expression levels of linked proteins and mRNAs in disease-related signaling pathways. RESULTS: We identified 62 key active ingredients in the WenYang FuYuan recipe, with 222 highly significant I/R targets, forming 138 pairs of medication components and component-targets, with the top five being Quercetin, Kaempferol, Luteolin, ß-sitosterol, and Stigmasterol. The key targets included TP53, RELA, TNF, STAT1, and MAPK14 (p38MAPK). Targets related to cerebral ischemia-reperfusion injury were enriched in chemical responses, enzyme binding, endomembrane system, while enriched pathways included lipid and atherosclerosis, fluid shear stress and atherosclerosis, AGE-RAGE signaling in diabetic complications. In addition, the main five active ingredients and targets in the WenYang FuYuan recipe showed high binding affinity (e.g. Stigmasterol and MAPK14, total energy <-10.5 Kcal/mol). In animal experiments, the WenYang FuYuan recipe reduced brain tissue damage, increased the number of surviving neurons, and down-regulated S100ß and RAGE protein expression. Moreover, the relative expression levels of key targets such as TP53, RELA and p38MAPK mRNA were significantly down-regulated in the WenYang FuYuan recipe group, and serum IL-6 and TNF-a factor levels were reduced. After WenYang FuYuan recipe treatment, the AGE-RAGE signaling pathway and downstream NF-kB/p38MAPK signaling pathway-related proteins were significantly modulated. CONCLUSION: This study utilized network pharmacology, molecular docking, and animal experiments to identify the potential mechanism of the WenYang FuYuan recipe, which may be associated with the regulation of the AGE-RAGE signaling pathway and the inhibition of target proteins and mRNAs in the downstream NF-kB/p38MAPK pathway.


Asunto(s)
Modelos Animales de Enfermedad , Medicamentos Herbarios Chinos , Simulación del Acoplamiento Molecular , FN-kappa B , Farmacología en Red , Daño por Reperfusión , Transducción de Señal , Proteínas Quinasas p38 Activadas por Mitógenos , Animales , Masculino , Ratas , Isquemia Encefálica/tratamiento farmacológico , Isquemia Encefálica/metabolismo , Medicamentos Herbarios Chinos/farmacología , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Infarto de la Arteria Cerebral Media/metabolismo , FN-kappa B/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Ratas Sprague-Dawley , Receptor para Productos Finales de Glicación Avanzada/metabolismo , Daño por Reperfusión/tratamiento farmacológico , Daño por Reperfusión/metabolismo , Transducción de Señal/efectos de los fármacos
2.
Molecules ; 28(19)2023 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-37836664

RESUMEN

Novel hybrid flame retardants containing zinc hydroxystannate and carbon nanotubes (ZHS-CNTs) were synthesized using the coprecipitation method, and the structure and morphology of ZHS-CNTs were investigate using an X-ray powder diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and thermogravimetric analyzer (TGA). Then, the ZHS, CNTs and ZHS-CNTs were incorporated into EP, respectively, and the flame-retardant and smoke inhibition performance of the composites were compared and studied. Among the three composites, the EP/ZHS-CNT composites have the highest improvements on the fire resistance and smoke inhibition properties. With only 2.0 wt.% ZHS-CNT hybrids, the pHRR of EP/ZHS-CNT composite materials is reduced by 34.2% compared with EP. Moreover, the release of toxic gases including CO, CO2 and SPR from the composites was also effectively inhibited. The mechanisms of flame retardant and smoke inhibition were investigated and the improved properties were generally ascribed to the synergistic flame-retardant effects between ZHS and CNTs, the catalyzing effect of ZHS and the stable network structure of CNTs.

3.
J Colloid Interface Sci ; 640: 434-444, 2023 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-36870219

RESUMEN

It is challenging that the functionalized MXene-based nanofillers are designed to modify the inherent flammability and poor toughness of epoxy polymeric materials and further to facilitate the application of EP composites. Herein, silicon-reinforced Ti3C2Tx MXene-based nanoarchitectures (MXene@SiO2) are synthesized by simple self-growth method, and its enhancement effects on epoxy resin (EP) are investigated. The as-prepared nanoarchitectures realize homogeneous dispersion in EP matrix, indicating well performance-enhancing potential. The incorporation of MXene@SiO2 achieves improved thermal stability for EP composites with higher T-5% and lower Rmax values. Moreover, EP/2 wt% MXene@SiO2 composites obtain a 30.2% and 34.0% reduction in peak heat release rate (PHRR) and peak smoke production rate (PSPR) compared to those of pure EP, respectively, also achieving a 52.5% fall in smoke factor (SF) values and increased yield and stability of chars. The dual char-forming effects of MXene@SiO2 nanoarchitectures, including the catalytic charring of MXene and the migration of SiO2 to induce charring, are accounted for the results, as well as lamellar barrier effects. Additionally, EP/MXene@SiO2 composites achieve an enhanced storage modulus of 51.5%, along with improved tensile strength and elongation at break, compared to those of pure EP.

4.
J Colloid Interface Sci ; 630(Pt A): 343-354, 2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-36257136

RESUMEN

In this work, a bilayer nanocoating was constructed on the surface of flexible polyurethane (FPU) foam with Ti3C2 MXene and polyethyleneimine-modified silica nanoparticles (mSiO2-NP@PEI) through layer-by-layer self-assembly technology, successfully obtaining modified flexible polyurethane composites (MFPU) with excellent flame retardancy, photothermal conversion and solar water desalination properties. The structure and morphology of MFPU foams were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscope (TEM) and Scanning electron microscope (SEM). The MFPU with three coating cycles (MFPU3) had the best flame retardancy and smoke suppression performances, mainly in terms of decreased peak heat release rate (pHRR), peak smoke production rate (pSPR) and total smoke production (TSP) by 71.3 %, 62.1 % and 74.5 %, respectively, compared to those of neat FPU. In addition, MFPU foams exhibited extraordinary light-to-heat conversion and solar water desalination capabilities. MFPU3 could reach 120 °C in 138 s and its steam conversion efficiency η was as high as 89.6 %, which was 116.0 % higher than that of unmodified foam and had a 262.8 % increase over pure water. The flame retardant MFPU foams with excellent photothermal conversion efficiency will exhibit great application potential in solar water desalination and power generation.

5.
J Colloid Interface Sci ; 608(Pt 1): 853-863, 2022 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-34785460

RESUMEN

In order to improve the fire safety of epoxy resin, ZIF-8 nanoparticle in-situ decorated boron nitride nanosheet (BN-OH/ZIF-8) is fabricated via self-assembly method and then ternary integrated BN-OH/ZIF-8/PA hybrids are prepared through the chemical etching effect of phytic acid. FTIR, XRD, XPS, TEM and TGA measurements are used to characterize the structure and morphology of the nanohybrids. The researches show that BN-OH/ZIF-8/PA not only uniformly distributed in EP matrix, but also improve the thermal stability of EP. The peak heat release rate, peak smoke production rate, total smoke production values, the fire growth index and peak CO production rate obtained from cone test are significantly decreased, demonstrating the reduction of the fire hazards of EP composites containing BN-OH/ZIF-8/PA. The nano barrier effect and catalytic activity of BN-OH/ZIF-8/PA may be conducive to suppress the release of combustible volatile products and heat, facilitate the formation of graphitized carbon layer, and protect matrix from flame damage. The ternary integrated method developed in this study explores a new way to improve the flame retardant properties of EP, thereby promoting its application range.


Asunto(s)
Resinas Epoxi , Retardadores de Llama , Compuestos de Boro , Carbono , Ácido Fítico
6.
Front Aging Neurosci ; 13: 639318, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33994992

RESUMEN

Alzheimer disease (AD) is an aging-related disorder linked to endoplasmic reticulum (ER) stress. The main pathologic feature of AD is the presence of extracellular senile plaques and intraneuronal neurofibrillary tangles (NFTs) in the brain. In neurodegenerative diseases, the unfolded protein response (UPR) induced by ER stress ensures cell survival. Mesencephalic astrocyte-derived neurotrophic factor (MANF) protects against ER stress and has been implicated in the pathogenesis of AD. MANF is expressed in neurons of the brain and spinal cord. However, there have been no investigations on MANF expression in the brain of AD patients. This was addressed in the present study by immunohistochemistry, western blotting, and quantitative analyses of postmortem brain specimens. We examined the localization and expression levels of MANF in the inferior temporal gyrus of the cortex (ITGC) in AD patients (n = 5), preclinical (pre-)AD patients (n = 5), and age-matched non-dementia controls (n = 5) by double immunofluorescence labeling with antibodies against the neuron-specific nuclear protein neuronal nuclei (NeuN), ER chaperone protein 78-kDa glucose-regulated protein (GRP78), and MANF. The results showed that MANF was mainly expressed in neurons of the ITGC in all 3 groups; However, the number of MANF-positive neurons was significantly higher in pre-AD (Braak stage III/IV) and AD (Braak stage V/VI) patients than that in the control group. Thus, MANF is overexpressed in AD and pre-AD, suggesting that it can serve as a diagnostic marker for early stage disease.

7.
RSC Adv ; 11(17): 9942-9954, 2021 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-35423514

RESUMEN

In order to realize the comprehensive utilization of industrial solid waste and the treatment of water eutrophication, the flower-like magnesium hydroxide (MH) was synthesized from phosphorus tailings by sulfuric acid hydrolysis and a hydrothermal method and then was modified with a metal organic framework (MOF) to remove the phosphates enriched in water through adsorption. Both MH and MOF-modified MH (MH@MOF) presented good removal performance of phosphates. The phosphate-adsorbed composites (MH-P and MH@MOF-P) were sustainably used as effective flame retardants for thermoplastic polyurethane (TPU) at low loadings by a solution blending method. The cone calorimetry test results showed that MH@MOF-P can significantly reduce the heat release rate (HRR), smoke production rate (SPR), total smoke release (TSR), CO release rate and CO2 release rate of TPU composites, compared with those of neat TPU. The novel strategy proposed in this work is of great significance for resource recycling, environmental governance and improving fire safety of polymer materials.

8.
J Colloid Interface Sci ; 550: 210-219, 2019 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-31071524

RESUMEN

Layered molybdenum disulfide (MoS2) has received significant attention due to various applications, such as catalysis, supercapacitors, batteries, and polymer nanocomposites. However, developing highly effective MoS2-based polymer nanocomposites with superior dispersion resulting in improved thermal and flame retardant properties still remains a huge challenge. Herein, a kind of MoS2 hybrid was synthesized by the reaction of exfoliated MoS2 nanosheets with (4-carboxybutyl) triphenylphosphoniumbromide (TPP) via a cost-effective method, where TPP serves as a synergistic agent to further improve the dispersion and flame retardant efficiency of MoS2. Then the TPP-MoS2 hybrid was added to epoxy resin (EP) matrix to improve its fire safety properties. The hybrid was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The TPP-MoS2 hybrid was uniformly dispersed in the matrix, leading to significant improvement of fire safety. After the addition of 2 wt% TPP-MoS2, the char residue of the EP nanocomposites was increased by 46% compared with that of pure EP, while the peak heat release rate (PHRR) and total smoke release (TSR) were reduced by 26% and 21%, respectively. The superior dispersion of the hybrid improved the physical barrier effect of MoS2 nanosheets thereby delaying the diffusion of volatile pyrolysis products and the transmission of heat and oxygen to underlying material.

9.
J Colloid Interface Sci ; 536: 127-134, 2019 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-30366178

RESUMEN

In this work, CeO2/rGO hybrids were successfully synthesized by a facile one-step hydrothermal method to reduce fire hazards of thermoplastic polyurethane. The structure, element components and morphology of the synthesized products were characterized by XRD, FTIR, Raman spectra and TEM. Then, 2.0 wt% CeO2/rGO hybrids were incorporated into thermoplastic polyurethane matrix (TPU) to improve thermal stability, flame retardancy and smoke toxicity suppression. The introduction of CeO2/rGO hybrids could remarkably suppress heat release and smoke release, indicated by the reduction of the peak heat release rate, smoke produce rate, as well as the release rate of CO and CO2. The significant improvement in thermal stability and smoke suppression properties was mainly due to the synergistic function between physical barrier effect of rGO and catalytic effect of CeO2. This work provided an effect way to enhance the thermal stability and fire safety of TPU.

10.
J Hazard Mater ; 344: 1078-1089, 2018 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-30216967

RESUMEN

This report described a facile process for the preparation of 2D/0D MoS2-SiO2 hybrids using a simple in situ growth method, with the purpose of promoting the dispersion of MoS2 in polymer matrices and improving the properties of polymer materials. FTIR, XPS, TGA and TEM measurements were performed to characterize the structure and morphology of the synthesized hybrids which were then introduced into epoxy to reduce flammability. The hybrids dispersed well in the epoxy matrix. No obvious agglomerations were observed. In comparison with those of neat epoxy, the incorporation of a low loading of MoS2-SiO2 hybrids resulted in significant decrements in heat release rate, total heat release and volume of toxic effluents released during combustion, which indicated that the fire hazards of epoxy composites were strongly reduced. The good dispersion, labyrinth barrier effect and the catalytic effect of MoS2-SiO2 hybrids on char formation may contribute to the observed decrease in the flammability of epoxy resin.

11.
RSC Adv ; 8(63): 36114-36122, 2018 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-35558503

RESUMEN

In this work, sandwich-like structured CoAl-LDH@ZIF-67 hybrids were constructed by in situ growth of nanosized ZIF-67 crystallites on CoAl-LDH nanoplates. The structure and morphology of CoAl-LDH@ZIF-67 hybrids were represented by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Transmission Electron Microscopy (TEM). Accordingly, the hybrids were introduced into epoxy resins to explore their effect on the thermal and fire safety properties of epoxy composites. With the introduction of 2% CoAl-LDH@ZIF-67 hybrids, the T 10%, T 50% and T max values were decreased to some extent and the char residue yield was higher than that of pristine epoxy. The peak heat release rate (PHRR) of epoxy composites declined by 26.4%, in comparison with those of pure epoxy. Moreover, the quantity of smoke produced, toxic CO released and CO2 produced were suppressed markedly and decreased by 16.7%, 59.8% and 32.2%, respectively. A possible mechanism for improving fire safety was put forward based on the analysis of the carbon residues.

12.
J Hazard Mater ; 338: 343-355, 2017 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-28595156

RESUMEN

In present study, LDH/MoS2 hybrids were facilely prepared by self-assembly of exfoliated MoS2 nanosheets and LDH via electrostatic force. The structure and morphology of the LDH/MoS2 hybrids were characterized and then introduced into epoxy for reducing its fire hazards. Compared with single MoS2, LDH/MoS2 hybrids showed a more homogeneous dispersion in the epoxy matrix and no obvious agglomerates were observed. Compared with MoS2, the addition of LDH/MoS2 hybrids endowed more excellent fire resistance to epoxy matrix, which was reflected by the significantly reduced peak heat release rate, total heat release and total smoke production. A rational flame retardant mode of action for LDH/MoS2 hybrids was proposed based on the analysis of pyrolysis fragments and char residues.

13.
J Colloid Interface Sci ; 504: 158-163, 2017 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-28550745

RESUMEN

To improve the dispersion of MoS2 in polymer matrix, a facile synthesis approach was developed in this study through a synergetic effect between two kinds of nanofillers with different dimensionality. The nanohybrids based on two dimensional (2D) MoS2 and 0D silica nanospheres were fabricated by in situ growth method without any surfactants. Characterizations of the hybrid materials were done by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Solid-state 29Si nuclear magnetic resonance (NMR) spectra, transmission electron micrographs (TEM) and scanning electron microscopy (SEM). The TEM and SEM results demonstrated that the dispersibility of MoS2 was greatly improved and the agglomeration was suppressed, with the introduction of silica nanospheres.

14.
J Colloid Interface Sci ; 500: 164-171, 2017 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-28410541

RESUMEN

Significant improvements in thermal stability and fire resistance properties of polymer materials with nanofillers at low loadings hold tremendous promise for fire safety materials. In this study, a novel two dimensional (2D) graphene-like nanomaterial (VOP) was synthesized by a simple refluxing method and then modified with typical organic surfactants. Subsequently, the novel graphene-like nanomaterials were incorporated into polystyrene (PS) matrix for reducing fire hazards. The SEM and TEM images indicated that the VOP nanosheets were well dispersed throughout the matrix without obvious aggregates, leading to remarkable improvements of thermal stability and fire safety properties. With the loading of 1wt% modified VOP, the T5%, T10%, T50% and Tmax values were increased by 15, 22, 29 and 33°C, respectively. In addition, the presence of VOP nanosheets decreased the decomposition rate of PS and increased the amount of char residues. Furthermore, the peak heat release rate and total heat release of PS composites was decreased by 48.3% and 43.6%, respectively, compared to that of neat PS. The well dispersion, physical barrier effect and catalytic carbonization effect of VOP nanosheets were the main causations for the reduction of fire hazards.

15.
J Colloid Interface Sci ; 496: 334-342, 2017 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-28237751

RESUMEN

In this work, hydroxyapatite (HAP) nanorods decorated on graphene nanosheets (HAP-Gs) was synthesized by a hydrothermal method. The structure, elemental composition and morphology of the HAP-Gs hybrids were characterized by X-ray diffraction, Fourier transform infrared and Transmission electron microscopy. Subsequently, the hybrids were incorporated into poly (ε-caprolactone) (PCL) via a solution blending method. Optical images and scanning electron microscopy observation revealed not only a well dispersion of HAP-Gs hybrids but also a strong interfacial interaction between hybrids and PCL matrix. The influence of HAP-Gs hybrids on the crystallization behavior, crystal structure, thermal stability, mechanical properties and biocompatibility of the PCL nanocomposites was investigated in detail. The results showed that the crystallization temperature of PCL was enhanced obviously, but the crystal structure was not affected by the incorporation of HAP-Gs hybrids. The mechanical properties of PCL bionanocomposites were improved obviously.


Asunto(s)
Durapatita/química , Grafito/química , Nanocompuestos/química , Poliésteres/química , Materiales Biocompatibles/química , Cristalización , Humanos , Ensayo de Materiales , Fenómenos Mecánicos , Microscopía Electrónica de Rastreo , Imagen Óptica , Termodinámica , Ingeniería de Tejidos , Difracción de Rayos X
16.
J Hazard Mater ; 293: 87-96, 2015 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-25837685

RESUMEN

Novel spinel copper cobaltate (CuCo2O4)/graphitic carbon nitride (g-C3N4) (named C-CuCo2O4) nanohybrids with different weight ratios of g-C3N4 to CuCo2O4 were successfully synthesized via a facile hydrothermal method. Then the nanohybrids were added into the thermoplastic polyurethane (TPU) matrix to prepare TPU nanocomposites using a master batch-melt compounding approach. Morphological analysis indicated that CuCo2O4 nanoparticles were uniformly distributed on g-C3N4 nanosheets. Thermal analysis revealed that C-CuCo2O4-7 (proportion of g-C3N4 to CuCo2O4 of 93/7) was an optimal nanohybrid for the properties improvement of TPU. Incorporation of C-CuCo2O4-7 into TPU led to significant improvements in the onset decomposition temperature, temperature at maximal mass loss rate and char yields. The heat release rate and total heat release of TPU/C-CuCo2O4-7 decreased by 37% and 31.3%, respectively, compared with those of pure TPU. Furthermore, the amounts of pyrolysis gaseous products, including combustible volatiles and carbon monoxide (CO), were remarkably reduced, whereas, non-flammable gas (carbon dioxide) increased. Excellent dispersion of C-CuCo2O4-7 in TPU host was achieved, due to the synergistic effect between g-C3N4 and CuCo2O4. Enhancements in the thermal stability and flame retardancy were attributed to the explanations that g-C3N4 nanosheets showed the physical barrier effect and catalytic nitrogen monoxide (NO) decomposition, and that CuCo2O4 catalyzes the reaction of CO with NO and increased char residues.


Asunto(s)
Monóxido de Carbono/química , Cobalto/química , Cobre/química , Nanocompuestos/química , Nitrilos/química , Poliuretanos/química , Catálisis , Incendios , Grafito/química
17.
ACS Appl Mater Interfaces ; 7(11): 6070-81, 2015 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-25742464

RESUMEN

In the present study, carbon nanotubes (CNTs) wrapped with MoS2 nanolayers (MoS2-CNTs) were facilely synthesized to obtain advanced hybrids. The structure of the MoS2-CNT hybrids was characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy measurements. Subsequently, the MoS2-CNT hybrids were incorporated into EP for reducing fire hazards. Compared with pristine CNTs, MoS2-CNT hybrids showed good dispersion in EP matrix and no obvious aggregation of CNTs was observed. The obtained nanocomposites exhibited significant improvements in thermal properties, flame retardancy and mechanical properties, compared with those of neat EP and composites with a single CNT or MoS2. With the incorporation of 2.0 wt % of MoS2-CNT hybrids, the char residues and glass transition temperature (Tg) of the EP composite was significantly increased. Also, the addition of MoS2-CNT hybrids awarded excellent fire resistance to the EP matrix, which was evidenced by the significantly reduced peak heat release rate and total heat release. Moreover, the amount of organic volatiles from EP decomposition was obviously decreased, and the formation of toxic CO was effectively suppressed, implying the toxicity of the volatiles was reduced and smoke production was obviously suppressed. The dramatically reduced fire hazards were generally ascribed to the synergistic effect of MoS2 and CNTs, containing good dispersion of MoS2-CNT hybrids, catalytic char function of MoS2 nanolayers, and physical barrier effects of MoS2 nanolayers and CNT network structure.

18.
J Hazard Mater ; 278: 391-400, 2014 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-24997255

RESUMEN

By means of direct nucleation and growth on the surface of graphene and element doping of cobalt oxide (Co3O4) nano-particles, manganese-cobalt oxide/graphene hybrids (MnCo2O4-GNS) were synthesized to reduce fire hazards of poly(butylene terephthalate) (PBT). The structure, elemental composition and morphology of the obtained hybrids were surveyed by X-ray diffraction, X-ray photoelectron spectrometer and transmission electron microscopy, respectively. Thermogravimetric analysis was applied to simulate and study the influence of MnCo2O4-GNS hybrids on thermal degradation of PBT during combustion. The fire hazards of PBT and its composites were assessed by the cone calorimeter. The cone test results had showed that peak HRR and SPR values of MnCo2O4-GNS/PBT composites were lower than that of pure PBT and Co3O4-GNS/PBT composites. Furthermore, the incorporation of MnCo2O4-GNS hybrids gave rise to apparent decrease of pyrolysis products containing aromatic compounds, carbonyl compounds, carbon monoxide and carbon dioxide, attributed to combined impact of physical barrier for graphene and cat O4 for organic volatiles and carbon monoxide.


Asunto(s)
Cobalto/química , Grafito/química , Manganeso/química , Nanocompuestos/química , Óxidos/química , Poliésteres/química , Incendios/prevención & control , Humo
19.
ACS Appl Mater Interfaces ; 6(1): 429-37, 2014 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-24313710

RESUMEN

A series of sodium alginate (SA) nanocomposite films with different loading levels of graphitic-like carbon nitride (g-C3N4) were fabricated via the casting technique. The structure and morphology of nanocomposite films were investigated by X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. Thermogravimetric analysis results suggested that thermal stability of all the nanocomposite films was enhanced significantly, including initial thermal degradation temperature increased by 29.1 °C and half thermal degradation temperature improved by 118.2 °C. Mechanical properties characterized by tensile testing and dynamic mechanical analysis measurements were also reinforced remarkably. With addition of 6.0 wt % g-C3N4, the tensile strength of SA nanocomposite films was dramatically enhanced by 103%, while the Young's modulus remarkably increased from 60 to 3540 MPa. Moreover, the storage modulus significantly improved by 34.5% was observed at loadings as low as 2.0 wt %. These enhancements were further investigated by means of differential scanning calorimetry and real time Fourier transform infrared spectra. A new perspective of balance was proposed to explain the improvement of those properties for the first time. At lower than 1.0 wt % loading, most of the g-C3N4 nanosheets were discrete in the SA matrix, resulting in improved thermal stability and mechanical properties; above 1.0 wt % and below 6.0 wt % content, the aggregation was present in SA host coupled with insufficient hydrogen bondings limiting the barrier for heat and leading to the earlier degradation and poor dispersion; at 6.0 wt % addition, the favorable balance was established with enhanced thermal and mechanical performances. However, the balance point of 2.0 wt % from dynamic mechanical analysis was due to combination of temperature and agglomeration. The work may contribute to a potential research approach for other nanocomposites.


Asunto(s)
Biopolímeros/química , Electrólitos , Nanoestructuras , Microscopía Electrónica/métodos , Difracción de Polvo , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría
20.
J Neurosci Res ; 90(1): 267-77, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21969311

RESUMEN

Aspirin and its main metabolite salicylate are widely used to relieve pain, treat inflammatory diseases, and prevent ischemic stroke. Multiple pathways are responsible for the therapeutic actions exerted by these drugs. One of the pathways is targeting neuronal receptors/ion channels in the central nervous system. Correspondingly, increasing evidence has implicated acid-sensing ion channels (ASICs) in the processes of the diseases that are medicated by aspirin and salicylate. We therefore employed whole-cell patch-clamp recordings to examine the effects of salicylate as well as aspirin on ASICs in cultured cortical neurons of the rat. We recorded rapid and reversible inhibition of ASIC current by millimolar concentrations of aspirin and salicylate and found that salicylate reduced acidosis-induced membrane depolarization. These data suggest that ASICs in the cortex are molecular targets of high doses of aspirin and salicylate. In addition, the results from lactate dehydrogenase release measurement showed that high doses of aspirin and salicylate protected the cortical neuron from acidosis-induced neuronal injury. These findings may contribute to a better understanding of the therapeutic mechanisms of aspirin and salicylate actions in the brain and provide new evidence on aspirin and salicylate used as neuroprotective agents in the treatment of ischemic stroke.


Asunto(s)
Acidosis/metabolismo , Antiinflamatorios no Esteroideos/farmacología , Aspirina/farmacología , Corteza Cerebral/citología , Proteínas del Tejido Nervioso/fisiología , Neuronas/efectos de los fármacos , Salicilatos/farmacología , Canales de Sodio/fisiología , Canales Iónicos Sensibles al Ácido , Animales , Animales Recién Nacidos , Muerte Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Estimulación Eléctrica , Embrión de Mamíferos , Inhibición Neural/efectos de los fármacos , Técnicas de Placa-Clamp , Propidio , Ratas , Ratas Sprague-Dawley , Bloqueadores de los Canales de Sodio/farmacología , Tetrodotoxina/farmacología
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