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1.
Int J Biol Macromol ; 270(Pt 1): 132142, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38719005

RESUMO

The severe negative effects of impurities adhering to the external surface of wearable devices can significantly influence the signal transmission, performance, and lifespan of hydrogel sensors. Herein, we developed an ion-conducting hydrogel sensor with a strong adhesive side and a non-adhesive side, similar to a "semi-releasing material." This hydrogel, formulated using deep eutectic solvents obtained from choline chloride and acrylic acid, contained lignin. This versatile material, exhibiting properties similar to semi-releasing materials, was treated with an AlCl3 solution on one side. Additionally, the hydrogel was successfully used as a highly adhesive strain sensor for real-time monitoring of various human activity signals. Moreover, the hydrogel demonstrated excellent environmental tolerance and conductivity. Lignin extracted from wood flour endowed the hydrogel sensor with excellent adhesion energy (up to 427.1 J/m2) and UV resistance. Treatment of hydrogels with AlCl3 completely eliminated their adhesiveness, thereby enhancing fracture elongation and tensile strength. This improvement can be attributed to the absence of carboxyl groups and the formation of a metal-phenolic network. The implementation of this convenient and efficient strategy provides a more feasible approach to address challenges related to impurity adhesion and signal transmission in flexible wearable devices.

2.
Sci Rep ; 14(1): 661, 2024 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-38182704

RESUMO

Frozen shoulder (FS) is a common disorder often treated with Tuina, but the mechanisms involved remain unclear. We employed proteomics and phosphoproteomics to investigate the mechanisms associated with the treatment of capsule fibrosis in FS rats. We used a method composed of three weeks of cast immobilization to establish a model of FS. We then administered Tuina once daily for 14 days, evaluated glenohumeral range of motion (ROM), assessed histological changes, and identified differentially expressed proteins (DEPs) using proteomics and phosphoproteomics. This study demonstrated that Tuina could improve glenohumeral ROM and reserve capsule fibrosis in FS rats. Proteomics revealed proteins regulated by Tuina belonging to the PI3K-AKT and ECM receptor interaction signaling pathways. Phosphoproteomics detected differentially phosphorylated proteins regulated by Tuina to be enriched in the MAPK signaling pathway. The combination of proteomics and phosphoproteomics for Protein-Protein Interaction (PPI) network analysis revealed that the phosphorylation of Myh3 and Srsf1 with a node degree larger than the average degree were considered the central regulatory protein modulated by Tuina to reverse capsule fibrosis. Thbs1, Vtn, and Tenascin-W were significantly enriched in PI3K-AKT and ECM receptor interaction signaling pathways and highly expressed in model rats. Tuina resulted in reduced expression of these proteins. Our findings demonstrated some of mechanisms behind the reversal of FS capsule fibrosis following Tuina, a scientific medical therapy for FS patients.


Assuntos
Bursite , Relatório de Pesquisa , Humanos , Animais , Ratos , Fosfatidilinositol 3-Quinases , Proteômica , Proteínas Proto-Oncogênicas c-akt , Bursite/terapia
3.
J Chromatogr A ; 1714: 464503, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38104505

RESUMO

Chitosan derivatives with two different phenylcarbamate pendants at the 6-position and 2,3-positions of the glucosamine unit were synthesized by triphenylmethyl as a protective group. The regioselective chitosan derivatives were prepared corresponding to coated-type chiral packed materials (CPMs), which were evaluated with thirteen chiral compounds by high-performance liquid chromatography (HPLC). The regioselective chitosan derivatives (4aⅠ/4aⅡ, 4bⅠ/4bⅡ) bearing electron-withdrawing 3,5­chloro or 4­chloro at the 6-position can recognize 7 or 8 of the 13 enantiomers and achieve baseline separation for enantiomers 5 and 7. They exhibited better chiral recognition abilities than the other derivatives with different substituents at the 6-position and the same 3,5-dimethylphenyl substituent at the 2,3-postion. In comparison to Chit-1 featuring a 3,5-dimethylphenyl substituent at the 2,3- and 6-positions, it was observed that the combination of both an electron-withdrawing and an electron-donating substituent of the regioselective chitosan derivatives (4aⅠ/4aⅡ, 4bⅠ/4bⅡ) showed better or similar enantioseparation abilities for racemic Compounds 7 and 6, respectively. The molecular weight-performance relationship of the regioselective chitosan derivatives was investigated in detail. It was found that with increasing molecular weight, the derivatives 4aⅡ and 4bⅡ all possessed greater enantioseparation power for 4 enantiomers, such as enantiomers 4, 7, 11, and 15, than the corresponding derivatives with low molecular weights. The molecular docking simulation results showed that excellent enantioseparation power significantly depended on the combination and interaction of multiple factors, such as steric hindrance, and polarity of the substituents on the CPMs and enantiomers.


Assuntos
Quitosana , Fenilcarbamatos , Fenilcarbamatos/química , Quitosana/química , Simulação de Acoplamento Molecular , Cromatografia Líquida de Alta Pressão/métodos , Estereoisomerismo
4.
J Vis Exp ; (198)2023 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-37677036

RESUMO

Knee osteoarthritis (KOA) is mainly characterized by degenerative changes in the knee joint's cartilage and surrounding soft tissues. The efficacy of Tuina in treating KOA has been confirmed, but the underlying mechanism needs to be investigated. This study aims to establish a scientifically feasible KOA rabbit model treated with Tuina to reveal the underlying mechanisms. For this, 18, 6-month-old normal-grade male New Zealand rabbits were randomly divided into sham, model, and Tuina groups, with 6 rabbits in each group. The KOA model was established by injecting 4% papain solution into the knee joint cavity. The Tuina group was intervened with Tuina combined with the knee joint rotary correction method for 4 weeks. Only the standard grasping and fixation were performed in sham and model groups. At the end of the 1-week intervention, the knee joint range of motion (ROM) was observed, and cartilage hematoxylin-eosin (HE) staining was done. The study shows that Tuina could inhibit chondrocyte apoptosis, repair cartilage tissue, and restore knee joint ROM. In conclusion, this study demonstrates the scientific feasibility of Tuina treatment for KOA model rabbits, highlighting its potential application in the study of KOA and similar knee joint-related conditions.


Assuntos
Osteoartrite do Joelho , Masculino , Coelhos , Animais , Articulação do Joelho , Apoptose , Condrócitos , Amarelo de Eosina-(YS)
5.
J Vis Exp ; (197)2023 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-37638776

RESUMO

Frozen shoulder (FS) is a common condition with no defined optimal therapy. Tuina therapy, a traditional Chinese medicine (TCM) technique used to treat FS patients in Chinese hospitals, has demonstrated excellent results, but its mechanisms are not fully understood. Building on a previous study, this work aimed to develop a Tuina protocol for an FS rat model. We randomly divided 20 SD rats into control (C; n = 5), FS model (M; n = 5), FS model Tuina treatment (MT; n = 5), and FS model oral treatment (MO; n = 5) groups. This study used the cast immobilization method to establish the FS rat model. The effect of Tuina and oral dexamethasone on the glenohumeral range of motion (ROM) was evaluated, and the histological findings were assessed. Our study showed that Tuina and oral dexamethasone were able to improve shoulder active ROM and preserve the structure of the capsule, with Tuina therapy proving to be more effective than oral dexamethasone. In conclusion, the Tuina protocol established in this study was highly effective for FS.


Assuntos
Anti-Inflamatórios , Bursite , Dexametasona , Medicina Tradicional Chinesa , Manipulações Musculoesqueléticas , Articulação do Ombro , Animais , Ratos , Administração Oral , Bursite/tratamento farmacológico , Bursite/etiologia , Bursite/terapia , Dexametasona/administração & dosagem , Dexametasona/uso terapêutico , Ratos Sprague-Dawley , Modelos Animais de Doenças , Medicina Tradicional Chinesa/métodos , Distribuição Aleatória , Imobilização/efeitos adversos , Imobilização/métodos , Protocolos Clínicos , Manipulações Musculoesqueléticas/métodos , Moldes Cirúrgicos/efeitos adversos , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/uso terapêutico
6.
Sci Total Environ ; 897: 165341, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37414161

RESUMO

Japanese flounder (Paralichthys olivaceus) is one of cold-water species widely farmed in Asia. In recent years, the increased frequency of extreme weather events caused by global warming has led to serious impact on Japanese flounder. Therefore, it is crucial to understand the effects of representative coastal economic fish under increasing water temperature. In this study, we investigated the histological and apoptosis responses, oxidative stress and transcriptomic profile in the liver of Japanese flounder exposed to gradual temperature rise (GTR) and abrupt temperature rise (ATR). The histological results showed liver cells in ATR group were the most serious in all three groups including vacuolar degeneration and inflammatory infiltration, and had more apoptosis cells than GTR group detected by TUNEL staining. These further indicated ATR stress caused more severe damage than GTR stress. Compared with control group, the biochemical analysis showed significantly changes in two kinds of heat stress, including GPT, GOT and D-Glc in serum, ATPase, Glycogen, TG, TC, ROS, SOD and CAT in liver. In addition, the RNA-Seq was used to analyze the response mechanism in Japanese flounder liver after heat stress. A total of 313 and 644 differentially expressed genes (DEGs) were identified in GTR and ATR groups, respectively. Further pathway enrichment of these DEGs revealed that heat stress affected cell cycle, protein processing and transportation, DNA replication and other biological processes. Notably, protein processing pathway in the endoplasmic reticulum (ER) was enriched significantly in KEGG and GSEA enrichment analysis, and the expression of ATF4 and JNK was significantly up-regulated in both GTR and ATR groups, while CHOP and TRAF2 were high expressed in GTR and ATR groups, respectively. In conclusion, heat stress could cause tissue damage, inflammation, oxidative stress and ER stress in the liver of Japanese flounder. The present study would provide insight into the reference for the adaptive mechanisms of economic fish in face of increasing water temperature caused by global warming.


Assuntos
Linguado , Animais , RNA-Seq , Temperatura , Transcriptoma , Estresse Oxidativo
7.
Am J Transl Res ; 15(3): 1766-1778, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37056812

RESUMO

BACKGROUND: Tuina and Intermediate Frequency (IF) electrotherapy are commonly used treatments for frozen shoulder (FS). This study aimed to compare the clinical efficacy of Tuina and IF electrotherapy in the treatment of stage II frozen shoulder and to provide evidence-based treatment for FS. METHODS: The FS patients were randomized into two groups, the observation group, which received Tuina, and the control group, which received IF electrotherapy. The total treatment duration was 20 minutes per treatment, 3 times per week; the treatment period was 6 weeks. Assessments were performed at baseline, 3 weeks, 6 weeks, and 16 weeks after follow-up. Primary assessments included visual analog scale (VAS), Constant-Murley scale (CMS), and secondary assessments included shoulder MRI, rotator cuff muscle diffusion tensor imaging (DTI). RESULTS: A total of 57 patients participated in this study, in the observation group (n = 29) and the control group (n = 28). At the end of the 3rd and 6th weeks of treatment, Tuina was significantly more effective than IF electrotherapy in reducing the VAS score and improving the Constant-Murley total score (P<0.05), but there was no significant difference in scores between the two groups at the 16-week follow-up (P>0.05). MRI results in both groups: compared to the control group, the observation group had better results in reducing the degree of periapical edema and reducing the thickness of the axillary humeral capsule (P<0.05); and the observation group had significantly more efficacy than the control group in improving the diffusion state of water molecules in the rotator cuff muscles (P<0.05). CONCLUSION: Tuina is more effective than IF electrotherapy in improving the symptoms of FS patients as it can rapidly relieve the pain and restore the function of the affected shoulder, reduce the edema of the shoulder capsule, restore the function of the rotator cuff muscles, and shorten the natural course of FS. Name of the registry: This study was registered in the Shandong University of Traditional Chinese Medicine Affiliated Hospital; Grant No. (2021) Lun Audit No. (033) - KY; Date of registration: 2021.4.27.

8.
Polymers (Basel) ; 15(6)2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36987216

RESUMO

Bismaleimide (BMI) resin-based structural adhesives have excellent heat resistance, with important applications demonstrated in the bonding of high-temperature BMI composites. In this paper, we report an epoxy-modified BMI structural adhesive with excellent properties for bonding BMI-based CFRP. We prepared the BMI adhesive using epoxy-modified BMI as the matrix and PEK-C and core-shell polymers as synergistic tougheners. We found that the epoxy resins improve the process and bonding properties of BMI resin but slightly reduce thermal stability. PEK-C and core-shell polymers synergistically improve the toughness and bonding performances of the modified BMI adhesive system and allow the maintenance of heat resistance. The optimized BMI adhesive exhibits excellent heat resistance, with a high glass transition temperature of 208.6 °C and a high thermal degradation temperature of 425.4 °C. Most importantly, the optimized BMI adhesive exhibits satisfactory intrinsic bonding and thermal stability. It has a high shear strength of 32.0 MPa at room temperature and up to 17.9 MPa at 200 °C. The BMI adhesive-bonded composite joint has a high shear strength of 38.6 and 17.3 MPa at room temperature and 200 °C, respectively, indicating effective bonding and excellent heat resistance.

9.
Carbohydr Polym ; 296: 119888, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36087965

RESUMO

Chitosan 2-thiourea derivatives with various substituents, including 3-(methylthio)propyl, phenyl, octyl and ethoxycarbonyl, at the 2-position of the glucosamine skeleton were prepared via isothiocyanates with the above substituents. The obtained chitosan 2-thiourea derivatives without ethoxycarbonyl were then esterified to develop a new series of chitosan 2-thiourea-3,6-diphenylcarbamate derivatives. The enantioseparation properties of the obtained chitosan derivatives were examined by high-performance liquid chromatography (HPLC). These results demonstrated that these chitosan 2-[3-(methylthio)propylthiourea]-3,6-diphenylcarbamate derivatives showed attractive chiral recognition abilities, especially for dihydropyridine calcium antagonist racemates. This result was probably attributed to the fact that the 2-thiourea substituents of this series of chitosan derivatives, as well as the 3,6-phenylcarbamate substituents, provided more favorable sites, which evidently enhanced the interactions between the enantiomers and the chitosan derivatives. The mechanism involved in the enantioseparation of the chitosan 2-[3-(methylthio)propylthiourea]-3,6-diphenylcarbamate derivatives was further discussed by molecular docking simulation.


Assuntos
Quitosana , Quitosana/química , Cromatografia Líquida de Alta Pressão/métodos , Simulação de Acoplamento Molecular , Fenilcarbamatos/química , Tioureia
10.
Fish Shellfish Immunol ; 130: 453-461, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36162775

RESUMO

Dual-specificity Phosphatases (DUSPs) are not only the key regulators of dephosphorylating and inactivating mitogen-activated protein kinases (MAPKs), but play a crucial role in the immune response. However, the role of DUSP genes in Japanese flounder (PoDUSPs) is still unclear. In this study, 28 DUSP genes in Japanese flounder were identified and classified based on the whole genome database. Phylogenetic analysis and protein structure analysis revealed that DUSPs had highly conserved domains in teleosts. Molecular evolution analysis indicated that the PoDUSP genes were conservative during evolution and were functional-constrained. Meanwhile, PoDUSP genes were found to express in different embryonic and larval stages which might play the role of sentinel in healthy organisms. Furthermore, PoDUSP genes' expression profiles after temperature stress and Edwardsiella tarda (E. tarda) infection were determined in Japanese flounder without precedent, and the results demonstrated that Podusp1, Podusp2 and Podusp16 were more respective to temperature variation whereas Podusp1 and Podusp6 were more respective to E. tarda infection. In summary, our results provide useful resources for understanding the immune responsibilities of DUSP genes in flatfish.


Assuntos
Infecções por Enterobacteriaceae , Doenças dos Peixes , Linguado , Animais , Fosfatases de Especificidade Dupla/química , Edwardsiella tarda/fisiologia , Proteínas Quinases Ativadas por Mitógeno/genética , Filogenia , Temperatura
11.
Int J Mol Sci ; 23(6)2022 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-35328705

RESUMO

As an economically important flatfish in Asia, Japanese flounder is threatened by continuously rising temperatures due to global warming. To understand the molecular responses of this species to temperature stress, adult Japanese flounder individuals were treated with two kinds of heat stress-a gradual temperature rise (GTR) and an abrupt temperature rise (ATR)-in aquaria under experimental conditions. Changes in histopathology, programmed cell death levels and the oxidative stress status of gills were investigated. Histopathology showed that the damage caused by ATR stress was more serious. TUNEL signals confirmed this result, showing more programmed cell death in the ATR group. In addition, reactive oxygen species (ROS) levels and the 8-O-hDG contents of both the GTR and ATR groups increased significantly, and the total superoxide dismutase (T-SOD) activities and total antioxidant capacity (T-AOC) levels decreased in the two stressed groups, which showed damage to antioxidant systems. Meanwhile, RNA-seq was utilized to illustrate the molecular mechanisms underyling gill damage. Compared to the control group of 18 °C, 507 differentially expressed genes (DEGs) were screened in the GTR group; 341 were up-regulated and 166 were down-regulated, and pathway enrichment analysis indicated that they were involved in regulation and adaptation, including chaperone and folding catalyst pathways, the mitogen-activated protein kinase signaling (MAPK) pathway and DNA replication protein pathways. After ATR stress, 1070 DEGs were identified, 627 were up-regulated and 423 were down-regulated, and most DEGs were involved in chaperone and folding catalyst and DNA-related pathways, such as DNA replication proteins and nucleotide excision repair. The annotation of DEGs showed the great importance of heat shock proteins (HSPs) in protecting Japanese flounder from heat stress injury; 12 hsp genes were found after GTR, while 5 hsp genes were found after ATR. In summary, our study records gill dysfunction after heat stress, with different response patterns observed in the two experimental designs; chaperones were activated to defend heat stress after GTR, while replication was almost abandoned due to the severe damage consequent on ATR stress.


Assuntos
Linguado , Brânquias , Animais , Antioxidantes/metabolismo , Linguado/genética , Linguado/metabolismo , Brânquias/metabolismo , Resposta ao Choque Térmico/genética , Humanos , Transcriptoma
12.
Sci Total Environ ; 826: 154026, 2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35219675

RESUMO

Triclosan (TCS) is widely used in personal care products and has become a contaminant ubiquitously found in the aquatic environment. It is reported exposure to triclosan can cause serious toxic effects on aquatic animals. However, the molecular mechanisms about long-term exposure to TCS-induced reproductive toxicity are not well elucidated. In the present study, adult zebrafish were exposed to TCS (2, 20 and 200 µg/L) for 150 days, and then the reproductive capacity assessment, steroid hormone and VTG quantitative measurement, histopathology observation and RNA sequencing analysis were performed to investigate the effects of TCS on its reproduction. The results indicated that long-term exposure to TCS causes the regulation disorder of the endocrine system, resulting in a reduction of the number of normal germ cells, and ultimately a decrease in the hatching rate and survival rate of offspring. This study revealed the toxic effects and contributed to our deep understanding about the potential disease of TCS exposure in the aquatic environment.


Assuntos
Triclosan , Poluentes Químicos da Água , Animais , Sistema Endócrino , Reprodução , Triclosan/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/genética
13.
Aquat Toxicol ; 241: 106005, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34731643

RESUMO

Mitogen-activated protein kinase (MAPK) are a series of serine/threonine protein kinases showing evolutionary conservation, which can be activated by many stimulus signals and then transfer them from cell membrane to nucleus. MAPKs regulate a variety of biological processes, such as apoptosis, hormone signaling and immune response. In this study, 14 putative mapk genes in Japanese flounder were identified, and their basic physical and chemical properties were characterized. Phylogenetic analysis showed that mapk genes were divided into three main subfamilies, including ERK, JNK and the p38 MAPK. Selection pressure analysis revealed they were evolutionarily-constrained and undergone strong purifying selection. Gene structure and conserved protein motif comparison suggested high levels of conservation in members of mapk gene family. The expression patterns were further investigated in each embryonic and larval development stages and different tissues. In addition, RNA-seq analyses after bacteria and temperature stresses suggested mapk genes had different expression patterns. Three mapk genes showed significant differences in response to E. tarda challenge and five were induced significantly after temperature stress, indicating their potential functions. This systematic analysis provided valuable information for further understanding of the regulation mechanism of mapk gene family under different stresses in Japanese flounder.


Assuntos
Linguado , Poluentes Químicos da Água , Animais , Linguado/genética , Proteínas Quinases Ativadas por Mitógeno/genética , Filogenia , Estresse Fisiológico , Poluentes Químicos da Água/toxicidade
14.
Polymers (Basel) ; 13(20)2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34685249

RESUMO

Surface treatment is typically required to improve the bonding performance of carbon-fiber-reinforced composites. Herein, a wet peel ply was prepared using bismaleimide (BMI) resins as a matrix resin. The temperature-heating rate extrapolation method and rheological method were employed to study the reaction characteristics and viscosity-temperature characteristics of the matrix in the BMI wet peel ply. The curing temperatures of the BMI wet peel ply and the BMI prepreg were the same (200 °C), making this wet peel ply suitable for co-curing with the BMI prepreg. After treatment with the wet peel ply, the bonding strength of the BMI composite joint showed a mean shear strength of 35.5 MPa, which was 1.72% higher than that of the sanded composite and 17.5% higher than that of the composite treated with the dry peel ply. In addition, the BMI composite treated with the BMI wet peel ply exhibited good bonding stability with a coefficient of variation of 3.9. After damp-heat aging for 1440 h, the retention rate of shear strength at room-temperature was 82.3%. The relatively loosely woven carrier in the BMI wet peel ply increased the surface roughness of the composite, thus improving the bonding strength.

15.
J Chromatogr A ; 1623: 461174, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505278

RESUMO

A new class of chitosan derivatives with an isopropylthiourea at the 2-position and various carbamates at the 3,6-positions of the glucosamine skeleton was synthesized by the selective thiocarbamoylation of the 2-amino group. The chiral stationary phases (CSPs) were then prepared by coating the obtained chitosan 2-isopropylthiourea-3,6-dicarbamate derivatives onto silica gel. The enantioseparation property of the chitosan-based CSPs was assessed with twelve racemates by high-performance liquid chromatography (HPLC). The CSPs displayed a characteristic enantioseparation power, which seemed to be significantly affected by the 3,6-substituents of the glucosamine unit. The chitosan derivatives with the 3,6-diphenylcarbamate, except for 2-methylphenylcarbamate, possessed higher enantioseparation abilities than those with the 3,6-dicyclohexylcarbamate. Compared to other chitosan derivatives with 2-various substituents and commercialized Chiralcel OD, the chitosan 2-isopropylthiourea derivatives revealed a relatively higher enantioselectivity for some racemic compounds.


Assuntos
Quitosana/análogos & derivados , Cromatografia Líquida de Alta Pressão/métodos , Carbamatos/química , Celulose/análogos & derivados , Celulose/química , Glucosamina/química , Fenilcarbamatos/química , Sílica Gel/química , Estereoisomerismo , Tioureia/análogos & derivados
16.
Polymers (Basel) ; 12(3)2020 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-32121345

RESUMO

The design and development of thermal insulation materials is very important for the treatment of offshore oil pipelines. Understanding thermal energy transport in thermal insulation materials and predicting their thermal conductivities have important theoretical and practical value for the design of thermal insulation materials. In this work, lightweight and thermally insulated (LWTI) composites with the desired mechanical strength for offshore oil pipelines applications were prepared using epoxy resin (EP) as the matrix and hollow glass microspheres (HGMs) as the filler. The morphology, density, and mechanical properties of HGM/EP LWTI composites were studied first. The flexural strength and the flexural modulus of HGM/EP LWTI composites could still be as high as 22.34 ± 2.75 Mpa and 1.34 ± 0.03 GPa, respectively, while the density was only 0.591 g/cm3. The relationship between the effective thermal conductivity of HGM/EP LWTI composites and material parameters (sizes and contents together) has been studied systematically. A three-phase prediction model was built using the self-consistent approximation method to predict the effective thermal conductivity of HGM/EP LWTI composites, and the resin matrix, the wall thickness, the HGM particle size, and other parameters (such as air) were fully considered during the derivation of this three-phase thermal conductivity model. Finally, the insulation mechanism of HGM/EP LWTI composites was systematically analyzed. The thermal conductivities of HGM/EP LWTI composites with different diameters and HGM contents calculated by the three-phase prediction model agreed well with the experimental test results, with a minimum error of only 0.69%. Thus, this three-phase thermal conductivity model can be used to theoretically simulate the thermal conductivity of epoxy resin-based LWTI composites and can be the theoretical basis for the design and prediction of the thermal conductivity of other similar hollow spheres filled materials.

17.
Nanoscale ; 12(6): 3795-3802, 2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-31994570

RESUMO

As a new family of two-dimensional materials, MXenes have attracted increasing attention in recent years due to their widespread potential applications. In contrast to early transition metals in convention, here we expand the M element of MXene to the rare earth element lutetium. Based on the first-principles density functional calculations, the bare lutetium-based carbide MXene Lu2C is determined to be stabilized in the T-type configuration. Furthermore, both fluorine and hydroxyl terminated configurations are found to be semiconductors, and their band gaps are suitable for use in semiconductors and visible and near-infrared optical devices. The Lu2C(OH)2 configuration shows a direct band gap and possesses an ultralow work function of 1.4 eV. Both Lu2CT2 (T = F, OH) MXenes exhibit high carrier mobilities. Particularly, the electron mobility of the Lu2C(OH)2 MXene is found to be anisotropic at room temperature, with values as high as 95.19 × 103 and 217.1 × 103 cm2 V-1·s-1 in the zigzag and armchair directions, respectively, which makes Lu2C(OH)2 a promising material for nanodevices. Based on these predicted properties, our work widens the range of MXene materials and their applications in semiconducting devices.

18.
Polymers (Basel) ; 11(4)2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30991635

RESUMO

In this study, the curing kinetics of the phenolic amine/epoxy resin system were investigated by nonisothermal differential scanning calorimetry (DSC). The model-free isoconversional method of Ozawa-Flynn-Wall reveals a dependence of Eα (activation energy) on conversion (α), which interprets the autocatalytic curing reaction mechanism of the phenolic amine/epoxy resin system. Studies on the effects of nano-SiO2 particles on the tensile properties and tensile fracture face morphology of nanocomposites show that the uniform dispersion of SiO2 nanoparticles plays an important role in promoting the tensile performance of nanocomposites. Additionally, increases of 184.1% and 217.2% were achieved by adding 1.5% weight parts of nano-SiO2 in composites for the tensile strength and tensile modulus, respectively.

19.
Nanomaterials (Basel) ; 8(12)2018 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-30477224

RESUMO

Self-assembled buckypapers have been successfully prepared using sodium carboxyl methyl cellulose (CMC) as a binder. The lowest resistivity that was reached was 0.43 ± 0.03 Ω·m, when the buckypapers were prepared by the same mass of CMC and carboxy-modified carbon nanotubes (CNTs). A heat-resistant electroconductive nanocomposite with epoxy resin as the matrix and CMC/buckypapers as the reinforcement was fabricated by a resin impregnation molding technique. The effects of CMC/buckypaper layers on the conductivity, thermal stability, and mechanical and dynamic mechanical performance of the epoxy resin polymer nanocomposites were investigated. It was found that CMC/buckypapers hold great promise for improving the properties of nanocomposites, and the buckypapers' performance can be enhanced by using modified CNTs to prepare them. The obtained nanocomposites showed an approximate 71.23% bending strength improvement (125.04 ± 5.62 MPa) and a 30.71% bending modulus improvement (5.83 ± 0.68 GPa), with an increased number of CMC/buckypaper layers. An enhanced degradation temperature and residual mass were also achieved for the nanocomposites when compared with a pure polymer. The nanocomposites with four CMC/buckypaper layers possessed the highest storage modulus (1934 MPa), which was approximately 60% higher than that of a neat polymer (1185 MPa). Therefore, CMC/buckypapers could be effectively used to manufacture heat-resistant electroconductive polymer nanocomposites with improved properties.

20.
J Biochem Mol Toxicol ; 32(4): e22044, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29457851

RESUMO

Accumulating evidence has reported that microRNA-144-3p (miR-144-3p) is highly related to oxidative stress and apoptosis. However, little is known regarding its role in cerebral ischemia/reperfusion-induced neuronal injury. Herein, our results showed that miR-144-3p expression was significantly downregulated in neurons following oxygen-glucose deprivation and reoxygenation (OGD/R) treatment. Overexpression of miR-144-3p markedly reduced cell viability, promoted cell apoptosis, and increased oxidative stress in neurons with OGD/R treatment, whereas downregulation of miR-144-3p protected neurons against OGD/R-induced injury. Brahma-related gene 1 (Brg1) was identified as a potential target gene of miR-144-3p. Moreover, downregulation of miR-144-3p promoted the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased antioxidant response element (ARE) activity. However, knockdown of Brg1 significantly abrogated the neuroprotective effects of miR-144-3p downregulation. Overall, our results suggest that miR-144-3p contributes to OGD/R-induced neuronal injury in vitro through negatively regulating Brg1/Nrf2/ARE signaling.


Assuntos
Elementos de Resposta Antioxidante , DNA Helicases/metabolismo , Glucose/farmacologia , MicroRNAs/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Neurônios/metabolismo , Proteínas Nucleares/metabolismo , Traumatismo por Reperfusão/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Animais , DNA Helicases/genética , Técnicas de Silenciamento de Genes , Camundongos , MicroRNAs/genética , Fator 2 Relacionado a NF-E2/genética , Neurônios/patologia , Proteínas Nucleares/genética , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/prevenção & controle , Fatores de Transcrição/genética
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