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1.
PLoS One ; 18(11): e0291652, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38019837

RESUMO

The new product development (NPD) activities of enterprises serve as a critical source of competitiveness. To effectively harness the opportunities presented by digital transformation and enhance the performance of NPD in organizations amidst the digital revolution is an area of concern that warrants attention. In this context, we conducted research using data from the annual reports of 35 listed mainboard enterprises in 2021. This research used the resource arrangement theory and the resource-structure-capability research framework. In addition, we utilized the quantitative comparative analysis (QCA) method to investigate how digital transformation capability, R&D investment capability, and heterogeneity synergies impact the performance of NPD. The findings indicate that: (1) Four distinct paths (i.e., digital innovation-driven, large-scale multi-talent, mature and robust, and digital start-up) drive improvements in NPD performance. Notably, there exists an asymmetric causal relationship between these four paths and the performance; (2) Digital transformation capability, firm R&D investment, and firm heterogeneity all contribute to enhancing NPD performance. However, they do not individually guarantee high performance. A synergistic effect of at least two factors is required to yield notable NPD performance; (3) Enterprise heterogeneity plays a pivotal role. Companies with different characteristics must opt for distinct digital transformation paths to improve their NPD performance; (4) In the initial stage of digital transformation, enterprises can enhance NPD performance by augmenting their investment in R&D personnel.


Assuntos
Investimentos em Saúde , China
2.
Materials (Basel) ; 16(9)2023 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-37176417

RESUMO

In the past few years, people have been committed to a variety of properties and functional materials, among which are nanomaterials, which have been gradually developed in-depth [...].

4.
Front Chem ; 11: 1096526, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37007056

RESUMO

In this article, 4, 4'-{1'',4''-phenylene-bis[amido-(10'' ''-oxo-10'''-hydro-9'''-oxa-10'''λ5-phosphafi-10'''-yl)-methyl]}-diphenol (P-PPD-Ph) was synthesized by a two-step synthesis, followed by the addition of various levels of epoxy chain extender (ECE) with 5 wt% of P-PPD-Ph The PLA/P-PPD-Ph/ECE conjugated flame retardant composites were produced by co-extrusion into poly(lactic acid) (PLA). The chemical structure of P-PPD-Ph was characterized by FTIR, 1H NMR and 31P NMR tests, demonstrating the successful synthesis of the phosphorus heterophilic flame retardant P-PPD-Ph. The structural, thermal, flame retardant and mechanical properties of the PLA/P-PPD-Ph/ECE conjugated flame retardant composites were characterised using FTIR, thermogravimetric analysis (TG), vertical combustion testing (UL-94), limiting oxygen index (LOI), cone calorimetry, scanning electron microscopy (SEM), elemental energy spectroscopy (EDS) and mechanical properties testing. The structural, thermal, flame retardant and mechanical properties of PLA/P-PPD-Ph/ECE conjugated flame retardant composites were characterised. The results showed that with the increase of ECE content, the residual carbon rate of the composites increased from 1.6% to 3.3%, and the LOI value increased from 29.8% to 32.6%. The cross-linking reaction between P-PPD-Ph and PLA and the increase of reaction sites led to the generation of more phosphorus-containing radicals on the PLA molecular chain, which strengthened the cohesive phase flame retardant effect of PLA flame retardant composites, and The bending strength, tensile strength and impact strength were all improved.

5.
Front Pharmacol ; 13: 1030800, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36467025

RESUMO

Acute kidney injury (AKI) is a common clinical syndrome with complex pathogenesis, characterized by a rapid decline in kidney function in the short term. Worse still, the incomplete recovery from AKI increases the risk of progression to chronic kidney disease (CKD). However, the pathogenesis and underlying mechanism remain largely unknown. Macrophages play an important role during kidney injury and tissue repair, but its role in AKI-to-CKD transition remains elusive. Herein, single nucleus RNA sequencing (snRNA-Seq) and flow cytometry validations showed that E-type prostaglandin receptor 4 (EP4) was selectively activated in renal macrophages, rather than proximal tubules, in ischemia-reperfusion injury (IRI)-induced AKI-to-CKD transition mouse model. EP4 inhibition aggravated AKI-to-CKD transition, while EP4 activation impeded the progression of AKI to CKD though regulating macrophage polarization. Mechanistically, network pharmacological analysis and subsequent experimental verifications revealed that the activated EP4 inhibited macrophage polarization through inducing Carnitine palmitoyltransferase 2 (CPT2)-mediated lipophagy in macrophages. Further, CPT2 inhibition abrogated the protective effect of EP4 on AKI-to-CKD transition. Taken together, our findings demonstrate that EP4-CPT2 signaling-mediated lipophagy in macrophages plays a pivotal role in the transition of AKI to CKD and targeting EP4-CPT2 axis could serve as a promising therapeutic approach for retarding AKI and its progression to CKD.

6.
Front Chem ; 10: 981579, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36311425

RESUMO

In this article, long fiber reinforced polybutylene terephthalate (LGF/PBT/DOPO-HQ) flame-retardant composites were prepared using 10-(2,5-dihydroxy phenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ) as the conjugated flame-retardant. The effects of different flame-retardant contents on the combustion properties of the composites were investigated. The results showed that after adding 14% of DOPO-HQ, the flame-retardant effect of the composite reached the V-0 level of UL-94 fire rating with an ultimate oxygen index (LOI) of 26.4%. The average heat release rate (Av-HRR), peak heat release rate (PHRR), and total heat release rate (THR) decreased by 45.9, 56.5, and 32.6%, respectively. This shows that LGF/PBT/DOPO-HQ composite has good flame-retardant properties. Meanwhile, the flame-retardant mechanism of cohesive phase and gas-phase synergy during the combustion of flame retardants was analyzed by carbon layer morphology and dynamic thermal decomposition.

7.
Front Chem ; 10: 1008807, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36176889

RESUMO

For polymer semiconductors, the packing ability and molecular weight of polymers play a very critical role in their optoelectronic properties and carrier transport properties. In this work, two polymers, named linear and branch, are designed and synthesized with donor-acceptor (D-A) structure, based on diketopyrrolopyrrole as an electron acceptor and carbazole as an electron donor, and applied these two polymers in organic field-effect transistors. Linear and branch have similar conjugated backbones but different molecular weights and alkyl chains. The effects of molecular weight and molecular aggregation ability on the carrier transfer efficiency are investigated. As a result, linear exhibits better aggregation ability, but due to its smaller molecular weight than branch molecule, the hole transfer efficiency of linear (1.1 × 10-2 cm2 V -1 s-1) is slightly lower than that of branch (2.3 × 10-2 cm2 V -1 s-1). This work proves that molecular weight is more important than molecular aggregation ability when designing organic field-effect transistors for polymer semiconductors.

8.
Front Chem ; 10: 956322, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35923254

RESUMO

The conjugated flame retardants have rarely been studied. A conjugate flame-retardant 4, 4'-{1″, 4″-phenylene-bis [amino- (10‴-oxy10‴-hydro-9‴-hydrogen- 10‴λ5-phosphaphenanthrene-10″-yl)-methyl]}-diphenol (P-PPD-Ph) was synthesized and added into the polylactic acid (PLA) matrix. The P-PPD-Ph-conjugated flame-retardant structure was tested by FTIR, 1H, and 31P NMR analysis. The thermal and rheological properties of PLA/P-PPD-PH-conjugated flame-retardant composites were investigated. The results showed that P-PPD-Ph-conjugated flame retardant affects PLA/P-PPD-PH-conjugated flame-retardant composites for promoting the formation of a carbon layer when the P-PPD-Ph-conjugated flame-retardant content was 15% and the residual carbon ratio for PLA/P-PPD-PH-conjugated flame-retardant composites increased by 4.2%.

9.
Front Chem ; 10: 934203, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35783214

RESUMO

A novel alternating donor-acceptor polymer PQ1 is designed and synthesized by palladium-catalyzed Stille coupling between quinoxaline as an electron-deficient unit and indacenodithiophene (IDT) as electron-rich groups. Polymer PQ1 presents not only a strong intramolecular charge transfer effect, which is beneficial for the charge transport within single molecules but also a narrow electrochemical band gap and a high highest occupied molecular orbital (HOMO) energy level. In addition, the optical absorption study indicates that the PQ1 film exhibits good aggregation, which is an advantage for the charge transport between neighboring molecules. As a consequence, PQ1 presents p-type semiconductor properties with a high hole mobility of up to 0.12 cm2 V-1 s-1. This study reveals the great potential of quinoxaline-type chromophores in constructing novel organic semiconductors.

10.
Front Chem ; 10: 933716, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35774856

RESUMO

A bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative (DiDOPO) with conjugated structure was utilized as a novel conjugated flame retardant, Polypropylene(PP)/DiDOPO conjugated flame retardant composites were papered by being melt-extruding with a twin-screw extruder. The flame retardant efficiency of PP/DiDOPO conjugated flame retardant composites were investigated by cone calorimetry, limiting oxygen index (LOI), vertical burning test (UL-94). Besides, the rheological behavior of PP/DiDOPO conjugated flame retardant composites are measured by ARES rheometer. The results showed that when the content of DiDOPO with conjugated structure was 16 wt%, the LOI values of PP/DiDOPO conjugated flame retardant composites was 24%, and PP/DiDOPO conjugated flame retardant composites reaches V-0 grade. The heat release rate (HRR), total heat release rate (THR) and CO2 of PP/DiDOPO conjugated flame retardant composites decreased, so PP/DiDOPO conjugated flame retardant composites had excellent flame retardant effect. Rheological analysis results indicated that DiDOPO with conjugated structure suppressed the melt dripping of PP/DiDOPO conjugated flame retardant composites by enhancing the melt stability. The results showed that the DiDOPO with conjugated structure can significantly enhance the flame retardancy effect of PP/DiDOPO conjugated flame retardant composites. In addition, the materials PP/DiDOPO might be with low conductivity and charge transport mobility.

11.
Front Chem ; 10: 938353, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35832464

RESUMO

Diketopyrrolopyrrole (DPP), due to its good planarity, π-conjugate structure, thermal stability, and structural modifiability, has received much attention from the scientific community as an excellent semiconductor material for its applications in the field of optoelectronics, such as organic solar cells, organic photovoltaics, and organic field effect transistors. In this study, a new small molecule, pyrrolopyrrole aza-BODIPY (PPAB), based on the thiophene-substituted DPP structure was developed using the Schiff-base formation reaction of DPP and heteroaromatic amines. Absorption spectroscopy, electrochemistry, X-ray diffraction, molecular theoretical simulation calculation were performed, and organic field-effect transistor properties based on PPAB were investigated. It was found that PPAB exhibits a broad absorption range in the visible and near-infrared regions, which is attributed to its long-range conjugate structure. In addition, it is worth noting that PPAB has multiple F atoms resulting in the low LUMO level, which is conducive to the injection and transportation of charge carriers between the semiconductor layer and the electrode. Meanwhile, its hole carrier mobility is up to 1.3 × 10-3 cm2 V-1 s-1 due to its large conjugate structure, good intramolecular charge transfer effect, and high degree of coplanarity. In this study, a new chromophore with electron-deficient ability for designing high-performance semiconductors was successfully synthesized.

12.
Front Chem ; 10: 894112, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35646831

RESUMO

The DOPO derivative-conjugated flame retardant 4, 4'-{1'', 4'' - phenylene - bis [amino - (10‴ - oxy -10‴-hydro-9‴-hydrogen-10‴ λ5 -phosphaphenanthrene-10''-yl)-methyl]}-diphenol (P-PPD-Ph) with two hydroxyl groups was synthesized. Polylactic acid conjugated flame-retardant composites with P-PPD-Ph were papered by using a twin-screw extruder. The flame-retardant properties of polylactic acid-conjugated flame-retardant composites were investigated. The flame-retardant properties of PLA-conjugated flame-retardant composites were characterized by the limiting oxygen index (LOI) and the vertical burning test (UL94). The results showed that the PLA-conjugated flame-retardant composites achieved a V-0 rating (UL-94, 3.2 mm) when the conjugated flame retardant was added at 5 wt%, and increase in LOI value from 22.5% to 31.4% relative to composites without added conjugated flame retardant. The flame-retardant mechanism of PLA-conjugated flame-retardant composites were further studied by TG-FTIR, the results showed that the P-PPD-Ph promoted the PLA-conjugated flame-retardant composites to decompose and also released fragments with quenching and dilution, which suggests that P-PPD-Ph for PLA-conjugated flame-retardant composites mainly play a role of the gas-phase flame retardant.

13.
Clin Interv Aging ; 16: 1303-1313, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34267510

RESUMO

PURPOSE: Atherosclerosis contributes substantially to cardiovascular mortality in patients with chronic kidney disease (CKD). But precise risk model for subclinical atherosclerosis in the CKD population is still lacking. The study aimed to develop and validate a nomogram for screening subclinical atherosclerosis among CKD patients without dialysis. PATIENTS AND METHODS: A total of 1452 CKD stage 1‒5 has been recruited in this cross-sectional study. Subclinical atherosclerosis was diagnosed with carotid ultrasonography. Patients were divided into the training set and validation set. The risk factors of atherosclerosis were identified by the training set and confirmed by the validation set. The receiver operating characteristic (ROC) curves and decision curve analyses (DCA) were executed to evaluate the accuracy of fitted logistic models in training and validation sets. Finally, a nomogram based on constructed logistic regression model in all participants was plotted. RESULTS: A total of 669 (46.1%) patients were diagnosed with subclinical carotid atherosclerosis. Binary logistic regression analysis showed that males, age, hypertension, diabetes, CKD stages, calcium, platelet, and albumin were risk factors for atherosclerosis. The accuracy of fitted logistic models was evaluated by the area under the ROC curve (AUC), which showed good predictive accuracy in the training set (AUC=0.764 (95% Confidence interval (CI): 0.733-0.794) and validation set (AUC=0.808 (95% CI: 0.765-0.852). A high net benefit was also proven by the DCA. Finally, these predictors were all included to generate the nomogram. CONCLUSION: This proposed nomogram shows excellent predictive ability and might have a significant clinical implication for detecting subclinical atherosclerosis in patients with CKD.


Assuntos
Aterosclerose , Insuficiência Renal Crônica , Adulto , Idoso , Aterosclerose/diagnóstico por imagem , Aterosclerose/etiologia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nomogramas , Insuficiência Renal Crônica/complicações , Fatores de Risco
14.
Nat Commun ; 11(1): 4664, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32938919

RESUMO

Cardiorenal syndrome type 4 (CRS4) is a common complication of chronic kidney disease (CKD), but the pathogenic mechanisms remain elusive. Here we report that morphological and functional changes in myocardial mitochondria are observed in CKD mice, especially decreases in oxidative phosphorylation and fatty acid metabolism. High phosphate (HP), a hallmark of CKD, contributes to myocardial energy metabolism dysfunction by downregulating peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α). Furthermore, the transcriptional factor interferon regulatory factor 1 (IRF1) is revealed as the key molecule upregulated by HP through histone H3K9 acetylation, and responsible for the HP-mediated transcriptional inhibition of PGC1α by directly binding to its promoter region. Conversely, restoration of PGC1α expression or genetic knockdown of IRF1 significantly attenuates HP-induced alterations in vitro and in vivo. These findings demonstrate that IRF1-PGC1α axis-mediated myocardial energy metabolism remodeling plays a crucial role in the pathogenesis of CRS4.


Assuntos
Síndrome Cardiorrenal/metabolismo , Fator Regulador 1 de Interferon/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Síndrome Cardiorrenal/patologia , Modelos Animais de Doenças , Regulação para Baixo , Metabolismo Energético , Técnicas de Silenciamento de Genes , Taxa de Filtração Glomerular , Glucuronidase/genética , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/metabolismo , Humanos , Fator Regulador 1 de Interferon/genética , Proteínas Klotho , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Cardíacas/patologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Fosfatos/metabolismo , Regiões Promotoras Genéticas , Ratos , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/metabolismo , Adulto Jovem
15.
Nanomaterials (Basel) ; 9(7)2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31277280

RESUMO

Silver nano-particles (AgNPs)-filled antibacterial materials have been widely employed in the fields of biology and biomedicine. However, AgNPs have shown obvious cytotoxicity. Hence it is more reasonable to use silver chloride nanoparticles (AgCl NPs) to prepare antibacterial materials due to the slow release of silver ions created by AgCl NPs formed in the chitosan. In this experiment, a useful antibacterial hydrogel for skin repairation was prepared by exploring the relationship between AgCl NPs and cytotoxicity. It is worth noting that the crosslinked network structure was successfully obtained in an antibacterial AgCl/PVA (Polyvinyl alcohol)/PEG (Polyethylene glycol)/CS (Chitosan) hydrogel materials by the hydrothermal method. In detail, the dynamic particle size distribution of AgCl NPs was relatively uniform, which is analyzed by a dynamic light scattering (DLS). The internal structure of the lyophilized hydrogel showed obvious porous structure, indicating that the hydrogel had high water content. The result of X-ray photoelectron spectroscopy (XPS) confirmed the existence of a silver element. The release concentration of silver ions was analyzed by inductively coupled plasma (ICP) to study the effect of silver ions release concentration on the antibacterial activity and cytotoxicity of hydrogel. The results show that the lower concentration of silver ions can make the hydrogel have good antibacterial activity and low cytotoxicity. The bacteriostatic rate of the antibacterial hydrogel was over 90%. Simultaneously, the mechanical properties test shows that the hydrogel has good mechanical properties, which can be widely used as an antibacterial material.

16.
Nanotechnology ; 30(29): 295101, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-30917342

RESUMO

In this study, an antibacterial degummed silk fiber (ADSF)/nano-hydroxyapatite/polylactic acid (ADSF/nHA/PLA) porous scaffold with antibacterial properties was prepared by using degummed silk fiber (DSF) loaded with silver nano-particles (Ag NPs) as a reinforcing material. In the experiment, ADSF and nHA were used as the main variables to investigate the effect of the change of the composition ratio on the performance of the composite scaffold, and a composite scaffold with excellent performance was obtained. Firstly, the DSFs were treated with dopamine (DA) and the silver ions were reduced to Ag NPs using the strong reducibility of polydopamine (PDA) to prepare ADSF loaded with Ag NPs. Finally, ADSF/nHA/PLA composite scaffolds with antibacterial properties were prepared using ADSF as a reinforcing material. In addition, samples were found to have good mineralization capacity in in vitro mineralization experiments. At the same time, in cell culture and antibacterial experiments, ADSF/nHA/PLA scaffolds were found to have good bioactivity, biocompatibility and antibacterial properties. All the results showed that the Ag NPs loaded DSF improved the performance of the nHA/PLA composite scaffold, while the ADSF/nHA/PLA had good bioactivity and antibacterial properties, making the antibacterial ADSF/nHA/PLA composite scaffold has a great potential for bone tissue engineering.


Assuntos
Antibacterianos/síntese química , Nanopartículas Metálicas/química , Seda/química , Alicerces Teciduais/química , Animais , Antibacterianos/farmacologia , Células Cultivadas , Força Compressiva , Dopamina/química , Durapatita/química , Escherichia coli/efeitos dos fármacos , Indóis/química , Nanopartículas Metálicas/ultraestrutura , Camundongos , Poliésteres/química , Polímeros/química , Porosidade , Seda/ultraestrutura , Staphylococcus aureus/efeitos dos fármacos , Engenharia Tecidual/métodos
17.
J Biomater Appl ; 33(6): 776-791, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30482129

RESUMO

Biodegradable polymers, because their degradation products are small molecules that do not cause immune system rejection, have been increasingly used by researchers to explore the preparation of scaffold with excellent mechanical properties, biocompatibility and biodegradability. In this study, nano-hydroxyapatite and polybutylene succinate were mixed by solution-blending to prepare a porous scaffold that could be used in the biomedical industry. Based on the viewpoint of bionics, porous scaffold with well pore structure and uniform dispersion of nano-hydroxyapatite particles was prepared using ethanol as a porogen. When ethanol was used as a porogen to prepare the porous scaffold, the effects of different mass ratios of nano-hydroxyapatite and polybutylene succinate on the porosity and pore structure of the porous scaffold were investigated under the same amount of ethanol. The mercury intrusion tests showed that the porosity of the 30 nano-hydroxyapatite/polybutylene succinate porous scaffold was 38.987%. The experiment results of in vitro mineralization and cell culture showed that the porous scaffolds have good osteogenic capacity and cell compatibility, including attachment and proliferation. All experiment results indicated that ethanol can be used as a porogen to prepare nano-hydroxyapatite/polybutylene succinate porous scaffold, and it has great potential as a scaffold for bone tissue engineering.


Assuntos
Materiais Biocompatíveis/química , Butileno Glicóis/química , Durapatita/química , Nanoestruturas/química , Polímeros/química , Alicerces Teciduais/química , Animais , Etanol/química , Teste de Materiais , Camundongos , Células NIH 3T3 , Nanoestruturas/ultraestrutura , Osteogênese , Engenharia Tecidual
18.
Materials (Basel) ; 11(11)2018 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-30463325

RESUMO

P(N-phenylmaleimide-alt-styrene) (P(NPMI-alt-St)) and P(N-(4-carboxyphenyl)maleimide-alt-styrene) (P(CPMI-alt-St)) were designed and synthesized via free radical copolymerization. Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (¹H NMR and 13C NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) were used to confirm the structure of P(NPMI-alt-St) and P(CPMI-alt-St). Next, the effect of P(CPMI-alt-St) on the heat deflection temperature (HDT) of nylon 6 was studied. In comparison to the PA6/P(NPMI-alt-St) blend, with the addition of 10 wt %, the HDT value of the PA6/P(CPMI-alt-St) blend increased by 15.7 °C, and the glass transition temperature (Tg) by Dynamic mechanical analysis (DMA) increased 2.3 °C. According to the analysis of DMA, dynamic viscosity, and the SEM of PA6 and its blends, P(CPMI-alt-St) promoted its compatibility with PA6, and promoted the storage modulus and dynamic viscosity of the blends. Thus, the introduction of 4-carboxyl can significantly improve the effect of P(CPMI-alt-St) on the heat resistance modification of nylon 6.

19.
Kidney Blood Press Res ; 42(6): 1205-1215, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29227975

RESUMO

BACKGROUND/AIMS: Hyperphosphatemia is one of the most notable features of chronic kidney disease (CKD). Numerous epidemiological and clinical studies have found that high serum phosphate concentrations are associated with calcification in the coronary arteries. However, the mechanisms underlying the vascular calcification induced by high phosphate have not been understood fully. METHODS: Vascular smooth muscle cells (VSMCs) were cultured in high-phosphate media to induce vascular calcification, which was detected by Alizarin red S staining. Gene expression and protein levels of differentiation markers were determined by real-time RT-PCR and western blotting, respectively. Protein levels of phosphorylated NF-κB and TLR4 were detected by western blotting, and the role of NF-κB/TLR4 was further confirmed by using an NF-κB inhibitor or TLR4 siRNA. RESULTS: Our results showed that high-phosphate media induced obvious calcification of VSMCs. Simultaneously, VSMC differentiation was confirmed by the increased expression of bone morphogenetic protein-2 and Runt-related transcription factor 2 and decreased expression of the VSMC-specific marker SM22α, which was accompanied by the increased expression of inflammatory cytokines. Moreover, a significant upregulation of TLR4 and phosphorylated NF-κB was also detected in VSMCs with high-phosphate media. In contrast, VSMC calcification and the increased expression of inflammatory cytokines were markedly attenuated by pretreatment with TLR4 siRNA and pyrrolidine dithiocarbamic acid, an NF-κB inhibitor. CONCLUSION: These data suggest that high-phosphate conditions directly induce vascular calcification via the activation of TLR4/NF-κB signaling in VSMCs. Moreover, inhibition of the TLR4/NF-κB signaling pathway might be a key intervention to prevent vascular calcification in patients with CKD.


Assuntos
Músculo Liso Vascular/metabolismo , Fosfatos/química , Fosfatos/farmacologia , Calcificação Vascular/induzido quimicamente , Células Cultivadas , Humanos , Hiperfosfatemia/complicações , NF-kappa B/metabolismo , Insuficiência Renal Crônica/metabolismo , Transdução de Sinais , Receptor 4 Toll-Like/metabolismo
20.
Materials (Basel) ; 10(5)2017 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-28772860

RESUMO

In this work, the long glass fibre-reinforced poly(butylene terephthalate) (PBT) composites filled with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) were prepared by melt blending, and the influence of thermo-oxidative ageing on the static and dynamic mechanical properties, thermal behaviours and morphology of composites with different ageing time at 120 °C were investigated and analysed. The results showed that the mechanical properties decreased in the primary stage of ageing, while embrittlement occurs in the later period, and the crystallinity of PBT decreases first, and then recovers to some extent. The scanning electron microscopy (SEM) photos of the samples indicated that the obvious crack appeared on the sample surface and a deeper, broader crack occurred with a longer ageing time. The results of energy dispersive X-ray analysis (EDAX) proved the DOPO filler diffused to the sample surface by measuring the content of phosphorus. Thermal gravimetric analysis (TGA) curves showed that the thermal stabilities of composites increased with longer ageing time, as did the values of the limited oxygen index (LOI). Meanwhile, the results of dynamic mechanical analysis (DMA) indicated that the glass transition temperature shifted to a higher temperature after ageing due to the effect of crosslinking, and both the crosslinking and degradation of PBT molecular chains act as the main factors in the whole process of thermo-oxidative ageing.

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