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1.
Nat Methods ; 2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35577954

RESUMO

Spatial transcriptomics approaches have substantially advanced our capacity to detect the spatial distribution of RNA transcripts in tissues, yet it remains challenging to characterize whole-transcriptome-level data for single cells in space. Addressing this need, researchers have developed integration methods to combine spatial transcriptomic data with single-cell RNA-seq data to predict the spatial distribution of undetected transcripts and/or perform cell type deconvolution of spots in histological sections. However, to date, no independent studies have comparatively analyzed these integration methods to benchmark their performance. Here we present benchmarking of 16 integration methods using 45 paired datasets (comprising both spatial transcriptomics and scRNA-seq data) and 32 simulated datasets. We found that Tangram, gimVI, and SpaGE outperformed other integration methods for predicting the spatial distribution of RNA transcripts, whereas Cell2location, SpatialDWLS, and RCTD are the top-performing methods for the cell type deconvolution of spots. We provide a benchmark pipeline to help researchers select optimal integration methods to process their datasets.

2.
Bioengineered ; 13(5): 12489-12503, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35579419

RESUMO

Genome-derived microRNAs (miRNAs or miRs) control post-transcriptional gene expression critical for various cellular processes. Recently, we have invented a novel platform technology to achieve high-yield production of fully humanized, bioengineered miRNA agents (hBERAs) for research and development. This study is aimed to produce and utilize a new biologic miR-34a-5p (or miR-34a) molecule, namely, hBERA/miR-34a, to delineate the role of miR-34a-5p in the regulation of mitochondrial functions in human carcinoma cells. Bioengineered hBERA/miR-34a was produced through in vivo fermentation production and purified by anion exchange fast protein liquid chromatography. hEBRA/miR-34a was processed to target miR-34a-5p in human osteosarcoma and lung cancer cells, as determined by selective stem-loop reverse transcription quantitative polymerase chain reaction analysis. The mitochondrial inner membrane protein MPV17 like 2 (MPV17L2) was validated as a direct target for miR-34a-5p by dual luciferase reporter assay. Western blot analysis revealed that bioengineered miR-34a-5p effectively reduced MPV17L2 protein outcomes, leading to much lower levels of respiratory chain Complex I activities and intracellular ATP that were determined with specific assay kits. Moreover, Seahorse Mito Stress Test assay was conducted, and the results showed that biologic miR-34a-5p sharply reduced cancer cell mitochondrial respiration capacity, accompanied by a remarkable increase of oxidative stress and elevated apoptotic cell death, which are manifested by greater levels of reactive oxygen species and selective apoptosis biomarkers, respectively. These results demonstrate the presence and involvement of the miR-34a-5p-MPV17L2 pathway in the control of mitochondrial functions in human carcinoma cells and support the utility of novel bioengineered miRNA molecules for functional studies.

3.
Colloids Surf B Biointerfaces ; 216: 112528, 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35525229

RESUMO

Macrophages polarization in bone immune microenvironment is crucial in bone regeneration. In this work, mineralized collagen (MC) coatings with photo-thermal effect were prepared through incorporation of polydopamine (PDA). MC coatings with different thicknesses were deposited on titanium substrate through electrochemical deposition. PDA preformed on the substrate, acting as a photo-thermal agent. The effects of light illumination, i.e., different thermal effects, on the polarization of mouse bone marrow-derived macrophages were explored. It was found that heat can promote the M1 polarization of macrophages and inhibit the M2 polarization. Also, gene expression results revealed that such photo illumination based macrophage modulation is effective and safe. It provides a possible way for the design of functional materials to regulate the bone immune microenvironment.

4.
Cancer Discov ; : OF1-OF12, 2022 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-35543554

RESUMO

The efficacy and potential limitations of molecular residual disease (MRD) detection urgently need to be fully elucidated in a larger population of non-small cell lung cancer (NSCLC). We enrolled 261 patients with stages I to III NSCLC who underwent definitive surgery, and 913 peripheral blood samples were successfully detected by MRD assay. Within the population, only six patients (3.2%) with longitudinal undetectable MRD recurred, resulting in a negative predictive value of 96.8%. Longitudinal undetectable MRD may define the patients who were cured. The peak risk of developing detectable MRD was approximately 18 months after landmark detection. Correspondingly, the positive predictive value of longitudinal detectable MRD was 89.1%, with a median lead time of 3.4 months. However, brain-only recurrence was less commonly detected by MRD (n = 1/5, 20%). Further subgroup analyses revealed that patients with undetectable MRD might not benefit from adjuvant therapy. Together, these results expound the value of MRD in NSCLC. SIGNIFICANCE: This study confirms the prognostic value of MRD detection in patients with NSCLC after definitive surgery, especially in those with longitudinal undetectable MRD, which might represent the potentially cured population regardless of stage and adjuvant therapy. Moreover, the risk of developing detectable MRD decreased stepwise after 18 months since landmark detection.

6.
J Cardiothorac Surg ; 17(1): 115, 2022 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-35551621

RESUMO

BACKGROUND: Post-thymectomy myasthenia gravis (PTMG) is defined as thymoma patients without signs of myasthenia gravis (MG) pre-operation, but develop MG after radical surgical resection. PTMG might be misdiagnosed not only because of its rare incidence, but also the uncertain interval between the removal of thymoma and the new onset MG. Additionally, some surgeons and anesthesiologists pay less attention to those asymptomatic thymoma patients in perioperative management, leading to the neglect of new onset PTMG, and miss the best time to treat it. CASE PRESENTATION: Majority of cases of PTMG with onset at stage I-II on the basis of Myasthenia Gravis Foundation of America (MGFA) classification have been reported, but rarely at stage V, which requiring intubation or non-invasive ventilation to avoid intubation. Herein, we presented a 70-year-old male with PTMG onset at MGFA stage V, meanwhile, he had severe pulmonary infection interfering with the diagnosis of PTMG, and eventually progressed to refractory PTMG, which requiring much more expensive treatments and longer hospital stays. CONCLUSION: In the perioperative management of asymptomatic thymoma patients, careful preoperative evaluation including physical examination, electrophysiological test and acetylcholine receptor antibodies (AChR-Ab) level should be done to identify subclinical MG. Complete resection should be performed during thymectomy, if not, additional postoperative adjuvant therapy is neccessary to avoid recurrence. It's important to identify PTMG at a early stage, especially when being interfered with by postoperative complications, such as lung infection, so that treatments could be initiated as soon as possible to avoid developing to refractory PTMG.

7.
FASEB J ; 36 Suppl 12022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35556790

RESUMO

MicroRNAs (miRNA or miR) are small noncoding RNAs derived from the genome to control posttranscriptional gene expression critical for various cellular processes. Recently we have invented a novel platform technology that offers high-yield production of humanized, bioengineered miRNA agents (hBERAs) for research and development. This study is aimed to produce and utilize a novel biologic miR-34a-5p (or miR-34a) molecule, namely hBERA/miR-34a, to delineate the role of miR-34a-5p in the regulation of mitochondrial functions in carcinoma cells. Bioengineered hBERA/miR-34a was selectively processed to target miR-34a-5p in human osteosarcoma and lung cancer cells. The mitochondrial inner membrane protein MPV17 like 2 (MPV17L2) was identified and validated as a new direct target for miR-34a-5p. Furthermore, we demonstrated that miR-34a-5p-controlled MPV17L2 protein downregulation significantly inhibited respiratory chain complex I assembly and activities as well as intracellular ATP levels. Consequently, biologic miR-34a-5p treatment sharply reduced cancer cell mitochondrial respiration, increased oxidative stress, and elevated apoptotic cell death. These results demonstrate an important role of miR-34a-5p-MPV17L2 pathway in the control of mitochondrial functions in carcinoma cells and support the utility of novel bioengineered miRNA molecules for functional studies.

8.
Artigo em Inglês | MEDLINE | ID: mdl-35575231

RESUMO

Brown adipose tissue (BAT) is the primary site of adaptive thermogenesis, which is involved in energy expenditure and has received much attention in the field of obesity treatment. By screening a small-molecular library of Food and Drug Administration approved drugs, pantothenic acid was identified as being able to significantly upregulate the expression of uncoupling protein 1 (UCP1), a key thermogenic protein found in BAT. Pantothenate (PA) treatment decreased adiposity, reversed fatty liver and improved glucose homeostasis via increased energy expenditure in C57BL/6J mice fed a high-fat diet. PA could also increase BAT activity and induce beige formation. Mechanistically, the beneficial effects were evidently mediated by UCP1, because PA treatment was unable to ameliorate the obesity in UCP1 knockout mice. In conclusion, we identified PA as a safe and effective BAT activator that can reduce obesity and may represent a promising strategy for the clinical treatment of obesity and related metabolic diseases.

9.
Eur Radiol ; 2022 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-35567605

RESUMO

OBJECTIVES: We aimed to evaluate myocardial fibrosis using cardiac magnetic resonance (CMR) T1 mapping in type 2 diabetes mellitus (T2DM) patients and investigate the association between left ventricular (LV) subclinical myocardial dysfunction and myocardial fibrosis. METHODS: The study included 37 short-term (≤ 5 years) and 44 longer-term (> 5 years) T2DM patients and 41 healthy controls. The LV global strain parameters and T1 mapping parameters were compared between the abovementioned three groups. The association of T1 mapping parameters with diabetes duration, in addition to other risk factors, was determined using multivariate linear regression analysis. The correlation between LV strain parameters and T1 mapping parameters was evaluated using Pearson's correlation. RESULTS: The peak diastolic strain rates (PDSRs) were significantly lower in longer-term T2DM patients compared to those in healthy subjects and short-term T2DM patients (p < 0.05). The longitudinal peak systolic strain rate and peak strain were significantly lower in the longer-term T2DM compared with the short-term T2DM group (p < 0.05). The extracellular volumes (ECVs) were higher in both subgroups of T2DM patients compared with control subjects (all p < 0.05). Multivariate linear regression analysis showed that diabetes duration was independently associated with ECV (ß = 0.413, p < 0.001) by taking covariates into account. Pearson's analysis showed that ECV was associated with longitudinal PDSR (r = - 0.441, p < 0.001). CONCLUSION: T1 mapping could detect abnormal myocardial fibrosis early in patients with T2DM, which can cause a decline in the LV diastolic function. KEY POINTS: • CMR T1 mapping could detect abnormal myocardial fibrosis early in patients with T2DM. • The diabetes duration was independently associated with ECV. • Myocardial fibrosis can cause a decline in the LV diastolic function in T2DM patients.

11.
Light Sci Appl ; 11(1): 112, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35478191

RESUMO

Near-infrared (NIR)-emitting phosphor-converted light-emitting diodes have attracted widespread attention in various applications based on NIR spectroscopy. Except for typical Cr3+-activated NIR-emitting phosphors, next-generation Cr3+-free NIR-emitting phosphors with high efficiency and tunable optical properties are highly desired to enrich the types of NIR luminescent materials for different application fields. Here, we report the Fe3+-activated Sr2-yCay(InSb)1-zSn2zO6 phosphors that exhibit unprecedented long-wavelength NIR emission. The overall emission tuning from 885 to 1005 nm with broadened full-width at half maximum from 108 to 146 nm was realized through a crystallographic site engineering strategy. The NIR emission was significantly enhanced after complete Ca2+ incorporation owing to the substitution-induced lower symmetry of the Fe3+ sites. The Ca2InSbO6:Fe3+ phosphor peaking at 935 nm showed an ultra-high internal quantum efficiency of 87%. The as-synthesized emission-tunable phosphors demonstrated great potential for NIR spectroscopy detection. This work initiates the development of efficient Fe3+-activated broadband NIR-emitting phosphors and opens up a new avenue for designing NIR-emitting phosphor materials.

12.
Front Physiol ; 13: 865442, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35464080

RESUMO

In insects, metamorphosis is controlled by juvenile hormone (JH) and 20-hydroxyecdysone (20E). Krüppel homolog 1 (Kr-h1), a key JH-early inducible gene, is responsible for the suppression of metamorphosis and the regulation of the Broad-Complex (Br-C) gene, which is induced by 20E and functions as a "pupal specifier". In this study, we identified and characterized the expression patterns and tissue distribution of DaKr-h1 and DaBr-C at various developmental stages of Dendroctonus armandi. The expression of the two genes was induced by JH analog (JHA) methoprene and 20E, and their functions were investigated by RNA interference. DaKr-h1 and DaBr-C were predominantly expressed in the heads of larvae and were significantly downregulated during the molting stage. In contrast, the DaKr-h1 transcript level was highest in the adult anterior midgut. DaBr-C was mainly expressed in female adults, with the highest transcript levels in the ovaries. In the larval and pupal stages, both JHA and 20E significantly induced DaKr-h1, but only 20E significantly induced DaBr-C, indicating the importance of hormones in metamorphosis. DaKr-h1 knockdown in larvae upregulated DaBr-C expression, resulting in precocious metamorphosis from larvae to pupae and the formation of miniature pupae. DaKr-h1 knockdown in pupae suppressed DaBr-C expression, increased emergence, caused abnormal morphology, and caused the formation of small-winged adults. These results suggest that DaKr-h1 is required for the metamorphosis of D. armandi. Our findings provide insight into the roles of DaKr-h1 and DaBr-C in JH-induced transcriptional repression and highlight DaKr-h1 as a potential target for metamorphosis suppression in D. armandi.

13.
Inorg Chem ; 61(15): 5903-5911, 2022 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-35380804

RESUMO

Multicolor-emission-based single-phase white light derived from different luminescence centers is an effective way to manipulate the optical properties of halide perovskites. In this work, we developed a codoping strategy to incorporate Bi3+ and Te4+ emission centers into all-inorganic lead-free Cs2HfCl6 perovskite by a hydrothermal method. The as-prepared Bi3+/Te4+-doped Cs2HfCl6 microcrystals show bright blue (Bi3+), yellow (Te4+), and warm-white emissions (Bi3+/Te4+), respectively. The broad efficient dual emission in Bi3+/Te4+ co-doped Cs2HfCl6 is assigned to the typical 3P1 → 1S0 transition emission from Bi3+ originating from [BiHf + VCl] and self-trapped excitons (STEs) from Te4+. Moreover, the concentration-optimized Cs2HfCl6:Te4+ shows excellent antiwater stability and high photoluminescence quantum yield (PLQY) of ∼70%. Meanwhile, a white light-emitting diode (WLED) fabricated using Bi3+/Te4+ co-doped Cs2HfCl6 is close to warm white with a color rendering index (CRI) of 75.4, CIE color coordinate of (0.370, 0.393), and a correlated color temperature (CCT) of 4380 K. These results suggest that Bi3+/Te4+ co-doped all-inorganic lead-free Cs2HfCl6 is a potential single-phase white light-emitting phosphor candidate for solid-state lightings.

14.
Transbound Emerg Dis ; 2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35403352

RESUMO

Bluetongue virus (BTV), a member of the genus Orbivirus in the family Reoviridae, is transmitted by biting midges and causes severe disease in domestic and wild ruminants. In the present study, a BTV strain, BTV-20/GX015/China/2013 (GX015), was isolated from sentinel cattle in Guangxi, China. Virus neutralization tests and phylogenetic analyses based on genomic segments 2 (S2) and 6 (S6) indicated that GX015 belongs to BTV serotype 20 (BTV-20) and represents a new topotype within BTV-20 strains, which makes GX015 the first BTV-20 strain isolated in China. Genomic analyses suggested that the 10 genomic segments of GX015 originated from a reassortment event, in which S2 and S6 are derived from exotic BTV-20 strains (South Africa or Australia), whereas the remaining eight genomic segments are apparently of Chinese origin and most likely share the same ancestor with a Taiwanese BTV-12 strain. Importantly, we evaluated the infectivity and pathogenicity of the BTV-20 strain in mice lacking the interferon receptor (IFNAR-/- mice, a good animal model for studying the pathogenesis, virulence and transmission of BTVs) and sheep for the first time, and found that GX015 causes severe disease and death in IFNAR-/- mice and clinical signs and viraemia in the natural host sheep. These results improve our understanding of the genetic characteristics, diversity and pathogenicity of BTVs, which is important for developing diagnostic methods and vaccines for the surveillance and prevention of bluetongue disease.

15.
Polymers (Basel) ; 14(7)2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35406286

RESUMO

Polarizer is a key component of the liquid crystal display panel, and the optical properties mainly include transmittance, degree of polarization and chromaticity. Polarizer is made of a multilayer optical film, in which the PVA polarizing film is the core structure for realizing the polarization of the whole polarizer. PVA polarizing film is commonly manufactured through a multi-step craft, including rinsing, dyeing, stretching and correcting. The correction process has a significant impact on the final apparent color and optical properties of the polarizer. In this study, the KI concentration in the correcting tank, ranging from 1% to 3%, was systematically investigated. With the increase in KI concentration, the Raman vibration peak at 160 cm-1 representing I5- ions gradually weakened, while the Raman vibration peak at 110 cm-1 representing I3- ions gradually increased, indicating that the KI in the correcting tank changed the chemical equilibrium of polyiodide ions in PVA. Then abundant chromophore I5- ions were consumed and I3- ions generated, so that the apparent color of PVA polarizing film gradually changed from dark blue to dark gray, and the chromaticity a-value and b-value gradually increased. The change in the concentration of dichroic species (I5- and I3-) in PVA polarizing film had directly affected its transmittance in the visible range. From the UV-Vis transmittance spectrum of PVA polarizing film, when the I5- ions were consumed and I3- ions generated, the transmittance of PVA polarizing film in the region of 675-525 nm wavelength increased gradually while the polarization degree also increased.

16.
RSC Adv ; 12(4): 2425-2435, 2022 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-35425220

RESUMO

The development of non-noble metal catalysts with high-performance, long stability and low-cost is of great importance for fuel cells, to promote the oxygen reduction reaction (ORR). Herein, Fe/Co/N-C/graphene composites were easily prepared by using Fe/ZIF-67 loaded on graphene oxide (GO). The Fe/Co/porous carbon nanoparticles were uniformly dispersed on graphene with high specific surface area and large porosity, which endow high nitrogen doping and many more active sites with better ORR performance than the commercial 20 wt% Pt/C. Therefore, Fe/Co/N-C/graphene composites exhibited excellent ORR activity in alkaline media, with higher initial potential (0.91 V) and four electron process. They also showed remarkable long-term catalytic stability with 96.5% current retention after 12 000 s, and outstanding methanol resistance, compared with that of 20 wt% Pt/C catalysts. This work provides an effective strategy for the preparation of non-noble metal-based catalysts, which could have significant potential applications, such as in lithium-air batteries and water-splitting devices.

17.
J Int Med Res ; 50(4): 3000605221096161, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35485877

RESUMO

Waldenstrom's macroglobulinemia (WM) is a rare type of malignant B-cell lymphoma. The main feature of WM is elevated serum monoclonal immunoglobulin M, similar to multiple myeloma (MM). Unlike in MM, the rarity of destructive bone lesions in WM has been repeatedly emphasized. We report a unique case of WM with a vertebral compression fracture as the first symptom. This case highlights that the presence or absence of bone destruction may not clearly distinguish between WM and MM. The possibility of WM should be considered in patients with vertebral fracture and destruction as the first presentation. Performing vertebral bone marrow aspiration biopsy during percutaneous vertebroplasty is a convenient and effective method to assist in the diagnosis of WM.


Assuntos
Fraturas por Compressão , Linfoma de Células B , Mieloma Múltiplo , Fraturas da Coluna Vertebral , Macroglobulinemia de Waldenstrom , Humanos , Imunoglobulina M , Mieloma Múltiplo/complicações , Mieloma Múltiplo/diagnóstico , Fraturas da Coluna Vertebral/complicações , Fraturas da Coluna Vertebral/diagnóstico por imagem , Macroglobulinemia de Waldenstrom/complicações , Macroglobulinemia de Waldenstrom/diagnóstico , Macroglobulinemia de Waldenstrom/patologia
18.
J Orthop Translat ; 33: 24-30, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35228994

RESUMO

BACKGROUND: Currently dual-energy X-ray absorptiometry (DXA) and phantom-based quantitative computed tomography (PB-QCT) have been utilized to diagnose osteoporosis widely in clinical practice. While traditional phantom-less QCT (PL-QCT) is limited by the precision of manual calibration using body tissues, such as fat and muscle. OBJECTIVE: The aim of this study is to validate the accuracy and precision of one newly-developed automatic PL-QCT system to measure spinal bone mineral density (BMD) and diagnose osteoporosis. METHODS: A total of 36 patients were enrolled for comparison of BMD measurement between DXA and QCT. CT images of 63 patients were analyzed by both PB-QCT and newly developed automatic PL-QCT system, then the BMD results generated by the automatic PL-QCT were utilized to diagnose osteoporosis. The diagnostic outcomes were compared with that of DXA and PB-QCT to assess the performance of the new system. RESULTS: BMD test results showed that the automatic PL-QCT system had higher precision than previous studies performed with QCT, while maintaining similar capability to diagnose osteoporosis as DXA and PB-QCT. Area under curve (AUC) result of PL-QCT was larger than 0.8 for predicting spine DXA T-score in receiver operating characteristic (ROC) analysis. Pearson correlation analysis (r â€‹= â€‹0.99) showed strong linear correlation and Bland-Altman analysis (bias â€‹= â€‹3.0mg/cc) indicated little difference between the two methods. The precision result (CV â€‹= â€‹0.89%) represented good reproducibility of the new system. CONCLUSION: The traditional PL-QCT system has relatively low reproducibility due to the manual selection of the region of interest (ROI) of body tissues. Automatic selection of ROI in this new system makes the BMD testing more convenient and improves precision significantly. Compared with traditional BMD measurement methods, the automatic PL-QCT system had higher precision in accurate diagnosis of osteoporosis with great potential in translational research and wide clinical application. TRANSLATIONAL POTENTIAL STATEMENT: With high accuracy and precision, the automatic PL-QCT system could serve as an opportunistic screening tool for osteoporosis patients in the future. It could also facilitate related researches by providing more reliable data collection, both retrospectively and longitudinally.

19.
Exp Mol Med ; 54(3): 334-345, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35354913

RESUMO

Rheumatoid arthritis (RA) is an autoimmune disease characterized by infiltration of immune cells in the synovium. However, the crosstalk of immune cells and synovial fibroblasts is still largely unknown. Here, global miRNA screening in plasma exosomes was carried out with a custom microarray (RA patients vs. healthy controls = 9:9). A total of 14 exosomal miRNAs were abnormally expressed in the RA patients. Then, downregulated expression of exosomal miR-204-5p was confirmed in both the replication (RA patients vs. healthy controls = 30:30) and validation groups (RA patients vs. healthy controls = 56:60). Similar to the findings obtained in humans, a decreased abundance of exosomal miR-204-5p was observed in mice with collagen-induced arthritis (CIA). Furthermore, Spearman correlation analysis indicated that plasma exosomal miR-204-5p expression was inversely correlated with disease parameters of RA patients, such as rheumatoid factor, erythrocyte sedimentation rate, and C-reactive protein. In vitro, our data showed that human T lymphocytes released exosomes containing large amounts of miR-204-5p, which can be transferred into synovial fibroblasts, inhibiting cell proliferation. Overexpression of miR-204-5p in synovial fibroblasts suppressed synovial fibroblast activation by targeting genes related to cell proliferation and invasion. In vivo assays found that administration of lentiviruses expressing miR-204-5p markedly alleviated the disease progression of the mice with CIA. Collectively, this study identified a novel RA-associated plasma exosomal miRNA-204-5p that mediates the communication between immune cells and synovial fibroblasts and can be used as a potential biomarker for RA diagnosis and treatment.


Assuntos
Artrite Experimental , Artrite Reumatoide , Exossomos , MicroRNAs , Animais , Artrite Experimental/genética , Artrite Reumatoide/genética , Proliferação de Células/genética , Exossomos/genética , Fibroblastos/metabolismo , Humanos , Camundongos , MicroRNAs/genética , Membrana Sinovial/metabolismo
20.
Polymers (Basel) ; 14(6)2022 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-35335536

RESUMO

In this work, a small amount of carbon nanotubes (CNTs) was used to partially replace the silica in ethylene-propylene-diene monomer (EPDM) to prepare EPDM composites via mechanical blending. The mechanical properties, thermal-oxidative aging properties and thermal stability of the composites were systematically investigated. The results showed that with the increase of CNTs content, the Shore A hardness and stress at 100% strain of the composites increased, while the elongation at break decreased. With the aging time increasing, the aging coefficient and elongation at break of composites decreased while hardness increased due to the raise of crosslinking density. In addition, evidences were found to demonstrate the improved aging resistance by adding CNTs in the EPDM composites, including the less change in Shore A hardness, the smaller change ratio of elongation at break and the lower aging coefficient. When the content of CNTs reached 10 phr, the aging coefficient of the EPDM composite aged for 168 h was nearly twice that of the composite without CNTs, and the thermal stability of the EPDM composite with CNTs was improved as demonstrated by thermal analysis.

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