Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 318
Filtrar
Filtros adicionais











País/Região como assunto
Intervalo de ano
1.
J Nanosci Nanotechnol ; 20(2): 1140-1147, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383114

RESUMO

The fabrication of bimetallic catalysts has been taken great focus in the concept of heterogeneous catalysis due to their high efficiency and economic concerns. In this work, a series of bimetallic Ru-Re catalysts were designed and synthesized for the selective hydrogenation of dimethyl terephthalate (DMT) to 1,4-cyclohexane dicarboxylate (DMCD) under mild condition. Characterization techniques including the XRD, TEM, STEM-HAADF EDX elemental mapping, H2-TPR, and XPS were used to study the surface chemical property, the morphology, as well as the catalytic behavior of different samples. It was revealed that the monometallic Ru catalyst already has the capacity to activate and transform DMT into DMCD. Whilst the promotion effect can be optimized to a maximum with only small amount of Re, with the mass ratio of Ru/Re as 10:1. It was also revealed that the addition of Re could largely enhance the distribution of surface active metal species, facilitate the charge transfer between Ru and Re, as well as strengthen the Ru-Re synergistic interaction, which further led to the modification of the redox ability and the catalytic performances of samples. However, excessive addition of Re caused strong interaction between Ru and Re, and further limited the H2 activation and the seasonable release of the active reducible metal species, which was responsible for the depressed catalytic performances in the presence of higher Re loading. The Ru1.25Re0.13/AC catalyst displayed the DMT conversion of 82% with DMCD selectivity of 96% under mild condition of 70 °C at 3 MPa. The specific rate of Ru1.25Re0.13/AC based on per gram of Ru was 0.44 mol·g-1 Ru·h-1.

2.
J Nanosci Nanotechnol ; 20(2): 1215-1223, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383121

RESUMO

Designing a highly active, stable and cost-effective electrocatalyst with multiple functionalities toward hydrogen evolution and oxygen reduction applications is crucial for the development of renewable energy sources. Here, the synthesis of hollow PtNi nanostrings via a facile two-step template method is reported. The PtNi nanostrings own Pt-rich rough surfaces, and hollow string-like structure with the structural disorder morphology. Impressively, the unique hollow PtNi nanostrings exhibit excellent electrocatalytic activity toward the hydrogen evolution and oxygen reduction reactions. The obtained overpotential is only 44.60 mV at current density of 10 mA cm-2 for hydrogen evolution reaction. Furthermore, the hollow PtNi nanostrings exhibit a high mass activity of 2.5 A mg-1Pt and a superior specific activity of 3.89 mA cm-2 at 0.90 V versus reversible hydrogen electrode in oxygen reduction reaction, respectively, which are 10 and 9 times higher than those of the commercial Pt/C. This work provides a promising approach for the synthesis of highly bifunctional electrocatalysts with a hollow sting-like structure to promote their application in the hydrogen evolution and oxygen reduction reactions.

3.
Artigo em Inglês | MEDLINE | ID: mdl-31484371

RESUMO

A novel graphite-phase carbon nitride (g-C3N4)/bismuth ferrite (BiFeO3)/carbon nanotubes (CNTs) ternary magnetic composite (CNBT) was prepared by a hydrothermal synthesis. Using this material, Cr(VI) and methylene blue (MB) were removed from wastewater through synergistic adsorption and photocatalysis. The effects of pH, time, and pollutant concentration on the photocatalytic performance of CNBT, as well as possible interactions between Cr(VI) and MB species were analyzed. The obtained results showed that CNTs could effectively reduce the recombination rate of electron-hole pairs during the photocatalytic reaction of the g-C3N4/BiFeO3 composite, thereby improving its photocatalytic performance, while the presence of MB increased the reduction rate of Cr(VI). After 5 h of the simultaneous adsorption and photocatalysis by CNBT, the removal rates of Cr(VI) and MB were 93% and 98%, respectively. This study provides a new theoretical basis and technical guidance for the combined application of photocatalysis and adsorption in the treatment of wastewaters containing mixed pollutants.

4.
J Vis Exp ; (150)2019 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-31475992

RESUMO

We herein present a method for the synthesis of HNbWO6, HNbMoO6, HTaWO6 solid acid nanosheet modified Pt/CNTs. By varying the weight of various solid acid nanosheets, a series of Pt/xHMNO6/CNTs with different solid acid compositions (x = 5, 20 wt%; M = Nb, Ta; N = Mo, W) have been prepared by carbon nanotube pretreatment, protonic exchange, solid acid exfoliation, aggregation and finally Pt particles impregnation. The Pt/xHMNO6/CNTs are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and NH3-temperature programmed desorption. The study revealed that HNbWO6 nanosheets were attached on CNTs, with some edges of the nanosheets being bent in shape. The acid strength of the supported Pt catalysts increases in the following order: Pt/CNTs < Pt/5HNbWO6/CNTs < Pt/20HNbMoO6/CNTs < Pt/20HNbWO6/CNTs < Pt/20HTaWO6/CNTs. In addition, the catalytic hydroconversion of lignin-derived model compound: diphenyl ether using the synthesized Pt/20HNbWO6 catalyst has been investigated.

5.
Appl Opt ; 58(26): 7121-7126, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31503983

RESUMO

This work explores the variable curvature mirror's (VCM) elastic bending rules through modeling it as a thin elastic plate with an exponential thickness distribution actuated with a uniform pressure under simply supported boundary conditions. By using the small-parameter method, the general analytical expression of a plate's deflection is worked out. The results calculated by the analytical solution are compared to the finite element analysis of a VCM model with the same specific parameters. We demonstrate that the two have a good correlation with the each other. This analytical solution is an effective way to predict a VCM's deflection.

6.
Cell Biol Int ; 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31393045

RESUMO

Cardamonin (CD), a naturally occurring chalcone isolated from large black cardamom, was previously reported to suppress the proliferation of breast cancer cells. However, its precise molecular anti-tumor mechanisms have not been well elucidated. In this study, we found that CD markedly inhibited the proliferation of MDA-MB 231 and MCF-7 breast cancer cells through the induction of G2/M arrest and apoptosis. Reactive oxygen species (ROS) plays a pivotal role in the inhibition of CD-induced cell proliferation. Treatment with N-acetyl-cysteine (NAC), an ROS scavenger, blocked CD-induced G2/M arrest and apoptosis in this study. Quenching of ROS by overexpression of catalase also blocked CD-induced cell cycle arrest and apoptosis. We showed that CD enhanced the expression and nuclear translocation of Forkhead box O3 (FOXO3a) via upstream c-Jun N-terminal kinase, inducing the expression of FOXO3a and its target genes, including p21, p27, and Bim. This process led to the reduction of cyclin D1 and enhancement of activated caspase-3 expression. The addition of NAC markedly reversed these effects, knockdown of FOXO3a using small interfering RNA also decreased CD-induced G2/M arrest and apoptosis. In vivo, CD efficiently suppressed the growth of MDA-MB 231 breast cancer xenograft tumors. Taken together, our data provide a molecular mechanistic rationale for CD-induced cell cycle arrest and apoptosis in breast cancer cells.

7.
BMC Bioinformatics ; 20(1): 397, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31315562

RESUMO

BACKGROUND: Tandem mass spectrometry (MS/MS)-based database searching is a widely acknowledged and widely used method for peptide identification in shotgun proteomics. However, due to the rapid growth of spectra data produced by advanced mass spectrometry and the greatly increased number of modified and digested peptides identified in recent years, the current methods for peptide database searching cannot rapidly and thoroughly process large MS/MS spectra datasets. A breakthrough in efficient database search algorithms is crucial for peptide identification in computational proteomics. RESULTS: This paper presents MCtandem, an efficient tool for large-scale peptide identification on Intel Many Integrated Core (MIC) architecture. To support big data processing capability, a novel parallel match scoring algorithm, named MIC-SDP (spectrum dot product), and its two-level parallelization are presented in MCtandem's design. In addition, a series of optimization strategies on both the host CPU side and the MIC side, which includes pre-fetching, optimized communication overlapping scheme, multithreading and hyper-threading, are exploited to improve the execution performance. CONCLUSIONS: For fair comparisons, we first set up experiments and verified the 28 fold times speedup on a single MIC against the original CPU-based implementation. We then execute the MCtandem for a very large dataset on an MIC cluster (a component of the Tianhe-2 supercomputer) and achieved much higher scalability than in a benchmark MapReduce-based programs, MR-Tandem. MCtandem is an open-source software tool implemented in C++. The source code and the parameter settings are available at https://github.com/LogicZY/MCtandem .

8.
Int J Med Sci ; 16(6): 793-799, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31337952

RESUMO

Background: Essential hypertension (EH) is a chronic disease of universal high prevalence and a well-established independent risk factor for cardiovascular and cerebrovascular events. The regulation of blood pressure is crucial for improving life quality and prognoses in patients with EH. Therefore, it is of important clinical significance to develop prediction models to recognize individuals with high risk for EH. Methods: In total, 965 subjects were recruited. Clinical parameters and genetic information, namely EH related SNPs were collected for each individual. Traditional statistic methods such as t-test, chi-square test and multi-variable logistic regression were applied to analyze baseline information. A machine learning method, mainly support vector machine (SVM), was adopted for the development of the present prediction models for EH. Results: Two models were constructed for prediction of systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively. The model for SBP consists of 6 environmental factors (age, BMI, waist circumference, exercise [times per week], parental history of hypertension [either or both]) and 1 SNP (rs7305099); model for DBP consists of 6 environmental factors (weight, drinking, exercise [times per week], TG, parental history of hypertension [either and both]) and 3 SNPs (rs5193, rs7305099, rs3889728). AUC are 0.673 and 0.817 for SBP and DBP model, respectively. Conclusions: The present study identified environmental and genetic risk factors for EH in northern Han Chinese population and constructed prediction models for SBP and DBP.

9.
DNA Cell Biol ; 38(8): 796-807, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31295012

RESUMO

Myocardial hypertrophy is an important cause of heart failure and sudden death. Studies have shown that Mitofusin-2 (MFN2) is downregulated in myocardial hypertrophy, but the upstream regulation mechanism underlying its downexpression in cardiomyocytes is still unclear. This study aims to identify the expression profile of microRNAs (miRNAs) in hypertrophic cardiomyopathy (HCM) and explore the function of miRNA-20 in inducing cardiomyocyte hypertrophy through regulating MFN2. Through miRNA + mRNA microarray analysis, 1451 miRNAs were identified, 367 miRNAs expressed differently between groups. Meanwhile, a number of 24,718 mRNAs were identified, among which 5850 mRNAs were upregulated and 3005 mRNAs were downregulated in HCM group compared with the control group. Expression of hsa-miRNA-20a-5p was 2.26 times higher in the HCM group compared with the control group and 7 target gene prediction programs predicted MFN2 as a target of miRNA-20. In vitro model of hypertrophic cardiomyocytes displayed high expression level of miRNA-20, atrial natriuretic peptide (ANP) mRNA, and protein, accompanying low expression level of Mfn2 mRNA and protein, which meant miRNA-20 played a role in cardiomyocyte hypertrophy and might interact with MFN2 to function. Thereafter, overexpression of miRNA-20 led to cell hypertrophy accompanied with lowly expressed Mfn2 mRNA and protein. When transfected with miRNA-20 inhibitors, the expression of miRNA-20 and ANP gene was attenuated and MFN2 was the other way around. The cell surface area of Ang II group and mimic group was significantly larger compared with the control group, and in the inhibitor+Ang II group, the area was significantly decreased compared with the Ang II group. Dual-luciferase assays showed that miRNA-20 bound to 3' untranslated region of MFN2 and inhibited its expression. In conclusion, hypertrophic myocardium and normal myocardium have different miRNA expression profiles and the effect of miRNA-20 reducing the expression of MFN2 plays a role in promoting cardiomyocyte hypertrophy.


Assuntos
Cardiomiopatia Hipertrófica/genética , GTP Fosfo-Hidrolases/genética , MicroRNAs/genética , Proteínas Mitocondriais/genética , Miócitos Cardíacos/patologia , Regiões 3' não Traduzidas , Adulto , Angiotensina II/farmacologia , Animais , Estudos de Casos e Controles , Feminino , Regulação da Expressão Gênica , Humanos , Masculino , Proteínas de Membrana/genética , MicroRNAs/metabolismo , Pessoa de Meia-Idade , Miócitos Cardíacos/efeitos dos fármacos , Ratos Wistar
10.
Fitoterapia ; 137: 104262, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31284018

RESUMO

Eight undescribed 9,19-cycloartane type triterpenoid glycosides (cimdalglnoside A-H) and ten known analogues were obtained from the phytochemical research on the roots of Actaea dahurica (syn. Cimicifuga dahurica). All compounds were characterised by spectroscopic experiments, and chemical method. All the compounds isolated were assayed for cytotoxicity to five human cancer cell lines. Cimdalglnoside G showed promising cytotoxicities against Hela, and MCF-7 cell lines with IC50 values at 7.7 and 12.2 µM.

11.
Chem Commun (Camb) ; 55(53): 7663-7666, 2019 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-31198925

RESUMO

A controlled, weakly basic Co/CeOx catalyst was designed for one-pot conversion of cellulose to ethylene glycol (EG) and 1,2-propylene glycol (1,2-PG) to achieve near-equivalent yield. The efficiency is mainly attributed to Con+-Ox-Ce3+ base-acid pairs that hindered humin formation by ensuring a precise balance across the various steps of the reaction.

12.
Fitoterapia ; 137: 104185, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31150768

RESUMO

Six new and one known dihydroagarofuran sesquiterpenoids esterified with organic acids were obtained from the leaves of Tripterygium wilfordii. Spectroscopic techniques (UV, IR, MS, NMR, ORD and CD) were used for the structure elucidation of the compounds. The structures of compounds 1 and 2 were confirmed by X-ray single crystallographic analyses. The inhibitory effects on NO production in LPS-induced macrophages of 1-7 were conducted. At 10 µmol/L, compounds 1, 2 and 7 showed moderate inhibitory effects on NO production in LPS-induced macrophages with inhibitory rate at 31.2 ±â€¯3.6, 40.9 ±â€¯4.3, and 66.79 ±â€¯3.1%, respectively.


Assuntos
Macrófagos/efeitos dos fármacos , Sesquiterpenos/farmacologia , Tripterygium/química , Animais , Camundongos , Estrutura Molecular , Óxido Nítrico/metabolismo , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Folhas de Planta/química , Células RAW 264.7 , Sesquiterpenos/isolamento & purificação
13.
Plant Physiol Biochem ; 141: 164-171, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31170640

RESUMO

For a comprehensive understanding of gene expression, enzyme activity and sugar concentrations in response to short-term water deficit in apple (Greensleeves), sugar-modulated gene expression and enzyme activities were analyzed. Water stress resulted in the accumulation of sorbitol, glucose, fructose, galactose and starch, accompanied by a significant reduction in photosynthesis and sucrose concentration. In response to short-term water deficits, the activities of aldose-6-phosphate reductase (A6PR; EC 1.1.1.200), sorbitol dehydrogenase (SDH; EC 1.1.1.14), neutral invertase (NINV; EC 3.2.1.26), sucrose synthase (SUSY; EC 2.4.1.13), and fructokinase (FK; EC 2.7.1.4) were higher, whereas cell wall invertase (CWINV; EC 3.2.1.26) and hexokinase (HK; EC 2.7.1.1) activities were lower. In addition, sucrose phosphate synthase (SPS; EC 2.4.1.14) activity increased during the initial stages of dehydration and then decreased as the drought strengthened. Transcript levels of MdA6PR, MdSDH1/2, MdNINV1/2, MdSUSY3, MdFK1/2/4, MdSOT1/2, MdSUC1-3, MdTMT2/3, MdvGT1, MdpGlcT1-4 were upregulated, whereas transcript levels of MdCWINV1/2, MdHK1/2/3/5, and MdTMT1 were downregulated after 6 days of water stress. These findings suggest that the sorbitol metabolism pathway is induced and high levels of hexose derived from photosynthetic products are transported into vacuoles for adjustment to the water deficit. Our results provide insights into the relationships between sugar levels and sugar-modulated gene and enzyme activity in response to the imposition of short-term water stress.


Assuntos
Metabolismo dos Carboidratos/genética , Secas , Regulação da Expressão Gênica de Plantas , Malus/fisiologia , Folhas de Planta/fisiologia , Parede Celular/metabolismo , Frutas/metabolismo , Glucosiltransferases/metabolismo , Malus/genética , Fotossíntese , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Sorbitol/metabolismo , Estresse Fisiológico , Sacarose/metabolismo , beta-Frutofuranosidase/metabolismo
14.
Int J Nanomedicine ; 14: 4277-4292, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31239679

RESUMO

Background: Kidney stone formation is closely related to renal epithelial cell damage and the adhesion of calcium oxalate crystals to cells. Methods: In this research, the adhesion of human kidney proximal tubular epithelial cells (HK-2) to calcium oxalate monohydrate crystals with a size of approximately 100 nm was studied. In addition, the inhibition of crystal adhesion by four tea polysaccharides (TPS0, TPS1, TPS2, and TPS3) with the molecular weights of 10.88, 8.16, 4.82, and 2.31 kDa, respectively were compared. Results: When oxalic acid-damaged HK-2 cells were repaired, cell viability increased. By contrast, reactive oxygen species level, phosphatidylserine eversion, and osteopontin expression decreased, thus indicating that tea polysaccharides have a repairing effect on damaged HK-2 cells. Moreover, after repairing the damaged cells, the amount of adherent crystals was reduced. The repair effect of tea polysaccharides is closely related to molecular weight, and TPS2 with the moderate molecular weight displayed the best repair effect. Conclusion: These results suggest that tea polysaccharides, especially TPS2, may inhibit the formation and recurrence of calcium oxalate kidney stones.


Assuntos
Oxalato de Cálcio/farmacologia , Polissacarídeos/farmacologia , Chá/química , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Cristalização , Fluorescência , Humanos , Nanopartículas/química , Osteopontina/metabolismo , Espécies Reativas de Oxigênio/metabolismo
15.
Bioorg Chem ; 88: 102948, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31054429

RESUMO

Eight new meroterpenoids with different types of monoterpene units, namely, magmenthanes A-H (1-8), were identified from the bark of Magnolia officinalis var. biloba. Magmenthane A (1) possesses a 1,3-dioxabicyclo [4.3.01,5] nonane skeleton, 1-5 possess five pairs of enantiomers and 6 possesses a 1,1'-diallyl-biphenyl fragment. The structures of 1-8 were elucidated on the basis of 1D and 2D NMR, HRESIMS and electronic circular dichroism (ECD) calculations. Compounds 5 and 8 displayed significant PTP1B inhibitory activities with IC50 values of 4.38 and 3.88 µM, respectively.

16.
Appl Opt ; 58(10): 2589-2595, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31045058

RESUMO

Infrared multilayer diffractive optical elements (MLDOEs) usually own microstructure heights of a few hundred micrometers. The design and fabrication of those elements are more difficult than MLDOEs working in the visible waveband, especially for MLDOEs with high numerical aperture and finite feature sizes. Based on scalar diffraction theory and manufacturing errors, the effective area method for improving diffraction efficiency of infrared MLDOEs is developed. Closed-form analytical relations among diffraction efficiency, microstructure heights, microstructure periods, and incident angles are derived and verified in the infrared waveband. Then, optimized microstructure heights of infrared MLDOEs with different microstructure zone widths in the infrared wavelengths 3-5 µm and 8-12 µm at normal incidence can be obtained. The results indicate that the microstructure heights of infrared MLDOEs determined by the method have higher diffraction efficiency than former design methods. The method is verified by the rigorous electromagnetic method. Finally, the influence of incident angles on infrared MLDOEs is investigated. Our results show that the suggested microstructure parameters of MLDOEs both produce higher diffraction efficiencies than that of structure designed by scalar diffraction theory and may lead to more efficient hybrid diffractive-diffractive optical systems based on MLDOEs.

17.
Comput Math Methods Med ; 2019: 1684218, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31019546

RESUMO

Pathological classification through transmission electron microscopy (TEM) is essential for the diagnosis of certain nephropathy, and the changes of thickness in glomerular basement membrane (GBM) and presence of immune complex deposits in GBM are often used as diagnostic criteria. The automatic segmentation of the GBM on TEM images by computerized technology can provide clinicians with clear information about glomerular ultrastructural lesions. The GBM region on the TEM image is not only complicated and changeable in shape but also has a low contrast and wide distribution of grayscale. Consequently, extracting image features and obtaining excellent segmentation results are difficult. To address this problem, we introduce a random forest- (RF-) based machine learning method, namely, RF stacks (RFS), to realize automatic segmentation. Specifically, this work proposes a two-level integrated RFS that is more complicated than a one-level integrated RF to improve accuracy and generalization performance. The integrated strategies include training integration and testing integration. Training integration can derive a full-view RFS1 by simultaneously sampling several images of different grayscale ranges in the train phase. Testing integration can derive a zoom-view RFS2 by separately sampling the images of different grayscale ranges and integrating the results in the test phase. Experimental results illustrate that the proposed RFS can be used to automatically segment different morphologies and gray-level basement membranes. Future study on GBM thickness measurement and deposit identification will be based on this work.

18.
Sensors (Basel) ; 19(8)2019 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-31003449

RESUMO

This research focuses on a desensitization method to develop a wide-range FBG sensor for extra-large strain monitoring, which is an essential requirement in large scale infrastructures or for some special occasions. Under appropriate hypotheses, the strain transfer distribution of wide-range FBG sensor based on the shear-lag theory is conducted to improve the accuracy of extra-large strain measurements. It is also discussed how the elastic modulus of adhesive layer affects the strain transfer rate. Two prototypes in different monitoring ranges are designed and fabricated by two layers of steel pipe encapsulation. The presented theoretical model is verified by experimental results. Moreover, it is demonstrated that experimentation in regards to the calibration of the wide-range FBG sensor, improved the amplification coefficient up to 2.08 times and 3.88 times, respectively. The static errors are both calculated and analyzed in this experiment. The wide-range FBG strain sensor shows favourable linearity and stability, which is an excellent property of sensors for extra-large strain monitoring.

19.
Int Arch Allergy Immunol ; 179(4): 304-319, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30982052

RESUMO

OBJECTIVES: To characterize the epithelial-mesenchymal transition (EMT) in chronic rhinosinusitis with nasal polyps (CRSwNP) and to investigate the mechanism by which microRNA-21 (miR-21) regulates EMT in CRSwNP. METHOD: (1) Tissue experiments: Mucosa tissues were collected from 13 patients with CRSwNP and 12 patients with CRS without nasal polyps (CRSsNP), as well as 11 patients without CRS (controls). Protein localization and quantification were achieved by immunofluorescence staining and Western blotting, involving the epithelial marker protein E-cadherin and the mesenchymal marker proteins α-smooth muscle actin (α-SMA), fibronectin, and vimentin. Quantitative RT-PCR was used to detect the relative expression levels of miR-21 and TGF-ß1 mRNAs. (2) Cellular experiments: Primary human nasal epithelial cells (PHNECs) treated with TGF-ß1, or TGF-ß1 with miR-21 inhibitor, or miR-21 mimics alone were observed for morphology changes under a phase-contrast microscope. The expression levels of epithelial/mesenchymal marker proteins were determined as aforementioned. PTEN and phosphorylated Akt were detected by Western blotting. RESULTS: (1) Tissue experiments: Compared with the CRSsNP and control groups, the expression of E-cadherin was downregulated in the CRSwNP group, whereas the expression of TGF-ß1, α-SMA, fibronectin, and vimentin was upregulated. The expression levels of miR-21 and TGF-ß1 mRNAs in CRSwNP were significantly higher than those in CRSsNP and controls. (2) Cellular experiments: TGF-ß1 induced EMT-like transformation in PHNECs, featured by changes in cell morphology and upregulation of mesenchymal proteins and miR-21. The miR-21 inhibitor, as well as the Akt-specific -inhibitor, suppressed TGF-ß1-induced EMT. Mechanically, downregulation of miR-21 resulted in increased PTEN and decreased Akt phosphorylation. Furthermore, overexpression of miR-21 had the opposite effects. CONCLUSIONS: Our findings suggest that the TGF-ß1-miR-21-PTEN-Akt axis may contribute to the pathogenesis of CRSwNP. miR-21 might be a reliable target for treating nasal polyp genesis through EMT suppression. Moreover, miR-21 inhibitors could be a novel class of antipolyp drug that modulates PTEN expression and Akt activation. In addition, further investigation regarding the reason underlying miR-21 overexpression in CRSwNP could provide a molecular target for novel treatment strategies for nasal polyposis.


Assuntos
Transição Epitelial-Mesenquimal , MicroRNAs/genética , Mucosa Nasal/fisiologia , Pólipos Nasais/imunologia , Rinite/imunologia , Sinusite/imunologia , Fator de Crescimento Transformador beta1/genética , Adolescente , Adulto , Idoso , Células Cultivadas , Criança , Doença Crônica , Feminino , Humanos , Masculino , MicroRNAs/metabolismo , Pessoa de Meia-Idade , Mucosa Nasal/patologia , Pólipos Nasais/genética , PTEN Fosfo-Hidrolase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Rinite/genética , Sinusite/genética , Fator de Crescimento Transformador beta1/metabolismo , Adulto Jovem
20.
Appl Opt ; 58(4): 927-934, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30874137

RESUMO

Form accuracy is an important parameter to measure whether a plastic lens can be used in imaging optics. Form accuracy exhibited by an aspheric plastic lens produced by injection molding is affected by process parameters and mold core. This paper proposes to optimize the process parameters through two stages. Stage one: An initial selection of process parameters was conducted in a wide range of the Taguchi method, and the process parameters were determined based on the signal-to-noise ratio, which significantly affected the axial deformation. Then the initial process parameters were obtained. Stage two: The regression model of process parameters was established according to the response surface methodology, with the optimal process parameters finally determined. For reducing the form accuracy error of aspheric plastic lens caused by material shrinkage and machining error of the mold core, an axial deformation compensation model was established. The aspheric plastic lens with form accuracy of 1.013 µm was experimentally verified, which met the requirements of imaging optics.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA