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1.
Entropy (Basel) ; 23(12)2021 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-34945938

RESUMEN

To determine the effects of Ti and mixing entropy (ΔSmix) on the structure and mechanical proper-ties of Zr-Ta alloys and then find a new potential energetic structural material with good me-chanical properties and more reactive elements, TixZr2.5-xTa (x = 0, 0.5, 1.0, 1.5, 2.0) alloys were investigated. The XRD experimental results showed that the phase transformation of TixZr2.5-xTa nonequal-ratio ternary alloys depended not on the value of ΔSmix, but on the amount of Ti atoms. With the addition of Ti, the content of the HCP phase decreased gradually. SEM analyses revealed that dendrite morphology and component segregation increasingly developed and then weakened gradually. When x increases to 2.0, TixZr2.5-xTa with the best mechanical properties can be ob-tained. The yield strength, compressive strength and fracture strain of Ti2.0Zr0.5Ta reached 883 MPa, 1568 MPa and 34.58%, respectively. The dependence of the phase transformation and me-chanical properties confirms that improving the properties of Zr-Ta alloys by doping Ti is feasible.

2.
Environ Technol ; 35(13-16): 1916-27, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24956785

RESUMEN

Green manuring is a common practice in replenishment of soil organic matter and nutrients in rice paddy field. Owing to the complex interplay of multiple factors, the oxidation--reduction (redox) properties of dissolved organic matter (DOM) from green manure crops are presently not fully understood. In this study, a variety of surrogate parameters were used to evaluate the redox capacity and redox state of DOM derived from Chinese milk vetch (CMV, Astragalus sinicus L.) via microbial decomposition under continuously flooded (CF) and non-flooded (NF) conditions. Additionally, the correlation between the surrogate parameters of CMV-DOM and the kinetic parameters of relevant redox reactions was evaluated in a soil-water system containing CMV-DOM. Results showed that the redox properties of CMV-DOM were substantially different between the fresh and decomposed CMV-DOM treatments. Determination of the surrogate parameters via ultraviolet-visible/Fourier transform infrared absorption spectroscopy and gel permeation chromatography generally provided high-quality data for predicting the redox capacity of CMV-DOM, while the surrogate parameters determined by elemental analysis were suitable for predicting the redox state of CMV-DOM. Depending on the redox capacity and redox state of various moieties/components, NF-decomposed CMV-DOM could easily accelerate soil reduction by shuttling electrons to iron oxides, because it contained more reversible redox-active functional groups (e.g. quinone and hydroquinone pairs) than CF-decomposed CMV-DOM. This work demonstrates that a single index cannot interpret complex changes in multiple factors that jointly determine the redox reactivity of CMV-DOM. Thus, a multi-parametric study is needed for providing comprehensive information on the redox properties of green manure DOM.


Asunto(s)
Agricultura/métodos , Planta del Astrágalo/química , Suelo , Carbohidratos/análisis , Ácidos Carboxílicos/análisis , Compuestos Ferrosos/análisis , Oxidación-Reducción , Preparaciones de Plantas/química , Análisis de Componente Principal , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja por Transformada de Fourier
3.
Materials (Basel) ; 15(2)2022 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-35057303

RESUMEN

To study the influence of nano-additives on the friction-wear characteristics of friction materials, the nano-sized silicon carbide particles which have excellent chemical and physical properties are considered to add in composite to form the modified friction material. The influence of the silicon carbide nanoparticles (SCN) on the friction-wear characteristics of copper-based friction materials (CBFM) is investigated via the SAE#2 (made in Hangzhou, China) clutch bench test with the applied pressure, rotating speed, and automatic transmission fluid (ATF) temperature taken into account. Moreover, the variations of friction torque and temperature are considered to evaluate the friction performance, and the variable coefficient is employed to describe the friction stability. The wear characteristics of friction materials are investigated by the disc changes in thickness and micro-morphology. The results show that the CBFM with SCN can provide a higher friction torque, which increased by 30% to 50% compared with CBFM. The variable coefficient of CBFM with SCN changes from 674 to 52 with the rotating speed raised from 600 rpm to 3000 rpm, which shows that the friction stability is relatively worse. Furthermore, the micromorphology shows that the CBFM with SCN has lower porosity and surface roughness, which increases the microscopic contact area and the coefficient of friction (COF). Simultaneously, the reduction in porosity also leads to a decrease in the cooling quality, bringing about a rapid temperature rise. Thus, the wear amount of CBFM with SCN increases significantly, especially for the friction disc in the axial middle position.

4.
Exp Mol Pathol ; 87(1): 27-31, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19450578

RESUMEN

OBJECTIVES: It was found that alpha-enolase was dramatically up-regulated in the hypertrophic hearts of SHR in our previous study. The purposes of this study were to examine the expression pattern of alpha-enolase in pre- and postnatal myocardium of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats, and to explore the relationship between the overexpression of alpha-enolase and left ventricular hypertrophy. METHODS: HE staining was used for the measurement of cardiac hypertrophy. Immunohistochemical technique was used to evaluate the location of alpha-enolase. The expressions of alpha-enolase in the left cardiac ventricles at different development times were examined by Real-time RT-PCR and Western blot. RESULTS: Cardiac hypertrophy was found in SHR rats at 4 weeks of age and remained up to 24 weeks of age. The signals of alpha-enolase protein were strong and existed extensively in hypertrophic myocardium in SHR, while in the normal myocardium of WKY, the signals were scarcely found and weak. The levels of alpha-enolase mRNA and protein in SHR and WKY hearts during fetal stage and newborn stage were similar, while from 4 weeks of age to 24 weeks of age, accompanied by the cardiac hypertrophy, the levels of alpha-enolase mRNA and protein in left ventricle of SHR were significantly higher than that in WKY. CONCLUSIONS: The expressions of alpha-enolase in the left ventricle of the rats during normal and pathological cardiac development were different. This phenomenon provides the potential clues to understanding pathophysiological mechanisms in cardiac hypertrophy of SHR.


Asunto(s)
Regulación Enzimológica de la Expresión Génica , Corazón/fisiología , Hipertrofia Ventricular Izquierda , Miocardio/patología , Fosfopiruvato Hidratasa/metabolismo , Animales , Femenino , Humanos , Hipertrofia Ventricular Izquierda/patología , Hipertrofia Ventricular Izquierda/fisiopatología , Masculino , Miocardio/metabolismo , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Fosfopiruvato Hidratasa/genética , Embarazo , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY
5.
Curr Vasc Pharmacol ; 13(4): 467-74, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25360842

RESUMEN

Extracellular signal regulated kinase½ (ERK1/2) signaling is critical to endothelin-1 (ET-1)-induced cardiomyocyte hypertrophy. This study was to investigate ERK1/2 signaling and hypertrophic response to ET-1 stimulation in cardiomyocytes (CMs) from spontaneous hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Primary neonatal SHR and WKY CMs were exposed to ET-1 for up to 24 hrs. Minimal basal ERK1/2 phosphorylation was present in WKY CMs, while a significant baseline ERK1/2 phosphorylation was observed in SHR CMs. ET-1 induced a time- and dose-dependent increase in ERK1/2 phosphorylation in both SHR and WKY CMs. However, ET-1-induced ERK1/2 activation occurred much earlier with significantly higher peak phosphorylation level, and stayed elevated for longer duration in SHR CMs than that in WKY CMs. ET-1-induced hypertrophic response was more prominent in SHR CMs than that in WKY CMs as reflected by increased cell surface area, intracellular actin density, and protein synthesis. Pre-treatment with ERK1/2 phosphorylation inhibitor PD98059 completely prevented ET-1-induced ERK1/2 phosphorylation and increases in cell surface area and protein synthesis in SHR and WKY CMs. The specific PI3 kinase inhibitor LY294002 blocked ET-1-induced Akt and ERK1/2 phosphorylation, and protein synthesis in CMs. These data indicated that ERK1/2 signaling was differentially enhanced in CMs, and was associated with increased cardiac hypertrophic response to ET-1 in SHR. ET-1-induced ERK1/2 activation and cardiac hypertrophy appeared to be mediated via PI3 kinase/Akt signaling in SHR and WKY. The differential ERK1/2 activation in SHR CMs by ET-1 might represent a potential target for combination therapy of hypertension.


Asunto(s)
Cardiomegalia/metabolismo , Endotelina-1/farmacología , Hipertensión/tratamiento farmacológico , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Miocitos Cardíacos/efectos de los fármacos , Animales , Western Blotting , Cardiomegalia/patología , Técnicas de Cultivo de Célula , Tamaño de la Célula/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Quimioterapia Combinada , Endotelina-1/metabolismo , Hipertensión/metabolismo , Hipertensión/patología , Inmunohistoquímica , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Inhibidores de las Quinasa Fosfoinosítidos-3 , Fosforilación , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Ratas Endogámicas SHR , Ratas Endogámicas WKY
6.
Sci Rep ; 5: 13297, 2015 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-26293686

RESUMEN

In a time of increasing economic constraints, it is crucial that health systems optimize their resource use to ensure that they generate the maximum possible health gain. Therefore, it is necessary for health interventions to be evaluated and compared across therapeutic boundaries. Undertaking such an evaluation a generic utility-based measure is required. But it remains uncertain whether the utility values obtained by direct or indirect methods are comparable and which approach is the most appropriate in Systemic Lupus Erythematosus (SLE) population. In the study, we compared the utility values obtained by an indirect method (EQ-5D) with direct utility instruments, the standard gamble (SG) and visual analog scale (VAS), in SLE patients. The correlations between VAS, EQ-5D and LupusQoL were significant; relative good intraclass correlations or kappa coefficients indicated the reliability of these instruments. A model incorporating the SLEDAI scores and LupusQoL domains of emotional health and pain was a good predictor of VAS. SLEDAI score was a good predictor in the SG regression model. These findings suggested that the VAS and EQ-5D might be valid and reliable measures to assess health related quality of life in SLE patients and represent promising outcome measures for future research in this population.


Asunto(s)
Estado de Salud , Lupus Eritematoso Sistémico/terapia , Aceptación de la Atención de Salud , Adulto , Demografía , Femenino , Humanos , Masculino , Calidad de Vida , Análisis de Regresión , Reproducibilidad de los Resultados , Índice de Severidad de la Enfermedad , Estadísticas no Paramétricas
7.
Eur J Pharmacol ; 473(1): 1-7, 2003 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-12877931

RESUMEN

In Parkinson's disease, neuroprotective therapy to rescue dopamine neurons has been proposed. Ginsenoside Rg1, one of the biologically active ingredients of ginseng, may be a candidate neuroprotective drug. In the present study, the mechanism underlying the neuroprotection provided by ginsenosde Rg1 was studied against apoptosis induced by exogenous dopamine in PC12 cells. Pretreatment with ginsenoside Rg1 markedly reduced the generation of dopamine-induced reactive oxygen species and the release of mitochondrial cytochrome c into the cytosol, and subsequently inhibited the activation of caspase-3. In addition, Rg1 pretreatment also reduced inducible nitric oxide (NO) synthase protein level and NO production. These results suggested that ginsenoside Rg1 may attenuate dopamine-induced apoptotic cell death through suppression of intracellular oxidative stress, and that it may rescue or protect dopamine neurons in Parkinson's disease.


Asunto(s)
Antioxidantes/farmacología , Apoptosis/efectos de los fármacos , Dopamina/metabolismo , Ginsenósidos/farmacología , Fármacos Neuroprotectores/farmacología , Estrés Oxidativo/efectos de los fármacos , Animales , Western Blotting , Caspasa 3 , Inhibidores de Caspasas , Caspasas/metabolismo , Grupo Citocromo c/efectos de los fármacos , Grupo Citocromo c/metabolismo , Fragmentación del ADN , Dopamina/farmacología , Citometría de Flujo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo II , Células PC12 , Panax/química , Ratas
8.
PLoS One ; 9(5): e97952, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24848431

RESUMEN

OBJECTIVE: To evaluate the psychometric properties and clinical utility of Chinese Multidimensional Health Assessment Questionnaire (MDHAQ-C) in patients with rheumatoid arthritis (RA) in China. METHODS: 162 RA patients were recruited in the evaluation process. The reliability of the questionnaire was tested by internal consistency and item analysis. Convergent validity was assessed by correlations of MDHAQ-C with Health Assessment Questionnaire (HAQ), the 36-item Short-Form Health Survey (SF-36) and the Hospital anxiety and depression scales (HAD). Discriminant validity was tested in groups of patients with varied disease activities and functional classes. To evaluate the clinical values, correlations were calculated between MDHAQ-C and indices of clinical relevance and disease activity. Agreement with the Disease Activity Score (DAS28) and Clinical Disease Activity Index (CDAI) was estimated. RESULTS: The Cronbach's alpha was 0.944 in the Function scale (FN) and 0.768 in the scale of psychological status (PS). The item analysis indicated all the items of FN and PS are correlated at an acceptable level. MDHAQ-C correlated with the questionnaires significantly in most scales and scores of scales differed significantly in groups of different disease activity and functional status. MDHAQ-C has moderate to high correlation with most clinical indices and high correlation with a spearman coefficient of 0.701 for DAS 28 and 0.843 for CDAI. The overall agreement of categories was satisfying. CONCLUSION: MDHAQ-C is a reliable, valid instrument for functional measurement and a feasible, informative quantitative index for busy clinical settings in Chinese RA patients.


Asunto(s)
Artritis Reumatoide/psicología , Encuestas Epidemiológicas/métodos , Encuestas y Cuestionarios , Adulto , Anciano , China , Femenino , Humanos , Lenguaje , Masculino , Persona de Mediana Edad , Psicometría , Reproducibilidad de los Resultados , Adulto Joven
9.
PLoS One ; 9(6): e98883, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24892282

RESUMEN

OBJECTIVE: To investigate the construct and criterion validity of the Euro Qol-5D (EQ-5D), which allows quality-adjusted life-years to be calculated, in patients with systemic lupus erythematosus (SLE). METHODS: Consecutive SLE patients who had been followed at the Renji Hospital, School of Medicine, Shanghai Jiao Tong University were recruited. Cross-sectional correlations of the EQ-5D with equivalent domains in disease-specific health-related quality of life (HRQoL), LupusQol, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) measures, the Systemic Lupus International Collaborating Clinics Damage Index (SDI), and patient characteristics were tested. Discriminant validity to assess the ability to distinguish between patients of different disease severity was assessed. There also were evaluations of ceiling and floor effects. RESULTS: 240 patients were recruited in total. The EQ-5D correlated moderately to strongly with all domains of the LupusQoL (r: 0.44-0.7) apart from intimate relationships (r = 0.25) and body image (r = 0.18). There was moderate negative correlation between EQ-5D and clinical assessment of disease, SLEDAI (r = -0.589) and SDI (r = -0.509). When compared with equivalent domains on LupusQoL, there was good construct validity in EQ-5D (r: 0.631-0.812). EQ-5D could also discriminate patients with varied disease severity (according SLEDAI and SDI). There was no floor effect in EQ-5D but the ceiling effect remains strong (34%). CONCLUSION: Our results provide sufficient evidence that the EQ-5D displays construct and criterion validity for use in SLE patients. Disease-specific measures of HRQoL used alongside may be a better choice.


Asunto(s)
Lupus Eritematoso Sistémico/epidemiología , Calidad de Vida , Años de Vida Ajustados por Calidad de Vida , Adulto , China/epidemiología , Estudios Transversales , Femenino , Humanos , Masculino , Vigilancia en Salud Pública , Adulto Joven
10.
Arthritis Res Ther ; 14(3): R103, 2012 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-22551315

RESUMEN

INTRODUCTION: Glucocorticoid (GC) therapy remains important in improving the prognosis of patients with systemic lupus erythematosus (SLE). However, some patients do not achieve an effective response with GC treatment, creating an obstacle to the remission of SLE. Identification of the underlying mechanisms responsible for steroid resistance can be significant. Macrophage migration inhibitory factor (MIF) arouses our interest because of its reciprocal relationship with GCs. In the present study, we investigated for the first time whether MIF correlated with steroid resistance in SLE and explored potential mechanisms of action. METHODS: Sixty-two patients with SLE (40 steroid sensitive and 22 steroid resistant) and 21 normal controls were recruited. Serum levels of MIF were measured by ELISA. Cytosolic MIF and IκB expression in peripheral blood mononuclear cells (PBMCs) were determined by western blotting. The electrophoretic mobility shift assay was assessed by NF-κB in nuclear aliquots. Gene silencing was applied to reduce expression of MIF in PBMCs in steroid-resistant patients. PBMCs obtained from steroid-sensitive patients were treated with recombinant human MIF of different concentrations. RESULTS: MIF levels in serum and PBMCs were higher in steroid-resistant patients compared with steroid-sensitive patients and controls. In contrast to the steroid-sensitive group, NF-κB levels were significantly higher and IκB levels lower in steroid-resistant patients. After MIF gene silencing, IκB levels in cells from steroid-resistant patients were increased. In steroid-sensitive patients, a decrease in IκB levels and an increase in NF-κB expression from baseline were detected in PBMCs treated with a higher concentration of recombinant human MIF. Treatment with recombinant human MIF did not regulate expression of IκB and NF-κB in PBMCs from patients treated with an anti-MIF monoclonal antibody. CONCLUSIONS: Our results indicated that MIF may play a role in the formation of steroid resistance in SLE by affecting the NF-κB/IκB signaling cascade. As a regulator of glucocorticoid sensitivity, MIF may be a potential target for steroid sparing.


Asunto(s)
Resistencia a Medicamentos/fisiología , Oxidorreductasas Intramoleculares/metabolismo , Lupus Eritematoso Sistémico/metabolismo , Factores Inhibidores de la Migración de Macrófagos/metabolismo , Adulto , Western Blotting , Ensayo de Cambio de Movilidad Electroforética , Ensayo de Inmunoadsorción Enzimática , Femenino , Glucocorticoides/uso terapéutico , Humanos , Quinasa I-kappa B/metabolismo , Oxidorreductasas Intramoleculares/análisis , Leucocitos Mononucleares/metabolismo , Lupus Eritematoso Sistémico/tratamiento farmacológico , Factores Inhibidores de la Migración de Macrófagos/análisis , Masculino , FN-kappa B/metabolismo , ARN Interferente Pequeño , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/fisiología , Transfección
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