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1.
IEEE Trans Cybern ; 53(1): 592-606, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35468074

RESUMO

Capsule network (CapsNet) acts as a promising alternative to the typical convolutional neural network, which is the dominant network to develop the remaining useful life (RUL) estimation models for mechanical equipment. Although CapsNet comes with an impressive ability to represent entities' hierarchical relationships through a high-dimensional vector embedding, it fails to capture the long-term temporal correlation of run-to-failure time series measured from degraded mechanical equipment. On the other hand, the slow-varying dynamics, which reveals the low-frequency information hidden in mechanical dynamical behavior, is overlooked in the existing RUL estimation models (including CapsNet), limiting the utmost ability of advanced networks. To address the aforementioned concerns, we propose a slow-varying dynamics-assisted temporal CapsNet (SD-TemCapsNet) to simultaneously learn the slow-varying dynamics and temporal dynamics from measurements for accurate RUL estimation. First, in light of the sensitivity of fault evolution, slow-varying features are decomposed from normal raw data to convey the low-frequency components corresponding to the system dynamics. Next, the long short-term memory (LSTM) mechanism is introduced into CapsNet to capture the temporal correlation of time series. To this end, experiments conducted on an aircraft engine and a milling machine verify that the proposed SD-TemCapsNet outperforms the mainstream methods. In comparison with CapsNet, the estimation accuracy of the aircraft engine with four different scenarios has been improved by 10.17%, 24.97%, 3.25%, and 13.03% about the index root mean squared error, respectively. Similarly, the estimation accuracy of the milling machine has been improved by 23.57% compared to LSTM and 19.54% compared to CapsNet.

2.
Front Chem ; 9: 745347, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34568287

RESUMO

Due to the alarming speed of global warming, greenhouse gas removal from atmosphere will be absolutely necessary in the coming decades. Methane is the second most harmful greenhouse gas in the atmosphere. There is an emerging technology proposed to incorporating photocatalysis with solar updraft Towers (SUT) to remove methane from the air at a planetary scale. In this study, we present a deep analysis by calculating the potential of methane removal in relation to the dimensions and configuration of SUT using different photocatalysts. The analysis shows that the methane removal rate increases with the SUT dimensions and can be enhanced by changing the configuration design. More importantly, the low methane removal rate on conventional TiO2 photocatalyst can be significantly improved to, for example, 42.5% on a more effective Ag-doped ZnO photocatalyst in a 200 MW SUT while the photocatalytic reaction is the rate limiting step. The factors that may further affect the removal of methane, such as more efficient photocatalysts, night operation and reaction zone are discussed as possible solutions to further improve the system.

3.
Food Funct ; 12(3): 1207-1218, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33432947

RESUMO

Dapagliflozin alleviates hyperglycemia by increasing glycosuria, but it induces renal gluconeogenesis, thus neutralizing its efficacy. Resveratrol (Rsv), a natural polyphenolic chemical, improves insulin sensitivity in type 2 diabetes (T2D). Here, we investigated the regulatory effects and underlying mechanisms of Rsv on dapagliflozin-induced renal gluconeogenesis. Male ob/ob mice were given the vehicle (HF), dapagliflozin (1 mg kg-1), Rsv (10 mg kg-1), or dapagliflozin and Rsv combination for 10 weeks. Glucose metabolism was evaluated by glucose and pyruvate tolerance tests. HK-2 cells (human renal proximal tubule cells) were treated with dapagliflozin (1 µmol L-1) for 2 h and further incubated with Rsv (10 µmol L-1) for 12 h. The effects of Rsv on gluconeogenesis and insulin signaling were assessed. Dapagliflozin treatment increased glucose production in HK-2 cells and lowered blood glucose and induced gluconeogenesis in ob/ob mice. After Rsv treatment, the enhanced glucose production and gluconeogenesis were alleviated. The upregulated mRNA and protein expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) and the activation of the forkhead transcription factor O1 (FoxO1) protein in the dapagliflozin group were attenuated by Rsv administration. Rsv also improved renal insulin signaling by increasing PI3K and Akt phosphorylation. The PI3K inhibitor LY294002 dramatically decreased the p-Akt expression and activated FoxO1 by dephosphorylation, thus diminishing the inhibitory effects of Rsv on dapagliflozin-induced PEPCK and G6Pase expression. The data showed the mechanisms of Rsv in attenuating dapagliflozin-induced renal gluconeogenesis via activating the PI3K/Akt pathway and further suppressing FoxO1 activation, suggesting a potential intervention to achieve better glucose-lowering effects for SGLT2 inhibitors in T2D therapy.


Assuntos
Compostos Benzidrílicos/farmacologia , Gluconeogênese/efeitos dos fármacos , Glucosídeos/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Resveratrol/farmacologia , Animais , Antioxidantes/farmacologia , Linhagem Celular , Diabetes Mellitus Tipo 2/induzido quimicamente , Diabetes Mellitus Tipo 2/prevenção & controle , Dieta Hiperlipídica , Proteína Forkhead Box O1 , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Humanos , Masculino , Camundongos , Camundongos Obesos , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética , Distribuição Aleatória , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Regulação para Cima/efeitos dos fármacos
4.
Ying Yong Sheng Tai Xue Bao ; 31(3): 725-734, 2020 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-32537966

RESUMO

To clarify the morphological characteristics of soil preferential flow and the effect of plant roots on its formation, plants from the typical vegetation types of an artificial woodland (Leucaena acacia) and a dry watershed grassland (Heteropogon contortus) of Yuanmou County, Jinsha River were selected as the experimental objects. Based on the staining and tracing method combined with Photoshop CS5 and the Image-Pro Plus 6.0 image processing technology, we analyzed the morphological and distribution characteristics of soil preferential flow under the two planting types and examined the effects of plant roots. We found significant difference in soil preferential flow dyeing area between the woodland and grassland species, and the overall variation trend of the forestland dyeing area ratio decreased with increasing soil depth. The dyeing area of the grassland decreased monotonously with the increases of soil depth. The occurrence degree of soil preferential flow in forest was higher than that of grassland. Root systemaffected the formation of soil preferential flow. At the root diameter ranges of 0≤d≤5 mm and d>10 mm, root length density of the woodland showed a monotonous decreasing trend with increasing soil depth, while in the root diameter range of 5 mm5 mm. The overall change trend of soil preferential flow dyeing area of two vegetation types in the study area decreased with increasing soil depth. Plant root system was closely related to the formation of soil preferential flow. Fine roots could promote while coarse roots may retard the formation of preferential flows.


Assuntos
Rios , Solo , China , Florestas , Pradaria , Raízes de Plantas
5.
Diagn Pathol ; 15(1): 18, 2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-32093712

RESUMO

BACKGROUND: Insulin resistance (IR) in obesity is associated with the occurrence of metabolic and cardiovascular diseases. Dipepidyl peptidase 4 (DPP4) plays a pivotal role during the development of IR, and was found to be a target gene of microRNA-214 (miR-214) in our study. This study sought to assess the expression and clinical value of miR-214 in obese patients with IR, and investigate its therapeutic potential in obese rats and adipocytes with IR. METHODS: Serum expression of miR-214 in obese patients with or without IR was estimated by quantitative real-time-PCR. A receiver operating characteristic curve was plotted to evaluate the diagnostic value of miR-214 in the patients. Obesity-induced IR animal and cell models were constructed, and the therapeutic ability of miR-214 was explored. RESULTS: Serum expression of miR-214 was decreased in obese patients compared with the healthy controls, and the lowest expression was observed in the cases with IR. Downregulation of miR-214 was significantly correlated with the serum DPP4 levels and HOMA-IR of the patients upon IR conditions, and was demonstrated to perform diagnostic accuracy for distinguishing obese patients with IR from those without IR. In obesity-associated IR animal and cell models, the downregulation of miR-214 was also been detected. According to the measurement of glucose and insulin tolerance and glucose uptake abilities, we found that the overexpression of miR-214 could be used to alleviate IR in the IR models, especially when collaboratively used with DPP4 inhibitor vildagliptin. CONCLUSION: All data revealed that miR-214, as a regulator of DPP4, is decreased in obese patients with IR and may serve as a diagnostic biomarker. The upregulation of miR-214 could improve IR in obese rats and adipocytes, indicating that miR-214 has the therapeutic potential for obesity and IR.


Assuntos
Resistência à Insulina/genética , MicroRNAs/genética , Adipócitos/metabolismo , Animais , Biomarcadores/sangue , Feminino , Humanos , Masculino , Camundongos , Obesidade/genética , Ratos Sprague-Dawley
6.
Diabetes Metab Syndr Obes ; 12: 2635-2644, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31849507

RESUMO

PURPOSE: Dipeptidyl peptidase 4 (DPP4) is one of the newly identified adipokines, which acts as paracrine in adipose tissue and as endocrine hormones in the liver, muscles and central nervous system. Expression of DPP4 was significantly upregulated in obese patients upon insulin resistance (IR) conditions, but the mechanism underlying the dysregulation of DPP4 remains unclear. This study aimed to investigate the DPP4 expression in adipose tissue and adipocytes under IR conditions or with liraglutide intervention, and explore the potential molecular mechanisms. METHODS: Obesity-associated IR animal and cell models were, respectively, constructed by using high-fat diet and palmitic acid (PA) stimulation. Expression of DPP4 in adipose tissues and adipocytes was estimated by quantitative real-time RT-PCR and Western-blot. Effects of the AMPK/JAK2/STAT3 pathway on DPP4 were examined by regulating the activity of AMPK and the JAK2/STAT signaling. The therapeutic efficacy of liraglutide in the IR models was evaluated, and its regulatory effects on DPP4 expression and the underlying molecular mechanisms were explored. RESULTS: The expression of DPP4 was markedly upregulated in both the animal and cell IR models. In the adipocyte, DPP4 expression was found to be suppressed by the activation of AMPK, and this inhibition effect was mediated by the JAK2/STAT3 signaling. Moreover, liraglutide could alleviate the obesity-induced IR, and led to the downregulation of DPP4 in IR animal and cell models. Liraglutide intervention resulted in the activation of AMPK and deactivation of the JAK2/STAT3 signaling in the adipocytes. CONCLUSION: Taken together, the expression of DPP4 is upregulated in adipose tissues and adipocytes upon IR conditions, but is reduced after liraglutide intervention. The dysregulation of DPP4 in the adipocytes may be performed by the AMPK/JAK2/STAT3 pathway.

8.
Chin Med J (Engl) ; 129(15): 1784-8, 2016 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-27453225

RESUMO

BACKGROUND: The aim of this study was to evaluate the efficacy of ultrasonic features in predicting the malignancy of thyroid nodules in a group of Chinese patients. METHODS: In all, 762 patients with thyroid nodules (424 malignant and 338 benign) underwent ultrasound (US) check and surgery between March 2011 and July 2014 at Peking University First Hospital were identified. Univariate and receiver operating characteristic (ROC) analyses were performed to calculate the sensitivity, specificity, negative and positive predictive values of each US feature, and the accuracy of their combinations for prediction of malignancy. RESULTS: Patients with malignant nodules were younger and without obvious risk history than those in the benign group (P < 0.001, P = 0.93). No individual US sign was fully predictive of a malignant lesion. The Youden indexes of irregular margins and hypoechogenicity were the first and second highest in all US features, which were 51.9% and 45.2%, respectively. The sensitivity of solid components (89.7%) and hypoechogenicity (89.2%) and the specificity of taller-than-wide shape (98.5%) and microcalcifications (90.6%) were the first and second highest in all US features. Intranodular flow on a color Doppler examination was a weak predictor of malignancy. Under ROC analysis excepting intranodular flow, the 95% confidence interval (CI) of areas under the curves of hypoechogenicity and irregular margins with any one of the US features were overlapped that of five-feature combinations (95% CI: 0.850-0.901). CONCLUSIONS: We should be alert with taller-than-wide shape and microcalcifications. Intranodular flow was a weak predictor of malignancy. According to Youden indexes and ROC analysis, irregular margins and hypoechogenicity combined with solid component or taller-than-wide shapes or microcalcifications have a high predicative value for malignant thyroid nodules in Chinese patients.


Assuntos
Neoplasias da Glândula Tireoide/diagnóstico , Nódulo da Glândula Tireoide/diagnóstico , Ultrassonografia/métodos , Adolescente , Adulto , Povo Asiático , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROC , Estudos Retrospectivos , Sensibilidade e Especificidade , Adulto Jovem
9.
Drug Des Devel Ther ; 9: 1177-84, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25733821

RESUMO

Liraglutide, a glucagon-like peptide-1 analog, has been proved to reduce body weight and visceral adipose tissue (VAT) in human studies. In this study, we aimed at examining lipogenetic signal changes in VAT after weight-loss with liraglutide in db/db mice. The mice were divided into two groups: liraglutide-treated group (n=14, 8-week-old, fasting glucose. >10 mmol/L, liraglutide 300 µg/kg twice a day for 4 weeks) and control group (n=14, saline). We found body weight gain and food intake were reduced after liraglutide treatment (P<0.05). Compared to the control group, the VAT weights were significantly lower in the treated group (2.32±0.37 g versus 3.20±0.30 g, P<0.01) than that in control group. In VAT, compared with control group, the lipogenetic transcription factors PPARγ and C/EBPα expressions were both reduced with pAMPK and pACC increased 3.5-fold and 2.31-fold respectively, while pAkt and pP38MAPK were reduced 0.38-fold and 0.62-fold respectively (P<0.01). In conclusion, VAT was reduced after weight loss with AMPK activation and Akt suppression with liraglutide treatment, which was associated with reduction of lipogenetic process in VAT.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Gordura Intra-Abdominal/efeitos dos fármacos , Lipídeos/antagonistas & inibidores , Liraglutida/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Animais , Ativação Enzimática/efeitos dos fármacos , Injeções Subcutâneas , Gordura Intra-Abdominal/metabolismo , Lipídeos/biossíntese , Liraglutida/administração & dosagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Proteínas Proto-Oncogênicas c-akt/metabolismo , Relação Estrutura-Atividade
10.
J Colloid Interface Sci ; 429: 25-33, 2014 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-24935186

RESUMO

In this study, the application of Mn loaded MCM-41 (Mn/MCM-41) was reported as a novel adsorbent for methyl blue (MB) from aqueous solution. The mesoporous structure of Mn/MCM-41 was confirmed by XRD technique. Surface area, pore size and wall thickness were calculated from BET equation and BJH method using nitrogen sorption technique. FT-IR studies showed that Mn were loaded on the hexagonal mesoporous structures of MCM-41. It is found that the MCM-41 structure retained after loading of Mn but its surface area and pore diameter decreased due to pore blockage. Adsorption of MB from aqueous solution was investigated by Mn/MCM-41 with changing Mn content, adsorbent dosage, initial MB concentration, contact time, pH and the temperature. Under the chosen condition (25°C, 0.02 g adsorbent dosage, 6.32 pH, 50 mg L(-1) MB, 1 wt.% Mn), a high MB adsorption capacity (45.38 mg g(-1)) was achieved by Mn/MCM-41 process at 120 min, 8.6 times higher than MCM-41. The electrostatic interaction was considered to be the main mechanism for the dye adsorption. The experimental data fitted well to Freundlich and Dubinin-Radushkevich isotherms. The adsorption of MB on Mn/MCM-41 followed pseudo-second-order kinetics. Thermodynamic parameters suggested that the adsorption process is endothermic and spontaneous.

11.
Peptides ; 52: 134-42, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24406898

RESUMO

Glucagon-like peptide-1 (GLP-1) has been proved to have effects of anti-hyperglycemia and ß-cell preservation. However, it is still unclear whether there are differences between early and late GLP-1 intervention in type 2 diabetes mellitus (T2DM). We divided the mice into 5 groups: early treated group (n=7, 8-week old, fasting glucose>10mmol/l), late treated group (n=7, 10-week old, fasting glucose>20mmol/l), early control group (n=7), late control group (n=7) and wild type group (n=7). Treated group was injected with liraglutide (a GLP-1 analog) 300µg/kg bid for 4 weeks, while control group was given saline at the same time. The results showed that compared with control group, food intake and body weight gain were reduced in both early and late treated group (p<0.05), and there was no significance between the two treated groups. Early liraglutide intervention showed better improvements in glucose control, acute insulin response to glucose (AIRg) and disposition index (before vs. after treatment, AIRg 1.01±0.53 vs. 2.98±0.63, disposition index 10.81±0.89 vs. 27.4±2.15) than late intervention (AIRg 0.99±0.02 vs. 1.41±0.32, disposition index 3.47±0.38 vs. 6.43±1.62, p=0.001). The histopathology of the pancreas showed the estimated ß-cell mass (BCM) was increased more in early treated group than that in late one (0.03 vs. 0.01g). Expressions of the proliferation related genes PDX-1, MafA and GLP-1 receptor (GLP-1R) in early treated group were 1.81, 2.57 and 1.59 times as much as that in late treated group. In conclusion, early liraglutide intervention was better in glucose control, ß-cell function improvement and ß-cell mass preservation.


Assuntos
Índice de Massa Corporal , Ingestão de Alimentos/efeitos dos fármacos , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Glucose/metabolismo , Hipoglicemiantes/farmacologia , Células Secretoras de Insulina/metabolismo , Animais , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Peptídeo 1 Semelhante ao Glucagon/farmacologia , Receptor do Peptídeo Semelhante ao Glucagon 1 , Proteínas de Homeodomínio/biossíntese , Células Secretoras de Insulina/patologia , Liraglutida , Fatores de Transcrição Maf Maior/biossíntese , Masculino , Camundongos , Receptores de Glucagon/biossíntese , Transativadores/biossíntese
12.
Sci China Life Sci ; 56(11): 1014-9, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24114445

RESUMO

During the early mid-1990s, a number of rural farmers across central China were employed to the unregulated plasmaselling-activity and many of them were infected by HIV-1. However, AIDS progression in the former blood donors (FBDs) is various. The aim of this study is to assess human leukocyte antigen (HLA) class I allele distribution in FBDs and evaluate its association with HIV-1 infection and disease progression. A total of 353 FBDs were enrolled in the cohort including 294 ART naïve HIV-1 seropositive and 59 HIV-1 seronegative age-matched subjects. The viral load and CD4/CD8 T cell counts were assessed in all subjects. Compared with HIV-seropositive group, the frequency of HLA-A 03 in control was significantly higher. After classifying the HLA-B alleles of the subjects according to the presence of Bw4/Bw6 serological epitopes, detrimental effect of HLA Bw6/ Bw6 homozygosity was also confirmed in the HIV-seropositive subjects. This study provides novel evidence on HLA class I allele distribution and association of HLA-A 03 frequency with HIV-1 infection and viremia in the HIV-1 infected FBDs, which may throw light on intervention strategy for the HIV-1 infection and our understanding how host immunity and genetic background affect HIV infection and AIDS progression.


Assuntos
Frequência do Gene , Infecções por HIV/genética , HIV-1 , Antígeno HLA-A3/genética , Adulto , Estudos de Casos e Controles , China , Estudos de Coortes , Progressão da Doença , Feminino , Humanos , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Carga Viral , Viremia/genética
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