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A wake oscillator model is presented for the stream-wise vortex-induced vibration of a circular cylinder in the second excitation region. The near wake dynamics related to the fluctuating nature of alternate vortex shedding is modeled based on the classical van der Pol equation. An appropriate approach used in cross-flow VIV is developed to estimate the model empirical parameters. The comparison between our calculations and experiments is carried out to validate the proposed model. It is found that the present model results agree fairly well with the experimental data. [ABSTRACT FROM AUTHOR]

Abstract: FeCu/SiO2 catalysts, in which K or Na promoter is incorporated respectively, are prepared by a combination method of continuous co-precipitation and spray drying technology. The catalysts were characterized by temperature-programmed desorption and Mössbauer spectroscopy. The Fischer–Tropsch synthesis (FTS) performance of the catalysts was studied in a continuously stirred tank slurry reactor. The basicity of the K-promoted catalyst is enhanced, as demonstrated by CO2-TPD results. MES results show that sodium can weaken the dispersion of α-Fe2O3 phase; either potassium or sodium can promote carburization of the catalyst, while the effect of sodium is weaker. FTS results indicate that the addition of K or Na can improve the catalyst activity, and shift the product distribution to heavy hydrocarbons to the different extent. [Copyright &y& Elsevier]

The natural deep eutectic solvent (NADES) was used as the extraction solvent to extract the four ingredients from Chuanxiong-Honghua. NADES-7 composed of L-proline and lactic acid (1:2) has a better extraction effect compared with traditional solvents. The extraction process was optimized using response surface methodology (RSM) and ant colony algorithm-enabled backpropagation neural network (ACO-BPNN), which were compared with each other. ACO-BPNN has a higher R2 and predictive value than RSM. The optimal process parameters predicted by the ACO-BPNN were determined to be as follows: solvent-to-material ratio, 8 mL/g; extraction time, 67 min; water concentration, 48%; and extraction temperature, 50 °C. The best predicted comprehensive evaluation value was 4.2634, and the mean value obtained from the experiment was 3.8678. Compared with traditional solvents, the antioxidant activity of NADES-7 extract was better, and the mean value of DPPH, FRAP (ferric reducing antioxidant power), and ABTS assays were 0.1555, 0.1132, and 0.0894 mmol Trolox/g dry weight, respectively. Experimental results show that ACO-BPNN can better optimize the extraction process of many different polar compounds in plant combinations. • NADES-7 was selected as a better Chuanxiong-Honghua (CH) extraction. • ACO-BPNN can better optimize the CH extraction process than RSM. • The NADES-7 extract of CH had better in vitro antioxidant activity than the water, methanol, and 75% methanol. [ABSTRACT FROM AUTHOR]

Abstract: Ethnopharmacological relevance: Danhong injection (DHI), a Chinese medical product extracted from Radix et Rhizoma Salviae Miltiorrhizae (Salvia miltiorrhiza Bge., Labiatae, Danshen in Chinese) and Flos Carthami (Carthamus tinctorius L., Compositae, Honghua in Chinese), has been reported to have anti-inflammatory, anti-oxidative and anti-fibrinolytic properties and is used extensively for the clinical treatment of cardiovascular disease in clinic. This study aimed to investigate the preventive and therapeutic effects of DHI on hyperlipidemia. Materials and methods: Forty-eight adult male Sprague-Dawley rats were randomly divided into four groups: normal control (NC), model control (MC) and DHI-treated at doses of 1.0mL/kg and 2.0mL/kg. The effects of DHI on serum triglyceride (TG), total cholesterol (TC), glucose, high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) were evaluated and insulin was determined by enzyme-linked immunosorbent assay (ELISA). Moreover, the expression of acetyl-CoA carboxylase 1 (ACC1), fatty acid synthase (FAS), carnitine palmitoyl transferase 1 (CPT1), hydroxymethylglutaryl-CoA reductase (HMGR) and peroxisome proliferator-activated receptor alpha (PPAR-α) in liver were determined by real-time PCR. Results: Compared with the MC group, rats treated with DHI had significantly reduced TG, TC, LDL-C and arteriosclerosis index (AI). Expression of FAS and HMGR mRNA was significantly reduced, whereas the CPT1 and PPAR-α were significantly increased. Conclusion: DHI treatment was accompanied by significantly increased lipolysis in the liver and decreased fatty acid synthesis. The insights gained from this study will improve both understanding of the mechanisms involved in the effect of DHI on hyperlipidemia and the pharmacological rationale for the use of DHI in diseases caused by lipid metabolic disorders. [Copyright &y& Elsevier]

• Environmental and economic benefits are involved so that non-toxic and high-solubility ethanol is used as a solvent. • Extraction and pharmacology is simultaneously considered in optimization. • The local valleys and sharper ridge surfaces can be obtained by 3D BPNN predicted surfaces as compared with 3D RSM. Dried roots and rhizomes of Salvia miltiorrhiza Bge. (Danshen in Chinese) are widely used in Chinese herbal medicine. These components from Danshen have significant anti-oxidation properties owing to high levels of tanshinone IIA (TIIA) and salvianolic acid B (Sal B). To make the best use of this natural resource, response surface methodology (RSM) and artificial neural network (ANN) were used for the modeling and optimization of ultrasound-assisted extraction (UAE) of TIIA and Sal B together to determine the antioxidant activity of the extracts obtained from Danshen. In this study, the Box-Behnken design (BBD) was used to improve extraction time (X 1), solvent-to-material ratio (X 2), extraction temperature (X 3), and ethanol concentration (X 4) for the optimal combination of the comprehensive yield of TIIA and Sal B (Y 1) and the antioxidant activity (Y 2). The optimal process parameters were determined to be as follows: extraction time, 73 min; solvent-to-material ratio, 11 mL/g; extraction temperature, 76℃; and ethanol concentration, 80 %. Using these conditions, the predictive optimal combination revealed a comprehensive evaluation value of 16.2281 and an antioxidant activity of 1.1453 mM FeSO 4 /5 g, while the experimental average values for these parameters were determined to be 16.1826 and 1.1415 mM FeSO 4 /5 g, respectively. It was clear that the ANN model had higher accuracy in predictive and optimization capabilities, with higher R2 and lower RMSE, MAE, and relative deviations values, than did RSM. Hence, the ANN model proved to be more effective for the analysis and improvement of the extraction process. [ABSTRACT FROM AUTHOR]