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Crassostrea gigas is a commercially important species which is the mostly widely cultured in the world. However, most of the oyster broodstock in China remains unselected. Through a 7-generation of selection on the shell color and growth traits of adult oysters, an excellent strain of C. gigas with black shell coloration and mantle has been developed. In order to facilitate the industrialized breeding, it is necessary to explore the growth performance of the black shell strain in larval stage and find out the optimal conditions for larval development. In this study, the accumulated growth rate and survival rate of the black shell strain and wild population of C. gigas larvae were measured respectively, and a central composite design as well as a response surface method was used to investigate the combined effect of temperature, salinity, and rearing density on the growth of both the two populations. No significant differences were found in survival rate between the two populations, and two model equations for the growth of the two populations were established. The optimizations of accumulated growth rate for two populations were explored. When the temperature, salinity, and rearing density was 25.14 °C, 30.28 psu, and 1.00 ind. ml−1, respectively, the accumulated growth rate for the black shell strain maximized 15.40 μm day−1. With a combination of temperature of 25.06 °C, salinity of 29.27 psu and rearing density of 1.00 ind. ml−1, the maximum value of accumulated growth rate for wild population was 13.20 μm day−1. Furthermore, the larval growth rates were compared between the black shell strain and wild population, and the larvae of the black shell strain significantly grew faster than those of wild population when temperature, salinity and rearing density in a suitable range. [ABSTRACT FROM AUTHOR]

Objective: To optimize the conditions for extraction of quercitrin and total flavonoids (TF) from Herba Polygoni Capitati (Touhualiao in Chinese) by using response surface methodology (RSM). Materials and Methods: A central composite design (CCD) was adopted to investigate the effects of three independent variables including solvent composition (%), solvent-material ratio (ml/g) and extraction time (min) on the responses, quercitrin and TF yields. Results: The optimized conditions of the extraction are as follows: Ethanol concentration, 65.63%; solvent-material ratio, 10.55:1 (ml/g); extraction time, 54.33 min. The established mathematical model described the factors of experimental parameters well and provided a statistically accurate prediction of the optimum yields of quercitrin and TF. Conclusion: The experimental values agreed with those predicted by the established mathematical model, thus indicating the suitability of the model employed and the success of RSM in optimizing the extraction conditions. [ABSTRACT FROM AUTHOR]

Design of Experiments is an effective optimisation methodology. It has been widely used for product and process optimisation design. This paper presents a solution to optimise one of the key quality performances, the isolation of the fused biconical taper wavelength division multiplexer, using Design of Experiments in a communications company in Tianjin, China. The optimum process parameters have been found by response surface optimisation and the isolation has been improved. [ABSTRACT FROM AUTHOR]

A new inulinase-producing strain was isolated from rhizosphere soils of Jerusalem artichoke collected from Shihezi (Xinjiang, China) using Jerusalem artichoke power (JAP) as sole carbon source. It was identified as an Aspergillus niger strain by analysis of 16S rRNA. To improve inulinase production, this fungus was subjected to mutagenesis induced by (60)Co γ-irradiation. A genetically stable mutant (designated E12) was obtained and it showed 2.7-fold higher inulinase activity (128 U/mL) than the parental strain in the supernatant of a submerged culture. Sequential methodology was used to optimize the inulinase production of stain E12. A screening trial was first performed using Plackett-Burman design and variables with statistically significant effects on inulinase bio-production were identified. These significant factors were further optimized by central composite design experiments and response surface methodology. Finally, it was found that the maximum inulinase production (185 U/mL) could be achieved under the optimized conditions namely pH 7.0, yeast extract concentration of 5.0 g/L, JAP concentration of 66.5 g/L, peptone concentration of 29.1 g/L, solution volume of 49.4 mL in 250-mL shake flasks, agitation speed of 180 rpm, and fermentation time of 60 h. The yield of inulinase under optimized culture conditions was approximately 1.4-fold of that obtained by using basal culture medium. These findings are of significance for the potential industrial application of the mutant E12.

An automated aqueous derivatization solid-phase microextraction (SPME) coupled with a gas chromatography/mass spectrometry (GC/MS) method was developed for simultaneous determination of eight pharmaceuticals in water samples. Dimethyl sulfate and tetrabutylammonium hydrogen sulfate were selected as derivatization and activation reagents for the esterification reaction. An experimental design approach, central composition design (CCD), was employed to investigate and optimize the operative factors influencing the extraction efficiency, including extraction time, extraction temperature and ionic strength. The other parameters such as type of fiber coating, pH and derivatization conditions were also evaluated. SPME was finally carried out in headspace mode at 80°C for 60min with the presence of 3.00g Na2SO4, using a home-made 44μm PDMS fiber. Wide linear ranges and low limits of detection (0.06-1.24ng L(-1)) were obtained under the optimized conditions. The relative standard deviations (RSDs) and recoveries ranged from 0.5% to 12.3% and 85% to 110%, respectively. The proposed method was successfully applied to the analysis of the real surface water samples from the Pearl River Estuary., (Copyright © 2015 Elsevier B.V. All rights reserved.)