Home About us Contact
|
Home About us Contact | ||
|
|
||
Orthogonal Experiment (orthogonal + experiment)
Selected AbstractsBehavioural interactions between ecosystem engineers control community species richnessECOLOGY LETTERS, Issue 11 2009Paul E. Gribben Abstract Behavioural interactions between ecosystem engineers may strongly influence community structure. We tested whether an invasive ecosystem engineer, the alga Caulerpa taxifolia, indirectly facilitated community diversity by modifying the behaviour of a native ecosystem engineer, the clam Anadara trapezia, in southeastern Australia. In this study, clams in Caulerpa -invaded sediments partially unburied themselves, extending >30% of their shell surface above the sediment, providing rare, hard substrata for colonization. Consequently, clams in Caulerpa had significantly higher diversity and abundance of epibiota compared with clams in unvegetated sediments. To isolate the role of clam burial depth from direct habitat influences or differential predation by habitat, we manipulated clam burial depth, predator exposure and habitat (Caulerpa or unvegetated) in an orthogonal experiment. Burial depth overwhelmingly influenced epibiont species richness and abundance, resulting in a behaviourally mediated facilitation cascade. That Caulerpa controls epibiont communities by altering Anadara burial depths illustrates that even subtle behavioural responses of one ecosystem engineer to another can drive extensive community-wide facilitation. [source] Extraction and Removal of Caffeine from Green Tea by Ultrasonic-Enhanced Supercritical FluidJOURNAL OF FOOD SCIENCE, Issue 4 2010Wei-Qiang Tang ABSTRACT:, Low-caffeine or caffeine-removed tea and its products are widely welcomed on market in recent years. In the present study, we adopt ultrasonic-enhanced supercritical fluid extraction process to remove caffeine from green tea. An orthogonal experiment (L16 (45)) was applied to optimize the best removal conditions. Extraction pressure, extraction time, power of ultrasound, moisture content, and temperature were the main factors to influence the removal rate of caffeine from green tea. The 5 factors chosen for the present investigation were based on the results of a single-factor test. The optimum removal conditions were determined as follows: extraction pressure of 30 MPa, temperature at 55 °C, time of 4 h, 30% moisture content, and ultrasound power of 100 W. Chromatogram and ultraviolet analysis of raw material and decaffeinates suggests that under optimized conditions, the caffeine of green tea was effectively removed and minished without damaging the structure of active ingredients in green tea. [source] Effect of combined photoperiod, water calcium concentration and pH on survival, growth, and moulting of juvenile crayfish (Procambarus clarkii ) cultured under laboratory conditionsAQUACULTURE RESEARCH, Issue 11 2009Cai-Feng Yue Abstract The red swamp crayfish, Procambarus clarkii (Girard), is one of the most commonly farmed freshwater species in inland China due to its high market value and consumer demand. The aim of this study was to determine the optimum combinations of photoperiod, water calcium concentration and pH for juvenile survival, growth and moulting. In our orthogonal experiment, the three environmental factors were varied at three levels (photoperiod: 16L:8D, 12L:12D and 8L:16D; calcium concentration: 45.5, 65.5 and 85.5 mg L,1; and pH: 6.8, 7.8 and 8.8). Range analysis showed that the maximum survival of juvenile crayfish occurred at photoperiods of 16L:8D or 8L:16D, water calcium concentration of 45.5 mg L,1 and pH of 7.8; maximum weight gain at photoperiod 16L:8D, water calcium concentration 65.5 mg L,1 and pH 7.8; maximum length increase at photoperiod 16L:8D, water calcium concentration 65.5 mg L,1 and pH 7.8; and the highest moult frequency at photoperiod 12L:12D, water calcium concentration 65.5 mg L,1 and pH 7.8. Analysis of variance indicated that photoperiod, water calcium concentration and pH significantly influenced only the weight gain of juvenile crayfish (P<0.05). Taking growth into consideration, we suggest that a photoperiod of 16L:8D, calcium concentration of 65.5 mg L,1 and pH 7.8 might be optimal conditions for rearing juvenile P. clarkii. [source] Optimization of metagenomic DNA extraction from activated sludge samplesASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Yuan-Yuan Qu Abstract Metagenomic DNA extraction is essential for metagenomic technology. Therefore, optimization of a conventional total DNA extraction from activated sludge was investigated in detail in this study. Throughout two distinct orthogonal experiments, it was shown that the highest yield for metagenomic DNA could be obtained using TENP buffer, lysozyme of 1 mg ml,1 (1 h), protease K (200 µg ml,1), SDS (1%, 1 h). Furthermore, the quality of the differentially extracted DNA was subsequently assessed by the molecular fingerprint technology, such as denaturing gradient gel electrophoresis (DGGE) and ribosomal intergenic spacer analysis (RISA). The results indicated that the microbial diversity was dramatically different by different combined methods, and the DNA template quality for RISA was much better than that for polymerase chain reaction (PCR)-DGGE. This study provides detail process for metagenomic DNA extraction of activated sludge, and it would be useful for metagenomic DNA extraction of other environment samples. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Preparation and Characterization of Codeposited Palladium-Nickel/Titanium Electrodes and Palladium-Nickel/Polymeric Pyrrole Film/Titanium ElectrodesCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 10 2008X. Hu Abstract Palladium-nickel/titanium (Pd-Ni/Ti) and palladium-nickel/polymeric pyrrole film/titanium (Pd-Ni/PPy/Ti) electrodes were prepared by electrochemical deposition. The electrochemical characteristics of the Pd-Ni/Ti and Pd-Ni/PPy/Ti electrodes were studied by means of cyclic voltammetry (CV) based on orthogonal experiments. CV studies on the electrodes were conducted in 0.5,mol/L sulfuric acid solution. Experimental results indicate that the hydrogen adsorption peak value of the Pd-Ni/PPy/Ti electrode seen at ca. ,500,mV is larger than that of Pd-Ni/Ti electrode. Scanning electron microscope (SEM) images indicate that polymeric pyrrole film, which formed on electrode can modify the electrode surface configuration significantly and provide the surface of the Pd-Ni/PPy/Ti electrode with more layers and a larger surface area. [source] | ||||||||||