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41.
Yuan Gao Jun Deng Chunwang Li Fengling Dang Zhuo Liao Zhijun Wu Liguang Li 《Biotechnology advances》2009,27(5):616
We studied the spray characteristics of inedible oil using experimental and simulation methods. Spray penetration, spray cone angle and spray tip speed were measured at different biodiesel ratios in a constant volume vessel with wide visualization and high back pressure, using a high-speed camera. The characteristics of biodiesel spray were simulated under the same conditions using Star-CD software. The experimental results showed that, as the ratio of biodiesel in the blends increased, spray penetration and spray speed increased, but the spray cone angle decreased. Throughout the spray injection period, the region at 0.05–0.475S (spray tip penetration) was a key area affecting spray cone angle. From 0.8 ms after injection, the spray penetration deviation ratios started to increase with increasing biodiesel blend ratios. Simulation results showed similar macroscopic spray characteristics to the experimental results for jatropha oil. The results also showed that the Sauter mean diameter of blend fuels was greater than that of diesel, and spray was more concentrated, due to the higher viscosity and surface tension of the biodiesel, compared with conventional diesel fuel. The macroscopic and microscopic spray properties of blended fuels containing 5%, 10% and 20% biodiesel were similar to diesel. 相似文献
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The baculovirus expression vector system (BEVS) is a popular manufacturing platform for the production of recombinant proteins, antiviral vaccines, gene therapy vectors, and biopesticides. Besides its successful applications in the industrial sector, the system has also played a significant role within the academic community given its extensive use in the production of hard-to-express eukaryotic multiprotein complexes for structural characterization for example. However, as other expression platforms, BEVS has to be continually improved to overcome its limitation and adapt to the constant demand for manufacturing processes that provide recombinant products with improved quality at higher yields and lower production cost.RNA interference, or RNAi, is a relatively recent technology that has revolutionized how scientist study gene function. Originally introduced as a tool to study biological and disease-related processes it has recently been applied to improve the yield and quality of recombinant proteins produced in several expression systems. In this review, we provide a comprehensive summary of the impact that RNAi-mediated silencing of cellular or viral genes in the BEVS has on the production of recombinant products. We also propose a critical analysis of several aspects of the methodologies described in the literature for the use of RNAi technology in the BEVS with the intent to provide the reader with eventually useful guidance for designing experiments. 相似文献
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Christiane Roscher Vicky M. Temperton Michael Scherer-Lorenzen Martin Schmitz Jens Schumacher Bernhard Schmid Nina Buchmann Wolfgang W. Weisser Ernst-Detlef Schulze 《Ecology letters》2005,8(4):419-429
In a large integrated biodiversity project (‘The Jena Experiment’ in Germany) we established two experiments, one with a pool of 60 plant species that ranged broadly from dominant to subordinate competitors on large 20 × 20 m and small 3.5 × 3.5 m plots (= main experiment), and one with a pool of nine potentially dominant species on small 3.5 × 3.5 m plots (= dominance experiment). We found identical positive species richness–aboveground productivity relationships in the main experiment at both scales. This result suggests that scaling up, at least over the short term, is appropriate in interpreting the implications of such experiments for larger‐scale patterns. The species richness–productivity relationship was more pronounced in the experiment with dominant species (46.7 and 82.6% yield increase compared to mean monoculture, respectively). Additionally, transgressive overyielding occurred more frequently in the dominance experiment (67.7% of cases) than in the main experiment (23.4% of cases). Additive partitioning and relative yield total analyses showed that both complementarity and selection effects contributed to the positive net biodiversity effect. 相似文献
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Studies of the wild grass Anthoxanthum odoratum at the long‐term Park Grass Experiment (PGE, Harpenden, UK) document a well‐known example of rapid plant evolution in response to environmental change. Repeated fertilizer applications have acidified the soil in some experimental plots over the past 150+ years, and Anthoxanthum subpopulations have quickly become locally adapted. Early reciprocal transplants showed subpopulation differentiation specifically in response to soil aluminium (Al) toxicity across the experiment, even at small (30 m) spatial scales. Almost 40 years after its original measurement, we reassessed the degree of local adaptation to soil Al at the PGE using updated phenotyping methods and identified genes with variation linked to the tolerance trait. Root growth assays show that plants are locally adapted to soil Al at both the seedling and adult growth stages, but to a smaller extent than previously inferred. Among a large suite of candidate loci that were previously shown to have Al‐sensitive expression differences between sensitive and tolerant plants, three loci contained SNPs that are associated with both Al tolerance and soil acidity: an Al‐sensitive malate transporter (ALMT), a tonoplast intrinsic protein (TIP) and the putative homolog of the rice cell‐wall modification gene STAR1. Natural genetic variation at these loci is likely to have contributed to the recent rapid evolution at PGE. Continued study of Al tolerance variants in Anthoxanthum will allow us to test hypotheses about the nature and source of genetic variation that enables some species to adapt to soil acidification and other types of rapid environmental change. 相似文献
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《Journal of biological education》2012,46(4):420-440
The observation of living animals in school laboratories provides authentic views of biological research. Various studies stress the importance of primary experiences in biology classes. However, educational films may serve as an alternative in some cases. The aim of this study was to investigate student motivation before and after treatments, including (1) an educational film, (2) a hands-on activity with living animals accompanied by an educational film and (3) a hands-on activity with living animals. We investigated the influence of teaching method, gender and class level on student motivation and learning enjoyment. In all treatments, Temnothorax ants were addressed, which can be easily kept and observed. This paper is within the scope of a longitudinal project based on the concept of ‘ant research’ in class. Students (N = 140) from six classes (lower and intermediate secondary school levels) participated in the study. Student motivation was measured using a two-stage test design, including a standardised questionnaire on current motivation and a test on learning enjoyment. The findings of this study suggest that the younger students prefer hands-on activities, while students at an intermediate secondary school level are more interested in video-based learning. Since the combination of hands-on activity and video yielded the best results, the potential of using videos as facilitators for hands-on learning is discussed. 相似文献
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Jan Pinowski Andrzej Haman Leszek Jerzak Barbara Pinowska Miłosława Barkowska Andrzej Grodzki Krzysztof Haman 《Journal of thermal biology》2006
Using an electronic apparatus simulating a bird roosting in a nest at night, we examined the insulating qualities of Eurasian Tree Sparrow (Passer montanus) nests built in nest boxes under winter conditions. Nests of different construction were compared with an empty box, and with roosting in open air. Energy savings in an empty box accounted for 18%, in boxes with incomplete nests for 23% and in boxes with complete nests up to 36%. The insulating value of nests mostly depended on their completeness and the proportion of feathers in the lining. 相似文献
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