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排序方式: 共有123条查询结果,搜索用时 46 毫秒
21.
Flocculation of microalgae using cationic starch 总被引:2,自引:0,他引:2
Dries Vandamme Imogen Foubert Boudewijn Meesschaert Koenraad Muylaert 《Journal of applied phycology》2010,22(4):525-530
Due to their small size and low concentration in the culture medium, cost-efficient harvesting of microalgae is a major challenge.
We evaluated the potential of cationic starch as a flocculant for harvesting microalgae using jar test experiments. Cationic
starch was an efficient flocculant for freshwater (Parachlorella, Scenedesmus) but not for marine microalgae (Phaeodactylum, Nannochloropsis). At high cationic starch doses, dispersion restabilization was observed. The required cationic starch dose to induce flocculation
increased linearly with the initial algal biomass concentration. Of the two commercial cationic starch flocculants tested,
Greenfloc 120 (used in wastewater treatment) was more efficient than Cargill C*Bond HR 35.849 (used in paper manufacturing).
For flocculation of Parachlorella using Greenfloc 120, the cationic starch to algal biomass ratio required to flocculate 80% of algal biomass was 0.1. For
Scenedesmus, a lower dose was required (ratio 0.03). Flocculation of Parachlorella using Greenfloc 120 was independent of pH in the pH range of 5 to 10. Measurements of the maximum quantum yield of PSII suggest
that Greenfloc 120 cationic starch was not toxic to Parachlorella. Cationic starch may be used as an efficient, nontoxic, cost-effective, and widely available flocculant for harvesting microalgal
biomass. 相似文献
22.
Koenraad Kortmulder 《Acta biotheoretica》1998,46(1):53-63
Displacement acts, once a hot topic in ethology, but wrapped in silence for two decades since, have recently been suggested to indicate and relax social tension (Maestripieri et al., 1992; Wiepkema, 1987). The first of these contentions seems to be in contradiction with some of the classical ethological studies of displacement behaviour, in particular those supporting the disinhibition hypothesis, since the latter would not predict any positive correlation between amount of tension (i.c. intensity of the conflict) and the occurrence of displacement acts.A critical examination of these studies reveals that a positive correlation of the sort has been found, but that proponents of the disinhibition hypothesis tried to explain it in terms of their own model, rather than taking it at its face value. (The reason for this is that they viewed it as pleading for the surplus hypothesis which they rejected). It can be shown that at least some of their explanations are grounded on assumptions which are arbitrary. Also, the disinhibition hypothesis does not account for the occurrence of displacement behaviour in contexts with tension but without conflict.This discussion leads to a new interpretation of displacement behaviour, in which tension is the direct cause, whether generated by conflict or otherwise, and relaxation is brought about by a breaking of the cognitive symmetry between actors. It is indicated how this interpretation may be tested with experiments. 相似文献
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24.
Isabella Muylaert Zhiyuan Zhao Per Elias 《The Journal of biological chemistry》2014,289(47):32583-32592
Herpes simplex virus 1 (HSV-1) UL5/8/52 helicase-primase complex is required for DNA unwinding at the replication fork and synthesis of primers during virus replication, and it has become a promising novel target for antiviral therapy. Using molecular cloning, we have identified three separate domains of UL52. Co-immunoprecipitation experiments in extracts from cells transiently expressing HA-tagged UL5, FLAG-UL8, and enhanced GFP-tagged UL52 domains revealed that the N-terminal domain of UL52 primase binds UL5 helicase and the middle domain interacts with the UL8 accessory protein. In addition, an interaction between the single strand DNA-binding protein ICP8 and the UL52 middle domain was observed. The complex between UL5 and UL52 was stabilized by the antiviral compound BAY 54-6322, and mutations providing resistance to the drug obliterate this effect. Our results also suggest a mechanism for accommodating conformational strain resulting from movement of UL5 and UL52 in opposite directions on the lagging strand template, and they identify molecular complexes that can be further examined by structural biology techniques to resolve the mechanism of primer synthesis during herpesvirus replication. Finally, they help to explain the mechanism of action of a novel class of antiviral compounds currently being evaluated in clinical trials. 相似文献
25.
Janneke H.M. Schuurs-Hoeijmakers Edwin C. Oh Lisenka E.L.M. Vissers Mariëlle E.M. Swinkels Christian Gilissen Michèl A. Willemsen Maureen Holvoet Marloes Steehouwer Joris A. Veltman Bert B.A. de Vries Hans van Bokhoven Arjan P.M. de Brouwer Nicholas Katsanis Koenraad Devriendt Han G. Brunner 《American journal of human genetics》2012
26.
27.
Eline Ryckebosch Sara Paulina Cuéllar Bermúdez Romina Termote-Verhalle Charlotte Bruneel Koenraad Muylaert Roberto Parra-Saldivar Imogen Foubert 《Journal of applied phycology》2014,26(3):1501-1510
Microalgae oils are considered to be promising alternative sources of omega-3 LC-PUFA. The aim of this work was therefore to evaluate different solvent (mixtures), currently accepted for use in the food industry, for the extraction of lipids from Nannochloropsis gaditana, an omega-3 LC-PUFA-rich microalga. Importantly, not only the total lipid yield but also the lipid class, eicosapentaenoic acid, carotenoid, and sterol yield were investigated. It was shown that the highest yield for each of the components was obtained with dichloromethane/ethanol (1:1). All extracts except the one obtained with dichloromethane/ethanol (1:1) were enriched in neutral lipids and depleted in polar lipids, when compared to the total lipid extract (chloroform/methanol 1:1). Hexane/isopropanol (3:2) seems to be the second best option: it has the advantage of performing better at criteria such as toxicity, but has the disadvantage that almost half of the interesting oil cannot be recovered. 相似文献
28.
Impact of land-use intensity on the conservation of functional and phylogenetic diversity in temperate semi-natural plant communities 总被引:1,自引:0,他引:1
The earth is facing a worldwide decline in biodiversity, with land-use change identified as one of the most important drivers. There is evidence that the loss of diversity has a significant impact on ecosystem functioning. Earlier research focused on species richness, but more recent, functional and phylogenetic diversity came into the picture as the stronger determinants of ecosystem processes. The effects of increasing land-use intensity on functional (FD) and phylogenetic diversity (PD), however, are still poorly understood. We studied how FD and PD are affected by land-use intensity in temperate plant communities. Our results show that land-use intensity has a clear impact on species richness, but also affects functional and phylogenetic diversity. Intensive agricultural areas fail to support high and sustainable levels of functional and phylogenetic diversity. These results highlight the need for the protection of biodiversity in nature reserves and the conservation of areas with extensive agricultural practices. Because species richness may influence the measures of functional and phylogenetic diversity, we compared the observed FD and PD values with random values generated with a matrix-swap null model. The observed discrepancy between species loss and the loss of FD and PD calls for an integrated approach to biodiversity conservation, in which the different components of biodiversity are considered together. 相似文献
29.
Christof J Majoor Marianne A van de Pol Pieter Willem Kamphuisen Joost CM Meijers Richard Molenkamp Katja C Wolthers Tom van der Poll Rienk Nieuwland Sebastian L Johnston Peter J Sterk Elisabeth HD Bel Rene Lutter Koenraad F van der Sluijs 《Respiratory research》2014,15(1):14