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排序方式: 共有243条查询结果,搜索用时 15 毫秒
1.
A. Vandelannoote H. Robberecht H. Deelstra F. Vyumvuhore L. Bitetera F. Ollevier 《Hydrobiologia》1996,328(2):161-171
Sources of pollution at the north end of Lake Tanganyika are concentrated around Bujumbura, Burundi. The impact of River Ntahangwa on the water quality of this part of Lake Tanganyika was compared with that of an unpolluted river, the Mugere. A shallow bay, not influenced by a river, was used as a reference station. Chemical analyses were carried out at four week intervals during nearly a year. Samples were taken at different distances from the shore and at different depths. River impact was detected up to 100 m from both river mouths. Even at 50 m from the mouth of the polluted River Ntahangwa, no important decrease of dissolved oxygen was detected. Chlorophyll-a maxima were found 100 m from the Ntahangwa mouth, but this was also the case 100 m from shore in the unpolluted bay. Lake water at 60 m depth was saturated with oxygen during the dry season, as it used to be in 1956. The rivers studied descent initially within the lake due to greater sediment load and lower water temperature. Nevertheless, it appears that these rivers mix completely in the lake within 100–300 m from the river mouths. The direct effects from organic pollution of the Ntahangwa on the lake seem to be rather negligible. Appropriate anti-erosion measures should reduce massive sediment discharge into the lake. 相似文献
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S. Vervarcke O. Lescroart F. Ollevier R. Kinget A. Michoel 《Zeitschrift fur angewandte Ichthyologie》2004,20(2):134-138
The aim of this study was to investigate the success of oral vaccination application in African catfish using Vibrio anguillarum O2 bacterins. The antigen uptake was followed by competitive enzyme‐linked immunosorbent assay (ELISA). Serum antibody response was measured using an indirect ELISA. Several in vivo administration methods were investigated. Intraperitoneal injection gave the highest absorption rate, with high antibody levels in the systemic circulation. Oral intubation of bacterin‐layered pellets resulted in low antigen uptake and low antibody levels. The addition of absorption enhancers increased the serum antigen levels. An enteric coating applied on the pellets containing vaccine did not improve the immune response. 相似文献
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D’Hont Anouk Gittenberger Adriaan Hendriks A. Jan Leuven Rob S. E. W. 《Biological invasions》2021,23(7):2125-2141
Biological Invasions - Ponto-Caspian dreissenids are notorious freshwater invaders. Recently, widespread observations show a dominance shift from the early invader, Dreissena polymorpha, to its... 相似文献
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Kathleen D'Halluin Chantal Vanderstraeten Jolien Van Hulle Joanna Rosolowska Ilse Van Den Brande Anouk Pennewaert Kristel D'Hont Martine Bossut Derek Jantz Rene Ruiter Jean Broadhvest 《Plant biotechnology journal》2013,11(8):933-941
Recent developments of tools for targeted genome modification have led to new concepts in how multiple traits can be combined. Targeted genome modification is based on the use of nucleases with tailor‐made specificities to introduce a DNA double‐strand break (DSB) at specific target loci. A re‐engineered meganuclease was designed for specific cleavage of an endogenous target sequence adjacent to a transgenic insect control locus in cotton. The combination of targeted DNA cleavage and homologous recombination–mediated repair made precise targeted insertion of additional trait genes (hppd, epsps) feasible in cotton. Targeted insertion events were recovered at a frequency of about 2% of the independently transformed embryogenic callus lines. We further demonstrated that all trait genes were inherited as a single genetic unit, which will simplify future multiple‐trait introgression. 相似文献
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Julia D. I. Meuwese Anouk M. van Loon H. Steven Scholte Philipp B. Lirk Nienke C. C. Vulink Markus W. Hollmann Victor A. F. Lamme 《PloS one》2013,8(11)
Recurrent interactions between neurons in the visual cortex are crucial for the integration of image elements into coherent objects, such as in figure-ground segregation of textured images. Blocking N-methyl-D-aspartate (NMDA) receptors in monkeys can abolish neural signals related to figure-ground segregation and feature integration. However, it is unknown whether this also affects perceptual integration itself. Therefore, we tested whether ketamine, a non-competitive NMDA receptor antagonist, reduces feature integration in humans. We administered a subanesthetic dose of ketamine to healthy subjects who performed a texture discrimination task in a placebo-controlled double blind within-subject design. We found that ketamine significantly impaired performance on the texture discrimination task compared to the placebo condition, while performance on a control fixation task was much less impaired. This effect is not merely due to task difficulty or a difference in sedation levels. We are the first to show a behavioral effect on feature integration by manipulating the NMDA receptor in humans. 相似文献
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Ruth Muchekehu Dingguo Liu Mark Horn Lioudmila Campbell Joselyn Del Rosario Michael Bacica Haim Moskowitz Trina Osothprarop Anouk Dirksen Venkata Doppalapudi Allan Kaspar Steven R. Pirie-Shepherd Julia Coronella 《Translational oncology》2013,6(5):562-IN6
Poor drug delivery and penetration of antibody-mediated therapies pose significant obstacles to effective treatment of solid tumors. This study explored the role of pharmacokinetics, valency, and molecular weight in maximizing drug delivery. Biodistribution of a fibroblast growth factor receptor 4 (FGFR4) targeting CovX-body (an FGFR4-binding peptide covalently linked to a nontargeting IgG scaffold; 150 kDa) and enzymatically generated FGFR4 targeting F(ab)2 (100 kDa) and Fab (50 kDa) fragments was measured. Peak tumor levels were achieved in 1 to 2 hours for Fab and F(ab)2versus 8 hours for IgG, and the percentage injected dose in tumors was 0.45%, 0.5%, and 2.5%, respectively, compared to 0.3%, 2%, and 6% of their nontargeting controls. To explore the contribution of multivalent binding, homodimeric peptides were conjugated to the different sized scaffolds, creating FGFR4 targeting IgG and F(ab)2 with four peptides and Fab with two peptides. Increased valency resulted in an increase in cell surface binding of the bivalent constructs. There was an inverse relationship between valency and intratumoral drug concentration, consistent with targeted consumption. Immunohistochemical analysis demonstrated increased size and increased cell binding decreased tumor penetration. The binding site barrier hypothesis suggests that limited tumor penetration, as a result of high-affinity binding, could result in decreased efficacy. In our studies, increased target binding translated into superior efficacy of the IgG instead, because of superior inhibition of FGFR4 proliferation pathways and dosing through the binding site barrier. Increasing valency is therefore an effective way to increase the efficacy of antibody-based drugs. 相似文献
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Maud Martin Ilse Geudens Jonathan Bruyr Michael Potente Anouk Bleuart Marielle Lebrun Nicolas Simonis Christophe Deroanne Jean‐Claude Twizere Philippe Soubeyran Paul Peixoto Denis Mottet Veerle Janssens Wolf‐Karsten Hofmann Filip Claes Peter Carmeliet Richard Kettmann Holger Gerhardt Franck Dequiedt 《The EMBO journal》2013,32(18):2491-2503