排序方式: 共有30条查询结果,搜索用时 15 毫秒
1.
Signe M. Andersen Jonas Teilmann Rune Dietz Niels M. Schmidt Lee A. Miller 《水产资源保护:海洋与淡水生态系统》2014,24(5):712-723
- The response of individual harbour seals (Phoca vitulina) to controlled and sporadic disturbances when hauled out in the Anholt seal reserve, Denmark, was studied. Sporadic disturbances from pedestrians, boats, low‐flying aeroplanes and grey seals (Halichoerus grypus) were observed in or near the reserve. VHF and satellite transmitters were attached to eight harbour seals to determine post‐disturbance and undisturbed behaviour during the pre‐breeding period (25 April to 21 May 2008).
- Both disturbed and undisturbed seals mostly returned to the haul‐out site from dusk and throughout the night. Only pedestrian disturbances caused significantly longer‐lasting trips at sea than undisturbed trips, while the other types of disturbance did not affect trip duration. The general maximum extent and area‐use of disturbed and undisturbed trips were comparable and almost all at‐sea locations were within 40 km from the haul‐out site. The maximum extent of post‐disturbance trips, however, varied among individuals and disturbance types, and was strongly correlated with the duration of trips.
- Disturbed and undisturbed seals used the same areas, suggesting that these areas represent normal foraging areas. This may indicate that harbour seals reduce the cost of being disturbed by foraging after disturbances instead of waiting close to the haul‐out site to resume hauling out.
- During the pre‐breeding period the seals showed a very high site fidelity by consistently returning to the same haul‐out site, even when subjected to repeated disturbances.
2.
3.
Signe J. Plunkett D.V.M. 《Journal of Veterinary Emergency and Critical Care》2000,10(3):169-171
There is an increasing incidence of anaphylactic reactions in cats due to the administration of ophthalmic bacitracin, neomycin, polymyxin medications. Most of the reported cases have been fatal. This is the report of a cat that survived the initial episode only to develop renal failure and cardiomyopathy. This lead to euthanasia seven days later. Dr. Kathryn Meyer of the U.S. Pharmacopeia and Dr. Signe Plunkett of the Emergency Animal Clinic in Phoenix are conducting an ongoing study, and they are interested in the reports of any additional cases. 相似文献
4.
Analytical validation of a flow cytometric protocol for quantification of platelet microparticles in dogs 下载免费PDF全文
5.
Fanlu Wang Yuejun Xiao Sandesh Neupane Signe Helle Ptak Ramona Rmer Junyu Xiong Julia Ohmes Andreas Seekamp Xavier Frett Susanne Alban Sabine Fuchs 《Marine drugs》2021,19(4)
Fucoidans, sulfated polysaccharides extracted from brown algae, are marine products with the potential to modulate bone formation and vascularization processes. The bioactivity and safety of fucoidans are highly associated with their chemical structure, which may vary with algae species and extraction method. Thus, in depth evaluation of fucoidan extracts in terms of endotoxin content, cytotoxicity, and their detailed molecular biological impact on the individual cell types in bone is needed. In this study, we characterized fucoidan extracts from three different Fucus species including Fucus vesiculosus (Fv), Fucus serratus (Fs), and Fucus distichus subsp. evanescens (Fe) for their chemical features, endotoxin content, cytotoxicity, and bioactive effects on human outgrowth endothelial cells (OEC) and human mesenchymal stem cells (MSC) as in vitro models for bone function and vascularization. Extracts contained mainly high molecular weight (HMW) fucoidans and were free of endotoxins that may cause inflammation or influence vascularization. OEC tolerated fucoidan concentrations up to 200 µg/mL, and no indication of cytotoxicity was observed. The inflammatory response, however, investigated by real-time PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) and endothelial barrier assessed by impedance measurement differed for the individual extracts. MSC in comparison with endothelial cells were more sensitive to fucoidans and showed partly reduced metabolic activity and proliferation at higher doses of fucoidans. Further results for MSC indicated impaired osteogenic functions in alkaline phosphatase and calcification assays. All tested extracts consistently lowered important molecular mediators involved in angiogenesis, such a VEGF (vascular endothelial growth factor), ANG-1 (angiopoietin 1), and ANG-2 (angiopoietin 2), as indicated by RT-PCR and ELISA. This was associated with antiangiogenic effects at the functional level using selected extracts in co-culture models to mimic bone vascularization processes during bone regeneration or osteosarcoma. 相似文献
6.
Spatial scaling of wildland fuels for six forest and rangeland ecosystems of the northern Rocky Mountains, USA 总被引:1,自引:1,他引:0
Robert E. Keane Kathy Gray Valentina Bacciu Signe Leirfallom 《Landscape Ecology》2012,27(8):1213-1234
Wildland fuels are important to fire managers because they can be manipulated to achieve management goals, such as restoring ecosystems, decreasing fire intensity, minimizing plant mortality, and reducing erosion. However, it is difficult to accurately measure, describe, and map wildland fuels because of the great variability of wildland fuelbed properties over space and time. Few have quantified the scale of this variability across space to understand its effect on fire spread, burning intensity, and ecological effects. This study investigated the spatial variability of loading (biomass) across major surface and canopy fuel components in low elevation northern Rocky Mountain forest and rangeland ecosystems to determine the inherent scale of surface fuel and canopy fuel distributions. Biomass loadings (kg?m?2) were measured for seven surface fuel components??four downed dead woody fuel size classes (0?C6?mm, 6?C25?mm, 25?C75?mm, and 75?+?mm), duff plus litter, shrub, and herb??using a spatially nested plot sampling design within a 1?km2 square sampling grid installed at six sites in the northern US Rocky Mountains. Bulk density, biomass, and cover of the forest canopy were also measured for each plot in the grid. Surface fuel loadings were estimated using a combination of photoload and destructive collection methods at many distances within the grid. We quantified spatial variability of fuel component loading using spatial variograms, and found that each fuel component had its own inherent scale with fine fuels varying at scales of 1?C5?m, coarse fuels at 10?C150?m, and canopy fuels from 100 to 500?m. Using regression analyses, we computed a scaling factor of 4.6?m for fuel particle diameter (4.6?m increase in scale with each cm increase in particle diameter). Findings from this study can be used to design fuel sampling projects, classify fuelbeds, and map fuel characteristics, such as loading, to account for the inherent scale of fuel distributions to get more accurate fuel loading estimations. 相似文献
7.
Mogens Vestergaard Kristen Sejrsen John Foldager Signe Klastrup Dale E. Bauman 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(3):165-172
Abstract Our objective was to examine the effects of bovine growth hormone (bGH) on growth, carcass composition and meat quality of dairy heifers. Nine monozygotic twin pairs of Friesian or Red Danish cattle were used, and pair-fed à diet consisting of grass silage, barley and soybean meal. Within each pair, one animal was given daily subcutaneous injections of 20 IU of pituitary-derived bGH (15–20 mg), while the other animal was injected with saline (excipient). Treatments started at 179±2 kg body weight and lasted for 15.6 weeks. At slaughter, carcass composition and meat quality were analyzed. bGH treatment increased gain by 8% (948 vs. 877 g/d; P <0.03). The amount of saleable meat in carcass and lean content of four main carcass cuts were on average increased by 2% (P <0.05). Concomitantly, carcass fat trim was reduced by 12% (P <0.001), fat trim of individual cuts by 4–21% (P <0.05), and kidney fat by 13% (P <0.01). Except for a 20% reduction of intramuscular fat content (P <0.001), meat quality assessed by objective as well as subjective methods was unaffected by bGH treatment. In summary, bGH treatment of dairy heifers around puberty stimulated growth and reduced carcass fattening including intramuscular fat, while eating quality of the meat was unaffected. 相似文献
8.
Hoff S Lund MN Petersen MA Jespersen BM Andersen ML 《Journal of agricultural and food chemistry》2012,60(22):5652-5659
Influence of malt roasting on the oxidative stability of sweet wort was evaluated based on radical intensity, volatile profile, content of transition metals (Fe and Cu) and thiols. Malt roasting had a large influence on the oxidative stability of sweet wort. Light sweet worts were more stable with low radical intensity, low Fe content, and ability to retain volatile compounds when heated. At mild roasting, the Fe content in the wort increased but remained close to constant with further roasting. Dark sweet worts were less stable with high radical intensities, high Fe content, and a decreased ability to retain volatiles. Results suggested that the Maillard reaction compounds formed during the roasting of malt are prooxidants in sweet wort. A thiol-removing capacity was observed in sweet wort, and it was gradually inhibited by malt roasting. It is possibly caused by thiol oxidizing enzymes present in the fresh malt. 相似文献
9.
The underlying mechanisms governing nonenzymatic pectin and pectate degradation during thermal treatment have not yet been fully elucidated. This study determined the extent of nonenzymatic degradation due to beta-elimination, acid hydrolysis, and demethylation during prolonged heating of citrus pectins and its influence on physicochemical properties. Solutions of citrus pectins, buffered from pH 4.0 to 8.5, were heated at 75, 85, 95, and 110 degrees C for 0-300 min. Evolution of methanol and formation of reducing groups and unsaturated uronides were monitored during heating. Molecular weight and viscosity changes were determined through size exclusion chromatography and capillary viscometry, respectively. Results showed that at pH 4.5, the activation energies of acid hydrolysis, beta-elimination, and demethylation are 95, 136, and 98 kJ/mol, respectively. This means that at this pH, acid hydrolysis occurs more rapidly than beta-elimination. Furthermore, the rate of acid hydrolysis is diminished by higher levels of methyl esterification. Also, citrus pectin (93% esterified) degrades primarily via beta-elimination even under acidic conditions. Acid hydrolysis and beta-elimination caused significant reduction in relative viscosity and molecular weight. 相似文献
10.
Concentrating tomato juice to paste during the tomato season allows for preservation and long-term storage, but subsequent dilution for formulation of value-added products is known to result in a loss of consistency. To understand the reasons for this, samples of unconcentrated juice, processing intermediates, and concentrated paste were collected from an industrial processing plant during normal commercial production. All samples were diluted with water to 5 degrees Brix and then analyzed for consistency and pectin content. Whole juice consistency, measured with a Bostwick consistometer, decreased through the course of juice concentration, with the largest change occurring early in the process, as the juice was concentrated from 5 to 10 degrees Brix. This decrease in consistency occurred during the production of paste from both hot- and cold-break juices. The change in Bostwick value was correlated with a decrease in the precipitate weight ratio. The loss of consistency during commercial processing was not the direct result of water removal because a sample of this same 5 degrees Brix juice could be concentrated 2-fold in a vacuum oven and then diluted back to 5 degrees Brix with no change in consistency or precipitate ratio. Total pectin content did not change as the juice was concentrated to paste, but the proportion of the total pectin that was water soluble increased. The greatest increases in pectin solubility occurred during the hot break and late in the process where the evaporator temperature was the highest. 相似文献