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51.
Pedersen HC Fossøy F Kålås JA Lierhagen S 《The Science of the total environment》2006,371(1-3):176-189
A circumpolar survey of heavy metals in willow ptarmigan liver and kidney revealed considerable variations in Cd content in Canada and Scandinavia. The Cd content in central Canada was comparable with that in Scandinavia and Russia, at least for kidney. However, in both liver and kidney the median for Canada as a whole was much higher than in the other countries. Some Canadian locations had exceptionally high levels, several birds having >50 mg kg(-1) in liver and >400 mg kg(-1) in kidney. In Norway, the Cd content was highest in central mountain areas in south Norway and inland locations in the two northernmost counties. Five locations in central and north Norway showed mean Cd levels in kidney above 100 mg kg(-1). It is difficult to evaluate regional differences in Sweden, but most locations had the same Cd level as moderately contaminated locations in Norway. Cd levels in Russia were comparable to moderately contaminated locations in the other countries. Due to a high intake of willow, naturally rich in Cd, direct comparison of the Cd level in willow ptarmigan from different locations cannot reveal the effects of long-range pollution. The Pb concentration in willow ptarmigan kidney and liver varied significantly in Norway and Canada, but not in Sweden and Russia. Levels in Sweden and Russia were comparable to those in Canada and low levels in Norway. The highest median value from all locations within countries was found in Norway, both in liver and kidney. The highest Pb content was found in south Norway, indicating an effect of long-range pollution in willow ptarmigan. The level in western Canada was significantly higher than in central Canada. The Hg content in liver varied significantly from one location to another in all the countries and in kidney everywhere except Sweden. In Scandinavia, there is no distinct regional pattern. Canada had a significantly higher Hg level in central than western regions in both tissues the opposite of that found for Cd and Pb. Cu and Zn showed significant variations from one location to another in liver and kidney in Canada and Norway, but only in kidney in samples from Sweden. Comparison between western and central Canada revealed a significant difference for Cu in liver, samples from central Canada having more. There are no significant differences from one country to another, but some localities in Canada seem to have higher Cu concentrations in kidney than are found in Scandinavia and Russia. 相似文献
52.
G. Sørensen A.L. Nielsen Morten Møller Pedersen S. Poulsen H. Nissen M. Poulsen S.D. Nygaard 《Progress in Organic Coatings》2010
Porous microparticles represent an attractive encapsulation platform as they provide a feasible route to a wide range of encapsulated chemical compounds. This assures an increased lifetime of the encapsulated compound by protecting it from the surrounding environment as well as providing a way to control the release rate. Porous microparticles encapsulating the commonly used biocide for wood protection, 3-iodoprop-2-ynyl N-butylcarbamate (IPBC), have been synthesized. The microparticles are spherical with an average size distribution of roughly 1 μm as determined by scanning electron microscopy (SEM). Determination of the release rate of the biocide from microcapsules incorporated into the paint film has been performed under diluted conditions. These experiments show that a slower release of the biocide can be obtained by encapsulation. Additionally, the microparticles have been shown to prolong the biocidal effect of the fungicide under accelerated weathering tests by protecting the biocide from UV-induced chemical degradation. 相似文献
53.
G.C.Pedersen J.E.Eldridge 《硫酸工业》2009,(4):21-26
介绍Kimre公司的SXF^TM半错流洗涤器的结构、优点和应用。该洗涤器采用卧式并流气液接触方式,可根据需要分隔成不同操作段,在由交织单丝构成的纤维介质上完成气体的冷却、净化和除沫。与传统立式逆流填料塔相比,该洗涤器的优点为:高度低,泵、阀门、控制器等可在地面安装,容易操作和维修;液气比范围宽;可进行多级操作,包括在一台设备内完成多个化学过程。如用于冶炼烟气净化,所有步骤可在一台设备内完成。列举了化肥厂造粒塔气体净化、磷酸厂气体除氟和硫酸厂干燥塔除沫等应用实例。 相似文献
54.
Torben?H.?R?nne Lars?S.?Pedersen Xuebing?XuEmail author 《Journal of the American Oil Chemists' Society》2005,82(10):737-743
The triglyceride (fatty acid) selectivity of an immobilized lipase from Thermomyces lanuginosa (Lipozyme TL IM) was investigated in lipase-catalyzed interesterification reactions between two nono-acid TG in n-hexane. Tristearin (tri-C18∶0) was used as a reference in a series of TG with saturated FA from tri-C4∶0 to tri-C20∶0, except
for tri-C6∶0, and in a series of unsaturated FA from tri-C18∶1 to tri-C18∶3. The quantification was performed by HPLC, and
different methods of selectivity evaluation were used. None of the methods used showed any significant differences between
the performances of the lipase on the different TG, indicating that Lipozyme TL IM is nonselective toward FA or TG in the
system used. A response surface design was used to investigate the influence of water activities (a
w
) and reaction temperatures on the reactivity of Lipozyme TL IM with a system of tripalmitin (tri-C16∶0) and trilaurin (tri-C12∶0)
in n-hexane. An increase in temperature (40 to 60°C) was found to affect the reactivity of the lipase significantly. The reactivity
of Lipozyme TL IM was unaffected by the change in a
w
from 0.1130 to 0.5289. An increase in a
w
only led to an increase in FFA formation. 相似文献
55.
56.
O. B. Jrgensen L. G. Karlsen N. B. Nielsen S. Pedersen Susanne Rugh 《Starch - St?rke》1988,40(8):307-313
The properties of a new immobilized glucose isomerase, produced by a selected strain of Streptomyces murinus, are described. The major advantages of the new immobilized enzyme are a productivity of more than 10,000 kg syrup dry substance per kg enzyme under optimal industrial conditions, increased activity and a very low syrup by-product formation. The influence of process parameters (temperature, pH and feed syrup additives) on activity and stability is discussed based on laboratory and industrial plant data. 相似文献
57.
Mette B. Petersen Jeanette Pedersen Dinah L. Holm Matthew Denwood Liza R. Nielsen 《Journal of dairy science》2018,101(8):7383-7396
Mycoplasma bovis is an important pathogen causing disease and substantial economic losses in cattle. However, knowledge of the dynamics of antibody responses in individual cows in the face of an outbreak is currently extremely limited. The use of commercial antibody tests to support clinical decision-making and for surveillance purposes is therefore challenging. Our objective was to describe the dynamics of M. bovis antibody responses in 4 Danish dairy herds experiencing an acute outbreak of M. bovis-associated disease, and to compare the antibody dynamics between dairy cows with different disease manifestations. A total of 120 cows were examined using a standardized clinical protocol and categorized into 4 disease groups: “mastitis,” “systemic,” “nonspecific,” and “none.” Paired blood and milk samples were collected and tested using a commercial M. bovis antibody–detecting ELISA. Plots of raw data and generalized additive mixed models with cow and herd as random effects were used to describe serum and milk antibody dynamics relative to the estimated time of onset of clinical disease. Cows with mastitis had high optical density measurement (ODC%) of antibodies in both milk and serum at disease onset. The estimated mean ODC% in milk was below the manufacturer's cut-off for the other groups for the entire study period. The estimated mean serum ODC% in the “systemic” group was high at onset of disease and stayed above the cut-off until 65 d after disease onset. However, the lower 95% confidence interval (CI) for the mean ODC% was only above the manufacturer's cut-off between 7 and 17 d after onset of disease. The CI of the “systemic” and “none” groups did not overlap at any time between the day of disease onset and 65 d after disease onset, and the estimated mean ODC% for both the “nonspecific” and “none” groups were generally below the cut-off for the majority of the study period. In conclusion, the serum antibody responses were highly dynamic and showed a high level of variation between individual cows. This strongly suggests that serology is unlikely to be useful for individual diagnosis of M. bovis-associated disease in dairy cows. However, it might still be useful for herd- or group-level diagnosis. Antibodies in milk were only increased in cows with M. bovis mastitis, indicating that milk antibody measurements only have diagnostic utility for cows with mastitis. 相似文献
58.
<正>KPF设计师事务所已完成了Two Kingdom Street项目设计。该项目投资8800万英镑,由Development Securities公司开发,为Aviva Investors公司和Quinlan Private公司所有。该项目提供了2.2万m2的最佳办公空间,是帕丁顿中心项目第二阶段的最新增加项目,位于帕丁顿火车站附近的大型综合开发区内。 相似文献
59.
Jacob W. Schmidt Anders Bennitz Bj?rn T?ljsten Henning Pedersen 《Canadian Metallurgical Quarterly》2010,14(4):397-405
A durable and very efficient external strengthening system is achieved if steel tendons for posttensioning applications can be replaced with carbon fiber-reinforced polymer (CFRP) tendons, and if reliable anchorage systems are developed. This paper presents a newly developed and simple-to-use, two-piece wedge anchorage for CFRP tendons with an integrated sleeve and a differential angle between barrel and wedge sections. Three longitudinal slits are cut into the one-piece wedge, with one slit open and the other two stopping 1 mm from the inner wedge hole. The integrated sleeve holds the wedge’s sections together during presetting and loading, resulting in a circumferential confined gripping of the CFRP tendon and optimized surface friction area. Therefore, the one-piece wedge differs from conventional wedge systems, where the wedges act separately with adjacent spaces, wedging the separate tendon sleeve in the longitudinal direction. Evaluation of the failure modes during testing was one of the main keys in achieving an increasingly better performance of the anchorage until the final anchorage was developed. The obtained failure modes are therefore described to enlighten the importance of addressing them when testing. The test setup used and measured behavior are described further together with the loading procedure. The anchorage reached the full capacity of the CFRP tendon and was seen to ensure a stable load of fracture. 相似文献
60.
Evaluation of assisting agents for electrodialytic removal of Cd,Pb, Zn,Cu and Cr from MSWI fly ash 总被引:7,自引:0,他引:7
Pedersen AJ 《Journal of hazardous materials》2002,95(1-2):185-198
Different assisting agents (0.25 M ammonium citrate/1.25% NH(3), 0.25 M Na-citrate, 2.5% NH(3), DI water) have been used for aiding the removal of heavy metals during electrodialytic treatment of municipal solid waste incineration (MSWI) fly ash. In this study, the effectiveness of the different agents was evaluated. The heavy metal speciation in solution was discussed and simulated at the different conditions using the geochemical equilibrium model Visual MINTEQ. The heavy metals examined were Cd, Pb, Zn, Cu and Cr.The 2.5% NH(3) solution was the best assisting agent for removal of Cd, probably due to formation of stable tetraammine complexes; whereas the best Pb removal was obtained with 0.25 M Na-citrate (Pb forms very stable chelates with citrate). The best compromise for removal of all five metals was obtained with the 0.25 M ammonium citrate/1.25% NH(3) solution. 相似文献