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121.
The influence of an addition of either sand and/or spring-bloom algae on the efflux of nutrients from intact sediment cores from the Baltic Sea was studied in a flow-through experiment. The addition of sand significantly increased the efflux of silicon (Si) from sediment, but the algal addition did not. The effects on phosphorus (P) were not as clear, and fluxes of nitrogen (NH4 and NO2?+?3) remained relatively unaffected by the additions. The small effect of the algal addition was caused by the short time-period covered by the experiment and possibly by adsorption of released Si by the sediment. A follow-up bottle experiment showed that despite the apparently lower content of easily available Si and biogenic silica, BSi, in the sand, the sand-induced Si efflux was caused by release of Si from the sand itself, rather than by indirectly increasing the dissolution of BSi present in the sediment. 相似文献
122.
123.
Scialfa Charles T.; Hamaluk Eleanor; Skaloud Petra; Pratt Jay 《Canadian Metallurgical Quarterly》1999,14(4):695
Younger and older adults were asked to saccade to an orientation-defined target that was presented alone, with a more central distractor, or with a more peripheral distractor. Both age groups exhibited saccadic averaging that was more pronounced in the central distractor condition, wherein older adults had the larger effect. These results are relevant to questions of oculomotor control and also have implications for the study of age differences in other visually guided behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
124.
Zusammenfassung Das Zeichnen von Graphen ist ein junges aufblühendes Gebiet der Informatik. Es befa?t sich mit Entwurf, Analyse, Implementierung
und Evaluierung von neuen Algorithmen für ?sthetisch sch?ne Zeichnungen von Graphen. Anhand von selektierten Anwendungsbeispielen,
Problemstellungen und L?sungsans?tzen wollen wir in dieses noch relativ unbekannte Gebiet einführen und gleichzeitig einen
überblick über die Aktivit?ten und Ziele einer von der DFG im Rahmen des Schwerpunktprogramms „Effiziente Algorithmen für
Diskrete Probleme und ihre Anwendungen“ gef?rderten Arbeitsgruppe aus Mitgliedern der Universit?ten Halle, K?ln und Passau
und des Max-Planck-Instituts für Informatik in Saarbrücken geben.
Eingegangen am 22.05.1996, in überarbeiteter Form am 19.02.1997 相似文献
125.
多年来我一直关注和期待着厂商宣布磁盘存储退出。最近,这件事终于发生了。做出这一个大胆声明的厂商是Sun公司,具体讲是Sun公司的CEO和总裁Jonathan Schwartz。 相似文献
126.
In order to increase the wear resistance of metal forming tools, four different cold and hot working steels were laser-beam surface melted and alloyed with titanium carbide and vanadium carbide. The layers were investigated concerning chemical composition, microstructure, hardness profiles, wear behaviour measured by pin-on-disk-tests with different counterbodies and plastic behaviour of the surface by a new developed repeated impact testing machine. It turned out to be more useful to take a substrate which is already quenched and tempered prior to the laser-beam surface treatment than to carry out the tool hardening heat treatment afterwards. A tempering step after the laser-beam alloying offers the advantage of carbide precipitates in the layer connected with an increase in the hardness and a reduction of residual stresses. By means of laser-beam surface alloying the wear protection of the layer can be increased while the alloying content of the substrate is reduced with respect to the core fracture toughness. The optimal alloying addition depends on the demands of the envisaged application. 相似文献
127.
Petra Dassen-Housen 《AI & Society》2002,16(3):188-209
In this paper, some fundamental aspects of societal change processes are described, leading to proposals of how to cope with
such changes through continuous learning within society. This change society is presently emerging worldwide. It is very much
shaped by advanced networked information and communication technology. Correspondingly, certain trends are identified in this
paper which indicate the change processes towards this new emerging society. Subsequently, different personal skills are described
which are required for all members of society to cope with these trends. The paper finishes with a case study which deals
with regional development through open networked business processes. The aim of the project described was to develop a joint
family vacation concept in the former socialist East German state of Saxonia. Thus, it illustrates the change and learning
processes across society which have taken place in many countries after the socialist era. 相似文献
128.
Mahdi Bagherpoor Helabad Natalia Kanaan Petra Imhof 《International journal of molecular sciences》2014,15(7):11799-11816
Distortions in the DNA sequence, such as damage or mispairs, are specifically recognized and processed by DNA repair enzymes. Many repair proteins and, in particular, glycosylases flip the target base out of the DNA helix into the enzyme’s active site. Our molecular dynamics simulations of DNA with intact and damaged (oxidized) methyl-cytosine show that the probability of being flipped is similar for damaged and intact methyl-cytosine. However, the accessibility of the different 5-methyl groups allows direct discrimination of the oxidized forms. Hydrogen-bonded patterns that vary between methyl-cytosine forms carrying a carbonyl oxygen atom are likely to be detected by the repair enzymes and may thus help target site recognition. 相似文献
129.
130.
Derivatization of Antibody Fab Fragments: A Designer Enzyme for Native Protein Modification
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Dr. Sandra Liebscher Dr. Petra Kornberger Gerhard Fink Dr. Eva‐Maria Trost‐Gross Dr. Eva Höss Prof. Dr. Arne Skerra Prof. Dr. Frank Bordusa 《Chembiochem : a European journal of chemical biology》2014,15(8):1096-1100
Bioconjugates, such as antibody–drug conjugates, have gained recent attention because of their increasing use in therapeutic and diagnostic applications. Commonly used conjugation reactions based upon chemoselective reagents exhibit a number of drawbacks: most of these reactions lack regio‐ and stereospecificity, thus resulting in loss of protein functionality due to random modifications. Enzymes provide an obvious solution to this problem, but the intrinsic (natural) substrate specificities of existing enzymes pose severe limitations to the kind of modifications that can be introduced. Here we describe the application of the novel trypsin variant trypsiligase for site‐specific modification of the C terminus of a Fab antibody fragment via a stable peptide bond. The suitability of this designed biocatalyst was demonstrated by coupling the Her2‐specific Fab to artificial functionalities of either therapeutic (PEG) or diagnostic (fluorescein) relevance. In both cases we obtained homogeneously modified Fab products bearing the artificial functionality exclusively at the desired position. 相似文献