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排序方式: 共有350条查询结果,搜索用时 31 毫秒
91.
Pederin, a hemolymph toxin found in the rove beetle genusPaederus, is quantified in individual specimens ofP. fuscipes andP. riparius. Whereas males always contain only small quantities of the toxin (0.1–1.5 µg), females are not so restricted (0.2–20.5 µg) and in most cases possess roughly 10-fold that in males. There are, however, females containing as little pederin as the males, and so two clearly separate groups of females can be discerned. These two groups hint at two types of females defined by the eggs they lay. About 85% of the females, i.e., those containing much of the substance, transfer pederin into every egg and thus are denoted (+)-females. The remaining 15%, the (–)-females, contain at best small amounts of the toxin, which is transferred in minute quantities into the first eggs while the subsequent ones lack pederin. With respect to the pederin content of their eggs, there is no overlap between these two types of females. If fed with pederin, (–)-females can transfer it into the eggs like (+)-females. After hatching the larvae store pederin when present. Larvae are not able to biosynthesize the toxin on their own, but storage of that received in the egg is very efficient, and the difference between larvae with and without pederin is preserved until imaginal eclosion. In (+)-females, pederin increases, probably reflecting a biosynthetic capacity, but in males and presumptive (–)-females the amount of pederin never exceeds the quantity transferred by parental (+)-females. Consequently, males and (–)-females probably are unable to biosynthesize pederin. This polymorphism of females may have a genetic basis. Individuals of all stages nevertheless sequester pederin if it is supplied with the diet. 相似文献
92.
Theodor J. Stewart Ron Janssen 《International Transactions in Operational Research》2013,20(4):559-578
In this article, an integrated structure is provided for processing various forms of imprecise preference information in the context of multicriteria impact assessments. Linear programing formulations generate best‐fit value function models and associated ranking of alternatives, both when preferences are overdetermined (leading to potential inconsistencies) or when preference information is incomplete. In the latter context, the algorithm identifies a range of possible rank orders for the decision alternatives under consideration, consistent with the information provided. The approach is primarily aimed at structuring opinions of experts concerning the desirability of different actions in terms of technical aspects, intended as input into the final political decision‐making process. It is demonstrated that the approach described here can be implemented with modest levels of effort by the experts. Experience is reported with the approach in the context of soil sanitation problem in the Netherlands, in which experts expressed satisfaction with the resulting rank ordering of alternatives. 相似文献
93.
This paper provides background on requirements, capabilities and research recommendations for protecting critical infrastructure
systems. These activities are needed to develop much more effective solutions to problems that can be currently addressed
primarily with conservative, and/or empirical approaches. The expected contributions will have a profound effect on national
and international defense and security. Although essential work must be conducted in several important areas, this paper is
primarily focused on scientific and technical issues. 相似文献
94.
An Intelligent Evacuation,Rescue and Recovery Concept 总被引:1,自引:0,他引:1
Recent terrorist incidents have demonstrated that personnel responsible for decision-making in post-attack and structural
fire evacuation, rescue and recovery (ERR) activities can significantly benefit from an expert decision support system. In
this paper, a concept is proposed for such an expert system that, through the use of sensor technology, can permit real-time
assessment of the extent of blast and fire damage to a building, can recommend immediate actions that can be taken to mitigate
the situation and prevent further deterioration, can monitor the growth and spread of fire and smoke, and can be used to aid
the rescue workers and evacuees in rescue efforts and safe egress. This comprehensive system, once fully operational, can
be used for training, blast damage assessment (BDA), target vulnerability assessment (TVA), pre-event emergency preparedness
planning, and post-attack ERR operations. The key capabilities of this system stem from the electronic integration of two
critical components: a near real-time intelligent BDA/TVA tool and on-line ERR-related optimization techniques. The implementation
of this concept will support faster and more efficient evacuation of a building, ship, or other large structure in the event
of military attack, fire, natural disaster, chemical attack, discovery of hazardous materials or biological agents, or other
circumstances warranting quick escape. 相似文献
95.
96.
Fully Automated Production and Characterization of 64Cu and Proof‐of‐Principle Small‐Animal PET Imaging Using 64Cu‐Labelled CA XII Targeting 6A10 Fab
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Luise Fiedler Dr. Markus Kellner Rosel Oos PD Dr. Guido Böning Prof. Sibylle Ziegler Prof. Peter Bartenstein Prof. Reinhard Zeidler Dr. Franz Josef Gildehaus Dr. Simon Lindner 《ChemMedChem》2018,13(12):1230-1237
64Cu is a cyclotron‐produced radionuclide which offers, thanks to its characteristic decay scheme, the possibility of combining positron emission tomography (PET) investigations with radiotherapy. We evaluated the Alceo system from Comecer SpA to automatically produce 64Cu for radiolabelling purposes. We established a 64Cu production routine with high yields and radionuclide purity in combination with excellent operator radiation protection. The carbonic anhydrase XII targeting 6A10 antibody Fab fragment was successfully radiolabelled with the produced 64Cu, and proof‐of‐principle small‐animal PET experiments on mice bearing glioma xenografts were performed. We obtained a high tumor‐to‐contralateral muscle ratio, which encourages further in vivo investigations of the radioconjugate regarding a possible application in diagnostic tumor imaging. 相似文献
97.
Jan Rudolph Naceur Gaaloul Yeshpal Singh Holger Ahlers Waldemar Herr Torben A. Schulze Stephan Tobias Seidel Christina Rode Vladimir Schkolnik Wolfgang Ertmer Ernst Maria Rasel Hauke Müntinga Thorben Könemann Andreas Resch Sven Herrmann Claus Lämmerzahl Tim van Zoest Hansjörg Dittus Anika Vogel André Wenzlawski Klaus Sengstock Nadine Meyer Kai Bongs Markus Krutzik Wojciech Lewoczko-Adamczyk Max Schiemangk Achim Peters Michael Eckart Endre Kajari Stefan Arnold Gerrit Nandi Wolfgang P. Schleich Reinhold Walser Tilo Steinmetz Theodor W. Hänsch Jakob Reichel 《Microgravity science and technology》2011,23(3):287-292
Clouds of ultra-cold atoms and especially Bose–Einstein condensates (BEC) provide a source for coherent matter-waves in numerous earth bound experiments. Analogous to optical interferometry, matter-wave interferometers can be used for precision measurements allowing for a sensitivity orders of magnitude above their optical counterparts. However, in some respects the presence of gravitational forces in the lab limits experimental possibilities. In this article, we report about a compact and robust experiment generating Bose–Einstein condensates in the drop tower facility in Bremen, Germany. We also present the progress of building the succeeding experiment in which a two species atom interferometer will be implemented to test the weak equivalence principle with quantum matter. 相似文献
98.
Alexandru Dumitrache Theodor Borangiu 《Engineering Applications of Artificial Intelligence》2012,25(6):1161-1172
This paper presents a NC toolpath generation strategy with tool engagement control for arbitrarily complex discrete part geometry, which reduces machining time and tool wear and can be used in high speed machining. The toolpath computation is based on image models for design part, raw stock and cutting tool, and involves pixel-based simulation of the milling process. Simulation results and comparison with existing methods are presented. 相似文献
99.
Iñigo Bretos Theodor Schneller Rainer Waser Detlev F. Hennings Daesung Park Thomas Weirich 《Journal of the American Ceramic Society》2013,96(4):1228-1233
The substitution in (Ba0.70Sr0.30)TiO3 thin films by the rare‐earth element dysprosium prepared at 1000°C by chemical solution deposition on nickel foils was investigated. The relatively large thermal budget applied (via annealing temperature) is shown to enhance the solubility of the Dy3+doping ion into the crystal lattice of the perovskite films. Preference for B‐site occupancy of this amphoteric cation was further promoted by the addition of BaO excess (1 mol%), which results in slightly larger grains in the films as observed by scanning electron microscopy. Despite this Ba‐rich composition, the presence of secondary phases in the thin films was not detected by X‐ray diffraction. Transmission electron microscopy revealed no evidence for local segregation of Dy at grain boundaries, neither the formation of NiO at the interface between the film and the metal foil was observed. The substitution of Ti4+ by Dy3+ leads to the formation of strong electron acceptors in the system, which balance the number of ionized oxygen vacancies arisen from the reductive crystallization atmosphere used during processing. As a consequence, the dielectric loss (tan σ) and leakage conduction measured in the resulting thin‐film capacitors were significantly reduced with respect to nominally undoped samples. The improvement of this capacitor feature, combined with the relatively high permittivities obtained in the films (490–530), shows the effectiveness of dysprosium doping within a thin‐film fabrication method for potential application into the multilayer ceramic capacitor technology. 相似文献
100.
Marco Aurélio dos Santos Bernardes Theodor W. Von Backström Detlev G. Kröger 《Solar Energy》2009,83(2):264-275
A solar chimney power plant consists of a translucent collector which heats the air near the ground and guides it into the base of a chimney at its centre. The buoyant air rises in the chimney and electricity is generated through one or more turbines in or near the base of the chimney. Various studies about solar chimney power plant performance have been published. Different calculation approaches with a variety of considerations have been applied to calculate chimney power plant performance. In particular, two comprehensive studies are relevant, namely those of (Bernardes, M.A.d. S., Voß, A., Weinrebe, G., 2003. Thermal and technical analyses of solar chimneys. Solar Energy 75, 511-524; Pretorius, J.P., Kröger, D.G., 2006b. Solar chimney power plant performance. Transactions of the ASME 128, 302-311). The paper compares the methods used to calculate the heat fluxes in the collector, and their effects on solar chimney performance. Reasons for the discrepancies between the predictions of the two models are given. In general the Pretorius model produces higher heat transfer coefficients and higher heat rate fluxes for both the roof and for the ground surfaces. The two approaches lead to very similar air temperature rises in the collector and thus, similar produced power. 相似文献