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41.
42.
Pick-and-place nanomanipulation using microfabricated grippers   总被引:1,自引:0,他引:1  
Microfabricated grippers could be useful for the manipulation of nanoscopic and microscopic samples. A survey is presented of the force requirements for a microgripper to complete pick-and-place nanomanipulation tasks. We then demonstrate in?situ pick-and-place operations of nanowires inside a scanning electron microscope using microfabricated electrostatically actuated grippers, and compare the theoretically estimated force requirements with the results of experimental tests of picking up nanowires to evaluate how grippers and strategies for nanomanipulation can be optimized.  相似文献   
43.
In this study a chromatographic approach for fluorescence reduction in liquid Raman analysis has been evaluated. The idea behind the approach is to apply a chromatographic separation step prior to Raman analysis in order to separate fluorescing compounds from other components of interest, thus facilitating better quantitative and qualitative analysis of the latter components. A real-time liquid-core Raman waveguide detector designed for chromatographic applications was used in the study, thus providing real-time chemical pretreatment of liquid samples for Raman analysis. Twenty aqueous mixtures of additives frequently found in beverages were analyzed, and for comparative purposes the mixtures were also analyzed in the Raman waveguide detector without chromatographic separation and with a conventional immersion probe. Both qualitatively and quantitatively satisfying results were obtained using the chromatographic Raman approach, and the technique provided possibilities for quantitative and qualitative assessments superior to the two other instrumental setups. The technique may provide additional benefits through sensitivity enhancements, and the approach is simple, inexpensive, and easy to implement in the average applied Raman laboratory. The analysis of various chemical systems and factors such as system stability over time need further evaluation in order to confirm the general applicability of the approach.  相似文献   
44.
Chronic otitis media is a common disease often accompanied by recurrent bacterial infections. These may lead to the destruction of the middle ear bones such that prostheses have to be implanted to restore sound transmission. Surface coatings with layered double hydroxides (LDHs) are evaluated here as a possibility for drug delivery systems with convenient advantages such as low cytotoxicity and easy synthesis. Male New Zealand White rabbits were implanted with Bioverit® II middle ear prostheses coated with the LDH Mg4Al2(OH)12(SO4)2·6H2O impregnated with ciprofloxacin. 12 (group 1) were directly infected with Pseudomonas aeruginosa and another 12 (group 2) 1 week after the implantation. Clinical outcome, blood counts, histological analyses and microbiological examination showed an excellent antimicrobial activity for group 1, whereas this effect was attenuated in animals where infection was performed 1 week after implantation. This is the first study to demonstrate an efficient drug delivery system with an LDH coating on prostheses in the middle ear.  相似文献   
45.
We have performed an extended replication of the Porter-Votta-Basili experiment comparing the Scenario method and the Checklist method for inspecting requirements specifications using identical instruments. The experiment has been conducted in our educational context represented by a more general definition of a defect compared to the original defect list. Our study involving 24 undergraduate students manipulated three independent variables: detection method, requirements specification, and the order of the inspections. The dependent variable measured is the defect detection rate. We found the requirements specification inspected and not the detection method to be the most probable explanation for the variance in defect detection rate. This suggests that it is important to gather knowledge of how a requirements specification can convey an understandable view of the product and to adapt inspection methods accordingly. Contrary to the original experiment, we can not significantly support the superiority of the Scenario method. This is in accordance with a replication conducted by Fusaro, Lanubile and Visaggio, and might be explained by the lack of individual defect detection skill of our less experienced subjects.  相似文献   
46.
Many tasks in AI require representation and manipulation of complex functions. First-Order Decision Diagrams (FODD) are a compact knowledge representation expressing functions over relational structures. They represent numerical functions that, when constrained to the Boolean range, use only existential quantification. Previous work has developed a set of operations for composition and for removing redundancies in FODDs, thus keeping them compact, and showed how to successfully employ FODDs for solving large-scale stochastic planning problems through the formalism of relational Markov decision processes (RMDP). In this paper, we introduce several new ideas enhancing the applicability of FODDs. More specifically, we first introduce Generalized FODDs (GFODD) and composition operations for them, generalizing FODDs to arbitrary quantification. Second, we develop a novel approach for reducing (G)FODDs using model checking. This yields – for the first time – a reduction that maximally reduces the diagram for the FODD case and provides a sound reduction procedure for GFODDs. Finally we show how GFODDs can be used in principle to solve RMDPs with arbitrary quantification, and develop a complete solution for the case where the reward function is specified using an arbitrary number of existential quantifiers followed by an arbitrary number of universal quantifiers.  相似文献   
47.
Interest in psychological experimentation from the Artificial Intelligence community often takes the form of rigorous post-hoc evaluation of completed computer models. Through an example of our own collaborative research, we advocate a different view of how psychology and AI may be mutually relevant, and propose an integrated approach to the study of learning in humans and machines. We begin with the problem of learning appropriate indices for storing and retrieving information from memory. From a planning task perspective, the most useful indices may be those that predict potential problems and access relevant plans in memory, improving the planner's ability to predict and avoid planning failures. This predictive features hypothesis is then supported as a psychological claim, with results showing that such features offer an advantage in terms of the selectivity of reminding because they more distinctively characterize planning situations where differing plans are appropriate.We present a specific case-based model of plan execution, RUNNER, along with its indices for recognizing when to select particular plans—appropriateness conditions—and how these predictive indices serve to enhance learning. We then discuss how this predictive features claim as implemented in the RUNNER model is then tested in a second set of psychological studies. The results show that learning appropriateness conditions results in greater success in recognizing when a past plan is in fact relevant in current processing, and produces more reliable recall of the related information. This form of collaboration has resulted in a unique integration of computational and empirical efforts to create a model of case-based learning.  相似文献   
48.
The direct observation of cells over time using time-lapse microscopy can provide deep insights into many important biological processes. Reliable analyses of motility, proliferation, invasive potential or mortality of cells are essential to many studies involving live cell imaging and can aid in biomarker discovery and diagnostic decisions. Given the vast amount of image- and time-series data produced by modern microscopes, automated analysis is a key feature to capitalize the potential of time-lapse imaging devices. To provide fast and reproducible analyses of multiple aspects of cell behaviour, we developed TimeLapseAnalyzer. Apart from general purpose image enhancements and segmentation procedures, this extensible, self-contained, modular cross-platform package provides dedicated modalities for fast and reliable analysis of multi-target cell tracking, scratch wound healing analysis, cell counting and tube formation analysis in high throughput screening of live-cell experiments. TimeLapseAnalyzer is freely available (MATLAB, Open Source) at http://www.informatik.uni-ulm.de/ni/mitarbeiter/HKestler/tla.  相似文献   
49.
Following calls to advance the integration of risk and business process modeling paradigms, this paper formalizes the process of incorporating risk into business process models through the principles of Value-Focused Process Engineering (VFPE). In doing so, the paper aims to extend the existing VFPE modeling notation to reflect a set of necessary constructs required to adequately represent risk in goal-oriented business-process models. The extended set of constructs is proposed to support a formal systems view of process-based risk. Process-based risk is formalized on the one hand, as a product of complex interactions between activity-based elements, and on the other hand, as a natural component of the value creation mechanism of an elementary function or a complex process. The proposed risk-aware VFPE formalism also formulates rules for decomposing risk in process models according to the organizational values, thereby enabling better risk visibility, reducing process complexity, and ensuring continuity of business processes.  相似文献   
50.
    
Nanowires are commonly used as tools for interfacing living cells, acting as biomolecule‐delivery vectors or electrodes. It is generally assumed that the small size of the nanowires ensures a minimal cellular perturbation, yet the effects of nanowires on cell migration and proliferation remain largely unknown. Fibroblast behaviour on vertical nanowire arrays is investigated, and it is shown that cell motility and proliferation rate are reduced on nanowires. Fibroblasts cultured on long nanowires exhibit failed cell division, DNA damage, increased ROS content and respiration. Using focused ion beam milling and scanning electron microscopy, highly curved but intact nuclear membranes are observed, showing no direct contact between the nanowires and the DNA. The nanowires possibly induce cellular stress and high respiration rates, which trigger the formation of ROS, which in turn results in DNA damage. These results are important guidelines to the design and interpretation of experiments involving nanowire‐based transfection and electrical characterization of living cells.  相似文献   
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