The recessive form of dystrophic epidermolysis bullosa (RDEB) is a crippling disease caused by impairments in the junctions of the dermis and the basement membrane of the epidermis. Using ectopic expression of hTERT/hTERT + BMI-1 in primary cells, we developed expansible cultures of RDEB fibroblasts and keratinocytes. We showed that they display the properties of their founders, including morphology, contraction ability and expression of the respective specific markers including reduced secretion of type VII collagen (C7). The immortalized keratinocytes retained normal stratification in 3D skin equivalents. The comparison of secreted protein patterns from immortalized RDEB and healthy keratinocytes revealed the differences in the contents of the extracellular matrix that were earlier observed specifically for RDEB. We demonstrated the possibility to reverse the genotype of immortalized cells to the state closer to the progenitors by the Cre-dependent hTERT switch off. Increased β-galactosidase activity and reduced proliferation of fibroblasts were shown after splitting out of transgenes. We anticipate our cell lines to be tractable models for studying RDEB from the level of single-cell changes to the evaluation of 3D skin equivalents. Our approach permits the creation of standardized and expandable models of RDEB that can be compared with the models based on primary cell cultures. 相似文献
Performance data are presented for methane oxidation on alumina-supported Pd, Pt, and Rh catalysts under both fuel-rich and fuel-lean conditions. Catalyst activity was measured in a micro-scale isothermal reactor at temperatures between 300 and 800 °C. Non-isothermal (near adiabatic) temperature and reaction data were obtained in a full-length (non-differential) sub-scale reactor operating at high pressure (0.9 MPa) and constant inlet temperature, simulating actual reactor operation in catalytic combustion applications.
Under fuel-lean conditions, Pd catalyst was the most active, although deactivation occurred above 650 °C, with reactivation upon cooling. Rh catalyst also deactivated above 750 °C, but did not reactivate. Pt catalyst was active above 600 °C. Fuel-lean reaction products were CO2 and H2O for all three catalysts.
The same catalysts tested under fuel-rich conditions demonstrated much higher activity. In addition, a ‘lightoff’ temperature was found (between 450 and 600 °C), where a stepwise increase in reaction rate was observed. Following ‘lightoff’ partial oxidation products (CO, H2) appeared in the mixture, and their concentration increased with increasing temperature. All three catalysts exhibited this behavior.
High-pressure (0.9 MPa) sub-scale reactor and combustor data are shown, demonstrating the benefits of fuel-rich operation over the catalyst for ultra-low emissions combustion. 相似文献
Understanding how the search space is explored for a given constraint problem – and how it changes for different models, solvers or search strategies – is crucial for efficient solving. Yet programmers often have to rely on the crude aggregate measures of the search that are provided by solvers, or on visualisation tools that can show the search tree, but do not offer sophisticated ways to navigate and analyse it, particularly for large trees. We present an architecture for profiling a constraint programming search that is based on a lightweight instrumentation of the solver. The architecture combines a visualisation of the search tree with various tools for convenient navigation and analysis of the search. These include identifying repeated subtrees, high-level abstraction and navigation of the tree, and the comparison of two search trees. The resulting system is akin to a traditional program profiler, which helps the user to focus on the parts of the execution where an improvement to their program would have the greatest effect. 相似文献
The chemical shift difference between signals of C() and C() of unsaturated ketones, , which we used before to measure acid strengths, has now been used to evaluate the hydrogen bond donor ability of solvents which are not acidic enough to hydronate the indicator. For such solvents there is no general correlation between H-bond donor ability and acid strength: hexa-fluoroisopropanol is a much weaker acid than acetic acid, but it is a stronger H-bond donor. The method can be applied to evaluate the H-bonding properties of solid surfaces, and it was thus found that silica gel has a much stronger H-bond donor ability than methanol or acetic acid. 相似文献
The measure of similarity between objects is a very useful tool in many areas of computer science, including information retrieval.
SimRank is a simple and intuitive measure of this kind, based on a graph-theoretic model. SimRank is typically computed iteratively,
in the spirit of PageRank. However, existing work on SimRank lacks accuracy estimation of iterative computation and has discouraging
time complexity. In this paper, we present a technique to estimate the accuracy of computing SimRank iteratively. This technique
provides a way to find out the number of iterations required to achieve a desired accuracy when computing SimRank. We also
present optimization techniques that improve the computational complexity of the iterative algorithm from O(n4) in the worst case to min(O(nl), O(n3/ log2n)), with n denoting the number of objects, and l denoting the number object-to-object relationships. We also introduce a threshold sieving heuristic and its accuracy estimation
that further improves the efficiency of the method. As a practical illustration of our techniques, we computed SimRank scores
on a subset of English Wikipedia corpus, consisting of the complete set of articles and category links. 相似文献
This paper proposes a technique for jointly quantizing continuous features and the posterior distributions of their class labels based on minimizing empirical information loss such that the quantizer index of a given feature vector approximates a sufficient statistic for its class label. Informally, the quantized representation retains as much information as possible for classifying the feature vector correctly. We derive an alternating minimization procedure for simultaneously learning codebooks in the euclidean feature space and in the simplex of posterior class distributions. The resulting quantizer can be used to encode unlabeled points outside the training set and to predict their posterior class distributions, and has an elegant interpretation in terms of lossless source coding. The proposed method is validated on synthetic and real data sets and is applied to two diverse problems: learning discriminative visual vocabularies for bag-of-features image classification and image segmentation. 相似文献
Let G=(VG,AG) be a digraph and let S⊔T be a bipartition of VG. A bibranching is a subset B⊆AG such that for each node s∈S there exists a directed s–T path in B and, vice versa, for each node t∈T there exists a directed S–t path in B. 相似文献
We review a number of formal verification techniques supported by STeP, the Stanford Temporal Prover, describing how the tool can be used to verify properties of several versions of the Bakery Mutual exclusion algorithm for mutual exclusion. We verify the classic two-process algorithm and simple variants, as well as an atomic parameterized version. The methods used include deductive verification rules, verification diagrams, automatic invariant generation, and finite-state model checking and abstraction. 相似文献
There has been increased interest on the impact of mobile devices such as PDAs and Tablet PCs in introducing new pedagogical
approaches and active learning experiences. We propose an intelligent system that efficiently addresses the inherent subjectivity
in student perception of note taking and information retrieval. We employ the idea of cross indexing the digital ink notes
with matching electronic documents in the repository. Latent Semantic Indexing is used to perform document and page level
indexing. Thus for each retrieved document, the user can go over to the relevant pages that match the query. Techniques to
handle problems such as polysemy (multiple meanings of a word) in large databases, document folding and no match for query
are discussed. We tested our system for its performance, usability and effectiveness in the learning process. The results
from the exploratory studies reveal that the proposed system provides a highly enhanced student learning experience, thereby
facilitating high test scores.
William I. GroskyEmail:
Akila Varadarajan
is a Senior Software Engineer at Motorola, IL with the Mobile devices division. Prior joining Motorola, she was a Software
development intern at Autodesk, MI and Graduate Research assistant at University of Michigan - Dearborn. She received her
MS in Computer Engineering from University of Michigan in 2006 and her BS in Computer Engineering from Madurai Kamaraj University,
India in 2003. She is interested in Mobile computing - specifically Human Factors of Mobile Computing, Information retrieval
and pattern recognition.
Nilesh Patel
is Assistant Professor in the department of Computer Science and Engineering at Oakland University, MI. He received his PhD
and MS in Computer Science from Wayne State University, MI in 1997 and 1993. He is interested in Multimedia Information Processing
- specifically audio and video indexing, retrieval and event detection, Pattern Recognition, Distributed Data Mining in a
heterogeneous environment, and Computer Vision with special interest in medical imaging. Dr. Patel has also served in the
automotive sector for several years and developed interest in Telematics and Mobile Computing.
Bruce Maxim
has worked as a software engineer for the past 31 years. He is a member of the Computer and Information Science faculty at
the University of Michigan-Dearborn since 1985. He serves as the computing laboratory supervisor and head of the undergraduate
programs in Computer Science, Software Engineering, and Information Systems. He has created more than 15 Computer and Information
Science courses dealing with software engineering, game design, artificial intelligence, user interface design, web engineering,
software quality, and computer programming. He has authored or co-authored four books on programming and software engineering.
He has most recently served on the pedagogy subcommittee for Software Engineering 2004 and contributed to the IDGA Game Curriculum
Framework 2008 guidelines.
William I. Grosky
is currently Professor and Chair of the Department of Computer and Information Science at University of Michigan - Dearborn,
Dearborn, Michigan. Prior to joining the University of Michigan in 2001, he was Professor and Chair of the Department of Computer
Science at Wayne State University, Detroit, Michigan. Before joining Wayne State University in 1976, he was an Assistant Professor
in the Department of Information and Computer Science at Georgia Tech, Atlanta, Georgia. He received his B.S. in Mathematics
from MIT in 1965, his M.S. in Applied Mathematics from Brown University in 1968, and his Ph.D. in Engineering and Applied
Science from Yale University in 1971.
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