75 research outputs found
Clinical study to assess influence of immediate provisionalization and various implant morphologies on implant stability: A prospective clinical study
IntroductionThe aim of this study was to evaluate the influence of different implant morphologies and immediate provisionalization options on the change of implant stability.Methods94 Patients were randomized to receive implants from Straumann® BL/Straumann® BLT/Astra OsseoSpeed® TX, meanwhile having the same opportunity to receive healing abutment or immediate provisionalization. Implant stability quotient (ISQ) and marginal bone loss (MBL) were recorded at following timepoints. Parametric statistic was used for data analysis.ResultsData showed that ISQ and MBL values of conical/straight/straight with micro-thread neck implants had no significant difference.DiscussionImmediate provisionalization options could move the dip point of ISQ values ahead or delayed around one week, which were also relevant to implant systems. MBL values were proved to be unaffected by both two factors mentioned above
ImageSpace: An Environment for Image Ontology Management
More and more researchers have realized that ontologies will play a critical role in the development of
the Semantic Web, the next generation Web in which content is not only consumable by humans, but also by
software agents. The development of tools to support ontology management including creation, visualization,
annotation, database storage, and retrieval is thus extremely important. We have developed ImageSpace, an
image ontology creation and annotation tool that features (1) full support for the standard web ontology language
DAML+OIL; (2) image ontology creation, visualization, image annotation and display in one integrated framework;
(3) ontology consistency assurance; and (4) storing ontologies and annotations in relational databases. It is
expected that the availability of such a tool will greatly facilitate the creation of image repositories as islands of the
Semantic Web
Incremental Genetic K-means Algorithm and its Application in Gene Expression Data Analysis
Background
In recent years, clustering algorithms have been effectively applied in molecular biology for gene expression data analysis. With the help of clustering algorithms such as K-means, hierarchical clustering, SOM, etc, genes are partitioned into groups based on the similarity between their expression profiles. In this way, functionally related genes are identified. As the amount of laboratory data in molecular biology grows exponentially each year due to advanced technologies such as Microarray, new efficient and effective methods for clustering must be developed to process this growing amount of biological data. Results
In this paper, we propose a new clustering algorithm, Incremental Genetic K-means Algorithm (IGKA). IGKA is an extension to our previously proposed clustering algorithm, the Fast Genetic K-means Algorithm (FGKA). IGKA outperforms FGKA when the mutation probability is small. The main idea of IGKA is to calculate the objective value Total Within-Cluster Variation (TWCV) and to cluster centroids incrementally whenever the mutation probability is small. IGKA inherits the salient feature of FGKA of always converging to the global optimum. C program is freely available at http://database.cs.wayne.edu/proj/FGKA/index.htm. Conclusions
Our experiments indicate that, while the IGKA algorithm has a convergence pattern similar to FGKA, it has a better time performance when the mutation probability decreases to some point. Finally, we used IGKA to cluster a yeast dataset and found that it increased the enrichment of genes of similar function within the cluster
Quantum phase transition in magnetic nanographenes on a lead superconductor
Quantum spins, referred to the spin operator preserved by full SU(2) symmetry
in the absence of the magnetic anistropy, have been proposed to host exotic
interactions with superconductivity4. However, spin orbit coupling and crystal
field splitting normally cause a significant magnetic anisotropy for d/f-shell
spins on surfaces6,9, breaking SU(2) symmetry and fabricating the spins with
Ising properties10. Recently, magnetic nanographenes have been proven to host
intrinsic quantum magnetism due to their negligible spin orbital coupling and
crystal field splitting. Here, we fabricate three atomically precise
nanographenes with the same magnetic ground state of spin S=1/2 on Pb(111)
through engineering sublattice imbalance in graphene honeycomb lattice.
Scanning tunneling spectroscopy reveals the coexistence of magnetic bound
states and Kondo screening in such hybridized system. Through engineering the
magnetic exchange strength between the unpaired spin in nanographenes and
cooper pairs, quantum phase transition from the singlet to the doublet state
has been observed, in consistent with quantum models of spins on
superconductors. Our work demonstrates delocalized graphene magnetism host
highly tunable magnetic bound states with cooper pairs, which can be further
developed to study the Majorana bound states and other rich quantum physics of
low-dimensional quantum spins on superconductors.Comment: 13 pages, 4figure
Determination of the transport lifetime limiting scattering rate in InSb/Al<inf>x</inf>In<inf>1−x</inf> Sb quantum wells using optical surface microscopy
We report magnetotransport measurements of InSb/Al1−xInxSb quantum well structures at low temperature (3 K), with evidence for 3 characteristic regimes of electron carrier density and mobility. We observe characteristic surface structure using differential interference contrast DIC (Nomarski) optical imaging, and through use of image analysis techniques, we are able to extract a representative average grain feature size for this surface structure. From this we deduce a limiting low temperature scattering mechanism not previously incorporated in transport lifetime modelling of this system, with this improved model giving strong agreement with standard low temperature Hall measurements. We have demonstrated that the mobility in such a material is critically limited by quality from the buffer layer growth, as opposed to fundamental material scattering mechanisms. This suggests that the material has immense potential for mobility improvement over that reported to date
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