Active vision-based localization for robots in a home-tour scenario

Self-Localization is a crucial task for mobile robots. It is not only a requirement for auto navigation but also provides contextual information to support human robot interaction (HRI). In this paper we present an active vision-based localization method for integration in a complex robot system to work in human interaction scenarios (e.g. home-tour) in a real world apartment. The holistic features used are robust to illumination and structural changes in the scene. The system uses only a single pan-tilt camera shared between different vision applications running in parallel to reduce the number of sensors. Additional information from other modalities (like laser scanners) can be used, profiting of an integration into an existing system. The camera view can be actively adapted and the evaluation showed that different rooms can be discerned

Machine learning of genomic profiles

Gegenstand dieser Arbeit ist das maschinelle Lernen und seine Anwendung auf genomische Profile. Maschinelles Lernen ist ein Teilbereich der Informatik, der sich mit der Analyse und dem Design von Algorithmen beschaftigt, die Regeln und Muster aus Datensätzen ableiten. Genomische Profile beschreiben Veränderungen der DNA, z.B. der Anzahl ihrer Kopien. Tumorerkrankungen werden oftmals von diesen genomischen Veränderungen hervorgerufen. Es werden verschiedene Verfahren des maschinellen Lernens auf ihre Anwendbarkeit in Bezug auf genomische Profile untersucht. Des Weiteren wird eine Verlustfunktion für Überlebenszeitdaten entworfen. Anschließend wird ein analytischer Bezugsrahmen entwickelt, um Aberrationsmuster zu finden, die mit einer speziellen Tumorerkrankung assoziiert sind. Der Bezugsrahmen umfaßt die Vorverarbeitung, Merkmalsselektion und Diskretisierung von genomischen Profilen sowie Strategien zum Umgang mit fehlenden Werten und eine mehrdimensionale Analyse. Abschließend folgen das Training und die Analyse des Klassifikators. In dieser Arbeit wird weiterhin eine Erklärungskomponente vorgestellt, die wichtige Merkmale für die Klassifikation eines Falles identifiziert und ein Maß für die Richtigkeit einer Klassifikation liefert. Solch eine Erklärungskomponente kann die Basis für die Integration eines Klassifikators , z.B. einer Support-Vektor-Maschine, in ein entscheidungsunterstützendes System sein. Die im Rahmen dieser Arbeit entwickelten Methoden wurden erfolgreich zur Beantwortung von biologischen Fragestellungen wie der frühen Metastasierung oder der Mikrometastasierung angewandt und führten zur Entdeckung bisher unbekannter Tumormarker. Zusammenfassend zeigen die Ergebnisse der vorliegenden Arbeit, dass Verfahren des maschinellen Lernens zum Erkenntnisgewinn in Bezug auf genomische Veränderungen beitragen und Möglichkeiten zu einer weiteren Verbesserung der Therapie für Tumorpatienten aufzeigen

CGH-Profiler: Data mining based on genomic aberration profiles

BACKGROUND: CGH-Profiler is a program that supports the analysis of genomic aberrations measured by Comparative Genomic Hybridisation (CGH). Comparative genomic hybridisation (CGH) is a well-established, molecular cytogenetic method that allows the detection of chromosomal imbalances in entire genomes. This technique is widely used in routine molecular diagnostics. Typically, chromosomal imbalances are described in a complex syntax based on the International Standard for Cytogenetic Nomenclature (ISCN). This semantic description of chromosomal imbalances hinders a large-scale statistical analysis across different experiments, e.g. for finding aberration patterns associated with a particular disease type or state. RESULTS: CGH-Profiler circumvents the semantic ISCN description by importing data from different CGH system vendors and by directly transferring the data into a table format that is readily accessible for subsequent statistical analysis. CGH-profiler comes with different consistency checks, calculates various statistics and automatically assigns a median copy number ratio to each chromosomal band. Import of CGH profiles from different CGH system vendors is already supported; its extension to other systems can be readily achieved through Perl scripts. CGH profiler can also be used to analyse comparative expressed sequence hybridisation (CESH) data. CESH reveals gene expression patterns according to chromosomal locations in a similar manner as CGH detects chromosomal imbalances. CONCLUSION: CGH-Profiler is a useful tool for processing of CGH and CESH data

GOPET: A tool for automated predictions of Gene Ontology terms

BACKGROUND: Vast progress in sequencing projects has called for annotation on a large scale. A Number of methods have been developed to address this challenging task. These methods, however, either apply to specific subsets, or their predictions are not formalised, or they do not provide precise confidence values for their predictions. DESCRIPTION: We recently established a learning system for automated annotation, trained with a broad variety of different organisms to predict the standardised annotation terms from Gene Ontology (GO). Now, this method has been made available to the public via our web-service GOPET (Gene Ontology term Prediction and Evaluation Tool). It supplies annotation for sequences of any organism. For each predicted term an appropriate confidence value is provided. The basic method had been developed for predicting molecular function GO-terms. It is now expanded to predict biological process terms. This web service is available via CONCLUSION: Our web service gives experimental researchers as well as the bioinformatics community a valuable sequence annotation device. Additionally, GOPET also provides less significant annotation data which may serve as an extended discovery platform for the user

Genomic analysis of single cytokeratin-positive cells from bone marrow reveals early mutational events in breast cancer

SummaryChromosomal instability in human breast cancer is known to take place before mammary neoplasias display morphological signs of invasion. We describe here the unexpected finding of a tumor cell population with normal karyotypes isolated from bone marrow of breast cancer patients. By analyzing the same single cells for chromosomal aberrations, subchromosomal allelic losses, and gene amplifications, we confirmed their malignant origin and delineated the sequence of genomic events during breast cancer progression. On this trajectory of genomic progression, we identified a subpopulation of patients with very early HER2 amplification. Because early changes have the highest probability of being shared by genetically unstable tumor cells, the genetic characterization of disseminated tumor cells provides a novel rationale for selecting patients for targeted therapies

Wearable devices can predict the outcome of standardized 6-minute walk tests in heart disease

Wrist-worn devices with heart rate monitoring have become increasingly popular. Although current guidelines advise to consider clinical symptoms and exercise tolerance during decision-making in heart disease, it remains unknown to which extent wearables can help to determine such functional capacity measures. In clinical settings, the 6-minute walk test has become a standardized diagnostic and prognostic marker. We aimed to explore, whether 6-minute walk distances can be predicted by wrist-worn devices in patients with different stages of mitral and aortic valve disease. A total of n = 107 sensor datasets with 1,019,748 min of recordings were analysed. Based on heart rate recordings and literature information, activity levels were determined and compared to results from a 6-minute walk test. The percentage of time spent in moderate activity was a predictor for the achievement of gender, age and body mass index-specific 6-minute walk distances (p < 0.001; R2 = 0.48). The uncertainty of these predictions is demonstrated

Targeted delivery of a phosphoinositide 3-kinase γ inhibitor to restore organ function in sepsis

Jaundice, the clinical hallmark of infection-associated liver dysfunction, reflects altered membrane organization of the canalicular pole of hepatocytes and portends poor outcomes. Mice lacking phosphoinositide 3-kinase-γ (PI3Kγ) are protected against membrane disintegration and hepatic excretory dysfunction. However, they exhibit a severe immune defect that hinders neutrophil recruitment to sites of infection. To exploit the therapeutic potential of PI3Kγ inhibition in sepsis, a targeted approach to deliver drugs to hepatic parenchymal cells without compromising other cells, in particular immune cells, seems warranted. Here, we demonstrate that nanocarriers functionalized through DY-635, a fluorescent polymethine dye, and a ligand of organic anion transporters can selectively deliver therapeutics to hepatic parenchymal cells. Applying this strategy to a murine model of sepsis, we observed the PI3Kγ-dependent restoration of biliary canalicular architecture, maintained excretory liver function, and improved survival without impairing host defense mechanisms. This strategy carries the potential to expand targeted nanomedicines to disease entities with systemic inflammation and concomitantly impaired barrier functionality

The calibration system for the photomultiplier array of the SNO+ experiment

A light injection system using LEDs and optical fibres was designed for the calibration and monitoring of the photomultiplier array of the SNO+ experiment at SNOLAB. Large volume, non-segmented, low-background detectors for rare event physics, such as the multi-purpose SNO+ experiment, need a calibration system that allow an accurate and regular measurement of the performance parameters of their photomultiplier arrays, while minimising the risk of radioactivity ingress. The design implemented for SNO+ uses a set of optical fibres to inject light pulses from external LEDs into the detector. The design, fabrication and installation of this light injection system, as well as the first commissioning tests, are described in this paper. Monte Carlo simulations were compared with the commissioning test results, confirming that the system meets the performance requirements