254 research outputs found
Novel Biomarkers for Heart Disease
No full textCardiac biomarkers such as troponins and natiuretic peptides have made a great impact on clinical decision making as well as improving our understanding of molecular mechanisms of different disease conditions. However, the biomarkers that are currently in use do not reflect all the multiple disease pathways that are involved in a broad spectrum of cardiac disease conditions ranging from acute coronary syndrome, to heart failure (and heart failure with preserved ejection fraction, HFpEF), to pulmonary hypertension or arrhythmias. In this Special Issue, we will provide an overview of the current developments in the field of biomarker research, beginning with research on molecular pathways and cellular communication (e.g., microRNA) up to the clinical use of biomarkers
Novel Biomarkers for Heart Disease
No full textCardiac biomarkers such as troponins and natiuretic peptides have made a great impact on clinical decision making as well as improving our understanding of molecular mechanisms of different disease conditions. However, the biomarkers that are currently in use do not reflect all the multiple disease pathways that are involved in a broad spectrum of cardiac disease conditions ranging from acute coronary syndrome, to heart failure (and heart failure with preserved ejection fraction, HFpEF), to pulmonary hypertension or arrhythmias. In this Special Issue, we will provide an overview of the current developments in the field of biomarker research, beginning with research on molecular pathways and cellular communication (e.g., microRNA) up to the clinical use of biomarkers
Gesture Recognition by Computer Vision: An Integral Approach
No full textThe fundamental objective of this Ph.D. thesis is to gain more insight into what is involved in the practical application of a computer vision system, when the conditions of use cannot be controlled completely. The basic assumption is that research on isolated aspects of computer vision often leads to `too' general solutions. That these solutions lack the robustness and accuracy, which could only be achieved by an integral approach of a specific application. Furthermore, an integral approach, and actually trying out a computer vision system in practice, can lead to new insights that can determine the direction of future research in computer vision. The application for the research in this thesis is automatic sign recognition for feedback in active learning with an electronic learning environment for sign language. The goal of this learning environment is to enlarge the vocabulary of deaf and hard of hearing children, between the age of 3 and 5, in order to facilitate in decreasing a delay in language development. The research has been focussed on a number of aspects that were assumed to have the most influence on the robustness of sign recognition. These were: tracking of movements, the extraction of relevant structure information from an image, skin color detection, including the third dimension of hand locations, dealing with variations of time as well as shape of a sign and reducing the required effort to teach the system to recognize a new sign. `Particle filtering' is a popular method to track hand movement. However, tests with the CONDENSATION algorithm show contradictions in dealing with different situations. When the motion is unpredictable (as is the case with tracking of human hands) a particle filter has difficulty to keep track of the object. It turns out that, under different conditions, different strategies are required to deal with this in the best possible way. Isophote properties can be used as local abstractions of an image. One advantage of isophote properties is that they are independent of image contrast. In experiments with face detection using isophote properties, the results are superior to using pixels, gradients, or the popular Haar features. Because face detection requires significant computational cost, and the methods involved are less suitable for detection of hands, it is appealing to detect these body parts on the basis of their color alone. Unfortunately, color behaves less predictable in practical situations, than can be described by a single light-reflection model. Deviations from physical models for reflection are caused by properties and settings of the camera that is used, but also by the combination of different light sources and reflections. By combining these uncertainties in a more general model, robustness can be obtained in unknown circumstances. Unfortunately, this generalization comes at the price of accuracy in more friendly conditions. To combine robustness with accuracy, we have proposed an adaptive chromatic model, which can use a small set of measurements to model variation of the color of a face, using a bi-modal piecewise linear model in the red/green/blue space. Sign language takes place in a three-dimensional space, while images only allow measurements in two dimensions. Therefore, we have used stereometry to convert the measured hand locations in the images from two cameras into three-dimensional positions of the hands in space. The experiments show that this richer information does indeed lead to an improvement in sign recognition. Alternatively, the perspective of a single wide-angle camera at a short distance turned out to achieve a comparable improvement. However, the disadvantage of the latter solution is a decreased robustness, because perspective depends highly on the location of a person relative to the camera. Using dynamic recognition methods, like ``Hidden Markov Models'' (HMM) or Statistical ``Dynamic Time Warping'' (SDTW) a sequence of measured features of a person can be recognized as a specific sign. These models are able to deal with differences in tempo, contrary to conventional methods of pattern recognition, which can only deal with a fixed set of features. However, one of the disadvantages of HMM and SDTW is that they assume that what is important for estimating time warping, is equally important to class recognition. Furthermore, they are based on the factorization of probabilities for different time points, preventing the modeling of dependencies between measurements at different time steps. For these reasons, we have proposed to separate time warping and classification into subsequent processing steps. Experiments show a significant improvement over HMM or SDTW alone. In practice, it is difficult to obtain many examples of signs from different persons, in order to train a recognition system. To make the system robust to small training sets, we let the system make use of sign classes that were already trained with many examples. Here, we assumed that, when a part of the new sign is very similar to a part of a learned sign, its variation can be modeled in the same way. With a single example as the training material, this generalizing system performed comparable to when five examples are used in the regular training method. From this thesis, it can be concluded that robustness is not only relevant for practical applications of computer vision, but also deserves a place in fundamental research. Combining vantage points from different disciplines, such as physics, machine learning, neuropsychology and human computer interaction, makes sure that all aspects of a computer vision process can be integrally taken into account. With this, more robust solutions can be obtained than with each of the disciplines separately.MediamaticsElectrical Engineering, Mathematics and Computer Scienc
Secretome of apoptotic cells causes cardioprotection and inhibits ventricular remodeling after acute myocardial infarction
No full textDer akute Myokardinfarkt gefolgt von linksventrikulärem Remodelling ist eine der Hauptursachen für die chronische Herzinsuffizienz in der westlichen Welt. Vorangegangene Untersuchungen zeigten, dass die Injektion apoptotischer Zellen im Tiermodell des Herzinfarkts die Infarktgröße signifikant reduzieren, die linksventrikuläre Funktion erhalten und das Einwandern regenerativer Zellpopulationen in die Ischämiezone fördern konnte. Ziel dieser Studie war, die diesen Effekten zugrundeliegenden Mechanismen zu entschlüsseln.
Ein besonderes Augenmerk wurde auf die Rolle parakriner Faktoren, die von apoptotischen Zellen sezerniert werden, gelegt.
Suspensionen apoptotischer Zellen wurden in einem Rattenmodell des akuten Herzinfarkts einerseits intravenös als auch intramyokardial injiziert. Morphologische und funktionelle Analysen wurden mittels Histologie, Planimetrie und Echokardiographie durchgeführt.
Die kardioprotektiven Eigenschaften von Zellkulturüberständen apoptotischer Zellen wurden in einem weiteren Rattenmodell des akuten Herzinfarkts mittels permanenter Gefäßligatur und ebenfalls in einem Großtiermodell mit anschließender Reperfusion evaluiert. Planimetrische und echokardiografische Analysen zeigten eine signifikante Reduktion der Infarktgröße mit geringeren Anzeichen von linksventrikulärer Dilatation und eine verbesserte linksventrikuläre Funktion in Tieren, denen Suspensionen apoptotischer Zeller injiziert wurden. In einer histologischen Auswertung zeigte sich, dass das kardiale Narbengewebe von therapierten Tieren eine weit höhere Akkumulation von elastischen Fasern aufwies.
Durch die ausschließliche Verabreichung von Zellkulturüberständen apoptischer Zellen konnte ebenfalls sowohl im Kleintier- als auch im Großtiermodell eine Reduktion der Infarktgröße und eine Verbesserung kardialer Funktionsparameter erzielt werden. In vitro Assays zeigten, dass humane Kardiomyozyten, die mit Zellkulturüberständen apoptotischer Zellen inkubiert wurden, eine Hochregulierung von anti-apoptotischen Mediatoren (Bcl-2, BAG1) und eine Aktivierung von kardioprotektiven Signalkaskaden (u.a. Akt, Erk1/2, CREB) zeigten. Diese Daten zeigen, dass die Verabreichung von apoptotischen Zellen beziehungsweise deren Zellkulturüberständen, zytoprotektive Signalwege in Kardiomyozyten induzieren und so den Infarktschaden reduzieren kann.Heart failure developing after acute myocardial ischaemia is a major cause of morbidity and mortality in the western world. In our previous study we showed that intravenous injection of apoptotic peripheral blood mononuclear cell (PBMC) suspensions preserved cardiac function in a rat acute myocardial infarction (AMI) model. Based on these results, we sought to investigate other ways of cell administration and analyzed the composition of the fibrotic scar tissue.
Moreover, we sought to study the effect of soluble factors secreted by apoptotic PBMC on ventricular remodelling after AMI.
Cell suspensions of apoptotic PBMC were injected intravenously (IV) or intramyocardially (IM) after experimental AMI in rats. The administration of cell culture medium or viable PBMC served as controls.
To study the effects of paracrine factors secreted by apoptotic cells, supernatants of irradiated PBMC were collected and injected intravenously after myocardial infarction in an experimental AMI rat model and in a porcine closed chest reperfused AMI model. Rats injected with suspensions of apoptotic PBMC (either intravenously or intramyocardially) evidenced a significant reduction of infarct dimensions and preservation of cardiac function. Histology showed that the ratio of elastic and collagenous fibres within the scar tissue was altered in a favourable fashion in rats injected with apoptotic cells compared to controls. The administration of supernatants of apoptotic PBMC resulted in a reduction of myocardial scar tissue formation in both the rat and the porcine model. In the large animal reperfused AMI model higher values of ejection fraction (57.0% vs. 40.5%, p<0.01), a better cardiac output (4.0 vs. 2.4 l/min., p<0.001) and a reduced extent of infarction size (12.6% vs. 6.9%, p<0.02) were found. In vitro experiments showed that exposure of primary human cardiac myocytes with paracrine factors secreted by apoptotic PBMC induced the activation of pro-survival signalling-cascades (AKT, Erk1/2, CREB) and increased anti-apoptotic gene products (Bcl-2, BAG1). Intravenous and intramyocardial injection of apoptotic cell suspensions preserved left ventricular function and altered the composition of cardiac scar tissue with increased expression of elastic fibres.
Intravenous infusion of cell culture supernatants of apoptotic PBMC attenuated myocardial remodelling in both experimental AMI animal models.submitted by Michael LichtenauerAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassung in dt. SpracheWien, Med. Univ., Diss., 2011OeBB(VLID)171540
Krankheitsmodifizierende Effekte eines Antikörper-basierten zielgerichteten Transfers von Interleukin-9 im präklinischen Modell der Pulmonalen Hypertonie
No full textPulmonale Hypertonie (PH) ist mit einem Umbau der pulmonalen Gefäße verbunden, dem pulmonalvaskulären Remodelling. Der gezielte Transfer von Interleukin-9 (IL9) über das Immunzytokin F8IL9 hat in einem Mausmodell der PH positive Effekte gezeigt. Ziel dieser Arbeit war es, zwei Immunzytokinformate (Single-Chain Fv und vollständiges IgG) zu vergleichen und potenzielle Zielzellen von IL9 zu identifizieren. Methoden: Das Monocrotalin-Mausmodell der PH (PH, n = 12) wurde verwendet, um die Behandlungseffekte von F8IL9F8 (n = 12) und F8IgGIL9 (n = 6) im Vergleich zu Kontrollen (n = 10), dem Endothelinrezeptorantagonisten Macitentan (MAC, n = 12) und Immunzytokinen mit irrelevanter Antigenspezifität (KSFIL9KSF, n = 12; KSFIgGIL9, n = 6) zu evaluieren und mögliche Zielzellen wie Mastzellen (MCs) oder regulatorische Zielzellen (Tregs) zu identifizieren und zu quantifizieren. Ergebnisse: Unbehandelte PH-Tiere zeigten signifikant erhöhte systolische Druckwerte im rechten Ventrikel und beeinträchtigte echokardiografische Parameter. Nur die mit F8IL9 behandelten Gruppen zeigten konsistent positive Effekte. So verringerte die Behandlung mit F8IL9F8 signifikant das Ausmaß der Lungengewebeschädigung. Zudem war die Zahl der Tregs im Lungengewebe der F8IL9-behandelten Tiere signifikant höher als in den Kontroll-, unbehandelten PH- und MAC-Gruppen (p < 0,05). Schlussfolgerung: Der gezielte IL9-Transfer zeigte positive Effekte in genanntem PH-Modell, wobei die IL9-induzierte Rekrutierung von Tregs eine zentrale Rolle in antiinflammatorischen und antiproliferativen Mechanismen spielen könnte und somit zu krankheitsmodifizierenden Effekten der Immunzytokintherapie beitragen könnte
Identifying interaction groups using the bluetooth proximity data of the Conflab dataset
No full textDetecting social interactions through wireless wearable Bluetooth devices is increasing in popularity. Devices use the signal strength to other detected devices to estimate the proximity between people and group them together based on the Dominant set algorithm. Dominant sets are a maximal clique of nodes with an edge-weight based on the affinity between the nodes. Nevertheless, the signal is heavily influenced by external factors, which increase in an crowded environment. This paper introduces three different noise reduction filters that try to detect the kind of noise and therefore improve the detection of surrounded devices. Further, this paper looks at the overall impact of proximity on the resulting RSSI values. Knowing this relationship helps to normalize the values and therefore eliminates the need to apply noise reduction. Using a dataset of 48 sensors recorded in a conference setting with a specific designed sensor the low frequency pass filter gets an accuracy score of 81.8 % with a cut-off frequency of 0.07 Hz. It performs best when considering a conversation window of 20 seconds. Here, only 2/3 of the detected groups has to coincide with the actual formed group at a specific timestamp. Furthermore, the orientation of the participants to each other has heavy influence on the resulting RSSI values and therefore a normalization based on only proximity cannot be done.CSE3000 Research ProjectComputer Science and Engineerin
A semi-automatic procedure for texturing of laser scanning point clouds with google streetview images
No full textWe introduce a method to texture 3D urban models with photographs that even works for Google Streetview images and can be done with currently available free software. This allows realistic texturing, even when it is not possible or cost-effective to (re)visit a scanned site to take textured scans or photographs. Mapping a photograph onto a 3D model requires knowledge of the intrinsic and extrinsic camera parameters. The common way to obtain intrinsic parameters of a camera is by taking several photographs of a calibration object with a priori known structure. The extra challenge of using images from a database such as Google Streetview, rather than your own photographs, is that it does not allow for any controlled calibration. To overcome this limitation, we propose to calibrate the panoramic viewer of Google Streetview using Structure from Motion (SfM) on any structure of which Google Streetview offers views from multiple angles. After this, the extrinsic parameters for any other view can be calculated from 3 or more tie points between the image from Google Streetview and a 3D model of the scene. These point correspondences can either be obtained automatically or selected by manual annotation. We demonstrate how this procedure provides realistic 3D urban models in an easy and effective way, by using it to texture a publicly available point cloud from a terrestrial laser scan made in Bremen, Germany, with a screenshot from Google Streetview, after estimating the focal length from views from Paris, France.Geoscience & Remote SensingCivil Engineering and Geoscience
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Die personnelle Beteiligung des Betriebsrats an der Einstellung,:Umgruppierung und Versetzung, nach dem Betriebsverfassungsgesetz vom 11.10.1952 -BGBL. I S.681 -
No full textPrime time for the sweet spot in timing of coronary invasive approach in patients with non-ST elevation myocardial infarction
No full textAcute coronary syndromes (ACS) continue to represent
a major cause of morbidity and mortality worldwide. In
the past decade data from the United States and Europe
reported decreased incidence of ST-elevation myocardial
infarction (STE-ACS) with an increase in non-ST-elevation
myocardial infarction (NSTE-ACS). As compared to
STE-ACS patients, during initial admission, NSTE-ACS
patients are at lower risk for death, but over time death
rates become comparable with a trend towards increased
mortality in the latter group. NSTE-ACS therefore
constitutes a challenge in cardiology
Die personnelle Beteiligung des Betriebsrats an der Einstellung,:Umgruppierung und Versetzung, nach dem Betriebsverfassungsgesetz vom 11.10.1952 -BGBL. I S.681 -
No full text- …
