Hitting the right target : noninvasive localization of the subthalamic nucleus motor part for specific deep brain stimulation

Deep brain stimulation of the subthalamic nucleus (STN) has gained momentum as a therapy for advanced Parkinson’s disease. The stimulation effectively alleviates the patients’ typical motor symptoms on a long term, but can give rise to cognitive and psychiatric adverse effects as well. Based on primate studies, the STN has been divided into three functionally different parts, which were distinguished by their afferent and efferent connections. The largest part is the motor area, followed by an associative and a limbic area. The serious adverse effects on cognition and behavior occurring after deep brain stimulation are assumed to be caused by electrical current spread to the associative and limbic areas of the STN. Therefore, selective stimulation of the motor part of the STN seems crucial, both to obtain the best possible therapeutic effect on the motor symptoms and to minimize the debilitating effects on cognition and behavior. However, current medical imaging techniques do not yet facilitate the required accurate identification of the STN itself, let alone its different functional areas. The final target for DBS is still often adjusted using intraoperative electrophysiology. Therefore, in this thesis we aimed to improve imaging for deep brain stimulation using noninvasive MRI protocols, in order to identify the STN and its motor part. We studied the advantages and drawbacks of already available noninvasive methods to target the STN. This review did not lead to a straightforward conclusion; identification of the STN motor part remained an open question. In follow-up on this question, we investigated the possibility to distinguish the different functional STN parts based on their connectivity information. Three types of information were carefully analyzed in this thesis. First, we looked into the clustering of local diffusion information within the STN region. We visually inspected the complex diffusion profiles, derived from postmortem rat brain data with high angular resolution, and augmented this manual segmentation method using k-means and graph cuts clustering. Because the weighing of different orders of diffusion information in the traditionally used L2 norm on the orientation distribution functions (ODFs) remained an open issue, we developed a specialized distance measure, the so-called Sobolev norm. This norm does not only take into account the amplitudes of the diffusion profiles, but also their extrema. We showed it to perform better than the L2 norm on synthetic phantom data and real brain (thalamus) data. The research done on this topic facilitates better classification by clustering of gray matter structures in the (deep) brain. Secondly, we were the first to analyze the STN’s full structural connectivity, based on probabilistic fiber tracking in diffusion MRI data of healthy volunteers. The results correspond well to topical literature on STN projections. Furthermore, we assessed the structural connectivity per voxel of the STN seed region and discovered a gradient in connectivity to the premotor cortex within the STN. While going from the medial to the lateral part of the STN, the connectivity increases, confirming the expected lateral location of the STN motor part. Finally, the connectivity analysis produced evidence for the existence of a "hyperdirect" pathway between the motor cortex and the STN in humans, which is very useful for future research into stimulation targets. The results of these experiments indicate that it is possible to find the motor part of the STN as specific target for deep brain stimulation using structural connectivity information acquired in a noninvasive way. Third and last, we studied functional connectivity using resting state functional MRI data of healthy volunteers. The resulting significant clusters provided us with the first complete description of the STN’s resting state functional connectivity, which corresponds with the expectations based on available literature. Moreover, we performed a reverse regression procedure with the average time series signals in motor and limbic areas as principal regressors. The results were analyzed for each STN voxel separately and also showed mediolateral gradients in functional connectivity within the STN. The lateral STN part exhibited more motor connectivity, while the medial part seemed to be more functionally connected to limbic brain areas, as described in neuronal tracer studies. These results show that functional connectivity analysis also is a viable noninvasive method to find the motor part of the STN. The work on noninvasive MRI methods for identification of the STN and its functional parts, as presented in this thesis, thus contributes to future specific stimulation of the motor part of the STN for deep brain stimulation in patients with Parkinson’s disease. This may help to maximize the motor effects and minimize severe cognitive and psychiatric side effects

Automatic IVUS segmentation of atherosclerotic plaque with Stop & Go snake

Since the upturn of intravascular ultrasound (IVUS)as an imaging technique for the coronary artery system, much research has been done to simplify the complicated analysis of the resulting images. In this study, an attempt to develop an automatic tissue characterization algorithm for IVUS images was done. We concentrated on the segmentation of calcium and soft plaque, because these structures predict the extension and the vulnerability of the atherosclerotic disease, respectively. The first step in the procedure was the extraction of texture features like local binary patterns, co-occurrence matrices and Gabor filter banks. After dimensionality reduction, the resulting feature space was used for classification, constructing a likelihood map to represent different coronary plaques. The information in this map was organized using a recently developed geodesic snake formulation,the so-called Stop & Go snake. The novelty of our study lies in this last step, as it was the first time to apply the Stop & Go snake to segment IVUS images

Entwicklung eines Konzeptes für die Teilautomatisierung des Büchermagazins der Universitäts- und Landesbibliothek Düsseldorf

Dem Projekt zur Entwicklung eines Konzeptes für die Teilautomatisierung des Büchermagazins der ULB Düsseldorf liegt die Idee zu Grunde, eine an die Bedürfnisse und Anforderungen von Bibliotheken angepasste Lager-, Förder- und Kommissionierungstechnik einzusetzen, um den bibliotheksinternen Büchertransport effizienter zu gestalten und dabei das Bibliothekspersonal von körperlich belastenden Tätigkeiten zu entlasten. Parallel dazu könnte durch den Einsatz innovativer Buchlogistik die Bereitstellungszeit für Magazinbestellungen verkürzt werden. Auch die Ausdehnung des Services Magazinbestellungen auf die gesamten Öffnungszeiten der Zentralbibliothek würde realisierbar. Ob auch die Nutzung der Stellflächenkapazitäten des Büchermagazins optimiert würde, bleibt zu prüfen.The basic idea behind the project “Development of a concept of automation of the book stacks of the ULB Düsseldorf” is to organize the in-house book transport more efficiently using automatical storage and conveyer systems adapted to the requirements of libraries. The implementation of these systems facilitates the library staff’s work and reduces the burden of physically demanding work. Automatical storage and conveyer systems reduce delivery times and allow an extension of ordering services during the entire opening times. An additional objective to prove is to optimize space usage at the book stacks

Fachreferat heute : Analyse des Berufsbildes von Fachreferenten anhand von Stellenanzeigen der Jahre 2003 bis 2013

Dieses Projekt untersucht anhand von Stellenausschreibungen für Fachreferatspositionen, ob sich das darin zum Ausdruck kommende Berufsbild des Fachreferenten analog zu den stetig wachsenden und sich erweiternden Anforderungen der Bibliotheken geändert hat. Dazu wurden Stellenanzeigen in der Mailingliste Inetbib und der Zeitschrift Bibliotheksdienst über einen Zeitraum von zehn Jahren erfasst und ausgewertet. Neben formalen Kriterien wie den geforderten Ausbildungsvoraussetzungen von Fachreferenten wurden auch fachlich-inhaltliche Aspekte sowie geforderte Soft Skills einbezogen. Als Ergebnis der Untersuchung lässt sich festhalten, dass die Position des Fachreferenten zwar inhaltlich gleich geblieben ist, jedoch weitere Aufgaben hinzugekommen sind. Diese sind bedingt durch die dynamischen Veränderungen der Informationsinfrastruktur und die damit einhergehenden neuen Anforderungen an fachlich fundierte bibliothekarische Informationsdienstleistungen.This project examines job advertisements for field librarians in order to find out how the changing demands on this position have been reflected in the job descriptions. Therefore, employment ads for field librarian positions published on the mailing list Inetbib and the journal Bibliotheksdienst were collected and evaluated over a period of ten years. Besides formal criteria such as educational requirements and prior work experience, aspects such as professional qualification as well as soft skills were taken into consideration. As a result of the research it can be said that professional demands on field librarians have remained constant while the duties of this position have increased in scope and complexity due to the dynamic changes of the information infrastructure and the new demands on state-of-the-art information service activities in libraries

Eine Exkursion der gemeinsamen Baukommission von dbv und VDB nach Rotterdam und Umgebung

Wenn in den vergangenen Jahren die Anforderungen an neue Bibliotheksbauten diskutiert wurden, dann fielen zumeist Begriffe wie „Lernort“ oder „Dritter Ort“. Für die bauliche Entwicklung von Bibliotheken sind dies ohne Frage wichtige Themen. Die Arbeit der gemeinsamen Baukommission von dbv und VDB verdeutlichte jedoch den Bedarf, künftig auch weitere Aspekte näher zu betrachten. Initiativ dazu reiste die gemeinsame Baukommission im Oktober 2019 mit Kolleg*innen fast aller Bundesländer in die Niederlande, um dort unterschiedliche Bibliotheksneu- und -umbauten der letzten Jahre unter jeweils verschiedenen Fragestellungen zu untersuchen.When the requirements for new library buildings have been discussed in recent years, terms such as "place of learning" or "third place" have mostly been mentioned. These are undoubtedly important issues for the structural development of libraries. However, the work of the joint building commission of dbv and VDB made clear the need to take a closer look at other aspects in the future. On the initiative of this, the joint building commission traveled to the Netherlands in October 2019 with colleagues from almost all federal states in order to examine various new library buildings and renovations in recent years, each under a different set of questions

Eine Exkursion der gemeinsamen Baukommission von VDB und dbv nach Rotterdam und Umgebung

Wenn in den vergangenen Jahren die Anforderungen an neue Bibliotheksbauten diskutiert wurden, dann fielen zumeist Begriffe wie „Lernort“ oder „Dritter Ort“. Für die bauliche Entwicklung von Bibliotheken sind dies ohne Frage wichtige Themen. Die Arbeit der gemeinsamen Baukommission von dbv und VDB verdeutlichte jedoch den Bedarf, künftig auch weitere Aspekte näher zu betrachten. Initiativ dazu reiste die gemeinsame Baukommission im Oktober 2019 mit Kolleg*innen fast aller Bundesländer in die Niederlande, um dort unterschiedliche Bibliotheksneu- und -umbauten der letzten Jahre unter jeweils verschiedenen Fragestellungen zu untersuchen