Computerunterstützte Ganganalyse als neue Evaluationsmethode nach Rekonstruktion des Nervus medianus im Rattenmodell

Hintergrund: Die computerunterstützte Ganganalyse stellt eine gut etablierte und häufig verwendete Evaluationsmethode in verschiedenen murinen Modellen peripherer Nervenverletzungen der hinteren Extremität dar, segmentale Nervenverletzungen der vorderen Extremität wurden jedoch bisher noch nicht damit evaluiert. Die Zielsetzung dieser Arbeit bestand darin, zu untersuchen, ob es sich bei der computerunterstützten Ganganalyse um eine valide Methode handelt, um das Ausmaß der funktionellen Regeneration nach Neurotmesis des Nervus medianus im Rattenmodell zu bestimmen. Methoden: In zehn männlichen Lewis-Ratten erfolgte eine bilaterale Resektion von 7 mm des Nervus medianus. Auf der rechten Seite wurde der Nervus medianus anschließend mittels eines autologen Transplantats rekonstruiert. Linksseitig wurde der Defekt unüberbrückt belassen und als interne Negativkontrolle verwendet. Über einen zwölfwöchigen postoperativen Beobachtungszeitraum wurden die Ratten jeweils wöchentlich mittels Griffkraft-Test und zweiwöchentlich mittels CatWalk Ganganalyse nachuntersucht. Unmittelbar vor der Euthanasie der Tiere am Ende des Beobachtungszeitraums erfolgte außerdem die elektrophysiologische Untersuchung des rekonstruierten Nervus medianus und des vom ihm innervierten Musculus flexor digitorum superficialis. Die mittels CatWalk erhobenen Gangparameter wurden mit den Ergebnissen des Griffkraft-Tests korreliert. Zusätzlich erfolgte die Korrelationsanalyse der CatWalk Daten sowie der Ergebnisse der elektrophysiologischen Messungen mittels linearer Regression. Ergebnisse: Eine beginnende Regeneration der motorischen Fähigkeiten, ersichtlich anhand der Ergebnisse des Griffkraft-Tests, war ab der vierten postoperativen Woche feststellbar. Jedoch blieb die Griffkraft der Tiere bis einschließlich der sechsten postoperativen Wochen signifikant (p<0,01) unterhalb der präoperativ gemessenen Werte. Bezüglich der sensiblen Eigenschaften zeigte sich eine signifikante Erholung (p<0,05) des schmerzbezogenen Parameters der Belastungsdauer ab der achten postoperativen Woche. Die Fläche des Pfotenabdrucks auf der rechten Seite war ab der zehnten postoperativen Woche im Vergleich zur linken Seite signifikant (p<0,05) vergrößert. Gleich mehrere Gangparameter zeigten eine signifikante Korrelation (p<0,05) sowohl mit der durchschnittlichen als auch der maximalen Griffkraft. Zudem korrelierte der schmerzbezogenen Parameter Entlastungsindex signifikant (p<0,05) mit der Amplitude des Muskelsummenaktionspotentials des Musculus flexor digitorum superficialis. Diskussion: Anhand der vorliegenden Arbeit gelang der Nachweis, dass die computerunterstützte Ganganalyse eine valide komplementäre Evaluationsmethode der funktionellen Regeneration infolge der Rekonstruktion segmentaler Nervenverletzungen des Nervus medianus im Rattenmodell darstellt. Anhand von Parametern wie beispielsweise der Fläche des Pfotenabdrucks, der Belastungsdauer der Pfote oder des Entlastungsindexes kann die funktionelle Regeneration nach Nervenrekonstruktion mittels autologem Transplantat umfassend bestimmt werden. Zusätzlich ist es möglich, funktionelle Defizite, wie sie infolge der chronischen Denervierung der linken Vorderpfote auftraten, über den gesamten postoperativen Beobachtungszeitraum nachzuverfolgen. In Form der Ulnarabduktion der Vorderpfoten konnte außerdem ein Parameter identifiziert werden, anhand dessen die Regeneration motorischer Fähigkeiten allein mittels der Ganganalyse quantifiziert werden kann. Zusammengefasst handelt es sich bei der computerunterstützten Ganganalyse somit um eine valide Ergänzung der Methodiken zur Evaluation der funktionellen Regeneration im Nervus medianus Modell der Ratte. Jedoch gilt es in Folgestudien zu untersuchen ob, beziehungsweise inwieweit, die Ergebnisse der CatWalk Ganganalyse mit den Resultaten anderen Evaluationsmethoden, wie beispielsweise dem Semmes-Weinstein-Monofilament-Test korrelieren. Trotz der vielversprechenden Ergebnisse der vorliegenden Arbeit sollte die CatWalk Ganganalyse die anderen, bereits etablierten und bewährten Auswertungsmethoden der peripheren Nervenregenration nicht vollständig ersetzten. Vielmehr bietet der CatWalk die Möglichkeit, eine Vielzahl von Parametern zu erfassen, die Rückschlüsse auf die Regeneration sensibler und motorischen Nervenanteile erlauben und sollte daher einen Stellenwert als ergänzende Methode zur Evaluation der Nervenregeneration erhalten

Deep Learning Strategies for Industrial Surface Defect Detection Systems

Deep learning methods have proven to outperform traditional computer vision methods in various areas of image processing. However, the application of deep learning in industrial surface defect detection systems is challenging due to the insufficient amount of training data, the expensive data generation process, the small size, and the rare occurrence of surface defects. From literature and a polymer products manufacturing use case, we identify design requirements which reflect the aforementioned challenges. Addressing these, we conceptualize design principles and features informed by deep learning research. Finally, we instantiate and evaluate the gained design knowledge in the form of actionable guidelines and strategies based on an industrial surface defect detection use case. This article, therefore, contributes to academia as well as practice by (1) systematically identifying challenges for the industrial application of deep learning-based surface defect detection, (2) strategies to overcome these, and (3) an experimental case study assessing the strategies' applicability and usefulness

Translational evaluation of gait behavior in rodent models of arthritic disorders with the CatWalk device – a narrative review

Arthritic disorders have become one of the main contributors to the global burden of disease. Today, they are one of the leading causes of chronic pain and disability worldwide. Current therapies are incapable of treating pain sufficiently and preventing disease progression. The lack of understanding basic mechanisms underlying the initiation, maintenance and progression of arthritic disorders and related symptoms represent the major obstacle in the search for adequate treatments. For a long time, histological evaluation of joint pathology was the predominant outcome parameter in preclinical arthritis models. Nevertheless, quantification of pain and functional limitations analogs to arthritis related symptoms in humans is essential to enable bench to bedside translation and to evaluate the effectiveness of new treatment strategies. As the experience of pain and functional deficits are often associated with altered gait behavior, in the last decades, automated gait analysis has become a well-established tool for the quantitative evaluation of the sequalae of arthritic disorders in animal models. The purpose of this review is to provide a detailed overview on the current literature on the use of the CatWalk gait analysis system in rodent models of arthritic disorders, e.g., Osteoarthritis, Monoarthritis and Rheumatoid Arthritis. Special focus is put on the assessment and monitoring of pain-related behavior during the course of the disease. The capability of evaluating the effect of distinct treatment strategies and the future potential for the application of the CatWalk in rodent models of arthritic disorders is also addressed in this review. Finally, we discuss important consideration and provide recommendations on the use of the CatWalk in preclinical models of arthritic diseases

Concept and application of a computational vaccinology workflow

BACKGROUND : The last years have seen a renaissance of the vaccine area, driven by clinical needs in infectious diseases but also chronic diseases such as cancer and autoimmune disorders. Equally important are technological improvements involving nano-scale delivery platforms as well as third generation adjuvants. In parallel immunoinformatics routines have reached essential maturity for supporting central aspects in vaccinology going beyond prediction of antigenic determinants. On this basis computational vaccinology has emerged as a discipline aimed at ab-initio rational vaccine design.Here we present a computational workflow for implementing computational vaccinology covering aspects from vaccine target identification to functional characterization and epitope selection supported by a Systems Biology assessment of central aspects in host-pathogen interaction. We exemplify the procedures for Epstein Barr Virus (EBV), a clinically relevant pathogen causing chronic infection and suspected of triggering malignancies and autoimmune disorders. RESULTS : We introduce pBone/pView as a computational workflow supporting design and execution of immunoinformatics workflow modules, additionally involving aspects of results visualization, knowledge sharing and re-use. Specific elements of the workflow involve identification of vaccine targets in the realm of a Systems Biology assessment of host-pathogen interaction for identifying functionally relevant targets, as well as various methodologies for delineating B- and T-cell epitopes with particular emphasis on broad coverage of viral isolates as well as MHC alleles.Applying the workflow on EBV specifically proposes sequences from the viral proteins LMP2, EBNA2 and BALF4 as vaccine targets holding specific B- and T-cell epitopes promising broad strain and allele coverage. CONCLUSION : Based on advancements in the experimental assessment of genomes, transcriptomes and proteomes for both, pathogen and (human) host, the fundaments for rational design of vaccines have been laid out. In parallel, immunoinformatics modules have been designed and successfully applied for supporting specific aspects in vaccine design. Joining these advancements, further complemented by novel vaccine formulation and delivery aspects, have paved the way for implementing computational vaccinology for rational vaccine design tackling presently unmet vaccine challenges

Ranging and phase measurement for LISA

The LISA phase measurement system (PMS) will provide interferometric phase readout of the primary heterodyne signal at microcycle sensitivity, ranging measurements at sub-meter accuracy and data communication at rates of several kilobits per seconds. Our investigations are focused on inter-spacecraft laser ranging and data transfer for LISA using Direct Sequence Spread Spectrum (DS/SS) modulation onto the laser links. We present the setup of an optical experimental to test the levels of performance achievable with a single laser link as well as a new hardware prototype based on FPGA (Field Programmable Gate Array) processing to perform high-accuracy phase readout of the optical signal, ranging measurements, data communication and is suitable for clock noise demodulation and digital laser-phase locking

Visualizing the Unseen: Illustrating and Documenting Phantom Limb Sensations and Phantom Limb Pain With C.A.L.A.

Currently, there is neither a standardized mode for the documentation of phantom sensations and phantom limb pain, nor for their visualization as perceived by patients. We have therefore created a tool that allows for both, as well as for the quantification of the patient's visible and invisible body image. A first version provides the principal functions: (1) Adapting a 3D avatar for self-identification of the patient; (2) modeling the shape of the phantom limb; (3) adjusting the position of the phantom limb; (4) drawing pain and cramps directly onto the avatar; and (5) quantifying their respective intensities. Our tool (C.A.L.A.) was evaluated with 33 occupational therapists, physiotherapists, and other medical staff. Participants were presented with two cases in which the appearance and the position of the phantom had to be modeled and pain and cramps had to be drawn. The usability of the software was evaluated using the System Usability Scale and its functional range was evaluated using a self-developed questionnaire and semi-structured interview. In addition, our tool was evaluated on 22 patients with limb amputations. For each patient, body image as well as phantom sensation and pain were modeled to evaluate the software's functional scope. The accuracy of the created body image was evaluated using a self-developed questionnaire and semi-structured interview. Additionally, pain sensation was assessed using the SF-McGill Pain Questionnaire. The System Usability Scale reached a level of 81%, indicating high usability. Observing the participants, though, identified several operational difficulties. While the provided functions were considered useful by most participants, the semi-structured interviews revealed the need for an improved pain documentation component. In conclusion, our tool allows for an accurate visualization of phantom limbs and phantom limb sensations. It can be used as both a descriptive and quantitative documentation tool for analyzing and monitoring phantom limbs. Thus, it can help to bridge the gap between the therapist's conception and the patient's perception. Based on the collected requirements, an improved version with extended functionality will be developed

A Global Human Settlement Layer from optical high resolution imagery - Concept and first results

A general framework for processing of high and very-high resolution imagery for creating a Global Human Settlement Layer (GHSL) is presented together with a discussion on the results of the first operational test of the production workflow. The test involved the mapping of 24.3 millions of square kilometres of the Earth surface spread over four continents, corresponding to an estimated population of 1.3 billion of people in 2010. The resolution of the input image data ranges from 0.5 to 10 meters, collected by a heterogeneous set of platforms including satellite SPOT (2 and 5), CBERS-2B, RapidEye (2 and 4), WorldView (1 and 2), GeoEye-1, QuickBird-2, Ikonos-2, and airborne sensors. Several imaging modes were tested including panchromatic, multispectral and pan-sharpened images. A new fully automatic image information extraction, generalization and mosaic workflow is presented that is based on multiscale textural and morphological image features extraction. New image feature compression and optimization are introduced, together with new learning and classification techniques allowing for the processing of HR/VHR image data using low-resolution thematic layers as reference. A new systematic approach for quality control and validation allowing global spatial and thematic consistency checking is proposed and applied. The quality of the results are discussed by sensor, by band, by resolution, and eco-regions. Critical points, lessons learned and next steps are highlighted.JRC.G.2-Global security and crisis managemen

Seed architecture shapes embryo metabolism in oilseed rape

Constrained to develop within the seed, the plant embryo must adapt its shape and size to fit the space available. Here, we demonstrate how this adjustment shapes metabolism of photosynthetic embryo. Noninvasive NMR-based imaging of the developing oilseed rape (Brassica napus) seed illustrates that, following embryo bending, gradients in lipid concentration became established. These were correlated with the local photosynthetic electron transport rate and the accumulation of storage products. Experimentally induced changes in embryo morphology and/or light supply altered these gradients and were accompanied by alterations in both proteome and metabolome. Tissue-specific metabolic models predicted that the outer cotyledon and hypocotyl/radicle generate the bulk of plastidic reductant/ATP via photosynthesis, while the inner cotyledon, being enclosed by the outer cotyledon, is forced to grow essentially heterotrophically. Under field-relevant highlight conditions, major contribution of the ribulose-1,5-bisphosphate carboxylase/oxygenase-bypass to seed storage metabolism is predicted for the outer cotyledon and the hypocotyl/radicle only. Differences between in vitro- versus in planta-grown embryos suggest that metabolic heterogeneity of embryo is not observable by in vitro approaches. We conclude that in vivo metabolic fluxes are locally regulated and connected to seed architecture, driving the embryo toward an efficient use of available light and space

Spatiotemporal Differences in Gene Expression Between Motor and Sensory Autografts and Their Effect on Femoral Nerve Regeneration in the Rat

To improve the outcome after autologous nerve grafting in the clinic, it is important to understand the limiting variables such as distinct phenotypes of motor and sensory Schwann cells. This study investigated the properties of phenotypically different autografts in a 6 mm femoral nerve defect model in the rat, where the respective femoral branches distally of the inguinal bifurcation served as homotopic, or heterotopic autografts. Axonal regeneration and target reinnervation was analyzed by gait analysis, electrophysiology, and wet muscle mass analysis. We evaluated regeneration-associated gene expression between 5 days and 10 weeks after repair, in the autografts as well as the proximal, and distal segments of the femoral nerve using qRT-PCR. Furthermore we investigated expression patterns of phenotypically pure ventral and dorsal roots. We identified highly significant differences in gene expression of a variety of regeneration-associated genes along the central – peripheral axis in healthy femoral nerves. Phenotypically mismatched grafting resulted in altered spatiotemporal expression of neurotrophic factor BDNF, GDNF receptor GFRα1, cell adhesion molecules Cadm3, Cadm4, L1CAM, and proliferation associated Ki67. Although significantly higher quadriceps muscle mass following homotopic nerve grafting was measured, we did not observe differences in gait analysis, and electrophysiological parameters between treatment paradigms. Our study provides evidence for phenotypic commitment of autologous nerve grafts after injury and gives a conclusive overview of temporal expression of several important regeneration-associated genes after repair with sensory or motor graft