Dynamic Thermal Imaging for Intraoperative Monitoring of Neuronal Activity and Cortical Perfusion

Neurosurgery is a demanding medical discipline that requires a complex interplay of several neuroimaging techniques. This allows structural as well as functional information to be recovered and then visualized to the surgeon. In the case of tumor resections this approach allows more fine-grained differentiation of healthy and pathological tissue which positively influences the postoperative outcome as well as the patient's quality of life. In this work, we will discuss several approaches to establish thermal imaging as a novel neuroimaging technique to primarily visualize neural activity and perfusion state in case of ischaemic stroke. Both applications require novel methods for data-preprocessing, visualization, pattern recognition as well as regression analysis of intraoperative thermal imaging. Online multimodal integration of preoperative and intraoperative data is accomplished by a 2D-3D image registration and image fusion framework with an average accuracy of 2.46 mm. In navigated surgeries, the proposed framework generally provides all necessary tools to project intraoperative 2D imaging data onto preoperative 3D volumetric datasets like 3D MR or CT imaging. Additionally, a fast machine learning framework for the recognition of cortical NaCl rinsings will be discussed throughout this thesis. Hereby, the standardized quantification of tissue perfusion by means of an approximated heating model can be achieved. Classifying the parameters of these models yields a map of connected areas, for which we have shown that these areas correlate with the demarcation caused by an ischaemic stroke segmented in postoperative CT datasets. Finally, a semiparametric regression model has been developed for intraoperative neural activity monitoring of the somatosensory cortex by somatosensory evoked potentials. These results were correlated with neural activity of optical imaging. We found that thermal imaging yields comparable results, yet doesn't share the limitations of optical imaging. In this thesis we would like to emphasize that thermal imaging depicts a novel and valid tool for both intraoperative functional and structural neuroimaging

Seven year overview (2007-2013) of ethical transgressions by registered healthcare professionals in South Africa

A move has taken place internationally in the delivery and "consumption" of health care where if clients and patients (health care consumers) hold the opinion that the health care professionals/providers' behaviour has had a negative effect, impact or outcome on them, they may lodge a complaint with the relevant health professional regulatory body. Ethical transgressions of health care providers can generally be clustered into the following three categories: a) Competence and conduct with clients (e.g. abandonment, sexual intimacies, dishonesty, disclosure of information); b) Business practices (e.g. billing, reports, documentation); and c) Professional practice (e.g. referral upon termination, obtaining appropriate potential employment opportunities, nonprofessional relationships). The primary objective of this study was to analyse the ethical transgressions of registered members of the twelve professional boards in the Health Professions Council of South Africa (HPCSA) in the period 2007 to 2013. A mixed methods approach was followed in this study which specifically focused on a historical research approach. The results indicate that the boards with the highest number of transgressions per the registered practitioners were firstly the Medical and Dental practitioners, closely followed by the Optometry and Dispensing Opticians Board. The predominantly complaint made against members of both these boards was for fraudulent conduct (collectively totalling to 85% of all fraudulent cases during the period) and included actions such as charging for non-rendered services, issuing false statements and submitting fraudulent medical aid claims. Cognisance needs to be taken that the South African public will increasingly demand better services and that since they are being better informed via the media of their rights and have access to a broader database of knowledge (rightly or wrongly so the internet) practitioners' opinions will not necessarily be accepted outright and that they (the public) will challenge it accordingly. This raises the concern that practitioners need to take on the responsibility to communicate with their patients/clients in order to educate them and keep them informed.DHE

On Modelling Communication in Ubiquitous Computing Systems using Algebraic Higher Order Nets

Ubiquitous computing systems (UCSs) are designed to participate almostimperceptibly in everyday life. To ensure a solid operation, a UCS heavily depends on a reliable and efficient communication between its distributed computing components. Moreover components can join and leave the system at any time.In order to guarantee high quality systems, the use of models is inevitable especiallyat an early stage of the development process where models are the only possibilityto address a system which does not yet exist in reality. Petri nets and graph transformationsystems are established, theoretically well-founded concepts for modellingand analysing complex systems.This paper presents a formal approach for modelling core aspects of the communicationin UCSs by using Algebraic Higher Order Nets with Individual Tokens andgraph transformation. The approach is suitable to cover the different aspects ofcommunication and enables the analysis of specific properties. The approach and itssuitability are illustrated based on a running example. The feasibility of embeddingthe approach in a broader context of modelling is demonstrated in applying it to areal world system: the Living Place Hamburg

Implicit Neural Convolutional Kernels for Steerable CNNs

Steerable convolutional neural networks (CNNs) provide a general framework for building neural networks equivariant to translations and other transformations belonging to an origin-preserving group $G$, such as reflections and rotations. They rely on standard convolutions with $G$-steerable kernels obtained by analytically solving the group-specific equivariance constraint imposed onto the kernel space. As the solution is tailored to a particular group $G$, the implementation of a kernel basis does not generalize to other symmetry transformations, which complicates the development of group equivariant models. We propose using implicit neural representation via multi-layer perceptrons (MLPs) to parameterize $G$-steerable kernels. The resulting framework offers a simple and flexible way to implement Steerable CNNs and generalizes to any group $G$ for which a $G$-equivariant MLP can be built. We apply our method to point cloud (ModelNet-40) and molecular data (QM9) and demonstrate a significant improvement in performance compared to standard Steerable CNNs

Convolutional Neural Networks for Epileptic Seizure Prediction

Epilepsy is the most common neurological disorder and an accurate forecast of seizures would help to overcome the patient's uncertainty and helplessness. In this contribution, we present and discuss a novel methodology for the classification of intracranial electroencephalography (iEEG) for seizure prediction. Contrary to previous approaches, we categorically refrain from an extraction of hand-crafted features and use a convolutional neural network (CNN) topology instead for both the determination of suitable signal characteristics and the binary classification of preictal and interictal segments. Three different models have been evaluated on public datasets with long-term recordings from four dogs and three patients. Overall, our findings demonstrate the general applicability. In this work we discuss the strengths and limitations of our methodology.Comment: accepted for MLESP 201

Исследование структуры и физико-механических свойств спеченного антифрикционного материала системы Fe-Ti

In this article are presented results of research of structure and physicomechanical properties of the sintered material of Fe-Ti system. It is shown that this material possesses high tribotechnical characteristic on comparisons with sintered iron free. In the conclusion are offered parameters of receiving this material with high physicomechanical properties

Urban deformation monitoring in Bangkok metropolitan (Thailand) using permanent scatterer and differential interferometry techniques

Extensive ground water extraction has been identified as the principle cause of land subsidence in Bangkok and its vicinity. To mitigate major damages from large subsidence magnitudes the phenomenon must be well understood in this area. Up-to-date and reliable subsidence information is indispensable to develop this understanding. Conventionally, surface leveling has served as the primary method for measuring subsidence in Bangkok. But this is costly and time consuming. Differential SAR interferometry (DInSAR) can be an alternative means to obtain measurements of the surface displacement providing better resolution and comparable accuracy while being less time consuming. However, spatial and temporal decorrelation and atmospheric signal contributions in repeat-pass SAR interferometry often hamper the accurate measurement of surface displacements in SAR interferograms. The recently developed Permanent Scatterer (PS) technique invented by POLIMI researchers [1],[2],[3], overcomes these difficulties by interpreting time-series of interferometric phases at coherent point scatterers. In this study, we apply both DInSAR and PS techniques using two time-series of 17 and 11 ERS-SAR acquisitions for two partly overlapping image frames. This study is the first attempt to apply the PS technique to derive urban displacement information in Bangkok. We investigate the feasibility and reliability of using this technique with relatively few acquisitions and in a tropical location for deformation estimation. Using a linear deformation model and network algorithm, we estimate spatially varying displacement rates for the metropolitan area. Our first PS estimation results agree well with available ground leveling measurements

Measuring cellular traction forces on non-planar substrates

Animal cells use traction forces to sense the mechanics and geometry of their environment. Measuring these traction forces requires a workflow combining cell experiments, image processing and force reconstruction based on elasticity theory. Such procedures have been established before mainly for planar substrates, in which case one can use the Green's function formalism. Here we introduce a worksflow to measure traction forces of cardiac myofibroblasts on non-planar elastic substrates. Soft elastic substrates with a wave-like topology were micromolded from polydimethylsiloxane (PDMS) and fluorescent marker beads were distributed homogeneously in the substrate. Using feature vector based tracking of these marker beads, we first constructed a hexahedral mesh for the substrate. We then solved the direct elastic boundary volume problem on this mesh using the finite element method (FEM). Using data simulations, we show that the traction forces can be reconstructed from the substrate deformations by solving the corresponding inverse problem with a L1-norm for the residue and a L2-norm for 0th order Tikhonov regularization. Applying this procedure to the experimental data, we find that cardiac myofibroblast cells tend to align both their shapes and their forces with the long axis of the deformable wavy substrate.Comment: 34 pages, 9 figure

Professional consequence for dentists involved in unethical decision-making

ABSTRACT The previously gullible and apathetic South African public, generally speaking, is lately becoming increasingly rights-based sophisticated. Patients are no longer accepting inferior quality work and have become more knowledgeable especially regarding the expected skills and professional conduct of dentists. The present study examined archival material as published between 2007 and 2013 of penalties against ethical misconduct. It was found that the majority of ethical transgressions took place in urban settings and the most predominant transgression was charging for services not performed and submitting these claims to medical aids as well as performing sub-optimal interventions. Legally a practitioner who performs such acts may be held liable for the damage or injury suffered by the patient as a consequence of these acts, on the basis of negligence. Penalties imposed by the Health Professions Council of South Africa vary between 5,000 Rand and 15,000 Rand, as well as suspensions of between 9 to 12 months. It is doubtful that transgressors would change their behaviour in the light of the present Continuous Professional Development programmes where attendance is really the only prerequisite and not moral reflection. This study recommends that the Health Professions Council of South Africa need to re-evaluate the effectiveness of their ethical training programmes and adapt the model to incorporate more inclusive learning