Interactive Brain Tumor Segmentation with Inclusion Constraints

This thesis proposes an improved interactive brain tumor segmentation method based on graph cuts, which is an efficient global optimization framework for image segmentation, and star shape, which is a general segmentation shape prior with minimal user assistance. Our improvements lie in volume ballooning, compactness measure and inclusion constraints. Volume ballooning is incorporated to help to balloon segmentation for situations where the foreground and background have similar appearance models and changing relative weight between appearance model and smoothness term cannot help to achieve an accurate segmentation. We search different ballooning parameters for different slices since an appropriate ballooning force may vary between slices. As the evaluation for goodness of segmentation in parameter searching, two new compactness measures are introduced, ellipse fitting and convexity deviation. Ellipse fitting is a measure of compactness based on the deviation from an ellipse of best fit, which prefers segmentation with an ellipse shape. And convexity deviation is a more strict measure for preferring convex segmentation. It uses the number of convexity violation pixels as the measure for compactness. Inclusion constraints is added between slices to avoid side slice segmentation larger than the middle slice problem. The inclusion constraints consist of mask inclusion, which is implemented by an unary term in graph cuts, and pairwise inclusion, which is implemented by a pairwise term. Margin is allowed in inclusion so that the inclusion region is enlarged. With all these improvements, the final result is promising. The best performance for our dataset is 88% compared to the previous system that achieved 87%

A hybrid adaptive unscented Kalman filter algorithm

In order to overcome the limitation of the traditional adaptive Unscented Kalman Filtering (UKF) algorithm in noise covariance estimation for state and measurement, we propose a hybrid adaptive UKF algorithm based on combining Maximum a posteriori (MAP) criterion and Maximum likelihood (ML) criterion, in this paper. First, to prevent the actual noise covariance deviating from the true value which can lead to the state estimation error and arouse the filtering divergence, a real-time covariance matrices estimation algorithm based on hybrid MAP and ML is proposed for obtaining the statement and measurement noises covariance, respectively; and then, a balance equation the two kinds of covariance matrix is structured in this proposed to minimize the statement estimation error. Compared with the UKF based MAP and based ML, the proposed algorithm provides better convergence and stability

Automated Aspect Recommendation through Clustering-Based Fan-in Analysis

Identifying code implementing a crosscutting concern (CCC) automatically can benefit the maintainability and evolvability of the application. Although many approaches have been proposed to identify potential aspects, a lot of manual work is typically required before these candidates can be converted into refactorable aspects. In this paper, we propose a new aspect mining approach, called Clustering-Based Fan-in Analysis (CBFA), to rec-ommend aspect candidates in the form of method clusters, instead of single methods. CBFA uses a new lexical based clustering approach to identify method clusters and rank the clusters using a new ranking metric called cluster fan-in. Experiments on Linux and JHotDraw show that CBFA can provide accurate recommendations while improving aspect mining coverage significantly compared to other state-of-the-art mining approaches. 1

Loss of Prune in Circadian Cells Decreases the Amplitude of the Circadian Locomotor Rhythm in Drosophila

The circadian system, which has a period of about 24 h, is import for organismal health and fitness. The molecular circadian clock consists of feedback loops involving both transcription and translation, and proper function of the circadian system also requires communication among intracellular organelles. As important hubs for signaling in the cell, mitochondria integrate a variety of signals. Mitochondrial dysfunction and disruption of circadian rhythms are observed in neurodegenerative diseases and during aging. However, how mitochondrial dysfunction influences circadian rhythm is largely unknown. Here, we report that Drosophila prune (pn), which localizes to the mitochondrial matrix, most likely affects the function of certain clock neurons.Deletion of pn in flies caused decreased expression of mitochondrial transcription factor TFAM and reductions in levels of mitochondrial DNA, which resulted in mitochondrial dysfunction. Loss of pn decreased the amplitude of circadian rhythms.In addition, we showed that depletion of mtDNA by overexpression of a mitochondrially targeted restriction enzyme mitoXhoI also decreased the robustness of circadian rhythms. Our work demonstrates that pn is important for mitochondrial function thus involved in the regulation of circadian rhythms

Bisleuconothine A potentiates the effect of hyperbaric oxygen therapy against traumatic brain injury by enhancing P2X4 protein expressions

Purpose: To investigate the effect of bisleuconothine A (BA), alone and in combination with hyperbaric oxygen (HO), on traumatic brain injury (TBI) in rats. Methods: Traumatic brain injury (TBI) was induced by dropping a 200-g weight of steel on the left anterior frontal areas of Sprague-Dawley rats. The synergistic effect of BA and HO was determined by assessing neurological score, as well as parameters of oxidative stress and inflammation, expressions of P2X4 protein and other proteins, and levels of reactive oxygen species (ROS) in the brain tissues of TBI rats. Results: Neurological function score, levels of inflammatory mediators and oxidative stress parameters were significantly reduced in rats treated with BA alone, and in those treated with a combination of BA and HO, when compared with untreated TBI rats (p < 0.01). Moreover, treatment with BA alone, and BA-HO combination attenuated the altered protein expressions of P2X4, Akt, PI3K and TLR-4 in the TBI rats, and also upregulated the mRNA expression of P2X4 in the brain tissue, when compared with untreated TBI rats (p < 0.01). Conclusion: These results suggest that BA, when used alone or in combination with HO, reduces neuronal injury through upregulation of the protein expression of P2X4 in rats with traumatic brain injury. Thus, BA may be used clinically with HO therapy for the management of traumatic injury. Keywords: Bisleuconothine A, Hyperbaric oxygen, Neuronal injury, Oxidative stress, Inflammatory mediator

Photocatalytic oxidation of NOx under visible light on asphalt pavement surface

This work examines the potential use of heterogeneous photocatalysis as an innovative oxidation technology. The aim is to demonstrate that this technology can reduce the damaging effects of vehicle emissions by using nitrogen doped (N-doped) TiO2 as a photocatalyst immobilized above the asphalt road surface. In the study, the photocatalytic effectiveness and durability of N-doped TiO2 photocatalytic asphalt road material were assessed in both the laboratory and the field using direct and indirect measurement. The experimental results show that under visible light irradiation, N-doped TiO2 asphalt road material has a higher activity compared with pure TiO2 asphalt road material. The decontamination rate for NOx is approximately 27.6, 24.6, 16.3, and 13.8% under irradiation at light wavelengths of 330–420, 430–530, 470–570 and 590–680 nm, respectively. Results of the field test and prediction models suggest that the service life of N-doped TiO2 asphalt road material is approximately 13 months

Large Exchange Bias Effect and Coverage-Dependent Interfacial Coupling in CrI3/MnBi2Te4 van der Waals Heterostructures

Igniting interface magnetic ordering of magnetic topological insulators by building a van der Waals heterostructure can help to reveal novel quantum states and design functional devices. Here, we observe an interesting exchange bias effect, indicating successful interfacial magnetic coupling, in CrI3/MnBi2Te4 ferromagnetic insulator/antiferromagnetic topological insulator (FMI/AFM-TI) heterostructure devices. The devices originally exhibit a negative exchange bias field, which decays with increasing temperature and is unaffected by the back-gate voltage. When we change the device configuration to be half-covered by CrI3, the exchange bias becomes positive with a very large exchange bias field exceeding 300 mT. Such sensitive manipulation is explained by the competition between the FM and AFM coupling at the interface of CrI3 and MnBi2Te4, pointing to coverage-dependent interfacial magnetic interactions. Our work will facilitate the development of topological and antiferromagnetic devices