Patient-Specific Semi-Supervised Learning for Postoperative Brain Tumor Segmentation

In contrast to preoperative brain tumor segmentation, the problem of postoperative brain tumor segmentation has been rarely approached so far. We present a fully-automatic segmentation method using multimodal magnetic resonance image data and patient-specific semi-supervised learning. The idea behind our semi-supervised approach is to effectively fuse information from both pre- and postoperative image data of the same patient to improve segmentation of the postoperative image. We pose image segmentation as a classification problem and solve it by adopting a semi-supervised decision forest. The method is evaluated on a cohort of 10 high-grade glioma patients, with segmentation performance and computation time comparable or superior to a state-of-the-art brain tumor segmentation method. Moreover, our results confirm that the inclusion of preoperative MR images lead to a better performance regarding postoperative brain tumor segmentation.

De legibus Hebraeorum ritualibus, et earum rationibus : libri tres

authore Joanne Spencero

Fine-grained Indoor Tracking by Fusing Inertial Sensor and Physical Layer Information in WLANs

Indoor positioning has become an emerging research area because of huge commercial demands for location-based services in indoor environments. Channel State Information (CSI) as a fine-grained physical layer information has been recently proposed to achieve high positioning accuracy by using range-based methods, e.g., trilateration. In this work, we propose to fuse the CSI-based ranges and velocity estimated from inertial sensors by an enhanced particle filter to achieve highly accurate tracking. The algorithm relies on some enhanced ranging methods and further mitigates the remaining ranging errors by a weighting technique. Additionally, we provide an efficient method to estimate the velocity based on inertial sensors. The algorithms are designed in a network-based system, which uses rather cheap commercial devices as anchor nodes. We evaluate our system in a complex environment along three different moving paths. Our proposed tracking method can achieve 1:3m for mean accuracy and 2:2m for 90% accuracy, which is more accurate and stable than pedestrian dead reckoning and range-based positioning.

Polycapsulated Silica Core Nanoparticles for Laser Tissue Soldering

Introduction: Laser tissue fusion has a large potential for minimal invasive tissue fusion in different surgical specialties. We have developed a combined endovascular minimal invasive surgical technique to fuse blood vessels for bypass surgery. However, the main difficulty was to achieve reproducible results as the main tensile strength is a result of protein denaturation. We therefore aimed to develop a quantitative, reproducible tissue fusion using polycapsulated silica core nanoparticles containing indocyanine green (Si@PCL/ICG). Methods: In a first step we developed mesoporous indocyanine green (ICG) containing nanoparticles and assessed their heating profile. Furthermore the stability to light exposure and ICG degradation was measured. In a second phase Si@PCL/ICG nanoparticles for embedding into a biodegradeable implant was developed and characterized using differential scanning calomeritry technique (DSC). Results: ICG containing mesoporous silica nanoparticles showed a sufficient increase in temperature up to 80°C suitable for laser tissue fusion. However, long-term stability of ICG mesoporous nanoparticles is lost after 7 days of light exposure. In contrast Si@PCL/ICG nanoparticles demonstrated a strong heating capacity as well as a good DSC profile for laser tissue fusion and long-term stability of 3 weeks. Furthermore Si@PCL/ICG nanoparticles can be directly dispersed in spin-coated polycaprolactone polymer. Conclusion: Si@PCL/ICG nanoparticles have good long-term stability and polymer embedding properties suitable for laser tissue fusion.

OsteoMacs: Key players around bone biomaterials.

Osteal macrophages (OsteoMacs) are a special subtype of macrophage residing in bony tissues. Interesting findings from basic research have pointed to their vast and substantial roles in bone biology by demonstrating their key function in bone formation and remodeling. Despite these essential findings, much less information is available concerning their response to a variety of biomaterials used for bone regeneration with the majority of investigation primarily focused on their role during the foreign body reaction. With respect to biomaterials, it is well known that cells derived from the monocyte/macrophage lineage are one of the first cell types in contact with implanted biomaterials. Here they demonstrate extremely plastic phenotypes with the ability to differentiate towards classical M1 or M2 macrophages, or subsequently fuse into osteoclasts or multinucleated giant cells (MNGCs). These MNGCs have previously been characterized as foreign body giant cells and associated with biomaterial rejection, however more recently their phenotypes have been implicated with wound healing and tissue regeneration by studies demonstrating their expression of key M2 markers around biomaterials. With such contrasting hypotheses, it becomes essential to better understand their roles to improve the development of osteo-compatible and osteo-promotive biomaterials. This review article expresses the necessity to further study OsteoMacs and MNGCs to understand their function in bone biomaterial tissue integration including dental/orthopedic implants and bone grafting materials.

Fine-grained indoor positioning and tracking systems

Indoor positioning has attracted considerable attention for decades due to the increasing demands for location based services. In the past years, although numerous methods have been proposed for indoor positioning, it is still challenging to find a convincing solution that combines high positioning accuracy and ease of deployment. Radio-based indoor positioning has emerged as a dominant method due to its ubiquitousness, especially for WiFi. RSSI (Received Signal Strength Indicator) has been investigated in the area of indoor positioning for decades. However, it is prone to multipath propagation and hence fingerprinting has become the most commonly used method for indoor positioning using RSSI. The drawback of fingerprinting is that it requires intensive labour efforts to calibrate the radio map prior to experiments, which makes the deployment of the positioning system very time consuming. Using time information as another way for radio-based indoor positioning is challenged by time synchronization among anchor nodes and timestamp accuracy. Besides radio-based positioning methods, intensive research has been conducted to make use of inertial sensors for indoor tracking due to the fast developments of smartphones. However, these methods are normally prone to accumulative errors and might not be available for some applications, such as passive positioning. This thesis focuses on network-based indoor positioning and tracking systems, mainly for passive positioning, which does not require the participation of targets in the positioning process. To achieve high positioning accuracy, we work on some information of radio signals from physical-layer processing, such as timestamps and channel information. The contributions in this thesis can be divided into two parts: time-based positioning and channel information based positioning. First, for time-based indoor positioning (especially for narrow-band signals), we address challenges for compensating synchronization offsets among anchor nodes, designing timestamps with high resolution, and developing accurate positioning methods. Second, we work on range-based positioning methods with channel information to passively locate and track WiFi targets. Targeting less efforts for deployment, we work on range-based methods, which require much less calibration efforts than fingerprinting. By designing some novel enhanced methods for both ranging and positioning (including trilateration for stationary targets and particle filter for mobile targets), we are able to locate WiFi targets with high accuracy solely relying on radio signals and our proposed enhanced particle filter significantly outperforms the other commonly used range-based positioning algorithms, e.g., a traditional particle filter, extended Kalman filter and trilateration algorithms. In addition to using radio signals for passive positioning, we propose a second enhanced particle filter for active positioning to fuse inertial sensor and channel information to track indoor targets, which achieves higher tracking accuracy than tracking methods solely relying on either radio signals or inertial sensors.

Fine-grained Indoor Tracking by Fusing Inertial Sensor and Physical Layer Information in WLANs

Indoor positioning has become an emerging research area because of huge commercial demands for location-based services in indoor environments. Channel State Information (CSI) as fine-grained physical layer information has been recently proposed to achieve high positioning accuracy by using range based methods, e.g., trilateration. In this work, we propose to fuse the CSI-based ranging and velocity estimated from inertial sensors by an enhanced particle filter to achieve highly accurate tracking. The algorithm relies on some enhanced ranging methods and further mitigates the remaining ranging errors by a weighting technique. Additionally, we provide an efficient method to estimate the velocity based on inertial sensors. The algorithms are designed in a network-based system, which uses rather cheap commercial devices as anchor nodes. We evaluate our system in a complex environment along three different moving paths. Our proposed tracking method can achieve 1.3m for mean accuracy and 2.2m for 90% accuracy, which is more accurate and stable than pedestrian dead reckoning and range-based positioning.

The functions of pitx2 and Bmp signaling in craniofacial development

The formation of the vertebrate face is an extremely complex developmental process, which needs to coordinate the outgrowth of several facial primordia. Facial primordia are small buds made up of mesenchymal masses enclosed by an epithelial layer that surrounds the primitive mouth. The upper jaw is formed by the maxillary process, the lateral nasal process, and the frontonasal process while the mandibular process forms the lower jaw. Recent experiments using genetics in mice and bead implantation approaches have shown that the pitx2 homeobox gene and Bmp signaling play important roles in this complex developmental process. However, the molecular mechanisms underlying the function of pitx2 and Bmp in these events are still unclear. Here, we show that pitx2 is required for oral epithelium maintenance, and branchial arch signaling is pitx2 dosage sensitive by using pitx2 allelic combinations that encode varying levels of pitx2. Maintenance of fgf8 signaling requires only low pitx2 dosage while repression of Bmp signaling requires high pitx2 levels. Different incisor and molar phenotypes in low level pitx2 mutant embryos suggest a distinct requirement for pitx2 in tooth-type development. The results show that pitx2 is required for craniofacial muscle formation and expanded Bmp signaling results in excess bone formation in pitx2 mutant embryos. Fate-mapping studies show that ectopic bone results from excessive bone growth, instead of muscle transformation. Moreover, by using cre/loxp system we show that partial loss of Bmpr-IA in the facial primordia results in cleft lip/palate, abnormal teeth, ectopic teeth and tooth transformation. These phenotypes suggest that Bmp signaling has multiple functions during craniofacial development. The mutant palate shelves can fuse with each other when cultured in vitro, suggesting that cleft palate is secondary to the partial loss of Bmpr-IA. Furthermore, we prove that Bmp4, one of the ligands of Bmpr-IA, plays a role during lip fusion developmental process and partial loss of Bmp4 in the facial primordia results in the lip fusion delay. These results have provided insight to understand the complex signaling cascades that regulate craniofacial development. ^

El tercer espacio: cruce de culturas en la literatura de frontera

Favorecida por el proyecto económico y político de la globalización, es posible observar cómo, desde las últimas décadas del pasado siglo, se ha ido agudizando una tendencia a la hibridación que, si bien podríamos considerar casi innata de la condición humana, ha trascendido en nuestros días la mera enunciación retórica hasta llegar a impregnar casi todos los estratos de la cultura. En el campo de los estudios literarios este proceso de mixturación ha contribuido a generar una verdadera explosión de la llamada literatura de frontera, caracterizada no sólo por una mutación en las mentalidades de los sectores sociales y étnicos -desde los que se origina-, sino por profundos cambios en las mismas estructuras sociales, culturales y lingüísticas. Esta problemática pone en cuestión la homogeneidad y la esencialidad de la identidad cultural, pues es un fenómeno actual que nos remite, inevitablemente, a la complejidad de la identidad. Precisamente, podríamos hablar de deslizamientos que se van produciendo en los diferentes planos de las manifestaciones artísticas, tendiendo éstos a amalgamarse, a fundirse uno con otros, en un cruzamiento de líneas de fuga, de rupturas, que atraviesan ese nuevo espacio, el Tercer Espacio, donde los diferentes discursos se van hibridando unos con otros, rompiendo la imagen de unidad, la imagen unitaria y tradicional. Unidad que no existió nunca y que no puede existir de ningún modo, porque es una imagen acotada que se esfuma en el caótico tejido de lo vivo, en la conformación y evolución de la raza humana.

Sexualización de la historia reciente : Reflexiones y propuestas de enseñanza

El presente trabajo se propone realizar un abordaje teórico-práctico respecto a la necesidad de fusionar la historia reciente junto con la teoría de género. Se busca promover la construcción de un conocimiento del pasado donde se complejicen los procesos históricos a través de mirillas y sujetos históricos no contemplados anteriormente por la disciplina Historia. Esta propuesta permite cuestionar los relatos lineales de la historia y las narrativas que cristalizan y priorizan la enseñanza de los sucesos de la historia reciente, a través del "show del horror". Para aportar movilidad y dinamismo en estos campos, presentamos dos propuestas de trabajo para el aula donde se invita a pensar las relaciones de poder en clave de género

Sexualización de la historia reciente : Reflexiones y propuestas de enseñanza

El presente trabajo se propone realizar un abordaje teórico-práctico respecto a la necesidad de fusionar la historia reciente junto con la teoría de género. Se busca promover la construcción de un conocimiento del pasado donde se complejicen los procesos históricos a través de mirillas y sujetos históricos no contemplados anteriormente por la disciplina Historia. Esta propuesta permite cuestionar los relatos lineales de la historia y las narrativas que cristalizan y priorizan la enseñanza de los sucesos de la historia reciente, a través del "show del horror". Para aportar movilidad y dinamismo en estos campos, presentamos dos propuestas de trabajo para el aula donde se invita a pensar las relaciones de poder en clave de género

Sexualización de la historia reciente : Reflexiones y propuestas de enseñanza

El presente trabajo se propone realizar un abordaje teórico-práctico respecto a la necesidad de fusionar la historia reciente junto con la teoría de género. Se busca promover la construcción de un conocimiento del pasado donde se complejicen los procesos históricos a través de mirillas y sujetos históricos no contemplados anteriormente por la disciplina Historia. Esta propuesta permite cuestionar los relatos lineales de la historia y las narrativas que cristalizan y priorizan la enseñanza de los sucesos de la historia reciente, a través del "show del horror". Para aportar movilidad y dinamismo en estos campos, presentamos dos propuestas de trabajo para el aula donde se invita a pensar las relaciones de poder en clave de género

Discernment of bee pollen loads using computer vision and one-class classification techniques

In this paper, we propose a system for authenticating local bee pollen against fraudulent samples using image processing and classification techniques. Our system is based on the colour properties of bee pollen loads and the use of one-class classifiers to reject unknown pollen samples. The latter classification techniques allow us to tackle the major difficulty of the problem, the existence of many possible fraudulent pollen types. Also presented is a multi-classifier model with an ambiguity discovery process to fuse the output of the one-class classifiers. The method is validated by authenticating Spanish bee pollen types, the overall accuracy of the final system of being 94%. Therefore, the system is able to rapidly reject the non-local pollen samples with inexpensive hardware and without the need to send the product to the laboratory.

The strategies associated with the migration of networks to 4G

The networks need to provide higher speeds than those offered today. For it, considering that in the spectrum radio technologies is the scarcest resource in the development of these technologies and the new developments is essential to maximize the performance of bits per hertz transmitted. Long Term Evolution optimize spectral efficiency modulations with new air interface, and more advanced algorithms radius. These capabilities is the fact that LTE is an IPbased technology that enables end-to-end offer high transmission rates per user and very low latency, ie delay in the response times of the network around only 10 milliseconds, so you can offer any realtime application. LTE is the latest standard in mobile network technology and 3GPP ensure competitiveness in the future, may be considered a technology bridge between 3G networks - current 3.5G and future 4G networks, which are expected to reach speeds of up to 1G . LTE operators provide a simplified architecture but both robust, supporting services on IP technology. The objectives to be achieved through its implementation are ambitious, first users have a wide range of added services like capabilities that currently enjoys with residential broadband access at competitive prices, while the operator will have a network fully IP-based environment, reducing the complexity and cost of the same, which will give operators the opportunity to migrate to LTE directly. A major advantage of LTE is its ability to fuse with existing networks, ensuring interconnection with the same, increasing his current coverage and allowing a data connection established by a user in the environment continue when fade the coverage LTE. Moreover, the operator has the advantage of deploying network gradually, starting initially at areas of high demand for broadband services and expand progressively in line with this. RESUMEN. Las redes necesitan proporcionar velocidades mayores a las ofertadas a día de hoy. Para ello, teniendo en cuenta que en tecnologías radio el espectro es el recurso más escaso, en la evolución de estas tecnologías y en los nuevos desarrollos es esencial maximizar el rendimiento de bits por hercio transmitido. Long Term Evolution optimiza la eficiencia espectral con nuevas modulaciones en la interfaz aire, así como los algoritmos radio más avanzado. A estas capacidades se suma el hecho de que LTE es una tecnología basada en IP de extremo a extremo que permite ofrecer altas velocidades de transmisión por usuario y latencias muy bajas, es decir, retardos en los tiempos de respuesta de la red en torno a sólo 10 milisegundos, por lo que permite ofrecer cualquier tipo de aplicación en tiempo real. LTE es el último estándar en tecnología de redes móviles y asegurará la competitividad de 3GPP en el futuro, pudiendo ser considerada una tecnología puente entre las redes 3G – 3.5G actuales y las futuras redes 4G, de las que se esperan alcanzar velocidades de hasta 1G. LTE proporcionará a las operadoras una arquitectura simplificada pero robusta a la vez, soportando servicios sobre tecnología IP. Los objetivos que se persiguen con su implantación son ambiciosos, por una parte los usuarios dispondrá de una amplia oferta de servicios añadidos con capacidades similares a las que disfruta actualmente con accesos a banda ancha residencial y a precios competitivos, mientras que el operador dispondrá de una red basada en entorno totalmente IP, reduciendo la complejidad y el costo de la misma, lo que dará a las operadoras la oportunidad de migrar a LTE directamente. Una gran ventaja de LTE es su capacidad para fusionarse con las redes existentes, asegurando la interconexión con las mismas, aumentando su actual cobertura y permitiendo que una conexión de datos establecida por un usuario en el entorno LTE continúe cuando la cobertura LTE se desvanezca. Por otra parte el operador tiene la ventaja de desplegar la red LTE de forma gradual, comenzando inicialmente por las áreas de gran demanda de servicios de banda ancha y ampliarla progresivamente en función de ésta.

Registration and fusion of contrast-enhanced MRI myocardial substrate maps and X-ray angiograms

The aim of this work is to provide the necessary methods to register and fuse the endo-epicardial signal intensity (SI) maps extracted from contrast-enhanced magnetic resonance imaging (ceMRI) with X-ray coronary ngiograms using an intrinsic registrationbased algorithm to help pre-planning and guidance of catheterization procedures. Fusion of angiograms with SI maps was treated as a 2D-3D pose estimation, where each image point is projected to a Plücker line, and the screw representation for rigid motions is minimized using a gradient descent method. The resultant transformation is applied to the SI map that is then projected and fused on each angiogram. The proposed method was tested in clinical datasets from 6 patients with prior myocardial infarction. The registration procedure is optionally combined with an iterative closest point algorithm (ICP) that aligns the ventricular contours segmented from two ventriculograms.