141 research outputs found
The converse of Kelly’s lemma and control-classes in graph reconstruction
No full textsummary:We prove a converse of the well-known Kelly’s Lemma. This motivates the introduction of the general notions of -table, -congruence and control-class
Markers dei processi proliferativi e riparativi e le molecole di adesione nella rigenerazione ossea.
No full textRedox Control of the Immune Response in the Hepatic Progenitor Cell Niche
No full textThe liver commonly self-regenerates by a proliferation of mature cell types. Nevertheless, in case of severe or protracted damage, the organ renewal is mediated by the hepatic progenitor cells (HPCs), adult progenitors capable of differentiating toward the biliary and the hepatocyte lineages. This regeneration process is determined by the formation of a stereotypical niche surrounding the emerging progenitors. The organization of the HPC niche microenvironment is crucial to drive biliary or hepatocyte regeneration. Furthermore, this is the site of a complex immunological activity mediated by several immune and non-immune cells. Indeed, several cytokines produced by monocytes, macrophages and T-lymphocytes may promote the activation of HPCs in the niche. On the other side, HPCs may produce pro-inflammatory cytokines induced by liver inflammation. The inflamed liver is characterized by high generation of reactive oxygen and nitrogen species, which in turn lead to the oxidation of macromolecules and the alteration of signaling pathways. Reactive species and redox signaling are involved in both the immunological and the adult stem cell regeneration processes. It is then conceivable that redox balance may finely regulate the immune response in the HPC niche, modulating the regeneration process and the immune activity of HPCs. In this perspective article, we summarize the current knowledge on the role of reactive species in the regulation of hepatic immunity, suggesting future research directions for the study of redox signaling on the immunomodulatory properties of HPCs
Aerial Video Surveillance System for Small-Scale UAV Environment Monitoring
No full textChange detection algorithms are commonly used to detect novelties for surveillance purposes in public and private places equipped by static or Pan-Tilt-Zoom (PTZ) cameras. Often, these techniques are also used as prerequisite to support more complex algorithms, including event recognition, object classification, person re-identification, and many others. With regard to small-scale Unmanned Aerial Vehicles (UAVs) at low-altitude, the change detection techniques require further investigation. In fact, most of the works currently available in the literature process video sequences acquired at very high-altitude for large-scale operations, such as vegetation monitoring, mapping of buildings, and so on. In a wide range of application contexts that require, for example, frequent monitoring or high spatial resolution for detecting small objects, video sequences acquired at high-altitude are not suitable. This paper presents a change detection system based on histogram equalization and RGB-Local Binary Pattern (RGB-LBP) operator for monitoring of wide areas by small-scale UAVs at low-altitude. Extensive experimental results show the robustness of the proposed pipeline. These latter were performed by using challenging video sequences of the public UAV Mosaicking and Change Detection (UMCD) dataset and measured a set of well-known statistical metrics. Finally, a performance analysis of the proposed algorithm is also provided
Low-Level feature detectors and descriptors for smart image and video analysis: a comparative study
No full textLocal feature detectors and descriptors (hereinafter extractors) play a key role in the modern computer vision. Their scope is to extract, from any image, a set of discriminative patterns (hereinafter keypoints) present on some parts of background and/or foreground elements of the image itself. A prerequisite of a wide range of practical applications (e.g., vehicle tracking, person re-identification) is the design and development of algorithms able to detect, recognize and track the same keypoints within a video sequence. Smart cameras can acquire images and videos of an interesting scenario according to different intrinsic (e.g., focus, iris) and extrinsic (e.g., pan, tilt, zoom) parameters. These parameters can make the recognition of a same keypoint between consecutive images a hard task when some critical factors such as scale, rotation and translation are present. The aim of this chapter is to provide a comparative study of the most used and popular low-level local feature extractors: SIFT, SURF, ORB, PHOG, WGCH, Haralick and A-KAZE. At first, the chapter starts by providing an overview of the different extractors referenced in a concrete case study to show their potentiality and usage. Afterwards, a comparison of the extractors is performed by considering the Freiburg-Berkeley Motion Segmentation (FBMS-59) dataset, a well-known video data collection widely used by the computer vision community. Starting from a default setting of the local feature extractors, the aim of the comparison is to discuss their behavior and robustness in terms of invariance with respect to the most important critical factors. The chapter also reports comparative considerations about one of the basic steps based on the feature extractors: the matching process. Finally, the chapter points out key considerations about the use of the discussed extractors in real application domains
A rare case of fibrosarcoma of the jaws in a 4-year-old male.
No full textA case of fibrosarcoma in a 4-year-old male child is reported. Primary fibrosarcomas of bone in the head and neck region are rare. The histological appearance of the tumour is related to its grade of differentiation. It could present a high level of cellularity and the amount of collagen is variable. The accepted treatment is radical surgery; however, metastases could occur in the lungs. This article is presented to highlight the rarity of fibrosarcomas in the jaws of children
Myofibroma/myofibromatosis is the most common fibrous proliferation of infancy and childhood.
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