The Hough Transform and the Impact of Chronic Leukemia on the Compact Bone Tissue from CT-Images Analysis

Computational analysis of X-ray Computed Tomography (CT) images allows the assessment of alteration of bone structure in adult patients with Advanced Chronic Lymphocytic Leukemia (ACLL), and may even offer a powerful tool to assess the development of the disease (prognostic potential). The crucial requirement for this kind of analysis is the application of a pattern recognition method able to accurately segment the intra-bone space in clinical CT images of the human skeleton. Our purpose is to show how this task can be accomplished by a procedure based on the use of the Hough transform technique for special families of algebraic curves. The dataset used for this study is composed of sixteen subjects including eight control subjects, one ACLL survivor, and seven ACLL victims. We apply the Hough transform approach to the set of CT images of appendicular bones for detecting the compact and trabecular bone contours by using ellipses, and we use the computed semi-axes values to infer information on bone alterations in the population affected by ACLL. The effectiveness of this method is proved against ground truth comparison. We show that features depending on the semi-axes values detect a statistically significant difference between the class of control subjects plus the ACLL survivor and the class of ACLL victims

Verrucous Melanoma Simulating Melanoacanthoma: Dermoscopic, Reflectance Confocal Microscopic and High-Definition Optical Coherence Tomography Presentation of a Rare Melanoma Variant

info:eu-repo/semantics/publishedVersio

Fast spectral fitting of hard X-ray bremsstrahlung from truncated power-law electron spectra

<p><b>Context:</b> Hard X-ray bremsstrahlung continuum spectra, such as from solar flares, are commonly described in terms of power-law fits, either to the photon spectra themselves or to the electron spectra responsible for them. In applications various approximate relations between electron and photon spectral indices are often used for energies both above and below electron low-energy cutoffs.</p> <p><b>Aims:</b> We examine the form of the exact relationships in various situations, and for various cross-sections, showing that empirical relations sometimes used can be highly misleading especially at energies below the low-energy cutoff, and consider how to improve fitting procedures.</p> <p><b>Methods:</b> We obtain expressions for photon spectra from single, double and truncated power-law electron spectra for a variety of cross-sections and for the thin and thick target models and simple analytic expressions for the non-relativistic Bethe-Heitler case.</p> <p><b>Results:</b> We show that below the low-energy cutoff Kramers and other constant spectral index forms commonly used are very poor approximations to accurate results, but that our analytical forms are a good match; and that above a low-energy cutoff, the Kramers and non-relativistic Bethe-Heitler results match reasonably well with results for up to energies around 100 keV.</p> <p><b>Conclusions:</b> Analytical forms of the non-relativistic Bethe-Heitler photon spectra from general power-law electron spectra are good match to exact results for both thin and thick targets and they enable much faster spectral fitting than evaluation of the full spectral integrations.</p&gt

Electron-Electron Bremsstrahlung Emission and the Inference of Electron Flux Spectra in Solar Flares

Although both electron-ion and electron-electron bremsstrahlung contribute to the hard X-ray emission from solar flares, the latter is normally ignored. Such an omission is not justified at electron (and photon) energies above $\sim 300$ keV, and inclusion of the additional electron-electron bremsstrahlung in general makes the electron spectrum required to produce a given hard X-ray spectrum steeper at high energies. Unlike electron-ion bremsstrahlung, electron-electron bremsstrahlung cannot produce photons of all energies up to the maximum electron energy involved. The maximum possible photon energy depends on the angle between the direction of the emitting electron and the emitted photon, and this suggests a diagnostic for an upper cutoff energy and/or for the degree of beaming of the accelerated electrons. We analyze the large event of January 17, 2005 observed by RHESSI and show that the upward break around 400 keV in the observed hard X-ray spectrum is naturally accounted for by the inclusion of electron-electron bremsstrahlung. Indeed, the mean source electron spectrum recovered through a regularized inversion of the hard X-ray spectrum, using a cross-section that includes both electron-ion and electron-electron terms, has a relatively constant spectral index $\delta$ over the range from electron kinetic energy $E = 200$ keV to $E = 1$ MeV. However, the level of detail discernible in the recovered electron spectrum is not sufficient to determine whether or not any upper cutoff energy exists.Comment: 7 pages, 5 figures, submitted to Astrophysical Journa

Dermatosis autoinmunes en caninos. Estudio retrospectivo

A retrospective study of canine skin samples diagnosed with autoimmune disease, admitted by the Veterinary Special Pathology Laboratory, was conducted between 2004 and 2016. Purposes of the study were to identify canine cases of skin lesions and to select those with a diagnosis of autoimmune disease. Autoimmune skin diseases were related to race, age, sex, type and anatomical location of the clinical lesions and, finally, different histopathological lesions characterizing each disease. Autoimmune diseases accounted for 2.07% of the total number of cases admitted in the study period, the most frequent being pemphigus foliaceus and discoid lupus erythematosus. The purebred dogs were more affected than the mixed animals, being the anatomical location of greater presentation the dorsal region of the nose (35.3%). Among the most frequent histopathological findings were pustules (54.1%), areas of dermo-epidermal separation (45.9%) and spongiosis (44.7%). Although the percentage of canines with autoimmune dermatosis is low, it is important to include differential diagnoses of the diseases that occur with pustules, papules, vesicles and inflammatory infiltrate in the dermoepidermal junction. Histopathology is a useful and accessible tool in that allows to diagnose these diseases.Se investigaron muestras de piel de caninos con diagnóstico de enfermedad autoinmune ingresadas entre los años 2004 y 2016 al Laboratorio de Patología Especial Veterinaria (FCV, La Plata, Argentina). Los objetivos fueron identificar casos de caninos con lesiones cutáneas y seleccionar aquéllos con diagnóstico de enfermedad autoinmune. También se propuso relacionar las dermatosis autoinmunes con la raza, edad, sexo, el tipo y la ubicación anatómica de las lesiones clínicas y, por ultimo, describir las diferentes lesiones histopatológicas que caracterizaron cada afección. Las enfermedades autoinmunes representaron el 2,07% del total de casos ingresados en el período de estudio, siendo las más frecuentes el pénfigo foliáceo y el lupus eritematoso discoide. Los caninos de raza pura fueron más afectados que los mestizos, siendo la región dorsal de la nariz la ubicación anatómica de mayor presentación (35,3%). Entre los hallazgos histopatológicos más reiterados se observaron pústulas (54,1%), áreas de separación dermoepidérmica (45,9%) y espongiosis (44,7%). Si bien el porcentaje de caninos con dermatosis autoinmunes es bajo, es importante incluirlas dentro de los diagnósticos diferenciales de las enfermedades que cursan con pústulas, pápulas, vesículas e infiltrado inflamatorio en la unión dermoepidérmica. La histopatología es una herramienta útil y relativamente accesible en nuestro medio, que permite arribar al diagnóstico de tales enfermedades

Regularized Electron Flux Spectra in the 2002 July 23 Solar Flare

By inverting the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) hard X-ray photon spectrum with the Tikhonov regularization algorithm, we infer the effective mean electron source spectrum for a time interval near the peak of the 2002 July 23 event. This inverse approach yields the smoothest electron flux spectrum consistent with the data while retaining real features, such as local minima, that cannot be found with forward model-fitting methods that involve only a few parameters. A significant dip in the recovered mean source electron spectrum near E = 55 keV is noted, and its significance briefly discussed

A group of three miRNAs can act as candidate circulating biomarkers in liquid biopsies from melanoma patients

Background: Staging of melanoma and follow up after melanoma diagnosis aims at predicting risk and detecting progression or recurrence at early stage, respectively in order to timely start and/or change treatment. Tumor thickness according to Breslow, status of the sentinel node and value of the lactate dehydrogenase (LDH) are well-established prognostic markers for metastatic risk, but reliable biomarkers identifying early recurrence or candidates who may benefit best from medical treatment are still warranted. Liquid biopsy has emerged to be a suitable method for identifying biomarkers for early cancer diagnosis, prognosis, therapeutic response prediction, and patient follow-up. Liquid biopsy is a blood- based non-invasive procedure that allows analyzing circulating analytes, including extracellular vesicles. Methods: In this study we have explored the use of 7 miRNAs, namely hsa- miR-149-3p, hsa-miR-150-5p, hsa-miR-21-5p, hsa-miR-200c-3p, hsa-miR-134- 5p, hsa-miR-144-3p and hsa-miR-221-3p in plasma exosomes to discriminate melanoma patients from controls without melanoma in a cohort of 92 individuals. Results and discussion: Our results showed that three out seven miRNAs, namely hsa-miR-200c-3p, hsa-miR-144-3p and hsa-miR-221-3p were differentially expressed in plasma-derived exosomes from melanoma patients and controls. Furthermore, the expression of the three miRNAs may be a promising ancillary tool as a melanoma biomarker, even for discriminating between nevi and melanoma

Regularized energy-dependent solar flare hard x-ray spectral index

The deduction from solar flare X-ray photon spectroscopic data of the energy dependent model-independent spectral index is considered as an inverse problem. Using the well developed regularization approach we analyze the energy dependency of spectral index for a high resolution energy spectrum provided by Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The regularization technique produces much smoother derivatives while avoiding additional errors typical of finite differences. It is shown that observations imply a spectral index varying significantly with energy, in a way that also varies with time as the flare progresses. The implications of these findings are discussed in the solar flare context.Comment: 13 pages; 5 figures, Solar Physics in pres

Flare forecasting and feature ranking using SDO/HMI data

We describe here the application of a machine learning method for flare forecasting using vectors of properties extracted from images provided by the Helioseismic and Magnetic Imager in the Solar Dynamics Observatory (SDO/HMI). We also discuss how the method can be used to quantitatively assess the impact of such properties on the prediction process