Calibration standars of nuclear microprobes

El Micro-haz de iones Pesados (MiP) del laboratorio Tandar constituye un instrumento de características únicas en el país, pues puede proveer haces de iones pesados de dimensiones micrométricas acelerados hasta decenas de MeV de energía. La búsqueda de tamaños de haz más pequeños ha creado la necesidad de contar con estándares de calibración de elevada calidad de resolución. En el presente trabajo se desarrollaron los primeros prototipos para calibrar la focalización del haz: estructuras metálicas de cobre o niquel en forma de grilla con orificios cuadrados. Se emplearon dos métodos de fabricación. En el primero se utilizaron técnicas de fotolitografía convencional sobre un sustrato de silicio con foto-resina, mientras que en el segundo se utilizó el MiP para micro-mecanizar sustratos de Niobato de Litio (LiNbO3). En ambos casos se finalizó el proceso de fabricación del patrón con electrodeposición de cobre o níquel sobre la matriz desarrollada. Mediante la técnica fotolitográfica se fabricaron grillas de níquel que varían entre 130 y 180 mesh**. Mediante micro-mecanizado con el MiP se fabricaron grillas de cobre de entre 500 y 2000 mesh sobre sustratos de LiNbO3.The Micro-heavy ion beam (MiP) at Tandar’s Lab is a unique instrument in the country, as it can provide heavy ion beams at micrometer-scale accelerated to tens of MeV energy. The quest for smaller beam sizes has created the need for calibration standards of high resolution quality. In this paper we developed the first prototypes to calibrate the beam focusing: metal structures of copper or nickel shaped grid with square holes. We used two methods of manufacture. Were used in the first conventional photolithography techniques on a silicon substrate with photoresin while the second was used for micromachining with MiP substrates of lithium niobate (LiNbO3). In both cases the process for the manufacture was finished with electro-deposition of copper or nickel on the matrix developed. By photolithographic technique nickel grids were manufactured varying between 130 and 180 mesh. By MiP micromachining copper grids were produced between 500 and 2000 mesh on LiNbO3 substrates.Fil: Arena, S.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Faya, T.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Lell, J.. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; ArgentinaFil: Vega, N.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Davidson, Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nesprias, Francisco Jose Gabriel. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Debray, M.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentin

Optimizing Coronary Computed Tomography Angiography Using a Novel Deep Learning-Based Algorithm

Coronary computed tomography angiography (CCTA) is an essential part of the diagnosis of chronic coronary syndrome (CCS) in patients with low-to-intermediate pre-test probability. The minimum technical requirement is 64-row multidetector CT (64-MDCT), which is still frequently used, although it is prone to motion artifacts because of its limited temporal resolution and z-coverage. In this study, we evaluate the potential of a deep-learning-based motion correction algorithm (MCA) to eliminate these motion artifacts. 124 64-MDCT-acquired CCTA examinations with at least minor motion artifacts were included. Images were reconstructed using a conventional reconstruction algorithm (CA) and a MCA. Image quality (IQ), according to a 5-point Likert score, was evaluated per-segment, per-artery, and per-patient and was correlated with potentially disturbing factors (heart rate (HR), intra-cycle HR changes, BMI, age, and sex). Comparison was done by Wilcoxon-Signed-Rank test, and correlation by Spearman’s Rho. Per-patient, insufficient IQ decreased by 5.26%, and sufficient IQ increased by 9.66% with MCA. Per-artery, insufficient IQ of the right coronary artery (RCA) decreased by 18.18%, and sufficient IQ increased by 27.27%. Per-segment, insufficient IQ in segments 1 and 2 decreased by 11.51% and 24.78%, respectively, and sufficient IQ increased by 10.62% and 18.58%, respectively. Total artifacts per-artery decreased in the RCA from 3.11 ± 1.65 to 2.26 ± 1.52. HR dependence of RCA IQ decreased to intermediate correlation in images with MCA reconstruction. The applied MCA improves the IQ of 64-MDCT-acquired images and reduces the influence of HR on IQ, increasing 64-MDCT validity in the diagnosis of CCS

Die Computertomographie bei der Bildgebung von Kindern mit kongenitalen Herzvitien

Zusammenfassung: Kongenitale Herzfehler sind die häufigsten kongenitalen Fehlbildungen. Echokardiographie und Katheterangiographie gelten allgemein als Goldstandard zur Abklärung angeborener Herzerkrankungen. Die Magnetresonanztomographie ist aufgrund ihrer Fähigkeit, Herzvitien morphologisch und funktionell zu charakterisieren, als ein wichtiges ergänzendes Verfahren anzusehen. Durch mehr und mehr dosissparende Untersuchungsprotokolle der neuesten Gerätegenerationen und eine gleichzeitig bessere zeitliche und räumliche Auflösung findet die Computertomographie zunehmend Eingang in die Abklärung kongenitaler Herzfehler. In der präoperativen Planung und der postoperativen Kontrolle erlaubt sie eine übersichtliche Darstellung komplexer Fehlbildung nicht nur des Herzens, sondern auch der pulmonalvenösen und -arteriellen Zirkulation sowie des systemischen Kreislaufs. Dieser Beitrag gibt eine Übersicht über die technischen Aspekte der kardialen CT und die Anpassung des Untersuchungsprotokolls an die zu erwartende Pathologie und das Alter des Kindes. Zudem werden die Möglichkeiten und Limitationen der unterschiedlichen dosissparenden Protokolle erläuter

Determination of optimal core fissile loadings in the TREAT Upgrade reactor

The TREAT Upgrade (TU) reactor design is presently nearing completion. The reactor will be used to test LMFBR fuel under simulated accident conditions. The physics of the TU core is complicated by a number of factors related to the planned application of the facility. In this paper the design approach used to produce the core fissile loading spatial distribution needed to satisfy the requirement to test a number of different test clusters in various test loops in a transient operating mode is described. The TU core consists of a driver comprised of the pre Upgrade Zircaloy-clad TREAT fuel assemblies and a central converter region of new Inconel-clad fuel assemblies surrounding the test loop location. Separating the two concentric zones is a buffer zone that is made up of new Inconel clad assemblies operating at lower temperatures than the converter region

Orbital swelling as a first symptom in breast carcinoma diagnosis: a case report

<p>Abstract</p> <p>Introduction</p> <p>The frequency of intra-orbital metastasis in systemic cancer is a controversial topic. Of all metastatic tumors to the orbit of the eye, breast carcinoma is considered to be the most prevalent. Orbital findings typically present themselves after the diagnosis of the primary tumor, with an average delay of three to six years. In spite of that, this study reports a case in which orbital manifestation was the initial symptom in breast carcinoma diagnosis.</p> <p>Case presentation</p> <p>A 66-year-old Italian Caucasian woman presented with a swelling located on the lower orbit of her right eye.</p> <p>Conclusions</p> <p>Previous cases report orbital manifestations discovered secondary to breast cancer. This case demonstrates that orbital symptoms may be the primary presentation of the disease. Orbital metastasis originating from breast cancer predicts widespread metastatic disease in other organs. In the presence of an ambiguous infiltrative orbital process, diagnostic examination of the breast is recommended.</p

Microcystic adnexal carcinoma (MAC)-like squamous cell carcinoma as a differential diagnosis to Bell´s palsy: review of guidelines for refractory facial nerve palsy

Background Bell´s palsy is the most common cause of facial paralysis worldwide and the most common disorder of the cranial nerves. It is a diagnosis of exclusion, accounting for 60–75% of all acquired peripheral facial nerve palsies. Our case shows the first case of a microcystic adnexal carcinoma-like squamous cell carcinoma as a cause of facial nerve palsy. Case presentation The patient, a 70-year-old Caucasian male, experienced subsequent functional impairment of the trigeminal and the glossopharyngeal nerve about 1½ years after refractory facial nerve palsy. An extensive clinical work-up and tissue biopsy of the surrounding parotid gland tissue was not able to determine the cause of the paralysis. Primary infiltration of the facial nerve with subsequent spreading to the trigeminal and glossopharyngeal nerve via neuroanastomoses was suspected. After discussing options with the patient, the main stem of the facial nerve was resected to ascertain the diagnosis of MAC-like squamous cell carcinoma, and radiochemotherapy was subsequently started. Conclusion This case report shows that even rare neoplastic etiologies should be considered as a cause of refractory facial nerve palsy and that it is necessary to perform an extended diagnostic work-up to ascertain the diagnosis. This includes high-resolution MRI imaging and, as perilesional parotid biopsies might be inadequate for rare cases like ours, consideration of a direct nerve biopsy to establish the right diagnosis

Caracterización preliminar del Observatorio Central de Buenos Aires como Centro Regional de calibración de radiómetros solares

Fil: Nollas, Fernando Martín. Servicio Meteorológico Nacional. Dirección Nacional de Ciencia e Innovación en Productos y Servicios. Dirección Central de Monitoreo del Clima; Argentina.Fil: Lell, Julián. Servicio Meteorológico Nacional. Dirección Nacional de Ciencia e Innovación en Productos y Servicios. Dirección Central de Monitoreo del Clima; Argentina.Fil: Carbajal Benítez, Gerardo. Servicio Meteorológico Nacional. Dirección Nacional de Ciencia e Innovación en Productos y Servicios. Dirección Central de Monitoreo del Clima; Argentina.Fil: Marincovich, Giselle. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina.Fil: Barlasina, María Elena. Servicio Meteorológico Nacional. Dirección Nacional de Ciencia e Innovación en Productos y Servicios. Dirección Central de Monitoreo del Clima; Argentina.El Servicio Meteorológico Nacional (SMN) de Argentina opera una red solarimétrica en el territorio nacional, monitoreando parámetros radiativos como la radiación solar global, difusa, UVA, índice solar ultravioleta y radiación infrarroja atmosférica, entre otros. Debido a las inclemencias meteorológicas y la condición de intemperie a la que se encuentran los radiómetros solares, es necesaria una calibración periódica con la finalidad de brindarles trazabilidad y confiabilidad a sus mediciones. Para atender a las cuestiones relacionadas con trazabilidad, el SMN ha desarrollado el Laboratorio de Calibración a Intercomparación de Radiómetros Solares (LACIRS), el cual está encargado de realizar campañas de calibración e intercomparaciones con la finalidad de calibrar radiómetros solares con la mayor trazabilidad posible y de acuerdo a normativa establecida. Tal es así que el SMN fue designado por la Organización Meteorológica Mundial (OMM) como Centro Regional de Calibración de Radiómetros Solares (RCC) por su participación en las intercomparaciones internacionales de pirheliómetros que se realizan en el Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC) de Davos-Suiza. En este documento se presentan análisis y resultados preliminares acerca del comportamiento de diferentes parámetros meteorológicos con la finalidad de caracterizar el Observatorio Central de Buenos Aires como RCC.The Servicio Meteorologico Nacional (SMN) of Argentina operates a solarimetric network in the national territory, monitoring radiative parameters such as global, diffuse, UVA solar radiation, ultraviolet solar index and atmospheric infrared radiation, among others. Due to the inclement weather and the outdoor condition of the solar radiometers, a periodic calibration is necessary in order to provide traceability and reliability to their measurements. To address issues related to traceability, the SMN has developed the Solar Radiometer Calibration and Intercomparison Laboratory (LACIRS), which is in charge of carrying out calibration and intercomparison campaigns in order to calibrate solar radiometers with the greatest possible traceability and according to established regulations. So much so that the SMN was designated by the World Meteorological Organization (WMO) as a Regional Center for Calibration of Solar Radiometers (RCC) for its participation in the international intercomparisons of pyrheliometers that are carried out at the Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC) from Davos-Switzerland. This document presents preliminary analyzes and results about the behavior of different meteorological parameters in order to characterize the Central Observatory of Buenos Aires as RCC

A longitudinal study of allergy and intestinal helminth infections in semi urban and rural areas of Flores, Indonesia (ImmunoSPIN Study)

BACKGROUND: The prevalence of asthma and atopic disease has been reported to be low in low income countries, however helminth infections are likely to be high among these communities. The question of whether helminth infections play a role in allergic diseases can best be addressed by intervention studies. None of the studies so far have been based on a large scale placebo-controlled trial. METHOD/DESIGN: This study was designed to assess how intestinal helminth infections can influence the immune response and atopic and allergic disorders in children in Indonesia. The relations between allergic outcomes and infection and lifestyle factors will be addressed. This study was set up among school-age children in semi urban and rural areas, located in Ende District of Flores Island, Indonesia. A randomized placebo-controlled anthelmintic treatment trial to elucidate the impact of helminth infections on the prevalence of skin prick test (SPT) reactivity and symptoms of allergic diseases will be performed. The children living in these semi-urban and rural areas will be assessed for SPT to allergens before and after 1 and 2 years of treatment as the primary outcome of the study; the secondary outcome is symptoms (asthma and atopic dermatitis); while the tertiary outcome is immune responses (both antibody levels to allergens and cellular immune responses). DISCUSSION: The study will provide information on the influence of helminth infections and anthelmintic treatment on immune response, atopy and allergic disorders. TRIAL REGISTRATION: Current Controlled Trials ISRCTN: ISRCTN8383081