ABSTRACT
Monte Carlo technique has been widely used as an important tool to develop new irradiation equipment, prototype medical equipment parts, and test methodologies for dosimetry. In this manuscript, we present a methodology to design a low power X-ray tube generator using the Geant4 Monte Carlo toolkit. The simulations were performed considering a large number of variables, namely, the material composition of the target track, the window thickness, and the air pressure of the X-ray tube. The X-ray production was simulated considering monoenergetic electron beams impinging on targets of tungsten and copper with incident kinetic energies ranging from 20 keV to 60 keV and initial divergences from 5° to 30°. For the polyenergetic emission, a conservative approach with Gaussian energy distribution was adopted. The analysis indicates that among the evaluated parameters, the incident kinetic energy, and the target material produced the most notable changes in the spectra shape and conversion efficiency (CE), significantly impacting the X-ray tube design. The studies provide a reliable methodology to explore general configurations for X-ray tube generators, defining the best geometry, material compositions, and thicknesses to be used on spectroscopy applications.
ABSTRACT
This study investigated the expression of the neonatal Fc receptor (FcRn) in maternal blood, cord blood and placental cells and determined IgG levels in maternal blood and cord blood from diabetic mothers. Peripheral blood, cord blood and placenta samples were collected from 26 mothers with normoglycaemia (non-diabetic, ND group) and 52 with hyperglycaemia (26 with mild gestational hyperglycaemia, MGH group, and 26 with type 2 diabetes mellitus, DM-2 group). Cells expressing CD19(+) and FcRn were identified by flow cytometry. Total IgG and its subclasses were quantified by ELISA. Maternal blood from DM-2 and cord blood from MGH exhibited a higher proportion of CD19(+) expression by B cells. DM-2 showed a lower proportion of CD19(+) cells in placenta. FcRn expression increased in cells from cord blood and placenta from MGH. Maternal blood, cord blood and placenta cells from DM-2 showed lower FcRn expression. Blood IgG levels were lower in DM-2, and cord blood IgG levels were higher in MGH. The highest levels of IgG4 were detected in the blood of hyperglycaemic mothers. The highest IgG3 and IgG4 levels in cord blood were detected in MGH, and the lowest IgG2 and IgG3 levels in DM-2. Maternal hyperglycaemia compromised placental transfer of IgG1, IgG3 and IgG4. The results suggest that regardless of hyperglycaemia degree, it decreases FcRn expression in placenta and blood cells and compromises the production and transfer of antibodies from maternal blood to newborns.
Subject(s)
Diabetes Mellitus, Type 2/immunology , Diabetes, Gestational/immunology , Histocompatibility Antigens Class I/immunology , Maternal-Fetal Exchange/immunology , Placenta/immunology , Receptors, Fc/immunology , Adult , Antigens, CD19/genetics , Antigens, CD19/immunology , Cross-Sectional Studies , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/pathology , Diabetes, Gestational/blood , Diabetes, Gestational/genetics , Diabetes, Gestational/pathology , Female , Fetal Blood/immunology , Fetus , Gene Expression , Histocompatibility Antigens Class I/genetics , Humans , Immunoglobulin G/blood , Immunoglobulin G/genetics , Infant, Newborn , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/pathology , Placenta/pathology , Pregnancy , Receptors, Fc/geneticsABSTRACT
Two clinical case reports of bullet embolism into the cardiovascular system are reported. The patient in the first case sustained a gunshot wound at the right clavicular area with embolism resulting in the right ventricle. In the second case, the patient received a projectile wound to the anterior right shoulder with eventual bullet embolism in the left iliac artery. In both cases, the bullets were removed successfully. Surgical intervention with the aid of extracorporeal circulation is recommended for similar cases.
ABSTRACT
Este trabalho e baseado em dois casos clinicos, em que projeteis seguiram caminhos inusitados, embolizando dentro do sistema cardiovascular. O primeiro paciente foi vitima de um ferimento por arma de fogo ao nivel da regiao infraclavicular direita O projetil atingiu a primeira costela, perfurou a veia subclavia direita e, sem transpassa-la, embolizou para a veia cava superior, auricula direita, vindo a se fixar no interior do ventriculo direito. Dai ele foi retirado cirurgicamente, com auxilio de circulacao extracorporea. O segundo paciente recebeu um tiro de revolver ao nivel do ombro direito. O projetil perfurou o pulmao direito, entrou numa veia pulmonar e embolizou para o atrio esquerdo, ventriculo esquerdo, aorta toracica e abdominal, vindo a parar ao nivel da arteria iliaca primitiva esquerda, de onde ele foi retirado cirurgicamente. Ambos os pacientes tiveram alta curados. Faz-se, concomitantemente, uma revisao da literatura
Subject(s)
Adult , Humans , Male , Female , Embolism , Thoracic Injuries , Wounds, GunshotABSTRACT
Os autores apresentam dois metodos praticos, que facilitam a execucao de colangiografias peroperatorias. Um deles consiste em clampear com um "bulddog"arterial o coledoco de modo a melhorar as imagens radiologicas das vias biliares intra-hepaticas. O outro utiliza duas sondas finas de Foley, que introduzidas pela coledocotomia e com orientacoes opostas possibilitam a visualizacao seletiva de arvore biliar e do coledoco terminal