An interpretable machine learning-based prediction model for risk of death for patients with ischemic stroke in intensive care unit / 南方医科大学学报

OBJECTIVE@#To construct an inherent interpretability machine learning model as an explainable boosting machine model (EBM) for predicting one-year risk of death in patients with severe ischemic stroke.@*METHODS@#We randomly divided the data of 2369 eligible patients with severe ischemic stroke in the MIMIC-Ⅳ(2.0) database, who were admitted in ICU in 2008 to 2019, into a training dataset (80%) and a test dataset (20%), and assessed the prognosis of the patients using the EBM model. The prediction performance of the model was evaluated by calculating the area under the receiver operating characteristic (AUC) curve. The calibration curve and Brier score were used to evaluate the degree of calibration of the model, and a decision curve was generated to assess the net clinical benefit.@*RESULTS@#The EBM model constructed in this study had good discrimination power, calibration and net benefit, with an AUC of 0.857 (95% CI: 0.831-0.887) for predicting prognosis of severe ischemic stroke. Calibration curve analysis showed that the standard curve of the EBM model was the closest to the ideal curve. Decision curve analysis showed that the model had the greatest net benefit rate at the prediction probability threshold of 0.10 to 0.80. The top 5 independent predictive variables based on the EBM model were age, SOFA score, mean heart rate, mechanical ventilation, and mean respiratory rate, whose significance scores ranged from 0.179 to 0.370.@*CONCLUSION@#This EBM model has a good performance for predicting the risk of death within one year in patients with severe ischemic stroke and allows clinicians to better understand the contributing factors of the patients' outcomes through the model interpretability.

A method for sensitivity analysis of deviation factor for geometric correction of cone-beam CT system / 南方医科大学学报

OBJECTIVE@#To propose a sensitivity test method for geometric correction position deviation of cone-beam CT systems.@*METHODS@#We proposed the definition of center deviation and its derivation. We analyzed the influence of the variation of the three-dimensional spatial center of the steel ball point, the projection center and the size of the steel ball point on the deviation of geometric parameters and the reconstructed image results by calculating the geometric correction parameters based on the Noo analytical method using the FDK reconstruction algorithm for image reconstruction.@*RESULTS@#The radius of the steel ball point was within 3 mm. The deviation of the center of the calibration parameter was within the order of magnitude and negligible. A 10% Gaussian perturbation of a single pixel in the 3D spatial coordinates of the steel ball point produced a deviation of about 3 pixel sizes, while the same Gaussian perturbation of the 2D projection coordinates of the steel ball point produced a deviation of about 2 pixel sizes.@*CONCLUSION@#The geometric correction is more sensitive to the deviation generated by the three-dimensional spatial coordinates of the steel ball point with limited sensitivity to the deviation generated by the two-dimensional projection coordinates of the steel ball point. The deviation sensitivity of a small diameter steel ball point can be ignored.

Use of Images and Clinical Experience to Calibrate Dental Surgeons for the Diagnosis of Molar Incisor Hypomineralization

ABSTRACT Objective: To evaluate an imaging protocol for use as a diagnostic and calibration tool for dentists before and after practical activity. Material and Methods: Thirty photos of children's teeth with or without changes in dental enamel were selected and evaluated by a group of experienced dentists previously calibrated to establish the diagnosis defined as the gold standard. After instructions, the images were shown to a group of postgraduate dentists for free identification of dental changes. Subsequently, a lecture on molar incisor hypomineralization (MIH) was carried out, and, at 14 days and all calibration was performed using the criteria previously. The retest was performed at 28 days. After experience in clinical activity in the following two weeks, the post-test was performed at 49 days. Data were analyzed using Cohen's kappa coefficient. Results: Theoretical learning on the subject showed low inter-examiner agreement when the diagnosis of defects was made from images obtained from intraoral photographs. After clinical practice, there was greater intra-examiner agreement. After theoretical training, dentists started to identify different types of enamel alteration, although with low agreement between them. Conclusion: Clinical experience in theoretical and imaging training favored the identification of defects. However, it is necessary to improve the protocol to establish a reliable and viable diagnostic method for calibration in MIH.

Análisis ajustado de la mortalidad operatoria en cirugía cardíaca de adultos en Uruguay; 14 años de aplicación y validación del EuroSCORE I ajustado por el Fondo Nacional de Recursos / Adjusted analysis of operative mortality in cardiac surgery of adults in Uruguay, 14 years of application and validation of EuroSCORE I by the Fondo Nacional de Recursos / Análise ajustada da mortalidade operatória em cirurgia cardíaca de adultos no Uruguai, 14 anos de aplicação e validação do EuroSCORE I pelo Fondo Nacional de Recursos

Introducción: la mortalidad posoperatoria ha sido el indicador principal de los resultados a corto y mediano plazo en la evaluación de la cirugía cardíaca. Una forma de analizar dicho evento es mediante los modelos de ajuste del riesgo que identifican variables que predicen su ocurrencia. Uno de los más utilizados es el EuroSCORE I que pro-porciona la probabilidad de morir de cada individuo y que está constituido por 18 variables de riesgo. Objetivos: presentar los resultados de la aplicación y la validación del modelo EuroSCORE I en Uruguay entre los años 2003 y 2020. Metodología: inicialmente se desarrolló una validación externa del EuroSCORE I en la población uruguaya adulta tomando como población de referencia la intervenida entre los años 2003 y 2006. Una vez que se validó el EuroSCORE I, este se aplicó prospectivamente durante los años 2007 al 2020 en su versión original y con el ajuste desarrollado con población del período 2003-2006. Resultados: la aplicación del modelo original encontró que hubo 5 años en los que la razón de mortalidad observada y esperada (MO/ME) fue significativamente mayor que 1. En el período 2007-2020 el EuroScore I no calibró en 6 oca-siones, y fue aplicada la versión ajustada en la evaluación de las instituciones de medicina altamente especializada. La aplicación del modelo ajustado mostró una buena calibración para el período 2007-2020, salvo en el año 2013, y mostró una buena discriminación (área bajo la curva ROC) en todo el período evaluado. Conclusiones: las escalas de riesgo son herramientas metodológicas y estadísticas que tienen gran utilidad para la toma de decisiones en salud. Este trabajo tiene como fortaleza el de presentar datos nacionales aplicando un modelo de riesgo ampliamente utilizado en todo el mundo, lo que nos permite comparar nuestros resultados con los obte-nidos a nivel internacional (EuroSCORE I logístico original) y, por otro lado, evaluar la performance comparativa interna a lo largo de un largo período de tiempo (EuroSCORE I logístico ajustado). Para el futuro resta el desafío de comparar estos resultados, ya sea con un modelo propio o con otros internacionales de elaboración más reciente.

Introduction: postoperative mortality has been the main indicator of short- and medium-term results in the eva luation of cardiac surgery. One way to analyze such outcomes is through risk adjustment models that identify varia bles that predict the occurrence. One of the most used is the EuroSCORE I, which provides the probability of death for each individual and is made up of 18 risk variables. Objectives: present the results of the application and validation of the EuroSCORE I model in Uruguay between 2003 and 2020. Methodology: initially, an external validation of the EuroSCORE I was developed in the Uruguayan adult popula tion, taking as reference population the intervened population between 2003 and 2006. Once the EuroSCORE I was validated, it was applied prospectively during the years 2007 to 2020 in its original version and with the adjustment developed with the population of the period 2003 to 2006. Results: the application of the original model found that there were 5 years during which the observed versus ex pected mortality ratio (OM/ME) was significantly greater than 1. In the period 2007 to 2020, the EuroScore I did not calibrate on 6 occasions, the adjusted version being applied in the evaluation of highly specialized medicine institu tions. The application of the adjusted model showed a good calibration for the period 2007-2020 except in the year 2013 and showed good discrimination (area under the ROC curve) throughout the evaluated period. Conclusions: risk scales are methodological and statistical tools that are very useful for decision-making in health care. This work has the strength of presenting national data applying a risk model widely used across the world, which allows it to be compare with results at an international level (original logistical Euroscore I) and, on the other hand, to evaluate the internal comparative performance over long period of time (adjusted logistic Euroscore I). Up next is the challenge of comparing these results either with our own model or with other more recent international ones.

Introdução: a mortalidade pós-operatória tem sido o principal indicador de resultados a curto e médio prazo na avaliação da cirurgia cardíaca. Uma forma de analisar esse evento é por meio de modelos de ajuste de risco que identificam variáveis que predizem a ocorrência do evento. Um dos mais utilizados é o EuroSCORE I, que fornece a probabilidade de morrer para cada indivíduo e é composto por 18 variáveis de risco. Objetivos: apresentar os resultados da aplicação e validação do modelo EuroSCORE I no Uruguai entre os anos de 2003 e 2020. Metodologia: inicialmente, foi realizada uma validação externa do EuroSCORE I na população uruguaia adulta, tomando como referência a população operada entre 2003 e 2006. Uma vez validado o EuroSCORE I, foi aplicado prospectivamente durante os anos de 2007 a 2020 em sua versão original e com o ajuste desenvolvido com a popu lação do período de 2003 a 2006. Resultados: a aplicação do modelo original constatou que houve 5 anos em que a razão de mortalidade observada versus esperada (MO/ME) foi significativamente maior que 1. No período de 2007 a 2020, o EuroScore I não calibrou em 6 ocasiões, sendo a versão ajustada aplicada na avaliação de instituições médicas altamente especializadas. A aplicação do modelo ajustado mostrou uma boa calibração para o período 2007-2020 exceto no ano de 2013 e apre sentou boa discriminação (área sob a curva ROC) em todo o período avaliado. Conclusões: as escalas de risco são ferramentas metodológicas e estatísticas muito úteis para a tomada de decisões em saúde. O ponto forte deste trabalho é apresentar dados nacionais aplicando um modelo de risco amplamente uti lizado em todo o mundo, que permite comparar com resultados a nível internacional (original Logistic Euroscore I) e, por outro lado, avaliar o comparativo interno desempenho durante um longo período de tempo (Euroscore Logístico I ajustado). Para o futuro, fica o desafio de comparar esses resultados, seja com um modelo próprio ou com outros internacionais de elaboração mais recente.

Study on the difference of high frequency dielectric properties of biological tissues measured by air and packed coaxial probe / 生物医学工程学杂志

In this paper, the differences between air probe and filled probe for measuring high-frequency dielectric properties of biological tissues are investigated based on the equivalent circuit model to provide a reference for the methodology of high-frequency measurement of biological tissue dielectric properties. Two types of probes were used to measure different concentrations of NaCl solution in the frequency band of 100 MHz-2 GHz. The results showed that the accuracy and reliability of the calculated results of the air probe were lower than that of the filled probe, especially the dielectric coefficient of the measured material, and the higher the concentration of NaCl solution, the higher the error. By laminating the probe terminal, liquid intrusion could be prevented, to a certain extent, to improve the accuracy of measurement. However, as the frequency decreased, the influence of the film on the measurement increased and the measurement accuracy decreased. The results of the study show that the air probe, despite its simple dimensional design and easy calibration, differs from the conventional equivalent circuit model in actual measurements, and the model needs to be re-corrected for actual use. The filled probe matches the equivalent circuit model better, and therefore has better measurement accuracy and reliability.

Keloid nomogram prediction model based on weighted gene co-expression network analysis and machine learning / 生物医学工程学杂志

Keloids are benign skin tumors resulting from the excessive proliferation of connective tissue in wound skin. Precise prediction of keloid risk in trauma patients and timely early diagnosis are of paramount importance for in-depth keloid management and control of its progression. This study analyzed four keloid datasets in the high-throughput gene expression omnibus (GEO) database, identified diagnostic markers for keloids, and established a nomogram prediction model. Initially, 37 core protein-encoding genes were selected through weighted gene co-expression network analysis (WGCNA), differential expression analysis, and the centrality algorithm of the protein-protein interaction network. Subsequently, two machine learning algorithms including the least absolute shrinkage and selection operator (LASSO) and the support vector machine-recursive feature elimination (SVM-RFE) were used to further screen out four diagnostic markers with the highest predictive power for keloids, which included hepatocyte growth factor (HGF), syndecan-4 (SDC4), ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2), and Rho family guanosine triphophatase 3 (RND3). Potential biological pathways involved were explored through gene set enrichment analysis (GSEA) of single-gene. Finally, univariate and multivariate logistic regression analyses of diagnostic markers were performed, and a nomogram prediction model was constructed. Internal and external validations revealed that the calibration curve of this model closely approximates the ideal curve, the decision curve is superior to other strategies, and the area under the receiver operating characteristic curve is higher than the control model (with optimal cutoff value of 0.588). This indicates that the model possesses high calibration, clinical benefit rate, and predictive power, and is promising to provide effective early means for clinical diagnosis.

Discrete element simulation study of mixing process of Guizhi Fuling Capsules: parameter calibration / 中国中药杂志

The mixing process is a critical link in the formation of oral solid preparations of traditional Chinese medicine. This paper took the extract powder of Guizhi Fuling Capsules and Paeonol powder as research objects. The angle of repose, loose packing density, and particle size of the two powders were measured to calibrate discrete element simulation parameters for the mixing process. The discrete element method was used to calibrate the simulated solid density of Paeonol powder and extract powder of Guizhi Fuling Capsules based on the Hertz-Mindlin with JKR V2 contact model and particle scaling. The Plackett-Burman experimental design was used to screen out the critical contact parameters that had a significant effect on the simulation of the angle of repose. The regression model between the critical contact parameters and the simulated angle of repose was established by the Box-Behnken experimental design, and the critical contact parameters of each powder were optimized based on the regression model. The best combination of critical contact parameters of the extract powder of Guizhi Fuling Capsules was found to be 0.51 for particle-particle static friction coefficient, 0.31 for particle-particle rolling friction coefficient, and 0.64 for particle-stainless steel static friction coefficient. For Paeonol powder, the best combination of critical contact parameters was 0.4 for particle-particle static friction coefficient and 0.19 for particle-particle rolling friction coefficient. The best combination of contact parameters between Paeonol powder and extract powder of Guizhi Fuling Capsules was 0.27 for collision recovery coefficient, 0.49 for static friction coefficient, and 0.38 for rolling friction coefficient. The verification results show that the relative error between the simulated value and the measured value of the angle of repose of the two single powders is less than 1%, while the relative error between the simulated value and the measured value of the angle of repose of the mixed powder with a mass ratio of 1∶1 is less than 4%. These research results provide reliable physical property simulation data for the mixed simulation experiment of extract powder of Guizhi Fuling Capsules and Paeonol powder.

Uncalibrated Positioning Method for Puncture Robots Based on Optical Navigation / 中国医疗器械杂志

Robotic puncture system has been widely used in modern minimally invasive surgery, which usually uses hand-eye calibration to calculate the spatial relationship between the robot and the optical tracking system. However, the hand-eye calibration process is time-consuming and sensitive to environmental changes, which makes it difficult to guarantee the puncture accuracy of the robot. This study proposes an uncalibrated positioning method for puncture robot based on optical navigation. The method divides the target path positioning into two stages, angle positioning and position positioning, and designs angle image features and position image features respectively. The corresponding image Jacobian matrix is constructed based on the image features and updated by online estimation with a cubature Kalman filter to drive the robot to perform target path localization. The target path positioning results show that the method is more accurate than the traditional hand-eye calibration method and saves significant preoperative preparation time by eliminating the need for calibration.

Research and Design of Calibration Device for Medical Test Lung / 中国医疗器械杂志

In order to solve the problems of quality control and traceability of medical test lung for meeting the calibration conditions of JJF 1234-2018 Calibration Specification for Ventilators, the calibration device and method are researched for compliance and airway resistance of medical test lung in this paper. A calibration device for medical test lung is designed using constant volume active piston technology to simulate human breathing. Through comparison experiment, the deviation between this device and the similar foreign device can be found. The deviation is lower than 0.4% for lung compliance and lower than 0.7% for airway resistance. The calibration of lung compliance and airway resistance can be completed by this device. This device has a clear and complete traceability path to ensure quality control from the source. The calibration of ventilator is improved. This paper provides a reference for related metrology departments and medical institutions to study on quality inspection of respiratory medical instruments.

Comparison of prediction ability of two extended Cox models in nonlinear survival data analysis / 南方医科大学学报

OBJECTIVE@#To compare the predictive ability of two extended Cox models in nonlinear survival data analysis.@*METHODS@#Through Monte Carlo simulation and empirical study and with the conventional Cox Proportional Hazards model and Random Survival Forests as the reference models, we compared restricted cubic spline Cox model (Cox_RCS) and DeepSurv neural network Cox model (Cox_DNN) for their prediction ability in nonlinear survival data analysis. Concordance index was used to evaluate the differentiation of the prediction results (a larger concordance index indicates a better prediction ability of the model). Integrated Brier Score was used to evaluate the calibration degree of the prediction (a smaller index indicates a better prediction ability).@*RESULTS@#For data that met requirement of the proportion risk, the Cox_RCS model had the best prediction ability regardless of the sample size or deletion rate. For data that failed to meet the proportion risk, the prediction ability of Cox_DNN was optimal for a large sample size (≥500) with a low deletion (< 40%); the prediction ability of Cox_RCS was superior to those of other models in all other scenarios. For example data, the Cox_RCS model showed the best performance.@*CONCLUSION@#In analysis of nonlinear low maintenance data, Cox_RCS and Cox_DNN have their respective advantages and disadvantages in prediction. The conventional survival analysis methods are not inferior to machine learning or deep learning methods under certain conditions.

Normatização da Bateria de Provas de Raciocínio (BPR-5) usando a Teoria de Resposta ao Item / Standardization of the Reasoning Tests Battery (BPR-5) using Item Response Theory / Estandarización de la Batería de Pruebas de Razonamiento (BPR-5) usando la teoría de respuesta al ítem

A Bateria de Provas de Raciocínio (BPR-5) é um instrumento bastante utilizado para avaliação da inteligência no Brasil, possuindo três formas: infantil (1º ao 6º ano do Ensino Fundamental), Forma A (7º ao 9º ano do Ensino Fundamental) e Forma B (Ensino Médio e Superior). Visando a possibilidade de comparar os resultados entre sujeitos que respondem a formas diferentes, o presente estudo objetivou: (a) calibrar os itens das três formas pelo modelo de Rasch, realizando a equalização por itens comuns de modo a obter uma escala equiparável para as três formas, (b) atualizar as normas expandindo a representatividade das amostras e produzindo-se normas para diferentes combinações de idade, escolaridade e sexo, (c) descrever padrões de desenvolvimento da inteligência a partir da escala, comum, produzida entre 6 e 52 anos. Dois estudos foram relatados, o primeiro sobre a calibração dos parâmetros segundo o modelo de Rasch indicando um bom ajuste ao modelo. O segundo estudo exemplificou a utilização de regressão múltipla para criação de normas para testes psicológicos, considerando as variáveis idade, escolaridade e sexo como preditoras dos escores na BPR-5. Essas três variáveis tiveram efeitos significativos explicando 8% (Raciocínio Abstrato), 13% (Raciocínio Verbal), 12% (Raciocínio Espacial), 8% (Raciocínio Numérico) e 22% (Raciocínio Mecânico).(AU)

The Reasoning Tests Battery (BPR-5) is widely used in Brazil for the assessment of intelligence. It has three different forms: children (1st to 6th grade of elementary school), Form A (7th to 9th grade of elementary school) and Form B (high school and higher education). This study describes the steps followed to create a common metric across the forms. It aimed to: (a) calibrate the items of the three forms using Rasch model, link items and equate subjects' scores across forms using the anchoring of common items method, (b) update the norms by expanding the representativeness of the samples by producing norms for different combinations of age, education and sex, and (c) describe the developmental patterns of the BPR-5 subtests across a wide age range, from 6 to 52 years. We present two studies, the first reporting the calibration of item and person parameters with the Rasch model and a good fit to the model. The second illustrated the use of multiple regression analysis to create norms for the psychological tests considering the variables age, education and gender as predictors of the BPR-5 scores. These three variables had significant effects explaining 8% (Abstract Reasoning), 13% (Verbal Reasoning), 12% (Spatial Reasoning), 8% (Numerical Reasoning) and 22% (Mechanical Reasoning) of the variance. (AU)

La Batería de Pruebas de Razonamiento (BPR-5) es un instrumento muy utilizado para la evaluación de la inteligencia en Brasil, disponiendo de tres formas: infantil (1° al 6° año de la Enseñanza Fundamental), Forma A (7° al 9° año de la Enseñanza Fundamental) y Forma B (Bachillerato y Educación Superior). Teniendo como finalidad la posibilidad de comparar los resultados entre sujetos que responden a diferentes versiones, el presente estudio tuvo como objetivo: (a) calibrar los ítems de las tres formas por el modelo de Rasch, realizando la igualación por ítems comunes a fin de obtener una escala equiparable para las tres formas, (b) actualizar las normas ampliando la representatividad de las muestras y produciendo normas para diferentes combinaciones de edad, escolarización y sexo, (c) describir patrones de desarrollo de la inteligencia a partir de la escala, común, producida entre los 6 y los 52 años. Dos estudios fueron reportados, el primer sobre la calibración de los parámetros de acuerdo con el modelo de Rasch, indicando un buen ajuste al modelo. El segundo estudio ejemplificó la utilización de regresión múltiple para crear normas para tests psicológicos, considerando las variables edad, educación y sexo como predictivos de los escores en el BPR-5. Esas tres variables tuvieron efectos significativos explicando 8% (Razonamiento Abstracto), 13% (Razonamiento Verbal), 12% (Razonamiento Espacial), 8% (Razonamiento Numérico), y 22% (Razonamiento Mecánico).(AU)

Leak and Scattering Assessment by Optically Stimulated Luminescence Dosimetry in a Helical Linear Accelerator / Valoración de Fuga y Dispersión por medio de Dosimetría de Luminiscencia Estimulada Ópticamente (OSL) en un Acelerador Lineal Helicoidal

Radiation absorbed doses to organs outside the radiation therapy treatment beam can be significant and therefore of clinical interest. Two sets of out-of-beam measurements were performed measuring the leak dose and the scattered dose, at 5 points within the accelerator components (accelerator tube and collimator) and at 21 points on the equipment and surroundings based on a positioning scheme. For this purpose, 52 Optically Stimulated Luminescence (OSL) dosimeters were used in a latest generation helical linear accelerator. Of the 200 cGy fired at a cheese-like phantom, 0.332% of the out-of-beam dose contribution was found to come from the leak and 0.784% was transformed into scattering. For these dose values, estimates of the risk of second tumors in long-term survivors indicate a reduced probability of acquiring a second secondary radiation malignancy, based on information from the 1990 BEIR Committee report.

La dosis absorbida de radiación a órganos fuera del haz de tratamiento de radioterapia puede ser significativa y, por lo tanto, de interés clínico. Se realizaron dos sets de mediciones fuera del haz para determinar la dosis de fuga y la dosis dispersa, en 5 puntos dentro de los componentes del acelerador (tubo de aceleración y colimador) y 21 puntos en el equipo y alrededores basado en un esquema de posicionamiento. Para este fin se utilizaron 52 dosímetros de luminiscencia estimulada ópticamente (OSL, Optically Stimulated Luminescence), en un acelerador lineal helicoidal de última generación. De los 200 cGy disparados a un maniquí tipo queso, se encontró que el 0.332% de la contribución de dosis fuera del haz provenía de la fuga y 0.784% se transforma en dispersión. Para estos valores de dosis, las estimaciones del riesgo de segundos tumores en los supervivientes a largo plazo indican una reducida probabilidad de contraer una segunda malignidad por radiación secundaria, según la información del informe del Comité BEIR de 1990.

La trazabilidad en las mediciones del laboratorio clínico: impacto en la calidad y seguridad del paciente / Traceability in clinical laboratory measurements: impact on quality and patient safety

Las mediciones confiables, trazables metrológicamente y comparables proporcionan la base racional para la evaluación de la calidad de un resultado y el fortalecimiento de las redes de laboratorios clínicos, lo cual permite mejorar la calidad de atención y la seguridad del paciente. En este documento se revisan los principios básicos que deben seguirse para garantizar la trazabilidad de las mediciones del laboratorio clínico, las ventajas de utilizar métodos trazables, el impacto de no hacerlo, y se discuten las principales limitaciones para relacionar las mediciones con los estándares de medición de referencia apropiados

Reliable, metrologically traceable, and comparable measurements provide the rationale for evaluating the quality of a result and strengthening clinical laboratory networks, thereby improving quality of care and patient safety. This document reviews the basic principles that must be followed to ensure the traceability of clinical laboratory results, the advantages of using traceable methods, the impact of not doing so, and the main limitations in relating measurements to appropriate reference standards

Precisão de réguas endodônticas milimetradas e orifício calibrador, e avaliação da regularidade da superfície do orifício calibrador / Accuracy of endodontic millimeter rulers and calibrator hole, and evaluation of the regularity of the calibrator hole surface

Objetivo: O objetivo desse artigo foi avaliar a precisão das porções milimetrada e calibradora das réguas endodônticas, e avaliar a regularidade da superfície dos orifícios calibradores. Métodos: A porção milimetrada das réguas Angelus, Maillefer, Maquira, Microdont e Prisma foi avaliada com paquímetro eletrônico digital. Os orifícios calibradores da Maillefer, Prisma e Angelus foram medidos com um projetor de perfil. A regularidade da superfície dos orifícios calibradores foi classificada em S1 ­ sem irregularidades ou S2 ­ com regularidades. A análise de precisão das porções milimetrada e calibradora foi realizada com o teste t (p=0,05); e as frequências dos tipos de superfície, com o teste do qui-quadrado (p<0,05). Resultados: A Maillefer foi a única régua endodôntica com precisão em todos os comprimentos e orifícios. A Prisma apresentou estatisticamente mais orifícios do tipo S2, quando comparada com outras réguas endodônticas avaliadas (p<0,05). Não houve diferença estatisticamente significativa entre Angelus e Maillefer (p>0,05). Conclusão: A Maillefer apresentou precisão nas porções milimetrada e calibradora. As réguas endodônticas da Angelus não foram precisas em nenhum comprimento da parte milimetrada e não foram precisas na maioria dos orifícios calibradores. A régua endodôntica Prisma mostrou significativamente mais orifícios calibradores com irregularidades na superfície do que Angelus e Maillefer. Destaca-se a necessidade de controle de qualidade e padrões específicos para fabricação das réguas endodônticas (AU).

Objective: The aim was to evaluate the accuracy of the millimeter and calibration portion and evaluate the regularity of the calibrator orifice surfaces of the endodontic rulers. Methods: The millimeter portion of the Angelus, Maillefer, Maquira, Microdont and Prisma rulers was evaluated with an electronic digital caliper. The calibration holes of the Maillefer, Prisma and Angelus were measured with Profile Projector. The surface regularity of calibration holes was evaluated and classified in S1- without irregularities and S2- with irregularities. The accuracy analysis of the millimeter and calibration was performed with T-Test (p=0.05) and the frequencies of the surface types with Chi-square (p<0.05). Results: The Maillefer was the only rulers with accuracy in all lengths and holes. Prisma presented statistically more S2 type holes when compared with other endodontic rulers evaluated (p <0.05). There was no statistically significant difference between Angelus and Maillefer (p> 0.05). Conclusion: The Maillefer presented accuracy in the millimeter and calibration portion. Angelus endodontic rulers were not accurate at any rated length of the millimeter portion and it was not accurate in most calibration holes evaluated. Prisma endodontic ruler showed significantly more calibration holes with irregular surfaces than Angelus and Maillefer. We emphasize the need for quality control and specific standards for endodontic rulers manufacturing (AU).

Characterization of Geiger-Müller radiation detectors response at the University of Costa Rica's Cyclotron Facilities / Caracterización de la respuesta de detectores de radiación Geiger-Müller en el Ciclotrón de la Universidad de Costa Rica

To ensure a reliable verification of a radiation detector, the right parameters for this response verification must be determined and a specific characterization on the detectors of interest must be performed. These were the main pillars of this study, where four Geiger-Müller at the University of Costa Rica's Cyclotron Facilities' main laboratories were studied and characterized using a 137Cs source. First, a verification of the inverse-square law was performed to corroborate the correct measurement by the detectors as the distance from a 137Cs source to the detectors was varied using a new design for a positioner support to ensure repeatability. This verification yielded a potential fit curve with and equation D=670635 x-1.961 (error percentage of 1.95%) and an R2 value of 0.9836. Then, using combinations of copper plates of widths 1.0 mm and 2.0 mm as attenuators between the source and the detectors, the mass attenuation coefficient for copper was obtained only as a reference value for future calibrations of the detectors. The result for this value was 0.040 cm2 /g. The results obtained in this study and the method developed to achieve these results will serve as a base for calibrations of the detectors at these facilities, which will ensure the safety of the patients and personnel in this building.

Para asegurar respuesta correcta de un detector de radiación, se deben determinar los parámetros correctos para esta verificación y debe realizarse una caracterización específica de los detectores de interés. Estos fueron los pilares principales de este estudio, donde se estudiaron y caracterizaron 4 detectores Geiger-Müller en los laboratorios principales del Ciclotrón de la Universidad de Costa Rica utilizando una fuente radiactiva de 137Cs. Primero, se realizó una verificación de la ley del inverso-cuadrado para corroborar la medición correcta de los detectores según se varía la distancia entre la fuente de 137Cs al detector utilizando un diseño nuevo de un soporte posicionador para la fuente que asegura la repetibilidad entre experimentos. Esta verificación resultó en una curva de ajuste potencial de ecuación D=670635x-1,961 (porcentaje de error de 1,95%) y un valor de R2 de 0,9836. Luego, utilizando combinaciones de placas de cobre de espesores 1,0 mm y 2,0 mm como atenuadores entre la fuente y los detectores, se obtuvo el coeficiente de atenuación másico para el cobre como un valor de referencia para futuras calibraciones de los detectores. Este resultado fue de 0,040 cm2/g. Los resultados obtenidos en esta investigación y el método desarrollado para lograr estos resultados servirán como una base para una futura confirmación metrológica calibraciones de los detectores en estos laboratorios, lo cual colaborará con la seguridad y protección radiológica de pacientes y trabajadores en este edificio.

Utilidad del índice UDT-65 en adultos con dolor torácico y electrocardiograma normal o no diagnóstico / Usefulness of the CPU-65 index in adults with chest pain and normal or non-diagnostic electrocardiogram

Resumen Objetivo: Evaluar la utilidad del índice UDT-65 para la estratificación del dolor torácico en urgencias en una población colombiana en la que se sospecha enfermedad coronaria. Método: Se condujo la validación externa del índice UDT-65 en una cohorte concurrente que incluyó pacientes que ingresaron a urgencias de una clínica cardiovascular en Bogotá con dolor torácico no traumático, y electrocardiograma normal o no diagnóstico. Se evaluaron 1320 pacientes de 18 o más años y se determinó la utilidad del índice en términos de calibración (uso de gráfico, ji al cuadrado para datos agrupados y prueba de bondad de ajuste de Hosmer-Lemeshow) y de capacidad de discriminación del modelo (curva de características operativas del receptor [ROC] y área bajo ella [AUC]). Resultados: El índice UDT-65 en esta población suministró evidencia de su utilidad en términos de calibración y capacidad de discriminación, para efectuar una buena aplicación de él en aquellos pacientes que consulten al servicio de urgencias de una clínica cardiovascular por dolor torácico no traumático de posible origen coronario. La capacidad de discriminación del índice UDT-65 fue adecuada, pues con un área bajo la curva ROC de 0.867 (IC 95% 0-847-0.885), que se acerca al valor obtenido (AUC 0.87) en la población española en que se desarrolló el índice. Conclusiones: Se necesitan más estudios similares en otras instituciones, dado el buen resultado, en beneficio de más pacientes.

Abstract Objective: To evaluate the clinical usefulness, in the emergency service, of the UDT-65 index for chest pain stratification in colombian population with suspected coronary disease. Method: The external validation of the UDT-65 index was conducted in a concurrent cohort that included patients admitted to the emergency service of the cardiovascular clinic in Bogotá with non-traumatic chest pain and normal or non-diagnostic electrocardiogram. 1320 patients were evaluated and the usefulness of this instrument was determined in terms of calibration (use of graph, Chi-square test for group data and the Hosmer-Lemeshow goodness-of-fit test) and discrimination capacity of the model (curve of receiver operating characteristics [ROC] and by finding the area under the curve [AUC]). Results: The UDT-65 index in the population under study, provided evidence of its usefulness in terms of calibration and discrimination capacity; this, in pursuance of a good application of the instrument in those patients who consult the Emergency Department of the cardiovascular clinic for non-traumatic chest pain of possible coronary origin. The discrimination capacity of the UDT65 index was adequate, with an area under the ROC curve of 0.867 (95 % CI 0.847-0.885), which is close in value to the one obtained (AUC 0.87) in the Spanish population where the original index was developed. Conclusions: More similar studies are needed in other institutions, due to the excellent and beneficial outcomes.

Controle de termômetros / Control de los termómetros / Control of thermometers

Esta Norma Técnica tem por objetivo estabelecer as orientações necessárias para aferição e leitura dos termômetros utilizados no controle de temperatura nos Bancos de Leite Humano e Postos de Coleta de Leite Humano, visando a garantia da qualidade nestes serviços e sua certificação.

Esta Norma Técnica tiene como objetivo establecer las orientaciones necesarias para la medición y la lectura de los termómetros utilizados en el control de la temperatura en los Bancos de Leche Humana y en los Centros de Recolección de Leche Humana, con el fin de garantizar la calidad de estos servicios y su certificación.

Application of 3d analysis technology of vision system image in sports medicine / Aplicação da tecnologia de análise 3d de imagens do sistema de visão na medicina esportiva / Aplicación de la tecnología de análisis 3d de la imagen del sistema de visión en medicina deportiva

ABSTRACT Background: Objective: The study of sports biomechanics in sports medicine usually requires a special image analysis system (software) to obtain 3D kinematics data. Taking the swimming project in sports medicine as an example, 3D water images in water have always been relatively complicated and difficult. As light travels in different media, it will refract and reflect. When testing underwater movements, if only a land camera or an underwater camera is used for testing, the error caused by light refraction will be larger, which will affect the accuracy of the test data even more. Methods: Taking breaststroke movement as an example, a three-dimensional measurement method based on the Kwon3D movement analysis system is introduced. This method is different from the simple underwater camera test. It is a three-dimensional test method combining a land camera and an underwater camera. Two underwater cameras and two land cameras were used to simultaneously calibrate the water and underwater space with the same calibration frame in the experiment after analyzing and verifying the accuracy of 3D reconstruction. Results: The comprehensive reconstruction error is small, and the average relative error is less than 1%. Conclusions: The application of three-dimensional image analysis technology of vision systems in sports medicine is reasonable and worth promoting. Level of evidence II; Therapeutic studies - investigation of treatment results.

RESUMO Antecedente: Objetivo: O estudo da biomecânica do esporte na medicina esportiva geralmente requer o uso de um sistema especial de análise de imagens (software) para a obtenção de dados cinemáticos 3D. Tomando o projeto de natação na medicina esportiva como exemplo, a análise de imagens 3D da água na água sempre foi um teste relativamente complicado e difícil. À medida que a luz viaja em diferentes meios, ela refratará e refletirá. Ao testar movimentos subaquáticos, se apenas uma câmera terrestre ou subaquática for usada para o teste, o erro causado pela refração da luz será maior, o que afetará a precisão dos dados de teste ainda mais. Métodos: Tomando o movimento de nado peito como exemplo, um método de medição tridimensional baseado no sistema de análise de movimento Kwon3D é introduzido. Este método é diferente do teste simples de câmera subaquática. É um método de teste tridimensional que combina uma câmera terrestre e uma câmera subaquática. No experimento, duas câmeras subaquáticas e duas câmeras terrestres foram usadas para calibrar simultaneamente a água e o espaço subaquático com o mesmo quadro de calibração. Depois de analisar e verificar a precisão da reconstrução 3D. Resultados: O erro de reconstrução abrangente é pequeno e o erro relativo médio é inferior a 1% Conclusões: A aplicação da tecnologia de análise de imagem tridimensional do sistema de visão na medicina esportiva é razoável e vale a pena promover. Nível de evidência II; Estudos terapêuticos- investigação dos resultados do tratamento.

RESUMEN Antecedente: Objetivo: El estudio de la biomecánica del deporte en la medicina deportiva generalmente requiere el uso de un sistema de análisis de imágenes especial (software) para obtener datos de cinemática 3D. Tomando como ejemplo el proyecto de natación en medicina deportiva, el análisis de imágenes de agua en 3D en el agua siempre ha sido una prueba relativamente complicada y difícil. A medida que la luz viaja en diferentes medios, se refractará y reflejará. Al probar los movimientos bajo el agua, si solo se utiliza una cámara terrestre o una cámara submarina para realizar la prueba, el error causado por la refracción de la luz será mayor, lo que afectará aún más la precisión de los datos de la prueba. Métodos: tomando como ejemplo el movimiento de la brazada, se introduce un método de medición tridimensional basado en el sistema de análisis de movimiento Kwon3D. Este método es diferente de la simple prueba de cámara subacuática. Es un método de prueba tridimensional que combina una cámara terrestre y una cámara submarina. En el experimento, se utilizaron dos cámaras submarinas y dos cámaras terrestres para calibrar simultáneamente el agua y el espacio submarino con el mismo marco de calibración. Después de analizar y verificar la precisión de la reconstrucción 3D. Resultados: el error de reconstrucción integral es pequeño y el error relativo promedio es inferior al 1%. Conclusiones: La aplicación de la tecnología de análisis de imágenes tridimensionales del sistema de visión en la medicina deportiva es razonable y vale la pena promoverla. Nivel de evidencia II; Estudios terapéuticos- investigación de los resultados del tratamiento.

Does successful urethral calibration rule out significant female urethral stenosis? confronting the confounder- an outcome analysis of successfully treated female urethral strictures

ABSTRACT Objective: The diagnosis and treatment of female urethral stricture disease (FUSD) are practiced variably due to the scarcity of data on evaluation, variable definitions, and lack of long-term surgical outcomes. FUSD is difficult to rule out solely on the basis of a successful calibration with 14F catheter. In this study, we have tried to characterize the variable clinical presentation of FUSD, the diagnostic utility of calibration, videourodynamic study(VUDS), and urethroscopy in planning surgical management. Materials and Methods: A retrospective review of records of 16 patients who underwent surgical management of FUSD was analyzed. The clinical history, examination findings, and the results of all the investigations (including uroflowmetry, VUDS findings, urethroscopy) they underwent, the procedures they had undergone, and the follow-up data were studied. Results: A total of 16 patients underwent surgical management of FUSD. 13 out of 16 patients had successful calibration with 14F catheter on the initial presentation. These 13 patients on VUDS demonstrated significant BOO and had variable stigmata of stricture on urethroscopy. The mean IPSS, flow rate, and PVR at presentation and after urethroplasty were 23.88±4.95, 7.72±4.25mL/s, 117.06±74.46mL and 3.50±3.44, 22.34±4.80mL/s, and 12.50±8.50mL, respectively. (p <0.05). The mean flow rate after endo dilation(17F) (n=12) was 11.4±2.5mL/s while after urethroplasty improved to 20.30±4.19mL/s and was statistically significant(p <0.05). Conclusions: An adept correlation between clinical assessment, urethroscopy findings, and VUDS is key in objectively identifying FUSD and planning surgical management. A good caliber of the urethra is not sufficient enough to rule out a significant obstruction due to FUSD. Early urethroplasty provides significantly better outcomes in patients who have failed dilation as a treatment.