Abstract:The accuracy of BIA measurements is limited by different sources of error such as physical model, cross sectional area, ethnicity, body hydration, age and level of body fat among other variables. Equation for each population is required as they can produce overestimation when manufacturer's equations are used. The classical measurements hand to foot has shown better correlation against hydrodensitometry than foot to foot or hand to hand. However there is a lack for an accepted standard of BIA procedures. This is compounded when there is not a good report of the BIA study's methodology; hence the comparability between the results is poor and reduces the reliability of the method. Perhaps, standardization of methods would be the first step for BIA studies to move forward and subsequently improve its accuracy. Standardized procedures could also minimize the impact of these variables on studies results. The aim of this study was to propose a protocol as a checklist to standardize BIA procedures and produce comparable results from future studies performed with the classic hand-foot configuration in adults.

La espectroscopia de impedancia eléctrica (EIE) es una técnica que permite analizar las propiedades eléctricas de materiales, incluso biológicos, al inducir señales eléctricas alternas a diferentes frecuencias y medir las señales de respuesta. Se ha utilizado para determinar la madurez en frutos, identificar adulteraciones en productos cárnicos y lácteos, determinar propiedades físico-químicas en todo tipo de matrices alimentarias e incluso para cuantificar microorganismos presentes en alimentos y en superficies de trabajo. Esta técnica es segura, no invasiva, rápida, portátil, de bajo costo y fácil de usar; lo que la convierte en un método con un gran potencial ser usado en la industria de alimentos para monitorear y controlar los procesos de calidad. La presente revisión sistemática recopila información científica publicada entre el año 2012 y 2018 que describe el uso EIE aplicada al control de calidad de alimentos. Se realizó una búsqueda en las bases de datos ScienceDirect, Springer y también en el buscador Google académico mediante la estrategia: Spectroscopy electrical impedance AND Foods. Aplicando una serie de filtros y una búsqueda manual se encontraron 53 artículos y una tesis relacionados con la temática. Se encontró que la mayoría de los estudios se centran en la evaluación de calidad de productos cárnicos y pesqueros, así como en la caracterización de los cambios generados durante los procesos térmicos y maduración de frutas.

Inside clinical research, gait analysis is a fundamental part of the functional evaluation of the human body's movement. Its evaluation has been carried out through different methods and tools, which allow early diagnosis of diseases, and monitoring and assessing the effectiveness of therapeutic plans applied to patients for rehabilitation. The observational method is one of the most used in specialized centers in Colombia; however, to avoid any possible errors associated with the subjectivity observation, technological tools that provide quantitative data can support this method. This paper deals with the methodological process for developing a computational tool and hardware device for the analysis of gait, specifically on articular kinematics of the knee. This work develops a prototype based on the fusion of inertial measurement units (IMU) data as an alternative for the attenuation of errors associated with each of these technologies. A videogrammetry technique measured the same human gait patterns to validate the proposed system, in terms of accuracy and repeatability of the recorded data. Results showed that the developed prototype successfully captured the kneejoint angles of the flexion-extension motions with high consistency and accuracy in with the measurements obtained from the videogrammetry technique. Statistical analysis (ICC and RMSE) exhibited a high correlation between the two systems for the measures of the joint angles. These results suggest the possibility of using an IMU-based prototype in realistic scenarios for accurately tracking a patient's knee-joint kinematics during a human gait.

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Bioelectrical impedance analysis (BIA) is a noninvasive method for assessment of body composition with better accuracy, and less inter-observer error than anthropometry. Despite these advantages, reported BIA equations may not be suitable for populations other than where they were developed. The aim of this study was to develop equations for single-frequency (SF) BIA and bioelectrical impedance spectroscopy (BIS) using a three compartment (3C) model as the criterion method to predict total body water (TBW) and fat-free mass (FFM) in South-American adult women. A cross-sectional observational study was conducted using a convenience sample (n=40). SF-BIA and BIS prediction equations were developed using forward-stepwise multiple regression with TBW by D2O and FFM by 3C model as dependent variables; and weight, resistance and impedance index (stature2/resistance) as independent variables. A cross-validation was conducted in a randomly split subsample (n=20). Four final equations were developed. There were no differences between SF-BIA and BIS equations for TBW (p=0.68) and FFM (p=0.66). The cross-validation showed a strong association and broadly meets the limits of agreement with the 3C reference method. The equations have an excellent goodness-of-fit to predict TBW and FFM. Validation of these equations in populations of different ages and ethnicities is warranted.