Características bacteriológicas, físicas y pH del agua de consumo humano del municipio de Une-Cundinamarca / Bacteriological and physical characteristics and pH of water for human consumption in the municipality of Une-Cundinamarca

Resumen Objetivo. Determinar características bacteriológicas, físicas y pH del agua para consumo humano que abastece al municipio de Une, Cundinamarca-Colombia. Métodos. Se tomaron 13 muestras de agua: 10 de la zona rural y 3 de la zona urbana. Del total de muestras tomadas en la zona rural, 7 no tenían ningún tratamiento, mientras que 3 tenían algún tipo de tratamiento. Las 3 muestras tomadas en la cabecera municipal, todas tenían tratamiento. Se utilizó la técnica de filtración por membrana para los análisis bacteriológicos, y los métodos nefelométrico, turbidimétrico y potenciométrico, para los análisis físicos y el pH. Resultados. Se obtuvo como resultado pH inferior a 6; 12 puntos superan el valor máximo de turbiedad y 5 puntos para la determinación de color. Se observó la presencia de Coliformes totales, E. coli y Enterococcus en las muestras analizadas, en cantidad que sobrepasa lo establecido en la normativa colombiana.

Abstract Objective. To determine bacteriological and physical characteristics and pH of water for human consumption that supplies the municipality of Une, Cundinamarca-Colombia. Methods. Thirteen water samples were taken: 10 from the rural area and 3 from the urban area. Of the total number of samples taken in the rural area, 7 had no treatment at all, while 3 had some type of treatment. The 3 samples taken in the municipal capital, all had treatment. The membrane filtration technique was used for bacteriological analysis and the nephelometric, turbidimetric and potentiometric methods for physical analysis and pH. Results. The result was pH lower than 6; 12 points exceed the maximum value turbidity and 5 points for the determination of color. The presence of total Coliforms, E. coli and Enterococcus was observed in the analyzed samples, in an amount that surpasses the established in the Colombian regulations.

Use of Transient Time Response as a Measure to Characterize Phononic Crystal Sensors.

Phononic crystals are periodic composite structures with specific resonant features that are gaining popularity in the field as liquid sensors. The introduction of a structural defect in an otherwise periodic regular arrangement can generate a resonant mode, also called defect mode, inside the characteristic band gaps of phononic crystals. The morphology, as well as the frequency in which these defect modes appear, can give useful information on the composition and properties of an analyte. Currently, only gain and frequency measurements are performed using phononic crystal sensors. Other measurements like the transient response have been implemented in resonant sensors such as quartz microbalances showing great results and proving to be a great complimentary measure to the gain and frequency measurements. In the present paper, a study of the feasibility of using the transient response as a measure to acquire additional information about the analyte is presented. Theoretical studies using the transmission line model were realized to show the impact of variations in the concentration of an analyte, in this case, lithium carbonate solutions, in the transient time of the system. Experimental realizations were also performed showing that the proposed measurement scheme presents significant changes in the resulting data, indicating the potential use of this measure in phononic crystal sensors. This proposed measure could be implemented as a stand-alone measure or as a compliment to current sensing modalities.

Physiological coherence in healthy volunteers during laboratory-induced stress and controlled breathing.

Physiological coherence has been related with a general sense of well-being and improvements in health and physical, social, and cognitive performance. The aim of this study was to evaluate the relationship between acute stress, controlled breathing, and physiological coherence, and the degree of body systems synchronization during a coherence-generation exercise. Thirty-four university employees were evaluated during a 20-min test consisting of four stages of 5-min duration each, during which basal measurements were obtained (Stage 1), acute stress was induced using validated mental stressors (Stroop test and mental arithmetic task, during Stage 2 and 3, respectively), and coherence states were generated using a controlled breathing technique (Stage 4). Physiological coherence and cardiorespiratory synchronization were assessed during each stage from heart rate variability, pulse transit time, and respiration. Coherence measurements derived from the three analyzed variables increased during controlled respiration. Moreover, signals synchronized during the controlled breathing stage, implying a cardiorespiratory synchronization was achieved by most participants. Hence, physiological coherence and cardiopulmonary synchronization, which could lead to improvements in health and better life quality, can be achieved using slow, controlled breathing exercises. Meanwhile, coherence measured during basal state and stressful situations did not show relevant differences using heart rate variability and pulse transit time. More studies are needed to evaluate the ability of coherence ratio to reflect acute stress.

Differential Phononic Crystal Sensor: Towards a Temperature Compensation Mechanism for Field Applications Development.

Phononic crystals are resonant structures with great potential to be implemented in applications as liquid sensors. The use of the symmetry reduction technique allows introducing relevant transmission features inside bandgaps by creating defect modes in a periodic regular structure. These features can be used as measures to quantify changes in the speed of sound of liquid samples that could be related to the concentration of analytes or the presence of pathogens among other interesting applications. In order to be able to implement this new technology in more challenging applications, such as biomedical applications, it is necessary to have a very precise and accurate measurement. Changes in temperature greatly affect the speed of sound of the liquid samples, causing errors in the measurements. This article presents a phononic crystal sensor that, by introducing additional defect modes, can carry out differential measurements as a temperature compensation mechanism. Theoretical studies using the transmission line model and analytes at various temperatures show that the proposed temperature compensation mechanism enhances the performance of the sensor in a significant way. This temperature compensation strategy could also be implemented in crystals with different topologies.

PURIFICACIÓN DEL ANTÍGENO 38 kDa DE Mycobacterium tuberculosis Y SU POTENCIAL USO EN DIAGNÓSTICO MEDIANTE INMUNOSENSORES PIEZOELÉCTRICOS / Mycobacterium tuberculosis 38 kDa Antigen Purification and Potential Diagnostic Use by Piezoelectric Immunosensors

Un paso crucial en el desarrollo de un inmunosensor piezoeléctrico para la detección de tuberculosis (TB), es la selección y obtención de los inmunoreactivos empleados en el inmunoensayo y la estrategia para la biofuncionalización del transductor. Diversos estudios han reportado el uso del antígeno proteico 38kDa (Ag38kDa) de Mycobacterium tuberculosis (Mtb) como un buen biomarcador de la enfermedad y el cumplimiento de las características físicas y bioquímicas para ser inmovilizado por monocapas autoensambladas (SAMs), en la superficie del electrodo de oro de cristales piezoeléctricos. Un inmunosensor piezoeléctrico desarrollado a partir de un antígeno nativo purificado de Mtb podría ser un método alternativo simple para la detección de Mtb con ventajas de rapidez y reusabilidad, contribuyendo al control y el tratamiento oportuno de la enfermedad. En este estudio se presenta el proceso de purificación del Ag38kDa a partir de proteínas de secreción filtradas de cultivo (CFP) de Mtb para ser usado como inmunoreactivo con potencial aplicación en la detección de Mtb con inmunosensores piezoeléctricos. Se obtuvieron cristales funcionalizados mediante la técnica modificada de monocapas autoensambladas (SAMs), con el antígeno nativo purificado y CFP. Las superficies biofuncionalizadas fueron caracterizadas cualitativamente con microscopía de fuerza atómica (AFM) para validar las condiciones de optimización del protocolo de inmovilización con antígenos de secreción de Mtb. Estos cristales modificados pueden ser acoplados a un sistema de caracterización de un inmunosensor piezoeléctrico para la detección de Mtb mediante un inmunoensayo competitivo directo.

The selection and procurance of the immunoreagents used in the immunoassay and biofunctionalisation transducer strategy, are a key in the piezoelectric immunosensor development for the detection of tuberculosis (TB). Many have reported the use of 38kDa protein antigen (Ag38kDa) from Mycobacterium tuberculosis (Mtb) such as good biomarker of TB disease and compliance with physical and biochemical characteristics to be immobilized by self-assembled monolayers (SAMs), in the gold electrode of piezoelectrics crystals surfaces. A piezoelectric immunosensor developed from purified native antigens of Mtb may be an alternative simple method for detection of Mtb with speed and reusable advantages, contributing to the control and early treatment of disease. In this paper, the purification process of Ag38kDa Mtb from secretory proteins filtered culture (CFP) from Mtb is presented as an immunoreactive with potential application in the detection of Mtb by piezoelectric immunosensors. Functionalized crystals were obtained by using the modified self-assembled monolayers (SAMs) technique, with purified native antigen and CFP. The functionalized surfaces were qualitatively characterized using atomic force microscopy (AFM) in order to validate the immobilization protocol optimal conditions for secretion antigens from Mtb. These modified crystals may be coupled to piezoelectric immunosensor characterization system for detecting of Mtb by a direct competition immunoassay.

Development of an apnea detector for neonates using diaphragmatic surface electromyography.

Respiratory diseases are among the most important and serious conditions that can affect the newborn baby. A cessation of breathing, longer than 15 seconds, or accompanied by hypoxia or bradycardia, is called apnea of prematurity (AOP) and has been found in more than 50% of premature infants. An apnea detector used in infant monitoring has been designed and constructed and is intended to be applied in a clinical environment. Diaphragmatic surface EMG has been used as the technique for detecting apnea episodes due to a direct relation with the respiratory drive. Both obstructive and central apnea can be determined as well as heart rate. Good performance and feasibility have been shown by the prototype.

P300-based brain computer interface experimental setup.

A Brain-Computer interface (BCI) is a communication system that enables the generation of a control signal from brain signals such as sensorymotor rhythms and evoked potentials; therefore, it constitutes a novel communication option for people with severe motor disabilities (such as Amyotrophic Lateral Sclerosis patients). This paper presents the development of a P300-based BCI. This prototype uses a homemade six-channel electroencephalograph for the acquisition of the signals, and a visual stimulation matrix; since this matrix contains letters of the alphabet as well as images associated to them, it permits word-writing and the elaboration of messages with the images. To process the signals the software BCI2000 and MATLAB 7.0 were used. The latter was used to program three linear translation algorithms (Stepwise Linear Discriminant Analysis, Lineal Discriminant Analysis and Least Squares) to convert the brain signals into communication signals. These algorithms had a classification accuracy of 90.73 %, 95.75 % and 89.45 % respectively, when using raw data; and of 90.78%, 49.48 % and 53.9 %, when data was previously common-average filtered. The experimental setup was tested in ten healthy volunteers; 5 of them got a 100% success, 1 a 90% success, 2 an around 70% success and 2 a 50% success, in the online free-spelling tests.