Determination of Self-Heating in Silicon Photomultipliers.

The main consequence of radiation damage on a silicon photomultiplier (SiPM) is a significant increase in the dark current. If the SiPM is not adequately cooled, the power dissipation causes it to heat up, which alters its performance parameters. To investigate this heating effect, a measurement cycle was developed and performed with a KETEK SiPM glued to an Al2O3 substrate and with HPK SiPMs glued to either an Al2O3 substrate or a flexible PCB. The assemblies were connected either directly to a temperature-controlled chuck on a probe station, or through layers of materials with defined thermal resistance. An LED operated in DC mode was used to illuminate the SiPM and to tune the power dissipated in a measurement cycle. The SiPM current was used to determine the steady-state temperature reached by the SiPM via a calibration curve. The increase in SiPM temperature due to self-heating is analyzed as a function of the power dissipation in the SiPM and the thermal resistance. This information can be used to adjust the operating voltage of the SiPMs, taking into account the effects of self-heating. Similarly, this approach can be applied to investigate the unknown thermal contact of packaged SiPMs.

The Potential of Essential Oils from Active Packaging to Reduce Ethylene Biosynthesis in Plant Products. Part 1: Vegetables (Broccoli and Tomato).

Essential oils (EOs) extracted from plants have a high potential to reduce ethylene biosynthesis, although their effects have not been deeply studied yet on the key components of the ethylene biosynthesis pathway: l-aminocyclopropane-1-carboxylic (ACC) oxidase activity, ACC synthase activity, and ACC content. Hence, the present study aimed to elucidate the effects of released EOs from active packaging (with different EO doses ranging from 100 to 1000 mg m-2) on the ethylene biosynthesis key components of broccoli and tomato under different storage temperature scenarios. The largest ethylene inhibitory effects on broccoli and tomatoes were demonstrated by grapefruit EO and thyme essential EO (up to 63%), respectively, which were more pronounced at higher temperatures. Regarding EO doses, active packaging with a thyme EO dose of 1000 mg m-2 resulted in the strongest reduction (33-38%) of ethylene production in tomatoes. For broccoli, identical results were shown with a lower grapefruit EO dose of 500 mg m-2. The studied EO-active packaging decreased ACC synthase and ACC oxidase activities by 40-50% at 22 °C. Therefore, this EO-active packaging is a natural and effective technology to reduce ethylene biosynthesis in broccoli and tomatoes when they are stored, even in unsuitable scenarios at high temperatures.

Label-free electrochemical immunosensor for Ochratoxin a detection in coffee samples.

Ochratoxin A (OTA) is a nephrotoxic and carcinogenic mycotoxin frequently found in coffee, which directly impacts human health and the economy of many countries. For this reason, there has been a growing need for simple and sensitive tools for the on-site detection of this mycotoxin. In this study, we developed a label-free impedimetric immunosensor to detect OTA. The biosensor was built on a thin-film gold electrode evaporated on glass substrtes, modified with a self-assembled cysteamine monolayer and anti-OTA antibodies. Atomic force microscopy and Microspectroscopy RAMAN confirmed the successful functionalization of the electrodes. The biosensor performance was evaluated by electrochemical impedance spectroscopy and the measurements indicated a linear relationship between the change in the impedance values and the OTA concentration in the range from 0.5 to 100 ng mL-1 with a limit of detection of 0.15 ng mL-1. The biosensor was highly selective and did not suffer matrix interference when analyzed in coffee samples. Furthermore, considering the small sample volumes, the short time required for analysis, and the possibility of miniaturization, the developed biosensor represents a promising analytical device for on-site coffee quality analyses.

Microfluidic Paper-Based Blood Plasma Separation Device as a Potential Tool for Timely Detection of Protein Biomarkers.

A current challenge regarding microfluidic paper-based analytical devices (µPAD) for blood plasma separation (BPS) and electrochemical immunodetection of protein biomarkers is how to achieve a µPAD that yields enough plasma to retain the biomarker for affinity biosensing in a functionalized electrode system. This paper describes the development of a BPS µPAD to detect and quantify the S100B biomarker from peripheral whole blood. The device uses NaCl functionalized VF2 filter paper as a sample collection pad, an MF1 filter paper for plasma retention, and an optimized microfluidic channel geometry. An inverted light microscope, scanning electron microscope (SEM), and image processing software were used for visualizing BPS efficiency. A design of experiments (DOE) assessed the device's efficacy using an S100B ELISA Kit to measure clinically relevant S100B concentrations in plasma. The BPS device obtained 50 µL of plasma from 300 µL of whole blood after 3.5 min. The statistical correlation of S100B concentrations obtained using plasma from standard centrifugation and the BPS device was 0.98. The BPS device provides a simple manufacturing protocol, short fabrication time, and is capable of S100B detection using ELISA, making one step towards the integration of technologies aimed at low-cost POC testing of clinically relevant biomarkers.

TBISTAT: An open-source, wireless portable, electrochemical impedance spectroscopy capable potentiostat for the point-of-care detection of S100B in plasma samples.

Point-of-Care (POC) testing for biomarker detection demands techniques that are easy to use, readily available, low-cost, and with rapid response times. This paper describes the development of a fully open-source, modular, wireless, battery-powered, smartphone-controlled, low-cost potentiostat capable of conducting electrochemical impedance spectroscopy for the electrochemical detection of the S100B protein captured in an ANTI-S100B functionalized thin-film gold interdigitated electrode platform to support traumatic brain injury diagnosis and treatment. EIS results from the developed potentiostat were validated with a commercial benchtop potentiostat by comparing impedance magnitude and phase values along the EIS frequency range. In addition, an experimental design was performed for detecting S100B in spiked human plasma samples with S100B concentrations of clinical utility, and a calibration curve was found for quantifying S100B detection. No statistically significant differences were found between EIS results from the developed potentiostat and the commercial potentiostat. Statistically significant differences in the changes in charge transfer resistance signal between each tested S100B concentration (p < 0.05) were found, with a limit of detection of 35.73 pg/mL. The modularity of the proposed potentiostat allows easier component changes according to the application demands in power, frequency excitation ranges, wireless communication protocol, signal amplification and transduction, precision, and sampling frequency of ADC, among others, when compared to state-of-the-art open-source EIS potentiostats. In addition, the use of minimal, easy acquirable open-source hardware and software, high-level filtering, accurate ADC, Fast Fourier Transform with low spectral leakage, wireless communication, and the simple user interface provides a framework for facilitating EIS analysis and developing new affordable instrumentation for POC biosensors integrated systems.

The students' point of view on the teaching of anatomy at the Universidad del Norte, Colombia, amid the covid-19 pandemic / El punto de vista de los estudiantes sobre la enseñanza de anatomía en la Universidad del Norte, Colombia, en medio de la pandemia de covid-19

SUMMARY: The Covid-19 pandemic has disrupted long-standing educational practices. In Colombia, online learning depends on academic and non-academic factors, and this dependence makes e-learning even more difficult. This paper aimed to study the students' viewpoint of Anatomy teaching at Universidad del Norte, Colombia, during the Covid-19 pandemic. One hundred sixteen students answered a questionnaire about their opinions on several topics related to online learning of Anatomy. The strongest correlation observed showed that the students agree that online anatomy classes make the subject more difficult to learn when compared to face-to-face lectures. Negative attitudes toward motivation, lack of personal contact with classmates, and complaints about being taught without laboratory sessions with cadavers were among the principal negative attitudes in students. After almost one year, motivation to participate in online classes went down; however, students improved their judgment about remote anatomy learning and their views about using authentic anatomy images during online sessions and substituting real anatomy images for apps. Anatomy sessions will have to adapt their learning tools to e-learning as time constraints allow, creating a new environment for students to participate, learn, and take advantage of this change.

RESUMEN: La pandemia de Covid-19 ha interrumpido las prácticas educativas de larga data. En Colombia, el aprendizaje en línea depende de factores académicos y no académicos, y esta dependencia dificulta aún más el e-learning. Este trabajo tuvo como objetivo estudiar el punto de vista de los estudiantes sobre la enseñanza de Anatomía en la Universidad del Norte, Colombia, durante la pandemia Covid-19. Ciento dieciséis estudiantes respondieron un cuestionario sobre sus opiniones sobre varios temas relacionados con el aprendizaje en línea de Anatomía. La correlación más fuerte observada mostró que los estudiantes están de acuerdo en que las clases de anatomía en línea hacen que la asignatura sea más difícil de aprender en comparación con las clases presenciales. Las actitudes negativas hacia la motivación, la falta de contacto personal con los compañeros y las quejas de que se les enseñe sin sesiones de laboratorio con cadáveres fueron algunas de las principales actitudes negativas de los estudiantes. Después de casi un año, la motivación para participar en clases en línea disminuyó; sin embargo, los estudiantes mejoraron su juicio sobre el aprendizaje remoto de anatomía y sus puntos de vista sobre el uso de imágenes de anatomía auténticas durante las sesiones en línea y la sustitución de aplicaciones por imágenes de anatomía real. Las sesiones de anatomía deberán adaptar sus herramientas de aprendizaje al e-learning según lo permitan las limitaciones de tiempo, creando un nuevo entorno para que los estudiantes participen, aprendan y aprovechen este cambio.

Electrochemical Immunosensor for the Quantification of S100B at Clinically Relevant Levels Using a Cysteamine Modified Surface.

Neuronal damage secondary to traumatic brain injury (TBI) is a rapidly evolving condition, which requires therapeutic decisions based on the timely identification of clinical deterioration. Changes in S100B biomarker levels are associated with TBI severity and patient outcome. The S100B quantification is often difficult since standard immunoassays are time-consuming, costly, and require extensive expertise. A zero-length cross-linking approach on a cysteamine self-assembled monolayer (SAM) was performed to immobilize anti-S100B monoclonal antibodies onto both planar (AuEs) and interdigitated (AuIDEs) gold electrodes via carbonyl-bond. Surface characterization was performed by atomic force microscopy (AFM) and specular-reflectance FTIR for each functionalization step. Biosensor response was studied using the change in charge-transfer resistance (Rct) from electrochemical impedance spectroscopy (EIS) in potassium ferrocyanide, with [S100B] ranging 10-1000 pg/mL. A single-frequency analysis for capacitances was also performed in AuIDEs. Full factorial designs were applied to assess biosensor sensitivity, specificity, and limit-of-detection (LOD). Higher Rct values were found with increased S100B concentration in both platforms. LODs were 18 pg/mL(AuES) and 6 pg/mL(AuIDEs). AuIDEs provide a simpler manufacturing protocol, with reduced fabrication time and possibly costs, simpler electrochemical response analysis, and could be used for single-frequency analysis for monitoring capacitance changes related to S100B levels.

The delayed detection of an acute neurological worsening increases traumatic brain injury lethality / [La detección tardía del deterioro neurológico agudo incrementa la letalidad por trauma craneoencefálico.]

Introduction: Traumatic brain injury is a leading worldwide cause of death and disability in young people. Severity classification is based on the Glasgow Coma Scale. However, the neurological worsening in an acute setting does not always correspond to the initial severity suggesting an underestimation of the real magnitude of the injury. Objective: To study the correlation between the initial severity according to the Glasgow Coma Scale and the patient outcome in the context of different clinical and tomography variables. Materials and methods: We analyzed a retrospective cohort of 490 patients with closed traumatic brain injury requiring a stay in the intensive care unit of two third-level hospitals in Barranquilla. The risk was estimated by calculating the OR (95% CI). The significance level was established at an alpha value of 0.05. Results: Forty-one percent of all patients required orotracheal intubation; 51.2% were initially classified with moderate trauma and 6,0% as mild. The delay in the aggressive management of the traumas affected mainly those patients with traumas classified as moderate in whom lethality increased to 100% when there was delay in the detection of the neurological worsening and in the establishment of the aggressive treatment beyond 4 to 8 hours while the lethality in patients who received this treatment within the first hour reduced to <20%. Conclusions: The risk of lethality in traumatic brain injury increases with the delayed detection of neurological worsening in an acute setting, especially when aggressive management is performed after the first hour post-trauma.

Introducción. El trauma craneoencefálico es una de las principales causas de muerte y discapacidad en adultos jóvenes. Su gravedad se define según la escala de coma de Glasgow. Sin embargo, el deterioro neurológico agudo no siempre concuerda con la gravedad inicial indicada por la escala, lo que implica una subestimación de la magnitud real de la lesión. Objetivo. Estudiar la correlación entre la gravedad inicial del trauma craneoencefálico según la escala de coma de Glasgow y la condición final del paciente, en el contexto de diferentes variables clínicas y de los hallazgos de la tomografía. Materiales y métodos. Se analizó una cohorte retrospectiva de 490 pacientes con trauma craneoencefálico cerrado que requirieron atención en la unidad de cuidados intensivos de dos centros de tercer nivel de Barranquilla. La estimación del riesgo se estableció con la razón de momios (odds ratio, OR) y un intervalo de confianza (IC) del 95 %. Se utilizó un alfa de 0,05 como nivel de significación. Resultados. El 41,0 % de los pacientes requirió intubación endotraqueal; el 51,2 % había presentado traumas inicialmente clasificados como moderados y, el 6,0 %, como leves. El retraso en la implementación de un tratamiento agresivo afectó principalmente a aquellos con trauma craneoencefálico moderado, en quienes la letalidad aumentó al 100 % cuando no se detectó a tiempo el deterioro neurológico y, por lo tanto, el tratamiento agresivo se demoró más de 4 a 8 horas. Por el contrario, la letalidad fue de menos de 20 % cuando se brindó el tratamiento agresivo en el curso de la primera hora después del trauma. Conclusiones. El riesgo de letalidad del trauma craneoencefálico aumentó cuando el deterioro neurológico se detectó tardíamente y el tratamiento agresivo se inició después de transcurrida la primera hora a partir del trauma.

La detección tardía del deterioro neurológico agudo incrementa la letalidad por trauma craneoencefálico / The delayed detection of an acute neurological worsening increases traumatic brain injury lethality

Introducción. El trauma craneoencefálico es una de las principales causas de muerte y discapacidad en adultos jóvenes. Su gravedad se define según la escala de coma de Glasgow. Sin embargo, el deterioro neurológico agudo no siempre concuerda con la gravedad inicial indicada por la escala, lo que implica una subestimación de la magnitud real de la lesión. Objetivo. Estudiar la correlación entre la gravedad inicial del trauma craneoencefálico según la escala de coma de Glasgow y la condición final del paciente, en el contexto de diferentes variables clínicas y de los hallazgos de la tomografía. Materiales y métodos. Se analizó una cohorte retrospectiva de 490 pacientes con trauma craneoencefálico cerrado que requirieron atención en la unidad de cuidados intensivos de dos centros de tercer nivel de Barranquilla. La estimación del riesgo se estableció con la razón de momios (odds ratio, OR) y un intervalo de confianza (IC) del 95 %. Se utilizó un alfa de 0,05 como nivel de significación. Resultados. El 41,0 % de los pacientes requirió intubación endotraqueal; el 51,2 % había presentado traumas inicialmente clasificados como moderados y, el 6,0 %, como leves. El retraso en la implementación de un tratamiento agresivo afectó principalmente a aquellos con trauma craneoencefálico moderado, en quienes la letalidad aumentó al 100 % cuando no se detectó a tiempo el deterioro neurológico y, por lo tanto, el tratamiento agresivo se demoró más de 4 a 8 horas. Por el contrario, la letalidad fue de menos de 20 % cuando se brindó el tratamiento agresivo en el curso de la primera hora después del trauma. Conclusiones. El riesgo de letalidad del trauma craneoencefálico aumentó cuando el deterioro neurológico se detectó tardíamente y el tratamiento agresivo se inició después de transcurrida la primera hora a partir del trauma.

Introduction: Traumatic brain injury is a leading worldwide cause of death and disability in young people. Severity classification is based on the Glasgow Coma Scale. However, the neurological worsening in an acute setting does not always correspond to the initial severity suggesting an underestimation of the real magnitude of the injury. Objective: To study the correlation between the initial severity according to the Glasgow Coma Scale and the patient outcome in the context of different clinical and tomography variables. Materials and methods: We analyzed a retrospective cohort of 490 patients with closed traumatic brain injury requiring a stay in the intensive care unit of two third-level hospitals in Barranquilla. The risk was estimated by calculating the OR (95% CI). The significance level was established at an alpha value of 0.05. Results: Forty-one percent of all patients required orotracheal intubation; 51.2% were initially classified with moderate trauma and 6,0% as mild. The delay in the aggressive management of the traumas affected mainly those patients with traumas classified as moderate in whom lethality increased to 100% when there was delay in the detection of the neurological worsening and in the establishment of the aggressive treatment beyond 4 to 8 hours while the lethality in patients who received this treatment within the first hour reduced to <20%. Conclusions: The risk of lethality in traumatic brain injury increases with the delayed detection of neurological worsening in an acute setting, especially when aggressive management is performed after the first hour post-trauma.

Novel Data Mining Methodology for Healthcare Applied to a New Model to Diagnose Metabolic Syndrome without a Blood Test.

Metabolic Syndrome (MetS) is a cluster of risk factors that increase the likelihood of heart disease and diabetes mellitus. It is crucial to get diagnosed with time to take preventive measures, especially for patients in locations without proper access to laboratories and medical consultations. This work presented a new methodology to diagnose diseases using data mining that documents all the phases thoroughly for further improvement of the resulting models. We used the methodology to create a new model to diagnose the syndrome without using biochemical variables. We compared similar classification models, using their reported variables and previously obtained data from a study in Colombia. We built a new model and compared it to previous models using the holdout, and random subsampling validation methods to get performance evaluation indicators between the models. Our resulting ANN model used three hidden layers and only Hip Circumference, dichotomous Waist Circumference, and dichotomous blood pressure variables. It gave an Area Under Curve (AUC) of 87.75% by the IDF and 85.12% by HMS MetS diagnosis criteria, higher than previous models. Thanks to our new methodology, diagnosis models can be thoroughly documented for appropriate future comparisons, thus benefiting the diagnosis of the studied diseases.

Riesgo de depresión en pacientes con Diabetes mellitus tipo 2 según tiempo de evolución: Centro Diabetológico Aragua, Venezuela. 2011 / Depression risk patients with type 2 Diabetes (DM2) by year of development: Center Aragua Diabetologist 2011

In this study had as objective to describe the risk of depression in patients with type 2 diabetes mellitus, according to years of evolution Diabetologico Center in Maracay, Aragua State. It was a cross sectional study with 45 patients, in whom was evaluated risk of depression with test "Yesavage" in its shortened version. Demographic variables were recorded and antiquity of diagnosis (0 to 5.6 to 9 and >10 years). The results reported average age 60 years; 57% female, 43% male; married 47 %, occupation in the Home 55 %; 54% schooling which primary studies were carried out and the risk of depression was in >10 years of evolution, was presented in the 80% depression established and with a 20% risk for depression, the degree of primary education is a key factor in living conditions that favors the risks and chronic complications of diabetes. Finally the patients with DM2 with more than 10 years of evolution, with female-dominated occupation of the home and with an average age of 67 years, are important determinants of quality of life. It is recommended the development of educational programs that enable them to generate changes in the style of life and decrease risk factors.

En este estudio se planteó como objetivo describir el riesgo de depresión en pacientes con diabetes Mellitus tipo 2, según años de evolución en Centro Diabetológico Maracay, Estado Aragua. Fue realizado un estudio transversal con 45 pacientes, en los cuales se evaluó riesgo de depresión con test "Yesavage" en su versión reducida. Se registraron variables sociodemográficas y antigüedad del diagnóstico (0 a 5,6 a 9 y >10 años). Los resultados reportaron edad promedio 60 años; 57% femenino, 43% masculino; casados 47%, ocupación en el Hogar 55%; Escolaridad 54% los cuales realizaron estudios primarios y el Riesgo de depresión fue en >10 años de evolución, se presentó en el 80% depresión establecida y un 20% con riesgo para depresión, El grado de instrucción primaria es un factor determinante de condiciones de vida que favorece los riesgos y complicaciones crónicas de la diabetes. Finalmente los pacientes con DM2 con más de 10 años de evolución, a predominio femenino con ocupación del Hogar y con edad promedio de 67 años, constituyen factores determinantes de calidad de vida. Se recomienda el desarrollo de programas educativos que permitan generar cambios del estilo de vida y la disminución de factores de riesgos.

Yucca (Manihot esculenta Crantz) starch polysaccharide dextrination through biological procedures

El proceso de dextrinación del almidón de la yuca (Manihot esculenta) utilizando Aspergillus niger fue evaluado a fin de obtener azúcares fermentables a partir del polisacárido original. La concentración máxima de glucosa (2466mg·l-1) se obtuvo a 30ºC en un período de tres días. El análisis estadístico (P=0,05) de los resultados experimentales reveló un comportamiento de segundo orden para el proceso. La interacción entre las variables tiempo y temperatura afectaron significativamente la producción de glucosa debida a la acción enzimática de A. niger sobre el sustrato. El análisis de la superficie de respuesta mostró un punto óptimo para el proceso en 37ºC y 2,75 días, y una interacción significativa entre tiempo y temperatura. Se concluye que la acción catalítica de A. niger depende fuertemente de las condiciones ambientales en las que se desarrolla el proceso.