DISEÑO Y CONSTRUCCIÓN DE UN SISTEMA DE ELECTRÓLISIS PARA SÍNTESIS DE NANOPARTÍCULAS DE PLATA UTILIZANDO INSTRUMENTACIÓN VIRTUAL CON LABVIEW (DESIGN AND CONSTRUCTION OF AN ELECTROLISIS SYSTEM FOR SILVER NANOPARTICLES SYNTHESIS BY VIRTUAL INSTRUMENTATION)

ResumenActualmente, la nanotecnología está presente en muchos productos que se encuentran en el mercado y cada vez tiene mayor uso en la solución de problemáticas, al ser un área interdisciplinaria, es necesario el trabajo en conjunto de científicos e ingenieros para el desarrollo de tecnologías. Los materiales en una escala nanométrica requieren de sistemas especializados y complejos, dando como resultado variedad de estructuras tales como nanovarillas, nanoalambres, nanocolumnas y nanopartículas, por mencionar algunas. En este trabajo, se presenta un sistema de síntesis de nanopartículas de plata utilizando un multímetro Fluke de doble pantalla (dual display) para medición de corriente, una fuente de voltaje de la marca BK Precision, una tarjeta Arduino como interface e instrumentación virtual con LabVIEW para control de los tiempos de reacción y el tiempo de conmutación de polaridad de los electrodos. En conjunto es un sistema que puede realizar las tareas de adquisición, procesamiento y presentación de datos. Se realizaron dos experimentos de síntesis de NPs, con un tiempo de proceso de 30 minutos, tiempo de conmutación de la polaridad de 5 minutos a 60 °C variando el voltaje aplicado de 5 y 10 V. La obtención de las NPs en los experimentos es demostrada analizando los espectros de absorción UV-Vis de la solución coloidal obtenida. Se obtuvieron NPs con un tamaño promedio de 122 nm para el voltaje de aplicación de 5 V y 106 nm para las NPs sintetizadas con un voltaje de 10 V. La distribución de tamaño fue obtenida utilizando la técnica de Dispersión de Luz Dinámica (DLS, Dynamic Light Scattering). En futuras investigaciones se pretende utilizar las NPs obtenidas con este sistema automático para realizar la síntesis de óxido de zinc dopado con plata (ZnO tipo p), el cual, será utilizado para la fabricación de dispositivos electrónicos como LEDs y celdas solares.Palabras Claves: Nanopartículas, Plata, Electrolisis, Automatizado.                                       AbstractCurrently, nanotechnology is present in many products that are in the market and is increasingly used to solve problems, being an interdisciplinary area, it is necessary the joint work of scientists and engineers for the development of technologies. Materials on a nanometric scale require specialized and complex systems, resulting in a variety of structures such as nanowires, nanowires, nanocolumns and nanoparticles, to name a few. In this work, a system for the synthesis of silver nanoparticles is presented using a dual display Fluke multimeter (dual display) for current measurement, a voltage source of the BK Precision brand, an Arduino card as an interface and virtual instrumentation with LabVIEW for control of reaction times and electrode polarity switching time. Together it is a system that can perform the tasks of acquisition, processing and presentation of data. Two experiments of synthesis of NPs were carried out, with a process time of 30 minutes, polarity switching time of 5 minutes at 60 ° C varying the applied voltage of 5 and 10 V. The formation of NPs in the experiments is demonstrated by analyzing the UV-Vis absorption spectra of the colloidal solution obtained. NPs with an average size of 122 nm were obtained for the application voltage of 5 V and 106 nm for NPs synthesized with a voltage of 10 V. The size distribution was obtained using Dynamic Light scattering. In future research it is intended to use the NPs obtained with this automatic system to perform the synthesis of zinc oxide doped with silver (ZnO type p), which will be used for the manufacture of electronic devices such as LEDs and solar cells.Keywords: Nanoparticles, Silver, Electrolysis, Automated

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care

Risk of COVID-19 after natural infection or vaccinationResearch in context

Summary: Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health

Risk of COVID-19 after natural infection or vaccinationResearch in context

Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health