RF performance projections of graphene FETs vs. silicon MOSFETs

A graphene field-effect-transistor (GFET) model calibrated with extracted device parameters and a commercial 65 nm silicon MOSFET model are compared with respect to their radio frequency behavior. GFETs slightly lag behind CMOS in terms of speed despite their higher mobility. This is counterintuitive, but can be explained by the effect of a strongly nonlinear voltage-dependent gate capacitance. GFETs achieve their maximum performance only for narrow ranges of VDS and IDS, which must be carefully considered for circuit design. For our parameter set, GFETs require at least μ = 3000 cm2 V−1 s−1 to achieve the same performance as 65 nm silicon MOSFETs.Peer ReviewedPreprin

Impulse oscillometry reference values and bronchodilator response in three- to five-year old children living at high altitude

Q2Q1Introduction: Impulse oscillometry (IOS) is used to measure airway impedance. It is an effective tool for diagnosing and treating respiratory diseases, and it has the advantage that it does not require forced respiratory maneuvers. IOS reference values are required for each population group. Objective: This study aimed to determine the IOS reference values and bronchodilator response in healthy preschool children living in Bogotá, Colombia. Methods: We performed a cross-sectional study in preschool children who had no history of respiratory disease; 96 children fit the parameters for testing to determine normal values according to the American Thoracic Society and European Respiratory Society criteria. Results: Values for respiratory resistance (Rrs) and reactance (Xrs) at 5, 10, and 20 Hz, respiratory impedance (Zrs, and resonance frequency (Fres) were established. Height was the most influential independent variable for IOS values; an increase in height led to a reduction in Rrs5 and Rrs20 and an increase in Xrs5. After the administration of 400 mcg of salbutamol the values for Rrs5(-17.48%), Rrs20(-8.63%), Fres (-10.68%), and area of reactance (-35.44%) were reduced, meanwhile Xrs5 (15.35%) was increased. Conclusions: Normal IOS values before and after the administration of 400 mcg of salbutamol were determined for a population of children aged 3-5 years at 2,640 m. Reference IOS equations for these children are presented. A relative change of up to -28% and 36% after the use of salbutamol for respiratory resistance and reactance, respectively, should be considered as an upper limit of the normal range, and possible appropriate cut-off values for defining significant response for evaluating therapeutic interventions. Keywords: children; cross-sectional studies; high altitude; oscillometry; reference values; respiratory function tests.N/

Respiratory failure and death in vulnerable premature children with lower respiratory tract illness

Background. Efforts to better understand the risk factors associated with respiratory failure (RF) and fatal lower respiratory tract infection (LRTI) in premature children in developing countries are necessary to elaborate evidenced-based preventive interventions. We aim to characterize the burden of respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) LRTI in premature children and determine risk factors for RF and fatal illness in a vulnerable population. Methods. This is a prospective, population-based, cross-sectional study. Subjects with severe LRTI were enrolled during respiratory season. Risk factors for RF and death in premature infants were investigated. Results. A total of 664 premature children participated. Infant's hospitalization rate due to LRTI was 82.6/1000 (95% confidence interval [CI], 68.6-96.7/1000). Infant's RSV and hMPV rates were 40.9/1000 (95% CI, 36.3-45.6/1000) and 6.6/1000 (95% CI, 3.9- 9.2/1000), respectively. The RF rate was 8.2/1000 (95% CI, 4.9-11.5/1000). The LRTI mortality was 2.2/1000 (95% CI, 0.7-3.7/1000); for RSV, the rate was 0.8/1000 (95% CI, 0-1.7/1000) with a case-fatality ratio of 1.8%. Never breastfeeding, malnutrition, younger than 6 months, congenital heart disease, and lower hematocrit were risk factors for RF. Experiencing pneumonia, pneumothorax, sepsis, or apnea were clinical determinants of poor outcomes. Conclusions. Premature children under 2 years old in vulnerable environments experience RF and death more often than term counterparts. Modifiable risk factors associated with poor outcomes should prompt evidence-based interventions.Fil: Ofman, Gaston. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Pradarelli, Brad. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Caballero, Mauricio Tomás. Fundacion de Endocrinologia Infantil.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bianchi, Alejandra. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Grimaldi, Luciano Alva. Gobierno de la Provincia de Buenos Aires. Hospital Zonal General de Agudos Doctor Lucio Melendez.; ArgentinaFil: Sancilio, Andrea. Gobierno de la Provincia de Buenos Aires. Hospital Interzonal de Agudos Evita; ArgentinaFil: Duenas, Karina. Gobierno de la Provincia de Buenos Aires. Hospital Interzonal de Agudos Evita; ArgentinaFil: Rodriguez, Andrea. Gobierno de la Provincia de Buenos Aires. Hospital Provincial Evita Pueblo.; ArgentinaFil: Ferrero, Fernando. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Ferretti, Adrian. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Coviello, Silvina Andrea. Fundacion de Endocrinologia Infantil.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ferolla, Fausto Martín. Fundacion de Endocrinologia Infantil.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Acosta, Patricio Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Bergel, Eduardo. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Libster, Romina Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundacion de Endocrinologia Infantil.; ArgentinaFil: Polack, Fernando Pedro. Fundacion de Endocrinologia Infantil.; Argentin

International Nosocomial Infection Control Consortium (INICC) report, data summary of 36 countries, for 2004-2009

The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright (C) 2011 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved

Características clínico-epidemiológicas de pacientes hipertensos en un Consultorio Médico de Santa Clara

High blood pressure is a chronic non-transmittable disease, which is also a risk factor for the development of other clinical conditions. The incidence of arterial hypertension in the Cuban population is high.Aim: to characterize the evolution of arterial hypertension in a Family Doctor's Office.Methods: an observational, descriptive and cross-sectional study was carried out at the Family Doctor's Office 17-19 in the municipality of Santa Clara. The study covered the months of January to March 2020. Of the 256 hypertensive patients, a sample of 52 was selected by a simple random method.Results: Males predominated (53.84 %), together with the age group between 40 and 49 years (28.84 %). A total of 63.46 % of the patients were white-skinned. 51.61% presented risk factors. The risk factors with the highest incidence were smoking, followed by obesity and sedentary lifestyle.Conclusions: the most affected hypertensive patients are male. Most patients have a family history of high blood pressure. Smoking is a high incidence risk factor in the hypertensive population.Introducción: la hipertensión arterial es una enfermedad crónica no transmisible, que a la vez constituye un factor de riesgo para el desarrollo de otras enfermedades. La incidencia de la hipertensión arterial en la población de Cuba es alta.Objetivo: caracterizar el comportamiento de la hipertensión arterial en un Consultorio Médico de Familia.Métodos: se realizó un estudio observacional, descriptivo y transversal en el Consultorio Médico de Familia 17-19 del municipio Santa Clara. El período de estudio comprendió los meses de enero a marzo del 2020. La población fue de 256 hipertensos y se escogió una muestra de 52 hipertensos por muestreo aleatorio simple.Resultados: predominó el sexo masculino (53,84 %), y el grupo de edad entre 40 y 49 años (28,84 %). El 63,46 % de los pacientes fueron de color de la piel blanca. El 51,61 % presentaron factores de riesgo. Los factores de riesgo de mayor incidencia fueron el tabaquismo, seguido por la obesidad y el sedentarismo.Conclusiones: los pacientes hipertensos más afectados son los del sexo masculino. La mayor parte de los pacientes tienen antecedentes familiares de hipertensión arterial. El tabaquismo es un factor de riesgo de alta incidencia en la población hipertensa

A highly-accurate low-power CMOS potentiostat for implantable biosensors

Current-mirror-based potentiostats suffer from systematic and random errors causing offset, gain and linearity error in reading out the sensor data. In this work, a new potentiostat topology is proposed to eliminate the systematic error via an error-cancellation loop. The loop takes advantage of an error-tracking amplifier connected to a transimpedance amplifier with adjustable input common-mode voltage. Due to the enhanced loop gain, the potentiostat is able to accurately copy the sensor current which will then be converted into the proportional voltage. Additionally, a theoretical discussion of the proposed topology is given and a thorough study on the effect of random error sources is carried out. The potentiostat is designed and simulated in a 150nm CMOS process. The results verify a highly-linear highly-accurate performance in a low-noise condition, while consuming only 32 μW.Peer Reviewe

A highly-accurate low-power CMOS potentiostat for implantable biosensors

Current-mirror-based potentiostats suffer from systematic and random errors causing offset, gain and linearity error in reading out the sensor data. In this work, a new potentiostat topology is proposed to eliminate the systematic error via an error-cancellation loop. The loop takes advantage of an error-tracking amplifier connected to a transimpedance amplifier with adjustable input common-mode voltage. Due to the enhanced loop gain, the potentiostat is able to accurately copy the sensor current which will then be converted into the proportional voltage. Additionally, a theoretical discussion of the proposed topology is given and a thorough study on the effect of random error sources is carried out. The potentiostat is designed and simulated in a 150nm CMOS process. The results verify a highly-linear highly-accurate performance in a low-noise condition, while consuming only 32 μW.Peer Reviewe

RF performance projections of graphene FETs vs. silicon MOSFETs

A graphene field-effect-transistor (GFET) model calibrated with extracted device parameters and a commercial 65 nm silicon MOSFET model are compared with respect to their radio frequency behavior. GFETs slightly lag behind CMOS in terms of speed despite their higher mobility. This is counterintuitive, but can be explained by the effect of a strongly nonlinear voltage-dependent gate capacitance. GFETs achieve their maximum performance only for narrow ranges of VDS and IDS, which must be carefully considered for circuit design. For our parameter set, GFETs require at least μ = 3000 cm2 V−1 s−1 to achieve the same performance as 65 nm silicon MOSFETs.Peer Reviewe

Mathematics Academic Performance: It’s Relationship to Attitudes and Engagement in Online Learning

The current study examined the relationship between students’ attitudes and engagement and academic performance in mathematics online learning. The study used modified survey questionnaires adopted from Langat (2015). Davis (2014), Hart et al, (2011). The respondents are the 99 randomly selected pre-service teachers who are taking their Mathematics courses online. The respondents are moderately engaged in mathematics online learning. More specifically, students always have ready assignment and are cooperative and work with other students when doing online activities. However, it is found that respondents are somewhat disengaged and lack motivation whenever facing trouble in understanding a problem. The majority of respondents have a moderately positive attitude toward mathematics online learning. Students’ engagement and attitude in mathematics online learning are significantly correlated with academic performance. The significant correlation between students’ academic performance and attitude and engagement in mathematics online learning suggests that teachers may provide more opportunities for students to enable and extend their engagement and attitude in the teaching and learning process. It may allow to meet the positive effect that can contribute to an improvement of academic performance of students. Teachers may need to motivate their students to participate more in understanding math problems, to give their best, and to be more focused in class discussion. Teachers need to give more support to students who are very anxious in online classes and be more considerate to students who are having a hard time on this platform. Students may maximize the use of technology that could inspire them to become more academically motivated, engaged, and show positive attitude with regards to Mathematics online learning and to come up with their own relevant approaches

Care of patients with Huntington's disease in South America: a survey

Huntington's disease (HD) is a rare neurodegenerative disease with a multitude of symptoms, which requires access to specialized multidisciplinary care for adequate management. The aim of this study was to survey the characteristics of care in various HD centers in South America (SA). Methods A questionnaire was sent to 24 centers involved in the care for HD patients in SA. Results Of the total 24 centers, 19 (79.2%) are academic units. The majority of centers (62.5%) are general movement disorders clinics. Multidisciplinary care is available in 19 (79.2%) centers and in 20 (83.3%) care is provided free of charge. Genetic testing and counseling are available in 25 and 66.6% of centers, respectively. The majority of centers (83.3%) have no institutional support for end-stage care. Conclusions Although HD centers in SA are committed to providing multidisciplinary care, access to genetic counseling and end-stage care are lacking in most centers