Design of a Load Modulated Balanced Amplifier for sub-6GHz 5G Communications

L’oggetto della presente tesi consiste nell’analisi teorica, la progettazione e la verifica sperimentale di un Load Modulated Balanced Amplifier (LMBA). Si tratta di un amplificatore a radio frequenza il cui obiettivo è mantenere dei livelli di efficienza elevati anche quando la potenza di uscita assume valori più bassi del picco di 6-8 dB. Questo si ottiene attraverso l’introduzione di un segnale di controllo esterno nella porta normalmente isolata del coupler di uscita di un Balanced Amplifier. Dopo una prima spiegazione teorica del funzionamento di un LMBA, la progettazione di tale amplificatore verrà affrontata in tre fasi: verra` illustrato il progetto di un semplice amplificatore costituito da un singolo transistor, successivamente sarà sviluppato in Balanced Amplifier (BA) e infine si otterrà un LMBA attraverso l’utilizzo di un segnale di controllo. Ciascun amplificatore `e stato simulato attraverso il software ADS prima di essere realizzato sul substrato ROGERS RO4350. L’intero studio presentato nel seguito è stato condotto presso la sede olandese della Gallium Semiconductor utilizzando i transistor GT010D progettati dalla azienda in tecnologia GaN on SiC

A Preliminary Study

Bioelectrical Impedance Spectroscopy (BIS) allows assessing the composition of body districts noninvasively and quickly, potentially providing important physiological/clinical information. However, neither portable commercial instruments nor more advanced wearable prototypes simultaneously satisfy the demanding needs of unobtrusively tracking body fluid shifts in different segments simultaneously, over a broad frequency range, for long periods and with high measurements rate. These needs are often required to evaluate exercise tests in sports or rehabilitation medicine, or to assess gravitational stresses in aerospace medicine. Therefore, the aim of this work is to present a new wearable prototype for monitoring multi-segment and multi- frequency BIS unobtrusively over long periods. Our prototype guarantees low weight, small size and low power consumption. An analog board with current- injecting and voltage-sensing electrodes across three body segments interfaces a digital board that generates square-wave current stimuli and computes impedance at 10 frequencies from 1 to 796 kHz. To evaluate the information derivable from our device, we monitored the BIS of three body segments in a volunteer before, during and after physical exercise and postural shift. We show that it can describe the dynamics of exercise-induced changes and the effect of a sit-to-stand maneuver in active and inactive muscular districts separately and simultaneously

Tertiary nutrient removal from wastewater by immobilised microalgae: impact of wastewater nutrient characteristics and hydraulic retention time (HRT)

Immobilising microalgal cells has been proposed as a process solution to overcome the barriers associated with the implementation of microalgae for wastewater remediation. This work evaluated the performance and remediation mechanisms of immobilised microalgae for continuous wastewater treatment under varying hydraulic retention times (HRT). Three domestic secondary wastewaters with differing concentrations of orthophosphate (PO4-P), ammonium (NH4-N) and nitrate (NO3-N) were treated by Scenedesmus obliquus immobilised within 2% calcium alginate. Trials were run in continuous operation at HRTs of 3, 6, 12 and 20 h. Removal rates for PO4-P improved with increasing HRT, with minimum residual concentrations of 0.3–3.1 mg·L−1 observed at 3 h and 0.01–0.2 mg·L−1 at 20 h. Ammonium remediation was not linked to HRT or NH4+ concentration with minimum residual concentrations of <0.001 mg·L−1. Reduction in NO3-N improved with increasing HRT, with minimum residual concentrations of ≤19.3 at 3 h and ≤0.4 mg·L−1 at 20 h. Remediation was achieved through a combination of mechanisms including biological uptake and precipitation as a by-product of photosynthesis and nutrient metabolism. As such, immobilised microalgae have been proven to be an effective alternative solution for PO43− and NH4+ remediation of wastewater effluents at HRTs of 6–12 h

Intermediate acting non-depolarizing neuromuscular blocking agents and risk of postoperative respiratory complications: prospective propensity score matched cohort study

Objective: To determine whether use of intermediate acting neuromuscular blocking agents during general anesthesia increases the incidence of postoperative respiratory complications. Design: Prospective, propensity score matched cohort study. Setting: General teaching hospital in Boston, Massachusetts, United States, 2006-10. Participants: 18 579 surgical patients who received intermediate acting neuromuscular blocking agents during surgery were matched by propensity score to 18 579 reference patients who did not receive such agents. Main outcome measures: The main outcome measures were oxygen desaturation after extubation (hemoglobin oxygen saturation 3%) and reintubations requiring unplanned admission to an intensive care unit within seven days of surgery. We also evaluated effects on these outcome variables of qualitative monitoring of neuromuscular transmission (train-of-four ratio) and reversal of neuromuscular blockade with neostigmine to prevent residual postoperative neuromuscular blockade. Results: The use of intermediate acting neuromuscular blocking agents was associated with an increased risk of postoperative desaturation less than 90% after extubation (odds ratio 1.36, 95% confidence interval 1.23 to 1.51) and reintubation requiring unplanned admission to an intensive care unit (1.40, 1.09 to 1.80). Qualitative monitoring of neuromuscular transmission did not decrease this risk and neostigmine reversal increased the risk of postoperative desaturation to values less than 90% (1.32, 1.20 to 1.46) and reintubation (1.76, 1.38 to 2.26). Conclusion: The use of intermediate acting neuromuscular blocking agents during anesthesia was associated with an increased risk of clinically meaningful respiratory complications. Our data suggest that the strategies used in our trial to prevent residual postoperative neuromuscular blockade should be revisited

Factores relacionados con osteoartritis en trabajadores informales del centro de Medellín, Colombia

Introduction: A correlation is made regarding osteoarthrosis and working conditions and lifestyles of informal workers in Medellin downtown. Objective: To identify the prevalence of chronic and degenerative diseases, and the relationship of osteoarthritis with sociodemographic and work conditions, habits and lifestyles, in a group of informal workers from Medellín, Colombia. Materials and methods: Cross-sectional study, with a primary source of information, with 686 workers. An assisted survey was applied, after obtaining consent. 289 workers with a diagnosis of chronic or degenerative disease, ≥18 years old, with ≥5 years in their profession were included. Exploratory and association analysis with Chi2 test, and calculation of PR with 95% CI. Results: 79.9% of them suffered from a chronic disease. 3.46% had a diagnosis of osteoarthrosis, being significantly higher (p &lt;0.05) in those who had spent between 21 and 30 years performing their profession (PR=5,62.CI:1,20;26,34). The prevalence of osteoarthrosis was also higher in; &gt;45 years (PR=2.26), women (PR=4,44), sedentary workers (PR=1,71), obese (PR=3,40), as well as those who had been brick-layers (PR=1,30), in those who had semi-stationary sales positions (PR=2,21), they sold harvest and perishable products (PR=1,78), in those who worked&gt; 8 hours a day (PR:2,77), ≤ 5 days a week (PR=3,10), they did not have enough space to move (PR = 2.08), and in those who had forced postures or movements (PR=2,72). Conclusion: sociodemographic and work factors, habits and modifiable lifestyles are related to a higher prevalence of osteoarthrosis in this working population.Introducción: Se hace una correlación entre la osteoatrosis y &nbsp;las condiciones laborales, hábitos y estilos de vida de los trabajadores informales del centro de Medellín, Colombia. Objetivo: Identificar la relación de la osteoartritis y la prevalencia de enfermedades crónicas y degenerativas con las condiciones sociodemográficas, laborales, hábitos y estilos de vida en un grupo de trabajadores informales de Medellín, Colombia. Materiales y métodos: Estudio transversal, con fuente primaria de información &nbsp;de 686 trabajadores informales. &nbsp;Se realizó una encuesta asistida, previa toma de consentimiento. Se seleccionaron &nbsp;289 trabajadores con diagnóstico de enfermedad crónica o degenerativa, ≥18 años, con ≥5 años en su oficio. Se realizaron análisis exploratorios y de asociación con prueba Chi2, y cálculo de RP con IC del 95%. Resultados: el 79,9% de la población padecía alguna enfermedad crónica. El 3,46% presentaba diagnóstico de osteoartritis, siendo significativamente mayor (p&lt;0,05) en quienes tenían entre 21 y 30 años en su oficio (RP=5,62. IC:1,20;26,34). También fue mayor la prevalencia de osteoartritis en; &gt;45 años (RP=2,26), mujeres (RP:4,44), trabajadores sedentarios (RP=1,71), obesos (RP=3,40), así como en quienes habían sido obreros (RP=1,30), en aquellos que tenían puestos de venta semiestacionaria (RP=2,21), vendían productos de cosecha y perecederos (RP=1,78), en quienes trabajaban &gt;8 horas diarias (RP:2,77),&nbsp; ≤5días a la semana (RP=3,10), no tenían espacio suficiente para moverse (RP=2,08), y en quienes tenían posturas o movimientos forzados (RP=2,72). Conclusión: En la población de vendedores informales del centro de Medellín, los factores sociodemográficos, laborales, hábitos y estilos de vida modificables se relacionan con una &nbsp;mayor prevalencia de osteoartritis

Factores relacionados con osteoartritis en trabajadores informales del centro de Medellín, Colombia

Introduction: A correlation is made regarding osteoarthrosis and working conditions and lifestyles of informal workers in Medellin downtown. Objective: To identify the prevalence of chronic and degenerative diseases, and the relationship of osteoarthritis with sociodemographic and work conditions, habits and lifestyles, in a group of informal workers from Medellín, Colombia. Materials and methods: Cross-sectional study, with a primary source of information, with 686 workers. An assisted survey was applied, after obtaining consent. 289 workers with a diagnosis of chronic or degenerative disease, ≥18 years old, with ≥5 years in their profession were included. Exploratory and association analysis with Chi2 test, and calculation of PR with 95% CI. Results: 79.9% of them suffered from a chronic disease. 3.46% had a diagnosis of osteoarthrosis, being significantly higher (p &lt;0.05) in those who had spent between 21 and 30 years performing their profession (PR=5,62.CI:1,20;26,34). The prevalence of osteoarthrosis was also higher in; &gt;45 years (PR=2.26), women (PR=4,44), sedentary workers (PR=1,71), obese (PR=3,40), as well as those who had been brick-layers (PR=1,30), in those who had semi-stationary sales positions (PR=2,21), they sold harvest and perishable products (PR=1,78), in those who worked&gt; 8 hours a day (PR:2,77), ≤ 5 days a week (PR=3,10), they did not have enough space to move (PR = 2.08), and in those who had forced postures or movements (PR=2,72). Conclusion: sociodemographic and work factors, habits and modifiable lifestyles are related to a higher prevalence of osteoarthrosis in this working population.Introducción: Se hace una correlación entre la osteoatrosis y &nbsp;las condiciones laborales, hábitos y estilos de vida de los trabajadores informales del centro de Medellín, Colombia. Objetivo: Identificar la relación de la osteoartritis y la prevalencia de enfermedades crónicas y degenerativas con las condiciones sociodemográficas, laborales, hábitos y estilos de vida en un grupo de trabajadores informales de Medellín, Colombia. Materiales y métodos: Estudio transversal, con fuente primaria de información &nbsp;de 686 trabajadores informales. &nbsp;Se realizó una encuesta asistida, previa toma de consentimiento. Se seleccionaron &nbsp;289 trabajadores con diagnóstico de enfermedad crónica o degenerativa, ≥18 años, con ≥5 años en su oficio. Se realizaron análisis exploratorios y de asociación con prueba Chi2, y cálculo de RP con IC del 95%. Resultados: el 79,9% de la población padecía alguna enfermedad crónica. El 3,46% presentaba diagnóstico de osteoartritis, siendo significativamente mayor (p&lt;0,05) en quienes tenían entre 21 y 30 años en su oficio (RP=5,62. IC:1,20;26,34). También fue mayor la prevalencia de osteoartritis en; &gt;45 años (RP=2,26), mujeres (RP:4,44), trabajadores sedentarios (RP=1,71), obesos (RP=3,40), así como en quienes habían sido obreros (RP=1,30), en aquellos que tenían puestos de venta semiestacionaria (RP=2,21), vendían productos de cosecha y perecederos (RP=1,78), en quienes trabajaban &gt;8 horas diarias (RP:2,77),&nbsp; ≤5días a la semana (RP=3,10), no tenían espacio suficiente para moverse (RP=2,08), y en quienes tenían posturas o movimientos forzados (RP=2,72). Conclusión: En la población de vendedores informales del centro de Medellín, los factores sociodemográficos, laborales, hábitos y estilos de vida modificables se relacionan con una &nbsp;mayor prevalencia de osteoartritis

Advanced stabilization methods of plasma devices for plasma-based acceleration

Towards the next generation of compact plasma-based accelerators, useful in several fields, such as basic research, medicine and industrial applications, a great effort is required to control the plasma creation, the necessity of producing a time-jitter free channel, and its stability namely uniformity and reproducibility. In this Letter, we describe an experimental campaign adopting a gas-filled discharge-capillary where the plasma and its generation are stabilized by triggering its ignition with an external laser pulse or an innovative technique based on the primary dark current (DC) in the accelerating structure of a linear accelerator (LINAC). The results show an efficient stabilization of the discharge pulse and plasma density with both pre-ionizing methods turning the plasma device into a symmetrical stable accelerating environment, especially when the external voltage is lowered near the breakdown value of the gas. The development of tens of centimeter long capillaries is enabled and, in turn, longer acceleration lengths can be adopted in a wide range of plasma-based acceleration experiments

Phosphodiesterases S-sulfhydration contributes to human skeletal muscle function

The increase in intracellular calcium is influenced by cyclic nucleotides (cAMP and cGMP) content, which rating is governed by phosphodiesterases (PDEs) activity.Despite it has been demonstrated a beneficial effect of PDEs inhibitors in different pathological conditions involving SKM, not much is known on the role exerted by cAMP-cGMP/PDEs axis in human SKM contractility. Here, we show that Ssulfhydration of PDEs modulates human SKM contractility in physiological and pathological conditions. Having previously demonstrated that, in the rare human syndrome Malignant Hyperthermia (MH), there is an overproduction of hydrogen sulfide (H2S) within SKM contributing to hyper-contractility, here we have used MH negative diagnosed biopsies (MHN) as healthy SKM, and MH susceptible diagnosed biopsies (MHS) as a pathological model of SKM hypercontractility. The study has been performed on MHS and MHN human biopsies after diagnosis has been made and on primary SKM cells derived from both MHN and MHS biopsies. Our data demonstrate that in normal conditions PDEs are S-sulfhydrated in both quadriceps' biopsies and primary SKM cells. This post translational modification (PTM) negatively regulates PDEs activity with consequent increase of both cAMP and cGMP levels. In hypercontractile biopsies, due to an excessive H2S content, there is an enhanced Ssulfhydration of PDEs that further increases cyclic nucleotides levels contributing to SKM hyper-contractility. Thus, the identification of a new endogenous PTM modulating PDEs activity represents an advancement in SKM physiopathology understanding