Regulating the load voltage is of major importance for ensuring high transmission efficiency in wireless power transfer (WPT) systems. In this context, this work presents a novel control strategy ...applied in the dc-ac converter used in the primary side of a WPT system. The performance of a class-DE resonant inverter is investigated considering that such topology presents inherent soft-switching characteristics, thus implying reduced switching losses. The controller relies on an autoregressive with exogenous output (ARX) model based on an adaptive linear neuron (ADALINE) network, which allows for determining the turn-on time of the active switches accurately while providing the system with the ability to adapt to distinct alignment conditions. The performance of the proposed controller is compared with that of a linear controller, which does not prove to be an effective solution if misalignment occurs.
En la actualidad la regulación de voltaje en las redes de distribución toma un rol importante para el crecimiento económico de un país y progreso humano, dada a que una buena calidad de servicio ...eléctrico entregada a los usuarios finales provoca un efecto directo en la productividad de las industrias, la educación, salud, servicios de comunicación y abastecimiento de agua potable. En este artículo se plantea una solución a corto plazo al problema de bajo voltaje en redes de media tensión, con el ingreso óptimo de equipos de regulación de voltaje por medio de un algoritmo genético en Matlab que evaluará los parámetros eléctricos de la red antes y después de instalar los equipos de compensación, cumpliendo con la regulación vigente Arconel 005/18 en el sector eléctrico ecuatoriano.
Induction heating is regarded as a clean cooking technology, whose prominent advantages include contactless energy transfer, controllable heating rate, and safety. In household applications, it is ...expected that this approach is supposed to replace conventional gas stoves aiming at a more sustainable future. The increase of energy consumption associated with this trend cannot be neglected, while distributed generation (DG) stands out as a prominent solution to mitigate the impact on the power system. In this context, this work presents an induction heating system consisting of the integration of power electronic converters and a grid-connected photovoltaic (PV) system. Based on existing solutions available in the literature, it is possible to supply the induction stove with two distinct energy sources: the ac grid and PV modules. A high-voltage step-up dc–dc boost converter is employed to create a dc link responsible for connecting the PV system to the grid. The dc link is also used to supply a class DE parallel resonant inverter associated with the induction stove, which requires a low component count. Besides, the PV modules are capable of providing up to 3 kW under standard test conditions. Thus, part of the generated energy is used to supply the heating system, while the remaining portion is injected into the grid. Simulation results are presented to assess the performance of the whole system in steady-state and transient conditions, demonstrating that it is capable of operating at the maximum power point and injecting nearly sinusoidal currents with high power factor.
To analyse the characteristics and predictors of death in hospitalized patients with coronavirus disease 2019 (COVID-19) in Spain.
A retrospective observational study was performed of the first ...consecutive patients hospitalized with COVID-19 confirmed by real-time PCR assay in 127 Spanish centres until 17 March 2020. The follow-up censoring date was 17 April 2020. We collected demographic, clinical, laboratory, treatment and complications data. The primary endpoint was all-cause mortality. Univariable and multivariable Cox regression analyses were performed to identify factors associated with death.
Of the 4035 patients, male subjects accounted for 2433 (61.0%) of 3987, the median age was 70 years and 2539 (73.8%) of 3439 had one or more comorbidity. The most common symptoms were a history of fever, cough, malaise and dyspnoea. During hospitalization, 1255 (31.5%) of 3979 patients developed acute respiratory distress syndrome, 736 (18.5%) of 3988 were admitted to intensive care units and 619 (15.5%) of 3992 underwent mechanical ventilation. Virus- or host-targeted medications included lopinavir/ritonavir (2820/4005, 70.4%), hydroxychloroquine (2618/3995, 65.5%), interferon beta (1153/3950, 29.2%), corticosteroids (1109/3965, 28.0%) and tocilizumab (373/3951, 9.4%). Overall, 1131 (28%) of 4035 patients died. Mortality increased with age (85.6% occurring in older than 65 years). Seventeen factors were independently associated with an increased hazard of death, the strongest among them including advanced age, liver cirrhosis, low age-adjusted oxygen saturation, higher concentrations of C-reactive protein and lower estimated glomerular filtration rate.
Our findings provide comprehensive information about characteristics and complications of severe COVID-19, and may help clinicians identify patients at a higher risk of death.
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The COVID-19 pandemic affected older adults worldwide. Sedentary older adults experienced more severe adverse health effects due to their shelter-in-place. Physical activity was strongly recommended ...during periods of social distancing. The present study evaluated the impact of a virtually supervised exercise program on the physical fitness and mental health of Mexican older adults during the pandemic's lockdown.
Participants were 44 older adults who were assigned to one of four physical fitness groups: a healthy control group (Ctrl-H,
= 15), a comorbidity control group (Ctrl-COM,
= 9), an exercise group without comorbidities (Exe-H,
= 11), and an exercise group with comorbidities (Exe-COM,
= 9). The participants engaged in a 60-min, virtually-supervised concurrent exercise session three times/week for 12 weeks. Fitness was measured using the online Senior Fitness Tests and the 4-m Gait Speed Test. Mental health was evaluated through virtual interviews using the Hamilton Depression Rating Scale, the Geriatric Depression Scale, and the Connor-Davidson Resilience Scale. Within-subject pre vs. post-intervention comparisons tested for significant differences, between-groups and over time.
Significant interactions were found in the scores of the Geriatric Depression Scale (
≤ 0.0001; η
= 0.35), the Hamilton Depression Scale (
≤ 0.0001; η
= 0.35), resilience scores (
≤ 0.0001; η
= 0.46), lower-body strength (
≤ 0.0001; η
= 0.32), timed up-and-go test (
= 0.018; η
= 0.18), the 6MWT distance scores (
≤ 0.0001; η
= 0.39), and the 4-m gait speed test scores (
= 0.011; η
= 0.20).
A long-term virtually-supervised exercise program conducted during the COVID-19 lockdown period led to marked improvements in both the fitness and mental health of older Mexican adults. Comorbidities did not diminish these benefits. These findings provide empirical support for online exercise programs in the daily routines of older adults to make clinically meaningful improvements in both physical and mental well-being.
Background
Information is lacking regarding long-term survival and predictive factors for mortality in patients with acute hypoxemic respiratory failure due to coronavirus disease 2019 (COVID-19) and ...undergoing invasive mechanical ventilation. We aimed to estimate 180-day mortality of patients with COVID-19 requiring invasive ventilation, and to develop a predictive model for long-term mortality.
Methods
Retrospective, multicentre, national cohort study between March 8 and April 30, 2020 in 16 intensive care units (ICU) in Spain. Participants were consecutive adults who received invasive mechanical ventilation for COVID-19. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection detected in positive testing of a nasopharyngeal sample and confirmed by real time reverse-transcriptase polymerase chain reaction (rt-PCR). The primary outcomes was 180-day survival after hospital admission. Secondary outcomes were length of ICU and hospital stay, and ICU and in-hospital mortality. A predictive model was developed to estimate the probability of 180-day mortality.
Results
868 patients were included (median age, 64 years interquartile range IQR, 56–71 years; 72% male). Severity at ICU admission, estimated by SAPS3, was 56 points IQR 50–63. Prior to intubation, 26% received some type of noninvasive respiratory support. The unadjusted overall 180-day survival rates was 59% (95% CI 56–62%). The predictive factors measured during ICU stay, and associated with 180-day mortality were: age Odds Ratio OR per 1-year increase 1.051, 95% CI 1.033–1.068)), SAPS3 (OR per 1-point increase 1.027, 95% CI 1.011–1.044), diabetes (OR 1.546, 95% CI 1.085–2.204), neutrophils to lymphocytes ratio (OR per 1-unit increase 1.008, 95% CI 1.001–1.016), failed attempt of noninvasive positive pressure ventilation prior to orotracheal intubation (OR 1.878 (95% CI 1.124–3.140), use of selective digestive decontamination strategy during ICU stay (OR 0.590 (95% CI 0.358–0.972) and administration of low dosage of corticosteroids (methylprednisolone 1 mg/kg) (OR 2.042 (95% CI 1.205–3.460).
Conclusion
The long-term survival of mechanically ventilated patients with severe COVID-19 reaches more than 50% and may help to provide individualized risk stratification and potential treatments.
Trial registration
: ClinicalTrials.gov Identifier:
NCT04379258.
Registered 10 April 2020 (retrospectively registered)
The 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing power (FRAP), and semivolatile compounds of Conyza bonariensis L. leave extract and fractions are discussed. A methanolic crude extract was ...obtained through maceration, and subsequently, n-hexane, chloroform, and ethyl acetate fractions were collected using a solvent-solvent partition. Total phenols, flavonoids, and antioxidant activity assays were performed in an ultraviolet-visible (UV-Vis) spectrophotometer, and the results were expressed as Gallic Acid, Quercetin, and Trolox equivalents respectively. The findings achieved indicate that ethyl acetate fraction showed the highest DPPH radical scavenging capacity (90.69±3.16%) at 500 µg mL-1, and reduced the ferric tripyridyltriazine complex (Fe3+-TPTZ) with values between 19.68 and 2,355.37 mg Trolox equivalent (TE) g-1. It was identified 28 phytoconstituents through Gas chromatography-mass spectrometry (GC-MS). The scavenging activity of ethyl acetate fraction could be correlated mostly to the presence of eugenol, trans-isoeugenol, lucenin-2, methyl salicylate, and syringic acid. This study reveals that the ethyl acetate fraction could be used as a good source of antioxidants for health benefits.
Fosfomycin is currently a viable option against urinary tract infections, particularly against extended-spectrum β-lactamases (ESBL)-producing E. coli, due to its unique mechanism of action and its ...low resistance among bacteria. The objective of this study was to investigate two of the three most common mechanisms of resistance against this antibiotic among 350 ESBL-producing E. coli strains isolated from the urine of Mexican patients. The prevalence of fosfomycin resistance in our study was 10.9% (38/350). Of all resistant isolates analyzed, 23 (60.5%) were identified as fos-producing organisms, with 14 strains carrying fosA3 and 9, fosA1. Additionally, 11 (28.9%) fosfomycin-resistant isolates presented resistance due to impaired antibiotic transport and 8 (21.0%) both mechanisms. No resistance mechanism investigated in the study was found on 12 strains. All 38 confirmed ESBL-producing isolates carried a blaCTX-M subtype, 36 (94.5%) belonged to the O25b-ST131 clone, and all of them were able to transfer the fosfomycin resistance trait to recipient strains horizontally. This is the first study in Mexico demonstrating a plasmid-mediated fosfomycin resistance mechanism among clinical E. coli strains. Since our results suggest a strong association among fos and blaCTX-M genes and ST131 clones in uropathogenic E. coli, plasmid-mediated fosfomycin resistance should be closely monitored.
•Orthohantaviruses are still a significant public health threat in endemic countries, with high case fatality rates (CFR).•We report the findings of 40 laboratory-confirmed cases diagnosed in two ...departments of Bolivia (Santa Cruz and Tarija) during 2018.•More than half of the patients (57.5%) were admitted to the intensive care unit and had cardiopulmonary compromise, with 83% of these presenting acute respiratory distress syndrome; of these, 89.5% required mechanical ventilation.•Six patients died (CFR 15%); those <15 or >60 years of age were more prone to die (odds ratio 10.33, 95% confidence interval 1.411–75.694), as were those with comorbidities (odds ratio 16.5, 95% confidence interval 1.207–225.540).•Orthohantaviruses led to a high CFR in areas prone to certain eco-epidemiological conditions (including the presence of rodents) for viral transmission and the risk of spillover to humans due to social, environmental, and occupational factors.
Orthohantaviruses are still a significant public health threat in endemic countries, with high case fatality rates (CFR). In Bolivia, the reporting of small outbreaks occurred until 2012. The findings of 40 laboratory-confirmed cases diagnosed in two departments are reported herein.
This was an observational, retrospective and cross-sectional study. Data on laboratory-confirmed cases in 2018 were collected from the hospitals and departmental health services (SEDES) of Santa Cruz and Tarija. An ELISA was used for the detection of IgM antibody to hantavirus in the patient blood samples.
Forty patients were IgM-positive. The median age of the patients was 24 years (interquartile range 19–41 years) and 72.5% were male. All patients were hospitalized; 57.5% were admitted to the intensive care unit and had cardiopulmonary compromise, with 83% of these presenting acute respiratory distress syndrome and 89.5% of these requiring mechanical ventilation. Six patients died (CFR 15%). Patients <15 or >60 years old were more prone to die (odds ratio 10.33, 95% confidence interval 1.411–75.694), as were those with comorbidities (odds ratio 16.5, 95% confidence interval 1.207–225.540).
Orthohantavirus infections were associated with a high CFR. These cases occurred in areas with eco-epidemiological conditions facilitating viral transmission, including the presence of rodents, as well as the risk of spillover to humans due to social, environmental, and occupational factors.
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