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Transition metal oxides are a great alternative to less expensive hydrogen evolution reaction (HER) catalysts. However, the lack of conductivity of these materials requires a conductor material to support them and improve the activity toward HER. On the other hand, carbon paste electrodes result in a versatile and cheap electrode with good activity and conductivity in electrocatalytic hydrogen production, especially when the carbonaceous material is agglomerated with ionic liquids. In the present work, an electrode composed of multi-walled carbon nanotubes (MWCNTs) and cobalt ferrite oxide (CoFe2O4) was prepared. These compounds were included on an electrode agglomerated with the ionic liquid N-octylpyridinium hexafluorophosphate (IL) to obtain the modified CoFe2O4/MWCNTs/IL nanocomposite electrode. To evaluate the behavior of each metal of the bimetallic oxide, this compound was compared to the behavior of MWCNTs/IL where a single monometallic iron or cobalt oxides were included (i.e., α-Fe2O3/MWCNTs/IL and Co3O4/MWCNTs/IL). The synthesis of the oxides has been characterized by X-ray diffraction (XRD), RAMAN spectroscopy, and field emission scanning electronic microscopy (FE-SEM), corroborating the nanometric character and the structure of the compounds. The CoFe2O4/MWCNTs/IL nanocomposite system presents excellent electrocatalytic activity toward HER with an onset potential of -270 mV vs. RHE, evidencing an increase in activity compared to monometallic oxides and exhibiting onset potentials of -530 mV and -540 mV for α-Fe2O3/MWCNTs/IL and Co3O4/MWCNTs/IL, respectively. Finally, the system studied presents excellent stability during the 5 h of electrolysis, producing 132 µmol cm-2 h-1 of hydrogen gas.
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Cobalto , Compostos Férricos , Hidrogênio , Líquidos Iônicos , Nanocompostos , Nanotubos de Carbono , Óxidos , Cobalto/química , Nanotubos de Carbono/química , Líquidos Iônicos/química , Nanocompostos/química , Catálise , Hidrogênio/química , Compostos Férricos/química , Óxidos/química , Eletrodos , Técnicas Eletroquímicas/métodos , Difração de Raios X , Análise Espectral RamanRESUMO
Cu2ZnSnSe4 (CZTSe) nanoparticles (NPs) were successfully synthesized via a solvothermal method. Their structural, compositional, morphological, optoelectronic, and electrochemical properties have been characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Field-emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), UV-vis absorption spectroscopy, and electrochemical impedance spectroscopy (EIS) techniques. Porosimetry and specific surface area in terms of the Brunauer-Emmett-Teller (BET) technique have also been studied. XRD indicates the formation of a polycrystalline kesterite CZTSe phase. Raman peaks at 173 and 190 cm-1 confirm the formation of a pure phase. TEM micrographs revealed the presence of nanoparticles with average sizes of ~90 nm. A BET surface area of 7 m2/g was determined. The CZTSe NPs showed a bandgap of 1.0 eV and a p-type semiconducting behavior. As a proof of concept, for the first time, the CZTSe NPs have been used as a visible-light-driven photocatalyst to Congo red (CR) azo dye degradation. The nanophotocatalyst material under simulated sunlight results in almost complete degradation (96%) of CR dye after 70 min, following a pseudo-second-order kinetic model (rate constant of 0.334 min-1). The prepared CZTSe was reusable and can be repeatedly used to remove CR dye from aqueous solutions.
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OBJECTIVES: There is currently a limited ability to accurately identify women at risk of postpartum hemorrhage (PPH). We conducted the "Predict-PPH" study to develop and evaluate an antepartum prediction model and its derived risk-scoring system. METHODS: This was a prospective cohort study of healthy pregnant women who registered and gave birth in five hospitals in Lagos, Nigeria, from January to June 2023. Maternal antepartum characteristics were compared between women with and without PPH. A predictive multivariable model was estimated using binary logistic regression with a backward stepwise approach eliminating variables when P was greater than 0.10. Statistically significant associations in the final model were reported when P was less than 0.05. RESULTS: The prevalence of PPH in the enrolled cohort was 37.1%. Independent predictors of PPH such as maternal obesity (adjusted odds ratio [aOR] 3.25, 95% confidence interval [CI] 2.47-4.26), maternal anemia (aOR 1.32, 95% CI 1.02-1.72), previous history of cesarean delivery (aOR 4.24, 95% CI 3.13-5.73), and previous PPH (aOR 2.65, 95% CI 1.07-6.56) were incorporated to develop a risk-scoring system. The area under the receiver operating characteristic curve (AUROC) for the prediction model and risk scoring system was 0.72 (95% CI 0.69-0.75). CONCLUSION: We recorded a relatively high prevalence of PPH. Our model performance was satisfactory in identifying women at risk of PPH. Therefore, the derived risk-scoring system could be a useful tool to screen and identify pregnant women at risk of PPH during their routine antenatal assessment for birth preparedness and complication readiness.
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Hemorragia Pós-Parto , Humanos , Feminino , Hemorragia Pós-Parto/epidemiologia , Nigéria/epidemiologia , Gravidez , Estudos Prospectivos , Adulto , Medição de Risco , Fatores de Risco , Prevalência , Adulto Jovem , Modelos Logísticos , Curva ROC , Estudos de CoortesRESUMO
This study evaluated the behavior of three paint systems exposed to the Antarctic marine environment for 45 months compared to a control of uncoated carbon steel with a determined corrosion rate. At the study site, all environmental conditions, solar radiation, and the concentration of environmental pollutants (Cl- and SO2) were evaluated. The paint systems differed in terms of the primer and top coat. Coated samples were studied before and after exposure. They were evaluated visually and using SEM to determine adhesion, abrasion, and contact angle; using the Evans X-Cut Tape Test; using ATR-FTIR spectroscopy to analyze the state of aging of the top layer; and using electrochemical impedance spectroscopy (EIS) for coat protection characterization. The corrosion rate obtained for steel was 85.64 µm year-1, which aligned with a C5 environmental corrosivity category. In general, the evaluation in the period studied showed the paint systems had good adhesion and resistance to delamination, without the presence of surface rust, and exhibited some loss of brightness, an increase in the abrasion index, and a decrease in the percentage of reflectance due to aging. EIS showed good protection capability of the three coating schemes. In general, this type of paint system has not previously been evaluated in an extreme environment after 45 months of exposure to the environment. The results showed that the best behavior was found for the system whose top layer was acrylic-aliphatic polyurethane.
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A binder-free CdCO3/CdO/Co3O4 compound with a micro-cube-like morphology on a nickel foam (NF) made via a facile two-step hydrothermal + annealing procedure has been developed. The morphological, structural and electrochemical behavior of both the single compounds constituting this final product and the final product itself has been studied. The synergistic contribution effect of the single compounds in the final compounded resulting specific capacitance values are presented and discussed. The CdCO3/CdO/Co3O4@NF electrode exhibits excellent supercapacitive performance with a high specific capacitance (C S) of 1.759 × 103 F g-1 at a current density of 1 mA cm-2 and a C S value of 792.3 F g-1 at a current density of 50 mA cm-2 with a very good rate capability. The CdCO3/CdO/Co3O4@NF electrode also demonstrates a high coulombic efficiency of 96% at a current density as high as 50 mA cm-2 and also exhibits a good cycle stability with capacitance retention of ca. 100% after 1000 cycles at a current density of 10 mA cm-2 along with a potential window of 0.4 V. The obtained results suggest that the facilely synthesized CdCO3/CdO/Co3O4 compound has great potential in high-performance electrochemical supercapacitor devices.
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A hydrothermal method was successfully employed to synthesize kesterite Cu2ZnSnS4 (CZTS) nanoparticles. X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and optical ultraviolet-visible (UV-vis) spectroscopy were used for characterization of structural, chemical, morphological, and optical properties. XRD results confirmed that a nanocrystalline CZTS phase corresponding to the kesterite structure was formed. Raman analysis confirmed the existence of single pure phase CZTS. XPS results revealed the oxidation states as Cu+, Zn2+, Sn4+, and S2-. FESEM and TEM micrograph images revealed the presence of nanoparticles with average sizes between 7 nm to 60 nm. The synthesized CZTS nanoparticles bandgap was found to be 1.5 eV which is optimal for solar photocatalytic degradation applications. The properties as a semiconductor material were evaluated through the Mott-Schottky analysis. The photocatalytic activity of CZTS has been investigated through photodegradation of Congo red azo dye solution under solar simulation light irradiation, proving to be an excellent photo-catalyst for CR where 90.2% degradation could be achieved in just 60 min. Furthermore, the prepared CZTS was reusable and can be repeatedly used to remove Congo red dye from aqueous solutions.
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OBJECTIVES: To improve antimicrobial prescribing behaviour of general practitioners in large-scale out-of-hours services for uncomplicated lower urinary tract infection (LUTI) in females aged 20-80 years, which is regarded as one of the most prevalent bacterial infections in primary care. METHODS: A quasi-experimental design was used in two regional large-scale out-of-hours services. A simple, multifaceted intervention was offered in a 16 week period in one region (the intervention region). During the two washout periods, at 5 and 17 months, we observed diagnoses and prescriptions. The main outcome measure was the share of appropriate and inappropriate prescriptions. RESULTS: The proportion of patients with LUTI ranged from 1.0% to 2.1%. The relative proportion of appropriate prescriptions in the intervention region increased from 26.9% to 69.4%, but decreased afterwards to 40.8%. CONCLUSIONS: A simple, multifaceted intervention for treatment of LUTI during out-of-hours care may improve the quality of antimicrobial prescribing, although the improvement may not be sustained in the longer term.
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Antibacterianos/uso terapêutico , Prescrições de Medicamentos/normas , Fidelidade a Diretrizes , Infecções Urinárias/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Medicina Geral/métodos , Humanos , Pessoa de Meia-Idade , Adulto JovemRESUMO
Silver nanoparticles (NPs) on glass substrates were obtained by a solid-state thermal dewetting (SSD) process using vacuum-evaporated-silver precursor layers. An exhaustive investigation of the morphological, structural, and surface chemistry properties by systematically controlling the precursor film thickness, annealing temperature, and time was conducted. Thin silver films with thicknesses of 40 and 80 nm were deposited and annealed in air by applying a combined heat-up+constant temperature-time program. Temperatures from 300 to 500 °C and times from 0 to 50 min were assayed. SSD promoted the morphological modification of the films, leading to the Ag NPs having a discrete structure. The size, shape, surface density, and inter-nanoparticle distance of the nanoparticles depended on the initial film thickness, annealing temperature, and time, exhibiting a cubic silver structure with a (111) preferred crystallographic orientation. The prepared NPs were found to be highly enriched in the Ag{111}/Ag{110}/Ag{100} equilibrium facets. SSD not only promotes NP formation but also promotes the partial oxidation from Ag to AgO at the surface level. AgO was detected on the surface around the nanoparticles synthesized at 500 °C. Overall, a broad framework has been established that connects process factors to distinguish resultant Ag NP features in order to develop unique silver nanoparticles for specific applications.
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This paper describes the health conditions in Ecuador and, in more detail, the characteristics of the Ecuadorian health system, including its structure and coverage, its financial sources, the physical, material and human resources available, and the stewardship activities developed by the Ministry of Public Health. It also describes the structure and content of its health information system, and the participation of citizens in the operation and evaluation of the health system. The paper ends with a discussion of the most recent policy innovations implemented in the Ecuadorian system, including the incorporation of a chapter on health into the new Constitution which recognizes the protection of health as a human right, and the construction of the Comprehensive Public Health Network.
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Atenção à Saúde/organização & administração , Administração de Serviços de Saúde , Participação da Comunidade/estatística & dados numéricos , Atenção à Saúde/economia , Atenção à Saúde/estatística & dados numéricos , Demografia , Equador , Organização do Financiamento/economia , Organização do Financiamento/organização & administração , Organização do Financiamento/estatística & dados numéricos , Programas Governamentais/economia , Programas Governamentais/organização & administração , Programas Governamentais/estatística & dados numéricos , Gastos em Saúde/estatística & dados numéricos , Recursos em Saúde/organização & administração , Recursos em Saúde/estatística & dados numéricos , Recursos em Saúde/provisão & distribuição , Serviços de Saúde/economia , Serviços de Saúde/estatística & dados numéricos , Administração de Serviços de Saúde/economia , Administração de Serviços de Saúde/estatística & dados numéricos , Indicadores Básicos de Saúde , Direitos Humanos/legislação & jurisprudência , Humanos , Serviços de Informação/organização & administração , Benefícios do Seguro/economia , Benefícios do Seguro/estatística & dados numéricos , Cobertura do Seguro/economia , Cobertura do Seguro/estatística & dados numéricos , Seguro Saúde/economia , Seguro Saúde/organização & administração , Seguro Saúde/estatística & dados numéricos , Programas Nacionais de Saúde/economia , Programas Nacionais de Saúde/organização & administração , Programas Nacionais de Saúde/estatística & dados numéricos , Inovação Organizacional , Setor Privado/economia , Setor Privado/organização & administração , Setor Privado/estatística & dados numéricos , Garantia da Qualidade dos Cuidados de Saúde/organização & administração , Previdência Social/economia , Previdência Social/organização & administração , Previdência Social/estatística & dados numéricos , Estatísticas VitaisRESUMO
A CdCO3/CdO/Co3O4 composite has been prepared on nickel foam through a combined hydrothermal-annealing method. An asymmetric hybrid supercapacitor (SC) device was assembled with this composite as the positive electrode and activated carbon was the negative electrode. The SC exhibited a high specific capacitance of 84 F g-1 @ 1 mA cm-2, a maximum energy density of 26.3 W h kg-1, and a power density of 2290 W kg-1, along with a wide potential window of 1.5 V and long cycle life (92% after 6000 cycles). SCs assembled in series powered various light-emitting diodes and moved an electrical mini-motor.
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La principal función del aparato respiratorio es permitir el intercambio gaseoso, el cual se produce en las unidades alveolares. Para definir y conocer la ventilación alveolar, es necesario estar familiarizado con los volúmenes y capacidades pulmonares, además de conocer los principios fisiológicos que nos permiten medirlos y/o estimarlos. El objetivo de este artículo es revisar estos conceptos, para aumentar el entendimiento de la fisiología del aparato respiratorio.
The main function of the respiratory system is to allow gas exchange, which occurs in the alveolar units. To define and know alveolar ventilation, it is necessary to be familiarized with lung volumes and capacities, in addition to understand the physiological principles that allow us measure and / or estimate them. The objective of this article is to review these concepts, to increase the understanding of the physiology of the respiratory system.
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Humanos , Respiração Artificial , Fenômenos Fisiológicos RespiratóriosRESUMO
Mind-wandering is the occasional distraction we experience while performing a cognitive task. It arises without any external precedent, varies over time, and interferes with the processing of sensory information. Here, we asked whether the transition from the on-task state to mind-wandering is a gradual process or an abrupt event. We developed a new experimental approach, based on the continuous, online assessment of individual psychophysical performance. Probe questions were asked whenever response times (RTs) exceeded 2 standard deviations from the participant's average RT. Results showed that mind-wandering reports were generally preceded by slower RTs, as compared to trials preceding on-task reports. Mind-wandering episodes could be reliably predicted from the response time difference between the last and the second-to-last trials. Thus, mind-wandering reports follow an abrupt increase in behavioral variability, lasting between 2.5 and 10 seconds.
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Atenção , Desempenho Psicomotor , Pensamento , Adolescente , Adulto , Atenção/fisiologia , Humanos , Masculino , Tempo de Reação , Pensamento/fisiologia , Adulto JovemRESUMO
BACKGROUND: Humans and other animals change the way they perceive the world due to experience. This process has been labeled as perceptual learning, and implies that adult nervous systems can adaptively modify the way in which they process sensory stimulation. However, the mechanisms by which the brain modifies this capacity have not been sufficiently analyzed. METHODOLOGY/PRINCIPAL FINDINGS: We studied the neural mechanisms of human perceptual learning by combining electroencephalographic (EEG) recordings of brain activity and the assessment of psychophysical performance during training in a visual search task. All participants improved their perceptual performance as reflected by an increase in sensitivity (d') and a decrease in reaction time. The EEG signal was acquired throughout the entire experiment revealing amplitude increments, specific and unspecific to the trained stimulus, in event-related potential (ERP) components N2pc and P3 respectively. P3 unspecific modification can be related to context or task-based learning, while N2pc may be reflecting a more specific attentional-related boosting of target detection. Moreover, bell and U-shaped profiles of oscillatory brain activity in gamma (30-60 Hz) and alpha (8-14 Hz) frequency bands may suggest the existence of two phases for learning acquisition, which can be understood as distinctive optimization mechanisms in stimulus processing. CONCLUSIONS/SIGNIFICANCE: We conclude that there are reorganizations in several neural processes that contribute differently to perceptual learning in a visual search task. We propose an integrative model of neural activity reorganization, whereby perceptual learning takes place as a two-stage phenomenon including perceptual, attentional and contextual processes.
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Fenômenos Eletrofisiológicos , Aprendizagem/fisiologia , Fenômenos Fisiológicos do Sistema Nervoso , Percepção/fisiologia , Adulto , Eletrodos , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Modelos Neurológicos , Estimulação Luminosa , Análise e Desempenho de Tarefas , Fatores de Tempo , Adulto JovemRESUMO
Objetivo: Determinar el perfil epidemiológico de los donadores de dientes humanos extraídos en establecimientos de salud pública, durante el año 2019. Metodología: Se realizó un estudio de tipo observacional, descriptivo y transversal de 224 donadores de dientes humanos entre 7 a 71 o más años que acudieron a las UCSF de Chalchuapa, Planes de Renderos, Cuscatancingo, Vía Mariona y San Lorenzo. Fueron caracterizados según indicadores sociales, clínicos bucales e historia médica del donador, causas de extracción y características físicas de los dientes extraídos. La recolección de datos se realizó con cédulas de entrevista y guías de observación. Se realizaron 250 extracciones. Resultados: El sexo prevalente es el femenino con 68.75%, siendo la zona urbana más afectada con el 66.97% y el grupo etario de 21 a 30 años con 23.21%, el 14.73% presentó hipertensión arterial. Según los indicadores clínicos bucales, el 10.27% mostró bruxismo, siendo la caries dental la enfermedad más prevalente con un 91.96%, observando un nivel ISHO óptimo de 58.48%. La principal causa de extracción fue la caries dental con 67.20%, el diente extraído con mayor frecuencia fue el 4-6(FDI). Entre las características de la corona, el 64.4% presentaron caries cavitadas > 2 mm. Respecto a la raíz el 94.40% poseen raíz completa y el 44.40% 1 raíz. Conclusión: La caries dental es la principal causa de extracción afectando más a las mujeres de 21 a 30 años que residen en el área urbana, siendo el diente 4- 6 el más afectado.
Objective: To determine the epidemiological profile of donors of human teeth extracted in public health facilities during the year of 2019. Methods: An observational, descriptive, and transversal study of 224 donors of human teeth 7 to 71 years old or more who attended the UCSF of Chalchuapa, Planes de Renderos, Cuscatancingo, Via Mariona, and San Lorenzo. The participants were characterized according to social and oral clinical indicators, medical history of the donor, causes of extraction, and physical characteristics of the extracted teeth. Data collection was done with interview cards and observation guides. A total of 250 extractions were performed. Results: The prevalent sex is female with 68.75%, being the urban area the most affected with 66.97% and the age group from 21 to 30 years old with 23.21%, 14.73% of participants presented arterial hypertension. According to oral clinical indicators, 10.27% of participants showed bruxism, being dental cavities the most prevalent disease with 91.96%, observing an optimal ISHO level of 58.48%. The main cause of extraction was dental cavities with 67.20%, the 4-6 (FDI) was the most frequently extracted tooth. Among the characteristics of the crown, 64.4% presented cavitated cavities > 2 mm. In regard to the root, 94.40% had complete root and 44.40% had one root. Conclusions: Dental cavities are the main cause of extraction, affecting mainly women from 21 to 30 years old living in urban areas, being tooth 4-6 the most affected.
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Perfil de Saúde , Doadores de Tecidos , Extração Dentária , EpidemiologiaRESUMO
Presentamos una nueva sección en la Revista Médica Vozandes, cuyo objetivo es desenmascarar algunos de los "mitos médicos" que se presentan con frecuencia en nuestra práctica clínica. conceptos e ideas rodeados de un aura de verdad que han sido develados como no verdaderos por la investigación biomédica. además es una cordial invitación a nuestros lectores para enviar sus propios artículos sobre mitología médica.
We present a new section in the Vozandes Medical Magazine, whose objective is to unmask some of the "medical myths" that are frequently presented in our clinical practice. concepts and ideas surrounded by an aura of truth that have been revealed as not true by biomedical research. It is also a cordial Invitation to our readers to send their own articles on medical mythology.
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Humanos , Medicina Baseada em Evidências , Prática Clínica Baseada em Evidências , Mitologia , Artigo de Revista , Pesquisa BiomédicaRESUMO
En este trabajo se describen las condiciones de salud en Ecuador y, con mayor detalle, las características del sistema ecuatoriano de salud, incluyendo su estructura y cobertura, sus fuentes de financiamiento, los recursos físicos, materiales y humanos de los que dispone, las tareas de rectoría que desarrolla el Ministerio de Salud Pública, la generación de información en salud, las tareas de investigación, y la participación de los ciudadanos en la operación y evaluación del sistema. También se discuten las innovaciones más recientes que se han implantado en el sistema ecuatoriano de salud dentro de las que destaca la incorporación de un capítulo específico sobre salud a la nueva Constitución que reconoce a la protección de la salud como un derecho humano y la construcción de la Red Pública Integral de Salud.
This paper describes the health conditions in Ecuador and, in more detail, the characteristics of the Ecuadorian health system, including its structure and coverage, its financial sources, the physical, material and human resources available, and the stewardship activities developed by the Ministry of Public Health. It also describes the structure and content of its health information system, and the participation of citizens in the operation and evaluation of the health system. The paper ends with a discussion of the most recent policy innovations implemented in the Ecuadorian system, including the incorporation of a chapter on health into the new Constitution which recognizes the protection of health as a human right, and the construction of the Comprehensive Public Health Network.