RESUMO

In this work, we propose a novel method for yttrium determination by microwave-induced optical emission spectrometry (MIP OES). It is based on the ultrasound-assisted extraction of yttrium with a diluted HNO3 solution and was applied to yttrium determination in phosphorus powder from fluorescent lamps. The method was optimized employing a multivariate strategy, based on a Box-Behnken design, taking into account three experimental factors: mass of the sample (25 to 75 mg), sonication time (15 to 165 min) and HNO3 concentration in the extractant solution (2.0 to 6.0 mol L-1). According to the data obtained in the optimization process, only the sonication time and the HNO3 concentration had an influence on the extraction of yttrium from the samples. The data also indicated that yttrium must be strongly linked to the matrix, since its quantitative extraction was only possible when using the maximum values of the two factors. Therefore, under optimized conditions, we could quantitatively extract yttrium from 75 mg of sample using a 6 mol per L HNO3 solution and a sonication time of 165 min. The limits of detection and quantification for the method were 0.4 and 1.2 µg g-1, respectively, and the intermediary precision (three days) was 14%. The concentration of Y in the analyzed samples varied from 5.37 ± 1.82 to 298 ± 31 µg g-1, and recoveries of 91.0 ± 34.6 and 106 ± 23% were obtained in comparison to total digestion. The results obtained by the proposed method were not statistically different (at the 95% confidence level) from those obtained after the total digestion of the samples when applying the Student's t-test.

RESUMO

Data collection, curation, and cleaning constitute a crucial phase in Machine Learning (ML) projects. In biomedical ML, it is often desirable to leverage multiple datasets to increase sample size and diversity, but this poses unique challenges, which arise from heterogeneity in study design, data descriptors, file system organization, and metadata. In this study, we present an approach to the integration of multiple brain MRI datasets with a focus on homogenization of their organization and preprocessing for ML. We use our own fusion example (approximately 84,000 images from 54,000 subjects, 12 studies, and 88 individual scanners) to illustrate and discuss the issues faced by study fusion efforts, and we examine key decisions necessary during dataset homogenization, presenting in detail a database structure flexible enough to accommodate multiple observational MRI datasets. We believe our approach can provide a basis for future similarly-minded biomedical ML projects.

RESUMO

A spatial survival analysis was performed to identify some of the factors that influence the survival of patients with COVID-19 in the states of Guerrero, México, and Chihuahua. The data that we analyzed correspond to the period from 28 February 2020 to 24 November 2021. A Cox proportional hazards frailty model and a Cox proportional hazards model were fitted. For both models, the estimation of the parameters was carried out using the Bayesian approach. According to the DIC, WAIC, and LPML criteria, the spatial model was better. The analysis showed that the spatial effect influences the survival times of patients with COVID-19. The spatial survival analysis also revealed that age, gender, and the presence of comorbidities, which vary between states, and the development of pneumonia increase the risk of death from COVID-19.

RESUMO

Wastewater-based epidemiology has been described as a valuable tool for monitoring the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a community. However, there is no consensus on the best concentration method to allow reliable detection of SARS-CoV-2 in this matrix, considering different laboratory facilities. This study compares two viral concentration methods, ultracentrifugation (ULT) and skimmed-milk flocculation (SMF), for detecting SARS-CoV-2 in wastewater samples. The analytical sensitivity (limits of detection and quantification [LoD/LoQ]) of both methods was evaluated using a bovine respiratory syncytial virus (BRSV) as a surrogate. Three different approaches were conducted to establish LoD of each method based on the assays on the standard curve (ALoDsc), on the dilution of internal control (ALoDiC), and the processing steps (PLoD). For PLoD, ULT method had the lowest value (1.86 × 103 genome copy/microliter [GC/µL]) when compared to the SMF method (1.26 × 107 GC/µL). The LoQ determination showed a mean value of 1.55 × 105 GC/µL and 3.56 × 108 GC/µL to ULT and SMF, respectively. The detection of SARSCoV-2 in naturally contaminated wastewater revealed 100% (12/12) and 25% (3/12) of detection using ULT and SMF with quantification ranging from 5.2 to 7.2 log10 genome copy/liter (GC/L) and 5.06 to 5.46 log10 GC/L, respectively. The detection success rate of BRSV used as an internal control process was 100% (12/12) for ULT and 67% (8/12) for SMF, with an efficiency recovery rate ranging from 12 to 38% and 0.1 to 5%, respectively. Our data consolidates the importance of assessing the methods used; however, further analysis should be carried out to improve low-cost concentration methodologies, essential for use in low-income and developing countries.

Assuntos

RESUMO

Central nervous system tumors, especially astrocytomas, are the solid neoplasms with the highest incidence and mortality rates in childhood. The diagnosis is based on histopathological characteristics, but molecular methods have been increasingly used. Translationally controlled tumor protein (TCTP) protein, encoded by the tumor protein, translationally controlled 1 (TPT1) gene, is a multifunctional protein with an important physiological role in the cell cycle. Expression of this protein has been associated with several neoplasms, including astrocytomas in adults. However, the role of this protein in pediatric astrocytomas is largely unknown. We aim to evaluate in cases of pediatric astrocytomas, the frequency of polymorphisms in the TPT1 gene and other genes associated with its molecular pathways, such as MTOR, MDM2, TP53, and CDKN1A, correlating it with protein expression and clinical variables, in formalin-fixed, paraffin-embedded (FFPE) samples. These samples were submitted to genotyping and immunohistochemistry analyses. The most revealing results refer to the MDM2 gene, rs117039649 [G/C], in which C polymorphic allele was observed only in the glioblastomas (p = .028). The CDKN1A gene, rs3176334 [T/C] presented a homozygous polymorphic genotype only in high-grade astrocytomas, when infiltrating tumors were compared (p = .039). The immunohistochemical expression of cytoplasmic MDM2 correlated with better survival rates in patients with glioblastoma (p = .018). The presence of polymorphisms in the MDM2 and CDKN1A genes, as well as a specific correlation between MDM2 expression, suggests a likely association with risk in pediatric astrocytomas. This study sought the probable role involved in the TCTP pathway, and associated proteins, in the tumorigenesis of pediatric astrocytomas, and some could have potential impact as prognostic markers in these patients.

Assuntos

RESUMO

Plants adjust their complex molecular, biochemical, and metabolic processes to overcome salt stress. Here, we investigated the proteomic and epigenetic alterations involved in the morphophysiological responses of Pfaffia glomerata, a medicinal plant, to salt stress and the demethylating agent 5-azacytidine (5-azaC). Moreover, we investigated how these changes affected the biosynthesis of 20-hydroxyecdysone (20-E), a pharmacologically important specialized metabolite. Plants were cultivated in vitro for 40 days in Murashige and Skoog medium supplemented with NaCl (50 mM), 5-azaC (25 µM), and NaCl + 5-azaC. Compared with the control (medium only), the treatments reduced growth, photosynthetic rates, and photosynthetic pigment content, with increase in sucrose, total amino acids, and proline contents, but a reduction in starch and protein. Comparative proteomic analysis revealed 282 common differentially accumulated proteins involved in 87 metabolic pathways, most of them related to amino acid and carbohydrate metabolism, and specialized metabolism. 5-azaC and NaCl + 5-azaC lowered global DNA methylation levels and 20-E content, suggesting that 20-E biosynthesis may be regulated by epigenetic mechanisms. Moreover, downregulation of a key protein in jasmonate biosynthesis indicates the fundamental role of this hormone in the 20-E biosynthesis. Taken together, our results highlight possible regulatory proteins and epigenetic changes related to salt stress tolerance and 20-E biosynthesis in P. glomerata, paving the way for future studies of the mechanisms involved in this regulation.

Assuntos

RESUMO

Echocardiography is commonly used in veterinary clinical practice for many species but is not as easily applied in non-sedated marine mammals. Additionally, Doppler echocardiography provides further information on hemodynamics, estimation of cardiac output, characterization of flow patterns, and diastolic function. However, its applications in marine mammals have not been as widely explored either. The present report aimed to characterize the left ventricle structure and function of the Southern Sea Lion (Otaria flavescens) through a Doppler echocardiography study. Data were obtained from a healthy animal trained for different veterinary examination routines. This communication constitutes the first report of Doppler echocardiography with stroke volume, and cardiac output measurement in pinnipeds, and the first report of measurement of myocardial performance index in aquatic mammals. This data brought initial information about in vivo structure and function of the heart of the Southern Sea Lion that can be safely and effectively evaluated with the use of transthoracic Doppler echocardiography. Our data have both clinical and research implications for future studies evaluating diseases of the cardiopulmonary system in pinnipeds, and cardiovascular physiology investigation in diving mammals.

Assuntos

RESUMO

OBJECTIVE: Evaluate the effect of thickness of high-translucency (HT) CAD/CAM materials on irradiance and beam profile from a blue light-emitting diode light-curing unit (LCU) and on the degree of conversion (DC) and maximum polymerization rate (Rpmax ) of a light-cured resin cement (LCC). MATERIAL AND METHODS: The direct output from the LCU, the light transmission and irradiance ratio (IR) through one conventional composite and nine HT CAD/CAM materials (0.5, 1.0, 1.5, or 2.0-mm thick; n = 5) were measured with a integrating sphere coupled to a spectrometer. The light beam was assessed with a beam profiler camera. The DC at 600 s and the Rpmax of one LCC was determined using a Fourier transform infrared spectrometer (n = 5). Data were analyzed by ANOVA followed by Tukey's tests, and Dunnett's test was also used for irradiance data (α = 0.05). RESULTS: A significant decrease in irradiance through all materials occurred as thickness increased. Thin CAD/CAM materials improved light homogeneity, which decreased with the increase in thickness. The DC of the LCC directly exposed to light was the same as when exposed to 45%, 25%, 15%, or 5% IRs. Rpmax decreased with the decrease in IR. CONCLUSIONS: Although the HT CAD/CAM materials reduced the irradiance from the LCU, minor effects were observed in the LCC's DC. CLINICAL SIGNIFICANCE: Despite the light attenuation of blue light through different CAD/CAM materials that were up to 2-mm thick, the degree of conversion of one brand of light-cured resin cement was clinically acceptable when the LCU was used for 30 s.

Assuntos

Assuntos

RESUMO

Background: Although several epidemiological studies of asthma have been carried out in Ecuador in the last two decades, none of these has estimated the prevalence of asthma in adult populations. Objective: To estimate the prevalence of asthma symptoms in adults in the city of Quito and to identify possible associated factors. Methods: A cross-sectional study was conducted on subjects older than 18 years residing in the Metropolitan District of Quito. The Global Asthma Network (GAN) questionnaire was applied to collect information on asthma symptoms and sociodemographic and lifestyle data. Bivariate and multivariate analyses with logistic regression were used to identify asthma-related factors. Results: 2,476 subjects answered the questionnaire (80.9% women, mean age 40 years). The prevalence of wheezing in the last 12 months, asthma ever, and asthma diagnosed by a doctor were 6.3%, 1.9% and 1.6%, respectively. The prevalence of rhinitis ever and eczema ever was 13.7% and 5.5%. The presence of mould at home (OR: 2.13; 95% CI: 1.48 -3.06; p <0.001), cat at home (OR: 1.06; 95% CI: 1.06 -2.13; p <0.022) and rhinitis at some time (OR: 3.65; 95% CI: 2.53 - 5.29; p <0.022) were associated with the presence of wheezing in the last 12 months. Conclusions: Our study shows that, compared to other cities in Latin America, the prevalence of asthma in adults in Quito is relatively low. Along with the presence of rhinitis, factors related to housing quality are closely linked to the occurrence of asthma in adult populations.

Antecedentes: Aunque en el Ecuador se han realizado varios estudios epidemiológicos de asma en las dos últimas décadas, ninguno de estos ha estimado la prevalencia de asma en poblaciones adultas. Objetivo: Estimar la prevalencia de síntomas de asma en adultos en Quito e identificar posibles factores asociados. Métodos: Se realizó un estudio transversal en sujetos mayores a 18 años residentes en la ciudad de Quito-Ecuador. Se aplicó el cuestionario Global Asthma Network para recolectar información sobre síntomas de asma y datos sociodemográficas y de estilo de vida. Para la identificación de factores asociados con asma se utilizó análisis bivariados y multivariados con regresión logística. Resultados: Un total de 2,476 sujetos respondieron el cuestionario (80.9% mujeres, edad media 40 años). La prevalencia de sibilancias en los últimos 12 meses, asma alguna vez y asma diagnosticado por un médico fue de 6.3%; 1.9% y 1.6%, respectivamente. La prevalencia de rinitis y eczema alguna vez fue de 13.7% y 5.5%. La presencia de moho en el hogar (OR: 2.13; 95% IC: 1.48-3.06; p <0.001), gato en casa (OR: 1.06; 95% IC: 1.06-2.13; p <0.022) y rinitis alguna vez (OR: 3.65; 95% IC: 2.53-5.29; p <0.022) estaban asociados con la presencia de sibilancias en los últimos 12 meses. Conclusiones: Nuestro estudio muestra que, en comparación con otras ciudades de América Latina, la prevalencia de asma en adultos en Quito es relativamente baja. Junto con la presencia de rinitis, factores relacionados con la calidad de la vivienda están estrechamente ligados con la ocurrencia de asma en poblaciones adultas.

Assuntos