Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 57
Filtrar
1.
Entropy (Basel) ; 26(3)2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38539689

RESUMO

Since financial assets on stock exchanges were created, investors have sought to predict their future values. Currently, cryptocurrencies are also seen as assets. Machine learning is increasingly adopted to assist and automate investments. The main objective of this paper is to make daily predictions about the movement direction of financial time series through classification models, financial time series preprocessing methods, and feature selection with genetic algorithms. The target time series are Bitcoin, Ibovespa, and Vale. The methodology of this paper includes the following steps: collecting time series of financial assets; data preprocessing; feature selection with genetic algorithms; and the training and testing of machine learning models. The results were obtained by evaluating the models with the area under the ROC curve metric. For the best prediction models for Bitcoin, Ibovespa, and Vale, values of 0.61, 0.62, and 0.58 were obtained, respectively. In conclusion, the feature selection allowed the improvement of performance in most models, and the input series in the form of percentage variation obtained a good performance, although it was composed of fewer attributes in relation to the other sets tested.

2.
Sci Rep ; 13(1): 18355, 2023 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-37884637

RESUMO

Serum 25-hydroxyvitamin D concentrations deficiency is a growing health problem that affects a significant part of the world's population, with particularly negative consequences in children and older adults. Public health has prioritized healthy aging; thus, an investigation of the social determinants related to deficient and insufficient Serum 25-hydroxyvitamin D concentrations in older adults is needed to contribute to the implementation of comprehensive social programs focused on addressing those conditions adversely affecting the health of this group. This study was conducted using a sample of older adults (age ≥ 65 years, n = 1283) from the National Health Survey (NHS 2016-2017). The Average Marginal Effects of the social determinants of Serum 25-hydroxyvitamin D concentrations deficiency in older adults were predicted using a probit model in which the outcome variable assumed two values (deficiency or not deficiency), taking as independent variables those reported in previous studies. The model showed an adequate goodness of fit, Count R2 = 0.65, and the independent variables explained between 11% (Cox-Snell) and 14% (Nagelkerke) of the variance of the outcome variable. The social determinants associated with a greater likelihood of Serum 25-hydroxyvitamin D concentrations deficiency are the following conditions: women, people of native origin, urban dwellers, shorter sunlight exposure, and greater geographical latitude. Implications are discussed, and limitations are considered. Promotion and prevention programs should preferentially target older adults in the southernmost regions who live in urban areas, with a special focus on women. Due to the country's characteristics (17°-57° south latitude), it is necessary to review in future research the three zones shown in this study as relevant social determinants for the older adults living in them to generate inputs in formulating public health policies. The authorities must define the cut-off points for considering the difference between the country's ranges of Serum 25-hydroxyvitamin D concentrations insufficiency and deficiency.


Assuntos
Determinantes Sociais da Saúde , Deficiência de Vitamina D , Vitamina D , Idoso , Feminino , Humanos , Calcifediol/sangue , Estações do Ano , Vitamina D/sangue , Deficiência de Vitamina D/epidemiologia
3.
Plants (Basel) ; 12(10)2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37653842

RESUMO

Background: Carotenoids, which are secondary metabolites derived from isoprenoids, play a crucial role in photo-protection and photosynthesis, and act as precursors for abscisic acid, a hormone that plays a significant role in plant abiotic stress responses. The biosynthesis of carotenoids in higher plants initiates with the production of phytoene from two geranylgeranyl pyrophosphate molecules. Phytoene synthase (PSY), an essential catalytic enzyme in the process, regulates this crucial step in the pathway. In Daucus carota L. (carrot), two PSY genes (DcPSY1 and DcPSY2) have been identified but only DcPSY2 expression is induced by ABA. Here we show that the ectopic expression of DcPSY2 in Nicotiana tabacum L. (tobacco) produces in L3 and L6 a significant increase in total carotenoids and chlorophyll a, and a significant increment in phytoene in the T1L6 line. Tobacco transgenic T1L3 and T1L6 lines subjected to chronic NaCl stress showed an increase of between 2 and 3- and 6-fold in survival rate relative to control lines, which correlates directly with an increase in the expression of endogenous carotenogenic and abiotic-related genes, and with ABA levels. Conclusions: These results provide evidence of the functionality of DcPSY2 in conferring salt stress tolerance in transgenic tobacco T1L3 and T1L6 lines.

4.
Sensors (Basel) ; 23(11)2023 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-37299922

RESUMO

Biometrics-based authentication has become the most well-established form of user recognition in systems that demand a certain level of security. For example, the most commonplace social activities stand out, such as access to the work environment or to one's own bank account. Among all biometrics, voice receives special attention due to factors such as ease of collection, the low cost of reading devices, and the high quantity of literature and software packages available for use. However, these biometrics may have the ability to represent the individual impaired by the phenomenon known as dysphonia, which consists of a change in the sound signal due to some disease that acts on the vocal apparatus. As a consequence, for example, a user with the flu may not be properly authenticated by the recognition system. Therefore, it is important that automatic voice dysphonia detection techniques be developed. In this work, we propose a new framework based on the representation of the voice signal by the multiple projection of cepstral coefficients to promote the detection of dysphonic alterations in the voice through machine learning techniques. Most of the best-known cepstral coefficient extraction techniques in the literature are mapped and analyzed separately and together with measures related to the fundamental frequency of the voice signal, and its representation capacity is evaluated on three classifiers. Finally, the experiments on a subset of the Saarbruecken Voice Database prove the effectiveness of the proposed material in detecting the presence of dysphonia in the voice.


Assuntos
Disfonia , Voz , Humanos , Disfonia/diagnóstico , Acústica da Fala , Qualidade da Voz , Medida da Produção da Fala/métodos
5.
Medwave ; 22(6)2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35917236

RESUMO

Introduction The COVID- 19 pandemic discontinued sexual and reproductive health care in Chile and the world. The national focus on hospital care led primary care teams to respond in natural and diverse ways. Understanding the factors involved in this process may improve future responses from the judgment of good practices. Therefore, this study aimed to identify and systematize sexual and reproductive health initiatives raised by primary care teams in response to the COVID- 19 pandemic in Chile. Methods We systematically evaluated initiatives and practices in sexual and reproductive health in prima-ry care between June 2020 and November 2021. This study was developed in three methodological phases: a review of documents, a collection of experiences through an electronic instrument sent to the 29 health services in Chile, and in-depth interviews. According to best practice criteria, mapping and characterizing the initiatives and critical discourse analysis of narratives and interviews were carried out. Results Forty-one initiatives from 19 health services were identified, mainly from the South Central macro zone and urban areas. In these areas, care was recognized. These practices were relevant, aligned with their objectives, rapidly implemented, and used novel strategies through new technologies. However, these initiatives had little intercultural relevance or evaluation. Perceived success was related to motivation, leadership, and institutional and community resilience. The adaptability of initiatives emerged as a new need and criterion of analysis. Conclusion The lessons learned from these initiatives invite us to consider health care teams' mental health, their relationship with the community, the use of new technologies, the evaluation of practices considering satisfaction, cross- cutting approaches, and their adaptability. In all, these aspects may improve primary care response in sexual and reproductive health to new crises.


Introducción La pandemia de COVID- 19 ha implicado la discontinuidad de atención en salud sexual y reproductiva en Chile y el mundo. El foco en la contención hospitalaria de la pandemia llevó a los equipos de atención primaria a responder de manera innata y diversa. Por lo tanto, el objetivo de este estudio fue identificar y sistematizar iniciativas de salud sexual y reproductiva planteadas por equipos de atención primaria en respuesta a la pandemia COVID- 19 en Chile, con el fin de comprender y aprender de los factores involucrados en esta, para mejorar futuras respuestas desde la lógica de buenas prácticas. Metodología Estudio de sistematización de iniciativas y prácticas en salud sexual y reproductiva en atención primaria, entre junio de 2020 y noviembre de 2021. Fue desarrollado en tres fases metodológicas: revisión de documentos, recolección de experiencias a través de instrumento electrónico enviado a los 29 servicios de salud de Chile y entrevistas de profundización. Se realizó un mapeo y caracterización de las iniciativas y análisis crítico de discurso de narrativas y entrevistas, según criterios de buenas prácticas. Resultados Se identificaron 41 iniciativas de 19 servicios de salud, principalmente de la Macro Zona Centro- sur, urbanas y de reorganización de atención. Fueron prácticas pertinentes, alineadas a sus objetivos, con procesos rápidos de implementación, estrategias innovadoras, alto uso de tecnologías con escasa pertinencia intercultural ni evaluación. El éxito percibido se relacionó con motivación, liderazgo, y resiliencia institucional y comunitaria. La adaptabilidad de las iniciativas emergió como una nueva necesidad y criterio. Conclusión Son importantes los aprendizajes emanados de las iniciativas que invitan a considerar la salud mental de los equipos, su relación con la comunidad, el uso de tecnologías, la evaluación de las prácticas considerando satisfacción, enfoques transversales y la adaptabilidad de estas, para mejorar la respuesta de atención primaria en salud sexual y reproductiva ante nuevas crisis.


Assuntos
COVID-19 , Chile , Humanos , Pandemias , Atenção Primária à Saúde , Saúde Reprodutiva
6.
Rev. chil. nutr ; 49(4)ago. 2022.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1449884

RESUMO

Actualmente, existe una necesidad en la industria alimentaria de buscar preservantes de origen natural que tengan una mejor aceptación por el consumidor. Una alternativa interesante que ha emergido en los últimos años es el uso de antimicrobianos naturales, los cuales además de ser efectivos en el control de microorganismos, son inocuos para la salud. La nisina es una bacteriocina producida por bacterias ácido lácticas que se utiliza actualmente como preservante en varios productos alimenticios. En Chile, el uso de la nisina como aditivo está restringido a quesos y cremas naturales o nata cuajada, pero existen otros alimentos que podrían beneficiarse del uso de este preservante, como es el caso de los aderezos tipo mayonesa vegetal. En el presente trabajo, se analiza de manera teórica, como el uso de nisina en estos aderezos impactaría el consumo máximo permitido para este aditivo en la población chilena. Para esto, se analizó cuál es el consumo teórico actual de nisina en Chile, y cómo este se vería afectado si se utilizara nisina como preservante en aderezos tipo mayonesa vegetal. Finalmente, los datos obtenidos se compararon con el valor de ingesta diaria admisible (IDA) para la nisina, evidenciándose que existe una ventana de oportunidad para el uso de nisina en otros productos alimenticios.


Currently, there is a need in the food industry for natural preservatives that have good consumers acceptance. Natural antimicrobials are a novel alternative, effective in controlling microbial growth, and safe to consume. Nisin is a bacteriocin produced by lactic acid bacteria that is currently used as a preservative in several food products. In Chile, nisin is regulated and restricted as an additive to cheeses and natural creams or curds. However, other food products could benefit from using nisin as a preservative, such as plant-based mayonnaise, where the consumer expects to find natural preservatives. In this review, we make a theoretical analysis of how adding nisin to plant-based mayonnaise would impact the daily intake of this additive in the Chilean population. Finally, we compare this data with the acceptable daily intake for nisin to conclude that there is an opportunity for using nisin as a preservative in plant-based mayonnaise without affecting consumers´ health.

7.
Medwave ; 22(6): e002555, jul.-2022.
Artigo em Inglês, Espanhol | LILACS | ID: biblio-1381419

RESUMO

Introducción La pandemia de COVID- 19 ha implicado la discontinuidad de atención en salud sexual y reproductiva en Chile y el mundo. El foco en la contención hospitalaria de la pandemia llevó a los equipos de atención primaria a responder de manera innata y diversa. Por lo tanto, el objetivo de este estudio fue identificar y sistematizar iniciativas de salud sexual y reproductiva planteadas por equipos de atención primaria en respuesta a la pandemia COVID- 19 en Chile, con el fin de comprender y aprender de los factores involucrados en esta, para mejorar futuras respuestas desde la lógica de buenas prácticas. Metodología Estudio de sistematización de iniciativas y prácticas en salud sexual y reproductiva en atención primaria, entre junio de 2020 y noviembre de 2021. Fue desarrollado en tres fases metodológicas: revisión de documentos, recolección de experiencias a través de instrumento electrónico enviado a los 29 servicios de salud de Chile y entrevistas de profundización. Se realizó un mapeo y caracterización de las iniciativas y análisis crítico de discurso de narrativas y entrevistas, según criterios de buenas prácticas. Resultados Se identificaron 41 iniciativas de 19 servicios de salud, principalmente de la Macro Zona Centro- sur, urbanas y de reorganización de atención. Fueron prácticas pertinentes, alineadas a sus objetivos, con procesos rápidos de implementación, estrategias innovadoras, alto uso de tecnologías con escasa pertinencia intercultural ni evaluación. El éxito percibido se relacionó con motivación, liderazgo, y resiliencia institucional y comunitaria. La adaptabilidad de las iniciativas emergió como una nueva necesidad y criterio. Conclusión Son importantes los aprendizajes emanados de las iniciativas que invitan a considerar la salud mental de los equipos, su relación con la comunidad, el uso de tecnologías, la evaluación de las prácticas considerando satisfacción, enfoques transversales y la adaptabilidad de estas, para mejorar la respuesta de atención primaria en salud sexual y reproductiva ante nuevas crisis.


Introducción La pandemia de COVID- 19 ha implicado la discontinuidad de atención en salud sexual y reproductiva en Chile y el mundo. El foco en la contención hospitalaria de la pandemia llevó a los equipos de atención primaria a responder de manera innata y diversa. Por lo tanto, el objetivo de este estudio fue identificar y sistematizar iniciativas de salud sexual y reproductiva planteadas por equipos de atención primaria en respuesta a la pandemia COVID- 19 en Chile, con el fin de comprender y aprender de los factores involucrados en esta, para mejorar futuras respuestas desde la lógica de buenas prácticas. Metodología Estudio de sistematización de iniciativas y prácticas en salud sexual y reproductiva en atención primaria, entre junio de 2020 y noviembre de 2021. Fue desarrollado en tres fases metodológicas: revisión de documentos, recolección de experiencias a través de instrumento electrónico enviado a los 29 servicios de salud de Chile y entrevistas de profundización. Se realizó un mapeo y caracterización de las iniciativas y análisis crítico de discurso de narrativas y entrevistas, según criterios de buenas prácticas. Resultados Se identificaron 41 iniciativas de 19 servicios de salud, principalmente de la Macro Zona Centro- sur, urbanas y de reorganización de atención. Fueron prácticas pertinentes, alineadas a sus objetivos, con procesos rápidos de implementación, estrategias innovadoras, alto uso de tecnologías con escasa pertinencia intercultural ni evaluación. El éxito percibido se relacionó con motivación, liderazgo, y resiliencia institucional y comunitaria. La adaptabilidad de las iniciativas emergió como una nueva necesidad y criterio. Conclusión Son importantes los aprendizajes emanados de las iniciativas que invitan a considerar la salud mental de los equipos, su relación con la comunidad, el uso de tecnologías, la evaluación de las prácticas considerando satisfacción, enfoques transversales y la adaptabilidad de estas, para mejorar la respuesta de atención primaria en salud sexual y reproductiva ante nuevas crisis.


Assuntos
Humanos , COVID-19 , Atenção Primária à Saúde , Chile , Pandemias , Saúde Reprodutiva
8.
Sensors (Basel) ; 22(12)2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35746343

RESUMO

Job Shop Scheduling is currently one of the most addressed planning and scheduling optimization problems in the field. Due to its complexity, as it belongs to the NP-Hard class of problems, meta-heuristics are one of the most commonly used approaches in its resolution, with Genetic Algorithms being one of the most effective methods in this category. However, it is well known that this meta-heuristic is affected by phenomena that worsen the quality of its population, such as premature convergence and population concentration in regions of local optima. To circumvent these difficulties, we propose, in this work, the use of a guidance operator responsible for modifying ill-adapted individuals using genetic material from well-adapted individuals. We also propose, in this paper, a new method of determining the genetic quality of individuals using genetic frequency analysis. Our method is evaluated over a wide range of modern GAs and considers two case studies defined by well-established JSSP benchmarks in the literature. The results show that the use of the proposed operator assists in managing individuals with poor fitness values, which improves the population quality of the algorithms and, consequently, leads to obtaining better results in the solution of JSSP instances. Finally, the use of the proposed operator in the most elaborate GA-like method in the literature was able to reduce its mean relative error from 1.395% to 0.755%, representing an improvement of 45.88%.


Assuntos
Algoritmos , Heurística , Humanos
9.
Plants (Basel) ; 11(3)2022 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-35161399

RESUMO

In this work, we have investigated the accumulation of ryanoids in different plant parts (leaves, stems and roots) of aeroponically grown Persea indica cloned trees (one-year-old cloned individuals) and a selected mature, wild tree. We tested the insect antifeedant (against Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi) and nematicidal (against Meloidogyne javanica) effects of ethanolic extracts from these different plant parts. The HPLC-MS analysis of P. indica extracts showed that mature tree (wild) leaves had two times more chemical diversity than stems. Aeroponic plants showed fewer differences in chemical diversity between leaves and stems, with the lowest diversity found in the roots. Ryanodane epiryanodol (1) was present in all the plant parts, with the mature stems (wild) containing the highest amount. The aeroponic stems also accumulated ryanoids including 1, cinnzeylanol (2) and cinnzeylanone (4). The insect Spodoptera littoralis was strongly affected by the stem extracts, while leaf extracts were moderately active. Based on predicted vs. real antifeedant values, we concluded that the ryanoid content (1 or a combination of 2, 4 and 1) explained the antifeedant effects of the stem extracts, while additional components contributed to the activity of the leaf extracts. Therefore, careful individual selection of P. indica seedlings should be carried out prior to proceeding with aeroponic cultivation in order to obtain ryanodane-rich stem or leaf extracts with strong antifeedant effects on S. littoralis.

10.
Physiol Biochem Zool ; 95(1): 66-81, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34875208

RESUMO

AbstractDuring the past 60 years, mammalian hibernation (i.e., seasonal torpor) has been interpreted as a physiological adaptation for energy economy. However, direct field comparisons of energy expenditure and torpor use in hibernating and active free-ranging animals are scarce. Here, we followed the complete hibernation cycle of a fat-storing hibernator, the marsupial Dromiciops gliroides, in its natural habitat. Using replicated mesocosms, we experimentally manipulated energy availability and measured torpor use, hibernacula use, and social clustering throughout the entire hibernation season. Also, we measured energy flow using daily food intake, daily energy expenditure (DEE), and basal metabolic rate (BMR) in winter. We hypothesized that when facing chronic caloric restriction (CCR), a hibernator should maximize torpor frequency to compensate for the energetic deficit, compared with individuals fed ad lib. (controls). However, being torpid at low temperatures could increase other burdens (e.g., cost of rewarming, freezing risks). Our results revealed that CCR animals, compared with control animals, did not promote heat conservation strategies (i.e., clustering and hibernacula use). Instead, they gradually increased torpor frequency and reduced DEE and, as a consequence, recovered weight at the end of the season. Also, CCR animals consumed food at a rate of 50.8 kJ d-1, whereas control animals consumed food at a rate of 98.4 kJ d-1. Similarly, the DEE of CCR animals in winter was 47.3±5.64 kJ d-1, which was significantly lower than control animals (DEE=88.0±5.84 kJ d-1). However, BMR and lean mass of CCR and control animals did not vary significantly, suggesting that animals maintained full metabolic capacities. This study shows that the use of torpor can be modulated depending on energy supply, thus optimizing energy budgeting. This plasticity in the use of heterothermy as an energy-saving strategy would explain the occurrence of this marsupial in a broad latitudinal and altitudinal range. Overall, this study suggests that hibernation is a powerful strategy to modulate energy expenditure in mammals from temperate regions.


Assuntos
Hibernação , Marsupiais , Torpor , Animais , Metabolismo Basal , Restrição Calórica , Metabolismo Energético , Estações do Ano
11.
Nanoscale ; 13(42): 17807-17821, 2021 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-34668502

RESUMO

Gold nanoparticles (GNPs) are an attractive nanomaterial for potential applications in therapy and diagnostics due to their capability to direct toward specific sites in the organism. However, when exposed to plasma, GNPs can interact with different biomolecules that form a dynamic nano-bio interface called a "protein corona" (PC). Remarkably, the PC could affect multiple biological processes, such as cell targeting and uptake, cytotoxicity, and nanoparticle (NP) clearance. The interaction of nanomaterials with plasmatic proteins has been widely studied under bulk conditions, however, under dynamic conditions, it has just recently been explored. Thus, to mimic a dynamic natural environment found in arteries and veins, microfluidic devices were used. In this work, gold nanorods (GNRs) were synthesized and conjugated with polyethylene glycol (PEG) to reduce their interaction with plasma proteins and increase their biocompatibility. Then, GNRs were functionalized with folic acid, a targeting ligand typically used to recognize tumor cells. The resulting nanosystem was exposed to fibrinogen (FB) to study the development and biological impact of PC formation through two strategies: bulk and laminar flow conditions. The obtained nanosystems were characterized by absorption spectrophotometry, DLS, laser Doppler microelectrophoresis, neutron activation analysis, circular dichroism spectroscopy and TEM. Finally, cell viability and cellular uptake assays were performed to study the influence of the PC on the cell viability and delivery of nanosystems.


Assuntos
Nanopartículas Metálicas , Nanotubos , Neoplasias , Adsorção , Fibrinogênio , Ácido Fólico , Ouro , Nanopartículas Metálicas/toxicidade , Microfluídica , Neoplasias/tratamento farmacológico , Polietilenoglicóis
12.
Sensors (Basel) ; 21(13)2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34208996

RESUMO

A large number of stroke survivors suffer from a significant decrease in upper extremity (UE) function, requiring rehabilitation therapy to boost recovery of UE motion. Assessing the efficacy of treatment strategies is a challenging problem in this context, and is typically accomplished by observing the performance of patients during their execution of daily activities. A more detailed assessment of UE impairment can be undertaken with a clinical bedside test, the UE Fugl-Meyer Assessment, but it fails to examine compensatory movements of functioning body segments that are used to bypass impairment. In this work, we use a graph learning method to build a visualization tool tailored to support the analysis of stroke patients. Called NE-Motion, or Network Environment for Motion Capture Data Analysis, the proposed analytic tool handles a set of time series captured by motion sensors worn by patients so as to enable visual analytic resources to identify abnormalities in movement patterns. Developed in close collaboration with domain experts, NE-Motion is capable of uncovering important phenomena, such as compensation while revealing differences between stroke patients and healthy individuals. The effectiveness of NE-Motion is shown in two case studies designed to analyze particular patients and to compare groups of subjects.


Assuntos
Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Humanos , Movimento , Recuperação de Função Fisiológica , Extremidade Superior
13.
Rev. nefrol. diál. traspl ; 41(2): 11-20, jun. 2021. graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1377128

RESUMO

RESUMEN Antecedentes: La prueba de lanzadera incremental ha sido empleada para determinar la capacidad física en pacientes con enfermedad renal crónica. Sin embargo, su aplicabilidad y reproducibilidad ha sido poco estudiada en pacientes bajo tratamiento de hemodiálisis. El objetivo de este estudio fue evaluar el rendimiento y reproducibilidad de la prueba de lanzadera incremental en pacientes con enfermedad renal crónica en hemodiálisis. Material y métodos: Se incluyeron pacientes con enfermedad renal crónica en diálisis y sujetos sin enfermedad renal crónica. Cada individuo realizó dos pruebas de lanzadera incremental con un intervalo de 30 minutos. Se registró la distancia recorrida, velocidad máxima, frecuencia cardiaca y el esfuerzo percibido. La reproducibilidad se analizó mediante el cálculo del coeficiente de correlación intraclase y el error estándar de la media. Mediante el método de Bland-Altman, se calculó la discordancia de la distancia recorrida y la frecuencia cardiaca pico. Además, se calculó el cambio mínimo detectable para todos los parámetros de la prueba de lanzadera incremental. Un valor de p=<0,05 se consideró significativo. Resultados: 68 sujetos entraron al estudio (34 pacientes con enfermedad renal crónica y 34 sujetos en el grupo control). Los pacientes con enfermedad renal crónica caminaron una menor distancia recorrida respecto al grupo control (-40%; p=<0,0001). En ambos grupos, se encontró una excelente confiabilidad test/retest en todas las medidas de resultado (cálculo del coeficiente de correlación intraclase >0,80). Los registros del error estándar de medición y cambio mínimo detectable para la distancia recorrida fueron de 26,0 m y 72,1 m, respectivamente. El método de Bland-Altman para la distancia recorrida mostró una diferencia media de -0,9 m con límites de concordancia entre 65,5 y -63,7 m. Conclusión: Los pacientes con enfermedad renal crónica en hemodiálisis presentan un menor rendimiento durante la prueba de lanzadera incremental comparado con individuos sin enfermedad renal crónica. Las medidas de resultado de la prueba de lanzadera incremental presentan una alta reproducibilidad test/retest a corto plazo en este grupo de pacientes.


ABSTRACT Introduction: The Incremental Shuttle Walk Test has been used to determine physical capacity in patients with chronic kidney disease. However, its applicability and reproducibility have seldom been studied in hemodialysis patients. The objective of this study was to evaluate the performance and reproducibility of the incremental shuttle walk test in patients with chronic kidney disease on hemodialysis. Methods: Patients with chronic kidney disease on dialysis and subjects without chronic kidney disease were included. Each individual performed two Incremental Shuttle Walk Test with an interval of 30 minutes. We recorded the distance traveled, maximum speed, heart rate and perceived effort. Reproducibility was analyzed by calculating the intraclass correlation coefficient and the standard error of the mean. Using the Bland-Altman analysis, we calculated the discrepancy of the distance traveled and the peak heart rate. The minimum detectable change was also calculated for all parameters of the incremental shuttle walk test. A value of p=<0.05 was considered significant. Results: 68 subjects entered the study (34 were patients with chronic kidney disease, and 34 subjects constituted the control group). Patients with chronic kidney disease walked a shorter distance than those in the control group (-40%; p=<0.0001). In both groups, excellent test-retest reliability was found in all outcome measurements (intraclass correlation coefficient calculation >0.80). The standard error of measurement and the minimum detectable change for the distance traveled were 26.0 m and 72.1 m, respectively. The Bland-Altman analysis for the distance traveled showed a mean difference of -0.9 m with limits of agreement between 65.5 and -63.7 m. Conclusion: Patients with chronic kidney disease on hemodialysis show lower performance during the incremental shuttle walk test, compared to individuals without chronic kidney disease. The outcome measurements of the Incremental Shuttle Walk Test show high test-retest reproducibility in the short run in this group of patients.

14.
Rev. chil. cardiol ; 40(1): 59-64, abr. 2021. ilus
Artigo em Espanhol | LILACS | ID: biblio-1388079

RESUMO

Resumen: La disección coronaria espontánea ha surgido como una causa interesante y poco reconocida de síndrome coronario agudo no aterosclerótico. Ocurre más frecuentemente en mujeres jóvenes, donde de forma importante puede asociarse a anomalías arteriales no coronarias. La clave para un tratamiento oportuno es el diagnóstico precoz que impida su evolución a cuadros más severos. Se presenta el caso de una mujer de 36 años con un síndrome coronario agudo secundario a una disección coronaria espontánea bi-arterial que evolucionó de forma grave a una insuficiencia cardíaca aguda. El objetivo es informar un cuadro poco usual y proporcionar evidencia que respalde el cómo debe enfrentarse.


Abstract: Spontaneous coronary dissection is an important cause of acute non-atherosclerotic coronary syndrome. It occurs more frequently in young women, often without significantly associated coronary arterial anomalies. Early diagnosis is a key to prompt treatment, in order to prevent severe complications. We report the case of a 36-year-old woman with an acute coronary syndrome secondary to spontaneous bi-arterial coronary dissection progressing to severe acute heart failure. A discussion of the management of this condition is included.


Assuntos
Humanos , Feminino , Adulto , Doenças Vasculares/cirurgia , Doenças Vasculares/complicações , Anomalias dos Vasos Coronários/cirurgia , Anomalias dos Vasos Coronários/complicações , Infarto do Miocárdio/etiologia , Doenças Vasculares/diagnóstico por imagem , Stents , Anomalias dos Vasos Coronários/diagnóstico por imagem , Intervenção Coronária Percutânea
15.
Front Plant Sci ; 12: 635491, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33732277

RESUMO

Deschampsia antarctica Desv, is the most successful colonizing species of a cold continent. In recent years due to climate change, the frequency of heat waves has increased in Antarctica, registering anomalous high temperatures during the summer of 2020. However, the populations of D. antarctica are responding positively to these events, increasing in number and size throughout the Antarctic Peninsula. In this work, the physiological and biochemical responses of D. antarctica plants grown in vitro (15 ± 1°C) and plants subjected to two heat shock treatments (23 and 35°C) were evaluated. The results obtained show that D. antarctica grown in vitro is capable of tolerating heat shock treatments; without showing visible damage to its morphology, or changes in its oxidative state and photosynthetic performance. These tolerance responses are primarily mediated by the efficient role of enzymatic and non-enzymatic antioxidant systems that maintain redox balance at higher temperatures. It is postulated that these mechanisms also operate in plants under natural conditions when exposed to environmental stresses.

16.
Sensors (Basel) ; 20(18)2020 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-32971959

RESUMO

It is not uncommon for today's problems to fall within the scope of the well-known class of NP-Hard problems. These problems generally do not have an analytical solution, and it is necessary to use meta-heuristics to solve them. The Job Shop Scheduling Problem (JSSP) is one of these problems, and for its solution, techniques based on Genetic Algorithm (GA) form the most common approach used in the literature. However, GAs are easily compromised by premature convergence and can be trapped in a local optima. To address these issues, researchers have been developing new methodologies based on local search schemes and improvements to standard mutation and crossover operators. In this work, we propose a new GA within this line of research. In detail, we generalize the concept of a massive local search operator; we improved the use of a local search strategy in the traditional mutation operator; and we developed a new multi-crossover operator. In this way, all operators of the proposed algorithm have local search functionality beyond their original inspirations and characteristics. Our method is evaluated in three different case studies, comprising 58 instances of literature, which prove the effectiveness of our approach compared to traditional JSSP solution methods.

17.
Biol Res ; 52(1): 46, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31434576

RESUMO

BACKGROUND: One of the most extreme environments on our planet is the Maritime Antarctic territory, due to its low-water availability, which restricts the development of plants. Sanionia uncinata Hedw. (Amblystegiaceae), the main colonizer of the Maritime Antarctic, has effective mechanisms to tolerate this environment. It has been described that the tolerance to desiccation is mediated by the hormone abscisic acid (ABA), antioxidants systems, accumulation of compatible solutes and proteins of the late embryogenesis abundant (LEA). However, to date, these mechanisms have not been described in S. uncinata. Therefore, in this work, we postulate that the tolerance to desiccation in the Antarctic moss S. uncinata is mediated by the accumulation of ABA, the osmolytes proline and glycine betaine, and dehydrins (an LEA class 11 proteins). To demonstrate our hypothesis, S. uncinata was subjected to desiccation for 24 h (loss in 95% of water content), and the effects on its physiological, photosynthetic, antioxidant and biochemical parameters were determined. RESULTS: Our results showed an accumulation of ABA in response to water loss, and the activation of protective responses that involves an increment in levels of proline and glycine betaine, an increment in the activity of antioxidant enzymes such as SOD, CAT, APX and POD, and the accumulation of dehydrins proteins. CONCLUSION: The results showed, suggest that S. uncinata is a  desiccation-tolerant moss, property mediated by high cellular plasticity regulated by ABA.


Assuntos
Antioxidantes/análise , Bryopsida/fisiologia , Dessecação , Fotossíntese/fisiologia , Adaptação Fisiológica , Regiões Antárticas , Bryopsida/química , Bryopsida/classificação , Fatores de Tempo
18.
BMC Plant Biol ; 19(1): 258, 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31208344

RESUMO

BACKGROUND: It has been previously shown that oligo-carrageenan (OC) kappa increases growth, photosynthesis and activities of enzymes involved in basal and secondary metabolisms in Eucalyptus globulus. However, it is not known whether OC kappa may induce the activation of TOR pathway and the increase in expression of genes encoding proteins involved in photosynthesis and enzymes of basal and secondary metabolisms. RESULTS: E. globulus trees were sprayed on leaves with water (control) or with OC kappa 1 mg mL- 1, once a week, four times in total, and cultivated for 17 additional weeks (21 weeks in total). Treated trees showed a higher level of net photosynthesis than controls, beginning at week 3, a higher height, beginning at week 9, and those differences remained until week 21. In addition, treated trees showed an increase in the level of glucose beginning at week 1, trehalose at weeks 1-3, and in TOR-P level at week 1-2. On the other hand, transcripts encoding proteins involved in photosynthesis, and enzymes involved in glucose accumulation, C, N and S assimilation, and synthesis of secondary metabolites began at weeks 3-4 and with additional peaks at weeks 5-6, 8-11,13-14 and 17-19. Thus, OC kappa induced initial increases in glucose, trehalose and TOR-P levels that were followed by oscillatory increases in the level of transcripts coding for proteins involved in photosynthesis, and in basal and secondary metabolisms suggesting that initial increases in glucose, trehalose and TOR-P may trigger activation of gene expression. CONCLUSIONS: The stimulation of growth induced by OC kappa in E. globulus trees is due, at least in part, to activation of TOR pathway and the increase in expression of genes encoding proteins involved in photosynthesis and enzymes of basal metabolism.


Assuntos
Carragenina/farmacologia , Fotossíntese/efeitos dos fármacos , Metabolismo Basal/genética , Eucalyptus/genética , Eucalyptus/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glucose/metabolismo , Fotossíntese/genética , Proteínas de Plantas/metabolismo , Metabolismo Secundário/efeitos dos fármacos , Metabolismo Secundário/genética , Serina-Treonina Quinases TOR/metabolismo , Trealose/metabolismo
19.
Chemosphere ; 224: 111-119, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30818189

RESUMO

In this investigation, we assessed the effects of Cu and/or Cd excess on physiological and metabolic processes of the widespread seagrass Zostera marina. Adult were exposed to low Cd and Cu (0.89 and 0.8 µM, respectively) and high Cd and Cu (8.9 and 2.4 µM, respectively) for 6 d at: Control conditions; low Cu; high Cu; low Cd; high Cd; low Cd and low Cu; and high Cd and high Cu. Photosynthetic performance decreased under single and combined treatments, although effects were more negative under Cu than Cd. Total Cu accumulation was higher than Cd, under single and combined treatments; however, their accumulation was generally lower when applied together, suggesting competition among them. Levels of glutathione (GSH) and phytochelatins (PCs) followed patterns similar to metal accumulation, with up to PC5, displaying adaptations in tolerance. A metallothionein (MET) gene showed upregulation only at high Cd, low Cu, and high Cu. The expression of the enzymes glutathione reductase (GR), ascorbate peroxidase (APX), and catalase (CAT) was greatest at high Cu, and at high Cd and Cu together; the highest expression was under Cu, alone and combined. Both metals induced upregulation of the DNA methyltransferases CMT3 and DRM2, with the highest expression at single Cu. The DNA demethylation ROS1 was overexpressed in treatments containing high Cu, suggesting epigenetic modifications. The results show that under copper and/or cadmium, Z. marina was still biologically viable; certainly based, at least in part, on the induction of metal chelators, antioxidant defences and methylation/demethylation pathways of gene regulation.


Assuntos
Antioxidantes/metabolismo , Cádmio/farmacologia , Cobre/farmacologia , Metilação de DNA/efeitos dos fármacos , Metais/metabolismo , Fitoquelatinas/metabolismo , Zosteraceae/efeitos dos fármacos , Redes Reguladoras de Genes , Zosteraceae/enzimologia , Zosteraceae/metabolismo
20.
Phytochemistry ; 159: 90-101, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30605853

RESUMO

The main polysaccharide of the gel present in the leaves of or Aloe vera Burm.F., (Aloe barbadensis Miller) a xerophytic crassulacean acid metabolism (CAM) plant, is an acetylated glucomannan named acemannan. This polysaccharide is responsible for the succulence of the plant, helping it to retain water. In this study we determined using polysaccharide analysis by carbohydrate gel electrophoresis (PACE) that the acemannan is a glucomannan without galactose side branches. We also investigated the expression of the gene responsible for acemannan backbone synthesis, encoding a glucomannan mannosyltransferase (GMMT, EC 2.4.1.32), since there are no previous reports on GMMT expression under water stress in general and specifically in Aloe vera. It was found by in silico analyses that the GMMT gene belongs to the cellulose synthase-like A type-9 (CSLA9) subfamily. Using RT-qPCR it was found that the expression of GMMT increased significantly in Aloe vera plants subjected to water stress. This expression correlates with an increase of endogenous ABA levels, suggesting that the gene expression could be regulated by ABA. To corroborate this hypothesis, exogenous ABA was applied to non-water-stressed plants, resulting in a significant increase of GMMT expression after 48 h of ABA treatment.


Assuntos
Ácido Abscísico/farmacologia , Aloe/genética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Mananas/metabolismo , Metiltransferases/genética , Estresse Fisiológico , Água/metabolismo , Aloe/enzimologia , Aloe/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Domínio Catalítico , DNA Complementar/genética , Secas , Eletroforese em Gel de Amido/métodos , Cromatografia Gasosa-Espectrometria de Massas , Metiltransferases/química , Metiltransferases/metabolismo , Homologia de Sequência de Aminoácidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...