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X-ray multi-projection imaging (XMPI) has the potential to provide rotation-free 3D movies of optically opaque samples. The absence of rotation enables superior imaging speed and preserves fragile sample dynamics by avoiding the centrifugal forces introduced by conventional rotary tomography. Here, we present our XMPI observations at the ID19 beamline (ESRF, France) of 3D dynamics in melted aluminum with 1000 frames per second and 8 µm resolution per projection using the full dynamical range of our detectors. Since XMPI is a method under development, we also provide different tests for the instrumentation of up to 3000 frames per second. As the high-brilliance of 4th generation light-sources becomes more available, XMPI is a promising technique for current and future X-ray imaging instruments.
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Gene expression for Th1/Th2 cytokines (IL-4 and IFN-É£), regulatory cytokines (TGF-ß and IL-10) and the transcriptional factor FoxP3 was analyzed in the liver and hepatic lymph nodes (HLN) from sheep immunized with partially protective and non-protective vaccine candidates and challenged with Fasciola hepatica. FoxP3 T cells were also evaluated by immunohistochemistry (IHQ). The most remarkable difference between the partially protected vaccinated (V1) group and the non-protected vaccinated (V2) group was a more severe expansion of FoxP3 T cells recorded by IHQ in both the liver and HLN of the V2 group as compared to the V1 group, whereas no differences were found between the V2 group and the infected control (IC) group. Similar results were recorded for FoxP3 gene expression although significant differences among V1 and V2 groups were only significant in the HLN, while FoxP3 gene expression was very similar in the V2 and IC groups both in the liver and HLN. No significant differences for the remaining cytokines were recorded between the V1 and V2 groups, but in the liver the V2 group shows significant increases of IFN-É£ and IL-10 as compared to the uninfected control (UC) group whereas the V1 group did not. The lower expansion of FoxP3 T cells and lower increase of IFN-É£ and IL-10 in the partially protected vaccinated group may be related with lower hepatic lesions and fluke burdens recorded in this group as compared to the other two infected groups. The most relevant change in regulatory cytokine gene expression was the significant increase of TGF-ß in the liver of IC, V1 and V2 groups as compared to the UC group, which could be related to hepatic lesions.
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Citocinas , Fasciola hepatica , Fasciolíase , Fatores de Transcrição Forkhead , Doenças dos Ovinos , Animais , Fasciolíase/veterinária , Fasciolíase/prevenção & controle , Fasciolíase/imunologia , Fasciola hepatica/imunologia , Ovinos , Fatores de Transcrição Forkhead/metabolismo , Doenças dos Ovinos/prevenção & controle , Doenças dos Ovinos/imunologia , Doenças dos Ovinos/parasitologia , Citocinas/metabolismo , Fígado/parasitologia , Fígado/imunologia , Vacinas/imunologia , Vacinas/administração & dosagem , Células Th1/imunologia , Linfonodos/imunologia , Feminino , Células Th2/imunologiaRESUMO
Heavy carbon industries produce solid side stream materials that contain inorganic chemicals like Ca, Na, or Mg, and other metals such as Fe or Al. These inorganic compounds usually react efficiently with CO2 to form stable carbonates. Therefore, using these side streams instead of virgin chemicals to capture CO2 is an appealing approach to reduce CO2 emissions. Herein, we performed an experimental study of the mineral carbonation potential of three industrial steel slags via aqueous, direct carbonation. To this end, we studied the absorption capacities, reaction yields, and physicochemical characteristics of the carbonated samples. The absorption capacities and the reaction yields were analyzed through experiments carried out in a reactor specifically designed to work without external stirring. As for the physicochemical characterization, we used solid-state Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM). Using this reactor, the absorption capacities were between 5.8 and 35.3 g/L and reaction yields were in the range of 81-211 kg CO2/ton of slag. The physicochemical characterization of the solid products with solid FTIR, XRD and SEM indicated the presence of CaCO3. This suggests that there is potential to use the carbonated products in commercial applications.
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Resíduos Industriais , Aço , Aço/química , Resíduos Industriais/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Microscopia Eletrônica de Varredura , Difração de Raios X , Dióxido de Carbono/químicaRESUMO
It is commonly necessary to perform inferences on the difference, ratio, and odds ratio of two proportions p1 and p2 based on two independent samples. For this purpose, the most common asymptotic statistics are based on the score statistics (S-type statistics). As these do not correct the bias of the estimator of the product pi (1-pi), Miettinen and Nurminen proposed the MN-type statistics, which consist of multiplying the statistics S by (N-1)/N, where N is the sum of the two sample sizes. This paper demonstrates that the factor (N-1)/N is only correct in the case of the test of equality of two proportions, providing the estimation of the correct factor (AU-type statistics) and the minimum value of the same (AUM-type statistics). Moreover, this paper assesses the performance of the four-type statistics mentioned (S, MN, AU and AUM) in one and two-tailed tests, and for each of the three parameters cited (d, R and OR). We found that the AUM-type statistics are the best, followed by the MN type (whose performance was most similar to that of AU-type). Finally, this paper also provides the correct factors when the data are from a multinomial distribution, with the novelty that the MN and AU statistics are similar in the case of the test for the odds ratio.
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BACKGROUND: Depression and anxiety are common mental disorders among older adults, but they are frequently underdiagnosed. Attitudes towards seeking professional mental health care is one of the barriers to access to treatment. This study was aimed at assessing the attitudes towards seeking psychological help among older adults who are enrolled in primary care in Chile, and to determine the associated factors. METHODS: This cross-sectional study recruited 233 primary care users aged 65 or more years. The Attitudes Towards Seeking Professional Psychological Help was used. Reliability and factor analysis of this scale were carried out. The average scores of the scale and factors were calculated and compared, by selected variables. Multivariate linear regression was estimated to determine factors associated with attitudes towards seeking psychological help. RESULTS: Three factors were identified in the attitudes towards seeking psychological help: confidence in psychologists, coping alone with emotional problems, and predisposition to seek psychological help. On average, participants had a favorable attitude towards seeking psychological help, compared with previous research. Lower level of education, and risk of social isolation were inversely associated with these attitudes. CONCLUSION: Strategies to improve mental health literacy and social connection among older adults, could have an impact on factors that mediate the access to mental health care, such as attitudes towards seeking psychological help, among people who have a lower level of education or are at risk of social isolation.
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Vida Independente , Aceitação pelo Paciente de Cuidados de Saúde , Atenção Primária à Saúde , Humanos , Masculino , Idoso , Feminino , Chile/epidemiologia , Atenção Primária à Saúde/métodos , Estudos Transversais , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Vida Independente/psicologia , Idoso de 80 Anos ou mais , Atitude Frente a SaúdeRESUMO
BACKGROUND: Older adults face unique health challenges as they age, including physical and mental health issues and mood disorders. Negative emotions and social isolation significantly impact mental and physical health. To support older adults and address these challenges, healthcare professionals can use Information and Communication Technologies (ICTs) such as health monitoring systems with multiple sensors. These systems include digital biomarkers and data analytics that can streamline the diagnosis process and help older adults to maintain their independence and quality of life. METHOD: A design research methodology is followed to define a conceptual model as the main artifact and basis for the systematic design of successful systems centered on older adults monitoring within the health domain. RESULTS: The results include a conceptual model focused on older adults' Activities of Daily Living (ADLs) and Health Status, considering various health dimensions, including social, emotional, physical, and cognitive dimensions. We also provide a detailed instantiation of the model in real use cases to validate the usefulness and feasibility of the proposal. In particular, the model has been used to develop two health systems intended to measure the degree of the elders' frailty and dependence with biomarkers and machine learning. CONCLUSIONS: The defined conceptual model can be the basis to develop health monitoring systems with multiple sensors and intelligence based on data analytics. This model offers a holistic approach to caring for and supporting older adults as they age, considering ADLs and various health dimensions. We have performed an experimental and qualitative validation of the proposal in the field of study. The conceptual model has been instantiated in two specific case uses, showing the provided abstraction level and the feasibility of the proposal to build reusable, extensible and adaptable health systems. The proposal can evolve by exploiting other scenarios and contexts.
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Atividades Cotidianas , Qualidade de Vida , Humanos , Idoso , Projetos de Pesquisa , Nível de Saúde , BiomarcadoresRESUMO
This study investigates the acute effect of physical exercise simulating a standard pre-competitive warm-up on the response suppression and decision-making of football referees. Thirty-four referees (n = 17 - regional level; n = 17 - national level) participated in the study. A Stop-Signal Task (SST) and a decision-making video test were used to evaluate the referees' perceptual-cognitive functions. The findings revealed that the vigorous aerobic exercise acutely impacted basic cognitive functions, as indicated by decreased reaction time and decreased choice accuracy. However, higher-order cognitive functions such as response suppression and decision-making did not exhibit significant changes post-exercise. Based on these results, there is no evidence to suggest that a vigorous-intensity warm-up is likely to favour response suppression and decision-making factors in the initial phases of the game. National referees showed superior response suppression abilities (shorter stop-signal reaction times and lower probability of responding to the stop-signal) than regional referees, indicating that higher-level referees possess enhanced perceptual-cognitive skills, likely influenced by their experience. Further studies are required to determine whether these variables can be acutely improved through physical exercise. In this regard, our results suggest the need for alternative strategies in pre-competitive referee warm-ups if aiming to improve perceptual-cognitive skills in the initial phases of the game.
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Cognição , Tomada de Decisões , Tempo de Reação , Futebol , Exercício de Aquecimento , Humanos , Futebol/fisiologia , Futebol/psicologia , Adulto , Cognição/fisiologia , Masculino , Adulto JovemRESUMO
Movement control can be an indicator of how challenging a task is for the athlete, and can provide useful information to improve training efficiency and prevent injuries. This study was carried out to determine whether inertial measurement units (IMU) can provide reliable information on motion variability during strength exercises, focusing on the squat. Sixty-six healthy, strength-trained young adults completed a two-day protocol, where the variability in the squat movement was analyzed at two different loads (30% and 70% of one repetition maximum) using inertial measurement units and a force platform. The time series from IMUs and force platforms were analyzed using linear (standard deviation) and non-linear (detrended fluctuation analysis, sample entropy and fuzzy entropy) measures. Reliability was analyzed for both IMU and force platform using the intraclass correlation coefficient and the standard error of measurement. Standard deviation, detrended fluctuation analysis, sample entropy, and fuzzy entropy from the IMUs time series showed moderate to good reliability values (ICC: 0.50-0.85) and an acceptable error. The study concludes that IMUs are reliable tools for analyzing movement variability in strength exercises, providing accessible options for performance monitoring and training optimization. These findings have implications for the design of more effective strength training programs, emphasizing the importance of movement control in enhancing athletic performance and reducing injury risks.
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Treinamento Resistido , Adulto Jovem , Humanos , Treinamento Resistido/métodos , Reprodutibilidade dos Testes , Fenômenos Biomecânicos , Postura , Exercício FísicoRESUMO
ABSTRACT: Asencio, P, García-Valverde, A, Albaladejo-García, C, Beato, M, Moreno-Hernández, FJ, and Sabido, R. Analysis of concentric and eccentric power in flywheel exercises depending on the subjects' strength level and body mass. J Strength Cond Res 38(8): 1394-1400, 2024-The objective of this study is to describe how flywheel exercise mechanical outputs are affected by the athletes' body mass (BM) and strength level and by the exercise type. Forty-six recreational athletes came to a laboratory 3 times. On the first day, descriptive data, squat (1 repetition maximum: 1RM) and flywheel familiarization were performed. After a second day of familiarization, subjects performed a randomized flywheel exercise-testing protocol of squat and split squat exercises. The variables used for data analysis were peak concentric power and peak eccentric power, eccentric/concentric ratio, and their relationship with 1RM/BM. Subjects were assigned to a stronger or weaker group according to their 1RM/BM ratio. Group differences were found in absolute values of eccentric overload (EOL) ( p < 0.01; effect size [ES] = 0.51) and EOL/BM ( p < 0.01; ES = 0.46) only in the split squat. Absolute power values in the concentric phase showed differences between inertial load ( p < 0.01; ES = 0.41). The stronger group did not present significant differences between inertial loads during squat ( p < 0.01; ES = 0.46), but they showed different ratios with light inertias in comparison with the weaker group ( p < 0.01; ES = 0.46). There were significant differences between groups with light inertias in split squat (nondominant) and squat exercises ( p < 0.05; ES = 0.29) in the eccentric and concentric phases ( p < 0.116; ES = 0.20). Squat and split squat exercises present different profiles depending on the training level. In conclusion, it is recommended that practitioners perform a test to understand the inertial load-power profile (concentric, eccentric, and their ratio) for each exercise and also consider the user's strength level for selection of the inertial load and for the exercise to use in training.
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Força Muscular , Treinamento Resistido , Humanos , Força Muscular/fisiologia , Masculino , Treinamento Resistido/métodos , Adulto Jovem , Adulto , Feminino , Músculo Esquelético/fisiologia , Atletas , Peso CorporalRESUMO
Herein we study the economic performance of hydrochar and synthetic natural gas co-production from olive tree pruning. The process entails a combination of hydrothermal carbonization and methanation. In a previous work, we evidenced that standalone hydrochar production via HTC results unprofitable. Hence, we propose a step forward on the process design by implementing a methanation, adding value to the gas effluent in an attempt to boost the overall process techno-economic aspects. Three different plant capacities were analyzed (312.5, 625 and 1250 kg/hr). The baseline scenarios showed that, under the current circumstances, our circular economy strategy in unprofitable. An analysis of the revenues shows that hydrochar selling price have a high impact on NPV and subsidies for renewable coal production could help to boost the profitability of the process. On the contrary, the analysis for natural gas prices reveals that prices 8 times higher than the current ones in Spain must be achieved to reach profitability. This seems unlikely even under the presence of a strong subsidy scheme. The costs analysis suggests that a remarkable electricity cost reduction or electricity consumption of the HTC stage could be a potential strategy to reach profitability scenarios. Furthermore, significant reduction of green hydrogen production costs is deemed instrumental to improve the economic performance of the process. These results show the formidable techno-economic challenge that our society faces in the path towards circular economy societies.
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Carbono , Gás Natural , TemperaturaRESUMO
The expression of proinflammatory (IL-1ß, IFN-γ, TNF-α) and regulatory (IL-10, TGF-ß, IL-4) cytokines, as well as the transcription factor FoxP3, was quantified in the liver and hepatic lymph node (HLN) of sheep primoinfected and reinfected with Fasciola hepatica at early (4, 8 and 16 days post-infection [dpi]) and late (100 dpi) stages. The liver exerted a Th2 immune response at very early stages after the primoinfection with F. hepatica that induced the downregulation of IFN-γ, followed by a Th1/Th2/Treg response although the late stages were characterised by the expression of Th1/Th2 immune mediators. Contrarily, in reinfected sheep a robust mixed Th1/Th2/Treg immune response was found at very early stages meanwhile at late stages we observed a Th2/Treg immune response overcoming the expression of Th1 immune mediators. However, the HLN displayed a completely different Th1/Th2/Treg expression profile compared to the liver. Primoinfections with F. hepatica in HLN induced a mixed Th1/Th2/Treg environment from early stages, establishing a Th2 immune response at a late stage. However, the reinfected sheep exerted a Th2 immune response at early stages led by the IL-4 expression in opposition to the Th1/Th2/Treg found in the liver, meanwhile at late stages the HLN of reinfected sheep exerted a mixed Th1/Th2/Treg immune response. This is the first work publishing the expression of immune mediators in the liver and HLN from reinfected sheep with F. hepatica. The study of the immune responses exerted by the natural host in the target organs directly implied in the development of F. hepatica are crucial to better understand the immunopathogenesis of the fasciolosis being a key factor to develop effective vaccines.
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Fasciola hepatica , Fasciolíase , Doenças dos Ovinos , Ovinos , Animais , Fasciola hepatica/fisiologia , Interleucina-4 , Reinfecção/patologia , Reinfecção/veterinária , Linfócitos T Reguladores , Fasciolíase/veterinária , Fígado/patologia , Fatores de Transcrição , Imunidade , Linfonodos , Doenças dos Ovinos/patologiaRESUMO
OBJECTIVE: The aim of the study was to evaluate the effect of doxycycline- and dexamethasone-doped collagen membranes on the proliferation and differentiation of osteoblasts. BACKGROUND: Collagen barrier membranes are frequently used to promote bone regeneration and to boost this biological activity their functionalization with antibacterial and immunomodulatory substances has been suggested. METHODS: The design included commercially available collagen membranes doped with doxycycline (Dox-Col-M) or dexamethasone (Dex-Col-M), as well as undoped membranes (Col-M) as controls, which were placed in contact with cultured MG63 osteoblast-like cells (ATCC). Cell proliferation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay and differentiation by measuring the alkaline phosphatase (ALP) activity using spectrophotometry. Real-time quantitative polymerase chain reaction was used to study the expression of the genes: Runx-2, OSX, ALP, OSC, OPG, RANKL, Col-I, BMP-2, BMP-7, TGF-ß1, VEGF, TGF-ßR1, TGF-ßR2, and TGF-ßR3. Scanning electron microscopy was used to study osteoblast morphology. Data were assessed using one-way analysis of variance or Kruskal-Wallis tests, once their distribution normality was assessed by Kolmogorov-Smirnov tests (p > .05). Bonferroni for multiple comparisons were carried out (p < .05). RESULTS: Osteoblast proliferation was significantly enhanced in the functionalized membranes as follows: (Col-M < Dex-Col-M < Dox-Col-M). ALP activity was significantly higher on cultured osteoblasts on Dox-Col-M. Runx-2, OSX, ALP, OSC, BMP-2, BMP-7, TGF-ß1, VEGF, TGF-ßR1, TGF-ßR2, and TGF-ßR3 were overexpressed, and RANKL was down-regulated in osteoblasts cultured on Dox-Col-M. The osteoblasts cultured in contact with the functionalized membranes demonstrated an elongated spindle-shaped morphology. CONCLUSION: The functionalization of collagen membranes with Dox promoted an increase in the proliferation and differentiation of osteoblasts.
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Proteína Morfogenética Óssea 7 , Fator de Crescimento Transformador beta1 , Fator de Crescimento Transformador beta1/metabolismo , Proteína Morfogenética Óssea 7/metabolismo , Doxiciclina/farmacologia , Fator A de Crescimento do Endotélio Vascular/farmacologia , Diferenciação Celular , Colágeno/farmacologia , Colágeno/metabolismo , Osteoblastos , Proliferação de Células , Dexametasona/farmacologia , Fosfatase Alcalina/metabolismoRESUMO
BACKGROUND: Transient vision loss can be an alarming symptom owing to potentially serious etiologies such as thromboembolism or giant cell arteritis. Transient monocular vision loss (TVML) on awakening has been recently described as a benign phenomenon (Bouffard et al, 2017). Our objective was to describe the unique phenomenon of transient binocular vision loss (TBVL) on awakening. METHODS: Retrospective observational case series of 5 patients who experienced TBVL on awakening seen in the neuro-ophthalmology clinic at the Mayo Clinic between 2016 and 2020. Patients who described generalized blurred vision and those with monocular transient vision loss were excluded. RESULTS: The median age was 81.4 years (range, 68-92 years), and all were male. Every patient described a stereotyped transient bilateral central scotoma on awakening with slightly irregular borders and mild asymmetry between the 2 eyes lasting between 15 and 90 minutes. Frequency ranged from 3 to 7 times per week, and there was a median of 319 episodes (range, 126-728 episodes) before evaluation in the neuro-ophthalmology clinic. All patients had normal optic nerves, and no plaques were noted in the retinal vessels. All 5 had macular drusen, which were predominantly extrafoveal and mild. Two patients underwent electrophysiology testing, which were both normal on full-field electroretinogram (ERG), but there was blunted central wave forms on multifocal ERG. Two patients underwent dark adaptation testing, which showed both prolong and diminished dark adaptation. Neuroimaging and thromboembolic workup were unrevealing. CONCLUSIONS: TBVL is a distinct phenomenon from TMVL on awakening, which has a different demographic and symptomology. The etiology is unclear but seems to be a focal macular process in conjunction with an autoregulatory failure resulting in a supply-demand mismatch during low-light conditions.
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Escotoma , Transtornos da Visão , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Eletrorretinografia/métodos , Estudos Retrospectivos , Escotoma/diagnóstico , Escotoma/etiologia , Acuidade VisualRESUMO
BACKGROUND: To determine the incidence of carotid-cavernous fistula (CCF) and describe the neuro-ophthalmic manifestations and eventual clinical outcomes. METHODS: This was a population-based, retrospective cohort study using the Rochester Epidemiology Project to identify patients aged 18 years or older residing in Olmsted County, MN, diagnosed with CCF from 1997 to 2019. The medical records were reviewed for ophthalmic signs and symptoms, including conjunctival chemosis, proptosis, orbital bruit, diplopia, ophthalmoplegia, orbital pain, ocular hypertension, and blurred vision. Also determined was the number of patients with CCF found incidentally on neuroimaging, without clinical manifestations. RESULTS: Ten patients were diagnosed with a CCF between 1997 and 2019 with an overall incidence rate of 0.37 per 100,000 per year (95% CI 0.20-0.68). The median age was 50.5 years (range 23-74 years), 6 (60%) were female, and 9 were White and 1 patient was Korean. Three patients (30%) were asymptomatic and found incidentally on imaging that was obtained for unrelated reasons, and one patient's ocular details were unavailable because she passed away from severe head trauma. The following neuro-ophthalmologic or ocular manifestations were identified in the remaining 6 patients: chemosis/conjunctival injection (n = 6), cranial nerve (CN) VI palsy (n = 6), CN III palsy (n = 2), proptosis (n = 4), ocular/orbital pain (n = 3), audible orbital bruit (n = 2), ocular hypertension (n = 1), and blurred vision (n = 1). Of those patients with symptomatic CCFs, all underwent treatment except for one that spontaneously resolved. None of the patients suffered a stroke or cerebral hemorrhage. The 3 patients with incidentally discovered CCFs were asymptomatic and did not require treatment. CONCLUSIONS: This is the first population-based study to show a low incidence rate of CCFs, supporting the notion that it is an uncommon condition. Neuro-ophthalmic manifestations are common, especially chemosis/conjunctival injection and CN VI palsy. Up to a third of patients with CCF can be asymptomatic and may be found incidentally on neuroimaging during the evaluation for unrelated symptoms.
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Motor variability is a prominent feature of the human movement that, nowadays, can be easily measured through different sensors and analyzed using different types of variables, and it seems to be related to functional and adaptative motor behavior. It has been stated that motor variability is related to the system's flexibility needed to choose the right degrees of freedom (DoFs) to adapt to constant environmental changes. However, the potential relationship between motor variability and DoFs is unknown. The aim of this study was to analyze how motor variability, both the amount and structure, changes depending on the mechanical DoFs involved in the movement control. For this purpose, movement variability was assessed by a tracking sensor in five tasks with different DoFs, and the amount, using standard deviation, and the structure of variability, through fuzzy entropy and detrended fluctuation analysis, were also assessed. The results showed a higher amount of variability and a less predictable and more auto-correlated variability structure in the long-term when more mechanical DoFs are implied. The studies that analyze motor variability should consider the type of movement and the DoFs involved in the analyzed task since, as the findings have shown, both factors have a noticeable influence on the amount and the structure of motor variability.
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Aclimatação , Fenômenos Eletromagnéticos , Humanos , Entropia , MovimentoRESUMO
Allergic diseases are increasing around the world with unprecedented complexity and severity. One of the reasons is that genetically modified crops produce new potentially allergenic proteins. From this starting point, many researchers have paid attention to the development of tools to predict the allergenicity of new proteins. In this study, a novel approach is introduced for the prediction of food allergens based on Artificial Intelligence techniques: a pairwise sequence alignment with the FASTA program for feature extraction and the use of the Deep Learning technique known as Restricted Boltzmann Machines in combination with the Decision Tree method for the prediction process. The developed tool, called ALLERDET (publicly available at http://allerdet.frangam.com), overcomes the state-of-the-art methods. The performance of our method is: 98.46% sensitivity, 94.37% specificity and 97.26% accuracy), on a data set built from several publicly available sources.
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Alérgenos , Aplicativos Móveis , Inteligência Artificial , Produtos Agrícolas , Algoritmos , Plantas Geneticamente Modificadas , ProteínasRESUMO
Extracytoplasmic function (ECF) sigma factors are subunits of the RNA polymerase specialized in activating the transcription of a subset of genes responding to a specific environmental condition. The signal-transduction pathways where they participate can be activated by diverse mechanisms. The most common mechanism involves the action of a membrane-bound anti-sigma factor, which sequesters the ECF sigma factor, and releases it after the stimulus is sensed. However, despite most of these systems following this canonical regulation, there are many ECF sigma factors exhibiting a non-canonical regulatory mechanism. In this review, we aim to provide an updated and comprehensive view of the different activation mechanisms known for non-canonical ECF sigma factors, detailing their inclusion to the different phylogenetic groups and describing the mechanisms of regulation of some of their representative members such as EcfG from Rhodobacter sphaeroides, showing a partner-switch mechanism; EcfP from Vibrio parahaemolyticus, with a phosphorylation-dependent mechanism; or CorE from Myxococcus xanthus, regulated by a metal-sensing C-terminal extension.
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Regulação Bacteriana da Expressão Gênica , Fator sigma , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , RNA Polimerases Dirigidas por DNA/genética , RNA Polimerases Dirigidas por DNA/metabolismo , Filogenia , Fator sigma/genética , Fator sigma/metabolismoRESUMO
The synthesis of ß-galactosyl xylitol derivatives using immobilized LacA ß-galactosidase from Lactobacillus plantarum WCFS1 is presented. These compounds have the potential to replace traditional sugars by their properties as sweetener and taking the advantages of a low digestibility. The enzyme was immobilized on different supports, obtaining immobilized preparations with different activity and stability. The immobilization on agarose-IDA-Zn-CHO in the presence of galactose allowed for the conserving of 78% of the offered activity. This preparation was 3.8 times more stable than soluble. Since the enzyme has polyhistidine tags, this support allowed the immobilization, purification and stabilization in one step. The immobilized preparation was used in synthesis obtaining two main products and a total of around 68 g/L of ß-galactosyl xylitol derivatives and improving the synthesis/hydrolysis ratio by around 30% compared to that of the soluble enzyme. The catalyst was recycled 10 times, preserving an activity higher than 50%. The in vitro intestinal digestibility of the main ß-galactosyl xylitol derivatives was lower than that of lactose, being around 6 and 15% for the galacto-xylitol derivatives compared to 55% of lactose after 120 min of digestion. The optimal amount immobilized constitutes a very useful tool to synthetize ß-galactosyl xylitol derivatives since it can be used as a catalyst with high yield and being recycled for at least 10 more cycles.
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Proteínas de Bactérias/química , Lactobacillus plantarum/enzimologia , Xilitol , beta-Galactosidase/química , Catálise , Xilitol/análogos & derivados , Xilitol/químicaRESUMO
Hybrid materials based on polystyrene (PS) and green metal-organic frameworks (MOFs) were synthesized, characterized, and evaluated as potential sorbents in dispersive micro-solid-phase extraction (µ-dSPE). Among the resulting materials, the hybrid PS/DUT-67(Zr) was selected as the adequate extraction material for the monitoring of six personal care products in micellar cosmetic samples, combining the µ-dSPE method with ultra-high performance liquid chromatography (UHPLC) coupled to ultraviolet/visible detection (UV/Vis). Univariate studies and a factorial design were performed in the optimization of the microextraction procedure. The compromise optimum extraction conditions included 20 mg of PS/DUT-67(Zr) for 10 mL of sample, 2 min of extraction time, and two desorption steps using 100 µL of acetonitrile and 5 min assisted by vortex in each one. The validated µ-dSPE-UHPLC-UV/Vis method presented limits of detection and quantification down to 3.00 and 10.0 µg·L-1, respectively. The inter-day precision values were lower than 23.5 and 21.2% for concentration levels of 75 µg·L-1 and 650 µg·L-1, respectively. The hydrophobicity of the resulting PS/DUT-67(Zr) material was crucial for the improvement of its extraction capacity in comparison with its unitary components, showing the advantages of combining MOFs with other materials, getting new sorbents with interesting properties.
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BACKGROUND: Biostimulants are increasingly integrated into production systems with the goal of modifying physiological processes in plants to optimize productivity. Specifically, l-α-amino acid-based biostimulants enhance plant productivity through improved photosynthesis and increased assimilation of essential nutrients such as nitrogen (N). This element is a major component of fertilizers, which usually are applied in excess. Thus, the inefficient use of N fertilizers has generated a serious environmental pollution issue. The use of biostimulants has the potential to address problems related to N fertilization. Therefore, the objective of this study is to analyze whether two biostimulants based on l-α-amino acid (Terra Sorb® radicular and Terramin® Pro) designed by Bioiberica, S.A.U company can compensate deficient N fertilization and test its effect on lettuce plants. Growth, photosynthetic, N accumulation, and N use efficiency (NUE) parameters were analyzed on lettuce leaves. RESULTS: Results showed that regardless of N fertilization, the use of both biostimulants, especially Terramin® Pro, increased biomass production. Moreover, both biostimulants enhanced photosynthetic, NO3 - and total N accumulations as well as NUE parameters. CONCLUSION: Therefore, Terra Sorb® radicular and Terramin® Pro constitute a useful tool for crops development in N-limiting areas, and in intensive agricultural areas without N deficiency allowing the reduction of N inputs without impairing crop yields and reducing environmental impact. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.