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Gadolinium-based contrast agents (GBCAs) are used in around 40 % of MRI procedures. Despite initial perceptions of minimal risk, their long-term use has emphasized the need to reduce toxicity and develop more efficient GBCAs with extended blood retention. Advancements in nanomaterials have led to improved GBCAs, enhancing MRI diagnostics. This study synthesizes and characterizes nanostructured gadolinium(III) micelles as superior MRI contrast agents. The complexes, [Gd(L)2], where L is a ligand of the N-alkyl-N-methylglucamine surfactant series (L8, L10 or L12, L10), form nanostructured micelles in aqueous solution. Gd(L8)2 and Gd(L10)2 relaxivities remained stable across concentrations. Compared to Gd-DTPA, Gd(III) micelles showed enhanced T1-weighted MRI contrast. Gd(L12)2 micelles exhibited cytotoxicity against B16F10 melanoma cells (IC50 42.5 ± 2.2 µM) and L292L929 fibroblasts (IC50 52.0 ± 2.5 µM), with a selectivity index of 1.2. In vivo application in mice brain T2-weighted images suggests nanostructured Gd(III) micelles are promising MRI contrast agents for targeting healthy organs or tumors.
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Speech decoding from non-invasive EEG signals can achieve relatively high accuracy (70-80%) for strictly delimited classification tasks, but for more complex tasks non-invasive speech decoding typically yields a 20-50% classification accuracy. However, decoder generalization, or how well algorithms perform objectively across datasets, is complicated by the small size and heterogeneity of existing EEG datasets. Furthermore, the limited availability of open access code hampers a comparison between methods. This study explores the application of a novel non-linear method for signal processing, delay differential analysis (DDA), to speech decoding. We provide a systematic evaluation of its performance on two public imagined speech decoding datasets relative to all publicly available deep learning methods. The results support DDA as a compelling alternative or complementary approach to deep learning methods for speech decoding. DDA is a fast and efficient time-domain open-source method that fits data using only few strong features and does not require extensive preprocessing.
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Spatiotemporal modulation (STM) is used in Ultrasonic Mid-Air Haptics to create compelling tactile sensations. The STM can create perceptually distinct sensations. We specified the sensations of a palm-size pattern by varying the focal point's speed and pattern sampling rate. Three sensations were specified, named as Dynamic, Vibratory and Uniform. A selective identification study was conducted to evaluate if the sensations were recognizable to the perception when presented individually and simultaneously (combined stimuli). The results support the STM's specification and the selective recognition of the sensations was possible for some combinations.
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Delay Differential Analysis (DDA) is a nonlinear method for analyzing time series based on principles from nonlinear dynamical systems. DDA is extended here to incorporate network aspects to improve the dynamical characterization of complex systems. To demonstrate its effectiveness, DDA with network capabilities was first applied to the well-known Rössler system under different parameter regimes and noise conditions. Network-motif DDA, based on cortical regions, was then applied to invasive intracranial electroencephalographic data from drug-resistant epilepsy patients undergoing presurgical monitoring. The directional network motifs between brain areas that emerge from this analysis change dramatically before, during, and after seizures. Neural systems provide a rich source of complex data, arising from varying internal states generated by network interactions.
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Encéfalo , Convulsiones , Humanos , Electrocorticografía/métodos , Dinámicas no Lineales , Electroencefalografía/métodosRESUMEN
Allergic contact dermatitis (ACD) is an inflammatory skin reaction whose incidence has increased and has been associated with a dietary pattern rich in saturated fats and refined sugars. Considering the increased incidence of ACD and the lack of research about the influence of a short-term high-sugar diet on dermatitis, our aim is to improve understanding of the influence of a high-sugar diet on ACD. We introduced a diet rich in sugar fifteen days before inducing contact dermatitis with oxazolone, in mice, and maintained it until the end of the experiment, which lasted three weeks in total. The dermatitis model increased cholesterol and triglycerides in the liver, and the combination of diet and dermatitis increased weight and worsened liver cholesterol measurements. Furthermore, the high-sugar diet increased the production of IL-6, IFN-γ and TNF-α in the skin, which may be involved in the increase in epithelial skin thickness observed in experimental ACD.
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Since the early 1970s, numerous systems exhibiting an algebraic structure resembling that of the 1963 Lorenz system have been proposed. These systems have occasionally yielded the same attractor as the Lorenz system, while in other cases, they have not. Conversely, some systems that are evidently distinct from the Lorenz system, particularly in terms of symmetry, have resulted in attractors that bear a resemblance to the Lorenz attractor. In this paper, we put forward a definition for Lorenz-like systems and Lorenz-like attractors. The former definition is based on the algebraic structure of the governing equations, while the latter relies on topological characterization. Our analysis encompasses over 20 explicitly examined chaotic systems.
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Differential equations serve as models for many physical systems. But, are these equations unique? We prove here that when a 3D system of ordinary differential equations for a dynamical system is transformed to the jerk or differential form, the jerk form is preserved in relation to a given variable and, therefore, the transformed system shares the time series of that given variable with the original untransformed system. Multiple algebraically different systems of ordinary differential equations can share the same jerk form. They may also share the same time series of the transformed variable depending on the parameters of the jerk form. Here, we studied 17 algebraically different Lorenz-like systems that share the same functional jerk form. There are groups of these systems that share the jerk parameters and, therefore, also have the same time series of the transformed variable.
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Anthropic stressors are among the greatest concerns in nature conservation. Among these, deforestation and urban expansion are major drivers of habitat loss, which is a major threat to biodiversity. Insects, the largest and most abundant group of animals, are declining at alarming rates. However, global estimates of the impact of anthropic stressors on insect abundance, richness, and traits are still lacking. Here, we performed a meta-analysis to estimate the impact of urbanization stressors on insect abundance, diversity, and traits. Our design focused on the effects of urbanization on moderators such as insects' activity periods, climatic zones, development stages, ecosystem, functional roles, mobility, orders, and life history. We found that insects are negatively affected by urban stressors across most moderators evaluated. Our research estimated that in insects, urbanization resulted in a mean decrease of 42 % in abundance, 40 % in richness, and 24 % in trait effects, compared to a conserved area. Even though in general there was greater loss in abundance than in richness, each moderator was affected by different means and to varying degrees, which results from artificial lighting at night as well as land use. Our study highlights the importance of promoting better protection of insect biodiversity in the future from the enormous loss in biodiversity reported in >500 papers assessed.
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Elevated humidity levels in medical, food, and pharmaceutical products may reduce the products' shelf life, trigger bacterial growth, and even lead to complete spoilage. In this study, we report a humidity indicator that mechanically bends and rolls itself irreversibly upon exposure to high humidity conditions. The indicator is made of two food-grade polymer films with distinct ratios of a milk protein, casein, and a plasticizer, glycerol, that are physically attached to each other. Based on the thermogravimetric analysis and microstructural characterization, we hypothesize that the bending mechanism is a result of hygroscopic swelling and consequent counter diffusion of water and glycerol. Guided by this mechanism, we demonstrate that the rolling behavior, including response time and final curvature, can be tuned by the geometric dimensions of the indicator. As the proposed indicator is made of food-grade ingredients, it can be placed directly in contact with perishable products to report exposure to undesirable humidity inside the package, without the risk of contaminating the product or causing oral toxicity in case of accidental digestion, features that commercial inedible electronic and chemo-chromatic sensors cannot provide presently.
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An Auditory Steady-State Response (ASSR) is a valuable tool for determining auditory thresholds in individuals who are either unable or unwilling to cooperate with conventional behavioral testing methods. This study proposes a sequential test technique for automatic detection of ASSRs, incorporating a non-detection stopping criterion. The electrophysiological thresholds of a normal hearing volunteer were established using data collected from multichannel EEG signals. The detection probabilities and critical values were obtained via Monte Carlo simulations. Remarkably, application of the non-detection stopping criterion resulted in a 60% reduction in exam time in the absence of a response. These findings clearly demonstrate the significant potential of the sequential test in enhancing the performance of automatic audiometry.
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Objective. Automatic detection of Electrocardiograms (ECG) quality is fundamental to minimize costs and risks related to delayed diagnosis due to low ECG quality. Most algorithms to assess ECG quality include non-intuitive parameters. Also, they were developed using data non-representative of a real-world scenario, in terms of pathological ECGs and overrepresentation of low-quality ECG. Therefore, we introduce an algorithm to assess 12-lead ECG quality, Noise Automatic Classification Algorithm (NACA) developed in Telehealth Network of Minas Gerais (TNMG).Approach. NACA estimates a signal-to-noise ratio (SNR) for each ECG lead, where 'signal' is an estimated heartbeat template, and 'noise' is the discrepancy between the template and the ECG heartbeat. Then, clinically-inspired rules based on SNR are used to classify the ECG as acceptable or unacceptable. NACA was compared with Quality Measurement Algorithm (QMA), the winner of Computing in Cardiology Challenge 2011 (ChallengeCinC) by using five metrics: sensitivity (Se), specificity (Sp), positive predictive value (PPV),F2, and cost reduction resulting from adoption of the algorithm. Two datasets were used for validation: TestTNMG, consisting of 34 310 ECGs received by TNMG (1% unacceptable and 50% pathological); ChallengeCinC, consisting of 1000 ECGs (23% unacceptable, higher than real-world scenario).Main results. Both algorithms reached a similar performance on ChallengeCinC, although NACA performed considerably better than QMA in TestTNMG (Se = 0.89 versus 0.21; Sp = 0.99 versus 0.98; PPV = 0.59 versus 0.08;F2= 0.76 versus 0.16 and cost reduction 2.3 ± 1.8% versus 0.3 ± 0.3%, respectively).Significance. Implementing of NACA in a telecardiology service results in evident health and financial benefits for the patients and the healthcare system.
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Procesamiento de Señales Asistido por Computador , Telemedicina , Humanos , Electrocardiografía/métodos , Frecuencia Cardíaca , AlgoritmosRESUMEN
Isthmic spondylolisthesis is a condition characterized by the subluxation of one vertebral body over the adjacent inferior vertebral body, secondary to a defect in the pars interarticularis. This paper reports two cases of young acrobatic gymnasts who presented with long-term, progressive lumbosciatic pain and lower limb dysesthesia. One gymnast presented with additional neurogenic bladder dysfunction. Diagnostic testing revealed L5-S1 spondylolisthesis due to bilateral isthmic lysis in both gymnasts. Both underwent L4-S2 fixation followed by L5-S1 transdiscal arthrodesis with Rialto sacroiliac fusion system (Medtronic®, Minneapolis, MN, USA). Favorable evolution of neuromotor symptoms was observed after rehabilitation, with less residual neurological impairment in the case of higher-grade spondylolisthesis. This case series aims to emphasize the importance of recognizing this pathology in athletes as well as its correct management. Early surgical intervention can prevent the onset and progression of neurological deficits.
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The multichannel objective response detection (MORD) techniques are statistical methods, which use information from more than one electroencephalography (EEG) channel, to infer the presence of evoked potential. However, the correlation level between the channels can lead to a decrease in MORD performance, such as an increase in the false positive (FP) rate and/or a decrease in the detection rate (DR). The present study aims to propose a method to deal with the correlations in the multichannel EEG. The method consists of making an adjustment in the Monte Carlo simulation, considering the information between channels. The MORD techniques with and without the new method were applied to an auditory steady-state response (ASSR) database, composed of the EEG multichannel of eleven volunteers during multifrequency stimulation. The proposed method kept the FP rate at values equal to or less than the significance level of the test and led to an increase of 8.51% in the DR in relation to non-application of the method. Results of this study indicate that the proposed method is an alternative to deal with the effect of the correlation between channels in situations where MORD techniques are applied.
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Electroencefalografía , Potenciales Evocados , Humanos , Método de Montecarlo , Electroencefalografía/métodos , Simulación por Computador , Potenciales Evocados Auditivos/fisiología , Estimulación AcústicaRESUMEN
PURPOSE: In the present study, a new procedure to perform automatic audiometry using multifrequency Auditory Steady-State Response (ASSR) is proposed. METHODS: The automatic audiometry procedure consists of detecting the presence of multifrequency ASSR in real-time using the sequential test strategy and by adjusting the stimulus intensity independently. The ASSR audiometric thresholds of 18 adult volunteers with normal hearing were determined by automatically (four simultaneous frequencies per ear) at modulation frequencies in the 80 Hz range. The exam time and the difference between ASSR thresholds and pure-tone behavioural hearing thresholds were estimated as performance measures. RESULTS: The results showed that automatic audiometry can reduce the number of intensity levels used to obtain the ASSR threshold by up to 58% when compared to audiometry without using the techniques applied in automatic audiometry. In addition, the average of the difference between ASSR thresholds and Pure-Tone Behavioural Hearing thresholds was around 19 dB, which is similar to the results reported in similar studies. CONCLUSIONS: The audiometric procedure proposed in this study is fully automatic, i.e., does not require any human supervision throughout the exam, and is able to significantly reduce the conventional exam time.
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Audiometría de Respuesta Evocada , Audición , Adulto , Humanos , Audiometría de Tonos Puros/métodos , Audiometría de Respuesta Evocada/métodos , Umbral Auditivo/fisiología , Audición/fisiología , Voluntarios , Potenciales Evocados Auditivos del Tronco Encefálico/fisiología , Estimulación AcústicaRESUMEN
ABSTRACT: Balikian, P, Gomes de Araujo, G, Prado, ES, Ryan Geraldes, AA, Marinho de Lima, AH, and Mendes, EV. Anaerobic threshold in stand-up paddle: comparison between direct and alternative methods. J Strength Cond Res 36(7): 1896-1900, 2022-The purpose of this study was to test the validity of alternative protocols, mean velocity during 30 minutes of continuous effort (V30min) and critical velocity (CV), to estimate the anaerobic threshold in stand-up paddle (SUP). Eight athletes performed: 3 maximal efforts at 400-, 500-, and 800-m distances to determine CV values, using the distance-time relationship; 3 efforts at 85, 90, and 100% of maximal 500-m effort to determine the velocity related to 3.5 mmol·L-1 of lactate, assumed as the onset of blood lactate accumulation (OBLA) and; a 30-minute continuous effort to determine the V30min. All evaluations were separated by 48 hours, with the athletes using their own boards and paddles in the water. No differences were observed between the OBLA (2.35 ± 0.13 m·s-1) and alternative methods (CV: 2.42 ± 0.20 m·s-1; p = 0.10 and V30min: 2.32 ± 0.13 m·s-1; p = 0.63). Although strong correlations were observed between the OBLA and alternative methods (CV: r = 0.84 and V30min: r = 0.94), the limits of agreement were higher in CV (±0.23 m·s-1) than V30min (±0.08 m·s-1). These results demonstrate that both the CV and V30min are valid to estimate the OBLA. In view of the specificity of SUP and the high levels of agreement, the use of the V30min is recommended to prescribe training intensities.
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Umbral Anaerobio , Prueba de Esfuerzo , Atletas , Prueba de Esfuerzo/métodos , Humanos , Ácido LácticoRESUMEN
Background: The SARS-CoV-2 pandemic reverberated, posing health and social hygiene obstacles throughout the globe. Mutant lineages of the virus have concerned scientists because of convergent amino acid alterations, mainly on the viral spike protein. Studies have shown that mutants have diminished activity of neutralizing antibodies and enhanced affinity with its human cell receptor, the ACE2 protein. Methods: Hence, for real-time measuring of the impacts caused by variant strains in such complexes, we implemented E-Volve, a tool designed to model a structure with a list of mutations requested by users and return analyses of the variant protein. As a proof of concept, we scrutinized the spike-antibody and spike-ACE2 complexes formed in the variants of concern, B.1.1.7 (Alpha), B.1.351 (Beta), and P.1 (Gamma), by using contact maps depicting the interactions made amid them, along with heat maps to quantify these major interactions. Results: The results found in this study depict the highly frequent interface changes made by the entire set of mutations, mainly conducted by N501Y and E484K. In the spike-Antibody complex, we have noticed alterations concerning electrostatic surface complementarity, breaching essential sites in the P17 and BD-368-2 antibodies. Alongside, the spike-ACE2 complex has presented new hydrophobic bonds. Discussion: Molecular dynamics simulations followed by Poisson-Boltzmann calculations corroborate the higher complementarity to the receptor and lower to the antibodies for the K417T/E484K/N501Y (Gamma) mutant compared to the wild-type strain, as pointed by E-Volve, as well as an intensification of this effect by changes at the protein conformational equilibrium in solution. A local disorder of the loop α1'/ß1', as well its possible effects on the affinity to the BD-368-2 antibody were also incorporated to the final conclusions after this analysis. Moreover, E-Volve can depict the main alterations in important biological structures, as shown in the SARS-CoV-2 complexes, marking a major step in the real-time tracking of the virus mutant lineages. E-Volve is available at http://bioinfo.dcc.ufmg.br/evolve.
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COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , Enzima Convertidora de Angiotensina 2/genética , Glicoproteína de la Espiga del Coronavirus/genética , COVID-19/epidemiología , Anticuerpos Neutralizantes , MutaciónRESUMEN
In 1994, Sprott [Phys. Rev. E 50, 647-650 (1994)] proposed a set of 19 different simple dynamical systems producing chaotic attractors. Among them, 14 systems have a single nonlinear term. To the best of our knowledge, their diffeomorphical equivalence and the topological equivalence of their chaotic attractors were never systematically investigated. This is the aim of this paper. We here propose to check their diffeomorphical equivalence through the jerk functions, which are obtained when the system is rewritten in terms of one of the variables and its first two derivatives (two systems are thus diffeomorphically equivalent when they have exactly the same jerk function, that is, the same functional form and the same coefficients). The chaotic attractors produced by these systems-for parameter values close to the ones initially proposed by Sprott-are characterized by a branched manifold. Systems B and C produce chaotic attractors, which are observed in the Lorenz system and are also briefly discussed. Those systems are classified according to their diffeomorphical and topological equivalence.
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Dinámicas no LinealesRESUMEN
This document was prepared by the College of Orthopedics of the Portuguese Medical Association with the aim of developing the guidelines on the resumption of elective surgical activity in Orthopedics during the COVID-19 pandemic. It sets the criteria that allow the prioritization of surgeries according to the severity of the clinical situation, based on existing and published classifications. Moreover, it provides an organizational model for patient preparation and describes the patient pathways in the preoperative, intraoperative and postoperative periods. It also describes safety rules for elective surgery and a model for monitoring patients after discharge according to scientific evidence.
Este documento foi elaborado pelo Colégio de Ortopedia da Ordem dos Médicos com o objetivo de estabelecer as orientações sobre a retoma da atividade cirúrgica programada em Ortopedia durante a pandemia COVID-19. As presentes normas de orientação: a) definem os critérios que permitem a priorização das cirurgias de acordo com a gravidade da situação clínica, com base em classificações existentes e publicadas; b) fornecem um modelo de organização para a preparação dos doentes, descrevendo os circuitos do doente nos períodos pré-operatório, intraoperatório e pós-operatório; c) realçam as regras de segurança para a realização de cirurgias e desenham um modelo de acompanhamento após a alta de acordo com a evidência científica.
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COVID-19/prevención & control , Procedimientos Ortopédicos , Ortopedia , Guías de Práctica Clínica como Asunto , COVID-19/epidemiología , Humanos , Salud Laboral , Procedimientos Ortopédicos/normas , Pandemias/prevención & control , Seguridad del Paciente , Portugal , SARS-CoV-2 , Sociedades MédicasRESUMEN
Properties such as shear modulus, gelation time, structure of supramolecular hydrogels are strongly dependent on self-assembly, gelation triggering mechanism and processes used to form the gel. In our work we extend reported rheology analysis methodologies to pH-triggered supramolecular gels to understand structural insight using a model system based on N-N' Dibenzoyl-L-Cystine pH-triggered hydrogelator and Glucono-δ-Lactone as the trigger. We observed that Avrami growth model when applied to time-sweep rheological data of gels formed at lower trigger concentrations provide estimates of fractal dimension which agree well compared with visualization of the microstructure as seen via Confocal Laser Scanning Microscopy, for a range of gelator concentrations.