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1.
Langmuir ; 38(49): 15226-15233, 2022 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-36454626

RESUMO

Multiphase aqueous-organic systems where a bicontinuous phase is in equilibrium with an excess organic and aqueous phase find various applications in industry. These systems─also known as Winsor III─are complex not only for the different phases that develop therein but also because they are multicomponent systems. In this work, we explore for the first time the use of a benchtop low-field single-sided NMR to determine the species distribution in Winsor III systems. The proposed methodology provides information at macroscopic and microscopic levels. In particular, we show the use of single-sided NMR to determine the phases' dimensions and the species distribution in a polymer-based bicontinuous system. The phases' dimensions and limits can be resolved with micrometric precision and are indicative of the bicontinuous phase stability. The species distribution is determined by means of spatially resolved NMR relaxation and diffusion experiments. It was observed that the salinity of the aqueous phase also impacts the species distribution in the bicontinuous system. Experiments show that the additive and the polymer are mainly located in the bicontinuous phase. As the salinity of the aqueous phase increases, the amount of organic components in the bicontinuous phase decreases as a consequence of the species distribution in the system. This influences the total amount of recovered organic liquid from the organic phase. The information is obtained in a relatively fast experiment and is relevant to the system's possible applications, such as enhanced oil recovery (EOR). This methodology is not only circumscribed to its application in EOR but can also be applied to the study of any emulsion or microemulsion systems without sample size or geometry constraints.

2.
Sensors (Basel) ; 22(20)2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36298178

RESUMO

Power line infrastructure is available almost everywhere. Positioning systems aim to estimate where a device or target is. Consequently, there may be an opportunity to use power lines for positioning purposes. This survey article reports the different efforts, working principles, and possibilities for implementing positioning systems relying on power line infrastructure for power line positioning systems (PLPS). Since Power Line Communication (PLC) systems of different characteristics have been deployed to provide communication services using the existing mains, we also address how PLC systems may be employed to build positioning systems. Although some efforts exist, PLPS are still prospective and thus open to research and development, and we try to indicate the possible directions and potential applications for PLPS.

3.
Molecules ; 27(14)2022 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-35889530

RESUMO

A simple and efficient one-pot, three-component synthetic method for the preparation of coumarin-3-carboxamides was carried out by the reaction of salicylaldehyde, aliphatic primary/secondary amines, and diethylmalonate. The protocol employs piperidine-iodine as a dual system catalyst and ethanol, a green solvent. The main advantages of this approach are that it is a metal-free and clean reaction, has low catalyst loading, and requires no tedious workup.


Assuntos
Iodo , Aminas , Catálise , Cumarínicos , Iodetos , Piperidinas
4.
Sensors (Basel) ; 21(1)2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33406684

RESUMO

The aim of this paper is to formulate the physical layer of the broadband and narrowband power line communication (PLC) systems described in standards IEEE 1901 and IEEE 1901.2, which address new communication technologies over electrical networks for Smart Grid and Internet of Things applications. Specifically, this paper presents a mathematical formulation by means of matrices of a transmitter and receiver system based on windowed OFDM. The proposed formulation is essential for obtaining the input-output relation, as well as an analysis of the interference present in the system. It is very useful for simulating PLC systems using software designed to operate primarily on whole matrices and arrays, such as Matlab. In addition, it eases the analysis and design of different receiver configurations, simply by modifying or adding a matrix. Since the relevant standards only describe the blocks corresponding to the transmitter, and leave the set-up of the receiver open to the manufacturer, we analysed four different possible schemes that include window functions in different configurations. In simulations, the behaviour of each of these schemes is analysed in terms of bit error and achievable data rates using artificial and real noises.

5.
Dermatol Ther ; 33(6): e14066, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32713119

RESUMO

The objective of the study was to evaluate efficacy and safety of ixekizumab in psoriasis patients under clinical practice conditions. Observational, retrospective, multicentre study that included patients with ixekizumab from March 2017 to March 2019. ≥ 90% reduction in the Psoriasis Area and Severity Index (PASI 90) and absolute PASI <2 were the parameters used to assess treatment response. Adverse events (AEs) were collected. Of the 301 patients included, 111 were women (36.9%), mean age was 48.5 (±13.5) years. Mean baseline PASI score was 13.5 (±7.7). More than half of the patients (68.5%) had received at least one biological drug before. At 3 months, 208 (76.5%) patients achieved PASI <2 and 156 (57.3%) PASI 90. At 12 months, 130 (73.4%) patients achieved absolute PASI <2 and 104 (58.7%) PASI 90. Multivariate analysis revealed that prior use of biologics was influential in achieving PASI <2 at both 3 and 12 months (OR 2.82, P = .006; OR 9.51, P < .001, respectively). Sixty-five patients (21.59%) exhibited at least one AE, injection site reaction was the most common (39; 36.8%). Likewise in trials, ixekizumab displayed an excellent profile of safety and efficacy also in real-life. Effectiveness appears superior in biologic-naive patients.


Assuntos
Fármacos Dermatológicos , Psoríase , Anticorpos Monoclonais Humanizados/efeitos adversos , Fármacos Dermatológicos/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psoríase/diagnóstico , Psoríase/tratamento farmacológico , Estudos Retrospectivos , Índice de Gravidade de Doença , Resultado do Tratamento
6.
Sensors (Basel) ; 20(11)2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32492938

RESUMO

During the last years, Electrocardiographic Imaging (ECGI) has emerged as a powerful and promising clinical tool to support cardiologists. Starting from a plurality of potential measurements on the torso, ECGI yields a noninvasive estimation of their causing potentials on the epicardium. This unprecedented amount of measured cardiac signals needs to be conditioned and adapted to current knowledge and methods in cardiac electrophysiology in order to maximize its support to the clinical practice. In this setting, many cardiac indices are defined in terms of the so-called bipolar electrograms, which correspond with differential potentials between two spatially close potential measurements. Our aim was to contribute to the usefulness of ECGI recordings in the current knowledge and methods of cardiac electrophysiology. For this purpose, we first analyzed the basic stages of conventional cardiac signal processing and scrutinized the implications of the spatial-temporal nature of signals in ECGI scenarios. Specifically, the stages of baseline wander removal, low-pass filtering, and beat segmentation and synchronization were considered. We also aimed to establish a mathematical operator to provide suitable bipolar electrograms from the ECGI-estimated epicardium potentials. Results were obtained on data from an infarction patient and from a healthy subject. First, the low-frequency and high-frequency noises are shown to be non-independently distributed in the ECGI-estimated recordings due to their spatial dimension. Second, bipolar electrograms are better estimated when using the criterion of the maximum-amplitude difference between spatial neighbors, but also a temporal delay in discrete time of about 40 samples has to be included to obtain the usual morphology in clinical bipolar electrograms from catheters. We conclude that spatial-temporal digital signal processing and bipolar electrograms can pave the way towards the usefulness of ECGI recordings in the cardiological clinical practice. The companion paper is devoted to analyzing clinical indices obtained from ECGI epicardial electrograms measuring waveform variability and repolarization tissue properties.


Assuntos
Mapeamento Potencial de Superfície Corporal , Eletrocardiografia , Pericárdio/fisiologia , Processamento de Sinais Assistido por Computador , Diagnóstico por Imagem , Humanos
7.
Sensors (Basel) ; 20(11)2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32485879

RESUMO

During the last years, attention and controversy have been present for the first commercially available equipment being used in Electrocardiographic Imaging (ECGI), a new cardiac diagnostic tool which opens up a new field of diagnostic possibilities. Previous knowledge and criteria of cardiologists using intracardiac Electrograms (EGM) should be revisited from the newly available spatial-temporal potentials, and digital signal processing should be readapted to this new data structure. Aiming to contribute to the usefulness of ECGI recordings in the current knowledge and methods of cardiac electrophysiology, we previously presented two results: First, spatial consistency can be observed even for very basic cardiac signal processing stages (such as baseline wander and low-pass filtering); second, useful bipolar EGMs can be obtained by a digital processing operator searching for the maximum amplitude and including a time delay. In addition, this work aims to demonstrate the functionality of ECGI for cardiac electrophysiology from a twofold view, namely, through the analysis of the EGM waveforms, and by studying the ventricular repolarization properties. The former is scrutinized in terms of the clustering properties of the unipolar an bipolar EGM waveforms, in control and myocardial infarction subjects, and the latter is analyzed using the properties of T-wave alternans (TWA) in control and in Long-QT syndrome (LQTS) example subjects. Clustered regions of the EGMs were spatially consistent and congruent with the presence of infarcted tissue in unipolar EGMs, and bipolar EGMs with adequate signal processing operators hold this consistency and yielded a larger, yet moderate, number of spatial-temporal regions. TWA was not present in control compared with an LQTS subject in terms of the estimated alternans amplitude from the unipolar EGMs, however, higher spatial-temporal variation was present in LQTS torso and epicardium measurements, which was consistent through three different methods of alternans estimation. We conclude that spatial-temporal analysis of EGMs in ECGI will pave the way towards enhanced usefulness in the clinical practice, so that atomic signal processing approach should be conveniently revisited to be able to deal with the great amount of information that ECGI conveys for the clinician.


Assuntos
Arritmias Cardíacas , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Arritmias Cardíacas/diagnóstico , Mapeamento Potencial de Superfície Corporal , Análise por Conglomerados , Humanos
8.
Health Qual Life Outcomes ; 17(1): 23, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-30704532

RESUMO

BACKGROUND: The daily diary Urticaria Activity Score (UAS) and its weekly score (UAS7) are widely used to assess signs and symptoms in patients with chronic spontaneous urticaria (CSU). The objective of this study was to assess the psychometric properties of a Spanish version of the once-daily UAS. METHODS: Observational study in patients ≥18 years old receiving usual care for CSU (daily or almost daily occurrence of generalized hives or angioedema for ≥6 weeks). Patients were included consecutively and completed the UAS, EQ-5D, and the Chronic Urticaria Quality of Life scale (CU-Q2oL) at two study visits 6 weeks apart. On each occasion, the UAS was completed once-daily for 7 consecutive days to be able to calculate the UAS7 score. Psychometric properties of reliability, construct validity, and responsiveness were assessed. The Minimal Important Difference (MID) was estimated for the UAS7 using anchor- and distribution-based approaches. RESULTS: Data from 166 patients was available for analysis (mean age 49 years, 65.7% female). Floor (5.4% of patients with the lowest possible score) and ceiling (1.2%) effects were low; 15% of patients had missing values. Internal consistency and test-retest reliability were good (Cronbach's alpha of 0.83 and an ICC of 0.84, respectively). Convergent validity was demonstrated through the pattern of correlations with the EQ-5D and CU-Q2oL and known groups' validity was demonstrated by the instrument's ability to discriminate between patients with different overall levels of urticaria severity, with between-group effect-sizes (ES) ranging from 0.36 to 1.19. The UAS7 proved responsive to change with effect sizes ranging from 0.3 to 1.52 in patients reporting improvement or deterioration in overall urticaria status. The MID for the UAS7 score was estimated at 7-8 points, on a scale of 0-42. CONCLUSIONS: The Spanish version of the UAS score has demonstrated a robust psychometric performance in patients with CSU managed in conditions of usual care. It can therefore be considered a suitable instrument to assess disease activity in clinical practice in Spanish-speaking patients. The Spanish version's reliability and validity are similar to those reported for other language versions of the once- and twice-daily variants of the UAS.


Assuntos
Medidas de Resultados Relatados pelo Paciente , Qualidade de Vida , Urticária/psicologia , Adulto , Idoso , Doença Crônica/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Psicometria , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Espanha , Traduções , Urticária/fisiopatologia
9.
Sensors (Basel) ; 18(11)2018 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-30400587

RESUMO

In recent years, a number of proposals for electrocardiogram (ECG) monitoring based on mobile systems have been delivered. We propose here an STM32F-microcontroller-based ECG mobile system providing both long-term (several weeks) Holter monitoring and 12-lead ECG recording, according to the clinical standard requirements for these kinds of recordings, which in addition can yield further digital compression at stages close to the acquisition. The system can be especially useful in rural areas of developing countries, where the lack of specialized medical personnel justifies the introduction of telecardiology services, and the limitations of coverage and bandwidth of cellular networks require the use of efficient signal compression systems. The prototype was implemented using a small architecture, with a 16-bits-per-sample resolution. We also used a low-noise instrumentation amplifier TI ADS1198, which has a multiplexer and an analog-to-digital converter (16 bits and 8 channels) connected to the STM32F processor, the architecture of which incorporates a digital signal processing unit and a floating-point unit. On the one hand, the system portability allows the user to take the prototype in her/his pocket and to perform an ECG examination, either in 12-lead controlled conditions or in Holter monitoring, according to the required clinical scenario. An app in the smartphone is responsible for giving the users a friendly interface to set up the system. On the other hand, electronic health recording of the patients are registered in a web application, which in turn allows them to connect to the Internet from their cellphones, and the ECG signals are then sent though a web server for subsequent and ubiquitous analysis by doctors at any convenient terminal device. In order to determine the quality of the received signals, system testing was performed in the three following scenarios: (1) The prototype was connected to the patient and the signals were subsequently stored; (2) the prototype was connected to the patient and the data were subsequently transferred to the cellphone; (3) the prototype was connected to the patient, and the data were transferred to the cellphone and to the web via the Internet. An additional benchmarking test with expert clinicians showed the clinical quality provided by the system. The proposed ECG system is the first step and paves the way toward mobile cardiac monitors in terms of compatibility with the electrocardiographic practice, including the long-term monitoring, the usability with 12 leads, and the possibility of incorporating signal compression at the early stages of the ECG acquisition.


Assuntos
Eletrocardiografia/instrumentação , Processamento de Sinais Assistido por Computador , Telemedicina/instrumentação , Calibragem , Telefone Celular , Eletrodos , Humanos , Internet , Reprodutibilidade dos Testes , Smartphone , Software
10.
Sensors (Basel) ; 18(5)2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29723990

RESUMO

Despite the wide literature on R-wave detection algorithms for ECG Holter recordings, the long-term monitoring applications are bringing new requirements, and it is not clear that the existing methods can be straightforwardly used in those scenarios. Our aim in this work was twofold: First, we scrutinized the scope and limitations of existing methods for Holter monitoring when moving to long-term monitoring; Second, we proposed and benchmarked a beat detection method with adequate accuracy and usefulness in long-term scenarios. A longitudinal study was made with the most widely used waveform analysis algorithms, which allowed us to tune the free parameters of the required blocks, and a transversal study analyzed how these parameters change when moving to different databases. With all the above, the extension to long-term monitoring in a database of 7-day Holter monitoring was proposed and analyzed, by using an optimized simultaneous-multilead processing. We considered both own and public databases. In this new scenario, the noise-avoid mechanisms are more important due to the amount of noise that exists in these recordings, moreover, the computational efficiency is a key parameter in order to export the algorithm to the clinical practice. The method based on a Polling function outperformed the others in terms of accuracy and computational efficiency, yielding 99.48% sensitivity, 99.54% specificity, 99.69% positive predictive value, 99.46% accuracy, and 0.85% error for MIT-BIH arrhythmia database. We conclude that the method can be used in long-term Holter monitoring systems.

11.
Chemphyschem ; 18(23): 3469-3477, 2017 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-28960697

RESUMO

The fluid dynamics of a liquid|liquid system inside a four-electrode electrochemical cell were studied by velocimetry magnetic resonance imaging (MRI) and flow propagator measurements. To characterize this system fully, three different cell configurations operating at two rotational frequencies were analyzed. Quantitative information about the stability of the liquid|liquid interface and the dynamics of the organic phase were determined. The NMR spectroscopy results were in agreement with the electrochemical measurements performed by using the same experimental setup.

12.
Sensors (Basel) ; 17(11)2017 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-29068362

RESUMO

Noise and artifacts are inherent contaminating components and are particularly present in Holter electrocardiogram (ECG) monitoring. The presence of noise is even more significant in long-term monitoring (LTM) recordings, as these are collected for several days in patients following their daily activities; hence, strong artifact components can temporarily impair the clinical measurements from the LTM recordings. Traditionally, the noise presence has been dealt with as a problem of non-desirable component removal by means of several quantitative signal metrics such as the signal-to-noise ratio (SNR), but current systems do not provide any information about the true impact of noise on the ECG clinical evaluation. As a first step towards an alternative to classical approaches, this work assesses the ECG quality under the assumption that an ECG has good quality when it is clinically interpretable. Therefore, our hypotheses are that it is possible (a) to create a clinical severity score for the effect of the noise on the ECG, (b) to characterize its consistency in terms of its temporal and statistical distribution, and (c) to use it for signal quality evaluation in LTM scenarios. For this purpose, a database of external event recorder (EER) signals is assembled and labeled from a clinical point of view for its use as the gold standard of noise severity categorization. These devices are assumed to capture those signal segments more prone to be corrupted with noise during long-term periods. Then, the ECG noise is characterized through the comparison of these clinical severity criteria with conventional quantitative metrics taken from traditional noise-removal approaches, and noise maps are proposed as a novel representation tool to achieve this comparison. Our results showed that neither of the benchmarked quantitative noise measurement criteria represent an accurate enough estimation of the clinical severity of the noise. A case study of long-term ECG is reported, showing the statistical and temporal correspondences and properties with respect to EER signals used to create the gold standard for clinical noise. The proposed noise maps, together with the statistical consistency of the characterization of the noise clinical severity, paves the way towards forthcoming systems providing us with noise maps of the noise clinical severity, allowing the user to process different ECG segments with different techniques and in terms of different measured clinical parameters.


Assuntos
Eletrocardiografia/métodos , Algoritmos , Artefatos , Eletrocardiografia/normas , Eletrocardiografia Ambulatorial , Humanos , Razão Sinal-Ruído
13.
Langmuir ; 32(8): 2067-74, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26847003

RESUMO

Evaporation kinetics of water confined in hierarchal polymeric porous media is studied by low field nuclear magnetic resonance (NMR). Systems synthesized with various degrees of cross-linker density render networks with similar pore sizes but different response when soaked with water. Polymeric networks with low percentage of cross-linker can undergo swelling, which affects the porosity as well as the drying kinetics. The drying process is monitored macroscopically by single-sided NMR, with spatial resolution of 100 µm, while microscopic information is obtained by measurements of spin-spin relaxation times (T2). Transition from a funicular to a pendular regime, where hydraulic connectivity is lost and the capillary flow cannot compensate for the surface evaporation, can be observed from inspection of the water content in different sample layers. Relaxation measurements indicate that even when the larger pore structures are depleted of water, capillary flow occurs through smaller voids.

14.
Langmuir ; 32(29): 7427-34, 2016 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-27341270

RESUMO

Hierarchical porous polymer systems are increasingly applied to catalysis, bioengineering, or separation technology because of the versatility provided by the connection of mesopores with percolating macroporous structures. Nuclear magnetic resonance (NMR) is a suitable technique for the study of such systems as it can detect signals stemming from the confined liquid and translate this information into pore size, molecular mobility, and liquid-surface interactions. We focus on the properties of water confined in macroporous polymers of ethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate [poly(EGDMA-co-HEMA)] with different amounts of cross-linkers, in which a substantial variation of hydroxyl groups is achieved. As soft polymer scaffolds may swell upon saturation with determined liquids, the use of NMR is particularly important as it measures the system in its operational state. This study combines different NMR techniques to obtain information on surface interactions of water with hydrophilic polymer chains. A transition from a surface-induced relaxation in which relaxivity depends on the pore size to a regime where the organic pore surface strongly restricts water diffusion is observed. Surface affinities are defined through the molecular residence times near the network surface.

15.
Soft Matter ; 11(45): 8879-86, 2015 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-26400774

RESUMO

In the traditional view of temperature-driven volume phase transitions in PNIPAM-based microgel solutions, a monotonic and sharp decrease in the particle size occurs upon heating the solution to above the volume phase transition temperature (VPTT). However, at sufficiently high microgel concentrations and under low salt conditions, our dynamic light scattering experiments reveal an unexpected non-monotonic evolution of the particle size when increasing the solution temperature. These findings show that poly(N-isopropylacrylamide-co-methacrylic acid) (P(NIPAM-co-MAA)) microgels swell upon heating the solution in the temperature range where NIPAM is water-soluble (i.e., below the VPPT). Further heating the microgel solution leads to microgel collapse as typically observed at temperatures above the VPTT. This novel behavior depends on the particle and salt concentration. We have observed the expected monotonic temperature-response of P(NIPAm-co-MAA) microgel solutions at low particle density and high salt concentration. To gain insights into the molecular origin of the unusual behavior of these microgel solutions, we have combined nuclear magnetic resonance studies and molecular-level theoretical calculations of the system. A delicate balance between inter-particle steric compressions and intra-microgel physical interactions and chemical equilibria determines the size of these microgels. Both steric compression, due to finite density, and hydrogen bond formation in the interior of the microgels favors a more compact particle. On the contrary, at the pH of the experiments the acid-base equilibrium constrains the polymer charge to increase, which favors particle swelling due to intra-microgel electrostatic repulsions. This interplay between physical interactions and chemical equilibria occurring at the nanometer length-scale determines the unusual thermal-induced swelling of P(NIPAM-co-MAA) microgels.

16.
Langmuir ; 30(14): 4129-36, 2014 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-24654600

RESUMO

NMR is a fast, nondestructive, and noninvasive technique that can provide information about the pore structure of macroporous polymer beads and the dynamics of liquids confined in them. In this work, we describe the study of the pore structure of the macroporous polymer of ethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate [poly(EGDMA-co-HEMA)] in the dry but also in the swollen state by measuring relaxation times of liquids contained in the polymer network. The results show that the pore architecture differs from the dry to the soaked state. The behavior of polar liquids during evaporation and deswelling dynamics is monitored and described. An internal migration of water from the swollen polymer mesh into expanding pores takes place. With this procedure it is possible to obtain information about the microscopic morphology behavior of the matrix during evaporation and deswelling. This information is of great interest with the aspect of possible and future applications for these types of materials.

17.
Curr Hypertens Rep ; 16(8): 463, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24924994

RESUMO

It has been two decades since the discovery of adiponectin, and today its role in insulin resistance, inflammation, and atherosclerosis are areas of major interest. Production of adiponectin is reduced in all inflammatory processes and states of insulin resistance such as obesity, type 2 diabetes mellitus, and coronary artery disease. Adiponectin regulates carbohydrate metabolism, and may also regulate vascular homeostasis by affecting important signaling pathways in endothelial cells and modulating inflammatory responses in the subendothelial space. Clinical studies have demonstrated a relationship between serum adiponectin concentrations and the activity of the renin-angiotensin-aldosterone system (RAAS), causing changes in blood pressure. Antihypertensive therapy with angiotensin II receptor blockers (ARBs) has been demonstrated to increase adiponectin levels in 3-6 months. Adiponectin has also been shown to play a role in cardiac injury in modulation of pro-survival reactions, cardiac energy metabolism, and inhibition of hypertrophic remodeling. The effects of adiponectin on the cardiovascular system are believed to be partially mediated by the activation of 5' adenosine monophosphate-activated protein kinase (AMPK) and cyclooxygenase-2 (COX-2) pathways, reducing endothelial cell apoptosis, promoting nitric oxide production, decreasing tumor necrosis factor-alpha (TNF-α) activity, and preventing atherosclerotic proliferation and smooth muscle cell migration. Further evaluation of biologically active forms of adiponectin and its receptor should help to clarify how obesity affects the cardiovascular system.


Assuntos
Adiponectina/metabolismo , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/fisiologia , Células Endoteliais/metabolismo , Hipertensão/tratamento farmacológico , Hipertensão/metabolismo , Humanos , Resistência à Insulina/fisiologia
18.
Comput Methods Programs Biomed ; 249: 108157, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38582037

RESUMO

BACKGROUND AND OBJECTIVE: T-wave alternans (TWA) is a fluctuation in the repolarization morphology of the ECG. It is associated with cardiac instability and sudden cardiac death risk. Diverse methods have been proposed for TWA analysis. However, TWA detection in ambulatory settings remains a challenge due to the absence of standardized evaluation metrics and detection thresholds. METHODS: In this work we use traditional TWA analysis signal processing-based methods for feature extraction, and two machine learning (ML) methods, namely, K-nearest-neighbor (KNN) and random forest (RF), for TWA detection, addressing hyper-parameter tuning and feature selection. The final goal is the detection in ambulatory recordings of short, non-sustained and sparse TWA events. RESULTS: We train ML methods to detect a wide variety of alternant voltage from 20 to 100 µV, i.e., ranging from non-visible micro-alternans to TWA of higher amplitudes, to recognize a wide range in concordance to risk stratification. In classification, RF outperforms significantly the recall in comparison with the signal processing methods, at the expense of a small lost in precision. Despite ambulatory detection stands for an imbalanced category context, the trained ML systems always outperform signal processing methods. CONCLUSIONS: We propose a comprehensive integration of multiple variables inspired by TWA signal processing methods to fed learning-based methods. ML models consistently outperform the best signal processing methods, yielding superior recall scores.


Assuntos
Arritmias Cardíacas , Eletrocardiografia Ambulatorial , Humanos , Eletrocardiografia Ambulatorial/métodos , Frequência Cardíaca , Arritmias Cardíacas/diagnóstico , Morte Súbita Cardíaca , Processamento de Sinais Assistido por Computador , Eletrocardiografia/métodos
19.
Am J Ther ; 20(4): 432-41, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23751328

RESUMO

Since the invention of electrocardiogram (ECG or EKG), its significance in the diagnosis of acute ischemic disease, chronic ischemic disease, and its contribution to cardiology has been no less than remarkable. The pathophysiology of acute coronary syndromes in most cases correlates with the clinical outcomes, biochemical findings (cardiac biomarkers), and electrocardiographic patterns. Electric activity in the myocardium is registered in the ECG describing positive deflections when the depolarization potential orientates positive charges to the recording electrode (approaches to it) and negative deflections when the depolarization potential orientates negative charges to the recording electrode and gets away from it. The abnormal Q-wave is the cornerstone of the myocardial infarction diagnosis after several days of the ischemic event. Findings in the ECG suggestive of ischemia and necrosis are ST elevation/depression and deep Q-waves, respectively, and the presence of a deep abnormal Q-wave in the ECG is evidence of necrotic areas and an inert myocardium, which is not capable to depolarize. Non-Q-wave myocardial infarction has been defined as acute myocardial infarction without a new-onset deep Q-wave on the ECG after day(s) of evolution, and because of the anatomopathological concept of infarction is usually related to necrosis, it results paradoxical to consider this widely known clinical and biochemical entity as a myocardial infarction when there is no evidence of necrosis in the ECG.


Assuntos
Síndrome Coronariana Aguda/diagnóstico , Eletrocardiografia/métodos , Infarto do Miocárdio/diagnóstico , Síndrome Coronariana Aguda/fisiopatologia , Síndrome Coronariana Aguda/terapia , Humanos , Infarto do Miocárdio/fisiopatologia , Infarto do Miocárdio/terapia , Miocárdio/patologia , Necrose , Fatores de Tempo
20.
Am J Ther ; 20(4): 399-413, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23011164

RESUMO

Obesity is a complex disease that affects all ethnic populations worldwide. The etiology of this disease is based on the interaction of genetic factors, environment and lifestyles indicators. Genetic contribution to the epidemic has gained attention from 2 sources: monogenic syndromes that display severe obesity, and the polygenic model of common obesity. Single mutations can render a syndrome with severe obesity resulting from alteration in central o peripheral appetite control mechanisms. The interaction of several polymorphisms and epigenetic modifications constitute the basic plot for common obesity, molecular ingredients that should not confuse the investigator-they make this riddle even harder to decipher.


Assuntos
Predisposição Genética para Doença , Estilo de Vida , Obesidade/genética , Animais , Epigênese Genética , Interação Gene-Ambiente , Humanos , Modelos Biológicos , Obesidade/epidemiologia , Obesidade/etiologia , Polimorfismo Genético , Índice de Gravidade de Doença
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