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1.
Nutrients ; 15(19)2023 Sep 26.
Article in English | MEDLINE | ID: mdl-37836432

ABSTRACT

Inflammatory bowel diseases (IBD) are chronic conditions arising from an intricate interplay of genetics and environmental factors, and are associated with gut dysbiosis, inflammation, and gut permeability. In this study, we investigated whether the inflammatory potential of the diet is associated with the gut microbiota profile, inflammation, and permeability in forty patients with IBD in clinical remission. The dietary inflammatory index (DII) score was used to assess the inflammatory potential of the diet. The fecal microbiota profile was analyzed using 16SrRNA (V3-V4) gene sequencing, while fecal zonulin and calprotectin levels were measured with enzyme-linked immunosorbent assays. We found a positive correlation between the DII score and elevated calprotectin levels (Rho = 0.498; p = 0.001), but not with zonulin levels. Although α- and ß-diversity did not significantly differ across DII quartiles, the most pro-inflammatory diet group exhibited a higher fecal abundance of Veillonella rogosae (p = 0.026). In addition, the abundance of some specific bacteria sequences showed an exponential behavior across DII quartiles and a correlation with calprotectin or zonulin levels (p ≤ 0.050). This included a positive correlation between sq702. Veillonella rogosae and fecal calprotectin levels (Rho = 0.419, p = 0.007). DII, calprotectin, and zonulin levels were identified as significant predictors of 6-month disease relapse (p ≤ 0.050). Our findings suggest a potential relationship of a pro-inflammatory diet intake with Veillonella rogosae and calprotectin levels in IBD patients in clinical remission, which may contribute to disease relapse.


Subject(s)
Inflammatory Bowel Diseases , Humans , Biomarkers , Inflammation , Feces/microbiology , Chronic Disease , Diet , Recurrence , Leukocyte L1 Antigen Complex
2.
Nutrients ; 15(18)2023 Sep 08.
Article in English | MEDLINE | ID: mdl-37764696

ABSTRACT

Oxidative stress is a common characteristic of psychiatric, neurological, and neurodegenerative disorders. Therefore, compounds that are neuroprotective and reduce oxidative stress may be of interest as novel therapeutics. Phenolic, flavonoid and anthocyanin content, ORAC and DPPH free radical scavenging, and Cu2+ and Fe2+ chelating capacities were examined in variations (fresh/capsule) of Queen Garnet plum (QGP, Prunus salicina), black pepper (Piper nigrum) clove (Syzygium aromaticum), elderberry (Sambucus nigra), lemon balm (Melissa officinalis) and sage (Salvia officinalis), plus two blends (Astralagus membranaceus-lemon balm-rich, WC and R8). The ability of samples to prevent and treat H2O2-induced oxidative stress in SH-SY5Y cells was investigated. Pre-treatment with WC, elderberry, QGP, and clove prevented the oxidative stress-induced reduction in cell viability, demonstrating a neuroprotective effect. Elderberry increased cell viability following oxidative stress induction, demonstrating treatment effects. Clove had the highest phenolic and flavonoid content, DPPH, and Cu2+ chelating capacities, whereas QGP and elderberry were highest in anthocyanins. Black pepper had the highest ORAC and Fe2+ chelating capacity. These findings demonstrate that plant extracts can prevent and treat oxidative stress-induced apoptosis of neuron-like cells in vitro. Further research into phytochemicals as novel therapeutics for oxidative stress in the brain is needed.


Subject(s)
Melissa , Neuroblastoma , Neuroprotective Agents , Sambucus , Humans , Antioxidants/pharmacology , Neuroprotective Agents/pharmacology , Anthocyanins , Hydrogen Peroxide , Flavonoids/pharmacology
3.
Eur J Clin Nutr ; 76(3): 469-476, 2022 03.
Article in English | MEDLINE | ID: mdl-34230633

ABSTRACT

BACKGROUND/OBJECTIVES: Experimental and clinical studies have shown that vitamins A and E can inhibit cancer formation and progression. The unfavourable status of these vitamins can represent risk factors for the disease. This study aimed to evaluate the associations between the nutritional status of vitamins A and E (serum levels and dietary intake) and histopathological outcomes in Papillary Thyroid Carcinoma (PTC) patients. SUBJECTS/METHODS: We applied a cross-sectional study (2017-2018) and quantified retinol (ROH) and α-tocopherol (TOH) serum levels and vitamins dietary intake of 46 PTC patients. Serum vitamins were quantified by high efficiency liquid chromatography and vitamins dietary intake was analyzed by 24-hr dietary recalls. RESULTS: Patients with lower ROH serum levels were more likely to present lymph node metastasis and/or angiolymphatic invasion (p = 0.025). In addition, higher vitamin A and vitamin E intake are related to the absence of extrathyroidal extension (p = 0.013) and lymph node metastasis (p = 0.007), respectively. Our findings suggest that a ROH serum level greater than 2.65 µmol/L in PTC patients may be a protective factor against the presence of lymph node metastasis and angiolymphatic invasion. In addition, vitamin A and E intake may protect against extrathyroidal extension and lymph node metastasis. CONCLUSIONS: A favourable nutritional status (higher serum levels and/or intake) of vitamin A and E may be associated with less aggressive tumours in PTC patients.


Subject(s)
Thyroid Neoplasms , Vitamin A , Cross-Sectional Studies , Humans , Nutritional Status , Prognosis , Retrospective Studies , Risk Factors , Thyroid Cancer, Papillary/pathology , Thyroid Neoplasms/pathology , Vitamins
4.
J Vis Exp ; (159)2020 05 24.
Article in English | MEDLINE | ID: mdl-32510476

ABSTRACT

Aluminum-oxide (Al2O3) is a low cost, easily processable and high dielectric constant insulating material that is particularly appropriate for use as the dielectric layer of thin-film transistors (TFTs). Growth of aluminum-oxide layers from anodization of metallic aluminum films is greatly advantageous when compared to sophisticated processes such as atomic layer deposition (ALD) or deposition methods that demand relatively high temperatures (above 300 °C) such as aqueous combustion or spray-pyrolysis. However, the electrical properties of the transistors are highly dependent on the presence of defects and localized states at the semiconductor/dielectric interface, which are strongly affected by the manufacturing parameters of the anodized dielectric layer. To determine how several fabrication parameters influence the device performance without performing all possible combination of factors, we used a reduced factorial analysis based on a Plackett-Burman design of experiments (DOE). The choice of this DOE permits the use of only 12 experimental runs of combinations of factors (instead of all 256 possibilities) to obtain the optimized device performance. The ranking of the factors by the effect on device responses such as the TFT mobility is possible by applying analysis of variance (ANOVA) to the obtained results.


Subject(s)
Aluminum Oxide/chemistry , Electric Conductivity , Electrodes , Transistors, Electronic , Equipment Design
5.
ACS Comb Sci ; 21(5): 370-379, 2019 05 13.
Article in English | MEDLINE | ID: mdl-30892872

ABSTRACT

The present study reports a two-level multivariate analysis to optimize the production of anodized aluminum oxide (Al2O3) dielectric films for zinc oxide thin-film transistors (TFTs). Fourteen performance parameters were measured and analysis of variance (ANOVA) of the combined responses has been applied to identify how the Al2O3 dielectric fabrication process influences the electrical properties of the TFTs. Using this approach, the levels for the manufacturing factors to achieve optimal overall device performance have been identified and ranked. The cross-checked analysis of the TFT performance parameters demonstrated that the appropriate control of the anodization process can have a higher impact on TFT performance than the use of traditional methods of surface treatment of the dielectric layer. Flexible electronics applications are expected to grow substantially over the next 10 years. Given the complexity and challenges of new flexible electronics components, this "multivariate" approach could be adopted more widely by the industry to improve the reliability and performance of such devices.


Subject(s)
Aluminum Oxide/chemistry , Transistors, Electronic , Zinc Oxide/chemistry , Combinatorial Chemistry Techniques , Electrochemical Techniques , Electrodes , Multivariate Analysis
6.
Gait Posture ; 60: 268-272, 2018 02.
Article in English | MEDLINE | ID: mdl-28712512

ABSTRACT

This study investigated whether women with patellofemoral pain (PFP) present kinematic alterations in proximal, local, and distal factors simultaneously, and determined the association between the number of kinematic alterations, pain level, and functional status. A three-dimensional motion analysis system was used to analyze the peak hip adduction, peak knee flexion, and peak rearfoot eversion, addressing the proximal, local, and distal factors, respectively, in fifty women. Functional status and pain level were assessed using the anterior knee pain scale (AKPS) and a visual analogic scale. Receiver operating characteristic curves were calculated to identify participants with and without kinematic alterations and the number of them was obtained for each participant. Associations between the number of kinematic alterations, pain level, and AKPS score were determined by the Pearson correlation. Results showed that 52% of women with PFP presented at least two kinematic alterations of which 24% were local/proximal, 16% local/distal, and 12% proximal/distal. Three kinematic alterations were found in 48% of the women with PFP. A strong positive correlation was found between the number of kinematic alterations and pain (r=0.78; p<0.001). A strong negative correlation was found between the number of altered kinematics and functional status (r=-0.79; p<0.001). Findings revealed that women with PFP presented at least two kinematic alterations and a higher number of kinematic alterations was associated with higher pain levels and lower functional status. Clinicians should carefully assess movement pattern of women with PFP as it could indicate a more severe condition, which is associated with a poor prognosis.


Subject(s)
Foot/physiopathology , Knee Joint/physiopathology , Pain Measurement/methods , Patellofemoral Pain Syndrome/physiopathology , Biomechanical Phenomena , Female , Humans , Patellofemoral Pain Syndrome/diagnosis , Pilot Projects , ROC Curve , Young Adult
7.
Rev. bras. med. esporte ; 22(4): 291-296, July-Aug. 2016. tab, graf
Article in Portuguese | LILACS | ID: lil-794858

ABSTRACT

RESUMO Introdução: Ajustes antecipatórios (pré-ativação) dos músculos profundos do tronco aumentam a estabilidade lombopélvica. Estudos prévios demonstram que indivíduos assintomáticos podem apresentar atrasos no início de ativação muscular e alterações físico-funcionais. No entanto, não foram encontrados estudos que tenham verificado se testes físico-funcionais (TFF) são capazes de identificar alteração no início de ativação dos músculos estabilizadores lombopélvicos. Objetivo : Verificar os níveis de sensibilidade, especificidade e acurácia de um conjunto de testes de avaliação da capacidade física funcional para detectar alterações na pré-ativação dos músculos transverso do abdome/oblíquo interno (TrA/OI) e multífido lombar (ML) durante o teste de movimento rápido de flexão do ombro (TMRFO). Método : Participaram do estudo 27 voluntários assintomáticos para dor lombar, com média de idade de 23,8 anos (desvio padrão: 2,2), e que foram submetidos aos TFF e TMRFO para determinação do início da ativação dos músculos profundos do tronco por meio da eletromiografia de superfície. Foi verificada sensibilidade e especificidade e análise da acurácia através da curva ROC (Receiver Operating Characteristic) e teste de qui-quadrado para comparações entre porcentagens (p < 0,05) . Resultados : A "pré-ativação" foi a condição que ocorreu com maior frequência no grupo como um todo, bem como em ambos os gêneros, com exceção do TrA/OI no gênero feminino (χ2 = 0,28/P = 0,58). Entre todos os TFF aplicados, o de enrolamento repetitivo do tronco apresentou maior valor de sensibilidade, especificidade e área sob a curva ROC (0,75; 0,73; 0,74, respectivamente) . Conclusão : Entre os TFF avaliados, o de enrolamento repetitivo do tronco mostrou níveis aceitáveis de acurácia para identificar alterações na ativação da musculatura estabilizadora lombopélvica em voluntários assintomáticos para dor lombar. Assim, o teste de enrolamento repetitivo do tronco pode ser utilizado na clínica para predizer alterações na ativação dos músculos profundos do tronco.


ABSTRACT Introduction: Anticipatory adjustments (pre-activation) of the deep trunk muscles increase lumbopelvic stability. Previous studies have shown that asymptomatic individuals may experience delays in the start of muscle activation, as well as functional physical alterations. However, there are no studies that assess whether physical and functional tests (PFT) are able to identify changes in early activation of the lumbopelvic stabilizer muscles. Objective: To assess the levels of sensitivity, specificity and accuracy of a set of physical and functional performance tests to detect changes in anticipatory activation of the transversus abdominis/internal oblique muscles (TrA/OI) and lumbar multifidus (ML) during a task of fast shoulder flexion movements (FSFM) . Method: Twenty-seven volunteers, asymptomatic for low back pain, with a mean age of 23.8 (Standard deviation: 2.2) years, participated in the study. They were submitted to PFT and FSFM to determine the initial activation time of the deep trunk muscles through surface electromyography. Sensitivity and specificity were determined, and accuracy was analyzed by the ROC (Receiver Operating Characteristic) curve and chi-square test for comparisons between percentages (p<0.05) . Results: Anticipatory activation was the condition that occurred most frequently in the group as a whole, and in both genders, with the exception of TrA/OI in females (χ2=0.28/P=0.58). Among all the PFT assessed, the repetitive trunk flexion-extension test showed the highest values for sensitivity, specificity and area under the ROC curve (0.75; 0.73; 0.74, respectively). Conclusion: Among the PFT evaluated, the repetitive trunk flexion-extension test showed acceptable levels of accuracy for identifying changes in the activation of deep trunk muscles in volunteers who were asymptomatic for low back pain. Thus, the repetitive trunk flexion-extension test can be used clinically to predict changes in the activation of deep muscles of the trunk.


RESUMEN Introducción: Ajustes de anticipación (pre-activación) de los músculos profundos del tronco aumentan la estabilidad lumbopélvica. Estudios anteriores demostraron que individuos asintomáticos (sin dolor) pueden presentar retrasos en el inicio de la activación muscular y alteraciones físicas y funcionales. Sin embargo, no fueron encontrados estudios que hayan verificado si las pruebas físicas y funcionales (PFF) son capaces de identificar los cambios en la activación temprana de los músculos estabilizadores lumbopélvicos. Objetivo: Verificar los niveles de sensibilidad, especificidad y exactitud de un conjunto de pruebas de evaluación de la capacidad física funcional para detectar cambios en la pre-activación de los músculos transverso abdominal/oblicuo interno (TrA/OI) y multífido lumbar (ML) durante la prueba de movimiento rápido de flexión del hombro (PMRFH) . Método: Participaron del estudio 27 voluntarios, asintomáticos para el dolor lumbar, con una edad media de 23,8 años (desviación estándar: 2,2), sometidos a PFF y PMRFH para determinar el inicio de la activación de los músculos profundos del tronco mediante electromiografía de superficie. Se encontró una sensibilidad y especificidad y análisis de exactitud a través de la curva ROC (Receiver Operating Characteristic) y la prueba de chi-cuadrado para las comparaciones entre porcentajes (p < 0,05). Resultados: La "pre-activación" fue la condición que ocurrió con más frecuencia en el grupo como un todo y en ambos sexos, con excepción de TrA/OI en las mujeres (χ2 = 0,28/P = 0,58). Entre todos los PFF aplicados, la flexión repetitiva del tronco presentó un mayor valor de sensibilidad, especificidad y el área bajo la curva ROC (0,75; 0,73; 0,74, respectivamente) . Conclusión: Entre los PFF evaluados, la flexión repetitiva del tronco mostró niveles aceptables de exactitud para identificar cambios en la activación de los músculos estabilizadores lumbopélvicos en voluntarios asintomáticos para dolor lumbar. Así, la prueba de flexión repetitiva del tronco se puede utilizar clínicamente para predecir cambios en la activación de los músculos profundos del tronco.

8.
Clin Biomech (Bristol, Avon) ; 30(2): 144-8, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25550186

ABSTRACT

BACKGROUND: Excessive rearfoot eversion is thought to be a risk factor for patellofemoral pain development, due to the kinesiological relationship with ascendant adaptations. Individuals with patellofemoral pain are often diagnosed through static clinical tests, in scientific studies and clinical practice. However, the adaptations seem to appear in dynamic conditions. Performing static vs. dynamic evaluations of widely used measures would add to the knowledge in this area. Thus, the aim of this study was to determine the reliability and differentiation capability of three rearfoot eversion measures: rearfoot range of motion, static clinical test and static measurement using a three-dimensional system. METHOD: A total of 29 individuals with patellofemoral pain and 25 control individuals (18-30 years) participated in this study. Each subject underwent three-dimensional motion analysis during stair climbing and static clinical tests. Intraclass correlation coefficient and standard error measurements were performed to verify the reliability of the variables and receiver operating characteristic curves to show the diagnostic accuracy of each variable. In addition, analyses of variance were performed to identify differences between groups. FINDINGS: Rearfoot range of motion demonstrated higher diagnostic accuracy (an area under the curve score of 0.72) than static measures and was able to differentiate the groups. Only the static clinical test presented poor and moderate reliability. Other variables presented high to very high values. INTERPRETATION: Rearfoot range of motion was the variable that presented the best results in terms of reliability and differentiation capability. Static variables do not seem to be related to patellofemoral pain and have low accuracy values.


Subject(s)
Foot/physiopathology , Patellofemoral Pain Syndrome/physiopathology , Adult , Biomechanical Phenomena , Female , Foot Joints/physiopathology , Humans , Movement , ROC Curve , Range of Motion, Articular , Reproducibility of Results , Young Adult
9.
Arch Phys Med Rehabil ; 95(8): 1521-6, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24742937

ABSTRACT

OBJECTIVE: To assess the diagnostic accuracy of the surface electromyography (sEMG) parameters associated with referred anterior knee pain in diagnosing patellofemoral pain syndrome (PFPS). DESIGN: Sensitivity and specificity analysis. SETTING: Physical rehabilitation center and laboratory of biomechanics and motor control. PARTICIPANTS: Pain-free subjects (n=29) and participants with PFPS (n=22) selected by convenience. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The diagnostic accuracy was calculated for sEMG parameters' reliability, precision, and ability to differentiate participants with and without PFPS. The selected sEMG parameter associated with anterior knee pain was considered as an index test and was compared with the reference standard for the diagnosis of PFPS. Intraclass correlation coefficient, SEM, independent t tests, sensitivity, specificity, negative and positive likelihood ratios, and negative and positive predictive values were used for the statistical analysis. RESULTS: The medium-frequency band (B2) parameter was reliable (intraclass correlation coefficient=.80-.90), precise (SEM=2.71-3.87 normalized unit), and able to differentiate participants with and without PFPS (P<.05). The association of B2 with anterior knee pain showed positive diagnostic accuracy values (specificity, .87; sensitivity, .70; negative likelihood ratio, .33; positive likelihood ratio, 5.63; negative predictive value, .72; and positive predictive value, .86). CONCLUSIONS: The results provide evidence to support the use of EMG signals (B2-frequency band of 45-96 Hz) of the vastus lateralis and vastus medialis muscles with referred anterior knee pain in the diagnosis of PFPS.


Subject(s)
Electromyography , Musculoskeletal Pain/physiopathology , Patellofemoral Pain Syndrome/diagnosis , Quadriceps Muscle/physiopathology , Adolescent , False Negative Reactions , False Positive Reactions , Female , Humans , Musculoskeletal Pain/etiology , Pain Measurement , Patellofemoral Joint , Patellofemoral Pain Syndrome/complications , Predictive Value of Tests , Prospective Studies , Signal Processing, Computer-Assisted , Young Adult
10.
Motriz rev. educ. fís. (Impr.) ; 20(2): 213-220, Apr-Jun/2014. tab, graf
Article in English | LILACS | ID: lil-715633

ABSTRACT

This study aimed to determine and analyze the neuromuscular fatigue onset by median frequency (MDF) and the root mean square (RMS) behavior of an electromyographic signal (EMG). Eighteen healthy men with no prior knee problems initially performed three maximum voluntary isometric contractions (MVIC). After two days of MVIC test, participants performed a fatiguing protocol in which they performed submaximal knee-extension contractions at 20% and 70% MVIC held to exhaustion. The MDF and RMS values from the EMG signals were recorded from the vastus medialis (VM) and the vastus lateralis (VL). Analysis of the MDF and RMS behavior enabled identification of neuromuscular fatigue onset for VM and VL muscles in 20% and 70% loads. Alterations between the VM and VL in the neuromuscular fatigue onset, at 20% and 70% MVIC, were not significant. These findings suggest that the methodology proposal was capable of indicating minute differences sensible to alterations in the EMG signals, allowing identification of the moment when the MDF and the RMS showed significant changes in behavior. The methodology used was also a viable one for describing and identifying the neuromuscular fatigue onset by means of the analysis of EMG signals...


Este estudo teve como objetivo determinar e analisar o início da fadiga neuromuscular pelo comportamento do sinal de eletromiográfico (EMG) da frequência mediana (FM) e do root mean square (RMS). Dezoito homens saudáveis, sem problemas no joelho, realizaram inicialmente três contrações isométricas voluntárias máximas (CVMs). Após dois dias de CVM os sujeitos realizaram um protocolo de fadiga em que realizaram contrações submáximas de extensão do joelho em 20% e 70% da CVM até a exaustão. Os valores dos sinais de FM e RMS foram registrados a partir do vasto medial (VM) e vasto lateral (VL). A análise do comportamento da FM e RMS permitiu a identificação do início da fadiga neuromuscular para os músculos VM e VL em 20% e 70% da carga máxima. Alterações entre o VM e VL no início da fadiga neuromuscular, com 20% e 70% do MVIC, não foram significativas. Estes resultados sugerem que a metodologia proposta foi capaz de indicar diferenças mínimas sensíveis a alterações nos sinais EMG, permitindo a identificação do momento em que a FM e o RMS apresentaram mudanças significativas no seu comportamento. A metodologia utilizada também foi viável para descrever e identificar o aparecimento da fadiga neuromuscular por meio de análise de sinais de EMG...


Este estudio tieve como objetivo determinar y analizar la aparición de fatiga neuromuscular por la frecuencia media (FM) y la media de la raíz cuadrada (RMS) de lo señal electromiográfico (EMG). Dieciocho hombres saludables que no tienen problemas de rodilla previas inicialmente realizaron tres contracciones máximas voluntarias (CVM). Después de dos días de CVM los sujetos realizaron un protocolo de fatiga en la que se presentaron submáximas de extensión de rodilla en 20% y el 70% CVM hasta el agotamiento. Los valores de FM y RMS de las señales EMG se registraron desde el vasto medial (VM) y el vasto lateral (VL). Análisis del comportamiento de FM y RMS activado identificación de inicio fatiga neuromuscular para VM y músculos VL y 20% y el 70 % de la carga maxima. Las alteraciones entre el VM y VL en el inicio de la fatiga neuromuscular, en el 20% y el 70% de la CVM, no fueron significativas. Estos hallazgos sugieren que la propuesta de metodología fue capaz de indicar las diferencias minutos sensibles a las alteraciones en las señales de EMG, que permitan identificar el momento en que el FM y el RMS mostraron cambios significativos en el comportamiento. La metodología utilizada fue también una opción viable para la descripción y la identificación de la aparición de fatiga neuromuscular por medio del análisis de las señales de EMG...


Subject(s)
Humans , Male , Adult , Muscle Fatigue/physiology , Isometric Contraction , Quadriceps Muscle/physiology , Electromyography/methods
11.
Mater Sci Eng C Mater Biol Appl ; 36: 226-36, 2014 Mar 01.
Article in English | MEDLINE | ID: mdl-24433908

ABSTRACT

The development of polymeric blends to be used as matrices for bone regeneration is a hot topic nowadays. In this article we report on the blends composed by corn starch and poly(vinylidene fluoride), PVDF, or poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE), to obtain biocompatible materials. Blends were produced by compressing/annealing and chemically/structurally characterized by micro-Raman scattering and Fourier transform infrared (FTIR) absorption spectroscopies, dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM), besides in vivo study to evaluate the tissue response. Vibrational spectroscopy reveals no chemical interaction between the polymers and starch, absence of material degradation due to compressing/annealing process or organism implantation, and maintenance of α and ferroelectric crystalline phases of PVDF and P(VDF-TrFE), respectively. As a consequence of absence of interaction between polymers and starch, it was possible to identify by SEM each material, with starch acting as filler. Elastic modulus (E') obtained from DMA measurement, independent of the material proportion used in blends, reaches values close to those of cancellous bone. Finally, the in vivo study in animals shows that the blends, regardless of the composition, were tolerated by cancellous bone.


Subject(s)
Biocompatible Materials/chemistry , Fluorocarbon Polymers/chemistry , Prostheses and Implants , Starch/chemistry , Zea mays/chemistry , Amylopectin/chemistry , Amylose/chemistry , Animals , Elastic Modulus , Male , Microscopy, Electron, Scanning , Rats , Rats, Wistar , Spectroscopy, Fourier Transform Infrared , Spectrum Analysis, Raman
13.
Motriz rev. educ. fís. (Impr.) ; 18(3): 456-464, jul.-set. 2012. tab
Article in Portuguese | LILACS | ID: lil-653574

ABSTRACT

O objetivo deste estudo foi analisar a reprodutibilidade de parâmetros no domínio da frequência do sinal eletromiográfico (EMG) utilizados na caracterização da fadiga muscular localizada. Quinze sujeitos do sexo masculino foram submetidos a um teste de fadiga baseado na extensão isométrica de joelho, sendo realizados em três momentos distintos com intervalos de sete dias. Para avaliar a reprodutibilidade dos dados entres os testes calculou-se o coeficiente de correlação intraclasse (CCI) para a frequência mediana (Fmed) no tempo total de exercício (FmedT), para a Fmed obtida a cada 10% do tempo de exercício (Fmed10%) e para as potências das bandas de frequência, obtidas da divisão do espectro de potência a cada 20 Hz. Os resultados demonstraram: (1) boa reprodutibilidade para a FmedT; (2) boa reprodutibilidade para a Fmed10%; e (3) maior variação no sinal EMG nas bandas de 20 a 120 Hz, no qual se destacam as bandas de 20-40 Hz e de 40-60 Hz, demonstrando maior sensibilidade ao processo de fadiga muscular. Conclui-se que a Fmed é uma variável que apresenta boa reprodutibilidade e que a análise fragmentada do espectro de potência, por meio das bandas de frequência, demonstrou-se sensível as variações que ocorrem no sinal EMG durante a instalação do processo de fadiga, tendo potencial para se tornar um novo método para a caracterização da fadiga muscular localizada.


The aim of this study was to analyze the reproducibility of the electromyography signal's parameters (EMG) in the frequency domain used in the characterization of localized muscle fatigue. Fifteen male subjects underwent a fatigue test based on isometric knee extension, being held at three different times at intervals of seven days. To assess the reproducibility of data between the tests we calculated the correlation coefficient (ICC) for the median frequency (MF) in total exercise time (MF T), MF obtained for every 10% of exercise time (MF10%) and the powers of the frequency bands obtained by dividing the power spectrum at windows of 20 Hz. The results showed: (1) excellent reproducibility for MF T, (2) good reproducibility for MF10%, and (3) greater variation in the signal EMG bands from 20 to 120 Hz, especially at the bands of 20-40 Hz and 40-60 Hz, which showed greater sensitivity to the process of muscle fatigue. We conclude that the MF is a variable that shows good reproducibility and that the fragmented analysis of the power spectrum, by means of frequency bands, showed that significant variations occur in the EMG signal during the installation of the fatigue process, having potential to become a new method for the characterization of localized muscle fatigue.


Subject(s)
Humans , Male , Adult , Biomechanical Phenomena , Muscle Fatigue/physiology , Quadriceps Muscle/physiology , Electromyography/methods , Reproducibility of Results
15.
J Electromyogr Kinesiol ; 21(6): 982-7, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21889361

ABSTRACT

To understand patellofemoral pain syndrome (PFPS), recent studies have focused on assessing the onset in the vastus medialis and vastus lateralis to determine whether there is a delay between these muscles' activation. However, the results of these studies are not in agreement, as some research shows that there is a delay in the VMO, while others do not show delay. It has been suggested that this discrepancies may be due to differences in the signal processing and analysis. For this reason, this study aimed to compare the three techniques used for onset determination - automatic detection, visual inspection and cross-correlation - and to verify whether these methods are able to detect PFPS. The surface electromyography evaluation procedure was conducted in 22 pain-free control individuals and 11 with PFPS diagnoses, during a stair climbing. The standard error of measurement (SEM) showed that cross-correlation presents the lower variation (2.56/3.27, control/PFPS) in relation to visual (3.77/10.19, control/PFPS) and automatic detection (43.23/51.98, control/PFPS, respectively). But when using the cross-correlation technique, we were not able to distinguish the groups (-6.56/-9.74ms, control/PFPS, p=0.15). Therefore, use of muscle onset may not be the best way to distinguish individuals with PFPS.


Subject(s)
Algorithms , Electromyography/methods , Muscle Contraction , Muscle, Skeletal/physiopathology , Patellofemoral Pain Syndrome/diagnosis , Patellofemoral Pain Syndrome/physiopathology , Adult , Diagnosis, Computer-Assisted , Female , Humans , Reproducibility of Results , Sensitivity and Specificity
16.
Biomacromolecules ; 12(9): 3223-31, 2011 Sep 12.
Article in English | MEDLINE | ID: mdl-21766835

ABSTRACT

The concern related to the environmental degradation and to the exhaustion of natural resources has induced the research on biodegradable materials obtained from renewable sources, which involves fundamental properties and general application. In this context, we have fabricated thin films of lignins, which were extracted from sugar cane bagasse via modified organosolv process using ethanol as organic solvent. The films were made using the vacuum thermal evaporation technique (PVD, physical vapor deposition) grown up to 120 nm. The main objective was to explore basic properties such as electrical and surface morphology and the sensing performance of these lignins as transducers. The PVD film growth was monitored via ultraviolet-visible (UV-vis) absorption spectroscopy and quartz crystal microbalance, revealing a linear relationship between absorbance and film thickness. The 120 nm lignin PVD film morphology presented small aggregates spread all over the film surface on the nanometer scale (atomic force microscopy, AFM) and homogeneous on the micrometer scale (optical microscopy). The PVD films were deposited onto Au interdigitated electrode (IDE) for both electrical characterization and sensing experiments. In the case of electrical characterization, current versus voltage (I vs V) dc measurements were carried out for the Au IDE coated with 120 nm lignin PVD film, leading to a conductivity of 3.6 × 10(-10) S/m. Using impedance spectroscopy, also for the Au IDE coated with the 120 nm lignin PVD film, dielectric constant of 8.0, tan δ of 3.9 × 10(-3), and conductivity of 1.75 × 10(-9) S/m were calculated at 1 kHz. As a proof-of-principle, the application of these lignins as transducers in sensing devices was monitored by both impedance spectroscopy (capacitance vs frequency) and I versus time dc measurements toward aniline vapor (saturated atmosphere). The electrical responses showed that the sensing units are sensible to aniline vapor with the process being reversible. AFM images conducted directly onto the sensing units (Au IDE coated with 120 nm lignin PVD film) before and after the sensing experiments showed a decrease in the PVD film roughness from 5.8 to 3.2 nm after exposing to aniline.


Subject(s)
Biosensing Techniques , Chemistry Techniques, Analytical , Lignin/chemistry , Saccharum/chemistry , Aniline Compounds/analysis , Cellulose/chemistry , Dielectric Spectroscopy , Electric Conductivity , Electrodes , Gases , Gold/chemistry , Membranes, Artificial , Microscopy, Atomic Force , Quartz Crystal Microbalance Techniques , Surface Properties , Transducers
17.
Braz. j. phys. ther. (Impr.) ; 14(6): 477-482, nov.-dez. 2010. tab
Article in Portuguese | LILACS | ID: lil-574779

ABSTRACT

CONTEXTUALIZAÇÃO: O uso da eletromiografia de superfície (EMG-S) tem sido considerado como instrumento de avaliação quantitativa na síndrome da dor patelofemoral (SDPF). Tratamentos conservadores objetivam melhorar o alinhamento patelar, e a estimulação elétrica do músculo vasto medial oblíquo (VMO) tem sido considerada por ser seletiva e não causar irritação articular. OBJETIVO: Verificar o efeito de um programa de fortalecimento muscular com estimulação elétrica do VMO na SDPF por meio da capacidade de avaliação da EMG-S. MÉTODOS: Participaram deste estudo 10 mulheres jovens (idade: 23,1±4,9 anos; massa corporal: 66,8±14,0 kg; estatura: 1,63±6,9 cm; IMC: 25,1±5,6 kg/m²) com SDPF unilateral, as quais realizaram o teste funcional de subir degrau para captação da atividade eletromiográfica dos músculos VMO e vasto lateral (VL), antes e após um programa de estimulação elétrica do VMO. A eletroestimulação foi realizada três vezes por semana, durante seis semanas. Foram consideradas, para análise entre VMO e VL, as variáveis razão do tempo do início até o pico de ativação, razão da integral do sinal (teste t para amostras dependentes) e diferença de início de ativação (teste de Wilcoxon), com nível de significância de p<0,05. RESULTADOS: Os resultados mostraram que ocorreu alteração somente no comportamento eletromiográfico relativo à razão da integral do sinal, mostrando que, após o treinamento muscular, ocorreram mudanças na capacidade de geração da força. CONCLUSÃO: O uso da eletroestimulação deve ser considerado no sentido de complementar a abordagem terapêutica conservadora em portadores da SDFP e a análise da razão da integral do sinal de EMG-S, como instrumento de avaliação. Artigo registrado no Australian New Zealand Clinical Trials Registry (ANZCTR) sob o número ACTRN 12609000079246.


BACKGROUND: The use of surface electromyography (SEMG) has been considered a tool for quantitative assessment of patellofemoral pain syndrome (PFPS). Conservative treatments aim to improve patellar alignment, and electrical stimulation of the vastus medialis obliquus (VMO) muscle has been considered effective because it is selective and does not cause joint irritation. OBJECTIVE: This study aims to investigate the efficiency of a muscle strengthening program with electrical stimulation of the VMO muscle in PFPS by SEMG. METHODS: A group of ten young women (age: 23.1±4.9 years; body mass: 66.8±14.0 kg; height: 1.63±6.9 cm; BMI: 25.1±5.6 kg/m²) with unilateral PFPS participated in the study. They performed the functional test of stair stepping to capture the electromyographic (EMG) activity of the VMO and vastus lateralis (VL) muscles, before and after a program of electrical stimulation of the VMO muscle. The electrical stimulation was performed three times per week for six weeks. For analysis between the VMO and VL muscles, we considered the variables: ratio of time of onset to peak of activation, ratio of the integrals of the signals (t-test for dependent samples), and difference between onsets of activation (Wilcoxon test), with significance level of p<0.05. RESULTS: The results only showed change in behavior in the EMG signal for the ratio of the integrals of the signals, indicating that changes occurred in the force-generating capacity of the muscle after the training. CONCLUSION: The use of electrical stimulation should be considered to complement the conservative therapeutic approach in patients with PFPS, and the analysis of the ratio of the integrals of the SEMG signals should be considered as an instrument of evaluation. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under number ACTRN 12609000079246.


Subject(s)
Female , Humans , Young Adult , Patellofemoral Pain Syndrome/therapy , Transcutaneous Electric Nerve Stimulation , Muscle Strength , Muscle, Skeletal , Patellofemoral Pain Syndrome/physiopathology
18.
Arq Neuropsiquiatr ; 68(4): 562-6, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20730310

ABSTRACT

Many authors have studied physical and functional changes in individuals post-stroke, but there are few studies that assess changes in the non-plegic side of hemiplegic subjects. This study aimed to compare the electromyographic activity in the forearm muscles of spastic patients and clinically healthy individuals, to determine if there is difference between the non-plegic side of hemiplegics and the dominant member of normal individuals. 22 hemiplegic subjects and 15 clinically healthy subjects were submitted to electromyography of the flexor and extensor carpi ulnaris muscles during wrist flexion and extension. The flexor muscles activation of stroke group (average 464.6 u.n) was significantly higher than the same muscles in control group (mean: 106.3 u.n.) during the wrist flexion, what shows that the non affected side does not present activation in the standard of normality found in the control group.


Subject(s)
Electromyography/methods , Forearm/physiology , Hemiplegia/physiopathology , Muscle Contraction/physiology , Muscle Spasticity/physiopathology , Muscle, Skeletal/physiopathology , Case-Control Studies , Female , Hemiplegia/etiology , Humans , Male , Middle Aged , Stroke/complications
19.
Arq. neuropsiquiatr ; 68(4): 562-566, Aug. 2010. ilus, tab
Article in English | LILACS | ID: lil-555235

ABSTRACT

Many authors have studied physical and functional changes in individuals post-stroke, but there are few studies that assess changes in the non-plegic side of hemiplegic subjects. This study aimed to compare the electromyographic activity in the forearm muscles of spastic patients and clinically healthy individuals, to determine if there is difference between the non-plegic side of hemiplegics and the dominant member of normal individuals. 22 hemiplegic subjects and 15 clinically healthy subjects were submitted to electromyography of the flexor and extensor carpi ulnaris muscles during wrist flexion and extension. The flexor muscles activation of stroke group (average 464.6 u.n) was significantly higher than the same muscles in control group (mean: 106.3 u.n.) during the wrist flexion, what shows that the non affected side does not present activation in the standart of normality found in the control group.


Muitos autores estudaram as modificações funcionais e físicas em indivíduos pós-acidente vascular cerebral; porém, poucos estudos avaliam alterações no hemicorpo não plégico de indivíduos hemiplégicos. O objetivo deste estudo foi comparar a atividade eletromiográfica nos músculos do antebraço de pacientes espásticos e indivíduos clinicamente saudáveis, para averiguar se há diferença entre o lado não plégico de indivíduos hemiplégicos e o lado dominante de indivíduos clinicamente saudáveis. 22 indivíduos hemiplégicos e 15 clinicamente saudáveis foram submetidos à eletromiografia dos músculos flexor e extensor ulnar do carpo durante a flexão e extensão do punho. A ativação dos músculos flexores dos hemiplégicos (média: 464,6 u.n), foi significantemente maior que nos indivíduos do grupo controle (média: 106,3 u.n) durante o movimento de flexão do punho, o que demonstra que o hemicorpo não acometido dos pacientes estudados não apresenta o comportamento padrão de normalidade encontrado no grupo controle.


Subject(s)
Female , Humans , Male , Middle Aged , Electromyography/methods , Forearm/physiology , Hemiplegia/physiopathology , Muscle Contraction/physiology , Muscle Spasticity/physiopathology , Muscle, Skeletal/physiopathology , Case-Control Studies , Hemiplegia/etiology , Stroke/complications
20.
Rev Bras Fisioter ; 14(6): 477-82, 2010.
Article in English, Portuguese | MEDLINE | ID: mdl-21340241

ABSTRACT

BACKGROUND: The use of surface electromyography (SEMG) has been considered a tool for quantitative assessment of patellofemoral pain syndrome (PFPS). Conservative treatments aim to improve patellar alignment, and electrical stimulation of the vastus medialis obliquus (VMO) muscle has been considered effective because it is selective and does not cause joint irritation. OBJECTIVE: This study aims to investigate the efficiency of a muscle strengthening program with electrical stimulation of the VMO muscle in PFPS by SEMG. METHODS: A group of ten young women (age: 23.1 ± 4.9 years; body mass: 66.8 ± 14.0 kg; height: 1.63 ± 6.9 cm; BMI: 25.1 ± 5.6 kg/m²) with unilateral PFPS participated in the study. They performed the functional test of stair stepping to capture the electromyographic (EMG) activity of the VMO and vastus lateralis (VL) muscles, before and after a program of electrical stimulation of the VMO muscle. The electrical stimulation was performed three times per week for six weeks. For analysis between the VMO and VL muscles, we considered the variables: ratio of time of onset to peak of activation, ratio of the integrals of the signals (t-test for dependent samples), and difference between onsets of activation (Wilcoxon test), with significance level of p < 0.05. RESULTS: The results only showed change in behavior in the EMG signal for the ratio of the integrals of the signals, indicating that changes occurred in the force-generating capacity of the muscle after the training. CONCLUSION: The use of electrical stimulation should be considered to complement the conservative therapeutic approach in patients with PFPS, and the analysis of the ratio of the integrals of the SEMG signals should be considered as an instrument of evaluation. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under number ACTRN 12609000079246.


Subject(s)
Patellofemoral Pain Syndrome/therapy , Transcutaneous Electric Nerve Stimulation , Female , Humans , Muscle Strength , Muscle, Skeletal , Patellofemoral Pain Syndrome/physiopathology , Young Adult
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