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1.
RSC Adv ; 13(9): 5813-5825, 2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36816063

RESUMO

Dicalcium phosphate dihydrate (CaHPO4·2H2O, DCPD, brushite) crystals were synthesised within Scots pine sapwood via a wet-chemistry route from aqueous solutions of Ca(CH3COO)2 and NH4H2PO4 salts. SEM/EDS analysis was used to assess the saturation of the wood cell lumina and cell wall as well as morphological features and elemental composition of the co-precipitated mineral. Brushite mineral crystallization and crystallite growth within the wood matrix was studied by in situ XRD. The chemical composition of the mineral before and after the dissolution was evaluated using FTIR spectroscopy. The overall impact of brushite on the thermal behaviour of wood was studied by TGA/DSC and TGA/DTA/MS analysis under oxidative and pyrolytic conditions. Bending and compression strength perpendicular and parallel to the fibre directions as well as bending strengths in longitudinal and transverse directions of the mineralised wood were also evaluated. Results indicate the viability of the wet-chemistry processing route for wood reinforcement with crystalline calcium phosphate (CaP)-based minerals, and imply a potential in producing hybrid bio-based materials that could be attractive in the construction sector as an environmentally friendly building material.

2.
Front Chem ; 10: 1048313, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36465870

RESUMO

This work describes the main advances carried out in the field of corrosion protection using layered double hydroxides (LDH), both as additive/pigment-based systems in organic coatings and as conversion films/pre-treatments. In the context of the research topic "Celebrating 20 years of CICECO", the main works reported herein are based on SECOP's group (CICECO) main advances over the years. More specifically, this review describes structure and properties of LDH, delving into the corrosion field with description of pioneering works, use of LDH as additives to organic coatings, conversion layers, application in reinforced concrete and corrosion detection, and environmental impact of these materials. Moreover, the use of computational tools for the design of LDH materials and understanding of ion-exchange reactions is also presented. The review ends with a critical analysis of the field and future perspectives on the use of LDH for corrosion protection. From the work carried out LDH seem very tenable, versatile, and advantageous for corrosion protection applications, although several obstacles will have to be overcome before their use become commonplace.

3.
Sensors (Basel) ; 22(14)2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-35891035

RESUMO

The sulfuric acid attack is a common form of degradation of reinforced concrete in contact with industrial wastewater, mine water, acid rain, or in sewage treatment stations. In this work, new pH-sensitive IrOx electrodes were developed for monitoring the pH inside mortar or concrete. To test their ability, the pH sensors were embedded in mortar samples at different depths and the samples were exposed to sulfuric acid solution. In another set of experiments, iron wires were placed at the same depths inside similar mortar samples and their corrosion was monitored as the acid attacked the mortar. Severe acid attack led to cement dissolution and formation of gypsum. The new pH sensors succeeded in measuring the pH changes inside the mortars. The pH gradient, from the high acid environment to the high alkaline mortar interior, occurred in a narrow region. Corrosion of the iron electrodes started only when the acidic solution was in their close vicinity.


Assuntos
Materiais de Construção , Aço , Corrosão , Concentração de Íons de Hidrogênio , Ferro , Ácidos Sulfúricos
4.
Int J Mol Sci ; 23(14)2022 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-35886956

RESUMO

An efficient synthetic access to new cationic porphyrin-bipyridine iridium(III) bis-cyclometalated complexes was developed. These porphyrins bearing arylbipyridine moieties at ß-pyrrolic positions coordinated with iridium(III), and the corresponding Zn(II) porphyrin complexes were spectroscopically, electrochemically, and electronically characterized. The features displayed by the new cyclometalated porphyrin-bipyridine iridium(III) complexes, namely photoinduced electron transfer process (PET), and a remarkable efficiency to generate 1O2, allowing us to envisage new challenges and opportunities for their applications in several fields, such as photo(catalysis) and photodynamic therapies.


Assuntos
Irídio , Porfirinas , Cátions , Transporte de Elétrons , Irídio/química , Ligantes
5.
Materials (Basel) ; 14(4)2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33572165

RESUMO

Molybdenum oxide thin films were deposited on stiff and flexible substrates by reactive DC magnetron sputtering. Two sets of samples were prepared. The first with different O2/Ar flow rate ratios and the second, fixing the oxygen content, with different time of deposition. As the O2/Ar flow rate ratio varies from 0 up to 0.56, a threshold was found, ranging from crystalline to amorphous nature, and from a nontransparent appearance with metallic-like electrical conductivity to transparent and dielectric behaviour. From the second set, all transparent, the MoOx films present a compact/dense and featureless morphology with thickness from 190 up to 910 nm, depending on the time of deposition. Their structure was corroborated by XPS and Rutherford Backscattering Spectrometry (RBS) and density measurements were performed by RBS and X-ray reflectivity (XRR), revealing a value of 2.4 g/cm3. The surface roughness is in the order of a few nanometers and the maxima optical transmission, in the visible range, is around 89%. Electrochemical cyclic voltammograms showed noticeable color reversibility and reproducibility on the flexible substrates opening new framework possibilities for new electrochomic devices.

6.
J Environ Manage ; 272: 111080, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32854886

RESUMO

Reclaiming water for cooling systems in oil refineries has been strongly encouraged over the past years for decreasing the large consumption of fresh water, thus contributing to the efficient use of this valuable resource. In a recent study [Journal of Environmental Management 261 (2020) 110229], some of the authors studied the retention of phenols in refinery wastewater through reverse osmosis (RO) and found rejections of up to 98% of phenols and 99% of both chemical oxygen demand (COD) and total organic carbon (TOC). The permeates complied with the quality standards for make-up water in cooling processes. A missing aspect, important for the water to be used in the oil and gas industry, was the level of corrosivity of the new permeates. In this work the corrosion of mild carbon steel in the permeates and in the original cooling tower make-up water was studied by electrochemical techniques. The corrosion rate of steel in the permeates in aerated conditions was lower (between 0.053 ± 0.006 and 0.123 ± 0.011 mm year-1) than in the make-up water (0.167 ± 0.030 mm year-1), confirming their suitability for replacing make-up water in the cooling towers. The low corrosion of carbon steel was attributed to the low conductivity and absence of oxidizing species in the fluids, compared to fresh water.


Assuntos
Carbono , Aço , Corrosão , Eliminação de Resíduos Líquidos , Água
7.
Materials (Basel) ; 13(7)2020 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-32283861

RESUMO

This work investigated the use of ZnAl-layered double hydroxide (LDH) intercalated with nitrate or nitrite ions for controlling the corrosion of steel in reinforced concrete. The work started by analyzing the stability of the powder in the 1-14 pH range and the capacity for capturing chloride ions in aqueous solutions of different pH. The effect of the ZnAl-LDH on the corrosion of steel was studied in aqueous 0.05 M NaCl solution and in mortars immersed in 3.5% NaCl. It was found that the LDH powders dissolved partially at pH > 12. The LDH was able to capture chloride ions from the external solution, but the process was pH-dependent and stopped at high pH due to the partial dissolution of LDH and the preferential exchange of OH- ions. These results seemed to imply that ZnAl-LDH would not work in the alkaline environment inside the concrete. Nonetheless, preliminary results with mortars containing ZnAl-LDH showed lower penetration of chloride ions and higher corrosion resistance of the steel rebars.

8.
Materials (Basel) ; 13(6)2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32245066

RESUMO

The issue of chloride induced corrosion of reinforced concrete is a serious problem affecting infrastructure globally and causing huge economic losses. As such this issue has gained a considerable attention in the scientific community in the recent past. Layered Double Hydroxides (LDHs) have recently emerged as a new class of concrete-additives with a potential to increase the chloride resistance of concrete and mitigate corrosion. LDHs are clay like structures consisting of positively charged layers of cations with associated hydroxides and exchangeable anions in between the layers. Due to this charge balanced structure, LDHs possess the property of encapsulating an anion from the environment and replacing it with an exchangeable anion present in its layers. Potential applications include chloride entrapment in concrete and delivery of corrosion inhibiting anions. However, many versatile compositions of LDHs can be easily synthesized and their application as cement additives reach far beyond corrosion mitigation in concrete. This review presents a summary of recent advances on the applications of LDH in concrete. An extensive set of recently published literature has been critically reviewed and trends have been identified.

9.
Motrivivência (Florianópolis) ; 30(55): 156-176, Set. 2018.
Artigo em Português | LILACS | ID: biblio-965457

RESUMO

O objetivo deste artigo foi problematizar a caracterização dos esportes de aventura a partir do caso da equipe de rafting Bozo D'água, um contraexemplo em relação à literatura pioneira sobre o tema. Parte de etnografia mais ampla, o presente texto analisa dez entrevistas cotejadas com observação de campo. Os resultados indicam que, ao contrário da prática de aventura caracterizada como participação não competitiva de lazer, o esporte de alto rendimento foi a alternativa para viabilizar a participação esportiva em atividade de aventura para praticantes de classes sociais baixas. Conclui-se que diferentes formas de apropriação e distintas versões do esporte de aventura variam conforme contexto e questões de classe e que o potencial das práticas de aventura, de colocar em circulação valores esportivos alternativos, perde espaço na medida em que as políticas públicas brasileiras priorizam o esporte de alto rendimento.


This paper´s objective was to analyse the characterization of adventure sports though the analysis of the practice conditions of the Brazilian rafting team called Bozo D´água, a counterexample regarding the literature review. Part of an ethnography, it is focused on ten in depth interviews and field observation. The results indicate that, on the contrary of the adventure practice described as leisure participation, high performance sport was the only possibility of adventure participation for those athletes. Concluding that different versions of adventure sports vary according to class issues, and the potential for circulating alternative sportive values of the adventure practices lose space as Brazilian public politics prioritize high performance sports.


El objetivo de este artículo fue problematizar la caracterización de los deportes de aventura a partir del caso del equipo de rafting Bozo de agua, un contraejemplo en relación a la revisión de literatura. Parte de una etnografía más amplia, se centra en diez entrevistas en profundidad cotejándolas con la observación de campo. Los resultados indican que, diferentemente de la práctica de aventura caracterizada como participación no competitiva de ocio, el deporte de alto rendimiento fue la alternativa para viabilizar la participación en actividad de aventura para practicantes de clases bajas. Se concluye que diferentes formas de apropiación y distintas versiones de los deportes de aventura varían según contexto y cuestiones de clase y que el potencial de las prácticas de aventura de poner en circulación valores deportivos alternativos pierde espacio en la medida en que las políticas públicas brasileñas priorizan el deporte De alto rendimiento.


Assuntos
Natureza , Atletas , Esportes Aquáticos , Atividades de Lazer
10.
ACS Appl Mater Interfaces ; 9(28): 24282-24289, 2017 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-28654237

RESUMO

Energy-transfer reactions are the key for living open systems, biological chemical networking, and the development of life-inspired nanoscale machineries. It is a challenge to find simple reliable synthetic chemical networks providing a localization of the time-dependent flux of matter. In this paper, we look to photocatalytic reaction on TiO2 from different angles, focusing on proton generation and introducing a reliable, minimal-reagent-consuming, stable inorganic light-promoted proton pump. Localized illumination was applied to a TiO2 surface in solution for reversible spatially controlled "inorganic photoproton" isometric cycling, the lateral separation of water-splitting reactions. The proton flux is pumped during the irradiation of the surface of TiO2 and dynamically maintained at the irradiated surface area in the absence of any membrane or predetermined material structure. Moreover, we spatially predetermine a transient acidic pH value on the TiO2 surface in the irradiated area with the feedback-driven generation of a base as deactivator. Importantly we describe how to effectively monitor the spatial localization of the process by the in situ scanning ion-selective electrode technique (SIET) measurements for pH and the scanning vibrating electrode technique (SVET) for local photoelectrochemical studies without additional pH-sensitive dye markers. This work shows the great potential for time- and space-resolved water-splitting reactions for following the investigation of pH-stimulated processes in open systems with their flexible localization on a surface.

11.
J Colloid Interface Sci ; 468: 86-94, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-26828278

RESUMO

Zinc-aluminum layered double hydroxides with nitrate intercalated (Zn(n)Al-NO3, n=Zn/Al) is an intermediate material for the intercalation of different functional molecules used in a wide range of industrial applications. The synthesis of Zn(2)Al-NO3 was investigated considering the time and temperature of hydrothermal treatment. By examining the crystallite size in two different directions, hydrodynamic particle size, morphology, crystal structure and chemical species in solution, it was possible to understand the crystallization and dissolution processes involved in the mechanisms of crystallite and particle growth. In addition, hydrogeochemical modeling rendered insights on the speciation of different metal cations in solution. Therefore, this tool can be a promising solution to model and optimize the synthesis of layered double hydroxide-based materials for industrial applications.

12.
J Mater Chem B ; 3(9): 1831-1845, 2015 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-32262256

RESUMO

Biomaterials can still be reinvented to become simple and universal bone regeneration solutions. Following this roadmap, conductive CNT-based "smart" materials accumulate exciting grafting qualities for tuning the in vitro cellular phenotype. Biphasic electrical stimulation of human osteoblastic cells was performed in vitro on either dielectric bioactive bone grafts or conductive CNT-reinforced composites. The efficiency of the electrical stimuli delivery, as well as the effect of stimulation on cellular functions were investigated. Conductive substrates boosted the local culture medium conductivity and the confinement of the exogenous electrical fields. Hence, bone cell proliferation, DNA content and mRNA expression were maximized on the conductive substrates yielding superior stimuli delivering efficiency over dielectric ones. These findings are suggestive that bioactive bone grafts with electrical conductivity are capable of high spatial and temporal control of bone cell stimulation.

13.
Nanotechnology ; 25(36): 365701, 2014 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-25141030

RESUMO

Metallic implants and devices are widely used in the orthopedic and orthodontic clinical areas. However, several problems regarding their adhesion with the living tissues and inflammatory responses due to the release of metallic ions to the medium have been reported. The modification of the metallic surfaces and the use of biocompatible protective coatings are two approaches to solve such issues. In this study, in order to improve the adhesion properties and to increase the corrosion resistance of metallic Ti substrates we have obtained a hybrid structure based on TiO2 nanotubular arrays and PDMS-TEOS films. TiO2 nanotubes have been prepared with two different diameters by means of electrochemical anodization. PDMS-TEOS films have been prepared by the sol-gel method. The morphological and the elemental analysis of the structures have been investigated by scanning electron microscopy and energy dispersive spectroscopy (EDS). Electrochemical impedance spectroscopy (EIS) and polarization curves have been performed during immersion of the samples in Kokubo's simulated body fluid (SBF) at 37 °C to study the effect of structure layers and tube diameter on the protective properties. The obtained results show that the modification of the surface structure of TiO2 and the application of PDMS-TEOS film is a promising strategy for the development of implant materials.


Assuntos
Materiais Revestidos Biocompatíveis/síntese química , Dimetilpolisiloxanos/química , Nanotubos/química , Nylons/química , Silanos/química , Titânio/química , Eletroquímica , Humanos , Teste de Materiais , Nanotubos/ultraestrutura
15.
Epilepsy Behav ; 25(2): 208-13, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23032134

RESUMO

PURPOSE: The identification of variables associated with health-related quality of life (HRQoL) in patients with mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) would improve surgical decision-making and post-operatory follow-up in this group of patients. METHODS: We analyzed the independent association between the Quality of Life in Epilepsy Inventory-31 (QOLIE-31) of 81 consecutive patients with refractory MTLE-HS. The clinical, demographic, radiological and electrophysiological variables were analyzed by multiple linear regression analysis. KEY FINDINGS: Approximately 36% (adjusted R(2)=0.36; R coefficient=0.66) of the QOLIE-31 overall score variance was explained by the history of initial precipitant injury, family history of epilepsy, disease duration, age of epilepsy onset, seizure frequency and presence of psychiatric axis-II diagnosis. The variance of QOLIE-31 sub-scales was: seizure worry=7%; overall QOL=11%; emotional well-being=32%; energy/fatigue=38%; cognitive function=13%; medication effects=7%; social function=13% (R coefficient between 0.30 and 0.65). SIGNIFICANCE: The pre-surgical variables studied had relatively low prediction capacity for the overall QOLIE-31 score and its sub-scales in this set of Brazilian patients with refractory MTLE-HS.


Assuntos
Epilepsia do Lobo Temporal/psicologia , Hipocampo/patologia , Qualidade de Vida/psicologia , Adulto , Epilepsia do Lobo Temporal/patologia , Epilepsia do Lobo Temporal/cirurgia , Feminino , Nível de Saúde , Hipocampo/cirurgia , Humanos , Masculino , Esclerose , Índice de Gravidade de Doença , Inquéritos e Questionários , Resultado do Tratamento
16.
Seizure ; 20(6): 480-4, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21439855

RESUMO

PURPOSE: To investigate the frequency and patterns of headache in a well-defined and homogeneous group of mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) patients. METHODS: One hundred consecutive MTLE-HS patients under comprehensive presurgical evaluation were evaluated from May 2009 to April 2010. A standardized questionnaire was applied according to the criteria of the International Headache Society (IHS). Headache diagnosis was based on the second edition of the International Classification of Headache Disorders (ICHD-II). RESULTS: Ninety-two patients (92%) had at least one headache episode during the previous 12 months. Migraine occurred in 51.9% of patients and tension-type headache (TTH) in 39.1%. Patients with migraine presented higher frequency (p=0.002) and severity of episodes (p<0.001), as well as lateralized pain (p=0.001) than individuals with TTH. MTLE-HS patients with unilateral HS and predominantly unilateral headache (irrespective of the type), presented pain ipsilateral to the HS (OR 8.5; CI 95%=2.1-35.1; p=0.003). CONCLUSIONS: Headache is a frequent clinical symptom of lateralizing value, which may share common pathophysiology with epileptogenesis among MTLE-HS patients.


Assuntos
Epilepsia do Lobo Temporal/patologia , Cefaleia/etiologia , Hipocampo/patologia , Adulto , Idade de Início , Anticonvulsivantes/uso terapêutico , Estudos Transversais , Escolaridade , Eletroencefalografia , Epilepsia do Lobo Temporal/complicações , Epilepsia do Lobo Temporal/fisiopatologia , Epilepsia do Lobo Temporal/terapia , Feminino , Lateralidade Funcional , Cefaleia/fisiopatologia , Hipocampo/fisiopatologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos , Esclerose , Fatores Socioeconômicos , Ácido Valproico/uso terapêutico
17.
Braz. arch. biol. technol ; 51(1): 49-56, Jan.-Feb. 2008. tab
Artigo em Inglês | LILACS | ID: lil-482053

RESUMO

A trial was carried out to determine the lysine requirement for starting barrows fed on ideal protein concept-based diets. Thirty-two pigs from a commercial crossbred genetic group (CCGG, BW=15.9 ± 1.4 kg) and 32 pigs from a dam line one (DLGG, BW= 14.8 ± 1.0 kg) were used. Pigs were allotted to 4 treatments with diets containing increasing levels of total lysine (0.80, 1.00, 1.20 and 1.40 percent). Methionine+cystine, threonine and tryptophan were adjusted according to ideal protein profile. Data from performance, plasma urea nitrogen (PUN) and carcass composition were analyzed. CCGG showed higher daily feed intake, daily weight gain, PUN and protein:fat ratio in carcass, while DLGG showed higher fat carcass content and nitrogen retention. Fat content and protein:fat ratio in carcass for CCCGG and PUN and crude protein carcass content for DLGG showed quadratic response to increasing total lysine levels. Derivations of the quadratic equations indicated the total lysine requirement for CCGG starting barrows is 1.15 percent and for DLGG starting barrows is 1.09 percent.


Foi realizado um trabalho com o objetivo de determinar a exigência em lisina para suínos castrados em fase inicial, alimentados com dietas formuladas de acordo com o conceito de proteína ideal. Trinta e dois suínos provenientes de cruzamento comercial (CC, PV = 15,9 kg) e 32 suínos provenientes de linhagem materna (LM, PV= 14,8 kg) foram alimentados com quatro dietas contendo níveis crescentes de lisina total (0,80; 1,00; 1,20 e 1,40 por cento). Metionina + cistina, triptofano e treonina foram adicionados às dietas para manter constante o padrão de proteína ideal. Foram analisados dados de desempenho, nitrogênio da uréia plasmática (NUP) e carcaça. Suínos do grupo CC apresentaram maior consumo diário de ração, ganho diário de peso, NUP e relação proteína: gordura na carcaça, enquanto que os animais do grupo LM apresentaram maiores teores de gordura na carcaça e retenção de nitrogênio. Teor de gordura e relação proteína:gordura na carcaça para o grupo CC e NUP e teor de proteína bruta na carcaça para o grupo LM apresentaram resposta quadrática aos níveis de lisina. Derivações das equações indicaram a exigência de lisina total de suínos machos castrados do grupo cruzamento industrial de 1,15 por cento e do grupo linhagem materna de 1,09 por cento.

18.
Ciênc. rural ; 37(2): 495-501, mar.-abr. 2007. tab
Artigo em Português | LILACS | ID: lil-444024

RESUMO

Um experimento de desempenho foi conduzido com o objetivo de avaliar a viabilidade nutricional e econômica da utilização de rações com diferentes tipos de milheto, com nível de inclusão de 60 por cento, na alimentação de suínos, nas fases de crescimento e terminação. Foram utilizados 40 suínos híbridos na fase de crescimento (30,3±2,9kg) e terminação (54,3±4,1kg), distribuídos em um delineamento em blocos casualizados, com cinco tratamentos, quatro blocos e dois suínos por unidade experimental. Os tratamentos consistiram de uma ração à base de milho e farelo de soja e outras quatro com a inclusão de 60 por cento de diferentes tipos de milheto (IAPAR, COMUM, BN2 e BN2S, sendo este com espigueta). Não foram observadas diferenças entre os tipos de milheto para consumo diário de ração, ganho diário de peso, conversão alimentar e características de carcaça. Os resultados sugerem que é viável a inclusão de 60 por cento de milheto da linhagem IAPAR, da cultivar "COMUM", das variedades BN2 ou BN2S (com a espigueta), nas rações de suínos em crescimento e terminação.


A performance trial was carried out to evaluate the nutritional and economic feasibility of growing-finishing pig diets with 60 percent of different pearl millets. Forty crossbreed pigs were used during growing (initial weight 30.3±2.9kg) and finishing (54.3±4.1kg) phases. Pigs were allotted in a randomized blocks design with 5 treatments, 4 blocs and 2 pigs per experimental unit. The treatments consisted in a corn-soybean meal and other 4 diets containing 60 percent of inclusion of different types of pearl millet (IAPAR, COMUM, BN2 and BN2S. The last is pearl millet BN2 in spikelets). There was not difference for types of pearl millet on daily feed intake, daily weight gain, feed: gain ratio and carcass traits. The results suggested that it is possible to use 60 percent of IAPAR, COMUM, BN2 and BN2S pearl millet in growing-finishing pig diets.

19.
Epilepsy Behav ; 6(3): 393-404, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15820349

RESUMO

Bilateral perisylvian polymicrogyria (BPP) is a malformation of cortical development, frequently associated with severe dysarthria or anarthria. BPP patients are therefore often labeled as severely retarded, but a detailed neuropsychological profile has not been reported to date. In a series of 14 patients, we demonstrated that only a minority had extremely low intelligence, and that some aspects of cognitive function correlated with the extent of the cortical disorganization. Early age at seizure onset correlated positively with Performance IQ scores (P<0.05) and negatively with the extent of the lesion (P<0.01), reflecting that patients with more severe BPP are more likely to have early seizure onset, resulting in greater interference with ongoing cognitive development. Receptive and expressive language skills were found to be equally poor. Frontal lobe function and memory abilities were relatively well preserved, suggesting that the observed cognitive profiles were related, at least in part, to specific areas of cortical dysfunction and not only to global dysfunction.


Assuntos
Córtex Cerebral/anormalidades , Córtex Cerebral/fisiopatologia , Cognição/fisiologia , Lateralidade Funcional/fisiologia , Adulto , Mapeamento Encefálico , Córtex Cerebral/cirurgia , Eletroencefalografia/métodos , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Inteligência/fisiologia , Imageamento por Ressonância Magnética/métodos , Masculino , Memória/fisiologia , Pessoa de Meia-Idade , Exame Neurológico/métodos , Testes Neuropsicológicos/estatística & dados numéricos , Resolução de Problemas/fisiologia , Convulsões/patologia , Convulsões/fisiopatologia , Comportamento Verbal/fisiologia
20.
Can J Neurol Sci ; 32(4): 477-82, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16408578

RESUMO

PURPOSE: Focal cortical dysplasia (FCD) is one of the most common underlying pathologic substrates in patients with medically intractable epilepsy. While magnetic resonance imaging (MRI) evidence of FCD is an important predictor of good surgical outcome, conventional MRI is not sensitive enough to detect all lesions. Previous reports of diffusion tensor imaging (DTI) abnormalities in FCD suggest the potential of DTI in the detection of FCD. The purpose of this study was to study subcortical white matter underlying small lesions of FCD using DTI. METHODS: Five patients with medically intractable epilepsy and FCD were investigated. Diffusion tensor imaging images were acquired (20 contiguous 3 mm thick axial slices) with maps of fractional anisotropy (FA), trace apparent diffusion coefficient (trace/3 ADC), and principal eigenvalues (ADC parallel and ADC perpendicular to white matter tracts) being calculated for each slice. Region of interest analysis was used to compare subcortical white matter ipsilateral and contralateral to the lesion. RESULTS: Three subjects with FCD associated with underlying white matter hyperintensities on T2 weighted MRI were observed to have increased trace/3 ADC, reduced fractional anisotropy and increased perpendicular water diffusivity which was greater than the relative increase in the parallel diffusivity. No DTI abnormalities were identified in two patients with FCD without white matter hyperintensities on conventional T2-weighted MRI. CONCLUSIONS: While DTI abnormalities in FCD with obvious white matter involvement are consistent with micro-structural degradation of the underlying subcortical white matter, DTI changes were not identified in FCD lesions with normal appearing white matter.


Assuntos
Encefalopatias/patologia , Encéfalo , Diagnóstico por Imagem , Adolescente , Adulto , Encéfalo/anatomia & histologia , Encéfalo/patologia , Encefalopatias/complicações , Epilepsia/etiologia , Feminino , Humanos , Masculino
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