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1.
Psychophysiology ; 61(5): e14525, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38234038

RESUMO

Ongoing brain activity preceding visual stimulation has been suggested to shape conscious perception. According to the pulsed inhibition framework, bouts of functional inhibition arise in each alpha cycle (every ~100 ms), allowing information to be processed in a pulsatile manner. Consequently, it has been hypothesized that perceptual outcome can be influenced by the specific phase of alpha oscillations prior to the stimulus onset, although empirical findings are controversial. In this study, we aimed to shed light on the role of prestimulus alpha oscillations in visual perception. To this end, we recorded electroencephalographic activity, while participants performed three near-threshold visual detection tasks with different attentional involvement: a no-cue task, a noninformative cue task (50% validity), and an informative cue task (100% validity). Cluster-based permutation statistics were complemented with Bayesian analyses to test the effect of prestimulus oscillatory amplitude and phase on visual awareness. We additionally examined whether these effects differed in trials with low and high oscillatory amplitude, as expected from the pulsed inhibition theory. Our results show a clear effect of prestimulus alpha amplitude on conscious perception, but only when alpha fluctuated spontaneously. In contrast, we did not find any evidence that prestimulus alpha phase influenced perceptual outcome, not even when differentiating between low- and high-amplitude trials. Furthermore, Bayesian analysis provided moderate evidence in favor of the absence of phase effects. Taken together, our results challenge the central theoretical predictions of the pulsed inhibition framework, at least for the particular experimental conditions used here.


Assuntos
Eletroencefalografia , Percepção Visual , Humanos , Teorema de Bayes , Percepção Visual/fisiologia , Atenção/fisiologia , Estimulação Luminosa/métodos , Ritmo alfa/fisiologia
2.
Neuroimage ; 258: 119373, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35700947

RESUMO

Brain oscillations are considered to play a pivotal role in neural communication. However, detailed information regarding the typical oscillatory patterns of individual brain regions is surprisingly scarce. In this study we applied a multivariate data-driven approach to create an atlas of the natural frequencies of the resting human brain on a voxel-by-voxel basis. We analysed resting-state magnetoencephalography (MEG) data from 128 healthy adult volunteers obtained from the Open MEG Archive (OMEGA). Spectral power was computed in source space in 500 ms steps for 82 frequency bins logarithmically spaced from 1.7 to 99.5 Hz. We then applied k-means clustering to detect characteristic spectral profiles and to eventually identify the natural frequency of each voxel. Our results provided empirical confirmation of the canonical frequency bands and revealed a region-specific organisation of intrinsic oscillatory activity, following both a medial-to-lateral and a posterior-to-anterior gradient of increasing frequency. In particular, medial fronto-temporal regions were characterised by slow rhythms (delta/theta). Posterior regions presented natural frequencies in the alpha band, although with differentiated generators in the precuneus and in sensory-specific cortices (i.e., visual and auditory). Somatomotor regions were distinguished by the mu rhythm, while the lateral prefrontal cortex was characterised by oscillations in the high beta range (>20 Hz). Importantly, the brain map of natural frequencies was highly replicable in two independent subsamples of individuals. To the best of our knowledge, this is the most comprehensive atlas of ongoing oscillatory activity performed to date. Critically, the identification of natural frequencies is a fundamental step towards a better understanding of the functional architecture of the human brain.


Assuntos
Magnetoencefalografia , Descanso , Adulto , Encéfalo , Mapeamento Encefálico/métodos , Humanos , Magnetoencefalografia/métodos , Lobo Temporal
3.
Chem Soc Rev ; 50(15): 8511-8595, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34128513

RESUMO

Microporous zeolite-type materials, with crystalline porous structures formed by well-defined channels and cages of molecular dimensions, have been widely employed as heterogeneous catalysts since the early 1960s, due to their wide variety of framework topologies, compositional flexibility and hydrothermal stability. The possible selection of the microporous structure and of the elements located in framework and extraframework positions enables the design of highly selective catalysts with well-defined active sites of acidic, basic or redox character, opening the path to their application in a wide range of catalytic processes. This versatility and high catalytic efficiency is the key factor enabling their use in the activation and conversion of different alkanes, ranging from methane to long chain n-paraffins. Alkanes are highly stable molecules, but their abundance and low cost have been two main driving forces for the development of processes directed to their upgrading over the last 50 years. However, the availability of advanced characterization tools combined with molecular modelling has enabled a more fundamental approach to the activation and conversion of alkanes, with most of the recent research being focused on the functionalization of methane and light alkanes, where their selective transformation at reasonable conversions remains, even nowadays, an important challenge. In this review, we will cover the use of microporous zeolite-type materials as components of mono- and bifunctional catalysts in the catalytic activation and conversion of C1+ alkanes under non-oxidative or oxidative conditions. In each case, the alkane activation will be approached from a fundamental perspective, with the aim of understanding, at the molecular level, the role of the active sites involved in the activation and transformation of the different molecules and the contribution of shape-selective or confinement effects imposed by the microporous structure.

4.
J Environ Manage ; 295: 113362, 2021 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-34346390

RESUMO

This review compiles recent advances and challenges on photocatalytic treatment of wastewater using nanoparticles, nanocomposites, and polymer nanocomposites as photocatalyst. The review provides an overview of the fundamental principles of photocatalytic treatment along the recent advances on photocatalytic treatment, especially on the modification strategies and operational conditions to enhance treatment efficiency and removal of recalcitrant organic contaminants. The different types of photocatalysts along the key factors influencing their performance are also critically discussed and recommendations for future research are provided.

5.
Neurobiol Learn Mem ; 169: 107177, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32035983

RESUMO

Mesial temporal lobe epilepsy (mTLE) is a neurological disorder associated with histopathological changes in different subfields of the hippocampus. These alterations have been associated with memory difficulties. In this study, we tested the hypothesis that these difficulties stem on mnemonic discrimination impairment due to a reduced ability to make similar representations more distinct, leading to an increased susceptibility to interference. With this aim, we used a visual mnemonic discrimination task and evaluated the ability of a group of patients with unilateral mTLE, relative to controls, to discriminate between a studied item and a new foil item, as a function of the similarity between them, and of the number of exemplars from a category stored in memory. We found that patients performed worse than controls when the studied item had to be discriminated from a physically similar new object from the same basic-level category. Crucially, reliable differences between groups were observable in the conditions in which more exemplars from a category were held in memory. In the conditions in which the studied item had to be discriminated from a foil from a different basic-level category, there were no differences between groups, with one exception. Neither a general cognitive impairment nor a general memory impairment could account for this pattern of results. Current findings indicate that patients found more difficulties in conditions with higher interference, which poses greater demands for pattern separation. A disruption of pattern separation processes resulting from hippocampal damage provides a reasonable interpretation for these results. Future studies should explore the causal relationship between hippocampal subfields integrity and mnemonic discrimination capacity in mTLE patients.


Assuntos
Discriminação Psicológica , Epilepsia do Lobo Temporal/psicologia , Memória , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Reconhecimento Psicológico , Adulto Jovem
6.
Water Environ Res ; 90(2): 172-179, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29348002

RESUMO

The biomass concentrator reactor (BCR), a gravity flow membrane bioreactor (MBR) design, was evaluated for use in treating a municipal wastewater stream. The BCR operates with less than 2.5 cm of pressure head and uses a 3 to 4 mm thick tortuous path membrane with pore size ranging from 18 to 28 µm to achieve solids separation. A two-stage, aerobic/anoxic reactor was evaluated for the removal of chemical oxygen demand (COD), ammonia, total nitrogen, and solids separation. The reactor was fed 72 L/day, with a hydraulic retention time of 9.3 hours, and had a solids retention time of 20 days. The influent COD was reduced by 93%, whereas, influent ammonia was reduced below 0.1 mg/L and total nitrogen was reduced by 53.7%. A lack of readily biodegradable COD limited denitrification and thus total nitrogen removal. The reactor solids were retained completely in the reactor by the membrane for the duration of testing.


Assuntos
Reatores Biológicos , Membranas Artificiais , Eliminação de Resíduos Líquidos/métodos , Nitrogênio , Oxigênio , Águas Residuárias , Purificação da Água
7.
Appl Environ Microbiol ; 83(10)2017 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-28283527

RESUMO

To better understand the impacts of Corexit 9500 on the structure and activity levels of hydrocarbon-degrading microbial communities, we analyzed next-generation 16S rRNA gene sequencing libraries of hydrocarbon enrichments grown at 5 and 25°C using both DNA and RNA extracts as the sequencing templates. Oil biodegradation patterns in both 5 and 25°C enrichments were consistent with those reported in the literature (i.e., aliphatics were degraded faster than aromatics). Slight increases in biodegradation were observed in the presence of Corexit at both temperatures. Differences in community structure were observed between treatment conditions in the DNA-based libraries. The 25°C consortia were dominated by Vibrio, Idiomarina, Marinobacter, Alcanivorax, and Thalassospira species, while the 5°C consortia were dominated by several species of the genera Flavobacterium, Alcanivorax, and Oleispira Most of these genera have been linked to hydrocarbon degradation and have been observed after oil spills. Colwellia and Cycloclasticus, known aromatic degraders, were also found in these enrichments. The addition of Corexit did not have an effect on the active bacterial community structure of the 5°C consortia, while at 25°C, a decrease in the relative abundance of Marinobacter was observed. At 25°C, Thalassospira, Marinobacter, and Idiomarina were present at higher relative abundances in the RNA than DNA libraries, suggesting that they were active in degradation. Similarly, Oleispira was greatly stimulated by the addition of oil at 5°C.IMPORTANCE While dispersants such as Corexit 9500 can be used to treat oil spills, there is still debate on the effectiveness on enhancing oil biodegradation and its potential toxic effect on oil-degrading microbial communities. The results of this study provide some insights on the microbial dynamics of hydrocarbon-degrading bacterial populations in the presence of Corexit 9500. Operational taxonomic unit (OTU) analyses indicated that several OTUs were inhibited by the addition of Corexit. Conversely, a number of OTUs were stimulated by the addition of the dispersant, many of which were identified as known hydrocarbon-degrading bacteria. The results highlight the value of using RNA-based methods to further understand the impact of dispersant on the overall activity of different hydrocarbon-degrading bacterial groups.


Assuntos
Bactérias/efeitos dos fármacos , Bactérias/metabolismo , Lipídeos/farmacologia , Bactérias/classificação , Bactérias/genética , Biodegradação Ambiental , Hidrocarbonetos/metabolismo , Petróleo/metabolismo , Poluição por Petróleo/análise , Filogenia
8.
J Neurosci ; 35(23): 8768-76, 2015 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-26063911

RESUMO

Accumulating evidence suggests that visual object understanding involves a rapid feedforward sweep, after which subsequent recurrent interactions are necessary. The extent to which recurrence plays a critical role in object processing remains to be determined. Recent studies have demonstrated that recurrent processing is modulated by increasing semantic demands. Differentially from previous studies, we used dynamic causal modeling to model neural activity recorded with magnetoencephalography while 14 healthy humans named two sets of visual objects that differed in the degree of semantic accessing demands, operationalized in terms of the values of basic psycholinguistic variables associated with the presented objects (age of acquisition, frequency, and familiarity). This approach allowed us to estimate the directionality of the causal interactions among brain regions and their associated connectivity strengths. Furthermore, to understand the dynamic nature of connectivity (i.e., the chronnectome; Calhoun et al., 2014) we explored the time-dependent changes of effective connectivity during a period (200-400 ms) where adding semantic-feature information improves modeling and classifying visual objects, at 50 ms increments. First, we observed a graded involvement of backward connections, that became active beyond 200 ms. Second, we found that semantic demands caused a suppressive effect in the backward connection from inferior frontal cortex (IFC) to occipitotemporal cortex over time. These results complement those from previous studies underscoring the role of IFC as a common source of top-down modulation, which drives recurrent interactions with more posterior regions during visual object recognition. Crucially, our study revealed the inhibitory modulation of this interaction in situations that place greater demands on the conceptual system.


Assuntos
Mapeamento Encefálico , Córtex Cerebral/fisiopatologia , Demência Frontotemporal/fisiopatologia , Nomes , Reconhecimento Visual de Modelos/fisiologia , Adulto , Análise de Variância , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Estimulação Luminosa , Tempo de Reação/fisiologia
9.
Epilepsia ; 57(5): 841-51, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27020612

RESUMO

OBJECTIVE: Small temporal pole encephalocele (STPE) can be the pathologic substrate of epilepsy in a subgroup of patients with noninformative magnetic resonance imaging (MRI). Herein, we analyzed the clinical, neurophysiologic, and radiologic features of the epilepsy found in 22 patients with STPE, and the frequency of STPE in patients with refractory focal epilepsy (RFE). METHODS: We performed an observational study of all patients with STPE identified at our epilepsy unit from January 2007 to December 2014. Cases were detected through a systematic search of our database of RFE patients evaluated for surgery, and a prospective collection of patients identified at the outpatient clinic. The RFE database was also employed to analyze the frequency of STPE among the different clinical subgroups. RESULTS: We identified 22 patients with STPE (11 women), including 12 (4.0%) of 303 patients from the RFE database, and 10 from the outpatient clinic. The median age was 51.5 years (range 29-75) and the median age at seizure onset was 38.5 years (range 15-73). Typically, 12 (80%) of 15 patients with left STPE reported seizures with impairment of language. Among the RFE cases, STPE were found in 9.6% of patients with temporal lobe epilepsy (TLE), and in 0.5% of those with extra-TLE (p = 0.0001). STPEs were more frequent in TLE patients with an initial MRI study reported as normal (23.3%) than in those with MRI-visible lesions (1.4%; p = 0.0002). Stereo-electroencephalography was performed in four patients, confirming the localization of the epileptogenic zone at the temporal pole with late participation of the hippocampus. Long-term seizure control was achieved in four of five operated patients. SIGNIFICANCE: STPE can be a hidden cause of TLE in a subgroup of patients with an initial report of "normal" MRI. Early identification of this lesion may help to select patients for presurgical evaluation and tailored resection.


Assuntos
Encéfalo/diagnóstico por imagem , Encefalocele/complicações , Epilepsia do Lobo Temporal/diagnóstico por imagem , Epilepsia do Lobo Temporal/etiologia , Imageamento por Ressonância Magnética , Meningocele/complicações , Adulto , Idoso , Bases de Dados Factuais/estatística & dados numéricos , Eletroencefalografia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estudos Retrospectivos , Gravação em Vídeo
11.
J Neurosci ; 33(19): 8227-36, 2013 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-23658161

RESUMO

Acetylcholine (ACh) is a neuromodulatory transmitter implicated in perception and learning under uncertainty. This study combined computational simulations and pharmaco-electroencephalography in humans, to test a formulation of perceptual inference based upon the free energy principle. This formulation suggests that ACh enhances the precision of bottom-up synaptic transmission in cortical hierarchies by optimizing the gain of supragranular pyramidal cells. Simulations of a mismatch negativity paradigm predicted a rapid trial-by-trial suppression of evoked sensory prediction error (PE) responses that is attenuated by cholinergic neuromodulation. We confirmed this prediction empirically with a placebo-controlled study of cholinesterase inhibition. Furthermore, using dynamic causal modeling, we found that drug-induced differences in PE responses could be explained by gain modulation in supragranular pyramidal cells in primary sensory cortex. This suggests that ACh adaptively enhances sensory precision by boosting bottom-up signaling when stimuli are predictable, enabling the brain to respond optimally under different levels of environmental uncertainty.


Assuntos
Acetilcolina/metabolismo , Encéfalo/fisiologia , Aprendizagem/fisiologia , Modelos Neurológicos , Percepção/fisiologia , Estimulação Acústica , Adolescente , Adulto , Algoritmos , Encéfalo/efeitos dos fármacos , Mapeamento Encefálico , Inibidores da Colinesterase/farmacologia , Simulação por Computador , Método Duplo-Cego , Eletroencefalografia , Potenciais Evocados Auditivos/efeitos dos fármacos , Potenciais Evocados Auditivos/fisiologia , Feminino , Galantamina/farmacologia , Humanos , Aprendizagem/efeitos dos fármacos , Masculino , Testes Neuropsicológicos , Percepção/efeitos dos fármacos , Valor Preditivo dos Testes , Adulto Jovem
12.
J Neurosci ; 33(31): 12679-88, 2013 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-23904604

RESUMO

An increasing amount of evidence supports a crucial role for the anterior temporal lobe (ATL) in semantic processing. Critically, a selective disruption of the functional connectivity between left and right ATLs in patients with chronic aphasic stroke has been illustrated. The aim of the current study was to evaluate the consequences that lesions on the ATL have on the neurocognitive network supporting semantic cognition. Unlike previous work, in this magnetoencephalography study we selected a group of patients with small lesions centered on the left anteroventral temporal lobe before surgery. We then used an effective connectivity method (i.e., dynamic causal modeling) to investigate the consequences that these lesions have on the functional interactions within the network. This approach allowed us to evaluate the directionality of the causal interactions among brain regions and their associated connectivity strengths. Behaviorally, we found that semantic processing was altered when patients were compared with a strictly matched group of controls. Dynamic causal modeling for event related responses revealed that picture naming was associated with a bilateral frontotemporal network, encompassing feedforward and feedback connections. Comparison of specific network parameters between groups revealed that patients displayed selective network adjustments. Specifically, backward connectivity from anterior to posterior temporal lobe was decreased in the ipsilesional hemisphere, whereas it was enhanced in the contralesional hemisphere. These results reinforce the relevance of ATL in semantic memory, as well as its amodal organization, and highlight the role of feedback connections in enabling the integration of the semantic information.


Assuntos
Epilepsia do Lobo Temporal/complicações , Epilepsia do Lobo Temporal/patologia , Transtornos da Memória/etiologia , Nomes , Vias Neurais/patologia , Lobo Temporal/patologia , Adulto , Aprendizagem por Associação , Mapeamento Encefálico , Eletroencefalografia , Feminino , Humanos , Imageamento por Ressonância Magnética , Magnetoencefalografia , Masculino , Transtornos da Memória/diagnóstico , Pessoa de Meia-Idade , Modelos Biológicos , Vias Neurais/diagnóstico por imagem , Testes Neuropsicológicos , Estimulação Luminosa , Tomografia por Emissão de Pósitrons , Estudos Retrospectivos , Lobo Temporal/diagnóstico por imagem , Gravação em Vídeo
13.
Eur J Neurosci ; 40(2): 2399-405, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24750388

RESUMO

Selective attention mechanisms allow us to focus on information that is relevant to the current behavior and, equally important, ignore irrelevant information. An influential model proposes that oscillatory neural activity in the alpha band serves as an active functional inhibitory mechanism. Recent studies have shown that, in the same way that attention can be selectively oriented to bias sensory processing in favor of relevant stimuli in perceptual tasks, it is also possible to retrospectively orient attention to internal representations held in working memory. However, these studies have not explored the associated oscillatory phenomena. In the current study, we analysed the patterns of neural oscillatory activity recorded with magnetoencephalography while participants performed a change detection task, in which a spatial retro-cue was presented during the maintenance period, indicating which item or items were relevant for subsequent retrieval. Participants benefited from retro-cues in terms of accuracy and reaction time. Retro-cues also modulated oscillatory activity in the alpha and gamma frequency bands. We observed greater alpha activity in a ventral visual region ipsilateral to the attended hemifield, thus supporting its suppressive role, i.e., a functional disengagement of task-irrelevant regions. Accompanying this modulation, we found an increase in gamma activity contralateral to the attended hemifield, which could reflect attentional orienting and selective processing. These findings suggest that the oscillatory mechanisms underlying attentional orienting to representations held in working memory are similar to those engaged when attention is oriented in the perceptual space.


Assuntos
Ritmo alfa , Atenção , Ritmo Gama , Memória de Curto Prazo , Adulto , Feminino , Humanos , Masculino , Córtex Visual/fisiologia
14.
Brain Cogn ; 84(1): 90-6, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24333830

RESUMO

Multi-store models of working memory (WM) have given way to more dynamic approaches that conceive WM as an activated subset of long-term memory (LTM). The resulting framework considers that memory representations are governed by a hierarchy of accessibility. The activated part of LTM holds representations in a heightened state of activation, some of which can reach a state of immediate accessibility according to task demands. Recent neuroimaging studies have studied the neural basis of retrieval information with different states of accessibility. It was found that the medial temporal lobe (MTL) was involved in retrieving information within immediate access store and outside this privileged zone. In the current study we further explored the contribution of MTL to WM retrieval by analyzing the consequences of MTL damage to this process considering the state of accessibility of memory representations. The performance of a group of epilepsy patients with left hippocampal sclerosis in a 12-item recognition task was compared with that of a healthy control group. We adopted an embedded model of WM that distinguishes three components: the activated LTM, the region of direct access, and a single-item focus of attention. Groups did not differ when retrieving information from single-item focus, but patients were less accurate retrieving information outside focal attention, either items from LTM or items expected to be in the WM range. Analyses focused on items held in the direct access buffer showed that consequences of MTL damage were modulated by the level of accessibility of memory representations, producing a reduced capacity.


Assuntos
Epilepsia do Lobo Temporal/psicologia , Memória de Curto Prazo , Rememoração Mental , Adulto , Feminino , Humanos , Masculino , Reconhecimento Psicológico
15.
Sci Total Environ ; 934: 173237, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38761940

RESUMO

Per- and poly-fluoroalkyl substances (PFAS) have emerged as newly regulated micropollutants, characterised by extreme recalcitrance and environmental toxicity. Constructed wetlands (CWs), as a nature-based solution, have gained widespread application in sustainable water and wastewater treatment and offer multiple environmental and societal benefits. Despite CWs potential, knowledge gaps persist in their PFAS removal capacities, associated mechanisms, and modelling of PFAS fate. This study carried out a systematic literature review, supplemented by unpublished experimental data, demonstrating the promise of CWs for PFAS removal from the influents of varying sources and characteristics. Median removal performances of 64, 46, and 0 % were observed in five free water surface (FWS), four horizontal subsurface flow (HF), and 18 vertical flow (VF) wetlands, respectively. PFAS adsorption by the substrate or plant root/rhizosphere was deemed as a key removal mechanism. Nevertheless, the available dataset resulted unsuitable for a quantitative analysis. Data-driven models, including multiple regression models and machine learning-based Artificial Neural Networks (ANN), were employed to predict PFAS removal. These models showed better predictive performance compared to various mechanistic models, which include two adsorption isotherms. The results affirmed that artificial intelligence is an efficient tool for modelling the removal of emerging contaminants with limited knowledge of chemical properties. In summary, this study consolidated evidence supporting the use of CWs for mitigating new legacy PFAS contaminants. Further research, especially long-term monitoring of full-scale CWs treating real wastewater, is crucial to obtain additional data for model development and validation.

16.
Neuroimage ; 72: 48-54, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23370058

RESUMO

Mesial temporal lobe epilepsy (mTLE) is the most prevalent form of focal epilepsy, and hippocampal sclerosis (HS) is considered the most frequent associated pathological finding. Recent connectivity studies have shown that abnormalities, either structural or functional, are not confined to the affected hippocampus, but can be found in other connected structures within the same hemisphere, or even in the contralesional hemisphere. Despite the role of hippocampus in memory functions, most of these studies have explored network properties at resting state, and in some cases compared connectivity values with neuropsychological memory scores. Here, we measured magnetoencephalographic responses during verbal working memory (WM) encoding in left mTLE patients and controls, and compared their effective connectivity within a frontotemporal network using dynamic causal modelling. Bayesian model comparison indicated that the best model included bilateral, forward and backward connections, linking inferior temporal cortex (ITC), inferior frontal cortex (IFC), and the medial temporal lobe (MTL). Test for differences in effective connectivity revealed that patients exhibited decreased ipsilesional MTL-ITC backward connectivity, and increased bidirectional IFC-MTL connectivity in the contralesional hemisphere. Critically, a negative correlation was observed between these changes in patients, with decreases in ipsilesional coupling among temporal sources associated with increases contralesional frontotemporal interactions. Furthermore, contralesional frontotemporal interactions were inversely related to task performance and level of education. The results demonstrate that unilateral sclerosis induced local and remote changes in the dynamic organization of a distributed network supporting verbal WM. Crucially, pre-(peri) morbid factors (educational level) were reflected in both cognitive performance and (putative) compensatory changes in physiological coupling.


Assuntos
Epilepsia do Lobo Temporal/fisiopatologia , Lateralidade Funcional/fisiologia , Memória de Curto Prazo/fisiologia , Vias Neurais/fisiopatologia , Adulto , Teorema de Bayes , Epilepsia do Lobo Temporal/patologia , Feminino , Hipocampo/patologia , Hipocampo/fisiopatologia , Humanos , Magnetoencefalografia , Masculino , Vias Neurais/patologia , Esclerose/patologia , Esclerose/fisiopatologia
17.
Environ Sci Technol ; 47(4): 1960-7, 2013 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-23363064

RESUMO

The reported persistence of the dioctyl sodium sulfosuccinate (DOSS) surfactant in Corexit 9500 in the oil plumes formed during the Deepwater Horizon oil spill has contributed to concerns regarding the biodegradability and bioavailability of dispersed oil and dispersants used as an oil spill countermeasure in the Gulf of Mexico. We studied the biodegradation of DOSS and dispersed South Louisiana crude oil (SLC) in laboratory microcosms. Two oil-degrading cultures from the Gulf of Mexico were isolated, one from the surface (meso) and one from close to the area of the Macondo well (cryo). Each was enriched on SLC, the former at 25 °C, the latter at 5 °C. Results indicated that the meso culture rapidly and completely degraded DOSS, alkanes, and aromatics. The cryo culture metabolized the same compounds but with a lag of 28 d and a remaining residual of iso-alkanes, n-C(30-35), and the 4-ring PAHs.


Assuntos
Alcanos/metabolismo , Ácido Dioctil Sulfossuccínico/metabolismo , Lipídeos , Petróleo/microbiologia , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Biodegradação Ambiental , Temperatura
18.
Epilepsy Behav ; 29(1): 172-7, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23973642

RESUMO

Studies of patients with temporal lobe epilepsy provide few descriptions of seizures that arise in the temporopolar and the anterior temporobasal brain region. Based on connectivity, it might be assumed that the semiology of these seizures is similar to that of medial temporal lobe epilepsy. However, accumulating evidence suggests that the anterior temporobasal cortex may play an important role in the language system, which could account for particular features of seizures arising here. We studied the electroclinical features of seizures in patients with circumscribed temporopolar and temporobasal lesions in order to identify specific features that might differentiate them from seizures that originate in other temporal areas. Among 172 patients with temporal lobe seizures registered in our epilepsy unit in the last 15 years, 15 (8.7%) patients had seizures caused by temporopolar or anterior temporobasal lesions (11 left-sided lesions). The main finding in our study is that patients with left-sided lesions had aphasia during their seizures as the most prominent feature. In addition, while all patients showed normal to high intellectual functioning in standard neuropsychological testing, semantic impairment was found in a subset of 9 patients with left-sided lesions. This case series demonstrates that aphasic seizures without impairment of consciousness can result from small, circumscribed left anterior temporobasal and temporopolar lesions. Thus, the presence of speech manifestation during seizures should prompt detailed assessment of the structural integrity of the basal surface of the temporal lobe in addition to the evaluation of primary language areas.


Assuntos
Afasia/etiologia , Eletroencefalografia , Epilepsia do Lobo Temporal/complicações , Epilepsia do Lobo Temporal/patologia , Convulsões/etiologia , Gravação em Vídeo , Adolescente , Adulto , Afasia/diagnóstico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estudos Retrospectivos , Convulsões/diagnóstico
19.
Cereb Cortex ; 22(6): 1225-36, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21810779

RESUMO

Accumulating evidence suggests a role for the medial temporal lobe (MTL) in working memory (WM). However, little is known concerning its functional interactions with other cortical regions in the distributed neural network subserving WM. To reveal these, we availed of subjects with MTL damage and characterized changes in effective connectivity while subjects engaged in WM task. Specifically, we compared dynamic causal models, extracted from magnetoencephalographic recordings during verbal WM encoding, in temporal lobe epilepsy patients (with left hippocampal sclerosis) and controls. Bayesian model comparison indicated that the best model (across subjects) evidenced bilateral, forward, and backward connections, coupling inferior temporal cortex (ITC), inferior frontal cortex (IFC), and MTL. MTL damage weakened backward connections from left MTL to left ITC, a decrease accompanied by strengthening of (bidirectional) connections between IFC and MTL in the contralesional hemisphere. These findings provide novel evidence concerning functional interactions between nodes of this fundamental cognitive network and sheds light on how these interactions are modified as a result of focal damage to MTL. The findings highlight that a reduced (top-down) influence of the MTL on ipsilateral language regions is accompanied by enhanced reciprocal coupling in the undamaged hemisphere providing a first demonstration of "connectional diaschisis."


Assuntos
Epilepsia do Lobo Temporal/patologia , Epilepsia do Lobo Temporal/fisiopatologia , Hipocampo/patologia , Hipocampo/fisiologia , Memória de Curto Prazo/fisiologia , Adulto , Feminino , Humanos , Magnetoencefalografia/métodos , Masculino , Vias Neurais/patologia , Vias Neurais/fisiologia , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Esclerose/patologia , Adulto Jovem
20.
Sci Total Environ ; 900: 165739, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-37499826

RESUMO

There is increasing demand for low-carbon remediation strategies for reducing greenhouse gas emissions and promoting sustainable development in the management of environmental contamination. This trend is within the broader context of sustainable remediation strategies that balance environmental, economic, and social aspects. This article critically reviewed existing literature to evaluate and compare various low-carbon remediation methods, such as bioremediation, phytoremediation, in situ chemical oxidation, soil vapour extraction, and electrokinetic remediation, to identify suitable techniques for the remediation of oil-contaminated sites in the Niger Delta region of Nigeria. We analysed the UK sustainable remediation frameworks (SuRF-UK) to glean lessons for the Nigerian context. Our findings indicate that bioremediation and phytoremediation are particularly promising low-carbon remediation technologies for the Niger Delta region due to their cost-effectiveness and adaptability to local conditions. We proposed a framework that deeply considers opportunities for achieving multiple goals including effective remediation and limited greenhouse gas emissions while returning net social and economic benefit to local communities. The proposed framework will help decision makers to implement effective remediation technologies that meet sustainability indices, integrates emissions considerations return net environmental benefit to local communities. There is a need for policymakers to establish and enforce policies and regulations that support sustainable remediation practises, build the capacity of stakeholders, invest in research and development, and promote collaboration among stakeholders to create a regulatory environment that supports sustainable remediation practises and promotes environmental sustainability in the region. This study provides insights for achieving low-carbon remediation in regions addressing land contamination by different contaminants and facilitates the adoption of remediation technologies that consider contextual socio-economic and environmental indices for sustainable development.

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