Search results for "roe"
showing 10 items of 9822 documents
Malondialdehyde in early phase of acute pancreatitis
2011
Aims: to assess oxidative stress in acute pancreatitis, its evolution over time and its relationship with the severity of the disease. Methods: during a two-year period, patients with acute pancreatitis with less than 24 hours of pain were evaluated. Serum was obtained the first, second and fourth day from admittance, if complications were detected, and after recovery. Malondialdehyde was determined by high performance liquid chromatography. Twenty healthy volunteers constituted the control group. Malondialdehyde between groups was compared with Mann-Whitney and Kruskal-Wallis tests; malondialdehyde evolution was studied with Wilcoxon test. Results: one hundred and sixty-nine patients were …
LOW-RANK APPROXIMATION BASED NON-NEGATIVE MULTI-WAY ARRAY DECOMPOSITION ON EVENT-RELATED POTENTIALS
2014
Non-negative tensor factorization (NTF) has been successfully applied to analyze event-related potentials (ERPs), and shown superiority in terms of capturing multi-domain features. However, the time-frequency representation of ERPs by higher-order tensors are usually large-scale, which prevents the popularity of most tensor factorization algorithms. To overcome this issue, we introduce a non-negative canonical polyadic decomposition (NCPD) based on low-rank approximation (LRA) and hierarchical alternating least square (HALS) techniques. We applied NCPD (LRAHALS and benchmark HALS) and CPD to extract multi-domain features of a visual ERP. The features and components extracted by LRAHALS NCP…
Multi-domain feature extraction for small event-related potentials through nonnegative multi-way array decomposition from low dense array EEG
2013
Non-negative Canonical Polyadic decomposition (NCPD) and non-negative Tucker decomposition (NTD) were compared for extracting the multi-domain feature of visual mismatch negativity (vMMN), a small event-related potential (ERP), for the cognitive research. Since signal-to-noise ratio in vMMN is low, NTD outperformed NCPD. Moreover, we proposed an approach to select the multi-domain feature of an ERP among all extracted features and discussed determination of numbers of extracted components in NCPD and NTD regarding the ERP context.
Exploring the switching of the focus of attention within working memory: A combined event-related potential and behavioral study.
2018
Abstract Working memory enables humans to maintain selected information for cognitive processes and ensures instant access to the memorized contents. Theories suggest that switching the focus of attention between items within working memory realizes the access. This is reflected in object-switching costs in response times when the item for the task processing is to be changed. Another correlate of attentional allocation in working memory is the P3a-component of the human event-related potential. The aim of this study was to demonstrate that switching of attention within working memory is a separable processing step. Participants completed a cued memory-updating task in which they were instr…
k-Nearest neighbour local linear prediction of scalp EEG activity during intermittent photic stimulation
2011
The characterization of the EEG response to photic stimulation (PS) is an important issue with significant clinical relevance. This study aims to quantify and map the complexity of the EEG during PS, where complexity is measured as the degree of unpredictability resulting from local linear prediction. EEG activity was recorded with eyes closed (EC) and eyes open (EO) during resting and PS at 5, 10, and 15. Hz in a group of 30 healthy subjects and in a case-report of a patient suffering from cerebral ischemia. The mean squared prediction error (MSPE) resulting from k-nearest neighbour local linear prediction was calculated in each condition as an index of EEG unpredictability. The linear or …
Reliability of Magnetoencephalography and High-Density Electroencephalography Resting-State Functional Connectivity Metrics
2019
Resting-state connectivity, for example, based on magnetoencephalography (MEG) or electroencephalography (EEG), is a widely used method for characterizing brain networks and a promising imaging biomarker. However, there is no established standard as to which method, modality, and analysis variant is preferable and there is only limited knowledge on the reproducibility, an important prerequisite for clinical application. We conducted an MEG-/ high-density (hd)-EEG-study on 22 young healthy adults, who were measured twice in a scan/rescan design after 7 – 2 days. Reliability of resting-state (15 min, eyes-closed) connectivity in source space was calculated via intraclass correlation coefficie…
Role of sensorimotor areas in early detection of motor errors: An EEG and TMS study
2019
Abstract Action execution is prone to errors and, while engaged in interaction, our brain is tuned to detect deviations from what one expects from other’s action. Prior research has shown that Event-Related-Potentials (ERPs) are specifically modulated by the observation of action mistakes interfering with goal achievement. However, in complex and modular actions, embedded motor errors do not necessarily produce an immediate effect on the global goal. Here we dissociate embedded motor goals from global action goals by asking subjects to observe familiar but untrained knotting actions. During knotting an embedded motor error (i.e. the rope is inserted top-down instead of bottom-up during the …
Evaluation of texture analysis for the differential diagnosis of focal nodular hyperplasia from hepatocellular adenoma on contrast-enhanced CT images
2018
PurposeTo explore the value of CT texture analysis (CTTA) for differentiation of focal nodular hyperplasia (FNH) from hepatocellular adenoma (HCA) on contrast-enhanced CT (CECT).MethodsThis is a retrospective, IRB-approved study conducted in a single institution. A search of the medical records between 2008 and 2017 revealed 48 patients with 70 HCA and 50 patients with 62 FNH. All lesions were histologically proven and with available pre-operative CECT imaging. Hepatic arterial phase (HAP) and portal venous phase (PVP) were used for CTTA. Textural features were extracted using a commercially available research software (TexRAD). The differences between textural parameters of FNH and HCA wer…
Auditory event-related potentials (ERP) reflect temporal changes in speech stimuli
1997
We studied the brain's reactions to deviations in the duration of a stop consonant using event-related potentials in an oddball paradigm. A naturally produced nonsense word was used as a frequent standard stimulus which differed from two infrequently presented deviant stimuli only by the duration of the silence period inside the stop, making the consonant sound longer. Evoked responses to the deviant stimuli showed sharply rising negativity after the unexpected prolongation of the silence and a later negativity, the duration of which was related to the timing of the beginning of the second part of the deviant sound. This later negativity is, at least partly, elicited by a mismatch process t…
Neddylation inhibition ameliorates steatosis in NAFLD by boosting hepatic fatty acid oxidation via the DEPTOR-mTOR axis
2021
Objective Neddylation is a druggable and reversible ubiquitin-like post-translational modification upregulated in many diseases, including liver fibrosis, hepatocellular carcinoma, and more recently, non-alcoholic fatty liver disease (NAFLD). Herein, we propose to address the effects of neddylation inhibition and the underlying mechanisms in pre-clinical models of NAFLD. Methods Hepatic neddylation measured by immunohistochemical analysis and NEDD8 serum levels measured by ELISA assay were evaluated in NAFLD clinical and pre-clinical samples. The effects of neddylation inhibition by using a pharmacological small inhibitor, MLN4924, or molecular approaches were assessed in isolated mouse hep…