Toward a definition of MEG spike: Parametric description of spikes recorded simultaneously by MEG and depth electrodes

AbstractThere is not yet a formal definition of magnetoencephalography (MEG) spike. This study provides a parametric description and definition of clear-cut MEG spikes recorded simultaneously by MEG and depth electrodes (iEEG). A total number of 367 simultaneous MEG/iEEG spikes were selected for analysis. Distribution of morphologic spike parameters and detailed quantitative analysis of the basic morphologic characteristics of MEG spikes is provided

Efficient extraction of vicine from faba beans using reactive system of high-pressure CO2/water

ABSTRACT: Vicine from faba bean is a causative agent of favism, a genetic disease, which manifests as hemolytic anemia. Despite that low vicine varieties of faba bean exist, they are not widely cultivated. Several extraction methods of vicine from faba beans have been presented in the literature, however, their low efficiency associated to time-consuming and costly process limit the practical use. This work for the first time addresses the employment of high-pressure CO2-assisted extraction of the pyrimidine glycosides from the faba bean. For this purpose, the effect of temperature, CO2 pressure and time on vicine extraction was scrutinized using Box-Behnken design of experiments. Response surface methodology was used to determine the optimal extraction conditions. At 40.7 °C, 8.1 bar of CO2 pressure and 5.1 min of extraction, 81% of total vicine should be extracted from faba bean.info:eu-repo/semantics/publishedVersio

Development of a sustainable, simple, and robust method for efficient l-DOPA extraction

ABSTRACT: l-3,4-dihydroxyphenylalanine (l-DOPA) is a medically relevant compound in Parkinson's disease therapy. Several extraction methods of l-DOPA from beans, including velvet and faba beans, have been described in the literature. However, these methods require the use of strong acids, long extraction times, or complex downstream processing, which makes the extraction of l-DOPA expensive and energy-demanding, limiting its industrial application. In addition, the stability of l-DOPA during the extraction process is critical, further complicating the extraction of adequate amounts of this amino acid. This work is the first report on a simple, rapid, greener, and robust extraction method of l-DOPA. The developed method consists of a quick homogenization step followed by a double extraction with 0.2% v/v acetic acid for 20 min and was applied to faba bean at a ratio of 1:25 with respect to the extracting solvent. This study also investigated the stability of l-DOPA during extraction and thermal treatment. The proposed method demonstrated to be robust and extraordinarily efficient for numerous cultivars of faba bean, velvet bean, and food products containing faba beans.info:eu-repo/semantics/publishedVersio

Influence of nitrogen on the tribological properties of a-C:H layers on the polycarbonate substrates

Polycarbonate (PC) possesses many commercial applications. However, PC is still limited to non-abrasive and chemical-free environments due to its low hardness, low scratching resistance and high susceptibility to chemical attacks. To overcome this limitation, PC can be coated by hydrogenated amorphous carbon layers. The a-C:H layers have very attractive properties such as high hardness, infrared transparency, chemical inertness, low friction coefficients, and biocompatibility. Addition of nitrogen in the structure allows lowering internal stress and improve tribological properties of a-C:H layers. In this work, a-C:N:H layers were deposited from mixture CH4/N2 gases by RF PECVD method. Effects of the nitrogen incorporation on structure and tribological properties of deposited layers were investigated. The structure of layers were characterized by Fourier Transform Infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The friction coefficient, wear resistance of a-C:H:N layers were estimated by tribometer in ball-on-disc configuration. The IR spectra of the obtained layers have demonstrated a presence of nitrogen bonded both to carbon and to hydrogen. A formation of the following bonds has been confirmed: -C≡N, -NH2, -C−NH2, >C=NH. They are all typical for a-C:N:H layers. The tribological tests have shown that the layers reduce the friction coefficient of the polycarbonate (up to 50 %) and considerably improve wear resistance

Influence of metallic artifact filtering on MEG signals for source localization during interictal epileptiform activity

Objective. Medical intractable epilepsy is a common condition that affects 40% of epileptic patients that generally have to undergo resective surgery. Magnetoencephalography (MEG) has been increasingly used to identify the epileptogenic foci through equivalent current dipole (ECD) modeling, one of the most accepted methods to obtain an accurate localization of interictal epileptiform discharges (IEDs). Modeling requires that MEG signals are adequately preprocessed to reduce interferences, a task that has been greatly improved by the use of blind source separation (BSS) methods. MEG recordings are highly sensitive to metallic interferences originated inside the head by implanted intracranial electrodes, dental prosthesis, etc and also coming from external sources such as pacemakers or vagal stimulators. To reduce these artifacts, a BSS-based fully automatic procedure was recently developed and validated, showing an effective reduction of metallic artifacts in simulated and real signals (Migliorelli et al 2015 J. Neural Eng. 12 046001). The main objective of this study was to evaluate its effects in the detection of IEDs and ECD modeling of patients with focal epilepsy and metallic interference. Approach. A comparison between the resulting positions of ECDs was performed: without removing metallic interference; rejecting only channels with large metallic artifacts; and after BSS-based reduction. Measures of dispersion and distance of ECDs were defined to analyze the results. Main results. The relationship between the artifact-to-signal ratio and ECD fitting showed that higher values of metallic interference produced highly scattered dipoles. Results revealed a significant reduction on dispersion using the BSS-based reduction procedure, yielding feasible locations of ECDs in contrast to the other two approaches. Significance. The automatic BSS-based method can be applied to MEG datasets affected by metallic artifacts as a processing step to improve the localization of epileptic foci.Postprint (published version

Cardiomyocyte marker expression in dogs with left atrial enlargement due to dilated cardiomyopathy or myxomatous mitral valve disease

Introduction. Dilated cardiomyopathy (DCM) and myxomatous mitral valve disease (MMVD) are common heart conditions in dogs. They have different etiology and pathogenesis and although other studies focused on changes in the left ventricles of the affected hearts, the aim of our study was to assess the expressions of some intrinsic proteins in the enlarged left atria. Material and methods. We performed an immunohistochemical analysis of left atrial specimens obtained from 15 dogs with DCM, 35 dogs with MMVD and six control dogs. We assessed the expression of following proteins: SERCA1, SERCA2, sarcomeric actinin, smooth muscle actin, and dystrophin. Results. We noted a higher percentage of SERCA1-positive cells in the MMVD group and lower percentage of dystrophin-positive cells in the DCM group as compared to control group. The expression of other proteins was similar in the hearts of control dogs and dogs with heart diseases. Conclusions. The observed changes in the expression patterns of some proteins in the atria of dogs with DCM and MMVD suggest that atrial enlargement relies not only on volume overload, but also alterations of the intrinsic proteins can contribute to the pathogenesis of dilated cardiomyopathy.

Morphological and immunohistological characteristics of follicular-compact thyroid carcinoma in dog

The case of a 14-year-old mongrel dog with a thyroid tumor treated by thyreoidectomy is described. The resected tumor was subjected to a detailed morphological and immunohistochemical analysis utilizing antibodies directed against thyroglobulin, calcitonin, chromogranin A, cytokeratin 19, thyroid transcription factor-1, CD31, Ki-67 and minichromosome maintenance protein 3. Expression level of the above mentioned antigens allowed to characterize the resected tumor as thyroid follicular-compact carcinoma. Common application of immunohistochemistry may increase the diagnosis precision and efficacy of thyroid tumor treatment in dogs

Left ventricular function after takotsubo is not fully recovered in long-term follow-up: A speckle tracking echocardiography study

Background: Complete improvement of left ventricle (LV) systolic function is an essential feature of takotsubo cardiomyopathy (TTC). It is suggested that 2-dimensional speckle tracking echocardiography (2D STE) can evaluate LV dysfunction more accurately than conventional echocardiography. Thus, the purpose of this research was to assertain whether LV function recovery is complete after the acute phase of TTC using 2D STE commencing 6 to 9 months after discharge. Methods: Thirty patients (29 females, 67 ± 11 years) with an apical ballooning TTC pattern 225.5 ± 27.4 days after their index event were enrolled. The control group consisted of 20 (19 females, 64  ± 9 years) age- and sex-matched volunteers without structural heart disease. Classic echocardiographic parameters, longitudinal strain and LV twist parameters were assessed and compared between the groups. Results: There were no differences in traditional LV systolic, diastolic parameters and in global peak longitudinal strain. In comparison to controls, patients with TTC had lower mean apical rotation (14.4° ± 6.5° vs. 18.3° ± 6.7°; p = 0.048), slower mean peak early diastolic apical rotation rate (–85.1−°/s ± 40.9−°/s vs –119.4−°/s ± 41.9−°/s; p = 0.006) and higher pre-stretch index in the apex (2.16, IQR 0.33–5.50 vs. 0.00, IQR 0.00–2.95, p = 0.008). Conclusions: The improvement of LV function in patients with TTC as assessed by 2D STE may not always be complete. Some residual abnormalities in LV apex function were observed in long-term recovery following TTC episodes.