14 research outputs found
Generalized equilibria for color-gradient lattice Boltzmann model based on higher-order Hermite polynomials: A simplified implementation with central moments
We propose generalized equilibria of a three-dimensional color-gradient
lattice Boltzmann model for two-component two-phase flows using higher-order
Hermite polynomials. Although the resulting equilibrium distribution function,
which includes a sixth-order term on the velocity, is computationally
cumbersome, its equilibrium central moments (CMs) are velocity-independent and
have a simplified form. Numerical experiments show that our approach, as in Wen
et al. [{Phys. Rev. E \textbf{100}, 023301 (2019)}] who consider terms up to
third order, improves the Galilean invariance compared to that of the
conventional approach. Dynamic problems can be solved with high accuracy at a
density ratio of 10; however, the accuracy is still limited to a density ratio
of 1000. For lower density ratios, the generalized equilibria benefit from the
CM-based multiple-relaxation-time model, especially at very high Reynolds
numbers, significantly improving the numerical stability.Comment: 22 pages, 8 figure
Phase Lag Analyses on Ictal Scalp Electroencephalography May Predict Outcomes of Corpus Callosotomy for Epileptic Spasms
Objective: We aimed to clarify the patterns of ictal power and phase lag among bilateral hemispheres on scalp electroencephalography (EEG) recorded pre-operatively during epileptic spasms (ESs) and the correlation with the outcomes following corpus callosotomy.Methods: We enrolled 17 patients who underwent corpus callosotomy for ESs before 20 years of age. After corpus callosotomy, seven patients did not experience further ESs (favorable outcome group), and the remaining 10 patients had ongoing ESs (unfavorable outcome group). We used pre-operative scalp EEG data from monopolar montages using the average reference. The relative power spectrum (PS), ictal power laterality (IPL) among the hemispheres, and phase lag, calculated by the cross-power spectrum (CPS) among symmetrical electrodes (i.e., F3 and F4), were analyzed in the EEG data of ESs from 143 pre-operative scalp video-EEG records. Analyses were conducted separately in each frequency band from the delta, theta, alpha, beta, and gamma range. We compared the means of those data in each patient between favorable and unfavorable outcome groups.Results: Among all frequency bands, no significant differences were seen in the individual mean relative PSs in the favorable and unfavorable outcome group. Although the mean IPLs in each patient tended to be high in the unfavorable outcome group, no significant differences were found. The mean CPSs in the delta, theta, and gamma frequency bands were significantly higher in the unfavorable than in the favorable outcome group. Using the Youden index, the optimal cutoff points of those mean CPS values for unfavorable outcomes were 64.00 in the delta band (sensitivity: 100%, specificity: 80%), 74.20 in the theta band (100, 80%), and 82.05 in the gamma band (100, 80%). Subanalyses indicated that those CPS differences originated from pairs of symmetrical electrodes in the bilateral frontal and temporal areas.Significance: Ictal power and laterality of the ictal power in each frequency band were not associated with the outcomes of CC; however, the phase lags seen in the delta, theta, and gamma frequency bands were larger in the unfavorable than in the favorable outcome group. The phase lags may predict outcomes of CC for ESs on pre-surgical scalp-ictal EEGs
Pyridoxal in the Cerebrospinal Fluid May Be a Better Indicator of Vitamin B6ādependent Epilepsy Than Pyridoxal 5ā²-Phosphate
Background
We aimed to demonstrate the biochemical characteristics of vitamin B6ādependent epilepsy, with a particular focus on pyridoxal 5ā²-phosphate and pyridoxal in the cerebrospinal fluid.
Methods
Using our laboratory database, we identified patients with vitamin B6ādependent epilepsy and extracted their data on the concentrations of pyridoxal 5ā²-phosphate, pyridoxal, pipecolic acid, Ī±-aminoadipic semialdehyde, and monoamine neurotransmitters. We compared the biochemical characteristics of these patients with those of other epilepsy patients with low pyridoxal 5ā²-phosphate concentrations.
Results
We identified seven patients with pyridoxine-dependent epilepsy caused by an ALDH7A1 gene abnormality, two patients with pyridoxal 5ā²-phosphate homeostasis protein deficiency, and 28 patients with other epilepsies with low cerebrospinal fluid pyridoxal 5ā²-phosphate concentrations. Cerebrospinal fluid pyridoxal and pyridoxal 5ā²-phosphate concentrations were low in patients with vitamin B6ādependent epilepsy but cerebrospinal fluid pyridoxal concentrations were not reduced in most patients with other epilepsies with low cerebrospinal fluid pyridoxal 5ā²-phosphate concentrations. Increase in 3-O-methyldopa and 5-hydroxytryptophan was demonstrated in some patients with vitamin B6ādependent epilepsy, suggestive of pyridoxal 5ā²-phosphate deficiency in the brain.
Conclusions
Low cerebrospinal fluid pyridoxal concentrations may be a better indicator of pyridoxal 5ā²-phosphate deficiency in the brain in vitamin B6ādependent epilepsy than low cerebrospinal fluid pyridoxal 5ā²-phosphate concentrations. This finding is especially helpful in individuals with suspected pyridoxal 5ā²-phosphate homeostasis protein deficiency, which does not have known biomarkers
Successful Hemispherotomy in a Patient with Encephalopathy with Continuous Spikes and Waves during Sleep Related to Neonatal Thalamic Hemorrhage: A Case Report with Intracranial Electroencephalogram Findings
Neonatal thalamic hemorrhage is a strong risk factor for developing encephalopathy with continuous spikes and waves during sleep (ECSWS), even when not accompanied by widespread cortical destruction. The efficacy and indication of resective epilepsy surgery in such patients has not yet been reported. A 4-year-old boy was diagnosed with ECSWS based on strong epileptiform activation during sleep and neurocognitive deterioration. He had a history of left thalamic hemorrhage related to a straight sinus thrombosis during the newborn period. He presented with daily absence seizures that were refractory to medical treatment. At age 5, he underwent intracranial electroencephalogram (EEG) recording using depth and subdural strip electrodes placed in the left thalamus and over bilateral cortex, respectively. Interictal and ictal epileptiform discharges were observed in the thalamus, always preceded by discharges in the left or right parietal lobe. Left hemispherotomy successfully normalized the EEG of his unaffected hemisphere and extinguished his seizures. This is the first case report documenting resective epilepsy surgery in a patient with ECSWS due to neonatal thalamic injury without widespread cerebral destruction. Based on intracranial EEG findings, his injured thalamus did not directly generate the EEG abnormalities or absence seizures on its own. Patients with ipsilateral neonatal thalamic injury and even mild lateralized cortical changes may be candidates for resective or disconnective surgery for ECSWS
Usefulness of Endoscopic Transpapillary Tissue Sampling for Malignant Biliary Strictures and Predictive Factors of Diagnostic Accuracy
Background/Aims It is sometimes difficult to distinguish between malignant and benign biliary strictures using imaging studies alone, and pathological diagnosis is necessary. The aim of this study was to determine the usefulness of endoscopic transpapillary tissue sampling and factors predictive of diagnostic accuracy. Methods From April 2008 to December 2014, 136 patients underwent endoscopic transpapillary tissue sampling for malignant biliary strictures. The cytological and histological findings were reported as negative, suspicious, or positive. Suspicious and positive findings were defined as pathologically positive. Results The sensitivity was 65.0% for forceps biopsy, 49.5% for brush cytology, 46.2% for bile aspiration cytology, and 21.9% for endoscopic nasobiliary drainage cytology. The combination of these procedures improved the sensitivity (72.8%). Endoscopic transpapillary tissue sampling was more sensitive for lesions of biliary origin (91.4%) than for extrabiliary lesions (66.3%). In surgical cases, the sensitivity for tumors with an infiltrative growth pattern (53.3%) was significantly lower than for a tumor with an expanding or intermediate growth pattern (87.5%). Conclusions Combining procedures can improve diagnostic accuracy. It may be possible to predict the sensitivity of endoscopic transpapillary tissue sampling by evaluating the etiology and tumor growth pattern using preoperative imaging studies
Synchronous heart rate reduction with suppressionāburst pattern in KCNT1ārelated developmental and epileptic encephalopathies
Abstract Suppressionāburst (SB) is an electroencephalographic pattern observed in neonatalā and infantileāonset developmental and epileptic encephalopathies (DEEs), which are associated with high mortality in early life. However, the relation of SB electroencephalogram (SBāEEG) with autonomic function requires clarification. We investigated the relationship between heart rate (HR) and phasic transition during SBāEEG in DEEs to explore the mechanism of early death. Seven patients (two with KCNT1āDEE) with neonatalā and infantileāonset DEE who presented with SBāEEG were retrospectively identified. Fiveāminute SBāEEGs were analyzed with simultaneous recording of electrocardiograms. Mean HR, suppression duration, and burst period were calculated by measuring RR intervals. Two patients with KCNT1āDEE exhibited synchronous HR fluctuations, with an HR decrease during suppression and an increase during burst. The HR decrease was larger (ā6.1% and ā7.7%) and the median duration of suppression was longer (4.0 and 8.2Ā s) in patients with KCNT1āDEE than the other five (range: ā2.9% to 0.9% and 0.7ā1.7s, respectively). A strong negative correlation was confirmed between suppression duration and HR reduction rates in one patient with KCNT1āDEE. SB phases may influence HR regulation in patients with KCTN1āDEE