Neurovascular networks in epilepsy: Correlating ictal blood perfusion with intracranial electrophysiology.

Perfusion patterns observed in Subtraction Ictal SPECT Co-registered to MRI (SISCOM) assist in focus localization and surgical planning for patients with medically intractable focal epilepsy. While the localizing value of SISCOM has been widely investigated, its relationship to the underlying electrophysiology has not been extensively studied and is therefore not well understood. In the present study, we set to investigate this relationship in a cohort of 70 consecutive patients who underwent ictal and interictal SPECT studies and subsequent stereo-electroencephalography (SEEG) monitoring for localization of the epileptogenic focus and surgical intervention. Seizures recorded during SEEG evaluation (SEEG seizures) were matched to semiologically-similar seizures during the preoperative ictal SPECT evaluation (SPECT seizures) by comparing the semiological changes in the course of each seizure. The spectral changes of the ictal SEEG with respect to interictal ones over 7 traditional frequency bands (0.1 to 150Hz) were analyzed at each SEEG site. Neurovascular (SEEG/SPECT) relations were assessed by comparing the estimated spectral power density changes of the SEEG at each site with the perfusion changes (SISCOM z-scores) estimated from the acquired SISCOM map at that site. Across patients, a significant correlation (p<0.05) was observed between spectral changes during the SEEG seizure and SISCOM perfusion z-scores. Brain sites with high perfusion z-score exhibited higher increased SEEG power in theta to ripple frequency bands with concurrent suppression in delta and theta frequency bands compared to regions with lower perfusion z-score. The dynamics of the correlation of SISCOM perfusion and SEEG spectral power from ictal onset to seizure end and immediate postictal period were also derived. Forty-six (46) of the 70 patients underwent resective epilepsy surgery. SISCOM z-score and power increase in beta to ripple frequency bands were significantly higher in resected than non-resected sites in the patients who were seizure-free following surgery. This study provides for the first time concrete evidence that both hyper-perfusion and hypo-perfusion patterns observed in SISCOM maps have strong electrophysiological underpinnings, and that integration of the information from SISCOM and SEEG can shed light on the location and dynamics of the underlying epileptic brain networks, and thus advance our anatomo-electro-clinical understanding and approaches to targeted diagnostic and therapeutic interventions.

Almost Perfect Metals in One Dimension.

We show that a one-dimensional quantum wire with as few as two channels of interacting fermions can host metallic states of matter that are stable against all perturbations up to qth order in fermion creation or annihilation operators for any fixed finite q. Thus, the leading relevant perturbations are complicated operators that are expected to modify the physics only at very low energies, below accessible temperatures. The stability of these non-Fermi liquid fixed points is due to strong interactions between the channels, which can (but need not) be chosen to be purely repulsive. Our results might enable elementary physical realizations of these phases.

Enhanced stability of C-phycocyanin colorant by extrusion encapsulation.

C-phycocyanin (C-PC) a blue color phycobiliproteins used as a food colorant, therapeutics, medicines, health food and biomarkers. In the present study, morphological property of encapsulated C-PC and its stability under various conditions like temperature, pH conditions are discussed. Microencapsulated droplets formed by extrusion found to be spherical with average size 1.2 ± 0.1 mm. SEM micrographs of freeze dried encapsulate confirmed the spherical shape. The effect of droplet formation with varying alginate percentage (1.5%, 2.0% and 2.5% w/v) was studied. In the stability test at 70 °C and 80 °C relative concentration (CR  %) was found to be 86.89 and 88.19%, respectively. The encapsulated C-PC showed a slow degradation at higher temperature compared to without encapsulated C-PC which was confirmed by UV-visible absorbance. At 45 °C and 55 °C temperatures the stability was studied at various pH conditions (pH 4.5, 5.5, 6.5, and 7.0) and reported. Aggregation of C-PC protein will not change during encapsulation was confirmed by SDS-PAGE. FTIR analysis of encapsulate and the alginate depicted similar characteristics of the compound compared to that of native C-phycocyanin colorant. Microencapsulation improves the stability and increases the shelf life of colorant.

Topological Exciton Fermi Surfaces in Two-Component Fractional Quantized Hall Insulators.

A wide variety of two-dimensional electron systems allow for independent control of the total and relative charge density of two-component fractional quantum Hall (FQH) states. In particular, a recent experiment on bilayer graphene (BLG) observed a continuous transition between a compressible and incompressible phase at total filling ν_{T}=1/2 as charge is transferred between the layers, with the remarkable property that the incompressible phase has a finite interlayer polarizability. We argue that this occurs because the topological order of ν_{T}=1/2 systems supports a novel type of interlayer exciton that carries Fermi statistics. If the fermionic excitons are lower in energy than the conventional bosonic excitons (i.e., electron-hole pairs), they can form an emergent neutral Fermi surface, providing a possible explanation of an incompressible yet polarizable state at ν_{T}=1/2. We perform exact diagonalization studies that demonstrate that fermionic excitons are indeed lower in energy than bosonic excitons. This suggests that a "topological exciton metal" hidden inside a FQH insulator may have been realized experimentally in BLG. We discuss several detection schemes by which the topological exciton metal can be experimentally probed.

Connectivity in ictal single photon emission computed tomography perfusion: a cortico-cortical evoked potential study.

Subtraction ictal and interictal single photon emission computed tomography can demonstrate complex ictal perfusion patterns. Regions with ictal hyperperfusion are suggested to reflect seizure onset and propagation pathways. The significance of ictal hypoperfusion is not well understood. The aim of this study was to verify whether ictal perfusion changes, both hyper- and hypoperfusion, correspond to electrically connected brain networks. A total of 36 subtraction ictal and interictal perfusion studies were analysed in 31 consecutive medically refractory focal epilepsy patients, evaluated by stereo-electroencephalography that demonstrated a single focal onset. Cortico-cortical evoked potential studies were performed after repetitive electrical stimulation of the ictal onset zone. Evoked responses at electrode contacts outside the stimulation site were used as a measure of connectivity. The evoked responses at these electrodes were compared to ictal perfusion values noted at these locations. In 67% of studies, evoked responses were significantly larger in hyperperfused compared to baseline-perfused areas. The majority of hyperperfused contacts also had significantly increased evoked responses relative to pre-stimulus electroencephalogram. In contrast, baseline-perfused and hypoperfused contacts mainly demonstrated non-significant evoked responses. Finally, positive significant correlations (P < 0.05) were found between perfusion scores and evoked responses in 61% of studies. When the stimulated ictal onset area was hyperperfused, 82% of studies demonstrated positive significant correlations. Following stimulation of hyperperfused areas outside seizure onset, positive significant correlations between perfusion changes and evoked responses could be seen, suggesting bidirectional connectivity. We conclude that strong connectivity was demonstrated between the ictal onset zone and hyperperfused regions, while connectivity was weaker in the direction of baseline-perfused or hypoperfused areas. In trying to understand a patient's epilepsy, one should consider the contribution of all hyperperfused regions, as these are likely not random, but represent an electrically connected epileptic network.

Comparing sleep profiles between patients with juvenile myoclonic epilepsy and symptomatic partial epilepsy: Sleep questionnaire-based study.

OBJECTIVES: Patients with epilepsy commonly report excessive daytime sleepiness and daytime fatigue, which may be attributed to the direct effect of seizures, a side effect of antiepileptic drugs or a combination of the two. The aim of the study was to compare sleep profiles in patients with juvenile myoclonic epilepsy (JME) and symptomatic partial epilepsy (PE) in drug naïve and treated patients using standardized sleep questionnaires. METHODS: Three study groups: - 1) juvenile myoclonic epilepsy (N=40) [drug naïve (N=20); On sodium valproate (SVA) (N=20)]; 2) symptomatic partial epilepsy (N=40) [drug naïve (N=20); On carbamazepine (CBZ) (N=20)]; 3) healthy controls (N=40) completed 3 standardized sleep questionnaires - Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, and NIMHANS Comprehensive Sleep Disorders Questionnaire. Scores were compared using t-test and Chi-squared tests (P≤0.005). RESULTS: The mean PSQI scores as well as the proportion of subjects with abnormal PSQI scores were higher in patients with JME and PE compared to controls. Although the mean ESS scores were comparable between patients with epilepsy and controls, the percentage of patients with partial epilepsy having abnormal ESS scores was higher. No significant differences were present between drug naïve and treatment monotherapy groups. Excessive daytime somnolence was reported more often by patients with JME compared to patients with partial epilepsy and controls. CONCLUSION: This study found that patients with epilepsy have a higher prevalence of poor sleep quality compared to controls. Moreover, a significantly higher percentage of patients with partial epilepsy had higher ESS scores compared to healthy controls. However, there was no difference between ESS and PSQI scores between drug naïve and treated patients with JME or PE. SIGNIFICANCE: Poor sleep quality is more prevalent in patients with epilepsy irrespective of the use of antiepileptic medications. Excessive daytime somnolence is more commonly seen in patients with partial epilepsy when compared to the general population.

Floquet Time Crystals.

We define what it means for time translation symmetry to be spontaneously broken in a quantum system and show with analytical arguments and numerical simulations that this occurs in a large class of many-body-localized driven systems with discrete time-translation symmetry.

Complications and oncologic outcomes following elective neck dissection with salvage laryngectomy for the N0 neck.

PURPOSE: To investigate the difference in survival and complication outcomes between patients with a clinically and radiologically N0 neck who received an elective neck dissection at the time of salvage total laryngectomy compared to those who had salvage total laryngectomy alone. MATERIALS AND METHODS: A retrospective chart review was performed on 125 salvage total laryngectomy patients who were clinically and radiologically N0 preoperatively. Performance of an elective neck dissection and other factors were tested for associations with various postoperative complications, disease-free survival, and overall survival. RESULTS: Ninety-eight patients underwent elective neck dissection, of which ten had positive nodal pathology. Elective neck dissection was not significantly associated with complications or survival outcomes. Positive nodal disease was associated with worse disease-free and overall survival on multivariate analysis. CONCLUSIONS: In patients with clinically and radiologically N0 necks undergoing salvage total laryngectomy, an elective neck dissection can provide prognostic information but does not appear to be significantly associated with increased complications or improved survival.

Lack of heart rate variability during apnea in patients with juvenile myoclonic epilepsy (JME).

PURPOSE: Apneas occurring during sleep may precipitate autonomic instability in epilepsy patients making them susceptible to sudden death (SUDEP). Literature on heart rate variability (HRV) during apnea among patients with juvenile myoclonic epilepsy (JME) is sparse. The aim was to characterize the HRV during the peri-apneic/hypopneic period in patients with JME. METHODS: Overnight polysomnography of 25 patients with JME (M/F = 14:11; mean age, 21.28 ± 4.34 years) and 25 gender-matched healthy controls (M/F = 11:14; mean age, 23.32 ± 3.68 years) were analyzed. In both patients and controls, the time domain, frequency domain, and nonlinear HRV indices were analyzed for two minutes before and after apnea/hypopnea termination and compared using paired t test (p ≤ 0.05). Additionally, the changes in HRV parameters in the peri-apnea/hypopnea period were compared between the two groups using independent samples t test (p ≤ 0.05). RESULTS: In controls, there was a significant decrease of mean RR interval (p = 0.029) and a significant increase of standard deviation of RR interval (SDNN; p = 0.046) in the post-apneic/hypopneic period as compared with the pre-apneic/hypopneic period. Analysis using nonlinear measures showed a significant increase in the long-term HRV (p = 0.042) in the post-apnea period, but a comparable short-term HRV (p = 0.266). Conversely, in JME, all the HRV parameters, including nonlinear measures were comparable in the pre- and post-apneic/hypopneic period. Finally, comparison of the changes in HRV parameters in the peri-apnea/hypopnea period in patients with JME and healthy controls showed significant differences in SDNN (p = 0.026) and long-term HRV (p = 0.018). CONCLUSIONS: This study showed that there was a lack of apnea-mediated HRV changes, including long-term HRV changes in patients with JME. This might suggest an alteration in reflex baroreceptor activation in patients with JME, which might explain the vulnerability for SUDEP in patients with epilepsy.

Single step aqueous two-phase extraction for downstream processing of C-phycocyanin from Spirulina platensis.

C-phycocyanin, a natural food colorant, is gaining importance worldwide due to its several medical and pharmaceutical applications. In the present study, aqueous two-phase extraction was shown to be an attractive alternative for the downstream processing of C-phycocyanin from Spirulina platensis. By employing differential partitioning, C-phycocyanin selectively partitioned to the polymer rich (top) phase in concentrated form and contaminant proteins to the salt rich (bottom) phase. This resulted in an increase in the product purity (without losing much of the yield) in a single step without the need of multiple processing steps. Effect of process parameters such as molecular weight, tie line length, phase volume ratio, concentration of phase components on the partitioning behavior of C-phycocyanin was studied. The results were explained based on relative free volume of the phase systems. C-phycocyanin with a purity of 4.32 and yield of about 79 % was obtained at the standardized conditions.

Effects of Landau level mixing on the fractional quantum Hall effect in monolayer graphene.

We report results of exact diagonalization studies of the spin- and valley-polarized fractional quantum Hall effect in the N = 0 and N = 1 Landau levels in graphene. We use an effective model that incorporates Landau level mixing to lowest order in the parameter κ = ((e(2)/εℓ)/(hv(F)/ℓ)) = (e(2)/εv(F)h), which is magnetic field independent and can only be varied through the choice of substrate. We find Landau level mixing effects are negligible in the N = 0 Landau level for κ ≲ 2. In fact, the lowest Landau level projected Coulomb Hamiltonian is a better approximation to the real Hamiltonian for graphene than it is for semiconductor based quantum wells. Consequently, the principal fractional quantum Hall states are expected in the N = 0 Landau level over this range of κ. In the N = 1 Landau level, fractional quantum Hall states are expected for a smaller range of κ and Landau level mixing strongly breaks particle-hole symmetry, producing qualitatively different results compared to the N = 0 Landau level. At half filling of the N = 1 Landau level, we predict the anti-Pfaffian state will occur for κ ∼ 0.25-0.75.

Deep neck abscess after intubation trauma: a case report.

Significant injuries from endotracheal intubation are exceedingly rare but can lead to life-threatening complications, such as pharyngeal perforation. This type of perforation can result in abscess formation and airway compromise. Risks for this complication include operator skill and intubation in emergent situations. This case report details a 59-year-old male who underwent elective septoplasty with bilateral nasal turbinate reduction. The procedure required general anesthesia induction and endotracheal intubation. He developed a gradually enlarging right-sided neck mass with associated fevers, neck pain, odynophagia, and dysphonia. He presented to the emergency department on postoperative day 5 and was diagnosed with a right-sided, prevertebral space abscess with airway mass effect secondary to pharyngeal perforation. He was admitted for operative management, intravenous antibiotics, and was successfully treated. While significant injury from endotracheal intubation is rare, it can result in infection and threaten airway patency. Emergency physicians must recognize pharyngeal perforation as a potential source of infection following instrumentation of the pharynx. This case has been reported to increase awareness of the potential for such injury.

Numerical calculation of the neutral fermion gap at the ν=5/2 fractional quantum Hall state.

We present the first numerical computation of the neutral fermion gap, Δ(F), in the ν=5/2 quantum Hall state, which is analogous to the energy gap for a Bogoliubov-de Gennes quasiparticle in a superconductor. We find Δ(F)≈0.027e(2)/εℓ(0), comparable to the charge gap. We also deduce an effective Fermi velocity v(F) for neutral fermions from the low-energy spectra for odd numbers of electrons, and thereby obtain a correlation length ξ(F)=v(F)/Δ(F)≈1.3ℓ(0). We comment on implications for experiments, topological quantum information processing, and electronic mechanisms of superconductivity.

Practicality and cost-effectiveness of using MRI compatible EEG system in the critical care setting.

BACKGROUND: Continuous video-EEG (cvEEG) monitoring is a vastly utilized tool for monitoring critically ill patients in the intensive care unit. Our study investigates the clinical utility and cost-effectiveness of using MRI Compatible EEG electrode system for patients being monitored in the intensive care unit. METHODS: This retrospective study included 14 critically ill patients who underwent cvEEG between March 2019 to March 2020. They were classified into 2 subgroups: Group 1- 'MRI-compatible EEG' (mean age: 56.00 ± 19.99 years; M:F = 2:5; N = 7), Group 2 - 'Conventional EEG' (mean age: 49.14 ± 24.76 years; M:F = 4:3; N = 7). The EEG monitoring times as well as cost-effectiveness of cvEEG between the groups were compared using Mann-Whitney Test (p ≤ 0.05). We also compared the MRI quality between the groups using Chi-squared test (p ≤ 0.05). RESULTS: The EEG non-monitored time in Group 2 (7.62 ± 6.45 h) was significantly higher than Group 1 (2.71 ± 2.34 h)] (p = 0.025). The average daily cost for cvEEG in Group 1 ($2098.53 ± 493.58) and Group 2 ($2230.58 ± 142.73) was comparable (p = 0.896). The quality of MRI scans between Group 1 (6/7) and 2 (6/7) were also comparable (p = 1.000). CONCLUSIONS: The monitoring time lost in patients with MRI Compatible EEG electrodes was significantly lower than the patients with Conventional EEG electrodes. The daily cost of monitoring and the quality of MRI scans were comparable between the 2 groups. We conclude that the use of MRI Compatible EEG electrodes is a practical and cost-effective method to improve the quality of monitoring in critically ill patients.

Sleep profile and Polysomnography in patients with drug-resistant temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS) and the effect of epilepsy surgery on sleep-a prospective cohort study.

OBJECTIVES: We analyzed changes in sleep profile and architecture of patients with drug-resistant TLE-HS using three validated sleep questionnaires- Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), NIMHANS Comprehensive Sleep Disorders, and polysomnography (PSG). We studied the effect of epilepsy surgery in a subset of patients. METHODS: In this prospective observational cohort study, sleep profile of 40 patients with drug-resistant TLE-HS was compared to 40 healthy matched controls. Sleep architecture of 22 patients was studied by overnight PSG and compared to 22 matched controls. Sleep profile was reassessed in 20 patients after a minimum period of three months after epilepsy surgery. RESULTS: The mean PSQI was higher among patients compared to controls(P=0.0004) while mean ESS showed no difference. NCSDQ showed fewer patients feeling refreshed after a night's sleep compared to controls (p=0.006). PSG revealed a higher time in bed (p=0.0001), longer total sleep time (p=0.006) and more time spent in NREM stage 1 (p=0.001) and stage 2 (p=0.005) while spending less time in stage 3 (p=0.039) among TLE patients. Sleep efficiency was worse in patients on ≥3 ASMs compared to those on 2 ASMs (p-0.044). There was no change in mean ESS (p=0.48) or PSQI (p=0.105) after surgery. CONCLUSIONS: Patients with drug-resistant TLE-HS have an altered sleep profile and architecture. Patients on ≥3 ASMs have a lower sleep efficiency. Reassessment at short intervals after epilepsy surgery did not reveal significant changes in sleep profile.

Implementing arbitrary phase gates with Ising anyons.

Ising-type non-Abelian anyons are likely to occur in a number of physical systems, including quantum Hall systems, where recent experiments support their existence. In general, non-Abelian anyons may be utilized to provide a topologically error-protected medium for quantum information processing. However, the topologically protected operations that may be obtained by braiding and measuring topological charge of Ising anyons are precisely the Clifford gates, which are not computationally universal. The Clifford gate set can be made universal by supplementing it with single-qubit pi/8-phase gates. We propose a method of implementing arbitrary single-qubit phase gates for Ising anyons by running a current of anyons with interfering paths around computational anyons.

Cutaneous Carcinosarcoma: A Small Case Series and Review of the Literature of a Rare Skin Tumor.

Carcinosarcomas are composed of epithelial and mesenchymal elements and primarily present within visceral organs. Despite being potentially aggressive, they are a rare diagnosis in the skin, and few manifestations have been reported to date. In this report, we describe two separate cases of carcinosarcoma presenting as nonhealing scalp wounds. Patient A: a 57-year-old male with a nonhealing skin lesion of ten years successfully treated with wide-local excision and local ortichochea flap reconstruction. Patient B: a 75-year-old female that presented with a painless, slow-growing hemorrhagic mass of 7 years invading the skull and dura ultimately requiring craniectomy and free-tissue transfer with anterolateral thigh flap. Cutaneous carcinosarcomas have more favorable outcomes due to low metastatic rates likely due to earlier detection, but delayed presentation can be fatal. Histopathological analysis is critical for determining diagnosis and prognosis. Adequate reconstruction after wide base excision varies and follows the reconstructive ladder/elevator ranging from primary closure up through free-tissue transfer. With cutaneous manifestations of carcinosarcoma seldom reported in the literature, it is our hope that reporting unusual instances such as this will raise awareness and allow for earlier diagnoses, treatments, and reconstructions.