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https://www.readbyqxmd.com/read/29113719/utilization-of-independent-component-analysis-for-accurate-pathological-ripple-detection-in-intracranial-eeg-recordings-recorded-extra-and-intra-operatively
#1
Shoichi Shimamoto, Zachary J Waldman, Iren Orosz, Inkyung Song, Anatol Bragin, Itzhak Fried, Jerome Engel, Richard Staba, Ashwini Sharan, Chengyuan Wu, Michael R Sperling, Shennan A Weiss
OBJECTIVE: To develop and validate a detector that identifies ripple (80-200 Hz) events in intracranial EEG (iEEG) recordings in a referential montage and utilizes independent component analysis (ICA) to eliminate or reduce high-frequency artifact contamination. Also, investigate the correspondence of detected ripples and the seizure onset zone (SOZ). METHODS: iEEG recordings from 16 patients were first band-pass filtered (80-600 Hz) and Infomax ICA was next applied to derive the first independent component (IC1)...
October 25, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29111591/magnetoencephalographic-imaging-of-ictal-high-frequency-oscillations-80-200%C3%A2-hz-in-pharmacologically-resistant-focal-epilepsy
#2
Jayabal Velmurugan, Srikantan S Nagarajan, Narayanan Mariyappa, Shankar G Ravi, Kandavel Thennarasu, Ravindranadh C Mundlamuri, Kenchaiah Raghavendra, Rose Dawn Bharath, Jitender Saini, Arimappamagan Arivazhagan, Jamuna Rajan, Anita Mahadevan, Malla B Rao, Parthasarathy Satishchandra, Sanjib Sinha
OBJECTIVE: Specificity of ictal high-frequency oscillations (HFOs) in identifying epileptogenic abnormality is significant, compared to the spikes and interictal HFOs. The objectives of the study were to detect and to localize ictal HFOs by magnetoencephalography (MEG) for identifying the seizure onset zone (SOZ), evaluate the cortical excitability from preictal to ictal transition, and establish HFO concordance rates with other modalities and postsurgical resection. METHODS: Sixty-seven patients with drug-resistant epilepsy had at least 1 spontaneous seizure each during MEG acquisition, and analysis was carried out on 20 seizures from 20 patients...
November 7, 2017: Epilepsia
https://www.readbyqxmd.com/read/29102181/microwave-digestion-assisted-hfo-biochar-adsorption-to-recover-phosphorus-from-swine-manure
#3
Tao Zhang, Haoyu Xu, Huanhuan Li, Xinyue He, Yuanji Shi, Andrea Kruse
A sustainable management option for dealing with waste straw is to pyrolyze it to create biochar, which can then be used as a sorbent in pollution treatments, such as the recovery of phosphorus (P) from swine manure. However, the inability to directly capture soluble organic P (OP) and sparingly soluble P and the low selectivity of biochar remain key issues in this process. To overcome these, we investigated a microwave (MW) digestion pretreatment with a HFO/biochar adsorption process. The MW digestion-assisted treatment showed good performance for the solubilization of OP and sparingly soluble P...
October 25, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29099197/electronic-stopping-of-slow-protons-in-oxides-scaling-properties
#4
D Roth, B Bruckner, G Undeutsch, V Paneta, A I Mardare, C L McGahan, M Dosmailov, J I Juaristi, M Alducin, J D Pedarnig, R F Haglund, D Primetzhofer, P Bauer
Electronic stopping of slow protons in ZnO, VO_{2} (metal and semiconductor phases), HfO_{2}, and Ta_{2}O_{5} was investigated experimentally. As a comparison of the resulting stopping cross sections (SCS) to data for Al_{2}O_{3} and SiO_{2} reveals, electronic stopping of slow protons does not correlate with electronic properties of the specific material such as band gap energies. Instead, the oxygen 2p states are decisive, as corroborated by density functional theory calculations of the electronic densities of states...
October 20, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29079354/effect-of-luting-agent-on-the-load-to-failure-and-accelerated-fatigue-resistance-of-lithium-disilicate-laminate-veneers
#5
Marco M M Gresnigt, Mutlu Özcan, Marco Carvalho, Priscilla Lazari, Marco S Cune, Peywand Razavi, Pascal Magne
OBJECTIVE: The aim of this study was to investigate the influence of the luting agent on the application of laminate veneers (LVs) in an accelerated fatigue and load-to-failure test after thermo-cyclic aging. METHODS: Sound maxillary central incisors (N=40) were randomly divided into four groups to receive LVs (Li2Si2O5) that were adhesively bonded: Group CEMF: Adhesive cement (Variolink Esthetic LC), fatigue test; Group CEMLF: Adhesive cement, load-to-failure test; Group COMF: Resin composite (Enamel HFO), fatigue test; Group COMLF: Resin composite, load-to-failure test...
October 24, 2017: Dental Materials: Official Publication of the Academy of Dental Materials
https://www.readbyqxmd.com/read/29062105/resection-of-high-frequency-oscillations-predicts-seizure-outcome-in-the-individual-patient
#6
Tommaso Fedele, Sergey Burnos, Ece Boran, Niklaus Krayenbühl, Peter Hilfiker, Thomas Grunwald, Johannes Sarnthein
High frequency oscillations (HFOs) are recognized as biomarkers for epileptogenic brain tissue. A remaining challenge for epilepsy surgery is the prospective classification of tissue sampled by individual electrode contacts. We analysed long-term invasive recordings of 20 consecutive patients who subsequently underwent epilepsy surgery. HFOs were defined prospectively by a previously validated, automated algorithm in the ripple (80-250 Hz) and the fast ripple (FR, 250-500 Hz) frequency band. Contacts with the highest rate of ripples co-occurring with FR over several five-minute time intervals designated the HFO area...
October 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29060055/a-novel-hfo-based-method-for-unsupervised-localization-of-the-seizure-onset-zone-in-drug-resistant-epilepsy
#7
Paige M Murphy, Adam J von Paternos, Sabato Santaniello
High frequency oscillations (HFOs) are potential biomarkers of epileptic areas. In patients with drug-resistant epilepsy, HFO rates tend to be higher in the seizure onset zone (SOZ) than in other brain regions and the resection of HFO-generating areas positively correlates with seizure-free surgery outcome. Nonetheless, the development of robust unsupervised HFO-based tools for SOZ localization remains challenging. Current approaches predict the SOZ by processing small samples of intracranial EEG (iEEG) data and applying patient-specific thresholds on the HFO rate...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28992690/atmospheric-chemistry-of-e-and-z-cf3ch%C3%A2-chf-hfo-1234ze-oh-reaction-kinetics-as-a-function-of-temperature-and-uv-and-ir-absorption-cross-sections
#8
María Antiñolo, Iván Bravo, Elena Jiménez, Bernabé Ballesteros, José Albaladejo
We report here the rate coefficients for the OH reactions (kOH) with E-CF3CH═CHF and Z-CF3CH═CHF, potential substitutes of HFC-134a, as a function of temperature (263-358 K) and pressure (45-300 Torr) by pulsed laser photolysis coupled to laser-induced fluorescence techniques. For the E-isomer, the existing discrepancy among previous results on the T dependence of kOH needs to be elucidated. For the Z-isomer, this work constitutes the first absolute determination of kOH. No pressure dependence of kOH was observed, while kOH exhibits a non-Arrhenius behavior: kOH(E) = [Formula: see text] and kOH(Z) = [Formula: see text] cm(3) molecule(-1) s(-1), where uncertainties are 2σ...
October 20, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28987533/joint-approximate-diagonalization-of-eigenmatrices-jade-as-a-high-throughput-approach-for-analysis-of-hyphenated-and-comprehensive-two-dimensional-gas-chromatographic-data
#9
Maryam Zarghani, Hadi Parastar
The objective of the present work is development of joint approximate diagonalization of eigenmatrices (JADE) as a member of independent component analysis (ICA) family, for the analysis of gas chromatography-mass spectrometry (GC-MS) and comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) data to address incomplete separation problem occurred during the analysis of complex sample matrices. In this regard, simulated GC-MS and GC×GC-MS data sets with different number of components, different degree of overlap and noise were evaluated...
September 27, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28981989/consecutive-transformations-of-tetrafluoropropenes-hydrogermylation-and-catalytic-c-f-activation-steps-at-a-lewis-acidic-aluminium-fluoride
#10
Thomas Braun, Gisa Meißner, Erhard Kemnitz, Konrad Kretschmar
Functionalization reactions of the refrigerants HFO 1234yf (2,3,3,3-tetrafluoropropene) and HFO-1234ze (1,3,3,3-tetrafluoropropene) were developed. The selectivity and reactivity towards CF3 groups of C-F activation reactions can be controlled by either employing a germane or silane as hydrogen source. Unique transformations were designed to accomplish consecutive hydrogermylation and C-F activation steps. This allows for an unprecedented transformation of an olefinic C-F bond into a C-H bond by heterogeneous catalysis...
October 5, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28922535/power-and-coherence-of-cortical-high-frequency-oscillations-during-wakefulness-and-sleep
#11
Matías Cavelli, Daniel Rojas-Líbano, Natalia Schwarzkopf, Santiago Castro-Zaballa, Joaquín Gonzalez, Alejandra Mondino, Noelia Santana, Luciana Benedetto, Atilio Falconi, Pablo Torterolo
Recently, a novel type of fast cortical oscillatory activity that occurs between 110 and 160 Hz (high-frequency oscillations (HFO)) was described. HFO are modulated by the theta rhythm in hippocampus and neocortex during active wakefulness and REM sleep. As theta-HFO coupling increases during REM, a role for HFO in memory consolidation has been proposed. However, global properties such as the cortex-wide topographic distribution and the cortico-cortical coherence remain unknown. In this study, we recorded the electroencephalogram during sleep and wakefulness in the rat and analyzed the spatial extent of the HFO band power and coherence...
September 18, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28860077/the-cs-algorithm-a-novel-method-for-high-frequency-oscillation-detection-in-eeg
#12
Jan Cimbálník, Angela Hewitt, Greg Worrell, Matt Stead
BACKGROUND: High frequency oscillations (HFOs) are emerging as potentially clinically important biomarkers for localizing seizure generating regions in epileptic brain. These events, however, are too frequent, and occur on too small a time scale to be identified quickly or reliably by human reviewers. Many of the deficiencies of the HFO detection algorithms published to date are addressed by the CS algorithm presented here. NEW METHOD: The algorithm employs novel methods for: 1) normalization; 2) storage of parameters to model human expertise; 3) differentiating highly localized oscillations from filtering phenomena; and 4) defining temporal extents of detected events...
August 30, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28794978/localization-of-beta-and-high-frequency-oscillations-within-the-subthalamic-nucleus-region
#13
B C M van Wijk, A Pogosyan, M I Hariz, H Akram, T Foltynie, P Limousin, A Horn, S Ewert, P Brown, V Litvak
Parkinsonian bradykinesia and rigidity are typically associated with excessive beta band oscillations in the subthalamic nucleus. Recently another spectral peak has been identified that might be implicated in the pathophysiology of the disease: high-frequency oscillations (HFO) within the 150-400 Hz range. Beta-HFO phase-amplitude coupling (PAC) has been found to correlate with severity of motor impairment. However, the neuronal origin of HFO and its usefulness as a potential target for deep brain stimulation remain to be established...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28748408/a-simple-statistical-method-for-the-automatic-detection-of-ripples-in-human-intracranial-eeg
#14
K Charupanit, B A Lopour
High frequency oscillations (HFOs) are a promising biomarker of epileptic tissue, but detection of these electrographic events remains a challenge. Automatic detectors show encouraging results, but they typically require optimization of multiple parameters, which is a barrier to good performance and broad applicability. We therefore propose a new automatic HFO detection algorithm, focusing on simplicity and ease of implementation. It requires tuning of only an amplitude threshold, which can be determined by an iterative process or directly calculated from statistics of the rectified filtered data (i...
July 26, 2017: Brain Topography
https://www.readbyqxmd.com/read/28718452/role-of-al-doping-in-the-filament-disruption-in-hfo2-resistance-switches
#15
Stefano Brivio, Jacopo Frascaroli, Sabina Spiga
Resistance switching devices, whose operation is driven by formation (SET) and dissolution (RESET) of conductive paths shorting and disconnecting the two metal electrodes, have recently received great attention and a deep general comprehension of their operation has been achieved. However, the link between switching characteristics and material properties is still quite weak. In particular, doping of the switching oxide layer has often been investigated only for looking at performance upgrade and rarely for a meticulous investigation of the switching mechanism...
July 18, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28709992/time-dependent-evolution-of-seizures-in-a-model-of-mesial-temporal-lobe-epilepsy
#16
Charles Behr, Maxime Lévesque, Thomas Stroh, Massimo Avoli
Low-voltage fast (LVF) and hypersynchronous (HYP) - onset seizures occur in the EEG obtained with depth electrodes from mesial temporal lobe epilepsy (MTLE) patients and animal models. In epileptic rats analyzed up to approximately two weeks after pilocarpine-induced status epilepticus (SE), these patterns are associated with specific high-frequency oscillation (HFO) content: ripples (80-200Hz) or fast-ripples (250-500Hz) predominate in LVF or HYP seizures, respectively. To establish whether these features change over the course of the disease, we recorded the EEG from the hippocampal CA3 subfield, subiculum, entorhinal cortex and dentate gyrus in two groups of pilocarpine-treated rats: the "early stage group" (n=8) was analyzed from day 3 to 20 post-SE while the "late stage group" (n=7) was studied from day 27 to 53 post-SE...
October 2017: Neurobiology of Disease
https://www.readbyqxmd.com/read/28681378/update-on-the-mechanisms-and-roles-of-high-frequency-oscillations-in-seizures-and-epileptic-disorders
#17
REVIEW
Premysl Jiruska, Catalina Alvarado-Rojas, Catherine A Schevon, Richard Staba, William Stacey, Fabrice Wendling, Massimo Avoli
High-frequency oscillations (HFOs) are a type of brain activity that is recorded from brain regions capable of generating seizures. Because of the close association of HFOs with epileptogenic tissue and ictogenesis, understanding their cellular and network mechanisms could provide valuable information about the organization of epileptogenic networks and how seizures emerge from the abnormal activity of these networks. In this review, we summarize the most recent advances in the field of HFOs and provide a critical evaluation of new observations within the context of already established knowledge...
August 2017: Epilepsia
https://www.readbyqxmd.com/read/28676240/local-nmda-receptor-hypofunction-evokes-generalized-effects-on-gamma-and-high-frequency-oscillations-and-behavior
#18
Jaime Lee, Matthew R Hudson, Terence J O'Brien, Jess Nithianantharajah, Nigel C Jones
The NMDA receptor (NMDAr) hypofunction theory of schizophrenia suggests that aberrant signaling through NMDAr underlies the pathophysiology of this disease. This is commonly modeled in rodents via treatment with NMDAr antagonists, which causes a range of behavioral effects that represent endophenotypes related to schizophrenia. These drugs also disrupt high-frequency neural oscillations within the brain, also potentially relevant to disease. We studied the effect of localized NMDAr hypofunction on the generation of neural oscillations occurring both locally and in distant brain regions, and on behaviors routinely used as endophenotypes to model psychosis in rodents...
July 1, 2017: Neuroscience
https://www.readbyqxmd.com/read/28669244/automated-detector-of-high-frequency-oscillations-in-epilepsy-based-on-maximum-distributed-peak-points
#19
Guo-Ping Ren, Jia-Qing Yan, Zhi-Xin Yu, Dan Wang, Xiao-Nan Li, Shan-Shan Mei, Jin-Dong Dai, Xiao-Li Li, Yun-Lin Li, Xiao-Fei Wang, Xiao-Feng Yang
High frequency oscillations (HFOs) are considered as biomarker for epileptogenicity. Reliable automation of HFOs detection is necessary for rapid and objective analysis, and is determined by accurate computation of the baseline. Although most existing automated detectors measure baseline accurately in channels with rare HFOs, they lose accuracy in channels with frequent HFOs. Here, we proposed a novel algorithm using the maximum distributed peak points method to improve baseline determination accuracy in channels with wide HFOs activity ranges and calculate a dynamic baseline...
April 17, 2017: International Journal of Neural Systems
https://www.readbyqxmd.com/read/28666056/high-frequency-oscillations-the-state-of-clinical-research
#20
REVIEW
Birgit Frauscher, Fabrice Bartolomei, Katsuhiro Kobayashi, Jan Cimbalnik, Maryse A van 't Klooster, Stefan Rampp, Hiroshi Otsubo, Yvonne Höller, Joyce Y Wu, Eishi Asano, Jerome Engel, Philippe Kahane, Julia Jacobs, Jean Gotman
Modern electroencephalographic (EEG) technology contributed to the appreciation that the EEG signal outside the classical Berger frequency band contains important information. In epilepsy, research of the past decade focused particularly on interictal high-frequency oscillations (HFOs) > 80 Hz. The first large application of HFOs was in the context of epilepsy surgery. This is now followed by other applications such as assessment of epilepsy severity and monitoring of antiepileptic therapy. This article reviews the evidence on the clinical use of HFOs in epilepsy with an emphasis on the latest developments...
August 2017: Epilepsia
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