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https://www.readbyqxmd.com/read/28198591/interpenetrating-conducting-hydrogel-materials-for-neural-interfacing-electrodes
#1
Josef Goding, Aaron Gilmour, Penny Martens, Laura Poole-Warren, Rylie Green
Conducting hydrogels (CHs) are an emerging technology in the field of medical electrodes and brain-machine interfaces. The greatest challenge to the fabrication of CH electrodes is the hybridization of dissimilar polymers (conductive polymer and hydrogel) to ensure the formation of interpenetrating polymer networks (IPN) required to achieve both soft and electroactive materials. A new hydrogel system is developed that enables tailored placement of covalently immobilized dopant groups within the hydrogel matrix...
February 15, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28195489/composition-and-stability-of-plasma-polymer-films-exhibiting-vertical-chemical-gradients
#2
Patrick Rupper, Marianne Vandenbossche, Laetitia Bernard, Dirk Hegemann, Manfred P Heuberger
Controlling the balance between stability and functional group density in grown plasma polymer films is the key to diverse applications such as drug release, tissue-engineered implants, filtration, contact lenses, microfluidics, electrodes, sensors, etc. Highly functional plasma polymer films typically show a limited stability in air or aqueous environments due to mechanisms like molecular reorganization, oxidation and hydrolysis. Stabilization is achieved by enhancing cross-linking at the cost of the terminal functional groups such as -OH and -COOH, but also -NH2 etc...
February 14, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28195372/conjugated-polymer-blends-for-organic-photovoltaics-rational-control-of-vertical-stratification-for-high-performance
#3
REVIEW
Yu Yan, Xuan Liu, Tao Wang
The photoactive layer of bulk-heterojunction organic solar cells, in a thickness range of tens to hundreds of nanometers, comprises phase-separated electron donors and acceptors after solution casting. The component distribution in the cross-section of these thin films is found to be heterogeneous, with electron donors or acceptors accumulated or depleted near the electrode interfaces. This vertical stratification of the photovoltaic blend influences device metrics through its impact on charge transport and recombination, and consequently plays an important role in determining the power conversion efficiency of photovoltaic devices...
February 13, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28194649/numerical-modeling-of-percutaneous-auricular-vagus-nerve-stimulation-a-realistic-3d-model-to-evaluate-sensitivity-of-neural-activation-to-electrode-position
#4
Amine M Samoudi, Stefan Kampusch, Emmeric Tanghe, Jozsef C Széles, Luc Martens, Eugenijus Kaniusas, Wout Joseph
OBJECTIVE: Percutaneous stimulation of the auricular branch of the vagus nerve (pVNS) by miniaturized needle electrodes in the auricle gained importance as a treatment for acute and chronic pain. The objective is to establish a realistic numerical model of pVNS and investigate the effects of stimulation waveform, electrodes' depth, and electrodes' position on nerve excitation threshold and the percentage of stimulated nerves. METHODS: Simulations were performed with Sim4Life...
February 13, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28187794/continuous-eeg-monitoring-in-the-intensive-care-unit
#5
G B Young, J Mantia
The purpose and indications for continuous electroencephalography monitoring (CEEG) in intensive care unit (ICU) patients include seizure detection, monitoring the effects of treatment (including depth of sedation), grading and classification of EEG abnormalities, ischemia detection and prognostication. Practical considerations of ICU CEEG include: choice of montages (patterns of electrode placement and connections), EEG electrodes, recognition of artifacts, and the use of automated or computerized analysis...
2017: Handbook of Clinical Neurology
https://www.readbyqxmd.com/read/28185968/the-value-of-diagnostic-bilateral-intracranial-eeg-in-treatment-resistant-focal-epilepsy
#6
Travis C Hill, Benjamin A Rubin, Vineet Tyagi, Jason Theobald, Alyson Silverberg, Mary Miceli, Patricia Dugan, Chad Carlson, Werner K Doyle
OBJECTIVES: We assessed the efficacy and risks of diagnostic bilateral intracranial EEG (bICEEG) in treatment-resistant epilepsy (TRE) patients with poorly lateralized epileptogenic zone (EZ) on non-invasive studies as reflected by progress to resection, Engel outcome and complication rate. METHODS: This is a retrospective chart review of 199 patients with TRE who had diagnostic bICEEG at New York University Medical Center between 1994 and 2013. Study endpoints were progress to resection, surgical outcome and perioperative complications...
February 6, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28185967/intraoperative-ct-and-nexframe-guided-placement-of-bilateral-hippocampal-based-responsive-neurostimulation-a-technical-note
#7
Kunal Gupta, Jeffrey S Raskin, Ahmed M Raslan
INTRODUCTION: Surgical resection of a lesion that correlates with seizure onset in patients with epilepsy can dramatically improve seizure burden and quality of life. For bilateral hippocampal lesions, bilateral resection comes with a risk of severe cognitive deficits. Responsive neurostimulation (RNS) devices offers a new modality to treat multifocal lesions in a reversible manner, including bilateral hippocampal stimulation. We describe technical aspects of Nexframe-assisted placement of bilateral NeuroPace mesial temporal electrodes, and case examples...
February 6, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28178740/-impact-of-the-overlap-region-between-acoustic-and-electric-stimulation
#8
Uwe Baumann, Moritz Mocka
Patients with residual hearing in the low frequencies and ski-slope hearing loss with partial deafness at medium and high frequencies receive a cochlear implant treatment with electric-acoustic stimulation (EAS, "hybrid" stimulation). In the border region between electric and acoustic stimulation a superposition of the 2 types of stimulation is expected. The area of overlap is determined by the insertion depth of the stimulating electrode and the lower starting point of signal transmission provided by the CI speech processor...
February 8, 2017: Laryngo- Rhino- Otologie
https://www.readbyqxmd.com/read/28177176/electroencephalographic-discontinuity-during-sevoflurane-anesthesia-in-infants-and-children
#9
Laura Cornelissen, Ann M Bergin, Kimberly Lobo, Carolina Donado, Janet S Soul, Charles B Berde
BACKGROUND: Deep anesthesia in adults may be associated with electroencephalographic (EEG) suppression and higher rates of postoperative complications. Little is known about the impact of anesthetic depth on short- or long-term outcomes in pediatrics. Brain activity monitoring may complement clinical signs of anesthetic depth. This prospective observational study aimed to assess the frequency and degree of profound EEG suppression using multichannel EEG in children during sevoflurane general anesthesia...
February 8, 2017: Paediatric Anaesthesia
https://www.readbyqxmd.com/read/28175482/203%C3%A2-insular-depth-electrode-in-pediatric-treatment-refractory-epilepsy
#10
Luke Tomycz, Ali Haider, Maura Hamilton, David B Clarke, Mark R Lee
No abstract text is available yet for this article.
August 1, 2016: Neurosurgery
https://www.readbyqxmd.com/read/28169833/measurements-and-models-of-electric-fields-in-the-in-vivo-human-brain-during-transcranial-electric-stimulation
#11
Yu Huang, Anli A Liu, Belen Lafon, Daniel Friedman, Michael Dayan, Xiuyuan Wang, Marom Bikson, Werner K Doyle, Orrin Devinsky, Lucas C Parra
Transcranial electric stimulation aims to stimulate the brain by applying weak electrical currents at the scalp. However, the magnitude and spatial distribution of electric fields in the human brain are unknown. We measured electric potentials intracranially in ten epilepsy patients and estimate electric fields across the entire brain by leveraging calibrated current-flow models. When stimulating at 2 mA, cortical electric fields reach 0.4 V/m, the lower limit of effectiveness in animal studies. When individual whole-head anatomy is considered, the predicted electric field magnitudes correlate with the recorded values in cortical (r=0...
February 7, 2017: ELife
https://www.readbyqxmd.com/read/28160747/depth-versus-subdural-temporal-electrodes-revisited-impact-on-surgical-outcome-after-resective-surgery-for-epilepsy
#12
A Valentín, N Hernando-Quintana, J Moles-Herbera, D Jimenez-Jimenez, S Mourente, I Malik, R P Selway, G Alarcón
OBJECTIVE: To study retrospectively the impact of electrode modality (subdural or depth electrodes) during presurgical assessment on surgical outcome after temporal lobectomy. METHODS: The study included 17 patients assessed with depth electrodes and 57 with bitemporal subdural strips. RESULTS: MRI showed a larger proportion of bilateral pathology in patients undergoing depth recordings (29.41% versus 3.5%, p=0.00069). Among the operated patients, those undergoing depth electrode recordings showed better outcome at one year after surgery (11/12 versus 22/33; p=0...
December 29, 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28159731/a-prospective-multicenter-single-blind-study-assessing-indices-of-snap-ii-versus-bis-vista-on-surgical-patients-undergoing-general-anesthesia
#13
Sergio D Bergese, Alberto A Uribe, Erika G Puente, R-Jay L Marcus, Randall J Krohn, Steven Docsa, Roy G Soto, Keith A Candiotti
BACKGROUND: Traditionally, anesthesiologists have relied on nonspecific subjective and objective physical signs to assess patients' comfort level and depth of anesthesia. Commercial development of electrical monitors, which use low- and high-frequency electroencephalogram (EEG) signals, have been developed to enhance the assessment of patients' level of consciousness. Multiple studies have shown that monitoring patients' consciousness levels can help in reducing drug consumption, anesthesia-related adverse events, and recovery time...
February 3, 2017: JMIR Research Protocols
https://www.readbyqxmd.com/read/28159538/the-effect-of-systemic-lipoic-acid-on-hearing-preservation-after-cochlear-implantation-via-the-round-window-approach-a-guinea-pig-model
#14
Mun Young Chang, Tae Mok Gwon, Ho Sun Lee, Jun Ho Lee, Seung Ha Oh, Sung June Kim, Min-Hyun Park
The present study aimed to evaluate the effects of systemic lipoic acid on hearing preservation after cochlear implantation. Twelve Dunkin-Hartley guinea pigs were randomly divided into two groups: the control group and the lipoic acid group. Animals in the lipoic acid group received lipoic acid intraperitoneally for 4 weeks. A sterilised silicone electrode-dummy was inserted through the round window to a depth of approximately 5 mm. The hearing level was measured using auditory brainstem responses (ABRs) prior to electrode-dummy insertion, and at 4 days and 1, 2, 3 and 4 weeks after electrode-dummy insertion...
January 31, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28157281/modification-of-silver-single-wall-carbon-nanotube-electrical-contact-interfaces-via-ion-irradiation
#15
Nathanael David Cox, Cory D Cress, Jamie E Rossi, Ivan Puchades, Andrew Merrill, Aaron D Franklin, Brian J Landi
The introduction of defects via ion irradiation ex-situ to modify silver/single-wall carbon nanotube (Ag-SWCNT) electrical contacts and the resulting changes in the electrical properties has been studied. Two test samples were fabricated by depositing 0.1 µm Ag onto SWCNT thin-films with average thicknesses of 10 nm and 60 nm, followed by ion irradiation (150 keV (11)B(+) at 5×10(14) ions/cm(2)). The contact resistance (Rc) between the Ag and SWCNT thin-films was determined using transfer length method (TLM) measurements before and after ion irradiation...
February 3, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28145692/from-carbon-based-nanotubes-to-nanocages-for-advanced-energy-conversion-and-storage
#16
Qiang Wu, Lijun Yang, Xizhang Wang, Zheng Hu
Carbon-based nanomaterials have been the focus of research interests in the past 30 years due to their abundant microstructures and morphologies, excellent properties, and wide potential applications, as landmarked by 0D fullerene, 1D nanotubes, and 2D graphene. With the availability of high specific surface area (SSA), well-balanced pore distribution, high conductivity, and tunable wettability, carbon-based nanomaterials are highly expected as advanced materials for energy conversion and storage to meet the increasing demands for clean and renewable energies...
February 1, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28139318/cochlear-duct-length-one-size-fits-all
#17
J F Thong, D Low, A Tham, C Liew, T Y Tan, H W Yuen
OBJECTIVE: Recent studies demonstrated the utility of high-resolution computed tomography (HRCT) scans in measuring basal cochlear length and cochlear insertion depths. These studies showed significant variations in the anatomy of the cochlea amongst humans. The aim of our study was to investigate for gender and racial variations in the basal turn length of the human cochlea in an Asian population. METHOD: HRCT temporal bone data from year 1997 till 2012 of patients with normally developed cochleae who reported with otologic disease was obtained...
January 21, 2017: American Journal of Otolaryngology
https://www.readbyqxmd.com/read/28131532/high-frequency-spectral-changes-induced-by-single-pulse-electric-stimulation-comparison-between-physiologic-and-pathologic-networks
#18
Mihai Dragos Mălîia, Cristian Donos, Andrei Barborica, Ioana Mindruta, Irina Popa, Mirela Ene, Sándor Beniczky
OBJECTIVE: To investigate functional coupling between brain networks using spectral changes induced by single-pulse electric stimulation (SPES). METHOD: We analyzed 20 patients with focal epilepsy, implanted with depth electrodes. SPES was applied to each pair of adjacent contacts, and responses were recorded from all other contacts. The mean response amplitude value was quantified in three time-periods after stimulation (10-60, 60-255, 255-500ms) for three frequency-ranges (Gamma, Ripples, Fast-Ripples), and compared to baseline...
December 28, 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28113558/the-fabrication-implantation-and-stability-of-intraspinal-microwire-arrays-in-the-spinal-cord-of-cat-and-rat
#19
Jeremy Bamford, R Lebel, Kian Parseyan, Vivian Mushahwar
Intraspinal microstimulation (ISMS) is currently under investigation for its ability to restore function following spinal cord injury and aid in addressing basic investigations of the spinal cord in feline and murine (rat) models. In this report we describe the procedures for fabricating and implanting intraspinal microwires, with special emphasis on the rat model. Furthermore, we report our results on targeting success and long-term stability and functionality of the implants. Early targeting with implants fabricated based on general 'average' dimensions of the spinal cord was approximately 50% successful in reaching the proper targets within the ventral grey matter in cats...
April 28, 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28113472/a-spatially-focused-method-for-high-density-electrode-based-functional-brain-mapping-applications
#20
Chih-Wei Chang, Yue-Loong Hsin, Wentai Liu
Mapping the electric field of the brain with electrodes benefits from its superior temporal resolution but is prone to low spatial resolution property comparing with other modalities such as fMRI, which can directly impact the precision of clinical diagnosis. Simulations show that dense arrays with straightforwardly miniaturized electrodes in terms of size and pitch may not improve the spatial resolution but only strengthen the cross coupling between adjacent channels due to volume conduction. We present a new spatially focused method to improve the electrode spatial selectivity and consequently suppress the neural signal coupling from the sources in the vicinity...
March 7, 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
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