Science.gov

Sample records for integrating electrophysiology contraction

  1. Integrated platform and API for electrophysiological data.

    PubMed

    Sobolev, Andrey; Stoewer, Adrian; Leonhardt, Aljoscha; Rautenberg, Philipp L; Kellner, Christian J; Garbers, Christian; Wachtler, Thomas

    2014-01-01

    Recent advancements in technology and methodology have led to growing amounts of increasingly complex neuroscience data recorded from various species, modalities, and levels of study. The rapid data growth has made efficient data access and flexible, machine-readable data annotation a crucial requisite for neuroscientists. Clear and consistent annotation and organization of data is not only an important ingredient for reproducibility of results and re-use of data, but also essential for collaborative research and data sharing. In particular, efficient data management and interoperability requires a unified approach that integrates data and metadata and provides a common way of accessing this information. In this paper we describe GNData, a data management platform for neurophysiological data. GNData provides a storage system based on a data representation that is suitable to organize data and metadata from any electrophysiological experiment, with a functionality exposed via a common application programming interface (API). Data representation and API structure are compatible with existing approaches for data and metadata representation in neurophysiology. The API implementation is based on the Representational State Transfer (REST) pattern, which enables data access integration in software applications and facilitates the development of tools that communicate with the service. Client libraries that interact with the API provide direct data access from computing environments like Matlab or Python, enabling integration of data management into the scientist's experimental or analysis routines. PMID:24795616

  2. Integrated platform and API for electrophysiological data

    PubMed Central

    Sobolev, Andrey; Stoewer, Adrian; Leonhardt, Aljoscha; Rautenberg, Philipp L.; Kellner, Christian J.; Garbers, Christian; Wachtler, Thomas

    2014-01-01

    Recent advancements in technology and methodology have led to growing amounts of increasingly complex neuroscience data recorded from various species, modalities, and levels of study. The rapid data growth has made efficient data access and flexible, machine-readable data annotation a crucial requisite for neuroscientists. Clear and consistent annotation and organization of data is not only an important ingredient for reproducibility of results and re-use of data, but also essential for collaborative research and data sharing. In particular, efficient data management and interoperability requires a unified approach that integrates data and metadata and provides a common way of accessing this information. In this paper we describe GNData, a data management platform for neurophysiological data. GNData provides a storage system based on a data representation that is suitable to organize data and metadata from any electrophysiological experiment, with a functionality exposed via a common application programming interface (API). Data representation and API structure are compatible with existing approaches for data and metadata representation in neurophysiology. The API implementation is based on the Representational State Transfer (REST) pattern, which enables data access integration in software applications and facilitates the development of tools that communicate with the service. Client libraries that interact with the API provide direct data access from computing environments like Matlab or Python, enabling integration of data management into the scientist's experimental or analysis routines. PMID:24795616

  3. Implementation of Contraction to Electrophysiological Ventricular Myocyte Models, and Their Quantitative Characterization via Post-Extrasystolic Potentiation

    PubMed Central

    Ji, Yanyan Claire; Gray, Richard A.; Fenton, Flavio H.

    2015-01-01

    Heart failure (HF) affects over 5 million Americans and is characterized by impairment of cellular cardiac contractile function resulting in reduced ejection fraction in patients. Electrical stimulation such as cardiac resynchronization therapy (CRT) and cardiac contractility modulation (CCM) have shown some success in treating patients with HF. Computer simulations have the potential to help improve such therapy (e.g. suggest optimal lead placement) as well as provide insight into the underlying mechanisms which could be beneficial. However, these myocyte models require a quantitatively accurate excitation-contraction coupling such that the electrical and contraction predictions are correct. While currently there are close to a hundred models describing the detailed electrophysiology of cardiac cells, the majority of cell models do not include the equations to reproduce contractile force or they have been added ad hoc. Here we present a systematic methodology to couple first generation contraction models into electrophysiological models via intracellular calcium and then compare the resulting model predictions to experimental data. This is done by using a post-extrasystolic pacing protocol, which captures essential dynamics of contractile forces. We found that modeling the dynamic intracellular calcium buffers is necessary in order to reproduce the experimental data. Furthermore, we demonstrate that in models the mechanism of the post-extrasystolic potentiation is highly dependent on the calcium released from the Sarcoplasmic Reticulum. Overall this study provides new insights into both specific and general determinants of cellular contractile force and provides a framework for incorporating contraction into electrophysiological models, both of which will be necessary to develop reliable simulations to optimize electrical therapies for HF. PMID:26317204

  4. Electrophysiological and Mechanical Characteristics in Human Ileal Motility: Recordings of Slow Waves Conductions and Contractions, In vitro.

    PubMed

    Ryoo, Seung-Bum; Oh, Heung-Kwon; Moon, Sang Hui; Choe, Eun Kyung; Yu, Sung A; Park, Sung-Hye; Park, Kyu Joo

    2015-11-01

    Little human tissue data are available for slow waves and migrating motor complexes, which are the main components of small bowel motility. We investigated the electrophysiological and mechanical characteristics of human ileal motility, in vitro. Ileum was obtained from patients undergoing bowel resection. Electrophysiological microelectrode recordings for membrane potential changes and mechanical tension recordings for contraction from smooth muscle strips and ileal segments were performed. Drugs affecting the enteric nervous system were applied to measure the changes in activity. Slow waves were detected with a frequency of 9~10/min. There were no cross-sectional differences in resting membrane potential (RMP), amplitude or frequency between outer and inner circular muscle (CM), suggesting that electrical activities could be effectively transmitted from outer to inner CM. The presence of the interstitial cell of Cajal (ICC) at the linia septa was verified by immunohistochemistry. Contractions of strips and segments occurred at a frequency of 3~4/min and 1~2/min, respectively. The frequency, amplitude and area under the curve were similar between CM and LM. In segments, contractions of CM were associated with LM, but propagation varied with antegrade and retrograde directions. Atropine, N(W)-oxide-L-arginine, and sodium nitroprusside exhibited different effects on RMP and contractions. There were no cross-sectional differences with regard to the characteristics of slow waves in CM. The frequency of contractions in smooth muscle strips and ileal segments was lower than slow waves. The directions of propagation were diverse, indicating both mixing and transport functions of the ileum. PMID:26557020

  5. Capitated contracting of integrated health provider organizations.

    PubMed

    Bazzoli, G J; Dynan, L; Burns, L R

    This paper examines global capitation of integrated health provider organizations that link physicians and hospitals, such as physician-hospital organizations and management service organizations. These organizations have proliferated in recent years, but their contracting activity has not been studied. We develop a conceptual model to understand the capitated contracting bargaining process. Exploratory multivariate analysis suggests that global capitation of these organizations is more common in markets with high health maintenance organization (HMO) market share, greater numbers of HMOs, and fewer physician group practices. Additionally, health provider organizations with more complex case mix, nonprofit status, more affiliated physicians, health system affiliations, and diversity in physician organizational arrangements are more likely to have global capitation. Finally, state regulation of provider contracting with self-insured employers appears to have spillover effects on health plan risk contracting with health providers. PMID:10711318

  6. Functional maturation of human pluripotent stem cell derived cardiomyocytes in vitro--correlation between contraction force and electrophysiology.

    PubMed

    Ribeiro, Marcelo C; Tertoolen, Leon G; Guadix, Juan A; Bellin, Milena; Kosmidis, Georgios; D'Aniello, Cristina; Monshouwer-Kloots, Jantine; Goumans, Marie-Jose; Wang, Yu-Li; Feinberg, Adam W; Mummery, Christine L; Passier, Robert

    2015-05-01

    Cardiomyocytes from human pluripotent stem cells (hPSC-CM) have many potential applications in disease modelling and drug target discovery but their phenotypic similarity to early fetal stages of cardiac development limits their applicability. In this study we compared contraction stresses of hPSC-CM to 2nd trimester human fetal derived cardiomyocytes (hFetal-CM) by imaging displacement of fluorescent beads by single contracting hPSC-CM, aligned by microcontact-printing on polyacrylamide gels. hPSC-CM showed distinctly lower contraction stress than cardiomyocytes isolated from hFetal-CM. To improve maturation of hPSC-CM in vitro we made use of commercial media optimized for cardiomyocyte maturation, which promoted significantly higher contraction stress in hPSC-compared with hFetal-CM. Accordingly, other features of cardiomyocyte maturation were observed, most strikingly increased upstroke velocities and action potential amplitudes, lower resting membrane potentials, improved sarcomeric organization and alterations in cardiac-specific gene expression. Performing contraction force and electrophysiology measurements on individual cardiomyocytes revealed strong correlations between an increase in contraction force and a rise of the upstroke velocity and action potential amplitude and with a decrease in the resting membrane potential. We showed that under standard differentiation conditions hPSC-CM display lower contractile force than primary hFetal-CM and identified conditions under which a commercially available culture medium could induce molecular, morphological and functional maturation of hPSC-CM in vitro. These results are an important contribution for full implementation of hPSC-CM in cardiac disease modelling and drug discovery. PMID:25771005

  7. 48 CFR 3016.170 - Contracts with Lead System Integrators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... performed, in accordance with (FAR) 48 CFR 16.103(a). Contract type and fee structure should be commensurate... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer...

  8. 48 CFR 3016.170 - Contracts with Lead System Integrators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... performed, in accordance with (FAR) 48 CFR 16.103(a). Contract type and fee structure should be commensurate... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer...

  9. 48 CFR 3016.170 - Contracts with Lead System Integrators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... performed, in accordance with (FAR) 48 CFR 16.103(a). Contract type and fee structure should be commensurate... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer...

  10. 48 CFR 3016.170 - Contracts with Lead System Integrators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... performed, in accordance with (FAR) 48 CFR 16.103(a). Contract type and fee structure should be commensurate... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer...

  11. 48 CFR 3016.170 - Contracts with Lead System Integrators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... performed, in accordance with (FAR) 48 CFR 16.103(a). Contract type and fee structure should be commensurate... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Contracts with Lead System... Selecting Contract Types 3016.170 Contracts with Lead System Integrators. The contracting officer...

  12. Contracted auxiliary Gaussian basis integral and derivative evaluation.

    PubMed

    Giese, Timothy J; York, Darrin M

    2008-02-14

    The rapid evaluation of two-center Coulomb and overlap integrals between contracted auxiliary solid harmonic Gaussian functions is examined. Integral expressions are derived from the application of Hobson's theorem and Dunlap's product and differentiation rules of the spherical tensor gradient operator. It is shown that inclusion of the primitive normalization constants greatly simplifies the calculation of contracted functions corresponding to a Gaussian multipole expansion of a diffuse charge density. Derivative expressions are presented and it is shown that chain rules are avoided by expressing the derivatives as a linear combination of auxiliary integrals involving no more than five terms. Calculation of integrals and derivatives requires the contraction of a single vector corresponding to the monopolar result and its scalar derivatives. Implementation of the method is discussed and comparison is made with a Cartesian Gaussian-based method. The current method is superior for the evaluation of both integrals and derivatives using either primitive or contracted functions. PMID:18282025

  13. Integration of massive states as contractions of nonlinear {sigma} models

    SciTech Connect

    Andrianopoli, L.; Ferrara, S.; Lledo, M.A.; Macia, O.

    2005-07-01

    We consider the contraction of some nonlinear {sigma} models which appear in effective supergravity theories. In particular we consider the contractions of maximally symmetric spaces corresponding to N=1 and N=2 theories, as they appear in certain low energy effective supergravity actions with mass deformations. The contraction procedure is shown to describe the integrating out of massive modes in the presence of interactions, as it happens in many supergravity models after spontaneous supersymmetry breaking.

  14. Integrated, automated revenue management for managed care contracts.

    PubMed

    Burckhart, Kent

    2002-04-01

    Faced with increasing managed care penetration and declining net revenue in recent years, healthcare providers increasingly are emphasizing revenue management. To streamline processes and reduce costs in this area, many healthcare providers have implemented or are considering automated contract management systems. When selecting such a system, healthcare financial managers should make certain that the system can interface with both patient-accounting and decision-support systems of the organization. This integration enhances a healthcare provider's financial viability by providing integrated revenue-management capabilities to analyze projected performance of proposed managed care contracts and actual performance of existing contracts. PMID:11963597

  15. Electrophysiological differentiation of phonological and semantic integration in word and sentence contexts

    PubMed Central

    Diaz, Michele T.; Swaab, Tamara Y.

    2006-01-01

    During auditory language comprehension, listeners need to rapidly extract meaning from the continuous speech-stream. It is a matter of debate when and how contextual information constrains the activation of lexical representations in meaningful contexts. Electrophysiological studies of spoken language comprehension have identified an event-related potential (ERP) that was sensitive to phonological properties of speech, which was termed the phonological mismatch negativity (PMN). With the PMN, early lexical processing could potentially be distinguished from processes of semantic integration in spoken language comprehension. However, the sensitivity of the PMN to phonological processing per se has been questioned, and it has additionally been suggested that the “PMN” is not separable from the N400, an ERP that is sensitive to semantic aspects of the input. Here, we investigated whether or not a separable PMN exists and if it reflects purely phonological aspects of the speech input. In the present experiment, ERPs were recorded from healthy young adults (N =24) while they listened to sentences and word lists, in which we manipulated semantic and phonological expectation and congruency of the final word. ERPs sensitive to phonological processing were elicited only when phonological expectancy was violated in lists of words, but not during normal sentential processing. This suggests a differential role of phonological processing in more or less meaningful contexts and indicates a very early influence of the overall context on lexical processing in sentences. PMID:16952338

  16. Integration of Optical Manipulation and Electrophysiological Tools to Modulate and Record Activity in Neural Networks

    NASA Astrophysics Data System (ADS)

    Difato, F.; Schibalsky, L.; Benfenati, F.; Blau, A.

    2011-07-01

    We present an optical system that combines IR (1064 nm) holographic optical tweezers with a sub-nanosecond-pulsed UV (355 nm) laser microdissector for the optical manipulation of single neurons and entire networks both on transparent and non-transparent substrates in vitro. The phase-modulated laser beam can illuminate the sample concurrently or independently from above or below assuring compatibility with different types of microelectrode array and patch-clamp electrophysiology. By combining electrophysiological and optical tools, neural activity in response to localized stimuli or injury can be studied and quantified at sub-cellular, cellular, and network level.

  17. Electrophysiological and psychophysical asymmetries in sensitivity to interaural correlation gaps and implications for binaural integration time.

    PubMed

    Lüddemann, Helge; Kollmeier, Birger; Riedel, Helmut

    2016-02-01

    Brief deviations of interaural correlation (IAC) can provide valuable cues for detection, segregation and localization of acoustic signals. This study investigated the processing of such "binaural gaps" in continuously running noise (100-2000 Hz), in comparison to silent "monaural gaps", by measuring late auditory evoked potentials (LAEPs) and perceptual thresholds with novel, iteratively optimized stimuli. Mean perceptual binaural gap duration thresholds exhibited a major asymmetry: they were substantially shorter for uncorrelated gaps in correlated and anticorrelated reference noise (1.75 ms and 4.1 ms) than for correlated and anticorrelated gaps in uncorrelated reference noise (26.5 ms and 39.0 ms). The thresholds also showed a minor asymmetry: they were shorter in the positive than in the negative IAC range. The mean behavioral threshold for monaural gaps was 5.5 ms. For all five gap types, the amplitude of LAEP components N1 and P2 increased linearly with the logarithm of gap duration. While perceptual and electrophysiological thresholds matched for monaural gaps, LAEP thresholds were about twice as long as perceptual thresholds for uncorrelated gaps, but half as long for correlated and anticorrelated gaps. Nevertheless, LAEP thresholds showed the same asymmetries as perceptual thresholds. For gap durations below 30 ms, LAEPs were dominated by the processing of the leading edge of a gap. For longer gap durations, in contrast, both the leading and the lagging edge of a gap contributed to the evoked response. Formulae for the equivalent rectangular duration (ERD) of the binaural system's temporal window were derived for three common window shapes. The psychophysical ERD was 68 ms for diotic and about 40 ms for anti- and uncorrelated noise. After a nonlinear Z-transform of the stimulus IAC prior to temporal integration, ERDs were about 10 ms for reference correlations of ±1 and 80 ms for uncorrelated reference. Hence, a physiologically motivated

  18. Contracts

    Science.gov Websites

    05, 2016 Contracts For Feb. 04, 2016 Contracts For Feb. 03, 2016 Contracts For Feb. 02, 2016 Contracts For Feb. 01, 2016 Search Contracts Search Recent Oldest Title Title - ...

  19. Contracts

    Science.gov Websites

    2016 Contracts For March 04, 2016 Contracts For March 03, 2016 Contracts For March 02, 2016 Contracts For March 01, 2016 Search Contracts Search Recent Oldest Title Title - ...

  20. Integration of electrophysiological recordings with single-cell RNA-seq data identifies neuronal subtypes.

    PubMed

    Fuzik, János; Zeisel, Amit; Máté, Zoltán; Calvigioni, Daniela; Yanagawa, Yuchio; Szabó, Gábor; Linnarsson, Sten; Harkany, Tibor

    2016-02-01

    Traditionally, neuroscientists have defined the identity of neurons by the cells' location, morphology, connectivity and excitability. However, the direct relationship between these parameters and the molecular phenotypes has remained largely unexplored. Here, we present a method for obtaining full transcriptome data from single neocortical pyramidal cells and interneurons after whole-cell patch-clamp recordings in mouse brain slices. In our approach, termed Patch-seq, a patch-clamp stimulus protocol is followed by the aspiration of the entire somatic compartment into the recording pipette, reverse transcription of RNA including addition of unique molecular identifiers, cDNA amplification, Illumina library preparation and sequencing. We show that Patch-seq reveals a close link between electrophysiological characteristics, responses to acute chemical challenges and RNA expression of neurotransmitter receptors and channels. Moreover, it distinguishes neuronal subpopulations that correspond to both well-established and, to our knowledge, hitherto undescribed neuronal subtypes. Our findings demonstrate the ability of Patch-seq to precisely map neuronal subtypes and predict their network contributions in the brain. PMID:26689544

  1. Mechanisms of Percept-Percept and Image-Percept Integration in Vision: Behavioral and Electrophysiological Evidence

    ERIC Educational Resources Information Center

    Dalvit, Silvia; Eimer, Martin

    2011-01-01

    Previous research has shown that the detection of a visual target can be guided not only by the temporal integration of two percepts, but also by integrating a percept and an image held in working memory. Behavioral and event-related brain potential (ERP) measures were obtained in a target detection task that required temporal integration of 2…

  2. 77 FR 42339 - Improving Contracting Officers' Access to Relevant Integrity Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-18

    ... BUDGET Office of Federal Procurement Policy Improving Contracting Officers' Access to Relevant Integrity... information about contractor business ethics in the Federal Awardee Performance and Integrity Information.../omb/procurement/frn/frn-access-to-relevant-integrity-information-public-comments.pdf . Joseph...

  3. Electrophysiological Evidence for Incremental Lexical-Semantic Integration in Auditory Compound Comprehension

    ERIC Educational Resources Information Center

    Koester, Dirk; Holle, Henning; Gunter, Thomas C.

    2009-01-01

    The present study investigated the time-course of semantic integration in auditory compound word processing. Compounding is a productive mechanism of word formation that is used frequently in many languages. Specifically, we examined whether semantic integration is incremental or is delayed until the head, the last constituent in German, is…

  4. Electrophysiological Endophenotypes for Schizophrenia.

    PubMed

    Owens, Emily M; Bachman, Peter; Glahn, David C; Bearden, Carrie E

    2016-01-01

    Endophenotypes are quantitative, heritable traits that may help to elucidate the pathophysiologic mechanisms underlying complex disease syndromes, such as schizophrenia. They can be assessed at numerous levels of analysis; here, we review electrophysiological endophenotypes that have shown promise in helping us understand schizophrenia from a more mechanistic point of view. For each endophenotype, we describe typical experimental procedures, reliability, heritability, and reported gene and neurobiological associations. We discuss recent findings regarding the genetic architecture of specific electrophysiological endophenotypes, as well as converging evidence from EEG studies implicating disrupted balance of glutamatergic signaling and GABAergic inhibition in the pathophysiology of schizophrenia. We conclude that refining the measurement of electrophysiological endophenotypes, expanding genetic association studies, and integrating data sets are important next steps for understanding the mechanisms that connect identified genetic risk loci for schizophrenia to the disease phenotype. PMID:26954597

  5. Electrophysiological correlates of cross-linguistic semantic integration in hearing signers: N400 and LPC.

    PubMed

    Zachau, Swantje; Korpilahti, Pirjo; Hämäläinen, Jarmo A; Ervast, Leena; Heinänen, Kaisu; Suominen, Kalervo; Lehtihalmes, Matti; Leppänen, Paavo H T

    2014-07-01

    We explored semantic integration mechanisms in native and non-native hearing users of sign language and non-signing controls. Event-related brain potentials (ERPs) were recorded while participants performed a semantic decision task for priming lexeme pairs. Pairs were presented either within speech or across speech and sign language. Target-related ERP responses were subjected to principal component analyses (PCA), and neurocognitive basis of semantic integration processes were assessed by analyzing the N400 and the late positive complex (LPC) components in response to spoken (auditory) and signed (visual) antonymic and unrelated targets. Semantically-related effects triggered across modalities would indicate a similar tight interconnection between the signers׳ two languages like that described for spoken language bilinguals. Remarkable structural similarity of the N400 and LPC components with varying group differences between the spoken and signed targets were found. The LPC was the dominant response. The controls׳ LPC differed from the LPC of the two signing groups. It was reduced to the auditory unrelated targets and was less frontal for all the visual targets. The visual LPC was more broadly distributed in native than non-native signers and was left-lateralized for the unrelated targets in the native hearing signers only. Semantic priming effects were found for the auditory N400 in all groups, but only native hearing signers revealed a clear N400 effect to the visual targets. Surprisingly, the non-native signers revealed no semantically-related processing effect to the visual targets reflected in the N400 or the LPC; instead they appeared to rely more on visual post-lexical analyzing stages than native signers. We conclude that native and non-native signers employed different processing strategies to integrate signed and spoken semantic content. It appeared that the signers׳ semantic processing system was affected by group-specific factors like language

  6. "Reality" of near-death-experience memories: evidence from a psychodynamic and electrophysiological integrated study.

    PubMed

    Palmieri, Arianna; Calvo, Vincenzo; Kleinbub, Johann R; Meconi, Federica; Marangoni, Matteo; Barilaro, Paolo; Broggio, Alice; Sambin, Marco; Sessa, Paola

    2014-01-01

    The nature of near-death-experiences (NDEs) is largely unknown but recent evidence suggests the intriguing possibility that NDEs may refer to actually "perceived," and stored, experiences (although not necessarily in relation to the external physical world). We adopted an integrated approach involving a hypnosis-based clinical protocol to improve recall and decrease memory inaccuracy together with electroencephalography (EEG) recording in order to investigate the characteristics of NDE memories and their neural markers compared to memories of both real and imagined events. We included 10 participants with NDEs, defined by the Greyson NDE scale, and 10 control subjects without NDE. Memories were assessed using the Memory Characteristics Questionnaire. Our hypnosis-based protocol increased the amount of details in the recall of all kind of memories considered (NDE, real, and imagined events). Findings showed that NDE memories were similar to real memories in terms of detail richness, self-referential, and emotional information. Moreover, NDE memories were significantly different from memories of imagined events. The pattern of EEG results indicated that real memory recall was positively associated with two memory-related frequency bands, i.e., high alpha and gamma. NDE memories were linked with theta band, a well-known marker of episodic memory. The recall of NDE memories was also related to delta band, which indexes processes such as the recollection of the past, as well as trance states, hallucinations, and other related portals to transpersonal experience. It is notable that the EEG pattern of correlations for NDE memory recall differed from the pattern for memories of imagined events. In conclusion, our findings suggest that, at a phenomenological level, NDE memories cannot be considered equivalent to imagined memories, and at a neural level, NDE memories are stored as episodic memories of events experienced in a peculiar state of consciousness. PMID:24994974

  7. An efficient algorithm for electron repulsion integrals over contracted Gaussian-type functions

    NASA Astrophysics Data System (ADS)

    Ten-no, Seiichiro

    1993-08-01

    An efficient new algorithm for two-electron repulsion integrals (ERIs) over contracted Cartesian Gaussian-type functions has been proposed, making use of the contracted recurrence relation (CRR) derived here. The CRR, which is obtained by extending the auxiliary function-based methodologies, enables us to remove all the transformations to increment angular momentum of ERIs from the contraction loops. The new scheme turns out to be very suitable for contracted ERIs. Explicit flop (floating point operation) counts indicate about 60% reduction of computational work in the innermost contraction loop for (pp|pp) and (sp) 4 ERI classes, compared to the recent scheme of Gill, Head-Gordon and Pople.

  8. Contractions

    MedlinePlus

    ... feel tightening of your uterus muscles at irregular intervals or a squeezing sensation in your lower abdomen ... beginning of childbirth. These contractions come at regular intervals, usually move from the back to the lower ...

  9. Promised and Delivered Inducements and Contributions: An Integrated View of Psychological Contract Appraisal

    ERIC Educational Resources Information Center

    Lambert, Lisa Schurer

    2011-01-01

    The reciprocal exchange of employees' work for pay that is central to employment relationships is viewed here through the lens of the psychological contract. A psychological contract involves promised inducements, promised contributions, delivered inducements, and delivered contributions: How an employee cognitively integrates these 4 elements is…

  10. Mapping the cellular electrophysiology of rat sympathetic preganglionic neurones to their roles in cardiorespiratory reflex integration: a whole cell recording study in situ

    PubMed Central

    Stalbovskiy, Alexey O; Briant, Linford J B; Paton, Julian F R; Pickering, Anthony E

    2014-01-01

    Sympathetic preganglionic neurones (SPNs) convey sympathetic activity flowing from the CNS to the periphery to reach the target organs. Although previous in vivo and in vitro cell recording studies have explored their electrophysiological characteristics, it has not been possible to relate these characteristics to their roles in cardiorespiratory reflex integration. We used the working heart–brainstem preparation to make whole cell patch clamp recordings from T3–4 SPNs (n = 98). These SPNs were classified by their distinct responses to activation of the peripheral chemoreflex, diving response and arterial baroreflex, allowing the discrimination of muscle vasoconstrictor-like (MVClike, 39%) from cutaneous vasoconstrictor-like (CVClike, 28%) SPNs. The MVClike SPNs have higher baseline firing frequencies (2.52 ± 0.33 Hz vs. CVClike 1.34 ± 0.17 Hz, P = 0.007). The CVClike have longer after-hyperpolarisations (314 ± 36 ms vs. MVClike 191 ± 13 ms, P < 0.001) and lower input resistance (346 ± 49  MΩ vs. MVClike 496 ± 41 MΩ, P < 0.05). MVClike firing was respiratory-modulated with peak discharge in the late inspiratory/early expiratory phase and this activity was generated by both a tonic and respiratory-modulated barrage of synaptic events that were blocked by intrathecal kynurenate. In contrast, the activity of CVClike SPNs was underpinned by rhythmical membrane potential oscillations suggestive of gap junctional coupling. Thus, we have related the intrinsic electrophysiological properties of two classes of SPNs in situ to their roles in cardiorespiratory reflex integration and have shown that they deploy different cellular mechanisms that are likely to influence how they integrate and shape the distinctive sympathetic outputs. PMID:24665100

  11. Mapping the cellular electrophysiology of rat sympathetic preganglionic neurones to their roles in cardiorespiratory reflex integration: a whole cell recording study in situ.

    PubMed

    Stalbovskiy, Alexey O; Briant, Linford J B; Paton, Julian F R; Pickering, Anthony E

    2014-05-15

    Sympathetic preganglionic neurones (SPNs) convey sympathetic activity flowing from the CNS to the periphery to reach the target organs. Although previous in vivo and in vitro cell recording studies have explored their electrophysiological characteristics, it has not been possible to relate these characteristics to their roles in cardiorespiratory reflex integration. We used the working heart-brainstem preparation to make whole cell patch clamp recordings from T3-4 SPNs (n = 98). These SPNs were classified by their distinct responses to activation of the peripheral chemoreflex, diving response and arterial baroreflex, allowing the discrimination of muscle vasoconstrictor-like (MVC(like), 39%) from cutaneous vasoconstrictor-like (CVC(like), 28%) SPNs. The MVC(like) SPNs have higher baseline firing frequencies (2.52 ± 0.33 Hz vs. CVC(like) 1.34 ± 0.17 Hz, P = 0.007). The CVC(like) have longer after-hyperpolarisations (314 ± 36 ms vs. MVC(like) 191 ± 13 ms, P < 0.001) and lower input resistance (346 ± 49 MΩ vs. MVC(like) 496 ± 41 MΩ, P < 0.05). MVC(like) firing was respiratory-modulated with peak discharge in the late inspiratory/early expiratory phase and this activity was generated by both a tonic and respiratory-modulated barrage of synaptic events that were blocked by intrathecal kynurenate. In contrast, the activity of CVC(like) SPNs was underpinned by rhythmical membrane potential oscillations suggestive of gap junctional coupling. Thus, we have related the intrinsic electrophysiological properties of two classes of SPNs in situ to their roles in cardiorespiratory reflex integration and have shown that they deploy different cellular mechanisms that are likely to influence how they integrate and shape the distinctive sympathetic outputs. PMID:24665100

  12. Challenges of commissioning and contracting for integrated care in the National Health Service (NHS) in England.

    PubMed

    Addicott, Rachael

    2016-01-01

    For many years there has been a separation between purchasing and provision of services in the English National Health Service (NHS). Many studies report that this commissioning function has been weak: purchasers have had little impact or power in negotiations with large acute providers, and have had limited strategic control over the delivery of care. Nevertheless, commissioning has become increasingly embedded in the NHS structure since the arrival of Clinical Commissioning Groups (CCGs) in 2012. Recently, some of these CCGs have focused on how they can contract and commission in different ways to stimulate greater collaboration across providers. This paper examines experiences of commissioning and contracting for integrated care in the English NHS, based on a series of national-level interviews and case studies of five health economies that are implementing novel contracting models. The cases illustrated here demonstrate early experiments to drive innovation through contracting in the NHS that have largely relied on the vision of individual teams or leaders, in combination with external legal, procurement and actuarial support. It is unlikely that this approach will be sustainable or replicable across the country or internationally, despite the best intentions of commissioners. Designing and operating novel contractual approaches will require considerable determination, alongside advanced skills in procurement, contract management and commissioning. The cost of developing new contractual approaches is high, and as the process is difficult and resource-intensive, it is likely that dedicated teams or programs will be required to drive significant improvement. PMID:26328512

  13. Promised and delivered inducements and contributions: an integrated view of psychological contract appraisal.

    PubMed

    Lambert, Lisa Schurer

    2011-07-01

    The reciprocal exchange of employees' work for pay that is central to employment relationships is viewed here through the lens of the psychological contract. A psychological contract involves promised inducements, promised contributions, delivered inducements, and delivered contributions: How an employee cognitively integrates these 4 elements is a central question in psychological contract theory. Three alternative approaches for integrating the 4 elements were drawn from discrepancy theory, from equity theory, and from need theories of satisfaction, respectively. Experimental findings disconfirmed the discrepancy and equity approaches. Findings were consistent with the premise of the needs model, which is that appraisal is driven by how psychological contract elements facilitate or hinder an employee's effort to fulfill personal needs. Results showed that promised and delivered pay and work contribute uniquely to appraisal but that they vary in their influence on appraisal. These findings were consistent with the needs model principle that elements proximal to need satisfaction matter more than distal elements. That is, what is delivered (for pay and for work) matters more than what is promised, and pay matters more than work. PMID:21142346

  14. What hemodynamic (fNIRS), electrophysiological (EEG) and autonomic integrated measures can tell us about emotional processing.

    PubMed

    Balconi, Michela; Grippa, Elisabetta; Vanutelli, Maria Elide

    2015-04-01

    Due to its fast temporal evolution and its representation and integration among complex and widespread neural networks, the emotion perception process should preferably be examined by means of multimethodological approach. Indeed the indubitable vantage of acquiring both the autonomic (arousal-related) and the central (cortical-related) activities stands in the possibility to better elucidate the reciprocal interplay of the two compartments. In the present study EEG (frequency band analysis), systemic SCR and heart rate (HR) were all recorded simultaneously with hemodynamic (NIRS, Near-Infrared Spectroscopy) measurements as potential biological markers of emotions, related to both central and peripheral systems. These multiple measures were then related to the self-report correlates, that is the subjective appraisal in term of valence (positive vs. negative) and arousal (high vs. low) by using SAM rating. Twenty subjects were submitted to emotional cues processing (IAPS) when fNIRS, frequency bands (alpha, beta, delta, theta), SCR and HR were recorded. As shown by O2Hb increasing within the right hemisphere, the contribution of prefrontal cortex was elucidated, by pointing out a relevant lateralization effect (more right-PFC activity) induced by the specific valence (negative) of the emotional patterns. Secondly, EEG activity (mainly low-frequency theta and delta bands) was intrinsically associated with the cortical hemodynamic responsiveness to the negative emotional patterns, within the right side. Finally SCR increased mainly in response to negative patterns, and the autonomic behavior was related to explicit (SAM) and cortical (NIRS; EEG) activity. The intrinsic relationships between these three different levels are discussed. PMID:25721430

  15. “Reality” of near-death-experience memories: evidence from a psychodynamic and electrophysiological integrated study

    PubMed Central

    Palmieri, Arianna; Calvo, Vincenzo; Kleinbub, Johann R.; Meconi, Federica; Marangoni, Matteo; Barilaro, Paolo; Broggio, Alice; Sambin, Marco; Sessa, Paola

    2014-01-01

    The nature of near-death-experiences (NDEs) is largely unknown but recent evidence suggests the intriguing possibility that NDEs may refer to actually “perceived,” and stored, experiences (although not necessarily in relation to the external physical world). We adopted an integrated approach involving a hypnosis-based clinical protocol to improve recall and decrease memory inaccuracy together with electroencephalography (EEG) recording in order to investigate the characteristics of NDE memories and their neural markers compared to memories of both real and imagined events. We included 10 participants with NDEs, defined by the Greyson NDE scale, and 10 control subjects without NDE. Memories were assessed using the Memory Characteristics Questionnaire. Our hypnosis-based protocol increased the amount of details in the recall of all kind of memories considered (NDE, real, and imagined events). Findings showed that NDE memories were similar to real memories in terms of detail richness, self-referential, and emotional information. Moreover, NDE memories were significantly different from memories of imagined events. The pattern of EEG results indicated that real memory recall was positively associated with two memory-related frequency bands, i.e., high alpha and gamma. NDE memories were linked with theta band, a well-known marker of episodic memory. The recall of NDE memories was also related to delta band, which indexes processes such as the recollection of the past, as well as trance states, hallucinations, and other related portals to transpersonal experience. It is notable that the EEG pattern of correlations for NDE memory recall differed from the pattern for memories of imagined events. In conclusion, our findings suggest that, at a phenomenological level, NDE memories cannot be considered equivalent to imagined memories, and at a neural level, NDE memories are stored as episodic memories of events experienced in a peculiar state of consciousness. PMID:24994974

  16. Electrophysiological evaluation of psychogenic movement disorders.

    PubMed

    Kamble, Nitish L; Pal, Pramod Kumar

    2016-01-01

    Psychogenic movement disorders (PMD) include a group of neurological symptoms which cannot be explained by any organic syndrome. The diagnosis of PMD is challenging for both neurologist and psychiatrist. Electrophysiological examination is a useful tool to evaluate and support a diagnosis PMD. It includes a set of tests which are chosen appropriate to the clinical setting that provides objective criteria for the diagnosis of PMD. The various tests available include accelerometry, surface electromyography, electroencephalography, jerk locked back averaging and pre-movement potentials, somatosensory evoked potentials, transcranial magnetic stimulation (TMS) etc. Electrophysiologically psychogenic tremors display features of variability, entrainability, coactivation, distractibility and increase in the amplitude and frequency on mass loading. Movement related cortical potentials such as Bereitschaftspotential is seen in psychogenic myoclonus. Presence of triphasic contraction of muscles and absence of co-contraction suggests psychogenic myoclonus. Latency of C-reflex is longer in psychogenic myoclonus as compared to organic myoclonus. The role of TMS to differentiate psychogenic from organic dystonia is still not clear. In conclusion, electrophysiological tests are most useful for tremor, followed by jerks and least for dystonia. In patients with long-standing PMD or those with mixed pathology, electrophysiological tests may not be very useful. PMID:26403429

  17. β-adrenergic effects on cardiac myofilaments and contraction in an integrated rabbit ventricular myocyte model.

    PubMed

    Negroni, Jorge A; Morotti, Stefano; Lascano, Elena C; Gomes, Aldrin V; Grandi, Eleonora; Puglisi, José L; Bers, Donald M

    2015-04-01

    A five-state model of myofilament contraction was integrated into a well-established rabbit ventricular myocyte model of ion channels, Ca(2+) transporters and kinase signaling to analyze the relative contribution of different phosphorylation targets to the overall mechanical response driven by β-adrenergic stimulation (β-AS). β-AS effect on sarcoplasmic reticulum Ca(2+) handling, Ca(2+), K(+) and Cl(-) currents, and Na(+)/K(+)-ATPase properties was included based on experimental data. The inotropic effect on the myofilaments was represented as reduced myofilament Ca(2+) sensitivity (XBCa) and titin stiffness, and increased cross-bridge (XB) cycling rate (XBcy). Assuming independent roles of XBCa and XBcy, the model reproduced experimental β-AS responses on action potentials and Ca(2+) transient amplitude and kinetics. It also replicated the behavior of force-Ca(2+), release-restretch, length-step, stiffness-frequency and force-velocity relationships, and increased force and shortening in isometric and isotonic twitch contractions. The β-AS effect was then switched off from individual targets to analyze their relative impact on contractility. Preventing β-AS effects on L-type Ca(2+) channels or phospholamban limited Ca(2+) transients and contractile responses in parallel, while blocking phospholemman and K(+) channel (IKs) effects enhanced Ca(2+) and inotropy. Removal of β-AS effects from XBCa enhanced contractile force while decreasing peak Ca(2+) (due to greater Ca(2+) buffering), but had less effect on shortening. Conversely, preventing β-AS effects on XBcy preserved Ca(2+) transient effects, but blunted inotropy (both isometric force and especially shortening). Removal of titin effects had little impact on contraction. Finally, exclusion of β-AS from XBCa and XBcy while preserving effects on other targets resulted in preserved peak isometric force response (with slower kinetics) but nearly abolished enhanced shortening. β-AS effects on XBCa and XBcy

  18. β-adrenergic effects on cardiac myofilaments and contraction in an integrated rabbit ventricular myocyte model

    PubMed Central

    Negroni, Jorge A.; Morotti, Stefano; Lascano, Elena C.; Gomes, Aldrin V.; Grandi, Eleonora; Puglisi, José L; Bers, Donald M.

    2015-01-01

    A five-state model of myofilament contraction was integrated into a well-established rabbit ventricular myocyte model of ion channels, Ca2+ transporters and kinase signaling to analyze the relative contribution of different phosphorylation targets to the overall mechanical response driven by β-adrenergic stimulation (β-AS). β-AS effect on sarcoplasmic reticulum Ca2+ handling, Ca2+, K+ and Cl− currents, and Na+/K+-ATPase properties were included based on experimental data. The inotropic effect on the myofilaments was represented as reduced myofilament Ca2+ sensitivity (XBCa) and titin stiffness, and increased cross-bridge (XB) cycling rate (XBcy). Assuming independent roles of XBCa and XBcy, the model reproduced experimental β-AS responses on action potentials and Ca2+ transient amplitude and kinetics. It also replicated the behavior of force-Ca2+, release-restretch, length-step, stiffness-frequency and force-velocity relationships, and increased force and shortening in isometric and isotonic twitch contractions. The β-AS effect was then switched off from individual targets to analyze their relative impact on contractility. Preventing β-AS effects on L-type Ca2+ channels or phospholamban limited Ca2+ transients and contractile responses in parallel, while blocking phospholemman and K+ channel (IKs) effects enhanced Ca2+ and inotropy. Removal of β-AS effects from XBCa enhanced contractile force while decreasing peak Ca2+ (due to greater Ca2+ buffering), but had less effect on shortening. Conversely, preventing β-AS effects on XBcy preserved Ca2+ transient effects, but blunted inotropy (both isometric force and especially shortening). Removal of titin effects had little impact on contraction. Finally, exclusion of β-AS from XBCa and XBcy while preserving effects on other targets resulted in preserved peak isometric force response (with slower kinetics) but nearly abolished enhanced shortening. β-AS effects on XBCa vs. XBcy have greater impact on isometric

  19. Macroscopic contraction of a gel induced by the integrated motion of light-driven molecular motors

    NASA Astrophysics Data System (ADS)

    Li, Quan; Fuks, Gad; Moulin, Emilie; Maaloum, Mounir; Rawiso, Michel; Kulic, Igor; Foy, Justin T.; Giuseppone, Nicolas

    2015-02-01

    Making molecular machines that can be useful in the macroscopic world is a challenging long-term goal of nanoscience. Inspired by the protein machinery found in biological systems, and based on the theoretical understanding of the physics of motion at the nanoscale, organic chemists have developed a number of molecules that can produce work by contraction or rotation when triggered by various external chemical or physical stimuli. In particular, basic molecular switches that commute between at least two thermodynamic minima and more advanced molecular motors that behave as dissipative units working far from equilibrium when fuelled with external energy have been reported. However, despite recent progress, the ultimate challenge of coordinating individual molecular motors in a continuous mechanical process that can have a measurable effect at the macroscale has remained elusive. Here, we show that by integrating light-driven unidirectional molecular rotors as reticulating units in a polymer gel, it is possible to amplify their individual motions to achieve macroscopic contraction of the material. Our system uses the incoming light to operate under far-from-equilibrium conditions, and the work produced by the motor in the photostationary state is used to twist the entangled polymer chains up to the collapse of the gel. Our design could be a starting point to integrate nanomotors in metastable materials to store energy and eventually to convert it.

  20. Advances in Electrophysiological Research.

    PubMed

    Kamarajan, Chella; Porjesz, Bernice

    2015-01-01

    Electrophysiological measures of brain function are effective tools to understand neurocognitive phenomena and sensitive indicators of pathophysiological processes associated with various clinical conditions, including alcoholism. Individuals with alcohol use disorder (AUD) and their high-risk offspring have consistently shown dysfunction in several electrophysiological measures in resting state (i.e., electroencephalogram) and during cognitive tasks (i.e., event-related potentials and event-related oscillations). Researchers have recently developed sophisticated signal-processing techniques to characterize different aspects of brain dynamics, which can aid in identifying the neural mechanisms underlying alcoholism and other related complex disorders.These quantitative measures of brain function also have been successfully used as endophenotypes to identify and help understand genes associated with AUD and related disorders. Translational research also is examining how brain electrophysiological measures potentially can be applied to diagnosis, prevention, and treatment. PMID:26259089

  1. Advances in Electrophysiological Research

    PubMed Central

    Kamarajan, Chella; Porjesz, Bernice

    2015-01-01

    Electrophysiological measures of brain function are effective tools to understand neurocognitive phenomena and sensitive indicators of pathophysiological processes associated with various clinical conditions, including alcoholism. Individuals with alcohol use disorder (AUD) and their high-risk offspring have consistently shown dysfunction in several electrophysiological measures in resting state (i.e., electroencephalogram) and during cognitive tasks (i.e., event-related potentials and event-related oscillations). Researchers have recently developed sophisticated signal-processing techniques to characterize different aspects of brain dynamics, which can aid in identifying the neural mechanisms underlying alcoholism and other related complex disorders. These quantitative measures of brain function also have been successfully used as endophenotypes to identify and help understand genes associated with AUD and related disorders. Translational research also is examining how brain electrophysiological measures potentially can be applied to diagnosis, prevention, and treatment. PMID:26259089

  2. Non-invasive integrative analysis of contraction energetics in intact beating heart.

    PubMed

    Deschodt-Arsac, Véronique; Calmettes, Guillaume; Gouspillou, Gilles; Chapolard, Mathilde; Raffard, Gérard; Rouland, Richard; Jais, Pierre; Haissaguerre, Michel; Dos Santos, Pierre; Diolez, Philippe

    2013-01-01

    The comprehensive study of human pathologies has revealed the complexity of the interactions involved in cardiovascular physiology. The recent validation of system's biology approaches - like our Modular Control and Regulation Analysis (MoCA) - motivates the current interest for new integrative and non-invasive analyses that could be used for medical study of human heart contraction energetics. By considering heart energetics as a supply-demand system, MoCA gives access to integrated organ function and brings out a new type of information, the "elasticities", which describe in situ the regulation of both energy demand and supply by cellular energetic status. These regulations determine the internal control of contraction energetics and may therefore be a key to the understanding of the links between molecular events in pathologies and whole organ function/dysfunction. A wider application to the effects of cardiac drugs in conjunction with the direct study of heart pathologies may be considered in the near future. MoCA can potentially be used not only to detect the origin of the defects associated with the pathology (elasticity analyses), but also to provide a quantitative description of how these defects influence global heart function (regulation analysis) and therefore open new therapeutic perspectives. Several key examples of current applications to intact isolated beating heart are presented in this paper. The future application to human pathologies will require the use of non-invasive NMR techniques for the simultaneous measurement of energy status ((31)P NMR) and heart contractile activity (3D MRI). This article is part of a Directed Issue entitled: Bioenergetic dysfunction, adaptation and therapy. PMID:22789933

  3. Tools for Closure Project and Contract Management: Development of the Rocky Flats Integrated Closure Project Baseline

    SciTech Connect

    Gelles, C. M.; Sheppard, F. R.

    2002-02-26

    This paper details the development of the Rocky Flats Integrated Closure Project Baseline - an innovative project management effort undertaken to ensure proactive management of the Rocky Flats Closure Contract in support of the Department's goal for achieving the safe closure of the Rocky Flats Environmental Technology Site (RFETS) in December 2006. The accelerated closure of RFETS is one of the most prominent projects within the Department of Energy (DOE) Environmental Management program. As the first major former weapons plant to be remediated and closed, it is a first-of-kind effort requiring the resolution of multiple complex technical and institutional challenges. Most significantly, the closure of RFETS is dependent upon the shipment of all special nuclear material and wastes to other DOE sites. The Department is actively working to strengthen project management across programs, and there is increasing external interest in this progress. The development of the Rocky Flats Integrated Closure Project Baseline represents a groundbreaking and cooperative effort to formalize the management of such a complex project across multiple sites and organizations. It is original in both scope and process, however it provides a useful precedent for the other ongoing project management efforts within the Environmental Management program.

  4. Electrophysiological studies in alcoholism

    PubMed Central

    Blackstock, Eileen; Rushworth, Geoffrey; Gath, Dennis

    1972-01-01

    Using a range of electrophysiological techniques, it has been possible to demonstrate impaired function in smaller calibre motor fibres and in distal large cutaneous sensory nerve fibres in both alcoholic patients without neuropathy and in those alcoholics with clinical manifestations of peripheral nerve disease. Evidence of more proximal involvement of Ia sensory fibres was obtained, but in the majority of our patients, large motor fibres functioned normally. The nature of the underlying pathological process is discussed. Images PMID:4338445

  5. Electrophysiology of Axonal Constrictions

    NASA Astrophysics Data System (ADS)

    Johnson, Christopher; Jung, Peter; Brown, Anthony

    2013-03-01

    Axons of myelinated neurons are constricted at the nodes of Ranvier, where they are directly exposed to the extracellular space and where the vast majority of the ion channels are located. These constrictions are generated by local regulation of the kinetics of neurofilaments the most important cytoskeletal elements of the axon. In this paper we discuss how this shape affects the electrophysiological function of the neuron. Specifically, although the nodes are short (about 1 μm) in comparison to the distance between nodes (hundreds of μm) they have a substantial influence on the conduction velocity of neurons. We show through computational modeling that nodal constrictions (all other features such as numbers of ion channels left constant) reduce the required fiber diameter for a given target conduction velocity by up to 50% in comparison to an unconstricted axon. We further show that the predicted optimal fiber morphologies closely match reported fiber morphologies. Supported by The National Science Foundation (IOS 1146789)

  6. ICEPO: the ion channel electrophysiology ontology

    PubMed Central

    Hinard, V.; Britan, A.; Rougier, J.S.; Bairoch, A.; Abriel, H.; Gaudet, P.

    2016-01-01

    Ion channels are transmembrane proteins that selectively allow ions to flow across the plasma membrane and play key roles in diverse biological processes. A multitude of diseases, called channelopathies, such as epilepsies, muscle paralysis, pain syndromes, cardiac arrhythmias or hypoglycemia are due to ion channel mutations. A wide corpus of literature is available on ion channels, covering both their functions and their roles in disease. The research community needs to access this data in a user-friendly, yet systematic manner. However, extraction and integration of this increasing amount of data have been proven to be difficult because of the lack of a standardized vocabulary that describes the properties of ion channels at the molecular level. To address this, we have developed Ion Channel ElectroPhysiology Ontology (ICEPO), an ontology that allows one to annotate the electrophysiological parameters of the voltage-gated class of ion channels. This ontology is based on a three-state model of ion channel gating describing the three conformations/states that an ion channel can adopt: closed, open and inactivated. This ontology supports the capture of voltage-gated ion channel electrophysiological data from the literature in a structured manner and thus enables other applications such as querying and reasoning tools. Here, we present ICEPO (ICEPO ftp site: ftp://ftp.nextprot.org/pub/current_release/controlled_vocabularies/), as well as examples of its use. PMID:27055825

  7. ICEPO: the ion channel electrophysiology ontology.

    PubMed

    Hinard, V; Britan, A; Rougier, J S; Bairoch, A; Abriel, H; Gaudet, P

    2016-01-01

    Ion channels are transmembrane proteins that selectively allow ions to flow across the plasma membrane and play key roles in diverse biological processes. A multitude of diseases, called channelopathies, such as epilepsies, muscle paralysis, pain syndromes, cardiac arrhythmias or hypoglycemia are due to ion channel mutations. A wide corpus of literature is available on ion channels, covering both their functions and their roles in disease. The research community needs to access this data in a user-friendly, yet systematic manner. However, extraction and integration of this increasing amount of data have been proven to be difficult because of the lack of a standardized vocabulary that describes the properties of ion channels at the molecular level. To address this, we have developed Ion Channel ElectroPhysiology Ontology (ICEPO), an ontology that allows one to annotate the electrophysiological parameters of the voltage-gated class of ion channels. This ontology is based on a three-state model of ion channel gating describing the three conformations/states that an ion channel can adopt: closed, open and inactivated. This ontology supports the capture of voltage-gated ion channel electrophysiological data from the literature in a structured manner and thus enables other applications such as querying and reasoning tools. Here, we present ICEPO (ICEPO ftp site:ftp://ftp.nextprot.org/pub/current_release/controlled_vocabularies/), as well as examples of its use. PMID:27055825

  8. Advanced Electrophysiologic Mapping Systems

    PubMed Central

    2006-01-01

    integration of anatomic and electrical potential information that enable better visualization of areas of interest for ablation Advanced nonfluoroscopy mapping/navigation systems appear to be safe; they consistently shortened the fluoroscopy duration and radiation exposure. Evidence suggests that nonfluoroscopy mapping and navigation systems may be used as adjuncts to rather than replacements for fluoroscopy in guiding the ablation of complex arrhythmias. Most studies showed a nonsignificant trend toward lower overall failure rate for advanced mapping-guided ablation compared with fluoroscopy-guided mapping. Pooled analyses of small RCTs and non-RCTs that compared fluoroscopy- with nonfluoroscopy-guided ablation of atrial fibrillation and atrial flutter showed that advanced nonfluoroscopy mapping and navigational systems: Yielded acute success rates of 69% to 100%, not significantly different from fluoroscopy ablation. Had overall failure rates at 3 months to 19 months of 1% to 40% (median 25%). Resulted in a 10% relative reduction in overall failure rate for advanced mapping guided-ablation compared to fluoroscopy guided ablation for the treatment of atrial fibrillation. Yielded added benefit over fluoroscopy in guiding the ablation of complex arrhythmia. The advanced systems were shown to reduce the arrhythmia burden and the need for antiarrhythmic drugs in patients with complex arrhythmia who had failed fluoroscopy-guided ablation Based on predominantly observational studies, circumferential PV ablation guided by a nonfluoroscopy system was shown to do the following: Result in freedom from atrial fibrillation (with or without antiarrhythmic drug) in 75% to 95% of patients (median 79%). This effect was maintained up to 28 months. Result in freedom from atrial fibrillation without antiarrhythmic drugs in 47% to 95% of patients (median 63%). Improve patient survival at 28 months after the procedure as compared with drug therapy. Require special skills; patient outcomes are

  9. Rigorous algorithm for the electron repulsion integral over the generally contracted solid harmonic Gaussian-type orbitals

    NASA Astrophysics Data System (ADS)

    Ishida, Kazuhiro

    2000-11-01

    A rigorous general formula can be derived for the electron repulsion integral (ERI) over the generally contracted (GC) solid harmonic (SH) Gaussian-type orbitals by the use of the "reducing triply mixed solid harmonics" defined in this article. A general algorithm is obtained inductively from the general formula by the use of the "triply mixed solid harmonics" defined in this article. This algorithm is named as ACEb3k3-SH-GC. This ACEb3k3-SH-GC is rigorous and capable of computing the above SH-ERI very fast. Numerical assessment can be performed for (LL|LL) class of SH-ERIs (L=2-5). It is found that the present ACEb3k3-SH-GC is severalfold to a thousandfold faster than the ACEb3k3 algorithm for the usual segment contraction (which is named as ACEb3k3-SH-SC and is the fastest algorithm of all methods in the literature) for the generally contracted (LL|LL) class of SH-ERIs.

  10. Gesundes Kinzigtal Integrated Care: improving population health by a shared health gain approach and a shared savings contract

    PubMed Central

    H., Hildebrandt; C., Hermann; R., Knittel; M., Richter-Reichhelm; A., Siegel; W., Witzenrath

    2010-01-01

    Introduction Integrated care solutions need supportive financial incentives. In this paper, we describe the financial architecture and operative details of the integrated pilot Gesundes Kinzigtal. Description of integrated care case Located in Southwest Germany, Gesundes Kinzigtal is one of the few population-based integrated care approaches in Germany, organising care across all health service sectors and indications. The system serving around half of the population of the region is run by a regional health management company (Gesundes Kinzigtal GmbH) in cooperation with the physicians' network in the region (MQNK), a German health care management company with a background in medical sociology and health economics (OptiMedis AG) and with two statutory health insurers (among them is the biggest health insurer in Southwest Germany: AOK Baden-Württemberg). Discussion and (preliminary) conclusion The shared savings contract between Gesundes Kinzigtal GmbH and the two health insurers, providing financial incentives for managers and health care providers to realize a substantial efficiency gain, could be an appropriate contractual base of Gesundes Kinzigtal's population health gain approach. This approach is based on the assumption that a more effective trans-sector organization of Germany's health care system and increased investments in well-designed preventive programmes will lead to a reduction in morbidity, and in particular to a reduced incidence and prevalence of chronic diseases. This, in turn, is to lead to a comparative reduction in health care cost. Although the comparative cost in the Kinzigtal region has been reduced from the onset of Gesundes Kinzigtal Integrated Care, only future research will have to demonstrate whether—and to what extent—cost reduction may be attributed to a real population health gain. PMID:20689772

  11. Biofeedback in psychomotor training. Electrophysiological basis.

    PubMed

    Bazanova, O M; Mernaya, E M; Shtark, M B

    2009-06-01

    The influences of individual musical practice and the same practice supplemented with biofeedback using electrophysiological markers for optimum music-performing activity were studied in 39 music students. Traditional technical practice produced increases in integral EMG power and decreases in alpha activity in most of the students with initially low maximum alpha activity peak frequencies. Similar practice but combined with individual sessions of alpha-EEG/EMG biofeedback were accompanied by increases in the frequency, bandwidth, and activation responses of EEG alpha rhythms in all subjects, along with decreases in EEG integral power. The efficacy of training with biofeedback and the ability to experience psychomotor learning depended on the initial individual characteristics of EEG alpha activity. PMID:19430974

  12. Children's Electrophysiological Responses to Music.

    ERIC Educational Resources Information Center

    Flohr, John W.; And Others

    This study examined the electrophysiological differences between baseline EEG frequencies and EEG frequencies obtained while listening to music stimuli. The experimental group comprised 22 children, ages 4 to 6 years old, who received special music instruction twice a week for 25 minutes for 7 weeks. The control group received no music…

  13. Resuscitation great. Luigi Galvani and the foundations of electrophysiology.

    PubMed

    Cajavilca, Christian; Varon, Joseph; Sternbach, George L

    2009-02-01

    Luigi Galvani became one of the greatest scientists of the 18th century with his research and the development of his theory on animal electricity. His work was appreciated by many scientists. Nevertheless, it gave rise to one of the most passionate scientific debates in history when Alessandro Volta postulated that Galvani had confused intrinsic animal electricity with small currents produced by metals. This debate would result in the creation of electrophysiology, electromagnetism, electrochemistry and the electrical battery. Galvani responded to each of the postulated theories of Volta giving irrefutable proof of the involvement of electricity in the contraction of muscles. However, his work was subsequently abandoned and silenced for many years but his ideas and theories were finally confirmed by the creation of new instruments and the interest of new scientists who helped position Galvani as the father of electrophysiology. PMID:19059693

  14. Perceived Control and Psychological Contract Breach as Explanations of the Relationships Between Job Insecurity, Job Strain and Coping Reactions: Towards a Theoretical Integration.

    PubMed

    Vander Elst, Tinne; De Cuyper, Nele; Baillien, Elfi; Niesen, Wendy; De Witte, Hans

    2016-04-01

    This study aims to further knowledge on the mechanisms through which job insecurity is related to negative outcomes. Based on appraisal theory, two explanations-perceived control and psychological contract breach-were theoretically integrated in a comprehensive model and simultaneously examined as mediators of the job insecurity-outcome relationship. Different categories of outcomes were considered, namely work-related (i.e. vigour and need for recovery) and general strain (i.e. mental and physical health complaints), as well as psychological (i.e. job satisfaction and organizational commitment) and behavioural coping reactions (i.e. self-rated performance and innovative work behaviour). The hypotheses were tested using data of a heterogeneous sample of 2413 Flemish employees by means of both single and multiple mediator structural equation modelling analyses (bootstrapping method). Particularly, psychological contract breach accounted for the relationship between job insecurity and strain. Both perceived control and psychological contract breach mediated the relationships between job insecurity and psychological coping reactions, although the indirect effects were larger for psychological contract breach. Finally, perceived control was more important than psychological contract breach in mediating the relationships between job insecurity and behavioural coping reactions. This study meets previous calls for a theoretical integration regarding mediators of the job insecurity-outcome relationship. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24916812

  15. Teaching Contracts with Contracts

    ERIC Educational Resources Information Center

    Misner, Robert L.

    1977-01-01

    The teaching of contracts law is an area that lends itself easily to introducing students to realistic factual situations. An exercise is described in which students were assigned to separate "firms" with volunteers from the later law school classes as clients. Each firm was responsible for submitting a signed contract and an accompanying paper.…

  16. Imaging modalities in cardiac electrophysiology.

    PubMed

    Hasan, Reema; Clifford, Sarah M; Ghanbari, Hamid; Schmidt, Martin; Segerson, Nathan M; Daccarett, Marcos

    2010-01-01

    Cardiac imaging, both noninvasive and invasive, has become a crucial part of evaluating patients during the electrophysiology procedure experience. These anatomical data allow electrophysiologists to not only assess who is an appropriate candidate for each procedure, but also to determine the rate of success from these procedures. This article incorporates a review of the various cardiac imaging techniques available today, with a focus on atrial arrhythmias, ventricular arrhythmias and device therapy. PMID:20014991

  17. Historical perspectives of cardiac electrophysiology.

    PubMed

    Lüderitz, Berndt

    2009-01-01

    The diagnosis and treatment of clinical electrophysiology has a long and fascinating history. From earliest times, no clinical symptom impressed the patient (and the physician) more than an irregular heart beat. Although ancient Chinese pulse theory laid the foundation for the study of arrhythmias and clinical electrophysiology in the 5th century BC, the most significant breakthrough in the identification and treatment of cardiac arrhythmias first occurred in this century. In the last decades, our knowledge of electrophysiology and pharmacology has increased exponentially. The enormous clinical significance of cardiac rhythm disturbances has favored these advances. On the one hand, patients live longer and thus are more likely to experience arrhythmias. On the other hand, circulatory problems of the cardiac vessels have increased enormously, and this has been identified as the primary cause of cardiac rhythm disorders. Coronary heart disease has become not just the most significant disease of all, based on the statistics for cause of death. Arrhythmias are the main complication of ischemic heart disease, and they have been directly linked to the frequently arrhythmogenic sudden death syndrome, which is now presumed to be an avoidable "electrical accident" of the heart. A retrospective look--often charming in its own right--may not only make it easier to sort through the copious details of this field and so become oriented in this universe of important and less important facts: it may also provide the observer with a chronological vantage point from which to view the subject. The study of clinical electrophysiology is no dry compendium of facts and figures, but rather a dynamic field of study evolving out of the competition between various ideas, intentions and theories. PMID:19196616

  18. [Biofeedback in psychomotor training. Electrophysiological bases].

    PubMed

    Bazanova, O M; Mernaia, E M; Shtark, M B

    2008-05-01

    Comparison of influence of usual musical practice and the same trainings but using biofeedback on electrophysiological and psychological markers of optimal psychomotor functioning in 39 students-musicians revealed that the obvious musical practice caused psychomotor pressure in most students (with initially low individual alpha peak frequency), whereas similar practice combined with an individualized session of alpha-EEG/EMG biofeedback was accompanied by increase of alpha-activity in all examinees and a decrease (reduction) of integrated EMG that indicated reaching of optimal psychomotor functioning. It appears that the psychomotor learning ability depends on the baseline individual alpha-activity. Individual alpha peak frequency was associated with fluency and efficiency of psychomotor performance, individual alpha band width--with plasticity and creativity, individual amount of alpha suppression in response to opening eyes--with the level of selfactualization. These alpha activity EEG indices correlated with efficiency of the biofeedback training. PMID:18669359

  19. Redox artifacts in electrophysiological recordings

    PubMed Central

    Berman, Jonathan M.

    2013-01-01

    Electrophysiological techniques make use of Ag/AgCl electrodes that are in direct contact with cells or bath. In the bath, electrodes are exposed to numerous experimental conditions and chemical reagents that can modify electrode voltage. We examined voltage offsets created in Ag/AgCl electrodes by exposure to redox reagents used in electrophysiological studies. Voltage offsets were measured in reference to an electrode separated from the solution by an agar bridge. The reducing reagents Tris-2-carboxyethly-phosphine, dithiothreitol (DTT), and glutathione, as well as the oxidizing agent H2O2 used at experimentally relevant concentrations reacted with Ag in the electrodes to produce voltage offsets. Chloride ions and strong acids and bases produced offsets at millimolar concentrations. Electrolytic depletion of the AgCl layer, to replicate voltage clamp and sustained use, resulted in increased sensitivity to flow and DTT. Offsets were sensitive to electrode silver purity and to the amount and method of chloride deposition. For example, exposure to 10 μM DTT produced a voltage offset between 10 and 284 mV depending on the chloride deposition method. Currents generated by these offsets are significant and dependent on membrane conductance and by extension the expression of ion channels and may therefore appear to be biological in origin. These data demonstrate a new source of artifacts in electrophysiological recordings that can affect measurements obtained from a variety of experimental techniques from patch clamp to two-electrode voltage clamp. PMID:23344161

  20. Electrophysiological study of auditory development.

    PubMed

    Lippé, S; Martinez-Montes, E; Arcand, C; Lassonde, M

    2009-12-15

    Cortical auditory evoked potential (CAEP) testing, a non-invasive technique, is widely employed to study auditory brain development. The aim of this study was to investigate the development of the auditory electrophysiological signal without addressing specific abilities such as speech or music discrimination. We were interested in the temporal and spectral domains of conventional auditory evoked potentials. We analyzed cerebral responses to auditory stimulation (broadband noises) in 40 infants and children (1 month to 5 years 6 months) and 10 adults using high-density electrophysiological recording. We hypothesized that the adult auditory response has precursors that can be identified in infant and child responses. Results confirm that complex adult CAEP responses and spectral activity patterns appear after 5 years, showing decreased involvement of lower frequencies and increased involvement of higher frequencies. In addition, time-locked response to stimulus and event-related spectral pertubation across frequencies revealed alpha and beta band contributions to the CAEP of infants and toddlers before mutation to the beta and gamma band activity of the adult response. A detailed analysis of electrophysiological responses to a perceptual stimulation revealed general development patterns and developmental precursors of the adult response. PMID:19665050

  1. Olfaction in dragonflies: electrophysiological evidence.

    PubMed

    Rebora, Manuela; Salerno, Gianandrea; Piersanti, Silvana; Dell'otto, Alessandro; Gaino, Elda

    2012-02-01

    The problem of olfaction in Paleoptera (Odonata, Ephemeroptera) cannot be considered fully elucidated until now. These insects have been traditionally considered anosmic, because their brain lacks glomerular antennal lobes, typically involved in Neoptera odor perception. In order to understand if the presumed coeloconic olfactory receptors described on the antennal flagellum of adult Odonata are really functioning, we performed an electrophysiological investigation with electroantennogram (EAG) and single cell recordings (SCR), using Libellula depressa L. (Odonata, Libellulidae) as a model species. Odors representing different chemical classes such as (Z)-3-hexenyl acetate (acetate ester), (E)-2-hexenal, octanal (aldehydes), (Z)-3-hexen-1-ol (alcohol), propionic acid, butyric acid (carboxylic acids), and 1,4-diaminobutane (amine) were tested. Most of the tested chemicals elicited depolarizing EAG responses in both male and female antennae; SCR show unambiguously for the first time the presence of olfactory neurons in the antennae of L. depressa and strongly support the olfactory function of the coeloconic sensilla located on the antennal flagellum of this species. Electrophysiological activity may not necessarily indicate behavioral activity, and the biological role of olfactory responses in Odonata must be determined in behavioral bioassays. This study represents a starting point for further behavioral, electrophysiological, neuroanatomical and molecular investigation on Odonata olfaction, a research field particularly interesting owing to the basal position of Paleoptera, also for tracing evolutionary trends in insect olfaction. PMID:22154954

  2. Accompanying coordinate expansion and recurrence relation method using a transfer relation scheme for electron repulsion integrals with high angular momenta and long contractions

    SciTech Connect

    Hayami, Masao; Seino, Junji; Nakai, Hiromi

    2015-05-28

    An efficient algorithm for the rapid evaluation of electron repulsion integrals is proposed. The present method, denoted by accompanying coordinate expansion and transferred recurrence relation (ACE-TRR), is constructed using a transfer relation scheme based on the accompanying coordinate expansion and recurrence relation method. Furthermore, the ACE-TRR algorithm is extended for the general-contraction basis sets. Numerical assessments clarify the efficiency of the ACE-TRR method for the systems including heavy elements, whose orbitals have long contractions and high angular momenta, such as f- and g-orbitals.

  3. Impact of pay-for-performance contracts and network registry on diabetes and asthma HEDIS measures in an integrated delivery network.

    PubMed

    Levin-Scherz, Jeffrey; DeVita, Nicole; Timbie, Justin

    2006-02-01

    This article reviews the experience of a large, heterogeneous integrated delivery network that incorporated physician quality metrics into pay-for-performance contracts. The authors present criteria for including measures in pay-for-performance contracts and offer a practical approach to determining withhold return or bonus distribution based on improvement and performance. They demonstrate interventions undertaken to improve performance, including the development of a claims-based registry. Empirical data show that the network performance improved more than the comparable state and national performance during the period of this observational study. The authors conclude that pay-for-performance contracts led to development of medical management programs including a claims-based registry and nonphysician interventions, which helped significantly improve selected HEDIS scores. PMID:16688922

  4. Kingsfield Doesn't Teach My Contracts Class: Using Contracts To Teach Contracts.

    ERIC Educational Resources Information Center

    Warkentine, Edith R.

    2000-01-01

    A law school professor describes her approach to teaching Contracts through the analysis of actual contracts instead of through case briefings. Considered are educational objectives of the Contracts course; the five discrete methods commonly used to teach Contracts; why the author's approach is more successful in integrating theory doctrine, and…

  5. Pediatric & Congenital Electrophysiology Society: building an international paediatric electrophysiology organisation.

    PubMed

    Cohen, Mitchell; Sanatani, Shubhayan; Stephenson, Elizabeth; Skinner, Jon; Drago, Fabrizio; Davis, Andrew; Janousek, Jan; Rosenthal, Eric; Collins, Kathryn K; Triedman, John

    2016-05-01

    The Pediatric and Congenital Electrophysiology Society (PACES) is a non-profit organisation comprised of individuals dedicated to improving the care of children and young adults with cardiac rhythm disturbances. Although PACES is a predominantly North American-centric organisation, international members have been a part of PACES for the last two decades. This year, PACES expanded its North American framework into a broadly expansive international role. On May 12, 2015, paediatric electrophysiology leaders from within the United States of America and Canada met with over 30 international paediatric electrophysiologists from 17 countries and five continents discussing measures to (1) expand PACES' global vision, (2) address ongoing challenges such as limited resource allocation that may be present in developing countries, (3) expand PACES' governance to include international representation, (4) promote joint international sessions at future paediatric EP meetings, and (5) facilitate a global multi-centre research consortium. This meeting marked the inception of a formal international collaborative spirit in PACES. This editorial addresses some solutions to breakdown the continental silos paediatric electrophysiologists have practiced within; however, there remain ongoing limitations, and future discussions will be needed to continue to move the PACES global international vision forward. PMID:27090729

  6. Pediatric & Congenital Electrophysiology Society: building an international paediatric electrophysiology organisation.

    PubMed

    Cohen, Mitchell; Sanatani, Shubhayan; Stephenson, Elizabeth; Skinner, Jon; Drago, Fabrizio; Davis, Andrew; Janousek, Jan; Rosenthal, Eric; Collins, Kathryn K; Triedman, John

    2016-08-01

    The Pediatric and Congenital Electrophysiology Society (PACES) is a non-profit organisation comprised of individuals dedicated to improving the care of children and young adults with cardiac rhythm disturbances. Although PACES is a predominantly North American-centric organisation, international members have been a part of PACES for the last two decades. This year, PACES expanded its North American framework into a broadly expansive international role. On 12 May, 2015, paediatric electrophysiology leaders from within the United States of America and Canada met with over 30 international paediatric electrophysiologists from 17 countries and five continents discussing measures to (1) expand PACES' global vision, (2) address ongoing challenges such as limited resource allocation that may be present in developing countries, (3) expand PACES' governance to include international representation, (4) promote joint international sessions at future paediatric EP meetings, and (5) facilitate a global multi-centre research consortium. This meeting marked the inception of a formal international collaborative spirit in PACES. This editorial addresses some solutions to breakdown the continental silos paediatric electrophysiologists have practiced within; however, there remain ongoing limitations, and future discussions will be needed to continue to move the PACES global international vision forward. PMID:27075202

  7. Electrophysiological evidence for phenomenal consciousness.

    PubMed

    Revonsuo, Antti; Koivisto, Mika

    2010-09-01

    Abstract Recent evidence from event-related brain potentials (ERPs) lends support to two central theses in Lamme's theory. The earliest ERP correlate of visual consciousness appears over posterior visual cortex around 100-200 ms after stimulus onset. Its scalp topography and time window are consistent with recurrent processing in the visual cortex. This electrophysiological correlate of visual consciousness is mostly independent of later ERPs reflecting selective attention and working memory functions. Overall, the ERP evidence supports the view that phenomenal consciousness of a visual stimulus emerges earlier than access consciousness, and that attention and awareness are served by distinct neural processes. PMID:24168341

  8. Personal miniature electrophysiological tape recorder

    NASA Astrophysics Data System (ADS)

    Green, H.

    1981-11-01

    The use of a personal miniature electrophysiological tape recorder to measure the physiological reactions of space flight personnel to space flight stress and weightlessness is described. The Oxford Instruments Medilog recorder, a battery-powered, four-channel cassette tape recorder with 24 hour endurance is carried on the person and will record EKG, EOG, EEG, and timing and event markers. The data will give information about heart rate and morphology changes, and document adaptation to zero gravity on the part of subjects who, unlike highly trained astronauts, are more representative of the normal population than were the subjects of previous space flight studies.

  9. Personal miniature electrophysiological tape recorder

    NASA Technical Reports Server (NTRS)

    Green, H.

    1981-01-01

    The use of a personal miniature electrophysiological tape recorder to measure the physiological reactions of space flight personnel to space flight stress and weightlessness is described. The Oxford Instruments Medilog recorder, a battery-powered, four-channel cassette tape recorder with 24 hour endurance is carried on the person and will record EKG, EOG, EEG, and timing and event markers. The data will give information about heart rate and morphology changes, and document adaptation to zero gravity on the part of subjects who, unlike highly trained astronauts, are more representative of the normal population than were the subjects of previous space flight studies.

  10. [Electrophysiologic study in arrhythmia surgery].

    PubMed

    Nitta, Takashi

    2007-07-01

    The traditional paradigm in surgery for cardiac arrhythmias has been the electrophysiological assessment of the arrhythmia followed by the determination of a specific lesion set for the ablation or a definitive procedure based on the results of the analysis in each patient. The maze procedure was developed as a definitive procedure for atrial fibrillation (AF) and was not guided by electrophysiologic findings in individual patients. The rationale behind the maze procedure is to create a line of conduction block to prevent the propagation of repetitive activations from the pulmonary veins toward the left atrium and to block the reentrant activations occurring on the atrial wall. The cut-and-sew technique is the most reliable method to accomplish conduction block. However, it extends the cardiac arrest and cardiopulmonary times and increases the risk of bleeding. During the past decade, a number of ablation devices have been developed and tested in animals and humans for their ability to create complete conduction block. The use of ablation devices enables less invasive AF surgery. However, the non-transmural or non-contiguous necrosis caused by an incomplete ablation can permit conduction across the ablation line and impair the efficacy of the surgery. Intraoperative verification of conduction block is mandatory to assure the transmurality and contiguity of the lesions created by the ablation devices. PMID:17763669

  11. Premature Contractions

    MedlinePlus

    ... Tools & Resources Stroke More Premature Contractions - PACs and PVCs Updated:Apr 6,2016 Premature contraction = early beat ... chambers of the heart (atria). Premature ventricular contractions (PVCs) start in the lower chambers of the heart ( ...

  12. Electrophysiological correlates of observational learning in children.

    PubMed

    Rodriguez Buritica, Julia M; Eppinger, Ben; Schuck, Nicolas W; Heekeren, Hauke R; Li, Shu-Chen

    2016-09-01

    Observational learning is an important mechanism for cognitive and social development. However, the neurophysiological mechanisms underlying observational learning in children are not well understood. In this study, we used a probabilistic reward-based observational learning paradigm to compare behavioral and electrophysiological markers of individual and observational reinforcement learning in 8- to 10-year-old children. Specifically, we manipulated the amount of observable information as well as children's similarity in age to the observed person (same-aged child vs. adult) to examine the effects of similarity in age on the integration of observed information in children. We show that the feedback-related negativity (FRN) during individual reinforcement learning reflects the valence of outcomes of own actions. Furthermore, we found that the feedback-related negativity during observational reinforcement learning (oFRN) showed a similar distinction between outcome valences of observed actions. This suggests that the oFRN can serve as a measure of observational learning in middle childhood. Moreover, during observational learning children profited from the additional social information and imitated the choices of their own peers more than those of adults, indicating that children have a tendency to conform more with similar others (e.g. their own peers) compared to dissimilar others (adults). Taken together, our results show that children can benefit from integrating observable information and that oFRN may serve as a measure of observational learning in children. PMID:26074422

  13. Electrophysiological and contractile function of cardiomyocytes derived from human embryonic stem cells

    PubMed Central

    Blazeski, Adriana; Zhu, Renjun; Hunter, David W.; Weinberg, Seth H.; Boheler, Kenneth R.; Zambidis, Elias T.; Tung, Leslie

    2013-01-01

    Human embryonic stem cells have emerged as the prototypical source from which cardiomyocytes can be derived for use in drug discovery and cell therapy. However, such applications require that these cardiomyocytes (hESC-CMs) faithfully recapitulate the physiology of adult cells, especially in relation to their electrophysiological and contractile function. We review what is known about the electrophysiology of hESC-CMs in terms of beating rate, action potential characteristics, ionic currents, and cellular coupling as well as their contractility in terms of calcium cycling and contraction. We also discuss the heterogeneity in cellular phenotypes that arises from variability in cardiac differentiation, maturation, and culture conditions, and summarize present strategies that have been implemented to reduce this heterogeneity. Finally, we present original electrophysiological data from optical maps of hESC-CM clusters. PMID:22958937

  14. [Towards optical in vivo electrophysiology].

    PubMed

    Lambot, Laurie; Gall, David

    Optical imaging of voltage indicators is a promising approach for detecting the activity of neuronal circuits with high spatial and temporal resolution. In this context, genetically encoded voltage indicators, combining genetic targeting and optical readout of transmembrane voltage, represent a technological breaktrough that will without doubt have a major impact in neuroscience. However, so far the existing genetically encoded voltage indicators lacked the capabilities to detect individual action potentials and fast spike trains in live animals. Here, we present a novel indicator allowing high-fidelity imaging of individual spikes and dentritic voltage dynamics in vivo. Used in combination with optogenetics, which allows to manipulate neuronal activity, this opens the possibility of an all-optical electrophysiology. PMID:27615186

  15. Electrophysiological investigation of toxic neuropathies.

    PubMed

    Le Quesne, P M

    1982-01-01

    Electrophysiological changes are correlated with pathological processes. Marked slowing of conduction is found in segmental demyelination due to delayed nodal excitation or short lengths of continuous conduction. Secondary demyelination causes slow conduction in hexacarbon neuropathy. Slight reduction in maximal conduction velocity is attributable to selective damage to large fibres in acrylamide neuropathy. Sensory nerve action potential amplitude is a sensitive measure of peripheral nerve function and comparison of abnormalities in different nerve segments may indicate the nature of the underlying pathological change. Other abnormalities may be elucidated by double stimuli; eg repetitive activity due to cholinesterase inhibition only occurs after the first of two closely spaced stimuli. Activity-related excitability changes may be detected by measuring the amplitude of the response to a submaximal stimulus at varying times after a maximal shock and is increased and prolonged by the pyrethroid deltamethrin. PMID:6962658

  16. The Cardiac Electrophysiology Web Lab.

    PubMed

    Cooper, Jonathan; Scharm, Martin; Mirams, Gary R

    2016-01-19

    Computational modeling of cardiac cellular electrophysiology has a long history, and many models are now available for different species, cell types, and experimental preparations. This success brings with it a challenge: how do we assess and compare the underlying hypotheses and emergent behaviors so that we can choose a model as a suitable basis for a new study or to characterize how a particular model behaves in different scenarios? We have created an online resource for the characterization and comparison of electrophysiological cell models in a wide range of experimental scenarios. The details of the mathematical model (quantitative assumptions and hypotheses formulated as ordinary differential equations) are separated from the experimental protocol being simulated. Each model and protocol is then encoded in computer-readable formats. A simulation tool runs virtual experiments on models encoded in CellML, and a website (https://chaste.cs.ox.ac.uk/WebLab) provides a friendly interface, allowing users to store and compare results. The system currently contains a sample of 36 models and 23 protocols, including current-voltage curve generation, action potential properties under steady pacing at different rates, restitution properties, block of particular channels, and hypo-/hyperkalemia. This resource is publicly available, open source, and free, and we invite the community to use it and become involved in future developments. Investigators interested in comparing competing hypotheses using models can make a more informed decision, and those developing new models can upload them for easy evaluation under the existing protocols, and even add their own protocols. PMID:26789753

  17. The digital hearing aid, wearable computing, and electrophysiological response.

    PubMed

    Doyle, T E; Kucerovsky, Z; Greason, W D

    2002-01-01

    Presbycusis is the most common form of hearing loss caused by aging and long-term exposure to sound energy. This type of ailment decreases the ear's ability to perceive high frequencies and localize sound, thus making comprehension more difficult. To compensate for this loss, the choice of a digital hearing aid has become more common. However, most digital hearing aids do little more that their analogue predecessor's by providing a single, fixed hearing response. Such a fixed response is not suitable for all of a user's auditory environments and typically causes a more rapid loss of hearing. Significant advancement in processing power and reduction in size of computing hardware has produced increasingly more powerful, more portable, and more personal computing devices. These advances have spurred research and development of wearable computing devices towards integrating both man and machine. By definition, the digital hearing aid is a wearable computing device. The development of a digital hearing aid with increased onboard processing that is aware of its owner's electrophysiological and auditory environments is an obvious progression. This awareness will give the hearing aid the ability to autonomously modify its own parameters to improve audibility and comprehension. Electrophysiological signals can be classified as naturally occurring or voluntarily controlled. Employing these signals will allow the hearing aid to adapt to its owner's external and internal stimuli. Research and initial experiments into the monitoring and use of electrophysiological response for the control of the digital hearing aid shall be presented. PMID:12085589

  18. Closed-Loop, Open-Source Electrophysiology

    PubMed Central

    Rolston, John D.; Gross, Robert E.; Potter, Steve M.

    2010-01-01

    Multiple extracellular microelectrodes (multi-electrode arrays, or MEAs) effectively record rapidly varying neural signals, and can also be used for electrical stimulation. Multi-electrode recording can serve as artificial output (efferents) from a neural system, while complex spatially and temporally targeted stimulation can serve as artificial input (afferents) to the neuronal network. Multi-unit or local field potential (LFP) recordings can not only be used to control real world artifacts, such as prostheses, computers or robots, but can also trigger or alter subsequent stimulation. Real-time feedback stimulation may serve to modulate or normalize aberrant neural activity, to induce plasticity, or to serve as artificial sensory input. Despite promising closed-loop applications, commercial electrophysiology systems do not yet take advantage of the bidirectional capabilities of multi-electrodes, especially for use in freely moving animals. We addressed this lack of tools for closing the loop with NeuroRighter, an open-source system including recording hardware, stimulation hardware, and control software with a graphical user interface. The integrated system is capable of multi-electrode recording and simultaneous patterned microstimulation (triggered by recordings) with minimal stimulation artifact. The potential applications of closed-loop systems as research tools and clinical treatments are broad; we provide one example where epileptic activity recorded by a multi-electrode probe is used to trigger targeted stimulation, via that probe, to freely moving rodents. PMID:20859448

  19. Closed-loop, open-source electrophysiology.

    PubMed

    Rolston, John D; Gross, Robert E; Potter, Steve M

    2010-01-01

    Multiple extracellular microelectrodes (multi-electrode arrays, or MEAs) effectively record rapidly varying neural signals, and can also be used for electrical stimulation. Multi-electrode recording can serve as artificial output (efferents) from a neural system, while complex spatially and temporally targeted stimulation can serve as artificial input (afferents) to the neuronal network. Multi-unit or local field potential (LFP) recordings can not only be used to control real world artifacts, such as prostheses, computers or robots, but can also trigger or alter subsequent stimulation. Real-time feedback stimulation may serve to modulate or normalize aberrant neural activity, to induce plasticity, or to serve as artificial sensory input. Despite promising closed-loop applications, commercial electrophysiology systems do not yet take advantage of the bidirectional capabilities of multi-electrodes, especially for use in freely moving animals. We addressed this lack of tools for closing the loop with NeuroRighter, an open-source system including recording hardware, stimulation hardware, and control software with a graphical user interface. The integrated system is capable of multi-electrode recording and simultaneous patterned microstimulation (triggered by recordings) with minimal stimulation artifact. The potential applications of closed-loop systems as research tools and clinical treatments are broad; we provide one example where epileptic activity recorded by a multi-electrode probe is used to trigger targeted stimulation, via that probe, to freely moving rodents. PMID:20859448

  20. Microsystems for cell-based electrophysiology

    NASA Astrophysics Data System (ADS)

    Yobas, Levent

    2013-08-01

    Among the electrophysiology techniques, the voltage clamp and its subsequent scaling to smaller mammalian cells, the so-called patch clamp, led to fundamental discoveries in the last century, revealing the ionic mechanisms and the role of single-ion channels in the generation and propagation of action potentials through excitable membranes (e.g. nerves and muscles). Since then, these techniques have gained a reputation as the gold standard of studying cellular ion channels owing to their high accuracy and rich information content via direct measurements under a controlled membrane potential. However, their delicate and skill-laden procedure has put a serious constrain on the throughput and their immediate utilization in the discovery of new cures targeting ion channels until researchers discovered ‘lab-on-a-chip’ as a viable platform for the automation of these techniques into a reliable high-throughput screening functional assay on ion channels. This review examines the innovative ‘lab-on-a-chip’ microtechnologies demonstrated towards this target over a period of slightly more than a decade. The technologies are categorically reviewed according to their considerations for design, fabrication, as well as microfluidic integration from a performance perspective with reference to their ability to secure G Ω seals (gigaseals) on cells, the norm broadly accepted among electrophysiologists for quality recordings that reflect ion-channel activity with high fidelity.

  1. 42 CFR 455.236 - Renewal of a contract.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Renewal of a contract. (a) CMS specifies the initial contract term in the Medicaid integrity audit program contract. CMS may, but is not required to, renew a Medicaid integrity audit program contract without regard... requirements established in the current contract. (b) CMS may renew a Medicaid integrity audit program...

  2. Working memory of emotional stimuli: Electrophysiological characterization.

    PubMed

    Kessel, Dominique; García-Rubio, María J; González, E Kirstin; Tapia, Manuel; López-Martín, Sara; Román, Francisco J; Capilla, Almudena; Martínez, Kenia; Colom, Roberto; Carretié, Luis

    2016-09-01

    Memorizing emotional stimuli in a preferential way seems to be one of the adaptive strategies brought on by evolution for supporting survival. However, there is a lack of electrophysiological evidence on this bias in working memory. The present study analyzed the influence of emotion on the updating component of working memory. Behavioral and electrophysiological indices were measured from a 3-back task using negative, neutral, and positive faces. Electrophysiological data evidenced an emotional influence on the working memory sensitive P3 component, which presented larger amplitudes for negative matching faces compared to neutral ones. This effect originated in the superior parietal cortex, previously reported to be involved in N-back tasks. Additionally, P3 results showed a correlation with reaction times, where higher amplitudes were associated with faster responses for negative matching faces. These findings indicate that electrophysiological measures seem to be very suitable indices of the emotional influence on working memory. PMID:27402441

  3. The electrophysiological development of cardiomyocytes.

    PubMed

    Liu, Jie; Laksman, Zachary; Backx, Peter H

    2016-01-15

    The generation of human cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) has become an important resource for modeling human cardiac disease and for drug screening, and also holds significant potential for cardiac regeneration. Many challenges remain to be overcome however, before innovation in this field can translate into a change in the morbidity and mortality associated with heart disease. Of particular importance for the future application of this technology is an improved understanding of the electrophysiologic characteristics of CMs, so that better protocols can be developed and optimized for generating hPSC-CMs. Many different cell culture protocols are currently utilized to generate CMs from hPSCs and all appear to yield relatively “developmentally” immature CMs with highly heterogeneous electrical properties. These hPSC-CMs are characterized by spontaneous beating at highly variable rates with a broad range of depolarization-repolarization patterns, suggestive of mixed populations containing atrial, ventricular and nodal cells. Many recent studies have attempted to introduce approaches to promote maturation and to create cells with specific functional properties. In this review, we summarize the studies in which the electrical properties of CMs derived from stem cells have been examined. In order to place this information in a useful context, we also review the electrical properties of CMs as they transition from the developing embryo to the adult human heart. The signal pathways involved in the regulation of ion channel expression during development are also briefly considered. PMID:26788696

  4. Electrophysiological characteristics according to activity level of myofascial trigger points.

    PubMed

    Yu, Seong Hun; Kim, Hyun Jin

    2015-09-01

    [Purpose] This study compared the differences in electrophysiological characteristics of normal muscles versus muscles with latent or active myofascial trigger points, and identified the neuromuscular physiological characteristics of muscles with active myofascial trigger points, thereby providing a quantitative evaluation of myofascial pain syndrome and clinical foundational data for its diagnosis. [Subjects] Ninety adults in their 20s participated in this study. Subjects were equally divided into three groups: the active myofascial trigger point group, the latent myofascial trigger point group, and the control group. [Methods] Maximum voluntary isometric contraction (MVIC), endurance, median frequency (MDF), and muscle fatigue index were measured in all subjects. [Results] No significant differences in MVIC or endurance were revealed among the three groups. However, the active trigger point group had significantly different MDF and muscle fatigue index compared with the control group. [Conclusion] Given that muscles with active myofascial trigger points had an increased MDF and suffered muscle fatigue more easily, increased recruitment of motor unit action potential of type II fibers was evident. Therefore, electrophysiological analysis of these myofascial trigger points can be applied to evaluate the effect of physical therapy and provide a quantitative diagnosis of myofascial pain syndrome. PMID:26504306

  5. Electrophysiological characteristics according to activity level of myofascial trigger points

    PubMed Central

    Yu, Seong Hun; Kim, Hyun Jin

    2015-01-01

    [Purpose] This study compared the differences in electrophysiological characteristics of normal muscles versus muscles with latent or active myofascial trigger points, and identified the neuromuscular physiological characteristics of muscles with active myofascial trigger points, thereby providing a quantitative evaluation of myofascial pain syndrome and clinical foundational data for its diagnosis. [Subjects] Ninety adults in their 20s participated in this study. Subjects were equally divided into three groups: the active myofascial trigger point group, the latent myofascial trigger point group, and the control group. [Methods] Maximum voluntary isometric contraction (MVIC), endurance, median frequency (MDF), and muscle fatigue index were measured in all subjects. [Results] No significant differences in MVIC or endurance were revealed among the three groups. However, the active trigger point group had significantly different MDF and muscle fatigue index compared with the control group. [Conclusion] Given that muscles with active myofascial trigger points had an increased MDF and suffered muscle fatigue more easily, increased recruitment of motor unit action potential of type II fibers was evident. Therefore, electrophysiological analysis of these myofascial trigger points can be applied to evaluate the effect of physical therapy and provide a quantitative diagnosis of myofascial pain syndrome. PMID:26504306

  6. Modular regulation analysis of integrative effects of hypoxia on the energetics of contracting skeletal muscle in vivo.

    PubMed

    Beuste, Christophe; Miraux, Sylvain; Deschodt-Arsac, Véronique J; Thiaudiere, Eric; Franconi, Jean-Michel; Diolez, Philippe; Arsac, Laurent M

    2009-05-15

    In the exercising muscle, acute reduction in ambient oxygen impairs muscle contraction because of the effects of hypoxia on mitochondrial ATP supply. The less marked impairment reported after long-term exposure to hypoxia points to changes in the regulation of the energetic system of contraction in HC (hypoxic conditioned) animals. This energetic system is conceptually defined here as two modules: the ATP/PCr (phosphocreatine)-producer and the ATP/PCr-consumer connected by energetic intermediates. Modular control analysis that combines top-down control analysis with non-invasive 31P-NMR spectroscopy was used to describe the effects of hypoxia on each module and their adaptation. Modulations of steady levels of ATP turnover (indirectly assessed as force output) and muscle PCr were obtained in HC rats (6 weeks at 10.5% O2) compared with N (normoxic) rats. Modular control and regulation analyses quantified the elasticity to PCr of each module in N and HC rats as well as the direct effect of acute hypoxia on the ATP/PCr-producer module. Similar elasticities in N and HC rats indicate the absence of response to long-term hypoxia in internal regulations of the ATP supply and demand pathways. The less marked impairment of contraction by acute hypoxia in HC rats (-9+/-6% versus -17+/-14% in N rats, P<0.05) was therefore fully explained by a lower direct effect (HC -31+/-13% versus N -44+/-23%, P<0.05) of acute hypoxia on mitochondrial ATP supply. This points to a positive adaptation to chronic hypoxia. Modular control analysis in vivo may provide powerful tools to find out improved function (alternatively dysfunction) at the system level in conditioned animals. PMID:19228117

  7. Clinical electrophysiology in myasthenia gravis.

    PubMed Central

    Stalberg, E

    1980-01-01

    Effective diagnostic methods are of great importance in order to recognise myasthenic patients among those with muscle fatigability. Intracellular recordings are useful for research work within the field and for detailed description of the motor end-plate's physiology in the individual case. The method is not used for the routine diagnosis of myasthenia gravis. The decrement of the electrical muscle response with nerve stimulation is the most commonly used method. The diagnostic yield is higher in proximal muscles, in warmed muscles, after exercise, and after ischaemia. A significant number of patients may be undiagnosed with this technique. The mechanical response with nerve stimulation shows the same type of decrement but also an abnormal response to long stimulation. The diagnostic value of this is under dispute. Single fibre ENG needs more patient cooperation than do these tests. The diagnostic yield is significantly higher. Some patients considered to have myasthenia gravis do not show any abnormalities with this technique, particularly those with the pure ocular form. Conventional EMG is not useful for the diagnosis of myasthenia, but may be indicated in these patients when concurrent nerve or muscle disease is in question. Tests for eye movement fatique have not proved useful. Stapedius reflex fatigability is demonstrated in about the same proportion of patients as have positive SFEMG findings. The technique is not uncomfortable for the patient and requires minimal cooperation. The general usefulness must be assessed by further routine use. Even with the advent of immunological tests, neurophysiological investigations are indispensable in helping establish the diagnosis of myasthenia gravis. Discrepancies between the results comparing electrophysiological and immunological tests may indicate that myasthenia gravis is a heterogenous entity within which subgroups may be identified. PMID:6249895

  8. Electrophysiological studies of texture recognition mechanisms.

    PubMed

    Kharauzov, A K; Shelepin, Yu E; Pronin, S V; Sel'chenkova, T V; Noskov, Ya A

    2008-03-01

    We report here our electrophysiological and psychophysiological studies of the mechanisms by which the visual system recognizes structured images with different levels of ordering. Visual stimuli consisted of textures, i.e., a set of matrixes consisting of Gabor grids. Matrixes differed in terms of the degree of ordering resulting from changes in the probability that grids with the same orientation would appear. The subject's task was to identify the dominant orientation in the stimulus. The relationship between response accuracy, reaction time, and the main characteristics of evoked potentials on the one hand, and the number of identical grids in the matrix on the other was identified. The proportion of correct responses increased and the reaction time decreased as the degree of ordering of stimuli increased. Visual evoked potentials recorded in the occipital areas showed a relationship between the amplitudes of the N2, P2, and P3 waves, with latent periods of 180, 260, and 400 msec, respectively, and matrix parameters. The amplitudes of the P3 component and the positive component recorded in the frontal leads, with a latent period of 250 msec, increased gradually as the task became simpler. The amplitude of the N2 wave also increased with increases in the number of identically oriented elements in the matrix, though this relationship was S-shaped. The magnitude of the P2 component, conversely, was maximal in response to presentation of those matrixes which were most complex to recognize and gradually decreased as the content of identically oriented grids in the matrix increased. These relationships were compared with the statistical characteristics of the stimuli and assessed in terms of the view that the visual system contains two mechanisms, i.e., local and integral image descriptions. PMID:18264768

  9. Electrophysiology of raccoon cuneocerebellar neurons.

    PubMed

    Haring, J H; Rowinski, M J; Pubols, B H

    1984-01-01

    Electrophysiological experiments were undertaken in order to locate and functionally characterize cells of the raccoon main cuneate nucleus (MCN) that can be activated by electrical stimulation of the cerebellum. A total of 98 such units were studied in pentobarbital sodium-anesthetized, methoxyflurane-anesthetized, or decerebrate preparations. Aside from a greater likelihood of resting discharge in the decerebrate preparations, no appreciable variability in physiological properties of the neurons could be attributed to differences in the type of preparation. Using constant latency of response and ability to be blocked by collision as principal criteria, both antidromically (n = 31) and synaptically (n = 67) activated neurons of the main cuneate nucleus could be identified. A small number of MCN neurons could be activated by both cerebellar and thalamic stimulation, but no unit was antidromically activated from both locations. MCN neurons projecting to the cerebellum are located primarily in the ventral polymorphic cell region of the nucleus at and rostral to the obex, corresponding to the "medial tongue" region of Johnson et al. (1968). In contrast, neurons synaptically activated from the cerebellum are found throughout the dorsoventral extent of the rostral MCN, including the "clusters" region. The majority of antidromically activated units responded to mechanical stimulation of deeper tissues, and most of these were activated by muscle stretch. Only a small portion (13-15%) of either antidromically or synaptically activated units were classed as light touch units with peripheral receptive fields (RFs) restricted to glabrous surfaces of the forepaw. Glabrous skin RFs located on the digital surfaces are smaller than those located on the palm pads. In both cases, RFs are larger than those associated with primary afferent fibers, but toward the low end of the distribution for MCN neurons not activated by cerebellar stimulation. All MCN units activated by cerebellar

  10. Electrophysiological Methods for C. elegans Neurobiology

    PubMed Central

    Goodman, Miriam B.; Lindsay, Theodore H.; Lockery, Shawn R.; Richmond, Janet E.

    2014-01-01

    Patch-clamp electrophysiology is the technique of choice for the biophysical analysis of the function of nerve, muscle, and synapse in C. elegans nematodes. Considerable technical progress has been made in C. elegans electrophysiology in the decade since the initial publication of this technique. Today, most, if not all electrophysiological studies that can be done in larger animal preparations can also be done in C. elegans. This chapter has two main goals. The first is to present to a broad audience the many techniques available for patch-clamp analysis of neurons, muscles, and synapses in C. elegans. The second is to provide a methodological introduction to the techniques for patch-clamping C. elegans neurons and body-wall muscles in vivo, including emerging methods for optogenetic stimulation coupled with post-synaptic recording. We also present samples of the cell-intrinsic and post-synaptic ionic currents that can be measured in C. elegans nerve and muscle. PMID:22226532

  11. The Electrophysiological MEMS Device with Micro Channel Array for Cellular Network Analysis

    NASA Astrophysics Data System (ADS)

    Tonomura, Wataru; Kurashima, Toshiaki; Takayama, Yuzo; Moriguchi, Hiroyuki; Jimbo, Yasuhiko; Konishi, Satoshi

    This paper describes a new type of MCA (Micro Channel Array) for simultaneous multipoint measurement of cellular network. Presented MCA employing the measurement principles of the patch-clamp technique is designed for advanced neural network analysis which has been studied by co-authors using 64ch MEA (Micro Electrode Arrays) system. First of all, sucking and clamping of cells through channels of developed MCA is expected to improve electrophysiological signal detections. Electrophysiological sensing electrodes integrated around individual channels of MCA by using MEMS (Micro Electro Mechanical System) technologies are electrically isolated for simultaneous multipoint measurement. In this study, we tested the developed MCA using the non-cultured rat's cerebral cortical slice and the hippocampal neurons. We could measure the spontaneous action potential of the slice simultaneously at multiple points and culture the neurons on developed MCA. Herein, we describe the experimental results together with the design and fabrication of the electrophysiological MEMS device with MCA for cellular network analysis.

  12. The tarsal taste of honey bees: behavioral and electrophysiological analyses

    PubMed Central

    de Brito Sanchez, Maria Gabriela; Lorenzo, Esther; Su, Songkun; Liu, Fanglin; Zhan, Yi; Giurfa, Martin

    2014-01-01

    Taste plays a crucial role in the life of honey bees as their survival depends on the collection and intake of nectar and pollen, and other natural products. Here we studied the tarsal taste of honey bees through a series of behavioral and electrophysiological analyses. We characterized responsiveness to various sweet, salty and bitter tastants delivered to gustatory sensilla of the fore tarsi. Behavioral experiments showed that stimulation of opposite fore tarsi with sucrose and bitter substances or water yielded different outcomes depending on the stimulation sequence. When sucrose was applied first, thereby eliciting proboscis extension, no bitter substance could induce proboscis retraction, thus suggesting that the primacy of sucrose stimulation induced a central excitatory state. When bitter substances or water were applied first, sucrose stimulation could still elicit proboscis extension but to a lower level, thus suggesting central inhibition based on contradictory gustatory input on opposite tarsi. Electrophysiological experiments showed that receptor cells in the gustatory sensilla of the tarsomeres are highly sensitive to saline solutions at low concentrations. No evidence for receptors responding specifically to sucrose or to bitter substances was found in these sensilla. Receptor cells in the gustatory sensilla of the claws are highly sensitive to sucrose. Although bees do not possess dedicated bitter-taste receptors in the tarsi, indirect bitter detection is possible because bitter tastes inhibit sucrose receptor cells of the claws when mixed with sucrose solution. By combining behavioral and electrophysiological approaches, these results provide the first integrative study on tarsal taste detection in the honey bee. PMID:24550801

  13. Optic Nerve Dysfunction in Obstructive Sleep Apnea: An Electrophysiological Study

    PubMed Central

    Liguori, Claudio; Palmieri, Maria Giuseppina; Pierantozzi, Mariangela; Cesareo, Massimo; Romigi, Andrea; Izzi, Francesca; Marciani, Maria Grazia; Oliva, Corrado; Mercuri, Nicola Biagio; Placidi, Fabio

    2016-01-01

    Study Objectives: The aim of this study was to evaluate the integrity of the visual system in patients affected by obstructive sleep apnea (OSA) by means of electroretinogram (ERG) and visual evoked potential (VEP). Methods: We performed electrophysiological study of the visual system in a population of severe OSA (apnea-hypopnea events/time in bed ≥ 30/h) patients without medical comorbidities compared to a group of healthy controls similar for age, sex, and body mass index. Patients and controls did not have visual impairment or systemic disorders with known influence on the visual system. ERG and VEP were elicited by a reversal pattern generated on a television monitor at low (55') and high (15') spatial frequencies stimulation. Daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS) in both patients and controls. Results: In comparison with healthy controls (n = 27), patients with OSA (n = 27) showed a significant latency delay coupled with a significant amplitude reduction of P100 wave of VEP at all spatial frequencies in both eyes. No significant differences between groups were detected as concerning ERG components. No correlations were found between polygraphic parameters, ESS scores, or VEP and ERG components in OSA patients. Conclusions: This study documented that patients with OSA, without medical comorbidities, present VEP alteration as documented by lower amplitude and longer latency of the P100 component than healthy controls. These altered electrophysiological findings may be the expression of optic nerve dysfunction provoked by hypoxia, acidosis, hypercarbia and airway obstruction, frequently observed in patients with OSA. Hence, we hypothesize that OSA per se may impair optic nerve function. Citation: Liguori C, Palmieri MG, Pierantozzi M, Cesareo M, Romigi A, Izzi F, Marciani MG, Oliva C, Mercuri NB, Placidi F. Optic nerve dysfunction in obstructive sleep apnea: an electrophysiological study. SLEEP 2016;39(1):19–23. PMID

  14. In vitro closed loop optical network electrophysiology: An introduction

    NASA Astrophysics Data System (ADS)

    Hady, A. El; Stühmer, W.

    2013-01-01

    We present a novel experimental paradigm "In vitro closed loop optical network electrophysiology (ivCLONE)". This seminar note gives an overviewof the basics of optical neurostimulation, network electrophysiology and closed loop electrophysiology. Moreover, the notes discuss how combination of aforementioned techniqueswould help us to address network-level phenomenon and how single neuron properties are related to collective network dynamics.

  15. Peripheral Neuropathy – Clinical and Electrophysiological Considerations

    PubMed Central

    Chung, Tae; Prasad, Kalpana; Lloyd, Thomas E.

    2013-01-01

    This article is a primer on the pathophysiology and clinical evaluation of peripheral neuropathy for the radiologist. Magnetic resonance neurography (MRN) has utility in the diagnosis of many focal peripheral nerve lesions. When combined with history, examination, electrophysiology, and laboratory data, future advancements in high-field MRN may play an increasingly important role in the evaluation of patients with peripheral neuropathy. PMID:24210312

  16. Architect's Contract.

    ERIC Educational Resources Information Center

    Ohio State Board of Education, Columbus.

    An actual contract form used for architectural services is presented. Fees, duties, and services are included. Services are listed in the following phases--(1) schematic design, (2) design development, (3) contract document, and (4) construction. Extra services are listed, and owner's responsibility with regard to cost estimates is given.…

  17. Managing Contraction.

    ERIC Educational Resources Information Center

    Taylor, William

    The major thesis of this paper on declining resources and enrollment is that the management of decline, or, as the author calls it, "contraction," is not simply an economic and technical problem; it is basically a conceptual and political one. The author first considers the effects of contraction on schools, buildings, and courses, touching on the…

  18. Performance Contracting.

    ERIC Educational Resources Information Center

    Allen, Tom

    The management team at Minooka (Illinois) School District 201 is actively pursuing school improvement measures by establishing Performance Contracts to increase productivity. The format of the Performance Contract highlights yearly short-term and long-term goals, which are presented in the form of Job Improvement Targets stating the goal itself, a…

  19. Student Contracts.

    ERIC Educational Resources Information Center

    Aldridge, Hal

    1971-01-01

    Discussion of the nature of student-teacher contracts pertaining to academic work to be performed by the student and evaluated by the teacher covers a wide range of related issues in this article. The nature of contracts, evaluation procedures, instructional materials, community attitudes, and the individualization of instruction are commented on…

  20. Contracts. Warranties.

    ERIC Educational Resources Information Center

    Mertz, Gayle

    1988-01-01

    Presents two lesson plans for grades 5-9 which are meant to increase student's legal literacy. The first lesson covers contracts and includes a comic strip which illustrates contract law. The second deals with warranties and why they are important. Included are examples of product warranties. (GEA)

  1. Multiscale Modeling of Gastrointestinal Electrophysiology and Experimental Validation

    PubMed Central

    Du, Peng; O'Grady, Greg; Davidson, John B.; Cheng, Leo K.; Pullan, Andrew J.

    2011-01-01

    Normal gastrointestinal (GI) motility results from the coordinated interplay of multiple cooperating mechanisms, both intrinsic and extrinsic to the GI tract. A fundamental component of this activity is an omnipresent electrical activity termed slow waves, which is generated and propagated by the interstitial cells of Cajal (ICCs). The role of ICC loss and network degradation in GI motility disorders is a significant area of ongoing research. This review examines recent progress in the multiscale modeling framework for effectively integrating a vast range of experimental data in GI electrophysiology, and outlines the prospect of how modeling can provide new insights into GI function in health and disease. The review begins with an overview of the GI tract and its electrophysiology, and then focuses on recent work on modeling GI electrical activity, spanning from cell to body biophysical scales. Mathematical cell models of the ICCs and smooth muscle cell are presented. The continuum framework of monodomain and bidomain models for tissue and organ models are then considered, and the forward techniques used to model the resultant body surface potential and magnetic field are discussed. The review then outlines recent progress in experimental support and validation of modeling, and concludes with a discussion on potential future research directions in this field. PMID:21133835

  2. Extensional vs contractional Cenozoic deformation in Ibiza (Balearic Promontory, Spain): Integration in the West Mediterranean back-arc setting

    NASA Astrophysics Data System (ADS)

    Etheve, Nathalie; Frizon de Lamotte, Dominique; Mohn, Geoffroy; Martos, Raquel; Roca, Eduard; Blanpied, Christian

    2016-07-01

    Based on field work and seismic reflection data, we investigate the Cenozoic tectono-sedimentary evolution offshore and onshore Ibiza allowing the proposal of a new tectonic agenda for the region and its integration in the geodynamic history of the West Mediterranean. The late Oligocene-early Miocene rifting event, which characterizes the Valencia Trough and the Algerian Basin, located north and south of the study area respectively, is also present in Ibiza and particularly well-expressed in the northern part of the island. Among these two rifted basins initiated in the frame of the European Cenozoic Rift System, the Valencia Trough failed rapidly while the Algerian Basin evolved after as a back-arc basin related to the subduction of the Alpine-Maghrebian Tethys. The subsequent middle Miocene compressional deformation was localized by the previous extensional faults, which were either inverted or passively translated depending on their initial orientation. Despite the lateral continuity between the External Betics and the Balearic Promontory, it appears from restored maps that this tectonic event cannot be directly related to the Betic orogen, but results from compressive stresses transmitted through the Algerian Basin. A still active back-arc asthenospheric rise likely explains the stiff behavior of this basin, which has remained poorly deformed up to recent time. During the late Miocene a new extensional episode reworked the southern part of the Balearic Promontory. It is suggested that this extensional deformation developed in a trans-tensional context related to the westward translation of the Alboran Domain and the coeval right-lateral strike-slip movement along the Emile Baudot Escarpment bounding the Algerian Basin to the north.

  3. On the electrophysiology of aesthetic processing.

    PubMed

    Jacobsen, Thomas

    2013-01-01

    One important method that can be applied for gaining an understanding of the underpinning of aesthetics in the brain is that of electrophysiology. Cognitive electrophysiology, in particular, allows the identification of components in a mental processing architecture. The present chapter reviews findings in the neurocognitive psychology of aesthetics, or neuroaesthetics, that have been obtained with the method of event-related brain potentials, as derived from the human electroencephalogram. The cognitive-perceptual bases as well as affective substages of aesthetic processing have been investigated and those are described here. The event-related potential method allows for the identification of mental processing modes in cognitive and aesthetic processing. It also provides an assessment of the mental chronometry of cognitive and affective stages in aesthetic appreciation. As the work described here shows, distinct processes in the brain are engaged in aesthetic judgments. PMID:24041323

  4. Electrophysiological recording from a 'model' cell.

    PubMed

    Zhang, Bing; Stewart, Bryan

    2010-09-01

    The Drosophila larval neuromuscular junction (NMJ) shares many structural and functional similarities to synapses in other animals, including humans. These include the basic feature of synaptic transmission, as well as the molecular mechanisms regulating the synaptic vesicle cycle. Because of its large size, easy accessibility, and the well-characterized genetics, the fly NMJ remains an excellent model system for dissecting the cellular and molecular mechanisms of synaptic transmission. This protocol describes the basics of setting up and conducting electrophysiological experiments using a model cell. For the novice, a model cell provides a way to learn the operation of electrophysiology equipment and software without the anxiety of damaging living cells. This protocol also illustrates passive membrane properties such as the input resistance, capacitance, and time constant. PMID:20810633

  5. Python for Large-Scale Electrophysiology

    PubMed Central

    Spacek, Martin; Blanche, Tim; Swindale, Nicholas

    2008-01-01

    Electrophysiology is increasingly moving towards highly parallel recording techniques which generate large data sets. We record extracellularly in vivo in cat and rat visual cortex with 54-channel silicon polytrodes, under time-locked visual stimulation, from localized neuronal populations within a cortical column. To help deal with the complexity of generating and analysing these data, we used the Python programming language to develop three software projects: one for temporally precise visual stimulus generation (“dimstim”); one for electrophysiological waveform visualization and spike sorting (“spyke”); and one for spike train and stimulus analysis (“neuropy”). All three are open source and available for download (http://swindale.ecc.ubc.ca/code). The requirements and solutions for these projects differed greatly, yet we found Python to be well suited for all three. Here we present our software as a showcase of the extensive capabilities of Python in neuroscience. PMID:19198646

  6. Patch-Clamp Fluorometry: Electrophysiology meets Fluorescence

    PubMed Central

    Kusch, Jana; Zifarelli, Giovanni

    2014-01-01

    Ion channels and transporters are membrane proteins whose functions are driven by conformational changes. Classical biophysical techniques provide insight into either the structure or the function of these proteins, but a full understanding of their behavior requires a correlation of both these aspects in time. Patch-clamp and voltage-clamp fluorometry combine spectroscopic and electrophysiological techniques to simultaneously detect conformational changes and ionic currents across the membrane. Since its introduction, patch-clamp fluorometry has been responsible for invaluable advances in our knowledge of ion channel biophysics. Over the years, the technique has been applied to many different ion channel families to address several biophysical questions with a variety of spectroscopic approaches and electrophysiological configurations. This review illustrates the strength and the flexibility of patch-clamp fluorometry, demonstrating its potential as a tool for future research. PMID:24655500

  7. [Fundamental ophthalmology: the role of electrophysiological studies].

    PubMed

    Zueva, M V

    2014-01-01

    Studying of functional aspects of eye disease pathogenesis by electrophysiological methods is widely demanded in fundamental ophthalmology. Introduction of modern methods of functional assessment into experimental and clinical projects significantly broadens knowledge of normal and pathological functioning of the visual system and is the basis for further development of new strategies of pathogenetic treatment, diagnostics and expert evaluation. Some problems of ophthalmology, including those that concern age-related macular degeneration, glaucoma, diabetic retinopathy, and other diseases, are considered in the context of how much electrophysiology contributes to their solution. The role of functional examinations of the retina in studying pathophysiology of neurodegenerative brain diseases, such as Alzheimer's and Parkinson's, is also discussed. PMID:25715550

  8. Electrophysiological, histochemical, and hormonal adaptation of rat muscle after prolonged hindlimb suspension

    NASA Astrophysics Data System (ADS)

    Kourtidou-Papadeli, Chrysoula; Kyparos, Antonios; Albani, Maria; Frossinis, Athanasios; Papadelis, Christos L.; Bamidis, Panagiotis; Vivas, Ana; Guiba-Tziampiri, Olympia

    2004-05-01

    The perspective of long-duration flights for future exploration, imply more research in the field of human adaptation. Previous studies in rat muscles hindlimb suspension (HLS), indicated muscle atrophy and a change of fibre composition from slow-to-fast twitch types. However, the contractile responses to long-term unloading is still unclear. Fifteen adult Wistar rats were studied in 45 and 70 days of muscle unweighting and soleus (SOL) muscle as well as extensor digitorum longus (EDL) were prepared for electrophysiological recordings (single, twitch, tetanic contraction and fatigue) and histochemical stainings. The loss of muscle mass observed was greater in the soleus muscle. The analysis of electrophysiological properties of both EDL and SOL showed significant main effects of group, of number of unweighting days and fatigue properties. Single contraction for soleus muscle remained unchanged but there was statistically significant difference for tetanic contraction and fatigue. Fatigue index showed a decrease for the control rats, but increase for the HLS rats. According to the histochemical findings there was a shift from oxidative to glycolytic metabolism during HLS. The data suggested that muscles atrophied, but they presented an adaptation pattern, while their endurance in fatigue was decreased.

  9. Past and future aspects of clinical electrophysiology.

    PubMed

    Lüderitz, Berndt

    2008-01-01

    The diagnosis and treatment of clinical electrophysiology has a long and fascinating history. From the earliest time, no clinical symptom impressed the patient (and the physician) more than an irregular heart beat. Although ancient Chinese pulse theory laid the foundation for the study of arrhythmias and clinical electrophysiology in the 5th century BC, the most significant breakthrough in the identification and treatment of cardiac arrhythmias first occurred in this century. In the last decades, our knowledge of electrophysiology and pharmacology has increased exponentially. The enormous clinical significance of cardiac rhythm disturbances has favoured these advances. On the one hand, patients live longer and thus are more likely to experience arrhythmias. On the other hand, circulatory problems of the cardiac vessels have increased enormously, and this has been identified as the primary cause of cardiac rhythm disorders. Coronary heart disease has become not just the most significant disease of all, based on the statistics for cause of death. Arrhythmias are the main complication of ischemic heart disease, and they have been directly linked to the frequent arrhythmogenic sudden death syndrome, which is now presumed to be an avoidable "electrical accident" of the heart. A retrospective look--often charming in its own right--may not only make it easier to sort through the copious details of this field and so become oriented in this universe of important and less important facts; it may also assist the observer in a chronological vantage point of the subject. The study of clinical electrophysiology is no dry compendium of facts and figures, but rather a dynamic field of study evolving out of the competition between various ideas, intentions and theories. PMID:18651426

  10. The P300 as an Electrophysiological Probe of Alcohol Expectancy

    PubMed Central

    Fishman, Inna; Goldman, Mark S.; Donchin, Emanuel

    2008-01-01

    Language-based measures indicate that alcohol expectancies influence alcohol consumption. To relate these measures to brain actions that precede verbal output, the P300 component of the Event-related potentials (ERPs) was used to detect violations of individually held alcohol expectancies. As predicted, P300 amplitude elicited by negative alcohol expectancy stimuli was positively correlated with endorsement of positive/arousing alcohol expectancies on the language-based measure, such that the higher an individual's positive/arousing expectancies, the larger was the P300 elicited by negative alcohol expectancy stimuli. These results demonstrated concordance between language-based measures of alcohol expectancies and electrophysiological probes of expectancy. Although whether these expectancy processes are integral to decision pathways that influence consumption is unknown, these findings suggest that such processing can occur very quickly outside of conscious deliberation. PMID:18729689

  11. Electrophysiological methods for hearing assessment in pinnipeds

    NASA Astrophysics Data System (ADS)

    Reichmuth Kastak, Colleen; Kastak, David; Finneran, James J.; Houser, Dorian S.; Supin, Alexander

    2005-04-01

    Studies of auditory sensitivity in marine mammals generally rely on behavioral psychophysical methodologies. While these studies are the standard for hearing assessment in marine mammals, data are limited to only a few individuals representing a small proportion of species. Accumulating research on dolphin auditory physiology has resulted in the refinement of electrophysiological methods appropriate for odontocete cetaceans and an increase in available audiometric information. Electrophysiological methods have also been used with pinnipeds, but there are significant gaps in our understanding of pinniped auditory physiology that must be addressed before such appoaches can be broadly applied to investigations of pinniped hearing. We are taking a bottom-up approach to developing suitable methods for evoked potential audiometry in pinnipeds, including technology transfer from studies of cetaceans and other mammals, mapping of response amplitude with respect to recording positions on the skull, characterization of responses in relationship to various stimulus types and presentation parameters, and determination of whether useful frequency-specific data can be reliably obtained using electrophysiological methods. This approach is being taken with representative pinniped species including California sea lions (Zalophus californianus), harbor seals (Phoca vitulina), and northern elephant seals (Mirounga angustirostris) using both training and chemical immobilization techniques. [Work supported by NOPP.

  12. Cellular cardiac electrophysiology modeling with Chaste and CellML

    PubMed Central

    Cooper, Jonathan; Spiteri, Raymond J.; Mirams, Gary R.

    2014-01-01

    Chaste is an open-source C++ library for computational biology that has well-developed cardiac electrophysiology tissue simulation support. In this paper, we introduce the features available for performing cardiac electrophysiology action potential simulations using a wide range of models from the Physiome repository. The mathematics of the models are described in CellML, with units for all quantities. The primary idea is that the model is defined in one place (the CellML file), and all model code is auto-generated at compile or run time; it never has to be manually edited. We use ontological annotation to identify model variables describing certain biological quantities (membrane voltage, capacitance, etc.) to allow us to import any relevant CellML models into the Chaste framework in consistent units and to interact with them via consistent interfaces. This approach provides a great deal of flexibility for analysing different models of the same system. Chaste provides a wide choice of numerical methods for solving the ordinary differential equations that describe the models. Fixed-timestep explicit and implicit solvers are provided, as discussed in previous work. Here we introduce the Rush–Larsen and Generalized Rush–Larsen integration techniques, made available via symbolic manipulation of the model equations, which are automatically rearranged into the forms required by these approaches. We have also integrated the CVODE solvers, a ‘gold standard’ for stiff systems, and we have developed support for symbolic computation of the Jacobian matrix, yielding further increases in the performance and accuracy of CVODE. We discuss some of the technical details of this work and compare the performance of the available numerical methods. Finally, we discuss how this is generalized in our functional curation framework, which uses a domain-specific language for defining complex experiments as a basis for comparison of model behavior. PMID:25610400

  13. Cellular cardiac electrophysiology modeling with Chaste and CellML.

    PubMed

    Cooper, Jonathan; Spiteri, Raymond J; Mirams, Gary R

    2014-01-01

    Chaste is an open-source C++ library for computational biology that has well-developed cardiac electrophysiology tissue simulation support. In this paper, we introduce the features available for performing cardiac electrophysiology action potential simulations using a wide range of models from the Physiome repository. The mathematics of the models are described in CellML, with units for all quantities. The primary idea is that the model is defined in one place (the CellML file), and all model code is auto-generated at compile or run time; it never has to be manually edited. We use ontological annotation to identify model variables describing certain biological quantities (membrane voltage, capacitance, etc.) to allow us to import any relevant CellML models into the Chaste framework in consistent units and to interact with them via consistent interfaces. This approach provides a great deal of flexibility for analysing different models of the same system. Chaste provides a wide choice of numerical methods for solving the ordinary differential equations that describe the models. Fixed-timestep explicit and implicit solvers are provided, as discussed in previous work. Here we introduce the Rush-Larsen and Generalized Rush-Larsen integration techniques, made available via symbolic manipulation of the model equations, which are automatically rearranged into the forms required by these approaches. We have also integrated the CVODE solvers, a 'gold standard' for stiff systems, and we have developed support for symbolic computation of the Jacobian matrix, yielding further increases in the performance and accuracy of CVODE. We discuss some of the technical details of this work and compare the performance of the available numerical methods. Finally, we discuss how this is generalized in our functional curation framework, which uses a domain-specific language for defining complex experiments as a basis for comparison of model behavior. PMID:25610400

  14. Computational models of atrial cellular electrophysiology and calcium handling, and their role in atrial fibrillation.

    PubMed

    Heijman, Jordi; Erfanian Abdoust, Pegah; Voigt, Niels; Nattel, Stanley; Dobrev, Dobromir

    2016-02-01

    The complexity of the heart makes an intuitive understanding of the relative contribution of ion channels, transporters and signalling pathways to cardiac electrophysiology challenging. Computational modelling of cardiac cellular electrophysiology has proven useful to integrate experimental findings, extrapolate results obtained in expression systems or animal models to other systems, test quantitatively ideas based on experimental data and provide novel hypotheses that are experimentally testable. While the bulk of computational modelling has traditionally been directed towards ventricular bioelectricity, increasing recognition of the clinical importance of atrial arrhythmias, particularly atrial fibrillation, has led to widespread efforts to apply computational approaches to understanding atrial electrical function. The increasing availability of detailed, atrial-specific experimental data has stimulated the development of novel computational models of atrial-cellular electrophysiology and Ca(2+) handling. To date, more than 300 studies have employed mathematical simulations to enhance our understanding of atrial electrophysiology, arrhythmogenesis and therapeutic responses. Future modelling studies are likely to move beyond current whole-cell models by incorporating new data on subcellular architecture, macromolecular protein complexes, and localized ion-channel regulation by signalling pathways. At the same time, more integrative multicellular models that take into account regional electrophysiological and Ca(2+) handling properties, mechano-electrical feedback and/or autonomic regulation will be needed to investigate the mechanisms governing atrial arrhythmias. A combined experimental and computational approach is expected to provide the more comprehensive understanding of atrial arrhythmogenesis that is required to develop improved diagnostic and therapeutic options. Here, we review this rapidly expanding area, with a particular focus on Ca(2+) handling, and

  15. Portuguese National Registry on Cardiac Electrophysiology, 2013 and 2014.

    PubMed

    Cavaco, Diogo; Morgado, Francisco; Bonhorst, Daniel

    2016-01-01

    The authors present the results of the national registry of electrophysiology of the Portuguese Association for Arrhythmology, Pacing and Electrophysiology (APAPE) for 2013 and 2014. The registry is annual and voluntary, and data are collected retrospectively. Data for electrophysiological studies, ablations and cardioverter-defibrillator implantations for 2013 and 2014 are presented. Developments over the years and their implications are analyzed and discussed. PMID:27396627

  16. Cell-Specific Cardiac Electrophysiology Models

    PubMed Central

    Groenendaal, Willemijn; Ortega, Francis A.; Kherlopian, Armen R.; Zygmunt, Andrew C.; Krogh-Madsen, Trine; Christini, David J.

    2015-01-01

    The traditional cardiac model-building paradigm involves constructing a composite model using data collected from many cells. Equations are derived for each relevant cellular component (e.g., ion channel, exchanger) independently. After the equations for all components are combined to form the composite model, a subset of parameters is tuned, often arbitrarily and by hand, until the model output matches a target objective, such as an action potential. Unfortunately, such models often fail to accurately simulate behavior that is dynamically dissimilar (e.g., arrhythmia) to the simple target objective to which the model was fit. In this study, we develop a new approach in which data are collected via a series of complex electrophysiology protocols from single cardiac myocytes and then used to tune model parameters via a parallel fitting method known as a genetic algorithm (GA). The dynamical complexity of the electrophysiological data, which can only be fit by an automated method such as a GA, leads to more accurately parameterized models that can simulate rich cardiac dynamics. The feasibility of the method is first validated computationally, after which it is used to develop models of isolated guinea pig ventricular myocytes that simulate the electrophysiological dynamics significantly better than does a standard guinea pig model. In addition to improving model fidelity generally, this approach can be used to generate a cell-specific model. By so doing, the approach may be useful in applications ranging from studying the implications of cell-to-cell variability to the prediction of intersubject differences in response to pharmacological treatment. PMID:25928268

  17. Electrophysiology and metabolism of caveolin-3-overexpressing mice.

    PubMed

    Schilling, Jan M; Horikawa, Yousuke T; Zemljic-Harpf, Alice E; Vincent, Kevin P; Tyan, Leonid; Yu, Judith K; McCulloch, Andrew D; Balijepalli, Ravi C; Patel, Hemal H; Roth, David M

    2016-05-01

    Caveolin-3 (Cav-3) plays a critical role in organizing signaling molecules and ion channels involved in cardiac conduction and metabolism. Mutations in Cav-3 are implicated in cardiac conduction abnormalities and myopathies. Additionally, cardiac-specific overexpression of Cav-3 (Cav-3 OE) is protective against ischemic and hypertensive injury, suggesting a potential role for Cav-3 in basal cardiac electrophysiology and metabolism involved in stress adaptation. We hypothesized that overexpression of Cav-3 may alter baseline cardiac conduction and metabolism. We examined: (1) ECG telemetry recordings at baseline and during pharmacological interventions, (2) ion channels involved in cardiac conduction with immunoblotting and computational modeling, and (3) baseline metabolism in Cav-3 OE and transgene-negative littermate control mice. Cav-3 OE mice had decreased heart rates, prolonged PR intervals, and shortened QTc intervals with no difference in activity compared to control mice. Dobutamine or propranolol did not cause significant changes between experimental groups in maximal (dobutamine) or minimal (propranolol) heart rate. Cav-3 OE mice had an overall lower chronotropic response to atropine. The expression of Kv1.4 and Kv4.3 channels, Nav1.5 channels, and connexin 43 were increased in Cav-3 OE mice. A computational model integrating the immunoblotting results indicated shortened action potential duration in Cav-3 OE mice linking the change in channel expression to the observed electrophysiology phenotype. Metabolic profiling showed no gross differences in VO2, VCO2, respiratory exchange ratio, heat generation, and feeding or drinking. In conclusion, Cav-3 OE mice have changes in ECG intervals, heart rates, and cardiac ion channel expression. These findings give novel mechanistic insights into previously reported Cav-3 dependent cardioprotection. PMID:27023865

  18. Multifunctional Catheters Combining Intracardiac Ultrasound Imaging and Electrophysiology Sensing

    PubMed Central

    Stephens, Douglas N.; Cannata, Jonathan; Liu, Ruibin; Zhao, Jian Zhong; Shung, K. Kirk; Nguyen, Hien; Chia, Raymond; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai E.; Mahajan, Aman; Shivkumar, Kalyanam; Kim, Kang; O’Donnell, Matthew; Nikoozadeh, Amin; Oralkan, Omer; Khuri-Yakub, Pierre T.; Sahn, David J.

    2015-01-01

    A family of 3 multifunctional intracardiac imaging and electrophysiology (EP) mapping catheters has been in development to help guide diagnostic and therapeutic intracardiac EP procedures. The catheter tip on the first device includes a 7.5 MHz, 64-element, side-looking phased array for high resolution sector scanning. The second device is a forward-looking catheter with a 24-element 14 MHz phased array. Both of these catheters operate on a commercial imaging system with standard software. Multiple EP mapping sensors were mounted as ring electrodes near the arrays for electrocardiographic synchronization of ultrasound images and used for unique integration with EP mapping technologies. To help establish the catheters’ ability for integration with EP interventional procedures, tests were performed in vivo in a porcine animal model to demonstrate both useful intracardiac echocardiographic (ICE) visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheters also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. The companion paper of this work discusses the catheter design of the side-looking catheter with special attention to acoustic lens design. The third device in development is a 10 MHz forward-looking ring array that is to be mounted at the distal tip of a 9F catheter to permit use of the available catheter lumen for adjunctive therapy tools. PMID:18986948

  19. Electrophysiologic characterization in spinocerebellar ataxia 17.

    PubMed

    Manganelli, F; Perretti, A; Nolano, M; Lanzillo, B; Bruni, A C; De Michele, G; Filla, A; Santoro, L

    2006-03-28

    The authors performed a multimodal electrophysiologic evaluation in nine patients belonging to four SCA17 (spinocerebellar ataxia type 17) families. Peripheral nerve and visual system were not involved. Brainstem auditory evoked potentials were constantly abnormal with central type lesions. Magnetic motor evoked potentials were abnormal only in the lower limbs, suggesting a length-dependent involvement of the pyramidal tract. Somatosensory evoked potentials were abnormal in almost all our patients, and abnormalities were consistent with a somatosensory pathway involvement along the brainstem. PMID:16567717

  20. Contract sanctity

    SciTech Connect

    Seeley, R.S.

    1995-10-01

    Increased competition and the pressure to keep rates low is driving utilities and independent power producers alike to consider more options to keep costs down. While an important strategy for them, the results are creating some conflicts. The April 12, 1995 Federal Energy Regulatory Commission (FERC) decision against New York State Electric & Gas (NYSEG) attempt to breach contracts with two independent power producers, observers say, is one of the most important decisions on contract disputes between independents and utilities. It reveals the complex issues and compelling arguments on both sides. It opens the question of utilities` ability to pay, and the future direction of independent power. The conflicts create a problem for utilities and independents alike.

  1. Protocol for electrophysiological monitoring of carotid endarterectomies

    PubMed Central

    Liu, Hong; Di Giorgio, Anthony M; Williams, Eric S; Evans, William; Russell, Michael J

    2010-01-01

    Near zero stroke rates can be achieved in carotid endarterectomy (CEA) surgery with selective shunting and electrophysiological neuromonitoring. though false negative rates as high as 40% have been reported. We sought to determine if improved training for interpretation of the monitoring signals can advance the efficacy of selective shunting with electrophysiological monitoring across multiple centers, and determine if other factors could contribute to the differences in reports. Processed and raw beta band (12.5-30 Hz) electroencephalogram (EEG) and median and tibial nerve somatosensory evoked potentials (SSEP) were monitored in 668 CEA cases at six surgical centers. A decrease in amplitude of 50% or more in any EEG or SSEP channel was the criteria for shunting or initiating a neuroprotective protocol. A reduction of 50% or greater in the beta band of the EEG or amplitude of the SSEP was observed in 150 cases. No patient showed signs of a cerebral infarct after surgery. Selective shunting based on EEG and SSEP monitoring can reduce CEA intraoperative stroke rate to a near zero level if trained personnel adopted standardized protocols. We also found that the rapid administration of a protective stroke protocol by attending anesthesiologists was an important aspect of this success rate. PMID:23554663

  2. Mechanical and electrophysiological effects of 8-oxoberberine (JKL1073A) on atrial tissue.

    PubMed Central

    Chi, J. F.; Chu, S. H.; Lee, C. S.; Chou, N. K.; Su, M. J.

    1996-01-01

    The effects of 8-oxoberberine (JKL1073A) on contractions and electrophysiological characteristics of atrial tissues were examined. In driven left atria of the rat JKL1073A (10-100 microM) increased twitch tension dose-dependently. In spontaneously beating right atria, JKL1073A increased twitch tension but decreased beating rate slightly. The positive inotropic and the negative chronotropic effect of 30 microM JKL1073A was not affected by prazosin (1 microM), propranolol (1 microM) and 3-isobutyl-1-methyl-xanthine (10 microM) but significantly suppressed by 4-aminopyridine (2 mM 4-AP). Current-clamp study revealed that JKL1073A prolonged rat atrial action potential duration (APD). This prolongation of APD by JKL1073A was decreased by pretreating the cells with 2 mM 4-AP. Voltage-clamp study showed that JKL1073A inhibited the integral of the transient outward current (I(to)) dose-dependently with a KD value of 3.66 +/- 0.93 microM in rat atrial myocytes. The equilibrium dissociation constant (Kd) for JKL1073A bindings to open state I(to) was 0.50 +/- 0.08 microM. The suppression of I(to) by 3 microM JKL1073A was accompanied by shortening of its inactivation time constant from 52.5 +/- 0.9 ms to 16.8 +/- 0.7 ms. V(0.5) for the steady-state inactivation curve of I(to) was shifted from -25.7 +/- 3.3 mV to -34.8 +/- 3.2 mV. In human atrial cells, similar inhibition of I(to) and prolongation of APD by JKL1073A was found. The KD value of JKL1073A for inhibition of the integral of I(to) in human atrial cells is 4.03 +/- 0.02 microM. The Kd for bindings to open state I(to) is 0.5 microM. Currents through K1 channels of rat and human atrial myocytes were not inhibited by JKL1073A at concentrations up to 10 microM. These results indicate that JKL1073A exerts a positive inotropic effect by inhibition of I(to). JKL1073A inhibit I(to) by binding to open state channels or shifting of the steady-state inactivation curve of I(to). PMID:8762071

  3. A Novel Long-term, Multi-Channel and Non-invasive Electrophysiology Platform for Zebrafish.

    PubMed

    Hong, SoonGweon; Lee, Philip; Baraban, Scott C; Lee, Luke P

    2016-01-01

    Zebrafish are a popular vertebrate model for human neurological disorders and drug discovery. Although fecundity, breeding convenience, genetic homology and optical transparency have been key advantages, laborious and invasive procedures are required for electrophysiological studies. Using an electrode-integrated microfluidic system, here we demonstrate a novel multichannel electrophysiology unit to record multiple zebrafish. This platform allows spontaneous alignment of zebrafish and maintains, over days, close contact between head and multiple surface electrodes, enabling non-invasive long-term electroencephalographic recording. First, we demonstrate that electrographic seizure events, induced by pentylenetetrazole, can be reliably distinguished from eye or tail movement artifacts, and quantifiably identified with our unique algorithm. Second, we show long-term monitoring during epileptogenic progression in a scn1lab mutant recapitulating human Dravet syndrome. Third, we provide an example of cross-over pharmacology antiepileptic drug testing. Such promising features of this integrated microfluidic platform will greatly facilitate high-throughput drug screening and electrophysiological characterization of epileptic zebrafish. PMID:27305978

  4. A Novel Long-term, Multi-Channel and Non-invasive Electrophysiology Platform for Zebrafish

    PubMed Central

    Hong, SoonGweon; Lee, Philip; Baraban, Scott C.; Lee, Luke P.

    2016-01-01

    Zebrafish are a popular vertebrate model for human neurological disorders and drug discovery. Although fecundity, breeding convenience, genetic homology and optical transparency have been key advantages, laborious and invasive procedures are required for electrophysiological studies. Using an electrode-integrated microfluidic system, here we demonstrate a novel multichannel electrophysiology unit to record multiple zebrafish. This platform allows spontaneous alignment of zebrafish and maintains, over days, close contact between head and multiple surface electrodes, enabling non-invasive long-term electroencephalographic recording. First, we demonstrate that electrographic seizure events, induced by pentylenetetrazole, can be reliably distinguished from eye or tail movement artifacts, and quantifiably identified with our unique algorithm. Second, we show long-term monitoring during epileptogenic progression in a scn1lab mutant recapitulating human Dravet syndrome. Third, we provide an example of cross-over pharmacology antiepileptic drug testing. Such promising features of this integrated microfluidic platform will greatly facilitate high-throughput drug screening and electrophysiological characterization of epileptic zebrafish. PMID:27305978

  5. Electrophysiological comparison between males and females in HNPP.

    PubMed

    Manganelli, Fiore; Pisciotta, Chiara; Dubbioso, Raffaele; Maruotti, Valerio; Iodice, Rosa; Notturno, Francesca; Ruggiero, Lucia; Vitale, Carmine; Nolano, Maria; Uncini, Antonino; Santoro, Lucio

    2013-08-01

    Some evidences highlighted a higher clinical expression of hereditary neuropathy with liability to pressure palsy (HNPP) in males, and a higher load of traumatic nerve injuries due to different occupational activity has been invoked to explain this observation. It is unknown whether this increased clinical impairment corresponds to a greater electrophysiological involvement. Thus, we compared clinical and electrophysiological features between men and women in a large cohort of HNPP patients. Nerve palsies and electrophysiological abnormalities were more frequent in men, and electrophysiological findings which differentiated males from females did not show any age-related worsening. In conclusion, our findings showed a higher clinical and electrophysiological involvement in males which does not seem related to different cumulative nerve damage over time. We believe that the higher disease expression may increase the chance to detect the disease in males and, thereby, to underestimate the HNPP diagnosis in females. PMID:23207550

  6. Multiplexed, High Density Electrophysiology with Nanofabricated Neural Probes

    PubMed Central

    Du, Jiangang; Blanche, Timothy J.; Harrison, Reid R.; Lester, Henry A.; Masmanidis, Sotiris C.

    2011-01-01

    Extracellular electrode arrays can reveal the neuronal network correlates of behavior with single-cell, single-spike, and sub-millisecond resolution. However, implantable electrodes are inherently invasive, and efforts to scale up the number and density of recording sites must compromise on device size in order to connect the electrodes. Here, we report on silicon-based neural probes employing nanofabricated, high-density electrical leads. Furthermore, we address the challenge of reading out multichannel data with an application-specific integrated circuit (ASIC) performing signal amplification, band-pass filtering, and multiplexing functions. We demonstrate high spatial resolution extracellular measurements with a fully integrated, low noise 64-channel system weighing just 330 mg. The on-chip multiplexers make possible recordings with substantially fewer external wires than the number of input channels. By combining nanofabricated probes with ASICs we have implemented a system for performing large-scale, high-density electrophysiology in small, freely behaving animals that is both minimally invasive and highly scalable. PMID:22022568

  7. Towards predictive modelling of the electrophysiology of the heart

    PubMed Central

    Vigmond, Edward; Vadakkumpadan, Fijoy; Gurev, Viatcheslav; Arevalo, Hermenegild; Deo, Makarand; Plank, Gernot; Trayanova, Natalia

    2010-01-01

    The simulation of cardiac electrical function is an example of a successful integrative multiscale modelling approach that is directly relevant to human disease. Today we stand at the threshold of a new era, in which anatomically detailed, tomographically reconstructed models are being developed that integrate from the ion channel to the electromechanical interactions in the intact heart. Such models hold high promise for interpretation of clinical and physiological measurements, for improving the basic understanding of the mechanisms of dysfunction in disease, such as arrhythmias, myocardial ischaemia and heart failure, and for the development and performance optimization of medical devices. The goal of this article is to present an overview of current state-of-art advances towards predictive computational modelling of the heart as developed recently by the authors of this article. We first outline the methodology for constructing electrophysiological models of the heart. We then provide three examples that demonstrate the use of these models, focusing specifically on the mechanisms for arrhythmogenesis and defibrillation in the heart. These include: (1) uncovering the role of ventricular structure in defibrillation; (2) examining the contribution of Purkinje fibres to the failure of the shock; and (3) using magnetic resonance imaging reconstructed heart models to investigate the re-entrant circuits formed in the presence of an infarct scar. PMID:19270037

  8. Transparent, Flexible, Low Noise Graphene Electrodes for Simultaneous Electrophysiology and Neuroimaging

    PubMed Central

    Kuzum, Duygu; Takano, Hajime; Shim, Euijae; Reed, Jason C; Juul, Halvor; Richardson, Andrew G.; de Vries, Julius; Bink, Hank; Dichter, Marc A.; Lucas, Timothy H.; Coulter, Douglas A.; Cubukcu, Ertugrul; Litt, Brian

    2014-01-01

    Calcium imaging is a versatile experimental approach capable of resolving single neurons with single-cell spatial resolution in the brain. Electrophysiological recordings provide high temporal, but limited spatial resolution, due to the geometrical inaccessibility of the brain. An approach that integrates the advantages of both techniques could provide new insights into functions of neural circuits. Here, we report a transparent, flexible neural electrode technology based on graphene, which enables simultaneous optical imaging and electrophysiological recording. We demonstrate that hippocampal slices can be imaged through transparent graphene electrodes by both confocal and two-photon microscopy without causing any light-induced artifacts in the electrical recordings. Graphene electrodes record high frequency bursting activity and slow synaptic potentials that are hard to resolve by multi-cellular calcium imaging. This transparent electrode technology may pave the way for high spatio-temporal resolution electrooptic mapping of the dynamic neuronal activity. PMID:25327632

  9. Spyke Viewer: a flexible and extensible platform for electrophysiological data analysis

    PubMed Central

    Pröpper, Robert; Obermayer, Klaus

    2013-01-01

    Spyke Viewer is an open source application designed to help researchers analyze data from electrophysiological recordings or neural simulations. It provides a graphical data browser and supports finding and selecting relevant subsets of the data. Users can interact with the selected data using an integrated Python console or plugins. Spyke Viewer includes plugins for several common visualizations and allows users to easily extend the program by writing their own plugins. New plugins are automatically integrated with the graphical interface. Additional plugins can be downloaded and shared on a dedicated website. PMID:24273510

  10. A simple integrated system for electrophysiologic recordings in animals

    PubMed Central

    Slater, Bernard J.; Miller, Neil R.; Bernstein, Steven L.; Flower, Robert W.

    2009-01-01

    This technical note describes a modification to a fundus camera that permits simultaneous recording of pattern electroretinograms (pERGs) and pattern visual evoked potentials (pVEPs). The modification consists of placing an organic light-emitting diode (OLED) in the split-viewer pathway of a fundus camera, in a plane conjugate to the subject’s pupil. In this way, a focused image of the OLED can be delivered to a precisely known location on the retina. The advantage of using an OLED is that it can achieve high luminance while maintaining high contrast, and with minimal degradation over time. This system is particularly useful for animal studies, especially when precise retinal positioning is required. PMID:19137347

  11. Audiovisual integration for speech during mid-childhood: Electrophysiological evidence

    PubMed Central

    Kaganovich, Natalya; Schumaker, Jennifer

    2014-01-01

    Previous studies have demonstrated that the presence of visual speech cues reduces the amplitude and latency of the N1 and P2 event-related potential (ERP) components elicited by speech stimuli. However, the developmental trajectory of this effect is not yet fully mapped. We examined ERP responses to auditory, visual, and audiovisual speech in two groups of school-age children (7–8-year-olds and 10–11-year-olds) and in adults. Audiovisual speech led to the attenuation of the N1 and P2 components in all groups of participants, suggesting that the neural mechanisms underlying these effects are functional by early school years. Additionally, while the reduction in N1 was largest over the right scalp, the P2 attenuation was largest over the left and midline scalp. The difference in the hemispheric distribution of the N1 and P2 attenuation supports the idea that these components index at least somewhat disparate neural processes within the context of audiovisual speech perception. PMID:25463815

  12. Audiovisual integration for speech during mid-childhood: electrophysiological evidence.

    PubMed

    Kaganovich, Natalya; Schumaker, Jennifer

    2014-12-01

    Previous studies have demonstrated that the presence of visual speech cues reduces the amplitude and latency of the N1 and P2 event-related potential (ERP) components elicited by speech stimuli. However, the developmental trajectory of this effect is not yet fully mapped. We examined ERP responses to auditory, visual, and audiovisual speech in two groups of school-age children (7-8-year-olds and 10-11-year-olds) and in adults. Audiovisual speech led to the attenuation of the N1 and P2 components in all groups of participants, suggesting that the neural mechanisms underlying these effects are functional by early school years. Additionally, while the reduction in N1 was largest over the right scalp, the P2 attenuation was largest over the left and midline scalp. The difference in the hemispheric distribution of the N1 and P2 attenuation supports the idea that these components index at least somewhat disparate neural processes within the context of audiovisual speech perception. PMID:25463815

  13. Stimfit: quantifying electrophysiological data with Python

    PubMed Central

    Guzman, Segundo J.; Schlögl, Alois; Schmidt-Hieber, Christoph

    2013-01-01

    Intracellular electrophysiological recordings provide crucial insights into elementary neuronal signals such as action potentials and synaptic currents. Analyzing and interpreting these signals is essential for a quantitative understanding of neuronal information processing, and requires both fast data visualization and ready access to complex analysis routines. To achieve this goal, we have developed Stimfit, a free software package for cellular neurophysiology with a Python scripting interface and a built-in Python shell. The program supports most standard file formats for cellular neurophysiology and other biomedical signals through the Biosig library. To quantify and interpret the activity of single neurons and communication between neurons, the program includes algorithms to characterize the kinetics of presynaptic action potentials and postsynaptic currents, estimate latencies between pre- and postsynaptic events, and detect spontaneously occurring events. We validate and benchmark these algorithms, give estimation errors, and provide sample use cases, showing that Stimfit represents an efficient, accessible and extensible way to accurately analyze and interpret neuronal signals. PMID:24600389

  14. M-sequences in ophthalmic electrophysiology.

    PubMed

    Müller, Philipp L; Meigen, Thomas

    2016-01-01

    The aim of this review is to use the multimedia aspects of a purely digital online publication to explain and illustrate the highly capable technique of m-sequences in multifocal ophthalmic electrophysiology. M-sequences have been successfully applied in clinical routines during the past 20 years. However, the underlying mathematical rationale is often daunting. These mathematical properties of m-sequences allow one not only to separate the responses from different fields but also to analyze adaptational effects and impacts of former events. By explaining the history, the formation, and the different aspects of application, a better comprehension of the technique is intended. With this review we aim to clarify the opportunities of m-sequences in order to motivate scientists to use m-sequences in their future research. PMID:26818968

  15. Electrophysiology of the chemically sympathectomised dog.

    PubMed

    Godin, D; Guimond, C; Nadeau, R A; Leblanc, A R

    1982-09-01

    The contribution of the sympathetic nervous system in the definition of various electrophysiological variables was studied in chemically sympathectomised dogs. Chemical sympathectomy was obtained following intravenous injection of 50 mg X kg-1 of 6-hydroxydopamine. Sympathectomised dogs presented significant increases in: basic sinus period, sino-atrial conduction time (SACT), AH and HV intervals of the His bundle electrogram, atrial functional (AFRP) and effective (AERP) refractory periods, atrio-ventricular node functional (AVNFRP) and effective (AVNERP) refractory periods, ventricular functional (VFRP) and effective (EVRP) refractory periods and atrial (AMAP) and ventricular (VMAP) monophasic action potential durations. Corrected sinus recovery time (CSRT) was not affected by chemical sympathectomy. Neither was the atrial ERP/MAP duration ratio. This new form of sympathectomy affects all the levels of the cardiac conduction system. Such results are in accordance with those obtained with surgical sympathectomy or the use of beta-blocking agents. PMID:6816469

  16. Rheumatoid neuropathy: a histological and electrophysiological study

    PubMed Central

    Weller, R. O.; Bruckner, F. E.; Chamberlain, M. Anne

    1970-01-01

    Peripheral nerves in five patients with rheumatoid neuropathy were examined electrophysiologically and by sural nerve biopsy. There was close correlation between the clinical severity of the disease and the degree of nerve damage found histologically and by EMG. Group 1 patients with a mild distal sensory neuropathy showed varying degrees of axonal degeneration in the large myelinated fibres and some segmental demyelination. Group 2 patients with a severe, rapidly progressive sensori-motor neuropathy had extensive loss of myelinated fibres. In one case all the large fibres had degenerated. The second case had lost both large and small myelinated fibres together with many of the non-myelinated axons. The major nerve damage in both groups appeared to be axonal degeneration but some segmental demyelination was detected. Occlusive vascular disease in the vasa nervorum was considered to be the major cause of the nerve damage. Images PMID:4320255

  17. Lyme carditis. Electrophysiologic and histopathologic study

    SciTech Connect

    Reznick, J.W.; Braunstein, D.B.; Walsh, R.L.; Smith, C.R.; Wolfson, P.M.; Gierke, L.W.; Gorelkin, L.; Chandler, F.W.

    1986-11-01

    To further define the nature of Lyme carditis, electrophysiologic study and endomyocardial biopsy were performed in a patient with Lyme disease, whose principal cardiac manifestation was high-degree atrioventricular block. Intracardiac recording demonstrated supra-Hisian block and complete absence of an escape mechanism. Gallium 67 scanning demonstrated myocardial uptake, and right ventricular endomyocardial biopsy revealed active lymphocytic myocarditis. A structure compatible with a spirochetal organism was demonstrated in one biopsy specimen. It is concluded that Lyme disease can produce active myocarditis, as suggested by gallium 67 imaging and confirmed by endomyocardial biopsy. Furthermore, the presence of high-grade atrioventricular block in this disease requires aggressive management with temporary pacemaker and corticosteroid therapy.

  18. Cardiovascular Imaging in the Electrophysiology Laboratory.

    PubMed

    Sanchis, Laura; Prat, Susanna; Sitges, Marta

    2016-06-01

    In recent years, rapid technological advances have allowed the development of new electrophysiological procedures that would not have been possible without the parallel development of imaging techniques used to plan and guide these procedures and monitor their outcomes. Ablation of atrial fibrillation is among the interventions with the greatest need for imaging support. Echocardiography allows the appropriate selection of patients and the detection of thrombi that would contraindicate the intervention; cardiac magnetic resonance imaging and computed tomography are also essential in planning this procedure, by allowing a detailed anatomical study of the pulmonary veins. In addition, in cardiac resynchronization therapy, echocardiography plays a central role in both patient selection and, later, in device adjustment and in assessing the effectiveness of the technique. More recently, ablation of ventricular tachycardias has been established as a treatment option; this would not be possible without planning using an imaging study such as cardiac magnetic resonance imaging of myocardial scarring. PMID:27107802

  19. The Acoustic Lens Design and in Vivo Use of a Multifunctional Catheter Combining Intracardiac Ultrasound Imaging and Electrophysiology Sensing

    PubMed Central

    Stephens, Douglas N.; Cannata, Jonathan; Liu, Ruibin; Zhao, Jian Zhong; Shung, K. Kirk; Nguyen, Hien; Chia, Raymond; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai E.; Mahajan, Aman; Shivkumar, Kalyanam; Kim, Kang; O’Donnell, Matthew; Sahn, David

    2009-01-01

    A multifunctional 9F intracardiac imaging and electrophysiology mapping catheter was developed and tested to help guide diagnostic and therapeutic intracardiac electrophysiology (EP) procedures. The catheter tip includes a 7.25-MHz, 64-element, side-looking phased array for high resolution sector scanning. Multiple electrophysiology mapping sensors were mounted as ring electrodes near the array for electrocardiographic synchronization of ultrasound images. The catheter array elevation beam performance in particular was investigated. An acoustic lens for the distal tip array designed with a round cross section can produce an acceptable elevation beam shape; however, the velocity of sound in the lens material should be approximately 155 m/s slower than in tissue for the best beam shape and wide bandwidth performance. To help establish the catheter’s unique ability for integration with electrophysiology interventional procedures, it was used in vivo in a porcine animal model, and demonstrated both useful intracardiac echocardiographic visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheter also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. PMID:18407850

  20. Optical stimulation enables paced electrophysiological studies in embryonic hearts

    PubMed Central

    Wang, Yves T.; Gu, Shi; Ma, Pei; Watanabe, Michiko; Rollins, Andrew M.; Jenkins, Michael W.

    2014-01-01

    Cardiac electrophysiology plays a critical role in the development and function of the heart. Studies of early embryonic electrical activity have lacked a viable point stimulation technique to pace in vitro samples. Here, optical pacing by high-precision infrared stimulation is used to pace excised embryonic hearts, allowing electrophysiological parameters to be quantified during pacing at varying rates with optical mapping. Combined optical pacing and optical mapping enables electrophysiological studies in embryos under more physiological conditions and at varying heart rates, allowing detection of abnormal conduction and comparisons between normal and pathological electrical activity during development in various models. PMID:24761284

  1. Large-scale electrophysiology: acquisition, compression, encryption, and storage of big data.

    PubMed

    Brinkmann, Benjamin H; Bower, Mark R; Stengel, Keith A; Worrell, Gregory A; Stead, Matt

    2009-05-30

    The use of large-scale electrophysiology to obtain high spatiotemporal resolution brain recordings (>100 channels) capable of probing the range of neural activity from local field potential oscillations to single-neuron action potentials presents new challenges for data acquisition, storage, and analysis. Our group is currently performing continuous, long-term electrophysiological recordings in human subjects undergoing evaluation for epilepsy surgery using hybrid intracranial electrodes composed of up to 320 micro- and clinical macroelectrode arrays. DC-capable amplifiers, sampling at 32kHz per channel with 18-bits of A/D resolution are capable of resolving extracellular voltages spanning single-neuron action potentials, high frequency oscillations, and high amplitude ultra-slow activity, but this approach generates 3 terabytes of data per day (at 4 bytes per sample) using current data formats. Data compression can provide several practical benefits, but only if data can be compressed and appended to files in real-time in a format that allows random access to data segments of varying size. Here we describe a state-of-the-art, scalable, electrophysiology platform designed for acquisition, compression, encryption, and storage of large-scale data. Data are stored in a file format that incorporates lossless data compression using range-encoded differences, a 32-bit cyclically redundant checksum to ensure data integrity, and 128-bit encryption for protection of patient information. PMID:19427545

  2. The virtual intestine: in silico modeling of small intestinal electrophysiology and motility and the applications.

    PubMed

    Du, Peng; Paskaranandavadivel, Niranchan; Angeli, Timothy R; Cheng, Leo K; O'Grady, Gregory

    2016-01-01

    The intestine comprises a long hollow muscular tube organized in anatomically and functionally discrete compartments, which digest and absorb nutrients and water from ingested food. The intestine also plays key roles in the elimination of waste and protection from infection. Critical to all of these functions is the intricate, highly coordinated motion of the intestinal tract, known as motility, which is coregulated by hormonal, neural, electrophysiological and other factors. The Virtual Intestine encapsulates a series of mathematical models of intestinal function in health and disease, with a current focus on motility, and particularly electrophysiology. The Virtual Intestine is being cohesively established across multiple physiological scales, from sub/cellular functions to whole organ levels, facilitating quantitative evaluations that present an integrative in silico framework. The models are also now finding broad physiological applications, including in evaluating hypotheses of slow wave pacemaker mechanisms, smooth muscle electrophysiology, structure-function relationships, and electromechanical coupling. Clinical applications are also beginning to follow, including in the pathophysiology of motility disorders, diagnosing intestinal ischemia, and visualizing colonic dysfunction. These advances illustrate the emerging potential of the Virtual Intestine to effectively address multiscale research challenges in interdisciplinary gastrointestinal sciences. PMID:26562482

  3. Rabbit-Specific Ventricular Model of Cardiac Electrophysiological Function including Specialized Conduction System

    PubMed Central

    Bordas, R.; Gillow, K.; Lou, Q.; Efimov, I. R.; Gavaghan, D.; Kohl, P.; Grau, V.; Rodriguez, B.

    2011-01-01

    The function of the ventricular specialized conduction system in the heart is to ensure the coordinated electrical activation of the ventricles. It is therefore critical to the overall function of the heart, and has also been implicated as an important player in various diseases, including lethal ventricular arrhythmias such as ventricular fibrillation and drug-induced torsades de pointes. However, current ventricular models of electrophysiology usually ignore, or include highly simplified representations of the specialized conduction system. Here, we describe the development of a image-based, species-consistent, anatomically-detailed model of rabbit ventricular electrophysiology that incorporates a detailed description of the free-running part of the specialized conduction system. Techniques used for the construction of the geometrical model of the specialized conduction system from a magnetic resonance dataset and integration of the system model into a ventricular anatomical model, developed from the same dataset, are described. Computer simulations of rabbit ventricular electrophysiology are conducted using the novel anatomical model and rabbit-specific membrane kinetics to investigate the importance of the components and properties of the conduction system in determining ventricular function under physiological conditions. Simulation results are compared to panoramic optical mapping experiments for model validation and results interpretation. Full access is provided to the anatomical models developed in this study. PMID:21672547

  4. Direct-growth carbon nanotubes on 3D structural microelectrodes for electrophysiological recording.

    PubMed

    Pan, Alice Ian; Lin, Min-Hsuan; Chung, Hui-Wen; Chen, Hsin; Yeh, Shih-Rung; Chuang, Yung-Jen; Chang, Yen-Chung; Yew, Tri-Rung

    2016-01-01

    A novel 3D carbon nanotube (CNT) microelectrode was developed through direct growth of CNTs on a gold pin-shaped 3D microelectrode at a low temperature (400 °C) for applications in neural and cardiac recording. With an electroplated Ni catalyst layer covering the entire surface of the pin-shaped structure, CNTs were synthesized on a 3D microelectrode by catalytic thermal chemical vapor deposition (CVD). According to the analyses by electrochemical impedance spectroscopy, the impedance of 3D microelectrodes after CNT growth and UV/O3 treatment decreased from 9.3 Ω mm(-2) to 1.2 Ω mm(-2) and the capacitance increased largely from 2.2 mF cm(-2) to 73.3 mF cm(-2). The existence of UVO3-treated CNT led to a large improvement of interfacial capacitance, contributing to the decrease of impedance. The electrophysiological detection capability of this 3D CNT microelectrode was demonstrated by the distinguished P waves, QRS complex and T waves in the electrocardiogram of the zebrafish heart and the action potential recorded from individual rat hippocampal neurons. The compatibility of integration with ICs, high resolution in space, electrophysiological signals, and non-invasive long-term recording suggest that the 3D CNT microelectrode exhibits promising potential for applications in electrophysiological research and clinical trials. PMID:26588673

  5. [Research of the visual electrophysiology record system based on DSP].

    PubMed

    Xiong, Kai; Hou, Min-Xian; Ye, Guan-Rong

    2005-03-01

    An application of digital signal processor (DSP) in the visual electrophysiology record system is presented in this paper. The system's design and implementation are described in detail. Results of its simulation and the clinical experiments are acceptable. PMID:16011113

  6. ELECTROPHYSIOLOGICAL SYSTEMS FOR NEUROTOXICITY FIELD TESTING: PEARL II AND ALTERNATIVES

    EPA Science Inventory

    Pearl II, a computerized battery of electrophysiological tests designed for neurotoxicity field testing, was developed a decade ago. he battery includes sensory evoked potentials (auditory, somatosensory and visual), event related slow brain potentials (CNV,P30O), and associated ...

  7. Electrophysiological effects of semantic context in picture and word naming.

    PubMed

    Janssen, Niels; Carreiras, Manuel; Barber, Horacio A

    2011-08-01

    Recent language production studies have started to use electrophysiological measures to investigate the time course of word selection processes. An important contribution with respect to this issue comes from studies that have relied on an effect of semantic context in the semantic blocking task. Here we used this task to further establish the empirical pattern associated with the effect of semantic context, and whether the effect arises during output processing. Electrophysiological and reaction time measures were co-registered while participants overtly named picture and word stimuli in the semantic blocking task. The results revealed inhibitory reaction time effects of semantic context for both words and pictures, and a corresponding electrophysiological effect that could not be interpreted in terms of output processes. These data suggest that the electrophysiological effect of semantic context in the semantic blocking task does not reflect output processes, and therefore undermine an interpretation of this effect in terms of word selection. PMID:21600993

  8. Multiscale Electrophysiology Format: An Open Open-source Electrophysiology Format Using Data Compression, Encryption, and Cyclic Redundancy Check

    PubMed Central

    Brinkmann, Benjamin H.; Bower, Mark R.; Stengel, Keith A.; Worrell, Gregory A.; Stead, Matt

    2010-01-01

    Continuous, long-term (up to 10 days) electrophysiological monitoring using hybrid intracranial electrodes is an emerging tool for presurgical epilepsy evaluation and fundamental investigations of seizure generation. Detection of high-frequency oscillations and microseizures could provide valuable insights into causes and therapies for the treatment of epilepsy, but requires high spatial and temporal resolution. Our group is currently using hybrid arrays composed of up to 320 micro- and clinical macroelectrode arrays sampled at 32 kHz per channel with 18-bits of A/D resolution. Such recordings produce approximately 3 terabytes of data per day. Existing file formats have limited data compression capabilities, and do not offer mechanisms for protecting patient identifying information or detecting data corruption during transmission or storage. We present a novel file format that employs range encoding to provide a high degree of data compression, a three-tiered 128-bit encryption system for patient information and data security, and a 32-bit cyclic redundancy check to verify the integrity of compressed data blocks. Open-source software to read, write, and process these files are provided. PMID:19963940

  9. Bayesian Quantitative Electrophysiology and Its Multiple Applications in Bioengineering

    PubMed Central

    Barr, Roger C.; Nolte, Loren W.; Pollard, Andrew E.

    2014-01-01

    Bayesian interpretation of observations began in the early 1700s, and scientific electrophysiology began in the late 1700s. For two centuries these two fields developed mostly separately. In part that was because quantitative Bayesian interpretation, in principle a powerful method of relating measurements to their underlying sources, often required too many steps to be feasible with hand calculation in real applications. As computer power became widespread in the later 1900s, Bayesian models and interpretation moved rapidly but unevenly from the domain of mathematical statistics into applications. Use of Bayesian models now is growing rapidly in electrophysiology. Bayesian models are well suited to the electrophysiological environment, allowing a direct and natural way to express what is known (and unknown) and to evaluate which one of many alternatives is most likely the source of the observations, and the closely related receiver operating characteristic (ROC) curve is a powerful tool in making decisions. Yet, in general, many people would ask what such models are for, in electrophysiology, and what particular advantages such models provide. So to examine this question in particular, this review identifies a number of electrophysiological papers in bio-engineering arising from questions in several organ systems to see where Bayesian electrophysiological models or ROC curves were important to the results that were achieved. PMID:22275206

  10. Electrophysiology of pumpkin seeds: Memristors in vivo.

    PubMed

    Volkov, Alexander G; Nyasani, Eunice K; Tuckett, Clayton; Greeman, Esther A; Markin, Vladislav S

    2016-01-01

    Leon Chua, the discoverer of a memristor, theoretically predicted that voltage gated ion channels can be memristors. We recently found memristors in different plants such as the Venus flytrap, Mimosa pudica, Aloe vera, apple fruits, and in potato tubers. There are no publications in literature about the existence of memristors in seeds. The goal of this work was to discover if pumpkin seeds might have memristors. We selected Cucurbita pepo L., cv. Cinderella, Cucurbita maxima L. cv Warty Goblin, and Cucurbita maxima L., cv. Jarrahdale seeds for this analysis. In these seeds, we found the presence of resistors with memory. The analysis was based on cyclic voltammetry where a memristor should manifest itself as a nonlinear two-terminal electrical element, which exhibits a pinched hysteresis loop on a current-voltage plane for any bipolar cyclic voltage input signal. Dry dormant pumpkin seeds have very high electrical resistance without memristive properties. The electrostimulation by bipolar sinusoidal or triangular periodic waves induces electrical responses in imbibed pumpkin seeds with fingerprints of memristors. Tetraethylammonium chloride, an inhibitor of voltage gated K(+) channels, transforms a memristor to a resistor in pumpkin seeds. NPPB (5-Nitro-2-(3-phenylpropylamino)benzoic acid) inhibits the memristive properties of imbibed pumpkin seeds. The discovery of memristors in pumpkin seeds creates a new direction in the understanding of electrophysiological phenomena in seeds. PMID:26926652

  11. Organic transistors for electrophysiology (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Rivnay, Jonathan

    2015-10-01

    Efficient local transduction of biological signals is of critical importance for mapping brain activity and diagnosing pathological conditions. Traditional devices used to record electrophysiological signals are passive electrodes that require (pre)amplification with downstream electronics. Organic electrochemical transistors (OECTs) that utilize conducting polymer films as the channel have shown considerable promise as amplifying transducers due to their stability in aqueous conditions and high transconductance (>3 mS). The materials properties and physics of such transistors, however, remains largely unexplored thus limiting their potential. Here we show that the uptake of ionic charge from an electrolyte into a poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) OECT channel leads to a dependence of the effective capacitance on the entire volume of the film. Subsequently, device transconductance and time response vary with channel thickness, a defining characteristic that differentiates OECTs from field effect transistors, and provides a new degree of freedom for device engineering. Using this understanding we tailor OECTs for a variety of low (1-100 Hz) and high (1-10 kHz) frequency applications, including human electroencephalography, where high transconductance devices impart richer signal content without the need for additional amplification circuitry. We also show that the materials figure of merit OECTs is the product of hole mobility and volumetric capacitance of the channel, leading to design rules for novel high performance materials.

  12. [Sudden death. Role of the electrophysiologic study].

    PubMed

    Colín Lizalde, Luis

    2002-01-01

    At present, sudden death is considered a major health problem, DeBoer in 1935, recognized the clinical importance of ventricular fibrillation as the cause of sudden cardiac death. Sudden death due to cardiovascular problems has been established as one of the main causes of death in the developed countries and in developing countries as ours, where the deaths caused by cardiovascular diseases represent 15% of the total, exceeding other causes of death. The frequency of sudden death in our country is unknown, but more frequently we hear about cases of patients that have been reanimated for cardiac arrest; in the United States of America the frequency has been estimated between 400,000 at 500,000 per year although, recently, 250,000 at 300,000 events are being mentioned. It is convenient to comment that the causal arrhythmias are diverse and may vary depending on the underlying disease, although, generally, it can be pointed out that 80% of them are due to tachyarrhythmias. It's important to point out that there is a strong relationship between left ventricular dysfunction, the frequency of ventricular arrhythmias, and fatal cardiac events due to cardiac rhythm disturbances. The recommendations for electrophysiological studies are: 1) patients surviving cardiac arrest, occurring without evidence of an acute Q-wave myocardial infarction and 2) patients surviving cardiac arrest occurring more than 48 hours after the acute phase of myocardial infarction in the absence of a recurrent ischemic event. PMID:12001869

  13. Grafted dopamine neurons: Morphology, neurochemistry, and electrophysiology.

    PubMed

    Strömberg, Ingrid; Bickford, Paula; Gerhardt, Greg A

    2010-02-01

    Grafting of dopamine-rich tissue to counteract the symptoms in Parkinson's disease became a promising tool for future treatment. This article discusses how to improve the functional outcome with respect to graft outgrowth and functions of dopamine release and electrophysiological responses to graft implantation in the host brain striatal target. It has been documented that a subpopulation of the dopamine neurons innervates the host brain in a target-specific manner, while some of the grafted dopamine neurons never project to the host striatum. Neurochemical studies have demonstrated that the graft-induced outgrowth synthesize, store, metabolize and release dopamine and possibly other neurotransmitters such as 5-HT. Furthermore, the released dopamine affects the dopamine-depleted brain in areas that are larger than the graft-derived nerve fibers reach. While stem cells will most likely be the future source of cells to be used in grafting, it is important to find the guiding cues for how to reinnervate the dopamine-depleted striatum in a proper way with respect to the dopamine subpopulations of A9 and A10 to efficiently treat the motor abnormalities seen in Parkinson's disease. PMID:19853009

  14. Electrophysiological Correlates of Emotional Responding in Schizophrenia

    PubMed Central

    Horan, William P.; Wynn, Jonathan K.; Kring, Ann M.; Simons, Robert F.; Green, Michael F.

    2010-01-01

    People with schizophrenia consistently report normal levels of pleasant emotion when exposed to evocative stimuli, suggesting intact consummatory pleasure. However, little is known about the neural correlates and time course of emotion in schizophrenia. This study used a well-validated affective picture viewing task that elicits a characteristic pattern of Event Related Potentials (ERP) from early to later processing stages (i.e., P1, P2, P3, and Late Positive Potentials (LPP)). Thirty eight stabilized schizophrenia outpatients and 36 healthy controls viewed standardized pleasant, unpleasant, and neural pictures while ERPs were recorded, and subsequently rated their emotional responses to the stimuli. Patients and controls responded to the pictures similarly in terms of their valence ratings, as well as the initial ERP components (P1, P2, and P3). However, at the later LPP component (500 – 1000 ms), patients displayed diminished electrophysiological discrimination between pleasant versus neutral stimuli. This pattern suggests that patients demonstrate normal self-reported emotional experience and intact initial sensory processing of and resource allocation to emotional stimuli. However, they show a disruption in a later component associated with sustained attentional processing of emotional stimuli. PMID:20141239

  15. Electrophysiological study in neuromuscular junction disorders.

    PubMed

    Cherian, Ajith; Baheti, Neeraj N; Iype, Thomas

    2013-01-01

    This review is on ultrastructure and subcellular physiology at normal and abnormal neuromuscular junctions. The clinical and electrophysiological findings in myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS), congenital myasthenic syndromes, and botulinum intoxication are discussed. Single fiber electromyography (SFEMG) helps to explain the basis of testing neuromuscular junction function by repetitive nerve stimulation (RNS). SFEMG requires skill and patience and its availability is limited to a few centers. For RNS supramaximal stimulation is essential and so is display of the whole waveform of each muscle response at maximum amplitude. The amplitudes of the negative phase of the first and fourth responses are measured from baseline to negative peak, and the percent change of the fourth response compared with the first represents the decrement or increment. A decrement greater than 10% is accepted as abnormal and smooth progression of response amplitude train and reproducibility form the crux. In suspected LEMS the effect of fast rates of stimulation should be determined after RNS response to slow rates of stimulation. Caution is required to avoid misinterpretation of potentiation and pseudofacilitation. PMID:23661960

  16. Cardiovascular magnetic resonance guided electrophysiology studies

    PubMed Central

    Kolandaivelu, Aravindan; Lardo, Albert C; Halperin, Henry R

    2009-01-01

    Catheter ablation is a first line treatment for many cardiac arrhythmias and is generally performed under x-ray fluoroscopy guidance. However, current techniques for ablating complex arrhythmias such as atrial fibrillation and ventricular tachycardia are associated with suboptimal success rates and prolonged radiation exposure. Pre-procedure 3D CMR has improved understanding of the anatomic basis of complex arrhythmias and is being used for planning and guidance of ablation procedures. A particular strength of CMR compared to other imaging modalities is the ability to visualize ablation lesions. Post-procedure CMR is now being applied to assess ablation lesion location and permanence with the goal of indentifying factors leading to procedure success and failure. In the future, intra-procedure real-time CMR, together with the ability to image complex 3-D arrhythmogenic anatomy and target additional ablation to regions of incomplete lesion formation, may allow for more successful treatment of even complex arrhythmias without exposure to ionizing radiation. Development of clinical grade CMR compatible electrophysiology devices is required to transition intra-procedure CMR from pre-clinical studies to more routine use in patients. PMID:19580654

  17. Electrophysiology of pumpkin seeds: Memristors in vivo

    PubMed Central

    Volkov, Alexander G.; Nyasani, Eunice K.; Tuckett, Clayton; Greeman, Esther A.; Markin, Vladislav S.

    2016-01-01

    ABSTRACT Leon Chua, the discoverer of a memristor, theoretically predicted that voltage gated ion channels can be memristors. We recently found memristors in different plants such as the Venus flytrap, Mimosa pudica, Aloe vera, apple fruits, and in potato tubers. There are no publications in literature about the existence of memristors in seeds. The goal of this work was to discover if pumpkin seeds might have memristors. We selected Cucurbita pepo L., cv. Cinderella, Cucurbita maxima L. cv Warty Goblin, and Cucurbita maxima L., cv. Jarrahdale seeds for this analysis. In these seeds, we found the presence of resistors with memory. The analysis was based on cyclic voltammetry where a memristor should manifest itself as a nonlinear two-terminal electrical element, which exhibits a pinched hysteresis loop on a current-voltage plane for any bipolar cyclic voltage input signal. Dry dormant pumpkin seeds have very high electrical resistance without memristive properties. The electrostimulation by bipolar sinusoidal or triangular periodic waves induces electrical responses in imbibed pumpkin seeds with fingerprints of memristors. Tetraethylammonium chloride, an inhibitor of voltage gated K+ channels, transforms a memristor to a resistor in pumpkin seeds. NPPB (5-Nitro-2-(3-phenylpropylamino)benzoic acid) inhibits the memristive properties of imbibed pumpkin seeds. The discovery of memristors in pumpkin seeds creates a new direction in the understanding of electrophysiological phenomena in seeds. PMID:26926652

  18. [On the first studies of electrophysiology].

    PubMed

    de Micheli, Alfredo

    2011-01-01

    A historical outline of the evolution of electrophysiology from the eighteenth century is shortly presented. Topics concerning the so called animal electricity starting from the observations on descharges of Torpedo fish until Bolognese Galvani's researches on the frogs are exposed. The points of view of their oppositionists also are examined. These ones, leaded by the physicist Alessandro Volta, professor in the University of Pavia, believed that electricity detected by galvanists was not inherent to animal but was due to the action of the metallic conductors present in the circuit: contact electricity. Only towards the middle of the nineteenth century the physicist Carlo Matteucci attained to demonstrate the existente of the real animal electricity in form of injury current. It was possible to determine that quantitatively thanks to the capillary electrometer built in 1872 by the French physicist Gabriel Lippmann. This instrument was used by the English physiologist Waller in order to obtain the primitive electrocardiographic tracings in humans (1887). At beginnings of the twentieth century, the Dutch professor Willem Einthoven, of the University of Leiden, introduced his string galvanometer which permitted to allow the modern electrocardiography. So it was possible to record the electrical potentials of myocardial cells, first in vitro, later in isolated and perfused heart, son after in dog's heart in situ and finally in human heart. Therefore now it is possible to effectuate endocardial and epicardial mappings, indispensable in order to diagnose and treat the cardiac arrhythmias. PMID:22188891

  19. Electrophysiological study of myoclonus in pediatric practice.

    PubMed

    Oguro, K; Kobayashi, J; Aiba, H; Kobayashi, S; Hojo, H

    1998-06-01

    Myoclonus can be caused from a variety of central nervous system disorders. With regard to its pathophysiology, much work has been done in adult patients, but reports from pediatric clinics are scarce. We describe the clinical and electrophysiological features of four different types of myoclonus in children using back averaging technique. In a patient with cortical reflex myoclonus, myoclonic jerks were induced in the distal right arm by taps on the ipsilateral fingers. Myoclonus was preceded by the cortical spike which was localized posterior to the central sulcus contralateral to the myoclonus, and the cortical spike was time-locked to the myoclonus. In a patient with subcortico-cortical myoclonus, myoclonus occurred as a focal motor seizure. Myoclonic jerks were preceded by generalized cortical waves which were of maximal amplitude over the cortex contralateral to the myoclonus, and cortical waves time-locked to the myoclonus. A patient with spinal myoclonus had rhythmical and segmental myoclonus. Myoclonus was induced in both arms after electrical stimulation at the wrist with a latency which was slightly longer than that of the F wave. In a patient with brainstem myoclonus, muscle activity was bilaterally synchronous and was predominant in the proximal flexors. The pattern of muscle recruitment suggested that the myoclonus signal travelled downward along the spinal cord and upward through the brainstem. The back averaging technique is essential in the differential diagnosis of myoclonus. PMID:9651693

  20. Electrophysiologic monitoring in acute brain injury.

    PubMed

    Claassen, Jan; Vespa, Paul

    2014-12-01

    To determine the optimal use and indications of electroencephalography (EEG) in critical care management of acute brain injury (ABI). An electronic literature search was conducted for articles in English describing electrophysiological monitoring in ABI from January 1990 to August 2013. A total of 165 studies were included. EEG is a useful monitor for seizure and ischemia detection. There is a well-described role for EEG in convulsive status epilepticus and cardiac arrest (CA). Data suggest EEG should be considered in all patients with ABI and unexplained and persistent altered consciousness and in comatose intensive care unit (ICU) patients without an acute primary brain condition who have an unexplained impairment of mental status. There remain uncertainties about certain technical details, e.g., the minimum duration of EEG studies, the montage, and electrodes. Data obtained from both EEG and EP studies may help estimate prognosis in ABI patients, particularly following CA and traumatic brain injury. Data supporting these recommendations is sparse, and high quality studies are needed. EEG is used to monitor and detect seizures and ischemia in ICU patients and indications for EEG are clear for certain disease states, however, uncertainty remains on other applications. PMID:25208668

  1. A Motivation Contract Model of Employee Appraisal.

    ERIC Educational Resources Information Center

    Glenn, Robert B.

    The purpose of this paper is to develop a process model for identification and assessment of employee job performance, through motivation contracting. The model integrated various components of expectancy theories of motivation and performance contracting and is based on humanistic assumptions about the nature of people. More specifically, the…

  2. Traumatic Brain Injury Detection Using Electrophysiological Methods

    PubMed Central

    Rapp, Paul E.; Keyser, David O.; Albano, Alfonso; Hernandez, Rene; Gibson, Douglas B.; Zambon, Robert A.; Hairston, W. David; Hughes, John D.; Krystal, Andrew; Nichols, Andrew S.

    2015-01-01

    Measuring neuronal activity with electrophysiological methods may be useful in detecting neurological dysfunctions, such as mild traumatic brain injury (mTBI). This approach may be particularly valuable for rapid detection in at-risk populations including military service members and athletes. Electrophysiological methods, such as quantitative electroencephalography (qEEG) and recording event-related potentials (ERPs) may be promising; however, the field is nascent and significant controversy exists on the efficacy and accuracy of the approaches as diagnostic tools. For example, the specific measures derived from an electroencephalogram (EEG) that are most suitable as markers of dysfunction have not been clearly established. A study was conducted to summarize and evaluate the statistical rigor of evidence on the overall utility of qEEG as an mTBI detection tool. The analysis evaluated qEEG measures/parameters that may be most suitable as fieldable diagnostic tools, identified other types of EEG measures and analysis methods of promise, recommended specific measures and analysis methods for further development as mTBI detection tools, identified research gaps in the field, and recommended future research and development thrust areas. The qEEG study group formed the following conclusions: (1) Individual qEEG measures provide limited diagnostic utility for mTBI. However, many measures can be important features of qEEG discriminant functions, which do show significant promise as mTBI detection tools. (2) ERPs offer utility in mTBI detection. In fact, evidence indicates that ERPs can identify abnormalities in cases where EEGs alone are non-disclosing. (3) The standard mathematical procedures used in the characterization of mTBI EEGs should be expanded to incorporate newer methods of analysis including non-linear dynamical analysis, complexity measures, analysis of causal interactions, graph theory, and information dynamics. (4) Reports of high specificity in q

  3. Electrophysiological aspects of human sphincter function

    PubMed Central

    Ustach, Thomas J.; Tobon, Fabio; Hambrecht, Terry; Bass, D. David; Schuster, Marvin M.

    1970-01-01

    In order to investigate the electrophysiology of the human internal anal sphincter and two current concepts of sphincter function, simultaneous manometric and electrical recordings were made from circular smooth muscle of the internal anal sphincter in the resting state and during reflexly induced sphincter relaxation. Three groups were studied: seven normal subjects, 25 patients with functional bowel disease, and seven patients with external sphincter paralysis due to spinal cord lesions. In the resting state slow waves of alternating potential (basic electrical rhythm or BER) were recorded in all subjects. Two types of waves were present, a constant sinusoidal pattern or a spindleshaped pattern. Either pattern was consistent for a given individual. Frequency of BER in the internal sphincter was higher than that recorded in any other gastrointestinal muscle. Our findings indicate that the BER recorded from the internal anal sphincter originates in this muscle. This activity may represent a specialized feature of sphincteric muscle since BER cannot be recorded from isolated nonsphincteric circular muscle. Reproduction of the two patterns of BER by an electronic model suggests that BER, as recorded by this technique, results from a summation of a number of electrically active cells in contact with the recording electrodes. Inhibition of BER occurred when sphincter relaxation was reflexly induced by rectal distension. Both inhibition of BER and degree of sphincter relaxation were proportional to the strength of rectal stimulation, suggesting that strength of stimulus determines the number of active cells which are inhibited. The associations of high frequency of BER with high resting pressure, and of inhibition of BER with sphincter relaxation suggests that maintenance of sphincter tone is an active process that is governed by BER. Images PMID:5409807

  4. Comparison of Electrophysiological Auditory Measures in Fishes.

    PubMed

    Maruska, Karen P; Sisneros, Joseph A

    2016-01-01

    Sounds provide fishes with important information used to mediate behaviors such as predator avoidance, prey detection, and social communication. How we measure auditory capabilities in fishes, therefore, has crucial implications for interpreting how individual species use acoustic information in their natural habitat. Recent analyses have highlighted differences between behavioral and electrophysiologically determined hearing thresholds, but less is known about how physiological measures at different auditory processing levels compare within a single species. Here we provide one of the first comparisons of auditory threshold curves determined by different recording methods in a single fish species, the soniferous Hawaiian sergeant fish Abudefduf abdominalis, and review past studies on representative fish species with tuning curves determined by different methods. The Hawaiian sergeant is a colonial benthic-spawning damselfish (Pomacentridae) that produces low-frequency, low-intensity sounds associated with reproductive and agonistic behaviors. We compared saccular potentials, auditory evoked potentials (AEP), and single neuron recordings from acoustic nuclei of the hindbrain and midbrain torus semicircularis. We found that hearing thresholds were lowest at low frequencies (~75-300 Hz) for all methods, which matches the spectral components of sounds produced by this species. However, thresholds at best frequency determined via single cell recordings were ~15-25 dB lower than those measured by AEP and saccular potential techniques. While none of these physiological techniques gives us a true measure of the auditory "perceptual" abilities of a naturally behaving fish, this study highlights that different methodologies can reveal similar detectable range of frequencies for a given species, but absolute hearing sensitivity may vary considerably. PMID:26515317

  5. OptoDyCE: Automated system for high-throughput all-optical dynamic cardiac electrophysiology

    NASA Astrophysics Data System (ADS)

    Klimas, Aleksandra; Yu, Jinzhu; Ambrosi, Christina M.; Williams, John C.; Bien, Harold; Entcheva, Emilia

    2016-02-01

    In the last two decades, <30% of drugs withdrawals from the market were due to cardiac toxicity, where unintended interactions with ion channels disrupt the heart's normal electrical function. Consequently, all new drugs must undergo preclinical testing for cardiac liability, adding to an already expensive and lengthy process. Recognition that proarrhythmic effects often result from drug action on multiple ion channels demonstrates a need for integrative and comprehensive measurements. Additionally, patient-specific therapies relying on emerging technologies employing stem-cell derived cardiomyocytes (e.g. induced pluripotent stem-cell-derived cardiomyocytes, iPSC-CMs) require better screening methods to become practical. However, a high-throughput, cost-effective approach for cellular cardiac electrophysiology has not been feasible. Optical techniques for manipulation and recording provide a contactless means of dynamic, high-throughput testing of cells and tissues. Here, we consider the requirements for all-optical electrophysiology for drug testing, and we implement and validate OptoDyCE, a fully automated system for all-optical cardiac electrophysiology. We demonstrate the high-throughput capabilities using multicellular samples in 96-well format by combining optogenetic actuation with simultaneous fast high-resolution optical sensing of voltage or intracellular calcium. The system can also be implemented using iPSC-CMs and other cell-types by delivery of optogenetic drivers, or through the modular use of dedicated light-sensitive somatic cells in conjunction with non-modified cells. OptoDyCE provides a truly modular and dynamic screening system, capable of fully-automated acquisition of high-content information integral for improved discovery and development of new drugs and biologics, as well as providing a means of better understanding of electrical disturbances in the heart.

  6. Dynamic clamp: a powerful tool in cardiac electrophysiology.

    PubMed

    Wilders, Ronald

    2006-10-15

    Dynamic clamp is a collection of closely related techniques that have been employed in cardiac electrophysiology to provide direct answers to numerous research questions regarding basic cellular mechanisms of action potential formation, action potential transfer and action potential synchronization in health and disease. Building on traditional current clamp, dynamic clamp was initially used to create virtual gap junctions between isolated myocytes. More recent applications include the embedding of a real pacemaking myocyte in a simulated network of atrial or ventricular cells and the insertion of virtual ion channels, either simulated in real time or simultaneously recorded from an expression system, into the membrane of an isolated myocyte. These applications have proven that dynamic clamp, which is characterized by the real-time evaluation and injection of simulated membrane current, is a powerful tool in cardiac electrophysiology. Here, each of the three different experimental configurations used in cardiac electrophysiology is reviewed. Also, directions are given for the implementation of dynamic clamp in the cardiac electrophysiology laboratory. With the growing interest in the application of dynamic clamp in cardiac electrophysiology, it is anticipated that dynamic clamp will also prove to be a powerful tool in basic research on biological pacemakers and in identification of specific ion channels as targets for drug development. PMID:16873403

  7. Electrophysiological measures of cognition in biological psychiatry: some cautionary notes.

    PubMed

    Barceló, F; Gale, A

    1997-12-01

    Research into the electrophysiological correlates of mental illness is currently expanding, largely because of the availability of relatively inexpensive and powerful computers. However, improvements in technology do not always lead to enhanced methodological procedures; thus, there are concerns over the proper interpretation of the results of these investigations. Our argument is that electroencephalographic (EEG) research into psychopathology of psychiatric diseases should adopt a cognitivist model of mental dysfunction rather than a neurologist model of brain disease. Cognitive science has significant potential as an integrative framework for theorizing and researching psychiatric disorders and their treatment. Models of human cognitive functioning have rather special and unique features; these will make their impact upon the nature of both the analysis and interpretation of EEG data. The adoption of a sound model of brain function has implications for the methods to be used at different successive stages of the research process. We address a number of methodological requirements pertaining to: the recording and analysis of EEG signals, the laboratory context, the nature of the tasks, and the attribution of obtained effects. However, there are grounds for great caution. Even if the mapping of electrical changes in brain activity leads to a good approximation of the temporal and spatial dynamics of higher brain function, exploitation of such information presupposes a deeper understanding of both human cognition and the physiological basis of the EEG than is often displayed in the literature. To demonstrate this fundamental point, we draw a number of comparisons between traditional neurological approaches to brain assessment and contemporary cognitive psychophysiology. PMID:9522268

  8. Electrophysiological Signal Analysis and Visualization using Cloudwave for Epilepsy Clinical Research

    PubMed Central

    Jayapandian, Catherine P.; Chen, Chien-Hung; Bozorgi, Alireza; Lhatoo, Samden D.; Zhang, Guo-Qiang; Sahoo, Satya S.

    2015-01-01

    Epilepsy is the most common serious neurological disorder affecting 50–60 million persons worldwide. Electrophysiological data recordings, such as electroencephalogram (EEG), are the gold standard for diagnosis and pre-surgical evaluation in epilepsy patients. The increasing trend towards multi-center clinical studies require signal visualization and analysis tools to support real time interaction with signal data in a collaborative environment, which are cannot be supported by traditional desktop-based standalone applications. As part of the Prevention and Risk Identification of SUDEP Mortality (PRISM) project, we have developed a Web-based electrophysiology data visualization and analysis platform called Cloudwave using highly scalable open source cloud computing infrastructure. Cloudwave is integrated with the PRISM patient cohort identification tool called MEDCIS (Multi-modality Epilepsy Data Capture and Integration System). The Epilepsy and Seizure Ontology (EpSO) underpins both Cloudwave and MEDCIS to support query composition and result retrieval. Cloudwave is being used by clinicians and research staff at the University Hospital - Case Medical Center (UH-CMC) Epilepsy Monitoring Unit (EMU) and will be progressively deployed at four EMUs in the United States and the United Kingdom as part of the PRISM project. PMID:23920671

  9. Natural stimuli from three coherent modalities enhance behavioral responses and electrophysiological cortical activity in humans.

    PubMed

    Sella, Irit; Reiner, Miriam; Pratt, Hillel

    2014-07-01

    Cues that involve a number of sensory modalities are processed in the brain in an interactive multimodal manner rather than independently for each modality. We studied multimodal integration in a natural, yet fully controlled scene, implemented as an interactive game in an auditory-haptic-visual virtual environment. In this imitation of a natural scene, the targets of perception were ecologically valid uni-, bi- and tri-modal manifestations of a simple event-a ball hitting a wall. Subjects were engaged in the game while their behavioral and early cortical electrophysiological responses were measured. Behavioral results confirmed that tri-modal cues were detected faster and more accurately than bi-modal cues, which, likewise, showed advantages over unimodal responses. Event-Related Potentials (ERPs) were recorded, and the first 200 ms following stimulus onset was analyzed to reveal the latencies of cortical multimodal interactions as estimated by sLORETA. These electrophysiological findings indicated bi-modal as well as tri-modal interactions beginning very early (~30 ms), uniquely for each multimodal combination. The results suggest that early cortical multimodal integration accelerates cortical activity and, in turn, enhances performance measures. This acceleration registers on the scalp as sub-additive cortical activation. PMID:24315926

  10. Optrodes for combined optogenetics and electrophysiology in live animals

    PubMed Central

    Dufour, Suzie; De Koninck, Yves

    2015-01-01

    Abstract. Optical tissue properties limit visible light depth penetration in tissue. Because of this, the recent development of optogenetic tools was quickly followed by the development of light delivery devices for in vivo optogenetics applications. We summarize the efforts made in the last decade to design neural probes that combine conventional electrophysiological recordings and optical channel(s) for optogenetic activation, often referred to as optodes or optrodes. Several aspects including challenges for light delivery in living brain tissue, the combination of light delivery with electrophysiological recordings, probe designs, multimodality, wireless implantable system, and practical considerations guiding the choice of configuration depending on the questions one seeks to address are presented. PMID:26158014

  11. An electrophysiological study of the intermediate syndrome of organophosphate poisoning.

    PubMed

    Lorenzoni, Paulo José; Gasparetto, Juliano; Kay, Cláudia Suemi Kamoi; Scola, Rosana Herminia; Werneck, Lineu César

    2010-09-01

    Acute organophosphate (OP) poisoning is commonly seen in emergency medicine. Neurologists must be alert to detect neuromuscular transmission failure and other neurological complications that follow OP poisoning. We report a 37-year-old male with acute OP poisoning to emphasize the electrophysiological abnormalities during the intermediate syndrome (IMS). Motor nerve conduction studies revealed that a single nerve stimulation evoked a repetitive compound muscle action potential, whereas repetitive nerve stimulation resulted in a combination of a decrement-increment pattern and a repetitive fade response. Thus, electrophysiological studies can be used to monitor patients with IMS, and these test results correlate well with clinical findings in acute OP poisoning. PMID:20483619

  12. Clinical and electrophysiological assessment of inferior alveolar nerve function after lateral nerve transposition.

    PubMed

    Nocini, P F; De Santis, D; Fracasso, E; Zanette, G

    1999-04-01

    Inferior alveolar nerve (IAN) transposition surgery may cause some degree of sensory impairment. Accurate and reproducible tests are mandatory to assess IAN conduction capacity following nerve transposition. In this study subjective (heat, pain and tactile-discriminative tests) and objective (electrophysiological) assessments were performed in 10 patients receiving IAN transposition (bilaterally in 8 cases) in order to evaluate any impairment of the involved nerves one year post-operatively. All patients reported a tingling, well-tolerated sensation in the areas supplied by the mental nerve with no anaesthesia or burning paresthesia. Tactile discrimination was affected the most (all but 1 patient). No action potential was recorded in 4 patients' sides (23.5%); 12 sides showed a decreased nerve conduction velocity (NCV) (70.5%) and 1 side normal NCV values (6%). There was no significant difference in NCV decrease between partial and total transposition sides, if examined separately. Nerve conduction findings were related 2-point discrimination scores, but not to changes in pain and heat sensitivity. These findings show that lateral nerve transposition, though resulting in a high percentage of minor IAN injuries, as determined by electrophysiological testing, provides a viable surgical procedure to allow implant placement in the posterior mandible without causing severe sensory complaints. Considering ethical and forensic implications, patients should be fully informed that a certain degree of nerve injury might be expected to occur from the procedure. Electrophysiological evaluation is a reliable way to assess the degree of IAN dysfunction, especially if combined with a clinical examination. Intraoperative monitoring of IAN conduction might help identify the pathogenetic mechanisms of nerve injury and the surgical steps that are most likely to harm nerve integrity. PMID:10219131

  13. Electrophysiological correlates of the BOLD signal for EEG-informed fMRI

    PubMed Central

    Murta, Teresa; Leite, Marco; Carmichael, David W; Figueiredo, Patrícia; Lemieux, Louis

    2015-01-01

    Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) are important tools in cognitive and clinical neuroscience. Combined EEG–fMRI has been shown to help to characterise brain networks involved in epileptic activity, as well as in different sensory, motor and cognitive functions. A good understanding of the electrophysiological correlates of the blood oxygen level-dependent (BOLD) signal is necessary to interpret fMRI maps, particularly when obtained in combination with EEG. We review the current understanding of electrophysiological–haemodynamic correlates, during different types of brain activity. We start by describing the basic mechanisms underlying EEG and BOLD signals and proceed by reviewing EEG-informed fMRI studies using fMRI to map specific EEG phenomena over the entire brain (EEG–fMRI mapping), or exploring a range of EEG-derived quantities to determine which best explain colocalised BOLD fluctuations (local EEG–fMRI coupling). While reviewing studies of different forms of brain activity (epileptic and nonepileptic spontaneous activity; cognitive, sensory and motor functions), a significant attention is given to epilepsy because the investigation of its haemodynamic correlates is the most common application of EEG-informed fMRI. Our review is focused on EEG-informed fMRI, an asymmetric approach of data integration. We give special attention to the invasiveness of electrophysiological measurements and the simultaneity of multimodal acquisitions because these methodological aspects determine the nature of the conclusions that can be drawn from EEG-informed fMRI studies. We emphasise the advantages of, and need for, simultaneous intracranial EEG–fMRI studies in humans, which recently became available and hold great potential to improve our understanding of the electrophysiological correlates of BOLD fluctuations. PMID:25277370

  14. Electrophysiological Modeling of Cardiac Ventricular Function: From Cell to Organ

    PubMed Central

    Winslow, R. L.; Scollan, D. F.; Holmes, A.; Yung, C. K.; Zhang, J.; Jafri, M. S.

    2005-01-01

    Three topics of importance to modeling the integrative function of the heart are reviewed. The first is modeling of the ventricular myocyte. Emphasis is placed on excitation-contraction coupling and intracellular Ca2+ handling, and the interpretation of experimental data regarding interval-force relationships. Second, data on use of diffusion tensor magnetic resonance (DTMR) imaging for measuring the anatomical structure of the cardiac ventricles are presented. A method for the semi-automated reconstruction of the ventricles using a combination of gradient recalled acquisition in the steady state (GRASS) and DTMR images is described. Third, we describe how these anatomically and biophysically based models of the cardiac ventricles can be implemented on parallel computers. PMID:11701509

  15. Electrophysiological features of POEMS syndrome and chronic inflammatory demyelinating polyneuropathy.

    PubMed

    Guo, Xiuming; Qin, Xinyue; Zhang, Yuping; Huang, Cheng; Yu, Gang

    2014-04-01

    Polyneuropathy is often an initial manifestation of polyneuropathy, organomegaly, endocrinopathy, M protein and skin changes (POEMS) syndrome and therefore this disorder is frequently misdiagnosed as chronic inflammatory demyelinating polyneuropathy (CIDP). We reviewed electrophysiological data in 20 patients with POEMS syndrome and 36 matched patients with CIDP to compare the electrophysiological features of POEMS syndrome and CIDP. Compared with CIDP controls, POEMS patients demonstrated (1) less prolonged distal motor latency and less reduced motor nerve and sensory nerve conduction velocities, (2) greater reduction of amplitudes of compound motor action potentials (CMAP) in distal stimulation, and similar reduction of amplitudes of CMAP in proximal stimulation, (3) similar reduction of amplitudes of sensory nerve action potentials (SNAP) in median and ulnar nerves, and a greater reduction of amplitudes of SNAP in tibial and peroneal nerves, (4) less temporal dispersion, (5) less frequent conduction block, (6) more frequent neurogenic injury in the muscles of the upper and lower limbs, and more frequent neurogenic injury in the muscles of the lower than upper limbs, (7) similar F wave and H reflex abnormalities, and (8) less frequent skin sympathetic response abnormalities. We concluded that before development of typical clinical manifestations, POEMS neuropathy can be distinguished from CIDP by neural electrophysiological examination. These electrophysiological features can be used for early diagnosis and initiating correct treatment of POEMS syndrome. PMID:24268501

  16. A highly versatile and easily configurable system for plant electrophysiology.

    PubMed

    Gunsé, Benet; Poschenrieder, Charlotte; Rankl, Simone; Schröeder, Peter; Rodrigo-Moreno, Ana; Barceló, Juan

    2016-01-01

    In this study we present a highly versatile and easily configurable system for measuring plant electrophysiological parameters and ionic flow rates, connected to a computer-controlled highly accurate positioning device. The modular software used allows easy customizable configurations for the measurement of electrophysiological parameters. Both the operational tests and the experiments already performed have been fully successful and rendered a low noise and highly stable signal. Assembly, programming and configuration examples are discussed. The system is a powerful technique that not only gives precise measuring of plant electrophysiological status, but also allows easy development of ad hoc configurations that are not constrained to plant studies. •We developed a highly modular system for electrophysiology measurements that can be used either in organs or cells and performs either steady or dynamic intra- and extracellular measurements that takes advantage of the easiness of visual object-oriented programming.•High precision accuracy in data acquisition under electrical noisy environments that allows it to run even in a laboratory close to electrical equipment that produce electrical noise.•The system makes an improvement of the currently used systems for monitoring and controlling high precision measurements and micromanipulation systems providing an open and customizable environment for multiple experimental needs. PMID:27298766

  17. The Electrophysiological Correlates of Scientific Innovation Induced by Heuristic Information

    ERIC Educational Resources Information Center

    Luo, Junlong; Du, Xiumin; Tang, Xiaochen; Zhang, Entao; Li, Haijiang; Zhang, Qinglin

    2013-01-01

    In this study, novel and old scientific innovations (NSI and OSI) were selected as materials to explore the electrophysiological correlates of scientific innovation induced by heuristic information. Using event-related brain potentials (ERPs) to do so, college students solved NSI problems (for which they did not know the answers) and OSI problems…

  18. Function and modulation of bacterial porins: insights from electrophysiology.

    PubMed

    Delcour, A H

    1997-06-15

    Electrophysiological techniques provide a wealth of information regarding the molecular mechanisms that underlie the function and modulation of ion channels. They have revealed that bacterial porins do not behave as static, permanently open pores but display a much more complex and dynamic behavior than anticipated from non-electrophysiological studies. The channels switch between short-lived open and closed conformations (gating activity), and can also remain in an inactivated, non-ion conducting state for prolonged periods of time. Thus the role of porins is not limited to that of a molecular filter, but is extended to the control of outer membrane permeability through the regulation of their activity. Electrophysiological studies have indeed demonstrated that both gating and inactivation are modulated by a variety of physical and chemical parameters and are highly cooperative phenomena, often involving numerous channels working in concert. Cooperativity acts as an amplification mechanism that grants a large population of porins, such as found in the outer membrane, with sensitivity to modulation by external or internal factors. By conferring permeability properties to the outer membrane, porins play a crucial role in the bacterium's antibiotic susceptibility and survival in various environmental conditions. The detailed information that electrophysiology only can provide on porin function and modulation promises to yield a more accurate description of how porin properties can be used by cells to adapt to a changing environment, and to offer mechanisms that might optimize the drug sensitivity of the microorganism. PMID:9228742

  19. Electrophysiological Signals of Familiarity and Recency in the Infant Brain

    ERIC Educational Resources Information Center

    Snyder, Kelly A.; Garza, John; Zolot, Liza; Kresse, Anna

    2010-01-01

    Electrophysiological work in nonhuman primates has established the existence of multiple types of signals in the temporal lobe that contribute to recognition memory, including information regarding a stimulus's relative novelty, familiarity, and recency of occurrence. We used high-density event-related potentials (ERPs) to examine whether young…

  20. Electrophysiological Monitoring of Brain Injury and Recovery after Cardiac Arrest

    PubMed Central

    Deng, Ruoxian; Xiong, Wei; Jia, Xiaofeng

    2015-01-01

    Reliable prognostic methods for cerebral functional outcome of post cardiac-arrest (CA) patients are necessary, especially since therapeutic hypothermia (TH) as a standard treatment. Traditional neurophysiological prognostic indicators, such as clinical examination and chemical biomarkers, may result in indecisive outcome predictions and do not directly reflect neuronal activity, though they have remained the mainstay of clinical prognosis. The most recent advances in electrophysiological methods—electroencephalography (EEG) pattern, evoked potential (EP) and cellular electrophysiological measurement—were developed to complement these deficiencies, and will be examined in this review article. EEG pattern (reactivity and continuity) provides real-time and accurate information for early-stage (particularly in the first 24 h) hypoxic-ischemic (HI) brain injury patients with high sensitivity. However, the signal is easily affected by external stimuli, thus the measurements of EP should be combined with EEG background to validate the predicted neurologic functional result. Cellular electrophysiology, such as multi-unit activity (MUA) and local field potentials (LFP), has strong potential for improving prognostication and therapy by offering additional neurophysiologic information to understand the underlying mechanisms of therapeutic methods. Electrophysiology provides reliable and precise prognostication on both global and cellular levels secondary to cerebral injury in cardiac arrest patients treated with TH. PMID:26528970

  1. Arrhythmogenesis Research: A Perspective from Computational Electrophysiology Viewpoint

    PubMed Central

    Trayanova, Natalia; Plank, Gernot

    2012-01-01

    The mechanisms by which arrhythmias are generated in the heart remains a field of intensive research. Recent advances in computational biology and electrophysiology have enabled researchers to use an alternative tool in the study of arrhythmia mechanisms, the multi-scale modeling and simulation of cardiac arrhythmogenesis at the organ level. This article reviews the recent advances and achievements using this approach. PMID:18001976

  2. A heated stage and tissue culture chamber for electrophysiology.

    PubMed

    Bonkowski, L; Runion, H I

    1976-12-15

    A simple, inexpensive heating circuit is described for use with a warmed microscope stage, small tissue bath, and heated tissue culture chamber. A major consideration in the design of the apparatus is a compatability with electrophysiological studies. Thus, proper shielding and low profile for microelectrode positioning are featured. PMID:1021472

  3. Combining single-molecule imaging and single-channel electrophysiology.

    PubMed

    Weatherill, Eve E; Wallace, Mark I

    2015-01-16

    Combining simultaneous single-molecule fluorescence measurements of ion channel conformational change with single-channel electrophysiology would enable a direct link between structure and function. Such methods would help us to create a truly molecular "movie" of how these important biomolecules work. Here we review past and recent progress toward this goal. PMID:25026065

  4. Age-Related Changes in 1/f Neural Electrophysiological Noise

    PubMed Central

    Kramer, Mark A.; Case, John; Lepage, Kyle Q.; Tempesta, Zechari R.; Knight, Robert T.; Gazzaley, Adam

    2015-01-01

    Aging is associated with performance decrements across multiple cognitive domains. The neural noise hypothesis, a dominant view of the basis of this decline, posits that aging is accompanied by an increase in spontaneous, noisy baseline neural activity. Here we analyze data from two different groups of human subjects: intracranial electrocorticography from 15 participants over a 38 year age range (15–53 years) and scalp EEG data from healthy younger (20–30 years) and older (60–70 years) adults to test the neural noise hypothesis from a 1/f noise perspective. Many natural phenomena, including electrophysiology, are characterized by 1/f noise. The defining characteristic of 1/f is that the power of the signal frequency content decreases rapidly as a function of the frequency (f) itself. The slope of this decay, the noise exponent (χ), is often <−1 for electrophysiological data and has been shown to approach white noise (defined as χ = 0) with increasing task difficulty. We observed, in both electrophysiological datasets, that aging is associated with a flatter (more noisy) 1/f power spectral density, even at rest, and that visual cortical 1/f noise statistically mediates age-related impairments in visual working memory. These results provide electrophysiological support for the neural noise hypothesis of aging. SIGNIFICANCE STATEMENT Understanding the neurobiological origins of age-related cognitive decline is of critical scientific, medical, and public health importance, especially considering the rapid aging of the world's population. We find, in two separate human studies, that 1/f electrophysiological noise increases with aging. In addition, we observe that this age-related 1/f noise statistically mediates age-related working memory decline. These results significantly add to this understanding and contextualize a long-standing problem in cognition by encapsulating age-related cognitive decline within a neurocomputational model of 1/f noise

  5. Software and hardware infrastructure for research in electrophysiology

    PubMed Central

    Mouček, Roman; Ježek, Petr; Vařeka, Lukáš; Řondík, Tomáš; Brůha, Petr; Papež, Václav; Mautner, Pavel; Novotný, Jiří; Prokop, Tomáš; Štěbeták, Jan

    2014-01-01

    As in other areas of experimental science, operation of electrophysiological laboratory, design and performance of electrophysiological experiments, collection, storage and sharing of experimental data and metadata, analysis and interpretation of these data, and publication of results are time consuming activities. If these activities are well organized and supported by a suitable infrastructure, work efficiency of researchers increases significantly. This article deals with the main concepts, design, and development of software and hardware infrastructure for research in electrophysiology. The described infrastructure has been primarily developed for the needs of neuroinformatics laboratory at the University of West Bohemia, the Czech Republic. However, from the beginning it has been also designed and developed to be open and applicable in laboratories that do similar research. After introducing the laboratory and the whole architectural concept the individual parts of the infrastructure are described. The central element of the software infrastructure is a web-based portal that enables community researchers to store, share, download and search data and metadata from electrophysiological experiments. The data model, domain ontology and usage of semantic web languages and technologies are described. Current data publication policy used in the portal is briefly introduced. The registration of the portal within Neuroscience Information Framework is described. Then the methods used for processing of electrophysiological signals are presented. The specific modifications of these methods introduced by laboratory researches are summarized; the methods are organized into a laboratory workflow. Other parts of the software infrastructure include mobile and offline solutions for data/metadata storing and a hardware stimulator communicating with an EEG amplifier and recording software. PMID:24639646

  6. Virtual Electrophysiological Study of Atrial Fibrillation in Fibrotic Remodeling

    PubMed Central

    McDowell, Kathleen S.; Zahid, Sohail; Vadakkumpadan, Fijoy; Blauer, Joshua; MacLeod, Rob S.; Trayanova, Natalia A.

    2015-01-01

    Research has indicated that atrial fibrillation (AF) ablation failure is related to the presence of atrial fibrosis. However it remains unclear whether this information can be successfully used in predicting the optimal ablation targets for AF termination. We aimed to provide a proof-of-concept that patient-specific virtual electrophysiological study that combines i) atrial structure and fibrosis distribution from clinical MRI and ii) modeling of atrial electrophysiology, could be used to predict: (1) how fibrosis distribution determines the locations from which paced beats degrade into AF; (2) the dynamic behavior of persistent AF rotors; and (3) the optimal ablation targets in each patient. Four MRI-based patient-specific models of fibrotic left atria were generated, ranging in fibrosis amount. Virtual electrophysiological studies were performed in these models, and where AF was inducible, the dynamics of AF were used to determine the ablation locations that render AF non-inducible. In 2 of the 4 models patient-specific models AF was induced; in these models the distance between a given pacing location and the closest fibrotic region determined whether AF was inducible from that particular location, with only the mid-range distances resulting in arrhythmia. Phase singularities of persistent rotors were found to move within restricted regions of tissue, which were independent of the pacing location from which AF was induced. Electrophysiological sensitivity analysis demonstrated that these regions changed little with variations in electrophysiological parameters. Patient-specific distribution of fibrosis was thus found to be a critical component of AF initiation and maintenance. When the restricted regions encompassing the meander of the persistent phase singularities were modeled as ablation lesions, AF could no longer be induced. The study demonstrates that a patient-specific modeling approach to identify non-invasively AF ablation targets prior to the clinical

  7. Animal electricity and the birth of electrophysiology: the legacy of Luigi Galvani.

    PubMed

    Piccolino, M

    1998-07-15

    Preceded by a companion paper on Galvani's life, this article is written on the occasion of the bicentenary of the death of Luigi Galvani. From his studies on the effects of electricity on frogs, the scientist of Bologna derived the hypothesis that animal tissues are endowed with an intrinsic electricity that is involved in fundamental physiological processes such as nerve conduction and muscle contraction. Galvani's work swept away from life sciences mysterious fluids and elusive entities like "animal spirits" and led to the foundation of a new science, electrophysiology. Two centuries of research work have demonstrated how insightful was Galvani's conception of animal electricity. Nevertheless, the scholar of Bologna is still largely misrepresented in the history of science, because the importance of his researches seems to be limited to the fact that they opened the paths to the studies of the physicist Alessandro Volta, which culminated in 1800 with the invention of the electric battery. Volta strongly opposed Galvani's theories on animal electricity. The matter of the scientific controversy between Galvani and Volta is examined here in the light of two centuries of electrophysiological studies leading to the modern understanding of electrical excitability in nerve and muscle. By surveying the work of scientists such as Nobili, Matteucci, du Bois-Reymond, von Helmholtz, Bernstein, Hermann, Lucas, Adrian, Hodgkin, Huxley, and Katz, the real matter of the debate raised by Galvani's discoveries is here reconsidered. In addition, a revolutionary phase of the 18th century science that opened the way for the development of modern neurosciences is reevaluated. PMID:9739001

  8. Russian Teaching Contracts.

    ERIC Educational Resources Information Center

    Stevens, Betsy

    2000-01-01

    Analyzes two Russian teaching contracts, rhetorically comparing purpose and audience, culture, gender, and the role of the individual versus the state. Uses anecdotal episodes as a framework for examining Russian culture and analyzing university teaching contracts, concluding that the contracts are not only brief and factual but also reflect a…

  9. Teaching about Contracts.

    ERIC Educational Resources Information Center

    Froman, Michael; Kosnoff, Kathy

    1978-01-01

    Presents teaching strategies for introducing high school students to contract law. Offers as a case study a contract agreement between pro football players and team owners. Stresses basic elements of contracts (offer, acceptance, consideration, and understanding the bargaining process). Journal available from the American Bar Association, 1155…

  10. The Joy of Contracts.

    ERIC Educational Resources Information Center

    Hegarty, Kevin

    This paper is a practical guide that explains and illustrates contracts between libraries and vendors for computerized circulation systems. It describes the elements of a typical contract to include the equipment and services that should be specified in the contract and establishes scheduling and acceptance testing needs. Included in a contract…

  11. Systematic characterization of the ionic basis of rabbit cellular electrophysiology using two ventricular models.

    PubMed

    Romero, Lucía; Carbonell, Beatriz; Trenor, Beatriz; Rodríguez, Blanca; Saiz, Javier; Ferrero, José M

    2011-10-01

    Several mathematical models of rabbit ventricular action potential (AP) have been proposed to investigate mechanisms of arrhythmias and excitation-contraction coupling. Our study aims at systematically characterizing how ionic current properties modulate the main cellular biomarkers of arrhythmic risk using two widely-used rabbit ventricular models, and comparing simulation results using the two models with experimental data available for rabbit. A sensitivity analysis of AP properties, Ca²⁺ and Na⁺ dynamics, and their rate dependence to variations (±15% and ±30%) in the main transmembrane current conductances and kinetics was performed using the Shannon et al. (2004) and the Mahajan et al. (2008a,b) AP rabbit models. The effects of severe transmembrane current blocks (up to 100%) on steady-state AP and calcium transients, and AP duration (APD) restitution curves were also simulated using both models. Our simulations show that, in both virtual rabbit cardiomyocytes, APD is significantly modified by most repolarization currents, AP triangulation is regulated mostly by the inward rectifier K⁺ current (I(K1)) whereas APD rate adaptation as well as [Na⁺](i) rate dependence is influenced by the Na⁺/K⁺ pump current (I(NaK)). In addition, steady-state [Ca²⁺](i) levels, APD restitution properties and [Ca²⁺](i) rate dependence are strongly dependent on I(NaK), the L-Type Ca²⁺ current (I(CaL)) and the Na⁺/Ca²⁺ exchanger current (I(NaCa)), although the relative role of these currents is markedly model dependent. Furthermore, our results show that simulations using both models agree with many experimentally-reported electrophysiological characteristics. However, our study shows that the Shannon et al. model mimics rabbit electrophysiology more accurately at normal pacing rates, whereas Mahajan et al. model behaves more appropriately at faster rates. Our results reinforce the usefulness of sensitivity analysis for further understanding of cellular

  12. The contribution of electrophysiology to knowledge of the acute and chronic effects of ethanol.

    PubMed

    Little, H J

    1999-12-01

    This review describes the effects of ethanol on the components of neuronal transmission and the relationship of such effects to the behavioural actions of ethanol. The concentrations of ethanol with acute actions on voltage-sensitive ion channels are first described, then the actions of ethanol on ligand-gated ion channels, including those controlled by cholinergic receptors, 5-hydroxytryptamine receptors, the various excitatory amino acid receptors, and gamma-aminobutyric acid receptors. Acute effects of ethanol are then described on brain areas thought to be involved in arousal and attention, the reinforcing effects of ethanol, the production of euphoria, the actions of ethanol on motor control, and the amnesic effects of ethanol; the acute effects of ethanol demonstrated by EEG studies are also discussed. Chronic effects of alcohol on neuronal transmission are described in the context of the various components of the ethanol withdrawal syndrome, withdrawal hyperexcitability, dysphoria and anhedonia, withdrawal anxiety, craving, and relapse drinking. Electrophysiological studies on the genetic influences on the effects of ethanol are discussed, particularly the acute actions of ethanol and electrophysiological differences reported in individuals predisposed to alcoholism. The conclusion notes the concentration of studies on the classical transmitters, with relative neglect of the effects of ethanol on peptides and on neuronal interactions between brain areas and integrated patterns of neuronal activity. PMID:10665833

  13. Cloudwave: distributed processing of "big data" from electrophysiological recordings for epilepsy clinical research using Hadoop.

    PubMed

    Jayapandian, Catherine P; Chen, Chien-Hung; Bozorgi, Alireza; Lhatoo, Samden D; Zhang, Guo-Qiang; Sahoo, Satya S

    2013-01-01

    Epilepsy is the most common serious neurological disorder affecting 50-60 million persons worldwide. Multi-modal electrophysiological data, such as electroencephalography (EEG) and electrocardiography (EKG), are central to effective patient care and clinical research in epilepsy. Electrophysiological data is an example of clinical "big data" consisting of more than 100 multi-channel signals with recordings from each patient generating 5-10GB of data. Current approaches to store and analyze signal data using standalone tools, such as Nihon Kohden neurology software, are inadequate to meet the growing volume of data and the need for supporting multi-center collaborative studies with real time and interactive access. We introduce the Cloudwave platform in this paper that features a Web-based intuitive signal analysis interface integrated with a Hadoop-based data processing module implemented on clinical data stored in a "private cloud". Cloudwave has been developed as part of the National Institute of Neurological Disorders and Strokes (NINDS) funded multi-center Prevention and Risk Identification of SUDEP Mortality (PRISM) project. The Cloudwave visualization interface provides real-time rendering of multi-modal signals with "montages" for EEG feature characterization over 2TB of patient data generated at the Case University Hospital Epilepsy Monitoring Unit. Results from performance evaluation of the Cloudwave Hadoop data processing module demonstrate one order of magnitude improvement in performance over 77GB of patient data. (Cloudwave project: http://prism.case.edu/prism/index.php/Cloudwave). PMID:24551370

  14. Neural ensemble communities: open-source approaches to hardware for large-scale electrophysiology.

    PubMed

    Siegle, Joshua H; Hale, Gregory J; Newman, Jonathan P; Voigts, Jakob

    2015-06-01

    One often-overlooked factor when selecting a platform for large-scale electrophysiology is whether or not a particular data acquisition system is 'open' or 'closed': that is, whether or not the system's schematics and source code are available to end users. Open systems have a reputation for being difficult to acquire, poorly documented, and hard to maintain. With the arrival of more powerful and compact integrated circuits, rapid prototyping services, and web-based tools for collaborative development, these stereotypes must be reconsidered. We discuss some of the reasons why multichannel extracellular electrophysiology could benefit from open-source approaches and describe examples of successful community-driven tool development within this field. In order to promote the adoption of open-source hardware and to reduce the need for redundant development efforts, we advocate a move toward standardized interfaces that connect each element of the data processing pipeline. This will give researchers the flexibility to modify their tools when necessary, while allowing them to continue to benefit from the high-quality products and expertise provided by commercial vendors. PMID:25528614

  15. Neural ensemble communities: Open-source approaches to hardware for large-scale electrophysiology

    PubMed Central

    Siegle, Joshua H.; Hale, Gregory J.; Newman, Jonathan P.; Voigts, Jakob

    2014-01-01

    One often-overlooked factor when selecting a platform for large-scale electrophysiology is whether or not a particular data acquisition system is “open” or “closed”: that is, whether or not the system’s schematics and source code are available to end users. Open systems have a reputation for being difficult to acquire, poorly documented, and hard to maintain. With the arrival of more powerful and compact integrated circuits, rapid prototyping services, and web-based tools for collaborative development, these stereotypes must be reconsidered. We discuss some of the reasons why multichannel extracellular electrophysiology could benefit from open-source approaches and describe examples of successful community-driven tool development within this field. In order to promote the adoption of open-source hardware and to reduce the need for redundant development efforts, we advocate a move toward standardized interfaces that connect each element of the data processing pipeline. This will give researchers the flexibility to modify their tools when necessary, while allowing them to continue to benefit from the high-quality products and expertise provided by commercial vendors. PMID:25528614

  16. Electrophysiological Correlates of Rapid Auditory and Linguistic Processing in Adolescents with Specific Language Impairment

    PubMed Central

    Weber-Fox, Christine; Leonard, Laurence B.; Wray, Amanda Hampton; Tomblin, J. Bruce

    2010-01-01

    Brief tonal stimuli and spoken sentences were utilized to examine whether adolescents (aged 14;3-18;1) with specific language impairments (SLI) exhibit atypical neural activity for rapid auditory processing of non-linguistic stimuli and linguistic processing of verb-agreement and semantic constraints. Further, we examined whether the behavioral and electrophysiological indices for rapid auditory processing were correlated with those for linguistic processing. Fifteen adolescents with SLI and 15 adolescents with normal language met strict criteria for displaying consistent diagnoses from kindergarten through the eighth grade. The findings provide evidence that auditory processing for non-linguistic stimuli is atypical in a significant number of adolescents with SLI compared to peers with normal language and indicate that reduced efficiency in auditory processing in SLI is more vulnerable to rapid rates (200 ms ISI) of stimuli presentation (indexed by reduced accuracy, a tendency for longer RTs, reduced N100 over right anterior sites, and reduced amplitude P300). Many adolescents with SLI displayed reduced behavioral accuracy for detecting verb-agreement violations and semantic anomalies, along with less robust P600s elicited by verb-agreement violations. The results indicate that ERPs elicited by morphosyntactic aspects of language processing are atypical in many adolescents with SLI. Additionally, correlational analyses between behavioral and electrophysiological indices of processing non-linguistic stimuli and verb-agreement violations suggest that the integrity of neural functions for auditory processing may only account for a small proportion of the variance in morphosyntactic processing in some adolescents. PMID:20889197

  17. Simultaneous wireless electrophysiological and neurochemical monitoring

    NASA Astrophysics Data System (ADS)

    Murari, Kartikeya; Mollazadeh, Mohsen; Thakor, Nitish; Cauwenberghs, Gert

    2008-08-01

    Information processing and propagation in the central nervous system is mostly electrical in nature. At synapses, electrical signals cause the release of neurotransmitters like dopamine, glutamate etc., that are sensed by post-synaptic neurons resulting in signal propagation or inhibition. It can be very informative to monitor electrical and neurochemical signals simultaneously to understand the mechanisms underlying normal or abnormal brain function. We present an integrated system for the simultaneous wireless acquisition of neurophysiological and neurochemical activity. Applications of the system to neuroscience include monitoring EEG and glutamate in rat somatosensory cortex following global ischemia.

  18. Comparison of electrophysiological data from human-induced pluripotent stem cell-derived cardiomyocytes to functional preclinical safety assays.

    PubMed

    Harris, Kate; Aylott, Mike; Cui, Yi; Louttit, James B; McMahon, Nicholas C; Sridhar, Arun

    2013-08-01

    Human-induced pluripotent stem cell cardiomyocytes (hiPSC-CMs) are a potential source to develop assays for predictive electrophysiological safety screening. Published studies show that the relevant physiology and pharmacology exist but does not show the translation between stem cell cardiomyocyte assays and other preclinical safety screening assays, which is crucial for drug discovery and safety scientists and the regulators. Our studies are the first to show the pharmacology of ion channel blockade and compare them with existing functional cardiac electrophysiology studies. Ten compounds (a mixture of pure hERG [E-4031 and Cisapride], hERG and sodium [Flecainide, Mexiletine, Quinidine, and Terfenadine], calcium channel blockers [Nifedipine and Verapamil], and two proprietary compounds [GSK A and B]) were tested, and results from hiPSC-CMs studied on multielectrode arrays (MEA) were compared with other preclincial models and clinical drug concentrations and effects using integrated risk assessment plots. All ion channel blockers produced (1) functional effects on repolarization and depolarization around the IC25 and IC50 values and (2) excessive blockade of hERG and/or blockade of sodium current precipitated arrhythmias. Our MEA data show that hiPSC-CMs demonstrate relevant pharmacology and show excellent correlations to current functional cardiac electrophysiological studies. Based on these results, MEA assays using iPSC-CMs offer a reliable, cost effective, and surrogate to preclinical in vitro testing, in addition to the 3Rs (refine, reduce, and replace animals in research) benefit. PMID:23690542

  19. Contracting guidelines for internists.

    PubMed

    1984-09-01

    Government regulations, the introduction of new health care delivery methods, and the rising number of physicians joining the medical community have combined to increase the importance of the business aspect of medical practice. As a result, many physicians have documented their relationships with various third parties through contracts. As the incidence of contractual relationships between physicians and third parties has increased, so has concern regarding the legal ramifications of the contracting process. This guide is intended to explain the basic characteristics of contracts and to provide the individual physician with information regarding the contracting process. The guide is divided into three sections: key elements of a contract; types of contracts, including hospital/physician contracts, hospital/physician joint ventures, and group practice contracts; and negotiating the contract. Each section offers an explanation of the topic, which is followed by specific questions for the individual physician to investigate. These lists of questions are designed to provide a starting point for physician discussion of the philosophical, personal and practical areas to investigate before entering into a contract. PMID:10268633

  20. Breadboard Amplifier: Building and Using Simple Electrophysiology Equipment

    PubMed Central

    Crisp, Kevin M.; Lin, Hunter; Prosper, Issa

    2016-01-01

    Electrophysiology is a valuable skill for the neuroscientist, but the learning curve for students can be steep. Here we describe a very simple electromyography (EMG) amplifier that can be built from scratch by students with no electronics experience in about 30 minutes, making it ideal for incorporating into a laboratory activity. With few parts and no adjustments except the gain, students can begin physiology experiments quickly while having the satisfaction of having built the equipment themselves. Because the output of the circuit goes to a computer sound card, students can listen to electrophysiological activity as they see it on the computer screen, a feature many of our students greatly appreciated. Various applications are discussed, including dual channel recording, using streaming media platforms with remote lab partners and acquiring data in the field on a smart phone. Our students reported that they enjoyed being able to build a working device and using it to record from their own muscles. PMID:27385921

  1. Nanomaterial-Enabled Dry Electrodes for Electrophysiological Sensing: A Review

    NASA Astrophysics Data System (ADS)

    Yao, Shanshan; Zhu, Yong

    2016-04-01

    Long-term, continuous, and unsupervised tracking of physiological data is becoming increasingly attractive for health/wellness monitoring and ailment treatment. Nanomaterials have recently attracted extensive attention as building blocks for flexible/stretchable conductors and are thus promising candidates for electrophysiological electrodes. Here we provide a review on nanomaterial-enabled dry electrodes for electrophysiological sensing, focusing on electrocardiography (ECG). The dry electrodes can be classified into contact surface electrodes, contact-penetrating electrodes, and noncontact capacitive electrodes. Different types of electrodes including their corresponding equivalent electrode-skin interface models and the sources of the noise are first introduced, followed by a review on recent developments of dry ECG electrodes based on various nanomaterials, including metallic nanowires, metallic nanoparticles, carbon nanotubes, and graphene. Their fabrication processes and performances in terms of electrode-skin impedance, signal-to-noise ratio, resistance to motion artifacts, skin compatibility, and long-term stability are discussed.

  2. [Value of functional and electrophysiological studies in amblyopia].

    PubMed

    Korol, S; Fiore, C

    1976-04-01

    In a group of patients suffering from amblyopia, the authors confront the results after orthoptic treatment with data provided by functional and electrophysiological examination. In 37 patients the clinical diagnosis of functional amblyopia had been made, but in 8 of these cases complimentary functional and electrophysiological examinations showed organic perturbations. This explains the failure, in these cases, of the orthoptic treatment. In the remaining 29 patients, clinical forms of functional amblyopia were found. In this group, the authors studied 20 cases showing no improvement with treatment: in 15 out of the 20 the VERs were pathological. In the 9 remaining cases which have showed improvement the VER'S were never abnormal. VER study can be undertaken, without general anaesthesia, as from 3 to 4 years of age. The authors conclude that all clinical forms of amblyopia should undergo VER investigation: patients showing pathological changes should be excluded from orthoptic treatment, from which they have no possibility of deriving benefit. PMID:135545

  3. Windows software for cardiac electrophysiology studies and ablation monitoring.

    PubMed

    Vänttinen, H; Nousiainen, J; Mäkynen, P; Malmivuo, J

    2000-03-01

    A system for cardiac electrophysiology (EP) studies consisting of a Windows software package, a standard 120 MHz Pentium PC with a high-performance video card and a data acquisition card has been developed during this study. The system is capable of real time data acquisition and storage of 24 channels with simultaneous display of 1-16 arbitrarily chosen channels at a sampling rate of 500 Hz. It can be used clinically in electrophysiology studies and during catheter radio-frequency ablation treatment for monitoring the ablation and its effects. The built-in ablation monitoring capability enables combined EP study and ablation treatment, thus helping to reduce exposure times and the total time needed per patient. For clinical use the software includes versatile tools for data analysis and reduction. Our system has been developed in association with Department of Cardiology of Tampere University Hospital and has been in regular clinical use there. PMID:10710184

  4. Pants on fire: the electrophysiological signature of telling a lie.

    PubMed

    Pfister, Roland; Foerster, Anna; Kunde, Wilfried

    2014-01-01

    Even though electroencephalography has played a prominent role for lie detection via personally relevant information, the electrophysiological signature of active lying is still elusive. We addressed this signature with two experiments in which participants helped a virtual police officer to locate a knife. Crucially, before this response, they announced whether they would lie or tell the truth about the knife's location. This design allowed us to study the signature of lie-telling in the absence of rare and personally significant oddball stimuli that are typically used for lie detection via electrophysiological markers, especially the P300 component. Our results indicate that active lying attenuated P300 amplitudes as well as N200 amplitudes for such non-oddball stimuli. These results support accounts that stress the high cognitive demand of lie-telling, including the need to suppress the truthful response and to generate a lie. PMID:24972014

  5. A comparison of solver performance for complex gastric electrophysiology models.

    PubMed

    Sathar, Shameer; Cheng, Leo K; Trew, Mark L

    2015-08-01

    Computational techniques for solving systems of equations arising in gastric electrophysiology have not been studied for efficient solution process. We present a computationally challenging problem of simulating gastric electrophysiology in anatomically realistic stomach geometries with multiple intracellular and extracellular domains. The multiscale nature of the problem and mesh resolution required to capture geometric and functional features necessitates efficient solution methods if the problem is to be tractable. In this study, we investigated and compared several parallel preconditioners for the linear systems arising from tetrahedral discretisation of electrically isotropic and anisotropic problems, with and without stimuli. The results showed that the isotropic problem was computationally less challenging than the anisotropic problem and that the application of extracellular stimuli increased workload considerably. Preconditioning based on block Jacobi and algebraic multigrid solvers were found to have the best overall solution times and least iteration counts, respectively. The algebraic multigrid preconditioner would be expected to perform better on large problems. PMID:26736543

  6. Breadboard Amplifier: Building and Using Simple Electrophysiology Equipment.

    PubMed

    Crisp, Kevin M; Lin, Hunter; Prosper, Issa

    2016-01-01

    Electrophysiology is a valuable skill for the neuroscientist, but the learning curve for students can be steep. Here we describe a very simple electromyography (EMG) amplifier that can be built from scratch by students with no electronics experience in about 30 minutes, making it ideal for incorporating into a laboratory activity. With few parts and no adjustments except the gain, students can begin physiology experiments quickly while having the satisfaction of having built the equipment themselves. Because the output of the circuit goes to a computer sound card, students can listen to electrophysiological activity as they see it on the computer screen, a feature many of our students greatly appreciated. Various applications are discussed, including dual channel recording, using streaming media platforms with remote lab partners and acquiring data in the field on a smart phone. Our students reported that they enjoyed being able to build a working device and using it to record from their own muscles. PMID:27385921

  7. Space Motion Sickness and Stress Training Simulator using Electrophysiological Biofeedback

    NASA Astrophysics Data System (ADS)

    Gaudeau, C.; Golding, J. F.; Thevot, F.; Lucas, Y.; Bobola, P.; Thouvenot, J.

    2005-06-01

    An important problem in manned spaceflight is the nausea that typically appears during the first 3 days and then disappears after 5 days. Methods of detecting changes in electrophysiological signals are being studied in order to reduce susceptibility to space motion sickness through biofeedback training, and for the early detection of nausea during EVA. A simulator would allow subjects to control their body functions and to use biofeedback to control space motion sickness and stress.

  8. From Galvani to patch clamp: the development of electrophysiology.

    PubMed

    Verkhratsky, Alexei; Krishtal, O A; Petersen, Ole H

    2006-12-01

    The development of electrophysiology is traced from the early beginnings represented by the work of the Dutch microscopist, Jan Swammerdam, in the 17th century through the first notion of an aqueous transmembrane pore as a substrate of excitability made by Luigi Galvani in late 18th century to the invention late in the 20th century of the patch-clamp technique by Erwin Neher and Bert Sakmann. PMID:17072639

  9. The Simon effect in cognitive electrophysiology: A short review.

    PubMed

    Leuthold, Hartmut

    2011-02-01

    In the Simon task, stimuli are presented laterally and typically a non-spatial stimulus dimension demands a lateralized choice response. Responses are faster when the task-irrelevant stimulus location and the response location correspond than when they do not correspond. The present paper explores the impact of the Simon task on cognitive electrophysiological research as well as the insights gained from event-related brain potentials (ERPs) in the attempt to uncover the hidden mechanisms underlying the Simon effect. PMID:20828671

  10. Electrophysiological Imaging of Brain Activity and Connectivity – Challenges and Opportunities

    PubMed Central

    He, Bin; Yang, Lin; Wilke, Christopher; Yuan, Han

    2011-01-01

    Unlocking the dynamic inner workings of the brain continues to remain a grand challenge of the 21st century. To this end, functional neuroimaging modalities represent an outstanding approach to better understand the mechanisms of both normal and abnormal brain function. The ability to image brain function with ever increasing spatial and temporal resolution utilizing minimal or non-invasive procedures has made a significant leap over the past several decades. Further delineation of functional networks could lead to improved understanding of brain function in both normal as well as diseased states. This article reviews recent advancements and current challenges in dynamic functional neuroimaging techniques, including electrophysiological source imaging, multimodal neuroimaging integrating fMRI with EEG/MEG, and functional connectivity imaging. PMID:21478071

  11. High-density optrodes for multi-scale electrophysiology and optogenetic stimulation.

    PubMed

    Chamanzar, Maysamreza; Borysov, Mykhailo; Maharbiz, Michel M; Blanche, Timothy J

    2014-01-01

    We demonstrate the design and implementation of hybrid optical-electrical probes (`optrodes') for high resolution electrophysiology and optogenetic stimulation of neurons in multiple brain areas. Our 64-channel implantable optrodes are minimally invasive (50 μm × 20 μm) and span 1~2 mm. To minimize tethering forces on the brain tissue a monolithic high-density flexible cable (6 μm thin) connects the probe to a lightweight headstage (1.3 gr, 256 channel configuration) designed for awake, freely-behaving small animals. A polymer-based multi-channel photonic light delivery system is integrated on shank in a separate layer, providing local optogenetic stimulation of the neural population adjacent to the probe. The entire manufacturing process, including the nanofabrication of the optrodes, post-fabrication assembly, and surgical implantation procedures are designed to be scalable, high-yield, and high-throughput. PMID:25571567

  12. Using Extracellular Single-unit Electrophysiological Data as a Substrate for Investigative Laboratory Exercises.

    PubMed

    Cousens, Graham A; Muir, Gary M

    2006-01-01

    Desirable objectives for laboratory-based science courses include fostering skills in problem solving and reasoning, enhancing data fluency, and encouraging consideration of science as an integrative enterprise. An effective means of reaching these objectives is to structure learning experiences around interesting problems in our own research. In this article, we explore the idea of using extracellular single-unit electrophysiological data as a substrate for student investigatory exercises as a means of achieving many of these objectives. In the article, we provide an overview of extracellular single-unit recording techniques and discuss the organization of single-unit data files. In addition, we describe a multi-week module recently administered in an intermediate-level laboratory course and provide suggestions both for more limited exercises and for more advanced projects. Finally, we describe a companion website that provides to instructors considering implementing similar exercises access to a variety of resources, including software, sample data, and additional information. PMID:23493564

  13. A Wireless Optogenetic Headstage with Multichannel Electrophysiological Recording Capability.

    PubMed

    Gagnon-Turcotte, Gabriel; Kisomi, Alireza Avakh; Ameli, Reza; Camaro, Charles-Olivier Dufresne; LeChasseur, Yoan; Néron, Jean-Luc; Bareil, Paul Brule; Fortier, Paul; Bories, Cyril; de Koninck, Yves; Gosselin, Benoit

    2015-01-01

    We present a small and lightweight fully wireless optogenetic headstage capable of optical neural stimulation and electrophysiological recording. The headstage is suitable for conducting experiments with small transgenic rodents, and features two implantable fiber-coupled light-emitting diode (LED) and two electrophysiological recording channels. This system is powered by a small lithium-ion battery and is entirely built using low-cost commercial off-the-shelf components for better flexibility, reduced development time and lower cost. Light stimulation uses customizable stimulation patterns of varying frequency and duty cycle. The optical power that is sourced from the LED is delivered to target light-sensitive neurons using implantable optical fibers, which provide a measured optical power density of 70 mW/mm² at the tip. The headstage is using a novel foldable rigid-flex printed circuit board design, which results into a lightweight and compact device. Recording experiments performed in the cerebral cortex of transgenic ChR2 mice under anesthetized conditions show that the proposed headstage can trigger neuronal activity using optical stimulation, while recording microvolt amplitude electrophysiological signals. PMID:26371006

  14. Effects of Morphology Constraint on Electrophysiological Properties of Cortical Neurons

    PubMed Central

    Zhu, Geng; Du, Liping; Jin, Lei; Offenhäusser, Andreas

    2016-01-01

    There is growing interest in engineering nerve cells in vitro to control architecture and connectivity of cultured neuronal networks or to build neuronal networks with predictable computational function. Pattern technologies, such as micro-contact printing, have been developed to design ordered neuronal networks. However, electrophysiological characteristics of the single patterned neuron haven’t been reported. Here, micro-contact printing, using polyolefine polymer (POP) stamps with high resolution, was employed to grow cortical neurons in a designed structure. The results demonstrated that the morphology of patterned neurons was well constrained, and the number of dendrites was decreased to be about 2. Our electrophysiological results showed that alterations of dendritic morphology affected firing patterns of neurons and neural excitability. When stimulated by current, though both patterned and un-patterned neurons presented regular spiking, the dynamics and strength of the response were different. The un-patterned neurons exhibited a monotonically increasing firing frequency in response to injected current, while the patterned neurons first exhibited frequency increase and then a slow decrease. Our findings indicate that the decrease in dendritic complexity of cortical neurons will influence their electrophysiological characteristics and alter their information processing activity, which could be considered when designing neuronal circuitries. PMID:27052791

  15. Effects of Morphology Constraint on Electrophysiological Properties of Cortical Neurons

    NASA Astrophysics Data System (ADS)

    Zhu, Geng; Du, Liping; Jin, Lei; Offenhäusser, Andreas

    2016-04-01

    There is growing interest in engineering nerve cells in vitro to control architecture and connectivity of cultured neuronal networks or to build neuronal networks with predictable computational function. Pattern technologies, such as micro-contact printing, have been developed to design ordered neuronal networks. However, electrophysiological characteristics of the single patterned neuron haven’t been reported. Here, micro-contact printing, using polyolefine polymer (POP) stamps with high resolution, was employed to grow cortical neurons in a designed structure. The results demonstrated that the morphology of patterned neurons was well constrained, and the number of dendrites was decreased to be about 2. Our electrophysiological results showed that alterations of dendritic morphology affected firing patterns of neurons and neural excitability. When stimulated by current, though both patterned and un-patterned neurons presented regular spiking, the dynamics and strength of the response were different. The un-patterned neurons exhibited a monotonically increasing firing frequency in response to injected current, while the patterned neurons first exhibited frequency increase and then a slow decrease. Our findings indicate that the decrease in dendritic complexity of cortical neurons will influence their electrophysiological characteristics and alter their information processing activity, which could be considered when designing neuronal circuitries.

  16. Exploring the unknown: electrophysiological and behavioural measures of visuospatial learning.

    PubMed

    Quinlivan, Brendan; Butler, John S; Ridwan, Abdur Raquib; Beiser, Ines; Williams, Laura; McGovern, Eavan; O'Riordan, Sean; Hutchinson, Michael; Reilly, Richard B

    2016-05-01

    Visuospatial memory describes our ability to temporarily store and manipulate visual and spatial information and is employed for a wide variety of complex cognitive tasks. Here, a visuospatial learning task requiring fine motor control is employed to investigate visuospatial learning in a group of typically developing adults. Electrophysiological and behavioural data are collected during a target location task under two experimental conditions: Target Learning and Target Cued. Movement times (MTs) are employed as a behavioural metric of performance, while dynamic P3b amplitudes and power in the alpha band (approximately 10 Hz) are explored as electrophysiological metrics during visuospatial learning. Results demonstrate that task performance, as measured by MT, is highly correlated with P3b amplitude and alpha power at a consecutive trial level (trials 1-30). The current set of results, in conjunction with the existing literature, suggests that changes in P3b amplitude and alpha power could correspond to different aspects of the learning process. Here it is hypothesized that changes in P3b correspond to a diminishing inter-stimulus interval and reduced stimulus relevance, while the corresponding changes in alpha power represent an automation of response as habituation occurs in participants. The novel analysis presented in the current study demonstrates how gradual electrophysiological changes can be tracked during the visuospatial learning process under the current paradigm. PMID:26840918

  17. A Wireless Optogenetic Headstage with Multichannel Electrophysiological Recording Capability

    PubMed Central

    Gagnon-Turcotte, Gabriel; Avakh Kisomi, Alireza; Ameli, Reza; Dufresne Camaro, Charles-Olivier; LeChasseur, Yoan; Néron, Jean-Luc; Brule Bareil, Paul; Fortier, Paul; Bories, Cyril; de Koninck, Yves; Gosselin, Benoit

    2015-01-01

    We present a small and lightweight fully wireless optogenetic headstage capable of optical neural stimulation and electrophysiological recording. The headstage is suitable for conducting experiments with small transgenic rodents, and features two implantable fiber-coupled light-emitting diode (LED) and two electrophysiological recording channels. This system is powered by a small lithium-ion battery and is entirely built using low-cost commercial off-the-shelf components for better flexibility, reduced development time and lower cost. Light stimulation uses customizable stimulation patterns of varying frequency and duty cycle. The optical power that is sourced from the LED is delivered to target light-sensitive neurons using implantable optical fibers, which provide a measured optical power density of 70 mW/mm2 at the tip. The headstage is using a novel foldable rigid-flex printed circuit board design, which results into a lightweight and compact device. Recording experiments performed in the cerebral cortex of transgenic ChR2 mice under anesthetized conditions show that the proposed headstage can trigger neuronal activity using optical stimulation, while recording microvolt amplitude electrophysiological signals. PMID:26371006

  18. [Electrophysiological evaluation of pathophysiological and pharmacological characteristics of chronic pain].

    PubMed

    Tanabe, Mitsuo

    2014-01-01

    Recent studies have revealed considerable evidence for our understanding of the mechanisms underlying the development and maintenance of chronic pain including neuropathic and inflammatory pain. It is considered that plastic changes in the spinal dorsal horn contribute to the amplification of pain signaling. Moreover, persistent pain affects brain function and also the endogenous descending pain regulatory system. To characterize these pathophysiological changes and pharmacological properties in chronic pain conditions at the synaptic level, we have employed in vitro electrophysiology in slices of the spinal cord and supraspinal regions such as brainstem and hippocampus of adult mice and in vivo electrophysiology in anesthetized rats. In particular, we have successfully prepared spinal slices with an attached dorsal root, where A-fiber- or C-fiber-evoked monosynaptic excitatory postsynaptic currents or miniature excitatory postsynaptic currents were recorded from voltage-clamped dorsal horn neurons. In anesthetized rats, C-fiber-evoked field potentials were recorded from the spinal dorsal horn in response to electrical stimulation of the sciatic nerve fibers, and their long-term potentiation was elicited to mimic increased synaptic efficacy after peripheral nerve injury. Of interest is the finding that some drugs exerted the injury-specific effects on synaptic transmission, thus strongly suggesting the importance of pharmacological analysis at the synaptic level combined with electrophysiological techniques to obtain pathophysiological information and new insights into drug research in this field. PMID:24584022

  19. Effects of Morphology Constraint on Electrophysiological Properties of Cortical Neurons.

    PubMed

    Zhu, Geng; Du, Liping; Jin, Lei; Offenhäusser, Andreas

    2016-01-01

    There is growing interest in engineering nerve cells in vitro to control architecture and connectivity of cultured neuronal networks or to build neuronal networks with predictable computational function. Pattern technologies, such as micro-contact printing, have been developed to design ordered neuronal networks. However, electrophysiological characteristics of the single patterned neuron haven't been reported. Here, micro-contact printing, using polyolefine polymer (POP) stamps with high resolution, was employed to grow cortical neurons in a designed structure. The results demonstrated that the morphology of patterned neurons was well constrained, and the number of dendrites was decreased to be about 2. Our electrophysiological results showed that alterations of dendritic morphology affected firing patterns of neurons and neural excitability. When stimulated by current, though both patterned and un-patterned neurons presented regular spiking, the dynamics and strength of the response were different. The un-patterned neurons exhibited a monotonically increasing firing frequency in response to injected current, while the patterned neurons first exhibited frequency increase and then a slow decrease. Our findings indicate that the decrease in dendritic complexity of cortical neurons will influence their electrophysiological characteristics and alter their information processing activity, which could be considered when designing neuronal circuitries. PMID:27052791

  20. Electrophysiological evidence of early word learning.

    PubMed

    Junge, Caroline; Cutler, Anne; Hagoort, Peter

    2012-12-01

    Around their first birthday infants begin to talk, yet they comprehend words long before. This study investigated the event-related potentials (ERP) responses of nine-month-olds on basic level picture-word pairings. After a familiarization phase of six picture-word pairings per semantic category, comprehension for novel exemplars was tested in a picture-word matching paradigm. ERPs time-locked to pictures elicited a modulation of the negative central (Nc) component, associated with visual attention and recognition. It was attenuated by category repetition as well as by the type-token ratio of picture context. ERPs time-locked to words in the training phase became more negative with repetition (N300-600), but there was no influence of picture type-token ratio, suggesting that infants have identified the concept of each picture before a word was presented. Results from the test phase provided clear support that infants integrated word meanings with (novel) picture context. Here, infants showed different ERP responses for words that did or did not align with the picture context: a phonological mismatch (N200) and a semantic mismatch (N400). Together, results were informative of visual categorization, word recognition and word-to-world-mappings, all three crucial processes for vocabulary construction. PMID:23108241

  1. Mechanobiology of lymphatic contractions.

    PubMed

    Munn, Lance L

    2015-02-01

    The lymphatic system is responsible for controlling tissue fluid pressure by facilitating flow of lymph (i.e. the plasma and cells that enter the lymphatic system). Because lymph contains cells of the immune system, its transport is not only important for fluid homeostasis, but also immune function. Lymph drainage can occur via passive flow or active pumping, and much research has identified the key biochemical and mechanical factors that affect output. Although many studies and reviews have addressed how tissue properties and fluid mechanics (i.e. pressure gradients) affect lymph transport [1-3] there is less known about lymphatic mechanobiology. As opposed to passive mechanical properties, mechanobiology describes the active coupling of mechanical signals and biochemical pathways. Lymphatic vasomotion is the result of a fascinating system affected by mechanical forces exerted by the flowing lymph, including pressure-induced vessel stretch and flow-induced shear stresses. These forces can trigger or modulate biochemical pathways important for controlling the lymphatic contractions. Here, I review the current understanding of lymphatic vessel function, focusing on vessel mechanobiology, and summarize the prospects for a comprehensive understanding that integrates the mechanical and biomechanical control mechanisms in the lymphatic system. PMID:25636584

  2. Electrogenesis in the lower Metazoa and implications for neuronal integration.

    PubMed

    Meech, Robert W

    2015-02-15

    Electrogenic communication appears to have evolved independently in a variety of animal and plant lineages. Considered here are metazoan cells as disparate as the loose three-dimensional parenchyma of glass sponges, the two-dimensional epithelial sheets of hydrozoan jellyfish and the egg cell membranes of the ctenophore Beroe ovata, all of which are capable of generating electrical impulses. Neuronal electrogenesis may have evolved independently in ctenophores and cnidarians but the dearth of electrophysiological data relating to ctenophore nerves means that our attention is focused on the Cnidaria, whose nervous systems have been the subject of extensive study. The aim here is to show how their active and passive neuronal properties interact to give integrated behaviour. Neuronal electrogenesis, goes beyond simply relaying 'states of excitement' and utilizes the equivalent of a set of basic electrical 'apps' to integrate incoming sensory information with internally generated pacemaker activity. A small number of membrane-based processes make up these analogue applications. Passive components include the decremental spread of current determined by cellular anatomy; active components include ion channels specified by their selectivity and voltage dependence. A recurring theme is the role of inactivating potassium channels in regulating performance. Although different aspects of cnidarian behaviour are controlled by separate neuronal systems, integrated responses and coordinated movements depend on interactions between them. Integrative interactions discussed here include those between feeding and swimming, between tentacle contraction and swimming and between slow and fast swimming in the hydrozoan jellyfish Aglantha digitale. PMID:25696817

  3. Electrogenesis in the lower Metazoa and implications for neuronal integration

    PubMed Central

    Meech, Robert W.

    2015-01-01

    Electrogenic communication appears to have evolved independently in a variety of animal and plant lineages. Considered here are metazoan cells as disparate as the loose three-dimensional parenchyma of glass sponges, the two-dimensional epithelial sheets of hydrozoan jellyfish and the egg cell membranes of the ctenophore Beroe ovata, all of which are capable of generating electrical impulses. Neuronal electrogenesis may have evolved independently in ctenophores and cnidarians but the dearth of electrophysiological data relating to ctenophore nerves means that our attention is focused on the Cnidaria, whose nervous systems have been the subject of extensive study. The aim here is to show how their active and passive neuronal properties interact to give integrated behaviour. Neuronal electrogenesis, goes beyond simply relaying ‘states of excitement’ and utilizes the equivalent of a set of basic electrical ‘apps’ to integrate incoming sensory information with internally generated pacemaker activity. A small number of membrane-based processes make up these analogue applications. Passive components include the decremental spread of current determined by cellular anatomy; active components include ion channels specified by their selectivity and voltage dependence. A recurring theme is the role of inactivating potassium channels in regulating performance. Although different aspects of cnidarian behaviour are controlled by separate neuronal systems, integrated responses and coordinated movements depend on interactions between them. Integrative interactions discussed here include those between feeding and swimming, between tentacle contraction and swimming and between slow and fast swimming in the hydrozoan jellyfish Aglantha digitale. PMID:25696817

  4. Alfaxalone Anaesthesia Facilitates Electrophysiological Recordings of Nociceptive Withdrawal Reflexes in Dogs (Canis familiaris).

    PubMed

    Hunt, James; Murrell, Jo; Knazovicky, David; Harris, John; Kelly, Sara; Knowles, Toby G; Lascelles, B Duncan X

    2016-01-01

    Naturally occurring canine osteoarthritis represents a welfare issue for affected dogs (Canis familiaris), but is also considered very similar to human osteoarthritis and has therefore been proposed as a model of disease in humans. Central sensitisation is recognized in human osteoarthritis sufferers but identification in dogs is challenging. Electromyographic measurement of responses to nociceptive stimulation represents a potential means of investigating alterations in central nociceptive processing, and has been evaluated in conscious experimental dogs, but is likely to be aversive. Development of a suitable anaesthetic protocol in experimental dogs, which facilitated electrophysiological nociceptive withdrawal reflex assessment, may increase the acceptability of using the technique in owned dogs with naturally occurring osteoarthritis. Seven purpose bred male hound dogs underwent electromyographic recording sessions in each of three states: acepromazine sedation, alfaxalone sedation, and alfaxalone anaesthesia. Electromyographic responses to escalating mechanical and electrical, and repeated electrical, stimuli were recorded. Subsequently the integral of both early and late rectified responses was calculated. Natural logarithms of the integral values were analysed within and between the three states using multi level modeling. Alfaxalone increased nociceptive thresholds and decreased the magnitude of recorded responses, but characteristics of increasing responses with increasing stimulus magnitude were preserved. Behavioural signs of anxiety were noted in two out of seven dogs during recordings in the acepromazine sedated state. There were few significant differences in response magnitude or nociceptive threshold between the two alfaxalone states. Following acepromazine premedication, induction of anaesthesia with 1-2 mg kg-1 alfaxalone, followed by a continuous rate infusion in the range 0.075-0.1 mg kg-1 min-1 produced suitable conditions to enable assessment

  5. Alfaxalone Anaesthesia Facilitates Electrophysiological Recordings of Nociceptive Withdrawal Reflexes in Dogs (Canis familiaris)

    PubMed Central

    Hunt, James; Murrell, Jo; Knazovicky, David; Harris, John; Kelly, Sara; Knowles, Toby G.; Lascelles, B. Duncan X.

    2016-01-01

    Naturally occurring canine osteoarthritis represents a welfare issue for affected dogs (Canis familiaris), but is also considered very similar to human osteoarthritis and has therefore been proposed as a model of disease in humans. Central sensitisation is recognized in human osteoarthritis sufferers but identification in dogs is challenging. Electromyographic measurement of responses to nociceptive stimulation represents a potential means of investigating alterations in central nociceptive processing, and has been evaluated in conscious experimental dogs, but is likely to be aversive. Development of a suitable anaesthetic protocol in experimental dogs, which facilitated electrophysiological nociceptive withdrawal reflex assessment, may increase the acceptability of using the technique in owned dogs with naturally occurring osteoarthritis. Seven purpose bred male hound dogs underwent electromyographic recording sessions in each of three states: acepromazine sedation, alfaxalone sedation, and alfaxalone anaesthesia. Electromyographic responses to escalating mechanical and electrical, and repeated electrical, stimuli were recorded. Subsequently the integral of both early and late rectified responses was calculated. Natural logarithms of the integral values were analysed within and between the three states using multi level modeling. Alfaxalone increased nociceptive thresholds and decreased the magnitude of recorded responses, but characteristics of increasing responses with increasing stimulus magnitude were preserved. Behavioural signs of anxiety were noted in two out of seven dogs during recordings in the acepromazine sedated state. There were few significant differences in response magnitude or nociceptive threshold between the two alfaxalone states. Following acepromazine premedication, induction of anaesthesia with 1–2 mg kg-1 alfaxalone, followed by a continuous rate infusion in the range 0.075–0.1 mg kg-1 min-1 produced suitable conditions to enable

  6. Stac3 is a component of the excitation-contraction coupling machinery and mutated in Native American myopathy

    PubMed Central

    Horstick, Eric J.; Linsley, Jeremy W.; Dowling, James J.; Hauser, Michael A.; McDonald, Kristin K.; Ashley-Koch, Allison; Saint-Amant, Louis; Satish, Akhila; Cui, Wilson W.; Zhou, Weibin; Sprague, Shawn M.; Stamm, Demetra S.; Powell, Cynthia M.; Speer, Marcy C.; Franzini-Armstrong, Clara; Hirata, Hiromi; Kuwada, John Y.

    2013-01-01

    Excitation-contraction coupling, the process that regulates contractions by skeletal muscles, transduces changes in membrane voltage by activating release of Ca2+ from internal stores to initiate muscle contraction. Defects in EC coupling are associated with muscle diseases. Here we identify Stac3 as a novel component of the EC coupling machinery. Using a zebrafish genetic screen, we generate a locomotor mutation that is mapped to stac3. We provide electrophysiological, Ca2+ imaging, immunocytochemical and biochemical evidence that Stac3 participates in excitation-contraction coupling in muscles. Furthermore, we reveal that a mutation in human STAC3 as the genetic basis of the debilitating Native American myopathy (NAM). Analysis of NAM stac3 in zebrafish shows that the NAM mutation decreases excitation-contraction coupling. These findings enhance our understanding of both excitation-contraction coupling and the pathology of myopathies. PMID:23736855

  7. Electrophysiology of skilled performances in children.

    PubMed

    Chiarenza, G A

    1986-04-01

    Skilled performance is a result of appropriate integration of sensorimotor, cognitive and motivational functions. When Piaget was asked about the nature of reality and our knowledge of it, he answered: "I know an object only when I can act on it; before this action I cannot say anything about it". It has been proposed that motor actions are the source from which mental operations emerge. The intellectual growth of a child goes through stages during which actions, perceptions and ability for concrete or abstract thought hold in turn a predominant role. On the grounds of this theoretical framework it could be argued that neuropsychophysiological investigations of skilled performance in children which incorporate the study of performance-related brain electrical activity could contribute unique information with theoretical and clinical implications. A pattern of slow and phasic brain electrical activity is consistently associated with the execution of skilled ballistic tasks. The slow potentials of the preparatory period (Bereitschfts Potential-BP) are of low amplitude in low demand tasks and in young children. The potentials closely associated with the execution of the act and reflecting sensory feedback activity (Motor Cortex Potential-MCP) are constantly present in children of all ages. The potential associated with knowledge of results (Skilled Performance Positivity-SPP) is only present if task relevant exteroceptive information is expected and occurs. The SPP is independent of the action itself and of the existence of non-informative exteroceptive stimulation. The SPP is absent in unskilled tasks and in young children. The motor performance related with the execution of the motor act improves with increasing age.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3759404

  8. [Negative symptoms of schizophrenia: from electrophysiology to electrotherapy].

    PubMed

    Micoulaud Franchi, J-A; Quiles, C; Belzeaux, R; Adida, M; Azorin, J-M

    2015-12-01

    The aim of this review of the literature is to summarize the state of the knowledge concerning the relationship between negative symptoms in schizophrenia, electrophysiology and electrotherapy. The scientific literature search of international articles was performed during August and September 2015 using the PubMed electronic database. We used the following MeSH terms: "Negative symptoms", "Schizophrenia", "Electrophysiology", "Neurophysiology", "EEG power", "Alpha rhythm", "Transcranial magnetic stimulation", "Transcranial direct current stimulation", "Electroconvulsive therapy", "Neurofeedback", "Vagus Nerve Stimulation", "Deep Brain Stimulation", and "State dependent". Negative symptoms in schizophrenia are associated with altered activity in prefrontal cortex in functional neuroimaging studies. This is in line with electrophysiological measurements that found a change in EEG spectral power in the alpha frequency band over prefrontal brain regions. The notion of functional hypofrontality has led to hypotheses that electrotherapy applied to the prefrontal cortex may be an effective treatment of negative symptoms in schizophrenia. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) were used to increase cortical activity in schizophrenia and achieve a clinical effect on negative symptoms. Three meta-analyses confirmed, with a moderate effect size, that rTMS is an effective treatment option for negative symptoms in schizophrenia. The two subsequently published prospective multicenter studies, however, found opposite results from each other. Two randomized controlled studies suggested that tDCS is an effective treatment option for negative symptoms. There is no study on the efficacy of neurofeedback, vagal nerve stimulation or deep brain stimulation on negative symptoms in schizophrenia. Additional studies are needed to confirm the efficacy of rTMS and tDCS on negative symptoms in schizophrenia. Influencing factors

  9. 48 CFR 235.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Contracting methods and contract type. 235.006 Section 235.006 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.006 Contracting methods and...

  10. 48 CFR 235.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Contracting methods and contract type. 235.006 Section 235.006 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.006 Contracting methods and...

  11. Contract Training for Industry.

    ERIC Educational Resources Information Center

    Averill, Donald F.

    1983-01-01

    Describes contract training whereby industries arrange with community colleges, technical institutes, and vocational schools to prepare employees for specific job assignments. Indicates that industrial training performed under contract with public institutions should be encouraged in favor of expansion of training that industry performs for…

  12. Performance Contracting Overview.

    ERIC Educational Resources Information Center

    Wohlferd, Gerald H.

    Conclusions reached after three years of performance contracting experience and materials with which to judge the validity of the conclusions are presented in this overview of performance contracting. The conclusions are: (1) commercial firms are no better at teaching children than are public schools; (2) commercial firms expend as much or more…

  13. Contract Teachers in India

    ERIC Educational Resources Information Center

    Goyal, Sangeeta; Pandey, Priyanka

    2013-01-01

    In this paper, we use non-experimental data from government schools in Uttar Pradesh and Madhya Pradesh, two of the largest Indian states, to present average school outcomes by contract status of teachers. We find that contract teachers are associated with higher effort than civil service teachers with permanent tenures, before as well as after…

  14. Paramyotonia congenita. A clinical, electrophysiological and histological study of 12 patients.

    PubMed

    Wegmüller, E; Ludin, H P; Mumenthaler, M

    1979-01-01

    The present paper describes the clinical, electrophysiological and histological findings made in 12 patients belonging to 2 genealogical lineages in Switzerland, suffering from paramyotonia congenita. This is the first report of this disease in Switzerland. The myopathy, transmitted by autosomal dominant inheritance, is characterized by a typical past medical history and by the persistent contraction of the muscles of the face, arms and legs provoked by exposure to cold. Also of diagnostic importance are the myotonic reactions inducible at room temperature, such as percussion myotonia, active myotonia and paradoxical myotonia. During paramyotonic episodes provoked by exposure of the subjects in a refrigeration chamber, serum potassium concentrations remained within normal limits. Potassium loading producing serum levels above 6 mEq/1 in 2 patients gave rise to stiffness and weakness of the arms and legs, but no signs of paralysis. Induced hypokalemia in 3 cases caused no paramyotonic symptoms. Electromyographic recordings in 5 patients showed myotonic discharges, which disappeared upon cooling of the limb, giving way to progressive muscular stiffness. Histological, histochemical and electronmicroscopical examination of the muscle tissue revealed only diagnostically unspecific myopathological changes. PMID:90134

  15. Electrophysiological properties of laryngeal motoneurones in rats submitted to chronic intermittent hypoxia

    PubMed Central

    Moraes, Davi J A; Machado, Benedito H

    2015-01-01

    To keep an appropriate airflow to and from the lungs under physiological conditions a precise neural co-ordination of the upper airway resistance by laryngeal motoneurones in the nucleus ambiguus is essential. Chronic intermittent hypoxia (CIH), an important component of obstructive sleep apnoea, may alter these fine mechanisms. Here, using nerve and whole cell patch clamp recordings in in situ preparations of rats we investigated the effects of CIH on the respiratory control of the upper airway resistance, on the electrophysiological properties of laryngeal motoneurones in the nucleus ambiguus, and the role of carotid body (CB) afferents to the brainstem on the underlying mechanisms of these effects. CIH rats exhibited longer pre-inspiratory and lower post-inspiratory superior laryngeal nerve activities than control rats. These changes produced exaggerated glottal abduction (before inspiration) and decreased glottal adduction during post-inspiration, indicating a reduction of upper airway resistance during these respiratory phases after CIH. CB denervation abolished these changes produced by CIH. Regarding choline acetyltransferase positive-laryngeal motoneurones, CIH increased the firing frequency of inspiratory and decreased the firing frequency of post-inspiratory laryngeal motoneurones, without changes in their intrinsic electrophysiological properties. These data show that the effects of CIH on the upper airway resistance and laryngeal motoneurones activities are driven by the integrity of CB, which afferents induce changes in the central respiratory generators in the brainstem. These neural changes in the respiratory network seem to be an adaptive process required for an appropriated pulmonary ventilation and control of upper airway resistance under intermittent episodes of hypoxia. Key points The respiratory control of the glottis by laryngeal motoneurones is characterized by inspiratory abduction and post-inspiratory adduction causing decreases and

  16. Working Papers on Contract Education.

    ERIC Educational Resources Information Center

    Mullen, Robert; And Others

    Included in this package are: a copy of a learning contract between two students; an abstract fulfilling part of the contract objectives; and six papers on the topic of contract education. The goal of the learning contract was to edit and prepare for publication "Working Papers on Contract Education". The credential awarded for satisfactory…

  17. 48 CFR 35.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 35.006 Contracting methods and... projects when the objectives of the research are well defined and there is sufficient confidence in...

  18. Fibroblast KATP currents modulate myocyte electrophysiology in infarcted hearts.

    PubMed

    Benamer, Najate; Vasquez, Carolina; Mahoney, Vanessa M; Steinhardt, Maximilian J; Coetzee, William A; Morley, Gregory E

    2013-05-01

    Cardiac metabolism remains altered for an extended period of time after myocardial infarction. Studies have shown fibroblasts from normal hearts express KATP channels in culture. It is unknown whether fibroblasts from infarcted hearts express KATP channels and whether these channels contribute to scar and border zone electrophysiology. KATP channel subunit expression levels were determined in fibroblasts isolated from normal hearts (Fb), and scar (sMI-Fb) and remote (rMI-Fb) regions of left anterior descending coronary artery (LAD) ligated rat hearts. Whole cell KATP current density was determined with patch clamp. Action potential duration (APD) was measured with optical mapping in myocyte-only cultures and heterocellular cultures with fibroblasts with and without 100 μmol/l pinacidil. Whole heart optical mapping was used to assess KATP channel activity following LAD ligation. Pinacidil activated a potassium current (35.4 ± 7.5 pA/pF at 50 mV) in sMI-Fb that was inhibited with 10 μmol/l glibenclamide. Kir6.2 and SUR2 transcript levels were elevated in sMI-Fb. Treatment with Kir6.2 short interfering RNA decreased KATP currents (87%) in sMI-Fb. Treatment with pinacidil decreased APD (26%) in co-cultures with sMI-Fb. APD values were prolonged in LAD ligated hearts after perfusion with glibenclamide. KATP channels are present in fibroblasts from the scar and border zones of infarcted hearts. Activation of fibroblast KATP channels could modulate the electrophysiological substrate beyond the acute ischemic event. Targeting fibroblast KATP channels could represent a novel therapeutic approach to modify border zone electrophysiology after cardiac injury. PMID:23436329

  19. National Registry on Cardiac Electrophysiology 2007 and 2008.

    PubMed

    da Silva, Manuel Nogueira; Bonhorst, Daniel; de Sousa, João

    2009-11-01

    Clinical electrophysiology remains one of the most dynamic areas of cardiology, with continuing developments in equipping centers with more modern mapping and navigation systems. This has enabled an increase in the number and variety of interventions, resulting in significant improvements in results of therapeutic ablation of arrhythmias and prevention of sudden cardiac death. In this phase of transition towards implementation of a computerized national registry with nationwide data transmitted via the internet, publication of the registry in its previous form, although requiring more work, still seems justified, in order to appraise and disseminate qualitative and quantitative developments in this activity and enable comparisons with what is being done internationally, assess the centers' training capacity and inform national and European health authorities of the activities and real needs in this sector. The authors analyze the number and type of procedures performed during 2007 and 2008 based on a survey sent to centers performing diagnostic and interventional electrophysiology (16 centers in 2007 and 2008) and/or implanting cardioverter-defibrillators (ICDs) (19 centers in 2007 and 21 in 2008). Compared to 2006, one more center began interventional electrophysiology in 2007 and two centers began implanting ICDs in 2008. In the years under review, 2060 electrophysiological studies were performed in 2007 and 2007 were performed in 2008, of which 74 and 79.5% respectively were followed by therapeutic ablation, making totals of 1523 and 1596 ablations (increases of 10.7 and 4.6% from previous years). Atrioventricular nodal reentrant tachycardia was the main indication for ablation (28.4 and 28.7%), followed by accessory pathways (26.8 and 25.4%), atrial flutter (20.8 and 19.7%), atrial fibrillation (13.9 and 14.6%), ventricular tachycardia (4.7 and 5.1%), atrial tachycardia (2.8 and 2.6%) and atrioventricular junction ablation (2.7 and 3.9%). Regarding ICDs, a

  20. Electrophysiological studies of malaria parasite-infected erythrocytes: Current status

    PubMed Central

    Staines, Henry M.; Alkhalil, Abdulnaser; Allen, Richard J.; De Jonge, Hugo R.; Derbyshire, Elvira; Egée, Stéphane; Ginsburg, Hagai; Hill, David A.; Huber, Stephan M.; Kirk, Kiaran; Lang, Florian; Lisk, Godfrey; Oteng, Eugene; Pillai, Ajay D.; Rayavara, Kempaiah; Rouhani, Sherin; Saliba, Kevin J.; Shen, Crystal; Solomon, Tsione; Thomas, Serge L. Y.; Verloo, Patrick; Desai, Sanjay A.

    2009-01-01

    The altered permeability characteristics of erythrocytes infected with malaria parasites have been a source of interest for over 30 years. Recent electrophysiological studies have provided strong evidence that these changes reflect transmembrane transport through ion channels in the host erythrocyte plasma membrane. However, conflicting results and differing interpretations of the data have led to confusion in this field. In an effort to unravel these issues, the groups involved recently came together for a week of discussion and experimentation. In this article, the various models for altered transport are reviewed, together with the areas of consensus in the field and those that require a better understanding. PMID:17292372

  1. 76 FR 81807 - Operational Contract Support

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-29

    ... of a formally designated group, joint, or Military Department deployment center. (13) Support the... groups. (15) Integrate OCS into mission rehearsals and training exercises. (16) When contracts are being... Workforce Mix.'' Sec. 158.4 Policy. It is DoD policy that: (a) OCS actions (e.g., planning,...

  2. The Case for Performance Contracting.

    ERIC Educational Resources Information Center

    Miller, Sutherland; Wilson, Nancy

    1981-01-01

    Discussed the State of Colorado's introduction of performance contracting into its relationships with community mental health centers. Describes the nature of the contract and its implementation. Particular emphasis is placed on the implications of the contract for program evaluation. (Author)

  3. Mechanics of Vorticella contraction.

    PubMed

    Misra, Gaurav; Dickinson, Richard B; Ladd, Anthony J C

    2010-06-16

    Vorticella convallaria is one of a class of fast-moving organisms that can traverse its body size in less than a millisecond by rapidly coiling a slender stalk anchoring it to a nearby surface. The stalk houses a fiber called the spasmoneme, which winds helically within the stalk and rapidly contracts in response to calcium signaling. We have developed a coupled mechanical-chemical model of the coiling process, accounting for the coiling of the elastic stalk and the binding of calcium to the protein spasmin. Simulations of the model describe the contraction and recovery processes quantitatively. The stalk-spasmoneme system is shown to satisfy geometric constraints, which explains why the cell body sometimes rotates during contraction. The shape of the collapsing and recovering stalk bounds its effective bending stiffness. Simulations suggest that recovery from the contracted state is driven by the stalk at a rate controlled by dissociation of calcium from spasmin. PMID:20550905

  4. Electrophysiological fingerprints of OFF bipolar cells in rat retina.

    PubMed

    Vielma, Alex H; Schmachtenberg, Oliver

    2016-01-01

    Retinal bipolar cells (BCs) divide photoreceptor output into different channels for the parallel extraction of temporal and chromatic stimulus properties. In rodents, five types of OFF BCs have been differentiated, based on morphological and functional criteria, but their electrophysiological characterization remains incomplete. This study analyzed OFF BCs with the patch clamp technique in acute slices of rat retina. Their specific voltage-dependent currents and glutamate responses are shown to represent individual fingerprints which define the signal processing and filtering properties of each cell type and allow their unequivocal identification. Two additions to the rat BC repertoire are presented: OFF BC-2', a variation of BC-2 with wider axonal arbours and prominent Na(+) currents, is described for the first time in rodents, and OFF BC-3b, previously identified in mouse, is electrophysiologically characterized in rat. Moreover, the glutamate responses of rat OFF BCs are shown to be differentially sensitive to AMPA- and kainate-receptor blockers and to modulation by nitric oxide (NO) through a cGMP-dependent mechanism. These results contribute to our understanding of the diversity and function of bipolar cells in mammals. PMID:27457753

  5. Cardiac electrophysiology numerical models using symmetric multiprocessing (SMP).

    PubMed

    Petsios, Stefanos Konstantinos D; Fotiadis, Dimitrios I

    2009-01-01

    Multi-dimensional electrophysiological models have been introduced to investigate electrical propagation in tissue level, based on cell-dynamics models. The models include a set of non-linear differential equations which describe the dynamics of cell and tissue excitation. However, as models evolve, it is inevitable that proper and powerful tools need to be introduced in order to reproduce the detailed and thus computationally intensive simulations. To build such tools, several computational methodologies need to be adopted regarding efficiency and reliability. On the other hand improvements apply to the hardware too. State of the art computers, even personal computers, tend to make use of multiple core Central Processing Units. Unfortunately the aforementioned methodologies follow sequential logic, resulting to low efficiency of the working platform. In this work we present the performance bottleneck in symmetric multiprocessing (SMP) for simulations of propagation phenomena in cardiac tissue electrophysiological models. We demonstrate the scalability and efficacy of the different methodologies used in the discretisation scheme and message passing in SMP. PMID:19965052

  6. Investigating the electrophysiological basis of resting state networks using magnetoencephalography

    PubMed Central

    Brookes, Matthew J.; Woolrich, Mark; Luckhoo, Henry; Price, Darren; Hale, Joanne R.; Stephenson, Mary C.; Barnes, Gareth R.; Smith, Stephen M.; Morris, Peter G.

    2011-01-01

    In recent years the study of resting state brain networks (RSNs) has become an important area of neuroimaging. The majority of studies have used functional magnetic resonance imaging (fMRI) to measure temporal correlation between blood-oxygenation-level–dependent (BOLD) signals from different brain areas. However, BOLD is an indirect measure related to hemodynamics, and the electrophysiological basis of connectivity between spatially separate network nodes cannot be comprehensively assessed using this technique. In this paper we describe a means to characterize resting state brain networks independently using magnetoencephalography (MEG), a neuroimaging modality that bypasses the hemodynamic response and measures the magnetic fields associated with electrophysiological brain activity. The MEG data are analyzed using a unique combination of beamformer spatial filtering and independent component analysis (ICA) and require no prior assumptions about the spatial locations or patterns of the networks. This method results in RSNs with significant similarity in their spatial structure compared with RSNs derived independently using fMRI. This outcome confirms the neural basis of hemodynamic networks and demonstrates the potential of MEG as a tool for understanding the mechanisms that underlie RSNs and the nature of connectivity that binds network nodes. PMID:21930901

  7. Electrophysiological fingerprints of OFF bipolar cells in rat retina

    PubMed Central

    Vielma, Alex H.; Schmachtenberg, Oliver

    2016-01-01

    Retinal bipolar cells (BCs) divide photoreceptor output into different channels for the parallel extraction of temporal and chromatic stimulus properties. In rodents, five types of OFF BCs have been differentiated, based on morphological and functional criteria, but their electrophysiological characterization remains incomplete. This study analyzed OFF BCs with the patch clamp technique in acute slices of rat retina. Their specific voltage-dependent currents and glutamate responses are shown to represent individual fingerprints which define the signal processing and filtering properties of each cell type and allow their unequivocal identification. Two additions to the rat BC repertoire are presented: OFF BC-2′, a variation of BC-2 with wider axonal arbours and prominent Na+ currents, is described for the first time in rodents, and OFF BC-3b, previously identified in mouse, is electrophysiologically characterized in rat. Moreover, the glutamate responses of rat OFF BCs are shown to be differentially sensitive to AMPA- and kainate-receptor blockers and to modulation by nitric oxide (NO) through a cGMP-dependent mechanism. These results contribute to our understanding of the diversity and function of bipolar cells in mammals. PMID:27457753

  8. Electrophysiological mechanisms of the SI SII SIII electrocardiographic morphology

    SciTech Connect

    Bayes de Luna, A.; Carrio, I.; Subirana, M.T.; Torner, P.; Cosin, J.; Sagues, F.; Guindo, J.

    1987-01-01

    We studied three groups of individuals by means of spatial-velocity electrocardiograms and thallium-201 myocardial imaging to figure out the electrophysiological explanation of the SI SII SIII electrocardiographic morphology. We studied twelve healthy individuals without SI SII SIII, seven healthy individuals with SI SII SIII and fifteen patients with chronic obstructive pulmonary disease with SI SII SIII. The average values of the QRS-E and QRS-F intervals were higher in the second and third groups than in the first. One patient of the second group and thirteen of the third showed right ventricular enlargement. The slowing down of the right ventricular conduction explained the SI SII SIII morphology in normal individuals in more than half the cases. In patients with chronic obstructive pulmonary disease with SI SII SIII the conduction delay plays an important part in the electrogenesis of the right ventricular enlargement electrocardiographic morphology. We think that these observations can give further data about the electrophysiologic mechanism of the SI SII SIII morphology.

  9. Electrophysiology of Single and Aggregate Cx43 Hemichannels

    PubMed Central

    Brokamp, Cole; Todd, Jacob; Montemagno, Carlo; Wendell, David

    2012-01-01

    Connexin43 (Cx43) is the most ubiquitous gap junction protein in the human body and is essential for cell-to-cell communication in a variety of organs and organ systems. As a result, Cx43 is responsible for mediating both electrical and chemical signals, passing dissolved solutes and small signaling molecules between cells in a coordinated fashion. Here, we explore the electrophysiological properties of hemichannels formed from Cx43 and Cx43 fused to eGFP (Cx43eGFP) and their interactions in a planar lipid membrane (BLM). Unlike in vivo patch clamp experiments, Cx43 was purified and isolated from other membrane constituents allowing elucidation of individual protein responses to various electrical and chemical stimuli. Using this system, we examined hemichannel electrophysiology and the roles of several well-known gap junction blockers, namely: lanthanum, heptanol, carbenoxalone and lindane. We also observed a critical number of hemichannels required for an accelerated conductance increase, an emergent electrical signature indicative of plaque formation. PMID:23112846

  10. Analysis of electrophysiological properties and responses of neutrophils

    PubMed Central

    Morgan, Deri; DeCoursey, Thomas E.

    2014-01-01

    Summary The past decade has seen increasing use of the patch clamp technique on neutrophils and eosinophils. The main goal of these electrophysiological studies has been to elucidate the mechanisms underlying the phagocyte respiratory burst. NADPH oxidase activity, which defines the respiratory burst in granulocytes, is electrogenic because electrons from NADPH are transported across the cell membrane, where they reduce oxygen to form superoxide anion (O2−). This passage of electrons comprises an electrical current that would rapidly depolarize the membrane if the charge movement were not balanced by proton efflux. The patch clamp technique enables simultaneous recording of NADPH oxidase-generated electron current and H+ flux through the closely related H+ channel. Increasing evidence suggests that other ion channels may play crucial roles in degranulation, phagocytosis, and chemotaxis, highlighting the importance of electrophysiological studies to advance knowledge of granulocyte function. Several configurations of the patch clamp technique exist. Each has advantages and limitations that are discussed here. Meaningful measurements of ion channels cannot be achieved without an understanding of their fundamental properties. We describe the types of measurements that are necessary to characterize a particular ion channel. PMID:24504950

  11. Simultaneous Electrophysiological Recording and Calcium Imaging of Suprachiasmatic Nucleus Neurons

    PubMed Central

    Irwin, Robert P.; Allen, Charles N.

    2013-01-01

    Simultaneous electrophysiological and fluorescent imaging recording methods were used to study the role of changes of membrane potential or current in regulating the intracellular calcium concentration. Changing environmental conditions, such as the light-dark cycle, can modify neuronal and neural network activity and the expression of a family of circadian clock genes within the suprachiasmatic nucleus (SCN), the location of the master circadian clock in the mammalian brain. Excitatory synaptic transmission leads to an increase in the postsynaptic Ca2+ concentration that is believed to activate the signaling pathways that shifts the rhythmic expression of circadian clock genes. Hypothalamic slices containing the SCN were patch clamped using microelectrodes filled with an internal solution containing the calcium indicator bis-fura-2. After a seal was formed between the microelectrode and the SCN neuronal membrane, the membrane was ruptured using gentle suction and the calcium probe diffused into the neuron filling both the soma and dendrites. Quantitative ratiometric measurements of the intracellular calcium concentration were recorded simultaneously with membrane potential or current. Using these methods it is possible to study the role of changes of the intracellular calcium concentration produced by synaptic activity and action potential firing of individual neurons. In this presentation we demonstrate the methods to simultaneously record electrophysiological activity along with intracellular calcium from individual SCN neurons maintained in brain slices. PMID:24335611

  12. Electrophysiological Effects of Dexmedetomidine on Sinoatrial Nodes of Rabbits

    PubMed Central

    Pan, Xia; Zhang, Zhen; Huang, Ya-Yi; Zhao, Jing; Wang, Long

    2015-01-01

    Background The purpose of this study was to investigate the electrophysiological effects of dexmedetomidine on pacemaker cells in sinoatrial nodes of rabbits. Methods Healthy rabbits were anesthetized intravenously with sodium pentobarbital, and the hearts were quickly dissected and mounted in a tissue bath. Machine-pulled glass capillary microelectrodes which were connected to a high input impedance amplifier and impaled in dominant pacemaker cells. Thereafter, an intracellular microelectrode technique was used to record action potential. Results The amplitude of action potential, velocity of diastolic (phase 4) depolarization, and rate of pacemaker firing in normal pacemaker cells in sinoatrial node were decreased by use of dexmedetomidine (0.5 ng/ml, 5 ng/ml, 50 ng/ml) in a concentration-dependent manner. Pretreatment with yohimbine (1 μM), did not alter the effects of dexmedetomidine (5 ng/ml) on sinoatrial node pacemaker cells. Pretreatment with CsCl (2 mmol/L), dexmedetomidine (5 ng/ml) decreased the amplitude of action potential, but had no significant effect on other parameters of action potential. Conclusions Dexmedetomidine exerts inhibitory electrophysiological effects on pacemaker cells in sinoatrial nodes of rabbits in a concentration-dependent manner, which may not be mediated by alpha 2-adrenoreceptor. PMID:27122920

  13. Electrophysiological recording in the brain of intact adult zebrafish.

    PubMed

    Johnston, Lindsey; Ball, Rebecca E; Acuff, Seth; Gaudet, John; Sornborger, Andrew; Lauderdale, James D

    2013-01-01

    Previously, electrophysiological studies in adult zebrafish have been limited to slice preparations or to eye cup preparations and electrorentinogram recordings. This paper describes how an adult zebrafish can be immobilized, intubated, and used for in vivo electrophysiological experiments, allowing recording of neural activity. Immobilization of the adult requires a mechanism to deliver dissolved oxygen to the gills in lieu of buccal and opercular movement. With our technique, animals are immobilized and perfused with habitat water to fulfill this requirement. A craniotomy is performed under tricaine methanesulfonate (MS-222; tricaine) anesthesia to provide access to the brain. The primary electrode is then positioned within the craniotomy window to record extracellular brain activity. Through the use of a multitube perfusion system, a variety of pharmacological compounds can be administered to the adult fish and any alterations in the neural activity can be observed. The methodology not only allows for observations to be made regarding changes in neurological activity, but it also allows for comparisons to be made between larval and adult zebrafish. This gives researchers the ability to identify the alterations in neurological activity due to the introduction of various compounds at different life stages. PMID:24300281

  14. Verification of computational models of cardiac electro-physiology.

    PubMed

    Pathmanathan, Pras; Gray, Richard A

    2014-05-01

    For computational models of cardiac activity to be used in safety-critical clinical decision-making, thorough and rigorous testing of the accuracy of predictions is required. The field of 'verification, validation and uncertainty quantification' has been developed to evaluate the credibility of computational predictions. The first stage, verification, is the evaluation of how well computational software correctly solves the underlying mathematical equations. The aim of this paper is to introduce novel methods for verifying multi-cellular electro-physiological solvers, a crucial first stage for solvers to be used with confidence in clinical applications. We define 1D-3D model problems with exact solutions for each of the monodomain, bidomain, and bidomain-with-perfusing-bath formulations of cardiac electro-physiology, which allow for the first time the testing of cardiac solvers against exact errors on fully coupled problems in all dimensions. These problems are carefully constructed so that they can be easily run using a general solver and can be used to greatly increase confidence that an implementation is correct, which we illustrate by testing one major solver, 'Chaste', on the problems. We then perform case studies on calculation verification (also known as solution verification) for two specific applications. We conclude by making several recommendations regarding verification in cardiac modelling. PMID:24259465

  15. Subjective Stress, Salivary Cortisol, and Electrophysiological Responses to Psychological Stress

    PubMed Central

    Qi, Mingming; Gao, Heming; Guan, Lili; Liu, Guangyuan; Yang, Juan

    2016-01-01

    The present study aimed to investigate the subjective stress, salivary cortisol, and electrophysiological responses to psychological stress induced by a modified version of a mental arithmetic task. Fifteen participants were asked to estimate whether the multiplication product of two-decimal numbers was above 10 or not either with a time limit (the stress condition) or without a time limit (the control condition). The results showed that participants reported higher levels of stress, anxiety, and negative affect in the stress condition than they did in the control condition. Moreover, the salivary cortisol level continued to increase after the stress condition but exhibited a sharp decrease after the control condition. In addition, the electrophysiological data showed that the amplitude of the frontal-central N1 component was larger for the stress condition than it was for the control condition, while the amplitude of the frontal-central P2 component was larger for the control condition than it was for the stress condition. Our study suggests that the psychological stress characteristics of time pressure and social-evaluative threat caused dissociable effects on perception and on the subsequent attentional resource allocation of visual information. PMID:26925026

  16. Relationship of Vascular Factors on Electrophysiologic Severity of Diabetic Neuropathy

    PubMed Central

    Hwang, Jeong-Won; Kwon, Hee Kyu

    2016-01-01

    Objective To investigate the impact of vascular factors on the electrophysiologic severity of diabetic neuropathy (DPN). Methods Total 530 patients with type 2 diabetes were enrolled retrospectively. We rated severity of DPN from 1 (normal) to 4 (severe) based on electrophysiologic findings. We collected the data concerning vascular factors (including brachial-ankle pulse wave velocity [PWV], ankle brachial index, ultrasound of carotid artery, lipid profile from the blood test, and microalbuminuria [MU] within 24 hours urine), and metabolic factors of diabetes (such as glycated hemoglobin [HbA1c]). We analyzed the differences among the four subgroups using χ2 test and ANOVA, and ordinal logistic regression analysis was performed to investigate the relationship between significant variables and severity of DPN. Results The severity of DPN was significantly associated with duration of diabetes, HbA1c, existence of diabetic retinopathy and nephropathy, PWV, presence of plaque, low density lipoprotein-cholesterol and MU (p<0.05). Among these variables, HbA1c and presence of plaque were more significantly related with severity of DPN in logistic regression analysis (p<0.001), and presence of plaque showed the highest odds ratio (OR=2.52). Conclusion Our results suggest that markers for vascular wall properties, such as PWV and presence of plaque, are significantly associated with the severity of DPN. The presence of plaque was more strongly associated with the severity of DPN than other variables. PMID:26949670

  17. Three electrophysiological phenotypes of cultured human umbilical vein endothelial cells.

    PubMed

    Yu, K; Ruan, D Y; Ge, S Y

    2002-09-01

    The conventional whole cell patch-clamp technique was used to measure the resting membrane conductance and membrane currents of nonstimulated cultured human umbilical vein endothelial cells (HUVECs) in different ionic conditions. Three electrophysiological phenotypes of cultured HUVECs (n = 122) were determined: first, 20% of cells as type I mainly displaying the inwardly rectifying potassium current (IKi); second, 38% of cells as type II in which IKi was super-posed on a TEA-sensitive, delayed rectifying current; third, 27% of cells as type III predominantly displaying the outwardly rectifying current which was sensitive to TEA and slightly inhibited by a chloride channel blocker niflumic acid (N.A.). In cells of type I, the mean zero-current potential (V0) was dependent on extracellular K+ ([K+]o) but not on Cl-, indicating major permeability to K+. Whereas V0 of type II was also affected by extracellular Cl- ([Cl-]o), indicating the contribution of an outward Cl- current in setting V0. The cells of type III were not sensitive to decrease of [Cl-]o and the outward current was activated in a relative stable voltage range. This varying phenotypic expression and multipotential behavior of HUVECs suggests that the electrical features of HUVEC may be primarily determined by embryonic origin and local effect of the microenvironment. This research provided the detailed electrophysiological knowledge of the endothelial cells. PMID:12537354

  18. Use of electrophysiological monitoring in selective rhizotomy treating glossopharyngeal neuralgia.

    PubMed

    Zhang, Wenhao; Chen, Minjie; Zhang, Weijie; Chai, Ying

    2014-07-01

    The aim of this study was to evaluate the effects of electrophysiological monitoring on selective rhizotomy of the glossopharyngeal nerve (SRGN) in treatment of glossopharyngeal neuralgia (GPN). From December, 2009 to May, 2012, SRGN was carried out on 8 patients with GPN, through a suboccipital sigmoid sinus posterior approach. The electrodes were placed on the cricothyroid muscle (vagus nerve). Two groups of amplitudes (A1 and A2) were recorded. A1 was recorded when the mixed nerve root was stimulated, and A2 when the part of the vagus nerve was stimulated. The glossopharyngeal nerve was sectioned and the vagus nerve was preserved. If A1/A2 < 50%, the mixed nerve root should be sectioned, otherwise the mixed nerve root should be retained. As the representation of vagus nerve, the averages of A1 and A2 were 22 and 36 μV respectively. The 8 patients were followed up for 9-39 months. Seven patients (87.5%) obtained complete pain relief (excellent) without complications such as hoarseness, dysphagia, and cough. One case (12.5%) obtained moderate relief (good), and was under control with carbamazepine at a dosage of 600 mg/d. Cough was occurred in this patient, but relieved in two months. Electrophysiological monitoring in SRGN can improve the efficiency of pain relief and reduce the incidence of complications. PMID:24095216

  19. Obesity, Cardiovascular Fitness, and Inhibition Function: An Electrophysiological Study

    PubMed Central

    Song, Tai-Fen; Chi, Lin; Chu, Chien-Heng; Chen, Feng-Tzu; Zhou, Chenglin; Chang, Yu-Kai

    2016-01-01

    The purpose of the present study was to examine how obesity and cardiovascular fitness are associated with the inhibition aspect of executive function from behavioral and electrophysiological perspectives. One hundred college students, aged 18–25 years, were categorized into four groups of equal size on the basis of body mass index and cardiovascular fitness: a normal-weight and high-fitness (NH) group, an obese-weight and high-fitness (OH) group, a normal-weight and low-fitness (NL) group, and an obese-weight and low-fitness (OL) group. Behavioral measures of response time and number of errors, as well as event-related potential measures of P3 and N1, were assessed during the Stroop Task. The results revealed that, in general, the NH group exhibited shorter response times and larger P3 amplitudes relative to the NL and OL groups, wherein the OL group exhibited the longest response time in the incongruent condition. No group differences in N1 indices were also revealed. These findings suggest that the status of being both normal weight and having high cardiovascular fitness is associated with better behavioral and later stages of electrophysiological indices of cognitive function. PMID:27512383

  20. Electrophysiological study of intravenous pinaverium bromide in cardiology.

    PubMed

    Guerot, C; Khemache, A; Sebbah, J; Noel, B

    1988-01-01

    Pinaverium bromide is a musculotropic spasmolytic agent which acts by inhibiting transmembrane calcium movements, an effect similar to that of verapamil. Because of this, an investigation was carried out to see if it had any electrophysiological effects in patients with various cardiac disorders. In an open study, 10 patients received 2 mg pinaverium bromide intravenously. In a double-blind study, 10 patients received 4 mg pinaverium bromide intravenously and 10 patients placebo. Patients included those with either normal or pathological basal conduction, such as bundle-branch block and 1st degree atrioventricular block. Measurements were made of electrophysiological parameters before and 10 minutes after injection. The results showed that neither of the two doses of pinaverium bromide had any effect on atrial excitability, sino-atrial conduction, node and trunk atrioventricular conduction or on intraventricular conduction. No significant difference was seen in comparison with placebo. Pinaverium bromide had no anti-arrhythmic properties in these studies. Local, cardiac and general clinical tolerability was good in all patients. PMID:3219882

  1. Obesity, Cardiovascular Fitness, and Inhibition Function: An Electrophysiological Study.

    PubMed

    Song, Tai-Fen; Chi, Lin; Chu, Chien-Heng; Chen, Feng-Tzu; Zhou, Chenglin; Chang, Yu-Kai

    2016-01-01

    The purpose of the present study was to examine how obesity and cardiovascular fitness are associated with the inhibition aspect of executive function from behavioral and electrophysiological perspectives. One hundred college students, aged 18-25 years, were categorized into four groups of equal size on the basis of body mass index and cardiovascular fitness: a normal-weight and high-fitness (NH) group, an obese-weight and high-fitness (OH) group, a normal-weight and low-fitness (NL) group, and an obese-weight and low-fitness (OL) group. Behavioral measures of response time and number of errors, as well as event-related potential measures of P3 and N1, were assessed during the Stroop Task. The results revealed that, in general, the NH group exhibited shorter response times and larger P3 amplitudes relative to the NL and OL groups, wherein the OL group exhibited the longest response time in the incongruent condition. No group differences in N1 indices were also revealed. These findings suggest that the status of being both normal weight and having high cardiovascular fitness is associated with better behavioral and later stages of electrophysiological indices of cognitive function. PMID:27512383

  2. Correlations of clinical, neuroimaging, and electrophysiological features in Hirayama disease

    PubMed Central

    Liao, Ming-Feng; Chang, Hong-Shiu; Chang, Kuo-Hsuan; Ro, Long-Sun; Chu, Chun-Che; Kuo, Hung-Chou; Lyu, Rong-Kuo

    2016-01-01

    Abstract Hirayama disease (HD) is characterized by development of asymmetric forearm muscle atrophy during adolescence with or without focal cervical spinal cord atrophy. The purpose of this study is to assess the correlation of clinical symptoms, disease progression, and electrophysiological findings with cervical spine magnetic resonance imaging (MRI) findings. The medical records, cervical spine MRIs, and electrophysiological findings of 44 HD patients were retrospectively reviewed and analyzed. Denervation changes in any single C5 to C7 root-innervated muscle (deltoid, biceps, triceps, or extensor digitorum communis) occurred more frequently in the 25 patients with cord atrophy than the 19 patients without cord atrophy (88% vs 53%, P = 0.02). Onset age, duration of disease progression, neurological examinations, nerve conduction study, and electromyographic findings from individual muscles were similar between patient groups. Compared with HD patients without cord atrophy, HD patients with cord atrophy experience a more severe denervation change in C5 to C7 root-innervated muscles. PMID:27428223

  3. Simulation Methods and Validation Criteria for Modeling Cardiac Ventricular Electrophysiology

    PubMed Central

    Krishnamoorthi, Shankarjee; Perotti, Luigi E.; Borgstrom, Nils P.; Ajijola, Olujimi A.; Frid, Anna; Ponnaluri, Aditya V.; Weiss, James N.; Qu, Zhilin; Klug, William S.; Ennis, Daniel B.; Garfinkel, Alan

    2014-01-01

    We describe a sequence of methods to produce a partial differential equation model of the electrical activation of the ventricles. In our framework, we incorporate the anatomy and cardiac microstructure obtained from magnetic resonance imaging and diffusion tensor imaging of a New Zealand White rabbit, the Purkinje structure and the Purkinje-muscle junctions, and an electrophysiologically accurate model of the ventricular myocytes and tissue, which includes transmural and apex-to-base gradients of action potential characteristics. We solve the electrophysiology governing equations using the finite element method and compute both a 6-lead precordial electrocardiogram (ECG) and the activation wavefronts over time. We are particularly concerned with the validation of the various methods used in our model and, in this regard, propose a series of validation criteria that we consider essential. These include producing a physiologically accurate ECG, a correct ventricular activation sequence, and the inducibility of ventricular fibrillation. Among other components, we conclude that a Purkinje geometry with a high density of Purkinje muscle junctions covering the right and left ventricular endocardial surfaces as well as transmural and apex-to-base gradients in action potential characteristics are necessary to produce ECGs and time activation plots that agree with physiological observations. PMID:25493967

  4. Electrophysiological Auditory Responses and Language Development in Infants with Periventricular Leukomalacia

    ERIC Educational Resources Information Center

    Avecilla-Ramirez, G. N.; Ruiz-Correa, S.; Marroquin, J. L.; Harmony, T.; Alba, A.; Mendoza-Montoya, O.

    2011-01-01

    This study presents evidence suggesting that electrophysiological responses to language-related auditory stimuli recorded at 46 weeks postconceptional age (PCA) are associated with language development, particularly in infants with periventricular leukomalacia (PVL). In order to investigate this hypothesis, electrophysiological responses to a set…

  5. 48 CFR 35.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-reimbursement contracts is usually appropriate (see subpart 16.3). The nature of development work often requires... SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 35.006 Contracting methods and..., performance objectives, and specifications for the work can be defined will largely determine the type...

  6. 48 CFR 35.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-reimbursement contracts is usually appropriate (see subpart 16.3). The nature of development work often requires... SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 35.006 Contracting methods and..., performance objectives, and specifications for the work can be defined will largely determine the type...

  7. 48 CFR 35.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-reimbursement contracts is usually appropriate (see subpart 16.3). The nature of development work often requires... SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 35.006 Contracting methods and..., performance objectives, and specifications for the work can be defined will largely determine the type...

  8. 48 CFR 235.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... development contract or a fixed-price type contract for the lead ship of a class, when the value of the work... REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT... production option on a development contract for a major weapon system reasonably in advance of the...

  9. 48 CFR 235.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... development contract or a fixed-price type contract for the lead ship of a class, when the value of the work... REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT... production option on a development contract for a major weapon system reasonably in advance of the...

  10. NeuroChip: A Microfluidic Electrophysiological Device for Genetic and Chemical Biology Screening of Caenorhabditis elegans Adult and Larvae

    PubMed Central

    Hu, Chunxiao; Dillon, James; Kearn, James; Murray, Caitriona; O’Connor, Vincent; Holden-Dye, Lindy; Morgan, Hywel

    2013-01-01

    Genetic and chemical biology screens of C. elegans have been of enormous benefit in providing fundamental insight into neural function and neuroactive drugs. Recently the exploitation of microfluidic devices has added greater power to this experimental approach providing more discrete and higher throughput phenotypic analysis of neural systems. Here we make a significant addition to this repertoire through the design of a semi-automated microfluidic device, NeuroChip, which has been optimised for selecting worms based on the electrophysiological features of the pharyngeal neural network. We demonstrate this device has the capability to sort mutant from wild-type worms based on high definition extracellular electrophysiological recordings. NeuroChip resolves discrete differences in excitatory, inhibitory and neuromodulatory components of the neural network from individual animals. Worms may be fed into the device consecutively from a reservoir and recovered unharmed. It combines microfluidics with integrated electrode recording for sequential trapping, restraining, recording, releasing and recovering of C. elegans. Thus mutant worms may be selected, recovered and propagated enabling mutagenesis screens based on an electrophysiological phenotype. Drugs may be rapidly applied during the recording thus permitting compound screening. For toxicology, this analysis can provide a precise description of sub-lethal effects on neural function. The chamber has been modified to accommodate L2 larval stages showing applicability for small size nematodes including parasitic species which otherwise are not tractable to this experimental approach. We also combine NeuroChip with optogenetics for targeted interrogation of the function of the neural circuit. NeuroChip thus adds a new tool for exploitation of C. elegans and has applications in neurogenetics, drug discovery and neurotoxicology. PMID:23717588

  11. Whole-Retina Reduced Electrophysiological Activity in Mice Bearing Retina-Specific Deletion of Vesicular Acetylcholine Transporter

    PubMed Central

    Bedore, Jake; Martyn, Amanda C.; Li, Anson K. C.; Dolinar, Eric A.; McDonald, Ian S.; Coupland, Stuart G.; Prado, Vania F.; Prado, Marco A.; Hill, Kathleen A.

    2015-01-01

    Background Despite rigorous characterization of the role of acetylcholine in retinal development, long-term effects of its absence as a neurotransmitter are unknown. One of the unanswered questions is how acetylcholine contributes to the functional capacity of mature retinal circuits. The current study investigates the effects of disrupting cholinergic signalling in mice, through deletion of vesicular acetylcholine transporter (VAChT) in the developing retina, pigmented epithelium, optic nerve and optic stalk, on electrophysiology and structure of the mature retina. Methods & Results A combination of electroretinography, optical coherence tomography imaging and histological evaluation assessed retinal integrity in mice bearing retina- targeted (embryonic day 12.5) deletion of VAChT (VAChTSix3-Cre-flox/flox) and littermate controls at 5 and 12 months of age. VAChTSix3-Cre-flox/flox mice did not show any gross changes in nuclear layer cellularity or synaptic layer thickness. However, VAChTSix3-Cre-flox/flox mice showed reduced electrophysiological response of the retina to light stimulus under scotopic conditions at 5 and 12 months of age, including reduced a-wave, b-wave, and oscillatory potential (OP) amplitudes and decreased OP peak power and total energy. Reduced a-wave amplitude was proportional to the reduction in b-wave amplitude and not associated with altered a-wave 10%-90% rise time or inner and outer segment thicknesses. Significance This study used a novel genetic model in the first examination of function and structure of the mature mouse retina with disruption of cholinergic signalling. Reduced amplitude across the electroretinogram wave form does not suggest dysfunction in specific retinal cell types and could reflect underlying changes in the retinal and/or extraretinal microenvironment. Our findings suggest that release of acetylcholine by VAChT is essential for the normal electrophysiological response of the mature mouse retina. PMID:26226617

  12. Development of microfluidic system and optical tweezers for electrophysiological investigations of an individual cell

    NASA Astrophysics Data System (ADS)

    Alrifaiy, A.; Bitaraf, N.; Lindahl, O.; Ramser, K.

    2010-08-01

    We present a new approach of combining Lab-on-a-chip technologies with optical manipulation technique for accurate investigations in the field of cell biology. A general concept was to develop and combine different methods to perform advanced electrophysiological investigations of an individual living cell under optimal control of the surrounding environment. The conventional patch clamp technique was customized by modifying the open system with a gas-tight multifunctional microfluidics system and optical trapping technique (optical tweezers). The system offers possibilities to measure the electrical signaling and activity of the neuron under optimum conditions of hypoxia and anoxia while the oxygenation state is controlled optically by means of a spectroscopic technique. A cellbased microfluidics system with an integrated patch clamp pipette was developed successfully. Selectively, an individual neuron is manipulated within the microchannels of the microfluidic system under a sufficient control of the environment. Experiments were performed to manipulate single yeast cell and red blood cell (RBC) optically through the microfluidics system toward an integrated patch clamp pipette. An absorption spectrum of a single RCB was recorded which showed that laser light did not impinge on the spectroscopic spectrum of light. This is promising for further development of a complete lab-on-a-chip system for patch clamp measurements.

  13. Affine Contractions on the Plane

    ERIC Educational Resources Information Center

    Celik, D.; Ozdemir, Y.; Ureyen, M.

    2007-01-01

    Contractions play a considerable role in the theory of fractals. However, it is not easy to find contractions which are not similitudes. In this study, it is shown by counter examples that an affine transformation of the plane carrying a given triangle onto another triangle may not be a contraction even if it contracts edges, heights or medians.…

  14. Virtual NEURON: a strategy for merged biochemical and electrophysiological modeling.

    PubMed

    Brown, Sherry-Ann; Moraru, Ion I; Schaff, James C; Loew, Leslie M

    2011-10-01

    Because of its highly branched dendrite, the Purkinje neuron requires significant computational resources if coupled electrical and biochemical activity are to be simulated. To address this challenge, we developed a scheme for reducing the geometric complexity; while preserving the essential features of activity in both the soma and a remote dendritic spine. We merged our previously published biochemical model of calcium dynamics and lipid signaling in the Purkinje neuron, developed in the Virtual Cell modeling and simulation environment, with an electrophysiological model based on a Purkinje neuron model available in NEURON. A novel reduction method was applied to the Purkinje neuron geometry to obtain a model with fewer compartments that is tractable in Virtual Cell. Most of the dendritic tree was subject to reduction, but we retained the neuron's explicit electrical and geometric features along a specified path from spine to soma. Further, unlike previous simplification methods, the dendrites that branch off along the preserved explicit path are retained as reduced branches. We conserved axial resistivity and adjusted passive properties and active channel conductances for the reduction in surface area, and cytosolic calcium for the reduction in volume. Rallpacks are used to validate the reduction algorithm and show that it can be generalized to other complex neuronal geometries. For the Purkinje cell, we found that current injections at the soma were able to produce similar trains of action potentials and membrane potential propagation in the full and reduced models in NEURON; the reduced model produces identical spiking patterns in NEURON and Virtual Cell. Importantly, our reduced model can simulate communication between the soma and a distal spine; an alpha function applied at the spine to represent synaptic stimulation gave similar results in the full and reduced models for potential changes associated with both the spine and the soma. Finally, we combined

  15. Virtual NEURON: a strategy for merged biochemical and electrophysiological modeling

    PubMed Central

    Brown, Sherry-Ann; Moraru, Ion I.; Schaff, James C.

    2011-01-01

    Because of its highly branched dendrite, the Purkinje neuron requires significant computational resources if coupled electrical and biochemical activity are to be simulated. To address this challenge, we developed a scheme for reducing the geometric complexity; while preserving the essential features of activity in both the soma and a remote dendritic spine. We merged our previously published biochemical model of calcium dynamics and lipid signaling in the Purkinje neuron, developed in the Virtual Cell modeling and simulation environment, with an electrophysiological model based on a Purkinje neuron model available in NEURON. A novel reduction method was applied to the Purkinje neuron geometry to obtain a model with fewer compartments that is tractable in Virtual Cell. Most of the dendritic tree was subject to reduction, but we retained the neuron’s explicit electrical and geometric features along a specified path from spine to soma. Further, unlike previous simplification methods, the dendrites that branch off along the preserved explicit path are retained as reduced branches. We conserved axial resistivity and adjusted passive properties and active channel conductances for the reduction in surface area, and cytosolic calcium for the reduction in volume. Rallpacks are used to validate the reduction algorithm and show that it can be generalized to other complex neuronal geometries. For the Purkinje cell, we found that current injections at the soma were able to produce similar trains of action potentials and membrane potential propagation in the full and reduced models in NEURON; the reduced model produces identical spiking patterns in NEURON and Virtual Cell. Importantly, our reduced model can simulate communication between the soma and a distal spine; an alpha function applied at the spine to represent synaptic stimulation gave similar results in the full and reduced models for potential changes associated with both the spine and the soma. Finally, we combined

  16. Human melanocytes mitigate keratinocyte-dependent contraction in an in vitro collagen contraction assay.

    PubMed

    Rakar, Jonathan; Krammer, Markus P; Kratz, Gunnar

    2015-08-01

    Scarring is an extensive problem in burn care, and treatment can be especially complicated in cases of hypertrophic scarring. Contraction is an important factor in scarring but the contribution of different cell types remains unclear. We have investigated the contractile behavior of keratinocytes, melanocytes and fibroblasts by using an in vitro collagen gel assay aimed at identifying a modulating role of melanocytes in keratinocyte-mediated contraction. Cells were seeded on a collagen type I gel substrate and the change in gel dimensions were measured over time. Hematoxylin & Eosin-staining and immunohistochemistry against pan-cytokeratin and microphthalmia-associated transcription factor showed that melanocytes integrated between keratinocytes and remained there throughout the experiments. Keratinocyte- and fibroblast-seeded gels contracted significantly over time, whereas melanocyte-seeded gels did not. Co-culture assays showed that melanocytes mitigate the keratinocyte-dependent contraction (significantly slower and 18-32% less). Fibroblasts augmented the contraction in most assays (approximately 6% more). Non-contact co-cultures showed some influence on the keratinocyte-dependent contraction. Results show that mechanisms attributable to melanocytes, but not fibroblasts, can mitigate keratinocyte contractile behavior. Contact-dependent mechanisms are stronger modulators than non-contact dependent mechanisms, but both modes carry significance to the contraction modulation of keratinocytes. Further investigations are required to determine the mechanisms involved and to determine the utility of melanocytes beyond hypopigmentation in improved clinical regimes of burn wounds and wound healing. PMID:25466959

  17. Nested and Dynamic Contract Boundaries

    NASA Astrophysics Data System (ADS)

    Strickland, T. Stephen; Felleisen, Matthias

    Previous work on software contracts assumes fixed and statically known boundaries between the parties to a contract. Implementations of contract monitoring systems rely on this assumption to explain the nature of contract violations and to assign blame to violators. In this paper, we explain how to implement arbitrary, nested, and dynamic contract boundaries with two examples. First, we add nestable contract regions to a static, first-order module system. Second, we show that even a dynamic, higher-order, and hierarchical module system can be equipped with software contracts that support precise blame assignment.

  18. Electrophysiologic Assessment of Auditory Training Benefits in Older Adults.

    PubMed

    Anderson, Samira; Jenkins, Kimberly

    2015-11-01

    Older adults often exhibit speech perception deficits in difficult listening environments. At present, hearing aids or cochlear implants are the main options for therapeutic remediation; however, they only address audibility and do not compensate for central processing changes that may accompany aging and hearing loss or declines in cognitive function. It is unknown whether long-term hearing aid or cochlear implant use can restore changes in central encoding of temporal and spectral components of speech or improve cognitive function. Therefore, consideration should be given to auditory/cognitive training that targets auditory processing and cognitive declines, taking advantage of the plastic nature of the central auditory system. The demonstration of treatment efficacy is an important component of any training strategy. Electrophysiologic measures can be used to assess training-related benefits. This article will review the evidence for neuroplasticity in the auditory system and the use of evoked potentials to document treatment efficacy. PMID:27587912

  19. Electrophysiologic studies of the thoracic limb of the horse.

    PubMed

    Blythe, L L; Kitchell, R L

    1982-09-01

    The cutaneous innervation of the thoracic limb was investigated in 18 barbiturate-anesthetized horses, using electrophysiologic techniques. The cutaneous area (CA) innervated by each cutaneous nerve was delineated in at least 4 horses by stroking the hairs with a small watercolor brush while recording from the nerve. Mapping of adjacent CA revealed areas of considerable overlap. The part of a CA of a given nerve supplied only by that nerve is referred to as its autonomous zone (AZ). In contrast to the standard textbook illustrations cutaneous branches of the axillary, radial, musculocutaneous, and ulnar nerves overlapped extensively in the antebrachium. Clinically testable AZ were found in the antebrachium for the caudal cutaneous antebrachial nerve of the ulnar nerve and in the carpus and manus for the cutaneous branches of the median, ulnar, and musculocutaneous nerves; AZ were not found for the cutaneous branches of the radial and axillary nerves. PMID:7149398

  20. The year in review of clinical cardiac electrophysiology.

    PubMed

    Marcus, Gregory M; Keung, Edmund; Scheinman, Melvin M

    2013-02-19

    This past year saw multiple important advances in the field clinical cardiac electrophysiology. Seminal articles describing new anticoagulant drugs for stroke prevention in atrial fibrillation were published. New results that raise questions regarding the safety of dronedarone and several new promising techniques in AF ablation were described. Important articles that refine our understanding of the risk of sudden death among Wolff-Parkinson-White patients were published. In the basic and translational sciences, the application of gene therapy to the study and potential treatment of arrhythmias was described, whereas genetic determinants important to the optimal treatment of inherited arrhythmia syndromes were further elucidated. Issues relevant to cardiac rhythm device therapy included investigations into the St. Jude Riata lead, new applications of device monitoring, predicting response to cardiac resynchronization therapy, and the use of pacemakers for vasovagal syncope. PMID:23312706

  1. Electrophysiological markers of genetic risk for attention deficit hyperactivity disorder

    PubMed Central

    Tye, Charlotte; McLoughlin, Gráinne; Kuntsi, Jonna; Asherson, Philip

    2014-01-01

    Electroencephalography (EEG) is an ideal neuroscientific approach, providing a direct measurement of neural activity that demonstrates reliability, developmental stability and high heritability. This systematic review of a subset of domains evaluates the utility of electrophysiological measures as potential intermediate phenotypes for ADHD in the domains of quantitative EEG indices of arousal and intra-individual variability, and functional investigations of inhibitory and error processing using the event-related potential (ERP) technique. Each domain demonstrates consistent and meaningful associations with ADHD, a degree of genetic overlap with ADHD and potential links to specific genetic variants. Investigations of the genetic and environmental contributions to EEG/ERP and shared genetic overlap with ADHD may enhance molecular genetic studies and provide novel insights into aetiology. Such research will aid in the precise characterisation of the clinical deficits seen in ADHD and guide the development of novel intervention and prevention strategies for those at risk. PMID:21426626

  2. The sense of smell in Odonata: an electrophysiological screening.

    PubMed

    Piersanti, Silvana; Frati, Francesca; Conti, Eric; Rebora, Manuela; Salerno, Gianandrea

    2014-11-01

    Volatile chemicals mediate a great range of intra- and interspecific signalling and information in insects. Olfaction has been widely investigated mostly in Neoptera while the knowledge of this sense in most basal insects such as Paleoptera (Odonata and Ephemeroptera) is still poor. In the present study we show the results of an electrophysiological screening on two model species, Libellula depressa (Libellulidae) and Ischnura elegans (Coenagrionidae), representatives of the two Odonata suborders Anisoptera and Zygoptera, with the aim to deep the knowledge on the sense of smell of this insect order. The antennal olfactory sensory neurons (OSNs) of these two species responded to the same 22 compounds (out of 48 chemicals belonging to different functional groups) encompassing mostly amines, carboxylic acids or aldehydes and belonging to green leaf volatiles, vertebrate related volatiles and volatiles emitted by standing waters bacteria. The properties of Odonata OSNs are very similar to those of ionotropic receptors (IRs) expressing OSNs in other insects. PMID:25218659

  3. Conceptual fluency increases recollection: behavioral and electrophysiological evidence

    PubMed Central

    Wang, Wei; Li, Bingbing; Gao, Chuanji; Xu, Huifang; Guo, Chunyan

    2015-01-01

    It is widely established that fluency can contribute to recognition memory. Previous studies have found that enhanced fluency increases familiarity, but not recollection. The present study was motivated by a previous finding that conceptual priming affected recollection. We used event-related potentials to investigate the electrophysiological correlates of these effects with conceptually related two-character Chinese words. We found that previous conceptual priming effects on conceptual fluency only increased the incidence of recollection responses. We also found that enhanced conceptual fluency was associated with N400 attenuation, which was also correlated with the behavioral indicator of recollection. These results suggest that the N400 effect might be related to the impact of conceptual fluency on recollection recognition. These study findings provide further evidence for the relationship between fluency and recollection. PMID:26175678

  4. Classification, Electrophysiological Features and Therapy of Atrioventricular Nodal Reentrant Tachycardia

    PubMed Central

    Josephson, Mark E

    2016-01-01

    Atrioventricular nodal reentrant tachycardia (AVNRT) should be classified as typical or atypical. The term ‘fast-slow AVNRT’ is rather misleading. Retrograde atrial activation during tachycardia should not be relied upon as a diagnostic criterion. Both typical and atypical atrioventricular nodal reentrant tachycardia are compatible with varying retrograde atrial activation patterns. Attempts at establishing the presence of a ‘lower common pathway’ are probably of no practical significance. When the diagnosis of AVNRT is established, ablation should be only directed towards the anatomic position of the slow pathway. If right septal attempts are unsuccessful, the left septal side should be tried. Ablation targeting earliest atrial activation sites during typical atrioventricular nodal reentrant tachycardia or the fast pathway in general for any kind of typical or atypical atrioventricular nodal reentrant tachycardia, are not justified. In this review we discuss current concepts about the tachycardia circuit, electrophysiologic diagnosis, and ablation of this arrhythmia.

  5. Photochromic Potassium Channel Blockers: Design and Electrophysiological Characterization

    PubMed Central

    Mourot, Alexandre; Fehrentz, Timm; Kramer, Richard H.

    2016-01-01

    Voltage-gated potassium (Kv) channels are membrane proteins that open a selective pore upon membrane depolarization, allowing K+ ions to flow down their electrochemical gradient. In neurons, Kv channels play a key role in repolarizing the membrane potential during the falling phase of the action potential, often resulting in an after hyperpolarization. Opening of Kv channels results in a decrease of cellular excitability, whereas closing (or pharmacological block) has the opposite effect, increased excitability. We have developed a series of photosensitive blockers for Kv channels that enable reversible, optical regulation of potassium ion flow. Such molecules can be used for remote control of neuronal excitability using light as an on/off switch. Here we describe the design and electrophysiological characterization of photochromic blockers of ion channels. Our focus is on Kv channels but in principle, the techniques described here can be applied to other ion channels and signaling proteins. PMID:23494374

  6. Ataxia telangiectasia in Chinese children. A clinical and electrophysiological study.

    PubMed

    Wong, V; Yu, Y L; Chan-Lui, W Y; Woo, E; Yeung, C Y

    1987-01-01

    The clinical manifestations, immunological, chromosomal, and multimodal electrophysiological studies of five Chinese patients with ataxia telangiectasia are described. One died of hepatocellular carcinoma not associated with Hepatitis B-antigenaemia. Another died of respiratory failure. Two siblings are free of sinopulmonary infections although they are wheelchair bound. Computed tomography of the brain showed cerebellar atrophy in four cases. Nerve conduction studies showed evidence of axonal neuropathy in all cases with the earliest detection at six years. Electromyography showed mild denervation changes in two cases. Two patients had abnormal somatosensory evoked potentials and one had abnormal visual and brain stem auditory evoked potentials. The level of alpha foetal protein was elevated whereas the serum carcino-embryonic antigen was normal in all patients. PMID:3665286

  7. Low-energy x-ray irradiation for electrophysiological studies

    SciTech Connect

    Schauer, D.A.; Zeman, G.H.; Pellmar, T.C.

    1989-01-01

    High-dose-rate acute whole-body exposures have been the main focus of radiobiology research conducted at the Armed Forces Radiobiology Research Institute (AFRRI) for many years. Extensive quantitative studies have been conducted analyzing behavioral effects, radiation-induced syndromes, and combined injury phenomena. Tolliver and Pellmar initiated a study to evaluate radiation damage to brain neurophysiology. A 50-kVp molybdenum target/filter x-ray tube was installed inside a lead-shielded Faraday cage. High-dose rates of up to 1.54 Gy/min (17.4-keV weighted average photons) were used to conduct local in vitro irradiations of the hippocampal region of guinea pig brains. Electrophysiological recordings of subtle changes in neuronal activity indicate this system is suitable for this application.

  8. Pitfalls in Using Electrophysiological Studies to Diagnose Neuromuscular Disorders

    PubMed Central

    Koo, Yong Seo; Cho, Charles S.

    2012-01-01

    Electrodiagnostic testing is used widely for the full characterization of neuromuscular disorders and for providing unique information on the processes underlying the pathology of peripheral nerves and muscles. However, such testing should be considered as an extension of anamnesis and physical examination, not as pathognomonic of a specific disease entity. There are many pitfalls that could lead to erroneous interpretation of electrophysiological study results when the studies are not performed properly or if they are performed in the presence of anatomical aberrations. The diagnostic reliability of electrodiagnostic studies can be improved and the associated pitfalls overcome if the physician is familiar with all of those possible pitfalls. In this article we discuss the most common and important pitfalls associated with electrodiagnostic medicine. PMID:22523508

  9. Precise correlation between structural and electrophysiological disturbances in MADSAM neuropathy.

    PubMed

    Simon, Neil G; Kiernan, Matthew C

    2015-11-01

    Multifocal acquired demyelinating sensory and motor neuropathy is characterised by multifocal clinical deficits. Imaging studies have identified multifocal enlargements of nerve trunks, but a precise correlation between structural abnormalities and electrophysiological dysfunction has not been elucidated. Two patients diagnosed with multifocal acquired demyelinating sensory and motor neuropathy were evaluated with nerve conduction studies, including short segment nerve conduction studies to precisely localise motor conduction block, and ultrasound studies of corresponding nerve trunks. Motor conduction block was identified in each patient (upper limb nerves in two patients), superimposed on additional demyelinating neurophysiological features. Upper limb ultrasound studies demonstrated focal nerve enlargement that precisely correlated with neurophysiological conduction block. The results of this study suggest that factors contributing to focal structural abnormalities in multifocal acquired demyelinating sensory and motor neuropathy are also those that produce conduction block. PMID:26314279

  10. Is my voice just a familiar voice? An electrophysiological study

    PubMed Central

    Gomot, Marie; Roux, Sylvie; Bonnet-Brilhault, Frédérique; Bruneau, Nicole

    2015-01-01

    It is not clear whether self-stimuli are processed by the brain as highly familiar overlearned stimuli or as self-specific stimuli. This study examined the neural processes underlying discrimination of one’s own voice (OV) compared with a familiar voice (FV) using electrophysiological methods. Event-related potentials were recorded while healthy subjects (n = 15) listened passively to oddball sequences composed of recordings of the French vowel /a/ pronounced either by the participant her/himself, or by a familiar person or an unknown person. The results indicated that, although mismatch negativity displayed similar peak latency and amplitude in both conditions, the amplitude of the subsequent P3a was significantly smaller in response to OV compared with a FV. This study therefore indicated that fewer pre-attentional processes are involved in the discrimination of one’s OV than in the discrimination of FVs. PMID:24625786

  11. Processing inflectional and derivational morphology: electrophysiological evidence from Spanish.

    PubMed

    Alvarez, Carlos J; Urrutia, Mabel; Domínguez, Alberto; Sánchez-Casas, Rosa

    2011-02-18

    The goal of this paper is to study possible differences between the processing of inflectional vs. derivational morphology in Spanish word recognition using electrophysiological measures. A lexical decision task to target words preceded by morphological-related (or unrelated) primes was used. The orthographic and phonological overlap and the grammatical class for the two experimental conditions were exactly the same. Examples of the related conditions were, for inflection, NIÑO-NIÑA ("girl"-"boy"), and for derivation, RAMO-RAMA ("bunch"-"branch"). These conditions were compared with unrelated pairs without orthographic, phonological or semantic relationships. An attenuation of the N-400 component was found for both related conditions from 300 ms until 450 ms (until 500 ms for inflections only). In addition, different locations were suggested by the source analysis. These findings are consistent with accounts that argue for differences between the processing of inflections and derivations. PMID:21167910

  12. Cardiac electrophysiology in mice: a matter of size

    PubMed Central

    Kaese, Sven; Verheule, Sander

    2012-01-01

    Over the last decade, mouse models have become a popular instrument for studying cardiac arrhythmias. This review assesses in which respects a mouse heart is a miniature human heart, a suitable model for studying mechanisms of cardiac arrhythmias in humans and in which respects human and murine hearts differ. Section I considers the issue of scaling of mammalian cardiac (electro) physiology to body mass. Then, we summarize differences between mice and humans in cardiac activation (section II) and the currents underlying the action potential in the murine working myocardium (section III). Changes in cardiac electrophysiology in mouse models of heart disease are briefly outlined in section IV, while section V discusses technical considerations pertaining to recording cardiac electrical activity in mice. Finally, section VI offers general considerations on the influence of cardiac size on the mechanisms of tachy-arrhythmias. PMID:22973235

  13. [Electrophysiology principles of Na(+)/HCO3(-) cotransporters].

    PubMed

    Chen, Li-Ming; Liu, Mei; Liu, Ying

    2016-06-25

    Ion channels and transporters represent two major types of pathways of transmembrane transport for ions. Distinct from ion channels which conduct passive ionic diffusion, ion transporters mediate active transport of ions. In the perspective of biochemistry, ion transporters are enzymes that catalyze the movement of ions across the plasma membrane. In the present review, we selected the Na(+)/HCO3(-) cotransporter (NBC) as an example to analyze the key biochemical and biophysical properties of ion transporters, including stoichiometry, turnover number and transport capacity. Moreover, we provided an analysis of the electrophysiological principles of NBC based on the laws of thermodynamics. Based on the thermodynamical analysis, we showed how the stoichiometry of an NBC determines the direction of its ion transport. Finally, we reviewed the methodology for experimental determination of the stoichiometry of NBC, as well as the physiological significance of the stoichiometry of NBCs in specific tissues. PMID:27350205

  14. Microcomputer-based recording system for clinical electrophysiology.

    PubMed

    Török, B

    1990-09-01

    We developed a personal computer-based system for clinical electrophysiologic measurements. The computer interfaced with a commercially available A/D converter, a low-noise isolation preamplifier, filter circuits, pattern and Ganzfeld stimulators, and a hardcopy unit. Separate programs were developed for electroretinography (ERG), pattern ERG and simultaneous visual evoked potential (VEP), flash and pattern-shift VEP, and electro-oculographic measurements. The complete control of the applied hardware (eg, stimulus control, automatic gain, and filter selection) is a common feature of the computer programs. These programs provide oscilloscopic functions, overload protection, artifact elimination, averaging, automatic peak latency and amplitude determination, baseline correction, smoothing, and digital filtering. The results can be presented on matrix, laser printers, or digital plotters. The hardware components and the features of the driver software are demonstrated on normal and pathologic signals. PMID:2276319

  15. [Familial cerebellar ataxia: clinical, radiological and electrophysiological findings].

    PubMed

    Gajkowski, K; Rysz, A; Walecki, J; Bojakowski, J

    1988-01-01

    A family with cerebellar ataxia of late onset occurring in four generations was observed. Neurological abnormalities included signs of cerebellar ataxia, pyramidal tract damage and damage to the peripheral motor neuron. Computerized tomography demonstrated in five out of six studied patients an image suggesting olivo-ponto-cerebellar atrophy. In the cerebellar structures, brainstem and cerebral hemispheres evidence of atrophy was detected. No correlation was demonstrated between the intensity of the clinical signs and the progression of changes in CT image. Electrophysiological investigations demonstrated changes compatible with damage to the motor and sensory fibres in the peripheral nerves and signs suggesting damage to the spinal motor neurons and pyramidal tract. These observations confirm the multilevel development of the process. The use of similar diagnostic methods will permit a more accurate classification of cerebellar ataxia and obtaining of better information for prognostication of individual cases. PMID:3164096

  16. Electrophysiological correlates of cardiac sarcoidosis: an appraisal of current evidence.

    PubMed

    Yadava, Mrinal; Bala, Rupa

    2015-06-01

    Cardiac sarcoidosis is an underdiagnosed condition that may be present in as many as 25% of patients with systemic sarcoidosis. It is associated with significant morbidity and mortality in affected individuals. The presentation of cardiac involvement in sarcoidosis includes sudden death in the absence of preceding symptoms, conduction disturbances, ventricular arrhythmias, and heart failure. A scarcity of randomized data and a lack of prospective trials underlies the contention between experts on the most appropriate strategies for diagnosis and therapy. This review focuses on the electrophysiological sequelae of the disease, with an emphasis on current diagnostic guidelines, multimodality imaging for early detection, and the role of various therapeutic interventions. Multicentre collaboration is necessary to address the numerous unanswered questions pertaining to management of this disease. PMID:26142797

  17. Attentional guidance by relative features: Behavioral and electrophysiological evidence.

    PubMed

    Schönhammer, Josef G; Grubert, Anna; Kerzel, Dirk; Becker, Stefanie I

    2016-07-01

    Our ability to select task-relevant information from cluttered visual environments is widely believed to be due to our ability to tune attention to the particular elementary feature values of a sought-after target (e.g., red, orange, yellow). By contrast, recent findings showed that attention is often tuned to feature relationships, that is, features that the target has relative to irrelevant features in the context (e.g., redder, yellower). However, the evidence for such a relational account is so far exclusively based on behavioral measures that do not allow a safe inference about early perceptual processes. The present study provides a critical test of the relational account, by measuring an electrophysiological marker in the EEG of participants (N2pc) in response to briefly presented distractors (cues) that could either match the physical features of the target or its relative features. In a first experiment, the target color and nontarget color were kept constant across trials. In line with a relational account, we found that only cues with the same relative color as the target were attended, regardless of whether the cues had the same physical color as the target. In a second experiment, we demonstrate that attention is biased to the exact target feature value when the target is embedded in a randomly varying context. Taken together, these results provide the first electrophysiological evidence that attention can modulate early perceptual processes differently; in a context-dependent manner versus a context-independent manner, resulting in marked differences in the range of colors that can attract attention. PMID:26990008

  18. Central vs. peripheral neuraxial sympathetic control of porcine ventricular electrophysiology.

    PubMed

    Yamakawa, Kentaro; Howard-Quijano, Kimberly; Zhou, Wei; Rajendran, Pradeep; Yagishita, Daigo; Vaseghi, Marmar; Ajijola, Olujimi A; Armour, J Andrew; Shivkumar, Kalyanam; Ardell, Jeffrey L; Mahajan, Aman

    2016-03-01

    Sympathoexcitation is associated with ventricular arrhythmogenesis. The aim of this study was to determine the role of thoracic dorsal root afferent neural inputs to the spinal cord in modulating ventricular sympathetic control of normal heart electrophysiology. We hypothesize that dorsal root afferent input tonically modulates basal and evoked efferent sympathetic control of the heart. A 56-electrode sock placed on the epicardial ventricle in anesthetized Yorkshire pigs (n = 17) recorded electrophysiological function, as well as activation recovery interval (ARI) and dispersion in ARI, at baseline conditions and during stellate ganglion electrical stimulation. Measures were compared between intact states and sequential unilateral T1-T4 dorsal root transection (DRTx), ipsilateral ventral root transection (VRTx), and contralateral dorsal and ventral root transections (DVRTx). Left or right DRTx decreased global basal ARI [Lt.DRTx: 369 ± 12 to 319 ± 13 ms (P < 0.01) and Rt.DRTx: 388 ± 19 to 356 ± 15 ms (P < 0.01)]. Subsequent unilateral VRTx followed by contralateral DRx+VRTx induced no further change. In intact states, left and right stellate ganglion stimulation shortened ARIs (6 ± 2% vs. 17 ± 3%), while increasing dispersion (+139% vs. +88%). There was no difference in magnitude of ARI or dispersion change with stellate stimulation following spinal root transections. Interruption of thoracic spinal afferent signaling results in enhanced basal cardiac sympathoexcitability without diminishing the sympathetic response to stellate ganglion stimulation. This suggests spinal dorsal root transection releases spinal cord-mediated tonic inhibitory control of efferent sympathetic tone, while maintaining intrathoracic cardiocentric neural networks. PMID:26661096

  19. Correlation between muscle electrophysiology and strength after fibular nerve injury.

    PubMed

    Won, Yu Hui; Kim, Kang-Won; Choi, Jun Tak; Ko, Myoung-Hwan; Park, Sung-Hee; Seo, Jeong-Hwan

    2016-08-01

    Muscle strength measurement is important when evaluating the degree of impairment in patients with nerve injury. However, accurate and objective evaluation may be difficult in patients with severe pain or those who intentionally try to avoid full exertion. We investigated the usefulness of the affected-to-unaffected side electrophysiological parameter ratios as a measure of objective ankle dorsiflexion (ADF) strength in patients with unilateral fibular nerve injury (FNI). ADF strength was measured in patients with FNI via handheld dynamometer and manual muscle test (MMT). Fibular nerve compound muscle action potential (CMAP) amplitude and latency and ADF strength of the affected side were presented as ratios to the corresponding measurements of the unaffected side. We analysed the correlation of the CMAP ratio with the ADF strength ratio using a dynamometer and compared the CMAP ratios according to MMT grade. Fifty-two patients with FNI were enrolled. The mean CMAP latency ratio did not differ between MMT groups (p = 0.573). The CMAP amplitude ratio proportionally increased with the quantified ADF strength ratio via dynamometer increase (ρ = 0.790; p < 0.001), but the CMAP latency ratio and the quantified ADF strength ratio did not significantly correlate (ρ = 0.052; p = 0.713). The average CMAP amplitude ratio significantly differed between MMT groups (p < 0.001), and post hoc tests showed significant differences in all paired comparisons except of Fair and Good grades (p = 0.064). Electrophysiological parameter ratio, such as the affected-to-unaffected side CMAP amplitude ratio, might be sensitive parameters for ADF power estimation after FNI. PMID:27142447

  20. Consensus, contracts, and committees.

    PubMed

    Moreno, J D

    1991-08-01

    Following a brief account of the puzzle that ethics committees present for the Western Philosophical tradition, I will examine the possibility that social contract theory can contribute to a philosophical account of these committees. Passing through classical as well as contemporary theories, particularly Rawls' recent constructivist approach, I will argue that social contract theory places severe constraints on the authority that may legitimately be granted to ethics committees. This, I conclude, speaks more about the suitability of the theory to this level of analysis than about the ethics committee phenomenon itself. PMID:1895024

  1. 48 CFR 3017.204 - Contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Contracts. 3017.204... ACQUISITION REGULATION (HSAR) CONTRACT METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 3017.204 Contracts....

  2. 48 CFR 3017.204 - Contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Contracts. 3017.204 Section... ACQUISITION REGULATION (HSAR) CONTRACT METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 3017.204 Contracts....

  3. 48 CFR 3017.204 - Contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Contracts. 3017.204... ACQUISITION REGULATION (HSAR) CONTRACT METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 3017.204 Contracts....

  4. 48 CFR 3017.204 - Contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Contracts. 3017.204... ACQUISITION REGULATION (HSAR) CONTRACT METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options. 3017.204 Contracts....

  5. 48 CFR 16.307 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... commercial item) is contemplated. If the contract is with an educational institution, modify the clause by... AND CONTRACT TYPES TYPES OF CONTRACTS Cost-Reimbursement Contracts 16.307 Contract clauses. (a)(1)...

  6. 48 CFR 3017.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Contracts. 3017.204... ACQUISITION REGULATION (HSAR) CONTRACT METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options. 3017.204 Contracts....

  7. Cloudwave: Distributed Processing of “Big Data” from Electrophysiological Recordings for Epilepsy Clinical Research Using Hadoop

    PubMed Central

    Jayapandian, Catherine P.; Chen, Chien-Hung; Bozorgi, Alireza; Lhatoo, Samden D.; Zhang, Guo-Qiang; Sahoo, Satya S.

    2013-01-01

    Epilepsy is the most common serious neurological disorder affecting 50–60 million persons worldwide. Multi-modal electrophysiological data, such as electroencephalography (EEG) and electrocardiography (EKG), are central to effective patient care and clinical research in epilepsy. Electrophysiological data is an example of clinical “big data” consisting of more than 100 multi-channel signals with recordings from each patient generating 5–10GB of data. Current approaches to store and analyze signal data using standalone tools, such as Nihon Kohden neurology software, are inadequate to meet the growing volume of data and the need for supporting multi-center collaborative studies with real time and interactive access. We introduce the Cloudwave platform in this paper that features a Web-based intuitive signal analysis interface integrated with a Hadoop-based data processing module implemented on clinical data stored in a “private cloud”. Cloudwave has been developed as part of the National Institute of Neurological Disorders and Strokes (NINDS) funded multi-center Prevention and Risk Identification of SUDEP Mortality (PRISM) project. The Cloudwave visualization interface provides real-time rendering of multi-modal signals with “montages” for EEG feature characterization over 2TB of patient data generated at the Case University Hospital Epilepsy Monitoring Unit. Results from performance evaluation of the Cloudwave Hadoop data processing module demonstrate one order of magnitude improvement in performance over 77GB of patient data. (Cloudwave project: http://prism.case.edu/prism/index.php/Cloudwave) PMID:24551370

  8. Convergence of circuit dysfunction in ASD: a common bridge between diverse genetic and environmental risk factors and common clinical electrophysiology

    PubMed Central

    Port, Russell G.; Gandal, Michael J.; Roberts, Timothy P. L.; Siegel, Steven J.; Carlson, Gregory C.

    2014-01-01

    Most recent estimates indicate that 1 in 68 children are affected by an autism spectrum disorder (ASD). Though decades of research have uncovered much about these disorders, the pathological mechanism remains unknown. Hampering efforts is the seeming inability to integrate findings over the micro to macro scales of study, from changes in molecular, synaptic and cellular function to large-scale brain dysfunction impacting sensory, communicative, motor and cognitive activity. In this review, we describe how studies focusing on neuronal circuit function provide unique context for identifying common neurobiological disease mechanisms of ASD. We discuss how recent EEG and MEG studies in subjects with ASD have repeatedly shown alterations in ensemble population recordings (both in simple evoked related potential latencies and specific frequency subcomponents). Because these disease-associated electrophysiological abnormalities have been recapitulated in rodent models, studying circuit differences in these models may provide access to abnormal circuit function found in ASD. We then identify emerging in vivo and ex vivo techniques, focusing on how these assays can characterize circuit level dysfunction and determine if these abnormalities underlie abnormal clinical electrophysiology. Such circuit level study in animal models may help us understand how diverse genetic and environmental risks can produce a common set of EEG, MEG and anatomical abnormalities found in ASD. PMID:25538564

  9. Analytic theory of orbit contraction

    NASA Technical Reports Server (NTRS)

    Vinh, N. X.; Longuski, J. M.; Busemann, A.; Culp, R. D.

    1977-01-01

    The motion of a satellite in orbit, subject to atmospheric force and the motion of a reentry vehicle are governed by gravitational and aerodynamic forces. This suggests the derivation of a uniform set of equations applicable to both cases. For the case of satellite motion, by a proper transformation and by the method of averaging, a technique appropriate for long duration flight, the classical nonlinear differential equation describing the contraction of the major axis is derived. A rigorous analytic solution is used to integrate this equation with a high degree of accuracy, using Poincare's method of small parameters and Lagrange's expansion to explicitly express the major axis as a function of the eccentricity. The solution is uniformly valid for moderate and small eccentricities. For highly eccentric orbits, the asymptotic equation is derived directly from the general equation. Numerical solutions were generated to display the accuracy of the analytic theory.

  10. Acting Out Muscle Contraction.

    ERIC Educational Resources Information Center

    Hudson, Margaret

    2003-01-01

    Describes a science activity that can be implemented into anatomy and physiology courses that demonstrates the interactions between action and myosin, the roles of sodium and calcium ions in the regulation of contraction, and the functions of the plasma membrane and the sarcoplasmic reticulum. (YDS)

  11. Contracting for Audit Services.

    ERIC Educational Resources Information Center

    Heifetz, Harry S.

    1987-01-01

    The Single Audit Act of 1984 requires most school districts receiving over $25,000 in federal funds to undergo financial audits. This article highlights requirements for selecting certified public accountants to perform the audit and suggests factors to be considered before drafting a contract or letter of engagement. A sample letter is included.…

  12. Contracting with Teacher Partnerships.

    ERIC Educational Resources Information Center

    Shaten, Jessica; Kolderie, Ted

    This monograph describes the concept of school district contracts with teacher partnerships for educational services; taking the view of education as an industry, the document analyzes advantages, obstacles, and strategies of such a change. Section 1, "The Challenge," suggests that societal changes make an education industry outside the K-12…

  13. Copyright or Contract?

    ERIC Educational Resources Information Center

    Okerson, Ann

    1997-01-01

    Most authors and publishers of electronic information believe that current copyright law does not address technical capabilities or reader uses and have turned to contracts or licenses to define the rights of owners and users. Discusses copyrights, fair use, and licenses and highlights licensing's unresolved issues: use and users; archiving;…

  14. Contracting for directorships.

    PubMed

    Knapp, Donna K

    2013-05-01

    Hospitals are required to have a medical director of respiratory care as a condition of their participation in the Federal Medicare and Medicaid programs. This gives physicians opportunities to improve the quality of care for the patients in their community, to diversify income streams, and to assist hospitals to meet regulatory requirements for quality. The contracts for these positions are usually provided by the hospital, so it is imperative that physicians know how to protect their interests, what is expected of them, if they are being paid fairly, and that the contract is compliant with all regulatory issues. The directorship relationship with the hospital that provides designated health services and the "stand in the shoes" definition of direct compensation also gives physicians and physician practices guidance to determine if their group and individual physicians are compliant with Stark and antikickback regulations. This article guides physicians through the process of reviewing a contract for medical directorship or service line management services. Information on compensation in the directorship market can be found in at least two standard surveys. Duties and compensation vary among entities and frequently include incentive-based compensation for improving quality measures and operations. Directorships are evolving to service line management as more of the hospital's reimbursement is linked to clinical quality and patient satisfaction. This article does not offer legal advice, nor is it meant to be all inclusive. Physicians should consult a health-care attorney for any questions before signing any contract. PMID:23648911

  15. Employee contract issues for dermatologists.

    PubMed

    Brown, Christopher E; Indest, George F

    2013-12-01

    Employees and employers routinely face negotiating and preparing physician employment contracts. It is important for both sides to know and understand the basic information on what a comprehensive employment contract for a dermatologist should contain. There are various employment contract provisions from both the employee's perspective and the employer's perspective that must be considered when preparing physician employment contracts. This article provides basic advice and recommendations on requirements that should be included in such contracts. It suggests legal pitfalls that can be avoided through various contract clauses. PMID:24800433

  16. The formal treatment contract in the inpatient management of borderline personality disorder.

    PubMed

    Miller, L J

    1990-09-01

    Formal, written contracts between the patient and the treatment team have been shown to be useful in the inpatient management of borderline personality disorder by fostering a therapeutic alliance, containing dangerous behavior, and protecting the integrity of the treatment. The author discusses the advantages and disadvantages of such contracts and points out several common contractual errors, including making a contract too restrictive, allowing the contract to substitute for psychotherapy, and using the contract as a means of defense or punishment. She provides 12 guidelines, for formulating successful contracts, beginning with the need to clearly state the purpose of the treatment plan mutually agreed on by patient and staff. PMID:2210708

  17. Payload missions integration

    NASA Technical Reports Server (NTRS)

    Mitchell, R. A. K.

    1983-01-01

    Highlights of the Payload Missions Integration Contract (PMIC) are summarized. Spacelab Missions no. 1 to 3, OSTA partial payloads, Astro-1 Mission, premission definition, and mission peculiar equipment support structure are addressed.

  18. Auditory Cortical Maturation in a Child with Cochlear Implant: Analysis of Electrophysiological and Behavioral Measures

    PubMed Central

    Silva, Liliane Aparecida Fagundes; Couto, Maria Inês Vieira; Tsuji, Robinson Koji; Bento, Ricardo Ferreira; de Carvalho, Ana Claudia Martinho; Matas, Carla Gentile

    2015-01-01

    The purpose of this study was to longitudinally assess the behavioral and electrophysiological hearing changes of a girl inserted in a CI program, who had bilateral profound sensorineural hearing loss and underwent surgery of cochlear implantation with electrode activation at 21 months of age. She was evaluated using the P1 component of Long Latency Auditory Evoked Potential (LLAEP); speech perception tests of the Glendonald Auditory Screening Procedure (GASP); Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS); and Meaningful Use of Speech Scales (MUSS). The study was conducted prior to activation and after three, nine, and 18 months of cochlear implant activation. The results of the LLAEP were compared with data from a hearing child matched by gender and chronological age. The results of the LLAEP of the child with cochlear implant showed gradual decrease in latency of the P1 component after auditory stimulation (172 ms–134 ms). In the GASP, IT-MAIS, and MUSS, gradual development of listening skills and oral language was observed. The values of the LLAEP of the hearing child were expected for chronological age (132 ms–128 ms). The use of different clinical instruments allow a better understanding of the auditory habilitation and rehabilitation process via CI. PMID:26881163

  19. Materials for Multifunctional Balloon Catheters With Capabilities in Cardiac Electrophysiological Mapping and Ablation Therapy

    PubMed Central

    Kim, Dae-Hyeong; Lu, Nanshu; Ghaffari, Roozbeh; Kim, Yun-Soung; Lee, Stephen P.; Xu, Lizhi; Wu, Jian; Kim, Rak-Hwan; Song, Jizhou; Liu, Zhuangjian; Viventi, Jonathan; de Graff, Bassel; Elolampi, Brian; Mansour, Moussa; Slepian, Marvin J.; Hwang, Sukwon; Moss, Joshua D.; Won, Sang-Min; Huang, Younggang; Litt, Brian; Rogers, John A.

    2011-01-01

    Development of advanced surgical tools for minimally invasive procedures represents an activity of central importance to improvements in human health. A key materials challenge is in the realization of bio-compatible interfaces between the classes of semiconductor and sensor technologies that might be most useful in this context and the soft, curvilinear surfaces of the body. This paper describes a solution based on biocompatible materials and devices that integrate directly with the thin elastic membranes of otherwise conventional balloon catheters, to provide multimodal functionality suitable for clinical use. We present sensors for measuring temperature, flow, tactile, optical and electrophysiological data, together with radio frequency (RF) electrodes for controlled, local ablation of tissue. These components connect together in arrayed layouts designed to decouple their operation from large strain deformations associated with deployment and repeated inflation/deflation. Use of such ‘instrumented’ balloon catheter devices in live animal models and in vitro tests illustrates their operation in cardiac ablation therapy. These concepts have the potential for application in surgical systems of the future, not only those based on catheters but also on other platforms, such as surgical gloves. PMID:21378969

  20. A scalable neuroinformatics data flow for electrophysiological signals using MapReduce.

    PubMed

    Jayapandian, Catherine; Wei, Annan; Ramesh, Priya; Zonjy, Bilal; Lhatoo, Samden D; Loparo, Kenneth; Zhang, Guo-Qiang; Sahoo, Satya S

    2015-01-01

    Data-driven neuroscience research is providing new insights in progression of neurological disorders and supporting the development of improved treatment approaches. However, the volume, velocity, and variety of neuroscience data generated from sophisticated recording instruments and acquisition methods have exacerbated the limited scalability of existing neuroinformatics tools. This makes it difficult for neuroscience researchers to effectively leverage the growing multi-modal neuroscience data to advance research in serious neurological disorders, such as epilepsy. We describe the development of the Cloudwave data flow that uses new data partitioning techniques to store and analyze electrophysiological signal in distributed computing infrastructure. The Cloudwave data flow uses MapReduce parallel programming algorithm to implement an integrated signal data processing pipeline that scales with large volume of data generated at high velocity. Using an epilepsy domain ontology together with an epilepsy focused extensible data representation format called Cloudwave Signal Format (CSF), the data flow addresses the challenge of data heterogeneity and is interoperable with existing neuroinformatics data representation formats, such as HDF5. The scalability of the Cloudwave data flow is evaluated using a 30-node cluster installed with the open source Hadoop software stack. The results demonstrate that the Cloudwave data flow can process increasing volume of signal data by leveraging Hadoop Data Nodes to reduce the total data processing time. The Cloudwave data flow is a template for developing highly scalable neuroscience data processing pipelines using MapReduce algorithms to support a variety of user applications. PMID:25852536

  1. Auditory Cortical Maturation in a Child with Cochlear Implant: Analysis of Electrophysiological and Behavioral Measures.

    PubMed

    Silva, Liliane Aparecida Fagundes; Couto, Maria Inês Vieira; Tsuji, Robinson Koji; Bento, Ricardo Ferreira; de Carvalho, Ana Claudia Martinho; Matas, Carla Gentile

    2015-01-01

    The purpose of this study was to longitudinally assess the behavioral and electrophysiological hearing changes of a girl inserted in a CI program, who had bilateral profound sensorineural hearing loss and underwent surgery of cochlear implantation with electrode activation at 21 months of age. She was evaluated using the P1 component of Long Latency Auditory Evoked Potential (LLAEP); speech perception tests of the Glendonald Auditory Screening Procedure (GASP); Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS); and Meaningful Use of Speech Scales (MUSS). The study was conducted prior to activation and after three, nine, and 18 months of cochlear implant activation. The results of the LLAEP were compared with data from a hearing child matched by gender and chronological age. The results of the LLAEP of the child with cochlear implant showed gradual decrease in latency of the P1 component after auditory stimulation (172 ms-134 ms). In the GASP, IT-MAIS, and MUSS, gradual development of listening skills and oral language was observed. The values of the LLAEP of the hearing child were expected for chronological age (132 ms-128 ms). The use of different clinical instruments allow a better understanding of the auditory habilitation and rehabilitation process via CI. PMID:26881163

  2. Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices

    PubMed Central

    Rouach, Nathalie

    2012-01-01

    Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents. PMID:23222635

  3. A scalable neuroinformatics data flow for electrophysiological signals using MapReduce

    PubMed Central

    Jayapandian, Catherine; Wei, Annan; Ramesh, Priya; Zonjy, Bilal; Lhatoo, Samden D.; Loparo, Kenneth; Zhang, Guo-Qiang; Sahoo, Satya S.

    2015-01-01

    Data-driven neuroscience research is providing new insights in progression of neurological disorders and supporting the development of improved treatment approaches. However, the volume, velocity, and variety of neuroscience data generated from sophisticated recording instruments and acquisition methods have exacerbated the limited scalability of existing neuroinformatics tools. This makes it difficult for neuroscience researchers to effectively leverage the growing multi-modal neuroscience data to advance research in serious neurological disorders, such as epilepsy. We describe the development of the Cloudwave data flow that uses new data partitioning techniques to store and analyze electrophysiological signal in distributed computing infrastructure. The Cloudwave data flow uses MapReduce parallel programming algorithm to implement an integrated signal data processing pipeline that scales with large volume of data generated at high velocity. Using an epilepsy domain ontology together with an epilepsy focused extensible data representation format called Cloudwave Signal Format (CSF), the data flow addresses the challenge of data heterogeneity and is interoperable with existing neuroinformatics data representation formats, such as HDF5. The scalability of the Cloudwave data flow is evaluated using a 30-node cluster installed with the open source Hadoop software stack. The results demonstrate that the Cloudwave data flow can process increasing volume of signal data by leveraging Hadoop Data Nodes to reduce the total data processing time. The Cloudwave data flow is a template for developing highly scalable neuroscience data processing pipelines using MapReduce algorithms to support a variety of user applications. PMID:25852536

  4. Closed-Loop, Multichannel Experimentation Using the Open-Source NeuroRighter Electrophysiology Platform

    PubMed Central

    Newman, Jonathan P.; Zeller-Townson, Riley; Fong, Ming-Fai; Arcot Desai, Sharanya; Gross, Robert E.; Potter, Steve M.

    2013-01-01

    Single neuron feedback control techniques, such as voltage clamp and dynamic clamp, have enabled numerous advances in our understanding of ion channels, electrochemical signaling, and neural dynamics. Although commercially available multichannel recording and stimulation systems are commonly used for studying neural processing at the network level, they provide little native support for real-time feedback. We developed the open-source NeuroRighter multichannel electrophysiology hardware and software platform for closed-loop multichannel control with a focus on accessibility and low cost. NeuroRighter allows 64 channels of stimulation and recording for around US $10,000, along with the ability to integrate with other software and hardware. Here, we present substantial enhancements to the NeuroRighter platform, including a redesigned desktop application, a new stimulation subsystem allowing arbitrary stimulation patterns, low-latency data servers for accessing data streams, and a new application programming interface (API) for creating closed-loop protocols that can be inserted into NeuroRighter as plugin programs. This greatly simplifies the design of sophisticated real-time experiments without sacrificing the power and speed of a compiled programming language. Here we present a detailed description of NeuroRighter as a stand-alone application, its plugin API, and an extensive set of case studies that highlight the system’s abilities for conducting closed-loop, multichannel interfacing experiments. PMID:23346047

  5. Electrophysiology of Hypothalamic Magnocellular Neurons In vitro: A Rhythmic Drive in Organotypic Cultures and Acute Slices

    PubMed Central

    Israel, Jean-Marc; Oliet, Stéphane H.; Ciofi, Philippe

    2016-01-01

    Hypothalamic neurohormones are released in a pulsatile manner. The mechanisms of this pulsatility remain poorly understood and several hypotheses are available, depending upon the neuroendocrine system considered. Among these systems, hypothalamo-neurohypophyseal magnocellular neurons have been early-considered models, as they typically display an electrical activity consisting of bursts of action potentials that is optimal for the release of boluses of the neurohormones oxytocin and vasopressin. The cellular mechanisms underlying this bursting behavior have been studied in vitro, using either acute slices of the adult hypothalamus, or organotypic cultures of neonatal hypothalamic tissue. We have recently proposed, from experiments in organotypic cultures, that specific central pattern generator networks, upstream of magnocellular neurons, determine their bursting activity. Here, we have tested whether a similar hypothesis can be derived from in vitro experiments in acute slices of the adult hypothalamus. To this aim we have screened our electrophysiological recordings of the magnocellular neurons, previously obtained from acute slices, with an analysis of autocorrelation of action potentials to detect a rhythmic drive as we recently did for organotypic cultures. This confirmed that the bursting behavior of magnocellular neurons is governed by central pattern generator networks whose rhythmic drive, and thus probably integrity, is however less satisfactorily preserved in the acute slices from adult brains. PMID:27065780

  6. 48 CFR 35.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., performance objectives, and specifications for the work can be defined will largely determine the type of contract employed. The contract type must be selected to fit the work required. (c) Because the absence of...-reimbursement contracts is usually appropriate (see subpart 16.3). The nature of development work often...

  7. 48 CFR 1335.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 1335.006 Contracting methods and... is exempt from the requirements of 15 CFR part 27 and does not require Institutional Review Board... research involving human subjects to be carried out in performance of the award is exempt from 15 CFR...

  8. 48 CFR 1335.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 1335.006 Contracting methods and... is exempt from the requirements of 15 CFR part 27 and does not require Institutional Review Board... research involving human subjects to be carried out in performance of the award is exempt from 15 CFR...

  9. Electrophysiological and behavioral phenotype of insulin receptor defective mice

    PubMed Central

    Das, P.; Parsons, A.D.; Scarborough, J.; Hoffman, J.; Wilson, J.; Thompson, R.N.; Overton, J.M.; Fadool, D.A.

    2009-01-01

    The olfactory bulb expresses one of the highest levels of insulin found in the brain. A high level of expression of the concomitant insulin receptor (IR) kinase is also retained in this brain region, even in the adult. We have previously demonstrated in a heterologous system that insulin modulates the voltage-dependent potassium channel, Kv1.3, through tyrosine phosphorylation of three key residues in the amino and carboxyl terminus of the channel protein. Phosphorylation also induces current suppression of the Kv1.3-contributed current in cultured olfactory bulb neurons (OBNs) of rodents. In order to explore the behavioral importance of this kinase-induced modulation of the channel for the olfactory ability of the animal, mice with a targeted-gene deletion of the insulin receptor were electrophysiologically and behaviorally characterized. Mice heterozygous for the insulin receptor kinase (IR+/−) gene performed the same as wild-type (+/+) mice when challenged with a traditional, non-learning-based task to test gross anosmia. There was also no significant difference across the two genotypes in tests designed to measure exploratory behavior or in a battery of systems physiology experiments designed to assess metabolic energy usage (locomotion, ingestive behaviors, weight, oxygen consumption, and respiratory quotient). Object memory recognition tests suggest that IR+/− mice have an impairment in recognition of familiarized objects; IR+/− mice demonstrate poor performance for both short-term (1 h) and long-term (24 h) memory tests in comparison to that of wild-type mice. Electrophysiological experiments indicate that mitral cell neurons cultured from both heterozygous and homozygous-null mice (IR+/− and IR−/−) have an decreased peak current amplitude compared with that recorded for wild-type (+/+) animals matched for days in vitro (DIV). These data indicate that the loss of one allele of the IR kinase gene modifies the electrical phenotype of the mitral

  10. Active sodium transport and the electrophysiology of rabbit colon.

    PubMed

    Schultz, S G; Frizzell, R A; Nellans, H N

    1977-05-12

    The electrophysiologic properties of rabbit colonic epithelial cells were investigated employing microelectrode techniques. Under open-circuit conditions, the transepithelial electrical potential difference (PD) averaged 20 mV, serosa positive, and the intracellular electrical potential (psimc) averaged -32 mV, cell interior negative with respect to the mucosal solution; under short-circuit conditions, psimc averaged -46 mV. The addition of amiloride to the mucosal solution abolishes the transepithelial PD and active Na transport, and psimc is hyperpolarized to an average value of -53 mV. These results indicate that Na entry into the mucosal cell is a conductive process which, normally, depolarized psimc. The data obtained were interpreted using a double-membrane equivalent electrical circuit model of the "active Na transport pathway" involving two voltage-independent electromotive forces (emf's) and two voltage-independent resistances arrayed in series. Our observations are consistent with the notions that: (a) The emf's and resistances across the mucosal and baso-lateral membranes are determined predominantly by the emf (64 mV) and resistance of the Na entry process and the emf (53 mV) and resistance of the process responsible for active Na extrusion across the baso-lateral membranes: that is, the electrophysiological properties of the cell appear to be determined solely by the properties and processes responsible for transcellular active Na transport. The emf of the Na entry process is consistent with the notion that the Na activity in the intracellular transport pool is approximately one-tenth that in the mucosal solution or about 14 mM. (b) In the presence of amiloride, the transcellular conductance is essentially abolished and the total tissue conductance is the result of ionic diffusion through paracellular pathways. (c) The negative intracellular potential (with respect to the mucosal solution) is due primarily to the presence of a low resistance

  11. 48 CFR 3443.107 - Contract clause.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Contract clause. 3443.107... CONTRACT MANAGEMENT CONTRACT MODIFICATIONS General 3443.107 Contract clause. The contracting officer must... cost-reimbursement contracts in which it will be essential for the contracting officer to be...

  12. 48 CFR 16.302 - Cost contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Cost contracts. 16.302... AND CONTRACT TYPES TYPES OF CONTRACTS Cost-Reimbursement Contracts 16.302 Cost contracts. (a) Description. A cost contract is a cost-reimbursement contract in which the contractor receives no fee....

  13. 48 CFR 937.7040 - Contract clauses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CONTRACTING SERVICE CONTRACTING Protective Services Contracting 937.7040 Contract clauses. The contracting... services” in all protective services solicitations and contracts involving DOE-owned facilities requiring... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Contract clauses....

  14. Utility Energy Services Contracts Guide

    SciTech Connect

    2013-09-01

    The UESC Guide is a compilation of samples and templates developed as a resource to help contracting officers implement task orders for UESCs under existing U.S. General Services Administration areawide contracts.

  15. A wearable chemical-electrophysiological hybrid biosensing system for real-time health and fitness monitoring.

    PubMed

    Imani, Somayeh; Bandodkar, Amay J; Mohan, A M Vinu; Kumar, Rajan; Yu, Shengfei; Wang, Joseph; Mercier, Patrick P

    2016-01-01

    Flexible, wearable sensing devices can yield important information about the underlying physiology of a human subject for applications in real-time health and fitness monitoring. Despite significant progress in the fabrication of flexible biosensors that naturally comply with the epidermis, most designs measure only a small number of physical or electrophysiological parameters, and neglect the rich chemical information available from biomarkers. Here, we introduce a skin-worn wearable hybrid sensing system that offers simultaneous real-time monitoring of a biochemical (lactate) and an electrophysiological signal (electrocardiogram), for more comprehensive fitness monitoring than from physical or electrophysiological sensors alone. The two sensing modalities, comprising a three-electrode amperometric lactate biosensor and a bipolar electrocardiogram sensor, are co-fabricated on a flexible substrate and mounted on the skin. Human experiments reveal that physiochemistry and electrophysiology can be measured simultaneously with negligible cross-talk, enabling a new class of hybrid sensing devices. PMID:27212140

  16. A wearable chemical–electrophysiological hybrid biosensing system for real-time health and fitness monitoring

    PubMed Central

    Imani, Somayeh; Bandodkar, Amay J.; Mohan, A. M. Vinu; Kumar, Rajan; Yu, Shengfei; Wang, Joseph; Mercier, Patrick P.

    2016-01-01

    Flexible, wearable sensing devices can yield important information about the underlying physiology of a human subject for applications in real-time health and fitness monitoring. Despite significant progress in the fabrication of flexible biosensors that naturally comply with the epidermis, most designs measure only a small number of physical or electrophysiological parameters, and neglect the rich chemical information available from biomarkers. Here, we introduce a skin-worn wearable hybrid sensing system that offers simultaneous real-time monitoring of a biochemical (lactate) and an electrophysiological signal (electrocardiogram), for more comprehensive fitness monitoring than from physical or electrophysiological sensors alone. The two sensing modalities, comprising a three-electrode amperometric lactate biosensor and a bipolar electrocardiogram sensor, are co-fabricated on a flexible substrate and mounted on the skin. Human experiments reveal that physiochemistry and electrophysiology can be measured simultaneously with negligible cross-talk, enabling a new class of hybrid sensing devices. PMID:27212140

  17. Retinal Electrophysiology Is a Viable Preclinical Biomarker for Drug Penetrance into the Central Nervous System

    PubMed Central

    Charng, Jason; He, Zheng; Vingrys, Algis J.; Fish, Rebecca L.; Gurrell, Rachel; Bui, Bang V.; Nguyen, Christine T.

    2016-01-01

    Objective. To examine whether retinal electrophysiology is a useful surrogate marker of drug penetrance into the central nervous system (CNS). Materials and Methods. Brain and retinal electrophysiology were assessed with full-field visually evoked potentials and electroretinograms in conscious and anaesthetised rats following systemic or local administrations of centrally penetrant (muscimol) or nonpenetrant (isoguvacine) compounds. Results. Local injections into the eye/brain bypassed the blood neural barriers and produced changes in retinal/brain responses for both drugs. In conscious animals, systemic administration of muscimol resulted in retinal and brain biopotential changes, whereas systemic delivery of isoguvacine did not. General anaesthesia confounded these outcomes. Conclusions. Retinal electrophysiology, when recorded in conscious animals, shows promise as a viable biomarker of drug penetration into the CNS. In contrast, when conducted under anaesthetised conditions confounds can be induced in both cortical and retinal electrophysiological recordings. PMID:27239335

  18. Differences in Left Versus Right Ventricular Electrophysiological Properties in Cardiac Dysfunction and Arrhythmogenesis

    PubMed Central

    Molina, Cristina E; Heijman, Jordi; Dobrev, Dobromir

    2016-01-01

    A wide range of ion channels, transporters, signaling pathways and tissue structure at a microscopic and macroscopic scale regulate the electrophysiological activity of the heart. Each region of the heart has optimised these properties based on its specific role during the cardiac cycle, leading to well-established differences in electrophysiology, Ca2+ handling and tissue structure between atria and ventricles and between different layers of the ventricular wall. Similarly, the right ventricle (RV) and left ventricle (LV) have different embryological, structural, metabolic and electrophysiological features, but whether interventricular differences promote differential remodeling leading to arrhythmias is not well understood. In this article, we will summarise the available data on intrinsic differences between LV and RV electrophysiology and indicate how these differences affect cardiac function. Furthermore, we will discuss the differential remodeling of both chambers in pathological conditions and its potential impact on arrhythmogenesis. PMID:27403288

  19. Contracts for dispatchable power

    SciTech Connect

    Kahn, E.P.; Stoft, S.; Marnay, C.; Berman, D.

    1990-10-01

    Competitive bidding for electric power is maturing. Increasing numbers of utilities are soliciting proposals from private suppliers. The amount of capacity being sought is increasing, and potential suppliers appear to be abundant. Analysis of these developments still remains limited. Evidence on the behavior of this market is scarce and sketchy. The underlying economic principles that are shaping the market have not clearly been articulated. In this report we examine the economics of competitive bidding both empirically and analytically. Previous study of this market has focused on the evaluation criteria specified in Requests for Proposals (RFPs), and highly aggregated summary statistics on participation and results. We continue the examination of RFPs, but also survey the details of long term contracts that have emerged from competitive bidding. Contracts provide a new level of specific detail that has not been previously available. 68 refs., 13 figs., 25 tabs.

  20. Dupuytren's Contracture: Fibroblast Contraction?

    PubMed Central

    Gabbiani, Giulio; Majno, Guido

    1972-01-01

    In 6 cases of Dupuytren's disease and 1 of Ledderhose's disease, the nodules of the palmar and plantar aponeurosis were examined by light and electron microscopy. The cells composing these nodules, presumably fibroblasts, showed three significant ultrastructural features: (1) a fibrillar system similar to that of smooth muscle cells; (2) nuclear deformations such as are found in contracted cells, the severest being recognizable by light microscopy (cross-banded nuclei); (3) cell-to-cell and cell-to-stroma attachments. Based on these data and on recent information about the biology of the fibroblasts, it is suggested that these cells are fibroblasts that have modulated into contractile cells (myofibroblasts), and that their contraction plays a role in the pathogenesis of the contracture observed clinically. ImagesFig 10Fig 5Fig 11Fig 6 and 7Fig 8Fig 1Fig 2Fig 9Fig 3Fig 4 PMID:5009249

  1. Russian Contract Procurement Document

    SciTech Connect

    Tobin, J G

    2010-03-29

    This contract supports the enhancement of physical protection or nuclear material control and accounting systems at institutes or enterprises of the newly independent states under the material protection control and accounting (MPC&A) program. The contract is entered into pursuant to the MPC&A Program, a gratuitous technical assistance program, in accordance with the bilateral Agreements between the Russian Federation and the United States of America concerning the Safe and Secure Transportation, Storage and Destruction of Weapons and the Prevention of Weapons Proliferation of June 1992, as extended and amended by Protocol signed of June 1999, Agreement between the Government of the Russian Federation regarding Cooperation in the Area of Nuclear Materials Physical Protection, Control and Accounting of October 1999 and the Russian Federation law of May 1999 on the taxation exemption of gratuitous technical assistance with Russian Federation under registration No.DOE001000.

  2. The Unwritten Contract

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Hosted by former STS-1 Astronaut Bob Crippen, this video highlights the Space Shuttle program team's commitment to quality assurance as being the unwritten contract all workers in the shuttle program have with the flight crews: To keep them and the whole Space Transportation System safe. The video is presented by the Marshall Space Flight Center's Safety, Reliability, Maintainability, and Quality Assurance Office (SRM&QA).

  3. Elements of gas contracts

    SciTech Connect

    O`Neal, J.

    1995-12-01

    The gas marketing scene has taken on a new look from the days of the {open_quotes}Long Term{close_quotes} or {open_quotes}Life of Lease{close_quotes} Contracts. In the past natural gas was of ten sold direct from the wellhead or a producer-owned facility to a pipeline company at a flat rate price and the only parties involved were producer or seller and buyer. Today, the parties involved in the marketing process might include a gathering entity to gather gas at a central point and provide gathering, compression and/or dehydration services; multiple pipeline companies for transportation; sales representatives or marketing brokers to negotiate a sale of the available gas on a monthly basis; and purchasers or end users. New terms have also been introduced in the process such as: {open_quotes}LDC{close_quotes} (local distribution company), {open_quotes}FERC Order 636{close_quotes}, {open_quotes}Price Delivered-to-Pipeline{close_quotes} and the various {open_quotes}levels of Service{close_quotes} under Gas Sales and Purchase Agreements. Four common levels of service are: {open_quotes}Firm{close_quotes}, {open_quotes}Baseload{close_quotes}, {open_quotes}Swing{close_quotes} and {open_quotes}Baseload/Operational{close_quotes}. It is evident that current marketing plans often require a separate contract for each service or commitment. Contract contents vary greatly, but most contain the following elements.

  4. Health Contract in the Classroom

    ERIC Educational Resources Information Center

    Haber, David

    2007-01-01

    A health contract is a technique used by health professionals to help clients achieve a health goal. This article describes a course, "Changing Health Behaviors," in which a health contract strategy is taught and practiced with older adults. The health contract can also be included as a smaller educational component within a gerontology course…

  5. How Learning Contracts Motivate Students

    ERIC Educational Resources Information Center

    Greenwood, Scott C.; McCabe, Patrick P.

    2008-01-01

    In this article, the authors discuss how learning contracts can motivate students. "A learning contract is simply a written agreement between teacher and learner in which the learner undertakes to complete mutually agreed upon tasks in a specified amount of time on his or her own initiative" (Greenwood, 2003, p.1). Contracts are designed to…

  6. 48 CFR 1842.7202 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACT MANAGEMENT CONTRACT ADMINISTRATION AND AUDIT SERVICES NASA Contractor Financial Management... Contractor Financial Management Reporting, in solicitations and contracts when any of the NASA Form...

  7. 48 CFR 1842.7202 - Contract clause.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CONTRACT MANAGEMENT CONTRACT ADMINISTRATION AND AUDIT SERVICES NASA Contractor Financial Management... Contractor Financial Management Reporting, in solicitations and contracts when any of the NASA Form...

  8. Electrophysiological characterisation of motor and sensory tracts in patients with hereditary spastic paraplegia (HSP)

    PubMed Central

    2013-01-01

    Background Hereditary spastic paraplegias (HSPs) are characterised by lower limb spasticity due to degeneration of the corticospinal tract. We set out for an electrophysiological characterisation of motor and sensory tracts in patients with HSP. Methods We clinically and electrophysiologically examined a cohort of 128 patients with genetically confirmed or clinically probable HSP. Motor evoked potentials (MEPs) to arms and legs, somato-sensory evoked potentials of median and tibial nerves, and nerve conduction studies of tibial, ulnar, sural, and radial nerves were assessed. Results Whereas all patients showed clinical signs of spastic paraparesis, MEPs were normal in 27% of patients and revealed a broad spectrum with axonal or demyelinating features in the others. This heterogeneity can at least in part be explained by different underlying genotypes, hinting for distinct pathomechanisms in HSP subtypes. In the largest subgroup, SPG4, an axonal type of damage was evident. Comprehensive electrophysiological testing disclosed a more widespread affection of long fibre tracts involving peripheral nerves and the sensory system in 40%, respectively. Electrophysiological abnormalities correlated with the severity of clinical symptoms. Conclusions Whereas HSP is primarily considered as an upper motoneuron disorder, our data suggest a more widespread affection of motor and sensory tracts in the central and peripheral nervous system as a common finding in HSP. The distribution patterns of electrophysiological abnormalities were associated with distinct HSP genotypes and could reflect different underlying pathomechanisms. Electrophysiological measures are independent of symptomatic treatment and may therefore serve as a reliable biomarker in upcoming HSP trials. PMID:24107482

  9. Modelling tissue electrophysiology with multiple cell types: applications of the extended bidomain framework.

    PubMed

    Corrias, Alberto; Pathmanathan, Pras; Gavaghan, David J; Buist, Martin L

    2012-02-01

    The bidomain framework has been extensively used to model tissue electrophysiology in a variety of applications. One limitation of the bidomain model is that it describes the activity of only one cell type interacting with the extracellular space. If more than one cell type contributes to the tissue electrophysiology, then the bidomain model is not sufficient. Recently, evidence has suggested that this is the case for at least two important applications: cardiac and gastrointestinal tissue electrophysiology. In the heart, fibroblasts ubiquitously interact with myocytes and are believed to play an important role in the organ electrophysiology. Along the GI tract, interstitial cells of Cajal (ICC) generate electrical waves that are passed on to surrounding smooth muscle cells (SMC), which are interconnected with the ICC and with each other. Because of the contribution of more than one cell type to the overall organ electrophysiology, investigators in different fields have independently proposed similar extensions of the bidomain model to incorporate multiple cell types and tested it on simplified geometries. In this paper, we provide a general derivation of such an extended bidomain framework applicable to any tissue and provide a generic and efficient implementation applicable to any geometry. Proof-of-concept results of tissue electrophysiology on realistic 3D organ geometries using the extended bidomain framework are presented for the heart and the stomach. PMID:22222297

  10. Multifocal motor neuropathy: correlation of nerve ultrasound, electrophysiological, and clinical findings.

    PubMed

    Kerasnoudis, Antonios; Pitarokoili, Kalliopi; Behrendt, Volker; Gold, Ralf; Yoon, Min-Suk

    2014-06-01

    We present nerve ultrasound findings in multifocal motor neuropathy (MMN) and examine their correlation with electrophysiology and functional disability. Eighty healthy controls and 12 MMN patients underwent clinical, sonographic, and electrophysiological evaluation a mean of 3.5 years (standard deviation [SD] ± 2.1) after disease onset. Nerve ultrasound revealed significantly higher cross-sectional area (CSA) values of the median (forearm, p < 0.001), ulnar (p < 0.001), and tibial nerve (ankle, p < 0.001) when compared with controls. Electroneurography documented signs of significantly lower values of the motor conduction velocity and compound muscle action potentials (cMAPs) in the upper arm nerves (median, ulnar, radial, p < 0.001). A significant correlation between sonographic and electrophysiological findings in the MMN group was found only between cMAP and CSA of the median nerve at the upper arm (r = 0.851, p < 0.001). Neither nerve sonography nor electrophysiology correlated with functional disability. MMN seems to show inhomogeneous CSA enlargement in various peripheral nerves, with weak correlation to electrophysiological findings. Neither nerve sonography nor electrophysiology correlated with functional disability. Multicentre, prospective studies are required to prove the applicability and diagnostic values of these findings. PMID:24862982

  11. Distinct morphological and electrophysiological properties of an elk prion peptide.

    PubMed

    Glaves, John Paul; Gorski, Przemek A; Alier, Kwai; Ma, Li; Renault, Ludovic; Primeau, Joseph O; Jhamandas, Jack H; Young, Howard S

    2013-02-01

    A key event in prion diseases is the conversion of the prion protein (PrP) from its native α-helical conformation to a misfolded, β-sheet rich conformation. Thus, preventing or reversing PrP misfolding could provide a means to disrupt prion disease progression and transmission. However, determining the structure of misfolded PrP has been notoriously difficult due to its inherent heterogeneity and aggregation behavior. For these reasons, simplified peptide fragments have been used as models that recapitulate characteristics of full-length PrP, such as amyloid-like aggregation and fibril formation, and in vitro toxicity. We provide a biochemical and structural comparison of PrP(127-147) peptides from elk, bovine and hamster using electrophysiology, electron microscopy and fluorescence. Our results demonstrate that the PrP(127-147) peptides adopt distinct populations of fibril structures. In addition, the elk PrP(127-147) peptide is unique in its ability to enhance Thioflavin T fluorescence and its ability to modulate neuronal ion channel conductances. PMID:23262353

  12. Interventional Electrophysiology in Children: A Single-Center Experience

    PubMed Central

    Mosaed, Pasha; Dalili, Mohammad; Emkanjoo, Zahra

    2012-01-01

    Objective Ablation techniques of cardiac arrhythmia in children have significantly progressed in the past decade; however, the number of pediatric ablations is still significantly lower than that in adults. Accordingly, there is less information regarding the success rate and complications in this age group. Methods All pediatric ablations conducted between March 2005 and February 2011 at Rajaie Heart Center were studied. Abolishing the arrhythmia source by the end of procedure was considered as success. Recurrences before hospital discharge and those thereafter were named early recurrence and late recurrence, respectively. Findings A total of 125 catheter ablations were performed for 112 patients. Of them 118 (94.4%) procedures were successful. The success rate was significantly higher in the patients with atrioventricular nodal reentry tachycardia (AVNRT). Of 105 patients who continued follow-up program, 7 (6.7%) cases experienced recurrence; the recurrence rate was inversely dependent on the patients’ body size (P-value <0.05). There was no mortality. Five cases were complicated during or early after the procedure, all the complications were cured completely. Conclusion Therapeutic electrophysiology in children is an effective and relatively low-risk method. The recurrence and complication rates are similar to those reported in adults. Considering our results and the previous reports, pediatric patients with serious arrhythmia should not be deprived from ablation and should not be exposed to long-term toxic drugs. PMID:23399953

  13. Electrophysiological action of bepridil on atrioventricular accessory pathways.

    PubMed Central

    Touboul, P; Atallah, G; Kirkorian, G; Lavaud, P; Kieny, J R; Mathieu, M P; Dellinger, A

    1987-01-01

    The electrophysiologic properties of bepridil, a calcium channel blocker with additional effects on fast response tissues, were investigated in 10 patients with atrioventricular accessory pathways. Seven patients had Wolff-Parkinson-White syndrome, and three had concealed atrioventricular pre-excitation. A dose of 4 mg/kg was administered intravenously over five minutes. Bepridil increased the AH interval and the functional refractory period of the atrioventricular node. The effective refractory periods of the right atrium and right ventricle were also increased. Bepridil prolonged refractoriness in the accessory pathway both in the anterograde and retrograde direction. After bepridil administration it was impossible to induce reciprocating tachycardia electrically in two patients because of conduction block in the normal pathway. On the other hand, the zone of tachycardia was often increased after bepridil. Nevertheless, the heart rate during tachycardia was slowed by depression of conduction in both the normal and accessory pathways. The findings of this study provide a basis for the antiarrhythmic action of bepridil in patients with atrioventricular accessory pathways. PMID:3499924

  14. The Electrophysiological Underpinnings of Processing Gender Stereotypes in Language

    PubMed Central

    Siyanova-Chanturia, Anna; Pesciarelli, Francesca; Cacciari, Cristina

    2012-01-01

    Despite the widely documented influence of gender stereotypes on social behaviour, little is known about the electrophysiological substrates engaged in the processing of such information when conveyed by language. Using event-related brain potentials (ERPs), we examined the brain response to third-person pronouns (lei “she” and lui “he”) that were implicitly primed by definitional (passeggeraFEM “passenger”, pensionatoMASC “pensioner”), or stereotypical antecedents (insegnante “teacher”, conducente “driver”). An N400-like effect on the pronoun emerged when it was preceded by a definitionally incongruent prime (passeggeraFEM – lui; pensionatoMASC – lei), and a stereotypically incongruent prime for masculine pronouns only (insegnante – lui). In addition, a P300-like effect was found when the pronoun was preceded by definitionally incongruent primes. However, this effect was observed for female, but not male participants. Overall, these results provide further evidence for on-line effects of stereotypical gender in language comprehension. Importantly, our results also suggest a gender stereotype asymmetry in that male and female stereotypes affected the processing of pronouns differently. PMID:23226494

  15. An empirical reevaluation of absolute pitch: behavioral and electrophysiological measurements.

    PubMed

    Elmer, Stefan; Sollberger, Silja; Meyer, Martin; Jäncke, Lutz

    2013-10-01

    Here, we reevaluated the "two-component" model of absolute pitch (AP) by combining behavioral and electrophysiological measurements. This specific model postulates that AP is driven by a perceptual encoding ability (i.e., pitch memory) plus an associative memory component (i.e., pitch labeling). To test these predictions, during EEG measurements AP and non-AP (NAP) musicians were passively exposed to piano tones (first component of the model) and additionally instructed to judge whether combinations of tones and labels were conceptually associated or not (second component of the model). Auditory-evoked N1/P2 potentials did not reveal differences between the two groups, thus indicating that AP is not necessarily driven by a differential pitch encoding ability at the processing level of the auditory cortex. Otherwise, AP musicians performed the conceptual association task with an order of magnitude better accuracy and shorter RTs than NAP musicians did, this result clearly pointing to distinctive conceptual associations in AP possessors. Most notably, this behavioral superiority was reflected by an increased N400 effect and accompanied by a subsequent late positive component, the latter not being distinguishable in NAP musicians. PMID:23647515

  16. Electrophysiological assessment of corticorespiratory pathway function in amyotrophic lateral sclerosis.

    PubMed

    Shimizu, Toshio; Komori, Tetsuo; Kugio, Yumiko; Fujimaki, Yumi; Oyanagi, Kiyomitsu; Hayashi, Hideaki

    2010-01-01

    Respiratory muscle paralysis is inevitable in the clinical course of amyotrophic lateral sclerosis (ALS). Our objective was to electrophysiologically assess the function of the phrenic nerve and diaphragm motor cortex in ALS. Phrenic nerve M waves, diaphragm motor evoked potentials (MEPs) induced by transcranial magnetic stimulation, and their clinical correlations were analyzed in 29 ALS patients. The M wave amplitude was significantly lower in patients than in healthy control subjects (p<0.001). The MEP amplitudes both in the expiratory and inspiratory phases were significantly decreased in patients (p<0.01). In particular, 15 patients showed no MEPs in the expiratory phase, six of whom also showed no MEPs in the inspiratory phase. Five of them had no respiratory complaints. There was a weak, non-significant correlation between the inspiratory MEP amplitude and forced vital capacity (p=0.052). We conclude that the loss of MEP might reflect the subclinical involvement of the voluntary respiratory drive from the diaphragm motor cortex, potentially leading to further respiratory deterioration. PMID:19707909

  17. Canonical Wnt Signaling Regulates Atrioventricular Junction Programming and Electrophysiological Properties

    PubMed Central

    Gillers, Benjamin S; Chiplunkar, Aditi; Aly, Haytham; Valenta, Tomas; Basler, Konrad; Christoffels, Vincent M.; Efimov, Igor R; Boukens, Bastiaan J; Rentschler, Stacey

    2014-01-01

    Rationale Proper patterning of the atrioventricular canal (AVC) is essential for delay of electrical impulses between atria and ventricles, and defects in AVC maturation can result in congenital heart disease. Objective To determine the role of canonical Wnt signaling in the myocardium during AVC development. Methods and Results We utilized a novel allele of β-catenin that preserves β-catenin’s cell adhesive functions but disrupts canonical Wnt signaling, allowing us to probe the effects of Wnt loss of function independently. We show that loss of canonical Wnt signaling in the myocardium results in tricuspid atresia with hypoplastic right ventricle associated with loss of AVC myocardium. In contrast, ectopic activation of Wnt signaling was sufficient to induce formation of ectopic AV junction-like tissue as assessed by morphology, gene expression, and electrophysiologic criteria. Aberrant AVC development can lead to ventricular preexcitation, a characteristic feature of Wolff-Parkinson-White syndrome. We demonstrate that postnatal activation of Notch signaling downregulates canonical Wnt targets within the AV junction. Stabilization of β-catenin protein levels can rescue Notch-mediated ventricular preexcitation and dysregulated ion channel gene expression. Conclusions Our data demonstrate that myocardial canonical Wnt signaling is an important regulator of AVC maturation and electrical programming upstream of Tbx3. Our data further suggests that ventricular preexcitation may require both morphologic patterning defects, as well as myocardial lineage reprogramming, to allow robust conduction across accessory pathway tissue. PMID:25599332

  18. Differential Electrophysiological Responses to Odorant Isotopologues in Drosophilid Antennae123

    PubMed Central

    Drimyli, Efstathia; Gaitanidis, Alexandros; Maniati, Klio; Turin, Luca

    2016-01-01

    Abstract Olfaction presents the ultimate challenge to molecular recognition as thousands of molecules have to be recognized by far fewer olfactory receptors. We have presented evidence that Drosophila readily distinguish odorants based on their molecular vibrations using a battery of behavioral assays suggesting engagement of a molecular vibration-sensing component. Here we interrogate electrophysiologically the antennae of four Drosophilids and demonstrate conserved differential response amplitudes to aldehydes, alcohols, ketones, nitriles, and their deuterated isotopologues. Certain deuterated odorants evoked larger electroantennogram (EAG) amplitudes, while the response to the normal odorant was elevated in others. Significantly, benzonitrile isotopologues were not distinguishable as predicted. This suggests that isotopologue-specific EAG amplitudes result from differential activation of specific olfactory receptors. In support of this, odorants with as few as two deuteria evoke distinct EAG amplitudes from their normal isotopologues, and this is independent of the size of the deuterated molecule. Importantly, we find no evidence that these isotopologue-specific amplitudes depend on perireceptor mechanisms or other pertinent physical property of the deuterated odorants. Rather, our results strongly suggest that Drosophilid olfactory receptors are activated by molecular vibrations differentiating similarly sized and shaped odorants in vivo, yielding sufficient differential information to drive behavioral choices. PMID:27351023

  19. A recording chamber for small volume slice electrophysiology.

    PubMed

    Dondzillo, Anna; Quinn, Kevin D; Cruickshank-Quinn, Charmion I; Reisdorph, Nichole; Lei, Tim C; Klug, Achim

    2015-09-01

    Electrophysiological recordings from brain slices are typically performed in small recording chambers that allow for the superfusion of the tissue with artificial extracellular solution (ECS), while the chamber holding the tissue is mounted in the optical path of a microscope to image neurons in the tissue. ECS itself is inexpensive, and thus superfusion rates and volumes of ECS consumed during an experiment using standard ECS are not critical. However, some experiments require the addition of expensive pharmacological agents or other chemical compounds to the ECS, creating a need to build superfusion systems that operate on small volumes while still delivering appropriate amounts of oxygen and other nutrients to the tissue. We developed a closed circulation tissue chamber for slice recordings that operates with small volumes of bath solution in the range of 1.0 to 2.6 ml and a constant oxygen/carbon dioxide delivery to the solution in the bath. In our chamber, the ECS is oxygenated and recirculated directly in the recording chamber, eliminating the need for tubes and external bottles/containers to recirculate and bubble ECS and greatly reducing the total ECS volume required for superfusion. At the same time, the efficiency of tissue oxygenation and health of the section are comparable to standard superfusion methods. We also determined that the small volume of ECS contains a sufficient amount of nutrients to support the health of a standard brain slice for several hours without concern for either depletion of nutrients or accumulation of waste products. PMID:26203105

  20. Differential Electrophysiological Responses to Odorant Isotopologues in Drosophilid Antennae.

    PubMed

    Drimyli, Efstathia; Gaitanidis, Alexandros; Maniati, Klio; Turin, Luca; Skoulakis, Efthimios M C

    2016-01-01

    Olfaction presents the ultimate challenge to molecular recognition as thousands of molecules have to be recognized by far fewer olfactory receptors. We have presented evidence that Drosophila readily distinguish odorants based on their molecular vibrations using a battery of behavioral assays suggesting engagement of a molecular vibration-sensing component. Here we interrogate electrophysiologically the antennae of four Drosophilids and demonstrate conserved differential response amplitudes to aldehydes, alcohols, ketones, nitriles, and their deuterated isotopologues. Certain deuterated odorants evoked larger electroantennogram (EAG) amplitudes, while the response to the normal odorant was elevated in others. Significantly, benzonitrile isotopologues were not distinguishable as predicted. This suggests that isotopologue-specific EAG amplitudes result from differential activation of specific olfactory receptors. In support of this, odorants with as few as two deuteria evoke distinct EAG amplitudes from their normal isotopologues, and this is independent of the size of the deuterated molecule. Importantly, we find no evidence that these isotopologue-specific amplitudes depend on perireceptor mechanisms or other pertinent physical property of the deuterated odorants. Rather, our results strongly suggest that Drosophilid olfactory receptors are activated by molecular vibrations differentiating similarly sized and shaped odorants in vivo, yielding sufficient differential information to drive behavioral choices. PMID:27351023

  1. Application of Parallel Factor Analysis (PARAFAC) to electrophysiological data

    PubMed Central

    Schmitz, S. Katharina; Hasselbach, Philipp P.; Ebisch, Boris; Klein, Anja; Pipa, Gordon; Galuske, Ralf A. W.

    2015-01-01

    The identification of important features in multi-electrode recordings requires the decomposition of data in order to disclose relevant features and to offer a clear graphical representation. This can be a demanding task. Parallel Factor Analysis (PARAFAC; Hitchcock, 1927; Carrol and Chang, 1970; Harshman, 1970) is a method to decompose multi-dimensional arrays in order to focus on the features of interest, and provides a distinct illustration of the results. We applied PARAFAC to analyse spatio-temporal patterns in the functional connectivity between neurons, as revealed in their spike trains recorded in cat primary visual cortex (area 18). During these recordings we reversibly deactivated feedback connections from higher visual areas in the pMS (posterior middle suprasylvian) cortex in order to study the impact of these top-down signals. Cross correlation was computed for every possible pair of the 16 electrodes in the electrode array. PARAFAC was then used to reveal the effects of time, stimulus, and deactivation condition on the correlation patterns. Our results show that PARAFAC is able to reliably extract changes in correlation strength for different experimental conditions and display the relevant features. Thus, PARAFAC proves to be well-suited for the use in the context of electrophysiological (action potential) recordings. PMID:25688205

  2. Electrophysiological CNS-processes related to associative learning in humans.

    PubMed

    Christoffersen, Gert R J; Schachtman, Todd R

    2016-01-01

    The neurophysiology of human associative memory has been studied with electroencephalographic techniques since the 1930s. This research has revealed that different types of electrophysiological processes in the human brain can be modified by conditioning: sensory evoked potentials, sensory induced gamma-band activity, periods of frequency-specific waves (alpha and beta waves, the sensorimotor rhythm and the mu-rhythm) and slow cortical potentials. Conditioning of these processes has been studied in experiments that either use operant conditioning or repeated contingent pairings of conditioned and unconditioned stimuli (classical conditioning). In operant conditioning, the appearance of a specific brain process is paired with an external stimulus (neurofeedback) and the feedback enables subjects to obtain varying degrees of control of the CNS-process. Such acquired self-regulation of brain activity has found practical uses for instance in the amelioration of epileptic seizures, Autism Spectrum Disorders (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). It has also provided communicative means of assistance for tetraplegic patients through the use of brain computer interfaces. Both extra and intracortically recorded signals have been coupled with contingent external feedback. It is the aim for this review to summarize essential results on all types of electromagnetic brain processes that have been modified by classical or operant conditioning. The results are organized according to type of conditioned EEG-process, type of conditioning, and sensory modalities of the conditioning stimuli. PMID:26367470

  3. Simulating Cardiac Electrophysiology Using Unstructured All-Hexahedra Spectral Elements

    PubMed Central

    Cuccuru, Gianmauro; Fotia, Giorgio; Maggio, Fabio; Southern, James

    2015-01-01

    We discuss the application of the spectral element method to the monodomain and bidomain equations describing propagation of cardiac action potential. Models of cardiac electrophysiology consist of a system of partial differential equations coupled with a system of ordinary differential equations representing cell membrane dynamics. The solution of these equations requires solving multiple length scales due to the ratio of advection to diffusion that varies among the different equations. High order approximation of spectral elements provides greater flexibility in resolving multiple length scales. Furthermore, spectral elements are extremely efficient to model propagation phenomena on complex shapes using fewer degrees of freedom than its finite element equivalent (for the same level of accuracy). We illustrate a fully unstructured all-hexahedra approach implementation of the method and we apply it to the solution of full 3D monodomain and bidomain test cases. We discuss some key elements of the proposed approach on some selected benchmarks and on an anatomically based whole heart human computational model. PMID:26583112

  4. Spectrally resolved fast transient brain states in electrophysiological data.

    PubMed

    Vidaurre, Diego; Quinn, Andrew J; Baker, Adam P; Dupret, David; Tejero-Cantero, Alvaro; Woolrich, Mark W

    2016-02-01

    The brain is capable of producing coordinated fast changing neural dynamics across multiple brain regions in order to adapt to rapidly changing environments. However, it is non-trivial to identify multiregion dynamics at fast sub-second time-scales in electrophysiological data. We propose a method that, with no knowledge of any task timings, can simultaneously identify and describe fast transient multiregion dynamics in terms of their temporal, spectral and spatial properties. The approach models brain activity using a discrete set of sequential states, with each state distinguished by its own multiregion spectral properties. This can identify potentially very short-lived visits to a brain state, at the same time as inferring the state's properties, by pooling over many repeated visits to that state. We show how this can be used to compute state-specific measures such as power spectra and coherence. We demonstrate that this can be used to identify short-lived transient brain states with distinct power and functional connectivity (e.g., coherence) properties in an MEG data set collected during a volitional motor task. PMID:26631815

  5. A low-cost, open-source, wireless electrophysiology system.

    PubMed

    Ghomashchi, A; Zheng, Z; Majaj, N; Trumpis, M; Kiorpes, L; Viventi, J

    2014-01-01

    Many experiments in neuroscience require or would benefit tremendously from a wireless neural recording system. However, commercially available wireless systems are expensive, have moderate to high noise and are often not customizable. Academic wireless systems present impressive capabilities, but are not available for other labs to use. To overcome these limitations, we have developed an ultra-low noise 8 channel wireless electrophysiological data acquisition system using standard, commercially available components. The system is capable of recording many types of neurological signals, including EEG, ECoG, LFP and unit activity. With a diameter of just 25 mm and height of 9 mm, including a CR2032 Lithium coin cell battery, it is designed to fit into a small recording chamber while minimizing the overall implant height (Fig. 1 and 3). Using widely available parts we were able to keep the material cost of our system under $100 dollars. The complete design, including schematic, PCB layout, bill of materials and source code, will be released through an open source license, allowing other labs to modify the design to fit their needs. We have also developed a driver to acquire data using the BCI2000 software system. Feedback from the community will allow us to improve the design and create a more useful neuroscience research tool. PMID:25570656

  6. Electrophysiological Correlates of Long-Term Soto Zen Meditation

    PubMed Central

    Pasquini, Henrique Adam; Tanaka, Guaraci Ken; Basile, Luis Fernando Hindi; Velasques, Bruna; Lozano, Mirna Delposo

    2015-01-01

    This study aimed to verify the electrophysiological correlates of the changes in long-term regular meditators. We use modern techniques of high-resolution electroencephalography applied to slow potentials, power spectra, and potencies related to the events. To obtain encephalographic records, we use an assembly of 128 channels in 31 subjects (17 Soto Zen Buddhist meditators). The motivation of this study was to determine whether the induced beta power would present an increase in meditators as well as a decrease in induced theta/beta ratio in absolute and relative values. However, opposite to what we expected, no significant change was found in the beta frequency. In contrast, the main findings of the study were correlations between the frequency of weekly meditation practice and the increased theta induced relative power, increase of induced power ratio (ratio theta/beta), and increase of the ratio of induced relative powers (theta/beta ratio) during our task that featured an “adapted meditation,” suggesting that the meditative state of “mindfulness” is much more related to the permittivity of “distractions” by the meditators, with a deliberate reduction of attention. PMID:25632397

  7. Electrophysiology of human cardiac atrial and ventricular telocytes.

    PubMed

    Sheng, Jingwei; Shim, Winston; Lu, Jun; Lim, Sze Yun; Ong, Boon Hean; Lim, Tien Siang; Liew, Reginald; Chua, Yeow Leng; Wong, Philip

    2014-02-01

    Telocytes (TCs) with exceptionally long cellular processes of telopodes have been described in human epicardium to act as structural supporting cells in the heart. We examined myocardial chamber-specific TCs identified in atrial and ventricular fibroblast culture using immunocytochemistry and studied their electrophysiological property by whole-cell patch clamp. Atrial and ventricular TCs with extended telopodes and alternating podoms and podomers that expressed CD34, c-Kit and PDGFR-β were identified. These cells expressed large conductance Ca²⁺-activated K⁺ current (BK(Ca)) and inwardly rectifying K⁺ current (IK(ir)), but not transient outward K⁺ current (I(to)) and ATP-sensitive potassium current (K(ATP)). The active channels were functionally competent with demonstrated modulatory response to H2 S and transforming growth factor (TGF)-β1 whereby H₂S significantly inhibited the stimulatory effect of TGF-β1 on current density of both BKCa and IK(ir). Furthermore, H₂S attenuated TGF-β1-stimulated KCa1.1/Kv1.1 (encode BK(Ca)) and Kir2.1 (encode IK(ir)) expression in TCs. Our results show that functionally competent K⁺ channels are present in human atrial and ventricular TCs and their modulation may have significant implications in myocardial physiopathology. PMID:24467431

  8. Myokit: A simple interface to cardiac cellular electrophysiology.

    PubMed

    Clerx, Michael; Collins, Pieter; de Lange, Enno; Volders, Paul G A

    2016-01-01

    Myokit is a new powerful and versatile software tool for modeling and simulation of cardiac cellular electrophysiology. Myokit consists of an easy-to-read modeling language, a graphical user interface, single and multi-cell simulation engines and a library of advanced analysis tools accessible through a Python interface. Models can be loaded from Myokit's native file format or imported from CellML. Model export is provided to C, MATLAB, CellML, CUDA and OpenCL. Patch-clamp data can be imported and used to estimate model parameters. In this paper, we review existing tools to simulate the cardiac cellular action potential to find that current tools do not cater specifically to model development and that there is a gap between easy-to-use but limited software and powerful tools that require strong programming skills from their users. We then describe Myokit's capabilities, focusing on its model description language, simulation engines and import/export facilities in detail. Using three examples, we show how Myokit can be used for clinically relevant investigations, multi-model testing and parameter estimation in Markov models, all with minimal programming effort from the user. This way, Myokit bridges a gap between performance, versatility and user-friendliness. PMID:26721671

  9. Structural Defects Lead to Dynamic Entrapment in Cardiac Electrophysiology

    PubMed Central

    Bates, Oliver R. J.; Suki, Bela; Spector, Peter S.; Bates, Jason H. T.

    2015-01-01

    Biological networks are typically comprised of many parts whose interactions are governed by nonlinear dynamics. This potentially imbues them with the ability to support multiple attractors, and therefore to exhibit correspondingly distinct patterns of behavior. In particular, multiple attractors have been demonstrated for the electrical activity of the diseased heart in situations where cardioversion is able to convert a reentrant arrhythmia to a stable normal rhythm. Healthy hearts, however, are typically resilient to abnormal rhythms. This raises the question as to how a healthy cardiac cell network must be altered so that it can support multiple distinct behaviors. Here we demonstrate how anatomic defects can give rise to multi-stability in the heart as a function of the electrophysiological properties of the cardiac tissue and the timing of activation of ectopic foci. This leads to a form of hysteretic behavior, which we call dynamic entrapment, whereby the heart can become trapped in aberrant attractor as a result of a transient change in tissue properties. We show that this can lead to a highly inconsistent relationship between clinical symptoms and underlying pathophysiology, which raises the possibility that dynamic entrapment may underlie other forms of chronic idiopathic illness. PMID:25756656

  10. Electrophysiological Signature of Homomeric and Heteromeric Glycine Receptor Channels.

    PubMed

    Raltschev, Constanze; Hetsch, Florian; Winkelmann, Aline; Meier, Jochen C; Semtner, Marcus

    2016-08-19

    Glycine receptors are chloride-permeable, ligand-gated ion channels and contribute to the inhibition of neuronal firing in the central nervous system or to facilitation of neurotransmitter release if expressed at presynaptic sites. Recent structure-function studies have provided detailed insights into the mechanisms of channel gating, desensitization, and ion permeation. However, most of the work has focused only on comparing a few isoforms, and among studies, different cellular expression systems were used. Here, we performed a series of experiments using recombinantly expressed homomeric and heteromeric glycine receptor channels, including their splice variants, in the same cellular expression system to investigate and compare their electrophysiological properties. Our data show that the current-voltage relationships of homomeric channels formed by the α2 or α3 subunits change upon receptor desensitization from a linear to an inwardly rectifying shape, in contrast to their heteromeric counterparts. The results demonstrate that inward rectification depends on a single amino acid (Ala(254)) at the inner pore mouth of the channels and is closely linked to chloride permeation. We also show that the current-voltage relationships of glycine-evoked currents in primary hippocampal neurons are inwardly rectifying upon desensitization. Thus, the alanine residue Ala(254) determines voltage-dependent rectification upon receptor desensitization and reveals a physio-molecular signature of homomeric glycine receptor channels, which provides unprecedented opportunities for the identification of these channels at the single cell level. PMID:27382060

  11. Electrophysiological correlates of morphological processing in Chinese compound word recognition

    PubMed Central

    Du, Yingchun; Hu, Weiping; Fang, Zhuo; Zhang, John X.

    2013-01-01

    The present study investigated the electrophysiological correlates of morphological processing in Chinese compound word reading using a delayed repetition priming paradigm. Participants were asked to passively view lists of two-character compound words containing prime-target pairs separated by a few items. In a Whole Word repetition condition, the prime and target were the same real words (e.g., , manager-manager). In a Constituent repetition condition, the prime and target were swapped in terms of their constituent position (e.g., , the former is a pseudo-word and the later means nurse). Two ERP components including N200 and N400 showed repetition effects. The N200 showed a negative shift upon repetition in the Whole Word condition but this effect was delayed for the Constituent condition. The N400 showed comparable amplitude reduction across the two priming conditions. The results reveal different aspects of morphological processing with an early stage associated with N200 and a late stage with N400. There was also a possibility that the N200 effect reflect general cognitive processing, i.e., the detection of low-probability stimuli. PMID:24068994

  12. First steps towards initial registration for electrophysiology procedures

    NASA Astrophysics Data System (ADS)

    Brost, Alexander; Bourier, Felix; Yatziv, Liron; Koch, Martin; Hornegger, Joachim; Strobel, Norbert; Kurzidim, Klaus

    2011-03-01

    Atrial fibrillation is the most common heart arrhythmia and a leading cause of stroke. The treatment option of choice is radio-frequency catheter ablation, which is performed in electrophysiology labs using C-Arm X-ray systems for navigation and guidance. The goal is to electrically isolate the pulmonary vein-left atrial junction thereby rendering myocardial fibers responsible for induction and maintenance of AF inactive. The use of overlay images for fluoroscopic guidance may improve the quality of the ablation procedure, and can reduce procedure time. Overlay images, acquired using CT, MRI, or C-arm CT, can add soft-tissue information, otherwise not visible under X-ray. MRI can be used to image a wide variety of anatomical details without ionizing radiation. In this paper, we present a method to register a 3-D MRI volume to 2-D biplane X-ray images using the coronary sinus. Current approaches require registration of the overlay images to the fluoroscopic images to be performed after the trans-septal puncture, when contast agent can be administered. We present a new approach for registration to align overlay images before the trans-septal puncture. To this end, we manually extract the coronary sinus from pre-operative MRI and register it to a multi-electorde catheter placed in the coronary sinus.

  13. Intending to forget is not easy: Behavioral and electrophysiological evidence.

    PubMed

    Gao, Heming; Cao, Bihua; Zhang, Qi; Qi, Mingming; Li, Fuhong; Li, Hong

    2016-06-01

    Previous researches have shown that recognition accuracy is lower for items cued to-be-forgotten (TBF) than to-be-remembered (TBR). Does directed forgetting help people forget more items than non-directed forgetting? Here, we modified the directed forgetting paradigm by adding a non-cue condition (NC). Consequently, non-directed forgetting would occur in NC. Behavioral results showed higher recognition accuracy for TBF than NC items, indicating that directed forgetting is less effective than non-directed forgetting. Electrophysiological results indicated that: (1) Remembered TBF items evoke an increased late positive component (LPC) than remembered NC items; (2) compared with remembered NC items, remembered TBF items showed a pronounced left-lateralized old/new effect and a reduced right-lateralized reversed old/new effect; (3) a right-lateralized reversed old/new effect was observed for forgotten TBF, but it was absent for forgotten NC items. These results demonstrate that the TBF items have a greater memory trace than the NC items. Forgetting cue has little effect of forgetting item from memory, and it might prompt subject to process or at least focus attention on the TBF items. PMID:27021846

  14. Spectrally resolved fast transient brain states in electrophysiological data

    PubMed Central

    Vidaurre, Diego; Quinn, Andrew J.; Baker, Adam P.; Dupret, David; Tejero-Cantero, Alvaro; Woolrich, Mark W.

    2016-01-01

    The brain is capable of producing coordinated fast changing neural dynamics across multiple brain regions in order to adapt to rapidly changing environments. However, it is non-trivial to identify multiregion dynamics at fast sub-second time-scales in electrophysiological data. We propose a method that, with no knowledge of any task timings, can simultaneously identify and describe fast transient multiregion dynamics in terms of their temporal, spectral and spatial properties. The approach models brain activity using a discrete set of sequential states, with each state distinguished by its own multiregion spectral properties. This can identify potentially very short-lived visits to a brain state, at the same time as inferring the state's properties, by pooling over many repeated visits to that state. We show how this can be used to compute state-specific measures such as power spectra and coherence. We demonstrate that this can be used to identify short-lived transient brain states with distinct power and functional connectivity (e.g., coherence) properties in an MEG data set collected during a volitional motor task. PMID:26631815

  15. Effects of context on electrophysiological response to musical accents.

    PubMed

    Palmer, Caroline; Jewett, Lisa R; Steinhauer, Karsten

    2009-07-01

    Listeners' aesthetic and emotional responses to music typically occur in the context of long musical passages that contain structures defined in terms of the events that precede them. We describe an electrophysiological study of listeners' brain responses to musical accents that coincided in longer musical sequences. Musically trained listeners performed a timbre-change detection task in which a single-tone timbre change was positioned within 4-bar melodies composed of 350-ms tones to coincide or not with melodic contour accents and temporal accents (induced with temporal gaps). Event-related potential responses to (task-relevant) attended timbre changes elicited an early negativity (MMN/N2b) around 200 ms and a late positive component around 350 ms (P300), reflecting updating of the timbre change in working memory. The amplitudes of both components changed systematically across the sequence, consistent with expectancy-based context effects. Furthermore, melodic contour changes modulated the MMN/N2b response (but not the P300) to timbre changes in later sequence positions. In contrast, task-irrelevant temporal gaps elicited an MMN that was not modulated by position within the context; absence of a P300 indicated that temporal-gap accents were not updated in working memory. Listeners' neural responses to musical structure changed systematically as sequential predictability and listeners' expectations changed across the melodic context. PMID:19673825

  16. Automatically Generated, Anatomically Accurate Meshes for Cardiac Electrophysiology Problems

    PubMed Central

    Prassl, Anton J.; Kickinger, Ferdinand; Ahammer, Helmut; Grau, Vicente; Schneider, Jürgen E.; Hofer, Ernst; Vigmond, Edward J.; Trayanova, Natalia A.

    2010-01-01

    Significant advancements in imaging technology and the dramatic increase in computer power over the last few years broke the ground for the construction of anatomically realistic models of the heart at an unprecedented level of detail. To effectively make use of high-resolution imaging datasets for modeling purposes, the imaged objects have to be discretized. This procedure is trivial for structured grids. However, to develop generally applicable heart models, unstructured grids are much preferable. In this study, a novel image-based unstructured mesh generation technique is proposed. It uses the dual mesh of an octree applied directly to segmented 3-D image stacks. The method produces conformal, boundary-fitted, and hexahedra-dominant meshes. The algorithm operates fully automatically with no requirements for interactivity and generates accurate volume-preserving representations of arbitrarily complex geometries with smooth surfaces. The method is very well suited for cardiac electrophysiological simulations. In the myocardium, the algorithm minimizes variations in element size, whereas in the surrounding medium, the element size is grown larger with the distance to the myocardial surfaces to reduce the computational burden. The numerical feasibility of the approach is demonstrated by discretizing and solving the monodomain and bidomain equations on the generated grids for two preparations of high experimental relevance, a left ventricular wedge preparation, and a papillary muscle. PMID:19203877

  17. Electrophysiological measurement of interest during walking in a simulated environment.

    PubMed

    Takeda, Yuji; Okuma, Takashi; Kimura, Motohiro; Kurata, Takeshi; Takenaka, Takeshi; Iwaki, Sunao

    2014-09-01

    A reliable neuroscientific technique for objectively estimating the degree of interest in a real environment is currently required in the research fields of neuroergonomics and neuroeconomics. Toward the development of such a technique, the present study explored electrophysiological measures that reflect an observer's interest in a nearly-real visual environment. Participants were asked to walk through a simulated shopping mall and the attractiveness of the shopping mall was manipulated by opening and closing the shutters of stores. During the walking task, participants were exposed to task-irrelevant auditory probes (two-stimulus oddball sequence). The results showed a smaller P2/early P3a component of task-irrelevant auditory event-related potentials and a larger lambda response of eye-fixation-related potentials in an interesting environment (i.e., open-shutter condition) than in a boring environment (i.e., closed-shutter condition); these findings can be reasonably explained by supposing that participants allocated more attentional resources to visual information in an interesting environment than in a boring environment, and thus residual attentional resources that could be allocated to task-irrelevant auditory probes were reduced. The P2/early P3a component and the lambda response may be useful measures of interest in a real visual environment. PMID:24892726

  18. Ion Channel ElectroPhysiology Ontology (ICEPO) – a case study of text mining assisted ontology development

    PubMed Central

    Elayavilli, Ravikumar Komandur; Liu, Hongfang

    2016-01-01

    Background Computational modeling of biological cascades is of great interest to quantitative biologists. Biomedical text has been a rich source for quantitative information. Gathering quantitative parameters and values from biomedical text is one significant challenge in the early steps of computational modeling as it involves huge manual effort. While automatically extracting such quantitative information from bio-medical text may offer some relief, lack of ontological representation for a subdomain serves as impedance in normalizing textual extractions to a standard representation. This may render textual extractions less meaningful to the domain experts. Methods In this work, we propose a rule-based approach to automatically extract relations involving quantitative data from biomedical text describing ion channel electrophysiology. We further translated the quantitative assertions extracted through text mining to a formal representation that may help in constructing ontology for ion channel events using a rule based approach. We have developed Ion Channel ElectroPhysiology Ontology (ICEPO) by integrating the information represented in closely related ontologies such as, Cell Physiology Ontology (CPO), and Cardiac Electro Physiology Ontology (CPEO) and the knowledge provided by domain experts. Results The rule-based system achieved an overall F-measure of 68.93% in extracting the quantitative data assertions system on an independently annotated blind data set. We further made an initial attempt in formalizing the quantitative data assertions extracted from the biomedical text into a formal representation that offers potential to facilitate the integration of text mining into ontological workflow, a novel aspect of this study. Conclusions This work is a case study where we created a platform that provides formal interaction between ontology development and text mining. We have achieved partial success in extracting quantitative assertions from the biomedical text

  19. Active Contraction of Microtubule Networks

    NASA Astrophysics Data System (ADS)

    Foster, Peter; Fürthauer, Sebastian; Shelley, Michael; Needleman, Daniel

    Many cellular processes are driven by cytoskeletal assemblies. It remains unclear how cytoskeletal filaments and motor proteins organize into cellular scale structures and how molecular properties of cytoskeletal components affect the large scale behaviors of these systems. Here we investigate the self-organization of stabilized microtubules in Xenopus oocyte extracts and find that they can form macroscopic networks that spontaneously contract. We propose that these contractions are driven by the clustering of microtubule minus ends by dynein. Based on this idea, we construct an active fluid theory of network contractions which predicts a dependence of the timescale of contraction on initial network geometry, a development of density inhomogeneities during contraction, a constant final network density, and a strong influence of dynein inhibition on the rate of contraction, all in quantitative agreement with experiments. These results demonstrate that the motor-driven clustering of filament ends is a generic mechanism leading to contraction.

  20. Active contraction of microtubule networks.

    PubMed

    Foster, Peter J; Fürthauer, Sebastian; Shelley, Michael J; Needleman, Daniel J

    2015-01-01

    Many cellular processes are driven by cytoskeletal assemblies. It remains unclear how cytoskeletal filaments and motor proteins organize into cellular scale structures and how molecular properties of cytoskeletal components affect the large-scale behaviors of these systems. Here, we investigate the self-organization of stabilized microtubules in Xenopus oocyte extracts and find that they can form macroscopic networks that spontaneously contract. We propose that these contractions are driven by the clustering of microtubule minus ends by dynein. Based on this idea, we construct an active fluid theory of network contractions, which predicts a dependence of the timescale of contraction on initial network geometry, a development of density inhomogeneities during contraction, a constant final network density, and a strong influence of dynein inhibition on the rate of contraction, all in quantitative agreement with experiments. These results demonstrate that the motor-driven clustering of filament ends is a generic mechanism leading to contraction. PMID:26701905

  1. Interpretation of 2-probe turbulence measurements in an axisymmetric contraction

    NASA Technical Reports Server (NTRS)

    Marion-Moulin, C.; Tan-Atichat, J.; Nagib, H. M.

    1983-01-01

    Simultaneous measurements of the streamwise and radial velocity components at two points, one on and one off the centerline with variable radial separation, were digitally recorded and processed at several stations along a four to one contraction with controlled upstream turbulence conditions. Various statistical quantities are presented including spectra and coherence functions. The integral L sub ux, L sub um, L sub vx, L sub vm were also estimated and their variation along the contraction is examined.

  2. Swelling and Contraction of Phaseolus Hypocotyl Mitochondria 1

    PubMed Central

    Earnshaw, M. J.; Truelove, B.

    1968-01-01

    Isolated Phaseolus mitochondria will swell spontaneously in buffered KCl and contract with an oxidizable substrate or ATP + Mg2+. The conditions under which the mitochondria are swollen affect subsequent contraction, substrate oxidation and ion accumulation, but not their oxidative phosphorylation ability. Bovine serum albumin reduces the rate of swelling and promotes substrate oxidation, contraction and ion accumulation. Swelling of these mitochondria is associated with the release of malic dehydrogenase and a loss of membrane integrity. The beneficial effects of bovine serum albumin in preserving the energy linked functions of Phaseolus mitochondria is discussed. PMID:16656729

  3. The Lanthanide Contraction Revisited

    SciTech Connect

    Seitz, Michael; Oliver, Allen G.; Raymond, Kenneth N.

    2007-04-19

    A complete, isostructural series of lanthanide complexes (except Pm) with the ligand TREN-1,2-HOIQO has been synthesized and structurally characterized by means of single-crystal X-ray analysis. All complexes are 1D-polymeric species in the solid state, with the lanthanide being in an eight-coordinate, distorted trigonal-dodecahedral environment with a donor set of eight unique oxygen atoms. This series constitutes the first complete set of isostructural lanthanide complexes with a ligand of denticity greater than two. The geometric arrangement of the chelating moieties slightly deviates across the lanthanide series, as analyzed by a shape parameter metric based on the comparison of the dihedral angles along all edges of the coordination polyhedron. The apparent lanthanide contraction in the individual Ln-O bond lengths deviates considerably from the expected quadratic decrease that was found previously in a number of complexes with ligands of low denticity. The sum of all bond lengths around the trivalent metal cation, however, is more regular, showing an almost ideal quadratic behavior across the entire series. The quadratic nature of the lanthanide contraction is derived theoretically from Slater's model for the calculation of ionic radii. In addition, the sum of all distances along the edges of the coordination polyhedron show exactly the same quadratic dependency as the Ln-X bond lengths. The universal validity of this coordination sphere contraction, concomitant with the quadratic decrease in Ln-X bond lengths, was confirmed by reexamination of four other, previously published, almost complete series of lanthanide complexes. Due to the importance of multidentate ligands for the chelation of rare-earth metals, this result provides a significant advance for the prediction and rationalization of the geometric features of the corresponding lanthanide complexes, with great potential impact for all aspects of lanthanide coordination.

  4. 42 CFR 434.6 - General requirements for all contracts and subcontracts. P>(a) Contracts. All contracts under...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... contracts and subcontracts.P>(a) Contracts. All contracts under this part must include all of the following: (1) Include provisions that define a sound and complete procurement contract, as required by 45 CFR... subcontracts. P>(a) Contracts. All contracts under this part must include all of the following: 434.6...

  5. 48 CFR 3035.7000 - Contract clause.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SECURITY ACQUISITION REGULATION (HSAR) SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING Information Dissemination by Educational Institutions 3035.7000 Contract clause. The contracting officer may use the clause at (HSAR) 48 CFR 3052.235-70, Dissemination of...

  6. 48 CFR 3035.7000 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SECURITY ACQUISITION REGULATION (HSAR) SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING Information Dissemination by Educational Institutions 3035.7000 Contract clause. The contracting officer may use the clause at (HSAR) 48 CFR 3052.235-70, Dissemination of...

  7. 48 CFR 39.107 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACTING ACQUISITION OF INFORMATION TECHNOLOGY General 39.107 Contract clause. The contracting officer..., in solicitations and contracts for information technology which require security of information... information technology services or support services....

  8. 48 CFR 1235.7000 - Contract clause.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING Research Misconduct 1235.7000 Contract clause. The contracting officer shall insert the clause at (TAR) 48 CFR 1252.235-70, Research Misconduct, in... Policy on Research Misconduct,” dated February 2002....

  9. 48 CFR 1235.7000 - Contract clause.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING Research Misconduct 1235.7000 Contract clause. The contracting officer shall insert the clause at (TAR) 48 CFR 1252.235-70, Research Misconduct, in... Policy on Research Misconduct,” dated February 2002....

  10. 48 CFR 1235.7000 - Contract clause.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING Research Misconduct 1235.7000 Contract clause. The contracting officer shall insert the clause at (TAR) 48 CFR 1252.235-70, Research Misconduct, in... Policy on Research Misconduct,” dated February 2002....

  11. 48 CFR 1632.617 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... HEALTH BENEFITS ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Debts 1632.617 Contract clause. The clause at (FAR) 48 CFR 52.232-17 will be modified in all FEHBP...

  12. Electrophysiology in the eukaryotic model cell Saccharomyces cerevisiae.

    PubMed

    Bertl, A; Bihler, H; Kettner, C; Slayman, C L

    1998-11-01

    Since the mid-1980s, use of the budding yeast, Saccharomyces cerevisiae, for expression of heterologous (foreign) genes and proteins has burgeoned for several major purposes, including facile genetic manipulation, large-scale production of specific proteins, and preliminary functional analysis. Expression of heterologous membrane proteins in yeast has not kept pace with expression of cytoplasmic proteins for two principal reasons: (1) although plant and fungal proteins express and function easily in yeast membranes, animal proteins do not, at least yet; and (2) the yeast plasma membrane is generally regarded as a difficult system to which to apply the standard electrophysiological techniques for detailed functional analysis of membrane proteins. Especially now, since completion of the genome-sequencing project for Saccharomyces, yeast membranes themselves can be seen as an ample source of diverse membrane proteins - including ion channels, pumps, and cotransporters - which lend themselves to electrophysiological analysis, and specifically to patch-clamping. Using some of these native proteins for assay, we report systematic methods to prepare both the yeast plasma membrane and the yeast vacuolar membrane (tonoplast) for patch-clamp experiments. We also describe optimized ambient conditions - such as electrode preparation, buffer solutions, and time regimens - which facilitate efficient patch recording from Saccharomyces membranes. There are two main keys to successful patch-clamping with Saccharomyces. The first is patience; the second is scrupulous cleanliness. Large cells, such as provided by polyploid strains, are also useful in yeast patch recording, especially while the skill required for gigaseal formation is being learned. Cleanliness is aided by (1) osmotic extrusion of protoplasts, after minimal digestion of yeast walls; (2) use of a rather spare suspension of protoplasts in the recording chamber; (3) maintenance of continuous chamber perfusion prior to

  13. A microfluidic device for whole-animal drug screening using electrophysiological measures in the nematode C. elegans

    PubMed Central

    Hulme, S. Elizabeth; Roberts, William M.; Robinson, Kristin J.; Laromaine, Anna; Lindsay, Theodore H.; Whitesides, George M.; Weeks, Janis C.

    2012-01-01

    This paper describes the fabrication and use of a microfluidic device for performing whole-animal chemical screens using non-invasive electrophysiological readouts of neuromuscular function in the nematode worm, C. elegans. The device consists of an array of microchannels to which electrodes are attached to form recording modules capable of detecting the electrical activity of the pharynx, a heart-like neuromuscular organ involved in feeding. The array is coupled to a tree-like arrangement of distribution channels that automatically delivers one nematode to each recording module. The same channels are then used to perfuse the recording modules with test solutions while recording the electropharyngeogram (EPG) from each worm with sufficient sensitivity to detect each pharyngeal contraction. The device accurately reported the acute effects of known anthelmintics (anti-nematode drugs) and also correctly distinguished a specific drug-resistant mutant strain of C. elegans from wild type. The approach described here is readily adaptable to parasitic species for the identification of novel anthelmintics. It is also applicable in toxicology and drug discovery programs for human metabolic and degenerative diseases for which C. elegans is used as a model. PMID:22588281

  14. The Automation of Electrophysiological Experiments and Data Analysis

    NASA Astrophysics Data System (ADS)

    Morton, David L.

    The role of computation in science is continually growing and neuroscience is no exception. Despite this, a severe lack of scientific software infrastructure persists, slowing progress in many domains. In this thesis, we will see how the combination of neuroscience and software engineering can build infrastructure that enables discovery. The first chapter discusses the Turtle Electrophysiology Project, or TEP, an experiment-automation and data-management system. This system has allowed us to automate away some of the most tedious tasks involved in conducting experiments. As a result, we can collect more data in less time, and with fewer errors related to the loss of metadata (information about how the data were collected). Also, since all of the metadata is automatically digitized during the experiment we can now completely automate our analyses. Chapters two and three are examples of research conducted using the ever-evolving TEP system. In the first instance, we used TEP to deliver visual stimuli and handle data-management. In chapter three, the experiments involved delivering electrical stimuli instead of visual stimuli, and much more rigorous analysis. And even though TEP was not specifically designed to handle collecting data this way, the flexible tags system enabled us to do so. Finally, chapter four details the construction of a robust analysis tool called Spikepy. Whereas TEP is specially designed for the turtle preparation we have, Spikepy is a general-purpose spike-sorting application and framework. Spikepy takes flexibility to the extreme by being a plugin-based framework, yet maintaining a very easy to use interface.

  15. Electrophysiological and Anatomical Correlates of Spinal Cord Optical Coherence Tomography

    PubMed Central

    Valente, Maurizio; Krstajic, Nikola; Biella, Gabriele E. M.

    2016-01-01

    Despite the continuous improvement in medical imaging technology, visualizing the spinal cord poses severe problems due to structural or incidental causes, such as small access space and motion artifacts. In addition, positional guidance on the spinal cord is not commonly available during surgery, with the exception of neuronavigation techniques based on static pre-surgical data and of radiation-based methods, such as fluoroscopy. A fast, bedside, intraoperative real-time imaging, particularly necessary during the positioning of endoscopic probes or tools, is an unsolved issue. The objective of our work, performed on experimental rats, is to demonstrate potential intraoperative spinal cord imaging and probe guidance by optical coherence tomography (OCT). Concurrently, we aimed to demonstrate that the electromagnetic OCT irradiation exerted no particular effect at the neuronal and synaptic levels. OCT is a user-friendly, low-cost and endoscopy-compatible photonics-based imaging technique. In particular, by using a Fourier-domain OCT imager, operating at 850 nm wavelength and scanning transversally with respect to the spinal cord, we have been able to: 1) accurately image tissue structures in an animal model (muscle, spine bone, cerebro-spinal fluid, dura mater and spinal cord), and 2) identify the position of a recording microelectrode approaching and inserting into the cord tissue 3) check that the infrared radiation has no actual effect on the electrophysiological activity of spinal neurons. The technique, potentially extendable to full three-dimensional image reconstruction, shows prospective further application not only in endoscopic intraoperative analyses and for probe insertion guidance, but also in emergency and adverse situations (e.g. after trauma) for damage recognition, diagnosis and fast image-guided intervention. PMID:27050096

  16. Electrophysiological effect of rotigaptide in rabbits with heart failure

    PubMed Central

    Liu, Yu; Li, Haitao; Xia, Wenfang; Yu, Shengbo; Huang, Congxin

    2012-01-01

    Introduction Rotigaptide is a new anti-arrhythmic peptide, which has recently been found to increase junctional conductance and prevent ischemia-induced ventricular tachycardia. In this study, we attempted to investigate the effects and mechanisms of rotigaptide on the vulnerability to ventricular arrhythmias in rabbits with heart failure (HF). Material and methods Chronic volume-pressure overload was used to induce HF. After rotigaptide infusion, an electrophysiological study was performed to record monophasic action potential (MAP), determine the effective refractory period (ERP) and ventricular fibrillation threshold (VFT), and assess the susceptibility to ventricular arrhythmia. Finally, real-time PCR was used to detect the changes of connexin 43 (Cx43) mRNA expression. Results HF rabbits exhibited significant down-regulation of Cx43 mRNA, increase of effective refractory period (ERP) and decrease of VFT (p < 0.05, respectively). These changes resulted in an increase of vulnerability to ventricular tachyarrhythmias (VT/VF). Rotigaptide administration shortened ERP (113.3 ±8.6 ms vs. 131.7 ±12.5 ms, p < 0.05), restored VFT (15.0 ±2.0 V vs. 6.3 ±1.4 V, p < 0.05), and decreased the vulnerability to VT/VF. However, short-term rotigaptide treatment had no significant effect on MAP duration (MAP duration at 90% repolarization: 169.3 ±6.0 ms vs. 172.7 ±6.2 ms, p > 0.05) or connexin 43 mRNA expression (p > 0.05). Conclusions Rotigaptide decreases the ERP, elevates VFT, and reduces the vulnerability to ventricular arrhythmias without changing Cx43 expression in rabbits with HF. It may be a promising antiarrhythmic drug for preventing ventricular arrhythmia in HF. PMID:24904675

  17. Visual adaptation provides objective electrophysiological evidence of facial identity discrimination.

    PubMed

    Retter, Talia L; Rossion, Bruno

    2016-07-01

    Discrimination of facial identities is a fundamental function of the human brain that is challenging to examine with macroscopic measurements of neural activity, such as those obtained with functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). Although visual adaptation or repetition suppression (RS) stimulation paradigms have been successfully implemented to this end with such recording techniques, objective evidence of an identity-specific discrimination response due to adaptation at the level of the visual representation is lacking. Here, we addressed this issue with fast periodic visual stimulation (FPVS) and EEG recording combined with a symmetry/asymmetry adaptation paradigm. Adaptation to one facial identity is induced through repeated presentation of that identity at a rate of 6 images per second (6 Hz) over 10 sec. Subsequently, this identity is presented in alternation with another facial identity (i.e., its anti-face, both faces being equidistant from an average face), producing an identity repetition rate of 3 Hz over a 20 sec testing sequence. A clear EEG response at 3 Hz is observed over the right occipito-temporal (ROT) cortex, indexing discrimination between the two facial identities in the absence of an explicit behavioral discrimination measure. This face identity discrimination occurs immediately after adaptation and disappears rapidly within 20 sec. Importantly, this 3 Hz response is not observed in a control condition without the single-identity 10 sec adaptation period. These results indicate that visual adaptation to a given facial identity produces an objective (i.e., at a pre-defined stimulation frequency) electrophysiological index of visual discrimination between that identity and another, and provides a unique behavior-free quantification of the effect of visual adaptation. PMID:26875725

  18. [Effect of the inhalation ++ anesthetic isoflurane on heart electrophysiology].

    PubMed

    Sarrión Auñón, J; Chorro Gascó, F J; Negueruela Cardo, A; Burguera Pérez, M; Sanchis Forés, J; Chuliá Campos, V; Palanca Sanfrancisco, J M; Such Belenguer, L; López Merino, V

    1992-01-01

    In two groups, A and B, both composed of 10 mongrel dogs, we studied the cardiac electrophysiologic effects of 1 and 1.5 MAC isoflurane administered by liquid injection in a closed circuit. In group B the study was done under pharmacological autonomic blockade (AB). With electrode catheters for programmed pacing and endocavitary potential recordings, we determined during the anesthesia with 1 and 1.5 MAC isoflurane: RR, spontaneous and paced AH, and HV intervals, corrected sinus recovery time (CSRT), Wenckebach point (WP), functional and effective refractory periods of atria (AFRP, AERP) and AV node (AVNFRP, AVNERP), and ventricular effective refractory period (VERP), these were compared to the ones obtained with a previous thiopental control. In group A, 1 MAC isoflurane increased over control: AERP and AH interval (p < 0.05), AFRP (p < 0.005), RR and AH paced intervals, WP, AVNFRP and VERP (p < 0.001), adding to these CSRT (p < 0.01) in 1.5 CAM. This level did not show differences with 1 MAC. In group B, 1 MAC isoflurane increased over control: AH (p < 0.05), RR, paced AH intervals, WP and AVNFRP (p < 0.001), adding to these AFRP and AERP (p < 0.05) in 1.5 MAC. This level increased with regard to 1 MAC: AFRP, AERP, AH paced interval and AVNERP (p < 0.05), and AVNFRP (p < 0.005). Isoflurane alone or with AB increased parameters of sinusal automaticity, atrial refractoriness, AV nodal conduction and refractoriness, increasing only without AB ventricular refractoriness and CSRT. With AB atrial and AV nodal refractoriness increased in an anesthetic depth dependent way. PMID:1439071

  19. Aldosterone-induced glycoproteins: electrophysiological-biochemical correlation.

    PubMed

    Szerlip, H M; Weisberg, L; Geering, K; Rossier, B C; Cox, M

    1988-05-01

    Aldosterone induces the synthesis of a group of glycoproteins (GP65,70) in toad urinary bladders which are potential effectors of the natriferic action of this hormone. In the present study we have confirmed that aldosterone produces a two-phase electrophysiological response. During the early phase (less than 3 h) short-circuit current and transepithelial conductance increase in parallel, while during the late phase (greater than 3 h) short-circuit current continues to increase without any further change in conductance. By biosynthetically labeling aldosterone-treated toad bladders with [35S]methionine either during the early (h 0-2 or 1-3) or the late (h 4-6 or 7-9) phases of the natriferic response, we have demonstrated that GP65,70 is synthesized as a late effect of aldosterone. Since synthesis of GP65,70 occurs at a time when the electromotive force of the Na+ pump is increasing, and since GP65,70 biochemically resembles the beta subunit of Na+/K+-ATPase, studies were undertaken to examine whether GP65,70 is the beta subunit. Purified amphibian renal beta subunit was analyzed by two-dimensional polyacrylamide gel electrophoresis and was found to have an isoelectric point and Mr value similar to those of GP65,70. However, when nitrocellulose blots containing wheat germ agglutinin-purified proteins from aldosterone-treated bladders were stained with monospecific polyclonal antibodies developed against the beta subunit, GP65,70 was not recognized, whereas a group of slightly more acidic proteins of similar Mr were recognized. Thus, GP65,70 is not the beta subunit of Na+/Ka+-ATPase. Further studies are needed to determine the cellular function of GP65,70. PMID:2835098

  20. Cardiac electrophysiologic effects of a new calcium antagonist, lacidipine.

    PubMed

    Cerbai, E; DeBonfioli Cavalcabó, P; Masini, I; Visentin, S; Giotti, A; Mugelli, A

    1990-04-01

    Lacidipine is a new 1,4-dihydropyridine derivative with potent and long-lasting antihypertensive activity. We used intracellular microelectrodes to characterize the electrophysiologic properties of lacidipine on different cardiac preparations. Lacidipine (10(-8) -10(-6) M) dose-dependently decreased contractility of driven sheep Purkinje fibers. For concentrations less than or equal to 10(-7) M, this effect was associated with a selective decrease of the plateau height. Higher concentrations (3 X 10(-7) and 10(-6) M), however, affected action potential amplitude, overshoot, and maximum rate of depolarization. In the same range of concentrations, lacidipine did not affect normal automaticity of guinea-pig sinus node and sheep Purkinje fibers. Lacidipine (10(-6) M) consistently blocked barium-induced abnormal automaticity in Purkinje fibers and reduced the amplitude and Vmax of the slow action potentials induced by histamine (10(-5) M) in guinea pig papillary muscle depolarized by potassium (22 mM). The effect of lacidipine on the slow inward current (Isi) was studied in shortened Purkinje fibers under voltage-clamp conditions. Lacidipine (10(-7)-10(-6) M) reduced the Isi without affecting the I-V relationship. None of the effects of lacidipine was reversed by 2-h washout. The results indicate that lacidipine has calcium-antagonistic properties in cardiac tissues. Its cardiac effects occur at concentrations 100 times higher than those active in the vascular smooth muscle. The lack of recovery of the lacidipine effects suggests that its interaction with the calcium channel may occur at an inner site of the cell membrane. PMID:1691391

  1. Electrophysiological and Anatomical Correlates of Spinal Cord Optical Coherence Tomography.

    PubMed

    Giardini, Mario E; Zippo, Antonio G; Valente, Maurizio; Krstajic, Nikola; Biella, Gabriele E M

    2016-01-01

    Despite the continuous improvement in medical imaging technology, visualizing the spinal cord poses severe problems due to structural or incidental causes, such as small access space and motion artifacts. In addition, positional guidance on the spinal cord is not commonly available during surgery, with the exception of neuronavigation techniques based on static pre-surgical data and of radiation-based methods, such as fluoroscopy. A fast, bedside, intraoperative real-time imaging, particularly necessary during the positioning of endoscopic probes or tools, is an unsolved issue. The objective of our work, performed on experimental rats, is to demonstrate potential intraoperative spinal cord imaging and probe guidance by optical coherence tomography (OCT). Concurrently, we aimed to demonstrate that the electromagnetic OCT irradiation exerted no particular effect at the neuronal and synaptic levels. OCT is a user-friendly, low-cost and endoscopy-compatible photonics-based imaging technique. In particular, by using a Fourier-domain OCT imager, operating at 850 nm wavelength and scanning transversally with respect to the spinal cord, we have been able to: 1) accurately image tissue structures in an animal model (muscle, spine bone, cerebro-spinal fluid, dura mater and spinal cord), and 2) identify the position of a recording microelectrode approaching and inserting into the cord tissue 3) check that the infrared radiation has no actual effect on the electrophysiological activity of spinal neurons. The technique, potentially extendable to full three-dimensional image reconstruction, shows prospective further application not only in endoscopic intraoperative analyses and for probe insertion guidance, but also in emergency and adverse situations (e.g. after trauma) for damage recognition, diagnosis and fast image-guided intervention. PMID:27050096

  2. [Characteristics of general anesthesia in the investigation of heart electrophysiology].

    PubMed

    Narbutas, Kestutis; Lekas, Raimundas; Rimkiene, Aldona; Civinskiene, Genuvaite

    2002-01-01

    Investigating electrophysiological properties of the heart under acute experimental conditions, dogs are affected by operative stress because of traumatic surgical manipulations, so investigations are performed under general anaesthesia. Many anaesthetics together with their main function have desintegrating influence on autonomic regulation mechanisms. That is why anaesthetics used during experiments must fullfil such requirement--have minimal influence on autonomic nervous system (ANS) and heart conductivity system (HCS) interaction parameters or to make this influence insignificant. We did not found common anaesthesia methodics that can fullfil that requirements, so we decided to prepare new common anaesthesia methodics, which could fullfil requirements mentioned above. We choose medicaments according to their pharmacokinetics and pharmacodynamics action. For methodics optimization we've used 2 groups of dogs (mongrel dogs males weight 7-15 kg) (n = 10). We've applied different anaesthesia schemas on each group. Premedication in the I-st group was performed with intramuscle (i.m.) combination of diazepam, ketamine and phentanyl and for anaesthesia continuous intravenous (i.v.) infusion of thiopental and ketamine. In II-nd group premedication was performed with i.m. injection of ketamine/phentanyl combination and for anaesthesia--continuous i.v. infusion of thiopental. Induction in both groups was performed with i.v. thiopental injection. Suitability of premedication and anaesthesia was valued by adequativity of haemodynamics (heart rate 1/min) and surgical manipulations during experiments. Our conclusion is: investigating interaction of ANS and HCS methodics used in the I-st group of dogs is more suitable. PMID:12474758

  3. Electrophysiologic changes in patients with untreated primary hypothyroidism.

    PubMed

    Eslamian, Fariba; Bahrami, Amir; Aghamohammadzadeh, Naser; Niafar, Mitra; Salekzamani, Yaghoub; Behkamrad, Keyvan

    2011-06-01

    Thyroid diseases may cause signs and symptoms of neuromuscular dysfunction. Hypothyroidism has been associated with the clinical features of proximal muscle weakness, mononeuropathy, and sensorimotor polyneuropathy. This study aimed at evaluating the electrophysiologic findings in patients with untreated spontaneous hypothyroidism and comparing them with a healthy control group. In a case-control cross-sectional study, 40 patients with definite diagnosis of clinical hypothyroidism and 40 healthy control subjects were evaluated by electromyography and nerve conduction studies in the specialized clinic of the Tabriz University of Medical Sciences during an 18-month period. Seven male and 33 female patients with a mean age of 39.5 ± 11.8 years were enrolled. In this group, there were 12 cases (30%) with clinical muscle weakness, with severity of approximately 4/5, 18 cases (45%) with decreased or absent deep tendon reflexes, 6 cases (15%) with neuropathy, including 4 sensory and 2 sensorimotor, of which 5 cases were mild and 1 case was moderate, 3 cases (7.5%) with myopathy, and 13 cases (32.5%) with carpal tunnel syndrome, which was mild in 7, moderate in 10, and severe in 2 hands. Patients with neuropathy were significantly older than those without neuropathy (P = 0.001). There was no significant relation between gender, duration of the disease, serum TSH level, and the presence of clinical muscle weakness with the occurrence of neuropathy or myopathy. Female gender, increasing age, duration of the disease, and the frequency of clinical weakness were, however, significantly related to the presence of carpal tunnel syndrome (P < 0.05). In conclusion, in patients with untreated primary hypothyroidism, majority had the carpal tunnel syndrome. Mild neuropathy mainly of sensory type and myopathy were uncommon and rare findings, respectively. Early treatment would hinder the progression of mentioned abnormalities and minimize their occurrence. PMID:21633261

  4. Evolving anatomic and electrophysiologic considerations associated with Fontan conversion.

    PubMed

    Mavroudis, Constantine; Backer, Carl Lewis; Deal, Barbara J; Stewart, Robert D; Franklin, Wayne H; Tsao, Sabrina; Ward, Kendra

    2007-01-01

    The principles of Fontan conversion with arrhythmia surgery are to restore the cardiac anatomy by converting the original atriopulmonary connection to a total cavopulmonary artery extracardiac connection and treat the underlying atrial arrhythmias. Successful outcomes of this procedure are dependent on a thorough understanding of several factors: the patient's fundamental diagnosis of single-ventricle anatomy, the resultant cardiac configuration from the original atriopulmonary Fontan connection, right atrial dilatation that leads to atrial flutter or fibrillation, and associated congenital cardiac anomalies. The purpose of this article is to present some of the more challenging anatomic and electrophysiologic problems we have encountered with Fontan conversion and arrhythmia surgery and the innovative solutions we have used to treat them. The cases reviewed herein include: takedown of a Bjork-Fontan modification, right ventricular hypertension and tricuspid regurgitation after atriopulmonary Fontan for pulmonary atresia and intact ventricular septum, takedown of atrioventricular valve isolation patch for right-sided maze procedure, resultant hemodynamic considerations leading to intraoperative pulmonary vein stenosis after Fontan conversion, unwanted inferior vena cava retraction during the extracardiac connection, right atrial cannulation in the presence of a right atrial clot, distended left superior vena cava causing left pulmonary vein stenosis, dropped atrial septum, and the modified right-sided maze procedure for various single-ventricle pathology. Since 1994 we have performed Fontan conversion with arrhythmia surgery on 109 patients with a 0.9% mortality rate. We attribute our program's success in no small measure to the strong collaborative efforts of the cardiothoracic surgery and cardiology teams. PMID:17434005

  5. Electrophysiological correlates of melodic processing in congenital amusia.

    PubMed

    Omigie, Diana; Pearce, Marcus T; Williamson, Victoria J; Stewart, Lauren

    2013-08-01

    Music listening involves using previously internalized regularities to process incoming musical structures. A condition known as congenital amusia is characterized by musical difficulties, notably in the detection of gross musical violations. However, there has been increasing evidence that individuals with the disorder show preserved musical ability when probed using implicit methods. To further characterize the degree to which amusic individuals show evidence of latent sensitivity to musical structure, particularly in the context of stimuli that are ecologically valid, electrophysiological recordings were taken from a sample of amusic and control participants as they listened to real melodies. To encourage them to pay attention to the music, participants were asked to detect occasional notes in a different timbre. Using a computational model of auditory expectation to identify points of varying levels of expectedness in these melodies (in units of information content (IC), a measure which has an inverse relationship with probability), ERP analysis investigated the extent to which the amusic brain differs from that of controls when processing notes of high IC (low probability) as compared to low IC ones (high probability). The data revealed a novel effect that was highly comparable in both groups: Notes with high IC reliably elicited a delayed P2 component relative to notes with low IC, suggesting that amusic individuals, like controls, found these notes more difficult to evaluate. However, notes with high IC were also characterized by an early frontal negativity in controls that was attenuated in amusic individuals. A correlation of this early negative effect with the ability to make accurate note expectedness judgments (previous data collected from a subset of the current sample) was shown to be present in typical individuals but compromised in individuals with amusia: a finding in line with evidence of a close relationship between the amplitude of such a

  6. TraceContract

    NASA Technical Reports Server (NTRS)

    Kavelund, Klaus; Barringer, Howard

    2012-01-01

    TraceContract is an API (Application Programming Interface) for trace analysis. A trace is a sequence of events, and can, for example, be generated by a running program, instrumented appropriately to generate events. An event can be any data object. An example of a trace is a log file containing events that a programmer has found important to record during a program execution. Trace - Contract takes as input such a trace together with a specification formulated using the API and reports on any violations of the specification, potentially calling code (reactions) to be executed when violations are detected. The software is developed as an internal DSL (Domain Specific Language) in the Scala programming language. Scala is a relatively new programming language that is specifically convenient for defining such internal DSLs due to a number of language characteristics. This includes Scala s elegant combination of object-oriented and functional programming, a succinct notation, and an advanced type system. The DSL offers a combination of data-parameterized state machines and temporal logic, which is novel. As an extension of Scala, it is a very expressive and convenient log file analysis framework.

  7. 48 CFR 17.204 - Contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Contracts. 17.204 Section 17.204 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 17.204 Contracts. (a) The contract shall specify...

  8. 48 CFR 3417.204 - Contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Contracts. 3417.204... CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 3417.204 Contracts. (e) Except as otherwise provided by law, contract periods that exceed the five-year limitation specified in FAR...

  9. 48 CFR 716.406 - Contract clauses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Contract clauses. 716.406 Section 716.406 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Cost Reimbursement Contracts 716.406 Contract clauses....

  10. 48 CFR 417.204 - Contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Contracts. 417.204 Section 417.204 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 417.204 Contracts. The head of the contracting...

  11. 48 CFR 3417.204 - Contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Contracts. 3417.204... CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 3417.204 Contracts. (e) Except as otherwise provided by law, contract periods that exceed the five-year limitation specified in FAR...

  12. 48 CFR 2017.204 - Contracts

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Contracts 2017.204 Section 2017.204 Federal Acquisition Regulations System NUCLEAR REGULATORY COMMISSION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 2017.204 Contracts (a) The contracting officer...

  13. 48 CFR 2017.204 - Contracts

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Contracts 2017.204 Section 2017.204 Federal Acquisition Regulations System NUCLEAR REGULATORY COMMISSION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 2017.204 Contracts (a) The contracting officer...

  14. 48 CFR 3416.603 - Letter contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Letter contracts. 3416.603... CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Time-and-Materials, Labor-Hour, and Letter Contracts 3416.603 Letter contracts....

  15. 48 CFR 2417.204 - Contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Contracts. 2417.204... CONTRACTING METHODS AND CONTRACTING TYPES SPECIAL CONTRACTING METHODS Options 2417.204 Contracts. (e)(1) The Senior Procurement Executive (SPE) is authorized to approve contract periods for other than...

  16. 48 CFR 817.204 - Contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Contracts. 817.204 Section 817.204 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 817.204 Contracts. (a) The contracting officer...

  17. 48 CFR 3417.204 - Contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Contracts. 3417.204 Section... CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 3417.204 Contracts. (e) Except as otherwise provided by law, contract periods that exceed the five-year limitation specified in FAR...

  18. 48 CFR 817.204 - Contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Contracts. 817.204 Section 817.204 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 817.204 Contracts. (a) The contracting officer...

  19. 48 CFR 3016.603 - Letter contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Letter contracts. 3016.603... ACQUISITION REGULATION (HSAR) CONTRACT METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Time-and-Materials, Labor-Hour, and Letter Contracts 3016.603 Letter contracts....

  20. 48 CFR 1817.204 - Contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Contracts. 1817.204... CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 1817.204 Contracts. (e)(i) The 5-year limitation (basic plus option periods) applies to all NASA contracts regardless of type and...

  1. 48 CFR 17.204 - Contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Contracts. 17.204 Section 17.204 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 17.204 Contracts. (a) The contract shall specify...

  2. 48 CFR 2017.204 - Contracts

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Contracts 2017.204 Section 2017.204 Federal Acquisition Regulations System NUCLEAR REGULATORY COMMISSION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 2017.204 Contracts (a) The contracting officer...

  3. 48 CFR 4.103 - Contract clause.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Contract clause. 4.103... MATTERS Contract Execution 4.103 Contract clause. The contracting officer shall insert the clause at 52.204-1, Approval of Contract, in solicitations and contracts if required by agency procedures....

  4. 48 CFR 1817.204 - Contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Contracts. 1817.204... CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 1817.204 Contracts. (e)(i) The 5-year limitation (basic plus option periods) applies to all NASA contracts regardless of type and...

  5. 48 CFR 817.204 - Contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Contracts. 817.204 Section 817.204 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 817.204 Contracts. (a) The contracting officer...

  6. 48 CFR 16.307 - Contract clauses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Contract clauses. 16.307 Section 16.307 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Cost-Reimbursement Contracts 16.307 Contract clauses. (a)(1)...

  7. 48 CFR 2017.204 - Contracts

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Contracts 2017.204 Section 2017.204 Federal Acquisition Regulations System NUCLEAR REGULATORY COMMISSION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 2017.204 Contracts (a) The contracting officer...

  8. 48 CFR 3417.204 - Contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Contracts. 3417.204... CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 3417.204 Contracts. (e) Except as otherwise provided by law, contract periods that exceed the five-year limitation specified in FAR...

  9. 48 CFR 817.204 - Contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Contracts. 817.204 Section 817.204 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 817.204 Contracts. (a) The contracting officer...

  10. 48 CFR 1817.204 - Contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Contracts. 1817.204... CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 1817.204 Contracts. (e)(i) The 5-year limitation (basic plus option periods) applies to all NASA contracts regardless of type and...

  11. 48 CFR 2417.204 - Contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Contracts. 2417.204... CONTRACTING METHODS AND CONTRACTING TYPES SPECIAL CONTRACTING METHODS Options 2417.204 Contracts. (e) The Senior Procurement Executive shall approve any solicitation or contract which exceeds the five (5)...

  12. 48 CFR 417.204 - Contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Contracts. 417.204 Section 417.204 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 417.204 Contracts. The head of the contracting...

  13. 48 CFR 16.302 - Cost contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Cost contracts. 16.302 Section 16.302 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Cost-Reimbursement Contracts 16.302 Cost contracts....

  14. 48 CFR 16.406 - Contract clauses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Contract clauses. 16.406 Section 16.406 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Incentive Contracts 16.406 Contract clauses. (a) Insert...

  15. 48 CFR 1817.204 - Contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Contracts. 1817.204... CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 1817.204 Contracts. (e)(i) The 5-year limitation (basic plus option periods) applies to all NASA contracts regardless of type and...

  16. 48 CFR 2417.204 - Contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Contracts. 2417.204... CONTRACTING METHODS AND CONTRACTING TYPES SPECIAL CONTRACTING METHODS Options 2417.204 Contracts. (e)(1) The Senior Procurement Executive (SPE) is authorized to approve contract periods for other than...

  17. 48 CFR 3417.70 - Modular contracting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Modular contracting. 3417... REGULATION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Modular Contracting 3417.70 Modular contracting. (a) FSA—May incrementally conduct successive procurements of modules of...

  18. 48 CFR 2417.204 - Contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Contracts. 2417.204... CONTRACTING METHODS AND CONTRACTING TYPES SPECIAL CONTRACTING METHODS Options 2417.204 Contracts. (e) The Senior Procurement Executive shall approve any solicitation or contract which exceeds the five (5)...

  19. 48 CFR 17.204 - Contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Contracts. 17.204 Section 17.204 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 17.204 Contracts. (a) The contract shall specify...

  20. 48 CFR 17.204 - Contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Contracts. 17.204 Section 17.204 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 17.204 Contracts. (a) The contract shall specify...

  1. 48 CFR 17.109 - Contract clauses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Contract clauses. 17.109 Section 17.109 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Multiyear Contracting 17.109 Contract clauses. (a)...

  2. 48 CFR 417.204 - Contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Contracts. 417.204 Section 417.204 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 417.204 Contracts. The head of the contracting...

  3. 48 CFR 3437.670 - Contract type.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Contract type. 3437.670... SPECIAL CATEGORIES OF CONTRACTING SERVICE CONTRACTING Performance-Based Acquisition 3437.670 Contract type. Award-term contracting may be used for performance-based contracts and task orders that...

  4. 48 CFR 417.204 - Contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false Contracts. 417.204 Section 417.204 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 417.204 Contracts. The head of the contracting...

  5. 48 CFR 732.111 - Contract clauses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Contract clauses. 732.111... CONTRACTING REQUIREMENTS CONTRACT FINANCING General 732.111 Contract clauses. (a) (b) USAID may obtain short... indefinite quantity contracts that are a combination of contract types. Rather than using the...

  6. 48 CFR 4.802 - Contract files.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Contract files. 4.802 Section 4.802 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL ADMINISTRATIVE MATTERS Government Contract Files 4.802 Contract files. (a) A contract file should generally consist of— (1) The contracting office contract...

  7. 48 CFR 4.802 - Contract files.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Contract files. 4.802 Section 4.802 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL ADMINISTRATIVE MATTERS Government Contract Files 4.802 Contract files. (a) A contract file should generally consist of— (1) The contracting office contract...

  8. 48 CFR 937.7040 - Contract clauses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CONTRACTING SERVICE CONTRACTING Protective Services Contracting 937.7040 Contract clauses. The contracting officer shall insert the clause at 952.237-70 entitled “Collective bargaining agreements—protective services” in all protective services solicitations and contracts involving DOE-owned facilities...

  9. 48 CFR 937.7040 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACTING SERVICE CONTRACTING Protective Services Contracting 937.7040 Contract clauses. The contracting officer shall insert the clause at 952.237-70 entitled “Collective bargaining agreements—protective services” in all protective services solicitations and contracts involving DOE-owned facilities...

  10. 48 CFR 4.802 - Contract files.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Contract files. 4.802 Section 4.802 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL ADMINISTRATIVE MATTERS Government Contract Files 4.802 Contract files. (a) A contract file should generally consist of— (1) The contracting office contract...

  11. 48 CFR 1846.470 - Contract clause.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE Government Contract Quality Assurance 1846.470 Contract clause. The contracting officer may insert a clause substantially as stated at 1852.246-71, Government Contract Quality Assurance Functions, in solicitations and contracts to specify the location(s) of quality...

  12. 48 CFR 1846.470 - Contract clause.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE Government Contract Quality Assurance 1846.470 Contract clause. The contracting officer may insert a clause substantially as stated at 1852.246-71, Government Contract Quality Assurance Functions, in solicitations and contracts to specify the location(s) of quality...

  13. 48 CFR 1416.405 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract clauses. 1416.405 Section 1416.405 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Incentive Contracts 1416.405 Contract clauses. The BPC, without the...

  14. 48 CFR 817.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contracts. 817.204 Section 817.204 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 817.204 Contracts. (a) The contracting officer...

  15. 48 CFR 716.406 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract clauses. 716.406 Section 716.406 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Cost Reimbursement Contracts 716.406 Contract clauses....

  16. 48 CFR 1517.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contracts. 1517.204 Section 1517.204 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 1517.204 Contracts. The SCM may approve a contract...

  17. 48 CFR 2017.204 - Contracts

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contracts 2017.204 Section 2017.204 Federal Acquisition Regulations System NUCLEAR REGULATORY COMMISSION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 2017.204 Contracts (a) The contracting officer...

  18. 48 CFR 17.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contracts. 17.204 Section 17.204 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 17.204 Contracts. (a) The contract shall specify...

  19. 48 CFR 417.204 - Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Contracts. 417.204 Section 417.204 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE CONTRACTING METHODS AND CONTRACT TYPES SPECIAL CONTRACTING METHODS Options 417.204 Contracts. The head of the contracting...

  20. 48 CFR 732.111 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract clauses. 732.111... CONTRACTING REQUIREMENTS CONTRACT FINANCING General 732.111 Contract clauses. (a) (b) USAID may obtain short... indefinite quantity contracts that are a combination of contract types. Rather than using the...

  1. 48 CFR 916.307 - Contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract clauses. 916.307 Section 916.307 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Cost-Reimbursement Contracts 916.307 Contract clauses. (g) Insert...

  2. 48 CFR 935.071 - Contract clause.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Contract clause. 935.071... CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 935.071 Contract clause. The contracting officer must insert the clause at 952.235-71, Research Misconduct, in contracts, including management and...

  3. 48 CFR 4.802 - Contract files.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contract files. 4.802 Section 4.802 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL ADMINISTRATIVE MATTERS Government Contract Files 4.802 Contract files. (a) A contract file should generally consist of— (1) The contracting office contract...

  4. 48 CFR 32.611 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contract clause. 32.611 Section 32.611 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Debts 32.611 Contract clause. (a) The contracting officer shall...

  5. NeuroPigPen: A Scalable Toolkit for Processing Electrophysiological Signal Data in Neuroscience Applications Using Apache Pig.

    PubMed

    Sahoo, Satya S; Wei, Annan; Valdez, Joshua; Wang, Li; Zonjy, Bilal; Tatsuoka, Curtis; Loparo, Kenneth A; Lhatoo, Samden D

    2016-01-01

    The recent advances in neurological imaging and sensing technologies have led to rapid increase in the volume, rate of data generation, and variety of neuroscience data. This "neuroscience Big data" represents a significant opportunity for the biomedical research community to design experiments using data with greater timescale, large number of attributes, and statistically significant data size. The results from these new data-driven research techniques can advance our understanding of complex neurological disorders, help model long-term effects of brain injuries, and provide new insights into dynamics of brain networks. However, many existing neuroinformatics data processing and analysis tools were not built to manage large volume of data, which makes it difficult for researchers to effectively leverage this available data to advance their research. We introduce a new toolkit called NeuroPigPen that was developed using Apache Hadoop and Pig data flow language to address the challenges posed by large-scale electrophysiological signal data. NeuroPigPen is a modular toolkit that can process large volumes of electrophysiological signal data, such as Electroencephalogram (EEG), Electrocardiogram (ECG), and blood oxygen levels (SpO2), using a new distributed storage model called Cloudwave Signal Format (CSF) that supports easy partitioning and storage of signal data on commodity hardware. NeuroPigPen was developed with three design principles: (a) Scalability-the ability to efficiently process increasing volumes of data; (b) Adaptability-the toolkit can be deployed across different computing configurations; and (c) Ease of programming-the toolkit can be easily used to compose multi-step data processing pipelines using high-level programming constructs. The NeuroPigPen toolkit was evaluated using 750 GB of electrophysiological signal data over a variety of Hadoop cluster configurations ranging from 3 to 30 Data nodes. The evaluation results demonstrate that the toolkit

  6. NeuroPigPen: A Scalable Toolkit for Processing Electrophysiological Signal Data in Neuroscience Applications Using Apache Pig

    PubMed Central

    Sahoo, Satya S.; Wei, Annan; Valdez, Joshua; Wang, Li; Zonjy, Bilal; Tatsuoka, Curtis; Loparo, Kenneth A.; Lhatoo, Samden D.

    2016-01-01

    The recent advances in neurological imaging and sensing technologies have led to rapid increase in the volume, rate of data generation, and variety of neuroscience data. This “neuroscience Big data” represents a significant opportunity for the biomedical research community to design experiments using data with greater timescale, large number of attributes, and statistically significant data size. The results from these new data-driven research techniques can advance our understanding of complex neurological disorders, help model long-term effects of brain injuries, and provide new insights into dynamics of brain networks. However, many existing neuroinformatics data processing and analysis tools were not built to manage large volume of data, which makes it difficult for researchers to effectively leverage this available data to advance their research. We introduce a new toolkit called NeuroPigPen that was developed using Apache Hadoop and Pig data flow language to address the challenges posed by large-scale electrophysiological signal data. NeuroPigPen is a modular toolkit that can process large volumes of electrophysiological signal data, such as Electroencephalogram (EEG), Electrocardiogram (ECG), and blood oxygen levels (SpO2), using a new distributed storage model called Cloudwave Signal Format (CSF) that supports easy partitioning and storage of signal data on commodity hardware. NeuroPigPen was developed with three design principles: (a) Scalability—the ability to efficiently process increasing volumes of data; (b) Adaptability—the toolkit can be deployed across different computing configurations; and (c) Ease of programming—the toolkit can be easily used to compose multi-step data processing pipelines using high-level programming constructs. The NeuroPigPen toolkit was evaluated using 750 GB of electrophysiological signal data over a variety of Hadoop cluster configurations ranging from 3 to 30 Data nodes. The evaluation results demonstrate that

  7. Electrophysiological characterization of adult-onset Niemann-Pick type C disease.

    PubMed

    Iodice, Rosa; Dubbioso, Raffaele; Topa, Antonietta; Ruggiero, Lucia; Pisciotta, Chiara; Esposito, Marcello; Tozza, Stefano; Santoro, Lucio; Manganelli, Fiore

    2015-01-15

    In infantile and juvenile Niemann-Pick type C (NPC) disease electrophysiological studies have shown central (CNS) and peripheral (PNS) nervous system abnormalities. However, an extensive electrophysiological evaluation of CNS and PNS in adult form of NPC is still lacking. The aim of the study is to assess in adult-onset NPC disease the involvement of CNS and PNS by a multimodal electrophysiological approach. Three patients affected by adult form of NPC disease underwent electrophysiological evaluation including nerve conduction study (NCS), magnetic motor (MEPs), visual (VEPs), somatosensory (SSEPs) and brainstem auditory (BAEPs) evoked potentials. NCS, MEPs, VEPs and upper limb SSEPs were normal. Lower limb SSEPs were abnormal in all patients and abnormalities were consistent with a length-dependent process affecting the central somatosensory pathway. BAEPs were abnormal in all patients with both peripheral and central impairment of auditory pathway. Our electrophysiological findings suggest that auditory and lower limb somatosensory pathways are constantly affected in adult-onset form of NPC disease. The involvement of PNS, pyramidal, visual and upper limb somatosensory pathways might occur later during the course of disease. PMID:25537619

  8. Electrophysiological Motor Unit Number Estimation (MUNE) Measuring Compound Muscle Action Potential (CMAP) in Mouse Hindlimb Muscles.

    PubMed

    Arnold, W David; Sheth, Kajri A; Wier, Christopher G; Kissel, John T; Burghes, Arthur H; Kolb, Stephen J

    2015-01-01

    Compound muscle action potential (CMAP) and motor unit number estimation (MUNE) are electrophysiological techniques that can be used to monitor the functional status of a motor unit pool in vivo. These measures can provide insight into the normal development and degeneration of the neuromuscular system. These measures have clear translational potential because they are routinely applied in diagnostic and clinical human studies. We present electrophysiological techniques similar to those employed in humans to allow recordings of mouse sciatic nerve function. The CMAP response represents the electrophysiological output from a muscle or group of muscles following supramaximal stimulation of a peripheral nerve. MUNE is an electrophysiological technique that is based on modifications of the CMAP response. MUNE is a calculated value that represents the estimated number of motor neurons or axons (motor control input) supplying the muscle or group of muscles being tested. We present methods for recording CMAP responses from the proximal leg muscles using surface recording electrodes following the stimulation of the sciatic nerve in mice. An incremental MUNE technique is described using submaximal stimuli to determine the average single motor unit potential (SMUP) size. MUNE is calculated by dividing the CMAP amplitude (peak-to-peak) by the SMUP amplitude (peak-to-peak). These electrophysiological techniques allow repeated measures in both neonatal and adult mice in such a manner that facilitates rapid analysis and data collection while reducing the number of animals required for experimental testing. Furthermore, these measures are similar to those recorded in human studies allowing more direct comparisons. PMID:26436455

  9. A Quantitative Comparison of the Behavior of Human Ventricular Cardiac Electrophysiology Models in Tissue

    PubMed Central

    Elshrif, Mohamed M.; Cherry, Elizabeth M.

    2014-01-01

    Numerical integration of mathematical models of heart cell electrophysiology provides an important computational tool for studying cardiac arrhythmias, but the abundance of available models complicates selecting an appropriate model. We study the behavior of two recently published models of human ventricular action potentials, the Grandi-Pasqualini-Bers (GPB) and the O'Hara-Virág-Varró-Rudy (OVVR) models, and compare the results with four previously published models and with available experimental and clinical data. We find the shapes and durations of action potentials and calcium transients differ between the GPB and OVVR models, as do the magnitudes and rate-dependent properties of transmembrane currents and the calcium transient. Differences also occur in the steady-state and S1–S2 action potential duration and conduction velocity restitution curves, including a maximum conduction velocity for the OVVR model roughly half that of the GPB model and well below clinical values. Between single cells and tissue, both models exhibit differences in properties, including maximum upstroke velocity, action potential amplitude, and minimum diastolic interval. Compared to experimental data, action potential durations for the GPB and OVVR models agree fairly well (although OVVR epicardial action potentials are shorter), but maximum slopes of steady-state restitution curves are smaller. Although studies show alternans in normal hearts, it occurs only in the OVVR model, and only for a narrow range of cycle lengths. We find initiated spiral waves do not progress to sustained breakup for either model. The dominant spiral wave period of the GPB model falls within clinically relevant values for ventricular tachycardia (VT), but for the OVVR model, the dominant period is longer than periods associated with VT. Our results should facilitate choosing a model to match properties of interest in human cardiac tissue and to replicate arrhythmia behavior more closely. Furthermore, by

  10. Meta-analytical and electrophysiological evidence for executive dysfunction in primary dystonia.

    PubMed

    Lange, Florian; Seer, Caroline; Salchow, Carolin; Dengler, Reinhard; Dressler, Dirk; Kopp, Bruno

    2016-09-01

    Impaired motor control in primary dystonia has been linked to cortico-basal ganglia alterations that may also give rise to changes in executive functioning. However, no conclusive evidence for executive dysfunction in patients with primary dystonia has been reported yet. We conducted a meta-analysis of the relationship between primary dystonia and performance on the Wisconsin Card Sorting Test (WCST), an established test of executive functioning. Its results revealed a significant effect of medium size, indicating that primary dystonia is associated with moderate performance deficits on the WCST. Building on this finding, we conducted an event-related potential (ERP) study to elucidate the cognitive and neural mechanisms underlying executive dysfunction in primary dystonia. Eighteen patients with blepharospasm, a common form of primary focal dystonia, and 34 healthy matched controls completed a computerized version of the WCST. We specifically compared indicators of two distinct components of executive functioning: set shifting and rule inference. On a behavioral level, blepharospasm patients seemed to have particular difficulty integrating information to infer the correct task rule. In addition, P3a amplitude (as an electrophysiological marker of rule-inference processes) was selectively attenuated in blepharospasm patients. Executive dysfunction in blepharospasm can thus rather be attributed to a rule-inference deficit, whereas set-shifting abilities appear to be relatively unaffected by the disease. Moreover, P3a amplitude attenuation was related to disease duration, indicating that this ERP might serve as a neural indicator of disease progression and executive dysfunction in primary dystonia. These results demonstrate for the first time that pathophysiological alterations in primary dystonia might affect cortical activation for executive functioning. PMID:27376933

  11. Label-free Electrophysiological Cytometry for Stem Cell-Derived Cardiomyocyte Clusters

    PubMed Central

    Myers, Frank B.; Abilez, Oscar J.; Zarins, Christopher K.; Lee, Luke P.

    2012-01-01

    Stem cell therapies hold great promise for repairing tissues damaged due to disease or injury. However, a major obstacle facing this field is the difficulty in identifying cells of a desired phenotype from the heterogeneous population that arises during stem cell differentiation. Conventional fluorescence flow cytometry and magnetic cell purification require exogenous labeling of cell surface markers which can interfere with the performance of the cells of interest. Here, we describe a non-genetic, label-free cell cytometry method based on electrophysiological response to stimulus. As many of the cell types relevant for regenerative medicine are electrically-excitable (e.g. cardiomyocytes, neurons, smooth muscle cells), this technology is well-suited for identifying cells from heterogeneous stem cell progeny without the risk and expense associated with molecular labeling or genetic modification. Our label-free cell cytometer is capable of distinguishing clusters of undifferentiated human induced pluripotent stem cells (iPSC) from iPSC-derived cardiomyocyte (iPSC-CM) clusters. The system utilizes a microfluidic device with integrated electrodes for both electrical stimulation and recording of extracellular field potential (FP) signals from suspended cells in flow. The unique electrode configuration provides excellent rejection of field stimulus artifact while enabling sensitive detection of FPs with a noise floor of 2 μVrms. Cells are self-aligned to the recording electrodes via hydrodynamic flow focusing. Based on automated analysis of these extracellular signals, the system distinguishes cardiomyocytes from non-cardiomyocytes. This is an entirely new approach to cell cytometry, in which a cell’s functionality is assessed rather than its expression profile or physical characteristics. PMID:23207961

  12. A theoretical formulation of the electrophysiological inverse problem on the sphere

    NASA Astrophysics Data System (ADS)

    Riera, Jorge J.; Valdés, Pedro A.; Tanabe, Kunio; Kawashima, Ryuta

    2006-04-01

    The construction of three-dimensional images of the primary current density (PCD) produced by neuronal activity is a problem of great current interest in the neuroimaging community, though being initially formulated in the 1970s. There exist even now enthusiastic debates about the authenticity of most of the inverse solutions proposed in the literature, in which low resolution electrical tomography (LORETA) is a focus of attention. However, in our opinion, the capabilities and limitations of the electro and magneto encephalographic techniques to determine PCD configurations have not been extensively explored from a theoretical framework, even for simple volume conductor models of the head. In this paper, the electrophysiological inverse problem for the spherical head model is cast in terms of reproducing kernel Hilbert spaces (RKHS) formalism, which allows us to identify the null spaces of the implicated linear integral operators and also to define their representers. The PCD are described in terms of a continuous basis for the RKHS, which explicitly separates the harmonic and non-harmonic components. The RKHS concept permits us to bring LORETA into the scope of the general smoothing splines theory. A particular way of calculating the general smoothing splines is illustrated, avoiding a brute force discretization prematurely. The Bayes information criterion is used to handle dissimilarities in the signal/noise ratios and physical dimensions of the measurement modalities, which could affect the estimation of the amount of smoothness required for that class of inverse solution to be well specified. In order to validate the proposed method, we have estimated the 3D spherical smoothing splines from two data sets: electric potentials obtained from a skull phantom and magnetic fields recorded from subjects performing an experiment of human faces recognition.

  13. Hyperosmolar Tears Induce Functional and Structural Alterations of Corneal Nerves: Electrophysiological and Anatomical Evidence Toward Neurotoxicity

    PubMed Central

    Hirata, Harumitsu; Mizerska, Kamila; Marfurt, Carl F.; Rosenblatt, Mark I.

    2015-01-01

    Purpose In an effort to elucidate possible neural mechanisms underlying diminished tearing in dry eye disease, this study sought to determine if hyperosmolar tears, a ubiquitous sign of dry eye disease, produce functional changes in corneal nerve responses to drying of the cornea and if these changes correlate with alterations in corneal nerve morphology. Methods In vivo extracellular electrophysiological recordings were performed in rat trigeminal ganglion neurons that innervated the cornea before, and up to 3 hours after, the ocular application of continuous hyperosmolar tears or artificial tears. In corollary experiments, immunohistochemical staining was performed to compare corneal nerve morphology in control and in eyes treated with hyperosmolar solutions. Results Our previous studies identified a population of corneal afferents, dry-sensitive neurons that are strongly excited by corneal dessication (“dry response”), a response thought to trigger the lacrimation reflex. In the present study, we found that the dry responses of corneal dry-sensitive neurons were depressed or even completely abolished by hyperosmolar tears in a time- (30 minutes to 3 hours) and dose (450- to 1000-mOsm solutions)-dependent manner. Furthermore, eyes treated with hyperosmolar tears for 3 hours contained large numbers of morphologically abnormal (granular, fragmented, or prominently beaded) subbasal nerves that appeared to be undergoing degeneration. Conclusions These results demonstrate that tear hyperosmolarity, considered to be a “core” mechanism of dry eye disease, significantly decreases physiological sensitivity and morphologic integrity of the corneal nerves important in tear production. These alterations might contribute to the diminished tearing seen clinically in dry eye patients. PMID:26720465

  14. An electrooptical muscle contraction sensor.

    PubMed

    Chianura, Alessio; Giardini, Mario E

    2010-07-01

    An electrooptical sensor for the detection of muscle contraction is described. Infrared light is injected into the muscle, the backscattering is observed, and the contraction is detected by measuring the change, that occurs during muscle contraction, between the light scattered in the direction parallel and perpendicular to the muscle cells. With respect to electromyography and to optical absorption-based sensors, our device has the advantage of lower invasiveness, of lower sensitivity to electromagnetic noise and to movement artifacts, and of being able to distinguish between isometric and isotonic contractions. PMID:20490943

  15. Uterine Contraction Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Liu, Miao; Belfore, Lee A.; Shen, Yuzhong; Scerbo, Mark W.

    2010-01-01

    Building a training system for medical personnel to properly interpret fetal heart rate tracing requires developing accurate models that can relate various signal patterns to certain pathologies. In addition to modeling the fetal heart rate signal itself, the change of uterine pressure that bears strong relation to fetal heart rate and provides indications of maternal and fetal status should also be considered. In this work, we have developed a group of parametric models to simulate uterine contractions during labor and delivery. Through analysis of real patient records, we propose to model uterine contraction signals by three major components: regular contractions, impulsive noise caused by fetal movements, and low amplitude noise invoked by maternal breathing and measuring apparatus. The regular contractions are modeled by an asymmetric generalized Gaussian function and least squares estimation is used to compute the parameter values of the asymmetric generalized Gaussian function based on uterine contractions of real patients. Regular contractions are detected based on thresholding and derivative analysis of uterine contractions. Impulsive noise caused by fetal movements and low amplitude noise by maternal breathing and measuring apparatus are modeled by rational polynomial functions and Perlin noise, respectively. Experiment results show the synthesized uterine contractions can mimic the real uterine contractions realistically, demonstrating the effectiveness of the proposed algorithm.

  16. 48 CFR 235.006 - Contracting methods and contract type.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... award a fixed-price type contract for a development program effort unless— (1) The level of program risk... allocation of program risk between the Government and the contractor; and (3) A written determination that... contract for the lead ship of a class; (2) A reduction in the amount of work under a fixed-price...

  17. Electrophysiological characteristics of paroxysmal atrial fibrillation originating from superior vena cava: a clinical analysis of 30 cases.

    PubMed

    Shi, Xiang-Min; Yuan, Hong-Tao; Guo, Hong-Yang; Guo, Jian-Ping; Shan, Zhao-Liang; Wang, Yu-Tang

    2015-01-01

    To analyze characteristics of electrocardiogram (ECG), electrophysiological intracardiac mapping and radiofrequency ablation (RF) of paroxysmal atrial fibrillation (PAF) originating from superior vena cava (SVC), aiming to investigate electrophysiological characteristics of PAF with SVC origin. Clinical data of 30 subjects (18 men and 12 women, aged, 58.6 ± 15.5 years) with PAF of SVC origin were retrospectively analyzed; All patients underwent RF during 2006.9-2012.7. ECG of AF and atrial premature contractions (APCs), procedure and fluoroscopic time, numbers of ablation sites within SVC, complications and success rate were studied. Compared with P wave of sinus rhythm (SR), APCs of SVC origin exhibited higher amplitude in lead II (0.23 ± 0.11 vs. 0.15 ± 0.06 mv), III (0.19 ± 0.09 vs. 0.13 ± 0.08 mv), AVF (0.21 ± 0.13 vs. 0.14 ± 0.10 mv), V2 (0.24 ± 0.07 vs. 0.15 ± 0.09 mv) and V3 (0.21 ± 0.09 vs. 0.12 ± 0.05 mv) (P < 0.05), as well as more biphasic polarity in lead V1 (80.0% vs. 26.6%, P < 0.05) and isoelectric in AVL (60.0% vs. 6.7%, P < 0.05). In terms of left pulmonary vein (LPV) and right pulmonary vein (RPV) electrical isolation, procedure time (14.3 ± 11.5 vs. 33.7 ± 14.2, 28.1 ± 6.8 min, P < 0.05), fluoroscopic time (9.6 ± 3.8 vs. 21.1 ± 9.3, 19.4 ± 9.7 min, P < 0.05), ablation sites (11.2 ± 3.1 vs. 37.1 ± 13.7, 31.4 ± 10.4 points, P < 0.05) of SVC isolation (SVCI) remarkably decreased compared with that of mean LPV and RPV. After the procedure, 9 patients still presented paroxymal rapid firing within the SVC in the setting of SR restoration, 2 patients developed paroxysmal atrial flutter within 1 month after completion of ablation and were controlled by antiarrhythmic drugs. The APCs and AF of SVC origin manifested distinctive ECG features, which could be helpful to distinguish SVC from other foci before ablation, the completion of SVCI required shorter procedure and fluoroscopic time, as well as less ablation points, and meanwhile

  18. Electrophysiological, transcriptomic and morphologic profiling of single neurons using Patch-seq.

    PubMed

    Cadwell, Cathryn R; Palasantza, Athanasia; Jiang, Xiaolong; Berens, Philipp; Deng, Qiaolin; Yilmaz, Marlene; Reimer, Jacob; Shen, Shan; Bethge, Matthias; Tolias, Kimberley F; Sandberg, Rickard; Tolias, Andreas S

    2016-02-01

    Despite the importance of the mammalian neocortex for complex cognitive processes, we still lack a comprehensive description of its cellular components. To improve the classification of neuronal cell types and the functional characterization of single neurons, we present Patch-seq, a method that combines whole-cell electrophysiological patch-clamp recordings, single-cell RNA-sequencing and morphological characterization. Following electrophysiological characterization, cell contents are aspirated through the patch-clamp pipette and prepared for RNA-sequencing. Using this approach, we generate electrophysiological and molecular profiles of 58 neocortical cells and show that gene expression patterns can be used to infer the morphological and physiological properties such as axonal arborization and action potential amplitude of individual neurons. Our results shed light on the molecular underpinnings of neuronal diversity and suggest that Patch-seq can facilitate the classification of cell types in the nervous system. PMID:26689543

  19. Electrophysiological, transcriptomic and morphologic profiling of single neurons using Patch-seq

    PubMed Central

    Cadwell, Cathryn R; Palasantza, Athanasia; Jiang, Xiaolong; Berens, Philipp; Deng, Qiaolin; Yilmaz, Marlene; Reimer, Jacob; Shen, Shan; Bethge, Matthias; Tolias, Kimberley F; Sandberg, Rickard; Tolias, Andreas S

    2016-01-01

    Despite the importance of the mammalian neocortex for complex cognitive processes, we still lack a comprehensive description of its cellular components. To improve the classification of neuronal cell types and the functional characterization of single neurons, we present Patch-seq, a method that combines whole-cell electrophysiological patch-clamp recordings, single-cell RNA-sequencing and morphological characterization. Following electrophysiological characterization, cell contents are aspirated through the patch-clamp pipette and prepared for RNA-sequencing. Using this approach, we generate electrophysiological and molecular profiles of 58 neocortical cells and show that gene expression patterns can be used to infer the morphological and physiological properties such as axonal arborization and action potential amplitude of individual neurons. Our results shed light on the molecular underpinnings of neuronal diversity and suggest that Patch-seq can facilitate the classification of cell types in the nervous system. PMID:26689543

  20. Plant cell electrophysiology: applications in growth enhancement, somatic hybridisation and gene transfer.

    PubMed

    Ochatt, Sergio

    2013-12-01

    The use and exploitation of electrophysiology with plant cells have witnessed a slow but steady increase for a number of purposes in recent years. First envisaged only as a tool for the recovery of somatic hybrid plants following protoplast electrofusion, or for transient and/or stable genetic transformation following electroporation-mediated entry of foreign genes into protoplasts and cells, electrophysiological studies with plant cells and tissues have since spanned into other areas, and particularly for the assessment of the possible effects of electric and electromagnetic fields on the subsequent growth and differentiation competences of the electro-treated cells. This review will critically discuss these various applications of electrophysiology and will also aim at analysing the fundamental physiological and physico-chemical mechanisms underlying them. PMID:23562891

  1. Autonomous Head-mounted Electrophysiology Systems for Freely-Behaving Primates

    PubMed Central

    Nuyujukian, Paul; Foster, Justin; Shenoy, Krishna V.

    2011-01-01

    Recent technological advances have led to new lightweight battery-operated systems for electrophysiology. Such systems are head mounted, run for days without experimenter intervention, and can record and stimulate from single or multiple electrodes implanted in a freely-behaving primates. Here we discuss existing systems, studies that use them, and how they can augment traditional, physically restrained, “in-rig” electrophysiology. With existing technical capabilities these systems can acquire multiple signal classes, such as spikes, local field potential, and electromyography signals, and can stimulate based on real-time processing of recorded signals. Moving forward, this class of technologies, along with advances in neural signal processing and behavioral monitoring, have the potential to dramatically expand the scope and scale of electrophysiological studies. PMID:20655733

  2. Courtship Contract In Marital Therapy

    ERIC Educational Resources Information Center

    Goldberg, Carl

    1975-01-01

    The courtship contracts serve as conceptual frames of reference to understand the normative structure and the psychodynamic components in distress. The contract established during courtship is explored in order to develop, during the time of marital crisis, explicitly negotiated standards. The goal is to re-educate the spouses to meet each others'…

  3. Using Contracts in Premarital Counseling.

    ERIC Educational Resources Information Center

    Martin, Don; Medler, Byron

    1980-01-01

    The premarital contract is an effective tool in premarital counseling. This contract is a written or verbal agreement that makes more explicit one's attitudes and expectations about aspects that will influence the marital relationship. Topics include division of labor, employment, financial responsibility, and religious beliefs and practices.…

  4. Policing Mechanisms in Agricultural Contracts

    ERIC Educational Resources Information Center

    Wolf, Steven; Hueth, Brent; Ligon, Ethan

    2001-01-01

    In this paper we focus on mechanisms of coordination in agricultural contracts. Our approach is intended to advance understanding of social relations of production and distribution of power in agrofood systems. Through an analysis of contracts between farmers and intermediaries (e.g., processors, shippers, consignment agents) for California fruits…

  5. Two Views on Performance Contracting.

    ERIC Educational Resources Information Center

    Lurie, Sylvia; Smith, Kenneth

    1996-01-01

    North Chicago, Illinois, District 187, received a districtwide overhaul of lighting, heating, ventilation, and security systems through a 10-year performance contract with the Honeywell Corporation. The Briarcliff Manor Union-Free School District, New York, has a contract with Johnson Controls that guarantees a portion of the energy savings…

  6. Contract Training in Community Colleges.

    ERIC Educational Resources Information Center

    Suchorski, Joan M.

    One of the most significant developments in higher education over the past decade has been the increased linkages between colleges and other organizations and institutions. A prominent and fast-growing form of linkage is contract training. Contract training refers to an arrangement in which a business, a government agency, or a community…

  7. Contract Education: A Background Paper.

    ERIC Educational Resources Information Center

    California Community Colleges, Sacramento. Academic Senate.

    Today contract education is generally thought of as a program or course for which an employer is paying the full cost of instruction for customized training. Contract education can help faculty remain current, encourage industry to make equipment available to the college that might otherwise be too expensive, and provide employment opportunities…

  8. CONTRACT ADMINISTRATIVE TRACKING SYSTEM (CATS)

    EPA Science Inventory

    The Contract Administrative Tracking System (CATS) was developed in response to an ORD NHEERL, Mid-Continent Ecology Division (MED)-recognized need for an automated tracking and retrieval system for Cost Reimbursable Level of Effort (CR/LOE) Contracts. CATS is an Oracle-based app...

  9. 48 CFR 970.5232-8 - Integrated accounting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Solicitation Provisions and Contract Clauses for Management and Operating Contracts 970.5232-8 Integrated accounting. As prescribed in 970.3270(b... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Integrated accounting....

  10. 48 CFR 970.5232-8 - Integrated accounting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Solicitation Provisions and Contract Clauses for Management and Operating Contracts 970.5232-8 Integrated accounting. As prescribed in 970.3270(b... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Integrated accounting....

  11. 48 CFR 970.5232-8 - Integrated accounting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Solicitation Provisions and Contract Clauses for Management and Operating Contracts 970.5232-8 Integrated accounting. As prescribed in 970.3270(b... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Integrated accounting....

  12. 48 CFR 970.5232-8 - Integrated accounting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Solicitation Provisions and Contract Clauses for Management and Operating Contracts 970.5232-8 Integrated accounting. As prescribed in 970.3270(b... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Integrated accounting....

  13. 48 CFR 970.5232-8 - Integrated accounting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Solicitation Provisions and Contract Clauses for Management and Operating Contracts 970.5232-8 Integrated accounting. As prescribed in 970.3270(b... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Integrated accounting....

  14. Contractive multifunctions, fixed point inclusions and iterated multifunction systems

    NASA Astrophysics Data System (ADS)

    Kunze, H. E.; La Torre, D.; Vrscay, E. R.

    2007-06-01

    We study the properties of multifunction operators that are contractive in the Covitz-Nadler sense. In this situation, such operators T possess fixed points satisfying the relation x[set membership, variant]Tx. We introduce an iterative method involving projections that guarantees convergence from any starting point x0[set membership, variant]X to a point x[set membership, variant]XT, the set of all fixed points of a multifunction operator T. We also prove a continuity result for fixed point sets XT as well as a "generalized collage theorem" for contractive multifunctions. These results can then be used to solve inverse problems involving contractive multifunctions. Two applications of contractive multifunctions are introduced: (i) integral inclusions and (ii) iterated multifunction systems.

  15. Strategies and Lessons-Learned for the Successful Alignment of Contract Cost with the Contract Budget Base (CBB) within the First Year of Contract Award - 13154

    SciTech Connect

    Mullis, Jay; Rueter, Ken

    2013-07-01

    In order to provide a sound basis and foundation for integrated Project and Contract change management, it is imperative to ensure the alignment of the Negotiated Contract Costs (NCC) with the Contract Budget Base (CBB), where CBB is defined as the Performance Measurement Baseline (PMB) plus Management Reserve (MR). The achievement of this alignment assures customer and contractor agreement on scope, requirements, quantities, schedule and cost, which facilitates the identification of change conditions and ultimate agreement on the value of changes to the NCC and the CBB. Delays in contract/CBB true up/reconciliation can negatively effect measurement of project progress, limiting owner understanding of liability, and may result in increased contract disagreements and potential claims. The Department of Energy Oak Ridge Office of Environmental Management (OR-EM) and URS - CH2M Oak Ridge LLC (UCOR) achieved alignment of the NCC with the CBB within 10 months of UCOR taking over work on the East Tennessee Technology Park (ETTP) cleanup contract by: 1. Managing as a discrete project; 2. Establishing expectations and setting tone of interactions; 3. Using personnel experienced with Federal Acquisition Regulation (FAR); 4. Partnering; 5. Establishing ombudsmen. (authors)

  16. A Review of Behavioural and Electrophysiological Studies on Auditory Processing and Speech Perception in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Haesen, Birgitt; Boets, Bart; Wagemans, Johan

    2011-01-01

    This literature review aims to interpret behavioural and electrophysiological studies addressing auditory processing in children and adults with autism spectrum disorder (ASD). Data have been organised according to the applied methodology (behavioural versus electrophysiological studies) and according to stimulus complexity (pure versus complex…

  17. Cartographic services contract...for everything geographic

    USGS Publications Warehouse

    U.S. Geological Survey

    2003-01-01

    The U.S. Geological Survey's (USGS) Cartographic Services Contract (CSC) is used to award work for photogrammetric and mapping services under the umbrella of Architect-Engineer (A&E) contracting. The A&E contract is broad in scope and can accommodate any activity related to standard, nonstandard, graphic, and digital cartographic products. Services provided may include, but are not limited to, photogrammetric mapping and aerotriangulation; orthophotography; thematic mapping (for example, land characterization); analog and digital imagery applications; geographic information systems development; surveying and control acquisition, including ground-based and airborne Global Positioning System; analog and digital image manipulation, analysis, and interpretation; raster and vector map digitizing; data manipulations (for example, transformations, conversions, generalization, integration, and conflation); primary and ancillary data acquisition (for example, aerial photography, satellite imagery, multispectral, multitemporal, and hyperspectral data); image scanning and processing; metadata production, revision, and creation; and production or revision of standard USGS products defined by formal and informal specification and standards, such as those for digital line graphs, digital elevation models, digital orthophoto quadrangles, and digital raster graphics.

  18. [Contracts including performance and management of uncertainty].

    PubMed

    Duru, G; Garassus, P; Auray, J-P

    2013-09-01

    Since many decades in France, the most important part of ambulatory health care expenditure is represented by drug consumption. By the fact, French patient is indeed the greatest world consumer of pharmaceuticals treatments. Therefore, the regulation authorities by successive strategies, attempt to limit or even restrict market access for new drugs in the health care sector secured by public social insurance coverage. Common objectives are to assess the reimbursement to scientific studies and to fix the price of therapeutics at an acceptable level for both industries and government. New trends try then to determine recently the drug price in a dual approach, as a component of global and effective contract, including performance and outcome. The first diffusion authorization is diffusion concerned, but this concept takes into account the eventual success of new produces in long-term survey. Signed for a fixed period as reciprocal partnership between regulation authorities and pharmaceutics industries, the contract integrates two dimensions of incertitude. The first one is represented by the strategy of new treatments development according to efficacy and adapted price, and the second one is linked to the result of diffusion and determines adapted rules if eventual non-respects of the previous engagement are registered. This paper discusses problems related to this new dimension of incertitude affected by conditional drug prices in market access strategy and the adapted follow-up of new treatment diffusion fixed by "outcome" contract between French regulation administration and pharmaceutics industries in our recent economic context. PMID:24075704

  19. [Risk of contracting HIV].

    PubMed

    Becerra, Valeria Peixoto; Gaspar, Maria Filomena M; Alves, Maria Do Socorro C F

    2009-04-01

    The authors identify social activities related to the risk of contracting HIV in nursing students, bearing in mind their influence while using bio-secure methods, by means of an exploratory and qualitative study; 168 Superior School of Nursing in Lisbon, Portugal students participated in this study. Data were gathered by means of a Free Association Word Test which includes social demographic variables related to the participants. 90% of the 168 students in this study were female and 10% male. The majority 79,2%, of the participants age fell between 21 and 25 years and 97,6% of these participants were Portuguese. In the free association word test when responding to the stimulus HIV/AIDS, participants expressed disease (which is contagious in a clinical setting), and death as the awaited outcome for it. For the test term "risk of contagion when dealing with an AIDS patient" the participants often mentioned the words protection against contagion, as well as fear to contact blood and gloves as the main prevention method. To the stimulus measures of bio-security the words most frequently cited were glove as a protective measure in the context of professional activity and preservative (condom) to avoid contagion in other social contexts experienced by the participants. PMID:19554898

  20. INFINITY construction contract signed

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Key state and community leaders celebrated April 6 with the signing of a construction contract for the state-of-the-art INFINITY Science Center planned near John C. Stennis Space Center in south Mississippi. Gulfport Mayor George Schloegel (l to r), chair of non-profit INFINITY Science Center Inc., was joined for the signing ceremony at the Hancock Bank in Gulfport by Virginia Wagner, sister of late Hancock Bank President Leo Seal Jr.; and Roy Anderson III, president and CEO of Roy Anderson Corp. Seal was the first chair of INFINITY Science Center Inc., which has led in development of the project. Roy Anderson Corp. plans to begin construction on the 72,000-square-foot, $28 million science and education center in May. The Mississippi Department of Transportation (MDOT) also is set to begin construction of a $2 million access road to the new center. The April 6 ceremony was attended by numerous officials, including former Stennis Space Center Directors Jerry Hlass and Roy Estess; Mississippi Senate President Pro Tempore Billy Hewes, R-Gulfport; Mississippi Rep. Diane Peranich, D-Pass Christian; and MDOT Southern District Commissioner Wayne Brown.