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Sample records for bowel slow wave

  1. Fast wave current drive above the slow wave density limit

    International Nuclear Information System (INIS)

    McWilliams, R.; Sheehan, D.P.; Wolf, N.S.; Edrich, D.

    1989-01-01

    Fast wave and slow wave current drive near the mean gyrofrequency were compared in the Irvine Torus using distinct phased array antennae of similar principal wavelengths, frequencies, and input powers. The slow wave current drive density limit was measured for 50ω ci ≤ω≤500ω ci and found to agree with trends in tokamaks. Fast wave current drive was observed at densities up to the operating limit of the torus, demonstrably above the slow wave density limit

  2. Light storage via slow-light four-wave mixing

    International Nuclear Information System (INIS)

    Fan, Yun-Fei; Wang, Hai-Hua; Wei, Xiao-Gang; Li, Ai-Jun; Kang, Zhi-Hui; Wu, Jin-Hui; Zhang, Han-Zhuang; Xu, Huai-Liang; Gao, Jin-Yue

    2012-01-01

    We experimentally demonstrate a light storage via slow-light four-wave mixing in a solid-state medium with a four-level double lambda scheme. Using slow light based on electromagnetically induced transparency, we obtain a slowed four-wave mixing signal pulse together with the slowed probe pulse. During the propagation of light pulses, the storage and retrieval of both the slowed four-wave mixing pulse and the slowed probe pulse are studied by manipulating the intensities of the control fields. -- Highlights: ► A light storage via slow-light four-wave mixing is observed in a solid. ► The probe pulse is slowed under electromagnetically induced transparency. ► A slowed four-wave mixing pulse is obtained by slow light. ► The storage of slowed double pulses is studied.

  3. Application of Planar Broadband Slow-Wave Systems

    Directory of Open Access Journals (Sweden)

    Edvardas Metlevskis

    2012-04-01

    Full Text Available Different types of planar broadband slow-wave systems are used for designing microwave devices. The papers published by Lithuanian scientists analyze and investigate the models of helical and meander slow-wave systems. The article carefully examines the applications of meander slow-wave systems and presents the areas where similar systems, e.g. mobile devices, RFID, wireless technologies are used and reviewed nowadays. The paper also focuses on the examples of the papers discussing antennas, filters and couplers that contain designed and fabricated meander slow-wave systems.Article in Lithuanian

  4. Slow wave cyclotron maser

    International Nuclear Information System (INIS)

    Kho, T.H.; Lin, A.T.

    1988-01-01

    Cyclotron masers such as Gyrotrons and the Autoresonance Masers, are fast wave devices: the electromagnetic wave's phase velocity v rho , is greater than the electron beam velocity, v b . To be able to convert the beam kinetic energy into radiation in these devices the beam must have an initial transverse momentum, usually obtained by propagating the beam through a transverse wiggler magnet, or along a nonuniform guide magnetic field before entry into the interaction region. Either process introduces a significant amount of thermal spread in the beam which degrades the performance of the maser. However, if the wave phase velocity v rho v b , the beam kinetic energy can be converted directly into radiation without the requirement of an initial transverse beam momentum, making a slow wave cyclotron maser a potentially simpler and more compact device. The authors present the linear and nonlinear physics of the slow wave cyclotron maser and examine its potential for practical application

  5. Capillary waves in slow motion

    International Nuclear Information System (INIS)

    Seydel, Tilo; Tolan, Metin; Press, Werner; Madsen, Anders; Gruebel, Gerhard

    2001-01-01

    Capillary wave dynamics on glycerol surfaces has been investigated by means of x-ray photon correlation spectroscopy performed at grazing angles. The measurements show that thermally activated capillary wave motion is slowed down exponentially when the sample is cooled below 273 K. This finding directly reflects the freezing of the surface waves. The wave-number dependence of the measured time constants is in quantitative agreement with theoretical predictions for overdamped capillary waves

  6. Slow Wave Propagation and Sheath Interaction for ICRF Waves in the Tokamak SOL

    International Nuclear Information System (INIS)

    Myra, J. R.; D'Ippolito, D. A.

    2009-01-01

    In previous work we studied the propagation of slow-wave resonance cones launched parasitically by a fast-wave antenna into a tenuous magnetized plasma. Here we extend the previous calculation to ''dense'' scrape-off-layer (SOL) plasmas where the usual slow wave is evanescent. Using the sheath boundary condition, it is shown that for sufficiently close limiters, the slow wave couples to a sheath plasma wave and is no longer evanescent, but radially propagating. A self-consistent calculation of the rf-sheath width yields the resulting sheath voltage in terms of the amplitude of the launched SW, plasma parameters and connection length.

  7. Enhancement of sleep slow waves: underlying mechanisms and practical consequences.

    Directory of Open Access Journals (Sweden)

    Michele eBellesi

    2014-10-01

    Full Text Available Even modest sleep restriction, especially the loss of sleep slow wave activity, is invariably associated with slower EEG activity during wake, the occurrence of local sleep in an otherwise awake brain, and impaired performance due to cognitive and memory deficits. Recent studies not only confirm the beneficial role of sleep in memory consolidation, but also point to a specific role for sleep slow waves. Thus, the implementation of methods to enhance sleep slow waves without unwanted arousals or lightening of sleep could have significant practical implications. Here we first review the evidence that it is possible to enhance sleep slow waves in humans using transcranial direct-current stimulation and transcranial magnetic stimulation. Since these methods are currently impractical and their safety is questionable, especially for chronic long-term exposure, we then discuss novel data suggesting that it is possible to enhance slow waves using sensory stimuli. We consider the physiology of the K-complex, a peripheral evoked slow wave, and show that, among different sensory modalities, acoustic stimulation is the most effective in increasing the magnitude of slow waves, likely through the activation of non-lemniscal ascending pathways to the thalamo-cortical system. In addition, we discuss how intensity and frequency of the acoustic stimuli, as well as exact timing and pattern of stimulation, affect sleep enhancement. Finally, we discuss automated algorithms that read the EEG and, in real-time, adjust the stimulation parameters in a closed-loop manner to obtain an increase in sleep slow waves and avoid undesirable arousals. In conclusion, while discussing the mechanisms that underlie the generation of sleep slow waves, we review the converging evidence showing that acoustic stimulation is safe and represents an ideal tool for slow wave sleep enhancement.

  8. Soliton wave-speed management: Slowing, stopping, or reversing a solitary wave

    Science.gov (United States)

    Baines, Luke W. S.; Van Gorder, Robert A.

    2018-06-01

    While dispersion management is a well-known tool to control soliton properties such as shape or amplitude, far less effort has been directed toward the theoretical control of the soliton wave speed. However, recent experiments concerning the stopping or slowing of light demonstrate that the control of the soliton wave speed is of experimental interest. Motivated by these and other studies, we propose a management approach for modifying the wave speed of a soliton (or of other nonlinear wave solutions, such as periodic cnoidal waves) under the nonlinear Schrödinger equation. Making use of this approach, we are able to slow, stop, or even reverse a solitary wave, and we give several examples to bright solitons, dark solitons, and periodic wave trains, to demonstrate the method. An extension of the approach to spatially heterogeneous media, for which the wave may propagate differently at different spatial locations, is also discussed.

  9. Slow wave maturation on a visual working memory task.

    Science.gov (United States)

    Barriga-Paulino, Catarina I; Rodríguez-Martínez, Elena I; Rojas-Benjumea, Ma Ángeles; Gómez, Carlos M

    2014-07-01

    The purpose of the present study is to analyze how the Slow Wave develops in the retention period on a visual Delayed Match-to-Sample task performed by 170 subjects between 6 and 26 years old, divided into 5 age groups. In addition, a neuropsychological test (Working Memory Test Battery for Children) was correlated with this Event Related Potential (ERP) in order to observe possible relationships between Slow Wave maturation and the components of Baddeley and Hitch's Working Memory model. The results showed a slow negativity during the retention period in the posterior region in all the age groups, possibly resulting from sustained neural activity related to the visual item presented. In the anterior region, a positive slow wave was observed in the youngest subjects. Dipole analysis suggests that this fronto-central positivity in children (6-13 years old) consists of the positive side of the posterior negativity, once these subjects only needed two posterior dipoles to explain almost all the neural activity. Negative correlations were shown between the Slow Wave and the Working Memory Test Battery for Children, indicating a commonality in assessing Working Memory with the Slow Wave and the neuropsychological testing. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Human gamma oscillations during slow wave sleep.

    Directory of Open Access Journals (Sweden)

    Mario Valderrama

    Full Text Available Neocortical local field potentials have shown that gamma oscillations occur spontaneously during slow-wave sleep (SWS. At the macroscopic EEG level in the human brain, no evidences were reported so far. In this study, by using simultaneous scalp and intracranial EEG recordings in 20 epileptic subjects, we examined gamma oscillations in cerebral cortex during SWS. We report that gamma oscillations in low (30-50 Hz and high (60-120 Hz frequency bands recurrently emerged in all investigated regions and their amplitudes coincided with specific phases of the cortical slow wave. In most of the cases, multiple oscillatory bursts in different frequency bands from 30 to 120 Hz were correlated with positive peaks of scalp slow waves ("IN-phase" pattern, confirming previous animal findings. In addition, we report another gamma pattern that appears preferentially during the negative phase of the slow wave ("ANTI-phase" pattern. This new pattern presented dominant peaks in the high gamma range and was preferentially expressed in the temporal cortex. Finally, we found that the spatial coherence between cortical sites exhibiting gamma activities was local and fell off quickly when computed between distant sites. Overall, these results provide the first human evidences that gamma oscillations can be observed in macroscopic EEG recordings during sleep. They support the concept that these high-frequency activities might be associated with phasic increases of neural activity during slow oscillations. Such patterned activity in the sleeping brain could play a role in off-line processing of cortical networks.

  11. Role of biological membranes in slow-wave sleep.

    Science.gov (United States)

    Karnovsky, M L

    1991-02-01

    Two involvements of cellular membranes in slow-wave sleep (SWS) are discussed. In the first the endoplasmic reticulum (ER) is focussed upon, and in the second, the plasmalemma, where specific binding sites (receptors?) for promoters of slow-wave sleep are believed to be located. The study concerning the ER focuses on an enzyme in the brain, glucose-6-phosphatase, which, although present at low levels, manifests greatly increased activity during SWS compared to the waking state. The work on the plasmalemma has to do with the specific binding of muramyl peptides, inducers of slow-wave sleep, to various cells, and membrane preparations of various sorts, including those from brain tissue. Such cells as macrophages from mice, B-lymphocytes from human blood, and cells from a cell line (C-6 glioma) have been examined in this context.

  12. Optimizing detection and analysis of slow waves in sleep EEG.

    Science.gov (United States)

    Mensen, Armand; Riedner, Brady; Tononi, Giulio

    2016-12-01

    Analysis of individual slow waves in EEG recording during sleep provides both greater sensitivity and specificity compared to spectral power measures. However, parameters for detection and analysis have not been widely explored and validated. We present a new, open-source, Matlab based, toolbox for the automatic detection and analysis of slow waves; with adjustable parameter settings, as well as manual correction and exploration of the results using a multi-faceted visualization tool. We explore a large search space of parameter settings for slow wave detection and measure their effects on a selection of outcome parameters. Every choice of parameter setting had some effect on at least one outcome parameter. In general, the largest effect sizes were found when choosing the EEG reference, type of canonical waveform, and amplitude thresholding. Previously published methods accurately detect large, global waves but are conservative and miss the detection of smaller amplitude, local slow waves. The toolbox has additional benefits in terms of speed, user-interface, and visualization options to compare and contrast slow waves. The exploration of parameter settings in the toolbox highlights the importance of careful selection of detection METHODS: The sensitivity and specificity of the automated detection can be improved by manually adding or deleting entire waves and or specific channels using the toolbox visualization functions. The toolbox standardizes the detection procedure, sets the stage for reliable results and comparisons and is easy to use without previous programming experience. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Electron heating and current drive by mode converted slow waves

    International Nuclear Information System (INIS)

    Majeski, R.; Phillips, C.K.; Wilson, J.R.

    1994-01-01

    An approach to obtaining efficient single pass mode conversion at high parallel wave number from the fast magnetosonic wave to the slow ion Bernstein wave, in a two-ion species tokamak plasma, is described. The intent is to produce localized electron heating or current drive via the mode converted slow wave. In particular, this technique can be adapted to off-axis current drive for current profile control. Modeling for the case of deuterium-tritium plasmas in TFTR is presented

  14. Analysis of waves in the plasma guided by a periodical vane-type slow wave structure

    International Nuclear Information System (INIS)

    Wu, T.J.; Kou, C.S.

    2005-01-01

    In this study, the dispersion relation has been derived to characterize the propagation of the waves in the plasma guided by a periodical vane-type slow wave structure. The plasma is confined by a quartz plate. Results indicate that there are two different waves in this structure. One is the plasma mode that originates from the plasma surface wave propagating along the interface between the plasma and the quartz plate, and the other is the guide mode that originally travels along the vane-type slow wave structure. In contrast to its original slow wave characteristics, the guide mode becomes a fast wave in the low-frequency portion of the passband, and there exists a cut-off frequency for the guide mode. The vane-type guiding structure has been shown to limit the upper frequency of the passband of the plasma mode, compared with that of the plasma surface wave. In addition, the passband of the plasma mode increases with the plasma density while it becomes narrower for the guide mode. The influences of the parameters of the guiding structure and plasma density on the propagation of waves are also presented

  15. Wide-band slow-wave systems simulation and applications

    CERN Document Server

    Staras, Stanislovas

    2012-01-01

    The field of electromagnetics has seen considerable advances in recent years, based on the wide applications of numerical methods for investigating electromagnetic fields, microwaves, and other devices. Wide-Band Slow-Wave Systems: Simulation and Applications presents new technical solutions and research results for the analysis, synthesis, and design of slow-wave structures for modern electronic devices with super-wide pass-bands. It makes available, for the first time in English, significant research from the past 20 years that was previously published only in Russian and Lithuanian. The aut

  16. Electron heating and current drive by mode converted slow waves

    International Nuclear Information System (INIS)

    Majeski, R.; Phillips, C.K.; Wilson, J.R.

    1994-08-01

    An approach to obtaining efficient single pass mode conversion at high parallel wavenumber from the fast magnetosonic wave to the slow ion Bernstein wave, in a two ion species tokamak plasma, is described. The intent is to produce localized electron heating or current drive via the mode converted slow wave. In particular, this technique can be adapted to off-axis current drive for current profile control. Modelling for the case of deuterium-tritium plasmas in TFTR is presented

  17. SLOW MAGNETOACOUSTIC WAVES OBSERVED ABOVE A QUIET-SUN REGION IN A DARK CAVITY

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jiajia; Zhou Zhenjun; Wang Yuming; Liu Rui; Liao Chijian; Shen Chenglong; Zheng Huinan; Miao Bin; Su Zhenpeng; Wang, S. [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang Bin, E-mail: ymwang@ustc.edu.cn, E-mail: ymwang@ustc.edu.cn [Beijing Institute of Tracking and Telecommunication Technology, Beijing 100094 (China)

    2012-10-20

    Waves play a crucial role in diagnosing the plasma properties of various structures in the solar corona and coronal heating. Slow magnetoacoustic (MA) waves are one of the important types of magnetohydrodynamic waves. In past decades, numerous slow MA waves were detected above active regions and coronal holes, but were rarely found elsewhere. Here, we investigate a 'tornado'-like structure consisting of quasi-periodic streaks within a dark cavity at about 40-110 Mm above a quiet-Sun region on 2011 September 25. Our analysis reveals that these streaks are actually slow MA wave trains. The properties of these wave trains, including phase speed, compression ratio, and kinetic energy density, are similar to those of the reported slow MA waves, except that the period of these waves is about 50 s, much shorter than the typical reported values (3-5 minutes).

  18. Overnight changes in the slope of sleep slow waves during infancy.

    Science.gov (United States)

    Fattinger, Sara; Jenni, Oskar G; Schmitt, Bernhard; Achermann, Peter; Huber, Reto

    2014-02-01

    Slow wave activity (SWA, 0.5-4.5 Hz) is a well-established marker for sleep pressure in adults. Recent studies have shown that increasing sleep pressure is reflected by an increased synchronized firing pattern of cortical neurons, which can be measured by the slope of sleep slow waves. Thus we aimed at investigating whether the slope of sleep slow waves might provide an alternative marker to study the homeostatic regulation of sleep during early human development. All-night sleep electroencephalography (EEG) was recorded longitudinally at 2, 4, 6, and 9 months after birth. Home recording. 11 healthy full-term infants (5 male, 6 female). None. The slope of sleep slow waves increased with age. At all ages the slope decreased from the first to the last hour of non rapid-eye-movement (NREM) sleep, even when controlling for amplitude differences (P why the steepest slope was found in the occipital derivation. Our results provide evidence that the homeostatic regulation of sleep develops early in human infants.

  19. Generation of microwaves by a slow wave electron cyclotron maser with axial injection

    International Nuclear Information System (INIS)

    Michie, R.B.; Vomvoridis, J.

    1984-01-01

    Experimental measurements of microwave generation by a new electron beam wave interaction is presented. This slow wave electron cyclotron maser (ECM) has a continuous electron beam injected axially into a slow wave structure containing a circularly polarized HE, hybrid electric (HE) mode. A longitudinal magnetic field produces microwaves by maser action. The slow wave structure allows energy to be coupled out of an electron beam with no initial transverse momentum. This is similar to klystrons, traveling wave tubes, and Cherenkov masers, but there is no axial beam bunching. Therefore, ECM designs using relativistic electron beams are allowed. This ECM is similar to a gyrotron in that the electrons are coupled through their cyclotron motion to the wave, but there is no need for initial electron velocity perpendicular to the background magnetic field. Therefore, a narrower spread of electron beam energy about the ECM resonance is possible which gives higher theoretical efficiency. A nonlinear analysis of energy coupling of electrons to the slow wave in the ECM and the design of the slow wave ECM microwave amplifier at 10 GHz using a 200 KeV axial electron beam in 3 KG magnetic field is included

  20. Penetration of slow waves into an overdense plasma

    International Nuclear Information System (INIS)

    Motley, R.W.; Bernabei, S.; Hooke, W.M.; McWilliams, R.; Olson, L.

    1978-06-01

    Probe measurements are reported of the propagation of a 2.45 GHz slow wave launched into a linear, overdense test plasma by a phased double waveguide. We find that waves in the frequency interval omega/sub LH/ < omega < omega/sub pe/ penetrate to the plasma interior only if they satisfy the accessibility criterion

  1. Reconstruction of gastric slow wave from finger photoplethysmographic signal using radial basis function neural network.

    Science.gov (United States)

    Mohamed Yacin, S; Srinivasa Chakravarthy, V; Manivannan, M

    2011-11-01

    Extraction of extra-cardiac information from photoplethysmography (PPG) signal is a challenging research problem with significant clinical applications. In this study, radial basis function neural network (RBFNN) is used to reconstruct the gastric myoelectric activity (GMA) slow wave from finger PPG signal. Finger PPG and GMA (measured using Electrogastrogram, EGG) signals were acquired simultaneously at the sampling rate of 100 Hz from ten healthy subjects. Discrete wavelet transform (DWT) was used to extract slow wave (0-0.1953 Hz) component from the finger PPG signal; this slow wave PPG was used to reconstruct EGG. A RBFNN is trained on signals obtained from six subjects in both fasting and postprandial conditions. The trained network is tested on data obtained from the remaining four subjects. In the earlier study, we have shown the presence of GMA information in finger PPG signal using DWT and cross-correlation method. In this study, we explicitly reconstruct gastric slow wave from finger PPG signal by the proposed RBFNN-based method. It was found that the network-reconstructed slow wave provided significantly higher (P wave than the correlation obtained (≈0.7) between the PPG slow wave from DWT and the EEG slow wave. Our results showed that a simple finger PPG signal can be used to reconstruct gastric slow wave using RBFNN method.

  2. Slow wave activity and slow oscillations in sleepwalkers and controls: effects of 38 h of sleep deprivation.

    Science.gov (United States)

    Perrault, Rosemarie; Carrier, Julie; Desautels, Alex; Montplaisir, Jacques; Zadra, Antonio

    2013-08-01

    Sleepwalkers have been shown to have an unusually high number of arousals from slow wave sleep and lower slow wave activity (SWA) power during the night than controls. Because sleep deprivation increases the frequency of slow wave sleep (SWS) arousals in sleepwalkers, it may also affect the expression of the homeostatic process to a greater extent than shown previously. We thus investigated SWA power as well as slow wave oscillation (SWO) density in 10 sleepwalkers and nine controls at baseline and following 38 h of sleep deprivation. There was a significant increase in SWA during participants' recovery sleep, especially during their second non-rapid eye movement (NREM) period. SWO density was similarly increased during recovery sleep's first two NREM periods. A fronto-central gradient in SWA and SWO was also present on both nights. However, no group differences were noted on any of the 2 nights on SWA or SWO. This unexpected result may be related to the heterogeneity of sleepwalkers as a population, as well as our small sample size. SWA pressure after extended sleep deprivation may also result in a ceiling effect in both sleepwalkers and controls. © 2013 European Sleep Research Society.

  3. Vagus Nerve Stimulation for Electrographic Status Epilepticus in Slow-Wave Sleep.

    Science.gov (United States)

    Carosella, Christopher M; Greiner, Hansel M; Byars, Anna W; Arthur, Todd M; Leach, James L; Turner, Michele; Holland, Katherine D; Mangano, Francesco T; Arya, Ravindra

    2016-07-01

    Electrographic status epilepticus in slow sleep or continuous spike and waves during slow-wave sleep is an epileptic encephalopathy characterized by seizures, neurocognitive regression, and significant activation of epileptiform discharges during nonrapid eye movement sleep. There is no consensus on the diagnostic criteria and evidence-based optimal treatment algorithm for children with electrographic status epilepticus in slow sleep. We describe a 12-year-old girl with drug-resistant electrographic status epilepticus in slow wave sleep that was successfully treated with vagus nerve stimulation. Her clinical presentation, presurgical evaluation, decision-making, and course after vagus nerve stimulator implantation are described in detail. After vagus nerve stimulator implantation, the girl remained seizure free for more than a year, resolved the electrographic status epilepticus in slow sleep pattern on electroencephalography, and exhibited significant cognitive improvement. Vagus nerve stimulation may be considered for electrographic status epilepticus in slow sleep. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Ponderomotive force effects on slow-wave coupling

    International Nuclear Information System (INIS)

    Wilson, J.R.; Wong, K.L.

    1982-01-01

    Localized plasma density depressions are observed to form near a multi-ring slow-wave structure when the value of the nonlinearity parameter, s = ω 2 /sub p/eVertical BarE/sub z/Vertical Bar 2 /8πω 2 nkappaT, is of order unity. Consequent changes in the wave propagation and coupling efficiency are reported. For large enough values of s, the coupling efficiency may be reduced by 50% from the linear value

  5. Shorter duration of non-rapid eye movement sleep slow waves in EphA4 knockout mice.

    Science.gov (United States)

    Freyburger, Marlène; Poirier, Gaétan; Carrier, Julie; Mongrain, Valérie

    2017-10-01

    Slow waves occurring during non-rapid eye movement sleep have been associated with neurobehavioural performance and memory. In addition, the duration of previous wakefulness and sleep impacts characteristics of these slow waves. However, molecular mechanisms regulating the dynamics of slow-wave characteristics remain poorly understood. The EphA4 receptor regulates glutamatergic transmission and synaptic plasticity, which have both been linked to sleep slow waves. To investigate if EphA4 regulates slow-wave characteristics during non-rapid eye movement sleep, we compared individual parameters of slow waves between EphA4 knockout mice and wild-type littermates under baseline conditions and after a 6-h sleep deprivation. We observed that, compared with wild-type mice, knockout mice display a shorter duration of positive and negative phases of slow waves under baseline conditions and after sleep deprivation. However, the mutation did not change slow-wave density, amplitude and slope, and did not affect the sleep deprivation-dependent changes in slow-wave characteristics, suggesting that EphA4 is not involved in the response to elevated sleep pressure. Our present findings suggest a role for EphA4 in shaping cortical oscillations during sleep that is independent from sleep need. © 2017 European Sleep Research Society.

  6. Effect of Local Thermal Equilibrium Misbalance on Long-wavelength Slow Magnetoacoustic Waves

    Energy Technology Data Exchange (ETDEWEB)

    Nakariakov, V. M. [Centre for Fusion, Space and Astrophysics, Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Afanasyev, A. N. [Institute of Solar-Terrestrial Physics SB RAS, P.O. Box 291, Lermontov St. 126A, Irkutsk 664033 (Russian Federation); Kumar, S.; Moon, Y.-J., E-mail: V.Nakariakov@warwick.ac.uk [School of Space Research, Kyung Hee University, Yongin, 446-701, Gyeonggi (Korea, Republic of)

    2017-11-01

    Evolution of slow magnetoacoustic waves guided by a cylindrical magnetic flux tube that represents a coronal loop or plume, is modeled accounting for the effects of finite gas pressure, weak nonlinearity, dissipation by thermal conduction and viscosity, and the misbalance between the cooling by optically thin radiation and unspecified heating of the plasma. An evolutionary equation of the Burgers–Malthus type is derived. It is shown that the cooling/heating misbalance, determined by the derivatives of the combined radiative cooling and heating function, with respect to the density, temperature, and magnetic field at the thermal equilibrium affect the wave rather strongly. This effect may either cause additional damping, or counteract it, or lead to the gradual amplification of the wave. In the latter case, the coronal plasma acts as an active medium for the slow magnetoacoustic waves. The effect of the cooling/heating misbalance could be important for coronal slow waves, and could be responsible for certain discrepancies between theoretical results and observations, in particular, the increased or decreased damping lengths and times, detection of the waves at certain heights only, and excitation of compressive oscillations. The results obtained open up a possibility for the diagnostics of the coronal heating function by slow magnetoacoustic waves.

  7. The Roles of Cortical Slow Waves in Synaptic Plasticity and Memory Consolidation

    OpenAIRE

    Miyamoto, Daisuke; Hirai, Daichi; Murayama, Masanori

    2017-01-01

    Sleep plays important roles in sensory and motor memory consolidation. Sleep oscillations, reflecting neural population activity, involve the reactivation of learning-related neurons and regulate synaptic strength and, thereby affect memory consolidation. Among sleep oscillations, slow waves (0.5–4 Hz) are closely associated with memory consolidation. For example, slow-wave power is regulated in an experience-dependent manner and correlates with acquired memory. Furthermore, manipulating slow...

  8. The Roles of Cortical Slow Waves in Synaptic Plasticity and Memory Consolidation.

    Science.gov (United States)

    Miyamoto, Daisuke; Hirai, Daichi; Murayama, Masanori

    2017-01-01

    Sleep plays important roles in sensory and motor memory consolidation. Sleep oscillations, reflecting neural population activity, involve the reactivation of learning-related neurons and regulate synaptic strength and, thereby affect memory consolidation. Among sleep oscillations, slow waves (0.5-4 Hz) are closely associated with memory consolidation. For example, slow-wave power is regulated in an experience-dependent manner and correlates with acquired memory. Furthermore, manipulating slow waves can enhance or impair memory consolidation. During slow wave sleep, inter-areal interactions between the cortex and hippocampus (HC) have been proposed to consolidate declarative memory; however, interactions for non-declarative (HC-independent) memory remain largely uninvestigated. We recently showed that the directional influence in a slow-wave range through a top-down cortical long-range circuit is involved in the consolidation of non-declarative memory. At the synaptic level, the average cortical synaptic strength is known to be potentiated during wakefulness and depressed during sleep. Moreover, learning causes plasticity in a subset of synapses, allocating memory to them. Sleep may help to differentiate synaptic strength between allocated and non-allocated synapses (i.e., improving the signal-to-noise ratio, which may facilitate memory consolidation). Herein, we offer perspectives on inter-areal interactions and synaptic plasticity for memory consolidation during sleep.

  9. The Roles of Cortical Slow Waves in Synaptic Plasticity and Memory Consolidation

    Directory of Open Access Journals (Sweden)

    Daisuke Miyamoto

    2017-11-01

    Full Text Available Sleep plays important roles in sensory and motor memory consolidation. Sleep oscillations, reflecting neural population activity, involve the reactivation of learning-related neurons and regulate synaptic strength and, thereby affect memory consolidation. Among sleep oscillations, slow waves (0.5–4 Hz are closely associated with memory consolidation. For example, slow-wave power is regulated in an experience-dependent manner and correlates with acquired memory. Furthermore, manipulating slow waves can enhance or impair memory consolidation. During slow wave sleep, inter-areal interactions between the cortex and hippocampus (HC have been proposed to consolidate declarative memory; however, interactions for non-declarative (HC-independent memory remain largely uninvestigated. We recently showed that the directional influence in a slow-wave range through a top-down cortical long-range circuit is involved in the consolidation of non-declarative memory. At the synaptic level, the average cortical synaptic strength is known to be potentiated during wakefulness and depressed during sleep. Moreover, learning causes plasticity in a subset of synapses, allocating memory to them. Sleep may help to differentiate synaptic strength between allocated and non-allocated synapses (i.e., improving the signal-to-noise ratio, which may facilitate memory consolidation. Herein, we offer perspectives on inter-areal interactions and synaptic plasticity for memory consolidation during sleep.

  10. Identification of slow magnetosonic wave trains and their evolution in 3-D compressible turbulence simulation

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2015-01-01

    Full Text Available In solar wind, dissipation of slow-mode magnetosonic waves may play a significant role in heating the solar wind, and these modes contribute essentially to the solar wind compressible turbulence. Most previous identifications of slow waves utilized the characteristic negative correlation between δ|B| and δρ. However, that criterion does not well identify quasi-parallel slow waves, for which δ|B| is negligible compared to δρ. Here we present a new method of identification, which will be used in 3-D compressible simulation. It is based on two criteria: (1 that VpB0 (phase speed projected along B0 is around ± cs, and that (2 there exists a clear correlation of δv|| and δρ. Our research demonstrates that if vA > cs, slow waves possess correlation between δv|| and δρ, with δρ / δv|| ≈ ± ρ0 / cs. This method helps us to distinguish slow-mode waves from fast and Alfvén waves, both of which do not have this polarity relation. The criteria are insensitive to the propagation angle θk B, defined as the angle between wave vector k and B0; they can be applied with a wide range of β if only vA > cs. In our numerical simulation, we have identified four cases of slow wave trains with this method. The slow wave trains seem to deform, probably caused by interaction with other waves; as a result, fast or Alfvén waves may be produced during the interaction and seem to propagate bidirectionally away. Our identification and analysis of the wave trains provide useful methods for investigations of compressible turbulence in the solar wind or in similar environments, and will thus deepen understandings of slow waves in the turbulence.

  11. EEG slow-wave coherence changes in propofol-induced general anesthesia: Experiment and theory

    Directory of Open Access Journals (Sweden)

    Kaier eWang

    2014-10-01

    Full Text Available The electroencephalogram (EEG patterns recorded during general anesthetic-induced coma are closely similar to those seen during slow-wave sleep, the deepest stage of natural sleep; both states show patterns dominated by large amplitude slow waves. Slow oscillations are believed to be important for memory consolidation during natural sleep. Tracking the emergence of slow-wave oscillations during transition to unconsciousness may help us to identify drug-induced alterations of the underlying brain state, and provide insight into the mechanisms of general anesthesia. Although cellular-based mechanisms have been proposed, the origin of the slow oscillation has not yet been unambiguously established. A recent theoretical study by Steyn-Ross et al. [Physical Review X 3(2, 021005 (2013] proposes that the slow oscillation is a network, rather than cellular phenomenon. Modeling anesthesia as a moderate reduction in gap-junction interneuronal coupling, they predict an unconscious state signposted by emergent low-frequency oscillations with chaotic dynamics in space and time. They suggest that anesthetic slow-waves arise from a competitive interaction between symmetry-breaking instabilities in space (Turing and time (Hopf, modulated by gap-junction coupling strength. A significant prediction of their model is that EEG phase coherence will decrease as the cortex transits from Turing--Hopf balance (wake to Hopf-dominated chaotic slow-waves (unconsciousness. Here, we investigate changes in phase coherence during induction of general anesthesia. After examining 128-channel EEG traces recorded from five volunteers undergoing propofol anesthesia, we report a significant drop in sub-delta band (0.05--1.5 Hz slow-wave coherence between frontal, occipital, and frontal-occipital electrode pairs, with the most pronounced wake-versus-unconscious coherence changes occurring at the frontal cortex.

  12. Investigation of Slow-wave Activity Saturation during Surgical Anesthesia Reveals a Signature of Neural Inertia in Humans.

    Science.gov (United States)

    Warnaby, Catherine E; Sleigh, Jamie W; Hight, Darren; Jbabdi, Saad; Tracey, Irene

    2017-10-01

    Previously, we showed experimentally that saturation of slow-wave activity provides a potentially individualized neurophysiologic endpoint for perception loss during anesthesia. Furthermore, it is clear that induction and emergence from anesthesia are not symmetrically reversible processes. The observed hysteresis is potentially underpinned by a neural inertia mechanism as proposed in animal studies. In an advanced secondary analysis of 393 individual electroencephalographic data sets, we used slow-wave activity dose-response relationships to parameterize slow-wave activity saturation during induction and emergence from surgical anesthesia. We determined whether neural inertia exists in humans by comparing slow-wave activity dose responses on induction and emergence. Slow-wave activity saturation occurs for different anesthetics and when opioids and muscle relaxants are used during surgery. There was wide interpatient variability in the hypnotic concentrations required to achieve slow-wave activity saturation. Age negatively correlated with power at slow-wave activity saturation. On emergence, we observed abrupt decreases in slow-wave activity dose responses coincident with recovery of behavioral responsiveness in ~33% individuals. These patients are more likely to have lower power at slow-wave activity saturation, be older, and suffer from short-term confusion on emergence. Slow-wave activity saturation during surgical anesthesia implies that large variability in dosing is required to achieve a targeted potential loss of perception in individual patients. A signature for neural inertia in humans is the maintenance of slow-wave activity even in the presence of very-low hypnotic concentrations during emergence from anesthesia.

  13. Slow wave antenna coupling to ion Bernstein waves for plasma heating in ICRF

    International Nuclear Information System (INIS)

    Sy, W.N-C.; Amano, T.; Ando, R.; Fukuyama, A.; Watari, T.

    1984-10-01

    The coupling of ICRF power from a slow wave antenna to a plasma with finite temperature is examined theoretically and compared to an independent computer calculation. It is shown that such antennas can be highly efficient in trasferring most of the antenna power directly to ion Bernstein waves, with only a very small fraction going into fast waves. The potentiality of this coupling scheme for plasma heating in ICRF is briefly discussed. (author)

  14. Enhanced traveling wave amplification of co-planar slow wave structure by extended phase-matching

    International Nuclear Information System (INIS)

    Palm, Andrew; Sirigiri, Jagadishwar; Shin, Young-Min

    2015-01-01

    The electron beam co-propagating with slow waves in a staggered double grating array (SDGA) efficiently amplifies millimeter and sub-millimeter waves over a wide spectrum. Our theoretical and numerical analyses show that the power amplification in the fundamental passband is enhanced by the extended beam-wave phase-matching. Particle-in-cell simulations on the SDGA slow wave structure, designed with 10.4 keV and 50–100 mA sheet beam, indicate that maintaining beam-wave synchronization along the entire length of the circuit improves the gain by 7.3% leading to a total gain of 28 dB, corresponding to 62 W saturated power at the middle of operating band, and a 3-dB bandwidth of 7 GHz with 10.5% at V-band (73.5 GHz center frequency) with saturated peak power reaching 80 W and 28 dB at 71 GHz. These results also show a reasonably good agreement with analytic calculations based on Pierce small signal gain theory

  15. Influence Coefficients of Constructive Parameters of Meander Slow-Wave System with Additional Shields

    Directory of Open Access Journals (Sweden)

    Metlevskis Edvardas

    2016-12-01

    Full Text Available Constructions of meander slow-wave systems with additional shields grounded at different positions are presented. The construction of meander slow-wave systems with additional shields grounded at both edges is investigated in detail. The influence of the main constructive parameters on the electrical characteristics of meander slow-wave systems with additional shields grounded at both edges is evaluated. The main constructive parameters of the investigated system are: the length of the conductor, the width of meander conductor, the width of additional shield, and the width of the gap between adjacent meander conductors.

  16. Dynamic analysis of the conditional oscillator underlying slow waves in thalamocortical neurons

    Directory of Open Access Journals (Sweden)

    Francois eDavid

    2016-02-01

    Full Text Available During non-REM sleep the EEG shows characteristics waves that are generated by the dynamic interactions between cortical and thalamic oscillators. In thalamic neurons, low-threshold T-type Ca2+ channels play a pivotal role in almost every type of neuronal oscillations, including slow (<1 Hz waves, sleep spindles and delta waves. The transient opening of T channels gives rise to the low threshold spikes (LTSs, and associated high frequency bursts of action potentials, that are characteristically present during sleep spindles and delta waves, whereas the persistent opening of a small fraction of T channels, (i.e. ITwindow is responsible for the membrane potential bistability underlying sleep slow oscillations. Surprisingly thalamocortical (TC neurons express a very high density of T channels that largely exceed the amount required to generate LTSs and therefore, to support certain, if not all, sleep oscillations. Here, to clarify the relationship between T current density and sleep oscillations, we systematically investigated the impact of the T conductance level on the intrinsic rhythmic activities generated in TC neurons, combining in vitro experiments and TC neuron simulation. Using bifurcation analysis, we provide insights into the dynamical processes taking place at the transition between slow and delta oscillations. Our results show that although stable delta oscillations can be evoked with minimal T conductance, the full range of slow oscillation patterns, including groups of delta oscillations separated by Up states (grouped-delta slow waves requires a high density of T channels. Moreover, high levels of T conductance ensure the robustness of different types of slow oscillations.

  17. Improved Visualization of Gastrointestinal Slow Wave Propagation Using a Novel Wavefront-Orientation Interpolation Technique.

    Science.gov (United States)

    Mayne, Terence P; Paskaranandavadivel, Niranchan; Erickson, Jonathan C; OGrady, Gregory; Cheng, Leo K; Angeli, Timothy R

    2018-02-01

    High-resolution mapping of gastrointestinal (GI) slow waves is a valuable technique for research and clinical applications. Interpretation of high-resolution GI mapping data relies on animations of slow wave propagation, but current methods remain as rudimentary, pixelated electrode activation animations. This study aimed to develop improved methods of visualizing high-resolution slow wave recordings that increases ease of interpretation. The novel method of "wavefront-orientation" interpolation was created to account for the planar movement of the slow wave wavefront, negate any need for distance calculations, remain robust in atypical wavefronts (i.e., dysrhythmias), and produce an appropriate interpolation boundary. The wavefront-orientation method determines the orthogonal wavefront direction and calculates interpolated values as the mean slow wave activation-time (AT) of the pair of linearly adjacent electrodes along that direction. Stairstep upsampling increased smoothness and clarity. Animation accuracy of 17 human high-resolution slow wave recordings (64-256 electrodes) was verified by visual comparison to the prior method showing a clear improvement in wave smoothness that enabled more accurate interpretation of propagation, as confirmed by an assessment of clinical applicability performed by eight GI clinicians. Quantitatively, the new method produced accurate interpolation values compared to experimental data (mean difference 0.02 ± 0.05 s) and was accurate when applied solely to dysrhythmic data (0.02 ± 0.06 s), both within the error in manual AT marking (mean 0.2 s). Mean interpolation processing time was 6.0 s per wave. These novel methods provide a validated visualization platform that will improve analysis of high-resolution GI mapping in research and clinical translation.

  18. Different Effects of Sleep Deprivation and Torpor on EEG Slow-Wave Characteristics in Djungarian Hamsters.

    Science.gov (United States)

    Vyazovskiy, V V; Palchykova, S; Achermann, P; Tobler, I; Deboer, T

    2017-02-01

    It has been shown previously in Djungarian hamsters that the initial electroencephalography (EEG) slow-wave activity (power in the 0.5-4.0 Hz band; SWA) in non-rapid eye movement (NREM) sleep following an episode of daily torpor is consistently enhanced, similar to the SWA increase after sleep deprivation (SD). However, it is unknown whether the network mechanisms underlying the SWA increase after torpor and SD are similar. EEG slow waves recorded in the neocortex during sleep reflect synchronized transitions between periods of activity and silence among large neuronal populations. We therefore set out to investigate characteristics of individual cortical EEG slow waves recorded during NREM sleep after 4 h SD and during sleep after emergence from an episode of daily torpor in adult male Djungarian hamsters. We found that during the first hour after both SD and torpor, the SWA increase was associated with an increase in slow-wave incidence and amplitude. However, the slopes of single slow waves during NREM sleep were steeper in the first hour after SD but not after torpor, and, in contrast to sleep after SD, the magnitude of change in slopes after torpor was unrelated to the changes in SWA. Furthermore, slow-wave slopes decreased progressively within the first 2 h after SD, while a progressive increase in slow-wave slopes was apparent during the first 2 h after torpor. The data suggest that prolonged waking and torpor have different effects on cortical network activity underlying slow-wave characteristics, while resulting in a similar homeostatic sleep response of SWA. We suggest that sleep plays an important role in network homeostasis after both waking and torpor, consistent with a recovery function for both states. © The Author 2017. Published by Oxford University Press.

  19. Is there a relation between EEG-slow waves and memory dysfunction in epilepsy? A critical appraisal.

    Directory of Open Access Journals (Sweden)

    Höller eYvonne

    2015-06-01

    Full Text Available Is there a relationship between peri-ictal slow waves, loss of consciousness, memory, and slow wave sleep, in patients with different forms of epilepsy? We hypothesize that mechanisms which result in peri-ictal slow wave activity as detected by the electroencephalogram could negatively affect memory processes.Slow waves (≤ 4 Hz can be found in seizures with impairment of consciousness and also occur in focal seizures without impairment of consciousness but with inhibited access to memory functions. Peri-ictal slow waves are regarded as dysfunctional and are probably caused by mechanisms which are essential to disturb the consolidation of memory entries in these patients. This is in strong contrast to physiological slow wave activity during deep sleep, which is thought to group memory-consolidating fast oscillatory activity.In patients with epilepsy, slow waves may not only correlate with the peri-ictal clouding of consciousness, but could be the epiphenomenon of mechanisms which interfere with normal brain function in a wider range. These mechanisms may have transient impacts on memory, such as temporary inhibition of memory systems, altered patterns of hippocampal-neocortical interactions during slow wave sleep, or disturbed cross-frequency coupling of slow and fast oscillations. In addition, repeated tonic-clonic seizures over the years in uncontrolled chronic epilepsy may cause a progressive cognitive decline.This hypothesis can only be assessed in long term prospective studies. These studies could disentangle the reversible short-term impacts of seizures, and the impacts of chronic uncontrolled seizures. Chronic uncontrolled seizures lead to irreversible memory impairment. In contrast, short term impacts do not necessarily lead to a progressive cognitive decline but result in significantly impaired peri-ictal memory performance.

  20. MODELING OF REFLECTIVE PROPAGATING SLOW-MODE WAVE IN A FLARING LOOP

    Energy Technology Data Exchange (ETDEWEB)

    Fang, X.; Yuan, D.; Van Doorsselaere, T.; Keppens, R.; Xia, C. [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, B-3001 Leuven (Belgium)

    2015-11-01

    Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in extreme ultraviolet images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed their association with persistent coronal upflows, making this interpretation debatable. We perform a 2.5D magnetohydrodynamic simulation to imitate the chromospheric evaporation and the following reflected patterns in a flare loop. Our model encompasses the corona, transition region, and chromosphere. We demonstrate that the quasi periodic propagating intensity variations captured by the synthesized Solar Dynamics Observatory/Atmospheric Imaging Assembly 131, 94 Å emission images match the previous observations well. With particle tracers in the simulation, we confirm that these quasi periodic propagating intensity variations consist of reflected slow mode waves and mass flows with an average speed of 310 km s{sup −1} in an 80 Mm length loop with an average temperature of 9 MK. With the synthesized Doppler shift velocity and intensity maps of the Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation Fe xix line emission, we confirm that these reflected slow mode waves are propagating waves.

  1. Effects of body mass index on gastric slow wave: a magnetogastrographic study

    International Nuclear Information System (INIS)

    Somarajan, S; Cassilly, S; Obioha, C; Bradshaw, L A; Richards, W O

    2014-01-01

    We measured gastric slow wave activity simultaneously with magnetogastrogram (MGG), mucosal electromyogram (EMG) and electrogastrogram (EGG) in human subjects with varying body mass index (BMI) before and after a meal. In order to investigate the effect of BMI on gastric slow wave parameters, each subject's BMI was calculated and divided into two groups: subjects with BMI ≤ 27 and BMI > 27. Signals were processed with Fourier spectral analysis and second-order blind identification (SOBI) techniques. Our results showed that increased BMI does not affect signal characteristics such as frequency and amplitude of EMG and MGG. Comparison of the postprandial EGG power, on the other hand, showed a statistically significant reduction in subjects with BMI > 27 compared with BMI ≤ 27. In addition to the frequency and amplitude, the use of SOBI-computed propagation maps from MGG data allowed us to visualize the propagating slow wave and compute the propagation velocity in both BMI groups. No significant change in velocity with increasing BMI or meal was observed in our study. In conclusion, multichannel MGG provides an assessment of frequency, amplitude and propagation velocity of the slow wave in subjects with differing BMI categories and was observed to be independent of BMI. (paper)

  2. Acoustic slow waves and the consolidation transition

    International Nuclear Information System (INIS)

    Johnson, D.L.; Plona, T.J.

    1982-01-01

    We have investigated the ultrasonic properties of unconsolidated (loose) glass beads and of lightly fused (consolidated) glass beads when the pore space is saturated with water. At a frequency of 500 kHz we have observed a single compressional wave in the former whose speed is 1.79 km/s and two distinct compressional waves with speeds 2.81 km/s and 0.96 km/s in the latter. The Biot theory is shown to give an accurate description of this phenomenon. We also analyze the acoustics of low temperature He ii in packed powder superleaks; either the fast wave for unconsolidated systems or the slow wave in a highly consolidated (fused) frame may be considered to be the 4th sound mode. In all such systems, the acoustic properties can be very simply understood by considering the velocities of propagation as continuous functions of the elastic moduli of the solid skeletal frames

  3. Slow waves in microchannel metal waveguides and application to particle acceleration

    Directory of Open Access Journals (Sweden)

    L. C. Steinhauer

    2003-06-01

    Full Text Available Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO_{2} lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ∼0.6  mm. The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

  4. Slow waves in microchannel metal waveguides and application to particle acceleration

    Science.gov (United States)

    Steinhauer, L. C.; Kimura, W. D.

    2003-06-01

    Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO2 lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ˜0.6 mm). The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

  5. Resting-state slow wave power, healthy aging and cognitive performance.

    Science.gov (United States)

    Vlahou, Eleni L; Thurm, Franka; Kolassa, Iris-Tatjana; Schlee, Winfried

    2014-05-29

    Cognitive functions and spontaneous neural activity show significant changes over the life-span, but the interrelations between age, cognition and resting-state brain oscillations are not well understood. Here, we assessed performance on the Trail Making Test and resting-state magnetoencephalographic (MEG) recordings from 53 healthy adults (18-89 years old) to investigate associations between age-dependent changes in spontaneous oscillatory activity and cognitive performance. Results show that healthy aging is accompanied by a marked and linear decrease of resting-state activity in the slow frequency range (0.5-6.5 Hz). The effects of slow wave power on cognitive performance were expressed as interactions with age: For older (>54 years), but not younger participants, enhanced delta and theta power in temporal and central regions was positively associated with perceptual speed and executive functioning. Consistent with previous work, these findings substantiate further the important role of slow wave oscillations in neurocognitive function during healthy aging.

  6. Slow cyclotron waves in a waveguide with a relativistic electron beam

    International Nuclear Information System (INIS)

    Korenev, I.L.; Yudin, L.A.; Mustafin, Kh.Kh.

    1979-01-01

    Using the analytical methods the problem about propagation of waves of a small amplitude in an electron beam (without ions), moving along the axis of a smooth waveguide in the longitudinal magnetic field is considered. The main attention is paid to dispersion.characteristics and the slow cyclotron waves intended for ion acceleration. The problems connected with utilization of these waves for ion acceleration are discussed. The estimation shows that when a system of excitation of an accelerating wave has a wide range, i.e. excited is a great set of slow cyclotron modes, the accelerating field structure significantly changes at a distance of several dozens beam radii, and synchronism supply between the wave and accelerating ions becomes an impracticable task. So it is necessary to have a narrow-band excitation system to excite only a single mode. It is noted that the model used of a uniform beam density along the cross section is an idealization permitting to simplify analytical consideration. The presence of the radial density change in an undisturbed beam will lead to some other cyclotron wave field structure. However, such a change will not give any qualitative differences in comparison with the results obtained

  7. Simultaneous realization of slow and fast acoustic waves using a fractal structure of Koch curve.

    Science.gov (United States)

    Ding, Jin; Fan, Li; Zhang, Shu-Yi; Zhang, Hui; Yu, Wei-Wei

    2018-01-24

    An acoustic metamaterial based on a fractal structure, the Koch curve, is designed to simultaneously realize slow and fast acoustic waves. Owing to the multiple transmitting paths in the structure resembling the Koch curve, the acoustic waves travelling along different paths interfere with each other. Therefore, slow waves are created on the basis of the resonance of a Koch-curve-shaped loop, and meanwhile, fast waves even with negative group velocities are obtained due to the destructive interference of two acoustic waves with opposite phases. Thus, the transmission of acoustic wave can be freely manipulated with the Koch-curve shaped structure.

  8. Enhanced four-wave mixing in graphene-silicon slow-light photonic crystal waveguides

    International Nuclear Information System (INIS)

    Zhou, Hao; Gu, Tingyi; McMillan, James F.; Wong, Chee Wei; Petrone, Nicholas; Zande, Arend van der; Hone, James C.; Yu, Mingbin; Lo, Guoqiang; Kwong, Dim-Lee; Feng, Guoying; Zhou, Shouhuan

    2014-01-01

    We demonstrate the enhanced four-wave mixing of monolayer graphene on slow-light silicon photonic crystal waveguides. 200-μm interaction length, a four-wave mixing conversion efficiency of −23 dB is achieved in the graphene-silicon slow-light hybrid, with an enhanced 3-dB conversion bandwidth of about 17 nm. Our measurements match well with nonlinear coupled-mode theory simulations based on the measured waveguide dispersion, and provide an effective way for all-optical signal processing in chip-scale integrated optics.

  9. Excitatory Neuronal Hubs Configure Multisensory Integration of Slow Waves in Association Cortex

    Directory of Open Access Journals (Sweden)

    Satoshi Kuroki

    2018-03-01

    Full Text Available Summary: Multisensory integration (MSI is a fundamental emergent property of the mammalian brain. During MSI, perceptual information encoded in patterned activity is processed in multimodal association cortex. The systems-level neuronal dynamics that coordinate MSI, however, are unknown. Here, we demonstrate intrinsic hub-like network activity in the association cortex that regulates MSI. We engineered calcium reporter mouse lines based on the fluorescence resonance energy transfer sensor yellow cameleon (YC2.60 expressed in excitatory or inhibitory neurons. In medial and parietal association cortex, we observed spontaneous slow waves that self-organized into hubs defined by long-range excitatory and local inhibitory circuits. Unlike directional source/sink-like flows in sensory areas, medial/parietal excitatory and inhibitory hubs had net-zero balanced inputs. Remarkably, multisensory stimulation triggered rapid phase-locking mainly of excitatory hub activity persisting for seconds after the stimulus offset. Therefore, association cortex tends to form balanced excitatory networks that configure slow-wave phase-locking for MSI. Video Abstract: : Kuroki et al. performed cell-type-specific, wide-field FRET-based calcium imaging to visualize cortical network activity induced by multisensory inputs. They observed phase-locking of cortical slow waves in excitatory neuronal hubs in association cortical areas that may underlie multisensory integration. Keywords: wide-field calcium imaging, multisensory integration, cortical slow waves, association cortex, phase locking, fluorescence resonance energy transfer, spontaneous activity, excitatory neuron, inhibitory neuron, mouse

  10. Giant amplification in degenerate band edge slow-wave structures interacting with an electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Mohamed A. K.; Veysi, Mehdi; Capolino, Filippo [Department of Electrical Engineering and Computer Science, University of California, Irvine, California 92697 (United States); Figotin, Alexander [Department of Mathematics, University of California, Irvine, California 92697 (United States)

    2016-03-15

    We propose a new amplification regime based on a synchronous operation of four degenerate electromagnetic (EM) modes in a slow-wave structure and the electron beam, referred to as super synchronization. These four EM modes arise in a Fabry-Pérot cavity when degenerate band edge (DBE) condition is satisfied. The modes interact constructively with the electron beam resulting in superior amplification. In particular, much larger gains are achieved for smaller beam currents compared to conventional structures based on synchronization with only a single EM mode. We demonstrate giant gain scaling with respect to the length of the slow-wave structure compared to conventional Pierce type single mode traveling wave tube amplifiers. We construct a coupled transmission line model for a loaded waveguide slow-wave structure exhibiting a DBE, and investigate the phenomenon of giant gain via super synchronization using the Pierce model generalized to multimode interaction.

  11. Effects of partial sleep deprivation on slow waves during non-rapid eye movement sleep: A high density EEG investigation.

    Science.gov (United States)

    Plante, David T; Goldstein, Michael R; Cook, Jesse D; Smith, Richard; Riedner, Brady A; Rumble, Meredith E; Jelenchick, Lauren; Roth, Andrea; Tononi, Giulio; Benca, Ruth M; Peterson, Michael J

    2016-02-01

    Changes in slow waves during non-rapid eye movement (NREM) sleep in response to acute total sleep deprivation are well-established measures of sleep homeostasis. This investigation utilized high-density electroencephalography (hdEEG) to examine topographic changes in slow waves during repeated partial sleep deprivation. Twenty-four participants underwent a 6-day sleep restriction protocol. Spectral and period-amplitude analyses of sleep hdEEG data were used to examine changes in slow wave energy, count, amplitude, and slope relative to baseline. Changes in slow wave energy were dependent on the quantity of NREM sleep utilized for analysis, with widespread increases during sleep restriction and recovery when comparing data from the first portion of the sleep period, but restricted to recovery sleep if the entire sleep episode was considered. Period-amplitude analysis was less dependent on the quantity of NREM sleep utilized, and demonstrated topographic changes in the count, amplitude, and distribution of slow waves, with frontal increases in slow wave amplitude, numbers of high-amplitude waves, and amplitude/slopes of low amplitude waves resulting from partial sleep deprivation. Topographic changes in slow waves occur across the course of partial sleep restriction and recovery. These results demonstrate a homeostatic response to partial sleep loss in humans. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  12. The nonlinear theory of slow-wave electron cyclotron masers with inclusion of the beam velocity spread

    International Nuclear Information System (INIS)

    Kong, Ling-Bao; Wang, Hong-Yu; Hou, Zhi-Ling; Jin, Hai-Bo; Du, Chao-Hai

    2013-01-01

    The nonlinear theory of slow-wave electron cyclotron masers (ECM) with an initially straight electron beam is developed. The evolution equation of the nonlinear beam electron energy is derived. The numerical studies of the slow-wave ECM efficiency with inclusion of Gaussian beam velocity spread are presented. It is shown that the velocity spread reduces the interaction efficiency. -- Highlights: •The theory of slow-wave electron cyclotron masers is considered. •The calculation of efficiency under the resonance condition is presented. •The efficiency under Gaussian velocity spreads has been obtained

  13. The nonlinear theory of slow-wave electron cyclotron masers with inclusion of the beam velocity spread

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Ling-Bao, E-mail: konglingbao@gmail.com [School of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Key Laboratory of Environmentally Harmful Chemicals Assessment, Beijing University of Chemical Technology, Beijing 100029 (China); Wang, Hong-Yu [School of Physics, Anshan Normal University, Anshan 114005 (China); Hou, Zhi-Ling, E-mail: houzl@mail.buct.edu.cn [School of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Key Laboratory of Environmentally Harmful Chemicals Assessment, Beijing University of Chemical Technology, Beijing 100029 (China); Jin, Hai-Bo [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Du, Chao-Hai [Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China)

    2013-12-15

    The nonlinear theory of slow-wave electron cyclotron masers (ECM) with an initially straight electron beam is developed. The evolution equation of the nonlinear beam electron energy is derived. The numerical studies of the slow-wave ECM efficiency with inclusion of Gaussian beam velocity spread are presented. It is shown that the velocity spread reduces the interaction efficiency. -- Highlights: •The theory of slow-wave electron cyclotron masers is considered. •The calculation of efficiency under the resonance condition is presented. •The efficiency under Gaussian velocity spreads has been obtained.

  14. Social exclusion in middle childhood: rejection events, slow-wave neural activity, and ostracism distress.

    Science.gov (United States)

    Crowley, Michael J; Wu, Jia; Molfese, Peter J; Mayes, Linda C

    2010-01-01

    This study examined neural activity with event-related potentials (ERPs) in middle childhood during a computer-simulated ball-toss game, Cyberball. After experiencing fair play initially, children were ultimately excluded by the other players. We focused specifically on “not my turn” events within fair play and rejection events within social exclusion. Dense-array ERPs revealed that rejection events are perceived rapidly. Condition differences (“not my turn” vs. rejection) were evident in a posterior ERP peaking at 420 ms consistent, with a larger P3 effect for rejection events indicating that in middle childhood rejection events are differentiated in <500 ms. Condition differences were evident for slow-wave activity (500-900 ms) in the medial frontal cortical region and the posterior occipital-parietal region, with rejection events more negative frontally and more positive posteriorly. Distress from the rejection experience was associated with a more negative frontal slow wave and a larger late positive slow wave, but only for rejection events. Source modeling with Geosouce software suggested that slow-wave neural activity in cortical regions previously identified in functional imaging studies of ostracism, including subgenual cortex, ventral anterior cingulate cortex, and insula, was greater for rejection events vs. “not my turn” events. © 2010 Psychology Press

  15. A miniature bidirectional telemetry system for in vivo gastric slow wave recordings

    International Nuclear Information System (INIS)

    Farajidavar, Aydin; Chiao, J-C; O'Grady, Gregory; Rao, Smitha M N; Cheng, Leo K; Abell, Thomas

    2012-01-01

    Stomach contractions are initiated and coordinated by an underlying electrical activity (slow waves), and electrical dysrhythmias accompany motility diseases. Electrical recordings taken directly from the stomach provide the most valuable data, but face technical constraints. Serosal or mucosal electrodes have cables that traverse the abdominal wall, or a natural orifice, causing discomfort and possible infection, and restricting mobility. These problems motivated the development of a wireless system. The bidirectional telemetric system constitutes a front-end transponder, a back-end receiver and a graphical user interface. The front-end module conditions the analogue signals, then digitizes and loads the data into a radio for transmission. Data receipt at the back-end is acknowledged via a transceiver function. The system was validated in a bench-top study, then validated in vivo using serosal electrodes connected simultaneously to a commercial wired system. The front-end module was 35 × 35 × 27 mm 3 and weighed 20 g. Bench-top tests demonstrated reliable communication within a distance range of 30 m, power consumption of 13.5 mW, and 124 h operation when utilizing a 560 mAh, 3 V battery. In vivo, slow wave frequencies were recorded identically with the wireless and wired reference systems (2.4 cycles min −1 ), automated activation time detection was modestly better for the wireless system (5% versus 14% FP rate), and signal amplitudes were modestly higher via the wireless system (462 versus 386 µV; p < 0.001). This telemetric system for slow wave acquisition is reliable, power efficient, readily portable and potentially implantable. The device will enable chronic monitoring and evaluation of slow wave patterns in animals and patients. (note)

  16. RF generated currents in a magnetized plasma using a slow wave structure

    International Nuclear Information System (INIS)

    Poole, B.R.; Cheo, B.R.; Kuo, S.P.; Tang, M.G.

    1983-01-01

    The generation of a dc current in a plasma by using RF waves is of importance for the operation of steadystate toroidal devices. An experimental investigation in the use of unidirectional, low frequency RF waves to drive currents has been made. Instead of using a natural plasma wave a slow wave guiding structure is used along the entire length of the plasma. When the RF wave is injected an increase in ionization and T/sub e/, and hence the background current is observed. However, the change depends on wave direction: The +k/sub z/ excitation yields a much larger electron current compared with the -k/sub z/ excitation indicating a net wave driven current. The measured modification in electron density and T/sub e/ is independent of wave direction. The current with a standing wave excitation generally falls at the average of the travelling wave (+ or - k/sub z/) driven currents. The net wave driven current is proportional to the feed power at approx. = 10 mA/kW. No saturation of the current is observed with feed powers up to 1 kW. Since the exciting structure is only 1 wavelength long, its k/sub z/ spectrum is relatively broad and hence no sharp resonances are observed as various plasma parameters and B/sub O/ are changed. There is no measurable difference between the power absorbed by the load resistors and the input power to the slow wave structure. Thus the current is driven by the wave field exclamation E exclamation 2 rather than the power absorbed in the plasma. The theoretical background and the physical mechanism is presented

  17. A prospective study of levetiracetam efficacy in epileptic syndromes with continuous spikes-waves during slow sleep

    DEFF Research Database (Denmark)

    Atkins, Mary; Nikanorova, Marina

    2011-01-01

    To evaluate the add-on effect of levetiracetam (LEV) treatment on the EEG and clinical status of children with continuous spikes-waves during slow sleep (CSWS).......To evaluate the add-on effect of levetiracetam (LEV) treatment on the EEG and clinical status of children with continuous spikes-waves during slow sleep (CSWS)....

  18. Alterations in myoelectric activity of the small bowel in rabbits after transarterial embolization

    International Nuclear Information System (INIS)

    Ai Songtao; Wang Xiaolin; Gong Gaoquan; Chen Yi; Lin Genlai; Zhang Feng; Li Guoping; Liu Lingxiao

    2005-01-01

    Objective: To explore alterations in myoelectric activity of the small bowel in rabbits after transarterial embolization and provide academic basis for assessing bowel viability and management. Methods: Twenty normal rabbits were selected and divided into three groups (2 mg group, n=10; 6 mg group, n=5; control group, n=5). Members of 2 mg group were embolized with PVA 2 mg, those of 6 mg group with PVA 6 mg, and the control group with normal saline 2 ml. After microcatherization embolization, myoelectric activity of the small bowel was recorded for 24 hr using chronically implanted electrodes in conscious rabbits. Results: In 2 mg group, the frequency and the amplitude of slow wave of proximal jejunum were significantly lower in post-embolization period than pre-embolization period [(17.83±0.55) cpm vs (11.59±0.23) cpm(P 0.05) and (0.1632±0.002) mV vs (0.1606±0.003) mV (P>0.05), respectively]. Conclusions: Embolization with PVA evokes significant and passive effect on basal electrical rhythm of small bowel. It could provide academic basis for assessing bowel viability to interventional embolization. (authors)

  19. First Imaging Observation of Standing Slow Wave in Coronal Fan Loops

    International Nuclear Information System (INIS)

    Pant, V.; Tiwari, A.; Banerjee, D.; Yuan, D.

    2017-01-01

    We observe intensity oscillations along coronal fan loops associated with the active region AR 11428. The intensity oscillations were triggered by blast waves that were generated due to X-class flares in the distant active region AR 11429. To characterize the nature of oscillations, we created time–distance maps along the fan loops and noted that the intensity oscillations at two ends of the loops were out of phase. As we move along the fan loop, the amplitude of the oscillations first decreased and then increased. The out-of-phase nature together with the amplitude variation along the loop implies that these oscillations are very likely to be standing waves. The period of the oscillations is estimated to be ∼27 minutes, damping time to be ∼45 minutes, and phase velocity projected in the plane of sky to be ∼65–83 km s"−"1. The projected phase speeds were in the range of the acoustic speed of coronal plasma at about 0.6 MK, which further indicates that these are slow waves. To the best of our knowledge, this is the first report on the existence of the standing slow waves in non-flaring fan loops.

  20. First Imaging Observation of Standing Slow Wave in Coronal Fan Loops

    Energy Technology Data Exchange (ETDEWEB)

    Pant, V.; Tiwari, A.; Banerjee, D. [Indian Institute of Astrophysics, Bangalore 560 034 (India); Yuan, D. [Institute of Space Science and Applied Technology, Harbin Institute of Technology, Shenzhen 518000 (China)

    2017-09-20

    We observe intensity oscillations along coronal fan loops associated with the active region AR 11428. The intensity oscillations were triggered by blast waves that were generated due to X-class flares in the distant active region AR 11429. To characterize the nature of oscillations, we created time–distance maps along the fan loops and noted that the intensity oscillations at two ends of the loops were out of phase. As we move along the fan loop, the amplitude of the oscillations first decreased and then increased. The out-of-phase nature together with the amplitude variation along the loop implies that these oscillations are very likely to be standing waves. The period of the oscillations is estimated to be ∼27 minutes, damping time to be ∼45 minutes, and phase velocity projected in the plane of sky to be ∼65–83 km s{sup −1}. The projected phase speeds were in the range of the acoustic speed of coronal plasma at about 0.6 MK, which further indicates that these are slow waves. To the best of our knowledge, this is the first report on the existence of the standing slow waves in non-flaring fan loops.

  1. Discrete-State Simulated Annealing For Traveling-Wave Tube Slow-Wave Circuit Optimization

    Science.gov (United States)

    Wilson, Jeffrey D.; Bulson, Brian A.; Kory, Carol L.; Williams, W. Dan (Technical Monitor)

    2001-01-01

    Algorithms based on the global optimization technique of simulated annealing (SA) have proven useful in designing traveling-wave tube (TWT) slow-wave circuits for high RF power efficiency. The characteristic of SA that enables it to determine a globally optimized solution is its ability to accept non-improving moves in a controlled manner. In the initial stages of the optimization, the algorithm moves freely through configuration space, accepting most of the proposed designs. This freedom of movement allows non-intuitive designs to be explored rather than restricting the optimization to local improvement upon the initial configuration. As the optimization proceeds, the rate of acceptance of non-improving moves is gradually reduced until the algorithm converges to the optimized solution. The rate at which the freedom of movement is decreased is known as the annealing or cooling schedule of the SA algorithm. The main disadvantage of SA is that there is not a rigorous theoretical foundation for determining the parameters of the cooling schedule. The choice of these parameters is highly problem dependent and the designer needs to experiment in order to determine values that will provide a good optimization in a reasonable amount of computational time. This experimentation can absorb a large amount of time especially when the algorithm is being applied to a new type of design. In order to eliminate this disadvantage, a variation of SA known as discrete-state simulated annealing (DSSA), was recently developed. DSSA provides the theoretical foundation for a generic cooling schedule which is problem independent, Results of similar quality to SA can be obtained, but without the extra computational time required to tune the cooling parameters. Two algorithm variations based on DSSA were developed and programmed into a Microsoft Excel spreadsheet graphical user interface (GUI) to the two-dimensional nonlinear multisignal helix traveling-wave amplifier analysis program TWA3

  2. Preliminary study of slow and fast ultrasonic waves using MR images of trabecular bone phantom

    Energy Technology Data Exchange (ETDEWEB)

    Solis-Najera, S. E., E-mail: solisnajera@ciencias.unam.mx, E-mail: angel.perez@ciencias.unam.mx, E-mail: lucia.medina@ciencias.unam.mx; Neria-Pérez, J. A., E-mail: solisnajera@ciencias.unam.mx, E-mail: angel.perez@ciencias.unam.mx, E-mail: lucia.medina@ciencias.unam.mx; Medina, L., E-mail: solisnajera@ciencias.unam.mx, E-mail: angel.perez@ciencias.unam.mx, E-mail: lucia.medina@ciencias.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, México, DF 04510 (Mexico); Garipov, R., E-mail: ruslan.garipov@mrsolutions.co.uk [MR Solutions Ltd, Surrey (United Kingdom); Rodríguez, A. O., E-mail: arog@xanum.uam.mx [Departamento Ingeniería Eléctrica, Universidad Autónoma Metropolitana Iztapalapa, México, DF 09340 (Mexico)

    2014-11-07

    Cancellous bone is a complex tissue that performs physiological and biomechanical functions in all vertebrates. It is made up of trabeculae that, from a simplified structural viewpoint, can be considered as plates and beams in a hyperstatic structure that change with time leading to osteoporosis. Several methods has been developed to study the trabecular bone microstructure among them is the Biot’s model which predicts the existence of two longitudinal waves in porous media; the slow and the fast waves, that can be related to porosity of the media. This paper is focused on the experimental detection of the two Biot’s waves of a trabecular bone phantom, consisting of a trabecular network of inorganic hydroxyapatite. Experimental measurements of both waves were performed using through transmission ultrasound. Results had shown clearly that the propagation of two waves propagation is transversal to the trabecular alignment. Otherwise the waves are overlapped and a single wave seems to be propagated. To validate these results, magnetic resonance images were acquired to assess the trabecular direction, and to assure that the pulses correspond to the slow and fast waves. This approach offers a methodology for non-invasive studies of trabecular bones.

  3. Modulational instability and associated rogue structures of slow magnetosonic wave in Hall magnetohydrodynamic plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Panwar, Anuraj; Ryu, Chang-Mo [Department of Physics, POSTECH, Hyoja-Dong San 31, KyungBuk, Pohang 790-784 (Korea, Republic of)

    2014-06-15

    The modulational instability and associated rogue structures of a slow magnetosonic wave are investigated for a Hall magnetohydrodynamic plasma. Nonlinear Schrodinger equation is obtained by using the multiple scale method, which shows a modulationally unstable slow magnetosonic mode evolving into bright wavepackets. The dispersive effects induced by the Hall electron current increase with the increase in plasma β and become weaker as the angle of propagation increases. The growth rate of the modulational instability also increases with the increase in plasma β. The growth rate is greatest for the parallel propagation and drops to zero for perpendicular propagation. The envelope wavepacket of a slow magnetosonic is widened with less oscillations as plasma β increases. But the wavepacket becomes slightly narrower and more oscillatory as the angle of propagation increases. Further a non-stationary envelope solution of the Peregrine soliton is analyzed for rogue waves. The Peregrine soliton contracts temporally and expands spatially with increase in plasma β. However, the width of a slow magnetosonic Peregrine soliton decreases both temporally and spatially with increase of the propagation angle.

  4. A system and method for online high-resolution mapping of gastric slow-wave activity.

    Science.gov (United States)

    Bull, Simon H; O'Grady, Gregory; Du, Peng; Cheng, Leo K

    2014-11-01

    High-resolution (HR) mapping employs multielectrode arrays to achieve spatially detailed analyses of propagating bioelectrical events. A major current limitation is that spatial analyses must currently be performed "off-line" (after experiments), compromising timely recording feedback and restricting experimental interventions. These problems motivated development of a system and method for "online" HR mapping. HR gastric recordings were acquired and streamed to a novel software client. Algorithms were devised to filter data, identify slow-wave events, eliminate corrupt channels, and cluster activation events. A graphical user interface animated data and plotted electrograms and maps. Results were compared against off-line methods. The online system analyzed 256-channel serosal recordings with no unexpected system terminations with a mean delay 18 s. Activation time marking sensitivity was 0.92; positive predictive value was 0.93. Abnormal slow-wave patterns including conduction blocks, ectopic pacemaking, and colliding wave fronts were reliably identified. Compared to traditional analysis methods, online mapping had comparable results with equivalent coverage of 90% of electrodes, average RMS errors of less than 1 s, and CC of activation maps of 0.99. Accurate slow-wave mapping was achieved in near real-time, enabling monitoring of recording quality and experimental interventions targeted to dysrhythmic onset. This work also advances the translation of HR mapping toward real-time clinical application.

  5. Calculation of coupling to slow and fast waves in the LHRF from phased waveguide arrays

    International Nuclear Information System (INIS)

    Pinsker, R.I.; Duvall, R.E.; Fortgang, C.M.; Colestock, P.L.

    1986-04-01

    A previously reported algorithm for solving the problem of coupling electromagnetic energy in the LHRF from a phased array of identical rectangular waveguides to a plane-stratified, magnetized cold plasma is numerically implemented. The resulting computer codes are sufficiently general to allow for an arbitrary number of waveguides with finite dimensions in both poloidal and toroidal directions, and are thus capable of computing coupling to both slow and fast waves in the plasma. Some of the details of the implementation and the extension of the algorithm to allow study of the Fourier spectrum of slow and fast waves launched by the array are discussed. Good agreement is found with previously reported, less general work for the slow wave launching case. The effect of phasing multirow arrays in the poloidal direction is studied, and an asymmetry between phasing 'up' and 'down' is found that persists in the case where the plasma adjacent to the array is uniform. A 4 x 3 array designed to launch fast waves of high phase velocity is studied. By using the optimal poloidal phasing, low reflection coefficients (absolute value of R 2 less than or equal to 20%) are found under some not unrealistic edge plasma conditions, but most of the input power is trapped in the outermost layer of the plasma. Implications of our results for fast wave current drive experiments are discussed

  6. On the possibility of the autoresonant motion of an electron in a slow electromagnetic wave

    International Nuclear Information System (INIS)

    Milantiev, V.P.

    1994-01-01

    By autoresonant motion one usually means the motion when the condition of cyclotron resonance of gyrating particle with electromagnetic wave is conserved during all the time of the motion in spite of the relativistic mass increase. Such a motion takes place only in the case of vacuum wave, when the phase velocity ν p is equal to the speed of light in a vacuum C. Otherwise autoresonance is impossible, and energy of the particle oscillates in time. The authors now discuss the possibility of the autoresonance in a slow electromagnetic wave (ν p < c) propagating along the straight lines of the external magnetic field. It turns out that the autoresonant regime of the motion in a slow electromagnetic wave possible if some rather restrictive relations between the electric drift velocity and the phase velocity of wave take place. It depends also on the polarization of wave. The general case of the elliptical polarization is considered. The optimal regime corresponds to the wave with linear polarization in the direction of the constant electric field. For this case the calculations show that energy of the particle can unlimitedly increase (or decrease). The rate of acceleration can be even larger than in the case of vacuum wave. Radiation forces will restrict this process

  7. Comparative Study between Slow Shock Wave Lithotripsy and Fast Shock Wave Lithotripsy in the Management of Renal Stone

    Directory of Open Access Journals (Sweden)

    AKM Zamanul Islam Bhuiyan

    2013-01-01

    Full Text Available Background: Renal calculi are frequent causes of ureteric colic. Extracorporeal shock wave lithotripsy is the most common treatment of these stones. It uses focused sound waves to break up stones externally. Objective: To compare the efficiency of slow and fast delivery rate of shock waves on stone fragmentation and treatment outcome in patients with renal calculi. Materials and Methods: This prospective study was done in the department of Urology, National Institute of Kidney diseases and Urology, Sher-e-Bangla Nagar, Dhaka from July 2006 to June 2007. Total 90 patients were treated using the Storz Medical Modulith ® SLX lithotripter. Patients were divided into Group A, Group B and Group C – each group having 30 subjects. Group A was selected for extracorporeal shockwave lithotripsy (ESWL by 60 shock waves per minute, Group B by 90 shock waves per minute and Group C by 120 shock waves per minute. Results: Complete clearance of stone was observed in 24 patients in Group A and 13 patients in both Group B and Group C in first session. In Group A only 3 patients needed second session but in Group B and Group C, 12 and 8 patients needed second session. In Group A only one patient needed third session but third session was required for 3 patients in Group B and 5 patients in Group C for complete clearance of stone. In Group A, subsequent sessions were performed under spinal anesthesia and in Group B under sedation and analgesia (p>0.001. Mean number of sessions for full clearance of stones in group A was 1.37 ± 0.85, in Group B was 1.8 ± 0.887 and in Group C was 2.0 ± 1.083. Significant difference was observed in term of sessions among groups (p>0.05. In first follow-up, complete clearance of stones was seen in 24 patients in Group A and 13 in both Group B and Group C. In second follow-up, 3 patients in Group A, 12 in Group B and 8 in Group C showed complete clearance of stones. It was observed that rate of stone clearance was higher in Group A

  8. Neuronal Networks in Children with Continuous Spikes and Waves during Slow Sleep

    Science.gov (United States)

    Siniatchkin, Michael; Groening, Kristina; Moehring, Jan; Moeller, Friederike; Boor, Rainer; Brodbeck, Verena; Michel, Christoph M.; Rodionov, Roman; Lemieux, Louis; Stephani, Ulrich

    2010-01-01

    Epileptic encephalopathy with continuous spikes and waves during slow sleep is an age-related disorder characterized by the presence of interictal epileptiform discharges during at least greater than 85% of sleep and cognitive deficits associated with this electroencephalography pattern. The pathophysiological mechanisms of continuous spikes and…

  9. Relationships between gastric slow wave frequency, velocity, and extracellular amplitude studied by a joint experimental-theoretical approach.

    Science.gov (United States)

    Wang, T H-H; Du, P; Angeli, T R; Paskaranandavadivel, N; Erickson, J C; Abell, T L; Cheng, L K; O'Grady, G

    2018-01-01

    Gastric slow wave dysrhythmias are accompanied by deviations in frequency, velocity, and extracellular amplitude, but the inherent association between these parameters in normal activity still requires clarification. This study quantified these associations using a joint experimental-theoretical approach. Gastric pacing was conducted in pigs with simultaneous high-resolution slow wave mapping (32-256 electrodes; 4-7.6 mm spacing). Relationships between period, velocity, and amplitude were quantified and correlated for each wavefront. Human data from two existing mapping control cohorts were analyzed to extract and correlate these same parameters. A validated biophysically based ICC model was also applied in silico to quantify velocity-period relationships during entrainment simulations and velocity-amplitude relationships from membrane potential equations. Porcine pacing studies identified positive correlations for velocity-period (0.13 mm s -1 per 1 s, r 2 =.63, Prelationships and demonstrated dependence on the slow wave recovery phase. Simulated membrane potential relationships were close to these experimental results (100 μV per 1 mm s -1 ). These data quantify the relationships between slow wave frequency, velocity, and extracellular amplitude. The results from both human and porcine studies were in keeping with biophysical models, demonstrating concordance with ICC biophysics. These relationships are important in the regulation of gastric motility and will help to guide interpretations of dysrhythmias. © 2017 John Wiley & Sons Ltd.

  10. Costs of storing colour and complex shape in visual working memory: Insights from pupil size and slow waves.

    Science.gov (United States)

    Kursawe, Michael A; Zimmer, Hubert D

    2015-06-01

    We investigated the impact of perceptual processing demands on visual working memory of coloured complex random polygons during change detection. Processing load was assessed by pupil size (Exp. 1) and additionally slow wave potentials (Exp. 2). Task difficulty was manipulated by presenting different set sizes (1, 2, 4 items) and by making different features (colour, shape, or both) task-relevant. Memory performance in the colour condition was better than in the shape and both condition which did not differ. Pupil dilation and the posterior N1 increased with set size independent of type of feature. In contrast, slow waves and a posterior P2 component showed set size effects but only if shape was task-relevant. In the colour condition slow waves did not vary with set size. We suggest that pupil size and N1 indicates different states of attentional effort corresponding to the number of presented items. In contrast, slow waves reflect processes related to encoding and maintenance strategies. The observation that their potentials vary with the type of feature (simple colour versus complex shape) indicates that perceptual complexity already influences encoding and storage and not only comparison of targets with memory entries at the moment of testing. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Rats Housed on Corncob Bedding Show Less Slow-Wave Sleep

    OpenAIRE

    Leys, Laura J; McGaraughty, Steve; Radek, Richard J

    2012-01-01

    Despite the reported advantages of corncob bedding, questions have emerged about how comfortable animals find this type of bedding as a resting surface. In this study, encephalography (EEG) was used to compare the effects of corncob and aspen-chip bedding on rat slow-wave sleep (SWS). According to a facility-wide initiative, rats that were weaned on aspen-chip bedding were switched to corncob bedding in home cages and EEG recording chambers. Spontaneous EEG recordings obtained for 5 wk after ...

  12. Slow waves, sharp waves, ripples, and REM in sleeping dragons.

    Science.gov (United States)

    Shein-Idelson, Mark; Ondracek, Janie M; Liaw, Hua-Peng; Reiter, Sam; Laurent, Gilles

    2016-04-29

    Sleep has been described in animals ranging from worms to humans. Yet the electrophysiological characteristics of brain sleep, such as slow-wave (SW) and rapid eye movement (REM) activities, are thought to be restricted to mammals and birds. Recording from the brain of a lizard, the Australian dragon Pogona vitticeps, we identified SW and REM sleep patterns, thus pushing back the probable evolution of these dynamics at least to the emergence of amniotes. The SW and REM sleep patterns that we observed in lizards oscillated continuously for 6 to 10 hours with a period of ~80 seconds. The networks controlling SW-REM antagonism in amniotes may thus originate from a common, ancient oscillator circuit. Lizard SW dynamics closely resemble those observed in rodent hippocampal CA1, yet they originate from a brain area, the dorsal ventricular ridge, that has no obvious hodological similarity with the mammalian hippocampus. Copyright © 2016, American Association for the Advancement of Science.

  13. Slow [Na+]i dynamics impacts arrhythmogenesis and spiral wave reentry in cardiac myocyte ionic model.

    Science.gov (United States)

    Krogh-Madsen, Trine; Christini, David J

    2017-09-01

    Accumulation of intracellular Na + is gaining recognition as an important regulator of cardiac myocyte electrophysiology. The intracellular Na + concentration can be an important determinant of the cardiac action potential duration, can modulate the tissue-level conduction of excitation waves, and can alter vulnerability to arrhythmias. Mathematical models of cardiac electrophysiology often incorporate a dynamic intracellular Na + concentration, which changes much more slowly than the remaining variables. We investigated the dependence of several arrhythmogenesis-related factors on [Na + ] i in a mathematical model of the human atrial action potential. In cell simulations, we found that [Na + ] i accumulation stabilizes the action potential duration to variations in several conductances and that the slow dynamics of [Na + ] i impacts bifurcations to pro-arrhythmic afterdepolarizations, causing intermittency between different rhythms. In long-lasting tissue simulations of spiral wave reentry, [Na + ] i becomes spatially heterogeneous with a decreased area around the spiral wave rotation center. This heterogeneous region forms a functional anchor, resulting in diminished meandering of the spiral wave. Our findings suggest that slow, physiological, rate-dependent variations in [Na + ] i may play complex roles in cellular and tissue-level cardiac dynamics.

  14. Coronal Seismology of Flare-Excited Standing Slow-Mode Waves Observed by SDO/AIA

    Science.gov (United States)

    Wang, Tongjiang; Ofman, Leon; Davila, Joseph M.

    2016-05-01

    Flare-excited longitudinal intensity oscillations in hot flaring loops have been recently detected by SDO/AIA in 94 and 131 Å bandpasses. Based on the interpretation in terms of a slow-mode wave, quantitative evidence of thermal conduction suppression in hot (>9 MK) loops has been obtained for the first time from measurements of the polytropic index and phase shift between the temperature and density perturbations (Wang et al. 2015, ApJL, 811, L13). This result has significant implications in two aspects. One is that the thermal conduction suppression suggests the need of greatly enhanced compressive viscosity to interpret the observed strong wave damping. The other is that the conduction suppression provides a reasonable mechanism for explaining the long-duration events where the thermal plasma is sustained well beyond the duration of impulsive hard X-ray bursts in many flares, for a time much longer than expected by the classical Spitzer conductive cooling. In this study, we model the observed standing slow-mode wave in Wang et al. (2015) using a 1D nonlinear MHD code. With the seismology-derived transport coefficients for thermal conduction and compressive viscosity, we successfully simulate the oscillation period and damping time of the observed waves. Based on the parametric study of the effect of thermal conduction suppression and viscosity enhancement on the observables, we discuss the inversion scheme for determining the energy transport coefficients by coronal seismology.

  15. Optimization of relativistic backward wave oscillator with non-uniform slow wave structure and a resonant reflector

    International Nuclear Information System (INIS)

    Chen, Zaigao; Wang, Jianguo; Wang, Yue

    2015-01-01

    This letter optimizes synchronously 18 parameters of a relativistic backward wave oscillator with non-uniform slow wave structure (SWS) and a resonant reflector by using the parallel genetic algorithms and particle-in-cell simulation. The optimization results show that the generation efficiency of microwave from the electron beam has increased 32% compared to that of the original device. After optimization, the electromagnetic mode propagating in the resonant changes from the original TM 020 mode of reflector to higher-order TM 021 mode, which has a high reflection coefficient in a broader frequency range than that of the former. The modulation of current inside the optimized device is much deeper than that in the original one. The product of the electric field and current is defined. Observing this product, it is found that the interaction of the electron beam with the electromagnetic wave in the optimized device is much stronger than that in the original device, and at the rear part of SWS of the optimized device, the electron beam dominantly gives out the energy to the electromagnetic wave, leading to the higher generation efficiency of microwave than that of the original device

  16. Slow-wave sleep estimation on a load-cell-installed bed: a non-constrained method

    International Nuclear Information System (INIS)

    Choi, Byung Hun; Chung, Gih Sung; Lee, Jin-Seong; Jeong, Do-Un; Park, Kwang Suk

    2009-01-01

    Polysomnography (PSG) involves simultaneous and continuous monitoring of relevant normal and abnormal physiological activity during sleep. At present, an electroencephalography-based rule is generally used for classifying sleep stages. However, scoring the PSG record is quite laborious and time consuming. In this paper, movement and cardiac activity were measured unobtrusively by a load-cell-installed bed, and sleep was classified into two stages: slow-wave sleep and non-slow-wave sleep. From the measured cardiac activity, we extracted heartbeat data and calculated heart rate variability parameters: standard deviation of R–R intervals SDNN, low frequency-to-high frequency ratio, alpha of detrended fluctuation analysis and correlation coefficient of R–R interval. The developed system showed a substantial concordance with PSG results when compared using a contingency test. The mean epoch-by-epoch agreement between the proposed method and PSG was 92.5% and Cohen's kappa was 0.62

  17. Slow-wave propagation and sheath interaction in the ion-cyclotron frequency range

    International Nuclear Information System (INIS)

    Myra, J R; D'Ippolito, D A

    2010-01-01

    In previous work (Myra J R and D'Ippolito D A 2008 Phys. Rev. Lett. 101 195004) we studied the propagation of slow-wave (SW) resonance cones launched parasitically by a fast-wave antenna into a tenuous magnetized plasma. Here we extend the treatment of SW propagation and sheath interaction to 'dense' scrape-off-layer plasmas where the usual cold-plasma SW is evanescent. Using the sheath boundary condition, it is shown that for sufficiently close limiters, the SW couples to a sheath-plasma wave and is no longer evanescent, but radially propagating. A self-consistent calculation of the rf-sheath width yields the resulting sheath voltage in terms of the amplitude of the launched SW, plasma parameters and connection length. The conditions for avoiding potentially deleterious rf-wall interactions in tokamak rf heating experiments are summarized.

  18. Slow-wave metamaterial open panels for efficient reduction of low-frequency sound transmission

    Science.gov (United States)

    Yang, Jieun; Lee, Joong Seok; Lee, Hyeong Rae; Kang, Yeon June; Kim, Yoon Young

    2018-02-01

    Sound transmission reduction is typically governed by the mass law, requiring thicker panels to handle lower frequencies. When open holes must be inserted in panels for heat transfer, ventilation, or other purposes, the efficient reduction of sound transmission through holey panels becomes difficult, especially in the low-frequency ranges. Here, we propose slow-wave metamaterial open panels that can dramatically lower the working frequencies of sound transmission loss. Global resonances originating from slow waves realized by multiply inserted, elaborately designed subwavelength rigid partitions between two thin holey plates contribute to sound transmission reductions at lower frequencies. Owing to the dispersive characteristics of the present metamaterial panels, local resonances that trap sound in the partitions also occur at higher frequencies, exhibiting negative effective bulk moduli and zero effective velocities. As a result, low-frequency broadened sound transmission reduction is realized efficiently in the present metamaterial panels. The theoretical model of the proposed metamaterial open panels is derived using an effective medium approach and verified by numerical and experimental investigations.

  19. REFLECTION OF PROPAGATING SLOW MAGNETO-ACOUSTIC WAVES IN HOT CORONAL LOOPS: MULTI-INSTRUMENT OBSERVATIONS AND NUMERICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Sudip; Banerjee, Dipankar; Pant, Vaibhav [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India); Yuan, Ding; Fang, Xia; Doorsselaere, Tom Van, E-mail: sudip@iiap.res.in, E-mail: xia.fang@wis.kuleuven.be [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, bus 2400, 3001, Leuven (Belgium)

    2016-09-10

    Slow MHD waves are important tools for understanding coronal structures and dynamics. In this paper, we report a number of observations from the X-Ray Telescope (XRT) on board HINODE and Solar Dynamic Observatory /Atmospheric Imaging Assembly (AIA) of reflecting longitudinal waves in hot coronal loops. To our knowledge, this is the first report of this kind as seen from the XRT and simultaneously with the AIA. The wave appears after a micro-flare occurs at one of the footpoints. We estimate the density and temperature of the loop plasma by performing differential emission measure (DEM) analysis on the AIA image sequence. The estimated speed of propagation is comparable to or lower than the local sound speed, suggesting it to be a propagating slow wave. The intensity perturbation amplitude, in every case, falls very rapidly as the perturbation moves along the loop and eventually vanishes after one or more reflections. To check the consistency of such reflection signatures with the obtained loop parameters, we perform a 2.5D MHD simulation, which uses the parameters obtained from our observation as inputs, and perform forward modeling to synthesize AIA 94 Å images. Analyzing the synthesized images, we obtain the same properties of the observables as for the real observation. From the analysis we conclude that a footpoint heating can generate a slow wave which then reflects back and forth in the coronal loop before fading. Our analysis of the simulated data shows that the main agent for this damping is anisotropic thermal conduction.

  20. Glutamate microinjection in the medial septum of rats decreases paradoxical sleep and increases slow wave sleep.

    Science.gov (United States)

    Mukherjee, Didhiti; Kaushik, Mahesh K; Jaryal, Ashok Kumar; Kumar, Velayudhan Mohan; Mallick, Hruda Nanda

    2012-05-09

    The role of the medial septum in suppressing paradoxical sleep and promoting slow wave sleep was suggested on the basis of neurotoxic lesion studies. However, these conclusions need to be substantiated with further experiments, including chemical stimulation studies. In this report, the medial septum was stimulated in adult male rats by microinjection of L-glutamate. Sleep-wakefulness was electrophysiologically recorded, through chronically implanted electrodes, for 2 h before the injection and 4 h after the injection. There was a decrease in paradoxical sleep during the first hour and an increase in slow wave sleep during the second hour after the injection. The present findings not only supported the lesion studies but also showed that the major role of the medial septum is to suppress paradoxical sleep.

  1. Slow waves in microchannel metal waveguides and application to particle acceleration

    OpenAIRE

    L. C. Steinhauer; W. D. Kimura

    2003-01-01

    Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong ex...

  2. Role of slow oscillatory activity and slow wave sleep in consolidation of episodic-like memory in rats.

    Science.gov (United States)

    Oyanedel, Carlos N; Binder, Sonja; Kelemen, Eduard; Petersen, Kimberley; Born, Jan; Inostroza, Marion

    2014-12-15

    Our previous experiments showed that sleep in rats enhances consolidation of hippocampus dependent episodic-like memory, i.e. the ability to remember an event bound into specific spatio-temporal context. Here we tested the hypothesis that this enhancing effect of sleep is linked to the occurrence of slow oscillatory and spindle activity during slow wave sleep (SWS). Rats were tested on an episodic-like memory task and on three additional tasks covering separately the where (object place recognition), when (temporal memory), and what (novel object recognition) components of episodic memory. In each task, the sample phase (encoding) was followed by an 80-min retention interval that covered either a period of regular morning sleep or sleep deprivation. Memory during retrieval was tested using preferential exploration of novelty vs. familiarity. Consistent with previous findings, the rats which had slept during the retention interval showed significantly stronger episodic-like memory and spatial memory, and a trend of improved temporal memory (although not significant). Object recognition memory was similarly retained across sleep and sleep deprivation retention intervals. Recall of episodic-like memory was associated with increased slow oscillatory activity (0.85-2.0Hz) during SWS in the retention interval. Spatial memory was associated with increased proportions of SWS. Against our hypothesis, a relationship between spindle activity and episodic-like memory performance was not detected, but spindle activity was associated with object recognition memory. The results provide support for the role of SWS and slow oscillatory activity in consolidating hippocampus-dependent memory, the role of spindles in this process needs to be further examined. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Single-subject-based whole-brain MEG slow-wave imaging approach for detecting abnormality in patients with mild traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Ming-Xiong Huang

    2014-01-01

    Full Text Available Traumatic brain injury (TBI is a leading cause of sustained impairment in military and civilian populations. However, mild TBI (mTBI can be difficult to detect using conventional MRI or CT. Injured brain tissues in mTBI patients generate abnormal slow-waves (1–4 Hz that can be measured and localized by resting-state magnetoencephalography (MEG. In this study, we develop a voxel-based whole-brain MEG slow-wave imaging approach for detecting abnormality in patients with mTBI on a single-subject basis. A normative database of resting-state MEG source magnitude images (1–4 Hz from 79 healthy control subjects was established for all brain voxels. The high-resolution MEG source magnitude images were obtained by our recent Fast-VESTAL method. In 84 mTBI patients with persistent post-concussive symptoms (36 from blasts, and 48 from non-blast causes, our method detected abnormalities at the positive detection rates of 84.5%, 86.1%, and 83.3% for the combined (blast-induced plus with non-blast causes, blast, and non-blast mTBI groups, respectively. We found that prefrontal, posterior parietal, inferior temporal, hippocampus, and cerebella areas were particularly vulnerable to head trauma. The result also showed that MEG slow-wave generation in prefrontal areas positively correlated with personality change, trouble concentrating, affective lability, and depression symptoms. Discussion is provided regarding the neuronal mechanisms of MEG slow-wave generation due to deafferentation caused by axonal injury and/or blockages/limitations of cholinergic transmission in TBI. This study provides an effective way for using MEG slow-wave source imaging to localize affected areas and supports MEG as a tool for assisting the diagnosis of mTBI.

  4. Slowing of a fast electron beam in a plasma in an intense electromagnetic wave

    Energy Technology Data Exchange (ETDEWEB)

    Karapetyan, R.V.; Fedorov, M.V.

    1980-01-01

    The slowing of a fast electron beam as it penetrates into a plasma in a strong external electromagnetic field is studied. The effective collision frequency ..nu../sub p/ which is responsible for the slowing is derived in the dipole approximation; many-photon stimulated bremsstrahlung and inverse bremsstrahlung are taken into account. The asymptotic behavior of ..nu../sub p/ in strong wave fields E/sub 0/ is found. The results show that ..nu../sub p/ falls off with increasing E/sub 0/, because of a decrease in the frequency of collisions with plasma ions proportional to E/sub 0//sup -1/.

  5. Effect of Early Diagnosis and Treatment on the Prognosis of Children with Epilepsy Accompanied by Continuous Spikes and Waves during Slow Wave Sleep

    Directory of Open Access Journals (Sweden)

    Jiahua Ju

    2014-03-01

    Full Text Available Objective: To emphasize the importance of early diagnosis and treatment on the prognosis of children with epilepsy accompanied by continuous spikes and waves during slow wave sleep (CSCW. Methods: The clinical characteristics, electroencephalogram (ECG features, treatment and prognosis of 12 children with CSCW in our hospital were retrospectively analyzed, and the followup of 6 months to 4 years was given. Results: Imaging showed that 8 children suffered from brain lesions, while other 4 were normal. The initial onset of 10 children was at night, whereas 2 began with absence seizure in lucid interval, and they gradually appeared comprehensive brain function decline, meanwhile, ECG was characterized by continuous discharge during slow wave sleep. After 3 months of treatment with valproic acid, clonazepam, lamotrigine and hormones, the clinical symptoms and ECG of 10 children improved significantly, in which 3 ones recurred after 6 months of comprehensive treatment. Conclusion: The early manifestation of CSWS is untypical, and hence, early diagnosis and treatment can ameliorate the epileptic seizures of children, effectively inhibit epileptic electrical activity and has favorable prognosis.

  6. Remission of encephalopathy with status epilepticus (ESES) during sleep renormalizes regulation of slow wave sleep

    DEFF Research Database (Denmark)

    Bölsterli, Bigna K.; Gardella, Elena; Pavlidis, Elena

    2017-01-01

    Objective: In previous studies, we showed an altered overnight decrease of non–rapid-eye-movement (NREM) sleep slow waves in children with encephalopathy related to status epilepticus during sleep (ESES). Here, we test the hypothesis that these alterations renormalize after remission of ESES...

  7. Biomagnetic and bioelectric detection of gastric slow wave activity in normal human subjects—a correlation study

    International Nuclear Information System (INIS)

    Somarajan, S; Muszynski, N D; Obioha, C; Bradshaw, L A; Richards, W O

    2012-01-01

    We measured gastric slow wave activity simultaneously with a Superconducting Quantum Interference Device (SQUID) magnetometer, mucosal electrodes and cutaneous electrodes in 18 normal human subjects (11 women and 7 men). We processed signals with Fourier spectral analysis and SOBI blind-source separation techniques. We observed a high waveform correlation between the mucosal electromyogram (EMG) and multichannel SQUID magnetogastrogram (MGG). There was a lower waveform correlation between the mucosal EMG and cutaneous electrogastrogram (EGG), but the correlation improved with the application of SOBI. There was also a high correlation between the frequency of the electrical activity recorded in the MGG and in mucosal electrodes (r = 0.97). We concluded that SQUID magnetometers noninvasively record gastric slow wave activity that is highly correlated with the activity recorded by invasive mucosal electrodes. (paper)

  8. Effects of Low-frequency Current Sacral Dermatome Stimulation on Idiopathic Slow Transit Constipation.

    Science.gov (United States)

    Kim, Jin-Seop; Yi, Seung-Ju

    2014-06-01

    [Purpose] This study aimed to determine whether low-frequency current therapy can be used to reduce the symptoms of idiopathic slow transit constipation (ISTC). [Subjects] Fifteen patients (ten male and five female) with idiopathic slow transit constipation were enrolled in the present study. [Results] Bowel movements per day, bowel movements per week, and constipation assessment scale scores significantly improved after low-frequency current simulation of S2-S3. [Conclusion] Our results show that stimulation with low-frequency current of the sacral dermatomes may offer therapeutic benefits for a subject of patients with ISTC.

  9. Comparison of slowness profiles of lamb wave with elastic moduli and crystal structure in single crystalline silicon wafers

    Energy Technology Data Exchange (ETDEWEB)

    Min, Young Jae; Yun, Gyeong Won; Kim, Kyung Min; Roh, Yuji; Kim, Young H. [Applied Acoustics Lab, Korea Science Academy of KAIST, Busan (Korea, Republic of)

    2016-02-15

    Single crystalline silicon wafers having (100), (110), and (111) directions are employed as specimens for obtaining slowness profiles. Leaky Lamb waves (LLW) from immersed wafers were detected by varying the incident angles of the specimens and rotating the specimens. From an analysis of LLW signals for different propagation directions and phase velocities of each specimen, slowness profiles were obtained, which showed a unique symmetry with different symmetric axes. Slowness profiles were compared with elastic moduli of each wafer. They showed the same symmetries as crystal structures. In addition, slowness profiles showed expected patterns and values that can be inferred from elastic moduli. This implies that slowness profiles can be used to examine crystal structures of anisotropic solids.

  10. High power microwave source with a three dimensional printed metamaterial slow-wave structure

    International Nuclear Information System (INIS)

    French, David M.; Shiffler, Don

    2016-01-01

    For over the last decade, the concept of metamaterials has led to new approaches for considering the interaction of radiation with complex structures. However, practical manifestations of such a device operating at high power densities have proven difficult to achieve due to the resonant nature of metamaterials and the resultant high electric fields, which place severe constraints on manufacturing the slow wave structures. In this paper, we describe the first experimental manifestation of a high power microwave device utilizing a metallic slow wave structure (metamaterial-like) fabricated using additive manufacturing. The feasibility of utilizing additive manufacturing as a technique for building these relatively complicated structures has thus been demonstrated. The MW class microwave source operates in the C-band and shows frequency tunablility with electron beam voltage. The basic electromagnetic characteristics of this device, the construction using additive manufacturing, and the basic performance as a microwave oscillator are considered. Due to the tunable nature of the device, it shows promise not only as an oscillator but also as a microwave amplifier. Therefore, the dispersive characteristics and a discussion of the anticipated gain is included as it relates to an amplifier configuration.

  11. High power microwave source with a three dimensional printed metamaterial slow-wave structure

    Energy Technology Data Exchange (ETDEWEB)

    French, David M.; Shiffler, Don [Air Force Research Laboratory, Directed Energy Directorate, Albuquerque, New Mexico 871117 (United States)

    2016-05-15

    For over the last decade, the concept of metamaterials has led to new approaches for considering the interaction of radiation with complex structures. However, practical manifestations of such a device operating at high power densities have proven difficult to achieve due to the resonant nature of metamaterials and the resultant high electric fields, which place severe constraints on manufacturing the slow wave structures. In this paper, we describe the first experimental manifestation of a high power microwave device utilizing a metallic slow wave structure (metamaterial-like) fabricated using additive manufacturing. The feasibility of utilizing additive manufacturing as a technique for building these relatively complicated structures has thus been demonstrated. The MW class microwave source operates in the C-band and shows frequency tunablility with electron beam voltage. The basic electromagnetic characteristics of this device, the construction using additive manufacturing, and the basic performance as a microwave oscillator are considered. Due to the tunable nature of the device, it shows promise not only as an oscillator but also as a microwave amplifier. Therefore, the dispersive characteristics and a discussion of the anticipated gain is included as it relates to an amplifier configuration.

  12. Transabdominal Ultrasonography of the Small Bowel

    Directory of Open Access Journals (Sweden)

    Rudolf Kralik

    2013-01-01

    Full Text Available In the era of double balloon enteroscopy, capsule endoscopy, CT, and MRI enterography is transabdominal ultrasonography (TUS underestimated method for evaluation of small bowel pathology. As often initial imagine method in abdominal complaints, nowadays has TUS much better diagnostic potential than two decades ago. High-resolution ultrasound probes with harmonic imaging significantly improve resolution of bowel wall in real time, with possibility to asses bowel peristalsis. Color flow doppler enables evaluation of intramural bowel vascularisation, pulse wave doppler helps to quantificate flow in coeliac and superior mesenteric arteries. Small intestine contrast ultrasonography with oral contrast fluid, as well as contrast enhanced ultrasonography with intravenous microbubble contrast also improves small bowel imaging. We present a review of small intestine pathology that should be detected during ultrasound examinations, discuss technical requirements, advantages and limitations of TUS, typical ultrasound signs of Crohn's disease, ileus, celiac disease, intussusception, infectious enteritis, tumours, ischemic and haemorrhagic conditions of small bowel. In the hands of experienced investigator, despite some significant limitations(obesity, meteorism, is transabdominal ultrasonography reliable, noninvasive and inexpensive alternative method to computerised tomography (CT and magnetic resonance imaging (MRI in small bowel examination.

  13. Kinetic Alfven waves and electron physics. II. Oblique slow shocks

    International Nuclear Information System (INIS)

    Yin, L.; Winske, D.; Daughton, W.

    2007-01-01

    One-dimensional (1D) particle-in-cell (PIC; kinetic ions and electrons) and hybrid (kinetic ions; adiabatic and massless fluid electrons) simulations of highly oblique slow shocks (θ Bn =84 deg. and β=0.1) [Yin et al., J. Geophys. Res., 110, A09217 (2005)] have shown that the dissipation from the ions is too weak to form a shock and that kinetic electron physics is required. The PIC simulations also showed that the downstream electron temperature becomes anisotropic (T e parallel )>T e perpendicular ), as observed in slow shocks in space. The electron anisotropy results, in part, from the electron acceleration/heating by parallel electric fields of obliquely propagating kinetic Alfven waves (KAWs) excited by ion-ion streaming, which cannot be modeled accurately in hybrid simulations. In the shock ramp, spiky structures occur in density and electron parallel temperature, where the ion parallel temperature decreases due to the reduction of the ion backstreaming speed. In this paper, KAW and electron physics in oblique slow shocks are further examined under lower electron beta conditions. It is found that as the electron beta is reduced, the resonant interaction between electrons and the wave parallel electric fields shifts to the tail of the electron velocity distribution, providing more efficient parallel heating. As a consequence, for β e =0.02, the electron physics is shown to influence the formation of a θ Bn =75 deg. shock. Electron effects are further enhanced at a more oblique shock angle (θ Bn =84 deg.) when both the growth rate and the range of unstable modes on the KAW branch increase. Small-scale electron and ion phase-space vortices in the shock ramp formed by electron-KAW interactions and the reduction of the ion backstreaming speed, respectively, are observed in the simulations and confirmed in homogeneous geometries in one and two spatial dimensions in the accompanying paper [Yin et al., Phys. Plasmas 14, 062104 (2007)]. Results from this study

  14. Dynamics of nonlinear resonant slow MHD waves in twisted flux tubes

    Directory of Open Access Journals (Sweden)

    R. Erdélyi

    2002-01-01

    Full Text Available Nonlinear resonant magnetohydrodynamic (MHD waves are studied in weakly dissipative isotropic plasmas in cylindrical geometry. This geometry is suitable and is needed when one intends to study resonant MHD waves in magnetic flux tubes (e.g. for sunspots, coronal loops, solar plumes, solar wind, the magnetosphere, etc. The resonant behaviour of slow MHD waves is confined in a narrow dissipative layer. Using the method of simplified matched asymptotic expansions inside and outside of the narrow dissipative layer, we generalise the so-called connection formulae obtained in linear MHD for the Eulerian perturbation of the total pressure and for the normal component of the velocity. These connection formulae for resonant MHD waves across the dissipative layer play a similar role as the well-known Rankine-Hugoniot relations connecting solutions at both sides of MHD shock waves. The key results are the nonlinear connection formulae found in dissipative cylindrical MHD which are an important extension of their counterparts obtained in linear ideal MHD (Sakurai et al., 1991, linear dissipative MHD (Goossens et al., 1995; Erdélyi, 1997 and in nonlinear dissipative MHD derived in slab geometry (Ruderman et al., 1997. These generalised connection formulae enable us to connect solutions obtained at both sides of the dissipative layer without solving the MHD equations in the dissipative layer possibly saving a considerable amount of CPU-time when solving the full nonlinear resonant MHD problem.

  15. Reciprocal Influence of Slow Waves Extracted in Intracranial Pressure, Arterial Pressure and Cerebral Blood Velocity Signals

    National Research Council Canada - National Science Library

    Cervenansky, F

    2001-01-01

    ...), and arterial blood pressure (ABP). To clarify the links, we compared two frequency methods based on coherence function to estimate the influence of ICP, ABP, and CBV on couples, respectively CBV-ABP, ICP-CBV and ICP-ABP, of slow waves...

  16. Intracellular Ca(2+) release from endoplasmic reticulum regulates slow wave currents and pacemaker activity of interstitial cells of Cajal.

    Science.gov (United States)

    Zhu, Mei Hong; Sung, Tae Sik; O'Driscoll, Kate; Koh, Sang Don; Sanders, Kenton M

    2015-04-15

    Interstitial cells of Cajal (ICC) provide pacemaker activity in gastrointestinal muscles that underlies segmental and peristaltic contractions. ICC generate electrical slow waves that are due to large-amplitude inward currents resulting from anoctamin 1 (ANO1) channels, which are Ca(2+)-activated Cl(-) channels. We investigated the hypothesis that the Ca(2+) responsible for the stochastic activation of ANO1 channels during spontaneous transient inward currents (STICs) and synchronized activation of ANO1 channels during slow wave currents comes from intracellular Ca(2+) stores. ICC, obtained from the small intestine of Kit(+/copGFP) mice, were studied under voltage and current clamp to determine the effects of blocking Ca(2+) uptake into stores and release of Ca(2+) via inositol 1,4,5-trisphosphate (IP3)-dependent and ryanodine-sensitive channels. Cyclocpiazonic acid, thapsigargin, 2-APB, and xestospongin C inhibited STICs and slow wave currents. Ryanodine and tetracaine also inhibited STICs and slow wave currents. Store-active compounds had no direct effects on ANO1 channels expressed in human embryonic kidney-293 cells. Under current clamp, store-active drugs caused significant depolarization of ICC and reduced spontaneous transient depolarizations (STDs). After block of ryanodine receptors with ryanodine and tetracaine, repolarization did not restore STDs. ANO1 expressed in ICC has limited access to cytoplasmic Ca(2+) concentration, suggesting that pacemaker activity depends on Ca(2+) dynamics in restricted microdomains. Our data from studies of isolated ICC differ somewhat from studies on intact muscles and suggest that release of Ca(2+) from both IP3 and ryanodine receptors is important in generating pacemaker activity in ICC. Copyright © 2015 the American Physiological Society.

  17. Intracellular Ca2+ release from endoplasmic reticulum regulates slow wave currents and pacemaker activity of interstitial cells of Cajal

    Science.gov (United States)

    Zhu, Mei Hong; Sung, Tae Sik; O'Driscoll, Kate; Koh, Sang Don

    2015-01-01

    Interstitial cells of Cajal (ICC) provide pacemaker activity in gastrointestinal muscles that underlies segmental and peristaltic contractions. ICC generate electrical slow waves that are due to large-amplitude inward currents resulting from anoctamin 1 (ANO1) channels, which are Ca2+-activated Cl− channels. We investigated the hypothesis that the Ca2+ responsible for the stochastic activation of ANO1 channels during spontaneous transient inward currents (STICs) and synchronized activation of ANO1 channels during slow wave currents comes from intracellular Ca2+ stores. ICC, obtained from the small intestine of Kit+/copGFP mice, were studied under voltage and current clamp to determine the effects of blocking Ca2+ uptake into stores and release of Ca2+ via inositol 1,4,5-trisphosphate (IP3)-dependent and ryanodine-sensitive channels. Cyclocpiazonic acid, thapsigargin, 2-APB, and xestospongin C inhibited STICs and slow wave currents. Ryanodine and tetracaine also inhibited STICs and slow wave currents. Store-active compounds had no direct effects on ANO1 channels expressed in human embryonic kidney-293 cells. Under current clamp, store-active drugs caused significant depolarization of ICC and reduced spontaneous transient depolarizations (STDs). After block of ryanodine receptors with ryanodine and tetracaine, repolarization did not restore STDs. ANO1 expressed in ICC has limited access to cytoplasmic Ca2+ concentration, suggesting that pacemaker activity depends on Ca2+ dynamics in restricted microdomains. Our data from studies of isolated ICC differ somewhat from studies on intact muscles and suggest that release of Ca2+ from both IP3 and ryanodine receptors is important in generating pacemaker activity in ICC. PMID:25631870

  18. Hybrid metal-dielectric, slow wave structure with magnetic coupling and compensation

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A.V., E-mail: asmirnov@radiabeam.com [RadiaBeam Systems LLC, 1713 Stewart St., Santa Monica, CA 90404 (United States); Savin, E. [RadiaBeam Systems LLC, 1713 Stewart St., Santa Monica, CA 90404 (United States); National Research Nuclear University “MEPhI”, Moscow 115409 (Russian Federation)

    2016-06-01

    A number of electron beam vacuum devices such as small radiofrequency (RF) linear accelerators (linacs) and microwave traveling wave tubes (TWTs) utilize slow wave structures which are usually rather complicated in production and may require multi-step brazing and time consuming tuning. Fabrication of these devices becomes challenging at centimeter wavelengths, at large number of cells, and when a series or mass production of such structures is required. A hybrid, metal-dielectric, periodic structure for low gradient, low beam current applications is introduced here as a modification of Andreev’s disk-and-washer (DaW) structure. Compensated type of coupling between even and odd TE01 modes in the novel structure results in negative group velocity with absolute values as high as 0.1c–0.2c demonstrated in simulations. Sensitivity to material imperfections and electrodynamic parameters of the disk-and-ring (DaR) structure are considered numerically using a single cell model.

  19. EVIDENCE OF THERMAL CONDUCTION SUPPRESSION IN A SOLAR FLARING LOOP BY CORONAL SEISMOLOGY OF SLOW-MODE WAVES

    International Nuclear Information System (INIS)

    Wang, Tongjiang; Ofman, Leon; Provornikova, Elena; Sun, Xudong; Davila, Joseph M.

    2015-01-01

    Analysis of a longitudinal wave event observed by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory is presented. A time sequence of 131 Å images reveals that a C-class flare occurred at one footpoint of a large loop and triggered an intensity disturbance (enhancement) propagating along it. The spatial features and temporal evolution suggest that a fundamental standing slow-mode wave could be set up quickly after meeting of two initial disturbances from the opposite footpoints. The oscillations have a period of ∼12 minutes and a decay time of ∼9 minutes. The measured phase speed of 500 ± 50 km s −1 matches the sound speed in the heated loop of ∼10 MK, confirming that the observed waves are of slow mode. We derive the time-dependent temperature and electron density wave signals from six AIA extreme-ultraviolet channels, and find that they are nearly in phase. The measured polytropic index from the temperature and density perturbations is 1.64 ± 0.08 close to the adiabatic index of 5/3 for an ideal monatomic gas. The interpretation based on a 1D linear MHD model suggests that the thermal conductivity is suppressed by at least a factor of 3 in the hot flare loop at 9 MK and above. The viscosity coefficient is determined by coronal seismology from the observed wave when only considering the compressive viscosity dissipation. We find that to interpret the rapid wave damping, the classical compressive viscosity coefficient needs to be enhanced by a factor of 15 as the upper limit

  20. Experimental study on slow flexural waves around the defect modes in a phononic crystal beam using fiber Bragg gratings

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Kuo-Chih, E-mail: chuangkc@zju.edu.cn; Zhang, Zhi-Qiang; Wang, Hua-Xin

    2016-12-09

    Highlights: • Slow waves around the defect modes in a phononic crystal beam are validated. • A fiber Bragg grating displacement sensing system can measure the defect mode. • The defect mode is analyzed by a transfer matrix method with a supercell technique. - Abstract: This work experimentally studies influences of the point defect modes on the group velocity of flexural waves in a phononic crystal Timoshenko beam. Using the transfer matrix method with a supercell technique, the band structures and the group velocities around the defect modes are theoretically obtained. Particularly, to demonstrate the existence of the localized defect modes inside the band gaps, a high-sensitivity fiber Bragg grating sensing system is set up and the displacement transmittance is measured. Slow propagation of flexural waves via defect coupling in the phononic crystal beam is then experimentally demonstrated with Hanning windowed tone burst excitations.

  1. Landau-Kleffner Syndrome, Electrical Status Epilepticus in Slow Wave Sleep, and Language Regression in Children

    Science.gov (United States)

    McVicar, Kathryn A.; Shinnar, Shlomo

    2004-01-01

    The Landau-Kleffner syndrome (LKS) and electrical status epilepticus in slow wave sleep (ESES) are rare childhood-onset epileptic encephalopathies in which loss of language skills occurs in the context of an epileptiform EEG activated in sleep. Although in LKS the loss of function is limited to language, in ESES there is a wider spectrum of…

  2. Synthetic spectral analysis of a kinetic model for slow-magnetosonic waves in solar corona

    Energy Technology Data Exchange (ETDEWEB)

    Ruan, Wenzhi; He, Jiansen; Tu, Chuanyi; Wang, Linghua [School of Earth and Space Sciences, Peking University, Beijing, 100871, China, E-mail: jshept@gmail.com (China); Zhang, Lei [State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190 (China); Vocks, Christian [Leibniz-Institut für Astrophysik Potsdam, 14482, Potsdam (Germany); Marsch, Eckart [Institute for Experimental and Applied Physics, Christian-Albrechts-Universität zu Kiel, 24118 Kiel (Germany); Peter, Hardi [Max Plank Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen (Germany)

    2016-03-25

    We propose a kinetic model of slow-magnetosonic waves to explain various observational features associated with the propagating intensity disturbances (PIDs) occurring in the solar corona. The characteristics of slow mode waves, e.g, inphase oscillations of density, velocity, and thermal speed, are reproduced in this kinetic model. Moreover, the red-blue (R-B) asymmetry of the velocity distribution as self-consistently generated in the model is found to be contributed from the beam component, as a result of the competition between Landau resonance and Coulomb collisions. Furthermore, we synthesize the spectral lines and make the spectral analysis, based on the kinetic simulation data of the flux tube plasmas and the hypothesis of the surrounding background plasmas. It is found that the fluctuations of parameters of the synthetic spectral lines are basically consistent with the observations: (1) the line intensity, Doppler shift, and line width are fluctuating in phase; (2) the R-B asymmetry usually oscillate out of phase with the former three parameters; (3) the blueward asymmetry is more evident than the redward asymmetry in the R-B fluctuations. The oscillations of line parameters become weakened for the case with denser surrounding background plasmas. Similar to the observations, there is no doubled-frequency oscillation of the line width for the case with flux-tube plasmas flowing bulkly upward among the static background plasmas. Therefore, we suggest that the “wave + beam flow” kinetic model may be a viable interpretation for the PIDs observed in the solar corona.

  3. Slow-transit Constipation.

    Science.gov (United States)

    Bharucha, Adil E.; Philips, Sidney F.

    2001-08-01

    Idiopathic slow-transit constipation is a clinical syndrome predominantly affecting women, characterized by intractable constipation and delayed colonic transit. This syndrome is attributed to disordered colonic motor function. The disorder spans a spectrum of variable severity, ranging from patients who have relatively mild delays in transit but are otherwise indistinguishable from irritable bowel syndrome to patients with colonic inertia or chronic megacolon. The diagnosis is made after excluding colonic obstruction, metabolic disorders (hypothyroidism, hypercalcemia), drug-induced constipation, and pelvic floor dysfunction (as discussed by Wald ). Most patients are treated with one or more pharmacologic agents, including dietary fiber supplementation, saline laxatives (milk of magnesia), osmotic agents (lactulose, sorbitol, and polyethylene glycol 3350), and stimulant laxatives (bisacodyl and glycerol). A subtotal colectomy is effective and occasionally is indicated for patients with medically refractory, severe slow-transit constipation, provided pelvic floor dysfunction has been excluded or treated.

  4. Characterization of sleep need dissipation using EEG based slow-wave activity analysis in two age groups

    NARCIS (Netherlands)

    Garcia-Molina, G.; Baehr, K.; Steele, B.; Tsoneva, T.K.; Pfundtner, S.; Mahadevan, A.; Papas, N.; Riedner, B.; Tononi, G.; White, D.

    2017-01-01

    Introduction: In the two-process model of sleep regulation, slow-wave activity (SWA, EEG power in the 0.5–4 Hz band) is a direct indicator of sleep need. SWA builds up during NREM sleep, declines before the onset of REM sleep, remains low during REM and the level of increase in successive NREM

  5. Cued memory reactivation during slow-wave sleep promotes explicit knowledge of a motor sequence.

    Science.gov (United States)

    Cousins, James N; El-Deredy, Wael; Parkes, Laura M; Hennies, Nora; Lewis, Penelope A

    2014-11-26

    Memories are gradually consolidated after initial encoding, and this can sometimes lead to a transition from implicit to explicit knowledge. The exact physiological processes underlying this reorganization remain unclear. Here, we used a serial reaction time task to determine whether targeted memory reactivation (TMR) of specific memory traces during slow-wave sleep promotes the emergence of explicit knowledge. Human participants learned two 12-item sequences of button presses (A and B). These differed in both cue order and in the auditory tones associated with each of the four fingers (one sequence had four higher-pitched tones). Subsequent overnight sleep was monitored, and the tones associated with one learned sequence were replayed during slow-wave sleep. After waking, participants demonstrated greater explicit knowledge (p = 0.005) and more improved procedural skill (p = 0.04) for the cued sequence relative to the uncued sequence. Furthermore, fast spindles (13.5-15 Hz) at task-related motor regions predicted overnight enhancement in procedural skill (r = 0.71, p = 0.01). Auditory cues had no effect on post-sleep memory performance in a control group who received TMR before sleep. These findings suggest that TMR during sleep can alter memory representations and promote the emergence of explicit knowledge, supporting the notion that reactivation during sleep is a key mechanism in this process. Copyright © 2014 Cousins et al.

  6. Ibuprofen slows migration and inhibits bowel colonization by enteric nervous system precursors in zebrafish, chick and mouse

    Science.gov (United States)

    Schill, Ellen Merrick; Lake, Jonathan I.; Tusheva, Olga A.; Nagy, Nandor; Bery, Saya K.; Foster, Lynne; Avetisyan, Marina; Johnson, Stephen L.; Stenson, William F.; Goldstein, Allan M.; Heuckeroth, Robert O.

    2016-01-01

    Hirschsprung Disease (HSCR) is a potentially deadly birth defect characterized by the absence of the enteric nervous system (ENS) in distal bowel. Although HSCR has clear genetic causes, no HSCR-associated mutation is 100% penetrant, suggesting gene-gene and gene-environment interactions determine HSCR occurrence. To test the hypothesis that certain medicines might alter HSCR risk we treated zebrafish with medications commonly used during early human pregnancy and discovered that ibuprofen caused HSCR-like absence of enteric neurons in distal bowel. Using fetal CF-1 mouse gut slice cultures, we found that ibuprofen treated enteric neural crest-derived cells (ENCDC) had reduced migration, fewer lamellipodia and lower levels of active RAC1/CDC42. Additionally, inhibiting ROCK, a RHOA effector and known RAC1 antagonist, reversed ibuprofen effects on migrating mouse ENCDC in culture. Ibuprofen also inhibited colonization of Ret+/− mouse bowel by ENCDC in vivo and dramatically reduced bowel colonization by chick ENCDC in culture. Interestingly, ibuprofen did not affect ENCDC migration until after at least three hours of exposure. Furthermore, mice deficient in Ptgs1 (COX 1) and Ptgs2 (COX 2) had normal bowel colonization by ENCDC and normal ENCDC migration in vitro suggesting COX-independent effects. Consistent with selective and strain specific effects on ENCDC, ibuprofen did not affect migration of gut mesenchymal cells, NIH3T3, or WT C57BL/6 ENCDC, and did not affect dorsal root ganglion cell precursor migration in zebrafish. Thus, ibuprofen inhibits ENCDC migration in vitro and bowel colonization by ENCDC in vivo in zebrafish, mouse and chick, but there are cell type and strain specific responses. These data raise concern that ibuprofen may increase Hirschsprung disease risk in some genetically susceptible children. PMID:26586201

  7. Drosophila wing imaginal discs respond to mechanical injury via slow InsP3R-mediated intercellular calcium waves

    Science.gov (United States)

    Restrepo, Simon; Basler, Konrad

    2016-08-01

    Calcium signalling is a highly versatile cellular communication system that modulates basic functions such as cell contractility, essential steps of animal development such as fertilization and higher-order processes such as memory. We probed the function of calcium signalling in Drosophila wing imaginal discs through a combination of ex vivo and in vivo imaging and genetic analysis. Here we discover that wing discs display slow, long-range intercellular calcium waves (ICWs) when mechanically stressed in vivo or cultured ex vivo. These slow imaginal disc intercellular calcium waves (SIDICs) are mediated by the inositol-3-phosphate receptor, the endoplasmic reticulum (ER) calcium pump SERCA and the key gap junction component Inx2. The knockdown of genes required for SIDIC formation and propagation negatively affects wing disc recovery after mechanical injury. Our results reveal a role for ICWs in wing disc homoeostasis and highlight the utility of the wing disc as a model for calcium signalling studies.

  8. Centrally located GLP-1 receptors modulate gastric slow waves and cardiovascular function in ferrets consistent with the induction of nausea.

    Science.gov (United States)

    Lu, Zengbing; Yeung, Chi-Kong; Lin, Ge; Yew, David T W; Andrews, P L R; Rudd, John A

    2017-10-01

    Glucagon-like peptide-1 (GLP-1) receptor agonists are indicated for the treatment of Type 2 diabetes and obesity, but can cause nausea and emesis in some patients. GLP-1 receptors are distributed widely in the brain, where they contribute to mechanisms of emesis, reduced appetite and aversion, but it is not known if these centrally located receptors also contribute to a modulation of gastric slow wave activity, which is linked causally to nausea. Our aim was to investigate the potential of the GLP-1 receptor agonist, exendin-4, administered into the 3rd ventricle to modulate emesis, feeding and gastric slow wave activity. Thermoregulation and cardiovascular parameters were also monitored, as they are disturbed during nausea. Ferrets were used as common laboratory rodents do not have an emetic reflex. A guide cannula was implanted into the 3rd ventricle for delivering a previously established dose of exendin-4 (10nmol), which had been shown to induce emesis and behaviours indicative of 'nausea'. Radiotelemetry recorded gastric myoelectric activity (GMA; slow waves), blood pressure and heart rate variability (HRV), and core temperature; food intake and behaviour were also assessed. Exendin-4 (10nmol, i.c.v.) decreased the dominant frequency of GMA, with an associated increase in the percentage of bradygastric power (lasting ~4h). Food intake was inhibited in all animals, with 63% exhibiting emesis. Exendin-4 also increased blood pressure (lasting ~24h) and heart rate (lasting ~7h), decreased HRV (lasting ~24h), and caused transient hyperthermia. None of the above parameters were emesis-dependent. The present study shows for the first time that gastric slow waves may be modulated by GLP-1 receptors in the brain through mechanisms that appear independent from emesis. Taken together with a reduction in HRV, the findings are consistent with changes associated with the occurrence of nausea in humans. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Development of slow and fast wave coupling and heating from the C-Stellarator to NSTX

    Directory of Open Access Journals (Sweden)

    Hosea Joel

    2017-01-01

    Full Text Available A historical perspective on key discoveries which contributed to understanding the properties of coupling both slow and fast waves and the effects on plasma heating and current drive will be presented. Important steps made include the demonstration that the Alfven resonance was in fact a mode conversion on the C-stellarator, that toroidal m = -1 eigenmodes were excited in toroidal geometry and impurity influx caused the Z mode on the ST tokamak, that the H minority regime provided strong heating and that 3He minority could be used as well on PLT, that the 2nd harmonic majority tritium regime was viable on TFTR, and that high harmonic fast wave heating was efficient when the SOL losses were avoided on NSTX.

  10. High quality broadband spatial reflections of slow Rayleigh surface acoustic waves modulated by a graded grooved surface

    KAUST Repository

    Xu, Yanlong

    2015-01-21

    We report high quality broadband spatial reflections of Rayleigh surface acoustic waves (SAWs) through a graded grooved surface. High quality means that no wave is allowed to transmit and the incident wave is nearly all reflected to the input side. The graded grooved surface is structured by drilling one dimensional array of graded grooves with increased depths on a flat surface. We investigate SAW dispersion relations, wave field distribution at several typical SAW wavelengths, and time evolution of a Gaussian pulse through the graded grooved surface. Results show that the input broadband Rayleigh SAWs can be slowed, spatially enhanced and stopped, and finally reflected to the input side. The study suggests that engraving the flat surface can be used as an efficient and economical way to manipulate Rayleigh SAWs, which has potential application in novel SAW devices such as filters, reflectors, sensors, energy harvesters, and diodes.

  11. Nonlinear Gain Saturation in Active Slow Light Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2013-01-01

    We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated.......We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated....

  12. A tapered multi-gap multi-aperture pseudospark-sourced electron gun based X-band slow wave oscillator

    Science.gov (United States)

    Kumar, N.; Lamba, R. P.; Hossain, A. M.; Pal, U. N.; Phelps, A. D. R.; Prakash, R.

    2017-11-01

    The experimental study of a tapered, multi-gap, multi-aperture pseudospark-sourced electron gun based X-band plasma assisted slow wave oscillator is presented. The designed electron gun is based on the pseudospark discharge concept and has been used to generate a high current density and high energy electron beam simultaneously. The distribution of apertures has been arranged such that the field penetration potency inside the backspace of the hollow-cathode is different while passing through the tapered gap region. This leads to non-concurrent ignition of the discharge through all the channels which is, in general, quite challenging in the case of multi-aperture plasma cathode electron gun geometries. Multiple and successive hollow cathode phases are reported from this electron gun geometry, which have been confirmed using simulations. This geometry also has led to the achievement of ˜71% fill factor inside the slow wave oscillator for an electron beam of energy of 20 keV and a beam current density in the range of 115-190 A/cm2 at a working argon gas pressure of 18 Pa. The oscillator has generated broadband microwave output in the frequency range of 10-11.7 GHz with a peak power of ˜10 kW for ˜50 ns.

  13. Research of dynamical Characteristics of slow deformation Waves as Massif Responses on Explosions

    Science.gov (United States)

    Hachay, Olga; Khachay, Oleg; Shipeev, Oleg

    2013-04-01

    The research of massif state with use of approaches of open system theory [1-3] was developed for investigation the criterions of dissipation regimes for real rock massifs, which are under heavy man-caused influence. For realization of that research we used the data of seismic catalogue of Tashtagol mine. As a result of the analyze of that data we defined character morphology of phase trajectories of massif response, which was locally in time in a stable state: on the phase plane with coordinates released by the massif during the dynamic event energy E and lg(dE/dt) there is a local area as a ball of twisted trajectories and some not great bursts from that ball, which are not greater than 105 joules. In some time intervals that burst can be larger, than 105 joules, achieving 106 joules and yet 109 joules. [3]. Evidently there are two reciprocal depend processes: the energy accumulation in the attracted phase trajectories area and resonance fault of the accumulated energy. But after the fault the system returns again to the same attracted phase trajectories area. For analyzing of the thin structure of the chaotic area we decided to add the method of processing of the seismic monitoring data by new parameters. We shall consider each point of explosion as a source of seismic or deformation waves. Using the kinematic approach of seismic information processing we shall each point of the massif response use as a time point of the first arrival of the deformation wave for calculation of the wave velocity, because additionally we know the coordinates of the fixed response and the coordinates of explosion. The use of additional parameter-velocity of slow deformation wave propagation allowed us with use method of phase diagrams identify their hierarchic structure, which allow us to use that information for modeling and interpretation the propagation seismic and deformation waves in hierarchic structures. It is researched with use of that suggested processing method the thin

  14. Transcranial direct current stimulation in refractory continuous spikes and waves during slow sleep: a controlled study

    DEFF Research Database (Denmark)

    Varga, Edina T; Terney, Daniella; Atkins, Mary D

    2011-01-01

    Cathodal transcranial direct current stimulation (tDCS) decreases cortical excitability. The purpose of the study was to investigate whether cathodal tDCS could interrupt the continuous epileptiform activity. Five patients with focal, refractory continuous spikes and waves during slow sleep were...... recruited. Cathodal tDCS and sham stimulation were applied to the epileptic focus, before sleep (1 mA; 20 min). Cathodal tDCS did not reduce the spike-index in any of the patients....

  15. Eye Movement Desensitization and Reprocessing and Slow Wave Sleep: A Putative Mechanism of Action.

    Science.gov (United States)

    Pagani, Marco; Amann, Benedikt L; Landin-Romero, Ramon; Carletto, Sara

    2017-01-01

    Eye Movement Desensitization and Reprocessing (EMDR) is considered highly efficacious for the treatment of Post-traumatic Stress Disorder and has proved to be a valid treatment approach with a wide range of applications. However, EMDR's mechanisms of action is not yet fully understood. This is an active area of clinical and neurophysiological research, and several different hypotheses have been proposed. This paper discusses a conjecture which focuses on the similarity between the delta waves recorded by electroencephalography during Slow Wave Sleep (SWS) and those registered upon typical EMDR bilateral stimulation (eye movements or alternate tapping) during recurrent distressing memories of an emotionally traumatic event. SWS appears to have a key role in memory consolidation and in the reorganization of distant functional networks, as well as Eye Movements seem to reduce traumatic episodic memory and favor the reconsolidation of new associated information. The SWS hypothesis may put forward an explanation of how EMDR works, and is discussed also in light of other theories and neurobiological findings.

  16. Nonlinear dynamical triggering of slow slip

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Paul A [Los Alamos National Laboratory; Knuth, Matthew W [WISCONSIN; Kaproth, Bryan M [PENN STATE; Carpenter, Brett [PENN STATE; Guyer, Robert A [Los Alamos National Laboratory; Le Bas, Pierre - Yves [Los Alamos National Laboratory; Daub, Eric G [Los Alamos National Laboratory; Marone, Chris [PENN STATE

    2010-12-10

    Among the most fascinating, recent discoveries in seismology have been the phenomena of triggered slip, including triggered earthquakes and triggered-tremor, as well as triggered slow, silent-slip during which no seismic energy is radiated. Because fault nucleation depths cannot be probed directly, the physical regimes in which these phenomena occur are poorly understood. Thus determining physical properties that control diverse types of triggered fault sliding and what frictional constitutive laws govern triggered faulting variability is challenging. We are characterizing the physical controls of triggered faulting with the goal of developing constitutive relations by conducting laboratory and numerical modeling experiments in sheared granular media at varying load conditions. In order to simulate granular fault zone gouge in the laboratory, glass beads are sheared in a double-direct configuration under constant normal stress, while subject to transient perturbation by acoustic waves. We find that triggered, slow, silent-slip occurs at very small confining loads ({approx}1-3 MPa) that are smaller than those where dynamic earthquake triggering takes place (4-7 MPa), and that triggered slow-slip is associated with bursts of LFE-like acoustic emission. Experimental evidence suggests that the nonlinear dynamical response of the gouge material induced by dynamic waves may be responsible for the triggered slip behavior: the slip-duration, stress-drop and along-strike slip displacement are proportional to the triggering wave amplitude. Further, we observe a shear-modulus decrease corresponding to dynamic-wave triggering relative to the shear modulus of stick-slips. Modulus decrease in response to dynamical wave amplitudes of roughly a microstrain and above is a hallmark of elastic nonlinear behavior. We believe that the dynamical waves increase the material non-affine elastic deformation during shearing, simultaneously leading to instability and slow-slip. The inferred

  17. Reduction of nocturnal slow-wave activity affects daytime vigilance lapses and memory encoding but not reaction time or implicit learning

    NARCIS (Netherlands)

    van der Werf, Y.D.; Altena, E.; Vis, J.C.; Koene, T.; van Someren, E.J.W.

    2011-01-01

    Total sleep deprivation in healthy subjects has a profound effect on the performance on tasks measuring sustained attention or vigilance. We here report how a selective disruption of deep sleep only, that is, selective slow-wave activity (SWA) reduction, affects the performance of healthy

  18. Evaluation of QT and P wave dispersion and mean platelet volume among inflammatory bowel disease patients.

    Science.gov (United States)

    Dogan, Yuksel; Soylu, Aliye; Eren, Gulay A; Poturoglu, Sule; Dolapcioglu, Can; Sonmez, Kenan; Duman, Habibe; Sevindir, Isa

    2011-01-01

    In inflammatory bowel disease (IBD) number of thromboembolic events are increased due to hypercoagulupathy and platelet activation. Increases in mean platelet volume (MPV) can lead to platelet activation, this leads to thromboembolic events and can cause acute coronary syndromes. In IBD patients, QT-dispersion and P-wave dispersion are predictors of ventricular arrhythmias and atrial fibrilation; MPV is accepted as a risk factor for acute coronary syndromes, we aimed at evaluating the correlations of these with the duration of disease, its localization and activity. The study group consisted of 69 IBD (Ulcerative colitis n: 54, Crohn's Disease n: 15) patients and the control group included 38 healthy individuals. Disease activity was evaluated both endoscopically and clinically. Patients with existing cardiac conditions, those using QT prolonging medications and having systemic diseases, anemia and electrolyte imbalances were excluded from the study. QT-dispersion, P-wave dispersion and MPV values of both groups were compared with disease activity, its localization, duration of disease and the antibiotics used. The P-wave dispersion values of the study group were significantly higher than those of the control group. Duration of the disease was not associated with QT-dispersion, and MPV levels. QT-dispersion, P-wave dispersion, MPV and platelet count levels were similar between the active and in mild ulcerative colitis patients. QT-dispersion levels were similar between IBD patients and the control group. No difference was observed between P-wave dispersion, QT-dispersion and MPV values; with regards to disease duration, disease activity, and localization in the study group (p>0.05). P-wave dispersion which is accepted as a risk factor for the development of atrial fibirilation was found to be high in our IBD patients. This demonstrates us that the risk of developing atrial fibrillation may be high in patients with IBD. No significant difference was found in the QT

  19. Calcium waves.

    Science.gov (United States)

    Jaffe, Lionel F

    2008-04-12

    Waves through living systems are best characterized by their speeds at 20 degrees C. These speeds vary from those of calcium action potentials to those of ultraslow ones which move at 1-10 and/or 10-20 nm s(-1). All such waves are known or inferred to be calcium waves. The two classes of calcium waves which include ones with important morphogenetic effects are slow waves that move at 0.2-2 microm s(-1) and ultraslow ones. Both may be propagated by cycles in which the entry of calcium through the plasma membrane induces subsurface contraction. This contraction opens nearby stretch-sensitive calcium channels. Calcium entry through these channels propagates the calcium wave. Many slow waves are seen as waves of indentation. Some are considered to act via cellular peristalsis; for example, those which seem to drive the germ plasm to the vegetal pole of the Xenopus egg. Other good examples of morphogenetic slow waves are ones through fertilizing maize eggs, through developing barnacle eggs and through axolotl embryos during neural induction. Good examples of ultraslow morphogenetic waves are ones during inversion in developing Volvox embryos and across developing Drosophila eye discs. Morphogenetic waves may be best pursued by imaging their calcium with aequorins.

  20. The role of sleep spindles and slow-wave activity in integrating new information in semantic memory.

    Science.gov (United States)

    Tamminen, Jakke; Lambon Ralph, Matthew A; Lewis, Penelope A

    2013-09-25

    Assimilating new information into existing knowledge is a fundamental part of consolidating new memories and allowing them to guide behavior optimally and is vital for conceptual knowledge (semantic memory), which is accrued over many years. Sleep is important for memory consolidation, but its impact upon assimilation of new information into existing semantic knowledge has received minimal examination. Here, we examined the integration process by training human participants on novel words with meanings that fell into densely or sparsely populated areas of semantic memory in two separate sessions. Overnight sleep was polysomnographically monitored after each training session and recall was tested immediately after training, after a night of sleep, and 1 week later. Results showed that participants learned equal numbers of both word types, thus equating amount and difficulty of learning across the conditions. Measures of word recognition speed showed a disadvantage for novel words in dense semantic neighborhoods, presumably due to interference from many semantically related concepts, suggesting that the novel words had been successfully integrated into semantic memory. Most critically, semantic neighborhood density influenced sleep architecture, with participants exhibiting more sleep spindles and slow-wave activity after learning the sparse compared with the dense neighborhood words. These findings provide the first evidence that spindles and slow-wave activity mediate integration of new information into existing semantic networks.

  1. Why Does Sleep Slow-Wave Activity Increase After Extended Wake? Assessing the Effects of Increased Cortical Firing During Wake and Sleep.

    Science.gov (United States)

    Rodriguez, Alexander V; Funk, Chadd M; Vyazovskiy, Vladyslav V; Nir, Yuval; Tononi, Giulio; Cirelli, Chiara

    2016-12-07

    During non-rapid eye movement (NREM) sleep, cortical neurons alternate between ON periods of firing and OFF periods of silence. This bi-stability, which is largely synchronous across neurons, is reflected in the EEG as slow waves. Slow-wave activity (SWA) increases with wake duration and declines homeostatically during sleep, but the underlying mechanisms remain unclear. One possibility is neuronal "fatigue": high, sustained firing in wake would force neurons to recover with more frequent and longer OFF periods during sleep. Another possibility is net synaptic potentiation during wake: stronger coupling among neurons would lead to greater synchrony and therefore higher SWA. Here, we obtained a comparable increase in sustained firing (6 h) in cortex by: (1) keeping mice awake by exposure to novel objects to promote plasticity and (2) optogenetically activating a local population of cortical neurons at wake-like levels during sleep. Sleep after extended wake led to increased SWA, higher synchrony, and more time spent OFF, with a positive correlation between SWA, synchrony, and OFF periods. Moreover, time spent OFF was correlated with cortical firing during prior wake. After local optogenetic stimulation, SWA and cortical synchrony decreased locally, time spent OFF did not change, and local SWA was not correlated with either measure. Moreover, laser-induced cortical firing was not correlated with time spent OFF afterward. Overall, these results suggest that high sustained firing per se may not be the primary determinant of SWA increases observed after extended wake. A long-standing hypothesis is that neurons fire less during slow-wave sleep to recover from the "fatigue" accrued during wake, when overall synaptic activity is higher than in sleep. This idea, however, has rarely been tested and other factors, namely increased cortical synchrony, could explain why sleep slow-wave activity (SWA) is higher after extended wake. We forced neurons in the mouse cortex to fire

  2. Chaotic behavior in a relativistic electron beam interacting with a transverse slow electromagnetic wave

    International Nuclear Information System (INIS)

    Serbeto, A.; Alves, M.V.

    1993-01-01

    Using a nonlinear set of equations which describes the excitation of a purely transverse slow electromagnetic wave by a relativistic electron beam, it is shown that the system runs from chaotic behavior to a regular stable state due to crisis phenomenon and from stabilized soliton and repeated stabilized explosive solutions to a temporal chaos. These behaviors suggest that the primary mechanism for the saturation of the explosive instability is not only the cubic nonlinear frequency shift as pointed out by many authors until now. The inclusion of the velocity perturbation in the beam charge initial equilibrium state leads the system to these strange behaviors. (author)

  3. Eye Movement Desensitization and Reprocessing and Slow Wave Sleep: A Putative Mechanism of Action

    Directory of Open Access Journals (Sweden)

    Marco Pagani

    2017-11-01

    Full Text Available Eye Movement Desensitization and Reprocessing (EMDR is considered highly efficacious for the treatment of Post-traumatic Stress Disorder and has proved to be a valid treatment approach with a wide range of applications. However, EMDR’s mechanisms of action is not yet fully understood. This is an active area of clinical and neurophysiological research, and several different hypotheses have been proposed. This paper discusses a conjecture which focuses on the similarity between the delta waves recorded by electroencephalography during Slow Wave Sleep (SWS and those registered upon typical EMDR bilateral stimulation (eye movements or alternate tapping during recurrent distressing memories of an emotionally traumatic event. SWS appears to have a key role in memory consolidation and in the reorganization of distant functional networks, as well as Eye Movements seem to reduce traumatic episodic memory and favor the reconsolidation of new associated information. The SWS hypothesis may put forward an explanation of how EMDR works, and is discussed also in light of other theories and neurobiological findings.

  4. Resonant magnetohydrodynamic waves in high-beta plasmas

    International Nuclear Information System (INIS)

    Ruderman, M. S.

    2009-01-01

    When a global magnetohydrodynamic (MHD) wave propagates in a weakly dissipative inhomogeneous plasma, the resonant interaction of this wave with either local Alfven or slow MHD waves is possible. This interaction occurs at the resonant position where the phase velocity of the global wave coincides with the phase velocity of either Alfven or slow MHD waves. As a result of this interaction a dissipative layer embracing the resonant position is formed, its thickness being proportional to R -1/3 , where R>>1 is the Reynolds number. The wave motion in the resonant layer is characterized by large amplitudes and large gradients. The presence of large gradients causes strong dissipation of the global wave even in very weakly dissipative plasmas. Very often the global wave motion is characterized by the presence of both Alfven and slow resonances. In plasmas with small or moderate plasma beta β, the resonance positions corresponding to the Alfven and slow resonances are well separated, so that the wave motion in the Alfven and slow dissipative layers embracing the Alfven and slow resonant positions, respectively, can be studied separately. However, when β > or approx. R 1/3 , the two resonance positions are so close that the two dissipative layers overlap. In this case, instead of two dissipative layers, there is one mixed Alfven-slow dissipative layer. In this paper the wave motion in such a mixed dissipative layer is studied. It is shown that this motion is a linear superposition of two motions, one corresponding to the Alfven and the other to the slow dissipative layer. The jump of normal velocity across the mixed dissipative layer related to the energy dissipation rate is equal to the sum of two jumps, one that occurs across the Alfven dissipative layer and the other across the slow dissipative layer.

  5. Pierce-type dispersion relation for an intense relativistic electron beam interacting with a slow-wave structure

    International Nuclear Information System (INIS)

    Chen, C.

    1994-01-01

    A Pierce-type dispersion relation is derived for the interaction of an intense relativistic electron beam with a cylindrical slow-wave structure of arbitrary corrugation depth. It is shown that near a resonance, the Pierce parameter can be expressed in terms of the vacuum dispersion function and the beam current. The dispersion relation is valid in both the low-current (Compton) regime and the high-current (Raman) regime. The dispersion characteristics of the interaction, such as the linear instability growth rate and bandwidth, are analyzed for both regimes

  6. Submillimeter Wave Antenna With Slow Wave Feed Line

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Krozer, Viktor; Kotiranta, Mikko

    2009-01-01

    Submillimeter wave radiation, which is also referred to as terahertz radiation, has not been extensively explored until recently due to a lack of reliable components and devices in this frequency range. Current advances in technology have made it possible to explore this portion of the electromag...

  7. Two-wave propagation in in vitro swine distal ulna

    Science.gov (United States)

    Mano, Isao; Horii, Kaoru; Matsukawa, Mami; Otani, Takahiko

    2015-07-01

    Ultrasonic transmitted waves were obtained in an in vitro swine distal ulna specimen, which mimics a human distal radius, that consists of interconnected cortical bone and cancellous bone. The transmitted waveforms appeared similar to the fast waves, slow waves, and overlapping fast and slow waves measured in the specimen after removing the surface cortical bone (only cancellous bone). In addition, the circumferential waves in the cortical bone and water did not affect the fast and slow waves. This suggests that the fast-and-slow-wave phenomenon can be observed in an in vivo human distal radius.

  8. Slow Waves in Fractures Filled with Viscous Fluid

    Energy Technology Data Exchange (ETDEWEB)

    Korneev, Valeri

    2008-01-08

    Stoneley guided waves in a fluid-filled fracture generally have larger amplitudes than other waves, and therefore, their properties need to be incorporated in more realistic models. In this study, a fracture is modeled as an infinite layer of viscous fluid bounded by two elastic half-spaces with identical parameters. For small fracture thickness, I obtain a simple dispersion equation for wave-propagation velocity. This velocity is much smaller than the velocity of a fluid wave in a Biot-type solution, in which fracture walls are assumed to be rigid. At seismic prospecting frequencies and realistic fracture thicknesses, the Stoneley guided wave has wavelengths on the order of several meters and an attenuation Q factor exceeding 10, which indicates the possibility of resonance excitation in fluid-bearing rocks. The velocity and attenuation of Stoneley guided waves are distinctly different at low frequencies for water and oil. The predominant role of fractures in fluid flow at field scales is supported by permeability data showing an increase of several orders of magnitude when compared to values obtained at laboratory scales. These data suggest that Stoneley guided waves should be taken into account in theories describing seismic wave propagation in fluid-saturated rocks.

  9. The Frequency-dependent Damping of Slow Magnetoacoustic Waves in a Sunspot Umbral Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, S. Krishna; Jess, D. B. [Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN (United Kingdom); Doorsselaere, T. Van [Centre for mathematical Plasma Astrophysics, Mathematics Department, KU Leuven, Celestijnenlaan 200B bus 2400, B-3001 Leuven (Belgium); Verth, G. [School of Mathematics and Statistics, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH (United Kingdom); Morton, R. J. [Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Ellison Building, Newcastle upon Tyne, NE1 8ST (United Kingdom); Fedun, V. [Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield, S1 3JD (United Kingdom); Erdélyi, R. [Solar Physics and Space Plasma Research Centre (SP2RC), School of Mathematics and Statistics, University of Sheffield, Sheffield S3 7RH (United Kingdom); Christian, D. J., E-mail: krishna.prasad@qub.ac.uk [Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330 (United States)

    2017-09-20

    High spatial and temporal resolution images of a sunspot, obtained simultaneously in multiple optical and UV wavelengths, are employed to study the propagation and damping characteristics of slow magnetoacoustic waves up to transition region heights. Power spectra are generated from intensity oscillations in sunspot umbra, across multiple atmospheric heights, for frequencies up to a few hundred mHz. It is observed that the power spectra display a power-law dependence over the entire frequency range, with a significant enhancement around 5.5 mHz found for the chromospheric channels. The phase difference spectra reveal a cutoff frequency near 3 mHz, up to which the oscillations are evanescent, while those with higher frequencies propagate upward. The power-law index appears to increase with atmospheric height. Also, shorter damping lengths are observed for oscillations with higher frequencies suggesting frequency-dependent damping. Using the relative amplitudes of the 5.5 mHz (3 minute) oscillations, we estimate the energy flux at different heights, which seems to decay gradually from the photosphere, in agreement with recent numerical simulations. Furthermore, a comparison of power spectra across the umbral radius highlights an enhancement of high-frequency waves near the umbral center, which does not seem to be related to magnetic field inclination angle effects.

  10. Mechanisms of Memory Retrieval in Slow-Wave Sleep

    Science.gov (United States)

    Cairney, Scott A; Sobczak, Justyna M; Lindsay, Shane

    2017-01-01

    Abstract Study Objectives Memories are strengthened during sleep. The benefits of sleep for memory can be enhanced by re-exposing the sleeping brain to auditory cues; a technique known as targeted memory reactivation (TMR). Prior studies have not assessed the nature of the retrieval mechanisms underpinning TMR: the matching process between auditory stimuli encountered during sleep and previously encoded memories. We carried out two experiments to address this issue. Methods In Experiment 1, participants associated words with verbal and nonverbal auditory stimuli before an overnight interval in which subsets of these stimuli were replayed in slow-wave sleep. We repeated this paradigm in Experiment 2 with the single difference that the gender of the verbal auditory stimuli was switched between learning and sleep. Results In Experiment 1, forgetting of cued (vs. noncued) associations was reduced by TMR with verbal and nonverbal cues to similar extents. In Experiment 2, TMR with identical nonverbal cues reduced forgetting of cued (vs. noncued) associations, replicating Experiment 1. However, TMR with nonidentical verbal cues reduced forgetting of both cued and noncued associations. Conclusions These experiments suggest that the memory effects of TMR are influenced by the acoustic overlap between stimuli delivered at training and sleep. Our findings hint at the existence of two processing routes for memory retrieval during sleep. Whereas TMR with acoustically identical cues may reactivate individual associations via simple episodic matching, TMR with nonidentical verbal cues may utilize linguistic decoding mechanisms, resulting in widespread reactivation across a broad category of memories. PMID:28934526

  11. Mechanisms of Memory Retrieval in Slow-Wave Sleep.

    Science.gov (United States)

    Cairney, Scott A; Sobczak, Justyna M; Lindsay, Shane; Gaskell, M Gareth

    2017-09-01

    Memories are strengthened during sleep. The benefits of sleep for memory can be enhanced by re-exposing the sleeping brain to auditory cues; a technique known as targeted memory reactivation (TMR). Prior studies have not assessed the nature of the retrieval mechanisms underpinning TMR: the matching process between auditory stimuli encountered during sleep and previously encoded memories. We carried out two experiments to address this issue. In Experiment 1, participants associated words with verbal and nonverbal auditory stimuli before an overnight interval in which subsets of these stimuli were replayed in slow-wave sleep. We repeated this paradigm in Experiment 2 with the single difference that the gender of the verbal auditory stimuli was switched between learning and sleep. In Experiment 1, forgetting of cued (vs. noncued) associations was reduced by TMR with verbal and nonverbal cues to similar extents. In Experiment 2, TMR with identical nonverbal cues reduced forgetting of cued (vs. noncued) associations, replicating Experiment 1. However, TMR with nonidentical verbal cues reduced forgetting of both cued and noncued associations. These experiments suggest that the memory effects of TMR are influenced by the acoustic overlap between stimuli delivered at training and sleep. Our findings hint at the existence of two processing routes for memory retrieval during sleep. Whereas TMR with acoustically identical cues may reactivate individual associations via simple episodic matching, TMR with nonidentical verbal cues may utilize linguistic decoding mechanisms, resulting in widespread reactivation across a broad category of memories. © Sleep Research Society 2017. Published by Oxford University Press [on behalf of the Sleep Research Society].

  12. Vocabulary learning benefits from REM after slow-wave sleep.

    Science.gov (United States)

    Batterink, Laura J; Westerberg, Carmen E; Paller, Ken A

    2017-10-01

    Memory reactivation during slow-wave sleep (SWS) influences the consolidation of recently acquired knowledge. This reactivation occurs spontaneously during sleep but can also be triggered by presenting learning-related cues, a technique known as targeted memory reactivation (TMR). Here we examined whether TMR can improve vocabulary learning. Participants learned the meanings of 60 novel words. Auditory cues for half the words were subsequently presented during SWS in an afternoon nap. Memory performance for cued versus uncued words did not differ at the group level but was systematically influenced by REM sleep duration. Participants who obtained relatively greater amounts of REM showed a significant benefit for cued relative to uncued words, whereas participants who obtained little or no REM demonstrated a significant effect in the opposite direction. We propose that REM after SWS may be critical for the consolidation of highly integrative memories, such as new vocabulary. Reactivation during SWS may allow newly encoded memories to be associated with other information, but this association can include disruptive linkages with pre-existing memories. Subsequent REM sleep may then be particularly beneficial for integrating new memories into appropriate pre-existing memory networks. These findings support the general proposition that memory storage benefits optimally from a cyclic succession of SWS and REM. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Quantitative Analysis of the Effects of Slow Wave Sleep Deprivation During the First 3 h of Sleep on Subsequent EEG Power Density

    NARCIS (Netherlands)

    Dijk, Derk Jan; Beersma, Domien G.M.; Daan, Serge; Bloem, Gerda M.; Hoofdakker, Rutger H. van den

    1987-01-01

    The relation between EEG power density during slow wave sleep (SWS) deprivation and power density during subsequent sleep was investigated. Nine young male adults slept in the laboratory for 3 consecutive nights. Spectral analysis of the EEG on the 2nd (baseline) night revealed an exponential

  14. On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind

    Energy Technology Data Exchange (ETDEWEB)

    Verscharen, Daniel [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Chen, Christopher H. K. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Wicks, Robert T., E-mail: daniel.verscharen@unh.edu, E-mail: christopher.chen@imperial.ac.uk, E-mail: r.wicks@ucl.ac.uk [Mullard Space Science Laboratory, University College London, London WC1E 6BT (United Kingdom)

    2017-05-10

    Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for nonthermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a nonpropagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully kinetic numerical calculations, results from two-fluid theory, and magnetohydrodynamics (MHD). This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high β . MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, which suggests that the plasma behaves more like a fluid in the solar wind than expected.

  15. On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind

    International Nuclear Information System (INIS)

    Verscharen, Daniel; Chen, Christopher H. K.; Wicks, Robert T.

    2017-01-01

    Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for nonthermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a nonpropagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully kinetic numerical calculations, results from two-fluid theory, and magnetohydrodynamics (MHD). This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high β . MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, which suggests that the plasma behaves more like a fluid in the solar wind than expected.

  16. Experimental determination of the slow-neutron wavelength distribution

    DEFF Research Database (Denmark)

    Lebech, Bente; Mikke, K.; Sledziewska-Blocka, D.

    1970-01-01

    Different experiments for determining the slow-neutron wavelength distribution in the region 227-3 meV have been carried out, and the results compared. It is concluded that the slow-neutron wave-length distribution can be determined accurately by elastic scattering on a pure incoherent or a pure...

  17. Outcomes of bowel program in spinal cord injury patients with neurogenic bowel dysfunction

    Directory of Open Access Journals (Sweden)

    Zuhal Ozisler

    2015-01-01

    Full Text Available In this study, we aimed to determine gastrointestinal problems associated with neurogenic bowel dysfunction in spinal cord injury patients and to assess the efficacy of bowel program on gastrointestinal problems and the severity of neurogenic bowel dysfunction. Fifty-five spinal cord injury patients were included in this study. A bowel program according to the characteristics of neurogenic bowel dysfunction was performed for each patient. Before and after bowel program, gastrointestinal problems (constipation, difficult intestinal evacuation, incontinence, abdominal pain, abdominal distension, loss of appetite, hemorrhoids, rectal bleeding and gastrointestinal induced autonomic dysreflexia and bowel evacuation methods (digital stimulation, oral medication, suppositories, abdominal massage, Valsalva maneuver and manual evacuation were determined. Neurogenic bowel dysfunction score was used to assess the severity of neurogenic bowel dysfunction. At least one gastrointestinal problem was identified in 44 (80% of the 55 patients before bowel program. Constipation (56%, 31/55 and incontinence (42%, 23/55 were the most common gastrointestinal problems. Digital rectal stimulation was the most common method for bowel evacuation, both before (76%, 42/55 and after (73%, 40/55 bowel program. Oral medication, enema and manual evacuation application rates were significantly decreased and constipation, difficult intestinal evacuation, abdominal distention, and abdominal pain rates were significantly reduced after bowel program. In addition, mean neurogenic bowel dysfunction score was decreased after bowel program. An effective bowel program decreases the severity of neurogenic bowel dysfunction and reduces associated gastrointestinal problems in patients with spinal cord injury.

  18. Pulsar slow-down epochs

    International Nuclear Information System (INIS)

    Heintzmann, H.; Novello, M.

    1981-01-01

    The relative importance of magnetospheric currents and low frequency waves for pulsar braking is assessed and a model is developed which tries to account for the available pulsar timing data under the unifying aspect that all pulsars have equal masses and magnetic moments and are born as rapid rotators. Four epochs of slow-down are distinguished which are dominated by different braking mechanisms. According to the model no direct relationship exists between 'slow-down age' and true age of a pulsar and leads to a pulsar birth-rate of one event per hundred years. (Author) [pt

  19. Oscillating Square Wave Transcranial Direct Current Stimulation (tDCS) Delivered During Slow Wave Sleep Does Not Improve Declarative Memory More Than Sham: A Randomized Sham Controlled Crossover Study.

    Science.gov (United States)

    Sahlem, Gregory L; Badran, Bashar W; Halford, Jonathan J; Williams, Nolan R; Korte, Jeffrey E; Leslie, Kimberly; Strachan, Martha; Breedlove, Jesse L; Runion, Jennifer; Bachman, David L; Uhde, Thomas W; Borckardt, Jeffery J; George, Mark S

    2015-01-01

    A 2006 trial in healthy medical students found that anodal slow oscillating tDCS delivered bi-frontally during slow wave sleep had an enhancing effect in declarative, but not procedural memory. Although there have been supporting animal studies, and similar findings in pathological groups, this study has not been replicated, or refuted, in the intervening years. We therefore tested these earlier results for replication using similar methods with the exception of current waveform (square in our study, nearly sinusoidal in the original). Our objective was to test the findings of a 2006 trial suggesting bi-frontal anodal tDCS during slow wave sleep enhances declarative memory. Twelve students (mean age 25, 9 women) free of medical problems underwent two testing conditions (active, sham) in a randomized counterbalanced fashion. Active stimulation consisted of oscillating square wave tDCS delivered during early Non-Rapid Eye Movement (NREM) sleep. The sham condition consisted of setting-up the tDCS device and electrodes, but not turning it on during sleep. tDCS was delivered bi-frontally with anodes placed at F3/F4, and cathodes placed at mastoids. Current density was 0.517 mA/cm(2), and oscillated between zero and maximal current at a frequency of 0.75 Hz. Stimulation occurred during five-five minute blocks with 1-min inter-block intervals (25 min total stimulation). The primary outcomes were both declarative memory consolidation measured by a paired word association test (PWA), and non-declarative memory, measured by a non-dominant finger-tapping test (FTT). We also recorded and analyzed sleep EEG. There was no difference in the number of paired word associations remembered before compared to after sleep [(active = 3.1 ± 3.0 SD more associations) (sham = 3.8 ± 3.1 SD more associations)]. Finger tapping improved, (non-significantly) following active stimulation [(3.6 ± 2.7 SD correctly typed sequences) compared to sham stimulation (2.3 ± 2.2 SD correctly typed

  20. Targeted memory reactivation during slow wave sleep facilitates emotional memory consolidation.

    Science.gov (United States)

    Cairney, Scott A; Durrant, Simon J; Hulleman, Johan; Lewis, Penelope A

    2014-04-01

    To investigate the mechanisms by which auditory targeted memory reactivation (TMR) during slow wave sleep (SWS) influences the consolidation of emotionally negative and neutral memories. Each of 72 (36 negative, 36 neutral) picture-location associations were encoded with a semantically related sound. During a subsequent nap, half of the sounds were replayed in SWS, before picture-location recall was examined in a final test. Manchester Sleep Laboratory, University of Manchester. 15 adults (3 male) mean age = 20.40 (standard deviation ± 3.07). TMR with auditory cues during SWS. Performance was assessed by memory accuracy and recall response times (RTs). Data were analyzed with a 2 (sound: replayed/not replayed) × 2 (emotion: negative/neutral) repeated measures analysis of covariance with SWS duration, and then SWS spindles, as the mean-centered covariate. Both analyses revealed a significant three-way interaction for RTs but not memory accuracy. Critically, SWS duration and SWS spindles predicted faster memory judgments for negative, relative to neutral, picture locations that were cued with TMR. TMR initiates an enhanced consolidation process during subsequent SWS, wherein sleep spindles mediate the selective enhancement of reactivated emotional memories.

  1. Theory of a slow-light catastrophe

    International Nuclear Information System (INIS)

    Leonhardt, Ulf

    2002-01-01

    In diffraction catastrophes such as the rainbow, the wave nature of light resolves ray singularities and draws delicate interference patterns. In quantum catastrophes such as the black hole, the quantum nature of light resolves wave singularities and creates characteristic quantum effects related to Hawking radiation. This paper describes the theory behind a recent proposal [U. Leonhardt, Nature (London) 415, 406 (2002)] to generate a quantum catastrophe of slow light

  2. Theory of a slow-light catastrophe

    Science.gov (United States)

    Leonhardt, Ulf

    2002-04-01

    In diffraction catastrophes such as the rainbow, the wave nature of light resolves ray singularities and draws delicate interference patterns. In quantum catastrophes such as the black hole, the quantum nature of light resolves wave singularities and creates characteristic quantum effects related to Hawking radiation. This paper describes the theory behind a recent proposal [U. Leonhardt, Nature (London) 415, 406 (2002)] to generate a quantum catastrophe of slow light.

  3. Theory of a Slow-Light Catastrophe

    OpenAIRE

    Leonhardt, Ulf

    2001-01-01

    In diffraction catastrophes such as the rainbow the wave nature of light resolves ray singularities and draws delicate interference patterns. In quantum catastrophes such as the black hole the quantum nature of light resolves wave singularities and creates characteristic quantum effects related to Hawking radiation. The paper describes the theory behind a recent proposal [U. Leonhardt, arXiv:physics/0111058, Nature (in press)] to generate a quantum catastrophe of slow light.

  4. Short bowel syndrome

    International Nuclear Information System (INIS)

    Engels, L.G.J.B.

    1983-01-01

    This thesis describes some aspects of short bowel syndrome. When approximately 1 m or less small bowel is retained after extensive resection, a condition called short bowel syndrome is present. Since the advent of parenteral nutrition, the prognosis of patients with a very short bowel has dramatically improved. Patients with 40 to 100 cm remaining jejunum and/or ileum can generally be maintained with oral nutrition due to increased absorption of the small bowel remnant as result of intestinal adaptation. This study reports clinical, biochemical and nutritional aspects of short bowel patients on oral or parenteral nutrition, emphasizing data on absorption of various nutrients and on bone metabolism. Furthermore, some technical apsects concerning long-term parenteral nutrition are discussed. (Auth.)

  5. Non-small-bowel abnormalities identified during small bowel capsule endoscopy

    NARCIS (Netherlands)

    Hoedemakers, Reinier; Westerhof, Jessie; Weersma, Rinse K.; Koornstra, Jan J.

    2014-01-01

    AIM: To investigate the incidence of non-small-bowel abnormalities in patients referred for small bowel capsule endoscopy, this single center study was performed. METHODS: Small bowel capsule endoscopy is an accepted technique to investigate obscure gastrointestinal bleeding. This is defined as

  6. Bladder, Bowel, and Sexual Dysfunction in Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Ryuji Sakakibara

    2011-01-01

    Full Text Available Bladder dysfunction (urinary urgency/frequency, bowel dysfunction (constipation, and sexual dysfunction (erectile dysfunction (also called “pelvic organ” dysfunctions are common nonmotor disorders in Parkinson's disease (PD. In contrast to motor disorders, pelvic organ autonomic dysfunctions are often nonresponsive to levodopa treatment. The brain pathology causing the bladder dysfunction (appearance of overactivity involves an altered dopamine-basal ganglia circuit, which normally suppresses the micturition reflex. By contrast, peripheral myenteric pathology causing slowed colonic transit (loss of rectal contractions and central pathology causing weak strain and paradoxical anal sphincter contraction on defecation (PSD, also called as anismus are responsible for the bowel dysfunction. In addition, hypothalamic dysfunction is mostly responsible for the sexual dysfunction (decrease in libido and erection in PD, via altered dopamine-oxytocin pathways, which normally promote libido and erection. The pathophysiology of the pelvic organ dysfunction in PD differs from that in multiple system atrophy; therefore, it might aid in differential diagnosis. Anticholinergic agents are used to treat bladder dysfunction in PD, although these drugs should be used with caution particularly in elderly patients who have cognitive decline. Dietary fibers, laxatives, and “prokinetic” drugs such as serotonergic agonists are used to treat bowel dysfunction in PD. Phosphodiesterase inhibitors are used to treat sexual dysfunction in PD. These treatments might be beneficial in maximizing the patients' quality of life.

  7. Bladder, bowel, and sexual dysfunction in Parkinson's disease.

    Science.gov (United States)

    Sakakibara, Ryuji; Kishi, Masahiko; Ogawa, Emina; Tateno, Fuyuki; Uchiyama, Tomoyuki; Yamamoto, Tatsuya; Yamanishi, Tomonori

    2011-01-01

    Bladder dysfunction (urinary urgency/frequency), bowel dysfunction (constipation), and sexual dysfunction (erectile dysfunction) (also called "pelvic organ" dysfunctions) are common nonmotor disorders in Parkinson's disease (PD). In contrast to motor disorders, pelvic organ autonomic dysfunctions are often nonresponsive to levodopa treatment. The brain pathology causing the bladder dysfunction (appearance of overactivity) involves an altered dopamine-basal ganglia circuit, which normally suppresses the micturition reflex. By contrast, peripheral myenteric pathology causing slowed colonic transit (loss of rectal contractions) and central pathology causing weak strain and paradoxical anal sphincter contraction on defecation (PSD, also called as anismus) are responsible for the bowel dysfunction. In addition, hypothalamic dysfunction is mostly responsible for the sexual dysfunction (decrease in libido and erection) in PD, via altered dopamine-oxytocin pathways, which normally promote libido and erection. The pathophysiology of the pelvic organ dysfunction in PD differs from that in multiple system atrophy; therefore, it might aid in differential diagnosis. Anticholinergic agents are used to treat bladder dysfunction in PD, although these drugs should be used with caution particularly in elderly patients who have cognitive decline. Dietary fibers, laxatives, and "prokinetic" drugs such as serotonergic agonists are used to treat bowel dysfunction in PD. Phosphodiesterase inhibitors are used to treat sexual dysfunction in PD. These treatments might be beneficial in maximizing the patients' quality of life.

  8. Slow rupture of frictional interfaces

    Science.gov (United States)

    Bar Sinai, Yohai; Brener, Efim A.; Bouchbinder, Eran

    2012-02-01

    The failure of frictional interfaces and the spatiotemporal structures that accompany it are central to a wide range of geophysical, physical and engineering systems. Recent geophysical and laboratory observations indicated that interfacial failure can be mediated by slow slip rupture phenomena which are distinct from ordinary, earthquake-like, fast rupture. These discoveries have influenced the way we think about frictional motion, yet the nature and properties of slow rupture are not completely understood. We show that slow rupture is an intrinsic and robust property of simple non-monotonic rate-and-state friction laws. It is associated with a new velocity scale cmin, determined by the friction law, below which steady state rupture cannot propagate. We further show that rupture can occur in a continuum of states, spanning a wide range of velocities from cmin to elastic wave-speeds, and predict different properties for slow rupture and ordinary fast rupture. Our results are qualitatively consistent with recent high-resolution laboratory experiments and may provide a theoretical framework for understanding slow rupture phenomena along frictional interfaces.

  9. Slow shock characteristics as a function of distance from the X-line in the magnetotail

    International Nuclear Information System (INIS)

    Lee, L.C.; Lin, Y.; Shi, Y.; Tsurutani, B.T.

    1989-01-01

    Both particle and MHD simulations are performed to study the characteristics of slow shocks in the magnetotail. The particle simulations indicate that switch-off shocks exhibit large amplitude rotational wave trains, while magnetotail slow shocks with an intermediate Mach number M An c congruent 0.98 do not display such rotational wave trains. The MHD simulations show that the spontaneous reconnection process in the near-earth plasma sheet leads to the formation of a pair of slow shocks tailward of the reconnection line (X-line). The properties of slow shocks are found to vary as a function of the distance from X-line due to the fomation of plasmoid. Slow shocks in most regions of the magnetotail are found to be non-switch-off shocks with M An <0.98. The present results are used to discuss the lack of large amplitude rotational wave trains at slow shocks in the deep magnetotail. copyright American Geophysical Union 1989

  10. Small Bowel Bleeding

    Science.gov (United States)

    ... pouchings in the wall of the colon), or cancer. Upper GI (esophagus, stomach, or duodenum) bleeding is most often due ... begins transmitting images of the inside of the esophagus, stomach, and small bowel to a ... Bowel Disease Irritable Bowel Syndrome ...

  11. Large bowel resection

    Science.gov (United States)

    ... blockage in the intestine due to scar tissue Colon cancer Diverticular disease (disease of the large bowel) Other reasons for bowel resection are: Familial polyposis (polyps are growths on the lining of the colon or rectum) Injuries that damage the large bowel ...

  12. Slow oscillations orchestrating fast oscillations and memory consolidation.

    Science.gov (United States)

    Mölle, Matthias; Born, Jan

    2011-01-01

    Slow-wave sleep (SWS) facilitates the consolidation of hippocampus-dependent declarative memory. Based on the standard two-stage memory model, we propose that memory consolidation during SWS represents a process of system consolidation which is orchestrated by the neocortical memory. The slow oscillations temporally group neuronal activity into up-states of strongly enhanced neuronal activity and down-states of neuronal silence. In a feed-forward efferent action, this grouping is induced not only in the neocortex but also in other structures relevant to consolidation, namely the thalamus generating 10-15Hz spindles, and the hippocampus generating sharp wave-ripples, with the latter well known to accompany a replay of newly encoded memories taking place in hippocampal circuitries. The feed-forward synchronizing effect of the slow oscillation enables the formation of spindle-ripple events where ripples and accompanying reactivated hippocampal memory information become nested into the single troughs of spindles. Spindle-ripple events thus enable reactivated memory-related hippocampal information to be fed back to neocortical networks in the excitable slow oscillation up-state where they can induce enduring plastic synaptic changes underlying the effective formation of long-term memories. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Traveling wave tube and method of manufacture

    Science.gov (United States)

    Vancil, Bernard K. (Inventor)

    2004-01-01

    A traveling wave tube includes a glass or other insulating envelope having a plurality of substantially parallel glass rods supported therewithin which in turn support an electron gun, a collector and an intermediate slow wave structure. The slow wave structure itself provides electrostatic focussing of a central electron beam thereby eliminating the need for focussing magnetics and materially decreasing the cost of construction as well as enabling miniaturization. The slow wave structure advantageously includes cavities along the electron beam through which the r.f. energy is propagated, or a double, interleaved ring loop structure supported by dielectric fins within a ground plane cylinder disposed coaxially within the glass envelope.

  14. The Localizing Value Of Focal Delta Slowing In Temporal Lobe ...

    African Journals Online (AJOL)

    Slow wave EEG had a higher marginal probability than neuropsychological assessment of predicting the focus, and was equally effective as other investigative methods. Conclusion These results suggest that focal temporal delta slowing is useful in the localization of epileptogenic foci. There was no discordance with the ...

  15. Increased frontal sleep slow wave activity in adolescents with major depression

    Directory of Open Access Journals (Sweden)

    Noemi Tesler

    2016-01-01

    Full Text Available Sleep slow wave activity (SWA, the major electrophysiological characteristic of deep sleep, mirrors both cortical restructuring and functioning. The incidence of Major Depressive Disorder (MDD substantially rises during the vulnerable developmental phase of adolescence, where essential cortical restructuring is taking place. The goal of this study was to assess characteristics of SWA topography in adolescents with MDD, in order to assess abnormalities in both cortical restructuring and functioning on a local level. All night high-density EEG was recorded in 15 patients meeting DSM-5 criteria for MDD and 15 sex- and age-matched healthy controls. The actual symptom severity was assessed using the Children's Depression Rating Scale—Revised (CDRS-R. Topographical power maps were calculated based on the average SWA of the first non-rapid eye movement (NREM sleep episode. Depressed adolescents exhibited significantly more SWA in a cluster of frontal electrodes compared to controls. SWA over frontal brain regions correlated positively with the CDRS-R subscore “morbid thoughts”. Self-reported sleep latency was significantly higher in depressed adolescents compared to controls whereas sleep architecture did not differ between the groups. Higher frontal SWA in depressed adolescents may represent a promising biomarker tracing cortical regions of intense use and/or restructuring.

  16. Experiments on the thermalization of slow neutrons by liquid hydrogen (1962)

    International Nuclear Information System (INIS)

    Cribier, D.; Jacrot, B.; Lacaze, A.; Roubeau, P.

    1962-01-01

    In order to increase the flux of neutrons of long wave-length (λ > 4 A) emerging from a channel in the EL-3, a liquid hydrogen device was introduced into a channel of the reactor (Channel H 1 ). The principle of the device is simple. A volume of liquid hydrogen is introduced as close as possible to the reactor core into a region of intense isotropic flux. This hydrogen slows down the slow neutrons; because of the very small mean free diffusion path of slow in hydrogen, this slowing down is considerable even in a small volume of liquid hydrogen, and the spectrum temperature of neutrons emerging from the volume of liquid hydrogen can therefore be shifted. The intensity gain for neutrons with a wave length λ, is a G (λ) function which, for perfect thermalization and ignoring capture, is expressed by: G (λ) = 225 exp (- 45.3/λ 2 ), assuming a temperature of 300 deg. K for the neutrons before cooling and is 20 deg. K after cooling. For a wave-length of 5 A, the theoretical maximum gain of thus about 37. (authors) [fr

  17. Kinetic slow mode-type solitons

    Directory of Open Access Journals (Sweden)

    K. Baumgärtel

    2005-01-01

    Full Text Available One-dimensional hybrid code simulations are presented, carried out in order both to study solitary waves of the slow mode branch in an isotropic, collisionless, medium-β plasma (βi=0.25 and to test the fluid based soliton interpretation of Cluster observed strong magnetic depressions (Stasiewicz et al., 2003; Stasiewicz, 2004 against kinetic theory. In the simulations, a variety of strongly oblique, large amplitude, solitons are seen, including solitons with Alfvenic polarization, similar to those predicted by the Hall-MHD theory, and robust, almost non-propagating, solitary structures of slow magnetosonic type with strong magnetic field depressions and perpendicular ion heating, which have no counterpart in fluid theory. The results support the soliton-based interpretation of the Cluster observations, but reveal substantial deficiencies of Hall-MHD theory in describing slow mode-type solitons in a plasma of moderate beta.

  18. A mechanism for upper airway stability during slow wave sleep.

    Science.gov (United States)

    McSharry, David G; Saboisky, Julian P; Deyoung, Pam; Matteis, Paul; Jordan, Amy S; Trinder, John; Smales, Erik; Hess, Lauren; Guo, Mengshuang; Malhotra, Atul

    2013-04-01

    The severity of obstructive sleep apnea is diminished (sometimes markedly) during slow wave sleep (SWS). We sought to understand why SWS stabilizes the upper airway. Increased single motor unit (SMU) activity of the major upper airway dilating muscle (genioglossus) should improve upper airway stability. Therefore, we hypothesized that genioglossus SMUs would increase their activity during SWS in comparison with Stage N2 sleep. The activity of genioglossus SMUs was studied on both sides of the transition between Stage N2 sleep and SWS. Sleep laboratory. Twenty-nine subjects (age 38 ± 13 yr, 17 males) were studied. SWS. Subjects slept overnight with fine-wire electrodes in their genioglossus muscles and with full polysomnographic and end tidal carbon dioxide monitors. Fifteen inspiratory phasic (IP) and 11 inspiratory tonic (IT) units were identified from seven subjects and these units exhibited significantly increased inspiratory discharge frequencies during SWS compared with Stage N2 sleep. The peak discharge frequency of the inspiratory units (IP and IT) was 22.7 ± 4.1 Hz in SWS versus 20.3 ± 4.5 Hz in Stage N2 (P sleep (82.6 ± 39.5 %TI, P sleep (12.6 ± 3.1 Hz, P = 0.035). There was minimal recruitment or derecruitment of units between SWS and Stage N2 sleep. Increased genioglossus SMU activity likely makes the airway more stable and resistant to collapse throughout the respiratory cycle during SWS.

  19. Immunoscintigraphy with 99Tc-labelled monoclonal anti granulocyte antibodies in patients with inflammatory bowel disease

    International Nuclear Information System (INIS)

    Klisarova, A.; Tranulov, G.

    1996-01-01

    Antigranulocyte immunoscintigraphy with 99 Tc-labelled monoclonal antigranolocyte antibodies (MAb BW 250/83, Granulozyt) was carried out in ten patients with symptoms of inflammatory bowel disease to exclude or confirm the presence of an inflammatory process. A slow iv infusion of 740 MBq of the antibodies was performed 40 minutes after labelling. A whole-body scan was done at hours 4 and 24 post injection. In four patients planar scintigraphy of abdominal region only was also performed for better visualization of the pathological findings. Immunoscintigraphy provided evidence of an inflammatory bowel process in 8 cases (true positive), and excluded the diagnosis in one case (true negative). There was one false negative result.The study shows that immunoscintigraphy with 99 Tc-labelled antibodies (Granulozyt) is an easily performed procedure, with high specificity for diagnosing inflammatory bowel disease and can be carried out as a routine practice in nuclear medicine. 7 refs., 1 tab., 4 figs. (author)

  20. Bowel-associated dermatosis-arthritis syndrome in an adolescent with short bowel syndrome.

    Science.gov (United States)

    Pereira, Ester; Estanqueiro, Paula; Almeida, Susana; Ferreira, Ricardo; Tellechea, Oscar; Salgado, Manuel

    2014-09-01

    Bowel-associated dermatosis-arthritis syndrome (BADAS) is a neutrophilic dermatosis, characterized by the occurrence of arthritis and skin lesions related to bowel disease with or without bowel bypass. We report an unusual case of BADAS in a 15-year-old white male with congenital aganglionosis of the colon and hypoganglionosis of the small intestine and multiple bowel surgeries in childhood complicated by short bowel syndrome. He presented with recurrent peripheral polyarthritis, tenosynovitis, and painful erythematous subcutaneous nodules located on the dorsolateral regions of the legs and on the dorsa of the feet. Histological examination disclosed a neutrophilic dermatosis confirming the diagnosis of BADAS.Although an uncommon disease, especially at pediatric age, it is important to evoke the diagnosis of BADAS in children and adolescents with bowel disease, because treatment options and prognosis are distinct from other rheumatologic conditions.

  1. Bowel Movement

    Science.gov (United States)

    A bowel movement is the last stop in the movement of food through your digestive tract. Your stool passes out of ... what you eat and drink. Sometimes a bowel movement isn't normal. Diarrhea happens when stool passes ...

  2. Elastic scattering of slow positrons by helium

    International Nuclear Information System (INIS)

    Amusia, M.Ya.; Cherepkov, N.A.; Chernysheva, L.V.; Shapiro, S.G.

    1976-01-01

    The s-, p-, d- and f-wave phaseshifts for elastic scattering of slow positrons by He are calculated using a simplified version of the random phase approximation with exchange, with virtual positronium formation effect taken into account. (author)

  3. A Flexible Multiring Concentric Electrode for Non-Invasive Identification of Intestinal Slow Waves

    Directory of Open Access Journals (Sweden)

    Victor Zena-Giménez

    2018-01-01

    Full Text Available Developing new types of optimized electrodes for specific biomedical applications can substantially improve the quality of the sensed signals. Concentric ring electrodes have been shown to provide enhanced spatial resolution to that of conventional disc electrodes. A sensor with different electrode sizes and configurations (monopolar, bipolar, etc. that provides simultaneous records would be very helpful for studying the best signal-sensing arrangement. A 5-pole electrode with an inner disc and four concentric rings of different sizes was developed and tested on surface intestinal myoelectrical recordings from healthy humans. For good adaptation to a curved body surface, the electrode was screen-printed onto a flexible polyester substrate. To facilitate clinical use, it is self-adhesive, incorporates a single connector and can perform dry or wet (with gel recordings. The results show it to be a versatile electrode that can evaluate the optimal configuration for the identification of the intestinal slow wave and reject undesired interference. A bipolar concentric record with an outer ring diameter of 30 mm, a foam-free adhesive material, and electrolytic gel gave the best results.

  4. TMS-induced cortical potentiation during wakefulness locally increases slow wave activity during sleep.

    Directory of Open Access Journals (Sweden)

    Reto Huber

    2007-03-01

    Full Text Available Sleep slow wave activity (SWA is thought to reflect sleep need, increasing in proportion to the length of prior wakefulness and decreasing during sleep. However, the process responsible for SWA regulation is not known. We showed recently that SWA increases locally after a learning task involving a circumscribed brain region, suggesting that SWA may reflect plastic changes triggered by learning.To test this hypothesis directly, we used transcranial magnetic stimulation (TMS in conjunction with high-density EEG in humans. We show that 5-Hz TMS applied to motor cortex induces a localized potentiation of TMS-evoked cortical EEG responses. We then show that, in the sleep episode following 5-Hz TMS, SWA increases markedly (+39.1+/-17.4%, p<0.01, n = 10. Electrode coregistration with magnetic resonance images localized the increase in SWA to the same premotor site as the maximum TMS-induced potentiation during wakefulness. Moreover, the magnitude of potentiation during wakefulness predicts the local increase in SWA during sleep.These results provide direct evidence for a link between plastic changes and the local regulation of sleep need.

  5. Fast and slow spindles during the sleep slow oscillation: disparate coalescence and engagement in memory processing.

    Science.gov (United States)

    Mölle, Matthias; Bergmann, Til O; Marshall, Lisa; Born, Jan

    2011-10-01

    Thalamo-cortical spindles driven by the up-state of neocortical slow (memory consolidation during sleep. We examined interactions between SOs and spindles in human slow wave sleep, focusing on the presumed existence of 2 kinds of spindles, i.e., slow frontocortical and fast centro-parietal spindles. Two experiments were performed in healthy humans (24.5 ± 0.9 y) investigating undisturbed sleep (Experiment I) and the effects of prior learning (word paired associates) vs. non-learning (Experiment II) on multichannel EEG recordings during sleep. Only fast spindles (12-15 Hz) were synchronized to the depolarizing SO up-state. Slow spindles (9-12 Hz) occurred preferentially at the transition into the SO down-state, i.e., during waning depolarization. Slow spindles also revealed a higher probability to follow rather than precede fast spindles. For sequences of individual SOs, fast spindle activity was largest for "initial" SOs, whereas SO amplitude and slow spindle activity were largest for succeeding SOs. Prior learning enhanced this pattern. The finding that fast and slow spindles occur at different times of the SO cycle points to disparate generating mechanisms for the 2 kinds of spindles. The reported temporal relationships during SO sequences suggest that fast spindles, driven by the SO up-state feed back to enhance the likelihood of succeeding SOs together with slow spindles. By enforcing such SO-spindle cycles, particularly after prior learning, fast spindles possibly play a key role in sleep-dependent memory processing.

  6. A Comparative Study of Dispersion Characteristics Determination of a Trapezoidally Corrugated Slow Wave Structure Using Different Techniques

    International Nuclear Information System (INIS)

    Saber, Md. Ghulam; Sagor, Rakibul Hasan; Amin, Md. Ruhul

    2016-01-01

    The linear dispersion relation of a trapezoidally corrugated slow wave structure (TCSWS) is analyzed and presented. The size parameters of the TCSWS are chosen in such a way that they operate in the x-band frequency range. The dispersion relation is solved by utilizing the Rayleigh–Fourier method by expressing the radial function in terms of the Fourier series. A highly accurate synthetic technique is also applied to determine the complete dispersion characteristics from experimentally measured resonances (cold test). Periodic structures resonate at specific frequencies when the terminals are shorted appropriately. The dispersion characteristics obtained from numerical calculation, synthetic technique and cold test are compared, and an excellent agreement is achieved. (paper)

  7. Contrast enema depiction of small-bowel volvulus in complicated neonatal bowel obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Oscar M.; Daneman, Alan; Miller, Stephen F. [Hospital for Sick Children, Department of Diagnostic Imaging, Toronto, ON (Canada)

    2004-12-01

    About one-half of patients with meconium ileus (MI) present with a complication such as volvulus, atresia, meconium peritonitis or giant cystic meconium peritonitis. The treatment of these complications requires surgery. However, the preoperative diagnosis of complicated MI is difficult. We describe two neonates with complicated small-bowel obstruction, one with MI related to cystic fibrosis and the other not related to cystic fibrosis. In both, contrast enema depicted a spiral appearance of the distal small bowel, which at surgery proved to be the result of volvulus associated with antenatal bowel perforation. This appearance of the small bowel on contrast enema in this clinical setting has not been previously described. The recognition of this spiral appearance of the distal small bowel suggests the need for surgery. (orig.)

  8. Contrast enema depiction of small-bowel volvulus in complicated neonatal bowel obstruction

    International Nuclear Information System (INIS)

    Navarro, Oscar M.; Daneman, Alan; Miller, Stephen F.

    2004-01-01

    About one-half of patients with meconium ileus (MI) present with a complication such as volvulus, atresia, meconium peritonitis or giant cystic meconium peritonitis. The treatment of these complications requires surgery. However, the preoperative diagnosis of complicated MI is difficult. We describe two neonates with complicated small-bowel obstruction, one with MI related to cystic fibrosis and the other not related to cystic fibrosis. In both, contrast enema depicted a spiral appearance of the distal small bowel, which at surgery proved to be the result of volvulus associated with antenatal bowel perforation. This appearance of the small bowel on contrast enema in this clinical setting has not been previously described. The recognition of this spiral appearance of the distal small bowel suggests the need for surgery. (orig.)

  9. The dream-lag effect: selective processing of personally significant events during Rapid Eye Movement sleep, but not during Slow Wave Sleep

    OpenAIRE

    van Rijn, E.; Eichenlaub, J.-B.; Lewis, Penelope A.; Walker, M.P.; Gaskell, M.G.; Malinowski, J.E.; Blagrove, M.

    2015-01-01

    Incorporation of details from waking life events into Rapid Eye Movement (REM) sleep dreams has been found to be highest on the night after, and then 5-7 nights after events (termed, respectively, the day-residue and dream-lag effects). In experiment 1, 44 participants kept a daily log for 10. days, reporting major daily activities (MDAs), personally significant events (PSEs), and major concerns (MCs). Dream reports were collected from REM and Slow Wave Sleep (SWS) in the laboratory, or from ...

  10. Interface waves propagating along tensile fractures in dolomite

    International Nuclear Information System (INIS)

    Roy, S.; Pyrak-Nolte, L.J.

    1995-01-01

    Elastic interface waves have been observed in induced tensile fractures in dolomite rock cores. Multiscaling wavelet analysis distinguishes the interface wave from bulk shear waves, quantifies the interface wave spectral content, and determines the arrival time of peak energy. The dominant seismic energy is concentrated in the slow interface wave, with little or no detectable energy in the fast wave. As stress across the fracture increases, the slow interface wave velocity increases, and the frequency of the spectral peak shifts to higher frequencies. The shear dynamic specific stiffness of the fracture was calculated from the peak energy arrival time as a function of stress. 13 refs., 5 figs., 1 tab

  11. Slowing down bubbles with sound

    Science.gov (United States)

    Poulain, Cedric; Dangla, Remie; Guinard, Marion

    2009-11-01

    We present experimental evidence that a bubble moving in a fluid in which a well-chosen acoustic noise is superimposed can be significantly slowed down even for moderate acoustic pressure. Through mean velocity measurements, we show that a condition for this effect to occur is for the acoustic noise spectrum to match or overlap the bubble's fundamental resonant mode. We render the bubble's oscillations and translational movements using high speed video. We show that radial oscillations (Rayleigh-Plesset type) have no effect on the mean velocity, while above a critical pressure, a parametric type instability (Faraday waves) is triggered and gives rise to nonlinear surface oscillations. We evidence that these surface waves are subharmonic and responsible for the bubble's drag increase. When the acoustic intensity is increased, Faraday modes interact and the strongly nonlinear oscillations behave randomly, leading to a random behavior of the bubble's trajectory and consequently to a higher slow down. Our observations may suggest new strategies for bubbly flow control, or two-phase microfluidic devices. It might also be applicable to other elastic objects, such as globules, cells or vesicles, for medical applications such as elasticity-based sorting.

  12. Multidetector row computed tomography in bowel obstruction. Part 2. Large bowel obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, R. [Department of Radiology, Glenfield Hospital, Leicester (United Kingdom)]. E-mail: rakesh.sinha@uhl-tr.nhs.uk; Verma, R. [Department of Radiology, Glenfield Hospital, Leicester (United Kingdom)

    2005-10-01

    Large bowel obstruction may present as an emergency as high-grade colonic obstruction and can result in perforation. Perforated large bowel obstruction causes faecal peritonitis, which can result in high morbidity and mortality. Multidetector row computed tomography (MDCT) has the potential of providing an accurate diagnosis of large bowel obstruction. The rapid acquisition of images within one breath-hold reduces misregistration artefacts than can occur in critically ill or uncooperative patients. The following is a review of the various causes of large bowel obstruction with emphasis on important pathogenic factors, CT appearances and the use of multiplanar reformatted images in the diagnostic workup.

  13. Standing Slow MHD Waves in Radiatively Cooling Coronal Loops ...

    Indian Academy of Sciences (India)

    The standing slow magneto-acoustic oscillations in cooling coronal loops ... turbation and, eventually, reduces the MHD equations to a 1D system modelling ..... where the function Q is expanded in power series with respect to ǫ, i.e.,. Q = Q0 + ...

  14. Efficiency enhancement of slow-wave electron-cyclotron maser by a second-order shaping of the magnetic field in the low-gain limit

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Si-Jia; Zhang, Yu-Fei; Wang, Kang [School of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Li, Yong-Ming [Information Science and Engineering College, XinJiang University, Urumqi XinJiang 830046 (China); Jing, Jian, E-mail: jingjian@mail.buct.edu.cn [School of Science, Beijing University of Chemical Technology, Beijing 100029 (China)

    2017-03-15

    Based on the anomalous Doppler effect, we put forward a proposal to enhance the conversion efficiency of the slow-wave electron cyclotron masers (ECM) under the resonance condition. Compared with previous studies, we add a second-order shaping term in the guild magnetic field. Theoretical analyses and numerical calculations show that it can enhance the conversion efficiency in the low-gain limit. The case of the initial velocity spread of electrons satisfying the Gaussian distribution is also analysed numerically.

  15. Traveling wave tube oscillator/amplifier with superconducting rf circuit

    International Nuclear Information System (INIS)

    Jasper, L.J. Jr.

    1989-01-01

    This patent describes a device comprising: an electron gun for producing an electron beam; a collector for collecting the electron beam; a vacuum housing surrounding the electron beam and having an integral slow wave circuit, the circuit being made from superconducting ceramic material; means for maintaining the temperature of the superconducting ceramic below its critical temperature; means for extracting an output signal from the slow wave circuit; means for creating a magnetic field within the vacuum housing so that interaction between the electron beam and the slow wave circuit produces the output signal

  16. Grating-assisted superresolution of slow waves in Fourier space

    DEFF Research Database (Denmark)

    Thomas, N. Le; Houdré, R.; Frandsen, Lars Hagedorn

    2007-01-01

    with a high numerical aperture Fourier space imaging set-up. A high-resolution spectroscopy of the far-field emission diagram allows us to accurately and efficiently determine the dispersion curve and the group-index dispersion of planar photonic waveguides operating in the slow light regime....

  17. Populations of striatal medium spiny neurons encode vibrotactile frequency in rats: modulation by slow wave oscillations.

    Science.gov (United States)

    Hawking, Thomas G; Gerdjikov, Todor V

    2013-01-01

    Dorsolateral striatum (DLS) is implicated in tactile perception and receives strong projections from somatosensory cortex. However, the sensory representations encoded by striatal projection neurons are not well understood. Here we characterized the contribution of DLS to the encoding of vibrotactile information in rats by assessing striatal responses to precise frequency stimuli delivered to a single vibrissa. We applied stimuli in a frequency range (45-90 Hz) that evokes discriminable percepts and carries most of the power of vibrissa vibration elicited by a range of complex fine textures. Both medium spiny neurons and evoked potentials showed tactile responses that were modulated by slow wave oscillations. Furthermore, medium spiny neuron population responses represented stimulus frequency on par with previously reported behavioral benchmarks. Our results suggest that striatum encodes frequency information of vibrotactile stimuli which is dynamically modulated by ongoing brain state.

  18. Observation of Magnetocoriolis Waves in a Liquid Metal Taylor-Couette Experiment

    International Nuclear Information System (INIS)

    Nornberg, M. D.; Ji, H.; Schartman, E.; Roach, A.; Goodman, J.

    2010-01-01

    The first observation of fast and slow magnetocoriolis (MC) waves in a laboratory experiment is reported. Rotating nonaxisymmetric modes arising from a magnetized turbulent Taylor-Couette flow of liquid metal are identified as the fast and slow MC waves by the dependence of the rotation frequency on the applied field strength. The observed slow MC wave is damped but the observation provides a means for predicting the onset of the magnetorotational instability.

  19. Observation of magnetocoriolis waves in a liquid metal Taylor-Couette experiment.

    Science.gov (United States)

    Nornberg, M D; Ji, H; Schartman, E; Roach, A; Goodman, J

    2010-02-19

    The first observation of fast and slow magnetocoriolis (MC) waves in a laboratory experiment is reported. Rotating nonaxisymmetric modes arising from a magnetized turbulent Taylor-Couette flow of liquid metal are identified as the fast and slow MC waves by the dependence of the rotation frequency on the applied field strength. The observed slow MC wave is damped but the observation provides a means for predicting the onset of the magnetorotational instability.

  20. Dispersion of extensional waves in fluid-saturated porous cylinders at ultrasonic frequencies

    International Nuclear Information System (INIS)

    Berryman, J.G.

    1983-01-01

    Ultrasonic dispersion of extensional waves in fluid-saturated porous cylinders is studied by analyzing generalized Pochhammer equations derived using Biot's theory. Cases with open-pore surface and closed-pore surface boundary conditions are considered. For both cases, the dispersion of the fast extensional wave does not differ much qualitatively from the dispersion expected for extensional waves in isotropic elastic cylinders. A slow extensional wave propagates in the case with a closed-pore surface but not in the case with an open-pore surface. The propagating slow wave has very weak dispersion and its speed is always lower than, but close to, the bulk slow wave speed

  1. Minimization of small bowel volume within treatment fields using customized small bowel displacement system (SBDS)

    International Nuclear Information System (INIS)

    Lim, D. H.; Huh, S. J.; Ahn, Y. C.; Kim, D. Y.; Wu, H. G.; Kim, M. K.; Choi, D. R.; Shin, K. H.

    1997-01-01

    Authors designed a customized Small Bowel Displacement System(SBDS) to displace the small bowel from the pelvic radiation fields and minimize treatment-related bowel morbidities. From August 1995 to May 1996, 55 consecutive patients who received pelvic radiation therapy with the SBDS were included in this study. The SBDS consists of a customized styrofoam compression device which can displace the small bowel from the radiation fields and an individualized immobilization abdominal board for easy daily setup in prone position. After opacifying the small bowel with Barium, the patients were laid prone and posterior-anterior (PA) and lateral (LAT) simulation films were taken with and without the SBDS. The areas of the small bowel included in the radiation fields with and without the SBDS were compared. Using the SBDS, the mean small bowel area was reduced by 59% on PA and 51% on LAT films (P=0.0001). In six patients (6/55, 11%), it was possible that no small bowel was included within the treatment fields. The mean upward displacement of the most caudal small bowel was 4.8 cm using the SBDS. Only 15% (8/55) of patients treated with the SBDS manifested diarrhea requiring medication. The SBDS is a novel method that can be used to displace the small bowel away from the treatment portal effectively and reduce the radiation therapy morbidities. Compliance with setup is excellent when the SBDS is used. (author)

  2. Gabor Wave Packet Method to Solve Plasma Wave Equations

    International Nuclear Information System (INIS)

    Pletzer, A.; Phillips, C.K.; Smithe, D.N.

    2003-01-01

    A numerical method for solving plasma wave equations arising in the context of mode conversion between the fast magnetosonic and the slow (e.g ion Bernstein) wave is presented. The numerical algorithm relies on the expansion of the solution in Gaussian wave packets known as Gabor functions, which have good resolution properties in both real and Fourier space. The wave packets are ideally suited to capture both the large and small wavelength features that characterize mode conversion problems. The accuracy of the scheme is compared with a standard finite element approach

  3. FIRST SIMULTANEOUS OBSERVATION OF AN H{alpha} MORETON WAVE, EUV WAVE, AND FILAMENT/PROMINENCE OSCILLATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Asai, Ayumi; Isobe, Hiroaki [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Ishii, Takako T.; Kitai, Reizaburo; Ichimoto, Kiyoshi; UeNo, Satoru; Nagata, Shin' ichi; Morita, Satoshi; Nishida, Keisuke; Shibata, Kazunari [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Shiota, Daikou [Advanced Science Institute, RIKEN, Wako, Saitama 351-0198 (Japan); Oi, Akihito [College of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Akioka, Maki, E-mail: asai@kwasan.kyoto-u.ac.jp [Hiraiso Solar Observatory, National Institute of Information and Communications Technology, Hitachinaka, Ibaraki 311-1202 (Japan)

    2012-02-15

    We report on the first simultaneous observation of an H{alpha} Moreton wave, the corresponding EUV fast coronal waves, and a slow and bright EUV wave (typical EIT wave). We observed a Moreton wave, associated with an X6.9 flare that occurred on 2011 August 9 at the active region NOAA 11263, in the H{alpha} images taken by the Solar Magnetic Activity Research Telescope at Hida Observatory of Kyoto University. In the EUV images obtained by the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory we found not only the corresponding EUV fast 'bright' coronal wave, but also the EUV fast 'faint' wave that is not associated with the H{alpha} Moreton wave. We also found a slow EUV wave, which corresponds to a typical EIT wave. Furthermore, we observed, for the first time, the oscillations of a prominence and a filament, simultaneously, both in the H{alpha} and EUV images. To trigger the oscillations by the flare-associated coronal disturbance, we expect a coronal wave as fast as the fast-mode MHD wave with the velocity of about 570-800 km s{sup -1}. These velocities are consistent with those of the observed Moreton wave and the EUV fast coronal wave.

  4. Interaction of rippled shock wave with flat fast-slow interface

    Science.gov (United States)

    Zhai, Zhigang; Liang, Yu; Liu, Lili; Ding, Juchun; Luo, Xisheng; Zou, Liyong

    2018-04-01

    The evolution of a flat air/sulfur-hexafluoride interface subjected to a rippled shock wave is investigated. Experimentally, the rippled shock wave is produced by diffracting a planar shock wave around solid cylinder(s), and the effects of the cylinder number and the spacing between cylinders on the interface evolution are considered. The flat interface is created by a soap film technique. The postshock flow and the evolution of the shocked interface are captured by a schlieren technique combined with a high-speed video camera. Numerical simulations are performed to provide more details of flows. The wave patterns of a planar shock wave diffracting around one cylinder or two cylinders are studied. The shock stability problem is analytically discussed, and the effects of the spacing between cylinders on shock stability are highlighted. The relationship between the amplitudes of the rippled shock wave and the shocked interface is determined in the single cylinder case. Subsequently, the interface morphologies and growth rates under different cases are obtained. The results show that the shock-shock interactions caused by multiple cylinders have significant influence on the interface evolution. Finally, a modified impulsive theory is proposed to predict the perturbation growth when multiple solid cylinders are present.

  5. Vedolizumab in Paediatric Inflammatory Bowel Disease

    DEFF Research Database (Denmark)

    Ledder, Oren; Assa, Amit; Levine, Arie

    2017-01-01

    Background: Vedolizumab, an anti-integrin antibody, has proven to be effective in adults with inflammatory bowel disease [IBD], but the data in paediatrics are limited. We describe the short-term effectiveness and safety of vedolizumab in a European multi-centre paediatric IBD cohort. Method......: Retrospective review of children [aged 2-18 years] treated with vedolizumab from 19 centres affiliated with the Paediatric IBD Porto group of ESPGHAN. Primary outcome was Week 14 corticosteroid-free remission [CFR]. Results: In all, 64 children were included (32 [50%] male, mean age 14.5 ± 2.8 years...... minor drug-related adverse events. Only 3 of 16 children who underwent endoscopic evaluation had mucosal healing after treatment (19%). Conclusions: Vedolizumab was safe and effective in this cohort of paediatric refractory IBD. These data support previous findings of slow induction rate of vedolizumab...

  6. Irritable Bowel Syndrome

    Science.gov (United States)

    ... your belly area), constipation (when you can't poop), and diarrhea (when you poop too much). If you have irritable bowel syndrome, ... food particles are also known as stool, a bowel movement, or poop. Here's why an intestine gets "irritable." ...

  7. Stricturoplasty—a bowel-sparing option for long segment small bowel Crohn's disease

    OpenAIRE

    Limmer, Alexandra M.; Koh, Hoey C.; Gilmore, Andrew

    2017-01-01

    Abstract Stricturoplasty is a surgical option for management of severe stricturing Crohn's disease of the small bowel. It avoids the need for small bowel resection and the associated metabolic complications. This report contrasts the indications and technical aspects of two different stricturoplasty techniques. Case 1 describes an extensive Michelassi (side-to-side isoperistaltic) stricturoplasty performed for a 100 cm segment of diseased small bowel in a 45-year-old patient. Case 2 describes...

  8. Identifying decreased peristalsis of abnormal small bowel segments in Crohn's disease using cine MR enterography: the frozen bowel sign.

    Science.gov (United States)

    Guglielmo, Flavius F; Mitchell, Donald G; O'Kane, Patrick L; Deshmukh, Sandeep P; Roth, Christopher G; Burach, Ilene; Burns, Aaron; Dulka, Susan; Parker, Laurence

    2015-06-01

    The purpose of this study was to evaluate whether affected bowel in Crohn's disease patients can be identified by observing decreased peristalsis (frozen bowel sign) using cine balanced steady-state free precession (cine BSSFP) images. 5 radiologists independently reviewed cine BSSFP sequences from randomized MR Enterography (MRE) exams for 30 normal and 30 Crohn's disease patients, graded overall small bowel peristalsis from slowest to fastest, and graded peristalsis for the most abnormal small bowel segment. Sensitivity and specificity of the frozen bowel sign for diagnosing Crohn's disease were calculated. T tests of the peristalsis difference between abnormal segments and overall small bowel were conducted. For 5 readers, the sensitivity and specificity of cine BSSFP of the frozen bowel sign for diagnosing Crohn's disease ranged from 70% to 100% and 87% to 100%, respectively. There were significant differences in peristalsis between abnormal small bowel segments and the overall small bowel for Crohn's patients, but not in the overall small bowel between normal-MRE patients and Crohn's disease patients. Abnormal Crohn's small bowel segments have significantly decreased peristalsis compared to normal small bowel, which can be identified using cine BSSFP sequences as the frozen bowel sign.

  9. Ostomy Surgery of the Bowel

    Science.gov (United States)

    ... Digestive System & How it Works Zollinger-Ellison Syndrome Ostomy Surgery of the Bowel What is ostomy surgery of the bowel? Ostomy surgery of the ... of the body. Why does a person need ostomy surgery of the bowel? A person may need ...

  10. Irritable bowel syndrome: Is it "irritable brain" or "irritable bowel"?

    Directory of Open Access Journals (Sweden)

    Susanta Kumar Padhy

    2015-01-01

    Full Text Available Irritable bowel syndrome (IBS has been recognized as one of the most common and best studied disorders among the group of functional gastrointestinal disorders. It is a functional bowel disorder in which abdominal pain or discomfort is associated with defecation or a change in bowel habit. In the Western world, IBS appears to affect up to 20% of the population at any given time but in Asian countries, the median value of IBS prevalence defined by various criteria ranges between 6.5% and 10.1%, and community prevalence of 4% is found in North India. Those attending gastroenterology clinics represent only the tip of the iceberg. The disorder substantially impairs the quality of life, and the overall health-care costs are high. IBS has therefore gained increased attention from clinicians, researchers, and pharmaceutical industries. It is often frustrating to both patients and physicians as the disease is usually chronic in nature and difficult to treat. However, the understanding of IBS has been changing from time to time and still most of its concepts are unknown. In this review we have discussed, debated, and synthesized the evidence base, focusing on underlying mechanisms in the brain and bowel. We conclude that it is both brain and bowel mechanisms that are responsible. The clinical implication of such mechanisms is discussed.

  11. On phase and ray directions of magnetosonic waves

    International Nuclear Information System (INIS)

    Lerche, I.

    1978-01-01

    The behavior of phase speed for the 'slow' and 'fast' magnetosonic waves is well documented in the literature. Not so well documented is the behavior of the ray direction and its relation to the phase direction - indeed the author has not found the ray behavior recorded in most of the standard plasma physics texts. This situation is rectified and some of the curiosities associated with the direction of the 'slow' ray relative to the direction of the 'slow' phase wave are pointed out. These calculations have been performed as a necessary basis for discussion of phase and ray evolution of magnetosonic waves in differentially shearing plasmas, which subject is the topic of a later paper. (Auth.)

  12. Bowel preparation for CT colonography

    International Nuclear Information System (INIS)

    Neri, Emanuele; Lefere, Philippe; Gryspeerdt, Stefaan; Bemi, Pietro; Mantarro, Annalisa; Bartolozzi, Carlo

    2013-01-01

    Bowel preparation represents an essential part of CT colonography, as the accuracy of the exam is strongly related to the adequacy of colonic cleansing, and a poor bowel preparation may compromise the diagnostic quality even despite optimization of all other acquisition parameters. Residual stool and fluid in the large bowel may affect the interpretation of the exam and may increase the number of false positives and false negatives. In this regard, the majority of patients having undergone CT colonography state that bowel preparation is the most unpleasant part. Unfortunately, to date no definite consensus has been reached about the ideal bowel preparation technique, and there is great variability in preparation strategies across diagnostic centers. The purpose of this review article is to describe the development and evolution of bowel preparation techniques in order to choose the best approach for optimizing the diagnostic quality of CT colonography in each patient

  13. Bowel preparation for CT colonography

    Energy Technology Data Exchange (ETDEWEB)

    Neri, Emanuele, E-mail: emanuele.neri@med.unipi.it [Diagnostic and Interventional Radiology, University of Pisa (Italy); Lefere, Philippe; Gryspeerdt, Stefaan [Department of Radiology, Stedelijk Ziekenhuis, Roeselare (Belgium); Bemi, Pietro; Mantarro, Annalisa; Bartolozzi, Carlo [Diagnostic and Interventional Radiology, University of Pisa (Italy)

    2013-08-15

    Bowel preparation represents an essential part of CT colonography, as the accuracy of the exam is strongly related to the adequacy of colonic cleansing, and a poor bowel preparation may compromise the diagnostic quality even despite optimization of all other acquisition parameters. Residual stool and fluid in the large bowel may affect the interpretation of the exam and may increase the number of false positives and false negatives. In this regard, the majority of patients having undergone CT colonography state that bowel preparation is the most unpleasant part. Unfortunately, to date no definite consensus has been reached about the ideal bowel preparation technique, and there is great variability in preparation strategies across diagnostic centers. The purpose of this review article is to describe the development and evolution of bowel preparation techniques in order to choose the best approach for optimizing the diagnostic quality of CT colonography in each patient.

  14. Spatial organization and coordination of slow waves in the mouse anorectum

    Science.gov (United States)

    Hall, K A; Ward, S M; Cobine, C A; Keef, K D

    2014-01-01

    The internal anal sphincter (IAS) develops tone and is important for maintaining a high anal pressure while tone in the rectum is less. The mechanisms responsible for tone generation in the IAS are still uncertain. The present study addressed this question by comparing the electrical properties and morphology of the mouse IAS and distal rectum. The amplitude of tone and the frequency of phasic contractions was greater in the IAS than in rectum while membrane potential (Em) was less negative in the IAS than in rectum. Slow waves (SWs) were of greatest amplitude and frequency at the distal end of the IAS, declining in the oral direction. Dual microelectrode recordings revealed that SWs were coordinated over a much greater distance in the circumferential direction than in the oral direction. The circular muscle layer of the IAS was divided into five to eight ‘minibundles’ separated by connective tissue septa whereas few septa were present in the rectum. The limited coordination of SWs in the oral direction suggests that the activity in adjacent minibundles is not coordinated. Intramuscular interstitial cells of Cajal and platelet-derived growth factor receptor alpha-positive cells were present in each minibundle suggesting a role for one or both of these cells in SW generation. In summary, three important properties distinguish the IAS from the distal rectum: (1) a more depolarized Em; (2) larger and higher frequency SWs; and (3) the multiunit configuration of the muscle. All of these characteristics may contribute to greater tone generation in the IAS than in the distal rectum. PMID:24951622

  15. Slow oscillating transcranial direct current stimulation during sleep has a sleep-stabilizing effect in chronic insomnia: a pilot study.

    Science.gov (United States)

    Saebipour, Mohammad R; Joghataei, Mohammad T; Yoonessi, Ali; Sadeghniiat-Haghighi, Khosro; Khalighinejad, Nima; Khademi, Soroush

    2015-10-01

    Recent evidence suggests that lack of slow-wave activity may play a fundamental role in the pathogenesis of insomnia. Pharmacological approaches and brain stimulation techniques have recently offered solutions for increasing slow-wave activity during sleep. We used slow (0.75 Hz) oscillatory transcranial direct current stimulation during stage 2 of non-rapid eye movement sleeping insomnia patients for resonating their brain waves to the frequency of sleep slow-wave. Six patients diagnosed with either sleep maintenance or non-restorative sleep insomnia entered the study. After 1 night of adaptation and 1 night of baseline polysomnography, patients randomly received sham or real stimulation on the third and fourth night of the experiment. Our preliminary results show that after termination of stimulations (sham or real), slow oscillatory transcranial direct current stimulation increased the duration of stage 3 of non-rapid eye movement sleep by 33 ± 26 min (P = 0.026), and decreased stage 1 of non-rapid eye movement sleep duration by 22 ± 17.7 min (P = 0.028), compared with sham. Slow oscillatory transcranial direct current stimulation decreased stage 1 of non-rapid eye movement sleep and wake time after sleep-onset durations, together, by 55.4 ± 51 min (P = 0.045). Slow oscillatory transcranial direct current stimulation also increased sleep efficiency by 9 ± 7% (P = 0.026), and probability of transition from stage 2 to stage 3 of non-rapid eye movement sleep by 20 ± 17.8% (P = 0.04). Meanwhile, slow oscillatory transcranial direct current stimulation decreased transitions from stage 2 of non-rapid eye movement sleep to wake by 12 ± 6.7% (P = 0.007). Our preliminary results suggest a sleep-stabilizing role for the intervention, which may mimic the effect of sleep slow-wave-enhancing drugs. © 2015 European Sleep Research Society.

  16. Adenocarcinoma of the small bowel

    International Nuclear Information System (INIS)

    Savli, M.; Jamar, B.

    2007-01-01

    Adenocarcinoma of small bowel is generally a rather rare primary tumour of small bowel with a prevalence rate of 0.5 - 3.0 / 100.000 population, but the most frequent tumour of small intestine. It more often involves the duodenum and jejunum than the ileum. The aim of this paper is also to point out the value of small bowel follow through (SBFT) in the diagnosis of stenosing lesions. An 83 - year old male patient suffered from abdominal pain, malaise, vomiting, cachexia and diarrhoea for 3 months. The result of occult blood testing was negative. Haemoglobin level was normal. Proctoscopy, colonoscopy, upper gastrointestinal (GI) endoscopy, and ultrasonography (US) did not explain the patient's problems. Ileus of the small bowel was established with abdominal plain film. Small bowel follow through (SBFT) and computer tomography (CT) showed a stenosing tumour in the jejunum. Adenocarcinoma of the small bowel was established with histological examination after resection of the tumor. SBFT, with manual compression of all segments of the small bowel, can be a very accurate diagnostic investigation for evaluation of stenosing lesions in this part of the intestine. (author)

  17. Adenocarcinoma of the small bowel

    Energy Technology Data Exchange (ETDEWEB)

    Savli, M; Jamar, B [Inst. of Clinical Radiology, Univ. Medical Centre, Ljubljana (Slovenia)

    2007-06-15

    Adenocarcinoma of small bowel is generally a rather rare primary tumour of small bowel with a prevalence rate of 0.5 - 3.0 / 100.000 population, but the most frequent tumour of small intestine. It more often involves the duodenum and jejunum than the ileum. The aim of this paper is also to point out the value of small bowel follow through (SBFT) in the diagnosis of stenosing lesions. An 83 - year old male patient suffered from abdominal pain, malaise, vomiting, cachexia and diarrhoea for 3 months. The result of occult blood testing was negative. Haemoglobin level was normal. Proctoscopy, colonoscopy, upper gastrointestinal (GI) endoscopy, and ultrasonography (US) did not explain the patient's problems. Ileus of the small bowel was established with abdominal plain film. Small bowel follow through (SBFT) and computer tomography (CT) showed a stenosing tumour in the jejunum. Adenocarcinoma of the small bowel was established with histological examination after resection of the tumor. SBFT, with manual compression of all segments of the small bowel, can be a very accurate diagnostic investigation for evaluation of stenosing lesions in this part of the intestine. (author)

  18. A Ku-band magnetically insulated transmission line oscillator with overmoded slow-wave-structure

    Science.gov (United States)

    Jiang, Tao; He, Jun-Tao; Zhang, Jian-De; Li, Zhi-Qiang; Ling, Jun-Pu

    2016-12-01

    In order to enhance the power capacity, an improved Ku-band magnetically insulated transmission line oscillator (MILO) with overmoded slow-wave-structure (SWS) is proposed and investigated numerically and experimentally. The analysis of the dispersion relationship and the resonant curve of the cold test indicate that the device can operate at the near π mode of the TM01 mode, which is useful for mode selection and control. In the particle simulation, the improved Ku-band MILO generates a microwave with a power of 1.5 GW and a frequency of 12.3 GHz under an input voltage of 480 kV and input current of 42 kA. Finally, experimental investigation of the improved Ku-band MILO is carried out. A high-power microwave (HPM) with an average power of 800 MW, a frequency of 12.35 GHz, and pulse width of 35 ns is generated under a diode voltage of 500 kV and beam current of 43 kA. The consistency between the experimental and simulated far-field radiation pattern confirms that the operating mode of the improved Ku-band MILO is well controlled in π mode of the TM01 mode. Project supported partly by the National Natural Science Foundation of China (Grant No. 61171021).

  19. Slow light based on material and waveguide dispersion

    DEFF Research Database (Denmark)

    Nielsen, Torben Roland; Lavrinenko, Andrei; Mørk, Jesper

    2009-01-01

    We study slow light pulse propagation in a photonic crystal structure consisting of a dispersive and absorptive dielectric material and compare it with the constant wave case. The group index and the trasmission are investigated for the example of an ensemble of semiconductor quantum dots embedded...

  20. Ageing with neurogenic bowel dysfunction

    DEFF Research Database (Denmark)

    Nielsen, S D; Faaborg, Pia Møller; Finnerup, Nanna Brix

    2017-01-01

    The aim of this longitudinal study with postal survey was to describe changes in the patterns of neurogenic bowel dysfunction and bowel management in a population of people with spinal cord injury (SCI) followed for two decades. In 1996, a validated questionnaire on bowel function was sent to the...

  1. Traveling-Wave Maser for 32 GHz

    Science.gov (United States)

    Shell, James; Clauss, Robert

    2009-01-01

    The figure depicts a traveling-wave ruby maser that has been designed (though not yet implemented in hardware) to serve as a low-noise amplifier for reception of weak radio signals in the frequency band of 31.8 to 32.3 GHz. The design offers significant improvements over previous designs of 32-GHz traveling-wave masers. In addition, relative to prior designs of 32-GHz amplifiers based on high-electron-mobility transistors, this design affords higher immunity to radio-frequency interference and lower equivalent input noise temperature. In addition to the basic frequency-band and low-noise requirements, the initial design problem included a requirement for capability of operation in a closed-cycle helium refrigerator at a temperature .4 K and a requirement that the design be mechanically simplified, relative to prior designs, in order to minimize the cost of fabrication and assembly. Previous attempts to build 32- GHz traveling-wave masers involved the use of metallic slow-wave structures comprising coupled transverse electromagnetic (TEM)-mode resonators that were subject to very tight tolerances and, hence, were expensive to fabricate and assemble. Impedance matching for coupling signals into and out of these earlier masers was very difficult. A key feature of the design is a slow-wave structure, the metallic portions of which would be mechanically relatively simple in that, unlike in prior slow-wave structures, there would be no internal metal steps, irises, or posts. The metallic portions of the slow-wave structure would consist only of two rectangular metal waveguide arms. The arms would contain sections filled with the active material (ruby) alternating with evanescent-wave sections. This structure would be transparent in both the signal-frequency band (the aforementioned range of 31.8 to 32.3 GHz) and the pump-frequency band (65.75 to 66.75 GHz), and would impose large slowing factors in both frequency bands. Resonant ferrite isolators would be placed in the

  2. Phase of Spontaneous Slow Oscillations during Sleep Influences Memory-Related Processing of Auditory Cues.

    Science.gov (United States)

    Batterink, Laura J; Creery, Jessica D; Paller, Ken A

    2016-01-27

    Slow oscillations during slow-wave sleep (SWS) may facilitate memory consolidation by regulating interactions between hippocampal and cortical networks. Slow oscillations appear as high-amplitude, synchronized EEG activity, corresponding to upstates of neuronal depolarization and downstates of hyperpolarization. Memory reactivations occur spontaneously during SWS, and can also be induced by presenting learning-related cues associated with a prior learning episode during sleep. This technique, targeted memory reactivation (TMR), selectively enhances memory consolidation. Given that memory reactivation is thought to occur preferentially during the slow-oscillation upstate, we hypothesized that TMR stimulation effects would depend on the phase of the slow oscillation. Participants learned arbitrary spatial locations for objects that were each paired with a characteristic sound (eg, cat-meow). Then, during SWS periods of an afternoon nap, one-half of the sounds were presented at low intensity. When object location memory was subsequently tested, recall accuracy was significantly better for those objects cued during sleep. We report here for the first time that this memory benefit was predicted by slow-wave phase at the time of stimulation. For cued objects, location memories were categorized according to amount of forgetting from pre- to post-nap. Conditions of high versus low forgetting corresponded to stimulation timing at different slow-oscillation phases, suggesting that learning-related stimuli were more likely to be processed and trigger memory reactivation when they occurred at the optimal phase of a slow oscillation. These findings provide insight into mechanisms of memory reactivation during sleep, supporting the idea that reactivation is most likely during cortical upstates. Slow-wave sleep (SWS) is characterized by synchronized neural activity alternating between active upstates and quiet downstates. The slow-oscillation upstates are thought to provide a

  3. Stricturoplasty-a bowel-sparing option for long segment small bowel Crohn's disease.

    Science.gov (United States)

    Limmer, Alexandra M; Koh, Hoey C; Gilmore, Andrew

    2017-08-01

    Stricturoplasty is a surgical option for management of severe stricturing Crohn's disease of the small bowel. It avoids the need for small bowel resection and the associated metabolic complications. This report contrasts the indications and technical aspects of two different stricturoplasty techniques. Case 1 describes an extensive Michelassi (side-to-side isoperistaltic) stricturoplasty performed for a 100 cm segment of diseased small bowel in a 45-year-old patient. Case 2 describes the performance of 12 Heineke-Mikulicz stricturoplasties in a 23-year-old patient with multiple short fibrotic strictures.

  4. Bowel injury following gynecological laparoscopic surgery.

    African Journals Online (AJOL)

    Keywords: Laparoscopy, gynaecology, injury, bowel, prevention, treatment. ... cluding less post-operative pain, earlier return of normal bowel function, shorter hospital ... and presence of previous abdominal surgery increase the risk of bowel ...

  5. Accuracy of abdominal auscultation for bowel obstruction

    DEFF Research Database (Denmark)

    Breum, Birger Michael; Rud, Bo; Kirkegaard, Thomas

    2015-01-01

    AIM: To investigate the accuracy and inter-observer variation of bowel sound assessment in patients with clinically suspected bowel obstruction. METHODS: Bowel sounds were recorded in patients with suspected bowel obstruction using a Littmann(®) Electronic Stethoscope. The recordings were process...

  6. Oral contrast agents for small bowel MRI: comparison of different additives to optimize bowel distension

    Energy Technology Data Exchange (ETDEWEB)

    Ajaj, Waleed; Goehde, Susanne C.; Ruehm, Stefan G.; Debatin, Joerg F.; Lauenstein, Thomas C. [Department of Diagnostic and Interventional Radiology, University Hospital Essen, Hufelandstrasse 55, 45122, Essen (Germany); Schneemann, Hubert [Institute of Pharmacy and Pharmaceutical Sciences, University Hospital Essen, Essen (Germany)

    2004-03-01

    The purpose of this study was to compare two osmotic carbohydrate sugar alcohols (mannitol 2.5% and sorbitol 2.5%, 2.0%, and 1.5% watery solutions) in combination with 0.2% locust bean gum (LBG) for small bowel distension for MR imaging. Small bowel distension was quantified on coronal 2D TrueFISP images by measuring the diameters of 16 small bowel loops in each of 12 healthy subjects (age range 31-55 years). Additionally, the grade of small bowel distension was rated qualitatively. Patient acceptance concerning nausea, vomiting, flatulence, and diarrhea was noted for each solution, and all results were compared by a Wilcoxon test or t test, respectively. The ingestion of water combined with LBG and either 2.5% mannitol or 2.0% sorbitol showed the best distension of the small bowel. The lowest side effect rate was observed following ingestion of sorbitol in a concentration of 2.0 and 1.5%. Based on these data, we recommend a combination of LBG and 2% sorbitol use for optimal bowel distension and minimal side effects resulting in enhanced patient acceptance. (orig.)

  7. Oral contrast agents for small bowel MRI: comparison of different additives to optimize bowel distension

    International Nuclear Information System (INIS)

    Ajaj, Waleed; Goehde, Susanne C.; Ruehm, Stefan G.; Debatin, Joerg F.; Lauenstein, Thomas C.; Schneemann, Hubert

    2004-01-01

    The purpose of this study was to compare two osmotic carbohydrate sugar alcohols (mannitol 2.5% and sorbitol 2.5%, 2.0%, and 1.5% watery solutions) in combination with 0.2% locust bean gum (LBG) for small bowel distension for MR imaging. Small bowel distension was quantified on coronal 2D TrueFISP images by measuring the diameters of 16 small bowel loops in each of 12 healthy subjects (age range 31-55 years). Additionally, the grade of small bowel distension was rated qualitatively. Patient acceptance concerning nausea, vomiting, flatulence, and diarrhea was noted for each solution, and all results were compared by a Wilcoxon test or t test, respectively. The ingestion of water combined with LBG and either 2.5% mannitol or 2.0% sorbitol showed the best distension of the small bowel. The lowest side effect rate was observed following ingestion of sorbitol in a concentration of 2.0 and 1.5%. Based on these data, we recommend a combination of LBG and 2% sorbitol use for optimal bowel distension and minimal side effects resulting in enhanced patient acceptance. (orig.)

  8. FROM SLOW FOOD TO SLOW TOURISM

    Directory of Open Access Journals (Sweden)

    Bac Dorin Paul

    2014-12-01

    Full Text Available One of the effects of globalization is the faster pace of our lives. This rhythm can be noticed in all aspects of life: travel, work, shopping, etc. and it has serious negative effects. It has become common knowledge that stress and speed generate serious medical issues. Food and eating habits in the modern world have taken their toll on our health. However, some people took a stand and argued for a new kind of lifestyle. It all started in the field of gastronomy, where a new movement emerged – Slow Food, based on the ideas and philosophy of Carlo Petrini. Slow Food represents an important adversary to the concept of fast food, and is promoting local products, enjoyable meals and healthy food. The philosophy of the Slow Food movement developed in several directions: Cittaslow, slow travel and tourism, slow religion and slow money etc. The present paper will account the evolution of the concept and its development during the most recent years. We will present how the philosophy of slow food was applied in all the other fields it reached and some critical points of view. Also we will focus on the presence of the slow movement in Romania, although it is in a very early stage of development. The main objectives of the present paper are: to present the chronological and ideological evolution of the slow movement; to establish a clear separation of slow travel and slow tourism, as many mistake on for the other; to review the presence of the slow movement in Romania. Regarding the research methodology, information was gathered from relevant academic papers and books and also from interviews and discussions with local entrepreneurs. The research is mostly theoretical and empirical, as slow food and slow tourism are emerging research themes in academic circles.

  9. APPARENT CROSS-FIELD SUPERSLOW PROPAGATION OF MAGNETOHYDRODYNAMIC WAVES IN SOLAR PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, T.; Yokoyama, T. [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan); Goossens, M.; Doorsselaere, T. Van [Centre for Mathematical Plasma Astrophysics, Katholieke Universiteit Leuven, Celestijnenlaan 200B, Bus 2400, B-3001 Herverlee (Belgium); Soler, R.; Terradas, J. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Wright, A. N., E-mail: kaneko@eps.s.u-tokyo.ac.jp [School of Mathematics and Statistics, University of St Andrews, St Andrews, KY16 9SS (United Kingdom)

    2015-10-20

    In this paper we show that the phase-mixing of continuum Alfvén waves and/or continuum slow waves in the magnetic structures of the solar atmosphere as, e.g., coronal arcades, can create the illusion of wave propagation across the magnetic field. This phenomenon could be erroneously interpreted as fast magnetosonic waves. The cross-field propagation due to the phase-mixing of continuum waves is apparent because there is no real propagation of energy across the magnetic surfaces. We investigate the continuous Alfvén and slow spectra in two-dimensional (2D) Cartesian equilibrium models with a purely poloidal magnetic field. We show that apparent superslow propagation across the magnetic surfaces in solar coronal structures is a consequence of the existence of continuum Alfvén waves and continuum slow waves that naturally live on those structures and phase-mix as time evolves. The apparent cross-field phase velocity is related to the spatial variation of the local Alfvén/slow frequency across the magnetic surfaces and is slower than the Alfvén/sound velocities for typical coronal conditions. Understanding the nature of the apparent cross-field propagation is important for the correct analysis of numerical simulations and the correct interpretation of observations.

  10. Bowel vaginoplasty in children

    Directory of Open Access Journals (Sweden)

    Sarin Yogesh

    2006-01-01

    Full Text Available OBJECTIVES: To describe our experience with bowel vaginoplasty done in children. MATERIALS AND METHODS: This is a retrospective study of eight children aged 10 months to 8 years, who underwent bowel vaginoplasty over a period of 5 years (2000-2005. The indications of bowel vaginoplasty included anorectovestibular fistula (ARVF associated with Mayer-Rokitansky-Kuster-Hauser (MRKH syndrome (n=6 and cloaca (n=2. The bowel segment used for vaginoplasty included colon (n=3, ileum (n=2 and duplicated rectum (n=1. In two patients of ARVF associated with uterovaginal agenesis, the distal- most part of ARVF was transected at the level of peritoneal reflection and left as neovagina, whereas the proximal bowel was pulled through at the proposed neo-anal site. All the patients were advised daily home dilatation of the neo vaginal orifice with Hegar′s dilators, for a period of six weeks. RESULTS: Bowel vaginoplasty was done in eight patients. None had any significant per-operative complication. Two patients had abdominal wound dehiscence, requiring secondary suturing. Two patients had mucosal prolapse of the neovagina, which required trimming. One patient died two months after discharge, because of meningitis. Out of the eight patients, seven are in regular follow-up. Six patients have neovagina, cosmetically acceptable to the parents; all have been radiologically proven to have adequate length. One patient had unacceptable perineal appearance with nipple-like vaginal orifice and scarred perineal wound, that merits a revision. None of the patients had vaginal stenosis and excessive mucus discharge, during follow-up visits. Although post surgical results are acceptable to the parents cosmetically, the sexual and psychological outcome is yet to be assessed. Conclusions: Bowel vaginoplasty is a safe and acceptable procedure to treat the pediatric patients of uterovaginal agenesis and cloaca.

  11. Accuracy of abdominal auscultation for bowel obstruction.

    Science.gov (United States)

    Breum, Birger Michael; Rud, Bo; Kirkegaard, Thomas; Nordentoft, Tyge

    2015-09-14

    To investigate the accuracy and inter-observer variation of bowel sound assessment in patients with clinically suspected bowel obstruction. Bowel sounds were recorded in patients with suspected bowel obstruction using a Littmann(®) Electronic Stethoscope. The recordings were processed to yield 25-s sound sequences in random order on PCs. Observers, recruited from doctors within the department, classified the sound sequences as either normal or pathological. The reference tests for bowel obstruction were intraoperative and endoscopic findings and clinical follow up. Sensitivity and specificity were calculated for each observer and compared between junior and senior doctors. Interobserver variation was measured using the Kappa statistic. Bowel sound sequences from 98 patients were assessed by 53 (33 junior and 20 senior) doctors. Laparotomy was performed in 47 patients, 35 of whom had bowel obstruction. Two patients underwent colorectal stenting due to large bowel obstruction. The median sensitivity and specificity was 0.42 (range: 0.19-0.64) and 0.78 (range: 0.35-0.98), respectively. There was no significant difference in accuracy between junior and senior doctors. The median frequency with which doctors classified bowel sounds as abnormal did not differ significantly between patients with and without bowel obstruction (26% vs 23%, P = 0.08). The 53 doctors made up 1378 unique pairs and the median Kappa value was 0.29 (range: -0.15-0.66). Accuracy and inter-observer agreement was generally low. Clinical decisions in patients with possible bowel obstruction should not be based on auscultatory assessment of bowel sounds.

  12. Long-lasting novelty-induced neuronal reverberation during slow-wave sleep in multiple forebrain areas.

    Directory of Open Access Journals (Sweden)

    Sidarta Ribeiro

    2004-01-01

    Full Text Available The discovery of experience-dependent brain reactivation during both slow-wave (SW and rapid eye-movement (REM sleep led to the notion that the consolidation of recently acquired memory traces requires neural replay during sleep. To date, however, several observations continue to undermine this hypothesis. To address some of these objections, we investigated the effects of a transient novel experience on the long-term evolution of ongoing neuronal activity in the rat forebrain. We observed that spatiotemporal patterns of neuronal ensemble activity originally produced by the tactile exploration of novel objects recurred for up to 48 h in the cerebral cortex, hippocampus, putamen, and thalamus. This novelty-induced recurrence was characterized by low but significant correlations values. Nearly identical results were found for neuronal activity sampled when animals were moving between objects without touching them. In contrast, negligible recurrence was observed for neuronal patterns obtained when animals explored a familiar environment. While the reverberation of past patterns of neuronal activity was strongest during SW sleep, waking was correlated with a decrease of neuronal reverberation. REM sleep showed more variable results across animals. In contrast with data from hippocampal place cells, we found no evidence of time compression or expansion of neuronal reverberation in any of the sampled forebrain areas. Our results indicate that persistent experience-dependent neuronal reverberation is a general property of multiple forebrain structures. It does not consist of an exact replay of previous activity, but instead it defines a mild and consistent bias towards salient neural ensemble firing patterns. These results are compatible with a slow and progressive process of memory consolidation, reflecting novelty-related neuronal ensemble relationships that seem to be context- rather than stimulus-specific. Based on our current and previous results

  13. Bowel injury following gynecological laparoscopic surgery.

    African Journals Online (AJOL)

    nique did not reduce bowel injuries.6 Majority of gyne- .... showed (A-B) distended small bowel loops (yellow arrows) and an incarcerated bowel loop in one of the ... intolerance of oral intake, bloating, nausea, fever or diar- ..... Strategies in.

  14. Effects of a 5-HT(3) antagonist, ondansetron, on fasting and postprandial small bowel water content assessed by magnetic resonance imaging.

    Science.gov (United States)

    Marciani, L; Wright, J; Foley, S; Hoad, C L; Totman, J J; Bush, D; Hartley, C; Armstrong, A; Manby, P; Blackshaw, E; Perkins, A C; Gowland, P A; Spiller, R C

    2010-09-01

    5-HT(3) antagonists have been shown to be effective in relieving the symptoms of irritable bowel syndrome with diarrhoea (IBS-D). Using a recently validated magnetic resonance imaging (MRI) method, we have demonstrated reduced fasting small bowel water content (SBWC) in IBS-D associated with accelerated small bowel transit. We hypothesized that slowing of transit with ondansetron would lead to an increase in SBWC by inhibiting fasting motility. To assess the effects of ondansetron compared with placebo in healthy volunteers on SBWC and motility in two different groups of subjects, one studied using MRI and another using manometry. Healthy volunteers were given either a placebo or ondansetron on the day prior to and on the study day. Sixteen volunteers underwent baseline fasting and postprandial MRI scans for 270 min. In a second study, a separate group of n = 18 volunteers were intubated and overnight migrating motor complex (MMC) recorded. Baseline MRI scans were carried out after the tube was removed. Fasting SBWC was markedly increased by ondansetron (P fasting SBWC (P fasting small bowel water. This was associated with reduced fasting antroduodenal Motility Index which may explain the clinical benefit of such drugs. 2010 Blackwell Publishing Ltd.

  15. Fetal bowel anomalies - US and MR assessment

    Energy Technology Data Exchange (ETDEWEB)

    Rubesova, Erika [Stanford University, Department of Radiology, Lucile Packard Children' s Hospital, Stanford, CA (United States)

    2012-01-15

    The technical quality of prenatal US and fetal MRI has significantly improved during the last decade and allows an accurate diagnosis of bowel pathology prenatally. Accurate diagnosis of bowel pathology in utero is important for parental counseling and postnatal management. It is essential to recognize the US presentation of bowel pathology in the fetus in order to refer the patient for further evaluation or follow-up. Fetal MRI has been shown to offer some advantages over US for specific bowel abnormalities. In this paper, we review the normal appearance of the fetal bowel on US and MRI as well as the typical presentations of bowel pathologies. We discuss more specifically the importance of recognizing on fetal MRI the abnormalities of size and T1-weighted signal of the meconium-filled distal bowel. (orig.)

  16. Inflammatory Bowel Disease in Primary Immunodeficiencies.

    Science.gov (United States)

    Kelsen, Judith R; Sullivan, Kathleen E

    2017-08-01

    Inflammatory bowel disease is most often a polygenic disorder with contributions from the intestinal microbiome, defects in barrier function, and dysregulated host responses to microbial stimulation. There is, however, increasing recognition of single gene defects that underlie a subset of patients with inflammatory bowel disease, particularly those with early-onset disease, and this review focuses on the primary immunodeficiencies associated with early-onset inflammatory bowel disease. The advent of next-generation sequencing has led to an improved recognition of single gene defects underlying some cases of inflammatory bowel disease. Among single gene defects, immune response genes are the most frequent category identified. This is also true of common genetic variants associated with inflammatory bowel disease, supporting a pivotal role for host responses in the pathogenesis. This review focuses on practical aspects related to diagnosis and management of children with inflammatory bowel disease who have underlying primary immunodeficiencies.

  17. Optimal preparation-to-colonoscopy interval in split-dose PEG bowel preparation determines satisfactory bowel preparation quality: an observational prospective study.

    Science.gov (United States)

    Seo, Eun Hee; Kim, Tae Oh; Park, Min Jae; Joo, Hee Rin; Heo, Nae Yun; Park, Jongha; Park, Seung Ha; Yang, Sung Yeon; Moon, Young Soo

    2012-03-01

    Several factors influence bowel preparation quality. Recent studies have indicated that the time interval between bowel preparation and the start of colonoscopy is also important in determining bowel preparation quality. To evaluate the influence of the preparation-to-colonoscopy (PC) interval (the interval of time between the last polyethylene glycol dose ingestion and the start of the colonoscopy) on bowel preparation quality in the split-dose method for colonoscopy. Prospective observational study. University medical center. A total of 366 consecutive outpatients undergoing colonoscopy. Split-dose bowel preparation and colonoscopy. The quality of bowel preparation was assessed by using the Ottawa Bowel Preparation Scale according to the PC interval, and other factors that might influence bowel preparation quality were analyzed. Colonoscopies with a PC interval of 3 to 5 hours had the best bowel preparation quality score in the whole, right, mid, and rectosigmoid colon according to the Ottawa Bowel Preparation Scale. In multivariate analysis, the PC interval (odds ratio [OR] 1.85; 95% CI, 1.18-2.86), the amount of PEG ingested (OR 4.34; 95% CI, 1.08-16.66), and compliance with diet instructions (OR 2.22l 95% CI, 1.33-3.70) were significant contributors to satisfactory bowel preparation. Nonrandomized controlled, single-center trial. The optimal time interval between the last dose of the agent and the start of colonoscopy is one of the important factors to determine satisfactory bowel preparation quality in split-dose polyethylene glycol bowel preparation. Copyright © 2012 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  18. Rotating magnetic shallow water waves and instabilities in a sphere

    Science.gov (United States)

    Márquez-Artavia, X.; Jones, C. A.; Tobias, S. M.

    2017-07-01

    Waves in a thin layer on a rotating sphere are studied. The effect of a toroidal magnetic field is considered, using the shallow water ideal MHD equations. The work is motivated by suggestions that there is a stably stratified layer below the Earth's core mantle boundary, and the existence of stable layers in stellar tachoclines. With an azimuthal background field known as the Malkus field, ?, ? being the co-latitude, a non-diffusive instability is found with azimuthal wavenumber ?. A necessary condition for instability is that the Alfvén speed exceeds ? where ? is the rotation rate and ? the sphere radius. Magneto-inertial gravity waves propagating westward and eastward occur, and become equatorially trapped when the field is strong. Magneto-Kelvin waves propagate eastward at low field strength, but a new westward propagating Kelvin wave is found when the field is strong. Fast magnetic Rossby waves travel westward, whilst the slow magnetic Rossby waves generally travel eastward, except for some ? modes at large field strength. An exceptional very slow westward ? magnetic Rossby wave mode occurs at all field strengths. The current-driven instability occurs for ? when the slow and fast magnetic Rossby waves interact. With strong field the magnetic Rossby waves become trapped at the pole. An asymptotic analysis giving the wave speed and wave form in terms of elementary functions is possible both in polar trapped and equatorially trapped cases.

  19. MRI for chronic inflammatory bowel disease

    International Nuclear Information System (INIS)

    Hansmann, H.J.; Hess, T.; Hahmann, M.; Erb, G.; Richter, G.M.; Duex, M.; Elsing, C.

    2001-01-01

    Chronic inflammatory bowel disease is diagnosed and monitored by the combination of colonoscopy and small bowel enteroklysis. Magnetic resonance imaging has become the gold standard for the imaging of perirectal and pelvic fistulas. With the advent of ultrafast MRI small and large bowel imaging has become highly attractive and is being advocated more and more in the diagnostic work up of inflammatory bowel disease. Imaging protocols include fast T 1 -weighted gradient echo and T 2 -weighted TSE sequences and oral or rectal bowel distension. Furthermore, dedicated imaging protocols are based on breath-hold imaging under pharmacological bowel paralysis and gastrointestinal MR contrast agents (Hydro-MRI). High diagnostic accuracy can be achieved in Crohn's disease with special reference to the pattern of disease, depth of inflammation, mesenteric reaction, sinus tract depiction and formation of abscess. In ulcerative colitis, the mucosa-related inflammation causes significantly less bowel wall thickening compared to Crohn's disease. Therefore with MRI, the extent of inflammatory changes is always underestimated compared to colonoscopy. According to our experience in more than 200 patients as well as the results in other centers, Hydro-MRI possesses the potential to replace enteroklysis in the diagnosis of chronic inflammatory bowel disease and most of the follow-up colonoscopies in Crohn's disease. Further technical improvements in 3D imaging will allow interactive postprocessing of the MR data. (orig.) [de

  20. Primary malignant small bowel tumor

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Kyung Seung; Suh, Ho Jong; Kim, So Sun; Kim, Ho Joon; Chun, Byung Hee; Joh, Young Duk [Kosin College, Pusan (Korea, Republic of)

    1990-07-15

    Small bowel tumors are rarely detected unless there is intestinal obstruction or bleeding. In the seven years 1982-1988, at Kosin Medical Center, 25 primary malignant small bowel tumors were studied radiographically with barium and / or computed tomography (CT). CT revealed gastrointestinal abnormalities in 20 patients. In ten, lesion were identified by upper G-I series, in 15 by small bowel series, and in addition, in 3 by colon enema. The most common malignant small bowel tumor was adenocarcinoma (N=15) and was next common lymphoma (N=7). On barium study, primary adenocarcinoma appeared as an irregular stricture (66.7%) and polypoid mass with intussusception was most prominent finding in lymphoma. Leiomyosarcoma appeared as an exophytic mass with excavation or ulceration. CT was found to be accurate in detecting wall thickening, complications and other associated findings. In conclusion, barium study was useful in the diagnosis of primary malignant small bowel tumor and CT was more accurate in detecting secondary findings.

  1. Primary malignant small bowel tumor

    International Nuclear Information System (INIS)

    Oh, Kyung Seung; Suh, Ho Jong; Kim, So Sun; Kim, Ho Joon; Chun, Byung Hee; Joh, Young Duk

    1990-01-01

    Small bowel tumors are rarely detected unless there is intestinal obstruction or bleeding. In the seven years 1982-1988, at Kosin Medical Center, 25 primary malignant small bowel tumors were studied radiographically with barium and / or computed tomography (CT). CT revealed gastrointestinal abnormalities in 20 patients. In ten, lesion were identified by upper G-I series, in 15 by small bowel series, and in addition, in 3 by colon enema. The most common malignant small bowel tumor was adenocarcinoma (N=15) and was next common lymphoma (N=7). On barium study, primary adenocarcinoma appeared as an irregular stricture (66.7%) and polypoid mass with intussusception was most prominent finding in lymphoma. Leiomyosarcoma appeared as an exophytic mass with excavation or ulceration. CT was found to be accurate in detecting wall thickening, complications and other associated findings. In conclusion, barium study was useful in the diagnosis of primary malignant small bowel tumor and CT was more accurate in detecting secondary findings

  2. The Potential of/for 'Slow': Slow Tourists and Slow Destinations

    Directory of Open Access Journals (Sweden)

    J. Guiver

    2016-05-01

    Full Text Available Slow tourism practices are nothing new; in fact, they were once the norm and still are for millions of people whose annual holiday is spent camping, staying in caravans, rented accommodation, with friends and relations or perhaps in a second home, who immerse themselves in their holiday environment, eat local food, drink local wine and walk or cycle around the area. So why a special edition about slow tourism? Like many aspects of life once considered normal (such as organic farming or free-range eggs, the emergence of new practices has highlighted differences and prompted a re-evaluation of once accepted practices and values. In this way, the concept of ‘slow tourism’ has recently appeared as a type of tourism that contrasts with many contemporary mainstream tourism practices. It has also been associated with similar trends already ‘branded’ slow: slow food and cittaslow (slow towns and concepts such as mindfulness, savouring and well-being.

  3. Functional bowel disease

    DEFF Research Database (Denmark)

    Rumessen, J J; Gudmand-Høyer, E

    1988-01-01

    Twenty-five patients with functional bowel disease were given fructose, sorbitol, fructose-sorbitol mixtures, and sucrose. The occurrence of malabsorption was evaluated by means of hydrogen breath tests and the gastrointestinal symptoms, if any, were recorded. One patient could not be evaluated...... because of lack of H2 production. Based on a cut-off level of 10 ppm rise of H2 concentration, malabsorption was apparent in 13 patients, in 7 of which the calculated absorption capacities were below 15 g. In contrast, in patients given 50 g of sucrose, malabsorption could not be detected. Ingestion...... with functional bowel disease. The findings may have direct influence on the dietary guidance given to a major group of patients with functional bowel disease and may make it possible to define separate entities in this disease complex....

  4. Bowel Endometriosis Syndrome

    DEFF Research Database (Denmark)

    Riiskjær, M; Egekvist, A G; Hartwell, D

    2017-01-01

    STUDY QUESTION: Is it possible to develop a validated score that can identify women with Bowel Endometriosis Syndrome (BENS) and be used to monitor the effect of medical and surgical treatment? SUMMARY ANSWER: The BENS score can be used to identify women with BENS and to monitor the effect...... of medical and surgical treatment of women suffering from bowel endometriosis. WHAT IS KNOWN ALREADY: Endometriosis is a heterogeneous disease with extensive variation in anatomical and clinical presentation, and symptoms do not always correspond to the disease burden. Current endometriosis scoring systems...... are mainly based on anatomical and surgical findings. STUDY DESIGN, SIZE, DURATION: The score was developed and validated from a cohort of 525 women with medically or surgically treated bowel endometriosis from Aarhus and Copenhagen University Hospitals, Denmark. PARTICIPANTS/MATERIALS, SETTING AND METHODS...

  5. Effect of weak nonlinearities on the plane waves in a plasma stream

    International Nuclear Information System (INIS)

    Seshadri, S.R.

    1976-01-01

    The effect of weak nonlinearities on the monochromatic plane waves in a cold infinite plasma stream is investigated for the case in which the waves are progressing parallel to the drift velocity. The fast and the slow space-charge waves undergo amplitude-dependent frequency and wave number shifts. There is a long time slow modulation of the amplitude of the electromagnetic mode which becomes unstable to this nonlinear wave modulation. The importance of using the relativistically correct equation of motion for predicting correctly the modulational stability of the electromagnetic mode is pointed out. (author)

  6. Lamb wave propagation in monocrystalline silicon wafers.

    Science.gov (United States)

    Fromme, Paul; Pizzolato, Marco; Robyr, Jean-Luc; Masserey, Bernard

    2018-01-01

    Monocrystalline silicon wafers are widely used in the photovoltaic industry for solar panels with high conversion efficiency. Guided ultrasonic waves offer the potential to efficiently detect micro-cracks in the thin wafers. Previous studies of ultrasonic wave propagation in silicon focused on effects of material anisotropy on bulk ultrasonic waves, but the dependence of the wave propagation characteristics on the material anisotropy is not well understood for Lamb waves. The phase slowness and beam skewing of the two fundamental Lamb wave modes A 0 and S 0 were investigated. Experimental measurements using contact wedge transducer excitation and laser measurement were conducted. Good agreement was found between the theoretically calculated angular dependency of the phase slowness and measurements for different propagation directions relative to the crystal orientation. Significant wave skew and beam widening was observed experimentally due to the anisotropy, especially for the S 0 mode. Explicit finite element simulations were conducted to visualize and quantify the guided wave beam skew. Good agreement was found for the A 0 mode, but a systematic discrepancy was observed for the S 0 mode. These effects need to be considered for the non-destructive testing of wafers using guided waves.

  7. Study of equatorial Kelvin waves using the MST radar and radiosonde observations

    Directory of Open Access Journals (Sweden)

    P. Kishore

    2005-06-01

    Full Text Available In this paper an attempt has been made to study equatorial Kelvin waves using a high power coherent VHF radar located at Gadanki (13.5° N, 79.2° E, a tropical station in the Indian sub-continent. Simultaneous radiosonde observations taken from a nearby meteorological station located in Chennai (13.04° N, 80.17° E were also used to see the coherence in the observed structures. These data sets were analyzed to study the mean winds and equatorial waves in the troposphere and lower stratosphere. Equatorial waves with different periodicities were identified. In the present study, particular attention has been given to the fast Kelvin wave (6.5-day and slow Kelvin wave (16-day. Mean zonal wind structures were similar at both locations. The fast Kelvin wave amplitudes were somewhat similar in both observations and the maximum amplitude is about 8m/s. The phase profiles indicated a slow downward progression. The slow Kelvin wave (16-day amplitudes shown by the radiosonde measurements are a little larger than the radar derived amplitudes. The phase profiles showed downward phase progression and it translates into a vertical wavelength of ~10-12km. The radar and radiosonde derived amplitudes of fast and slow Kelvin waves are larger at altitudes near the tropopause (15-17km, where the mean wind attains westward maximum.

  8. Cardiovascular and respiratory changes during slow-wave sleep in rats are associated with electrocorticogram desynchronization

    Directory of Open Access Journals (Sweden)

    J.R. Dias-dos-Santos

    1997-11-01

    Full Text Available In awake rats a single recurrent larger tidal volume (deep breaths occurs at regular intervals, followed by oscillations in arterial pressure and heart rate. In the present study we recorded the changes in blood pressure, heart rate and ventilation during the wakefulness-sleep cycle identified by electrocorticographic records in order to determine whether the deep breaths and cardiovascular oscillations were associated with changes in the electrocorticogram. During several episodes of slow-wave sleep (SWS in 7 rats the deep breaths and oscillations in arterial pressure and heart rate were preceded by SWS desynchronization. The interval between deep breaths during SWS was 71 ± 4 s, the period between initial desynchronization and the generation of deep breaths was 3.98 ± 0.45 s and the duration of SWS desynchronization was 11 ± 0.65 s. Hypotension (-16 ± 1 mmHg and tachycardia (+15 ± 5 bpm were observed during deep breaths in the SWS state. These data indicate that the oscillations in arterial pressure and heart rate during SWS are associated with deep breaths, which in turn are preceded by desynchronization of the electrocorticogram in this state of sleep

  9. Broad self-trapped and slow light bands based on negative refraction and interference of magnetic coupled modes

    International Nuclear Information System (INIS)

    Fang, Yun-tuan; Ni, Zhi-yao; Zhu, Na; Zhou, Jun

    2016-01-01

    We propose a new mechanism to achieve light localization and slow light. Through the study on the coupling of two magnetic surface modes, we find a special convex band that takes on a negative refraction effect. The negative refraction results in an energy flow concellation effect from two degenerated modes on the convex band. The energy flow concellation effect leads to forming of the self-trapped and slow light bands. In the self-trapped band light is localized around the source without reflection wall in the waveguide direction, whereas in the slow light band, light becomes the standing-waves and moving standing-waves at the center and the two sides of the waveguide, respectively. (paper)

  10. Broad self-trapped and slow light bands based on negative refraction and interference of magnetic coupled modes.

    Science.gov (United States)

    Fang, Yun-Tuan; Ni, Zhi-Yao; Zhu, Na; Zhou, Jun

    2016-01-13

    We propose a new mechanism to achieve light localization and slow light. Through the study on the coupling of two magnetic surface modes, we find a special convex band that takes on a negative refraction effect. The negative refraction results in an energy flow concellation effect from two degenerated modes on the convex band. The energy flow concellation effect leads to forming of the self-trapped and slow light bands. In the self-trapped band light is localized around the source without reflection wall in the waveguide direction, whereas in the slow light band, light becomes the standing-waves and moving standing-waves at the center and the two sides of the waveguide, respectively.

  11. Slow and fast light in semiconductor waveguides

    DEFF Research Database (Denmark)

    Mørk, Jesper; Hansen, Per Lunnemann; Xue, Weiqi

    2010-01-01

    Investigations of slow and fast light effects in semiconductor waveguides entail interesting physics and point to a number of promising applications. In this review we give an overview of recent progress in the field, in particular focusing on the physical mechanisms of electromagnetically induced...... transparency and coherent population oscillations. While electromagnetically induced transparency has been the most important effect in realizing slowdown effects in atomic gasses, progress has been comparatively slow in semiconductors due to inherent problems of fast dephasing times and inhomogeneous...... broadening in quantum dots. The physics of electromagnetically induced transparency in semiconductors is discussed, emphasizing these limitations and recent suggestions for overcoming them. On the other hand, the mechanism of coherent population oscillations relies on wave mixing effects and is well suited...

  12. Association between pain episodes and high amplitude propagated pressure waves in patients with irritable bowel syndrome

    NARCIS (Netherlands)

    Clemens, C. H. M.; Samsom, M.; Roelofs, J. M. M.; van Berge Henegouwen, G. P.; Smout, A. J. P. M.

    2003-01-01

    OBJECTIVES: In the pathogenesis of irritable bowel syndrome (IBS), both increased visceral sensitivity and altered colonic motility seem to play a role. The aim of this study was to quantify the temporal relationship between pain episodes and the occurrence of high amplitude propagated pressure

  13. MRI of the small bowel: can sufficient bowel distension be achieved with small volumes of oral contrast?

    International Nuclear Information System (INIS)

    Kinner, Sonja; Kuehle, Christiane A.; Ladd, Susanne C.; Barkhausen, Joerg; Herbig, Sebastian; Haag, Sebastian; Lauenstein, Thomas C.

    2008-01-01

    Sufficient luminal distension is mandatory for small bowel imaging. However, patients often are unable to ingest volumes of currently applied oral contrast compounds. The aim of this study was to evaluate if administration of low doses of an oral contrast agent with high-osmolarity leads to sufficient and diagnostic bowel distension. Six healthy volunteers ingested at different occasions 150, 300 and 450 ml of a commercially available oral contrast agent (Banana Smoothie Readi-Cat, E-Z-EM; 194 mOsmol/l). Two-dimensional TrueFISP data sets were acquired in 5-min intervals up to 45 min after contrast ingestion. Small bowel distension was quantified using a visual five-grade ranking (5 very good distension, 1 = collapsed bowel). Results were statistically compared using a Wilcoxon-Rank test. Ingestion of 450 ml and 300 ml resulted in a significantly better distension than 150 ml. The all-over average distension value for 450 ml amounted to 3.4 (300 ml: 3.0, 150 ml: 2.3) and diagnostic bowel distension could be found throughout the small intestine. Even 45 min after ingestion of 450 ml the jejunum and ileum could be reliably analyzed. Small bowel imaging with low doses of contrast leads to diagnostic distension values in healthy subjects when a high-osmolarity substance is applied. These findings may help to further refine small bowel MRI techniques, but need to be confirmed in patients with small bowel disorders. (orig.)

  14. Clinical peculiarities of antibiotic associated bowels impairment and its significance in irritable bowel syndrome appearance

    Directory of Open Access Journals (Sweden)

    І. O. Pasichna

    2016-06-01

    Full Text Available Aim: the main objective of this study was to investigate bowels impairment due to treatment with antibiotics, its incidence and clinical peculiarities; to evaluate its role in appearance of in irritable bowel syndrome. Material and Methods. We studied 110 patients (33 males and 77 females, age range 16-83 years, who received treatment with antibiotic. We evaluated the function of the intestine before treatment with antibiotic, then in 1 week, 3 months after treatment finish (1, 2, 3, 4 visits respectively. Control group included 20 healthy persons, who haven't had antibiotics administered during recent two years. Results. We revealed that the signs of bowel function impairment took place at the first visit in 18.2% of patients, at the second visit – in 60.0% of patients, at the third visit – in 45.5% of patients and at the fourth visit – in 41.1% of patients. At the second, third and fourth visits the signs of bowels function impairment were observed reliably more often then at the first visit (before antibiotic administration, p<0.001. At the second visit the signs bowels function disorders were the most prominent: abdominal pain – in 44.5%, distention – in 46.4%, diarrhea – in 29.1%, constipation – in 18.2%, presence of both (diarrhea and periodically constipation manifestations – in 2.7%; and extraintestinal manifestations (depression. depressed mood, sorrow, apathy, decreased stamina, sleep disturbances – in 29.1% of patients. Clinical manifestations of irritable bowel syndrome occured in 6 months of observation in 32.2% of patients. Conclusions. The signs of bowel function impairment were observed in 60.0% of patients after finishing treatment with antibiotic. This incidence is much higher than in control group (р<0.001. Bowel disorders mostly manifested as the changes in quantity and consistency of feaces, pain, abdominal distention and extraintestinal manifestations. In 32.2% of patients clinical manifestations of

  15. Nutritive support in short Bowel syndrome (sbs

    Directory of Open Access Journals (Sweden)

    Simić Dušica

    2003-01-01

    Full Text Available Short bowel syndrome most commonly result after bowel resection for necrosis of the bowel. It may be caused by arterial or venous thrombosis, volvolus and in children, necrotizing enterocolitis. The other causes are Crohn,s disease intestinal atresia. The factors influencing the risk on short bowel syndrome are the remaining length of the small bowel, the age of onset, the length of the colon, the presence or absence of the ileo-coecal valve and the time after resection. Besides nutritional deficiencies there some other consequences of extensive resections of the small intestine (gastric acid hypersecretion, d-lactic acidosis, nephrolithiasis, cholelithiasis, which must be diagnosed, treated, and if possible, prevented. With current therapy most patients with short bowel have normal body mass index and good quality of life.

  16. Neonatal thalamic hemorrhage is strongly associated with electrical status epilepticus in slow wave sleep.

    Science.gov (United States)

    Kersbergen, Karina J; de Vries, Linda S; Leijten, Frans S S; Braun, Kees P J; Nievelstein, Rutger A J; Groenendaal, Floris; Benders, Manon J N L; Jansen, Floor E

    2013-04-01

    Thalamic hemorrhage has been associated with neonatal cerebral sinovenous thrombosis (CSVT), especially when the straight sinus is involved, and often presents with neonatal seizures. Early thalamic injury has previously been shown to predispose to epilepsy and electrical status epilepticus in slow wave sleep (ESES). The objective of this study was to assess the prevalence of sleep-induced epileptic electroencephalography (EEG) abnormalities and postneonatal epilepsy after neonatal thalamic hemorrhage associated with CSVT, in the absence of more widespread cerebral damage. Between 2003 and 2008 15 neonates were diagnosed with a thalamic hemorrhage due to suspected or proven CSVT. Neurodevelopment and the history of seizures were assessed at follow-up in the outpatient clinic in all 14 survivors (age 2-9 years). Whole-night or sleep-deprived EEG recordings were obtained to assess the prevalence of interictal epileptiform activity (EA) and calculate a sleep-induced spike and wave index (SWI). Three children were diagnosed with classic ESES (SWI >85%). Two children had ESES spectrum disorder (SWI between 50% and 85%), and in two children significant sleep-induced epileptiform activity (SIEA) was noted (SWI between 25% and 50%). Two other children were diagnosed with focal epilepsy, in the absence of sleep-induced epileptiform EEG abnormalities. Five children (age 2-7 years) had normal EEG recordings at follow-up. Deficits in neurodevelopment were seen significantly more often in children with ESES, ESES spectrum, or SIEA. Neonates with thalamic hemorrhage associated with straight sinus thrombosis, without evidence of more widespread cerebral damage, are at high risk of developing ESES (spectrum) disorder (35%), SIEA (14%), or focal epilepsy (14%). Electrographic abnormalities may already be present prior to recognition of cognitive deficits. Early diagnosis may guide parents and caregivers, and subsequent treatment may improve neurodevelopmental outcome. Routine

  17. What drives slow wave activity during early non-REM sleep: Learning during prior wake or effort?

    Directory of Open Access Journals (Sweden)

    Ziyang Li

    Full Text Available What is the function of sleep in humans? One claim is that sleep consolidates learning. Slow wave activity (SWA, i.e. slow oscillations of frequency < 4 Hz, has been observed in electroencephalograms (EEG during sleep; it increases with prior wakefulness and decreases with sleep. Studies have claimed that increase in SWA in specific regions of the sleeping brain is correlated with overnight improved performance, i.e. overnight consolidation, on a demanding motor learning task. We wondered if SWA change during sleep is attributable to overnight consolidation or to metabolic demand. Participants executed out-and-back movements to a target using a pen-like cursor with their dominant hand while the target and cursor position were displayed on a screen. They trained on three different conditions on separate nights, differing in the amount and degree of rotation between the actual hand movement direction and displayed cursor movement direction. In the no-rotation (NR condition, there was no rotation. In the single rotation (SR condition, the amount of rotation remained the same throughout, and performance improved both across pre-sleep training and after sleep, i.e. overnight consolidation occurred; in the random rotation (RR condition, the amount of rotation varied randomly from trial to trial, and no overnight consolidation occurred; SR and RR were cognitively demanding. The average EEG power density of SWA for the first 30 min. of non-rapid eye movement sleep after training was computed. Both SR and RR elicited increase in SWA in the parietal region; furthermore, the topographic distribution of SWA in each was remarkably similar. No correlation was found between the overnight performance improvement on SR and the SWA change in the parietal region on measures of learning. Our results argue that regulation of SWA in early sleep is associated with high levels of cognitive effort during prior wakefulness, and not just overnight consolidation.

  18. The properties of fast and slow oblique solitons in a magnetized plasma

    Science.gov (United States)

    McKenzie, J. F.; Doyle, T. B.

    2002-01-01

    This work builds on a recent treatment by McKenzie and Doyle [Phys. Plasmas 8, 4367 (2001)], on oblique solitons in a cold magnetized plasma, to include the effects of plasma thermal pressure. Conservation of total momentum in the direction of wave propagation immediately shows that if the flow is supersonic, compressive (rarefactive) changes in the magnetic pressure induce decelerations (accelerations) in the flow speed, whereas if the flow is subsonic, compressive (rarefactive) changes in the magnetic pressure induce accelerations (decelerations) in the flow speed. Such behavior is characteristic of a Bernoulli-type plasma momentum flux which exhibits a minimum at the plasma sonic point. The plasma energy flux (kinetic plus enthalpy) also shows similar Bernoulli-type behavior. This transonic effect is manifest in the spatial structure equation for the flow speed (in the direction of propagation) which shows that soliton structures may exist if the wave speed lies either (i) in the range between the fast and Alfven speeds or (ii) between the sound and slow mode speed. These conditions follow from the requirement that a defined, characteristic "soliton parameter" m exceeds unity. It is in this latter slow soliton regime that the effects of plasma pressure are most keenly felt. The equilibrium points of the structure equation define the center of the wave. The structure of both fast and slow solitons is elucidated through the properties of the energy integral function of the structure equation. In particular, the slow soliton, which owes its existence to plasma pressure, may have either a compressive or rarefactive nature, and exhibits a rich structure, which is revealed through the spatial structure of the longitudinal speed and its corresponding transverse velocity hodograph.

  19. The properties of fast and slow oblique solitons in a magnetized plasma

    International Nuclear Information System (INIS)

    McKenzie, J.F.; Doyle, T.B.

    2002-01-01

    This work builds on a recent treatment by McKenzie and Doyle [Phys. Plasmas 8, 4367 (2001)], on oblique solitons in a cold magnetized plasma, to include the effects of plasma thermal pressure. Conservation of total momentum in the direction of wave propagation immediately shows that if the flow is supersonic, compressive (rarefactive) changes in the magnetic pressure induce decelerations (accelerations) in the flow speed, whereas if the flow is subsonic, compressive (rarefactive) changes in the magnetic pressure induce accelerations (decelerations) in the flow speed. Such behavior is characteristic of a Bernoulli-type plasma momentum flux which exhibits a minimum at the plasma sonic point. The plasma energy flux (kinetic plus enthalpy) also shows similar Bernoulli-type behavior. This transonic effect is manifest in the spatial structure equation for the flow speed (in the direction of propagation) which shows that soliton structures may exist if the wave speed lies either (i) in the range between the fast and Alfven speeds or (ii) between the sound and slow mode speed. These conditions follow from the requirement that a defined, characteristic 'soliton parameter' m exceeds unity. It is in this latter slow soliton regime that the effects of plasma pressure are most keenly felt. The equilibrium points of the structure equation define the center of the wave. The structure of both fast and slow solitons is elucidated through the properties of the energy integral function of the structure equation. In particular, the slow soliton, which owes its existence to plasma pressure, may have either a compressive or rarefactive nature, and exhibits a rich structure, which is revealed through the spatial structure of the longitudinal speed and its corresponding transverse velocity hodograph

  20. Volvulus of the Small Bowel and Colon

    Science.gov (United States)

    Kapadia, Muneera R.

    2017-01-01

    Volvulus of the intestines may involve either the small bowel or colon. In the pediatric population, small bowel volvulus is more common, while in the adult population, colonic volvulus is more often seen. The two most common types of colonic volvulus include sigmoid and cecal volvulus. Prompt diagnosis and treatment is imperative, otherwise bowel ischemia may ensue. Treatment often involves emergent surgical exploration and bowel resection. PMID:28144211

  1. Coronal Waves and Oscillations

    Directory of Open Access Journals (Sweden)

    Nakariakov Valery M.

    2005-07-01

    Full Text Available Wave and oscillatory activity of the solar corona is confidently observed with modern imaging and spectral instruments in the visible light, EUV, X-ray and radio bands, and interpreted in terms of magnetohydrodynamic (MHD wave theory. The review reflects the current trends in the observational study of coronal waves and oscillations (standing kink, sausage and longitudinal modes, propagating slow waves and fast wave trains, the search for torsional waves, theoretical modelling of interaction of MHD waves with plasma structures, and implementation of the theoretical results for the mode identification. Also the use of MHD waves for remote diagnostics of coronal plasma - MHD coronal seismology - is discussed and the applicability of this method for the estimation of coronal magnetic field, transport coefficients, fine structuring and heating function is demonstrated.

  2. Lamb wave propagation in monocrystalline silicon wafers

    OpenAIRE

    Fromme, P.; Pizzolato, M.; Robyr, J-L; Masserey, B.

    2018-01-01

    Monocrystalline silicon wafers are widely used in the photovoltaic industry for solar panels with high conversion efficiency. Guided ultrasonic waves offer the potential to efficiently detect micro-cracks in the thin wafers. Previous studies of ultrasonic wave propagation in silicon focused on effects of material anisotropy on bulk ultrasonic waves, but the dependence of the wave propagation characteristics on the material anisotropy is not well understood for Lamb waves. The phase slowness a...

  3. Small bowel volvulus in children

    International Nuclear Information System (INIS)

    Siegel, M.J.; Shackelford, G.D.; McAlister, W.H.

    1980-01-01

    Two children with small bowel volvulus diagnosed on barium enema examination are reported. In one patient the volvulus was associated with malrotation and in the other patient there was a post-operative peritoneal adhesion. In both cases the diagnosis was based on beaking of the head of the barium column at the site of volvulus. Radiographic demonstration of a beak sign in the small bowel on barium enema examination should suggest a diagnosis of small bowel volvulus, and indicates the need for immediate surgery. (orig.) [de

  4. Physiologic effects of bowel preparation

    DEFF Research Database (Denmark)

    Holte, Kathrine; Nielsen, Kristine Grubbe; Madsen, Jan Lysgård

    2004-01-01

    healthy volunteers (median age, 63 years) underwent bowel preparation with bisacodyl and sodium phosphate. Fluid and food intake were standardized according to weight, providing adequate calorie and oral fluid intake. Before and after bowel preparation, weight, exercise capacity, orthostatic tolerance...

  5. Double shock front formation in cylindrical radiative blast waves produced by laser irradiation of krypton gas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I.; Quevedo, H. J.; Feldman, S.; Bang, W.; Serratto, K.; McCormick, M.; Aymond, F.; Dyer, G.; Bernstein, A. C.; Ditmire, T. [Center for High Energy Density Science, Department of Physics, The University of Texas at Austin, C1510, Austin, Texas 78712 (United States)

    2013-12-15

    Radiative blast waves were created by irradiating a krypton cluster source from a supersonic jet with a high intensity femtosecond laser pulse. It was found that the radiation from the shock surface is absorbed in the optically thick upstream medium creating a radiative heat wave that travels supersonically ahead of the main shock. As the blast wave propagates into the heated medium, it slows and loses energy, and the radiative heat wave also slows down. When the radiative heat wave slows down to the transonic regime, a secondary shock in the ionization precursor is produced. This paper presents experimental data characterizing both the initial and secondary shocks and numerical simulations to analyze the double-shock dynamics.

  6. Bowel Diseases and Kidneys

    Directory of Open Access Journals (Sweden)

    A.E. Dorofeiev

    2015-09-01

    Full Text Available This review of contemporary publications analyzes the prevalence of combinations of bowel and renal diseases. Special attention is paid to the problem of correlation between bowel diseases and urolithiasis. We consider the possible pathogenic mechanisms of lesions, such as genetically determined violations of intestinal absorption and secretion, changes in the intestinal microbiota, systemic inflammatory response, water and electrolyte disturbances.

  7. The theory of magnetohydrodynamic wave generation by localized sources. I - General asymptotic theory

    Science.gov (United States)

    Collins, William

    1989-01-01

    The magnetohydrodynamic wave emission from several localized, periodic, kinematically specified fluid velocity fields are calculated using Lighthill's method for finding the far-field wave forms. The waves propagate through an isothermal and uniform plasma with a constant B field. General properties of the energy flux are illustrated with models of pulsating flux tubes and convective rolls. Interference theory from geometrical optics is used to find the direction of minimum fast-wave emission from multipole sources and slow-wave emission from discontinuous sources. The distribution of total flux in fast and slow waves varies with the ratios of the source dimensions l to the acoustic and Alfven wavelengths.

  8. Physiologic effects of bowel preparation

    DEFF Research Database (Denmark)

    Holte, Kathrine; Nielsen, Kristine Grubbe; Madsen, Jan Lysgård

    2004-01-01

    PURPOSE: Despite the universal use of bowel preparation before colonoscopy and colorectal surgery, the physiologic effects have not been described in a standardized setting. This study was designed to investigate the physiologic effects of bowel preparation. METHODS: In a prospective study, 12...

  9. Imaging differentiation of phytobezoar and small-bowel faeces: CT characteristics with quantitative analysis in patients with small- bowel obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ya-Cheng; Liu, Chang-Hsien; Hsu, Hsian-He; Yu, Chih-Yung [Tri-Service General Hospital, National Defense Medical Center, Department of Radiology, Taipei (China); Wang, Hong-Hau [Tri-Service General Hospital, National Defense Medical Center, Department of Radiology, Taipei (China); Tri-Service General Hospital Songshan Branch, National Defense Medical Center, Department of Radiology, Taipei (China); Fan, Hsiu-Lung [Tri-Service General Hospital, National Defense Medical Center, Division of General Surgery, Department of Surgery, Taipei (China); Chen, Ran-Chou [Taipei City Hospital, Department of Radiology, Taipei (China); National Yang-Ming Univeristy, Department of Biochemical Imaging and Radiological Sciences, Taipei (China); Chang, Wei-Chou [Tri-Service General Hospital, National Defense Medical Center, Department of Radiology, Taipei (China); National Yang-Ming Univeristy, Department of Biochemical Imaging and Radiological Sciences, Taipei (China)

    2015-04-01

    The objective is to use multidetector computed tomography (MDCT) to differentiate phytobezoar impaction and small-bowel faeces in patients with small-bowel obstruction (SBO). We retrospectively reviewed 91 consecutive SBO patients with surgically proven phytobezoars (n = 31) or adhesion with small-bowel faeces (n = 60). Two readers blinded to the diagnosis recorded the following MDCT features: degree of obstruction, transition point, mesenteric fatty stranding, intraperitoneal fluid, air-fluid level, pneumatosis intestinalis, and portal venous gas. MDCT measurements of the food debris length, attenuation, luminal diameter, and wall thickness of the obstructed bowel were also compared. A higher grade of obstruction with an absence of mesenteric fatty stranding and intraperitoneal fluid was more commonly seen in the phytobezoar group than in the small-bowel faeces group (p < 0.01). The food debris length (phytobezoar, 5.7 ± 2.8 cm; small-bowel feces, 20.3 ± 7.9 cm, p < 0.01) and mean attenuation (phytobezoar, -59.6 ± 43.3 Hounsfield units (HU); small-bowel faeces, 8.5 ± 7.7 HU, p <0.01) were significantly different between the two groups. The ROC curve showed that food debris length <9.5 cm and mean attenuation value < -11.75 HU predicted phytobezoar impaction. MDCT features with measurements of the food debris length and mean attenuation assist the differentiation of phytobezoar impaction and small-bowel faeces. (orig.)

  10. Imaging differentiation of phytobezoar and small-bowel faeces: CT characteristics with quantitative analysis in patients with small- bowel obstruction

    International Nuclear Information System (INIS)

    Chen, Ya-Cheng; Liu, Chang-Hsien; Hsu, Hsian-He; Yu, Chih-Yung; Wang, Hong-Hau; Fan, Hsiu-Lung; Chen, Ran-Chou; Chang, Wei-Chou

    2015-01-01

    The objective is to use multidetector computed tomography (MDCT) to differentiate phytobezoar impaction and small-bowel faeces in patients with small-bowel obstruction (SBO). We retrospectively reviewed 91 consecutive SBO patients with surgically proven phytobezoars (n = 31) or adhesion with small-bowel faeces (n = 60). Two readers blinded to the diagnosis recorded the following MDCT features: degree of obstruction, transition point, mesenteric fatty stranding, intraperitoneal fluid, air-fluid level, pneumatosis intestinalis, and portal venous gas. MDCT measurements of the food debris length, attenuation, luminal diameter, and wall thickness of the obstructed bowel were also compared. A higher grade of obstruction with an absence of mesenteric fatty stranding and intraperitoneal fluid was more commonly seen in the phytobezoar group than in the small-bowel faeces group (p < 0.01). The food debris length (phytobezoar, 5.7 ± 2.8 cm; small-bowel feces, 20.3 ± 7.9 cm, p < 0.01) and mean attenuation (phytobezoar, -59.6 ± 43.3 Hounsfield units (HU); small-bowel faeces, 8.5 ± 7.7 HU, p <0.01) were significantly different between the two groups. The ROC curve showed that food debris length <9.5 cm and mean attenuation value < -11.75 HU predicted phytobezoar impaction. MDCT features with measurements of the food debris length and mean attenuation assist the differentiation of phytobezoar impaction and small-bowel faeces. (orig.)

  11. Oral contrast agents for small bowel distension in MRI: influence of the osmolarity for small bowel distention

    International Nuclear Information System (INIS)

    Ajaj, Waleed; Kuehle, Christiane; Nuefer, Michael; Goehde, Susanne C.; Lauenstein, Thomas C.; Goyen, Mathias; Schneemann, Hubert; Ruehm, Stefan G.

    2005-01-01

    To assess the effect of the osmolarity for small bowel distension in MRI, ten volunteers ingested at two separate occasions negative oral contrast agents with different quantity and osmolarity: (1) a water solution combined with 2.0% sorbitol and 0.2% locus bean gum (LBG) with a quantity of 1500 ml and an osmolarity of 148 mOsmol/l, (2) a water solution combined with 2.0% sorbitol and 2.0% barium sulphate with a quantity of 1000 ml and an osmolarity of 194 mOsmol/l. Small bowel distension was quantified on coronal 2D-TrueFISP images by measuring the small bowel diameters. There were no statistically significant differences in mean small bowel diameter between both contrast agents. The mean small bowel distension was 19.2 mm after ingestion of 1500 ml of sorbitol-LBG solution and 19.0 mm after ingestion of 1000-ml sorbitol-barium sulphate solution. Furthermore, all volunteers found the ingestion of 1000-ml solution more pleasant than the 1500-ml solution. The ingestion of 1000 ml of sorbitol-barium sulphate solution led to a sufficient small bowel distension compared to 1500 ml of sorbitol-LBG solution. The side effect rate of both solutions was low. Based on these data, we recommend a quantity of 1000 ml of sorbitol-barium sulphate solution as an alternative for 1500-ml sorbitol-LBG solution for optimal bowel distension. (orig.)

  12. ON THE ORIGIN OF THE SLOW SPEED SOLAR WIND: HELIUM ABUNDANCE VARIATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Rakowski, Cara E.; Laming, J. Martin [Space Science Division, Naval Research Laboratory Code 7674L, Washington, DC 20375 (United States)

    2012-07-20

    The first ionization potential (FIP) effect is the by now well-known enhancement in abundance over photospheric values of Fe and other elements with FIP below about 10 eV observed in the solar corona and slow speed solar wind. In our model, this fractionation is achieved by means of the ponderomotive force, arising as Alfven waves propagate through or reflect from steep density gradients in the solar chromosphere. This is also the region where low FIP elements are ionized, and high FIP elements are largely neutral leading to the fractionation as ions interact with the waves but neutrals do not. Helium, the element with the highest FIP and consequently the last to remain neutral as one moves upward, can be depleted in such models. Here, we investigate this depletion for varying loop lengths and magnetic field strengths. Variations in this depletion arise as the concentration of the ponderomotive force at the top of the chromosphere varies in response to Alfven wave frequency with respect to the resonant frequency of the overlying coronal loop, the magnetic field, and possibly also the loop length. We find that stronger depletions of He are obtained for weaker magnetic field, at frequencies close to or just above the loop resonance. These results may have relevance to observed variations of the slow wind solar He abundance with wind speed, with slower slow speed solar wind having a stronger depletion of He.

  13. Alfvén wave dynamics at the neighborhood of a 2.5D magnetic null-point

    Science.gov (United States)

    Sabri, S.; Vasheghani Farahani, S.; Ebadi, H.; Hosseinpour, M.; Fazel, Z.

    2018-05-01

    The aim of the present study is to highlight the energy transfer via the interaction of magnetohydrodynamic waves with a 2.5D magnetic null-point in a finite plasma-β regime of the solar corona. An initially symmetric Alfvén pulse at a specific distance from a magnetic null-point is kicked towards the isothermal null-point. A shock-capturing Godunov-type PLUTO code is used to solve the ideal magnetohydrodynamic set equations in the context of wave-plasma energy transfer. As the Alfvén wave propagates towards the magnetic null-point it experiences speed lowering which ends up in releasing energy along the separatrices. In this line owing to the Alfvén wave, a series of events take place that contribute towards coronal heating. Nonlinear induced waves are by products of the torsional Alfvén interaction with magnetic null-points. The energy of these induced waves which are fast magnetoacoustic (transverse) and slow magnetoacoustic (longitudinal) waves are supplied by the Alfvén wave. The nonlinearly induced density perturbations are proportional to the Alfvén wave energy loss. This supplies energy for the propagation of fast and slow magnetoacoustic waves, where in contrast to the fast wave the slow wave experiences a continuous energy increase. As such, the slow wave may transfer its energy to the medium at later times, maintaining a continuous heating mechanism at the neighborhood of a magnetic null-point.

  14. Matter-Wave Tractor Beams

    DEFF Research Database (Denmark)

    Gorlach, Alexey A.; Gorlach, Maxim A.; Lavrinenko, Andrei

    2017-01-01

    Optical and acoustic tractor beams are currently the focus of intense research due to their counterintuitive property of exerting a pulling force on small scattering objects. In this Letter we propose a matter-wave tractor beam and utilize the de Broglie waves of nonrelativistic matter particles...... are compared, and the matter-wave pulling force is found to have exclusive properties of dragging slow particles in short-range potentials. We envisage that the use of tractor beams could lead to the unprecedented precision in manipulation with atomic-scale quantum objects....

  15. Mucosa-associated Lymphoid Tissue Lymphoma Presenting with Bowel Obstruction of the Duodenum and Small Bowels: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Guen Ho; Hong, Seong Sook; Kim, Jung Hoon; Chang, Yun Woo; Choi, Duek Lin; Hwang, Jung Hwa; Kwon, Kui Hyang [Soonchunhyang University Hospital, Seoul (Korea, Republic of)

    2010-01-15

    The occurrence of primary duodenal mucosa associated lymphoid tissue (MALT) lymphoma is extremely rare, and more so is the obstruction of the duodenum for the MALT lymphoma. We describe the small bowel follow through and CT findings in an uncommon case of MALT lymphoma presenting with bowel obstruction of the 2nd portion of the duodenum and small bowels.

  16. Mucosa-associated Lymphoid Tissue Lymphoma Presenting with Bowel Obstruction of the Duodenum and Small Bowels: A Case Report

    International Nuclear Information System (INIS)

    Ryu, Guen Ho; Hong, Seong Sook; Kim, Jung Hoon; Chang, Yun Woo; Choi, Duek Lin; Hwang, Jung Hwa; Kwon, Kui Hyang

    2010-01-01

    The occurrence of primary duodenal mucosa associated lymphoid tissue (MALT) lymphoma is extremely rare, and more so is the obstruction of the duodenum for the MALT lymphoma. We describe the small bowel follow through and CT findings in an uncommon case of MALT lymphoma presenting with bowel obstruction of the 2nd portion of the duodenum and small bowels

  17. Irritable bowel syndrome: contemporary nutrition management strategies.

    Science.gov (United States)

    Mullin, Gerard E; Shepherd, Sue J; Chander Roland, Bani; Ireton-Jones, Carol; Matarese, Laura E

    2014-09-01

    Irritable bowel syndrome is a complex disorder whose pathophysiology involves alterations in the enteric microbiota, visceral hypersensitivity, gut immune/barrier function, hypothalamic-pituitary-adrenal axis regulation, neurotransmitters, stress response, psychological factors, and more. The importance of diet in the management of irritable bowel syndrome has taken center stage in recent times as the literature validates the relationship of certain foods with the provocation of symptoms. Likewise, a number of elimination dietary programs have been successful in alleviating irritable bowel syndrome symptoms. Knowledge of the dietary management strategies for irritable bowel syndrome will help guide nutritionists and healthcare practitioners to deliver optimal outcomes. This tutorial reviews the nutrition management strategies for irritable bowel syndrome. © 2014 American Society for Parenteral and Enteral Nutrition.

  18. Linear theory of plasma filled backward wave oscillator

    Indian Academy of Sciences (India)

    An analytical and numerical study of backward wave oscillator (BWO) in linear regime is presented to get an insight into the excitation of electromagnetic waves as a result of the interaction of the relativistic electron beam with a slow wave structure. The effect of background plasma on the BWO instability is also presented.

  19. Reflections of hunger and satiation in the structure of temporal organization of slow electrical and spike activities of fundal and antral stomach muscles in rabbits.

    Science.gov (United States)

    Kromin, A A; Zenina, O Yu

    2012-11-01

    Manifestations of hunger and satiation in myoelectric activity patterns in different portions of the stomach were studied in chronic experiments. The state of hunger manifested in the structure of temporal organization of slow electric activity of muscles in the stomach body and antrum in the form of bimodal distributions of slow electric wave periods, while satiation as unimodal distribution. In hunger-specific bimodal distribution of slow electric wave periods generated by muscles of the stomach body and antrum, the position of the first maximum carries the information about oncoming food reinforcement, since this particular range of slow wave fluctuations determines temporal parameters of slow electric activity of muscles in all stomach regions in the course of subsequent successive food-procuring behavior. Under conditions of hunger, the pacemaker features of muscles in the lesser curvature are realized incompletely. Complete realization is achieved in the course of food intake and at the state of satiation.

  20. An immunoglobulin G-4 related sclerosing disease of the small bowel: CT and small bowel series findings

    International Nuclear Information System (INIS)

    Ko, Young Hwan; Hwang, Dae Hyun; Min, Seon Jeong; Woo, Ji Young; Kim, Jeong Won; Hong, Hye Sook; Yang, Ik; Lee, Yul

    2013-01-01

    Immunoglobulin G4 (IgG4)-related sclerosing disease is rare and is known to involve various organs. We present a case of histologically proven IgG4-related sclerosing disease of the small bowel with imaging findings on computed tomography (CT) and small bowel series. CT showed irregular wall thickening, loss of mural stratification and aneurysmal dilatation of the distal ileum. Small bowel series showed aneurysmal dilatations, interloop adhesion with traction and abrupt angulation.

  1. Observations of apparent superslow wave propagation in solar prominences

    Science.gov (United States)

    Raes, J. O.; Van Doorsselaere, T.; Baes, M.; Wright, A. N.

    2017-06-01

    Context. Phase mixing of standing continuum Alfvén waves and/or continuum slow waves in atmospheric magnetic structures such as coronal arcades can create the apparent effect of a wave propagating across the magnetic field. Aims: We observe a prominence with SDO/AIA on 2015 March 15 and find the presence of oscillatory motion. We aim to demonstrate that interpreting this motion as a magneto hydrodynamic (MHD) wave is faulty. We also connect the decrease of the apparent velocity over time with the phase mixing process, which depends on the curvature of the magnetic field lines. Methods: By measuring the displacement of the prominence at different heights to calculate the apparent velocity, we show that the propagation slows down over time, in accordance with the theoretical work of Kaneko et al. We also show that this propagation speed drops below what is to be expected for even slow MHD waves for those circumstances. We use a modified Kippenhahn-Schlüter prominence model to calculate the curvature of the magnetic field and fit our observations accordingly. Results: Measuring three of the apparent waves, we get apparent velocities of 14, 8, and 4 km s-1. Fitting a simple model for the magnetic field configuration, we obtain that the filament is located 103 Mm below the magnetic centre. We also obtain that the scale of the magnetic field strength in the vertical direction plays no role in the concept of apparent superslow waves and that the moment of excitation of the waves happened roughly one oscillation period before the end of the eruption that excited the oscillation. Conclusions: Some of the observed phase velocities are lower than expected for slow modes for the circumstances, showing that they rather fit with the concept of apparent superslow propagation. A fit with our magnetic field model allows for inferring the magnetic geometry of the prominence. The movie attached to Fig. 1 is available at http://www.aanda.org

  2. Globalisation of inflammatory bowel disease: perspectives from the evolution of inflammatory bowel disease in the UK and China.

    Science.gov (United States)

    Kaplan, Gilaad G; Ng, Siew C

    2016-12-01

    The UK and China provide unique historical perspectives on the evolution of the incidence of inflammatory bowel disease, which might provide insight into its pathogenesis. Historical records from the UK document the emergence of ulcerative colitis during the mid-1800s, which was later followed by the recognition of Crohn's disease in 1932. During the second half of the 20th century, the incidence of inflammatory bowel disease rose dramatically in high-income countries. Globalisation at the turn of the 21st century led to rapid economic development of newly industrialised countries such as China. In China, the modernisation of society was accompanied by the recognition of a sharp rise in the incidence of inflammatory bowel disease. The prevalence of inflammatory bowel disease is expected to continue to rise in high-income countries and is also likely to accelerate in the developing world. An understanding of the shared and different environmental determinants underpinning the pathogenesis of inflammatory bowel disease in western and eastern countries is essential to implement interventions that will blunt the rising global burden of inflammatory bowel disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Short bowel syndrome.

    LENUS (Irish Health Repository)

    Donohoe, Claire L

    2012-02-01

    The short bowel syndrome (SBS) is a state of malabsorption following intestinal resection where there is less than 200 cm of intestinal length. The management of short bowel syndrome can be challenging and is best managed by a specialised multidisciplinary team. A good understanding of the pathophysiological consequences of resection of different portions of the small intestine is necessary to anticipate and prevent, where possible, consequences of SBS. Nutrient absorption and fluid and electrolyte management in the initial stages are critical to stabilisation of the patient and to facilitate the process of adaptation. Pharmacological adjuncts to promote adaptation are in the early stages of development. Primary restoration of bowel continuity, if possible, is the principle mode of surgical treatment. Surgical procedures to increase the surface area of the small intestine or improve its function may be of benefit in experienced hands, particularly in the paediatric population. Intestinal transplant is indicated at present for patients who have failed to tolerate long-term parenteral nutrition but with increasing experience, there may be a potentially expanded role for its use in the future.

  4. Hydromagnetic theory of solar sectors: slow hydromagnetic waves

    International Nuclear Information System (INIS)

    Suess, S.T.

    1975-01-01

    Magnetic sectors on the sun are a feature, when the solar dipole field is subtracted, reminiscent of grapefruit sections in terms of the boundaries described by the magnetic field polarity change. One possible suggestion for the origin of these sectors is that they are hydromagnetic waves controlled by the rotation, toroidal magnetic field, and stratification within the convection zone of the sun. The merits of this suggestion are evaluated with respect to the observations and a specific theoretical model. 4 figs, 38 refs. (U.S.)

  5. Neurobiology of Depression and Irritable Bowel Syndrome Comorbidity

    Directory of Open Access Journals (Sweden)

    Ozlem Donat Eker

    2009-08-01

    Full Text Available Irritable bowel syndrome is a disabling functional disorder with a frequent comorbidity of depression though underlying mechanisms remain yet little understood. Various signs and symptoms have been determined as diagnostic criteria in recent years and standardized as Rome-III criteria. Irritable bowel syndrome can have constipation-dominant, diarrhea-dominant or mixed clinical presentations. Main features can be summarized as continuous and recurrent abdominal pain or discomfort associated with a change of stool frequency or consistency and usually relief of symptoms with defe-cation in the absence of physical or laboratory abnormalities indicative of an organic etiology. The frequency of major depressive disorder diagnosis reaches up to two thirds of irritable bowel syndrome patients. Moreover, the comorbidity of irritable bowel syndrome among patients with major depression is highly frequent (30%. The mechanism underlying irritable bowel syndrome which have been considered as a kind of a somatization disorder for a long time and now as a functional bowel disease is in the brain-gut axis. Low grade mucosal inflammation and cytokines originating from mucosal inflammation have important functions in the pathophysiology of irritable bowel syndrome and its comorbidity with major depression. Besides the inflammatory factors lumbosacral visceral hyperexcitability which is an individual variation is proposed as the main underlying cause of irritable bowel syndrome. Visceral hyper-excitability is mediated by cytokines and neuro-mediators and stress is known to increase the effect of this mechanism. Furthermore, molecules participating in this mechanism (e.g. cytokines, corticotrophin releasing factor, neurokinins and monoamines play important roles in the pathophysiology of depression. Increased activation in the pain matrix (thalamus – insula – prefrontal cortex and insufficiency of endogenous pain inhibitory system are regarded as possible

  6. Slowness Anomalies of PKP Phases Recorded at the Seismic Array in Eielson, Alaska (ILAR)

    Science.gov (United States)

    Koper, K. D.; Parker, V.

    2005-12-01

    The Eielson, Alaska seismic array (ILAR) is well situated to record PKPDF waves from earthquakes occurring in the South Sandwich Islands (SSI) region. Such ray paths are nearly aligned with Earth's rotation axis and are useful for constraining models of inner core anisotropy. The many previous studies of PKPDF waves traversing the SSI-Alaska corridor generally find waves that arrive several seconds faster than expected, with highly attenuated and often complicated shapes. Simple radially or cylindrically symmetric Earth models cannot explain these observations, and it may be the case that mantle heterogeneities are biasing the SSI-Alaska PKPDF waves. In this study, we take advantage of the small aperture of ILAR to make independent measurements of differential PKPDF-PKPBC travel times and differential PKPDF-PKPBC horizontal slowness vectors for 37 SSI earthquakes that occurred from 1996-2004. Anomalies in slowness (ray parameter and backazimuth) of a phase reflect heterogeneous Earth structure in a manner complementary to travel time anomalies. At a reference distance of 152°, we find a mean differential travel time residual of 3.1 ± 0.1~s, a mean differential ray parameter of 2.9±0.2~s/deg, and that PKPDF waves arrive from a backazimuth rotated approximately 10° counterclockwise relative to corresponding PKPBC waves. Joint modeling of the differential travel times and differential ray parameters indicates that (1) lower mantle heterogeneities are not responsible for the properties of PKPDF from SSI-ILAR, (2) the lower several hundred kilometers of the outer core has a slightly lower velocity, and/or velocity gradient, than current reference models, and (3) there is a strong, radial velocity gradient within the inner core at a radius of 600-900~km. However, the differential slowness anomalies cannot be fully explained by variations in deep Earth structure, implying that local site effects at ILAR are somewhat different for PKPDF and PKPBC phases.

  7. Muscarinic acetylcholine receptor expression in aganglionic bowel.

    Science.gov (United States)

    Oue, T; Yoneda, A; Shima, H; Puri, P

    2000-01-01

    In Hirschsprung's disease (HD) there exists an overabundance of acetylcholine (ACh), which in turn stimulates excessive production of the enzyme acetylcholinesterase. Muscarinic ACh receptors (mAChRs) play an important role in smooth-muscle contraction. Recent studies have indicated five different subtypes of mAChRs encoded by five different genes, ml to m5. The purpose of this study was to investigate the expression of each mAChR subtype in aganglionic (AG) colon to further understand the pathophysiology of HD. Entire colon resected at the time of pull-through operation for HD was obtained from 14 patients. Specimens obtained at autopsy from 8 age-matched patients without gastrointestinal disease acted as controls. Frozen sections were used for indirect immunohistochemistry as well as in-situ hybridization. Immunohistochemistry was performed using specific antiserum against each mAChR subtype and in-situ hybridization was performed using specific oligonucleotide probes against ml to m5 subtypes. Messenger RNA (mRNA) was extracted from normoganglionic (NG) and AG bowel of HD patients and normal control bowel. Reverse transcription-polymerase chain reaction was performed to evaluate mRNA levels of each mAChR subtype. To adjust the levels of mRNA expression, a housekeeping gene G3PDH, known to be expressed normally, was used as an internal control. Strong m2 and m3 immunoreactivity was observed in the mucosal layer, smooth-muscle layers, and myenteric plexus of NG bowel, whereas ml immunoreactivity was only detected in the mucosal layer. The most striking finding was the abundance of m3-immunoreactive fibers in muscle layers of NG bowel while there was a total lack of m3 fibers in smooth-muscle of AG bowel. Intense mRNA signals encoding m2 and m3 and to a lesser degree ml were detected in NG bowel, and these signals were weak in AG bowel. Immunoreactivity and mRNA expression of m4 and m5 was not detected in NG or AG bowel. The lack of m3-immunoreactive fibers in the

  8. Acoustic Enhancement of Sleep Slow Oscillations and Concomitant Memory Improvement in Older Adults

    Science.gov (United States)

    Papalambros, Nelly A.; Santostasi, Giovanni; Malkani, Roneil G.; Braun, Rosemary; Weintraub, Sandra; Paller, Ken A.; Zee, Phyllis C.

    2017-01-01

    Acoustic stimulation methods applied during sleep in young adults can increase slow wave activity (SWA) and improve sleep-dependent memory retention. It is unknown whether this approach enhances SWA and memory in older adults, who generally have reduced SWA compared to younger adults. Additionally, older adults are at risk for age-related cognitive impairment and therefore may benefit from non-invasive interventions. The aim of this study was to determine if acoustic stimulation can increase SWA and improve declarative memory in healthy older adults. Thirteen participants 60–84 years old completed one night of acoustic stimulation and one night of sham stimulation in random order. During sleep, a real-time algorithm using an adaptive phase-locked loop modeled the phase of endogenous slow waves in midline frontopolar electroencephalographic recordings. Pulses of pink noise were delivered when the upstate of the slow wave was predicted. Each interval of five pulses (“ON interval”) was followed by a pause of approximately equal length (“OFF interval”). SWA during the entire sleep period was similar between stimulation and sham conditions, whereas SWA and spindle activity were increased during ON intervals compared to matched periods during the sham night. The increases in SWA and spindle activity were sustained across almost the entire five-pulse ON interval compared to matched sham periods. Verbal paired-associate memory was tested before and after sleep. Overnight improvement in word recall was significantly greater with acoustic stimulation compared to sham and was correlated with changes in SWA between ON and OFF intervals. Using the phase-locked-loop method to precisely target acoustic stimulation to the upstate of sleep slow oscillations, we were able to enhance SWA and improve sleep-dependent memory storage in older adults, which strengthens the theoretical link between sleep and age-related memory integrity. PMID:28337134

  9. ON THE SPATIAL SCALES OF WAVE HEATING IN THE SOLAR CHROMOSPHERE

    International Nuclear Information System (INIS)

    Soler, Roberto; Ballester, Jose Luis; Carbonell, Marc

    2015-01-01

    Dissipation of magnetohydrodynamic (MHD) wave energy has been proposed as a viable heating mechanism in the solar chromospheric plasma. Here, we use a simplified one-dimensional model of the chromosphere to theoretically investigate the physical processes and spatial scales that are required for the efficient dissipation of Alfvén waves and slow magnetoacoustic waves. We consider the governing equations for a partially ionized hydrogen-helium plasma in the single-fluid MHD approximation and include realistic wave damping mechanisms that may operate in the chromosphere, namely, Ohmic and ambipolar magnetic diffusion, viscosity, thermal conduction, and radiative losses. We perform an analytic local study in the limit of small amplitudes to approximately derive the lengthscales for critical damping and efficient dissipation of MHD wave energy. We find that the critical dissipation lengthscale for Alfvén waves depends strongly on the magnetic field strength and ranges from 10 m to 1 km for realistic field strengths. The damping of Alfvén waves is dominated by Ohmic diffusion for weak magnetic field and low heights in the chromosphere, and by ambipolar diffusion for strong magnetic field and medium/large heights in the chromosphere. Conversely, the damping of slow magnetoacoustic waves is less efficient, and spatial scales shorter than 10 m are required for critical damping. Thermal conduction and viscosity govern the damping of slow magnetoacoustic waves and play an equally important role at all heights. These results indicate that the spatial scales at which strong wave heating may work in the chromosphere are currently unresolved by observations

  10. ON THE SPATIAL SCALES OF WAVE HEATING IN THE SOLAR CHROMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Soler, Roberto; Ballester, Jose Luis [Departament de Física, Universitat de les Illes Balears, E-07122, Palma de Mallorca (Spain); Carbonell, Marc, E-mail: roberto.soler@uib.es [Institute of Applied Computing and Community Code (IAC), Universitat de les Illes Balears, E-07122, Palma de Mallorca (Spain)

    2015-09-10

    Dissipation of magnetohydrodynamic (MHD) wave energy has been proposed as a viable heating mechanism in the solar chromospheric plasma. Here, we use a simplified one-dimensional model of the chromosphere to theoretically investigate the physical processes and spatial scales that are required for the efficient dissipation of Alfvén waves and slow magnetoacoustic waves. We consider the governing equations for a partially ionized hydrogen-helium plasma in the single-fluid MHD approximation and include realistic wave damping mechanisms that may operate in the chromosphere, namely, Ohmic and ambipolar magnetic diffusion, viscosity, thermal conduction, and radiative losses. We perform an analytic local study in the limit of small amplitudes to approximately derive the lengthscales for critical damping and efficient dissipation of MHD wave energy. We find that the critical dissipation lengthscale for Alfvén waves depends strongly on the magnetic field strength and ranges from 10 m to 1 km for realistic field strengths. The damping of Alfvén waves is dominated by Ohmic diffusion for weak magnetic field and low heights in the chromosphere, and by ambipolar diffusion for strong magnetic field and medium/large heights in the chromosphere. Conversely, the damping of slow magnetoacoustic waves is less efficient, and spatial scales shorter than 10 m are required for critical damping. Thermal conduction and viscosity govern the damping of slow magnetoacoustic waves and play an equally important role at all heights. These results indicate that the spatial scales at which strong wave heating may work in the chromosphere are currently unresolved by observations.

  11. Multidetector CT findings of bowel Transection in blunt abdominal trauma

    International Nuclear Information System (INIS)

    Cho, Hyun Suk; Woo, Ji Young; Hong, Hye Suk; Park, Mee Hyun; Yang, Ik; Lee, Yul; Jung, Ah Young; Hwang, Ji Young; Ha, Hong Il

    2013-01-01

    Though a number of CT findings of bowel and mesenteric injuries in blunt abdominal trauma are described in literature, no studies on the specific CT signs of a transected bowel have been published. In the present study we describe the incidence and new CT signs of bowel transection in blunt abdominal trauma. We investigated the incidence of bowel transection in 513 patients admitted for blunt abdominal trauma who underwent multidetector CT (MDCT). The MDCT findings of 8 patients with a surgically proven complete bowel transection were assessed retrospectively. We report novel CT signs that are unique for transection, such as complete cutoff sign (transection of bowel loop), Janus sign (abnormal dual bowel wall enhancement, both increased and decreased), and fecal spillage. The incidence of bowel transection in blunt abdominal trauma was 1.56%. In eight cases of bowel transection, percentage of CT signs unique for bowel transection were as follows: complete cutoff in 8 (100%), Janus sign in 6 (100%, excluding duodenal injury), and fecal spillage in 2 (25%). The combination of complete cutoff and Janus sign were highly specific findings in patients with bowel transection. Complete cut off and Janus sign are the unique CT findings to help detect bowel transection in blunt abdominal trauma and recognition of these findings enables an accurate and prompt diagnosis for emergency laparotomy leading to reduced mortality and morbidity.

  12. The 2012 Mw5.6 earthquake in Sofia seismogenic zone - is it a slow earthquake

    Science.gov (United States)

    Raykova, Plamena; Solakov, Dimcho; Slavcheva, Krasimira; Simeonova, Stela; Aleksandrova, Irena

    2017-04-01

    very low rupture velocity. The low rupture velocity can mean slow-faulting, which brings to slow release of accumulated seismic energy. The slow release energy does principally little to moderate damages. Additionally wave form of the earthquake shows low frequency content of P-waves (the maximum P-wave is at 1.19 Hz) and the specific P- wave displacement spectral is characterise with not expressed spectrum plateau and corner frequency. These and other signs suggest us to the conclusion, that the 2012 Mw5.6 earthquake can be considered as types of slow earthquake, like a low frequency quake. The study is based on data from Bulgarian seismological network (NOTSSI), the local network (LSN) deployed around Kozloduy NPP and System of Accelerographs for Seismic Monitoring of Equipment and Structures (SASMES) installed in the Kozloduy NPP. NOTSSI jointly with LSN and SASMES provide reliable information for multiple studies on seismicity in regional scale.

  13. Heterotaxy syndromes and abnormal bowel rotation

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Beverley [Stanford University, Lucile Packard Children' s Hospital, Department of Radiology, Stanford, CA (United States); Koppolu, Raji; Sylvester, Karl [Lucile Packard Children' s Hospital at Stanford, Department of Surgery, Stanford, CA (United States); Murphy, Daniel [Lucile Packard Children' s Hospital at Stanford, Department of Cardiology, Stanford, CA (United States)

    2014-05-15

    Bowel rotation abnormalities in heterotaxy are common. As more children survive cardiac surgery, the management of gastrointestinal abnormalities has become controversial. To evaluate imaging of malrotation in heterotaxy with surgical correlation and provide an algorithm for management. Imaging reports of heterotaxic children with upper gastrointestinal (UGI) and/or small bowel follow-through (SBFT) were reviewed. Subsequently, fluoroscopic images were re-reviewed in conjunction with CT/MR studies. The original reports and re-reviewed images were compared and correlated with surgical findings. Nineteen of 34 children with heterotaxy underwent UGI, 13/19 also had SBFT. In 15/19 reports, bowel rotation was called abnormal: 11 malrotation, 4 non-rotation, no cases of volvulus. Re-review, including CT (10/19) and MR (2/19), designated 17/19 (90%) as abnormal, 10 malrotation (abnormal bowel arrangement, narrow or uncertain length of mesentery) and 7 non-rotation (small bowel and colon on opposite sides plus low cecum with probable broad mesentery). The most useful CT/MR findings were absence of retroperitoneal duodenum in most abnormal cases and location of bowel, especially cecum. Abnormal orientation of mesenteric vessels suggested malrotation but was not universal. Nine children had elective bowel surgery; non-rotation was found in 4/9 and malrotation was found in 5/9, with discrepancies (non-rotation at surgery, malrotation on imaging) with 4 original interpretations and 1 re-review. We recommend routine, early UGI and SBFT studies once other, urgent clinical concerns have been stabilized, with elective laparoscopic surgery in abnormal or equivocal cases. Cross-sectional imaging, usually obtained for other reasons, can contribute diagnostically. Attempting to assess mesenteric width is important in differentiating non-rotation from malrotation and more accurately identifies appropriate surgical candidates. (orig.)

  14. Heterotaxy syndromes and abnormal bowel rotation

    International Nuclear Information System (INIS)

    Newman, Beverley; Koppolu, Raji; Sylvester, Karl; Murphy, Daniel

    2014-01-01

    Bowel rotation abnormalities in heterotaxy are common. As more children survive cardiac surgery, the management of gastrointestinal abnormalities has become controversial. To evaluate imaging of malrotation in heterotaxy with surgical correlation and provide an algorithm for management. Imaging reports of heterotaxic children with upper gastrointestinal (UGI) and/or small bowel follow-through (SBFT) were reviewed. Subsequently, fluoroscopic images were re-reviewed in conjunction with CT/MR studies. The original reports and re-reviewed images were compared and correlated with surgical findings. Nineteen of 34 children with heterotaxy underwent UGI, 13/19 also had SBFT. In 15/19 reports, bowel rotation was called abnormal: 11 malrotation, 4 non-rotation, no cases of volvulus. Re-review, including CT (10/19) and MR (2/19), designated 17/19 (90%) as abnormal, 10 malrotation (abnormal bowel arrangement, narrow or uncertain length of mesentery) and 7 non-rotation (small bowel and colon on opposite sides plus low cecum with probable broad mesentery). The most useful CT/MR findings were absence of retroperitoneal duodenum in most abnormal cases and location of bowel, especially cecum. Abnormal orientation of mesenteric vessels suggested malrotation but was not universal. Nine children had elective bowel surgery; non-rotation was found in 4/9 and malrotation was found in 5/9, with discrepancies (non-rotation at surgery, malrotation on imaging) with 4 original interpretations and 1 re-review. We recommend routine, early UGI and SBFT studies once other, urgent clinical concerns have been stabilized, with elective laparoscopic surgery in abnormal or equivocal cases. Cross-sectional imaging, usually obtained for other reasons, can contribute diagnostically. Attempting to assess mesenteric width is important in differentiating non-rotation from malrotation and more accurately identifies appropriate surgical candidates. (orig.)

  15. Fast and slow light generated by surface plasmon wave and gold grating coupling effects

    Science.gov (United States)

    Amiri, Iraj S.; Ariannejad, M. M.; Tajdidzadeh, M.; Sorger, Volker J.; Ling, Xi; Yupapin, P.

    2018-01-01

    We present here the results of a simulation of the effect of gold and graphene coatings on silicon micro-ring resonators. We studied the effect of different radii of graphene on the time delay, from which one an interesting aspect of light pulse behaviors, such as fast light, was numerically investigated. The obtained results indicate that the time delay can be varied, which is in good agreement with theoretical predictions. Fast and slow light pulse trains can be obtained by modifying the throughput port, which forms the gold grating length. The temporal gaps between the fast and slow light in the used graphene and gold are 140 and 168 fs, respectively, which can be tuned by varying the radius or grating length. The obtained results show that such a device may be useful in applications requiring fast and slow light pulse train pairs, such as optical switching, sensors, communications, and security applications.

  16. Evolution Of Nonlinear Waves in Compressing Plasma

    International Nuclear Information System (INIS)

    Schmit, P.F.; Dodin, I.Y.; Fisch, N.J.

    2011-01-01

    Through particle-in-cell simulations, the evolution of nonlinear plasma waves is examined in one-dimensional collisionless plasma undergoing mechanical compression. Unlike linear waves, whose wavelength decreases proportionally to the system length L(t), nonlinear waves, such as solitary electron holes, conserve their characteristic size Δ during slow compression. This leads to a substantially stronger adiabatic amplification as well as rapid collisionless damping when L approaches Δ. On the other hand, cessation of compression halts the wave evolution, yielding a stable mode.

  17. Evolution Of Nonlinear Waves in Compressing Plasma

    Energy Technology Data Exchange (ETDEWEB)

    P.F. Schmit, I.Y. Dodin, and N.J. Fisch

    2011-05-27

    Through particle-in-cell simulations, the evolution of nonlinear plasma waves is examined in one-dimensional collisionless plasma undergoing mechanical compression. Unlike linear waves, whose wavelength decreases proportionally to the system length L(t), nonlinear waves, such as solitary electron holes, conserve their characteristic size {Delta} during slow compression. This leads to a substantially stronger adiabatic amplification as well as rapid collisionless damping when L approaches {Delta}. On the other hand, cessation of compression halts the wave evolution, yielding a stable mode.

  18. Borehole stoneley waves and permeability: Laboratory results

    International Nuclear Information System (INIS)

    Winkler, K.W.; Plona, T.J.; Froelich, B.; Liu, H.L.

    1987-01-01

    Recent interest in full waveform sonic logging has created the need for full waveform laboratory experiments on model boreholes. Of particular interest is the investigation of Stoneley waves and their interaction with permeable formations. The authors describe experimental results that show how Stoneley wave slowness and attenuation are affected by formation permeability. Both slowness and attenuation (1/Q) are observed to increase with formation permeability. This increase is frequency dependent, being greatest at low frequencies. The presence of simulated mudcakes on the borehole wall reduces the permeability effect on Stoneley waves, but does not eliminate it. The mudcake effect is frequency dependent, being greatest at low frequencies. In our experiments on rocks, the laboratory data is in qualitative agreement with theoretical predictions. In a very well characterized synthetic porous material, theory and experiment are in good quantitative agreement

  19. CHROMOSPHERIC AND CORONAL WAVE GENERATION IN A MAGNETIC FLUX SHEATH

    International Nuclear Information System (INIS)

    Kato, Yoshiaki; Hansteen, Viggo; Gudiksen, Boris; Wedemeyer, Sven; Carlsson, Mats; Steiner, Oskar

    2016-01-01

    Using radiation magnetohydrodynamic simulations of the solar atmospheric layers from the upper convection zone to the lower corona, we investigate the self-consistent excitation of slow magneto-acoustic body waves (slow modes) in a magnetic flux concentration. We find that the convective downdrafts in the close surroundings of a two-dimensional flux slab “pump” the plasma inside it in the downward direction. This action produces a downflow inside the flux slab, which encompasses ever higher layers, causing an upwardly propagating rarefaction wave. The slow mode, excited by the adiabatic compression of the downflow near the optical surface, travels along the magnetic field in the upward direction at the tube speed. It develops into a shock wave at chromospheric heights, where it dissipates, lifts the transition region, and produces an offspring in the form of a compressive wave that propagates further into the corona. In the wake of downflows and propagating shock waves, the atmosphere inside the flux slab in the chromosphere and higher tends to oscillate with a period of ν ≈ 4 mHz. We conclude that this process of “magnetic pumping” is a most plausible mechanism for the direct generation of longitudinal chromospheric and coronal compressive waves within magnetic flux concentrations, and it may provide an important heat source in the chromosphere. It may also be responsible for certain types of dynamic fibrils.

  20. CHROMOSPHERIC AND CORONAL WAVE GENERATION IN A MAGNETIC FLUX SHEATH

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Yoshiaki; Hansteen, Viggo; Gudiksen, Boris; Wedemeyer, Sven; Carlsson, Mats [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Steiner, Oskar, E-mail: yoshiaki.kato@astro.uio.no [Kiepenheuer-Institut für Sonnenphysik, Schöneckstrasse 6, D-79104 Freiburg (Germany)

    2016-08-10

    Using radiation magnetohydrodynamic simulations of the solar atmospheric layers from the upper convection zone to the lower corona, we investigate the self-consistent excitation of slow magneto-acoustic body waves (slow modes) in a magnetic flux concentration. We find that the convective downdrafts in the close surroundings of a two-dimensional flux slab “pump” the plasma inside it in the downward direction. This action produces a downflow inside the flux slab, which encompasses ever higher layers, causing an upwardly propagating rarefaction wave. The slow mode, excited by the adiabatic compression of the downflow near the optical surface, travels along the magnetic field in the upward direction at the tube speed. It develops into a shock wave at chromospheric heights, where it dissipates, lifts the transition region, and produces an offspring in the form of a compressive wave that propagates further into the corona. In the wake of downflows and propagating shock waves, the atmosphere inside the flux slab in the chromosphere and higher tends to oscillate with a period of ν ≈ 4 mHz. We conclude that this process of “magnetic pumping” is a most plausible mechanism for the direct generation of longitudinal chromospheric and coronal compressive waves within magnetic flux concentrations, and it may provide an important heat source in the chromosphere. It may also be responsible for certain types of dynamic fibrils.

  1. Fiber and Saturated Fat Are Associated with Sleep Arousals and Slow Wave Sleep.

    Science.gov (United States)

    St-Onge, Marie-Pierre; Roberts, Amy; Shechter, Ari; Choudhury, Arindam Roy

    2016-01-01

    Sleep restriction alters food intake, but less is known about how dietary patterns affect sleep. Current goals were to determine whether: (1) sleep is different after consumption of a controlled diet vs. an ad libitum diet, and (2) dietary intake during ad libitum feeding is related to nocturnal sleep. Twenty-six normal weight adults (30-45 y), habitually sleeping 7-9 h/night, participated in a randomized-crossover inpatient study with 2 phases of 5 nights: short (4 h in bed) or habitual (9 h in bed) sleep. Only data from the habitual sleep phase were used for the present analyses. During the first 4 days, participants consumed a controlled diet; on day 5, food intake was self-selected. Linear regression was used to determine relations between daytime food intake and nighttime sleep on day 5. Sleep duration did not differ after 3 days of controlled feeding vs. a day of ad libitum intake. However, sleep after ad libitum eating had less slow wave sleep (SWS, P = 0.0430) and longer onset latency (P = 0.0085). Greater fiber intake predicted less stage 1 (P = 0.0198) and more SWS (P = 0.0286). Percent of energy from saturated fat predicted less SWS (P = 0.0422). Higher percent of energy from sugar and other carbohydrates not considered sugar or fiber was associated with arousals (P = 0.0320 and 0.0481, respectively). Low fiber and high saturated fat and sugar intake is associated with lighter, less restorative sleep with more arousals. Diet could be useful in the management of sleep disorders but this needs to be tested. http://www.clinicaltrials.gov, #NCT00935402. © 2016 American Academy of Sleep Medicine.

  2. Multislice CT enteroclysis in the diagnosis of bowel endometriosis

    International Nuclear Information System (INIS)

    Biscaldi, Ennio; Rollandi, Gian A.; Ferrero, Simone; Ragni, Nicola; Remorgida, Valentino; Fulcheri, Ezio

    2007-01-01

    This prospective study aims to evaluate the efficacy of multislice computed tomography combined with colon distension by water enteroclysis (MSCTe) in determining the presence and depth of bowel endometriotic lesions. Ninety-eight women with symptoms suggestive of colorectal endometriosis underwent MSCTe; locations, number of nodule/s, size of the nodule/s and depth of bowel wall infiltration were determined. Independently from the findings of MSCTe, all women underwent laparoscopy. MSCTe findings were compared with surgical and histological results. Abnormal findings suggestive of bowel endometriotic nodules were detected by MSCTe in 75 of the 76 patients with bowel endometriosis. MSCTe identified 110 (94.8%) of the 116 bowel endometriotic nodules removed at surgery; 6 nodules missed at MSCTe were located on the rectum. MSCTe correctly determined the degree of infiltration of the bowel wall in all of the 34 serosal bowel nodules identified at MSCTe. In six nodules reaching the submucosa, the depth of infiltration was underestimated by MSCTe. MSCTe had a sensitivity of 98.7%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 95.7% in identifying women with bowel endometriosis. MSCTe is effective in determining the presence and depth of bowel endometriotic lesions. (orig.)

  3. Multislice CT enteroclysis in the diagnosis of bowel endometriosis

    Energy Technology Data Exchange (ETDEWEB)

    Biscaldi, Ennio; Rollandi, Gian A. [' ' Duchesse of Galliera' ' -Hospital, Genoa (Italy). Dept. of Radiology; Ferrero, Simone; Ragni, Nicola; Remorgida, Valentino [San Martino Hospital and Genoa Univ. (Italy). Dept. of Obstretics and Gynaecology; Fulcheri, Ezio [San Martino Hospital and Genoa Univ. (Italy). Unit of Anatomy and Histopathology

    2007-01-15

    This prospective study aims to evaluate the efficacy of multislice computed tomography combined with colon distension by water enteroclysis (MSCTe) in determining the presence and depth of bowel endometriotic lesions. Ninety-eight women with symptoms suggestive of colorectal endometriosis underwent MSCTe; locations, number of nodule/s, size of the nodule/s and depth of bowel wall infiltration were determined. Independently from the findings of MSCTe, all women underwent laparoscopy. MSCTe findings were compared with surgical and histological results. Abnormal findings suggestive of bowel endometriotic nodules were detected by MSCTe in 75 of the 76 patients with bowel endometriosis. MSCTe identified 110 (94.8%) of the 116 bowel endometriotic nodules removed at surgery; 6 nodules missed at MSCTe were located on the rectum. MSCTe correctly determined the degree of infiltration of the bowel wall in all of the 34 serosal bowel nodules identified at MSCTe. In six nodules reaching the submucosa, the depth of infiltration was underestimated by MSCTe. MSCTe had a sensitivity of 98.7%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 95.7% in identifying women with bowel endometriosis. MSCTe is effective in determining the presence and depth of bowel endometriotic lesions. (orig.)

  4. Small Bowel Transplantation: Current Clinical Status

    Directory of Open Access Journals (Sweden)

    David Sigalet

    1991-01-01

    Full Text Available With recent refinements in immunosuppression techniques, the first successful reports of small bowel transplantation in humans have now been made, increasing interest in bowel transplantation among clinicians and patients alike. This article reviews recent developments in understanding of the functional capabilities and requirements for effective immune suppression in bowel transplantation. Both experimental and clinical experience with transplantation are discussed, as are the areas which appear to offer the most promise for future developments. Finally guidelines for consideration of patient selection for this procedure are reviewed.

  5. Small-bowel permeability in collagenous colitis

    DEFF Research Database (Denmark)

    Wildt, Signe; Madsen, Jan L; Rumessen, Jüri J

    2006-01-01

    Collagenous colitis (CC) is a chronic inflammatory bowel disease that affects the colon. However, some patients with CC present with accompanying pathologic small-bowel manifestations such as coeliac disease, defects in bile acid absorption and histopathologic changes in small-intestinal biopsies......, indicating that CC is a pan-intestinal disease. In small-intestinal disease, the intestinal barrier function may be impaired, and the permeability of the small intestine altered. The purpose of this research was to study small-bowel function in patients with CC as expressed by intestinal permeability....

  6. Slow oscillation amplitudes and up-state lengths relate to memory improvement.

    Directory of Open Access Journals (Sweden)

    Dominik P J Heib

    Full Text Available There is growing evidence of the active involvement of sleep in memory consolidation. Besides hippocampal sharp wave-ripple complexes and sleep spindles, slow oscillations appear to play a key role in the process of sleep-associated memory consolidation. Furthermore, slow oscillation amplitude and spectral power increase during the night after learning declarative and procedural memory tasks. However, it is unresolved whether learning-induced changes specifically alter characteristics of individual slow oscillations, such as the slow oscillation up-state length and amplitude, which are believed to be important for neuronal replay. 24 subjects (12 men aged between 20 and 30 years participated in a randomized, within-subject, multicenter study. Subjects slept on three occasions for a whole night in the sleep laboratory with full polysomnography. Whereas the first night only served for adaptation purposes, the two remaining nights were preceded by a declarative word-pair task or by a non-learning control task. Slow oscillations were detected in non-rapid eye movement sleep over electrode Fz. Results indicate positive correlations between the length of the up-state as well as the amplitude of both slow oscillation phases and changes in memory performance from pre to post sleep. We speculate that the prolonged slow oscillation up-state length might extend the timeframe for the transfer of initial hippocampal to long-term cortical memory representations, whereas the increase in slow oscillation amplitudes possibly reflects changes in the net synaptic strength of cortical networks.

  7. Determination of S-wave slowness from a linear array of borehole receivers

    Czech Academy of Sciences Publication Activity Database

    Eisner, L.; Fischer, Tomáš; Rutledge, J. T.

    2009-01-01

    Roč. 176, č. 1 (2009), s. 31-39 ISSN 0956-540X Grant - others:EC(XE) MTKI-CT-2004-517242 Institutional research plan: CEZ:AV0Z30120515 Keywords : downhole methods * controlled source seismology * body waves * wave propagation Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.435, year: 2009

  8. Emergence of slow collective oscillations in neural networks with spike-timing dependent plasticity

    DEFF Research Database (Denmark)

    Mikkelsen, Kaare; Imparato, Alberto; Torcini, Alessandro

    2013-01-01

    The collective dynamics of excitatory pulse coupled neurons with spike timing dependent plasticity (STDP) is studied. The introduction of STDP induces persistent irregular oscillations between strongly and weakly synchronized states, reminiscent of brain activity during slow-wave sleep. We explain...

  9. Direct detection of the inflationary gravitational-wave background

    International Nuclear Information System (INIS)

    Smith, Tristan L.; Kamionkowski, Marc; Cooray, Asantha

    2006-01-01

    Inflation generically predicts a stochastic background of gravitational waves over a broad range of frequencies, from those accessible with cosmic microwave background (CMB) measurements, to those accessible directly with gravitational-wave detectors, like NASA's Big-Bang Observer (BBO) or Japan's Deci-Hertz Interferometer Gravitational-wave Observer (DECIGO), both currently under study. Here we investigate the detectability of the inflationary gravitational-wave background at BBO/DECIGO frequencies. To do so, we survey a range of slow-roll inflationary models consistent with constraints from the CMB and large-scale structure (LSS). We go beyond the usual assumption of power-law power spectra, which may break down given the 16 orders of magnitude in frequency between the CMB and direct detection, and solve instead the inflationary dynamics for four classes of inflaton potentials. Direct detection is possible in a variety of inflationary models, although probably not in any in which the gravitational-wave signal does not appear in the CMB polarization. However, direct detection by BBO/DECIGO can help discriminate between inflationary models that have the same slow-roll parameters at CMB/LSS scales

  10. Plain magnetic resonance imaging as an alternative in evaluating inflammation and bowel damage in inflammatory bowel disease

    DEFF Research Database (Denmark)

    Jesuratnam-Nielsen, Kayalvily; Løgager, Vibeke B; Rezanavaz-Gheshlagh, Bijan

    2015-01-01

    -52%, 83-94% and 76-92% for DWI, respectively. The κ values for bowel wall thickening, DWI, and mural hyperenhancement were detected with fair agreement (κ = 0.26-0.39) at both MRI examinations, whereas only bowel wall thickening in MRFT were detected with moderate agreement (κ = 0.47) Conclusion. Plain......OBJECTIVE: To compare prospectively the diagnostic accuracy of magnetic resonance imaging (MRI) without use of contrast medium orally or intravenously (plain MRI) with magnetic resonance follow-through (MRFT) in patients with inflammatory bowel disease (IBD). MATERIAL AND METHODS: Plain MRI...

  11. On MHD waves, fire-hose and mirror instabilities in anisotropic plasmas

    Directory of Open Access Journals (Sweden)

    L.-N. Hau

    2007-09-01

    Full Text Available Temperature or pressure anisotropies are characteristic of space plasmas, standard magnetohydrodynamic (MHD model for describing large-scale plasma phenomena however usually assumes isotropic pressure. In this paper we examine the characteristics of MHD waves, fire-hose and mirror instabilities in anisotropic homogeneous magnetized plasmas. The model equations are a set of gyrotropic MHD equations closed by the generalized Chew-Goldberger-Low (CGL laws with two polytropic exponents representing various thermodynamic conditions. Both ions and electrons are allowed to have separate plasma beta, pressure anisotropy and energy equations. The properties of linear MHD waves and instability criteria are examined and numerical examples for the nonlinear evolutions of slow waves, fire-hose and mirror instabilities are shown. One significant result is that slow waves may develop not only mirror instability but also a new type of compressible fire-hose instability. Their corresponding nonlinear structures thus may exhibit anticorrelated density and magnetic field perturbations, a property used for identifying slow and mirror mode structures in the space plasma environment. The conditions for nonlinear saturation of both fire-hose and mirror instabilities are examined.

  12. Large-Amplitude Long-Wave Instability of a Supersonic Shear Layer

    Science.gov (United States)

    Messiter, A. F.

    1995-01-01

    For sufficiently high Mach numbers, small disturbances on a supersonic vortex sheet are known to grow in amplitude because of slow nonlinear wave steepening. Under the same external conditions, linear theory predicts slow growth of long-wave disturbances to a thin supersonic shear layer. An asymptotic formulation is given here which adds nonzero shear-layer thickness to the weakly nonlinear formulation for a vortex sheet. Spatial evolution is considered, for a spatially periodic disturbance having amplitude of the same order, in Reynolds number, as the shear-layer thickness. A quasi-equilibrium inviscid nonlinear critical layer is found, with effects of diffusion and slow growth appearing through nonsecularity condition. Other limiting cases are also considered, in an attempt to determine a relationship between the vortex-sheet limit and the long-wave limit for a thin shear layer; there appear to be three special limits, corresponding to disturbances of different amplitudes at different locations along the shear layer.

  13. Spectral analysis of bowel sounds in intestinal obstruction using an electronic stethoscope.

    Science.gov (United States)

    Ching, Siok Siong; Tan, Yih Kai

    2012-09-07

    To determine the value of bowel sounds analysis using an electronic stethoscope to support a clinical diagnosis of intestinal obstruction. Subjects were patients who presented with a diagnosis of possible intestinal obstruction based on symptoms, signs, and radiological findings. A 3M™ Littmann(®) Model 4100 electronic stethoscope was used in this study. With the patients lying supine, six 8-second recordings of bowel sounds were taken from each patient from the lower abdomen. The recordings were analysed for sound duration, sound-to-sound interval, dominant frequency, and peak frequency. Clinical and radiological data were reviewed and the patients were classified as having either acute, subacute, or no bowel obstruction. Comparison of bowel sound characteristics was made between these subgroups of patients. In the presence of an obstruction, the site of obstruction was identified and bowel calibre was also measured to correlate with bowel sounds. A total of 71 patients were studied during the period July 2009 to January 2011. Forty patients had acute bowel obstruction (27 small bowel obstruction and 13 large bowel obstruction), 11 had subacute bowel obstruction (eight in the small bowel and three in large bowel) and 20 had no bowel obstruction (diagnoses of other conditions were made). Twenty-five patients received surgical intervention (35.2%) during the same admission for acute abdominal conditions. A total of 426 recordings were made and 420 recordings were used for analysis. There was no significant difference in sound-to-sound interval, dominant frequency, and peak frequency among patients with acute bowel obstruction, subacute bowel obstruction, and no bowel obstruction. In acute large bowel obstruction, the sound duration was significantly longer (median 0.81 s vs 0.55 s, P = 0.021) and the dominant frequency was significantly higher (median 440 Hz vs 288 Hz, P = 0.003) when compared to acute small bowel obstruction. No significant difference was seen

  14. Solitary wave evolution in a magnetized inhomogeneous plasma under the effect of ionization

    International Nuclear Information System (INIS)

    Jyoti; Malik, Hitendra K.

    2011-01-01

    A modified form of Korteweg-deVries (KdV) equation appropriate to nonlinear ion acoustic solitary waves in an inhomogeneous plasma is derived in the presence of an external magnetic field and constant ionization in the plasma. This equation differs from usual version of the KdV equation because of the inclusion of two terms arising due to ionization and density gradient present in the plasma. In this plasma, only the compressive solitary waves are found to propagate corresponding to the fast and slow modes. The amplitude of the solitary wave increases with an enhancement in the ionization for the fast mode as well as for the slow mode. The effect of magnetic field is to enhance the width of the solitary structure. The amplitude is found to increase (decrease) with an enhancement in charge number of the ions for the fast (slow) mode. The tailing structure becomes more (less) prominent with the rise in ion drift velocity for the case of fast (slow) mode.

  15. The research progress of acute small bowel perforation

    Directory of Open Access Journals (Sweden)

    Rudolf Schiessel

    2015-08-01

    Full Text Available This article reviews the various aetiologies of small bowel perforations and their management. In addition to the well-known aetiologies such as trauma, inflammation and circulatory disorders, several new causes of small bowel perforation have been described in recent years. The spectrum reaches from iatrogenic perforations during laparoscopic surgery or enteroscopies to drug-induced perforations with new anticancer agents. The management of small bowel perforations requires a concept consisting of the safe revision of the leaking bowel and the treatment of the peritonitis. Depending on the local situation and the condition of the patient, several treatment options are available. The surgical management of the bowel leak can range from a simple primary closure to a delayed restoration of bowel continuity. When the condition of the bowel or patient is frail, the risk of a failure of a closure or anastomosis is too high, and the exteriorization of the bowel defect as a primary measure is a safe option. The treatment of the peritonitis is also dependent on the condition of the patient and the local situation. Early stages of peritonitis can be treated by a simple peritoneal lavage, either performed by laparoscopy or laparotomy. Severe forms of peritonitis with multi-organ failure and an abdominal compartment syndrome need repeated peritoneal revisions. In such cases, the abdomen can only be closed temporarily. Different technical options are available in order to overcome the difficult care of these patients.

  16. Numerical Simulations of Slow Stick Slip Events with PFC, a DEM Based Code

    Science.gov (United States)

    Ye, S. H.; Young, R. P.

    2017-12-01

    Nonvolcanic tremors around subduction zone have become a fascinating subject in seismology in recent years. Previous studies have shown that the nonvolcanic tremor beneath western Shikoku is composed of low frequency seismic waves overlapping each other. This finding provides direct link between tremor and slow earthquakes. Slow stick slip events are considered to be laboratory scaled slow earthquakes. Slow stick slip events are traditionally studied with direct shear or double direct shear experiment setup, in which the sliding velocity can be controlled to model a range of fast and slow stick slips. In this study, a PFC* model based on double direct shear is presented, with a central block clamped by two side blocks. The gauge layers between the central and side blocks are modelled as discrete fracture networks with smooth joint bonds between pairs of discrete elements. In addition, a second model is presented in this study. This model consists of a cylindrical sample subjected to triaxial stress. Similar to the previous model, a weak gauge layer at a 45 degrees is added into the sample, on which shear slipping is allowed. Several different simulations are conducted on this sample. While the confining stress is maintained at the same level in different simulations, the axial loading rate (displacement rate) varies. By varying the displacement rate, a range of slipping behaviour, from stick slip to slow stick slip are observed based on the stress-strain relationship. Currently, the stick slip and slow stick slip events are strictly observed based on the stress-strain relationship. In the future, we hope to monitor the displacement and velocity of the balls surrounding the gauge layer as a function of time, so as to generate a synthetic seismogram. This will allow us to extract seismic waveforms and potentially simulate the tremor-like waves found around subduction zones. *Particle flow code, a discrete element method based numerical simulation code developed by

  17. Observaton of tunneling of slow and fast electromagnetic modes in coupled periodic waveguides

    DEFF Research Database (Denmark)

    Ha, Sangwoo; Sukhorukov, Andrey A.; Lavrinenko, Andrei

    2011-01-01

    We report the experimental observation of tunneling of slow and fast electromagnetic modes in coupled periodic waveguides shifted longitudinally by half of modulation period. According to the symmetry analysis, such a coupler supports two electromagnetic modes with exactly matched slow or fast...... group velocities but different phase velocities for frequencies close to the edge of the photonic band. We confirm the predicted properties of the modes by directly extracting their dispersion and group velocities from the near-field measurements using specialized Bloch-wave spectral analysis method....

  18. Usefulness of bowel sound auscultation: a prospective evaluation.

    Science.gov (United States)

    Felder, Seth; Margel, David; Murrell, Zuri; Fleshner, Phillip

    2014-01-01

    Although the auscultation of bowel sounds is considered an essential component of an adequate physical examination, its clinical value remains largely unstudied and subjective. The aim of this study was to determine whether an accurate diagnosis of normal controls, mechanical small bowel obstruction (SBO), or postoperative ileus (POI) is possible based on bowel sound characteristics. Prospectively collected recordings of bowel sounds from patients with normal gastrointestinal motility, SBO diagnosed by computed tomography and confirmed at surgery, and POI diagnosed by clinical symptoms and a computed tomography without a transition point. Study clinicians were instructed to categorize the patient recording as normal, obstructed, ileus, or not sure. Using an electronic stethoscope, bowel sounds of healthy volunteers (n = 177), patients with SBO (n = 19), and patients with POI (n = 15) were recorded. A total of 10 recordings randomly selected from each category were replayed through speakers, with 15 of the recordings duplicated to surgical and internal medicine clinicians (n = 41) blinded to the clinical scenario. The sensitivity, positive predictive value, and intra-rater variability were determined based on the clinician's ability to properly categorize the bowel sound recording when blinded to additional clinical information. Secondary outcomes were the clinician's perceived level of expertise in interpreting bowel sounds. The overall sensitivity for normal, SBO, and POI recordings was 32%, 22%, and 22%, respectively. The positive predictive value of normal, SBO, and POI recordings was 23%, 28%, and 44%, respectively. Intra-rater reliability of duplicated recordings was 59%, 52%, and 53% for normal, SBO, and POI, respectively. No statistically significant differences were found between the surgical and internal medicine clinicians for sensitivity, positive predictive value, or intra-rater variability. Overall, 44% of clinicians reported that they rarely listened

  19. Surgical perspectives on inflammatory bowel disease

    African Journals Online (AJOL)

    VikasC

    Xia B, Crusius JBA, Meuwissen SGM, Pena AS. Inflammatory bowel disease: Definition, epidemiology, etiologic aspects, and immunologic studies. World J. Gastroentero 1998;4:44658. 2. Fry DR, Mahmood N, Maron DJ, Ross HM, Rombeau. J. Inflammatory bowel disease in Towsend: Sabiston. Textbook of Surgery.

  20. Wave-particle interaction and Hamiltonian dynamics investigated in a traveling wave tube

    International Nuclear Information System (INIS)

    Doveil, Fabrice; Macor, Alessandro

    2006-01-01

    For wave-particle interaction studies, the one-dimensional (1-D) beam-plasma system can be advantageously replaced by a Traveling Wave Tube (TWT). This led us to a detailed experimental analysis of the self-consistent interaction between unstable waves and a small either cold or warm beam. More recently, a test electron beam has been used to observe its non-self-consistent interaction with externally excited wave(s). The velocity distribution function of the electron beam is investigated with a trochoidal energy analyzer that records the beam energy distribution at the output of the TWT. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the slow wave structure (a 4 m long helix) of the TWT. The nonlinear synchronization of particles by a single wave responsible for Landau damping is observed. The resonant velocity domain associated to a single wave is also observed, as well as the transition to large-scale chaos when the resonant domains of two waves and their secondary resonances overlap leading to a typical 'devil's staircase' behavior. A new strategy for the control of chaos is tested

  1. Enhancing Wave Energy Competitiveness through Co-Located Wind and Wave Energy Farms. A Review on the Shadow Effect

    OpenAIRE

    Sharay Astariz; Gregorio Iglesias

    2015-01-01

    Wave energy is one of the most promising alternatives to fossil fuels due to the enormous available resource; however, its development may be slowed as it is often regarded as uneconomical. The largest cost reductions are expected to be obtained through economies of scale and technological progress. In this sense, the incorporation of wave energy systems into offshore wind energy farms is an opportunity to foster the development of wave energy. The synergies between both renewables can be rea...

  2. Reduction in Cortical Gamma Synchrony during Depolarized State of Slow Wave Activity in Mice

    Directory of Open Access Journals (Sweden)

    EUNJIN eHWANG

    2013-12-01

    Full Text Available EEG gamma band oscillations have been proposed to account for the neural synchronization crucial for perceptual integration. While increased gamma power and synchronization is generally observed during cognitive tasks performed during wake, several studies have additionally reported increased gamma power during sleep or anesthesia, raising questions about the characteristics of gamma oscillation during impaired consciousness and its role in conscious processing. Phase-amplitude modulation has been observed between slow wave activity (SWA, 0.5–4 Hz and gamma oscillations during ketamine/xylazine anesthesia or sleep, showing increased gamma activity corresponding to the depolarized (ON state of SWA. Here we divided gamma activity into its ON and OFF (hyperpolarized state components based on the phase of SWA induced by ketamine/xylazine anesthesia and compared their power and synchrony with wake state levels in mice. We further investigated the state-dependent changes in both gamma power and synchrony across primary motor and primary somatosensory cortical regions and their interconnected thalamic regions throughout anesthesia and recovery. As observed previously, gamma power was as high as during wake specifically during the ON state of SWA. However, the synchrony of this gamma activity between somatosensory-motor cortical regions was significantly reduced compared to the baseline wake state. In addition, the somatosensory-motor cortical synchrony of gamma oscillations was reduced and restored in an anesthetic state-dependent manner, reflecting the changing depth of anesthesia. Our results provide evidence that during anesthesia changes in long-range information integration between cortical regions might be more critical for changes in consciousness than changes in local gamma oscillatory power.

  3. Slow wave and REM sleep deprivation effects on explicit and implicit memory during sleep.

    Science.gov (United States)

    Casey, Sarah J; Solomons, Luke C; Steier, Joerg; Kabra, Neeraj; Burnside, Anna; Pengo, Martino F; Moxham, John; Goldstein, Laura H; Kopelman, Michael D

    2016-11-01

    It has been debated whether different stages in the human sleep cycle preferentially mediate the consolidation of explicit and implicit memories, or whether all of the stages in succession are necessary for optimal consolidation. Here we investigated whether the selective deprivation of slow wave sleep (SWS) or rapid eye movement (REM) sleep over an entire night would have a specific effect on consolidation in explicit and implicit memory tasks. Participants completed a set of explicit and implicit memory tasks at night, prior to sleep. They had 1 control night of undisturbed sleep and 2 experimental nights, during which either SWS or REM sleep was selectively deprived across the entire night (sleep conditions counterbalanced across participants). Polysomnography recordings quantified precisely the amount of SWS and REM sleep that occurred during each of the sleep conditions, and spindle counts were recorded. In the morning, participants completed the experimental tasks in the same sequence as the night before. SWS deprivation disrupted the consolidation of explicit memories for visuospatial information (ηp2 = .23), and both SWS (ηp2 = .53) and REM sleep (ηp2 = .52) deprivation adversely affected explicit verbal recall. Neither SWS nor REM sleep deprivation affected aspects of short-term or working memory, and did not affect measures of verbal implicit memory. Spindle counts did not correlate significantly with memory performance. These findings demonstrate the importance of measuring the sleep cycles throughout the entire night, and the contribution of both SWS and REM sleep to memory consolidation. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  4. Reduced Sodium Current in the Lateral Ventricular Wall Induces Inferolateral J-Waves.

    Science.gov (United States)

    Meijborg, Veronique M F; Potse, Mark; Conrath, Chantal E; Belterman, Charly N W; De Bakker, Jacques M T; Coronel, Ruben

    2016-01-01

    J-waves in inferolateral leads are associated with a higher risk for idiopathic ventricular fibrillation. We aimed to test potential mechanisms (depolarization or repolarization dependent) responsible for inferolateral J-waves. We hypothesized that inferolateral J-waves can be caused by regional delayed activation of myocardium that is activated late during normal conditions. Computer simulations were performed to evaluate how J-point elevation is influenced by reducing sodium current conductivity (GNa), increasing transient outward current conductivity (Gto), or cellular uncoupling in three predefined ventricular regions (lateral, anterior, or septal). Two pig hearts were Langendorff-perfused with selective perfusion with a sodium channel blocker of lateral or anterior/septal regions. Volume-conducted pseudo-electrocardiograms (ECG) were recorded to detect the presence of J-waves. Epicardial unipolar electrograms were simultaneously recorded to obtain activation times (AT). Simulation data showed that conduction slowing, caused by reduced sodium current, in lateral, but not in other regions induced inferolateral J-waves. An increase in transient outward potassium current or cellular uncoupling in the lateral zone elicited slight J-point elevations which did not meet J-wave criteria. Additional conduction slowing in the entire heart attenuated J-waves and J-point elevations on the ECG, because of masking by the QRS. Experimental data confirmed that conduction slowing attributed to sodium channel blockade in the left lateral but not in the anterior/septal ventricular region induced inferolateral J-waves. J-waves coincided with the delayed activation. Reduced sodium current in the left lateral ventricular myocardium can cause inferolateral J-waves on the ECG.

  5. Familial occurrence of inflammatory bowel disease

    DEFF Research Database (Denmark)

    Orholm, M; Munkholm, P; Langholz, E

    1991-01-01

    BACKGROUND AND METHODS: We assessed the familial occurrence of inflammatory bowel disease in Copenhagen County, where there has been a long-term interest in the epidemiology of such disorders. In 1987 we interviewed 662 patients in whom inflammatory bowel disease had been diagnosed before 1979, a...

  6. The State of Mechanical Bowel Preparation in Colorectal Surgery

    NARCIS (Netherlands)

    H.P. van 't Sant (Hans Pieter)

    2014-01-01

    markdownabstract__Abstract__ Surgical resection is the cornerstone of treatment for patients with colorectal cancer and has an important role in patients with inflammatory bowel disease or other benign bowel conditions requiring surgical treatment. Generally, restoration of bowel continuity

  7. Automatic Bowel Motility Evaluation Technique for Noncontact Sound Recordings

    Directory of Open Access Journals (Sweden)

    Ryunosuke Sato

    2018-06-01

    Full Text Available Information on bowel motility can be obtained via magnetic resonance imaging (MRIs and X-ray imaging. However, these approaches require expensive medical instruments and are unsuitable for frequent monitoring. Bowel sounds (BS can be conveniently obtained using electronic stethoscopes and have recently been employed for the evaluation of bowel motility. More recently, our group proposed a novel method to evaluate bowel motility on the basis of BS acquired using a noncontact microphone. However, the method required manually detecting BS in the sound recordings, and manual segmentation is inconvenient and time consuming. To address this issue, herein, we propose a new method to automatically evaluate bowel motility for noncontact sound recordings. Using simulations for the sound recordings obtained from 20 human participants, we showed that the proposed method achieves an accuracy of approximately 90% in automatic bowel sound detection when acoustic feature power-normalized cepstral coefficients are used as inputs to artificial neural networks. Furthermore, we showed that bowel motility can be evaluated based on the three acoustic features in the time domain extracted by our method: BS per minute, signal-to-noise ratio, and sound-to-sound interval. The proposed method has the potential to contribute towards the development of noncontact evaluation methods for bowel motility.

  8. Nonlinear modulation of ion acoustic waves in a magnetized plasma

    International Nuclear Information System (INIS)

    Bharuthram, R.; Shukla, P.K.

    1987-01-01

    The quasistatic plasma slow response to coherent ion acoustic waves in a magnetized plasma is considered. A multidimensional cubic nonlinear Schroedinger equation is derived. It is found that the ion acoustic waves remain modulationally stable against oblique perturbations

  9. SLOWNESS SURFACE CALCULATION FOR DIFFERENT MEDIA USING THE SYMBOLIC MATHEMATICS LANGUAGE MAPLE®

    Directory of Open Access Journals (Sweden)

    Piedrahita Carlos

    2004-06-01

    Full Text Available Starting from the equation in different media, we obtain the different type of waves that can exists in such media. The evaluation of the eigenvalues and eigenvectors let us construct the slowness surfaces. In general complex calculations case have to be made. In this work, routines were implemented in the symbolic language MAPLE® and the slowness surfaces were plotted. This work is relevant for the modelling of equivalent media that simulates natural fractured reservoirs, like those common in the Colombian foothills. It is important to understand the seismic response of this reservoirs for exploration of this areas.

  10. Improving LIGO calibration accuracy by tracking and compensating for slow temporal variations

    International Nuclear Information System (INIS)

    Tuyenbayev, D; Karki, S; Goetz, E; Izumi, K; Kissel, J S; Mendell, G; Savage, R L; Betzwieser, J; Kandhasamy, S; Cahillane, C; Weinstein, A J; Wade, M

    2017-01-01

    Calibration of the second-generation LIGO interferometric gravitational-wave detectors employs a method that uses injected periodic modulations to track and compensate for slow temporal variations in the differential length response of the instruments. These detectors utilize feedback control loops to maintain resonance conditions by suppressing differential arm length variations. We describe how the sensing and actuation functions of these servo loops are parameterized and how the slow variations in these parameters are quantified using the injected modulations. We report the results of applying this method to the LIGO detectors and show that it significantly reduces systematic errors in their calibrated outputs. (paper)

  11. Pregnancy outcome in inflammatory bowel disease

    DEFF Research Database (Denmark)

    Bortoli, A; Pedersen, N; Duricova, D

    2011-01-01

    Inflammatory bowel disease (IBD) frequently affects women during their reproductive years. Pregnancy outcome in women with IBD is well described, particularly in retrospective studies.......Inflammatory bowel disease (IBD) frequently affects women during their reproductive years. Pregnancy outcome in women with IBD is well described, particularly in retrospective studies....

  12. Daytime Ayahuasca administration modulates REM and slow-wave sleep in healthy volunteers.

    Science.gov (United States)

    Barbanoj, Manel J; Riba, Jordi; Clos, S; Giménez, S; Grasa, E; Romero, S

    2008-02-01

    Ayahuasca is a traditional South American psychoactive beverage and the central sacrament of Brazilian-based religious groups, with followers in Europe and the United States. The tea contains the psychedelic indole N,N-dimethyltryptamine (DMT) and beta-carboline alkaloids with monoamine oxidase-inhibiting properties that render DMT orally active. DMT interacts with serotonergic neurotransmission acting as a partial agonist at 5-HT(1A) and 5-HT(2A/2C) receptor sites. Given the role played by serotonin in the regulation of the sleep/wake cycle, we investigated the effects of daytime ayahuasca consumption in sleep parameters. Subjective sleep quality, polysomnography (PSG), and spectral analysis were assessed in a group of 22 healthy male volunteers after the administration of a placebo, an ayahuasca dose equivalent to 1 mg DMT kg(-1) body weight, and 20 mg d-amphetamine, a proaminergic drug, as a positive control. Results show that ayahuasca did not induce any subjectively perceived deterioration of sleep quality or PSG-measured disruptions of sleep initiation or maintenance, in contrast with d-amphetamine, which delayed sleep initiation, disrupted sleep maintenance, induced a predominance of 'light' vs 'deep' sleep and significantly impaired subjective sleep quality. PSG analysis also showed that similarly to d-amphetamine, ayahuasca inhibits rapid eye movement (REM) sleep, decreasing its duration, both in absolute values and as a percentage of total sleep time, and shows a trend increase in its onset latency. Spectral analysis showed that d-amphetamine and ayahuasca increased power in the high frequency range, mainly during stage 2. Remarkably, whereas slow-wave sleep (SWS) power in the first night cycle, an indicator of sleep pressure, was decreased by d-amphetamine, ayahuasca enhanced power in this frequency band. Results show that daytime serotonergic psychedelic drug administration leads to measurable changes in PSG and sleep power spectrum and suggest an

  13. Elastic Wave Control Beyond Band-Gaps: Shaping the Flow of Waves in Plates and Half-Spaces with Subwavelength Resonant Rods

    Directory of Open Access Journals (Sweden)

    Andrea Colombi

    2017-08-01

    Full Text Available In metamaterial science, local resonance and hybridization are key phenomena strongly influencing the dispersion properties; the metasurface discussed in this article created by a cluster of resonators, subwavelength rods, atop an elastic surface being an exemplar with these features. On this metasurface, band-gaps, slow or fast waves, negative refraction, and dynamic anisotropy can all be observed by exploring frequencies and wavenumbers from the Floquet–Bloch problem and by using the Brillouin zone. These extreme characteristics, when appropriately engineered, can be used to design and control the propagation of elastic waves along the metasurface. For the exemplar we consider, two parameters are easily tuned: rod height and cluster periodicity. The height is directly related to the band-gap frequency and, hence, to the slow and fast waves, while the periodicity is related to the appearance of dynamic anisotropy. Playing with these two parameters generates a gallery of metasurface designs to control the propagation of both flexural waves in plates and surface Rayleigh waves for half-spaces. Scalability with respect to the frequency and wavelength of the governing physical laws allows the application of these concepts in very different fields and over a wide range of lengthscales.

  14. Transient small-bowel intussusception in children on CT

    International Nuclear Information System (INIS)

    Strouse, Peter J.; DiPietro, Michael A.; Saez, Fermin

    2003-01-01

    To determine the frequency and significance of small-bowel intussusception identified in children on CT. All abdomen CT reports between July 1995 and April 2002 were reviewed to identify patients with small-bowel intussusception. Intussusceptions were identified as an intraluminal mass with a characteristic layered appearance and/or continuity with adjacent mesenteric fat. Ileocolic intussusceptions and intussusceptions related to feeding tubes were excluded. Imaging studies and medical records were reviewed. Twenty-five pediatric patients (16 boys, 9 girls; mean age 11.2 years) were identified with small-bowel intussusception on CT. No patient had a persistent intussusception requiring surgery. Fourteen had limited immediate repeat CT images as part of the same examination, ten of which demonstrated resolution of the CT abnormality. Follow-up CT [n=13 (6 within 24 h)], ultrasound (n=3), small-bowel follow-through (n=4) and surgery (n=3) showed no intussusception. In four patients with persistent symptoms, underlying pathology was identified requiring treatment (giardiasis, 2; small-bowel inflammation/strictures, 1; abscess and partial small-bowel obstruction after perforated appendicitis, 1). In 21 other patients, direct correlation of symptoms to CT abnormality was absent or questionable, no treatment was required, and there was no clinical or imaging evidence of persistence or recurrence. Most small-bowel intussusceptions identified in children by CT are transient and of no clinical significance. (orig.)

  15. Reduction of nocturnal slow-wave activity affects daytime vigilance lapses and memory encoding but not reaction time or implicit learning.

    Science.gov (United States)

    Van Der Werf, Ysbrand D; Altena, Ellemarije; Vis, José C; Koene, Teddy; Van Someren, Eus J W

    2011-01-01

    Total sleep deprivation in healthy subjects has a profound effect on the performance on tasks measuring sustained attention or vigilance. We here report how a selective disruption of deep sleep only, that is, selective slow-wave activity (SWA) reduction, affects the performance of healthy well-sleeping subjects on several tasks: a "simple" and a "complex" vigilance task, a declarative learning task, and an implicit learning task despite unchanged duration of sleep. We used automated electroencephalogram (EEG) dependent acoustic feedback aimed at selective interference with-and reduction of-SWA. In a within-subject repeated measures crossover design, performance on the tasks was assessed in 13 elderly adults without sleep complaints after either SWA-reduction or after normal sleep. The number of vigilance lapses increased as a result of SWA reduction, irrespective of the type of vigilance task. Recognition on the declarative memory task was also affected by SWA reduction, associated with a decreased activation of the right hippocampus on encoding (measured with fMRI) suggesting a weaker memory trace. SWA reduction, however, did not affect reaction time on either of the vigilance tasks or implicit memory task performance. These findings suggest a specific role of slow oscillations in the subsequent daytime ability to maintain sustained attention and to encode novel declarative information but not to maintain response speed or to build implicit memories. Of particular interest is that selective SWA reduction can mimic some of the effects of total sleep deprivation, while not affecting sleep duration. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Dissipation of Alfven Waves at Fluid Scale through Parametric Decay Instabilities in Low-beta Turbulent Plasma

    Science.gov (United States)

    Fu, X.; Li, H.; Guo, F.; Li, X.; Roytershteyn, V.

    2017-12-01

    The solar wind is a turbulent magnetized plasma extending from the upper atmosphere of the sun to the edge of the heliosphere. It carries charged particles and magnetic fields originated from the Sun, which have great impact on the geomagnetic environment and human activities in space. In such a magnetized plasma, Alfven waves play a crucial role in carrying energy from the surface of the Sun, injecting into the solar wind and establishing power-law spectra through turbulent energy cascades. On the other hand, in compressible plasmas large amplitude Alfven waves are subject to a parametric decay instability (PDI) which converts an Alfven wave to another counter-propagating Alfven wave and an ion acoustic wave (slow mode). The counter-propagating Alfven wave provides an important ingredient for turbulent cascade, and the slow-mode wave provides a channel for solar wind heating in a spatial scale much larger than ion kinetic scales. Growth and saturation of PDI in quiet plasma have been intensively studied using linear theory and nonlinear simulations in the past. Here using 3D hybrid simulations, we show that PDI is still effective in turbulent low-beta plasmas, generating slow modes and causing ion heating. Selected events in WIND data are analyzed to identify slow modes in the solar wind and the role of PDI, and compared with our simulation results. We also investigate the validity of linear Vlasov theory regarding PDI growth and slow mode damping in turbulent plasmas. Since PDI favors low plasma beta, we expect to see more evidence of PDI in the solar wind close to the Sun, especially from the upcoming NASA's Parker Solar Probe mission which will provide unprecedented wave and plasma data as close as 8.5 solar radii from the Sun.

  17. SCALAR AND VECTOR NONLINEAR DECAYS OF LOW-FREQUENCY ALFVÉN WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, J. S.; Wu, D. J. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Voitenko, Y.; De Keyser, J., E-mail: js_zhao@pmo.ac.cn [Solar-Terrestrial Centre of Excellence, Space Physics Division, Belgian Institute for Space Aeronomy, Ringlaan 3 Avenue Circulaire, B-1180 Brussels (Belgium)

    2015-02-01

    We found several efficient nonlinear decays for Alfvén waves in the solar wind conditions. Depending on the wavelength, the dominant decay is controlled by the nonlinearities proportional to either scalar or vector products of wavevectors. The two-mode decays of the pump MHD Alfvén wave into co- and counter-propagating product Alfvén and slow waves are controlled by the scalar nonlinearities at long wavelengths ρ{sub i}{sup 2}k{sub 0⊥}{sup 2}<ω{sub 0}/ω{sub ci} (k {sub 0} is wavenumber perpendicular to the background magnetic field, ω{sub 0} is frequency of the pump Alfvén wave, ρ {sub i} is ion gyroradius, and ω {sub ci} is ion-cyclotron frequency). The scalar decays exhibit both local and nonlocal properties and can generate not only MHD-scale but also kinetic-scale Alfvén and slow waves, which can strongly accelerate spectral transport. All waves in the scalar decays propagate in the same plane, hence these decays are two-dimensional. At shorter wavelengths, ρ{sub i}{sup 2}k{sub 0⊥}{sup 2}>ω{sub 0}/ω{sub ci}, three-dimensional vector decays dominate generating out-of-plane product waves. The two-mode decays dominate from MHD up to ion scales ρ {sub i} k {sub 0} ≅ 0.3; at shorter scales the one-mode vector decays become stronger and generate only Alfvén product waves. In the solar wind the two-mode decays have high growth rates >0.1ω{sub 0} and can explain the origin of slow waves observed at kinetic scales.

  18. Diet and risk of inflammatory bowel disease

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Olsen, Anja; Carbonnel, Franck

    2012-01-01

    Background: A better understanding of the environmental factors leading to inflammatory bowel disease should help to prevent occurrence of the disease and its relapses. Aim: To review current knowledge on dietary risk factors for inflammatory bowel disease. Methods: The PubMed, Medline and Cochrane...... Library were searched for studies on diet and risk of inflammatory bowel disease. Results: Established non-diet risk factors include family predisposition, smoking, appendectomy, and antibiotics. Retrospective case–control studies are encumbered with methodological problems. Prospective studies...... on European cohorts, mainly including middle-aged adults, suggest that a diet high in protein from meat and fish is associated with a higher risk of inflammatory bowel disease. Intake of the n-6 polyunsaturated fatty acid linoleic acid may confer risk of ulcerative colitis, whereas n-3 polyunsaturated fatty...

  19. Study of the stability of the stationary wave of nuclear fission

    International Nuclear Information System (INIS)

    Khotyanintsev, V.N.; Aksenov, A.V.; Khotyanintseva, E.N.; Pavlovich, V.N.

    2014-01-01

    Stability of the stationary wave of nuclear burning in fast reactor with uranium-plutonium fuel chain is investigated. The reactor model including 1-D diffusion equation in one-group approximation for neutron flux density and kinetic equations for nuclear densities describes slow evolution of nuclear densities followed by neutron flux. New analytical approach was proposed, which is based on the approximation of small wave velocity of the stationary wave. We obtain so-called wave velocity characteristic of the reactor which is the dependence of wave velocity to the effective absorber concentration. We show that due to instability of long-living 241 Pu a turning point and lower branch of stationary solutions appear. Numerical solution of the time dependent problem proves that the solutions of the lower branch are unstable. Thus, the turning point of the velocity characteristic corresponds to the lower margin of possible wave velocities of nuclear fission waves of the steady shape. At the same time the solutions of the upper branch are stable with respect to slow evolution of nuclear densities

  20. Enhancing the sensitivity of slow light MZI biosensors through multi-hole defects

    Science.gov (United States)

    Qin, Kun; Zhao, Yiliang; Hu, Shuren; Weiss, Sharon M.

    2018-02-01

    We demonstrate enhanced detection sensitivity of a slow light Mach-Zehnder interferometer (MZI) sensor by incorporating multi-hole defects (MHDs). Slow light MZI biosensors with a one-dimensional photonic crystal in one arm have been previously shown to improve the performance of traditional MZI sensors based on the increased lightmatter interaction that takes place in the photonic crystal region of the structure. Introducing MHDs in the photonic crystal region increases the available surface area for molecular attachment and further increases the enhanced lightmatter interaction capability of slow light MZIs. The MHDs allow analyte to interact with a greater fraction of the guided wave in the MZI. For a slow light MHD MZI sensor with a 16 μm long sensing arm, a bulk sensitivity of 151,000 rad/RIU-cm is demonstrated experimentally, which is approximately two-fold higher than our previously reported slow light MZI sensors and thirteen-fold higher than traditional MZI biosensors with millimeter length sensing regions. For the label-free detection of nucleic acids, the slow light MZI with MHDs also exhibits a two-fold sensitivity improvement in experiment compared to the slow light MZI without MHDs. Because the detection sensitivity of slow light MHD MZIs scales with the length of the sensing arm, the tradeoff between detection limit and device size can be appropriately mitigated for different applications. All experimental results presented in this work are in good agreement with finite difference-time domain-calculations. Overall, the slow light MZI biosensors with MHDs are a promising platform for highly sensitive and multiplexed lab-on-chip systems.

  1. The impact of laxative use upon symptoms in patients with proven slow transit constipation

    Directory of Open Access Journals (Sweden)

    Dinning Phil G

    2011-11-01

    Full Text Available Abstract Background Constipation severity is often defined by symptoms including feelings of complete evacuation, straining, stool frequency and consistency. These descriptors are mostly obtained in the absence of laxative use. For many constipated patients laxative usage is ubiquitous and long standing. Our aim was to determine the impact of laxative use upon the stereotypic constipation descriptors. Methods Patients with confirmed slow transit constipation completed 3-week stool diaries, detailing stool frequency and form, straining, laxative use and pain and bloating scores. Each diary day was classified as being under laxative affect (laxative affected days or not (laxative unaffected days. Unconditional logistic regression was used to assess the affects of laxatives on constipation symptoms. Results Ninety four patients with scintigraphically confirmed slow transit constipation were enrolled in the study. These patients reported a stool frequency of 5.6 ± 4.3 bowel motions/week, only 21 patients reported P P Conclusions The reporting of frequent and loose stools with abdominal pain and/or bloating is common in patients with slow transit constipation. While laxative use is a significant contributor to altering stool frequency and form, laxatives have no apparent affect on pain or bloating or upon a patients feeling of complete evacuation. These factors need to be taken into account when using constipation symptoms to define this population.

  2. How to turn gravity waves into Alfven waves and other such tricks

    International Nuclear Information System (INIS)

    Newington, Marie E; Cally, Paul S

    2011-01-01

    Recent observations of travelling gravity waves at the base of the chromosphere suggest an interplay between gravity wave propagation and magnetic field. Our aims are: to explain the observation that gravity wave flux is suppressed in magnetic regions; to understand why we see travelling waves instead of standing waves; and to see if gravity waves can undergo mode conversion and couple to Alfven waves in regions where the plasma beta is of order unity. We model gravity waves in a VAL C atmosphere, subject to a uniform magnetic field of various orientations, considering both adiabatic and radiatively damped propagation. Results indicate that in the presence of a magnetic field, the gravity wave can propagate as a travelling wave, with the magnetic field orientation playing a crucial role in determining the wave character. For the majority of magnetic field orientations, the gravity wave is reflected at low heights as a slow magneto-acoustic wave, explaining the observation of reduced flux in magnetic regions. In a highly inclined magnetic field, the gravity wave undergoes mode conversion to either field guided acoustic waves or Alfven waves. The primary effect of incorporating radiative damping is a reduction in acoustic and magnetic fluxes measured at the top of the integration region. By demonstrating the mode conversion of gravity waves to Alfven waves, this work identifies a possible pathway for energy transport from the solar surface to the upper atmosphere.

  3. Differential diagnosis of mechanical bowel obstruction and paralytic ileus on CT features

    International Nuclear Information System (INIS)

    Jeon, Yong Sun; Kim, Mi Young; Suh, Chang Hae; Chung, Won Kyun; Kim, Kyung Rae; Kim, Kyung Kook; Shin, Yong Woon

    1997-01-01

    To evaluate CT findings for the differential diagnosis of mechanical bowel obstruction and paralytic ileus. Without information relating to clinical or operative findings, we retrospectively analyzed the CT scans of 24 patients with mechanical bowel obstruction and 19 patients with paralytic ileus. Final diagnosis was confirmed by operation (n=26), or by clinical symptoms, radiologic findings and follow-up study CT findings were obtained:1) the diameter of the most dilated part of the small bowel, and the thickness and enhancing pattern of the dilated small bowel wall;2) the diameter of the most dilated part of the descending colon and the ratio of the diameter of the small bowel to that of the descending colon;3) the number of transitional zones, length and thickness and 4) associated ascites and its location. The mean diameters of the most dilated part of the small bowel in mechanical bowel obstruction and paralytic ileus were 3.6cm and 2.9cm, respectively. The diameter of the small bowel in mechanical bowel obstruction was significantly greater than in paralytic ileus(p<.05). The mean thickness of dilated small bowel wall was 4.0mm in mechanical bowel obstruction and 2.4mm in paralytic ileus, and target-like enhancement was prominent in mechanical bowel obstruction(46%)(p<.05). The mean diameter of the most dilated part of the descending colon was not significantly different to that of the most dilated part of the small bowel, but the ratio of the diameter of the small bowel to that of the colon was 2.9 in mechanical bowel obstruction and 1.9 in paralytic ileus, respectively, which was statistically significant(p<.05). A transitional zone was seen in 23 cases(96%) of mechanical bowel obstruction and in nine (47%) of paralytic ileus. In mechanical bowel obstruction, mean transitional zone length was 2cm, shorter than that of paralytic ileus(3.4cm)(p<.05) The thickness of transitional zone and the presence of ascites and its locations were not significantly

  4. Surgical treatment of bowel occlusion as late radiation effect

    International Nuclear Information System (INIS)

    Moeschl, P.; Miholic, J.; Wolner, E.

    1989-01-01

    67 patients were operated for intestinal complications following radiotherapy. The lesions were located in the small bowel (n = 41) and in the sigmoid colon/rectum (n = 33). 98.5% of the patients were females, the most frequent cause for irradiation being ovarian cancer. Bowel stenosis with resultant chronic or acute ileus was the most frequent indication for operation. Percutaneous irradiation resulted in a significantly higher proportion of small bowel lesions (77%, p = 0.001), whilst endocavitary irradiation was followed in 67% of cases by colorectal lesions. Different application modality of irradiation also resulted in completely different symptoms for small and large bowel lesions. The operative mortality was 9.5%. Peritonitis following anastomotic leakage was the cause of death in 6 of 7 cases. In the treatment of small bowel ileus mortality following bowel resection (9%, one of 11 cases) was comparable to that of the bypass operation (6%, one of 18 cases). Both operation methods seem to be justified. Single-layer anastomosis resulted in zero mortality (21 cases) for ileus operation compared with 19% mortality (16 cases) in double-layer anastomosis and should be prefered for operations on the irradiated bowel. (author)

  5. Efficacy of bowel cancer appeals for promoting physical activity.

    Science.gov (United States)

    Jalleh, Geoffrey; Donovan, Robert J; Slevin, Terry; Dixon, Helen

    2005-08-01

    To investigate the potential efficacy of bowel cancer prevention messages in increasing intentions to be more physically active. A convenience sample of 281 physically inactive persons aged 30-60 years was recruited in the Perth city centre and randomly assigned to a bowel cancer and physical activity message or a heart disease and physical activity message. After reading a booklet containing information about physical activity and its link either to bowel cancer (n = 141) or cardiovascular disease (n = 140), respondents filled in a self-completion questionnaire. The main response measures were impact on intentions to be more physically active, and perceived believability and relevance of the message. Perceived believability of the message was high in both conditions. Perceived personal relevance of the message was substantially lower in the bowel cancer than the cardiovascular disease condition. Overall, the cardiovascular disease condition achieved somewhat higher behavioural intentions than the bowel cancer condition. The finding that two in three respondents in the bowel cancer condition had increased intention to increase their level of physical activity provides support for the potential efficacy of promoting physical activity in reducing the risk of bowel cancer.

  6. GEODYNAMIC WAVES AND GRAVITY

    Directory of Open Access Journals (Sweden)

    A. V. Vikulin

    2014-01-01

    Full Text Available  Gravity phenomena related to the Earth movements in the Solar System and through the Galaxy are reviewed. Such movements are manifested by geological processes on the Earth and correlate with geophysical fields of the Earth. It is concluded that geodynamic processes and the gravity phenomena (including those of cosmic nature are related.  The state of the geomedium composed of blocks is determined by stresses with force moment and by slow rotational waves that are considered as a new type of movements [Vikulin, 2008, 2010]. It is shown that the geomedium has typical rheid properties [Carey, 1954], specifically an ability to flow while being in the solid state [Leonov, 2008]. Within the framework of the rotational model with a symmetric stress tensor, which is developed by the authors [Vikulin, Ivanchin, 1998; Vikulin et al., 2012a, 2013], such movement of the geomedium may explain the energy-saturated state of the geomedium and a possibility of its movements in the form of vortex geological structures [Lee, 1928]. The article discusses the gravity wave detection method based on the concept of interactions between gravity waves and crustal blocks [Braginsky et al., 1985]. It is concluded that gravity waves can be recorded by the proposed technique that detects slow rotational waves. It is shown that geo-gravitational movements can be described by both the concept of potential with account of gravitational energy of bodies [Kondratyev, 2003] and the nonlinear physical acoustics [Gurbatov et al., 2008]. Based on the combined description of geophysical and gravitational wave movements, the authors suggest a hypothesis about the nature of spin, i.e. own moment as a demonstration of the space-time ‘vortex’ properties.  

  7. IRRITATED BOWEL SYNDROME IN CHILDREN

    Directory of Open Access Journals (Sweden)

    V. F. Privorotskiy

    2012-01-01

    Full Text Available Irritated bowel syndrome is a significant and underestimated problem in childhood. This condition is not so good studied in pediatrics in comparison with adult practice. Pediatricians often diagnosed this disease in infants and young children without proper reasons. The authors analyze current opinions about etiology and pathogenesis, clinical presentation, diagnosticsand treatment of irritated bowel syndrome in children. An emphasis is made on diagnostic criteria, which allow suggesting and confirming the diagnosis.

  8. Diet in irritable bowel syndrome

    OpenAIRE

    El-Salhy, Magdy; Gundersen, Doris Irene

    2015-01-01

    Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder that is characterized by intermittent abdominal pain/discomfort, altered bowel habits and abdominal bloating/distension. This review aimed at presenting the recent developments concerning the role of diet in the pathophysiology and management of IBS. There is no convincing evidence that IBS patients suffer from food allergy/intolerance, and there is no evidence that gluten causes the debated new diagnosis of non-coel...

  9. Scattered P'P' waves observed at short distances

    Science.gov (United States)

    Earle, Paul S.; Rost, Sebastian; Shearer, Peter M.; Thomas, Christine

    2011-01-01

    We detect previously unreported 1 Hz scattered waves at epicentral distances between 30° and 50° and at times between 2300 and 2450 s after the earthquake origin. These waves likely result from off-azimuth scattering of PKPbc to PKPbc in the upper mantle and crust and provide a new tool for mapping variations in fine-scale (10 km) mantle heterogeneity. Array beams from the Large Aperture Seismic Array (LASA) clearly image the scattered energy gradually emerging from the noise and reaching its peak amplitude about 80 s later, and returning to the noise level after 150 s. Stacks of transverse versus radial slowness (ρt, ρr) show two peaks at about (2, -2) and (-2,-2) s/°, indicating the waves arrive along the major arc path (180° to 360°) and significantly off azimuth. We propose a mantle and surface PKPbc to PKPbc scattering mechanism for these observations because (1) it agrees with the initiation time and distinctive slowness signature of the scattered waves and (2) it follows a scattering path analogous to previously observed deep-mantle PK•KP scattering (Chang and Cleary, 1981). The observed upper-mantle scattered waves and PK•KP waves fit into a broader set of scattered waves that we call P′•d•P′, which can scatter from any depth, d, in the mantle.

  10. Frequent Bowel Movements

    Science.gov (United States)

    ... bowel disease (IBD). Centers for Disease Control and Prevention. https://www.cdc.gov/ibd/what-is-IBD.htm. Accessed Nov. 15, 2017. Hyperthyroidism (Overactive thyroid). National Institute of Diabetes and Digestive ...

  11. Women's experiences of living with neurogenic bladder and bowel after spinal cord injury: life controlled by bladder and bowel.

    Science.gov (United States)

    Nevedal, Andrea; Kratz, Anna L; Tate, Denise G

    2016-01-01

    Neurogenic bladder and bowel (NBB) is a chronic condition hindering the functioning and quality of life (QOL) of people with spinal cord injury (SCI). NBB research has focused on men with SCI leaving unanswered questions about women's experiences of living with NBB. The purpose of this study was to identify and describe women's experiences of living with SCI and NBB. Secondary analysis of semi-structured interviews from a larger qualitative study of women with SCI (N = 50) was carried out. Transcripts were coded for bowel and bladder content. Pile-sorting techniques were used to identify emergent themes related to NBB. Meta-themes were categorized under the International Classification of Functioning, Disability and Health. Bladder and bowel topics were spontaneously discussed by 46 out of 50 study participants suggesting the salience of this issue for women with SCI. We identified 6 meta-themes: life controlled by bladder and bowel, bladder and bowel accidents, women's specific challenges, life course disruption, bladder and bowel medical management, and finding independence. Findings describe concerns, strategies, and the detrimental impact of NBB in the lives of women with SCI. Findings inform policy makers, health care and rehabilitation professionals to improve accessibility and quality of life for women with NBB. Women with spinal cord injury (SCI) reported gender specific challenges to living with neurogenic bladder and bowel (NBB). Interventions designed for women with SCI can address these problems and provide recommendations for prevention and treatment. Women described the detrimental impact of NBB on life course expectations, emotional, social, physical health, and quality of life domains. Psychosocial and educational programs can be developed to address these challenges and improve overall quality of life. Recommendations for special treatment and policy considerations are needed to maximize women's independence and health while living with NBB

  12. Prospective trial of aggressive postoperative bowel stimulation following radical hysterectomy.

    Science.gov (United States)

    Fanning, J; Yu-Brekke, S

    1999-06-01

    Postoperative traditional feeding protocols are not based on scientific studies, but rather on anecdotal evidence. We present the first prospective trial of aggressive postoperative bowel stimulation following radical hysterectomy in an attempt to determine its effect on the length of hospital stay. Twenty consecutive patients undergoing radical hysterectomy were entered onto a prospective trial of aggressive postoperative bowel stimulation, which consisted of 30 cc milk of magnesia p.o. b.i.d. starting on postoperative day 1 and biscolic suppositories q.d. starting on day 2. A clear liquid diet was begun following flatus or bowel movement and patients were discharged 12 h after tolerating a clear liquid diet. Diet was slowly advanced at home. Median time to flatus was 3 days, bowel movement 3 days, and clear liquid diet 3 days. Median time to discharge was 4 days. No patients developed ileus or bowel obstructions and there were no readmissions for bowel complications. Our median time to discharge of 4 days represents a 50% reduction in hospital stay compared to our previous prospective study using traditional postoperative bowel management (8 days), which was statistically significant at P = 0.001. Aggressive bowel stimulation with milk of magnesia and biscolic suppositories resulted in early return of bowel function and early discharge with no noticeable complications. Copyright 1999 Academic Press.

  13. The Direct Digital Modulation of Traveling Wave Tubes

    Science.gov (United States)

    Radhamohan, Ranjan S.

    2004-01-01

    Traveling wave tube (TWT) technology, first described by Rudolf Kompfner in the early 1940s, has been a key component of space missions from the earliest communication satellites in the 1960s to the Cassini probe today. TWTs are essentially signal amplifiers that have the special capability of operating at microwave frequencies. The microwave frequency range, which spans from approximately 500 MHz to 300 GHz, is shared by many technologies including cellular phones, satellite television, space communication, and radar. TWT devices are superior in reliability, weight, and efficiency to solid-state amplifiers at the high power and frequency levels required for most space missions. TWTs have three main components -an electron gun, slow wave structure, and collector. The electron gun generates an electron beam that moves along the length of the tube axis, inside of the slow wave circuit. At the same time, the inputted signal is slowed by its travel through the coils of the helical slow wave circuit. The interaction of the electron beam and this slowed signal produces a transfer of kinetic energy to the signal, and in turn, amplification. At the end of its travel, the spent electron beam moves into the collector where its remaining energy is dissipated as heat or harnessed for reuse. TWTs can easily produce gains in the tens of decibels, numbers that are suitable for space missions. To date, however, TWTs have typically operated at fixed levels of gain. This gain is determined by various, unchanging, physical factors of the tube. Traditionally, to achieve varying gain, an input signal s amplitude has had to first be modulated by a separate device before being fed into the TWT. This is not always desirable, as significant distortion can occur in certain situations. My mentor, Mr. Dale Force, has proposed an innovative solution to this problem called direct digital modulation . The testing and implementation of this solution is the focus of my summer internship. The

  14. Non-invasive algorithm for bowel motility estimation using a back-propagation neural network model of bowel sounds

    Directory of Open Access Journals (Sweden)

    Song Chul-Gyu

    2011-08-01

    Full Text Available Abstract Background Radiological scoring methods such as colon transit time (CTT have been widely used for the assessment of bowel motility. However, these radiograph-based methods need cumbersome radiological instruments and their frequent exposure to radiation. Therefore, a non-invasive estimation algorithm of bowel motility, based on a back-propagation neural network (BPNN model of bowel sounds (BS obtained by an auscultation, was devised. Methods Twelve healthy males (age: 24.8 ± 2.7 years and 6 patients with spinal cord injury (6 males, age: 55.3 ± 7.1 years were examined. BS signals generated during the digestive process were recorded from 3 colonic segments (ascending, descending and sigmoid colon, and then, the acoustical features (jitter and shimmer of the individual BS segment were obtained. Only 6 features (J1, 3, J3, 3, S1, 2, S2, 1, S2, 2, S3, 2, which are highly correlated to the CTTs measured by the conventional method, were used as the features of the input vector for the BPNN. Results As a results, both the jitters and shimmers of the normal subjects were relatively higher than those of the patients, whereas the CTTs of the normal subjects were relatively lower than those of the patients (p k-fold cross validation, the correlation coefficient and mean average error between the CTTs measured by a conventional radiograph and the values estimated by our algorithm were 0.89 and 10.6 hours, respectively. Conclusions The jitter and shimmer of the BS signals generated during the peristalsis could be clinically useful for the discriminative parameters of bowel motility. Also, the devised algorithm showed good potential for the continuous monitoring and estimation of bowel motility, instead of conventional radiography, and thus, it could be used as a complementary tool for the non-invasive measurement of bowel motility.

  15. Primary small bowel anastomosis in generalised peritonitis

    NARCIS (Netherlands)

    deGraaf, JS; van Goor, Harry; Bleichrodt, RP

    Objective: To find out if primary small bowel anastomosis of the bowel is safe in patients with generalised peritonitis who are treated by planned relaparotomies. Design: Retrospective study. Setting: University hospital, The Netherlands. Subjects. 10 Patients with generalised purulent peritonitis

  16. Simulation of collective ion acceleration in a slow cyclotron beam mode

    International Nuclear Information System (INIS)

    Faehl, R.J.; Shanahan, W.R.; Godfrey, B.B.

    1979-01-01

    The use of slow cyclotron beam waves is examined as a means of accelerating ions in intense relativistic electron beams. Field magnitudes of between 10 5 -and 10 6 V/cm seem achievable in the near term, and while these will never reach the levels of beam front mechanisms, such as virtual cathodes, they will easily exceed conventional ion acceleration sources

  17. Endometriosis: A Rare Cause of Large Bowel Obstruction

    Directory of Open Access Journals (Sweden)

    Gonçalo Alexandrino

    2017-10-01

    Full Text Available Large bowel obstruction can result in significant morbidity and mortality, especially in cases of acute complete obstruction. There are many possible causes, the most common in adults being colorectal cancer. Endometriosis is a benign disease, and the most affected extragenital location is the bowel, especially the rectosigmoid junction. However, transmural involvement and acute occlusion are very rare events. We report an exceptional case of acute large bowel obstruction as the initial presentation of endometriosis. The differential diagnosis of colorectal carcinoma may be challenging, and this case emphasizes the need to consider intestinal endometriosis in females at a fertile age presenting with gastrointestinal symptoms and an intestinal mass causing complete large bowel obstruction.

  18. Dynamics of an atomic wave packet in a standing-wave cavity field: A cavity-assisted single-atom detection

    International Nuclear Information System (INIS)

    Chough, Young-Tak; Nha, Hyunchul; Kim, Sang Wook; An, Kyungwon; Youn, Sun-Hyun

    2002-01-01

    We investigate the single-atom detection system using an optical standing-wave cavity, from the viewpoint of the quantized center-of-mass motion of the atomic wave packet. We show that since the atom-field coupling strength depends upon the overlap integral of the atomic wave packet and the field mode function, the effect of the wave-packet spreading via the momentum exchange process brings about a significant effect in the detection efficiency. We find that, as a result, the detection efficiency is not sensitive to the individual atomic trajectory for reasonably slow atoms. We also address an interesting phenomenon of the atomic wave-packet splitting occurring when an atom passes through a node of the cavity field

  19. A cross-cultural perspective on irritable bowel syndrome.

    Science.gov (United States)

    Gerson, Charles D; Gerson, Mary-Joan

    2010-01-01

    Irritable bowel syndrome is a functional gastrointestinal illness, defined by symptoms. Irritable bowel syndrome has been described as a biopsychosocial condition, in which colonic dysfunction is affected by psychological and social factors. As a result of this unusual constellation, irritable bowel syndrome may be subject to cultural variables that differ in different parts of the globe. In this article, we describe some of the ways in which irritable bowel syndrome may be experienced differently, depending on local belief systems, psychological pressures, acceptance or resistance to a mind-body paradigm, and breakdown in support or relationship structure. Examples are given in which irritable bowel syndrome investigators from countries around the world describe various aspects of the syndrome that may affect the illness experience of their patients. We describe our own research studies that have demonstrated possible adverse effects on disease severity from relationship conflict, attribution of symptoms to physical rather than emotional cause, and the belief that irritable bowel syndrome is enduring and mysterious. Also described is our finding that symptom patterns may differ significantly between different geographic locations. Finally, we discuss the importance of "cultural competence" on the part of healthcare professionals in regard to caring for patients of diverse cultural backgrounds. © 2010 Mount Sinai School of Medicine.

  20. Conformal invariance and the four point scalar correlator in slow-roll inflation

    International Nuclear Information System (INIS)

    Ghosh, Archisman; Kundu, Nilay; Raju, Suvrat; Trivedi, Sandip P.

    2014-01-01

    We calculate the four point correlation function for scalar perturbations in the canonical model of slow-roll inflation. We work in the leading slow-roll approximation where the calculation can be done in de Sitter space. Our calculation uses techniques drawn from the AdS/CFT correspondence to find the wave function at late times and then calculate the four point function from it. The answer we get agrees with an earlier result in the literature, obtained using different methods. Our analysis reveals a subtlety with regard to the Ward identities for conformal invariance, which arises in de Sitter space and has no analogue in AdS space. This subtlety arises because in de Sitter space the metric at late times is a genuine degree of freedom, and hence to calculate correlation functions from the wave function of the Universe at late times, one must fix gauge completely. The resulting correlators are then invariant under a conformal transformation accompanied by a compensating coordinate transformation which restores the gauge.

  1. Evaluation of bowel distension and bowel wall visualization according to patient positions during administration of oral contrast media for CT enterography.

    Science.gov (United States)

    Lee, Seul Bi; Kim, Seung Ho; Son, Jung Hee; Baik, Ji Yeon

    2017-12-01

    To compare small bowel distension and bowel wall visualization among three different patients' positions (supine, sitting and right decubitus) during administration of oral contrast media in preparation for CT enterography (CTE). A total of 150 consecutive patients (104 males and 46 females; mean age 34.6 years, range 15-78 years) who were scheduled to undergo CTE were recruited. Patients were randomly allocated into the three position groups during oral contrast media administration, and there were 50 patients in each group. Two blinded radiologists independently scored the luminal distension and visualization of the bowel wall using a continuous 5-point scale (1: worst and 5: best) at the jejunum and ileum. The Mann-Whitney U test was used to evaluate differences between any two groups among the three positions for bowel distension and wall visualization. For ileal distension, the supine and sitting positions performed better than the right decubitus position [for reader 1, mean: 3.4/3.2/2.9 (hereafter, supine/sitting/right decubitus in order), p = 0.002/0.033; for reader 2, 3.3/3.0/2.6, p 0.05, respectively). For bowel wall visualization, the supine and sitting positions were superior to the right decubitus position for the ileum when scored by one reader (4.0/3.8/3.4, p = 0.001/0.015). Supine and sitting positions during the administration of oral contrast media provided better ileal distension than the right decubitus position in obtaining CTE. Advances in knowledge: The performance of CTE largely depends on adequate luminal distension and wall visualization. As the terminal ileum is the predominant site of small bowel pathology for inflammatory bowel disease, the supine or sitting position would be preferable for patients who are suspected of having small bowel pathology.

  2. Mechanical bowel preparation for elective colorectal surgery

    DEFF Research Database (Denmark)

    Güenaga, Katia F; Matos, Delcio; Wille-Jørgensen, Peer

    2011-01-01

    The presence of bowel contents during colorectal surgery has been related to anastomotic leakage, but the belief that mechanical bowel preparation (MBP) is an efficient agent against leakage and infectious complications is based on observational data and expert opinions only.An enema before...

  3. Seismic shear waves as Foucault pendulum

    Science.gov (United States)

    Snieder, Roel; Sens-Schönfelder, Christoph; Ruigrok, Elmer; Shiomi, Katsuhiko

    2016-03-01

    Earth's rotation causes splitting of normal modes. Wave fronts and rays are, however, not affected by Earth's rotation, as we show theoretically and with observations made with USArray. We derive that the Coriolis force causes a small transverse component for P waves and a small longitudinal component for S waves. More importantly, Earth's rotation leads to a slow rotation of the transverse polarization of S waves; during the propagation of S waves the particle motion behaves just like a Foucault pendulum. The polarization plane of shear waves counteracts Earth's rotation and rotates clockwise in the Northern Hemisphere. The rotation rate is independent of the wave frequency and is purely geometric, like the Berry phase. Using the polarization of ScS and ScS2 waves, we show that the Foucault-like rotation of the S wave polarization can be observed. This can affect the determination of source mechanisms and the interpretation of observed SKS splitting.

  4. Suppression of lower hybrid wave coupling due to the ponderomotive force

    International Nuclear Information System (INIS)

    Wilson, J.R.; Wong, K.L.

    1980-04-01

    The coupling efficiency from a slow-wave structure to lower hybrid waves is investigated experimentally. At moderate electric field strengths large edge density changes are observed. Wave trajectory modifications and departure from linear coupling are observed consistent with these changes and in good agreement with a simple nonlinear theory that includes the ponderomotive force

  5. Effects of MHD slow shocks propagating along magnetic flux tubes in a dipole magnetic field

    Directory of Open Access Journals (Sweden)

    N. V. Erkaev

    2002-01-01

    Full Text Available Variations of the plasma pressure in a magnetic flux tube can produce MHD waves evolving into shocks. In the case of a low plasma beta, plasma pressure pulses in the magnetic flux tube generate MHD slow shocks propagating along the tube. For converging magnetic field lines, such as in a dipole magnetic field, the cross section of the magnetic flux tube decreases enormously with increasing magnetic field strength. In such a case, the propagation of MHD waves along magnetic flux tubes is rather different from that in the case of uniform magnetic fields. In this paper, the propagation of MHD slow shocks is studied numerically using the ideal MHD equations in an approximation suitable for a thin magnetic flux tube with a low plasma beta. The results obtained in the numerical study show that the jumps in the plasma parameters at the MHD slow shock increase greatly while the shock is propagating in the narrowing magnetic flux tube. The results are applied to the case of the interaction between Jupiter and its satellite Io, the latter being considered as a source of plasma pressure pulses.

  6. Mesenteric Air Embolism Following Enteroscopic Small Bowel Tattooing Procedure

    Directory of Open Access Journals (Sweden)

    Natalie Chen

    2012-01-01

    Full Text Available Double balloon enteroscopy (DBE is a revolutionary procedure in which the entire small bowel can be visualized endoscopically. DBE has the advantage of both diagnostic and therapeutic capabilities in the setting of small bowel neoplasms and vascular malformations. We present a unique case of a 76-year-old female who underwent small bowel DBE tattoo marking of a distal small bowel tumor complicated by development of severe abdominal pain postprocedure secondary to bowel air embolism into the mesenteric veins. Mesenteric air can be seen after other endoscopic procedures such as biopsy, mucosal clip placement and polypectomy, or following a colonoscopy. Mesenteric air embolism following small bowel tattooing procedure has not been previously reported in the literature. Mesenteric air when present may be attributed to mesenteric ischemia and can subject the patient to unnecessary surgical intervention if misdiagnosed. Thus, this report holds significance for the radiologist as computed tomography (CT findings of mesenteric air embolism must be evaluated in the context of appropriate clinical history before treatment decisions are made.

  7. Multi-detector CT (MDCT in bowel and mesenteric injury

    Directory of Open Access Journals (Sweden)

    Vajjalla Ravikumar

    2013-04-01

    Full Text Available Objectives: To evaluate multi-detector CT (MDCT findings in bowel and mesenteric injury due to blunt abdominal trauma.Method: Retrospective evaluation of MDCT scan reports of patients admitted in Hamad Medical Corporation, Doha, Qatar with bowel and mesenteric injury during the period of January 2005 to April 2008.Results: MDCT, without using oral contrast, clearly demonstrated various specific and less specific findings of bowel and mesenteric injury.Conclusion: Multi-detector CT is an excellent diagnostic modality in bowel and mesenteric injury. Routine administration of oral contrast agent is not mandatory for initial evaluation of these patients.

  8. Review of Irritable Bowel Syndrome Treatment

    Directory of Open Access Journals (Sweden)

    Ghadir M.R.

    2010-06-01

    Full Text Available Background and Objectives: Irritable bowel syndrome is one of the most common functional gastrointestinal disorders striking 10-20% of the world population. Although most patients do not take medical assistance, this disease enforces significant cost on the patient and health systems and has negative effects on quality of life of the individual. After diagnosis ,treatment of this disease is the next step. Many pathways of treatment has been introduced and the efficacy of each other has been established in one way or another. The first step in the path of treatment is education and confidence of patients that might also be the most important step. Fiber diet, probiotic, anti-cholinergic and anti antispasmodics, laxatives, anti-diarrhea, the drugs affecting serotonin receptors, antidepressants and anti-anxiety, the chloride channel activator and non-drug methods such as cognitive-behavior therapy, hypnotherapy, acupuncture and herbal medicine each of which has been tested on irritable bowel syndrome and efficacy of each one has been indicated in one way or another. This paper tried to outline new treatments available in addition to categorization and discussion of various treatments for irritable bowel syndrome.Keywords: Irritable Bowel Syndrome; Probiotics; Parasmpatholytics; Laxatives.

  9. Bowel Angioedema Associated With Iodinated Contrast Media: Incidence and Predisposing Factors.

    Science.gov (United States)

    Seo, Nieun; Chung, Yong Eun; Lim, Joon Seok; Song, Mi Kyung; Kim, Myeong-Jin; Kim, Ki Whang

    2017-09-01

    Bowel angioedema is an acute adverse reaction to iodinated contrast media (CM) that involves the gastrointestinal tract. We aimed to investigate the incidence and predisposing factors of iodinated CM-associated bowel angioedema during computed tomography (CT) examinations. This study was approved by our institutional review board, and informed consent was waived due to its retrospective design. From July 2013 to July 2015, adult patients with a history of adverse reactions to iodinated CM during CT (group A, n = 427) and patients without adverse reactions matched for age and sex with the propensity-score matching method (group B, n = 427) were studied. Contrast media-associated bowel angioedema was determined when bowel wall thickness increased after contrast enhancement compared with the precontrast scan. Potential predisposing factors including patient demographics, symptoms and time of adverse reactions, and CM-related factors were compared between patients with and without angioedema in group A. In addition, the incidence of bowel angioedema was compared between groups A and B. The incidence of CM-associated bowel angioedema in group A was 3.3% (14/427) in the per-patient analysis and 2.6% (15/578) in the per-examination analysis. The CM-associated bowel angioedema involved the distal duodenum and/or proximal jejunum and showed long-segmental circumferential bowel wall thickening on CT. None of the studied predisposing factors was different between patients with and without bowel angioedema (P > 0.05). The incidence of CM-associated bowel angioedema in group B was 1.9% (8/427) and 1.7% (8/458) for per-patient and per-examination analyses, respectively, and these rates were not significantly different between groups A and B (P = 0.346 and P = 0.370, respectively). The incidence of CM-associated bowel angioedema during CT was 1.7% to 3.3%, and none of the studied predisposing factors was associated with bowel angioedema.

  10. Intestinal barrier integrity and inflammatory bowel disease

    DEFF Research Database (Denmark)

    Holmberg, Fredrik Eric Olof; Pedersen, Jannie; Jørgensen, Peter

    2018-01-01

    Disruption of normal barrier function is a fundamental factor in the pathogenesis of inflammatory bowel disease, which includes increased epithelial cell death, modified mucus configuration, altered expression and distribution of tight junction-proteins, along with a decreased expression of antim......Disruption of normal barrier function is a fundamental factor in the pathogenesis of inflammatory bowel disease, which includes increased epithelial cell death, modified mucus configuration, altered expression and distribution of tight junction-proteins, along with a decreased expression...... of antimicrobial peptides. Inflammatory bowel disease is associated with life-long morbidity for affected patients, and both the incidence and prevalence is increasing globally, resulting in substantial economic strain for society. Mucosal healing and re-establishment of barrier integrity is associated......, novel treatment strategies to accomplish mucosal healing and to re-establish normal barrier integrity in inflammatory bowel disease are warranted, and luminal stem cell-based approaches might have an intriguing potential. Transplantation of in vitro expanded intestinal epithelial stem cells derived...

  11. Radiative capture of slow electrons by tungsten surface

    International Nuclear Information System (INIS)

    Artamonov, O.M.; Belkina, G.M.; Samarin, S.N.; Yakovlev, I.I.

    1987-01-01

    Isochromatic spectra of radiation capture of slow electrons by the surface of mono- and polycrystal tungsten recorded on 322 and 405 nm wave lengths are presented. The effect of oxygen adsorption on isochromates of the (110) face of tungsten monocrystal is investigated. The obtained isochromatic spectra are compared with energy band structure of tungsten. Based on the analysis of the obtained experimental results it is assumed that optical transition to the final state at the energy of 7.3 eV relatively to Fermi level is conditioned by surface states of the tungsten face (110)

  12. Slow Movement/Slow University: Critical Engagements. Introduction to the Thematic Section

    Directory of Open Access Journals (Sweden)

    Maggie O'Neill

    2014-09-01

    Full Text Available This thematic section emerged from two seminars that took place at Durham University in England in November 2013 and March 2014 on the possibilities for thinking through what a change movement towards slow might mean for the University. Slow movements have emerged in relation to a number of topics: Slow food, Citta slow and more recently, slow science. What motivated us in the seminars was to explore how far these movements could help us address the acceleration and intensification of work within our own and other universities, and indeed, what new learning, research, philosophies, practices, structures and governance might emerge. This editorial introduction presents the concept of the "slow university" and introduces our critical engagements with slow. The articles presented here interrogate the potentialities, challenges, problems and pitfalls of the slow university in an era of corporate culture and management rationality. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1403166

  13. Surgical aspects of radiation enteritis of the small bowel

    Energy Technology Data Exchange (ETDEWEB)

    Wobbes, T.; Verschueren, R.C.; Lubbers, E.J.; Jansen, W.; Paping, R.H.

    1984-02-01

    Injury to the small bowel is one of the tragic complications of radiotherapy. We performed a retrospective analysis of patients operated upon for stenosis, perforation, fistulization, and chronic blood loss of the small bowel after radiotherapy for multiple malignant diseases. In the period 1970 to 1982 in the Department of General Surgery of the St. Radboud University Hospital, Nijmegen, and the Department of Surgical Oncology of the State University, Groningen, 27 patients were treated surgically. Twenty patients presented with obstruction. In 17 patients a side-to-side ileotransversostomy was performed; in three the injured bowel was resected. Of the five patients with fistulization, three underwent a bypass procedure; in two cases the affected bowel was resected. In one patient with perforation, a resection was performed, as in a patient with chronic blood loss. Two of the 20 patients (10 per cent) in whom the diseased bowel was bypassed died postoperatively. Of the seven patients whose affected bowel was resected four (57 per cent) died of intra-abdominal sepsis. Management of the patient with chronic radiation enteritis is discussed. We conclude, on the basis of our experience, that in patients with obstruction and fistulization, a bypass procedure of the affected bowel is a safe method of treatment. In case of resection, the anastomosis should be performed during a second operation.

  14. Surgical aspects of radiation enteritis of the small bowel

    International Nuclear Information System (INIS)

    Wobbes, T.; Verschueren, R.C.; Lubbers, E.J.; Jansen, W.; Paping, R.H.

    1984-01-01

    Injury to the small bowel is one of the tragic complications of radiotherapy. We performed a retrospective analysis of patients operated upon for stenosis, perforation, fistulization, and chronic blood loss of the small bowel after radiotherapy for multiple malignant diseases. In the period 1970 to 1982 in the Department of General Surgery of the St. Radboud University Hospital, Nijmegen, and the Department of Surgical Oncology of the State University, Groningen, 27 patients were treated surgically. Twenty patients presented with obstruction. In 17 patients a side-to-side ileotransversostomy was performed; in three the injured bowel was resected. Of the five patients with fistulization, three underwent a bypass procedure; in two cases the affected bowel was resected. In one patient with perforation, a resection was performed, as in a patient with chronic blood loss. Two of the 20 patients (10 per cent) in whom the diseased bowel was bypassed died postoperatively. Of the seven patients whose affected bowel was resected four (57 per cent) died of intra-abdominal sepsis. Management of the patient with chronic radiation enteritis is discussed. We conclude, on the basis of our experience, that in patients with obstruction and fistulization, a bypass procedure of the affected bowel is a safe method of treatment. In case of resection, the anastomosis should be performed during a second operation

  15. Small Bowel Obstruction Caused by Aloe vera Bezoars: A Case Report.

    Science.gov (United States)

    Hong, In Taik; Cha, Jae Myung; Ki, Hye Jin; Kwak, Min Seob; Yoon, Jin Young; Shin, Hyun Phil; Jeoun, Jung Won; Choi, Sung Il

    2017-05-25

    Small bowel obstruction is a clinical condition commonly caused by postoperative adhesion, volvulus, intussusceptions, and hernia. Small bowel obstruction due to bezoars is clinically uncommon, accounting for approximately 2-4% of all obstructions. Computed tomography (CT) is a useful method in diagnosing the cause of small bowel obstruction. However, small bowel obstruction caused by bezoars may not be detected by an abdominal CT examination. Herein, we report a rare case of small bowel obstruction by Aloe vera bezoars, which were undetected by an abdominal CT. Phytobezoars should be included in the differential diagnosis of small bowel obstruction in patients with predisposing factors, such as excessive consumption of high-fiber food and diabetes.

  16. Pharmacological treatment of bowel obstruction in cancer patients.

    LENUS (Irish Health Repository)

    O'Connor, Brenda

    2012-02-01

    INTRODUCTION: Malignant bowel obstruction (MBO) is a common complication of advanced cancer, occurring most frequently in gynaecological and colorectal cancer. Its management remains complex and variable. This is in part due to the lack of evidence-based guidelines for the clinicians involved. Although surgery should be considered the primary treatment, this may not be feasible in patients with a poor performance status or advanced disease. Advances have been made in the medical management of MBO which can lead to a considerable improvement in symptom management and overall quality of life. AREAS COVERED: This review emphasizes the importance of a prompt diagnosis of MBO with early introduction of pharmacological agents to optimize symptom control. The authors summarize the treatment options available for bowel obstruction in those patients for whom surgical intervention is not a feasible option. The authors also explore the complexities involved in the introduction of parenteral hydration and total parenteral nutrition in this group of patients. EXPERT OPINION: It is not always easy to distinguish reversible from irreversible bowel obstruction. Early and aggressive management with the introduction of pharmacological agents including corticosteroids, octreotide and anti-cholinergic agents have the potential to maintain bowel patency, and allow for more rapid recovery of bowel transit. A combination of analgesics, anti-emetics and anti-cholinergics with or without anti-secretory agents can successfully improve symptom control in patients with irreversible bowel obstruction.

  17. CT findings of small bowel metastases from primary lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Wook; Ha, Hyun Kwon; Kim, Ah Young; Kim, Gab Choul; Kim, Tae Kyoung; Kim, Pyo Nyun; Lee, Moon Gyu [Ulsan University College of Medicine, Seoul (Korea, Republic of)

    2002-11-01

    To evaluate the CT findings of small bowel metastases from primary lung cancer. Of the 1468 patients with primary lung cancer between 1990 and 2000, 13 patients who had metastasis to the small intestine were collected. Of these 13 patients, nine who underwent CT scan were included for analysis. The pathologic diagnoses of primary lung cancer in these nine patients were squamous cell carcinoma in six, adenocarcinoma in two, and large cell carcinoma in one. CT scans were analyzed with regard to the site and patterns (intraluminal mass/bowel wall thickening/bowel implants) of metastatic masses, and the presence or absence of complication such as intussusception, obstruction, or perforation of the small bowel. The medical records of the patients were also reviewed retrospectively for evaluation of presenting abdominal symptom and time interval of metastases from initial diagnosis of lung cancer. Metastatic lesions were distributed throughout the small intestine: the duodenum in five, the jejunum in four, the ileum in six, and both jejunum and ileum in one patient. The size of metastatic masses of small bowel ranged from 1.3 cm to 5.0 cm (mean size, 2.6 cm) On CT, the small bowel was involved with intraluminal masses (mean size, 3.4 cm) in eight patients, diffuse wall thickening (mean thickness, 1.6 cm) in five, and bowel implants (mean size, 2.2 cm) in two. Complications occurred in seven patients, including intussusceptions without obstruction in two patients and with obstruction in two, obstruction without intussusceptions in two, and bowel perforation in one. Of 9 patients, 6 had at least one symptom referable to the small bowel including abdominal pain in 4, anemia in 3, vomiting in 1, and jaundice in 1. Lung cancer and small bowel lesions were detected simultaneously in four patients and the time interval of metastases from initial diagnosis of lung cancer ranged from 10 days to 30 months (median interval, 54 days) in patients. CT helps in defining the extent and

  18. CT findings of small bowel metastases from primary lung cancer

    International Nuclear Information System (INIS)

    Kim, Jae Wook; Ha, Hyun Kwon; Kim, Ah Young; Kim, Gab Choul; Kim, Tae Kyoung; Kim, Pyo Nyun; Lee, Moon Gyu

    2002-01-01

    To evaluate the CT findings of small bowel metastases from primary lung cancer. Of the 1468 patients with primary lung cancer between 1990 and 2000, 13 patients who had metastasis to the small intestine were collected. Of these 13 patients, nine who underwent CT scan were included for analysis. The pathologic diagnoses of primary lung cancer in these nine patients were squamous cell carcinoma in six, adenocarcinoma in two, and large cell carcinoma in one. CT scans were analyzed with regard to the site and patterns (intraluminal mass/bowel wall thickening/bowel implants) of metastatic masses, and the presence or absence of complication such as intussusception, obstruction, or perforation of the small bowel. The medical records of the patients were also reviewed retrospectively for evaluation of presenting abdominal symptom and time interval of metastases from initial diagnosis of lung cancer. Metastatic lesions were distributed throughout the small intestine: the duodenum in five, the jejunum in four, the ileum in six, and both jejunum and ileum in one patient. The size of metastatic masses of small bowel ranged from 1.3 cm to 5.0 cm (mean size, 2.6 cm) On CT, the small bowel was involved with intraluminal masses (mean size, 3.4 cm) in eight patients, diffuse wall thickening (mean thickness, 1.6 cm) in five, and bowel implants (mean size, 2.2 cm) in two. Complications occurred in seven patients, including intussusceptions without obstruction in two patients and with obstruction in two, obstruction without intussusceptions in two, and bowel perforation in one. Of 9 patients, 6 had at least one symptom referable to the small bowel including abdominal pain in 4, anemia in 3, vomiting in 1, and jaundice in 1. Lung cancer and small bowel lesions were detected simultaneously in four patients and the time interval of metastases from initial diagnosis of lung cancer ranged from 10 days to 30 months (median interval, 54 days) in patients. CT helps in defining the extent and

  19. Physics of ultrasonic wave propagation in bone and heart characterized using Bayesian parameter estimation

    Science.gov (United States)

    Anderson, Christian Carl

    This Dissertation explores the physics underlying the propagation of ultrasonic waves in bone and in heart tissue through the use of Bayesian probability theory. Quantitative ultrasound is a noninvasive modality used for clinical detection, characterization, and evaluation of bone quality and cardiovascular disease. Approaches that extend the state of knowledge of the physics underpinning the interaction of ultrasound with inherently inhomogeneous and isotropic tissue have the potential to enhance its clinical utility. Simulations of fast and slow compressional wave propagation in cancellous bone were carried out to demonstrate the plausibility of a proposed explanation for the widely reported anomalous negative dispersion in cancellous bone. The results showed that negative dispersion could arise from analysis that proceeded under the assumption that the data consist of only a single ultrasonic wave, when in fact two overlapping and interfering waves are present. The confounding effect of overlapping fast and slow waves was addressed by applying Bayesian parameter estimation to simulated data, to experimental data acquired on bone-mimicking phantoms, and to data acquired in vitro on cancellous bone. The Bayesian approach successfully estimated the properties of the individual fast and slow waves even when they strongly overlapped in the acquired data. The Bayesian parameter estimation technique was further applied to an investigation of the anisotropy of ultrasonic properties in cancellous bone. The degree to which fast and slow waves overlap is partially determined by the angle of insonation of ultrasound relative to the predominant direction of trabecular orientation. In the past, studies of anisotropy have been limited by interference between fast and slow waves over a portion of the range of insonation angles. Bayesian analysis estimated attenuation, velocity, and amplitude parameters over the entire range of insonation angles, allowing a more complete

  20. Oblique Modulation of Ion-Acoustic Waves in a Warm Plasma

    International Nuclear Information System (INIS)

    Xue Jukui; Tang Rongan

    2003-01-01

    The stability of oblique modulation of ion-acoustic waves in an unmagnetized warm plasma is studied. A nonlinear Schroedinger equation governing the slow modulation of the wave amplitude is derived. The effect of temperature on the oblique modulational instability of the ion-acoustic wave is investigated. It is found that the ion temperature significantly changes the domain of the modulational instability in the k-θ plane

  1. Acute bowel ischemia: CT findings

    International Nuclear Information System (INIS)

    Angelelli, Giuseppe; Scardapane, Arnaldo; Memeo, Maurizio; Stabile Ianora, Amato Antonio; Rotondo, Antonio

    2004-01-01

    Acute bowel ischemia represents one of the most dramatic abdominal emergencies and, despite the fact it is more and more frequently observed in clinical practice, its mortality rate remains very high. In recent years Computed Tomography (CT) has proved to be a valid diagnostic tool in the evaluation of patients with acute abdominal syndrome and in the visualization of early signs of bowel ischemia. This paper reviews the aetiological and pathophysiological aspects as well as a broad spectrum of CT findings of this clinical condition

  2. [Bowel-associated dermatosis-arthritis syndrome during ulcerative colitis: A rare extra-intestinal sign of inflammatory bowel disease].

    Science.gov (United States)

    Aounallah, A; Zerriaa, S; Ksiaa, M; Jaziri, H; Boussofara, L; Ghariani, N; Mokni, S; Saidi, W; Sriha, B; Belajouza, C; Denguezli, M; Nouira, R

    2016-05-01

    Bowel-associated dermatosis-arthritis syndrome (BADAS) is characterized by combined pustular skin eruption and arthralgia. It may be associated with inflammatory bowel disease or bowel bypass surgery. We report a case of BADAS in a patient with ulcerative colitis. A 39-year-old woman was being treated for a severe flare-up of ulcerative colitis present over the preceding 2 months and treated with prednisone, azathioprine and cyclosporine. She was also presenting a cutaneous eruption and arthralgia that had begun three days earlier. Dermatological examination revealed profuse vesicular and pustular lesions. Biopsy specimens showed mature neutrophilic infiltrate within the dermis. A diagnosis of BADAS was made and the same treatment was maintained. Systemic symptoms were resolved but the vesicular lesions were superseded by hypertrophic scars. Bowel-associated dermatosis-arthritis syndrome consists of a vesiculopustular eruption associated with arthralgia and/or arthritis and fever, as was the case in our patient. The histological picture is characterized by abundant neutrophilic infiltrate in the superficial dermis. The clinical and histological features and the course of BADAS allow this entity to be classified within the spectrum of neutrophilic dermatoses. Treatment chiefly involves systemic corticosteroids. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  3. Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE)

    DEFF Research Database (Denmark)

    Peyrin-Biroulet, L; Sandborn, W; Sands, B E

    2015-01-01

    OBJECTIVES: The Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) program was initiated by the International Organization for the Study of Inflammatory Bowel Diseases (IOIBD). It examined potential treatment targets for inflammatory bowel disease (IBD) to be used for a "treat-t...... target. CONCLUSIONS: Evidence- and consensus-based recommendations for selecting the goals for treat-to-target strategies in patients with IBD are made available. Prospective studies are needed to determine how these targets will change disease course and patients' quality of life....

  4. Differentiation between active and chronic Crohn's disease using MRI small-bowel motility examinations — Initial experience

    International Nuclear Information System (INIS)

    Bickelhaupt, S.; Froehlich, J.M.; Cattin, R.; Patuto, N.; Tutuian, R.; Wentz, K.U.; Culmann, J.L.; Raible, S.; Bouquet, H.; Bill, U.; Patak, M.A.

    2013-01-01

    active Crohn's disease alters small-bowel motility in distant, non-affected segments. The motility patterns revealed reduced contraction-wave frequencies, amplitudes, and decreased luminal occlusion rates. Thus evaluation of these characteristics potentially helps to differentiate between chronic and active Crohn's disease

  5. Irritable bowel syndrome, the microbiota and the gut-brain axis

    DEFF Research Database (Denmark)

    Raskov, Hans; Burcharth, Jakob; Pommergaard, Hans-Christian

    2016-01-01

    Irritable bowel syndrome is a common functional gastrointestinal disorder and it is now evident that irritable bowel syndrome is a multi-factorial complex of changes in microbiota and immunology. The bidirectional neurohumoral integrated communication between the microbiota and the autonomous...... nervous system is called the gut-brain-axis, which integrates brain and GI functions, such as gut motility, appetite and weight. The gut-brain-axis has a central function in the perpetuation of irritable bowel syndrome and the microbiota plays a critical role. The purpose of this article is to review...... recent research concerning the epidemiology of irritable bowel syndrome, influence of microbiota, probiota, gut-brain-axis, and possible treatment modalities on irritable bowel syndrome....

  6. Surgical management of irradiation-induced small bowel damage

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.T.; Seski, J.C.; Copeland, L.J.; Gershenson, D.M.; Edwards, C.L.; Herson, J.

    1985-04-01

    Seventy-seven patients, presenting with radiation small bowel injuries at the University of Texas M. D. Anderson Hospital and Tumor Institute at Houston between 1962 and 1978, were analyzed retrospectively. The patients were divided into two categories: bowel bypass without resection, and resection of irradiated bowel. Each group was then analyzed for its short- and long-term complications. Ileocolectomy with end-to-end anastomosis was the surgical procedure of choice in those people undergoing resection. There was no difference in short-term complications noted between the two groups. The long-term complications of fistula formation and continued small bowel necrosis could be prevented by resection, as a primary procedure. The surgical details of ileocolectomy with end-to-end anastomosis are presented, along with an analysis of the complications encountered in both groups.

  7. Surgical management of irradiation-induced small bowel damage

    International Nuclear Information System (INIS)

    Smith, S.T.; Seski, J.C.; Copeland, L.J.; Gershenson, D.M.; Edwards, C.L.; Herson, J.

    1985-01-01

    Seventy-seven patients, presenting with radiation small bowel injuries at the University of Texas M. D. Anderson Hospital and Tumor Institute at Houston between 1962 and 1978, were analyzed retrospectively. The patients were divided into two categories: bowel bypass without resection, and resection of irradiated bowel. Each group was then analyzed for its short- and long-term complications. Ileocolectomy with end-to-end anastomosis was the surgical procedure of choice in those people undergoing resection. There was no difference in short-term complications noted between the two groups. The long-term complications of fistula formation and continued small bowel necrosis could be prevented by resection, as a primary procedure. The surgical details of ileocolectomy with end-to-end anastomosis are presented, along with an analysis of the complications encountered in both groups

  8. Small bowel volvulus with jejunal diverticulum: Primary or secondary?

    Science.gov (United States)

    Shen, Xiao-Fei; Guan, Wen-Xian; Cao, Ke; Wang, Hao; Du, Jun-Feng

    2015-09-28

    Small bowel volvulus, which is torsion of the small bowel and its mesentery, is a medical emergency, and is categorized as primary or secondary type. Primary type often occurs without any apparent intrinsic anatomical anomalies, while the secondary type is common clinically and could be caused by numerous factors including postoperative adhesions, intestinal diverticulum, and/or tumors. Here, we report a rare case of a 60-year-old man diagnosed with small bowel volvulus using multidetector computed tomography (MDCT) angiography. Further discovery by laparotomy showed one jejunal diverticulum, longer corresponding mesentery with a narrower insertion, and a lack of mesenteric fat. This case report includes several etiological factors of small bowel volvulus, and we discuss the possible cause of small bowel volvulus in this patient. We also highlight the importance of MDCT angiography in the diagnosis of volvulus and share our experience in treating this disease.

  9. Retrieval of recent autobiographical memories is associated with slow-wave sleep in early AD.

    Directory of Open Access Journals (Sweden)

    Géraldine eRAUCHS

    2013-09-01

    Full Text Available Autobiographical memory is commonly impaired in Alzheimer’s disease (AD. However, little is known about the very recent past which is though highly important in daily life adaptation. In addition, the impact of sleep disturbances, also frequently reported in AD, on the consolidation and retrieval of autobiographical memories remains to be assessed. Using an adaptation of the TEMPau task, we investigated the neural substrates of autobiographical memory for recent events and the potential relationship with sleep in 14 patients with mild AD. On day 1, autobiographical memory was explored across 3 periods: remote (18-30 years, the last two years and the last month. After testing, sleep was recorded using polysomnography. The next day, AD patients benefited a resting state 18FDG-PET scan and a second exploration of autobiographical memory, focusing on the very recent past (today and yesterday. Total recall and episodic recall scores were obtained. In addition, for all events recalled, Remember responses justified by specific factual, spatial and temporal details were measured using the Remember/Know paradigm. Retrieval of autobiographical memories was impaired in AD, but recall of young adulthood and very recent events was relatively better compared to the two intermediate periods. Recall of recent events (experienced the day and the day preceding the assessment was correlated with brain glucose consumption in the precuneus and retrosplenial cortex, the calcarine region, the angular gyrus and lateral temporal areas. AD patients also provided more Justified Remember responses for events experienced the previous day than for those experienced the day of the assessment. Moreover, Justified Remember responses obtained for events experienced before sleep were positively correlated with the amount of slow-wave sleep. These data provide the first evidence of an association between the ability to retrieve recent autobiographical memories and sleep in mild

  10. Observation and excitation of magnetohydrodynamic waves in numerical models of Earth's core

    Science.gov (United States)

    Teed, R.; Hori, K.; Tobias, S.; Jones, C. A.

    2017-12-01

    Several types of magnetohydrodynamic waves are theorised to operate in Earth's outer core but their detection is limited by the inability to probe the fluid core directly. Secular variation data and periodic changes in Earth's length-of-day provide evidence for the possible existence of waves. Numerical simulations of core dynamics enable us to search directly for waves and determine their properties. With this information it is possible to consider whether they can be the origin of features observed in observational data. We focus on two types of wave identified in our numerical experiments: i) torsional waves and ii) slow magnetic Rossby waves. Our models display periodic, Earth-like torsional waves that travel outwards from the tangent cylinder circumscribing the inner core. We discuss the properties of these waves and their similarites to observational data. Excitation is via a matching of the Alfvén frequency with that of small modes of convection focused at the tangent cylinder. The slow magnetic Rossby waves observed in our simulations show that these waves may account for some geomagnetic westward drifts observed at mid-latitudes. We present analysis showing excitation of waves by the convective instability and we discuss how the detection of these waves could also provide an estimate of the strength of the toroidal component of the magnetic field within the planetary fluid core.

  11. Pathophysiology of the nodular and micronodular small bowel fold

    International Nuclear Information System (INIS)

    Olmstead, W.W.; Ros, P.R.; Moser, R.P.; Shekitka, K.M.; Lichtenstein, J.E.; Buck, J.L.

    1987-01-01

    The normal small bowel fold is easily seen on conventional studies of the small intestine, but visualization of the small bowel villus is just at the resolution of current roentgenographic technique. When the villi are enlarged, they can be seen radiographically as an irregularity or micronodularity of the small bowel fold. The anatomy of the fold and the pathophysiology of diseases producing fold nodularity (tumor, inflammatory disease, NLH, mastocytosis) and micronodularity (lymphangiectasia, Waldenstrom macroglobulinemia, Whipple disease) are presented, with an emphasis on radiologic-pathologic correlation. The radiologist should suggest certain diseases or conditions based on the roentgenographic characteristics of the closely analyzed small bowel fold

  12. The role of fecal calprotectin in investigating inflammatory bowel diseases

    Directory of Open Access Journals (Sweden)

    Mustafa Erbayrak

    2009-05-01

    Full Text Available INTRODUCTION: Invasive and non-invasive tests can be used to evaluate the activity of inflammatory bowel diseases. OBJECTIVE: The aim of the present study was to investigate the role of fecal calprotectin in evaluating inflammatory bowel disease activity and the correlation of fecal calprotectin with the erythrocyte sedimentation rate and C reactive protein values in inflammatory bowel disease. METHOD: Sixty-five patients affected with inflammatory bowel disease were enrolled. Twenty outpatients diagnosed with inflammatory bowel disease comprised the control group. RESULTS: In the present study, all patients in the control group had an fecal calprotectin value lower than the cut-off point (50 mg/kg. CONCLUSION: In conclusion, fecal calprotectin was found to be strongly associated with colorectal inflammation indicating organic disease. Fecal calprotectin is a simple and non-invasive method for assessing excretion of macrophages into the gut lumen. Fecal calprotectin values can be used to evaluate the response to treatment, to screen asymptomatic patients, and to predict inflammatory bowel disease relapses.

  13. Detection of Nocturnal Slow Wave Sleep Based on Cardiorespiratory Activity in Healthy Adults.

    Science.gov (United States)

    Long, Xi; Fonseca, Pedro; Aarts, Ronald M; Haakma, Reinder; Rolink, Jerome; Leonhardt, Steffen

    2017-01-01

    Human slow wave sleep (SWS) during bedtime is paramount for energy conservation and memory consolidation. This study aims at automatically detecting SWS from nocturnal sleep using cardiorespiratory signals that can be acquired with unobtrusive sensors in a home-based scenario. From the signals, time-dependent features are extracted for continuous 30-s epochs. To reduce the measuring noise, body motion artifacts, and/or within-subject variability in physiology conveyed by the features, and thus, enhance the detection performance, we propose to smooth the features over each night using a spline fitting method. In addition, it was found that the changes in cardiorespiratory activity precede the transitions between SWS and the other sleep stages (non-SWS). To this matter, a novel scheme is proposed that performs the SWS detection for each epoch using the feature values prior to that epoch. Experiments were conducted with a large dataset of 325 overnight polysomnography (PSG) recordings using a linear discriminant classifier and tenfold cross validation. Features were selected with a correlation-based method. Results show that the performance in classifying SWS and non-SWS can be significantly improved when smoothing the features and using the preceding feature values of 5-min earlier. We achieved a Cohen's Kappa coefficient of 0.57 (at an accuracy of 88.8%) using only six selected features for 257 recordings with a minimum of 30-min overnight SWS that were considered representative of their habitual sleeping pattern at home. These features included the standard deviation, low-frequency spectral power, and detrended fluctuation of heartbeat intervals as well as the variations of respiratory frequency and upper and lower respiratory envelopes. A marked drop in Kappa to 0.21 was observed for the other nights with SWS time of less than 30 min, which were found to more likely occur in elderly. This will be the future challenge in cardiorespiratory-based SWS detection.

  14. NUMERICAL EXPERIMENTS OF WAVE-LIKE PHENOMENA CAUSED BY THE DISRUPTION OF AN UNSTABLE MAGNETIC CONFIGURATION

    International Nuclear Information System (INIS)

    Wang Hongjuan; Shen Chengcai; Lin Jun

    2009-01-01

    The origin of the Moreton wave observed in the chromosphere and the EIT wave observed in the corona during the eruption remains an active research subject. We investigate numerically in this work the evolutionary features of the magnetic configuration that includes a current-carrying flux rope, which is used to model the filament, after the loss of equilibrium in the system takes place in a catastrophic fashion. Rapid motions of the flux rope following the catastrophe invoke the velocity vortices behind the rope, and may also invoke slow- and fast-mode shocks in front of the rope. The velocity vortices at each side of the flux rope propagate roughly horizontally away from the area where they are produced, and both shocks expand toward the flank of the flux rope. The fast shock may eventually reach the bottom boundary and produce two echoes moving back into the corona, but the slow one and the vortices totally decay somewhere in the lower corona before arriving of the bottom boundary. The interaction of the fast shock with the boundary leads to disturbance that accounts for the Moreton wave observed in Hα, and the disturbance in the corona caused by the slow shock and the velocity vortices should account for the EIT wave whose speed is about 40% that of the Moreton wave. The implication of these results to the observed correlation of the type II radio burst to the fast- and the slow-mode shocks and that of EIT waves to coronal mass ejections and flares has also been discussed.

  15. Predicting inadequate bowel preparation for colonoscopy in participants receiving split-dose bowel preparation: development and validation of a prediction score

    NARCIS (Netherlands)

    Dik, V.K.; Moons, L.M.; Huyuk, M.; Schaar, P. van der; Cappel, W.H. de Vos Tot Nede; Borg, P.C. ter; Meijssen, M.A.; Ouwendijk, R.J.; Fevre, D.M. Le; Stouten, M.; Galien, O. van der; Hiemstra, T.J.; Monkelbaan, J.F.; Oijen, M.G. van; Siersema, P.D.

    2015-01-01

    BACKGROUND: Adequate bowel preparation is important for optimal colonoscopy. It is important to identify patients at risk for inadequate bowel preparation because this allows taking precautions in this specific group. OBJECTIVE: To develop a prediction score to identify patients at risk for

  16. Predicting inadequate bowel preparation for colonoscopy in participants receiving split-dose bowel preparation : Development and validation of a prediction score

    NARCIS (Netherlands)

    Dik, Vincent K.; Moons, Leon M G; Hüyük, Melek; Van Der Schaar, Peter; De Vos Tot Nederveen Cappel, Wouter H.; Ter Borg, Pieter C J; Meijssen, Maarten A C; Ouwendijk, Rob J T H; Le Fèvre, Doris M.; Stouten, Merijn; Van Der Galiën, Onno; Hiemstra, Theo J.; Monkelbaan, Jan F.; van Oijen, Martijn G. H.; Siersema, Peter D.; Tang, Thjon J.; Ter Borg, Frank; Kuipers, Ernst J.

    2015-01-01

    Background: Adequate bowel preparation is important for optimal colonoscopy. It is important to identify patients at risk for inadequate bowel preparation because this allows taking precautions in this specific group. Objective: To develop a prediction score to identify patients at risk for

  17. Small bowel resection

    Science.gov (United States)

    ... Ileostomy and your diet Ileostomy - caring for your stoma Ileostomy - changing your pouch Ileostomy - discharge Ileostomy - what to ask your doctor Low-fiber diet Preventing falls Small bowel resection - discharge Surgical wound care - open Types of ileostomy Ulcerative colitis - discharge When ...

  18. Dose-volume correlation in radiation-related late small-bowel complication

    International Nuclear Information System (INIS)

    Letschert, J.G.J.; Lebesque, J.V.; Boer, R.W. de; hart, A.A.M.; Barteling, H.

    1990-01-01

    The effects of the volume of irradiated small bowel on late small-bowel tolerance was studied, taking into account the equivalent total dose ant type of pre-irradiation surgical procedure. A method was developed to estimate small-bowel volumes in the high-bowel volumes were measured for three-field and AP-PA pelvic treatments (165 cm 3 and 400 cm 3 , respectively), extended AP-PA treatment of para-aortic and iliac nodes (1000 cm 3 ). In a retrospective study of 111 patientst irradiated after surgery for rectal or recto-sigmoid cancer to a dose of 45-50 Gy in 5 weeks, extended AP-PA pelvic treatment (n = 27) resulted in a high incidence of severe small-bowel complications (37%), whereas for limited (three-field) pelvic treatment (n = 84) the complication rate was 6%. These complication data together with data from the literature on postoperative radiation-related small-bowel complications were analysed using the maximum likelihood method to fit the data to the logistic form of the dose-response relation, taking the volume effect into account by a power law. The analysis indicated that the incidence of radiation-related small-bowel compllications was higher after rectal surgery than after other types of surgery, which might be explained by the development of more adhesions. For both types of surgery a volume exponent of the power-law of 0.26 ± 0.05 was established. This means that if the small-bowel volume is increased by a factor of 2, the total dose has to be reduced by 17% for the same incidence of small-bowel complications. (author). 45 refs.; 6 figs.; 4 tabs

  19. Development of a 2 MW relativistic backward wave oscillator

    Indian Academy of Sciences (India)

    In this paper, a high power relativistic backward wave oscillator (BWO) experiment is reported. A 230 keV, 2 kA, 150 ns relativistic electron beam is generated using a Marx generator. The beam is then injected into a hollow rippled wall metallic cylindrical tube that forms a slow wave structure. The beam is guided using an ...

  20. Inflammatory bowel disease and irritable bowel syndrome: similarities and differences.

    Science.gov (United States)

    Barbara, Giovanni; Cremon, Cesare; Stanghellini, Vincenzo

    2014-07-01

    Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) are classically viewed as dichotomous conditions. The former is perceived as a typical organic disease, and the latter is regarded as a disorder of gut function driven by mood. Recent research identified some shared contributing factors, which will be discussed here. Mounting evidence shows the importance in both IBD and IBS of genetic, microbiological, epithelial, and immunological factors. In some instances, these factors overlap in the two conditions as shown by: involvement of brain-gut axis dysfunction in IBD, implication of TNFSF gene in Crohn's disease and IBS, evidence of abnormal microbiota and its impact on host functions, identification of low-grade inflammation in subsets of IBS patients, and development of IBS symptoms in patients with IBD in remission. IBD and IBS remain separate conditions although there are some overlapping mechanisms. Both research and clinical management would benefit from considering a functional approach for certain manifestations of IBD and accepting an organic view in subsets of IBS patients.

  1. Bowel preparations for colonoscopy: an RCT.

    Science.gov (United States)

    Di Nardo, Giovanni; Aloi, Marina; Cucchiara, Salvatore; Spada, Cristiano; Hassan, Cesare; Civitelli, Fortunata; Nuti, Federica; Ziparo, Chiara; Pession, Andrea; Lima, Mario; La Torre, Giuseppe; Oliva, Salvatore

    2014-08-01

    The ideal preparation regimen for pediatric colonoscopy remains elusive, and available preparations continue to represent a challenge for children. The aim of this study was to compare the efficacy, safety, tolerability, and acceptance of 4 methods of bowel cleansing before colonoscopy in children. This randomized, investigator-blinded, noninferiority trial enrolled all children aged 2 to 18 years undergoing elective colonoscopy in a referral center for pediatric gastroenterology. Patients were randomly assigned to receive polyethylene glycol (PEG) 4000 with simethicon (PEG-ELS group) or PEG-4000 with citrates and simethicone plus bisacodyl (PEG-CS+Bisacodyl group), or PEG 3350 with ascorbic acid (PEG-Asc group), or sodium picosulfate plus magnesium oxide and citric acid (NaPico+MgCit group). Bowel cleansing was evaluated according to the Boston Bowel Preparation Scale. The primary end point was overall colon cleansing. Tolerability, acceptability, and compliance were also evaluated. Two hundred ninety-nine patients were randomly allocated to the 4 groups. In the per-protocol analysis, PEG-CS+Bisacodyl, PEG-Asc, and NaPico+MgCit were noninferior to PEG-ELS in bowel-cleansing efficacy of both the whole colon (P = .910) and colonic segments. No serious adverse events occurred in any group. Rates of tolerability, acceptability, and compliance were significantly higher in the NaPico+MgCit group. Low-volume PEG preparations (PEG-CS+Bisacodyl, PEG-Asc) and NaPico+MgCit are noninferior to PEG-ELS in children, representing an attractive alternative to high-volume regimens in clinical practice. Because of the higher tolerability and acceptability profile, NaPico+MgCit would appear as the most suitable regimen for bowel preparation in children. Copyright © 2014 by the American Academy of Pediatrics.

  2. What People with Inflammatory Bowel Disease Need to Know about Osteoporosis

    Science.gov (United States)

    ... Bowel Disease Need to Know About Osteoporosis What People With Inflammatory Bowel Disease Need to Know About ... in all or part of the large intestine. People with inflammatory bowel disease (IBD) often have diarrhea, ...

  3. Bowel wall visualisation at CT colonography

    International Nuclear Information System (INIS)

    Svensson, M.H.; Hellstroem, M.; Svensson, E.

    2002-01-01

    Purpose: To evaluate the quality of bowel wall visualisation at CT colonography and the impact of examination in the supine and prone positions. Material and Methods: After bowel preparation, 111 patients underwent CT colonography. Air distension, degree of fluid redistribution with change in body position (supine and prone), influence of residual stool on bowel wall assessability, and quality of overall colon visualisation were evaluated using scales. Results: Thirty of 110 patients (27%) had complete overall visualisation of the colon wall and 52 (47%) had subtotal visualisation of a limited part of the colon. The entire colon was more often air-filled in the prone position (46%) than in the supine position (18%). Joint review of supine and prone data showed that for all colon segments, except the sigmoid (86%), 95% of the patients had complete air filling. All patients had residual fluid. In 75% to 99%, depending on segment, fluid did not interfere with the bowel wall visualisation in the combined evaluation of supine and prone data sets. Thirty-one patients had residual stool with potential negative influence on polyp detection. Conclusions: The colon wall was completely, or almost completely, visualised in 75% of the patients, and examination in the supine and prone positions was necessary for complete visualisation

  4. Bowel disease after radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Schofield, P.F.; Holden, D.; Carr, N.D. (Christie Hospital and Holt Radium Inst., Manchester (UK))

    1983-06-01

    The clinical presentation, operative findings and outcome in 40 patients who required surgery for bowel disease after radiotherapy are presented. The type of presentation varied according to the time after radiotherapy. In the first month, many patients had a proctitis but none required surgery. Five patients were operated on within one month, 2 for radiation-induced acute ileitis and 3 for exacerbations of pre-existing disease (diverticular disease 2, ulcerative colitis 1). The commonest time of presentation was between 3 and 18 months after radiotherapy, when 20 patients needed surgery for bowel disease caused by radiation-induced local ischaemia. Twelve of these patients had chronic perforation, 6 had severe rectal bleeding and 2 had painful anorectal ulceration. Fifteen patients presented between 2 and 24 years after radiotherapy, usually with incomplete intestinal obstruction due to a fibrous stricture, but 2 patients had rectal carcinoma. Wide resection of the involved bowel was the principal method of treatment but any anastomosis was protected by a proximal defunctioning stoma. There was no operative mortality but 10 patients have died subsequently. The danger of dismissing these patients as having incurable malignancy is stressed because, although the condition is infrequent, it is usually amenable to adequate surgery.

  5. Solar radiation is inversely associated with inflammatory bowel disease admissions.

    Science.gov (United States)

    Jaime, Francisca; Riutort, Maria C; Alvarez-Lobos, Manuel; Hoyos-Bachiloglu, Rodrigo; Camargo, Carlos A; Borzutzky, Arturo

    To explore the associations between latitude and solar radiation with inflammatory bowel disease admission rates in Chile, the country with the largest variation in solar radiation in the world. This is an ecological study, which included data on all hospital-admitted population for inflammatory bowel disease between 2001 and 2012, according to different latitudes and solar radiation exposures in Chile. The data were acquired from the national hospital discharge database from the Department of Health Statistics and Information of the Chilean Ministry of Health. Between 2001 and 2012 there were 12,869 admissions due to inflammatory bowel disease (69% ulcerative colitis, 31% Crohn's disease). Median age was 36 years (IQR: 25-51); 57% were female. The national inflammatory bowel disease admission rate was 6.52 (95% CI: 6.40-6.63) per 100,000 inhabitants with increasing rates over the 12-year period. In terms of latitude, the highest admission rates for pediatric ulcerative colitis and Crohn's disease, as well as adult ulcerative colitis, were observed in the southernmost region with lowest annual solar radiation. Linear regression analysis showed that regional solar radiation was inversely associated with inflammatory bowel disease admissions in Chile (β: -.44, p = .03). Regional solar radiation was inversely associated with inflammatory bowel disease admission rates in Chile; inflammatory bowel disease admissions were highest in the southernmost region with lowest solar radiation. Our results support the potential role of vitamin D deficiency on inflammatory bowel disease flares.

  6. Consensus guidelines for the use of bowel preparation prior to colonic diagnostic procedures: colonoscopy and small bowel video capsule endoscopy

    NARCIS (Netherlands)

    Mathus-Vliegen, Elisabeth; Pellisé, Maria; Heresbach, Denis; Fischbach, Wolfgang; Dixon, Tricia; Belsey, Jonathan; Parente, Fabrizio; Rio-Tinto, Ricardo; Brown, Alistair; Toth, Ervin; Crosta, Cristiano; Layer, Peter; Epstein, Owen; Boustiere, Christian

    2013-01-01

    Adequate bowel preparation prior to colonic diagnostic procedures is essential to ensure adequate visualisation. This consensus aims to provide guidance as to the appropriate use of bowel preparation for a range of defined clinical circumstances. A consensus group from across Europe was convened and

  7. Relative merits of travelling-wave and resonant operation of linac

    International Nuclear Information System (INIS)

    Shoffstall, D.R.; Gallagher, W.J.

    1985-01-01

    Discussion of the relative merits of so-called standing wave vis-a-vis travelling wave operation of linear accelerator waveguides is complicated by various considerations. In the first instance, standing wave should be distinguished from resonant operation. Standing wave operation is exactly the same as travelling wave, excepting that the waveguide is terminated by a total reflection of power instead of a matched load. In resonant operation a length of slow wave structure is terminated, theoretically at reflection planes of symmetry; the discrete modes of resonance consist of two oppositely directed travelling wave ensembles, one of which will provide a space harmonic of an intended phase velocity

  8. An 8-year old boy with continuous spikes and waves during slow sleep presenting with positive onconeuronal antibodies.

    Science.gov (United States)

    Hu, Lin-Yan; Shi, Xiu-Yu; Feng, Chen; Wang, Jian-Wen; Yang, Guan; Lammers, Stephen H T; Yang, Xiao Fan; Ebrahimi-Fakhari, Darius; Zou, Li-Ping

    2015-03-01

    To determine the etiology of epilepsy with continuous spikes and waves during slow sleep (CSWS)/electrical status epilepticus during sleep (ESES) in an 8-year old boy with a history of neuroblastoma and opsoclonus-myoclonus. A combination of clinical characterization and follow-up, video EEG and laboratory investigations. We report the case of an 8-year old boy with a history of neuroblastoma and opsoclonus-myoclonus, who presented with intellectual disability, pharmacotherapy-resistant epilepsy and CSWS/ESES. Although the patient's neuroblastoma had been successfully treated 8 years prior to presentation and an extensive workup did not show a tumor reoccurrence, testing for onconeuronal antibodies was positive for anti-Ma2 and anti-CV2/CRMP5 antibodies. High-dose intravenous methylprednisolone and a taper of oral methylprednisolone were given, leading to a significant clinical improvement. During the taper the patient's condition and EEG manifestations deteriorated again necessitating another cycle of steroid therapy, which lead to a stable improvement. During a 6-month follow-up no CSWS/ESES was seen on EEG and anti-Ma2 and anti-CV2/CRMP5 antibodies remained undetectable. This case suggests that onconeuronal antibodies may be involved in the pathogenesis of CSWS/ESES. Copyright © 2015 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  9. Early bowel complications following radiotherapy of uterine cervix carcinoma

    International Nuclear Information System (INIS)

    Kim, Won Dong

    1999-01-01

    This study evaluated early bowel complications in cervix cancer patients, following external radiotherapy (ERT) and high dose rate intracavitary radiation (HDR ICR). Factors affecting the risk of developing early bowel complications and its incidence are analyzed and discussed. The study is the retrospective review of 66 patients who received radiotherapy at Chungbuk National University Hospital from April 1994 to December 1998. The patients underwent 41.4 or 50.4 Gy ERT according to FIGO stage and tumor size, then A point dose was boosted to 71.4 or 74.4 Gy using a remotely controlled after loading Buchler HDR ICR. The EORTC/RTOG morbidity criteria were used to grade early bowel complications, which are valid from day 1, the commencement of therapy, through day 90. The actuarial incidence, severity of complications were investigated and clinical pretreatment factors relevant to complications were found through univariate (Wilcoxon) and multivariate (Cox proportional hazard model) analysis. Of the 66 patients, 30 patients (46%) developed early bowel complications; 25 patients (38%) with grade 1 or 2, 4 patients (6%) with grade 3 and 1 patient (2%) with grade 4. The complications usually began to occur 3 weeks after the commencement of radiotherapy. The actuarial incidence of early bowel complications was 41% at 10 weeks. The early bowel complications were associated significantly with an old age and a history of previous abdomino-pelvic surgery. All three patients who had a protracted overall treatment time (about 2 weeks) due to severe bowel complication, suffered from pelvic recurrences. Forty six percent of patients experienced early bowel complications, most of which were grade 1 or 2 and relieved spontaneously or by medication. The patients with an old age or a previous surgery have a high probability of early complications and they may be less compliant with planned radiotherapy. So more careful precaution is necessary for these patients

  10. Visceral hypersensitivity in Irritable Bowel Syndrome:pathophysiological mechanisms

    NARCIS (Netherlands)

    Kerckhoffs, A.P.M.

    2009-01-01

    Irritable Bowel Syndrome (IBS) is a functional bowel disease characterized by abdominal pain or discomfort associated with a disordered defecation. No unique pathophysiological mechanism has been identified. It is most likely a multifactorial disease involving alterations in intestinal microbiota

  11. Nonlinear extraordinary wave in dense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Krasovitskiy, V. B., E-mail: krasovit@mail.ru [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation); Turikov, V. A. [Russian University of Peoples’ Friendship (Russian Federation)

    2013-10-15

    Conditions for the propagation of a slow extraordinary wave in dense magnetized plasma are found. A solution to the set of relativistic hydrodynamic equations and Maxwell’s equations under the plasma resonance conditions, when the phase velocity of the nonlinear wave is equal to the speed of light, is obtained. The deviation of the wave frequency from the resonance frequency is accompanied by nonlinear longitudinal-transverse oscillations. It is shown that, in this case, the solution to the set of self-consistent equations obtained by averaging the initial equations over the period of high-frequency oscillations has the form of an envelope soliton. The possibility of excitation of a nonlinear wave in plasma by an external electromagnetic pulse is confirmed by numerical simulations.

  12. Nonlinear two-fluid hydromagnetic waves in the solar wind: Rotational discontinuity, soliton, and finite-extent Alfven wave train solutions

    International Nuclear Information System (INIS)

    Lyu, L.H.; Kan, J.R.

    1989-01-01

    Nonlinear one-dimensional constant-profile hydromagnetic wave solutions are obtained in finite-temperature two-fluid collisionless plasmas under adiabatic equation of state. The nonlinear wave solutions can be classified according to the wavelength. The long-wavelength solutions are circularly polarized incompressible oblique Alfven wave trains with wavelength greater than hudreds of ion inertial length. The oblique wave train solutions can explain the high degree of alignment between the local average magnetic field and the wave normal direction observed in the solar wind. The short-wavelength solutions include rarefaction fast solitons, compression slow solitons, Alfven solitons and rotational discontinuities, with wavelength of several tens of ion inertial length, provided that the upstream flow speed is less than the fast-mode speed

  13. Dissipation of Alfven waves in compressible inhomogeneous media

    International Nuclear Information System (INIS)

    Malara, F.; Primavera, L.; Veltri, P.

    1997-01-01

    In weakly dissipative media governed by the magnetohydrodynamics (MHD) equations, any efficient mechanism of energy dissipation requires the formation of small scales. Using numerical simulations, we study the properties of Alfven waves propagating in a compressible inhomogeneous medium, with an inhomogeneity transverse to the direction of wave propagation. Two dynamical effects, energy pinching and phase mixing, are responsible for the small-scales formation, similarly to the incompressible case. Moreover, compressive perturbations, slow waves and a static entropy wave are generated; the former are subject to steepening and form shock waves, which efficiently dissipate their energy, regardless of the Reynolds number. Rough estimates show that the dissipation times are consistent with those required to dissipate Alfven waves of photospheric origin inside the solar corona

  14. Study on W-band sheet-beam traveling-wave tube based on flat-roofed sine waveguide

    Science.gov (United States)

    Fang, Shuanzhu; Xu, Jin; Jiang, Xuebing; Lei, Xia; Wu, Gangxiong; Li, Qian; Ding, Chong; Yu, Xiang; Wang, Wenxiang; Gong, Yubin; Wei, Yanyu

    2018-05-01

    A W-band sheet electron beam (SEB) traveling-wave tube (TWT) based on flat-roofed sine waveguide slow-wave structure (FRSWG-SWS) is proposed. The sine wave of the metal grating is replaced by a flat-roofed sine wave around the electron beam tunnel. The slow-wave characteristics including the dispersion properties and interaction impedance have been investigated by using the eigenmode solver in the 3-D electromagnetic simulation software Ansoft HFSS. Through calculations, the FRSWG SWS possesses the larger average interaction impedance than the conventional sine waveguide (SWG) SWS in the frequency range of 86-110 GHz. The beam-wave interaction was studied and particle-in-cell simulation results show that the SEB TWT can produce output power over 120 W within the bandwidth ranging from 90 to 100 GHz, and the maximum output power is 226 W at typical frequency 94 GHz, corresponding electron efficiency of 5.89%.

  15. ACG Clinical Guideline: Diagnosis and Management of Small Bowel Bleeding.

    Science.gov (United States)

    Gerson, Lauren B; Fidler, Jeff L; Cave, David R; Leighton, Jonathan A

    2015-09-01

    Bleeding from the small intestine remains a relatively uncommon event, accounting for ~5-10% of all patients presenting with gastrointestinal (GI) bleeding. Given advances in small bowel imaging with video capsule endoscopy (VCE), deep enteroscopy, and radiographic imaging, the cause of bleeding in the small bowel can now be identified in most patients. The term small bowel bleeding is therefore proposed as a replacement for the previous classification of obscure GI bleeding (OGIB). We recommend that the term OGIB should be reserved for patients in whom a source of bleeding cannot be identified anywhere in the GI tract. A source of small bowel bleeding should be considered in patients with GI bleeding after performance of a normal upper and lower endoscopic examination. Second-look examinations using upper endoscopy, push enteroscopy, and/or colonoscopy can be performed if indicated before small bowel evaluation. VCE should be considered a first-line procedure for small bowel investigation. Any method of deep enteroscopy can be used when endoscopic evaluation and therapy are required. VCE should be performed before deep enteroscopy if there is no contraindication. Computed tomographic enterography should be performed in patients with suspected obstruction before VCE or after negative VCE examinations. When there is acute overt hemorrhage in the unstable patient, angiography should be performed emergently. In patients with occult hemorrhage or stable patients with active overt bleeding, multiphasic computed tomography should be performed after VCE or CTE to identify the source of bleeding and to guide further management. If a source of bleeding is identified in the small bowel that is associated with significant ongoing anemia and/or active bleeding, the patient should be managed with endoscopic therapy. Conservative management is recommended for patients without a source found after small bowel investigation, whereas repeat diagnostic investigations are recommended

  16. Gastric emptying rate and small bowel transit time in patients with irritable bowel syndrome determined with 99mTc-labeled pellets and scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, O.H.; Gjorup, T.; Christensen, F.N.

    1986-12-01

    A new method employing 99mTc-labeled pellets for determination of the gastric emptying rate and small bowel transit time is described. The participants were six normal subjects and 16 patients with irritable bowel syndrome (eight with diarrhea and eight with obstipation as the primary complaint). The gastric emptying rate was the same in the three groups. The patients in the obstipation group had a significantly longer small bowel transit time than the normals (P less than 0.02) and the patients in the diarrhea group (P less than 0.01). There was no demonstrable difference between the small bowel transit time in the normals and in the patients in the diarrhea group.

  17. Gastric emptying rate and small bowel transit time in patients with irritable bowel syndrome determined with 99mTc-labeled pellets and scintigraphy

    International Nuclear Information System (INIS)

    Nielsen, O.H.; Gjorup, T.; Christensen, F.N.

    1986-01-01

    A new method employing 99mTc-labeled pellets for determination of the gastric emptying rate and small bowel transit time is described. The participants were six normal subjects and 16 patients with irritable bowel syndrome (eight with diarrhea and eight with obstipation as the primary complaint). The gastric emptying rate was the same in the three groups. The patients in the obstipation group had a significantly longer small bowel transit time than the normals (P less than 0.02) and the patients in the diarrhea group (P less than 0.01). There was no demonstrable difference between the small bowel transit time in the normals and in the patients in the diarrhea group

  18. Atividade lenta posterior: correlação eletro-clínica Posterior EEG slow activity: electro-clinical correlation

    Directory of Open Access Journals (Sweden)

    Salustiano Gomes Lins

    1971-06-01

    Full Text Available Inicialmente é feita breve exposição dos cinco principais tipos de atividade lenta posterior descritas na literatura eletrencefalográfica: variedade lenta do ritmo alfa, ritmo theta posterior, ondas lentas posteriores a 4 hertz, ritmo delta associado ao pequeno mal e ondas Pi. Em seguida o autor expõe seus achados, baseado num material clínico composto por 760 pacientes, colhidos ao acaso, dos dois sexos e com idades variáveis entre 5 e 24 anos. Excetuando a variedade lenta do ritmo alfa, um ou mais dos outros quatro grafo-elementos referidos foram observados em 131 destes pacientes (80 do sexo masculino e 51 do sexo feminino pertencentes aos 3 primeiros grupos etários (5 a 19 anos. Sua predominância no sexo masculino não alcançou nível de significação estatística, mas a maior incidência nos grupos de menor idade foi significativa a 0,01. O ritmo theta posterior associou-se significativamente apenas a distúrbios de conduta com forte agressividade. Dos 131 casos referidos, 10 eram portadores de pequeno mal e destes, 5 apresentavam ritmo delta posterior (3 do sexo masculino e 2 do sexo feminino. Apenas em dois casos foi observado o ritmo lento posterior a 4 hertz, ambos com comemorativos de traumatismo craniano, seguido de distúrbios da conduta e agressividade.The five principal types of posterior slow activity are reviwed: the slow alpha variant rhythm; the posterior theta rhythm; the posterior slow waves at 4 c/s; the delta rhythm associated with petit mal; the so called Pi waves. The results with EEG tracings of 760 patients of both sexes with ages between 5 and 24 years are reviewed. Except for the slow alpha variant, at least one of the four other phenomena as observed in 131 patients (80 males end 51 females. The theta rhythm was observed in 49 cases (29 males and 20 females. This higher frequence among the males is not significant but the higher frequence among the younger and the association with a clinical picture of

  19. Characterization of scale-free properties of human electrocorticography in awake and slow wave sleep states

    Directory of Open Access Journals (Sweden)

    John M Zempel

    2012-06-01

    Full Text Available Like many complex dynamic systems, the brain exhibits scale-free dynamics that follow power law scaling. Broadband power spectral density (PSD of brain electrical activity exhibits state-dependent power law scaling with a log frequency exponent that varies across frequency ranges. Widely divergent naturally occurring neural states, awake and slow wave sleep (SWS periods, were used evaluate the nature of changes in scale-free indices. We demonstrate two analytic approaches to characterizing electrocorticographic (ECoG data obtained during Awake and SWS states. A data driven approach was used, characterizing all available frequency ranges. Using an Equal Error State Discriminator (EESD, a single frequency range did not best characterize state across data from all six subjects, though the ability to distinguish awake and SWS states in individual subjects was excellent. Multisegment piecewise linear fits were used to characterize scale-free slopes across the entire frequency range (0.2-200 Hz. These scale-free slopes differed between Awake and SWS states across subjects, particularly at frequencies below 10 Hz and showed little difference at frequencies above 70 Hz. A Multivariate Maximum Likelihood Analysis (MMLA method using the multisegment slope indices successfully categorized ECoG data in most subjects, though individual variation was seen. The ECoG spectrum is not well characterized by a single linear fit across a defined set of frequencies, but is best described by a set of discrete linear fits across the full range of available frequencies. With increasing computational tractability, the use of scale-free slope values to characterize EEG data will have practical value in clinical and research EEG studies.

  20. Proctalgia fugax in patients with the irritable bowel, peptic ulcer, or inflammatory bowel disease.

    Science.gov (United States)

    Thompson, W G

    1984-06-01

    One hundred forty-eight patients with gastrointestinal disease, 50 patients with the irritable bowel syndrome (IBS) and 49 each with peptic ulcer and inflammatory bowel disease, were interviewed to determine if they had proctalgia fugax (PF) and if the symptom was associated with the IBS. One-third of the patients had PF. It occurred in 51% of females and 12% of males (p less than 0.001). When corrected for sex, PF was no more prevalent in IBS than in peptic ulcer or inflammatory bowel disease. Only two of six previously described IBS symptoms were more prevalent in the PF patients. Attacks occurred in the day in 94%, and one-third of sufferers related them to defecation. The pain was localized in the anus in 90%, occurred less than five times a year in 51%, and lasted less than 1 min in 57%. In most, activity was not interrupted by this pain and only 20% had ever reported it to a physician. PF is very common among patients with abdominal symptoms, but is not related to the IBS. Since it is infrequent, benign, and transient, PF is usually not mentioned to the physician.

  1. Radiographer performed single contrast small bowel enteroclysis

    International Nuclear Information System (INIS)

    Law, Robert L.; Slack, Nicola; Harvey, Richard F.

    2005-01-01

    Aim: To analyse the technical success and reporting sensitivity of radiographer performed small bowel enteroclysis (SBE) undertaken by a specialist radiographer according to a standard technique [Nolan DJ, Cadman PJ. The small bowel enema made easy. Clinical Radiology 1987;38(3):295-301]. Methods: Patients (1413) had 1646 SBE in 10 years from May 1992 to April 2002. The original request card and the separate radiographer and consultant radiologist reports were reviewed. Where the radiology reports were discordant or inconclusive, the clinical notes were also reviewed. Results: Patients (1022) X-ray films were available. Nine hundred and forty-three (93.3%) SBEs had been successfully completed. Radiographer and consultant radiologist reporting had a 99.3% concordance. There was a 98.4% sensitivity for Crohn's disease (181 of 184 cases where Crohn's disease was the clinical final diagnosis). Overall reporting sensitivity was 93.7% although correct 'probably normal and abnormal' reporting bias suggests a sensitivity of 96.9%. Sixty of 943 (6.4%) reports were inconclusive. Of 1022 patients, 68 (6.6%) of small bowel intubations were not achieved, or else consent was withdrawn at the time of the procedure. Conclusion: Specialist radiographers can perform small bowel enteroclysis with a reporting sensitivity equal to that of a consultant radiologist. Radiographers accustomed to providing an SBE service become skilled at passing fine bore feeding tubes into the small bowel and can provide this service also

  2. Small-bowel carcinoid with no liver metastases.

    Science.gov (United States)

    Juniku-Shkololli, Argjira; Haziri, Adem

    2009-01-01

    Carcinoid is a slowly-growing tumor from the group of neuroendocrine or APUD tumors. Characteristic of these tumors is the production of biogene amins & polypeptide hormones. 90% of all carcinoids are located in the GI system. A female patient, 68 years old, comes for a visit with signs of diffuse abdominal pain, diarrhea, irregular bowel movements, weakness, dyspnea and pretibial edemas. The gastroenterologist gives her only symptomatic therapy at first, and starts the examinations after her hospitalization (initial dg: Enterocolitis). One month later she visits again with the same complains. CT scan result shows steatosis hepatica and lots of liquids in the small bowel and colon. She underwent operation--resection of 20 cm of the small bowel with tumor masses and part-time ileostoma. The biopsy of the resected segment of the bowel shows multiple carcinoids. Our patient had no flushing of the skin and therefore couldn't be suspected clinically for this diagnosis. The intestinal carcinoid does not usually produce the carcionid syndrome unless hepatic metastases have occurred. The infiltration of the mesentery provokes an intense fibrotic reaction resulting in kinking of the bowel segments, which causes intestinal obstruction as it happened in this patient. As long as in our clinic we don't have this technique, it is much harder to make an early diagnosis. Fortunately our patient was diagnosed before liver metastases occurred, and therefore her treatment was successful.

  3. Plasma heating and confinement in toroidal magnetic bottle by means of microwave slowing-down structure

    International Nuclear Information System (INIS)

    Datlov, J.; Klima, R.; Kopecky, V.; Musil, J.; Zacek, F.

    1977-01-01

    An invention is described concerning high-frequency plasma heating and confinement in toroidal magnetic vessels. Microwave energy is applied to the plasma via one or more slowing-down structures exciting low phase velocity waves whose energy may be efficiently absorbed by plasma electrons. The wave momentum transfer results in a toroidal electrical current whose magnetic field together with an external magnetic field ensure plasma confinement. The low-frequency modulation of microwave energy may also be used for heating the ion plasma component. (J.U.)

  4. Modern treatment of short bowel syndrome

    DEFF Research Database (Denmark)

    Jeppesen, Palle B

    2013-01-01

    Recently, the US Food and Drug Administration and the European Medicines Agency approved the glucagon-like peptide 2 analogue, teduglutide, for the treatment of short bowel syndrome (SBS), and this review describes the physiological basis for its clinical use.......Recently, the US Food and Drug Administration and the European Medicines Agency approved the glucagon-like peptide 2 analogue, teduglutide, for the treatment of short bowel syndrome (SBS), and this review describes the physiological basis for its clinical use....

  5. Biofilms associated with bowel necrosis: A newly recognised ...

    African Journals Online (AJOL)

    All specimens showed varying degrees of bowel necrosis and an organising acute peritoneal reaction. In addition, all showed colonies of Gram-negative bacteria within a mucopolysaccharide matrix. Conclusions. The identification of biofilms in necrotic bowel has raised questions regarding their clinical implications. Further ...

  6. Higher curvature corrections to primordial fluctuations in slow-roll inflation

    International Nuclear Information System (INIS)

    Satoh, Masaki; Soda, Jiro

    2008-01-01

    We study higher curvature corrections to the scalar spectral index, the tensor spectral index, the tensor-to-scalar ratio, and the polarization of gravitational waves. We find that there are cases where the higher curvature corrections cannot be negligible in the dynamics of the scalar field, although they are always negligible energetically. Indeed, it turns out that the tensor-to-scalar ratio could be enhanced and the tensor spectral index could be blue due to the Gauss–Bonnet term. We estimate the degree of circular polarization of gravitational waves generated during the slow-roll inflation. We argue that the circular polarization could be observable with the help of both the Gauss–Bonnet and the parity violating terms. We also present several examples to reveal observational implications of higher curvature corrections for chaotic inflationary models

  7. Food, nutrients and nutraceuticals affecting the course of inflammatory bowel disease.

    Science.gov (United States)

    Uranga, José Antonio; López-Miranda, Visitación; Lombó, Felipe; Abalo, Raquel

    2016-08-01

    Inflammatory bowel diseases (ulcerative colitis; Crohn's disease) are debilitating relapsing inflammatory disorders affecting the gastrointestinal tract, with deleterious effect on quality of life, and increasing incidence and prevalence. Mucosal inflammation, due to altered microbiota, increased intestinal permeability and immune system dysfunction underlies the symptoms and may be caused in susceptible individuals by different factors (or a combination of them), including dietary habits and components. In this review we describe the influence of the Western diet, obesity, and different nutraceuticals/functional foods (bioactive peptides, phytochemicals, omega 3-polyunsaturated fatty acids, vitamin D, probiotics and prebiotics) on the course of IBD, and provide some hints that could be useful for nutritional guidance. Hopefully, research will soon offer enough reliable data to slow down the spread of the disease and to make diet a cornerstone in IBD therapy. Copyright © 2016 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  8. High frequency ion sound waves associated with Langmuir waves in type III radio burst source regions

    Directory of Open Access Journals (Sweden)

    G. Thejappa

    2004-01-01

    Full Text Available Short wavelength ion sound waves (2-4kHz are detected in association with the Langmuir waves (~15-30kHz in the source regions of several local type III radio bursts. They are most probably not due to any resonant wave-wave interactions such as the electrostatic decay instability because their wavelengths are much shorter than those of Langmuir waves. The Langmuir waves occur as coherent field structures with peak intensities exceeding the Langmuir collapse thresholds. Their scale sizes are of the order of the wavelength of an ion sound wave. These Langmuir wave field characteristics indicate that the observed short wavelength ion sound waves are most probably generated during the thermalization of the burnt-out cavitons left behind by the Langmuir collapse. Moreover, the peak intensities of the observed short wavelength ion sound waves are comparable to the expected intensities of those ion sound waves radiated by the burnt-out cavitons. However, the speeds of the electron beams derived from the frequency drift of type III radio bursts are too slow to satisfy the needed adiabatic ion approximation. Therefore, some non-linear process such as the induced scattering on thermal ions most probably pumps the beam excited Langmuir waves towards the lower wavenumbers, where the adiabatic ion approximation is justified.

  9. Pathophysiology of acute small bowel disease with CT correlation

    International Nuclear Information System (INIS)

    Sarwani, N.; Tappouni, R.; Tice, J.

    2011-01-01

    The objective of this article is to review the pathophysiology of acute small bowel diseases, and to correlate the mechanisms of disease with computed tomography (CT) findings. Disease entities will be classified into the following: immune mediated and infectious causes, vascular causes, mechanical causes, trauma, and others. Having an understanding of acute small bowel pathophysiology is a useful teaching tool, and can lead to imaging clues to the most likely diagnosis of acute small bowel disorders.

  10. Irregular wave functions of a hydrogen atom in a uniform magnetic field

    Science.gov (United States)

    Wintgen, D.; Hoenig, A.

    1989-01-01

    The highly excited irregular wave functions of a hydrogen atom in a uniform magnetic field are investigated analytically, with wave function scarring by periodic orbits considered quantitatively. The results obtained confirm that the contributions of closed classical orbits to the spatial wave functions vanish in the semiclassical limit. Their disappearance, however, is slow. This discussion is illustrated by numerical examples.

  11. Large Intraluminal Ileal Hematoma Presenting as Small Bowel Obstruction in a Child

    International Nuclear Information System (INIS)

    Lim, Yun Jung; Nam, So Hyun; Kim, Seon Jeong

    2015-01-01

    Intraluminal small bowel hematoma has been rarely reported in children, as a rare cause of small bowel obstruction. We present a case of an intraluminal ileal hematoma presenting as small bowel obstruction in a child. Computed Tomography (CT) indicated a large intraluminal hyperdense lesion in the distal ileum as the cause of small bowel obstruction. Abdominal ultrasonography (US) showed an echogenic mass-like lesion with multiple septa in the distal ileum. Small bowel obstruction due to a complicated cystic mass was provisionally diagnosed. Histopathologic examination of the resected mass suggested a submucosal ileal hematoma. Although intraluminal small bowel hematoma is rare in children, it can present as an intraluminal cystic mass and should be considered as a rare cause of small bowel obstruction. The US and CT findings of submucosal ileal hematoma could be useful for the diagnosis of such cases in the future

  12. Effects of electric stimulation of the hunger center in the lateral hypothalamus on slow electric activity and spike activity of fundal and antral stomach muscles in rabbits under conditions of hunger and satiation.

    Science.gov (United States)

    Kromin, A A; Zenina, O Yu

    2013-09-01

    In chronic experiments on rabbits, the effect of electric stimulation of the hunger center in the lateral hypothalamus on myoelectric activity of the fundal and antral parts of the stomach was studied under conditions of hunger and satiation in the absence of food. Stimulation of the lateral hypothalamus in rabbits subjected to 24-h food deprivation and in previously fed rabbits produced incessant seeking behavior, which was followed by reorganization of the structure of temporal organization of slow wave electric activity of muscles of the stomach body and antrum specific for hungry and satiated animals. Increased hunger motivation during electric stimulation of the lateral hypothalamus manifested in the structure of temporal organization of slow wave electric activity of the stomach body and antrum muscles in rabbits subjected to 24-h food deprivation in the replacement of bimodal distribution of slow wave periods to a trimodal type typical of 2-day deprivation, while transition from satiation to hunger caused by electric stimulation of the lateral hypothalamus was associated with a shift from monomodal distributions of slow wave periods to a bimodal type typical of 24-h deprivation. Reorganization of the structure of temporal organization of slow wave electric activity of the stomach body and antrum muscles during electric stimulation of the lateral hypothalamus was determined by descending inhibitory influences of food motivational excitation on activity of the myogenic pacemaker of the lesser curvature of the stomach.

  13. Confocal Laser Endomicroscopy in Inflammatory Bowel Disease

    DEFF Research Database (Denmark)

    Rasmussen, Ditlev Nytoft; Karstensen, John Gásdal; Riis, Lene Buhl

    2015-01-01

    included. Next, eligible studies were analysed with respect to several parameters, such as technique and clinical aim and definitions of outcomes. RESULTS: Confocal laser endomicroscopy has been used for a wide range of purposes in inflammatory bowel disease, covering assessment of inflammatory severity...... of confocal laser endomicroscopy for inflammatory bowel disease. METHODS: Available literature was searched systematically for studies applying confocal laser endomicroscopy in Crohn's disease or ulcerative colitis. Relevant literature was reviewed and only studies reporting original clinical data were...... of histological features such as colonic crypts, epithelial gaps and epithelial leakiness to fluorescein. CONCLUSIONS: Confocal laser endomicroscopy remains an experimental but emerging tool for assessment of inflammatory bowel disease. It is the only method that enables in vivo functional assessment...

  14. Effects of intestinal muscular wrapping on remnant intestinal motility after massive small bowel resection in conscious canines.

    Science.gov (United States)

    Uchiyama, M; Iwafuchi, M; Yagi, M; Iinuma, Y; Kanada, S; Ohtaki, M; Yamazaki, S; Homma, S

    2000-04-01

    We searched the effect of the muscular valve on the management of short bowel syndrome. The motility of the remnant intestine with a special muscular valve after 80% massive distal small bowel resection (MSBR) was evaluated in conscious dogs. The valve (muscular ring) was made by the autointestinal muscle layer holding vascular pedicle. Interdigestive and postprandial bowel motility using bipolar electrodes and/or contractile strain gauge force transducers 2-4 weeks after the surgery, and data of this group (Group I) were compared to the motility in dogs after MSBR without valve construction (Group II) and in controls (Control). Results; Fasting duodenal migrating myoelectric (or motor) complexes (MMCs) in Group I occurred at longer intervals than in Control and almost similarly to those in Group II. MMCs arising from the duodenum were often interrupted before the jejunum above the valve and the anastomosis. The velocity of duodenal MMC propagation was slowed in every intestinal segment including that from the duodenum to the proximal jejunum, and to the jejunum above the anastomosis. Transit time in MSBR group (I and II) from the duodenum to the terminal ileum was extremely shorter than in Control, but there were no differences between in Groups I and II. The duration of the postprandial period without duodenal MMCs in Group I was significantly prolonged than in Control, but was shorter than that in Group II. The muscular valve was frequently activated, and the jejunum covered with the valve was contracted frequently which synchronized with the valve activity. It seemed the valve worked as sphincter. However, intestinal obstruction was not occurred through the jejunum covered by the valve. In conclusion, changes in gut motility after MSBR with the valve construction compensate for the shortened intestine and maintain the bowel content earlier postoperatively in comparison with the MSBR alone, and also contribute to the adaptive increase in the remnant intestinal

  15. Slow Activity in Focal Epilepsy During Sleep and Wakefulness

    DEFF Research Database (Denmark)

    Pellegrino, Giovanni; Tombini, Mario; Curcio, Giuseppe

    2017-01-01

    Introduction We aimed to test differences between healthy subjects and patients with respect to slow wave activity during wakefulness and sleep. Methods Fifteen patients affected by nonlesional focal epilepsy originating within temporal areas and fourteen matched controls underwent a 24-hour EEG....... The effect was widespread for alpha band and above, while localized over the affected hemisphere for delta (sleep cycle 1, P = .006; sleep cycle 2, P = .008; sleep cycle 3, P = .017). The analysis of interhemispheric differences showed that the only frequency band stronger over the affected regions...

  16. Small bowel bacterial overgrowth

    Science.gov (United States)

    ... Surgical procedures that create a loop of small intestine where excess bacteria can grow. An example is a Billroth II type of stomach removal ( gastrectomy ). Some cases of irritable bowel syndrome (IBS).

  17. Absorption and dispersion of ultrasonic waves

    CERN Document Server

    Herzfeld, Karl F; Massey, H S W; Brueckner, Keith A

    1959-01-01

    Absorption and Dispersion of Ultrasonic Waves focuses on the influence of ultrasonics on molecular processes in liquids and gases, including hydrodynamics, energy exchange, and chemical reactions. The book first offers information on the Stokes-Navier equations of hydrodynamics, as well as equations of motion, viscosity, formal introduction of volume viscosity, and linearized wave equation for a nonviscous fluid. The manuscript then ponders on energy exchange between internal and external degrees of freedom as relaxation phenomenon; effect of slow energy exchange on sound propagation; differe

  18. Altered gastric emptying in patients with irritable bowel syndrome

    International Nuclear Information System (INIS)

    Caballero-Plasencia, A.M.; Valenzuela-Barranco, M.; Herrerias-Gutierrez, J.M.; Esteban-Carretero, J.M.

    1999-01-01

    Irritable bowel syndrome is the most frequent functional disorder of the digestive system. Patients with irritable bowel syndrome have motor disorders not only in the colon, but also in other parts of the digestive tract such as the oesophagus and small intestine; however, it is not known whether the stomach is also involved. We used a radiolabelled mixed solid-liquid meal (technetium-99m for the solid component, indium-111 for the liquid component) to study gastric emptying of solids (GES), liquids (GEL) and indigestible solids (GER) in 50 patients diagnosed as having irritable bowel syndrome (30 with predominant constipation and 20 with predominant diarrhoea). GER was measured by counting the number of indigestible solids remaining in the stomach 4 h after they were swallowed. In patients with irritable bowel syndrome, GES and GEL were slower than in control subjects (P<0.05). GER was normal in all patients except for two women. Thirty-two patients (64%) showed delayed GES, 29 (58%) delayed GEL, and 2 (4%) delayed GER. Among patients with irritable bowel syndrome, GES was slower in those with predominant constipation than in those with predominant diarrhoea (P<0.05); GEL and GER were similar in both groups. Gastroparesis was found in a large proportion of patients with irritable bowel syndrome, suggesting the presence of a more generalised motor disorder of the gut. (orig.)

  19. The Relationship between Irritable Bowel Syndrome, Depression, Anxiety, and Stress among Sample of Irritable Bowel Patients - Predictive Study

    OpenAIRE

    Osama Hasan Gaber

    2016-01-01

    This study aimed to examine the relationship of irritable bowel syndrome, anxiety, depression and stress among a sample of78 IBS patients (Rome III Diagnostic Criteria for Irritable Bowel Syndrome), anxiety symptoms scale, Depression symptoms scale, and stress scale (prepared by the researcher) were used Pearson Correlation Coefficient showed that there are statistically significant relationship between IBS and Anxiety, Depression and Stress (P?=0.01). The Regression and Prediction Coefficien...

  20. Increased risk for irritable bowel syndrome after acute diverticulitis.

    Science.gov (United States)

    Cohen, Erica; Fuller, Garth; Bolus, Roger; Modi, Rusha; Vu, Michelle; Shahedi, Kamyar; Shah, Rena; Atia, Mary; Kurzbard, Nicole; Sheen, Victoria; Agarwal, Nikhil; Kaneshiro, Marc; Yen, Linnette; Hodgkins, Paul; Erder, M Haim; Spiegel, Brennan

    2013-12-01

    Individuals with diverticulosis frequently also have irritable bowel syndrome (IBS), but there are no longitudinal data to associate acute diverticulitis with subsequent IBS, functional bowel disorders, or related emotional distress. In patients with postinfectious IBS, gastrointestinal disorders cause long-term symptoms, so we investigated whether diverticulitis might lead to IBS. We compared the incidence of IBS and functional bowel and related affective disorders among patients with diverticulitis. We performed a retrospective study of patients followed up for an average of 6.3 years at a Veteran's Administration medical center. Patients with diverticulitis were identified based on International Classification of Diseases, 9th revision codes, selected for the analysis based on chart review (cases, n = 1102), and matched with patients without diverticulosis (controls, n = 1102). We excluded patients with prior IBS, functional bowel, or mood disorders. We then identified patients who were diagnosed with IBS or functional bowel disorders after the diverticulitis attack, and controls who developed these disorders during the study period. We also collected information on mood disorders, analyzed survival times, and calculated adjusted hazard ratios. Cases were 4.7-fold more likely to be diagnosed later with IBS (95% confidence interval [CI], 1.6-14.0; P = .006), 2.4-fold more likely to be diagnosed later with a functional bowel disorder (95% CI, 1.6-3.6; P mood disorder (CI, 1.4-3.5; P IBS and functional bowel disorders. We propose calling this disorder postdiverticulitis IBS. Diverticulitis appears to predispose patients to long-term gastrointestinal and emotional symptoms after resolution of inflammation; in this way, postdiverticulitis IBS is similar to postinfectious IBS. Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.

  1. Slow light effect with high group index and wideband by saddle-like mode in PC-CROW

    Science.gov (United States)

    Wan, Yong; Jiang, Li-Jun; Xu, Sheng; Li, Meng-Xue; Liu, Meng-Nan; Jiang, Cheng-Yi; Yuan, Feng

    2018-04-01

    Slow light with high group index and wideband is achieved in photonic crystal coupled-resonator optical waveguides (PC-CROWs). According to the eye-shaped scatterers and various microcavities, saddle-like curves between the normalized frequency f and wave number k can be obtained by adjusting the parameters of the scatterers, parameters of the coupling microcavities, and positions of the scatterers. Slow light with decent flat band and group index can then be achieved by optimizing the parameters. Simulations prove that the maximal value of the group index is > 104, and the normalized delay bandwidth product within a new varying range of n g > 102 or n g > 103 can be a new and effective criterion of evaluation for the slow light in PC-CROWs.

  2. Hypothalamic digoxin, hemispheric chemical dominance, and inflammatory bowel disease.

    Science.gov (United States)

    Kurup, Ravi Kumar; Kurup, Parameswara Achutha

    2003-09-01

    The isoprenoid pathway produces three key metabolites--endogenous digoxin, dolichol, and ubiquinone. It was considered pertinent to assess the pathway in inflammatory bowel disease (ulcerative colitis and regional ileitis). Since endogenous digoxin can regulate neurotransmitter transport, the pathway and the related cascade were also assessed in individuals with differing hemispheric dominance to find out the role of hemispheric dominance in its pathogenesis. All the patients with inflammatory bowel disease were right-handed/left hemispheric dominant by the dichotic listening test. The following parameters were measured in patients with inflammatory bowel disease and in individuals with differing hemispheric dominance: (1) plasma HMG CoA reductase, digoxin, dolichol, ubiquinone, and magnesium levels; (2) tryptophan/tyrosine catabolic patterns; (3) free-radical metabolism; (4) glycoconjugate metabolism; and (5) membrane composition and RBC membrane Na+-K+ ATPase activity. Statistical analysis was done by ANOVA. In patients with inflammatory bowel disease there was elevated digoxin synthesis, increased dolichol and glycoconjugate levels, and low ubiquinone and elevated free radical levels. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites. There was an increase in cholesterol:phospholipid ratio and a reduction in glycoconjugate level of RBC membrane in these groups of patients. Inflammatory bowel disease is associated with an upregulated isoprenoid pathway and elevated digoxin secretion from the hypothalamus. This can contribute to immune activation, defective glycoprotein bowel antigen presentation, and autoimmunity and a schizophreniform psychosis important in its pathogenesis. The biochemical patterns obtained in inflammatory bowel disease is similar to those obtained in left-handed/right hemispheric dominant individuals by the dichotic listening test. But all the patients with peptic ulcer disease were right

  3. Advanced imaging techniques for small bowel Crohn's disease: what does the future hold?

    Science.gov (United States)

    Pita, Inês; Magro, Fernando

    2018-01-01

    Treatment of Crohn's disease (CD) is intrinsically reliant on imaging techniques, due to the preponderance of small bowel disease and its transmural pattern of inflammation. Ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI) are the most widely employed imaging methods and have excellent diagnostic accuracy in most instances. Some limitations persist, perhaps the most clinically relevant being the distinction between inflammatory and fibrotic strictures. In this regard, several methodologies have recently been tested in animal models and human patients, namely US strain elastography, shear wave elastography, contrast-enhanced US, magnetization transfer MRI and contrast dynamics in standard MRI. Technical advances in each of the imaging methods may expand their indications. The addition of oral contrast to abdominal US appears to substantially improve its diagnostic capabilities compared to standard US. Ionizing dose-reduction methods in CT can decrease concern about cumulative radiation exposure in CD patients and diffusion-weighted MRI may reduce the need for gadolinium contrast. Clinical indexes of disease activity and severity are also increasingly relying on imaging scores, such as the recently developed Lémann Index. In this review we summarize some of the recent advances in small bowel CD imaging and how they might affect clinical practice in the near future.

  4. An optimization method of relativistic backward wave oscillator using particle simulation and genetic algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zaigao; Wang, Jianguo [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Northwest Institute of Nuclear Technology, P.O. Box 69-12, Xi' an, Shaanxi 710024 (China); Wang, Yue; Qiao, Hailiang; Zhang, Dianhui [Northwest Institute of Nuclear Technology, P.O. Box 69-12, Xi' an, Shaanxi 710024 (China); Guo, Weijie [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China)

    2013-11-15

    Optimal design method of high-power microwave source using particle simulation and parallel genetic algorithms is presented in this paper. The output power, simulated by the fully electromagnetic particle simulation code UNIPIC, of the high-power microwave device is given as the fitness function, and the float-encoding genetic algorithms are used to optimize the high-power microwave devices. Using this method, we encode the heights of non-uniform slow wave structure in the relativistic backward wave oscillators (RBWO), and optimize the parameters on massively parallel processors. Simulation results demonstrate that we can obtain the optimal parameters of non-uniform slow wave structure in the RBWO, and the output microwave power enhances 52.6% after the device is optimized.

  5. Stochastic dynamic modeling of regular and slow earthquakes

    Science.gov (United States)

    Aso, N.; Ando, R.; Ide, S.

    2017-12-01

    Both regular and slow earthquakes are slip phenomena on plate boundaries and are simulated by a (quasi-)dynamic modeling [Liu and Rice, 2005]. In these numerical simulations, spatial heterogeneity is usually considered not only for explaining real physical properties but also for evaluating the stability of the calculations or the sensitivity of the results on the condition. However, even though we discretize the model space with small grids, heterogeneity at smaller scales than the grid size is not considered in the models with deterministic governing equations. To evaluate the effect of heterogeneity at the smaller scales we need to consider stochastic interactions between slip and stress in a dynamic modeling. Tidal stress is known to trigger or affect both regular and slow earthquakes [Yabe et al., 2015; Ide et al., 2016], and such an external force with fluctuation can also be considered as a stochastic external force. A healing process of faults may also be stochastic, so we introduce stochastic friction law. In the present study, we propose a stochastic dynamic model to explain both regular and slow earthquakes. We solve mode III problem, which corresponds to the rupture propagation along the strike direction. We use BIEM (boundary integral equation method) scheme to simulate slip evolution, but we add stochastic perturbations in the governing equations, which is usually written in a deterministic manner. As the simplest type of perturbations, we adopt Gaussian deviations in the formulation of the slip-stress kernel, external force, and friction. By increasing the amplitude of perturbations of the slip-stress kernel, we reproduce complicated rupture process of regular earthquakes including unilateral and bilateral ruptures. By perturbing external force, we reproduce slow rupture propagation at a scale of km/day. The slow propagation generated by a combination of fast interaction at S-wave velocity is analogous to the kinetic theory of gasses: thermal

  6. Biofilms associated with bowel necrosis: A newly recognised ...

    African Journals Online (AJOL)

    role of biofilms has been established for oral infections, chronic wounds, indwelling ... bowel in infants and may be of significance in the pathogenesis of bowel necrosis and the ... implications in the understanding of the disease process. .... showed areas of mucosal ulceration and ... venous and urinary catheters, and dental.

  7. Ultrasonic inspection of studs (bolts) using dynamic predictive deconvolution and wave shaping.

    Science.gov (United States)

    Suh, D M; Kim, W W; Chung, J G

    1999-01-01

    Bolt degradation has become a major issue in the nuclear industry since the 1980's. If small cracks in stud bolts are not detected early enough, they grow rapidly and cause catastrophic disasters. Their detection, despite its importance, is known to be a very difficult problem due to the complicated structures of the stud bolts. This paper presents a method of detecting and sizing a small crack in the root between two adjacent crests in threads. The key idea is from the fact that the mode-converted Rayleigh wave travels slowly down the face of the crack and turns from the intersection of the crack and the root of thread to the transducer. Thus, when a crack exists, a small delayed pulse due to the Rayleigh wave is detected between large regularly spaced pulses from the thread. The delay time is the same as the propagation delay time of the slow Rayleigh wave and is proportional to the site of the crack. To efficiently detect the slow Rayleigh wave, three methods based on digital signal processing are proposed: wave shaping, dynamic predictive deconvolution, and dynamic predictive deconvolution combined with wave shaping.

  8. Small-bowel neoplasms in patients undergoing video capsule endoscopy

    DEFF Research Database (Denmark)

    Rondonotti, E; Pennazio, M; Toth, E

    2008-01-01

    BACKGROUND AND STUDY AIM: Small-bowel tumors account for 1% - 3% of all gastrointestinal neoplasms. Recent studies with video capsule endoscopy (VCE) suggest that the frequency of these tumors may be substantially higher than previously reported. The aim of the study was to evaluate the frequency......, clinical presentation, diagnostic/therapeutic work-up, and endoscopic appearance of small-bowel tumors in a large population of patients undergoing VCE. PATIENTS AND METHODS: Identification by a questionnaire of patients with VCE findings suggesting small-bowel tumors and histological confirmation...... of the neoplasm seen in 29 centers of 10 European Countries. RESULTS: Of 5129 patients undergoing VCE, 124 (2.4%) had small-bowel tumors (112 primary, 12 metastatic). Among these patients, indications for VCE were: obscure gastrointestinal bleeding (108 patients), abdominal pain (9), search for primary neoplasm...

  9. Characteristics of neurogenic bowel in spinal cord injury and perceived quality of life.

    Science.gov (United States)

    Pardee, Connie; Bricker, Diedre; Rundquist, Jeanine; MacRae, Christi; Tebben, Cherisse

    2012-01-01

    To investigate the association between characteristics of individuals with spinal cord injury and neurogenic bowel and their perceived quality of life. The study design is an exploratory, descriptive correlational design. To measure the variables of the study the Quality of Life Survey developed by Randell et al. (2001) was used to measure perceived quality of life related to bowel management. Individual bowel management preferences and subjective costs and benefits of the preferences were gathered through the Neurogenic Bowel Characteristics Survey. PARTICIPANTS/METHOD: Data were collected from a random half of the individuals who met the inclusion criteria from the patient database (n=1193). Two hundred and forty one surveys were analyzed for this study. More than half of the sample (n=134) provided their own bowel management consisting of digital stimulation, suppositories, and other aids; 8% (n=19) had a colostomy. Regardless of the bowel management program 54% (n=127) were satisfied with current methods. Although time reported to complete bowel programs ranged from 1 to 120 minutes, there was no difference in rating of satisfaction with time. There was a statistically significant difference between those satisfied and dissatisfied with current bowel management and quality of life; those satisfied demonstrated a higher quality of life on three subscales, work function (p= .021), bowel problems (p< .001), and social function (p< .001). Those dissatisfied with their bowel program perceived a lower quality of life and indicated problems of time (p= .001), pain or discomfort (p= .033), and poor results (p< .001). Research data provide the patient's perspective on bowel management characteristics, complications, satisfaction, and their perceived quality of life. Results of this research will be incorporated into bowel management education and possible modification of the current inpatient bowel management program. © 2012 Association of Rehabilitation Nurses.

  10. Development of a bowel function assessment tool to measure bowel function in patients receiving radiation and/or chemotherapy

    International Nuclear Information System (INIS)

    Throckmorton, Terry; Janjan, Nora; Bisanz, Annette; Pearce, Ann Nette; Bevins, Melinda; DeFord, Linda; Skibber, John; Abbruzzese, James; Rich, Tyvin

    1997-01-01

    PURPOSE/OBJECTIVE: One of the goals in the treatment of gastrointestinal tract malignancies is to preserve normal bowel function. Evaluation of bowel function to date, however, has been highly subjective and restricted in definition. Presented is a tool that has been validated for use as a more specific assessment of bowel function after therapeutic intervention. MATERIALS AND METHODS: The Bowel Function Self Assessment Tool [BFSAT] was developed from descriptive data obtained from cancer patients who presented with problems related to bowel function. The BFSAT and FACT-C scale were administered to 134 patients with colorectal cancer. Prior treatment had included radiation, administered either alone or in combination with chemotherapy, following surgical resection. RESULTS: Content validity was achieved through the multimodality review panel process. Based on descriptors provided by patients, publications and a multimodality review panel who screened the items for clarity and content, 29 of the initial 40 items were unanimously agreed upon and included in the questionnaire. A correlation of 0.51, which is significant beyond the 0.001 level, was obtained between the BFSAT and the FACT-C, indicating strong concurrent validity. The internal consistency and reliability was confirmed by coefficient alpha levels of 0.85, which matched the 0.85 coefficient alpha level for the FACT-C scale in this population. Factor analysis will be conducted when a larger sample size is available. CONCLUSION: Baseline reliability and validity have been established for the BFSAT. The BFSAT shows strong correlation with the FACT-C scale. Providing information regarding function and clinical outcome, the BFSAT complements the FACT-C in the evaluation of quality of life parameters among patients with colorectal cancer

  11. The pathophysiology of the nodular and micronodular small bowel fold

    International Nuclear Information System (INIS)

    Olmsted, W.W.; Ros, P.R.; Moser, R.P.; Shekita, K.M.; Lichtenstein, J.E.

    1986-01-01

    The normal small bowel fold is easily seen on conventional studies of the small intestine, but visualization of the small bowel villus is at the limit of resolution of current roentgenographic technique. When the villi are enlarged, they appear radiographically as an irregularity or micronodularity of the small bowel fold. The anatomy of the fold and the pathophysiology of diseases producing fold nodularity (tumor,inflammatory disease, NLH, mastocytosis) and micronodularity (lymphangiectasia, Waldenstrom macroglobulinemia, Whipple disease) are presented, with an emphasis on radiologic-pathologic correlation. The radiologist should suggest certain diseases or conditions based on the roentgenographic characteristics of the closely analyzed small bowel fold

  12. Predictors of Bowel Function in Long-term Rectal Cancer Survivors with Anastomosis.

    Science.gov (United States)

    Alavi, Mubarika; Wendel, Christopher S; Krouse, Robert S; Temple, Larissa; Hornbrook, Mark C; Bulkley, Joanna E; McMullen, Carmit K; Grant, Marcia; Herrinton, Lisa J

    2017-11-01

    Bowel function in long-term rectal cancer survivors with anastomosis has not been characterized adequately. We hypothesized that bowel function is associated with patient, disease, and treatment characteristics. The cohort study included Kaiser Permanente members who were long-term (≥5 years) rectal cancer survivors with anastomosis. Bowel function was scored using the self-administered, 14-item Memorial Sloan-Kettering Cancer Center Bowel Function Index. Patient, cancer, and treatment variables were collected from the electronic medical chart. We used multiple regression to assess the relationship of patient- and treatment-related variables with the bowel function score. The study included 381 anastomosis patients surveyed an average 12 years after their rectal cancer surgeries. The total bowel function score averaged 53 (standard deviation, 9; range, 31-70, higher scores represent better function). Independent factors associated with worse total bowel function score included receipt of radiation therapy (yes vs. no: 5.3-unit decrement, p 6 cm: 3.2-unit decrement, p decrement, p decrement, p model explained 20% of the variation in the total bowel function score. Low tumor location, radiation therapy, temporary ostomy during initial treatment, and history of smoking were linked with decreased long-term bowel function following an anastomosis. These results should improve decision-making about surgical options.

  13. Functional bowel disorders and functional abdominal pain

    OpenAIRE

    Thompson, W; Longstreth, G; Drossman, D; Heaton, K; Irvine, E; Muller-Lissner, S

    1999-01-01

    The Rome diagnostic criteria for the functional bowel disorders and functional abdominal pain are used widely in research and practice. A committee consensus approach, including criticism from multinational expert reviewers, was used to revise the diagnostic criteria and update diagnosis and treatment recommendations, based on research results. The terminology was clarified and the diagnostic criteria and management recommendations were revised. A functional bowel disorder (FBD) is diagnosed ...

  14. Mechanical bowel preparation for elective colorectal surgery

    DEFF Research Database (Denmark)

    Güenaga, Katia F; Matos, Delcio; Wille-Jørgensen, Peer

    2011-01-01

    The presence of bowel contents during colorectal surgery has been related to anastomotic leakage, but the belief that mechanical bowel preparation (MBP) is an efficient agent against leakage and infectious complications is based on observational data and expert opinions only.An enema before...... the rectal surgery to clean the rectum and facilitate the manipulation for the mechanical anastomosis is used for many surgeons. This is analysed separately...

  15. 111In autologous leucocytes in the diagnosis and assessment of inflammatory bowel disease

    International Nuclear Information System (INIS)

    Saverymuttu, S.H.; Peters, A.M.; Reavy, H.J.; Danpure, H.J.; Osman, S.; Chadwick, V.S.; Hodgson, H.J.; Lavender, J.P.

    1982-01-01

    111 In-labelled leucocytes were used to obtain gamma camera images of inflamed of bowel in a wide variety of inflammatory bowel disease. No false positive scans were observed in the irritable bowel syndrome and in bowel malignancy. All patients with moderate or severely active disease had positive scans. Faecal excretion of 111 Indium increased with disease severity. 111 In-tropolone labelling appeared to offer the advantage over 111 In-acac labelling in localising inflamed bowel earlier. In many cases the bowel was imaged within 40 min of re-injection of the leucocytes. 111 In-leucocyte scanning provides a novel approach to the problem of diagnosis and assessment of inflammatory bowel disease. It is non-invasive, requires no bowel preparation and thus is safe in the acutely sick patient where conventional radiological imaging methods may be hazardous. 111 Indium faecal excretion provides an objective assessment of disease activity which should prove useful in evaluating treatment regimes

  16. Revealing the cluster of slow transients behind a large slow slip event.

    Science.gov (United States)

    Frank, William B; Rousset, Baptiste; Lasserre, Cécile; Campillo, Michel

    2018-05-01

    Capable of reaching similar magnitudes to large megathrust earthquakes [ M w (moment magnitude) > 7], slow slip events play a major role in accommodating tectonic motion on plate boundaries through predominantly aseismic rupture. We demonstrate here that large slow slip events are a cluster of short-duration slow transients. Using a dense catalog of low-frequency earthquakes as a guide, we investigate the M w 7.5 slow slip event that occurred in 2006 along the subduction interface 40 km beneath Guerrero, Mexico. We show that while the long-period surface displacement, as recorded by Global Positioning System, suggests a 6-month duration, the motion in the direction of tectonic release only sporadically occurs over 55 days, and its surface signature is attenuated by rapid relocking of the plate interface. Our proposed description of slow slip as a cluster of slow transients forces us to re-evaluate our understanding of the physics and scaling of slow earthquakes.

  17. Fast Plane Wave Imaging

    DEFF Research Database (Denmark)

    Jensen, Jonas

    This PhD project investigates and further develops methods for ultrasound plane wave imaging and blood flow estimation with the objective of overcoming some of the major limitations in conventional ultrasound systems, which are related to low frame rates and only estimation of velocities along...... the ultrasound beam. The first part of the contribution investigates the compromise between frame rate and plane wave image quality including the influence of grating lobes from a λ-pitch transducer. A method for optimizing the image quality is suggested, and it is shown that the frame rate can be increased...... healthy volunteers. Complex flow patterns were measured in an anthropomorphic flow phantom and showed good agreement with the velocity field simulated using computational fluid dynamics. The last part of the contribution investigates two clinical applications. Plane wave imaging was used for slow velocity...

  18. Advances in the treatment of malignant large-bowel obstruction

    African Journals Online (AJOL)

    2007-07-19

    Jul 19, 2007 ... Most cases of large-bowel obstruction are due to colonic adeno- carcinoma. 324 ... to perforation and faeculent peritonitis. .... advance in emergency colorectal surgery has been the .... where there is clinical suspicion of bowel.

  19. Radiologic examination of the small bowel: 1987

    International Nuclear Information System (INIS)

    Carlson, H.C.; Maglinte, D.D.T.

    1987-01-01

    Effective clinical imaging of the small intestine is accomplished only with methods capable of accurately demonstrating bowel morphology. The two major approaches to barium enema examination of this segment of gut - orally and enteroclysis - will be described and illustrated with short videotape presentations. Pursued vigorously and with interest, both methods can yield excellent results in an efficient manner. Careful execution of the examination rather than use of a particular methodology is probably the most important factor in realizing such results. However, each method has its advantages and disadvantages, and these will be presented and discussed. A cursory small bowel examination has no role in modern medicine. Radiologists assume primary responsibility for the diagnostic evaluation of the small bowel and should strive to refine and advance the accuracy of the examination

  20. Finite Amplitude Electron Plasma Waves in a Cylindrical Waveguide

    DEFF Research Database (Denmark)

    Juul Rasmussen, Jens

    1978-01-01

    The nonlinear behaviour of the electron plasma wave propagating in a cylindrical plasma waveguide immersed in an infinite axial magnetic field is investigated using the Krylov-Bogoliubov-Mitropolsky perturbation method, by means of which is deduced the nonlinear Schrodinger equation governing...... the long-time slow modulation of the wave amplitude. From this equation the amplitude-dependent frequency and wavenumber shifts are calculated, and it is found that the electron waves with short wavelengths are modulationally unstable with respect to long-wavelength, low-frequency perturbations...

  1. Small Bowel Follow-Through

    Science.gov (United States)

    ... Small bowel follow-through uses a form of real-time x-ray called fluoroscopy and a barium-based ... Dense bone absorbs much of the radiation while soft tissue, such as muscle, fat and organs, allow ...

  2. The effect of obesity levels on irradiated small bowel volume in belly board with small bowel displacement device for rectal cancer radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Se Young; Kim, Joo Ho; Park, Hyo Kuk; Cho, Jeong Hee [Dept. of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System, Seoul (Korea, Republic of)

    2013-03-15

    For radiotherapy in rectal cancer patients treated with small bowel displacement device (SBDD) and belly board, We will suggest new indication of using SBDD depending on obesity index by analyzing correlation between obesity and irradiated small bowel volume. In this study, We reviewed 29 rectal cancer patients who received pelvic radiation therapy with belly board and SBDD from January to April in 2012. We only analyzed those patients treated with three-field technique (PA and both LAT) on 45 Gy (1.8 Gy/fx). We measured patients' height, weight, body mass index (BMI), waist-hip ratio (WHR) and divided BMI into two groups.(≥23:BMI=group 1, <23:BMI=group 2) We performed a statistical analysis to evaluate correlation between total volume of bladder (TV{sub bldder}), obesity index and high dose volume of small bowel (small bowel volume irradiated at 90% of prescribed dose, HDV{sub sb}), low dose volume of small bowel (small bowel volume irradiated at 33% of prescribed dose, LDV{sub sb}). The result shows, gender, WHR and status of pre operative or post operative do not greatly affect HDV{sub sb} and LDV{sub sb}. Statistical result shows, there are significant correlation between HDV{sub sb} and BMI (p<0.04), HDV{sub sb} and TV{sub bladder} (p<0.01), LDV{sub sb} and TV{sub bladder} (p<0.01). BMI seems to correlate with HDV{sub sb} but does not with LDV{sub sb} (p>0.05). There are negative correlation between HDV{sub sb} and BMI, TV{sub bladder} and HDV{sub sb}, TV{sub bladder} and LDV{sub sb} . Especially, BMI group1 has more effective and negative correlation with HDV{sub sb} (p=0.027) than in BMI group 2. In the case of BMI group 1, TV{sub bladder} has significant negative correlation with HDV{sub sb} and LDV{sub sb} (p<0.04). In conclusions, we confirmed that Using SBDD with belly board in BMI group 1 could more effectively reduce irradiated small bowel volume in radiation therapy for rectal cancer. Therefore, We suggest using belly board with SBDD in order

  3. The effect of obesity levels on irradiated small bowel volume in belly board with small bowel displacement device for rectal cancer radiotherapy

    International Nuclear Information System (INIS)

    Kim, Se Young; Kim, Joo Ho; Park, Hyo Kuk; Cho, Jeong Hee

    2013-01-01

    For radiotherapy in rectal cancer patients treated with small bowel displacement device (SBDD) and belly board, We will suggest new indication of using SBDD depending on obesity index by analyzing correlation between obesity and irradiated small bowel volume. In this study, We reviewed 29 rectal cancer patients who received pelvic radiation therapy with belly board and SBDD from January to April in 2012. We only analyzed those patients treated with three-field technique (PA and both LAT) on 45 Gy (1.8 Gy/fx). We measured patients' height, weight, body mass index (BMI), waist-hip ratio (WHR) and divided BMI into two groups.(≥23:BMI=group 1, <23:BMI=group 2) We performed a statistical analysis to evaluate correlation between total volume of bladder (TV bldder ), obesity index and high dose volume of small bowel (small bowel volume irradiated at 90% of prescribed dose, HDV sb ), low dose volume of small bowel (small bowel volume irradiated at 33% of prescribed dose, LDV sb ). The result shows, gender, WHR and status of pre operative or post operative do not greatly affect HDV sb and LDV sb . Statistical result shows, there are significant correlation between HDV sb and BMI (p<0.04), HDV sb and TV bladder (p<0.01), LDV sb and TV bladder (p<0.01). BMI seems to correlate with HDV sb but does not with LDV sb (p>0.05). There are negative correlation between HDV sb and BMI, TV bladder and HDV sb , TV bladder and LDV sb . Especially, BMI group1 has more effective and negative correlation with HDV sb (p=0.027) than in BMI group 2. In the case of BMI group 1, TV bladder has significant negative correlation with HDV sb and LDV sb (p<0.04). In conclusions, we confirmed that Using SBDD with belly board in BMI group 1 could more effectively reduce irradiated small bowel volume in radiation therapy for rectal cancer. Therefore, We suggest using belly board with SBDD in order to reduce the small bowel toxicity in rectal radiotherapy, if patients' BMI is above 23

  4. On the theory of wave packets

    International Nuclear Information System (INIS)

    Naumov, D.V.

    2013-01-01

    In this paper we discuss some aspects of the theory of wave packets. We consider a popular non-covariant Gaussian model used in various applications and show that it predicts too slow a longitudinal dispersion rate for relativistic particles. We revise this approach by considering a covariant model of Gaussian wave packets, and examine our results by inspecting a wave packet of an arbitrary form. A general formula for the time dependence of the dispersion of a wave packet of an arbitrary form is found. Finally, we give a transparent interpretation of the disappearance of the wave function over time due to the dispersion - a feature often considered undesirable, but which is unavoidable for wave packets. We find, starting with simple examples, proceeding with their generalizations and finally by considering the continuity equation, that the integral over time of both the flux and probability densities is asymptotically proportional to the factor 1/|x| 2 in the rest frame of the wave packet, just as in the case of an ensemble of classical particles

  5. High energy particle acceleration by relativistic plasma waves

    International Nuclear Information System (INIS)

    Amiranoff, F.; Jacquet, F.; Mora, P.; Matthieussent, G.

    1991-01-01

    Accelerating schemes using plasmas, lasers or electron beams are proposed and compared to electron bunches in dielectric media or laser propagation through a slow wave structure made of liquid droplets. (L.C.J.A.). 33 refs, 20 figs

  6. An Extreme-ultraviolet Wave Generating Upward Secondary Waves in a Streamer-like Solar Structure

    Science.gov (United States)

    Zheng, Ruisheng; Chen, Yao; Feng, Shiwei; Wang, Bing; Song, Hongqiang

    2018-05-01

    Extreme-ultraviolet (EUV) waves, spectacular horizontally propagating disturbances in the low solar corona, always trigger horizontal secondary waves (SWs) when they encounter the ambient coronal structure. We present the first example of upward SWs in a streamer-like structure after the passing of an EUV wave. This event occurred on 2017 June 1. The EUV wave happened during a typical solar eruption including a filament eruption, a coronal mass ejection (CME), and a C6.6 flare. The EUV wave was associated with quasi-periodic fast propagating (QFP) wave trains and a type II radio burst that represented the existence of a coronal shock. The EUV wave had a fast initial velocity of ∼1000 km s‑1, comparable to high speeds of the shock and the QFP wave trains. Intriguingly, upward SWs rose slowly (∼80 km s‑1) in the streamer-like structure after the sweeping of the EUV wave. The upward SWs seemed to originate from limb brightenings that were caused by the EUV wave. All of the results show that the EUV wave is a fast-mode magnetohydrodynamic (MHD) shock wave, likely triggered by the flare impulses. We suggest that part of the EUV wave was probably trapped in the closed magnetic fields of the streamer-like structure, and upward SWs possibly resulted from the release of slow-mode trapped waves. It is believed that the interplay of the strong compression of the coronal shock and the configuration of the streamer-like structure is crucial for the formation of upward SWs.

  7. Finite element analysis of surface acoustic waves in high aspect ratio electrodes

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    2008-01-01

    This paper elaborates on how the finite element method is employed to model surface acoustic waves generated by high aspect ratio electrodes and their interaction with optical waves in a waveguide. With a periodic model it is shown that these electrodes act as a mechanical resonator which slows...

  8. Analysis of 178 penetrating stomach and small bowel injuries.

    Science.gov (United States)

    Salim, Ali; Teixeira, Pedro G R; Inaba, Kenji; Brown, Carlos; Browder, Timothy; Demetriades, Demetrios

    2008-03-01

    Surgical site infections (SSIs), such as wound infection, fascial dehiscence, and intraabdominal abscess, commonly occur following penetrating abdominal trauma. However, most of the literature involves penetrating colon injuries. There are few reports describing complications following penetrating stomach and small bowel injuries. Based on the hypothesis that SSIs are commonly found following penetrating stomach and small bowel trauma, a prospective observational study was performed at an academic Level I trauma center from March 1, 2004 until August 31, 2006. The subjects were patients who had sustained a penetrating injury to the stomach or small bowel. Patients were followed for the development of an SSI, defined as wound infection, fascial dehiscence, or intraabdominal abscess. A total of 178 patients were admitted with penetrating stomach or small bowel injuries over the 29-month period. There were 121 (68%) gunshot injuries and 57 (32%) stab wounds. Associated intraabdominal injuries occurred in 74% of patients. Overall, SSIs occurred in 20% of cases. Risk factors for SSI included associated duodenal or colon injury, whereas time to operating room, blood loss, and type and duration of antibiotic use were not. When associated colon injuries were excluded, SSIs occurred in 16% of patients with gastric injuries and 13% of those with small bowel injuries. SSIs commonly follow penetrating stomach and small bowel trauma. Risk factors for SSI include associated duodenal or colon injury. Delay to operating room, blood loss, and type and length of antibiotic prophylaxis were not associated with an increased risk of SSI.

  9. Altered gastric emptying in patients with irritable bowel syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Caballero-Plasencia, A.M.; Valenzuela-Barranco, M. [Department of Medicine, School of Medicine, University of Granada (Spain); Herrerias-Gutierrez, J.M. [Division of Gastroenterology, University Hospital ``Virgen de la Macarena``, Sevilla (Spain); Esteban-Carretero, J.M. [Central Service of Investigation in Health Sciences, University of Cadiz, Cadiz (Spain)

    1999-04-29

    Irritable bowel syndrome is the most frequent functional disorder of the digestive system. Patients with irritable bowel syndrome have motor disorders not only in the colon, but also in other parts of the digestive tract such as the oesophagus and small intestine; however, it is not known whether the stomach is also involved. We used a radiolabelled mixed solid-liquid meal (technetium-99m for the solid component, indium-111 for the liquid component) to study gastric emptying of solids (GES), liquids (GEL) and indigestible solids (GER) in 50 patients diagnosed as having irritable bowel syndrome (30 with predominant constipation and 20 with predominant diarrhoea). GER was measured by counting the number of indigestible solids remaining in the stomach 4 h after they were swallowed. In patients with irritable bowel syndrome, GES and GEL were slower than in control subjects (P<0.05). GER was normal in all patients except for two women. Thirty-two patients (64%) showed delayed GES, 29 (58%) delayed GEL, and 2 (4%) delayed GER. Among patients with irritable bowel syndrome, GES was slower in those with predominant constipation than in those with predominant diarrhoea (P<0.05); GEL and GER were similar in both groups. Gastroparesis was found in a large proportion of patients with irritable bowel syndrome, suggesting the presence of a more generalised motor disorder of the gut. (orig.) With 1 fig., 3 tabs., 48 refs.

  10. The effects of leptin on REM sleep and slow wave delta in rats are reversed by food deprivation.

    Science.gov (United States)

    Sinton, C M; Fitch, T E; Gershenfeld, H K

    1999-09-01

    Leptin (ob protein) is an adipose tissue derived circulating hormone that acts at specific receptors in the hypothalamus to reduce food intake. The protein is also critically involved in energy balance and metabolic status. Here the effect of leptin on sleep architecture in rats was evaluated because food consumption and metabolic status are known to influence sleep. Sprague-Dawley rats were chronically implanted with electrodes for EEG and EMG recording and diurnal sleep parameters were quantified over 9-h periods following leptin administration. Murine recombinant leptin (rMuLep) was administered systemically to rats that either had undergone 18 h of prior food deprivation or had received food ad libitum. In the normally fed rats, leptin significantly decreased the duration of rapid eye movement sleep (REMS) by about 30% and increased the duration of slow wave sleep (SWS) by about 13%, the latter effect reflecting enhanced power in the delta frequency band. These results are consistent with studies that have linked changes in metabolic rate with effects on sleep. Leptin administration has previously been shown to alter neuroendocrine parameters that could have mediated these changes in sleep architecture. Unexpectedly, prior food deprivation negated the effect of leptin on both REMS and SWS, a result that emphasizes the significance of the apparent coupling between sleep parameters and energy status.

  11. Density Fluctuations in the Solar Wind Driven by Alfvén Wave Parametric Decay

    Science.gov (United States)

    Bowen, Trevor A.; Badman, Samuel; Hellinger, Petr; Bale, Stuart D.

    2018-02-01

    Measurements and simulations of inertial compressive turbulence in the solar wind are characterized by anti-correlated magnetic fluctuations parallel to the mean field and density structures. This signature has been interpreted as observational evidence for non-propagating pressure balanced structures, kinetic ion-acoustic waves, as well as the MHD slow-mode. Given the high damping rates of parallel propagating compressive fluctuations, their ubiquity in satellite observations is surprising and suggestive of a local driving process. One possible candidate for the generation of compressive fluctuations in the solar wind is the Alfvén wave parametric instability. Here, we test the parametric decay process as a source of compressive waves in the solar wind by comparing the collisionless damping rates of compressive fluctuations with growth rates of the parametric decay instability daughter waves. Our results suggest that generation of compressive waves through parametric decay is overdamped at 1 au, but that the presence of slow-mode-like density fluctuations is correlated with the parametric decay of Alfvén waves.

  12. Altered neurotransmitter expression profile in the ganglionic bowel in Hirschsprung's disease.

    Science.gov (United States)

    Coyle, David; O'Donnell, Anne Marie; Gillick, John; Puri, Prem

    2016-05-01

    Despite having optimal pull-through (PT) surgery for Hirschsprung's disease (HSCR), many patients experience persistent bowel symptoms with no mechanical/histopathological cause. Murine models of HSCR suggest that expression of key neurotransmitters is unbalanced proximal to the aganglionic colonic segment. We aimed to investigate expression of key enteric neurotransmitters in the colon of children with HSCR. Full-length PT specimens were collected fresh from children with HSCR (n=10). Control specimens were collected at colostomy closure from children with anorectal malformation (n=8). The distributions of neuronal nitric oxide synthase (nNOS), choline acetyltransferase (ChAT), vasoactive intestinal peptide (VIP), and substance P (SP) were evaluated using immunofluorescence and confocal microscopy. Neurotransmitter quantification was with Western blot analysis. ChAT expression was high in aganglionic bowel and transition zone but reduced in ganglionic bowel in HSCR relative to controls. Conversely, nNOS expression was markedly reduced in aganglionic bowel but high in ganglionic bowel in HSCR relative to controls. VIP expression was similar in ganglionic HSCR and control colon. SP expression was similar in all tissue types. Imbalance of key excitatory and inhibitory neurotransmitters in the ganglionic bowel in HSCR may explain the basis of bowel dysmotility after an optimal pull-through operation in some patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Self-excitation of microwave oscillations in plasma-assisted slow-wave oscillators by an electron beam with a movable focus

    Science.gov (United States)

    Bliokh, Yu. P.; Nusinovich, G. S.; Shkvarunets, A. G.; Carmel, Y.

    2004-10-01

    Plasma-assisted slow-wave oscillators (pasotrons) operate without external magnetic fields, which makes these devices quite compact and lightweight. Beam focusing in pasotrons is provided by ions, which appear in the device due to the impact ionization of a neutral gas by beam electrons. Typically, the ionization time is on the order of the rise time of the beam current. This means that, during the rise of the current, beam focusing by ions becomes stronger. Correspondingly, a beam of electrons, which was initially diverging radially due to the self-electric field, starts to be focused by ions, and this focus moves towards the gun as the ion density increases. This feature makes the self-excitation of electromagnetic (em) oscillations in pasotrons quite different from practically all other microwave sources where em oscillations are excited by a stationary electron beam. The process of self-excitation of em oscillations has been studied both theoretically and experimentally. It is shown that in pasotrons, during the beam current rise the amount of current entering the interaction space and the beam coupling to the em field vary. As a result, the self-excitation can proceed faster than in conventional microwave sources with similar operating parameters such as the operating frequency, cavity quality-factor and the beam current and voltage.

  14. Small bowel endoluminal imaging (capsule and enteroscopy).

    Science.gov (United States)

    Murino, Alberto; Despott, Edward J

    2017-04-01

    Over the last 16 years, the disruptive technologies of small bowel capsule endoscopy and device-assisted enteroscopy have revolutionised endoluminal imaging and minimally invasive therapy of the small bowel. Further technological developments continue to expand their indications and use. This brief review highlights the state-of-the-art in this arena and aims to summarise the current and potential future role of these technologies in clinical practice.

  15. Use of Prebiotics for Inflammatory Bowel Disease

    OpenAIRE

    Szilagyi, Andrew

    2005-01-01

    The relevance of diet in both the pathogenesis and the therapy of inflammatory bowel disease is an evolving science. Disturbance of intestinal microflora (dysbiosis) is putatively a key element in the environmental component causing inflammatory bowel disease. Prebiotics are among the dietary components used in an attempt to counteract dysbiosis. Such predominantly carbohydrate dietary components exert effects on the luminal environment by physicochemical changes through pH alteration, by pro...

  16. Small bowel obstruction in children: usefulness of CT for diagnosis and localization

    International Nuclear Information System (INIS)

    Lee, Young Cheol; Kim, Young Tong; Bae, Won Kyung; Kim, Il Young

    2007-01-01

    To evaluate the usefulness of CT for the diagnosis of the cause and localization of small bowel obstruction. Out of a group of children who underwent a CT examination for a suspected small bowel obstruction, 19 patients with confirmed underlying disorders were identified and included in the study. Neonates and patients with duodenal obstruction were excluded from the study. The CT findings were analyzed for the location of obstruction site, abnormalities of the mesentery and mesenteric vessels, bowel wall thickening, closed loop obstruction, and strangulation. The obstruction site was divided into five parts. The preoperative CT diagnosis was compared with the final diagnosis. Causes of small bowel obstruction were intussusception (n = 6), appendiceal perforation (n = 4), transmesenteric internal hernia (n = 2), postoperative bands (n = 1), idiopathic multiple bands (n = 1), a foreign body (n = 1), a small bowel adenocarcinoma (n = 1), Meckel's diverticulitis (n = 1), tuberculous peritonitis (n = 1) and Salmonella enteritis with bowel perforation (n = 1). The CT findings showed mesenteric vascular prominence (n = 13), omental or mesenteric infiltration (n = 10), localized bowel wall thickening (n = 7) closed loops obstruction (n = 3) and strangulation (n = 1). The obstruction site was identified in all cases. The causes of obstruction could be diagnosed preoperatively in 14 cases, but a preoperative diagnosis was difficult in 5 cases. The causes of small bowel obstruction in children are variable, and CT is useful for evaluating the cause and localization of small bowel obstruction

  17. Differential Diagnosis between Benign and Malignant Bowel Lesions on Ultrasonogram and CT

    International Nuclear Information System (INIS)

    Suh, Chan Hae; Kim, Mi Young

    1996-01-01

    To evaluate the diagnostic criteria for differentiation between benign and malignant bowel wall lesions on ultrasonogram (US) and CT. We prospectively analyzed 55 bowel lesions on US and CT, including 29 cases of benign lesion and 26 cases of malignant lesion. The thickness and length of the lesions were measured and the bowel features were classified into four categories : a) obliteration of bowel wall layers, b) marginal irregularity, c)eccentric wall thickening, and d) heterogeneous perilesional fat changes. We analyzed the sensitivity, specificity, positive and negative predictive values of each criterion. The mean thickness of malignant bovel lesions was 1.77 / 1.84 cm on US/CT, and that of benign lesions was 0.71 / 0.80 cm on US/CT. There was statistically significant difference in thickness between benign and malignant lesions (P<.05). The statistical analysis of incremental study showed that the most sensitive and specific criteria for malignant lesions were more than 1.2cm in thickness and less than 5.0cm in length. Among feature criteria, bowel wall obliteration, irregular margin and eccentric contour were statistically and significantly different between benign and malignant lesions (P<.05). The most sensitive and specific feature criterion was the bowel wall obliteration. The most sensitive and specific criteria for differentiation between benign and malignant bowel lesions were thickness and obliteration of bowel wall layers. Particularly, US was useful for the detection of bowel wall layers

  18. Small bowel obstruction in children: usefulness of CT for diagnosis and localization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Cheol; Kim, Young Tong; Bae, Won Kyung; Kim, Il Young [Cheonan Hospital, Soonchunhyang University, Cheonan (Korea, Republic of)

    2007-12-15

    To evaluate the usefulness of CT for the diagnosis of the cause and localization of small bowel obstruction. Out of a group of children who underwent a CT examination for a suspected small bowel obstruction, 19 patients with confirmed underlying disorders were identified and included in the study. Neonates and patients with duodenal obstruction were excluded from the study. The CT findings were analyzed for the location of obstruction site, abnormalities of the mesentery and mesenteric vessels, bowel wall thickening, closed loop obstruction, and strangulation. The obstruction site was divided into five parts. The preoperative CT diagnosis was compared with the final diagnosis. Causes of small bowel obstruction were intussusception (n = 6), appendiceal perforation (n = 4), transmesenteric internal hernia (n = 2), postoperative bands (n = 1), idiopathic multiple bands (n = 1), a foreign body (n = 1), a small bowel adenocarcinoma (n = 1), Meckel's diverticulitis (n = 1), tuberculous peritonitis (n = 1) and Salmonella enteritis with bowel perforation (n = 1). The CT findings showed mesenteric vascular prominence (n = 13), omental or mesenteric infiltration (n = 10), localized bowel wall thickening (n = 7) closed loops obstruction (n = 3) and strangulation (n = 1). The obstruction site was identified in all cases. The causes of obstruction could be diagnosed preoperatively in 14 cases, but a preoperative diagnosis was difficult in 5 cases. The causes of small bowel obstruction in children are variable, and CT is useful for evaluating the cause and localization of small bowel obstruction.

  19. Small bowel ultrasound in patients with celiac disease

    Energy Technology Data Exchange (ETDEWEB)

    Bartusek, D. [Department of Radiology, Masaryk University hospital Brno (Czech Republic)], E-mail: dbartusek@fnbrno.cz; Valek, V. [Department of Radiology, Masaryk University hospital Brno (Czech Republic)], E-mail: v.valek@fnbrno.cz; Husty, J. [Department of Radiology, Masaryk University hospital Brno (Czech Republic)], E-mail: jhusty@fnbrno.cz; Uteseny, J. [Department of Pediatric Internal Medicine, Masaryk University hospital Brno (Czech Republic)], E-mail: juteseny@fnbrno.cz

    2007-08-15

    Objective: Celiac disease (CD) is a common, lifelong disease with small bowel malabsorption based on genetically conditioned gluten intolerance. The clinical manifestation could be very heterogeneous. The proof of celiac disease is now based mainly on clinical and laboratory (antibodies and enterobiopsy) signs, which are in some cases problematic and inconvenient. Materials and methods: In our study we have examined 250 patients with suspection or with proven celiac disease and we evaluated specific ultrasound small bowel changes in this group. In the next step, we chose 59 patients with laboratory proved celiac disease and we statistically compared ultrasound, other laboratory and clinical findings in different forms and stages of the disease. Results: Specific small bowel pathologies in patients with celiac disease (like changes of intestinal villi in different parts of small bowel, abnormal peristalsis and mesenterial lymphadenopathy) can be well visualized by ultrasound and in combination with clinical and laboratory signs ultrasound examination could have an important role in screening, determination of diagnosis and monitoring of patients with different forms of celiac disease.

  20. Small bowel ultrasound in patients with celiac disease

    International Nuclear Information System (INIS)

    Bartusek, D.; Valek, V.; Husty, J.; Uteseny, J.

    2007-01-01

    Objective: Celiac disease (CD) is a common, lifelong disease with small bowel malabsorption based on genetically conditioned gluten intolerance. The clinical manifestation could be very heterogeneous. The proof of celiac disease is now based mainly on clinical and laboratory (antibodies and enterobiopsy) signs, which are in some cases problematic and inconvenient. Materials and methods: In our study we have examined 250 patients with suspection or with proven celiac disease and we evaluated specific ultrasound small bowel changes in this group. In the next step, we chose 59 patients with laboratory proved celiac disease and we statistically compared ultrasound, other laboratory and clinical findings in different forms and stages of the disease. Results: Specific small bowel pathologies in patients with celiac disease (like changes of intestinal villi in different parts of small bowel, abnormal peristalsis and mesenterial lymphadenopathy) can be well visualized by ultrasound and in combination with clinical and laboratory signs ultrasound examination could have an important role in screening, determination of diagnosis and monitoring of patients with different forms of celiac disease

  1. Managing neonatal bowel obstruction: clinical perspectives

    Directory of Open Access Journals (Sweden)

    Desoky SM

    2018-02-01

    Full Text Available Sarah M Desoky,1 Ranjit I Kylat,2 Unni Udayasankar,1 Dorothy Gilbertson-Dahdal1 1Department of Medical Imaging, University of Arizona College of Medicine, Tucson, AZ, USA; 2Division of Neonatal-Perinatal Medicine, Department of Pediatrics, University of Arizona College of Medicine, Tucson, AZ, USA Abstract: Neonatal intestinal obstruction is a common surgical emergency and occurs in approximately 1 in 2,000 live births. The causes of obstruction are diverse with varied embryological origins, and some underlying etiologies are not yet well described. Some findings of neonatal bowel obstruction can be detected prenatally on ultrasound imaging. The obstruction is classified as “high” when the level of obstruction is proximal to the ileum, and “low” when the level of obstruction is at the ileum or colon. Early diagnosis of the type of intestinal obstruction and localization of the obstructive bowel segment guides timely and appropriate management of the underlying pathologic entity. Neonatal bowel obstructions are ideally managed at specialized centers with a large volume of neonatal surgery and dedicated pediatric surgical and anesthesia expertise. Although surgical intervention is necessary in most cases, initial management strategies often target underlying metabolic, cardiac, or respiratory abnormalities. Imaging plays a key role in early and accurate diagnosis of the abnormalities. When bowel obstruction is suspected clinically, initial imaging workup usually involves abdominal radiography, which may direct further evaluation with fluoroscopic examination such as upper gastrointestinal (UGI contrast study or contrast enema. This article provides a comprehensive review of clinical and radiological features of common and less common causes of intestinal obstruction in the neonatal age group, including esophageal atresia, enteric duplication cysts, gastric volvulus, congenital microgastria, hypertrophic pyloric stenosis, duodenal atresia

  2. Arteriovenous Malformation Detected by Small Bowel Endoscopy

    Directory of Open Access Journals (Sweden)

    Takaaki Fujii

    2014-10-01

    Full Text Available Gastrointestinal bleeding that originates in the small intestine is often difficult to diagnose. When successful diagnosis reveals a lesion that can be localized preoperatively, the laparoscopic approach is an appropriate and beneficial treatment modality for small bowel resection. A 69-year-old man presented with a 6-month history of gastrointestinal bleeding and symptomatic transfusion-dependent anemia. Upper and lower endoscopy were normal. Double-balloon endoscopy established the source of the bleeding as a 0.5-cm polypoid mass appearing as a submucosal tumor with redness and pulsation in the lower ileum, suggesting a vascular lesion. Laparoscopic small bowel resection was successful in removing the mass in the ileum. Histological evaluation of the mass revealed an arteriovenous malformation. Preoperative small bowel endoscopy can be useful for diagnosing the cause and localization of arteriovenous malformation in the small intestine.

  3. US features of transient small bowel intussusception in pediatric patients

    International Nuclear Information System (INIS)

    Kim, Ji Hye

    2004-01-01

    To describe the sonographic (US) and clinical features of spontaneously reduced small bowel intussusception, and to discuss the management options for small bowel intussusception based on US findings with clinical correlation. During a five years of period, 34 small bowel intussusceptions were diagnosed on US in 32 infants and children. The clinical presentations and imaging findings of the patients were reviewed. The clinical presentations included abdominal pain or irritability (n = 25), vomiting (n 5), diarrhea (n = 3), bloody stool (n = 1), and abdominal distension (n = 1), in combination or alone. US showed multi-layered round masses of small (mean, 1.5 ± 0.3 cm) diameters and with thin (mean, 3.5 ± 1 mm) outer rims along the course of the small bowel. The mean length was 1.8 ± 0.5 cm and peristalsis was seen on the video records. There were no visible lead points. The vascular flow signal appeared on color Doppler images in all 21 patients examined. Spontaneous reduction was confirmed by combinations of US (n = 28), small bowel series (n = 6), CT scan (n = 3), and surgical exploration (n 2). All patients discharged with improved condition. Typical US findings of the transient small bowel intussusception included 1) small size without wall swelling, 2) short segment, 3) preserved wall motion, and 4) absence of the lead point. Conservative management with US monitoring rather than an immediate operation is recommended for those patient with typical transient small bowel intussusceptions. Atypical US findings or clinical deterioration of the patient with persistent intussusception warrant surgical exploration

  4. Contouring and Constraining Bowel on a Full-Bladder Computed Tomography Scan May Not Reflect Treatment Bowel Position and Dose Certainty in Gynecologic External Beam Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yaparpalvi, Ravindra, E-mail: ryaparpa@montefiore.org; Mehta, Keyur J.; Bernstein, Michael B.; Kabarriti, Rafi; Hong, Linda X.; Garg, Madhur K.; Guha, Chandan; Kalnicki, Shalom; Tomé, Wolfgang A.

    2014-11-15

    Purpose: To evaluate, in a gynecologic cancer setting, changes in bowel position, dose-volume parameters, and biological indices that arise between full-bladder (FB) and empty-bladder (EB) treatment situations; and to evaluate, using cone beam computed tomography (CT), the validity of FB treatment presumption. Methods and Materials: Seventeen gynecologic cancer patients were retrospectively analyzed. Empty-bladder and FB CTs were obtained. Full-bladder CTs were used for planning and dose optimization. Patients were given FB instructions for treatment. For the study purpose, bowel was contoured on the EB CTs for all patients. Bowel position and volume changes between FB and EB states were determined. Full-bladder plans were applied on EB CTs for determining bowel dose-volume changes in EB state. Biological indices (generalized equivalent uniform dose and normal tissue complication probability) were calculated and compared between FB and EB. Weekly cone beam CT data were available in 6 patients to assess bladder volume at treatment. Results: Average (±SD) planned bladder volume was 299.7 ± 68.5 cm{sup 3}. Median bowel shift in the craniocaudal direction between FB and EB was 12.5 mm (range, 3-30 mm), and corresponding increase in exposed bowel volume was 151.3 cm{sup 3} (range, 74.3-251.4 cm{sup 3}). Absolute bowel volumes receiving 45 Gy were higher for EB compared with FB (mean 328.0 ± 174.8 vs 176.0 ± 87.5 cm{sup 3}; P=.0038). Bowel normal tissue complication probability increased 1.5× to 23.5× when FB planned treatments were applied in the EB state. For the study, the mean percentage value of relative bladder volume at treatment was 32%. Conclusions: Full-bladder planning does not necessarily translate into FB treatments, with a patient tendency toward EB. Given the uncertainty in daily control over bladder volume for treatment, we strongly recommend a “planning-at-risk volume bowel” (PRV{sub B}owel) concept to account for bowel motion

  5. Subharmonic edge waves on a large, shallow island

    Science.gov (United States)

    Foda, Mostafa A.

    1988-08-01

    Subharmonic resonance of edge waves by incident and reflected waves has been studied thus far for the case of a plane infinite beach. The analysis will be extended here to the case of a curved coastline, with a large radius of curvature and slowly varying beach slope in the longshore direction. It will be shown that the effects of such slow beach slope changes on a propagating edge wave are similar to the familiar shoaling effects on incident waves. The case of subharmonic edge wave generation on large shallow islands will be discussed in detail. The nonlinear analysis will show that within a certain range of island sizes, the generation mechanism can produce a stable standing edge wave around the island. For larger islands the solution disintegrates into two out-of-phase envelopes of opposite-going edge waves. For still larger islands, the generated progressive edge waves become unstable to sideband modulations.

  6. Systematic review: Complementary and alternative medicine in the irritable bowel syndrome.

    LENUS (Irish Health Repository)

    Hussain, Z

    2012-02-03

    BACKGROUND: Complementary and alternative medical therapies and practices are widely employed in the treatment of the irritable bowel syndrome. AIM: To review the usage of complementary and alternative medicine in the irritable bowel syndrome, and to assess critically the basis and evidence for its use. METHODS: A systematic review of complementary and alternative medical therapies and practices in the irritable bowel syndrome was performed based on literature obtained through a Medline search. RESULTS: A wide variety of complementary and alternative medical practices and therapies are commonly employed by irritable bowel syndrome patients both in conjunction with and in lieu of conventional therapies. As many of these therapies have not been subjected to controlled clinical trials, some, at least, of their efficacy may reflect the high-placebo response rate that is characteristic of irritable bowel syndrome. Of those that have been subjected to clinical trials most have involved small poor quality studies. There is, however, evidence to support efficacy for hypnotherapy, some forms of herbal therapy and certain probiotics in irritable bowel syndrome. CONCLUSIONS: Doctors caring for irritable bowel syndrome patients need to recognize the near ubiquity of complementary and alternative medical use among this population and the basis for its use. All complementary and alternative medicine is not the same and some, such as hypnotherapy, forms of herbal therapy, specific diets and probiotics, may well have efficacy in irritable bowel syndrome. Above all, we need more science and more controlled studies; the absence of truly randomized placebo-controlled trials for many of these therapies has limited meaningful progress in this area.

  7. Impact of slow-light enhancement on optical propagation in active semiconductor photonic crystal waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; de Lasson, Jakob Rosenkrantz; Gregersen, Niels

    2015-01-01

    We derive and validate a set of coupled Bloch wave equations for analyzing the reflection and transmission properties of active semiconductor photonic crystal waveguides. In such devices, slow-light propagation can be used to enhance the material gain per unit length, enabling, for example......, the realization of short optical amplifiers compatible with photonic integration. The coupled wave analysis is compared to numerical approaches based on the Fourier modal method and a frequency domain finite element technique. The presence of material gain leads to the build-up of a backscattered field, which...... is interpreted as distributed feedback effects or reflection at passive-active interfaces, depending on the approach taken. For very large material gain values, the band structure of the waveguide is perturbed, and deviations from the simple coupled Bloch wave model are found....

  8. Risk factors for bowel dysfunction after sphincter-preserving rectal cancer surgery: a prospective study using the Memorial Sloan Kettering Cancer Center bowel function instrument.

    Science.gov (United States)

    Ihn, Myong Hoon; Kang, Sung-Bum; Kim, Duck-Woo; Oh, Heung-Kwon; Lee, Soo Young; Hong, Sa Min

    2014-08-01

    Until recently, no studies have prospectively evaluated bowel function after sphincter-preserving surgery for rectal cancer with the use of a validated bowel function scoring system. The aim of this study was to investigate possible risk factors for altered bowel function after sphincter-preserving surgery. This was a prospective study. The study was conducted between January 2006 and May 2012 at the authors' institution. Patients who underwent sphincter-preserving rectal cancer surgery were recruited. Bowel function was assessed 1 day before (baseline) and at 1 year after sphincter-preserving surgery or temporary ileostomy takedown with the use of the Memorial Sloan Kettering Cancer Center questionnaire. Multivariable analysis was performed to identify the factors associated with altered bowel function after surgery. Overall, 266 patients were eligible for the analysis. The tumor was located in the upper, middle, and lower rectum in 68 (25.5%), 113 (42.5%), and 85 (32.0%) patients. Intersphincteric resection and temporary ileostomy were performed in 18 (6.8%) and 129 (48.5%) patients. The mean Memorial Sloan Kettering Cancer Center score was 64.5 ± 7.6 at 1 year after sphincter-preserving surgery or temporary ileostomy takedown. The Memorial Sloan Kettering Cancer Center score decreased in 163/266 patients (61.3%) between baseline and 1 year after surgery. Tumor location (p = 0.01), operative method (p = 0.03), anastomotic type (p = 0.01), and temporary ileostomy (p = 0.01) were associated with altered bowel function after sphincter-preserving surgery in univariate analyses. In multivariable analysis, only tumor location was independently associated with impaired bowel function after sphincter-preserving rectal cancer surgery. This study was limited by its nonrandomized design and the lack of measurement before preoperative chemoradiotherapy. We suggest that preoperative counseling should be implemented to inform patients of the risk of bowel dysfunction

  9. Magnetic resonance imaging of the small bowel in children with idiopathic inflammatory bowel disease: evaluation of disease activity

    International Nuclear Information System (INIS)

    Alexopoulou, Efthymia; Loggitsi, Dimitra; Economopoulos, Nikos; Papakonstantinou, Olympia; Kelekis, Nikolaos L.; Roma, Eleftheria; Panagiotou, Ioanna; Pahoula, Ioanna

    2009-01-01

    Examinations using ionizing radiation are frequently used in the evaluation of disease activity in children affected by idiopathic inflammatory bowel disease (IBD). To develop an MR imaging protocol without the need for fluoroscopic insertion of an enteral tube and to assess the disease activity in children with IBD. Included in the study were 37 children (22 girls and 15 boys; age range 7-15 years, mean 11.67 years) with IBD who underwent MR imaging of the small bowel. Of these 37 children, 32 had Crohn disease and 5 had indeterminate colitis. A water solution containing herbal fibres was administered orally or through a nasogastric tube. Patients were imaged on a 1.5-T MR scanner with T1-weighted and Τ2-weighted sequences followed by a dynamic study using 3-D T1-W images after intravenous administration of gadolinium. The percentage enhancement of the bowel wall was significantly increased in patients with abnormal C-reactive protein (CRP) values compared to patients with CRP values in the normal range (P<0.001). A relatively weak but significant correlation between percentage enhancement of the bowel wall and CRP values was noted during all phases of enhancement. This MR imaging protocol is a safe and well-tolerated method for evaluating disease activity and extraintestinal manifestations of IBD in children. (orig.)

  10. Magnetic resonance imaging of the small bowel in children with idiopathic inflammatory bowel disease: evaluation of disease activity

    Energy Technology Data Exchange (ETDEWEB)

    Alexopoulou, Efthymia; Loggitsi, Dimitra; Economopoulos, Nikos; Papakonstantinou, Olympia; Kelekis, Nikolaos L. [National and Kapodistrian University of Athens, General University Hospital, Second Department of Radiology, Athens (Greece); Roma, Eleftheria; Panagiotou, Ioanna; Pahoula, Ioanna [National and Kapodistrian University of Athens, Aghia Sofia Children' s Hospital, First Department of Paediatrics, Athens (Greece)

    2009-08-15

    Examinations using ionizing radiation are frequently used in the evaluation of disease activity in children affected by idiopathic inflammatory bowel disease (IBD). To develop an MR imaging protocol without the need for fluoroscopic insertion of an enteral tube and to assess the disease activity in children with IBD. Included in the study were 37 children (22 girls and 15 boys; age range 7-15 years, mean 11.67 years) with IBD who underwent MR imaging of the small bowel. Of these 37 children, 32 had Crohn disease and 5 had indeterminate colitis. A water solution containing herbal fibres was administered orally or through a nasogastric tube. Patients were imaged on a 1.5-T MR scanner with T1-weighted and {tau}2-weighted sequences followed by a dynamic study using 3-D T1-W images after intravenous administration of gadolinium. The percentage enhancement of the bowel wall was significantly increased in patients with abnormal C-reactive protein (CRP) values compared to patients with CRP values in the normal range (P<0.001). A relatively weak but significant correlation between percentage enhancement of the bowel wall and CRP values was noted during all phases of enhancement. This MR imaging protocol is a safe and well-tolerated method for evaluating disease activity and extraintestinal manifestations of IBD in children. (orig.)

  11. Helping Patients Cope with Inflammatory Bowel Disease.

    Science.gov (United States)

    1984-01-01

    these strategies can be effective as long as the strategy leads to 1) containment of guilt, fear, anxiety, and grief, 2) generation of hope , 3...patients with a sense of hope and a feeling that the disease can be coped with. The most difficult aspect of living with inflammatory bowel disease is...Recovery (mastectomy patients) and the Ostomy Association. They consist of people with Inflammatory Bowel Disease. Members support one another by sharing

  12. Portal venous air in an adult patient with obstructive small bowel volvulus

    NARCIS (Netherlands)

    Tan, ECTH; Jager, GJ; Bleeker, WA; van Goor, Harry

    2002-01-01

    Background. Diagnosis of small bowel volvulus is frequently delayed often resulting in bowel ischaemia and infarction and impairing clinical outcome. Instant and correct diagnosis and subsequent adequate surgery may improve the outcome. Methods: We describe a 19-year-old female with small bowel

  13. Impact of patient education on quality of bowel preparation in outpatient colonoscopies.

    Science.gov (United States)

    Modi, Chintan; Depasquale, Joseph R; Digiacomo, W Scott; Malinowski, Judith E; Engelhardt, Kristen; Shaikh, Sohail N; Kothari, Shivangi T; Kottam, Raghu; Shakov, Rada; Maksoud, Charbel; Baddoura, Walid J; Spira, Robert S

    2009-01-01

    High-quality bowel preparation is essential for successful outpatient colonoscopy. Currently, the rate of adequate bowel preparation for outpatient colonoscopy in the USA is low. Patients often fail to adhere to recommended preparation instructions. Limited literature exists on evaluating educational intervention as a means of improving the quality of bowel preparation prior to outpatient colonoscopy. Our objective was to determine the effect of an educational intervention on the quality of outpatient colonoscopy preparation. The secondary objective was to determine whether the quality of bowel preparation improves overall colonoscopy outcomes as measured by rate of polyp detection and caecal intubation time. A single-blinded, prospective, randomised, controlled trial was conducted in two inner-city gastroenterology clinics in the USA. One hundred and sixty-four subjects were enrolled and randomly assigned to one of two groups. The control group subjects received verbal and written instructions for colonoscopy. The intervention group subjects received the same instructions and were then asked to answer a questionnaire. The subjects' responses were reviewed and an additional explanation of the preparation process provided. An attending gastroenterologist determined the quality of each bowel preparation at the time of colonoscopy using the Universal Preparation Assessment Scale. The educational intervention had no impact on the overall quality of bowel preparation (P=0.12). However, the type of food (liquid vs solid) consumed during the 24 hours prior to the procedure (P=0.04) and the time since the last solid meal (P=0.03) did have an impact on preparation quality. Other significant factors included elapsed time to first bowel movement from the initiation of bowel preparation (P=0.05) and age younger than 55 (P=0.02). Adequate bowel preparation was associated with shorter total procedure (P=0.001) and caecal intubation (P=0.01) times. Our study failed to demonstrate

  14. Infantile Short Bowel Syndrome: short and long term evaluation

    NARCIS (Netherlands)

    J.F. Olieman (Joanne)

    2009-01-01

    textabstractInfantile short bowel syndrome is a condition which is characterized by malabsorption of nutrients, as a result of congenital intestinal shortening or massive small bowel resection. Survival rates have improved over the years, but morbidity remains high and clinical management of these

  15. Long-wave equivalent viscoelastic solids for porous rocks saturated by two-phase fluids

    Science.gov (United States)

    Santos, J. E.; Savioli, G. B.

    2018-04-01

    Seismic waves traveling across fluid-saturated poroelastic materials with mesoscopic-scale heterogeneities induce fluid flow and Biot's slow waves generating energy loss and velocity dispersion. Using Biot's equations of motion to model these type of heterogeneities would require extremely fine meshes. We propose a numerical upscaling procedure to determine the complex and frequency dependent P-wave and shear moduli of an effective viscoelastic medium long-wave equivalent to a poroelastic solid saturated by a two-phase fluid. The two-phase fluid is defined in terms of capillary pressure and relative permeability flow functions. The P-wave and shear effective moduli are determined using harmonic compressibility and shear experiments applied on representative samples of the bulk material. Each experiment is associated with a boundary value problem that is solved using the finite element method. Since a poroelastic solid saturated by a two-phase fluid supports the existence of two slow waves, this upscaling procedure allows to analyze their effect on the mesoscopic-loss mechanism in hydrocarbon reservoir formations. Numerical results show that a two-phase Biot medium model predicts higher attenuation than classic Biot models.

  16. Impact of mechanical bowel preparation in elective colorectal surgery: A meta-analysis.

    Science.gov (United States)

    Rollins, Katie E; Javanmard-Emamghissi, Hannah; Lobo, Dileep N

    2018-01-28

    To analyse the effect of mechanical bowel preparation vs no mechanical bowel preparation on outcome in patients undergoing elective colorectal surgery. Meta-analysis of randomised controlled trials and observational studies comparing adult patients receiving mechanical bowel preparation with those receiving no mechanical bowel preparation, subdivided into those receiving a single rectal enema and those who received no preparation at all prior to elective colorectal surgery. A total of 36 studies (23 randomised controlled trials and 13 observational studies) including 21568 patients undergoing elective colorectal surgery were included. When all studies were considered, mechanical bowel preparation was not associated with any significant difference in anastomotic leak rates (OR = 0.90, 95%CI: 0.74 to 1.10, P = 0.32), surgical site infection (OR = 0.99, 95%CI: 0.80 to 1.24, P = 0.96), intra-abdominal collection (OR = 0.86, 95%CI: 0.63 to 1.17, P = 0.34), mortality (OR = 0.85, 95%CI: 0.57 to 1.27, P = 0.43), reoperation (OR = 0.91, 95%CI: 0.75 to 1.12, P = 0.38) or hospital length of stay (overall mean difference 0.11 d, 95%CI: -0.51 to 0.73, P = 0.72), when compared with no mechanical bowel preparation, nor when evidence from just randomized controlled trials was analysed. A sub-analysis of mechanical bowel preparation vs absolutely no preparation or a single rectal enema similarly revealed no differences in clinical outcome measures. In the most comprehensive meta-analysis of mechanical bowel preparation in elective colorectal surgery to date, this study has suggested that the use of mechanical bowel preparation does not affect the incidence of postoperative complications when compared with no preparation. Hence, mechanical bowel preparation should not be administered routinely prior to elective colorectal surgery.

  17. Inflammatory bowel disease.

    Science.gov (United States)

    Gibson, Peter R; Iser, John

    2005-04-01

    Inflammatory bowel disease (IBD) is increasing in frequency in Australia. General practitioners play an important role in early diagnosis and in a multidisciplinary approach to managing such patients. Keeping abreast of evolving concepts, particularly in treatment, is challenging. This article aims to address key issues in diagnosis and management to better equip general practitioners for their role in multidisciplinary management of patients with IBD. Making the diagnosis can be difficult, but is facilitated by appropriate clinical suspicion and sensible judgment as to who undergoes diagnostic tests such as colonoscopy. Treatment of ulcerative colitis has changed little in recent years, except for our improved ability to deliver mesalazine to the large bowel via the recent availability of several oral and rectal preparations. Prevention of relapse using these is an important strategy in the majority of patients. Treatment of Crohn disease is changing due to more realistic concepts of the natural history of the disease and the development of new, powerful anti-inflammatory therapies. Attention to issues other than intestinal inflammation such as nutrition, education and counselling, remain important in achieving optimal management.

  18. Inflammatory bowel disease and colorectal cancer

    Directory of Open Access Journals (Sweden)

    Andreja Ocepek

    2006-12-01

    Full Text Available Background: Colorectal cancer is one of the most frequent cancers in developed countries and Slovenia, and the incidence is still rising. Groups of people with higher risk for colorectal cancer are well defined. Among them are patients with inflammatory bowel disease. The risk is highest in patients in whom whole large bowel is affected by inflammation, it rises after 8 to 10 years and increases with the duration of the disease. Precancerous lesion is a displastic, chronically inflammed mucosa and not an adenoma as in cases of sporadic colorectal carcinoma.Conclusions: Many studies suggest that the influence of genetic factors differs between sporadic and inflammatory bowel disease related colorectal cancer. Symptomatic patients at the time of diagnosis have a much worse prognosis. The goal of prevention programes is therefore discovering early precancerous lesions. Established screening protocols are based on relatively frequent colonoscopies which are inconvinient for the patient as well as the endoscopist. Use of specific genetic markers, mutations of candidate genes, as a screening method and a prognostic predictor could greatly lighten therapeutic decisions.

  19. Helicon wave coupling to a chiral-plasma column

    International Nuclear Information System (INIS)

    Torres-Silva, H.; Reggiani, N.; Sakanaka, P.H.

    1995-01-01

    Inductive helicon wave coupling to a chiro-plasma column is studied numerically. In our theoretical model, the RF current distribution of the chiro-plasma is taken into account using the constitutive relations of a chiral-plasma. Computational results based on the data of present-day helicon devices are show. In particular, we discuss the role of magnetic-field-aligned electron landau damping for the helicon wave absorption. In many a see, the numerical findings can be understood reasonably in terms of the wavenumber spectra of the helicon wave dispersion relation for slow and fast wave of a chiral-plasma. In general however, the full electromagnetic treatment is necessary in order to describe and to understand the inductive coupling in the helicon wave regime. (author). 9 refs., 1 fig

  20. Influence of viscoelastic property on laser-generated surface acoustic waves in coating-substrate systems

    International Nuclear Information System (INIS)

    Sun Hongxiang; Zhang Shuyi; Xu Baiqiang

    2011-01-01

    Taking account of the viscoelasticity of materials, the pulsed laser generation of surface acoustic waves in coating-substrate systems has been investigated quantitatively by using the finite element method. The displacement spectra of the surface acoustic waves have been calculated in frequency domain for different coating-substrate systems, in which the viscoelastic properties of the coatings and substrates are considered separately. Meanwhile, the temporal displacement waveforms have been obtained by applying inverse fast Fourier transforms. The numerical results of the normal surface displacements are presented for different configurations: a single plate, a slow coating on a fast substrate, and a fast coating on a slow substrate. The influences of the viscoelastic properties of the coating and the substrate on the attenuation of the surface acoustic waves have been studied. In addition, the influence of the coating thickness on the attenuation of the surface acoustic waves has been also investigated in detail.

  1. Interacting Turing-Hopf Instabilities Drive Symmetry-Breaking Transitions in a Mean-Field Model of the Cortex: A Mechanism for the Slow Oscillation

    Science.gov (United States)

    Steyn-Ross, Moira L.; Steyn-Ross, D. A.; Sleigh, J. W.

    2013-04-01

    Electrical recordings of brain activity during the transition from wake to anesthetic coma show temporal and spectral alterations that are correlated with gross changes in the underlying brain state. Entry into anesthetic unconsciousness is signposted by the emergence of large, slow oscillations of electrical activity (≲1Hz) similar to the slow waves observed in natural sleep. Here we present a two-dimensional mean-field model of the cortex in which slow spatiotemporal oscillations arise spontaneously through a Turing (spatial) symmetry-breaking bifurcation that is modulated by a Hopf (temporal) instability. In our model, populations of neurons are densely interlinked by chemical synapses, and by interneuronal gap junctions represented as an inhibitory diffusive coupling. To demonstrate cortical behavior over a wide range of distinct brain states, we explore model dynamics in the vicinity of a general-anesthetic-induced transition from “wake” to “coma.” In this region, the system is poised at a codimension-2 point where competing Turing and Hopf instabilities coexist. We model anesthesia as a moderate reduction in inhibitory diffusion, paired with an increase in inhibitory postsynaptic response, producing a coma state that is characterized by emergent low-frequency oscillations whose dynamics is chaotic in time and space. The effect of long-range axonal white-matter connectivity is probed with the inclusion of a single idealized point-to-point connection. We find that the additional excitation from the long-range connection can provoke seizurelike bursts of cortical activity when inhibitory diffusion is weak, but has little impact on an active cortex. Our proposed dynamic mechanism for the origin of anesthetic slow waves complements—and contrasts with—conventional explanations that require cyclic modulation of ion-channel conductances. We postulate that a similar bifurcation mechanism might underpin the slow waves of natural sleep and comment on the

  2. Interaction of slow pions with atomic nuclei

    International Nuclear Information System (INIS)

    Troitskij, M.A.; Tsybul'nikov, A.V.; Chekunaev, N.I.

    1984-01-01

    Interactions of slow pions with atomic nuclei near to pion condensation are investigated. From comparison of experimental data with the theoretical calculation results on the basis of precise microscopic approach not bound with the random phase approximation (RPA) nuclear matter fundamental parameters near a critical point can be found. Optical potential of slow pions in nuclei, πN-scattering amplitudes and lengths, π-atom level isotopic shift, phenomenon of single-nucleon pion absorption by nucleus, phenomenon of nuclear critical opalescence are considered. The results of πN-scattering lengths calculation, sup(40-44)Ca, sup(24-29)Mg, sup(16-18)O π-atom level shift are presented. It is shown that the presence of π-condensate in nuclei can explain the observed suppression of p-wave potential terms. The phenomenon of single-nucleon pion absorption by nucleus is one of direct experiments which permits to reveal the π-condensate. The nuclear opalescence phenomenon is manifested in increase of pion photoproduction reaction cross section for account of nucleus proximity to π-condensation as compared with the calculated in the Fermi-gas model. The suggested method for calculating precondensate phenomena operates the better, the nearer is the system to the condensation threshold whereas the RPA method in this region is inapplicable

  3. Electromagnetic Lead Screw for Potential Wave Energy Application

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Wu, Weimin

    2014-01-01

    This paper presents a new type electromagnetic lead screw (EMLS) intended for wave energy application. Similar to the mechanical lead screw, this electromagnetic version can transfer slow linear motion to high-rotational motion, offering gearing effects. Compared with the existing pure magnetic...

  4. Small Bowel Obstruction due to Intestinal Xanthomatosis

    Directory of Open Access Journals (Sweden)

    L. E. Barrera-Herrera

    2015-01-01

    Full Text Available Vast majority of bowel obstruction is due to postoperative adhesions, malignancy, intestinal inflammatory disease, and hernias; however, knowledge of other uncommon causes is critical to establish a prompt treatment and decrease mortality. Xanthomatosis is produced by accumulation of cholesterol-rich foamy macrophages. Intestinal xanthomatosis is an uncommon nonneoplastic lesion that may cause small bowel obstruction and several cases have been reported in the English literature as obstruction in the jejunum. We report a case of small intestinal xanthomatosis occurring in a 51-year-old female who presented with one day of copious vomiting and intermittent abdominal pain. Radiologic images revealed jejunal loop thickening and inflammatory changes suggestive of foreign body obstruction, diagnostic laparoscopy found two strictures at the jejunum, and a pathologic examination confirmed a segmental small bowel xanthomatosis. This case illustrates that obstruction even without predisposing factors such as hyperlipidemia or lymphoproliferative disorders.

  5. Extensive small bowel intramural haematoma secondary to warfarin.

    Science.gov (United States)

    Limmer, Alexandra M; Clement, Zackariah

    2017-03-01

    Intramural haematoma is a rare complication of oral anticoagulant therapy, occurring in  1 in 2500 patients treated with warfarin. This report describes a 71-year-old gentleman who presented with tachycardia, vomiting and abdominal distension on a background of anticoagulation for a metallic aortic valve. He was found to have a supratherapeutic international normalized ratio (INR) of 9.9 with an extensive small bowel intramural haematoma and secondary small bowel obstruction. He was successfully managed non-operatively with fluid resuscitation, INR reversal, bowel rest and nasogastric decompression. The patient's presentation was atypical with a lack of classic symptoms such as abdominal pain. This highlights the importance of considering intramural haematoma as a differential diagnosis for gastrointestinal symptoms in anticoagulated patients.

  6. CT features for the detection of bowel perforation sites by blunt abdominal trauma

    International Nuclear Information System (INIS)

    Yeon, Jae Woo; Kim, Mi Young; Suh, Chang Hae; Cho, Young Up

    1996-01-01

    We evaluated the CT criteria useful for the diagnosis of the site of bowel perforation in patients with this or mesenteric injury caused by blunt abdominal trauma. CT findings of 26 patients with blunt abdominal trauma were retrospectively analyzed by two observers who were unaware of operative findings, and the results of their analysis were compared with those findings. Twenty cases of bowel perforation found at the jejunum (8), ileum (9), and colon (3), and six cases of mesenteric injuries were confirmed by operation. We evaluated CT findings of 1) segmental bowel wall thickening, b) focal mesenteric fat infiltration, c) loculated fluid collection and d) extraluminal air adjacent to the bowel, and in addition analyzed the locations of ascites and free air, and the associated injuries of solid organs. The most common finding at the site of bowel perforation was segmental bowel wall thickening (17 cases), followed by focal mesenteric fat infiltration (12 cases), loculated fluid (12 cases) and extraluminal air ajacent to the bowel (9 cases). Segmental bowel wall thickening was present at 34 sites, and the perforations were confirmed at 17 of these(50%). Focal mesenteric fat infiltration was present at 19 sites;the perforations were proven at 12(63%). Loculated fluid collections were confirmed at 12/20 sites(60%), and extraluminal air adjacent to the bowel at 9/12(75%). The positive predictive value of criteria a, b, d, c) was 100%, and the positive predictive values of a, b, c) and a, d) were 60 and 67%, respectively. We observed ascites in 16 cases and intraperitoneal free air in 8 cases, the locations of ascites and free air did not, however, significantly correlate with the perforation sites. Extraluminal air adjacent to the bowel was the most specific criterion, and segmental bowel wall thickening was the most sensitive criterion. of all criteria, the finding 'a, b, c, d' most accurately predicted the site of bowel perforation

  7. Inflammatory bowel disease epidemiology

    DEFF Research Database (Denmark)

    Burisch, Johan; Munkholm, Pia

    2013-01-01

    The occurrence of inflammatory bowel disease (IBD) is increasing worldwide, yet the reasons remain unknown. New therapeutic approaches have been introduced in medical IBD therapy, but their impact on the natural history of IBD remains uncertain. This review will summarize the recent findings...

  8. Small Bowel Volvulus Induced by Mesenteric Lymphangioma in an Adult: a Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jin Hee; Lee, Su Lim; Ku, Young Mi; An, Chang Hyeok; Chang, Eun Deok [Uijeongbu St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu (Korea, Republic of)

    2009-06-15

    Mesenteric lymphangiomas are rare abdominal masses that are seldom associated with small bowel volvulus, and especially in adult patients. We report here on an unusual case of small bowel volvulus that was induced by a mesenteric lymphangioma in a 43-year-old man who suffered from repeated bouts of abdominal pain. At multidetector CT, we noticed whirling of the cystic mesenteric mass and the adjacent small bowel around the superior mesenteric artery. Small bowel volvulus induced by the rotation of the mesenteric lymphangioma was found on exploratory laparotomy. Lymphangioma should be considered as a rare cause of small bowel volvulus in adult patients.

  9. Shock and Rarefaction Waves in a Heterogeneous Mantle

    Science.gov (United States)

    Jordan, J.; Hesse, M. A.

    2012-12-01

    We explore the effect of heterogeneities on partial melting and melt migration during active upwelling in the Earth's mantle. We have constructed simple, explicit nonlinear models in one dimension to examine heterogeneity and its dynamic affects on porosity, temperature and the magnesium number in a partially molten, porous medium comprised of olivine. The composition of the melt and solid are defined by a closed, binary phase diagram for a simplified, two-component olivine system. The two-component solid solution is represented by a phase loop where concentrations 0 and 1 to correspond to fayalite and forsterite, respectively. For analysis, we examine an advective system with a Riemann initial condition. Chromatographic tools and theory have primarily been used to track large, rare earth elements as tracers. In our case, we employ these theoretical tools to highlight the importance of the magnesium number, enthalpy and overall heterogeneity in the dynamics of melt migration. We calculate the eigenvectors and eigenvalues in the concentration-enthalpy space in order to glean the characteristics of the waves emerging the Riemann step. Analysis on Riemann problems of this nature shows us that the composition-enthalpy waves can be represented by self-similar solutions. The eigenvalues of the composition-enthalpy system represent the characteristic wave propagation speeds of the compositions and enthalpy through the domain. Furthermore, the corresponding eigenvectors are the directions of variation, or ``pathways," in concentration-enthalpy space that the characteristic waves follow. In the two-component system, the Riemann problem yields two waves connected by an intermediate concentration-enthalpy state determined by the intersections of the integral curves of the eigenvectors emanating from both the initial and boundary states. The first wave, ``slow path," and second wave, ``fast path," follow the aformentioned pathways set by the eigenvectors. The slow path wave

  10. Crystal plastic earthquakes in dolostones: from slow to fast ruptures.

    Science.gov (United States)

    Passelegue, F. X.; Aubry, J.; Nicolas, A.; Fondriest, M.; Schubnel, A.; Di Toro, G.

    2017-12-01

    Dolostone is the most dominant lithology of the seismogenic upper crust around the Mediterranean Sea. Understanding the internal mechanisms controlling fault friction is crucial for understanding seismicity along active faults. Displacement in such fault zones is frequently highlighted by highly reflective (mirror-like) slip surfaces, created by thin films of nanogranular fault rock. Using saw-cut dolostone samples coming from natural fault zones, we conducted stick-slip experiments under triaxial loading conditions at 30, 60 and 90 MPa confining pressure and temperature ranging from 30 to 100 degrees C. At 30 and 65 degrees C, only slow rupture was observed and the experimental fault exhibits frictional behaviour, i.e. a dependence of normal stress on peak shear stress. At 65 degrees C, a strengthening behaviour is observed after the main rupture, leading to a succession of slow rupture. At 100 degrees C, the macroscopic behaviour of the fault becomes ductile, and no dependence of pressure on the peak shear stress is observed. In addition, the increase of the confining pressure up to 60 and 90 MPa allow the transition from slow to fast rupture, highlighted by the records of acoustic activity and by dynamic stress drop occurring in a few tens of microseconds. Using strain gages located along the fault surface and acoustic transducers, we were able to measure the rupture velocities during slow and fast rupture. Slow ruptures propagated around 0.1 m/s, in agreement with natural observations. Fast ruptures propagated up to supershear velocities, i.e. faster than the shear wave speed (>3500 m/s). A complete study of the microstructures was realized before and after ruptures. Slow ruptures lead to the production of mirror-like surface driven by the production of nanograins due to dislocation processes. Fast ruptures induce the production of amorphous material along the fault surface, which may come from decarbonation and melting processes. We demonstrate that the

  11. Preoperative Diagnosis of Adult Intussusception Caused by Small Bowel Lipoma

    Directory of Open Access Journals (Sweden)

    Hiroaki Shiba

    2009-11-01

    Full Text Available Adult intussusception is rare, accounting for only 5% of all intussusceptions, for which preoperative diagnosis is difficult. We herein report a preoperatively diagnosed case of adult intussusception caused by a small bowel lipoma. A 33-year-old man was admitted to our hospital with three weeks history of colicky epigastric pain. Computed tomography revealed thickening of the ileal wall suggestive of intussusception. Colonoscopy revealed an ileocolic intussusception. Barium enema for reduction of ileocolic intussusception demonstrated a small bowel tumor in the ileum 15 cm proximal to the ileocecal valve. The intussusception was reduced, and the patient underwent partial resection of the ileum encompassing the small bowel tumor. Histological findings confirmed the diagnosis of lipoma of the small bowel. The patient made a satisfactory recovery and remains well.

  12. Traveling waves in a free-electron laser with an electromagnetic wiggler

    International Nuclear Information System (INIS)

    Olumi, Mohsen; Maraghechi, B; Rouhani, M H

    2011-01-01

    The propagation of electromagnetic traveling wave in a free-electron laser (FEL) with an electromagnetic wiggler is investigated using the relativistic fluid-Maxwell formulation. By adapting the traveling-wave ansatz, three coupled, nonlinear ordinary differential equations are obtained describing the nonlinear propagation of the coupled wave. These equations may be used to study saturation in FELs. By linearizing the nonlinear equations dispersion relations for the traveling wave are obtained. Numerical solution of the small-signal traveling dispersion relation reveals the coupling of radiation to both slow and fast space-charge waves. It is shown that the traveling wave, which is not a normal mode in a laboratory frame, becomes a normal mode in terms of a transformed variable.

  13. Slow briefs: slow food....slow architecture

    OpenAIRE

    Crotch, Joanna

    2012-01-01

    We are moving too fast…fast lives, fast cars, fast food…..and fast architecture. We are caught up in a world that allows no time to stop and think; to appreciate and enjoy all the really important things in our lives. Recent responses to this seemingly unstoppable trend are the growing movements of Slow Food and Cittaslow. Both initiatives are, within their own realms, attempting to reverse speed, homogeny, expediency and globalisation, considering the values of regionality, patience, craft, ...

  14. Asian motility studies in irritable bowel syndrome.

    Science.gov (United States)

    Lee, Oh Young

    2010-04-01

    Altered motility remains one of the important pathophysiologic factors in patients with irritable bowel syndrome (IBS) who commonly complain of abdominal pain and stool changes such as diarrhea and constipation. The prevalence of IBS has increased among Asian populations these days. Gastrointestinal (GI) physiology may vary between Asian and Western populations because of differences in diets, socio-cultural backgrounds, and genetic factors. The characteristics and differences of GI dysmotility in Asian IBS patients were reviewed. MEDLINE search work was performed including following terms, 'IBS,' 'motility,' 'transit time,' 'esophageal motility,' 'gastric motility,' 'small intestinal motility,' 'colonic motility,' 'anorectal function,' and 'gallbladder motility' and over 100 articles were categorized under 'esophagus,' 'stomach,' 'small intestine,' 'colon,' 'anorectum,' 'gallbladder,' 'transit,' 'motor pattern,' and 'effect of stressors.' Delayed gastric emptying, slow tansit in constipation predominant IBS patients, rapid transit in diarrhea predominant IBS patients, accelerated motility responses to various stressors such as meals, mental stress, or corticotrophin releasing hormones, and altered rectal compliance and altered rectal accomodation were reported in many Asian studies regarding IBS. Many conflicting results were found among these studies and there are still controversies to conclude these as unique features of Asian IBS patients. Multinational and multicenter studies are needed to be performed vigorously in order to elaborate characteristics as well as differences of altered motililty in Asian patients with IBS.

  15. Targeted therapies for diarrhea-predominant irritable bowel syndrome

    OpenAIRE

    Olden, Kevin W

    2012-01-01

    Kevin W OldenDepartment of Medicine, St Joseph's Hospital and Medical Center, Phoenix, AZ, USAAbstract: Irritable bowel syndrome (IBS) causes gastrointestinal symptoms such as abdominal pain, bloating, and bowel pattern abnormalities, which compromise patients' daily functioning. Common therapies address one or two IBS symptoms, while others offer wider symptom control, presumably by targeting pathophysiologic mechanisms of IBS. The aim of this targeted literature review was t...

  16. Recurrent intestinal volvulus in midgut malrotation causing acute bowel obstruction: A case report.

    Science.gov (United States)

    Sheikh, Fayed; Balarajah, Vickna; Ayantunde, Abraham Abiodun

    2013-03-27

    Intestinal malrotation occurs when there is a disruption in the normal embryological development of the bowel. The majority of patients present with clinical features in childhood, though rarely a first presentation can take place in adulthood. Recurrent bowel obstruction in patients with previous abdominal operation for midgut malrotation is mostly due to adhesions but very few reported cases have been due to recurrent volvulus. We present the case of a 22-year-old gentleman who had laparotomy in childhood for small bowel volvulus and then presented with acute bowel obstruction. Preoperative computerised tomography scan showed small bowel obstruction and features in keeping with midgut malrotation. Emergency laparotomy findings confirmed midgut malrotation with absent appendix, abnormal location of caecum, ascending colon and small bowel. In addition, there were small bowel volvulus and a segment of terminal ileal stricture. Limited right hemicolectomy was performed with excellent postoperative recovery. This case is presented to illustrate a rare occurrence and raise an awareness of the possibility of dreadful recurrent volvulus even several years following an initial Ladd's procedure for midgut malrotation. Therefore, one will need to exercise a high index of suspicion and this becomes very crucial in order to ensure prompt surgical intervention and thereby preventing an attendant bowel ischaemia with its associated high fatality.

  17. Tc-99m sucralfate scanning for inflammatory bowel disease

    International Nuclear Information System (INIS)

    Lieberman, L.M.; Becker, S.; Mekhmandarov, S.; Steinmetz, A.

    1987-01-01

    The authors investigated 14 patients with idiopathic inflammatory bowel disease (IBD) by administering Tc-99m sucralfate (TcS) orally and imaging the abdomen 4 and 24 hours after dose. All patients had either barium radiographic studies or colonoscopy before the scan. The scan identified seven of nine patients who had radiologically demonstrated small-bowel lesions and four of five patients with colonic disease. The authors' preliminary experience suggests that TcS maybe a useful procedure to document location and extent of active disease. It provides information about both small and large bowel in one procedure, is noninvasive, easy to perform, and has low radiation absorbed dose

  18. Identification of waves by RF magnetic probes during lower hybrid wave injection experiments on the TST-2 spherical tokamak

    International Nuclear Information System (INIS)

    Shinya, Takahiro; Ejiri, Akira; Takase, Yuichi

    2014-01-01

    RF magnetic probes can be used to measure not only the wavevector, but also the polarization of waves in plasmas. A 5-channel RF magnetic probe (5ch-RFMP) was installed in the TST-2 spherical tokamak and the waves were studied in detail during lower hybrid wave injection experiments. From the polarization measurements, the poloidal RF magnetic field is found to be dominant. In addition to polarization, components of k perpendicular to the major radial direction were obtained from phase differences among the five channels. The radial wavenumber was obtained by scanning the radial position of the 5ch-RFMP on a shot by shot basis. The measured wavevector and polarization in the plasma edge region were consistent with those calculated from the wave equation for the slow wave branch. While the waves with small and large k ∥ were excited by the antenna, only the small k ∥ component was measured by the 5ch-RFMP; this suggests that the waves with larger k ∥ were absorbed by the plasma. (author)

  19. Change in functional bowel symptoms after prostatectomy: A case-control study

    Directory of Open Access Journals (Sweden)

    Peyman Adibi

    2011-01-01

    Conclusions: This is the first forward study regarding bowel symptom changes following prostatectomy. The main positive finding of this study is that open prostatectomy was followed by significant increase in diarrhea and bowel habit alternation associated with onset of abdominal pain. Specifically the change was found after open operation but not after TURP. Prostatectomy whether in form of open or transurethral may cause onset of abdominal discomfort and bowel habit change.

  20. Follow-up of patients with functional bowel symptoms treated with a low FODMAP diet

    DEFF Research Database (Denmark)

    Maagaard, Louise; Ankersen, Dorit Vedel; Callaerts-Vegh, Zsuzsanna

    2016-01-01

    AIM: To investigate patient-reported outcomes from, and adherence to, a low FODMAP diet among patients suffering from irritable bowel syndrome and inflammatory bowel disease. METHODS: Consecutive patients with irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD) and co-existing IBS ...... deviations. Wheat, dairy products, and onions were the foods most often not reintroduced by patients. CONCLUSION: These data suggest that a diet low in FODMAPs is an efficacious treatment solution in the management of functional bowel symptoms for IBS and IBD patients....