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Sample records for bowel slow wave

  1. Source modeling sleep slow waves

    OpenAIRE

    Murphy, M.; Riedner, B.A.; Huber, R.; Massimini, M; F. Ferrarelli; Tononi, G

    2009-01-01

    Slow waves are the most prominent electroencephalographic (EEG) feature of sleep. These waves arise from the synchronization of slow oscillations in the membrane potentials of millions of neurons. Scalp-level studies have indicated that slow waves are not instantaneous events, but rather they travel across the brain. Previous studies of EEG slow waves were limited by the poor spatial resolution of EEGs and by the difficulty of relating scalp potentials to the activity of the underlying cortex...

  2. 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.

  3. Human Gamma Oscillations during Slow Wave Sleep

    OpenAIRE

    Mario Valderrama; Benoît Crépon; Vicente Botella-Soler; Jacques Martinerie; Dominique Hasboun; Catalina Alvarado-Rojas; Michel Baulac; Claude Adam; Vincent Navarro; Michel Le Van Quyen

    2012-01-01

    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 r...

  4. Slow Wave Sleep and Long Duration Spaceflight

    Science.gov (United States)

    Whitmire, Alexandra; Orr, Martin; Arias, Diana; Rueger, Melanie; Johnston, Smith; Leveton, Lauren

    2012-01-01

    While ground research has clearly shown that preserving adequate quantities of sleep is essential for optimal health and performance, changes in the progression, order and /or duration of specific stages of sleep is also associated with deleterious outcomes. As seen in Figure 1, in healthy individuals, REM and Non-REM sleep alternate cyclically, with stages of Non-REM sleep structured chronologically. In the early parts of the night, for instance, Non-REM stages 3 and 4 (Slow Wave Sleep, or SWS) last longer while REM sleep spans shorter; as night progresses, the length of SWS is reduced as REM sleep lengthens. This process allows for SWS to establish precedence , with increases in SWS seen when recovering from sleep deprivation. SWS is indeed regarded as the most restorative portion of sleep. During SWS, physiological activities such as hormone secretion, muscle recovery, and immune responses are underway, while neurological processes required for long term learning and memory consolidation, also occur. The structure and duration of specific sleep stages may vary independent of total sleep duration, and changes in the structure and duration have been shown to be associated with deleterious outcomes. Individuals with narcolepsy enter sleep through REM as opposed to stage 1 of NREM. Disrupting slow wave sleep for several consecutive nights without reducing total sleep duration or sleep efficiency is associated with decreased pain threshold, increased discomfort, fatigue, and the inflammatory flare response in skin. Depression has been shown to be associated with a reduction of slow wave sleep and increased REM sleep. Given research that shows deleterious outcomes are associated with changes in sleep structure, it is essential to characterize and mitigate not only total sleep duration, but also changes in sleep stages.

  5. Involvement of cytokines in slow wave sleep

    OpenAIRE

    Krueger, James M.; Clinton, James M.; Winters, Bradley D.; Zielinski, Mark R.; Taishi, Ping; Jewett, Kathryn A.; Davis, Christopher J.

    2011-01-01

    Cytokines such as tumor necrosis factor alpha (TNFα) and interleukin-1 beta (IL1β) play a role in sleep regulation in health and disease. TNFα or IL1β injection enhances non-rapid eye movement sleep. Inhibition of TNFα or IL1β reduces spontaneous sleep. Mice lacking TNFα or IL1β receptors sleep less. In normal humans and in multiple disease states, plasma levels of TNFα covary with EEG slow wave activity (SWA) and sleep propensity. Many of the symptoms induced by sleep loss, for example, slee...

  6. Triggering sleep slow waves by transcranial magnetic stimulation

    OpenAIRE

    Massimini, Marcello; Ferrarelli, Fabio; Esser, Steve K.; Riedner, Brady A.; Huber, Reto; Murphy, Michael; Peterson, Michael J.; Tononi, Giulio

    2007-01-01

    During much of sleep, cortical neurons undergo near-synchronous slow oscillation cycles in membrane potential, which give rise to the largest spontaneous waves observed in the normal electroencephalogram (EEG). Slow oscillations underlie characteristic features of the sleep EEG, such as slow waves and spindles. Here we show that, in sleeping subjects, slow waves and spindles can be triggered noninvasively and reliably by transcranial magnetic stimulation (TMS). With appropriate stimulation pa...

  7. Superconducting niobium thin film slow-wave structures

    Science.gov (United States)

    Bautista, J. J.; Petty, S. M.; Allen, L. H.; Beasley, M. R.; Hammond, R. H.

    1983-01-01

    A superconducting comb structure as a slow-wave element in a traveling-wave maser will significantly improve maser noise temperature and gain by reducing the insertion loss. The results of the insertion loss measurements of superconducting niobium slow-wave structures subjected to maser operating conditions at X-Band frequencies are presented.

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

    OpenAIRE

    Michele Bellesi; Garcia-Molina, Gary N.

    2014-01-01

    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 ...

  9. Review of slow-wave structures

    Science.gov (United States)

    Wallett, Thomas M.; Qureshi, A. Haq

    1994-06-01

    The majority of recent theoretical and experimental reports published in the literature dealing with helical slow-wave structures focus on the dispersion characteristics and their effects due to the finite helix wire thickness and attenuation, dielectric loading, metal loading, and the introduction of plasma. In many papers, an effective dielectric constant is used to take into account helix wire dimensions and conductivity losses, while the propagation constant of the signal and the interaction impedance of the structure are found to depend on the surface resistivity of the helix. Also, various dielectric supporting rods are simulated by one or several uniform cylinders having an effective dielectric constant, while metal vane loading and plasma effects are incorporated in the effective dielectric constant. The papers dealing with coupled cavities and folded or loaded wave guides describe equivalent circuit models, efficiency enhancement, and the prediction of instabilities for these structures. Equivalent circuit models of various structures are found using computer software programs SUPERFISH and TOUCHSTONE. Efficiency enhancement in tubes is achieved through dynamic velocity and phase adjusted tapers using computer techniques. The stability threshold of unwanted antisymmetric and higher order modes is predicted using SOS and MAGIC codes and the dependence of higher order modes on beam conductance, section length, and effective Q of a cavity is shown.

  10. Review of Slow-Wave Structures

    Science.gov (United States)

    Wallett, Thomas M.; Qureshi, A. Haq

    1994-01-01

    The majority of recent theoretical and experimental reports published in the literature dealing with helical slow-wave structures focus on the dispersion characteristics and their effects due to the finite helix wire thickness and attenuation, dielectric loading, metal loading, and the introduction of plasma. In many papers, an effective dielectric constant is used to take into account helix wire dimensions and conductivity losses, while the propagation constant of the signal and the interaction impedance of the structure are found to depend on the surface resistivity of the helix. Also, various dielectric supporting rods are simulated by one or several uniform cylinders having an effective dielectric constant, while metal vane loading and plasma effects are incorporated in the effective dielectric constant. The papers dealing with coupled cavities and folded or loaded wave guides describe equivalent circuit models, efficiency enhancement, and the prediction of instabilities for these structures. Equivalent circuit models of various structures are found using computer software programs SUPERFISH and TOUCHSTONE. Efficiency enhancement in tubes is achieved through dynamic velocity and phase adjusted tapers using computer techniques. The stability threshold of unwanted antisymmetric and higher order modes is predicted using SOS and MAGIC codes and the dependence of higher order modes on beam conductance, section length, and effective Q of a cavity is shown.

  11. Damping of Slow Magnetoacoustic Waves in an Inhomogeneous Coronal Plasma

    Indian Academy of Sciences (India)

    Nagendra Kumar; Pradeep Kumar; Shiv Singh; Anil Kumar

    2008-03-01

    We study the propagation and dissipation of slow magnetoacoustic waves in an inhomogeneous viscous coronal loop plasma permeated by uniform magnetic field. Only viscosity and thermal conductivity are taken into account as dissipative processes in the coronal loop. The damping length of slow-mode waves exhibit varying behaviour depending upon the physical parameters of the loop in an active region AR8270 observed by TRACE. The wave energy flux associated with slow magnetoacoustic waves turns out to be of the order of 106 erg cm-2 s-1 which is high enough to replace the energy lost through optically thin coronal emission and the thermal conduction belowto the transition region. It is also found that only those slow-mode waves which have periods more than 240 s provide the required heating rate to balance the energy losses in the solar corona. Our calculated wave periods for slow-mode waves nearly match with the oscillation periods of loop observed by TRACE.

  12. 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

  13. Properties of slow oscillation during slow-wave sleep and anesthesia in cats

    OpenAIRE

    Chauvette, Sylvain; Crochet, Sylvain; Volgushev, Maxim; Timofeev, Igor

    2011-01-01

    Deep anesthesia is commonly used as a model of slow-wave sleep (SWS). Ketamine-xylazine anesthesia reproduces the main features of sleep slow oscillation: slow, large amplitude waves in field potential, which are generated by the alternation of hyperpolarized and depolarized states of cortical neurons. However, direct quantitative comparison of field potential and membrane potential fluctuations during natural sleep and anesthesia is lacking, so it remains unclear how well the properties of s...

  14. Sharp Slow Waves in the EEG.

    Science.gov (United States)

    Janati, A Bruce; AlGhasab, Naif Saad; Alshammari, Raed Ayed; saad AlGhassab, Abdulmohsen; Al-Aslami Yossef Fahad

    2016-06-01

    There exists a paucity of data in the EEG literature on characteristics of "atypical" interictal epileptiform discharges (IEDs), including sharp slow waves (SSWs). This article aims to address the clinical, neurophysiological, and neuropathological significance of SSW The EEGs of 920 patients at a tertiary-care facility were prospectively reviewed over a period of one year. Thirty-six patients had SSWs in their EEG. Of these, 6 patients were excluded because of inadequate clinical data. The clinical and neuroimaging data of the remaining 30 patients were then retrospectively collected and reviewed, and the findings were correlated. The data revealed that SSWs were rare and age-related EEG events occurring primarily in the first two decades of life. All patients with SSWs had documented epilepsy, presenting clinically with partial or generalized epilepsy. It is notable that one-third of the patients with SSWs had chronic or static central nervous system (CNS) pathology, particularly congenital CNS anomalies. Though more than one mechanism may be involved in the pathogenesis of SSWs, this research indicates that the most compelling theory is a deeply seated cortical generator giving rise to this EEG pattern. The presence of SSWs should alert clinicians to the presence of partial or generalized epilepsy or an underlying chronic or static CNS pathology, in particular congenital CNS anomalies, underscoring the significance of brain magnetic resonance imaging in the work-up of this population. PMID:27373055

  15. Excitation of lower-hybrid waves by a slow-wave structure

    International Nuclear Information System (INIS)

    The excitation of lower hybrid waves by a multiple ring slow wave structure (4 waves, lambda = 23 cm) in a magnetized plasma is discussed. Wavelengths measured parallel and perpendicular to the magnetic field were in agreement with the theoretical dispersion relation. The waves propagated in a packet defined by the axial length of the slow wave structure. (auth)

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

    Directory of Open Access Journals (Sweden)

    Michele Bellesi

    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.

  17. Excitation of surface plasma waves over corrugated slow-wave structure

    Indian Academy of Sciences (India)

    Ashim P Jain; Jetendra Parashar

    2005-08-01

    A microwave propagating along vacuum–dielectric–plasma interface excites surface plasma wave (SPW). A periodic slow-wave structure placed over dielectric slows down the SPW. The phase velocity of slow SPW is sensitive to height, periodicity, number of periods, thickness and the separation between dielectric and slow-wave structure. These slow SPW can couple the microwave energy to the plasma and can sustain the discharge. The efficiency of the power coupling is few per cent and is sensitive to separation between dielectric and slow-wave structure.

  18. 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. PMID:27126045

  19. Shock Formation of Slow Magnetosonic Waves in Coronal Plumes

    Science.gov (United States)

    Cuntz, Manfred; Suess, Steven T.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    We investigate the height of shock formation in coroner plumes for slow magnetosonic waves. The models take into account plume geometric spreading, heat conduction and radiative damping. The wave parameters as well as the spreading functions of the plumes and the base magnetic field strengths are given by empirical constraints mostly from Solar and Heliospheric Observatory/Ultraviolet Coronagraph Spectrometer (SOHO/UVCS). Our models show that shock formation occurs at low coronal heights, i.e., within 1.3 solar radius, depending on the model parameters. The shock formation is calculated using the well-established wave breaking condition given by the intersection of C+ characteristics in the space-time plane. Our models show that shock heating by slow magnetosonic waves is expected to be relevant at most heights in solar coronal plumes, although slow magnetosonic waves are most likely not a solely operating energy supply mechanism.

  20. Scattering resonance of elastic wave and low-frequency equivalent slow wave

    Science.gov (United States)

    Meng, X.; Liu, H.; Hu, T.; Yang, L.

    2015-12-01

    Transmitted wave occurs as fast p-wave and slow p-wave in certain conditions when seismic waves travel through inhomogeneous layers. Energy of slow p-waves is strongest at some frequency band, but rather weak at both high frequency band and low frequency band, called scattering resonance. For practical seismic exploration, the frequency of slow p-wave occurs is below 10Hz, which cannot be explained by Biot's theory which predicts existence of the slow p-wave at ultrasonic band in the porous media. The slow p-wave equation have been derived, but which only adapted to explaining slow p-wave in the ultrasonic band. Experimental observations exhibit that slow p-wave also exists in nonporous media but with enormous low-velocity interbeds. When vertical incidence, elastic wave is simplified as compressing wave, the generation of slow waves is independent on shear wave. In the case of flat interbed and gas bubble, Liu (2006) has studied the transmission of acoustic waves, and found that the slow waves below the 10Hz frequency band can be explained. In the case of general elastic anisotropy medium, the tiheoretical research on the generation of slow waves is insufficient. Aiming at this problem, this paper presents an exponential mapping method based on transmitted wave (Magnus 1954), which can successfully explain the generation of the slow wave transmission in that case. Using the prediction operator (Claerbout 1985) to represent the transmission wave, this can be derived as first order partial differential equation. Using expansions in the frequency domain and the wave number domain, we find that the solutions have different expressions in the case of weak scattering and strong scattering. Besides, the method of combining the prediction operator and the exponential map is needed to extend to the elastic wave equation. Using the equation (Frazer and Fryer 1984, 1987), we derive the exponential mapping solution for the prediction operator of the general elastic medium

  1. Properties of slow oscillation during slow-wave sleep and anesthesia in cats.

    Science.gov (United States)

    Chauvette, Sylvain; Crochet, Sylvain; Volgushev, Maxim; Timofeev, Igor

    2011-10-19

    Deep anesthesia is commonly used as a model of slow-wave sleep (SWS). Ketamine-xylazine anesthesia reproduces the main features of sleep slow oscillation: slow, large-amplitude waves in field potential, which are generated by the alternation of hyperpolarized and depolarized states of cortical neurons. However, direct quantitative comparison of field potential and membrane potential fluctuations during natural sleep and anesthesia is lacking, so it remains unclear how well the properties of sleep slow oscillation are reproduced by the ketamine-xylazine anesthesia model. Here, we used field potential and intracellular recordings in different cortical areas in the cat to directly compare properties of slow oscillation during natural sleep and ketamine-xylazine anesthesia. During SWS cortical activity showed higher power in the slow/delta (0.1-4 Hz) and spindle (8-14 Hz) frequency range, whereas under anesthesia the power in the gamma band (30-100 Hz) was higher. During anesthesia, slow waves were more rhythmic and more synchronous across the cortex. Intracellular recordings revealed that silent states were longer and the amplitude of membrane potential around transition between active and silent states was bigger under anesthesia. Slow waves were mostly uniform across cortical areas under anesthesia, but in SWS, they were most pronounced in associative and visual areas but smaller and less regular in somatosensory and motor cortices. We conclude that, although the main features of the slow oscillation in sleep and anesthesia appear similar, multiple cellular and network features are differently expressed during natural SWS compared with ketamine-xylazine anesthesia. PMID:22016533

  2. Spontaneous neural activity during human slow wave sleep

    OpenAIRE

    Dang-Vu, Thien Thanh; Schabus, Manuel; Desseilles, Martin; Albouy, Geneviève; Boly, Mélanie; Darsaud, Annabelle; Gais, Steffen; Rauchs, Géraldine; Sterpenich, Virginie; Vandewalle, Gilles; Carrier, Julie; Moonen, Gustave; Balteau, Evelyne; Degueldre, Christian; Luxen, André

    2008-01-01

    Slow wave sleep (SWS) is associated with spontaneous brain oscillations that are thought to participate in sleep homeostasis and to support the processing of information related to the experiences of the previous awake period. At the cellular level, during SWS, a slow oscillation (140 μV) and delta waves (75–140 μV) during SWS in 14 non-sleep-deprived normal human volunteers. Significant increases in activity were associated with these waves in several cortical areas, including the inferior f...

  3. Slow Drift-Oscillations of a Ship in Irregular Waves

    Directory of Open Access Journals (Sweden)

    Odd M. Faltinsen

    1980-10-01

    Full Text Available A procedure to calculate horizontal slow drift excitation forces on an infinitely long horizontal cylinder in irregular beam sea waves is presented. The hydrodynamic boundary-value problem is solved correctly to second order in wave amplitude. Results in the form of second order transfer functions are presented for different, two-dimensional shapes. It is concluded that Newman's approximative method is a practical way to calculate slow drift excitation forces on a ship in beam sea and it is suggested that it may be used in a more general case. Applications of the results for moored ships are discussed.

  4. 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

  5. Slow waves in locally resonant metamaterials line defect waveguides

    CERN Document Server

    Kaina, Nadège; Bourlier, Yoan; Fink, Mathias; Berthelot, Thomas; Lerosey, Geoffroy

    2016-01-01

    The ability of electromagnetic waves to interact with matter governs many fascinating effects involved in fundamental and applied, quantum and classical physics. It is necessary to enhance these otherwise naturally weak effects by increasing the probability of wave/matter interactions, either through field confinement or slowing down of waves. This is commonly achieved with structured materials such as photonic crystal waveguides or coupled resonator optical waveguides. Yet their minimum structural scale is limited to the order of the wavelength which not only forbids ultra-small confinement but also severely limits their performance for slowing down waves. Here we show that line defect waveguides in locally resonant metamaterials can outperform these proposals due to their deep subwavelength scale. We experimentally demonstrate our approach in the microwave domain using 3D printed resonant wire metamaterials, achieving group indices ng as high as 227 over relatively wide frequency bands. Those results corres...

  6. Surface waves in oversized G-band slow-wave structures with rectangular corrugations

    International Nuclear Information System (INIS)

    Surface waves in oversized G-band slow-wave structure with rectangularly corrugated wall are analyzed numerically. The inner corrugation generates cylindrical surface wave. The outer corrugation also generates transverse magnetic surface wave. The upper cut-offs of surface waves are controlled by corrugation amplitude. In excitation of the surface waves by an annular electron beam, the slow cyclotron interaction as well as the Cherenkov interaction occur due to there-dimensional beam perturbations. The slow cyclotron interaction merges with the Cherenkov interaction at lower magnetic field. The merged growth rate is enhanced by 13% as compared to the isolated Cherenkov growth rate. The surface waves on inner and outer corrugations can have different frequencies and can be excited selectively by adjusting the beam radius of the electron beam. (author)

  7. Slow magnetosonic waves and fast flows in active region loops

    CERN Document Server

    Ofman, Leon; Davila, Joseph M

    2012-01-01

    Recent EUV spectroscopic observations indicate that slow magnetosonic waves are present in active region (AR) loops. Some of the spectral data were also interpreted as evidence of fast (~100-300 km/s) quasi-periodic flows. We have performed three-dimensional magnetohydrodynamic (3D MHD) modeling of a bipolar AR that contains impulsively generated waves and flows in coronal loops. The model AR is initiated with a dipole magnetic field and gravitationally stratified density, with an upflow driven steadily or periodically in localized regions at the footpoints of magnetic loops. The resulting flows along the magnetic field lines of the AR produce higher density loops compared to the surrounding plasma by injection of material into the flux-tubes and the establishment of siphon flow. We find that the impulsive onset of flows with subsonic speeds result in the excitation of damped slow magnetosonic waves that propagate along the loops and coupled nonlinearly driven fast mode waves. The phase speed of the slow magn...

  8. Standing Slow MHD Waves in Radiatively Cooling Coronal Loops

    Indian Academy of Sciences (India)

    K. S. Al-Ghafri

    2015-06-01

    The standing slow magneto-acoustic oscillations in cooling coronal loops are investigated. There are two damping mechanisms which are considered to generate the standing acoustic modes in coronal magnetic loops, namely, thermal conduction and radiation. The background temperature is assumed to change temporally due to optically thin radiation. In particular, the background plasma is assumed to be radiatively cooling. The effects of cooling on longitudinal slow MHD modes is analytically evaluated by choosing a simple form of radiative function, that ensures the temperature evolution of the background plasma due to radiation, coincides with the observed cooling profile of coronal loops. The assumption of low-beta plasma leads to neglecting the magnetic field perturbation and, eventually, reduces the MHD equations to a 1D system modelling longitudinal MHD oscillations in a cooling coronal loop. The cooling is assumed to occur on a characteristic time scale, much larger than the oscillation period that subsequently enables using the WKB theory to study the properties of standing wave. The governing equation describing the time-dependent amplitude of waves is obtained and solved analytically. The analytically derived solutions are numerically evaluated to give further insight into the evolution of the standing acoustic waves. We find that the plasma cooling gives rise to a decrease in the amplitude of oscillations. In spite of the reduction in damping rate caused by rising the cooling, the damping scenario of slow standing MHD waves strongly increases in hot coronal loops.

  9. 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...... directly radiate energy from a vane-type interaction structure of a vacuum electron device. The parameters of the antenna are optimized while taking the technological constraints into account....

  10. Laminar wave train structure of collisionless magnetic slow shocks

    International Nuclear Information System (INIS)

    The laminar wave train structure of collisionless magnetic slow shocks is investigated using two fluid hydromagnetics with ion cyclotron radius dispersion. For shock strengths less than the maximally strong switch-off shock, in the shock leading edge dispersive steepening forms a magnetic field gradient, while in the downstream flow dispersive propagation forms a trailing wave train; dispersion scale lengths are the ion inertial length if beta is smaller than 1 and the ion cyclotron radius if beta is greater than 1. In the switch-off slow shock leading edge, dispersion only produced rotations of the magnetic field direction; the gradient of the magnetic field magnitude, and hence the shock steepening length, is determined solely by resistive diffusion. The switch-off shock structure consists of a long trailing of magnetic rotations which are gradually damped by resistivity. (auth)

  11. Acetazolamide for electrical status epilepticus in slow-wave sleep.

    Science.gov (United States)

    Fine, Anthony L; Wirrell, Elaine C; Wong-Kisiel, Lily C; Nickels, Katherine C

    2015-09-01

    Electrical status epilepticus in slow-wave sleep (ESES) is characterized by nearly continuous spike-wave discharges during non-rapid eye movement (REM) sleep. ESES is present in Landau-Kleffner syndrome (LKS) and continuous spike and wave in slow-wave sleep (CSWS). Sulthiame has demonstrated reduction in spike-wave index (SWI) in ESES, but is not available in the United States. Acetazolamide (AZM) is readily available and has similar pharmacologic properties. Our aims were to assess the effect of AZM on SWI and clinical response in children with LKS and CSWS. Children with LKS or CSWS treated with AZM at our institution were identified retrospectively. Pre- and posttherapy electroencephalography (EEG) studies were evaluated for SWI. Parental and teacher report of clinical improvement was recorded. Six children met criteria for inclusion. Three children (50%) demonstrated complete resolution or SWI <5% after AZM. All children had improvement in clinical seizures and subjective improvement in communication skills and school performance. Five of six children had subjective improvement in hyperactivity and attention. AZM is a potentially effective therapy for children with LKS and CSWS. This study lends to the knowledge of potential therapies that can be used for these disorders, which can be challenging for families and providers. PMID:26230617

  12. Large-Scale Cortical Dynamics of Sleep Slow Waves

    OpenAIRE

    Botella-Soler, Vicente; Valderrama, Mario; Crépon, Benoît; Navarro, Vincent; Le Van Quyen, Michel

    2012-01-01

    Slow waves constitute the main signature of sleep in the electroencephalogram (EEG). They reflect alternating periods of neuronal hyperpolarization and depolarization in cortical networks. While recent findings have demonstrated their functional role in shaping and strengthening neuronal networks, a large-scale characterization of these two processes remains elusive in the human brain. In this study, by using simultaneous scalp EEG and intracranial recordings in 10 epileptic subjects, we exam...

  13. Band formation in coupled-resonator slow-wave structures.

    Science.gov (United States)

    Möller, Björn M; Woggon, Ulrike; Artemyev, Mikhail V

    2007-12-10

    Sequences of coupled-resonator optical waveguides (CROWs) have been examined as slow-wave structures. The formation of photonic bands in finite systems is studied in the frame of a coupled oscillator model. Several types of resonator size tuning in the system are evaluated in a systematical manner. We show that aperiodicities in sequences of coupled microspheres provide an additional degree of freedom for the design of photonic bands. PMID:19551030

  14. Slow-wave resonance in periodic stacks of anisotropic layers

    International Nuclear Information System (INIS)

    We consider a Fabry-Perot resonance (a transmission band edge resonance) in periodic layered structures involving birefringent layers. In a previous publication [Phys. Rev. E 72, 036619 (2005)] we have shown that the presence of birefringent layers with misaligned in-plane anisotropy can dramatically enhance the performance of the photonic-crystal resonator. It allows us to reduce its size by an order of magnitude without compromising on its performance. The key characteristic of the enhanced slow-wave resonator is that the Bloch dispersion relation ω(k) of the periodic structure displays a degenerate photonic band edge, in the vicinity of which the dispersion curve can be approximated as Δω∼(Δk)4, rather than Δω∼(Δk)2. Such a situation can be realized in specially arranged stacks of misaligned anisotropic layers. On the down side, the presence of birefringent layers results in the slow-wave resonance being coupled only with one (elliptic) polarization component of the incident wave, while the other polarization component is reflected back to space. In this paper we show how a small modification of the periodic layered array can solve the above fundamental problem and provide a perfect impedance match regardless of the incident wave polarization, while preserving the giant slow-wave resonance characteristic of a degenerate photonic band edge. Both features are of critical importance for many practical applications, such as the enhancement of various light-matter interactions, light amplification and lasing, optical and microwave filters, antennas, etc

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

    Science.gov (United States)

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

    2015-11-01

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

  16. Plastic-Flow Waves ("Slow-Waves") and Seismic Activity in Central-Eastern Asia

    Institute of Scientific and Technical Information of China (English)

    Wang Shengzu; Zhang Zongchun

    2005-01-01

    The results inferred from experiments with analogue models carried out previously have shown that two types of plastic-flow waves, "fast-waves" and "slow-waves", are induced in the lower lithosphere (including the lower crust and lithospheric mantle ) under driving at plate boundaries and both of them are viscous gravity waves formed by the superposition of major and subsidiary waves. The major waves are similar to solitary waves and the subsidiary waves are traveling waves. The plastic-flow waves in the lower lithosphere control seismic activities in the overlying seismogenic layer and result in the distribution of earthquakes along the wavecrest belts. "Fast-waves" propagated with velocities of orders of magnitude of 100 ~ 102km/a have been verified by wave-controlled earthquake migration, showing the "decade waves" and "century waves" with the average periods of 10.8 and 93.4 a, respectively, which originate from the Himalayan driving boundary. According to the recognition of the patterns of the beltlike distribution of strong earthquakes with Ms ≥ 7.0, it is indicated further in this paper that the "slow-waves" with velocities of orders of magnitude of 100 ~ 101 m/a also originated under compression from the Himalayan driving boundary. Strong earthquakes with Ms ≥ 7.0 are controlled mainly by subsidiary waves, because the major waves with a duration of up to 106 a for each disturbance cannot result in the accmnulation of enough energy for strong earthquakes due to the relaxation of the upper crust. The subsidiary waves propagate with an average wave length of 445 km, velocities of 0.81~2.80 m/a and periods of 0.16 ~ 0.55 Ma. The wavegenerating time at the Himalayan driving boundary is about 1.34 ~ 4.59 Ma before present for the "slow-waves", corresponding to the stage from the Mid Pliocene to the Mid EarlyPleistocene and being identical with one of the major tectonic episodes of the Himalayan tectonic movement. It is shown from the recognition of

  17. Ion-implanted GaAs slow wave monolithic structure

    International Nuclear Information System (INIS)

    The use of MeV ion-implantation for realization of a GaAs monolithically compatible device is demonstrated. Ion implants up to 6 MeV in energy are used employing Si and S atoms. The fabricated device is an electromagnetic slow wave microstrip-like structure designed for performance into the millimeter wave regime. Phase shift theta and insertion loss L measurements are performed for frequencies 2-18 GHz at room temperature. Comparison of the experimental ion-implanted device results to epitaxial device results indicates comparable electrical performance, with no more than a 30% reduction in theta but with an improvement in loss behavior, namely a L reduction up to 40%. These theta and L differences between the ion-implanted and epitaxial devices are attributed to differences in doping profiles. Theoretical modelling of theta characteristics produces agreement with experimental data to within a few percent. (author)

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

    OpenAIRE

    D Alistair Steyn-Ross

    2014-01-01

    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...

  19. EEG slow-wave coherence changes in propofol-induced general anesthesia: experiment and theory

    OpenAIRE

    Wang, Kaier; Steyn-Ross, Moira L.; Steyn-Ross, D. A.; Wilson, Marcus T.; Sleigh, Jamie W

    2014-01-01

    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 b...

  20. Characteristics of Short-wavelength Oblique Alfven and Slow waves

    CERN Document Server

    Zhao, J S; Yu, M Y; Lu, J Y; Wu, D J

    2014-01-01

    Linear properties of kinetic Alfv\\'en waves (KAWs) and kinetic slow waves (KSWs) are studied in the framework of two-fluid magnetohydrodynamics. We obtain the wave dispersion relations that are valid in a wide range of the wave frequency {\\omega} and plasma-to-magnetic pressure ratio {\\beta}. The KAW frequency can reach and exceed the ion cyclotron frequency at ion kinetic scales, whereas the KSW frequency remains sub-cyclotron. At {\\beta}\\sim1, the plasma and magnetic pressure perturbations of both modes are in anti-phase, so that there is nearly no total pressure perturbations. However, these modes exhibit several different properties. At high {\\beta}, the electric field polarization of KAW and KSW is opposite at the ion gyroradius scale, where KAWs are polarized in sense of electron gyration (right-hand polarized) and KSWs are left-hand polarized. The magnetic helicity {\\sigma}\\sim1 for KAWs and {\\sigma}\\sim-1 for KSWs, and the ion Alfv\\'en ratio R_{Ai}\\ll 1 for KAWs and R_{Ai}\\gg 1 for KSWs. We also found...

  1. Comparing the Robustness of High-Frequency Traveling-Wave Tube Slow-Wave Circuits

    Science.gov (United States)

    Chevalier, Christine T.; Wilson, Jeffrey D.; Kory, Carol L.

    2007-01-01

    A three-dimensional electromagnetic field simulation software package was used to compute the cold-test parameters, phase velocity, on-axis interaction impedance, and attenuation, for several high-frequency traveling-wave tube slow-wave circuit geometries. This research effort determined the effects of variations in circuit dimensions on cold-test performance. The parameter variations were based on the tolerances of conventional micromachining techniques.

  2. Source distribution of neuromagnetic slow-wave activity in schizophrenic patients : effects of activation

    OpenAIRE

    Fehr, Thorsten; Kissler, Johanna; Wienbruch, Christian; Moratti, Stephan; Elbert, Thomas; Watzl, Hans; Rockstroh, Brigitte

    2003-01-01

    When slow waves in the EEG delta and theta frequency range appear in the waking state, they may indicate pathological conditions including psychopathology. The generators of focal slow waves can be mapped using magnetic source imaging. The resulting brain maps may possibly characterize dysfunctional brain areas. The present study examined the stability of the density and distribution of MEG slow waves during three conditions-rest, mental arithmetic and imagery-in 30 schizophrenic patients and...

  3. Source distribution of neuromagnetic slow wave activity in schizophrenic and depressive patients

    OpenAIRE

    Wienbruch, Christian; Moratti, Stephan; Elbert, Thomas; Vogel, Ulrike; Fehr, Thorsten; Kissler, Johanna; Schiller, August; Rockstroh, Brigitte

    2003-01-01

    Objective: Focal slow waves in the delta and theta frequency range frequently appear in psychopathological conditions. Due to their focal nature they can be localized by dipole modeling. We previously reported regional clustering of slow waves in temporal and parietal cortex of schizophrenic patients whereas such activity is largely absent in normals. Here we examine, to what extent distribution of slow wave generators differentiates schizophrenic from depressive syndromes. Methods: The regio...

  4. Slow Magneto-acoustic Waves Observed above Quiet-Sun Region in a Dark Cavity

    CERN Document Server

    Liu, Jiajia; Wang, Yuming; Liu, Rui; Wang, Bin; Liao, Chijian; Shen, Chenglong; Zheng, Huinan; Miao, Bin; Su, Zhenpeng; Wang, S

    2012-01-01

    Waves play a crucial role in diagnosing the plasma properties of various structures in the solar corona and coronal heating. Slow magneto-acoustic (MA) waves are one of the important magnetohydrodynamic waves. In past decades, numerous slow MA waves were detected above the active regions and coronal holes, but 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 the 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 the phase speed, compression ratio, kinetic energy density, etc., 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).

  5. A 0.14 THz relativistic coaxial overmoded surface wave oscillator with metamaterial slow wave structure

    International Nuclear Information System (INIS)

    This paper presents a new kind of device for generating the high power terahertz wave by using a coaxial overmoded surface wave oscillator with metamaterial slow wave structure (SWS). A metallic metamaterial SWS is used to avoid the damage of the device driven by a high-voltage electron beam pulse. The overmoded structure is adopted to make it much easy to fabricate and assemble the whole device. The coaxial structure is used to suppress the mode competition in the overmoded device. Parameters of an electron beam and geometric structure are provided. Particle-in-cell simulation results show that the high power terahertz wave at the frequency of 0.14 THz is generated with the output power 255 MW and conversion efficiency about 21.3%

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

    International Nuclear Information System (INIS)

    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

  7. 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.

  8. Antidepressant Effects of Selective Slow Wave Sleep Deprivation in Major Depression: A High-Density EEG Investigation

    OpenAIRE

    Landsness, Eric C.; Goldstein, Michael R; Peterson, Michael J.; Tononi, Giulio; Benca, Ruth M

    2011-01-01

    Sleep deprivation can acutely reverse depressive symptoms in some patients with major depression. Because abnormalities in slow wave sleep are one of the most consistent biological markers of depression, it is plausible that the antidepressant effects of sleep deprivation are due to the effects on slow wave homeostasis. This study tested the prediction that selectively reducing slow waves during sleep (slow wave deprivation; SWD), without disrupting total sleep time, will lead to an acute red...

  9. Experimental and Automated Analysis Techniques for High-resolution Electrical Mapping of Small Intestine Slow Wave Activity

    OpenAIRE

    Angeli, Timothy R.; O'Grady, Gregory; Paskaranandavadivel, Niranchan; Jonathan C Erickson; Du, Peng; Pullan, Andrew J; Bissett, Ian P.; Cheng, Leo K

    2013-01-01

    Background/Aims Small intestine motility is governed by an electrical slow wave activity, and abnormal slow wave events have been associated with intestinal dysmotility. High-resolution (HR) techniques are necessary to analyze slow wave propagation, but progress has been limited by few available electrode options and laborious manual analysis. This study presents novel methods for in vivo HR mapping of small intestine slow wave activity. Methods Recordings were obtained from along the porcine...

  10. Slow-Mode MHD Wave Penetration into a Coronal Null Point due to the Mode Transmission

    Science.gov (United States)

    Afanasyev, Andrey N.; Uralov, Arkadiy M.

    2016-05-01

    Recent observations of magnetohydrodynamic oscillations and waves in solar active regions revealed their close link to quasi-periodic pulsations in flaring light curves. The nature of that link has not yet been understood in detail. In our analytical modelling we investigate propagation of slow magnetoacoustic waves in a solar active region, taking into account wave refraction and transmission of the slow magnetoacoustic mode into the fast one. The wave propagation is analysed in the geometrical acoustics approximation. Special attention is paid to the penetration of waves in the vicinity of a magnetic null point. The modelling has shown that the interaction of slow magnetoacoustic waves with the magnetic reconnection site is possible due to the mode transmission at the equipartition level where the sound speed is equal to the Alfvén speed. The efficiency of the transmission is also calculated.

  11. Microfabrication of diamond-based slow-wave circuits for mm-wave and THz vacuum electronic sources

    International Nuclear Information System (INIS)

    Planar and helical slow-wave circuits for THz radiation sources have been made using novel microfabrication and assembly methods. A biplanar slow-wave circuit for a 650 GHz backward wave oscillator (BWO) was fabricated through the growth of diamond into high aspect ratio silicon molds and the selective metallization of the tops and sidewalls of 90 µm tall diamond features using lithographically created shadow masks. Helical slow-wave circuits for a 650 GHz BWO and a 95 GHz traveling wave tube were created through the patterning of trenches in thin film diamond, electroplating of gold half-helices, and high accuracy bonding of helix halves. The development of new techniques for the microfabrication of vacuum electronic components will help to facilitate compact and high-power sources for terahertz range radiation

  12. Microfabrication of diamond-based slow-wave circuits for mm-wave and THz vacuum electronic sources

    Science.gov (United States)

    Lueck, M. R.; Malta, D. M.; Gilchrist, K. H.; Kory, C. L.; Mearini, G. T.; Dayton, J. A.

    2011-06-01

    Planar and helical slow-wave circuits for THz radiation sources have been made using novel microfabrication and assembly methods. A biplanar slow-wave circuit for a 650 GHz backward wave oscillator (BWO) was fabricated through the growth of diamond into high aspect ratio silicon molds and the selective metallization of the tops and sidewalls of 90 µm tall diamond features using lithographically created shadow masks. Helical slow-wave circuits for a 650 GHz BWO and a 95 GHz traveling wave tube were created through the patterning of trenches in thin film diamond, electroplating of gold half-helices, and high accuracy bonding of helix halves. The development of new techniques for the microfabrication of vacuum electronic components will help to facilitate compact and high-power sources for terahertz range radiation.

  13. Stick-slip at soft adhesive interfaces mediated by slow frictional waves.

    Science.gov (United States)

    Viswanathan, Koushik; Sundaram, Narayan K; Chandrasekar, Srinivasan

    2016-06-28

    Stick-slip is a friction instability that governs diverse phenomena from squealing automobile brakes to earthquakes. At soft adhesive interfaces, this instability has long been attributed to Schallamach waves, which are a type of slow frictional wave. We use a contact configuration capable of isolating single wave events, coupled with high speed in situ imaging, to demonstrate the existence of two new stick-slip modes. It is shown that these modes also correspond to the passage of slow waves-separation pulse and slip pulse-with distinct nucleation and propagation characteristics. The slip pulse, characterized by a sharp stress front, propagates in the same direction as the Schallamach wave. In contrast, the separation pulse, involving local interface detachment and resembling a tensile neck, travels in exactly the opposite direction. A change in the stick-slip mode from the separation to the slip pulse is effected simply by increasing the normal force. Taken together, the three waves constitute all possible stick-slip modes in low-velocity sliding. The detailed observations enable us to present a phase diagram delineating the domains of occurrence of these waves. We suggest a direct analogy between the observed slow frictional waves and well known muscular locomotory waves in soft bodied organisms. Our work answers basic questions about adhesive mechanisms of frictional instabilities in natural and engineered systems, with broader implications for slow surface wave phenomena. PMID:27118236

  14. Propagation of Long-Wavelength Nonlinear Slow Sausage Waves in Stratified Magnetic Flux Tubes

    Science.gov (United States)

    Barbulescu, M.; Erdélyi, R.

    2016-05-01

    The propagation of nonlinear, long-wavelength, slow sausage waves in an expanding magnetic flux tube, embedded in a non-magnetic stratified environment, is discussed. The governing equation for surface waves, which is akin to the Leibovich-Roberts equation, is derived using the method of multiple scales. The solitary wave solution of the equation is obtained numerically. The results obtained are illustrative of a solitary wave whose properties are highly dependent on the degree of stratification.

  15. 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.

  16. 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.

  17. EEG slow-wave coherence changes in propofol-induced general anesthesia: experiment and theory.

    Science.gov (United States)

    Wang, Kaier; Steyn-Ross, Moira L; Steyn-Ross, D A; Wilson, Marcus T; Sleigh, Jamie W

    2014-01-01

    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. (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-vs.-unconscious coherence changes occurring at the frontal cortex. PMID:25400558

  18. Bistability of Slow and Fast Traveling Waves in Fluid Mixtures

    OpenAIRE

    Hollinger, St.; Buechel, P.; Luecke, M.

    1997-01-01

    The appearence of a new type of fast nonlinear traveling wave states in binary fluid convection with increasing Soret effect is elucidated and the parameter range of their bistability with the common slower ones is evaluated numerically. The bifurcation behavior and the significantly different spatiotemporal properties of the different wave states - e.g. frequency, flow structure, and concentration distribution - are determined and related to each other and to a convenient measure of their no...

  19. 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

  20. Theory for resonant ion acceleration by nonlinear magnetosonic fast and slow waves in finite beta plasmas

    International Nuclear Information System (INIS)

    A Korteweg--de Vries equation that is applicable to both the nonlinear magnetosonic fast and slow waves is derived from a two-fluid model with finite ion and electron pressures. As in the cold plasma theory, the fast wave has a critical angle theta/sub c/. For propagation angles greater than theta/sub c/ (quasiperpendicular propagation), the fast wave has a positive soliton, whereas for angles smaller than theta/sub c/, it has a negative soliton. Finite β effects decrease the value of theta/sub c/. The slow wave has a positive soliton for all angles of propagation. The magnitude of resonant ion acceleration (the v/sub p/ x B acceleration) by the nonlinear fast and slow waves is evaluated. In the fast wave, the electron pressure makes the acceleration stronger for all propagation angles. The decrease in theta/sub c/ resulting from finite β effects results in broadening of the region of strong acceleration. It is also found that fairly strong ion acceleration can occur in the nonlinear slow wave in high β plasmas. The possibility of unlimited acceleration of ions by quasiperpendicular magnetosonic fast waves is discussed

  1. Slow thermal waves in impurity seeded radiative plasmas

    International Nuclear Information System (INIS)

    Linear and nonlinear wave propagation in optically thin, impurity seeded radiative plasmas is studied in slab geometry. Taking into account the thermal force that acts on impurity ions leads to a new type of slightly damped or slightly unstable subsonic waves that propagate within limited ranges of temperature. The one-dimensional nonlinear equation reduces to that of a classical particle in a forced external field with nonlinear friction. It is shown that the slightly unstable wave may saturate due to the nonlinear character of the open-quote open-quote friction close-quote close-quote term, and the stability of the nonlinear solution is analyzed. copyright 1996 The American Physical Society

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

    Science.gov (United States)

    Othman, Mohamed A. K.; Veysi, Mehdi; Figotin, Alexander; Capolino, Filippo

    2016-03-01

    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.

  3. Standing Slow-Mode Waves in Hot Coronal Loops: Observations, Modeling, and Coronal Seismology

    CERN Document Server

    Wang, Tongjiang

    2010-01-01

    Strongly damped Doppler shift oscillations are observed frequently associated with flarelike events in hot coronal loops. In this paper, a review of the observed properties and the theoretical modeling is presented. Statistical measurements of physical parameters (period, decay time, and amplitude) have been obtained based on a large number of events observed by SOHO/SUMER and Yohkoh/BCS. Several pieces of evidence are found to support their interpretation in terms of the fundamental standing longitudinal slow mode. The high excitation rate of these oscillations in small- or micro-flares suggest that the slow mode waves are a natural response of the coronal plasma to impulsive heating in closed magnetic structure. The strong damping and the rapid excitation of the observed waves are two major aspects of the waves that are poorly understood, and are the main subject of theoretical modeling. The slow waves are found mainly damped by thermal conduction and viscosity in hot coronal loops. The mode coupling seems ...

  4. Local Slow Waves in Superficial Layers of Primary Cortical Areas during REM Sleep.

    Science.gov (United States)

    Funk, Chadd M; Honjoh, Sakiko; Rodriguez, Alexander V; Cirelli, Chiara; Tononi, Giulio

    2016-02-01

    Sleep is traditionally constituted of two global behavioral states, non-rapid eye movement (NREM) and rapid eye movement (REM), characterized by quiescence and reduced responsiveness to sensory stimuli [1]. NREM sleep is distinguished by slow waves and spindles throughout the cerebral cortex and REM sleep by an "activated," low-voltage fast electroencephalogram (EEG) paradoxically similar to that of wake, accompanied by rapid eye movements and muscle atonia. However, recent evidence has shown that cortical activity patterns during wake and NREM sleep are not as global as previously thought. Local slow waves can appear in various cortical regions in both awake humans [2] and rodents [3-5]. Intracranial recordings in humans [6] and rodents [4, 7] have shown that NREM sleep slow waves most often involve only a subset of brain regions that varies from wave to wave rather than occurring near synchronously across all cortical areas. Moreover, some cortical areas can transiently "wake up" [8] in an otherwise sleeping brain. Yet until now, cortical activity during REM sleep was thought to be homogenously wake-like. We show here, using local laminar recordings in freely moving mice, that slow waves occur regularly during REM sleep, but only in primary sensory and motor areas and mostly in layer 4, the main target of relay thalamic inputs, and layer 3. This finding may help explain why, during REM sleep, we remain disconnected from the environment even though the bulk of the cortex shows wake-like, paradoxical activation. PMID:26804554

  5. Kinetic Simulation of Slow Magnetosonic Waves and Quasi-periodic Upflows in the Solar Corona

    CERN Document Server

    Ruan, Wenzhi; Zhang, Lei; Vocks, Christian; Marsch, Eckart; Tu, Chuanyi; Peter, Hardi; Wang, Linghua

    2016-01-01

    Quasi-periodic disturbances of emission-line parameters are frequently observed in the corona. These disturbances propagate upward along the magnetic field with speeds $\\sim100~\\rm{km~s}^{-1}$. This phenomenon has been interpreted as evidence of the propagation of slow magnetosonic waves or argued to be signature of the intermittent outflows superposed on the background plasmas. Here we aim to present a new "wave + flow" model to interpret these observations. In our scenario, the oscillatory motion is a slow mode wave, and the flow is associated with a beam created by the wave-particle interaction owing to Landau resonance. With the help of a Vlasov model, we simulate the propagation of the slow mode wave and the generation of the beam flow. We find that weak periodic beam flows can be generated owing to Landau resonance in the solar corona, and the phase with strongest blueward asymmetry is ahead of that with strongest blueshift by about 1/4 period. We also find that the slow wave damps to the level of 1/e a...

  6. Fast and slow flexural waves in a deviated borehole in homogeneous and layered anisotropic formations

    Science.gov (United States)

    He, Xiao; Hu, Hengshan; Guan, Wei

    2010-04-01

    Dipole acoustic fields in an arbitrarily deviated well penetrating a homogeneous as well as a stratified transversely isotropic formation are simulated using a 3-D finite-difference time-domain algorithm in cylindrical coordinates. The modelling results show that a dipole source can excite a fast- and a slow-flexural mode due to the shear wave anisotropy when the borehole is inclined with respect to the symmetry axis of transverse isotropy. Both flexural slownesses change with the wellbore deviation angle. The splitting of flexural modes is prominent in full wave arrays when the shear anisotropy is strong enough. It is revealed that the dipole orientation influences the relative amplitudes of the fast- and slow-flexural waves but it has no effect on their slownesses or phases. In a vertical well parallel to the symmetry axis, the two flexural waves degenerate and propagate at the same speed. The degenerated flexural wave travels approximately at the shear speed along the borehole wall except in a few formations. Our study shows, for example, that it is about 10 per cent slower than the shear wave in Mesaverde clayshale 5501. Even in that kind of formations, however, extraction of the fast- and slow-shear velocities from the flexural modes is still possible if the borehole deviation is large enough. To examine the effect of layering, we modelled the full waves in a formation with a sandwich. When the well is perpendicular to the layer interfaces, reflection is obvious and can be recognized. It becomes weaker or even invisible as the deviation angle increases, so it is difficult to detect a thin layer embedded in a formation directly from reflected waves. The sandwich can, instead, be recognized from the irregularity in the spectra of the full waveforms displayed versus depth. [Correction added after online publication 25th February 2009; the original spelling of `homogenous' in the title has been corrected to `homogeneous'.[

  7. Exponentially slow traveling waves on a finite interval for Burgers' type equation

    Directory of Open Access Journals (Sweden)

    Pieter De Groen

    1998-11-01

    Full Text Available In this paper we study for small positive $epsilon$ the slow motion of the solution for evolution equations of Burgers' type with small diffusion, $$ u_t=epsilon u_{xx}+f(u,u_x,, quad u(x,0=u_0(x, quad u(pm 1,t=pm 1, $$ on the bounded spatial domain $[-1,1]$; $f$ is a smooth function satisfying $f(1>0, f(-1<0$ and $int_{-1}^{1}f(tdt=0$. The initial and boundary value problem~($star$ has a unique asymptotically stable equilibrium solution that attracts all solutions starting with continuous initial data $u_0$. On the infinite spatial domain ${mathbb R}$ the differential equation has slow speed traveling wave solutions generated by profiles that satisfy the boundary conditions of~($star$. As long as its zero stays inside the interval $[-1,1]$, such a traveling wave suitably describes the slow long term behaviour of the solution of ($star$ and its speed characterizes the local velocity of the slow motion with exponential precision. A solution that starts near a traveling wave moves in a small neighborhood of the traveling wave with exponentially slow velocity (measured as the speed of the unique zero during an exponentially long time interval $(0,T$. In this paper we give a unified treatment of the problem, using both Hilbert space and maximum principle methods, and we give rigorous proofs of convergence of the solution and of the asymptotic estimate of the velocity.

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

    International Nuclear Information System (INIS)

    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. Slow wave cavity resonance in periodic stacks of anisotropic layers

    CERN Document Server

    Figotin, Alex

    2007-01-01

    We consider Fabry-Perot cavity resonance in periodic layered structures involving birefringent layers. Previously we have shown that the presence of birefringent layers with misaligned in-plane anisotropy can dramatically enhance the performance of the photonic-crystal cavity. It allows to reduce the size of a Fabry-Perot resonator by an order of magnitude without compromising on its performance. The key characteristic of the enhanced photonic-crystal cavity is that its Bloch dispersion relation displays a degenerate photonic band edge, rather than only regular ones. This can be realized in specially arranged stacks of misaligned anisotropic layers. On the down side, the presence of birefringent layers results in the Fabry-Perot resonance being coupled only with one (elliptic) polarization component of the incident wave, while the other polarization component is reflected back to space. In this paper we show how a small modification of the periodic layered array can solve the above fundamental problem and pro...

  10. Slow-light Airy wave packets and their active control via electromagnetically induced transparency

    CERN Document Server

    Hang, Chao

    2014-01-01

    We propose a scheme to generate (3+1)-dimensional slow-light Airy wave packets in a resonant $\\Lambda$-type three-level atomic gas via electromagnetically induced transparency. We show that in the absence of dispersion the Airy wave packets formed by a probe field consist of two Airy wave packets accelerated in transverse directions and a longitudinal Gaussian pulse with a constant propagating velocity lowered to $10^{-5}\\,c$ ($c$ is the light speed in vacuum). We also show that in the presence of dispersion it is possible to generate another type of slow-light Airy wave packets consisting of two Airy beams in transverse directions and an Airy wave packet in the longitudinal direction. In this case, the longitudinal velocity of the Airy wave packet can be further reduced during propagation. Additionally, we further show that the transverse accelerations (or bending) of the both types of slow-light Airy wave packets can be completely eliminated and the motional trajectories of them can be actively manipulated ...

  11. Symmetrical serotonin release during asymmetrical slow-wave sleep: implications for the neurochemistry of sleep-waking states

    OpenAIRE

    Lapierre, Jennifer L; Kosenko, Peter O; Kodama, Tohru; Peever, John H; Mukhametov, Lev M; Lyamin, Oleg I; Siegel, Jerome M.

    2013-01-01

    On land, fur seals predominately display bilaterally synchronized electroencephalogram (EEG) activity during slow-wave sleep (SWS), similar to that observed in all terrestrial mammals. In water, however, fur seals exhibit asymmetric slow-wave sleep (ASWS), resembling the unihemispheric slow-wave sleep of odontocetes (toothed whales). The unique sleeping pattern of fur seals allows us to distinguish neuronal mechanisms mediating EEG changes from those mediating behavioral quiescence. In a prio...

  12. Shock Formation and Energy Dissipation of Slow Magnetosonic Waves in Coronal Plumes

    Science.gov (United States)

    Cuntz, M.; Suess, S. T.

    2003-01-01

    We study the shock formation and energy dissipation of slow magnetosonic waves in coronal plumes. The wave parameters and the spreading function of the plumes as well as the base magnetic field strength are given by empirical constraints mostly from SOHO/UVCS. Our models show that shock formation occurs at low coronal heights, i.e., within 1.3 bun, depending on the model parameters. In addition, following analytical estimates, we show that scale height of energy dissipation by the shocks ranges between 0.15 and 0.45 Rsun. This implies that shock heating by slow magnetosonic waves is relevant at most heights, even though this type of waves is apparently not a solely operating energy supply mechanism.

  13. Linear Analysis of Folded Double-Ridged Waveguide Slow-Wave Structure for Millimeter Wave Traveling Wave Tube

    International Nuclear Information System (INIS)

    A novel slow-wave structure (SWS), the folded double-ridged waveguide structure, is presented and its linear gain properties are investigated. The perturbed dispersion equation is derived and the small signal growth rate is calculated for dimensions of the ridge-loaded region and the parameters of the electron beam. The novel structure has potential applications in the production of high power and broad band radiation. For a cold beam, the linear theory predicts a gain of 1.1–1.27 dB/period and a 3-dB small-signal gain bandwidth of 30% in W-band. A comparison between the folded double-ridged waveguide SWS and folded waveguide SWS (FWSWS) shows that with the same physical parameters, the novel SWS has an advantage over the FWSWS on the bandwidth and electron efficiency. (fundamental areas of phenomenology (including applications))

  14. Linear Analysis of Folded Double-Ridged Waveguide Slow-Wave Structure for Millimeter Wave Traveling Wave Tube

    Institute of Scientific and Technical Information of China (English)

    HE Jun; WEI Yan-Yu; GONG Yu-Bin; WANG Wen-Xiang

    2009-01-01

    A novel slow-wave structure (SWS), the folded double-ridged waveguide structure, is presented and its linear gain properties are investigated. The perturbed dispersion equation is derived and the small signal growth rate is calculated for dimensions of the ridge-loaded region and the parameters of the electron beam. The novel structure has potential applications in the production of high power and broad band radiation. For a cold beam, the linear theory predicts a gain of 1.1-1.27dB/period and a 3-dB small-signal gain bandwidth of 30% in W-band. A comparison between the folded double-ridged waveguide SWS and folded waveguide SWS (FWSWS) shows that with the same physical parameters, the novel SWS has an advantage over the FWSWS on the bandwidth and electron efficiency.

  15. 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.

  16. Cut-off period for slow magnetoacoustic waves in coronal plasma structures

    Science.gov (United States)

    Afanasyev, A. N.; Nakariakov, V. M.

    2015-10-01

    Context. There is abundant observational evidence of longitudinal compressive waves in plasma structures of the solar corona, which are confidently interpreted in terms of slow magnetoacoustic waves. The uses of coronal slow waves in plasma diagnostics, as well as analysis of their possible contribution to coronal heating and the solar wind acceleration, require detailed theoretical modelling. Aims: We investigate the effects of obliqueness, magnetic field, and non-uniformity of the medium on the evolution of long-wavelength slow magnetoacoustic waves guided by field-aligned plasma non-uniformities, also called tube waves. Special attention is paid to the cut-off effect due to the gravity stratification of the coronal plasma. Methods: We study the behaviour of linear tube waves in a vertical untwisted straight field-aligned isothermal plasma cylinder. We apply the thin flux tube approximation, taking into account effects of stratification caused by gravity. The dispersion due to the finite radius of the flux tube is neglected. We analyse the behaviour of the cut-off period for an exponentially divergent magnetic flux tube filled in with a stratified plasma. The results obtained are compared with the known cases of the constant Alfven speed and the pure acoustic wave. Results: We derive the wave equation for tube waves and reduce it to the form of the Klein-Gordon equation with varying coefficients, which explicitly contains the cut-off frequency. The cut-off period is found to vary with height, decreasing significantly in the low-beta plasma and in the plasma with the beta of the order of unity. The depressions in the cut-off period profiles can affect the propagation of longitudinal waves along coronal plasma structures towards the higher corona and can form coronal resonators.

  17. 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.

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

    International Nuclear Information System (INIS)

    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)

  19. Minipig negative slow wave demonstrates target/nontarget differences in P300 paradigm

    DEFF Research Database (Denmark)

    Arnfred, Sidse Marie; Lind, Nanna Marie; Moustgaard, Anette Caroline;

    2003-01-01

    The negative slow wave (NSW) is a late component of the event-related potential (ERP) in man modulated like the P300 by the stimulus, the task, and the response demand. Aiming at the development of a minipig model of schizophrenia, we investigated scalp ERPs in an auditory P300 paradigm in six...

  20. Compressible turbulence with slow-mode waves observed in the bursty bulk flow of plasma sheet

    Science.gov (United States)

    Wang, Tieyan; Cao, Jinbin; Fu, Huishan; Meng, Xuejie; Dunlop, M.

    2016-03-01

    In this paper, we report the evidence of compressible turbulence with slow-mode waves in a bursty bulk flow of plasma sheet. This compressible turbulence is characterized by a multiscale (1-60 s) anticorrelation between plasma density and magnetic field strength. Besides, the magnetic compressibility spectrum stays nearly constant at all the measured frequencies. Furthermore, the turbulence energy distributions are anisotropic with k⊥ > k//, and the dispersion relation is consistent with slow-mode prediction. The fluctuations of density and magnetic field have similar double slope spectrum and kurtosis. These results suggest that the slow waves are involved in the intermittent turbulence cascade from MHD to ion kinetic scales, which may have significant implications for the energy transfer in the plasma sheet.

  1. Sonic logging of compressional-wave velocities in a very slow formation

    Energy Technology Data Exchange (ETDEWEB)

    Tichelaar, B.W. [Shell Research B.V., Rijswijk (Netherlands); Luik, K.W. van [Nederlandse Aardolie Maatschappij B.V., Assen (Netherlands)

    1995-11-01

    Borehole sonic waveforms are commonly acquired to produce logs of subsurface compressional and shear wave velocities. To this purpose, modern borehole sonic tools are usually equipped with various types of acoustic sources, i.e., monopole and dipole sources. While the dipole source has been specifically developed for measuring shear wave velocities, the authors found that the dipole source has an advantage over the monopole source when determining compressional wave velocities in a very slow formation consisting of unconsolidated sands with a porosity of about 35% and a shear wave velocity of about 465 m/s. In this formation, the recorded compressional refracted waves suffer from interference with another wavefield component identified as a leaky P-wave, which hampers the determination of compressional wave velocities in the sands. For the dipole source, separation of the compressional refracted wave from the recorded waveforms is accomplished through bandpass filtering since the wavefield components appear as two distinctly separate contributions to the frequency spectrum: a compressional refracted wave centered at a frequency of 6.5 kHz and a leaky P-wave centered at 1.3 kHz. For the monopole source, the frequency spectra of the various waveform components have considerable overlap. It is therefore not obvious what passband to choose to separate the compressional refracted wave from the monopole waveforms.

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

    International Nuclear Information System (INIS)

    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 R2 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

  3. Evidence of slow magneto-acoustic waves in photospheric observations of a sunspot

    CERN Document Server

    Zharkov, S; Erdélyi, R; Thompson, M J

    2009-01-01

    We show the observational evidence for the presence of MHD waves in the solar photosphere deduced from SOHO MDI Dopplergram velocity observations. The magneto-acoustic oscillations are observed as acoustic power enhancement in the sunspot umbra at high frequency bands in the velocity component transverse to the magnetic field. We use numerical modelling of the wave propagation through localised non-uniform magnetic field concentration along with the same filtering procedure as applied to the observations to identify the observed waves. Underpinned by the results of the numerical simulations we classify the observed oscillations as slow magneto-acoustic waves excited by the trapped sub-photospheric acoustic waves. We consider the potential application of the presented method as a diagnostic tool for magnetohelioseismology.

  4. Evaluation of QT and P Wave Dispersion and Mean Platelet Volume among Inflammatory Bowel Disease Patients

    Directory of Open Access Journals (Sweden)

    Yuksel DOGAN, Aliye SOYLU, Gulay A. EREN, Sule POTUROGLU, Can DOLAPCIOGLU, Kenan SONMEZ, Habibe DUMAN, Isa SEVINDIR

    2011-01-01

    Full Text Available Background: 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.Methods: 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.Results: 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.Conclusions: 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

  5. Estimation of material parameters from slow and fast shear waves in an incompressible, transversely isotropic material.

    Science.gov (United States)

    Tweten, Dennis J; Okamoto, Ruth J; Schmidt, John L; Garbow, Joel R; Bayly, Philip V

    2015-11-26

    This paper describes a method to estimate mechanical properties of soft, anisotropic materials from measurements of shear waves with specific polarization and propagation directions. This method is applicable to data from magnetic resonance elastography (MRE), which is a method for measuring shear waves in live subjects or in vitro samples. Here, we simulate MRE data using finite element analysis. A nearly incompressible, transversely isotropic (ITI) material model with three parameters (shear modulus, shear anisotropy, and tensile anisotropy) is used, which is appropriate for many fibrous, biological tissues. Both slow and fast shear waves travel concurrently through such a material with speeds that depend on the propagation direction relative to fiber orientation. A three-parameter estimation approach based on directional filtering and isolation of slow and fast shear wave components (directional filter inversion, or DFI) is introduced. Wave speeds of each isolated shear wave component are estimated using local frequency estimation (LFE), and material properties are calculated using weighted least squares. Data from multiple finite element simulations are used to assess the accuracy and reliability of DFI for estimation of anisotropic material parameters. PMID:26476762

  6. Simulating Reflective Propagating Slow-wave/flow in a Flaring Loop

    Science.gov (United States)

    Fang, X.

    2015-12-01

    Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV 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 post flare loop. Our model encompasses the corona, transition region, and chromosphere. We demonstrate that the quasi periodic propagating intensity variations captured by our synthesized AIA 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 in an 80 Mm length loop with an average temperature of 9 MK. With the synthesized Doppler shift velocity and intensity maps in SUMER Fe XIX line emission, we confirm that these reflected slow mode waves are propagating waves.

  7. Acoustic waves in a Biot-type porous snow model: The fast slow wave in light snow

    CERN Document Server

    Sidler, Rolf

    2015-01-01

    Wave velocities, attenuation and reflection coefficients in snow can not be explained by the widely used elastic or viscoelastic models for wave propagation. Instead, Biot's model of wave propagation in porous materials should be used. However, the application of Biot's model is difficult due to the large property space of the underlying porous material. Here we use the properties of ice and air as well as empirical relationships to define the properties of snow as a function of porosity. This reduction allows to predict phase velocities and attenuation of the shear- and compressional-waves as functions of porosity or density. For light snow the peculiarity was found that the velocity of the compressional wave of the first kind is lower than the compressional wave of the second kind that is commonly referred to as the "slow" wave. The reversal of the velocities comes with an increase of attenuation for the first compressional wave. This is in line with the common observation that sound is strongly absorbed af...

  8. Evaluation of Some Slow-wave Vane Structures for Aminiature Traveling-wave Tube at 30 Ghz

    Science.gov (United States)

    Kavanagh, Frank; Ebihara, Ben; Wallett, Thomas M.; Dayton, James A., Jr.

    1994-01-01

    The dispersion characteristics of six vane type slow wave structures were experimentally measured near 1 GHz to determine applicability in an electrostatically focused 30 GHz miniature traveling wave tube (TWT). From the measured results, the trapezoidal vane structure appeared to be the most promising exhibiting an interaction impedance equal to 337.9 ohms at beta(L)/pi equal to 0.3. A 30 GHz trapezoidal vane structure with coupling irises was fabricated using electrical discharge machining (EDM). This structure, however, was too lossy for a short electrostatically focused tube, but several of the structures are amenable to a tube with permanent magnetic focusing.

  9. Evidence of Biot Slow Waves in Electroseismic Measurementss on Laboratory-Scale

    Science.gov (United States)

    Devi, M. S.

    2015-12-01

    Electroseismic methods which are the opposite of seismo-electric methods have only been little investigated up to now especially in the near surface scale. These methods can generate the solid-fluid relative movement induced by the electric potential in fluid-filled porous media. These methods are the response of electro-osmosis due to the presence of the electrical double layer. Laboratory experiments and numerical simulations of electroseismic studies have been performed. Electroseismic measurements conducted in micro glass beads saturated with demineralized water. Pair of 37 x 37 mm square aluminium grids with 2 mm of aperture and 4 mm of spacing is used as the electric dipole that connected to the electric power source with the voltage output 150 V. A laser doppler vibrometer is the system used to measure velocity of vibrating objects during measurements by placing a line of reflective paper on the surface of media that scattered back a helium-neon laser. The results in homogeneous media shows that the compressional waves induced by an electric signal. We confirm that the results are not the effects of thermal expansion. We also noticed that there are two kinds of the compressional waves are recorded: fast and slow P-waves. The latter, Biot slow waves, indicate the dominant amplitude. Moreover, we found that the transition frequency (ωc) of Biot slow waves depends on mechanical parameters such as porosity and permeability. The ωc is not affected when varying conductivity of the fluid from 25 - 320 μS/cm, although the amplitude slightly changed. For the results in two layer media by placing a sandstone as a top layer shows that a large amount of transmission seismic waves (apparently as Biot slow waves) rather than converted electromagnetic-to-seismic waves. These properties have also been simulated with full waveform numerical simulations relying on Pride's (1994) using our computer code (Garambois & Dietrich, 2002). If it is true that the electric source in

  10. A weak-wave turbulence theory for rotationally constrained slow inertial waves

    CERN Document Server

    Sen, Amrik; Pouquet, Annick

    2013-01-01

    A weak-wave turbulence theory for rapidly rotating flows is developed in this paper. The governing equations are an asymptotically reduced set of equations that are derived from the incompressible Navier-Stokes equations. These equations are applicable for rapidly rotating flow regimes and are best suited to describe anisotropic dynamics of rotating flows. The independent variables of these equations inherently reside in a helical wave basis that is the most suitable basis for inertial waves. A coupled system of equations for the two global invariants: energy and helicity, is derived by extending a simpler symmetrical system to the more general non-symmetrical helical case. Stationary solutions, including Kolmogorov solutions, for the flow invariants are obtained as a scaling law of the anisotropic wave numbers. The scaling law solutions compare affirmatively with results from recent experimental and simulation data. This theory is applicable to resonant wave interactions and hence does not capture wave-vorte...

  11. Modelling of Reflective Propagating Slow-mode Wave in a Flaring Loop

    CERN Document Server

    Fang, X; Van Doorsselaere, T; Keppens, R; Xia, C

    2015-01-01

    Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV 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 \\textit{Solar Dynamics Observatory}/Atmospheric Imaging Assembly (AIA) 131, 94~\\AA~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 in an 80 Mm length loop with an average temperatu...

  12. Radio-Frequency Characteristics of a Printed Rectangular Helix Slow-Wave Structure

    International Nuclear Information System (INIS)

    A new type of printed rectangular helix slow-wave structure (SWS) is investigated using the field-matching method and the electromagnetic integral equations at the boundaries. The radio-frequency characteristics including the dispersion equation and the coupling impedance for transverse antisymmetric (odd) modes of this structure are analysed. The numerical results agree well with the results obtained by the EM simulation software HFSS. It is shown that the dispersion of the rectangular helix circuit is weakened, the phase velocity is reduced after filling the dielectric materials in the rectangular helix SWS. As a planar slow-wave structure, this structure has potential applications in compact TWTs. (cross-disciplinary physics and related areas of science and technology)

  13. Over-reflection of slow magnetosonic waves by homogeneous shear flow: Analytical solution

    International Nuclear Information System (INIS)

    We have analyzed the amplification of slow magnetosonic (or pseudo-Alfvenic) waves (SMW) in incompressible shear flow. As found here, the amplification depends on the component of the wave-vector perpendicular to the direction of the shear flow. Earlier numerical results are consistent with the general analytic solution for the linearized magnetohydrodynamic equations, derived here for the model case of pure homogeneous shear (without Coriolis force). An asymptotically exact analytical formula for the amplification coefficient is derived for the case when the amplification is sufficiently large.

  14. 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.

  15. Synaptic refinement during development and its effect on slow-wave activity: a computational study.

    Science.gov (United States)

    Hoel, Erik P; Albantakis, Larissa; Cirelli, Chiara; Tononi, Giulio

    2016-04-01

    Recent evidence suggests that synaptic refinement, the reorganization of synapses and connections without significant change in their number or strength, is important for the development of the visual system of juvenile rodents. Other evidence in rodents and humans shows that there is a marked drop in sleep slow-wave activity (SWA) during adolescence. Slow waves reflect synchronous transitions of neuronal populations between active and inactive states, and the amount of SWA is influenced by the connection strength and organization of cortical neurons. In this study, we investigated whether synaptic refinement could account for the observed developmental drop in SWA. To this end, we employed a large-scale neural model of primary visual cortex and sections of the thalamus, capable of producing realistic slow waves. In this model, we reorganized intralaminar connections according to experimental data on synaptic refinement: during prerefinement, local connections between neurons were homogenous, whereas in postrefinement, neurons connected preferentially to neurons with similar receptive fields and preferred orientations. Synaptic refinement led to a drop in SWA and to changes in slow-wave morphology, consistent with experimental data. To test whether learning can induce synaptic refinement, intralaminar connections were equipped with spike timing-dependent plasticity. Oriented stimuli were presented during a learning period, followed by homeostatic synaptic renormalization. This led to activity-dependent refinement accompanied again by a decline in SWA. Together, these modeling results show that synaptic refinement can account for developmental changes in SWA. Thus sleep SWA may be used to track noninvasively the reorganization of cortical connections during development. PMID:26843602

  16. Midlife decline in declarative memory consolidation is correlated with a decline in slow wave sleep

    OpenAIRE

    Backhaus, Jutta; Born, Jan; Hoeckesfeld, Ralf; Fokuhl, Sylvia; Hohagen, Fritz; Junghanns, Klaus

    2007-01-01

    Sleep architecture as well as memory function are strongly age dependent. Slow wave sleep (SWS), in particular, decreases dramatically with increasing age, starting already beyond the age of 30. SWS normally predominates during early nocturnal sleep and is implicated in declarative memory consolidation. However, the consequences of changes in sleep across the life span for sleep-associated memory consolidation have not been evaluated so far. Here, we compared declarative memory consolidation ...

  17. Sleep-active cells in the cerebral cortex and their role in slow-wave activity

    OpenAIRE

    Gerashchenko, Dmitry; Wisor, Jonathan P.; Kilduff, Thomas S.

    2011-01-01

    We recently identified neurons in the cerebral cortex that become activated during sleep episodes with high slow-wave activity (SWA). The distinctive properties of these neurons are the ability to produce nitric oxide and their long-range projections within the cortex. In this review, we discuss how these characteristics of sleep-active cells could be relevant to SWA production in the cortex. We also discuss possible models of the role of nNOS cells in SWA production.

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

    International Nuclear Information System (INIS)

    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 mm3 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)

  19. Effects and mechanisms of gastrointestinal electrical stimulation on slow waves: a systematic canine study

    OpenAIRE

    Sun, Yan; Song, Geng-Qing; Yin, Jieyun; Lei, Yong; Chen, Jiande D.Z.

    2009-01-01

    The aims of this study were to determine optimal pacing parameters of electrical stimulation on different gut segments and to investigate effects and possible mechanisms of gastrointestinal electrical stimulation on gut slow waves. Twelve female hound-mix dogs were used in this study. A total of six pairs of electrodes were implanted on the stomach, duodenum, and ascending colon. Bilateral truncal vagotomy was performed in six of the dogs. One experiment was designed to study the effects of t...

  20. The epileptic syndromes with continuous spikes and waves during slow sleep: definition and management guidelines.

    OpenAIRE

    Bogaert, P; Aeby, A.; De Borchgrave, V.; De Cocq, C.; Deprez, Manuel; De Tiege, X.; de Tourtchaninoff, M.; Dubru, Jean-Marie; Foulon, Maggy; Ghariani, S.; Grisar, Thierry; Legros, B; Ossemann, M; Tugendhaft, P.; Van Rijckevorsel, K

    2006-01-01

    The authors propose to define the epileptic syndromes with continuous spikes and waves during slow sleep (CSWS) as a cognitive or behavioral impairment acquired during childhood, associated with a strong activation of the interictal epileptiform discharges during NREM sleep--whatever focal or generalized--and not related to another factor than the presence of CSWS. The type of syndrome will be defined according to the neurological and neuropsychological deficit. These syndromes have to be cla...

  1. Fast and slow wave detection in bovine cancellous bone in vitro using bandlimited deconvolution and Prony's method.

    Science.gov (United States)

    Wear, Keith; Nagatani, Yoshiki; Mizuno, Katsunori; Matsukawa, Mami

    2014-10-01

    Fast and slow waves were detected in a bovine cancellous bone sample for thicknesses ranging from 7 to 12 mm using bandlimited deconvolution and the modified least-squares Prony's method with curve fitting (MLSP + CF). Bandlimited deconvolution consistently isolated two waves with linear-with-frequency attenuation coefficients as evidenced by high correlation coefficients between attenuation coefficient and frequency: 0.997 ± 0.002 (fast wave) and 0.986 ± 0.013 (slow wave) (mean ± standard deviation). Average root-mean-squared (RMS) differences between the two algorithms for phase velocities were 5 m/s (fast wave, 350 kHz) and 13 m/s (slow wave, 750 kHz). Average RMS differences for signal loss were 1.6 dB (fast wave, 350 kHz) and 0.4 dB (slow wave, 750 kHz). Phase velocities for thickness = 10 mm were 1726 m/s (fast wave, 350 kHz) and 1455 m/s (slow wave, 750 kHz). Results show support for the model of two waves with linear-with frequency attenuation, successful isolation of fast and slow waves, good agreement between bandlimited deconvolution and MLSP + CF as well as with a Bayesian algorithm, and potential variations of fast and/or slow wave properties with bone sample thickness. PMID:25324100

  2. 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

  3. Modeling "slow movements"—Auto waves of non-elastic deformation in ductile and brittle materials and media

    Science.gov (United States)

    Makarov, P. V.; Peryshkin, A. Yu.

    2015-10-01

    In this paper, a mathematical model of propagating slow waves of non-elastic deformation, whose velocities in magnitude are between the velocities of tectonic creep and sound velocities, is proposed. It is shown that the model describes both Lueders fronts and slow waves of deformation in geo-environments and in the faults. Our model is a related dynamic model of elasto-plastic deformation of loaded medium, where fast processes of dynamic medium response to loading develop together with the formation of slow deformational wave. These slow waves of deformation in the model are treated as auto-wave processes and they are a collective response to loading, i.e. they are the result of self-organization in the medium being deformed.

  4. Experimental observation of sub-terahertz backward-wave amplification in a multi-level microfabricated slow-wave circuit

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Chan-Wook, E-mail: cw.baik@samsung.com; Ahn, Ho Young; Kim, Yongsung; Lee, Jooho; Hong, Seogwoo; Lee, Sang Hun; Choi, Jun Hee; Kim, Sunil; Kim, Jong Min; Hwang, Sungwoo [Samsung Advanced Institute of Technology, Suwon 443-803 (Korea, Republic of); Jeon, So-Yeon; Yu, SeGi [Department of Physics, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of); Collins, George; Read, Michael E.; Lawrence Ives, R. [Calabazas Creek Research, Inc., San Mateo, California 94404-1010 (United States)

    2015-11-09

    In our earlier paper dealing with dispersion retrieval from ultra-deep, reactive-ion-etched, slow-wave circuits on silicon substrates, it was proposed that splitting high-aspect-ratio circuits into multilevels enabled precise characterization in sub-terahertz frequency regime. This achievement prompted us to investigate beam-wave interaction through a vacuum-sealed integration with a 15-kV, 85-mA, thermionic, electron gun. Our experimental study demonstrates sub-terahertz, backward-wave amplification driven by an external oscillator. The measured output shows a frequency downshift, as well as power amplification, from beam loading even with low beam perveance. This offers a promising opportunity for the development of terahertz radiation sources, based on silicon technologies.

  5. 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.

  6. Validation of an Accurate Three-Dimensional Helical Slow-Wave Circuit Model

    Science.gov (United States)

    Kory, Carol L.

    1997-01-01

    The helical slow-wave circuit embodies a helical coil of rectangular tape supported in a metal barrel by dielectric support rods. Although the helix slow-wave circuit remains the mainstay of the traveling-wave tube (TWT) industry because of its exceptionally wide bandwidth, a full helical circuit, without significant dimensional approximations, has not been successfully modeled until now. Numerous attempts have been made to analyze the helical slow-wave circuit so that the performance could be accurately predicted without actually building it, but because of its complex geometry, many geometrical approximations became necessary rendering the previous models inaccurate. In the course of this research it has been demonstrated that using the simulation code, MAFIA, the helical structure can be modeled with actual tape width and thickness, dielectric support rod geometry and materials. To demonstrate the accuracy of the MAFIA model, the cold-test parameters including dispersion, on-axis interaction impedance and attenuation have been calculated for several helical TWT slow-wave circuits with a variety of support rod geometries including rectangular and T-shaped rods, as well as various support rod materials including isotropic, anisotropic and partially metal coated dielectrics. Compared with experimentally measured results, the agreement is excellent. With the accuracy of the MAFIA helical model validated, the code was used to investigate several conventional geometric approximations in an attempt to obtain the most computationally efficient model. Several simplifications were made to a standard model including replacing the helical tape with filaments, and replacing rectangular support rods with shapes conforming to the cylindrical coordinate system with effective permittivity. The approximate models are compared with the standard model in terms of cold-test characteristics and computational time. The model was also used to determine the sensitivity of various

  7. Prevalence and factors affecting rem and slow wave sleep rebound on cpap titration study in patients with obstructive sleep apnea

    OpenAIRE

    Osuna Suárez, Édgar; Siddiqui, Fouzia; Vanegas, Marco A.; Walters, Arthur S.; Chokroverty, Sudhansu

    2010-01-01

    Background. In patients with obstructive sleep apnea syndrome (OSAS) treatment with CPAP results in an increase of REM sleep and slow wave sleep, but there is limited information about the prevalence of REM rebound in patients with OSAS and possible factors related to the rebound. Objective. REM rebound (RR) and slow wave sleep rebound (SWSR) has been described as a frequent phenomenon that occurs during CPAP titration, but the quantity that qualify for RR has not been mentioned in literat...

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

    Science.gov (United States)

    Ruan, Wenzhi; He, Jiansen; Zhang, Lei; Vocks, Christian; Marsch, Eckart; Tu, Chuanyi; Peter, Hardi; Wang, Linghua

    2016-03-01

    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.

  9. 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.

  10. Slow wave structures integrated with ferromagnetic and ferro-electric thin films for smart RF applications

    Science.gov (United States)

    Rahman, B. M. Farid

    Modern communications systems are following a common trend to increase the operational frequency, level of integration and number of frequency bands. Although 90-95% components in a cell phone are passives which take 80% of the total board area. High performance RF passive components play limited role and are desired towards this technological advancement. Slow wave structure is one of the most promising candidates to design compact RF and mm-Wave passive components. Slow wave structures are the specially designed transmission line realized by placing the alternate narrow and wide signal conductors in order to reduce the physical size of the components. This dissertation reports multiband slow wave structures integrated with ferromagnetic and ferroelectric thin films and their RF applications. A comparative study on different types of coplanar wave-guide (CPW) slow wave structures (SWS) has been demonstrated for the first time. Slow wave structures with various shapes have been investigated and optimized with various signal conductor shapes, ground conductor shapes and pitch of the sections. Novel techniques i.e. the use of the defected ground structure and the different signal conductor length has been implemented to achieve higher slow wave effect with minimum loss. The measured results have shown the reduction of size over 43.47% and 37.54% in the expense of only 0.27dB and 0.102dB insertion loss respectively which can reduce the area of a designed branch line coupler by 68% and 61% accordingly. Permalloy (Py) is patterned on top of the developed SWS for the first time to further increase the slow wave effect and provide tunable inductance value. High frequency applications of Py are limited by its ferro-magnetic resonance frequency since the inductance value decreases beyond that. Sub-micrometer patterning of Py has increased FMR frequency until 6.3GHz and 3.2GHz by introducing the shape anisotropy. For the SWS with patterned Py, the size of the quarter

  11. Using COMSOL Multiphysics Software to Model Anisotropic Dielectric and Metamaterial Effects in Folded-Waveguide Traveling-Wave Tube Slow-Wave Circuits

    Science.gov (United States)

    Starinshak, David P.; Smith, Nathan D.; Wilson, Jeffrey D.

    2008-01-01

    The electromagnetic effects of conventional dielectrics, anisotropic dielectrics, and metamaterials were modeled in a terahertz-frequency folded-waveguide slow-wave circuit. Results of attempts to utilize these materials to increase efficiency are presented.

  12. A novel slotted helix slow-wave structure for high power Ka-band traveling-wave tubes

    International Nuclear Information System (INIS)

    A novel slotted helix slow-wave structure (SWS) is proposed to develop a high power, wide-bandwidth, and high reliability millimeter-wave traveling-wave tube (TWT). This novel structure, which has higher heat capacity than a conventional helix SWS, evolves from conventional helix SWS with three parallel rows of rectangular slots made in the outside of the helix tape. In this paper, the electromagnetic characteristics and the beam-wave interaction of this novel structure operating in the Ka-band are investigated. From our calculations, when the designed beam voltage and beam current are set to be 18.45 kV and 0.2 A, respectively, this novel circuit can produce over 700-W average output power in a frequency range from 27.5 GHz to 32.5 GHz, and the corresponding conversion efficiency values vary from 19% to 21.3%, and the maximum output power is 787 W at 30 GHz. (interdisciplinary physics and related areas of science and technology)

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

    International Nuclear Information System (INIS)

    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 TM020 mode of reflector to higher-order TM021 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

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

    Science.gov (United States)

    Smirnov, A. V.; Savin, E.

    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.

  15. Quadrupole slow-wave deflector for chopping charged-particle beams

    International Nuclear Information System (INIS)

    We introduce a new beam-deflector design for chopping low-energy charged-particle beams, the quadrupole slow-wave deflector (QSWD). This new design integrates the traveling-wave beam deflector, an electrostatic quadrupole, and clearing electrodes into a single compact structure. The four-electrode device performs ion clearing and linear focusing in the quadrupole (or transmit) mode, and also serves as a fast kicker in the deflecting mode. A QSWD operates with a constantly sustained electric field that sweeps off the ions and electrons produced by beam-gas scattering. Thus, a chopper using the QSWD can avoid beam neutralization with consequent emittance growth due to the beam-plasma interaction. We shall present the theoretical studies and the design considerations of the quadrupole deflector. A conceptual design of the chopper for a proposed Long Pulse Spallation Neutron Source (LPSS) at Los Alamos will be given as an example. (author)

  16. All-metal metamaterial slow-wave structure for high-power sources with high efficiency

    International Nuclear Information System (INIS)

    In this paper, we have proposed a metamaterial (MTM) which is suitable for the compact high-power vacuum electron devices. For example, an S-band slow-wave structure (SWS) based on the all-metal MTMs has been studied by both simulation and experiment. The results show that this MTM SWS is very helpful to miniaturize the high-power vacuum electron devices and largely improve the output power and the electronic efficiency. The simulation model of an S-band MTM backward wave oscillator (BWO) is built, and the particle-in-cell simulated results are presented here: a 2.454 GHz signal is generated and its peak output power is 4.0 MW with a higher electronic efficiency of 31.5% relative to the conventional BWOs

  17. Transversal and longitudinal mode selections in double-corrugation coaxial slow-wave devices

    International Nuclear Information System (INIS)

    To reduce the dimensions of relativistic backward wave oscillators (RBWOs) operating in the low frequency regime of less than 2 GHz, the theory of transversal and longitudinal mode selections are introduced in this paper. The transversal mode selection is achieved using the property of ''surface wave'' of the coaxial slow-wave structure (SWS) to excite the quasi transverse electromagnetic (quasi-TEM) mode without the higher transverse magnetic (TM) modes and it is proved that the coaxial SWS may decrease the transversal dimension of the SWS sections. In addition, the S-parameter method is employed to investigate the longitudinal resonant characteristic of the finite-length SWS, and the scheme of longitudinal mode selection is put forward. It is proposed that the introduction of a well-designed coaxial extractor to slow-wave devices can help to achieve the longitudinal mode selection and reduce the period number of the SWS, which not only can make the devices more compact, but also can avoid the destructive competition between various longitudinal modes, therefore can enhance the efficiency and stabilize the frequency. To sum up, the physical mechanisms of transversal and longitudinal mode selections ensure that the microwave is produced with a single mode and a narrow band. Based on the above discussion, a compact L-band coaxial RBWO is investigated and optimized in detail with the particle-in-cell KARAT code (V. P. Tarakanov, Berkeley Research Associates, Inc., 1992). In simulation, the L-band coaxial RBWO, driven by a 700 kV, 11 kA electron beam, comes to a nonlinear steady state in 20 ns. High-power microwave of quasi-TEM mode is generated with an average power of 2.66 GW, a frequency of 1.6 GHz, and power conversion efficiency of 34.5% in durations of 30-60 ns.

  18. Transversal and longitudinal mode selections in double-corrugation coaxial slow-wave devices

    Science.gov (United States)

    Ge, Xingjun; Zhong, Huihuang; Qian, Baoliang; Liu, Lie; Liu, Yonggui; Li, Limin; Shu, Ting; Zhang, Jiande

    2009-06-01

    To reduce the dimensions of relativistic backward wave oscillators (RBWOs) operating in the low frequency regime of less than 2 GHz, the theory of transversal and longitudinal mode selections are introduced in this paper. The transversal mode selection is achieved using the property of "surface wave" of the coaxial slow-wave structure (SWS) to excite the quasi transverse electromagnetic (quasi-TEM) mode without the higher transverse magnetic (TM) modes and it is proved that the coaxial SWS may decrease the transversal dimension of the SWS sections. In addition, the S-parameter method is employed to investigate the longitudinal resonant characteristic of the finite-length SWS, and the scheme of longitudinal mode selection is put forward. It is proposed that the introduction of a well-designed coaxial extractor to slow-wave devices can help to achieve the longitudinal mode selection and reduce the period number of the SWS, which not only can make the devices more compact, but also can avoid the destructive competition between various longitudinal modes, therefore can enhance the efficiency and stabilize the frequency. To sum up, the physical mechanisms of transversal and longitudinal mode selections ensure that the microwave is produced with a single mode and a narrow band. Based on the above discussion, a compact L-band coaxial RBWO is investigated and optimized in detail with the particle-in-cell KARAT code (V. P. Tarakanov, Berkeley Research Associates, Inc., 1992). In simulation, the L-band coaxial RBWO, driven by a 700 kV, 11 kA electron beam, comes to a nonlinear steady state in 20 ns. High-power microwave of quasi-TEM mode is generated with an average power of 2.66 GW, a frequency of 1.6 GHz, and power conversion efficiency of 34.5% in durations of 30-60 ns.

  19. Properties of short-wavelength oblique Alfvén and slow waves

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, J. S.; Wu, D. J. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Voitenko, Y. [Solar-Terrestrial Centre of Excellence, Space Physics Division, Belgian Institute for Space Aeronomy, Avenue Circulaire 3, B-1180 Brussels (Belgium); Yu, M. Y. [Institute for Fusion Theory and Simulation and Department of Physics, Zhejiang University, Hangzhou 310027 (China); Lu, J. Y., E-mail: jszhao@pmo.ac.cn [College of Math and Statistics, Nanjing University of Information Science and Technology, Nanjing 210044 (China)

    2014-10-01

    Linear properties of kinetic Alfvén waves (KAWs) and kinetic slow waves (KSWs) are studied in the framework of two-fluid magnetohydrodynamics. We obtain the wave dispersion relations that are valid in a wide range of the wave frequency ω and plasma-to-magnetic pressure ratio β. The KAW frequency can reach and exceed the ion-cyclotron frequency at ion kinetic scales, whereas the KSW frequency remains sub-cyclotron. At β ∼ 1, the plasma and magnetic pressure perturbations of both modes are in anti-phase, so that there is nearly no total pressure perturbations. However, these modes also exhibit several opposite properties. At high β, the electric polarization ratios of KAWs and KSWs are opposite at the ion gyroradius scale, where KAWs are polarized in the sense of electron gyration (right-hand polarized) and KSWs are left-hand polarized. The magnetic helicity σ ∼ 1 for KAWs and σ ∼ –1 for KSWs, and the ion Alfvén ratio R{sub Ai} << 1 for KAWs and R{sub Ai} >> 1 for KSWs. We also found transition wavenumbers where KAWs change their polarization from left-handed to right-handed. These new properties can be used to discriminate KAWs and KSWs when interpreting kinetic-scale electromagnetic fluctuations observed in various solar-terrestrial plasmas. This concerns, in particular, identification of modes responsible for kinetic-scale pressure-balanced fluctuations and turbulence in the solar wind.

  20. Low-frequency P-wave logging for improved compressional velocity in slow formation gas zones

    Energy Technology Data Exchange (ETDEWEB)

    Wu, P.T.; Darling, H.L.; Scheibner, D.

    1995-12-31

    The ratio of compressional to shear velocity is commonly used as a gas indicator, for seismic correlation, and for rock mechanical properties evaluation in the oil industry. However, in soft rock gas zone, it is difficult to obtain a good measure of compressional velocity. Traditional monopole sonic logging tools operate with source frequencies above 10 kHz, giving rise to large amplitude borehole fluid modes which dominate compressional wave traveling with speed slower than the fluid speed. Numerical modeling of monopole sonic waveforms in a fluid-filled borehole in porous formations confirms these observations, but also shows that at significantly lower frequencies two important changes occur: (1) the non-Stoneley fluid modes becomes extremely small, and (2) the P-wave amplitude is greatly increased. Therefore, at low frequencies, logging of these very slow P-waves in gas zones should be feasible. A field example shows the value of this low frequency technique, resulting in measurements of P-wave velocities substantially lower than the fluid speed.

  1. Slow-wave activity saturation and thalamocortical isolation during propofol anesthesia in humans.

    Science.gov (United States)

    Ní Mhuircheartaigh, Róisín; Warnaby, Catherine; Rogers, Richard; Jbabdi, Saad; Tracey, Irene

    2013-10-23

    The altered state of consciousness produced by general anesthetics is associated with a variety of changes in the brain's electrical activity. Under hyperpolarizing influences such as anesthetic drugs, cortical neurons oscillate at ~1 Hz, which is measurable as slow waves in the electroencephalogram (EEG). We have administered propofol anesthesia to 16 subjects and found that, after they had lost behavioral responsiveness (response to standard sensory stimuli), each individual's EEG slow-wave activity (SWA) rose to saturation and then remained constant despite increasing drug concentrations. We then simultaneously collected functional magnetic resonance imaging and EEG data in 12 of these subjects during propofol administration and sensory stimulation. During the transition to SWA saturation, the thalamocortical system became isolated from sensory stimuli, whereas internal thalamocortical exchange persisted. Rather, an alternative and more fundamental cortical network (which includes the precuneus) responded to all sensory stimulation. We conclude that SWA saturation is a potential individualized indicator of perception loss that could prove useful for monitoring depth of anesthesia and studying altered states of consciousness. PMID:24154602

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

    Science.gov (United States)

    French, David M; Shiffler, Don

    2016-05-01

    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. PMID:27250415

  3. Coronal seismology of flare-excited longitudinal slow magnetoacoustic waves in hot coronal loops

    Science.gov (United States)

    Wang, T.; Ofman, L.; Sun, X.; Provornikova, E. A.; Davila, J. M.

    2015-12-01

    The flare-excited longitudinal intensity oscillations in hot flaring loops have been recently detected by SDO/AIA in 94 and 131 bandpasses. These oscillations show similar physical properties (such as period, decay time, and trigger) as those slow-mode standing waves previously detected by the SOHO/SUMER spectrometer in Doppler shift of flare lines formed above 6 MK. The multi-wavelength AIA observations with high spatio-temporal resolution and wide temperature coverage enable us to measure both thermal and wave properties of the oscillating hot plasma with unprecedented accuracy. These new measurements can be used to diagnose the complicated energy transport processes in flare plasma by a technique called coronal seismology based on the combination of observations and MHD wave theory. From a detailed case study we have found evidence for thermal conduction suppression in hot loops by measuring the polytropic index and analyzing the phase relationship between the temperature and density wave signals. This result is not only crucial for better understanding the wave dissipation mechanism but also provides an alternative mechanism to explain the puzzles of long-duration events and X-ray loop-top sources which show much slower cooling than expected by the classical Spitzer conductive cooling. This finding may also shed a light on the coronal heating problem because weak thermal conductivity implies slower cooling of hot plasma in nanoflares, so increasing the average coronal temperature for the same heating rate. We will discuss the effects of thermal conduction suppression on the wave damping and loop cooling based on MHD simulations.

  4. Giant Amplification in Degenerate Band Edge Slow-Wave Structures Interacting with an Electron Beam

    CERN Document Server

    Othman, Mohamed A K; Figotin, Alexander; Capolino, Filippo

    2015-01-01

    We advance here a new amplification regime based on synchronous operation of four degenerate electromagnetic (EM) modes and the electron beam referred to as super synchronization. These four EM modes arise in a Fabry-Perot cavity (FPC) 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 allowing for synchronization with only a single EM mode. We construct a mutli transmission line (MTL) model for a loaded waveguide slow-wave structure exhibiting a DBE, and investigate the phenomenon of giant gain via super synchronization using generalized Pierce model.

  5. Compact broadband slow wave system based on spoof plasmonic THz waveguide with meander grooves

    Science.gov (United States)

    Yang, Bao Jia; Zhou, Yong Jin

    2015-12-01

    Conformal surface plasmons (CSPs) on ultrathin corrugated metallic strips have been proposed to develop versatile spoof plasmonic subwavelength integrated devices at lower frequencies bands, especially at terahertz (THz) frequencies. However, the effects of the groove shapes have not been fully investigated. Here we have proposed the CSPs waveguide constructed by meander grooves on an ultrathin dielectric substrate. The dispersions and propagation characteristics of the CSPs on the proposed waveguide have been investigated in the THz frequencies. A very compact broadband slow wave system based on such waveguide has been demonstrated, whose lateral dimension decreases about 43.2% than that based on the conventional CSPs waveguide. To verify the performance of the THz plasmonic device, we implemented experimental validation in the microwave frequencies by scaling up its geometry structure. It is believed that the CSPs waveguide and device can find more applications in the surface plasmonic THz platform such as signal processing and optical communication system.

  6. Experimental observation of ultrasound fast and slow waves through three-dimensional printed trabecular bone phantoms.

    Science.gov (United States)

    Mézière, F; Juskova, P; Woittequand, J; Muller, M; Bossy, E; Boistel, Renaud; Malaquin, L; Derode, A

    2016-02-01

    In this paper, ultrasound measurements of 1:1 scale three-dimensional (3D) printed trabecular bone phantoms are reported. The micro-structure of a trabecular horse bone sample was obtained via synchrotron x-ray microtomography, converted to a 3D binary data set, and successfully 3D-printed at scale 1:1. Ultrasound through-transmission experiments were also performed through a highly anisotropic version of this structure, obtained by elongating the digitized structure prior to 3D printing. As in real anisotropic trabecular bone, both the fast and slow waves were observed. This illustrates the potential of stereolithography and the relevance of such bone phantoms for the study of ultrasound propagation in bone. PMID:26936578

  7. Laminar crossed-field flow stability in slow wave cavities: A singularity-free approach

    International Nuclear Information System (INIS)

    A linear stability approach free from the singularities of the cold fluid theory is applied to laminar ExB flows in slow wave cavities. Employing time scale separation in the appropriate frame of reference, one avoids singularities in the guiding center motion near the drift and drift-cyclotron resonances ω-ku0(x)=nΩ, n=0,±1. Instead of an a priori Fourier mode expansion, a boundary value problem is solved with a traveling wave boundary condition at the wall. The space-charge potential is obtained in closed form using the Green's function approach. Due to the incompressibility of the flow, charge perturbations and energy exchange take place at the free flow boundaries (surface perturbations). A local expansion of the Green's function in terms of the perturbation amplitude and its derivative at the boundary yields the self-consistent closure. The loaded cavity mode profiles are everywhere free from singularities, exhibiting local maxima at the flow boundaries, not at the resonant layer(s). The small signal growth is biexponential ∝eΓt2, where Γ scales as the diocotron frequency squared Ω2D=ω4p/Ω2, and is independent of the frequency detuning from resonance. The method is compared to the normal mode analysis and the vacuum mode expansion technique. copyright 1995 American Institute of Physics

  8. Radio-frequency sheath voltages and slow wave electric field spatial structure

    International Nuclear Information System (INIS)

    We investigate theoretically how sheath radio-frequency (RF) oscillations relate to the spatial structure of the RF parallel electric field emitted by Ion Cyclotron (IC) wave launchers, using a simple model of Slow Wave (SW) evanescence coupled with Direct Current (DC) plasma biasing via sheath boundary conditions in a plasma-filled 2-dimensional (parallel, radial) rectangle. Within a “wide sheaths” asymptotic regime, valid for large-amplitude near RF fields, our model becomes partly linear: the sheath oscillating voltage at open field line boundaries is a linear combination of elementary contributions by every source point of the radiated RF field map. These individual contributions are all the more intense as the SW emission point is toroidally nearer to the sheath walls. A limit formula is given for a source infinitely close to the sheaths. The decay of sheath RF voltages with the sheath/source parallel distance is quantified as a function of two characteristic SW evanescence lengths. Decay lengths are smaller than antenna parallel extensions. The sheath RF voltages at an IC antenna side limiter are therefore mainly sensitive to SW emission near this limiter, as recent observations suggest. Toroidal proximity effects could also explain why sheath oscillations persist with antisymmetric strap toroidal phasing, despite the parallel anti-symmetry of the radiated field map. They could also justify current attempts at reducing the RF fields induced near antenna boxes to attenuate sheath oscillations in their vicinity

  9. Radio-frequency sheath voltages and slow wave electric field spatial structure

    Energy Technology Data Exchange (ETDEWEB)

    Colas, Laurent, E-mail: laurent.colas@cea.fr; Lu, Ling-Feng [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Křivská, Alena [LPP-ERM-KMS, TEC partner, Brussels (Belgium); Jacquot, Jonathan [Max-Planck-Institut für Plasmaphysik, Garching (Germany)

    2015-12-10

    We investigate theoretically how sheath radio-frequency (RF) oscillations relate to the spatial structure of the RF parallel electric field emitted by Ion Cyclotron (IC) wave launchers, using a simple model of Slow Wave (SW) evanescence coupled with Direct Current (DC) plasma biasing via sheath boundary conditions in a plasma-filled 2-dimensional (parallel, radial) rectangle. Within a “wide sheaths” asymptotic regime, valid for large-amplitude near RF fields, our model becomes partly linear: the sheath oscillating voltage at open field line boundaries is a linear combination of elementary contributions by every source point of the radiated RF field map. These individual contributions are all the more intense as the SW emission point is toroidally nearer to the sheath walls. A limit formula is given for a source infinitely close to the sheaths. The decay of sheath RF voltages with the sheath/source parallel distance is quantified as a function of two characteristic SW evanescence lengths. Decay lengths are smaller than antenna parallel extensions. The sheath RF voltages at an IC antenna side limiter are therefore mainly sensitive to SW emission near this limiter, as recent observations suggest. Toroidal proximity effects could also explain why sheath oscillations persist with antisymmetric strap toroidal phasing, despite the parallel anti-symmetry of the radiated field map. They could also justify current attempts at reducing the RF fields induced near antenna boxes to attenuate sheath oscillations in their vicinity.

  10. 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

  11. On the Properties of Slow MHD Sausage Waves within Small-scale Photospheric Magnetic Structures

    Science.gov (United States)

    Freij, N.; Dorotovič, I.; Morton, R. J.; Ruderman, M. S.; Karlovský, V.; Erdélyi, R.

    2016-01-01

    The presence of magnetoacoustic waves in magnetic structures in the solar atmosphere is well-documented. Applying the technique of solar magneto-seismology (SMS) allows us to infer the background properties of these structures. Here, we aim to identify properties of the observed magnetoacoustic waves and study the background properties of magnetic structures within the lower solar atmosphere. Using the Dutch Open Telescope and Rapid Oscillations in the Solar Atmosphere instruments, we captured two series of high-resolution intensity images with short cadences of two isolated magnetic pores. Combining wavelet analysis and empirical mode decomposition (EMD), we determined characteristic periods within the cross-sectional (i.e., area) and intensity time series. Then, by applying the theory of linear magnetohydrodynamics (MHD), we identified the mode of these oscillations within the MHD framework. Several oscillations have been detected within these two magnetic pores. Their periods range from 3 to 20 minutes. Combining wavelet analysis and EMD enables us to confidently find the phase difference between the area and intensity oscillations. From these observed features, we concluded that the detected oscillations can be classified as slow sausage MHD waves. Furthermore, we determined several key properties of these oscillations such as the radial velocity perturbation, the magnetic field perturbation, and the vertical wavenumber using SMS. The estimated range of the related wavenumbers reveals that these oscillations are trapped within these magnetic structures. Our results suggest that the detected oscillations are standing harmonics, and this allows us to estimate the expansion factor of the waveguides by employing SMS. The calculated expansion factor ranges from 4 to 12.

  12. Epileptic syndromes with continuous spike-waves during slow-sleep: new insights into pathophysiology from functional cerebral imaging

    OpenAIRE

    De Tiège, Xavier

    2009-01-01

    Epileptic syndromes with continuous spikes and waves during slow sleep (CSWS) are age-related epileptic encephalopathy characterized by the development of various psychomotor regressions in close temporal concordance with the appearance of the electroencephalogram (EEG) pattern of CSWS (Tassinari et al. 2000). This EEG pattern consists in sleep-related activation and diffusion of spike-wave discharges during usually more than 85% of non-rapid eye movement (non-REM) sleep (Tassinari et al. 200...

  13. Reflection of Propagating Slow Magneto-acoustic Waves in Hot Coronal Loops: Multi-instrument Observations and Numerical Modeling

    Science.gov (United States)

    Mandal, Sudip; Yuan, Ding; Fang, Xia; Banerjee, Dipankar; Pant, Vaibhav; Van Doorsselaere, Tom

    2016-09-01

    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.

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

    Science.gov (United States)

    Tesler, Noemi; Gerstenberg, Miriam; Franscini, Maurizia; Jenni, Oskar G; Walitza, Susanne; Huber, Reto

    2016-01-01

    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. PMID:26870661

  15. β-amyloid disrupts human NREM slow waves and related hippocampus-dependent memory consolidation.

    Science.gov (United States)

    Mander, Bryce A; Marks, Shawn M; Vogel, Jacob W; Rao, Vikram; Lu, Brandon; Saletin, Jared M; Ancoli-Israel, Sonia; Jagust, William J; Walker, Matthew P

    2015-07-01

    Independent evidence associates β-amyloid pathology with both non-rapid eye movement (NREM) sleep disruption and memory impairment in older adults. However, whether the influence of β-amyloid pathology on hippocampus-dependent memory is, in part, driven by impairments of NREM slow wave activity (SWA) and associated overnight memory consolidation is unknown. Here we show that β-amyloid burden in medial prefrontal cortex (mPFC) correlates significantly with the severity of impairment in NREM SWA generation. Moreover, reduced NREM SWA generation was further associated with impaired overnight memory consolidation and impoverished hippocampal-neocortical memory transformation. Furthermore, structural equation models revealed that the association between mPFC β-amyloid pathology and impaired hippocampus-dependent memory consolidation was not direct, but instead statistically depended on the intermediary factor of diminished NREM SWA. By linking β-amyloid pathology with impaired NREM SWA, these data implicate sleep disruption as a mechanistic pathway through which β-amyloid pathology may contribute to hippocampus-dependent cognitive decline in the elderly. PMID:26030850

  16. Development of the brain's default mode network from wakefulness to slow wave sleep.

    Science.gov (United States)

    Sämann, Philipp G; Wehrle, Renate; Hoehn, David; Spoormaker, Victor I; Peters, Henning; Tully, Carolin; Holsboer, Florian; Czisch, Michael

    2011-09-01

    Falling asleep is paralleled by a loss of conscious awareness and reduced capacity to process external stimuli. Little is known on sleep-associated changes of spontaneously synchronized anatomical networks as detected by resting-state functional magnetic resonance imaging (rs-fMRI). We employed functional connectivity analysis of rs-fMRI series obtained from 25 healthy participants, covering all non-rapid eye movement (NREM) sleep stages. We focused on the default mode network (DMN) and its anticorrelated network (ACN) that are involved in internal and external awareness during wakefulness. Using independent component analysis, cross-correlation analysis (CCA), and intraindividual dynamic network tracking, we found significant changes in DMN/ACN integrity throughout the NREM sleep. With increasing sleep depth, contributions of the posterior cingulate cortex (PCC)/retrosplenial cortex (RspC), parahippocampal gyrus, and medial prefrontal cortex to the DMN decreased. CCA revealed a breakdown of corticocortical functional connectivity, particularly between the posterior and anterior midline node of the DMN and the DMN and the ACN. Dynamic tracking of the DMN from wakefulness into slow wave sleep in a single subject added insights into intraindividual network fluctuations. Results resonate with a role of the PCC/RspC for the regulation of consciousness. We further submit that preserved corticocortical synchronization could represent a prerequisite for maintaining internal and external awareness. PMID:21330468

  17. Analysis of the power capacity characteristics of coaxial slow-wave structures

    Science.gov (United States)

    Bai, Zhen; Zhang, Jun; Zhong, Huihuang; Zhang, Dian; Meng, Dong

    2016-06-01

    Coaxial O-type Cerenkov devices usually operate in the quasi-TEM or TM01 mode, but the power capacity characteristics of these modes in coaxial slow-wave structures (SWSs) have not been published thus far. This paper presents numerical studies of the power capacity characteristics of the quasi-TEM and TM01 modes in coaxial SWSs. The results suggest that the power capacity of the TM01 mode is not significantly higher than that of the quasi-TEM mode, unless the distance between the inner and outer conductors is less than a critical value. A comparison of the power capacities of the TM01 mode in coaxial and hollow SWSs is reported for the first time. When the distance between the inner and outer conductors of coaxial SWSs is small enough or the outer radius is large enough, the power capacity of the TM01 mode in coaxial SWSs is higher than that of the TM01 mode in hollow SWSs with the same outer radius.

  18. 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

  19. Regional scalp EEG slow-wave synchronization during sleep cyclic alternating pattern A1 subtypes.

    Science.gov (United States)

    Ferri, Raffaele; Rundo, Francesco; Bruni, Oliviero; Terzano, Mario G; Stam, Cornelis J

    2006-09-01

    The levels of EEG synchronization, in the 0.25-2.5 Hz band, during the A1 subtypes of the sleep "cyclic alternating pattern" (CAP) were measured in five healthy subjects by means of the synchronization likelihood (SL) algorithm. SL was measured for seven electrode pairs (F4-F3, C4-C3, P4-P3 for the analysis of interhemispheric SL and F4-C4, C4-P4, F3-C3, and C3-P3, for the analysis of intrahemispheric SL). During the A1 CAP subtypes, SL tended to be highest between pairs of electrodes situated over different hemispheres; in particular, SL obtained from F4-F3 was the highest, followed by that of P4-P3. These results indicate that the transient high level of synchronization in the slow-wave EEG range, during the sleep A1 CAP subtypes, is a phenomenon involving mostly the anterior parts of the brain and is probably based on interhemispheric interactions, possibly mediated by transcallosal connections. PMID:16806696

  20. 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.

  1. Magnetic resonance elastography of slow and fast shear waves illuminates differences in shear and tensile moduli in anisotropic tissue.

    Science.gov (United States)

    Schmidt, J L; Tweten, D J; Benegal, A N; Walker, C H; Portnoi, T E; Okamoto, R J; Garbow, J R; Bayly, P V

    2016-05-01

    Mechanical anisotropy is an important property of fibrous tissues; for example, the anisotropic mechanical properties of brain white matter may play a key role in the mechanics of traumatic brain injury (TBI). The simplest anisotropic material model for small deformations of soft tissue is a nearly incompressible, transversely isotropic (ITI) material characterized by three parameters: minimum shear modulus (µ), shear anisotropy (ϕ=µ1µ-1) and tensile anisotropy (ζ=E1E2-1). These parameters can be determined using magnetic resonance elastography (MRE) to visualize shear waves, if the angle between the shear-wave propagation direction and fiber direction is known. Most MRE studies assume isotropic material models with a single shear (µ) or tensile (E) modulus. In this study, two types of shear waves, "fast" and "slow", were analyzed for a given propagation direction to estimate anisotropic parameters µ, ϕ, and ζ in two fibrous soft materials: turkey breast ex vivo and aligned fibrin gels. As expected, the speed of slow shear waves depended on the angle between fiber direction and propagation direction. Fast shear waves were observed when the deformations due to wave motion induced stretch in the fiber direction. Finally, MRE estimates of anisotropic mechanical properties in turkey breast were compared to estimates from direct mechanical tests. PMID:26920505

  2. Pearson相关系数法快慢横波波场分离%Wave filed separation of fast-slow shear waves by Pearson correlation coefficient method

    Institute of Scientific and Technical Information of China (English)

    王凯; 冯晅; 刘财

    2012-01-01

    横波分裂是各向异性介质的重要特征,当横波或转换波穿过各向异性介质到达地面时,地面三分量检波器的x分量和y分量接收到的地震记录中都会同时存在快横波和慢横波.将快横波和慢横波进行分离,进而计算介质的各向异性参数是多分量数据处理中重要的一步.将数学中的Pearson相关系数引入到多分量地震勘探中,提出了Pearson相关系数法进行旋转角度识别,进而分离快、慢横波波场.相比于传统的互相关法,Pearson相关系数法从精度、抗噪性能和计算效率上都有提高.%Shear-wave splitting is an important characteristic of anisotropic media. Generally, when S or P-SV waves reach to the ground through anisotropic media, the seismic record received by x component and y component of three-component detector contains fast wave and slow wave simultaneously- Separating fast wave and slow wave and then calculating the anisotropic parameters of media are an important step in multi-component data processing. The authors introduce the Pearson correlation coefficients into multi-component seismic exploration and propose the Pearson correlation coefficients to detect the rotation angle and then separate the fast wave and slow wave. Compared with the traditional cross-correlation method, the Pearson correlation coefficient method is better in accuracy, noise immunity and computational efficiency.

  3. FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Linear Analysis of Folded Double-Ridged Waveguide Slow-Wave Structure for Millimeter Wave Traveling Wave Tube

    Science.gov (United States)

    He, Jun; Wei, Yan-Yu; Gong, Yu-Bin; Wang, Wen-Xiang

    2009-11-01

    A novel slow-wave structure (SWS), the folded double-ridged waveguide structure, is presented and its linear gain properties are investigated. The perturbed dispersion equation is derived and the small signal growth rate is calculated for dimensions of the ridge-loaded region and the parameters of the electron beam. The novel structure has potential applications in the production of high power and broad band radiation. For a cold beam, the linear theory predicts a gain of 1.1-1.27 dB/period and a 3-dB small-signal gain bandwidth of 30% in W-band. A comparison between the folded double-ridged waveguide SWS and folded waveguide SWS (FWSWS) shows that with the same physical parameters, the novel SWS has an advantage over the FWSWS on the bandwidth and electron efficiency.

  4. 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.

  5. Reduced slow-wave rebound during daytime recovery sleep in middle-aged subjects.

    Directory of Open Access Journals (Sweden)

    Marjolaine Lafortune

    Full Text Available Cortical synchronization during NREM sleep, characterized by electroencephalographic slow waves (SW 75 µV, is strongly related to the number of hours of wakefulness prior to sleep and to the quality of the waking experience. Whether a similar increase in wakefulness length leads to a comparable enhancement in NREM sleep cortical synchronization in young and older subjects is still a matter of debate in the literature. Here we evaluated the impact of 25-hours of wakefulness on SW during a daytime recovery sleep episode in 29 young (27 y ± 5, and 34 middle-aged (51 y ± 5 subjects. We also assessed whether age-related changes in NREM sleep cortical synchronization predicts the ability to maintain sleep during daytime recovery sleep. Compared to baseline sleep, sleep efficiency was lower during daytime recovery sleep in both age-groups but the effect was more prominent in the middle-aged than in the young subjects. In both age groups, SW density, amplitude, and slope increased whereas SW positive and negative phase duration decreased during daytime recovery sleep compared to baseline sleep, particularly in anterior brain areas. Importantly, compared to young subjects, middle-aged participants showed lower SW density rebound and SW positive phase duration enhancement after sleep deprivation during daytime recovery sleep. Furthermore, middle-aged subjects showed lower SW amplitude and slope enhancements after sleep deprivation than young subjects in frontal and prefrontal derivations only. None of the SW characteristics at baseline were associated with daytime recovery sleep efficiency. Our results support the notion that anterior brain areas elicit and may necessitate more intense recovery and that aging reduces enhancement of cortical synchronization after sleep loss, particularly in these areas. Age-related changes in the quality of wake experience may underlie age-related reduction in markers of cortical synchronization enhancement after

  6. 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

  7. 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.

  8. 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.

  9. Experimental Investigation on Low Magnetic Field Operation of an Overmoded Slow-Wave High-Power Microwave Generator

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun; ZHONG Hui-Huang; SHU Ting; LUO Ling; WANG Yong

    2004-01-01

    @@ The experimental results of an overmoded slow-wave high-power microwave generator operated at low magnetic field are presented. The feasibility of low magnetic field operation is investigated both theoretically and experimentally based on the characteristics of the overmoded slow-wave device. The experiments were carried out at the Spark-2 accelerator. Under the condition of guiding magnetic field strength of 0.55 T, diode voltage of 474 k V,and beam current of 5.2kA, a microwave was generated with power of 510MW, mode of TM01, and frequency of 9.54 GHz. The relative half-width of the frequency spectrum is less than 1%, and the beam-to-microwave efficiency is about 21% in our experiments.

  10. 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.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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)

  13. Suppression of the fast and slow modulated waves mixing in the coupled nonlinear discrete LC transmission lines

    International Nuclear Information System (INIS)

    The conditions of propagation of fast and slow-modes of modulated waves on the two coupled discrete nonlinear LC transmission lines are examined, each line of the network containing a finite number of cells. It is found that the use of an appropriate unit-cell, a band-pass filter, associated to a convenient choice of the intermediate coupling capacitor between the two lines allows to avoid the crucial problem of mixing of waves of different modes in the network. Good qualitative and quantitative agreements are found between analytical predictions and numerical results. (author)

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

    OpenAIRE

    Ribeiro Sidarta; Gervasoni Damien; Soares Ernesto S; Zhou Yi; Lin Shih-Chieh; Pantoja Janaina; Lavine Michael; Nicolelis Miguel A. L

    2004-01-01

    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 ...

  15. A highly efficient CMOS nanoplasmonic crystal enhanced slow-wave thermal emitter improves infrared gas-sensing devices

    OpenAIRE

    Andreas Pusch; Andrea De Luca; Oh, Sang S.; Sebastian Wuestner; Tyler Roschuk; Yiguo Chen; Sophie Boual; Zeeshan Ali; Phillips, Chris C.; Minghui Hong; Maier, Stefan A.; Florin Udrea; Hopper, Richard H.; Ortwin Hess

    2015-01-01

    The application of plasmonics to thermal emitters is generally assisted by absorptive losses in the metal because Kirchhoff’s law prescribes that only good absorbers make good thermal emitters. Based on a designed plasmonic crystal and exploiting a slow-wave lattice resonance and spontaneous thermal plasmon emission, we engineer a tungsten-based thermal emitter, fabricated in an industrial CMOS process, and demonstrate its markedly improved practical use in a prototype non-dispersive infrared...

  16. Involvement of Spindles in Memory Consolidation Is Slow Wave Sleep-Specific

    Science.gov (United States)

    Cox, Roy; Hofman, Winni F.; Talamini, Lucia M.

    2012-01-01

    Both sleep spindles and slow oscillations have been implicated in sleep-dependent memory consolidation. Whereas spindles occur during both light and deep sleep, slow oscillations are restricted to deep sleep, raising the possibility of greater consolidation-related spindle involvement during deep sleep. We assessed declarative memory retention…

  17. Study on spontaneous bursts of high voltage slow wave activities in electroencephalograms of the aged

    International Nuclear Information System (INIS)

    100 EEGs with bursts of high voltage slow wave activities (bursts) were found in 1150 of aged subjects sixty years and over. In these cases computerized cranial tomography (CT) examinations were carried out within 60 days of EEG recordings and CT findings (bursts CTs) were compared with those of 100 cases without bursts (control CTs). Another 100 consecutive CTs of cases with matched the age and the disease were used as the control. The results were as follows: 1) In bursts CTs, the incidence of normal findings was only 7%, while it was 18% in control CTs. The difference was statistically significant (p<0.001). 2) Brain atrophy was remarkable in bursts CTs. In bursts CT, the incidence of brain atrophy showed more than minor degree was 89%, while it was 64% in control CTs. The difference was statistically significant (p<0.001). 3) The incidences of periventricular lucency (PVL), enlargement of the inferior and posterior horn of the lateral ventricle, basal ganglia calcification observed on CT were significantly higher (55%, 39%, 12%) in bursts CTs than in control CTs (p<0.01, p<0.01, p<0.05). 4) The incidence of focal lesions was lower in bursts CTs than in control CTs. In paticular, large lesions were recognized in only 3% of bursts CTs, whereas those were noted in 15% of control CTs. The difference was statistically significant (p<0.01). 5) Small lesions were recognized in 21% of neurological normal patients with bursts, while they were found in 5% of these of control CTs. 6) Frontal and thalamic lesions were found more frequently in bursts CTs (26%, 13%) than in control CTs (21%, 8%), but the difference was not statistically significant. 7) The correlation between the side showing high voltage of bursts and the side with lesions observed on CT was good. In this way, it may be conceivable that appearance of bursts is not due to only focal lesions but results from generalized brain disfunction, such as aging and others. (author)

  18. High-contrast 40 Gb/s operation of a 500 μm long silicon carrier-depletion slow wave modulator.

    Science.gov (United States)

    Brimont, A; Thomson, D J; Gardes, F Y; Fedeli, J M; Reed, G T; Martí, J; Sanchis, P

    2012-09-01

    In this Letter, we demonstrate a highly efficient, compact, high-contrast and low-loss silicon slow wave modulator based on a traveling-wave Mach-Zehnder interferometer with two 500 μm long slow wave phase shifters. 40  Gb/s operation with 6.6 dB extinction ratio at quadrature and with an on-chip insertion loss of only 6 dB is shown. These results confirm the benefits of slow light as a means to enhance the performance of silicon modulators based on the plasma dispersion effect. PMID:22940930

  19. Reflection Of Propagating Slow Magneto-acoustic Waves In Hot Coronal Loops : Multi-instrument Observations and Numerical Modelling

    CERN Document Server

    Mandal, Sudip; Fang, Xia; Banerjee, Dipankar; Pant, Vaibhav; Van Doorsselaere, Tom

    2016-01-01

    Slow MHD waves are important tools for understanding the coronal structures and dynamics. In this paper, we report a number of observations, from X-Ray Telescope (XRT) on board HINODE and SDO/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 the temperature of the loop plasma by performing DEM analysis on the AIA image sequence. The estimated speed of propagation is comparable or lower than the local sound speed suggesting it to be a propagating slow wave. The intensity perturbation amplitudes, 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 observati...

  20. Evidence of thermal conduction suppression in a solar flaring loop by coronal seismology of slow-mode waves

    CERN Document Server

    Wang, Tongjiang; Sun, Xudong; Provornikova, Elena; Davila, Joseph M

    2015-01-01

    Analysis of a longitudinal wave event observed by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) is presented. A time sequence of 131 A 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 min and a decay time of ~9 min. The measured phase speed of 500$\\pm$50 km/s matches the sound speed in the heated loop of ~10 MK, confirming that the observed waves are of slow mode. We derive the time-dependent temperature and electron density wave signals from six AIA extreme-ultraviolet (EUV) channels, and find that they are nearly in phase.The measured polytropic index from the temperature and density perturbations is 1.64$\\pm$0.08 close to the adiabatic index ...

  1. High-contrast 40 Gb/s operation of a 500 um long silicon carrier-depletion slow wave modulator

    OpenAIRE

    Brimont, Antoine Christian Jacques; Martí Sendra, Javier; Sanchis Kilders, Pablo; Thomson, D.J.; Gardes, F. Y.; Fedeli, J.M.; G. T. Reed

    2012-01-01

    This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.37.003504. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law In this Letter, we demonstrate a highly efficient, compact, high-contrast and low-loss silicon slow wave modulator ...

  2. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Ju Jiahua; Lu Weijuan

    2014-01-01

    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 follow-up 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 signiifcantly, 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.

  4. SMALL-SCALE PRESSURE-BALANCED STRUCTURES DRIVEN BY OBLIQUE SLOW MODE WAVES MEASURED IN THE SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    Yao Shuo [School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing 100083 (China); He, J.-S.; Tu, C.-Y.; Wang, L.-H. [Department of Geophysics, Peking University, Beijing (China); Marsch, E., E-mail: yaoshuo@cugb.edu.cn [Christian Albrechts University at Kiel, Kiel (Germany)

    2013-09-01

    Recently, small-scale pressure-balanced structures (PBSs) were identified in the solar wind, but their formation mechanism remains unclear. This work aims to reveal the dependence of the properties of small-scale PBSs on the background magnetic field (B{sub 0}) direction and thus to corroborate the in situ mechanism that forms them. We analyze the plasma and magnetic field data obtained by WIND in the quiet solar wind at 1 AU. First, we use a developed moving-average method to obtain B{sub 0}(s, t) for every temporal scale (s) at each time moment (t). By wavelet cross-coherence analysis, we obtain the correlation coefficients between the thermal pressure P{sub th} and the magnetic pressure P{sub B}, distributing against the temporal scale and the angle {theta}{sub xB} between B{sub 0}(s, t) and Geocentric Solar Ecliptic coordinates (GSE)-x. We note that the angle coverage of a PBS decreases with shorter temporal scale, but the occurrence of the PBSs is independent of {theta}{sub xB}. Suspecting that the isolated small PBSs are formed by compressive waves in situ, we continue this study by testing the wave modes forming a small-scale PBS with B{sub 0}(s, t) quasi-parallel to GSE-x. As a result, we identify that the cross-helicity and the compressibility attain values for a slow mode from theoretical calculations. The wave vector is derived from minimum variance analysis. Besides, the proton temperatures obey T < T{sub Parallel-To} derived from the velocity distribution functions, excluding a mirror mode, which is the other candidate for the formation of PBSs in situ. Thus, a small-scale PBS is shown to be driven by oblique, slow-mode waves in the solar wind.

  5. SMALL-SCALE PRESSURE-BALANCED STRUCTURES DRIVEN BY OBLIQUE SLOW MODE WAVES MEASURED IN THE SOLAR WIND

    International Nuclear Information System (INIS)

    Recently, small-scale pressure-balanced structures (PBSs) were identified in the solar wind, but their formation mechanism remains unclear. This work aims to reveal the dependence of the properties of small-scale PBSs on the background magnetic field (B0) direction and thus to corroborate the in situ mechanism that forms them. We analyze the plasma and magnetic field data obtained by WIND in the quiet solar wind at 1 AU. First, we use a developed moving-average method to obtain B0(s, t) for every temporal scale (s) at each time moment (t). By wavelet cross-coherence analysis, we obtain the correlation coefficients between the thermal pressure Pth and the magnetic pressure PB, distributing against the temporal scale and the angle θxB between B0(s, t) and Geocentric Solar Ecliptic coordinates (GSE)-x. We note that the angle coverage of a PBS decreases with shorter temporal scale, but the occurrence of the PBSs is independent of θxB. Suspecting that the isolated small PBSs are formed by compressive waves in situ, we continue this study by testing the wave modes forming a small-scale PBS with B0(s, t) quasi-parallel to GSE-x. As a result, we identify that the cross-helicity and the compressibility attain values for a slow mode from theoretical calculations. The wave vector is derived from minimum variance analysis. Besides, the proton temperatures obey T ∥ derived from the velocity distribution functions, excluding a mirror mode, which is the other candidate for the formation of PBSs in situ. Thus, a small-scale PBS is shown to be driven by oblique, slow-mode waves in the solar wind

  6. Slow and fast surface electromagnetic waves in planar structures contained left-handed material

    International Nuclear Information System (INIS)

    It was studied the properties of electromagnetic surface waves in left-handed material slab bounded by two semi-infinite nonmagnetic media with frequency dependent positive permittivity. It was assumed that all these media are isotropic and non-dissipative. It was shown that the phase velocities of waves are greater than the speed of light, and the group velocities are zero or negative

  7. Odors enhance slow-wave activity in non-rapid eye movement sleep.

    Science.gov (United States)

    Perl, Ofer; Arzi, Anat; Sela, Lee; Secundo, Lavi; Holtzman, Yael; Samnon, Perry; Oksenberg, Arie; Sobel, Noam; Hairston, Ilana S

    2016-05-01

    Most forms of suprathreshold sensory stimulation perturb sleep. In contrast, presentation of pure olfactory or mild trigeminal odorants does not lead to behavioral or physiological arousal. In fact, some odors promote objective and subjective measures of sleep quality in humans and rodents. The brain mechanisms underlying these sleep-protective properties of olfaction remain unclear. Slow oscillations in the electroencephalogram (EEG) are a marker of deep sleep, and K complexes (KCs) are an EEG marker of cortical response to sensory interference. We therefore hypothesized that odorants presented during sleep will increase power in slow EEG oscillations. Moreover, given that odorants do not drive sleep interruption, we hypothesized that unlike other sensory stimuli odorants would not drive KCs. To test these hypotheses we used polysomnography to measure sleep in 34 healthy subjects (19 women, 15 men; mean age 26.5 ± 2.5 yr) who were repeatedly presented with odor stimuli via a computer-controlled air-dilution olfactometer over the course of a single night. Each participant was exposed to one of four odorants, lavender oil (n = 13), vetiver oil (n = 5), vanillin (n = 12), or ammonium sulfide (n = 4), for durations of 5, 10, and 20 s every 9-15 min. Consistent with our hypotheses, we found that odor presentation during sleep enhanced the power of delta (0.5-4 Hz) and slow spindle (9-12 Hz) frequencies during non-rapid eye movement sleep. The increase was proportionate to odor duration. In addition, odor presentation did not modulate the occurrence of KCs. These findings imply a sleep-promoting olfactory mechanism that may deepen sleep through driving increased slow-frequency oscillations. PMID:26888107

  8. Catch the dream Wave : Propagation of Cortical Slow Oscillation to the Striatum in anaesthetised mice

    OpenAIRE

    Ferreira, Tiago

    2014-01-01

    Under anaesthesia or in deep sleep, different parts of the brain have a distinctive slow oscillatory activity, characterised by states of high membrane potential and intensive spiking activity, the Up-states; followed by hyperpolarisation and quiescence, the Down-states. This activity has been previously described in vitro and in vivo in the cortex and the striatum, across several species. Here, we look into it, during anaesthesia, in the mouse brain. Using whole-cell patch-clamp recordings o...

  9. Neuropsychological impairment in early-onset hydrocephalus and epilepsy with continuous spike-waves during slow-wave sleep: A case report and literature review

    Directory of Open Access Journals (Sweden)

    Annio Posar

    2013-01-01

    Full Text Available Epilepsy with continuous spike-waves during slow-wave sleep (CSWS is often characterized by a severe cognitive and behavioral impairment. Symptomatic cases also include patients with an early-onset hydrocephalus, but in literature detailed neuropsychological data on these subjects are not available. We describe the results of serial cognitive assessments in a girl with shunted early-onset hydrocephalus, followed by partial epilepsy complicated with CSWS at 4 years 10 months, in which a dramatic cognitive and behavioral deterioration occurred few months after CSWS onset. Adrenocorticotropic hormone treatment improved both clinical and electroencephalogram picture, but an impairment of visual perception, visual-motor coordination and executive functions persisted after CSWS disappearance. We hypothesize, in this case, an involvement of right occipital-parietal lobe and prefrontal lobe.

  10. Automatic detection of slow-wave sleep and REM-sleep stages using polysomnographic ECG signals

    International Nuclear Information System (INIS)

    We describe in this paper a new approach of classifying the different sleep stages only by focusing on the polysomnographic ECG signals. We show the pre-processing technique of the ECG signals. At the same time the identifcation and elimination of the different types of artifacts which contain the signal and its reconstruction are shown. The automatic classification of the slow-deep sleep and the rapid eye movement sleep called in this work REM-sleep consists in extracting physiological indicators that characterize these two sleep stages through the polysomnographic ECG signal. In other words, this classification is based on the analysis of the cardiac rhythm during a night's sleep.

  11. Research on the Characteristic of the Disk-Loaded Waveguide, Rib-Loaded Disk-Loaded Waveguide and Helix Slow-Wave Structures

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong

    2005-01-01

    @@ The fast development of modern electronic warfare, broadband high power array radar system, high power jammer and microwave directional power weapon imposes high demand on high power microwave resource. With such features as high power, broadband, multi-mode, etc., traveling wave tubes (TWTs) play an important role in the high power microwave amplifiers. Since the slow-wave system is the core of beam-wave interaction in TWTs, the function and performance of it directly determine the capability of the TWTs.

  12. Site Response And Slow Basin Waves In The Sacramento/San Joaquin Delta

    Science.gov (United States)

    Fletcher, J. B.; Sell, R.

    2009-12-01

    About 1700 km of levees protect farmland and communities from inundation in the delta of the Sacramento/San Joaquin Rivers at the western edge of the Great Valley in California. These levees are made from dredged soils, such as peat, and are characterized by low shear-wave velocities (about 200m/s) and are vulnerable to breaking from major earthquakes in the greater San Francisco Bay area. We have investigated the seismic response of sites in the delta by deploying a set of broadband seismometers to record local moderate-sized earthquakes. Each of the 11 sites has a 30s broadband, 3-component seismograph digitized continuously at 100 sps/channel. In the summer of 2008 we expanded the original array, which covered a small area near Bethel Is., to cover a greater proportion of the delta, and it now extends from Tracy in the south to Bethel Is. in the northwest to Eight Mile Road in the northeast, an area of about 20 by 30 km. Several of the sites are on levees and the others are on farmland. One site is on a outcrop just west of the Clifton Court Forebay in the foothills. During the last year we have recorded nine events in the M 3 to 4 range with good signal to noise at the array. Site response was estimated with spectral ratios of S waves using Black Diamond Mine, a station in the UC Berkeley seismic network, as a reference station. Site responses at levee sites typically show large resonances in the 1-3 Hz range with amplifications greater than 10 for the Sept. 6, 2008 M4.1 Alamo event. Other sites show amplifications between 2 and 7 at various frequencies between 1 and 10 Hz. Sites within the delta show late-arriving Rayleigh waves with a period of about one second. A three-element array at the Holland Marina (spacing 180-290m) shows these waves to be traveling at about 610 m/s with a back azimuth about 20 degrees off the azimuth to the epicenter. Observations of well-developed, one-second surface waves across basins are not common, but they are similar to

  13. On the properties of slow mhd sausage waves within small-scale photospheric magnetic structures

    CERN Document Server

    Freij, N; Morton, R J; Ruderman, M S; Karlovsky, V; Erdekyi, R

    2015-01-01

    The presence of magneto-acoustic waves in magnetic structures in the solar atmosphere is well-documented. Applying the technique of solar magneto-seismology (SMS) allows us to infer the background properties of these structures. Here, we aim to identify properties of the observed magneto-acoustic waves and study the background properties of magnetic structures within the lower solar atmosphere. Using the Dutch Open Telescope (DOT) and Rapid Oscillations in the Solar Atmosphere (ROSA) instruments, we captured two series of high-resolution intensity images with short cadence of two isolated magnetic pores. Combining wavelet analysis and empirical mode decomposition (EMD), we determined characteristic periods within the cross-sectional (i.e., area) and intensity time series. Then, by applying the theory of linear magnetohydrodynamics (MHD), we identified the mode of these oscillations within the MHD framework. Several oscillations have been detected within these two magnetic pores. Their periods range from 3 to ...

  14. Slow modulations of periodic waves in Hamiltonian PDEs, with application to capillary fluids

    OpenAIRE

    Benzoni-Gavage, Sylvie; Noble, Pascal; Rodrigues, Luis Miguel

    2014-01-01

    Since its elaboration by Whitham, almost fifty years ago, modulation theory has been known to be closely related to the stability of periodic traveling waves. However, it is only recently that this relationship has been elucidated, and that fully nonlinear results have been obtained. These only concern dissipative systems though: reaction-diffusion systems were first considered by Doelman, Sandstede, Scheel, and Schneider [Mem. Amer. Math. Soc. 2009], and viscous systems of conservation laws ...

  15. Ion thermal effects on slow mode solitary waves in plasmas with two adiabatic ion species

    Energy Technology Data Exchange (ETDEWEB)

    Nsengiyumva, F., E-mail: franco.nseng@gmail.com; Hellberg, M. A., E-mail: hellberg@ukzn.ac.za; Mace, R. L., E-mail: macer@ukzn.ac.za [School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000 (South Africa)

    2015-09-15

    Using both the Sagdeev and Korteweg-de Vries (KdV) methods, ion thermal effects on slow mode ion acoustic solitons and double layers are investigated in a plasma with two adiabatic positive ion species. It is found that reducing the gap between the two ion thermal speeds by increasing the relative temperature of the cool ions increases the typical soliton/double layer speeds for all values of the ion-ion density ratio and reduces the range in the density ratio that supports double layers. The effect of increasing the relative cool ion temperature on the soliton/double layer amplitudes depends on the relative densities. For lower values of the ion density ratio, an increase in cool ion temperature leads to a significant decrease in soliton/double layer amplitude, so one may find that solitons of all permissible speeds lie within the range of KdV theory.

  16. Ion thermal effects on slow mode solitary waves in plasmas with two adiabatic ion species

    International Nuclear Information System (INIS)

    Using both the Sagdeev and Korteweg-de Vries (KdV) methods, ion thermal effects on slow mode ion acoustic solitons and double layers are investigated in a plasma with two adiabatic positive ion species. It is found that reducing the gap between the two ion thermal speeds by increasing the relative temperature of the cool ions increases the typical soliton/double layer speeds for all values of the ion-ion density ratio and reduces the range in the density ratio that supports double layers. The effect of increasing the relative cool ion temperature on the soliton/double layer amplitudes depends on the relative densities. For lower values of the ion density ratio, an increase in cool ion temperature leads to a significant decrease in soliton/double layer amplitude, so one may find that solitons of all permissible speeds lie within the range of KdV theory

  17. Characterization of K-complexes and slow wave activity in a neural mass model.

    Directory of Open Access Journals (Sweden)

    Arne Weigenand

    2014-11-01

    Full Text Available NREM sleep is characterized by two hallmarks, namely K-complexes (KCs during sleep stage N2 and cortical slow oscillations (SOs during sleep stage N3. While the underlying dynamics on the neuronal level is well known and can be easily measured, the resulting behavior on the macroscopic population level remains unclear. On the basis of an extended neural mass model of the cortex, we suggest a new interpretation of the mechanisms responsible for the generation of KCs and SOs. As the cortex transitions from wake to deep sleep, in our model it approaches an oscillatory regime via a Hopf bifurcation. Importantly, there is a canard phenomenon arising from a homoclinic bifurcation, whose orbit determines the shape of large amplitude SOs. A KC corresponds to a single excursion along the homoclinic orbit, while SOs are noise-driven oscillations around a stable focus. The model generates both time series and spectra that strikingly resemble real electroencephalogram data and points out possible differences between the different stages of natural sleep.

  18. Dispersive characteristics and longitudinal resonance properties in a relativistic backward wave oscillator with the coaxial arbitrary-profile slow-wave structure

    International Nuclear Information System (INIS)

    The method for calculating the dispersion relations of the slow-wave structures (SWSs) with arbitrary geometrical structures is studied in detail by using the Fourier series expansion. In addition, dispersive characteristics and longitudinal resonance properties of the SWSs with the cosinusoidal, trapezoidal, and rectangular corrugations are analyzed by numerical calculation. Based on the above discussion, a comparison on an L-band coaxial relativistic backward wave oscillator (BWO) and an L-band coaxial BWO with a coaxial extractor is investigated in detail with particle-in-cell KARAT code (V. P. Tarakanov, Berkeley Research Associates, Inc., 1992). Furthermore, experiments are carried out at the TORCH-01 accelerator under the low guiding magnetic field. At diode voltage of 647 kV, beam current of 9.3 kA, and guiding magnetic field strength of 0.75 T, the microwave is generated with power of 1.07 GW, mode of TM01, and frequency of 1.61 GHz. That is the first experimental report of the L-band BWO.

  19. Dispersive characteristics and longitudinal resonance properties in a relativistic backward wave oscillator with the coaxial arbitrary-profile slow-wave structure

    Science.gov (United States)

    Ge, Xingjun; Zhong, Huihuang; Qian, Baoliang; Zhang, Jun; Fan, Yuwei; Shu, Ting; Liu, Jinliang

    2009-11-01

    The method for calculating the dispersion relations of the slow-wave structures (SWSs) with arbitrary geometrical structures is studied in detail by using the Fourier series expansion. In addition, dispersive characteristics and longitudinal resonance properties of the SWSs with the cosinusoidal, trapezoidal, and rectangular corrugations are analyzed by numerical calculation. Based on the above discussion, a comparison on an L-band coaxial relativistic backward wave oscillator (BWO) and an L-band coaxial BWO with a coaxial extractor is investigated in detail with particle-in-cell KARAT code (V. P. Tarakanov, Berkeley Research Associates, Inc., 1992). Furthermore, experiments are carried out at the TORCH-01 accelerator under the low guiding magnetic field. At diode voltage of 647 kV, beam current of 9.3 kA, and guiding magnetic field strength of 0.75 T, the microwave is generated with power of 1.07 GW, mode of TM01, and frequency of 1.61 GHz. That is the first experimental report of the L-band BWO.

  20. 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.

  1. Human longevity is associated with regular sleep patterns, maintenance of slow wave sleep and favorable lipid profile

    Directory of Open Access Journals (Sweden)

    Diego Robles Mazzotti

    2014-06-01

    Full Text Available Some individuals are able to successfully reach very old ages, reflecting higher adaptation against age-associated effects. Sleep is one of the processes deeply affected by aging; however few studies evaluating sleep in long-lived individuals (aged over 85 have been reported to date. The aim of this study was to characterize the sleep patterns and biochemical profile of oldest old individuals (N=10, age 85-105 years old and compare them to young adults (N=15, age 20-30 years old and older adults (N=13, age 60-70 years old. All subjects underwent full-night polysomnography, one-week of actigraphic recording and peripheral blood collection. Sleep electroencephalogram spectral analysis was also performed. The oldest old individuals showed lower sleep efficiency and REM sleep when compared to the older adults, while stage N3 percentage and delta power were similar across the groups. Oldest old individuals maintained strictly regular sleep-wake schedules and also presented higher HDL-cholesterol and lower triglyceride levels than older adults. The present study revealed novel data regarding specific sleep patterns and maintenance of slow wave sleep in the oldest old group. Taken together with the favorable lipid profile, these results contribute with evidence to the importance of sleep and lipid metabolism regulation in the maintenance of longevity in humans.

  2. Spectroscopic Observations of Propagating Disturbances in a Polar Coronal Hole: Evidence of Slow Magneto-acoustic Waves

    CERN Document Server

    Gupta, G R; Marsch, E; Solanki, S K; Banerjee, D

    2012-01-01

    We focus on detecting and studying quasi-periodic propagating features that have been interpreted both in terms of slow magneto-acoustic waves and of high speed upflows. We analyze long duration spectroscopic observations of the on-disk part of the south polar coronal hole taken on 1997 February 25 by the SUMER spectrometer aboard SOHO. We calibrated the velocity with respect to the off-limb region and obtain time--distance maps in intensity, Doppler velocity and line width. We also perform a cross correlation analysis on different time series curves at different latitudes. We study average spectral line profiles at the roots of propagating disturbances and along the propagating ridges, and perform a red-blue asymmetry analysis. We find the clear presence of propagating disturbances in intensity and Doppler velocity with a projected propagation speed of about $60\\pm 4.8$ km s$^{-1}$ and a periodicity of $\\approx$14.5 min. To our knowledge, this is the first simultaneous detection of propagating disturbances i...

  3. EDITORIAL: Slow light Slow light

    Science.gov (United States)

    Boyd, Robert; Hess, Ortwin; Denz, Cornelia; Paspalakis, Emmanuel

    2010-10-01

    Research into slow light began theoretically in 1880 with the paper [1] of H A Lorentz, who is best known for his work on relativity and the speed of light. Experimental work started some 60 years later with the work of S L McCall and E L Hahn [2] who explored non-linear self-induced transparency in ruby. This field of research has burgeoned in the last 10 years, starting with the work of L Vestergaard Hau and coworkers on slow light via electromagnetically induced transparency in a Bose-Einstein condensate [3]. Many groups are now able to slow light down to a few metres per second or even stop the motion of light entirely [4]. Today, slow light - or more often `slow and fast light' - has become its own vibrant field with a strongly increasing number of publications. In broad scope, slow light research can be categorized in terms of the sort of physical mechanism used to slow down the light. One sort of slow light makes use of material dispersion. This dispersion can be the natural dispersion of the ordinary refractive index or can be the frequency dependence of some nonlinear optical process, such as electromagnetically induced transparency, coherent population oscillations, stimulated light scattering, or four-wave mixing processes. The second sort of slow light makes use of the wavelength dependence of artificially structured materials, such as photonic crystals, optical waveguides, and collections of microresonators. Material systems in which slow light has been observed include metal vapours, rare-earth-doped materials, Raman and Brillioun gain media, photonic crystals, microresonators and, more recently, metamaterials. A common feature of all of these schemes is the presence of a sharp single resonance or multiple resonances produced by an atomic transition, a resonance in a photonic structure, or in a nonlinear optical process. Current applications of slow light include a series of attractive topics in optical information processing, such as optical data

  4. Bowel incontinence

    Science.gov (United States)

    ... move well enough to safely get to the bathroom on their own. These people need special care. They may become used to not getting to the toilet when it's time to have a bowel movement. To ... the bathroom is safe and comfortable. Using special pads or ...

  5. Differential Functional Roles of Slow-Wave and Oscillatory-Alpha Activity in Visual Sensory Cortex during Anticipatory Visual–Spatial Attention

    OpenAIRE

    Grent-'t-Jong, Tineke; Boehler, C. Nicolas; Kenemans, J Leon; Woldorff, Marty G.

    2011-01-01

    Markers of preparatory visual–spatial attention in sensory cortex have been described both as lateralized, slow-wave event-related potential (ERP) components and as lateralized changes in oscillatory-electroencephalography alpha power, but the roles of these markers and their functional relationship are still unclear. Here, 3 versions of a visual–spatial cueing paradigm, differing in perceptual task difficulty and/or response instructions, were used to investigate the functional relationships...

  6. Exposure to extinction-associated contextual tone during slow-wave sleep and wakefulness differentially modulates fear expression.

    Science.gov (United States)

    Ai, Si-Zhi; Chen, Jie; Liu, Jian-Feng; He, Jia; Xue, Yan-Xue; Bao, Yan-Ping; Han, Fang; Tang, Xiang-Dong; Lu, Lin; Shi, Jie

    2015-09-01

    Recent research has used context cues (odor or auditory cues) to target memories during sleep and has demonstrated that they can enhance declarative and procedural memories. However, the effects of external cues re-presented during sleep on emotional memory are still not fully understood. In the present study, we conducted a Pavlovian fear conditioning/extinction paradigm and examined the effects of re-exposure to extinction memory associated contextual tones during slow-wave sleep (SWS) and wakefulness on fear expression. The participants underwent fear conditioning on the first day, during which colored squares served as the conditioned stimulus (CS) and a mild shock served as the unconditioned stimulus (US). The next day, they underwent extinction, during which the CSs were presented without the US but accompanied by a contextual tone (pink noise). Immediately after extinction, the participants were required to take a nap or remain awake and randomly assigned to six groups. Four of the groups were separately exposed to the associated tone (i.e. SWS-Tone group and Wake-Tone group) or an irrelevant tone (control tone, CtrT) (i.e. SWS-CtrT group and Wake-CtrT group), while the other two groups were not (i.e. SWS-No Tone group and Wake-No Tone group). Subsequently, the conditioned responses to the CSs were tested to evaluate the fear expression. All of the participants included in the final analysis showed successful levels of fear conditioning and extinction. During the recall test, the fear responses were significantly higher in the SWS-Tone group than that in the SWS-No Tone group or the SWS-CtrT group, while the Wake-Tone group exhibited more attenuated fear responses than either the Wake-No Tone group or Wake-CtrT group. Otherwise, re-exposure to auditory tones during SWS did not affect sleep profiles. These results suggest that distinct conditions during which re-exposure to an extinction memory associated contextual cue contributes to differential effects on

  7. Morning and evening-type differences in slow waves during NREM sleep reveal both trait and state-dependent phenotypes.

    Directory of Open Access Journals (Sweden)

    Valérie Mongrain

    Full Text Available Brain recovery after prolonged wakefulness is characterized by increased density, amplitude and slope of slow waves (SW, <4 Hz during non-rapid eye movement (NREM sleep. These SW comprise a negative phase, during which cortical neurons are mostly silent, and a positive phase, in which most neurons fire intensively. Previous work showed, using EEG spectral analysis as an index of cortical synchrony, that Morning-types (M-types present faster dynamics of sleep pressure than Evening-types (E-types. We thus hypothesized that single SW properties will also show larger changes in M-types than in E-types in response to increased sleep pressure. SW density (number per minute and characteristics (amplitude, slope between negative and positive peaks, frequency and duration of negative and positive phases were compared between chronotypes for a baseline sleep episode (BL and for recovery sleep (REC after two nights of sleep fragmentation. While SW density did not differ between chronotypes, M-types showed higher SW amplitude and steeper slope than E-types, especially during REC. SW properties were also averaged for 3 NREM sleep periods selected for their decreasing level of sleep pressure (first cycle of REC [REC1], first cycle of BL [BL1] and fourth cycle of BL [BL4]. Slope was significantly steeper in M-types than in E-types in REC1 and BL1. SW frequency was consistently higher and duration of positive and negative phases constantly shorter in M-types than in E-types. Our data reveal that specific properties of cortical synchrony during sleep differ between M-types and E-types, although chronotypes show a similar capacity to generate SW. These differences may involve 1 stable trait characteristics independent of sleep pressure (i.e., frequency and durations likely linked to the length of silent and burst-firing phases of individual neurons, and 2 specific responses to increased sleep pressure (i.e., slope and amplitude expected to depend on the synchrony

  8. Dissociating the contributions of slow-wave sleep and rapid eye movement sleep to emotional item and source memory.

    Science.gov (United States)

    Groch, S; Zinke, K; Wilhelm, I; Born, J

    2015-07-01

    Sleep benefits the consolidation of emotional memories, and this influence is commonly attributed to the rapid eye movement (REM) stage of sleep. However, the contributions of sleep stages to memory for an emotional episode may differ for the event per se (i.e., item memory), and the context in which it occurred (source memory). Here, we examined the effects of slow wave sleep (SWS) and REM sleep on the consolidation of emotionally negative and neutral item (picture recognition) and source memory (recall of picture-location and picture-frame color association) in humans. In Study 1, the participants (n=18) learned 48 negative and 48 neutral pictures which were presented at specific locations and preceded by colored frames that had to be associated with the picture. In a within-subject design, learning was either followed by a 3-h early-night SWS-rich or by a late-night REM sleep-rich retention interval, then retrieval was tested. Only after REM-rich sleep, and not after SWS-rich sleep, was there a significant emotional enhancement, i.e., a significantly superior retention of emotional over neutral pictures. On the other hand, after SWS-rich sleep the retention of picture-frame color associations was better than after REM-rich sleep. However, this benefit was observed only for neutral pictures; and it was completely absent for the emotional pictures. To examine whether this absent benefit reflected a suppressive effect of emotionality on associations of minor task relevance, in Study 2 we manipulated the relevance of the picture-frame color association by combining it with information about monetary reward, following otherwise comparable procedures. Here, rewarded picture-frame color associations were equally well retained over SWS-rich early sleep no matter if the frames were associated with emotional or neutral pictures. Results are consistent with the view that REM sleep favors the emotional enhancement of item memory whereas SWS appears to contribute primarily

  9. Experimental study of resonant excitation of slow low-frequency waves in a plasma by colliding electron beams

    International Nuclear Information System (INIS)

    The excitation of space charge waves in a double beam-plasma system, the mechanism of expulsion of the plasma by the ponderomotive force of the high frequency (HF) oscillations and also the excitation of ion-sound oscillations as a result of mixing of the space charge waves are studied. In the case of mode merging, a strong displacement of the plasma in the region of maximum density of the HF oscillations (deltan/n approximately 0.9) occurs. Intense ion-sound waves are then eXcited, their amplitudes being sufficient for capture and acceleration of the plasma ions

  10. Simultaneous guiding of slow elastic and light waves in three-dimensional topology-type phoxonic crystals with a line defect

    International Nuclear Information System (INIS)

    Phoxonic crystals (PXCs) which exhibit simultaneous phononic and photonic bandgaps are promising artificial materials for optomechanical and acousto-optical devices. In this paper, we theoretically investigate the phononic and photonic guided modes in the three-dimensional topology-type PXCs with a line defect. By varying the geometrical parameters, simultaneous guidance of the slow elastic and light (electromagnetic) waves can be realized. Both elastic and optical energies can be highly confined in and near the defect region. Small elastic and optical group velocities with small group velocity dispersions can be achieved. The group velocities are about 10 and 20 times smaller than the transverse velocity of the elastic waves in silicon and the speed of light in vacuum, respectively. (paper)

  11. A Method of Fitting Function to Extract Phase Slowness of Dispersive Wave from Sonic Logging Data%一种提取声波测井频散波相慢度的适应函数方法

    Institute of Scientific and Technical Information of China (English)

    孙志峰; 樊官民; 孟杰

    2011-01-01

    提出了一种对声波测井频散波数据频散校正的适应函数方法.通过提取频散波的频率慢度相关图,得到频散波的频散曲线,由频散曲线在慢度轴上的投影可得到关于地层波慢度的统计直方图.构造一种适应函数与直方图进行非线性最小二乘拟合,得到与统计直方图最优匹配的适应函数,这个适应函数起始点对应的慢度即为真实的地层波慢度.给出了采用该方法处理理论模拟的偶板子波及现场实测的偶板子波资料的例子.对理论模拟的偶板子波处理,计算的偶极子波慢度值与地层真实横波慢度基本一致;对现场实测的偶板子波数据处理,计算的偶极子波慢度与频率慢度投影曲线相匹配.处理结果表明,采用该方法对频散波进行频散校正是可靠有效的.%The authors present a method to extract the phase slowness from dispersive waves provided by sonic logging. The dispersion curve can be acquired by maximizing the frequency-slowness coherence value at each frequency. The projection of dispersion curve on slowness axis is the histogram of formation slowness. The method is based on matching a fitting function to the slowness histogram using method of nonlinear least squares. The slowness of edge location in the best fitting function is the true formation slowness. As an example, the method is employed to process both theoretical dipole wave and field sonic logging data. The phase slowness of dipole wave and the formation slowness are almost the same for theoretical dipole wave; the phase slowness of dipole wave matches with the curve of slowness-frequency projection for field sonic logging data. It is reliable and effective for processing dispersive wave data with this method.

  12. Large bowel resection - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100089.htm Large bowel resection - Series To use the sharing features ... 6 out of 6 Normal anatomy Overview The large bowel [large intestine or the colon] is part ...

  13. Large bowel resection - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000151.htm Large bowel resection - discharge To use the sharing features ... surgery to remove all or part of your large intestine (large bowel). You may also have had ...

  14. Large bowel resection

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002941.htm Large bowel resection To use the sharing features on this page, please enable JavaScript. Large bowel resection is surgery to remove all or ...

  15. Narcotic Bowel Syndrome

    Science.gov (United States)

    ... Intolerance Malabsorption Narcotic Bowel Syndrome Radiation Therapy Injury Short Bowel Syndrome Symptoms & Causes Treatments Nutrition and Diet Managing Secondary Effects Medications Surgery Daily Living with SBS Resources SMA Syndrome Volvulus ...

  16. 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.

  17. Impedance-based analysis and study of phase sensitivity in slow-wave two-beam accelerators

    International Nuclear Information System (INIS)

    This paper presents a new formalism which makes the analysis and understanding of both the relativistic klystron (RK) and the standing-wave free-electron laser (SWFEL) two-beam accelerator (TBA) available to a wide audience of accelerator physicists. A ''coupling impedance'' for both the RK and SWFEWL is introduced, which can include realistic cavity features, such as beam and vacuum ports, in a simple manner. The RK and SWFEL macroparticle equations, which govern the energy and phase evolution of successive bunches in the beam, are of identical form, differing only by multiplicative factors. Expressions are derived for the phase and amplitude sensitivities of the TBA schemes to errors (shot-to-shot jitter) in current and energy. The analysis allows, for the first time, relative comparisons of the RK and the SWFEL TBAs

  18. The Bowel Microbiota and Inflammatory Bowel Diseases

    Directory of Open Access Journals (Sweden)

    Gerald W. Tannock

    2010-01-01

    Full Text Available The human bowel contains a large and biodiverse bacterial community known as the microbiota or microbiome. It seems likely that the microbiota, fractions of the microbiota, or specific species comprising the microbiota provide the antigenic fuel that drives the chronic immune inflammation of the bowel mucosa that is characteristic of Crohn's disease and ulcerative colitis. At least twenty years of microbiological research have been expended on analysis of the composition of the bowel microbiota of inflammatory bowel disease patients in comparison to that of control subjects. Despite extensive speculations about the aetiological role of dysbiosis in inflammatory bowel diseases, knowledge that can be easily translated into effective remedies for patients has not eventuated. The causes of this failure may be due to poorly defined and executed bacteriological studies, as well as the overwhelming complexity of a biome that contains hundreds of bacterial species and trillions of bacterial cells.

  19. Amplitude inversion of fast and slow converted waves for fracture characterization of the Montney Formation in Pouce Coupe field, Alberta, Canada

    Science.gov (United States)

    MacFarlane, Tyler L.

    The Montney Formation of western Canada is one of the largest economically viable gas resource plays in North America with reserves of 449TCF. As an unconventional tight gas play, the well development costs are high due to the hydraulic stimulations necessary for economic success. The Pouce Coupe research project is a multidisciplinary collaboration between the Reservoir Characterization Project (RCP) and Talisman Energy Inc. with the objective of understanding the reservoir to enable the optimization of well placement and completion design. The work in this thesis focuses on identifying the natural fractures in the reservoir that act as the delivery systems for hydrocarbon flow to the wellbore. Characterization of the Montney Formation at Pouce Coupe is based on time-lapse multicomponent seismic surveys that were acquired before and after the hydraulic stimulation of two horizontal wells. Since shear-wave velocities and amplitudes of the PS-waves are known to be sensitive to near-vertical fractures, I utilize isotropic simultaneous seismic inversions on azimuthally-sectored PS1 and PS2 data sets to obtain measurements of the fast and slow shear-velocities. Specifically, I analyze two orthogonal azimuths that are parallel and perpendicular to the strike of the dominant fracture system in the field. These volumes are used to approximate the shear-wave splitting parameter (gamma(s*)) that is closely related to crack density. Since crack density has a significant impact on defining the percolation zone, the work presented in this thesis provides information that can be utilized to reduce uncertainty in the reservoirs fracture model. Isotropic AVO inversion of azimuthally limited PS-waves demonstrates sufficient sensitivity to detect contrast between the anisotropic elastic properties of the reservoir and is capable of identifying regions with high crack density. This is supported by integration with spinner production logs, hydraulic stimulation history of the field

  20. [Effectiveness of pinaverium bromide therapy on colonic motility disorders in irritable bowel syndrome].

    Science.gov (United States)

    Wittmann, T; Fehér, A; Rosztóczy, A; Jánosi, J

    1999-02-28

    The special patterns of the slow wave activity in irrittable bowel syndrome by means of surface electromyography were examined and the effect of pinaverium bromide on the symptoms and on the colonic motility in this disease was estimated. Twenty two patients with irritable bowel syndrome and 7 healthy controls were selected to the study. The clinical symptoms were abdominal pain and bloating in all patients, constipation in 9, and diarrhoea in 6 cases. Surface electromyography was carried out before and on the 14th day of the treatment with pinaverium bromide (50 mg t. i. d). The colonic motility was analysed in a 2 hour fasting and a 2 hour postprandial period following a standard (800 kCal) meal. The slow wave frequency of 0.01-0.04 Hz were selected and analysed. The mean frequency of activity peaks (n/10 min) and power-index (area under curve, microV 10 min) were measured. For statistical analysis Student's t-test was applied. Electromyogram of patients with irritable bowel syndrome showed a significant increase of the measured colonic motility parameters both in fasting and postprandial states. Fourteen days of pinaverium bromide treatment was able to significantly reduce the intensity of the colonic motor activity. Administration of pinaverium bromide completely released in 6 and significantly improved the abdominal pain in other 12 patients, while the bloating disappeared in 12 and was significantly improved in 5 from 22 patients. Pinaverium bromide was able to normalise the stool frequency: the weekly number of stools was decreased from 16 to 7 in the patients complaining diarrhoea ant it was increased from 2 to 6 in the patients with constipation. PMID:10204402

  1. Slow wave changes in amygdala to visual, auditory, and social stimuli following lesions of the inferior temporal cortex in squirrel monkey (Saimiri sciureus).

    Science.gov (United States)

    Kling, A S; Lloyd, R L; Perryman, K M

    1987-01-01

    Radiotelemetry of slow wave activity of the amygdala was recorded under a variety of conditions. Power, and the percentage of power in the delta band, increased in response to stimulation. Recordings of monkey vocalizations and slides of ethologically relevant, natural objects produced a greater increase in power than did control stimuli. The responses to auditory stimuli increased when these stimuli were presented in an unrestrained, group setting, yet the responses to the vocalizations remained greater than those following control stimuli. Both the natural auditory and visual stimuli produced a reliable hierarchy with regard to the magnitude of response. Following lesions of inferior temporal cortex, these two hierarchies are disrupted, especially in the auditory domain. Further, these same stimuli, when presented after the lesion, produced a decrease, rather than an increase, in power. Nevertheless, the power recorded from the natural stimuli was still greater than that recorded from control stimuli in that the former produced less of a decrease in power, following the lesion, than did the latter. These data, in conjunction with a parallel report on evoked potentials in the amygdala, before and after cortical lesions, lead us to conclude that sensory information, particularly auditory, available to the amygdala, following the lesion, is substantially the same, and that it is the interpretation of this information, by the amygdala, which is altered by the cortical lesion. PMID:3566692

  2. Ocular-motor profile and effects of memantine in a familial form of adult cerebellar ataxia with slow saccades and square wave saccadic intrusions.

    Directory of Open Access Journals (Sweden)

    Francesca Rosini

    Full Text Available Fixation instability due to saccadic intrusions is a feature of autosomal recessive spinocerebellar ataxias, and includes square wave intrusions (SWI and macrosaccadic oscillations (MSO. A recent report suggested that the non-competitive antagonist of NMDA receptors, memantine, could decrease MSO and improve fixation in patients with spinocerebellar ataxia with saccadic intrusions (SCASI. We similarly tested two sisters, respectively of 58 and 60 years, with an unrecognized form of recessive, adult-onset cerebellar ataxia, peripheral neuropathy and slow saccades, who showed prominent SWI and also complained with difficulty in reading. We tested horizontal visually guided saccades (10°-18° and three minutes of steady fixation in each patient and in thirty healthy controls. Both patients showed a significant reduction of peak and mean velocity compared with control subjects. Large SWI interrupting steady fixation were prominent during steady fixation and especially following visually guided saccades. Eye movements were recorded before and during the treatment with memantine, 20 mg/daily for 6 months. The treatment with memantine reduced both the magnitude and frequency of SWI (the former significantly, but did not modified neurological conditions or saccade parameters. Thus, our report suggests that memantine may have some general suppressive effect on saccadic intrusions, including both SWI and MSO, thereby restoring the capacity of reading and visual attention in these and in other recessive forms of ataxia, including Friedreich's, in which saccadic intrusions are prominent.

  3. Short bowel syndrome

    International Nuclear Information System (INIS)

    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.)

  4. Short Bowel Syndrome

    Science.gov (United States)

    ... may include nutritional support medications surgery intestinal transplant Nutritional Support The main treatment for short bowel syndrome is nutritional support, which may include the following: Oral rehydration. Adults ...

  5. Small Bowel Bleeding

    Science.gov (United States)

    ... ACG on Facebook About ACG ACG Store ACG Patient Education & Resource Center Home GI Health and Disease Recursos en Español What is a Gastroenterologist? Podcasts and Videos GI Health Centers Colorectal Cancer Hepatitis C Inflammatory Bowel Disease Irritable Bowel Syndrome Obesity © ...

  6. Fully Distributed Tunable Bandpass Filter Based on Ba0.5Sr0.5TiO3 Thin-Film Slow-Wave Structure

    Directory of Open Access Journals (Sweden)

    Sébastien L. Delprat

    2011-01-01

    Full Text Available This paper presents simulation and measurement results of fully distributed tunable coplanar bandpass filters (BPFs with center frequencies around 6 GHz that make use of ferroelectric Barium Strontium Titanate (BaxSr1−xTiO3 or BST-x thin film as tunable material. The two experimental bandpass filters tested are based on a novel frequency-agile structure composed of cascaded half wavelength slow-wave resonators (2 poles and three coupled interdigital capacitors (IDCs optimized for bias voltage application. Devices with gap dimensions of 10 and 3 μm are designed and fabricated with a two-step process on polycrystalline Ba0.5Sr0.5TiO3 thin films deposited on alumina substrate. A frequency tunability of 9% is obtained for the 10 μm gap structure at ±30 V with 7 dB insertion loss (the BST dielectric tunability being 26% with 0.04 loss tangent for this gap size. When the structure gap is reduced to 3 μm the center frequency shifts with a constant 9 dB insertion loss from 6.95 GHz at 0 V to 9.05 GHz at ±30 V, thus yielding a filter tunability of 30% (the BST dielectric tunability being 60% with 0.04 loss tangent for this gap size, a performance comparable to some extent to localized or lumped element BPFs operating at microwave frequency (>2 GHz.

  7. Hippocampal formation is involved in movement selection: evidence from medial septal cholinergic modulation and concurrent slow-wave (theta rhythm) recording.

    Science.gov (United States)

    Oddie, S D; Kirk, I J; Whishaw, I Q; Bland, B H

    1997-11-01

    Hippocampal rhythmical slow-wave field activity which occurs in response to sensory stimulation is predominantly cholinergic (atropine-sensitive theta rhythm), can precede movement initiation, and co-occurs during non-cholinergic theta rhythm associated with ongoing movement (atropine-resistant). This relationship suggests that theta rhythm plays some role in movement control. The present naturalistic experiments tested the idea that atropine-sensitive theta rhythm plays a role in sensory integration and planning required for initiating appropriate movements. One of a pair of hungry rats, the victim, implanted with hippocampal field recording electrodes, a septal injection cannula, and a posterior hypothalamic stimulating electrode, was given food which the other, the robber, tries to steal. Since the victim dodges from the robber with a latency, distance, and velocity dependent upon the size of the food, elapsed eating time, and proximity of the robber, the movement requires sensory integration and planning. Although eating behavior seemed normal, atropine-sensitive theta rhythm and dodging were disrupted by an infusion of a cholinergic antagonist into the medial septum. When the victim in turn attempted to steal the food back, Type 1 theta rhythm was present and robbery attempts seemed normal. Prior to cholinergic blockade, posterior hypothalamic stimulation produced theta rhythm and dodges, even in the absence of the robber, but following injections, atropine-sensitive theta rhythm and dodging were absent as the animals dropped the food and ran. The results provide the first evidence to link atropine-sensitive theta rhythm and hippocampal structures to a role in sensory integration and planning for the initiation of movement. PMID:9404626

  8. The inversion of shear wave slowness's radial variations based on the dipole flexural mode dispersion%基于偶极弯曲波频散的横波慢度径向分布反演

    Institute of Scientific and Technical Information of China (English)

    马明明; 陈浩; 何晓; 王秀明

    2013-01-01

    本文针对地层横波慢度径向分层模型,分析了地层横波慢度的径向非均匀性对弯曲波频散的影响.基于径向非均匀与均匀模型之间弯曲波频散的差异,结合微扰法和Backus-Gilbert (BG)理论建立了反演横波慢度径向分布的方程,求取了地层横波慢度的径向分布.在无噪声和参数误差时,反演结果较好地反映了实际地层横波慢度的径向分布,当井孔流体或井外地层纵波慢度的选取误差在10%内变化时,反演结果基本保持不变;存在信噪比(SNR)为20 dB(信号的功率为噪声的100倍)或10 dB(信号的功率为噪声的10倍)噪声时,反演结果没有发生明显的改变,其相对误差基本控制在10%以内,可见噪声对反演结果的影响不大.以上反演结果说明,本文采用的结合微扰法和BG理论的反演方法来估测地层横波慢度的径向分布时,具有很好的鲁棒性,可以被用于现场了解井壁周围的地层性质.%Abstract The effect of shear wave slowness's radial heterogeneities on dipole flexural mode dispersions is analyzed for shear wave slowness's radially layered model.Perturbation method and Backus-Gilbert(BG) theory are used for the inversion of shear wave slowness radial variations based on the difference of flexural wave dispersions between radially heterogeneous and homogeneous formations.When there is no noise and error of other parameters,the radial variations of the inverted shear wave slowness agree very well with the assumed radial profile.When the choice of slowness for the borehole fluid or formation compressional wave has a deviation from the true value within 10 percent,the inverted radial variations of shear wave slowness almost remains unchanged.When there exists noise with SNR (Signal Noise Ratio) of 20 dB or 10 dB,the relative error of the inversion results is within 10 percent,which means the impact of noise on the inversion results is little.From the inversion results described

  9. 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) Symptoms The most common symptoms are: Abdominal ...

  10. Prevalence of Bowel Incontinence

    Science.gov (United States)

    ... Incontinence and Aging Managing Incontinence Managing Incontinence: A Survey The Patient's Perspective Barriers on ... is the word used to describe loss of control over when and where we go to the bathroom. It is also called accidental bowel leakage, or ...

  11. Irritable Bowel Syndrome

    Science.gov (United States)

    ... foods are linked to other digestive conditions like lactose intolerance or celiac disease , though, so it's important to ... MORE ON THIS TOPIC Gastroesophageal Reflux Disease (GERD) Lactose Intolerance Inflammatory Bowel Disease Ulcers Digestive System Eating Well ...

  12. Small bowel resection - discharge

    Science.gov (United States)

    ... incision is red, warm, swollen, or more painful Short of breath or chest pain Swollen legs or pain in your calves Alternative Names Small intestine surgery - discharge; Bowel resection - small intestine - discharge; Resection of ...

  13. Irritable bowel syndrome.

    OpenAIRE

    Beck, E.; Hurwitz, B

    1992-01-01

    1. Irritable bowel syndrome is a functional disorder of the lower intestinal tract affecting approximately 10% of the population and causing a wide range of symptoms. 2. Most cases of irritable bowel syndrome can be diagnosed in general practice on the basis of the presenting history and clinical examination but some patients may need to be referred to a gastro-enterologist for further assessment including sigmoidoscopy and barium enema. 3. The clinical picture may include symptoms of abdomin...

  14. 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.

  15. PREVALENCE AND FACTORS AFFECTING REM AND SLOW WAVE SLEEP REBOUND ON CPAP TITRATION STUDY IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA Prevalencia de los factores que afectan el sueño REM y el brote de ondas lentas en los estudios con CPAP en apnea obstructiva del sueño

    OpenAIRE

    Edgar Osuna S; Fouzia Siddiqui; Vanegas, Marco A.; Walters, Arthur S.; Sudhansu Chokroverty

    2008-01-01

    Background. In patients with obstructive sleep apnea syndrome (OSAS) treatment with CPAP results in an increase of REM sleep and slow wave sleep, but there is limited information about the prevalence of REM rebound in patients with OSAS and possible factors related to the rebound. Objective. REM rebound (RR) and slow wave sleep rebound (SWSR) has been described as a frequent phenomenon that occurs during CPAP titration, but the quantity that qualify for RR has not been mentioned in literature...

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

    OpenAIRE

    Kim, Jin-seop; Yi, Seung-Ju

    2014-01-01

    [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...

  17. Ostomy Surgery of the Bowel

    Science.gov (United States)

    ... sustain life. Diarrhea is the main symptom of short bowel syndrome. Other symptoms may include cramping bloating heartburn weakness and fatigue vomiting excessive gas foul-smelling stool Short bowel syndrome is uncommon and can occur with Crohn’s ...

  18. Understanding Bowel Preparation

    Science.gov (United States)

    ... will receive specific instructions. In general, here is what you can expect: Your doctor will prescribe the type of bowel prep that is best for you. ... out if you have any out-ofpocket costs. What determines the type of prep I get? Your medical condition is the most important factor in ...

  19. 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 in t...... epidemiology of IBD....

  20. Sheet Electron Beam and Novel Slow-Wave Structures in Millimeter-Wave and THz Wave Vacuum Devices%毫米波/太赫兹真空器件中的带状电子注和新型慢波结构

    Institute of Scientific and Technical Information of China (English)

    宫玉彬; 魏彦玉; 段兆云; 王战亮; 徐进; 岳玲娜; 赵国庆; 殷海荣; 路志刚

    2013-01-01

    It' s an important way to provide high output power in millimeter-wave and THz wave band by using sheet electron beam. And it becomes one of the most active research directions to study the formation, transportation, and collection of the sheet electron beam and the novel slow wave structures, for increasing the operating frequency, improving the output power, and broadening the operating bandwidth. This article provides an overview of the research and development trends of the sheet electron beam vacuum devices at home and abroad, and puts forward several recommendations for future development.%采用带状电子束是在毫米波和太赫兹波段产生大功率输出的一种重要方法,为了提高工作频率、提高输出功率、拓展工作频带,对带状电子束的形成、传输和收集以及新型慢波结构进行研究,是真空电子学的热点研究方向之一.本文概述了目前国内外带状电子束真空电子器件的研究动态和发展趋势,并提出了今后发展的若干建议.

  1. 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....

  2. Irritable bowel syndrome, inflammatory bowel disease and the microbiome

    OpenAIRE

    Major, Giles; Robin C. Spiller

    2014-01-01

    Purpose of review The review aims to update the reader on current developments in our understanding of how the gut microbiota impact on inflammatory bowel disease and the irritable bowel syndrome. It will also consider current efforts to modulate the microbiota for therapeutic effect. Recent findings Gene polymorphisms associated with inflammatory bowel disease increasingly suggest that interaction with the microbiota drives pathogenesis. This may be through modulation of the immune response,...

  3. 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.

  4. Physiologic effects of bowel preparation

    DEFF Research Database (Denmark)

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

    2004-01-01

    , plasma and extracellular volume, balance function, and biochemical parameters were measured. RESULTS: Bowel preparation led to a significant decrease in exercise capacity (median, 9 percent) and weight (median, 1.2 kg). Plasma osmolality was significantly increased from 287 to 290 mmol kg(-1), as well as...... 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...... increased phosphate and urea concentrations, whereas calcium and potassium concentrations decreased significantly after bowel preparation. No differences in plasma or extracellular volumes were seen. Orthostatic tolerance and balance function did not change after bowel preparation. CONCLUSIONS: Bowel...

  5. Bowel disease after radiotherapy

    International Nuclear Information System (INIS)

    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. (author)

  6. 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.

  7. Physiologic effects of bowel preparation

    DEFF Research Database (Denmark)

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

    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...... preparation has significant adverse physiologic effects, which may be attributed to dehydration. The majority of these findings is small and may not be of clinical relevance in otherwise healthy patients undergoing bowel preparation and following recommendations for oral fluid intake....

  8. Wave

    OpenAIRE

    Ibsen, Lars Bo

    2008-01-01

    Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many times smaller it remains very high. For example, whilst there is enough potential wave power off the UK to supply the electricity demands several times over, the economically recoverable resource for t...

  9. Wave

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    2008-01-01

    Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many...... times smaller it remains very high. For example, whilst there is enough potential wave power off the UK to supply the electricity demands several times over, the economically recoverable resource for the UK is estimated at 25% of current demand; a lot less, but a very substantial amount nonetheless....

  10. Synchronization Properties of Slow Cortical Oscillations

    Science.gov (United States)

    Takekawa, T.; Aoyagi, T.; Fukai, T.

    During slow-wave sleep, the brain shows slow oscillatory activity with remarkable long-range synchrony. Intracellular recordings show that the slow oscillation consists of two phases: an textit{up} state and a textit{down} state. Deriving the phase-response function of simplified neuronal systems, we examine the synchronization properties on slow oscillations between the textit{up} state and the textit{down} state. As a result, the strange interaction functions are found in some parameter ranges. These functions indicate that the states with the smaller phase lag than a critical value are all stable.

  11. Small bowel imaging of inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Emanuele; Casciani; Chiara; De; Vincentiis; Gianfranco; Gualdi

    2015-01-01

    The study of the small bowel(SB) has always beenchallenging both for clinicians and radiologist. It is a long and tortuous tube that can be affected by various pathologies whose signs and symptoms are usually non specific and can mimic other acute abdominal disorders. For these reasons, imaging plays a central role in the diagnosis of the different pathological conditions that can occur. They are important also in the management and follow up of chronic diseases. We expose and evaluate all the radiological methods that are now available for the study of the SB with particular emphasis on the technological improvement of cross-sectional imaging, such as computed tomography(CT) and magnetic resonance imaging(MRI). These techniques have, infact, highly improved in terms of execution times(fast acquisitions images), patients discomfort and radiation dose, for CT, with consequent reduced biological risks. Moreover, the new post-processing options with multiplanar reconstruction and isotropic images have made significant changes in the evaluation of the exams. Especially MRI scans have been improved by the advent of new sequences, such as diffusion weighted imaging and cine-MRI, parallel imaging and breath-hold sequences and can provide excellent soft-tissue contrast without the use of ionizing radiations.

  12. Diagnosis of Irritable Bowel Syndrome

    Science.gov (United States)

    ... your anus. The doctor will fill your large intestine with barium . You may be asked to change positions several times during the test. ​​​​​ ​February 23, 2015​​​​ Previous: Symptoms and Causes of Irritable Bowel Syndrome Next: Treatment for Irritable Bowel Syndrome Digestive Disease ...

  13. Small bowel transplantation: An overview

    NARCIS (Netherlands)

    R.W.F. de Bruin (Ron); E. Heineman (Erik); R.L. Marquet (Richard)

    1994-01-01

    textabstractSmall bowel transplantation (SBT) would, in theory, be the treatment of choice for patients suffering from the short bowel syndrome. Although SBT has been done with a considerable degree of success in some centers [36,145], it is by no means an established or widely applicable therapy fo

  14. Irritable bowel syndrome.

    Science.gov (United States)

    Enck, Paul; Aziz, Qasim; Barbara, Giovanni; Farmer, Adam D; Fukudo, Shin; Mayer, Emeran A; Niesler, Beate; Quigley, Eamonn M M; Rajilić-Stojanović, Mirjana; Schemann, Michael; Schwille-Kiuntke, Juliane; Simren, Magnus; Zipfel, Stephan; Spiller, Robin C

    2016-01-01

    Irritable bowel syndrome (IBS) is a functional gastrointestinal disease with a high population prevalence. The disorder can be debilitating in some patients, whereas others may have mild or moderate symptoms. The most important single risk factors are female sex, younger age and preceding gastrointestinal infections. Clinical symptoms of IBS include abdominal pain or discomfort, stool irregularities and bloating, as well as other somatic, visceral and psychiatric comorbidities. Currently, the diagnosis of IBS is based on symptoms and the exclusion of other organic diseases, and therapy includes drug treatment of the predominant symptoms, nutrition and psychotherapy. Although the underlying pathogenesis is far from understood, aetiological factors include increased epithelial hyperpermeability, dysbiosis, inflammation, visceral hypersensitivity, epigenetics and genetics, and altered brain-gut interactions. IBS considerably affects quality of life and imposes a profound burden on patients, physicians and the health-care system. The past decade has seen remarkable progress in our understanding of functional bowel disorders such as IBS that will be summarized in this Primer. PMID:27159638

  15. Accuracy of abdominal auscultation for bowel obstruction

    DEFF Research Database (Denmark)

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

    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 processed...

  16. Adenocarcinoma of the small bowel

    International Nuclear Information System (INIS)

    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. 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...... fructose caused marked abdominal distress in patients with demonstrable malabsorption. Ingestion of sucrose in these patients gave less pronounced symptoms of abdominal distress. Malabsorption of a 5-g dose of sorbitol could be detected in 8 of 13 patients. Mixtures of 25 g of fructose and 5 g of sorbitol...... caused significantly increased abdominal distress, and more than additive malabsorption was found in several cases. The present study shows that pronounced gastrointestinal distress may be provoked by malabsorption of small amounts of fructose, sorbitol, and fructose-sorbitol mixtures in patients with...

  18. Irritable Bowel Syndrome in Children

    Science.gov (United States)

    ... KB)​​​​​ Alternate Language URL Irritable Bowel Syndrome in Children Page Content On this page: What is irritable ... GI tract [ Top ] How common is IBS in children? Limited information is available about the number of ...

  19. Inflammatory Bowel Disease (For Teens)

    Science.gov (United States)

    ... Just like other organs in your body, the intestines can develop problems or diseases. IBD (which is not the same thing as irritable bowel syndrome, or IBS), can cause more serious problems than ...

  20. Sleep and Irritable Bowel Syndrome

    Science.gov (United States)

    ... Bruce D. Naliboff, PhD, Clinical Professor of Medical Psychology in the Dept. of Psychiatry and Biobehavioral Sciences, ... Gynecological Aspects of Irritable Bowel Syndrome Symptom Diary Testing in IBS Changes You Should Not Ignore if ...

  1. Short bowel syndrome in adults

    DEFF Research Database (Denmark)

    Matarese, Laura E; Jeppesen, Palle B; O'Keefe, Stephen J D

    2014-01-01

    Short bowel syndrome (SBS) is a heterogeneous disorder with broad variation in disease severity arising from different types of intestinal resection. The spectrum of malabsorption ranges from intestinal insufficiency to intestinal failure. Individualized patient strategies involving modifications...

  2. Sleep and Irritable Bowel Syndrome

    Science.gov (United States)

    ... of IBS Who We Are Contact Us Donate Sleep and Irritable Bowel Syndrome Sleep difficulties are common ... More: Treating Pain in IBS How to improve sleep While there are a variety of medications that ...

  3. Neurostimulation for Neurogenic Bowel Dysfunction

    OpenAIRE

    J. Worsøe; Rasmussen, M.; Christensen, P.; Krogh, K.

    2013-01-01

    Background. Loss of normal bowel function caused by nerve injury, neurological disease or congenital defects of the nervous system is termed neurogenic bowel dysfunction (NBD). It usually includes combinations of fecal incontinence, constipation, abdominal pain and bloating. When standard treatment of NBD fails surgical procedures are often needed. Neurostimulation has also been investigated, but no consensus exists about efficacy or clinical use. Methods. A systematic literature search of NB...

  4. 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...

  5. Small Bowel Review - Part I

    OpenAIRE

    Thomson, ABR; Wild, G.

    1997-01-01

    Significant advances have been made in the study of the small bowel. Part I of this two-part review of the small bowel examines carbohydrates, including brush border membrane hydrolysis and sugar transport; amino acids, dipeptides, proteins and food allergy, with a focus on glutamine, peptides and macromolecules, and nucleosides, nucleotides and polyamines; salt and water absorption, and diarrhea, including antidiarrheal therapy and oral rehydration treatment; lipids (digestion and absorption...

  6. Teaching slowing down theory

    International Nuclear Information System (INIS)

    Some of the difficulties and limitations encountered when teaching neutron slowing down theory to nuclear engineering students, are examined. Specific problems in teaching the kinetics of the slowing down of neutrons, the neutron balance equation, resonance escape probabilities, and the continuous slowing down theory, are considered and it is suggested that, as far as possible, use should be made, by analogy, of the work already done with the students in deriving diffusion theory and its one group equation. (U.K.)

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

    Institute of Scientific and Technical Information of China (English)

    Zuhal Ozisler; Kurtulus Koklu; Sumru Ozel; Sibel Unsal-Delialioglu

    2015-01-01

    In this study, we aimed to determine gastrointestinal problems associated with neurogenic bowel dysfunction in spinal cord injury patients and to assess the efifcacy of bowel program on gas-trointestinal problems and the severity of neurogenic bowel dysfunction. Fifty-ifve 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, dififcult intestinal evacuation, incontinence, abdominal pain, abdominal distension, loss of appetite, hemorrhoids, rectal bleeding and gastrointestinal induced autonomic dysrelfexia) and bowel evacuation methods (digital stimulation, oral med-ication, 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 identiifed 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 signiifcantly decreased and constipation, dififcult intestinal evacuation, abdominal distention, and abdominal pain rates were signiifcantly 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.

  8. 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.

  9. Coronal Waves and Oscillations

    OpenAIRE

    Nakariakov Valery M.; Verwichte Erwin

    2005-01-01

    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 interactio...

  10. Space charge wave accelerators

    International Nuclear Information System (INIS)

    We present an account of experimental observations showing control of the wave phase velocity for a slow wave, measurements of the wave electric field, and indicate how these results might apply to an ion accelerator. An interesting and new possibility is also indicated, namely the use of fast waves for electron accelerators. In this case preliminary estimates indicate that comparable field gradients to those already obtained in the slow wave scheme should be obtainable in fast waves and that these field gradients can be maintained at phase velocities close to the speed of light. (orig./HSI)

  11. Clostridium difficile and inflammatory bowel disease.

    OpenAIRE

    Greenfield, C.; Aguilar Ramirez, J R; Pounder, R E; Williams, T.; Danvers, M; Marper, S R; Noone, P

    1983-01-01

    Stools from 109 patients with inflammatory bowel disease (13.4%) contained Clostridium difficile or its toxin, an incidence similar to the stools of 99 control patients with diarrhoea (11.9%), but significantly higher than the stools of 77 control patients with a normal bowel habit (1.4%). Sixty-six per cent of the diarrhoea controls, but only 11% of the inflammatory bowel disease patients, reported recent antibiotic use: however, 67% of inflammatory bowel disease patients were taking sulphas...

  12. Fecal calprotectin in inflammatory bowel disease

    OpenAIRE

    Walsham NE; Sherwood RA

    2016-01-01

    Natalie E Walsham,1 Roy A Sherwood2 1Department of Clinical Biochemistry, University Hospital Lewisham, Lewisham, 2Department of Clinical Biochemistry, Viapath at King’s College Hospital NHS Foundation Trust, London, UK Abstract: Inflammatory bowel disease (IBD) and irritable bowel syndrome share many symptoms. While irritable bowel syndrome is a functional bowel disorder for which no specific treatment is available, the range of effective therapies for IBD is evolving rapidly. Acc...

  13. Small bowel neoplasia in coeliac disease

    OpenAIRE

    Rampertab, S D; Forde, K A; Green, P. H. R.

    2003-01-01

    There is an increased risk of small bowel adenocarcinoma in patients with coeliac disease compared with the normal population. It has been suggested that adenocarcinoma of the small intestine in coeliac disease arises through an adenoma-carcinoma sequence but there has been only one reported case of a small bowel adenoma in a patient with coeliac disease. We report three additional cases of a small bowel adenoma in the setting of coeliac disease. In addition, four cases of small bowel adenoca...

  14. Exitation of Whistler Waves by a Helical Wave Structure

    DEFF Research Database (Denmark)

    Balmashnov, A. A.; Lynov, Jens-Peter; Michelsen, Poul;

    1981-01-01

    The excitation of whistler waves in a radial inhomogeneous plasma is investigated experimentally, using a slow-wave structure consisting of a helix of variable length surrounding the plasma column. The excited waves were observed to have a wave-vector parallel to the external magnetic field. The...... possibility of exciting the waves in different radial regions is demonstrated....

  15. Cutaneous Manifestations in Inflammatory Bowel Diseases

    Directory of Open Access Journals (Sweden)

    Simona Roxana Georgescu

    2015-10-01

    Full Text Available Inflammatory bowel diseases have a high frequency in Europe. They are chronic disorders that evolve with relapses and remissions. Clinical features include the signs of underlying inflammatory bowel disease and also signs of extraintestinal manifestations. Cutaneous disorders are the most common extraintestinal manifestations associated with inflammatory bowel diseases, which can be dependent on or independent of gastrointestinal disease activity. The main cutaneous disorders are erythema nodosum and pyodermagangrenosum. The pathogenic mechanisms are not fully understood but it seems that related mechanisms are involved in the development of inflammatory bowel diseases and extraintestinal manifestations. Treatment should be aimed at both the cutaneous manifestations and the bowel inflammation

  16. CT enteroclysis in small bowel Crohn's disease

    International Nuclear Information System (INIS)

    The diagnostic evaluation of small bowel Crohn's disease has changed dramatically over the last decade. The introduction of wireless capsule endoscopy, double balloon endoscopy and the introduction of newer therapeutic agents have changed the role of imaging in the small bowel. Additionally, advances in multidetector CT technology have further changed how radiologic investigations are utilized in the diagnosis and management of small bowel Crohn's disease. This article describes how we perform CT enteroclysis in the investigation of small bowel Crohn's disease and discusses the role of CT enteroclysis in the current management of small bowel Crohn's disease.

  17. Transformer Industry Productivity Slows.

    Science.gov (United States)

    Otto, Phyllis Flohr

    1981-01-01

    Annual productivity increases averaged 2.4 percent during 1963-79, slowing since 1972 to 1.5 percent; computer-assisted design and product standardization aided growth in output per employee-hour. (Author)

  18. 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. PMID:21918729

  19. Small bowel neuroendocrine tumors: From pathophysiology to clinical approach.

    Science.gov (United States)

    Xavier, Sofia; Rosa, Bruno; Cotter, José

    2016-02-15

    Neuroendocrine tumors (NETs), defined as epithelial tumors with predominant neuroendocrine differentiation, are among the most frequent types of small bowel neoplasm. They represent a rare, slow-growing neoplasm with some characteristics common to all forms and others attributable to the organ of origin. The diagnosis of this subgroup of neoplasia is not usually straight-forward for several reasons. Being a rare form of neoplasm they are frequently not readily considered in the differential diagnosis. Also, clinical manifestations are nonspecific lending the clinician no clue that points directly to this entity. However, the annual incidence of NETs has risen in the last years to 40 to 50 cases per million probably not due to a real increase in incidence but rather due to better diagnostic tools that have become progressively available. Being a rare malignancy, investigation regarding its pathophysiology and efforts toward better understanding and classification of these tumors has been limited until recently. Clinical societies dedicated to this matter are emerging (NANETS, ENETS and UKINETS) and several guidelines were published in an effort to standardize the nomenclature, grading and staging systems as well as diagnosis and management of NETs. Also, some investigation on the genetic behavior of small bowel NETs has been recently released, shedding some light on the pathophysiology of these tumors, and pointing some new directions on the possible treating options. In this review we focus on the current status of the overall knowledge about small bowel NETs, focusing on recent breakthroughs and its potential application on clinical practice. PMID:26909234

  20. 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...

  1. Dysbiosis in inflammatory bowel disease

    OpenAIRE

    Tamboli, C P; Neut, C; Desreumaux, P; Colombel, J.F.

    2004-01-01

    Abundant data have incriminated intestinal bacteria in the initiation and amplification stages of inflammatory bowel diseases. However, the precise role of intestinal bacteria remains elusive. One theory has suggested a breakdown in the balance between putative species of “protective” versus “harmful” intestinal bacteria—this concept has been termed “dysbiosis”. Arguments in support of this concept are discussed.

  2. Cancer in inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Jianlin Xie; Steven H Itzkowitz

    2008-01-01

    Patients with long-standing inflammatory bowel disease (IBD) have an increased risk of developing colorectal cancer (CRC). Many of the molecular alterations responsible for sporadic colorectal cancer, namely chromosomal instability, microsatellite instability, and hypermethylation, also play a role in colitis-associated colon carcinogenesis. Colon cancer risk in inflammatory bowel disease increases with longer duration of colitis, greater anatomic extent of colitis, the presence of primary sclerosing cholangitis, family history of CRC and degree of inflammation of the bowel. Chemoprevention includes aminosalicylates, ursodeoxycholic acid, and possibly folic acid and statins. To reduce CRC mortality in IBD, colonoscopic surveillance with random biopsies remains the major way to detect early mucosal dysplasia. When dysplasia is confirmed, proctocolectomy is considered for these patients. Patients with small intestinal Crohn's disease are at increased risk of small bowel adenocarcinoma. Ulcerative colitis patients with total proctocolectomy and ileal pouch anal- anastomosis have a rather low risk of dysplasia in the ileal pouch, but the anal transition zone should be monitored periodically. Other extra intestinal cancers, such as hepatobiliary and hematopoietic cancer, have shown variable incidence rates. New endoscopic and molecular screening approaches may further refine our current surveillance guidelines and our understanding of the natural history of dysplasia.

  3. Slow medical education.

    Science.gov (United States)

    Wear, Delese; Zarconi, Joseph; Kumagai, Arno; Cole-Kelly, Kathy

    2015-03-01

    Slow medical education borrows from other "slow" movements by offering a complementary orientation to medical education that emphasizes the value of slow and thoughtful reflection and interaction in medical education and clinical care. Such slow experiences, when systematically structured throughout the curriculum, offer ways for learners to engage in thoughtful reflection, dialogue, appreciation, and human understanding, with the hope that they will incorporate these practices throughout their lives as physicians. This Perspective offers several spaces in the medical curriculum where slowing down is possible: while reading and writing at various times in the curriculum and while providing clinical care, focusing particularly on conducting the physical exam and other dimensions of patient care. Time taken to slow down in these ways offers emerging physicians opportunities to more fully incorporate their experiences into a professional identity that embodies reflection, critical awareness, cultural humility, and empathy. The authors argue that these curricular spaces must be created in a very deliberate manner, even on busy ward services, throughout the education of physicians. PMID:25426738

  4. 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.)

  5. Bowel resection in Nigerian children

    Directory of Open Access Journals (Sweden)

    Abdur-Rahman L

    2009-01-01

    Full Text Available Background : Although bowel resections are commonly done for congenital malformations in children in developed countries, they usually follow neglected and preventable acquired diseases of the intestine in developing countries. Objectives : To determine the indications and outcome of bowel resections in children of a developing country in a university teaching hospital. Materials and Methods: Data of the patients operated (from birth to 15 years was retrospectively collected over eight years (January 1999 to December 2006. The biodata of children included the following: Indications for operation, type of operations, duration of admission, and outcome of treatment including complications. Patients with Hirschsprung′s disease were excluded from the study because bowel resection forms part of their definitive surgical management. Results : There were 70 patients (38 boys and 32 girls. The age ranged between four hours to 15 years (median, five months. There were 16 (22.9% neonates, 26 (37.1% infants, and 28 (40% grown children. The indications were congenital anomalies in the 16 neonates. Also, 23 (88.5% infants had intussusception, 2 (7.7% had midgut vovulusm and 1 (3.8% had congenital small intestine band. Among the grown children, typhoid ileal perforation (TIP was seen in 14 (50.0%, intussusception in 5 (17.9%, and other causes in nine patients. Overall, intussusception was the most common indication for bowel resection, followed by TIP. A total of 24 patients developed 33 complications. Complications included wound infection in 47.8% and anastomotic leak in 42.8%. The duration of admission ranged between 4-35 days (median, 15 days. The overall mortality was 17.1% -; which was highest among neonates (56.3%, followed by the infants (26.9% -. Conclusion : Bowel resections are mainly done for intussusception and complications of TIP at our centre. Late presentation, preexisting malnutrition, and nonavailability of parenteral nutrition

  6. The short-bowel syndrome.

    Science.gov (United States)

    Nightingale, J M

    1995-06-01

    Patients with a short bowel have usually had a bowel resection for Crohn's disease. Two types of short-bowel patient can be distinguished: those with a jejunostomy and those with their jejunum anastomosed to a functioning colon. Both types of patient have problems with macronutrient absorption, although those with a colon experience fewer problems because some energy from unabsorbed carbohydrate is salvaged in the colon. Patients with a jejunostomy have problems with large stomal losses of water, sodium and magnesium, whereas those with a jejuno-colic anastomosis rarely have problems with water and electrolyte absorption. Patients with a jejunostomy 100-200 cm from the duodeno-jejunal flexure ('absorbers') usually absorb more from the diet than they pass through the stoma and therefore require oral electrolyte or nutrient supplements. Those with a residual jejunal length of less than 100 cm usually secrete more from the stoma than they take in orally ('secretors') and therefore require long-term parenteral fluid or nutrient supplements. A high output resulting from a jejunostomy is treated by reducing the oral intake of hypotonic fluid, administering a sipped glucose-saline solution and, often, by giving drugs that reduce intestinal motility (most effective in absorbers) or gastrointestinal secretions (most effective in secretors). Gallstones are common both in short-bowel patients with and in those without a colon (45%), and calcium oxalate renal stones occur in the former (25%). However, it is now possible to provide adequate nutrition and fluid supplements for most patients with a short bowel, and the prospects for the rehabilitation of such patients are good. PMID:7552632

  7. Small bowel intubation using guide wire: use in decompression of small bowel obstruction

    International Nuclear Information System (INIS)

    Small bowel intubation is a useful method in the non-operative decompression of small bowel obstruction and enteral hyperalimentation in malnourished patients. We have tried small bowel intubation with Ventrol tube guided by small bowel enteroclysis guide wire (Bilbao-Dotter wire) in 12 patients. Ten cases were successfully intubated. In 11 cases of bowel obstruction, 9 cases were intubated and 8 cases were effectively drained. One malnourished patient was improved in nutritional state after enteral hyperalimentation through the intubated tube. We believe this method is an easy and time-saving method in the small bowel decompression

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

    International Nuclear Information System (INIS)

    Antigranulocyte immunoscintigraphy with 99Tc-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 99Tc-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)

  9. Slow versus fast

    OpenAIRE

    Siniscalchi, Valeria

    2013-01-01

    En s’appuyant sur le travail ethnographique mené par l’auteur depuis 2006 sur le fonctionnement et les dynamiques politiques et économiques de Slow Food (en France d’abord et dans le quartier général en Italie ensuite), l’analyse porte sur l’articulation entre la dimension politique du mouvement, sa philosophie et ses actions dans le champ de l’écologie. Créé en Italie au milieu des années 1980, Slow Food est devenu en moins de vingt ans un mouvement international qui regroupe près de cent mi...

  10. 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.

  11. Heritability in inflammatory bowel disease

    DEFF Research Database (Denmark)

    Gordon, Hannah; Trier Moller, Frederik; Andersen, Vibeke;

    2015-01-01

    Since Tysk et al's pioneering analysis of the Swedish twin registry, twin and family studies continue to support a strong genetic basis of the inflammatory bowel diseases. The coefficient of heritability for siblings of inflammatory bowel disease probands is 25 to 42 for Crohn's disease and 4 to 15...... for ulcerative colitis. Heritability estimates for Crohn's disease and ulcerative colitis from pooled twin studies are 0.75 and 0.67, respectively. However, this is at odds with the much lower heritability estimates from Genome-Wide Association Studies (GWAS). This "missing heritability" is likely due...... estimation regard genetic and environmental variance as separate entities, although it is now understood that there is a complex multidirectional interplay between genetic are environmental factors mediated by the microbiota, the epigenome, and the innate and acquired immune systems. Due to the limitations...

  12. Diet and Inflammatory Bowel Disease

    OpenAIRE

    Knight-Sepulveda, Karina; Kais, Susan; Santaolalla, Rebeca; Abreu, Maria T.

    2015-01-01

    Patients with inflammatory bowel disease (IBD) are increasingly becoming interested in nonpharmacologic approaches to managing their disease. One of the most frequently asked questions of IBD patients is what they should eat. The role of diet has become very important in the prevention and treatment of IBD. Although there is a general lack of rigorous scientific evidence that demonstrates which diet is best for certain patients, several diets—such as the low-fermentable oligosaccharide, disac...

  13. Comorbidity in inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Antonio López San Román; Fernando Mu(n)oz

    2011-01-01

    Patients with inflammatory bowel disease (IBD) can be affected by other unrelated diseases. These are called comorbid conditions, and can include any secondary health problem that affects a person suffering from a primary or main disease, and which is neither linked physiopathologically to the primary condition, nor is it due to the treatments used for the primary condition or to its long-term anatomical or physiological consequences.Different comorbid conditions, as well as their influence on IBD, are discussed.

  14. Inflammatory Bowel Disease and Thrombosis

    OpenAIRE

    Ahmet Tezel; Muzaffer Demir

    2012-01-01

    Inflammatory Bowel Disease (IBD) is a group of chronic and relapsing inflammatory disorders of the gastrointestinal system. In these cases, findings are detected in extraintestinal systems also. There is a tendency for thrombotic events in IBD, as in the other inflammatory processes. The pathogenesis of this thrombotic tendency is multidimensional, including lack of natural anticoagulants, prothrombotic media induced via the inflammatory process, long-term sedentary life style, steroid use, s...

  15. Somatostatin in inflammatory bowel disease

    OpenAIRE

    van Bergeijk, J D; Wilson, J H P

    1997-01-01

    Intestinal inflammation is controlled by various immunomodulating cells, interacting by molecular mediators. Neuropeptides, released by enteric nerve cells and neuroendocrine mucosa cells, are able to affect several aspects of the general and intestinal immune system, with both pro- as well as anti-inflammatory activities. In inflammatory bowel disease (IBD) there is both morphological as well as experimental evidence for involvement of neuropeptides in the pathogenesis. Somatostatin is the m...

  16. Neurostimulation for Neurogenic Bowel Dysfunction

    Directory of Open Access Journals (Sweden)

    J. Worsøe

    2013-01-01

    Full Text Available Background. Loss of normal bowel function caused by nerve injury, neurological disease or congenital defects of the nervous system is termed neurogenic bowel dysfunction (NBD. It usually includes combinations of fecal incontinence, constipation, abdominal pain and bloating. When standard treatment of NBD fails surgical procedures are often needed. Neurostimulation has also been investigated, but no consensus exists about efficacy or clinical use. Methods. A systematic literature search of NBD treated by sacral anterior root stimulation (SARS, sacral nerve stimulation (SNS, peripheral nerve stimulation, magnetic stimulation, and nerve re-routing was made in Pubmed, Embase, Scopus, and the Cochrane Library. Results. SARS improves bowel function in some patients with complete spinal cord injury (SCI. Nerve re-routing is claimed to facilitate defecation through mechanical stimulation of dermatomes in patients with complete or incomplete SCI or myelomeningocele. SNS can reduce NBD in selected patients with a variety of incomplete neurological lesions. Peripheral stimulation using electrical stimulation or magnetic stimulation may represent non-invasive alternatives. Conclusion. Numerous methods of neurostimulation to treat NBD have been investigated in pilot studies or retrospective studies. Therefore, larger controlled trials with well-defined inclusion criteria and endpoints are recommended before widespread clinical use of neurostimulation against NBD.

  17. Management of irritable bowel syndrome.

    Science.gov (United States)

    Torii, Akira; Toda, Gotaro

    2004-05-01

    Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders. The prevalence rate is 10-20% and women have a higher prevalence. IBS adversely affects quality of life and is associated with health care use and costs. IBS comprises a group of functional bowel disorders in which abdominal discomfort or pain is associated with defecation or a change in bowel habit, and with features of disordered defecation. The consensus definition and criteria for IBS have been formalized in the "Rome II criteria". Food, psychiatric disorders, and gastroenteritis are risk factors for developing IBS. The mechanism in IBS involves biopsychosocial disorders; psychosocial factors, altered motility, and heightened sensory function. Brain-gut interaction is the most important in understanding the pathophysiology of IBS. Effective management requires an effective physician-patient relationship. Dietary treatment, lifestyle therapy, behavioral therapy, and pharmacologic therapy play a major role in treating IBS. Calcium polycarbophil can benefit IBS patients with constipation or alternating diarrhea and constipation. PMID:15206545

  18. Primary Amyloidosis Presenting as Small Bowel Encapsulation

    OpenAIRE

    Jones, Jennifer; van Rosendaal, Guido; Cleary, Cynthia; Urbanski, Stefan; Woodman, Richard C.

    2004-01-01

    Amyloidosis is a pathological process which encompasses a spectrum of diseases that result from extracellular deposition of pathological fibrillar proteins. Clinical presentations vary depending on the organs involved. There is no documented case of amyloidosis presenting as small bowel encapsulation. A previously healthy 62-year-old man developed a small bowel obstruction in 1997. At surgery, a peculiar membrane encasing his entire small bowel was discovered. This appeared to have no vascula...

  19. Cutaneous Manifestations in Inflammatory Bowel Diseases

    OpenAIRE

    Simona Roxana Georgescu; Cristina Iulia Mitran; Madalina Irina Mitran; Monica Costescu; Vasile Benea; Maria Isabela Sarbu; Mircea Tampa

    2015-01-01

    Inflammatory bowel diseases have a high frequency in Europe. They are chronic disorders that evolve with relapses and remissions. Clinical features include the signs of underlying inflammatory bowel disease and also signs of extraintestinal manifestations. Cutaneous disorders are the most common extraintestinal manifestations associated with inflammatory bowel diseases, which can be dependent on or independent of gastrointestinal disease activity. The main cutaneous disorders are erythema nod...

  20. Anorexia nervosa complicating inflammatory bowel disease.

    OpenAIRE

    Mallett, P; MURCH, S.

    1990-01-01

    Two cases of inflammatory bowel disease, occurring in adolescence and complicated by anorexia nervosa, are presented. The management of the bowel disease with corticosteroids appeared to precipitate the eating disorder in one case whereas covert withdrawal of steroid treatment led to life threatening complications of inflammatory bowel disease in the other. The difficulties of managing two serious conditions, each ideally treated in a specialist centre, are discussed and the dangers of treati...

  1. Slow transit constipation: A functional disorder becomes an enteric neuropathy

    Institute of Scientific and Technical Information of China (English)

    Gabrio Bassotti; Vincenzo Villanacci

    2006-01-01

    Slow transit constipation has been traditionally considered and classified as a functional disorder.However, clinical and manometric evidence has been accumulating that suggests how most of the motility alterations in STC might be considered of neuropathic type. In addition, further investigations showed that subtle alterations of the enteric nervous system, not evident to conventional histological examination, may be present in these patients. In the present article we will discuss these evidences, and will try to put them in relation with the abnormal motor function of the large bowel documented in this pathological condition.

  2. Segmental reversal of the small bowel as treatment of short bowel syndrome in adults

    DEFF Research Database (Denmark)

    Burgdorf, Stefan K; Qvist, Niels; Gögenur, Ismail

    2014-01-01

    Short bowel syndrome is the result of extensive surgical resection, inherited defects or loss of functional absorbing intestine. Parenteral nutrition is associated with high economical expenses, increased morbidity and decreased quality of life. Intestinal transplantation is associated with high...... morbidity and mortality rates. Segmental reversal of the small bowel can prolong the transit time in the small bowel and in many cases permanently end parenteral nutrition dependency. Segmental reversal of the small bowel should be integrated in the surgical treatment of adults with short bowel syndrome....

  3. Slow kaon beams

    International Nuclear Information System (INIS)

    A short description is given of considerations for the design of low-momentum kaon beam lines. Relevant data for the performance of seven existing and decommissioned slow kaon beams are presented. For single-stage separated beams the observed ratio all/K- is greater than 50 for momenta less than 500 MeV/c. We recommend a two-stage separated beam with perhaps an upstream cleanup section for maximal purity

  4. Bowel perforation detection using metabolic fluorescent chlorophylls

    Science.gov (United States)

    Han, Jung Hyun; Jo, Young Goun; Kim, Jung Chul; Choi, Sujeong; Kang, Hoonsoo; Kim, Yong-Chul; Hwang, In-Wook

    2016-03-01

    Thus far, there have been tries of detection of disease using fluorescent materials. We introduce the chlorophyll derivatives from food plants, which have longer-wavelength emissions (at >650 nm) than those of fluorescence of tissues and organs, for detection of bowel perforation. To figure out the possibility of fluorescence spectroscopy as a monitoring sensor of bowel perforation, fluorescence from organs of rodent models, intestinal and peritoneal fluids of rodent models and human were analyzed. In IVIS fluorescence image of rodent abdominal organ, visualization of perforated area only was possible when threshold of image is extremely finely controlled. Generally, both perforated area of bowel and normal bowel which filled with large amount of chlorophyll derivatives were visualized with fluorescence. The fluorescence from chlorophyll derivatives penetrated through the normal bowel wall makes difficult to distinguish perforation area from normal bowel with direct visualization of fluorescence. However, intestinal fluids containing chlorophyll derivatives from food contents can leak from perforation sites in situation of bowel perforation. It may show brighter and longer-wavelength regime emissions of chlorophyll derivatives than those of pure peritoneal fluid or bioorgans. Peritoneal fluid mixed with intestinal fluids show much brighter emissions in longer wavelength (at>650 nm) than those of pure peritoneal fluid. In addition, irrigation fluid, which is used for the cleansing of organ and peritoneal cavity, made of mixed intestinal and peritoneal fluid diluted with physiologic saline also can be monitored bowel perforation during surgery.

  5. Pregnancy outcome in inflammatory bowel disease

    DEFF Research Database (Denmark)

    Bortoli, A; Pedersen, N; Duricova, D; D'Inca, R; Gionchetti, P; Panelli, M R; Ardizzone, S; Sanroman, A L; Gisbert, J P; Arena, I; Riegler, G; Marrollo, M; Valpiani, D; Corbellini, A; Segato, S; Castiglione, F; Munkholm, P

    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....

  6. 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...

  7. 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 r...

  8. Hypertrophic osteoarthropathy of chronic inflammatory bowel disease

    Energy Technology Data Exchange (ETDEWEB)

    Oppenheimer, D.A.; Jones, H.H.

    1982-12-01

    The case of a 14-year old girl with painful periostitis and ulcerative colitis is reported. The association of chronic inflammatory bowel disease with osteoarthropathy is rare and has previously been reported in eight patients. The periosteal reaction found in association with inflammatory bowel disease is apparently related to a chronic disease course and may cause extreme localized pain.

  9. Hypertrophic osteoarthropathy of chronic inflammatory bowel disease

    International Nuclear Information System (INIS)

    The case of a 14-year old girl with painful periostitis and ulcerative colitis is reported. The association of chronic inflammatory bowel disease with osteoarthropathy is rare and has previously been reported in eight patients. The periosteal reaction found in association with inflammatory bowel disease is apparently related to a chronic disease course and may cause extreme localized pain. (orig.)

  10. Surgical techniques in short bowel syndrome.

    Science.gov (United States)

    Waag, K L; Heller, K

    1990-01-01

    An operation according to Bianchi in a 2-year-old girl is described and indications as well as technical procedure are discussed. The girl was born with a gastroschisis. There was a jejunal perforation 10 cm below the ligament of Treitz caused by a volvulus. Only 20 cm of the jejunum remained. Moreover, only the left part of the colon was present. Total parenteral nutrition for 2 years was necessary. The principle of the operation is based on a longitudinal division of the remaining bowel and a creation of two separate bowel tubes out of the divided bowel halves, thus effecting an isoperistaltic serial connection by means of two anastomoses. This is technically possible since each half of the bowel wall has its own blood supply. The vessels originating from the mesenterium branch off before they reach the bowel wall so that the mesenteric dissection line can be anastomosed longitudinally with the antimesenteric border. This results in doubling of the bowel length, narrowing of the preoperatively dilated bowel diameter, closer contact of bowel contents with the mucosa, prolonged transit time and a Bacteroides colonization which is reduced by more effective peristalsis. Indications, time of operation and our own experiences are discussed and three cases are described. All children are alive and show marked improvement in nutrition. PMID:2105523

  11. Radiological Evaluation of Bowel Ischemia.

    Science.gov (United States)

    Dhatt, Harpreet S; Behr, Spencer C; Miracle, Aaron; Wang, Zhen Jane; Yeh, Benjamin M

    2015-11-01

    Intestinal ischemia, which refers to insufficient blood flow to the bowel, is a potentially catastrophic entity that may require emergent intervention or surgery in the acute setting. Although the clinical signs and symptoms of intestinal ischemia are nonspecific, computed tomography (CT) findings can be highly suggestive in the correct clinical setting. In our article, we review the CT diagnosis of arterial, venous, and nonocclusive intestinal ischemia. We discuss the vascular anatomy, pathophysiology of intestinal ischemia, CT techniques for optimal imaging, key and ancillary radiological findings, and differential diagnosis. PMID:26526436

  12. [Inflammatory bowel disease and pregnancy].

    Science.gov (United States)

    Parfenov, A I

    2012-01-01

    Inflammatory bowel disease (IBD) in pregnant women in their characteristics do not differ from general population, unless they had operations on the pelvic organs. Women with a first pregnancy, regardless of the activity of IBD have an increased risk of adverse pregnancy and high risk births. Most treatment methods are compatible with pregnancy and breastfeeding. Women affected by IBD should discuss their plans for pregnancy with the doctor first in order to know the possible dangers. Every patient in the IBD during pregnancy must be observed by a gastroenterologist, accoucheur and pediatrician to ensure peace of mother and child. PMID:22830229

  13. Immunopathogenesis of inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    David Q Shih; Stephan R Targan

    2008-01-01

    Crohn's disease and ulcerative colitis are chronic relapsing immune mediated disorders that results from an aberrant response to gut luminal antigen in genetically susceptible host. The adaptive immune response that is then triggered was widely considered to be a T-helper-1 mediated condition in Crohn's disease and T-helper-2 mediated condition in ulcerative colitis. Recent studies in animal models, genome wide association, and basic science has provided important insights in in the immunopathogenesis of inflammatory bowel disease, one of which was the characterization of the interleukin-23/Th-17 axis.

  14. PPARγ in Inflammatory Bowel Disease

    Directory of Open Access Journals (Sweden)

    Vito Annese

    2012-01-01

    Full Text Available Peroxisome proliferator-activated receptor gamma (PPARγ is member of a family of nuclear receptors that interacts with nuclear proteins acting as coactivators and corepressors. The colon is a major tissue which expresses PPARγ in epithelial cells and, to a lesser degree, in macrophages and lymphocytes and plays a role in the regulation of intestinal inflammation. Indeed, both natural and synthetic PPARγ ligands have beneficial effects in different models of experimental colitis, with possible implication in the therapy of inflammatory bowel disease (IBD. This paper will specifically focus on potential role of PPARγ in the predisposition and physiopathology of IBD and will analyze its possible role in medical therapy.

  15. Continuous spike-waves during slow waves sleep: a clinical and electroencephalografic study in fifteen children Ponta-onda contínua do sono lento: estudo clínico e eletrencefalográfico em quinze crianças

    Directory of Open Access Journals (Sweden)

    ADRIANA A. F. DJABRAIAN

    1999-09-01

    Full Text Available We report on the clinical and EEG features of 15 patients with the syndrome of "continuous spike waves during slow wave sleep" (CSWSS. The differential diagnosis of CSWSS includes benign epilepsy of childhood with centro-temporal spikes, and Landau-Kleffner and Lennox-Gastaut syndromes. We found normal CT and MRI features in 6 cases, periventricular leukomalacia with and without diffuse brain atrophy in 4 cases and hydrocephalus in 1 case. There was no association between specific neurological findings and CSWSS. Nine of our cases had relatively focal discharges, like some cases from the literature. The occurrence of CSWSS appears to be age-related, generaly between the ages of 5 to 12 years, with a strong temporal relation to the neupsychological deterioration in its nature, severity and prognosis. We believe that this striking disorder has been overlooked and that routine sleep EEG studies on epileptic children may disclose additional cases of CSWSS.Relatamos as características clínicas e eletroencefalográficas de 15 patientes com a síndrome de ponta-onda contínua do sono não-REM (POCSNR. O diagnóstico diferencial da POCSNR inclue a epilepsia benigna da infância com pontas centro-temporais e as síndromes de Landau-Kleffner e Lennox-Gastaut. Encontramos TC e RNM de crânio normais em 6 casos, leucomalácia periventricular em 4 e hidrocefalia em 1. Não houve associação de achados neurológicos específicos e a POCSNR. Nove dos nossos casos tinham descargas relativamente focais, como alguns casos da literatura. A ocorrência da POCSNR parece ser idade-dependente, geralmente entre 5 e 12 anos, com forte relação temporal à deteriorização neurocognitiva, em sua natureza, severidade e prognóstico. Acreditamos que esta síndrome tem sido pouco diagnosticada e que a realização rotineira de EEG em sono em crianças epilépticas possa revelar novos casos de POCSNR.

  16. Abnormal amplification of sound waves refracted by an oblique shock wave

    OpenAIRE

    Nakamura, Yoshiaki; Menshov, Igor; 中村 佳朗

    2004-01-01

    Reflection and refraction of linear disturbance waves by an oblique shock wave is studied by a linear analysis. Several different cases are considered, when the incident plane wave is a fast acoustic, slow acoustic, entropy, or vorticity wave. Results show that 1) a critical angle of the wave incidence exists, beyond which the regular wave solution of the linear problem can not be realized, 2) strongest sound waves are generated behind the shock wave, if the incident wave strikes the shock wa...

  17. Go, Slow, and Whoa Foods

    Science.gov (United States)

    ... quick tips for seasonal health, safety and fun Go, Slow, and Whoa Foods Past Issues / Summer 2007 ... of California and Flaghouse, Inc. 2002 Food Group GO Almost anytime foods SLOW Sometimes foods WHOA Once ...

  18. Slowed Exports Growth

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The first half of 2010 is showing that the impacts of the financial crisis are still lingering.Zhao Jinping,a researcher at the Development Research Center of the State Council,says that the possible implementation of exit strategies in developed countries may deal a heavy blow to a global rally,and it will certainly result in slowed exports growth for China.Zhao published his opinion in the China Economic Times.The first part was published in issue No.33.Edited excerpts of the second part follow:

  19. Quantum gravity slows inflation

    Energy Technology Data Exchange (ETDEWEB)

    Tsamis, N.C. [Ecole Polytechnique, 91 - Palaiseau (France). Centre de Physique]|[Theory Group, FORTH, Heraklion, Crete (Greece); Woodard, R.P. [Florida Univ., Gainesville, FL (United States). Dept. of Physics

    1996-02-01

    We consider the quantum gravitational back-reaction on an initially inflating, homogeneous and isotropic universe whose topology is T{sup 3} {times} {Re}. Although there is no secular effect at one loop, an explicit calculation shows that two-loop processes act to slow the rate of expansion by an amount which becomes non-pertubatively large at late times. By exploiting Feynman`s tree theorem we show that all higher loops act in the same sense. 18 refs., 1 fig.

  20. [Inflammatory Bowel Disease Competence Network].

    Science.gov (United States)

    Schreiber, Stefan; Hartmann, Heinz; Kruis, Wolfgang; Kucharzik, Torsten; Mudter, Jonas; Siegmund, Britta; Stallmach, Andreas; Witte, Christine; Fitzke, Klaus; Bokemeyer, Bernd

    2016-04-01

    The Inflammatory Bowel Disease Competence Network is a network of more than 500 physicians and scientists from university clinics, hospitals and gastroenterology practices. The focus extends from the two major forms of inflammatory bowel diseases, Crohn's disease and ulcerative colitis, into other chronic inflammatory conditions affecting the intestine, including coeliac disease and microscopic colitis. The network translates basic science discoveries (in particular in the molecular epidemiology research) into innovative diagnostics and therapy. Through its strong networking structures it supports a continuous process to improve quality and standardisation in patient care that is implemented in close interaction with European networks addressing this disease group.Optimisation of patient care based on scientifically proven evidence is a main focus of the network. Therefore, it supports and coordinates translational research and infrastructure projects that investigate aetiology, improvement of diagnostic methods, and development of new or improved use of established therapies. Members participate in various training projects, thus ensuring the rapid transfer of research results into clinical practice.The competence network cooperates with the main patient organisations to engage patients in all levels of activities. The network and the patient organisations have interest in promoting public awareness about the disease entities, because their importance and burden is underestimated in non-specialised medical fields and among the general public. PMID:26968556

  1. 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.

  2. Slow Light Devices and Their Applications to Microwaves and Photonics

    OpenAIRE

    Santagiustina, M.; Eisenstein, G.; Thévenaz, Luc; Capmany, J.; Mork, J.; Reithmaier, J. P.; Rossi, A.; Sales, S; Yvind, K.; Combrié, S.; Bourderionnet, J

    2012-01-01

    Recently developed, highly effective technologies enabling slow light propagation as a tunable feature in photonic devices, are reviewed. Several applications in ICT are also demonstrated. Controlling the group velocity of light offers a broadband solution to a necessary functionality in microwave and millimeter wave systems: a tunable time-delay/phase-shift line. Moreover, slow light can highly enhance the nonlinearity, thus opening the way to on chip, nonlinear photonics.

  3. Forward Modelling of Standing Slow Modes in Flaring Coronal Loops

    CERN Document Server

    Yuan, D; Banerjee, D; Antolin, P

    2015-01-01

    Standing slow mode waves in hot flaring loops are exclusively observed in spectrometers and are used to diagnose the magnetic field strength and temperature of the loop structure. Due to the lack of spatial information, the longitudinal mode cannot be effectively identified. In this study, we simulate standing slow mode waves in flaring loops and compare the synthesized line emission properties with SUMER spectrographic and SDO/AIA imaging observations. We find that the emission intensity and line width oscillations are a quarter period out of phase with Doppler shift velocity both in time and spatial domain, which can be used to identify a standing slow mode wave from spectroscopic observations. However, the longitudinal overtones could be only measured with the assistance of imagers. We find emission intensity asymmetry in the positive and negative modulations, this is because the contribution function pertaining to the atomic emission process responds differently to positive and negative temperature variat...

  4. Current Role of Ultrasound in Small Bowel Imaging.

    Science.gov (United States)

    Wale, Anita; Pilcher, James

    2016-08-01

    Bowel ultrasound is cheap, relatively quick, allows dynamic evaluation of the bowel, has no radiation burden, is well tolerated by patients, and allows repeat imaging. Bowel ultrasound requires a systematic assessment of the entire bowel using high-frequency probes. In addition, hydrosonography and contrast-enhanced ultrasound may be performed. We present the normal sonographic appearances of large and small bowel and the sonographic appearances of acute appendicitis, Crohn's disease, celiac disease, intussusception, infectious enteritis, intestinal tuberculosis, small bowel ileus and obstruction, small bowel ischemia, and malignant tumors. PMID:27342894

  5. 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...

  6. Slow microwaves in left-handed materials

    Science.gov (United States)

    di Gennaro, E.; Parimi, P. V.; Lu, W. T.; Sridhar, S.; Derov, J. S.; Turchinetz, B.

    2005-07-01

    Remarkably slow propagation of microwaves in two different classes of left-handed materials (LHM’s) is reported from microwave-pulse and continuous-wave transmission measurements. Microwave dispersion in a composite LHM made of split-ring resonators and wire strips reveals group velocity vg˜c/50 , where c is the free-space light velocity. Photonic crystals (PhC’s) made of dielectric Al2O3 rods reveal vg˜c/10 . Group delay dispersion of both the composite LHM and PhC’s determined from the experiment is in complete agreement with that obtained from theory. The slow group velocities are quantitatively described by the strong dispersion observed in these materials.

  7. Investigation of a bi-periodical slowing down structure

    International Nuclear Information System (INIS)

    General properties of bi-periodical slowing down structures on the base of a resonator chain consisting from accelerating resonators (one quarter of the wave length) and connective resonators (one half wave split) and operating on the standing wave in the matching regime at π-wave were investigated. It was shown that the developed structure can be effectively used for acceleration of heavy charged particles up to the energies 100...150 MeV/nucl. (author). 14 refs., 1 tab., 13 figs

  8. Slowed Exports Growth

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ Ⅲ. Slowed export recovery in the second half Since the beginning of this year, global trade has maintained a recovery growth thanks to the worldwide economic rally.From January to April, the imports of three major Economics--the United States, the euro zone and Japan--rose 17.5 percent on average from a year ago. Import growths for the United States, the euro zone and Japan were 20.9 percent, 4.8 percent and 29 percent, respectively, which spurred China's exports to those regions. From January to June this year, China's exports totaled $705.09 billion, up 35.2 percent from the same period in 2009 and were 5.8 percent higher than the first half of 2008 when the crisis had yet to begin. Those figures indicated China's exports had rebounded to precrisis levels.

  9. Short bowel syndrom as a complication of Crohn's disease

    OpenAIRE

    Skok, Pavel; Ocepek, Andreja

    2015-01-01

    During the course of Crohn's disease, some patients require surgical bowel resection due to intestinal stenosis. Attention is drawn to a possible complication of such surgical procedures: in a patients with Crohn's disease, short bowel syndrome developed following several small and large intestine resections that were necessary in the treatment of recidiving acute bowel obstructions. When the remnant small bowel is shorter than 200 cm, characteristic symptoms of short bowel syndrome develop i...

  10. No difference in small bowel microbiota between patients with irritable bowel syndrome and healthy controls

    OpenAIRE

    Aldona Dlugosz; Björn Winckler; Elin Lundin; Katherina Zakikhany; Gunnar Sandström; Weimin Ye; Lars Engstrand; Greger Lindberg

    2015-01-01

    Several studies have indicated that colonic microbiota may exhibit important differences between patients with irritable bowel syndrome (IBS) and healthy controls. Less is known about the microbiota of the small bowel. We used massive parallel sequencing to explore the composition of small bowel mucosa-associated microbiota in patients with IBS and healthy controls. We analysed capsule biopsies from the jejunum of 35 patients (26 females) with IBS aged 18-(36)-57 years and 16 healthy voluntee...

  11. Diet and Inflammatory Bowel Disease.

    Science.gov (United States)

    Knight-Sepulveda, Karina; Kais, Susan; Santaolalla, Rebeca; Abreu, Maria T

    2015-08-01

    Patients with inflammatory bowel disease (IBD) are increasingly becoming interested in nonpharmacologic approaches to managing their disease. One of the most frequently asked questions of IBD patients is what they should eat. The role of diet has become very important in the prevention and treatment of IBD. Although there is a general lack of rigorous scientific evidence that demonstrates which diet is best for certain patients, several diets-such as the low-fermentable oligosaccharide, disaccharide, monosaccharide, and polyol diet; the specific carbohydrate diet; the anti-inflammatory diet; and the Paleolithic diet-have become popular. This article discusses the diets commonly recommended to IBD patients and reviews the supporting data. PMID:27118948

  12. Semitransparent peroral small bowel imaging

    Energy Technology Data Exchange (ETDEWEB)

    Emons, D.

    1981-10-01

    171 follow-through examinations of the small bowel performed in children and adolescents with a large contrast medium meal and the high voltage-low density barium technique (10 to 25 g BaSO/sub 4//100 ml, depending on age), are described. A ready made suspension, diluted with water, proved unsatisfactory. Coating properties and stability of the diluted, weak suspension were then greatly improved by hydroxyethylcellulose as a thickening agent and in addition by premedication of the patient with cimetidine. Pure cellulose solution instead of the last portion of barium prevented thickening in the ileum. The procedure has the well known advantages of a large contrast medium meal without the problem of overly dense superpositions.

  13. Disturbances in small bowel motility.

    LENUS (Irish Health Repository)

    Quigley, E M

    2012-02-03

    Recently, the small intestine has become the focus of investigation as a potential site of dysmotility in the irritable bowel syndrome (IBS). A number of motor abnormalities have been defined in some studies, and include \\'clustered\\' contractions, exaggerated post-prandial motor response and disturbances in intestinal transit. The significance of these findings remains unclear. The interpretation of available studies is complicated by differences in subject selection, the direct influence of certain symptoms, such as diarrhoea and constipation, and the interference of compounding factors, such as stress and psychopathology. Dysmotility could also reflect autonomic dysfunction, disturbed CNS control and the response to heightened visceral sensation or central perception. While motor abnormalities may not explain all symptoms in IBS, sensorimotor interactions may be important in symptom pathogenesis and deserve further study.

  14. Genetics of irritable bowel syndrome.

    Science.gov (United States)

    Henström, Maria; D'Amato, Mauro

    2016-12-01

    Irritable bowel syndrome (IBS) is a common condition with a complex and largely unknown etiology. There is no cure, and treatment options are mainly directed to the amelioration of symptoms. IBS causes reduced quality of life and poses considerable repercussions on health and socioeconomic systems. There is a heritable component in IBS, and genetic research is a valuable tool for the identification of causative pathways, which will provide important insight into the pathophysiology. However, although some gene-hunting efforts have been conducted and a few risk genes proposed, IBS genetic research is lagging behind compared to other complex diseases. In this mini-review, we briefly summarize existing genetic studies, discuss the main challenges in IBS genetic research, and propose strategies to overcome these challenges for IBS gene discovery. PMID:26873717

  15. Diet in irritable bowel syndrome.

    Science.gov (United States)

    El-Salhy, Magdy; Gundersen, Doris

    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-coeliac gluten sensitivity (NCGS). The component in wheat that triggers symptoms in NCGS appears to be the carbohydrates. Patients with NCGS appear to be IBS patients who are self-diagnosed and self-treated with a gluten-free diet. IBS symptoms are triggered by the consumption of the poorly absorbed fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) and insoluble fibre. On reaching the distal small intestine and colon, FODMAPS and insoluble fibre increase the osmotic pressure in the large-intestine lumen and provide a substrate for bacterial fermentation, with consequent gas production, abdominal distension and abdominal pain or discomfort. Poor FODMAPS and insoluble fibres diet reduces the symptom and improve the quality of life in IBS patients. Moreover, it changes favourably the intestinal microbiota and restores the abnormalities in the gastrointestinal endocrine cells. Five gastrointestinal endocrine cell types that produce hormones regulating appetite and food intake are abnormal in IBS patients. Based on these hormonal abnormalities, one would expect that IBS patients to have increased food intake and body weight gain. However, the link between obesity and IBS is not fully studied. Individual dietary guidance for intake of poor FODMAPs and insoluble fibres diet in combination with probiotics intake and regular exercise is to be recommended for IBS patients. PMID:25880820

  16. Atom slowing via dispersive optical interactions

    Science.gov (United States)

    Hamamda, M.; Boustimi, M.; Correia, F.; Baudon, J.; Taillandier-Loize, T.; Dutier, G.; Perales, F.; Ducloy, M.

    2012-02-01

    A promising technique of atom slowing is proposed. It is based upon the dispersive interaction of atoms with optical potential pulses generated by a far-off-resonance standing wave modulated in time. Each pulse reduces the velocity by a small amount. By repeating the process thousands of times, the velocity can be lowered from several hundreds of meters per second down to almost zero, over a path as short as 20cm. In the absence of any random recoil process, the initial characteristics of the beam are preserved.

  17. Moving Crystal Slow-Neutron Wavelength Analyser

    DEFF Research Database (Denmark)

    Buras, B.; Kjems, Jørgen

    1973-01-01

    Experimental proof that a moving single crystal can serve as a slow-neutron wavelength analyser of special features is presented. When the crystal moves with a velocity h/(2 md) (h-Planck constant, m-neutron mass, d-interplanar spacing) perpendicular to the diffracting plane and the analysed...... neutron beam is parallel to the diffracting plane, then neutrons of different wave-lengths contained in the incident beam are simultaneously diffracted under different reflection angles and recorded by a position-sensitive detector. Special features of this analysing system are briefly discussed....

  18. Directed Relativistic Blast Wave

    OpenAIRE

    Gruzinov, Andrei

    2007-01-01

    A spherically symmetrical ultra-relativistic blast wave is not an attractor of a generic asymmetric explosion. Spherical symmetry is reached only by the time the blast wave slows down to non-relativistic velocities, when the Sedov-Taylor-von Neumann attractor solution sets in. We show however, that a directed relativistic explosion, with the explosion momentum close to the explosion energy, produces a blast wave with a universal intermediate asymptotic -- a selfsimilar directed ultra-relativi...

  19. Magnetic resonance imaging of the small bowel

    Energy Technology Data Exchange (ETDEWEB)

    Deeab, Dhafer A., E-mail: dhafer_ahmed@yahoo.co [Department of Radiology, St Mary' s Campus, Imperial College NHS Trust, London (United Kingdom); Dick, Elizabeth; Sergot, Antoni A.; Sundblon, Lauren; Gedroyc, Wady [Department of Radiology, St Mary' s Campus, Imperial College NHS Trust, London (United Kingdom)

    2011-02-15

    Magnetic Resonance Imaging of the Small Bowel (MR Enterography, or MRE) is becoming increasingly popular as the first imaging modality for the diagnosis and follow-up of small bowel diseases. The inherent advantages of MRI, including excellent soft tissue contrast, multiplanar capability and lack of ionising radiation are well known. In addition, the use of luminal contrast agents in MRE has the added advantage of demonstrating the lumen and the wall directly, something not possible to achieve with conventional small bowel barium follow-through imaging. This review will highlight recent technical advances to this low cost, simple technique which is easily achievable in all hospitals. It will also review normal and abnormal radiological findings and highlight the value of this technique to both the clinician and patient alike in the investigation of small bowel disease.

  20. Magnetic resonance imaging of the small bowel

    International Nuclear Information System (INIS)

    Magnetic Resonance Imaging of the Small Bowel (MR Enterography, or MRE) is becoming increasingly popular as the first imaging modality for the diagnosis and follow-up of small bowel diseases. The inherent advantages of MRI, including excellent soft tissue contrast, multiplanar capability and lack of ionising radiation are well known. In addition, the use of luminal contrast agents in MRE has the added advantage of demonstrating the lumen and the wall directly, something not possible to achieve with conventional small bowel barium follow-through imaging. This review will highlight recent technical advances to this low cost, simple technique which is easily achievable in all hospitals. It will also review normal and abnormal radiological findings and highlight the value of this technique to both the clinician and patient alike in the investigation of small bowel disease.

  1. Use of thiopurines in inflammatory bowel disease

    DEFF Research Database (Denmark)

    Frei, Pascal; Biedermann, Luc; Nielsen, Ole Haagen;

    2013-01-01

    The use of thiopurines as immunosuppression for the treatment of refractory or chronic active inflammatory bowel disease is established for both Crohn's disease and ulcerative colitis. Nevertheless, many questions remain concerning the optimal treatment regimens of azathioprine, 6-mercaptopurine ...

  2. Fecal calprotectin in inflammatory bowel disease.

    Science.gov (United States)

    Walsham, Natalie E; Sherwood, Roy A

    2016-01-01

    Inflammatory bowel disease (IBD) and irritable bowel syndrome share many symptoms. While irritable bowel syndrome is a functional bowel disorder for which no specific treatment is available, the range of effective therapies for IBD is evolving rapidly. Accurate diagnosis of IBD is therefore essential. Clinical assessment, together with various imaging modalities and endoscopy, has been the mainstay of diagnosis for many years. Fecal biomarkers of gastrointestinal inflammation have appeared in the past decade, of which calprotectin, a neutrophil cytosolic protein, has been studied the most. Crohn's disease and ulcerative colitis are chronic remitting and relapsing diseases, and objective assessment of disease activity and response to treatment are important. This review focuses on the use of fecal calprotectin measurements in the diagnosis and monitoring of patients with IBD. PMID:26869808

  3. Genetic epidemiology of irritable bowel syndrome

    OpenAIRE

    Makker, Jasbir; Chilimuri, Sridhar; Bella, Jonathan N

    2015-01-01

    Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder characterized by presence of abdominal pain or discomfort associated with altered bowel habits. It has three main subtypes - constipation predominant IBS (C-IBS), diarrhea predominant IBS (D-IBS) and IBS with mixed features of both diarrhea as well as constipation (M-IBS). Its pathophysiology and underlying mechanisms remain elusive. It is traditionally believed that IBS is a result of multiple factors incl...

  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. Rifaximin Therapy of Irritable Bowel Syndrome

    OpenAIRE

    Koo, Hoonmo L.; Saman Sabounchi; Huang, David B.; Herbert L. DuPont

    2012-01-01

    Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by abdominal pain and altered bowel habits in the absence of specific organic pathology. Although the underlying pathogenesis of IBS is not well-understood, small intestinal bacterial overgrowth (SIBO) or other abnormalities in the gut flora is believed to contribute to the development of a subset of IBS cases. Rifaximin is a poorly absorbed antimicrobial with activity against enteric pathogens. A number of stu...

  6. Cutaneous manifestations of inflammatory bowel disease

    Directory of Open Access Journals (Sweden)

    Al Roujayee Abdulaziz

    2007-01-01

    Full Text Available Inflammatory bowel disease (IBD has many extraintestinal manifestations, and skin lesions are one of the most frequently described extraintestinal findings. Reports indicate an incidence of cutaneous manifestations ranging from 2 to 34%, Cutaneous manifestations are usually related to the activity of the bowel disease but may have an independent course. In this review we aim to address the various cutaneous manifestations associated with IBD, their impact on the disease course, and the treatment options available.

  7. NATURAL AGENTS FOR INFLAMMATORY BOWEL DISEASE

    OpenAIRE

    Darji Vinay Chhanalal; Bariya Aditi Hemrajbhai; Deshpande Shrikalp Shrikant

    2011-01-01

    Inflammatory bowel disease (IBD) is a chronic inflammatory disease of gastrointestinal tract. It comprises the two conditions, Crohn’s disease and ulcerative colitis, characterized by chronic recurrent ulceration of the bowel. Conventional drugs for colitis treatment include aminosalicylate, corticosteroids,antibiotics & immunomodulators. 5- Amino salicylic acid having side effects in 30% of the patients. Systemic corticosteroids producing incidence of complication is 4.3%. Antibiotic therapy...

  8. Delayed bowel perforation following suprapubic catheter insertion

    OpenAIRE

    Mehta Ajay; Ahmed Shwan J; Rimington Peter

    2004-01-01

    Abstract Background Complications of suprapubic catheter insertion are rare but can be significant. We describe an unusual complication of a delayed bowel perforation following suprapubic catheter insertion. Case presentation A gentleman presented with features of peritonitis and feculent discharge along a suprapubic catheter two months after insertion of the catheter. Conclusion Bowel perforation is the most feared complication of suprapubic catheter insertion especially in patients with low...

  9. Small bowel emergency surgery: literature's review

    Directory of Open Access Journals (Sweden)

    Di Saverio Salomone

    2011-01-01

    Full Text Available Abstract Emergency surgery of the small bowel represents a challenge for the surgeon, in the third millennium as well. There is a wide number of pathologies which involve the small bowel. The present review, by analyzing the recent and past literature, resumes the more commons. The aim of the present review is to provide the main indications to face the principal pathologies an emergency surgeon has to face with during his daily activity.

  10. The Immune System in Irritable Bowel Syndrome

    OpenAIRE

    Barbara, Giovanni; Cremon, Cesare; Carini, Giovanni; Bellacosa, Lara; Zecchi, Lisa; De Giorgio, Roberto; Corinaldesi, Roberto; Stanghellini, Vincenzo

    2011-01-01

    The potential relevance of systemic and gastrointestinal immune activation in the pathophysiology and symptom generation in the irritable bowel syndrome (IBS) is supported by a number of observations. Infectious gastroenteritis is the strongest risk factor for the development of IBS and increased rates of IBS-like symptoms have been detected in patients with inflammatory bowel disease in remission or in celiac disease patients on a gluten free diet. The number of T cells and mast cells in the...

  11. 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...

  12. Rheumatic manifestations of inflammatory bowel disease

    OpenAIRE

    Rodríguez-Reyna, Tatiana Sofía; Martínez-Reyes, Cynthia; Yamamoto-Furusho, Jesús Kazúo

    2009-01-01

    This article reviews the literature concerning rheumatic manifestations of inflammatory bowel disease (IBD), including common immune-mediated pathways, frequency, clinical course and therapy. Musculoskeletal complications are frequent and well-recognized manifestations in IBD, and affect up to 33% of patients with IBD. The strong link between the bowel and the osteo-articular system is suggested by many clinical and experimental observations, notably in HLA-B27 transgenic rats. The autoimmune...

  13. PYODERMA GANGRENOSUM WITH INFLAMATORY BOWEL DISEASE

    OpenAIRE

    Guru Prasad; Jhansi Lakshmi; Krishna Rao; Parvathi; Durga Bhavani

    2015-01-01

    Pyoderma gangrenosum (PG) is a chronic , painful ulcerated skin disease of unknown etiology. Its association with inflammatory bowel disease like ulcerative colitis is common . The lesions generally appear dur ing the course of active bowel disease , frequently concur with exacerbations of colitis , sometimes with inactive ulcerative colitis. 15 to 20 % of patients with Pyoderma gangrenosum have ulcerative colitis and 0.5 to 5 % of patients w...

  14. Feasibility of laparoscopy for small bowel obstruction

    OpenAIRE

    De Sol Angelo A; Migliaccio Carla; Delmonaco Pamela; Cattorini Lorenzo; Morelli Umberto; La Mura Francesco; Cirocchi Roberto; Farinella Eriberto; Cozzaglio Luca; Sciannameo Francesco

    2009-01-01

    Abstract Background Adherential pathology is the most common cause of small bowel obstruction. Laparoscopy in small bowel obstruction does not have a clear role yet; surely it doesn't always represent only a therapeutic act, but it is always a diagnostic act, which doesn't interfere with abdominal wall integrity. Methods We performed a review without any language restrictions considering international literature indexed from 1980 to 2007 in Medline, Embase and Cochrane Library. We analyzed th...

  15. Short Bowel Syndrome: A Case Report

    OpenAIRE

    Celayir, Sinan; Sarımurat, Nüvit; Ilıkkan, Barbaros; ERAY, Nur; Yeşildağ, Ebru; Yeker, Daver

    1996-01-01

    Necrotizing enterocolitis atresia volvulus gastroschisis are the most common causes of short bowel syndrome in the pediatric population Although the prognosis for patients with short bowel syndrome improved since the advent of parenteral nutrition the cost of long term total parenteral nutrition and attendant morbidity and mortality cannot be ignored in these patients Long term follow up of a case with short small intestine of 25 cm length following surgery is presented and the problems assoc...

  16. [Contemporary dietotherapy of the irritable bowel syndrome].

    Science.gov (United States)

    Pilipenko, V I; Burliaeva, E A; Isakov, V A

    2013-01-01

    Irritable bowel syndrome (IBS) is the most prevalent functional disease of the gastrointestinal tract. This highly prevalent condition is best diagnosed by assessing the constellation of symptoms with which patients present to their physicians. Because some critics have previously questioned whether irritable bowel syndrome and other functional gastrointestinal disorders truly exist because they do not have defining structural features, the Rome Foundation fostered the use of symptom-based criteria for universal use. In most cases treatment is reduced to symptomatic therapy because a lot of unknown in pathogenesis by irritable bowel syndrome. Irritable bowel syndrome leads to decrease of quality of life of the patients and could be one of the reasons of patients' disability. Food is believed by patients promotes symptoms and the diet or avoiding specific food can reduce symptoms. Possible role of different food and microbiota in the pathophysiology of irritable bowel syndrome, as well as the data from randomized, controlled clinical trials dedicated to the effects of diet in irritable bowel syndrome are summarized and discussed in this review. The efficacy of the diet, enriched by fiber, prebiotics, probiotics, peppermint oil, curcumin and vitamin B6 in irritable bowel syndrome patients was shown in numerous studies. In some studies restriction in consumption of fermented carbohydrates, coffee and alcohol, as well as diet with elimination IgG-sensed food was also shown to be effective in irritable bowel syndrome. Food intolerances, defined as non-toxic non-immune adverse reactions to food, include reactions to bioactive chemicals in foods and metabolic reactions to poorly absorbed dietary carbohydrates. New dietary approaches like polyunsaturated fatty acids intake correction and the low tryptophan intake are discussed. PMID:23808281

  17. A Case for Slow Reading

    Directory of Open Access Journals (Sweden)

    Matthew J Ostercamp

    2014-05-01

    Full Text Available This essay makes a case for the value of slow or deep reading.  Inspired by the Slow Food movement it seeks to apply their principles to reading.  It begins by exploring the meaning of information and how like food, information has come to be regarded as a commodity.  Drawing upon the philosophy of Albert Borgmann, it counters the prevalent commodity view of information by offering an alternative paradigm that connects careful reading to human flourishing.  It argues that by connecting information to pleasure and community, slow reading advocates can have comparable success to that enjoyed by the slow food movement.

  18. 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.)

  19. 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.

  20. 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...

  1. Etiopathogenesis of inflammatory bowel diseases

    Institute of Scientific and Technical Information of China (English)

    Silvio Danese; Claudio Fiocchi

    2006-01-01

    Theories explaining the etiopathogenesis of inflammatory bowel disease (IBD) have been proposed ever since Crohn's disease (CD) and ulcerative colitis (UC) were recognized as the two major forms of the disease. Although the exact cause(s) and mechanisms of tissue damage in CD and UC have yet to be completely understood, enough progress has occurred to accept the following hypothesis as valid: IBD is an inappropriate immune response that occurs in genetically susceptible individuals as the result of a complex interaction among environmental factors, microbial factors, and the intestinal immune system. Among an almost endless list of environmental factors, smoking has been identified as a risk factor for CD and a protective factor for UC. Among microbial factors, no convincing evidence indicates that classical infectious agents cause IBD, while mounting evidence points to an abnormal immune response against the normal enteric flora as being of central importance. Gut inflammation is mediated by cells of the innate as well as adaptive immune systems, with the additional contribution of non-immune cells, such as epithelial, mesenchymal and endothelial cells, and platelets.

  2. Pharmacogenetics in inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Marie Pierik; Paul Rutgeerts; Robert Vlietinck; Severine Vermeire

    2006-01-01

    Pharmacogenetics is the study of the association between variability in drug response and (or) drug toxicity and polymorphisms in genes. The goal of this field of science is to adapt drugs to a patient's specific genetic background and therefore make them more efficacious and safe. In this article we describe the variants in genes that influence either the efficacy or toxicity of common drugs used in the treatment of inflammatory bowel diseases (IBD), ulcerative colitis (UC),and Crohn's disease (CD) including sulfasalazine and mesalazine, azathioprine (AZA) and 6-mercaptopurine (6-MP), methotrexate (MTX), glucocorticosteroids (CSs) and infliximab. Furthermore, difficulties with pharmacogenetic studies in general and more specifically in IBD are described. Although pharmacogenetics is a promising field that already contributed to a better understanding of some of the underlying mechanisms of action of drugs used in IBD, the only discovery translated until now into daily practice is the relation between thiopurine S-methyltransferase (TPMT) gene polymorphisms and hematological toxicity of thiopurine treatment. In the future it is necessary to organize studies in well characterized patient cohorts who have been uniformly treated and systematically evaluated in order to quantitate drug response more objectively. An effort should be made to collect genomic DNA from all patients enrolled in clinical drug trials after appropriate informed consent for pharmacogenetic studies.

  3. Inflammatory bowel disease in pregnancy

    Institute of Scientific and Technical Information of China (English)

    Dawn B Beaulieu; Sunanda Kane

    2011-01-01

    Crohn's disease and ulcerative colitis affect women in their child-bearing years. Family planning has come to be a common discussion between the gastroenterologist and the inflammatory bowel disease (IBD) patient.Disease control prior to desired conception and throughout pregnancy is the most important thing to keep in mind when caring for the IBD patient. Continued medical management during pregnancy is crucial in optimizing outcomes. Studies indicate that quiescent disease prior to conception infer the best pregnancy outcomes, similar to those in the general population.Active disease prior to and during pregnancy, can lead to complications such as pre-term labor, low birth weight, and small for gestational age infants. Although there are no definitive long term effects of pregnancy on IBD, there are some limited studies that suggest that it may alter the disease course. Understanding the literature and its limitations is important in the modern era of IBD care. Educating the patient and taking a team approach with the obstetrician will help achieve successful outcomes for mother and baby.

  4. Smoking and inflammatory bowel disease.

    Science.gov (United States)

    Rubin, D T; Hanauer, S B

    2000-08-01

    It is well established that smoking cigarettes is associated with Crohn's disease (CD) and that non-smoking is associated with ulcerative colitis (UC). Furthermore, there is convincing evidence that smoking cigarettes has a negative effect on the course of CD, and that smoking cigarettes may improve the disease severity or have a 'protective' effect in some patients with UC. Despite these well-described associations, the mechanism by which cigarette smoking affects CD and UC is not known. Researchers have studied the systemic effects, cellular and humoral immune effects, mucosal changes, and the intestinal permeability changes with inflammatory bowel disease (IBD) and smoking. To date, none of these studies adequately explains the observed clinical patterns. It has been assumed that nicotine is the active agent in these associations, but clinical trials of nicotine chewing gum and transdermal nicotine in UC have shown limited benefit, and have been complicated by significant side-effects. Topical delivery systems for nicotine therapy are currently under development and await future clinical trials. PMID:10958212

  5. [Parasitosis and irritable bowel syndrome].

    Science.gov (United States)

    Ibarra, Catalina; Herrera, Valentina; Pérez de Arce, Edith; Gil, Luis Carlos; Madrid, Ana María; Valenzuela, Lucía; Beltrán, Caroll J

    2016-06-01

    Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract characterised by multi-factorial aetiology. In IBS physiopathology are involved diverse factors between them biological, psychosocial, and environmental components which affect the immune activation status of gut mucosa. Among these factors is recognized the intestinal parasitosis. Post-infection IBS (PI-IBS) is recognised as a subgroup of functional disorders whose symptoms onset appear after a symptomatic intestinal infection caused by microbial agents. There are few studies regarding of relationship between IBS and intestinal parasitosis in Chile. However, is has been well described a positive association between IBS and Blastocystis hominis infections, one of prevalent parasites in Chile. In other countries, is also described a relationship between IBS and amebiasis and giardiasis. Both, characterized by a common mode of transmission through water as well as contaminated food. Because the high prevalence of parasitosis in our country it is necessary to expand the association studies to clarify the strength of the parasites ethiology in IBS. PMID:27598274

  6. 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.)

  7. Feasibility of laparoscopy for small bowel obstruction

    Directory of Open Access Journals (Sweden)

    De Sol Angelo A

    2009-01-01

    Full Text Available Abstract Background Adherential pathology is the most common cause of small bowel obstruction. Laparoscopy in small bowel obstruction does not have a clear role yet; surely it doesn't always represent only a therapeutic act, but it is always a diagnostic act, which doesn't interfere with abdominal wall integrity. Methods We performed a review without any language restrictions considering international literature indexed from 1980 to 2007 in Medline, Embase and Cochrane Library. We analyzed the reference lists of the key manuscripts. We also added a review based on international non-indexed sources. Results The feasibility of diagnostic laparoscopy is high (60–100%, while that of therapeutic laparoscopy is low (40–88%. The frequency of laparotomic conversions is variable ranging from 0 to 52%, depending on patient selection and surgical skill. The first cause of laparotomic conversion is a difficult exposition and treatment of band adhesions. The incidence of laparotomic conversions is major in patients with anterior peritoneal band adhesions. Other main causes for laparotomic conversion are the presence of bowel necrosis and accidental enterotomies. The predictive factors for successful laparoscopic adhesiolysis are: number of previous laparotomies ≤ 2, non-median previous laparotomy, appendectomy as previous surgical treatment causing adherences, unique band adhesion as phatogenetic mechanism of small bowel obstruction, early laparoscopic management within 24 hours from the onset of symptoms, no signs of peritonitis on physical examination, experience of the surgeon. Conclusion Laparoscopic adhesiolysis in small bowel obstruction is feasible but can be convenient only if performed by skilled surgeons in selected patients. The laparoscopic adhesiolysis for small bowel obstruction is satisfactorily carried out when early indicated in patients with a low number of laparotomies resulting in a short hospital stay and a lower postoperative

  8. Slow Tourism: Exploring the discourses

    Directory of Open Access Journals (Sweden)

    J. Guiver

    2016-05-01

    Full Text Available ‘Slow travel’ and ‘slow tourism’ are relatively new, but contested, concepts. This paper examines the meanings ascribed to them in the academic literature and websites targeted at potential tourists. It finds concurrence on aspects of savouring time at the destination and investing time to appreciate the locality, its people, history, culture and products, but detects different emphases. The academic literature stresses the benefits to the destination and global sustainability, while the websites focus on the personal benefits and ways of becoming a ‘slow tourist’. Food and drink epitomise the immersion in and absorption of the destination and the multi-dimensional tourism experience, contrasted with the superficiality of mainstream tourism. The paper discusses whether tourists practising slow tourism without using the label are slow tourists or not.

  9. On the use of slow light for enhancing waveguide properties

    DEFF Research Database (Denmark)

    Mørk, Jesper; Nielsen, Torben Roland

    2010-01-01

    On the basis of a general analysis of waveguides containing a dispersive material, we identify conditions under which slow-light propagation may enhance the gain, absorption, or phase change. The enhancement is shown to depend on the slow-light mechanism and the translational symmetry of the wave...... waveguide. A combination of material and waveguide dispersion may strongly enhance the control of light speed, e.g., using electromagnetically induced transparency in quantum dots embedded in a photonic crystal waveguide.......On the basis of a general analysis of waveguides containing a dispersive material, we identify conditions under which slow-light propagation may enhance the gain, absorption, or phase change. The enhancement is shown to depend on the slow-light mechanism and the translational symmetry of the...

  10. Light and sound - emerging imaging techniques for inflammatory bowel disease.

    Science.gov (United States)

    Knieling, Ferdinand; Waldner, Maximilian J

    2016-07-01

    Patients with inflammatory bowel disease are known to have a high demand of recurrent evaluation for therapy and disease activity. Further, the risk of developing cancer during the disease progression is increasing from year to year. New, mostly non-radiant, quick to perform and quantitative methods are challenging, conventional endoscopy with biopsy as gold standard. Especially, new physical imaging approaches utilizing light and sound waves have facilitated the development of advanced functional and molecular modalities. Besides these advantages they hold the promise to predict personalized therapeutic responses and to spare frequent invasive procedures. Within this article we highlight their potential for initial diagnosis, assessment of disease activity and surveillance of cancer development in established techniques and recent advances such as wide-view full-spectrum endoscopy, chromoendoscopy, autofluorescence endoscopy, endocytoscopy, confocal laser endoscopy, multiphoton endoscopy, molecular imaging endoscopy, B-mode and Doppler ultrasound, contrast-enhanced ultrasound, ultrasound molecular imaging, and elastography. PMID:27433080

  11. Centrally driven slow oscillating potential of extrathoracic trachea.

    Science.gov (United States)

    Kondo, T; Kobayashi, I; Hirokawa, Y; Ohta, Y; Yamabayashi, H; Arita, H

    1993-03-01

    Spontaneous electrical activity of extrathoracic trachea was recorded along with force developed by tracheal smooth muscle and phrenic nerve activity in decerebrated, paralyzed, and artificially ventilated dogs with pneumothorax. The tracheal electrical activity exhibited slow oscillating potentials that were coupled with spontaneous phasic contraction of trachea. Both rhythmic changes were synchronous with central respiratory rhythm represented by phrenic burst, independent of the respirator's rhythm. The dominant component of the slow oscillating potentials consisted of sinusoidal waves with large amplitude that occurred shortly after cessation of phrenic burst, i.e., in the postinspiratory phase. The concomitant small change in the slow oscillating potentials began in the late inspiratory phase just before the initiation of the tracheal contraction. This phase relationship was preserved after removal of intrathoracic vagal afferents from lungs. Such slow oscillating potentials were also observed during lung collapse produced by disconnecting the tube attached to the respirator. Transection of recurrent laryngeal nerves abolished the slow oscillating potentials. These results indicate that the slow oscillating potentials of the extrathoracic trachea are generated by a physiological process associated with the central respiratory rhythm. The dominant component of the slow oscillating potentials occurs in the postinspiratory phase. PMID:8482644

  12. Fecal calprotectin in inflammatory bowel disease

    Directory of Open Access Journals (Sweden)

    Walsham NE

    2016-01-01

    Full Text Available Natalie E Walsham,1 Roy A Sherwood2 1Department of Clinical Biochemistry, University Hospital Lewisham, Lewisham, 2Department of Clinical Biochemistry, Viapath at King’s College Hospital NHS Foundation Trust, London, UK Abstract: Inflammatory bowel disease (IBD and irritable bowel syndrome share many symptoms. While irritable bowel syndrome is a functional bowel disorder for which no specific treatment is available, the range of effective therapies for IBD is evolving rapidly. Accurate diagnosis of IBD is therefore essential. Clinical assessment, together with various imaging modalities and endoscopy, has been the mainstay of diagnosis for many years. Fecal biomarkers of gastrointestinal inflammation have appeared in the past decade, of which calprotectin, a neutrophil cytosolic protein, has been studied the most. Crohn’s disease and ulcerative colitis are chronic remitting and relapsing diseases, and objective assessment of disease activity and response to treatment are important. This review focuses on the use of fecal calprotectin measurements in the diagnosis and monitoring of patients with IBD. Keywords: calprotectin, Crohn’s disease, ulcerative colitis, inflammatory bowel disease, inflammation 

  13. Biofeedback & Bowel Disorders: Teaching Yourself to Live without the Problem

    Science.gov (United States)

    ... Constipation Personal Stories Contact Us Biofeedback & Bowel Disorders: Teaching Yourself to Live Without the Problem Home Biofeedback ... donation. Adapted from IFFGD Publication: Biofeedback & Bowel Disorders: Teaching Yourself to Live without the Problem by Mary ...

  14. 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 co

  15. Cannabis for inflammatory bowel disease.

    Science.gov (United States)

    Naftali, Timna; Mechulam, Raphael; Lev, Lihi Bar; Konikoff, Fred M

    2014-01-01

    The marijuana plant Cannabis sativa has been used for centuries as a treatment for a variety of ailments. It contains over 60 different cannabinoid compounds. Studies have revealed that the endocannabinoid system is involved in almost all major immune events. Cannabinoids may, therefore, be beneficial in inflammatory disorders. In murine colitis, cannabinoids decrease histologic and microscopic inflammation. In humans, cannabis has been used to treat a plethora of gastrointestinal problems, including anorexia, emesis, abdominal pain, diarrhea, and diabetic gastroparesis. Despite anecdotal reports on medical cannabis in inflammatory bowel disease (IBD), there are few controlled studies. In an observational study in 30 patients with Crohn's disease (CD), we found that medical cannabis was associated with improvement in disease activity and reduction in the use of other medications. In a more recent placebo-controlled study in 21 chronic CD patients, we showed a decrease in the CD activity index >100 in 10 of 11 subjects on cannabis compared to 4 of 10 on placebo. Complete remission was achieved in 5 of 11 subjects in the cannabis group and 1 of 10 in the placebo group. Yet, in an additional study, low-dose cannabidiol did not have an effect on CD activity. In summary, evidence is gathering that manipulating the endocannabinoid system can have beneficial effects in IBD, but further research is required to declare cannabinoids a medicine. We need to establish the specific cannabinoids, as well as appropriate medical conditions, optimal dose, and mode of administration, to maximize the beneficial effects while avoiding any potential harmful effects of cannabinoid use. PMID:24969296

  16. Jejunitis and brown bowel syndrome with multifocal carcinogenesis of the small bowel.

    Science.gov (United States)

    Raithel, Martin; Rau, Tilman T; Hagel, Alexander F; Albrecht, Heinz; de Rossi, Thomas; Kirchner, Thomas; Hahn, Eckhart G

    2015-09-28

    This is the first report describing a case where prolonged, severe malabsorption from brown bowel syndrome progressed to multifocally spread small bowel adenocarcinoma. This case involves a female patient who was initially diagnosed with chronic jejunitis associated with primary diffuse lymphangiectasia at the age of 26 years. The course of the disease was clinically, endoscopically, and histologically followed for 21 years until her death at the age 47 due to multifocal, metastasizing adenocarcinoma of the small bowel. Multiple lipofuscin deposits (so-called brown bowel syndrome) and severe jejunitis were observed microscopically, and sections of the small bowel showed dense lymphoplasmacytic infiltration of the lamina propria as well as blocked lymphatic vessels. After several decades, multifocal nests of adenocarcinoma cells and extensive, flat, neoplastic mucosal proliferations were found only in the small bowel, along with a loss of the mismatch repair protein MLH1 as a long-term consequence of chronic jejunitis with malabsorption. No evidence was found for hereditary nonpolyposis colon carcinoma syndrome. This article demonstrates for the first time multifocal carcinogenesis in the small bowel in a malabsorption syndrome in an enteritis-dysplasia-carcinoma sequence. PMID:26420973

  17. Slow dynamics and correlation functions

    OpenAIRE

    Halpern, V.

    2006-01-01

    The slow dynamics of a system as it approaches a phase transition, associated with the slowing down in the decay of a correlation function, can be caused by a sharp increase in the probability of a particle's returning to its original state following a transition, rather than to a slowing down in the transition rates as is usually assumed. The results of our calculations show that this is the case for the ferromagnetic Potts model. The implications of this result for various theories of the g...

  18. The role of fecal calprotectin in investigating inflammatory bowel diseases

    OpenAIRE

    Mustafa Erbayrak; Cansel Turkay; Elife Eraslan; Hulya Cetinkaya; Benan Kasapoglu; Mehmet Bektas

    2009-01-01

    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 outpatie...

  19. Transient small bowel angioedema due to intravenous iodinated contrast media

    OpenAIRE

    Hu, Xiu-Hua; Gong, Xiang-Yang; Hu, Peng

    2012-01-01

    Three cases of transient proximal small bowel angioedema induced by intravenous administration of nonionic iodinated contrast media (CM) are presented. Computed tomography (CT) images in the venous phase displayed the proximal small bowel with circumferential thickening of the wall including the duodenum and proximal segment of the jejunum. The bowel wall was normal in non-enhanced images, and normal or inconspicuous in arterial phase enhanced images. In one of the three cases, the bowel wall...

  20. 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.

  1. Small-bowel permeability in collagenous colitis

    DEFF Research Database (Denmark)

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

    2006-01-01

    -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. MATERIAL AND METHODS: Ten patients with CC and chronic diarrhoea participated in the study. Coeliac disease was excluded by small-bowel biopsy and/or serology. Intestinal permeability was assessed as urinary excretion (ratios) 2, 4 and 6 h after ingestion of 14C-labelled mannitol (14C......: No alterations in intestinal permeability in patients with CC could be demonstrated. Impairment of the integrity of the mucosa of the small bowel and the presence of a general dysfunction of the small intestine in patients with CC seem unlikely....

  2. Laparoscopic Management of Adhesive Small Bowel Obstruction

    Science.gov (United States)

    Konjic, Ferid; Idrizovic, Enes; Hasukic, Ismar; Jahic, Alen

    2016-01-01

    Introduction: Adhesions are the reason for bowel obstruction in 80% of the cases. In well selected patients the adhesive ileus laparoscopic treatment has multiple advantages which include the shorter hospitalization period, earlier food taking, and less postoperative morbidity rate. Case report: Here we have a patient in the age of 35 hospitalized at the clinic due to occlusive symptoms. Two years before an opened appendectomy had been performed on him. He underwent the treatment of exploration laparoscopy and laparoscopic adhesiolysis. Dilated small bowel loops connected with the anterior abdominal wall in the ileocecal region by adhesions were found intraoperatively and then resected harmonically with scalpel. One strangulation around which a small bowel loop was wrapped around was found and dissected. Postoperative course was normal. PMID:27041815

  3. Small Bowel Obstruction Due to Suprapubic Catheter Placement

    OpenAIRE

    Bonasso, Patrick C.; Brandon Lucke-Wold; Uzer Khan

    2016-01-01

    Suprapubic catheter placement has associated complications such as bowel injury, bladder injury, or bleeding. This case describes the management of an elderly patient who had suprapubic catheter placement complicated by small bowel obstruction. The catheter had continued production of urine. Further patient treatment required abdominal exploration and bowel resection.

  4. Small Bowel Obstruction Due to Suprapubic Catheter Placement

    Directory of Open Access Journals (Sweden)

    Patrick C. Bonasso

    2016-07-01

    Full Text Available Suprapubic catheter placement has associated complications such as bowel injury, bladder injury, or bleeding. This case describes the management of an elderly patient who had suprapubic catheter placement complicated by small bowel obstruction. The catheter had continued production of urine. Further patient treatment required abdominal exploration and bowel resection.

  5. Small Bowel Obstruction Due to Suprapubic Catheter Placement.

    Science.gov (United States)

    Bonasso, Patrick C; Lucke-Wold, Brandon; Khan, Uzer

    2016-07-01

    Suprapubic catheter placement has associated complications such as bowel injury, bladder injury, or bleeding. This case describes the management of an elderly patient who had suprapubic catheter placement complicated by small bowel obstruction. The catheter had continued production of urine. Further patient treatment required abdominal exploration and bowel resection. PMID:27335801

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

    International Nuclear Information System (INIS)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hyun Suk; Woo, Ji Young; Hong, Hye Suk; Park, Mee Hyun; Yang, Ik; Lee, Yul; Jung, Ah Young; Hwang, Ji Young [Dept. of Radiology, Hallym University College of Medicine, Kangnam Sacred Heart Hospital, Seoul (Korea, Republic of); Ha, Hong Il [Dept. of Radiology, Hallym University College of Medicine, Hallym University Sacred Heart Hospital, Anyang (Korea, Republic of)

    2013-08-15

    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.

  8. Microwave photonics: Harnessing slow light

    OpenAIRE

    Capmany J.; Gasulla I.; Sales S.

    2011-01-01

    Slow-light techniques originally conceived for buffering high-speed digital optical signals now look set to play an important role in providing broadband phase and true time delays for microwave signals.

  9. Delayed bowel perforation following suprapubic catheter insertion

    Directory of Open Access Journals (Sweden)

    Mehta Ajay

    2004-12-01

    Full Text Available Abstract Background Complications of suprapubic catheter insertion are rare but can be significant. We describe an unusual complication of a delayed bowel perforation following suprapubic catheter insertion. Case presentation A gentleman presented with features of peritonitis and feculent discharge along a suprapubic catheter two months after insertion of the catheter. Conclusion Bowel perforation is the most feared complication of suprapubic catheter insertion especially in patients with lower abdominal scar. The risk may be reduced with the use of ultrasound scan guidance.

  10. Case report: Congenital short bowel syndrome

    Directory of Open Access Journals (Sweden)

    Palle Lalitha

    2010-01-01

    Full Text Available Congenital short bowel syndrome (SBS is a relatively rare condition as compared to acquired SBS. It is associated with significant mortality and morbidity. Infants usually present with failure to thrive, recurrent vomiting, and diarrhea. It is important to suspect and diagnose this condition promptly, as early initiation of parenteral nutrition or surgery, if necessary, may result in a favorable outcome. We discuss a case of an infant aged 26 days, who presented with failure to thrive, recurrent vomiting, and weight loss. A contrast study of the gastrointestinal tract revealed a short small bowel, with malrotation. The infant was started on parenteral nutrition, but succumbed shortly thereafter to severe disseminated sepsis.

  11. Cold and Slow Molecular Beam

    OpenAIRE

    Rasmussen, Julia; Patterson, Dave; Lu, Hsin-I; Wright, Matthew; Doyle, John M.

    2011-01-01

    Employing a two-stage cryogenic buffer gas cell, we produce a cold, hydrodynamically extracted beam of calcium monohydride molecules with a near effusive velocity distribution. Beam dynamics, thermalization and slowing are studied using laser spectroscopy. The key to this hybrid, effusive-like beam source is a “slowing cell” placed immediately after a hydrodynamic, cryogenic source [Patterson et al., J. Chem. Phys., 2007, 126, 154307]. The resulting CaH beams are created in two regimes. In on...

  12. Slow Neutron Scattering by Benzene

    International Nuclear Information System (INIS)

    We have calculated the scattering of slow neutrons by the benzene molecule. The calculations are carried out within the framework of the time dependent formalism of Zemach and Glauber. Detailed account is taken of the effects of the molecular vibrations on the neutron scattering. Among the results explicitly calculated are the slow neutron total scattering cross-section as a function of energy and the energy angular distribution of singly scattered sections. (author)

  13. Slow motion increases perceived intent.

    Science.gov (United States)

    Caruso, Eugene M; Burns, Zachary C; Converse, Benjamin A

    2016-08-16

    To determine the appropriate punishment for a harmful action, people must often make inferences about the transgressor's intent. In courtrooms and popular media, such inferences increasingly rely on video evidence, which is often played in "slow motion." Four experiments (n = 1,610) involving real surveillance footage from a murder or broadcast replays of violent contact in professional football demonstrate that viewing an action in slow motion, compared with regular speed, can cause viewers to perceive an action as more intentional. This slow motion intentionality bias occurred, in part, because slow motion video caused participants to feel like the actor had more time to act, even when they knew how much clock time had actually elapsed. Four additional experiments (n = 2,737) reveal that allowing viewers to see both regular speed and slow motion replay mitigates the bias, but does not eliminate it. We conclude that an empirical understanding of the effect of slow motion on mental state attribution should inform the life-or-death decisions that are currently based on tacit assumptions about the objectivity of human perception. PMID:27482091

  14. Laboratory observations of slow earthquakes and the spectrum of tectonic fault slip modes.

    Science.gov (United States)

    Leeman, J R; Saffer, D M; Scuderi, M M; Marone, C

    2016-01-01

    Slow earthquakes represent an important conundrum in earthquake physics. While regular earthquakes are catastrophic events with rupture velocities governed by elastic wave speed, the processes that underlie slow fault slip phenomena, including recent discoveries of tremor, slow-slip and low-frequency earthquakes, are less understood. Theoretical models and sparse laboratory observations have provided insights, but the physics of slow fault rupture remain enigmatic. Here we report on laboratory observations that illuminate the mechanics of slow-slip phenomena. We show that a spectrum of slow-slip behaviours arises near the threshold between stable and unstable failure, and is governed by frictional dynamics via the interplay of fault frictional properties, effective normal stress and the elastic stiffness of the surrounding material. This generalizable frictional mechanism may act in concert with other hypothesized processes that damp dynamic ruptures, and is consistent with the broad range of geologic environments where slow earthquakes are observed. PMID:27029996

  15. Fecal lactoferrin in discriminating inflammatory bowel disease from Irritable bowel syndrome: a diagnostic meta-analysis

    OpenAIRE

    Zhou, Xing-lu; Xu, Wen; Tang, Xiao-xiao; Luo, Lai-sheng; Tu, Jiang-feng; Zhang, Chen-jing; Xu, Xiang; Wu, Qin-dong; Pan, Wen-Sheng

    2014-01-01

    Background To perform a meta-analysis evaluating the diagnostic ability of fecal lactoferrin (FL) to distinguish inflammatory bowel disease (IBD) from irritable bowel syndrome (IBS). Methods The Medline, EMBASE, Web of Science, Cochrane library and CNKI databases were systematically searched for studies that used FL concentrations to distinguish between IBD and IBS. The sensitivity, specificity, and other diagnostic indexes of FL were pooled using a random-effects model. Results Seven studies...

  16. Quantitative Risk-Benefit Analysis of Probiotic Use for Irritable Bowel Syndrome and Inflammatory Bowel Disease.

    Science.gov (United States)

    Bennett, William E

    2016-04-01

    Probiotics have seen widespread use for a variety of gastrointestinal problems, especially in two common disorders: irritable bowel syndrome and inflammatory bowel disease. Since a wide variety of probiotic preparations has been used, and despite a large number of studies performed, a great deal of heterogeneity exists among them. Straightforward evidence-based recommendations for the use of probiotics in irritable bowel syndrome and inflammatory bowel disease have thus been difficult to formulate. In an effort to improve understanding of the risk-benefit balance of probiotics in these conditions, this study (1) queried the US FDA Adverse Event Reporting System (FAERS) database for all reported adverse drug events related to probiotics in 2013, and (2) constructed risk-benefit planes for both irritable bowel syndrome and inflammatory bowel disease using a geometric approximation of the confidence region between risk and benefit. The results show that adverse events from probiotics vary widely by disease, and when they occur, they are mild and may be difficult to distinguish from the natural history of the underlying disorders they are used to treat. The risk-benefit plane for irritable bowel syndrome straddles the risk-benefit threshold, so patients can expect a balance between a low chance of risk and also a low chance of benefit. The risk-benefit plane for inflammatory bowel disease largely lies above the risk-benefit threshold, so patients may expect more benefit than risk in most cases. More standardized and high-quality research is needed to improve our understanding of risk and benefit for these complex biopharmaceuticals. PMID:26467550

  17. Endoscopic Evaluation of Surgically Altered Bowel in Patients with Inflammatory Bowel Diseases

    OpenAIRE

    Sinh, Preetika; Shen, Bo

    2015-01-01

    Abstract: Patients with inflammatory bowel diseases often undergo surgical procedures for medically refractory disease or colitis associated dysplasia. Endoscopic evaluation of the surgically altered bowel is often needed to assess for disease recurrence, its severity, and for therapy. It is important to obtain and review the operative report and abdominal imaging before performing the endoscopy. Diagnostic and therapeutic endoscopy can be safely performed in most patients with inflammatory b...

  18. 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.

  19. New pharmaceuticals in inflammatory bowel disease

    OpenAIRE

    Łodyga, Michał; Eder, Piotr; Bartnik, Witold; Gonciarz, Maciej; Kłopocka, Maria; Linke, Krzysztof; Małecka-Panas, Ewa; Radwan, Piotr; Rydzewska, Grażyna

    2015-01-01

    This paper complements the previously published Guidelines of the Working Group of the Polish Society of Gastroenterology and former National Consultant in Gastroenterology regarding the management of patients with Crohn's disease and ulcerative colitis. Attention was focused on the new pharmaceutical recently registered for inflammatory bowel disease treatment.

  20. Unusual causes of mechanical small bowel obstruction

    International Nuclear Information System (INIS)

    We herein report our experience regarding unusual causes of bowel obstruction to increase the awareness of surgeons regarding this disease. From 1991 to 2003, we had experience at the University affiliated hospitals, northern Jordan with 24 patients with small bowel obstruction resulting from unusual causes. We retrospectively reviewed the medical records of these patients with regards to the mode of presentation, cause of obstruction, radiological and operative findings, management and outcome. We recorded 15 patients who underwent previous abdominal surgery. Preoperative diagnosis was correct in only one patient with an internal hernia, but the abdominal CT scan suggested the diagnosis in 5 of the 9 patients who had the scan. The final diagnosis was internal hernias in 11 patients, foreign bodies in 5, ischemic strictures in 3, carcinoid tumors in 2, endometriosis in 2, and metastatic deposit from interstitial bladder carcinoma in one patient. Nine of the 12 patients with recurrent obstruction had either short course or recurrence obstruction during the same hospital admission. W carried out bowel resections in 15 patients (5 resections were due to bowel strangulation). Post operative death occurred in 4 patients. Awareness of these rare causes of intestinal obstruction even in patients with previous abdominal operation might improve the outcome. The tentative diagnosis of adhesion obstruction in patients with unusual obstructive etiology might lead to a higher rate of gangrenous complications. Rigorous preoperative evaluation including careful history and early abdominal CT may show the obstructive cause. (author)

  1. Inflammatory bowel disease: potential therapeutic strategies

    DEFF Research Database (Denmark)

    Nielsen, O H; Vainer, B; Bregenholt, S;

    1997-01-01

    This review deals with potential and possibly primary therapeutics that, through insight into the inflammatory cascade, result in more rational treatment principles replacing the classical therapy of inflammatory bowel disease (IBD), i.e. Crohn's disease (CD) and ulcerative colitis (UC). These new...

  2. Small-bowel permeability in collagenous colitis

    DEFF Research Database (Denmark)

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

    2006-01-01

    , 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....

  3. Environmental factors in inflammatory bowel disease

    DEFF Research Database (Denmark)

    Hansen, Tanja Stenbaek; Jess, Tine; Vind, Ida;

    2011-01-01

    The role of environmental factors in development of inflammatory bowel disease (IBD) remains uncertain. The aim of the present study was to assess a number of formerly suggested environmental factors in a case-control study of an unselected and recently diagnosed group of patients with IBD and a...

  4. A rare cause of small bowel infarction

    OpenAIRE

    Lim, L.; Collier, K; Harland, R; Temperley, D

    2011-01-01

    We report a rare case of small bowel infarction due to superior mesenteric artery occlusion secondary to cardiac tumour embolism. To our knowledge, this has not been previously reported in the literature. This case highlights a rare case and reviews current knowledge on the subject.

  5. Recovery After Stroke: Bladder and Bowel Function

    Science.gov (United States)

    ... effects from prescription drugs.  Being unaware that you need to use the bathroom.  Weakness in the muscle that holds a bowel ... toilet  Occupational therapists can help if your home needs to be ... issues. They can with grants to adapt the bathroom or to build a new one, and can ...

  6. Microbiota biodiversity in inflammatory bowel disease

    OpenAIRE

    Comito, Donatella; Cascio, Antonio; Romano, Claudio

    2014-01-01

    Gut microbiota plays a significant role in human health and energy balance, and provides protection against disease states. An altered balance between microbiota and its host (dysbiosis) would appear to contribute to the development of Inflammatory Bowel Disease (IBD), Crohn’s Disease (CD) and Ulcerative Colitis (UC). CD and UC are chronic inflammatory diseases of the gastrointestinal tes.

  7. Analysis of bowel perforation in necrotizing enterocolitis

    Energy Technology Data Exchange (ETDEWEB)

    Frey, E.E.; Smith, W.; Franken, E.A. Jr.; Wintermeyer, K.A.

    1987-07-01

    The most severe complication of necrotizing enterocolitis (NEC) is bowel perforation. Identification of neonates at high risk for perforation and optimization of radiologic imaging to identify bowel perforation are necessary to reduce the high mortality rate associated with this catastrophic event. One hundred 55 cases of NEC were seen at our institution during a 5.5 year period. Nineteen (12%) progressed to perforation. A review of surgical findings, autopsy results and radiographs from these patients shows only 63% had radiographic evidence of free air in the peritoneal cavity at the time of perforation. Twenty-one percent had radiographic evidence of ascites but no pneumoperitoneum, and 16 percent had neither free air nor ascites. Thus purely radiographic criteria for bowel perforation in NEC are imprecise, and paracentesis is mandatory in NEC patients with ascites or clinical findings indicative of peritonitis. Timing of radiographic studies and site of bowel involvement are also important. Seventy-nine percent of perforations occurred by 30 h from confirmation of diagnosis (by clinical or radiographic criteria). Surgery or autopsy revealed involvement of the ileo-cecal region in 89% of cases with the actual site of perforation occurring in this area in 58% of patients.

  8. ARMA-based spectral bandwidth for evaluation of bowel motility by the analysis of bowel sounds

    International Nuclear Information System (INIS)

    Approximately 10%–20% of adults and adolescents suffer from irritable bowel syndrome (IBS) worldwide. IBS is characterized by chronic gastrointestinal dysfunction which may reflect in altered motility. Currently, the diagnosis of IBS is made through expensive invasive radiographic and endoscopic examinations. However these are inconvenient and unsuited for community screening. Bowel sounds (BSs) can be easily recorded with non-invasive and low-cost equipment. Recently, several researchers have pointed out changes in features obtained from BS according to the pathological condition of bowel motility. However a widely accepted, simple automatic BS detection algorithm still has to be found, and the appropriate recording period needs to be investigated for further evaluation of bowel motility. In this study we propose a novel simple automatic method to detect the BSs based on the 3 dB bandwidth of the frequency peaks in the autoregressive moving average spectrum. We use the measure, sound-to-sound interval (SSI) obtained by the proposed method, to capture bowel motility. In this paper, we show that the proposed method for automatic detection could achieve a sensitivity of 87.8±5.88%, specificity of 91.7±4.33% and area under the curve of 0.923 when working on 16 healthy volunteers during mosapride administrations. Furthermore, we show that the measured SSI averaged over a period of 30 min can clearly capture bowel motility. Our findings should have the potential to contribute toward developing automated BS-based diagnosis of IBS. (paper)

  9. Slow, stopped and stored light

    International Nuclear Information System (INIS)

    Light that can been slowed to walking pace could have applications in telecommunications, optical storage and quantum computing. Whether we use it to estimate how far away a thunderstorm is, or simply take it for granted that we can have a conversation with someone on the other side of the world, we all know that light travels extremely fast. Indeed, special relativity teaches us that nothing in the universe can ever move faster than the speed of light in a vacuum: 299 792 458 ms-1. However, there is no such limitation on how slowly light can travel. For the last few years, researchers have been routinely slowing light to just a few metres per second, and have recently even stopped it dead in its tracks so that it can be stored for future use. Slow-light has considerable popular appeal, deriving perhaps from the importance of the speed of light in relativity and cosmology. If everyday objects such as cars or people can travel faster than 'slow' light, for example, then it might appear that relativistic effects could be observed at very low speeds. Although this is not the case, slow light nonetheless promises to play an important role in optical technology because it allows light to be delayed for any period of time desired. This could lead to all-optical routers that would increase the bandwidth of the Internet, and applications in optical data storage, quantum information and even radar. (U.K.)

  10. CT findings of bowel injury following blunt abdominal trauma

    International Nuclear Information System (INIS)

    To determine the diagnostic value of CT, the author retrospectively reviewed preoperative CT findings of 57 cases with surgically proven bowel injury following blunt trauma. The small bowel injuries were divided into two groups, i.e., those without mesenteric injury, group A, and those with mesenteric injury, group B. The incidence of CT findings including extraluminal air, bowel wall thickening, peritoneal fluid, mesenteric thickening, and high density hematoma, were determined. CT findings were also assessed by time intervals between injury and examination. CT scans of small bowel injury were compared with those of surgically proven 25 cases of mesenteric injury without bowel injury, group C. CT showed findings suggestive of bowel injury in 96.4% of the cases. There were 5 false negative CT scans, which consisted of 4 small bowel and one large bowel injuries, all performed within 2 hours from injury. The patients in group A small bowel injury had a higher incidence of pneumoperitoneum on CT scans performed over 4 hours after injury than on those performed within 4 hours. Bowel wall thickening was more frequent in group A than in group B or C. Peritoneal fluid collection within 4 hours from injury was less frequent in group A than in group B or C. High density hematoma was more frequent in group B and C than in group A. The analysis suggested that early diagnosis of isolated small bowel injury was difficult because of lack of signs indicating mesenteric injury. In these cases bowel wall thickening appeared earlier, then peritoneal fluid developed, with and without mesenteric thickening or extraluminal air. Thus in those with suspicion of bowel injury, bowel wall thickening on initial CT should be carefully followed up in regard to additional or progressive findings. Operative indication can be determined with careful clinical correlation before detection of extraluminal air. (K.H.)

  11. Theory of carrier depletion and light amplification in active slow light photonic crystal waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2013-01-01

    Using a perturbative approach, we perform a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguide. The impact of slow-light propagation on the carrier-depletion-induced nonlinear gain saturation of the...... device is investigated. An effective rate-equation-based model is presented. It is shown that it well accounts for the three-dimensional simulation results. Simulations indicate that a slow-light-enhanced photonic crystal traveling-wave amplifier has a high small-signal modal gain and low saturation...

  12. MHD waves in sunspots

    CERN Document Server

    Sych, Robert

    2015-01-01

    The review addresses the spatial frequency morphology of sources of sunspot oscillations and waves, including their localization, size, oscillation periods, height localization with the mechanism of cut-off frequency that forms the observed emission variability. Dynamic of sunspot wave processes, provides the information about the structure of wave fronts and their time variations, investigates the oscillation frequency transformation depending on the wave energy is shown. The initializing solar flares caused by trigger agents like magnetoacoustic waves, accelerated particle beams, and shocks are discussed. Special attention is paid to the relation between the flare reconnection periodic initialization and the dynamics of sunspot slow magnetoacoustic waves. A short review of theoretical models of sunspot oscillations is provided.

  13. Slow light with electromagnetically induced transparency in optical fibre

    Science.gov (United States)

    Muhamad Hatta, Agus; Kamli, Ali A.; Al-Hagan, Ola A.; Moiseev, Sergey A.

    2015-08-01

    Slow light with electromagnetically induced transparency (EIT) in the core of optical fibre containing three-level atoms is investigated. The guided modes are treated in the weakly guiding approximation which renders the analysis into a manageable form. The transparency window and permittivity profile of the core due to the strong pump field in the EIT scheme is calculated. For a specific permittivity profile of the core due to EIT, the propagation constant of the weak signal field and spatial shape of fundamental guided mode are calculated by solving the vector wave equation using the finite difference method. It is found that the transparency window and slow light field can be controlled via the optical fibre parameters. The reduced group velocity of slow light in this configuration is useful for many technological applications such as optical memories, effective control of single photon fields, optical buffers and delay lines.

  14. Magnetoacoustic Waves in the Solar Stratified Atmosphere

    Institute of Scientific and Technical Information of China (English)

    郑惠南; 王水; 吴式灿; 李波

    2001-01-01

    The propagation of magnetoacoustic waves in the solar atmosphere consisting of the photosphere, chromosphere and corona has been studied numerically by time-dependent multi-dimensional magnetohydrodynamic (MHD) simulation. Pressure disturbances are introduced at the bottom of the chromosphere and at the bottom of the corona, respectively. The computational results show that incurred fast and slow MHD waves propagate away from the source of the disturbances. The fast MHD wave propagates as an expansive wave in the radial direction, while the slow one steepens and it may evolve into a slow shock. We suggest that the extreme ultraviolet imaging telescope wave observed by the SOHO and Moreton wave are a fast MHD wave propagating in the corona and in the chromosphere, respectively.

  15. Current drive by synergy of slow modes in tokamaks

    International Nuclear Information System (INIS)

    Enhancement of lower hybrid current drive in the presence of wave converted ion-ion slow modes is discussed using a one-dimensional quasi-linear equation. The special case in which the slow mode resulting from conversion in a deuterium-hydrogen mixture is absorbed by low energy electrons is considered in detail. In this scheme, the effect of the ion-ion modes is to increase the electron tail density, and the current enhancement is given by the ratio of the parallel velocity distributions with and without mode converted slow modes, calculated at the lower pparallel limit of the lower hybrid (LH) tail. The method of synergy is suited for remote control of the LH fast tail population, and is useful for current drive optimization. The computation also gives some insight into current drive by ion-ion slow modes in the absence of LH waves, a situation of relevance in a high temperature plasma where LH accessibility is severely reduced. (author). 8 refs, 5 figs

  16. Numerical modeling of slow shocks

    International Nuclear Information System (INIS)

    This paper reviews previous attempt and the present status of efforts to understand the structure of slow shocks by means of time dependent numerical calculations. Studies carried out using MHD or hybrid-kinetic codes have demonstrated qualitative agreement with theory. A number of unresolved issues related to hybrid simulations of the internal shock structure are discussed in some detail. 43 refs., 8 figs

  17. The dynamics of slow manifolds

    NARCIS (Netherlands)

    Verhulst, F.; Bakri, T.

    2006-01-01

    Invited lecture at Konferensi Nasional Matematika XIII, Semarang, 24-27 juli, 2006; to be publ. in J. Indones. Math. Soc. (2007) After reviewing a number of results from geometric singular perturbation theory, we discuss several approaches to obtain periodic solutions in a slow manifold. Regarding n

  18. 3D Coronal Slow Modes: Towards 3D Seismology

    OpenAIRE

    Marsh, M. S.; Walsh, R. W.; Plunkett, S.

    2009-01-01

    On 2008 January 10, the twin Solar Terrestrial Relations Observatory (STEREO) A and B spacecraft conducted a high time cadence study of the solar corona with the Extreme UltraViolet Imager (EUVI) instruments with the aim of investigating coronal dynamics. Observations of the three-dimensional propagation of waves within active region coronal loops and a measurement of the true coronal slow mode speed are obtained. Intensity oscillations with a period of approximately 12 minutes are observed t...

  19. Use of biosimilars in inflammatory bowel disease: Statements of the Italian Group for Inflammatory Bowel Disease.

    Science.gov (United States)

    Annese, Vito; Vecchi, Maurizio

    2014-11-01

    The introduction of biological therapies, particularly anti-TNFα agents, has revolutionized the management of inflammatory bowel disease in those cases which are refractory to conventional treatment; however these drugs are not risk-free and their use has substantially increased the cost of treatment. As marketing protection expires for original, first-generation biopharmaceuticals, lower-cost "copies" of these drugs produced by competitor companies-referred to as biosimilars-are already entering the market. In September 2013, the European Medicines Agency approved two infliximab biosimilars for treatment of adult and paediatric inflammatory bowel disease patients, a decision based largely on efficacy and safety data generated in studies of patients with ankylosing spondylitis and rheumatoid arthritis. For many clinicians, extrapolation practices and the general question of interchangeability between biosimilars and reference biologics are cause for concern. In the present paper, the Italian Group for inflammatory bowel disease presents its statements on these issues, with emphasis on the peculiar clinical characteristics of inflammatory bowel disease and the importance of providing physicians and patients with adequate information and guarantees on the safety and efficacy of these new drugs in the specific setting of inflammatory bowel disease. PMID:25139379

  20. The unappreciated slowness of conventional tourism

    Directory of Open Access Journals (Sweden)

    G.R. Larsen

    2016-05-01

    Full Text Available Most tourists are not consciously engaging in ‘slow travel’, but a number of travel behaviours displayed by conventional tourists can be interpreted as slow travel behaviour. Based on Danish tourists’ engagement with the distances they travel across to reach their holiday destination, this paper explores unintended slow travel behaviours displayed by these tourists. None of the tourists participating in this research were consciously doing ‘slow travel’, and yet some of their most valued holiday memories are linked to slow travel behaviours. Based on the analysis of these unintended slow travel behaviours, this paper will discuss the potential this insight might hold for promotion of slow travel. If unappreciated and unintentional slow travel behaviours could be utilised in the deliberate effort of encouraging more people to travel slow, ‘slow travel’ will be in a better position to become integrated into conventional travel behaviour.

  1. Beam interactions with surface waves and higher-order modes in oversized backward wave oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Ogura, Kazuo; Kojima, Akihiko; Kawabe, Fumiaki; Yambe, Kiyoyuki [Niigata University, Niigata (Japan); Amin, Ruhul [Islamic University of Technology, Gazipur (Bangladesh)

    2014-10-15

    Beam interactions with surface waves and higher-order modes in an oversized backward wave oscillator (BWO) are studied. In addition to the well-known Cherenkov interaction, the slow cyclotron interaction occurs due to transverse perturbations of the electron beam. The Cherenkov interaction dominates the slow cyclotron interaction. Growth rates of both the interactions for the higher order modes are small compared with those for the surface-wave modes in an oversized BWO. The coaxial slow-wave structure exhibits a reduced number of higher-order modes, which consequently reduces the mode competition problem and improves beam interactions with higher order modes. For higher values of beam currents, the slow cyclotron wave grows at a faster rate than the Cherenkov waves.

  2. Leukocyte migration in experimental inflammatory bowel disease

    Directory of Open Access Journals (Sweden)

    E. P. Van Rees

    1997-01-01

    Full Text Available Emigration of leukocytes from the circulation into tissue by transendothelial migration, is mediated subsequently by adhesion molecules such as selectins, chemokines and integrins. This multistep paradigm, with multiple molecular choices at each step, provides a diversity in signals. The influx of neutrophils, monocytes and lymphocytes into inflamed tissue is important in the pathogenesis of chronic inflammatory bowel disease. The importance of each of these groups of adhesion molecules in chronic inflammatory bowel disease, either in human disease or in animal models, will be discussed below. Furthermore, the possibilities of blocking these different steps in the process of leukocyte extravasation in an attempt to prevent further tissue damage, will be taken into account.

  3. Confocal Laser Endomicroscopy in Inflammatory Bowel Disease

    DEFF Research Database (Denmark)

    Rasmussen, Ditlev Nytoft; Karstensen, John Gásdal; Riis, Lene Buhl;

    2015-01-01

    BACKGROUND AND AIMS: Confocal laser endomicroscopy is an endoscopic method that provides in vivo real-time imaging of the mucosa at a cellular level, elucidating mucosal changes that are undetectable by white light endoscopy. This paper systematically reviews current indications and perspectives...... 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...... 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...

  4. Diet and risk of inflammatory bowel disease

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Olsen, Anja; Carbonnel, Franck;

    2012-01-01

    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...... dioxide and aluminium silicate). Conclusions: A diet high in protein, particular animal protein, may be associated with increased risk of inflammatory bowel disease and relapses. N-6 polyunsaturated fatty acids may predispose to ulcerative colitis whilst n-3 polyunsaturated fatty acid may protect. These...... results should be confirmed in other countries and in younger subjects before dietary counselling is recommended in high risk subjects....

  5. Imaging of inflammatory bowel disease. How?

    International Nuclear Information System (INIS)

    Traditionally the small bowel (barium) follow through (SBFT) has been the investigation of choice for that otherwise inaccessible length of gut between the duodenum and the ileocaecal valve. Whilst it is still a widely practised examination by radiologists it is being largely overtaken by other imaging modalities with CT, MRI and capsule endoscopy (CE) all competing for the territory. At the end of the last century, proponents of enteroclysis were predicting the eventual decline of the SBFT (in adults) although at that stage, in a 'state of the art' article, they were still brave enough to say that 'only in the small bowel does barium radiography remain unchallenged'. The same authors now write of how radiological investigations complement other techniques but are no longer the mainstay. (orig.)

  6. Slow dynamics of the amphibian tympanic membrane

    Science.gov (United States)

    Bergevin, Christopher; Meenderink, Sebastiaan W. F.; van der Heijden, Marcel; Narins, Peter M.

    2015-12-01

    Several studies have demonstrated that delays associated with evoked otoacoustic emissions (OAEs) largely originate from filter delays of resonant elements in the inner ear. However, one vertebrate group is an exception: Anuran (frogs and toads) amphibian OAEs exhibit relatively long delays (several milliseconds), yet relatively broad tuning. These delays, also apparent in auditory nerve fiber (ANF) responses, have been partially attributed to the middle ear (ME), with a total forward delay of ˜0.7 ms (˜30 times longer than in gerbil). However, ME forward delays only partially account for the longer delays of OAEs and ANF responses. We used scanning laser Doppler vibrometery to map surface velocity over the tympanic membrane (TyM) of anesthetized bullfrogs (Rana catesbeiana). Our main finding is a circularly-symmetric wave on the TyM surface, starting at the outer edges of the TyM and propagating inward towards the center (the site of the ossicular attachment). This wave exists for frequencies ˜0.75-3 kHz, overlapping the range of bullfrog hearing (˜0.05-1.7 kHz). Group delays associated with this wave varied from 0.4 to 1.2 ms and correlated with with TyM diameter, which ranged from ˜6-16 mm. These delays correspond well to those from previous ME measurements. Presumably the TyM waves stem from biomechanical constraints of semi-aquatic species with a relatively large tympanum. We investigated some of these constraints by measuring the pressure ratio across the TyM (˜10-30 dB drop, delay of ˜0.35 ms), the effects of ossicular interruption, the changes due to physiological state of TyM (`dry-out'), and by calculating the middle-ear input impedance. In summary, we found a slow, inward-traveling wave on the TyM surface that accounts for a substantial fraction of the relatively long otoacoustic and neurophysiological delays previously observed in the anuran inner ear.

  7. CT assessment of anastomotic bowel leak

    International Nuclear Information System (INIS)

    Aim: To evaluate the predictors of clinically important gastrointestinal anastomotic leaks using multidetector computed tomography (CT). Subjects and methods: Ninety-nine patients, 73 with clinical suspicion of anastomotic bowel leak and 26 non-bowel surgery controls underwent CT to investigate postoperative sepsis. Fifty patients had undergone large bowel and 23 small bowel anastomoses. The time interval from surgery was 3-30 days (mean 10 ± 5.9 SD) for the anastomotic group and 3-40 days (mean 14 ± 11 SD) for the control group (p = 0.3). Two radiologists blinded to the final results reviewed the CT examinations in consensus and recorded the presence of peri-anastomotic air, fluid or combination of the two; distant loculated fluid or combination of fluid and air; free air or fluid; and intestinal contrast leak. Final diagnosis of clinically important anastomotic leak (CIAL) was confirmed at surgery or by chart review of predetermined clinical and laboratory criteria. Results: The prevalence of CIAL in the group undergoing CT was 31.5% (23/73). The CT examinations with documented leak were performed 5-28 (mean; 11.4 ± 6 SD) days after surgery. Nine patients required repeat operation, 10 percutaneous abscess drainage, two percutaneous drainage followed by surgery, and two prolonged antibiotic treatment and total parenteral nutrition (TPN). Of the CT features examined, only peri-anastomotic loculated fluid containing air was more frequently seen in the CIAL group as opposed to the no leak group (p = 0.04). There was no intestinal contrast leakage in this cohort. Free air was present up to 9 days and loculated air up to 26 days without CIAL. Conclusion: Most postoperative CT features overlap between patients with and without CIAL. The only feature seen statistically more frequently with CIAL is peri-anastomotic loculated fluid containing air

  8. Arthritic manifestations of inflammatory bowel disease.

    OpenAIRE

    Suh, C. H.; Lee, C H; Lee, J.; Song, C. H.; Lee, C.W.; Kim, W. H.; S.K. Lee

    1998-01-01

    Inflammatory bowel disease (IBD) is commonly associated with arthritic manifestations. They are divided into three clinical categories; peripheral arthritis, spondylitis, and sacroiliitis. To evaluate the incidence of arthritis associated with IBD in Korea, we retrospectively reviewed one hundred and twenty-nine patients with IBD, 77 with ulcerative colitis (UC) and 52 with Crohn's disease (CD). Arthritis occurred in twenty-two patients (17.1%); 15 with UC(19.6%), 7 with CD (13.5%). Patients ...

  9. Small bowel neoplasm - a diagnostic dilemma

    International Nuclear Information System (INIS)

    Although uncommon, small bowel tumors often present as a diagnostic dilemma for the clinicians. This important clinical entity requires various diagnostic steps and quite often these steps have to be repeated to reach a firm diagnosis. We present here our experience with three such cases and a brief review of the literature regarding the presentation and the diagnostic steps found helpful in arriving at a diagnosis. (author)

  10. Using abdominal massage in bowel management.

    Science.gov (United States)

    Connor, Michelle; Hunt, Catherine; Lindley, Alison; Adams, John

    2014-07-15

    This article describes the introduction of abdominal massage techniques by a community team as part of a total bowel management programme for people with learning disabilities. A trust-wide audit of prescribed laxative use by this client group raised concerns, and led to a more systematic approach to managing constipation in people with learning disabilities. An education programme for carers proved to be successful. Some reported that adopting abdominal massage provided further opportunity to develop the therapeutic relationship. PMID:25005415

  11. Anastomotic disruption after large bowel resection

    OpenAIRE

    NasirKhan, Mohammad U; Abir, Farshad; Longo, Walter; Kozol, Robert

    2006-01-01

    Anastomotic disruption is a feared and serious complication of colon surgery. Decades of research have identified factors favoring successful healing of anastomoses as well as risk factors for anastomotic disruption. However, some factors, such as the role of mechanical bowel preparation, remain controversial. Despite proper caution and excellent surgical technique, some anastomotic leaks are inevitable. The rapid identification of anastomotic leaks and the timely treatment in these cases are...

  12. The evolving epidemiology of inflammatory bowel disease.

    LENUS (Irish Health Repository)

    Shanahan, Fergus

    2009-07-01

    Epidemiologic studies in inflammatory bowel disease (IBD) include assessments of disease burden and evolving patterns of disease presentation. Although it is hoped that sound epidemiologic studies provide aetiological clues, traditional risk factor-based epidemiology has provided limited insights into either Crohn\\'s disease or ulcerative colitis etiopathogenesis. In this update, we will summarize how the changing epidemiology of IBD associated with modernization can be reconciled with current concepts of disease mechanisms and will discuss studies of clinically significant comorbidity in IBD.

  13. Recent advances in small bowel diseases: PartⅡ

    Institute of Scientific and Technical Information of China (English)

    Alan BR Thomson; Angeli Chopra; Michael Tom Clandinin; Hugh Freeman

    2012-01-01

    As is the case in all areas of gastroenterology and hepatology,in 2009 and 2010 there were many advances in our knowledge and understanding of small intestinal diseases.Over 1000 publications were reviewed,and the important advances in basic science as well as clinical applications were considered.In Part Ⅱ we review six topics:absorption,short bowel syndrome,smooth muscle function and intestinal motility,tumors,diagnostic imaging,and cystic fibrosis.

  14. Use of thiopurines in inflammatory bowel disease

    OpenAIRE

    Frei, Pascal; Biedermann, Luc; Nielsen, Ole Haagen; Rogler, Gerhard

    2013-01-01

    The use of thiopurines as immunosuppression for the treatment of refractory or chronic active inflammatory bowel disease is established for both Crohn's disease and ulcerative colitis. Nevertheless, many questions remain concerning the optimal treatment regimens of azathioprine, 6-mercaptopurine and thioguanine. We will briefly summarize dose recommendations, indications for thiopurine therapy and side effects which are relevant in clinical practice. We discuss some currently debated topics, ...

  15. Environmental Risk Factors for Inflammatory Bowel Disease

    OpenAIRE

    Molodecky, Natalie A; Kaplan, Gilaad G

    2010-01-01

    Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract and is associated with significant morbidity. The etiology of IBD has been extensively studied during the last several decades; however, causative factors in disease pathology are not yet fully understood. IBD is thought to result from the interaction between genetic and environmental factors that influence the normal intestinal commensal flora to trigger an inappropriate mucosal immune res...

  16. Environment and the Inflammatory Bowel Diseases

    OpenAIRE

    Frolkis, Alexandra; Dieleman, Levinus A.; Barkema, Herman W.; Panaccione, Remo; Ghosh, Subrata; Richard N Fedorak; Madsen, Karen; Kaplan, Gilaad G; on behalf of the Alberta IBD Consortium

    2013-01-01

    Inflammatory bowel diseases (IBD), which consists of Crohn disease and ulcerative colitis, are chronic inflammatory conditions of the gas-trointestinal tract. In genetically susceptible individuals, the interaction between environmental factors and normal intestinal commensal flora is believed to lead to an inappropriate immune response that results in chronic inflammation. The incidence of IBD have increased in the past century in developed and developing countries. The purpose of the presen...

  17. Environmental Triggers for Inflammatory Bowel Disease

    OpenAIRE

    Ananthakrishnan, Ashwin N

    2013-01-01

    Inflammatory bowel diseases [IBD; Crohn’s disease (CD), ulcerative colitis (UC)] are chronic immunologically mediated diseases that are due to a dysregulated immune response to intestinal flora in a genetically susceptible host. Despite advances in genetics, the likelihood of occurrence of disease remains incompletely explained and there appears to be a strong role for the environment in mediating risk of disease. Smoking remains the most widely studied and replicated risk factor, contributin...

  18. Environment and the inflammatory bowel diseases

    OpenAIRE

    Frolkis, Alexandra; Dieleman, Levinus A.; Barkema, Herman W.; Panaccione, Remo; Ghosh, Subrata; Richard N Fedorak; Madsen, Karen; Kaplan, Gilaad G

    2013-01-01

    Inflammatory bowel diseases (IBD), which consists of Crohn disease and ulcerative colitis, are chronic inflammatory conditions of the gas-trointestinal tract. In genetically susceptible individuals, the interaction between environmental factors and normal intestinal commensal flora is believed to lead to an inappropriate immune response that results in chronic inflammation. The incidence of IBD have increased in the past century in developed and developing countries. The purpose of the presen...

  19. CT assessment of anastomotic bowel leak

    Energy Technology Data Exchange (ETDEWEB)

    Power, N. [Department of Radiology, Sunnybrook Hospital, Toronto, Ontario M4N 3M5 (Canada); Atri, M. [Department of Radiology, Sunnybrook Hospital, Toronto, Ontario M4N 3M5 (Canada)]. E-mail: mostafa.atri@sw.ca; Ryan, S. [Department of Radiology, Sunnybrook Hospital, Toronto, Ontario M4N 3M5 (Canada); Haddad, R. [Department of Surgery, Sunnybrook Hospital, Toronto, Ontario M4N 3M5 (Canada); Smith, A. [Department of Surgery, Sunnybrook Hospital, Toronto, Ontario M4N 3M5 (Canada)

    2007-01-15

    Aim: To evaluate the predictors of clinically important gastrointestinal anastomotic leaks using multidetector computed tomography (CT). Subjects and methods: Ninety-nine patients, 73 with clinical suspicion of anastomotic bowel leak and 26 non-bowel surgery controls underwent CT to investigate postoperative sepsis. Fifty patients had undergone large bowel and 23 small bowel anastomoses. The time interval from surgery was 3-30 days (mean 10 {+-} 5.9 SD) for the anastomotic group and 3-40 days (mean 14 {+-} 11 SD) for the control group (p = 0.3). Two radiologists blinded to the final results reviewed the CT examinations in consensus and recorded the presence of peri-anastomotic air, fluid or combination of the two; distant loculated fluid or combination of fluid and air; free air or fluid; and intestinal contrast leak. Final diagnosis of clinically important anastomotic leak (CIAL) was confirmed at surgery or by chart review of predetermined clinical and laboratory criteria. Results: The prevalence of CIAL in the group undergoing CT was 31.5% (23/73). The CT examinations with documented leak were performed 5-28 (mean; 11.4 {+-} 6 SD) days after surgery. Nine patients required repeat operation, 10 percutaneous abscess drainage, two percutaneous drainage followed by surgery, and two prolonged antibiotic treatment and total parenteral nutrition (TPN). Of the CT features examined, only peri-anastomotic loculated fluid containing air was more frequently seen in the CIAL group as opposed to the no leak group (p = 0.04). There was no intestinal contrast leakage in this cohort. Free air was present up to 9 days and loculated air up to 26 days without CIAL. Conclusion: Most postoperative CT features overlap between patients with and without CIAL. The only feature seen statistically more frequently with CIAL is peri-anastomotic loculated fluid containing air.

  20. Functional findings in irritable bowel syndrome

    OpenAIRE

    Posserud, Iris; Ersryd, Amanda; Simrén, Magnus

    2006-01-01

    The pathophysiology of IBS is complex and still incompletely known. Both central and peripheral factors, including psychosocial factors, abnormal GI motility and secretion, and visceral hypersensitivity, are thought to contribute to the symptoms of IBS. Several studies have demonstrated altered GI motor function in IBS patients and the pattern differs between IBS subgroups based on the predominant bowel pattern. Few studies have so far addressed GI secretion in IBS, but there are some evidenc...

  1. Asian Motility Studies in Irritable Bowel Syndrome

    OpenAIRE

    Lee, Oh Young

    2010-01-01

    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 dysmotili...

  2. Anastomotic disruption after large bowel resection

    Institute of Scientific and Technical Information of China (English)

    Mohammad U NasirKhan; Farshad Abir; Walter Longo; Robert Kozol

    2006-01-01

    Anastomotic disruption is a feared and serious complication of colon surgery. Decades of research have identified factors favoring successful healing of anastomoses as well as risk factors for anastomotic disruption. However, some factors, such as the role of mechanical bowel preparation, remain controversial.Despite proper caution and excellent surgical technique,some anastomotic leaks are inevitable. The rapid identification of anastomotic leaks and the timely treatment in these cases are paramount.

  3. Breath tests and irritable bowel syndrome

    OpenAIRE

    Rana, Satya Vati; Malik, Aastha

    2014-01-01

    Breath tests are non-invasive tests and can detect H2 and CH4 gases which are produced by bacterial fermentation of unabsorbed intestinal carbohydrate and are excreted in the breath. These tests are used in the diagnosis of carbohydrate malabsorption, small intestinal bacterial overgrowth, and for measuring the orocecal transit time. Malabsorption of carbohydrates is a key trigger of irritable bowel syndrome (IBS)-type symptoms such as diarrhea and/or constipation, bloating, excess flatulence...

  4. Irritable bowel syndrome and food interaction

    OpenAIRE

    Cuomo, Rosario; Andreozzi, Paolo; Zito, Francesco Paolo; Passananti, Valentina; De Carlo, Giovanni; Sarnelli, Giovanni

    2014-01-01

    Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders in Western countries. Despite the high prevalence of this disorders, the therapeutic management of these patients is often unsatisfactory. A number of factors have been suggested to be involved in the pathogenesis of IBS, including impaired motility and sensitivity, increased permeability, changes in the gut microbiome and alterations in the brain-gut axis. Also food seems to play a critical role: the most of ...

  5. Modern MRI of the small bowell

    International Nuclear Information System (INIS)

    The radiological diagnostics of diseases of the small intestine have undergone a great change in the last two decades. Through rapid progress with new treatments and an increasing therapeutic focus on transmural healing, a complete evaluation of the gastrointestinal tract is now crucial. With the introduction of endoscopy, gastrointestinal imaging with a relatively high radiation exposure had only limited applications. The development of cross-sectional imaging allowed a much broader radiological evaluation of abdominal diseases. Due to rapid investigation techniques, excellent soft tissue contrast and the distinct advantage of eliminating exposure to radiation, magnetic resonance imaging (MRI) of the gastrointestinal tract has gained increasing importance. With sufficient filling of the intestinal lumen, simultaneous imaging of all the intestinal wall layers, the perienteric structures and associated abdominal pathologies is now possible. New MR sequences, such as diffusion-weighted sequences, dynamic contrast-enhanced sequences and MR fluoroscopy, enable the detection of morphological changes, with additional characterization of affected bowel loops as well as the assessment of functional pathologies with dynamic information about intestinal motility disturbances. Recent guidelines of European radiological and gastroenterological organizations have confirmed the importance of cross-sectional imaging and particularly of MRI for diagnostics and follow-up in patients with Crohn's disease. Due to the possibility of assessment of all the layers of the intestinal wall and the presence of extramural complications, MRI has a significant impact on further therapeutic treatment in patients with inflammatory bowel disease. Especially in patients with inflammatory bowel disease, MR enterography and MR enteroclysis should be the methods of choice for the evaluation of small bowel pathologies because of radiation issues and the great diagnostic value they provide. A

  6. Biologic Concentration Testing in Inflammatory Bowel Disease

    OpenAIRE

    Vaughn, Byron P; Sandborn, William J; Cheifetz, Adam S.

    2015-01-01

    Abstract: Anti-TNF medications have revolutionized the care of patients with inflammatory bowel disease. However, despite an initial robust effect, loss of response is common and long-term results are disappointing. Much of this lack of durability may be due to inadequate dose optimization, and recent studies suggest a correlation between serum drug concentrations and clinical outcomes. Currently, in clinical practice, measurement of drug concentrations and antibodies to drug are typically pe...

  7. Minimally Invasive Surgery for Inflammatory Bowel Disease

    OpenAIRE

    Holder-Murray, Jennifer; Marsicovetere, Priscilla; Holubar, Stefan D

    2015-01-01

    Abstract: Surgical management of inflammatory bowel disease is a challenging endeavor given infectious and inflammatory complications, such as fistula, and abscess, complex often postoperative anatomy, including adhesive disease from previous open operations. Patients with Crohn's disease and ulcerative colitis also bring to the table the burden of their chronic illness with anemia, malnutrition, and immunosuppression, all common and contributing independently as risk factors for increased su...

  8. An atypical case of large bowel obstruction

    OpenAIRE

    Hughes, Kaylie E.; Arthur, James

    2013-01-01

    In Europe up to nine per cent of people suffer from renal calculi during their lifetime. Staghorn calculi are common and account for ∼11% of cases. Classic presentations include persistent loin pain, recurrent pyelonephritis or cystitis-like symptoms, renal colic or occasional haematuria. We present what we believe to be the first documented case of large bowel obstruction caused by a benign colonic stricture formed secondary to extravasation of a staghorn calculus.

  9. Immunogenetic Susceptibilities in Inflammatory Bowel Disease

    OpenAIRE

    Rotter, Jerome I

    1990-01-01

    It is now clear that the major identified risk factor for the inflammatory bowel diseases (IBDs) is a positive family history. Furthermore, the available data in spouses and twins indicate that the genetic susceptibility is due in large measure to shared familial predisposition. This emphasizes the importance of identifying the actual familial susceptibilities. Given the data for immunopathogenetic etiologies in the genesis of IBD, the logical candidate genes are those that involve the immune...

  10. Intestinal epithelial cells in inflammatory bowel diseases

    Institute of Scientific and Technical Information of China (English)

    Giulia; Roda; Alessandro; Sartini; Elisabetta; Zambon; Andrea; Calafiore; Margherita; Marocchi; Alessandra; Caponi; Andrea; Belluzzi; Enrico; Roda

    2010-01-01

    The pathogenesis of inflammatory bowel diseases (IBDs) seems to involve a primary defect in one or more of the elements responsible for the maintenance of intestinal homeostasis and oral tolerance. The most important element is represented by the intestinal barrier, a complex system formed mostly by intestinal epithelial cells (IECs). IECs have an active role in producing mucus and regulating its composition; they provide a physical barrier capable of controlling antigen traff ic through the intestinal muco...

  11. Sellar inflammatory mass with inflammatory bowel disease

    OpenAIRE

    Freeman, Hugh J; Maguire, John

    2010-01-01

    Inflammatory bowel disease may be associated with different intracranial disorders. An inflammatory sellar mass is very rare but includes a variety of noninfectious causes including lymphocytic hypophysitis, granulomatous inflammation and Wegener’s granulomatosis. A 32-year-old man was diagnosed with an inflammatory sellar mass associated with an extensive colonic inflammatory process clinically characteristic of Crohn’s disease. The concurrent onset of these inflammatory disorders in distinc...

  12. Case report: Congenital short bowel syndrome

    OpenAIRE

    Palle Lalitha; Reddy Balaji

    2010-01-01

    Congenital short bowel syndrome (SBS) is a relatively rare condition as compared to acquired SBS. It is associated with significant mortality and morbidity. Infants usually present with failure to thrive, recurrent vomiting, and diarrhea. It is important to suspect and diagnose this condition promptly, as early initiation of parenteral nutrition or surgery, if necessary, may result in a favorable outcome. We discuss a case of an infant aged 26 days, who presented with failure to thrive, recur...

  13. Irritable bowel syndrome and its psychological management

    Directory of Open Access Journals (Sweden)

    Ravikesh Tripathi

    2015-01-01

    Full Text Available Irritable Bowel Syndrome (IBS is a chronic and disabling gastrointestinal problem that affects psychosocial functioning as well as the quality of life. This case study reports the utility of cognitive behavior therapy as a psychological intervention procedure in a chronic case of IBS. The use of psychological intervention was found to result in a reduction of anxiety; amelioration of the symptoms associated with IBS and improved functioning.

  14. Persistent omphalomesenteric duct causing small bowel obstruction in an adult

    Institute of Scientific and Technical Information of China (English)

    Haridimos Markogiannakis; Dimitrios Theodorou; Konstantinos G Toutouzas; Panagiotis Drimousis; Sotirios Georgios Panoussopoulos; Stilianos Katsaragakis

    2007-01-01

    An extremely rare case of persistent omphalomesenteric duct causing small bowel obstruction is presented. A 20-year-old female patient without medical history presented with colicky abdominal pain, vomiting, absence of passage of gas and feces, and abdominal distension of 24 h duration. Physical examination and blood tests were normal. Abdominal X-ray showed small bowel obstruction.Computed tomography of the abdomen demonstrated dilated small bowel and a band originating from the umbilicus and continuing between the small bowel loops;an omphalomesenteric duct remnant was suspected. In exploratory laparotomy, persistent omphalomesenteric duct causing small bowel obstruction was identified and resected. The patient had an uneventful recovery and was discharged on the 5th postoperative day. Although persistent omphalomesenteric duct is an extremely infrequent cause of small bowel obstruction in adult patients, it should be taken into consideration in patients without any previous surgical history.

  15. The epidemiology of irritable bowel syndrome

    Directory of Open Access Journals (Sweden)

    Canavan C

    2014-02-01

    Full Text Available Caroline Canavan, Joe West, Timothy Card Division of Epidemiology and Public Health, University of Nottingham, Nottingham, UK Abstract: Irritable bowel syndrome (IBS is a functional condition of the bowel that is diagnosed using clinical criteria. This paper discusses the nature of the diagnostic process for IBS and how this impacts epidemiological measurements. Depending on the diagnostic criteria employed, IBS affects around 11% of the population globally. Around 30% of people who experience the symptoms of IBS will consult physicians for their IBS symptoms. These people do not have significantly different abdominal symptoms to those who do not consult, but they do have greater levels of anxiety and lower quality of life. Internationally, there is a female predominance in the prevalence of IBS. There is 25% less IBS diagnosed in those over 50 years and there is no association with socioeconomic status. IBS aggregates within families and the genetic and sociological factors potentially underlying this are reviewed. Patients diagnosed with IBS are highly likely to have other functional disease and have more surgery than the general population. There is no evidence that IBS is associated with an increased mortality risk. The epidemiological evidence surrounding these aspects of the natural history is discussed. Keywords: irritable bowel syndrome, epidemiology, prevalence, mortality, natural history

  16. Osteoporosis in patients with inflammatory bowel disease

    International Nuclear Information System (INIS)

    The prevalence of osteoporosis in inflammatory bowel disease (IBD) has not been accurately established. Using single photon absorptiometry (SPA) and vertebral quantitative computerized tomography (QCT) the authors measured bone mineral content (BMC) in 75 unselected patients with IBD. Osteoporosis was present in 23 (31%). Seven had cortical and trabecular osteoporosis, 11 cortical only and five trabecular only. Three amenorrhoeic premenopausal females had clinically severe osteoporosis and a further 4 had vertebral crush fractures. The median lifetime steroid dose in osteoporotic patients was significantly greater than in patients with normal BMC; most patients with osteoporosis had small bowel IBD with one or more resections. Repeat QCT measurements in 18 patients after one year were unchanged in 12, increased in one and decreased between 10 and 37 mg/ml K2HPO4 in 5 of whom four were receiving steroids. Radial BMC decreased in one patient, increased in one and was unchanged in the remainder. Thus, osteoporosis was present in 30% of these patients, with severe clinical disease in three young females. Rapid spinal trabecular bone loss was demonstrated over the course of one year in some patients. Steroid therapy, amenorrhoe and small bowel IBD with resection appear to be important risk factors

  17. [Irritable bowel syndrome: a functional disorder?].

    Science.gov (United States)

    Man, Fernando; Bustos Fernández, Luis María

    2013-12-01

    Irritable bowel syndrome is a highly prevalent condition responsible for almost one third of visits to the gastroenterologist and huge expenses for diagnosis, treatment and loss of working days. A unique pathophysiologic mechanism has not been elucidated yet and several possibilities have been proposed such as senso-perception and motor disturbances, the effect of stress and anxiety, serotonin receptor failures, activation of abnormal brain areas and pain modulation differences, among others. The absence of a biological marker has led the investigators to consider this syndrome as an exclusion diagnostic condition, once the organic diseases have been discarded The changes in gut microbiota have recently raised great interest among gastroenterologists. The study of the small intestinal bowel overgrowth syndrome, the effect of antibiotics upon the flora, the recognition of post-infectious irritable bowel syndrome and the action of probiotics, together with the effect of malabsortion of diet carbohydrates have brought some new light in our knowledge. The present update will focus on the published evidence about the subject, bearing in mind that the mechanisms elicited here are only suitable for a subgroup of patients. PMID:24516961

  18. Occult spondyloarthritis in inflammatory bowel disease.

    Science.gov (United States)

    Bandinelli, Francesca; Manetti, Mirko; Ibba-Manneschi, Lidia

    2016-02-01

    Spondyloarthritis (SpA) is a frequent extra-intestinal manifestation in patients with inflammatory bowel disease (IBD), although its real diffusion is commonly considered underestimated. Abnormalities in the microbioma and genetic predisposition have been implicated in the link between bowel and joint inflammation. Otherwise, up to date, pathogenetic mechanisms are still largely unknown and the exact influence of the bowel activity on rheumatic manifestations is not clearly explained. Due to evidence-based results of clinical studies, the interest on clinically asymptomatic SpA in IBD patients increased in the last few years. Actually, occult enthesitis and sacroiliitis are discovered in high percentages of IBD patients by different imaging techniques, mainly enthesis ultrasound (US) and sacroiliac joint X-ray examinations. Several diagnostic approaches and biomarkers have been proposed in an attempt to correctly classify and diagnose clinically occult joint manifestations and to define clusters of risk for patient screening, although definitive results are still lacking. The correct recognition of occult SpA in IBD requires an integrated multidisciplinary approach in order to identify common diagnostic and therapeutic strategies. The use of inexpensive and rapid imaging techniques, such as US and X-ray, should be routinely included in daily clinical practice and trials to correctly evaluate occult SpA, thus preventing future disability and worsening of quality of life in IBD patients. PMID:26354428

  19. Can Probiotics Cure Inflammatory Bowel Diseases?

    Science.gov (United States)

    Korada, Siva Kumar; Yarla, Nagendra Sastry; Bishayee, Anupam; Aliev, Gjumrakch; Aruna Lakshmi, K; Arunasree, M K; Dananajaya, B L; Mishra, Vijendra

    2016-01-01

    Gastrointestinal (GI) disorders, especially microbial dysbiosis play role in several GI ailments such as irritable bowel syndrome, colorectal cancer, inflammatory bowel diseases, and antibiotic-associated diarrhoea. Role of inflammatory bowel disease (IBD) is multifactorial as it involves loss of maintaining intestinal epithelial barrier integrity, increased release of pro-inflammatory molecules, and microbial dysbiosis in gut microflora. Some specific pathogens also play a key role in the IBD development. The origin and causation are still in unfathomable condition and the exact root cause is unknown. Recently probiotic studies have been gaining importance because of their positive responses in their IBD experimental results. According to joint Food and Agricultural Organisation/World Health Organisation working group, probiotics are defined as live microorganisms which when administered in adequate amount confer health benefit on the host. These live beneficial microorganisms are considered helpful in improving gut colonization and perseverance thereby improves prophylactic effect. In the direction of IBD research, a number of studies are needed to standardize its methodology and its applicability on human usage. The particular review presents an overview of gut microflora and its impact on host health, types of IBD and existing therapies to treat this disorder, mechanism of several probiotic actions, role of probiotics in IBD prevention with their supporting evidences. PMID:26648465

  20. Towards Predicting the Added Resistance of Slow Ships in Waves

    DEFF Research Database (Denmark)

    Amini Afshar, Mostafa

    -surface boundary conditions. The field continuity equation has been discretised by a centered fourth-order finite difference scheme which also includes ghost layers at the boundaries. For the zero-speed hydrodynamic problem, the same centered scheme can be utilised to calculate the free-surface derivatives...... validated against analytical solutions for simple exact geometries like a cylinder and a sphere. The solver is now ready to be exercised on real ship geometries....

  1. Towards Predicting the Added Resistance of Slow Ships in Waves

    OpenAIRE

    Amini Afshar, Mostafa; Bingham, Harry B.; Andersen, Poul

    2014-01-01

    I dag sejler skibe relativt langsomt, fordi det giver bedre effektivitet i form af mindre brændstofforbrug og reduceret udslip af forurening. At sejle langsomt er også den nemmeste vej mod at opfylde de kommende krav til udslip af drivhusgasser fra den maritime industri. Det giver et incitament til at designe nye skibe til lav fart og dermed med mindre motorer. Men optimeringen af skibets effektivitet må ikke gå ud over sikkerheden. For eksempel skal et skib altid have fornøden motorkraft til...

  2. Rifaximin in irritable bowel syndrome: rationale, evidence and clinical use

    OpenAIRE

    Saadi, Mohammed; McCallum, Richard W.

    2013-01-01

    Irritable bowel syndrome (IBS) is the most common functional bowel disease that affects up to 15% of the US population. The majority of patients with IBS have significant bloating and gas. Recent evidence is beginning to suggest that patients with IBS may have an alteration in the gastrointestinal flora. Specifically, findings suggest that patients with IBS have excessive bacteria in the small bowel, referred to as bacterial overgrowth. Therefore there may be benefits of antibiotic-based ther...

  3. Pathophysiology of acute small bowel disease with CT correlation

    International Nuclear Information System (INIS)

    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.

  4. 18B. Integrative Solutions for the Irritable Bowel Syndrome

    OpenAIRE

    Mullin, Gerard; Lee, Linda

    2013-01-01

    Focus Areas: Integrative Approaches to Care, Pediatrics The irritable bowel syndrome (IBS) is a functional bowel disorder characterized by abdominal pain and altered bowel movements. The diagnosis of IBS is established by the Rome III criteria. IBS afflicts 10% to 15% of the US population (30 million Americans) and is the most common digestive disorder seen in the primary care setting. Patients with IBS have an impaired quality of life and high rate of absenteeism from work with diminished pr...

  5. Intestinal microbiota in pathophysiology and management of irritable bowel syndrome

    OpenAIRE

    Lee, Kang Nyeong; Lee, Oh Young

    2014-01-01

    Irritable bowel syndrome (IBS) is a functional bowel disorder without any structural or metabolic abnormalities that sufficiently explain the symptoms, which include abdominal pain and discomfort, and bowel habit changes such as diarrhea and constipation. Its pathogenesis is multifactorial: visceral hypersensitivity, dysmotility, psychosocial factors, genetic or environmental factors, dysregulation of the brain-gut axis, and altered intestinal microbiota have all been proposed as possible cau...

  6. Dysmotility of the small intestine in irritable bowel syndrome.

    OpenAIRE

    Kellow, J E; Phillips, S F; Miller, L J; Zinsmeister, A R

    1988-01-01

    Though the pathophysiology of the irritable bowel syndrome (IBS) is commonly attributed to dysfunction of the large intestine, evidence exists to incriminate the small bowel. In order to further explore the role of the small bowel in IBS several stimuli were applied, in an attempt to unmask the dysmotility of the jejunum and ileum. These included infusions of cholecystokinin-octapeptide (CCK-OP), a high fat meal, neostigmine and balloon distension of the ileum. Three groups (n = 8) each of ag...

  7. Pathophysiology of acute small bowel disease with CT correlation

    Energy Technology Data Exchange (ETDEWEB)

    Sarwani, N., E-mail: nsarwani@hmc.psu.ed [Department of Radiology, Section of Abdominal Imaging, Penn State Milton Hershey Medical Center, Hershey, PA (United States); Tappouni, R.; Tice, J. [Department of Radiology, Section of Abdominal Imaging, Penn State Milton Hershey Medical Center, Hershey, PA (United States)

    2011-01-15

    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.

  8. The Usefulness of Capsule Endoscopy for Small Bowel Tumors

    OpenAIRE

    Cheung, Dae Young; Kim, Jin Su; Shim, Ki-Nam; Choi, Myung-Gyu; ,

    2016-01-01

    Video capsule endoscopy (VCE) has expanded the range of endoscopic examination of the small bowel. The clinical application of VCE is mainly for obscure gastrointestinal bleeding (OGIB) and small bowel tumor is one of the clinically significant diagnoses of VCE, often requiring subsequent invasive interventions. Small bowel tumors are detected with a frequency of around 4% with VCE in indications of OGIB, iron deficiency anemia, unexplained abdominal pain, and others. Protruding mass with ble...

  9. The diagnostic role of MDCT enterography in small bowel lesions

    OpenAIRE

    Hasan I. Megally; Hosam eldin Mohamed Elmalah; Gehan S. Seifeldein; Nisreen Adel Abbas; Hussien Ahmed Elamin

    2015-01-01

    Purpose: To evaluate the role of MDCT enterography in the diagnosis of small bowel diseases. Patient and methods: Thirty nine patients suspected to have small bowel diseases were examined with 64 MDCT enterography. Result: MDCT enterography easily diagnosed small intestinal diseases which confirmed with histopathological results, operative data and follow up. Conclusions: MDCT can be used as a front-line imaging and one stop imaging modality for the detection of small bowel diseases....

  10. Effect of cholecystectomy on bowel function: a prospective, controlled study

    OpenAIRE

    Hearing, S; Thomas, L.; HEATON, K; Hunt, L.

    1999-01-01

    BACKGROUND—Published estimates of the prevalence of postcholecystectomy diarrhoea derive from retrospective or uncontrolled data. They ignore functional bowel syndromes and possible changes in diet and drug use.
AIMS—To determine prospectively whether and how often cholecystectomy leads to changes in bowel function and bowel symptoms, especially to liquid stools, over and above any non-specific effect of laparoscopic surgery.
SUBJECTS—Patients: 106 adults undergoing laparoscopic cholecystecto...

  11. 5-Millimeter Trocar-Site Bowel Herniation Following Laparoscopic Surgery

    OpenAIRE

    Khurshid, Nauman; Chung, Maurice; Horrigan, Terrence; Manahan, Kelly; Geisler, John P.

    2012-01-01

    Background and Objectives: This is a case report of a 5-mm trocar-site large bowel herniation following laparoscopic tubal sterilization. During laparoscopic sterilization, the 5-mm port site was closed initially. Large bowel herniation was recognized at the end of the case and managed immediately by laparoscopically reducing the hernia and closing the port site without any short- or long-term complications. Trocar-site bowel hernia is a rare complication after laparoscopic surgery. It is usu...

  12. Small bowel obstruction secondary to a liberated Meckel's enterolith

    OpenAIRE

    Demetriou, Vias; McKean, David; Briggs, James; Moore, Niall

    2013-01-01

    A 30-year-old woman presented with a short history of abdominal pain which rapidly progressed to absolute constipation. An abdominal radiograph demonstrated a paucity of bowel gas and a 4 cm lesion with concentric laminar calcification projected over the pelvis. A CT scan revealed a 4 cm giant Meckel's diverticulum, downstream of which a laminated mass was impacted in the lumen of the distal ileum causing small bowel obstruction. Subsequent surgery confirmed small bowel obstruction secondary ...

  13. Intussusception of the bowel in adults: A review

    OpenAIRE

    Marinis, Athanasios; Yiallourou, Anneza; Samanides, Lazaros; Dafnios, Nikolaos; Anastasopoulos, Georgios; Vassiliou, Ioannis; Theodosopoulos, Theodosios

    2009-01-01

    Intussusception of the bowel is defined as the telescoping of a proximal segment of the gastrointestinal tract within the lumen of the adjacent segment. This condition is frequent in children and presents with the classic triad of cramping abdominal pain, bloody diarrhea and a palpable tender mass. However, bowel intussusception in adults is considered a rare condition, accounting for 5% of all cases of intussusceptions and almost 1%-5% of bowel obstruction. Eight to twenty percent of cases a...

  14. Incoherent "Slow and Fast Light"

    CERN Document Server

    Zapasskii, V S

    2009-01-01

    We show experimentally that the effects of "slow and fast light" that are considered to be caused by spectral hole-burning under conditions of coherent population oscillations (CPO) can be universally observed with incoherent light fields on objects with the pure-intensity nonlinearity, when such an interpretation is inapplicable. As a light source, we used an incandescent lamp and as objects for study, a photochromic glass and a thermochromic coating. The response of the objects to intensity modulation of the incident light reproduced in all details the commonly accepted experimental evidences of the "light with a negative group velocity" and "ultraslow light". We come to conclusion that so far there are no experimental works providing evidence for real observation of the "CPO-based slow or fast light".

  15. Pathophysiology of the nodular and micronodular small bowel fold

    International Nuclear Information System (INIS)

    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

  16. Multislice CT enteroclysis in the diagnosis of bowel endometriosis

    International Nuclear Information System (INIS)

    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.)

  17. 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.)

  18. 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.

  19. CT findings of small bowel rupture after abdominal trauma

    International Nuclear Information System (INIS)

    The accuracy of CT in the detection of injuries of the solid visceral organ is well established, but the value of CT in diagnosing small bowel rupture after abdominal trauma is controversal. This study was conducted to ascertain CT finding of small bowel rupture result from abdominal trauma. A retrospective analysis of preoperative abdominal CT findings in 40 patients was performed. Small bowel rupture was confirmed by surgery. Precontrast and postcontrast enhanced CT images were obtained in all patients. Diagnostic findings of small bowel rupture including pneumoperitoneum or retroperitoneal air, discontinuity of the bowel wall and extravasation of oral contrast materials were observed in 33 cases(83%). Intraperitoneal or retroperitoneal free air was seen in 31 cases(78%) and intraperitoneal or retroperitoneal free fluid collection was seen in 38 patients(95%). Small bowel wall was thickened in 31 cases(78%), bowel wall was enhanced in 12 cases(30%) and bowel wall discontinuity and extravasation of oral contrast material was seen in 5 cases, respectively. The CT scan is sensitive and effective modality for evaluation of small bowel rupture after abdominal trauma, because of high detectability of diagnostic and suggestive CT findings

  20. The pathophysiology of the nodular and micronodular small bowel fold

    International Nuclear Information System (INIS)

    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

  1. Incoherent "Slow and Fast Light"

    OpenAIRE

    Zapasskii, V. S.; Kozlov, G. G.

    2009-01-01

    We show experimentally that the effects of "slow and fast light" that are considered to be caused by spectral hole-burning under conditions of coherent population oscillations (CPO) can be universally observed with incoherent light fields on objects with the pure-intensity nonlinearity, when such an interpretation is inapplicable. As a light source, we used an incandescent lamp and as objects for study, a photochromic glass and a thermochromic coating. The response of the objects to intensity...

  2. Interface waves propagating along tensile fractures in dolomite

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Young Hwan; Hwang, Dae Hyun; Min, Seon Jeong [Dept. of Radiology, Hallym University Dongtan Sacred Heart Hospital, Hwaseong (Korea, Republic of); Woo, Ji Young; Kim, Jeong Won; Hong, Hye Sook; Yang, Ik; Lee, Yul [Hallym University Kangnam Sacred Heart Hospital, Seoul (Korea, Republic of)

    2013-10-15

    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.

  5. Inflammatory bowel disease—the role of cross-sectional imaging techniques in the investigation of the small bowel

    OpenAIRE

    Athanasakos, Athanasios; Mazioti, Argyro; Economopoulos, Nikolaos; Kontopoulou, Christina; Stathis, Georgios; Filippiadis, Dimitrios; Spyridopoulos, Themistoklis; Alexopoulou, Efthymia

    2014-01-01

    Abstract Background: The diagnosis of inflammatory bowel disease (IBD) in children and adolescents is based on the integration of clinical, biological, endoscopic, histological and radiological data. Methods: The most important part of the diagnosis is the histology, which is acquired by endoscopy. Imaging of the small bowel has changed in recent years, but the imaging goals are primarily to determine the extent of small bowel involvement, assess complications and define candidates for surger...

  6. PREVALENCE AND FACTORS AFFECTING REM AND SLOW WAVE SLEEP REBOUND ON CPAP TITRATION STUDY IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA Prevalencia de los factores que afectan el sueño REM y el brote de ondas lentas en los estudios con CPAP en apnea obstructiva del sueño

    Directory of Open Access Journals (Sweden)

    Edgar Osuna S

    2008-03-01

    Full Text Available Background. In patients with obstructive sleep apnea syndrome (OSAS treatment with CPAP results in an increase of REM sleep and slow wave sleep, but there is limited information about the prevalence of REM rebound in patients with OSAS and possible factors related to the rebound. Objective. REM rebound (RR and slow wave sleep rebound (SWSR has been described as a frequent phenomenon that occurs during CPAP titration, but the quantity that qualify for RR has not been mentioned in literature. The objective of our study was to determine the prevalence of REM rebound and slow wave sleep rebound in our sleep disorders center, to attempt to define RR and look for factors that may affect RR and SWSR on the first night of CPAP titration. Materials and methods. We included patients who had both baseline polysomnogram (bPSG and CPAP polysomnogram (cPSG studies done in the same laboratory. We included 179 patients>18 years with Apnea hypopnea index (AHI>10/hr on the baseline study, with an adequate CPAP titration study. We compared the percentages of REM sleep and slow wave sleep during bPSG and cPSG. We analyzed the frequency of presentation and looked for the factors affecting RR and SWSR. Results. 179 patients were enrolled (M/F:118/61, with a mean age of 48.6±4 for men, and 51.6±12.9 for women. The mean interval between the bPSG and cPSG was 45 days. The mean REM percentage during the bPSG was 15.55 percent and during cPSG study it was 21.57 percent. We took 6 percent as our differential point as the results became statistically significant at this point (p:0001. We therefore present our data by dividing our patients population with RR6%. The mean SWS percentage during the bPSG was 8.11±9.68 and during the cPSG was 13.17±10, with a p:0.35 which is not statistically significant. The multiple regression model showed that the variables that contribute more to the REM change are: REM sleep during bPSG (-0.56, bAHI (0.24 and the body mass index (0

  7. Ileo-ileal Intussusception and Bowel Obstruction Caused by Plasmablastic Lymphoma of Small Bowel- A Rare Entity in Rare Location

    Science.gov (United States)

    Thakur, Sanjiv S.

    2016-01-01

    Intussusception of small bowel is considered a rare cause of bowel obstruction in adults accounting for only about 1% of bowel obstruction in adults. Intussusception in adults is uncommon with 95% cases of intussusceptions occurring in children. Adult intussusception from small intestinal lymphoma is also rare with only 36 cases reported in the literature between 2000 and 2011. Plasmablastic lymphoma (PBL) is an aggressive lymphoid neoplasm usually seen in the oral cavity in the clinical setting of human immunodeficiency virus (HIV) infection. Plasmablastic lymphoma of the small intestine is extremely rare. Here, we report a case of plasmablastic lymphoma of small bowel with ileoileal intussusception in an HIV-negative immunocompetent male patient.

  8. Traveling-Wave Tubes

    Science.gov (United States)

    Kory, Carol L.

    1998-01-01

    The traveling-wave tube (TWT) is a vacuum device invented in the early 1940's used for amplification at microwave frequencies. Amplification is attained by surrendering kinetic energy from an electron beam to a radio frequency (RF) electromagnetic wave. The demand for vacuum devices has been decreased largely by the advent of solid-state devices. However, although solid state devices have replaced vacuum devices in many areas, there are still many applications such as radar, electronic countermeasures and satellite communications, that require operating characteristics such as high power (Watts to Megawatts), high frequency (below 1 GHz to over 100 GHz) and large bandwidth that only vacuum devices can provide. Vacuum devices are also deemed irreplaceable in the music industry where musicians treasure their tube-based amplifiers claiming that the solid-state and digital counterparts could never provide the same "warmth" (3). The term traveling-wave tube includes both fast-wave and slow-wave devices. This article will concentrate on slow-wave devices as the vast majority of TWTs in operation fall into this category.

  9. No difference in small bowel microbiota between patients with irritable bowel syndrome and healthy controls.

    Science.gov (United States)

    Dlugosz, Aldona; Winckler, Björn; Lundin, Elin; Zakikhany, Katherina; Sandström, Gunnar; Ye, Weimin; Engstrand, Lars; Lindberg, Greger

    2015-01-01

    Several studies have indicated that colonic microbiota may exhibit important differences between patients with irritable bowel syndrome (IBS) and healthy controls. Less is known about the microbiota of the small bowel. We used massive parallel sequencing to explore the composition of small bowel mucosa-associated microbiota in patients with IBS and healthy controls. We analysed capsule biopsies from the jejunum of 35 patients (26 females) with IBS aged 18-(36)-57 years and 16 healthy volunteers (11 females) aged 20-(32)-48 years. Sequences were analysed based on taxonomic classification. The phyla with the highest total abundance across all samples were: Firmicutes (43%), Proteobacteria (23%), Bacteroidetes (15%), Actinobacteria (9.3%) and Fusobacteria (7.0%). The most abundant genera were: Streptococcus (19%), Veillonella (13%), Prevotella (12%), Rothia (6.4%), Haemophilus (5.7%), Actinobacillus (5.5%), Escherichia (4.6%) and Fusobacterium (4.3%). We found no difference among major phyla or genera between patients with IBS and controls. We identified a cluster of samples in the small bowel microbiota dominated by Prevotella, which may represent a common enterotype of the upper small intestine. The remaining samples formed a gradient, dominated by Streptococcus at one end and Escherichia at the other. PMID:25687743

  10. Slow electrons kill the ozone

    International Nuclear Information System (INIS)

    A new method and apparatus (Trochoidal electron monochromator) to study the interactions of electrons with atoms, molecules and clusters was developed. Two applications are briefly reported: a) the ozone destruction in the atmosphere is caused by different reasons, a new mechanism is proposed, that slow thermal electrons are self added to the ozone molecule (O3) with a high frequency, then O3 is destroyed ( O3 + e- → O- + O2); b) another application is the study of the binding energy of the football molecule C60. (nevyjel)

  11. The heart in inflammatory bowel disease

    Directory of Open Access Journals (Sweden)

    Tsianos E.V.

    2007-03-01

    Full Text Available SUMMARY Cardiovascular involvement in inflammatory bowel disease (IBD has been occasionally reported, mainly in the form of case reports. Endocardium derangement in IBD involves endocarditis and subendocardial abscess. Endocarditis may occur as a result of septicemia or due to the prolonged use of total parental nutrition (TPN catheters or/and immunosuppression. The cause of endocarditis may be bacterial or fungal and require surgery in several cases. Prophylaxis for endocarditis in selected IBD patients is discussed. Myocarditis or perimyocarditis in IBD is reported as an autoimmune phenomenon during bowel disease excacerbations or as a side-effect of 5-aminosalicylic acid (5-ASA formulations. Ulcerative colitis (UC patients seem to be at a higher risk for this complication compared to Crohn�s disease (CD patients. Myocardial infarctions, selenium deficiency during TPN, the role of prolonged steroid use and the association with giant cell myocarditis are topics which need further analysis. Pericardium involvement seems to be the most frequent type of cardiovascular complication in IBD caused by drugs (5-ASA, azathioprine, cyclosporine, pericardio-colonic fistulas or unknown causes (idiopathic and it may occasionally be the disease presenting symptom. Coronary artery status and other factors for cardiovascular risk, such as smoking, hyperlipidemia and exercise are also discussed. Electrocardiogram and ultrasonographic changes are not so uncommon and cardiogenic sudden death in IBD is reviewed. Intracavitary coagulation abnormalities, amyloidosis, heart failure and aortitis syndrome are topics included and discussed in this review. A list of tables contributes to a more systemic overview of this current knowledge. Key Words: heart, inflammatory bowel disease, ulcerative colitis, Crohn�s diseas

  12. What I Need to Know about Bowel Control

    Science.gov (United States)

    ... Organizations​​ (PDF, 341 KB)​​​​​ Alternate Language URL Español What I Need to Know about Bowel Control Page ... about anal discomfort? Points to Remember Clinical Trials What is a bowel control problem? You have a ...

  13. Blunt abdominal trauma with transanal small bowel evisceration

    Directory of Open Access Journals (Sweden)

    Noushif Medappil

    2013-01-01

    Full Text Available Small bowel evisceration through the anus can occur spontaneously or post traumatically. Traumatic transanal small bowel evisceration results from iatrogenic injuries, suction injuries, and blunt abdominal trauma (BAT. We report a 48-year-old female who presented with evisceration of small intestinal loops through the anus following BAT and discuss the etiologies and mechanisms of injury of this rare presentation.

  14. Visceral hypersensitivity in Irritable Bowel Syndrome:pathophysiological mechanisms

    OpenAIRE

    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 composition, intestinal mucosal barrier, serine protease and serotonergic signalling components which may play a role in the visceral hypersensitivity. We showed alterations in microbiota composition...

  15. Small bowel angiodysplasia and novel disease associations: a cohort study.

    LENUS (Irish Health Repository)

    Holleran, Grainne

    2013-04-01

    Gastrointestinal angiodysplasias recurrently bleed, accounting for 3-5% of obscure gastrointestinal bleeding. The advent of small bowel capsule endoscopy (SBCE) has led to an increased recognition of small bowel angiodysplasias (SBAs) but little is known about their etiology. Previous small cohorts and case reports suggest an equal gender incidence and associations with cardiovascular disease, renal impairment, and coagulopathies.

  16. The Usefulness of Capsule Endoscopy for Small Bowel Tumors.

    Science.gov (United States)

    Cheung, Dae Young; Kim, Jin Su; Shim, Ki-Nam; Choi, Myung-Gyu

    2016-01-01

    Video capsule endoscopy (VCE) has expanded the range of endoscopic examination of the small bowel. The clinical application of VCE is mainly for obscure gastrointestinal bleeding (OGIB) and small bowel tumor is one of the clinically significant diagnoses of VCE, often requiring subsequent invasive interventions. Small bowel tumors are detected with a frequency of around 4% with VCE in indications of OGIB, iron deficiency anemia, unexplained abdominal pain, and others. Protruding mass with bleeding, mucosal disruption, irregular surface, discolored area, and white villi are suggested as the VCE findings of small bowel tumor. Device assisted enteroscopy (DAE), computed tomography enteroclysis/enterography and magnetic resonance enteroclysis/enterography also have clinical value in small bowel examination and tumor detection, and they can be used with VCE, sequentially or complementarily. Familial adenomatous polyposis, Peutz-Jeghers syndrome, melanoma, lymphoma, and neuroendocrine tumor with hepatic metastasis are the high risk groups for small bowel tumors, and surveillance programs for small bowel tumors are needed. VCE and radiological imaging have value in screening, and in selected cases, DAE can provide more accurate diagnosis and endoscopic treatment. This review describes the usefulness and clinical impact of VCE on small bowel tumors. PMID:26855919

  17. Potential viral pathogenic mechanism for new variant inflammatory bowel disease

    OpenAIRE

    Uhlmann, V; Martin, C. M.; Sheils, O; Pilkington, L; I. Silva; Killalea, A; Murch, S B; Walker-Smith, J; Thomson, M.; Wakefield, A J; O'Leary, J J

    2002-01-01

    Aims: A new form of inflammatory bowel disease (ileocolonic lymphonodular hyperplasia) has been described in a cohort of children with developmental disorder. This study investigates the presence of persistent measles virus in the intestinal tissue of these patients (new variant inflammatory bowel disease) and a series of controls by molecular analysis.

  18. Infantile Short Bowel Syndrome: short and long term evaluation

    NARCIS (Netherlands)

    J.F. Olieman

    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 p

  19. Small Bowel Imaging in Managing Crohn’s Disease Patients

    Directory of Open Access Journals (Sweden)

    Jörg G. Albert

    2012-01-01

    bowel CD, and treatment control with imaging is increasingly used to optimize the patients outcome. Thereby, capsule endoscopy, Balloon-assisted enteroscopy, and Magnetic resonance imaging have become key players to manage CD patients. In this review, role of small bowel imaging is detailed discussed for use in diagnosing and managing Crohn's disease patients.

  20. CT enteroclysis in the diagnostics of small bowel diseases

    International Nuclear Information System (INIS)

    Background: The role of CT enteroclysis is gaining on importance in the diagnostics of small bowel diseases. The aim of the study was to present own experiences in CT enteroclysis application, with the use of a 64-detector CT unit. Material/Methods: CT enteroclyses were performed in 60 patients: 53 with the suspicion of the Crohns disease, 2 suspected for carcinoid, 1 with suspicion of the fistula between the small bowel and the bladder, 2 suspected for the tumor of the ileo-caecal region, and in 1 case, the aim of examination was to carry out an evaluation of the postsurgical state of the bowel-bowel anastomosis. We used own endoscopic technique of catheter insertion into the bowel, which shortens the examination time and improves patients comfort. Results: The catheter was correctly introduced into the small bowel in 58 patients (endoscopy had to be repeated in 4 cases). Only 2 examinations failed, because patients refused repeated endoscopy. Radiological signs of the Crohns disease were found in 50 out of 53 patients. In the 3 remaining patients, the appearance of the small bowel was normal. In 5 non-Crohns disease patients, CT enteroclysis enabled a good visualization of the pathology (tumors, fistula). Conclusions: CT enteroclysis with the use of the 64-detector CT unit is a valuable method in the diagnostics of small bowel diseases. It could supplement or precede capsule endoscopy. (authors)

  1. Childhood Sexual Abuse and Psychosomatic Symptoms in Irritable Bowel Syndrome

    Science.gov (United States)

    Ross, Colin A.

    2005-01-01

    Irritable bowel syndrome is characterized by chronic gastrointestinal symptoms without a demonstrable physical cause. In a subgroup of patients, irritable bowel syndrome may be part of a cluster of psychosomatic symptoms related to childhood sexual abuse. To investigate this possibility, the Dissociative Disorders Interview Schedule (DDIS), the…

  2. Effects of bowel rehabilitation and combined trophic therapy on intestinal adaptation in short bowel patients

    Institute of Scientific and Technical Information of China (English)

    Guo-Hao Wu; Zhao-Han Wu; Zhao-Guang Wu

    2003-01-01

    AIM: To evaluate the effects of bowel rehabilitation and combined trophic therapy on intestinal adaptation in short bowel patients.METHODS: Thirty-eight patients with severe short-bowel syndrome (SBS) were employed in the present study, whose average length of jejunum-ileum was 35.8±21.2 cm. The TPN treatment was initiated early to attain positive nitrogen balance and prevent severe weight loss. The TPN composition was designated to be individualized and altered when necessary. Enteral feeding was given as soon as possible after resection and increased gradually. Meals were distributed throughout the day. Eight patients received treatment of growth hormone (0.14 mg/kg.day) and glutamine (0.3 g/kg.day) for 3 weeks. D-xylose test, 15N-Gly trace test and 13C-palmitic acid breath test were done to determine the patients' absorption capability.RESULTS: Thirty-three patients maintained well body weight and serum albumin concentration. The average time of follow-up for 33 survival patients was 5.9±4.3 years.Twenty-two patients weaned from TPN with an average TPN time of 9.5±6.6 months. Two patients, whose whole small bowel, ascending and transverse colon were resected received home TPN. An other 9 patients received parenteral or enteral nutritional support partly as well as oral diet. Three week rhGH+GLN therapy increased nutrients absorption but the effects were transient.CONCLUSION: By rehabilitation therapy, most short bowel patients could wean from parenteral nutrition. Dietary manipulation is an integral part of the treatment of SBS.Treatment with growth hormone and glutamine may increase nutrients absorption but the effects are not sustained beyond the treatment period.

  3. Inflammatory Bowel Disease: Changing Associations to Mechanisms.

    Science.gov (United States)

    Click, Benjamin; Whitcomb, David C

    2016-01-01

    Managing the health of individual patients suffering from complex disorders is a challenge and is costly. Inflammatory bowel disease (IBD) is a prototypic complex disorder of the small and large intestines. Susceptibility is complex, severity is variable, and response to treatment is unpredictable. Di Narzo et al. (Clin Transl Gastroenterol 7: e177; doi:10.1038/ctg.2016.34) bring diverse teams of physicians and scientists together to break down the mechanisms of IBD by linking pathogenic genetic variants with altered gene expression in specific cell types causing IBD. Framing new findings in the context of other complex diseases provides a roadmap for predictive medicine. PMID:27607898

  4. Immunogenetic phenotypes in inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Marla C Dubinsky; Kent Taylor; Stephan R Targan; Jerome I Rotter

    2006-01-01

    The currently accepted etiopathogenic hypothesis suggests that the chronic intestinal inflammation and related systemic manifestations characteristic of inflammatory bowel disease (IBD) are due to an overly aggressive or pathologic immune response to resident luminal bacterial constituents. Predisposing factors are genetic dysregulation of mucosal immune responses and/or barrier function, with onset triggered by environmental stimuli. These factors and their interactions may also be important determinants of disease phenotype and disease progression. The emergence of immunogenetic phenotypes lends support to the proposed hypothesis that susceptibility genes regulate distinct immune processes, driven by luminal antigens, expressed as specific immune phenotypes which in turn influence clinical phenotypes in IBD patient

  5. Bowel Function in Acute Stroke Patients

    OpenAIRE

    Yi, Jin Hwa; Chun, Min Ho; Kim, Bo Ryun; Han, Eun Young; Park, Ji Young

    2011-01-01

    Objective To investigate factors related to bowel function and colon motility in acute stroke patients. Method Fifty-one stroke patients (29 males, mean age 63.4±13.6 years, onset 13.4±4.8 days) were recruited and divided into two groups: constipation (n=25) and non-constipation (n=26) groups. We evaluated the amount of intake, voiding function, concomitant swallowing problem and colon transit time (CTT) using radio-opaque markers for ascending, descending and rectosigmoid colons. The Adapted...

  6. MR colonography in inflammatory bowel disease.

    Science.gov (United States)

    Rimola, Jordi; Ordás, Ingrid

    2014-02-01

    MR colonography has a high diagnostic accuracy for detecting Crohn disease (CD) activity and determining the extent and severity of lesions. In the setting of stricturing CD, MR colonography can provide a detailed map of the lesions, which is useful for clinical decision making. MR colonography can be used as an alternative to conventional colonoscopy in the setting of CD, or as a complementary tool in selected patients with ulcerative colitis. This article reviews the spectrum of MR colonography findings in colonic inflammatory bowel disease and discusses the potential applications and limitations of MR colonography. PMID:24238130

  7. Inflammatory Bowel Disease and Cervical Neoplasia

    DEFF Research Database (Denmark)

    Rungoe, Christine; Simonsen, Jacob; Riis, Lene; Frisch, Morten; Langholz, Ebbe; Jess, Tine

    2015-01-01

    BACKGROUND & AIMS: We examined the risk of cervical neoplasia (dysplasia or cancer) in women with ulcerative colitis (UC) or Crohn's disease (CD). We also calculated the reverse, the risk for diagnosis with cervical neoplasia before development of inflammatory bowel disease (IBD). METHODS: We...... with IBD were assessed by Cox proportional hazards regression analysis. Odds ratios (ORs) of cervical neoplasia before diagnosis of IBD were calculated by using conditional logistic regression. RESULTS: Women with CD underwent cervical cancer screening as often as women in the general population (IRR...

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

    International Nuclear Information System (INIS)

    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.)

  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. 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

    carried out in addition to MRFT, to which the patients were referred. All patients underwent both examinations on the same day. For the evaluation, the bowel was divided into nine segments. Two radiologists, blinded to clinical findings, evaluated bowel wall thickness, diffusion weighted imaging (DWI...

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

    International Nuclear Information System (INIS)

    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.)

  12. A fast-slow logic system

    International Nuclear Information System (INIS)

    A fast-slow logic system has been made for use in multi-detector experiments in nuclear physics such as particle-gamma and particle-particle coincidence experiments. The system consists of a fast logic system and a slow logic system. The fast logic system has a function of fast coincidences and provides timing signals for the slow logic system. The slow logic system has a function of slow coincidences and a routing control of input analog signals to the ADCs. (auth.)

  13. Management of patients with a short bowel

    Institute of Scientific and Technical Information of China (English)

    Jeremy M D Nightingale

    2001-01-01

    There are two common types of adult patient with a short bowel, those with jejunum in continuity with a functioning colon and those with a jejunostomy. Both groups have potential problems of undemutrition, but this is a greater problem in those without a colon, as they do not derive energy from anaerobic bacterial fermentation of carbohydrate to short chain fatty acids in the colon. Patients with a jejunostomy have major problems of dehydration,sodium and magnesium depletion all due to a large volume of stomal output. Both types of patient have lost at least 60cm of terminal ileum and so will become deficient of vitamin B12. Both groups have a high prevalence of gallstones (45%) resulting from periods of biliary stasis. Patients with a retained colon have a 25% chance of developing calcium oxalats renal atones and they may have problems with D (-)lactic acidosis. The survival of patients with a short bowel,even if they need long-term parenteral nutrition, is good.

  14. Biologic concentration testing in inflammatory bowel disease.

    Science.gov (United States)

    Vaughn, Byron P; Sandborn, William J; Cheifetz, Adam S

    2015-06-01

    Anti-TNF medications have revolutionized the care of patients with inflammatory bowel disease. However, despite an initial robust effect, loss of response is common and long-term results are disappointing. Much of this lack of durability may be due to inadequate dose optimization, and recent studies suggest a correlation between serum drug concentrations and clinical outcomes. Currently, in clinical practice, measurement of drug concentrations and antibodies to drug are typically performed only when a patient presents with active inflammatory bowel disease symptoms or during a potential immune-mediated reaction to anti-TNF ("reactive" setting). However, proactive monitoring of anti-TNF concentrations with titration to a therapeutic window (i.e., therapeutic concentration monitoring) represents a new strategy with many potential clinical benefits including prevention of immunogenicity, less need for IFX rescue therapy, and greater durability of IFX treatment. This review will cover the salient features of anti-TNF pharmacokinetics and pharmacodynamics and provide a rational approach for the use of anti-TNF concentration testing in both the reactive and proactive settings. PMID:25590953

  15. Inflammatory bowel disease: clinical aspects and treatments

    Directory of Open Access Journals (Sweden)

    Fakhoury M

    2014-06-01

    Full Text Available Marc Fakhoury,1 Rebecca Negrulj,2 Armin Mooranian,2 Hani Al-Salami2 1Biomedical Technology and Cell Therapy Research Laboratory, Department of Biomedical Engineering and Artificial Cells and Organs Research Center, Faculty of Medicine, McGill University, Montreal, QC, Canada; 2Biotechnology and Drug Development Research Laboratory, Curtin Health Innovation Research Institute, Biosciences Research Precinct, School of Pharmacy, Curtin University, Perth, WA, Australia Abstract: Inflammatory bowel disease (IBD is defined as a chronic intestinal inflammation that results from host-microbial interactions in a genetically susceptible individual. IBDs are a group of autoimmune diseases that are characterized by inflammation of both the small and large intestine, in which elements of the digestive system are attacked by the body's own immune system. This inflammatory condition encompasses two major forms, known as Crohn's disease and ulcerative colitis. Patients affected by these diseases experience abdominal symptoms, including diarrhea, abdominal pain, bloody stools, and vomiting. Moreover, defects in intestinal epithelial barrier function have been observed in a number of patients affected by IBD. In this review, we first describe the types and symptoms of IBD and investigate the role that the epithelial barrier plays in the pathophysiology of IBD as well as the major cytokines involved. We then discuss steps used to diagnose this disease and the treatment options available, and finally provide an overview of the recent research that aims to develop new therapies for such chronic disorders. Keywords: inflammatory bowel disease, Crohn's disease, ulcerative colitis, cytokines

  16. Nutritional therapy of irritable bowel syndrome.

    Science.gov (United States)

    Friedman, G

    1989-09-01

    Nutritional factors relative to IBS include diagnostic and therapeutic considerations. Etiologically, foods do not cause IBS. A small percentage of patients with childhood allergic diatheses, usually in association with atopic dermatitis and asthma, may be intolerant to one or more of wheat, corn, dairy products, coffee, tea, or citrus fruits. Diagnostically, many patients labeled as IBS subjects are in fact intolerant to the ingestion of lactose-containing foods, sorbitol, fructose, or combinations of fructose and sorbitol. A precise dietary history will characterize this group. Taken in its broadest context, IBS involves the entire hollow tract inclusive of esophagus, stomach, small bowel, and colon. The symptomatic presentation relative to the hollow organ involved allows the selection of dietary manipulations that may help to reduce symptoms. Gastroesophageal reflux, a consequence of low LES pressure in some IBS patients, may be treated with the elimination of fatty foods, alcohol, chocolate, and peppermint. Delayed gastric emptying may be helped by the elimination of fatty foods and reduction of soluble fiber. Aberrant small bowel motor function may be ameliorated by reduction of lactose, sorbitol, and fructose and the addition of soluble fiber. Gas syndromes may be improved by reduced intake of beans, cabbage, lentils, legumes, apples, grapes, and raisins. Colonic motor dysfunction may be overcome by the gradual addition of combinations of soluble and insoluble fiber-containing foods and supplements. The selective use of activated charcoal and simethicone may be helpful. PMID:2553606

  17. Is irritable bowel syndrome an infectious disease?

    Science.gov (United States)

    Thompson, John Richard

    2016-01-28

    Irritable bowel syndrome (IBS) is the most common of all gastroenterological diseases. While many mechanisms have been postulated to explain its etiology, no single mechanism entirely explains the heterogeneity of symptoms seen with the various phenotypes of the disease. Recent data from both basic and clinical sciences suggest that underlying infectious disease may provide a unifying hypothesis that better explains the overall symptomatology. The presence of small intestinal bowel overgrowth (SIBO) has been documented in patients with IBS and reductions in SIBO as determined by breath testing correlate with IBS symptom improvement in clinical trials. The incidence of new onset IBS symptoms following acute infectious gastroenteritis also suggests an infectious cause. Alterations in microbiota-host interactions may compromise epithelial barrier integrity, immune function, and the development and function of both central and enteric nervous systems explaining alterations in the brain-gut axis. Clinical evidence from treatment trials with both probiotics and antibiotics also support this etiology. Probiotics appear to restore the imbalance in the microflora and improve IBS-specific quality of life. Antibiotic trials with both neomycin and rifaximin show improvement in global IBS symptoms that correlates with breath test normalization in diarrhea-predominant patients. The treatment response to two weeks of rifaximin is sustained for up to ten weeks and comparable results are seen in symptom reduction with retreatment in patients who develop recurrent symptoms. PMID:26819502

  18. Psychosocial determinants of irritable bowel syndrome

    Institute of Scientific and Technical Information of China (English)

    Teodora Surdea-Blaga; Adriana Bǎban; Dan L Dumitrascu

    2012-01-01

    From a pure motor disorder of the bowel,in the past few years,irritable bowel syndrome (IBS) has become a multifactorial disease that implies visceral hypersensitivity,alterations at the level of nervous and humoral communications between the enteric nervous system and the central nervous system,alteration of the gut microflora,an increased intestinal permeability and minimum intestinal inflammation.Psychological and social factors can interfere with the communication between the central and enteric nervous systems,and there is proof that they are involved in the onset of IBS and influence the response to treatment and outcome.There is evidence that abuse history and stressful life events are involved in the onset of functional gastrointestinal disorders.In order to explain clustering of IBS in families,genetic factors and social learning mechanisms have been proposed.The psychological features,such as anxiety,depression as well as the comorbid psychiatric disorders,health beliefs and coping of patients with IBS are discussed in relation to the symptoms and outcome.

  19. Bacteria, genetics and irritable bowel syndrome.

    LENUS (Irish Health Repository)

    Craig, Orla F

    2010-06-01

    EVALUATION OF: Villani AC, Lemire M, Thabane M et al. Genetic risk factors for post-infectious irritable bowel syndrome following a waterborne outbreak of gastroenteritis. Gastroenterology 138, 1502-1513 (2010). While the pathogenesis of irritable bowel syndrome (IBS) remains to be fully defined, two clinical observations - the occurrence, de novo, of IBS following bacterial gastroenteritis and the history, commonly obtained from IBS patients, of other instances of the syndrome within their families - have instigated investigations, in IBS, of the potential roles, on the one hand, of the gut microbiota and the host response and, on the other hand, of genetic factors. The study reviewed here relates to both of these factors by studying genetic predisposition to postinfective IBS in a large population of individuals who were exposed to a multimicrobial enteric infection, which resulted in a severe outbreak of gastroenteritis and was followed by the development of IBS in over a third. In this detailed study, the investigators identified a number of genes that were linked significantly to the development of postinfectious-IBS in the Toll-like receptor 9, IL-6 and cadherin 1 regions. These genes play important roles in bacterial recognition, the inflammatory response and epithelial integrity, respectively, and provide considerable support for the hypothesis that links IBS onset to disturbances in the microbiota and the host response.

  20. Structural brain lesions in inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Can; Dolapcioglu; Hatice; Dolapcioglu

    2015-01-01

    Central nervous system(CNS) complications or manifes-tations of inflammatory bowel disease deserve particular attention because symptomatic conditions can require early diagnosis and treatment, whereas unexplained manifestations might be linked with pathogenic me-chanisms. This review focuses on both symptomatic and asymptomatic brain lesions detectable on imaging studies, as well as their frequency and potential mecha-nisms. A direct causal relationship between inflammatory bowel disease(IBD) and asymptomatic structural brain changes has not been demonstrated, but several possible explanations, including vasculitis, thromboembolism and malnutrition, have been proposed. IBD is associated with a tendency for thromboembolisms; therefore, cerebro-vascular thromboembolism represents the most frequent and grave CNS complication. Vasculitis, demyelinating conditions and CNS infections are among the other CNS manifestations of the disease. Biological agents also represent a risk factor, particularly for demyelination. Identification of the nature and potential mechanisms of brain lesions detectable on imaging studies would shed further light on the disease process and could improve patient care through early diagnosis and treatment.