Bibliographies thématiques / D-wave monitoring

Littérature scientifique sur le sujet « D-wave monitoring »

Auteur : Grafiati
Publié le 11 mars 2023

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Articles de revues sur le sujet "D-wave monitoring"

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Fukaya, C., M. Watanabe, K. Sumi, T. Otaka, K. Shijo, T. Nagaoka, K. Kobayashi, H. Oshima, T. Yamamoto et Y. Katayama. « S28-3 D-wave monitoring in brain tumor surgery ». Clinical Neurophysiology 121 (octobre 2010) : S44. http://dx.doi.org/10.1016/s1388-2457(10)60183-6.

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Ghadirpour, Reza, Davide Nasi, Corrado Iaccarino, Antonio Romano, Luisa Motti, Rossella Sabadini, Franco Valzania et Franco Servadei. « Intraoperative neurophysiological monitoring for intradural extramedullary spinal tumors : predictive value and relevance of D-wave amplitude on surgical outcome during a 10-year experience ». Journal of Neurosurgery : Spine 30, no 2 (février 2019) : 259–67. http://dx.doi.org/10.3171/2018.7.spine18278.

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OBJECTIVEThe purpose of this study was to evaluate the technical feasibility, accuracy, and relevance on surgical outcome of D-wave monitoring combined with somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) during resection of intradural extramedullary (IDEM) spinal tumors.METHODSClinical and intraoperative neurophysiological monitoring (IONM) data obtained in 108 consecutive patients who underwent surgery for IDEM tumors at the Institute for Scientific and Care Research “ASMN” of Reggio Emilia, Italy, were prospectively entered into a database and retrospectively analyzed. The IONM included SSEPs, MEPs, and—whenever possible—D-waves. All patients were evaluated using the modified McCormick Scale at admission and at 3, 6, and 12 months of follow-up .RESULTSA total of 108 patients were included in this study. A monitorable D-wave was achieved in 71 of the 77 patients harboring cervical and thoracic IDEM tumors (92.2%). Recording of D-waves in IDEM tumors was significantly associated only with a preoperative deeply compromised neurological status evaluated using the modified McCormick Scale (p = 0.04). Overall, significant IONM changes were registered in 14 (12.96%) of 108 patients and 9 of these patients (8.33%) had permanent loss of at least one of the 3 evoked potentials. In 7 patients (6.48%), the presence of an s18278 caudal D-wave was predictive of a favorable long-term motor outcome even when the MEPs and/or SSEPs were lost during IDEM tumor resection. However, in 2 cases (1.85%) the D-wave permanently decreased by approximately 50%, and surgery was definitively abandoned to prevent permanent paraplegia. Cumulatively, SSEP, MEP, and D-wave monitoring significantly predicted postoperative deficits (p = 0.0001; AUC = 0.905), with a sensitivity of 85.7% and a specificity of 97%. Comparing the area under the receiver operating characteristic curves of these tests, D-waves appeared to have a significantly greater predictive value than MEPs and especially SSEPs alone (0.992 vs 0.798 vs 0.653; p = 0.023 and p < 0.001, respectively). On multiple logistic regression, the independent risk factors associated with significant IONM changes in the entire population were age older than 65 years and an anterolateral location of the tumor (p < 0.0001).CONCLUSIONSD-wave monitoring was feasible in all patients without severe preoperative motor deficits. D-waves demonstrated a statistically significant higher ability to predict postoperative deficits compared with SSEPs and MEPs alone and allowed us to proceed with IDEM tumor resection, even in cases of SSEP and/or MEP loss. Patients older than 65 years and with anterolateral IDEM tumors can benefit most from the use of IONM.
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Fujiki, Minoru, Yoshie Furukawa, Tohru Kamida, Mitsuhiro Anan, Ryo Inoue, Tatsuya Abe et Hidenori Kobayashi. « Intraoperative corticomuscular motor evoked potentials for evaluation of motor function : a comparison with corticospinal D and I waves ». Journal of Neurosurgery 104, no 1 (janvier 2006) : 85–92. http://dx.doi.org/10.3171/jns.2006.104.1.85.

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Object The goal of this study was to compare motor evoked potentials recorded from muscles (muscle MEPs or corticomuscular MEPs) with corticospinal MEPs recorded from the cervical epidural space (spinal MEPs or corticospinal MEPs) to assess their efficacy in the intraoperative monitoring of motor function. Methods Muscle and spinal MEPs were simultaneously recorded during surgery in 80 patients harboring brain tumors. Each case was assigned to one of four groups according to final changes in the MEPs: 1) Group A, in which there was an increased amplitude in the muscle MEP with an increased I3 wave amplitude (12 cases); 2) Group B, in which there was no significant change in the MEP (43 cases); 3) Group C, in which there was a decreased muscle MEP amplitude (< 35% of the control) with a decreased I wave amplitude but an unchanged D wave (15 cases); or 4) Group D, in which there was an absent muscle MEP with a decreased D wave amplitude (10 cases). In patients in Group A, the increase in the amplitude of the muscle MEP (range of increase 128–280%, mean increase 188.75 ± 48.79%) was well correlated with the increase in the I3 wave in corticospinal MEPs. Most of these patterns were observed in patients harboring meningiomas (10 [83.3%] of 12 cases). Patients in Group B displayed no changes in muscle and corticospinal MEPs and no signs of postoperative neurological deterioration. Patients in Group C showed a substantial decrease in the amplitude of the muscle MEP (range of decrease 5.3–34.8% based on the control waveform, mean change 21.81 ± 10.93%) without deterioration in the corticospinal D wave, and exhibited severe immediate postoperative motor dysfunction. This indicates dysfunction of the cortical gray matter, including the motor cortices, which are supposed to generate I waves. Patients in Group D exhibited decreases in the corticospinal D wave (range of decrease 21.5–55%, mean decrease 39.75 ± 11.45%) and an immediate cessation of the muscle MEP as well as severe permanent motor paresis. Conclusions These results indicate that, during surgery, monitoring of corticomuscular MEPs (which are related to I waves) is a much more sensitive method for the detection of immediate motor cortical damage than monitoring of corticospinal MEPs (D wave).
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Mordret, Aurélien, Roméo Courbis, Florent Brenguier, Małgorzata Chmiel, Stéphane Garambois, Shujuan Mao, Pierre Boué et al. « Noise-based ballistic wave passive seismic monitoring – Part 2 : surface waves ». Geophysical Journal International 221, no 1 (18 février 2020) : 692–705. http://dx.doi.org/10.1093/gji/ggaa016.

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SUMMARY We develop a new method to monitor and locate seismic velocity changes in the subsurface using seismic noise interferometry. Contrary to most ambient noise monitoring techniques, we use the ballistic Rayleigh waves computed from 30 d records on a dense nodal array located above the Groningen gas field (the Netherlands), instead of their coda waves. We infer the daily relative phase velocity dispersion changes as a function of frequency and propagation distance with a cross-wavelet transform processing. Assuming a 1-D velocity change within the medium, the induced ballistic Rayleigh wave phase shift exhibits a linear trend as a function of the propagation distance. Measuring this trend for the fundamental mode and the first overtone of the Rayleigh waves for frequencies between 0.5 and 1.1 Hz enables us to invert for shear wave daily velocity changes in the first 1.5 km of the subsurface. The observed deep velocity changes (±1.5 per cent) are difficult to interpret given the environmental factors information available. Most of the observed shallow changes seem associated with effective pressure variations. We observe a reduction of shear wave velocity (–0.2 per cent) at the time of a large rain event accompanied by a strong decrease in atmospheric pressure loading, followed by a migration at depth of the velocity decrease. Combined with P-wave velocity changes observations from a companion paper, we interpret the changes as caused by the diffusion of effective pressure variations at depth. As a new method, noise-based ballistic wave passive monitoring could be used on several dynamic (hydro-)geological targets and in particular, it could be used to estimate hydrological parameters such as the hydraulic conductivity and diffusivity.
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Knafo, William. « COVID-19 : Monitoring the propagation of the first waves of the pandemic ». 4open 3 (2020) : 5. http://dx.doi.org/10.1051/fopen/2020005.

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Introduction: A phenomenological approach is proposed to monitor the propagation of the first waves of the COVID-19 pandemic. Method: A large set of data collected during the first months of 2020 is compiled into a series of semi-logarithmic plots, for a selection of 32 countries from the five continents. Results: Three regimes are identified in the propagation of an epidemic wave: a pre-epidemic regime 1, an exponential-growth regime 2, and a resorption regime 3. A two-parameters scaling of the first-wave death variation reported in China is used to fit the first-wave data reported in other countries. Comparison is made between the propagation of the pandemic in different countries, which are classified into four groups, from Group A where the pandemic first waves were contained efficiently, to Group D where the pandemic first waves widely spread. All Asian countries considered here, where fast and efficient measures have been applied, are in Group A. Group D is composed of Western-European countries and the United States of America (USA), where late decisions and confused political communication (pandemic seriousness, protection masks, herd immunity, etc.) led to a large number of deaths. Discussion: The threat of resurging epidemic waves following a lift of lockdown measures is discussed. The results obtained in Asian countries from group A, as Hong Kong and South Korea, are highlighted, and the measures taken there are presented as examples that other countries may follow.
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He, Wen, Changsong Zheng, Shenhai Li, Wenfang Shi et Kui Zhao. « Strength Development Monitoring of Cemented Paste Backfill Using Guided Waves ». Sensors 21, no 24 (20 décembre 2021) : 8499. http://dx.doi.org/10.3390/s21248499.

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The strength of cemented paste backfill (CPB) directly affects mining safety and progress. At present, in-situ backfill strength is obtained by conducting uniaxial compression tests on backfill core samples. At the same time, it is time-consuming, and the integrity of samples cannot be guaranteed. Therefore guided wave technique as a nondestructive inspection method is proposed for the strength development monitoring of cemented paste backfill. In this paper, the acoustic parameters of guided wave propagation in the different cement-tailings ratios (1:4, 1:8) and different curing times (within 42 d) of CPBs were measured. Combined with the uniaxial compression strength of CPB, relationships between CPB strength and the guided wave acoustic parameters were established. Results indicate that with the increase of backfill curing time, the guided wave velocity decreases sharply at first; on the contrary, attenuation of guided waves increases dramatically. Finally, both velocity and attenuation tend to be stable. When the CPB strength increases with curing time, guided wave velocity shows an exponentially decreasing trend, while the guided wave attenuation shows an exponentially increasing trend with the increase of the CPB strength. Based on the relationship curves between CPB strength and guided wave velocity and attenuation, the guided wave technique in monitoring the strength development of CPB proves feasible.
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Barzilai, Ori, Zvi Lidar, Shlomi Constantini, Khalil Salame, Yifat Bitan-Talmor et Akiva Korn. « Continuous mapping of the corticospinal tracts in intramedullary spinal cord tumor surgery using an electrified ultrasonic aspirator ». Journal of Neurosurgery : Spine 27, no 2 (août 2017) : 161–68. http://dx.doi.org/10.3171/2016.12.spine16985.

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Intramedullary spinal cord tumors (IMSCTs) represent a rare entity, accounting for 4%–10% of all central nervous system tumors. Microsurgical resection of IMSCTs is currently considered the primary treatment modality. Intraoperative neurophysiological monitoring (IONM) has been shown to aid in maximizing tumor resection and minimizing neurological morbidity, consequently improving patient outcome. The gold standard for IONM to date is multimodality monitoring, consisting of both somatosensory evoked potentials, as well as muscle-based transcranial electric motor evoked potentials (tcMEPs). Monitoring of tcMEPs is optimal when combining transcranial electrically stimulated muscle tcMEPs with D-wave monitoring. Despite continuous monitoring of these modalities, when classic monitoring techniques are used, there can be an inherent delay in time between actual structural or vascular-based injury to the corticospinal tracts (CSTs) and its revelation. Often, tcMEP stimulation is precluded by the surgeon’s preference that the patient not twitch, especially at the most crucial times during resection. In addition, D-wave monitoring may require a few seconds of averaging until updating, and can be somewhat indiscriminate to laterality. Therefore, a method that will provide immediate information regarding the vulnerability of the CSTs is still needed.The authors performed a retrospective series review of resection of IMSCTs using the tip of an ultrasonic aspirator for continuous proximity mapping of the motor fibers within the spinal cord, along with classic muscle-based tcMEP and D-wave monitoring.The authors present their preliminary experience with 6 patients who underwent resection of an IMSCT using the tip of an ultrasonic aspirator for continuous proximity mapping of the motor fibers within the spinal cord, together with classic muscle-based tcMEP and D-wave monitoring. This fusion of technologies can potentially assist in optimizing resection while preserving neurological function in these challenging surgeries.
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Kalgutkar, AkshayPrakash, et Sauvik Banerjee. « Semi-Analytical Finite Element Method for the Analysis of Guided Wave Dispersion in the Pre-stressed Composite Plates ». Proceedings of the 12th Structural Engineering Convention, SEC 2022 : Themes 1-2 1, no 1 (19 décembre 2022) : 1413–21. http://dx.doi.org/10.38208/acp.v1.671.

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Ultrasonic guided wave techniques offer an accurate and efficient procedure for damage monitoring in the structures. To develop reliable damage monitoring systems, it is essential to have a thorough understanding of the quantitative nature of ultrasonic guided waves that can be transmitted in composite laminates. In the present paper, the Semi-Analytical Finite Element (SAFE) method is employed due to its efficiency in the treatment of wave propagation problems involving complex materials and geometry. SAFE method is considered for the analysis of dispersion behaviour of guided waves in composite laminates by accounting the effect of in-plane load. The present study considers an infinite width plate such that the cross-section of the waveguide is modelled using 3 noded isoparametric 1-D elements representing the thickness of the plate. Equation of motion is formulated by using Hamilton’s equation. Finally, various parametric studies are carried out. The study includes analysing the effect of wave velocity in the plate subjected to applied in-plane load, and understanding the effect of dispersion characteristics on the direction of propagation (slowness curve). The study shows that at the lower frequency thickness product, the group velocity of the wave increases with the increase in the applied tensile load and vice-versa.
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Sun, Ya Jie, Yong Hong Zhang, Cheng Shan Qian, Zi Jia Zhang et Qi Wang. « 3-D Imaging Based Ultrasonic Phased Array Theory for Composite Structure Damage Identification ». Applied Mechanics and Materials 389 (août 2013) : 881–86. http://dx.doi.org/10.4028/www.scientific.net/amm.389.881.

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The Lamb wave phased array theory is utilized to analysis the damage scattered signals to identify the structure defect. The damage scattered signals are gotten by comparing the health signals with the damage signals. Phased array theory based structural health monitoring can scan the structure in a certain range of 0°~180° by controlling the time delay of the excitation signals and the response signals. The processed signals in monitoring direction is shown on 3-D imaging to express the damage location in the structure. The method is verified by the experiment on the composite structure and the result shows that the Lamb wave phased array method can detect the damage in the composite structure and the 3-D image clearly displays the structure damage location.
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Luo, Bin, Whitney Trainor-Guitton, Ebru Bozdağ, Lisa LaFlame, Steve Cole et Martin Karrenbach. « Horizontally orthogonal distributed acoustic sensing array for earthquake- and ambient-noise-based multichannel analysis of surface waves ». Geophysical Journal International 222, no 3 (16 juin 2020) : 2147–61. http://dx.doi.org/10.1093/gji/ggaa293.

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SUMMARY A 2-D orthogonal distributed acoustic sensing (DAS) array designed for seismic experiments was buried horizontally beneath the Kafadar Commons Geophysical Laboratory on the Colorado School of Mines campus at Golden, Colorado. The DAS system using straight fibre-optic cables is a cost-efficient technology that enables dense seismic array deployment for long-term seismic monitoring, favouring both earthquake-based and ambient-noise-based surface wave analysis for subsurface characterization. In our study, the horizontally orthogonal DAS array records ambient noise data for a period of about two months from November 2018 to January 2019. During this time, the array also detected seismic signals from an ML3.6 earthquake at Glenwood Springs, Colorado, which exhibit opposite signal polarities in the orthogonal DAS section recordings. We derive the transformation matrix for DAS strain measurements in horizontally orthogonal cables to retrieve both Rayleigh and Love wave dispersion information from the single-component DAS signals using the 2-D multichannel analysis of surface waves method. In addition, ambient noise interferometry is applied to long-term DAS noise recordings. Our theoretical derivation demonstrates that Rayleigh and Love wave Green's functions are coupled in the noise cross-correlation functions (NCFs) of DAS receiver pairs. Stacking NCFs over the horizontally orthogonal DAS array can constructively recover the radial Rayleigh wave component but destructively suppress the Love wave component. The multimodal Monte Carlo inversion of the earthquake-based Rayleigh wave and Love wave dispersion measurements and the noise-based Rayleigh wave measurement reveals a 1-D layered structure that agrees qualitatively with geological surveys of the site. Our study demonstrates that although straight fibre-optic cables lack broadside sensitivity, using appropriate DAS array configuration and seismic array methods can extend the seismic acquisition ability of DAS and enable its application to a broad range of scenarios.
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Thèses sur le sujet "D-wave monitoring"

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Reinhardt, Alwin [Verfasser]. « A Millimeter Wave Radar Sensor for Monitoring Solid and Liquid Aerosol Streams / Alwin Reinhardt ». Düren : Shaker, 2019. http://d-nb.info/1202218806/34.

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Ebna, Hai Bhuiyan Shameem Mahmood [Verfasser]. « Finite Element Approximation of Ultrasonic Wave Propagation under Fluid-Structure Interaction for Structural Health Monitoring Systems / Bhuiyan Shameem Mahmood Ebna Hai ». Hamburg : Helmut-Schmidt-Universität, Bibliothek, 2017. http://d-nb.info/1148436170/34.

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Fallahi, Mohammad Javad [Verfasser], et Michael [Gutachter] Korn. « Surface wave tomography and monitoring of time variations with ambient noise in NW-Bohemia/Vogtland / Mohammad Javad Fallahi ; Gutachter : Michael Korn ». Leipzig : Universitätsbibliothek Leipzig, 2016. http://d-nb.info/124024231X/34.

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Schulte, Rolf T. [Verfasser]. « Modellierung und Simulation von wellenbasierten Structural-Health-Monitoring-Systemen mit der Spektral-Elemente-Methode. Modelling and simulation of wave-based structural health monitoring-systems using the spectral element method / Rolf T. Schulte ». Siegen : Universitätsbibliothek Siegen, 2011. http://d-nb.info/1010297430/34.

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Willberg, Christian Verfasser], et Ulrich [Akademischer Betreuer] [Gabbert. « Development of a new isogeometric finite element and its application for Lamb wave based structural health monitoring / Christian Willberg. Betreuer : Ulrich Gabbert ». Magdeburg : Universitätsbibliothek, 2012. http://d-nb.info/1054135924/34.

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Boxberg, Marc Sebastian [Verfasser], Wolfgang [Gutachter] Friedrich, Holger [Gutachter] Steeb et Michael [Gutachter] Alber. « Simulation of seismic wave propagation in porous rocks considering the exploration and the monitoring of geological reservoirs / Marc Sebastian Boxberg ; Gutachter : Wolfgang Friedrich, Holger Steeb, Michael Alber ; Fakultät für Geowissenschaften ». Bochum : Ruhr-Universität Bochum, 2019. http://d-nb.info/1202608957/34.

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Livres sur le sujet "D-wave monitoring"

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Deletis, Vedran, Francesco Sala et Sedat Ulkatan. Transcranial electrical stimulation and intraoperative neurophysiology of the corticospinal tract. Sous la direction de Charles M. Epstein, Eric M. Wassermann et Ulf Ziemann. Oxford University Press, 2012. http://dx.doi.org/10.1093/oxfordhb/9780198568926.013.0008.

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Transcranial electrical stimulation is a well-recognized method for corticospinal tract (CT) activation. This article explains the use of TES during surgery and highlights the physiology of the motor-evoked potentials (MEPs). It describes the techniques and methods for brain stimulation and recording of responses. There are two factors that determine the depth of the current penetrating the brain, they are: choice of electrode montage for stimulation over the scalp and the intensity of stimulation. D-wave collision technique is a newly developed technique that allows mapping intraoperatively and finding the anatomical position of the CT within the surgically exposed spinal cord. Different mechanisms may be involved in the pathophysiology of postoperative paresis in brain and spinal cord surgeries so that different MEP monitoring criteria can be used to avoid irreversible damage and accurately predict the prognosis.
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Daudon, Michel, et Paul Jungers. Cystine stones. Sous la direction de Mark E. De Broe. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199592548.003.0203_update_001.

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Cystinuria, an autosomal recessive disease (estimated at 1:7000 births worldwide), results from the defective reabsorption of cystine and dibasic amino acids (also ornithine, arginine, lysine, COAL) by epithelial cells of renal proximal tubules, leading to an abnormally high urinary excretion of these amino acids. Due to the poor solubility of cystine at the usual urine pH, formation of cystine crystals and stones ensues. Incidence of homozygotes is estimated at 1 in 7000 births worldwide, but is lower in European countries and much higher in populations with frequent consanguinity. Cystine stones represent 1–2% of all stones in adults and 5–8% in paediatric patients, with an equal distribution between males and females.Cystinuria is caused by inactivating mutations in the gene SLC3A1 or SLC7A9, both encoding proteins contributing to the function of the heterodimeric transport system of cystine.Cystine nephrolithiasis may present in infants, most frequently in adolescents or young adults, sometimes later. Cystine calculi are weakly radio-opaque. Stone analysis using infrared spectroscopy (or X-ray diffraction) allows immediate and accurate diagnosis. Urinary amino acid chromatography quantifies urinary cystine excretion, needed to define the therapeutic strategy.Urological treatment of cystine stones currently uses extracorporeal stone wave lithotripsy or flexible ureterorenoscopy with Holmium laser, that is, minimally invasive techniques. However, as cystine stones are highly recurrent, preventive therapy is essential.Medical treatment combines reduced methionine and sodium intake, to lower cystine excretion; hyperdiuresis (> 3 L/day) to reduce cystine concentration; and active alkalinization preferably using potassium citrate (40–80 mEq/day) to increase cystine solubility by rising urine pH up to 7.5–8. If these measures are insufficient to prevent recurrent stone formation, a thiol derivative (D-penicillamine or tiopronin), which converts cystine into a more soluble disulphide, should be added. Close monitoring and adherence of the patient to the therapeutic programme are needed to ensure life-long compliance, the key for successful prevention in the long term.
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Chapitres de livres sur le sujet "D-wave monitoring"

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Katayama, Y., T. Tsubokawa, T. Yamamoto, T. Hirayama et S. Maejima. « Separation of upper and lower extremity components of the corticospinal MEP (D-wave) recorded at the cervical level ». Dans Handbook of Spinal Cord Monitoring, 312–20. Dordrecht : Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1416-5_45.

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Katayama, Y., T. Tsubokawa, T. Yamamoto, T. Hirayama et S. Maejima. « Changes in the corticospinal MEP (D-wave) during microsurgical removal of intramedullary spinal cord tumours : experience in 16 cases ». Dans Handbook of Spinal Cord Monitoring, 321–26. Dordrecht : Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1416-5_46.

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Mauricio, Elizabeth A. « Motor Evoked Potentials ». Dans Clinical Neurophysiology, sous la direction de Devon I. Rubin, 747–60. 5e éd. Oxford University PressNew York, 2021. http://dx.doi.org/10.1093/med/9780190067854.003.0041.

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Abstract Motor evoked potentials can be generated by either electrical or magnetic stimulation of the corticospinal pathways. Direct activation of pyramidal cells and indirect activation of cortical interneurons generate impulses that propagate down the spinal cord as D-waves and I-waves, ultimately stimulating anterior horn cells and resulting in M-waves recorded over the targeted muscle. Transcranial electrical stimulation is most commonly employed in the operating room for intraoperative neurophysiologic monitoring, ensuring that the integrity of the motor pathways are preserved during brain or spine surgeries. The utility of transcranial magnetic stimulation has been explored in many neurologic diseases, where alterations in central motor conduction time and cortical excitability may provide important clues in diagnosis, prognosis, and monitoring response to treatment.
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Hoffman, E. Matthew. « Spinal Cord and Root Monitoring ». Dans Clinical Neurophysiology, sous la direction de Devon I. Rubin, 957–76. 5e éd. Oxford University PressNew York, 2021. http://dx.doi.org/10.1093/med/9780190067854.003.0055.

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Abstract Intraoperative neurophysiological monitoring (IONM) is the application of neurophysiologic tests as a surrogate for neurologic function during surgery wherein loss of neurophysiologic potentials indicates likely neurologic injury. Spinal cord IONM during vertebral column surgery is the most prevalent situation where these techniques are applied. This chapter discusses common electrophysiological modalities useful for spinal cord and spinal nerve root monitoring, including somatosensory evoked potentials, motor evoked potentials, D-waves, and electromyography. Spinal cord and nerve root injury can be detected by multimodality IONM. The selection of which modalities and which nerve/muscle combinations to use needs to be tailored to the each surgery. Given the variety of practice models, intraoperative monitoring physicians must strive to maintain excellent communication with and situational awareness of the operating rooms they are working in, even when working remotely.
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Deletis, Vedran, et Francesco Sala. « Corticospinal tract monitoring with D‐ and I‐waves from the spinal cord and muscle MEPs from limb muscles ». Dans Intraoperative Monitoring of Neural Function, 235–51. Elsevier, 2008. http://dx.doi.org/10.1016/s1567-4231(07)08016-1.

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Actes de conférences sur le sujet "D-wave monitoring"

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LI, CHENG, ZELIANG LIU, MING LI, HUNGGUANG LI, YING LI et WING KAM LIU. « Subharmonic Resonance of Geometrical Nonlinear Structure in 2-D Periodic Elastic System for Mechanical Wave Filtering ». Dans Structural Health Monitoring 2015. Destech Publications, 2015. http://dx.doi.org/10.12783/shm2015/133.

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RAI, AKSHAY, et MIRA MITRA. « A MULTI-HEADED CNN FRAMEWORK FOR LAMB WAVE-BASED DAMAGE DETECTION IN A THIN ALUMINUM PLATE ». Dans Structural Health Monitoring 2021. Destech Publications, Inc., 2022. http://dx.doi.org/10.12783/shm2021/36272.

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In this research, a deep learning framework of 1D-Convolutional neural networks (CNNs) is utilized to recognize and auto-extract damage related features within the fragments of raw 1-D Lamb wave data. To analyze the performance of the proposed network, a diverse database is constructed to train and test the 1D-CNN architecture. It contains Lamb waves time-series data recorded from both 24 experimental and 216 Finite Element (FE) simulation setups of 1.6 mm thin Al-5052 plate. To scan the platestructure, a pitch-catch transducers configuration is adopted. The actuator-transducer excites 3.5 cycles modulated sinusoidal tone-burst signal at three different frequencies i.e., 100 kHz, 125 kHz and 150 kHz and the corresponding responses are collected from sensor-transducer only. An anomaly is introduced in the FE model in the form of a 0.8 mm deep and 2 mm wide notch-like cavity. Whereas, the damage in the experimental setup is realized by attaching an external mass of 14 gm in the center of the PZTs. Next, a 1D-CNN architecture is designed that uses raw 1D Lamb wave signals as an input and can capture high-level damage related features from the raw Lamb wave signals. Then the CNN model is trained on 90% of the total number of samples in the database using the Adam algorithm. At a later stage, the trained 1D-CNN architecture performance is validated against the 24 unseen Lamb wave responses. Out of the 24 unseen samples, the proposed architecture decisively predicts the outcome for 23 samples. This test against the unseen experimentally generated samples proves that the proposed deep learning framework has achieved the required generalization over the real scenario.
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Raghavan, Ajay, et Carlos Cesnik. « 3-D Elasticity-based Modeling of Anisotropic Piezocomposite Transducers for Guided Wave Structural Health Monitoring ». Dans 47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
14th AIAA/ASME/AHS Adaptive Structures Conference
7th. Reston, Virigina : American Institute of Aeronautics and Astronautics, 2006. http://dx.doi.org/10.2514/6.2006-1793.

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Salas, Ken I., et Carlos E. S. Cesnik. « Design of Variable-Length Piezocomposite Transducer for Structural Health Monitoring ». Dans ASME 2008 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2008. http://dx.doi.org/10.1115/smasis2008-385.

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A modally-selective, variable-length anisotropic piezocomposite transducer is designed for guided wave (GW) structural health monitoring applications. The transducer dimensions needed to maximize individual modes are selected based on 3-D elasticity models for GW excitation by finite dimensional transducers. This theory is used to determine these transducer dimensions as a function of the wave phase velocity, and normalized by the substrate thickness. The design and fabrication of the transducer are subsequently described, and a set of experimental tests is conducted in pristine isotropic structures to characterize the actuation and sensing performance of the device. It is shown that the transducer dimensions can be tailored to obtain specific symmetric to antisymmetric mode transmission ratios.
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Yoo, Byungseok, Darryll J. Pines et Ashish S. Purekar. « Multi-Location Actuators and Piezoceramic Based 2-D Spiral Array for Structural Health Monitoring : Thin Isotropic Panels ». Dans ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2010. http://dx.doi.org/10.1115/smasis2010-3723.

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In this paper, a new and robust 2-D phased array technique with multiple distributed actuators is studied for damage detection application based on Guided Lamb Wave (GLW) interrogation in a thin isotropic panel. A 2-D phased array technique using a single actuator located near the center of the 2-D phased array is unable to detect a linear crack oriented normal to the wavefront of the GLW excited from the actuator. To overcome this limitation, the 2-D phased array is coupled with multiple actuators in this study where the actuators are positioned at various locations on a test panel while the 2-D phased array is mounted at the center of the panel. A piezoceramic based 2-D phased array with a spiral configuration is used as a sensor array and the corresponding 2-D phased array signal processing is used to produce array responses and detect various damages. An innovative GLW propagation and reflection analysis technique is implemented to evaluate the damage locations in the panel. Experimental results demonstrate that the 2-D phased array damage detection technique using multiple distributed actuators can provide more robust damage detection scheme in thin isotropic panels than a technique with a single actuator element.
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Bogdanovich, Alexander, Donald Wigent, Thomas J. Whitney et Paul A. Clark. « 3-D Woven Composites Instrumented With EFPI Fiber Optic Sensors ». Dans ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33480.

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A novel approach to continuous health monitoring of polymeric composite materials and structural elements using embedded Extrinsic Fabry-Perot Interferometers (EFPI) is proposed and validated. The proof of concept includes several consecutive steps. First, it is verified that simple optical wave guides survived a regular 3-D weaving process. Then EFPI sensor assemblies are manually incorporated into the preforms and it is verified that they are functional. Next step is resin infusion of instrumented preforms using VARTM method, followed by investigation of possible mechanical damage to sensor leads. Finally, test specimens are fabricated, and four-point bending tests are performed. The internal strain monitoring results provided by the embedded fiber optic sensors are compared to the data from surface foil gages. The developed approach validates, particularly, the possibility of continuous through-thickness strain monitoring, which is crucial for composite bonded and bolted joints, components with holes, openings, stiffeners, and other cases of high strain gradients.
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Nucera, Claudio, et Francesco Lanza di Scalea. « Nonlinear Guided Waves for Structural Health Monitoring : Numerical Algorithm and Application to Railroad Track ». Dans ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/smasis2012-8139.

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The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is conducting research to develop a system for in-situ measurement of the rail Neutral Temperature in Continuous-Welded Rail (CWR). It is known that CWR can break in cold weather and can buckle in hot weather. Currently, there is a need for the railroads to know the current state of thermal stress in the rail, or the rail Neutral Temperature (rail temperature with zero thermal stress), to properly schedule slow-order mandates and prevent derailments. UCSD has developed a prototype for wayside rail Neutral Temperature measurement that is based on non-linear ultrasonic guided waves. Numerical models were first developed to identify proper guided wave modes and frequencies for maximum sensitivity to the thermal stresses in the rail web, with little influence of the rail head and rail foot. Experiments conducted at the Large-scale Rail NT Test-bed indicated a rail Neutral Temperature measurement accuracy of a few degrees. Field tests are planned at the Transportation Technology Center (TTC) in Pueblo, CO in June 2012 in collaboration with the Burlington Northern Santa Fe (BNSF) Railway.
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Bellam Muralidhar, Nanda Kishore, et Dirk Lorenz. « A Model-Based Damage Identification using Guided Ultrasonic Wave Propagation in Fiber Metal Laminates ». Dans VI ECCOMAS Young Investigators Conference. València : Editorial Universitat Politècnica de València, 2021. http://dx.doi.org/10.4995/yic2021.2021.12684.

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Fiber metal laminates (FML) are lightweight hybrid structural materials that combine the ductile properties of metal with high specific stiffness of fiber reinforced plastics. These advantages led to a dramatic increase in such materials for aeronautical structures over the last few years. One of the most common and vulnerable defects in FML is impact-related delamination, often invisible to the human eye. Guided ultrasonic waves (GUW) show high potential for monitoring structural integrity and damage detection in thin-walled structures by using the physical phenomena of wave propagation interacting with the defects [1]. The focus of this research project is on describing an inverse solution for the detection and characterization of defect in FML. Model-based damage analysis utilizes an accurate finite element model (FEM) of GUW interaction with the damage. The FEM is developed by project partners from mechanics at Helmut-Schmidt-University in Hamburg, Germany, and will be treated as a black-box for further analysis. A Bayesian approach (Markov chain Monte Carlo) is employed to characterize the damage and quantify its uncertainties. This inference problem in a stochastic framework requires a very large number of forward solves. Therefore, a profound investigation is carried out on different reduced-order modeling (ROM) methods in order to apply a suitable technique that significantly improves the computational efficiency. The proposed method is well illustrated on a simpler case study for the damage detection, localization and characterization using 2D elastic wave equation. The damage in this case is modeled as a reduction in the wave propagation velocity. The inference problem utilizes a parameterized projection-based ROM coupled with a surrogate model [2] instead of the underlying highdimensional model. This research is funded by the Deutsche Forschungsgemeinschaft Research Unit 3022 under grant LO1436/12-1.REFERENCES [1] R. Lammering, U. Gabbert, M. Sinapius, T. Schuster, P. Wierach (Eds)(2018) Lamb-Wave Based Structural Health Monitoring in Polymer Composites, Springer International Publishing. [2] Paul-Dubois-Taine A, Amsallem D. An adaptive and efficient greedy procedure for the optimal training of parametric reduced-order models. International Journal for Numerical Methods in Engineering 2014.
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Gresil, Matthieu, Bin Lin, Yanfeng Shen et Victor Giurgiutiu. « Predictive Modeling of Space Structures for SHM With PWAS Transducers ». Dans ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/smasis2011-5190.

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This paper presents an investigation of predictive modeling of space structures for structural health monitoring (SHM) with piezoelectric wafer active sensors (PWAS) transducers. The development of a suitable SHM system for complex space structure is not trivial; creating a robust SHM capability requires at least: (a) flexible accommodation of numerous configurations; (b) detection of damage in complex multifunctional structures; (c) identification if mechanical interfaces are properly connected. To realize this, we propose a predictive modeling approach using both analytical tools and finite element method (FEM) to study the health status of the structure, the power and energy transduction between the structure and the PWAS. After a review of PWAS principles, the paper discusses the modeling and the power and energy transduction between structurally guided waves and PWAS. The use of guided wave (GW) and the capability of embedded PWAS to perform in situ nondestructive evaluation (NDE) are explored. FEM codes are used to simulate GW of 2D and 3D space structure using the commercials software ABAQUS. PWAS transducers placement at different location on a flat plate and on an isogrid panel was simulated. The signal scattered by a crack emerging from the hole is simulated. Predictive modeling of power and energy transduction is discussed using an analytical approach. This model of 2-D power and energy transduction of PWAS attached to structure allows examination of power and energy flow for a circular crested wave pattern. Wave propagation method for an infinite boundary plate, electromechanical energy transformation of PWAS and structure, and wave propagation energy spread out in 2-D plate are considered. The parametric study of PWAS size, impedance match gives the PWAS design guideline for PWAS sensing and power harvesting applications.
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Lu, Runye, et Yanfeng Shen. « Nonlinear Electro-Mechanical Impedance Spectroscopy for Comprehensive Monitoring of Carbon Fiber Reinforced Composite Laminates ». Dans ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-94882.

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Abstract This paper presents a Nonlinear Electromechanical Impedance Spectroscopy (NEMIS) methodology for the comprehensive monitoring of carbon fiber reinforced composite (CFRC) laminates. This method can obtain structural impedance spectra and capture nonlinear ultrasonic features for damage detection, combining the merits of the conventional EMIS and the nonlinear ultrasonic techniques. A comparative illustration between the conventional EMIS and NEMIS is presented. Various damage types and damage mechanisms of CFRC laminates are reviewed. Numerical investigation on a reduced-order 1-D Contact Acoustic Nonlinearity (CAN) model are conducted to demonstrate the chirp-induced nonlinear features. Furthermore. a finite element (FE) model is established to verify the feasibility of the NEMIS for damage detection. The macro-scale damage types are modeled by the changes of material properties, while the incipient damage like delamination is simulated by setting the contact interfacing condition between the laminate debonding areas. Correspondingly, the chirp-based impedance spectra are employed to detect the macro-scale damage via the deviation of resonance peaks, while the nonlinear features, such as higher harmonics and wave modulation are utilized to monitor the delamination. Two damage indices are developed to quantify the severity of both the macro and incipient damage. This paper finishes with conclusion and suggestions for future work.
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