Academic literature on the topic 'Disc signal intensity'
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Journal articles on the topic "Disc signal intensity"
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Abdollah, Vahid, Eric C. Parent, and Michele C. Battié. "Is the location of the signal intensity weighted centroid a reliable measurement of fluid displacement within the disc?" Biomedical Engineering / Biomedizinische Technik 63, no. 4 (July 26, 2018): 453–60. http://dx.doi.org/10.1515/bmt-2016-0178.
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Abstract Degenerated discs have shorter T2-relaxation time and lower MR signal. The location of the signal-intensity-weighted-centroid reflects the water distribution within a region-of-interest (ROI). This study compared the reliability of the location of the signal-intensity-weighted-centroid to mean signal intensity and area measurements. L4-L5 and L5-S1 discs were measured on 43 mid-sagittal T2-weighted 3T MRI images in adults with back pain. One rater analysed images twice and another once, blinded to measurements. Discs were semi-automatically segmented into a whole disc, nucleus, anterior and posterior annulus. The coordinates of the signal-intensity-weighted-centroid for all regions demonstrated excellent intraclass-correlation-coefficients for intra- (0.99–1.00) and inter-rater reliability (0.97–1.00). The standard error of measurement for the Y-coordinates of the signal-intensity-weighted-centroid for all ROIs were 0 at both levels and 0 to 2.7 mm for X-coordinates. The mean signal intensity and area for the whole disc and nucleus presented excellent intra-rater reliability with intraclass-correlation-coefficients from 0.93 to 1.00, and 0.92 to 1.00 for inter-rater reliability. The mean signal intensity and area had lower reliability for annulus ROIs, with intra-rater intraclass-correlation-coefficient from 0.5 to 0.76 and inter-rater from 0.33 to 0.58. The location of the signal-intensity-weighted-centroid is a reliable biomarker for investigating the effects of disc interventions.
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Milette, Pierre C., Suzanne Fontaine, Luigi Lepanto, Étienne Cardinal, and Guy Breton. "Differentiating Lumbar Disc Protrusions, Disc Bulges, and Discs With Normal Contour but Abnormal Signal Intensity." Spine 24, no. 1 (January 1999): 44–53. http://dx.doi.org/10.1097/00007632-199901010-00011.
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O’Neill, Conor. "Accuracy of MRI for Diagnosis of Discogenic Pain." Pain Physician 3;11, no. 5;3 (May 14, 2008): 311–26. http://dx.doi.org/10.36076/ppj.2008/11/311.
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Background: Previous studies have compared MRI parameters to the results from discography. However, none have evaluated the overall diagnostic performance of MRI, taking into account that many MRI characteristics may be correlated. Objective: Determine the accuracy of MRI for diagnosis of discogenic pain, taking into consideration the interdependence of MRI parameters. Study Design: An observational report. Setting: Sample of 143 patients, 92 male and 51 female in a spinal pain speciality center. Discography classification and scorings for MRI parameters were collected as outcome measures. Methods: MRI and discography data were collected from patients with chronic low back pain. Five MRI characteristics were defined: high intensity zone, nuclear signal, disc height, disc contour, and bone marrow intensity change. On discography, each disc was classified as either positive or negative. The accuracy of MRI was evaluated using receiver operating characteristic curves. Results: MRI parameters are correlated with each other and with discography findings, and these correlations affect the accuracy of MRI. Overall, nuclear signal alone is as accurate as any of the other MRI parameters, or combination of parameters, in the diagnosis of discogenic pain. While there is no difference in overall accuracy between nuclear signal and the other MRI parameters, these parameters do influence test performance when there is a moderate loss of nuclear signal . Moderate loss of nuclear signal and disc bulge has the best combination of sensitivity (79.8%) and specificity (79.3%). Adding moderate loss of disc height improves specificity (82.0%) slightly, and decreases sensitivity (73.6%) slightly, while incorporating high intensity zone grade II further improves specificity (92.6%) and decreases sensitivity (54.7%). High intensity zone grade I and bone marrow intensity change have minimal influence, even when there is moderate loss of nuclear signal. Conclusions: MRI parameters are correlated with each other and with discography findings, influencing the diagnostic performance of MRI. Combining MRI parameters improves the diagnostic performance of MRI, but only in the presence of moderate loss of nuclear signal. When there is either normal nuclear signal or severe loss of nuclear signal the other MRI parameters have no influence on test performance. The practical implication for physicians that use discography is that the most important single MRI parameter to consider is nuclear signal. If nuclear signal is normal the disc is very likely to be negative on discography, while if there is severe loss of nuclear signal it is very likely to be positive. Discography will be most useful in discs with moderate loss of nuclear signal, particularly if there are no other MRI abnormalities present. Key words: Discography, MRI, ROC curve, chronic back pain, neural signal, disc contour, high intensity zone
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Ma, Chao, Ran Wang, Dingliang Zhao, Naikun Wang, Ying Han, Shichong Wang, Tianyun Gao, Bin Wang, and Lijuan Lu. "Efficacy of Platelet-Rich Plasma Containing Xenogenic Adipose Tissue-Derived Stromal Cells on Restoring Intervertebral Disc Degeneration: A Preclinical Study in a Rabbit Model." Pain Research and Management 2019 (April 16, 2019): 1–7. http://dx.doi.org/10.1155/2019/6372356.
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Objective. Platelet-rich plasma (PRP) containing multiple growth factors is a promising strategy for disc degeneration. Thus, this study hypothesizes that the combination of PRP and adipose tissue-derived stromal cells (ADSCs) may repair degenerative disc more effectively than using each one of them alone. Methods. The model of early intervertebral disc degeneration was induced by annular puncture in the New Zealand rabbit. Autologous PRP was extracted from fresh arterial blood by using two centrifugation techniques. ADSC was offered by the Center for Clinic Stem Cell Research. Four weeks after the first experiment, PRP or ADSCs or a combination of PRP and ADSCs was injected into the punctured intervertebral disc. Four weeks later, disc height and signal intensity on T2-weighted magnetic resonance imaging (MRI) were assessed. Results. One month after puncture, we detected relatively narrow discs and lower signal intensity in MRI T2-weighted images. At four weeks after injection, the PRP-ADSC group statistically significantly restored discs, compared with PRP, ADSCs, or negative control group. Conclusions. The combination of PRP and ADSCs shows an effective potential to restore degenerated intervertebral discs in the rabbit.
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Şener, Sevgi, and Faruk Akgünlü. "Correlation of Different MRI Characteristics of Anterior Disc Displacement With Reduction and Without Reduction." Journal of Contemporary Dental Practice 6, no. 1 (2005): 26–36. http://dx.doi.org/10.5005/jcdp-6-1-26.
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Abstract The aim of this study was to evaluate the correlations between magnetic resonance imaging (MRI) findings in anterior displacement with reduction (ADDR) and anterior displacement without reduction (ADDWR). Two hundred patients with temporomandibular disorder (TMD) symptoms were examined clinically by a clinician experienced with this disorder. There were 130 joints with ADDR and 45 joints with ADDWR; 88 patients were identified according to the clinical and MRI diagnoses of both observers. The MRI characteristics such as position, signal intensity, morphology of disc, degenerative changes, effusion, scar tissue, avascular necrosis, and condylar hypermobility were evaluated in the individual with ADDR and ADDWR. The Chi-square test was used to determine the correlation between MRI characteristics in the ADDR and the ADDWR. There were significant relationships between degenerative changes and increased signal intensity, degenerative changes and side-way displacement, effusion and the deformation of the disc, effusion and subluxation, increased signal intensity and subluxation, elongation deformation and increased signal intensity, and elongation deformation and side-way displacement in ADDR. There were significant relationships between degenerative changes and effusion, degenerative changes and decreased signal intensity, scar tissue and avascular necrosis, deformation of disc and increased signal intensity, as well as deformation of disc and decreased signal intensity in ADDWR. These MRI findings also correlated with the clinical findings, however, this correlation appears to be a synergistic pattern rather than a set of clear-cut relationships. The correlations between these MRIs and different clinical findings such as pain and dysfunction also must be evaluated. Existing correlations must be considered in the diagnosis and treatment planning of TMD, and signs and symptoms of TMD should be monitored after treatment. Citation Şener S, Akgünlü F. Correlation of Different MRI Characteristics of Anterior Disc Displacement With Reduction and Without Reduction. J Contemp Dent Pract 2005 February;(6)1:026-036.
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Haughton, Victor. "Point of View: Differentiating Lumbar Disc Protrusions, Disc Bulges, and Discs With Normal Contour but Abnormal Signal Intensity." Spine 24, no. 1 (January 1999): 53. http://dx.doi.org/10.1097/00007632-199901010-00012.
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Park, Chong Oon. "Diurnal variation in lumbar MRI: Correlation between signal intensity, disc height, and disc bulge." Yonsei Medical Journal 38, no. 1 (1997): 8. http://dx.doi.org/10.3349/ymj.1997.38.1.8.
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Urakado, Misao, Masakuni Naruo, Eiichi Koyanagi, Toshimitsu Nogami, Yuuji Taoka, Hiroshi Ogata, Hiroshi Yoshimi, and Ryouki Nojiri. "Evaluation of Lumbar Disc Degeneration in Adults Using Magnetic Resonance Imaging. Correlation between Peridiscal Signal Intensity and Nuclear Signal Intensity in 1773 Discs." Orthopedics & Traumatology 43, no. 4 (1994): 1300–1305. http://dx.doi.org/10.5035/nishiseisai.43.1300.
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Wang, Lin-Feng, Ying-Ze Zhang, Yong Shen, Yan-Ling Su, Jia-Xin Xu, Wen-Yuan Ding, and Ying-Hua Zhang. "Using the T2-weighted magnetic resonance imaging signal intensity ratio and clinical manifestations to assess the prognosis of patients with cervical ossification of the posterior longitudinal ligament." Journal of Neurosurgery: Spine 13, no. 3 (September 2010): 319–23. http://dx.doi.org/10.3171/2010.3.spine09887.
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ObjectThe aim of this study was to investigate the clinical significance of both the signal intensity ratio obtained from MR imaging and clinical manifestations on the prognosis of patients with cervical ossification of the posterior longitudinal ligament.MethodsThe authors retrospectively reviewed the records of 58 patients with cervical ossification of the posterior longitudinal ligament who underwent cervical laminoplasty from February 1999 to July 2007. Magnetic resonance imaging (1.5-T) was performed in all patients before surgery. Sagittal T2-weighted images of the cervical spinal cord compressed by the ossified posterior longitudinal ligament showed increased intramedullary signal intensity, whereas the sagittal images obtained at the C7–T1 disc levels were of normal intensity. The signal intensity ratio between regions of intramedullary increased signal intensity and the normal C7–T1 disc level was calculated based on the signal intensity values generated from the MR imaging workstation. Patients were divided into 3 groups according to their signal intensity ratio (high, intermediate, and low signal intensity groups).ResultsThere were significant differences between the 3 groups regarding recovery rate (p < 0.001), age (p = 0.022), duration of disease (p = 0.001), Babinski sign (p < 0.001), ankle clonus (p < 0.001), and both pre- and postoperative Japanese Orthopaedic Association score (p < 0.001). There was no significant difference in sex among the 3 groups (p = 0.391).ConclusionsPatients with low signal intensity ratios that changed on T2-weighted imaging experienced a good surgical outcome. Low increased signal intensity might reflect mild neuropathological alteration in the spinal cord and greater recuperative potential. An increased signal intensity ratio with positive pyramidal signs indicates less recuperative potential of the spinal cord and a poor surgical outcome.
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Hoffman, Haydn, Aaron W. Choi, Victor Chang, Jon Kimball, Alan S. Verkman, Rubeen Virani, Brian Kim, Tianyi Niu, and Daniel C. Lu. "Aquaporin-1 Expression in Herniated Human Lumbar Intervertebral Discs." Global Spine Journal 7, no. 2 (April 2017): 133–40. http://dx.doi.org/10.1177/2192568217694007.
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Study Design: Case series. Objective: Intervertebral disc (IVD) degeneration is the cause of spondylosis. The pathogenesis is poorly understood, but disc dehydration often plays a role. In this study, we aim to identify and quantify aquaporin-1 (AQP1) in ex vivo human degenerated IVDs obtained intraoperatively and to investigate the relationship between AQP1 levels and magnetic resonance imaging (MRI) T2 intensity of the disc. Methods: Ex vivo samples of nucleus pulposus (NP) tissue from lumbar IVDs were obtained from 18 consecutive patients who underwent surgery for disc herniation at L4/5 and L5/S1 level. Immunohistochemistry was performed to determine the presence of AQP1 expression, and this was quantified by Western blot analysis. AQP1 expression was compared to preoperative IVD signal intensity on T2-weighted MRI. Results: NP tissue was obtained from 18 patients (9 for L4/5 level and 9 for L5/S1 level). AQP1 expression was detected in all samples by Western blot and immunohistochemistry. AQP1 expression had a linear correlation with the preoperative IVD signal intensity on T2-weighted MRI at L4/5 level ( R2 = 0.90) and at L5/S1 level ( R2 = 0.92). AQP1 expression was 52.2 ± 59.0 at L5/S1 level and 15.9 ± 20.6 at L4/5 ( P = .10). Conclusions: Our results show that AQP1 can be detected in IVD obtained from live human subjects. Increased AQP1 expression is associated with greater disc hydration as measured by signal intensity on T2-weighted MRI. AQP1 may have a role in the dehydration associated with disc degeneration.
Dissertations / Theses on the topic "Disc signal intensity"
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Warmling, Luiza Verônica. "Avaliação por meio da ressonância magnética do sinal do tecido retrodiscal associado à anotomia de eminência articular do osso temporal na presença de derrame articular e deslocamento do disco com e sem redução em pacientes sintomáticos." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/23/23139/tde-04072013-162640/.
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Este estudo avaliou por meio da Ressonância Magnética a intensidade de sinal do tecido retrodiscal associando a anatomia da eminência articular, derrame articular e deslocamento do disco com e sem redução. Para isto, foram analisadas imagens por RM de 48 ATM de 24 indivíduos sintomáticos, sendo 19 (79,2%) do gênero feminino e 5 (20,8%) do gênero masculino. Considerando o posicionamento sagital, cerca de 5 (10,4%) das articulações eram normais, 23 (47,9%) das articulações eram DDCR e 20 (41,7%) eram DDSR. Para a forma da eminência articular, cerca de 15 (31,3%) das articulações foram classificadas como tendo formato de caixa, 12 (25,0%) foram classificadas como sigmoide, 10 (20,8%) como aplainada e 11 (22,9%) das articulações foram classificadas como deformada. A maioria das articulações apresentaram derrame cerca de 32 (66,7%). Das articulações com DDSR, 16 (51,6%) apresentaram derrame e as com DDCR 15 (48,4%). As articulações com DDCR apresentaram 9 (39,15) em forma de caixa, 6 (26,1%) como sigmóide, 3 (13,0%) estavam aplainada e 5 (21,7%) deformadas; as ATM com DDSR apresentaram 5 (25,5%) como caixa, 4 (20,0%) como sigmóide, 6 (30,0%) aplainadas e 5 (25,5%) deformadas. A forma da eminência articular não está relacionada ao posicionamento sagital (p=0,520). O posicionamento sagital do disco não está relacionado à presença de derrame (p=0,281). A intensidade de sinal do TR foi estatisticamente menor no posicionamento sagital DDCR, quando comparado ao posicionamento sagital DDSR (p=0,016). Houve uma tendência da intensidade do sinal do tecido retrodiscal ser maior nas articulações com derrame quando comparado às sem derrame (p=0,065). Não houve relação entre posicionamento sagital do disco e derrame. E por fim, o presente estudo não conseguiu estabelecer uma relação entre o sinal do tecido retrodiscal e eminência articular (p=0,159).This study evaluated MR signal intensity of retrodiscal tissue associated with articular eminence morphology, joint effusion status, and disc displacement with and without reduction (DDwR and DDwoR, respectively). Forty-eight TMJ MR images of 24 symptomatic subjects (19 females and 5 males) were analyzed. For the sagittal position, 5 (10.4%) joints were normal, 23 (47.9%) showed DDwR and 20 (41.7%) DDwoR. Regarding articular eminence morphology, 15 (31.3%) joints were classified as box-shaped, 12 (25.0%) as sigmoid, 10 (20.8%) flattened and 11 (22.9%) deformed. The majority of TMJs (32 or 66.7%) showed effusion. Sixteen (51.6%) of the TMJs with DDwoR had effusion versus 15 (48.4%) of those with DDDwR. Of TMJs with DDwR, 9 (39.1%) were box-shaped, 6 (26.1%) sigmoid, 3 (13.0%) flattened and 5 (21.7%) deformed. Among joints with DDwoR, 5 (25.5%) were boxshaped, 4 (20.0%) sigmoid, 6 (30.0%) flattened and 5 (25.5%) deformed. As a conclusion, articular eminence shape was not related to sagittal position of the disk (p = 0.520). Sagittal position of the disk was not related to presence of effusion (p = 0.281). Signal intensity of retrodiscal tissue (RT) was statistically lower in the DDwR sagittal position than in DDwoR cases (p = 0.016). There was a tendency for higher RT signal intensity in joints with effusion versus those without effusion (p = 0.065). No relationship between sagittal position of the disc and effusion was observed. No relationship between signal intensity of retrodiscal tissue and shape of articular eminence was identified (p = 0.159).
Conference papers on the topic "Disc signal intensity"
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Cetiner, Halit, and Bayram Cetisli. "Optical disc detection based on intensity and feature in the retinal images." In 2015 23th Signal Processing and Communications Applications Conference (SIU). IEEE, 2015. http://dx.doi.org/10.1109/siu.2015.7129795.
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Wang, Mark M., Frederick B. McCormick, and Sadik C. Esener. "2D and 3D Equalizers for Page-Oriented Optical Memories." In Optics in Computing. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/oc.1997.owd.4.
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In this study we investigate the use of 2D and 3D equalizers to suppress intersymbol interference (ISI) in 2D parallel channels. The techniques demonstrated here are best suited for parallel implementation and can be used for any page-oriented readout application including increasing the data density achievable in volume optical memories or increasing the number of links achievable in free-space optical interconnects. Page-oriented optical memories are currently being investigated for their potential as high data-rate, high capacity storage devices,1-3 however the cost-effectiveness of such devices is limited by their requirements for high resolution in the optical system and severe alignment tolerances on the 2D detector array. Various techniques have been used in an attempt to reduce the amount of ISI generated by optical aberrations and misalignment including the use of guard bands around each bit and also reduced fill-factor detectors,2,3 however such techniques have the undesirable result of also reducing the signal intensity of each bit. An alternative approach is to remove the crosstalk electronically after detection. Serial equalizers have been used for years in communications and storage channels as a method of reducing ISI in a temporal bit stream.4 Limited 2D equalizers have also been demonstrated to reduce inter-track interference in high density optical disc recordings with multiple-beam readout heads.5-7 The use of partial-response maximum-likelihood (PRML) detection has been demonstrated to reduce the effects of crosstalk in page-oriented memories, however the complexity of PRML detectors increases rapidly as the number of spatial dimensions and the number of possible states increases.8 In this paper we propose the design of 2D and 3D equalizers suitable for page-access optical memories and investigate the performance of both linear and decision feedback implementations.
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Okamoto, Hiromi, Shun Hashiyada, Yoshio Nishiyama, and Tetsuya Narushima. "Imaging Chiral Plasmons." In JSAP-OSA Joint Symposia. Washington, D.C.: Optica Publishing Group, 2017. http://dx.doi.org/10.1364/jsap.2017.5a_a410_1.
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Chirality is a broad concept that characterizes structures of systems in almost all hierarchy of materials in natural sciences. Molecular chirality is sometimes essential in biological functions. Also in nanomaterials sciences, chirality plays a key role. It is of fundamental importance to investigate internal structures (geometrical distributions) of chiral optical responses in nanomaterials, to design chiral features of the materials and their functions. We developed near-field optical activity (typically circular dichroism, CD) imaging systems that allow us to visualize local structures of optical activity in nanomaterials, and observed near-field CD images of two-dimensional gold nanostructures fabricated with electron beam lithography lift-off technique. We found that the amplitudes of local CD signals were as large as 100 times the macroscopic CD signals of the same samples, for two-dimensional chiral gold nanostructures [1]. Even highly symmetric achiral structures that never give CD signals macroscopically gave locally very strong CD signals (a typical example for a rectangular nanostructure is shown in Figure 1) [2,3]. In this case, average of the signal over the nanostructure yielded roughly null CD intensity. While achiral nanostructures show in general local CD activities as mentioned above, circularly symmetric (two-dimensionally isotropic) nanostructures, such as circular disks, never give CD signals at any local positions. However, when the circular disk is illuminated with linearly polarized light, the circular symmetry is broken, and thus the system potentially yields locally chiral optical (i.e., circularly polarized) fields. To demonstrate that, we extended the near-field CD microscope, and enabled irradiation of well- defined linearly polarized near-field on the sample and detection of scattered-field ellipticity and polarization azimuth angle. We found for circular gold disks that the scattered field was actually elliptically polarized. The ellipticity and the azimuth angle of the scattered field depended on the incident polarization angle and relative position on the disk.
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Geis, T., A. Wiebelt, S. Kim, and S. Wittig. "Ingress Determination by Means of Laser Light Scattering Inside a Rotor-Stator System." In ASME 1999 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/99-gt-247.
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A new method based on laser light scattering was developed to detect a radial inflow of gas inside a rotating-disk system. Ambient air was seeded with small particles that followed the flow. Once entering the wheel space between rotor and stator, these particles crossed a laserbeam emitted by an At+-Laser. The scattered light was detected by a photomultiplier whose electrical output signal was finally processed in a data acquisition system. The signal intensity thereby indicated the strength of ingress. The measuring technique was adapted to a shrouded rotor-stator system in a quiescent environment and an experimental investigation was conducted to determine the minimum cooling flow rate necessary to just prevent ingress (Cw,min) for several seal clearance ratios and two different rotor disk geometries. The results were correlated to the disk rotational Reynolds number and compared with data yielded by applying a pressure criterion. With the rotating disk being 0.5m in diameter and spinning at max. 10000rpm, rotational Reynolds numbers up to 3.8×106 were achieved. The results show an expected behaviour for the seal clearance variation and an unexpected behaviour for the two disk geometries. Compared to the new technique, the pressure criterion underestimates the minimum purge flow. Additional experiments were conducted for a single seal configuration to demonstrate the new method’s capability to acquire the sealing effectiveness. The results are intriguing but also show that further investigations must be conducted to establish this new technique.
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Sebastian, Ron, Benjamin Kelkel, Martin Gurka, Tobias Traub, and Johannes L’huillier. "Laser Induced Lamb Wave Generation for Structural Health Monitoring of Carbon Fiber Reinforced Polymers." In ASME 2015 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/smasis2015-8815.
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In this paper we present an innovative concept for the excitation of guided acoustic waves (lamb waves) in carbon fiber reinforced polymers (CFRP). The idea is to add this external signal generation to a passive structural health monitoring system (SHM), using the now active system for nondestructive testing (NDT). The whole system consists of piezoelectric sensors, embedded in the polymer matrix of the monitored component, the external laser in combination with a scanning device for spatial resolved generation of acoustic waves and a signal processing unit for data analysis. Using laser excitation for lamb wave generation helps to overcome several dis-advantages compared to the use of piezoelectric transducers only: The flexibility in repositioning of the excitation area allows for easy compensation of the strong signal attenuation of CFRP with a minimum number of piezoelectric transducers. The variation of laser wavelength in the range of 1024 to 3500 nm in combination with variation in intensity allows for a selective coupling of the acoustic waves either into the matrix or in the C fibers. Using piezoelectric transducers for detection only, omits the need for a large number of high-voltage amplifiers for signal generation. In this contribution we present first results of a systematic investigation of the effective generation of lamb waves in CFRP. In addition to the variation of the wavelength of the laser, the intensity was varied too. A potentially damaging influence of the laser radiation on the CFRP material was investigated.
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Korobko, Evguenia V., Valery A. Mansurov, Elena B. Kaberdina, and Vyacheslav A. Bilyk. "Some Peculiarities in Behavior of Electrosensitive Fluids Under Electric Field." In ASME 8th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2006. http://dx.doi.org/10.1115/esda2006-95152.
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Rheological behavior of electrorheological fluid (ERF) under electric field is investigated experimentally and structural strengthening and viscoplastic characteristics are evaluated at different intensities of electric field and various concentrations of solid phase in ERF under its deformation in the system of disk parallel surfaces. An increase of the first difference of normal stresses is found at the increase of intensity of electric field applied, and also its change in time. At that the change of the sign of normal stresses takes place depending on magnitude of electric field and deformation.
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Nakamura, Yuki, and Toshihiko Shiraishi. "A Study of a Cell Mechanosensing System Under Mechanical Vibration Considering its Modes of Vibration and Calcium Ion Response." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71363.
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It was reported that osteoblastic cells respond to mechanical vibration and generate the bone mass with a peak at a specific frequency like a resonance curve [1]. There seems to be an analogy between its cell response and the resonance of a cell as a mechanical system. This paper describes a novel method to measure the cellular modes of vibration of a cell and its calcium ion response under mechanical vibration, and the evaluation of the obtained results to clarify the mechanism of the cell mechanosensing. Nuclei and calcium ion in osteoblastic cells were visualized with fluorescent labelling. Mechanical vibration was applied to cells in a dish in the horizontal direction under a confocal laser scanning microscope by an exciter. Since the fluorescent intensity was very weak due to high frame rate to capture moving cells under Mechanical vibration, we used a high-speed and high-sensitive camera adjusting various conditions such as exposure time. We realized the spatial resolution of approximately 2 μm in the captured micrographs even under mechanical vibration using the experimental setup. As a result, the modes of vibration of nuclei was not obtained in this resolution. We found that the intracellular calcium ion concentration began to increase in a few seconds after mechanical vibration was applied. This experimental result indicates that applying mechanical vibration to cells can produce calcium signals as a second messenger by causing the entry of the ion.
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Supraptomo, Rth. "A Case Report on Regional Anaesthesia in Pregnant Women with Severe Pre-Eclampsia, Partial Hellp Syndrome, Fetal Distress, and Type II Diabetes Mellitus." In The 7th International Conference on Public Health 2020. Masters Program in Public Health, Universitas Sebelas Maret, 2020. http://dx.doi.org/10.26911/the7thicph.05.29.
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ABSTRACT Background: Maternal mortality in Indonesia is caused by multifactors that are both direct and indirect factors. Complications during pregnancy and after delivery, including preeclampsia is the direct cause of 90% of maternal deaths. This case report aimed to describe the anaesthesia management on the incidence of severe preeclampsia to prevent the complications. Subjects and Method: We reported a 33-year-old G3P2A0 woman with 33 weeks of gestational age, diagnosed with severe pre-eclampsia partial HELLP syndrome, fetal dis-tress, type II diabetes mellitus pro SCTP emergency with physical status ASA II. Regional anaesthesia with sub-arachnoid block was performed by using Lidodex 75 mg and fentanyl 25 mcg intrathecally. Results: From the operation process, a baby boy with birth weight 2.900 gram and APGAR Score 7-8-9 was born. Two-hour post operation examination on patient showed compos mentis (consciousness), blood pressure 121/ 80 mmHg, heart rate 64 bpm, respiration rate 20 breath per minute, blood oxygen saturation levels (SpO2) 99% with 3 L/min nasal cannula. Patient was administered to HCU post operation to be monitored vital sign and signs of impending eclampsia. Post-operative refeeding was performed after bowel sound was positive. Conclusion: Selection of appropriate anaesthetic management in severe preeclampsia cases can prevent complications. Keywords: severe preeclampsia, sectio caesaria, regional anesthesia, subarachnoid block Correspondence: R. Th. Supraptomo. Department of Anaesthesiology and Intensive Therapy Dr. Moewardi Hospital. Jl Kolonel Sutarto 132 Jebres, Surakarta, Central Java, 57126. Email: ekasatrio-@gmail.com. Mobile: +6281329025599. DOI: https://doi.org/10.26911/the7thicph.05.29
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Oh, Jaekyoon, Yungpil Yoo, Samsun Seung, and Ho-Young Kwak. "Laser-Induced Bubble Formation on a Micro Gold Particle Levitated Under Ultrasound." In ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ht2016-1006.
Full textAbstract:
It is well known that a high-power laser could breakdown liquid [1, 2]. Laser-induced breakdown of liquids is characterized by fast plasma formation after evaporation of liquid and subsequent vapor expansion accompanied by shock wave emission [2]. The bubble wall velocity after the shock departure has been found to be sufficiently high to produce emission of light at the collapse point [3]. Recently, bubble formation on the surface of gold nanoparticles irradiated by a high-power laser in water [4, 5] has been studied for medical applications such as cancer diagnosis and possible therapy [5]. However, it is very hard to perform these experiments and to obtain good data from the bubble formation on the surface of laser-irradiated nano-particles because the nanoparticles dispersed in liquid cannot be controlled properly. In this study, laser-induced bubble formation on a micro gold particle levitated at the center of a spherical flask under ultrasound was investigated experimentally. The obtained results are compared with the results for laser cavitation without the gold particle, i.e., typical laser-induced cavitation. Figure 1 shows a schematic of the experimental setup used to investigate the laser-induced bubble formation on a micro gold particle. Two disk-type lead zirconate titanate (PZT) transducers (Channel Industries Inc.; 15 mm in diameter and 5.0 mm in thickness) attached to the side of the wall of the cell produced a velocity stagnation point near the center of the flask. The driving frequency of the PZT transducers was approximately 27.0 kHz which was close to the resonance frequency of the LRC circuit (Its capacitor unis is PZT.) and the acoustic resonance frequency of the water-filled flask. A drop of water containing gold particles with an average diameter of 10 μm are dispersed was injected into a 100-ml pyrex spherical flask filled with degassed water. When the body force of a gold particle in liquid is slightly lower than the Bjerknes force [6] induced by ultrasound, the particle will stay near the pressure antinode, i.e., the center of the flask. A Q-switched Nd:Yag laser delivered a single pulse of 0.5 ns in width with an energy of 7.5 mJ at a wavelength of 1064 nm to the gold particle or liquid at the center of the cell. The laser light was focused at the center of the flask using a lens with an effective focal length of 36.3 mm. Bubble formation and subsequent growth and collapse were visuallized by a high-speed camera (V2511, Phantom, USA) with 0.45 Mfps (million frames per second). The time-dependent radius was also obtained by the light scattering method. The scattering angle chosen was 80 degree where one-to-one relationship exists between the scattered intensity and the bubble radius [7]. The scattered intensity from a bubble illuminated by a 5-mW He-Ne laser was received by a photomultiplier tube (PMT: Hamamatsu, R2027) and was recorded in an oscilloscope. The scattering data were calibrated using the maximum radius for different bubble, which was obtained by high-speed camera. The shock strength during the expansion stage of bubbles was measured by a calibrated needle hydrophone (HPM1, Precision Acoustics, UK) at various distances from the center of the cell for different bubbles. The hydrophone can measure acoustic signals ranging from 1 kPa to 20 MPa. The hydrophone was attached to a three-dimensional micro stage so that fine control of the positioning of the hydrophone was possible.