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Sample records for adenosine dual source

  1. Adenosine-stress dynamic myocardial perfusion imaging using 128-slice dual-source CT: optimization of the CT protocol to reduce the radiation dose.

    Science.gov (United States)

    Kim, Sung Mok; Kim, Yoo Na; Choe, Yeon Hyeon

    2013-04-01

    The aim of this study was to compare the radiation dose and image quality of different adenosine-stress dynamic myocardial perfusion CT protocols using a 128-slice dual-source computed tomography (DSCT) scanner. We included 330 consecutive patients with suspected coronary artery disease. Protocols employed the following dynamic scan parameters: protocol I, a 30-s scan with a fixed tube current (FTC, n = 172); protocol II, a 30-s scan using an automatic tube current modulation (ATCM) technique (n = 108); protocol III, a 14-s scan using an ATCM (n = 50). To determine the scan interval for protocol III, we analyzed time-attenuation curves of 26 patients with myocardial perfusion who had been scanned using protocol I or II. The maximum attenuation difference between normal and abnormal myocardium occurred at 18.0 s to 30.3 s after initiation of contrast injection. Myocardial perfusion images of FTC and ATCM were of diagnostic image quality based on visual analysis. The mean radiation dose associated with protocols I, II, and III was 12.1 ± 1.6 mSv, 7.7 ± 2.5 mSv, and 3.8 ± 1.3 mSv, respectively (p < 0.01). Use of a dose-modulation technique and a 14-s scan duration for adenosine-stress CT enables significant dose reduction while maintaining diagnostic image quality.

  2. Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results

    Energy Technology Data Exchange (ETDEWEB)

    Weininger, Markus [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Department of Medicine, Division of Cardiology, Medical University of South Carolina, Charleston, SC (United States); Ramachandra, Ashok [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Fink, Christian [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Rowe, Garrett W.; Costello, Philip [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Henzler, Thomas [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany)

    2012-12-15

    Purpose: Recent innovations in CT enable the evolution from mere morphologic imaging to dynamic and functional testing. We describe our initial experience performing myocardial stress perfusion CT in a clinical population with acute chest pain. Methods and materials: Myocardial stress perfusion CT was performed on twenty consecutive patients (15 men, 5 women; mean age 65 ± 8 years) who presented with acute chest pain and were clinically referred for stress/rest SPECT and cardiac MRI. Prior to CT each patient was randomly assigned either to Group A or to Group B in a consecutive order (10 patients per group). Group A underwent adenosine-stress dynamic real-time myocardial perfusion CT using a novel “shuttle” mode on a 2nd generation dual-source CT. Group B underwent adenosine-stress first-pass dual-energy myocardial perfusion CT using the same CT scanner in dual-energy mode. Two experienced observers visually analyzed all CT perfusion studies. CT findings were compared with MRI and SPECT. Results: In Group A 149/170 myocardial segments (88%) could be evaluated. Real-time perfusion CT (versus SPECT) had 86% (84%) sensitivity, 98% (92%) specificity, 94% (88%) positive predictive value, and 96% (92%) negative predictive value in comparison with perfusion MRI for the detection of myocardial perfusion defects. In Group B all myocardial segments were available for analysis. Compared with MRI, dual-energy myocardial perfusion CT (versus SPECT) had 93% (94%) sensitivity, 99% (98%) specificity, 92% (88%) positive predictive value, and 96% (94%) negative predictive value for detecting hypoperfused myocardial segments. Conclusion: Our results suggest the clinical feasibility of myocardial perfusion CT imaging in patients with acute chest pain. Compared to MRI and SPECT both, dynamic real-time perfusion CT and first-pass dual-energy perfusion CT showed good agreement for the detection of myocardial perfusion defects.

  3. Value of the adenosine test for diagnosis of dual AV nodal physiology in patients with AV nodal reentrant tachycardia

    Institute of Scientific and Technical Information of China (English)

    周斌全; 胡申江; 鲁端; 王建安

    2002-01-01

    Objectives: This study was aimed at assessing the value of the adenosine test for noninvasive diagnosis of dual AV nodal physiology(DAVNP) in patients with AV nodal reentrant tachycardia (AVNRT). Methods: 53 patients with paroxysmal supraventricular tachycardia (PSVT) were given incremental doses of adenosine intravenously during sinus rhythm before electrophysiological study. The adenosine test was repeated on a subset of 18 patients with AVNRT after radiofrequency catheter ablation. Results: Sudden increments of PR interval of more than 60 msec between two consecutive beats were observed in 26(83.9%) of 31 patients with typical AVNRT and 2 (9.1%) of 22 patients with AVRT and AT (P<0.01). The maximal PR increment between 2 consecutive beats in the AVNRT group(105±45ms) was significantly greater than that in the AVRT and AT group (20±13ms) (P<0.01).In postablation adenosine test, DAVNP was eliminated in all 8 patients who underwent slow pathway abolition that EPS showed the slow pathway disappeared and 4 of 10 patients who underwent slow pathway modification that EPS showed the slow pathway persisted. Six of 10 patients who exhibited persistent duality showed a marked reduction in the number of beats conducted in the slow pathway after adenosine injection(P<0.01).Conclusions: Administration of adenosine during sinus rhythm may be a useful bedside test for diagnosis of DAVNP in high percentage of patients with typical AVNRT and additionally for evaluating the effects of radiofrequency ablation.

  4. Value of the adenosine test for diagnosis of dual AV nodal physiology in patients with AV nodal reentrant tachycardia

    Institute of Scientific and Technical Information of China (English)

    周斌全; 胡申江; 等

    2002-01-01

    Objectives:This study was aimed at assessing the value of the adenosine test for noninvasive diagnosis of dual AV nodal physiology(DAVNP) in patients with AV nodal reentrant tachycardia(VANRT).Methods:53 patients with paroxysmal supraventricular tachycardia(PSVT) were given incremental doses of adenosine intravenously during sinus rhythm before electrophysiological study.The adenosine test was repeated on a subset of 18 patients with AVNRT after radiofrequency catheter ablation.Results:Sudden increments of PR interval of more than 60 msec between two consecutive beats were observed in 26(83.9%) of 31 patients with typical AVNRT and 2(9.1%) of 22 patients with AVRT and AT(P<0.01),The maximal PR increment between 2 consecutive beats in the AVNRT group(105±45ms) was significantly greater than that in the AVRT and AT group[(20±13ms) (P<0.01),In postablation adenosine test,DAVNP was eliminated in all 8 patients who underwent slow pathway abolition that EPS showed the slow pathway disappeared and 4 of 10 patients who underwent slow pathway modification that EPS showed the slow pathway disappeared and 4 of 10 patients who underwent slow pathway modification that EPS whosed the slow pathway persisted.Six of 10 patients whw exhibited persistent duality showed a marked reduction in the number of beats conducted in the slow pathway after adenosine injection(P<0.01),COnclusions:Administration of adenosine during sinus rhythm may be a useful bedside test for diagnosis of DAVNP in high percentage of patients with typical AVNRT and additionally for evaluating the effects of radiofrequency ablation.

  5. Exploiting dual otoacoustic emission sources

    Science.gov (United States)

    Abdala, Carolina; Kalluri, Radha

    2015-12-01

    Two distinct processes generate otoacoustic emissions (OAEs). Reflection-source emissions, here recorded as stimulus frequency OAEs, are optimally informative at low sound levels and are more sensitive to slight hearing loss; they have been linked to cochlear amplifier gain and tuning. Distortion-source emissions are strongest at moderate-high sound levels and persist despite mild hearing loss; they likely originate in the nonlinear process of hair cell transduction. In this preliminary study, we exploit the unique features of each by generating a combined reflection-distortion OAE profile in normal hearing and hearing-impaired ears. Distortion-product (DP) and stimulus-frequency (SF) OAEs were recorded over a broad range of stimulus levels and frequencies. Individual I/O and transfer functions were generated for both emission types in each ear, and OAE peak strength, compression threshold, and rate of compression were calculated. These combined SFOAE and DPOAE features in normal and hearing-impaired ears may provide a potentially informative and novel index of hearing loss. This is an initial step toward utilizing OAE source in characterizing cochlear function and dysfunction.

  6. Exploiting Dual Otoacoustic Emission Sources

    Science.gov (United States)

    Abdala, Carolina; Kalluri, Radha

    2016-01-01

    Two distinct processes generate otoacoustic emissions (OAEs). Reflection-source emissions, here recorded as stimulus frequency OAEs, are optimally informative at low sound levels and are more sensitive to slight hearing loss; they have been linked to cochlear amplifier gain and tuning. Distortion-source emissions are strongest at moderate-high sound levels and persist despite mild hearing loss; they likely originate in the nonlinear process of hair cell transduction. In this preliminary study, we exploit the unique features of each by generating a combined reflection-distortion OAE profile in normal hearing and hearing-impaired ears. Distortion-product (DP) and stimulus-frequency (SF) OAEs were recorded over a broad range of stimulus levels and frequencies. Individual I/O and transfer functions were generated for both emission types in each ear, and OAE peak strength, compression threshold, and rate of compression were calculated. These combined SFOAE and DPOAE features in normal and hearing-impaired ears may provide a potentially informative and novel index of hearing loss. This is an initial step toward utilizing OAE source in characterizing cochlear function and dysfunction. PMID:27695142

  7. Dual hairpin-like molecular beacon based on coralyne-adenosine interaction for sensing melamine in dairy products.

    Science.gov (United States)

    Wang, Guangfeng; Zhu, Yanhong; Chen, Ling; Zhang, Xiaojun

    2014-11-01

    This study presents a novel dual hairpin-like molecular beacon (MB) for the selective and sensitive detection of melamine (MA) based on the conjugation of MA and thymine. In this protocol, the coordination between coralyne and adenosine (A) leaded a dual hairpin-like MB and the fluorophore-quencher pair is close proximity resulting in the fluorescence quenching. With the addition of MA, it conjugated with thymine in the loop part of dual hairpin-like MB by triple H-bonds, triggering the dissociation of the dual hairpin-like MB. The resulting spatial separation of the fluorophore from quencher induced the enhancement in fluorescence emission. Under the optimized conditions, the sensor exhibited a wide linear range of 8×10(-9)-1.6×10(-5) M (R(2)=0.9969) towards MA, with a low detection limit of 5 nM, approximately 4000 times lower than the Drug Administration and the US Food estimated MA safety limit. The real milk samples were also investigated with a satisfying result.

  8. Synthesis and pharmacological evaluation of dual acting ligands targeting the adenosine A2A and dopamine D2 receptors for the potential treatment of Parkinson's disease.

    Science.gov (United States)

    Jörg, Manuela; May, Lauren T; Mak, Frankie S; Lee, Kiew Ching K; Miller, Neil D; Scammells, Peter J; Capuano, Ben

    2015-01-22

    A relatively new strategy in drug discovery is the development of dual acting ligands. These molecules are potentially able to interact at two orthosteric binding sites of a heterodimer simultaneously, possibly resulting in enhanced subtype selectivity, higher affinity, enhanced or modified physiological response, and reduced reliance on multiple drug administration regimens. In this study, we have successfully synthesized a series of classical heterobivalent ligands as well as a series of more integrated and "drug-like" dual acting molecules, incorporating ropinirole as a dopamine D2 receptor agonist and ZM 241385 as an adenosine A2A receptor antagonist. The best compounds of our series maintained the potency of the original pharmacophores at both receptors (adenosine A2A and dopamine D2). In addition, the integrated dual acting ligands also showed promising results in preliminary blood-brain barrier permeability tests, whereas the classical heterobivalent ligands are potentially more suited as pharmacological tools.

  9. Thoracic applications of dual-source CT technology.

    Science.gov (United States)

    Boroto, Kahimano; Remy-Jardin, Martine; Flohr, Thomas; Faivre, Jean-Baptiste; Pansini, Vittorio; Tacelli, Nunzia; Schmidt, Bernhard; Gorgos, Andrei; Remy, Jacques

    2008-12-01

    Among the various imaging modalities available, CT has remained over time the core imaging technique for the evaluation of respiratory disorders. The recent advent of dual-source CT offers innovative approaches to investigate thoracic diseases, based on the use of one or two tubes as well as single or dual energy to scan the entire thorax. Two major options can be used in clinical practice with promising results. Dual source, single-energy scanning allows scanning of the entire thorax with ultra-high temporal resolution which opens the field of integrated cardiothoracic imaging without ECG gating as well as optimized evaluation of pediatric and adult patients with limited ability to cooperate. Dual-source, dual-energy acquisitions represent another very innovative means of investigating respiratory disorders, adding tissue characterization and functional analysis to morphological evaluation. The purpose of this review article is to provide results on preliminary experiences with the above-mentioned scanning conditions with dual-source CT and to envisage potential forthcoming applications in the field of thoracic imaging.

  10. Dual energy with dual source CT and kVp switching with single source CT: a comparison of dual energy performance

    Science.gov (United States)

    Grasruck, M.; Kappler, S.; Reinwand, M.; Stierstorfer, K.

    2009-02-01

    Stimulated by the introduction of clinical dual source CT, the interest in dual energy methods has been increasing in the past years. Whereas the potential of material decomposition by dual energy methods is known since the early 1980ies, the realization of dual energy methods is a wide field of today's research. Energy separation can be achieved with energy selective detectors or by varying X-ray source spectra. This paper focuses on dual energy techniques with varying X-ray spectra. These can be provided by dual source CT devices, operated with different kVp settings on each tube. Excellent spectral separation is the key property for use in clinical routine. The drawback of higher cost for two tubes and two detectors leads to an alternative realization, where a single source CT yields different spectra by fast kVp switching from reading to reading. This provides access to dual-energy methods in single source CT. However, this technique comes with some intrinsic limitations. The maximum X-ray flux is reduced in comparison to the dual source system. The kVp rise and fall time between each reading reduces the spectral separation. In comparison to dual source CT, for a constant number of projections per energy spectrum the temporal resolution is reduced; a reasonable trade of between reduced numbers of projection and limited temporal resolution has to be found. The overall dual energy performance is the guiding line for our investigations. We present simulations and measurements which benchmark both solutions in terms of spectral behavior, especially of spectral separation.

  11. Cerebral artery evaluation of dual energy CT angiography with dual source CT

    Institute of Scientific and Technical Information of China (English)

    MA Rui; LIU Cheng; DENG Kai; SONG Shao-juan; WANG Dao-ping; HUANG Ling

    2010-01-01

    Background Conventional computed tomography angiography (CTA) is time consuming, user-dependent and has poor image quality in skull base region. This study assessed the feasibility of a new method, dual energy CTA for depicting the cerebral artery.Methods Phantom scan was done with head CTA sequences on dual source CT and 64 spiral CT for radiation dose calculation. Dual energy CTA was done with dual source CT on 36 patients who were suspected of having cerebral vascular disease. Three series axial images in 0.75 mm thick, 0.4 mm increment were acquired, which were named with 80 kV, 140 kV and merged images; 80 kV and 140 kV images were transferred into dual energy software, and maximum intensity projection (MIP) image was generated quickly by dual energy bone remove (DEBR group); merged images were transferred into In Space software to acquire MIP image through manual conventional bone remove (CoBR group). Post processing time and reading time were compared. Image qualities of the two groups were compared, mainly focusing on skull base segments of internal carotid artery and bone subtraction. ANOVA and SNK tests were applied for radiation dose comparison. Student's t test and Wilcoxon rank sum test were applied for assessing differences between data for significance. Cohen's kappa was used for interobserver agreement. Results Radiation dose of phantom scan showed dual energy CTA was between digital bone subtraction and conventional CTA. The post processing time and reading time were much shorter in DEBR than CoBR, and image quality in skull base was much higher in DEBR than CoBR (P0.5). Interobserver agreement for all vessel segments was excellent (kappa=0.97). Conclusions Dual energy CTA is a reliable, new modality for depicting cerebral artery, overcoming the limitation of conventional CTA in the skull base region. It can save much time in post processing and reading than conventional CTA.

  12. The HelCat dual-source plasma device.

    Science.gov (United States)

    Lynn, Alan G; Gilmore, Mark; Watts, Christopher; Herrea, Janis; Kelly, Ralph; Will, Steve; Xie, Shuangwei; Yan, Lincan; Zhang, Yue

    2009-10-01

    The HelCat (Helicon-Cathode) device has been constructed to support a broad range of basic plasma science experiments relevant to the areas of solar physics, laboratory astrophysics, plasma nonlinear dynamics, and turbulence. These research topics require a relatively large plasma source capable of operating over a broad region of parameter space with a plasma duration up to at least several milliseconds. To achieve these parameters a novel dual-source system was developed utilizing both helicon and thermionic cathode sources. Plasma parameters of n(e) approximately 0.5-50 x 10(18) m(-3) and T(e) approximately 3-12 eV allow access to a wide range of collisionalities important to the research. The HelCat device and initial characterization of plasma behavior during dual-source operation are described.

  13. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy

    Science.gov (United States)

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-01

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  14. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy.

    Science.gov (United States)

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-01

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  15. Dual-wavelength laser source for onboard atom interferometry

    CERN Document Server

    Ménoret, Vincent; Stern, Guillaume; Zahzam, Nassim; Battelier, Baptiste; Bresson, Alexandre; Landragin, Arnaud; Bouyer, Philippe

    2011-01-01

    We present a compact and stable dual-wavelength laser source for onboard atom interferometry with two different atomic species. It is based on frequency-doubled telecom lasers locked on a femtosecond optical frequency comb. We take advantage of the maturity of fiber telecom technology to reduce the number of free-space optical components which are intrinsically less stable, and to make the setup immune to vibrations and thermal fluctuations. The source provides the frequency agility and phase stability required for atom interferometry and can easily be adapted to other cold atom experiments. We have shown its robustness by achieving the first dual-species K-Rb magneto optical trap in microgravity during parabolic flights.

  16. Dual-wavelength laser source for onboard atom interferometry.

    Science.gov (United States)

    Ménoret, V; Geiger, R; Stern, G; Zahzam, N; Battelier, B; Bresson, A; Landragin, A; Bouyer, P

    2011-11-01

    We present a compact and stable dual-wavelength laser source for onboard atom interferometry with two different atomic species. It is based on frequency-doubled telecom lasers locked on a femtosecond optical frequency comb. We take advantage of the maturity of fiber telecom technology to reduce the number of free-space optical components, which are intrinsically less stable, and to make the setup immune to vibrations and thermal fluctuations. The source provides the frequency agility and phase stability required for atom interferometry and can easily be adapted to other cold atom experiments. We have shown its robustness by achieving the first dual-species K-Rb magneto-optical trap in microgravity during parabolic flights.

  17. CORONARY ANGIOGRAPHY WITH DUAL SOURCE COMPUTED TOMOGRAPHY: INITIAL EXPERIENCE

    Institute of Scientific and Technical Information of China (English)

    Zhu-hua Zhang; Wen-min Zhao; Wen-bin Mou; Li-ren Zhang; Wen-ling Zhu; Qi Miao; Qi Fang; Zheng-yu Jin; Shu-yang Zhang; Song-bai Lin; Dong-jing Li; Ling-yan Kong; Yi-ning Wang; Lan Song; Yun Wang

    2007-01-01

    To explore the scan technique and image quality of coronary angiography with dual source computed tomography (CT) without oral metoprolol preparation.Methods Plain and enhanced dual source CT coronary angiography without oral metoprolol preparation was prospectively performed in 600 patients. Calcium scoring with plain scan images as well as multi-planar reconstruction( MPR ), maximum intensity projection (MIP), and volume rendering technique (VRT) reconstruction with enhanced scan images were performed in all cases. The scan technique and post-reconstruction experience was summarized. The image quality was classified as 1 to 4 points, and coronary segments classified according to the American Heart Association standards were evaluated.Results The average calcium score of the 600 cases was 213.6 ± 298.7 (0-3 216. 5). The average heart rate of the enhanced scan was 82.1 ± 16.2 (47-139) bpm. The post-reconstruction methods with which coronary segments could be shown as best as possible consisted of single phase reconstruction method, two or more phases supplemented method, and electrocardiogram editing method. Altogether 8 457 coronary segments were evaluated, among which 97.2% were evaluated as point 1, 1.7% point 2, 0.5% point 3, and0.6% point 4. The coronary segments in 261 cases were completely normal, while 360 segments were diagnosed with < 50% stenosis and 625 segments with ≥50%stenosis.Conclusions Excellent coronary artery image can be obtained with dual source CT in patients with any heart rate without oral metoprolol preparation. Heart rate is not a major source of the artifact, coronary segments can be well shown with single or multiple-phase reconstruction method.

  18. The utilization of dual source CT in imaging of polytrauma

    Energy Technology Data Exchange (ETDEWEB)

    Nicolaou, S. [University of British Columbia, Vancouver General Hospital, Department of Radiology, 899 West 12th Avenue, Vancouver, British Columbia, V5Z1M9 (Canada)], E-mail: savvas.nicolaou@vch.ca; Eftekhari, A.; Sedlic, T.; Hou, D.J.; Mudri, M.J.; Aldrich, John; Louis, L. [University of British Columbia, Vancouver General Hospital, Department of Radiology, 899 West 12th Avenue, Vancouver, British Columbia, V5Z1M9 (Canada)

    2008-12-15

    Despite the growing role of imaging, trauma remains the leading cause of death in people below the age of 45 years in the western industrialized countries. Trauma has been touted as the largest epidemic in the 20th century. The advent of MDCT has been the greatest advance in trauma care in the last 25 years. However, there are still challenges in CT imaging of the polytrauma individual including time restraints, diagnostic errors, radiation dose effects and bridging the gap between anatomy and physiology. This article will analyze these challenges and provide possible solutions offered by the unique design of the dual source CT scanner.

  19. On-chip dual comb source for spectroscopy

    CERN Document Server

    Dutt, Avik; Ji, Xingchen; Cardenas, Jaime; Okawachi, Yoshitomo; Luke, Kevin; Gaeta, Alexander L; Lipson, Michal

    2016-01-01

    Dual-comb spectroscopy is a powerful technique for real-time, broadband optical sampling of molecular spectra which requires no moving components. Recent developments with microresonator-based platforms have enabled frequency combs at the chip scale. However, the need to precisely match the resonance wavelengths of distinct high-quality-factor microcavities has hindered the development of an on-chip dual comb source. Here, we report the first simultaneous generation of two microresonator combs on the same chip from a single laser. The combs span a broad bandwidth of 51 THz around a wavelength of 1.56 $\\mu$m. We demonstrate low-noise operation of both frequency combs by deterministically tuning into soliton mode-locked states using integrated microheaters, resulting in narrow ($<$ 10 kHz) microwave beatnotes. We further use one mode-locked comb as a reference to probe the formation dynamics of the other comb, thus introducing a technique to investigate comb evolution without auxiliary lasers or microwave os...

  20. Coronary revascularization treatment based on dual-source computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Dikkers, R.; Willems, T.P.; Jonge, G.J. de; Zaag-Loonen, H.J. van der; Ooijen, P.M.A. van; Oudkerk, M. [University of Groningen, Department of Radiology, Groningen (Netherlands); University Medical Center, Groningen (Netherlands); Piers, L.H.; Tio, R.A.; Zijlstra, F. [University of Groningen, Department of Cardiology, Groningen (Netherlands); University Medical Center, Groningen (Netherlands)

    2008-09-15

    Therapy advice based on dual-source computed tomography (DSCT) in comparison with coronary angiography (CAG) was investigated and the results evaluated after 1-year follow-up. Thirty-three consecutive patients (mean age 61.9 years) underwent DSCT and CAG and were evaluated independently. In an expert reading (the ''gold standard''), CAG and DSCT examinations were evaluated simultaneously by an experienced radiologist and cardiologist. Based on the presence of significant stenosis and current guidelines, therapy advice was given by all readers blinded from the results of other readings and clinical information. Patients were treated based on a multidisciplinary team evaluation including all clinical information. In comparison with the gold standard, CAG had a higher specificity (91%) and positive predictive value (PPV) (95%) compared with DSCT (82% and 91%, respectively). DSCT had a higher sensitivity (96%) and negative predictive value (NPV) (89%) compared with CAG (91% and 83%, respectively). The DSCT-based therapy advice did not lead to any patient being denied the revascularization they needed according to the multidisciplinary team evaluation. During follow-up, two patients needed additional revascularization. The high NPV for DSCT for revascularization assessment indicates that DSCT could be safely used to select patients benefiting from medical therapy only. (orig.)

  1. DualSPHysics: Open-source parallel CFD solver based on Smoothed Particle Hydrodynamics (SPH)

    Science.gov (United States)

    Crespo, A. J. C.; Domínguez, J. M.; Rogers, B. D.; Gómez-Gesteira, M.; Longshaw, S.; Canelas, R.; Vacondio, R.; Barreiro, A.; García-Feal, O.

    2015-02-01

    DualSPHysics is a hardware accelerated Smoothed Particle Hydrodynamics code developed to solve free-surface flow problems. DualSPHysics is an open-source code developed and released under the terms of GNU General Public License (GPLv3). Along with the source code, a complete documentation that makes easy the compilation and execution of the source files is also distributed. The code has been shown to be efficient and reliable. The parallel power computing of Graphics Computing Units (GPUs) is used to accelerate DualSPHysics by up to two orders of magnitude compared to the performance of the serial version.

  2. Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede;

    2007-01-01

    . Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays...... in the dual-inverter PWM scheme, its switched common-mode voltage can be completely eliminated, unlike in traditional inverters, where narrow common-mode spikes are still generated. Under semiconductor failure conditions, the presented PWM schemes can easily be modified to allow the inverter to operate......This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck...

  3. Diagnostic value of dual-source CT in Kawasaki disease

    Institute of Scientific and Technical Information of China (English)

    CHAO Bao-ting; WANG Xi-ming; WU Le-bin; CHEN Jie; CHENG Zhao-ping; WU Da-wei; DUAN Yan-hua

    2010-01-01

    Background Doppler color echocardiography is a common method for detecting coronary artery lesions in patients with Kawasaki disease(KD).However,the diagnostic accuracy for the whole coronary artery lesions is limited.The purpose of this study was to compare the diagnostic value of dual-source computed tomography (DSCT) and Doppler color echocardiography for the assessment of coronary artery lesions caused by KD.Methods Sixteen patients,12 with typical KD and 4 with atypical KD,underwent DSCT and Doppler color echocardiography.The position and internal diameter of each coronary artery lesion was measured.Correlation analysis was used to compare the diagnostic value of the two imaging modalities.Results ln the typical KD group, seven patients did not have any coronary artery Iesion as confirmed by both DSCT scans and Doppler color echocardiography;in four patients proximal coronary artery injuries were identified by both modalities;in one patient an aneurysm in the middle and distal segments of the coronary artery was detected by DSCT but was negative in Doppler color echocardiography.In the atypical KD group,three cases showed the same results with both modalities,while one case with coronary artery stenosis in the middle segment was identified by DSCT but not detected by Doppler color echocardiography.There was a good correlation between the two imaging modalities(Kappa value,0.768(≥0.75)).Conclusion DSCT coronary artery angiography is an accurate,non-invasive,and valuable technique for detecting and following up coronary artery lesions in patients with KD.

  4. Regulation of adenosine levels during cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Stephanie CHU; Wei XIONG; Dali ZHANG; Hanifi SOYLU; Chao SUN; Benedict C ALBENSI; Fiona E PARKINSON

    2013-01-01

    Adenosine is a neuromodulator with its level increasing up to 100-fold during ischemic events,and attenuates the excitotoxic neuronal injury.Adenosine is produced both intracellularly and extracellularly,and nucleoside transport proteins transfer adenosine across plasma membranes.Adenosine levels and receptor-mediated effects of adenosine are regulated by intracellular ATP consumption,cellular release of ATP,metabolism of extracellular ATP (and other adenine nucleotides),adenosine influx,adenosine efflux and adenosine metabolism.Recent studies have used genetically modified mice to investigate the relative contributions of intra-and extracellular pathways for adenosine formation.The importance of cortical or hippocampal neurons as a source or a sink of adenosine under basal and hypoxic/ischemic conditions was addressed through the use of transgenic mice expressing human equilibrative nucleoside transporter 1 (hENT1) under the control of a promoter for neuron-specific enolase.From these studies,we conclude that ATP consumption within neurons is the primary source of adenosine in neuronal cultures,but not in hippocampal slices or in vivo mice exposed to ischemic conditions.

  5. The dual role of external technology sourcing in technological exploration

    DEFF Research Database (Denmark)

    Vanhaverbeke, Wim; Li-Ying, Jason; van de Vrande, Vareska

    2013-01-01

    capital, or M&As). These partners play a dual role: in explorative learning from partners, a firm teams up with external venturing partners to co-develop or transfer technology. Partners’ technology base (what they know) is driving explorative learning from partners. In contrast, in explorative learning...... from non-partners, partners may play a role because of whom they know. That is, they inform the firm about technological opportunities beyond its corporate venturing network. The empirical analysis supports the dual role of venturing partners in facilitating the two types of explorative learning....

  6. Investigating the performance of SiGe embedded dual source p-FinFET architecture

    Science.gov (United States)

    Sinha, Kunal; Gupta, Partha Sarathi; Chattopadhyay, Sanatan; Rahaman, Hafizur

    2016-10-01

    In this work, a modified Fin shaped Field Effect Transistor (FinFET) structure has been proposed with dual SiGe embedded extended source regions. Comparative simulation studies with SiGe embedded source/drain conventional single Fin channel and dual Fin channel FinFET structure having similar device footprint area shows almost 3× and 1.5× improvement of drive current respectively and lower threshold voltage in the proposed architecture. The dual extended SiGe source regions and presence of Si drain in the vertical direction of the channel generate bi-axial channel stress which improves the channel charge density, which results in improvement in drive current significantly. Also it has been observed from various simulation studies that the separated gate regions increase the inversion current density in the channel which also leads to improvement of the device performance.

  7. Accurate reconstruction of temporal correlation for neuronal sources using the enhanced dual-core MEG beamformer.

    Science.gov (United States)

    Diwakar, Mithun; Tal, Omer; Liu, Thomas T; Harrington, Deborah L; Srinivasan, Ramesh; Muzzatti, Laura; Song, Tao; Theilmann, Rebecca J; Lee, Roland R; Huang, Ming-Xiong

    2011-06-15

    Beamformer spatial filters are commonly used to explore the active neuronal sources underlying magnetoencephalography (MEG) recordings at low signal-to-noise ratio (SNR). Conventional beamformer techniques are successful in localizing uncorrelated neuronal sources under poor SNR conditions. However, the spatial and temporal features from conventional beamformer reconstructions suffer when sources are correlated, which is a common and important property of real neuronal networks. Dual-beamformer techniques, originally developed by Brookes et al. to deal with this limitation, successfully localize highly-correlated sources and determine their orientations and weightings, but their performance degrades at low correlations. They also lack the capability to produce individual time courses and therefore cannot quantify source correlation. In this paper, we present an enhanced formulation of our earlier dual-core beamformer (DCBF) approach that reconstructs individual source time courses and their correlations. Through computer simulations, we show that the enhanced DCBF (eDCBF) consistently and accurately models dual-source activity regardless of the correlation strength. Simulations also show that a multi-core extension of eDCBF effectively handles the presence of additional correlated sources. In a human auditory task, we further demonstrate that eDCBF accurately reconstructs left and right auditory temporal responses and their correlations. Spatial resolution and source localization strategies corresponding to different measures within the eDCBF framework are also discussed. In summary, eDCBF accurately reconstructs source spatio-temporal behavior, providing a means for characterizing complex neuronal networks and their communication.

  8. Source book for planning nuclear dual-purpose electric/distillation desalination plants

    Energy Technology Data Exchange (ETDEWEB)

    Reed, S.A.

    1981-02-01

    A source book on nuclear dual-purpose electric/distillation desalination plants was prepared to assist government and other planners in preparing broad evaluations of proposed applications of dual-purpose plants. The document is divided into five major sections. Section 1 presents general discussions relating to the benefits of dual-purpose plants, and spectrum for water-to-power ratios. Section 2 presents information on commercial nuclear plants manufactured by US manufacturers. Section 3 gives information on distillation desalting processes and equipment. Section 4 presents a discussion on feedwater pretreatment and scale control. Section 5 deals with methods for coupling the distillation and electrical generating plants to operate in the dual mode.

  9. Signal-to-noise analysis for detection sensitivity of small absorbing heterogeneity in turbid media with single-source and dual-interfering-source.

    Science.gov (United States)

    Chen, Y; Mu, C; Intes, X; Chance, B

    2001-08-13

    Previous studies have suggested that the phased-array detection can achieve high sensitivity in detecting and localizing inhomogeneities embedded in turbid media by illuminating with dual interfering sources. In this paper, we analyze the sensitivity of single-source and dual-interfering-source (phased array) systems with signal-to-noise ratio criteria. Analytical solutions are presented to investigate the sensitivity of detection using different degrees of absorption perturbation by varying the size and contrast of the object under similar configurations for single- and dual-source systems. The results suggest that dual-source configuration can provide higher detection sensitivity. The relation between the amplitude and phase signals for both systems is also analyzed using a vector model. The results can be helpful for optimizing the experimental design by combining the advantages of both single- and dual-source systems in object detection and localization.

  10. Feasibility and accuracy of tissue characterization with dual source computed tomography

    NARCIS (Netherlands)

    Van Abbema, Joanne K.; Van der Schaaf, Arjen; Kristanto, Wisnu; Groen, Jaap M.; Greuter, Marcel J. W.

    2012-01-01

    PURPOSE: To evaluate the feasibility and accuracy of a model for tissue characterization with dual source computed tomography (DSCT). METHODS AND MATERIALS: A model for tissue characterization in CT was used with a parameterization of linear attenuation coefficients. Sixteen chemical substances with

  11. Visualization of anomalous coronary arteries on dual-source computed tomography

    NARCIS (Netherlands)

    de Jonge, G. J.; van Ooijen, P. M. A.; Piers, L. H.; Dikkers, R.; Tio, R. A.; Willems, T. P.; van den Heuvel, A. F. M.; Zijlstra, F.; Oudkerk, M.

    2008-01-01

    The purpose of this study is to assess the capability of dual-source computed tomography (DSCT) in evaluating coronary artery anomalies. Early detection and evaluation of coronary artery anomalies is essential because of their potential association with myocardial ischemia and sudden death. In 16 pa

  12. Dual color x-rays from Thomson or Compton sources

    Science.gov (United States)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Ferrario, M.; Maroli, C.; Rau, J. V.; Ronsivalle, C.; Serafini, L.; Vaccarezza, C.; Venturelli, M.

    2015-05-01

    We analyze the possibility of producing two color X or γ radiation by Thomson/Compton back-scattering between a high intensity laser pulse and a two-energy level electron beam, constituted by a couple of beamlets separated in time and/or energy obtained by a photoinjector with comb laser techniques and linac velocity bunching. The parameters of the Thomson source at SPARC_LAB have been simulated, proposing a set of values for a realistic experiments.

  13. Dual color x rays from Thomson or Compton sources

    Science.gov (United States)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Ferrario, M.; Gatti, G.; Maroli, C.; Rau, J. V.; Ronsivalle, C.; Serafini, L.; Vaccarezza, C.; Venturelli, M.

    2014-02-01

    We analyze the possibility of producing two-color x or γ radiation by Thomson/Compton backscattering between a high intensity laser pulse and a two-energy level electron beam, constituted by a couple of beamlets separated in time and/or energy obtained by a photoinjector with comb laser techniques and linac velocity bunching. The parameters of the Thomson source at SPARC_LAB have been simulated, proposing a set of realistic experiments.

  14. Design of triode extraction system for a dual hollow cathode ion source

    Institute of Scientific and Technical Information of China (English)

    WANG Jing-Hui; ZHU Kun; ZHAO Wei-Jiang; LIU Ke-Xin

    2011-01-01

    A triode extraction system is designed for a dual hollow cathode ion source being developed at the Institute of Heavy Ion Physics,Peking University.Basic parameters of the plasma are selected after examining the operation principle of the ion source,then the triode extraction system is designed and optimized by using software PBGUNS (for Particle Beam GUN Simulations).The physical design of the system is given in this paper.

  15. Adenosine and adenosine receptors: Newer therapeutic perspective

    Directory of Open Access Journals (Sweden)

    Manjunath S

    2009-01-01

    Full Text Available Adenosine, a purine nucleoside has been described as a ′retaliatory metabolite′ by virtue of its ability to function in an autocrine manner and to modify the activity of a range of cell types, following its extracellular accumulation during cell stress or injury. These effects are largely protective and are triggered by binding of adenosine to any of the four adenosine receptor subtypes namely A1, A2a, A2b, A3, which have been cloned in humans, and are expressed in most of the organs. Each is encoded by a separate gene and has different functions, although overlapping. For instance, both A1 and A2a receptors play a role in regulating myocardial oxygen consumption and coronary blood flow. It is a proven fact that adenosine plays pivotal role in different physiological functions, such as induction of sleep, neuroprotection and protection against oxidative stress. Until now adenosine was used for certain conditions like paroxysmal supraventricular tachycardia (PSVT and Wolff Parkinson White (WPW syndrome. Now there is a growing evidence that adenosine receptors could be promising therapeutic targets in a wide range of conditions including cardiac, pulmonary, immunological and inflammatory disorders. After more than three decades of research in medicinal chemistry, a number of selective agonists and antagonists of adenosine receptors have been discovered and some have been clinically evaluated, although none has yet received regulatory approval. So this review focuses mainly on the newer potential role of adenosine and its receptors in different clinical conditions.

  16. Dual arc penning ion source gas flow experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, E.D.; Lord, R.S.; Mallory, M.L.; Antaya, T.A.

    1984-01-01

    Support gas, when added directly to an arc or admitted to an auxiliary chamber of a two-arc chamber ion source, increases the beam intensity for multicharged ions such as /sup 16/O/sup 5 +/. To clarify the mechanism of this intensity increase, gas flow rates from the auxiliary chamber to the main chamber have been measured by using the ORIC cyclotron as a mass spectrometer. The results show that only about three percent of the gas admitted to the auxiliary chamber reaches the main chamber. One can then infer that the improved operation probably results from the stabilizing effect of heating the common cathodes with the auxiliary arc and/or the more favorable distribution of the support gas to the part of the main arc close to the cathodes.

  17. Attenuation-based characterization of coronary atherosclerotic plaque: Comparison of dual source and dual energy CT with single-source CT and histopathology

    Energy Technology Data Exchange (ETDEWEB)

    Henzler, Thomas, E-mail: Thomas.Henzler@umm.de [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim (Germany); Porubsky, Stefan [Department of Pathology, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim (Germany); Kayed, Hany [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim (Germany); Harder, Nils [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim (Germany); Department of Pathology, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim (Germany); Krissak, U. Radko; Meyer, Mathias [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim (Germany); Sueselbeck, Tim [1st Department of Medicine University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim (Germany); Marx, Alexander [Department of Pathology, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim (Germany); Michaely, Henrik [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim (Germany); Schoepf, U. Joseph [Department of Radiology and Radiological Science, Medical University of South Carolina, 169 Ashley Avenue, Charleston (United States)

    2011-10-15

    Objective: To compare different CT acquisition techniques regarding for attenuation-based characterization of coronary atherosclerotic plaques using histopathology as the standard of reference. Materials and methods: In a post mortem study 17 human hearts were studied with dual-source CT (DSCT) and dual energy CT (DECT) mode on a DSCT as well as with 16-slice single-source CT (SSCT). At autopsy, atherosclerotic lesions were cut at 5 {mu}m sections. Histopathologic classification of the plaques according to the American Heart Association (AHA) criteria was performed by two pathologists. Attenuation values of all plaques were measured in DSCT, DECT and SSCT studies, respectively and classified based on attenuation according to modified AHA criteria. Results: 58 coronary plaques were identified at autopsy. Regardless of the CT technique only 52/58 plaques were found at CT (sensitivity = 89.6%). There was no significant difference between the mean attenuation values of different plaque types between DSCT, DECT, and SSCT: type IV: 11 HU/8 HU/19 HU; type Va: 44 HU/45 HU/52 HU; type Vb: 1088 HU/966 HU/1079 HU). The sensitivity for correct classification varied depending on the plaque type (type II = 0%, type III = 0%, type IV = 43%, type Va = 58%, Vb = 97%). Conclusion: Independent of the used acquisition technique, SSCT, DSCT and DECT show similar results for attenuation-based characterization of atherosclerotic coronary plaques.

  18. Bicomponent Fibrous Scaffolds Made through Dual-source Dual-power Electrospinning: Dual Delivery of rhBMP-2 and Ca-P Nanoparticles and Enhanced Biological Performances.

    Science.gov (United States)

    Wang, Chong; Weijia Lu, William; Wang, Min

    2017-04-05

    Electrospun scaffolds incorporated with both calcium phosphates (Ca-P) and bone morphogenetic protein-2 (BMP-2) have been used for bone tissue regeneration. However, in most cases BMP-2 and Ca-P were simply mixed and loaded in a monolithic structure, risking low BMP-2 loading level, reduced BMP-2 biological activity, uncontrolled BMP-2 release and inhomogeneous Ca-P distribution. In this investigation, novel bicomponent scaffolds having evenly distributed rhBMP-2-containing fibers and Ca-P nanoparticle-containing fibers were made using an established dual-source dual-power electrospinning technique with the assistance of emulsion electrospinning and blend electrospinning. The release behaviour of rhBMP-2 and Ca(2+) ions could be separately tuned and the released rhBMP-2 retained a 68% level for biological activity. MC3T3-E1 cells showed high viability and normal morphology on scaffolds. Compared to monocomponent scaffolds, enhanced cell proliferation, alkaline phosphatase activity, cell mineralization and gene expression of osteogenic markers were achieved for bicomponent scaffolds due to the synergistic effect of rhBMP-2 and Ca-P nanoparticles. Bicomponent scaffolds with a double mass elicited further enhanced cell adhesion, spreading, proliferation and osteogenic differentiation. This article is protected by copyright. All rights reserved.

  19. Dichromatic source for the application of dual-energy tissue cancellation in mammography

    Science.gov (United States)

    Tuffanelli, Alessandra; Fabbri, S.; Marziani, Michele; Taibi, Angelo; Sarnelli, A.; Gambaccini, Mauro

    2002-05-01

    A novel x-ray source, providing dichromatic beams for the application of dual-energy radiography, has been assembled and studied. The system works via Bragg diffraction, by monochromatizing the beam produced by a conventional W-anode x-ray tube with a mosaic crystal monochromator. The source generates a laminar beam (10 cm-high and 0.8 cm-wide), composed by two spatially superimposed quasi-monochromatic beams. The characteristics of the radiation field in terms of energy resolution and fluence have been reported, for three pairs of energies. A study of the spectra attenuated by several phantoms of breast equivalent tissue of different thicknesses shows that the optimal energy of the dichromatic beam for dual energy mammography application ranges between 18/36 keV and 18.6/37.2 keV and may be set as a function of the thickness or density of investigated tissue.

  20. Correlation of radiation dose and heart rate in dual-source computed tomography coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Laspas, Fotios; Roussakis, Arkadios; Kritikos, Nikolaos; Efthimiadou, Roxani; Kehagias, Dimitrios; Andreou, John (CT and MRI Dept., Hygeia Hospital, Athens (Greece)), e-mail: fotisdimi@yahoo.gr; Tsantioti, Dimitra (Statistician, Hygeia Hospital, Athens (Greece))

    2011-04-15

    Background: Computed tomography coronary angiography (CTCA) has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but the relatively high radiation dose remains a major concern. Purpose: To evaluate the relationship between radiation exposure and heart rate (HR), in dual-source CTCA. Material and Methods: Data from 218 CTCA examinations, performed with a dual-source 64-slices scanner, were statistically evaluated. Effective radiation dose, expressed in mSv, was calculated as the product of the dose-length product (DLP) times a conversion coefficient for the chest (mSv = DLPx0.017). Heart rate range and mean heart rate, expressed in beats per minute (bpm) of each individual during CTCA, were also provided by the system. Statistical analysis of effective dose and heart rate data was performed by using Pearson correlation coefficient and two-sample t-test. Results: Mean HR and effective dose were found to have a borderline positive relationship. Individuals with a mean HR >65 bpm observed to receive a statistically significant higher effective dose as compared to those with a mean HR =65 bpm. Moreover, a strong correlation between effective dose and variability of HR of more than 20 bpm was observed. Conclusion: Dual-source CT scanners are considered to have the capability to provide diagnostic examinations even with high HR and arrhythmias. However, it is desirable to keep the mean heart rate below 65 bpm and heart rate fluctuation less than 20 bpm in order to reduce the radiation exposure

  1. Supercontinuum optimization for dual-soliton based light sources using genetic algorithms in a grid platform

    OpenAIRE

    ARTEAGA SIERRA, FRANCISCO RODRIGO; Milián Enrique, Carles; I. Torres-Gómez; M. Torres-Cisneros; Moltó, Germán; Ferrando Cogollos, Albert

    2014-01-01

    © 2014 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited We present a numerical strategy to design fiber based dual pulse light sources exhibiting two predefined spectral peaks in the anomalous group velocity dispersion regime. The frequency conversion is based on t...

  2. 双源CT的临床应用进展%Development and Clinical Application of Dual-Source CT

    Institute of Scientific and Technical Information of China (English)

    徐辉; 殷信道; 吴旻

    2014-01-01

    In 2005 and 2008, Siemens launched the 昀rst and second generation Dual Source CT system. This paper reviews the basic structure, characteristics, advantages and application of Dual Source CT system.%2005年、2008年西门子相继推出第一代双源CT Definition(Dual Source Computed Tomography, DSCT)、第二代双源CT(SOMATOM De昀nition Flash),本文主要就双源CT的基本结构、特点、优势以及在临床应用方面的进展作一综述。

  3. Evaluation of a dichromatic X-ray source for dual-energy imaging in mammography

    Science.gov (United States)

    Tuffanelli, A.; Fabbri, S.; Sarnelli, A.; Taibi, A.; Gambaccini, M.

    2002-08-01

    A novel X-ray system, providing dichromatic beams for dual-energy radiography, has been assembled. The source generates pairs of superimposed quasi-monochromatic beams, having energies E and 2 E, with E tuneable in the 15-20 keV range. In this paper the characteristics of the radiation field in terms of energy resolution and fluence, for three dichromatic X-ray beams are reported. A study of the spectra attenuated by a 5 cm-thick phantom of breast equivalent tissue demonstrates that the optimal energy of the dichromatic beam for dual-energy application may be set as a function of the thickness of investigated tissue. A detailed topographic study of mean energy and flux shows the spatial superposition of the first and the second diffraction order beam, that is the main requirement for the application of a single exposure dual-energy radiography. The bidimensional mapping of the irradiated beam is also reported, showing the presence of energy and intensity gradients. We estimate that the observed gradients do not affect the results of dual-energy technique application in an appreciable way.

  4. Investigating whether it is optimal to make replenishments simultaneously in dual source model

    DEFF Research Database (Denmark)

    Abginehchi, Soheil; Larsen, Christian

    be relaxed. We study a dual source system with non-identical suppliers and model the problem as a semi-Markov decision model, allowing the decision maker the choice whether he will simultaneously issue two orders to both suppliers or he will issue the orders to suppliers at two different times.......In multiple sourcing, when supplier lead times are stochastic it makes sense to split any replenishment order into several smaller orders to pool lead time risks. In literature it is always assumed these orders are issued simultaneously to the suppliers. Here we let this simultaneousness assumption...

  5. Performance analysis of air——water dual source heat pump water heater with heat recovery

    Institute of Scientific and Technical Information of China (English)

    CHEN ZeShao; TAO WenQuan; ZHU YanWen; HU Peng

    2012-01-01

    A new air-water dual source heat pump water heater with heat recovery is proposed.The heat pump system can heat water by using a single air source,a single water source,or air-water dual sources.The water is first pre-heated by waste hot water,then heated by the heat pump.Waste heat is recovered by first preheating the cold water and as water source of the heat pump.According to the correlated formulas of the coefficient of performance of air-source heat pump and water-source heat pump,and the gain coefficient of heat recovery-preheater,the formulas for the coefficient of performance of heat pump in six operating modes are obtained by using the dimensionless correspondence analysis method.The system characteristics of heat absorption and release associated with the heat recovery-preheater are analyzed at different working conditions.The developed approaches can provide reference for the optimization of the operating modes and parameters.The results of analysis and experiments show that the coefficient of performance of the device can reach 4-5.5 in winter,twice as much as air source heat pump water heater.The utilization of waste heat in the proposed system is higher than that in the system which only uses waste water to preheating or as heat source.Thus,the effect of energy saving of the new system is obvious.On the other hand,the dimensionless correspondence analysis method is introduced to performance analysis of the heat pump,which also has theoretical significance and practical value.

  6. Electrostatic energy harvesting device with dual resonant structure for wideband random vibration sources at low frequency

    Science.gov (United States)

    Zhang, Yulong; Wang, Tianyang; Zhang, Ai; Peng, Zhuoteng; Luo, Dan; Chen, Rui; Wang, Fei

    2016-12-01

    In this paper, we present design and test of a broadband electrostatic energy harvester with a dual resonant structure, which consists of two cantilever-mass subsystems each with a mass attached at the free edge of a cantilever. Comparing to traditional devices with single resonant frequency, the proposed device with dual resonant structure can resonate at two frequencies. Furthermore, when one of the cantilever-masses is oscillating at resonance, the vibration amplitude is large enough to make it collide with the other mass, which provides strong mechanical coupling between the two subsystems. Therefore, this device can harvest a decent power output from vibration sources at a broad frequency range. During the measurement, continuous power output up to 6.2-9.8 μW can be achieved under external vibration amplitude of 9.3 m/s2 at a frequency range from 36.3 Hz to 48.3 Hz, which means the bandwidth of the device is about 30% of the central frequency. The broad bandwidth of the device provides a promising application for energy harvesting from the scenarios with random vibration sources. The experimental results indicate that with the dual resonant structure, the vibration-to-electricity energy conversion efficiency can be improved by 97% when an external random vibration with a low frequency filter is applied.

  7. Quantitative assessment of scatter correction techniques incorporated in next generation dual-source computed tomography

    Science.gov (United States)

    Mobberley, Sean David

    Accurate, cross-scanner assessment of in-vivo air density used to quantitatively assess amount and distribution of emphysema in COPD subjects has remained elusive. Hounsfield units (HU) within tracheal air can be considerably more positive than -1000 HU. With the advent of new dual-source scanners which employ dedicated scatter correction techniques, it is of interest to evaluate how the quantitative measures of lung density compare between dual-source and single-source scan modes. This study has sought to characterize in-vivo and phantom-based air metrics using dual-energy computed tomography technology where the nature of the technology has required adjustments to scatter correction. Anesthetized ovine (N=6), swine (N=13: more human-like rib cage shape), lung phantom and a thoracic phantom were studied using a dual-source MDCT scanner (Siemens Definition Flash. Multiple dual-source dual-energy (DSDE) and single-source (SS) scans taken at different energy levels and scan settings were acquired for direct quantitative comparison. Density histograms were evaluated for the lung, tracheal, water and blood segments. Image data were obtained at 80, 100, 120, and 140 kVp in the SS mode (B35f kernel) and at 80, 100, 140, and 140-Sn (tin filtered) kVp in the DSDE mode (B35f and D30f kernels), in addition to variations in dose, rotation time, and pitch. To minimize the effect of cross-scatter, the phantom scans in the DSDE mode was obtained by reducing the tube current of one of the tubes to its minimum (near zero) value. When using image data obtained in the DSDE mode, the median HU values in the tracheal regions of all animals and the phantom were consistently closer to -1000 HU regardless of reconstruction kernel (chapters 3 and 4). Similarly, HU values of water and blood were consistently closer to their nominal values of 0 HU and 55 HU respectively. When using image data obtained in the SS mode the air CT numbers demonstrated a consistent positive shift of up to 35 HU

  8. Coronary fly-through or virtual angioscopy using dual-source MDCT data.

    Science.gov (United States)

    van Ooijen, Peter M A; de Jonge, Gonda; Oudkerk, Matthijs

    2007-11-01

    Coronary fly-through or virtual angioscopy (VA) has been studied ever since its invention in 2000. However, application was limited because it requires an optimal computed tomography (CT) scan and time-consuming post-processing. Recent advances in post-processing software facilitate easy construction of VA, but until now image quality was insufficient in most patients. The introduction of dual-source multidetector CT (MDCT) could enable VA in all patients. Twenty patients were scanned using a dual-source MDCT (Definition, Siemens, Forchheim, Germany) using a standard coronary artery protocol. Post-processing was performed on an Aquarius Workstation (TeraRecon, San Mateo, Calif.). Length travelled per major branch was recorded in millimetres, together with the time required in minutes. VA could be performed in every patient for each of the major coronary arteries. The mean (range) length of the automated fly-through was 80 (32-107) mm for the left anterior descending (LAD), 75 (21-116) mm for the left circumflex artery (LCx), and 109 (21-190) mm for the right coronary artery (RCA). Calcifications and stenoses were visualised, as well as most side branches. The mean time required was 3 min for LAD, 2.5 min for LCx, and 2 min for the RCA. Dual-source MDCT allows for high quality visualisation of the coronary arteries in every patient because scanning with this machine is independent of the heart rate. This is clearly shown by the successful VA in all patients. Potential clinical value of VA should be determined in the near future.

  9. Supercontinuum optimization for dual-soliton based light sources using genetic algorithms in a Grid platform

    CERN Document Server

    Arteaga-Sierra, F R; Torres-Gómez, I; Torres-Cisneros, M; Moltó, G; Ferrando, A

    2014-01-01

    We present a numerical strategy to design fiber based dual pulse light sources exhibiting two predefined spectral peaks in the anomalous group velocity dispersion regime. The frequency conversion is based on the soliton fission and soliton self-frequency shift occurring during supercontinuum generation. The optimization process is carried out by a genetic algorithm that provides the optimum input pulse parameters: wavelength, temporal width and peak power. This algorithm is implemented in a Grid platform in order to take advantage of distributed computing. These results are useful for optical coherence tomography applications where bell-shaped pulses located in the second near-infrared window are needed.

  10. Dual-etalon cavity ring-down frequency-comb spectroscopy with broad band light source

    Science.gov (United States)

    Chandler, David W; Strecker, Kevin E

    2014-04-01

    In an embodiment, a dual-etalon cavity-ring-down frequency-comb spectrometer system is described. A broad band light source is split into two beams. One beam travels through a first etalon and a sample under test, while the other beam travels through a second etalon, and the two beams are recombined onto a single detector. If the free spectral ranges ("FSR") of the two etalons are not identical, the interference pattern at the detector will consist of a series of beat frequencies. By monitoring these beat frequencies, optical frequencies where light is absorbed may be determined.

  11. Clinical application of dual-source CT in the diagnosis of ALCAPA

    Institute of Scientific and Technical Information of China (English)

    程召平

    2014-01-01

    Objective To explore the clinical usefulness of anomalous origin of left coronary artery from the pulmonary artery(ALCAPA)by dual-source CT(DSCT)angiography.Methods A total of 10 patients(mean age5.1±5.0 yrs,age range 0.2-15 yrs;male 5)withALCAPA who underwent DSCT angiography and echocardiography were retrospectively included.Surgery was performed in 7 patients,and conventional cardiac angiography(CCA)in 4 patients.The subjective image quality was evaluated on a

  12. Preliminary experimental investigation of a complex dual-band high power microwave source

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoping, E-mail: zhangxiaoping@nudt.edu.cn; Li, Yangmei; Li, Zhiqiang; Zhong, Huihuang; Qian, Baoliang [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2015-10-15

    In order to promote the power conversion efficiency of a magnetically insulated transmission line oscillator (MILO) and obtain microwaves in dual bands, an axially extracted C-band virtual cathode oscillator (VCO) with multiple resonant cavities is introduced to partially utilize the load current of an S-band MILO. The formed novel dual-band high power microwave source called MILO and VCO is investigated with simulation and experimentally. A dual-band radiation antenna is designed to effectively radiate microwaves generated by the MILO and the VCO, respectively, while avoiding them being influenced by the microwave reflection and diffraction. The preliminary experimental results measured by the dual-band diagnostic system show that both the MILO and the VCO operate normally under repeated shots. A microwave of 2.1 GHz, 1.70 GW is generated from the MILO and a 0.37 GW microwave at frequencies of 4.1 GHz and 3.8 GHz is generated from the VCO under the condition of about 440 kV and 35 kA. Compared with a single MILO (10.6%), a MILO and VCO achieves higher total power and efficiency (13.4%) in both S and C bands, indicating that the load current of the MILO partially couples into the beam-wave interaction in the VCO and then contributes to the output microwaves. However, more works are needed regarding the spectrum purification of the VCO and promotion of the output power of both the MILO and the VCO.

  13. Dual-step prospective ECG-triggered 128-slice dual-source CT for evaluation of coronary arteries and cardiac function without heart rate control: a technical note

    Energy Technology Data Exchange (ETDEWEB)

    Feuchtner, Gudrun [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Innsbruck Medical University, Department of Radiology II, Innsbruck (Austria); Goetti, Robert; Marincek, Borut; Alkadhi, Hatem; Leschka, Sebastian [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Plass, Andre; Wieser, Monika [University Hospital Zurich, Clinic for Cardiovascular Surgery, Zurich (Switzerland); Baumueller, Stephan; Stolzmann, Paul; Scheffel, Hans [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); University Hospital Zurich, Clinic for Cardiovascular Surgery, Zurich (Switzerland)

    2010-09-15

    To describe prospective ECG-triggered dual-source CT dual-step pulsing (pECG{sub dual-step}) for evaluation of coronary arteries and cardiac function. Fifty-one consecutive patients pre- or post-cardiovascular surgery were examined with adaptive sequential tube current modulated (pECG{sub dual-step}) 128-slice dual-source CT without heart rate control (main padding window: 40% RR interval >65 bpm/70% RR interval <65 bpm). Image quality of coronary arteries was graded (4-point scale), and cardiac function was evaluated. Mean HR was 68 bpm. Thirty-seven patients were in stable sinus rhythm (SR); 14 had arrhythmia. Image quality of coronary arteries was diagnostic in 804/816 (98%) of segments. The number of non-diagnostic segments was higher in patients with arrhythmia as compared to those in SR (4% vs. 0.5%; p = 0.01), and there were fewer segments with excellent image quality (79% vs. 94%; p < 0.001) and more segments with impaired image quality (p < 0.001 and p = 0.002). Global and regional LV function could be evaluated in 41 (80%) and 47 (92%) patients, and valvular function in 48 (94%). In 11/14 of patients with arrhythmia, the second step switched to full mAs, increasing radiation exposure to 8.6 mAs (p < 0.001). The average radiation dose was 3.8 mSv (range, 1.7-7.9) in patients in SR. pECG{sub dual-step}128-slice DSCT is feasible for the evaluation of coronary arteries and cardiac function without heart rate control in patients in stable sinus rhythm at a low radiation dose. (orig.)

  14. Development of dual-source hybrid heat pump system using groundwater and air

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Yujin; Ooka, Ryozo [Cw403 Institute of Industry Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Shiba, Yoshiro [Zeneral Heatpump Industry Co., Ltd., Nagoya 459-8001 (Japan)

    2010-06-15

    To achieve high heat pump efficiency, groundwater heat pump (GWHP) system uses groundwater, which is relatively stable AT temperature compared with outdoor air, as a heat source. However, it is difficult to meet annual heating and cooling loads using only groundwater as a heat source. In order to optimize the operation method of GWHP systems, it is necessary to develop a system utilizing both groundwater and air sources according to the building load conditions. Furthermore, during intermediate seasons (such as spring and autumn) with reduced heating and cooling loads, GWHP system is less efficient than air source heat pump (ASHP) system according to temperature conditions. In order to more efficiently use GWHP systems, it is necessary to develop a system which utilizes both groundwater and air sources according to temperature conditions and building loads. This research has developed a GWHP system that employs a hybrid heat pump system with groundwater wells using dual groundwater and air heat sources. In this paper, the annual performance of the developed system has been calculated, and several case studies have been conducted on the effect of introduction location, refrigerant and pumping rate. Furthermore, the coefficient of system performance and the effects on underground environments have been evaluated by real-scale experiment using two wells. (author)

  15. Pre- and postsurgical diagnostics with dual-source computed tomography in cardiac surgery; Einsatz der Dual-source-Computertomographie in der prae- und postoperativen kardiochirurgischen Diagnostik

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaou, K.; Saam, T.; Rist, C.; Johnson, T.; Reiser, M.F.; Becker, C.R. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen, Institut fuer Klinische Radiologie, Muenchen (Germany); Vogt, F.; Oberhoffer, M.; Reichart, B. [Ludwig-Maximilians-Universitaet Muenchen, Herzchirurgische Klinik und Poliklinik, Muenchen (Germany)

    2007-04-15

    The aim of this study was to evaluate the clinical potential of dual-source computed tomography (DSCT) in pre- and postsurgical diagnostics in the field of cardiac surgery. A total of 20 patients underwent DSCT of the heart. This CT system with two rotating X-ray tubes (Somatom Definition, Siemens Medical Solutions, Forchheim, Germany) achieves a temporal resolution of 83 ms and a spatial resolution of 0.4 x 0.4 x 0.4 mm. The patient cohort consisted of two subgroups. In a group of ten patients with known coronary artery disease (CAD), scheduled for bypass surgery (i.e., high pretest likelihood for having significant CAD), the results of DSCT coronary angiography (CTA) and invasive quantitative catheter angiography (QCA) were compared to assess the diagnostic accuracy of DSCT in the detection of significant coronary artery stenoses (>50%). In a second group of ten patients with previous aortic valve replacement (homografts), the valve opening area of the transplanted aortic valve graft was measured by DSCT and compared with echocardiography as a standard of reference to exclude postsurgical restenosis of the valve. Of 150 coronary artery segments depicted by CT, 144 (96%) were classified as ''assessable.'' A significant CAD was known in all patients, and altogether 43 significant stenoses were present according to the results of QCA. Blinded to these results, DSCTA reached a sensitivity and specificity of 95% (41/43) and 93% (103/111), yielding a positive and negative predictive value (PPV, NPV) of 79% (31/39) and 98% (103/105), respectively. In patients with aortic valve homografts, all DSCT datasets were considered as being of diagnostic image quality concerning valve depiction. The planimetric evaluation of the CT data as compared to results of echocardiography showed a significant correlation of the results (r=0.64, p=0.0467). A high-grade valve stenosis (opening area <1.0 cm{sup 2}) could be correctly excluded by DSCT in all patients. Dual-source

  16. Probabilistic conditional reasoning: Disentangling form and content with the dual-source model.

    Science.gov (United States)

    Singmann, Henrik; Klauer, Karl Christoph; Beller, Sieghard

    2016-08-01

    The present research examines descriptive models of probabilistic conditional reasoning, that is of reasoning from uncertain conditionals with contents about which reasoners have rich background knowledge. According to our dual-source model, two types of information shape such reasoning: knowledge-based information elicited by the contents of the material and content-independent information derived from the form of inferences. Two experiments implemented manipulations that selectively influenced the model parameters for the knowledge-based information, the relative weight given to form-based versus knowledge-based information, and the parameters for the form-based information, validating the psychological interpretation of these parameters. We apply the model to classical suppression effects dissecting them into effects on background knowledge and effects on form-based processes (Exp. 3) and we use it to reanalyse previous studies manipulating reasoning instructions. In a model-comparison exercise, based on data of seven studies, the dual-source model outperformed three Bayesian competitor models. Overall, our results support the view that people make use of background knowledge in line with current Bayesian models, but they also suggest that the form of the conditional argument, irrespective of its content, plays a substantive, yet smaller, role.

  17. A stochastic inventory management model for a dual sourcing supply chain with disruptions

    Science.gov (United States)

    Iakovou, Eleftherios; Vlachos, Dimitrios; Xanthopoulos, Anastasios

    2010-03-01

    As companies continue to globalise their operations and outsource significant portion of their value chain activities, they often end up relying heavily on order replenishments from distant suppliers. The explosion in long-distance sourcing is exposing supply chains and shareholder value at ever increasing operational and disruption risks. It is well established, both in academia and in real-world business environments, that resource flexibility is an effective method for hedging against supply chain disruption risks. In this contextual framework, we propose a single period stochastic inventory decision-making model that could be employed for capturing the trade-off between inventory policies and disruption risks for an unreliable dual sourcing supply network for both the capacitated and uncapacitated cases. Through the developed model, we obtain some important managerial insights and evaluate the merit of contingency strategies in managing uncertain supply chains.

  18. Broadly tunable femtosecond mid-infrared source based on dual photonic crystal fibers.

    Science.gov (United States)

    Yao, Yuhong; Knox, Wayne H

    2013-11-04

    We report a novel scheme of generating broadly tunable femtosecond mid-IR pulses based on difference frequency mixing the outputs from dual photonic crystal fibers (PCF). With a 1.3 W, 1035 nm, 300 fs and 40 MHz Yb fiber chirped pulse amplifier as the laser source, a PCF with single zero dispersion wavelength (ZDW) at the laser wavelength is employed to spectrally broaden a portion of the laser pulses. Facilitated by self-phase modulation, its output spectrum possesses two dominant outermost peaks that can be extended to 970 nm and 1092 nm. A different PCF with two closely spaced ZDWs around the laser wavelength is used to generate the intense Stokes pulses between 1240 - 1260 nm. Frequency mixing the dual PCFs outputs in an AgGaS(2) crystal results in mid-IR pulses broadly tunable from 4.2 μm to 9 μm with a maximum average power of 640 µW at 4.5 μm, corresponding to 16 pJ of pulse energy.

  19. Ordering policies for a dual sourcing supply chain with disruption risks

    Directory of Open Access Journals (Sweden)

    Jingjing Zhu

    2013-03-01

    Full Text Available Purpose: The main purpose of this article is to explore the trade-off between ordering policies and disruption risks in a dual-sourcing network under specific (or not service level constraints, assuming that both supply channels are susceptible to disruption risks. Design/methodology/approach: Stochastic newsvendor models are presented under both the unconstrained and fill rate constraint cases. The models can be applicable for different types of disruptions related among others to the supply of raw materials, the production process, and the distribution system, as well as security breaches and natural disasters. Findings: Through the model, we obtain some important managerial insights and evaluate the value of contingency strategies in managing uncertain supply chains. Originality/value: This paper attempts to combine explicitly disruption management with risk aversion issues for a two-stage supply chain with two unreliable suppliers.

  20. New normative standards of conditional reasoning and the dual-source model.

    Science.gov (United States)

    Singmann, Henrik; Klauer, Karl Christoph; Over, David

    2014-01-01

    There has been a major shift in research on human reasoning toward Bayesian and probabilistic approaches, which has been called a new paradigm. The new paradigm sees most everyday and scientific reasoning as taking place in a context of uncertainty, and inference is from uncertain beliefs and not from arbitrary assumptions. In this manuscript we present an empirical test of normative standards in the new paradigm using a novel probabilized conditional reasoning task. Our results indicated that for everyday conditional with at least a weak causal connection between antecedent and consequent only the conditional probability of the consequent given antecedent contributes unique variance to predicting the probability of conditional, but not the probability of the conjunction, nor the probability of the material conditional. Regarding normative accounts of reasoning, we found significant evidence that participants' responses were confidence preserving (i.e., p-valid in the sense of Adams, 1998) for MP inferences, but not for MT inferences. Additionally, only for MP inferences and to a lesser degree for DA inferences did the rate of responses inside the coherence intervals defined by mental probability logic (Pfeifer and Kleiter, 2005, 2010) exceed chance levels. In contrast to the normative accounts, the dual-source model (Klauer et al., 2010) is a descriptive model. It posits that participants integrate their background knowledge (i.e., the type of information primary to the normative approaches) and their subjective probability that a conclusion is seen as warranted based on its logical form. Model fits showed that the dual-source model, which employed participants' responses to a deductive task with abstract contents to estimate the form-based component, provided as good an account of the data as a model that solely used data from the probabilized conditional reasoning task.

  1. New Normative Standards of Conditional Reasoning and the Dual-Source Model

    Directory of Open Access Journals (Sweden)

    Henrik eSingmann

    2014-04-01

    Full Text Available There has been a major shift in research on human reasoning towards Bayesian and probabilistic approaches, which has been called a new paradigm. The new paradigm sees most everyday and scientific reasoning as taking place in a context of uncertainty, and inference is from uncertain beliefs and not from arbitrary assumptions. In this manuscript we present an empirical test of normative standards in the new paradigm using a novel probabilized conditional reasoning task. Our results indicated that for everyday conditional with at least a weak causal connection between antecedent and consequent only the conditional probability of the consequent given antecedent contributes unique variance to predicting the probability of conditional, but not the probability of the conjunction, nor the probability of the material conditional. Regarding normative accounts of reasoning, we found significant evidence that participants' responses were confidence preserving (i.e., p-valid in the sense of Adams, 1998 for MP inferences, but not for MT inferences. Additionally, only for MP inferences and to a lesser degree for DA inferences did the rate of responses inside the coherence intervals defined by mental probability logic (Pfeifer & Kleiter, 2005, 2010 exceed chance levels. In contrast to the normative accounts, the dual-source model (Klauer, Beller, & Hütter, 2010 is a descriptive model. It posits that participants integrate their background knowledge (i.e., the type of information primary to the normative approaches and their subjective probability that a conclusion is seen as warranted based on its logical form. Model fits showed that the dual-source model, which employed participants' responses to a deductive task with abstract contents to estimate the form-based component, provided as good an account of the data as a model that solely used data from the probabilized conditional reasoning task.

  2. High-pitch dual-source CT coronary angiography with low volumes of contrast medium

    Energy Technology Data Exchange (ETDEWEB)

    Lembcke, Alexander; Hein, Patrick A.; Knobloch, Gesine; Durmus, Tahir; Hamm, Bernd [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); Schwenke, Carsten [SCO:SSiS - Schwenke Consulting, Berlin (Germany); Huppertz, Alexander [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); ISI - Imaging Science Institute Charite, Berlin (Germany)

    2014-01-15

    To assess the effect of lower volumes of contrast medium (CM) on image quality in high-pitch dual-source computed tomography coronary angiography (CTCA). One-hundred consecutive patients (body weight 65-85 kg, stable heart rate ≤65 bpm, cardiac index ≥2.5 L/min/m{sup 2}) referred for CTCA were prospectively enrolled. Patients were randomly assigned to one of five groups of different CM volumes (G{sub 30}, 30 mL; G{sub 40}, 40 mL; G{sub 50}, 50 mL; G{sub 60}, 60 mL; G{sub 70}, 70 mL; flow rate 5 mL/s each, iodine content 370 mg/mL). Attenuation within the proximal and distal coronary artery segments was analysed. Mean attenuation for men and women ranged from 345.0 and 399.1 HU in G{sub 30} to 478.2 and 571.8 HU in G{sub 70}. Mean attenuation values were higher in groups with higher CM volumes (P < 0.0001) and higher in women than in men (P < 0.0001). The proportions of segments with attenuation of at least 300 HU in G{sub 30}, G{sub 40}, G{sub 50}, G{sub 60} and G{sub 70} were 89 %, 95 %, 98 %, 98 % and 99 %. CM volume of 30 mL in women and 40 mL in men proved to be sufficient to guarantee attenuation of at least 300 HU. In selected patients high-pitch dual-source CTCA can be performed with CM volumes of 40 mL in men or 30 mL in women. (orig.)

  3. Using a dual isotopic approach to trace sources and mixing of sulphate in Changjiang Estuary, China

    Energy Technology Data Exchange (ETDEWEB)

    Li Siliang, E-mail: lisiliang@vip.skleg.cn [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Liu Congqiang; Patra, Sivaji [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Wang Fushun [Institute of Applied Radiation, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 201800 (China); Wang Baoli; Yue Fujun [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)

    2011-06-15

    Highlights: > Changjiang Estuary plays an important role in transportation of the water and solute. > The dual isotopic method could be used to understand sulfate biogeochemistry in estuaries. > Mixing processes should be a major factor involved in the distribution of water and sulphate. > Sulphate in the Changjiang River mainly derived from atmospheric deposition, evaporite dissolution and sulphide oxidation. - Abstract: The dual isotopic compositions of dissolved SO{sub 4}{sup 2-} in aquatic systems are commonly used to ascertain SO{sub 4}{sup 2-} sources and possible biogeochemical processes. In this study, the physical parameters, major anions and isotopic compositions of SO{sub 4}{sup 2-} in water samples from Changjiang River (Nanjin) to the East Sea in Changjiang Estuary were determined. The salinity ranged from 0 per mille to 32.3 per mille in the estuary water samples. The Cl{sup -},SO{sub 4}{sup 2-} concentrations and {delta}{sup 18}O-H{sub 2}O values followed the salinity variations from freshwater to seawater, which indicated that mixing processes might be a major factor involved in the distribution of water and solutes. The contents and isotopic compositions of SO{sub 4}{sup 2-} suggested that atmospheric deposition, evaporite dissolution and sulphide oxidation were the major sources of dissolved SO{sub 4}{sup 2-} in the freshwater of Changjiang River. In addition, the mixing model calculated by contents and isotopic compositions of SO{sub 4}{sup 2-} indicated that the mixing of freshwater and sea water was the major factor involved in SO{sub 4}{sup 2-} distribution in Changjiang Estuary. However, slightly elevated {delta}{sup 18}O-SO{sub 4} values were observed in the turbidity maximum zone, which suggested that biological processes might affect the O isotopic compositions of SO{sub 4}{sup 2-} there.

  4. Adenosine receptor neurobiology: overview.

    Science.gov (United States)

    Chen, Jiang-Fan; Lee, Chien-fei; Chern, Yijuang

    2014-01-01

    Adenosine is a naturally occurring nucleoside that is distributed ubiquitously throughout the body as a metabolic intermediary. In the brain, adenosine functions as an important upstream neuromodulator of a broad spectrum of neurotransmitters, receptors, and signaling pathways. By acting through four G-protein-coupled receptors, adenosine contributes critically to homeostasis and neuromodulatory control of a variety of normal and abnormal brain functions, ranging from synaptic plasticity, to cognition, to sleep, to motor activity to neuroinflammation, and cell death. This review begun with an overview of the gene and genome structure and the expression pattern of adenosine receptors (ARs). We feature several new developments over the past decade in our understanding of AR functions in the brain, with special focus on the identification and characterization of canonical and noncanonical signaling pathways of ARs. We provide an update on functional insights from complementary genetic-knockout and pharmacological studies on the AR control of various brain functions. We also highlight several novel and recent developments of AR neurobiology, including (i) recent breakthrough in high resolution of three-dimension structure of adenosine A2A receptors (A2ARs) in several functional status, (ii) receptor-receptor heterodimerization, (iii) AR function in glial cells, and (iv) the druggability of AR. We concluded the review with the contention that these new developments extend and strengthen the support for A1 and A2ARs in brain as therapeutic targets for neurologic and psychiatric diseases.

  5. Efficacy of a dynamic collimator for overranging dose reduction in a second- and third-generation dual source CT scanner

    NARCIS (Netherlands)

    R. Booij (Ronald); M.L. Dijkshoorn (Marcel); M. van Straten (Marcel)

    2017-01-01

    textabstractObjectives: The purpose of this study was to assess the efficacy of the renewed dynamic collimator in a third-generation dual source CT (DSCT) scanner and to determine the improvements over the second-generation scanner. Methods: Collimator efficacy is defined as the percentage overrangi

  6. Electrocortical sources related to whole-body surface translations during a single- and dual-task paradigm

    Directory of Open Access Journals (Sweden)

    Mark D Bogost

    2016-10-01

    Full Text Available Appropriate reactive motor responses are essential in maintaining upright balance. However, little is known regarding the potential location of cortical sources that are related to the onset of a perturbation during single- and dual-task paradigms. The purpose of this study was to estimate the location of cortical sources in response to a whole-body surface translation and whether diverted attention decreases the N1 event-related potential (ERP amplitude related to a postural perturbation. This study utilized high-resolution electroencephalography in conjunction with measure projection analysis from ERPs time-locked to backwards surface translation onsets to determine which cortical sources were related to whole-body postural perturbations. Subjects (n = 15 either reacted to whole-body surface translations with (dual task or without (single task performing a visual working memory task. For the single task, four domains were identified that were mainly localized within the frontal and parietal lobes and included sources from the prefrontal, premotor, primary and supplementary motor, somatosensory, and anterior cingulate cortex. Five domains were estimated for the dual task and also included sources within the frontal and parietal lobes, but the sources also shifted to other locations that included areas within the temporal and occipital lobes. Additionally, mean absolute N1 ERP amplitudes representing the activity from similar locations in both tasks were greater for the single than dual task. The present localization results highlight the importance of frontal, parietal and anterior cingulate cortical areas in reactive postural control and suggest a re-allocation or shift of cortical sources related to reactive balance control in the presence of a secondary task. Thus, this study provides novel insight into the underlying neurophysiology and contribution of cortical sources in relation to the neural control of reactive balance.

  7. Electrocortical Sources Related to Whole-Body Surface Translations during a Single- and Dual-Task Paradigm

    Science.gov (United States)

    Bogost, Mark D.; Burgos, Pablo I.; Little, C. Elaine; Woollacott, Marjorie H.; Dalton, Brian H.

    2016-01-01

    Appropriate reactive motor responses are essential in maintaining upright balance. However, little is known regarding the potential location of cortical sources that are related to the onset of a perturbation during single- and dual-task paradigms. The purpose of this study was to estimate the location of cortical sources in response to a whole-body surface translation and whether diverted attention decreases the N1 event-related potential (ERP) amplitude related to a postural perturbation. This study utilized high-resolution electroencephalography in conjunction with measure projection analysis from ERPs time-locked to backwards surface translation onsets to determine which cortical sources were related to whole-body postural perturbations. Subjects (n = 15) either reacted to whole-body surface translations with (dual task) or without (single task) performing a visual working memory task. For the single task, four domains were identified that were mainly localized within the frontal and parietal lobes and included sources from the prefrontal, premotor, primary and supplementary motor, somatosensory and anterior cingulate cortex. Five domains were estimated for the dual task and also included sources within the frontal and parietal lobes, but the sources also shifted to other locations that included areas within the temporal and occipital lobes. Additionally, mean absolute N1 ERP amplitudes representing the activity from similar locations in both tasks were greater for the single than dual task. The present localization results highlight the importance of frontal, parietal and anterior cingulate cortical areas in reactive postural control and suggest a re-allocation or shift of cortical sources related to reactive balance control in the presence of a secondary task. Thus, this study provides novel insight into the underlying neurophysiology and contribution of cortical sources in relation to the neural control of reactive balance.

  8. Dual diagnosis, as described by those who experience the disorder: using the Internet as a source of data.

    Science.gov (United States)

    Edward, Karen-Leigh; Robins, Alan

    2012-12-01

    The complexity of providing treatment for people with dual diagnosis is well recognized. For the purpose of this paper, the World Health Organization definition of dual diagnosis was used; that is, a person diagnosed with an alcohol or drug use problem in addition to mental illness. This research explored the personal narratives of those who experience dual diagnosis using the Internet as a data source. An important consideration in using the Internet as a data source was that Web forums can offer a sense of anonymity, allowing people to share very detailed and personal information, and providing a rich source of qualitative data. The results produced five emergent themes: spiralling out of control - again!, getting help and giving support, treating both the addiction and mental illness, having meaning and being active, and being honest with self and others. The results indicate that individuals who experience dual diagnosis are often left to navigate their personal treatment requirements across two diverse systems, and were generally not satisfied with the conflictual advice received across these two systems (i.e. alcohol and other drug and mental health services). This study has produced valuable insights related to consumer-perceived service barriers and enablers.

  9. Sources and transformations of nitrate from streams draining varying land uses: Evidence from dual isotope analysis

    Science.gov (United States)

    Burns, Douglas A.; Boyer, E.W.; Elliott, E.M.; Kendall, C.

    2009-01-01

    Knowledge of key sources and biogeochemical processes that affect the transport of nitrate (NO3-) in streams can inform watershed management strategies for controlling downstream eutrophication. We applied dual isotope analysis of NO3- to determine the dominant sources and processes that affect NO3- concentrations in six stream/river watersheds of different land uses. Samples were collected monthly at a range of flow conditions for 15 mo during 2004-05 and analyzed for NO3- concentrations, ?? 15NNO3, and ??18ONO3. Samples from two forested watersheds indicated that NO3- derived from nitrification was dominant at baseflow. A watershed dominated by suburban land use had three ??18ONO3 values greater than +25???, indicating a large direct contribution of atmospheric NO 3- transported to the stream during some high flows. Two watersheds with large proportions of agricultural land use had many ??15NNO3 values greater than +9???, suggesting an animal waste source consistent with regional dairy farming practices. These data showed a linear seasonal pattern with a ??18O NO3:??15NNO3 of 1:2, consistent with seasonally varying denitrification that peaked in late summer to early fall with the warmest temperatures and lowest annual streamflow. The large range of ?? 15NNO3 values (10???) indicates that NO 3- supply was likely not limiting the rate of denitrification, consistent with ground water and/or in-stream denitrification. Mixing of two or more distinct sources may have affected the seasonal isotope patterns observed in these two agricultural streams. In a mixed land use watershed of large drainage area, none of the source and process patterns observed in the small streams were evident. These results emphasize that observations at watersheds of a few to a few hundred km2 may be necessary to adequately quantify the relative roles of various NO 3- transport and process patterns that contribute to streamflow in large basins. Copyright ?? 2009 by the American Society of

  10. Adenosine and sleep

    Energy Technology Data Exchange (ETDEWEB)

    Yanik, G.M. Jr.

    1987-01-01

    Behavioral and biochemical approaches have been used to determine the relative contribution of endogenous adenosine and adenosine receptors to the sleep-wake cycle in the rat. Adenosine concentrations in specific areas of the rat brain were not affected by 24 hours of total sleep deprivation, or by 24 or 48 hours of REM sleep deprivation. In order to assess the effect of REM sleep deprivation on adenosine A/sub 1/ receptors, /sup 3/H-L-PIA binding was measured. The Bmax values for /sup 3/H-L-PIA binding to membrane preparations of the cortices and corpus striata from 48 hour REM sleep-deprived animals were increased 14.8% and 23%, respectively. These increases were not maintained following the cessation of sleep deprivation and recovered within 2 hours. The results of a 96 hour REM deprivation experiment were similar to those of the 48 hour REM sleep deprivation experiment. However, these increases were not evident in similar structures taken from stress control animals, and conclusively demonstrated that the changes in /sup 3/H-L-PIA binding resulted from REM sleep deprivation and not from stress.

  11. Evaluation of global left ventricular function assessment by dual-source computed tomography compared with MRI

    Energy Technology Data Exchange (ETDEWEB)

    Vleuten, Pieter A. van der; Tio, Rene A.; Zijlstra, Felix [University Medical Centre Groningen, Thoraxcenter, Department of Cardiology, P.O. Box 30001, Groningen (Netherlands); Jonge, Gonda J. de; Lubbers, Daniel D.; Willems, Tineke P.; Oudkerk, Matthijs [University Medical Centre Groningen, Department of Radiology, Groningen (Netherlands)

    2009-02-15

    Left ventricular (LV) function assessment by dual-source computed tomography (DSCT) was compared with the reference standard method using magnetic resonance imaging (MRI). Accurate assessment of LV function is essential for the prediction of prognosis in cardiac disease. Thirty-four patients undergoing DSCT examination of the heart for various clinical indications underwent MRI after DSCT. Short-axis cine images were reconstructed from the DSCT datasets and were analyzed using a dedicated post-processing software-tool to generate global left ventricular function parameters. Five DSCT datasets were considered to be of insufficient image quality. DSCT showed a small overestimation of end-diastolic and end-systolic volumes of 11.0 ml and 3.5 ml, nrespectively. Myocardial mass assessed by DSCT showed an average underestimation of 0.2 g. DSCT showed a small overestimation of LV ejection fraction (LVEF) of 0.4%-point with a Bland-Altman interval of [-8.67 (0.40) 9.48]. Global LV functional parameters calculated from DSCT datasets acquired in daily clinical practice correlated well with MRI and may be considered interchangeable. However, visual assessment of the image quality of the short-axis cine slices should be performed to detect any artifacts in the DSCT data which could influence accuracy. (orig.)

  12. Visualization of anomalous coronary arteries on dual-source computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jonge, G.J. de; Ooijen, P.M.A. van; Dikkers, R.; Willems, T.P.; Oudkerk, M. [University Medical Center Groningen, University of Groningen, Department of Radiology, Hanzeplein 1, P.O. Box 30.001, Groningen (Netherlands); Piers, L.H.; Tio, R.A.; Heuvel, A.F.M. van den; Zijlstra, F. [University Medical Center Groningen, University of Groningen, Department of Cardiology, Groningen (Netherlands)

    2008-11-15

    The purpose of this study is to assess the capability of dual-source computed tomography (DSCT) in evaluating coronary artery anomalies. Early detection and evaluation of coronary artery anomalies is essential because of their potential association with myocardial ischemia and sudden death. In 16 patients (12 men, mean age 50 {+-} 14 years), anomalous coronary arteries were detected on contrast-enhanced DSCT in a patient cohort of 230 individuals (incidence of 7%). Six different types of anomalies were diagnosed (three fistula, four anomalies of the circumflex artery, four anomalous right coronary arteries, three anomalies of the left coronary artery, one absent left main coronary artery, and one left coronary artery arising from the pulmonary trunk). Of the 16 patients, 10 also underwent conventional coronary angiography (CAG). Retrospective evaluation of the CAGs by an experienced interventional cardiologist resulted in a precise diagnosis in 50% of patients. With DSCT, sufficient image quality and exact visualization of the aberrant anatomy were achieved in all patients. Therefore, DSCT seems to be an accurate diagnostic tool for examining the precise origin, course, and shape of aberrant coronary arteries. (orig.)

  13. Dose heterogeneity correction for low-energy brachytherapy sources using dual-energy CT images.

    Science.gov (United States)

    Mashouf, S; Lechtman, E; Lai, P; Keller, B M; Karotki, A; Beachey, D J; Pignol, J P

    2014-09-21

    Permanent seed implant brachytherapy is currently used for adjuvant radiotherapy of early stage prostate and breast cancer patients. The current standard for calculation of dose around brachytherapy sources is based on the AAPM TG-43 formalism, which generates the dose in a homogeneous water medium. Recently, AAPM TG-186 emphasized the importance of accounting for tissue heterogeneities. We have previously reported on a methodology where the absorbed dose in tissue can be obtained by multiplying the dose, calculated by the TG-43 formalism, by an inhomogeneity correction factor (ICF). In this work we make use of dual energy CT (DECT) images to extract ICF parameters. The advantage of DECT over conventional CT is that it eliminates the need for tissue segmentation as well as assignment of population based atomic compositions. DECT images of a heterogeneous phantom were acquired and the dose was calculated using both TG-43 and TG-43 [Formula: see text] formalisms. The results were compared to experimental measurements using Gafchromic films in the mid-plane of the phantom. For a seed implant configuration of 8 seeds spaced 1.5 cm apart in a cubic structure, the gamma passing score for 2%/2 mm criteria improved from 40.8% to 90.5% when ICF was applied to TG-43 dose distributions.

  14. Dual-source computed tomography in patients with acute chest pain: feasibility and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Schertler, Thomas; Scheffel, Hans; Frauenfelder, Thomas; Desbiolles, Lotus; Leschka, Sebastian; Stolzmann, Paul; Marincek, Borut; Alkadhi, Hatem [University Hospital Zurich, Department of Medical Radiology, Institute of Diagnostic Radiology, Zurich (Switzerland); Seifert, Burkhardt [University of Zurich, Department of Biostatistics, Zurich (Switzerland); Flohr, Thomas G. [Computed Tomography CTE PA, Siemens Medical Solutions, Forchheim (Germany)

    2007-12-15

    The aim of this study was to determine the feasibility and image quality of dual-source computed tomography angiography (DSCTA) in patients with acute chest pain for the assessment of the lung, thoracic aorta, and for pulmonary and coronary arteries. Sixty consecutive patients (32 female, 28 male, mean age 58.1{+-}16.3 years) with acute chest pain underwent contrast-enhanced electrocardiography-gated DSCTA without prior beta-blocker administration. Vessel attenuation of different thoracic vascular territories was measured, and image quality was semi-quantitatively analyzed by two independent readers. Image quality of the thoracic aorta was diagnostic in all 60 patients, image quality of pulmonary arteries was diagnostic in 59, and image quality of coronary arteries was diagnostic in 58 patients. Pairwise intraindividual comparisons of attenuation values were small and ranged between 1{+-}6 HU comparing right and left coronary artery and 56{+-}9 HU comparing the pulmonary trunk and left ventricle. Mean attenuation was 291{+-}65 HU in the ascending aorta, 334{+-}93 HU in the pulmonary trunk, and 285{+-}66 HU and 268{+-}67 HU in the right and left coronary artery, respectively. DSCTA is feasible and provides diagnostic image quality of the thoracic aorta, pulmonary and coronary arteries in patients with acute chest pain. (orig.)

  15. Dual-Source Precursor Approach for Highly Efficient Inverted Planar Heterojunction Perovskite Solar Cells.

    Science.gov (United States)

    Luo, Deying; Zhao, Lichen; Wu, Jiang; Hu, Qin; Zhang, Yifei; Xu, Zhaojian; Liu, Yi; Liu, Tanghao; Chen, Ke; Yang, Wenqiang; Zhang, Wei; Zhu, Rui; Gong, Qihuang

    2017-03-15

    The highest efficiencies reported for perovskite solar cells so far have been obtained mainly with methylammonium and formamidinium mixed cations. Currently, high-quality mixed-cation perovskite thin films are normally made by use of antisolvent protocols. However, the widely used "antisolvent"-assisted fabrication route suffers from challenges such as poor device reproducibility, toxic and hazardous organic solvent, and incompatibility with scalable fabrication process. Here, a simple dual-source precursor approach is developed to fabricate high-quality and mirror-like mixed-cation perovskite thin films without involving additional antisolvent process. By integrating the perovskite films into the planar heterojunction solar cells, a power conversion efficiency of 20.15% is achieved with negligible current density-voltage hysteresis. A stabilized power output approaching 20% is obtained at the maximum power point. These results shed light on fabricating highly efficient perovskite solar cells via a simple process, and pave the way for solar cell fabrication via scalable methods in the near future.

  16. Dose heterogeneity correction for low-energy brachytherapy sources using dual-energy CT images

    Science.gov (United States)

    Mashouf, S.; Lechtman, E.; Lai, P.; Keller, B. M.; Karotki, A.; Beachey, D. J.; Pignol, J. P.

    2014-09-01

    Permanent seed implant brachytherapy is currently used for adjuvant radiotherapy of early stage prostate and breast cancer patients. The current standard for calculation of dose around brachytherapy sources is based on the AAPM TG-43 formalism, which generates the dose in a homogeneous water medium. Recently, AAPM TG-186 emphasized the importance of accounting for tissue heterogeneities. We have previously reported on a methodology where the absorbed dose in tissue can be obtained by multiplying the dose, calculated by the TG-43 formalism, by an inhomogeneity correction factor (ICF). In this work we make use of dual energy CT (DECT) images to extract ICF parameters. The advantage of DECT over conventional CT is that it eliminates the need for tissue segmentation as well as assignment of population based atomic compositions. DECT images of a heterogeneous phantom were acquired and the dose was calculated using both TG-43 and TG-43 × \\text{ICF} formalisms. The results were compared to experimental measurements using Gafchromic films in the mid-plane of the phantom. For a seed implant configuration of 8 seeds spaced 1.5 cm apart in a cubic structure, the gamma passing score for 2%/2 mm criteria improved from 40.8% to 90.5% when ICF was applied to TG-43 dose distributions.

  17. Adaptive optics OCT using 1060nm swept source and dual deformable lenses for human retinal imaging

    Science.gov (United States)

    Jian, Yifan; Lee, Sujin; Cua, Michelle; Miao, Dongkai; Bonora, Stefano; Zawadzki, Robert J.; Sarunic, Marinko V.

    2016-03-01

    Adaptive optics concepts have been applied to the advancement of biological imaging and microscopy. In particular, AO has also been very successfully applied to cellular resolution imaging of the retina, enabling visualization of the characteristic mosaic patterns of the outer retinal layers using flood illumination fundus photography, Scanning Laser Ophthalmoscopy (SLO), and Optical Coherence Tomography (OCT). Despite the high quality of the in vivo images, there has been a limited uptake of AO imaging into the clinical environment. The high resolution afforded by AO comes at the price of limited field of view and specialized equipment. The implementation of a typical adaptive optics imaging system results in a relatively large and complex optical setup. The wavefront measurement is commonly performed using a Hartmann-Shack Wavefront Sensor (HS-WFS) placed at an image plane that is optically conjugated to the eye's pupil. The deformable mirror is also placed at a conjugate plane, relaying the wavefront corrections to the pupil. Due to the sensitivity of the HS-WFS to back-reflections, the imaging system is commonly constructed from spherical mirrors. In this project, we present a novel adaptive optics OCT retinal imaging system with significant potential to overcome many of the barriers to integration with a clinical environment. We describe in detail the implementation of a compact lens based wavefront sensorless adaptive optics (WSAO) 1060nm swept source OCT human retinal imaging system with dual deformable lenses, and present retinal images acquired in vivo from research volunteers.

  18. Noise-tolerance analysis for detection and reconstruction of absorbing inhomogeneities with diffuse optical tomography using single- and phase-correlated dual-source schemes

    Science.gov (United States)

    Kanmani, B.; Vasu, R. M.

    2007-03-01

    An iterative reconstruction procedure is used to invert intensity data from both single- and phase-correlated dual-source illuminations for absorption inhomogeneities. The Jacobian for the dual source is constructed by an algebraic addition of the Jacobians estimated for the two sources separately. By numerical simulations, it is shown that the dual-source scheme performs superior to the single-source system in regard to (i) noise tolerance in data and (ii) ability to reconstruct smaller and lower contrast objects. The quality of reconstructions from single-source data, as indicated by mean-square error at convergence, is markedly poorer compared to their dual-source counterpart, when noise in data was in excess of 2%. With fixed contrast and decreasing inhomogeneity diameter, our simulations showed that, for diameters below 7 mm, the dual-source scheme has a higher percentage contrast recovery compared to the single-source scheme. Similarly, the dual-source scheme reconstructs to a higher percentage contrast recovery from lower contrast inhomogeneity, in comparison to the single-source scheme.

  19. Dual-source dual-energy CT angiography with virtual non-enhanced images and iodine map for active gastrointestinal bleeding: Image quality, radiation dose and diagnostic performance

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hao, E-mail: sunhao_robert@126.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Hou, Xin-Yi, E-mail: hxy_pumc@126.com [Department of Radiology, Beijing Tiantan Hospital, Capital Medical University, Beijing (China); Xue, Hua-Dan, E-mail: bjdanna95@hotmail.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Li, Xiao-Guang, E-mail: xglee88@126.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Jin, Zheng-Yu, E-mail: zhengyu_jin@126.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Qian, Jia-Ming, E-mail: qjiaming57@gmail.com [Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Yu, Jian-Chun, E-mail: yu-jch@163.com [Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Zhu, Hua-Dong, E-mail: huadongzhu@hotmail.com [Department of Emergency, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China)

    2015-05-15

    Highlights: • GIB is a common gastrointestinal emergency with a high mortality rate. • Detection and localization of GIB source are important for imaging modality. • DSDECTA using a dual-phase scan protocol is clinically feasible. • DSDECTA with VNE and iodine map images can diagnose the active GIB source accurately. • DSDECTA can reduce radiation dose compared with conventional CT examination in GIB. - Abstract: Objectives: To evaluate the clinical feasibility of dual-source dual-energy CT angiography (DSDECTA) with virtual non-enhanced images and iodine map for active gastrointestinal bleeding (GIB). Methods: From June 2010 to December 2012, 112 consecutive patients with clinical signs of active GIB underwent DSDECTA with true non-enhanced (TNE), arterial phase with single-source mode, and portal-venous phase with dual-energy mode (100 kVp/230 mAs and Sn 140 kVp/178 mAs). Virtual non-enhanced CT (VNE) image sets and iodine map were reformatted from ‘Liver VNC’ software. The mean CT number, noise, signal to noise ratio (SNR), image quality and radiation dose were compared between TNE and VNE image sets. Two radiologists, blinded to clinical data, interpreted images from DSDECTA with TNE (protocol 1), and DSDECTA with VNE and iodine map (protocol 2) respectively, with discordant interpretation resolved by consensus. The standards of reference included digital subtraction angiography, endoscopy, surgery, or final pathology reports. Receiver–operating characteristic (ROC) analysis was undertaken and the area under the curve (AUC) calculated for CT protocols 1 and 2, respectively. Results: There was no significant difference in mean CT numbers of all organs (including liver, pancreas, spleen, kidney, abdominal aorta, and psoas muscle) (P > 0.05). Lower noise and higher SNR were found on VNE images than TNE images (P < 0.05). Image quality of VNE was lower than that of TNE without significant difference (P > 0.05). The active GIB source was identified

  20. Virtual monochromatic imaging in dual-source and dual-energy CT for visualization of acute ischemic stroke

    CERN Document Server

    Hara, Hidetake; Matsuzawa, Hiroki; Inoue, Toshiyuki; Abe, Shinji; Satoh, Hitoshi; Nakajima, Yasuo

    2015-01-01

    We have recently developed a phantom that simulates acute ischemic stroke. We attempted to visualize acute-stage cerebral infarction by applying virtual monochromatic images to this phantom using dual-energy CT (DECT). Virtual monochromatic images were created using DECT from 40 to 100 keV at every 10 keV and from 60 to 80 keV at every 1 keV, under three energy conditions of tube voltages with thin (Sn) filters. Calculation of the CNR values allowed us to evaluate the visualization of acute-stage cerebral infarction. The CNR value of a virtual monochromatic image was the highest at 68 keV under 80 kV / Sn 140 kV, at 72 keV under 100 kV / Sn 140 kV, and at 67 keV under 140 kV / 80 kV. The CNR values of virtual monochromatic images between 65 and 75 keV were significantly higher than those obtained for all other created energy images. Therefore, optimal conditions for visualizing acute ischemic stroke were achievable.

  1. High-pitch dual-source CT angiography of the whole aorta without ECG synchronisation: Initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Beeres, Martin; Schell, Boris; Mastragelopoulos, Aristidis; Kerl, Josef Matthias; Gruber-Rouh, Tatjana; Lee, Clara; Siebenhandl, Petra; Bodelle, Boris; Zangos, Stephan; Vogl, Thomas J.; Jacobi, Volkmar; Bauer, Ralf W. [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Herrmann, Eva [Clinic of the Goethe University, Department of Biostatistics, Frankfurt (Germany)

    2012-01-15

    To investigate the feasibility, image quality and radiation dose for high-pitch dual-source CT angiography (CTA) of the whole aorta without ECG synchronisation. Each group of 40 patients underwent CTA either on a 16-slice (group 1) or dual-source CT device with conventional single-source (group 2) or high-pitch mode with a pitch of 3.0 (group 3). The presence of motion or stair-step artefacts of the thoracic aorta was independently assessed by two readers. Subjective and objective scoring of motion and artefacts were significantly reduced in the high-pitch examination protocol (p < 0.05). The imaging length was not significantly different, but the imaging time was significantly (p < 0.001) shorter in the high-pitch group (12.2 vs. 7.4 vs. 1.7 s for groups 1, 2 and 3). The ascending aorta and the coronary ostia were reliably evaluable in all patients of group 3 without motion artefacts as well. High-pitch dual-source CT angiography of the whole aorta is feasible in unselected patients. As a significant advantage over regular pitch protocols, motion-free imaging of the aorta is possible without ECG synchronisation. Thus, this CT mode bears potential to become a standard CT protocol before trans-catheter aortic valve implantation (TAVI). (orig.)

  2. Dual-source CT coronary angiography in patients with atrial fibrillation: Comparison with single-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yining [Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China)], E-mail: yiningpumc@hotmail.com; Zhang Zhuhua [Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China)], E-mail: yiningpumc@sina.com; Kong Lingyan [Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China)], E-mail: klyan78@hotmail.com; Song Lan [Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China)], E-mail: sallysonglan@sina.com; Merges, Reto D. [CT Research Collaboration, Siemens Ltd. (China)], E-mail: reto.merges@siemens.com; Chen Jiuhong [CT Research Collaboration, Siemens Ltd. (China)], E-mail: jiuhong.chen@siemens.com; Jin Zhengyu [Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China)], E-mail: jin_zhengyu@sina.com

    2008-12-15

    Objective: To evaluate the performance of dual-source computed tomography (DSCT) for the visualization of the coronary arteries in a population with atrial fibrillation (AF) compared to single-source CT (SSCT) and to explore the impact of patients' heart rate (HR) on image quality (IQ) and reconstruction timing. Methods: Thirty consecutive patients (11 male, 19 female; 69.0 {+-} 9.2 years old) with suspected coronary artery disease and permanent AF were examined on a DSCT scanner (120 kV, 400 mAs/rot, 0.33 s rotation time, 64 x 0.6 mm collimation, pitch 0.20-0.28, Siemens Somatom Definition). Patients were divided into two groups: low and medium HR group (HR {<=} 80 bpm, n = 14) and high HR group (HR > 80 bpm, n = 16). Five of the patients also underwent conventional coronary angiography (CAG). The raw data from both tube detector arrays were reconstructed as DSCT data using a routine algorithm (temporal resolution of 83 ms). The raw data from one tube detector array was reconstructed separately on the same system using a routine single source algorithm (temporal resolution of 83-165 ms) and defined as virtual SSCT data. Image quality was assessed using a four-point grading scale from excellent (1) to non-assessable (4). Results: IQ of the DSCT data was significantly better than that of the virtual SSCT data (mean score 1.33 {+-} 0.61 vs. 1.80 {+-} 1.02; Z = -8.755, P = 0.000). 98.6% of the segments shown in DSCT were diagnostic, compared with 89.9% of the segments in virtual SSCT, {chi}{sup 2} = 32.595, P = 0.000. In DSCT group, IQ of low HR group was also better than that of high HR group, although the difference was not as big (mean score 1.25 {+-} 0.52 vs. 1.38 {+-} 0.66; Z = -2.227, P = 0.026). The mean HR of low HR group and high HR group were 67.4 {+-} 8.5 beats per minute (bpm) and 94.2 {+-} 8.8 bpm (t = -8.499, P = 0.000). The range of the variation of HR was higher in high HR group than in low HR group (mean difference between maximum and minimum HR

  3. Efficacy of a dynamic collimator for overranging dose reduction in a second- and third-generation dual source CT scanner

    OpenAIRE

    Booij, Ronald; Dijkshoorn, Marcel; Straten, Marcel

    2017-01-01

    textabstractObjectives: The purpose of this study was to assess the efficacy of the renewed dynamic collimator in a third-generation dual source CT (DSCT) scanner and to determine the improvements over the second-generation scanner. Methods: Collimator efficacy is defined as the percentage overranging dose in terms of dose–length product (DLP) that is blocked by the dynamic collimator relative to the total overranging dose in case of a static collimator. Efficacy was assessed at various pitch...

  4. 双源CT临床应用新进展%Dual-source CT clinical application of new progress

    Institute of Scientific and Technical Information of China (English)

    黄远彬

    2014-01-01

    双源CT进行2种不同能量的X线同步扫描,可获得双能量图像,具有成像速度快,辐射剂量低,图像质量高的优点。双源CT进行冠状动脉成像,图像质量不再受患者心率过快、不规则以及屏气困难的影响,能获得可靠的冠状动脉图像,是目前无创性左室功能检查评价最具价值的检查方法之一。双源CT扫描时间缩短辐射剂量降低,有效克服部分患者移动伪影及呼吸伪影,适用于儿童患者及躁动患者的检查,为急性胸痛患者快速诊断提供安全有效手段。双源CT双能量虚拟平扫在头部、胸部、腹部疾病检查中已得到良好运用。双源CT在两种不同能量状态下的数据采集可对物质成分进行定性分析,拓宽了CT的应用范围,具有较好临床价值。%Dual source CT for 2 different energy X-ray scanning, can obtain the dual energy images, has fast imaging speed, low radiation dose, the advantages of high image quality. Dual source CT coronary artery imaging, image quality is not affected by the patient’s heart rate too fast, irregular and breath dififcult, can obtain the coronary artery image reliable;it is one of the current inspection method without evaluation and examination of the left ventricular function most value. Dual source CT scan can reduce the time of radiation dose, effectively overcome some patients moving artifact and respiratory artifacts, suitable for children patients and agitation of patients, to provide safe, effective method for the rapid diagnosis and emergency classiifcation of patients with acute chest pain. Dual energy CT virtual scan has been well used in the head, chest, abdominal disease examination. Dual source CT for qualitative analysis of components in two different energy state of the data acquisition, and widen the application range of CT, with good clinical application.

  5. Performance of turbo high-pitch dual-source CT for coronary CT angiography: first ex vivo and patient experience

    Energy Technology Data Exchange (ETDEWEB)

    Morsbach, Fabian; Gordic, Sonja; Husarik, Daniela; Frauenfelder, Thomas; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Desbiolles, Lotus; Leschka, Sebastian [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Kantonsspital St. Gallen, Divison of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Schmidt, Bernhard; Allmendinger, Thomas [Siemens AG, Healthcare Sector, Forchheim (Germany); Wildermuth, Simon [Kantonsspital St. Gallen, Divison of Radiology and Nuclear Medicine, St. Gallen (Switzerland)

    2014-08-15

    To evaluate image quality, maximal heart rate allowing for diagnostic imaging, and radiation dose of turbo high-pitch dual-source coronary computed tomographic angiography (CCTA). First, a cardiac motion phantom simulating heart rates (HRs) from 60-90 bpm in 5-bpm steps was examined on a third-generation dual-source 192-slice CT (prospective ECG-triggering, pitch 3.2; rotation time, 250 ms). Subjective image quality regarding the presence of motion artefacts was interpreted by two readers on a four-point scale (1, excellent; 4, non-diagnostic). Objective image quality was assessed by calculating distortion vectors. Thereafter, 20 consecutive patients (median, 50 years) undergoing clinically indicated CCTA were included. In the phantom study, image quality was rated diagnostic up to the HR75 bpm, with object distortion being 1 mm or less. Distortion increased above 1 mm at HR of 80-90 bpm. Patients had a mean HR of 66 bpm (47-78 bpm). Coronary segments were of diagnostic image quality for all patients with HR up to 73 bpm. Average effective radiation dose in patients was 0.6 ± 0.3 mSv. Our combined phantom and patient study indicates that CCTA with turbo high-pitch third-generation dual-source 192-slice CT can be performed at HR up to 75 bpm while maintaining diagnostic image quality, being associated with an average radiation dose of 0.6 mSv. (orig.)

  6. Intensity distribution and impact of scatter for dual-source CT

    Science.gov (United States)

    Kyriakou, Yiannis; Kalender, Willi A.

    2007-12-01

    Apart from forward scatter, which is given for all CT scanners, dual-source CT (DSCT) is also affected by cross-scatter photons from the second tube-detector system arranged at 90°. We investigated the magnitude and distribution of scatter for DSCT and its impact on image quality. Simulations and measurements of homogeneous and anthropomorphic phantoms were conducted for a DSCT scanner (SOMATOM Definition, Siemens Medical Solutions, Forchheim, Germany) at tube voltages of 80 and 120 kV. The simulations of forward scatter were carried out using combined analytical and Monte Carlo simulation methods for a collimation of 19.2 mm for both tube-detector systems. Measurements of cross scatter were performed by switching one tube off, still reading out the corresponding detector. The relative scatter fractions and the distribution of cross scatter were registered for various imaging conditions. Additionally, a detailed noise analysis with respect to the correction of cross-scatter artifacts is provided to evaluate the performance of correction algorithms. The forward-scatter fraction increased with increasing phantom diameter from 0.02 up to 0.11 for PMMA phantoms of 80 to 400 mm diameter. For cross scatter, the mean intensity was equivalent to forward scatter for small phantoms but was larger for increased phantom size and resulted in severe artifacts in the reconstructed images. The outer dimensions and shape of the object are decisive for the cross-scatter intensity distribution whereas the influence of the degree of inhomogeneity of the respective phantom appears to be negligible. Scatter correction suppressed cross-scatter artifacts but increased noise as a function of the cross-scatter fraction. The magnitude of scatter is not negligible for DSCT systems and dedicated corrections are necessary for the assurance of unimpaired image quality.

  7. Coronary lesion complexity assessed by SYNTAX score in 256-slice dual-source MDCT angiography

    Science.gov (United States)

    Yüceler, Zeyneb; Kantarcı, Mecit; Tanboğa, İbrahim Halil; Sade, Recep; Kızrak, Yeşim; Pirimoğlu, Berhan; Bayraktutan, Ümmügülsüm; Oğul, Hayri; Aksakal, Enbiya

    2016-01-01

    PURPOSE The SYNTAX Score (SS) has an important role in grading the complexity of coronary artery disease (CAD) in patients undergoing revascularization. Noninvasive determination of SS prior to invasive coronary angiography (ICA) might optimize patient management. We aimed to evaluate the agreement between ICA and multidetector computed tomography (MDCT) while testing the diagnostic effectiveness of SS-MDCT. METHODS Our study included 108 consecutive patients who underwent both MDCT angiography with a 256-slice dual-source MDCT system and ICA within 14±3 days. SS was calculated for both ICA and MDCT coronary angiography. Spearman’s rank correlation coefficient was used to evaluate the association of SS-MDCT with SS-ICA, and Bland-Altman analysis was performed. RESULTS The degree of agreement between SS-ICA and SS-MDCT was moderate. The mean SS-MDCT was 14.5, whereas the mean SS-ICA was 15.9. After dividing SS into three groups (high [≥33], intermediate [23–32], and low [≤22] subgroups), agreement analysis was repeated. There was a significant correlation between SS-MDCT and SS-ICA in the low SS group (r=0.63, P = 0.043) but no significant correlation in the high SS group (r=0.036, P = 0.677). The inter-test agreement analysis showed at least moderate agreement, whereas thrombotic lesions and the type of bifurcation lesion showed fair agreement. CONCLUSION The calculation of SS-MDCT by adapting SS-ICA parameters achieved nearly the same degree of precision as SS-ICA and was better than SS-ICA, especially in the low SS group. PMID:27328718

  8. Quantitative assessment of pure aortic valve regurgitation with dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z., E-mail: lzlcd01@126.com [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Huang, L.; Chen, X.; Xia, C.; Yuan, Y.; Shuai, T. [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China)

    2012-07-15

    Aim: To assess the severity of pure aortic regurgitation by measuring regurgitation volumes (RV) and fractions (RF) with dual-source computed tomography (DSCT) as compared to magnetic resonance imaging (MRI) and echocardiography. Materials and methods: Thirty-eight patients (15 men, 23 women; mean age 46 {+-} 11 years) with isolated aortic valve regurgitation underwent retrospectively electrocardiogram (ECG)-gated DSCT, echocardiography, and MRI. Stroke volumes of the left and right ventricles were measured at DSCT and MRI. Thus, RVs and RFs were calculated and compared. The agreement between DSCT and MRI was tested by intraclass correlation coefficient and Bland-Altman analyses. Spearman's rank order correlation and weighted {kappa} tests were used for testing correlations of AR severity between DSCT results and corresponding echocardiographic grades. Results: The RV and RF measured by DSCT were not significantly different from those measured using MRI (p = 0.71 and 0.79). DSCT correlated well with MRI for the measurement of RV (r{sub I} = 0.86, p<0.001) and calculation of the RF (r{sub I} =0.90, p<0.001). Good agreement between the techniques was obtained by using Bland-Altman analyses. The severity of regurgitation estimated by echocardiography correlated well with DSCT (r{sub s} = 0.95, p<0.001) and MRI (r{sub s} = 0.95, p<0.001). Inter-technique agreement between DSCT and two-dimensional transthoracic echocardiography (2DTTE) regarding the grading of the severity of AR was excellent ({kappa} = 0.90), and good agreement was also obtained between MRI and 2DTTE assessments of the severity of AR ({kappa} = 0.87). Conclusion: DSCT using a volume approach can be used to quantitatively determine the severity of pure aortic regurgitation when compared with MRI and echocardiography.

  9. Diagnostic accuracy of dual-source CT coronary angiography in patients with atrial fibrillation: Meta analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Gang, E-mail: cjr.sungang@vip.163.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Li, Min [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jiang, Zhi-wei [Department of Health Statistics, School of Public Health, Fourth Military Medical University, No. 169, Changle West Road, Xi’an, Shaanxi 710032 (China); Xu, Lin [Department of Medical Cardiology, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Peng, Zhao-hui; Ding, Juan; Li, Li [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jin, Zhi-tao [Department of Cardiology, General Hospital of the Second Artillery, Beijing 100088 (China)

    2013-10-01

    Rationale and objective: To synthesize the available data to underscore the diagnostic accuracy of dual-source CT (DSCT) coronary angiography in patients with atrial fibrillation (AF). Materials and methods: We searched in the electronic databases of PubMed for all published studies that examined patients with AF using DSCT. We used an exact binomial rendition of the bivariate mixed-effects regression model to synthesize the diagnostic data. Results: The positive and negative likelihood ratios (LRs) at the patient level were 6.0 (CI, 3.6–10.1) and 0.03(CI, 0.004–0.2), respectively. The negative predictive values higher than 90% were available for a CAD prevalence <78%. The pooled vessel- and segment-level estimates showed higher positive and negative LRs than the patient-level estimates (15.3 [CI, 9.8–23.9] and 0.1 [CI, 0.07–0.3]; 25.1 [CI, 10.8–58.5] and 0.2 [CI, 0.2–0.3], respectively). No statistically significant heterogeneity between studies and publication bias were found at the patient level estimate. A sensitivity analysis showed that no study influenced the pooled results larger than 0.02. Conclusions: Cardiac angiography with DSCT can be applied as an imaging test for ruling out CAD in patient with AF. However, DSCT angiography may be not an effective tool for risk stratification for the high negative LR at the artery and segment levels.

  10. Silicon photonic integrated circuit swept-source optical coherence tomography receiver with dual polarization, dual balanced, in-phase and quadrature detection.

    Science.gov (United States)

    Wang, Zhao; Lee, Hsiang-Chieh; Vermeulen, Diedrik; Chen, Long; Nielsen, Torben; Park, Seo Yeon; Ghaemi, Allan; Swanson, Eric; Doerr, Chris; Fujimoto, James

    2015-07-01

    Optical coherence tomography (OCT) is a widely used three-dimensional (3D) optical imaging method with many biomedical and non-medical applications. Miniaturization, cost reduction, and increased functionality of OCT systems will be critical for future emerging clinical applications. We present a silicon photonic integrated circuit swept-source OCT (SS-OCT) coherent receiver with dual polarization, dual balanced, in-phase and quadrature (IQ) detection. We demonstrate multiple functional capabilities of IQ polarization resolved detection including: complex-conjugate suppressed full-range OCT, polarization diversity detection, and polarization-sensitive OCT. To our knowledge, this is the first demonstration of a silicon photonic integrated receiver for OCT. The integrated coherent receiver provides a miniaturized, low-cost solution for SS-OCT, and is also a key step towards a fully integrated high speed SS-OCT system with good performance and multi-functional capabilities. With further performance improvement and cost reduction, photonic integrated technology promises to greatly increase penetration of OCT systems in existing applications and enable new applications.

  11. Using Dual Isotopes and a Bayesian Isotope Mixing Model to Evaluate Nitrate Sources of Surface Water in a Drinking Water Source Watershed, East China

    Directory of Open Access Journals (Sweden)

    Meng Wang

    2016-08-01

    Full Text Available A high concentration of nitrate (NO3− in surface water threatens aquatic systems and human health. Revealing nitrate characteristics and identifying its sources are fundamental to making effective water management strategies. However, nitrate sources in multi-tributaries and mix land use watersheds remain unclear. In this study, based on 20 surface water sampling sites for more than two years’ monitoring from April 2012 to December 2014, water chemical and dual isotopic approaches (δ15N-NO3− and δ18O-NO3− were integrated for the first time to evaluate nitrate characteristics and sources in the Huashan watershed, Jianghuai hilly region, China. Nitrate-nitrogen concentrations (ranging from 0.02 to 8.57 mg/L were spatially heterogeneous that were influenced by hydrogeological and land use conditions. Proportional contributions of five potential nitrate sources (i.e., precipitation; manure and sewage, M & S; soil nitrogen, NS; nitrate fertilizer; nitrate derived from ammonia fertilizer and rainfall were estimated by using a Bayesian isotope mixing model. The results showed that nitrate sources contributions varied significantly among different rainfall conditions and land use types. As for the whole watershed, M & S (manure and sewage and NS (soil nitrogen were major nitrate sources in both wet and dry seasons (from 28% to 36% for manure and sewage and from 24% to 27% for soil nitrogen, respectively. Overall, combining a dual isotopes method with a Bayesian isotope mixing model offered a useful and practical way to qualitatively analyze nitrate sources and transformations as well as quantitatively estimate the contributions of potential nitrate sources in drinking water source watersheds, Jianghuai hilly region, eastern China.

  12. Adenosine improves cardiomyocyte respiratory efficiency.

    Science.gov (United States)

    Babsky, A M; Doliba, M M; Doliba, N M; Osbakken, M D

    1998-01-01

    The role of adenosine on the regulation of mitochondrial function has been studied. In order to evaluate this the following experiments were done in isolated rat cardiomyocites and mitochondria using polarographic techniques. Cardiomyocyte oxygen consumption (MVO2) and mitochondrial respiratory function (State 3 and State 4, respiratory control index, and ADP/O ratio) were evaluated after exposure to adenosine. Cardiomyocyte MVO2 was significantly lower in cells previously exposed to adenosine (10 microM, 15 min or 30 min cell incubation) than in cells not exposed to adenosine (control). Addition of dipyridamole (10 microM) or 8-(p-Sulfophenyl) theophylline (50 microM) to cardiomyocytes before adenosine incubation prevented the adenosine-induced changes in MVO2. Mitochondria obtained from isolated perfused beating heart previously perfused with adenosine (10 microM, 30 min heart perfusion) also resulted in significant increases in ADP/O and respiratory control index compared to matching control. Mitochondria isolated from cardiomyocytes previously exposed to adenosine (10 microM, 15 min or 30 min cell incubation) resulted in a significant increase in mitochondrial ADP/O ratio compared to control. Adenosine-induced decrease in cardiomyocyte MVO2 may be related to an increase in efficiency of mitochondrial oxidative phosphorylation, and more economical use of oxygen, which is necessary for survival under ischemic stress.

  13. Assessment of left ventricular function and mass in dual-source computed tomography coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Christoph J., E-mail: c.jensen@contilia.d [Department of Cardiology and Angiology, Elisabeth Hospital, Essen (Germany); Jochims, Markus [Department of Cardiology and Angiology, Elisabeth Hospital, Essen (Germany); Hunold, Peter; Forsting, Michael; Barkhausen, Joerg [Department of Diagnostic and Interventional Radiology and Neuroradiology, University of Essen (Germany); Sabin, Georg V.; Bruder, Oliver [Department of Cardiology and Angiology, Elisabeth Hospital, Essen (Germany); Schlosser, Thomas [Department of Diagnostic and Interventional Radiology and Neuroradiology, University of Essen (Germany)

    2010-06-15

    Purpose: To quantify left ventricular (LV) function and mass (LVM) derived from dual-source computed tomography (DSCT) and the influence of beta-blocker administration compared to cardiac magnetic resonance imaging (CMR). Methods: Thirty-two patients undergoing cardiac DSCT and CMR were included, where of fifteen received metoprolol intravenously before DSCT. LV parameters were calculated by the disc-summation method (DSM) and by a segmented region-growing algorithm (RGA). All data sets were analyzed by two blinded observers. Interobserver agreement was tested by the intraclass correlation coefficient. Results.: 1. Using DSM LV parameters were not statistically different between DSCT and CMR in all patients (DSCT vs. CMR: EF 63 {+-} 8% vs. 64 {+-} 8%, p = 0.47; EDV 136 {+-} 36 ml vs. 138 {+-} 35 ml, p = 0.66; ESV 52 {+-} 21 ml vs. 52 {+-} 22 ml, p = 0.61; SV 83 {+-} 22 ml vs. 87 {+-} 19 ml, p = 0.22; CO 5.4 {+-} 0.9 l/min vs. 5.7 {+-} 1.2 l/min, p = 0.09, LVM 132 {+-} 33 g vs. 132 {+-} 33 g, p = 0.99). 2. In a subgroup of 15 patients beta-blockade prior to DSCT resulted in a lower ejection fraction (EF), stroke volume (SV), cardiac output (CO) and increase in end systolic volume (ESV) in DSCT (EF 59 {+-} 8% vs. 62 {+-} 9%; SV 73 {+-} 17 ml vs. 81 {+-} 15 ml; CO 5.7 {+-} 1.2 l/min vs. 5.0 {+-} 0.8 l/min; ESV 52 {+-} 27 ml vs. 57 {+-} 24 ml, all p < 0.05). 3. Analyzing the RGA parameters LV volumes were not significantly different compared to DSM, whereas LVM was higher using RGA (177 {+-} 31 g vs. 132 {+-} 33 g, p < 0.05). Interobserver agreement was excellent comparing DSM values with best agreement between RGA calculations. Conclusion: Left ventricular volumes and mass can reliably be assessed by DSCT compared to CMR. However, beta-blocker administration leads to statistically significant reduced EF, SV and CO, whereas ESV significantly increases. DSCT RGA reliably analyzes LV function, whereas LVM is overestimated compared to DSM.

  14. Comparison of Aortic Valve Area Measured by Magnetic Resonance Imaging and Dual-Source Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bruder, O.; Jochims, M.; Jensen, C.; Sabin, G.V. (Dept. of Cardiology and Angiology, Elisabeth Hospital Essen (Germany)); Hunold, P.; Forsting, M.; Barkhausen, J.; Schlosser, T. (Dept. of Diagnostic and Interventional Radiology and Neuroradiology, Univ. Hospital Essen, Univ. of Duisburg-Essen (Germany))

    2009-07-15

    Background: Aortic valve stenosis is the most common type of valve lesion in Europe and North America. Patient treatment is based on disease severity, which is classified by determining the aortic valve area (AVA). Purpose: To compare dual-source computed tomography (DSCT) with magnetic resonance (MR) imaging for quantifying AVA. Material and Methods: Thirty-two patients, 28 with normal aortic valve function and four with aortic valve stenosis, who underwent DSCT coronary angiography (Somatom Definition; Siemens, Erlangen, Germany), were included in this study. Retrospective ECG-gated contrast-enhanced DSCT scans with dose-reducing tube current modulation were performed, and data sets were reconstructed in 3% steps of the R-R interval (slice thickness 0.75 mm, increment 0.6 mm). Planimetry of the AVA in systole was assessed on cross-sectional images by multiplanar reformations. Within 48 hours, MR was performed with a 1.5T scanner (Magnetom Sonata; Siemens, Erlangen, Germany) using a balanced steady-state free-precession cine sequence (repetition/echo time 3/1.5 ms, flip angle 60 deg, spatial resolution 1.4x1.4 mm2). Cine sequences of the left ventricular outflow tract (LVOT) were obtained in two orthogonal planes, and MR planimetry was performed on cross-sectional images of the aortic valve perpendicular to the LVOT images. Results: AVA assessment by DSCT and MR was feasible in all 32 patients. Mean AVA values determined by DSCT and MR were 4.73+-1.5 cm2 and 4.69+-1.4 cm2, respectively. A strong positive correlation was found between both imaging modalities (R=0.98, P<0.001). Bland-Altman analysis demonstrated an excellent intermodality agreement, with a slight underestimation of AVA by DSCT. The mean difference was -0.04 cm2, with a standard deviation of 0.32 cm2. Conclusion: Retrospective ECG-gated contrast-enhanced DSCT with tube current modulation provides an accurate imaging technique for the assessment of the AVA. Further studies are required to determine

  15. Dual-Source Computed Tomography Evaluation of Children with Congenital Pulmonary Valve Stenosis

    Directory of Open Access Journals (Sweden)

    Sun

    2016-03-01

    Full Text Available Background Despite dual-source computed tomography (DSCT technology has been performed well on adults or infants with heart disease, specific knowledge about children with congenital pulmonary valve stenosis (PS remained to be established. Objectives This original research aimed to establish a professional approach of DSCT performing technology on children and to assess the image quality performed by DSCT to establish a diagnostic evaluation for children with PS. Patients and Methods Ninety-eight children with congenital PS referred to affiliated hospital of Jining medical college were recruited from October 2013 to March 2015. Participants were divided into four groups according to different ages (0 - 1, 1 - 3, 3 - 7, 7 - 14, or three groups according to different heart rates ( 110. Image quality of pulmonary valves was assessed based on a four-point grading scale (1 - 4 points. Those cases achieving a score of ≥ 3 points were selected for further investigation, which played a critical role in our analysis. Correlation analysis was used to identify the effects of age and heart rate on image quality. Additionally, the results evaluated by DSCT were compared with those evaluated from the operation, further confirming the accuracy of DSCT. Results Seventy-two cases (73.4% achieved a score of ≥ 3 points based on pulmonary valve imaging, which were available for further diagnosis. There was a statistically significant difference (P < 0.05 between the four groups except 0 - 1 group and 1 - 3 group, 3 - 7 group and 7 - 14 group, and the image quality of elder group was higher than younger group. Image score was gradually decreased with increased heart rate (F = 19.05, P < 0.01. Heart rate was negatively correlated with pulmonary valve scores (r = -0.391, P < 0.001, while there was no correlation between age and scores (r = 0.185, P = 0.070. The number, shape, commissure, and opening status of pulmonary valves evaluated by DSCT were the same as the

  16. WORK-FAMILY CONFLICT AND SOURCES OF SUPPORT AMONGST MALAYSIAN DUAL-CAREER EMPLOYEES

    Directory of Open Access Journals (Sweden)

    Meera Komarraju

    2006-01-01

    Full Text Available As the number of dual-career employees entering the workplace increases, it is important to understand how the integration of work and family responsibilities influences work outcomes. The current study examined occupational role salience, work-family conflict, basic understandings, spousal support, and organizational support as predictors of work satisfaction. One hundred and sixteen dual-career faculty and staff from three Malaysian universities completed a survey questionnaire. Results from stepwise regression analyses showed that across all employees, work-family conflict was the most significant predictor of work satisfaction. More specifically, for male employees, spousal support was the most important predictor of work satisfaction followed by work-family conflict. Interestingly, for female employees, work-family conflict was the most significant predictor followed by organizational support. These results suggest that dual-career employees who find family responsibilities intruding into their work activities are likely to experience lesser work satisfaction. Dual-career employees receiving support and encouragement from a spouse or from the employing organization are more likely to experience increased work satisfaction.

  17. Impact of an advanced image-based monoenergetic reconstruction algorithm on coronary stent visualization using third generation dual-source dual-energy CT: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Stefanie [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Cannao, Paola M. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Milan, Scuola di Specializzazione in Radiodiagnostica, Milan (Italy); Schoepf, U.J. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Wichmann, Julian L. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Canstein, Christian [Siemens Medical Solutions, Malvern, PA (United States); Fuller, Stephen R.; Varga-Szemes, Akos [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Muscogiuri, Giuseppe; De Cecco, Carlo N. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2016-06-15

    To evaluate the impact of an advanced monoenergetic (ME) reconstruction algorithm on CT coronary stent imaging in a phantom model. Three stents with lumen diameters of 2.25, 3.0 and 3.5 mm were examined with a third-generation dual-source dual-energy CT (DECT). Tube potential was set at 90/Sn150 kV for DE and 70, 90 or 120 kV for single-energy (SE) acquisitions and advanced modelled iterative reconstruction was used. Overall, 23 reconstructions were evaluated for each stent including three SE acquisitions and ten advanced and standard ME images with virtual photon energies from 40 to 130 keV, respectively. In-stent luminal diameter was measured and compared to nominal lumen diameter to determine stent lumen visibility. Contrast-to-noise ratio was calculated. Advanced ME reconstructions substantially increased lumen visibility in comparison to SE for stents ≤3 mm. 130 keV images produced the best mean lumen visibility: 86 % for the 2.25 mm stent (82 % for standard ME and 64 % for SE) and 82 % for the 3.0 mm stent (77 % for standard ME and 69 % for SE). Mean DLP for SE 120 kV and DE acquisitions were 114.4 ± 9.8 and 58.9 ± 2.2 mGy x cm, respectively. DECT with advanced ME reconstructions improves the in-lumen visibility of small stents in comparison with standard ME and SE imaging. (orig.)

  18. Plug-and-play Integration of dual-model based Knowledge Artefacts into an Open Source Ehr System.

    Science.gov (United States)

    Krexner, Rabea; Duftschmid, Georg

    2014-01-01

    In this paper we present our experiences with extending an existing approach for an archetype-compliant collection and export of data according to the openEHR specifications within the open source EHR system OpenMRS. It allows an automatic generation of forms from templates, which were introduced by openEHR as an extension of the dual-model approach. Data entered in these forms can be exported in form of standardized EHR extracts. The use of templates allowed us to solve problems reported for the original archetype-based version of the approach, which were caused by the high optionality within archetypes.

  19. Heat Source/Sink in a Magneto-Hydrodynamic Non-Newtonian Fluid Flow in a Porous Medium: Dual Solutions.

    Science.gov (United States)

    Hayat, Tasawar; Awais, Muhammad; Imtiaz, Amna

    2016-01-01

    This communication deals with the properties of heat source/sink in a magneto-hydrodynamic flow of a non-Newtonian fluid immersed in a porous medium. Shrinking phenomenon along with the permeability of the wall is considered. Mathematical modelling is performed to convert the considered physical process into set of coupled nonlinear mathematical equations. Suitable transformations are invoked to convert the set of partial differential equations into nonlinear ordinary differential equations which are tackled numerically for the solution computations. It is noted that dual solutions for various physical parameters exist which are analyzed in detail.

  20. Imaging Adenosine Triphosphate (ATP).

    Science.gov (United States)

    Rajendran, Megha; Dane, Eric; Conley, Jason; Tantama, Mathew

    2016-08-01

    Adenosine triphosphate (ATP) is a universal mediator of metabolism and signaling across unicellular and multicellular species. There is a fundamental interdependence between the dynamics of ATP and the physiology that occurs inside and outside the cell. Characterizing and understanding ATP dynamics provide valuable mechanistic insight into processes that range from neurotransmission to the chemotaxis of immune cells. Therefore, we require the methodology to interrogate both temporal and spatial components of ATP dynamics from the subcellular to the organismal levels in live specimens. Over the last several decades, a number of molecular probes that are specific to ATP have been developed. These probes have been combined with imaging approaches, particularly optical microscopy, to enable qualitative and quantitative detection of this critical molecule. In this review, we survey current examples of technologies available for visualizing ATP in living cells, and identify areas where new tools and approaches are needed to expand our capabilities.

  1. Dual-modal photoacoustic and optical coherence tomography using a single near-infrared supercontinuum laser source

    Science.gov (United States)

    Lee, Changho; Han, Seunghoon; Kim, Sehui; Jeon, Minyoung; Jeon, Mansik; Kim, Chulhong; Kim, Jeehyun

    2013-03-01

    We report the development of a combined dual-modal photoacoustic and optical coherence tomography (PA-OCT) system using a single near-infrared (NIR) supercontinuum laser source which can provide both optical absorption and scattering contrasts simultaneously. By using a small sized pulsed Nd:YAG microchip laser and a photonic crystal fiber, we fabricated a pulsed broadband supercontinuum source from 600 to 1700 nm. Under the same optical hardware system, intrinsically registered PA and OCT images are acquired in a single scanning. In order to demonstrate feasibility of our system, we successfully acquired the PA and OCT images of black and white hairs images at the same time. The black hair was detected in both PA and OCT images, while the white hair appeared only in the OCT image. This result suggests the potential of compact, cost-effective, and simple dual-modal PA-OCT system. Moreover, we believe that this approach will be a key point for commercialization and clinical translation.

  2. Dual source multidetector CT-angiography before transcatheter aortic valve implantation (TAVI) using a high-pitch spiral acquisition mode

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, W.; Anders, K.; May, M.S.; Uder, M. [University of Erlangen, Department of Radiology, Erlangen (Germany); Schuhbaeck, A.; Gauss, S.; Marwan, M.; Arnold, M.; Muschiol, G.; Daniel, W.G.; Achenbach, S. [University of Erlangen, Department of Cardiology, Erlangen (Germany); Ensminger, S. [University of Erlangen, Department of Cardiac Surgery, Erlangen (Germany)

    2012-01-15

    Transcatheter Aortic Valve Implantation (TAVI) is an alternative to surgical valve replacement in high risk patients. Angiography of the aortic root, aorta and iliac arteries is required to select suitable candidates, but contrast agents can be harmful due to impaired renal function. We evaluated ECG-triggered high-pitch spiral dual source Computed Tomography (CT) with minimized volume of contrast agent to assess aortic root anatomy and vascular access. 42 patients (82 {+-} 6 years) scheduled for TAVI underwent dual source (DS) CT angiography (CTA) of the aorta using a prospectively ECG-triggered high-pitch spiral mode (pitch = 3.4) with 40 mL iodinated contrast agent. We analyzed aortic root/iliac dimensions, attenuation, contrast to noise ratio (CNR), image noise and radiation exposure. Aortic root/iliac dimensions and distance of coronary ostia from the annulus could be determined in all cases. Mean aortic and iliac artery attenuation was 320 {+-} 70 HU and 340 {+-} 77 HU. Aortic/iliac CNR was 21.7 {+-} 6.8 HU and 14.5 {+-} 5.4 HU using 100 kV (18.8 {+-} 4.1 HU and 8.7 {+-} 2.6 HU using 120 kV). Mean effective dose was 4.5 {+-} 1.2 mSv. High-pitch spiral DSCTA can be used to assess the entire aorta and iliac arteries in TAVI candidates with a low volume of contrast agent while preserving diagnostic image quality. (orig.)

  3. Scheduling for dual-hop block-fading channels with two source-user pairs sharing one relay

    KAUST Repository

    Zafar, Ammar

    2013-09-01

    In this paper, we maximize the achievable rate region of a dual-hop network with two sources serving two users independently through a single shared relay. We formulate the problem as maximizing the sum of the weighted long term average throughputs of the two users under stability constraints on the long term throughputs of the source-user pairs. In order to solve the problem, we propose a joint user-and-hop scheduling scheme, which schedules the first or second hop opportunistically based on instantaneous channel state information, in order to exploit multiuser diversity and multihop diversity gains. Numerical results show that the proposed joint scheduling scheme enhances the achievable rate region as compared to a scheme that employs multi-user scheduling on the second-hop alone. Copyright © 2013 by the Institute of Electrical and Electronic Engineers, Inc.

  4. Confirmation of a conspiracy - Dual-band VLBI maps of the flat-spectrum radio source 2021 + 614

    Science.gov (United States)

    Wittels, J. J.; Shapiro, I. I.; Cotton, W. D.

    1982-01-01

    VLBI observations at 3.6 and 13 cm wavelengths of the flat-spectrum radio source 2021 + 614 reveal two components, separated by about 6.5 + or - 0.6 milli-arcseconds along a position angle of 36 deg + or - 6 deg. The dual-band observations show that the two components have spectral indices of opposite signs, indicating that, as for 0735 + 178 (Cotton et al. 1980), the flat spectrum of 2021 + 614 is a result of the superposition of spectra from individual components, each having a peaked spectrum, presumably due to incoherent electron synchrotron radiation. If this situation is typical, then there is too large a percentage of flat-spectrum sources for the individual components in each to have independent characteristics.

  5. Fire Source Localization Based on Distributed Temperature Sensing by a Dual-Line Optical Fiber System.

    Science.gov (United States)

    Sun, Miao; Tang, Yuquan; Yang, Shuang; Li, Jun; Sigrist, Markus W; Dong, Fengzhong

    2016-06-06

    We propose a method for localizing a fire source using an optical fiber distributed temperature sensor system. A section of two parallel optical fibers employed as the sensing element is installed near the ceiling of a closed room in which the fire source is located. By measuring the temperature of hot air flows, the problem of three-dimensional fire source localization is transformed to two dimensions. The method of the source location is verified with experiments using burning alcohol as fire source, and it is demonstrated that the method represents a robust and reliable technique for localizing a fire source also for long sensing ranges.

  6. Nitrate source apportionment using a combined dual isotope, chemical and bacterial property, and Bayesian model approach in river systems

    Science.gov (United States)

    Xia, Yongqiu; Li, Yuefei; Zhang, Xinyu; Yan, Xiaoyuan

    2017-01-01

    Nitrate (NO3-) pollution is a serious problem worldwide, particularly in countries with intensive agricultural and population activities. Previous studies have used δ15N-NO3- and δ18O-NO3- to determine the NO3- sources in rivers. However, this approach is subject to substantial uncertainties and limitations because of the numerous NO3- sources, the wide isotopic ranges, and the existing isotopic fractionations. In this study, we outline a combined procedure for improving the determination of NO3- sources in a paddy agriculture-urban gradient watershed in eastern China. First, the main sources of NO3- in the Qinhuai River were examined by the dual-isotope biplot approach, in which we narrowed the isotope ranges using site-specific isotopic results. Next, the bacterial groups and chemical properties of the river water were analyzed to verify these sources. Finally, we introduced a Bayesian model to apportion the spatiotemporal variations of the NO3- sources. Denitrification was first incorporated into the Bayesian model because denitrification plays an important role in the nitrogen pathway. The results showed that fertilizer contributed large amounts of NO3- to the surface water in traditional agricultural regions, whereas manure effluents were the dominant NO3- source in intensified agricultural regions, especially during the wet seasons. Sewage effluents were important in all three land uses and exhibited great differences between the dry season and the wet season. This combined analysis quantitatively delineates the proportion of NO3- sources from paddy agriculture to urban river water for both dry and wet seasons and incorporates isotopic fractionation and uncertainties in the source compositions.

  7. Volumetric evaluation of dual-energy perfusion CT by the presence of intrapulmonary clots using a 64-slice dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Munemasa; Nakashima, Yoshiteru; Kunihiro, Yoshie; Nakao, Sei; Matsunaga, Naofumi [Dept. of Radiology, Yamaguchi Univ. Graduate School of Medicine, Yamaguchi (Japan)], e-mail: radokada@yamaguchi-u.ac.jp; Morikage, Noriyasu [Medical Bioregulation Dept. of Organ Regulatory Surgery, Yamaguchi Univ. Graduate School of Medicine, Yamaguchi (Japan); Sano, Yuichi [Dept. of Radiology, Yamaguchi Univ. Hospital, Yamaguchi (Japan); Suga, Kazuyoshi [Dept. of Radiology, St Hills Hospital, Yamaguchi (Japan)

    2013-07-15

    Background: Dual-energy perfusion CT (DE{sub p}CT) directly represents the iodine distribution in lung parenchyma and low perfusion areas caused by intrapulmonary clots (IPCs) are visualized as low attenuation areas. Purpose: To evaluate if volumetric evaluation of DE{sub p}CT can be used as a predictor of right heart strain by the presence of IPCs. Material and Methods: One hundred and ninety-six patients suspected of having acute pulmonary embolism (PE) underwent DE{sub p}CT using a 64-slice dual-source CT. DE{sub p}CT images were three-dimensionally reconstructed with four threshold ranges: 1-120 HU (V{sub 120}), 1-15 HU (V{sub 15}), 1-10 HU (V{sub 10}), and 1-5 HU (V{sub 5}). Each relative ratio per V{sub 120} was expressed as the %V{sub 15}, %V{sub 10}, and %V{sub 5}. Volumetric data-sets were compared with D-dimer, pulmonary arterial (PA) pressure, right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio, PA diameter, and PA/aorta (PA/Ao) diameter ratio. The areas under the ROC curves (AUCs) were examined for their relationship to the presence of IPCs. This study was approved by the local ethics committee. Results: PA pressure and D-dimer were significantly higher in the patients who had IPCs. In the patients with IPCs, V{sub 15}, V{sub 10}, V{sub 5}, %V{sub 15}, %V{sub 10}, and %V{sub 5} were also significantly higher than those without IPC (P = 0.001). %V{sub 5} had a better correlation with D-dimer (r = 0.30, P < 0.001) and RV/LV diameter ratio (r = 0.27, P < 0.001), and showed a higher AUC (0.73) than the other CT measurements. Conclusion: The volumetric evaluation by DE{sub p}CT had a correlation with D-dimer and RV/LV diameter ratio, and the relative ratio of volumetric CT measurements with a lower attenuation threshold might be recommended for the analysis of acute PE.

  8. Some neural effects of adenosin.

    Science.gov (United States)

    Haulică, I; Brănişteanu, D D; Petrescu, G H

    1978-01-01

    The possible neural effects of adenosine were investigated by using electrophysiological techniques at the level of some central and peripheral synapses. The evoked potentials in the somatosensorial cerebral cortex are influenced according to both the type of administration and the level of the electrical stimulation. While the local application does not induce significant alterations, the intrathalamic injections and the perfusion of the IIIrd cerebral ventricle do change the distribution of activated units at the level of different cortical layers especially during the peripheral stimulation. The frequency of spontaneous miniature discharges intracellularly recorded in the neuromuscular junction (mepp) is significantly depressed by adenosine. This effect is calcium- and dose-dependent. The end plate potentials (EPP) were also depressed. The statistical binomial analysis of the phenomenon indicated that adenosine induces a decrease if the presynaptic pool of the available transmitter. The data obtained demonstrate a presynaptic inhibitory action of adenosine beside its known vascular and metaholic effects.

  9. Dual Solutions of MHD Boundary Layer Flow past an Exponentially Stretching Sheet with Non-Uniform Heat Source/Sink

    Directory of Open Access Journals (Sweden)

    Raju CSK

    2016-01-01

    Full Text Available In this study we analyzed the momentum and heat transfer characteristics of MHD boundary layer flow over an exponentially stretching surface in porous medium in the presence of radiation, non-uniform heat source/sink, external pressure and suction/injection. Dual solutions are presented for both suction and injection cases. The heat transfer analysis is carried out for both prescribed surface temperature (PST and prescribed heat flux (PHF cases. The governing equations of the flow are transformed into system of nonlinear ordinary differential equations by using similarity transformation and solved numerically using bvp4c Matlab package. The impact of various non-dimensional governing parameters on velocity, temperature profiles for both PST and PHF cases, friction factor and rate of heat transfer is discussed and presented with the help of graphs and tables. Results indicate that dual solutions exist only for certain range of suction or injection parameters. It is also observed that the exponential parameter have tendency to increase the heat transfer rate for both PST and PHF cases.

  10. Xenon ventilation CT using dual-source and dual-energy technique in children with bronchiolitis obliterans: correlation of xenon and CT density values with pulmonary function test results

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo; Yang, Dong Hyun; Seo, Joon Beom; Chae, Eun Jin; Lee, Jeongjin [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Songpa-gu, Seoul (Korea); Hong, Soo-Jong; Yu, Jinho; Kim, Byoung-Ju [University of Ulsan College of Medicine, Department of Pediatrics, Asan Medical Center, Seoul (Korea); Krauss, Bernhard [Siemens Medical Solutions AG-Computed Tomography, Forchheim (Germany)

    2010-09-15

    Xenon ventilation CT using dual-source and dual-energy technique is a recently introduced, promising functional lung imaging method. To expand its clinical applications evidence of additional diagnostic value of xenon ventilation CT over conventional chest CT is required. To evaluate the usefulness of xenon ventilation CT using dual-source and dual-energy technique in children with bronchiolitis obliterans (BO). Seventeen children (age 7-18 years; 11 boys) with BO underwent xenon ventilation CT using dual-source and dual-energy technique. Xenon and CT density values were measured in normal and hyperlucent lung regions on CT and were compared between the two regions. Volumes of hyperlucent regions and ventilation defects were calculated with thresholds determined by visual and histogram-based analysis. Indexed volumes of hyperlucent lung regions and ventilation defects were correlated with pulmonary function test results. Effective doses of xenon CT were calculated. Xenon (14.6 {+-} 6.4 HU vs 26.1 {+-} 6.5 HU; P < 0.001) and CT density (-892.8 {+-} 25.4 HU vs -812.3 {+-} 38.7 HU; P < 0.001) values were significantly lower in hyperlucent regions than in normal lung regions. Xenon and CT density values showed significant positive correlation for the entire lung in 16 children ({gamma} = 0.55 {+-} 0.17, P < 0.001 or =0.017) and for hyperlucent regions in 13 children ({gamma} = 0.44 {+-} 0.16, P < 0.001 or =0.001-0.019). Indexed volumes and volume percentages of hyperlucent lung regions and ventilation defects showed strong negative correlations with forced expiratory volume [FEV1, ({gamma} = -0.64-0.85, P {<=} 0.006)], FEV1/forced vital capacity [FVC, ({gamma} = -0.63-0.84, P {<=} 0.008)], and forced midexpiratory flow rate [FEF{sub 25-75}, ({gamma} = -0.68-0.88, P {<=} 0.002). Volume percentages of xenon ventilation defects (35.0 {+-} 16.4%)] were not significantly different from those of hyperlucent lung regions (38.2 {+-} 18.6%). However, mismatches between the

  11. Dual isotope notch observer for isotope identification, assay and imaging with mono-energetic gamma-ray sources

    Science.gov (United States)

    Barty, Christopher P.J.

    2013-02-05

    A dual isotope notch observer for isotope identification, assay and imaging with mono-energetic gamma-ray sources includes a detector arrangement consists of three detectors downstream from the object under observation. The latter detector, which operates as a beam monitor, is an integrating detector that monitors the total beam power arriving at its surface. The first detector and the middle detector each include an integrating detector surrounding a foil. The foils of these two detectors are made of the same atomic material, but each foil is a different isotope, e.g., the first foil may comprise U235 and second foil may comprise U238. The integrating detectors surrounding these pieces of foil measure the total power scattered from the foil and can be similar in composition to the final beam monitor. Non-resonant photons will, after calibration, scatter equally from both foils.

  12. Automatic selection of an optimal systolic and diastolic reconstruction windows for dual-source CT coronary angiography

    Science.gov (United States)

    Seifarth, H.; Puesken, M.; Wienbeck, S.; Maintz, D.; Heindel, W.; Juergens, K.-U.

    2008-03-01

    Purpose: To assess the performance of a motion map algorithm to automatically determine the optimal systolic and diastolic reconstruction window for coronary CT Angiography using Dual Source CT. Materials and Methods: Dual Source coronary CT angiography data sets (Somatom Definition, Siemens Medical Solutions) from 50 consecutive patients were included in the analysis. Optimal systolic and diastolic reconstruction windows were determined using a motion map algorithm (BestPhase, Siemens Medical Solutions). Additionally data sets were reconstructed in 5% steps throughout the RR-interval. For each major vessel (RCA, LAD and LCX) an optimal systolic and diastolic reconstruction window was manually determined by two independent readers using volume rendering displays. Image quality was rated using a five-point scale (1 = no motion artifacts, 5 = severe motion artifacts over entire length of the vessel). Results: The mean heart rate during the scan was 72.4bpm (+/-15.8bpm). Median systolic and diastolic reconstruction windows using the BestPhase algorithm were at 37% and 73% RR. The median manually selected systolic reconstruction window was 35 %, 30% and 35% for RCA, LAD, and LCX. For all vessels the median observer selected diastolic reconstruction window was 75%. Mean image quality using the BestPhase algorithm was 2.4 +/-0.9 for systolic reconstructions and 1.9 +/-1.1 for diastolic reconstructions. Using the manual approach, the mean image quality was 1.9 +/-0.5 and 1.7 +/-0.8 respectively. There was a significant difference in image quality between automatically and manually determined systolic reconstructions (p<0.01) but there was no significant difference in image quality in diastolic reconstructions. Conclusion: Automatic determination of the optimal reconstruction interval using the BestPhase algorithm is feasible and yields reconstruction windows similar to observer selected reconstruction windows. In diastolic reconstructions overall image quality is similar

  13. Energy Limits in Second Generation High-pitch Dual Source CT - Comparison in an Upper Abdominal Phantom

    Directory of Open Access Journals (Sweden)

    Martin Beeres

    2015-01-01

    Full Text Available Objectives: The aim of our study was to find out how much energy is applicable in second-generation dual source high-pitch computed tomography (CT in imaging of the abdomen. Materials and Methods: We examined an upper abdominal phantom using a Somatom Definition Flash CT-Scanner (Siemens, Forchheim, Germany. The study protocol consisted of a scan-series at 100 kV and 120 kV. In each scan series we started with a pitch of 3.2 and reduced it in steps of 0.2, until a pitch of 1.6 was reached. The current was adjusted to the maximum the scanner could achieve. Energy values, image noise, image quality, and radiation exposure were evaluated. Results: For a pitch of 3.2 the maximum applicable current was 142 mAs at 120 kV and in 100 kV the maximum applicable current was 114 mAs. For conventional abdominal imaging, current levels of 200 to 260 mAs are generally used. To achieve similar current levels, we had to decrease the pitch to 1.8 at 100 kV - at this pitch we could perform our imaging at 204 mAs. At a pitch of 2.2 in 120 kV we could apply a current of 206 mAs. Conclusion: We conclude our study by stating that if there is a need for a higher current, we have to reduce the pitch. In a high-pitch dual source CT, we always have to remember where our main focus is, so we can adjust the pitch to the energy we need in the area of the body that has to be imaged, to find answers to the clinical question being raised.

  14. High-pitch coronary CT angiography with third generation dual-source CT: limits of heart rate.

    Science.gov (United States)

    Gordic, Sonja; Husarik, Daniela B; Desbiolles, Lotus; Leschka, Sebastian; Frauenfelder, Thomas; Alkadhi, Hatem

    2014-08-01

    To determine the average heart rate (HR) and heart rate variability (HRV) required for diagnostic imaging of the coronary arteries in patients undergoing high-pitch CT-angiography (CTA) with third-generation dual-source CT. Fifty consecutive patients underwent CTA of the thoracic (n = 8) and thoracoabdominal (n = 42) aorta with third-generation dual-source 192-slice CT with prospective electrocardiography (ECG)-gating at a pitch of 3.2. No β-blockers were administered. Motion artifacts of coronary arteries were graded on a 4-point scale. Average HR and HRV were noted. The average HR was 66 ± 11 beats per minute (bpm) (range 45-96 bpm); the HRV was 7.3 ± 4.4 bpm (range 3-20 bpm). Interobserver agreement on grade of image quality for the 642 coronary segments evaluated by both observers was good (κ = 0.71). Diagnostic image quality was found for 608 of the 642 segments (95%) in 43 of 50 patients (86%). In 14% of the patients, image quality was nondiagnostic for at least one segment. HR (p = 0.001) was significantly higher in patients with at least one non-diagnostic segment compared to those without. There was no significant difference (p > 0.05) in HRV between patients with nondiagnostic segments and those with diagnostic images of all segments. All patients with a HR CT allows for coronary angiography in the prospectively ECG-gated high-pitch mode with diagnostic image quality at HR up to 70 bpm. HRV is not significantly related to image quality of coronary CTA.

  15. High-pitch dual-source CT angiography of the aortic valve-aortic root complex without ECG-synchronization

    Energy Technology Data Exchange (ETDEWEB)

    Karlo, Christoph; Leschka, Sebastian; Goetti, Robert Paul; Feuchtner, Gudrun; Desbiolles, Lotus; Stolzmann, Paul; Marincek, Borut; Baumueller, Stephan [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Plass, Andre; Falk, Volkmar [University Hospital Zurich, Clinic for Cardiovascular Surgery, Zurich (Switzerland); Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Massachusetts General Hospital, Harvard Medical School, Cardiac MR PET CT Group, Boston, MA (United States)

    2011-01-15

    To compare image quality and radiation dose of high-pitch computed tomography angiography(CTA) of the aortic valve-aortic root complex with and without prospective ECG-gating compared to a retrospectively ECG-gated standard-pitch acquisition. 120 patients(mean age 68 {+-} 13 years) were examined using a 128-slice dual-source CT system using prospectively ECG-gated high-pitch(group A; n = 40), non-ECG-gated high-pitch(group B; n = 40) or retrospectively ECG-gated standard-pitch(C; n = 40) acquisition techniques. Image quality of the aortic root, valve and ascending aorta including the coronary ostia was assessed by two independent readers. Image noise was measured, radiation dose estimates were calculated. Interobserver agreement was good({kappa} = 0.64-0.78). Image quality was diagnostic in 38/40 patients(group A), 37/40(B) and 38/40(C) with no significant difference in number of patients with diagnostic image quality among all groups (p = 0.56). Significantly more patients showed excellent image quality in group A compared to groups B and C(each, p < 0.01). Average image noise was significantly different between all groups(p < 0.05). Mean radiation dose estimates in groups A and B(each; 2.4 {+-} 0.3 mSv) were significantly lower compared to group C(17.5 {+-} 4.4 mSv; p < 0.01). High-pitch dual-source CTA provides diagnostic image quality of the aortic valve-aortic root complex even without ECG-gating at 86% less radiation dose when compared to a standard-pitch ECG-gated acquisition. (orig.)

  16. Dual-source computed tomography: Estimation of radiation exposure of ECG-gated and ECG-triggered coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Ketelsen, Dominik [Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany)], E-mail: dominik.ketelsen@med.uni-tuebingen.de; Thomas, Christoph; Werner, Matthias; Luetkhoff, Marie H. [Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Buchgeister, Markus [Departments of Radiotherapy and Radiooncology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Tsiflikas, Ilias; Reimann, Anja [Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Burgstahler, Christof [Department of Cardiology, University Hospital Tuebingen, Ottfried-Mueller-Strasse 10, 72076 Tuebingen (Germany); Brodoefel, Harald; Kopp, Andreas F.; Claussen, Claus D.; Heuschmid, Martin [Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany)

    2010-02-15

    Purpose: The aim of the study was to estimate radiation exposure of coronary calcium scoring and angiography using ECG-gated and ECG-triggered dual-source computed tomography. Materials and methods: An Alderson Rando phantom equipped with thermoluminescent dosimeters was used for all dose measurements. Effective dose was calculated according to ICRP 103. Radiation exposure was performed on a dual-source computed tomography (DSCT) scanner with standard protocols for calcium scoring (DSCT-Ca) and coronary angiography (DSCTA) at different heart rates (40-100 beats/min). Furthermore, a scanning protocol with ECG-triggering as well as a standard chest CT scan were evaluated. Results: Depending on gender, heart rate and ECG-pulsing, the effective dose of a complete cardiac DSCT (DSCT-Ca and DSCTA) scan varies from 10.2 to 32.6 mSv. The effective radiation dose increased significantly with lower heart rates (p < 0.035). ECG-pulsing reduced the radiation exposure significantly in DSCTA (p < 0.001). Due to breast tissue in the primary scan range, females' doses showed an increase up to 69.9% compared to males in scan protocols without ECG-pulsing. Prospective ECG-triggered DSCTA resulted in estimated effective doses from 2.8 mSv (males) to 4.1 mSv (females). Conclusion: The ECG-pulsing technique has proven its effectiveness to reduce effective dose in coronary CT angiography and is recommended for all patients with regular heart rates. The patient's heart rate influences the radiation exposure with a significant decrease at higher heart rates. Due to its lower dose, ECG-triggered DSCTA should be implemented for special indications, i.e. for diagnosis of pathologies of the aortic root and the ascending aorta.

  17. Research on a Household Dual Heat Source Heat Pump Water Heater with Preheater Based on ASPEN PLUS

    Directory of Open Access Journals (Sweden)

    Xiang Gou

    2016-12-01

    Full Text Available This article proposes a dual heat source heat pump bathroom unit with preheater which is feasible for a single family. The system effectively integrates the air source heat pump (ASHP and wastewater source heat pump (WSHP technologies, and incorporates a preheater to recover shower wastewater heat and thus improve the total coefficient of performance (COP of the system, and it has no electric auxiliary heating device, which is favorable to improve the security of the system operation. The process simulation software ASPEN PLUS, widely used in the design and optimization of thermodynamic systems, was used to simulate various cases of system use and to analyze the impact of the preheater on the system. The average COP value of a system with preheater is 6.588 and without preheater it is 4.677. Based on the optimization and analysis, under the standard conditions of air at 25 °C, relative humidity of 70%, wastewater at 35 °C, wastewater flow rate of 0.07 kg/s, tap water at 15 °C, and condenser outlet water temperature at 50 °C, the theoretical COP of the system can reach 9.784 at an evaporating temperature of 14.96 °C, condensing temperature of 48.74 °C, and preheated water temperature of 27.19 °C.

  18. A dual neutron/gamma source for the Fissmat Inspection for Nuclear Detection (FIND) system.

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Barney Lee (Sandia National Laboratories, Albuquerque, NM); King, Michael; Rossi, Paolo (Sandia National Laboratories, Albuquerque, NM); McDaniel, Floyd Del (Sandia National Laboratories, Albuquerque, NM); Morse, Daniel Henry; Antolak, Arlyn J.; Provencio, Paula Polyak (Sandia National Laboratories, Albuquerque, NM); Raber, Thomas N.

    2008-12-01

    Shielded special nuclear material (SNM) is very difficult to detect and new technologies are needed to clear alarms and verify the presence of SNM. High-energy photons and neutrons can be used to actively interrogate for heavily shielded SNM, such as highly enriched uranium (HEU), since neutrons can penetrate gamma-ray shielding and gamma-rays can penetrate neutron shielding. Both source particles then induce unique detectable signals from fission. In this LDRD, we explored a new type of interrogation source that uses low-energy proton- or deuteron-induced nuclear reactions to generate high fluxes of mono-energetic gammas or neutrons. Accelerator-based experiments, computational studies, and prototype source tests were performed to obtain a better understanding of (1) the flux requirements, (2) fission-induced signals, background, and interferences, and (3) operational performance of the source. The results of this research led to the development and testing of an axial-type gamma tube source and the design/construction of a high power coaxial-type gamma generator based on the {sup 11}B(p,{gamma}){sup 12}C nuclear reaction.

  19. Dual-Carbon sources fuel the OCS deep-reef Community, a stable isotope investigation

    Science.gov (United States)

    Sulak, Kenneth J.; Berg, J.; Randall, Michael; Dennis, George D.; Brooks, R.A.

    2008-01-01

    The hypothesis that phytoplankton is the sole carbon source for the OCS deep-reef community (>60 m) was tested. Trophic structure for NE Gulf of Mexico deep reefs was analyzed via carbon and nitrogen stable isotopes. Carbon signatures for 114 entities (carbon sources, sediment, fishes, and invertebrates) supported surface phytoplankton as the primary fuel for the deep reef. However, a second carbon source, the macroalga Sargassum, with its epiphytic macroalgal associate, Cladophora liniformis, was also identified. Macroalgal carbon signatures were detected among 23 consumer entities. Most notably, macroalgae contributed 45 % of total carbon to the 13C isotopic spectrum of the particulate-feeding reef-crest gorgonian Nicella. The discontinuous spatial distribution of some sessile deep-reef invertebrates utilizing pelagic macroalgal carbon may be trophically tied to the contagious distribution of Sargassum biomass along major ocean surface features.

  20. Semi-automatic measurement of left ventricular function on dual source computed tomography using five different software tools in comparison with magnetic resonance imaging

    NARCIS (Netherlands)

    de Jonge, G. J.; van der Vleuten, P. A.; Overbosch, J.; Lubbers, D. D.; Jansen-van der Weide, M. C.; Zijlstra, F.; van Ooijen, P. M. A.; Oudkerk, M.

    2011-01-01

    Purpose: To compare left ventricular (LV) function assessment using five different software tools on the same dual source computed tomography (DSCT) datasets with the results of MRI. Materials and methods: Twenty-six patients, undergoing cardiac contrast-enhanced DSCT were included (20 men, mean age

  1. Integrating cut-and-solve and semi-Lagrangean based dual ascent for the single-source capacitated facility location problem

    DEFF Research Database (Denmark)

    Gadegaard, Sune Lauth

    This paper describes how the cut-and-solve framework and semi-Lagrangean based dual ascent algorithms can be integrated in two natural ways in order to solve the single source capacitated facility location problem. The first uses the cut-and-solve framework both as a heuristic and as an exact...

  2. Systematic review of the accuracy of dual-source cardiacct for detection of arterial stenosis in difficult to image patient groups

    NARCIS (Netherlands)

    M. Westwood (Marie); H. Raatz (Heike); K. Misso (Kate); L.T. Burgers (Laura); W.K. Redekop (Ken); S.K. Lhachimi (Stefan); N. Armstrong (Nigel); J. Kleijnen (Jos)

    2013-01-01

    textabstractPurpose: To assess the diagnostic performance of dual-source cardiac (DSC) computed tomography (CT) newer-generation CT instruments for identifying anatomically significant coronary artery disease (CAD) in patients who are difficult to image by using 64-section CT. Materials and Methods:

  3. Assessment of image quality of 64-row Dual Source versus Single Source CT coronary angiography on heart rate: A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Dikkers, R. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: r.dikkers@rad.umcg.nl; Greuter, M.J.W. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: m.j.w.greuter@rad.umcg.nl; Kristanto, W. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: w.kristanto@rad.umcg.nl; Ooijen, P.M.A. van [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: p.m.a.van.ooyen@rad.umcg.nl; Sijens, P.E. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: p.e.sijens@rad.umcg.nl; Willems, T.P. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: t.p.willems@rad.umcg.nl; Oudkerk, M. [Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen (Netherlands)], E-mail: m.oudkerk@rad.umcg.nl

    2009-04-15

    Purpose: To assess the influence of temporal resolution on image quality of computed tomographic (CT) coronary angiography by comparing 64-row Dual Source CT (DSCT) and Single Source CT (SSCT) at different heart rates. Methods: An anthropomorphic moving heart phantom was scanned at rest, and at 50 beats per minute (bpm) up to 110 bpm, with intervals of 10 bpm. 3D volume rendered images and curved multi-planar reconstructions (MPRs) were acquired and image quality of the coronary arteries was rated on a 5-points scale (1 = poor image quality with many artefacts, 5 = excellent image quality) for each heart rate and each scanner by 3 observers. Paired sample t-test and Wilcoxon Signed Ranks test were used to assess clinically relevant differences between both modalities. Results: The mean image quality scores at 70, 100 and 110 bpm were significantly higher for DSCT compared to SSCT. The overall mean image quality scores for DSCT (4.2 {+-} 0.6) and SSCT (3.0 {+-} 1.1) also differed significantly (p < 0.001). Conclusion: These initial results show a clinically relevant overall higher image quality for DSCT compared to SSCT, especially at heart rates of 70, 100 and 110 bpm. With its comparatively high image quality and low radiation dose, DSCT appears to be the method of choice in CT coronary angiography at heart rates above 70 bpm.

  4. A Dirichlet-integral based dual-access collocation-kernel approach to point-source gravity-field modleing

    CERN Document Server

    Rufty, A

    2006-01-01

    Problems in $\\mathbb{R}^3$ are addressed where the scalar potential of an associated vector field satisfies Laplace's equation in some unbounded external region and is to be approximated by unknown (point) sources contained in the complimentary subregion. Two specific field geometries are considered: $\\mathbb{R}^3$ half-space and the exterior of an $\\mathbb{R}^3$ sphere, which are the two standard settings for geophysical and geoexploration gravitational problems. For these geometries it is shown that a new type of kernel space exists, which is labeled a Dirichlet-integral dual-access collocation-kernel space (DIDACKS) and that is well suited for many applications. The DIDACKS examples studied are related to reproducing kernel Hilbert spaces and they have a replicating kernel (as opposed to a reproducing kernel) that has the ubiquitous form of the inverse of the distance between a field point and a corresponding source point. Underpinning this approach are three basic mathematical relationships of general int...

  5. Active induction balance method for metal detector sensing head utilizing transmitter-bucking and dual current source

    Science.gov (United States)

    Ambruš, D.; Vasić, D.; Bilas, V.

    2013-06-01

    A central problem in a design of frequency domain electromagnetic induction sensors used in landmine detection is an effective suppression of a direct inductive coupling between the transmitter and the receiver coil (induction balance, IB). In sensing heads based on the transmitter-bucking configuration, IB is achieved by using two concentric transmitter coils with opposing exciter fields in order to create a central magnetic cavity for the receiver coil. This design has numerous advantages over other IB methods in terms of detection sensitivity, spatial resolution, sensor dimensions and suitability for model-based measurements. However, very careful design and precise sensing head geometry are required if a single excitation source is used for driving both transmitter coils. In this paper we analyze the IB sensitivity to small perturbations of geometrical properties of coils. We propose a sensor design with dual current source and active induction balance scheme which overcomes the limitations of geometry-based balancing and potentially provides more efficient compensation of soil effects.

  6. Assessment of aortic stenosis after aortic valve replacement. Comparative evaluation of dual-source CT and echocardiography; Quantitative Evaluation der Aortenklappenoeffnungsflaeche mit der Dual-Source-CT und Korrelation mit der 2D-Echokardiografie. Initiale Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Saam, T.; Minaifar, N.; Becker, C.; Reiser, M.; Nikolaou, K. [Ludwig-Maximilians-Univ. Muenchen (Germany). Inst. fuer Klinische Radiologie; Oberhoffer, M.; Rist, C.; Vogt, F.; Reichart, B. [Ludwig-Maximilians-Univ. Muenchen (Germany). Herzchirurgische Klinik und Poliklinik

    2008-06-15

    Purpose: To prospectively evaluate whether planimetric measurements of aortic valve area (AVA) with dual-source computed tomography (DSCT) correlate with measurements obtained by echocardiography and to correlate the amount of calcification of the aortic valve with AVA in a group of patients after aortic valve replacement. Materials and Method: 23 patients underwent dual-source computed tomography (DSCT) of the heart (Somatom Definition, Siemens Medical Solutions, Forchheim, Germany), without heart rate control (heart rate 52-113 beats/minute). All patients had undergone aortic valve replacement (homografts, mean time after surgery: 7{+-}3 years). The AVA of the transplanted aortic valve graft was measured planimetrically by means of DSCT and compared with echocardiography as a standard of reference, to exclude post-surgical restenosis of the valve. Maximum AVA in systole planimetrically measured with CT was compared with calculated AVA values determined with the continuity equation, using transvalvular pressure gradients. The amount of calcification of the aortic valve was quantified and correlated (Spearman's R) with the AVA. To assess intra- and inter-reader reproducibility, the DCST data was re-analyzed by two readers 4 weeks after the initial review. Results: All DSCT datasets were of diagnostic image quality concerning valve depiction. The mean AVA as measured by DSCT was 2.7{+-}0.9 cm{sup 2} compared to 1.8{+-}0.5 cm{sup 2} by echocardiography (p<0.05). The planimetric evaluation of the CT data as compared to results of echocardiography showed a significant correlation of the results (Pearson's correlation coefficient R=0.78, p<0.001). Intra- and inter-reader reproducibility was good with intra-class correlation coefficients of 0.86 and 0.81, respectively (p<0.001). There was a significant negative correlation between the amount of aortic valve calcification and AVA as measured by echocardiography (R=-0.42; p<0.05) and as measured by DSCT (R=-0

  7. Assessment of vascular contrast and wall motion of the aortic root and ascending aorta on MDCT angiography: dual-source high-pitch vs non-gated single-source acquisition schemes

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Jared D.; Seaman, Danielle M.; Lungren, Matthew P.; Hurwitz, Lynne M.; Boll, Daniel T. [Duke University Medical Center, Department of Radiology, Durham, NC (United States)

    2014-05-15

    This retrospective study assessed whether dual-source high-pitch computed tomographic angiography (CTA) offered advantages over single-source standard-pitch techniques in the evaluation of the ascending aorta. Twenty patients who received both thoracic dual-source high-pitch and single-source standard-pitch CTAs within 1 year were assessed. Dual-source CTAs were performed; standard-pitch imaging used dose-modulated 120 kVp/150 mAs and 0.8 pitch compared with high-pitch protocols employing dose-modulated 120 kVp/250 mAs and 2.4 target pitch. Radiation dose was documented. Contrast-to-noise ratios (CNRs) at sinuses of the Valsalva (CNR{sub Valsalva}) and ascending aorta (CNR{sub Aorta}) were calculated. Dose/CNR for each technique was compared with paired t-tests. Motion at aortic valve, aortic root and ascending aorta were assessed with four-point scales and Mann-Whitney U tests; longitudinal extension of motion was compared with paired t-tests. Significantly lower motion scores for high-pitch, compared with standard-pitch acquisitions for aortic annulus, 0 vs. 2, aortic root, 0 vs. 3, and ascending aorta, 0 vs. 2, were achieved. Significantly reduced longitudinal extension of motion at aortic root, 4.9 mm vs 15.7 mm, and ascending aorta, 4.9 mm vs 21.6 mm, was observed. Contrast was not impacted: CNR{sub Valsalva}, 45.6 vs 46.3, and CNR{sub Aorta}, 45.3 vs 47.1. CTDI{sub vol} was significantly decreased for high-pitch acquisitions, 13.9 mGy vs 15.8 mGy. Dual-source high-pitch CTAs significantly decreased motion artefact without negatively impacting vascular contrast and radiation dose. circle Dual-source high-pitch CTA significantly decreased motion artefact of the ascending aorta. circle Dual-source high-pitch CTA did not negatively impact on vascular contrast. circle Dual-source high-pitch CTA significantly decreased radiation dose compared with single-source standard-pitch acquisitions. (orig.)

  8. Development of an ultra-widely tunable DFG-THz source with switching between organic nonlinear crystals pumped with a dual-wavelength BBO optical parametric oscillator.

    Science.gov (United States)

    Notake, Takashi; Nawata, Kouji; Kawamata, Hiroshi; Matsukawa, Takeshi; Qi, Feng; Minamide, Hiroaki

    2012-11-01

    We developed a difference frequency generation (DFG) source with an organic nonlinear optical crystal of DAST or BNA selectively excited by a dual-wavelength β-BaB(2)O(4) optical parametric oscillator (BBO-OPO). The dual-wavelength BBO-OPO can independently oscillate two lights with different wavelengths from 800 to 1800 nm in a cavity. THz-wave generation by using each organic crystal covers ultrawide range from 1 to 30 THz with inherent intensity dips by crystal absorption modes. The reduced outputs can be improved by switching over the crystals with adequately tuned pump wavelengths of the BBO-OPO.

  9. Evaluation of Wall Boundary Conditions for Impedance Eduction Using a Dual-Source Method

    Science.gov (United States)

    Watson, W. R.; Jones, M. G.

    2012-01-01

    The accuracy of the Ingard-Myers boundary condition and a recently proposed modified Ingard-Myers boundary condition is evaluated for use in impedance eduction under the assumption of uniform mean flow. The evaluation is performed at three centerline Mach numbers, using data acquired in a grazing flow impedance tube, using both upstream and downstream propagating sound sources, and on a database of test liners for which the expected behavior of the impedance spectra is known. The test liners are a hard-wall insert consisting of 12.6 mm thick aluminum, a linear liner without a facesheet consisting of a number of small diameter but long cylindrical channels embedded in a ceramic material, and two conventional nonlinear liners consisting of a perforated facesheet bonded to a honeycomb core. The study is restricted to a frequency range for which only plane waves are cut on in the hard-wall sections of the flow impedance tube. The metrics used to evaluate each boundary condition are 1) how well it educes the same impedance for upstream and downstream propagating sources, and 2) how well it predicts the expected behavior of the impedance spectra over the Mach number range. The primary conclusions of the study are that the same impedance is educed for upstream and downstream propagating sources except at the highest Mach number, that an effective impedance based on both the upstream and downstream measurements is more accurate than an impedance based on the upstream or downstream data alone, and that the Ingard-Myers boundary condition with an effective impedance produces results similar to that achieved with the modified Ingard-Myers boundary condition.

  10. Tracing the Nitrate Sources of the Yili River in the Taihu Lake Watershed: A Dual Isotope Approach

    Directory of Open Access Journals (Sweden)

    Haiao Zeng

    2014-12-01

    Full Text Available As the third largest freshwater lake in China, Taihu Lake has experienced severe cyanobacterial blooms and associated water quality degradation in recent decades, threatening the human health and sustainable development of cities in the watershed. The Yili River is a main river of Taihu Lake, contributing about 30% of the total nitrogen load entering the lake. Tracing the nitrate sources of Yili River can inform the origin of eutrophication in Taihu Lake and provide hints for effective control measures. This paper explored the nitrate sources and cycling of the Yili River based on dual nitrogen (δ15N and oxygen (δ18O isotopic compositions. Water samples collected during both the wet and dry seasons from different parts of the Yili River permitted the analysis of the seasonal and spatial variations of nitrate concentrations and sources. Results indicated that the wet season has higher nitrate concentrations than the dry season despite the stronger dilution effects, suggesting a greater potential of cyanobacterial blooms in summer. The δ15N-NO3− values were in the range of 4.0‰–14.0‰ in the wet season and 4.8‰–16.9‰ in dry, while the equivalent values of δ18O were 0.5‰–17.8‰ and 3.5‰–15.6‰, respectively. The distribution of δ15N-NO3− and δ18O-NO3− indicated that sewage and manure as well as fertilizer and soil organic matter were the major nitrate sources of the Yili River. Atmospheric deposition was an important nitrate source in the upper part of Yili River but less so in the middle and lower reaches due to increasing anthropogenic contamination. Moreover, there was a positive relationship between δ18O-NO3− and δ15N-NO3− in the wet season, indicating a certain extent of denitrification. In contrast, the δ18O-δ15N relationship in the dry season was significantly negative, suggesting that the δ15N and δ18O values were determined by a mixing of different nitrate sources.

  11. First experience with single-source dual-energy computed tomography in six patients with acute arthralgia: a feasibility experiment using joint aspiration as a reference

    Energy Technology Data Exchange (ETDEWEB)

    Diekhoff, Torsten; Kiefer, Tobias; Hamm, Bernd; Hermann, Kay-Geert A. [Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Department of Radiology, Berlin (Germany); Ziegeler, Katharina; Feist, Eugen [Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Department of Rheumatology and Clinical Immunology, Berlin (Germany); Mews, Juergen [Toshiba Medical Systems Europe, BV, Zoetermeer (Netherlands)

    2015-11-15

    Dual-energy computed tomography (DECT) is an emerging imaging technique for examining patients with suspected gout. Single-source dual-energy CT (S-DECT) is a new way of obtaining DECT information on conventional CT scanners rather than using special dual-source CT systems. We tested the feasibility of S-DECT (320-row CT; Aquilion ONE, Toshiba Medical Systems, Otawara, Japan) in 6 patients (5 men, 1 woman; mean age 61.3, range 48 to 69 years) with acute arthralgia and suspected gout, and compared the S-DECT findings with the results of joint aspiration. Three patients had a diagnosis of gouty arthritis with negatively birefringent crystals in synovial fluid, in addition to gouty tophi in S-DECT. Three patients had no detectable crystals by polarization microscopy and no tophi on DECT. Their final diagnoses were rheumatoid arthritis, activated osteoarthritis, and septic arthritis in one case each. This initial experience suggests that S-DECT might be a valuable alternative to dual-source CT. Hence, more patients may benefit from its additional diagnostic abilities in the future. (orig.)

  12. Simultaneous detection of polar and nonpolar compounds by ambient mass spectrometry with a dual electrospray and atmospheric pressure chemical ionization source.

    Science.gov (United States)

    Cheng, Sy-Chyi; Jhang, Siou-Sian; Huang, Min-Zong; Shiea, Jentaie

    2015-02-03

    A dual ionization source combining electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) was developed to simultaneously ionize both polar and nonpolar compounds. The source was constructed by inserting a fused silica capillary into a stainless steel column enclosed in a glass tube. A high dc voltage was applied to a methanol solution flowing in the fused silica capillary to generate an ESI plume at the capillary tip. A high ac voltage was applied to a ring electrode attached to the glass tube to generate plasma from the nitrogen gas flowing between the glass tube and the stainless steel column. The concentric arrangement of the ESI plume and the APCI plasma in the source ensured that analytes entering the ionization region interacted with both ESI and APCI primary ion species generated in the source. Because the high voltages required for ESI and APCI were independently applied and controlled, the dual ion source could be operated in ESI-only, APCI-only, or ESI+APCI modes. Analytes were introduced into the ESI and/or APCI plumes by irradiating sample surfaces with a continuous-wavelength laser or a pulsed laser beam. Analyte ions could also be produced by directing the dual ESI+APCI source toward sample surfaces for desorption and ionization. The ionization mechanisms involved in the dual ion source include Penning ionization, ion molecule reactions, and fused-droplet electrospray ionization. Standards of polycyclic aromatic hydrocarbons, angiotensin I, lidocaine, ferrocene, diesel, and rosemary oils were used for testing. Protonated analyte ions were detected in ESI-only mode, radical cations were detected in APCI-only mode, and both types of ions were detected in ESI+APCI mode.

  13. Assessment of radiation exposure on a dual-source computed tomography-scanner performing coronary computed tomography-angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kirchhoff, S., E-mail: sonja.kirchhoff@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Herzog, P., E-mail: peter.herzog@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Johnson, T., E-mail: Thorsten.johnson@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Boehm, H., E-mail: holger.boehm@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Nikolaou, K., E-mail: konstantin.nikolaou@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Reiser, M.F., E-mail: maximilian.reiser@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Becker, C.H., E-mail: christoph.becker@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany)

    2010-06-15

    Objective: The radiation exposure of a dual-source-64-channel multi-detector-computed-tomography-scanner (Somatom-Defintion, Siemens, Germany) was assessed in a phantom-study performing coronary-CT-angiography (CTCA) in comparison to patients' data randomly selected from routine scanning. Methods: 240 CT-acquisitions of a computed tomography dose index (CTDI)-phantom (PTW, Freiburg, Germany) were performed using a synthetically generated Electrocardiography (ECG)-signal with variable heart rates (30-180 beats per minute (bpm)). 120 measurements were acquired using continuous tube-output; 120 measurements were performed using ECG-synchronized tube-modulation. The pulsing window was set at minimum duration at 65% of the cardiac cycle between 30 and 75 bpm. From 90-180 bpm the pulsing window was set at 30-70% of the cardiac cycle. Automated pitch adaptation was always used. A comparison between phantom CTDI and two patient groups' CTDI corresponding to the two pulsing groups was performed. Results: Without ECG-tube-modulation CDTI-values were affected by heart-rate-changes resulting in 85.7 mGray (mGy) at 30 and 45 bpm, 65.5 mGy/60 bpm, 54.7 mGy/75 bpm, 46.5 mGy/90 bpm, 34.2 mGy/120 bpm, 27.0 mGy/150 bpm and 22.1 mGy/180 bpm equal to effective doses between 14.5 mSievert (mSv) at 30/45 bpm and 3.6 mSv at 180 bpm. Using ECG-tube-modulation these CTDI-values resulted: 32.6 mGy/30 bpm, 36.6 mGy/45 bpm, 31.4 mGy/60 bpm, 26.8 mGy/75 bpm, 23.7 mGy/90 bpm, 19.4 mGy/120 bpm, 17.2 mGy/150 bpm and 15.6 mGy/180 bpm equal to effective doses between 5.5 mSv at 30 bpm and 2.6 mSv at 180 bpm. Significant CTDI-differences were found between patients with lower/moderate and higher heart rates in comparison to the phantom CTDI-results. Conclusions: Dual source CTCA is particularly dose efficient at high heart rates when automated pitch adaptation, especially in combination with ECG-based tube-modulation is used. However in clinical routine scanning for patients with higher

  14. Image Quality and Radiation Dose for Prospectively Triggered Coronary CT Angiography: 128-Slice Single-Source CT versus First-Generation 64-Slice Dual-Source CT

    Science.gov (United States)

    Gu, Jin; Shi, He-Shui; Han, Ping; Yu, Jie; Ma, Gui-Na; Wu, Sheng

    2016-10-01

    This study sought to compare the image quality and radiation dose of coronary computed tomography angiography (CCTA) from prospectively triggered 128-slice CT (128-MSCT) versus dual-source 64-slice CT (DSCT). The study was approved by the Medical Ethics Committee at Tongji Medical College of Huazhong University of Science and Technology. Eighty consecutive patients with stable heart rates lower than 70 bpm were enrolled. Forty patients were scanned with 128-MSCT, and the other 40 patients were scanned with DSCT. Two radiologists independently assessed the image quality in segments (diameter >1 mm) according to a three-point scale (1: excellent; 2: moderate; 3: insufficient). The CCTA radiation dose was calculated. Eighty patients with 526 segments in the 128-MSCT group and 544 segments in the DSCT group were evaluated. The image quality 1, 2 and 3 scores were 91.6%, 6.9% and 1.5%, respectively, for the 128-MSCT group and 97.6%, 1.7% and 0.7%, respectively, for the DSCT group, and there was a statistically significant inter-group difference (P ≤ 0.001). The effective doses were 3.0 mSv in the 128-MSCT group and 4.5 mSv in the DSCT group (P ≤ 0.001). Compared with DSCT, CCTA with prospectively triggered 128-MSCT had adequate image quality and a 33.3% lower radiation dose.

  15. Diagnostic accuracy of dual-source CT coronary angiography with prospective ECG-triggering on different heart rate patients

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Ming-li; Lu, Bin; Han, Lei; Liu, Gang; Yu, Fang-Fang; Hou, Zhi-hui; Gao, Yang; Wang, Hong-yu; Jiang, Shiliang [Peking Union Medical College, Department of Radiology, Cardiovascular Institute and Fu Wai Hospital, Chinese Academy of Medical Sciences, Beijing (China); Wu, Run-ze; Johnson, Laura [CT Research Collaboration, Siemens Healthcare, Shang Hai (China); Yang, Yue-jin; Qiao, Shu-bin [Chinese Academy of Medical Sciences, Peking Union Medical College, Department of Cardiology, Division of Coronary Heart Disease, Cardiovascular Institute and Fu Wai Hospital, Beijing (China)

    2011-08-15

    To evaluate the diagnostic accuracy of dual-source CT (DSCT) prospective ECG-triggering coronary angiography in patients with different heart rate (HR). 103 patients with suspected coronary artery disease underwent DSCT prospective ECG-triggered coronary angiography and invasive coronary angiography (ICA). The patients were grouped by HR during CT scans: low HR ({<=}60 bpm, n = 34); medium HR (60 < HR {<=} 70 bpm, n = 36) and high HR (>70 bpm, n = 33). The sensitivity and specificity of DSCT in detecting {>=}50% stenosis were compared among subgroups where ICA was the gold standard. Image quality was scored using a 4-point scale. A total of 1,580 (95.9%) coronary artery segments were evaluable. Sensitivity and specificity were 82.8% and 98.4%, 88.3% and 98.7%, and 80.3% and 98.6% for different subgroups (all p > 0.05). The overall area under the curve of the receiver-operating characteristic analysis was 0.94. The image quality scores were 3.1 {+-} 0.3, 3.1 {+-} 0.3 and 3.0 {+-} 0.4 for subgroups (p > 0.05). The overall average effective radiation dose was 3.60 {+-} 1.60 mSv. DSCT coronary angiography with prospective ECG-triggering could be just as accurate in patients with medium to high HR compared to those with low HR. (orig.)

  16. Systolic prospectively ECG-triggered dual-source CT angiography for evaluation of the coronary arteries in heart transplant recipients

    Energy Technology Data Exchange (ETDEWEB)

    Bastarrika, Gorka [Clinica Universidad de Navarra, Cardiac Imaging Unit, Pamplona (Spain); Clinica Universidad de Navarra, Department of Radiology, Pamplona (Spain); Broncano, Jordi; Arraiza, Maria; Simon-Yarza, Isabel; Pueyo, Jesus C.; Zubieta, Jose L. [Clinica Universidad de Navarra, Department of Radiology, Pamplona (Spain); Azcarate, Pedro M. [Clinica Universidad de Navarra, Cardiac Imaging Unit, Pamplona (Spain); Clinica Universidad de Navarra, Department of Cardiology, Pamplona (Spain); Levy Praschker, Beltran G.; Rabago, Gregorio [Clinica Universidad de Navarra, Department of Cardiovascular Surgery, Pamplona (Spain)

    2011-09-15

    To assess feasibility, image quality, and radiation dose of prospectively ECG-triggered coronary CT angiography (CTA) in orthotopic heart transplant (OHT) recipients. 47 consecutive OHT recipients (40 men, mean age 62.1{+-}10.9 years, mean heart rate 86.3{+-}14.4 bpm) underwent dual-source CTA to rule out coronary allograft vasculopathy in a prospectively ECG-triggered mode with data acquisition during 35% to 45% of the cardiac cycle. Two independent observers blindly assessed image quality on a per-segment and per-vessel basis using a four-point scale (1-excellent, 4-not evaluable). Scores 1-3 were considered acceptable for diagnosis. Multivariate analysis was performed to evaluate differences between image quality scores obtained at different reconstruction intervals. Effective radiation doses were calculated. 671 coronary segments were evaluated. Interobserver agreement on the image quality was {kappa}=0.75. Diagnostic image quality was observed in 93.9%, 95.5% and 93.3% of the segments at 35%, 40% and 45% reconstruction intervals. Mean image quality score was 1.5{+-}0.7 for the entire coronary tree, 1.4{+-}0.7 for the RCA, 1.6{+-}0.8 for the LCA and 1.6{+-}0.7 for the Cx at the best reconstruction interval. Estimated mean radiation dose was 4.5{+-}1.2 mSv. Systolic prospectively ECG-triggered CTA allows diagnostic image quality coronary angiograms in OHT recipients at low radiation doses. (orig.)

  17. Detection of Special Nuclear Material from Delayed Neutron Emission Induced by a Dual-Particle Monoenergetic Source

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Michael F.; Nattress, J.; Jovanovic, I

    2016-06-30

    Detection of unique signatures of special nuclear materials is critical for their interdiction in a variety of nuclear security and nonproliferation scenarios. We report on the observation of delayed neutrons from fission of uranium induced in dual-particle active interrogation based on the 11B(d,n gamma)12C nuclear reaction. Majority of the fissions are attributed to fast fission induced by the incident quasi-monoenergetic neutrons. A Li-doped glass–polymer composite scintillation neutron detector, which displays excellent neutron/γ discrimination at low energies, was used in the measurements, along with a recoil-based liquid scintillation detector. Time- dependent buildup and decay of delayed neutron emission from 238U were measured between the interrogating beam pulses and after the interrogating beam was turned off, respectively. Characteristic buildup and decay time profiles were compared to the common parametrization into six delayed neutron groups, finding a good agreement between the measurement and nuclear data. This method is promising for detecting fissile and fissionable materials in cargo scanning applications and can be readily integrated with transmission radiography using low-energy nuclear reaction sources.

  18. Automated attenuation-based tube voltage selection for body CTA: Performance evaluation of 192-slice dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Winklehner, Anna; Gordic, Sonja; Lauk, Eliane; Frauenfelder, Thomas; Alkadhi, Hatem; Husarik, Daniela B. [University Hospital Zurich, Institute for Diagnostic and Interventional Radiology, Zurich (Switzerland); Leschka, Sebastian [University Hospital Zurich, Institute for Diagnostic and Interventional Radiology, Zurich (Switzerland); Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland)

    2015-08-15

    To assess radiation dose and image quality in body CT-angiography (CTA) with automated attenuation-based tube voltage selection (ATVS) on a 192-slice dual-source CT (DSCT). Forty patients (69.5 ± 9.6 years) who had undergone body CTA with ATVS (ref.kVp 100, ref.mAs 90) using a 2x192-slice CT in single-source mode were retrospectively included. All patients had undergone prior CTA with a 2x128-slice CT and ATVS with identical imaging and contrast media protocols, serving for comparison. Images were reconstructed with iterative reconstruction at similar strength levels. Radiation dose was determined. Image quality was assessed semi-quantitatively (1:excellent, 5:non-diagnostic), aortic attenuation, noise and CNR were determined. As compared to 128-slice DSCT, 192-slice DSCT selected tube voltages were lower in 30 patients (75 %), higher in 3 (7.5 %), and similar in 7 patients (17.5 %). CTDI{sub vol} was lower with 192-slice DSCT (4.7 ± 1.9 mGy vs. 5.8 ± 2.1 mGy; p < 0.001). Subjective image quality, mean aortic attenuation (342 ± 67HU vs. 268 ± 67HU) and CNR (9.8 ± 2.5 vs. 8.2 ± 2.9) were higher with 192-slice DSCT (all p < 0.01), all datasets being diagnostic. Our study suggests that ATVS of 192-slice DSCT for body CTA is associated with an improved image quality and further radiation dose reduction of 19 % compared to 128-slice DSCT. (orig.)

  19. A dual-energy medical instrument for measurement of x-ray source voltage and dose rate

    Science.gov (United States)

    Ryzhikov, V. D.; Naydenov, S. V.; Volkov, V. G.; Opolonin, O. D.; Makhota, S.; Pochet, T.; Smith, C. F.

    2016-03-01

    An original dual-energy detector and medical instrument have been developed to measure the output voltages and dose rates of X-ray sources. Theoretical and experimental studies were carried out to characterize the parameters of a new scintillator-photodiode sandwich-detector based on specially-prepared zinc selenide crystals in which the low-energy detector (LED) works both as the detector of the low-energy radiation and as an absorption filter allowing the highenergy fraction of the radiation to pass through to the high-energy detector (HED). The use of the LED as a low-energy filter in combination with a separate HED opens broad possibilities for such sandwich structures. In particular, it becomes possible to analyze and process the sum, difference and ratio of signals coming from these detectors, ensuring a broad (up to 106) measurement range of X-ray intensity from the source and a leveling of the energy dependence. We have chosen an optimum design of the detector and the geometry of the component LED and HED parts that allow energy-dependence leveling to within specified limits. The deviation in energy dependence of the detector does not exceed about 5% in the energy range from 30 to 120 keV. The developed detector and instrument allow contactless measurement of the anode voltage of an X-ray emitter from 40 to 140 kV with an error no greater than 3%. The dose rate measurement range is from 1 to 200 R/min. An original medical instrument has passed clinical testing and was recommended for use in medical institutions for X-ray diagnostics.

  20. High-pitch dual-source CT angiography of supra-aortic arteries: assessment of image quality and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Korn, A.; Fenchel, M.; Bender, B.; Danz, S.; Ernemann, U. [Department of Diagnostic und Interventional Neuroradiology, Tuebingen (Germany); Thomas, C.; Ketelsen, D.; Claussen, C.D.; Heuschmid, M. [Department of Diagnostic und Interventional Radiology, Tuebingen (Germany); Moonis, G. [Beth Israel Deaconess Medical Center, Department of Radiology, Boston, MA (United States); Krauss, B. [Siemens AG, Imaging and Therapy Division, Forchheim (Germany); Brodoefel, H. [Department of Diagnostic und Interventional Radiology, Tuebingen (Germany); Beth Israel Deaconess Medical Center, Department of Radiology, Boston, MA (United States); Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA (United States)

    2013-04-15

    High-pitch CT angiography (CTA) is a recent innovation that allows significant shortening of scan time with volume coverage of 43 mm per second. The aim of our study was to assess this technique in CTA of the head and neck. CTA of supra-aortic arteries was performed in 50 patients using two acquisition protocols: conventional single-source 64-slice (pitch 1.2) and high-pitch dual-source 128-slice CT (pitch 3.2). Subjective and objective image quality of supra-aortic vessel ostia as well as intra- and extra-cranial segments was retrospectively assessed by blinded readers and radiation dose compared between the two protocols. Conventional and high-pitch CTA achieved comparable signal-to-noise ratios in arterial (54.3 {+-} 16.5 versus 57.3 {+-} 14.8; p = 0.50) and venous segments (15.8 {+-} 6.7 versus 18.9 {+-} 8.9; p = 0.21). High-pitch scanning was, however, associated with sharper delineation of vessel contours and image quality significantly improved at the level of supra-aortic vessel ostia (p < 0.0001) as well as along the brachiocephalic trunk (p < 0.0001), the subclavian arteries (p < 0.0001), proximal common carotid arteries (p = 0.01), and vertebral V1 segments (p < 0.0001). Using the high-pitch mode, the dose-length product was reduced by about 35 % (218.2 {+-} 30 versus 141.8 {+-} 20 mGy x cm). Due to elimination of transmitted cardiac motion, high-pitch CTA of the neck improves image quality in the proximity of the aortic arch while significantly lowering radiation dose. The technique thus qualifies as a promising alternative to conventional spiral CTA and may be particularly useful for identification of ostial stenosis. (orig.)

  1. Diagnostic accuracy of dual-source CT coronary angiography: The effect of average heart rate, heart rate variability, and calcium score in a clinical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Long-Jiang Zhang; Zhuo-Li Zhang; Chang-Sheng Zhou; Guang-Ming Lu (Dept. of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing Univ., Nanjing (China)), e-mail: cjr.luguangming@vip.163.com; Sheng-Yong Wu (Medical Imaging Inst. of Tianjin, Tianjin (China)); Jing Wang; Shi-Sen Jiang (Dept. of Cardiology, Jinling Hospital, Clinical School of Medical College, Nanjing Univ., Nanjing (China)); Ying Lu (Dept. of Radiology and Biomedical Imaging, Univ. of California, San Francisco, CA (United States))

    2010-09-15

    Background: Dual-source CT coronary angiography (CTCA) has been used to detect coronary artery disease; however, the factors with potential to affect its diagnostic accuracy remain to be defined. Purpose: To prospectively evaluate the accuracy of dual-source CTCA in diagnosing coronary artery stenosis according to conventional coronary angiography (CAG), and the effect of average heart rate, heart rate variability, and calcium score on the accuracy of CTCA. Material and Methods: A total of 113 patients underwent both dual-source CTCA and CAG. The results were used to evaluate the findings in dual-source CTCA to assess the accuracy in the diagnosis of =50% (significant stenosis) and >75% (severe stenosis) of coronary artery according to those by CAG. Patients were divided into subgroups according to their heart rate (HR), HR variability (HRV), and calcium score, and the accuracy of CTCA was further evaluated. The chi-square test was used to analyze the difference in sensitivity and specificity for the detection of =50% and >75% coronary stenosis among subgroups. The generalized estimation equation method was used in per-vessel analysis to adjust for within-patient correlation. Results: In all, 113 patients had 338 vessels and 1661 segments evaluated by CAG. Dual-source CTCA displayed 1527 segments (91.9%). Among them, 1468 segments (calcium score by CAG score 1, n=1018; score 2, n=270; score 3, n=180) were assessable in CTCA. On a per-patient analysis, the sensitivity and specificity of CTCA were 93.9% and 93.5% for significant stenosis and 86.9% and 98.1% for severe stenosis. On a per-vessel basis, the sensitivity and specificity were 90.2% and 97.1% for significant and 83.3% and 98.1% for severe stenosis. On a per-segment analysis, the sensitivity and specificity were 90.2% and 97.1% for significant and 83.3% and 98.1% for severe stenosis. Average HR had no effect on the sensitivity and specificity of CTCA (P>0.05); whereas HRV and calcium score had some effect on

  2. 双源双能CT在尿路结石成分分析中的应用%Dual source dual energy CT in the analysis of urinary calculi composition

    Institute of Scientific and Technical Information of China (English)

    范璐; 郭君武; 张慧

    2012-01-01

    目的:探讨双源CT双能量技术应用于尿路结石成分分析中的临床价值.方法:226例尿路结石患者行双源CT双能量扫描,对其结石成分进行分析,将结果与用红外光谱法分析结石成分的结果作对比,计算双源CT在体分析草酸钙结石、磷酸盐结石、胱氨酸结石及尿酸结石的灵敏度与特异度.结果:双源CT能够准确的区分尿酸结石和非尿酸结石(灵敏度和特异度均为100%),较准确的区分草酸钙结石(灵敏度为89.03%、特异度为85.62%),磷酸盐结石(灵敏度为67.28%、特异度为90.71%)及胱氨酸结石(灵敏度为73.56%、特异度为93.43%).结论:双源CT双能量技术能在治疗前对尿路结石的成分进行初步分析,对了解结石成因,预防结石形成及指导治疗具有重要的意义.%Objective: To assess the clinical value of dual source dual energy CT in the analysis of urinary calculi composition. Methods:Dual-source CT with dual-energy scanning technique was performed in 226 patients with urinary calculi. The composition of urinary stones was compared with the results of the urinary stones composition analyzed by Fourier transform infrared spectroscopy (FTIR). The sensitivity and specificity of dual energy CT in evaluating the composition of calcium oxalate stone, phosphate stone, cystine stone and uric acid stone in vivo were calculated. Results:Dual-source CT could accurately distinguish uric acid stones and non-uric acid stones with the sensitivity and specificity as 100% respectively. The sensitivity of differentiating calcium oxalate stone, cystine stone and phosphate stone was 89. 3%, 67. 28% and 73. 56% respectively,and the specificity of the above mentioned calculi was 85. 62%,90. 71% and 93. 43% respectively. Conclusion: Analysis of urinary calculi composition before treatment could be obtained by dual-source CT with dual-energy technique, which had significant importance to understand the causes of stone,to prevent

  3. Added value of 80 kVp images to averaged 120 kVp images in the detection of hepatocellular carcinomas in liver transplantation candidates using dual-source dual-energy MDCT: Results of JAFROC analysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Hoon [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Kim, Se Hyung, E-mail: shkim@radcom.snu.ac.kr [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Hospital (Korea, Republic of); Park, Hee Sun [Department of Radiology, Konkuk University Hospital (Korea, Republic of); Kim, Gi Hyeon [Department of Radiology, Chung-Ang University Hospital (Korea, Republic of); Lee, Jae Young; Lee, Jeong Min; Han, Joon Koo; Choi, Byung Ihn [Department of Radiology, Seoul National University Hospital (Korea, Republic of); The Institute of Radiation Medicine, Seoul National University Hospital (Korea, Republic of)

    2011-11-15

    Background: To assess the added value of 80 kVp images to weighted average 120 kVp images for detecting hepatocellular carcinomas (HCCs) using dual-source, dual-energy MDCT. Materials and methods: Forty-one HCCs in 42 patients who underwent liver transplantation (LT) were included. All patients underwent quadruple-phase CT using a 64-row dual-source, dual-energy MDCT with 80 kVp and 140 kVp. For 120 kVp, a linear blending ratio of 0.3 was chosen. Interval reviews for both simulated 120 kVp images without and with pure 80 kVp data were performed independently by two radiologists. They detected HCCs using a 4-point confidence scale. Tumor-to-liver contrast-to-noise ratio (CNR) was calculated and compared between the 80 kVp and simulated 120 kVp images. The additional diagnostic value of 80 kVp images was evaluated by jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis. Results: There were 41 HCCs on pathology and 37 of the 41 HCCs were depicted on CT scan. The mean CNR of the 37 HCCs in late arterial and portal-phase images was significantly better in the 80 kVp images than in 120 kVp images. The average JAFROC figure of merit, however, was not significantly improved when 80 kVp was added. Furthermore, the number of false-positives was significantly increased in reader 1 when adding 80 kVp data. Conclusion: The addition of 80 kVp CT images to simulated 120 kVp images did not significantly improve the detection of HCCs despite of the significantly better CNR of 80 kVp images.

  4. Adenosine receptor control of cognition in normal and disease.

    Science.gov (United States)

    Chen, Jiang-Fan

    2014-01-01

    Adenosine and adenosine receptors (ARs) are increasingly recognized as important therapeutic targets for controlling cognition under normal and disease conditions for its dual roles of neuromodulation as well as of homeostatic function in the brain. This chapter first presents the unique ability of adenosine, by acting on the inhibitory A1 and facilitating A2A receptor, to integrate dopamine, glutamate, and BNDF signaling and to modulate synaptic plasticity (e.g., long-term potentiation and long-term depression) in brain regions relevant to learning and memory, providing the molecular and cellular bases for adenosine receptor (AR) control of cognition. This led to the demonstration of AR modulation of social recognition memory, working memory, reference memory, reversal learning, goal-directed behavior/habit formation, Pavlovian fear conditioning, and effort-related behavior. Furthermore, human and animal studies support that AR activity can also, through cognitive enhancement and neuroprotection, reverse cognitive impairments in animal models of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease, and schizophrenia. Lastly, epidemiological evidence indicates that regular human consumption of caffeine, the most widely used psychoactive drug and nonselective AR antagonists, is associated with the reduced cognitive decline in aging and AD patients, and with the reduced risk in developing PD. Thus, there is a convergence of the molecular studies revealing AR as molecular targets for integrating neurotransmitter signaling and controlling synaptic plasticity, with animal studies demonstrating the strong procognitive impact upon AR antagonism in normal and disease brains and with epidemiological and clinical evidences in support of caffeine and AR drugs for therapeutic modulation of cognition. Since some of adenosine A2A receptor antagonists are already in phase III clinical trials for motor benefits in PD patients with remarkable safety profiles

  5. Evaluation of high-pitch dual-source CT angiography for evaluation of coronary and carotid-cerebrovascular arteries

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kai [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Li, Kuncheng, E-mail: cjr.likuncheng@vip.163.com [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Han, Ruijuan [Department of Cardiology, Chaoyang Hospital, Capital Medical University, Beijing 100020 (China); Li, Wenhuan; Chen, Nan; Yang, Qi; Du, Xiangying; Wang, Chen [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Liu, Guorong; Li, Yuechun [Department of Neurology Baotou Central Hospital, Inner Mongolia, Baotou 014040 (China); Zhou, Maorong [Department of Radiology, Baotou Central Hospital, Inner Mongolia, Baotou 014040 (China); Li, Ligang; Heidrun, Endt [CT BM Clinic Marketing, Siemens Healthcare, Beijing 100102 (China)

    2015-03-15

    Objectives: To explore the feasibility and diagnostic accuracy of a combined one-step high-pitch dual-source computed tomography angiography (CTA) technique for evaluation of coronary and carotid-cerebrovascular arteries. Materials and methods: 85 symptomatic patients suspected of coronary artery and cerebrovascular disease referred for simultaneous coronary and carotid-cerebrovascular CTA were included. Additional invasive angiography of the coronary and cerebral arteries was performed within 30 days in 23 and 13 patients, respectively. The objective parameters of image quality, the mean CT attenuations, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were evaluated. The subjective image quality of vessels was also assessed by 2 independent radiologists blinded to the patients’ medical history and scan protocols. The diagnostic performance of CTA including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the detection or exclusion of significant artery stenosis was calculated using the chi-squared test of contingency and correlated with the results of invasive angiography representing the standard of reference. Results: Image quality was rated excellent (score 1) in 95.3% (1074/1127), good (score 2) in 3.3% (37/1127), adequate (score 3) in 1.0% (11/1127), and non-diagnostic (score 4) in 0.4% (5/1127) of coronary segments. Image quality of carotid and cerebral vessels was rated mostly excellent (score 1, 95.12% [78/82]; score 2, 3.66% [3/82]; score 3, 1.22% [1/82]). The sensitivity, specificity, PPV and NPV for the detection of coronary stenosis were 92.2% (81.1–97.7%), 95.2% (91.7–97.5%), 79.6% (67.1–89.1%) and 98.3% (95.8–99.5%), respectively. For the detection of carotid and cerebral artery stenosis, CTA demonstrated a sensitivity of 92.8% (80.5–98.4%), a specificity of 93.5% (88.3–96.8%), a PPV of 79.6% (65.6–89.7%) and a NPV of 97.9% (94.1–99.5%). The effective

  6. Study on Clinical Application of of the Dual Energy Technique of Dual Source CT in Kidney Lesions%肾脏占位性病变中双源CT双能量技术的应用研究

    Institute of Scientific and Technical Information of China (English)

    马海鸿; 赵波; 周应恩

    2016-01-01

    目的:探究双源CT双能量技术在肾脏占位性病变的临床应用价值。方法选择2012年1月至2014年8月在新疆喀什地区第二人民医院接受治疗的肾脏占位性病变患者78例。分别采用常规CT扫描和双源CT双能量技术的增强扫描。将双源CT增强扫描结果记为观察组,常规CT扫描记为对照组。对比两组扫描图像及CT值,以及辐射剂量。结果观察组所收集的图像92.31%(72/78)的病患大部分能清晰显示,满足医师的诊断要求。并且观察组在各个部位扫描得到的CT值与对照组无显著差异且SNR显著高于对照组,而辐射剂量中的CTDIvoII、DLY以及ED均显著低于对照组。差异均有统计学意义(均P<0.05)。结论采用双源CT双能量技术对肾脏占位性病变进行诊断的图像质量较好,能满足检查的需要。此外,扫描结果中CT值可观、噪声比较低,而且辐射剂量非常低。在临床上具有较高的应用价值,值得推广应用。%Objective To explore the technique of dual source dual energy CT lesions clinical application value in the kidney. Methods 78 cases of renal occupying lesionsin was in the Second People's Hospital of Xinjiang Kashi Region for treatment From January 2012 to August 2014. Enhanced scan were used routine CT scan and dual energy technique of dual source CT. The dual source CT scan results recorded in the observation group, routine CT scan as control group, compared the two groups of images and the CT value, and the radiation dose. Results In the observation group, 92.31%(72/78) the patients of the collected most of the image display, to meet the requirements of medical diagnosis. And the observation group in each part of scanning CT value had no significant difference with control group and SNR was significantly higher than that of control group, and the radiation dose of CTDIvoII, DLY and ED were significantly lower than those of the control group. The differences

  7. Coronary calcium screening with dual-source CT: reliability of ungated, high-pitch chest CT in comparison with dedicated calcium-scoring CT

    Energy Technology Data Exchange (ETDEWEB)

    Hutt, Antoine; Faivre, Jean-Baptiste; Remy, Jacques; Remy-Jardin, Martine [CHRU et Universite de Lille, Department of Thoracic Imaging, Hospital Calmette (EA 2694), Lille (France); Duhamel, Alain; Deken, Valerie [CHRU et Universite de Lille, Department of Biostatistics (EA 2694), Lille (France); Molinari, Francesco [Centre Hospitalier General de Tourcoing, Department of Radiology, Tourcoing (France)

    2016-06-15

    To investigate the reliability of ungated, high-pitch dual-source CT for coronary artery calcium (CAC) screening. One hundred and eighty-five smokers underwent a dual-source CT examination with acquisition of two sets of images during the same session: (a) ungated, high-pitch and high-temporal resolution acquisition over the entire thorax (i.e., chest CT); (b) prospectively ECG-triggered acquisition over the cardiac cavities (i.e., cardiac CT). Sensitivity and specificity of chest CT for detecting positive CAC scores were 96.4 % and 100 %, respectively. There was excellent inter-technique agreement for determining the quantitative CAC score (ICC = 0.986). The mean difference between the two techniques was 11.27, representing 1.81 % of the average of the two techniques. The inter-technique agreement for categorizing patients into the four ranks of severity was excellent (weighted kappa = 0.95; 95 % CI 0.93-0.98). The inter-technique differences for quantitative CAC scores did not correlate with BMI (r = 0.05, p = 0.575) or heart rate (r = -0.06, p = 0.95); 87.2 % of them were explained by differences at the level of the right coronary artery (RCA: 0.8718; LAD: 0.1008; LCx: 0.0139; LM: 0.0136). Ungated, high-pitch dual-source CT is a reliable imaging mode for CAC screening in the conditions of routine chest CT examinations. (orig.)

  8. Imaging of pulmonary vein anatomy using low-dose prospective ECG-triggered dual-source computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Blanke, Philipp; Baumann, Tobias; Langer, Mathias; Pache, Gregor [University Hospital Freiburg, Department of Diagnostic Radiology, Freiburg (Germany)

    2010-08-15

    To prospectively investigate the feasibility, image quality and radiation dose estimates for computed tomography angiography (CTA) of the pulmonary veins and left atrium using prospective electrocardiography (ECG)-triggered sequential dual-source (DS) data acquisition at end-systole in patients with paroxysmal atrial fibrillation undergoing radiofrequency ablation. Thirty-five patients (mean age 66.2 {+-} 12.6 years) with paroxysmal atrial fibrillation underwent prospective ECG-triggered sequential DS-CTA with tube current (250 mAs/rotation) centred 250 ms past the R-peak. Tube voltage was adjusted to the BMI (<25 kg/m{sup 2}: 100 kV, >25 kg/m{sup 2}: 120 kV). Presence of motion or stair-step artefacts was assessed. Effective radiation dose was calculated from the dose-length product. All data sets could be integrated into the electroanatomical mapping system. Twenty-two patients (63%) were in sinus rhythm (mean heart rate 69.2 {+-} 11.1 bpm, variability 1.0 {+-} 1.7 bpm) and 13 (37%) showed an ECG pattern of atrial fibrillation (mean heart rate 84.8 {+-} 16.6 bpm, variability 17.9 {+-} 7.5 bpm). Minor step artefacts were observed in three patients (23%) with atrial fibrillation. Mean estimated effective dose was 1.1 {+-} 0.3 and 3.0 {+-} 0.5 mSv for 100 and 120 kV respectively. Imaging of pulmonary vein anatomy is feasible using prospective ECG-triggered sequential data acquisition at end-systole regardless of heart rate or rhythm at the benefit of low radiation dose. (orig.)

  9. Effect of age and plaque morphology on diagnostic accuracy of dual source multidetector computed tomography coronary angiography

    Institute of Scientific and Technical Information of China (English)

    Hamza Sunman; Giray Kabak; Lale Tokgzolu; Ali Oto; Kudret Aytemir; Hikmet Yorgun; Uur Canpolat; Ali Taher; Edis Demiri; Tuncay Hazrolan; Leventahiner; Ergn B.Kaya

    2014-01-01

    Background Multidetector computed tomography (MDCT) coronary angiography represents one of the most exciting technological revolutions in cardiac imaging and it has been increasingly used in the diagnosis of coronary artery disease. The purpose of this study is to investigate the effect of age and coronary plaque calcification on diagnostic accuracy of MDCT. Methods The patients were examined by using dual-source MDCT and conventional coronary angiography. MDCT results were analyzed with regard to the severity (>50%stenosis) and morphology (non-calcified, mixed, or calcified) of coronary atherosclerotic plaques evaluated in a 16-segment model. Results In total, 181 patients (94 men and 87 women) with 2,687 coronary artery segments were examined with MDCT. Ninety three patients were older than 65 years of age (group A, 42 men) and 88 were younger (group B, 52 men). Two-hundred nine coronary artery segments (7.2%) were ex-cluded because of small distal coronary vessel segments and/or motion artifacts. The overall number of segments with non-diagnostic image quality was similar in both groups of patients. Of the 2,687 evaluated segments, 157 (5.8%) were significantly diseased, and 144 of them were correctly detected by MDCT. Diagnostic evaluation showed that the sensitivity, positive predictive value, specificity, and negative pre-dictive value were 89.5%, 62.5%, 96.0%, and 99.2%, respectively in group A, and 95.2%, 64.8%, 97.5%, and 99.8%in group B, respectively. In addition, detailed segment-based analyses in coronary segments with non-calcified, mixed and calcified plaques in both groups were simi-lar diagnostic accuracy. Conclusions Very high diagnostic accuracy observed in this study suggests that MDCT coronary angiography could be a suitable diagnostic tool for not only younger patients but also for older patients.

  10. Influence of energy density of different light sources on knoop hardness of a dual-cured resin cement

    Directory of Open Access Journals (Sweden)

    Evandro Piva

    2008-06-01

    Full Text Available The purpose of this study was to evaluate the Knoop hardness of a dual-cured resin-based luting cement irradiated with different light sources as well energy density through a ceramic sample. Three light-curing unit (LCUs were tested: tungsten halogen light (HAL, light-emitting diode (LED and xenon plasma-arc (PAC lamp. Disc-shaped specimens were fabricated from a resin-based cement (Enforce. Three energy doses were used by modifying the irradiance (I of each LCU and the irradiation time (T: 24 Jcm-2 (I/2x2T, 24 Jcm-2 (IxT and 48 Jcm-2 (Ix2T. Energy doses were applied through a 2.0-mm-thick ceramic sample (Duceram Plus. Three groups underwent direct irradiation over the resin cement with the different LCUs and a chemically-activated group served as a control. Thirteen groups were tested (n=10. Knoop hardness number (KHN means were obtained from cross-sectional areas. Two-way ANOVA and the Holm-Sidak method were used for statistical comparisons of activation mode and energy doses (a=5%. Application of 48 J.cm-2 energy dose through the ceramic using LED (50.5±2.8 and HAL (50.9±3.7 produced significantly higher KHN means (p<0.05 than the control (44.7±3.8. LED showed statistically similar performance to HAL. Only HAL showed a relationship between the increase of LCU energy dose and hardness increase.

  11. Comparison of low-dose sequences of dual-source CT and echocardiography for preoperative evaluation of aortic valve disease

    Institute of Scientific and Technical Information of China (English)

    FENG Juan; WANG Xi-ming; JI Xiao-peng; LI Hai-ou; LI Qiao; GUO Wen-bin; WANG Zheng-jun

    2013-01-01

    Background Accurate evaluation of coronary artery,aortic valve annulus diameter (AVAD),and cardiac function in patients with aortic valve disease is of great significance for surgical strategy.In this study,we explored the preoperative evaluation of low-dose sequence (MinDose sequence) scan of dual-source CT (DSCT) for those patients.Methods Forty patients suspected for aortic valve disease (the experimental group) underwent MinDose sequence of DSCT to observe coronary artery,AVAD,and left ventricular ejection fraction (LVEF).Another 33 subjects suspected for coronary artery disease (the control group) underwent conventional retrospective electrocardiographically-gated sequence of DSCT.Two-dimensional transthoracic echocardiography (2D-TTE) and four-dimensional transthoracic echocardiography (4D-TTE) were applied in the experimental group to measure AVAD and LVEF and compared with MinDose-DSCT.Results There was a strong correlation between LVEFs measured by 2D-TTE and MinDose-DSCT (r=0.87,P <0.01),as well as between 4D-TTE and MinDose-DSCT (r=0.90,P <0.01).AVAD measured by MinDose-DSCT was in good agreement with corresponding measurements by 2D-TTE (r=0.90,P <0.01).The effective dose in the experimental group was 63.54% lower than that in the control group.Conclusions MinDose sequence of DSCT with a low radiation dose serving as a one-stop preoperative evaluation makes effective assessment of the coronary artery,AVAD,and LVEF for patients with aortic valve disease.

  12. Pathologic overproduction: the bad side of adenosine.

    Science.gov (United States)

    Borea, Pier Andrea; Gessi, Stefania; Merighi, Stefania; Vincenzi, Fabrizio; Varani, Katia

    2017-03-02

    Adenosine is an endogenous ubiquitous purine nucleoside, increased by hypoxia, ischemia and tissue damage that mediates a number of physiopathological effects by interacting with four G-protein-coupled receptors, identified as A1 , A2A , A2B , and A3 . Physiological and acutely-increased adenosine is associated with beneficial effects mostly including vasodilation and decrease of inflammation. In contrast chronic overproduction of adenosine occurs in important pathological states, where long lasting increases in the nucleoside levels are responsible for the bad side of adenosine associated with chronic inflammation, fibrosis and organ damage. In this review we describe and critically discuss the pathologic overproduction of adenosine analysing when, where and how adenosine exerts its detrimental effects through the body.

  13. The Clinical Application Value of Dual-source CT's Dual Energy Scanning in the Diagnosis of Liver Tumor%双源CT双能量扫描诊断肝脏肿瘤临床应用价值探讨

    Institute of Scientific and Technical Information of China (English)

    余丁福

    2015-01-01

    Objective The Thesis aims to probe into the Clinical application value of dual-source CT’s dual energy scanning in the diagnosis of liver tumor.Methods We have took a comprehensive researches and analysis on the clinical image data of 50 liver tumor patients under the dual-source CT’s dual energy scan during the period of June 2013 to May 2014 in our hospital.Results With the analysis of different scan ways picked by the patients, and comparison with the value of TNE and VNC CT of the liver spleen aorta abdominalis Muscle behind muscles, it shows the difference between the two is not statistically signiifcant(P>0.05). The value of primary carcinoma of liver related with TNE and VNC CT which is relfected on the substantial iodine density image is lower than that of hepatic hemangioma and cholangiocellular carcinoma, however, the difference is statistically signiifcant.Conclusion Dual energy scanning has the potential Clinical application value in the diagnosis of liver tumor, which should get a big promotion and application.%目的:探讨双源CT双能量扫描在诊断肝脏肿瘤中的临床应用价值。方法选取2013年6月-2014年5月在该院行双源CT双能量扫描的50例肝脏肿瘤患者的临床及影像资料进行分析研究。结果针对患者选择的扫描方式不同,对比患者肝脏、脾脏、腹主动脉、肌柱后方肌肉TNE与VNC CT值,二者间的差异无统计学意义(P>0.05),原发性肝癌在实质期碘基图像上的二者数值分别低于肝血管瘤、胆管细胞癌,差异具有明显统计学意义(P<0.05)。结论双能量扫描在诊断肝脏肿瘤中具有潜在的临床应用价值,应得到推广使用。

  14. 双源CT双能量技术在痛风诊断中的初步应用%Preliminary application of dual source dual energy CT in the diagnosis of gout

    Institute of Scientific and Technical Information of China (English)

    高江晖; 李玉芳; 马洪宇; 郭文伟; 张荣恒; 李攀; 石少聪

    2016-01-01

    Objective To evaluate the effect of dual energy CT in urate crystals in extremities joints of gout. Methods Forty-two cases with gout and 12 cases as control were examinated by dual source CT. The 80 kV,140 kV and 120 kV hybrid energy were collected after one-time scaning. After scanning the image data processed within Syngo. via. Dual-Energy GOUT software,the difference between the gout group and the control group was compared. Results The 42 patients were found with hands and feet multiple urate crystals,finger( toe)between the joints and surrounding soft tissues was more seri-ous;while no gout was found in hands and feet of 12 cases of control group. Conclusions Dual source DECT technology can display the urate crystal,which can be used as routine examination for the gout screening.%目的:探讨双源CT双能量成像技术在痛风患者四肢关节尿酸盐结晶检出中的应用。方法42例痛风性关节炎患者及12例对照组患者行双源 CT双能量扫描,获得80、140 kV双能图像和120 kV混合能量图像,扫描数据在Syngo. via. Dual-Energy GOUT软件内进行图像后处理,比较痛风组与对照组痛风石的差异。结果42例患者均发现双手、双足多发尿酸盐结晶,以指(趾)间关节及周围软组织内为著,12例对照组患者双手、双足均未显示尿酸盐结晶。结论双源 CT双能量技术能明确显示尿酸盐结晶,具有较高的临床应用价值,可作为痛风筛查的常规检查项目。

  15. 泌尿系结石成分的体内双源双能量CT分析%Identification of Urinary Stone Composition with Dual-energy Acquisition of Dual-source CT in Vivo

    Institute of Scientific and Technical Information of China (English)

    凃备武; 周洁; 李惠民; 耿娟

    2013-01-01

    目的:探讨双源CT双能量技术体内分析泌尿系结石成分的可行性和准确性.方法:104例泌尿系结石患者共113结石纳入研究,全部完成双源CT双能量扫描并于工作站(syngo)上完成结石成分分析,全部结石取出后完成红外线光谱分析确定成分.结果:全部病人均顺利完成体内结石成分分析,以红外线光谱分析为参照标准,双源CT双能量分析显示尿酸、草酸钙和磷灰石成分分别得到准确性97.3%、92.9%、38.1%,灵敏度88.2%、100%、9.6%,特异度99.0%、66.7%、90.0%,阳性预测值93.8%、91.7%、63.6%,以及阴性预测值97.9%、100%、35.3%.胱氨酸盐均为假阳性.结论:双源CT双能量技术分析体内泌尿系结石成分是可行的,对尿酸和草酸钙的定性有很高的准确性,具有较高的临床实用价值.%Purpose: To investigate the clinical value of the determination of renal stone composition in vivo with dual-source dual-energy CT. Methods: One hundred and four cases with 113 renal stones were collected. All cases were scanned with dual-energy acquisition by dual-source CT. The data were sent to the workstation for the analysis of the stone composition. The urinary stones were analyzed by infrared spectroscopy after surgery. These two results were compared and the infrared spectroscopy result was taken as the reference standard. Results: The accuracy, sensitivity, specificity, positive and negative predictive value of the dual-energy CT for the diagnosis of uric acid stone were 97.3%, 88.2%, 99.0%, 93.8%, and 97.9% respectively; those of oxalate were 92.9%, 100%, 66.7%, 91.7%, 100%, and those of apatite were 38.1%, 9.6%, 90.0%, 63.6%, 35.3%. All cystine stones were with false positive results. Conclusion: Dual source dual-energy CT has high accuracy for identifying uric acid and oxalate stone in vivo and can be used clinically.

  16. Dual electrospray ionization source for confident generation of accurate mass tags using liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Nepomuceno, Angelito I; Muddiman, David C; Bergen, H Robert; Craighead, James R; Burke, Michael J; Caskey, Patrick E; Allan, Jonathan A

    2003-07-15

    Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) has rapidly established a prominent role in proteomics because of its unparalleled resolving power, sensitivity and ability to achieve high mass measurement accuracy (MMA) simultaneously. However, space-charge effects must be quantitatively, routinely, and confidently corrected because they are known to profoundly influence MMA. We argue that the most effective way to account for space-charge effects is to introduce an internal mass calibrant (IMC) using a dual electrospray ionization (ESI) source where the IMC is added from a separate ESI emitter. The major disadvantage of our initial dual ESI source to achieve high MMA, and arguably the only one, was the time required to switch between the analyte emitter and IMC emitter (i.e., >300 ms). While this "switching time" was acceptable for direct infusion experiments, it did not lend itself to high-throughput applications or when conducting on-line liquid separations. In this report, we completely redesigned the dual ESI source and demonstrate several key attributes. First, the new design allows for facile alignment of ESI emitters, undetectable vibration, and the ability to extend to multiple emitters. Second, the switching time was reduced to IMC to be accumulated "simultaneously" in the external ion reservoir and injected as a single ion packet into the ion cyclotron resonance cell, eliminating the need for a separate accumulation and ion injection event for the IMC. Third, by using a high concentration of the IMC, the residence time on this emitter could be reduced to approximately 80 ms, allowing for more time spent accumulating analyte ions of significantly lower concentration. Fourth, multiplexed on-line separations can be carried out providing increased throughput. Specifically, the new dual ESI source has demonstrated its ability to produce a stable ion current over a 45-min time period at 7 T resulting in mass accuracies of 1.08 ppm +/- 0

  17. Application of dual-source-computed tomography in pediatric cardiology in children within the first year of life; Einsatz der Dual-Source-Computertomografie in der Kinderkardiologie bei Kindern im ersten Lebensjahr

    Energy Technology Data Exchange (ETDEWEB)

    Hausmann, P.; Stenger, A.; Dittrich, S.; Gloeckler, M. [Erlangen-Nuernberg Univ., Erlangen (Germany). Pediatric Cardiology; Cesnjevar, R.; Rueffer, A. [Erlangen-Nuernberg Univ., Erlangen (Germany). Congenital Heart Surgery; Hammon, M.; Uder, M.; Rompel, O. [Erlangen-Nuernberg Univ., Erlangen (Germany). Radiology

    2016-02-15

    To assess fields of application and value of dual source computed tomography (DSCT) for diagnostics and therapy in patients with congenital heart disease during their first year of life. Evaluation of image quality, surgical use and radiation exposure of 2nd and 3rd generation DSCT. DSCT was applied in 118 cases between January 2012 and October 2014 for diagnostics of congenital heart defects. 2nd generation was used in 91 cases until April 2014 and 3rd generation in 27 cases during the period thereafter. 3D reconstructions of the image data were created for clinical diagnostics and planning of interventions. Image quality was assessed using a 4-point-scale. The visibility of the mammary arteries was analyzed, and signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) were calculated. The usefulness of 3D-reconstructions for surgical planning was rated using a 5-point-scale. Radiation exposure and contrast dye consumption were determined. All cases were analyzed retrospectively. DSCT was successfully used in 118 cases. All image data obtained were interpretable. More than 60 percent of cases did not show any artifacts. The mammary arteries were visible down to the diaphragmatic arch in more than 80 percent of cases. Diagnostic value and surgical benefit were evaluated as ''useful'' or as ''essential'' in all cases. Median radiation dose was 0.4 mSv and 0.27 mSv for the 2nd and 3rd generation DSCT, respectively. Consumption of contrast dye was 2 ml/kg in all cases. DSCT is a modern and extremely helpful technique for diagnostics and planning of interventions in patients with complex congenital heart defects. Extracardiac vascular structures in particular can be depicted three-dimensionally at high resolution. The use of iterative reconstruction with 3rd generation DSCT yielded image quality similar to that of 2nd generation DSCT at considerably reduced radiation exposure level compared to 2nd generation DSCT. 3rd

  18. The use of dual source CT in diagnosis of carotid body tumors%双源CT在颈动脉体瘤诊治中的应用

    Institute of Scientific and Technical Information of China (English)

    曹罡; 郭婷; 周长圣; 张森林; 孟昭业; 杨震; 董震; 徐金科; 毛钊

    2011-01-01

    Objective To evaluate the value of dual source CT in diagnosis and treatment of carotid body tumors.Methods Between Sep, 2007 and April 2010, a total of 5 patients who were planed to be diagnosed as carotid body underwent dual source CT.The relationship of the tumour and the near vessels, and the character of the tumor were identified by analysis of clinical signs and imaging results.The risk factors and feasibility of operations were evaluated before done.The tumors were resected.Results The clear edge mass of soft tissue was shown in all 5 patients in dual source CT images at the bifurcation of the common carotid artery.The minors presented obviously enhanced high-density after contrast media administration.The tumors have plenty blood supply.4 patients with small tumor in only one side show especially “cup-sign”.One female patient with bilateral tumors didn't have“ cup-sign” and significant narrow blood vessel, however the tumors were much bigger.5 patients were all diagnosed by dual source CT.The tumonrs were resected and reserved common carotid artery and internal carotid artery.Couclusion Dual source CT is convenience, non-trauma.Its information can be composited.It can offer overall image information of the blood vessel disease such as CBT, which is very important for diagnosis, typing, evaluation the risk of the operation of CBT.So, dual source CT can be the first choice in the diagnosis of carotid body tumor.%目的 评价双源CT(dual source CT,DSCT)在颈动脉体瘤(carotid body tumor,CBT)诊断、治疗中的价值.方法 2007年9月至2010年4月对临床拟诊CBT的5例行颈部双源CT检查,根据临床体征及影像学检查确定肿瘤的性质及其与颈总、颈内、颈外动脉的关系,评估手术的风险及可行性.结果 5例DSCT检查结果均显示颈总动脉分叉处界线清晰的软组织实性肿块.增强扫描后病灶均呈明显强化,瘤体血供丰富.4例单侧瘤体较小CBT呈现典型的"高脚杯"征.1例双

  19. Compact High-Repetition-Rate Monochromatic Terahertz Source Based on Difference Frequency Generation from a Dual-Wavelength Nd:YAG Laser and DAST Crystal

    Science.gov (United States)

    Zhong, Kai; Mei, Jialin; Wang, Maorong; Liu, Pengxiang; Xu, Degang; Wang, Yuye; Shi, Wei; Yao, Jianquan; Teng, Bing; Xiao, Yong

    2017-01-01

    Although high-repetition-rate dual-wavelength Nd:YAG lasers at 1319 and 1338 nm have been realized for quite a long time, we have employed it in generating monochromatic terahertz (THz) wave in this paper for the first time. The dual-wavelength laser was LD-end-pumped and acousto-optically (AO) Q-switched with the output power of watt level operating at different repetition rates from 5.5 to 30 kHz. Using a 0.6-mm-thick organic nonlinear crystal DAST for difference frequency generation (DFG), a compact terahertz source was achieved at 3.28 THz. The maximum average output power was about 0.58 μW obtained at a repetition rate of 5.5 kHz, corresponding to the conversion efficiency of about 6.4 × 10-7. The output power scaling is still feasible with higher pump power and a longer nonlinear DFG crystal. Owing to the compactness of the dual-wavelength laser and the nonlinear crystal, a palm-top terahertz source is expected for portable applications such as imaging and so on.

  20. Structure Parameter Optimization of Air-water Dual-source Compound Heat-exchanger%空气-水双热源复合换热器结构参数优化

    Institute of Scientific and Technical Information of China (English)

    张超; 董家昀; 赵晓丹; 周光辉

    2012-01-01

    空气-水双热源复合换热器是太阳能-空气双热源复合热泵系统的核心部件,空气-水双热源复台换热器的结构参数对空气-水双热源复合换热器的换热性能以及太阳能-空气双热源复合热泵的系统性能具有重要影响.建立了太阳能-空气双热源复合热泵系统的数学模型,利用数学模拟的方法研究了空气-水双热源复合换热器结构参数对热泵系统能效比的影响,并确定了模拟工况下换热器结构参数的优化方案.%The air-water dual-source compound heat-exchanger is the key component of the solar-air dual-source compound heat pump system. The heat-exchanging performance of the air-water dual-source compound heat-exchanger and the system performance of the solar-air dual-source compound heat pump system are largely depended on the structure parameter of the air-water dual-source compound heat-exchanger. The mathematic model of the solar-air dual-source compound heat pump system has been established. The mathematic simulation method has been used to study the effect of the structure parameters of air-water dual-source compound heat-exchanger on the energy-efficiency ratio of the solar-air dual-source compound heat pump system, and the optimization scheme of the structure parameters under the simulating condition have been determined.

  1. Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings

    Energy Technology Data Exchange (ETDEWEB)

    Busch, S.; Johnson, T.R.C.; Wintersperger, B.J.; Minaifar, N.; Bhargava, A.; Rist, C.; Reiser, M.F.; Becker, C.; Nikolaou, K. [University of Munich, Department of Clinical Radiology, Munich (Germany)

    2008-03-15

    Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT), the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study was to evaluate the accuracy of DSCT in the assessment of left ventricular functional parameters with cardiac magnetic resonance imaging (MRI) as standard of reference. Fifteen patients (two female, 13 male; mean age 50.8 {+-} 19.2 years) underwent CT and MRI examinations on a DSCT (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) and a 3.0-Tesla MR scanner (Magnetom Trio; Siemens Medical Solutions), respectively. Multiphase axial CT images were analysed with a semiautomatic region growing algorithms (Syngo Circulation; Siemens Medical Solutions) by two independent blinded observers. In MRI, dynamic cine loops of short axis slices were evaluated with semiautomatic contour detection software (ARGUS; Siemens Medical Solutions) independently by two readers. End-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined for both modalities, and correlation coefficient, systematic error, limits of agreement and inter-observer variability were assessed. In DSCT, EDV and ESV were 135.8 {+-} 41.9 ml and 54.9 {+-} 29.6 ml, respectively, compared with 132.1 {+-} 40.8 ml EDV and 57.6 {+-} 27.3 ml ESV in MRI. Thus, EDV was overestimated by 3.7 ml (limits of agreement -46.1/+53.6), while ESV was underestimated by 2.6 ml (-36.6/+31.4). Mean EF was 61.6 {+-} 12.4% in DSCT and 57.9 {+-} 9.0% in MRI, resulting in an overestimation of EF by 3.8% with limits of agreement at -14.7 and +22.2%. Rank correlation rho values were 0.81 for EDV (P = 0.0024), 0.79 for ESV (P = 0.0031) and 0.64 for EF (P = 0.0168). The kappa value of inter

  2. Congenital coronary artery fistulas: dual-source CT findings from consecutive 6624 patients with suspected or confirmed coronary artery disease

    Institute of Scientific and Technical Information of China (English)

    YUN Hong; ZENG Meng-su; YANG Shan; JIN Hang; YANG Xue

    2011-01-01

    Background Coronary artery fistulas (CAFs) are rare congenital abnormality often unintentionally found in patients with coronary artery disease.Clinical diagnosis of CAFs is difficult due to symptomless or lack of specific symptoms.Dual-source computed tomography (DSCT) might be a useful diagnostic tool for CAFs.The study aimed to retrospectively summarize the imaging features of CAFs delineated at DSCT in 48 CAF patients detected from consecutive 6624 patients with suspected or confirmed coronary artery disease in our institution.Methods Forty-eight patients underwent DSCT angiography by using retrospective electrocardiographic (ECG) gating after infusion of 70 ml of intravenous contrast material during breath hold.Maximum intensity projection (MIP),curved planar reconstruction (CPR),and volume rendering technique (VR) were obtained.Anomalous termination of coronary artery in each subject was evaluated by two radiologists (with more than 10 years experience with cardiovascular imaging),and disagreement between diagnosis readers was settled by a consensus reading.Ten of 48 patients also underwent traditional coronary angiography (CAG) simultaneously.Results In each CAF case,DSCT angiography clearly demonstrated the origin,the termination,the size of abnormal vessel and its course in relation to surrounding great vessels.CAF arising from right coronary artery was the most common type,left circumflex was the least one involved among three coronaries,and pulmonary artery was the most common drainage site.Aneurismal fistulous tract,coronary atherosclerosis,myocardial bridging and anomalous origin of coronary artery were also detected in this group.The demonstration of drainage sites in CAG was consistent with DSCT angiography in 9 patients,and judgment on one anomalous connection in CAG was inconsistent with that in DSCT angiography.Conclusions DSCT angiography could provide accurate delineation of anomalous communications,size and numbers of fistulas in patients with

  3. Adenosine, Energy Metabolism, and Sleep

    Directory of Open Access Journals (Sweden)

    Tarja Porkka-Heiskanen

    2003-01-01

    Full Text Available While the exact function of sleep remains unknown, it is evident that sleep was developed early in phylogenesis and represents an ancient and vital strategy for survival. Several pieces of evidence suggest that the function of sleep is associated with energy metabolism, saving of energy, and replenishment of energy stores. Prolonged wakefulness induces signs of energy depletion in the brain, while experimentally induced, local energy depletion induces increase in sleep, similarly as would a period of prolonged wakefulness. The key molecule in the induction of sleep appears to be adenosine, which induces sleep locally in the basal forebrain.

  4. Aberrant bone density in aging mice lacking the adenosine transporter ENT1.

    Directory of Open Access Journals (Sweden)

    David J Hinton

    Full Text Available Adenosine is known to regulate bone production and resorption in humans and mice. Type 1 equilibrative nucleoside transporter (ENT1 is responsible for the majority of adenosine transport across the plasma membrane and is ubiquitously expressed in both humans and mice. However, the contribution of ENT1-mediated adenosine levels has not been studied in bone remodeling. With the recent identification of the importance of adenosine signaling in bone homeostasis, it is essential to understand the role of ENT1 to develop novel therapeutic compounds for bone disorders. Here we examined the effect of ENT1 deletion on bone density using X-ray, dual energy X-ray absorptiometry and micro-computerized tomography analysis. Our results show that bone density and bone mineral density is reduced in the lower thoracic and lumbar spine as well as the femur of old ENT1 null mice (>7 months compared to wild-type littermates. Furthermore, we found increased mRNA expression of tartrate-resistant acid phosphatase (TRAP, an osteoclast marker, in isolated long bones from 10 month old ENT1 null mice compared to wild-type mice. In addition, aged ENT1 null mice displayed severe deficit in motor coordination and locomotor activity, which might be attributed to dysregulated bone density. Overall, our study suggests that ENT1-regulated adenosine signaling plays an essential role in lumbar spine and femur bone density.

  5. Third-generation dual-source 70-kVp chest CT angiography with advanced iterative reconstruction in young children: image quality and radiation dose reduction

    Energy Technology Data Exchange (ETDEWEB)

    Rompel, Oliver; Janka, Rolf; Lell, Michael M.; Uder, Michael; Hammon, Matthias [University Hospital Erlangen, Department of Radiology, Erlangen (Germany); Gloeckler, Martin; Dittrich, Sven [University Hospital Erlangen, Department of Pediatric Cardiology, Erlangen (Germany); Cesnjevar, Robert [University Hospital Erlangen, Department of Pediatric Cardiac Surgery, Erlangen (Germany)

    2016-04-15

    Many technical updates have been made in multi-detector CT. To evaluate image quality and radiation dose of high-pitch second- and third-generation dual-source chest CT angiography and to assess the effects of different levels of advanced modeled iterative reconstruction (ADMIRE) in newborns and children. Chest CT angiography (70 kVp) was performed in 42 children (age 158 ± 267 days, range 1-1,194 days). We evaluated subjective and objective image quality, and radiation dose with filtered back projection (FBP) and different strength levels of ADMIRE. For comparison were 42 matched controls examined with a second-generation 128-slice dual-source CT-scanner (80 kVp). ADMIRE demonstrated improved objective and subjective image quality (P <.01). Mean signal/noise, contrast/noise and subjective image quality were 11.9, 10.0 and 1.9, respectively, for the 80 kVp mode and 11.2, 10.0 and 1.9 for the 70 kVp mode. With ADMIRE, the corresponding values for the 70 kVp mode were 13.7, 12.1 and 1.4 at strength level 2 and 17.6, 15.6 and 1.2 at strength level 4. Mean CTDI{sub vol}, DLP and effective dose were significantly lower with the 70-kVp mode (0.31 mGy, 5.33 mGy*cm, 0.36 mSv) compared to the 80-kVp mode (0.46 mGy, 9.17 mGy*cm, 0.62 mSv; P <.01). The third-generation dual-source CT at 70 kVp provided good objective and subjective image quality at lower radiation exposure. ADMIRE improved objective and subjective image quality. (orig.)

  6. Chandra Observations of a 1.9 kpc Separation Double X-ray Source in a Candidate Dual AGN Galaxy at z=0.16

    CERN Document Server

    Comerford, Julia M; Gerke, Brian F; Madejski, Greg M

    2011-01-01

    We report Chandra observations of a double X-ray source in the z=0.1569 galaxy SDSS J171544.05+600835.7. The galaxy was initially identified as a dual AGN candidate based on the double-peaked [O III] emission lines, with a line-of-sight velocity separation of 350 km/s, in its Sloan Digital Sky Survey spectrum. We used the Kast Spectrograph at Lick Observatory to obtain two longslit spectra of the galaxy at two different position angles, which reveal that the two AGN emission components have not only a velocity offset, but also a projected spatial offset of 1.9 kpc/h70 on the sky. Chandra/ACIS observations of two X-ray sources with the same spatial offset and orientation as the optical emission suggest the galaxy most likely contains Compton-thick dual AGN, although the observations could also be explained by AGN jets. Deeper X-ray observations that reveal Fe K lines, if present, would distinguish between the two scenarios. The observations of a double X-ray source in SDSS J171544.05+600835.7 are a proof of co...

  7. CT diagnosis of dual source for pulmonary embolism%肺动脉栓塞的炫速双源CT诊断

    Institute of Scientific and Technical Information of China (English)

    邢漠

    2015-01-01

    Objective: To investigae and analyze the CT diagnostic performance of dual source for pulmonary embolism.Methods: he records of 35 cases with pulmonary embolism from August 2012 to April 2015 were retrospectively analyzed by prior implementation of Hyun-speed dual-source CT scan followed by the elbow injection omnipaque or ultravist,the implementation of the second scan was delayed by 30 s.Finally,the results of diagnosis were observed and analyzed.Results: Hyun-speed dual-source CT scan examination diagnosed: 18 patients with markings sparse,16 patients of pulmonary infarction form,5 patients with pulmonary hypertension,11 patients with pleural effusion and 6 patients with pleural thickening.After enhanced scan,the majority of patients with arterial filling defect tiny face.Conclusion: Hyun-speed dual-source CT scanning for diagnosis of pulmonary embolism has advantage of being fast with good image clarity providing timely scan with safety and clear scannings.It can depict variety of small lesions.%目的:探讨分析肺动脉栓塞的炫速双源CT诊断效果.方法:采取回顾性分析法,抽取2012年8月—2015年4月经临床确诊的35例肺动脉栓塞患者,事先实施炫速双源CT平扫,而后经肘注射欧乃派克或者优维显,延迟30 s后实施第2次扫描,观察分析检查诊断结果.结果:经炫速双源CT平扫检查,有18例患者肺纹理稀疏,16例患者肺梗死灶形成,5例患者肺动脉高压,11例患者胸腔积液,6例患者胸膜肥厚.经增强扫描检查后,大部分患者充盈缺损与动脉面细小.结论:采用炫速双源CT扫描诊断肺动脉栓塞,速度快且图像清晰,可及时扫描并观察各种小病灶,安全有效.

  8. Assessment of global left ventricular function with dual-source computed tomography in patients with valvular heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Bak, So Hyeon; Jeon, Hae Jeong (Dept. of Radiology, Konkuk Univ. Hospital, Konkuk Univ. School of Medicine, Seoul (Korea, Republic of)); Ko, Sung Min (Dept. of Radiology, Konkuk Univ. Hospital, Konkuk Univ. School of Medicine, Seoul (Korea, Republic of); Research Inst. of Medical Science, Konkuk Univ. Hospital, Konkuk Univ. School of Medicine, Seoul (Korea, Republic of)), Email: 20070437@kuh.ac.kr; Yang, Hyun Suk; Hwang, Hweung Kon (Dept. of Cardiology, Konkuk Univ. Hospital, Konkuk Univ. School of Medicine, Seoul (Korea, Republic of)); Song, Meong Gun (Dept. of Thoracic Surgery, Konkuk Univ. Hospital, Konkuk Univ. School of Medicine, Seoul (Korea, Republic of))

    2012-04-15

    Background: Left ventricular (LV) function is a vital parameter for prognosis, therapy guidance, and follow-up of cardiovascular disease. Dual-source computed tomography (DSCT) provides an accurate analysis of global LV function. Purpose: To assess the performance of DSCT in the determination of global LV functional parameters in comparison with cardiovascular magnetic resonance (CMR) and two-dimensional transthoracic echocardiography (2D-TTE) in patients with valvular heart disease (VHD). Material and Methods: A total of 111 patients (58 men, mean age 49.9 years) with known VHD and who underwent DSCT, 2D-TTE, and CMR a period of 2 weeks before undergoing valve surgery were included in this study. LV end-systolic volume (ESV), end-diastolic volume (EDV), stroke volume (SV), and ejection fraction (EF) were calculated by DSCT using the threshold-based technique, by 2D-TTE using a modified Simpson's method, and by CMR using Simpson's method. Agreement for parameters of LV global function was determined with the Pearson's correlation coefficient (r) and Bland-Altman analysis. All the DSCT and CMR data-sets were assessed independently by two readers. Results: Fifty of the total 111 patients had aortic VHD, 29 patients had mitral VHD, and 32 patients had mixed aortic and mitral VHD. An excellent inter-observer agreement was seen for the assessment of global LV function using DSCT (r 0.910-0.983) and CMR (r = 0.854-0.965). An excellent or good correlation (r 0.93, 0.95, 0.87, and 0.71, respectively, P < 0.001) was noted between the DSCT and 2D-TTE values for EDV, ESV, SV, and EF. EDV (33.7 mL, P < 0.001), ESV (12.1 mL, P < 0.001), SV (21.2 mL, P < 0.001), and EF (1.6%, P = 0.019) were significantly overestimated by DSCT when compared with 2D-TTE. An excellent correlation (r = 0.96, 0.97, 0.91, and 0.94, respectively, P < 0.001) between DSCT and CMR was seen in the evaluation of EDV, ESV, SV, and EF. EDV (15.9 mL, P < 0.001), ESV (7.3 mL, P < 0.001), and SV

  9. Homeostatic control of synaptic activity by endogenous adenosine is mediated by adenosine kinase.

    Science.gov (United States)

    Diógenes, Maria José; Neves-Tomé, Raquel; Fucile, Sergio; Martinello, Katiuscia; Scianni, Maria; Theofilas, Panos; Lopatár, Jan; Ribeiro, Joaquim A; Maggi, Laura; Frenguelli, Bruno G; Limatola, Cristina; Boison, Detlev; Sebastião, Ana M

    2014-01-01

    Extracellular adenosine, a key regulator of neuronal excitability, is metabolized by astrocyte-based enzyme adenosine kinase (ADK). We hypothesized that ADK might be an upstream regulator of adenosine-based homeostatic brain functions by simultaneously affecting several downstream pathways. We therefore studied the relationship between ADK expression, levels of extracellular adenosine, synaptic transmission, intrinsic excitability, and brain-derived neurotrophic factor (BDNF)-dependent synaptic actions in transgenic mice underexpressing or overexpressing ADK. We demonstrate that ADK: 1) Critically influences the basal tone of adenosine, evaluated by microelectrode adenosine biosensors, and its release following stimulation; 2) determines the degree of tonic adenosine-dependent synaptic inhibition, which correlates with differential plasticity at hippocampal synapses with low release probability; 3) modulates the age-dependent effects of BDNF on hippocampal synaptic transmission, an action dependent upon co-activation of adenosine A2A receptors; and 4) influences GABAA receptor-mediated currents in CA3 pyramidal neurons. We conclude that ADK provides important upstream regulation of adenosine-based homeostatic function of the brain and that this mechanism is necessary and permissive to synaptic actions of adenosine acting on multiple pathways. These mechanistic studies support previous therapeutic studies and implicate ADK as a promising therapeutic target for upstream control of multiple neuronal signaling pathways crucial for a variety of neurological disorders.

  10. 双源 CT 双能量技术在泌尿系结石诊断中的应用价值%Application value of dual energy technique of dual source CT in the diagnosis of urinary calculi

    Institute of Scientific and Technical Information of China (English)

    高江晖; 马洪宇; 郭文伟; 于庆康

    2016-01-01

    目的:探讨双源 CT 双能量技术在尿路结石组成分析中的预测价值。方法对30例泌尿系统结石患者行双源 CT 双能量扫描,对结石组成成份进行分析,将结果与红外光谱法分析的结石组成相比,计算双源 CT 分析尿酸盐结石、非尿酸盐结石的特异度与灵敏度,判断预测结石的准确性。结果30例泌尿系结石中尿酸盐类结石10例,非尿酸盐类结石20例,尿酸盐结石、非尿酸盐结石在140 kV 能量下 CT 值分别为(312.5±55.5)HU、(650.6±255.5)HU,在100 kV 能量下 CT 值分别为(328.5±50.5)HU、(960.8±180.5)HU,尿酸盐结石、非尿酸盐结石在两种能量下的差值分别为(16.5±5.1)HU、(310.2±26.7)HU,比值分别为(1.05±0.01)HU、(1.47±0.02) HU,尿酸盐结石差值、比值明显低于非尿酸盐结石(P <0.05),双源 CT 可切确辨别尿酸盐类结石与非尿酸盐类结石,其灵敏度、特异度分别为90%、95%。结论双源 CT 双能量成像技术能在尿路结石治疗前对其组成进行分析,对认识结石的成因及预防结石形成有很大帮助。%Objective To investigate the clinical value of dual source dual energy CT( DS-DECT)in predict chemical component of urinary calculi. Methods Selected 30 cases with urinary cal-culi underwent dual source Flash CT,analysed the component of the calculi,compared the results and in-frared spectroscopy analysis of calculi composition,calculated the specificity and sensitivity of urate cal-culi,non urate calculus by dual source CT analysis,and judged the forecasting accuracy of the calculi. Results Among the 30 urinary calculi patients,10 cases had uric acid calculi and 20 cases had non-u-ric acid calculi. Uric acid calculi and non-uric acid calculi under 140 kV energy:CT values were (312. 5 ± 55. 5)HU,(650. 6 ± 255. 5)HU;under 100 kV energy:CT values were(328. 5 ± 50. 5) HU,(960. 8 ± 180. 5)HU;the difference of acid

  11. Repeated administration of adenosine increases its cardiovascular effects in rats.

    Science.gov (United States)

    Vidrio, H; García-Márquez, F; Magos, G A

    1987-01-20

    Hypotensive and negative chronotropic responses to adenosine in anesthetized rats increased after previous administration of the nucleoside. Bradycardia after adenosine in the isolated perfused rat heart was also potentiated after repeated administration at short intervals. This self-potentiation could be due to extracellular accumulation of adenosine and persistent stimulation of receptors caused by saturation or inhibition of cellular uptake of adenosine.

  12. Dual-source cardiac computed tomography angiography (CCTA) in the follow-up of cardiac transplant: comparison of image quality and radiation dose using three different imaging protocols

    Energy Technology Data Exchange (ETDEWEB)

    Beitzke, D.; Berger-Kulemann, V.; Unterhumer, S.; Loewe, C.; Wolf, F. [Medical University Vienna, Department of Biomedical Imaging and Image Guided Therapy, Division of Cardiovascular and Interventional Radiology, Vienna (Austria); Schoepf, V. [Medical University Vienna, Department of Biomedical Imaging and Image Guided Therapy, Division of Neuroradiology and Musculoskeletal Radiology, Vienna (Austria); Spitzer, E. [Bern University Hospital, Department of Cardiology, Bern (Switzerland); Feuchtner, G.M. [Innsbruck Medical University, Department of Radiology II, Innsbruck (Austria); Gyoengyoesi, M. [Medical University Vienna, Department of Cardiology, Vienna (Austria); Uyanik-Uenal, K.; Zuckermann, A. [Medical University Vienna, Department of Cardiac Surgery, Vienna (Austria)

    2015-08-15

    To prospectively evaluate image quality (IQ) and radiation dose of dual-source cardiac computed tomography (CCTA) using different imaging protocols. CCTA was performed in 150 patients using the retrospective ECG-gated spiral technique (rECG) the prospective ECG-gated technique (pECG), or the prospective ECG-gated technique with systolic imaging and automated tube voltage selection (pECGsys). IQ was rated using a 16-segment coronary artery model. Techniques were compared for overall IQ, IQ of the large and the small coronary artery segments. Effective dose was used for comparison of radiation dose. Overall IQ and IQ of the large segments showed no differences between the groups. IQ analysis of the small segments showed lowered IQ in pECGsys compared to rECG (p = 0.02), but not to pECG (p = 0.6). Effective dose did not differ significantly between rECG and pECG (p = 0.13), but was significantly lower for pECGsys (p < 0.001 vs. rECG and pECG). Radiation dose of dual-source CCTA in heart transplant recipients is significantly reduced by using prospective systolic scanning and automated tube voltage selection, while overall IQ and IQ of the large coronary segments are maintained. IQ appears to be lower compared to retrospective techniques with regard to small coronary segments. (orig.)

  13. Contrast volume reduction using third generation dual source computed tomography for the evaluation of patients prior to transcatheter aortic valve implantation

    Energy Technology Data Exchange (ETDEWEB)

    Bittner, Daniel O. [University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Department of Internal Medicine 2 (Cardiology), Erlangen (Germany); Harvard Medical School, Cardiac MR PET CT Program, Massachusetts General Hospital, Boston, MA (United States); Arnold, Martin; Klinghammer, Lutz; Schuhbaeck, Annika; Hell, Michaela M.; Muschiol, Gerd; Gauss, Soeren; Achenbach, Stephan; Marwan, Mohamed [University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Department of Internal Medicine 2 (Cardiology), Erlangen (Germany); Lell, Michael; Uder, Michael [University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Department of Radiology, Erlangen (Germany); Hoffmann, Udo [Harvard Medical School, Cardiac MR PET CT Program, Massachusetts General Hospital, Boston, MA (United States)

    2016-12-15

    Chronic renal failure is common in patients referred for transcatheter aortic valve implantation (TAVI). CT angiography is recommended and provides crucial information prior to TAVI. We evaluated the feasibility of a reduced contrast volume protocol for pre-procedural CT imaging. Forty consecutive patients were examined with prospectively ECG-triggered high-pitch spiral acquisition using a novel third-generation dual-source CT system; 38 ml contrast agent was used. Image quality was graded on a visual scale (1-4). Contrast attenuation was measured at the level of the aortic root and at the iliac bifurcation. Mean patient age was 82 ± 6 years (23 males; 58 %). Mean attenuation/average image quality was 285 ± 60 HU/1.5 at the aortic annulus compared to 289 ± 74 HU/1.8 at the iliac bifurcation (p = 0.77/p = 0.29). Mean estimated effective radiation dose was 2.9 ± 0.3 mSv. A repeat acquisition was necessary in one patient due to image quality. Out of the 35 patients who underwent TAVI, 31 (89 %) patients had no or mild aortic regurgitation. Thirty-two (91 %) patients were discharged successfully. Pre-procedural CTA with a total of 38 ml contrast volume is feasible and clinically useful, using third-generation dual-source CT, allowing comprehensive imaging for procedural success. (orig.)

  14. The Value Study In Urinary Stone Composition Analysis by Dual Source CT Dual Energy Technology%双源CT双能量技术在尿路结石成分分析中的应用价值研究

    Institute of Scientific and Technical Information of China (English)

    刘志鹏; 沈剑辉; 汤连志; 姜洪

    2016-01-01

    Objective The purpose of this paper is to explore the application value of dual energy CT technology in the determination of urinary stone composition. Methods A total of 86 patients with acute abdominal pain in our hospital from September 2014 to November 2015 were selected. For patients with implementation of dual source CT examination and by scanning results analysis of stone composition, and with the stones after operation in vitro infrared spectrum analysis results, make analysis of dual source CT diagnostic value. Results DUALSOURCE CT were found in 136 pa-tients with stones in 70 cases, 57 cases of infrared spectroscopy confirmed that 98. Among them, calcium oxalate stones 86, accounting for all 87.76%(86/98);uric acid stones in 5 cases, 7, accounting for 7.14%(7/98);other stones in 4 cas-es, 5, accounting for 5.10%(5/98). Conclusion Dual source CT in urinary system stones with good accuracy, and can effectively accurately distinguish stones of different components of the composition, make accurate judgment, provide accurate reference for clinicians to the next treatment in the analysis.%目的:该文旨在探究双源CT双能量技术在尿路结石成分分析中的应用价值。方法选取2014年9月—2015年11月间于该院检查的疑似泌尿系统结石的腹部锐痛患者共86例。对患者实施双源CT检查,由扫描结果分析结石成分,并同结石术后体外红外光谱分析结果相对照,作出双源CT诊断价值分析。结果双源CT检查后共发现70例患者的136颗结石,红外光谱证实57例,98颗。其中草酸钙结石86颗,占全部的87.76%(86/98);尿酸结石5例,7颗,占全部的7.14%(7/98);其它结石4例,5颗,占全部的5.10%(5/98)。结论双源CT在分析泌尿系统结石中的准确性较好,可有效地准确区分组成成分不同的结石,作出准确的判定,为临床医生接下来的诊疗提供准确地参考依据。

  15. Accuracy of dual-source CT to identify significant coronary artery disease in patients with uncontrolled hypertension presenting with chest pain: comparison with coronary angiography.

    Science.gov (United States)

    Marwan, Mohamed; Pflederer, Tobias; Schepis, Tiziano; Seltmann, Martin; Klinghammer, Lutz; Muschiol, Gerd; Ropers, Dieter; Daniel, Werner G; Achenbach, Stephan

    2012-06-01

    It has been previously reported that the sensitivity and specificity of multislice CT for detecting significant CAD (coronary artery disease) is high. Chest pain is a common presentation in patients with uncontrolled hypertension. We investigated the sensitivity and specificity of dual-source CT to detect and rule out significant CAD in patients presenting with uncontrolled hypertension accompanied by chest pain. 260 consecutive patients presenting with acute chest pain in the context of stage 2 hypertension (systolic pressure ≥160 and/or diastolic pressure ≥100) were enrolled in the study. After admission, control of blood pressure and risk stratification, 82 patients were excluded due to renal insufficiency, prior coronary revascularisation or refused participation in the study. 90 further patients with low pre-test probability of CAD were also excluded. 88 remaining patients were subjected to CT coronary angiography using dual-source CT (Definition, Siemens Medical Solutions, Forchheim, Germany) within 24 h before invasive coronary angiography. A contrast-enhanced volume dataset was acquired (120 kV, 400 mAs/rot, collimation 2 × 64 × 0.6 mm, retrospective ECG gating). Data sets were evaluated concerning the presence or absence of significant coronary stenoses and validated against invasive coronary angiography. A significant stenosis was assumed if the diameter reduction was ≥50%. 88 patients (mean age 66 ± 11 years, mean heart rate 61 ± 9 bpm) were evaluated regarding the presence or absence of significant CAD (at least one stenosis ≥50% diameter reduction). Mean systolic blood pressure on presentation was 203 ± 20 mmHg and mean diastolic blood pressure was 103 ± 13 mmHg. On a per patient basis, the sensitivity and specificity for dual-source CT to detect significant CAD in vessels >1.5 mm diameter was 100% (36/36, 95% CI 90-100) and 90% (47/52, 95% CI 79-97), respectively with a negative predictive value (NPV) of 100% (47/47, 95% CI 92-100) and a

  16. The influence factors of the compound heat-exchanging temperature difference of dual-source compound heat-exchanger%双热源复合换热器复合换热温差影响因素分析

    Institute of Scientific and Technical Information of China (English)

    张超; 董家昀; 赵晓丹; 周光辉

    2012-01-01

    空气-水双热源复合换热器是太阳能-空气双热源复合热泵系统的核心部件,空气-水双热源复合换热器的有效复合换热温差对空气-水双热源复合换热器的换热性能以及太阳能-空气双热源复合热泵的系统性能具有重要影响.建立了空气-水双热源复合换热器和太阳能-空气双热源复合热泵系统的数学模型,利用数学模拟的方法研究了空气-水双热源复合换热器结构参数,即内外管径、翅片间距对有效复合换热温差的影响.模拟结果表明:空气-水双热源复合换热器的有效复合换热温差随内管管径的减小、外管管径的增大以及翅片间距的减小而增大.%The air - water dual - source compound heat - exchanger is the key component of the solar - air dual - source compound heat pump system. The heat - exchanging performance of the air - water dual - source compound heat - exchanger and the system performance of the solar - air dual - source compound heat pump system largely depend on the effective compound heat - exchanging temperature difference of the air - water dual - source compound heat - exchanger. The mathematic models of the air - water dual - source compound heat - exchanger and the solar ?air dual - source compound heat pump system were established, and the mathematic simulation was used to study the effect of the structure parameters of air - water dual - source compound heat - exchanger such as the tube diameter and the fin space on the effective compound heat - exchanging temperature difference. The simulated results show that the effective compound heat - exchanging temperature difference of the air - water dual - source compound heat - exchanger increases while the inner - tube diameter and the fin space decrease, and the outer - tube diameter increases.

  17. Mast cell adenosine receptors function: a focus on the A3 adenosine receptor and inflammation

    Directory of Open Access Journals (Sweden)

    Noam eRudich

    2012-06-01

    Full Text Available Adenosine is a metabolite, which has long been implicated in a variety of inflammatory processes. Inhaled adenosine provokes bronchoconstriction in asthmatics or chronic obstructive pulmonary disease (COPD patients, but not in non-asthmatics. This hyper responsiveness to adenosine appears to be mediated by mast cell activation. These observations have marked the receptor that mediates the bronchoconstrictor effect of adenosine on mast cells, as an attractive drug candidate. Four subtypes (A1, A2a, A2b and A3 of adenosine receptors have been cloned and shown to display distinct tissue distributions and functions. Animal models have firmly established the ultimate role of the A3 adenosine receptor (A3R in mediating hyper responsiveness to adenosine in mast cells, although the influence of the A2b adenosine receptor was confirmed as well. In contrast, studies of the A3R in humans have been controversial. In this review, we summarize data on the role of different adenosine receptors in mast cell regulation of inflammation and pathology, with a focus on the common and distinct functions of the A3R in rodent and human mast cells. The relevance of mouse studies to the human is discussed.

  18. [Adenosine deaminase in experimental trypanosomiasis: future implications].

    Science.gov (United States)

    Pérez-Aguilar, Mary Carmen; Rondón-Mercado, Rocío

    2015-09-01

    The adenosine deaminase represents a control point in the regulation of extracellular adenosine levels, thus playing a critical role in the modulation of purinergic responses to certain pathophysiological events. Several studies have shown that serum and plasma enzyme levels are elevated in some diseases caused by microorganisms, which may represent a compensatory mechanism due to the elevated levels of adenosine and the release of inflammatory mediators. Recent research indicates that adenosine deaminase activity decreases and affects hematological parameters of infected animals with Trypanosoma evansi, so that such alterations could have implications in the pathogenesis of the disease. In addition, the enzyme has been detected in this parasite; allowing the inference that it could be associated with the vital functions of the same, similar to what occurs in mammals. This knowledge may be useful in the association of chemotherapy with specific inhibitors of the enzyme in future studies.

  19. The Application of Dual source CT and Dual Energy Imaging to the Diagnosis of Pulmonary Embolism%双源CT双能量成像在肺动脉栓塞诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    彭可雨; 阮兵; 梁汉欢; 张洪; 梁艳

    2016-01-01

    Objective To study the value of dual energy pulmonary angiography (DECTPA) with dual-source CT (DSCT) in pulmonary embolism (PE).Methods Collected the clinical data of 26 patients suspected of PE in our hospital underwent DECTPA with DSCT. Assessed the value of dual energy pulmonary angiography (DECTPA) with dual-source CT (DSCT) in pulmonary embolism (PE).Results The 96.30%, 90.57% agreement between DEPI and CTPA were showed in the levels of lung and partial lung respectively. Complete filling defects of segmental and subsegmental pulmonary arteries mostly showed correspon dence perfusion defects in the CT perfusion map. However, when there were partial filling defects, most of them were partial perfusion defects. A few of them were normal in the CT perfusion map. With CTPA as a reference standard,in the level of lung, the results show that compared with DEPI, the sensitivity was 96.30% (52/54), specificity of 100% (76/76).Conclusion There was moderate agreement between the judgement of CTPA and DEPI. The perfusion defects in the DEPI related to the degree and location of the filling defects in the CTP A. The combination of CTPA and DEPI will offer more information for diagnosis of the pulmonary embolism. It is worth promotion in the clinical.%目的:探讨双源CT双能量成像在肺动脉栓塞诊断中的应用价值。方法收集在我院使用双源CT双能量肺动脉成像检查的26例临床资料进行分析,探讨双源CT双能量肺动脉成像(DEPI)在肺动脉栓塞中的应用价值。结果在肺叶基础上,DEPI与CTPA检出血管栓塞的符合率为96.30%;在肺段的基础上,DEPI与CTPA检出血管栓塞的符合率为90.57%。当段、亚段肺动脉栓塞充盈缺损完全时,DEPI表现为肺段或亚段分布灌注缺损,当部分充盈缺损时,DEPI以灌注降低为主,少数表现为无灌注缺损;利用DEPI诊断PE的敏感性96.30%(52/54),特异性100%。结论 DEPI表现与CTPA肺动脉栓塞程度、部位有

  20. Evaluation of dual-source parallel RF excitation for diffusion-weighted whole-body MR imaging with background body signal suppression at 3.0 T

    Energy Technology Data Exchange (ETDEWEB)

    Muertz, Petra, E-mail: petra.muertz@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany); Kaschner, Marius, E-mail: marius.kaschner@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany); Traeber, Frank, E-mail: frank.traeber@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany); Kukuk, Guido M., E-mail: guido.kukuk@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany); Buedenbender, Sarah M., E-mail: sarah_m_buedenbender@yahoo.de [Department of Radiology, University of Bonn (Germany); Skowasch, Dirk, E-mail: dirk.skowasch@ukb.uni-bonn.de [Department of Medicine, University of Bonn (Germany); Gieseke, Juergen, E-mail: juergen.gieseke@philips.com [Philips Healthcare, Best (Netherlands); Department of Radiology, University of Bonn (Germany); Schild, Hans H., E-mail: hans.schild@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany); Willinek, Winfried A., E-mail: winfried.willinek@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany)

    2012-11-15

    Purpose: To evaluate the use of dual-source parallel RF excitation (TX) for diffusion-weighted whole-body MRI with background body signal suppression (DWIBS) at 3.0 T. Materials and methods: Forty consecutive patients were examined on a clinical 3.0-T MRI system using a diffusion-weighted (DW) spin-echo echo-planar imaging sequence with a combination of short TI inversion recovery and slice-selective gradient reversal fat suppression. DWIBS of the neck (n = 5), thorax (n = 8), abdomen (n = 6) and pelvis (n = 21) was performed both with TX (2:56 min) and with standard single-source RF excitation (4:37 min). The quality of DW images and reconstructed inverted maximum intensity projections was visually judged by two readers (blinded to acquisition technique). Signal homogeneity and fat suppression were scored as 'improved', 'equal', 'worse' or 'ambiguous'. Moreover, the apparent diffusion coefficient (ADC) values were measured in muscles, urinary bladder, lymph nodes and lesions. Results: By the use of TX, signal homogeneity was 'improved' in 25/40 and 'equal' in 15/40 cases. Fat suppression was 'improved' in 17/40 and 'equal' in 23/40 cases. These improvements were statistically significant (p < 0.001, Wilcoxon signed-rank test). In five patients, fluid-related dielectric shading was present, which improved remarkably. The ADC values did not significantly differ for the two RF excitation methods (p = 0.630 over all data, pairwise Student's t-test). Conclusion: Dual-source parallel RF excitation improved image quality of DWIBS at 3.0 T with respect to signal homogeneity and fat suppression, reduced scan time by approximately one-third, and did not influence the measured ADC values.

  1. SU-D-207-03: Development of 4D-CBCT Imaging System with Dual Source KV X-Ray Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, M; Ishihara, Y; Matsuo, Y; Ueki, N; Iizuka, Y; Mizowaki, T; Hiraoka, M [Kyoto University Hospital, Kyoto, Kyoto (Japan)

    2015-06-15

    Purpose: The purposes of this work are to develop 4D-CBCT imaging system with orthogonal dual source kV X-ray tubes, and to determine the imaging doses from 4D-CBCT scans. Methods: Dual source kV X-ray tubes were used for the 4D-CBCT imaging. The maximum CBCT field of view was 200 mm in diameter and 150 mm in length, and the imaging parameters were 110 kV, 160 mA and 5 ms. The rotational angle was 105°, the rotational speed of the gantry was 1.5°/s, the gantry rotation time was 70 s, and the image acquisition interval was 0.3°. The observed amplitude of infrared marker motion during respiration was used to sort each image into eight respiratory phase bins. The EGSnrc/BEAMnrc and EGSnrc/DOSXYZnrc packages were used to simulate kV X-ray dose distributions of 4D-CBCT imaging. The kV X-ray dose distributions were calculated for 9 lung cancer patients based on the planning CT images with dose calculation grid size of 2.5 x 2.5 x 2.5 mm. The dose covering a 2-cc volume of skin (D2cc), defined as the inner 5 mm of the skin surface with the exception of bone structure, was assessed. Results: A moving object was well identified on 4D-CBCT images in a phantom study. Given a gantry rotational angle of 105° and the configuration of kV X-ray imaging subsystems, both kV X-ray fields overlapped at a part of skin surface. The D2cc for the 4D-CBCT scans was in the range 73.8–105.4 mGy. Linear correlation coefficient between the 1000 minus averaged SSD during CBCT scanning and D2cc was −0.65 (with a slope of −0.17) for the 4D-CBCT scans. Conclusion: We have developed 4D-CBCT imaging system with dual source kV X-ray tubes. The total imaging dose with 4D-CBCT scans was up to 105.4 mGy.

  2. 双源CT对常见泌尿系结石成分定性诊断的价值%The study on Dual energy of dual source CT analyzing urinary stone constituents

    Institute of Scientific and Technical Information of China (English)

    马智军; 冯强; 于洪; 张万伟; 程传明

    2012-01-01

      目的探讨双源CT常见泌尿系结石成分的定性诊断价值以及与饮食、生活习惯、代谢异常的关系.方法收集临床怀疑泌尿结石的病例1256例,分别行双源CT单能量和双能量扫描,扫描后数据传至工作站,统计CT值差值、比值,对体外结石采用标准结石定性分析化学试剂进行分析;不同成分的CT值差值、比值比较行非参数Kruskal-Wal is检验分析,比较两种能量扫描的辐射剂量.结果单能和双能两种模式的辐射剂量比较不具有统计学意义.磷酸钙、草酸钙、胱氨酸、磷酸铵镁、尿酸在两种能量状态下差值均具有统计学意义(P 0.05).人群中患结石的概率与尿和血液生化等指标建立logistic回归方程,P =e3.409x1+1.27x0-0.068+0.014x3-0.182/1+e3.409x1+1.27x0-0.068+0.014x3-0.182.结论双源CT可用于常见五种结石成分的定性诊断.%  Objective To explore the qualitative diagnosis of dual-source CT on urinary stones and analyze the relation between stones and diet, lifestyle, metabolic disorders and diseases of urinary system. Methods Collection of 995 cases of urinary stones were performed dual-source CT scanning, the data transmitted to the work station, the stone were analyzed by qualitative analysis of chemical reagents. The CT value of the difference, ratio compared by nonparametric test, Kruskal-Wallis to compare the two energy scan radiation dose. Results Single energy and dualenergy comparison of dose was not statistically difference(P >0.05), the same as the CT value of the ratio of calcium. The difference of Calcium phosphate, calcium xalate, cystine, struvte, uric acid are statistically difference(P <0.05). The probability of suffering from stones P =e3.409x1+1.27x0-0.068+0.014x3-0.182/1+e3.409x1+1.27x0-0.068+0.014x3-0.182. Conclusion Dual source CT determine the stone size, location, urinary obstruction and qualitatively analyze of stone composition.

  3. Adenosine modulation of [Ca2+]i in cerebellar granular cells: multiple adenosine receptors involved.

    Science.gov (United States)

    Vacas, Javier; Fernández, Mercedes; Ros, Manuel; Blanco, Pablo

    2003-12-01

    Elimination of adenosine by addition of adenosine deaminase (ADA) to the media leads to alterations in intracellular free calcium concentration ([Ca(2+)](i)) in cerebellar granular cells. Adenosine deaminase brings about increases or decreases in [Ca(2+)](i) depending on the previous activation state of the cell. These effects are dependent on the catalytic activity of adenosine deaminase, since its previous catalytic inactivation with Hg(2+) prevents the above-mentioned changes in intracellular calcium. Extracellular calcium is required for the increase in [Ca(2+)](i) promoted by ADA. This rise is insensitive to thapsigargin, but sensitive to micromolar concentrations of Ni(2+). Toxins specific for L, N and P/Q calcium channels do not overtly reduce this effect. N(6)-Cyclopentyl adenosine (CPA), an A(1) receptor agonist, produces a partial reversion of ADA effects, while CGS21680, A(2A)/A(2B) receptor agonist, slightly enhances them. Expression of A(1), A(2A), A(2B) and A(3) adenosine receptor mRNAs was detected in cerebellar granular cell cultures. These results suggest that adenosine modulate [Ca(2+)](i) in cerebellar granule cells through different adenosine receptor subtypes which, at least in part, seem to act through R-type calcium channels.

  4. Study of new dual-source dual-energy CT pulmonary angiography for pulmonary embolism diagnosis%第二代双源CT双能量成像对肺栓塞的诊断价值研究

    Institute of Scientific and Technical Information of China (English)

    吴山; 武志峰; 鄂林宁; 江小鹏

    2012-01-01

    目的:探讨西门子第二代双源CT(Somatom Definition Flash)双能量成像对肺动脉栓塞的诊断价值.方法:回顾性研究42位临床疑诊肺栓塞行双能量肺血管成像(DE-CTPA)扫描的患者的资料,利用工作站双能量软件Lung PBV(肺灌注)、Lung Vessels(肺血管)进行彩色编码成像.2名胸部影像医师结合DE-CTPA与软件提供的信息做出诊断.结果:根据临床及CT结果,其中32例(76.2%,32/42)存在肺动脉栓塞,28例在CTPA上表现为肺动脉充盈缺损,4例在CTPA上未见异常征象,而双能量成像上表现为亚段或以下水平灌注或充盈缺损.双能量Lung PBV测得32例48个栓塞肺区CT强化值(35.6±12.1)HU,低于非栓塞区域所测得的CT强化值(44.5±10.6) HU,t=-2.336,P=0.027.结论:双能量Lung PBV与Lung Vessels软件能显示肺栓塞所致的灌注及充盈缺损,结合CTPA能提高肺栓塞的检出率,特别是外周性肺动脉栓塞.%Objective: To investigate the diagnostic value of the second-generation Siemens dual-source CT(Somatom Definition Flash) dual-energy imaging of pulmonary embolism. Methods: Dual-energy pulmonary angiography (CTPA) data of 42 patients with clinically suspected pulmonary embolism were retrospectively studied by dual—energy software on the workstation. Lung PBV (lung perfusion), Lung Vessels (pulmonary vasculature) and color-coded imaging were analyzed. Two chest-imaging physicians combined information provided by both the DE-CTPA and software to make a diagnosis. Results: According to clinical and CT findings, 32 cases(76.2%, 32/42) had pulmonary embolism, with pulmonary filling defects on CTPA in 28 cases, normal CTPA but perfusion defects in sub-segments or below on DE-CTPA in four cases. Lung PBV measured 32 cases with 48 embolism pulmonary, with a CT enhancement value of (35.6+12.1) HU, lower than the non-embolism region with a CT enhancement value of (44.5±10.6) HU(t=-2.336, P=0.027). Conclusion: Dual-energy lung perfusion(Lung PBV

  5. Dual-source dual-energy CT for the differentiation of urinary stone composition: preliminary study%双源CT双能量成像对泌尿系统结石成分分析的初步研究

    Institute of Scientific and Technical Information of China (English)

    杨琪放; 严景民; 张挽时; 孟利民; 时惠平; 王东; 毕永民; 李相生; 方红; 郭和清

    2011-01-01

    氨酸结石、混合尿酸结石与其他类型结石.%Objective To evaluate dual-source dual-energy CT(DSCT) for the differentiation of urinary stone composition in vitro. Methods Ninety-seven urinary stones were obtained by endoscopic lithotripsy and scanned using dual-source dual-energy CT. The stones were divided into six groups according to infrared spectroscopy stone analysis: uric acid ( UA ) stones ( n = 10 ), cystine stones ( n = 5 ), struvite stones( n = 6), calcium oxalate ( CaOx ) stones ( n = 22 ), mixed UA stones ( n=7 ) and mixed calcium stones(n=47). Hounsfield units (HU) of each stone were recorded for the 80 kV and the 140 kV datasets by hand-drawing method. HU difference, HU ratio and dual energy index ( DEI ) were calculated and compared among the stone groups with one-way ANOVA. Using dual energy software to determine the composition of all stones, results were compared to infrared spectroscopy analysis. Results There were statistical differences in HU difference [(-17±13), (229±34),(309 ±45), (512 ±97), (201±64)and (530±71) HU respectively], in HU ratio (0.96±0.03, 1.34 ±0.04, 1.41 ±0.03, 1.47 ±0.03,1.30±0.07, and 1.49 ±0.03 respectively), and DEI( -0.006 ±0.004, 0.064 ±0.007, 0.080 ±0. 007, 0. 108±0.011 ,0. 055 ±0.014 and 0. 112 ±0.008 respectively ) among different stone groups(F=124. 894,407.028, 322. 864 respectively, P <0. 01 ). There were statistical differences in HU difference,HU ratio and DE1 between UA stones and the other groups( P < 0. 01 ). There were statistical differences in HU difference, HU ratio and DEI between CaOx or mixed calcium stones and the other four groups (P<0. 01 ). There was statistical difference in HU ratio between cystine and struvite stones ( P < 0. 01 ). There were statistical differences in HU difference, HU ratio and DEI between struvite and mixed UA stones (P<0. 05 ). Dual energy software correctly characterized 10 UA stones, 4 cystine stones, 22 CaOx stones and 6 mixed UA

  6. Adenosine stress protocols for myocardial perfusion imaging

    Directory of Open Access Journals (Sweden)

    Baškot Branislav

    2008-01-01

    Full Text Available Background/Aim. Treadmill test combined with myocardial perfusion scintigraphy (MPS is a commonly used technique in the assessment of coronary artery disease. There are many patients, however, who may not be able to undergo treadmill test. Such patients would benefit from pharmacological stress procedures combined with MPS. The most commonly used pharmacological agents for cardiac stress are coronary vasodilatators (adenosine, dipyridamol and catecholamines. Concomitant low-level treadmill exercise with adenosine pharmacologic stress (AdenoEX during MPS has become commonly used in recent years. A number of studies have demonstrated a beneficial impact of AdenoEX protocol. The aim of the study was, besides introducing into practice the two types of protocols of pharmatological stress test with adenosine, as a preparation for MPS, to compare and monitor the frequency of their side effects to quality, acquisition, as well as to standardize the onset time of acquisition (diagnostic imaging for both protocols. Methods. A total of 130 patients underwent pharmacological stress test with adenosine (vasodilatator. In 108 of the patients we performed concomitant exercise (AdenoEX of low level (50W by a bicycle ergometar. In 28 of the patients we performed Adenosine abbreviated protocol (AdenoSCAN. Side effects of adenosine were followed and compared between the two kinds of protocols AdenoEX and AdenoSCAN. Also compared were image quality and suggested time of acquisition after the stress test. Results. Numerous side effects were found, but being short-lived they did not require any active interventions. The benefit of AdenoEX versus AdenoSCAN included decreased side effects (62% vs 87%, improved safety and patients tolerance, improved target-to-background ratios because of less subdiaphragmatic activity, earlier acquisition, and improved sensitivity. Conclusion. The safety and efficacy of adenosine pharmacological stress is even better with concomitant

  7. Dual-frequency comb generation with differing GHz repetition rates by parallel Fabry-Perot cavity filtering of a single broadband frequency comb source

    Science.gov (United States)

    Mildner, Jutta; Meiners-Hagen, Karl; Pollinger, Florian

    2016-07-01

    We present a dual-comb-generator based on a coupled Fabry-Perot filtering cavity doublet and a single seed laser source. By filtering a commercial erbium-doped fiber-based optical frequency comb with CEO-stabilisation and 250 MHz repetition rate, two broadband coherent combs of different repetition rates in the GHz range are generated. The filtering doublet consists of two Fabry-Perot cavities with a tunable spacing and Pound-Drever-Hall stabilisation scheme. As a prerequisite for the development of such a filtering unit, we present a method to determine the actual free spectral range and transmission bandwidth of a Fabry-Perot cavity in situ. The transmitted beat signal of two diode lasers is measured as a function of their tunable frequency difference. Finally, the filtering performance and resulting beat signals of the heterodyned combs are discussed as well as the optimisation measures of the whole system.

  8. High-pitch coronary CT angiography in dual-source CT during free breathing vs. breath holding in patients with low heart rates

    Energy Technology Data Exchange (ETDEWEB)

    Bischoff, Bernhard, E-mail: bernhard.bischoff@med.uni-muenchen.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich (Germany); DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich (Germany); Meinel, Felix G. [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich (Germany); DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich (Germany); Del Prete, Alessandra [Department of Radiology Magrassi-Lanzara, Second University of Naples, Naples (Italy); Reiser, Maximilian F.; Becker, Hans-Christoph [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich (Germany); DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich (Germany)

    2013-12-01

    Background: Coronary CT angiography (CCTA) is usually performed during breath holding to reduce motion artifacts caused by respiration. However, some patients are not able to follow the breathing commands adequately due to deafness, hearing impairment, agitation or pulmonary diseases. The aim of this study was to evaluate the potential of high-pitch CCTA in free breathing patients when compared to breath holding patients. Methods: In this study we evaluated 40 patients (20 free breathing and 20 breath holding patients) with a heart rate of 60 bpm or below referred for CCTA who were examined on a 2nd generation dual-source CT system. Image quality of each coronary artery segment was rated using a 4-point grading scale (1: non diagnostic–4: excellent). Results: Mean heart rate during image acquisition was 52 ±5 bpm in both groups. There was no significant difference in mean image quality, slightly favoring image acquisition during breath holding (mean image quality score 3.76 ± 0.32 in breath holding patients vs. 3.61 ± 0.45 in free breathing patients; p = 0.411). Due to a smaller amount of injected contrast medium, there was a trend for signal intensity to be slightly lower in free breathing patients, but this was not statistically significant (435 ± 123 HU vs. 473 ± 117 HU; p = 0.648). Conclusion: In patients with a low heart rate who are not able to hold their breath adequately, CCTA can also be acquired during free breathing without substantial loss of image quality when using a high pitch scan mode in 2nd generation dual-source CT.

  9. Low dose prospective ECG-gated delayed enhanced dual-source computed tomography in reperfused acute myocardial infarction comparison with cardiac magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Wang Rui, E-mail: rui_wang1979@yahoo.cn [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Zhang Zhaoqi, E-mail: zhaoqi5000@vip.sohu.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Xu Lei, E-mail: leixu2001@hotmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Ma Qin, E-mail: tel1367@gmail.com [Department of Emergency, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); He Yi, E-mail: heyi139@sina.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Lu Dongxu, E-mail: larry.hi@163.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Yu Wei, E-mail: yuwei02@gmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Fan Zhanming, E-mail: fanzm120@tom.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China)

    2011-11-15

    Purpose: To determine whether prospective electrocardiogram (ECG)-gated delayed contrast-enhanced dual-source computed tomography (DCE-DSCT) can accurately delineate the extension of myocardial infarction (MI) compared with delayed enhanced cardiac MR (DE-MR). Material and methods: Eleven patients were examined using dual-source CT and cardiac MR in 2 weeks after a first reperfused MI. DCE-DSCT scan protocol was performed with prospective ECG-gating sequential scan model 7 min after contrast administration. In a 17-model, infarcted myocardium detected by DE-MR was categorized as transmural and subendocardial extension. Segment of infarcted location and graded transmurality were compared between DCE-MDCT and DE-MR. Results: In all eleven patients, diagnostic quality was obtained for depicting delayed enhanced myocardium. Agreement between DCE-DSCT and MR was good on myocardial segment based comparison (kappa = 0.85, p < 0.001), and on transmural and subendocardial infarction type comparison (kappa = 0.82, p < 0.001, kappa = 0.52, p < 0.001, respectively). CT value was higher on infarcted region than that of normal region (100.02 {+-} 9.57 HU vs. 72.63 {+-} 7.32 HU, p < 0.001). Radiation dose of prospectively ECG-gating protocol were 0.99 {+-} 0.08 mSv (0.82-1.19 mSv). Conclusions: Prospective ECG-gated DCE-DSCT can accurately assess the extension and the patterns of myocardial infarction with low radiation dose.

  10. Application of dual-source CT in diagnosis of common atrioventricular canal%双源CT在共同房室通道诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    冯越; 刘铁; 翟利浩

    2012-01-01

    目的 探讨双源CT(DSCT)在共同房室通道(CAC)诊断中的应用价值.方法 选取9例CAC患儿,采用DSCT心电门控下对比增强完成心脏检查,并在图像工作站完成多平面(MPR)、最大密度投影(MIP)和三维容积漫游(VR)处理.同期所有患儿均完成超声心动图检查.比较两种检查方法的诊断结果.结果 DSCT均作出CAC诊断,共发现合并畸形29处;超声心动图亦均作出CAC诊断,共发现合并畸形16处.结论 DSCT可以对CAC患儿作出准确诊断,较之超声心动图能发现更多合并畸形,有助于临床手术方案的制定与完善.%Objective To evaluate the clinical values of dual-source CT (DSCT) in diagnosis of common atrioventricular canal. Methods Nine children aged 135 days to 6 y with common atrioventricular canal (CAC) underwent dual-source cardiac CT scan. Two- and three-dimensional images were processed by means of MPR (coronal, sagital and oblique), MIP and VR. E-chocardiography was performed in all cases at same time; and 2 cases received surgical treatment. Results DSCT confirmed diagnosis of CAC in all 9 cases. DSCT revealed 29 concomitant anomalies and echocardiography revealed 16 in all 9 cases. Conclusion DSCT can confirm diagnosis of common atrioventricular canal, which contributes to the planning of operation and better surgical outcomes of patients.

  11. Modulation and metamodulation of synapses by adenosine.

    Science.gov (United States)

    Ribeiro, J A; Sebastião, A M

    2010-06-01

    The presence of adenosine in all nervous system cells (neurones and glia) together with its intensive release following insults makes adenosine as a sort of 'regulator' of synaptic communication, leading to the homeostatic coordination of brain function. Besides the direct actions of adenosine on the neurosecretory mechanisms, to tune neurotransmitter release, adenosine receptors interact with other receptors as well as with transporters as part of its attempt to fine-tune synaptic transmission. This review will focus on examples of the different ways adenosine can use to modulate or metamodulate synapses, in other words, to trigger or brake the action of some neurotransmitters and neuromodulators, to cross-talk with other G protein-coupled receptors, with ionotropic receptors and with receptor kinases as well as with transporters. Most of these interactions occur through A2A receptors, which in spite of their low density in some brain areas, such as the hippocampus, may function as amplifiers of the signalling of other mediators at synapses.

  12. Dual-Source Dual-Energy CT for the Differentiation of Urinary Stone Composition: In Vivo Study%体内泌尿系结石的双源CT双能量成像

    Institute of Scientific and Technical Information of China (English)

    张挽时; 杨琪放; 孟利民; 郭和清; 严景民; 刘红明

    2012-01-01

    件可以较好地区分体内的尿酸结石、混合尿酸结石、胱氨酸结石和含钙结石,但区分磷酸镁铵结石以及不同成分的含钙结石尚存在困难.%Objective To evaluate the ability of dual-source dual-energy CT to differentiate urinary stone of different compositions in vivo. Methods Sixty-four patients with known urinary stone disease were scanned using a DSCT scanner in the dual-energy mode. Hounsfield units (HU) of each stone were recorded for the 80 kV and the 140 kV datasets by hand-drawing method. HU difference, HU ratio and DEI were calculated. Urinary stones were classified as UA stones, mixed UA stones, cystine stones and calcium stones based on dual energy software, the results compared with the infrared spectroscopy analysis of stone samples. Use one-way ANOVA to compare HU difference, HU ratio and DEI of different stones groups according to infrared spectroscopy. Results In 55 patients, stones were sampled. Dual energy software correctly characterized 4 UA stones, 1 mixed UA stone, 2 cystine stone, and 42 calcium stones. 4 struvite stones, 1 mixed ammonium uratc and calcium stone, 1 mixed UA stone were classified as calcium stones. Statistical differences in HU difference (18±12), (214±21), (329±35), (360±49), (458±97) and (497±110) HU respectively, HU ratio (1.04±0.02, l.36±0.02, 1.49±0.04, 1.50±0.08. 1.52±0.05 and 1.53±0.04 respectively), and DEI (0.006±0.004, 0.062±0.002, 0.089±0.006, 0.095±0.0l3, 0.107±0.011 and 0.112±0.012 respectively) among UA stones, cystine stone, stravite stones, CaP stones, CaOx stones and mix calcium stones (P<0.001). There were statistical differences in HU difference, HU ratio and DEI between UA stones and ihe other groups, in HU ratio and DEI between cystine stones and the other groups, in HU difference and DEI between struvite stones and CaOx or mix calcium stones, in HU difference between cystine stones and CaOx or mix calcium stones, in DEI between CaP stones and mix

  13. Clinical eraluation of dual-source CT enterography using dual-energy rirtual non-enhanced technique%双源 CT 小肠造影双能量虚拟平扫的临床评估

    Institute of Scientific and Technical Information of China (English)

    邓丽萍; 史晓喆; 章士正; 张峭巍

    2014-01-01

    目的:探讨64排双源 CT 小肠造影双能量虚拟平扫技术应用于临床的可行性。方法:采用双源 CT 机对39例患者进行小肠造影检查,常规行 CT 平扫以及动、静脉期对比增强双能量扫描(100 kVp/230 mAs 和 l40 kVp/178 mAs)。利用 Liver VNC 软件进行后处理,获得动、静脉期的虚拟平扫 CT 图像。以常规 CT 平扫图像作为标准,对虚拟平扫图像的质量进行评估,采用4级评分法:最高为4分(图像解剖细节清晰,完全能满足诊断),最低为1分(图像模糊,不能满足诊断)。并对常规 CT 平扫、动、静脉期双能量 CT 扫描的辐射剂量进行比较。结果:39例中有腹部病变者25例,无明显异常者14例。与常规平扫图像比较,虚拟平扫图像上所有病灶均能显示,且病灶的范围、大小亦无明显差异;两位医师对虚拟平扫图像质量的评分均>2分,两者的评分差异无统计学意义(P >0.05)。所有虚拟平扫图像完全能满足诊断要求。常规平扫、双能量动脉期、双能量静脉期扫描的剂量长度乘积(DLP)分别为(283.8750±57.1195)、(289.3750±53.1543)和(301.2917±55.3346)mGy·cm,三次扫描的 DLP 的差异无统计学意义(F =0.615,P =0.544)。结论:双源 CT 小肠造影检查时可仅进行双能量增强扫描,经后处理获得的虚拟平扫图像基本可取代常规 CT 平扫,从而可减少检查的辐射剂量。%Objectire:To investigate the clinical feasibility of dual-source CT enterography using dual-energy virtual non-enhanced CT (VNCT)technique.Methods:CT enterography were performed in 39 patients with dual source CT scan-ner,including conventional non-enhanced CT scan (CNCT),arterial and venous phase contrast-enhanced CT scan (CECT) with dual energy mode (100kVp/230mAs and 140kVp/178mAs).VNCT images of arterial and venous phase were obtained after being post

  14. Dual-energy imaging of bone marrow edema on a dedicated multi-source cone-beam CT system for the extremities

    Science.gov (United States)

    Zbijewski, W.; Sisniega, A.; Stayman, J. W.; Thawait, G.; Packard, N.; Yorkston, J.; Demehri, S.; Fritz, J.; Siewerdsen, J. H.

    2015-03-01

    Purpose: Arthritis and bone trauma are often accompanied by bone marrow edema (BME). BME is challenging to detect in CT due to the overlaying trabecular structure but can be visualized using dual-energy (DE) techniques to discriminate water and fat. We investigate the feasibility of DE imaging of BME on a dedicated flat-panel detector (FPD) extremities cone-beam CT (CBCT) with a unique x-ray tube with three longitudinally mounted sources. Methods: Simulations involved a digital BME knee phantom imaged with a 60 kVp low-energy beam (LE) and 105 kVp high-energy beam (HE) (+0.25 mm Ag filter). Experiments were also performed on a test-bench with a Varian 4030CB FPD using the same beam energies as the simulation study. A three-source configuration was implemented with x-ray sources distributed along the longitudinal axis and DE CBCT acquisition in which the superior and inferior sources operate at HE (and collect half of the projection angles each) and the central source operates at LE. Three-source DE CBCT was compared to a double-scan, single-source orbit. Experiments were performed with a wrist phantom containing a 50 mg/ml densitometry insert submerged in alcohol (simulating fat) with drilled trabeculae down to ~1 mm to emulate the trabecular matrix. Reconstruction-based three-material decomposition of fat, soft tissue, and bone was performed. Results: For a low-dose scan (36 mAs in the HE and LE data), DE CBCT achieved combined accuracy of ~0.80 for a pattern of BME spherical lesions ranging 2.5 - 10 mm diameter in the knee phantom. The accuracy increased to ~0.90 for a 360 mAs scan. Excellent DE discrimination of the base materials was achieved in the experiments. Approximately 80% of the alcohol (fat) voxels in the trabecular phantom was properly identified both for single and 3-source acquisitions, indicating the ability to detect edemous tissue (water-equivalent plastic in the body of the densitometry insert) from the fat inside the trabecular matrix

  15. Circadian variations of adenosine level in blood and liver and its possible physiological significance.

    Science.gov (United States)

    Chagoya de Sánchez, V; Hernández-Muñoz, R; Díaz-Muñoz, M; Villalobos, R; Glender, W; Vidrio, S; Suárez, J; Yañez, L

    1983-09-12

    The role of adenosine as a possible physiological modulator was explored by measuring its concentration in different tissues during a 24-hour period. Initially the circadian variations of adenosine and other purine compounds such as inosine, hypoxanthine, uric acid and adenine nucleotides were studied in the rat blood. A daily cyclic response was observed, with low levels of adenosine from 08.00 - 20.00 h, followed by an increase from this time on. Inosine and hypoxanthine levels were elevated during the day and low at night. The uric acid changes observed indicate that the decrease in purine catabolism coincides with a decrease in inosine and hypoxanthine levels and an increase in adenosine. The blood adenine nucleotides, energy charge and phosphorylation potential remained constant during the day and showed oscillatory changes during the night. Similar studies were made in the liver, a primary source of circulating purines. Liver adenosine was high during the night while inosine and hypoxanthine remained low along the 24 hours. The results suggest that liver purine metabolism might participate in the maintenance and renewal of the blood purine pool and in the energy state of erythrocytes in vivo.

  16. The role of adenosine receptors and endogenous adenosine in citalopram-induced cardiovascular toxicity

    Directory of Open Access Journals (Sweden)

    Kubilay Oransay

    2014-01-01

    Full Text Available Aim: We investigated the role of adenosine in citalopram-induced cardiotoxicity. Materials and Methods: Protocol 1: Rats were randomized into four groups. Sodium cromoglycate was administered to rats. Citalopram was infused after the 5% dextrose, 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX; A 1 receptor antagonist, 8-(-3-chlorostyryl-caffeine (CSC; A 2a receptor antagonist, or dimethyl sulfoxide (DMSO administrations. Protocol 2: First group received 5% dextrose intraperitoneally 1 hour prior to citalopram. Other rats were pretreated with erythro-9-(2-hydroxy-3-nonyl adenine (EHNA; inhibitor of adenosine deaminase and S-(4-Nitrobenzyl-6-thioinosine (NBTI; inhibitor of facilitated adenosine transport. After pretreatment, group 2 received 5% dextrose and group 3 received citalopram. Adenosine concentrations, mean arterial pressure (MAP, heart rate (HR,  QRS duration and QT interval were evaluated. Results: In the dextrose group, citalopram infusion caused a significant decrease in MAP and HR and caused a significant prolongation in QRS and QT. DPCPX infusion significantly prevented the prolongation of the QT interval when compared to control. In the second protocol, citalopram infusion did not cause a significant change in plasma adenosine concentrations, but a significant increase observed in EHNA/NBTI groups. In EHNA/NBTI groups, citalopram-induced MAP and HR reductions, QRS and QT prolongations were more significant than the dextrose group. Conclusions: Citalopram may lead to QT prolongation by stimulating adenosine A 1 receptors without affecting the release of adenosine.

  17. Identification of the nitrate contamination sources of the Brusselian sands groundwater body (Belgium) using a dual-isotope approach.

    Science.gov (United States)

    Mattern, Samuel; Sebilo, Mathieu; Vanclooster, Marnik

    2011-09-01

    Isotopic fingerprinting is an advanced technique allowing the classification of the nitrate source pollution of groundwater, but needs further development and validation. In this study, we performed measurements of natural stable isotopic composition of nitrate ((15)N and (18)O) in the groundwater body of the Brussels sands (Belgium) and studied the spatial and temporal dynamics of the isotope signature of this aquifer. Potential nitrogen sources sampled in the region had isotopic signatures that fell within the corresponding typical ranges found in the literature. For a few monitoring stations, the isotopic data strongly suggest that the sources of nitrate are from mineral fertiliser origin, as used in agriculture and golf courses. Other stations suggest that manure leaching from unprotected stockpiles in farms, domestic gardening practices, septic tanks and probably cemeteries contribute to the nitrate pollution of this groundwater body. For most monitoring stations, nitrate originates from a mixing of several nitrogen sources. The isotopic signature of the groundwater body was poorly structured in space, but exhibited a clear temporal structure. This temporal structure could be explained by groundwater recharge dynamics and cycling process of nitrogen in the soil-nitrogen pool.

  18. Dual-Energy Imaging of Urate Crystals in Gout Using Dual-Source CT%双源CT双能量成像对痛风诊断价值的初步研究

    Institute of Scientific and Technical Information of China (English)

    靳国庆; 王东林; 王振杰; 李麦福

    2013-01-01

    cases. 478 sites of urate crystal deposition were displayed. The diseased sites are most in Feet and ankles were the mostly involved site. There was no urate crystal deposition found in control group. There was significant difference between two groups on displaying urate crystal(P =0.00012,P <0.001). Conclusion Dual source DECT technology can clearly display the urate crystal deposition, which can be used as routine examination for the gout diagnosis.

  19. A model for quantitative correction of coronary calcium scores on multidetector, dual source, and electron beam computed tomography for influences of linear motion, calcification density, and temporal resolution : A cardiac phantom study

    NARCIS (Netherlands)

    Greuter, M. J. W.; Groen, J. M.; Nicolai, L. J.; Dijkstra, H.; Oudkerk, M.

    2009-01-01

    Purpose: The objective of this study is to quantify the influence of linear motion, calcification density, and temporal resolution on coronary calcium determination using multidetector computed tomography (MDCT), dual source CT (DSCT), and electron beam tomography (EBT) and to find a quantitative me

  20. A dual-inexact fuzzy stochastic model for water resources management and non-point source pollution mitigation under multiple uncertainties

    Science.gov (United States)

    Dong, C.; Tan, Q.; Huang, G.-H.; Cai, Y.-P.

    2014-05-01

    In this research, a dual-inexact fuzzy stochastic programming (DIFSP) method was developed for supporting the planning of water and farmland use management system considering the non-point source pollution mitigation under uncertainty. The random boundary interval (RBI) was incorporated into DIFSP through integrating fuzzy linear programming (FLP) and chance-constrained programming (CCP) approaches within an interval linear programming (ILP) framework. This developed method could effectively tackle the uncertainties expressed as intervals and fuzzy sets. Moreover, the lower and upper bounds of RBI are continuous random variables, and the correlation existing between the lower and upper bounds can be tackled in RBI through the joint probability distribution function. And thus the subjectivity of decision making is greatly reduced, enhancing the stability and robustness of obtained solutions. The proposed method was then applied to solve a water and farmland use planning model (WFUPM) with non-point source pollution mitigation. The generated results could provide decision makers with detailed water supply-demand schemes involving diversified water-related activities under preferred satisfaction degrees. These useful solutions could allow more in-depth analyses of the trade-offs between humans and environment, as well as those between system optimality and reliability. In addition, comparative analyses on the solutions obtained from ICCP (Interval chance-constraints programming) and DIFSP demonstrated the higher application of this developed approach for supporting the water and farmland use system planning.

  1. Design and analysis of a dual-axis resonator fiber-optic gyroscope employing a single source.

    Science.gov (United States)

    Pinnoji, Prerana Dabral; Nayak, Jagannath

    2013-08-01

    In this paper, design of a resonator fiber-optic gyroscope comprised of a single laser source and two optical fiber resonator rings is presented. A typical gyroscope measures angular rotation around a fixed axis, whereas the proposed design can sense simultaneous rotation about two orthogonal axes. Two variants of the design are proposed and analyzed using a mathematical model based on Jones matrix methodology.

  2. The role of adenosine in Alzheimer's disease.

    Science.gov (United States)

    Rahman, Anisur

    2009-09-01

    Alzheimer's disease (AD) is a neurodegenerative disorder of the central nervous system manifested by cognitive and memory deterioration, a variety of neuropsychiatric symptoms, behavioral disturbances, and progressive impairment of daily life activities. Current pharmacotherapies are restricted to symptomatic interventions but do not prevent progressive neuronal degeneration. Therefore, new therapeutic strategies are needed to intervene with these progressive pathological processes. In the past several years adenosine, a ubiquitously released purine ribonucleoside, has become important for its neuromodulating capability and its emerging positive experimental effects in neurodegenerative diseases. Recent research suggests that adenosine receptors play important roles in the modulation of cognitive function. The present paper attempts to review published reports and data from different studies showing the evidence of a relationship between adenosinergic function and AD-related cognitive deficits. Epidemiological studies have found an association between coffee (a nonselective adenosine receptor antagonist) consumption and improved cognitive function in AD patients and in the elderly. Long-term administration of caffeine in transgenic animal models showed a reduced amyloid burden in brain with better cognitive performance. Antagonists of adenosine A2A receptors mimic these beneficial effects of caffeine on cognitive function. Neuronal cell cultures with amyloid beta in the presence of an A2A receptor antagonist completely prevented amyloid beta-induced neurotoxicity. These findings suggest that the adenosinergic system constitutes a new therapeutic target for AD, and caffeine and A2A receptor antagonists may have promise to manage cognitive dysfunction in AD.

  3. Ultra-low-dose dual-source CT coronary angiography with high pitch: diagnostic yield of a volumetric planning scan and effects on dose reduction and imaging strategy

    Science.gov (United States)

    Hamm, B; Huppertz, A; Lembcke, A

    2015-01-01

    Objective: To evaluate the role of an ultra-low-dose dual-source CT coronary angiography (CTCA) scan with high pitch for delimiting the range of the subsequent standard CTCA scan. Methods: 30 patients with an indication for CTCA were prospectively examined using a two-scan dual-source CTCA protocol (2.0 × 64.0 × 0.6 mm; pitch, 3.4; rotation time of 280 ms; 100 kV): Scan 1 was acquired with one-fifth of the tube current suggested by the automatic exposure control software [CareDose 4D™ (Siemens Healthcare, Erlangen, Germany) using 100 kV and 370 mAs as a reference] with the scan length from the tracheal bifurcation to the diaphragmatic border. Scan 2 was acquired with standard tube current extending with reduced scan length based on Scan 1. Nine central coronary artery segments were analysed qualitatively on both scans. Results: Scan 2 (105.1 ± 10.1 mm) was significantly shorter than Scan 1 (127.0 ± 8.7 mm). Image quality scores were significantly better for Scan 2. However, in 5 of 6 (83%) patients with stenotic coronary artery disease, a stenosis was already detected in Scan 1 and in 13 of 24 (54%) patients with non-stenotic coronary arteries, a stenosis was already excluded by Scan 1. Using Scan 2 as reference, the positive- and negative-predictive value of Scan 1 was 83% (5 of 6 patients) and 100% (13 of 13 patients), respectively. Conclusion: An ultra-low-dose CTCA planning scan enables a reliable scan length reduction of the following standard CTCA scan and allows for correct diagnosis in a substantial proportion of patients. Advances in knowledge: Further dose reductions are possible owing to a change in the individual patient's imaging strategy as a prior ultra-low-dose CTCA scan may already rule out the presence of a stenosis or may lead to a direct transferal to an invasive catheter procedure. PMID:25710210

  4. 双源CT双步触发技术用于心脏扫描%Application of dual-step prospective ECG-triggered dual-source CT in cardiac scan

    Institute of Scientific and Technical Information of China (English)

    李强; 钱农; 钱波; 徐烈福; 孟名柱; 潘昌杰

    2013-01-01

    Objective To introduce the application of dual-step prospective ECG-triggcrcd technical of DSCT in coronary angiog-raphy and left ventricular function analysis simultaneously. Methods Fifty-three consecutive patients suspected or diagnosed with coronary disease were examined by cardiac DSCT and MRI. Sequential acquisition and dual-step prospective ECG-triggcr were used in DSCT. Full tube current output in tube A at 70% ( HR≤70 bcats/min)or 40% ( HR>70 bcats/min) R-R interval according to heart rates and 20% tube current output in tube B at 30%-90% R-R interval in all patients. The coronary artery was divided into 16 segments according to the American Heart Association. Image quality of coronary arteries were graded with 4-point scale. LVES, LVED and LVEF were evaluated in DSCT and MR]. Paired it-test and pcarson correlation were statistically analysed. Results Fifty cases accomplished examination successfully. The average radiation docs was(3. 33±0. 65) mSv. In 669 evaluated coronary segments, 97. 76% could be diagnosed . Paired it-test indicated that the LVES, LVED and LVEF of DSCT and MR] had no significant statistically differences(P = 0. 91 ,0. 12 and 0. 16)and the correlation was good (r = 0. 96,0. 97 and 0. 89). Conclusion The second generation DSCT with dual-step prospective ECG-triggcrcd sequential acquisition can be used in coronary angiography and left ventricular function analysis simultaneously with good imaging quality of the coronary artery, reliable analysis of left ventricular function and lower radiation dose.%目的 探讨第二代双源CT(dual-source CT,DSCT)双步触发技术在冠状动脉造影兼顾左心室功能分析中的应用价值.方法 连续53例临床怀疑或确诊为冠状动脉心脏病的患者行冠状动脉DSCT造影和心脏MRI检查.DSCT采用序列扫描模式,前瞻性心电门控双步触发.扫描窗宽30%~90%R-R间期,依据不同的心率,仅在70%(心率≤70次/min)或40%(心率>70次/min)R-R间期全电

  5. AMP is an adenosine A1 receptor agonist.

    Science.gov (United States)

    Rittiner, Joseph E; Korboukh, Ilia; Hull-Ryde, Emily A; Jin, Jian; Janzen, William P; Frye, Stephen V; Zylka, Mark J

    2012-02-17

    Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5'-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5'-monophosphonate, ACP) directly activated the adenosine A(1) receptor (A(1)R). In contrast, AMP only activated the adenosine A(2B) receptor (A(2B)R) after hydrolysis to adenosine by ecto-5'-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A(1)R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A(1)R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A(1)R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A(1)R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine.

  6. Adenosine: An immune modulator of inflammatory bowel diseases

    Institute of Scientific and Technical Information of China (English)

    Jeff Huaqing Ye; Vazhaikkurichi M Rajendran

    2009-01-01

    Inflammatory bowel disease (IBD) is a common and lifelong disabling gastrointestinal disease. Emerging treatments are being developed to target inflammatory cytokines which initiate and perpetuate the immune response. Adenosine is an important modulator of inflammation and its anti-inflammatory effects have been well established in humans as well as in animal models. High extracellular adenosine suppresses and resolves chronic inflammation in IBD models. High extracellular adenosine levels could be achieved by enhanced adenosine absorption and increased de novo synthesis. Increased adenosine concentration leads to activation of the A2a receptor on the cell surface of immune and epithelial cells that would be a potential therapeutic target for chronic intestinal inflammation. Adenosine is transported via concentrative nucleoside transporter and equilibrative nucleoside transporter transporters that are localized in apical and basolateral membranes of intestinal epithelial cells, respectively. Increased extracellular adenosine levels activate the A2a receptor, which would reduce cytokines responsible for chronic inflammation.

  7. Prevalence of first-pass myocardial perfusion defects detected by contrast-enhanced dual-source CT in patients with non-ST segment elevation acute coronary syndromes

    Energy Technology Data Exchange (ETDEWEB)

    Schepis, Tiziano; Achenbach, Stephan; Marwan, Mohamed; Muschiol, Gerd; Ropers, Dieter; Daniel, Werner G.; Pflederer, Tobias [University of Erlangen, Department of Internal Medicine 2 (Cardiology), Erlangen (Germany)

    2010-07-15

    To investigate the prevalence and diagnostic value of first-pass myocardial perfusion defects (PD) visualised by contrast-enhanced multidetector computed tomography (MDCT) in patients admitted for a first acute coronary syndrome (ACS). Thirty-eight patients with non-ST segment elevation myocardial infarction (NSTEMI) or unstable angina (UA) and scheduled for percutaneous coronary intervention underwent dual-source CT immediately before catheterisation. CT images were analysed for the presence of any PD by using a 17-segment model. Results were compared with peak cardiac troponin-I (cTnI) and angiography findings. PD were seen in 21 of the 24 patients with NSTEMI (median peak cTnI level 7.07 ng/mL; range 0.72-37.07 ng/mL) and in 2 of 14 patients with UA. PD corresponded with the territory of the infarct-related artery in 20 out of 22 patients. In a patient-based analysis, sensitivity, specificity, negative and positive predictive values of any PD for predicting NSTEMI were 88%, 86%, 80% and 91%. Per culprit artery, the respective values were 86%, 75%, 80% and 83%. In patients with non-ST segment elevation ACS, first-pass myocardial PD in contrast-enhanced MDCT correlate closely with the presence of myocardial necrosis, as determined by increases in cTnI levels. (orig.)

  8. Low-dose prospective ECG-triggering dual-source CT angiography in infants and children with complex congenital heart disease: first experience

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Zhaoping; Wang, Ximing; Duan, Yanhua; Wu, Lebin; Wu, Dawei; Chao, Baoting; Liu, Cheng; Xu, Zhuodong [Shandong University, Shandong Medical Imaging Research Institute, Jinan, Shandong (China); Li, Hongxin; Liang, Fei [Shandong Provincial Hospital, Department of Cardiovascular Surgery, Jinan, Shandong (China); Xu, Jian; Chen, Jiuhong [Siemens. Ltd. China, CT Research Collaboration, Beijing (China)

    2010-10-15

    To explore the clinical value of low-dose prospective ECG-triggering dual-source CT (DSCT) angiography in infants and children with complex congenital heart disease (CHD) compared with transthoracic echocardiography (TTE). Thirty-five patients (mean age: 16 months, range: 2 months to 6 years; male 15; mean weight: 12 kg) underwent low-dose prospective ECG-triggering DSCT angiography and TTE. Surgeries were performed in 29 patients, and conventional cardiac angiography (CCA) was performed in 8 patients. The accuracy was calculated based on the surgical and/or CCA findings. The overall imaging quality was evaluated on a five-point scale. A total of 146 separate cardiovascular deformities were confirmed. DSCT missed three atrial septal defects and a patent ductus arteriosus. The accuracy of DSCT angiography and TTE was 97.3% (142/146) and 92.5% (135/146), respectively. Overall test parameters for DSCT angiography and TTE were similar (sensitivity, 97.3% vs 92.5%; specificity, 99.8% vs 99.8%). The average subjective image quality score was 4.3 {+-} 0.7. The mean effective dose was 0.38 {+-} 0.09 mSv. Prospective ECG-triggering DSCT angiography with a very low effective radiation dose allows the accurate diagnosis of anomalies in infants and children with complex CHD compared with TTE. It has great promise to become a commonly used second-line technique for complex CHD. (orig.)

  9. Accuracy and variability of right ventricular volumes and mass assessed by dual-source computed tomography: influence of slice orientation in comparison to magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Christoph J. [Elisabeth Hospital Essen, Department of Cardiology and Angiology, Essen (Germany); Duke University Medical Center, Duke Cardiovascular Magnetic Resonance Center, Durham, NC (United States); Wolf, Alexander; Eberle, Holger C.; Sabin, Georg V.; Bruder, Oliver [Elisabeth Hospital Essen, Department of Cardiology and Angiology, Essen (Germany); Forsting, Michael; Nassenstein, Kai; Lauenstein, Thomas C.; Schlosser, Thomas [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany)

    2011-12-15

    To evaluate the accuracy and variability of right ventricular (RV) volumes and mass using dual-source computed tomography (DSCT) and the influence of slice orientation in comparison to cardiac magnetic resonance imaging (CMR). In 33 patients undergoing cardiac DSCT and CMR, RV parameters were calculated using the short-axis (DSCT, CMR) and axial orientation (DSCT). Intra- and interobserver variability were assessed by Bland-Altman analysis. Short-axis orientation: RV parameters of the two techniques were not statistically different. Axial orientation: RV volumes and mass were significantly overestimated compared with short-axis parameters whereas EF was similar. The short-axis approach resulted in low variability, although the axial orientation had the least amount of intra- and interobserver variability. RV parameters can be more accurately assessed by DSCT compared with CMR using short-axis slice orientation. RV volumes and mass are significantly higher using axial compared with short-axis slices, whereas EF is unaffected. RV parameters derived from both approaches yield high reproducibility. (orig.)

  10. Carotid and cerebrovascular disease in symptomatic patients with type 2 diabetes: assessment of prevalence and plaque morphology by dual-source computed tomography angiography

    Directory of Open Access Journals (Sweden)

    Deng Wen

    2010-12-01

    Full Text Available Abstract Background Plaque morphology directly correlates with risk of embolism and the recently developed dual-source computed tomography angiography (DSCTA may help to detect plaques more precisely. The aim of our study was to evaluate the prevalence and morphology of carotid and cerebrovascular atherosclerotic plaques in patients with symptomatic type 2 diabetes mellitus (DM by DSCTA. Methods From July 2009 to August 2010, DSCTA was prospectively performed in 125 consecutive patients with symptomatic type 2 DM. We retrospectively analyzed plaque type, distribution, and extensive and obstructive natures were determined for each segment for all patients. Results Atherosclerotic plaques were detected in 114 (91.2% patients. Relatively more noncalcified (45% and calcified (39% plaques and less mixed (16% plaques were observed (p st to 5th segments was observed in 67 (58.8% patients and from the 6th to 10th segments in 35 (30.7% patients. The most common site of all detected plaques was the cavernous segment. Regarding stenosis, there were significantly more nonobstructive than obstructive stenosis (91% vs. 9%, p Conclusion DSCTA detected a high prevalence of plaques in patients with symptomatic type 2 DM. A relatively high proportion of plaques were noncalcified, as well as with nonobstructive stenosis. The distribution of plaques was extensive, with the cavernous portion of ICA being the most common site.

  11. Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Sung Ho; Oh, Yu Whan; Ham, Soo Youn [Dept. of Radiology, Korea University Anam Hospital, Seoul (Korea, Republic of); Kang, Eun Young [Dept. of Radiology, Korea University Guro Hospital, Seoul (Korea, Republic of); Lee, Ki Yeol [Dept. of Radiology, Korea University Ansan Hospital, Ansan (Korea, Republic of)

    2015-06-15

    To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 +/- 0.9%, and 1.7 +/- 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 +/- 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 +/- 5.3%), with an IVV of 13.1 +/- 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size. The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.

  12. Radiation dose considerations by intra-individual Monte Carlo simulations in dual source spiral coronary computed tomography angiography with electrocardiogram-triggered tube current modulation and adaptive pitch

    Energy Technology Data Exchange (ETDEWEB)

    May, Matthias S.; Kuettner, Axel; Lell, Michael M.; Wuest, Wolfgang; Scharf, Michael; Uder, Michael [University of Erlangen, Department of Radiology, Erlangen (Germany); Deak, Paul; Kalender, Willi A. [University of Erlangen, Department of Medical Physics, Erlangen (Germany); Keller, Andrea K.; Haeberle, Lothar [University of Erlangen, Department of Medical Informatics, Biometry and Epidemiology, Erlangen (Germany); Achenbach, Stephan; Seltmann, Martin [University of Erlangen, Department of Cardiology, Erlangen (Germany)

    2012-03-15

    To evaluate radiation dose levels in patients undergoing spiral coronary computed tomography angiography (CTA) on a dual-source system in clinical routine. Coronary CTA was performed for 56 patients with electrocardiogram-triggered tube current modulation (TCM) and heart-rate (HR) dependent pitch adaptation. Individual Monte Carlo (MC) simulations were performed for dose assessment. Retrospective simulations with constant tube current (CTC) served as reference. Lung tissue was segmented and used for organ and effective dose (ED) calculation. Estimates for mean relative ED was 7.1 {+-} 2.1 mSv/100 mAs for TCM and 12.5 {+-} 5.3 mSv/100 mAs for CTC (P < 0.001). Relative dose reduction at low HR ({<=}60 bpm) was highest (49 {+-} 5%) compared to intermediate (60-70 bpm, 33 {+-} 12%) and high HR (>70 bpm, 29 {+-} 12%). However lowest ED is achieved at high HR (5.2 {+-} 1.5 mSv/100 mAs), compared with intermediate (6.7 {+-} 1.6 mSv/100 mAs) and low (8.3 {+-} 2.1 mSv/100 mAs) HR when automated pitch adaptation is applied. Radiation dose savings up to 52% are achievable by TCM at low and regular HR. However lowest ED is attained at high HR by pitch adaptation despite inferior radiation dose reduction by TCM. circle Monte Carlo simulations allow for individual radiation dose calculations. (orig.)

  13. The value of low-dose prospective ECG-gated dual-source CT angiography in the diagnosis of coarctation of the aorta in infants and children

    Energy Technology Data Exchange (ETDEWEB)

    Nie, P. [Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong (China); Wang, X., E-mail: wxming369@yahoo.com.cn [Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong (China); Cheng, Z.; Duan, Y.; Ji, X. [Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong (China); Chen, J. [CT Research Collaboration, Siemens, Beijing (China); Zhang, H. [Department of Cardiovascular Surgery, Shandong Provincial Hospital, Jinan, Shandong (China)

    2012-08-15

    Aim: To investigate the value of prospective electrocardiogram (ECG)-gated dual-source computed tomography (DSCT) in the diagnosis of coarctation of the aorta (CoA). Materials and methods: Seventeen patients clinically suspected of having CoA underwent prospective ECG-gated DSCT angiography and transthoracic echocardiography (TTE). Surgery was performed in all patients. The diagnostic accuracy of DSCT angiography and TTE was compared with the surgical findings as the reference standard. Image quality was evaluated using a five-point scale. Effective radiation dose was calculated from the dose-length product (DLP). Results: CoA was diagnosed in 17 patients by DSCT angiography and in 16 patients by TTE. A total of 46 separate cardiovascular abnormalities were confirmed by surgical findings. The diagnostic accuracy of DSCT angiography and TTE was 96.32% and 97.06%, respectively. There was no significant difference in the diagnostic accuracy between DSCT angiography and TTE ({chi}{sup 2} = 0, p > 0.05). The mean score of image quality was 4.2 {+-} 0.8. The mean effective dose was 0.69 {+-} 0.09 mSv. Conclusion: Prospective ECG-gated DSCT with a low radiation dose is a valuable technique in the diagnosis of CoA in infants and children.

  14. 双源制机车基础制动装置的研制%Development of Brake Rigging Device for The Dual -source Electric Locomotive

    Institute of Scientific and Technical Information of China (English)

    杨威; 艾正武; 李金花; 刘德学

    2013-01-01

      针对双源制机车基础制动装置安装空间小的特点,提出一种新的紧凑型踏面单元制动器。介绍了该单元制动器的结构、工作原理及相关技术参数,重点阐述和分析了间隙调整器的原理,通过对紧急制动距离、停放制动力校核计算,验证了该踏面单元制动器能满足双源制电力机车的制动要求。%In order to meet the characteristics of a small installation space of foundation brake for dual -source electric locomotive ,a new compact tread brake unit is presented in this paper .The paper introduces the structure ,working principle and technical parameter of the tread brake unit ,which focuses on the principle of the slack adjuster .According to the calculation of the emergency braking dis-tance and park brake force ,it is verified that the tread brake unit can meet the braking requirements of the electric locomotive .

  15. Initial results of a new generation dual source CT system using only an in-plane comb filter for ultra-high resolution temporal bone imaging

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Mathias; Haubenreisser, Holger; Schoenberg, Stefan O.; Henzler, Thomas [Heidelberg University, Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Mannheim (Germany); Raupach, Rainer; Schmidt, Bernhard; Leidecker, Christianne; Allmendinger, Thomas; Flohr, Thomas [Siemens Healthcare, Imaging and Therapy Division, Forchheim (Germany); Lietzmann, Florian; Schad, Lothar R. [Heidelberg University, Computer Assisted Clinical Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Mannheim (Germany)

    2015-01-15

    To prospectively evaluate radiation dose and image quality of a third generation dual-source CT (DSCT) without z-axis filter behind the patient for temporal bone CT. Forty-five patients were either examined on a first, second, or third generation DSCT in an ultra-high-resolution (UHR) temporal bone-imaging mode. On the third generation DSCT system, the tighter focal spot of 0.2 mm{sup 2} removesthe necessity for an additional z-axis-filter, leading to an improved z-axis radiation dose efficiency. Images of 0.4 mm were reconstructed using standard filtered-back-projection or iterative reconstruction (IR) technique for previous generations of DSCT and a novel IR algorithm for the third generation DSCT. Radiation dose and image quality were compared between the three DSCT systems. The statistically significantly highest subjective and objective image quality was evaluated for the third generation DSCT when compared to the first or second generation DSCT systems (all p < 0.05). Total effective dose was 63 %/39 % lower for the third generation examination as compared to the first and second generation DSCT. Temporal bone imaging without z-axis-UHR-filter and a novel third generation IR algorithm allows for significantly higher image quality while lowering effective dose when compared to the first two generations of DSCTs. (orig.)

  16. Prospectively ECG-triggered sequential dual-source coronary CT angiography in patients with atrial fibrillation: comparison with retrospectively ECG-gated helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Lei; Yang, Lin; Zhang, Zhaoqi [Capital Medical University, Department of Radiology, Beijing Anzhen Hospital, Beijing (China); Wang, Yining; Jin, Zhengyu [Chinese Academy of Medical Sciences, Department of Radiology, Peking Union Medical College Hospital, Beijing (China); Zhang, Longjiang; Lu, Guangming [Nanjing University, Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing, Jiangsu (China)

    2013-07-15

    To investigate the feasibility of applying prospectively ECG-triggered sequential coronary CT angiography (CCTA) to patients with atrial fibrillation (AF) and evaluate the image quality and radiation dose compared with a retrospectively ECG-gated helical protocol. 100 patients with persistent AF were enrolled. Fifty patients were randomly assigned to a prospective protocol and the other patients to a retrospective protocol using a second-generation dual-source CT (DS-CT). Image quality was evaluated using a four-point grading scale (1 = excellent, 2 = good, 3 = moderate, 4 = poor) by two reviewers on a per-segment basis. The coronary artery segments were considered non-diagnostic with a quality score of 4. The radiation dose was evaluated. Diagnostic segment rate in the prospective group was 99.4 % (642/646 segments), while that in the retrospective group was 96.5 % (604/626 segments) (P < 0.001). Effective dose was 4.29 {+-} 1.86 and 11.95 {+-} 5.34 mSv for each of the two protocols (P < 0.001), which was a 64 % reduction in the radiation dose for prospective sequential imaging compared with retrospective helical imaging. In AF patients, prospectively ECG-triggered sequential CCTA is feasible using second-generation DS-CT and can decrease >60 % radiation exposure compared with retrospectively ECG-gated helical imaging while improving diagnostic image quality. (orig.)

  17. Non-enhanced Low-tube-voltage High-pitch Dual-source Computed Tomography with Sinogram Affirmed Iterative Reconstruction Algorithm of the Abdomen and Pelvis

    Institute of Scientific and Technical Information of China (English)

    Liang Zhu

    2014-01-01

    Objective To investigate the image quality, radiation dose and diagnostic value of the low-tube-voltage high-pitch dual-source computed tomography (DSCT) with sinogram affirmed iterative reconstruction (SAFIRE) for non-enhanced abdominal and pelvic scans. Methods This institutional review board-approved prospective study included 64 patients who gave written informed consent for additional abdominal and pelvic scan with DSCT in the period from November to December 2012. The patients underwent standard non-enhanced CT scans (protocol 1) [tube voltage of 120 kVp/pitch of 0.9/filtered back-projection (FBP) reconstruction] followed by high-pitch non-enhanced CT scans (protocol 2) (100 kVp/3.0/SAFIRE). The total scan time, mean CT number, signal-to-noise ratio (SNR), image quality, lesion detectability and radiation dose were compared between the two protocols. Results The total scan time of protocol 2 was significantly shorter than that of protocol 1 (1.4±0.1 seconds vs. 7.6±0.6 seconds, P Conclusion The high-pitch DSCT with SAFIRE can shorten scan time and reduce radiation dose while preserving image quality in non-enhanced abdominal and pelvic scans.

  18. Assessing sources of nitrate contamination in the Shiraz urban aquifer (Iran) using the δ(15)N and δ(18)O dual-isotope approach.

    Science.gov (United States)

    Amiri, Haleh; Zare, Mohammad; Widory, David

    2015-01-01

    Nitrate ([Formula: see text]) is one of the major threats to the quality of the drinking water taken from the Shiraz aquifer. This aquifer undergoes high anthropogenic pressures from multiple local urban (including uncontrolled sewage systems), agricultural and industrial activities, resulting in [Formula: see text] concentrations as high as 149 mg L(-1), well above the 50 mg L(-1) guideline defined by the World Health Organisation. We coupled here classical chemical and dual isotope (δ(15)N and δ(18)O of [Formula: see text]) approaches trying to characterize sources and potential processes controlling the budget of this pollutant. Chemical data indicate that nitrate in this aquifer is explained by distinct end-members: while mineral fertilizers isotopically show to have no impact, our isotope approach identifies natural soil nitrification and organic [Formula: see text] (manure and/or septic waste) as the two main contributors. Isotope data suggest that natural denitrification may occur within the aquifer, but this conclusion is not supported by the study of other chemical parameters.

  19. Clinical application of dual-source computed tomography in diagnosis and treatment of tumor in the oral and maxillofacial region%双源CT在颌面部肿瘤诊疗中的临床应用

    Institute of Scientific and Technical Information of China (English)

    郭照中; 刘学; 张恒; 李焱; 王杨; 孙辉

    2012-01-01

    目的:探讨双源CT(Dual-source computed tomography,DSCT)在颌面部肿瘤诊疗中的应用价值.方法:7例颌面部肿瘤病人通过双源CT检查,将数据发送至工作站进行多平面重建、容积重建.结果,7例患者均经手术治疗,术中所见肿瘤部位与周围神经、血管、软组织及硬组织关系均与双源CT检查结果一致.结论:双源CT具有扫描速度快,图像清晰的特点,在工作站上三维影像可以任意旋转和切割,从不同角度观察肿瘤与周边血管、神经、软组织及硬组织的关系,为诊断和治疗提供了大量准确信息.%Objective: To evaluate the clinical values of the Dual-source computed tomography for diagnosis and treatment in maxillofacial tumors. Method: 7 cases of maxillofacial tumors were examined with Dual-source computed tomography and then the images were taken with multi-planar reformats and volume rendering technique on work-station. Result: All the patients have been operated. Conclusion: Dual-source CT can be provided with characteristic of ultrafast speed scan and clear images. Three-dimensional CT images were obtained from circumgyration and incision at will on work-station.Pathological changes could be observed from many projection in 3D images. Dual-source CT can offer a lot of information for constitution plan of treatment. Dual-source CT is a valuable method in diagnosis and treatment of facial fractures, and the combination of 2D-CT and 3D-CT would be the best demonstration.

  20. Aminopyrimidine derivatives as adenosine antagonists / Janke Kleynhans

    OpenAIRE

    Kleynhans, Janke

    2013-01-01

    Aims of this project - The aim of this study was to design and synthesise novel 2-aminopyrimidine derivatives as potential adenosine A1 and A2A receptor antagonists. Background and rationale - Parkinson’s disease is the second most common neurodegenerative disorder (after Alzheimer’s disease) and is characterised by the selective death of the dopaminergic neurons of the nigro-striatal pathway. Distinctive motor symptoms include bradykinesia, muscle rigidity and tremor, while non-m...

  1. Dual stable isotopic analysis of nitrogen and oxygen to evaluate sources and sinks of atmospheric anthropogenic nitrate in the Colorado Desert

    Science.gov (United States)

    Bell, M. D.; Allen, E. B.; Sickman, J. O.

    2010-12-01

    Industrial, automotive, and agricultural emissions release nitrogen into the atmosphere which is subsequently deposited to the surrounding terrestrial ecosystem. The Colorado Desert is impacted by nitrogen deposition from the west due to inputs from the Los Angeles air basin as well as nearby sources from agriculture in the Coachella Valley (CV). Current research within the Colorado Desert has demonstrated that anthropogenic N deposition contributes to the increased biomass of exotic invasive grasses, which compete with native species and can create enough biomass to carry fire in areas of high deposition. To measure the anthropogenic nitrogen within the CV, an array of passive air samplers was erected spanning the valley from west to east. Each sampler contained filters to passively collect both nitric acid and ammonia ions. To evaluate the degree to which the local ecosystem is supplemented by atmospheric N and determine how nitrogen pools are transformed, surface soil and leaf tissue of the dominant shrub, Larrea tridentata, were collected at each site. Only nitrate data from the samplers has currently been analyzed. δ15N, δ17O, and δ18O were obtained from atmospheric and 1M KCl soil extracts using dual isotopic analysis of NO3-. δ15N of vegetation was obtained through combustion of dried leaf tissue. The highest concentrations of atmospheric nitrate are located on the western edge of the desert in the direction toward Los Angeles, and there is also high nitrate near the Salton Sea. The isoscape produced by the isotopic analysis provides a map further describing how NO3- molecules are moving through the desert. This map shows which sources are influencing deposition sinks across the valley. Soil concentrations of nitrogen increase along the same gradient and have an inverse relationship with δ15N. Plant tissue is also less enriched in δ15N at high deposition sites, which correlates with soil values and may be caused by increased fractionation of nitrogen

  2. Application of fusion of coincidence PET/CT image and dual source CT image in diagnosis of tumors%经济型PET/CT与双源CT异机融合在肿瘤诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    苏雪娟; 鲍红梅; 刘帆; 李运奇; 高琼

    2012-01-01

    Objective To explore the value of fusion of coincidence PET/CT image and dual source CT image in comparison of fused imaging quality. Methods Integration of coincidence PET/CT PET images with dual source CT images was performed in 29 cases with suspected tumor or tumor recurrence or metastasis, and the image quality was compared with that of PET/CT in fused images. Results Forty-six primary or metastic tumors were detected by both methods. The image quality in fused imaging of stand-alone coincidence PET/CT with dual source CT was better than that of coincidence PET/CT in fused images (X2 = 14. 743, P<0. 001). Conclusion The integration of stand-alone coincidence PET/CT and dual source CT is convenient and practical,having complementary advantages, which may improve image quality and help clinical diagnosis and treatment of tumors.%目的 通过对比分析经济型PET/CT与双源CT异机融合的图像质量,探讨异机融合的临床应用价值.方法 对29例可疑肿瘤或肿瘤复发转移患者行经济型PET/CT的PET与双源CT图像融合,并与同机融合图像质量进行对比分析.结果 两种方法均检出原发灶和转移灶共46个,异机融合图像质量优于同机融合(x2=14.743,P<0.001).结论 双源CT与经济型PET/CT异机融合,方便实用,优势互补,可提高图像质量,对临床诊断和治疗肿瘤有重要价值.

  3. Dual Rectangles

    CERN Document Server

    Everest, Graham

    2009-01-01

    This article has been written for an educational magazine whose target audience consists of students and teachers of mathematics in universities, colleges and schools. It concerns a notion of duality between rectangles. A proof is given that only finitely many integral sided pairs of dual rectangles exist. Then a geometrical group law is shown to hold on the set of all rational self-dual rectangles. Finally, the arithmetic of a cubic surface is used to construct new pairs of rational dual rectangles from old, a technique inspired by the theory of elliptic curves.

  4. 双源CT对主动脉病变的诊断价值%Diagnostic Value of Dual Source CT Angiography in Aortic Disease

    Institute of Scientific and Technical Information of China (English)

    朱建国; 郭亮

    2015-01-01

    Objective To explore the value of the dual-source CT angiography (DSCT) in diagnosis of aortic disease. Methods 90 patients were suspected aortic disease with CTA, raw data were dealt with multiplanar reformation (MPR), curved planar reformation (CPR), maximum intensity projection (MIP) and volume rendering (VR). Results The aortic disease in 90 cases included aortic dissection 27 cases, aortic aneurysm 14 cases, takayasu arteritis 3 cases, atherosclerotic 15 cases, aortic ulcer 5 cases, aortic intramural hematoma 5 cases, aortic coarctation 1 case, aortic variations 1 case, portal spongy degeneration 1 case, Budd-Chiari Syndrome 1 case, superior mesenteric arterial thrombosis 2 cases, portal thrombosis 1 case, left renal artery aneurysms 1 case, splenic artery aneurysms 1 case, pulmonary embolism 4 cases, renal cancer 1 case, normal aortic 7 cases. All the image quality is excellent, and the average effective radiation dose was 3.14 mSv. Conclusion Dual-source CT angiography is significant in diagnosing aortic disease, and can reduce radiation dose.%目的:探讨双源CT扫描血管成像对主动脉病变的诊断价值。方法对临床可疑主动脉病变的90例患者采用双源CT血管造影(CTA)检查,并对原始数据采用多平面重建(MPR)、曲面重建(CPR)、最大密度投影(MIP)和容积再现(VR)后处理技术进行重建。结果90例患者中共检出主动脉夹层27例,主动脉瘤14例,大动脉炎3例,主动脉粥样硬化15例,主动脉壁溃疡5例,主动脉壁内血肿5例,主动脉缩窄1例,主动脉变异1例,门静脉海绵样变性1例,布加氏综合征1例,肠系膜上动脉血栓2例,门静脉血栓1例,左肾动脉瘤1例,脾动脉瘤1例,肺动脉血栓4例,肾癌1例,正常7例。所有图像质量优良,有效射线剂量平均约3.14 mSv。结论双源CT扫描对主动脉病变的诊断具有重要意义,并能降低辐射剂量。

  5. 急性主动脉夹层诊断中双源CT检查的应用价值评述%Comment on the Application Value of Dual Source CT in Diagnosis of Acute Aortic Dissection

    Institute of Scientific and Technical Information of China (English)

    陈说

    2015-01-01

    目的:探析双源CT检查在急性主动脉夹层诊断中的运用价值。方法选择120例急性主动脉夹层患者为研究对象,回顾性分析其临床资料。结果双源CT诊断急性主动脉夹层的特异度和敏感度均为100%;同时MPR与VR和MIP在综合显示能力方面比较差异有统计学意义(P<0.05)。结论双源CT诊断急性主动脉夹层具有较高的准确率。%Objective To explore dual-source CT examination in the diagnosis of acute aortic dissection using value. Methods 120 cases of patients with acute aortic dissection were chosen as the research object, the clinical data were retrospectively analyzed. Results The degree of dual-source CT in the diagnosis of acute aortic dissection of the specific and sensitivity was 100%, meanwhile MPR and VR and MIP in the aspect of the comprehensive ability was statistically signiifcant (P<0.05). Conclusion Dual-source CT in the diagnosis of acute aortic dissection has higher accuracy.

  6. [The involvement of adenosine and adenosine deaminase in experimental myocardial infarct].

    Science.gov (United States)

    Stratone, A; Busuioc, A; Roşca, V; Bazgan, L; Popa, M; Hăulică, I

    1989-01-01

    By the ligature of the left coronary artery in the rat anesthetized with nembutal (10 mg/100 i.p.) a significant increase of the 5'-nucleotidase activity (Wooton method) was noticed 10 minutes after the left ventricle infarction (from an average value of 1038.5 +/- 187 mU/g tissue to 1537 +/- 225 mU/g fresh tissue). The adenosine desaminase levels spectrophotometrically determined by Denstedt technique, do not appear significantly modified 10 or 30 minutes after the left ventricle infarction. The chromatographically determined adenosine levels, by HPLC technique, decrease from the average value of 11.63 +/- 1.4 micrograms/mg PT to 8.60 +/- 1.0 micrograms/mg PT 30 minutes after infarction. The observed changes are explained by the conditions of hypoxia in the infarcted ventricle which lead to the raise in adenosine levels by activating the 5'-nucleotidase and their depression by a very fast metabolism of the same substance.

  7. Radiation exposure and image quality in staged low-dose protocols for coronary dual-source CT angiography: a randomized comparison

    Energy Technology Data Exchange (ETDEWEB)

    Pflederer, Tobias; Jakstat, Josy; Marwan, Mohamed; Schepis, Tiziano; Bachmann, Sven; Muschiol, Gerd; Ropers, Dieter; Daniel, Werner G.; Achenbach, Stephan [University of Erlangen, Department of Internal Medicine 2, Erlangen (Germany); Kuettner, Axel; Anders, Katharina; Lell, Michael [University of Erlangen, Institute of Diagnostic Radiology, Erlangen (Germany)

    2010-05-15

    To evaluate staged low-dose approaches for coronary CT angiography (CTA) in which a standard sequence was added if the low-dose sequence did not allow reliable rule-out of coronary stenosis. A total of 176 consecutive patients referred for dual-source CTA were randomized to three protocols: group 1 using prospective ECG-triggering (100 kV, 330 mAs), group 2 a retrospectively gated ''MinDose'' sequence (100 kV, 330 mAs) and group 3 a standard spiral sequence (120 kV, 400 mAs). If image quality in low-dose groups 1 or 2 was non-diagnostic, an additional standard CT examination (as in group 3) was performed. Non-diagnostic image quality was found in 11/56, 4/55, and 2/65 patients (46/896, 4/880 and 3/1,040 coronary segments) in groups 1, 2 and 3, respectively. Median (interquartile ranges) volumes of contrast material, CTDI{sub vol}, DLP and effective dose for low-dose groups 1 and 2 and for standard group 3 were 92.5 (11.3), 75.0 (2.5) and 75.0 (9.0) ml; 8.0 (1.4), 16.8 (4.8) and 48.1 (14.2) mGy; 108.0 (27.3), 246.0 (93.0) and 701.0 (207.8) mGy cm; and 1.5 (0.4), 3.4 (1.3) and 9.8 (2.9) mSv, respectively. A staged coronary CTA protocol with an initial low-dose approach and addition of a standard sequence - should image quality be too low - can lead to a substantial reduction in radiation exposure. (orig.)

  8. Prospectively ECG-triggered high-pitch spiral acquisition for coronary CT angiography using dual source CT: technique and initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Lell, Michael; Anders, Katharina [University of Erlangen, Diagnostic Radiology, Erlangen (Germany); Marwan, Mohamed; Schepis, Tiziano; Pflederer, Tobias; Kuettner, Axel; Ropers, Dieter; Daniel, Werner G.; Achenbach, Stephan [University of Erlangen, Department of Cardiology, Erlangen (Germany); Flohr, Thomas [CT Division, Siemens Healthcare, Forchheim (Germany); Eberhard-Karls-University, Institute of Diagnostic Radiology, Tuebingen (Germany); Allmendinger, Thomas; Thierfelder, Carsten [CT Division, Siemens Healthcare, Forchheim (Germany); Kalender, Willi; Ertel, Dirk [University of Erlangen, Institute of Medical Physics, Erlangen (Germany)

    2009-11-15

    We evaluated radiation exposure and image quality of a new coronary CT angiography protocol, high-pitch spiral acquisition, using dual source CT (DSCT). Coronary CTA was performed in 25 consecutive patients with a stable heart rate of 60 bpm or less after premedication, using 2 x 128 0.6-mm sections, 38.4-mm collimation width and 0.28-s rotation time. Tube settings were 100 kV/320 mAs and 120 kV/400 mAs for patients below and above 100-kg weight, respectively. Data acquisition was prospectively ECG-triggered at 60% of the R-R interval using a pitch of 3.2 (3.4 for the last 10 patients). Images were reconstructed with 75-ms temporal resolution, 0.6-mm slice thickness and 0.3-mm increment. Image quality was evaluated using a four-point scale (1 = excellent, 4 = unevaluable). Mean range of data acquisition was 113 {+-} 22 mm, mean duration was 268 {+-} 23 ms. Of 363 coronary artery segments, 327 had an image quality score of 1, and only 2 segments were rated as ''unevaluable''. Mean dose-length product (DLP) was 71 {+-} 23 mGy cm, mean effective dose was 1.0 {+-} 0.3 mSv (range 0.78-2.1 mSv). For 21 patients with a body weight below 100 kg, mean DLP was 63 {+-} 5 mGy cm (0.88 {+-} 0.07 mSv; range 0.78-0.97 mSv). Prospectively ECG-triggered high-pitch spiral CT acquisition provides high and stable image quality at very low radiation dose. (orig.)

  9. Diagnostic Value of Prospective Electrocardiogram-triggered Dual-source Computed Tomography Angiography for Infants and Children with Interrupted Aortic Arch

    Institute of Scientific and Technical Information of China (English)

    Hai-Ou Li; Xi-Ming Wang; Pei Nie; Xiao-Peng Ji; Zhao-Ping Cheng; Jiu-Hong Chen; Zhuo-Dong Xu

    2015-01-01

    Background:Accurate assessment of intra-as well as extra-cardiac malformations and radiation dosage concerns are especially crucial to infants and children with interrupted aortic arch (IAA).The purpose of this study is to investigate the value of prospective electrocardiogram (ECG)-triggered dual-source computed tomography (DSCT) angiography with low-dosage techniques in the diagnosis of IAA.Methods:Thirteen patients with suspected IAA underwent prospective ECG-triggered DSCT scan and transthoracic echocardiography (TTE).Surgery was performed on all the patients.A five-point scale was used to assess image quality.The diagnostic accuracy ofDSCT angiography and TTE was compared with the surgical findings as the reference standard.A nonparametric Chi-square test was used for comparative analysis.P<0.05 was considered as a significant difference.The mean effective radiation dose (ED) was calculated.Results:Diagnostic DSCT images were obtained for all the patients.Thirteen IAA cases with 60 separate cardiovascular anomalies were confirmed by surgical findings.The diagnostic accuracy of TTE and DSCT for total cardiovascular malformations was 93.7% and 97.9% (P>0.05),and that for extra-cardiac vascular malformations was 92.3% and 99.0% (P < 0.05),respectively.The mean score of image quality was 3.77 ± 0.83.The mean ED was 0.30 ± 0.04 mSv (range from 0.23 mSv to 0.39 mSv).Conclusions:In infants and children with IAA,prospective ECG-triggered DSCT with low radiation exposure and high diagnostic efficiency has higher accuracy compared to TTE in detection of extra-cardiac vascular anomalies.

  10. Unenhanced third-generation dual-source chest CT using a tin filter for spectral shaping at 100 kVp

    Energy Technology Data Exchange (ETDEWEB)

    Haubenreisser, Holger, E-mail: holger.haubenreisser@medma.uni-heidelberg.de [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Meyer, Mathias; Sudarski, Sonja [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Allmendinger, Thomas [Siemens Healthcare Sector, CT Division, Forchheim (Germany); Schoenberg, Stefan O.; Henzler, Thomas [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany)

    2015-08-15

    Highlights: • Spectral shaping can be done using an additional tin filter. • Spectral shaping can lead to a significantly lower dose for non-contrast CT. • The low dose protocol maintains sufficient image quality for diagnosis. • The protocol used should be used for non-contrast enhanced chest CT when possible. - Abstract: Objective: To prospectively investigate image quality and radiation dose of 100 kVp spectral shaping chest CT using a dedicated tin filter on a 3rd generation dual-source CT (DSCT) in comparison to standard 100 kVp chest CT. Methods: Sixty patients referred for a non-contrast chest on a 3rd generation DSCT were prospectively included and examined at 100 kVp with a dedicated tin filter. These patients were retrospectively matched with patients that were examined on a 2nd generation DSCT at 100 kVp without tin filter. Objective and subjective image quality was assessed in various anatomic regions and radiation dose was compared. Results: Radiation dose was decreased by 90% using the tin filter (3.0 vs 0.32 mSv). Soft tissue attenuation and image noise was not statistically different for both examination techniques (p > 0.05), however image noise was found to be significantly higher in the trachea when using the additional tin filter (p = 0.002). SNR was found to be statistically similar in pulmonary tissue, significantly lower when measured in air and significantly higher in the aorta for the scans on the 3rd generation DSCT. Subjective image quality with regard to overall quality and image noise and sharpness was not statistically significantly different (p > 0.05). Conclusion: 100 kVp spectral shaping chest CT by means of a tube-based tin-filter on a 3rd generation DSCT allows 90% dose reduction when compared to 100 kVp chest CT on a 2nd generation DSCT without spectral shaping.

  11. Update on multidetector coronary CT angiography of coronary stents: in vitro evaluation of 29 different stent types with dual-source CT.

    Science.gov (United States)

    Maintz, David; Burg, Matthias C; Seifarth, Harald; Bunck, Alexander C; Ozgün, Murat; Fischbach, Roman; Jürgens, Kai Uwe; Heindel, Walter

    2009-01-01

    The aim of this study was to test a large sample of the latest coronary artery stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation, and image noise in dual-source multidetector row CT (DSCT) in vitro and to provide a CT catalogue of currently used coronary artery stents. Twenty-nine different coronary artery stents (19 steel, 6 cobalt-chromium, 2 tantalum, 1 iron, 1 magnesium) were examined in a coronary artery phantom (vessel diameter 3 mm, intravascular attenuation 250 HU, extravascular density -70 HU). Stents were imaged in axial orientation with standard parameters: 32 x 0.6 collimation, pitch 0.24, 400 mAs, 120 kV, rotation time 0.33 s. Image reconstructions were obtained with four different convolution kernels (soft, medium-soft, standard high-resolution, stent-dedicated). To evaluate visualization characteristics of the stent, the lumen diameter, intraluminal density, and noise were measured. The stent-dedicated kernel offered best average lumen visualization (54 +/- 8.3%) and most realistic lumen attenuation (222 +/- 44 HU) at the expense of increased noise (23.9 +/- 1.9 HU) compared with standard CTA protocols (p magnesium stent showed the least artifacts with a lumen visibility of 90%. The majority of stents (79%) exhibited a lumen visibility of 50-59%. Less than half of the stent lumen was visible in only six stents. Stent lumen visibility largely varies depending on the stent type. Magnesium is by far more favorable a stent material with regard to CT imaging when compared with the more common materials steel, cobalt-chromium, or tantalum. The magnesium stent exhibits a lumen visibility of 90%, whereas the majority of the other stents exhibit a lumen visibility of 50-59%.

  12. Update on multidetector coronary CT angiography of coronary stents: in vitro evaluation of 29 different stent types with dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Maintz, David; Burg, Matthias C.; Seifarth, Harald; Bunck, Alexander C.; Oezguen, Murat; Juergens, Kai Uwe; Heindel, Walter [University of Muenster, Department of Clinical Radiology, Muenster (Germany); Fischbach, Roman [University of Muenster, Department of Clinical Radiology, Muenster (Germany); Asklepios Klinikum Altona, Department of Radiology and Nuclear Medicine, Hamburg (Germany)

    2009-01-15

    The aim of this study was to test a large sample of the latest coronary artery stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation, and image noise in dual-source multidetector row CT (DSCT) in vitro and to provide a CT catalogue of currently used coronary artery stents. Twenty-nine different coronary artery stents (19 steel, 6 cobalt-chromium, 2 tantalum, 1 iron, 1 magnesium) were examined in a coronary artery phantom (vessel diameter 3 mm, intravascular attenuation 250 HU, extravascular density -70 HU). Stents were imaged in axial orientation with standard parameters: 32 x 0.6 collimation, pitch 0.24, 400 mAs, 120 kV, rotation time 0.33 s. Image reconstructions were obtained with four different convolution kernels (soft, medium-soft, standard high-resolution, stent-dedicated). To evaluate visualization characteristics of the stent, the lumen diameter, intraluminal density, and noise were measured. The stent-dedicated kernel offered best average lumen visualization (54{+-}8.3%) and most realistic lumen attenuation (222{+-}44 HU) at the expense of increased noise (23.9{+-}1.9 HU) compared with standard CTA protocols (p<0.001 for all). The magnesium stent showed the least artifacts with a lumen visibility of 90%. The majority of stents (79%) exhibited a lumen visibility of 50-59%. Less than half of the stent lumen was visible in only six stents. Stent lumen visibility largely varies depending on the stent type. Magnesium is by far more favorable a stent material with regard to CT imaging when compared with the more common materials steel, cobalt-chromium, or tantalum. The magnesium stent exhibits a lumen visibility of 90%, whereas the majority of the other stents exhibit a lumen visibility of 50-59%. (orig.)

  13. Diagnostic accuracy of dual-source CT coronary angiography in a population unselected for degree of coronary artery calcification and without heart rate modification

    Energy Technology Data Exchange (ETDEWEB)

    Lin, C.-J., E-mail: bcjlin@gmail.co [Department of Medical Imaging, Far Eastern Memorial Hospital, Pan-Chiao, Taiwan (China); National Yang-Ming University School of Medicine, Taipei, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Hsu, J.-C. [National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Division of Cardiovascular Medicine, Far Eastern Memorial Hospital, Pan-Chiao City, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Lai, Y.-J. [Department of Medical Imaging, Far Eastern Memorial Hospital, Pan-Chiao, Taiwan (China); National Yang-Ming University School of Medicine, Taipei, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Wang, K.-L. [Department of Medical Imaging, Far Eastern Memorial Hospital, Pan-Chiao, Taiwan (China); Department of Radiological Technology, Yuanpei University, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Lee, J.-Y. [Department of Medical Imaging, Far Eastern Memorial Hospital, Pan-Chiao, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Li, A.-H. [Division of Cardiovascular Medicine, Far Eastern Memorial Hospital, Pan-Chiao City, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Chu, S.-H. [Division of Cardiovascular Surgery, Cardiovascular Center, Far Eastern Memorial Hospital, Pan-Chiao City, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China)

    2010-02-15

    Aim: To assess the ability of coronary angiography performed using dual-source computed tomography (DSCT) to evaluate coronary artery disease (CAD) in a population with unselected heart rates and extensive coronary calcification. Materials and methods: Forty-four patients at intermediate to high risk for CAD underwent both DSCT coronary angiography and invasive coronary angiography (ICA) within 30 days. No beta blockers were administered prior to imaging. Image quality and quantitatively stenosis of all coronary segments with a diameter >=1.5 mm were accessed. Patients were stratified according to mean heart rate (<70 versus >=70 bpm) and heart rate variability (<10 versus >=10 bpm). DSCT detection of coronary stenosis by segment, vessel, and patient characteristics were compared to the reference standard of ICA. Results: Diagnostic accuracy for all patients was high regarding sensitivity (97%), positive predictive value (PPV, 84.2%), and negative predictive value (NPV, 83.3%) but low regarding specificity (45.5%) with a moderate interobserver agreement (Kappa = 0.50). The accuracy for vessel-based diagnosis was high regarding sensitivity (96.6%), specificity (80.8%), PPV (80.3%), and NPV (96.7%). The segment-based diagnostic results revealed a moderate interobserver agreement for image quality and sensitivity, specificity, PPV and NPV for all segments of 66.9, 97.8, 90.8, and 89.9%, respectively. Conclusion: DSCT coronary angiography has high diagnostic accuracy in assessing CAD among patients at intermediate to high risk without using heart rate-modulating premedication. DSCT is not superior to ICA for diagnosis of calcified segments.

  14. Prospective versus retrospective ECG gating for dual source CT of the coronary stent: Comparison of image quality, accuracy, and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Lei, E-mail: zhaolei219@sohu.com [Beijing Anzhen Hospital of the Capital University of Medical Sciences (China); Zhang Zhaoqi; Fan Zhanming; Yang Lin; Du Jing [Beijing Anzhen Hospital of the Capital University of Medical Sciences (China)

    2011-03-15

    Objective: To compare image quality, diagnostic accuracy and radiation dose of prospective and retrospective electrocardiogram (ECG) gated dual source computed tomography (DSCT) for the evaluation of the coronary stent, using conventional coronary angiography (CA) as a standard reference. Design, setting and patients: Sixty patients (heart rates {<=}70 bpm) with previous stent implantation who were scheduled for CA were divided in two groups, receiving either prospective or retrospective ECG gated DSCT separately. Two reviewers scored coronary stent image quality and evaluated stent lumen. Results: There was no significant difference in image quality between the two groups. In the prospective group, there were 86.4% (51/59) stents with interpretable images, in the retrospective group, there were 87.5% (49/56) stents with interpretable images. Image quality was not influenced by age, body mass index or heart rate in either group, but heart rate variability had a weak impact on the image quality of the prospective group. Image noise was higher in the prospective group, but this difference reached statistical significance only by using a smooth kernel reconstruction. Per-stent based sensitivity, specificity, and positive and negative predictive value were 100%, 84.1%, 68.2%, and 100%, respectively, in the prospective CT angiography group and 94.4%, 86.8%, 77.3%, and 97.1%, respectively, in the retrospective CT angiography group. There was a significant difference in the effective radiation dose between the two groups, mean effective dose in the prospective and retrospective group was 2.2 {+-} 0.5 mSv (1.5-3.2 mSv) and 14.6 {+-} 3.3 mSv (10.0-20.4 mSv) (p < .001) respectively. Conclusions: Compared with retrospective CT angiography, prospective CT angiography has a similar performance in assessing coronary stent patency, but a lower effective dose in selected patients with regular heart rates {<=}70 bpm.

  15. Low-dose adaptive sequential scan for dual-source CT coronary angiography in patients with high heart rate: Comparison with retrospective ECG gating

    Energy Technology Data Exchange (ETDEWEB)

    Xu Lei, E-mail: leixu2001@hotmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Yang Lin, E-mail: anna7949@163.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Zhang Zhaoqi, E-mail: zhaoqi5000@vip.sohu.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Li Yu, E-mail: athen06@hotmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Fan Zhanming, E-mail: fanzm120@tom.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Ma Xiaohai, E-mail: maxi8238@gmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Lv Biao, E-mail: biao_lu2007@sina.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Yu Wei, E-mail: yuwei02@gmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China)

    2010-11-15

    Purpose: To explore feasibility of dual-source CT (DS-CT) prospective ECG-gated coronary angiography in patients with heart rate (HR) higher than 70 beat per minute (bpm), and evaluate image quality and radiation dose with comparison to retrospective ECG-gated spiral scan. Materials and methods: One hundred patients who underwent DS-CT coronary angiography (DS-CTCA) with mean HR higher than 70 bpm but below 110 bpm were enrolled in the study, 50 were scanned by adaptive sequential scan and another 50 were analyzed by retrospectively gated CT scan. The imaging quality of coronary artery segments in the two groups was evaluated using a four-point grading scale by two independent reviewers. Patient radiation dose was calculated by multiplying dose length product by conversion coefficient of 0.017. Results: There was no significant difference between the two groups for mean HR (p = 0.305), HR variability (p = 0.103), body mass index (p = 0.472), and scan length (p = 0.208). There was good agreement for image quality scoring between the two reviewers (Kappa = 0.72). Coronary evaluability of adaptive sequential scan was 99.7% (608 of 610 segments), while that of retrospective gated scan was 98.7% (614 of 622 segments), showing similar coronary evaluability (p = 0.061). Effective doses of adaptive sequential scan and retrospective gated scan were 5.1 {+-} 1.6 and 11.8 {+-} 4.5 mSv, respectively (p < 0.001), showing that adaptive sequential scan reduced radiation dose by 57% compared with that of retrospective gated scan. Conclusions: In patients with 70-110 bpm HR, DS-CTCA adaptive sequential scan shows similar image quality as retrospective ECG-gated spiral scan with 57% reduction of radiation dose.

  16. Image quality and radiation dose of 128-slice dual-source CT venography using low kilovoltage combined with high-pitch scanning and automatic tube current modulation.

    Science.gov (United States)

    Park, Chan Kue; Choo, Ki Seok; Jeon, Ung Bae; Baik, Seung Kug; Kim, Yong Woo; Kim, Tae Un; Kim, Chang Won; Jeong, Yeon Ju; Jeong, Dong Wook; Lim, Soo Jin

    2013-06-01

    To compare vascular enhancement, image quality, and radiation dose of 128-slice dual-source CT venography (CTV) between an imaging setting of 120 kVp with low pitch, and a setting of 100 kVp combined with high pitch and automatic tube current modulation. A total of 100 patients with suspected deep vein thrombosis and varicose veins were divided into two groups: Group 1 [50 patients, 120 kVp, low pitch (0.6), and fixed 120 mA) and Group 2 (50 patients, 100 kVp, high pitch (3.0), and automatic tube current modulation]. Two radiologists, who were blinded to the image protocol, assessed vascular enhancement and image noise in the inferior vena cava (IVC), femoral vein, and popliteal vein. They also assigned an image quality score independently using a 5-point visual scale. Effective dose was estimated using the dose-length product (DLP). Group demographics, radiation dose, vascular enhancement, image noise, and image quality in the two groups were analyzed. Mean vascular enhancement of the IVC, femoral vein, and popliteal vein was significantly higher in group 2 than in group 1, and images in group 2 had significantly higher image noise. However, there were no significant differences in subjective image quality score of the IVC, femoral vein, and popliteal vein. The mean DLP in group 2 (402.10 ± 94.29 mGy cm) was significantly lower than that in group 1 (973.36 ± 63.20 mGy cm) (P enhancement with acceptable image quality and low radiation dose.

  17. Diagnostic Value of 64-Slice Dual-Source CT Coronary Angiography in Patients with Atrial Fibrillation: Comparison with Invasive Coronary Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jian Jun; Liu, Tie; Feng, Yue; Wu, Wei Feng; Mou, Cai Yun; Zhai, Li Hao [Zhejiang Hospital, Hangzhou (China)

    2011-08-15

    We wanted to evaluate the image quality and diagnostic value of 64-slice dual-source computed tomography (DSCT) coronary angiography in patients with atrial fibrillation (Afib). The coronary arteries of 22 Afib patients seen on DSCT were classified into 15 segments and the imaging quality (excellent, good, moderate and poor) and significant stenoses ({>=} 50%) were evaluated by two radiologists who were blinded to the conventional coronary angiography (CAG) results. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for detecting important coronary artery stenosis were calculated. McNemar test was used to determine any significant difference between DSCT and CAG, and Cohen's Kappa statistics were calculated for the intermodality and interobserver agreement. The mean heart rate was 89 {+-} 8.3 bpm (range: 80-118 bpm). A range from 250 msec to 300 msec within the RR interval was the optimal reconstruction interval for the patients with Afib. The respective overall sensitivity, specificity, PPV and NPV values were 74%, 97%, 81% and 96% for reader 1 and 72%, 98%, 85% and 96% for reader 2. No significant difference between DSCT and CAG was found for detecting a significant stenosis (reader 1, p = 1.0; reader 2, p = 0.727). Cohen's Kappa statistics demonstrated good intermodality and interobserver agreement. 64-slice DSCT coronary angiography provides good image quality in patients with atrial fibrillation without the need for controlling the heart rate. DSCT can be used for ruling out significant stenosis in patients with atrial fibrillation with its high NPV for detecting in important stenosis.

  18. Assessment of Double Outlet Right Ventricle Associated with Multiple Malformations in Pediatric Patients Using Retrospective ECG-Gated Dual-Source Computed Tomography.

    Directory of Open Access Journals (Sweden)

    Ke Shi

    Full Text Available To evaluate the feasibility and diagnostic accuracy of retrospective electrocardiographically (ECG-gated dual-source computed tomography (DSCT for the assessment of double outlet right ventricle (DORV and associated multiple malformations in pediatric patients.Forty-seven patients <10 years of age with DORV underwent retrospective ECG-gated DSCT. The location of the ventricular septal defect (VSD, alignment of the two great arteries, and associated malformations were assessed. The feasibility of retrospective ECG-gated DSCT in pediatric patients was assessed, the image quality of DSCT and the agreement of the diagnosis of associated malformations between DSCT and transthoracic echocardiography (TTE were evaluated, the diagnostic accuracies of DSCT and TTE were referred to surgical results, and the effective doses were calculated.Apart from DORV, 109 associated malformations were confirmed postoperatively. There was excellent agreement (κ = 0.90 for the diagnosis of associated malformations between DSCT and TTE. However, DSCT was superior to TTE in demonstrating paracardiac anomalies (sensitivity, coronary artery anomalies: 100% vs. 80.00%, anomalies of great vessels: 100% vs. 88.57%, separate thoracic and abdominal anomalies: 100% vs. 76.92%, respectively. Combined with TTE, DSCT can achieve excellent diagnostic performance in intracardiac anomalies (sensitivity, 91.30% vs. 100%. The mean image quality score was 3.70 ± 0.46 (κ = 0.76. The estimated mean effective dose was < 1 mSv (0.88 ± 0.34 mSv.Retrospective ECG-gated DSCT is a better diagnostic tool than TTE for pediatric patients with complex congenital heart disease such as DORV. Combined with TTE, it may reduce or even obviate the use of invasive cardiac catheterization, and thus expose the patients to a much lower radiation dose.

  19. Application Progress of Dual-source CT and Craniocervical CTA%双源CT头颈部CTA的应用进展

    Institute of Scientific and Technical Information of China (English)

    金欣; 韩淑祯; 张晓光

    2014-01-01

    目前双源CT是当今世界上最先进的CT设备,头颈部CTA作为一种无创性检查方法对头颈动脉血管狭窄及斑块的诊断有重要价值和帮助,其优点为检查时间短、成功率高、费用相对低廉、并发症少、安全无创等,可以作为头颈部动脉血管检查的首选和重要方法。头颈部血管病变是脑血管疾病的主要发病原因之一,尽早发现头颈部动脉病变,通过发现“罪犯血管”进行及时干预治疗和二级预防,可显著降低脑血管疾病的发病率、致残率、死亡率。%Dual-source CT is currently the most advanced CT equipment in the world. Craniocervical CTA as a noninvasive method, has significant value and assistance for the diagnosis of head and neck artery stenosis and plaque, its advantages including short time, high success rate, relatively low cost, fewer complications, safety and noninvasiveness, and can serve as a preferred and important method for head and neck arteries inspection. Craniocervical vascular disease is one of the major causes of cerebrovascular diseases, early detection of head and neck artery disease, finding“culprit vessels”and timely carrying out intervention treatment and secondary prevention, can significantly reduce the incidence of cerebrovascular diseases.

  20. Automated tube voltage selection for radiation dose and contrast medium reduction at coronary CT angiography using 3{sup rd} generation dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Stefanie [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Wichmann, Julian L. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Schoepf, U.J. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Poole, Zachary B.; Varga-Szemes, Akos; De Cecco, Carlo N. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Canstein, Christian [Siemens Medical Solutions, Malvern, PA (United States); Caruso, Damiano [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Bamberg, Fabian; Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2016-10-15

    To investigate the relationship between automated tube voltage selection (ATVS) and body mass index (BMI) and its effect on image quality and radiation dose of coronary CT angiography (CCTA). We evaluated 272 patients who underwent CCTA with 3{sup rd} generation dual-source CT (DSCT). Prospectively ECG-triggered spiral acquisition was performed with automated tube current selection and advanced iterative reconstruction. Tube voltages were selected by ATVS (70-120 kV). BMI, effective dose (ED), and vascular attenuation in the coronary arteries were recorded. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Five-point scales were used for subjective image quality analysis. Image quality was rated good to excellent in 98.9 % of examinations without significant differences for proximal and distal attenuation (all p ≥.0516), whereas image noise was rated significantly higher at 70 kV compared to ≥100 kV (all p <.0266). However, no significant differences were observed in SNR or CNR at 70-120 kV (all p ≥.0829). Mean ED at 70-120 kV was 1.5 ± 1.2 mSv, 2.4 ± 1.5 mSv, 3.6 ± 2.7 mSv, 5.9 ± 4.0 mSv, 7.9 ± 4.2 mSv, and 10.7 ± 4.1 mSv, respectively (all p ≤.0414). Correlation analysis showed a moderate association between tube voltage and BMI (r =.639). ATVS allows individual tube voltage adaptation for CCTA performed with 3{sup rd} generation DSCT, resulting in significantly decreased radiation exposure while maintaining image quality. (orig.)

  1. Effects of adenosine agonist R-phenylisopropyl-adenosine on halothane anesthesia and antinociception in rats

    Institute of Scientific and Technical Information of China (English)

    Hai-chun MA; Yan-fen WANG; Chun-sheng FENG; Hua ZHAO; Shuji DOHI

    2005-01-01

    Aim: To investigate the antinociceptive effect of adenosine agonist Rphenylisopropyl-adenosine (R-PIA) given to conscious rats by intracerebroventricular (ICV) and intrathecal (IT), and identify the effect of R-PIA on minimum alveolar concentration (MAC) of halothane with pretreatment of A1 receptor an tagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) or K+ channel blocker 4-aminopyridine (4-AP). Methods: Sprague-Dawley rats were implanted with 24 gauge stainless steel guide cannula using stereotaxic apparatus and ICV method, and an IT catheter (PE-10, 8.5 cm) was inserted into the lumbar subarachnoid space, while the rats were under pentobarbital anesthesia. After one week of recovery from surgery, rats were randomly assigned to one of the following protocols: MAC of halothane, or tail-flick latency. All measurements were performed after R-PIA (0.8-2.0 μg) microinjection into ICV and IT with or without pretreatment of DPCPX or 4-AP. Results: Microinjection of adenosine agonist R PIA in doses of 0.8-2.0 μg into ICV and IT produced a significant dose- and time dependent antinociceptive action as reflected by increasing latency times and ICV administration of adenosine agonist R-PIA (0.8 μg) reducing halothane anes thetic requirements (by 29%). The antinociception and reducing halothane requirements effected by adenosine agonist R-PIA was abolished by DPCPX and 4-AP. Conclusion: ICV and IT administration of adenosine agonist R-PIA produced an antinociceptive effect in a dose-dependent manner and decreased hal othane MAC with painful stimulation through activation of A1 receptor subtype, and the underlying mechanism involves K+ channel activation.

  2. N6-(2-Hydroxyethyl)-Adenosine Exhibits Insecticidal Activity against Plutella xylostella via Adenosine Receptors

    Science.gov (United States)

    Fang, Ming; Chai, Yiqiu; Chen, Guanjv; Wang, Huidong; Huang, Bo

    2016-01-01

    The diamondback moth, Plutella xylostella, is one of the most important pests of cruciferous crops. We have earlier shown that N6-(2-hydroxyethyl)-adenosine (HEA) exhibits insecticidal activity against P. xylostella. In the present study we investigated the possible mechanism of insecticidal action of HEA on P. xylostella. HEA is a derivative of adenosine, therefore, we speculated whether it acts via P. xylostella adenosine receptor (PxAdoR). We used RNAi approach to silence PxAdoR gene and used antagonist of denosine receptor (AdoR) to study the insecticidal effect of HEA. We cloned the whole sequence of PxAdoR gene. A BLAST search using NCBI protein database showed a 61% identity with the Drosophila adenosine receptor (DmAdoR) and a 32–35% identity with human AdoR. Though the amino acids sequence of PxAdoR was different compared to other adenosine receptors, most of the amino acids that are known to be important for adenosine receptor ligand binding and signaling were present. However, only 30% binding sites key residues was similar between PxAdoR and A1R. HEA, at a dose of 1 mg/mL, was found to be lethal to the second-instar larvae of P. xylostella, and a significant reduction of mortality and growth inhibition ratio were obtained when HEA was administered to the larvae along with PxAdoR-dsRNA or antagonist of AdoR (SCH58261) for 36, 48, or 60 h. Especially at 48 h, the rate of growth inhibition of the PxAdoR knockdown group was 3.5-fold less than that of the HEA group, and the corrected mortality of SCH58261 group was reduced almost 2-fold compared with the HEA group. Our findings show that HEA may exert its insecticidal activity against P. xylostella larvae via acting on PxAdoR. PMID:27668428

  3. N6-(2-Hydroxyethyl)-Adenosine Exhibits Insecticidal Activity against Plutella xylostella via Adenosine Receptors.

    Science.gov (United States)

    Fang, Ming; Chai, Yiqiu; Chen, Guanjv; Wang, Huidong; Huang, Bo

    The diamondback moth, Plutella xylostella, is one of the most important pests of cruciferous crops. We have earlier shown that N6-(2-hydroxyethyl)-adenosine (HEA) exhibits insecticidal activity against P. xylostella. In the present study we investigated the possible mechanism of insecticidal action of HEA on P. xylostella. HEA is a derivative of adenosine, therefore, we speculated whether it acts via P. xylostella adenosine receptor (PxAdoR). We used RNAi approach to silence PxAdoR gene and used antagonist of denosine receptor (AdoR) to study the insecticidal effect of HEA. We cloned the whole sequence of PxAdoR gene. A BLAST search using NCBI protein database showed a 61% identity with the Drosophila adenosine receptor (DmAdoR) and a 32-35% identity with human AdoR. Though the amino acids sequence of PxAdoR was different compared to other adenosine receptors, most of the amino acids that are known to be important for adenosine receptor ligand binding and signaling were present. However, only 30% binding sites key residues was similar between PxAdoR and A1R. HEA, at a dose of 1 mg/mL, was found to be lethal to the second-instar larvae of P. xylostella, and a significant reduction of mortality and growth inhibition ratio were obtained when HEA was administered to the larvae along with PxAdoR-dsRNA or antagonist of AdoR (SCH58261) for 36, 48, or 60 h. Especially at 48 h, the rate of growth inhibition of the PxAdoR knockdown group was 3.5-fold less than that of the HEA group, and the corrected mortality of SCH58261 group was reduced almost 2-fold compared with the HEA group. Our findings show that HEA may exert its insecticidal activity against P. xylostella larvae via acting on PxAdoR.

  4. 46 CFR 129.326 - Dual-voltage generators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Dual-voltage generators. 129.326 Section 129.326... INSTALLATIONS Power Sources and Distribution Systems § 129.326 Dual-voltage generators. If a dual-voltage generator is installed on an OSV— (a) The neutral of the dual-voltage system must be solidly grounded at...

  5. 46 CFR 120.324 - Dual voltage generators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Dual voltage generators. 120.324 Section 120.324... INSTALLATION Power Sources and Distribution Systems § 120.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1) The neutral of a dual...

  6. The Role of Adenosine Signaling in Headache: A Review

    Directory of Open Access Journals (Sweden)

    Nathan T. Fried

    2017-03-01

    Full Text Available Migraine is the third most prevalent disease on the planet, yet our understanding of its mechanisms and pathophysiology is surprisingly incomplete. Recent studies have built upon decades of evidence that adenosine, a purine nucleoside that can act as a neuromodulator, is involved in pain transmission and sensitization. Clinical evidence and rodent studies have suggested that adenosine signaling also plays a critical role in migraine headache. This is further supported by the widespread use of caffeine, an adenosine receptor antagonist, in several headache treatments. In this review, we highlight evidence that supports the involvement of adenosine signaling in different forms of headache, headache triggers, and basic headache physiology. This evidence supports adenosine A2A receptors as a critical adenosine receptor subtype involved in headache pain. Adenosine A2A receptor signaling may contribute to headache via the modulation of intracellular Cyclic adenosine monophosphate (cAMP production or 5' AMP-activated protein kinase (AMPK activity in neurons and glia to affect glutamatergic synaptic transmission within the brainstem. This evidence supports the further study of adenosine signaling in headache and potentially illuminates it as a novel therapeutic target for migraine.

  7. Primary adenosine monophosphate (AMP) deaminase deficiency in a hypotonic infant.

    Science.gov (United States)

    Castro-Gago, Manuel; Gómez-Lado, Carmen; Pérez-Gay, Laura; Eirís-Puñal, Jesús; Martínez, Elena Pintos; García-Consuegra, Inés; Martín, Miguel Angel

    2011-06-01

    The spectrum of the adenosine monophosphate (AMP) deaminase deficiency ranges from asymptomatic carriers to patients who manifest exercise-induced muscle pain, occasionally rhabdomyolysis, and idiopathic hyperCKemia. However, previous to the introduction of molecular techniques, rare cases with congenital weakness and hypotonia have also been reported. We report a 6-month-old girl with the association of congenital muscle weakness and hypotonia, muscle deficiency of adenosine monophosphate deaminase, and the homozygous C to T mutation at nucleotide 34 of the adenosine monophosphate deaminase-1 gene. This observation indicates the possible existence of a primary adenosine monophosphate deaminase deficiency manifested by congenital muscle weakness and hypotonia.

  8. Pretreatment with adenosine and adenosine A1 receptor agonist protects against intestinal ischemia-reperfusion injury in rat

    Institute of Scientific and Technical Information of China (English)

    V Haktan Ozacmak; Hale Sayan

    2007-01-01

    AIM: To examine the effects of adenosine and A1 receptor activation on reperfusion-induced small intestinal injury.METHODS: Rats were randomized into groups with sham operation, ischemia and reperfusion, and systemic treatments with either adenosine or 2-chloro-N6-cyclopentyladenosine, A1 receptor agonist or 8-cyclopentyl-1,3-dipropylxanthine, A1 receptor antagonist, plus adenosine before ischemia. Following reperfusion, contractions of ileum segments in response to KCl, carbachol and substance P were recorded. Tissue myeloperoxidase,malondialdehyde, and reduced glutathione levels were measured.RESULTS: Ischemia significantly decreased both contraction and reduced glutathione level which were ameliorated by adenosine and agonist administration. Treatment also decreased neutrophil infiltration and membrane lipid peroxidation. Beneficial effects of adenosine were abolished by pretreatment with A1 receptor antagonist.CONCLUSION: The data suggest that adenosine and A1 receptor stimulation attenuate ischemic intestinal injury via decreasing oxidative stress, lowering neutrophil infiltration, and increasing reduced glutathione content.

  9. Clinical Value of Dual Source CT in the Diagnosis of Coronary Artery Stenosis%双源CT诊断不同程度冠状动脉狭窄的临床价值

    Institute of Scientific and Technical Information of China (English)

    高振兴; 佟晖

    2015-01-01

    Objective To investigate the clinical value of dual source CT in the diagnosis of coronary artery stenosis.MethodsThirty-six patients with clinicaly suspected coronary heart disease in our hospital received with dual source CT and conventional coronary angiography.Results Dual source CT findings and coronary angiography results were compared and the diagnosis of coronary artery stenosis sensitivity for 94.7%,specificity of diagnosis of 95.5%,the positive predictive value for 83.4%,the negative predictive value was 98.78%. The diagnostic accuracy rate was 95.3%. Dual source CT in the diagnosis of severe stenosis diagnostic sensitivity was significantly lower than that of mild stenosis,moderate stenosis diagnosis sensitivity, he difference had statistical significance(P< 0.05).Conclusion With the traditional coronary artery stenosis diagnosis coronary angiography were compared with and dual source CT scan with rapid scanning,high accuracy in the diagnosis and noninvasive clinical advantage.%目的:探讨双源CT诊断不同程度冠状动脉狭窄的临床价值。方法选取来我院因临床拟诊冠心病而接受双源CT和传统冠状动脉造影检查的患者36例。结果双源CT检查结果与冠状动脉造影检查结果相比,其冠状动脉狭窄诊断的敏感度为94.7%、诊断特异性为95.5%、阳性预测值为83.4%、阴性预测值为98.78%,诊断准确率为95.3%。双源CT检查对重度狭窄诊断敏感度低于轻度狭窄和中度狭窄的诊断敏感度,比较差异具有统计学意义(P<0.05)。结论与传统冠状动脉狭窄诊断方式冠状动脉造影相比,双源CT扫描具有扫描迅速、诊断准确率较高,无创伤等临床优势。

  10. 双源计算机断层扫描在永存动脉干诊断中的应用%Clinical application of dual-source CT in diagnosis of persistent truncus arteriosus

    Institute of Scientific and Technical Information of China (English)

    冯越; 刘铁; 翟利浩

    2012-01-01

    Objectives To explore the clinical values of dual - source computed tomography ( CT) in diagnosis of persistent truncus arteriosus(PTA). Methods Seven patients (aged 7 days to 8 years, middle age 3.4 years) diagnosed as PTA by echocardiography underwent cardiac CT with dual-source CT machine. Two- and three-dimensional images were reformated by multiple planar reformation (coronal, sagital and oblique), maximum intensity projection and volume rendering. Of the 7 patients, 4 underwent angiocardiography. Results Qualitative and classification diagnosis were made through Dual-source CT in all the 7 cases. Dual-source CT visualized 28 concomitant anomalies while echocardiography visualized 24 in all the 7 cases. Conclusions Qualitalive and classification diagnosis can be made through Dual-source CT which contributes to the strategies and improvement of operations.%目的 探讨双源计算机断层扫面(computed tomography,CT)在永存动脉干诊断中的应用价值.方法 选择7例经超声心动图诊断为永存动脉干患者,年龄7d~8岁,中位年龄3.4岁.采用双源CT,心电门控下对比增强完成心脏检查,并在图像工作站完成多平面(MPR)、最大密度投影(MIP)和三维容积漫游(VR)处理.其中有4例进行心导管检查.结果 双源CT对7例永存动脉干均作出定性诊断和分型诊断,共发现合并畸形28处.超声心动图共显示24处.结论 双源CT可以对永存动脉干患者作出准确诊断及分型,并有助于临床手术方案的制订与完善.

  11. New dual-source CT and dual-energy imaging in analysis of compositions of urinary calculi%新双源CT双能量成像对泌尿系结石成分定性诊断的价值

    Institute of Scientific and Technical Information of China (English)

    林黛英; 吴先衡; 汪丹凤; 林少帆; 黄宝泉

    2014-01-01

    目的 探讨新双源CT双能量成像分析泌尿系统结石成分的临床价值.方法 对45例尿路结石患者行双源CT双能量扫描,分析其结石成分,比较体外红外光谱法分析结石成分的结果,分析双源CT分析各种成分泌尿系结石的特异性与敏感性.结果 双源CT能准确区分尿酸结石和非尿酸结石,灵敏度和特异度均为100.00%;磷酸盐结石的诊断灵敏度为93.10%,特异度为92.00%;胱氨酸结石的诊断灵敏度为66.67%,特异度为97.90%;草酸钙结石灵敏度为85.71%,特异度为100.00%.结论 新双源CT双能量成像能在治疗前对泌尿系结石的成分进行分析,对结石的治疗及预防具有重要意义.%Objective To explore the clinical value of new dual-source CT and dual-energy imaging in the analysis of the compositions of urinary calculi.Methods The compositions of urinary calculi in 45 patients were analyzed being scanned with new dual-source CT and dual-energy imaging.The compositions of urinary calculi was compared with the results from infrared spectrometry in vitro.The sensitivity and specificity of the composition of urinary calculi were analyzed with new dual-source CT.Results Dual-source CT could accurately distinguish nonuric acid stones from uric acid calculi,and its sensitivity and specificity were both 100.00%; the diagnosis sensitivity and specificity to phosphate stones were 93.10% and 92.00%; the diagnosis sensitivity and specificity to cystine stones were 66.67% and 97.90%; and the diagnosis sensitivity and specificity to calcium oxalate stones were 85.71% and 100.00%.Conclusions Dual-source CT and dual-energy imaging can analyze the compositions of urinary calculi before treatment and has important significance in preventing and treating calculi.

  12. Mechanism of protection of adenosine from sulphate radical anion and repair of adenosine radicals by caffeic acid in aqueous solution

    Indian Academy of Sciences (India)

    M Sudha Swaraga; L Charitha; M Adinarayana

    2005-07-01

    The photooxidation of adenosine in presence of peroxydisulphate (PDS) has been studied by spectrophotometrically measuring the absorbance of adenosine at 260 nm. The rates of oxidation of adenosine by sulphate radical anion have been determined in the presence of different concentrations of caffeic acid. Increase in [caffeic acid] is found to decrease the rate of oxidation of adenosine suggesting that caffeic acid acts as an efficient scavenger of $SO_{4}^{\\bullet-}$ and protects adenosine from it. Sulphate radical anion competes for adenosine as well as for caffeic acid. The quantum yields of photooxidation of adenosine have been calculated from the rates of oxidation of adenosine and the light intensity absorbed by PDS at 254 nm, the wavelength at which PDS is activated to sulphate radical anion. From the results of experimentally determined quantum yields (exptl) and the quantum yields calculated (cal) assuming caffeic acid acting only as a scavenger of $SO_{4}^{\\bullet-}$ show that exptl values are lower than cal values. The ' values, which are experimentally found quantum yield values at each caffeic acid concentration and corrected for $SO_{4}^{\\bullet-}$ scavenging by caffeic acid, are also found to be greater than exptl values. These observations suggest that the transient adenosine radicals are repaired by caffeic acid in addition to scavenging of sulphate radical anions.

  13. Electroacupuncture improves neuropathic pain Adenosine,adenosine 5'-triphosphate disodium and their receptors perhaps change simultaneously

    Institute of Scientific and Technical Information of China (English)

    Wen Ren; Wenzhan Tu; Songhe Jiang; Ruidong Cheng; Yaping Du

    2012-01-01

    Applying a stimulating current to acupoints through acupuncture needles-known as electroacupuncture-has the potential to produce analgesic effects in human subjects and experimental animals.When acupuncture was applied in a rat model,adenosine 5'-triphosphate disodium in the extracellular space was broken down into adenosine,which in turn inhibited pain transmission by means of an adenosine A1 receptor-dependent process.Direct injection of an adenosine A1 receptor agonist enhanced the analgesic effect of acupuncture.The analgesic effect of acupuncture appears to be mediated by activation of A1 receptors located on ascending nerves.In neuropathic pain,there is upregulation of P2X purinoceptor 3(P2X3)receptor expression in dorsal root ganglion neurons.Conversely,the onset of mechanical hyperalgesia was diminished and established hyperalgesia was significantly reversed when P2X3 receptor expression was downregulated.The pathways upon which electroacupuncture appear to act are interwoven with pain pathways,and electroacupuncture stimuli converge with impulses originating from painful areas.Electroacupuncture may act via purinergic A1 and P2X3 receptors simultaneously to induce an analgesic effect on neuropathic pain.

  14. sources

    Directory of Open Access Journals (Sweden)

    Shu-Yin Chiang

    2002-01-01

    Full Text Available In this paper, we study the simplified models of the ATM (Asynchronous Transfer Mode multiplexer network with Bernoulli random traffic sources. Based on the model, the performance measures are analyzed by the different output service schemes.

  15. Diagnostic accuracy and its affecting factors of dual-source CT for assessment of coronary stents patency and in-stent restenosis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xing-hua; YANG Li; WU Jian; JU Hai-yue; ZHANG Fan; HE Bin; CHEN Yun-dai

    2012-01-01

    Background In-stent restenosis is a common complication after stent implantation.However,the assessment of stent lumen in computed tomography (CT) coronary angiography is limited by multiple factors.Our study aimed to evaluate the accuracy and the suspected affecting factors in diagnosing coronary in-stent restenosis by dual-source CT (DSCT) compared with coronary angiography.Methods One hundred and fifteen stents in 50 patients were evaluated with DSCT before coronary angiography for the detection of coronary in-stent restenosis (≥ 50% luminal narrowing).Patency of each stent was analyzed by two independent expert radiologists blinded to the results of coronary angiography.The relationship between diagnostic accuracy and the suspected factors including age,body mass index (BMI),heart rate,variation of heart rate,radiation dose,image quality,location and stent characteristics (type,material,diameter,length and strut thickness) was assessed wilh both univariate and multivariate analysis.The fitting of a Logistic regression model was evaluated using a receiver operating characteristic (ROC) curve.Results Mean stent diameter was (2.9±0.4) mm.Sensitivity,specificity,positive and negative predictive values and accuracy of DSCT in detection of in-stent restenosis were 69.2%,91.2%,50.0%,95.9%,and 88.7%,respectively.In a subgroup of stents with a diameter ≥3.0 mm,sensitivity,specificity,positive and negative predictive values and accuracy were 100.0%,96.5%,75.0%,100.0%+ and 96.8%,respectively.Stent diameter <3.0 mm and poor image quality were associated with poor diagnostic accuracy (P <0.05).The area under curve of ROC was 0.79.Conclusion DSCT can provide high accuracy for the assessment of in-stent restenosis in stents with a diameter ≥3.0mm,and can play an important role in ruling out in-stent restenosis.

  16. Intravenous Contrast Material Administration at High-pitch Dual-source CT Coronary Angiography: Bolus-tracking Technique with Shortened Time of Respiratory Instruction Versus Test Bolus Technique

    Institute of Scientific and Technical Information of China (English)

    Kai Sun; Guo-rong Liu; Yue-chun Li; Rui-juan Han; Li-fang Cui; Li-jun Ma; Li-gang Li; Chang-yong Li

    2012-01-01

    Objective To investigate the feasibility of acquiring the similar homogeneous enhancement using bolus-tracking techniques with shortened respiratory time in prospectively electrocardiogram-gated high-pitch spiral acquisition mode (Flash mode) coronary computed tomography angiography (CCTA) compared with test bolus technique.Methods One hundred and eighty-four consecutive patients with mean heart rate ≤65 beats per minute undergoing CCTA were prospectively included in this study.The patients were randomly divided into two groups.Patients in the group A (n=92) instructed to shorten respiratory time received CCTA using bolus-tracking technique with high-pitch spiral acquisition mode (Flash mode),while those in the group B (n=92) underwent CCTA with test bolus technique.The attenuation in the ascending aorta,image noise,contrast-to-noise ratio and radiation doses of the two groups were assessed.Results There were no significant differences in the mean attenuation values in the ascending aorta (483.18±59.07 HU vs.498.7±83.51 HU,P=0.183),image noise (21.4±4.5 HU vs.20.9±4.3 HU,P=0.414),contrast-to-noise ratio (12.1±4.2 vs.13.8±5.1,P=0.31) between the groups A and B.There were no significant differences in the radiation dose of dynamic monitoring scans (0.056±0.026 mSv vs.0.062±0.018 mSv,P=0.068) and radiation dose of angiography (0.94±0.07 mSv vs.0.96±0.15 mSv,P=0.926) between the two groups,while 15 mL less contrast material volume was administered in the group A than the group B.Conclusion Bolus-tracking technique with shortened time of respiratory in Flash mode of dual-source CT yields the similar homogeneous enhancement with less contrast material in comparison to the test bolus technique.

  17. Radiation dose for thoracic and coronary step-and-shoot CT using a 128-slice dual-source machine in infants and small children with congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Jean-Francois; Rohnean, Adela; Elfassy, Eric; Sigal-Cinqualbre, Anne [Radiology-Centre Chirurgical Marie Lannelongue, Plessis-Robinson (France)

    2011-02-15

    For coronary artery visualization, retrospective ECG-gated acquisition by dual-source computed tomography (DSCT) was superior to spiral non-ECG-gated acquisition in a paediatric population of congenital heart disease (CHD) patients. However, retrospective cardiac CT is associated with substantial radiation doses to the patient. Recently, DSCT with end-systolic reconstruction was found to be robust for imaging the coronary arteries in patients with high heart rates. To evaluate step-and-shoot DSCT with end-systolic reconstruction for evaluating the heart, coronary arteries and other thoracic structures in young children with CHD. All neonates and children younger than 6 years of age who were referred to our institution for CHD evaluation between September and October 2009 were included in the study. ECG-gated DSCT was performed in sequential prospective mode centred on the systolic phase identified by ECG analysis. To assess the radiation dose, we recorded the dose-length product (DLP) in mGy.cm and the effective dose in mSv estimated from the DLP. Overall image quality was evaluated using a 5-grade scoring system and was assessed by looking at cardiac and vascular structures. The image quality for the proximal and middle segments of the right and left coronary arteries was also evaluated using a 5-grade scale. Images of diagnostic quality (grade {>=} 3) were obtained in all 30 children with a mean image quality grade of 4.7 {+-} 0.6 (range, 3-5). Mean DLP was 5.7 {+-} 4.8 mGy*cm (range, 1-22 mGy cm) and mean effective radiation dose was 0.26 {+-} 0.16 mSv (range, 0.05-0.8 mSv). Prospective ECG-gated thoracic DSCT at end-systole usually provides adequate thoracic and coronary artery image quality in neonates, infants and young children with CHD, independent of heart rate. This new method is associated with lower radiation doses compared to previous literature (mean effective dose, 0.26 mSv). (orig.)

  18. Triple-rule-out dual-source CT angiography of patients with acute chest pain: Dose reduction potential of 100 kV scanning

    Energy Technology Data Exchange (ETDEWEB)

    Krissak, Radko, E-mail: radko.krissak@umm.de [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Henzler, Thomas; Prechel, Anne; Reichert, Miriam [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Gruettner, Joachim; Sueselbeck, Tim [1st Department of Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Schoenberg, Stefan O.; Fink, Christian [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany)

    2012-12-15

    Purpose: To investigate the dose reduction potential of low kV triple-rule-out dual-source CT angiography (TRO-CTA) in non-obese (BMI ≤ 25 kg/m{sup 2}) patients with acute chest pain. Materials and methods: Sixty consecutive patients were randomly assigned to two different retrospectively ECG-gated TRO-CTA protocols in this prospective trial: Thirty patients were examined with a 120-kV standard protocol (320 reference mAs with automatic tube current modulation, automatically adapted pitch and ECG-pulsing) and served as the control group (group 1), an otherwise identical 100 kV protocol was used in the other thirty patients (group 2) for a radiation dose reduction. Subjective image quality was assessed on a 5 point scale (1: excellent, 5: non-diagnostic) by two blinded observers. Quantitative image analysis assessed vascular attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in different vascular segments. The effective dose was calculated from the dose length product (DLP) using a conversion coefficient of 0.017 mSv mGy{sup −1} cm{sup −1}. Results: There was no significant difference of age, BMI, heart rate, pitch or scan length between both patient groups. Subjective image quality was rated similar in both groups (group 1: 1.2 ± 0.4, group 2: average score = 1.3 ± 0.5). Vessel attenuation was significantly higher in group 2 than in group 1 (ascending aorta: 456 ± 83 HU vs. 370 ± 78 HU, p < 0.001; pulmonary artery: 468 ± 118 HU vs. 411 ± 91 HU, p = 0.03; left coronary artery: 437 ± 110 HU vs. 348 ± 89 HU, p < 0.001), however, there was no significant difference in SNR (13.2 ± 7.6 vs. 14.5 ± 7.5, p = 0.49) or CNR (13.8 ± 6.6 vs. 15.9 ± 7.7, p = 0.25). The effective radiation dose of the 100 kV protocol was significantly lower (9.6 ± 3.2 mSv vs. 18.1 ± 9.4 mSv, p < 0.0001). Conclusion: TRO-CTA with 100 kV is feasible in non-obese patients and results in diagnostic image quality and significantly reduced radiation dose.

  19. Accuracy of dual-source CT coronary angiography: first experience in a high pre-test probability population without heart rate control

    Energy Technology Data Exchange (ETDEWEB)

    Scheffel, Hans; Alkadhi, Hatem; Desbiolles, Lotus; Frauenfelder, Thomas; Schertler, Thomas; Husmann, Lars; Marincek, Borut; Leschka, Sebastian [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Plass, Andre; Vachenauer, Robert; Grunenfelder, Juerg; Genoni, Michele [Clinic for Cardiovascular Surgery, Zurich (Switzerland); Gaemperli, Oliver; Schepis, Tiziano [University Hospital Zurich, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiovascular Center, Zurich (Switzerland); University of Zurich, Center for Integrative Human Physiology, Zurich (Switzerland)

    2006-12-15

    The aim of this study was to assess the diagnostic accuracy of dual-source computed tomography (DSCT) for evaluation of coronary artery disease (CAD) in a population with extensive coronary calcifications without heart rate control. Thirty patients (24 male, 6 female, mean age 63.1{+-}11.3 years) with a high pre-test probability of CAD underwent DSCT coronary angiography and invasive coronary angiography (ICA) within 14{+-}9 days. No beta-blockers were administered prior to the scan. Two readers independently assessed image quality of all coronary segments with a diameter {>=}1.5 mm using a four-point score (1: excellent to 4: not assessable) and qualitatively assessed significant stenoses as narrowing of the luminal diameter >50%. Causes of false-positive (FP) and false-negative (FN) ratings were assigned to calcifications or motion artifacts. ICA was considered the standard of reference. Mean body mass index was 28.3{+-}3.9 kg/m{sup 2} (range 22.4-36.3 kg/m{sup 2}), mean heart rate during CT was 70.3{+-}14.2 bpm (range 47-102 bpm), and mean Agatston score was 821{+-}904 (range 0-3,110). Image quality was diagnostic (scores 1-3) in 98.6% (414/420) of segments (mean image quality score 1.68{+-}0.75); six segments in three patients were considered not assessable (1.4%). DSCT correctly identified 54 of 56 significant coronary stenoses. Severe calcifications accounted for false ratings in nine segments (eight FP/one FN) and motion artifacts in two segments (one FP/one FN). Overall sensitivity, specificity, positive and negative predictive value for evaluating CAD were 96.4, 97.5, 85.7, and 99.4%, respectively. First experience indicates that DSCT coronary angiography provides high diagnostic accuracy for assessment of CAD in a high pre-test probability population with extensive coronary calcifications and without heart rate control. (orig.)

  20. Comorbidities in Neurology: Is Adenosine the Common Link?

    Science.gov (United States)

    Boison, Detlev; Aronica, Eleonora

    2015-01-01

    Comorbidities in Neurology represent a major conceptual and therapeutic challenge. For example, temporal lobe epilepsy (TLE) is a syndrome comprised of epileptic seizures and comorbid symptoms including memory and psychiatric impairment, depression, and sleep dysfunction. Similarly, Alzheimer’s disease (AD), Parkinson’s disease (PD), and Amyotrophic Lateral Sclerosis (ALS) are accompanied by various degrees of memory dysfunction. Patients with AD have an increased likelihood for seizures, whereas all four conditions share certain aspects of psychosis, depression, and sleep dysfunction. This remarkable overlap suggests common pathophysiological mechanisms, which include synaptic dysfunction and synaptotoxicity, as well as glial activation and astrogliosis. Astrogliosis is linked to synapse function via the tripartite synapse, but astrocytes also control the availability of gliotransmitters and adenosine. Here we will specifically focus on the ‘adenosine hypothesis of comorbidities’ implying that astrocyte activation, via overexpression of adenosine kinase (ADK), induces a deficiency in the homeostatic tone of adenosine. We present evidence from patient-derived samples showing astrogliosis and overexpression of ADK as common pathological hallmark of epilepsy, AD, PD, and ALS. We discuss a transgenic ‘comorbidity model’, in which brain-wide overexpression of ADK and resulting adenosine deficiency produces a comorbid spectrum of seizures, altered dopaminergic function, attentional impairment, and deficits in cognitive domains and sleep regulation. We conclude that dysfunction of adenosine signaling is common in neurological conditions, that adenosine dysfunction can explain comorbid phenotypes, and that therapeutic adenosine augmentation might be effective for the treatment of comorbid symptoms in multiple neurological conditions. PMID:25979489

  1. Endogenous adenosine curtails lipopolysaccharide-stimulated tumour necrosis factor synthesis

    NARCIS (Netherlands)

    Eigler, A; Greten, T F; Sinha, B; Haslberger, C; Sullivan, G W; Endres, S

    1997-01-01

    Recent studies have demonstrated the inhibitory effect of exogenous adenosine on TNF production. During inflammation endogenous adenosine levels are elevated and may be one of several anti-inflammatory mediators that reduce TNF synthesis. In the present study the authors investigated this role of ad

  2. Adenosine Receptors: Expression, Function and Regulation

    Directory of Open Access Journals (Sweden)

    Sandeep Sheth

    2014-01-01

    Full Text Available Adenosine receptors (ARs comprise a group of G protein-coupled receptors (GPCR which mediate the physiological actions of adenosine. To date, four AR subtypes have been cloned and identified in different tissues. These receptors have distinct localization, signal transduction pathways and different means of regulation upon exposure to agonists. This review will describe the biochemical characteristics and signaling cascade associated with each receptor and provide insight into how these receptors are regulated in response to agonists. A key property of some of these receptors is their ability to serve as sensors of cellular oxidative stress, which is transmitted by transcription factors, such as nuclear factor (NF-κB, to regulate the expression of ARs. Recent observations of oligomerization of these receptors into homo- and heterodimers will be discussed. In addition, the importance of these receptors in the regulation of normal and pathological processes such as sleep, the development of cancers and in protection against hearing loss will be examined.

  3. Assessment of Acute Chest Pain with Dual-Source CT%双源CT对急性胸痛的诊断价值

    Institute of Scientific and Technical Information of China (English)

    李宇; 范占明; 余婧; 耿冀; 叶红; 晏子旭; 张兆琪

    2011-01-01

    Objective To assess the accuracy of triple rule out protocol for acute chest pain with dual-source CT in emergency department. Methods 56 consecutive patients with acute chest pain were examined with triple rule out protocol on a dual-source scanner (Siemens) at a temporal resolution of 83 ms using a body-mass-adapted contrast material injection. The scanning range included the whole chest from the first ribs to the diaphragm. The level of the carina was defined as the trigger point where the second tube was switched on additionally. The tri-phase injection protocol was used to get enough enhancement of coronary arteries,pulmonary arteries and aortas. One patient was excluded because he was unable to hold breath during scanning. The remaining subjects underwent more than 30 days follow-up. Results All examinations showed an adequate contrast enhancement of the pulmonary arteries, coronary arteries and aortas. The mean volume of contrast medium was (88±5 ) ml. The median radiation exposure was 11.6 mSy (95 %CI 6.9-13.1 ). 14 patients showed coronary arteries atherosclerosis, including coronary arterial stenosis more than 50% in 13 and 12 patients underwent the coronary stent implantation. 11 patients suffered from aortic dissection(Stanford type A), and 11 patients with pulmonary embolism (PE). In brief, the reasons of the chest pain were complex. 7 of the patients suffered from several kinds of chest diseases. The sensitivity and specificity in diagnosing acute chest pain were 98% and 96% ,respectively with CTA. There were no adverse outcomes follow-up for 30 days in this group. Conclusion Triple rule out coronary CT angiography in evaluation of the patients with acute chest pain presented to the emergency department is very helpful, safety and effective way.%目的 评价双源CT胸痛三联扫描计划对急诊胸痛诊断的准确性.方法 按照入选标准连续选取急性胸痛患者56例,采用西门子双源CT扫描仪胸痛三联扫描计划

  4. Neural Correlates of Confidence during Item Recognition and Source Memory Retrieval: Evidence for Both Dual-Process and Strength Memory Theories

    Science.gov (United States)

    Hayes, Scott M.; Buchler, Norbou; Stokes, Jared; Kragel, James; Cabeza, Roberto

    2011-01-01

    Although the medial-temporal lobes (MTL), PFC, and parietal cortex are considered primary nodes in the episodic memory network, there is much debate regarding the contributions of MTL, PFC, and parietal subregions to recollection versus familiarity (dual-process theory) and the feasibility of accounts on the basis of a single memory strength…

  5. System Design as a Three-Phase Dual-Loop (TPDL) Process: Types of Knowledge-Applied Sources of Feedback, and Student Development as Independent Learners

    Science.gov (United States)

    Barak, Moshe

    2010-01-01

    This study aimed at exploring how high school students deal with designing an information system, for example, for a small business or a medical clinic, the extent to which students develop as independent learners while working on their projects, and the factors that help or hinder fostering students' design skills. The three-phase dual-loop…

  6. 单次对比增强双源双能量CT血管成像评估颅内出血及其原因%Evaluation of intracranial hemorrhage and its causes by single-contrast-enhanced dual-source dual-energy CT angiography

    Institute of Scientific and Technical Information of China (English)

    柴学; 张龙江; 盛会雪; 金征宇; 张兆琪; 卢光明

    2012-01-01

    目的 随着双源CT在临床的推广应用,双源CT双能量成像已成为研究热点.文中探讨单次对比增强的双源双能量CT血管血管成像 (CT angiography,CTA)对评估颅内出血及其原因的应用价值.方法对43例蛛网膜下腔出血患者进行双源CT头颅常规平扫(conventional nonenhanced CT,CNCT)及对比增强双能量CT扫描(80kV/400mA和140kV/95mA).利用Liver VNC软件进行对比增强双能量CT数据处理得到虚拟平扫(virtual nonenhanced CT,VNCT)数据,与CNCT检出的蛛网膜下腔出血比较,分析CNCT和VNCT的图像质量、辐射剂量、平均CT值、信噪比、对比噪声比及病灶检出率的差异.利用双能量CTA判断颅内血管异常,并与数字减影血管造影(digital subtraction angiography,DSA)所检出的病变比较诊断符合率.结果 双能量VNCT的图像质量低于常规平扫(Z值=-6.576,P<0.01),但可满足临床诊断要求.VNCT的正常脑组织及出血区CT值、信号噪声比(signal-to-noise ratio,SNR)及对比噪声比(contrast-to-noise ratio,CNR)低于CNCT(P<0.01).VNCT和CNCT对病灶的检出结果 相似.在43例临床疑有脑血管病变的患者中,双能量CTA检出25例患者为动脉瘤,4例为动静脉畸形,3例为烟雾病,11例为阴性,与DSA或手术证实结果 完全一致.双能量CTA患者接受的辐射剂量明显低于常规DSA(P<0.01).结论 从双源双能量CT中获得VNCT平扫图像可用于诊断颅内出血,图像质量可满足临床诊断需要.双能量CTA与DSA的诊断符合率很高.应用该技术可减少每次平扫所接受的辐射剂量,具有潜在的临床应用价值.%Objective Dual-source dual-energy CT imaging is becoming a focus of research with its wide clinical application . This study aimed to investigate intracranial hemorrhage and its causes by single contrast-enhanced dual-source dual-energy CT angiography (CTA). Methods Forty-three patients suspected of subarachnoid hemorrhage underwent head conventional

  7. A High-Affinity Adenosine Kinase from Anopheles Gambiae

    Energy Technology Data Exchange (ETDEWEB)

    M Cassera; M Ho; E Merino; E Burgos; A Rinaldo-Matthis; S Almo; V Schramm

    2011-12-31

    Genome analysis revealed a mosquito orthologue of adenosine kinase in Anopheles gambiae (AgAK; the most important vector for the transmission of Plasmodium falciparum in Africa). P. falciparum are purine auxotrophs and do not express an adenosine kinase but rely on their hosts for purines. AgAK was kinetically characterized and found to have the highest affinity for adenosine (K{sub m} = 8.1 nM) of any known adenosine kinase. AgAK is specific for adenosine at the nucleoside site, but several nucleotide triphosphate phosphoryl donors are tolerated. The AgAK crystal structure with a bound bisubstrate analogue Ap{sub 4}A (2.0 {angstrom} resolution) reveals interactions for adenosine and ATP and the geometry for phosphoryl transfer. The polyphosphate charge is partly neutralized by a bound Mg{sup 2+} ion and an ion pair to a catalytic site Arg. The AgAK structure consists of a large catalytic core in a three-layer {alpha}/{beta}/{alpha} sandwich, and a small cap domain in contact with adenosine. The specificity and tight binding for adenosine arise from hydrogen bond interactions of Asn14, Leu16, Leu40, Leu133, Leu168, Phe168, and Thr171 and the backbone of Ile39 and Phe168 with the adenine ring as well as through hydrogen bond interactions between Asp18, Gly64, and Asn68 and the ribosyl 2'- and 3'-hydroxyl groups. The structure is more similar to that of human adenosine kinase (48% identical) than to that of AK from Toxoplasma gondii (31% identical). With this extraordinary affinity for AgAK, adenosine is efficiently captured and converted to AMP at near the diffusion limit, suggesting an important role for this enzyme in the maintenance of the adenine nucleotide pool. mRNA analysis verifies that AgAK transcripts are produced in the adult insects.

  8. Dual diagnosis

    OpenAIRE

    2013-01-01

    Dual diagnosis denotes intertwining of intellectual disabilities with mental disorders. With the help of systematic examination of literature, intellectual disabilities are determined (they are characterized by subaverage intellectual activity and difficulties in adaptive skills), along side mental disorders. Their influence is seen in changes of thinking, perception, emotionality, behaviour and cognition. Mental disorders often occur with people with intellectual disabilities (data differs f...

  9. 双源 CT 在诊断右室双出口中的应用%Application of dual source CT in the diagnosis of double outlet right ventricle

    Institute of Scientific and Technical Information of China (English)

    吴健; 马延贺; 张洪

    2015-01-01

    Objective:To investigate the value of dual source CT in the diagnosis of double outlet right ventricle (DORV)and anatomic deformities of complex congenital heart disease.Methods:The clinical materials of 17 patients with double outlet right ventricle diagnosed by dual source CT and confirmed by angiocardiography or surgery were analyzed ret-rospectively.The relationship between visceral and atrium,atrium ventricle connection,ventricular vascular connection based on the section analysis were studied.The DORV were classified and the anatomic deformities were identified,which were compared with echocardiography findings.Results:All of the 17 cases of DORV were all diagnosed by dual source CT accu-rately,while only 14 cases were accurately diagnosed by echocardiography.17 cases were classified by dual source CT and echocardiography as subaotic type (10 cases and 8 cases respectively),subpulmonary type (4 cases and 3 cases respective-ly),subpulmonary and subaortic type (one case and one case respectively),abnormality distal to great arteries (2 cases and 2 cases respectively).47 concomitant anatomic deformities of 15 kinds were diagnosed by dual source CT and only 2 were missed with atrial septal defect and patent ductus arteriosus for one case each.Treatment of 11 patients included surgical operation or trans-catheter closure via cardioangiography.Conclusion:Accurate diagnosis and classification of DORV could be obtained by dual source CT,which can provid important guidance for surgical treatment.%目的:探讨双源 CT 对右室双出口(DORV)的诊断价值及对复杂先心病解剖畸形的确诊价值。方法:回顾性分析17例经双源 CT 诊断并经心血管造影、手术等确认为右室双出口的病例资料。通过节段分析法分析内脏-心房关系、心房-心室连接、心室-大血管连接等内容,对 DORV 进行分型并确定解剖畸形,并与超声心动图进行对比。结果:17例DORV 均经双源 CT 正

  10. Measurement of opening and closing angles of aortic valve prostheses in vivo using dual-source computed tomography: Comparison with those of manufacturers' in 10 different types

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Young Joo; Kim, Young Jin; Hong, Yoo Jin; Lee, Hye Jeong; Hur, Jin; Im, Dong Jin; Kim, Yun Jung; Choi, Byoung Wook [Dept. of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2015-10-15

    The aims of this study were to compare opening and closing angles of normally functioning mechanical aortic valves measured on dual-source computed tomography (CT) with the manufacturers' values and to compare CT-measured opening angles according to valve function. A total of 140 patients with 10 different types of mechanical aortic valves, who underwent dual-source cardiac CT, were included. Opening and closing angles were measured on CT images. Agreement between angles in normally functioning valves and the manufacturer values was assessed using the interclass coefficient and the Bland-Altman method. CT-measured opening angles were compared between normal functioning valves and suspected dysfunctioning valves. The CT-measured opening angles of normally functioning valves and manufacturers' values showed excellent agreement for seven valve types (intraclass coefficient [ICC], 0.977; 95% confidence interval [CI], 0.962-0.987). The mean differences in opening angles between the CT measurements and the manufacturers' values were 1.2° in seven types of valves, 11.0° in On-X valves, and 15.5° in ATS valves. The manufacturers' closing angles and those measured by CT showed excellent agreement for all valve types (ICC, 0.953; 95% CI, 0.920-0.972). Among valves with suspected dysfunction, those with limitation of motion (LOM) and an increased pressure gradient (PG) had smaller opening angles than those with LOM only (p < 0.05). Dual-source cardiac CT accurately measures opening and closing angles in most types of mechanical aortic valves, compared with the manufacturers' values. Opening angles on CT differ according to the type of valve dysfunction and a decreased opening angle may suggest an elevated PG.

  11. 双源CT增强扫描检查对肠梗阻患者梗阻部位和梗阻病因的诊断意义%Diagnostic Value of Dual Source CT Enhanced Scan of Intestinal Obstruction

    Institute of Scientific and Technical Information of China (English)

    易琳; 芮军; 相运勇; 袁鑫鑫

    2016-01-01

    Objective To analyze the obstruction site,etiology,diagnosis by dual source CT scan significance. Methods From January 2015 to January 2016 in our hospital to receive treatment for intestinal obstruction in 32 patients for the study,patients admit ed to hospital,administering dual-source CT enhanced scan,clinical data,the inspection process,the diagnosis of patients,etc. were retrospel tively and analyzed. Results The di-agnosis of obstruction,the dual-source CT scan diagnosis entirely consistent with fiber endoscopy findings and surgical results,the site of obstruction diagnosed as 100%in the diagnosis of obstructive reasons,only one case was misdiagnosed as Crohn's disease intestinal tuberculosis,other reasons are consistent with the results of fiber endoscopy and surgical results,cause of obstruction diagnosis was 96. 9%. Conclusion The dual-source CT applied to the site of obstruction and to diagnose the cause can improve the diagnosis rate,to provide a reliable reference for the development of clinical programs.%目的:分析在肠梗阻部位、病因诊断中应用双源CT增强扫描的意义。方法选择2015年1月至2016年1月接收治疗的肠梗阻患者32例为研究对象,患者入院时,施予双源CT增强扫描检查,对患者临床资料、检查过程、诊断结果等进行回顾性分析。结果在梗阻部位的诊断中,双源CT增强扫描诊断结果与纤维镜检查结果和手术结果完全一致,梗阻部位确诊率为100.0%,在梗阻原因的诊断中,仅有1例克罗恩病被误诊为肠结核,其他原因均与纤维镜检查结果和手术结果一致,梗阻原因确诊率为96.9%。结论将双源CT应用到肠梗阻部位及原因的诊断中可提高确诊率,为临床治疗方案的制定提供可靠参考。

  12. Thiamine diphosphate adenylyl transferase from E. coli: functional characterization of the enzyme synthesizing adenosine thiamine triphosphate

    OpenAIRE

    Brans Alain; Makarchikov Alexander F; Bettendorff Lucien

    2007-01-01

    Abstract Background We have recently identified a new thiamine derivative, adenosine thiamine triphosphate (AThTP), in E. coli. In intact bacteria, this nucleotide is synthesized only in the absence of a metabolizable carbon source and quickly disappears as soon as the cells receive a carbon source such as glucose. Thus, we hypothesized that AThTP may be a signal produced in response to carbon starvation. Results Here we show that, in bacterial extracts, the biosynthesis of AThTP is carried o...

  13. 双源CT双能量肺动脉血管成像技术早期诊断肺动脉栓塞患者的实效性评价%The Effectiveness of Dual-source Dual-energy CT Pulmonary Angiography of the Early Diagnosis of Patients with Pulmonary Embolism

    Institute of Scientific and Technical Information of China (English)

    李卫星; 姚菁菁

    2015-01-01

    Objective To investigate the effectiveness of dual-source dual-energy CT pulmonary angiography of the early diagnosis of patients with pulmonary embolism. Methods 40 patients with suspicious pulmonary disease were chosen in our hospital to receive treatment. All patients are dual-source dual-energy CT scan lung machine, with dual-energy scan data evaluation software were analyzed and the lungs into upper, middle and lower, the energy imaging were analyzed. MPR, MIP, VR, CTVE technology to reconstruct the original data were used. Results In 40 patients, 18 patients were diagnosed with pulmonary embolism, pneumonia in 4 patients, 3 patients with lung cancer, 15 patients with normal. 18 cases of patients with pulmonary embolism, a total of 218 emboli, which of central emboli 90, eccentric 46, mural-type 42, type 40 totally were occluded. 15 normal patients, their lung tissue perfusion were analyzed, the upper lungs and lungs, middle and lower comparative analysis, the difference was not statistically significant (t= 1.149,1.021,1.027,1.135, P> 0.05). The normal lung tissue perfusion and pulmonary embolism were analyzed, the upper lungs and lungs, middle and lower comparative analysis, the difference was not statistically significant (t = 6.394,6.092,6.607,6.862, P <0.05). Conclusion Dual-source dual-energy CT pulmonary angiography for the diagnosis of pulmonary embolism in patients has a very important sense and the ability to detect the disease at an early stage of pulmonary embolism, so it is worthy of promotion.%目的:探讨双源CT双能量肺动脉血管成像技术早期诊断肺动脉栓塞患者的实效性评价,为临床提供参考。方法选择我院2013年1月至2014年3月收治的40例可疑肺栓塞疾病患者,所有患者均以双源CT机进行肺部双能量扫描,扫描数据以双能量的评估软件分析,肺部分成上、中、下,进行能量成像分析。采用MPR、MIP、VR、CTVE技术对原始数据进行重建。结果40

  14. Temporal variations of adenosine metabolism in human blood.

    Science.gov (United States)

    Chagoya de Sánchez, V; Hernández-Muñoz, R; Suárez, J; Vidrio, S; Yáñez, L; Aguilar-Roblero, R; Oksenberg, A; Vega-González, A; Villalobos, L; Rosenthal, L; Fernández-Cancino, F; Drucker-Colín, R; Díaz-Muñoz, M

    1996-08-01

    Eight diurnally active (06:00-23:00 h) subjects were adapted for 2 days to the room conditions where the experiments were performed. Blood sampling for adenosine metabolites and metabolizing enzymes was done hourly during the activity span and every 30 min during sleep. The results showed that adenosine and its catabolites (inosine, hypoxanthine, and uric acid), adenosine synthesizing (S-adenosylhomocysteine hydrolase and 5'-nucleotidase), degrading (adenosine deaminase) and nucleotide-forming (adenosine kinase) enzymes as well as adenine nucleotides (AMP, ADP, and ATP) undergo statistically significant fluctuations (ANOVA) during the 24 h. However, energy charge was invariable. Glucose and lactate chronograms were determined as metabolic indicators. The same data analyzed by the chi-square periodogram and Fourier series indicated ultradian oscillatory periods for all the metabolites and enzymatic activities determined, and 24-h oscillatory components for inosine, hypoxanthine, adenine nucleotides, glucose, and the activities of SAH-hydrolase, 5'-nucleotidase, and adenosine kinase. The single cosinor method showed significant oscillatory components exclusively for lactate. As a whole, these results suggest that adenosine metabolism may play a role as a biological oscillator coordinating and/or modulating the energy homeostasis and physiological status of erythrocytes in vivo and could be an important factor in the distribution of purine rings for the rest of the organism.

  15. Vasoconstrictor and vasodilator effects of adenosine in the kidney

    DEFF Research Database (Denmark)

    Hansen, Pernille B; Schnermann, Jurgen

    2003-01-01

    Adenosine is an ATP breakdown product that in most vessels causes vasodilatation and that contributes to the metabolic control of organ perfusion, i.e., to the match between oxygen demand and oxygen delivery. In the renal vasculature, in contrast, adenosine can produce vasoconstriction, a respons...... activation from changes in vascular adenosine concentration, a characteristic that is ideally suited for the role of renal adenosine as a paracrine factor in the control of glomerular function.......Adenosine is an ATP breakdown product that in most vessels causes vasodilatation and that contributes to the metabolic control of organ perfusion, i.e., to the match between oxygen demand and oxygen delivery. In the renal vasculature, in contrast, adenosine can produce vasoconstriction, a response...... that has been suggested to be an organ-specific version of metabolic control designed to restrict organ perfusion when transport work increases. However, the vasoconstriction elicited by an intravenous infusion of adenosine is only short lasting, being replaced within 1-2 min by vasodilatation. It appears...

  16. Increased Cortical Extracellular Adenosine Correlates with Seizure Termination

    Science.gov (United States)

    Van Gompel, Jamie J.; Bower, Mark R.; Worrell, Gregory A.; Stead, Matt; Chang, Su-Youne; Goerss, Stephan J.; Kim, Inyong; Bennet, Kevin E.; Meyer, Fredric B.; Marsh, W. Richard; Blaha, Charles D.; Lee, Kendall H.

    2014-01-01

    Objective Seizures are currently defined by their electrographic features. However, neuronal networks are intrinsically dependent upon neurotransmitters of which little is known regarding their peri-ictal dynamics. Evidence supports adenosine as having a prominent role in seizure termination, as its administration can terminate and reduce seizures in animal models. Further, microdialysis studies in humans suggest adenosine is elevated peri-ictally, but the relationship to the seizure is obscured by its temporal measurement limitations. Because electrochemical techniques can provide vastly superior temporal resolution, we test the hypothesis that extracellular adenosine concentrations rise during seizure termination in an animal model and humans using electrochemistry. Methods White farm swine (n=45) were used in an acute cortical model of epilepsy and 10 human epilepsy patients were studied during intraoperative electrocorticography (Ecog). Wireless Instantaneous Neurotransmitter Concentration Sensor (WINCS) based fast scan cyclic voltametry (FSCV) and fixed potential amperometry were obtained utilizing an adenosine specific triangular waveform or biosensors respectively. Results Simultaneous Ecog and electrochemistry demonstrated an average adenosine rise of 260% compared to baseline at 7.5 ± 16.9 seconds with amperometry (n=75 events) and 2.6 ± 11.2 seconds with FSCV (n=15 events) prior to electrographic seizure termination. In agreement with these animal data, adenosine elevation prior to seizure termination in a human patient utilizing FSCV was also seen. Significance Simultaneous Ecog and electrochemical recording supports the hypothesis that adenosine rises prior to seizure termination, suggesting that adenosine itself may be responsible for seizure termination. Future work using intraoperative WINCS based FSCV recording may help to elucidate the precise relationship between adenosine and seizure termination. PMID:24483230

  17. QCD Dual

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2009-01-01

    We uncover a novel solution of the 't Hooft anomaly matching conditions for QCD. Interestingly in the perturbative regime the new gauge theory, if interpreted as a possible QCD dual, predicts the critical number of flavors above which QCD in the nonperturbative regime, develops an infrared stable...... fixed point. Remarkably this value is identical to the maximum bound predicted in the nonpertubative regime via the all-orders conjectured beta function for nonsupersymmetric gauge theories.......We uncover a novel solution of the 't Hooft anomaly matching conditions for QCD. Interestingly in the perturbative regime the new gauge theory, if interpreted as a possible QCD dual, predicts the critical number of flavors above which QCD in the nonperturbative regime, develops an infrared stable...

  18. 双能量CT在肾癌诊断及分型中的应用%Application of dual-source dual-energy CT scanning in diagnosis and typing of renal cell carcinoma

    Institute of Scientific and Technical Information of China (English)

    金原; 武志峰; 吴山; 刘世杰; 王沙沙

    2014-01-01

    Objective To investigate the value of dual-energy virtual unenhanced and dual-energy iodine value distribution diagram type of kidney cancer.Methods A retrospective analysis of 35 cases of renal cell carcinoma dual-energy CT scan data,compared to kidney pathology data,analyze the image quality and radiation dose dual-energy virtual unenhanced and dual energy distribution of iodine in clear cell carcinoma and non-clear cell carcinoma the differences that exist.Results Unenhanced and virtual unenhanced image quality was quite,CT value (routine unenhanced renal parenchyma 31.90±4.10 HU,abdominal aortic 45.60±6.30 HU,psoas 50.00±6.6 HU3,kidney 1.410±17.06 HU; virtual unenhanced renal parenchyma abdominal aortic 33.20±5.50 HU,48.30±8.00 HU,52.40±10.63 HU psoas kidney 0.87±17.48 HU),signal to noise ratio (routine unenhanced renal abdominal aorta 3.22±1.49,5.13±2.57,4.56±2.12 psoas kidney 3.24±2.27 virtual unenhanced renal abdominal aorta 2.73±1.08,3.79±1.64,3.23±1.35 psoas kidney 2.18± 1.57) had not significantly different (P > 0.05).Clear cell carcinoma of the skin medullart junction of iodinedistribution of images Iodine (2.75±1.05) mg/ml was higher than non-clear cell carcinoma (1.25±0.72) mg/ml,the difference was statistically significant (t =7.048,P < 0.05).Conclusions CT examination in patients with renal cell carcinoma virtual unenhanced image quality is similar with routine unenhanced image quality,it reduces radiation dose.The distribution of iodine can provide more diagnostic information that can help us be more intuitive and accurate judgments of the blood supply and kidney cancer subtypes.%目的 探讨双能量CT虚拟平扫及双能量碘分布图在肾癌诊断及分型中的应用价值.方法 收集35例肾癌患者双能量增强CT扫描数据及病理结果,分析双能量CT虚拟平扫的图像质量及辐射剂量、双能量碘分布图在透明细胞癌及非透明细胞癌中存在的差异.结果 虚拟平扫与常规平扫

  19. Adenosine and Preexcitation Variants: Reappraisal of Electrocardiographic Changes.

    Science.gov (United States)

    Ali, Hussam; Lupo, Pierpaolo; Foresti, Sara; De Ambroggi, Guido; Epicoco, Gianluca; Fundaliotis, Angelica; Cappato, Riccardo

    2016-07-01

    Intravenous adenosine is a short-acting blocker of the atrioventricular node that has been used to unmask subtle or latent preexcitation, and also to enable catheter ablation in selected patients with absent or intermittent preexcitation. Depending on the accessory pathway characteristics, intravenous adenosine may produce specific electrocardiographic changes highly suggestive of the preexcitation variant. Herein, we view different ECG responses to this pharmacological test in various preexcitation patterns that were confirmed by electrophysiological studies. Careful analysis of electrocardiographic changes during adenosine test, with emphasis on P-delta interval, preexcitation degree, and atrioventricular block, can be helpful to diagnose the preexcitation variant/pattern.

  20. Possible mechanism of adenosine protection in carbon tetrachloride acute hepatotoxicity. Role of adenosine by-products and glutathione peroxidase.

    Science.gov (United States)

    Chagoya de Sánchez, V; Hernández-Muñoz, R; Yáñez, L; Vidrio, S; Díaz-Muñoz, M

    1995-02-01

    Adenosine proved to be an effective hepatoprotector increasing the survival rate of rats receiving lethal doses of CCl4. Searching for the mechanism of action, we found that adenosine transiently prevents the necrotic liver damage associated to an acute CCl4 treatment. The antilipoperoxidative action of the nucleoside was evidenced by a decrease of TBA-reactive products and the diene conjugates elicited by the hepatotoxin. Adenosine's protective effect was demonstrated by reverting the decrease of cytochrome P-450 while preserved intact the activity of the microsomal enzyme glucose-6-phosphatase. CCl4 promoted an increase in the oxidant stress through an enhancement in oxidized glutathione levels. This action was also completely counteracted by the nucleoside. Adenosine was unable to prevent CCl4 activation and, even, increased .CCl3 formation in the presence of PBN in vivo. However, in the presence of the nucleoside, irreversible binding of 14CCl4 to the microsomal lipid fraction of the treated animals was decreased. These results suggest that adenosine protective action might be exerted at the level of the propagation reaction following CCl4 activation. Two possible mechanisms were associated to the nucleoside protection: (1) the peroxide-metabolyzed enzymes, GSH-per, showed a marked increase after 30 minutes of adenosine treatment, which was potentiated by the hepatotoxin, suggesting an important role of this enzyme in the nucleoside's action; (2) the adenosine catabolism induced an increase in uric acid level, and allopurinol, a purine metabolism inhibitor, prevented such elevation as well as the antilipoperoxidative action of adenosine and the increase of GSH-per associated with the nucleoside treatment. These facts strongly suggest that the protective effect elicited by adenosine is not a direct one, but rather is related to its catabolic products, such as uric acid, which has been recognized as a free radical scavenger.

  1. The application value of dual-source dual-energy CT in the diagnosis and pathology grade of esophageal cancer%双源 CT 能谱曲线在食管癌诊断及其病理分级中的应用价值

    Institute of Scientific and Technical Information of China (English)

    刘小静; 苗重昌; 周胜利

    2016-01-01

    目的:探讨双源 CT 能谱曲线在食管癌诊断及其病理分级中的应用价值。方法60例经内镜或病理证实的食管癌患者行双源双能量模式扫描,两个球管管电压分别为:A 球管100 kV,B 球管140 kV,双能量扫描时两组球管同时工作。将扫描获得的两组数据上传至工作站进行相关后处理及分析:绘制食管癌病灶及正常食管管壁能谱曲线,比较食管癌病灶与正常食管壁、不同分化程度食管癌的能谱曲线特征及其斜率之间的差异与联系。食管癌病理分级依据病理结果。结果①食管癌病灶能谱曲线走行位于正常食管管壁上方,并且斜率高于正常食管壁;②不同分化程度食管癌能谱曲线走行及趋势不同,分化程度越差,曲线走行越靠上,对各组能谱曲线斜率比较可得分化程度越差,能谱曲线斜率越大。结论双源双能量 CT 能谱曲线在食管癌诊断及病理分级中有着一定的临床应用价值。%Objective To explore the application value of spectrum curve dual - energy CT in the diagnosis of esophageal cancer and it′s pathology grade. Methods 60 cases confirmed of esophageal carcinoma by endoscopic or pathology underwent dual source CT dual energy scan mode using two ball tube voltage respectively. Ball tube A was 100 kV,and ball tube B was 140 kV. The two ball tube worked at the same time when the dual energy scan was conducted. The data obtained from the dual energy scan was sent to the workstation for post - processing and analy-sis. The spectrum of esophageal carcinoma and normal esophageal wall was drawn,then the differences and relationship of the spectral curve and the slope between esophageal carcinoma and normal esophageal wall,different grades of esophageal cancer were analyzed and compared. The grade of the esophageal cancer was based on the pathology. Results ①The spectral curve of esophageal cancer was located above the normal esophageal

  2. Preliminary study of dual energy scanning of dual source CT for diagnosing hepatic tumors%双源CT双能量扫描在肝脏肿瘤应用价值的初步探讨

    Institute of Scientific and Technical Information of China (English)

    王翔; 王涛; 王小琴

    2013-01-01

    目的 探讨双源CT(DSCT)双能量扫描在肝脏肿瘤诊断中的应用价值.方法 回顾性分析2011年4~12月该院行DSCT扫描肝脏肿瘤患者20例的临床资料.结果 患者肝脏、脾脏、腹主动脉、脊柱后缘肌肉普通平扫与虚拟平扫(P>0.05),原发性肝癌与胆管细胞癌和肝海绵状血管瘤在碘图中差异有统计学意义(P0. 05). The iodine imaging showed statistical difference between primary liver cancer with bile duct cell carcinoma and hepatic cavernous hemangioma(P<0. 05). Conclusion Dual energy scanning of DSCT has the latent clinical application value in the diagnosis of hepatic tumors.

  3. Correlation between Coronary Artery Stenosis and Plaque Nature Dual-Source Computed Tomography for Coronary Angiography%双源 CT 对冠状动脉狭窄及斑块性质的应用价值

    Institute of Scientific and Technical Information of China (English)

    柏辉; 李国晖

    2015-01-01

    目的:探讨双源CT对冠状动脉狭窄及不同性质冠状动脉斑块的诊断价值。方法:对50例临床确诊及拟诊冠心病患者行双源CT冠状动脉成像(CCTA)检查及冠状动脉造影(CCA),以CCA结果为参考标准,评估双源CT对不同性质斑块所致冠状动脉狭窄的特异度、敏感度、阳性预测值、阴性预测值及准确性,分析狭窄程度与斑块成分间的相关性。结果:与CCA对照,50例患者中,双源CT对诊断冠状动脉狭窄的特异度、敏感度、阳性预测值、阴性预测值依次如下:轻度狭窄分别为98.9%、46.7%、77.8%、95.8%;中度狭窄分别为97.6%、71.0%、84.6%、94.8%;重度狭窄分别为96.6%、96.4%、96.4%、98.6%。误诊冠状动脉狭窄共20支,诊断符合率为89.8%。对非钙化性斑块所致管腔狭窄的诊断符合率达84.3%,高于钙化性斑块(76.9%)。结论:双源CT冠状动脉成像能够有效判断冠状动脉狭窄程度及斑块成分。%Objective: To discuss the diagnosis value for coronary artery of different components of plaque and stenosis by dual-source computed tomography coronary artery imaging.Method:A total of 50 pa-tients diagnosed with coronary heart disease underwent dual-source computed tomography coronary artery ( CCTA) imaging and coronary angiography( CCA) .The specificity,sensitivity, positive predictive value,neg-ative predictive value,and accuracy for the quantitative detection of stenosis assessed.Result:In the 50 pa-tients,The specificity,sensitivity, positive predictive value,negative predictive value and accuracy for the de-tection of coronary artery stenosis assessed with dual-source CT were respectively:for<50 stenosis,98.9%, 46.7%,77.8%,95.8%;for 50 ~74 stenosis,97.6%,71.0%,84.6%,94.8%;for≥75 stenosis,96.6%、96. 4%、96.4%、98.6%.Comparing with CCA,misdiagnosis was observed in 20 of 196 arteries with dual-source CT

  4. Rosuvastatin increases extracellular adenosine formation in humans in vivo: a new perspective on cardiovascular protection.

    OpenAIRE

    Meijer, P; Oyen, W.J.G.; Dekker, D.; Broek, P.H.H. van den; Wouters, C.W.; Boerman, O.C.; Scheffer, G. J.; Smits, P; Rongen, G.A.P.J.M.

    2009-01-01

    OBJECTIVE: Statins may increase extracellular adenosine formation from adenosine monophosphate by enhancing ecto-5'-nucleotidase activity. This theory was tested in humans using dipyridamole-induced vasodilation as a read-out for local adenosine formation. Dipyridamole inhibits the transport of extracellular adenosine into the cytosol resulting in increased extracellular adenosine and subsequent vasodilation. In addition, we studied the effect of statin therapy in a forearm model of ischemia-...

  5. Dual energy perfusion imaging using dual source CT in the diagnosis and clinical application of pulmonary embolism%双源CT双能量肺灌注成像对肺栓塞的诊断和临床应用价值

    Institute of Scientific and Technical Information of China (English)

    周运锋; 史河水; 崔立明; 蒋日峰; 李欣; 刘永华; 韩萍

    2012-01-01

    Objective:To investigate the value of dual energy pulmonary perfusion imaging using dual source CT in the diagnosis and clinical application of pulmonary artery embolism (PE). Methods: Seventy-eight consecutive patients suspected of having PE underwent CT pulmonary arteriography with dual-energy technique on a dual source CT scanner. CT pulmonary arteriography (CTPA) and perfusion blood volume (PBV) images after post-processing of the raw data were obtained. Evaluation of the PBV image quality and typing of PE were performed by two radiologists as well as to observe the presence,location,extent of PE. The PBV appearances and its relationship with CTA images as well as pulmonary parenchyma abnormities were analyzed. The consistency of the 2 observers in evaluating the PBV image quality and typing were examined by Kappa value. The sensitivity,specificity,positive predictive value (PPV) and negative predictive value (NPV) of PBV images for the diagnosis of PE were calculated. Results:The ranking of PBV image quality and typing showed very good agreement between two observers,the K value was 0. 87 and 0. 80, respectively (Pdual energy pulmonary perfusion imaging on dual source CT.%目的:探讨双源CT双能量肺灌注成像对肺动脉栓塞的诊断和临床应用价值.方法:对疑诊肺动脉栓塞的78名患者行双源CT肺动脉成像双能量扫描,数据经后处理得到肺动脉血管图像(CTA)和肺灌注图像(PBV).两位医师对PBV图像进行质量评价和分型,同时观察CTA图像有无栓塞以及栓塞的部位、程度.分析PBV图像的表现与CTA图像、肺部异常改变的关系.用Kappa系数检验两

  6. Sources

    OpenAIRE

    2015-01-01

    SOURCES MANUSCRITES Archives nationales Rôles de taille 1768/71 Z1G-344/18 Aulnay Z1G-343a/02 Gennevilliers Z1G-340/01 Ivry Z1G-340/05 Orly Z1G-334c/09 Saint-Remy-lès-Chevreuse Z1G-344/18 Sevran Z1G-340/05 Thiais 1779/80 Z1G-391a/18 Aulnay Z1G-380/02 Gennevilliers Z1G-385/01 Ivry Z1G-387b/05 Orly Z1G-388a/09 Saint-Remy-lès-Chevreuse Z1G-391a/18 Sevran Z1G-387b/05 Thiais 1788/89 Z1G-451/18 Aulnay Z1G-452/21 Chennevières Z1G-443b/02 Gennevilliers Z1G-440a/01 Ivry Z1G-452/17 Noiseau Z1G-445b/05 ...

  7. Inhibition of uptake of adenosine into human blood platelets

    NARCIS (Netherlands)

    Lips, J.P.M.; Sixma, J.J.; Trieschnigg, A.C.

    1980-01-01

    Adenosine transport into human blood platelets is mediated by two independent systems with different affinities. Both systems transport only purine nucleosides and no pyrimidine nucleosides. In experiments with differently substituted purine nucleosides, purines and analogues, differences in carrier

  8. Cyclic adenosine monophosphate signal pathway in targeted therapy of lymphoma

    Institute of Scientific and Technical Information of China (English)

    DOU Ai-xia; WANG Xin

    2010-01-01

    Objective To review the role of cyclic adenosine monophosphate (cAMP) signal pathway in the pathogenesis oflymphoma and explore a potential lymphoma therapy targeted on this signaling pathway.Data sources The data cited in this review were mainly obtained from the articles listed in Medline and PubMed,published from January 1995 to June 2009. The search terms were "cAMP" and "lymphoma".Study selection Articles regarding the role of the cAMP pathway in apoptosis of lymphoma and associated cells and itspotential role in targeted therapy of lymphoma.Results In the transformation of lymphocytic malignancies, several signal pathways are involved. Among of them, thecAMP pathway has attracted increasing attention because of its apoptosis-inducing role in several lymphoma cells. cAMPpathway impairment is found to influence the prognosis of lymphoma. Targeted therapy to the cAMP pathway seems tobe a new direction for lymphoma treatment, aiming at restoring the cAMP function.Conclusions cAMP signal pathway has different effects on various lymphoma cells. cAMP analogues andphosphodiesterase 4B (PDE4B) inhibitors have potential clinical significance. However, many challenges remain inunderstanding the various roles of such agents.

  9. Adenosine Deaminase Deficiency – More Than Just an Immunodeficiency

    OpenAIRE

    Kathryn Victoria Whitmore; Hubert Bobby Gaspar

    2016-01-01

    Adenosine deaminase (ADA) deficiency is best known as a form of severe combined immunodeficiency (SCID) which results from mutations in the gene encoding adenosine deaminase. Affected patients present with clinical and immunological manifestations typical of a severe combined immunodeficiency. Therapies are currently available that can that target these immunological disturbances and treated patients show varying degrees of clinical improvement. However, there is now a growing body of evidenc...

  10. Low-dose adenosine stress echocardiography: Detection of myocardial viability

    Science.gov (United States)

    Djordjevic-Dikic, Ana; Ostojic, Miodrag; Beleslin, Branko; Nedeljkovic, Ivana; Stepanovic, Jelena; Stojkovic, Sinisa; Petrasinovic, Zorica; Nedeljkovic, Milan; Saponjski, Jovica; Giga, Vojislav

    2003-01-01

    Objective The aim of this study was to evaluate the diagnostic potential of low-dose adenosine stress echocardiography in detection of myocardial viability. Background Vasodilation through low dose dipyridamole infusion may recruit contractile reserve by increasing coronary flow or by increasing levels of endogenous adenosine. Methods Forty-three patients with resting dyssynergy, due to previous myocardial infarction, underwent low-dose adenosine (80, 100, 110 mcg/kg/min in 3 minutes intervals) echocardiography test. Gold standard for myocardial viability was improvement in systolic thickening of dyssinergic segments of ≥ 1 grade at follow-up. Coronary angiography was done in 41 pts. Twenty-seven patients were revascularized and 16 were medically treated. Echocardiographic follow up data (12 ± 2 months) were available in 24 revascularized patients. Results Wall motion score index improved from rest 1.55 ± 0.30 to 1.33 ± 0.26 at low-dose adenosine (p < 0.001). Of the 257 segments with baseline dyssynergy, adenosine echocardiography identified 122 segments as positive for viability, and 135 as necrotic since no improvement of systolic thickening was observed. Follow-up wall motion score index was 1.31 ± 0.30 (p < 0.001 vs. rest). The sensitivity of adenosine echo test for identification of viable segments was 87%, while specificity was 95%, and diagnostic accuracy 90%. Positive and negative predictive values were 97% and 80%, respectively. Conclusion Low-dose adenosine stress echocardiography test has high diagnostic potential for detection of myocardial viability in the group of patients with left ventricle dysfunction due to previous myocardial infarction. Low dose adenosine stress echocardiography may be adequate alternative to low-dose dobutamine test for evaluation of myocardial viability. PMID:12812523

  11. 双源 CT 对主动脉瓣狭窄的诊断价值%Assessment of aortic stenosis with dual-source CT

    Institute of Scientific and Technical Information of China (English)

    王朴飞; 吕梁; 王罡; 杨利鹏; 佘波; 安鸿飞; 周子煜

    2014-01-01

    Objective To discuss the feasibility and accuracy of dual-source CT ( DSCT) in the evaluation of aortic stenosis ( AS) with transthoracic echocardiography ( TTE) as reference.Methods A total of 53 patients who underwent both DSCT and TTE were prospectively evaluated.All of them were assessed by TTE for aortic stenosis.Maximum aortic valve area ( AVA) in systolic phase was measured with DSCT , and was compared to that index obtained from the continuity equation on TTE.The severity of AS was graded as mild , moderate , or severe according to the AVA.Linear regression analysis and Bland-Altman plots were used to compare the AVA measured by using CT and TTE.Agreement on semi-quantitative grades of AS severity between the two methods was tested by using Kappa statistics.Results The mean AVA using DSCT was (1.45 ±0.35 ) cm2 compared to the mean AVA of ( 1.33 ±0.36 ) cm2 using TTE, with a significant correlation between them (r=0.92,P<0.01).Bland-Altman analysis demonstrated good inter-modality consistency between DSCT and TTE.However , DSCT demonstrated a slight overestimation of the AVA compared to TTE.As identified by TTE, there were 53 patients with AS, 13 with mild AS, 21 with moderate AS , and 19 with severe AS.In 3 patients DSCT showed no AS , TTE detected mild AS.In 6 cases, TTE had graded the stenosis as moderate , but the stenosis degree was graded as mild using DSCT.Kappa analysis showed a good agreement between the two methods on semi -quantitative grades of aortic stenosis severity (Kappa=0.75,P<0.01).Conclusion AVA measurements using DSCT is feasible and reasonably accurate for those patients with moderate to severe aortic stenosis.%目的:以经胸心脏超声(TTE)为对照,探讨双源CT(DSCT)评估主动脉瓣狭窄(AS)的可行性及准确性。方法回顾性分析53例行DSCT冠状动脉成像及TTE检查,经TTE诊断均为AS的患者。 DSCT面积法测量收缩期最大主动脉瓣口面积(AVA),TTE采用连续性方程计

  12. The A3 adenosine receptor: history and perspectives.

    Science.gov (United States)

    Borea, Pier Andrea; Varani, Katia; Vincenzi, Fabrizio; Baraldi, Pier Giovanni; Tabrizi, Mojgan Aghazadeh; Merighi, Stefania; Gessi, Stefania

    2015-01-01

    By general consensus, the omnipresent purine nucleoside adenosine is considered a major regulator of local tissue function, especially when energy supply fails to meet cellular energy demand. Adenosine mediation involves activation of a family of four G protein-coupled adenosine receptors (ARs): A(1), A(2)A, A(2)B, and A(3). The A(3) adenosine receptor (A(3)AR) is the only adenosine subtype to be overexpressed in inflammatory and cancer cells, thus making it a potential target for therapy. Originally isolated as an orphan receptor, A(3)AR presented a twofold nature under different pathophysiologic conditions: it appeared to be protective/harmful under ischemic conditions, pro/anti-inflammatory, and pro/antitumoral depending on the systems investigated. Until recently, the greatest and most intriguing challenge has been to understand whether, and in which cases, selective A(3) agonists or antagonists would be the best choice. Today, the choice has been made and A(3)AR agonists are now under clinical development for some disorders including rheumatoid arthritis, psoriasis, glaucoma, and hepatocellular carcinoma. More specifically, the interest and relevance of these new agents derives from clinical data demonstrating that A(3)AR agonists are both effective and safe. Thus, it will become apparent in the present review that purine scientists do seem to be getting closer to their goal: the incorporation of adenosine ligands into drugs with the ability to save lives and improve human health.

  13. Low-dose adenosine stress echocardiography: Detection of myocardial viability

    Directory of Open Access Journals (Sweden)

    Nedeljkovic Milan

    2003-06-01

    Full Text Available Abstract Objective The aim of this study was to evaluate the diagnostic potential of low-dose adenosine stress echocardiography in detection of myocardial viability. Background Vasodilation through low dose dipyridamole infusion may recruit contractile reserve by increasing coronary flow or by increasing levels of endogenous adenosine. Methods Forty-three patients with resting dyssynergy, due to previous myocardial infarction, underwent low-dose adenosine (80, 100, 110 mcg/kg/min in 3 minutes intervals echocardiography test. Gold standard for myocardial viability was improvement in systolic thickening of dyssinergic segments of ≥ 1 grade at follow-up. Coronary angiography was done in 41 pts. Twenty-seven patients were revascularized and 16 were medically treated. Echocardiographic follow up data (12 ± 2 months were available in 24 revascularized patients. Results Wall motion score index improved from rest 1.55 ± 0.30 to 1.33 ± 0.26 at low-dose adenosine (p Conclusion Low-dose adenosine stress echocardiography test has high diagnostic potential for detection of myocardial viability in the group of patients with left ventricle dysfunction due to previous myocardial infarction. Low dose adenosine stress echocardiography may be adequate alternative to low-dose dobutamine test for evaluation of myocardial viability.

  14. Osteitis: a retrospective feasibility study comparing single-source dual-energy CT to MRI in selected patients with suspected acute gout

    Energy Technology Data Exchange (ETDEWEB)

    Diekhoff, Torsten [Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Berlin (Germany); Charite - Universitaetsmedizin Berlin, Department of Radiology (CCM), Berlin (Germany); Scheel, Michael; Hamm, Bernd; Hermann, Kay-Geert A. [Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Berlin (Germany); Hermann, Sandra [Charite - Universitaetsmedizin Berlin Campus Mitte, Department of Rheumatology and Clinical Immunology, Berlin (Germany); Mews, Juergen [Toshiba Medical Systems Europe, BV, Zoetermeer (Netherlands)

    2017-02-15

    Dual-energy computed tomography detects tophi in patients with chronic gout. However, other information that can be obtained from the same scan is not the focus of the current research, e.g., the detection of bone marrow edema (BME) using virtual bone marrow imaging (VBMI). The aim of this study was to evaluate if BME in patients with acute arthritis can be detected with VBMI using magnetic resonance imaging (MRI) as the standard of reference. This retrospective study included 11 patients who underwent both MRI and dual-energy computed tomography (mean interval of 40 days). BME in MRI (standard of reference) and VBMI was judged independently by two different blinded readers. φ-correlation coefficient and Cohen's κ were performed for statistical analysis. Approval was waived by the IRB. Two patients with a final diagnosis of RA and one with septic arthritis showed osteitis on MRI and VBMI. However, in each case, there were individual bones identified with osteitis on MRI but not VBMI. Three additional patients with the final diagnosis of RA were identified correctly as negative for BME. There was a good correlation between both modalities (φ = 0.8; κ = 0.8). Inter-rater reliability was excellent for both modalities (κ = 0.9). We have shown that detecting osteitis using VBMI is feasible in patients with inflammatory arthritis. Further studies are needed on larger, more-targeted populations to better define the indications, accuracy, and added value of this technique. (orig.)

  15. Heat pump using dual heat sources of air and water. Performance in cooling mode; Mizu kuki ryonetsugen heat pump no kenkyu. Reibo unten ni okeru seino

    Energy Technology Data Exchange (ETDEWEB)

    Ito, S.; Miura, N. [Kanagawa Institute of Technology, Kanagawa (Japan); Uchikawa, Y. [Kubota Corp., Osaka (Japan)

    1997-11-25

    When a heat pump is used for cooling purpose, it is possible to utilize different kinds of waste water as high-heat sources. However, these heat sources would have their temperatures vary with seasons and time in a day. Therefore, a discussion was given on performance of a heat pump when water and air heat sources are used for condensers during cooling operation independently, in series and in parallel, respectively. The air condenser shows an equivalent COP as compared with the water condenser when air temperature is lower by about 8 degC than water temperature. At the same heat source temperature, the COP for the water condenser indicated a value higher by about 0.6 than the case of the air condenser. A method to use condensers in parallel experiences little contribution from the air heat source, and performance of the heat pump decreases below the case of using the water heat source independently when the air heat source temperature becomes higher than that of the water heat source. In the case of series use in which a water condenser is installed in front and an air condenser in rear, its effect is exhibited when temperature in the air heat source is lower than that in the water heat source. Better performance was shown than in operating the water heat source independently. 2 refs., 9 figs.

  16. Thoracic applications of dual energy.

    Science.gov (United States)

    Remy-Jardin, Martine; Faivre, Jean-Baptiste; Pontana, Francois; Hachulla, Anne-Lise; Tacelli, Nunzia; Santangelo, Teresa; Remy, Jacques

    2010-01-01

    Recent technological advances in multidetector computed tomography (CT) have led to the introduction of dual-source CT, which allows acquisition of CT data at the same energy or at 2 distinct tube voltage settings during a single acquisition. The advantage of the former is improvement of temporal resolution, whereas the latter offers new options for CT imaging, allowing tissue characterization and functional analysis with morphologic evaluation. The most investigated application has been iodine mapping at pulmonary CT angiography. The material decomposition achievable opens up new options for recognizing substances poorly characterized by single-energy CT. Although it is too early to draw definitive conclusions on dual-energy CT applications, this article reviews the results already reported with the first generation of dual-source CT systems.

  17. 双源双能量CT对新疆南疆地区儿童输尿管结石的诊断价值%The Value of Dual-source Dual-energy CT in the Diagnosis of Ureteral Cal-culi in Children in Southern Xinjiang

    Institute of Scientific and Technical Information of China (English)

    马依迪丽·尼加提; 田序伟

    2015-01-01

    Objective To explore the application value of low-dose dual-source dual-energy CT in the diagnosis of urinary tract stones in children. Methods This study will explore the dual energy CT technology in southern xinjiang xinjiang regional chil-dren's disease diagnosis and differential diagnosis of ureteral calculi application value, and the image quality, the signal-to-noise ratio, lesion detection rate and identify differences, evaluate the feasibility of its application in clinical, 56 children cases CT in-spection and ultrasonic inspection group, analysis between the two groups statistically for difficult diagnosis of ureteral calculi. Results The dual source CT dual energy diagnosis of 56 cases of ureteral calculi children, all cases by ultrasound, including 1 case of abdominal segment, 3 cases of basin section, 2 cases of multiple ultrasound was not diagnosed or missed diagnosis of ureteral calculi. CT in the diagnosis of 47 cases with kidney seeper, 14 patients with moderately severe water, 9 cases with merger of urinary tract infection, 2 cases of diagnosis of urinary tuberculosis, 1 case of neurogenic bladder. Conclusion Low-dose CT in the diagnosis of dual energy not diagnosed with routine inspection method and its complications, complications were found very good diagnostic value.%目的:双源双能量低剂量CT在诊断儿童泌尿系结石中的应用价值。方法该研究将探究采用双能量CT技术在新疆南疆地区儿童输尿管结石疾病诊断和鉴别诊断的意义,然后比较其图像质量、信噪比、病变检出率这几方面,分析其在临床诊断中的可行性,将56例儿童病例分CT检查组及超声检查组,分析两组间对于难诊断型输尿管结石的统计学差异。结果双源双能量CT诊断输尿管结石儿童56例,所有病例均经过B超检查,其中1例腹段、3例盆段、2例多发输尿管结石B超未诊出或漏诊;CT诊断47例有肾积水、其中14例伴有中重度积水,9

  18. 1-(beta-D-Erythrofuranosyl)adenosine.

    Science.gov (United States)

    Kline, Paul C; Zhao, Hongqiu; Noll, Bruce C; Oliver, Allen G; Serianni, Anthony S

    2010-04-01

    The title compound, also known as beta-erythroadenosine, C(9)H(11)N(5)O(3), (I), a derivative of beta-adenosine, (II), that lacks the C5' exocyclic hydroxymethyl (-CH(2)OH) substituent, crystallizes from hot ethanol with two independent molecules having different conformations, denoted (IA) and (IB). In (IA), the furanose conformation is (O)T(1)-E(1) (C1'-exo, east), with pseudorotational parameters P and tau(m) of 114.4 and 42 degrees, respectively. In contrast, the P and tau(m) values are 170.1 and 46 degrees, respectively, in (IB), consistent with a (2)E-(2)T(3) (C2'-endo, south) conformation. The N-glycoside conformation is syn (+sc) in (IA) and anti (-ac) in (IB). The crystal structure, determined to a resolution of 2.0 A, of a cocrystal of (I) bound to the enzyme 5'-fluorodeoxyadenosine synthase from Streptomyces cattleya shows the furanose ring in a near-ideal (O)E (east) conformation (P = 90 degrees and tau(m) = 42 degrees) and the base in an anti (-ac) conformation.

  19. Different efficacy of adenosine and NECA derivatives at the human A3 adenosine receptor: insight into the receptor activation switch.

    Science.gov (United States)

    Dal Ben, Diego; Buccioni, Michela; Lambertucci, Catia; Kachler, Sonja; Falgner, Nico; Marucci, Gabriella; Thomas, Ajiroghene; Cristalli, Gloria; Volpini, Rosaria; Klotz, Karl-Norbert

    2014-01-15

    A3 Adenosine receptors are promising drug targets for a number of diseases and intense efforts are dedicated to develop selective agonists and antagonists of these receptors. A series of adenosine derivatives with 2-(ar)-alkynyl chains, with high affinity and different degrees of selectivity for human A3 adenosine receptors was tested for the ability to inhibit forskolin-stimulated adenylyl cyclase. All these derivatives are partial agonists at A3 adenosine receptors; their efficacy is not significantly modified by the introduction of small alkyl substituents in the N(6)-position. In contrast, the adenosine-5'-N-ethyluronamide (NECA) analogs of 2-(ar)-alkynyladenosine derivatives are full A3 agonists. Molecular modeling analyses were performed considering both the conformational behavior of the ligands and the impact of 2- and 5'-substituents on ligand-target interaction. The results suggest an explanation for the different agonistic behavior of adenosine and NECA derivatives, respectively. A sub-pocket of the binding site was analyzed as a crucial interaction domain for receptor activation.

  20. 46 CFR 183.324 - Dual voltage generators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Dual voltage generators. 183.324 Section 183.324... TONS) ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.324 Dual voltage generators. (a) A dual voltage generator installed on a vessel shall be of the grounded type, where: (1)...

  1. 双源 CT 双能量虚拟平扫对脂肪肝的诊断价值%The diagnostic value of dual energy virtual non-contrast images in hepatic steatosis with dual source CT scanner

    Institute of Scientific and Technical Information of China (English)

    王士阗; 王萱; 王禨; 徐凯; 薛华丹; 金征宇

    2014-01-01

    _目的:探讨双源 CT 双能量腹部虚拟平扫对脂肪肝的诊断价值。方法:回顾性分析采用双源 CT 行腹部双能量增强扫描诊断为脂肪肝的77例患者的平扫期(120 kV)及虚拟平扫(VNC)图像。虚拟平扫图像运用门脉期双能量(100及140 kV)图像重建而来。选择肝门层面测量真实平扫(TNC)与 VNC 图像上肝右叶、肝左叶、脾脏、下腔静脉的 CT 值及噪声,并在肝门层面测量上腹部前后径及左右径。记录整个扫描和平扫期对应的剂量长度乘积(DLP)。评价 TNC 与VNC 图像间各 CT 值及噪声的差异,分析两组图像上肝右叶噪声与前后径、左右径及平均径的关系。分别用肝/脾 CT 值比<0.8、肝/下腔静脉 CT 值比<1.0,做为诊断中重度脂肪肝的标准,比较 TNC 和 VNC 图像诊断中重度脂肪肝的一致性。结果:VNC 图像上肝左叶、右叶及脾脏的 CT 值均高于 TNC(P<0.01),差异小于10 HU。VNC 图像上各部位噪声均低于 TNC。TNC 图像上,肝右叶噪声与前后径、左右径、平均径均有中等相关性(r=0.562,0.608,P<0.01);在 VNC图像上,肝右叶噪声与上述径线值相关性弱。用肝/脾 CT 值比<0.8作为诊断重度脂肪肝的标准,VNC 与 TNC 图像诊断重度脂肪肝一致性的 kappa 值为0.591;用肝/静脉 CT 值比<1.0作为诊断标准,两种图像一致性的 kappa 值为0.458。用 VNC 代替 TNC 图像,可降低24.2%的总扫描剂量。结论:VNC 图像与 TNC 图像在诊断中重度脂肪肝上具有中等的一致性,推荐运用肝/脾 CT 值比<0.8这一诊断标准。%To investigate the value of dual energy (DE)virtual non-contrast (VNC)images in the diagno-sis of hepatic steatosis.Methods:This retrospective study was based on contrast enhanced abdominal DECT scan of 77 pa-tients with hepatic steatosis.The VNC images were reconstructed from two sets of

  2. Dual source spiral CT three dimensional reconstruction in the interventional treatment of liver cancer%双源螺旋CT三维重建技术在肝癌介入治疗中的应用

    Institute of Scientific and Technical Information of China (English)

    王东林; 陈广礼

    2011-01-01

    目的 探讨双源螺旋CT三维重建技术在肝癌介入治疗中的应用价值.方法 对37例肝癌患者进行双源螺旋CT扫描诊断后,在后处理工作站进行容积再现(VR)、最大密度投影(MIP)血管重建.结果 肝动脉期VR图像和MIP多平面重建图像均能清晰显示腹腔干、脾动脉、肝总动脉左右动脉及其2~3级分支,还能清晰显示1~6级门静脉血管结构及1~3级肝静脉血管分支,具有较强的空间立体感.结论 双源螺旋CT门静脉三维重建成像是一种快捷而有效的无创性血管造影技术,有助于临床治疗方案的合理选择及疗效随访.%Objective To investigate the value of dual source spiral CT three dimensional reconstruction in the interventional treatment. Methods Totally 37 patients with liver cancer for dual source spiral CT scan diagnosis, in the post -processing workstation for volume rendering ( VR), maximum intensity projection (MIP) revascularization. Results The hepatic arterial phase MIP,VR images and multiplanar reconstruction images could clearly show the celiac trunk, splenic artery, hepatic artery about 2 ~ 3 artery and its branches, but also clearly show the 1 ~ 6 Class doors and 1 vein structure three branches of hepatic veins, with a strong spatial dimension. Conclusions The dual source spiral CT three dimensional reconstruction of portal vein imaging is a fast and effective non - invasive vascular imaging techniques, useful in clinical treatment choice and efficacy of a reasonable follow - up.

  3. The value of dual-source dual-energy CT angiography in the diagnosis of carotid artery stenosis%双能量颈部CT血管成像诊断颈动脉狭窄性病变的价值

    Institute of Scientific and Technical Information of China (English)

    郑玲; 周长圣; 赵艳娥; 张龙江; 李敏; 刘德志; 卢光明

    2011-01-01

    Objective Carotid artery stenosis is one of the important causes of ischemic cerebrovascular diseases, for which angiography remains a chief diagnostic option. Dual-source dual-energy CT, as a newly developed technique, has its unique superiority in angiography, but reports have not seen on its application to the diagnosis of carotid artery stenosis. The authors evaluated dual-source dual-energy CT angiography ( CTA) in the diagnosis of carotid artery stenosis by comparing it with digital subtraction angiography ( DSA). Methods Forty patients first underwent dual-source dual-energy CTA and then DSA of the carotid artery within two weeks. The carotid artery was classified into common carotid artery, extracranial internal carotid artery and intracranial internal carotid artery. Carotid stenosis was rated as mild ( ≤29% ) , moderate (30% -69% ) , severe (70% - 99% ) and occlusion ( 100% ) in the analyses of CTA and DSA images. The sensitivity, specificity, accuracy, PPV and NPV of CTA in the diagnosis of carotid artery stenosis were calculated with DSA as the reference standard. Results Of 240 vessel segments in 40 patients, CTA displayed 70 with various de- grees of stenosis (mild; n = 35, moderate; n = 25, and severe; n = 10) and 170 normal segments, while DSA exhibited 75 with various degrees of stenosis (mild; n = 38, moderate; n = 24, and severe; n = 13) and 165 normal segments. With DSA as the reference standard, the sensitivity, specificity, accuracy, PPV and NPV of CTA in the detection of carotid artery stenosis were 92.0% (69/75) , 99. 4% (164/165), 97.1% (233/240), 98.6% (69/70), and 96. 5% (164/170), respectively. Conclusion Dual-source dual-energy CTA has a high sensitivity in the detection of carotid artery stenosis, which can be used in the screening and diagnosis of carotid artery stenosis as a routine modality.%目的 颈动脉狭窄是缺血性脑血管疾病发病的重要原因之一,目前,临床仍采用常规血管造影的方法对该病进

  4. Integrated characterization of natural attenuation of a PCE plume after thermal remediation of the source zone - incl. dual isotope and microbial techniques

    DEFF Research Database (Denmark)

    Broholm, Mette Martina

    PCE DNAPL contamination at the former central dry cleaning facility in Rødekro, Denmark, was subject to thermal (steam) source zone remediation in late 2006. A > 2 km long plume of chlorinated ethenes (PCE and chlorinated degradation products) which has migrated downgradient from the source zone...

  5. Role of A3 adenosine receptor in diabetic neuropathy.

    Science.gov (United States)

    Yan, Heng; Zhang, Enshui; Feng, Chang; Zhao, Xin

    2016-10-01

    Neuropathy is the most common diabetic complication. Although the A1 and A2A adenosine receptors are important pharmacological targets in alleviating diabetic neuropathy, the role of the A3 adenosine receptor remains unknown. Because the A3 adenosine receptor regulates pain induced by chronic constriction injury or chemotherapy, its stimulation might also attenuate diabetic neuropathy. This study examines the effects of systemic treatment with the A3 adenosine receptor agonist 1-deoxy-1-[6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-N-methyl-β-d-ribofuranuronamide (IB-MECA) on diabetic neuropathy and explores the putative mechanisms underlying its pharmacological effects. We show that IB-MECA alleviated mechanical hyperalgesia and thermal hypoalgesia in mice 2 weeks but not 4 weeks after streptozocin (STZ) treatment. Furthermore, IB-MECA prevented the reduction in sciatic motor nerve conduction velocity and sensory nerve conduction velocity in diabetic mice 2 weeks but not 4 weeks after STZ treatment. Similarly, IB-MECA inhibited the activation of nuclear factor-κB and decreased the generation of tumor necrosis factor-α in the spinal cord of mice 2 weeks but not 4 weeks after STZ treatment. These phenomena were associated with reduction of A3 adenosine receptor expression in the spinal cord after long-term diabetes. Our results suggest that the A3 adenosine receptor plays a critical role in regulating diabetic neuropathy and that reduction in A3 adenosine receptor expression/function might contribute to the progression of diabetic neuropathy. © 2016 Wiley Periodicals, Inc.

  6. 双源CT肺动脉成像在肺动脉栓塞诊断中的应用价值%Application of dual-source CT pulmonary angiography in the diagnosis of pulmonary embolism

    Institute of Scientific and Technical Information of China (English)

    张谷青; 陈月芹; 孙新海; 史志涛; 张新东; 王皆欢

    2011-01-01

    Objective : To explore the value of dual-source CT angiography of pulmonary arteries in the diagnosis of pulmonary embolism. Methods: 58 patients suspected of having pulmonary embolism were examined with dual-source CT pulmonary angiography. The effects of imaging in displaying pulmonary embolism on MPR , MIP , VR and CTVE were compared. The direct signs, the indirect signs and types were analyzed. Results : 45 cases with pulmonary embolism were diagnosed. A total of 658 emboli were found by dual-source CT , 170 of which were central type, 208 were eccentric type , 74 were mural type,and 206 were complete occlusion type. Indirect signs included mosaic sign (13 cases) , pleural effusion (27 cases) ,pulmonary artery hypertension (7 cases) , and pulmonary infarct (18 cases). 658 emboli were found on MPR,584 on MIP.the effect of VR and CTVE were not good (249 and 75 emboli were found). MIP,VR and CTVE were obviously inferior to MPR (P<0.05). Conclusion : The dual-source CT pulmonary angiography is a convenient, fast and reliable method for demonstration of pulmonary embolism. MPR, MIP,VR and CTVE play an important role in the diagnosis of pulmonary embolism.and MPR is the best among them.%目的:探讨双源CT肺动脉成像对肺动脉栓塞(PE)的诊断价值.方法:对58例临床拟诊为PE的患者行双源CT肺动脉成像,总结PE的直接、间接征象及分型,并比较MPR、MIP、VR和CTVE对肺动脉栓子的显示效果.结果:直接征象:58例中45例诊断为PE,共发现栓子 658支(中心型170支,偏心型208支,附壁型74支,完全闭塞型206支).间接征象:马赛克征13例,胸腔积液27例,肺动脉高压7例,肺梗死18例.MPR检出栓子658支,MIP检出584支,VR及CTVE对栓子的显示效果较差,分别为249支和75支.MIP、VR及CTVE对栓子的显示效果低于MPR,差异有统计学意义(P<0.05).结论:双源CT肺动脉成像能够方便、快捷、清楚地显示肺动脉栓子,对诊断PE有重要价值;MPR、MIP、VR和CTVE是

  7. Preliminary study of application value dual-source CT combined with manometric examination on OSAHS%探讨气道双源CT和测压检查对OSAHS的联合应用价值

    Institute of Scientific and Technical Information of China (English)

    王志文; 许凌云; 张晓馨

    2013-01-01

    目的 初步探讨应用双源CT联合测压法评价OSAHS患者上气道阻塞层面的应用价值.方法 通过上气道双源CT判定结果与测压结果进行对照研究,并分析两种方法联合应用判定阻塞层面临床应用价值.结果 双源CT检查判定OSAHS患者上气道狭窄平面的阳性率为83.33%(25/30).AG200判定OSAHS患者上气道间隙阻塞的阳性率为90%(27/30).两种检查结合的阳性率可以达到96.66%(29/30).结论 双源CT检查和AG200对OSAHS患者上气道阻塞均具有诊断意义,CT检查可以反映上气道多平面联合狭窄和上气道解剖性狭窄的原因,AG200仅能单纯显示单一平面的阻塞情况.联合应用两种检查手段可以明显提高OSAHS患者诊断的阳性率,并且在形态学和功能状态表现上可以相互弥补不足,为临床提供更可靠治疗依据.%Objective To preliminarily diseuss the application value of dual-source CT combined with manometric method for evaluation of upper airway obstruction level in patients with OSAHS. Methods Through the upper airway of dual-source CT judgement result, manometric findings were compared. We combined the two methods to determine the clinical value of block level. Results Dositive rate with dual-source CT scan determining the upper airway stenosis in patients with OSAHS was 83. 33% (25/30) , AG200 determining OSAHS patients on positive airway obstruction clearance rate was 90%(27/30). Two kinds of checks can be achieved with the positive rate of 96. 66% (29/30). Conclusion Dual-source CT and AG200 of the upper airway obstruction in patients with OSAHS can make a diagnosis, CT examination can reflect on the multi-planar joint narrow airway and upper airway anatomic stenosis of the reasons, AG200 alone showed only a single plane of obstruction. Combination of two kinds of inspection methods can significantly improve the positive rate of diagnosis of OSAHS patients. And morphological and functional status in each other can

  8. 双源双能量CT评价兔VX2移植瘤介入术疗效的实验研究%The laboratory research of dual-source and dual-energy CT in evaluating the effect of rabbit VX2 tumor interventional therapy

    Institute of Scientific and Technical Information of China (English)

    祁克信; 劳群; 贾玉柱

    2013-01-01

    Objective To explore the diagnostic value of the dual-energy technique with dual-source in the evaluation of therapeutic effect of interventional therapy for hepatocarcinoma.Methods 8 rabbits with tumor growing well were treated with intervention operation,paralleled with double energy CT scan and focal area image,CT and color order change were measured by dual energy liver OVERLAY workstation.Meanwhile,The necrosis and survival of tumor were evaluated by dual energy CT after hepatocarcinoma intervention therapy.Results Taking pathologic diagnosis as gold standard,compared with imaging and pathological results in the order of black,red,orange and red,accuracies were 87.2%,72.3%,71.5% and 83.6% respectively.Sensitivities were 95.1%,37.4%,54.7% and 63.8% respectively.Specificities were 85.4%,86.3%,81.5% and 85.8% respectively.Positive predictives value were 61.4%,54.2%,62.4% and 55.6% respectively.Negative predictive values were 96.3%,76.2%,79.7% and 91.3 % respectively.According to the Spearman relevance analysis,there was strong positive correlation between survival of tumor cells and image color scale (r =12.35,P < 0.05).Conclusion The necrosis and survival of tumor cells in rabbit VX2 liver tumor model can be preliminarily reflected by dual source CT dual energy enhancement scanning.The results provide good reference to the application of dual-source and dual-energy in clinical diagnosis and treatment.%目的 探讨双源双能量CT评价肝癌介入治疗疗效的价值.方法 8只生长良好的荷瘤兔,行介入手术,并进行双源双能量CT扫描,利用双源工作站OVERLAY信息图像,测量病灶区CT值,并记录其色阶变化,探讨双能量CT在肝癌介入治疗后肿瘤存活与坏死情况.结果 以全部的病理诊断为金标准,经过病理和影像对照分析,按黑色、暗红色、红色、橘红色顺序,色阶准确度分别为87.2%、72.3%、71.5%、83.6%,敏感度分别为95.1

  9. Intracoronary adenosine improves myocardial perfusion in late reperfused myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Background Myocardial perfusion associates with clinical syndromes and prognosis.Adenosine could improve myocardial perfusion of acute myocardial infarction within 6 hours,but few data are available on late perfusion of myocardial infarction (MI).This study aimed at quantitatively evaluating the value of intracoronary adenosine improving myocardial perfusion in late reperfused MI with myocardial contrast echocardiography(MCE).Methods Twenty-six patients with anterior wall infarcts were divided randomly into 2 groups:adenosine group(n=12) and normal saline group(n=14).Their history of myocardial infarction was about 3-12 weeks.Adenosine or normalsaline was given when the guiding wire crossed the lesion through percutaneous coronary intervention(PCI),then the balloon was dilated and stent(Cypher/Cypher select)was implanted at the lesion.Contrast pulse sequencing MCE with Sonovue contrast via the coronary route was done before PCI and 30 minutes after PCI.Video densitometry and contrast filled-blank area were calculated with the CUSQ off-line software.Heart function and cardiac events were followed up within 30 days.Results Perfusion in the segments of the criminal occlusive coronary artery in the adenosine group was better than that in the saline group(5.71±0.29 vs 4.95±1.22,P<0.05).Ischemic myocardial segment was deminished significantly afterPCI,but the meliorated area was bigger in the adenosine group than in the saline group((1.56±0.60)cm2 vs(1.02±0.56) cm2,P<0.05).The video densitometry in critical segments was also improved significantly in the adenosine group (5.53±0.36 vs 5.26±0.35,P<0.05).Left ventricular ejection fraction(LVEF)was improved in all patients after PCI,but EF was not significant between the two groups((67±6)% vs(62±7)%,P>0.05).There was no in-hospital or 30-day major adverse cardiac event(MACE)in the adenosine group but 3 MACE in the saline group in 30 days after PCI.Conclusions Adenosine could improve myocardial microvascular

  10. Differential adenosine sensitivity of diaphragm and skeletal muscle arterioles.

    Science.gov (United States)

    Aaker, Aaron; Laughlin, M H

    2002-09-01

    The hyperemic response in exercising skeletal muscle is dependent on muscle fiber-type composition and fiber recruitment patterns, but the vascular control mechanisms producing exercise hyperemia in skeletal muscle remain poorly understood. The purpose of this study was to test the hypothesis that arterioles from white, low-oxidative skeletal muscle are less responsive to adenosine-induced dilation than are arterioles from diaphragm (Dia) and red, high-oxidative skeletal muscle. Second-order arterioles (2As) were isolated from the white portion of gastrocnemius muscle (WG; low-oxidative, fast-twitch muscle tissue) and two types of high-oxidative skeletal muscle [Dia and red portion of gastrocnemius muscle (RG)] of rats. Results reveal that 2As from all three types of muscle dilated in response to the endothelium-dependent dilator acetylcholine (WG: 48 +/- 3%, Dia: 51 +/- 3%, RG: 74 +/- 3%). In contrast, adenosine dilated only 2As from WG (48 +/- 4%) and Dia (46 +/- 5%) but not those from RG (5 +/- 5%). Thus adenosine-induced dilator responses differed among 2As of these different types of muscle tissue. However, the results do not support our hypothesis because 2As from Dia and WG dilated in response to adenosine, whereas 2As from RG did not. We conclude that the adenosine responsiveness of 2As from rat skeletal muscle cannot be predicted only by the fiber-type composition or oxidative capacity of the skeletal muscle tissue wherein the arteriole lies.

  11. Adenosine 5 '-triphosphate (ATP) supplements are not orally bioavailable: a randomized, placebo-controlled cross-over trial in healthy humans

    NARCIS (Netherlands)

    Arts, I.C.W.; Coolen, E.J.C.M.; Bours, M.J.L.; Huyghebaert, N.; Cohen Stuart, M.A.; Bast, A.; Dagnelie, P.C.

    2012-01-01

    Background: Nutritional supplements designed to increase adenosine 5'-triphosphate (ATP) concentrations are commonly used by athletes as ergogenic aids. ATP is the primary source of energy for the cells, and supplementation may enhance the ability to maintain high ATP turnover during high-intensity

  12. Effect of amount and source of manganese and/or phytase supplementation on productive and reproductive performance and some physiological traits of dual purpose cross-bred hens in the tropics.

    Science.gov (United States)

    Attia, Y A; Qota, E M; Bovera, F; Tag El-Din, A E; Mansour, S A

    2010-04-01

    1. The effect of different amounts of added manganese (Mn) (0, 10, 20 and 40 mg/kg) in inorganic and organic form and phytase (0 and 300 U) was investigated on productive, reproductive and haematological traits on 480 hens and 60 cocks (Inchas breeds) divided into 12 groups: 10 and 20 Mn x 0 and 300 phytase x 2 Mn sources (8 groups), two negative controls (0 Mn x 2 levels of phytase) and two positive controls (40 Mn x 2 Mn sources). 2. Phytase supplementation increased laying rate by 1.1% and egg weight by 0.4 g. 3. Manganese supplementation at 10 mg/kg over dietary sources improved hatchability, at 20 mg/kg decreased death embryos and abnormality as those of hens supplemented with 40 mg/kg Mn. Inorganic Mn at 10 mg/kg significantly increased egg mass compared to the organic form. Inorganic Mn was more efficient in decreasing abnormal chicks than organic Mn. Phytase supplementation significantly increased hatchability of fertile eggs and decreased the number of abnormal chicks of groups fed on diets unsupplemented with Mn and those supplemented with 10 mg/kg Mn. 4. Mn supplementation at 10 mg/kg over dietary sources significantly improved sperm mass motility and decreased abnormal sperm. Phytase significantly decreased lymphocyte cells and plasma AST. 5. Mn supplementation of the control diet (containing only 16 mg/kg from raw materials) with 20 mg/kg of Mn from either organic or inorganic source is adequate to support egg production traits, egg quality, reproductive traits and economic efficiency of dual purpose cross-bred hens; however, phytase supplementation may reduce the required Mn supplementation to 10 mg/kg.

  13. Behavior and stability of adenosine triphosphate (ATP) during chlorine disinfection.

    Science.gov (United States)

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

    Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems.

  14. 双源CT对泌尿系结石成分的定性诊断价值评价%The valuation of dual source CT for diagnosis of urinary stone composi-tion

    Institute of Scientific and Technical Information of China (English)

    马海鸿; 周应恩; 赵波

    2015-01-01

    Objective To investigate the diagnostic value of dual source CT on urinary stone constituents qualitative,aims to improve the correct diagnosis rate and the clinical curative effect. Methods Selected 53 patients with suspected urinary calculi hospitalized because of abdominal pain in our hospital from August 2014 to December 2014, 53 patients with suspected urinary calculi treated with dual source CT scan, stone composition, compared with stone infrared spectrum analysis results after the operation were analyzed. Results Dual source CT showed a total of 42 cases patients with gallstone,89 stones,postoperative infrared spectroscopy confirmed that a total of 35 cases of gallstone patients,a total of 66 star stone. There were stone of 8 components, mainly oxalic acid calculi, 30 patients, 59(89.4%) stones;followed by uric acid calculi in 3 cases,4(6.2%),2 cases of other stones 3(4.4%). Dual source CT showed containing calcium oxalate stone 76,accounting for all the stones of the 85.4%(76/89),spectrum proved that the 59(77.6%). Du-al energy that contain calcium oxalate (59/62) with accuracy of 95.2%, sensitivity 100%, specificity 61.0%(36/59),and negative predictive value of 100%. Pure calcium oxalate(20/59)with accuracy of 38.9%,sensitivity of 100%,and negative predictive value of 100%. Conclusion Using dual source CT in diagnosis of urinary calculi in the analysis of the composition of the stones in the body, good accuracy, and can better distinguish the different components of the stone,make the qualitative judgment, in order to provide evidence for clinical treatment. In the group of patients with oxalate stones up to about 90%,different from previous research,analysis may be related to regional,national,differ-ences in diet,pending further study.%目的:探讨双源CT对泌尿系结石成分定性的诊断价值,旨在提高临床诊断的正确率,改善患者的临床疗效。方法选取我院2014年8~12月间因腹痛怀疑

  15. Dual Sourcing Decisions under Exchange Rate and Supply Risks%面临汇率和供应风险的双渠道采购决策研究

    Institute of Scientific and Technical Information of China (English)

    温源; 肖勇波

    2013-01-01

    多渠道采购是制造商降低采购风险的有效手段之一.本文考虑一个制造商向两个供应商进行联合采购的最优决策问题.其中本土(国内)供应商价格稳定,但供应不可靠;母国(国外)供应商供应可靠,但实际价格受汇率波动影响.本文研究了制造商在风险厌恶情形下的最优联合采购决策,并与风险中性情形进行了比较.研究表明,风险中性制造商只会向一个供应商采购;而风险厌恶制造商的采购决策会受到供应可靠性、汇率的波动以及两者相关关系的影响.具体来说,当产品合格率和汇率相对独立时,风险厌恶的制造商倾向于单渠道采购;当合格率和汇率相关时则可能选择双渠道采购以分散风险.数值实验表明,双渠道采购可以有效降低制造商的损失风险.%Dual sourcing is an effective way for procurement risk diversification.This paper considers a risk-averse manufacturer that faces two sourcing alternatives:a domestic supplier that is unreliable,and a supplier in the manufacturer's home country that is fully reliable,and actual price of components is affected by fluctuated exchange rate.The joint optimal procurement decision for the risk-averse manufacturer is developed and is compared with the situation of risk neutrality.Modeling analysis shows that the risk-neutral manufacturer only places order to single supplier.The risk-averse manufacturer,however,is influenced by the fluctuations of both exchange rate and supply and their correlation.When the reliability and exchange rate correlates,it may procure from both sources so as to reduce risk.Results from numerical study show that dual sourcing can lower the loss risk.

  16. Correlation between blood adenosine metabolism and sleep in humans.

    Science.gov (United States)

    Díaz-Muñoz, M; Hernández-Muñoz, R; Suárez, J; Vidrio, S; Yááñez, L; Aguilar-Roblero, R; Rosenthal, L; Villalobos, L; Fernández-Cancino, F; Drucker-Colín, R; Chagoya De Sanchez, V

    1999-01-01

    Blood adenosine metabolism, including metabolites and metabolizing enzymes, was studied during the sleep period in human volunteers. Searching for significant correlations among biochemical parameters found: adenosine with state 1 of slow-wave sleep (SWS); activity of 5'-nucleotidase with state 2 of SWS; inosine and AMP with state 3-4 of SWS; and activity of 5'-nucleotidase and lactate with REM sleep. The correlations were detected in all of the subjects that presented normal hypnograms, but not in those who had fragmented sleep the night of the experiment. The data demonstrate that it is possible to obtain information of complex brain operations such as sleep by measuring biochemical parameters in blood. The results strengthen the notion of a role played by adenosine, its metabolites and metabolizing enzymes, during each of the stages that constitute the sleep process in humans.

  17. Tween 20-stabilized gold nanoparticles combined with adenosine triphosphate-BODIPY conjugates for the fluorescence detection of adenosine with more than 1000-fold selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Szu-Ying; Shih, Ya-Chen [Department of Chemistry, National Sun Yat-sen University, Taiwan (China); Tseng, Wei-Lung, E-mail: tsengwl@mail.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Taiwan (China); School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Taiwan (China); Center for Nanoscience and Nanotechnology, National Sun Yat-sen University, Taiwan (China); Center for Stem Cell Research, Kaohsiung Medical University, Taiwan (China)

    2015-02-01

    Graphical abstract: A simple, enzyme-free, label-free, sensitive and selective system was developed for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles as an efficient quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate and as a recognition element for adenosine. - Highlights: • The proposed method can detect adenosine with more than 1000-fold selectivity. • The analysis of adenosine is rapid (∼6 min) using the proposed method. • This method provided better sensitivity for adenosine as compared to aptamer-based sensors. • This method can be applied for the determination of adenosine in urine. - Abstract: This study describes the development of a simple, enzyme-free, label-free, sensitive, and selective system for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles (Tween 20-AuNPs) as an efficient fluorescence quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate (BODIPY-ATP) and as a recognition element for adenosine. BODIPY-ATP can interact with Tween 20-AuNPs through the coordination between the adenine group of BODIPY-ATP and Au atoms on the NP surface, thereby causing the fluorescence quenching of BODIPY-ATP through the nanometal surface energy transfer (NSET) effect. When adenosine attaches to the NP surface, the attached adenosine exhibits additional electrostatic attraction to BODIPY-ATP. As a result, the presence of adenosine enhances the efficiency of AuNPs in fluorescence quenching of BODIPY-ATP. The AuNP-induced fluorescence quenching of BODIPY-ATP progressively increased with an increase in the concentration of adenosine; the detection limit at a signal-to-noise ratio of 3 for adenosine was determined to be 60 nM. The selectivity of the proposed system was more than 1000-fold for adenosine over any adenosine analogs and other nucleotides. The proposed system combined with a phenylboronic acid-containing column was successfully applied to the

  18. Development of coronary vasospasm during adenosine-stress myocardial perfusion CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Jeong Gu; Choi, Seong Hoon; Kang, Byeong Seong; Bang, Min Aeo; Kwon, Woon Jeong [Dept. of Radiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan (Korea, Republic of)

    2015-06-15

    Adenosine is a short-acting coronary vasodilator, and it is widely used during pharmacological stress myocardial perfusion imaging. It has a well-established safety profile, and most of its side effects are known to be mild and transient. Until now, coronary vasospasm has been rarely reported as a side effect of adenosine during or after adenosine stress test. This study reports a case of coronary vasospasm which was documented on stress myocardial perfusion CT imaging during adenosine stress test.

  19. Comparison of Diagnosis Value of MRI and Dual-Source CT in Knee-Joint Trauma%磁共振和双源CT在膝关节外伤中的诊断价值对比

    Institute of Scientific and Technical Information of China (English)

    杨进军; 何桂茹; 班允清

    2015-01-01

    目的 对磁共振和双源CT在膝关节外伤中的诊断价值进行对比分析. 方法 整群选取该院2011年1月—2014年5月间收治的141例膝关节外伤患者的影像资料进行回顾性分析,以手术结果作为参照,对比两种检测方法的诊断准确率.结果 双源CT与MRI对膝关节外伤的检出率分别为70.9%与94.3%,组间比较MRI的检出率显著高于CT,差异具有统计学意义(P<0.05). 以手术结果作为参照,对不同类型膝关节外伤的诊断准确率进行比较显示,MRI对于骨质损伤、韧带损伤、半月板损伤及关节囊积液的显示情况均优于双源CT,差异有统计学意义(P<0.05). 结论 MRI对于膝关节外伤的各项检出率均高于双源CT. 术前通过MRI全面检查掌握膝关节损伤情况,有助于帮忙骨科医生合理制定手术预案.%Objective To analyze and compare the diagnosis value of MRI and dual-source CT in knee-joint trauma. Methods The images about 141 patients with knee-joint trauma treated from January 2011 to May 2014 in our hospital were retrospectively analyzed. According to the operation results, the detection accuracy based on two methods was compared. Results The detection rate of knee-joint trauma based on dual-source CT and MRI was 70.9% and 94.3%. The rate of MRI was higher than that of CT (P<0.05); according to comparison results of detection accuracy for different types of knee-joint trauma, the imaging of injury of bone, ligamentous injury, meniscus injury and drainage of articular capsule based on MRI was significantly better than that of du-al-source CT (P<0.05). Conclusion The detection rate of knee-joint trauma based on MRI is higher than that of dual-source CT. Be-fore surgery, the complete inspection of knee-joint injury based on MRI is good for the orthopedists to make the reasonable opera-tion planning.

  20. Compare and Research the Radiation dose and Image Quality on Dual Energy Dual Source Spiral CT Pulmonary Artery Imaging%双源双能量螺旋CT肺动脉成像辐射剂量与图像质量的对比研究

    Institute of Scientific and Technical Information of China (English)

    张筱双

    2015-01-01

    Objective To compare the difference of the radiation dose and image quality on dual energy dual source spiral CT pulmonary artery imaging.Methods 80 cases of pulmonary embolism patients in our hospital were selected as the research object. All patients were willing to accept CTPA examination, 40 cases in each group. A group used tube voltage 80/Sn140KV check, B group used tube voltage 100/Sn140KV examination, compared two groups’ pulmonary artery, pulmonary artery, the dorsal fat CT value, other indicators and CT image treatment subjective evaluation, calculation of signal to noise ratio (SNR), contrast to noise ratio (CNR) and effective dose (ED).Results The average CT value of A group’s pulmonary artery, mean CNR index were signiifcantly higher than those of group B(P<0.05), subjective CT image quality evaluation results show score were not signiifcantly different between A group and B group, but ed level of group A was signiifcantly lower than that of group B(P<0.05).Conclusion Dual source dual energy CT pulmonary artery imaging using scanning 80/Sn140 kV has high value in the diagnosis of CT images at the same time, and can greatly reduce the radiation dose during examination, which has clinical application and popularization value.%目的:对比第二代双源双能量螺旋CT肺动脉成像(CTPA)不同辐射剂量下CT图像质量的差异性。方法筛选我院收治的肺栓塞患者80例,作为研究对象。所有患者均自愿接受CTPA检查,每组40例,其中A组管电压80/Sn140KV检查,B组管电压100/Sn140KV检查,比较两组患者肺动脉主干、肺动脉段、背部脂肪CT值等指标,并对CT影像治疗进行主观评分,计算信噪比(SNR)、对比噪声比(CNR)、有效剂量(ED)等。结果 A组患者肺动脉平均CT值、平均CNR指标明显高于B组(P<0.05),主观CT影像质量评价结果显示A组与B组评分无显著差异,但A组ED水平明显低于B组(P<0.05)。结论

  1. DMPD: Shaping of monocyte and macrophage function by adenosine receptors. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17056121 Shaping of monocyte and macrophage function by adenosine receptors. Hasko ...tml) (.csml) Show Shaping of monocyte and macrophage function by adenosine receptors. PubmedID 17056121 Titl...e Shaping of monocyte and macrophage function by adenosine receptors. Authors Has

  2. Adenosine A(3) receptor-induced CCL2 synthesis in cultured mouse astrocytes

    NARCIS (Netherlands)

    Wittendorp, MC; Boddeke, HWGM; Biber, K

    2004-01-01

    During neuropathological conditions, high concentrations of adenosine are released, stimulating adenosine receptors in neurons and glial cells. It has recently been shown that stimulation of adenosine receptors in glial cells induces the release of neuroprotective substances such as NGF, S-100beta,

  3. The role of glial adenosine receptors in neural resilience and the neurobiology of mood disorders

    NARCIS (Netherlands)

    Calker, D; Biber, K

    2005-01-01

    Adenosine receptors were classified into A(1)- and A(2)-receptors in the laboratory of Bernd Hamprecht more than 25 years ago. Adenosine receptors are instrumental to the neurotrophic effects of glia cells. Both microglia and astrocytes release after stimulation via adenosine receptors factors that

  4. Differential diagnosis of osteoblastic metastases from bone islands in patients with lung cancer by single-source dual-energy CT: Advantages of spectral CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yue, E-mail: dyy1026@sina.com [Department of Radiology, The First Affiliated Hospital of Dalian Medical University, LiaoNing 116011 (China); Zheng, Shaowei, E-mail: chouxiong@sohu.com [Department of Radiology, The First Affiliated Hospital of Dalian Medical University, LiaoNing 116011 (China); Machida, Haruhiko, E-mail: machira@dnh.twmu.ac.jp [Department of Radiology, Tokyo Women' s Medical University Medical Center East, Tokyo 116-8567 (Japan); Wang, Bing, E-mail: wangbing19831003@163.com [Department of Radiology, The First Affiliated Hospital of Dalian Medical University, LiaoNing 116011 (China); Liu, Ailian, E-mail: dmu_liuailian@126.com [Department of Radiology, The First Affiliated Hospital of Dalian Medical University, LiaoNing 116011 (China); Liu, Yijun, E-mail: yijunliu1965@126.com [Department of Radiology, The First Affiliated Hospital of Dalian Medical University, LiaoNing 116011 (China); Zhang, Xin, E-mail: zhhw2000@126.com [Department of Nuclear Medicine, The First Affiliated Hospital of Dalian Medical University, Liaoning 116011 (China)

    2015-05-15

    Highlights: • Spectral CT were useful for the follow-up of spinal lesions in patients with lung cancer. • Spectral CT were useful for more accurate differential diagnosis of OBMs and BIs. • 110 keV virtual monochromatic images were the optimal for providing this differentiation. - Abstract: Objectives: To evaluate the diagnostic efficacy of spectral CT for the differentiation of osteoblastic metastases (OBMs) from bone islands (BIs) in patients with lung cancer. Methods: In 94 patients with lung cancer who underwent spectral CT, focal hyperdense lesions in vertebral bodies were diagnosed as OBMs or BIs. Regions of interest were placed within each lesion to measure the mean CT value and its standard deviation (SD) on polychromatic single-energy CT (SECT) at 140 kVp and dual-energy virtual monochromatic spectral (VMS) images. The mean bone (D{sub bone(wa)}) and water densities (D{sub wa(bone)}) of each lesion were also measured. The slope (k) of the spectral curve was calculated. Independent-sample t-test was used to compare those values between OBMs and BIs. Receiver operator characteristic analysis was performed to compare the area under curve (AUC) for the differentiation of OBMs from BIs. Results: A total of 79 OBMs and 43 BIs were confirmed. The CT and SD values on SECT at 140 kVp and VMS images at 50–130 keV, k value, and D{sub bone(wa)} for OBMs were significantly lower than for BIs; D{sub wa(bone)} was significantly higher for OBMs than for BIs (p < 0.05 for all). The AUC for the SD value at 110 keV was the highest among those parameters. The optimal cut-off value for this differentiation was 68.6 HU for the SD value on VMS images at 110 keV with sensitivity of 93.0% and specificity of 93.3%. Conclusion: Spectral CT is helpful for the differentiation of OBMs from BIs in patients with lung cancer, particularly using SD of the CT value on high-energy VMS images.

  5. 双源CT双能量碘图对急性坏死性胰腺炎影像的诊断价值%The Value of Dual-source Dual-energy CT with Iodine Overlay in the Diagnosis of Acute Necrotizing Pancreatitis

    Institute of Scientific and Technical Information of China (English)

    袁元; 黄子星; 李真林; 宋彬; 邓莉萍

    2012-01-01

    Objective To investigate the clinical value of dual-source computed tomography dual-energy Iodine overlay technique in the imaging diagnosis of acute necrotizing pancreatitis. Methods The imaging data were retrospectively analyzed in 67 cases of acute necrotizing pancreatitis underwent contrast-enhanced dual-source dual-energy CT in portal venous phase. The CT imaging parameters, including the difference of CT value between pancreatic parenchyma and necrotic lesion, contrast-to-noise ratio of pancreatic parenchyma-to-necrosis, area of pancreatic necrosis and score of subjective diagnosis, were measured and assessed on CT images of 80 kV, 140 kV, weighted-average 120 kV as well as Iodine overlay. Results The differences of CT value between pancreatic parenchyma and necrosis in the images of 80 kV, 140 kV, weighted-average 120 kV and Iodine overlay were (67. 40 ±20.82) HU,(42. 87±14. 99) HU, (48. 69±15. 82) HU, (33. 01 ± 10. 26) HU, respectively;contrast-to-noise ratios of pancreatic parenchyma-to-necrosis of each group were 8. 36 ± 3. 58, 5. 85±2. 65, 7. 68±3. 51, 10. 60± 4. 34;area of pancreatic necrosis of each group was (3. 78 ±2. 68) cm2, (3.28 ± 2.59) cm2, (3. 37±2. 46) cm2, (2. 42 ± 1. 98) cm2 ;the score of subjective diagnosis of each group was 3. 88 ±0. 33, 3. 31 ± 0. 80, 3. 58 ±0. 66, 2. 81 ± 0. 76, respectively. The four indexes in the images of Iodine overlay were significantly different from those of another three groups (P<0. 05). Contrast-to-noise ratio of pancreatic parenchyma-to-necrosis in the images of Iodine overlay was significantly higher than that of another three groups, while the difference of CT value, area of pancreatic necrosis and score of subjective diagnosis were lower. Conclusion Dual-source CT dual-energy Iodine overlay is not helpful to improve subjective judgment in the diagnosis of pancreatic necrosis, but contributes to the display of hypoperfusion area around the necrosis.%目的 初步探讨双源CT双能量碘

  6. Searching Inhibitors of Adenosine Kinase by Simulation Methods

    Institute of Scientific and Technical Information of China (English)

    ZHU Rui-Xin; ZHANG Xing-Long; DONG Xi-Cheng; CHEN Min-Bo

    2006-01-01

    Searching new inhibitors of adenosine kinase (AK) is still drawing attention of experimental scientists. A better and solid model is here proposed by means of simulation methods from different ways, the direct analysis of receptor itself, the conventional 3D-QSAR methods and the integration of docking method and the conventional QSAR analysis.

  7. 21 CFR 864.7040 - Adenosine triphosphate release assay.

    Science.gov (United States)

    2010-04-01

    ... device that measures the release of adenosine triphosphate (ATP) from platelets following aggregation. This measurement is made on platelet-rich plasma using a photometer and a luminescent firefly extract. Simultaneous measurements of platelet aggregation and ATP release are used to evaluate platelet...

  8. No role of interstitial adenosine in insulin-mediated vasodilation

    DEFF Research Database (Denmark)

    Dela, F; Stallknecht, B

    1999-01-01

    The mechanisms behind the vasodilatory effect of insulin are not fully understood, but nitric oxide plays an important role. We have investigated the possibility that insulin mediates vasodilatation in the human skeletal muscle via an increase in extracellular adenosine concentrations. In eight h...

  9. CD39/adenosine pathway is involved in AIDS progression.

    Directory of Open Access Journals (Sweden)

    Maria Nikolova

    2011-07-01

    Full Text Available HIV-1 infection is characterized by a chronic activation of the immune system and suppressed function of T lymphocytes. Regulatory CD4+ CD25(high FoxP3+CD127(low T cells (Treg play a key role in both conditions. Here, we show that HIV-1 positive patients have a significant increase of Treg-associated expression of CD39/ENTPD1, an ectoenzyme which in concert with CD73 generates adenosine. We show in vitro that the CD39/adenosine axis is involved in Treg suppression in HIV infection. Treg inhibitory effects are relieved by CD39 down modulation and are reproduced by an adenosine-agonist in accordance with a higher expression of the adenosine A2A receptor on patients' T cells. Notably, the expansion of the Treg CD39+ correlates with the level of immune activation and lower CD4+ counts in HIV-1 infected patients. Finally, in a genetic association study performed in three different cohorts, we identified a CD39 gene polymorphism that was associated with down-modulated CD39 expression and a slower progression to AIDS.

  10. Role of dual source CT perfusion imaging in the diagnosis of early radiation-induced lung injury%双源 CT灌注成像诊断早期放射性肺损伤的应用价值

    Institute of Scientific and Technical Information of China (English)

    潘利福; 邝平定

    2015-01-01

    Objective To examine the role of dual source CT perfusion imaging for early diagnosis of radiation -induced lung injury and to obtain scientific knowledge for early diagnosis of radiation induced lung injury .Method The level of dual source CT perfusion imaging perfusion values of the radiation-induced lung injury patients ( the experimental group , n=45 ) and that of the patients with no radiation-induced lung injury (the control group, n=45) was monitored.Meanwhile, the patients with radiation-induced lung injury were subjected to conventional CT examination .The sensitivity and accuracy of the two detection methods were then compared .Findings The values of lung tissue blood flow ( rrBF ) , relative blood volume ( rrBV) , relative blood capillary permeability ( chip) of the experimental group were significantly higher than those of the control group (P0.05).41 of the 45 patients of the experimental group were diagnosed as cases of radioactive lung injury.The diagnostic sensitivity and specificity were 91.1% and 97.78% respectively, which were significantly higher than those of the conventional CT technology (P<0.01).Conclusion Dual source CT perfusion imaging can display the changes after radiotherapy of lung hemodynamics and display early perfusion abnormalities in patients with radiation -induced lung injury.It can serve as an effective tool for early detection of radiation-induced lung injury .%目的:探讨双源CT灌注成像早期诊断放射性肺损伤的应用效果,为放射性肺损伤早期诊断提供依据。方法观察放射性肺损伤患者45例(观察组)和未发生放射性肺损伤患者45例(对照组)的双源CT灌注成像灌注值的水平,同时对放射性肺损伤患者采用常规的CT检查,比较两种检测方法的灵敏度和准确度。结果观察组肺组织相对血流量(rrBF)、相对血容量(rrBV)、相对毛细血管通透性(rrPS)均显著高于对照组(P<0.05);观察组45

  11. Heat pump using dual heat sources of air and water. Performance with heat sources arranged in parallel; Mizu kuki ryonetsugen heat pump no kenkyu. Netsugen heiretsu unten ni okeru seino

    Energy Technology Data Exchange (ETDEWEB)

    Ito, S.; Miura, N.; Sato, S. [Kanagawa Institute of Technology, Kanagawa (Japan); Uchikawa, Y.; Hamada, K. [Kubota Corp., Osaka (Japan)

    1996-10-27

    A heat pump system using water and air as heat sources was built and evaluated for its performance. In this system, evaporators may be operated singly or as connected in parallel or series, and, for each case, the quantity of heat acquired may be measured and system performance may be quantitatively evaluated. The findings follow. When the two heat sources are equal in temperature in the single-evaporator operation, the evaporation temperature is about 7{degree}C higher on the water side than on the air side, and the performance coefficient is about 0.7 higher. When the air heat source temperature is 25{degree}C in the parallel operation, like quantities of heat are obtained from both heat sources, and collection of heat from the water increases with a decrease in the air heat source temperature but, with an increase, collection from the air increases. When the air heat source temperature decreases, the evaporation temperature decreases in the single-evaporator working on the air and in the parallel operation but it levels off in the single-evaporator working on the water alone. When the water heat source temperature decreases, evaporation temperature drop is sharper in the single-evaporator working on the water than in the parallel operation, which suggests the transfer from the parallel operation to the single-evaporator working on the air. In the single-evaporator operation on the water heat source, the evaporation temperature linearly decreases with an increase in superheating. 1 ref., 10 figs.

  12. Compact and tunable mid-infrared source based on a 2μm dual-wavelength KTiOPO4 intracavity optical parametric oscillator

    Institute of Scientific and Technical Information of China (English)

    Geng You-Fu; Tan Xiao-Ling; Li Xue-Jin; Yao Jian-Quan

    2010-01-01

    Using a double resonant KTiOPO4(KTP)intracavity optical parametric oscillator operating at degenerated point of 2 μm,we demonstrate a unique mid-infrared source based on difference frequency generation in GaSe crystal.The output tuning range is 8.42-19.52 μm,and a peak power of 834 W for type-Ⅰ phase matching scheme and 730 W for type-Ⅱ phase matching scheme are achieved.Experimental results show that this oscillator is a good alternative to the generator of a compact and tabletop mid-infrared radiation with a widely tunable range.

  13. Striatal adenosine-cannabinoid receptor interactions in rats over-expressing adenosine A2A receptors.

    Science.gov (United States)

    Chiodi, Valentina; Ferrante, Antonella; Ferraro, Luca; Potenza, Rosa Luisa; Armida, Monica; Beggiato, Sarah; Pèzzola, Antonella; Bader, Michael; Fuxe, Kjell; Popoli, Patrizia; Domenici, Maria Rosaria

    2016-03-01

    Adenosine A2A receptors (A2 A Rs) and cannabinoid CB1 receptors (CB1 Rs) are highly expressed in the striatum, where they functionally interact and form A2A /CB1 heteroreceptor complexes. We investigated the effects of CB1 R stimulation in a transgenic rat strain over-expressing A2 A Rs under the control of the neural-specific enolase promoter (NSEA2A rats) and in age-matched wild-type (WT) animals. The effects of the CB1 R agonist WIN 55,212-2 (WIN) were significantly lower in NSEA2A rats than in WT animals, as demonstrated by i) electrophysiological recordings of synaptic transmission in corticostriatal slices; ii) the measurement of glutamate outflow from striatal synaptosomes and iii) in vivo experiments on locomotor activity. Moreover, while the effects of WIN were modulated by both A2 A R agonist (CGS 21680) and antagonists (ZM 241385, KW-6002 and SCH-442416) in WT animals, the A2 A R antagonists failed to influence WIN-mediated effects in NSEA2A rats. The present results demonstrate that in rats with genetic neuronal over-expression of A2 A Rs, the effects mediated by CB1 R activation in the striatum are significantly reduced, suggesting a change in the stoichiometry of A2A and CB1 receptors and providing a strategy to dissect the involvement of A2 A R forming or not forming heteromers in the modulation of striatal functions. These findings add additional evidence for the existence of an interaction between striatal A2 A Rs and CB1 Rs, playing a fundamental role in the regulation of striatal functions. We studied A2A -CB1 receptor interaction in transgenic rats over-expressing adenosine A2A receptors under the control of the neuron-specific enolase promoter (NSEA2A ). In these rats, we demonstrated a reduced effect of the CB1 receptor agonist WIN 55,212-2 in the modulation of corticostriatal synaptic transmission and locomotor activity, while CB1 receptor expression level did not change with respect to WT rats. A reduction in the expression of A2A -CB1

  14. Utility of virtual endoscopy in coronary dual-source CT angiography: initial experience%仿真内镜用于双源CT冠状动脉成像的初步经验

    Institute of Scientific and Technical Information of China (English)

    何卫红; 陈伟; 周晖

    2011-01-01

    目的 初步探讨双源CT冠状动脉成像时利用仿真内镜诊断冠状动脉疾病的潜在价值.方法 使用Fly-through软件对40例双源CT冠状动脉成像病例行仿真内镜观察,并与CT冠状动脉成像常规方法和传统冠状动脉造影术进行比较.结果 40例患者共120支冠状动脉中,92%(110/120)的冠状动脉可行仿真内镜成像;仿真内镜判断有意义的冠状动脉狭窄正确率为85%( 41/48);常规CT冠状动脉成像不能判断的9处严重钙化,仿真内镜显示为显著或高度狭窄;4枚冠状动脉支架内和3支桥血管仿真内镜显示通畅.结论 仿真内镜可立体显示正常和病变冠状动脉腔内情况,是CT冠状动脉成像后处理方法的的重要补充.%[Objective] To explore the potential clinical value of virtual endoscopy in detecting coronary artery lesions. [Methods] Forty patients underwent dual-source CT coronary angiography. Virtual endoscopies were simulated in 120 coronary arteries using the Fly-through software, with routine imaging post-processing methods of CT coronary angiography and conventional coronary angiography as the reference standard. [Results] Virtual endo- scopies of 92% (110/120) major coronary artery were successfully performed with good image quality, and the accuracy of virtual coronary angioscopy was 85% (41/48) for detecting hemodynamically significant stenoses confirmed by conventional coronary angiography. Using virtual coronary angioscopy, 9 severe calcified coronary arteries were identified as significant or severe stenoses, while unable to estimate by routine CT coronary angiography. Virtual endoscopies of intracoronary stents (n=4) or bypass grafts (n=4) were patency. [Conclusions] Endoscopy of coronary arteries using dual-source CT allows comprehensive 3-dimensional delineation of the vessel lumen, and can be used as an important complement to the routine post-processing methods of CT coronary angiography in some cases.

  15. 双源CT脑血管成像在颅内动脉瘤早期诊断中的应用%Application of dual-source CT angiography in the early diagnosis of intracranial aneurysms

    Institute of Scientific and Technical Information of China (English)

    耿云平

    2014-01-01

    目的 通过分析蛛网膜下腔出血(SAH)患者早期双源CT脑血管造影(CTA)的结果,探讨双源CT在颅内动脉瘤早期诊断中的应用.方法 对78例蛛网膜下腔出血患者行CTA检查,通过外科开颅夹闭术或DSA介入栓塞术等治疗.结果 78例CTA检查阳性70例,可疑6例,阴性2例.对可疑6例及阴性2例行DSA复查,结果确诊动脉瘤6例,阴性2例,假阳性及假阴性各2例.结论 CTA是一种快速、无创、可靠、简便的方法,能早期诊断动脉瘤,并能基本提供临床医生开颅行动脉瘤夹闭手术所需的影像学资料;对小动脉瘤的诊断尚需DSA检查进一步证实.%Objective By analyzing the early dual-source CT angiography of patients with subarachnoid hemorrhage (SAH),to study the application of dual-source CT in the early diagnosis of intracranial aneurysms.Methods Seventy-eight cases of subarachnoid hemorrhage underwent CTA,by the surgical clipping treatment or DSA intervention.Results Among the 78 cases,CTA positive in 70 cases,suspicious in 6 cases,2 cases were negative.The 6 suspicious patients and 2 negative patients underwent DSA review,6 cases were aneurysm,2 cases were negative,false positive and false negative cases were all 2 cases.Conclusions CTA is a fast,noninvasive,simple,reliable method,it can diagnose aneurysm earlier,basically it can provide the imaging datas of the surgical clipping operation required; the diagnosis of small aneurysms still need further confirmation by DSA examination.

  16. Adenosine A2B receptor-mediated leukemia inhibitory factor release from astrocytes protects cortical neurons against excitotoxicity

    Directory of Open Access Journals (Sweden)

    Moidunny Shamsudheen

    2012-08-01

    Full Text Available Abstract Background Neuroprotective and neurotrophic properties of leukemia inhibitory factor (LIF have been widely reported. In the central nervous system (CNS, astrocytes are the major source for LIF, expression of which is enhanced following disturbances leading to neuronal damage. How astrocytic LIF expression is regulated, however, has remained an unanswered question. Since neuronal stress is associated with production of extracellular adenosine, we investigated whether LIF expression in astrocytes was mediated through adenosine receptor signaling. Methods Mouse cortical neuronal and astrocyte cultures from wild-type and adenosine A2B receptor knock-out animals, as well as adenosine receptor agonists/antagonists and various enzymatic inhibitors, were used to study LIF expression and release in astrocytes. When needed, a one-way analysis of variance (ANOVA followed by Bonferroni post-hoc test was used for statistical analysis. Results We show here that glutamate-stressed cortical neurons induce LIF expression through activation of adenosine A2B receptor subtype in cultured astrocytes and require signaling of protein kinase C (PKC, mitogen-activated protein kinases (MAPKs: p38 and ERK1/2, and the nuclear transcription factor (NF-κB. Moreover, LIF concentration in the supernatant in response to 5′-N-ethylcarboxamide (NECA stimulation was directly correlated to de novo protein synthesis, suggesting that LIF release did not occur through a regulated release pathway. Immunocytochemistry experiments show that LIF-containing vesicles co-localize with clathrin and Rab11, but not with pHogrin, Chromogranin (CgA and CgB, suggesting that LIF might be secreted through recycling endosomes. We further show that pre-treatment with supernatants from NECA-treated astrocytes increased survival of cultured cortical neurons against glutamate, which was absent when the supernatants were pre-treated with an anti-LIF neutralizing antibody. Conclusions

  17. Feed-Forward Inhibition of CD73 and Upregulation of Adenosine Deaminase Contribute to the Loss of Adenosine Neuromodulation in Postinflammatory Ileitis

    Directory of Open Access Journals (Sweden)

    Cátia Vieira

    2014-01-01

    Full Text Available Purinergic signalling is remarkably plastic during gastrointestinal inflammation. Thus, selective drugs targeting the “purinome” may be helpful for inflammatory gastrointestinal diseases. The myenteric neuromuscular transmission of healthy individuals is fine-tuned and controlled by adenosine acting on A2A excitatory receptors. Here, we investigated the neuromodulatory role of adenosine in TNBS-inflamed longitudinal muscle-myenteric plexus of the rat ileum. Seven-day postinflammation ileitis lacks adenosine neuromodulation, which may contribute to acceleration of gastrointestinal transit. The loss of adenosine neuromodulation results from deficient accumulation of the nucleoside at the myenteric synapse despite the fact that the increases in ATP release were observed. Disparity between ATP outflow and adenosine deficit in postinflammatory ileitis is ascribed to feed-forward inhibition of ecto-5′-nucleotidase/CD73 by high extracellular ATP and/or ADP. Redistribution of NTPDase2, but not of NTPDase3, from ganglion cell bodies to myenteric nerve terminals leads to preferential ADP accumulation from released ATP, thus contributing to the prolonged inhibition of muscle-bound ecto-5′-nucleotidase/CD73 and to the delay of adenosine formation at the inflamed neuromuscular synapse. On the other hand, depression of endogenous adenosine accumulation may also occur due to enhancement of adenosine deaminase activity. Both membrane-bound and soluble forms of ecto-5′-nucleotidase/CD73 and adenosine deaminase were detected in the inflamed myenteric plexus. These findings provide novel therapeutic targets for inflammatory gut motility disorders.

  18. Fringe formation in dual-hologram interferometry

    Science.gov (United States)

    Burner, A. W.

    1990-01-01

    Reference-fringe formation in nondiffuse dual-hologram interferometry is described by combining a first-order geometrical hologram treatment with interference fringes generated by two point sources. The first-order imaging relationships can be used to describe reference-fringe patterns for the geometry of the dual-hologram interferometry. The process can be completed without adjusting the two holograms when the reconstructing wavelength is less than the exposing wavelength, and the process is found to facilitate basic intereferometer adjustments.

  19. Modulatory effect of iron chelators on adenosine deaminase activity and gene expression in Trichomonas vaginalis.

    Science.gov (United States)

    Primon-Barros, Muriel; Rigo, Graziela Vargas; Frasson, Amanda Piccoli; Santos, Odelta dos; Smiderle, Lisiane; Almeida, Silvana; Macedo, Alexandre José; Tasca, Tiana

    2015-11-01

    Trichomonas vaginalis is a flagellate protozoan that parasitises the urogenital human tract and causes trichomoniasis. During the infection, the acquisition of nutrients, such as iron and purine and pyrimidine nucleosides, is essential for the survival of the parasite. The enzymes for purinergic signalling, including adenosine deaminase (ADA), which degrades adenosine to inosine, have been characterised in T. vaginalis. In the evaluation of the ADA profile in different T. vaginalis isolates treated with different iron sources or with limited iron availability, a decrease in activity and an increase in ADA gene expression after iron limitation by 2,2-bipyridyl and ferrozine chelators were observed. This supported the hypothesis that iron can modulate the activity of the enzymes involved in purinergic signalling. Under bovine serum limitation conditions, no significant differences were observed. The results obtained in this study allow for the assessment of important aspects of ADA and contribute to a better understanding of the purinergic system in T. vaginalis and the role of iron in establishing infection and parasite survival.

  20. Small-Animal PET Study of Adenosine A(1) Receptors in Rat Brain : Blocking Receptors and Raising Extracellular Adenosine

    NARCIS (Netherlands)

    Paul, Soumen; Khanapur, Shivashankar; Rybczynska, Anna A.; Kwizera, Chantal; Sijbesma, Jurgen W. A.; Ishiwata, Kiichi; Willemsen, Antoon T. M.; Elsinga, Philip H.; Dierckx, Rudi A. J. O.; van Waarde, Aren

    2011-01-01

    Activation of adenosine A(1) receptors (A(1)R) in the brain causes sedation, reduces anxiety, inhibits seizures, and promotes neuroprotection. Cerebral A(1)R can be visualized using 8-dicyclopropylmethyl-1-C-11-methyl-3-propyl-xanthine (C-11-MPDX) and PET. This study aims to test whether C-11-MPDX c

  1. The Rickettsia prowazekii invasion gene homolog (invA) encodes a Nudix hydrolase active on adenosine (5')-pentaphospho-(5')-adenosine.

    Science.gov (United States)

    Gaywee, Jariyanart; Xu, WenLian; Radulovic, Suzana; Bessman, Maurice J; Azad, Abdu F

    2002-03-01

    The genomic sequence of Rickettsia prowazekii, the obligate intracellular bacterium responsible for epidemic typhus, reveals an uncharacterized invasion gene homolog (invA). The deduced protein of 18,752 Da contains a Nudix signature, the specific motif found in the Nudix hydrolase family. To characterize the function of InvA, the gene was cloned and overexpressed in Escherichia coli. The expressed protein was purified to near homogeneity and subsequently tested for its enzymatic activity against a series of nucleoside diphosphate derivatives. The purified InvA exhibits hydrolytic activity toward dinucleoside oligophosphates (Np(n)N; n > or = 5), a group of cellular signaling molecules. At optimal pH 8.5, the enzyme actively degrades adenosine (5')-pentaphospho-(5')-adenosine into ATP and ADP with a K(m) of 0.1 mM and k(cat) of 1.9 s(-1). Guanosine (5')-pentaphospho-(5')-guanosine and adenosine-(5')-hexaphospho (5')-adenosine are also substrates. Similar to other Nudix hydrolases, InvA requires a divalent metal cation, Mg(2+) or Zn(2+), for optimal activity. These data suggest that the rickettsial invasion protein likely plays a role in controlling the concentration of stress-induced dinucleoside oligophosphates following bacterial invasion.

  2. Dual solutions for unsteady mixed convection flow of MHD micropolar fluid over a stretching/shrinking sheet with non-uniform heat source/sink

    Directory of Open Access Journals (Sweden)

    N. Sandeep

    2015-12-01

    Full Text Available The aim of the present study is to investigate the influence of non-uniform heat source/sink, mass transfer and chemical reaction on an unsteady mixed convection boundary layer flow of a magneto-micropolar fluid past a stretching/shrinking sheet in the presence of viscous dissipation and suction/injection. The governing equations of the flow, heat and mass transfer are transformed into system of nonlinear ordinary differential equations by using similarity transformation and then solved numerically using Shooting technique with Matlab Package. The influence of non-dimensional governing parameters on velocity, microrotation, temperature and concentration profiles are discussed and presented with the help of their graphical representations. Also, friction factor, heat and mass transfer rates have been computed and presented through tables. Under some special conditions, present results are compared with the existed results to check the accuracy and validity of the present study. An excellent agreement is observed with the existed results.

  3. Asymmetric Dual Axis Energy Recovery Linac for Ultra-High Flux sources of coherent X-ray/THz radiation: Investigations Towards its Ultimate Performance

    CERN Document Server

    Ainsworth, R; Konoplev, I V; Seryi, A

    2015-01-01

    Truly compact and high current, efficient particle accelerators are required for sources of coherent high brightness and intensity THz and X-Ray radiation to be accepted by university or industrial R&D laboratories. The demand for compactness and efficiency can be satisfied by superconducting RF energy recovery linear accelerators (SRF ERL) allowing effectively minimising the footprint and maximising the efficiency of the system. However such set-ups are affected by regenerative beam-break up (BBU) instabilities which limit the beam current and may terminate the beam transport as well as energy recuperation. In this paper we suggest and discuss a SRF ERL with asymmetric configuration of accelerating and decelerating cavities resonantly coupled. In this model of SRF ERL we propose an electron bunch passing through accelerating and decelerating cavities each once and we show that in this case the regenerative BBU instability can be minimised allowing high currents to be achieved. We study the BBU start curr...

  4. Fast-scan Cyclic Voltammetry for the Characterization of Rapid Adenosine Release.

    Science.gov (United States)

    Nguyen, Michael D; Venton, B Jill

    2015-01-01

    Adenosine is a signaling molecule and downstream product of ATP that acts as a neuromodulator. Adenosine regulates physiological processes, such as neurotransmission and blood flow, on a time scale of minutes to hours. Recent developments in electrochemical techniques, including fast-scan cyclic voltammetry (FSCV), have allowed direct detection of adenosine with sub-second temporal resolution. FSCV studies have revealed a novel mode of rapid signaling that lasts only a few seconds. This rapid release of adenosine can be evoked by electrical or mechanical stimulations or it can be observed spontaneously without stimulation. Adenosine signaling on this time scale is activity dependent; however, the mode of release is not fully understood. Rapid adenosine release modulates oxygen levels and evoked dopamine release, indicating that adenosine may have a rapid modulatory role. In this review, we outline how FSCV can be used to detect adenosine release, compare FSCV with other techniques used to measure adenosine, and present an overview of adenosine signaling that has been characterized using FSCV. These studies point to a rapid mode of adenosine modulation, whose mechanism and function will continue to be characterized in the future.

  5. Intracerebral adenosine infusion improves neurological outcome after transient focal ischemia in rats.

    Science.gov (United States)

    Kitagawa, Hisashi; Mori, Atsushi; Shimada, Jun; Mitsumoto, Yasuhide; Kikuchi, Tetsuro

    2002-04-01

    Second Institute of New Drug Research, Otsuka Pharmaceutical Co., Ltd., Tokushima, Japan In order to elucidate the role of adenosine in brain ischemia, the possible protective effects of adenosine on ischemic brain injury were investigated in a rat model of brain ischemia both in vitro and in vivo. Exogenous adenosine dose-dependently rescued cortical neuronal cells from injury after glucose deprivation in vitro. Adenosine (1 mM) also significantly reduced hypoglycemia/hypoxia-induced glutamate release from the hippocampal slice. In a rat model of transient middle cerebral artery occlusion (MCAO), extracellular adenosine concentration was increased immediately after occlusion, and then returned to the baseline by 30 min after reperfusion. Adenosine infusion through a microdialysis probe into the ipsilateral striatum (1 mM adenosine, 2 microl min(-1), total 4.5 h from the occlusion to 3 h after reperfusion) showed a significant improvement in the neurological outcome, and about 25% reduction of infarct volume, although the effect did not reach statistical significance, compared with the vehicle-treated group at 20 h after 90 min of MCAO. These results demonstrated the neuroprotective effect of adenosine against ischemic brain injury both in vitro and in vivo, suggesting the possible therapeutic application of adenosine regulating agents, which inhibit adenosine uptake or metabolism to enhance or maintain extracellular endogenous adenosine levels, for stroke treatment.

  6. Adenosine transiently modulates stimulated dopamine release in the caudate-putamen via A1 receptors.

    Science.gov (United States)

    Ross, Ashley E; Venton, B Jill

    2015-01-01

    Adenosine modulates dopamine in the brain via A1 and A2A receptors, but that modulation has only been characterized on a slow time scale. Recent studies have characterized a rapid signaling mode of adenosine that suggests a possible rapid modulatory role. Here, fast-scan cyclic voltammetry was used to characterize the extent to which transient adenosine changes modulate stimulated dopamine release (5 pulses at 60 Hz) in rat caudate-putamen brain slices. Exogenous adenosine was applied and dopamine concentration monitored. Adenosine only modulated dopamine when it was applied 2 or 5 s before stimulation. Longer time intervals and bath application of 5 μM adenosine did not decrease dopamine release. Mechanical stimulation of endogenous adenosine 2 s before dopamine stimulation also decreased stimulated dopamine release by 41 ± 7%, similar to the 54 ± 6% decrease in dopamine after exogenous adenosine application. Dopamine inhibition by transient adenosine was recovered within 10 min. The A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine blocked the dopamine modulation, whereas dopamine modulation was unaffected by the A2A receptor antagonist SCH 442416. Thus, transient adenosine changes can transiently modulate phasic dopamine release via A1 receptors. These data demonstrate that adenosine has a rapid, but transient, modulatory role in the brain. Here, transient adenosine was shown to modulate phasic dopamine release on the order of seconds by acting at the A1 receptor. However, sustained increases in adenosine did not regulate phasic dopamine release. This study demonstrates for the first time a transient, neuromodulatory function of rapid adenosine to regulate rapid neurotransmitter release.

  7. CD73-derived adenosine and tenascin-C control cytokine production by epicardium-derived cells formed after myocardial infarction.

    Science.gov (United States)

    Hesse, Julia; Leberling, Stella; Boden, Elisabeth; Friebe, Daniela; Schmidt, Timo; Ding, Zhaoping; Dieterich, Peter; Deussen, Andreas; Roderigo, Claudia; Rose, Christine R; Floss, Doreen M; Scheller, Jürgen; Schrader, Jürgen

    2017-03-31

    Epicardium-derived cells (EPDCs) play a fundamental role in embryonic cardiac development and are reactivated in the adult heart in response to myocardial infarction (MI). In this study, EPDCs from post-MI rat hearts highly expressed the ectoenzyme CD73 and secreted the profibrotic matricellular protein tenascin-C (TNC). CD73 on EPDCs extensively generated adenosine from both extracellular ATP and NAD. This in turn stimulated the release of additional nucleotides from a Brefeldin A-sensitive intracellular pool via adenosine-A2BR signaling, forming a positive-feedback loop. A2BR activation in addition strongly promoted the release of major regulatory cytokines, such as IL-6, IL-11, and VEGF. TNC was found to stimulate EPDC migration and, together with ATP-P2X7R signaling, to activate inflammasomes in EPDCs via TLR4. Our results demonstrate that EPDCs are an important source of various proinflammatory factors in the post-MI heart controlled by purinergic and TNC signaling.-Hesse, J., Leberling, S., Boden, E., Friebe, D., Schmidt, T., Ding, Z., Dieterich, P., Deussen, A., Roderigo, C., Rose, C. R., Floss, D. M., Scheller, J., Schrader, J. CD73-derived adenosine and tenascin-C control cytokine production by epicardium-derived cells formed after myocardial infarction.

  8. Dual sources of water overprinting on the low zircon δ18O metamorphic country rocks: Disequilibrium constrained through inverse modelling of partial reequilibration

    Science.gov (United States)

    Wei, Chun-Sheng; Zhao, Zi-Fu

    2017-01-01

    Since water is only composed of oxygen and hydrogen, δ18O and δ2H values are thus utilized to trace the origin of water(s) and quantify the water-rock interactions. While Triassic high pressure (HP) and ultrahigh pressure (UHP) metamorphic rocks across the Dabie-Sulu orogen in central-eastern China have been well documented, postcollisional magmatism driven hydrothermal systems are little known. Here we show that two sources of externally derived water interactions were revealed by oxygen isotopes for the gneissic country rocks intruded by the early Cretaceous postcollisional granitoids. Inverse modellings indicate that the degree of disequilibrium (doD) of meteoric water interactions was more evident than that of magmatic one (−65 ± 1o vs. −20 ± 2°); the partial reequilibration between quartz and alkali feldspar oxygen isotopes with magmatic water was achieved at 340 °C with a water/rock (W/R) ratio of about 1.2 for an open-hydrothermal system; two-stage meteoric water interactions were unraveled with reequilibration temperatures less than 300 °C and W/R ratios around 0.4. The lifetime of fossil magmatic hydrothermal system overprinted on the low zircon δ18O orthogneissic country rocks was estimated to maintain up to 50 thousand years (Kyr) through oxygen exchange modellings. Four-stage isotopic evolutions were proposed for the magmatic water interacted gneiss. PMID:28091552

  9. Dual sources of water overprinting on the low zircon δ18O metamorphic country rocks: Disequilibrium constrained through inverse modelling of partial reequilibration

    Science.gov (United States)

    Wei, Chun-Sheng; Zhao, Zi-Fu

    2017-01-01

    Since water is only composed of oxygen and hydrogen, δ18O and δ2H values are thus utilized to trace the origin of water(s) and quantify the water-rock interactions. While Triassic high pressure (HP) and ultrahigh pressure (UHP) metamorphic rocks across the Dabie-Sulu orogen in central-eastern China have been well documented, postcollisional magmatism driven hydrothermal systems are little known. Here we show that two sources of externally derived water interactions were revealed by oxygen isotopes for the gneissic country rocks intruded by the early Cretaceous postcollisional granitoids. Inverse modellings indicate that the degree of disequilibrium (doD) of meteoric water interactions was more evident than that of magmatic one (-65 ± 1o vs. -20 ± 2°) the partial reequilibration between quartz and alkali feldspar oxygen isotopes with magmatic water was achieved at 340 °C with a water/rock (W/R) ratio of about 1.2 for an open-hydrothermal system; two-stage meteoric water interactions were unraveled with reequilibration temperatures less than 300 °C and W/R ratios around 0.4. The lifetime of fossil magmatic hydrothermal system overprinted on the low zircon δ18O orthogneissic country rocks was estimated to maintain up to 50 thousand years (Kyr) through oxygen exchange modellings. Four-stage isotopic evolutions were proposed for the magmatic water interacted gneiss.

  10. Deficits in Endogenous Adenosine Formation by Ecto-5′-Nucleotidase/CD73 Impair Neuromuscular Transmission and Immune Competence in Experimental Autoimmune Myasthenia Gravis

    Directory of Open Access Journals (Sweden)

    Laura Oliveira

    2015-01-01

    Full Text Available AMP dephosphorylation via ecto-5′-nucleotidase/CD73 is the rate limiting step to generate extracellular adenosine (ADO from released adenine nucleotides. ADO, via A2A receptors (A2ARs, is a potent modulator of neuromuscular and immunological responses. The pivotal role of ecto-5′-nucleotidase/CD73, in controlling extracellular ADO formation, prompted us to investigate its role in a rat model of experimental autoimmune myasthenia gravis (EAMG. Results show that CD4+CD25+FoxP3+ regulatory T cells express lower amounts of ecto-5′-nucleotidase/CD73 as compared to controls. Reduction of endogenous ADO formation might explain why proliferation of CD4+ T cells failed upon blocking A2A receptors activation with ZM241385 or adenosine deaminase in EAMG animals. Deficits in ADO also contribute to neuromuscular transmission failure in EAMG rats. Rehabilitation of A2AR-mediated immune suppression and facilitation of transmitter release were observed by incubating the cells with the nucleoside precursor, AMP. These findings, together with the characteristic increase in serum adenosine deaminase activity of MG patients, strengthen our hypothesis that the adenosinergic pathway may be dysfunctional in EAMG. Given that endogenous ADO formation is balanced by ecto-5′-nucleotidase/CD73 activity and that A2ARs exert a dual role to restore use-dependent neurocompetence and immune suppression in myasthenics, we hypothesize that stimulation of the two mechanisms may have therapeutic potential in MG.

  11. Dual-source Dual-energy Computed Tomography Imaging of Acute Necrotizing Pancreatitis——Priliminary Study%双源CT双能量扫描对急性坏死性胰腺炎影像诊断价值的初步探讨

    Institute of Scientific and Technical Information of China (English)

    袁元; 黄子星; 李真林; 宋彬; 邓莉萍

    2011-01-01

    目的 初步探讨双源CT双能量技术扫描对急性坏死性胰腺炎影像诊断的价值.方法 回顾性分析32例确诊急性坏死性胰腺炎患者的双源CT双能量门静脉期增强图像,测量、计算并评估80 kV、140 kV和加权融合120kV图像中的胰腺实质-坏死灶CT差值、胰腺实质-坏死灶对比噪声比以及图像主观诊断评分.结果 80 kV、140 kV和加权融合120 kV图像中胰腺实质-坏死灶CT差值分别为(67.22±21.11)HU、(42.91±15.12)HU、(48.78±16.13)HU;胰腺实质-坏死灶对比噪声比分别为8.35±3.63、5.89±2.67、7.72±3.58;图像主观诊断评分分别为3.87±0.34、3.28±0.81、3.56±0.67.3组图像中的胰腺实质-坏死灶CT差值、胰腺实质-坏死灶对比噪声比以及图像主观诊断评分之间差异均有统计学意义(P<0.05).其中80 kV图像的胰腺实质-坏死灶CT差值、胰腺实质-坏死灶对比噪声比和图像主观诊断评分均高于140 kV和加权融合120 kV图像.结论 急性坏死性胰腺炎患者双源CT双能量门静脉期增强扫描,80 kV图像对坏死灶的显示优于140 kV和加权融合120 kV图像.%Objective To investigate the clinical value of dual-source computed tomography dual-energy technology in the imaging diagnosis of acute necrotizing pancreatitis. Methods Thirty-two cases with diagnosed acute necrotizing pancreatitis and underwent contrast-enhanced dual-source dual-energy CT in portal venous phase were retrospectively analyzed. Difference of CT value between pancreatic parenchyma and necrosis, contrast to noise ratio of pancreatic parenchyma-to-necrosis and score of subjective diagnosis were measured, calculated and assessed on CT images of 80 kV, 140 kV and weighted-average 120 kV. Results The difference of CT value between pancreatic parenchyma and necrosis in the images of 80 kV, 140 kV and weighted-average 120 kV was (67. 22± 21. 11) HU, (42. 91 ±15. 12) HU, (48. 78 ±16. 13) HU; contrast to noise ratio of

  12. Dual 10Be isotope systems constrain the source of sediment and rate of erosion for the tropical Barron River catchment, Queensland, Australia

    Science.gov (United States)

    Nichols, K. K.; Bierman, P. R.; Reusser, L. J.; Portenga, E.; Matmon, A.; Rood, D. H.

    2010-12-01

    In order to understand source of sediment and rate of erosion for Barron River catchment, which heads on the Atherton Tablelands of northeast Australia, crosses the northern Queensland escarpment and drains into the Coral Sea, we collected fluvial sediment and measured both in situ and meteoric 10Be contents on the medium sand fraction. We collected fourteen samples from rivers and streams including large regional drainages and small tributaries. The upland basins are characterized by lower relief and less precipitation than the steeper and wetter escarpment basins. One sample is quartz sand from the Coral Sea beach at Yorkey's Knob, below the escarpment. Sand from the Barron River upstream of the escarpment integrates the upland basins and has an in situ 10Be concentration of 2.31±0.84 x105atoms/g and an erosion rate of 17.2 m/My (calculated using the CRONOS on-line calculator). This is similar to a major upland tributary (2.51±0.40 x105 atoms/g; 15.2 m/My) and two smaller upstream tributaries (20.5 m/My and 21.4 m/My). Escarpment streams have less in situ 10Be in their sediment (mean = 1.64±0.55 x 105 atoms/g, n=8) and higher basin area-weighted erosion rates (37.2 m/My). Based on the in situ measurements, the uplands are eroding at approximately half the rate of the escarpment basins. The beach sand has an in situ 10Be concentration (2.75±0.19 x 105 atoms/g) similar to the upland sediment suggesting that the source of beach sand is the larger but more slowly eroding Tablelands. In contrast, the meteoric 10Be concentrations of Barron River sand-sized sediment collected above the escarpment is ~4 fold lower (2.55x107 atoms/g) than the average meteoric 10Be concentration of the 8 escarpment samples (9.94±4.49 x107 atoms/g). This discrepancy cannot be explained by differences in annual average precipitation which ranges only from 1.9 to 2.3 m/yr but likely results from the deep mobility of meteoric 10Be in oxic Tableland soils. Considering meteoric 10Be as a

  13. Adenosine gates synaptic plasticity at hippocampal mossy fiber synapses

    Science.gov (United States)

    Moore, Kimberly A.; Nicoll, Roger A.; Schmitz, Dietmar

    2003-11-01

    The release properties of synapses in the central nervous system vary greatly, not only across anatomically distinct types of synapses but also among the same class of synapse. This variation manifests itself in large part by differences in the probability of transmitter release, which affects such activity-dependent presynaptic forms of plasticity as paired-pulse facilitation and frequency facilitation. This heterogeneity in presynaptic function reflects differences in the intrinsic properties of the synaptic terminal and the activation of presynaptic neurotransmitter receptors. Here we show that the unique presynaptic properties of the hippocampal mossy fiber synapse are largely imparted onto the synapse by the continuous local action of extracellular adenosine at presynaptic A1 adenosine receptors, which maintains a low basal probability of transmitter release.

  14. Expression of human adenosine deaminase in murine hematopoietic cells.

    Science.gov (United States)

    Belmont, J W; MacGregor, G R; Wager-Smith, K; Fletcher, F A; Moore, K A; Hawkins, D; Villalon, D; Chang, S M; Caskey, C T

    1988-01-01

    Multiple replication-defective retrovirus vectors were tested for their ability to transfer and express human adenosine deaminase in vitro and in vivo in a mouse bone marrow transplantation model. High-titer virus production was obtained from vectors by using both a retrovirus long terminal repeat promoter and internal transcriptional units with human c-fos and herpes virus thymidine kinase promoters. After infection of primary murine bone marrow with one of these vectors, human adenosine deaminase was detected in 60 to 85% of spleen colony-forming units and in the blood of 14 of 14 syngeneic marrow transplant recipients. This system offers the opportunity to assess methods for increasing efficiency of gene transfer, for regulation of expression of foreign genes in hematopoietic progenitors, and for long-term measurement of the stability of expression in these cells. Images PMID:3072474

  15. Evidence for an A1-adenosine receptor in the guinea-pig atrium.

    Science.gov (United States)

    Collis, M. G.

    1983-01-01

    1 The purpose of this study was to determine whether the adenosine receptor that mediates a decrease in the force of contraction of the guinea-pig atrium is of the A1- or A2-sub-type. 2 Concentration-response curves to adenosine and a number of 5'- and N6-substituted analogues were constructed and the order of potency of the purines was: 5'-N-cyclopropylcarboxamide adenosine (NCPCA) = 5'-N-ethylcarboxamide adenosine (NECA) greater than N6cyclohexyladenosine (CHA) greater than L-N6-phenylisopropyl adenosine (L-PIA) = 2-chloroadenosine- greater than adenosine greater than D-N6-phenylisopropyl adenosine (D-PIA). 3 The difference in potency between the stereoisomers D- and L-PIA was over 100 fold. 4 The adenosine transport inhibitor, dipyridamole, potentiated submaximal responses to adenosine but had no significant effect on those evoked by the other purines. 5 Theophylline antagonized responses evoked by all purines, and with D-PIA revealed a positive inotropic effect that was abolished by atenolol. 6 The results indicate the existence of an adenosine A1-receptor in the guinea-pig atrium. PMID:6297647

  16. Adenosine-mediated modulation of ventral horn interneurons and spinal motoneurons in neonatal mice.

    Science.gov (United States)

    Witts, Emily C; Nascimento, Filipe; Miles, Gareth B

    2015-10-01

    Neuromodulation allows neural networks to adapt to varying environmental and biomechanical demands. Purinergic signaling is known to be an important modulatory system in many parts of the CNS, including motor control circuitry. We have recently shown that adenosine modulates the output of mammalian spinal locomotor control circuitry (Witts EC, Panetta KM, Miles GB. J Neurophysiol 107: 1925-1934, 2012). Here we investigated the cellular mechanisms underlying this adenosine-mediated modulation. Whole cell patch-clamp recordings were performed on ventral horn interneurons and motoneurons within in vitro mouse spinal cord slice preparations. We found that adenosine hyperpolarized interneurons and reduced the frequency and amplitude of synaptic inputs to interneurons. Both effects were blocked by the A1-type adenosine receptor antagonist DPCPX. Analysis of miniature postsynaptic currents recorded from interneurons revealed that adenosine reduced their frequency but not amplitude, suggesting that adenosine acts on presynaptic receptors to modulate synaptic transmission. In contrast to interneurons, recordings from motoneurons revealed an adenosine-mediated depolarization. The frequency and amplitude of synaptic inputs to motoneurons were again reduced by adenosine, but we saw no effect on miniature postsynaptic currents. Again these effects on motoneurons were blocked by DPCPX. Taken together, these results demonstrate differential effects of adenosine, acting via A1 receptors, in the mouse spinal cord. Adenosine has a general inhibitory action on ventral horn interneurons while potentially maintaining motoneuron excitability. This may allow for adaptation of the locomotor pattern generated by interneuronal networks while helping to ensure the maintenance of overall motor output.

  17. The Monte Carlo Simulation of Tsinghua Homo-Source Dual-Beam Medical Accelerator%清华同源双束医用加速器蒙特卡罗模拟

    Institute of Scientific and Technical Information of China (English)

    马悦; 吴朝霞; 王石; 刘亚强

    2011-01-01

    Objective: To apply Monte Carlo method in simulating the Homo-Source Dual-Beam medical accelerator developed by Tsinghua University and lay the foundation for future researches on the Accelerator' s KV energy dose distribution in an image-guided radiotherapy procedure. Methods: (1)Using Monte Carlo's BEAMnrc program for simulating the head of Tsinghua Homo-Source Dual-Beam Medical Accelerator we obtained the Phase Space file which would be used as the source for the next step. (2) Using Monte Carlo' s DOSXYZnre program we calculated the percent depth dose (PDD) and off axis ratio (OAR), dealt the dose data by MATLAB program and displayed them in EXCEL. (3) Analyzed the impact of the Monte Carlo simulated parameters on the final outcome was analyzed. (4)Compared the PDD and OAR calculated with the measured of identical condition. Results: The PDD and OAR in water phantom simulated using Monte Carlo method were well matched with those measured in the actual experiments and the Accelerator' s Monte Carlo model was achieved. Conclusions: The Accelerator's Monte Carlo simulated parameters of KV energy are apparently different from that of High-energy. To obtain the accurate Accelerator's Monte Carlo model, it is important to choose proper electron beam energy and electron space density distribution. The Accelerator's Monte Carlo model can be used in future researches on the image dose distribution.%目的:使用蒙特卡罗方法模拟清华大学自主研制的同源双束医用加速器,为今后研究该设备KV级能量在放射治疗中成像剂量分布奠定基础.方法:(1)借助蒙卡BEAMnrc程序模拟加速器机头得到相空间文件.(2)以该相空间文件为源,使用蒙卡DOSXYZnrc程序计算水模体中百分深度剂量(percent depth dose,PDD)和离轴比(off axis ratio,OAR),采用MATLAB编程提取剂量数据显示于EXCEL.(3)分析蒙卡模拟参数对结果的影响.(4)对比实测调整模拟参数.结果:蒙卡模拟所得水模体中PDD

  18. Pharmacology of the Adenosine A3 Receptor in the Vasculature and Essential Hypertension

    Science.gov (United States)

    Ho, Ming-Fen; Low, Leanne M.; Rose’Meyer, Roselyn B.

    2016-01-01

    Background Essential hypertension is considered to be a multifactorial disorder and its aetiology has yet to be clearly identified. As the adenosine receptors have a significant role in mediating vasodilation, alterations in their structures or signalling pathways may be involved in the development of hypertension. This study aimed to measure the expression of adenosine A3 receptors in a range of cardiovascular tissues and determine whether they could be altered with essential hypertension, and to functionally test responses to adenosine A3 receptor agonists in coronary blood vessels using the isolated perfused heart preparation. Methods mRNA samples from cardiovascular tissues and a range of blood vessels were collected from 10 week old male spontaneously hypertensive rats and age-gender matched Wistar rats (n = 8). The Langendorff heart perfusion preparation was used to characterise adenosine A3 receptor mediated coronary vasodilation in the rat heart. Results Adenosine A3 receptor agonists induced coronary vasodilation. The expression of adenosine A3 receptors in cardiovascular tissues was altered in a tissue-specific pattern. Specifically, down-regulation of adenosine A3 receptor expression occurred in hypertensive hearts, which might be associated with attenuated vasodilator responses observed in coronary vessels to adenosine A3 receptor agonists. Conclusions This study demonstrated alterations in the expression of adenosine A3 receptors occurred in a tissue specific mode, and reduced adenosine A3 receptor mediated coronary vasodilation in hearts from spontaneously hypertensive rats. Our findings with regard to changes in the adenosine A3 receptor in hypertensive hearts suggest that adenosine A3 receptor might play a role in the physiopathology of essential hypertension and potentially open the way to pharmacologic manipulation of vasomotor activity by the use of adenosine A3 receptor agonists. PMID:26907173

  19. Adenosine receptors and stress : Studies using methylmercury, caffeine and hypoxia

    OpenAIRE

    Björklund, Olga

    2008-01-01

    Brain development is a precisely organized process that can be disturbed by various stress factors present in the diet (e.g. exposure to xenobiotics) as well as insults such as decreased oxygen supply. The consequent adverse changes in nervous system function may not necessarily be apparent until a critical age when neurodevelopmental defects may be unmasked by a subsequent challenge. Adenosine and its receptors (AR) (A1, A2A, A2B and A3) which participate in the brain stres...

  20. Severe combined immunodeficiency due to adenosine deaminase deficiency.

    Science.gov (United States)

    Hussain, Waqar; Batool, Asma; Ahmed, Tahir Aziz; Bashir, Muhammad Mukarram

    2012-03-01

    Severe Combined Immunodeficiency is the term applied to a group of rare genetic disorders characterised by defective or absent T and B cell functions. Patients usually present in first 6 months of life with respiratory/gastrointestinal tract infections and failure to thrive. Among the various types of severe combined immunodeficiency, enzyme deficiencies are relatively less common. We report the case of a 6 years old girl having severe combined immunodeficiency due to adenosine deaminase deficiency.

  1. Adenosine receptors in post-mortem human brain.

    Science.gov (United States)

    James, S; Xuereb, J H; Askalan, R; Richardson, P J

    1992-01-01

    1. Adenosine A2-like binding sites were characterized in post-mortem human brain membranes by examining several compounds for their ability to displace [3H]-CGS 21680 (2[p-(2 carboxyethyl)-phenethylamino]-5'-N-ethylcarboxamido adenosine) binding. 2. Two A2-like binding sites were identified in the striatum. 3. The more abundant striatal site was similar to the A2a receptor previously described in rat striatum, both in its pharmacological profile and striatal localization. 4. The less abundant striatal site had a pharmacological profile similar to that of the binding site characterized in the other brain regions examined. This was intermediate in character between A1 and A2 and may represent another adenosine receptor subtype. 5. The co-purification of [3H]-CGS 21680 binding during immunoisolation of human striatal cholinergic membranes was used to assess the possible cholinergic localization of A2-like binding sites in the human striatum. Only the more abundant striatal site co-purified with cholinergic membranes. This suggests that this A2a-like site is present on cholinergic neurones in the human striatum.

  2. Cordyceps pruinosa produces cordycepin and N6-(2-hydroxyethyl-adenosine in culture

    Directory of Open Access Journals (Sweden)

    Meng Zebin

    2014-01-01

    Full Text Available Cordyceps species are entomophagous pathogens with medicinal properties, mostly linked to cordycepin and N6- (2-hydroxyethyl-adenosine (HEA. An isolate of Cordyceps pruinosa (GZUCC 8552 was obtained from a fruiting body formed on the cocoon a Limacodidae insect collected in Guizhou Province, China. Morphological and molecular analysis (combined 5.8S ITS, RPB1 and 18S RNA confirmed the species to be Cordyceps pruinosa. Metabolites of the isolate grown in liquid static and solid-state media were established by HPLC-MS. Cordycepin (5.311 mg/g and HEA (0.558 mg/g were produced by this strain. This is the first record of cordycepin from an isolate of Cordyceps pruinosa. As Cordyceps pruinosa is a good source of cordycepin and HEA, it could be used as an alternative to the over-collected Cordyceps sinensis.

  3. Simulation of dual transponder carrier ranging measurements

    Institute of Scientific and Technical Information of China (English)

    Xiang-yu ZHAO; Xiao-jun JIN; Zhong-he JIN

    2009-01-01

    The most dominant error source for microwave ranging is the frequency instability of the oscillator that generates the carrier phase signal. The oscillator noise is very difficult to filter due to its extremely low frequency. A dual transponder carrier ranging method can effectively minimize the oscillator noise by combing the reference phase and the to-and-fro measurement phase from the same single oscillator. This method does not require an accurate time tagging system, since it extracts phases on the same satellite. This paper analyzes the dual transponder carrier ranging system by simulation of the phase measurements with comprehensive error models. Both frequency domain and time domain noise transfer characteristics were simulated to compare them with dual one-way ranging. The simulation results in the two domains conformed to each other and demonstrated that a high level of accuracy can also be achieved by use of the dual transponder carrier ranging system, with relatively simple instruments.

  4. Feasibility study of dual-source CT high-pitch aorta angiography%双源CT大螺距模式主动脉成像的可行性研究

    Institute of Scientific and Technical Information of China (English)

    王利军; 孙凯; 王志琴; 董馨; 贾海亮; 杜晓辉; 张皓成

    2014-01-01

    Objective: To investigate the feasibility, image quality and radiation dose for high-pitch dual-source CT angiography (CTA) of the whole aorta. Methods: Each group of 62 and 58 patients underwent CTA either on dual-source CT device with high-pitch mode with a pitch of 3.2(group A) or conventional single-source (group B). Evaluate the image quality and radiation dose. Image quality of the aorta was independently assessed by two readers. Scanner-reported dose-length product values were used to estimate effective dose values. Results:Subjective scoring of image quality were significantly increased in the high-pitch examination protocol (2.66±0.51 vs.2.14±0.47, P<0.01) for groups A and B. Objective scoring of image quality were not significantly different. The imaging length was not significantly different, but the imaging time was significantly shorter in the high-pitch group (1.61±0.23 vs.6.52±1.41s P<0.01) for groups A and B. Radiation dose was lower. (3.97±1.07 mSv vs. 15.18±2.58 mSv, P<0.01). Conclusion:High-pitch dual-source CT angiography of the whole aorta is feasible in unselected patients. As a significant advantage over regular pitch protocols, shorter scan time, lower radiation dose and less motion artifacts is possible. this CT mode bears potential to become a standard CT protocol.%目的:利用双源CT的大螺距模式对主动脉全程扫描成像,对照评价其图像质量和有效辐射剂量,旨在研究双源CT大螺距模式行主动脉全程扫描的可行性。方法:将接受主动脉CT血管造影(CTA)的患者随机分为A、B两组,A组62例,B组58例。A组使用大螺距扫描模式,B组使用常规扫描模式;图像质量评价分客观和主观两种方法,客观评价包括图像噪声及信噪比,主观评价由2名放射科医生独立完成。辐射剂量统计使用设备自带的数据记录。结果:大螺距模式主观图像质量评分(2.66±0.51)较常规扫描组(2.14±0.47)高

  5. Contraction induced secretion of VEGF from skeletal muscle cells is mediated by adenosine

    DEFF Research Database (Denmark)

    Høier, Birgitte; Olsen, Karina; Nyberg, Michael Permin

    2010-01-01

    The role of adenosine and contraction for secretion of VEGF in skeletal muscle was investigated in human subjects and rat primary skeletal muscle cells. Microdialysis probes were inserted into the thigh muscle of seven male subjects and dialysate was collected at rest, during infusion of adenosine...... and contraction caused secretion of VEGF (pcontraction induced secretion of VEGF protein was abolished by the A(2B) antagonist enprofyllin and markedly reduced by inhibition of PKA or MAPK. The results demonstrate that adenosine causes secretion of VEGF from human skeletal muscle cells...... and that the contraction induced secretion of VEGF is partially mediated via adenosine acting on A(2B) adenosine receptors. Moreover, the contraction induced secretion of VEGF protein from muscle is dependent on both PKA and MAPK activation, but only the MAPK pathway appears to be adenosine dependent....

  6. [Effects of dopamine and adenosine on regulation of water-electrolyte exchange in Amoeba proteus].

    Science.gov (United States)

    Bagrov, Ia Iu; Manusova, N B

    2014-01-01

    Dopamine and adenosine both regulate transport of sodium chloride in the renal tubules in mammals. We have studied the effect of dopamine and adenosine on spontaneous activity of contractile vacuole of Amoeba proteous. Both substances stimulated contractile vacuole. The effect of dopamine was suppressed by D2 receptor antagonist, haloperidol, but not by D1 antagonist, SCH 39166. Adenylate cyclase inhibitor, 2.5-dideoxyadenosine, suppressed the effect of dopamine, but not of adenosine. Inhibitor of protein kinase C, staurosporine, in contrast, blocked the effect of adenosine, but not dopamine. Notably, dopamine opposed effect of adenosine and vice versa. These results suggest that similar effects of dopamine and adenosine could be mediated by different intracellulare mechanisms.

  7. Acute hyperammonemia and systemic inflammation is associated with increased extracellular brain adenosine in rats

    DEFF Research Database (Denmark)

    Bjerring, Peter Nissen; Dale, Nicholas; Larsen, Fin Stolze

    2015-01-01

    Acute liver failure (ALF) can lead to brain edema, cerebral hyperperfusion and intracranial hypertension. These complications are thought to be mediated by hyperammonemia and inflammation leading to altered brain metabolism. As increased levels of adenosine degradation products have been found...... in brain tissue of patients with ALF we investigated whether hyperammonemia could induce adenosine release in brain tissue. Since adenosine is a potent vasodilator and modulator of cerebral metabolism we furthermore studied the effect of adenosine receptor ligands on intracranial pressure (ICP......) and cerebral blood flow (CBF). We measured the adenosine concentration with biosensors in rat brain slices exposed to ammonia and in a rat model with hyperammonemia and systemic inflammation. Exposure to ammonia in concentrations from 0.15-10 mM led to increases in the cortical adenosine concentration up to 18...

  8. Feasibility and Diagnostic Accuracy for Assessment of Coronary Artery Stenosis of Prospectively Electrocardiogram-gated High-pitch Spiral Acquisition Mode Dual-source CT Coronary Angiography in Patients with Relatively Higher Heart Rates:in Comparison wit

    Institute of Scientific and Technical Information of China (English)

    Kai Sun; Rui-juan Han; Li-fang Cui; Rui-ping Zhao; Li-jun Ma; Li-jun Wang; Li-gang Li; Chang-yong Li

    2012-01-01

    Objective To prospectively investigate the diagnostic accuracy for coronary artery stenosis of prospectively electrocardiogram-triggered spiral acquisition mode (high pitch mode) dual-source computed tomography coronary angiography (CTCA) in patients with relatively higher heart rates (HR) compared with catheter coronary angiography (CCA).Methods Forty-seven consecutive patients with relatively higher HR (>65 and < 100 bpm) (20 male,27 female; age 55 ± 10 years) who both underwent dual-source CTCA and CCA were prospectively included in this study.All patients were performed CTCA using high pitch mode setting at 20%-30% of the R-R interval for the image acquisition.All coronary segments were evaluated by two blinded and independent observers with regard to image quality on a three-point scale (1:excellent to 3:non-diagnostic) and for the presence of significant coronary stenoses (defined as diameter narrowing exceeding 50%).Considered CCA as the standard of reference,the sensitivity,specificity,positive predictive value and negative predictive value were calculated.Radiation dose values were calculated using the dose-length product.Results Image quality was rated as being score 1 in 92.4% of segments,score 2 in 6.1% of segments and score 3 in 1.5% of segments.The average image quality score per segment was 1.064±0.306.The HR variability of patients with image score 1,2 and 3 were 2.29± 1.06 bpm,5.17± 1.37 bpm,8.88± 1.53 bpm,respectively.The average HR variability of patients with different image scores were significantly different (F=170.402,P=0.001).The sensitivity,specificity,positive and negative predictive values were 92.6%,97.0%,87.6%,98.3%,respe ctively,per segment and 90.0%,95.2%,85.3%,96.9%,respectively,per vessel and 100%,63.6%,90.0%,100%,respectively,per patient.The effective radiation dose was on average 0.86±0.16 mSv.Conclusion In patients with HR more than 65 bpm and below 100 bpm without cardiac arrhythmia

  9. 双源CT与冠状动脉造影评估冠状动脉支架内再狭窄%Dual-Source Computed Tomography and Coronary Angiography in Evaluation of In-Stent Restenosis

    Institute of Scientific and Technical Information of China (English)

    王联发; 纪勤炯; 朱有志; 侯勇; 黄猛珣; 顾磊

    2012-01-01

    目的 对比分析双源CT( dual-source CT,DSCT)与冠状动脉造影(coronary angiography,CAG)评估支架内再狭窄( in stent restenosis,ISR)的结果,探讨支架所在部位及支架大小对DSCT评估冠状动脉ISR的影响.方法 106例同期行DSCT及SCAG检查的支架术后的患者,以SCAG结果为标准,比较DSCT评估不同部位及大小支架ISR的敏感性、特异性及准确性.结果 173枚支架中有156枚支架DSCT显影良好.DSCT显示有ISR的支架33枚,CAG证实存在ISR的支架38枚,DSCT诊断ISR的敏感度和特异度分别为78.9%和97.5%,阳性预测值90.9%,阴性预测值93.5%,一致率为92.9%.DSCT对近心端支架再狭窄的检出率优于远心端支架;直径≥3.0 mm支架的ISR检出率优于直径<3.0mm支架.结论 支架内径大小及所在部位影响DSCT图像的显示.DSCT在评估ISR方面,可基本取代SCAG作为冠脉近端支架及大直径支架(支架直径≥3 mm)通畅情况的评估方式.%Objective To compare the results of dual-source CT(DSCT) and coronary angiography (CAG) in the diagnosis of in-stent restenosis ( ISR) , and discuss the influence of the positions and size of stents on the evaluation results of ISR by DSCT. Methods The 106 patients in the same period underwent DSCT and CAG were included in the study, analysis and comparison ISR of DSCT diagnostic sensitivity, specificity and accuracy to detect in-stent restenosis was evaluated referring to coronary angiography. ISR was defined as a lesion demonstrating stenosis greater than 50%. Results In all 173 stents, 156 stents could be assessed by DSCT. 33 stents could be detected ISR by DSCT.38 stents with ISR indicated by CAG. The sensitivity,specificity,positive and negative predictive value and accuracy to identify ISR was 78.9% ,97.5% ,90.9% and 93.5% ,92.9% .respectively. DSCT coronary artery proximal in-stent restenosis detection rate were superior to the distal stent. The detection with DSCT in-stent restenosis of positive

  10. Crystal Structure of Schistosoma mansoni Adenosine Phosphorylase/5’-Methylthioadenosine Phosphorylase and Its Importance on Adenosine Salvage Pathway

    Science.gov (United States)

    Torini, Juliana Roberta; Brandão-Neto, José; DeMarco, Ricardo; Pereira, Humberto D'Muniz

    2016-01-01

    Schistosoma mansoni do not have de novo purine pathways and rely on purine salvage for their purine supply. It has been demonstrated that, unlike humans, the S. mansoni is able to produce adenine directly from adenosine, although the enzyme responsible for this activity was unknown. In the present work we show that S. mansoni 5´-deoxy-5´-methylthioadenosine phosphorylase (MTAP, E.C. 2.4.2.28) is capable of use adenosine as a substrate to the production of adenine. Through kinetics assays, we show that the Schistosoma mansoni MTAP (SmMTAP), unlike the mammalian MTAP, uses adenosine substrate with the same efficiency as MTA phosphorolysis, which suggests that this enzyme is part of the purine pathway salvage in S. mansoni and could be a promising target for anti-schistosoma therapies. Here, we present 13 SmMTAP structures from the wild type (WT), including three single and one double mutant, and generate a solid structural framework for structure description. These crystal structures of SmMTAP reveal that the active site contains three substitutions within and near the active site when compared to it mammalian counterpart, thus opening up the possibility of developing specific inhibitors to the parasite MTAP. The structural and kinetic data for 5 substrates reveal the structural basis for this interaction, providing substract for inteligent design of new compounds for block this enzyme activity. PMID:27935959

  11. 基于实物期权的双源供应链柔性采购协调策略%A Coordination Contract Based on Real-option for Dual Sourcing Flexible Strategy

    Institute of Scientific and Technical Information of China (English)

    罗美玲; 李刚; 孙林岩; 苏鹏德

    2012-01-01

    The dual sourcing flexible strategy in a two-stage supply chain with a risk-averse supplier and a dominant retailer when integrating contracting and spot procurement under uncertainty demand is studied. The supply chain coordination mechanism based on real-option is proposed. In order to analyze the effects of risk aversion and the uncertainty of spot price on the retailer' s purchasing strategy and profits of supply chain members, an algorithm of solving the optimal option parameters is designed. The result shows that the real-option contract can achieve the supply chain coordination considering both the effects of spot procurement and risk aversion of the supplier.%在需求不确定下,由风险规避的供应商和占主导地位的零售商组成的二级供应链中,构建了在现货市场影响下基于实物期权的双源柔性采购协调模型,给出了实现供应链协调的最优期权参数的求解算法,探讨了现货市场价格不确定性和供应商风险规避特性对零售商采购策略和双方利润的影响.研究结果表明,在考虑现货市场影响和供应商风险规避的条件下,实物期权契约可以实现供应链协调.

  12. Accuracy, image quality and radiation dose comparison of high-pitch spiral and sequential acquisition on 128-slice dual-source CT angiography in children with congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Nie, Pei; Wang, Ximing; Cheng, Zhaoping; Ji, Xiaopeng; Duan, Yanhua [Shandong University, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong (China); Chen, Jiuhong [CT Research Collaboration, Siemens Ltd. China, Beijing (China)

    2012-10-15

    To compare accuracy, image quality and radiation dose between high-pitch spiral and sequential modes on 128-slice dual-source computed tomographic (DSCT) angiography in children with congenital heart disease (CHD). Forty patients suspected with CHD underwent 128-slice DSCT angiography with high-pitch mode and sequential mode respectively. All the anomalies were confirmed by the surgical and/or the conventional cardiac angiography (CCA) findings. The diagnostic accuracy, the subjective and objective image quality and effective radiation doses were compared. There was no significant difference in diagnostic accuracy ({chi}{sup 2} = 0.963, P > 0.05), the objective parameters for image quality (P > 0.05) and the image quality of great vessels (u = 167.500, P > 0.05) between the two groups. The image quality of intracardiac structures and coronary arteries was significantly better in the sequential mode group than that in the high-pitch group (u = 112.500 and 100.000, P < 0.05). The mean effective dose in high-pitch group (0.17 {+-} 0.05 mSv) was significantly lower (t = 5.287, P < 0.05) than that in the sequential mode group (0.29 {+-} 0.09 mSv). Both the high-pitch and the sequential modes for 128-slice DSCT angiography provide high accuracy for the assessment of CHD in children, while the high-pitch mode, even with some image quality decrease, further significantly lowers the radiation dose. (orig.)

  13. Low-dose prospectively electrocardiogram-gated axial dual-source CT angiography in patients with pulsatile bilateral bidirectional Glenn Shunt: an alternative noninvasive method for postoperative morphological estimation.

    Directory of Open Access Journals (Sweden)

    Xiaopeng Ji

    Full Text Available OBJECTIVE: To explore the clinical value of low-dose prospectively electrocardiogram-gated axial dual-source CT angiography (low-dose PGA scanning, CTA in patients with pulsatile bilateral bidirectional Glenn shunt (bBDG as an alternative noninvasive method for postoperative morphological estimation. METHODS: Twenty patients with pulsatile bBDG (mean age 4.2±1.6 years underwent both low-dose PGA scanning and conventional cardiac angiography (CCA for the morphological changes. The morphological evaluation included the anatomy of superior vena cava (SVC and pulmonary artery (PA, the anastomotic location, thrombosis, aorto-pulmonary collateral circulation, pulmonary arteriovenous malformations, etc. Objective and subjective image quality was assessed. Bland-Altman analysis and linear regression analyses were used to evaluate the correlation on measurements between CTA and CCA. Effective radiation dose of both modalities was calculated. RESULTS: The CT attenuation value of bilateral SVC and PA was higher than 300 HU. The average subjective image quality score was 4.05±0.69. The morphology of bilateral SVC and PA was displayed completely and intuitively by CTA images. There were 24 SVC above PA and 15 SVC beside PA. Thrombosis was found in 1 patient. Collateral vessels were detected in 13 patients. No pulmonary arteriovenous malformation was found in our study. A strong correlation (R2>0.8, P0.The mean effective dose of CTA and CCA was 0.50±0.17 mSv and 4.85±1.34 mSv respectively. CONCLUSION: CT angiography with a low-dose PGA scanning is an accurate and reliable noninvasive examination in the assessment of morphological changes in patients with pulsatile bBDG.

  14. The Impact of Dual-Source Support on Employees and the Mediating Role of Commitment%双来源支持感对员工的影响与承诺的中间作用

    Institute of Scientific and Technical Information of China (English)

    阎亮; 樊耘

    2016-01-01

    Through the empirical analysis based on the 432 supervisor-subordinate paired samples, the paper discusses the mechanisms that perceived dual-source support influences the employee turnover intention and organizational citizen⁃ship behavior through the organizational and supervisor commitment. The results show that perceived organizational sup⁃port positively significantly affects organizational commitment, and supervisory support positively significantly affects su⁃pervisor commitment;organizational commitment significantly negatively affects turnover intention, and positively affects organizational citizenship behavior; supervisor commitment positively influences organizational commitment, supervisor commitment′s effect on turnover intention and organizational citizen behavior are non-significant, while supervisor′s or⁃ganizational commitment has the moderating effect between subordinate′s supervisor commitment and organizational com⁃mitment.%通过432对样本的实证研究,本文分析了员工双来源支持感通过员工组织和主管承诺影响员工离职倾向和组织公民行为的作用机制。结果表明:员工组织支持感正向显著影响其组织承诺,主管支持感正向显著影响其主管承诺;员工的组织承诺负向显著影响离职倾向,正向显著影响组织公民行为;主管承诺正向显著影响其组织承诺,主管承诺对离职倾向和组织公民行为的影响不显著,主管的组织承诺在员工主管承诺和组织承诺关系间起到调节效应。

  15. Dual-Source Heat Pump System Combined with Photovoltaic Solar-Thermal (PV/T) Components%结合光伏光热组件的双源热泵系统的研究

    Institute of Scientific and Technical Information of China (English)

    于海照; 陈剑波; 姚晶珊

    2015-01-01

    As the electricity conversion efficiency of solar panel decreases with temperature rises, and the efficiency of the heat pump increases with the water temperature rises, a dual-source heat pump system is designed with combination of photovoltaic solar-thermal (PV/T) components. Whether the system can run reliably or not is verified through the outdoor experiments on the system, which also can verify whether the efficiency of the solar panels improves or not. The experimental results show that the system can run reliably, and conversion efficiency of PV/T components compared with the fixed angle of TPV components increase by about 0.3%. It can provide experimental data for the next step of the optimal operation.%考虑到太阳能电池板温度升高时其光电转换效率降低,以及水源温度升高时热泵运行效率增加的特点,设计出一套结合光伏光热(PV/T)组件的双源热泵系统。对该系统进行室外实际运行实验,通过实验验证系统是否能够稳定运行,并验证太阳能电池板降温提效的可行性。实验结果表明,该系统运行可靠,且组件电池转换效率与固定倾角的追踪式光伏(TPV)组件相比,提高0.3%左右,能够为下一步研究最优运行方式提供实验数据支持。

  16. Interaction between Intrathecal Gabapentin and Adenosine in the Formalin Test of Rats

    OpenAIRE

    Yoon, Myung Ha; Choi, Jeong Il; Park, Heon Chang; Bae, Hong Beom

    2004-01-01

    Spinal gabapentin and adenosine have been known to display an antinociceptive effect. We evaluated the nature of the interaction between gabapentin and adenosine in formalin-induced nociception at the spinal level. Male Sprague-Dawley rats were prepared for intrathecal catheterization. Pain was evoked by injection of formalin solution (5%, 50 µL) into the hindpaw. After examination of the effects of gabapentin and adenosine, the resulting interaction was investigated with isobolographic and f...

  17. Adenosine A2A Receptors Modulate Acute Injury and Neuroinflammation in Brain Ischemia.

    OpenAIRE

    Felicita Pedata; Anna Maria Pugliese; Elisabetta Coppi; Ilaria Dettori; Giovanna Maraula; Lucrezia Cellai; Alessia Melani

    2014-01-01

    The extracellular concentration of adenosine in the brain increases dramatically during ischemia. Adenosine A2A receptor is expressed in neurons and glial cells and in inflammatory cells (lymphocytes and granulocytes). Recently, adenosine A2A receptor emerged as a potential therapeutic attractive target in ischemia. Ischemia is a multifactorial pathology characterized by different events evolving in the time. After ischemia the early massive increase of extracellular glutamate is followed by ...

  18. Endogenous adenosine and hemorrhagic shock: effects of caffeine administration or caffeine withdrawal.

    OpenAIRE

    Conlay, L A; Evoniuk, G; Wurtman, R.J.

    1988-01-01

    Plasma adenosine concentrations doubled when rats were subjected to 90 min of profound hemorrhagic shock. Administration of caffeine (20 mg per kg of body weight), an adenosine-receptor antagonist, attenuated the hemorrhage-induced decrease in blood pressure. In contrast, chronic caffeine consumption (0.1% in drinking water), followed by a brief period of caffeine withdrawal, amplified the hypotensive response to hemorrhage. These data suggest that endogenous adenosine participates in the hyp...

  19. High-pitch dual-source CT pulmonary angiography in naturally breathing patients%自然呼吸下高螺距双源CT肺动脉造影方法探讨

    Institute of Scientific and Technical Information of China (English)

    邓国辉; 胡红杰; 张文明; 陈彬; 胡吉波

    2015-01-01

    目的探讨自然呼吸状态下高螺距双源CT肺血管造影(CTPA)技术对可疑肺栓塞患者应用的可行性、影像质量。方法对54例临床疑似肺动脉栓塞的患者(高螺距组),采用第二代双源CT行CT肺血管造影(CTPA),患者在自然呼吸下行高螺距CTPA检查(螺距为3.0,120kV,100mAs,50ml对比剂);另选前期检查患者54例作为常规组行常规CTPA检查(螺距为0.8,120kV,100mAs,80ml对比剂),深吸气后屏气扫描。记录PA强化程度、图像噪声、信噪比、图像的整体质量、扫描范围内肺动脉分支是否存在对比剂充盈不均和心脏、呼吸运动伪影以及辐射剂量,结果进行统计学分析。结果高螺距组肺动脉主干(PT)及尖段(S1)肺动脉、后基底段(S10)肺动脉的平均 CT值为(404±104)、(453±119)和(453±119)HU,平均图像背景噪声(11±2)HU,平均检查时间为(0.67±0.09)s,平均辐射剂量为(142±31)mGy cm,明显优于常规组(P<0.05)。检查图像无呼吸及心脏的运动伪影。肺动脉分支未见完全或部分缺损,所有患者均达到诊断要求。结论自然呼吸下状态高螺距双源CTPA检查能得到较高质量的图像,没有产生呼吸和心脏的运动伪影,且可避免出现瓦氏(Valsalva)呼吸所致的伪影。%Objective To assess the feasibility and image quality of high- pitch dual- source CT pulmonary angiography (CTPA) in natural y breathing patients with suspected pulmonary embolism. Methods One hundred and eight patients with clin-ically suspected pulmonary embolism underwent CTPA examination with dual- source CT scanner. Patients were randomly divid-ed into 2 groups:patients in high- pitch group (n=54) received high- pitch CTPA (pitch 3.0, 120 kV, 100 mAs, 50ml contrast ma-terial) without special breathing requirement, patients in routine group (n=54) received normal mode CTPA (pitch 0.8, 120 kV, 100 m

  20. Dual Income Taxes

    DEFF Research Database (Denmark)

    Sørensen, Peter Birch

    This paper discusses the principles and practices of dual income taxation in the Nordic countries. The first part of the paper explains the rationale and the historical background for the introduction of the dual income tax and describes the current Nordic tax practices. The second part...... of the paper focuses on the problems of taxing income from small businesses and the issue of corporate-personal tax integration under the dual income tax, considering alternative ways of dealing with these challenges. In the third and final part of the paper, I briefly discuss whether introducing a dual income...... tax could be relevant for New Zealand....

  1. Dual Income Taxes

    DEFF Research Database (Denmark)

    Sørensen, Peter Birch

    This paper discusses the principles and practices of dual income taxation in the Nordic countries. The first part of the paper explains the rationale and the historical background for the introduction of the dual income tax and describes the current Nordic tax practices. The second part...... of the paper focuses on the problems of taxing income from small businesses and the issue of corporate-personal tax integration under the dual income tax, considering alternative ways of dealing with these challenges. In the third and final part of the paper, I briefly discuss whether introducing a dual income...

  2. Topical adenosine increases the proportion of thick hair in Caucasian men with androgenetic alopecia.

    Science.gov (United States)

    Iwabuchi, Tokuro; Ideta, Ritsuro; Ehama, Ritsuko; Yamanishi, Haruyo; Iino, Masato; Nakazawa, Yosuke; Kobayashi, Takashi; Ohyama, Manabu; Kishimoto, Jiro

    2016-05-01

    Adenosine is an effective treatment for androgenetic alopecia (AGA) in Japanese men and women. Adenosine exerts its effects by significantly increasing the proportion of thick hair. In this study, we assessed the clinical outcome of adenosine treatment for 6 months in 38 Caucasian men. The change in proportion of thick hair (≥60 μm) compared with baseline in the adenosine group was significantly higher than that in the placebo group (P thick hair in Caucasian men with AGA as well as in Japanese men and women.

  3. Adenosine Modulates the Oocyte Developmental Competence by Exposing Stages and Synthetic Blocking during In Vitro Maturation.

    Science.gov (United States)

    Cheon, Yong-Pil

    2016-06-01

    Purine metabolism is known factor for nuclear maturation of oocytes through both follicle cells and oocyte itself. However, it is largely unknown the roles of purine metabolism in the oocyte competence for fertilization and early development. In this study, the effects of adenosine in oocyte competence for development were examined using adenosine and its synthetic inhibitors. Adenosine treatment from GV intact stage for 18 hr (fGV) caused of decrease the fertilization rate but of increase the cleavage rate compared from the other stage treatment groups. Hadacidin did not effect on fertilization rate but increased cleavage rate without stage specificity. Adenosine did not block the effects of hadacidin with the exception of fGV group. By the inhibition of purine synthetic pathways the fertilization rate was decreased in the fGV and fGVB groups but increased in the fMII group. Exogenous adenosine caused of decrease fertilization rate in the fGVB group but increase in the fMII group. Cleavage rate was dramatically increased in the adenosine treatment with synthetic inhibitors. It means that the metabolism of purine has stage specific effects on fertilization and cleavage. Exogenous adenosine had only can improve oocyte developmental competence when it treated at GV intact stage. On the other hand, endogenous synthesis in all maturation stage caused of increase the cleavage rate without effects on fertilization. These data suggest that adenosine at GV stage as a paracrine fashion and inhibitions of endogenous adenosine in all stage improve oocyte developmental competence..

  4. 基于无线通信网及GPS的双时钟源授时设计%Design of a Dual Clock Source Timing System Based on Radio Network and GPS

    Institute of Scientific and Technical Information of China (English)

    欧阳明星

    2013-01-01

    针对传统时钟走时不准,调校不方便的缺点,提出一种基于无线通信网及GPS的双时钟源授时系统设计,主机接收GPS卫星时间信号,通过无线通信网发送给所有子系统实现授时.为提高系统可靠性,设计DS12C887为主机备用时钟源,以备应急时使用,主机通过Internet网关接入互联网,实现远程控制及网络授时.系统硬件电路以STM8及STM32处理器为核心,使用CC1101射频通信模块构建无线通信网,设计无线通信协议及其组网策略,文章最后给出软件设计流程图.样机用于校园授时,控制打铃仪和万年历授时,运行稳定可靠.%Aimed at of traditional timer adjustment inconvenient and timing misfit,this paper explains a system design based on radio network and GPS dual timing source,the host receives satellites timing signal then it is sent to all subsystem through radio network.In order to improve its reliability,design DS12C887 as the reserve timing source to prepare for emergency use for host,host connected to the internet is to realize remote control or timing through network by internet gateway.System hardware circuit takes STM8 and STM32 as core processor and uses CC1101 RF communication module to build a radio network,designed radio protocols and its networking strategy,finally this paper explains software designed flow.Prototype run stable and reliable for campus grant for bell control and calendar timing.

  5. 双源 CT 软件对肺栓塞诊断的应用%Study of the diagnosis and clinical application of pulmonary embolism with dual source CT software

    Institute of Scientific and Technical Information of China (English)

    朱建国; 郭亮

    2014-01-01

    Objective:To investigate the value of dual source CT software in the diagnosis and clinical application of pulmonary artery embolism (PE).Methods:Sixty-six consecutive patients having suspected PE underwent CT pulmonary angiography with dual-energy technique on a dual source CT scanner.All raw data were transported to the workstation,CT pulmonary angiography (CTPA)images,Lung perfusion blood volume (PBV)images,and Lung Vessels (LV)images were obtained after post-processing.The consistency of CTPA images with LV images in any parts of lung in every normal sub-jects were analyzed and examined by Kappa test.Then sensitivity and specificity of CTPA,lung PBV images,LV images, Lung PBV+LV images in the diagnosis of PE and the positive predictive value (PPV)and negative predictive value (NPV) were calculated respectively.χ2-test or exact probability test were applied to compare the accurate diagnosis rate in detecting PE in different positions of pulmonary artery.Results:CTPA images and LV images had a good consistency in showing the pulmonary arteries of 32 normal subjects in total (K=0.71,P <0.05).Of the 4 software used,the sensitivity of LV soft-ware and Lung PBV+LV was the highest (100%),yet false positive was existed,the PPV was 94.4%、97.1% respective-ly,the specificity of CTPA was the highest (100%),the specificity of Lung PBV software and LV software was 53.8%, 84.6% respectively.Software including CTPA、LV、Lung PBV+ LV in detecting embolisms in pulmonary artery trunks were completely in consistency,no statistic difference was existed in the diagnosis of PE in lobar and segmental pulmonary arteries.However,significant statistical difference was showed in sub-segment or lower pulmonary arteries (χ2 =7.58,P <0.05).As a whole,significant statistical difference was existed in the diagnosis of PE by these three software (χ2 =6.22, P <0.05).Conclusion:Dual source CT with CTPA images and LV images showed a good consistency in displaying pulmo-nary arteries

  6. The Dual Career Family.

    Science.gov (United States)

    Gurtin, Lee

    1980-01-01

    The dual career couple is forced to make a series of choices and compromises that impact the realms of marriage and career. The dilemmas that confront dual career marriages can be overcome only by compromise, accommodation, and mutual understanding on the part of the individuals involved. A revamping of human resources and recruitment programs is…

  7. Self-Dual Gravity

    CERN Document Server

    Krasnov, Kirill

    2016-01-01

    Self-dual gravity is a diffeomorphism invariant theory in four dimensions that describes two propagating polarisations of the graviton and has a negative mass dimension coupling constant. Nevertheless, this theory is not only renormalisable but quantum finite, as we explain. We also collect various facts about self-dual gravity that are scattered across the literature.

  8. Dual Youla parameterization

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2003-01-01

    A different aspect of using the parameterisation of all systems stabilised by a given controller, i.e. the dual Youla parameterisation, is considered. The relation between system change and the dual Youla parameter is derived in explicit form. A number of standard uncertain model descriptions are...

  9. Optical dual self functions

    Institute of Scientific and Technical Information of China (English)

    华建文; 刘立人; 王宁

    1997-01-01

    A recipe to construct the exact dual self-Fourier-Fresnel-transform functions is shown, where the Dirac comb function and transformable even periodic function are used. The mathematical proof and examples are given Then this kind of self-transform function is extended to the feasible optical dual self-transform functions.

  10. Dual doubled geometry

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Riccioni, Fabio; Alvarez-Gaumé, L.

    2011-01-01

    We probe doubled geometry with dual fundamental branes. i.e. solitons. Restricting ourselves first to solitonic branes with more than two transverse directions we find that the doubled geometry requires an effective wrapping rule for the solitonic branes which is dual to the wrapping rule for fundam

  11. Adenosine deaminase polymorphism affects sleep EEG spectral power in a large epidemiological sample.

    Directory of Open Access Journals (Sweden)

    Diego Robles Mazzotti

    Full Text Available Slow wave oscillations in the electroencephalogram (EEG during sleep may reflect both sleep need and intensity, which are implied in homeostatic regulation. Adenosine is strongly implicated in sleep homeostasis, and a single nucleotide polymorphism in the adenosine deaminase gene (ADA G22A has been associated with deeper and more efficient sleep. The present study verified the association between the ADA G22A polymorphism and changes in sleep EEG spectral power (from C3-A2, C4-A1, O1-A2, and O2-A1 derivations in the Epidemiologic Sleep Study (EPISONO sample from São Paulo, Brazil. Eight-hundred individuals were subjected to full-night polysomnography and ADA G22A genotyping. Spectral analysis of the EEG was carried out in all individuals using fast Fourier transformation of the signals from each EEG electrode. The genotype groups were compared in the whole sample and in a subsample of 120 individuals matched according to ADA genotype for age, gender, body mass index, caffeine intake status, presence of sleep disturbance, and sleep-disturbing medication. When compared with homozygous GG genotype carriers, A allele carriers showed higher delta spectral power in Stage 1 and Stages 3+4 of sleep, and increased theta spectral power in Stages 1, 2 and REM sleep. These changes were seen both in the whole sample and in the matched subset. The higher EEG spectral power indicates that the sleep of individuals carrying the A allele may be more intense. Therefore, this polymorphism may be an important source of variation in sleep homeostasis in humans, through modulation of specific components of the sleep EEG.

  12. Research on Dual Control

    Institute of Scientific and Technical Information of China (English)

    Duan Li; Fucai Qian; Peilin Fu

    2005-01-01

    This paper summarizes recent progress by the authors in developing two solution frameworks for dual control. The first solution framework considers a class of dual control problems where there exists a parameter uncertainty in the observation equation of the LQG problem. An analytical active dual control law is derived by a variance minimization approach. The issue of how to determine an optimal degree of active learning is then addressed, thus achieving an optimality for this class of dual control problems. The second solution framework considers a general class of discrete-time LQG problems with unknown parameters in both state and observation equations. The best possible (partial) closed-loop feedback control law is derived by exploring the future nominal posterior probabilities, thus taking into account the effect of future learning when constructing the optimal nominal dual control.

  13. Evidence for an A2/Ra adenosine receptor in the guinea-pig trachea

    Science.gov (United States)

    Brown, C.M.; Collis, M.G.

    1982-01-01

    1 An attempt was made to determine whether the extracellular adenosine receptor that mediates relaxation in the guinea-pig trachea is of the A1/Ri or A2/Ra subtype. 2 Dose-response curves to adenosine and a number of 5′- and N6-substituted analogues were constructed for the isolated guinea-pig trachea, contracted with carbachol. 3 The 5′-substituted analogues of adenosine were the most potent compounds tested, the order of potency being 5′-N-cyclopropylcarboxamide adenosine (NCPCA) > 5′-N-ethylcarboxamide adenosine (NECA) > 2-chloroadenosine > L-N6-phenylisopropyladenosine (L-PIA) > adenosine > D-N6-phenylisopropyladenosine (D-PIA). 4 The difference in potency between the stereoisomers D- and L-PIA on the isolated trachea was at the most five fold. 5 Responses to low doses of adenosine and its analogues were attenuated after treatment with either theophylline or 8-phenyltheophylline. The responses to 2-chloroadenosine were affected to a lesser extent than were those to the other purines. 6 Adenosine transport inhibitors, dipyridamole and dilazep, potentiated responses to adenosine, did not affect those to NCPCA, NECA, L-PIA and D-PIA but significantly reduced the responses to high doses of 2-chloroadenosine. 7 Relaxations evoked by 9-β-D-xylofuranosyladenosine which can activate intracellular but not extracellular adenosine receptors, were attenuated by dipyridamole but unaffected by 8-phenyltheophylline. 8 The results support the existence of an extracellular A2/Ra subtype of adenosine receptor and an intracellular purine-sensitive site, both of which mediate relaxation. PMID:6286021

  14. Effect of phentolamine on the hyperemic response to adenosine in patients with microvascular disease.

    Science.gov (United States)

    Aarnoudse, Wilbert; Geven, Maartje; Barbato, Emanuele; Botman, Kees-joost; De Bruyne, Bernard; Pijls, Nico H J

    2005-12-15

    For accurate measurement of the fractional flow reserve (FFR) of the myocardium, the presence of maximum hyperemia is of paramount importance. It has been suggested that the hyperemic effect of the conventionally used hyperemic stimulus, adenosine, could be submaximal in patients who have microvascular dysfunction and that adding alpha-blocking agents could augment the hyperemic response in these patients. We studied the effect of the nonselective alpha-blocking agent phentolamine, which was administered in addition to adenosine after achieving hyperemia, in patients who had microvascular disease and those who did not. Thirty patients who were referred for percutaneous coronary intervention were selected. Of these 30 patients, 15 had strong indications for microvascular disease and 15 did not. FFR was measured using intracoronary adenosine, intravenous adenosine, and intracoronary papaverine before and after intracoronary administration of the nonselective alpha blocker phentolamine. In patients who did not have microvascular disease, no differences in hyperemic response to adenosine were noted, whether or not alpha blockade was given before adenosine administration; FFR levels before and after phentolamine were 0.76 and 0.75, respectively, using intracoronary adenosine (p = 0.10) and 0.75 and 0.74, respectively, using intravenous adenosine (p = 0.20). In contrast, in patients who had microvascular disease, some increase in hyperemic response was observed after administration of phentolamine; FFR levels decreased from 0.74 to 0.70 using intracoronary adenosine (p = 0.003) and from 0.75 to 0.72 using intravenous adenosine (p = 0.04). Although statistically significant, the observed further decrease in microvascular resistance after addition of phentolamine was small and did not affect clinical decision making in any patient. In conclusion, when measuring FFR, routinely adding an alpha-blocking agent to adenosine does not affect clinical decision making.

  15. Characterization of spontaneous, transient adenosine release in the caudate-putamen and prefrontal cortex.

    Science.gov (United States)

    Nguyen, Michael D; Lee, Scott T; Ross, Ashley E; Ryals, Matthew; Choudhry, Vishesh I; Venton, B Jill

    2014-01-01

    Adenosine is a neuroprotective agent that inhibits neuronal activity and modulates neurotransmission. Previous research has shown adenosine gradually accumulates during pathologies such as stroke and regulates neurotransmission on the minute-to-hour time scale. Our lab developed a method using carbon-fiber microelectrodes to directly measure adenosine changes on a sub-second time scale with fast-scan cyclic voltammetry (FSCV). Recently, adenosine release lasting a couple of seconds has been found in murine spinal cord slices. In this study, we characterized spontaneous, transient adenosine release in vivo, in the caudate-putamen and prefrontal cortex of anesthetized rats. The average concentration of adenosine release was 0.17±0.01 µM in the caudate and 0.19±0.01 µM in the prefrontal cortex, although the range was large, from 0.04 to 3.2 µM. The average duration of spontaneous adenosine release was 2.9±0.1 seconds and 2.8±0.1 seconds in the caudate and prefrontal cortex, respectively. The concentration and number of transients detected do not change over a four hour period, suggesting spontaneous events are not caused by electrode implantation. The frequency of adenosine transients was higher in the prefrontal cortex than the caudate-putamen and was modulated by A1 receptors. The A1 antagonist DPCPX (8-cyclopentyl-1,3-dipropylxanthine, 6 mg/kg i.p.) increased the frequency of spontaneous adenosine release, while the A1 agonist CPA (N(6)-cyclopentyladenosine, 1 mg/kg i.p.) decreased the frequency. These findings are a paradigm shift for understanding the time course of adenosine signaling, demonstrating that there is a rapid mode of adenosine signaling that could cause transient, local neuromodulation.

  16. Adenosine Inhibits the Excitatory Synaptic Inputs to Basal Forebrain Cholinergic, GABAergic and Parvalbumin Neurons in mice

    Directory of Open Access Journals (Sweden)

    Chun eYang

    2013-06-01

    Full Text Available Coffee and tea contain the stimulants caffeine and theophylline. These compounds act as antagonists of adenosine receptors. Adenosine promotes sleep and its extracellular concentration rises in association with prolonged wakefulness, particularly in the basal forebrain (BF region involved in activating the cerebral cortex. However, the effect of adenosine on identified BF neurons, especially non-cholinergic neurons, is incompletely understood. Here we used whole-cell patch-clamp recordings in mouse brain slices prepared from two validated transgenic mouse lines with fluorescent proteins expressed in GABAergic or parvalbumin (PV neurons to determine the effect of adenosine. Whole-cell recordings were made BF cholinergic neurons and from BF GABAergic & PV neurons with the size (>20 µm and intrinsic membrane properties (prominent H-currents corresponding to cortically projecting neurons. A brief (2 min bath application of adenosine (100 μM decreased the frequency but not the amplitude of spontaneous excitatory postsynaptic currents in all groups of BF cholinergic, GABAergic and PV neurons we recorded. In addition, adenosine decreased the frequency of miniature EPSCs in BF cholinergic neurons. Adenosine had no effect on the frequency of spontaneous inhibitory postsynaptic currents in cholinergic neurons or GABAergic neurons with large H-currents but reduced them in a group of GABAergic neurons with smaller H-currents. All effects of adenosine were blocked by a selective, adenosine A1 receptor antagonist, cyclopentyltheophylline (CPT, 1 μM. Adenosine had no postsynaptic effects. Taken together, our work suggests that adenosine promotes sleep by an A1-receptor mediated inhibition of glutamatergic inputs to cortically-projecting cholinergic and GABA/PV neurons. Conversely, caffeine and theophylline promote attentive wakefulness by inhibiting these A1 receptors in BF thereby promoting the high-frequency oscillations in the cortex required for

  17. Adenosine conjugated lipidic nanoparticles for enhanced tumor targeting.

    Science.gov (United States)

    Swami, Rajan; Singh, Indu; Jeengar, Manish Kumar; Naidu, V G M; Khan, Wahid; Sistla, Ramakrishna

    2015-01-01

    Delivering chemotherapeutics by nanoparticles into tumor is impeded majorly by two factors: nonspecific targeting and inefficient penetration. Targeted delivery of anti-cancer agents solely to tumor cells introduces a smart strategy because it enhances the therapeutic index compared with untargeted drugs. The present study was performed to investigate the efficiency of adenosine (ADN) to target solid lipid nanoparticles (SLN) to over expressing adenosine receptor cell lines such as human breast cancer and prostate cancer (MCF-7 and DU-145 cells), respectively. SLN were prepared by emulsification and solvent evaporation process using docetaxel (DTX) as drug and were characterized by various techniques like dynamic light scattering, differential scanning calorimeter and transmission electron microscopy. DTX loaded SLNs were surface modified with ADN, an adenosine receptors ligand using carbodiimide coupling. Conjugation was confirmed using infrared spectroscopy and quantified using phenol-sulfuric acid method. Conjugated SLN were shown to have sustained drug release as compared to unconjugated nanoparticles and drug suspension. Compared with free DTX and unconjugated SLN, ADN conjugated SLN showed significantly higher cytotoxicity of loaded DTX, as evidenced by in vitro cell experiments. The IC50 was 0.41 μg/ml for native DTX, 0.30 μg/ml for unconjugated SLN formulation, and 0.09 μg/ml for ADN conjugated SLN formulation in MCF-7 cell lines. Whereas, in DU-145, there was 2 fold change in IC50 of ADN-SLN as compared to DTX. IC50 was found to be 0.44 μg/ml for free DTX, 0.39 μg/ml for unconjugated SLN and 0.22 μg/ml for ADN-SLN. Annexin assay and cell cycle analysis assay further substantiated the cell cytotoxicity. Fluorescent cell uptake and competitive ligand-receptor binding assay corroborated the receptor mediated endocytosis pathway indicated role of adenosine receptors in internalization of conjugated particles. Pharmacokinetic studies of lipidic

  18. Adenosine triphosphate (ATP) as a possible indicator of extraterrestrial biology

    Science.gov (United States)

    Chappelle, E. W.; Picciolo, G. L.

    1974-01-01

    The ubiquity of adenosine triphosphate (ATP) in terrestrial organisms provides the basis for proposing the assay of this vital metabolic intermediate for detecting extraterrestrial biological activity. If an organic carbon chemistry is present on the planets, the occurrence of ATP is possible either from biosynthetic or purely chemical reactions. However, ATP's relative complexity minimizes the probability of abiogenic synthesis. A sensitive technique for the quantitative detection of ATP was developed using the firefly bioluminescent reaction. The procedure was used successfully for the determination of the ATP content of soil and bacteria. This technique is also being investigated from the standpoint of its application in clinical medicine.

  19. Ribosome-inactivating lectins with polynucleotide:adenosine glycosidase activity.

    Science.gov (United States)

    Battelli, M G; Barbieri, L; Bolognesi, A; Buonamici, L; Valbonesi, P; Polito, L; Van Damme, E J; Peumans, W J; Stirpe, F

    1997-05-26

    Lectins from Aegopodium podagraria (APA), Bryonia dioica (BDA), Galanthus nivalis (GNA), Iris hybrid (IRA) and Sambucus nigra (SNAI), and a new lectin-related protein from Sambucus nigra (SNLRP) were studied to ascertain whether they had the properties of ribosome-inactivating proteins (RIP). IRA and SNLRP inhibited protein synthesis by a cell-free system and, at much higher concentrations, by cells and had polynucleotide:adenosine glycosidase activity, thus behaving like non-toxic type 2 (two chain) RIP. APA and SNAI had much less activity, and BDA and GNA did not inhibit protein synthesis.

  20. 单光源双光路激光并行共焦测量系统设计%Design of laser parallel confocal measurement system with single source and dual beam paths

    Institute of Scientific and Technical Information of China (English)

    余卿; 余晓芬; 崔长彩

    2013-01-01

    To avoid the Talbot effect that is a multiple imaging in the traditional laser parallel confocal measurement, this paper introduces a Digital Micromirror Device(DMD) into the laser parallel confocal measurement to recognize the in-focus image. By taking the DMD as an optical splitting system, it is verified to be a flexible array source, and can not bring Talbot effect into the measurement system. However, the DMD is not an effectual splitting source as it can not converge the split ray effectively. Based on the characteristics of DMD, a laser parallel confocal measurement system with a single source and dual beam paths is constructed by combining a DMD and a Microlens Array(MLA). In this system, the position of in-focus image can be distinguished with the beam path of DMD and the high precision measurement can be completed with the beam path of MLA. The theoretical analysis and the experiment results indicate that the difference between the positions of in-focus images under two kinds of optical detection paths is about 2 μm. Moreover, the influence of Talbot effect on the laser parallel confocal measurement becomes weaker, and the parallel confocal measurement with high precision is achieved.%针对传统激光并行共焦测量过程中存在的泰伯效应,提出将数字微镜器件(DMD)引入激光并行共焦测量系统来正确辨识正焦面的位置.采用了DMD作为光分束器件,从理论上验证了它是一种投影式的阵列光源,对激光分束后不会在光路方向上产生泰伯像;同时,考虑DMD不能对分束后的光线产生会聚作用,并非高效的并行光源分束器件,本文将DMD与微透镜阵列(MLA)结合构建了单光源双光路并行共焦测量系统.该系统利用DMD光路探测正焦面位置,利用微透镜阵列光路进行精确的共焦测量.实验结果表明,两种光路下的正焦面位置仅相差2 μm,在一个泰伯间距范围之内,可以较好地克服泰伯效应对激光并行共焦测量的

  1. Value of dual source CT iodine concentration in the evaluation of pathological grades of esophageal carcinoma%双源CT强化程度与食管癌病理分级的关系

    Institute of Scientific and Technical Information of China (English)

    刘小静; 周胜利; 苗重昌

    2016-01-01

    目的:探讨双源CT碘浓度评估食管癌病理分级的价值。方法回顾性分析经内镜或手术病理证实的60例食管癌患者,其中病理分级为高分化癌17例、中分化癌24例、低分化癌19例。60例均行食管双源CT双能量平扫及双期增强扫描,测量计算食管癌病灶动脉期标准化碘浓度(NIC)、静脉期NIC、动脉期病灶强化程度和静脉期强化程度。采用单因素方差分析比较不同病理分级食管癌患者间NIC及强化程度的差异,采用ROC曲线评价NIC及强化程度鉴别中、高分化食管癌与低分化食管癌的效能。结果高、中、低级别食管癌患者的动脉期NIC值分别为(1.54±0.34)、(1.72±0.50)、(2.10±0.40)mg/ml,静脉期NIC值分别为(1.55±0.52)、(1.80±0.62)、(2.18±0.35)mg/ml,静脉期强化程度分别为(25.65±4.43)、(27.55±6.82)、(30.77±6.38)HU,各组间差异均有统计学意义(P均<0.05);高、中、低级别食管癌患者的动脉期强化程度分别为(14.40±3.91)、(14.26±7.35)、(16.17±6.89) HU,差异无统计学意义(P=0.582)。动脉期NIC、静脉期NIC和静脉期强化程度鉴别中、高分化食管癌与低分化食管癌的ROC下面积分别为0.801、0.817和0.730。结论双源CT测定碘浓度评估食管癌病理分级有一定价值。%Objective To investigate the value of dual source CT iodine concentration in the assessment of pathological grade of esophageal carcinoma. Methods Retrospective review was performed on 60 cases with pathologically⁃confirmed esophageal carcinoma. Among them, 17 tumors were well differentiated, 24 were moderately differentiated and 19 were poorly differentiated. The dual⁃energy plain scan and double phase enhanced scan of dual⁃source CT were performed on all 60 cases. Normalized iodine concentration (NIC) and the enhancement degree of the esophageal carcinoma in the arterial and venous phase were

  2. Structural ordering, morphology and optical properties of amorphous Al{sub x}In{sub 1−x}N thin films grown by plasma-assisted dual source reactive evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, M., E-mail: alizadeh_kozerash@yahoo.com [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ganesh, V. [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Mehdipour, H. [Plasma Nanoscience @ Complex Systems, The University of Sydney, New South Wales 2006 (Australia); Department of Physics, Sharif University of Technology, Tehran 11155-9161 (Iran, Islamic Republic of); Nazarudin, N.F.F.; Goh, B.T.; Shuhaimi, A. [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Rahman, S.A., E-mail: saadah@um.edu.my [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-05-25

    Highlights: • In-rich and Al-rich Al{sub x}In{sub 1−x}N films were grown by plasma-aided reactive evaporation. • The A{sub 1}(LO) phonon mode of the Al-rich films exhibits two-mode behavior. • The band gap of the films was tuned from 1.08 to 2.50 eV. • A bowing parameter of 4.3 eV was calculated for the grown Al{sub x}In{sub 1−x}N films. • The morphology was changed from clusters to uniformly shaped grains by decreasing x. - Abstract: Amorphous aluminum indium nitride (Al{sub x}In{sub 1−x}N) thin films were deposited on quartz substrates by plasma-assisted dual source reactive evaporation system. In-rich (x = 0.10 and 0.18) and Al-rich (x = 0.60 and 0.64) films were prepared by simply varying an AC voltage applied to indium wire. The X-ray-diffraction patterns revealed a small broad peak assigned to Al{sub 0.10}In{sub 0.90}N (0 0 2) plane, but no perceivable peaks assigned to crystalline Al{sub x}In{sub 1−x}N were observed for the films with x = 0.18, 0.60 and 0.64. The morphology of the film was changed from clusters of small grains to uniformly shaped particles with decrease of x. The band gap energy of the films increased from 1.08 eV to 2.50 eV as the Al composition varied from 0.1 to 0.64. Also, Raman results indicated that E{sub 2}(high) and A{sub 1}(LO) peaks of the Al{sub x}In{sub 1−x}N films are remarkably blue-shifted by increasing x and the A{sub 1}(LO) phonon mode of the Al-rich films exhibits two-mode behavior. A bowing parameter of 4.3 eV was obtained for AlInN films. The extrapolated value from bowing equation was 0.85 eV for band gap energy of InN.

  3. Valoración global del corazón en el paciente con transplante cardiaco mediante tomografía computarizada de doble fuente Global evaluation of the heart in heart transplant recipients using dual-source computed tomography

    Directory of Open Access Journals (Sweden)

    G. Bastarrika

    2009-04-01

    Full Text Available La ecocardiografía y la coronariografía convencional son las dos técnicas empleadas en la práctica clínica para el seguimiento de los pacientes con transplante cardiaco. La coronariografía permite diagnosticar la vasculopatía del injerto, pero se trata de un procedimiento invasivo no exento de complicaciones. La tomografía computarizada multicorte convencional es una técnica no invasiva útil para descartar enfermedad coronaria y estudiar la función cardiaca. Sin embargo, debido a su resolución temporal es necesario administrar fármacos betabloqueantes por lo que su utilidad en los pacientes con escasa respuesta a esta medicación, como los transplantados cardiacos, es limitada. La TC de doble fuente permite estudiar las arterias coronarias en todos los individuos con independencia de su frecuencia cardiaca. En el caso que se presenta se demuestra, además, que puede ser una técnica útil para valorar la función y descartar la vasculopatía del injerto en los pacientes con transplante cardiaco.In routine clinical practice surveillance of heart transplant recipients is usually performed using echocardiography and conventional coronary angiography. The latter permits diagnosis and follow-up of coronary allograft vasculopathy. However, this procedure is invasive and is not free of complications. Conventional multislice computed tomography (MSCT has been shown to be a useful non-invasive tool for ruling out coronary artery disease and evaluating cardiac function. However, due to its limited temporal resolution betablocker administration is required, and its usefulness in certain patient populations with restricted response to this medication, such as heart transplant recipients, may therefore be limited. Dual-source CT (DSCT allows evaluation of the coronary arteries in all individuals independent of their heart rate. In the case presented here, we demonstrate that DSCT may be useful for evaluating cardiac function and ruling out

  4. Prospectively Electrocardiogram-Gated High-Pitch Spiral Acquisition Mode Dual-Source CT Coronary Angiography in Patients with High Heart Rates: Comparison with Retrospective Electrocardiogram-Gated Spiral Acquisition Mode

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kai; Ma, Rui; Wang, Li Jun [Dept. of Radiology, Baotou Central Hospital, Baotou (China); Li, Li Gang; Chen, Jiu Hong [CT BM Clinic Marketing, Siemens Healthcare, Beijing (China)

    2012-11-15

    To assess the image quality and effective radiation dose of prospectively electrocardiogram (ECG)-gated high-pitch spiral acquisition mode (flash mode) of dual-source CT (DSCT) coronary angiography (CTCA) in patients with high heart rates (HRs) as compared with retrospectively ECG-gated spiral acquisition mode. Two hundred and sixty-eight consecutive patients (132 female, mean age: 55 {+-} 11 years) with mean HR > 65 beats per minute (bpm) were prospectively included in this study. The patients were divided into two groups. Collection was performed in group A CTCA using flash mode setting at 20-30% of the R-R interval, and retrospectively ECG-gated spiral acquisition mode in group B. The image noise, contrast-to-noise ratio (CNR), image quality scores, effective radiation dose and influencing factors on image quality between the two groups were assessed. There were no significant differences in image quality scores and proportions of non-diagnostic coronary artery segments between two groups (image quality scores: 1.064 {+-} 0.306 [group A] vs. 1.084 {+-} 0.327 [group B], p = 0.063; proportion of non-diagnostic coronary artery segments: segment-based analysis 1.52% (group A) vs. 1.74% (group B), p = 0.345; patient-based analysis 7.5% (group A) vs. 6.7% (group B), p = 0.812). The estimated radiation dose was 1.0 {+-} 0.16 mSv in group A and 7.1 {+-} 1.05 mSv in group B (p = 0.001). In conclusion, in patients with HRs > 65 bpm without cardiac arrhythmia, the prospectively high-pitch spiral-acquisition mode with image-acquired timing set at 20-30% of the R-R interval provides a similar image quality and low rate of non-diagnostic coronary segments to the retrospectively ECG-gated low-pitch spiral acquisition mode, with significant reduction of radiation exposure.

  5. 心电编辑对提高双源CT冠脉图像质量的初步研究%Preliminary application of ECG-editing technique in improving image quality of dual-source CT coronary angiography

    Institute of Scientific and Technical Information of China (English)

    杨立民; 刘成磊; 徐凯

    2012-01-01

    目的:探讨心电编辑在改善双源CT冠脉图像质量中的作用.方法:以冠脉分支为单位,回顾性分析60例心率变异过大或心律失常患者双源CT冠脉成像编辑前后的图像质量,总结不同类型的心电编辑方法.结果:60例心率变异过大或心律失常患者,心率范围为55~269次/min,平均心率(92.8±31.9)次/min,冠脉图像编辑前后的图像质量总评分分别为2.26±1.03、3.5±0.61(t=-17.85,P=0.001);表明编辑前后图像质量的评分有统计学意义,编辑后图像质量明显改善.结论:心电编辑技术可以明显改善心率变异过大或心律失常患者双源CT冠脉成像的图像质量.%Objective:To evaluate the effect of ECG-editing technique on dual-source CT coronary angiography. Methods: Based on per-segment analysis, image quality before and after ECG editing were retrospectively analyzed in 60 patients with heart rate variability or arrhythmia. Different types of ECG editing methods were summarized. Results:In 60 patients without stable sinus rhythm,the heart rate was (55~269) bpm/min. And mean heart rate was (92. 8±31. 9) bpm/min. The over all mean image quality scores before and after ECG editing were (2. 26±1. 03) and (3. 50±0. 61), respectively. There was statistical difference in pre-editing and post-editing reconstructed images quality, suggesting ECG editing significantly improving the image quality ( P <0. 01). Conclusion: ECG editing technique significantly improves image quality of coronary artery in patients with heart rate variability or arrhythmia.

  6. Deep redevelopment of ADVISOR for simulation of pure electric vehicle with dual-source energy storage system%ADVISOR深度二次开发与双能量源纯电动汽车仿真

    Institute of Scientific and Technical Information of China (English)

    张昌利; 张瑾瑾; 刘海波

    2012-01-01

    通过ADVISOR软件深度二次开发,建立蓄电池-超级电容双能量源纯电动汽车的仿真模型及仿真软件平台,利用软件平台对双能量源纯电动汽车的整车经济性能和动力性能进行仿真分析.研究结果表明:与原ADVISOR软件相比,深度二次开发后的仿真软件平台使用XML配置文件在仿真框架、仿真模型和仿真数据之间建立弱耦合关系,利于将软件平台向其他电动汽车车型移植;使用.NET与MATLAB混合编程充分发挥了2种工具的各自优势,并通过仿真融合使软件平台的界面具有更好的集成性和友好性;该软件平台能够更好地为双能量源纯电动汽车的车辆零部件选型、参数匹配与优化、实验样车研发等工作提供仿真支持.%Through the deep redevelopment of ADVISOR software, the simulation models of pure electric vehicle (PEV) with dual-source energy storage system (DESS) composed of batteries and ultra-capacitors, as well as the simulation software platform, were established. Economical efficiency and the dynamic property of the PEV with DESS were analyzed through simulation experiment on this platform. The results show that compared with ADVISOR software, there are several superiorities of this simulation software platform. Firstly, this platform establishes a lower coupling relationship among the simulation framework, the simulation model and the simulation data with an XML configuration file, and thus it is more convenient to transplant this platform to other types of electric vehicles. Secondly, it takes the advantages of .NET and MATLAB by mixed programming with both tools. Thirdly, the graphic user interface of this platform is more integrated and friendlier. In conclusion, this platform can support the simulation works for electric vehicle development, such as the selection of vehicle components, the match and optimization of vehicle parameters, and the development of vehicle prototypes, etc.

  7. 基于Random Walks算法的心脏双源CT左心房分割%Study of left atrium segmentation in dual source CT image with random walks algorithms

    Institute of Scientific and Technical Information of China (English)

    何昌保; 马秀丽; 余长明

    2016-01-01

    For dual source CT image with contrast media,due to heart soft tissue density and contrast media uneven distribution result in the CT value of heart tissues uneven and boundary fuzzy,taking a single image segmentation algorithm is too difficult to obtain satisfactory results,so morphological reconstruction and random walks hybrid method is proposed in this paper.Firstly,we used morphological reconstruction operation on image smoothing filtering, which makes the heart cavity gray information convergence and gray level differences with the surrounding tissue and get the left atrium area with the fuzzy boundary;Then the random walks algorithm sets the seed points for each region of the image,and gives the weight of each side,and takes the weight of the edge as the transfer probability.For each unlabeled point is calculated from the point of first arrival probability of seed points.Finally,according to the first hit probability to choose the maximum that a class as belonging to the class,attribute of the unlabeled points and finally get the accurate left atrial.%针对在传统的CT介入式治疗过程中,胸腔中软组织较多软组织的厚度和注射的造影剂在心脏中呈现的不均匀分布,导致在采用CT成像的图像中胸腔内部各组织之间存在边界模糊或者确实等状况,本文提出一种采用形态重构和随机行走相结合的分割方法。首先利用形态学开闭运算对图像进行化简,并使得心脏 CT腔体边界分离,进而使得各个组织组织分离,再结合Random walks算法。从而使得不需要标记太多种子点的情况下提高了分割的速度和准确性,实验证明该方法能够达到预期的目标。

  8. Dual Source CT Angiography in Diagnosis and Treatment for Aneurvsms of Willis Circle%双源CT血管成像在Willis环区动脉瘤诊断及治疗中的应用

    Institute of Scientific and Technical Information of China (English)

    沈国鑫; 庾君毅; 史跃; 王安明

    2011-01-01

    目的:探讨双源CT血管成像(DSCTA)在Willis环区动脉瘤的诊断、分型及介入栓塞治疗中的临床应用价值.方法:术前采用DSCTA检查筛选颅内动脉瘤患者26例(33个).采用Seldinger技术,在DSA引导下行全脑血管造影,了解动脉瘤位置、形态、大小,测量瘤颈及瘤体直径;再根据不同的解剖学形态选用不同的介入栓塞方法治疗.结果:术前DSCAT和DSA检查对颅内动脉瘤的大小、位置、形状显示一致.26例患者共33个动脉瘤均成功栓塞,完全栓塞18个,占54.54%;栓塞程度在95%以上12个,占36.36%;不完全栓塞3个,占9.09%.结论:DSCTA检查和DSA全脑血管检查可提供颅内动脉瘤的位置、形态、大小等影像解剖学资料,为动脉瘤的临床分类和治疗方法的选择提供依据.%Objective: To evaluate the clinical value of dual source CT angiography (DSCTA) in the diagnosis, classification and interventional embolisation treatment for aneurysm of Willis circle.Methods:26cases with intracranial aneurysms were screened in preoperation by DSCTA.Preoperative cerebral angiography under the guidance of the DSA was used by the Seldinger technique, the analysis and research of the information could be assisted to comprehend the location, shape, size of aneurysm, the diameter of aneurysm neck and body was measured, then appropriate interventional therapy was selected according to different anatomical patterns.Results :33 intracranial aneurysms in 26 patients were successfully embolized.Complete embolism was achieved in 18 cases (54.54%), embolismed over 95% in 12 (36.36%), partial embolism in 3 aneurysms( 9.09% ).Conclusions:Preoperative examination by DSCTA and DSA can provide the basis for aneurysm treatment, reduce blindness and shorten the treatment time.

  9. Dual practitioners are as engaged in their primary job as their senior colleagues

    DEFF Research Database (Denmark)

    Socha, Karolina; Bech, Mickael

    2012-01-01

    Introduction: Dual practice – the combination of a public hospital job with a job held in private health care – is often a source of controversy. Physicians involved in dual practice (dual practitioners) are believed to provide less work input in their public employment than physicians who...... is significantly different from that suggested in the current debate. The findings suggest that the dual practice implications for the functioning of the public health-care system are less problematic than expected....

  10. Treatment of paroxysmal supraventricular tachycardia with intravenous injection of adenosine triphosphate.

    OpenAIRE

    Saito, D.; Ueeda, M; Abe, Y.; Tani, H; Nakatsu, T.; Yoshida, H.; Haraoka, S; Nagashima, H

    1986-01-01

    Intravenous adenosine triphosphate rapidly terminated all 11 episodes of paroxysmal supraventricular tachycardia in 10 patients. Eight patients reported side effects but these resolved within 20 seconds and did not require treatment. Adenosine triphosphate is a suitable agent for the rapid termination of paroxysmal supraventricular tachycardia.

  11. The ischemic preconditioning effect of adenosine in patients with ischemic heart disease

    Directory of Open Access Journals (Sweden)

    Berglund Margareta

    2009-11-01

    Full Text Available Abstract Introduction In vivo and in vitro evidence suggests that adenosine and its agonists play key roles in the process of ischemic preconditioning. The effects of low-dose adenosine infusion on ischemic preconditioning have not been thoroughly studied in humans. Aims We hypothesised that a low-dose adenosine infusion could reduce the ischemic burden evoked by physical exercise and improve the regional left ventricular (LV systolic function. Materials and methods We studied nine severely symptomatic male patients with severe coronary artery disease. Myocardial ischemia was induced by exercise on two separate occasions and quantified by Tissue Doppler Echocardiography. Prior to the exercise test, intravenous low-dose adenosine or placebo was infused over ten minutes according to a randomized, double blind, cross-over protocol. The LV walls were defined as ischemic if a reduction, no increment, or an increment of Results PSV increased from baseline to maximal exercise in non-ischemic walls both during placebo (P = 0.0001 and low-dose adenosine infusion (P = 0.0009. However, in the ischemic walls, PSV increased only during low-dose adenosine infusion (P = 0.001, while no changes in PSV occurred during placebo infusion (P = NS. Conclusion Low-dose adenosine infusion reduced the ischemic burden and improved LV regional systolic function in the ischemic walls of patients with exercise-induced myocardial ischemia, confirming that adenosine is a potential preconditioning agent in humans.

  12. Genetically Controlled Upregulation of Adenosine A(1) Receptor Expression Enhances the Survival of Primary Cortical Neurons

    NARCIS (Netherlands)

    Serchov, Tsvetan; Atas, Hasan-Cem; Normann, Claus; van Calker, Dietrich; Biber, Knut

    2012-01-01

    Adenosine has a key endogenous neuroprotective role in the brain, predominantly mediated by the adenosine A(1) receptor (A(1)R). This has been mainly explored using pharmacological tools and/or receptor knockout mice strains. It has long been suggested that the neuroprotective effects of A(1)R are i

  13. Nafion-CNT coated carbon-fiber microelectrodes for enhanced detection of adenosine.

    Science.gov (United States)

    Ross, Ashley E; Venton, B Jill

    2012-07-07

    Adenosine is a neuromodulator that regulates neurotransmission. Adenosine can be monitored using fast-scan cyclic voltammetry at carbon-fiber microelectrodes and ATP is a possible interferent in vivo because the electroactive moiety, adenine, is the same for both molecules. In this study, we investigated carbon-fiber microelectrodes coated with Nafion and carbon nanotubes (CNTs) to enhance the sensitivity of adenosine and decrease interference by ATP. Electrodes coated in 0.05 mg mL(-1) CNTs in Nafion had a 4.2 ± 0.2 fold increase in current for adenosine, twice as large as for Nafion alone. Nafion-CNT electrodes were 6 times more sensitive to adenosine than ATP. The Nafion-CNT coating did not slow the temporal response of the electrode. Comparing different purine bases shows that the presence of an amine group enhances sensitivity and that purines with carbonyl groups, such as guanine and hypoxanthine, do not have as great an enhancement after Nafion-CNT coating. The ribose group provides additional sensitivity enhancement for adenosine over adenine. The Nafion-CNT modified electrodes exhibited significantly more current for adenosine than ATP in brain slices. Therefore, Nafion-CNT modified electrodes are useful for sensitive, selective detection of adenosine in biological samples.

  14. The effect of circulating adenosine on cerebral haemodynamics and headache generation in healthy subjects

    DEFF Research Database (Denmark)

    Birk, S; Petersen, K.A.; Kruuse, Christina Rostrup

    2005-01-01

    been investigated in man and reports regarding the effect of intravenous adenosine on cerebral blood flow are conflicting. Twelve healthy participants received adenosine 80, 120 microg kg(-1) min(-1) and placebo intravenously for 20 min, in a double-blind, three-way, crossover, randomized design...

  15. Different Modulating Effects of Adenosine on Neonatal and Adult Polymorphonuclear Leukocytes

    Directory of Open Access Journals (Sweden)

    Pei-Chen Hou

    2012-01-01

    Full Text Available Polymorphonuclear leukocytes (PMNs are the major leukocytes in the circulation and play an important role in host defense. Intact PMN functions include adhesion, migration, phagocytosis, and reactive oxygen species (ROS release. It has been known for a long time that adenosine can function as a modulator of adult PMN functions. Neonatal plasma has a higher adenosine level than that of adults; however, little is known about the modulating effects of adenosine on neonatal PMNs. The aim of this study was to investigate the effects of adenosine on neonatal PMN functions. We found that neonatal PMNs had impaired adhesion, chemotaxis, and ROS production abilities, but not phagocytosis compared to adult PMNs. As with adult PMNs, adenosine could suppress the CD11b expressions of neonatal PMNs, but had no significant suppressive effect on phagocytosis. In contrast to adult PMNs, adenosine did not significantly suppress chemotaxis and ROS production of neonatal PMNs. This may be due to impaired phagocyte reactions and a poor neonatal PMN response to adenosine. Adenosine may not be a good strategy for the treatment of neonatal sepsis because of impaired phagocyte reactions and poor response.

  16. Adenosine signaling and the energetic costs of induced immunity.

    Directory of Open Access Journals (Sweden)

    Brian P Lazzaro

    2015-04-01

    Full Text Available Life history theory predicts that trait evolution should be constrained by competing physiological demands on an organism. Immune defense provides a classic example in which immune responses are presumed to be costly and therefore come at the expense of other traits related to fitness. One strategy for mitigating the costs of expensive traits is to render them inducible, such that the cost is paid only when the trait is utilized. In the current issue of PLOS Biology, Bajgar and colleagues elegantly demonstrate the energetic and life history cost of the immune response that Drosophila melanogaster larvae induce after infection by the parasitoid wasp Leptopilina boulardi. These authors show that infection-induced proliferation of defensive blood cells commands a diversion of dietary carbon away from somatic growth and development, with simple sugars instead being shunted to the hematopoetic organ for rapid conversion into the raw energy required for cell proliferation. This metabolic shift results in a 15% delay in the development of the infected larva and is mediated by adenosine signaling between the hematopoietic organ and the central metabolic control organ of the host fly. The adenosine signal thus allows D. melanogaster to rapidly marshal the energy needed for effective defense and to pay the cost of immunity only when infected.

  17. Adenosine Deaminase Deficiency - More Than Just an Immunodeficiency

    Directory of Open Access Journals (Sweden)

    Kathryn Victoria Whitmore

    2016-08-01

    Full Text Available Adenosine deaminase (ADA deficiency is best known as a form of severe combined immunodeficiency (SCID which results from mutations in the gene encoding adenosine deaminase. Affected patients present with clinical and immunological manifestations typical of a severe combined immunodeficiency. Therapies are currently available that can that target these immunological disturbances and treated patients show varying degrees of clinical improvement. However, there is now a growing body of evidence that deficiency of ADA has significant impact on non-immunological organ systems. This review will outline the impact of ADA deficiency on various organ systems, starting with the well understood immunological abnormalities. We will discuss possible pathogenic mechanisms and also highlight ways in which current treatments could be improved. In doing so, we aim to present ADA deficiency as more than an immunodeficiency and suggest that it should be recognized as a systemic metabolic disorder that affects multiple organ systems. Only by fully understanding ADA deficiency and its manifestations in all organ systems can we aim to deliver therapies that will correct all the clinical consequences.

  18. Methylthioadenosine reprograms macrophage activation through adenosine receptor stimulation.

    Directory of Open Access Journals (Sweden)

    Peter A Keyel

    Full Text Available Regulation of inflammation is necessary to balance sufficient pathogen clearance with excessive tissue damage. Central to regulating inflammation is the switch from a pro-inflammatory pathway to an anti-inflammatory pathway. Macrophages are well-positioned to initiate this switch, and as such are the target of multiple therapeutics. One such potential therapeutic is methylthioadenosine (MTA, which inhibits TNFα production following LPS stimulation. We found that MTA could block TNFα production by multiple TLR ligands. Further, it prevented surface expression of CD69 and CD86 and reduced NF-KB signaling. We then determined that the mechanism of this action by MTA is signaling through adenosine A2 receptors. A2 receptors and TLR receptors synergized to promote an anti-inflammatory phenotype, as MTA enhanced LPS tolerance. In contrast, IL-1β production and processing was not affected by MTA exposure. Taken together, these data demonstrate that MTA reprograms TLR activation pathways via adenosine receptors to promote resolution of inflammation.

  19. Novel trypanocidal analogs of 5'-(methylthio)-adenosine.

    Science.gov (United States)

    Sufrin, Janice R; Spiess, Arthur J; Marasco, Canio J; Rattendi, Donna; Bacchi, Cyrus J

    2008-01-01

    The purine nucleoside 5'-deoxy-5'-(hydroxyethylthio)-adenosine (HETA) is an analog of the polyamine pathway metabolite 5'-deoxy-5'-(methylthio)-adenosine (MTA). HETA is a lead structure for the ongoing development of selectively targeted trypanocidal agents. Thirteen novel HETA analogs were synthesized and examined for their in vitro trypanocidal activities against bloodstream forms of Trypanosoma brucei brucei LAB 110 EATRO and at least one drug-resistant Trypanosoma brucei rhodesiense clinical isolate. New compounds were also assessed in a cell-free assay for their activities as substrates of trypanosome MTA phosphorylase. The most potent analog in this group was 5'-deoxy-5'-(hydroxyethylthio)-tubercidin, whose in vitro cytotoxicity (50% inhibitory concentration [IC50], 10 nM) is 45 times greater than that of HETA (IC50, 450 nM) against pentamidine-resistant clinical isolate KETRI 269. Structure-activity analyses indicate that the enzymatic cleavage of HETA analogs by trypanosome MTA phosphorylase is not an absolute requirement for trypanocidal activity. This suggests that additional biochemical mechanisms are associated with the trypanocidal effects of HETA and its analogs.

  20. Adenosine Amine Congener as a Cochlear Rescue Agent

    Directory of Open Access Journals (Sweden)

    Srdjan M. Vlajkovic

    2014-01-01

    Full Text Available We have previously shown that adenosine amine congener (ADAC, a selective A1 adenosine receptor agonist, can ameliorate noise- and cisplatin-induced cochlear injury. Here we demonstrate the dose-dependent rescue effects of ADAC on noise-induced cochlear injury in a rat model and establish the time window for treatment. Methods. ADAC (25–300 μg/kg was administered intraperitoneally to Wistar rats (8–10 weeks old at intervals (6–72 hours after exposure to traumatic noise (8–16 kHz, 110 dB sound pressure level, 2 hours. Hearing sensitivity was assessed using auditory brainstem responses (ABR before and 12 days after noise exposure. Pharmacokinetic studies investigated ADAC concentrations in plasma after systemic (intravenous administration. Results. ADAC was most effective in the first 24 hours after noise exposure at doses >50 μg/kg, providing up to 21 dB protection (averaged across 8–28 kHz. Pharmacokinetic studies demonstrated a short (5 min half-life of ADAC in plasma after intravenous administration without detection of degradation products. Conclusion. Our data show that ADAC mitigates noise-induced hearing loss in a dose- and time-dependent manner, but further studies are required to establish its translation as a clinical otological treatment.

  1. Reconstruction of the adenosine system by bone marrow-derived mesenchymal stem cell transplantation

    Institute of Scientific and Technical Information of China (English)

    Huicong Kang; Qi Hu; Xiaoyan Liu; Yinhe Liu; Feng Xu; Xiang Li; Suiqiang Zhu

    2012-01-01

    In the present study, we transplanted bone marrow-derived mesenchymal stem cells into the CA3 area of the hippocampus of chronic epilepsy rats kindled by lithium chloride-pilocarpine. Immunofluorescence and western blotting revealed an increase in adenosine A1 receptor expression and a decrease in adenosine A2a receptor expression in the brain tissues of epileptic rats 3 months after transplantation. Moreover, the imbalance in the A1 adenosine receptor/A2a adenosine receptor ratio was improved. Electroencephalograms showed that frequency and amplitude of spikes in the hippocampus and frontal lobe were reduced. These results suggested that mesenchymal stem cell transplantation can reconstruct the normal function of the adenosine system in the brain and greatly improve epileptiform discharges.

  2. Adenosine activates brown adipose tissue and recruits beige adipocytes via A2A receptors

    DEFF Research Database (Denmark)

    Gnad, Thorsten; Scheibler, Saskia; von Kügelgen, Ivar

    2014-01-01

    hamster or rat. However, the role of adenosine in human BAT is unknown. Here we show that adenosine activates human and murine brown adipocytes at low nanomolar concentrations. Adenosine is released in BAT during stimulation of sympathetic nerves as well as from brown adipocytes. The adenosine A2A...... of A2A receptors or injection of lentiviral vectors expressing the A2A receptor into white fat induces brown-like cells-so-called beige adipocytes. Importantly, mice fed a high-fat diet and treated with an A2A agonist are leaner with improved glucose tolerance. Taken together, our results demonstrate...... that adenosine-A2A signalling plays an unexpected physiological role in sympathetic BAT activation and protects mice from diet-induced obesity. Those findings reveal new possibilities for developing novel obesity therapies....

  3. Comparison of exogenous adenosine and voluntary exercise on human skeletal muscle perfusion and perfusion heterogeneity

    DEFF Research Database (Denmark)

    Heinonen, Ilkka H.A.; Kemppainen, Jukka; Kaskinoro, Kimmo;

    2010-01-01

    femoral artery infusion of adenosine (1 mg * min(-1) * litre thigh volume(-1)), which has previously been shown to induce maximal whole thigh blood flow of ~8 L/min. This response was compared to the blood flow induced by moderate-high intensity one-leg dynamic knee extension exercise. Adenosine increased...... muscle. Additionally, it remains to be determined what proportion of adenosine-induced flow elevation is specifically directed to muscle only. In the present study we measured thigh muscle capillary nutritive blood flow in nine healthy young men using positron emission tomography at rest and during...... muscle blood flow on average to 40 +/- 7 ml. min(-1) per 100g(-1) of muscle and an aggregate value of 2.3 +/- 0.6 L * min(-1) for the whole thigh musculature. Adenosine also induced a substantial change in blood flow distribution within individuals. Muscle blood flow during adenosine infusion...

  4. Interstitial and plasma adenosine stimulate nitric oxide and prostacyclin formation in human skeletal muscle

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan Peter; Thaning, Pia;

    2010-01-01

    One major unresolved issue in muscle blood flow regulation is that of the role of circulating versus interstitial vasodilatory compounds. The present study determined adenosine-induced formation of NO and prostacyclin in the human muscle interstitium versus in femoral venous plasma to elucidate....... In young healthy humans, microdialysate was collected at rest, during arterial infusion of adenosine, and during interstitial infusion of adenosine through microdialysis probes inserted into musculus vastus lateralis. Muscle interstitial NO and prostacyclin increased with arterial and interstitial infusion...... levels. These findings provide novel insight into the role of adenosine in skeletal muscle blood flow regulation and vascular function by revealing that both interstitial and plasma adenosine have a stimulatory effect on NO and prostacyclin formation. In addition, both skeletal muscle and microvascular...

  5. Dual Axis Light Sensor for Tracking Sun

    Science.gov (United States)

    Shibata, Miki; Tambo, Toyokazu

    We have developed convenient light sensors to control a platform of solar cell panel. Dual axis light sensor in the present paper has structure of 5 PD (photodiode) light sensor which is composed of 5 photodiodes attached on a frustum of pyramid(1). Light source can be captured in front of the sensor by rotating the X and Y axis as decreasing the output deviation between two pairs of outside photodiodes. We here report the mechanism of sun tacking using the dual axis 5 PD light sensor and the fundamental results performed in the dark room.

  6. 2-(1-Hexyn-1-yl)adenosine-induced intraocular hypertension is mediated via K+ channel opening through adenosine A2A receptor in rabbits.

    Science.gov (United States)

    Konno, Takashi; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2005-08-22

    The present study was performed to clarify the mechanism of change in intraocular pressure by 2-(1-hexyn-1-yl)adenosine (2-H-Ado), a selective adenosine A2 receptor agonist, in rabbits. 2-H-Ado (0.1%, 50 microl)-induced ocular hypertension (E(max): 7.7 mm Hg) was inhibited by an adenosine A2A receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine, ATP-sensitive K+ channel blocker glibenclamide or 5-hydroxydecanoic acid, but not by an adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine, an adenosine A2B receptor antagonist alloxazine or a cyclooxygenase inhibitor indomethacin. The outflow facility induced by 2-H-Ado seems to be independent of increase in intraocular pressure or ATP-sensitive K+ channel. In contrast, the recovery rate in intraocular pressure decreased by hypertonic saline was accelerated by 2-H-Ado, and this response was dependent on ATP-sensitive K+ channel. These results suggest that 2-H-Ado-induced ocular hypertension is mediated via K+ channel opening through adenosine A2A receptor, and this is probably due to aqueous formation, but independent of change in outflow facility or prostaglandin production.

  7. Autophagy occurs within an hour of adenosine triphosphate treatment after nerve cell damage:the neuroprotective effects of adenosine triphosphate against apoptosis

    Institute of Scientific and Technical Information of China (English)

    Na Lu; Baoying Wang; Xiaohui Deng; Honggang Zhao; Yong Wang; Dongliang Li

    2014-01-01

    After hypoxia, ischemia, or inlfammatory injuries to the central nervous system, the damaged cells release a large amount of adenosine triphosphate, which may cause secondary neuronal death. Autophagy is a form of cell death that also has neuroprotective effects. Cell Counting Kit assay, monodansylcadaverine staining, lfow cytometry, western blotting, and real-time PCR were used to determine the effects of exogenous adenosine triphosphate treatment at different concentrations (2, 4, 6, 8, 10 mmol/L) over time (1, 2, 3, and 6 hours) on the apoptosis and autophagy of SH-SY5Y cells. High concentrations of extracellular adenosine triphosphate induced autophagy and apoptosis of SH-SY5Y cells. The enhanced autophagy ifrst appeared, and peaked at 1 hour after treatment with adenosine triphosphate. Cell apoptosis peaked at 3 hours, and persisted through 6 hours. With prolonged exposure to the adenosine triphosphate treatment, the fraction of apoptotic cells increased. These data suggest that the SH-SY5Y neural cells initiated autophagy against apoptosis within an hour of adenosine triphosphate treatment to protect themselves against injury.

  8. Dual coil ignition system

    Energy Technology Data Exchange (ETDEWEB)

    Huberts, Garlan J.; Qu, Qiuping; Czekala, Michael Damian

    2017-03-28

    A dual coil ignition system is provided. The dual coil ignition system includes a first inductive ignition coil including a first primary winding and a first secondary winding, and a second inductive ignition coil including a second primary winding and a second secondary winding, the second secondary winding connected in series to the first secondary winding. The dual coil ignition system further includes a diode network including a first diode and a second diode connected between the first secondary winding and the second secondary winding.

  9. Hypocretin/orexin antagonism enhances sleep-related adenosine and GABA neurotransmission in rat basal forebrain.

    Science.gov (United States)

    Vazquez-DeRose, Jacqueline; Schwartz, Michael D; Nguyen, Alexander T; Warrier, Deepti R; Gulati, Srishti; Mathew, Thomas K; Neylan, Thomas C; Kilduff, Thomas S

    2016-03-01

    Hypocretin/orexin (HCRT) neurons provide excitatory input to wake-promoting brain regions including the basal forebrain (BF). The dual HCRT receptor antagonist almorexant (ALM) decreases waking and increases sleep. We hypothesized that HCRT antagonists induce sleep, in part, through disfacilitation of BF neurons; consequently, ALM should have reduced efficacy in BF-lesioned (BFx) animals. To test this hypothesis, rats were given bilateral IgG-192-saporin injections, which predominantly targets cholinergic BF neurons. BFx and intact rats were then given oral ALM, the benzodiazepine agonist zolpidem (ZOL) or vehicle (VEH) at lights-out. ALM was less effective than ZOL at inducing sleep in BFx rats compared to controls. BF adenosine (ADO), γ-amino-butyric acid (GABA), and glutamate levels were then determined via microdialysis from intact, freely behaving rats following oral ALM, ZOL or VEH. ALM increased BF ADO and GABA levels during waking and mixed vigilance states, and preserved sleep-associated increases in GABA under low and high sleep pressure conditions. ALM infusion into the BF also enhanced cortical ADO release, demonstrating that HCRT input is critical for ADO signaling in the BF. In contrast, oral ZOL and BF-infused ZOL had no effect on ADO levels in either BF or cortex. ALM increased BF ADO (an endogenous sleep-promoting substance) and GABA (which is increased during normal sleep), and required an intact BF for maximal efficacy, whereas ZOL blocked sleep-associated BF GABA release, and required no functional contribution from the BF to induce sleep. ALM thus induces sleep by facilitating the neural mechanisms underlying the normal transition to sleep.

  10. Involvement of adenosine A2a receptor in intraocular pressure decrease induced by 2-(1-octyn-1-yl)adenosine or 2-(6-cyano-1-hexyn-1-yl)adenosine.

    Science.gov (United States)

    Konno, Takashi; Murakami, Akira; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2005-04-01

    The aim of the present study is to clarify the mechanism for the decrease in intraocular pressure by 2-alkynyladenosine derivatives in rabbits. The receptor binding analysis revealed that 2-(1-octyn-1-yl)adenosine (2-O-Ado) and 2-(6-cyano-1-hexyn-1-yl)adenosine (2-CN-Ado) selectively bound to the A(2a) receptor with a high affinity. Ocular hypotensive responses to 2-O-Ado and 2-CN-Ado were inhibited by the adenosine A(2a)-receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine (CSC), but not by the adenosine A(1)-receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) or the adenosine A(2b)-receptor antagonist alloxazine. In addition, 2-O-Ado and 2-CN-Ado caused an increase in outflow facility, which was inhibited by CSC, but not by DPCPX or alloxazine. Moreover, 2-O-Ado and 2-CN-Ado increased cAMP in the aqueous humor, and the 2-O-Ado-induced an increase in cAMP was inhibited by CSC. These results suggest that 2-O-Ado and 2-CN-Ado reduced intraocular pressure via an increase in outflow facility. The ocular hypotension may be mainly mediated through the activation of adenosine A(2a) receptor, although a possible involvement of adenosine A(1) receptor cannot be completely ruled out. 2-O-Ado and 2-CN-Ado are useful lead compounds for the treatment of glaucoma.

  11. Inhibition by adenosine of histamine and leukotriene release from human basophils.

    Science.gov (United States)

    Peachell, P T; Lichtenstein, L M; Schleimer, R P

    1989-06-01

    Adenosine inhibited the release of histamine and leukotriene C4 (LTC4) from immunologically-activated basophils in a dose-dependent manner. Structural congeners of adenosine also attenuated the elaboration of these two mediators from stimulated basophils and a rank order of potency for the inhibition was observed following the sequence 2-chloroadenosine greater than or equal to N-ethylcarboxamidoadenosine (NECA) greater than adenosine greater than or equal to R-phenylisopropyladenosine (R-PIA) greater than or equal to S-PIA. These same nucleosides modulated the generation of LTC4 more potently than the release of histamine. A number of methylxanthines, which are antagonists of cell surface adenosine receptors, reversed the inhibition by adenosine and its congeners of the release of both histamine and LTC4 to varying extents. Dipyridamole and nitrobenzylthioinosine (NBTI), agents that block the intracellular uptake of adenosine, antagonized the inhibition of histamine release by adenosine (and 2-chloroadenosine) but failed to reverse the attenuation of LTC4 generation by the nucleoside. These same uptake blockers were unable to antagonize the inhibitory effects of NECA on either histamine or LTC4 release. In purified basophils, NECA and R-PIA, and in that order of decreasing reactivity, increased total cell cyclic adenosine monophosphate (cAMP) levels and inhibited the stimulated release of mediators. In total, these results suggest that the basophil possesses a cell surface adenosine receptor which, on the basis of both pharmacological and biochemical criteria, most closely conforms to an A2/Ra-like receptor. However, in addition to an interaction at the cell surface, studies with agents that block the intracellular uptake of adenosine suggest that the nucleoside may also exert intracellular effects when countering the release of histamine (but not LTC4).

  12. Sawhorse waveform voltammetry for selective detection of adenosine, ATP, and hydrogen peroxide.

    Science.gov (United States)

    Ross, Ashley E; Venton, B Jill

    2014-08-05

    Fast-scan cyclic voltammetry (FSCV) is an electrochemistry technique which allows subsecond detection of neurotransmitters in vivo. Adenosine detection using FSCV has become increasingly popular but can be difficult because of interfering agents which oxidize at or near the same potential as adenosine. Triangle shaped waveforms are traditionally used for FSCV, but modified waveforms have been introduced to maximize analyte sensitivity and provide stability at high scan rates. Here, a modified sawhorse waveform was used to maximize the time for adenosine oxidation and to manipulate the shapes of cyclic voltammograms (CVs) of analytes which oxidize at the switching potential. The optimized waveform consists of scanning at 400 V/s from -0.4 to 1.35 V and holding briefly for 1.0 ms followed by a ramp back down to -0.4 V. This waveform allows the use of a lower switching potential for adenosine detection. Hydrogen peroxide and ATP also oxidize at the switching potential and can interfere with adenosine measurements in vivo; however, their CVs were altered with the sawhorse waveform and they could be distinguished from adenosine. Principal component analysis (PCA) was used to determine that the sawhorse waveform was better than the triangle waveform at discriminating between adenosine, hydrogen peroxide, and ATP. In slices, mechanically evoked adenosine was identified with PCA and changes in the ratio of ATP to adenosine were observed after manipulation of ATP metabolism by POM-1. The sawhorse waveform is useful for adenosine, hydrogen peroxide, and ATP discrimination and will facilitate more confident measurements of these analytes in vivo.

  13. 75 FR 8981 - Prospective Grant of Exclusive License: Treatment of Glaucoma by Administration of Adenosine A3...

    Science.gov (United States)

    2010-02-26

    ... Glaucoma by Administration of Adenosine A3 Antagonists AGENCY: National Institutes of Health, Public Health.../092,292, entitled ``A3 Adenosine Receptor Antagonists,'' filed July 10, 1998 , PCT Application PCT/US99/ 15562, entitled''A3 Adenosine Receptor Antagonists,'' filed July 2, 1999 , U.S. Patent...

  14. 胃左动脉参与肝细胞癌供血的双源CT血管成像研究%Evaluation of hepatocellular carcinoma supplied by the left gastric artery with dual-source CT angiography

    Institute of Scientific and Technical Information of China (English)

    陈光文; 涂诗琦; 陈加源; 赵黎明

    2012-01-01

    Objective:To investigate the incidence and influential factors of hepatocellular carcinoma (HCC) supplied by the left gastric artery. Methods:91 patients with HCC in left lobe were prospectively included in the study. Standardized dual source CT (DSCT) multi phases acquisition was performed for all patients. Thin slice source images were reconstruc ted using techniques ol multi planar reconstruction, curved planar reconstruction,maximum intensity projection and volume rendering to display the left gastric artery. The images were interpreted by three experienced abdominal radiologists. The in cidence of HCC fed by LGA and factors like the size, location, pseudocapsule of HCC lesions and previous history of transarterial chemoembolization (TACE) therapy were analyzed. Results:There were 23 (22. 1 %) cases supplied by LGA in 91 patients with a total of 104 HCC lesions,while 19 lesions were type macro mass compared with 4 lesions as type nodus, 22 lesions invaded Glisson capsule and 17 lesions had previous history of TACE therapy. All lesions had no unbroken pseud ocapsule. LGA participated in HCC blood supply by left lobe hepatic artery (n=3) and accessory left lobe hepatic artery (n=5) originated from LGA,as well as branch direct supplying the lesions (n=15). Conclusion:LGA is common extrahe patic collateral artery of left lobe HCC and the presence is significantly correlated with the tumor size,the location,the sta tus of pseudocapsule and history of TACE therapy of HCC lesion.%目的:探讨胃左动脉(LGA)参与肝细胞癌(HCC)供血的影响因素.方法:采用双源CT对91例左叶HCC患者进行血管成像扫描,采用MPR、CPR、MIP、VR等后处理技术重建LGA.分析LGA参与HCC供血与病灶大小、位置、假包膜的完整性及接受经导管动脉化疗栓塞(TACE)治疗的关系.结果:91例患者共计104个HCC病灶,23个病灶有LGA参与供血,发生率为22.1%.23个有LGA参与供血的HCC病灶中,19个为巨块型,4个为结节型,22

  15. Identifying HIV-1 dual infections

    Directory of Open Access Journals (Sweden)

    Cornelissen Marion

    2007-09-01

    viral load during follow-up. The actual demonstration of dual infections involves a great deal of additional research to completely characterize the patient's viral quasispecies. The identification of a source partner would of course confirm the authenticity of the second infection.

  16. Evaluation of combined coronary CT angiography and dual-energy myocardial perfusion imaging for detection of acute myocardial infarction via second-generation dual-source CT:an experimental study in a porcine phantom model%第二代双源CT冠状动脉成像结合双能量心肌灌注评价猪急性心肌梗死的实验研究

    Institute of Scientific and Technical Information of China (English)

    孙凯; 李坤成; 韩瑞娟; 白栓成; 王君艳; 钱毅东; 刘智慧

    2015-01-01

    Objective To evaluate the diagnostic accuracy of dual-energy “one-step” combined CT coronary angiography ( CCTA ) and myocardial perfusion imaging ( MPI ) for the detection of acute myocardial infarction via second-generation dual-source CT compared with histopathological and conventional coronary angiography (CAG) findings in a porcine phantom. Methods Seven minipigs underwent transcatheter embolization of the coronary arteries by using gelatin sponge to produce acute myocardial infarction. CAG, dual-energy CCTA, and MPI were performed 20 min before, immediately after, and 24 h following the modeling procedure, respectively. A color-coded iodine map was used to evaluate the myocardial perfusion defects on the 17-segment model. In consensus, two radiologists interpreted all iodine map imaging results from MPI and CCTA. Considering CAG and pathological staining as gold standards, the sensibility and specificity of the CCTA and iodine maps from MPI were evaluated using dual-energy CT. Results Following coronary embolization, dual-energy CT iodine maps showed 45 infarcted segments and 40 non-infarcted segments. Per-segment analysis indicated the sensitivity, specificity, positive predictive value and negative predictive value as 93%, 95%, 95% and 93%, respectively. The corresponding values obtained by per-territory analysis were 100%, 86%, 89%and 100%, with CAG and histopathological findings as reference standards. The effective radiation dose of each dual-energy scan was 3.07±0.85 mSv(2.21-4.49 mSv). Conclusions Dual-energy “one-step” combined CCTA and MPI iodine maps for the detection of acute myocardial infarction via second-generation dual-source CT showed enhanced diagnostic accuracy with CAG and histopathology as gold standards.%目的:通过建立猪急性心肌梗死模型,以组织病理学和冠状动脉造影(CAG)结果为金标准,评价第二代双源CT双能量“一站式”冠状动脉CT血管造影(CCTA)结合心

  17. Application Value of Dual-source CT Low-dose Scanning in the Diagnosis of Adenoidal Hypertrophy in Children%双源CT低剂量扫描在诊断儿童腺样体肥大中的应用价值

    Institute of Scientific and Technical Information of China (English)

    王守玺

    2014-01-01

    Objective To evaluate and analyze the application value of dual-source CT low-dose scanning in the diagnosis of ade-noidal hypertrophy in children, so as to provide reliable reference for future clinical diagnostic work. Methods 76 cases of children clinically diagnosed as adenoidal hypertrophy admitted in our hospital from January, 2011 to December, 2013 were extracted. And they were divided into the control group and the observation group in accordance with the order of admission. The control group was given dual-source CT conventional-dose scanning, and the observation group was given dual-source CT low-dose scanning, the image quality, radiation dose and diagnostic results of both groups were compared and analyzed. Results There was no signifi-cant difference in the result of nasopharyngeal anatomy display between the observation group and the control group ( P>0.05), but the difference in adenoid CT value and radiation dose between the two groups was significant (P0.05),两组患儿腺样体CT值和辐射剂量比较存在差异有统计学意义(P<0.05)。结论经双源CT低剂量扫描可对儿童腺样体肥大做出准确的诊断,且其安全性较常规剂量扫描更高,临床诊断价值显著,值得关注并推广。

  18. Contribution of the intercalated adenosine at the helical junction to the stability of the gag-pro frameshifting pseudoknot from mouse mammary tumor virus.

    Science.gov (United States)

    Theimer, C A; Giedroc, D P

    2000-03-01

    The mouse mammary tumor virus (MMTV) gag-pro frameshifting pseudoknot is an H-type RNA pseudoknot that contains an unpaired adenosine (A14) at the junction of the two helical stems required for efficient frameshifting activity. The thermodynamics of folding of the MMTV vpk pseudoknot have been compared with a structurally homologous mutant RNA containing a G x U to G-C substitution at the helical junction (U13C RNA), and an A14 deletion mutation in that context (U13CdeltaA14 RNA). Dual wavelength optical melting and differential scanning calorimetry reveal that the unpaired adenosine contributes 0.7 (+/-0.2) kcal mol(-1) at low salt and 1.4 (+/-0.2) kcal mol(-1) to the stability (deltaG(0)37) at 1 M NaCl. This stability increment derives from a favorable enthalpy contribution to the stability deltadeltaH = 6.6 (+/-2.1) kcal mol(-1) with deltadeltaG(0)37 comparable to that predicted for the stacking of a dangling 3' unpaired adenosine on a G-C or G x U base pair. Group 1A monovalent ions, NH4+, Mg2+, and Co(NH3)6(3+) ions stabilize the A14 and deltaA14 pseudoknots to largely identical extents, revealing that the observed differences in stability in these molecules do not derive from a differential or specific accumulation of ions in the A14 versus deltaA14 pseudoknots. Knowledge of this free energy contribution may facilitate the prediction of RNA pseudoknot formation from primary nucleotide sequence (Gultyaev et al., 1999, RNA 5:609-617).

  19. Evidence for evoked release of adenosine and glutamate from cultured cerebellar granule cells

    Energy Technology Data Exchange (ETDEWEB)

    Schousboe, A.; Frandsen, A.; Drejer, J. (Univ. of Copenhagen (Denmark))

    1989-09-01

    Evoked release of ({sup 3}H)-D-aspartate which labels the neurotransmitter glutamate pool in cultured cerebellar granule cells was compared with evoked release of adenosine from similar cultures. It was found that both adenosine and (3H)-D-aspartate could be released from the neurons in a calcium dependent manner after depolarization of the cells with either 10-100 microM glutamate or 50 mM KCl. Cultures of cerebellar granule cells treated with 50 microM kainate to eliminate GABAergic neurons behaved in the same way. This together with the observation that cultured astrocytes did not exhibit a calcium dependent, potassium stimulated adenosine release strongly suggest that cerebellar granule cells release adenosine in a neurotransmitter-like fashion together with glutamate which is the classical neurotransmitter of these neurons. Studies of the metabolism of adenosine showed that in the granule cells adenosine is rapidly metabolized to ATP, ADP, and AMP, but in spite of this, adenosine was found to be released preferential to ATP.

  20. Role of adenosine signalling and metabolism in β-cell regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Olov, E-mail: olov.andersson@ki.se

    2014-02-01

    Glucose homeostasis, which is controlled by the endocrine cells of the pancreas, is disrupted in both type I and type II diabetes. Deficiency in the number of insulin-producing β cells – a primary cause of type I diabetes and a secondary contributor of type II diabetes – leads to hyperglycemia and hence an increase in the need for insulin. Although diabetes can be controlled with insulin injections, a curative approach is needed. A potential approach to curing diabetes involves regenerating the β-cell mass, e.g. by increasing β-cell proliferation, survival, neogenesis or transdifferentiation. The nucleoside adenosine and its cognate nucleotide ATP have long been known to affect insulin secretion, but have more recently been shown to increase β-cell proliferation during homeostatic control and regeneration of the β-cell mass. Adenosine is also known to have anti-inflammatory properties, and agonism of adenosine receptors can promote the survival of β-cells in an inflammatory microenvironment. In this review, both intracellular and extracellular mechanisms of adenosine and ATP are discussed in terms of their established and putative effects on β-cell regeneration. - Highlights: • A potential way to cure diabetes is to regenerate the β-cell mass by promoting cell survival, proliferation or neogenesis. • Adenosine may promote β-cell regeneration through several cellular mechanisms. • Adenosine and its cognate nucleotide ATP can each promote β-cell proliferation. • Do adenosine and ATP interact in promoting β-cell proliferation?.

  1. The A2B adenosine receptor impairs the maturation and immunogenicity of dendritic cells.

    Science.gov (United States)

    Wilson, Jeffrey M; Ross, William G; Agbai, Oma N; Frazier, Renea; Figler, Robert A; Rieger, Jayson; Linden, Joel; Ernst, Peter B

    2009-04-15

    The endogenous purine nucleoside adenosine is an important antiinflammatory mediator that contributes to the control of CD4(+) T cell responses. While adenosine clearly has direct effects on CD4(+) T cells, it remains to be determined whether actions on APC such as dendritic cells (DC) are also important. In this report we characterize DC maturation and function in BMDC stimulated with LPS in the presence or absence of the nonselective adenosine receptor agonist NECA (5'-N-ethylcarboxamidoadenosine). We found that NECA inhibited TNF-alpha and IL-12 in a concentration-dependent manner, whereas IL-10 production was increased. NECA-treated BMDC also expressed reduced levels of MHC class II and CD86 and were less effective at stimulating CD4(+) T cell proliferation and IL-2 production compared with BMDC exposed to vehicle control. Based on real-time RT-PCR, the A(2A) adenosine receptor (A(2A)AR) and A(2B)AR were the predominant adenosine receptors expressed in BMDC. Using adenosine receptor subtype selective antagonists and BMDC derived from A(2A)AR(-/-) and A(2B)AR(-/-)mice, it was shown that NECA modulates TNF-alpha, IL-12, IL-10, and CD86 responses predominantly via A(2B)AR. These data indicate that engagement of A(2B)AR modifies murine BMDC maturation and suggest that adenosine regulates CD4(+) T cell responses by selecting for DC with impaired immunogencity.

  2. Adenosine Monophosphate-Based Detection of Bacterial Spores

    Science.gov (United States)

    Kern, Roger G.; Chen, Fei; Venkateswaran, Kasthuri; Hattori, Nori; Suzuki, Shigeya

    2009-01-01

    A method of rapid detection of bacterial spores is based on the discovery that a heat shock consisting of exposure to a temperature of 100 C for 10 minutes causes the complete release of adenosine monophosphate (AMP) from the spores. This method could be an alternative to the method described in the immediately preceding article. Unlike that method and related prior methods, the present method does not involve germination and cultivation; this feature is an important advantage because in cases in which the spores are those of pathogens, delays involved in germination and cultivation could increase risks of infection. Also, in comparison with other prior methods that do not involve germination, the present method affords greater sensitivity. At present, the method is embodied in a laboratory procedure, though it would be desirable to implement the method by means of a miniaturized apparatus in order to make it convenient and economical enough to encourage widespread use.

  3. Late-onset adenosine deaminase deficiency presenting with Heck's disease.

    Science.gov (United States)

    Artac, Hasibe; Göktürk, Bahar; Bozdemir, Sefika Elmas; Toy, Hatice; van der Burg, Mirjam; Santisteban, Ines; Hershfield, Michael; Reisli, Ismail

    2010-08-01

    Focal epithelial hyperplasia, also known as Heck's disease, is a rare but distinctive entity of viral etiology with characteristic clinical and histopathological features. It is a benign, asymptomatic disease of the oral mucosa caused by human papilloma viruses (HPV). Previous studies postulated an association between these lesions and immunodeficiency. Genetic deficiency of adenosine deaminase (ADA) results in varying degrees of immunodeficiency, including neonatal onset severe combined immunodeficiency (ADA-SCID), and milder, later onset immunodeficiency. We report a 12-year-old girl with the late onset-ADA deficiency presenting with Heck's disease. Our case report should draw attention to the possibility of immunodeficiency in patients with HPV-induced focal epithelial hyperplasia.

  4. Adenosine-5'-phosphosulfate kinase is essential for Arabidopsis viability.

    Science.gov (United States)

    Mugford, Sarah G; Matthewman, Colette A; Hill, Lionel; Kopriva, Stanislav

    2010-01-04

    In Arabidopsis thaliana, adenosine-5'-phosphosulfate kinase (APK) provides activated sulfate for sulfation of secondary metabolites, including the glucosinolates. We have successfully isolated three of the four possible triple homozygous mutant combinations of this family. The APK1 isoform alone was sufficient to maintain WT levels of growth and development. Analysis of apk1 apk2 apk3 and apk1 apk3 apk4 mutants suggests that APK3 and APK4 are functionally redundant, despite being located in cytosol and plastids, respectively. We were, however, unable to isolate apk1 apk3 apk4 mutants, most probably because the apk1 apk3 apk4 triple mutant combination is pollen lethal. Therefore, we conclude that APS kinase is essential for plant reproduction and viability.

  5. Vasodilator effects of adenosine on retinal arterioles in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Nakazawa, Taisuke; Mori, Asami; Saito, Maki; Sakamoto, Kenji; Nakahara, Tsutomu; Ishii, Kunio

    2008-02-01

    Adenosine is a potent vasodilator of retinal blood vessels and is implicated to be a major regulator of retinal blood flow during metabolic stress, but little is known about the impact of diabetes on the role of adenosine in regulation of retinal hemodynamics. Therefore, we examined how diabetes affects adenosine-induced vasodilation of retinal arterioles. Male Wistar rats were treated with streptozotocin (80 mg/kg, intraperitoneally), and experiments were performed 6-8 weeks later. Rats were treated with tetrodotoxin (50 microg/kg, intravenously [i.v.]) to eliminate any nerve activity and prevent movement of the eye and infused with methoxamine continuously to maintain adequate systemic circulation. Fundus images were captured with a digital camera that was equipped with a special objective lens, and diameters of retinal arterioles were measured. Adenosine increased diameters of retinal arterioles and decreased systemic blood pressure. These responses were significantly attenuated by the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (30 mg/kg, i.v.) and the adenosine triphosphate-dependent K+ (K(ATP)) channel blocker glibenclamide (20 mg/kg, i.v.). The depressor responses to adenosine were reduced in diabetic rats, whereas diabetes did not alter vasodilation of retinal arterioles to adenosine. In contrast, both depressor response and vasodilation of retinal arteriole to acetylcholine were reduced in diabetic rats. The retinal vasodilator responses to adenosine and acetylcholine observed in diabetic rats were diminished by N(G)-nitro-L-arginine methyl ester. There were no differences in the responses to pinacidil, a K(ATP) channel opener, between the diabetic and nondiabetic rats. These results suggest that both the activation of nitric oxide synthase and opening of K(ATP) channels contribute to the vasodilator effects of adenosine in rats in vivo. However, diabetes has no significant impact on the vasodilation mediated by these mechanisms in

  6. Severe hemorrhage attenuates cardiopulmonary chemoreflex control of regional sympathetic outputs via NTS adenosine receptors.

    Science.gov (United States)

    Minic, Zeljka; Li, Cailian; O'Leary, Donal S; Scislo, Tadeusz J

    2014-09-15

    Selective stimulation of inhibitory A1 and facilitatory A2a adenosine receptor subtypes located in the nucleus of the solitary tract (NTS) powerfully inhibits cardiopulmonary chemoreflex (CCR) control of regional sympathetic outputs via different mechanisms: direct inhibition of glutamate release and facilitation of an inhibitory neurotransmitter release, respectively. However, it remains unknown whether adenosine naturally released into the NTS has similar inhibitory effects on the CCR as the exogenous agonists do. Our previous study showed that adenosine is released into the NTS during severe hemorrhage and contributes to reciprocal changes of renal (decreases) and adrenal (increases) sympathetic nerve activity observed in this setting. Both A1 and A2a adenosine receptors are involved. Therefore, we tested the hypothesis that, during severe hemorrhage, CCR control of the two sympathetic outputs is attenuated by adenosine naturally released into the NTS. We compared renal and adrenal sympathoinhibitory responses evoked by right atrial injections of 5HT3 receptor agonist phenylbiguanide (2-8 μg/kg) under control conditions, during hemorrhage, and during hemorrhage preceded by blockade of NTS adenosine receptors with bilateral microinjections of 8-(p-sulfophenyl) theophylline (1 nmol/100 nl) in urethane/chloralose anesthetized rats. CCR-mediated inhibition of renal and adrenal sympathetic activity was significantly attenuated during severe hemorrhage despite reciprocal changes in the baseline activity levels, and this attenuation was removed by bilateral blockade of adenosine receptors in the caudal NTS. This confirmed that adenosine endogenously released into the NTS has a similar modulatory effect on integration of cardiovascular reflexes as stimulation of NTS adenosine receptors with exogenous agonists.

  7. Value of Dual-source CT Angiography in the Diagnosis of Vertebral Artery Sulcus Ring%双源 CTA 在椎动脉沟环中的诊断价值

    Institute of Scientific and Technical Information of China (English)

    闫如意; 张朝利; 刘军华; 费军

    2014-01-01

    [Objective] To explore the value of dual-source CT angiography (DSCTA ) in the diagnosis of vertebral artery sulcus ring .[Methods]Clinical data of 62 patients with vertebral artery sulcus ring diagnosed by DSCTA were col-lected .The types of whole-ring-type vertebral artery sulcus ring were analyzed .The diameter of vertebral artery was measured .[Results] The types of 62 patients with vertebral artery included Ⅳ type in 38 patients(61 .3% ) in which 25 patients were bilateral whole-ring type and 13 patients were unilateral whole-ring type(8 patients with right side and 4 pa-tients with left side) ,Ⅲ type in 6 patients (9 .7% ) which were bone breaking in curve bone bridge arch with both beak-like sides ,typeⅠandⅡ in 18 patients(29 .0% ) in which 3 patients were type I anterior semi-ring and 15 patients were typeⅡ posterior semi-ring .The upper and lower diameters of whole-ring type vertebral artery sulcus ring were 3 .1~8 .2 (4 .8 ± 0 .3)mm and anteroposterior diameters were 4 .2~9 .1(7 .10 .3)mm .The diameter of vertebral artery in atlas ver-tebral artery sulcus ring was 1 .8~5 .9(3 .7 ± 0 .8)mm .Local stenosis of vertebral artery was found in 15 patients ,and the stenosis rate was 10% ~30% .[Conclusion]DSCTA can accurately display the shape of atlas vertebral artery sulcus ring and stenosis caused by vertebral artery entrapment .%【目的】探讨双源CT血管成像(CTA)在椎动脉沟环中的诊断价值。【方法】收集头颈部双源CTA检查中发现椎动脉沟环的患者62例的临床资料,分析椎动脉沟环分型并测量椎动脉直径。【结果】62例椎动脉沟环的分型:Ⅳ型38例,占61.3%,其中25例为双侧全环型,13例为单侧全环型(右侧8例、左侧4例);Ⅲ型6例,占9.7%,为弧形骨桥弓顶部骨质中断,两端呈鸟嘴状;Ⅰ型及Ⅱ型18例,占29.0%,其中Ⅰ型(前半环)3例、Ⅱ型(后半环)15例。测量全环型椎动脉沟环上下径3.1

  8. 双源CT冠状动脉造影在心律失常患者的临床应用%Clinical Application of Dual-source CT Coronary Angiography in Patients with Arrhythmia

    Institute of Scientific and Technical Information of China (English)

    胡春峰; 徐凯; 袁莹莹; 汪秀玲; 李绍东; 程广军; 谢丽响

    2012-01-01

    Purpose: To study the clinical application value of dual-source CT coronary angiography (DSCT-CA) in patients with arrhythmia. Methods: Seventy-three patients with arrhythmia (29 patients with ventricular extrasystoles, 25 with atrial extrasystoles, 19 with atrial fibrillation) underwent DSCT-CA in this study. Retrospective gating technique and ECG editing technique were used. Coronary segment image quality was evaluated by four-grade method. Average heart rate and heart rate variability between ECG-editing group and no ECG- editing group and the image quality of pre-editing and post-editing in ECG-editing group were compared respectively. Results: In 73 patients, ECG-editing was not needed in 14 patients, and ECG-editing was needed in 59 patients. The average heart rate and heart rate variability between ECG-editing group and no ECG-editing group was with significant difference (P< 0.05 ). The image quality in every segment of ECG-editing group between pre-editing and post-editing was also with significant difference ( P < 0.05 ). After ECG-editing, 11 segments did not reach diagnosis requirements. Conclusion: DSCT-CA can be used in patients with arrhythmia. The image quality of coronary artery could be significantly improved with ECG-editing in patients with arrhythmia, but the key to improve the quality of image is to control heart rate and heart rate variability.%目的:探讨双源CT冠状动脉造影(DSCT-CA)在心律失常患者中的临床应用价值.方法:行DSCT-CA的心律失常患者共73例(室性期前收缩29例,房性期前收缩25例,心房纤颤19例),采用回顾性心电门控重建图像及心电编辑技术,对各段血管图像质量分级,比较无需编辑组与需编辑组的平均心率及心率波动、需编辑组各段冠状动脉编辑前后的图像质量.结果:73例中14例为无需编辑组,59例为需编辑组.无需编辑组的平均心率、心率波动均明显低于需编辑组(P<0.05).心电编辑后各段冠状动脉

  9. Applied anatomy of myocardial bridge-mural coronary artery by dual-source CT%心肌桥-壁冠状动脉临床应用解剖的双源CT研究

    Institute of Scientific and Technical Information of China (English)

    虞康惠; 成官迅; 刘国顺; 阎静

    2012-01-01

    Objective To study the morphologic features of myocardial bridge-mural coronary (MB-MCA) by dual-source CT (DSCT), and improve the understanding of it on clinical diagnosis value. Methods 3709 patients were involved in this study. MB-MCAs were located accurately according to the guideline of the American Heart Association, and the length, depth, compression of MB-MCA and concomitant atheromatous changes were evaluated. Results 638 cases had MB-MCA in overall 3709 patients by DSCT, getting the prevalence of 17.20%. 654 MB-MCA were detected including 426 in segment 7, 72 in segment 8 and 56 in segment 6, the rest distributing in segment 2, 3, 4, 9, 11, 12,13 and 16. Of 654 MB-MCA, the mean length was (20.52± 9.84 )mm and the mean thickness was (1.27± 0.93 )mm. The lumen of MCA showed no significant stenosis or mild to moderate stenosis, and a rare severe stenosis. 92 patients with MB-MCA had atherosclerotic plaque. Conclusions DSCT not only may directly demonstrate the dissection shape of MB-MCA, but might also dynamically evaluate the change of MB-MCA in the entire cardiac cycle, supplying the clinical significance research of MB-MCA for valuable information.%目的 研究心肌桥-壁冠状动脉(MB-MCA)的双源CT(DSCT)形态学特征,以提高对MB-MCA临床诊断价值的认识.方法 分析3709例冠状动脉CTA病人,根据美国心脏病协会的冠状动脉16段分段法对检出的MB-MCA进行准确定位,对其长度、深度、收缩期管腔压缩程度及其伴随的粥样硬化情况进行评估.结果 3709例病人中发现MB-MCA 638例,检出率约17.20%,共检出654支MB-MCA,其中426支位于7段(S7)、72支位于8段(S8)、56支位于6段(S6),其余分别分布于2段(S2)、3段(S3)、4段(S4)、9段(S9)、11段(S11)、12段(S12)、13段(S13)及16段(S16);MB-MCA平均长度为( 20.52±9.84 )mm,平均深度为(1.27±0.93 )mm;收缩期时MCA管腔呈现不同程度的狭窄,但重度狭窄罕见;92例MB-MCA患者

  10. "How to" incorporate dual-energy imaging into a high volume abdominal imaging practice.

    Science.gov (United States)

    Tamm, Eric P; Le, Ott; Liu, Xinming; Layman, Rick R; Cody, Dianna D; Bhosale, Priya R

    2017-03-01

    Dual-energy CT imaging has many potential uses in abdominal imaging. It also has unique requirements for protocol creation depending on the dual-energy scanning technique that is being utilized. It also generates several new types of images which can increase the complexity of image creation and image interpretation. The purpose of this article is to review, for rapid switching and dual-source dual-energy platforms, methods for creating dual-energy protocols, different approaches for efficiently creating dual-energy images, and an approach to navigating and using dual-energy images at the reading station all using the example of a pancreatic multiphasic protocol. It will also review the three most commonly used types of dual-energy images: "workhorse" 120kVp surrogate images (including blended polychromatic and 70 keV monochromatic), high contrast images (e.g., low energy monochromatic and iodine material decomposition images), and virtual unenhanced images. Recent developments, such as the ability to create automatically on the scanner the most common dual-energy images types, namely new "Mono+" images for the DSDECT (dual-source dual-energy CT) platform will also be addressed. Finally, an approach to image interpretation using automated "hanging protocols" will also be covered. Successful dual-energy implementation in a high volume practice requires careful attention to each of these steps of scanning, image creation, and image interpretation.

  11. Single-source dual-energy CT angiography with reduced iodine load in patients referred for aortoiliofemoral evaluation before transcatheter aortic valve implantation: impact on image quality and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Dubourg, Benjamin; Caudron, Jerome; Lefebvre, Valentin; Dacher, Jean-Nicolas [Rouen University Hospital, Department of Radiology, Rouen (France); UFR Medecine Pharmacie, INSERM U1096, Rouen (France); Lestrat, Jean-Pierre [Rouen University Hospital, Department of Radiology, Rouen (France); Bubenheim, Michael [Rouen University Hospital, Department of Biostatistics, Rouen (France); Godin, Matthieu; Tron, Christophe [Rouen University Hospital, Department of Cardiology, Rouen (France); Eltchaninoff, Helene; Bauer, Fabrice [Rouen University Hospital, Department of Cardiology, Rouen (France); UFR Medecine Pharmacie, INSERM U1096, Rouen (France)

    2014-11-15

    To compare image quality and radiation dose of pre-transcatheter aortic valve implantation (TAVI) aortoiliofemoral CT angiography (AICTA) provided by standard vs. dual-energy mode with reduced iodine load protocols. One hundred and sixty-one patients underwent a two-step CTA protocol before TAVI including cardiac CTA with injection of 65 mL of iodinated contrast agent (ICA), immediately followed by AICTA. From this second acquisition, the following three different patient groups were identified: Group 1: 52 patients with standard AICTA (60 mL ICA, 100 kVp, mA automodulation); Group 2: 48 patients with dual-energy AICTA with 50 % iodine load reduction (30 mL ICA, fast kVp switching, 600 mA); Group 3: 61 patients with an identical protocol to Group 2, but exposed to 375 mA. The qualitative/subjective image quality (13-point score) and quantitative/objective image quality (contrast attenuation and image noise) were evaluated. The radiation dose was recorded. There was no significant difference in non-diagnostic images between the three protocols. Contrast attenuation, signal-to-noise ratio and contrast-to-noise ratio were significantly higher, whereas noise was significantly lower in the standard protocol (all P < 0.05). The radiation dose was lower in the dual-energy protocol at 375 mA (P < 0.05). Dual-energy AICTA before TAVI results in a reduction of iodine load while maintaining sufficient diagnostic information despite increased noise. (orig.)

  12. The adenosine A2B receptor is involved in anion secretion in human pancreatic duct Capan-1 epithelial cells

    DEFF Research Database (Denmark)

    Hayashi, M.; Inagaki, A.; Novak, Ivana;

    2016-01-01

    Adenosine modulates a wide variety of biological processes via adenosine receptors. In the exocrine pancreas, adenosine regulates transepithelial anion secretion in duct cells and is considered to play a role in acini-to-duct signaling. To identify the functional adenosine receptors and Cl− chann...

  13. Role of adenosine A2b receptor overexpression in tumor progression.

    Science.gov (United States)

    Sepúlveda, Cesar; Palomo, Iván; Fuentes, Eduardo

    2016-12-01

    The adenosine A2b receptor is a G-protein coupled receptor. Its activation occurs with high extracellular adenosine concentration, for example in inflammation or hypoxia. These conditions are generated in the tumor environment. Studies show that A2b receptor is overexpressed in various tumor lines and biopsies from patients with different cancers. This suggests that A2b receptor can be used by tumor cells to promote progression. Thus A2b participates in different events, such as angiogenesis and metastasis, besides exerting immunomodulatory effects that protect tumor cells. Therefore, adenosine A2b receptor appears as an interesting therapeutic target for cancer treatment.

  14. Adenine arabinoside inhibition of adenovirus replication enhanced by an adenosine deaminase inhibitor.

    Science.gov (United States)

    Wigand, R

    1979-01-01

    The inhibition of adenovirus multiplication by adenine arabinoside was determined by yield reduction in one-step multiplication cycle. Inhibition was greatly enhanced by an adenosine deaminase inhibitor (2-deoxycoformycin) in concentrations down to 10 ng/ml. Adenovirus types from four subgroups showed similar results. However, the enhancing effect of adenosine deaminase inhibitor was great in HeLa cells, moderate in human fibroblasts, and negligible in Vero cells. This difference could be explained by different concentrations of adenosine deaminase found in cell homogenates.

  15. An STS in the human adenosine deaminase gene (located 20q12-q13. 11)

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, B.C.; States, J.C. (Wayne State Univ., Detroit, MI (United States))

    1991-09-25

    The human adenosine deaminase gene has been characterized in detail. The adenosine gene product, as part of the purine catabolic pathway, catalyzes the irreversible deamination of adenosine and deoxyadenosine. Deficiency of this activity in humans is associated with an autosomal recessive form of severe combined immunodeficiency disease. Recently, this genetic deficiency disease has been targeted for the first attempts at gene therapy in humans. Using the polymerase chain reaction (PCR), a fragment of the expected size (160 bp) was amplified from human genomic DNA.

  16. Adenosine A2A receptor binding profile of two antagonists, ST1535 and KW6002: consideration on the presence of atypical adenosine A2A binding sites

    Directory of Open Access Journals (Sweden)

    Teresa Riccioni

    2010-08-01

    Full Text Available Adenosine A2A receptors seem to exist in typical (more in striatum and atypical (more in hippocampus and cortex subtypes. In the present study, we investigated the affinity of two adenosine A2A receptor antagonists, ST1535 [2 butyl -9-methyl-8-(2H-1,2,3-triazol 2-yl-9H-purin-6-xylamine] and KW6002 [(E-1,3-diethyl-8-(3,4-dimethoxystyryl-7-methyl-3,7-dihydro-1H-purine-2,6,dione] to the “typical” and “atypical” A2A