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11.
Qayyum AA Vejlstrup NG Ahtarovski KA Kofoed KF Kastrup J 《Magnetic resonance imaging》2012,30(6):889-892
Since the introduction of percutaneous coronary intervention for coronary artery disease, thousands of patients have been treated with the implantation of coronary stents. Moreover, several of the patients with coronary stent undergo cardiac magnetic resonance (CMR) imaging every year. This case report is of a 77-year-old man who was previously treated with the implantation of a coronary stent in the left circumflex artery. He underwent CMR imaging, which revealed a process 14×21 mm in the left atrium. Cardiac contrast computed tomography did not demonstrate any cardiac pathology. While the signal loss on MRI associated with implanted metallic devices is known, we report a case where an implanted coronary stent in the left circumflex artery led to an intracardiac signal loss mimicking intracardiac thrombus/tumor. 相似文献
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Alharbi F. F. Aman Salma Ahmad Naseeb Ejaz Syeda Rabia Khosa Rabia Yasmin Abid Abdul Ghafoor Manzoor Sumaira Al-Buriahi M. S. Alrowaili Z. A. Farid Hafiz Muhammad Tahir 《Journal of Solid State Electrochemistry》2022,26(5):1251-1258
Journal of Solid State Electrochemistry - Scientists are increasingly interested in improving electroactive technologies for supercapacitor applications, since energy storage devices have improved... 相似文献
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A. Qayyum B. Ahmad M.N. Akhtar S. Ahmad 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,3(3):267-274
A study has been conducted into the mechanisms of evolution of clusters and their subsequent fragmentation under energetic
heavy ion bombardment of amorphous graphite. The evolving clusters and their subsequent fragmentation under continuing ion
bombardment are revealed by detecting various clusters in the energy spectra of the Direct Recoils (DRs) emitted as a result
of collisions between ions and surface constituents. The successive DR spectra reveal that the energetics of bond formation as well as any subsequent fragmentation can be related to the processes of energy dissipation in a cylindrical
volume of a few ? surrounding the ion path. The dependence of formation or fragmentation is seen to be a function of the ionic stopping powers in this cylindrical volume.
Received: 2 January 1998 / Accepted: 5 March 1998 相似文献
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The isothermal crystallization of isotactic polypropylene at different temperatures in the presence of fibrous substrates has been investigated. It is shown that preferential transcrystalline growth occurs at the fiber surface and that changes in nucleation density in the bulk material adjacent to the fibers also occur, the extent of which is dependent on temperature and fiber volume fraction. The effects are discussed in terms of the diffusion of heterogeneities in the bulk due to interaction and the adsorption on the fibers. 相似文献
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A model is proposed to explain the generation of current oscillations in CdS samples due to impurity breakdown. Some of the rules obeyed by such breakdown and current oscillations accompanying it were investigated. 相似文献
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M. Ijaz Khan Tasawar Hayat Sumaira Qayyum Muhammad Imran Khan A. Alsaedi 《Physics letters. A》2018,382(34):2343-2353
Here a novel applications of entropy generation optimization is presented for nonlinear Sisko nanomaterial flow by rotating stretchable disk. Flow is examined in the absence of magnetohydrodynamics and Joule heating. Total irreversibility rate (entropy generation rate) is investigated for different flow parameters. Heat source/sink and viscous dissipation effects are considered. Impacts of Brownian motion and thermophoresis on irreversibility have been analyzed. Governing flow equations comprise momentum, energy and nanoparticle concentration. Von Karman's similarity variables are implemented for reduction of PDEs into ODEs. Homotopy analysis technique for series solutions is implemented. Attention is given to the irreversibility. The impacts of different flow parameters on velocity, nanoparticle concentration, temperature and irreversibility rate are graphically presented. From obtained results it is examined that irreversibility rate enhances for larger estimation of Brinkman number and diffusion. Furthermore it is also examined that temperature and nanoparticle concentration show contrast behavior through Prandtl number and Brownian motion. 相似文献
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A. Qayyum Shaista Zeb N.U. Rehman M. Zakaullah 《Journal of Quantitative Spectroscopy & Radiative Transfer》2007,107(3):361-371
Optical emission spectroscopy measurements are presented to characterize the different excitation and ionization processes of both atomic and molecular species in Ar-N2 mixture plasma under different discharge conditions. Particularly, the emission intensities of nitrogen (0-0) band of second positive system at 337.1 nm and (0-0) band of first negative systems at 391.4 nm are used to determine the dependence of their radiative states on argon fraction in the mixture. It is observed that the addition of argon gas influences the radiative states differently due to their different populating mechanisms. The results demonstrate that the addition of argon to nitrogen plasma remarkably enhance the population of N2(C3Πu) radiative state through Penning excitation involving argon metastable states. The electron temperature is determined from Ar-I spectral line intensities, using Boltzmann's plot method and is found to depend on argon fraction in the mixture. 相似文献
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A new compound, jolynamine (1), was isolated from the marine brown alga Jolyna laminarioides collected from the coast of Karachi, Pakistan. In addition, four known compounds, namely saringosterol (2), loliolide (3), methyl-4-hydroxybenzoate (4) and propyl-4-hydroxybenzoate (5), were isolated for the first time from the marine brown alga Iyengaria stellata, and two known compounds, namely 3,4,5-trimethylaniline (6) and harmine (7), were isolated for the first time from the marine brown alga Melanothamnus afaqhusainii. Compound 6 is synthetically known but was isolated for the first time from a natural source. The structures of these compounds were elucidated with the help of powerful spectroscopic techniques. Furthermore, the methanolic extracts of both algae showed anti-microbial activities against various bacteria and fungi. 相似文献