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Air Cavities (air + cavity)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

White-marker imaging,Separating magnetic susceptibility effects from partial volume effects

MAGNETIC RESONANCE IN MEDICINE, Issue 3 2007
Jan-Henry Seppenwoolde
Abstract By applying dephasing gradients, local magnetic field inhomogeneitiescan selectively visualized with positive contrast, such as those created by magnetically labeled cells. This is known as "white-marker imaging." In white-marker imaging, subvoxel signal variations are also visualized as a result of partial volume (PV) effects and may compromise the identification of magnetic structures (e.g., magnetically-labeled cells). This study presents the theory and proof-of-principle experiments of a strategy to eliminate PV effects during white-marker imaging. The strategy employs the asymmetry of the signal response curves for non-PV effects as a function of externally applied gradients. In the case of PV effects, subtraction of the symmetrical signal responses eliminates their contribution. In vitro experimental images were made using a spherical phantom with cylindrical elements. In vivo images of the brain were obtained at a location that included air cavities (susceptibility effects) and the circle of Willis (PV effect). The results show that PV effects were eliminated in the in vitro experiments and were virtually absent under in vivo conditions. Magn Reson Med, 2007. © 2007 Wiley-Liss, Inc. [source]

LTCC stripline resonator using embedded air cavities for millimeter wave applications

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2008
Young Chul Lee
Abstract A stripline T-resonator is designed and implemented in the LTCC substrate for millimeter wave applications. The loss-free air cavities are embedded at both side edges of the conducting strip in order to efficiently reduce the dielectric loss of the stripline structure. The resonator was implemented using 4-layer LTCC dielectrics. The fabricated stripline resonator with air cavities reveals Q-factor of 248 and total loss of 0.035 dB/mm at 34.7 GHz, and that is improved by 108% and 51%, respectively, compared to the conventional one. The proposed LTCC stripline resonator with the embedded air cavities can meet demands for low-loss millimeter-wave system-on-package (SoP) applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 658,661, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23151 [source]

Agar sublimation test for the in vitro determination of the antifungal activity of morpholine derivatives

MYCOSES, Issue 5-6 2004
A. Polak
Antimykotische Aktivität; Morpholine; Sublimation Summary We studied the in vitro antifungal activities of a wide range of antimycotic agents, including amorolfine, terbinafine, naftifine, five morpholine derivatives, ciclopiroxolamine, bifonazole, clotrimazole, ketoconazole, itraconazole, fluconazole, voriconazole, flucytosine, amphotericin B, nystatin, and caspofungin, against Candida albicans and Trichophyton rubrum by conventional agar diffusion tests and by a novel sublimation method. For the sublimation method, 6 mm filter paper disks were soaked with defined amounts of antimycotic drugs, air dried, placed in the center of the lids of 9 cm Petri dishes, and incubated upside down with inoculated agar plates 10 mm above the disks. The conventional disk diffusion tests produced inhibition zones as previously described. The disk sublimation tests produced large inhibition zones with amorolfine, five amorolfine derivatives, and terbinafine, but with none of the other antifungal agents. Possible therapeutic advantages of agents, which are able to overcome air cavities in mycotic lesions, e.g. in onychomycosis, are discussed. Zusammenfassung Wir untersuchten in vitro die antimykotische Aktivität eines breiten Spektrums von Antimykotika, einschließlich Amorolfin, Terbinafin, Naftifin, fünf Morpholin-Derivaten, Ciclopiroxolamin, Bifonazol, Clotrimazol, Ketoconazol, Itraconazol, Fluconazol, Voriconazol, 5-Fluorcytosin, Amphotericin B, Nystatin und Caspofungin, gegenüber Candida albicans und Trichophyton rubrum mit konventionellen Agardiffusionstesten und mit einer neuartigen Sublimationsmethode. Für die Sublimationsmethode wurden 6 mm-Filterpapier-Blättchen mit definierten Mengen von Antimykotika getränkt, luftgetrocknet, in die Mitte der Deckel von 9 cm-Petrischalen gelegt und mit der inokulierten Agarplatte 10 mm über den Blättchen umgedreht inkubiert. Die konventionellen Agardiffusionsteste produzierten Hemmhöfe wie früher beschrieben. Die Blättchen-Sublimationsteste produzierten große Hemmhöfe mit Amorolfin, fünf Morpholin-Derivaten und Terbinafin, nicht jedoch mit den anderen Antimykotika. Mögliche therapeutische Vorteile von Agentien, die luftgefüllte Hohlräume in mykotischen Läsionen überbrücken können, z. B. im Nagel bei Onychomykose, werden diskutiert. [source]