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Equivalent Area (equivalent + area)

Distribution by Scientific Domains
Life Sciences40%

Selected Abstracts

New expression for the resonance frequency of an E-shaped microstrip patch antenna

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2006
Dipak K. Neog
Abstract The resonance frequency of an E-shaped microstrip antenna has been calculated by equating its area to an equivalent area of a rectangular microstrip patch antenna. A new expression for effective dielectric constant is developed for the E-shaped microstrip patch antenna. The new expression of resonance frequency is used to calculate the results, which are in good agreement with the measured and published results. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1561,1563, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21700 [source]

Activation of immature microglia in response to stab wound in embryonic quail retina

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2005
Ana M. Sánchez-López
Abstract Activation of mature (ramified) microglia in response to injury in the adult central nervous system (CNS) is well documented. However, the response of immature (ameboid) microglia to injury in the developing CNS has received little attention. In this study, a stab wound was made in embryonic quail retinas at incubation days 7 and 9, and the response of retinal microglial cells was analyzed at different times between days 1 and 37 postinjury. The appearance of microglial cells within the wound occurred at the same time as the arrival of the first migrating ameboid microglial cells at an equivalent area in control retinas. Therefore, no specific attraction of microglia toward the wound was observed. Microglial cells in the wound had phenotypic features similar to those of activated microglia in the adult CNS. Thus, their shape was more compact compared with microglial cells outside the wound, expression of the molecule recognized by the QH1 antibody was up-regulated, and their lysosomal compartment was markedly increased. Transitional forms between normal ameboid and activated-like microglial cells were seen at the wound edge, supporting the view that ameboid microglia become activated when they contact the wound during the normal course of their migration in the retina. The microglial reaction was maintained within the wound at 37 days postinjury. In addition to the stab wound, secondary damage areas were found in experimental retinas. Activated cells could still be observed in these areas at 37 days postinjury. J. Comp. Neurol. 492:20,33, 2005. © 2005 Wiley-Liss, Inc. [source]

Photoelectron Generation by Photosystem,II Core Complexes Tethered to Gold Surfaces

CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 4 2010
Michele Vittadello, Prof.
Abstract By using a nondestructive, ultrasensitive, fluorescence kinetic technique, we measure in,situ the photochemical energy conversion efficiency and electron transfer kinetics on the acceptor side of histidine-tagged photosystem,II core complexes tethered to gold surfaces. Atomic force microscopy images coupled with Rutherford backscattering spectroscopy measurements further allow us to assess the quality, number of layers, and surface density of the reaction center films. Based on these measurements, we calculate that the theoretical photoelectronic current density available for an ideal monolayer of core complexes is 43,,A,cm,2 at a photon flux density of 2000,,mol,quanta,m,2,s,1 between 365 and 750,nm. While this current density is approximately two orders of magnitude lower than the best organic photovoltaic cells (for an equivalent area), it provides an indication for future improvement strategies. The efficiency could be improved by increasing the optical cross section, by tuning the electron transfer physics between the core complexes and the metal surface, and by developing a multilayer structure, thereby making biomimetic photoelectron devices for hydrogen generation and chemical sensing more viable. [source]

Track analysis and conservation priorities in the cloud forests of Hidalgo, Mexico

DIVERSITY AND DISTRIBUTIONS, Issue 3 2000
Isolda Luna Vega
Abstract .,A track analysis based on the distributional patterns of 967 species of vascular plant taxa (gymnosperms, angiosperms and pteridophytes) was performed to assess conservation priorities for cloud forests in the state of Hidalgo, Mexico, ranged in the municipalities of Chapulhuacán, Eloxochitlán, Molocotlán, Pisaflores, Tenango de Doria, Tlahuelompa and Tlanchinol, as well as five floristically equivalent areas in the states of Veracruz (Teocelo and Helechales), Tamaulipas (Gómez Farías), Morelos-México (Ocuilan) and Oaxaca (Huautla de Jiménez). In order to detect generalized tracks we employed a new parsimony method, where clades (considered equivalent to generalized tracks) are defined forbidding homoplasy and acting like a compatibility algorithm. Several generalized tracks were found connecting these areas. Cloud forests of Chapulhuacán were connected according to three different generalized tracks and thus have a higher value, qualifying as a priority area for the conservation of cloud forests in the state of Hidalgo. [source]

Management of drug-to-drug interactions between cyclosporine A and the protease-inhibitor lopinavir/ritonavir in liver-transplanted HIV-infected patients

LIVER TRANSPLANTATION, Issue 7 2004
Martin Vogel
Highly active antiretroviral therapy (HAART) has improved the life expectancy of HIV-infected patients, allowing orthotopic liver transplantation as a reasonable treatment option for selected patients with terminal liver disease. Both non-nucleoside reverse transcriptase inhibitors and protease inhibitors, key elements of HAART, give rise to substantial drug-to-drug interactions with immunosuppressive drugs such as tacrolimus and cyclosporine A. After studying 12-hour pharmacokinetic profiles in 3 HIV-positive patients after liver transplantation, we describe how dosing of cyclosporine A can be adjusted to maintain effective immunosuppressive drug levels on a daily dosing schedule when ritonavir-boosted indinavir or lopinavir-based antiretroviral therapy is given. To avoid toxic drug levels, we used an orally available cyclosporine A formulation prepared from the commercial available intravenous solution, which enabled dose adjustments in 1-mg increments. Under ritonavir-boosted HAART, cyclosporine A levels showed markedly altered absorption/elimination characteristics with more or less constant blood-levels throughout the dosing interval and prolonged elimination half-lives up to 38 hours. To obtain equivalent areas under the curve of cyclosporine A, daily doses were reduced to 5,20% of the individual standard doses given before initiation of ritonavir-boosted HAART. Because of the flat absorption/elimination profiles under ritonavir-boosted HAART cyclosporine A, dosing could be reliably monitored long term by measuring cyclosporine A trough-levels. (Liver Transpl 2004;10:939,944.) [source]