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Specific Flow (specific + flow)
Selected AbstractsSeasonal fluctuations of selenium and sulfur accumulation in selenium hyperaccumulators and related nonaccumulatorsNEW PHYTOLOGIST, Issue 3 2007Miriam L. Galeas Summary ,,Some plants hyperaccumulate selenium (Se) up to 1% of dry weight. This study was performed to obtain insight into whole-plant Se fluxes in hyperaccumulators. ,,Selenium hyperaccumulators Astragalus bisulcatus and Stanleya pinnata were monitored over two growing seasons for seasonal fluctuations in concentrations of Se and the chemically similar element sulfur (S). The related nonhyperaccumulators Astragalus sericoleucus, Oxytropis sericea and Thlaspi montanum were included for comparison. ,,In both hyperaccumulators leaf Se decreased from April to October, coinciding with Se hyperaccumulation in flowers and seeds. Root Se levels were lowest in summer. Selenium concentration decreased with leaf age in both hyperaccumulators. Leaf S levels peaked in summer in all plant species, as did Se levels in nonhyperaccumulators. Selenium and S levels tended to be negatively correlated in hyperaccumulators, and positively correlated in nonhyperaccumulators. ,,These results suggest a specific flow of Se in hyperaccumulator plants over the growing season, from root to young leaves in spring, followed by remobilization from aging leaves to reproductive tissues in summer, and back to roots in the autumn. [source] Elucidation of the gating of the GIRK channel using a spectroscopic approachTHE JOURNAL OF PHYSIOLOGY, Issue 22 2009Adi Raveh The traditional view of G protein-coupled receptor (GPCR)-mediated signalling puts the players in this signalling cascade, namely the GPCR, the G protein and its effector, as individual components in space, where the signalling specificity is obtained mainly by the interaction of the GPCR and the G, subunits of the G protein. A question is then raised as to how fidelity in receptor signalling is achieved, given that many systems use the same components of the G protein signalling machinery. One possible mechanism for obtaining the specific flow of the downstream signals, from the activated G protein to its specific effector target, in a timely manner, is compartmentalization, a spatial arrangement of the complex in a rather restricted space. Here we review our recent findings related to these issues, using the G protein-coupled potassium channel (GIRK) as a model effector and fluorescence-based approaches to reveal how the signalling complex is arranged and how the G protein exerts its action to activate the GIRK channel in intact cells. [source] Can color doppler predict the uniformity of HIFU-induced prostate tissue destruction?THE PROSTATE, Issue 4 2004Olivier Rouvière Abstract Background Tissue blood perfusion influences the results of some hyperthermia and thermotherapy procedures, but its role in the outcome of prostate cancer treatment by high-intensity focused ultrasound (HIFU) has not been evaluated yet. We evaluated preoperative prostate color Doppler as a predictor of the efficacy of HIFU treatment. Methods Thirty-five patients underwent pre- and post-contrast color Doppler examination of the prostate before HIFU treatment. Specific software was used to calculate, on color Doppler images, the color pixel density (CPD), and the specific flow (SF, i.e., mean velocity,×,CPD) in different regions of interest. Post-treatment sextant biopsies were obtained in 31 patients, 5.8,±,2.8 months after HIFU treatment. Results No significant correlation was found between the uniformity of HIFU-induced tissue destruction observed on control biopsies and the pre-treatment CPD/SF values in any region of interest, either before or after contrast injection. On the other hand, history of radiation therapy was significantly associated with homogeneous tissue destruction and history of hormone therapy was significantly associated with incomplete tissue destruction. Conclusions Color Doppler cannot predict the uniformity of HIFU-induced tissue destruction. History of radiation therapy was found to be a factor of favorable prognosis and history of hormone therapy was found to be a factor of poor prognosis in our population. © 2004 Wiley-Liss, Inc. [source] A tale of networks and policies: prolegomena to an analysis of irregular migration careers and their developmental pathsPOPULATION, SPACE AND PLACE (PREVIOUSLY:-INT JOURNAL OF POPULATION GEOGRAPHY), Issue 3 2010Martina Cvajner Abstract In recent decades, large-scale irregular migration flows and systems have developed across Europe. Although such systems involve most European countries and are often treated as being similar, their structures and dynamics are quite different. Some irregular migration systems have developed through clandestine entries, while other systems are almost entirely the result of overstaying. Some systems have been structured around a sequence of self-contained spells of irregular work, while others have involved long-term irregular residence. Some have coupled specific flows with specific niches in the occupational structures, while others have shown no significant connections with specific sectors of employment. This paper is based on what has been learned from an immigrant life-history project carried out in Italy in recent years, and describes three different types of irregular migratory systems that are themselves rooted in three different kinds of migration careers: atomistic, volume-based and structured. The paper argues that the distinction between different irregular migration systems is crucial both for structural and developmental analysis. Differences in the structure of irregular migration systems should also be taken into account in the analyses of the impact of different migration control policies. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||