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Functional Point (functional + point)
Selected AbstractsPerformance issues of bandwidth management in ATM networksINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 2 2003Christos Bouras Abstract In our days, efficient management of the available network resources becomes a critical issue, both from a functional point of view (so that users can be provided with the bandwidth they need), and an economical point of view (so that carriers can satisfactorily and efficiently serve as many customers as possible and at the same time increase their revenue). In this paper we consider a bandwidth control scheme (i.e. managed bandwidth service) for an ATM network infrastructure which is applied to the Greek research and technology network (GRNET). We present some methods that we have tested (in a simulation setting) in order to increase the efficiency of the system and the utilization of the available bandwidth. More specifically, we consider a bandwidth-resizing algorithm for virtual paths, in order to keep the allocated bandwidth very close to the bandwidth actually used. This leads to an increased number of accepted requests and better network utilization. We, also, use the simulation results in order to get an estimation of the effective bandwidth for VBR paths that can be used in call admission. Finally, we consider a semi-offline scheme where requests are gathered and considered for acceptance in regular intervals. Simulation results show an increase in the utilization of resources. As a further improvement, we allow connections to be allocated a little before or after the time initially requested. This leads to further improvement in network utilization. All the improvement schemes were tested with the ATM-TN simulator and the results look promising. Copyright © 2003 John Wiley & Sons, Ltd. [source] Sunflower proteins: overview of their physicochemical, structural and functional propertiesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2007Sergio González-Pérez Abstract There is increasing worldwide demand for proteins of both animal and plant origin. However, animal proteins are expensive in terms of both market price and environmental impact. Among alternative plant proteins, sunflower seeds are particularly interesting in view of their widespread availability in areas where soy is not or only sparsely produced. Compared with other sources of vegetable proteins, sunflower seeds have been reported to have a low content of antinutritional factors. Although the absence of these factors is important, the functionality of the protein preparations will mainly determine their applicability. This review provides detailed information about sunflower seed composition and processing, including processes to remove phenolic compounds from meals. The main part of the review concerns the structure and functionality of the two major protein fractions, helianthinin and 2S albumins. Regarding functionality, emphasis is on solubility, thermal behaviour and surface activity. Protein structure and functionality are discussed as a function of extrinsic factors such as pH, ionic strength, temperature and the presence of other seed components, particularly chlorogenic acid. In addition, sunflower proteins are compared from a structural and functional point of view with other plant proteins, particularly soy proteins. Copyright © 2007 Society of Chemical Industry [source] Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells.MICROSCOPY RESEARCH AND TECHNIQUE, Issue 4 2010Part 2: Changes in spermatid organelles associated with development of spermatozoa Abstract Spermiogenesis is a long process whereby haploid spermatids derived from the meiotic divisions of spermatocytes undergo metamorphosis into spermatozoa. It is subdivided into distinct steps with 19 being identified in rats, 16 in mouse and 8 in humans. Spermiogenesis extends over 22.7 days in rats and 21.6 days in humans. In this part, we review several key events that take place during the development of spermatids from a structural and functional point of view. During early spermiogenesis, the Golgi apparatus forms the acrosome, a lysosome-like membrane bound organelle involved in fertilization. The endoplasmic reticulum undergoes several topographical and structural modifications including the formation of the radial body and annulate lamellae. The chromatoid body is fully developed and undergoes structural and functional modifications at this time. It is suspected to be involved in RNA storing and processing. The shape of the spermatid head undergoes extensive structural changes that are species-specific, and the nuclear chromatin becomes compacted to accommodate the stream-lined appearance of the sperm head. Microtubules become organized to form a curtain or manchette that associates with spermatids at specific steps of their development. It is involved in maintenance of the sperm head shape and trafficking of proteins in the spermatid cytoplasm. During spermiogenesis, many genes/proteins have been implicated in the diverse dynamic events occurring at this time of development of germ cells and the absence of some of these have been shown to result in subfertility or infertility. Microsc. Res. Tech., 2010. © 2009 Wiley-Liss, Inc. [source] Functional importance of the actin cytoskeleton in contraction of bovine iris sphincter muscleAUTONOMIC & AUTACOID PHARMACOLOGY, Issue 3 2002J. A. C. Filipe Summary 1 The contractile capacity of smooth muscle cells depends on the cytoskeletal framework of the cell. The aim of this study was to determine the functional importance of both the actin and the tubulin components of the cytoskeleton in contractile responses of the bovine isolated iris sphincter muscle. 2 In each preparation, two contractions to the muscarinic agonist carbachol were obtained. The maximum responses of the first contractions were taken as 100%. The second contractions to carbachol were elicited in the presence of either cytochalasin B (50 and 5 ,m), an inhibitor of the actin cytoskeleton, or colchicine (100 ,m), an inhibitor of the tubulin cytoskeleton (30 min incubation). 3 Cytochalasin B, at a concentration of 50 ,m, significantly decreased the contractions induced by carbachol, with the maximum response reduced to 21.8 ± 6.6% (n = 12) of the initial maximum. The maximal contractions to carbachol in the presence of colchicine reached 96.2 ± 7.9% (n = 9) of the initial contraction, which was not significantly different from control second responses to carbachol with neither drug present, which reached 113.3 ± 7.6% (n = 7). 4 The effect of cytochalasin B was dose-dependent, since at a lower concentration of 5 ,m, the drug decreased the maximum contraction to carbachol to 60.3 ± 8.8% (n = 6). The effect of cytochalasin B was at least partially reversible, since after the use of the higher concentration of 50 ,m, contractions to carbachol increased to 62.3 ± 15.5% (n = 4) of the maximal response, after 1 h repeated washing of the preparations. 5 Cytochalasin D, at a concentration of 50 ,m, completely abolished the contractions induced by carbachol (n = 4). 6 These findings suggest that in bovine iris sphincter muscle, contractions to carbachol are highly dependent, from a functional point of view, on actin polymerization, and not, to any important degree, on the polymerization of tubulin. [source] Effect of voriconazole on a corneal abscess caused by fusariumACTA OPHTHALMOLOGICA, Issue 6 2004Anna Polizzi Abstract. Purpose:, To describe a case of corneal abscess caused by Fusarium solani that did not respond to common antifungal agents. Method:, Case report. Results:, Twenty days after accidental contact with vegetation, a 56-year-old man presented with a corneal abscess. Corneal ulceration developed and a perforating keratoplasty was performed. After a microbiological examination, the diagnosis of F. solani infection was made. Systemic and topical amphotericin B and fluconazole were prescribed, with no results. A new abscess formed on the transplanted graft and a wound leak developed. We administered topical and systemic voriconazole. No side-effects were observed. The choroidal detachment and the surgical transplant recovered completely in 20 days. A vascular leukoma developed at the site of the transplanted corneal abscess. Conclusion:, From a functional point of view, another corneal transplant will be necessary. Voriconazole was effective in treating a severe keratomycosis caused by F. solani that was resistant to other topical and systemic antifungal agents. [source] | ||||||||||