5,447 research outputs found
Virtual porous materials to predict the air void topology and hydraulic conductivity of asphalt roads
This paper investigates the effects of air void topology on hydraulic conductivity in asphalt mixtures with porosity in the range 14%–31%. Virtual asphalt pore networks were generated using the Intersected Stacked Air voids (ISA) method, with its parameters being automatically adjusted by the means of a differential evolution optimisation algorithm, and then 3D printed using transparent resin. Permeability tests were conducted on the resin samples to understand the effects of pore topology on hydraulic conductivity. Moreover, the pore networks generated virtually were compared to real asphalt pore networks captured via X-ray Computed Tomography (CT) scans. The optimised ISA method was able to generate realistic 3D pore networks corresponding to those seen in asphalt mixtures in term of visual, topological, statistical and air void shape properties. It was found that, in the range of porous asphalt materials investigated in this research, the high dispersion in hydraulic conductivity at constant air void content is a function of the average air void diameter. Finally, the relationship between average void diameter and the maximum aggregate size and gradation in porous asphalt materials was investigated
Liquid crystal anchoring transitions on aligning substrates processed by plasma beam
We observe a sequence of the anchoring transitions in nematic liquid crystals
(NLC) sandwiched between the hydrophobic polyimide substrates treated with the
plasma beam. There is a pronounced continuous transition from homeotropic to
low tilted (nearly planar) alignment with the easy axis parallel to the
incidence plane of the plasma beam (the zenithal transition) that takes place
as the exposure dose increases. In NLC with positive dielectric anisotropy, a
further increase in the exposure dose results in in-plane reorientation of the
easy axis by 90 degrees (the azimuthal transition). This transition occurs
through the two-fold degenerated alignment characteristic for the second order
anchoring transitions. In contrast to critical behavior of anchoring, the
contact angle of NLC and water on the treated substrates monotonically declines
with the exposure dose. It follows that the surface concentration of
hydrophobic chains decreases continuously. The anchoring transitions under
consideration are qualitatively interpreted by using a simple phenomenological
model of competing easy axes which is studied by analyzing anchoring diagrams
of the generalized polar and non-polar anchoring models.Comment: revtex4, 18 pages, 10 figure
CURVED PLANFORM WINGS WITH A HIGH ASPECT RATIO FOR AIRCRAFTS OPERATING IN THE TRANSONIC REGIME
The present invention concerns an innovative
wing (1) specific for an aircraft operating in the
transonic regime and comprising:
- A root section ;
- A tip section and;
- A leading edge for connecting the root section to the tip section.
In accordance with the invention, the curved leading edge is configured according to a line by
which locally the angle (Λ) formed by the forwarding direction of the wing and the perpendicular to the
tangent of the leading edge increases progressively from the root section to the tip section of the wing.
In such a way, the speed component (Vu) of the asymptotic flow orthogonal to the leading edge decreases
progressively from the root section to the tip section, thus reducing the local Mach number progressively
Towards a competitive and sustainable OA market in Europe - A study of the open access market and policy environment
Deliverable 5.3 of OpenAIRE WP5: FP7 Post Grant Gold Open Access Pilot.
This deliverable consists of a study and an annex - and it will be supplemented by a roadmap in May 2017.
This study considers the economic factors contributing to the current state of the open-access publishing market, and evaluates the potential for European policymakers to enhance market competition and sustainability in parallel to increasing access. It was commissioned within the scope of the OpenAIRE FP7 Post-Grant Open Access Pilot, and it will be accompanied by a Roadmap document developed with inputs from an expert workshop to be held in The Hague on 20 April 2017. In accordance with the project brief, the study aims to:
Explore the current status of the OA publishing market
Analyse existing OA publishing business models
Evaluate how different national and international policies are complementing each other as a means to achieve a transition to OA
Evaluate the impact of the Framework Programme 7 Post-grant OA pilot and its implications for future similar initiatives and the transition to OA.
Provide a roadmap leading to a sustainable and competitive market
The transition to open access concerns all kinds of academic research outputs, including monographs, journal articles, and data. This study focuses on open access to peer-reviewed research articles, which constitute the bulk of the market and the primary mechanism through which research is disseminated across disciplinary communities and beyond.
This report is supplemented by an Annex containing a mid-term evaluation of the FP7 Post-Grant Open Access Pilot.This report will be accompanied by a Roadmap document developed with inputs from an expert workshop to be held in The Hague on 20 April 201
A New Configuration of Vertical Axis Wind Turbine: Towards the Development of a highly distributed and efficient Wind Power Generation
Preliminary results obtained for a new configuration lift based vertical-axis wind turbine are shown. The turbine rotor is a cross flow fan type made with high curvature aerodynamic profiles. A reduced scale model of the turbine rotor has been designed and preliminary tested at the Department of Aerospace Engineering of the University of Pisa (rotor diameter 250 mm, rotor height 210 mm). The reduced scale model shows an efficiency of about eighteen per cent. The rotor is of a self-starting type. Two-dimensional CFD analyses have been performed applying both the Moving Reference Frame and the Moving Mesh conditions to the grid which surrounds the rotor blades (Fluent® Rel. 6.3 and STAR-CCM+® Rel. 6.04 have been used). Noticeable scale effects have been found numerically, so, the efficiency of a full scale lift based vertical axis multi-blades optimized wind turbine is expected to be comparable with lift based horizontal-axis wind turbines
MITOCHONDRIAL MASS, DISTRIBUTION AND ACTIVITY DURING SEA URCHIN OOGENESIS
The sea urchin egg is a favourite model for studies of the molecular biology and physiology of fertilization and early development, yet we know sparingly little of its oocytes and of mitochondria behaviour during oogenesis.
The process of oogenesis in most echinoderms is asynchronous so each ovary lobe has hundreds of oocytes at all stages of development. At the beginning of oogenesis, the oocyte is about 10 \ub5m in diameter. During the vitellogenic phase of oogenesis, the oocyte accumulate yolk proteins and grow to ten times their original size to 80 to 100 \ub5m in sea urchins. The oocyte, arrested at the prophase of the first meiotic division, is apparent with its large nucleus, the germinal vesicle (GV), containing a prominent nucleolus. Echinoid (such as sea urchin) and Holothurian oocytes complete meiotic maturation prior to fertilization, distinct from other echinoderms and almost all others animals. As maturation progresses, it occurs the GV breaks down (GVBD). These eggs may then be stored for weeks to months within the female before they are spawned, and the proportion of eggs in the ovary increases from early to late season, as the numbers of oocytes decline [1].
Mitochondria, generally known as the powerhouses of eukaryotic cells, play a primary role in cellular energetic metabolism, homeostasis and death. These organelles, with their multicopy genome maternally inherited, are directly involved at several levels in the reproductive process since their functional status influences the quality of oocytes and contributes to the process of fertilization and embryonic development.
It has been demonstrated that the number of maternal mitochondria is sufficient to support development until late stages without new synthesis of mitochondrial DNA or production of new organelles [2]. During embryogenesis mitochondrial mass does not change, whereas mitochondrial respiration increases [3]. The behaviour of these organelles during oogenesis remains at moment unclear.
In the present paper we studied, by Confocal Laser Scanning Microscopy tecnologies (CLSM), the mass and distribution, the activity and the DNA content of sea urchin Paracentrotus lividus mitochondria during oogenesis, by in vivo incubating oocytes of different size with cell-permeant probes specific for mitochondria and for DNA and by immunodetection of hsp60 chaperonine, a well known mitochondrial marker.
In particular the oocytes were grouped in six classes: < 10, 20/30, 40/50, 60/70, 80/90 \ub5m, and 90 \ub5m ovulated egg, on the base of diameters. Microscopic observations were performed capturing 2 \ub5m thick layers of oocytes. Of the several thousands oocytes we observed, 20 for each different oogenesis stage were analyzed and processed. In order to interpret results and to draw unequivocal conclusions, we measured by IMAGE J software analysis the intensity values of fluorescent signals, as suggested in Agnello et al 2008 [4].
The mitochondria of oocytes with a diameter between 20 and 70 \ub5m, appeared to give rise to clusters that disappear in that of 80 \ub5m. In the oocytes between 60 and 90 \ub5m the red fluorescence seems to be more evident around the germinal vesicle (the merge tends to red), suggesting an increasing oxidative phosphorylation activity.
In the ovulated eggs, red and green fluorescence are uniformly distributed suggesting that mitochondria are dispersed in the cytoplasm. In addition the merge of green and red colours shows that the whole mitochondrial population is consuming oxygen at the same level (the resulting colours tends to yellow), figure 1.
In order to calculate the total mitochondrial mass and activity we integrated the values of pixel intensities for all captured sections and used the arithmetic means to draw a statistical analysis. Results suggest a parallel rise of mitochondrial mass and activity, suggesting that the amount and activity of organelles change remarkably during oogenesis.
Figure 1. shows the distribution of hsp60 protein, detected by immunofluorescence analysis (A), the mitochondrial and genomic DNA, after in vivo incubation with PicoGreen probe (B) and the merge of green and red fluorescence signal, respectively due to mitochondrial mass and activity, after in vivo incubation with Mitotraker Green and Orange (C). The size of the oocytes reported is 80 \ub5m.
Results suggest that mitochondria are actively duplicating and that mitochondrial DNA is replicating during the different oogenesis phases. It is noteworthy that around the germinal vesicle, especially in the larger oocytes, next to the germinal vesicle breakdown, the organelles are more active in oxygen consumption, probably due to the major energetic needing in this key moment of gametogenesis.
[1] Wessel G.M., Voronina E., and Brooks J.M. (2004) Obtaining and handling echinoderm oocytes. In \u201cMethods in Cell Biology\u201d, Elsevier. Vol.74, Chapter 5, pp. 87-114.
[2] Matsumoto L., Kasamatsu H., Pik\ub4o L. and Vinograd J. (1974) Mitochondrial DNA replication in sea urchin oocytes. J. Cell Biol. 63: 146\u2013159.
[3] Morici G., Agnello M., Spagnolo F., Roccheri M.C., Di Liegro C.M. and Rinaldi A.M. (2007) Confocal microscopy study of the distribution, content and activity of mitochondria during Paracentrotus lividus development. Journal of Microscopy. 228: 165-173.
[4] Agnello M., Morici G., Rinaldi A.M. (2008) A method for measuring mitochondrial mass and activity . Cytotechnology. 56: 145-149.
Maria Carmela Roccheri: Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche. Universit\ue0 degli Studi di Palermo, Viale delle Scienze Ed.16, Palermo, Italy; tel: 09123897414;
e-mail: [email protected]
Functionalization of Organic Semiconductor Crystals via the Diels-Alder Reaction
A surface adlayer is generated on organic single crystals (tetracene and rubrene) using the site specific Diels–Alder reaction and a series of vapor phase dienophiles. X-ray photoelectron spectroscopy (XPS) confirms adsorption on the surfaces of tetracene and rubrene and mass spectrometry demonstrates the reaction’s applicability to a range of dienophiles
Bionanotechnology and the Future of Glioma
Designer nanoscaled materials have the potential to revolutionize diagnosis and treatment for glioma. This review summarizes current progress in nanoparticle‑based therapies for glioma treatment including targeting, drug delivery, gene delivery, and direct tumor ablation. Preclinical and current human clinical trials are discussed. Although progress in the field has been significant over the past decade, many successful strategies demonstrated in the laboratory have yet to be implemented in human clinical trials. Looking forward, we provide examples of combined treatment strategies, which harness the potential for nanoparticles to interact with their biochemical environment, and simultaneously with externally applied photons or magnetic fields. We present our notion of the “ideal” nanoparticle for glioma, a concept that may soon be realized
JAHA, a novel histone deacetylase inhibitor: cytotoxic effect on triple-negative breast cancer cells
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