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  • 1
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    Understanding constitutive COX-2 expression [Pharmacology] (2016)
    National Academy of Sciences
    Details
    Publication Date: 2016-01-13
    Description: Cyclooxygenase-2 (COX-2) is an inducible enzyme that drives inflammation and is the therapeutic target for widely used nonsteroidal antiinflammatory drugs (NSAIDs). However, COX-2 is also constitutively expressed, in the absence of overt inflammation, with a specific tissue distribution that includes the kidney, gastrointestinal tract, brain, and thymus. Constitutive COX-2 expression...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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  • 2
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    Ecological interactions are evolutionarily conserved across the entire tree of life (2010)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2010-06-04
    Description: Ecological interactions are crucial to understanding both the ecology and the evolution of organisms. Because the phenotypic traits regulating species interactions are largely a legacy of their ancestors, it is widely assumed that ecological interactions are phylogenetically conserved, with closely related species interacting with similar partners. However, the existing empirical evidence is inadequate to appropriately evaluate the hypothesis of phylogenetic conservatism in ecological interactions, because it is both ecologically and taxonomically biased. In fact, most studies on the evolution of ecological interactions have focused on specialized organisms, such as some parasites or insect herbivores, belonging to a limited subset of the overall tree of life. Here we study the evolution of host use in a large and diverse group of interactions comprising both specialist and generalist acellular, unicellular and multicellular organisms. We show that, as previously found for specialized interactions, generalized interactions can be evolutionarily conserved. Significant phylogenetic conservatism of interaction patterns was equally likely to occur in symbiotic and non-symbiotic interactions, as well as in mutualistic and antagonistic interactions. Host-use differentiation among species was higher in phylogenetically conserved clades, irrespective of their generalization degree and taxonomic position within the tree of life. Our findings strongly suggest a shared pattern in the organization of biological systems through evolutionary time, mediated by marked conservatism of ecological interactions among taxa.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gomez, Jose M -- Verdu, Miguel -- Perfectti, Francisco -- England -- Nature. 2010 Jun 17;465(7300):918-21. doi: 10.1038/nature09113. Epub 2010 Jun 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Departamento de Ecologia, Universidad de Granada, E-18071 Granada, Spain. jmgreyes@ugr.es〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20520609" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biological Evolution ; *Ecosystem ; Host-Parasite Interactions ; *Phylogeny ; Symbiosis/*physiology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 3
    Electronic Resource
    Electronic Resource
    A Diffusion Model for Sword in Sheath Failure Mode in Vapour Grown Carbon Fibers (1997)
    Springer
    Advanced performance materials 4 (1997), S. 305-315 
    Details
    ISSN: 1572-8765
    Keywords: carbon fibers failure mode ; diffusion coefficient of hydrogen in carbon fibers ; hydrogen diffusion in vapour grown carbon fibers ; hydrogenation of carbon fibers ; vapour grown carbon fibers hardening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A peculiar failure mode named “sword in sheath” was reported in previous studies on Vapour Grown Carbon Fibers (VGCFs). It consists in a gliding between the VGCFs catalytic hard core and pyrolitic soft coating. This is a very interesting failure mode, looking to the additional work of fracture that it supposes. After knowing that the main difference between the hard core and the soften cortical carbon is the hydrogen content, some attempts of increase the hydrogen content in the cortical phase are made at the present work via annealing in a pure hydrogen atmosphere. A mathematical model is set up to describe the different phenomena that take place during the annealing. The hydrogen comes to the cortical carbon from the atmosphere and from the inner core. As a consequence of the very significant gradient of hydrogen concentration in the surrounding of the interface core—cortical phase, a shear mechanism is possible under tensile stress. For this reason sword in sheath takes place, mainly in not very thick fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008629222372
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  • 4
    Electronic Resource
    Electronic Resource
    Number of adult female mites Varroa jacobsoni Oud. on hive debris from honey bee colonies artificially infested to monitor mite population increase (Mesostigmata: Varroidae) (1995)
    Springer
    Experimental and applied acarology 19 (1995), S. 181-188 
    Details
    ISSN: 1572-9702
    Keywords: Honey bees ; Apis mellifera ; Varroa jacobsoni ; hive debris ; population growth rates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Six honey bee colonies hived in Langstroth nuclei were each artificially infested with 100 phoretic Varroa mites. Hive debris on bottom inserts was inspected every 3–4 days. The adult Varroa mites were compared with mounted specimens and catalogued into lightly pigmented and darkly pigmented females. After 4 months, an acaricide treatment was used to estimate the final mite population. Based on light and dark adult counts, we propose a balancing equation that follows the Varroa population increase at 7 day intervals and allows the calculation of experimental population growth rates. The calculated Varroa finite rate of increase is λ=1.021. Exponential and logistic growth models fitted to the balancing equation data gave R 2=0.986 and R 2=0.991, respectively. To develop a more precise model it would be necessary to follow the population growth beyond our experimental data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046290
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  • 5
    Electronic Resource
    Electronic Resource
    Hive debris counts in honeybee colonies: a method to estimate the size of small populations and rate of growth of the miteVarroa jacobsoni Oud. (Mesostigmata: Varroidae) (1993)
    Springer
    Experimental and applied acarology 17 (1993), S. 889-894 
    Details
    ISSN: 1572-9702
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fifteen honeybee colonies (Apis mellifera L.) infested with the ectoparasiteVarroa jacobsoni Oud. were monitored for the number of mites falling to the bottom of the hive. Mites in the debris were counted periodically on the plastic sheet on which they were collected. Two months later, colonies were treated with an acaricide to determine mite population. A high positive correlation was found between the number of mites collected in the hive debris over different periods and the final population size. Based on this correlation, it was possible to use hive debris counts to predict the degree of infestation. Furthermore, counting fallen mites over a period of two months, followed by an acaricide treatment, might be a useful method of estimating the rate of growth ofV. jacobsoni in honeybee colonies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02328065
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  • 6
    Electronic Resource
    Electronic Resource
    Survival of the mite Varroa jacobsoni Oud. (Mesostigmata: Varroidae) in broodless colonies of the honey bee Apis mellifera L. (Hymenoptera: Apidae) (1994)
    Springer
    Experimental and applied acarology 18 (1994), S. 603-612 
    Details
    ISSN: 1572-9702
    Keywords: Honey bees ; Apis mellifera ; Varroa jacobsoni ; Survival ; Life expectancy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Varroa mite free colonies of the honey bee Apis mellifera L. were artificially infested, with either parasitized bees or infested worker brood. Queens were kept in cages to provide broodless conditions during the experiment. Parasites that fell to the bottom of the hive were monitored at 3–4 days intervals for three months. An acaricide treatment was used to recover mites still alive after this time period. Survivorship at each interval was calculated and life table functions of the phoretic mite cohorts were obtained. Trends in survival of Varroa cohorts showed maximum lifespans ranging from 80 to 100 days. Life expectancy of these phoretic cohorts at the beginning of the experiment ranges between 19 to 41, with a mean of 31 days.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00051723
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  • 7
    Electronic Resource
    Electronic Resource
    Some microstructural aspects of vapour-grown carbon fibres to disclose their failure mechanisms (1996)
    Springer
    Journal of materials science 31 (1996), S. 6189-6193 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The microstructure of vapour-grown carbon fibres has been studied by an SEM examination of the transverse section. In this way the duplex structure, of catalytic and pyrolytic carbon, can be differentiated by the fracture of each phase; pyrolytic carbon shows concentric circles, termed tree trunk structure, while a glassy appearance characterizes the pyrolytic phase. It was observed that fracture was strongly influenced by the breaking mode of the fibre, because in tensile failure of a thick fibre, fracture similar to the tree trunk appearance can be formed in the outer layer of the pyrolytic phase. Thus it is necessary to study the transverse microstructure of vapour-grown carbon fibres without any failure process. Using a preparation of fibre samples, in slides as thin as necessary for TEM study, the internal structure was disclosed. The pyrolytic phase was constituted of randomly oriented small crystals, while the tree trunk structure was really formed by very elongated crystals with preferential orientation. Electron diffraction of both phases shows a different degree of texture according to the structures. In addition to crystals, TEM examination showed the existence of hollow cavities, that have a clear influence on the failure mechanism. Owing to these faults, the failure process forms parallel grooves, that constitute the tree trunk appearance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00354437
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  • 8
    Electronic Resource
    Electronic Resource
    Study by a modified scanning electron microscope fractography of hydrogenation process in vapour grown carbon fibres (1998)
    Springer
    Journal of materials science 33 (1998), S. 2079-2085 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The present paper intends to study the microstructure of vapour grown carbon fibres (VGCF), whose fracture depends on the breaking mode, as it was stated. Before being examined, transversal sections of fibres were etched, using an argon ion beam, aiming to remove a thin surfacial layer, then seriously altered by the failure process. After that, based upon the results of the scanning electron microscopy (SEM) examination, it can be established that the inner core of as-grown VGCF is constituted by a Rowland's structure. Although differentiated crystals do not exist in the cortical phase, the boundary between the core and the latter phase is clearly observable. After that, an overhydrogenation process took place as a result of an annealing of the fibres in a hydrogen atmosphere. The microstructure had been, by then, slightly modified. In the inner core, not only the gap width between crystals had been modified but the boundary between catalytical and pyrolytical phases had vanished as well. As a consequence of such modifications, the fibres Young's modulus increases and their failure strain diminishes, in a similar manner as the mechanical properties of current ex-polyacrylonitrile (PAN) carbon fibres are altered by graphitization, during a graphitizing process. © 1998 Chapman & Hall
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004362901697
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  • 9
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    Centrality in primate-parasite networks reveals the potential for the transmission of emerging infectious diseases to humans (2013)
    National Academy of Sciences
    Details
    Publication Date: 2013-04-22
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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  • 10
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    Study by a modified scanning electron microscope fractography of hydrogenation process in vapour grown carbon fibres (1998)
    Springer
    Details
    Publication Date: 1998-04-01
    Print ISSN: 0022-2461
    Electronic ISSN: 1573-4803
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Springer
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