30 research outputs found

    Panel I: Connecting 2nd Law Analysis with Economics, Ecology and Energy Policy

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    The present paper is a review of several papers from the Proceedings of the Joint European Thermodynamics Conference, held in Brescia, Italy, 1–5 July 2013, namely papers introduced by their authors at Panel I of the conference. Panel I was devoted to applications of the Second Law of Thermodynamics to social issues—economics, ecology, sustainability, and energy policy. The concept called Available Energy which goes back to mid-nineteenth century work of Kelvin, Rankine, Maxwell and Gibbs, is relevant to all of the papers. Various names have been applied to the concept when interactions between the system of interest and an environment are involved. Today, the name exergy is generally accepted. The scope of the papers being reviewed is wide and they complement one another well

    Identification of the critical replication targets of CDK reveals direct regulation of replication initiation factors by the embryo polarity machinery in C. elegans

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    During metazoan development, the cell cycle is remodelled to coordinate proliferation with differentiation. Developmental cues cause dramatic changes in the number and timing of replication initiation events, but the mechanisms and physiological importance of such changes are poorly understood. Cyclin-dependent kinases (CDKs) are important for regulating S-phase length in many metazoa, and here we show in the nematode Caenorhabditis elegans that an essential function of CDKs during early embryogenesis is to regulate the interactions between three replication initiation factors SLD-3, SLD-2 and MUS-101 (Dpb11/TopBP1). Mutations that bypass the requirement for CDKs to generate interactions between these factors is partly sufficient for viability in the absence of Cyclin E, demonstrating that this is a critical embryonic function of this Cyclin. Both SLD-2 and SLD-3 are asymmetrically localised in the early embryo and the levels of these proteins inversely correlate with S-phase length. We also show that SLD-2 asymmetry is determined by direct interaction with the polarity protein PKC-3. This study explains an essential function of CDKs for replication initiation in a metazoan and provides the first direct molecular mechanism through which polarization of the embryo is coordinated with DNA replication initiation factors

    Seasonal encounter rates and residency patterns of an unstudied population of bottlenose dolphin (Tursiops truncatus) in the northwestern Levantine Sea, Turkey

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    Insufficient data regarding abundance, distribution and movement patterns of bottlenose dolphins has contributed to lack of effective conservation strategies within the Levantine Sea. It has been inferred that the bottlenose dolphin population has decreased by 30 % in the last 60 years, thus a basin wide research effort on the population is an urgent priority. We present the preliminary results of the first bottlenose dolphin photo-identification study in the northwestern Levantine Sea. 32 boat surveys were conducted from March 2015 to July 2016, totalling 1433 km of survey effort. Current study reported an uneven distribution, high seasonal encounters and varied residency patterns of bottlenose dolphins within the northwestern Levantine Sea. We propose that the northwestern Levantine Sea, specifically the coastal waters of Antalya Bay, indeed is an important bottlenose dolphin habitat and adjacent waters may be of similar significance. Of the 56 individuals catalogued, 13 were re-sighted in both years. Encounter rates varied seasonally, with a peak in spring of 12 groups and 100 individuals per 100 km. Dolphin presence was not detected during autumn and winter. While seasonal, visitor and transient dolphins were reported, no year-round residency was documented. Incidental observations of visible starvation signs and skin parasites suggested individual dolphins in this region could be under anthropogenic stressors. The results reported here highlight the importance of baseline information on encounter rate, distribution and residency pattern as they have a key role on the assessment of population statues and the threats they are facing. Future studies with annual survey effort, have to be continued in the northwestern Levantine Sea and its adjacent waters

    Pathogenic NR2F1 variants cause a developmental ocular phenotype recapitulated in a mutant mouse model.

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    Pathogenic NR2F1 variants cause a rare autosomal dominant neurodevelopmental disorder referred to as the Bosch-Boonstra-Schaaf Optic Atrophy Syndrome. Although visual loss is a prominent feature seen in affected individuals, the molecular and cellular mechanisms contributing to visual impairment are still poorly characterized. We conducted a deep phenotyping study on a cohort of 22 individuals carrying pathogenic NR2F1 variants to document the neurodevelopmental and ophthalmological manifestations, in particular the structural and functional changes within the retina and the optic nerve, which have not been detailed previously. The visual impairment became apparent in early childhood with small and/or tilted hypoplastic optic nerves observed in 10 cases. High-resolution optical coherence tomography imaging confirmed significant loss of retinal ganglion cells with thinning of the ganglion cell layer, consistent with electrophysiological evidence of retinal ganglion cells dysfunction. Interestingly, for those individuals with available longitudinal ophthalmological data, there was no significant deterioration in visual function during the period of follow-up. Diffusion tensor imaging tractography studies showed defective connections and disorganization of the extracortical visual pathways. To further investigate how pathogenic NR2F1 variants impact on retinal and optic nerve development, we took advantage of an Nr2f1 mutant mouse disease model. Abnormal retinogenesis in early stages of development was observed in Nr2f1 mutant mice with decreased retinal ganglion cell density and disruption of retinal ganglion cell axonal guidance from the neural retina into the optic stalk, accounting for the development of optic nerve hypoplasia. The mutant mice showed significantly reduced visual acuity based on electrophysiological parameters with marked conduction delay and decreased amplitude of the recordings in the superficial layers of the visual cortex. The clinical observations in our study cohort, supported by the mouse data, suggest an early neurodevelopmental origin for the retinal and optic nerve head defects caused by NR2F1 pathogenic variants, resulting in congenital vision loss that seems to be non-progressive. We propose NR2F1 as a major gene that orchestrates early retinal and optic nerve head development, playing a key role in the maturation of the visual system

    Organotypic modelling as a means of investigating epithelial-stromal interactions during tumourigenesis

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    The advent of co-culture approaches has allowed researchers to more accurately model the behaviour of epithelial cells in cell culture studies. The initial work on epidermal modelling allowed the development of reconstituted epidermis, growing keratinocytes on top of fibroblasts seeded in a collagen gel at an air-liquid interface to generate terminally differentiated 'skin equivalents'. In addition to developing ex vivo skin sheets for the treatment of burns victims, such cultures have also been used as a means of investigating both the development and repair of the epidermis, in more relevant conditions than simple two-dimensional culture, but without the use of animals. More recently, by varying the cell types used and adjusting the composition of the matrix components, this physiological system can be adapted to allow the study of interactions between tumour cells and their surrounding stroma, particularly with regards to how such interactions regulate invasion. Here we provide a summary of the major themes involved in tumour progression and consider the evolution of the approaches used to study cancer cell behaviour. Finally, we review how organotypic models have facilitated the study of several key pathways in cancer development and invasion, and speculate on the exciting future roles for these models in cancer research

    Thermodynamics

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    The Relations between Entropy and Energy of Black-body Radiation

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    ABSTRACT The entropy content of electromagnetic ("blackbody") radiation at equilibrium in an enclosure is represented, on a per unit volume basis, by s = [4/3]aT 3 and the internal energy content by u = aT 4 , so s = [4/3]u/T. The entropy transfer rate S Ď„ associated with emission from the radiation is related to the internal energy trans-fer rate

    Gibbs Revisited

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    Available Energy-Part I: Gibbs Revisite
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