82 research outputs found

    The Constraint Interpretation of Physical Emergence

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    I develop a variant of the constraint interpretation of the emergence of purely physical (non-biological) entities, focusing on the principle of the non-derivability of actual physical states from possible physical states (physical laws) alone. While this is a necessary condition for any account of emergence, it is not sufficient, for it becomes trivial if not extended to types of constraint that specifically constitute physical entities, namely, those that individuate and differentiate them. Because physical organizations with these features are in fact interdependent sets of such constraints, and because such constraints on physical laws cannot themselves be derived from physical laws, physical organization is emergent. These two complementary types of constraint are components of a complete non-reductive physicalism, comprising a non-reductive materialism and a non-reductive formalism

    Proteomic and Metabolomic Characteristics of Extremophilic Fungi Under Simulated Mars Conditions

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    Filamentous fungi have been associated with extreme habitats, including nuclear power plant accident sites and the International Space Station (ISS). Due to their immense adaptation and phenotypic plasticity capacities, fungi may thrive in what seems like uninhabitable niches. This study is the first report of fungal survival after exposure of monolayers of conidia to simulated Mars conditions (SMC). Conidia of several Chernobyl nuclear accident-associated and ISS-isolated strains were tested for UV-C and SMC sensitivity, which resulted in strain-dependent survival. Strains surviving exposure to SMC for 30 min, ISSFT-021-30 and IMV 00236-30, were further characterized for proteomic, and metabolomic changes. Differential expression of proteins involved in ribosome biogenesis, translation, and carbohydrate metabolic processes was observed. No significant metabolome alterations were revealed. Lastly, ISSFT-021-30 conidia re-exposed to UV-C exhibited enhanced UV-C resistance when compared to the conidia of unexposed ISSFT-021

    Ordering and magnetic after-effect in micro- and polycrystalline Fe-6.5%Si samples

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    The microstructure and disaccommodation of the magnetic susceptibility for micro- and polycrystalline Fe-6.5%Si samples (with initially different order) aged at 973 K were studied. It is stated that ageing the sample in which initially the short range order occurrs, leads to the appearance of the Fe-Si structure. This is accompanied by the increase of the disaccommodation amplitude. The isochronal disaccommodation curves were decomposed into five elementary processes and their activation energies were calculated

    Structure evolution and magnetic properties of annealed Fe77-x-yCuxNbySi13B10 alloys

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    The microstructure and magnetic properties of the amorphous and partially crystallized Fe77-x-yCuxNbySi13B10 (x=0 or 1 and y=0, 1, 2 or 3) ribbons were investigated. From Mössbauer spectroscopy investigations it was stated that the half linewidth in Zeeman sextets corresponding to very fine α-FeSi grains is larger than that observed in the crystalline alloys which is caused by the interface effect. Moreover, the off-plane anisotropy is observed after annealing the Fe75Cu1Nb1Si13B10 ribbon at 693 K. This may be attributed to the nucleation of α-FeSi grains in the ribbon surface. The excellent soft magnetic properties were obtained for the Fe-based nanocrystalline alloy with additives of 1 % Cu and 2 or 3% of Nb

    Characterization of Aspergillus niger Isolated from the International Space Station.

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    The initial characterization of the Aspergillus niger isolate JSC-093350089, collected from U.S. segment surfaces of the International Space Station (ISS), is reported, along with a comparison to the extensively studied strain ATCC 1015. Whole-genome sequencing of the ISS isolate enabled its phylogenetic placement within the A. niger/welwitschiae/lacticoffeatus clade and revealed that the genome of JSC-093350089 is within the observed genetic variance of other sequenced A. niger strains. The ISS isolate exhibited an increased rate of growth and pigment distribution compared to a terrestrial strain. Analysis of the isolate's proteome revealed significant differences in the molecular phenotype of JSC-093350089, including increased abundance of proteins involved in the A. niger starvation response, oxidative stress resistance, cell wall modulation, and nutrient acquisition. Together, these data reveal the existence of a distinct strain of A. niger on board the ISS and provide insight into the characteristics of melanized fungal species inhabiting spacecraft environments. IMPORTANCE A thorough understanding of how fungi respond and adapt to the various stimuli encountered during spaceflight presents many economic benefits and is imperative for the health of crew. As A. niger is a predominant ISS isolate frequently detected in built environments, studies of A. niger strains inhabiting closed systems may reveal information fundamental to the success of long-duration space missions. This investigation provides valuable insights into the adaptive mechanisms of fungi in extreme environments as well as countermeasures to eradicate unfavorable microbes. Further, it enhances understanding of host-microbe interactions in closed systems, which can help NASA's Human Research Program maintain a habitat healthy for crew during long-term manned space missions

    The International Space Station Environment Triggers Molecular Responses in Aspergillus niger.

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    Due to immense phenotypic plasticity and adaptability, Aspergillus niger is a cosmopolitan fungus that thrives in versatile environments, including the International Space Station (ISS). This is the first report of genomic, proteomic, and metabolomic alterations observed in A. niger strain JSC-093350089 grown in a controlled experiment aboard the ISS. Whole-genome sequencing (WGS) revealed that ISS conditions, including microgravity and enhanced irradiation, triggered non-synonymous point mutations in specific regions, chromosomes VIII and XII of the JSC-093350089 genome when compared to the ground-grown control. Proteome analysis showed altered abundance of proteins involved in carbohydrate metabolism, stress response, and cellular amino acid and protein catabolic processes following growth aboard the ISS. Metabolome analysis further confirmed that space conditions altered molecular suite of ISS-grown A. niger JSC-093350089. After regrowing both strains on Earth, production of antioxidant-Pyranonigrin A was significantly induced in the ISS-flown, but not the ground control strain. In summary, the microgravity and enhanced irradiation triggered unique molecular responses in the A. niger JSC-093350089 suggesting adaptive responses
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