Evolution and Nucleosynthesis of Metal-Free Massive Stars

We calculate presupernova evolutions and supernova explosions of massive stars (M=13-25 Mo) for various metallicities. We find the following characteristic abundance patterns of nucleosynthesis in the metal-free (Pop III) stars. (1) The alpha-nuclei (from C to Zn) are more efficiently produced than other isotopes, and the abundance pattern of alpha-nuclei can be similar to the solar abundance. In particular, near solar ratios of alpha elements/Fe might be a signature of Pop III which could produce a large amount of Fe. (2) The abundance ratios of odd Z to even Z elements such as Na/Mg and Al/Mg become smaller for lower metallicity. However, these ratios almost saturate below Z <~ 10^{-5}, and [Na, Al/Mg] ~ - 1 for Pop III and low metal Pop II nucleosynthesis. This result is consistent with abundance pattern of metal poor stars, in which these ratios also saturate around -1. We suggest that these stars with the lowest [Na/Mg] or [Al/Mg] may contain the abundance pattern of Pop III nucleosynthesis. (3) Metal poor stars show interesting trends in the ratios of [Cr, Mn, Co/Fe]. We discuss that these trends are not explained by the differences in metallicity, but by the relative thickness between the complete and the incomplete Si burning layers. Large [Co/Fe] and small [Cr, Mn/Fe] values found in the observations are explained if mass cut is deep or if matter is ejected from complete Si burning layer in a form of a jet or bullets. (4) We also find that primary ^{14}N production occurs in the massive Pop III stars, because these stars have radiative H-rich envelopes so that the convective layer in the He-shell burning region can reach the H-rich region.Comment: 19 pages. To appear in the proceedings of the MPA/ESO conference ``The First Stars'' (August 4-7, 1999, Garching) ed. A. Weiss etal. (Springer

Human Resource Development in Africa

SMART Africa Manifesto was endorsed by all countries of African Union in 2014. African countries have cooperated to enable innovation, communication and advocacy, capacity building and resource mobilization through ICT. SMART Africa Steering Committee recommended that African space program proposal with Japan was implemented in cooperation with African Union on space developments for achieving Sustainable Development Goals continuously and synergistically in February 2018. The University of Tokyo and Japan Space Systems have cooperated to provide capacity building programs about micro-satellite developments and Earth observation satellite data analysis techniques to African young engineers. 2 optical cameras as a pseudo-multi-spectral were loaded on the planned Japanese 3U-size satellite, RWASAT-1. Those cameras were expected to acquire data for land degradation, deforestation, agriculture and other objects. Japan Space Systems has had training programs about Earth observation satellite data analyses with open and free GIS software and ASTER datasets. Using open and free software and datasets made participants analyze sustainably after the programs. When African young engineers have abilities to develop and operate micro-satellites and to analyze Earth observation satellite data, they also have abilities to expand and share their space technologies to African countries through SMART Africa for African developments in near future

Hypernova Nucleosynthesis and Implications for Cosmic Chemical Evolution

We examine the characteristics of nucleosynthesis in 'hypernovae', i.e., supernovae with very large explosion energies (\gsim 10^{52} ergs). Implications for the cosmic chemical evolution and the abundances in M82 are discussed.Comment: To appear in 'Cosmic Evolution' Conference at IAP, Paris, honoring Jean Audouze and Jim Truran, 13-17 Nov 200

Designing Hydrogen-Bonded Organic Frameworks (HOFs) with Permanent Porosity

Designing organic components that can be used to construct porous materials enables the preparation of tailored functionalized materials. Research into porous materials has seen a resurgence in the past decade as a result of finding of self-standing porous molecular crystals (PMCs). Particularly, a number of crystalline systems with permanent porosity that are formed by self-assembly through hydrogen bonding (H-bonding) have been developed. Such systems are called hydrogen-bonded organic frameworks (HOFs). Herein we systematically describe H-bonding patterns (supramolecular synthons) and molecular structures (tectons) that have been used to achieve thermal and chemical durability, a large surface area, and functions, such as selective gas sorption and separation, which can provide design principles for constructing HOFs with permanent porosity.This is the accepted version of the following article: Hisaki I., Xin C.,Takahashi K., et al. Designing Hydrogen-Bonded Organic Frameworks (HOFs) with Permanent Porosity. Angewandte Chemie - International Edition 58, 11160 (2019), which has been published in final form at https://doi.org/10.1002/anie.201902147. This article may be used for non-commercialpurposes in accordance with the Wiley Self-ArchivingPolicy [https://authorservices.wiley.com/author-resources/Journal-Authors/licensing/self-archiving.html

Oral pathobiont induces systemic inflammation and metabolic changes associated with alteration of gut microbiota.

Periodontitis has been implicated as a risk factor for metabolic disorders such as type 2 diabetes, atherosclerotic vascular diseases, and non-alcoholic fatty liver disease. Although bacteremias from dental plaque and/or elevated circulating inflammatory cytokines emanating from the inflamed gingiva are suspected mechanisms linking periodontitis and these diseases, direct evidence is lacking. We hypothesize that disturbances of the gut microbiota by swallowed bacteria induce a metabolic endotoxemia leading metabolic disorders. To investigate this hypothesis, changes in the gut microbiota, insulin and glucose intolerance, and levels of tissue inflammation were analysed in mice after oral administration of Porphyromonas gingivalis, a representative periodontopathogens. Pyrosequencing revealed that the population belonging to Bacteroidales was significantly elevated in P. gingivalis-administered mice which coincided with increases in insulin resistance and systemic inflammation. In P. gingivalis-administered mice blood endotoxin levels tended to be higher, whereas gene expression of tight junction proteins in the ileum was significantly decreased. These results provide a new paradigm for the interrelationship between periodontitis and systemic diseases

Impaired alignment of bone matrix microstructure associated with disorganized osteoblast arrangement in malignant melanoma metastasis

Malignant melanoma favors spreading to bone, resulting in a weakened bone with a high fracture risk. Here, we revealed the disorganized alignment of apatite crystals in the bone matrix associated with the homing of cancer cells by developing an artificially controlled ex vivo melanoma bone metastasis model. The ex vivo metastasis model reflects the progressive melanoma cell activation in vivo, resulting in decreased bone mineral density and expression of MMP1-positive cells. Moreover, less organized intercellular connections were observed in the neighboring osteoblasts in metastasized bone, indicating the abnormal and randomized organization of bone matrix secreted by disconnected osteoblasts. Our study revealed that the deteriorated microstructure associated with disorganized osteoblast arrangement was a determinant of malignant melanoma-related bone dysfunction.Matsugaki A., Kimura Y., Watanabe R., et al. Impaired alignment of bone matrix microstructure associated with disorganized osteoblast arrangement in malignant melanoma metastasis. Biomolecules, 11, 2, 1. https://doi.org/10.3390/biom11020131