Rare-earth transition-metal intermetallics: structure-bonding-property relationships

The purpose of this thesis is to explore novel rare-earth, transition metal compounds and to investigate their structure and bonding and how these influence their properties. We have focused on the synthesis, characterization and electronic structure investigations, as well as physical properties of ternary rare-earth Fe-rich intermetallics, e.g., LaFe13-xSi x, and RE2-xFe4Si14-y, etc;The LaFe13-xSix, (1.0 ≤ x ≤ 5.0) compounds with structures related to the cubic NaZn13type are an important series of compounds to study for possible efficient magnetic refrigeration. A systematic structural study of the compositional variation in LaFe 13-xSix exhibits a structural transformation from the cubic NaZn13-structure type to a tetragonal derivative due to preferential ordering of Fe and Si atoms. Temperature-dependent single crystal X-ray diffraction at various temperatures and electronic structure calculations (both Extended Huckel and TB-LMTO) was performed on the cubic phases to examine the origin of the large magnetic entropy change. The giant magnetocaloric effect of cubic LaFe13-xSix alloys results from coupling between magnetic ordering and structural transformation;In light of the potential superstructures that could be observed for RE2-xFe4Si14-y as well as possible modifications of semiconducting beta-FeSi2, we report herein a thorough examination of the chemical composition and structure of RE2-xFe 4Si14-y (RE = Y, Gd-Lu) using a combination of electron microscopy and X-ray diffraction, and demonstrate a new superstructure for this class of compound. The structures are built up of rare-earth silicide planes with approximate compositions RE1.2Si1.9 alternating with beta-FeSi2-derived (hkl)-type slabs. Investigation by transition electron microscopy (TEM) reveals a superstructure in the crystallographic ab-plane. Fe Mossbauer spectra confirm two different iron environments in superstructure. Magnetic susceptibilities suggest weak magnetic coupling between rare-earth elements, and resistance measurements indicate poor metallic behavior with a large residual resistivity at low temperatures, which is consistent with disorder. Electronic structure calculations on model structures identify a pseudogap in the densities of states for specific valence electron counts that helps to provide a useful electron counting scheme for this class of rare-earth/transition metal/main group compound

Eco-Innovation Indices as Tools for Measuring Eco-Innovation

Measuring eco-innovation helps us understand the overall trends and raises awareness in society. Measuring eco-innovation at the national level and making comparisons across countries may allow us to benchmark performance and foster policy learning. This paper assesses two indices developed in two different regions: The ASEM Eco-Innovation Index (ASEI) by the ASEM SMEs Eco-Innovation Center, based in Republic of Korea; and the Eco-Innovation Scoreboard (Eco-IS) developed by the Eco-Innovation Observatory, based in the European Union. This paper aims to examine and compare the features of both and attempts to obtain insights on their strengths and weaknesses. Towards this aim, our paper assesses those scoreboards against four criteria stemming from innovation analysis: (1) relevance of areas and stakeholders covered; (2) ability to indicate changes; (3) directions towards common goals; and (4) ability to facilitate further changes. We conclude both are promising, despite data shortages, and have great potential to contribute towards the sustainable development goals (SDGs), particularly with regard to the SDGs on sustainable industrialization and sustainable consumption and production. In comparison, the ASEI covers more countries than the Eco-IS. However, the ASEI has limitations on measuring indicators due to limited data availability in Asian countries. The Eco-IS is closely linked with the regional and national policies for eco-innovation in Europe, while the ASEI’s impact appears more limited, as of now. In conclusion, the research results give insights into key areas, goals and applications of eco-innovation indices, and can help upgrading eco-innovation indices. This research helps interpret the scores of two indices better and facilitate application of the scores in the multiple ways. It is expected that this research contributes to developing and modifying a global eco-innovation index and enhancing the ability of these indices to facilitate eco-innovation strategies at national levels and across relevant actors

Oxidative polymerization of 1,4-diethynylbenzene into highly conjugated poly(phenylene butadiynylene) within the channels of surface-functionalized mesoporous silica and alumina materials

A polyalkynylene-based conducting polymer (molecular wire) has been synthesized within the Cu-functionalized mesoporous MCM-41 silica catalyst. Fluorescence and 13C solid-state NMR provided spectroscopic evidence that the synthesis of extended polymeric chains with a high degree of alignment requires homogeneously distributed catalytic sites throughout the entire MCM matrix. This type of homogeneity has been achieved via co-condensation of the catalytic groups in narrow pores. In addition, our results indicated that proper adjustment of the pore diameter is vital to prevent clogging of the pores with aggregated or cross-linked polymers or both

A Presumed Etiology of Kawasaki Disease Based on Epidemiological Comparison With Infectious or Immune-Mediated Diseases

Background: Kawasaki disease (KD) may be associated with infection of unknown pathogen(s). For predicting of the etiology of KD, we evaluated epidemiological characteristics in KD, common infectious diseases and immune-mediated diseases in childhood.Methods: We respectively, reviewed the data of patients with KD, influenza, aseptic meningitis, exanthem subitum (ES), Mycoplasma pneumoniae (MP) pneumonia, acute pyelonephritis (APN), Henoch-Schönlein purpura (HSP), acute poststreptococcal glomerulonephritis (APSGN), and childhood asthma. We compared and interpreted epidemiological data across the groups.Results: In age distribution, KD, APN, and ES showed a similar pattern in that majority of patients were infants or young children, and other diseases showed a relatively even age-distribution which had a peak age, mainly 5–6 years, with bell-shape patterns. In annual-case pattern, there were epidemic years in aseptic meningitis and MP pneumonia, and the fluctuated annual cases were seen in other diseases. The trends of decreasing cases were seen in APSGN, HSP, and childhood asthma in recent years. In seasonal frequency, influenza or aseptic meningitis occurred in mainly winter or summer season, respectively. HSP and APSGN cases had less in summer, and KD, APN, and ES showed relatively even occurrence throughout a year without significant seasonal variations.Conclusions: Our results suggest that KD agents may be associated with normal flora that are influenced by environmental changes, since pathogens of APN and ES could be regarded as normal flora that originate from the host itself or ubiquitously existing human reservoirs

Comment on "Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581"

This document is the Accepted Manuscript Version of the following article: Guillem Anglada-Escude and Mikko Tuomi, 'Comment on "Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581"', Science, Vol 347 (6226), 2015, the final, published version is available online at doi: 10.1126/science.1260796. © 2015 The American Association for the Advancement of Science. All rights reserved.Robertson et al. (Reports, 25 July 2014, p. 440) claimed that activity-induced variability is responsible for the Doppler signal of the proposed planet candidate GJ 581d. We point out that their analysis using periodograms of residual data is inappropriate and promotes inadequate tools. Because the claim challenges the viability of the method to detect exo-Earths, we encourage reanalysis and a deliberation on what the field-standard methods should be.Peer reviewedFinal Accepted Versio

Crystal structures of murine norovirus-1 RNA-dependent RNA polymerase in complex with 2-thiouridine or ribavirin

AbstractMurine norovirus-1 (MNV-1) shares many features with human norovirus (HuNoV) and both are classified within the norovirus genus of Caliciviridae family. MNV-1 is used as the surrogate for HuNoV research since it is the only form that can be grown in cell culture. HuNoV and MNV-1 RNA dependent RNA polymerase (RdRp) proteins with the sequence identity of 59% show essentially identical conformations. Here we report the first structural evidence of 2-thiouridine (2TU) or ribavirin binding to MNV-1 RdRp, based on the crystal structures determined at 2.2Å and 2.5Å resolutions, respectively. Cellular and biochemical studies revealed stronger inhibitory effect of 2TU on the replication of MNV-1 in RAW 264.7 cells, compared to that of ribavirin. Our complex structures highlight the key interactions involved in recognition of the nucleoside analogs which block the active site of the viral RNA polymerase