The high-temperature deformation mechanism of the FeCrAl-ODS ferritic steel was investigated at 1000 °C for the creep loading perpendicular to the elongated and aligned grains. The strain rate was ...varied in the range from the order of 10−2 to 10−7s−1. With decreasing strain rate from 10−2 to 10−5s−1, creep mechanism shifts from conventional dislocation creep pinned by oxide particles to grain boundary sliding (GBS) assisted concomitantly by diffusional creep. With further decreasing strain rate to 10−7s−1, deformation mechanism is drastically changed; group of three grains can move cooperatively, and cooperative GBS (CGBS) was originally recognized. The threshold stress for onset of CGBS was designated as σthI(CGBS). Rate limiting process of CGBS is dominated by dislocation movement over the oxide particles so as to relieve the stress accumulation due to CGBS. The σthI(CGBS) for CGBS corresponds to one third of the conventional threshold stress for dislocation creep.
•Creep deformation mechanism was studied for FeCrAl-ODS ferritic steels.•At the strain rate of 10−7s−1, cooperative grain boundary sliding (GCGBS) was discovered.•CGBS is dominated by dislocation movement over the oxide particles.•The threshold stress for CGBS was found to be one third of the conventional threshold stress for dislocation creep.
An abstract of a study by Kamikawa introducing diversity and evolution of non-photosynthetic plastids of Nitzschia spp is presented. Transcriptome analyses and heterologous localization studies ...revealed that, even after loss of photosynthesis, the non-photosynthetic diatom plastids function for biosynthesis of amino acids and fatty acids and for glycolysis and the reductive pentose phosphate pathway, the latter two which share enzymes with the Calvin-Benson cycle without carbon fixation steps.
The high-temperature deformation process of the recrystallized 16CrODS ferritic steel was investigated at 1000°C for the stress loading perpendicular to the elongated grain structure. The strain rate ...was varied in the range from 1.0×10−2 to 1.0×10−5s−1. At the strain rate over 1.0×10−4s−1, deformation is dominated by the conventional dislocation creep. Decreasing strain rate from 1.0×10−4s−1, grain boundary sliding becomes prominent. Accommodation process for the localized stress induced by grain boundary sliding could be dislocation creep at 1.0×10−4s−1, and by diffusional creep at 1.0×10−5s−1 or less. These were verified through the observation of void formation and localized strain accumulation by KAM map.
The dinoflagellates
Alexandrium tamarense (Lebor) Balech and
Alexandrium catenella (Whedon and Kofoid) Balech (Dinophyceae) are believed to be the main species responsible for paralytic shellfish ...poisoning (PSP) all over the world. It is necessary to identify
A. tamarense and
A. catenella cysts and to monitor their distribution in sediment in order to minimize the damages caused by PSP to the economy and food quality because cysts are the seed population for blooms caused by motile vegetative cells. In this study, we developed an efficient DNA extraction method from the natural cysts present in marine sediments after they were size fractionated with a plankton net (mesh size of 20–150
μm). The 10–3000 cysts were added to the sediments collected from the Ariake Sea, and for which the primuline-staining method did not reveal any cysts. DNA was then extracted from each sample, and linear standard curves for
A. tamarense and
A. catenella cysts were obtained from the correlation between the Ct values by real-time PCR and the log of the initial densities of cysts. We monitored the
A. tamarense and
A. catenella cyst densities in the environmental samples. This assay was demonstrated to be a powerful tool for the identification, detection, and quantification of the cysts of the toxic dinoflagellates.
Extensive investigations on apicomplexan mitochondria, such as those of
Plasmodium falciparum, revealed that ribosomal RNAs (rRNAs) are fragmented into multiple short pieces. In this study, we ...isolated three mitochondrial large subunit rRNA (mtLSU rRNA) fragments from the dinoflagellate
Alexandrium catenella. A piece of mtLSU rRNA that possesses high sequence similarity to the
P. falciparum LSU rRNA E fragment was identified in a 1.7-kbp mitochondrial (mt) DNA clone. We further confirmed that the
A. catenella “E-like” fragment is indeed transcriptionally active and that the transcript could form appropriate RNA secondary structures. In addition, we identified expression of two additional rRNA fragments with sequence similarities to
P. falciparum F and G fragments. Notably, the 1.7-kbp mt DNA clone contains only one of the three rRNA fragments identified in this study, suggesting that the rRNA fragments are separately encoded in the
A. catenella mt genome. Given the sister relationship between apicomplexa and dinoflagellates in eukaryote phylogeny, it is most parsimonious to assume that the mt rRNA fragmentation was established prior to the separation of the two protist groups. However, current sequence data on dinoflagellate mitochondria are insufficient to reject the alternative scenario, in which the rRNA fragmentation evolved independently in apicomplexan and dinoflagellate mitochondria.
Aromatic acyl radicals generated from S-(4-cyano)phenyl 2-alkenylthiobenzoate by a nickel complex catalyzed electroreduction undergo 5- and 6-exo cyclization to give 1-indanone and ...dihydro-1-naphthalenone derivatives, respectively.
In the cytochrome
c oxidase subunit I (
cox1) gene of four raphidophycean flagellates
Chattonella antiqua,
C. marina,
C. ovata, and
C. minima we found two group II introns described here as
...Chattonella cox1-i1 and
Chattonella cox1-i2 encoding an open reading frame (ORF) comprised of three domains: reverse transcriptase (RT), RNA maturase (Ma) and zinc finger (H-N-H) endonuclease domains. The secondary structures show both
Chattonella cox1-i1 and
Chattonella cox1-i2 belong to group IIA1, albeit the former possesses a group IIB-like secondary structural character in the
ε′ region of arm I. Our phylogenetic analysis inferred from RT domain sequences of the intronic ORF, comparison of the insertion sites, and the secondary structures of the introns suggests that
Chattonella cox1-i1 likely shares an evolutionary origin with the group II introns inserted in
cox1 genes of five phylogenetically diverged eukaryotes. In contrast,
Chattonella cox1-i2 was suggested to bear a close evolutionary affinity to the group II introns found in diatom
cox1 genes. The RT domain-based phylogeny shows a tree topology in which
Chattonella cox1-i2 is nested in the diatom sequences suggesting that a diatom-to-
Chattonella intron transfer has taken place. Finally, we found no intron in
cox1 genes from deeper-branching raphidophyceans. Based on parsimonious discussion,
Chattonella cox1-i1 and
Chattonella cox1-i2 have invaded into the
cox1 gene of an ancestral
Chattonella cell after diverging from
C. subsalsa.
In this study, nuclear ribosomal RNA gene internal transcribed spacer regions and the cox2–cox1 fragment of the mitochondrial (mt) genome were sequenced in 24 strains of Chattonella spp. Variability ...in both regions showed that the mt genome sequences of Chattonella spp. have a higher evolutionary rate than the nuclear rRNA gene sequences. A maximum likelihood tree based on the mt sequence grouped the Japanese Chattonella strains into two groups (Groups A and B), although no correlation was observed amongst the phylogenetic groups, their morphologies, or the isolated areas. Groups A and B were clearly identified by a polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) assay using FokI, without the need for a sequencing experiment. The PCR‐RFLP assay revealed that Chattonella cells obtained from sea water in Oita, Japan, in 2004 and 2005 belonged to Group B. This is the first report showing the genetic variation in Chattonella spp. using a PCR‐RFLP identification protocol.
The cysts of toxic dinoflagellate Alexandrium tamarense are the seed population for the bloom responsible for paralytic shellfish poisoning (PSP). However, it is impossible to identify the ...Alexandrium spp. cyst on the basis of morphological features. In this study, we prepared A. tamarense cysts by sexual conjugation in laboratory conditions and developed an efficient DNA extraction method for polymerase chain reaction (PCR) assay. Using the A. tamarense cysts, we established the identification and quantification method showing the species specificity and the high sensistivity for A. tamarense cysts using real‐time PCR. This assay was also able to detect and quantify the A. tamarense cysts accurately when mixed with excess cysts of A. catenella (Whedon and Kofoid) Balech prepared by conjugation experiment.
Sweden and Japan represent two different positions regarding policymaking when faced with similar crises of the bank systems. Different institutional settings led the main actors to different paths ...of reactions in order to avoid blame. In the Japanese case, the very close relationship between private banks and the Ministry of Finance, in combination with the lesser degree of widespread perceptions of a system crisis, made it more urgent as well as possible to conceal the actual state of affairs for the politicians. Confronted with the threat of losing power over the financial administration to a new agency, the ministry postponed the reforms in order to conceal the deep financial problems. The institutional setting was different in Sweden. Deregulation had separated the government from the administration of banks. Among the public deteriorating economic conditions were easily connected to the banks. This brought about political unity. It was possible to put the blame on the banks and take the credit for the efforts to tidy up the mess without losing credibility.
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