Creep-strengthening of steel at high temperatures using nano-sized carbonitride dispersions

Creep is a time-dependent mechanism of plastic deformation, which takes place in a range of materials under low stress-that is, under stresses lower than the yield stress. Metals and alloys can be designed to withstand creep at high temperatures, usually by a process called dispersion strengthening, in which fine particles are evenly distributed throughout the matrix. For example, high-temperature creep-resistant ferritic steels achieve optimal creep strength (at 923 K) through the dispersion of yttrium oxide nanoparticles. However, the oxide particles are introduced by complicated mechanical alloying techniques and, as a result, the production of large-scale industrial components is economically unfeasible. Here we report the production of a 9 per cent Cr martensitic steel dispersed with nanometre-scale carbonitride particles using conventional processing techniques. At 923 K, our dispersion-strengthened material exhibits a time-to-rupture that is increased by two orders of magnitude relative to the current strongest creep-resistant steels. This improvement in creep resistance is attributed to a mechanism of boundary pinning by the thermally stable carbonitride precipitates. The material also demonstrates enough fracture toughness. Our results should lead to improved grades of creep-resistant steels and to the economical manufacture of large-scale steel components for high-temperature applications.     

Ascidian sperm chymotrypsin-like enzyme; participation in fertilization

The action of a chymotrypsin-like enzyme from sperm extract from the ascidian Halocynthia roretzi was studied using several substrates. It was found that the most susceptible substrate had the most powerful inhibitory effect on fertilization in this animal. Among the substrates, the order of susceptibility coincided with the order of inhibitory ability, which indicates that the enzyme is involved in the fertilization process.     

Mechanisms for exporting large-sized cargoes from the endoplasmic reticulum

Cargo proteins exported from the endoplasmic reticulum to the Golgi apparatus are typically transported in coat protein complex II (COPII)-coated vesicles of 60–90 nm diameter. Several cargo molecules including collagens and chylomicrons form structures that are too large to be accommodated by these vesicles, but their secretion still requires COPII proteins. Here, we first review recent progress on large cargo secretions derived especially from animal models and human diseases, which indicate the importance of COPII proteins. We then discuss the recent isolation of specialized factors that modulate the process of COPII-dependent cargo formation to facilitate the exit of large-sized cargoes from the endoplasmic reticulum. Based on these findings, we propose a model that describes the importance of the GTPase cycle for secretion of oversized cargoes. Next, we summarize reports that describe the structures of COPII proteins and how these results provide insight into the mechanism of assembly of the large cargo carriers. Finally, we discuss what issues remain to be solved in the future.     

Effects of multiple injections of luteinizing hormone-releasing hormone in the induction of pregnancy in androgenized female rats

Summary A study of the effect of cyclic (every 4 days) administration of gonadotropin releasing hormone on reproductive performance of the androgenized female rat was carried out. The responses measured were indirect indices of increased gonadotropin output; ovulation rate, uterine decidualization, mating and implantation.     

Effect of continuous illumination on secretion of pregnane compounds by the rat ovary

Differences in the secretion of pregnane compounds from rats with follicular polycystic ovaries under constant light and with normal preovulatory ovaries under light-dark conditions were compared. The injection of LH greatly increased the secretion of progesterone. 5 alpha-pregnane-3,20-dione and 3 alpha-hydroxy-5 alpha-pregnan-20-one, in both types of ovaries, but the response of the two progesterone metabolites in the polycystic ovaries was low, suggesting low 5 alpha-reductase activity.     

macho-1 encodes a localized mRNA in ascidian eggs that specifies muscle fate during embryogenesis

Maternal information stored in particular regions of the egg cytoplasm has an important function in the determination of developmental fate during early animal development. Ascidians show mosaic development; such autonomous development has been taken as evidence that prelocalized ooplasmic factors specify tissue precursor cells during embryogenesis. Interest has been concentrated on the mechanisms underlying the formation of muscle cells in the tail, as yellow-coloured myoplasm in eggs is preferentially segregated into muscle-lineage blastomeres. Here we show that maternal messenger RNA of the macho-1 gene is a determinant of muscle fate in the ascidian Halocynthia roretzi. The macho-1 mRNA encodes a zinc-finger protein, and the mRNA is localized to the myoplasm of eggs. Depletion of the mRNA specifically resulted in the loss of primary muscle cells in the tail, as shown by the expression of muscle-specific molecular markers. The myoplasm of macho-1-deficient eggs lost its ability to promote muscle formation. Injection of synthesized macho-1 mRNA caused ectopic muscle formation in non-muscle-lineage cells. Our results indicate that macho-1 maybe both required and sufficient for specification of muscle fate, and that the mRNA is a genuine, localized muscle determinant.     

An urinary metabolite of bromazepam

Zusammenfassung Es wird über Versuche zur Isolierung von Metaboliten im Harn des Kaninchens und des Hundes nach einmaliger oraler Gabe von Bromazepam in hohen Dosen berichtet. Die Ergebnisse der Elementaranalyse und des UV-, IR-, NMR- und Massenspektren deuten darauf, dass es sich um das 3-Hydroxy-Derivat des 2-Amino-5-brombenzolypyridin handelt.

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Acknowledgment. The author is grateful to Dr.M. Fukumoto, Nippon Roche Research Center, Tokyo (Japan) for the gift of broamzepam. Thanks are also due to Prof.M. Hori and Prof.W. Sadée for interpretation of the IR-, NMR-, and mass-spectra.     

Novel metabolite of nitrazepam in the rabbit urine

Summary Two novel metabolites appearing mainly as conjugated form in the urine of rabbits fed nitrazepam have been isolated as deconjugated form. From the data of elemental and spectral analysis, the structure was confirmed as 2-amino-3-hydroxy-5-nitrobenzophenone (M-I) and 2-benzoyl-4-nitro-2-hydroxyacetanilide (M-II).     

Meta-analysis identifies nine new loci associated with rheumatoid arthritis in the Japanese population

Rheumatoid arthritis is a common autoimmune disease characterized by chronic inflammation. We report a meta-analysis of genome-wide association studies (GWAS) in a Japanese population including 4,074 individuals with rheumatoid arthritis (cases) and 16,891 controls, followed by a replication in 5,277 rheumatoid arthritis cases and 21,684 controls. Our study identified nine loci newly associated with rheumatoid arthritis at a threshold of P < 5.0 × 10(-8), including B3GNT2, ANXA3, CSF2, CD83, NFKBIE, ARID5B, PDE2A-ARAP1, PLD4 and PTPN2. ANXA3 was also associated with susceptibility to systemic lupus erythematosus (P = 0.0040), and B3GNT2 and ARID5B were associated with Graves' disease (P = 3.5 × 10(-4) and 2.9 × 10(-4), respectively). We conducted a multi-ancestry comparative analysis with a previous meta-analysis in individuals of European descent (5,539 rheumatoid arthritis cases and 20,169 controls). This provided evidence of shared genetic risks of rheumatoid arthritis between the populations.