Oxidation behavior of high-strength FeCrAl alloys in a high-temperature supercritical carbon dioxide environment

The oxidation behavior of three high-strength FeCrAl alloys was investigated in supercritical carbon dioxide environment at 650 ℃. After exposure for 500 h, the weight gains of the FeCrAl alloys gradually decreased with increasing Al content. The oxide scales are primarily composed of α-Al_2O_3 and spinel oxides. With increasing Al content, the amount of α-Al_2O_3 increases and the C content decreased in the oxide scale and sub-scale matrix.Moreover, larger(Nb,Mo)C carbides formed in the sub-scale matrix and their number decreased with the increase of Al content.     

Linking morphology and molecules: integrative taxonomy of spathidiids (Protista: Ciliophora: Litostomatea) from Korea

We isolated seven spathidiids from various terrestrial habitats in Korea: Enchelys megaspinata sp. nov.; Spathidium ascendens Wenzel, 1955; S. papilliferum Kahl, 1930; S. polynucleatum (Foissner et al., 2002) comb. nov.; S. rectitoratum Kahl, 1930; S. securiforme Kahl, 1930 stat. nov.; and Apobryophyllum schmidingeri Foissner and Al-Rasheid, 2007. Their vegetative and resting cyst morphology were studied in vivo and after protargol impregnation. Their phylogenetic relationships were inferred from the analysis of 18S rRNA gene and ITS1-5.8S-ITS2 region sequences. Enchelys megaspinata is nested within the Semispathidium breviarmatum cluster. It differs from all multi-macronucleate congeners either by the number of macronuclear nodules and ciliary rows or by the presence of prominent spines on resting cysts. Both morphological and molecular data support species-level status for S. rectitoratum and S. securiforme. Although S. papilliferum is one of the morphologically most distinct spathidiids due to the presence of oral bulge papillae, it is non-monophyletic. Based on molecular analyses, we suggest reassigning the morphologically transitional S. ascendens and S. polynucleatum, both formerly combined with Epispathidium, to the genus Spathidium. Korean and German populations of Apobryophyllum schmidingeri are highly similar, both morphologically and genetically. The present study highlights the complexity of spathidiid taxonomy, which requires a combination of morphological and molecular approaches to resolve.

www.zoobank.org/urn:lsid:zoobank.org:pub:781F932B-97D1-4B15-9E35-602DC6D3AE67     

eIF2A,an initiator tRNA carrier refractory to eIF2α kinases,functions synergistically with eIF5B

The initiator tRNA (Met-tRNA _i ^Met ) at the P site of the small ribosomal subunit plays an important role in the recognition of an mRNA start codon. In bacteria, the initiator tRNA carrier, IF2, facilitates the positioning of Met-tRNA _i ^Met on the small ribosomal subunit. Eukarya contain the Met-tRNA _i ^Met carrier, eIF2 (unrelated to IF2), whose carrier activity is inhibited under stress conditions by the phosphorylation of its α-subunit by stress-activated eIF2α kinases. The stress-resistant initiator tRNA carrier, eIF2A, was recently uncovered and shown to load Met-tRNA _i ^Met on the 40S ribosomal subunit associated with a stress-resistant mRNA under stress conditions. Here, we report that eIF2A interacts and functionally cooperates with eIF5B (a homolog of IF2), and we describe the functional domains of eIF2A that are required for its binding of Met-tRNA _i ^Met , eIF5B, and a stress-resistant mRNA. The results indicate that the eukaryotic eIF5B–eIF2A complex functionally mimics the bacterial IF2 containing ribosome-, GTP-, and initiator tRNA-binding domains in a single polypeptide.     

Reestablishment of the inactive X chromosome to the ground state through cell fusion-induced reprogramming

The restricted gene expression pattern of a differentiated cell can be reversed by fusion of the somatic cell with a more developmentally potent cell type, such as an embryonic stem (ES) cell. During this reprogramming process, somatic cells obtain most of the characteristics of pluripotent cells. Reactivation of an inactive X chromosome (Xi) is an important epigenetic marker confirming the pluripotent reprogramming of somatic cells. Female somatic cells contain one active X chromosome (Xa) and one Xi, and following the fusion of these cells with male ES cells, the Xi becomes activated, resulting in XaXaXaY fusion hybrid cells. To monitor Xi reactivation, transgenic female neural stem cells (fNSCs) carrying a green fluorescent protein (GFP) reporter gene expressed on the Xa (X-GFP), but not on the Xi, were used for reprogramming. XaXi^GFP NSCs, whose GFP reporter was silenced, were fused with HM1 ES cells (XY) to induce pluripotent reprogramming. The Xi^GFP of NSCs were found to be activated on day 4 post-fusion, indicating reactivation of the Xi. Hybrid cells showed pluripotent cell-specific characteristics cells including inactivation of the NSC marker Nestin, DNA demethylation of Oct4, DNA methylation of Nestin, and reactivation of the Xi. Following differentiation of the (GFP-positive) hybrid cells through embryoid body formation, the proportion of GFP-negative cells was found to be approximately 26?%, indicating that there was random inactivation of one of the three Xas. Here, we showed that the Xi of somatic cells is reprogrammed to the Xa state and that cellular differentiation occurs randomly, i.e., regardless of the Xa or Xi state, indicating that the memory of the Xi of somatic cells has been erased and reset to the ground state (i.e., inner cell mass-like state), indicating that random X-chromosome inactivation occurs upon differentiation.     

A spatial entropy reflecting distribution of spatial objects

Decision trees are mainly used to classify data and predict data classes. A spatial decision tree has been designed using Euclidean distance between objects for reflecting spatial data characteristic. Even though this method explains the distance of objects in spatial dimension, it fails to represent distributions of spatial data and their relationships. But distributions of spatial data and relationships with their neighborhoods are very important in real world. This paper proposes decision tree based on spatial entropy that represents distributions of spatial data with dispersion and dissimilarity. The rate of dispersion by dissimilarity presents how related distribution of spatial data and nonspatial attributes. The experiment evaluates the accuracy and building time of decision tree as compared to previous methods and it shows that the proposed method makes efficient and scalable classification for spatial decision support.     

On-line Cutting Quality Recognition in Milling Using a Radical Basis Function Neural Network

Tool wear, chatter vibration, chip breaking and built-up edge are main phenomena to be monitored in modern manufacturing processes, which are considered as important factors to the quality of products.They are closely related to the cutting parameters, which are to be selected in manufacturing process.However, it is very difficult to measure directly the cutting quality based on on-line monitoring.In this study, the relationship between the cutting parameters and cutting quality is analyzed.A Radical Basis Function (RBF) neural network based on-line quality recognition scheme is also presented, which monitors the level of surface roughness.The experimental results reveal that the RBF neural network has a high prediction success rate.     

A study of the suppression of the high-temperature helium embrittlement in an oxide-particle dispersion strengthened alloy

In this paper, an investigation on the micro-structure of an Fe-base oxide-dispersion-strengthened （ODS） alloy irradiated with high-energy ^20Ne ions to different doses at a temperature around 0.5Tin （Tin is the melting point of the alloy） is presented. Investigation with the transmission electron microscopy found that the accelerated growth of voids at grain-boundaries, which is usually a concern in conven- tional Fe-base alloys under conditions of inert-gas implantation, was not observed in the ODS alloy irradiated even to the highest dose （12000 at.ppm Ne）. The reason is ascribed to the enhanced recombination of point defects and strong trapping of Ne atoms at the interfaces of the nano-scale oxide particles in grains. The study showed that ODS alloys have good resistance to the high-temperature inter-granular embrittlement due to inert-gas accumulation, exhibiting prominence of application in harsh situations of considerable helium production at elevated temperatures like in a fusion reactor.