Design features of the tokamak TEXTOR

TEXTOR is the (T) under bar okamak (E) under bar xperimentfor (T) under bar echnology (O) under bar riented (R) under bar esearch in the field of plasma-wall interaction. The scope includes a detailed analysis of particle and energy exchange between the plasma and the surrounding chamber as well as active measures to optimize the first wall and the plasma boundary region. TEXTOR is a medium-sized tokamak belonging to the class of moderate-field but large-volume devices having a circular cross section of the plasma and an iron core. The plasma major radius is 1.75 m, and the minor radius is 0.47 m. The maximum plasma current is 0.8 MA, the maximum field is 3 T, and the maximum pulse length is 10 s. TEXTOR is fed directly from the 110-kVgrid using an installed converter power of similar to300 MVA. The inner wall of TEXTOR is equipped with several specially shaped limiters being partly remotely movable. Special design features of TEXTOR are excellent access for diagnostics to domains near the wall, large portholes suitable for implementing methods to control the plasma boundary, facilities to heat the vacuum vessel and the liner, and provisions for exchange of the liner. TEXTOR has been upgraded with auxiliary heating systems (neutral beam injection, radio-frequency heating, and microwave heating of 9 MW in total), a toroidal pumped limiter, an upgraded magnetization coil, and recently the dynamic ergodic divertor (DED). The DED is a novel flexible tool to influence transport parameters at the plasma edge and to study the resulting effects on heat exhaust, edge cooling, impurity screening, plasma confinement, and stability. The number of special features and the flexibility of TEXTOR provide excellent opportunities for important contributions to fusion research

The tool steel producer’s contribution to successful die casting of structural components

Die cast structural components for the automotive industry gain more and more importance as theyhighly contribute to a weight reduction of cars and thus to a reduced fuel consumption as well as CO2-emission. So today very often die cast aluminium A-, B- or C-pillar, shock towers, or door componentsreplace traditional steel parts. These structural components are often characterised by large dimensions andcomplicated design. Die casting dies for structural components have to fulfil highest requirements with respectto toughness, high-temperature strength, and thermal fatigue resistance. Often the traditionally used hot-worktool steels like 1.2343 (AISI H 11), 1.2344 (H 13), or 1.2367 cannot fulfil these requirements. Kind & Co.has developed three special hot-work tool steels with significantly improved properties: TQ 1, HP 1, andHTR. The report will not only give a survey on the properties of these steels but also on practical experiencegained with these grades. A proper heat treatment is essential for the performance of the dies. Kind & Co hasrecently set up one of the largest and most modern vacuum hardening furnaces in the world which focuseson these large die casting dies. The report will also show up the contribution of a modern heat treatmentfacility to an economic die casting process of high-class structural components

Seed Embryo Development is Regulated via an AN3-MINI3 Gene Cascade

In agriculture, seed mass is one of the most important components related to seed yield. MINISEED3 (MINI3) which encodes the transcriptional activator WRKY10, is thought to be a pivotal regulator of seed mass. In Arabidopsis SHORT HYPOCOTYL UNDER BLUE1 (SHB1) associates with the promoter of MINI3, regulating embryo cell proliferation (both cell division and elongation), which, in turn, modulates seed mass. Furthermore, the recruitment of SHB1 via MINI3 to both its cognate promoter and that of IKU2 implies a two-step amplification for countering the low expression level of IKU2, which is thought to function as a molecular switch for seed cavity enlargement. However, it is largely unknown how embryo cell proliferation, which encompasses both cell division and elongation, is regulated by SHB1 and MINI3 function. Here, we show that a loss of function mutation within the transcriptional coactivator ANGUSTIFOLIA3 (AN3), increases seed mass. Further, AN3 associates with the MINI3 promoter in vivo. Genetic evidence indicates that the absence of MINI3 function suppresses the decrease of cell number observed in an3-4 mutants by regulating cell division and in turn inhibits increased cell size of the an3-4 line by controlling cell elongation. Thus, seed embryo development is modulated via an AN3-MINI3 gene cascade. This regulatory model provides a deeper understanding of seed mass regulation, which may in turn lead to increased crop yields

Aintegumenta and Aintegumenta-Like6 regulate auxin-mediated flower development in Arabidopsis

<p>Abstract</p> <p>Background</p> <p>Two related genes encoding AP2/ERF-type transcription factors, <it>AINTEGUMENTA </it>(<it>ANT</it>) and <it>AINTEGUMENTA-LIKE6 </it>(<it>AIL6</it>), are important regulators of floral growth and patterning in Arabidopsis. Evidence suggests that these genes promote several aspects of flower development in response to auxin. To investigate the interplay of <it>ANT</it>, <it>AIL6 </it>and auxin during floral development, I have examined the phenotypic consequences of disrupting polar auxin transport in <it>ant</it>, <it>ail6 </it>and <it>ant ail6 </it>mutants by either genetic or chemical means.</p> <p>Results</p> <p>Plants containing mutations in <it>ANT </it>or <it>AIL6 </it>alone or in both genes together exhibit increased sensitivity to disruptions in polar auxin transport. Both genes promote shoot growth, floral meristem initiation and floral meristem patterning in combination with auxin transport. However, differences in the responses of <it>ant </it>and <it>ail6 </it>single mutants to perturbations in auxin transport suggest that these two genes also have non-overlapping activities in each of these developmental processes.</p> <p>Conclusions</p> <p>The enhanced sensitivity of <it>ant </it>and <it>ail6 </it>mutants to alterations in polar auxin transport suggests that these mutants have defects in some aspect of auxin physiology. The inability of <it>ant ail6 </it>double mutants to initiate flowers in backgrounds disrupted for auxin transport confirm the proposed roles for these two genes in floral meristem initiation.</p

DNA Methylation Causes Predominant Maternal Controls of Plant Embryo Growth

The parental conflict hypothesis predicts that the mother inhibits embryo growth counteracting growth enhancement by the father. In plants the DNA methyltransferase MET1 is a central regulator of parentally imprinted genes that affect seed growth. However the relation between the role of MET1 in imprinting and its control of seed size has remained unclear. Here we combine cytological, genetic and statistical analyses to study the effect of MET1 on seed growth. We show that the loss of MET1 during male gametogenesis causes a reduction of seed size, presumably linked to silencing of the paternal allele of growth enhancers in the endosperm, which nurtures the embryo. However, we find no evidence for a similar role of MET1 during female gametogenesis. Rather, the reduction of MET1 dosage in the maternal somatic tissues causes seed size increase. MET1 inhibits seed growth by restricting cell division and elongation in the maternal integuments that surround the seed. Our data demonstrate new controls of seed growth linked to the mode of reproduction typical of flowering plants. We conclude that the regulation of embryo growth by MET1 results from a combination of predominant maternal controls, and that DNA methylation maintained by MET1 does not orchestrate a parental conflict

Characterization and expression profiles of miRNAs in rice seeds

Small RNAs (sRNAs) are common and effective modulators of gene expression in eukaryotic organisms. To characterize the sRNAs expressed during rice seed development, massively parallel signature sequencing (MPSS) was performed, resulting in the obtainment of 797 399 22-nt sequence signatures, of which 111 161 are distinct ones. Analysis on the distributions of sRNAs on chromosomes showed that most sRNAs originate from interspersed repeats that mainly consist of transposable elements, suggesting the major function of sRNAs in rice seeds is transposon silencing. Through integrative analysis, 26 novel miRNAs and 12 miRNA candidates were identified. Further analysis on the expression profiles of the known and novel miRNAs through hybridizing the generated chips revealed that most miRNAs were expressed preferentially in one or two rice tissues. Detailed comparison of the expression patterns of miRNAs and corresponding target genes revealed the negative correlation between them, while few of them are positively correlated. In addition, differential accumulations of miRNAs and corresponding miRNA*s suggest the functions of miRNA*s other than being passenger strands of mature miRNAs, and in regulating the miRNA functions