Results 1 - 10 of 18643
Results 1 - 10 of 18643. Search took: 0.04 seconds
|Sort by: date | relevance|
[en] A dispersed repetitive Hae III-family sequences in 'Haemanthus katharinae', a monocotyledonous diploid species with very large genome (2C DNA = 117±2.24 pg) were characterized. The restriction pattern is similar in different tissues and organs (root meristems, leaves and endosperm). This Hae III-family is represented by population of highly reiterated fragments whose average sizes were estimated to be: p6 - 167 bp, p7 - 183 bp, p39 - 400 bp and p44 - 501 bp. The above fragments constitute: p6 and p7 together 0.56% (3.26x105 copies), p39 1.62% (8.42x105 copies) and p44 0.28% (4.06x104 copies) of the haploid genome. There is no distinct homology among these fragments. p39 and p44 fragments are characterized by high AT content: 68.0% and 64.3%, respectively, while in p6 it reaches 51.5% and 52.4% in p7. Internal sequence organization in p39 fragment revealed a number of short direct repeats. p44 homologous sequences are located uniformly over the mitotic chromosomes and interphase nuclei. (author). 25 refs, 5 figs
[en] Among feature-rich graphene-related materials, graphene nanoribbon (GNR)-based nanostructures are particularly attractive because they can provide tunable and excellent electronic properties. However, the integration of high-quality GNR-based nanostructures on a large scale is still an open area. In this paper, a novel idea is proposed: transport isolation. By a construction of different orbital hybridizations of the carbon atoms in graphene, the GNR regions and functionalized graphene regions are integrated. In the hybrid system, the functionalized graphene regions play the role of the isolation barrier. Based on the first principle calculation, it is demonstrated that about 0.6 nm wide hydrogenated graphene is enough to reliably isolate the GNR regions. Besides, it is revealed that once the armchair GNRs (AGNRs) are fully isolated by functionalized graphene, their band gaps are basically maintained and are weakly dependent on the width of functionalized graphene regions. In addition, the transport characteristics of those isolated AGNRs are verified to be similar to the pristine AGNRs at the device level. The above virtues infer our method can effectively produce a reliable isolation, verified by a simulation of device integration demo. We hope it can provide an intriguing option for the integration of GNR-based nanostructures. (paper)
[en] This paper outlines a theory of absorption of lower-hybrid (LH) waves in an electron plasma that is based on the nonlinear relation between grad |E3|2, where E3 is the electric field component parallel to the external homogeneous magnetic field, and the space dependent quasi-linear diffusion coefficient, and consequently between grad |E3|2 and the absorption. A local absorption induces an increase of the value of the gradient in the neighbouring region and thereby extends the absorption domain. In this way virtually total 'single-path' absorption of the injected LH power is obtained. The theory also allows an explanation of the density limit in current drive. (author)
[en] Conceptual design of an innovatively small tokamak reactor 'GNOME' based on a non-fission biomass-fusion hybrid concept is proposed. This fusion plant concept intends to use high-temperature heat from the blanket to generate hydrogen or synthetic fuels out of waste biomass. Since energy multiplication is expected by utilizing chemical energy of biomass, the requirement for the fusion plasma for net plant energy output is reduced to Q ≥ 5. As a result, the GNOME reactor has been designed to produce 320 MW fusion power with a 5.2 m major radius, 3.1 normalized beta and 11 T maximum field. This relatively small maximum field can be achieved by using Nb3Sn superconducting magnets. Besides, this reactor allows 3.0 m diameter space for its center solenoid coil and requires 60 MW of the input power. These features require minimal technical extensions from ITER.
[en] Fluorescence in situ hybridization applied to the cytogenetic prenatal diagnosis is a rapid way to stablish a nexus between genes and chromosomes without celular culture and allows detection of chromosomal abnormalities on interphase cells. The aim of the present study was to evaluate this method as a tool in prenatal diagnosis of aneuploidies in high risk pregnancies. Prenatal diagnosis was carried out in 40 high-risk pregnancies using fluorescence in situ hybridization, 34 had successuful results. The 97 % the cases were confirmed by conventional cytogenetic results. The diagnosis of 18, 21 and 13 chromosome aneuploidies showed three hybridization signals in 80 % of the scored nuclei. The results of fluorescence in situ hybridization were in conformity with the results of cytogenetic analysis in all the normal cases (sex and autosomic chromosomes). This technique should be applied in high risk cases of chromosomes aneuploidies (21,18, 13 and X), high maternal anxiety, or when significant clinical situation is present. It should be employed as an adjunctive tool to the examination of fetal chromosomes
The objective of this program is to develop innovative DNA detection technologies to achieve fast microbial community assessment. The specific approaches are (1) to develop inexpensive and reliable sequence-proof hybridization DNA detection technology (2) to develop quantitative DNA hybridization technology for microbial community assessment and (3) to study the microbes which have demonstrated the potential to have nuclear waste bioremediation
[en] The objective of this program is to develop innovative DNA detection technologies to achieve fast microbial community assessment. The specific approaches are (1) to develop inexpensive and reliable sequence-proof hybridization DNA detection technology (2) to develop quantitative DNA hybridization technology for microbial community assessment and (3) to study the microbes which have demonstrated the potential to have nuclear waste bioremediation
[en] The project of ASIPP (with PPPL participation), called FFRF, (R/a=4/1 m/m, Ipl=5 MA, Btor=4-6 T, PDT=50-100 MW, Pfission=80-4000 MW, 1 m thick blanket) is outlined. FFRF stands for the Fusion-Fission Research Facility with a unique fusion mission and a pioneering mission of merging fusion and fission for accumulation of design, experimental, and operational data for future hybrid applications. The design of FFRF will use as much as possible the EAST and ITER design experience. On the other hand, FFRF strongly relies on new, Lithium Wall Fusion plasma regimes, the development of which has already started in the US and China.
[en] Lower Hybrid Waves (LHW) have been successfully used for auxiliary heating and non-inductive current drive in tokamak experiments already for two decades. Experimentally observed characteristics (e.g., the current drive efficiency) have been found to agree well with the theoretical predictions based on the quasilinear theory and a resonant interaction of LHW with electrons. Despite of that, there still remain some open questions, e.g., the disparity between the relatively high phase velocity compared to the velocity of tail electrons for usual plasma temperatures has never been fully explained. Recently, the authors have shown that if the spatial localization of the LHW (lower hybrid cones) is taken into account, the energy density of the wave much exceeds the limit of applicability of the quasilinear theory, and nonlinear effects become significant. It is shown in the present paper that the broadening of resonance observed at high electric field amplitudes is due to the overlap of neighbouring spatial modes. Further, a model of interaction of spatially localized LHW with electrons has been proposed. A good agreement with the usual quasilinear model has been found provided the smoothing of the spectrum due to the overlap of spatial modes is taken into account. The possibility of excitation of Langmuir waves has been demonstrated
[en] Associating a particle accelerator with a nuclear reactor is an idea which is gaining impetus to face several challenges, in particular the management of nuclear wastes. The research carried out throughout the world, in particular at CEA, is especially devoted to the characteristics and performances of 'systems' relying on spallation reactions, according to the various possible uses. (Author)