Nuclear reaction

When boron carbide is used as a neutron absorber in nuclear power plants, large quantities of helium are produced. To simulate the gas behaviour, helium implantations were carried out in boron carbide. The samples were then annealed up to 1500 °C in order to observe the influence of temperature and duration of annealing.

8p christabelhuynh 31-05-2020 14 2   Download

This study aims at better understanding the chemical and physico-chemical phenomena of uranium dioxide dissolution reactions in nitric acid media in the Purex process, which separates the reusable materials and the final wastes of the spent nuclear fuels.

13p christabelhuynh 29-05-2020 13 1   Download

Key reactions have been selected to compare JEFF-3.3 (CIELO 2) and IAEA CIELO (CIELO 1) evaluated nuclear data files for neutron induced reactions on 235U and 238U targets. IAEA CIELO evaluation uses reaction models to construct the evaluation prior, but strongly relied on differential data including all reaction cross sections fitted within the IAEA Neutron Standards project.

5p christabelhuynh 29-05-2020 11 0   Download

It is also well known that the knowledge of nuclear reaction mechanisms is at best approximate, and that their modeling relies on many parameters which do not have a precise physical meaning outside of their specific implementations in nuclear model codes: they carry both specific physical information, and effective information that is related to the deficiencies of the model itself.

8p christabelhuynh 29-05-2020 8 1   Download

N-Heterocyclic carbenes are widely used in organic reactions and coordination chemistry. In the present study, 2,3-dihydro-1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (1) is reacted with diphenyl disulfide, methyl phenyl disulfide, and bis(methylsulfonyl)methane to yield target compounds 5, 6, and 7 respectively.

6p tocectocec 25-05-2020 8 0   Download

This dissertation is constructed by an overview, three chapters and the conclusion; the general knowledge of nuclear physics, astrophysics and the goals of this work are mentioned in the first chapter; the basic theory of the stellar reaction rate and the matrix method used to determine reaction rate is also mentioned in this part.

153p fujijudo87 07-07-2014 73 10   Download

The two group I introns Nae.L1926 and Nmo.L2563, found at two different sites in nuclear LSU rRNA genes of Naegleria amoebo-flagellates, have been characterized in vitro. Their structural organization is related to that of the mobile Physarum intron Ppo.L1925 (PpLSU3) with ORFs extending the L1-loop of a typical group IC1 ribozyme. Nae.L1926, Nmo.L2563 and Ppo.L1925 RNAs all selfsplice in vitro, generating ligated exons and full-length intron circles as well as internal processed excised intron RNAs....

9p system191 01-06-2013 28 5   Download

Many biological C-H activation reactions exhibit nonclassical kinetic isotope effects (KIEs). These nonclassical KIEs are too large (kH/kD 7) and/or exhibit unusual temperature dependence such that the Arrhenius prefactor KIEs (AH/AD) fall outside of the semiclassical range near unity. The focus of this minireview is to discuss such KIEs within the context of the environmentally coupled hydrogen tunneling model.

9p system191 01-06-2013 38 4   Download

Human immunodeficiency virus type 1 protein R (HIV-1 Vpr) promotes nuclear entry of viral nucleic acids in nondividing cells, causes G2 cell cycle arrest and is involved in cellular differentiation and cell death. Vpr subcellular localization is as variable as its functions. It is known, that consistent with its role in nuclear transport, Vpr localizes to the nuclear envelope of human cells. Further, a reported ion channel activity of Vpr is clearly dependent on its localization in or at membranes.

6p system191 01-06-2013 37 4   Download

Emerin is a ubiquitously expressed inner nuclear membrane protein of unknown function. Mutations in its gene give rise to X-linked Emery–Drei-fuss muscular dystrophy (X-EDMD), a neuromuscular condition with an associated life-threatening cardiomyopathy. We have previously reported that emerin is phosphorylated in a cell cycle-dependent manner in human lymphoblastoid cell lines [Ellis et al. (1998) Aberrant intracellular targeting and cell cycle-dependent phosphorylation of emerin contribute to the EDMD phenotype.J. Cell Sci. 111, 781–792]. ...

14p research12 29-04-2013 41 4   Download

The osmoregulated periplasmic glucans (OPGs) produced byRhodobacter sphaeroides, a free-living organism, were isolated by trichloracetic acid treatment and gel permeation chromatography. Compounds obtained were characterized by compositional analysis, matrix-assisted laser desorption ionization mass spectrometry and nuclear magnetic resonance.R. sphaeroidespredominantly synthesizes acyclic glucan containing 18 glucose residues that canbe substituted by one to seven succinyl esters residues at the C6position of some of the glucose residues, and by one or two acetyl resi-dues....

9p research12 29-04-2013 38 1   Download

The invertebrate nuclear receptor, ultraspiracle (USP), an ortholog of the vertebrate RXR, is typically modelled as an orphan receptor that functions without a ligand-binding activity. The identification of a ligand that can transcrip-tionally activate USP would provide heuristic leads to the structure of potentially high affinity activating compounds, with which to detect unknown regulatory pathways in which this nuclear receptor participates.

11p tumor12 22-04-2013 39 2   Download

A histone heterodimer, designated as p28, which contains an N e (c-glutamyl)lysine cross-link between Gln9 of histone H2B and Lys5 or Lys12 of histone H4, is present in starfish (Asterina pectinifera) sperm. Treatment of spermnuclei with micrococcal nuclease produced soluble chromatin, which was size-fractionated by sucrose-gradient centrifugation to give p28-containing oligonucleosome and p28-free mono-nucleosome fractions, indicating that the cross-link is inter-nucleosomal.

10p tumor12 20-04-2013 39 4   Download

GToligomers, showingadose-dependent cytotoxic effect on a variety of human cancer cell lines, but not on normal human lymphocytes, recognize and form complexes with nuclear proteins.By working with human T-lymphoblastic CCRF-CEM cells and by using MS and SouthWestern blotting, we identified eukaryotic elongation factor 1 alpha (eEF1A) as the main nuclear protein that specifically recognizes these oligonucleotides.Western blotting and supershift assays confirmed the nature of this protein and its involvement in forming a cytotoxicity-related complex (CRC)....

12p tumor12 20-04-2013 34 1   Download

Increasing evidence suggests that melatonin can exert some effect at nuclear level. Previous experiments using binding techniques clearly showed the existence of specificmelatonin binding sites in cell nucleus of rat liver. To further identify these sites, nuclear extracts fromrathepatocyteswere treated withdifferent percentages of ammoniumsulfate andpurified by affinity chromatography. Subsequent ligandblot analysis shows the presence of two polypeptides of
60 and
74 kDa that bind specifically to melatonin. ...

9p tumor12 20-04-2013 57 2   Download

A novel ATP-dependent nuclear DNA unwinding enzyme from pea has been purified to apparent homogeneity and characterized. This enzyme is present at extremely low abundance and has the highest specific activity among plant helicases. It is a heterodimer of 54 and 66 kDa polypeptides as determined by SDS/PAGE. On gel filtration chroma-tography and glycerol gradient centrifugation it gives a native molecular mass of 120 kDa and is named as pea DNA helicase 120 (PDH120).

11p fptmusic 16-04-2013 39 3   Download

Several transcription factors with the function of setting the biological clock in vertebrates have been described. A detailed understanding of their nucleocytolasmic transport properties may uncover novel aspects of the regulation of the circadian rhythm. This assumption led us to perform a systematic analysis of the nuclear import characteristics of the different murine PER and CRY proteins, usingXenopusoocytes and HeLa cells as experimental systems.

11p fptmusic 11-04-2013 26 2   Download

In a previous study we showed that natural polyamines interact in the nuclear environment with phosphate groups to form molecular aggregates [nuclear aggregates of polyamines (NAPs)] with estimated molecular mass values of 8000, 4800 and 1000 Da. NAPs were found to interact with genomic DNA, influence its conformation and interfere with the action of nucleases.

11p fptmusic 11-04-2013 43 2   Download

Analysis of a draft nuclear genome sequence of the diatomThalassiosira pseudonana revealed the presence of 11 open reading frames showing significant similarity to functionally characterized fatty acid front-end desaturases. The corresponding genes occupy discrete chromosomal loca-tions as determined by comparison with the recently published genome sequence. Phylogenetic analysis showed that two of the T. pseudonana desaturase (Tpdes) sequences grouped with proteobacterial desaturases that lack a fused cytochrome b5 domain. ...

12p fptmusic 11-04-2013 32 2   Download

Analyses of integration of two-hormone signaling through the vertebrate nuclear hormone receptors, for which the retinoid X receptor is one part-ner, have generated a number of mechanistic models, including those des-cribed as ‘subordination’ models wherein ligand-activation of one partner is subordinate to the liganded state of the other partner.

13p awards 06-04-2013 17 3   Download