Abstract
X-ray absorption spectroscopy was applied to understand the speciation of elements relevant to the immobilisation and disposal of radioactive plutonium bearing wastes, utilizing Ce as a Pu ...surrogate. Ce L
3
XANES (X-ray Absorption Near Edge Structure) characterisation of a crystallised glass material produced by cold crucible plasma vitrification, at demonstration scale, evidenced incorporation as Ce
3+
within the glass phase, providing an important validation of laboratory scale studies. U and Ce L
3
XANES investigation of brannerite ceramics, U
0.9
Ce
0.1
Ti
2
O
6
, synthesized under oxidizing, neutral and reducing conditions, established the charge compensation mechanism as incorporation of Ce
3+
through formation of U
5+
and/or U
6+
In each of these examples, X-ray Absorption Spectroscopy has provided a pivotal understanding of element speciation in relation to the mechanism of incorporation within the host wasteform intended for geological disposal.
The ability to predict or confirm ferroresonance depends primarily on the correctness of the transformer model used by the computer simulation. Ferroresonance is introduced and a general modeling ...approach is given. An overview of available literature and contributors to this area is provided. A simple case of ferroresonance in a single phase transformer is used to illustrate this 'phenomenon'. Three phase transformer core structures are discussed. Ferroresonance in three phase grounded-wye distribution systems is described and illustrated with waveform data obtained from laboratory simulations. Representation of the study zone is discussed, modeling techniques are presented, and implementation suggestions are made. Three case studies are presented. Transformer representation is critical to performing a valid simulation. The direction of ongoing research is discussed, and the reader is advised to monitor the literature for ongoing rapid improvements in transformer modeling techniques.
Little is known about the physical makeup of heterochromatin in the soybean (Glycine max L. Merr.) genome. Using DNA sequencing and molecular cytogenetics, an initial analysis of the repetitive ...fraction of the soybean genome is presented. BAC 076J21, derived from linkage group L, has sequences conserved in the pericentromeric heterochromatin of all 20 chromosomes. FISH analysis of this BAC and three subclones on pachytene chromosomes revealed relatively strict partitioning of the heterochromatic and euchromatic regions. Sequence analysis showed that this BAC consists primarily of repetitive sequences such as a 102-bp tandem repeat with sequence identity to a previously characterized approximately 120-bp repeat (STR120). Fragments of Calypso-like retroelements, a recently inserted SIRE1 element, and a SIRE1 solo LTR were present within this BAC. Some of these sequences are methylated and are not conserved outside of G. max and G. soja, a close relative of soybean, except for STR102, which hybridized to a restriction fragment from G. latifolia. These data present a picture of the repetitive fraction of the soybean genome that is highly concentrated in the pericentromeric regions, consisting of rapidly evolving tandem repeats with interspersed retroelements.
Eighty six subtalar arthrodeses performed between 1985 and 1996 for complications associated with intra-articular calcaneal fractures were retrospectively evaluated. Patients were divided into three ...Groups: (I) 59 patients with calcaneal malunions (II) 13 patients with failed open reduction and internal fixation, and (III) eight patients undergoing open reductions and primary fusion for highly comminuted fractures. In each scenario, internal fixation was achieved with cancellous lag screws. Bone graft material consisted of either autogenous iliac crest graft, local graft obtained from the lateral wall exostectomy of the malunion, or freeze-dried cancellous allograft. Fusions in Groups II and III were performed in situ. Fusions in Group I were performed either in situ or utilizing a variety of reconstructive procedures depending upon the type of malunion encountered. Eighty three of the 86 fusion attempts were successful following the initial operations for a union rate of 96%. Fusion rates were similar regardless of the graft material used. Complications included four varus malunions, four cases of osteomyelitis, and two cases of reflex sympathetic dystrophy. A statistically significant shorter hospital stay was found for patients not undergoing iliac crest bone graft procedures. Eighty patients with at least two year follow up achieved a mean American Orthopaedic Foot and Ankle Society(AOFAS) ankle-hindfoot score of 75.0. Scores were similar for all three groups and for the various types of reconstructive procedures used. No correlation was found between postoperative talar declination angle and the AOFAS ankle-hindfoot score. Worker's compensation patients tended to have a poorer clinical outcome.
The development of fluorescence in situ hybridization (FISH) has led to the advancement of chromosome studies not only for physical mapping and genome analyses but also as a tool for evolutionary ...studies. Isolated repetitive DNA sequences have been useful cytological markers, but large-insert genomic libraries (e.g., bacterial artificial chromosomes BACs, yeast artificial chromosomes YACs, and cosmids) are being increasingly used to serve as probes for large segments of DNA across related genomes. Although FISH is usually applied to metaphase chromosomes, fiber FISH, a variation of FISH using extended DNA fibers, is now used to measure loci at the resolution of a few kilobases to compare orthologous genome segments across related genomes. A generalized set of protocols for chromosome preparation, FISH, and fiber FISH are presented; however, it is often necessary to experiment with techniques for different plant taxa for successful molecular cytogenetic studies.
The ability to predict or confirm ferroresonance depends primarily on the correctness of the transformer model used by the computer simulation. Ferroresonance is introduced and a general modeling ...approach is given. An overview of available literature and contributors to this area is provided. A simple ease of ferroresonance in a single phase transformer is used to illustrate this "phenomenon". Three phase transformer core structures are discussed. Ferroresonance in three phase grounded-wye distribution systems is described and illustrated with waveform data obtained from laboratory simulations. Representation of the study zone is discussed, modeling techniques are presented, and implementation suggestions are made. Three case studies are presented. Transformer representation is critical to performing a valid simulation. The direction of ongoing research is discussed, and the reader is advised to monitor the literature for ongoing rapid improvements in transformer modeling techniques.
Soybean (Glycine max L. Merr.) is presumed to be an ancient polyploid based on chromosome number and multiple RFLP fragments in genetic mapping. Direct cytogenetic observation of duplicated regions ...within the soybean genome has not heretofore been reported. Employing flourescence in situ hybridization (FISH) of genetically anchored bacterial artificial chromosomes (BACs) in soybean, we were able to observe that the distal ends of molecular linkage group E had duplicated regions on linkage groups A2 and B2. Further, using fiber-FISH, it was possible to measure the molecular size and organization of one of the duplicated regions. As FISH did not require repetitive DNA for blocking fluorescence signals, we assume that the 200-kb genome region is relatively low in repetitive sequences. This observation, along with the observation that the BACs are located in distal euchromatin regions, has implications for genome structure/evolution and the approach used to sequence the soybean genome.
Vast areas of Europe were contaminated by the fallout of
Cs and other radionuclides, as a result of the Chernobyl accident in 1986. The post-fallout redistribution of Chernobyl-derived
Cs was ...associated with erosion and sediment transport processes within the fluvial system. Bottom sediments from lakes and reservoirs can provide a valuable source of information regarding the post-fallout redistribution and fate of
Cs released by the Chernobyl accident. A detailed investigation of sediment-associated
Cs in the bottom sediments of a reservoir in a Chernobyl-affected area in Central Russia has been undertaken. A new approach, based on the vertical distribution of
Cs activity concentrations in the reservoir bottom sediment makes it possible to separate the initially deposited bottom sediment, where the
Cs activity reflects the direct fallout of Chernobyl-derived
Cs to the reservoir surface and its subsequent incorporation into sediment deposited immediately after the accident, from the sediment mobilized from the catchment deposited subsequently. The deposits representing direct fallout from the atmosphere was termed the "Chernobyl peak". Its shape can be described by a diffusion equation and it can be distinguished from the remaining catchment-derived
Cs associated with sediment accumulated with sediments during the post-Chernobyl period. The
Cs depth distribution above the "Chernobyl peak" was used to provide a record of changes in the concentration of sediment-associated
Cs transported from the upstream catchment during the post-Chernobyl period. It was found that the
Cs activity concentration in the sediment deposited in the reservoir progressively decreased during the 30-year period after the accident due to a reduction in the contribution of sediment eroded from the arable land in the catchment. This reflects a reduction in both the area of cultivated land area and the reduced incidence of surface runoff from the slopes during spring snowmelt due to climate warming.
The anti-carcinogenic effects of broccoli have been attributed to sulforaphane, the hydrolysis product of glucoraphanin (GRP). Here we determined if purified GRP, in the absence of the plant-derived ...hydrolyzing enzyme myrosinase, could affect pulmonary and hepatic ethoxyresorufin
O-deethylase (EROD) and/or NAD(P)H-quinone oxidoreductase 1 (NQO1) activity. Male F344 rats were administered semi-synthetic, semi-purified or purified GRP (240
mg/kg: 550
μmol/kg rat daily for 4 days) by gavage. Hepatic and pulmonary NQO1 activity increased (∼20%), but not EROD. Varying doses of semi-purified GRP (30, 60, or 120
mg/kg rat daily for 4 days) again caused no change in EROD activity, although a dose-dependent increase in NQO1 was seen. Urinary excretion of mercapturic acids showed no difference between preparations, and recovery increased with decreasing dose. Histopathologic examination revealed no abnormal tissues other than cecum, where inflammation was dose dependent; mild at 120
mg/kg and severe at 240
mg/kg, a greatly supra-physiological dose. We conclude that GRP 30–60
mg/kg p.o. is safe and effectively enhances NQO1 in all tissues evaluated.
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