The effect of Ln(III)/An(III) separation on TRU multi-recycling in CONFU assembly

This work examines the basic feasibility of the net-zero-balance TRU multi-recycling concept in which trivalent lanthanide fission products (Ln(III) ) are not separated from trivalent actinides (An(III)). The TRU together with Eu and Gd isotopes are recycled in a standard PWR using Combined Non-Fertile and UO2 (CONFU) assembly design. The assembly assumes a heterogeneous structure where about 20% of U02 fuel pins on the assembly periphery are replaced with Inert Matrix Fuel (IMF) pins hosting TRU, Gd, and Eu generated in the previous cycles. The 2-D neutronic analysis show potential feasibility of Ln / An recycling in PWR using CONFU assembly. Recycling of Ln reduces the fuel cycle length by about 30 effective full power days (EFPD) and TRU destruction efficiency by about 5%. Power peaking factors and reactivity feedback coefficients are close to those of CONFU assembly without Ln recycling.

A combined nonfertile and UO2 PWR fuel assembly for actinide waste minimization

A new combined Non Fertile and Uranium (CONFU) fuel assembly is proposed to limit the actinides that need long-term high-level waste storage from the pressurized water reactor (PWR) fuel cycle. In the CONFU assembly concept, ∼20% of the UO2 fuel pins are replaced with fertile free fuel hosting the transuranic elements (TRUs) generated in the previous cycle. This leads to a fuel cycle sustainable with respect to net TRU generation, and the amount and radiotoxicity of the nuclear waste can be significantly reduced in comparison with the conventional once-through UO2 fuel cycle. It is shown that under the constraints of acceptable power peaking limits, the CONFU assembly exhibits negative reactivity feedback coefficients comparable in values to those of the reference UO2 fuel. Feasibility of the PWR core operation and control with complete TRU recycle has been shown based on full-core three-dimensional neutronic simulation. However, gradual buildup of small amounts of Cm and Cf challenges fuel reprocessing and fabrication due to the high spontaneous fission rates of these nuclides and heat generation by some Pu, Am, and Cm isotopes. Feasibility of the processing steps becomes more attainable if the time between discharge and reprocessing is 20 yr or longer.

Cytological Mechanism on the Integration of Heterologous Genome or Chromosomes in the Unique Gynogenetic Carassius auratus gibelio

银鲫（ＣａｒａｓｉｕｓａｕｒａｔｕｓｇｉｂｅｌｉｏＢｌｏｃｈ）是行天然雌核发育生殖的两性型三倍体鱼类，与普通两性融合生殖鱼类相比，具有独特的育种优势。八十年代以来，异育银鲫、复合四倍体异育银鲫的发现表明，雌核发育卵子不但具有保持自身全部染色体的能力，还能整合异源精子的部分遗传物质或整个基因组，影响雌核发育后代的性状。因此，搞清楚异源基因组的整合机制对于进一步弄清其发育模式以及诱导复合多倍体银鲫均具有十分重要的作用。两性融合发育鱼类的精子入卵后，精核在促精核活化因子的诱导下，可以逐渐解凝并形成雄性原核；而在

Chemical nano-gardens: growth of salt nanowires from supramolecular self-assembly gels.

In this article, we examine the phenomenon of single-crystal halide salt wire growth at the surface of porous materials. We report the use of a single-step casting technique with a supramolecular self-assembly gel matrix that upon drying leads to the growth of single-crystal halide (e.g., NaCl, KCl, and KI) nanowires with diameters ~130-200 nm. We demonstrate their formation using electron microscopy and electron-dispersive X-ray spectroscopy, showing that the supramolecular gel stabilizes the growth of these wires by facilitating a diffusion-driven base growth mechanism. Critically, we show that standard non-supramolecular gels are unable to facilitate nanowire growth. We further show that these nanowires can be grown by seeding, forming nanocrystal gardens. This study helps understand the possible prefunctionalization of membranes to stimulate ion-specific filters or salt efflorescence suppressors, while also providing a novel route to nanomaterial growth.

Europium-directed self-assembly of a luminescent supramolecular gel from a tripodal terpyridine-based ligand.

Eu(III), the last piece in the puzzle: Europium-induced self-assembly of ligands having a C(3)-symmetrical benzene-1,3,5-tricarboxamide core results in the formation of luminescent gels. Supramolecular polymers are formed through hydrogen bonding between the ligands. The polymers are then brought together into the gel assembly through the coordination of terpyridine ends by Eu(III) ions (blue dashed arrow: distance between two ligands in the strand direction).

Genome-wide identification and characterization of cytochrome P450 monooxygenase genes in the ciliate Tetrahymena thermophila

Background: Cytochrome P450 monooxygenases play key roles in the metabolism of a wide variety of substrates and they are closely associated with endocellular physiological processes or detoxification metabolism under environmental exposure. To date, however, none has been systematically characterized in the phylum Ciliophora. T. thermophila possess many advantages as a eukaryotic model organism and it exhibits rapid and sensitive responses to xenobiotics, making it an ideal model system to study the evolutionary and functional diversity of the P450 monooxygenase gene family. Results: A total of 44 putative functional cytochrome P450 genes were identified and could be classified into 13 families and 21 sub-families according to standard nomenclature. The characteristics of both the conserved intron-exon organization and scaffold localization of tandem repeats within each P450 family clade suggested that the enlargement of T. thermophila P450 families probably resulted from recent separate small duplication events. Gene expression patterns of all T. thermophila P450s during three important cell physiological stages (vegetative growth, starvation and conjugation) were analyzed based on EST and microarray data, and three main categories of expression patterns were postulated. Evolutionary analysis including codon usage preference, sit-especific selection and gene-expression evolution patterns were investigated and the results indicated remarkable divergences among the T. thermophila P450 genes. Conclusion: The characterization, expression and evolutionary analysis of T. thermophila P450 monooxygenase genes in the current study provides useful information for understanding the characteristics and diversities of the P450 genes in the Ciliophora, and provides the baseline for functional analyses of individual P450 isoforms in this model ciliate species.

Isolation, characterization and genome sequence of a birnavirus strain from flounder Paralichthys olivaceus in China

A birnavirus strain, Paralichthys olivaceus birnavirus (POBV), was isolated and characterized from cultured flounder in China, and its complete genomic sequence was subsequently determined. The virus could induce cytopathic effects (CPE) in four of seven fish cell lines and was resistant to chloroform, 5-iodo-2'-deoxyuridine, acid and alkaline pH, and heat treatment. Purified virus particles had a typical icosahedral shape, with a diameter of approximately 55-60 nm. The genomic segments A and B of POBV were 3,091 and 2,780 bp in length and shared many of the features of the members of the family Birnaviridae. Segment A contained two partially overlapping ORFs encoding a polyprotein, pVP2-VP4-VP3, and a nonstructural protein, VP5, while segment B had only one ORF encoding for the VP1, a viral RNA-dependent RNA polymerase (RdRp). This is the first report about a birnavirus strain from a new non-salmonid host in China and its complete genome sequence.

Characterization of complete genome sequence of the spring viremia of carp virus isolated from common carp (Cyprinus carpio) in China

The complete genome of spring viraemia of carp virus (SVCV) strain A-1 isolated from cultured common carp (Cyprinus carpio) in China was sequenced and characterized. Reverse transcription-polymerase chain reaction (RT-PCR) derived clones were constructed and the DNA was sequenced. It showed that the entire genome of SVCV A-1 consists of 11,100 nucleotide base pairs, the predicted size of the viral RNA of rhabdoviruses. However, the additional insertions in bp 4633-4676 and bp 4684-4724 of SVCV A-1 were different from the other two published SVCV complete genomes. Five open reading frames (ORFs) of SVCV A-1 were identified and further confirmed by RT-PCR and DNA sequencing of their respective RT-PCR products. The 5 structural proteins encoded by the viral RNA were ordered 3'-N-P-M-G-L-5'. This is the first report of a complete genome sequence of SVCV isolated from cultured carp in China. Phylogenetic analysis indicates that SVCV A-1 is closely related to the members of the genus Vesiculovirus, family Rhabdoviridae.

The complete mitochondrial genome of the Chinese hook snout carp Opsariichthys bidens (Actinopterygii : Cyprinifonnes) and an altemative pattem of mitogenomic evolution in vertebrate

The complete mitochondrial genome sequence of the Chinese hook snout carp, Opsariichthys bidens, was newly determined using the long and accurate polymerase chain reaction method. The 16,611-nucleotide mitogenome contains 13 protein-coding genes, two rRNA genes (12S, 16S) 22 tRNA genes, and a noncoding control region. We use these data and homologous sequence data from multiple other ostariophysan fishes in a phylogenetic evaluation to test hypothesis pertaining to codon usage pattern of O. bidens mitochondrial protein genes as well as to re-examine the ostariophysan phylogeny. The mitochondrial genome of O. bidens reveals an alternative pattern of vertebrate mitochondrial evolution. For the mitochondrial protein genes of O. bidens, the most frequently used codon generally ends with either A or C, with C preferred over A for most fourfold degenerate codon families; the relative synonymous codon usage of G-ending codons is greatly elevated in all categories. The codon usage pattern of O. bidens mitochondrial protein genes is remarkably different from the general pattern found previously in the relatively closely 9 related zebrafish and most other vertebrate mitochondria. Nucleotide bias at third codon positions is the main cause of codon bias in the mitochondrial protein genes of O. bidens, as it is biased particularly in favor of C over A. Bayesian analysis of 12 concatenated mitochondrial protein sequences for O. bidens and 46 other teleostean taxa supports the monophyly of Cypriniformes and Otophysi and results in a robust estimate of the otophysan phylogeny. (C) 2007 Published by Elsevier B.V.

Identification of genome organization in the unusual allotetraploid form of Carassius auratus gibelio

The unusual allotetraploid form with unequal contribution of chromosome sets was discovered from the gynogenetic offspring of Carassius auratus gibelio stimulated by red common carp sperm. In this study, genomic in situ hybridization (GISH) and fluorescent in situ hybridization (FISH) with 45S rDNA probe are used. The GISH results lead to the identification of species-specific chromosomes, which permits to demonstrate the origin and genome organization in the allotetraploid form. Moreover, chromosome localization of 45S rDNA and co-localizations of 45S rDNA and Cyprinus carpio genomic DNA further confirm that one extra 45S rDNA positive chromosome in the allotetraploid form originates from the paternal haploid genome of C carpio, and other 5 45S rDNA-containing chromosomes are from the maternal genome of Carassius auratus gibelio. And, the correlation between 45 rDNA and the nucleolar organizer regions (NORs) is confirmed by silver nitrate staining. The data provide direct experiment evidence that the allotetraploid actually contains three chromosome sets of Carassius auratus gibelio and one chromosome set of C carpio, and will be a useful genetic material for both basic research and breeding practice. (c) 2006 Elsevier B.V. All rights reserved.