MEASUREMENT OF OPERATIONAL QUANTITIES Hp(0.07) AND Hp(3) FOR INDIGENOUSLY DEVELOPED 106Ru/106Rh SOURCE USING AN EXTRAPOLATION CHAMBER.

In the present study, a prototype 106Ru/106Rh source was fabricated using high level liquid waste from reactor fuel, fixed in a stainless steel housing with a window and backing made of silver. The study involves measurement of the operational quantities Hp(0.07), Hp(3) and the percentage depth dose (PDD) using an extrapolation chamber. It also involves determination of necessary correction factors to arrive at Hp(0.07) and Hp(3) following International Organisation for Standardisation (ISO) and methods suggested in literature. The study facilitates incorporation of the 106Ru/106Rh source as a beta reference source for quality assurance programme in TLD personnel monitoring as per the guidelines of ISO.

Unique reversibility in extraction mechanism of U compared to solvent extraction for sorption of U(VI) and Pu(IV) by a novel solvent impregnated resin containing trialkyl phosphine oxide functionalized ionic liquid.

Novel Solvent Impregnated Resin (SIR) material was prepared by impregnating a trialkyl phosphine oxide functionalized ionic liquid (IL) into an inert polymeric material XAD-7. A series of SIR materials were prepared by varying the IL quantity. Sorption of both U(VI) and Pu(IV) were found to increase with increasing IL concentration in SIR up to an optimum IL concentration of 435 mg g-1 of SIR beyond which no effect of IL concentration was observed. A change of mechanism of sorption for U(VI) by SIR was observed in comparison to solvent extraction. The dependency of U(VI) sorption with nitric acid concentration showed a reverse trend compared to solvent extraction studies while for Pu(IV) the trend remained same as observed with solvent extraction. Sorption of both the radionuclides was found to follow pseudo second order mechanism and Langmuir adsorption isotherm. Distribution co-efficient measurements on IL impregnated SIR showed highly selective sorption of U(VI) and Pu(IV) over other trivalent f-elements and fission products from nitric acid medium.

Carbon nano tubes functionalized with novel functional group- amido-amine for sorption of actinides.

The manuscript presents the results on the sorption of U(VI), Am(III) & Eu(III) from pH medium by a novel amido-amine functionalized multiwalled carbon nanotube (MWCNT). The novel functional group was introduced in the MWCNT by two step processes and characterized by various instrumental techniques like Scanning Electron Microscopy (SEM), Raman and X-ray Photoelectron Spectroscopy (XPS). The sorption process was found to be highly dependent on the pH of the solution with maximum sorption for both 233U, 241Am & 152+154Eu at pH 7.0. Kinetics of sorption was found to be fast with equilibrium reached in ∼15min and the sorption was found to be following pseudo 2nd order kinetics for the radionuclides. The sorption for both 233U and 152+154Eu followed Langmuir sorption model with maximum sorption capacity of 20.66mg/g and 16.1mg/g respectively. This has been explained by DFT calculations which shows that more negative solvation energy of U(VI) compared to Am(III) and Eu(III) and stronger U-MWCNT-AA complex is responsible for higher sorption capacity of U(VI) compared to Am(III) and Eu(III).The synthesized amido-amine functionalized MWCNT is a very promising candidate for removal of actinides and lanthanides from waste water solution with high efficiency.

BenzoDODA grafted polymeric resin-Plutonium selective solid sorbent.

A new ligand grafted polymeric resin (BenzoDODA SDVB) was synthesized by covalently attaching plutonium selective ligand (BenzoDODA) on to styrene divinyl benzene (SDVB) polymer matrix. BenzoDODA SDVB resin was evaluated for separation and recovery of plutonium(IV) from nitric acid medium. Sorption of Pu(IV) was found to decrease with the increase in nitric acid concentration, with very small sorption above 7.0M HNO3. Sorption kinetics was fast enough to achieve the equilibrium within 60min of contact where the kinetic data fitted well to pseudo-second-order model. Sorption isotherm data fitted well to Langmuir model suggesting chemical interaction between the BenzoDODA moiety and plutonium(IV) ions. Sorption studies with some of representative radionuclides of high level waste showed that BenzoDODA SDVB is selective and therefore could be a promising solid sorbent for separation and recovery of plutonium. Further, the theoretical calculations done on BenzoDODA SDVB resin suggested Pu(NO3)4·BenzoDODA (1:1) sorbed complex conformed to generally observed square antiprism geometry of the plutonium complexes, with contributions from oxygen atoms of four nitrate ions as well as from four oxygen atoms present in BenzoDODA (two phenolic ether oxygen atoms and two carbonyl oxygen atoms of amidic moiety).

Efficient transport of Am(III) from nitric acid medium using a new conformationally constrained (N,N,N',N'-tetra-2-ethylhexyl)7-oxabicyclo[2.2.1]heptane-2,3-dicarboxamide across a supported liquid membrane.

Am(III) is one of the most hazardous radionuclide present in nuclear fuel cycle. A new conformationally constrained diamide, (N,N,N',N'-tetra-2-ethylhexyl)7-oxabicyclo[2.2.1]heptane-2,3-dicarboxamide (OBDA) was studied for Am(III) transport from HNO3 medium across a Supported Liquid Membrane. Transport rate was observed to be significantly fast with ∼95% transport of Am(III) within 1h using 0.1M OBDA in the presence of 15% isodecyl alcohol (IDA)/n-dodecane as carrier. The mechanism of transport was investigated by studying various parameters like feed HNO3/NaNO3 concentration, OBDA concentration in the membrane, membrane pore size, membrane thickness etc. From these studies, the mechanism of transport was found to be diffusion controlled with diffusion co-efficient value of 5.1×10(-6)cm(2)/s. The membrane was found to be highly selective for tri- and tetra-valent actinides, and trivalent lanthanides. OBDA based membrane was found to be stable for at least for ten consecutive cycles of operation.

HIV in Canada: 2009 to 2014.

BACKGROUND: Between 1996 and 2008, the number of newly reported HIV cases in Canada fluctuated between approximately 2,100 and 2,700 cases per year. OBJECTIVE: To describe the recent trends in new diagnoses of HIV in Canada between 2009 and 2014 by age group, sex, exposure category, race/ethnicity, and region, as well as the number of perinatally HIV-exposed infants. METHODS: HIV data were compiled from two databases. The National HIV/AIDS Surveillance System is a passive surveillance system that gathers non-nominal data on a voluntary basis from all the provinces and territories of all cases that meet the national case definition, and includes data on age group, sex, race/ethnicity, country of birth, and exposure categories. The Canadian Perinatal HIV Surveillance Program is a sentinel-based surveillance system; non-nominal data is obtained through a national confidential survey completed by participating physicians. RESULTS: Since 2009 the number of new HIV cases has slowly but steadily declined from 2,391 cases in 2009 to 2,044 in 2014, which is the lowest number of annual HIV cases seen in the last two decades. The largest proportion (32%) of new HIV cases continues to be diagnosed among those 30 to 39 years of age, but the proportion of cases diagnosed among those 50 years of age or over has increased from 15% in 2009 to slightly over 20% in 2014. Approximately 75% of newly diagnosed cases are males and 25% females. In males, the most common exposure category (60%) was men who have sex with men. In females, the most common exposure category (66%) was heterosexual contact followed by injection drug use (27%). Race/ethnicity varied by sex. In males, over 50% were White, 14% were Aboriginal and 13% Black. In females, 35% were Black, 35% were Aboriginal and 22% were White. There were regional variations in HIV rates across Canada. Between 2009 and 2014, the number of perinatally HIV-exposed infants varied between 200 and 249 but the percentage of perinatal treatment increased from 87% in 2009 to 97% in 2014. CONCLUSION: The annual number of reported HIV cases in Canada has been declining in recent years. The proportion of HIV-positive mothers receiving treatment has increased and the number of confirmed HIV-infected infants has decreased.

DNA sequence and analysis of human chromosome 9.

Chromosome 9 is highly structurally polymorphic. It contains the largest autosomal block of heterochromatin, which is heteromorphic in 6-8% of humans, whereas pericentric inversions occur in more than 1% of the population. The finished euchromatic sequence of chromosome 9 comprises 109,044,351 base pairs and represents >99.6% of the region. Analysis of the sequence reveals many intra- and interchromosomal duplications, including segmental duplications adjacent to both the centromere and the large heterochromatic block. We have annotated 1,149 genes, including genes implicated in male-to-female sex reversal, cancer and neurodegenerative disease, and 426 pseudogenes. The chromosome contains the largest interferon gene cluster in the human genome. There is also a region of exceptionally high gene and G + C content including genes paralogous to those in the major histocompatibility complex. We have also detected recently duplicated genes that exhibit different rates of sequence divergence, presumably reflecting natural selection.

The DNA sequence and comparative analysis of human chromosome 10.

The finished sequence of human chromosome 10 comprises a total of 131,666,441 base pairs. It represents 99.4% of the euchromatic DNA and includes one megabase of heterochromatic sequence within the pericentromeric region of the short and long arm of the chromosome. Sequence annotation revealed 1,357 genes, of which 816 are protein coding, and 430 are pseudogenes. We observed widespread occurrence of overlapping coding genes (either strand) and identified 67 antisense transcripts. Our analysis suggests that both inter- and intrachromosomal segmental duplications have impacted on the gene count on chromosome 10. Multispecies comparative analysis indicated that we can readily annotate the protein-coding genes with current resources. We estimate that over 95% of all coding exons were identified in this study. Assessment of single base changes between the human chromosome 10 and chimpanzee sequence revealed nonsense mutations in only 21 coding genes with respect to the human sequence.

The DNA sequence and analysis of human chromosome 13.

Chromosome 13 is the largest acrocentric human chromosome. It carries genes involved in cancer including the breast cancer type 2 (BRCA2) and retinoblastoma (RB1) genes, is frequently rearranged in B-cell chronic lymphocytic leukaemia, and contains the DAOA locus associated with bipolar disorder and schizophrenia. We describe completion and analysis of 95.5 megabases (Mb) of sequence from chromosome 13, which contains 633 genes and 296 pseudogenes. We estimate that more than 95.4% of the protein-coding genes of this chromosome have been identified, on the basis of comparison with other vertebrate genome sequences. Additionally, 105 putative non-coding RNA genes were found. Chromosome 13 has one of the lowest gene densities (6.5 genes per Mb) among human chromosomes, and contains a central region of 38 Mb where the gene density drops to only 3.1 genes per Mb.

The physical maps for sequencing human chromosomes 1, 6, 9, 10, 13, 20 and X.

We constructed maps for eight chromosomes (1, 6, 9, 10, 13, 20, X and (previously) 22), representing one-third of the genome, by building landmark maps, isolating bacterial clones and assembling contigs. By this approach, we could establish the long-range organization of the maps early in the project, and all contig extension, gap closure and problem-solving was simplified by containment within local regions. The maps currently represent more than 94% of the euchromatic (gene-containing) regions of these chromosomes in 176 contigs, and contain 96% of the chromosome-specific markers in the human gene map. By measuring the remaining gaps, we can assess chromosome length and coverage in sequenced clones.

Integration of cytogenetic landmarks into the draft sequence of the human genome.

We have placed 7,600 cytogenetically defined landmarks on the draft sequence of the human genome to help with the characterization of genes altered by gross chromosomal aberrations that cause human disease. The landmarks are large-insert clones mapped to chromosome bands by fluorescence in situ hybridization. Each clone contains a sequence tag that is positioned on the genomic sequence. This genome-wide set of sequence-anchored clones allows structural and functional analyses of the genome. This resource represents the first comprehensive integration of cytogenetic, radiation hybrid, linkage and sequence maps of the human genome; provides an independent validation of the sequence map and framework for contig order and orientation; surveys the genome for large-scale duplications, which are likely to require special attention during sequence assembly; and allows a stringent assessment of sequence differences between the dark and light bands of chromosomes. It also provides insight into large-scale chromatin structure and the evolution of chromosomes and gene families and will accelerate our understanding of the molecular bases of human disease and cancer.

The DNA sequence and comparative analysis of human chromosome 20.

The finished sequence of human chromosome 20 comprises 59,187,298 base pairs (bp) and represents 99.4% of the euchromatic DNA. A single contig of 26 megabases (Mb) spans the entire short arm, and five contigs separated by gaps totalling 320 kb span the long arm of this metacentric chromosome. An additional 234,339 bp of sequence has been determined within the pericentromeric region of the long arm. We annotated 727 genes and 168 pseudogenes in the sequence. About 64% of these genes have a 5' and a 3' untranslated region and a complete open reading frame. Comparative analysis of the sequence of chromosome 20 to whole-genome shotgun-sequence data of two other vertebrates, the mouse Mus musculus and the puffer fish Tetraodon nigroviridis, provides an independent measure of the efficiency of gene annotation, and indicates that this analysis may account for more than 95% of all coding exons and almost all genes.

High-resolution landmark framework for the sequence-ready mapping of Xq23-q26.1.

We have established a landmark framework map over 20-25 Mb of the long arm of the human X chromosome using yeast artificial chromosome (YAC) clones. The map has approximately one landmark per 45 kb of DNA and stretches from DXS7531 in proximal Xq23 to DXS895 in proximal Xq26, connecting to published framework maps on its proximal and distal sides. There are three gaps in the framework map resulting from the failure to obtain clone coverage from the YAC resources available. Estimates of the maximum sizes of these gaps have been obtained. The four YAC contigs have been positioned and oriented using somatic-cell hybrids and fluorescence in situ hybridization, and the largest is estimated to cover approximately 15 Mb of DNA. The framework map is being used to assemble a sequence-ready map in large-insert bacterial clones, as part of an international effort to complete the sequence of the X chromosome. PAC and BAC contigs currently cover 18 Mb of the region, and from these, 12 Mb of finished sequence is available.

Determination of trace impurities in uranium, thorium and plutonium matrices by solvent extraction and inductively coupled plasma atomic emission spectrometry.

Studies on the determination of trace metallic impurities in nuclear materials such as uranium, thorium and plutonium are described. The bulk of the matrix is separated by batch extraction from their nitric acid solutions using 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate (KSM-17, equivalent to PC88-A). The final aqueous phase containing the metallic impurities is fed to a high-temperature source inductively coupled plasma and the analysis is carried out employing a computer-controlled multichannel direct-reading spectrometer. The studies also included the recovery of impurities at various acidities and spectral interferences of the above matrices over the analyte elements. Based on the above studies, methods were standardized for the determination of 19 elements, viz. Al, B, Be, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Si, Zn, Ce, Dy, Eu, Gd and Sm, in U/Th/Pu solutions. The relative standard deviation for various elements is in the range 1-5%.