Production, Characterization and Corrosion Analysis of Multiphase Alloy-Ceramic Composites

This study addressed the possible use of alloy/ceramic composite waste forms to immobilize metallic and oxide waste streams generated during the electrochemical reprocessing of spent reactor fuel using a single waste form. A representative composite material (AOC410) was made to evaluate the microstructure and corrosion behavior at alloy/ceramic interfaces by reacting 410 stainless steel with Zr, Mo, and a mixture of lanthanide oxides. Zr metal reacted with lanthanide oxides to generate lanthanide zirconates, which combined with the unreacted lanthanide oxides to form a porous ceramic network that filled with alloy to produce a composite puck. Alloy present in excess of the pore volume of the ceramic generated a metal bead on top of the puck. The alloys in the composite and forming the bead were both mixtures of martensite grains and ferrite grains bearing carbide precipitates; FeCrMo intermetallic phases also precipitated at ferrite grain boundaries within the composite puck. Micrometer-thick regions of ferrite surrounding the carbides were sensitized and corroded preferentially in electrochemical tests. The lanthanide oxides dissolved chemically, but the lanthanide zirconates did not dissolve and are suitable host phases. The presence of oxide phases did not affect corrosion of the neighboring alloy phases. The effects of added Ru and Pd on the microstructure and electrochemical behaviour of a composite material (AOC410N) made by melting those metals with AISI 410 stainless steel, Zr, Mo, and lanthanide oxides were assessed using electrochemical and microscopic methods. The noble metals alloyed with the steel to provide solid solution strengthening and inhibit carbide/nitride formation. A passive film formed during electrochemical tests in acidic NaCl solution, but became less effective as corrosion progressed and regions over the intermetallics eventually failed. A U-bearing composite (AOCU) was made for corrosion testing by reacting HT9 steel to represent fuel cladding, Zr and Mo to simulate metallic fuel waste, and a mixture of ZrO2, Nd2O3, and UO2 to represent oxide wastes. The Nd2O3 and some of the uranium reacted with Zr to form zirconates and the remaining uranium was reduced and incorporated in Fe-Zr-U intermetallics. Two Fe-Cr-Mo intermetallics also formed, which are expected to host Tc. The results of microstructure characterizations of the intermetallic and ceramic phases that were generated and tests conducted to evaluate their corrosion behaviors will be presented. Test results suggest composite waste forms will provide flexibility for immobilizing complex waste streams by accommodating both metallic and oxidized waste streams in durable host phases while lowering waste form production and disposal costs

SRComp: Short Read Sequence Compression Using Burstsort and Elias Omega Coding

<div><p>Next-generation sequencing (NGS) technologies permit the rapid production of vast amounts of data at low cost. Economical data storage and transmission hence becomes an increasingly important challenge for NGS experiments. In this paper, we introduce a new non-reference based read sequence compression tool called SRComp. It works by first employing a fast string-sorting algorithm called burstsort to sort read sequences in lexicographical order and then Elias omega-based integer coding to encode the sorted read sequences. SRComp has been benchmarked on four large NGS datasets, where experimental results show that it can run 5–35 times faster than current state-of-the-art read sequence compression tools such as BEETL and SCALCE, while retaining comparable compression efficiency for large collections of short read sequences. SRComp is a read sequence compression tool that is particularly valuable in certain applications where compression time is of major concern.</p></div

New method for synthesis of EZH2 methyltransferase inhibitor GSK126

<p>GSK126 is a potent small-molecule inhibitor of S-adenosyl-methionine-competitive EZH2 methyltransferase and has the potential to be used clinically for preventing unwanted histone methylation of tumor suppressor genes. In this article, we describe a new synthetic route that has been developed for synthesizing the title compound through nine steps, starting from 2,5-dibromobenzoic acid. This synthetic method is economical and suitable for multigram-scale preparation of GSK126 and related N-alkylated indole derivatives.</p

Comparison of compression performance of SRComp to gzip, bzip2, BEETL and SCALCE.

<p>BEETL is run in combination with PPMd, and SCALCE in combination with gzip. In the above, p-mem and d-time denote the compression peak memory usage (megabytes) and decompression CPU time, respectively. Times are averaged over five runs.</p

Comparison of compression CPU time and bit rates of Elias omega coding to gzip and bzip2 on sorted read sequences.

<p>In the above, c-time means compression CPU time and bpb denotes bits per base. Times are averaged over five runs.</p

The algorithm overview for compression.

<p>(A) After five input read sequences are loaded in memory, we build two arrays of pointers. The first array (upper) contains pointers each of which points to a read sequence, whereas the second array (lower) contains pointers each of which points to an occurrence of the ambiguous base N. (B) Before burstsort starts, all the ambiguous bases are substituted with base G. During sorting, read sequences remain at the same physical place in memory and only their respective pointers in the first array are moved into sort order. At the end, read sequences are retrieved in order via the first pointer array. (C) Once the encoding of ordered read sequences is completed, all the ambiguous bases are substituted back via the second pointer array, which enables finding the location of every ambiguous base within the collection of sorted read sequences.</p

Some basic statistics for datasets used in the experiments.

<p>As the paired-end reads from the experiment SRX006998 are of different length, we include in this dataset only reads from one end.</p

Evaluation of SRComp on simulated datasets of varying read lengths and genome coverage depths.

<p>SCALCE's decompression crashed on two datasets tested, one consisting of 35 bp reads at 31 coverage and the other consisting of 50 bp reads at 44 coverage. Hence, their corresponding decompression times are indicated by a hyphen mark (−) in the above table. Times are averaged over five runs.</p

Comparison of CPU time needed to sort large collections of reads.

<p>Designations of these algorithm variants can be found in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081414#pone.0081414-Sinha1" target="_blank">[14]</a>. Times are averaged over five runs.</p

A burst trie built from ten read sequences.

<p>The ten read sequences used are {CGCA, CAAG, TGCT, CGTG, CGTT, GACG, CACT, TGCT, CAAT, CGTG}. This burst trie has three trie nodes and five buckets. The maximum capacity of a bucket is assumed to be three read sequences.</p