1,476 research outputs found
Seasonal cycling of sulfur and iron in porewaters of a Delaware salt marsh
An extensive pore water data set has been gathered in the Great Marsh, Delaware over various seasons, salinities, and tides. The data all point to a complimentary redox cycle for sulfur and iron which operates seasonally and tidally. Surface oxidizing conditions prevail in summer, with more reducing conditions at depth during the winter. During the spring tides which flood the marsh, pyrite oxidation occurs releasing excess dissolved iron (II) and sulfate to the porewaters, and precipitating authigenic solid iron phases. The redox conditions in the porewaters of the upper zone during the summer is poised between mildly oxidizing and mildly reducing conditions as shown by pE calculations. This redox environment and intermediate iron-sulfur redox species may be important for the stimulation of plant growth (photosynthesis) and sustenance of a viable microbial community (heterotrophy and chemoautropy)
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BRAIN: innovative neurotechnologies for imaging and therapeutics
Conceived with the aim of meeting the needs of the neurobiology and clinical communities, the Brain Research through Advancing Innovative Technologies (BRAIN) Initiative builds on the lessons learned from major projects in genetics, such as the Human Genome Project. It concentrates on the use of new imaging technologies in conjunction with genomics to inform therapeutic decisions
Notes and Comments: The Right to a Speedy Trial in Maryland
In the wake of the Supreme Court\u27s 1972 decision in Barker v. Wingo, Maryland appellate courts have enforced more rigorously the right of criminal defendants to a speedy trial. This article surveys the application and treatment of the Barker criteria by the Maryland courts in recent decisions
Notes and Comments: The Right to a Speedy Trial in Maryland
In the wake of the Supreme Court\u27s 1972 decision in Barker v. Wingo, Maryland appellate courts have enforced more rigorously the right of criminal defendants to a speedy trial. This article surveys the application and treatment of the Barker criteria by the Maryland courts in recent decisions
A Dynamic Programming Approach to De Novo Peptide Sequencing via Tandem Mass Spectrometry
The tandem mass spectrometry fragments a large number of molecules of the
same peptide sequence into charged prefix and suffix subsequences, and then
measures mass/charge ratios of these ions. The de novo peptide sequencing
problem is to reconstruct the peptide sequence from a given tandem mass
spectral data of k ions. By implicitly transforming the spectral data into an
NC-spectrum graph G=(V,E) where |V|=2k+2, we can solve this problem in
O(|V|+|E|) time and O(|V|) space using dynamic programming. Our approach can be
further used to discover a modified amino acid in O(|V||E|) time and to analyze
data with other types of noise in O(|V||E|) time. Our algorithms have been
implemented and tested on actual experimental data.Comment: A preliminary version appeared in Proceedings of the 11th Annual
ACM-SIAM Symposium on Discrete Algorithms, pages 389--398, 200
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Mutants of Cre recombinase with improved accuracy
Despite rapid advances in genome engineering technologies, inserting genes into precise locations in the human genome remains an outstanding problem. It has been suggested that site-specific recombinases can be adapted towards use as transgene delivery vectors. The specificity of recombinases can be altered either with directed evolution or via fusions to modular DNA-binding domains. Unfortunately, both wildtype and altered variants often have detectable activities at off-target sites. Here we use bacterial selections to identify mutations in the dimerization surface of Cre recombinase (R32V, R32M, and 303GVSdup) that improve the accuracy of recombination. The mutants are functional in bacteria, in human cells, and in vitro (except for 303GVSdup, which we did not purify), and have improved selectivity against both model off-target sites and the entire E. coli genome. We propose that destabilizing binding cooperativity may be a general strategy for improving the accuracy of dimeric DNA-binding proteins
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