Ion exchange determines iodine-131 concentration in aqueous samples

Inorganic radioiodide in aqueous media is analyzed by separating the radioactive iodine-131 as the iodide ion on a silver chloride column. The activity in the final precipitate may be determined by beta or gamma counting

Direct determination of lead-210 by liquid-scintillation counting

Soft betas, the internal conversion electrons, and unconverted gamma rays from lead-210 are efficiently detected in a liquid scintillation counting system with efficiency of 97 percent. The counter is interfaced with a multichannel pulse height analyzer. The spectra obtained is stored on paper tape and plotted on an x-y plotter

Bounded Model Checking of State-Space Digital Systems: The Impact of Finite Word-Length Effects on the Implementation of Fixed-Point Digital Controllers Based on State-Space Modeling

The extensive use of digital controllers demands a growing effort to prevent design errors that appear due to finite-word length (FWL) effects. However, there is still a gap, regarding verification tools and methodologies to check implementation aspects of control systems. Thus, the present paper describes an approach, which employs bounded model checking (BMC) techniques, to verify fixed-point digital controllers represented by state-space equations. The experimental results demonstrate the sensitivity of such systems to FWL effects and the effectiveness of the proposed approach to detect them. To the best of my knowledge, this is the first contribution tackling formal verification through BMC of fixed-point state-space digital controllers.Comment: International Symposium on the Foundations of Software Engineering 201

BLM and RMI1 alleviate RPA inhibition of topoIIIα decatenase activity

RPA is a single-stranded DNA binding protein that physically associates with the BLM complex. RPA stimulates BLM helicase activity as well as the double Holliday junction dissolution activity of the BLM-topoisomerase IIIα complex. We investigated the effect of RPA on the ssDNA decatenase activity of topoisomerase IIIα. We found that RPA and other ssDNA binding proteins inhibit decatenation by topoisomerase IIIα. Complex formation between BLM, TopoIIIα, and RMI1 ablates inhibition of decatenation by ssDNA binding proteins. Together, these data indicate that inhibition by RPA does not involve species-specific interactions between RPA and BLM-TopoIIIα-RMI1, which contrasts with RPA modulation of double Holliday junction dissolution. We propose that topoisomerase IIIα and RPA compete to bind to single-stranded regions of catenanes. Interactions with BLM and RMI1 enhance toposiomerase IIIα activity, promoting decatenation in the presence of RPA

Results with the Talent thoracic stent graft in the VALOR trial

OBJECTIVE: We report the 5-year outcomes of thoracic endovascular aneurysm repair (TEVAR) using the Medtronic Vascular Talent Thoracic Stent Graft System (Medtronic Vascular, Santa Rosa, Calif) in patients considered low or moderate risk for open surgical repair. METHODS: The Evaluation of the Medtronic Vascular Talent Thoracic Stent Graft System for the Treatment of Thoracic Aortic Aneurysms (VALOR) trial was a prospective, nonrandomized, multicenter, pivotal study conducted at 38 U.S. sites. Between December 2003 and June 2005, VALOR enrolled 195 patients who were low or moderate risk (0, 1, and 2) per the modified Society for Vascular Surgery and American Association for Vascular Surgery criteria. The patients had fusiform thoracic aortic aneurysms (TAAs) and/or focal saccular TAAs/penetrating atherosclerotic ulcers. Standard follow-up interval examinations were conducted at 1 month, 6 months, 1 year, and annually thereafter. RESULTS: Over the 5-year follow-up, 76 deaths occurred (43.9%). Freedom from all-cause mortality was 83.9% at 1 year and 58.5% at 5 years. Most deaths were due to cardiac, pulmonary or cancer-related causes. Freedom from aneurysm-related mortality (ARM) was 96.9% at 1 year and 96.1% at 5 years. There was only 1 case of ARM after the first year of follow-up. Over the 5-year follow-up period, four patients were converted to open surgery and four patients experienced aneurysm rupture. The 5-year freedom from aneurysm rupture was 97.1% and the 5-year freedom from conversion to surgery was 97.1%. The incidence of stent graft migration (>10 mm) was ≤ 1.8% in each year of follow-up. The rate of type I endoleak was 4.6% at 1 month, 6.3% from 1 month to 1 year, and 3.8% during year 5. The rate of type III endoleak was 1.3% at 1 month, 1.9% from 1 month to 1 year, and 1.9% during year 5. Through 5 years, 28 patients (14.4%) underwent 31 additional endovascular procedures on the original target lesion. The 5-year freedom from secondary endovascular procedures was 81.5%. CONCLUSIONS: Through 5-year follow-up in patients who were candidates for open surgical repair, TEVAR using the Talent Thoracic Stent Graft System has demonstrated sustained protection from ARM, aneurysm rupture, and conversion to surgery, and durable stent graft performance. Close patient follow-up remains essential after TEVAR

The conserved C-terminus of the PcrA/UvrD helicase interacts directly with RNA polymerase

Copyright: © 2013 Gwynn et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by a Wellcome Trust project grant to MD (Reference: 077368), an ERC starting grant to MD (Acronym: SM-DNA-REPAIR) and a BBSRC project grant to PM, NS and MD (Reference: BB/I003142/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

The First State of the Carbon Cycle Report (SOCCR)

A primary objective of the U.S. Climate Change Science Program (CCSP) is to provide the best possible scientific information to support public discussion, as well as government and private sector decision making, on key climate-related issues. To help meet this objective, the CCSP has identified an initial set of 21 Synthesis and Assessment Products (SAPs) that address its highest priority research, observation, and decision support needs. This report-CCSP SAP 2.2-addresses Goal 2 of the CCSP Strategic Plan: Improve quantification of the forces bringing about changes in the Earth's climate and related systems. The report provides a synthesis and integration of the current knowledge of the North American carbon budget and its context within the global carbon cycle. In a format useful to decision makers, it (1) summarizes our knowledge of carbon cycle properties and changes relevant to the contributions of and impacts upon North America and the rest of the world, and (2) provides scientific information for decision support focused on key issues for carbon management and policy. Consequently, this report is aimed at both the decision-maker audience and to the expert scientific and stakeholder communities

Position of the Third Na+ Site in the Aspartate Transporter GltPh and the Human Glutamate Transporter, EAAT1

Glutamate transport via the human excitatory amino acid transporters is coupled to the co-transport of three Na+ ions, one H+ and the counter-transport of one K+ ion. Transport by an archaeal homologue of the human glutamate transporters, GltPh, whose three dimensional structure is known is also coupled to three Na+ ions but only two Na+ ion binding sites have been observed in the crystal structure of GltPh. In order to fully utilize the GltPh structure in functional studies of the human glutamate transporters, it is essential to understand the transport mechanism of GltPh and accurately determine the number and location of Na+ ions coupled to transport. Several sites have been proposed for the binding of a third Na+ ion from electrostatic calculations and molecular dynamics simulations. In this study, we have performed detailed free energy simulations for GltPh and reveal a new site for the third Na+ ion involving the side chains of Threonine 92, Serine 93, Asparagine 310, Aspartate 312, and the backbone of Tyrosine 89. We have also studied the transport properties of alanine mutants of the coordinating residues Threonine 92 and Serine 93 in GltPh, and the corresponding residues in a human glutamate transporter, EAAT1. The mutant transporters have reduced affinity for Na+ compared to their wild type counterparts. These results confirm that Threonine 92 and Serine 93 are involved in the coordination of the third Na+ ion in GltPh and EAAT1