Observation of electron transfer mediated decay in aqueous solution

Photoionization is at the heart of X ray photoelectron spectroscopy XPS , which gives access to important information on a sample s local chemical environment. Local and non local electronic decay after photoionization in which the refilling of core holes results in electron emission from either the initially ionized species or a neighbour, respectively have been well studied. However, electron transfer mediated decay ETMD , which involves the refilling of a core hole by an electron from a neighbouring species, has not yet been observed in condensed phase. Here we report the experimental observation of ETMD in an aqueous LiCl solution by detecting characteristic secondary low energy electrons using liquid microjet soft XPS. Experimental results are interpreted using molecular dynamics and high level ab initio calculations. We show that both solvent molecules and counterions participate in the ETMD processes, and different ion associations have distinctive spectral fingerprints. Furthermore, ETMD spectra are sensitive to coordination numbers, ion solvent distances and solvent arrangemen

Polychaete invader enhances resource utilization in a species-poor system

Ecosystem consequences of biodiversity change are often studied from a species loss perspective, while the effects of invasive species on ecosystem functions are rarely quantified. In this experimental study, we used isotope tracers to measure the incorporation and burial of carbon and nitrogen from a simulated spring phytoplankton bloom by communities of one to four species of deposit-feeding macrofauna found in the species-poor Baltic Sea. The recently invading polychaete Marenzelleriaarctia, which has spread throughout the Baltic Sea, grows more rapidly than the native species Monoporeia affinis, Pontoporeia femorata (both amphipods) and Macoma balthica (a bivalve), resulting in higher biomass increase (biomass production) in treatments including the polychaete. Marenzelleria incorporated and buried bloom material at rates similar to the native species. Multi-species treatments generally had higher isotope incorporation, indicative of utilization of bloom material, than expected from monoculture yields of the respective species. The mechanism behind this observed over-yielding was mainly niche complementarity in utilization of the bloom input, and was more evident in communities including the invader. In contrast, multi-species treatments had generally lower biomass increase than expected. This contrasting pattern suggests that there is little overlap in resource use of freshly deposited bloom material between Marenzelleria and the native species but it is likely that interference competition acts to dampen resulting community biomass. In conclusion, an invasive species can enhance incorporation and burial of organic matter from settled phytoplankton blooms, two processes fundamental for marine productivity

Effects of the endpoint adjudication process on the results of a randomised controlled trial: The ADVANCE trial

BACKGROUND Endpoint adjudication committees (EPAC) are widely used in clinical trials. The aim of the present analysis is to assess the effects of the endpoint adjudication process on the main findings of the ADVANCE trial (Trial registration: ClinicalTrials.gov NCT00145925). METHODS AND FINDINGS The ADVANCE trial was a multicentre, 2×2 factorial randomised controlled trial of blood pressure lowering and intensive blood glucose control in 11140 patients with type 2 diabetes. Primary outcomes were major macrovascular (nonfatal myocardial infarction, nonfatal stroke and cardiovascular death) and microvascular (new or worsening nephropathy and retinopathy) events. Suspected primary outcomes were initially reported by the investigators at the 215 sites with subsequent adjudication by the EPAC. The EPAC also adjudicated upon potential events identified directly by ongoing screening of all reported events. Over a median follow-up of 5 years, the site investigators reported one or more primary outcomes among 2443 participants. After adjudication these events were confirmed for 2077 (85%) with 48 further events added through the EPAC-led database screening process. The estimated relative risk reductions (95% confidence intervals) in the primary outcome for the blood pressure lowering comparison were 8% (−1 to 15%) based on the investigator-reported events and 9% (0 to 17%) based on the EPAC-based events (P for homogeneity = 0.70). The corresponding findings for the glucose comparison were 8% (1 to 15%) and 10% (2% to 18%) (P for homogeneity = 0.60). The effect estimates were also highly comparable when studied separately for macrovascular events and microvascular events for both comparisons (all P for homogeneity>0.6). CONCLUSIONS The endpoint adjudication process had no discernible impact on the main findings in ADVANCE. These data highlight the need for careful consideration of the likely impact of an EPAC on the findings and conclusions of clinical trials prior to their establishment.Jun Hata, Hisatomi Arima, Sophia Zoungas,, Greg Fulcher, Carol Pollock, Mark Adams, John Watson, Rohina Joshi, Andre Pascal Kengne, Toshiharu Ninomiya, Craig Anderson, Mark Woodward, Anushka Patel, Giuseppe Mancia, Neil Poulter, Stephen MacMahon, John Chalmers, Bruce Neal, on behalf of the ADVANCE Collaborative Grou

Continuous Flow Reactor for the Production of Stable Amyloid Protein Oligomers

The predominant working hypothesis of Alzheimer's disease is that the proximate pathologic agents are oligomers of the amyloid β-protein (Aβ). "Oligomer" is an ill-defined term. Many different types of oligomers have been reported, and they often exist in rapid equilibrium with monomers and higher-order assemblies. This has made formal structure-activity determinations difficult. Recently, Ono et al. [Ono, K., et al. (2009) Proc. Natl. Acad. Sci. U.S.A. 106, 14745-14750] used rapid, zero-length, in situ chemical cross-linking to stabilize the oligomer state, allowing the isolation and study of pure populations of oligomers of a specific order (number of Aβ monomers per assembly). This approach was successful but highly laborious and time-consuming, precluding general application of the method. To overcome these difficulties, we developed a "continuous flow reactor" with the ability to produce theoretically unlimited quantities of chemically stabilized Aβ oligomers. We show, in addition to its utility for Aβ, that this method can be applied to a wide range of other amyloid-forming proteins