Geomorphology of Ulu Peninsula, James Ross Island, Antarctica

This study presents a 1:25,000 geomorphological map of the northern sector of Ulu Peninsula, James Ross Island, Antarctic Peninsula. The map covers an area of c. 250 km2, and documents the landforms and surficial sediments of one of the largest ice-free areas in Antarctica, based on remote sensing and field-based mapping. The large-scale landscape features are determined by the underlying Cretaceous sedimentary and Neogene volcanic geology, which has been sculpted by overlying ice masses during glacial periods. Paraglacial and periglacial features are superimposed upon remnant glacial features, reflecting the post-glacial evolution of the landscape. The study area can be broadly separated into three geomorphological sectors, according to the dominant contemporary Earth-surface processes; specifically, a glacierised southern sector, a paraglacial-dominated eastern sector, and a periglacial-dominated central/northern sector. This map provides a basis for further interdisciplinary research, and insight into the potential future landscape evolution of other parts of the Antarctic Peninsula as the climate warms

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

PerR controls Mn-dependent resistance to oxidative stress in Neisseria gonorrhoeae

In previous studies it has been established that resistance to superoxide by Neisseria gonorrhoeae is dependent on the accumulation of Mn(II) ions involving the ABC transporter, MntABC. A mutant strain lacking the periplasmic binding protein component (MntC) of this transport system is hypersensitive to killing by superoxide anion. In this study the mntC mutant was found to be more sensitive to H2O2 killing than the wild-type. Analysis of regulation of MntC expression revealed that it was de-repressed under low Mn(II) conditions. The N. gonorrhoeae mntABC locus lacks the mntR repressor typically found associated with this locus in other organisms. A search for a candidate regulator of mntABC expression revealed a homologue of PerR, a Mn-dependent peroxide-responsive regulator found in Gram-positive organisms. A perR mutant expressed more MntC protein than wild-type, and expression was independent of Mn(II), consistent with a role for PerR as a repressor of mntABC expression. The PerR regulon of N. gonorrhoeae was defined by microarray analysis and includes ribosomal proteins, TonB-dependent receptors and an alcohol dehydrogenase. Both the mntC and perR mutants had reduced intracellular survival in a human cervical epithelial cell model.Hsing-Ju Wu, Kate L. Seib, Yogitha N. Srikhanta, Stephen P. Kidd, Jennifer L. Edwards, Tina L. Maguire, Sean M. Grimmond, Michael A. Apicella, Alastair G. McEwan and Michael P. Jenning