Coarse-Grained Model of Dielectric Geometry-Modified Screened Electrostatic Protein-Protein Interactions

To refine a coarse-grained model of protein interactions, we seek to conveniently represent how dielectric interface geometry and charge placement affect screened aqueous electrostatic interactions. We study two neighboring low dielectric spheres with near-surface charges, for which we solve the linearized Poisson-Boltzmann equation as a function of sphere-sphere separation. The spheres have ~15Å diameters and internal static dielectric coefficients of 3. The solvent’s Debye length is 6Å. These parameters are consistent with our charge-regulation model of bovine γB-Crystallin and with a wealth of previous experimental data for solutions of this protein. For a fixed on- or off-axis charge in the first sphere, the two-dimensional angular dependence of the near-surface potential in the second sphere is well-fit by a modified, rotated, possibly off-center Student t-distribution at each sphere-sphere distance. We use the full electrostatic solution to fit the parameters of these Student t-distributions as functions of sphere-sphere separation and angular placement of the charge in the first sphere. The approximation developed here is much more accurate than the unmodified Debye-Hückel screened potential and shows the potential for further refinement

Mycorrhizal co-invasion and novel interactions depend on neighborhood context

© 2015 by the Ecological Society of America. Biological invasions are a rapidly increasing driver of global change, yet fundamental gaps remain in our understanding of the factors determining the success or extent of invasions. For example, although most woody plant species depend on belowground mutualists such as mycorrhizal fungi and nitrogen-fixing bacteria, the relative importance of these mutualisms in conferring invasion success is unresolved. Here, we describe how neighborhood context (identity of nearby tree species) affects the formation of belowground ectomycorrhizal partnerships between fungi and seedlings of a widespread invasive tree species, Pseudotsuga menziesii (Douglas-fir), in New Zealand.We found that the formation of mycorrhizal partnerships, the composition of the fungal species involved in these partnerships, and the origin of the fungi (co-invading or native to New Zealand) all depend on neighborhood context. Our data suggest that nearby ectomycorrhizal host trees act as both a reservoir of fungal inoculum and a carbon source for late-successional and native fungi. By facilitating mycorrhization of P. menziesii seedlings, adult trees may alleviate mycorrhizal limitation at the P. menziesii invasion front. These results highlight the importance of studying biological invasions across multiple ecological settings to understand establishment success and invasion speed

Promoting Value Practice in Museums Creates Impact

This article examines how museological value discussion can offer a tool for museum professionals to engage themselves in the current discourse regarding building sustainable futures. The focus of the article is on collection care and collection development. It describes the latest interview and workshop results regarding museum values in the field of collection development among Finnish museum professionals and students. In addition, it emphasizes the integration of theoretical knowledge and its practical application. Promoting and creating opportunities for value discussion among museum professionals increases the ability of these professionals to further engage in such value-related discourse with various stakeholders. Eventually, the benefits of this kind of value-based discussions are to be seen in the more coherent and focused ones regarding museological values between and among various parties, be they museum professionals, politicians, students or museum visitors. The initial idea for the interviews, and subsequently the workshops as well, emerged from a collection development survey conducted in 2012 among Finnish art museums, which was published in 2016 by the author. Based on the material analyzed at that time, it became clear that the issue of active values in Finnish museums would need further study.Peer reviewe

The effect of regional citrate anti-coagulation on the coagulation system in critically ill patients receiving continuous renal replacement therapy for acute kidney injury - An observational cohort study

BACKGROUND: Regional anticoagulation with citrate is the recommended first line treatment for patients receiving continuous renal replacement therapy (CRRT). There is wide variability in filter patency which may be due to differences in patient characteristics and local practice. It is also possible that citrate has effects on primary and secondary haemostasis, fibrinolysis and platelet function that are still unknown. The primary aim of the study is to describe the effect of citrate on coagulation and fibrinolysis pathways in both the patient and the haemodialysis circuit. METHODS: The study will recruit 12 adult patients admitted to the intensive care unit, requiring CRRT with regional citrate anticoagulation for acute kidney injury. Patients with pre-existing thrombotic or bleeding tendencies will be excluded. Thrombin generation, clot lysis and platelet function will be measured at baseline and at 12, 24, 36, 48 and 72 h after commencing CRRT (from the patient and from the circuit). We will describe the evolution of parameters over time as well as the differences in parameters between the patient and the circuit. DISCUSSION: The study will provide new data on the effects of citrate during continuous renal replacement therapy which is not currently available. We will minimise confounding factors through the use of tight exclusion criteria and accept that this will slow down recruitment. Depending on the results, we hope to incorporate the findings into existing clinical guidelines and clinical practice with the aim to prevent premature filter clotting and interruptions in treatment. TRIAL REGISTRATION: The study was registered with clinicaltrials.gov on 10th June 2015 (NCT02486614)

Method to Improve Indium Bump Bonding via Indium Oxide Removal Using a Multi-Step Plasma Process

A process for removing indium oxide from indium bumps in a flip-chip structure to reduce contact resistance, by a multi-step plasma treatment. A first plasma treatment of the indium bumps with an argon, methane and hydrogen plasma reduces indium oxide, and a second plasma treatment with an argon and hydrogen plasma removes residual organics. The multi-step plasma process for removing indium oxide from the indium bumps is more effective in reducing the oxide, and yet does not require the use of halogens, does not change the bump morphology, does not attack the bond pad material or under-bump metallization layers, and creates no new mechanisms for open circuits

Neuropeptide Y concentrations in cerebrospinal fluid are unchanged in obesity

Neuropeptide Y (NPy) is a potent centrally acting appetite-stimulating peptide implicated in the regulation of energy balance. It induces hyperphagia and obesity when injected into the rat hypothalamus. Hypothalamic NPY and NPY mRNA levels are increased in spontaneously obese rats, suggesting that it may be involved in causing obesity in rodents. It is not known whether NPY has a role in the pathogenesis of obesity in man. NPY is found in human cerebrospinal fluid (CSF) and we have therefore compared CSF NPY levels in normal obese and non-obese individuals to determine whether NPY concentrations might be increased in obesity. We studied 25 clinically normal subjects (age 67 ± 5 years. male 11. female 14) undergoing spinal anaesthesia. None had any significant illness. Samples of 1 ml were freeze-dried and reconstituted to 100 ul and 35ul aliquots were assayed for NPY using an in-house RIA. CSF NPY levels were not correlated with body mass index (BMI) (r=O.088. p=O.673) and there were no differences in NPY concentrations between groups of subjects stratified for BMI: BMI 25 (n=ll), 702 ± 55 fmol/ml (differences between all groups. p>0l). CSF NPY levels are therefore not increased in human obesity. NPY is found in many brain regions outside the hypothalamic appetite-regulating nuclei, which could contribute to CSF levels. This negative observation does not therefore exclude a role of the peptide, acting specifically in the hypothalamus, in contributing to human obesity

Myeloid Wnt ligands are required for normal development of dermal lymphatic vasculature

Resident tissue myeloid cells play a role in many aspects of physiology including development of the vascular systems. In the blood vasculature, myeloid cells use VEGFC to promote angiogenesis and can use Wnt ligands to control vascular branching and to promote vascular regression. Here we show that myeloid cells also regulate development of the dermal lymphatic vasculature using Wnt ligands. Using myeloid-specific deletion of the WNT transporter Wntless we show that myeloid Wnt ligands are active at two distinct stages of development of the dermal lymphatics. As lymphatic progenitors are emigrating from the cardinal vein and intersomitic vessels, myeloid Wnt ligands regulate both their numbers and migration distance. Later in lymphatic development, myeloid Wnt ligands regulate proliferation of lymphatic endothelial cells (LEC) and thus control lymphatic vessel caliber. Myeloid-specific deletion of WNT co-receptor Lrp5 or Wnt5a gain-of-function also produce elevated caliber in dermal lymphatic capillaries. These data thus suggest that myeloid cells produce Wnt ligands to regulate lymphatic development and use Wnt pathway co-receptors to regulate the balance of Wnt ligand activity during the macrophage-LEC interaction