Classical density functional theory & simulations on a coarse-grained model of aromatic ionic liquids.

A new classical density functional approach is developed to accurately treat a coarse-grained model of room temperature aromatic ionic liquids. Our major innovation is the introduction of charge-charge correlations, which are treated in a simple phenomenological way. We test this theory on a generic coarse-grained model for aromatic RTILs with oligomeric forms for both cations and anions, approximating 1-alkyl-3-methyl imidazoliums and BF4(-), respectively. We find that predictions by the new density functional theory for fluid structures at charged surfaces are very accurate, as compared with molecular dynamics simulations, across a range of surface charge densities and lengths of the alkyl chain. Predictions of interactions between charged surfaces are also presented

Rate of comorbidities in giant cell arteritis : A population-based study

Objective. To compare the rate of occurrence of comorbidities, including severe infections, in a population-based cohort of patients with biopsy-proven giant cell arteritis (GCA) with a reference population in Southern Sweden. Methods. The study included a population-based cohort of biopsy-proven GCA cases diagnosed between 1998 and 2010 from the Skane region in Southern Sweden (population: 1.2 million). For each patient, 4 reference subjects were identified from the general population and matched for age, sex, area of residence, and date of diagnosis of GCA. Using the Skane Healthcare Register, comorbidities and severe infections (requiring hospitalization) diagnosed after GCA onset were identified. The rate of the first occurrence of each comorbidity was the result of dividing the number of subjects with a given comorbidity by the person-years of followup. The rate ratio (RR; GCA:reference population) was also calculated. Results. There were 768 patients (571 women) with GCA and 3066 reference persons included in the study. The RR were significantly elevated for osteoporosis (2.81, 95% CI 2.33-3.37), followed by venous thromboembolic diseases (2.36, 95% CI 1.61-3.40), severe infections (1.85, 95% CI 1.57-2.18), thyroid diseases (1.55, 95% CI 1.25-1.91), cerebrovascular accidents (1.40, 95% CI 1.12-1.74), and diabetes mellitus (1.29, 95% CI 1.05-1.56). The RR for ischemic heart disease was elevated, but did not reach statistical significance (1.20, 95% CI 1.00-1.44). Conclusion. Patients with GCA have higher rates of selected comorbidities, including severe infections, compared with a reference population. Several of these comorbidities may be related to treatment with glucocorticosteroids, emphasizing the unmet need to find alternative treatments for GCA

Fused coarse-grained model of aromatic ionic liquids and their behaviour at electrodes.

A fused coarse-grained model of aromatic ionic liquids 1-alkyl-3-methylimidazoliums tetrafluoroborate ([CnMIM(+)][BF4(-)]) has been constructed. Structural and dynamical properties calculated from our model are compared with experimental data as well as with corresponding results from simulations of other suggested models. Specifically, we adopt a fused-sphere coarse-grained model for cations and anions. This model is utilized to study structure and differential capacitance in models of flat and porous carbon electrodes. We find that the capacitance varies with pore size, in a manner that is related to the packing of ions inside the pore. For very narrow pores, diffusion is slow and the establishment of thermodynamic equilibrium may exceed the practical limits for our molecular dynamics simulations

Theoretical predictions of structures in dispersions containing charged colloidal particles and non-adsorbing polymers

We develop a theoretical model to describe structural effects on a specific system of charged colloidal polystyrene particles, upon the addition of non-adsorbing PEG polymers. This system has previously been investigated experimentally, by scattering methods, so we are able to quantitatively compare predicted structure factors with corresponding experimental data. Our aim is to construct a model that is coarse-grained enough to be computationally manageable, yet detailed enough to capture the important physics. To this end, we utilize classical polymer density functional theory, wherein all possible polymer configurations are accounted for, subject to a mean-field Boltzmann weight. We make efforts to counteract drawbacks with this mean-field approach, resulting in structural predictions that agree very well with computationally more demanding simulations. Electrostatic interactions are handled at the fully non-linear Poisson-Boltzmann level, and we demonstrate that a linearization leads to less accurate predictions. The particle charge is an experimentally unknown parameter. We define the surface charge such that the experimental and theoretical gel point at equal polymer concentration coincide. Assuming a fixed surface charge for a certain salt concentration, we find very good agreements between measured and predicted structure factors across a wide range of polymer concentrations. We also present predictions for other structural quantities, such as radial distribution functions, and cluster size distributions. Finally, we demonstrate that our model predicts the occurrence of equilibrium clusters at high polymer concentrations, but low particle volume fractions and salt levels

EQ-5D utility, response and drug survival in rheumatoid arthritis patients on biologic monotherapy:A prospective observational study of patients registered in the south Swedish SSATG registry

Objectives Biologic agents have dramatically changed treatment of rheumatoid arthritis (RA). To date only scarce head-To-head data exist especially when the biological therapies are given as monotherapy without concomitant disease modifying drugs (DMARDs). Thus the objective of the current study is to evaluate treatment response of all available biological therapies with special focus on utility (EQ-5D-3L) and drug survival of biologic DMARDs (bDMARDs) prescribed as monotherapy in RA patients in southern Sweden. Materials and methods All RA patients registered in a regional database as initiating bDMARD as monotherapy, i.e. without concomitant conventional synthetic DMARDs (csDMARDs), from 1st of January 2006 through 31st of December 2012, were included. Patients were followed from initiation of the first dose of bDMARD monotherapy treatment until withdrawal from treatment, loss of follow-up or 31st of December 2012. Descriptive statistics for utility (EQ-5D-3L), effectiveness, and drug survival of bDMARD monotherapy were calculated. Results During the study period, a total of 554 patients were registered in SSATG as initiating bDMARD monotherapy. Most of the patients were women (81%), with a mean age of 57 years. The average disease duration was more than 12 years, and on average the patients had previously been treated with approximately four different csDMARDs. Fifty-five percent of the patients were initiating their first bDMARD, 26% their second, and 19% their third or more. At baseline the average EQ-5D-3L was 0.34. Most patients had moderate to high disease activity, with a mean DAS28 of 5.0, and were substantially disabled, with an average HAQ score of 1.4. At 6 months follow-up, the EQ-5D-3L in patients still on the biologic drug had increased by mean 0.23 (SD 0.4) with no differences between type of bDMARD (p = 0.49). The mean change in EQ-5D-3L ranged from 0.11 (rituximab and infliximab) to 0.42 (tocilizumab). Although the changes were numerically different, no distinct pattern favored any particular bDMARD for EQ-5D-3L (p = 0.49) or other clinical outcomes. Overall, DAS28 defined remission and low disease activity were achieved in 20% and 43% of patients, respectively. Drug survival rates were statistically significantly different between bDMARDs (p = 0.01), with the highest rates observed for rituximab, followed by etanercept. After failing first course of anti-TNF, patients switching to another mode of action had significantly higher drug survival than those switching to a second course of anti-TNF therapy (p = 0.02). Conclusions Utility (EQ-5D-3L) increased after 6 months of all bDMARD treatments in monotherapy, indicating improvement of patients' quality of life. After failure of anti-TNF treatment in monotherapy, switching to another mode of action may be associated with better drug survival than starting a second TNF-inhibitor

Animal escapology I: theoretical issues and emerging trends in escape trajectories

Escape responses are used by many animal species as their main defence against predator attacks. Escape success is determined by a number of variables; important are the directionality (the percentage of responses directed away from the threat) and the escape trajectories (ETs) measured relative to the threat. Although logic would suggest that animals should always turn away from a predator, work on various species shows that these away responses occur only approximately 50–90% of the time. A small proportion of towards responses may introduce some unpredictability and may be an adaptive feature of the escape system. Similar issues apply to ETs. Theoretically, an optimal ET can be modelled on the geometry of predator–prey encounters. However, unpredictability (and hence high variability) in trajectories may be necessary for preventing predators from learning a simple escape pattern. This review discusses the emerging trends in escape trajectories, as well as the modulating key factors, such as the surroundings and body design. The main ET patterns identified are: (1) high ET variability within a limited angular sector (mainly 90–180deg away from the threat; this variability is in some cases based on multiple peaks of ETs), (2) ETs that allow sensory tracking of the threat and (3) ETs towards a shelter. These characteristic features are observed across various taxa and, therefore, their expression may be mainly related to taxon-independent animal design features and to the environmental context in which prey live – for example whether the immediate surroundings of the prey provide potential refuges

Variable response of three Trifolium repens ecotypes to soil flooding by seawater.

BACKGROUND AND AIMS: Despite concerns about the impact of rising sea levels and storm surge events on coastal ecosystems, there is remarkably little information on the response of terrestrial coastal plant species to seawater inundation. The aim of this study was to elucidate responses of a glycophyte (white clover, Trifolium repens) to short-duration soil flooding by seawater and recovery following leaching of salts. METHODS: Using plants cultivated from parent ecotypes collected from a natural soil salinity gradient, the impact of short-duration seawater soil flooding (8 or 24 h) on short-term changes in leaf salt ion and organic solute concentrations was examined, together with longer term impacts on plant growth (stolon elongation) and flowering. KEY RESULTS: There was substantial Cl(-) and Na(+) accumulation in leaves, especially for plants subjected to 24 h soil flooding with seawater, but no consistent variation linked to parent plant provenance. Proline and sucrose concentrations also increased in plants following seawater flooding of the soil. Plant growth and flowering were reduced by longer soil immersion times (seawater flooding followed by drainage and freshwater inputs), but plants originating from more saline soil responded less negatively than those from lower salinity soil. CONCLUSIONS: The accumulation of proline and sucrose indicates a potential for solute accumulation as a response to the osmotic imbalance caused by salt ions, while variation in growth and flowering responses between ecotypes points to a natural adaptive capacity for tolerance of short-duration seawater soil flooding in T. repens. Consequently, it is suggested that selection for tolerant ecotypes is possible should the predicted increase in frequency of storm surge flooding events occur