Solubilities of pyrene in organic solvents: Comparison between chemical potential calculations using a cavity-based method and direct coexistence simulations

In this paper, we benchmark a cavity-based simulation method for calculating the relative solubility of large molecules in explicit solvents. The essence of the procedure is the accounting of the Gibbs energy change associated with an alchemical thermodynamic cycle where, in sequence, a cavity is created in a solvent, a solute is inserted in the cavity and the cavity is annihilated. The Gibbs energy change is equated to the excess chemical potential allowing the comparison of solubilities in different solvents. The results obtained using the cavity-based method are compared to direct large-scale molecular dynamics simulations performed using coarse-grained models for calculating the partition coefficient of pyrene between heptane and toluene. We demonstrate the applicability of this cavity-based technique under high pressure/temperature conditions.The authors gratefully acknowledge the generous funding and technical support for this work from BP Plc through the International Centre for Advanced Materials (ICAM) which made this research possible

Water-mediated epoxy/surface adhesion: Understanding the interphase region

This is the final version. Available on open access from Wiley via the DOI in this record. Data Availability Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.Epoxy resins coatings are commonly found in corrosion protection coatings but the presence of water can affect their adhesion to the substrate, often weakening the adhesion of the coating to the solid, reducing its efficiency. Nevertheless, small amounts of water can enhance the epoxy/substrate interactions. In this work, the interphase region of an epoxy precursor and metal oxide substrates is investigated using molecular simulations and it is found that water accumulates between the epoxy layer and the solid substrate. At high water concentrations (9%wt) the interaction between the epoxy precursor and the solid surface is weakened regardless of the nature of the solid, but at low water concentrations the nature of the solid surface becomes important. For hematite, the presence of water decreases the strength of adhesion but for goethite the presence of a small amount of water (3%wt) enhances the adhesion to the surface resulting in a densification at the interface.Engineering and Physical Sciences Research Council (EPSRC

The effect of cross-linker structure on interfacial interactions, polymer dynamics and network composition in an epoxy-amine resin

This is the final version. Available from Elsevier via the DOI in this record. Data availability: Data will be made available on request.Understanding interactions at the polymer / metal oxide interface is central to improving the performance lifetime of corrosion resistant coatings, where network polymers commonly form via step growth mechanisms in the presence of pigments. Here we employ a holistic analytical approach encompassing ATR-FTIR, DSC and molecular dynamics simulations to consider how crosslinker structure affects adsorption and incorporation into the network, using a stoichiometric mixture of diglycidylether of bisphenol-A (DGEBA) with m-xylylenediamine (MXDA) cured in the presence of hematite (Fe2O3) and goethite (FeOOH) powders. We find that the rigid MXDA molecule has two distinct binding modes on both hematite and goethite, and that synergistic hydrogen bonding modes observed on goethite limit interconversion between the two. Moreover, we find that binding persists in fully cured composite samples, determining the levels of residual amine. In contrast to previously reported results using triethylenetetramine (TETA) crosslinkers, however, we find that the Tg of composite specimens is independent of added hematite and goethite volumes. Molecular dynamics simulations demonstrate this is due to electrostatic binding between the cationic Fe sites and electronegative heteroatoms in MXDA. This renders both amine functionalities unavailable for incorporation into the network and hence, unlike TETA, MXDA adsorption does not determine polymer dynamics.Engineering and Physical Sciences Research CouncilAkzoNobe

Exercise augmentation compared to usual care for Post Traumatic Stress Disorder: A Randomised Controlled Trial (The REAP study: Randomised Exercise Augmentation for PTSD)

<p>Abstract</p> <p>Background</p> <p>The physical wellbeing of people with mental health conditions can often be overlooked in order to treat the primary mental health condition as a priority. Exercise however, can potentially improve both the primary psychiatric condition as well as physical measures that indicate risk of other conditions such as diabetes mellitus and cardiovascular disease. Evidence supports the role of exercise as an important component of treatment for depression and anxiety, yet no randomised controlled trials (RCT's) have been conducted to evaluate the use of exercise in the treatment of people with post traumatic stress disorder (PTSD).</p> <p>This RCT will investigate the effects of structured, progressive exercise on PTSD symptoms, functional ability, body composition, physical activity levels, sleep patterns and medication usage.</p> <p>Methods and design</p> <p>Eighty participants with a Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) diagnosis of PTSD will be recruited. Participants will have no contraindications to exercise and will be cognitively able to provide consent to participate in the study.</p> <p>The primary outcome measures will be PTSD symptoms, measured through the PTSD Checklist Civilian (PCL-C) scale. Secondary outcome measures will assess depression and anxiety, mobility and strength, body composition, physical activity levels, sleep patterns and medication usage. All outcomes will be assessed by a health or exercise professional masked to group allocation at baseline and 12 weeks after randomisation.</p> <p>The intervention will be a 12 week individualised program, primarily involving resistance exercises with the use of exercise bands. A walking component will also be incorporated. Participants will complete one supervised session per week, and will be asked to perform at least two other non-supervised exercise sessions per week. Both intervention and control groups will receive all usual non-exercise interventions including psychotherapy, pharmaceutical interventions and group therapy.</p> <p>Discussion</p> <p>This study will determine the effect of an individualised and progressive exercise intervention on PTSD symptoms, depression and anxiety, mobility and strength, body composition, physical activity levels, sleep patterns and medication usage among people with a DSM-IV diagnosis of PTSD.</p> <p>Trial Registration</p> <p><a href="http://www.anzctr.org.au/ACTRN12605000567628.aspx">ACTRN12610000579099</a></p

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Understanding noncompliance with selective donor deferral criteria for high-risk behaviors in Australian blood donors

Using a predonation screening questionnaire, potential blood donors are screened for medical or behavioral factors associated with an increased risk for transfusion-transmissible infection. After disclosure of these risks, potential donors are deferred from donating. Understanding the degree of failure to disclose full and truthful information (termed noncompliance) is important to determine and minimize residual risk. This study estimates the prevalence of, and likely reasons for, noncompliance among Australian donors with the deferrals for injecting drug use, sex with an injecting drug user, male-to-male sex, sex worker activity or contact, and sex with a partner from a high-HIV-prevalence country. Study Design and Methods An anonymous, online survey of a nationally representative sample of Australian blood donors was conducted. Prevalence of noncompliance with deferrable risk categories was estimated. Factors associated with noncompliance were determined using unadjusted and adjusted odds ratios. Results Of 98,044 invited donors, 30,790 donors completed the survey. The estimated prevalence of overall noncompliance (i.e., to at least one screening question) was 1.65% (95% confidence interval CI, 1.51%-1.8%). Noncompliance with individual deferrals ranged from 0.05% (sex work) to 0.54% (sex with an injecting drug user). The prevalences of the disclosed exclusionary risk behaviors were three to 14 times lower than their estimated prevalence in the general population. Conclusion The prevalence of noncompliance is relatively low but our estimate is likely to be a lower bound. The selected high-risk behaviors were substantially less common in blood donors compared to the general population suggesting that self-deferral is effective. Nevertheless, a focus on further minimization should improve the blood safety. © 2014 AABB