Effect of high pressure on multiferroic BiFeO3

We report experimental evidence for pressure instabilities in the model multiferroic BiFeO3 and namely reveal two structural phase transitions around 3 GPa and 10 GPa by using diffraction and far-infrared spectroscopy at a synchrotron source. The intermediate phase from 3 to 9 GPa crystallizes in a monoclinic space group, with octahedra tilts and small cation displacements. When the pressure is further increased the cation displacements (and thus the polar character) of BiFeO3 is suppressed above 10 GPa. The above 10 GPa observed non-polar orthorhombic Pnma structure is in agreement with recent theoretical ab-initio prediction, while the intermediate monoclinic phase was not predicted theoretically.Comment: new version, accepted for publication in Phys. Rev.

Non-equilibrium Casimir forces: Spheres and sphere-plate

We discuss non-equilibrium extensions of the Casimir force (due to electromagnetic fluctuations), where the objects as well as the environment are held at different temperatures. While the formalism we develop is quite general, we focus on a sphere in front of a plate, as well as two spheres, when the radius is small compared to separation and thermal wavelengths. In this limit the forces can be expressed analytically in terms of the lowest order multipoles, and corroborated with results obtained by diluting parallel plates of vanishing thickness. Non-equilibrium forces are generally stronger than their equilibrium counterpart, and may oscillate with separation (at a scale set by material resonances). For both geometries we obtain stable points of zero net force, while two spheres may have equal forces in magnitude and direction resulting in a self-propelling state.Comment: 6 pages, 6 figure

Reducing postnatal depression, anxiety and stress using an infant sleep intervention

Extent: 6p.Objective: To examine the psychological well-being of mothers following participation in a behavioural modification programme previously shown to improve infant sleep. Design, setting and participants: A 45 min consultation with either a general practitioner (GP) or trained nurse providing verbal and written information describing sleep physiology in infants and strategies to improve infant sleep. Eighty mothers of infants 6−12 months of age with established infant sleep problems at a single general practice, Adelaide, South Australia. Main outcome measures: The Depression Anxiety Stress Scale 21 (DASS21) immediately prior to the first consultation and again at follow-up approximately 3 weeks later. The number of infant nocturnal awakenings requiring parental support was also reported by mothers on both occasions. Results: All measures of maternal well-being and infant nocturnal awakenings improved significantly. The mean number of maximum nocturnal awakenings decreased from 5.0 to 0.5 (mean difference 4.4, 95% CI 3.4 to 5.5). All measures of DASS21 improved significantly. The mean total DASS21 decreased from 29.1 to 14.9 (mean decrease 14.2, 95% CI 10.2 to 18.2); mean depression decreased from 7.9 to 2.8 (mean difference 5.2, 95% CI 3.7 to 6.7); mean anxiety decreased from 4.6 to 2.6 (mean difference 2.0, 95% CI 0.7 to 3.2); mean stress decreased from 16.6 to 9.5 (mean difference 7.0, 95% CI 5.1 to 9.0). The proportion of mothers assessed as having any degree of depression decreased by 85% from 26/80 (32.5%) to 4/80 (5%). Conclusions: The number of nocturnal awakenings requiring parental support among infants aged 6−12 months significantly decreased following a single consultation on infant sleep physiology and teaching behavioural strategies to improve sleep. Significant improvements in maternal stress, anxiety and depression were also observed.Brian Symon, Michael Bammann, Georgina Crichton, Chris Lowings, James Tucso

Trace formulae for non-equilibrium Casimir interactions, heat radiation and heat transfer for arbitrary objects

We present a detailed derivation of heat radiation, heat transfer and (Casimir) interactions for N arbitrary objects in the framework of fluctuational electrodynamics in thermal non-equilibrium. The results can be expressed as basis-independent trace formulae in terms of the scattering operators of the individual objects. We prove that heat radiation of a single object is positive, and that heat transfer (for two arbitrary passive objects) is from the hotter to a colder body. The heat transferred is also symmetric, exactly reversed if the two temperatures are exchanged. Introducing partial wave-expansions, we transform the results for radiation, transfer and forces into traces of matrices that can be evaluated in any basis, analogous to the equilibrium Casimir force. The method is illustrated by (re)deriving the heat radiation of a plate, a sphere and a cylinder. We analyze the radiation of a sphere for different materials, emphasizing that a simplification often employed for metallic nano-spheres is typically invalid. We derive asymptotic formulae for heat transfer and non-equilibrium interactions for the cases of a sphere in front a plate and for two spheres, extending previous results. As an example, we show that a hot nano-sphere can levitate above a plate with the repulsive non-equilibrium force overcoming gravity -- an effect that is not due to radiation pressure.Comment: 29 pages, 6 figures (v2: Sentence added in Sec. 1

Improving obstetric care in low-resource settings: implementation of facility-based maternal death reviews in five pilot hospitals in Senegal

<p>Abstract</p> <p>Background</p> <p>In sub-Saharan Africa, maternal and perinatal mortality and morbidity are major problems. Service availability and quality of care in health facilities are heterogeneous and most often inadequate. In resource-poor settings, the facility-based maternal death review or audit is one of the most promising strategies to improve health service performance. We aim to explore and describe health workers' perceptions of facility-based maternal death reviews and to identify barriers to and facilitators of the implementation of this approach in pilot health facilities of Senegal.</p> <p>Methods</p> <p>This study was conducted in five reference hospitals in Senegal with different characteristics. Data were collected from focus group discussions, participant observations of audit meetings, audit documents and interviews with the staff of the maternity unit. Data were analysed by means of both quantitative and qualitative approaches.</p> <p>Results</p> <p>Health professionals and service administrators were receptive and adhered relatively well to the process and the results of the audits, although some considered the situation destabilizing or even threatening. The main barriers to the implementation of maternal deaths reviews were: (1) bad quality of information in medical files; (2) non-participation of the head of department in the audit meetings; (3) lack of feedback to the staff who did not attend the audit meetings. The main facilitators were: (1) high level of professional qualifications or experience of the data collector; (2) involvement of the head of the maternity unit, acting as a moderator during the audit meetings; (3) participation of managers in the audit session to plan appropriate and realistic actions to prevent other maternal deaths.</p> <p>Conclusion</p> <p>The identification of the barriers to and the facilitators of the implementation of maternal death reviews is an essential step for the future adaptation of this method in countries with few resources. We recommend for future implementation of this method a prior enhancement of the perinatal information system and initial training of the members of the audit committee – particularly the data collector and the head of the maternity unit. Local leadership is essential to promote, initiate and monitor the audit process in the health facilities.</p

From tacit knowledge to visual expertise: Eye-tracking support in maritime education and training

The maritime pilot is an expert with knowledge on a specific navi- gational route. The maritime pilot cadet undergoes maritime education and training in classrooms, onboard vessels and in simulators. Developing visual expertise is a basic objective. Transferring knowledge from experienced mar- itime pilots to maritime pilot cadets is challenging since some of this knowledge is tacit. The transference is achieved by externalization and socialization pro- cesses. The objective of this pre-study was to assess eye-tracking methodology as a tool to support maritime education and training, and for transferring tacit knowledge. The study was performed in an explorative way during simulator sessions, by interviews, questionnaires and observations. The result shows that eye-tracking methodology is useful for transferring tacit knowledge in simulator settings, but not during other parts of the education and training. The results also show that situational awareness of maritime pilot instructors and maritime pilot cadets increases when utilizing eye-tracking methodology

High-temperature and high-pressure behavior of carbonates in the ternary diagram CaCO3-MgCO3-FeCO3

We report the thermal expansion and the compressibility of carbonates in the ternary compositional diagram CaCO3-MgCO3-FeCO3, determined by in situ X-ray powder and single-crystal diffraction. High-temperature experiments were performed by high-resolution X-ray synchrotron powder diffraction from ambient to decarbonation temperatures (25-850 \ub0C). Single-crystal synchrotron X ray diffraction experiments were performed in a variable pressure range (0-100 GPa), depending on the stability field of the rhombohedral structure at ambient temperature, which is a function of the carbonate composition. The thermal expansion increases from calcite, CaCO3, \u3b10 = 4.10(7) 710-5 K-1, to magnesite, MgCO3, \u3b10 = 7.04(2) 710-5 K-1. In the magnesite-siderite (FeCO3) join, the thermal expansion decreases as iron content increases, with an experimental value of \u3b10 = 6.44(4) 710-5 K-1 for siderite. The compressibility in the ternary join is higher (i.e., lower bulk modulus) in calcite and Mg-calcite [K0 = 77(3) GPa for Ca0.91Mg0.06Fe0.03(CO3)] than in magnesite, K0 = 113(1) GPa, and siderite, K0 = 125(1) GPa. The analysis of thermal expansion and compressibility variation in calcite-magnesite and calcite-iron-magnesite joins clearly shows that the structural changes associated to the order-disorder transitions [i.e., R3c calcite-type structure vs. R3 CaMg(CO3)2 dolomite-type structure] do not affect significantly the thermal expansion and compressibility of carbonate. On the contrary, the chemical compositions of carbonates play a major role on their thermo-elastic properties. Finally, we use our P-V-T equation of state data to calculate the unit-cell volume of a natural ternary carbonate, and we compare the calculated volumes to experimental observations, measured in situ at elevated pressure and temperatures, using a multi-anvil device. The experimental and calculated data are in good agreement demonstrating that the equation of state here reported can describe the volume behavior with the accuracy needed, for example, for a direct chemical estimation of carbonates based on experimental unit-cell volume data of carbonates at high pressures and temperatures

Advanced liver disease in Russian children and adolescents with chronic hepatitis C

Russia has one of the highest prevalences of paediatric chronic hepatitis C infection (CHC). Our aim was to provide a detailed characterization of children and adolescents with CHC including treatment outcomes.Thus, an observational study of children with CHC aged <18 years was conducted in three hepatology centres from November 2014 to May 2017. Of 301 children(52% male), 196(65%) acquired HCV vertically, 70(23%) had a history of blood transfusion or invasive procedures, 1 injecting drug use and 34(11%) had no known risk factors. Median age at HCV diagnosis was 3.1[IQR 1.1,8.2] and 10.8[7.4,14.7] at last follow-up. The most common genotype was 1b(51%), followed by 3(31%). Over a quarter of patients (84,28%) had raised liver transaminases. Of 92 with liver biopsy, 38(41%) had bridging fibrosis (median age 10.4[7.1,14.1]). Of 223 evaluated by transient elastography (TE), 67(30%) had liver stiffness ≥5.0kPa. For each year increase in age mean stiffness increased by 0.09kPa(95%CI 0.05,0.13, p<0.001). There was significant correlation between liver stiffness and biopsy results (Tau-b=0.29, p=0.042). Of 205 treated with IFN-based regimens, 100(49%) had SVR24. Most children (191,93%) experienced adverse reactions, leading to treatment discontinuation in 6(3%). In conclusion, a third of children acquired HCV via non-vertical routes and a substantial proportion of those with liver biopsy had advanced liver disease. Only half of children achieved SVR24 with IFN-based regimens highlighting the need for more effective and better tolerated treatments with direct-acting antivirals. Further studies are warranted in Russia on causes and prevention of non-vertical transmission of HCV in children. This article is protected by copyright. All rights reserved

The landscape of selection in 551 esophageal adenocarcinomas defines genomic biomarkers for the clinic.

Esophageal adenocarcinoma (EAC) is a poor-prognosis cancer type with rapidly rising incidence. Understanding of the genetic events driving EAC development is limited, and there are few molecular biomarkers for prognostication or therapeutics. Using a cohort of 551 genomically characterized EACs with matched RNA sequencing data, we discovered 77 EAC driver genes and 21 noncoding driver elements. We identified a mean of 4.4 driver events per tumor, which were derived more commonly from mutations than copy number alterations, and compared the prevelence of these mutations to the exome-wide mutational excess calculated using non-synonymous to synonymous mutation ratios (dN/dS). We observed mutual exclusivity or co-occurrence of events within and between several dysregulated EAC pathways, a result suggestive of strong functional relationships. Indicators of poor prognosis (SMAD4 and GATA4) were verified in independent cohorts with significant predictive value. Over 50% of EACs contained sensitizing events for CDK4 and CDK6 inhibitors, which were highly correlated with clinically relevant sensitivity in a panel of EAC cell lines and organoids.OCCAMS was funded by a Programme Grant from Cancer Research UK (RG66287), and the laboratory of R.C.F. is funded by a Core Programme Grant from the Medical Research Council. We thank the Human Research Tissue Bank, which is supported by the UK National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre, from Addenbrooke’s Hospital. Additional infrastructure support was provided from the Cancer Research UK–funded Experimental Cancer Medicine Centre

A pragmatic cluster randomised trial evaluating three implementation interventions

Background Implementation research is concerned with bridging the gap between evidence and practice through the study of methods to promote the uptake of research into routine practice. Good quality evidence has been summarised into guideline recommendations to show that peri-operative fasting times could be considerably shorter than patients currently experience. The objective of this trial was to evaluate the effectiveness of three strategies for the implementation of recommendations about peri-operative fasting. Methods A pragmatic cluster randomised trial underpinned by the PARIHS framework was conducted during 2006 to 2009 with a national sample of UK hospitals using time series with mixed methods process evaluation and cost analysis. Hospitals were randomised to one of three interventions: standard dissemination (SD) of a guideline package, SD plus a web-based resource championed by an opinion leader, and SD plus plan-do-study-act (PDSA). The primary outcome was duration of fluid fast prior to induction of anaesthesia. Secondary outcomes included duration of food fast, patients' experiences, and stakeholders' experiences of implementation, including influences. ANOVA was used to test differences over time and interventions. Results Nineteen acute NHS hospitals participated. Across timepoints, 3,505 duration of fasting observations were recorded. No significant effect of the interventions was observed for either fluid or food fasting times. The effect size was 0.33 for the web-based intervention compared to SD alone for the change in fluid fasting and was 0.12 for PDSA compared to SD alone. The process evaluation showed different types of impact, including changes to practices, policies, and attitudes. A rich picture of the implementation challenges emerged, including inter-professional tensions and a lack of clarity for decision-making authority and responsibility. Conclusions This was a large, complex study and one of the first national randomised controlled trials conducted within acute care in implementation research. The evidence base for fasting practice was accepted by those participating in this study and the messages from it simple; however, implementation and practical challenges influenced the interventions' impact. A set of conditions for implementation emerges from the findings of this study, which are presented as theoretically transferable propositions that have international relevance. Trial registration ISRCTN18046709 - Peri-operative Implementation Study Evaluation (POISE