The microstructure and surface morphology of radiopaque tricalcium silicate cement exposed to different curing conditions

Objective. Tricalcium silicate is the major constituent phase in mineral trioxide aggregate (MTA). It is thus postulated that pure tricalcium silicate can replace the Portland cement component of MTA. The aim of this research was to evaluate the microstructure and surface characteristics of radiopaque tricalcium silicate cement exposed to different curing conditions namely at 100% humidity or immersed in either water or a simulated body fluid at 37 ◦C. Methods. The materials under study included tricalcium silicate and Portland cements with and without the addition of bismuth oxide radiopacifier. Material characterization was performed on hydrated cements using a combination of scanning electron microscopy (SEM) with X-ray energy dispersive (EDX) analyses and X-ray diffraction (XRD) analyses. Surface morphology was further investigated using optical profilometry. Testing was performed on cements cured at 100% humidity or immersed in either water or Hank’s balanced salt solution (HBSS) for 1 and 28 days at 37 ◦C. In addition leachate analysis was performed by X-ray fluorescence of the storage solution. The pH of the storage solution was assessed. Results. All the cements produced calcium silicate hydrate and calcium hydroxide on hydration. Tricalcium silicate showed a higher reaction rate than Portland cement and addition of bismuth oxide seemed to also increase the rate of reaction with more calcium silicate hydrate and calcium hydroxide being produced as demonstrated by SEM and XRD analysis and also by surface deposits viewed by the optical profilometer. Cement immersion in HBSS resulted in the deposition of calcium phosphate during the early stages following immersion and extensive calcification after 28 days. The pH of all storage solutions was alkaline. The immersion in distilled water resulted in a higher pH of the solution than when the cements were immersed in HBSS. Leachate analysis demonstrated high calcium levels in all cements tested with higher levels in tricalcium silicate and bismuth replaced cements. Significance. Tricalcium silicate cement is more bioactive than Portland cement as demonstrated by various characterization techniques. The bioactivity was monitored by measuring the production of calcium hydroxide and the formation of calcium phosphate when in contact with simulated body fluids.peer-reviewe

An integrated mid-range theory of postpartum family development: a guide for research and practice.

AIM: This paper is a report of a study to identify parents' perceptions of postpartum family experiences. BACKGROUND: There is a growing worldwide emphasis on family support. Government policy in the United Kingdom advocates a family-centred approach in which a core universal postbirth service is offered to all families with additional support for parents of children with complex needs. Health visitors provide family postpartum care without an agreed theory directing or standardizing practice. There is a need to identify parental experiences to define family-centred care. METHOD: A qualitative, exploratory approach was undertaken using a purposive sample of 17 postpartum families. Data were collected in one region of Northern Ireland in 2001-2002. Participants' experiences and views were accessed during two focus groups with a total of seven participants, and six in-depth interviews. Thematic analysis was conducted. FINDINGS: One core theme, 'thriving and surviving', and three main themes, 'baby nurture', 'life changes', 'coping and adapting resources', were identified to describe how parents developed during the first 8-week postpartum. These were influenced by the physical, the psychosocial and the environmental factors. The identified themes were mapped together to form an Integrated Mid-Range Theory of Postpartum Parent Development. CONCLUSION: As parents need to negotiate successfully both present coping and future development during the postpartum period, there is a need for professionals to offer services that are orientated to holistic short- and long-term well-being. The findings, further to additional research, may be used by health visitors and other professionals to direct universal postpartum care

Examining the transfer of soils to clothing materials: Implications for forensic investigations

Soil forensics has proven instrumental in assisting criminal investigation, and there is an increasing demand for experimental studies on such trace evidence. Here we present the first detailed study on the influence of clothing materials on soil transfer. We adopt an experimental approach to test the transfer of five common UK soils to five different clothing materials. Our experiment is designed to represent victim or perpetrator contact with soil at the scene of a crime. We highlight the complex relationship between soil transfer and clothing material type. Whilst over half of our soils tested displayed differential transfer to different clothing materials, soil moisture content and soil type were found to have a greater influence on the transfer of soils overall. Soil transfer is typically more effective across all material types when soils are wet and saturated. However, we find the relationship between soil transfer and material type to be more complex when soils are dry, with a significant bias in soil transfer to fleece material, which we attribute to static attraction. Encouragingly, for the analysis of forensic soils recovered from clothing artefacts, each of the transfer experiments we conducted led to soil transfer to every tested material. We suggest that future empirical studies now focus on the persistence of soils over time to clothing materials after transfer has occurred, and the transfer and persistence of soil palynomorphs present within soils

Training future generations to deliver evidence-based conservation and ecosystem management

1. To be effective, the next generation of conservation practitioners and managers need to be critical thinkers with a deep understanding of how to make evidence-based decisions and of the value of evidence synthesis. 2. If, as educators, we do not make these priorities a core part of what we teach, we are failing to prepare our students to make an effective contribution to conservation practice. 3. To help overcome this problem we have created open access online teaching materials in multiple languages that are stored in Applied Ecology Resources. So far, 117 educators from 23 countries have acknowledged the importance of this and are already teaching or about to teach skills in appraising or using evidence in conservation decision-making. This includes 145 undergraduate, postgraduate or professional development courses. 4. We call for wider teaching of the tools and skills that facilitate evidence-based conservation and also suggest that providing online teaching materials in multiple languages could be beneficial for improving global understanding of other subject areas.Peer reviewe

Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology

notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations

Magnetic resonance studies of adsorbed molecules in zeolites

SIGLEAvailable from British Library Document Supply Centre- DSC:D175467 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

An X-ray diffraction and MAS NMR study of the thermal expansion properties of calcined siliceous ferrierite

Powder and single-crystal X-ray diffraction, combined with MAS NMR measurements, has been used to study the thermal expansion of siliceous zeolite ferrierite as it approaches a second-order displacive phase transition from a low-symmetry (Pnnm) to a high-symmetry (Immm) structure. Below the transition temperature, ferrierite exhibits positive thermal expansivity. However, above the transition temperature a significant change in thermal behavior is seen, and ferrierite becomes a negative thermal expansion material. Accurate variable-temperature single-crystal X-ray diffraction measurements confirm the transition temperature and allow the changes in average atomic position to be followed with temperature. The results from the single-crystal X-ray diffraction study can be correlated with Si-29 MAS NMR chemical shifts for the low-temperature phase. At low temperatures the results show that the positive thermal expansivity is driven by an overall increase in Si-Si distances related to an increase in Si-O-Si bond angles. However, in the high-temperature phase the Si-O-Si angles are approximately invariant with temperature, and the negative thermal expansion in this case is caused by transverse vibrations of the Si-O-Si units