Recent progress in the synthesis of nanostructured magnesium hydroxide

This review highlights synthetic routes for producing nanostructured magnesium hydroxide and focuses on how these various preparative approaches can produce Mg(OH)2 nanoparticles with controlled size and morphology. Mg(OH)2 nanocrystals with rod-, needle-, hollow tube- or platelet-like morphology can be synthesised by the modification of chemical and physical experimental parameters such as the selection of magnesium precursor, solvent and temperature or by employing surface modifiers and templates. Techniques based on hydrothermal/solvothermal treatments, microwave heating and (co-)precipitation are dominant in the production of Mg(OH)2 at the nanoscale, but other materials design approaches are now emerging. Bulk Mg(OH)2 has been extensively studied over decades and finds use in a wide range of applications. Moreover, the hydroxide can also serve as a precursor for other commercially important materials such as MgO. Nanostructuring the material has proven extremely useful in modifying some of its most important properties – not least enhancing the performance of Mg(OH)2 as a non-toxic flame retardant – but equally it is creating new avenues of applied research. We evaluate herein the latest efforts to design novel synthesis routes to nano-Mg(OH)2, to understand the mechanisms of crystallite growth and to tailor microstructure towards specific properties and applications

Believe in these things : magical realism\u27s postmodern use of religious language

Magical realism has expanded from a genre squarely located within postcolonialism to one that includes many non-colonial, Western writers such as Karen Russell and Helen Oyeyemi. Using Russell’s Swamplandia!, Salman Rushdie’s Midnight’s Children, and Oyeyemi’s The Icarus Girl as representative texts, this thesis extends Frederic Jameson’s theory of “effacement” and Jean-François Lyotard’s “postmodern condition” to investigate the spread of the magical realist genre and techniques beyond its postcolonial beginnings and into a postmodern means to insert an element of the unknown back into a scientifically bound, prosaic reality. These magical Realist authors create their effects largely by using the trappings of religions, specifically its language, symbols, and mindsets. Jameson and Lyotard, along with Brian McHale, and critics Lois Parkinson Zamora, Wendy B. Faris, and Amaryll Chanady, provide insightful ideas, theories, and platforms with which to critically study the origin and implications of this shift in the genre

Effect of block face shell geometry and grouting on the compressive strength of concrete block masonry

Canadian and American standards provide the compressive strength of concrete masonry assemblage as dependent on compressive strength of blocks, mortar type, and percentage of grout. It is common in construction to sporadically place non-standard units in masonry walls. Moreover, grout can have many different mix proportions causing a difference in compressive strength, stiffness, and grout-unit bond strength. This research studied the effect of block geometry and the combination of two different block geometries on ungrouted prism strength. As well, this study focused on the effects of grout strength, grout stiffness, and grout-block bond strength on the compressive strength of grouted masonry prisms. This study showed that block geometry affected prism compressive strength when the prism was comprised of one type of block. This was untrue for prisms with two different geometries. Grout strength and stiffness were found to affect prism strength. Bond strength was found to only affect the stiffness and not the strength of the grouted masonry prisms

Turning up the lights - fabrication of brighter SERRS nanotags

Brighter SERRS nanotags ideal for improved SERRS imaging were prepared by the controlled addition of electrolyte producing a dimer enriched solution, which was incubated with a Raman reporter before being stabilised by a polyethylene glycol (PEG) shell

Ammonia borane-based nanocomposites as solid state hydrogen stores for portable power applications

Ammonia borane (AB) based nanocomposites have been investigated with the aim of developing a promising solid-state hydrogen store that complies with the requirements of a modular polymer electrolyte membrane fuel cell (PEM FC) in a portable power pack system. AB-carbon nanocomposites (prepared via ball milling or solution-impregnation) demonstrate improved hydrogen release performance compared to AB itself in terms of onset temperature and hydrogen purity, while maintaining a gravimetric density of more than 5 wt. % H2. The most promising of these materials is an AB-AC (activated carbon) composite, synthesised via solution-impregnation with an optimal dehydrogenation temperature of 96 °C. When combined with an external nickel chloride filter downstream, no evolved gaseous by-products can be detected above 100 ppb. The feasibility of an AB-AC storage tank has been further endorsed by simulations in which the reaction rate and the hydrogen flux was found to be almost constant as the temperature front propagated from the bottom to the top of the tank after initiation

Generating and Comparing Aggregate Variables for Use Across Datasets in Multilevel Analysis

This article examines the creation of contextual aggregate variables from one dataset for use with another dataset in multilevel analysis. The process of generating aggregate variables and methods of assessing the validity of the constructed aggregates are presented, together with the difficulties that this approach presents

Implementing the water framework directive and tackling diffuse pollution from agriculture: Lessons from England and Scotland

Tackling diffuse pollution from agriculture is a key challenge for governments seeking to implement the European Union's Water Framework Directive (WFD). In the research literature, how best to integrate and align effective measures for tackling diffuse pollution, within the context of the EU's multilevel governance structure, remains an open question. This paper focuses on the first and second implementation cycles of the WFD to explore how national governance arrangements either facilitated or hindered the adoption of effective policies, especially with regards to the delivery of agricultural and water policies on the ground. It draws on data collected through systematic document analysis and interviews with key experts, policymakers and interest groups, and presents a comparative analysis of two case studies: England and Scotland. The case studies show that Scotland's joined-up governance structure, which enabled policymakers and interest groups to work together and to build trust and cooperation, facilitated the adoption of stricter measures for tackling diffuse pollution. In contrast, in England institutional fragmentation prevented a meaningful engagement of all parties and acted as a barrier. The analysis unpacks the design of policy mixes and the conditions that allow national governments to pursue more holistic and integrated governance approaches to overcome opposition from interest groups and gain their support

Pan-Domain Analysis of ZIP Zinc Transporters

The ZIP (Zrt/Irt-like protein) family of zinc transporters is found in all three domains of life. However, little is known about the phylogenetic relationship amongst ZIP transporters, their distribution, or their origin. Here we employed phylogenetic analysis to explore the evolution of ZIP transporters, with a focus on the major human fungal pathogen, Candida albicans. Pan-domain analysis of bacterial, archaeal, fungal, and human proteins revealed a complex relationship amongst the ZIP family members. Here we report (i) a eukaryote-wide group of cellular zinc importers, (ii) a fungal-specific group of zinc importers having genetic association with the fungal zincophore, and, (iii) a pan-kingdom supercluster made up of two distinct subgroups with orthologues in bacterial, archaeal, and eukaryotic phyla

Determinants of obesity and perception of weight in hypertensive patients in rural South Africa

Objective: The objective of the study was to identify factors associated with being overweight or obese, and perceptions of weight by hypertensive patients living in rural South Africa.Design: This was a nested cross-sectional study.Setting: The setting was primary healthcare clinics close to Manguzi Hospital, KwaZulu-Natal.Subjects: Subjects were 109 males and 391 females, prescribed at least one antihypertensive medication aged ≥ 18 years.Outcome measures: The primary outcome measure was body mass index (BMI) ≥ 25 kg/m2. The secondary outcome measure was recognition of being overweight by those with a BMI ≥ 25 kg/m2.Results: The mean age was 58 years. Three hundred and ninety-one (78%) participants were female, and the majority had never been to school or had attended primary school only. Three hundred and eleven (62%) participants were overweight or obese, with a BMI ≥ 25 kg/m2. Factors associated with being overweight or obese included having high cholesterol [adjusted odds ratio (OR) 10.62, 95% confidence interval (CI): 1.22-92.4, p-value 0.032], and having never smoked (adjusted OR 3.22, 95% CI: 1.38-7.52, p-value 0.007. Human immunodeficiency virus (HIV) was associated with a lower risk of being overweight or obese (adjusted OR 0.52 for BMI ≥ 25, 95% CI: 0.31-0.89, p-value < 0.0001). Only 12% of participants who were overweight or obese perceived that they were overweight. Participants with a BMI ≥ 25 kg/m2 were most likely to recognise they were overweight if they had high cholesterol, diabetes or HIV.Conclusion: Almost two thirds of participants were overweight or obese, and of these, only 12% perceived that they were overweight. Educating patients about obesity, particularly when they have other cardiovascular risk factors such as hypertension, is of public health importance.Keywords: obesity, overweight, weight perception, hypertension, body mass inde

Rapid surfactant-free synthesis of Mg(OH)2 nanoplates and pseudomorphic dehydration to MgO

Magnesium hydroxide nanoplates ca. 50 nm in thickness can be prepared over minute timescales via hydrothermal synthesis in a multimode cavity (MMC) microwave reactor. This approach allows ca. 1 g of single-phase Mg(OH)2 to be synthesised in under 3 minutes without the requirement of surfactants or non-aqueous solvents. The hydroxide nanomaterial dehydrates at temperatures >200 K below that of the equivalent bulk material and can be utilised as a precursor for the pseudomorphic synthesis of nanoplates of MgO as investigated by TG-DTA-MS, XRD and SEM measurements. Equally, the pseudomorphic synthesis can be performed by irradiating the Mg(OH)2 nanomaterial with microwaves for 6 minutes to produce single phase MgO