Synthesis and characterization of TiO2 nanoparticles chemically coated with zwitterionic polymer brushes

This study introduces a synthetic method to graft zwitterionic poly (2-methacryroyloxyethyl phosphoryl choline) brushes onto TiO₂ nanoparticles with thickness of a few nanometers. The grafting of zwitterionic polymer brushes was characterized by electron microscope measurements, zeta-potential analysis, and thermo-gravimetric analysis. The technique we employed to synthesize those hybrid nanoparticles was a modified seeded emulsion polymerization in which the polymerization loci were changed in the stage of radical initiation and chain propagation. We have found that the polymerization loci should be on the surface for achieving the effective grafting of polymer brushes. From the suspension rheology studies, we have observed that the suspension of our hybrid nanoparticles was dominated by the attractive force as well as by packing volume effect. This unique rheological behavior is expected to be useful for understanding the inter-particle interactions in complex formulations.     

Aging of HDPE Pipes Exposed to Diesel Lubricant

The effects caused upon the physicochemical behavior of high-density polyethylene pipes by exposure to a diesel lubricant were investigated, as a function of time and temperature, by thermogravimetric and gravimetric analysis and by FT-IR. The gravimetric data were satisfactorily described using Fick's law. The fitting of the experimental points showed that diesel, which can be regarded as a model fluid to analyze the effects caused by aromatic unities present in oil derivatives, has a high diffusion rate into HDPE. The FT-IR results showed that no main structural modifications have occurred after exposure, besides solubilization of low molecular weight units. From the analysis performed, physical aging was identified as the aging process occurring when the HDPE pipes came in contact with diesel lubricant.     

Convergence of real per capita GDP within COMESA countries: A panel unit root evidence

This article examines the absolute and conditional convergence of real GDP per capita in the Common Market for Eastern and Southern Africa (COMESA) during the period 1950?C2003. Income departures across countries were evaluated from several panel data unit root tests. We find no evidence supporting the existence of convergence process for the income in the COMESA. Nevertheless, applying economic development criterion allows to identity two absolute convergence clubs into the COMESA, one for the most four developed countries (Egypt, Libya, Mauritius, Seychelles), and one other for the fourteen less developed ones. Thus, we show that most economies of COMESA are locked into a sustained poverty trap process.     

Development of a questionnaire to assay recalled liking for salt,sweet and fat

Liking for a sweet, salty or fatty diet may induce overconsumption of simple carbohydrates, sodium or lipids. Measuring overall liking of the corresponding sensory sensations contributes to understanding the determinants of dietary behaviours. However, no standardized validated questionnaire assaying these sensations is currently available. In the present study, we developed a web-based questionnaire, “PrefQuest”, which measures recalled liking for the following four sensations: salt, fat and salt, sweet, fat and sweet. PrefQuest included four types of items: (1) liking for sweet, fatty-sweet and fatty-salty foods, (2) preferences in the level of seasoning by adding salt, sweeteners, or fat, (3) preferences for types of dishes in a restaurant menu and (4) overall questions about sweet-, salt- and fat-related behaviours. A development study (n = 198) demonstrated that PrefQuest was feasible, well-perceived, only lasted about 20 min and that items were repeatable (overall mean intra-class correlation coefficient: 0.77, SD 0.08). Construct validity was then evaluated on a larger population sample (n = 47 803). The underlying structure within each of the four sensations was determined by exploratory factor analysis and then internally validated by confirmatory factor analysis. After a selection of the most relevant items, the salt, fat-and-salt, sweet, and fat-and-sweet scales exhibited a theoretically meaningful factor structure, unidimensional for the salt scale and with interrelated sub-dimensions for the sweet, fat-and-salt, and fat-and-sweet scales. Based on the fat-and-sweet and fat-and-salt scales, a fat model was also unveiled. For each factor, internal consistency as well as convergent and divergent validities were demonstrated. Overall, PrefQuest is an internally valid and original tool that can be used to assay recalled liking for sweet, salt, and fat considered altogether or separately as fat and salt or fat and sweet, and can be applied to large population surveys.     

Virtual reality for cultural landscape visualization

Although land managers and policy-makers generally have a good experience of what result can be expected from their decisions, they are often faced with difficulty when trying to communicate the visual impact of a management option to stakeholders, particularly when the landscape exhibits a high cultural value. Three-dimensional visualization of the landscape is often used for communicating with the stakeholders. A challenge in participatory methods for integrated assessment and policy planning is to view future changes in land use, according to scenarios. A 3-D landscape visualization component, SLE (“Seamless Landscape Explorer”), has been developed, which is launched after a scenario simulation to allow for exploration of landscape changes. Pressures causing such changes are translated into changes in the spatial configuration of the landscape. The different types of land-use are visualized thanks to a library of detailed textures, and vegetation can be added. This has been applied to a study of four scenarios in the French Mediterranean region, which were set up as part of a participatory process for discussing the planning of the regional peri-urban and agricultural policy, in an area dominated by the typical culturally sensitive Mediterranean matorral, (“garrigue” shrubland) surrounding the Pic Saint-Loup mountain. Examples of visualization are shown and discussed here.     

In utero exposure to extra vitamin D from food fortification and the risk of subsequent development of gestational diabetes: the D-tect study

Background

The primary aim of this study was to assess whether exposure during fetal life to extra vitamin D from food fortification was associated with a reduction in the risk of subsequently developing gestational diabetes mellitus (GDM). Furthermore, we examined whether the effect of the vitamin D from fortification differed by women’s season of birth.

Methods

This semi-ecological study is based on the cancellation in 1985 of the mandatory policy to fortify margarine with vitamin D in Denmark, with inclusion of entire national adjacent birth cohorts either exposed or unexposed to extra vitamin D in utero. The identification of GDM cases later in life among both exposure groups was based on the Danish national health registers. Logistic regression analyses generating odds ratios (ORs) and 95% confidence intervals (95% CIs) were performed.

Results

Women who were prenatally exposed to the extra vitamin D from fortification tended to have a lower risk of subsequently developing GDM than unexposed women (OR 0.87, 95%CI 0.74,1.02, P?=?0.08). When analyses were stratified by women’s season of birth, exposed women born in spring had a lower risk of developing GDM compared to unexposed subjects (OR 0.68, 95%CI 0.50,0.94, p?=?0.02).

Conclusion

This study suggests that prenatal exposure to extra vitamin D from mandatory fortification may lower the risk of developing gestational diabetes among spring-born women.

Trial registration

This study is part of the D-tect project, which is registered on clinicaltrials.gov: NCT03330301.

     

Distinct and combined effects of disciplinary composition and methodological support on problem solving in groups

Several reasons for the use of multidisciplinary teams composed of individuals with natural science and engineering background in problem‐solving processes exist. The most important are the integration of science‐based technologies into products and processes, and benefits for the problem‐solving process thanks to new knowledge and new perspectives on problems. In this study we analyse the implications of interdisciplinary (science – engineering) group problem solving from a managerial as well as from a cognitive perspective. We then report on an experiment investigating the impact of problem‐relevant disciplinary group composition and methodological support on the problem‐solving process and its outcome. The findings of the experiment have managerial, theoretical, and pedagogical implications related to early phases of New Product/Process Design processes in high‐technology and scientific knowledge‐related domains.     

Unraveling transboundary water security in the arid Americas

ABSTRACT

Transboundary waters are characterized by diverse and complex socio-politico-economic obstacles to effective water management. We examine five distinct cases in the arid Americas – in locations from the US–Mexico border to the Andes mountains – employing water security as a conceptual prism to unravel the multiple and varied attributes of transboundary water challenges. We describe how borders complicate water security in arid regions and explore how institutional arrangements and practices – within and across jurisdictions – respond to these challenges. We find that institutional capacity is needed on multiple levels for effective water management, and institutions must be responsive and flexible to change.