Phase Behavior of DPPC in a DNA-Calcium-Zwitterionic Lipid Complex Studied by Small-Angle X-ray Scattering

In the presence of DNA and calcium, multilamellar liposomes of DPPC when in excess form complexes in which two distinct lamellar lipid phases coexist. The structure and phase behavior of both of these have been investigated using high-resolution small-angle X-ray scattering. The coexisting lipid phases exist within the same precipitated condensate with the phase behavior of the unbound lipid being affected by the complexed lipid phase. While the thermotropic phase transitions of the uncomplexed lipid from Lβ‘-Pβ‘-Lα occur as expected, the transitions of the bound lipid are substantially altered. This is manifested as an increase in the main transition temperature, Tm, of the bound lipid, which has been observed before (Tarahovsky, Y. S.; Khusainova, R. S.; Gorelov, A. V.; Nicolaeva, T. I.; Deev, A. A.; Dawson, K. A.; Ivanitsky, G. R. FEBS Lett. 1996, 390, 133. Kharakoz, D. P.; Khusainova, R. S.; Gorelov, A. V.; Dawson, K. A. FEBS Lett. 1999, 446, 27). However, we also observe an apparent disappearance of the ripple phase (Pβ‘) with increasing calcium concentration in the bound lipid phase. In addition we are in a position to comment on the mechanism of formation for complexes prepared in this way

Environmental auditing of a packaging system for redesign: A case study exploration

Within the United Kingdom a significant portion of the energy consumed each year is done so through industry. It is therefore desirable to take measures that reduce this consumption. A process common to all manufacturing sectors is that of packaging, and this research focused on identifying, quantifying and reducing the environmental impact of one such system. It finally took the form of an abridged life cycle assessment focusing on the manufacturing and assembly stage of a packaging systems life. Two separate studies were conducted to evaluate the performance of specific tools for such environmental studies. Where, the total embodied energy and carbon of each sub-assembly of the systems was calculated and their contribution to the whole machine established. These were further broken down into material production and machine processes in order to establish where the major impacts were and potential areas for redesign. Both approaches were found to be resource hungry in their application, an output that may restrict their application in the type of company that operate in this domain. A surprising finding was that producing a design with lower environmental impact could be less expensive

A hazard model of the probability of medical school dropout in the United Kingdom

From individual level longitudinal data for two entire cohorts of medical students in UK universities, we use multilevel models to analyse the probability that an individual student will drop out of medical school. We find that academic preparedness—both in terms of previous subjects studied and levels of attainment therein—is the major influence on withdrawal by medical students. Additionally, males and more mature students are more likely to withdraw than females or younger students respectively. We find evidence that the factors influencing the decision to transfer course differ from those affecting the decision to drop out for other reasons

An Evaluation of the Student Experience to Inform Strategic Decision Making in Tertiary Education

The need for enhancing the student experience in tertiary education has been widely documented. It is generally agreed that students need to be more engaged with their own learning to achieve this. This paper takes an applied approach and examines some of the ‘academic instruments’ that are used in third level institutions that impact directly on the student experience and consequently their levels of engagement. For the purpose of this study, ‘academic instruments’ are examined under the following headings: Teamwork, Learning Management System, and Self-Directed Study. Adopting a qualitative approach, the research explored these issues with a representative sample of students from one department in a third level college in Ireland. The findings illustrate that student-centred approaches are key to engaging students and enhancing the overall quality of their college experience. Resulting from the empirical research are a number of interventions that when actioned, could result in a more motivated and engaged student population and consequently have the potential to improve student learning and the overall student experience. The changing needs of a diverse student population and their interaction with the learning environment must be understood fully to inform strategic decision making

Developing Communities of Practice in Tertiary Education: Improving Teaching and Learning

There is considerable evidence that the development of Communities of Practice (CoP) in education results in improvements in teaching and learning. The reality far too often, however, is that academics remain isolated in their practice with a culture of individualism rather than collaboration the norm. Adopting a case study approach, this research explores the perspectives of academic staff in one department in Cork Institute of Technology (CIT) on CoP. Specifically, the research explores how communities of practice might develop in a third level teaching environment; the type and nature of communities of practice that might develop and if those communities of practice have a resulting impact on teaching and learning. The findings indicate that not only is there an enthusiasm for collaboration and the development of CoP, but that moreover is something that would be welcomed by staff in the department. The research concludes that a significant opportunity now exists to stimulate and support the development of CoP among educators; a move which would have the twofold benefit of both motivating staff and enhancing the student experience

Preparation of polymeric diacetylene thin films for nonlinear optical applications

A method for producing polymeric diacetylene thin films having desirable nonlinear optical characteristics has been achieved by producing amorphous diacetylene polymeric films by simultaneous polymerization of diacetylene monomers in solution and deposition of polymerized diacetylenes on to the surface of a transparent substrate through which ultraviolet light has been transmitted. These amorphous polydiacetylene films produced by photo-deposition from solution possess very high optical quality and exhibit large third order nonlinear optical susceptibilities, such properties being suitable for nonlinear optical devices such as waveguides and integrated optics

Photodeposition of amorphous polydiacetylene films from monomer solutions onto transparent substrates

Polydiacetylenes are a very promising class of polymers for both photonic and electronic applications because of their highly conjugated structures. For these applications, high-quality thin polydiacetylene films are required. We have discovered a novel technique for obtaining such films of a polydiacetylene derivative of 2-methyl-4-nitroaniline using photodeposition from monomer solutions onto UV transparent substrates. This heretofore unreported process yields amorphous polydiacetylene films with thicknesses on the order of I micron that have optical quality superior to that of films grown by standard crystal growth techniques. Furthermore, these films exhibit good third-order nonlinear optical susceptibilities; degenerate four-wave mixing experiments give x(3) values on the order of 10(exp -8) - 10(exp -7) esu. We have conducted masking experiments which demonstrate that photodeposition occurs only where the substrate is directly irradiated, clearly indicating that the reaction occurs at the surface. Additionally, we have also been able to carry out photodeposition using lasers to form thin polymer circuits. In this work, we discuss the photodeposition of polydiacetylene thin films from solution, perform chemical characterization of these films, investigate the role of the substrate, speculate on the mechanism of the reaction, and make a preliminary determination of the third-order optical nonlinearity of the films. This simple, straightforward technique may ultimately make feasible the production of polydiacetylene thin films for technological applications

Picophytoplankton biomass distribution in the global ocean

The smallest marine phytoplankton, collectively termed picophytoplankton, have been routinely enumerated by flow cytometry since the late 1980s during cruises throughout most of the world ocean. We compiled a database of 40 946 data points, with separate abundance entries for Prochlorococcus, Synechococcus and picoeukaryotes. We use average conversion factors for each of the three groups to convert the abundance data to carbon biomass. After gridding with 1? spacing, the database covers 2.4% of the ocean surface area, with the best data coverage in the North Atlantic, the South Pacific and North Indian basins, and at least some data in all other basins. The average picophytoplankton biomass is 12 ± 22 µg Cl-1 or 1.9 g Cm-2. We estimate a total global picophytoplankton biomass of 0.53–1.32 Pg C (17–39% Prochlorococcus, 12–15% Synechococcus and 49–69% picoeukaryotes), with an intermediate/best estimate of 0.74 Pg C. Future efforts in this area of research should focus on reporting calibrated cell size and collecting data in undersampled regions

Sociodemographic Variation in Consumption Patterns of Sustainable and Nutritious Seafood in Australia

National dietary guidelines (DGs) consistently recommend consuming seafood for health benefits, however, the sustainability of increasing seafood consumption is often challenged. Seafood products vary in environmental performance as well as health benefits, yet there is no information integrating the health and ecological impacts of different seafood choices. The first step in optimising improved health and environmental outcomes is to examine more closely the types of seafood being consumed at population and individual levels, to develop the means to increase the intake of seafood that is optimal for human health and the environment. The purpose of this analysis was to better understand the specific types and amounts of seafood consumed by the Australian population, and by socioeconomic subgroups within the population, to determine the relative nutritional content and sustainability of seafood consumed by these groups. Secondary analysis of the Australian Health Survey (AHS) (2011–2013), which reached 32,000 people (25,000 households) was undertaken. The majority of respondents (83%) did not consume any seafood on the day of the survey. Results indicated the proportion of seafood consumers was lowest among adults who were unemployed, had the least education and were the most socio-economically disadvantaged. Crustaceans and farmed fish with low omega 3-content, such as basa and tilapia, were identified as the least nutritious and least sustainable seafood categories. These two categories constituted a substantial amount of total seafood intake for the lowest socio-economic consumers, and over 50% for unemployed consumers. In contrast, consumers in the highest socio-demographic group consumed mainly high trophic level fish (moderate nutrition and sustainability) and farmed fish with high omega-3 content (high nutrition, moderate sustainability). Fewer than 1% of adults or children reported eating seafood identified as both more nutritious and less resource intensive, such as small pelagics or molluscs. Opportunities exist to increase seafood intakes to improve health outcomes by varying current seafood consumption patterns to maximise nutritional outcomes and minimise environmental impacts. Initiatives to promote the health and environmental benefits of seafood should be promoted at the population level, with targeted interventions for specific groups, and should encourage consumption of highly nutritious low resource intensive types of seafood