35 research outputs found
Optimum global regulatory approaches for in-vitro diagnostic (IVD) instrumentation product development /
No full textAn analysis of performance in mathematics for technology undergraduates and an investigation of teaching interventions for these students
No full textDeclining standards in students’ mathematical competency levels has become a major issue in mathematics education both nationally and internationally (Smith 2004; Kajander and Lovric 2005; Gill et al 2010). This decline in standards, which has commonly become known as the ‘Mathematics Problem’, refers to issues such as poor numeracy skills in beginning undergraduates, difficulties with basic arithmetic and algebraic manipulations and an inability to cope with mathematics which is presented in unfamiliar formats (Hourigan and O’Donoghue 2007). Economists and educationalists agree that competent citizens in the area of mathematics and science are necessary for a successful economy (OECD 2006; Breen et al 2009; IBEC 2010). The need to try and overcome, or at least alleviate somewhat, the ‘Mathematics Problem’ has therefore been a priority of many third level institutions worldwide (Croft 2000; Tonkes et al 2005; Symonds et al 2008). Third level institutions have introduced a variety of different mathematical support structures in an attempt to support their mathematically less prepared students. One popular example of this is the introduction of diagnostic testing which aims to establish where students’ difficulties may lie and to identify the students within a particular cohort who are most ‘at risk’ of failing university mathematics courses. The University of Limerick (UL) introduced diagnostic testing in 1997. The same diagnostic test is still distributed today and so a large dataset has been created which currently consists of data on almost 8,000
students between 1997 and 2010. Diagnostic test data has been found to provide valuable
research opportunities such as the profiling of mathematics students over time (Kannemeyer 2005; Wilson and MacGillivary 2007; Faulkner et al 2010). Another popular use of diagnostic testing, which is prevalent in international education literature, is the prediction of students’ mathematical achievement (Simonite 2004; Barry and Chapman 2007; McDonald 2008). The wealth of data contained in the UL dataset and the examination of literature in the area of the ‘Mathematics Problem’ led the author to investigate the profile of third level mathematics students over time. An investigation into the profile of ‘at risk’ mathematics students over time enabled the author to create a predictive model of performance in mathematics. Finally the author used these research findings to inform a mathematics intervention which was implemented in UL. The intention of these investigations is to further quantify the ‘Mathematics Problem’ so as to inform and improve the teaching and learning of mathematics both nationally and internationally
Controlled release of the histone deacetylase inhibitor sodium butyrate for increasing recombinant protein production /
No full textImproving the yields of biopharmaceutical products from mammalian cell culture is
of paramount importance to manufacturing companies; increasing product yield
includes enhancing recombinant gene expression in mammalian cells. One avenue
for investigation is the use of histone deacetylase inhibitors, such as sodium
butyrate, which function by opening up genomic DNA for transcription. However, a
limitation to the use of sodium butyrate is its toxicity. This research aimed to
examine the controlled release of sodium butyrate onto CHO-K1 cells, to increase
recombinant protein production, while minimizing loss of viability.
Reused lobster exoskeleton was demineralised and deproteinated and was used as
a release vehicle due to its nanoporous biocompatible structure. Biocompatibility of
the shell was confirmed by in vitro toxicity assays. Adsorption and release of
butyrate was measured by GC-MS and the effect of sodium butyrate on
recombinant protein (human insulin-GFP) production in CHO K1-INS/GFP clonal cells
was quantified using fluorescent microscopy. Cell viability was quantified using the
dyes neutral red, propidium iodide and Hoechst staining.
When compared on a per mM basis, controlled release of 100mM sodium butyrate
via the lobster shell (7.69 mM actual release) at 24 hours (p=0.0218) and 48 hours
(7.47 mM actual release) (p=.0454) resulted in statistically significant increases in
protein production compared to 25mM bolus exposure. 250mM controlled release
(21.86 actual release) was higher at 48 hours compared to 25mM bolus exposure
(p=0.0221). Concurrently, cell viability for controlled release at 48hrs was 99.75%
for 100mM and 99.46% for 250mM. For the bolus dose data, the viability at 48hrs
was 99.70% for 5mM, 98.36% for 10mM and 93.20% for 25mM, indicating a
moderating effect of controlled release on butyrate associated toxicity.
xi
A burst release mechanism for the release of sodium butyrate from the shell is
suggested based on release data. Meanwhile, the activation of autophagic
prosurvival and anti-apoptotic pathways; which are likely to be active under the
conditions of increased protein production by controlled butyrate exposure in
comparison to bolus dosing, are proposed as mechanisms for improved cell survival.
The study concludes that controlled release of sodium butyrate could be used to
significantly improve protein yields in biologics manufacturing, and the use of
reused lobster exoskeleton presents a viable vehicle for release
Ternary chalcogenides and their composites with titanium dioxide for photocatalytic applications /
No full textThis thesis addresses the preparation of semiconductor nanomaterials and their
composites with ternary chalcogenides (TC) for photocatalytic applications. Rapid
depletion and ever-increasing demand for fossil fuels have posed some grave
challenges. Rising global temperature and population are the key elements of
concern to the energy shortage and environmental pollution. Heterogeneous
photocatalysis, in the past decade, has deemed to be an effective route for producing
greener energy and environmental remediation. Ternary chalcogenides (TC) with
remarkable visible light absorption, are identified as an ideal candidate to form
heterostructure with classical semiconductors such as TiO2. In the present
investigation, heterostructure nanocomposite of AgBiS2-TiO2, AgInS2-TiO2, AgBiSe2-
TiO2 and AgInSe2-TiO2 composites are synthesised utilising two-step calcination and
solvothermal technique. The study also contributes to the process optimisation of
the TC nanoparticles synthesis.
Computational analysis was utilised to study the structural, electronic and optical
properties of the pristine parent samples. This aided in validating the results
obtained experimentally as well as to understand the charge transfer mechanism
within the heterojunction creation. The XRD results confirm the formation of the
parent TC nanoparticles of different crystal structure and anatase phase of titania.
The minor shift in binding energies in XPS, red shift observed in Raman spectra, and
the TEM results illustrate the successful heterostructure formation. The UV-DRS
pattern for all the composites shows enhanced visible light absorption due to the
coupling of TC. The band gap of the composites decreased with increased doping
levels.
Moreover, these materials were studied for their photocatalytic efficiency, by
photocatalytic degradation of Doxycycline, photocatalytic hydrogen generation and
photocatalytic antimicrobial disinfection. The composite samples illustrated more
than 95% degradation results within 180 minutes and showed about 5 log
reductions of bacterial strains (E. coli and S. aureus) within 30 minutes of irradiation.
10
The hydrogen production results were promising as all the composites samples
displayed higher efficiencies compared to their parent samples. The PL
measurement also validated the enhanced activity exhibited by the composite
structures, as the intensity of the composite samples gets dampened compared to
pristine TiO2, which suggests the decreased rate of recombination. A mechanism for
the enhanced photocatalytic activity is proposed based on scavenging experiments
and theoretical analysisn
Ternary Metal Chalcogenide Heterostructure (AgInS2–TiO2) Nanocomposites for Visible Light Photocatalytic Applications
No full textHybrid nanoarchitectures of AgInS2 and TiO2 photocatalysts were prepared by using a modified sol–gel method. The experimental results reveal that these nanocomposites display enhanced visible light absorption and effective charge carrier separation compared to their pristine parent samples (AgInS2 or TiO2). 0.5 wt % AgInS2 loading was found to be the optimum concentration for photocatalytic applications. More than 95% of doxycycline degradation was achieved within 180 min of solar light illumination. Similarly, the dopant concentrations at lower values (<2 wt %) exhibited 300 times higher H2 generation rate under visible light irradiation compared to AgInS2 and TiO2. The microbial strains (Escherichia coli and Staphylococcus aureus) exhibited a 99.999% reduction within half an hour of simulated solar light illumination. The computational investigation was employed to understand the structural, electronic, and the dielectric properties of AgInS2 and TiO2 composites. The improved photocatalytic results are explained as a result of the decreased rate of exciton recombination. The current investigation opens up new insights into the use of novel ternary heterostructure nanocomposites for improved visible light activity
From the 'Rescue of the Nation State' to the Emergence of European Spaces. EUIJ-Kansai Workshop on "New Research Horizons of the History of European Integration", May 10, 2008, Toyonaka (Osaka)
No full textThe aim of this paper is to make some contribution to the discussion on the future direction of the historical research on the European integration processes. What I intend to do here is, broadly, to link the contemporary European studies to the Historical studies, and concretely, to emphasise the transnational dimension of European integration. This exercise should be read as presenting my "wish list" to the Integration Historians
Toxicity of Nanomaterials: Exposure, Pathways, Assessment, and Recent Advances /
No full textGrowth in production of manufactured goods and the use of nanomaterials in consumer products has mounted in the past few decades. Nanotoxicology or toxicity assessment of these engineered products is required to understand possible adverse effects and their fate inside the human body. The present review is a one stop assessment intended to be a state of the art understanding on nanotoxicity. It provides a summation of the various kinds of cell death and also discusses the different types of toxicities along with their studies. The review discusses the physiological impact imparted on cells (reactive oxygen species generation and the resultant oxidative stress, inflammation, and other nonoxidant pathways). Moreover, it discusses the different physicochemical properties of nanomaterials (size, morphology, surface charge, and coating) governing the cytotoxicity properties. It also details the major pathways of nanomaterial uptake in cells and their outcome. Additionally, it also discusses the possible methods for human exposure to nanomaterials (skin, respiratory tract, gastrointestinal tract, blood brain barrier, liver, and spleen). Furthermore, an entire new section is contributed in discussion of all possible types of assays (cytotoxicity, cell proliferation, and genotoxicity assays). A summarized discussion of the recent advances on in vitro, in silico, and in vivo studies of nanomaterials (metal, metal oxides, carbon nanotubes, graphene, and other novel materials) is made. The review also provides a brief account of the safety guidelines for handling nanomaterials. Finally, the uses of engineered nanomaterials in commercial products are discussed in detail.ye
