An investigation of the radiation polymerization of methyl methacrylate-kaolin clay composites

A kinetic and characterization study has been made on the effects of gamma-rays (Co⁶⁰) on the polymerization of a 50-50 weight mixture methyl methacrylate (MMA) kaolin clay system. The effect of dose rate (7.35 - 24.9 rads per second), temperature (25 to 75ºC) and total dose on the percentage conversion of monomer to polymer was studied. The rate of formation of polymer at 25ºC in the composite system was found to be faster when compared to a bulk MMA system at the same experimental conditions. This acceleration showed that the clay had a catalytic effect on the formation of polymer. The effect decreased as temperature increased. Rate data and apparent activation energies are reported. Two types of polymethylmethacrylate (PMMA) were formed in the composite. One type was called homopolymer and could be removed from the composite by extraction with organic solvents. The other type was called inserted polymer and could only be removed by dissolving the clay matrix with hydrofluoric acid. Characterization studies showed that the homo and inserted polymer exhibited the following characteristics: 1. NMR spectra showed that both polymers had increased isotacticity as compared to bulk polymer 2. the viscosity average molecular weights of the homopolymer ranged from (0 .4 x 10⁶ to 5 x 10⁶) depending upon the dose rate, temperature and total dose received. 3. gel permeation chromatography studies confirmed the increase of molecular weight for the homopolymer and showed the same peak molecular weights and distribution for the inserted polymer. 4. infrared spectroscopy showed no differences in the structure of either type of polymer. X-ray, particle size gravimetric thermal analysis (DTA-TGA) and surface area measurements were used to characterize the clay. Mechanical tests, DTA-TGA and scanning electron microscopy were used to characterize the entire composite. A discussion on the potential uses of PMMA-kaolin clay composites is presented along with suggested future work in this area of research --Abstract, pages ii-iii

Towards a Vaccine against Plasmodium vivax Malaria

The authors discuss a new study that suggests thatPlasmodium vivax Duffy-binding protein could be a candidate antigen for developing aP. vivax vaccine

Evaluating the Impact of a Quiz Question within an Educational Video

Educational videos are becoming more prevalent within a higher education context and the use of videos is now taken for granted. However, the full impact videos have on learning is under researched and not fully known. This study was conducted to investigate the effectiveness of quiz questions embedded throughout a video. Students from different modules (n1 = 102, n2 = 23) watched three different formats of videos and subsequent results of a multiple choice test were recorded and compared. In addition, viewing behaviour was recorded and explored to evaluate if this also impacted upon results. Results highlighted, that the performance on tests significantly improved after watching the video with embedded quiz questions throughout. Contrary to the test scores, students’ perceptions did not identify any differences, however students’ qualitative comments showed overwhelming support for quizzes embedded throughout a video. Implications on professional practice and further research to build upon this study are discussed

Development of fluorescent Plasmodium falciparum for in vitro growth inhibition assays

<p>Abstract</p> <p>Background</p> <p><it>Plasmodium falciparum </it><it>in vitro </it>growth inhibition assays are widely used to evaluate and quantify the functional activity of acquired and vaccine-induced antibodies and the anti-malarial activity of known drugs and novel compounds. However, several constraints have limited the use of these assays in large-scale population studies, vaccine trials and compound screening for drug discovery and development.</p> <p>Methods</p> <p>The D10 <it>P. falciparum </it>line was transfected to express green fluorescent protein (GFP). <it>In vitro </it>growth inhibition assays were performed over one or two cycles of <it>P. falciparum </it>asexual replication using inhibitory polyclonal antibodies raised in rabbits, an inhibitory monoclonal antibody, human serum samples, and anti-malarials. Parasitaemia was evaluated by microscopy and flow cytometry.</p> <p>Results</p> <p>Transfected parasites expressed GFP throughout all asexual stages and were clearly detectable by flow cytometry and fluorescence microscopy. Measurement of parasite growth inhibition was the same when determined by detection of GFP fluorescence or staining with ethidium bromide. There was no difference in the inhibitory activity of samples when tested against the transfected parasites compared to the parental line. The level of fluorescence of GFP-expressing parasites increased throughout the course of asexual development. Among ring-stages, GFP-fluorescent parasites were readily separated from uninfected erythrocytes by flow cytometry, whereas this was less clear using ethidium bromide staining. Inhibition by serum and antibody samples was consistently higher when tested over two cycles of growth compared to one, and when using a 1 in 10 sample dilution compared to 1 in 20, but there was no difference detected when using a different starting parasitaemia to set-up growth assays. Flow cytometry based measurements of parasitaemia proved more reproducible than microscopy counts.</p> <p>Conclusions</p> <p>Flow cytometry based assays using GFP-fluorescent parasites proved sensitive and highly reproducible for quantifying the growth-inhibitory activity of antibodies and anti-malarials, with superior reproducibility to light microscopy, and are suitable for high-throughput applications.</p

Abstract for IDCC 2013 Poster Sessions

Open Exeter is a JISC-funded project investigating how best to embed good practice in research data management and Open Access in the research lifecycle. This is essential to ensure compliance with funder policies and that the maximum possible benefits of exposing data accrue at an individual and institutional level. So that we can help researchers and postgraduate students to comply with funder and institutional policy, we are developing a range of integrated training courses and resources, using different formats, styles and content tailored for differing audiences.JIS

Application of the Malaria Management Model to the Analysis of Costs and Benefits of DDT versus Non-DDT Malaria Control

Introduction: DDT is considered to be the most cost-effective insecticide for combating malaria. However, it is also the mostenvironmentally persistent and can pose risks to human health when sprayed indoors. Therefore, the use of DDT for vectorcontrol remains controversial.Methods: In this paper we develop a computer-based simulation model to assess some of the costs and benefits of thecontinued use of DDT for Indoor Residual Spraying (IRS) versus its rapid phase out. We apply the prototype model to theaggregated sub Saharan African region. For putting the question about the continued use of DDT for IRS versus its rapidphase out into perspective we calculate the same costs and benefits for alternative combinations of integrated vectormanagement interventions.Results: Our simulation results confirm that the current mix of integrated vector management interventions with DDT as themain insecticide is cheaper than the same mix with alternative insecticides when only direct costs are considered. However,combinations with a stronger focus on insecticide-treated bed nets and environmental management show higher levels ofcost-effectiveness than interventions with a focus on IRS. Thus, this focus would also allow phasing out DDT in a costeffectivemanner. Although a rapid phase out of DDT for IRS is the most expensive of the tested intervention combinationsit can have important economic benefits in addition to health and environmental impacts that are difficult to assess inmonetary terms. Those economic benefits captured by the model include the avoided risk of losses in agricultural exports.Conclusions: The prototype simulation model illustrates how a computer-based scenario analysis tool can inform debateson malaria control policies in general and on the continued use of DDT for IRS versus its rapid phase out in specific.Simulation models create systematic mechanisms for analyzing alternative interventions and making informed trade offs

Different Life Cycle Stages of Plasmodium falciparum Induce Contrasting Responses in Dendritic Cells

Dendritic cells are key linkers of innate and adaptive immunity. Efficient dendritic cell activation is central to the acquisition of immunity and the efficacy of vaccines. Understanding how dendritic cells are affected by Plasmodium falciparum blood-stage parasites will help to understand how immunity is acquired and maintained, and how vaccine responses may be impacted by malaria infection or exposure. This study investigates the response of dendritic cells to two different life stages of the malaria parasite, parasitized red blood cells and merozoites, using a murine model. We demonstrate that the dendritic cell responses to merozoites are robust whereas dendritic cell activation, particularly CD40 and pro-inflammatory cytokine expression, is compromised in the presence of freshly isolated parasitized red blood cells. The mechanism of dendritic cell suppression by parasitized red blood cells is host red cell membrane-independent. Furthermore, we show that cryopreserved parasitized red blood cells have a substantially reduced capacity for dendritic cell activation

Multiple morbidities in pregnancy: Time for research, innovation, and action

Progress indicators in maternal health in many low- and middle-income countries (LMICs) continue to fall below international standards despite Millennium Development Goal commitments and Sustainable Development Goal (SDG) aspirations [1]. While maternal mortality has fallen by 44% globally since 1990, many countries will struggle to meet the SDG target of fewer than 70 maternal deaths per 100,000 live births by 2030 [2]. Despite substantial efforts, globally over 300,000 women still die each year during pregnancy, childbirth, or the postpartum period, mostly from preventable causes. The burden of morbidity and mortality is inequitable, with vulnerable and marginalized populations at greatest risk. Although this burden disproportionately occurs in LMICs, it also affects increasing numbers of women in some high-income countries [3]. Improved counts of so-called indirect causes highlight the importance of nonobstetric morbidity during pregnancy, contributing around one-third of maternal deaths in LMICs [4]. Indirect causes include the effects of infections, noncommunicable diseases (NCDs), and mental health disorders. These highly prevalent conditions overlap and co-occur such that many women experience multimorbidity during and around pregnancy

Dendritic Cell Responses and Function in Malaria

Malaria remains a serious threat to global health. Sustained malaria control and, eventually, eradication will only be achieved with a broadly effective malaria vaccine. Yet a fundamental lack of knowledge about how antimalarial immunity is acquired has hindered vaccine development efforts to date. Understanding how malaria-causing parasites modulate the host immune system, specifically dendritic cells (DCs), key initiators of adaptive and vaccine antigen-based immune responses, is vital for effective vaccine design. This review comprehensively summarizes how exposure to Plasmodium spp. impacts human DC function in vivo and in vitro. We have highlighted the heterogeneity of the data observed in these studies, compared and critiqued the models used to generate our current understanding of DC function in malaria, and examined the mechanisms by which Plasmodium spp. mediate these effects. This review highlights potential research directions which could lead to improved efficacy of existing vaccines, and outlines novel targets for next-generation vaccine strategies to target malaria