71 research outputs found
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Control of NOx emissions from diesel engines using exhaust gas re-circulation
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The diesel engine currently accounts for 32 per cent of the new passenger car sales in
Europe. In the US, diesel-power is responsible for 94 per cent of all freight movement. Comparing European Stage III standard petrol and diesel passenger car emissions, diesel NOx emissions are still considered a concern. This thesis investigates the mechanisms by which oxides of nitrogen are formed during diesel combustion. It reviews the current methods of controlling NOx emissions, such as retarding fuel injection timing, exhaust gas re-circulation (EGR), water injection and
exhaust after-treatment. Modelling using a phenomenological model, is used to demonstrate the extended Zeldovich mechanism and formation trends, the effects of EGR and the significance of the Zeldovich mechanism rate constants. Modified Zeldovich rate constants are proposed to improve the correlation to measured data. Clearly, EGR is currently the most effective method of reducing NOx emissions from passenger car diesel engines. The way EGR works in suppressing NOx formation is reviewed in detail. Experimentation on a 1.8 litre inline 4-cylinder 4-valve per cylinder DI diesel with a variable nozzle turbine (VNT) turbocharger was used to demonstrate the concept of "additional" EGR on this small automotive engine. "Additional" EGR is the concept whereby a proportion of the EGR is added to the total charge, so that the volumetric efficiency increases as EGR is introduced. By using "additional" EGR, the benefits of lower NOx emissions combined with reduced particulates emissions and improved fuel consumption were clearly demonstrated at two test conditions. The reasons for achieving lower NOx emissions when using a VNT turbocharger and EGR have been explained. Finally, several methods of calculating EGR proportion were used and compared against true mass flow. The use of a CO2 balance was found to be the most accurate method.This study is funded by the Ford Motor Company
The Transcriptome of the Intraerythrocytic Developmental Cycle of Plasmodium falciparum
Plasmodium falciparum is the causative agent of the most burdensome form of human malaria, affecting 200–300 million individuals per year worldwide. The recently sequenced genome of P. falciparum revealed over 5,400 genes, of which 60% encode proteins of unknown function. Insights into the biochemical function and regulation of these genes will provide the foundation for future drug and vaccine development efforts toward eradication of this disease. By analyzing the complete asexual intraerythrocytic developmental cycle (IDC) transcriptome of the HB3 strain of P. falciparum, we demonstrate that at least 60% of the genome is transcriptionally active during this stage. Our data demonstrate that this parasite has evolved an extremely specialized mode of transcriptional regulation that produces a continuous cascade of gene expression, beginning with genes corresponding to general cellular processes, such as protein synthesis, and ending with Plasmodium-specific functionalities, such as genes involved in erythrocyte invasion. The data reveal that genes contiguous along the chromosomes are rarely coregulated, while transcription from the plastid genome is highly coregulated and likely polycistronic. Comparative genomic hybridization between HB3 and the reference genome strain (3D7) was used to distinguish between genes not expressed during the IDC and genes not detected because of possible sequence variations. Genomic differences between these strains were found almost exclusively in the highly antigenic subtelomeric regions of chromosomes. The simple cascade of gene regulation that directs the asexual development of P. falciparum is unprecedented in eukaryotic biology. The transcriptome of the IDC resembles a “just-in-time” manufacturing process whereby induction of any given gene occurs once per cycle and only at a time when it is required. These data provide to our knowledge the first comprehensive view of the timing of transcription throughout the intraerythrocytic development of P. falciparum and provide a resource for the identification of new chemotherapeutic and vaccine candidates
How adolescents who cut themselves differ from those who take overdoses
The aims of this study were to identify in what ways adolescents who cut themselves differ from those who take overdoses, and to investigate the role of contagion in these behaviours. Data from an anonymous self-report questionnaire survey of 6,020 adolescents in 41 schools were analysed. Comparison of 220 adolescents who reported self-cutting in the previous year with 86 who had taken overdoses in the previous year as the sole method of deliberate self-harm (DSH) showed that far more of those who cut themselves had friends who had also engaged in DSH in the same period (OR 2.84, 95% CI 1.5–5.3, P < 0.001), and fewer had sought help from friends before cutting (OR 0.5, 95% CI 0.3–0.9, P < 0.02). Self-cutting usually involved less premeditation. Analyses at both the individual and school level showed that the association between engaging in DSH and exposure to DSH amongst peers was largely confined to girls who cut themselves. There are important differences between adolescents who cut themselves and those who take overdoses. Contagion may be an important factor in DSH by adolescents, especially in girls who cut themselves. These findings are relevant to the design of prevention and treatment programmes
Graphene-based fabrics and their applications: a review
[EN] Graphene has emerged as a revolutionary material in different fields of science and engineering due to its extraordinary properties such as: high electron mobility, high thermal conductivity, mechanical properties, easy functionalization, etc. The field of textiles is continuously integrating new materials to provide fabrics with new functionalities, hence its incorporation on fabrics was a logical step. Its application to the field of textiles has been recently reported, which has allowed the development of textiles with different functionalities such as: antistatic, UV-protecting, electroconductive, photocatalytic, antibacterial, thermal conductivity, energy storage in flexible supercapacitors, electrodes for batteries, sensors, etc. Up to date no review has been written regarding graphene-based fabrics and their applications. The present review aims to fill the existing gap and provide perspectives into the preparation and applications of graphene-based fabrics and yarns.J. Molina wishes to thank to the Spanish Ministerio de Ciencia e Innovacion (contract CTM2011-23583) for the financial support. J. Molina is grateful to the Conselleria d'Educacio, Formacio i Ocupacio (Generalitat Valenciana) for the Programa VALi + D Postdoctoral Fellowship (APOSTD/2013/056).Molina Puerto, J. (2016). Graphene-based fabrics and their applications: a review. RSC Advances. 6:68261-68291. https://doi.org/10.1039/c6ra12365aS6826168291
Prevention of age-related macular degeneration
Age-related macular degeneration (AMD) is one of the leading causes of blindness in the developed world. Although effective treatment modalities such as anti-VEGF treatment have been developed for neovascular AMD, there is still no effective treatment for geographical atrophy, and therefore the most cost-effective management of AMD is to start with prevention. This review looks at current evidence on preventive measures targeted at AMD. Modalities reviewed include (1) nutritional supplements such as the Age-Related Eye Disease Study (AREDS) formula, lutein and zeaxanthin, omega-3 fatty acid, and berry extracts, (2) lifestyle modifications, including smoking and body-mass-index, and (3) filtering sunlight, i.e. sunglasses and blue-blocking intraocular lenses. In summary, the only proven effective preventive measures are stopping smoking and the AREDS formula
The Dow Jones knowledge graph
Dow Jones is a leading provider of market, industry and portfolio intelligence serving a wide range of financial applications including asset management, trading, analysis and bankruptcy/restructuring. The information needed to provide such intelligence comes from a variety of heterogeneous data sources. Integrating this information and answering complex queries over it presents both conceptual and computational challenges. In order to address these challenges Dow Jones have used the RDFox system to integrate the various sources in a large RDF knowledge graph. The knowledge graph is being used to power an expanding range of internal processes and market intelligence products
Cytokine Array Comparisons of Plasma from Cycling Fertile Women on Cycle Day 5 and Ovulation
PROBLEM: To identify plasma immuno-regulatory molecules up or down regulated between the follicular phase and ovulation of the human menstrual cycle.
METHOD OF STUDY: RayBio cytokine arrays were used to screen 174 immuno-regulatory molecules in plasma collected during the follicular phase at menstrual cycle day 5 and at ovulation from five healthy, non-smoking, fertile women of reproductive age not using hormonal contraception.
RESULTS: A total of 23 differentially expressed molecules were found: 10 molecules were differentially up-regulated and 13 down-regulated at ovulation compared with that at the follicular phase (alpha = 0.05, false discovery rate of 0.45).
CONCLUSION: Circulating immuno-regulatory molecules fluctuate over the menstrual cycle in healthy women. The combination of differentially expressed molecules suggests roles in cyclical regulation of angiogenesis and immune cell trafficking
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