PhD, EngD and MSc by research theses (Cranfield Health)

Permanent URI for this collection

https://dspace.lib.cranfield.ac.uk/handle/1826/2004

Browse

Now showing 1 - 20 of 175

Open Access
Advanced manufacturing processes for the production of biosensors
(Cranfield University, 1998-08) Newman, Jeff D.; Turner, Anthony P.F.
Biosensors were first described over thirty five years ago, but commercialisation did not occur until the early 1970s. Interest was subsequently sparked by the market for large numbers of disposable devices required for self-testing of blood glucose levels by diabetic patients. The introduction of automated production technology, for the manufacture of the millions of devices required, became a necessity. Screen printing has been the most successful of these technologies to date, but there are many other techniques which could be applicable to biosensor production. This thesis reviews the main technologies used in sensor construction and describes the manufacture of some devices using a range of these processes. The construction of transducers and subsequent chemically- and biologically-sensitive layers, as well as membrane structures are considered. Most of the work presented here concerns the manufacture of electrochemical devices, but many of the techniques described would be equally applicable to certain aspects of the production of other classes of biosensors.
Open Access
Advancing the clinical application of Raman spectroscopic diagnosis of oesophageal pre-malignancies
(Cranfield University, 2009-01) Hutchings, J.; Stone, Nicholas; Kendall, Catherine; Barr, H.
Raman spectroscopy is a technique that utilises inelastic scattering processes to provide a biochemical fingerprint that has been shown to successfully discriminate oesophageal pathologies. The aim of this study was to develop Raman spectroscopy as a clinical tool; both in vivo for ‘targeted biopsy’, and in ex vivo for ‘automated histopathology’. Two different Raman probes were evaluated and compared and tissue classification models generated ex vivo. A preliminary classification model of a novel single collection fibre probe demonstrated potential for the probe design. Both probes were shown to discriminate three different oesophageal pathology groups. A cross-validated tissue classification model (88 samples) discriminated normal, Barrett’s and neoplasia with an overall accuracy of 86.5% with a sensitivity of 83.3-89.5% and specificity of 89.2-97.1%. A novel rapid Raman mapping technique was evaluated. It was shown that sufficient biochemical information for pathology diagnosis could be extracted from low signal to noise ratio data using multivariate analysis providing the dataset was sufficiently large, thus demonstrating the feasibility of automated histopathology in a clinically realistic time frame. Furthermore, it was demonstrated that high spatial resolution imaging was not necessarily required for automated histopathology using novel interpretation of multivariate techniques. A tissue classification model generated from two rapid Raman maps containing separated substrate, normal, HGD, luminescence and fibrous connective tissue with an overall training performance of 97.5% Problems limiting clinical implementation of Raman techniques were investigated and methods of overcoming devised.
Open Access
Analysis of volatile marker compounds in body fluid samples from patients with gastrointestinal disease
(Cranfield University, 2010-09) Fowler, Dawn P.; Turner, Claire; Walker, Christopher
Causes of gastrointestinal diseases such as ulcerative colitis (UC) Crohn’s disease (CD) and irritable bowel syndrome (IBS) are not yet completely understood and clinical investigation for diagnosis is invasive, costly and time consuming. Disease may originate from the host or in combination with commensal enteric bacteria, notably sulphate reducing bacteria. Examination of volatile compounds from clinical samples may provide indicators and better understanding into aetiology of these conditions and provide biomarkers for individual disease.Cont/d.
Open Access
Analysis of volatile organic compounds in breath as a potential diagnostic modality in disease monitoring
(Cranfield University, 2011-12) Patel, Mitesh Kantilal; Walton, Christopher
The use of breath odours in medical diagnosis dates back to classical times, though in its modern form the technique is only a few decades old. There are several breath tests in common clinical use, though all of them involve administration of a known or labelled exogenous compound. More recently, over the last twenty years, interest has focussed on analysis of endogenous metabolites in breath, but despite a large number of published studies reporting a number of disease markers, there has been little or no impact on clinical practice. Nonetheless, breath analysis offers a number of potential advantages over current biochemical methods. One major advantage of breath analysis is its non-invasive nature, which has led to significant interest in its use at point-of care for monitoring chronic diseases such as diabetes and the chronic infections ubiquitous in cystic fibrosis. However, breath analysis classically involves the use of expensive laboratory based analytical equipment which requires extensively-trained personnel and which cannot readily be miniaturised. Systems based on simple gas sensors might offer a way of overcoming these limitations. In recent years, Cranfield University has developed an instrument called the single metal oxide sensor gas analyser (SMOS-GA, more commonly referred to as the “Breathotron”) as a proof of concept for sensor-based breath analysis. In this project the Breathotron has been used in conjunction with selected ion flow tube mass spectrometry (SIFT-MS) and thermal desorption gas chromatography mass spectrometry (TD-GC-MS) to determine the changes in the concentrations of volatile organic compounds (VOCs) in breath in a number of experimental situations which a relevant to the diagnostic monitoring of diabetes mellitus. Studies conducted on clinically healthy volunteers were: an oral glucose tolerance test (OGTT); a six minute treadmill walking test; and a bicycle ergometer test. Additionally Breathotron and analytical data were also obtained during a hypoglycaemic clamp study carried out on hypoglycaemia-unaware Type I diabetics. The principle breath volatiles determined analytically were: acetone, acetaldehyde, ammonia isoprene though data on a number of others was also available. In general, it proved difficult to establish any reproducible relationship between the concentration of any compound measured and blood glucose concentration any of the experimental interventions. It was notable, though, that statistically significant associations were observed occasionally in data from individual volunteers, but even these were not reproduced in those trials which involved repeated measurements. This remained true even where spirometry data were used to derive VOC clearance rates. This may explain previous reports from smaller studies of an association between glucose and breath acetone concentration. It seems probable that any experimentally-induced changes in breath VOC concentration or clearance were of much smaller magnitude than background variability and was consequently not detectable. These observations were mirrored in the sensor-derived results. Multivariate analysis across all trials where Breathotron data were obtained suggested clustering by individual volunteer rather than glycaemic status. This suggests that that there exists a “background” breath volatile composition, dependent perhaps on such factors as long-term diet, which is independent of our experimental intervention. The Breathotron was also used as a platform to assess the performance of three different types of mixed metal oxide sensor in vitro. Calibration curves were generated for acetone, ammonia and propanol covering the physiological range of concentrations and with a similar water content to breath. Close correlations were obtained between concentration and the amplitude of the sensor response. Sensor response reproducibility was also determined using acetone at a concentration of 10ppm with dry and humidified test gas. There were significant differences between sensor types in overall reproducibility and in response to humidity. These results suggest that had there been substantial changes in breath VOC composition as a result of our experimental interventions, any of the types of sensor used would have been capable of responding to them. In summary, these results do not support the efficacy of breath VOC analysis as a means of non-invasive diagnostic monitoring.
Open Access
Analytical methods for assessing paper degradation In transformers
(Cranfield University, 2006-05) Christofidis, Stavros; Setford, S.; Ritchie, Laurie; Aldred, David
Power transformers are essential equipments for distributing electricity. However, maintenance of these equipments is necessary to ensure long working life and to avoid catastrophic incidents. Insulation of the instrument is essential, and mainly consists of mineral oil and cellulosic paper. This research work investigates and examines in a series of different experiments the compounds produced from the degradation of the cellulosic paper, known as furanic compounds. Five furanic derivatives (5-HMF, 2-FAL, 2-ACF, 5-MEF and FOL) were examined, and it was established throughout this work that these furanic compounds degradate faster in aqueous solution, under a controlled environment, than in an organic, it is possible to produce from one furanic compound other derivatives, and finally each furanic compound distributes differently in an oil water environment, affecting the recovery of each individual. The knowledge obtained from this research work can be used for the development of the existing method of analysis of furanic compounds, and help to provide a better diagnosis of the insulation state of the transformer.
Open Access
Analytical technology for cleaning verification and analysis of drug purity in pharmaceutical production.
(Cranfield University, 2008-02) Corrigan, Damion K.; Piletsky, Sergey A.; McCrossen, Sean
Production of pharmaceuticals is a complex process which goes beyond the synthetic reactions undertaken to produce the final drug product. In multi purpose manufacturing facilities the equipment used in the processes must be proven to be sufficiently free of residue from the previous compound so that safe manufacture of the next compound can commence. Cross contamination can pose serious health risks so cleaning verification is a process of extreme importance. Pharmaceutical products may contain impurities that originate from the synthetic stages of production, the starting materials or from in situ reactions taking place in the final drug. Some of these impurities may be genotoxic. Genotoxic impurities are a class of impurities for which awareness is currently growing in the pharmaceutical industry. Traditional analytical chemistry methods such as HPLC are currently employed for the detection and quantification of cleaning residues and genotoxic impurities. These methods can be extremely time consuming. The aims of this project are to investigate swab sampling in cleaning verification, to develop alternative analytical methods which speed up and enhance knowledge of the cleaning verification process and to begin the development of an assay system for commonly occurring genotoxic impurities.
Open Access
Antiviral and quality effects of chemical elictors and Cucumber Mosaic Virus (CMV) infection on tomato plants and fruits
(Cranfield University, 2012-05) Kalogirou, Maria; Terry, Leon A.; Varveri, Christina
Cucumber mosaic virus (CMV) has emerged as one of the most serious threats to tomato cultivation in Greece. In the present study the effects of Benzothiadiazoles (BTH) and pyraclostrobin against mechanically or aphid-transmitted CMV in tomato plants, of hybrid F1 Clodin, were investigated in greenhouse experiments. BTH was confirmed as capable of inducing systemic acquired resistance (SAR) in tomato seedlings against CMV, while pyraclostrobin was not. Responses to BTH application and/or CMV inoculation on Spanish tomato hybrid Delos (BTH, BTH+CMV, CMV treatments) were monitored during winter and spring season in Greece. In both seasons the SAR derived from BTH application suppressed CMV. BTH treatment presented increased plant growth, fruit size and marketable tomato yield compared to CMV and BTH+CMV treatments, whereas decreased compared to healthy control. CMV treatment caused the most severe stunting of tomato plants among the examined treatments and resulted in yield loss of marketable fruits, although the total fruit number was higher versus to other treatments. Cont/d.
Open Access
Applications of Raman spectroscopy to urology
(Cranfield University, 2006-07) Hart Prieto, Maria Consuelo; Wright, M.; Ritchie, A. W.; Stone, Nicholas
Raman spectroscopy is an optical technique that can interrogate biological tissues. In doing so it gives us an understanding of the changes in the molecular structure that are associated with disease development. The Kerr gating technique uses a picosecond pulsed laser and fast temporal gating of inelastically (Raman) scattered light. The tissue samples used were taken following fully informed consent and ethics approval. Bladder samples were obtained by taking a biopsy during a TURBT or TURP, prostate samples were taken during TURP and the liver and kidney (pigs) were bought at a supermarket. The bladder and prostate samples were snap frozen in liquid nitrogen and stored in an -80°C freezer until required for experimentation. The liver and kidney tissue were used fresh. The constituent samples were bought from Sigma – Aldrich. Multivariate and least squares analysis were used to ascertain the biochemical basis of the differing pathologies within the bladder and the prostate gland, as well as to test diagnostic algorithms produced by a colleague in our group. Depth profiling through the bladder and prostate gland was shown to be feasible by utilizing the Kerr gating technique as was the suppression of fluorescence from dark tissue (liver and kidney). We have shown for the first time, that we can utilise Raman spectroscopy to determine the biochemical basis of pathologies of the bladder and the prostate gland. With the help of the Kerr gating technique we also obtained spectra from different depths through them. We also suppressed fluorescence and resonantly enhanced Raman spectra from dark tissue. These have major implications in terms of understanding pathogenesis and disease progression and also the potential to accurately assess depth of tumour invasion.
Open Access
Attenuation of quorum sensing using computationally designed polymers
(Cranfield University, 2010-05) Stavroulakis, Georgios; Piletsky, Sergey A.; Tothill, Ibtisam E.; Piletsky, E.; Robinson, G.
It is generally accepted that the majority of Gram-negative and Gram-positive bacteria communicate via production and sensing of small signal molecules, autoinducers. The ability of bacteria to sense their population density is termed quorum sensing (QS). Quorum sensing controls certain phenotypic traits, particularly virulence factors and biofilm formation. In this project a new solution for the attenuation of quorum sensing which involves selective sequestering of the signal molecules using rationally designed synthetic polymers was explored. Cont/d.
Open Access
Attribute analysis and quality assessment of extra virgin olive oil produced in Sitia, Crete, Greece
(Cranfield University, 2011) Kalarchakis, Ioannis; Zafiropulos, Vassilis; Fragkiadakis, Georgios A.; Lydakis, Dimitrios
In this study, extra virgin olive oil produced in the mountainous organic semi- intensive production systems of Krya (Sitia, Crete, Greece) was under investigation in different stages of production. The region is characterized by high altitude, sloping and difficulty to access systems that are considered as high risk of abandonment but its sustainability has extreme survival importance for the local population that consists of producers and suppliers that strive daily to improve this product. The study focuses in principles of cultivation, quality control and marketing in order to assess the production systems of Krya in comparison with other regions. Data suggest that dominant crop practices in the area is harvesting with hand–held mechanical harvesters (100%) and soil cultivation with ploughshares attached to different sizes of tractors, irrigation is applied in most systems in Krya, Pruning and fertilization is also practiced in variable degrees. Temperature measured during different stages of processing seems to have reached 27°C to 35°C suggesting a drop in quality because of high temperature effect to phenolic content. Samples obtained from Krya groves have produced olive oil that was classified as Extra virgin olive oil based in sensory and chemical tests, with average free acidity scores lower than 0.4 %, with average peroxide scores lower than 12 meq/L and K270 index scores lower than 0,15. Sensory results suggest olive oils with high medium fruitiness (< 6) and light sense of bitterness and pungency (< 3) with no defects (0). Several tools are proposed for better evaluation of the standard cultivation practices, sensory characteristics are displayed in specific graph models and the total quality of olive oil is calculated based in specified formula that combined both chemical and sensory results. Based in the Total quality index score formula twenty-four samples obtained from Krya and comparative organic systems are compared with popular olive oils currently dominating the Greek and Cretan market. Finally this study suggests options for improvement of the production stages of cultivation, process and post harvest management that may increase the success of the product and maintain the productivity in the region aiming to become competitive in the global market.
Open Access
Automatic solid-phase synthesis of molecularly imprinted nanoparticles (MIP NPs)
(Cranfield University, 2012-11) Poma, Alessandro; Piletsky, Sergey A.; Guerreiro, Antonio R.
Molecularly Imprinted Polymers (MIPs) are potential generic alternatives to antibodies in diagnostics and separations. To compete with biomolecules in these technological niches, MIPs need to share the characteristics of antibodies (solubility, size, specificity and affinity) whilst maintaining the advantages of MIPs (low cost, short development time and high stability). For this reason the interest in preparing MIPs as nanoparticles (MIP NPs) has increased exponentially in the last decade. Cont/d.
Open Access
Bacteria in heavy metal contaminated soil: diversity, tolerance and use in remediation
(Cranfield University, 2010) Pires, Carlos; Magan, Naresh; Castro, Paula
The objectives of this project were to determine the bacterial diversity in a heavily contaminated metal region of Portugal. Both traditional and molecular based methods were used to identify tolerant strains and species. The most tolerant species were subsequently identified and utilized for examining the potential for using them to immobilize specific metals from contaminated waste streams by comparing different support materials. Heterotrophic bacterial populations were isolated and characterized from a contaminated industrial area in Northern Portugal. In a first sampling, 278 strains were isolated in different solid media. To assess the diversity of this ecological site and to select representative strains, the isolates were screened by using Random Amplified Polymorphic DNA (RAPD)-PCR profiles. Phenotypic characterization, phylogenetic analysis by sequencing the 16S rRNA genes and metal tolerance tests with zinc (Zn), cadmium (Cd) and arsenic (As) were performed with the selected strains. Recovered gram-positive isolates were related to class Actinobacteria and Bacilli. The majority of the isolates were related to genera Microbacterium and Bacillus. Strains from the genus Arthrobacter were also well represented. 16S rRNA gene sequence similarity of the gram-negative isolates showed that they were related to classes γ-Proteobacteria, ß-Proteobacteria, a-Proteobacteria and Flavobacteria. The most frequently isolated taxa were γ-Proteobacteria, related with the genus Pseudomonas, where a large number of isolates were clustered. These genera are common in metal contaminated environments. Many of the strains (approx. 17) had a high level of tolerance to the heavy metals tested. A total of 13 isolates were not able to grow when metals were present. In a second sampling the soil rhizosphere was screened for bacterial populations, using metal-based selective media for isolation. About 42 strains were recovered when metal supplemented media was used. The gram-positive population were predominantly Bacilli and Actinobacteria members. Bacillus, Microbacterium and Arthrobacter were the most common gram-positive genera. Gram-negative genera were from the same classes as in the first sampling however Sphingobacteria was present. γ-Proteobacteria and ß-Proteobacteria were the most common taxa. The isolates were shown to be very resistant to Zn and As, with about half of the isolates able to grow with Cd present. Interestingly, no strains could grow in the presence of metal mixtures. Despite the number of strains recovered in both samplings the majority of the isolates were clustered within a very small number of genera. During the sampling periods two strains showing low similarity to other bacteria were isolated. These strains were characterized and studied in detail justifying their classification as representing two novel species of the genus Chryseobacterium. The names proposed for these organisms are Chryseobacterium palustre sp. nov. (type strain 3A10[type strain) ) and Chryseobacterium humi sp. nov. (type strain ECP37[type strain] ). Three isolates 1C2, 1ZP4 and EC30 belonging to genera Cupriavidus, Sphingobacterium and Alcaligenes respectively, showing high tolerance to heavy metals, were selected for further study in immobilised systems for Zn and Cd removal. In most cases, matrices (alginate, pectate and a synthetic cross-linked polymer) with immobilised bacteria showed better metal removal. 1C2, a strain belonging to the Cupriavidus genera, was able to increased the removal of Zn; EC30, a bacteria related to Alcaligenes, was the most promising candidate for Cd removal, especially when combined with the synthetic polymer. Removal of metals as single or in binary mixtures was also assessed. Cd removal was most effective when single metal solutions were tested using immobilised bacteria and examining metal matrixes. Based on the strains used and the matrices tested, best results were obtained for removal of Zn from binary mixtures with Cd. Potential exists for further studies to exploit these bacterial strain to develop effective bioremediation approaches for the removal of heavy metals from waste water streams.
Open Access
The biochemistry and physiology of different hybrid and grafted eggplants in response to NaCL salinity in soil and hydroponic systems
(Cranfield University, 2013-12) Panagiotakis, Giorgos D.; Dragassaki, Magdalene; Aldred, David
The major problem of salinity n regions of intensive cultivations such as Ierapetra, has started to affect the crop production. This project was designed to study the effects of salinity on several biochemical and physiological parameters in two hybrids of eggplant as grafted and non-grafted. The two hybrids were the Solanum melongena L hybrid Habana and Solanum melongena L hybrid Vernina. The concentrations that were chosen (12.5 25, 50, 100, 150 and 200mM) represent a scale of salt concentration and were cultivated as self rooted plants in soil, hydroponically and hydroponically as grafted. Grafting also seems to play an important role for salinity tolerance. To corroborate the different parameters were used as indicators of salinity affection and quantified. Plant height and number of leaves were affected in all three experiments and for all plant types whether grafted or not. Similar were the results for the dry and fresh weight of stem leaves and fruits. For the physiological function of the plants factors such as chlorophyll fluorescence and photosynthetic rate were affected especially at higher concentrations of NaCL. The chlorophyll content in the leaves, which was also measured, was negatively affected in all hybrids. Biochemical measurements the K and Na concentrations in dry leaves and the enzyme activity of APX, GPX and SOD were also made. The K and Na ion concentrations were similar with other studies presenting a reduction of K and raise of Na as the concentration of salt was rising. Unfortunately the enzyme activity was not affected at the specific experiment so it was not able to find exactly how the salinity affects this factor. Overall the results of grafted plants were better than as self rooted and the Solano torvum plant used as rootstock is more tolerant than the Tomato Resistar also used as rootstock.
Open Access
The biochemistry and physiology of poly-beta-hydroxybutyrate metabolism in methylosinus trichosporium OB3b
(Cranfield University, 1988-09) Williams, A. M.; Best, D. J.
The obligate methanotroph, Methylosinus trichosporium 0B3b synthesised up to 20 % of its dry weight as poly-beta-hydroxybutyrate when grown in batch culture or nitrogen limited continuous culture on a methanol/ammonium salts medium. Four soluble enzymes associated with polymer metabolism, D(-)-3-hydroxybutyrate dehydrogenase (3-HBD), acetoacetyl-CoA synthetase, beta-ketothiolase and acetoacetyl-CoA reductase have been purified from the crude extract of this organism. Detailed kinetic studies were conducted on each enzyme and their role in the regulation of polymer metabolism was assessed. Cont/d.
Open Access
Biodegradation of mixtures of pesticides by bacteria and white rot fungi
(Cranfield University, 2009-04) Gouma, Sofia; Magan, Naresh; Goumas, D.
The objective of this study was to examine the potential for degradation of mixtures of pesticides (chlorpyrifos, linuron, metribuzin) by a range of bacteria and fungi and to relate this capability to enzyme production and quantify the rates of degradation of the components of the mixture of xenobiotic compounds. Overall, although bacteria (19 Bacillus and 4 Pseudomonas species) exhibited tolerance to the individual and micture of pesticides actual degradation was not evident. Five species of white rot fungi were grown on minimal salts agar plates amended with 0, 10 and 30 mg L-1 of chlorpyrifos, linuron and metribuzin, individually and as a mixture with a total concentration 15 and 30 mg L-1. Four of these, T. versicolor, P. gigatea, P.coccineus and P.ostreatus, exhibited very good tolerance to the pesticides. They were also grown on a nutritionally poor soil extract agar amended with a mixture of the pesticides at different concentrations (0-70 mg L-1). Subsequently, the ability of T. versicolor, P. gigatea, P. coccineus to degrade lignin and production of laccase in the presence of mixture of the pesticides was examined as well as their capacity to degrade the pesticide mixture at different concentrations (0-50 mg L-1) in soil extract broth was quantified using HPLC. This showed that only T.versicolor had the ability to degrade linuron, after three weeks incubation although all tested species produced laccase. Subsequently, the temporal degradation rates of T.versicolor was examined in relation to temporal degradation of a mixture of the pesticides chlorpyrifos, linuron and metribuzin with total concentrations 0-50 mg L-1 and the temporal laccase production was quantified over a six week period in relation to ionic and non-ionic water potential stress (-2.8 MPa). These studies showed that the test isolate had the ability to produce very high levels of laccase at -2.8 MPa water potential adjusted non-ionically by using glycerol and quite lower levels in soil extract broth without stress while T.versicolor did not produce laccase at -2.8 MPa when the medium was modified ionically. Finally, T.versicolor was able to degrade the pesticide linuron in all tested water regimes, after five weeks incubation, regardless of the concentration of the mixture. In contrast, about 50% of the metribuzin was degraded, only at at -2.8 MPa water potential adjusted non-ionically with glycerol. Chlorpyrifos and its main metabolite TCP were not detected, possibly, due to a combination of hydrolysis, photolysis and volatilization degradation. The capacity of T.versicolor to degrade linuron in mixtures of pesticides and the production of high levels of laccase, in a nutritionally poor soil extract broth, even under water stress suggests potential application of this fungus in bioremediation.
Open Access
Biodesulphurisation of coal
(Cranfield University, 2001-07) Prayuenyong, P.; Tothill, Ibtisam E.
The emission of sulphur oxides during the combustion of coal is one of the causes of an environmental problem known as acid rain. Biodesulphurisation technology applied as a method to remove sulphur before coal combustion was investigated in this work. The desulphurisation abilities of three specific bacterial strains including Rhodococcus erythropolis IGTS8, R. erythropolis X309 and Shewanella putrefaciens strain NCIMB 8768 have been evaluated. R. erythropolis IGTS8 and X309 were found to be able to remove both inorganic and organic sulphur from model compounds and coal samples. Their abilities to remove sulphur from benzothiophene were observed for the first time. A novel desulphurising bacterium, S. putrefaciens was also found to be able to remove inorganic and organic sulphur from coal samples. The bacterium, however, lost its ability to remove organic sulphur from model compounds during the investigation. R. erythropolis IGTS8 presented the greatest desulphurisation efficiency among the three bacterial strains. Nevertheless, the desulphurisation activity of R. erythropolis IGTS8 was too low for an economical coal biodesulphurisation process as it removed only 32.0% of total sulphur in bituminous coal, and 21.1% of total sulphur in anthracite coal. Alternatively, coal biodesulphurisation can be carried out in inexpensive conditions by using the bacteria inherent in the coal itself. The type of coal has an important effect on desulphurisation efficiency since the sulphur reduction in bituminous coal, which is in a lower rank than anthracite, was greater than the sulphur reduction in anthracite coal. This work also developed and evaluated the analytical methods used in the field. A HPLC method was developed to detect the desulphurisation metabolites of model compounds. The techniques for measuring sulphur in coal were improved.
Open Access
Biodiversity of mycotoxigenic aspergillus species in Egyptian peanuts and strategies for minimizing aflatoxin contamination
(Cranfield University, 2010-12) Sultan, Yousef Yasseen Abdel-Rahmin; Magan, Naresh
Peanuts are an important crop grown in Egypt for either local consumption or export to European markets. The present study examined the importance of mycotoxigenic Aspergilli in Egyptian peanuts from five different regions (Alexandria, El-Beheira, El- Daqahliya, El-Sharqiya, Asyut) in two seasons (2007, 2008). This led to consideration of different potential strategies to control aflatoxigenic A. flavus strains and associated aflatoxin contamination of peanuts. The most common species in peanuts were from Aspergillus section Flavi, Aspergillus section Nigri and Aspergillus section Circumdati. Both qualitative (coconut cream agar) and quantitative analyses (HPLC) were used to analyse the potential mycotoxin production by strains isolated from peanuts. Of a total of 88 Aspergillus section Flavi strains examined, 90% were aflatoxigenic. Cont/d.
Open Access
Bioinformatics solutions for confident identification and targeted quantification of proteins using tandem mass spectrometry
(Cranfield University, 2009-10) Cham, Jennifer A.; Bessant, Conrad; Regan, Stephen
Proteins are the structural supports, signal messengers and molecular workhorses that underpin living processes in every cell. Understanding when and where proteins are expressed, and their structure and functions, is the realm of proteomics. Mass spectrometry (MS) is a powerful method for identifying and quantifying proteins, however, very large datasets are produced, so researchers rely on computational approaches to transform raw data into protein information. This project develops new bioinformatics solutions to support the next generation of proteomic MS research. Part I introduces the state of the art in proteomic bioinformatics in industry and academia. The business history and funding mechanisms are examined to fill a notable gap in management research literature, and to explain events at the sponsor, GlaxoSmithKline. It reveals that public funding of proteomic science has yet to come to fruition and exclusively high-tech niche bioinformatics businesses can succeed in the current climate. Next, a comprehensive review of repositories for proteomic MS is performed, to locate and compile a summary of sources of datasets for research activities in this project, and as a novel summary for the community. Part II addresses the issue of false positive protein identifications produced by automated analysis with a proteomics pipeline. The work shows that by selecting a suitable decoy database design, a statistically significant improvement in identification accuracy can be made. Part III describes development of computational resources for selecting multiple reaction monitoring (MRM) assays for quantifying proteins using MS. A tool for transition design, MRMaid (pronounced „mermaid‟), and database of pre-published transitions, MRMaid-DB, are developed, saving practitioners time and leveraging existing resources for superior transition selection. By improving the quality of identifications, and providing support for quantitative approaches, this project brings the field a small step closer to achieving the goal of systems biology.
Open Access
Biomimetic sensors for HbA1c
(Cranfield University, 2010-07) Biela, Anna; Piletsky, Sergey A.; Turner, Anthony P. F.
Diabetes mellitus is a growing health problem worldwide. Suitable long-term control and management of this disease are enabled by determination of glycated haemoglobin (HbA1c) in blood. The results are given as %HbA1c of total haemoglobin. Presently available tests vary in cost and convenience and there is an identified need to introduce improved equipment for self-monitoring. This dissertation focuses on fast and straightforward detection of glycated haemoglobin (HbA1c) using cyclic voltammetry and chronoamperometry. Haemoglobin was determined by monitoring its reaction with potassium ferricyanide on screen printed electrodes at an oxidative potential +500 mV. A working electrode was modified with carbon nanotubes to enhance electron transfer. A calibration curve was linear in a range from 0.83 to 83 mg/mL. Another innovative approach to detecting haemoglobin using its enzymatic activity was also developed. Detection of haemoglobin was performed with hydroquinone and hydrogen peroxide on screen printed electrodes at a potential -400 mV in a Flow Injection Analysis system (FIA). Cont/d.
Open Access
Bioremediation of the pesticides Dieldrin, Simazine, Trifluralin using tropical and temperate white-rot fungi
(Cranfield University, 1997-08) Elyassi, Ali; Magan, Naresh
The natural breakdown of three pesticides on the UK Red Lis~ dieldrin~ simazine and trifluralin in water and soil varied with environmental conditions. In both sterile and unsterile water trifluralin was degraded to some extent at 20 and 30°C. In contras~ dieldrin and simazine were stable over the 42 days incubation period. A gradient HPLC method was developed for the simultaneous quantification of the three pesticides in soil. In field capacity soil mixtures of the three pesticides (5 and 10 ppm) showed a similar stability with limited degradation at 20°C but increased rates of degradation at 30°C. At the higher concentration the pesticides naturally degraded at a slower rate. Simazine and trifluralin degradation was significantly enhanced with increasing temperature from 20 to 30°C. Water potential (field capacity~ -0.065 MPa~ and - 0.28 MPa) had little effect on the natural breakdown rate of dieldrin. Simazine showed a greater breakdown in the mid-wetness soil~ while trifluralin was degraded rapidly in the field capacity soil, but not at all in the driest treatment over the 70 day experimental period. In vitro studies on solid agar media overlayed with cellophane showed that of four fungi examined~ Trametes cingulata, Trametes socotrana (tropical species) and Phanerochaete chrysosporium and Polystictus versicolor (temperate species) all except P.chrysosporium were able to grow in the presence of 5 ppm of any of the three pesticides at 20 and 30°C, with the latter only growing at 30°C. At 10 ppm concentration P. chrysosporium did not grow, regardless of temperature or time of incubation (up to 56 days). HPLC was used to quantify the temporal rates of degradation in the solid agar media and this showed that P. versicolor and T. socotrana were very effective at breaking down the three pesticides, at 20 and 30°C. The chosen fungi were grown on chopped straw as a carrier and incorporated into soil microcosms in the ratio of 1:10 containing mixtures of the three pesticides (5, 10 ppm) at 20 and 30°C, and subsequently under different water potential regimes at 20°C only, over periods of 70 days. P. versicolor alone significantly increased breakdown of 5 ppm dieldrin by 26% over untreated controls, while simazine breakdown was increased by 16%. However, for simazine at 30°C there was no difference between temporal rates of natural breakdown and those containing fungal inocula, regardless of concentration. With 5 ppm trifluralin, a maximum breakdown in untreated soil was 67% after 70 days. By contras~ this pesticide was undetectable after 28 days in the presence of the inoculant P . versicolor. This increased to 42 days where a mixture of the two fungi were used. Generally the mixture of fungi used in this study were not as effective in bioremediation of these pesticides as a single species. Field capacity soil appeared to be the best condition for P. versicolor to degrade dieldrin and trifluralin added at 10 ppm. However, for simazine this occurred in the driest water potential (-0.28 MPa) used.