Staff publications - Cranfield Health

Permanent URI for this collection

https://dspace.lib.cranfield.ac.uk/handle/1826/2005

Browse

Now showing 1 - 20 of 122

Open Access
Actions to reduce the impact of construction products on indoor air: outcomes of the European project Healthy Air
(Sage, 2010-06-07T00:00:00Z) Bluyssen, Philomena M.; de Richemont, Sabine; Crump, Derrick; Maupetit, Francois; Witterseh, Thomas; Gajdos, Petr
The European project - HealthyAir is a network project involving six institutions in Europe on actions and activities that address the effects of construction products on indoor air. Different ways to improve indoor air quality were reviewed, ranging from source control to education of occupants on how to manage the built environment to achieve healthy and acceptable indoor air. Through literature study, organised workshops with scientific experts and building professionals as well as via interviews with three stakeholder groups: producers of construction products, architects and housing corporations; requirements for information, guidance and actions to improve indoor air quality were identified. These requirements formed the basis of a possible approach to improve indoor air quality: education and awareness, regulations and policies and further research and development.
Open Access
Application of multiple response optimization design to quantum dot-encoded microsphere bioconjugates hybridization assay
(Elsevier, 2011-07-01) Thiollet, Sarah; Bessant, Conrad M.; Morgan, Sarah L.
The optimization of DNA hybridization for genotyping assays is a complex experimental problem that depends on multiple factors such as assay formats, fluorescent probes, target sequence, experimental conditions, and data analysis. Quantum dot-doped particle bioconjugates have been previously described as fluorescent probes to identify single nucleotide polymorphisms even though this advanced fluorescent material has shown structural instability in aqueous environments. To achieve the optimization of DNA hybridization to quantum dot-doped particle bioconjugates in suspension while maximizing the stability of the probe materials, a nonsequential optimization approach was evaluated. The design of experiment with response surface methodology and multiple optimization response was used to maximize the recovery of fluorescent probe at the end of the assay simultaneously with the optimization of target-probe binding. Hybridization efficiency was evaluated by the attachment of fluorescent oligonucleotides to the fluorescent probe through continuous flow cytometry detection. Optimal conditions were predicted with the model and tested for the identification of single nucleotide polymorphisms. The design of experiment has been shown to significantly improve biochemistry and biotechnology optimization processes. Here we demonstrate the potential of this statistical approach to facilitate the optimization of experimental protocol that involves material science and molecular biology.
Open Access
Ascorbate enhances iron uptake into intestinal cells through formation of a FeCl3-ascorbate complex
(Elsevier Science B.V., Amsterdam., 2010-11-15T00:00:00Z) Thumser, Alfred E.; Rashed, Aswir Abd; Sharp, Paul A.; Lodge, John K.
It has been well documented that ascorbate enhances iron uptake, with a proposed mechanism based on reduction to the more absorbable ferrous form. We have performed a study on the effects of ascorbate on ferric iron uptake in the human epithelial Caco-2 cell-line. Ascorbate increased uptake in a concentration- dependent manner with a significant difference between iron uptake and reduction. Uptake kinetics are characteristic of a non-essential activator and the formation of an Fe3+-ascorbate complex. This investigation provides evidence that ascorbate enhances the apical uptake of ferric iron into Caco-2 cells through the formation of a Fe3+-ascorbate complex. (C) 2010 Elsevier Ltd. All rights reserved.
Open Access
Behavior of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium in teewurst, a raw spreadable sausage
(Elsevier, 2009-04-15) Dourou, Dimitra; Porto-Fett, Anna C. S.; Shoyer, Brad; Call, Jeffrey E.; Nychas, George-John E.; Illg, Ernst K.; Luchansky, John B.
The fate of Listeria monocytogenes, Salmonella Typhimurium, or Escherichia coli O157:H7 were separately monitored both in and on teewurst, a traditional raw and spreadable sausage of Germanic origin. Multi-strain cocktails of each pathogen (ca. 5.0 log CFU/g) were used to separately inoculate teewurst that was subsequently stored at 1.5, 4, 10, and 21 °C. When inoculated into commercially-prepared batter just prior to stuffing, in general, the higher the storage temperature, the greater the lethality. Depending on the storage temperature, pathogen levels in the batter decreased by 2.3 to 3.4, ca. 3.8, and 2.2 to 3.6 log CFU/g for E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, during storage for 30 days. When inoculated onto both the top and bottom faces of sliced commercially-prepared finished product, the results for all four temperatures showed a decrease of 0.9 to 1.4, 1.4 to 1.8, and 2.2 to 3.0 log CFU/g for E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, over the course of 21 days. With the possible exceptions for salt and carbohydrate levels, chemical analyses of teewurst purchased from five commercial manufacturers revealed only subtle differences in proximate composition for this product type. Our data establish that teewurst does not provide a favourable environment for the survival of E. coli O157:H7, S. Typhimurium, or L. monocytogenes inoculated either into or onto the product.
Open Access
Biosensors and nanomaterials and their application for mycotoxin determination
(Wageningen Academic Publishers, 2011-11-01T00:00:00Z) Tothill, Ibtisam E.
Mycotoxin analysis and detection in food and drinks is vital for ensuring food quality and safety, eliminating and controlling the risk of consuming contaminated foods, and complying with the legislative limits set by food authorities worldwide. Most analysis of these toxins is still conducted using conventional methods; however, biosensor methods are currently being developed as screening tools for use in field analysis. Biosensors have demonstrated their ability to provide rapid, sensitive, robust and cost-effective quantitative methods for on-site testing. The development of biosensor devices for different mycotoxins has attracted much research interest in recent years with a range of devices being designed and reported in the scientific literature. However, with the advent of nanotechnology and its impact on the evolution of ultrasensitive devices, mycotoxin analysis is also benefiting from the advances taking place in applying nanomaterials in sensors development. This paper reviews the developments in the area of biosensors and their applications for mycotoxin analysis, as well as the development of micro/nanoarray transducers and nanoparticles and their use in the development of new rapid devices
Open Access
Breath acetone concentration decreases with blood glucose concentration in type I diabetes mellitus patients during hypoglycaemic clamps
(IOP Publishing, 2009-12-02T00:00:00Z) Turner, Claire; Walton, Christopher; Hoashi, Shu; Evans, Mark
Conventional wisdom is that breath acetone may be markedly elevated in type 1 diabetes, but that this only occurs during poor blood glucose control and/or intercurrent illness. In contrast, little is known about breath acetone at more representative everyday blood glucose levels in diabetes. We used selected ion flow tube mass spectrometry to monitor the breath of eight patients with type 1 diabetes mellitus during 'insulin clamp' studies in which insulin and glucose were infused into patients to lower blood glucose levels in steps from normal values into the low glucose (hypoglycaemic) range. The concentration of acetone in breath and the blood sugar concentration of the patients were monitored at each blood glucose concentration. The blood glucose level at the start of the study was typically about 6 mM L-1, whereas the breath acetone concentration at this blood glucose level was unexpectedly variable, ranging from 1 part-per- million to 21 ppm, in contrast to what was previously believed, i.e. that type 1 diabetes mellitus is characterized by high acetone levels. In all eight patients, the breath acetone declined linearly with blood glucose concentration.
Open Access
The burden of cancer at work: estimation as the first step to prevention
(BMJ Publishing Group, 2008-12-31T00:00:00Z) Rushton, L.; Hutchings, S.; Brown, T. P.
Objectives: Work-related cancers are largely preventa¬ble. The overall aim of this project is to estimate the current burden of cancer in Great Britain attributable to occupational factors, and identify carcinogenic agents, industries and occupations for targeting risk prevention. Methods: Attributable fractions and numbers were estimated for mortality and incidence for bladder, lung, non-melanoma skin, and sinonasal cancers, leukaemia and mesothelioma for agents and occupations classified as International Agency for Research on Cancer (IARC) Group 1 and 2A carcinogens with “strong” or “sugges¬tive” evidence for carcinogenicity at the specific cancer site in humans. Risk estimates were obtained from published literature and national data sources used for estimating proportion
Open Access
Catalytic molecularly imprinted polymer membranes: Development of the biomimetic sensor for phenols detection
(Elsevier Science B.V., Amsterdam., 2010-02-05T00:00:00Z) Sergeyeva, T. A.; Slinchenko, O. A.; Gorbach, L. A.; Matyushov, V. F.; Brovko, O. O.; Piletsky, Sergey A.; Sergeeva, L. M.; Elska, G. V.
Portable biomimetic sensor devices for the express control of phenols content in water were developed. The synthetic binding sites mimicking active site of the enzyme tyrosinase were formed in the structure of free-standing molecularly imprinted polymer membranes. Molecularly imprinted polymer membranes with the catalytic activity were obtained by co-polymerization of the complex Cu (II)–catechol–urocanic acid ethyl ester with (tri)ethyleneglycoldimethacrylate, and oligourethaneacrylate. Addition of the elastic component oligourethaneacrylate provided formation of the highly cross-linked polymer with the catalytic activity in a form of thin, flexible, and mechanically stable membrane. High accessibility of the artificial catalytic sites for the interaction with the analyzed phenol molecules was achieved due to addition of linear polymer (polyethyleneglycol Mw 20,000) to the initial monomer mixture before the polymerization. As a result, typical semi-interpenetrating polymer networks (semi-IPNs) were formed. The cross-linked component of the semi-IPN was represented by the highly cross-linked catalytic molecularly imprinted polymer, while the linear one was represented by polyethyleneglycol Mw 20,000. Extraction of the linear polymer from the fully formed semi-IPN resulted in formation of large pores in the membranes’ structure. Concentration of phenols in the analyzed samples was detected using universal portable device oxymeter with the oxygen electrode in a close contact with the catalytic molecularly imprinted polymer membrane as a transducer. The detection limit of phenols detection using the developed sensor system based on polymers–biomimics with the optimized composition comprised 0.063 mM, while the linear range of the sensor comprised 0.063–1 mM. The working characteristics of the portable sensor devices were investigated. Storage stability of sensor systems at room temperature comprised 12 months (87%). As compared to traditional methods of phenols detection the developed sensor system is characterized by simplicity of operation, compactness, and
Open Access
Characterization of industrial onion wastes (Allium cepa L.): dietary fibre and bioactive compounds.
(2011-03-31T00:00:00Z) Benítez, Vanesa; Mollá, Esperanza; Martín-Cabrejas, María A.; Aguilera, Yolanda; López-Andréu, Francisco J.; Cools, Katherine; Terry, Leon A; Esteban, Rosa M.
The food industry produces a large amount of onion wastes, making it necessary to search for possible ways for their utilization. One way could be to use these onion wastes as a natural source of high-value functional ingredients, since onion are rich in several groups of compounds, which have perceived benefits to human health. The objective of this work is to gain knowledge of any differences between the different onion wastes obtained from industry and non-commercial bulbs to use them as food ingredients rich in specific compounds. The results showed that brown skin and top-bottom could be potentially used as functional ingredient rich in dietary fibre, mainly in insoluble fraction, and in total phenolics and flavonoids, with high antioxidant activity. Moreover, brown skin showed a high concentration of quercetin aglycone and calcium, and top-bottom showed high concentration of minerals. Outer scales could be used as source of flavonols, with good antioxidant activity and content of dietary fibre. However, inner scales could be an interesting source of fructans and alk(en)yl cystein sulphoxides. In addition, discarded onions (cvs Recas and Figueres) could be used as a good source of dietary fibre, and cv Recas also as a source of phenolics compounds.
Open Access
Characterization of Langmuir-Blodgett films of a calix[8]arene and sensing properties towards volatile organic vapors
(Elsevier Science B.V., Amsterdam., 2010-07-15T00:00:00Z) Capan, R.; Ozbek, Z.; Goktas, H.; Sen, S.; Ince, F. G.; Ozel, M. E.; Stanciu, G. A.; Davis, Frank
Within this article, we report the characterization and organic vapor sensing properties of Langmuir-Blodgett (LB) thin films of calix[8]arenes. Surface pressure-area isotherms show that very stable monolayers are formed at the air- water interface. The LB film could be deposited onto different substrates which allowed the films to be characterized by UV, quartz crystal microbalance (QCM), surface plasmon resonance (SPR) and atomic force microscopy (AFM). The results indicate that good quality, uniform LB films can be prepared with transfer ratios of over 0.95. QCM results showed that the deposited mass of calix[8]arene monolayer onto a quartz crystal decreased from 693 to 204 ng as the number of layers is increased. AFM studies showed a smooth, and void free surface morphology with a rms value of 1.202 nm. The sensing abilities of this LB film towards the development of room temperature organic vapor sensing devices are also studied. Responses of the LB films to various vapors are fast, large, and reversible. It was found that the obtained LB film is significantly more sensitive to chloroform than other vapors. It can be concluded that this molecule could have a potential application in the research area of room temperature vapor sensing devices. (C) 2010 Elsevier B.V. All rights reserved.
Open Access
A comparison of artificial neural networks and partial least squares modelling for the rapid detection of the microbial spoilage of beef fillets based on Fourier transform infrared spectral fingerprints
(Elsevier Science B.V., Amsterdam, 2011-06-30T00:00:00Z) Panagou, Efstathios Z.; Mohareb, Fady R.; Argyri, Anthoula A.; Bessant, Conrad M.; Nychas, George-John E.
A series of partial least squares (PLS) models were employed to correlate spectral data from FTIR analysis with beef fillet spoilage during aerobic storage at different temperatures (0, 5, 10, 15, and 20°C) using the dataset presented by Argyri etal. (2010). The performance of the PLS models was compared with a three-layer feed-forward artificial neural network (ANN) developed using the same dataset. FTIR spectra were collected from the surface of meat samples in parallel with microbiological analyses to enumerate total viable counts. Sensory evaluation was based on a three-point hedonic scale classifying meat samples as fresh, semi-fresh, and spoiled. The purpose of the modelling approach employed in this work was to classify beef samples in the respective quality class as well as to predict their total viable counts directly from FTIR spectra. The results obtained demonstrated that both approaches showed good performance in discriminating meat samples in one of the three predefined sensory classes. The PLS classification models showed performances ranging from 72.0 to 98.2% using the training dataset, and from 63.1 to 94.7% using independent testing dataset. The ANN classification model performed equally well in discriminating meat samples, with correct classification rates from 98.2 to 100% and 63.1 to 73.7% in the train and test sessions, respectively. PLS and ANN approaches were also applied to create models for the prediction of microbial counts. The performance of these was based on graphical plots and statistical indices (bias factor, accuracy factor, root mean square error). Furthermore, results demonstrated reasonably good correlation of total viable counts on meat surface with FTIR spectral data with PLS models presenting better performance indices compared to ANN.
Open Access
Comparison of different bead-beating RNA extraction strategies: An optimized method for filamentous fungi
(Elsevier Science B.V., Amsterdam., 2012-03-01T00:00:00Z) Leite, Goncalo M.; Magan, Naresh; Medina-Vayá, Ángel
Molecular studies, especially in relation to the activity of secondary metabolite gene clusters, require the ability to extract good quality RNA from fungal biomass. This is often hindered by the cell wall structure and endogenous RNase activity in filamentous fungi. There is thus a need for rapid methods for the extraction of good quality RNA for use in microarrays and for quantitative PCR assays. The objective of this study was to examine the use of different systems for the high throughput method to extract intact RNA from filamentous fungi. Two bead beating systems with different motion patterns and speed capacities were tested in the development of the extraction protocol. They were evaluated based on the total RNA yield and overall RNA quality. The high speed bead beating with glass beads associated with an automated purification method gave more than three times higher total RNA yields with less than a quarter of the amount of mycelium required. Furthermore the integrity and overall quality was conserved, with RNA Quality Indicator (RQI) numbers consistently >7.5. This method also reduced cross contamination risks and kept RNA handling to a minimum while still being capable of multiple sample processing, reducing the time required to obtain RNA from filamentous fungi.
Open Access
Comparison of water activity and temperature impacts on growth of Fusarium langsethiae strains from northern Europe on oat-based media
(Elsevier Science B.V., Amsterdam., 2010-09-01T00:00:00Z) Medina-Vayá, Ángel; Magan, Naresh
This study has examined the effect of water activity (aw, 0.995-0.90) and temperature (10-37Â°C) on the lag phases prior to growth, growth rates and used models to develop two dimensional profiles for optimum and marginal conditions for two strains of Fusarium langsethiae from four northern European countries (UK, Norway, Sweden, and Finland) on an oat-based medium. Results showed that the optimum aw for growth was at 0.98-0.995 and 25Â°C. The limit for growth of the strains was at 0.92-0.93 aw with minima of 10Â°C. No growth occurred at 37Â°C. The lag phases prior to growth were lowest under optimum conditions and extended to >10days at marginal conditions. Statistical analyses of intra and inter- strain differences in terms of both lag phases prior to growth and growth rates were not statistically significant. However, aw and temperature were statistically significant factors. Two dimensional profiles for strains from each country of origin were built to identify optimum and marginal conditions for F. langsethiae for the first time. These environmental profiles will be beneficial for improving the ecological knowledge of this species which is able to produce trichothecene mycotoxins in a range of temperate cereals.
Open Access
Complex regulation of the aflatoxin biosynthesis gene cluster of Aspergillus flavus in relation to various combinations of water activity and temperature
(Elsevier, 2009-11-15) Schmidt-Heydt, Markus; Abdel-Hadi, Ahmed; Magan, Naresh; Geisen, Rolf
A microarray analysis was performed to study the effect of varying combinations of water activity and temperature on the activation of aflatoxin biosynthesis genes in Aspergillus flavus grown on YES medium. Generally A. flavus showed expression of the aflatoxin biosynthetic genes at all parameter combinations tested. Certain combinations of aw and temperature, especially combinations which imposed stress on the fungus resulted in a significant reduction of the growth rate. At these conditions induction of the whole aflatoxin biosynthesis gene cluster occurred, however the produced aflatoxin B1 was low. At all other combinations (25 °C/0.95 and 0.99; 30 °C/0.95 and 0.99; 35 °C/0.95 and 0.99) a reduced basal level of cluster gene expression occurred. At these combinations a high growth rate was obtained as well as high aflatoxin production. When single genes were compared, two groups with different expression profiles in relation to water activity/temperature combinations occurred. These two groups were co-ordinately localized within the aflatoxin gene cluster. The ratio of aflR/aflJ expression was correlated with increased aflatoxin biosynthesis.
Open Access
Computational modeling and molecular imprinting for the development of acrylic polymers with high affinity for bile salts
(Elsevier Science B.V., Amsterdam., 2010-02-05T00:00:00Z) Yañez, Fernando; Chianella, Iva; Piletsky, Sergey A.; Concheiro, Angel; Alvarez-Lorenzo, Carmen
This work has focused on the rational development of polymers capable of acting as traps of bile salts. Computational modeling was combined with molecular imprinting technology to obtain networks with high affinity for cholate salts in aqueous medium. The screening of a virtual library of 18 monomers, which are commonly used for imprinted networks, identified N-(3-aminopropyl)-methacrylate hydrochloride (APMA·HCl), N,N-diethylamino ethyl methacrylate (DEAEM) and ethyleneglycol methacrylate phosphate (EGMP) as suitable functional monomers with medium-to-high affinity for cholic acid. The polymers were prepared with a fix cholic acid:functional monomer mole ratio of 1:4, but with various cross- linking densities. Compared to polymers prepared without functional monomer, both imprinted and non-imprinted microparticles showed a high capability to remove sodium cholate from aqueous medium. High affinity APMA-based particles even resembled the performance of commercially available cholesterol-lowering granules. The imprinting effect was evident in most of the networks prepared, showing that computational modeling and molecular imprinting can act synergistically to improve the performance of certain polymers. Nevertheless, both the imprinted and non-imprinted networks prepared with the best monomer (APMA·HCl) identified by the modeling demonstrated such high affinity for the template that the imprinting effect was less important. The fitting of adsorption isotherms to the Freundlich model indicated that, in general, imprinting increases the population of high affinity binding sites, except when the affinity of the functional monomer for the target molecule is already very high. The cross-linking density was confirmed as a key parameter that determines the accessibility of the binding points to sodium cholate. Materials prepared with 9% mol APMA and 91% mol cross-linker showed enough affinity to achieve binding levels of up to 0.4 mmol g−1 (i.e., 170 mg g−1) under flow (1 mL min−1) of 0.2 mM sodium cholate s
Open Access
Construction and interrogation of enzyme microarrays using scanning electrochemical microscopy - optimisation of adsorption and determination of enzymatic activity.
(Royal Society of Chemistry, 2011-12-21T00:00:00Z) Roberts, William St John; Davis, Frank; Collyer, Stuart D.; Higson, Seamus P. J.
Scanning electrochemical microscopy (SECM) has been used to image and study the catalytic activity of horseradish peroxidase (HRP) immobilised in a patterned fashion onto glass slides. Microarrays of HRP islands could be deposited on amino-modified glass slides using glutaraldehyde crosslinking combined with the SECM being used as a micro-deposition device. The enzymatic activity of the immobilised enzyme on the surface was in the presence of its substrate observed to give rise to substantial positive feedback between the slide and the SECM microelectrode tip. Conversely when either blank slides - or slides coated with HRP which had been subsequently thermally denatured were utilised, these showed negative feedback effects. Various conditions such as enzyme concentration, incubation time and substrate concentration were systematically varied to optimise sensitivity. Regular arrays of HRP could be assembled and when imaged, displayed lower limits of detection of 1.2 × 10(-12) mol ml(-1) of benzoquinone.
Open Access
Contrasting the crystallinity indicators of heated and diagenetically altered bone mineral
(Elsevier, 2010-10-01) Rogers, Keith; Beckett, Sophie; Kuhn, Samira; Chamberlain, Andrew; Clement, John
Modifications to bone mineral as a result of diagenesis or heating include a marked increase in crystallinity. Although these processes are not completely understood a number of simple, pragmatic approaches are in general use to quantify crystallinity and thus provide a relative metric for features such as preservation state. A preliminary investigation into the interpretation of crystallinity as measured by X-ray diffraction has been undertaken. The microstructural changes associated with diagenetically altered (archaeological) and heated contemporary bone have been examined. A common analysis approach was adopted and thus direct comparison between the physical features of these material systems has been possible. The data clearly demonstrate the pronounced anisotropic nature of the crystallite microstructure for both diagenetically altered and contemporary bone. The limitations of adopting simple crystallinity indices for characterising such materials are explored. Crystallite size and strain were shown to be dependent upon crystallographic direction. Overall, the diagenetically altered bone mineral possessed greater long range lattice order than that of contemporary heated bone. Further, significant differences between the directional nature of the microstructure of diagenetically altered and modern heated bone were observed. This study has enabled a direct comparison of the effects of heating and diagenesis upon bone mineral. It has demonstrated the need to consider bone microstructure anisotropically.
Open Access
Control of Aflatoxin Production of Aspergillus flavus and Aspergillus parasiticus Using RNA Silencing Technology by Targeting aflD (nor-1) Gene.
(MDPI , 2011-06-30T00:00:00Z) Abdel-Hadi, Ahmed; Caley, D. P.; Carter, D. R.; Magan, Naresh
Aspergillus ﬂavus and Aspergillus parasiticus are important pathogens of cotton, corn, peanuts and other oil-seed crops, producing toxins both in the field and during storage. We have designed three siRNA sequences (Nor-Ia, Nor-Ib, Nor-Ic) to target the mRNA sequence of the aflD gene to examine the potential for using RNA silencing technology to control aflatoxin production. Thus, the effect of siRNAs targeting of two key genes in the aflatoxin biosynthetic pathway, aflD (structural) and aflR (regulatory gene) and on aflatoxin B(1 )(AFB(1)), and aflatoxin G(1) (AFG(1)) production was examined. The study showed that Nor-Ib gave a significant decrease in aflD mRNA, aflR mRNA abundance, and AFB(1) production (98, 97 and 97% when compared to the controls) in A. flavus NRRL3357, respectively. Reduction in aflD and aflR mRNA abundance and AFB(1 )production increased with concentration of siRNA tested. There was a significant inhibition in aflD and AFB(1) production by A. flavus EGP9 and AFG(1 )production by A. parasiticus NRRL 13005. However, there was no significant decrease in AFG(1) production by A. parasiticus SSWT 2999. Changes in AFB(1) production in relation to mRNA levels of aflD showed a good correlation (R = 0.88; P = 0.00001); changes in aflR mRNA level in relation to mRNA level of aflD also showed good correlation (R = 0.82; P = 0.0001). The correlations between changes in aflR and aflD gene expression suggests a strong relationship between these structural and regulatory genes, and that aflD could be used as a target gene to develop efficient means for aflatoxin control using RNA silencing technolog
Open Access
Controlled release of the herbicide simazine from computationally designed molecularly imprinted polymers
(Elsevier Science B.V., Amsterdam., 2005-11-02T00:00:00Z) Piletska, Elena V.; Turner, Nicholas W.; Turner, Anthony P. F.; Piletsky, Sergey A.
The present study describes the development of materials suitable for environmental control of algae. Molecularly imprinted polymers (MIPs) were used as simazine carriers able to provide the controlled release of simazine into water. Three polymers were designed using computational modelling. The selection of methacrylic acid (MA) and hydroxyethyl methacrylate (HEM) as functional monomers was based on results obtained using the Leapfrog™ algorithm. A cross- linked polymer made without functional monomers was also prepared and tested as a control. The release of simazine from all three polymers was studied. It was shown that the presence of functional monomers is important for polymer affinity and for controlled release of herbicide. The speed of release of herbicide correlated with the calculated binding characteristics. The high-affinity MA- based polymer released 2% and the low-affinity HEM-based polymer released 27% of the template over 25 days. The kinetics of simazine release from HEM-based polymer show that total saturation of an aqueous environment could be achieved over a period of 3 weeks and this corresponds to the maximal simazine solubility in water. The possible use of these types of polymers in the field of controlled release is discusse
Open Access
Current trends in explosive detection techniques
(Elsevier Science B.V., Amsterdam., 2012-01-15T00:00:00Z) Caygill, J. S.; Davis, Frank; Higson, Seamus P. J.
The detection of explosives and explosive-related compounds has become a heightened priority in recent years for homeland security and counter-terrorism applications. There has been a huge increase in research within this area- through both the development of new, innovative detection approaches and the improvement of existing techniques. Developments for miniaturisation, portability, field-ruggedisation and improvements in stand-off distances, selectivity and sensitivity have been necessary to develop and improve techniques. This review provides a consolidation of information relating to recent advances in explosive detection techniques without being limited to one specific research area or explosive type. The focus of this review will be towards advances in the last 5 years, with the reader being referred to earlier reviews where appropriate.