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Modified Materials (modified + material)
Selected AbstractsOrganisation of proficiency testing for plant health diagnostic tests: the experience of FAPAS®EPPO BULLETIN, Issue 1 2010A. Reynolds Proficiency testing (PT) is an established quality assurance measure and is based on the comparison of laboratories' results in an inter-laboratory trial. It highlights problems in laboratory analysis and is an educational tool to help improve data quality. This article describes how PT is organised by FAPAS®. FAPAS® is an international PT provider (external quality assessments) for food chemistry, food microbiology, genetically modified material and water/environmental samples. Since 2007, FAPAS® have organized plant health proficiency tests in conjunction with the Plant Pest and Disease Identification Programme at the Food and Environment Research Agency (Fera). Up until 2009, FAPAS® has organised seven plant health proficiency tests that covered the identification of lyophilised bacteria, viruses in leaves and fungi in agar plugs. In 2009, FAPAS® organized over 10 plant health proficiency tests under the banner of ,PhytoPAS', including Potato spindle tuber viroid, Phytophthora ramorum, Thrips palmi, Erwinia amylovora, Clavibacter michiganensis subsp. sepedonicus, etc. DNA extracts, cyst nematodes (Globodera pallida) and slides/immunofluorescence (IF) slides have been added to the programme. The organization of the plant health proficiency tests follows a similar pattern. Suitable test materials are prepared and tested for quality before distribution to requesting participants. Laboratories usually have 1,2 months to analyze their samples and return their results. A report is then compiled for issue to laboratories and these contain all results in an anonymous form, so that laboratories can compare their results with those of other participants. If a laboratory's performance is unsatisfactory then it is up to them to investigate the situation. Thus, the primary purpose of PT is the detection of inaccuracy in a laboratory's results, so that they can investigate the problems and initiate corrective procedures. [source] Silica-Based, Organically Modified Host Material for Waveguide Structuring by Two-Photon-Induced PhotopolymerizationADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Stefan Krivec Abstract The three-dimensional fabrication of optical waveguides has gained increasing interest in recent years to establish interconnections between electrical components on a very small scale where copper circuits encounter severe limitations. In this work the application of optically clear, organically modified porous silica monoliths and thin films as a host material for polymeric waveguides to be inscribed into the solid host structure by two-photon-induced photopolymerization is investigated. Porosity is generated using a lyotropic liquid crystalline surfactant/solvent system as a template for the solid silica material obtained by a sol,gel transition of a liquid precursor. In order to reduce the brittleness of the purely inorganic material, organic,inorganic co-precursor molecules that contain poly(ethylene glycol) chains are synthesized and added to the mixture, which successfully suppresses macroscopic cracking and leads to flexible thin films. The structure of the thus-obtained porous organic,inorganic hybrid material is investigated by atomic force microscopy. It is shown that the modified material is suitable for infiltration with photocurable monomers and functional polymeric waveguides can be inscribed by selective two-photon-induced photopolymerization. [source] Phosphorus status on Canadian organic farmsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2007Ralph C Martin Abstract In eastern North America, many conventional livestock farms, especially dairy farms with high inputs of feed and fertiliser have excess soil phosphorus levels and an annual phosphorus surplus. However, a Canadian dairy farm in transition to organic, without fertiliser inputs reduced its farm P surplus to a marginal level. On long-term organic dairy farms in Ontario, most soils tested low to very low in available P as measured by a standard soil test. Canadian Prairie organic grain farms also consistently demonstrate deficiencies in available soil P. Organic producers have few viable alternatives for P management. Phosphate rock can be acceptable to organic standards (provided they are low in heavy metals, and not processed synthetically), but the P in these becomes available slowly, especially in high pH soils common on most organic farms in Canada. An alternative is to increase soil P availability. Enhanced microbial activity in organically managed soils may make P more available. Livestock manures are rich sources of available phosphorus, but a majority of organic farmers in Canada do not keep livestock. Off-farm manure sources are subject to organic regulations and hauling costs, both of which may be prohibitive. Furthermore, manure from conventional farms in Canada may be contaminated by genetically modified material from corn and soybean feed. Additional research is required to improve short-term availability of soil P and long-term replacement. Copyright © 2007 Society of Chemical Industry [source] A simple method for detecting genetically modified maize in common food productsBIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION, Issue 1 2004Chris Brinegar Abstract A commercially available leaf DNA extraction and amplification kit has been adapted for the detection of genetically modified material in common food products containing maize. Amplification using published primer pairs specific for the Bacillus thuringiensis delta-endotoxin and maize invertase genes results in a 226-bp invertase PCR product in all samples (an internal positive control) plus a 184-bp product in samples that are genetically modified with the endotoxin gene. The ease and rapidity of DNA extraction and PCR make this exercise especially suitable for advanced-placement high school or lower division college biology students. [source] An evaluation of the self-heating hazards of cerium(IV) nitrated treated towels using differential scanning calorimetry and thermogravimetric analysisFIRE AND MATERIALS, Issue 6 2007J. R. Hartman Abstract This study measured the Arrhenius kinetic parameters and heat of reaction using thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) for the combustion of untreated towels and towels treated with cerium(IV) nitrate. These parameters were used to calculate the self-heating parameters, M and P (Self-heating: Evaluating and Controlling the Hazard. Her Majesty's Stationery Office: London, 1984) and the critical pile sizes of the towels at several temperatures. The results from the TGA/DSC experiments support the conclusions by Beyler et al. (Fire and Materials 2005; 30:223,240) that the cerium(IV) nitrate treatment of towels significantly enhances the ignitability of the towels but that self-heating is not a hazard for normal temperature storage scenarios other than bulk storage. It was found that the kinetic reaction data measured by TGA and DSC are only useful for predicting the specific reaction hazard for materials stored above 100°C. A comparison of the self-heating parameters measured by oven and kinetic reaction data methods for a number of materials suggests that the kinetic reaction data overestimate the critical pile size at temperatures below 100°C. In addition, it was found that the kinetic reaction data measured by TGA can be used to determine the relative self-heating hazards for modified materials. TGA testing with towels saturated with a 0.5 N solution of cerium(IV) nitrate (Ce(NO3)4) in a 2.0 N solution of nitric acid, a 2.0 N solution of sodium nitrate in 2.0 N nitric acid and simple 2.0 N nitric acid, showed that the sodium nitrate and nitric acid treated samples reacted at the same temperatures as the untreated towels, while cerium(IV) nitrate markedly reduced the reaction temperature. These tests clearly point to the importance of the cerium(IV) ion as an oxidizing agent. Thus, the TGA testing provided in a matter of days, insights that would have required months of oven testing. Copyright © 2006 John Wiley & Sons, Ltd. [source] Leading change through an international faculty development programmeJOURNAL OF NURSING MANAGEMENT, Issue 8 2009LORA C. LACEY-HAUN PhD Aims, The purpose of the study was to evaluate the modification of an American model of academic leadership training for utilization in an African university and to pilot test the efficacy of the resulting model. Background, Traditionally many educators have moved into administrative positions without adequate training. Current world standards require leadership preparation for a wide array of persons. However, this opportunity did not yet exist in the study setting. Method, University leaders from the University of the Western Cape and the University of Missouri collaborated on revising and pilot testing a successful American academic leadership programme for use among African faculty. Cross-cultural adaptations, participant satisfaction and subsequent outcomes were assessed during the 2-year ,train-the-trainer' leadership development programme. Results, African faculty successfully modified the American training model, participated in training activities, and after 2 years, began to offer the service to other institutions in the region, which has increased the number of nurses in Africa who have had, and who will continue to have, the opportunity to move up the career ladder. Conclusion, The impact of the project extended further than originally expected, as the original plan to utilize the training materials at the University of the Western Cape (UWC) for the in-house faculty was expanded to allow UWC to utilize the modified materials to serve leadership development needs of faculty in other African universities. Implications for nursing management, Study findings will inform those interested in university policy and procedure on leadership training issues. The successful development of a self-sustaining leadership programme in which values of multiple cultures must be appropriately addressed has a significant impact for nursing administration. With the severe nursing shortage, health care institutions must develop cost effective yet quality development programmes to assure the succession of current staff into leadership positions. We no longer have the luxury of recruiting broadly and we must identify those talented nurses within our own institutions and prepare them for advanced leadership roles. This succession plan is especially important for the next generation of nurse leaders representing minority populations. In particular, nurse managers will find the overview of the literature for middle managers enlightening, and may find links to key resources that could be revised to be more culturally relevant for use in a wide array of settings. [source] A mechanistic investigation into the covalent chemical derivatisation of graphite and glassy carbon surfaces using aryldiazonium saltsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 6 2008Poobalasingam Abiman Abstract Modification of carbon materials such as graphite and glassy carbon in bulk quantities using diazonium salts is developed. We used both 4-nitrobenzenediazonium tetrafluoroborate and 1-antharaquinonediazonium chloride to modify graphite and glassy carbon surfaces. Experiments were carried out in the presence and absence of hypophosphorous acid and the mechanism involved in both cases were studied using cyclic voltammetry. The observed peak potentials for both the 4-nitrophenyl and 1-anthraquinonyl modified materials were found to differ depending on whether or not the hypophosphorous acid reducing agent was used. In the absence of hypophosphorous acid the derivatisation reaction was inferred to go through a cationic intermediate, whilst in the presence of the hypophosphorous acid the mechanism likely involves either a purely radical intermediate or a mixture of radical and cationic species. Derivatisation experiments from 5 to 70°C allowed us to determine the optimum derivatisation temperature for both cases, in the presence and absence of hypophosphorous acid. Optimum temperature was 20°C for the former and 35°C for the later. Copyright © 2008 John Wiley & Sons, Ltd. [source] Effect of an epoxy octasilsesquioxane on the thermodegradation of an epoxy/amine systemPOLYMER INTERNATIONAL, Issue 1 2010Belén Montero Abstract Polyhedral oligomeric silsesquioxanes (POSS®) can be added to thermoplastic and thermostable polymers to obtain hybrid materials with only a minor tendency to suffer ignition. The aim of the work reported was to analyse the influence of an octafunctional POSS® in the pyrolysis of an epoxy/amine system as well as during the combustion process. Thermal degradation of the modified materials, with respect to the unmodified ones, was analysed using thermogravimetric analysis. As the content of POSS® increased the stability improved and the char/ceramic yields were higher. The Kissinger,Akahira,Sunose method was applied to the modified blends and it showed a decrease in the activation energy with POSS® content. Empirical kinetic models, as well as generalized master plots, were applied to explain the degradation mechanism for ternary blends. The limiting oxygen index parameter was measured to analyse the fire retardancy effect of POSS®: it increased from 24.3 to 25.4% with the addition of 2.5 wt% of POSS®. The mechanism of thermal degradation of the hybrid materials based on an epoxy resin is affected by the presence of the octaepoxy POSS®. Only small amounts of POSS® are necessary to enhance the combustion resistance of the system. Copyright © 2009 Society of Chemical Industry [source] Biocompatibility and Calcification of Bovine Pericardium Employed for the Construction of Cardiac Bioprostheses Treated With Different Chemical Crosslink MethodsARTIFICIAL ORGANS, Issue 5 2010Eduardo Jorge-Herrero Abstract The use of biological materials in the construction of bioprostheses requires the application of different chemical procedures to improve the durability of the material without producing any undesirable effects. A number of crosslinking methods have been tested in biological tissues composed mainly of collagen. The aim of this study was to evaluate the in vitro biocompatibility, the mechanical properties, and in vivo calcification of chemically modified bovine pericardium using glutaraldehyde acetals (GAAs) in comparison with glutaraldehyde (GA) treatment. Homsy's tests showed that the most cytotoxic treatment is GA whereas GAA treatments showed lower cytotoxicity. Regarding the mechanical properties of the modified materials, no significant differences in stress at rupture were detected among the different treatments. Zeta-Potential showed higher negative values for GA treatment (,4.9 ± 0.6 mV) compared with GAA-0.625% (,2.2 ± 0.5 mV) and GAA-1% (,2.2 ± 0.4 mV), which presented values similar to native tissue. Similar results were obtained for calcium permeability coefficients which showed the highest values for GA treatment (0.12 ± 0.02 mm2/min), being significantly lower for GAA treatments or non-crosslinked pericardium. These results confirmed the higher propensity of the GA-treated tissues for attraction of calcium cations and were in good agreement with the calcification degree obtained after 60 days implantation into young rats, which was significantly higher for the GA group (22.70 ± 20.80 mg/g dry tissue) compared with GAA-0.625% and GAA-1% groups (0.49 ± 0.28 mg/g dry tissue and 3.51 ± 3.27 mg/g dry tissue, respectively; P < 0.001). In conclusion, GAA treatments can be considered a promising alternative to GA treatment. [source] | ||||||||||||||||