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Добірка наукової літератури з теми "Solid matrices"

Автор: Grafiati

Опубліковано: 8 лютого 2025

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Статті в журналах з теми "Solid matrices"

Das, A. "Metal speciation in solid matrices." Talanta 42, no. 8 (August 1995): 1007–30. http://dx.doi.org/10.1016/0039-9140(95)01557-r.

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Ramasamy, Savakkattupalayam M., and Robert J. Hurtubise. "Comparative Study of the Solid-Matrix Luminescence Properties of Perdeuterated Phenanthrene and Phenanthrene Adsorbed on Several Solid Matrices." Applied Spectroscopy 50, no. 9 (September 1996): 1140–44. http://dx.doi.org/10.1366/0003702963905196.

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Temperature was varied over a wide range to determine its effect on the luminescence properties of deuterated phenanthrene and phenanthrene adsorbed on a number of solid matrices. Not only were insights into the effects of temperature and solid matrices on the luminescence properties acquired but also the deuterium isotope effect revealed unique information about the role played by the solid matrix in the luminescence of the model compounds. In addition, comparisons of nonradiative rate constants and the efficiencies of intersystem crossing revealed important differences among the solid matrices in altering these parameters. The perdeuterated phenanthrene and phenanthrene proved to be useful probes for investigating the effects of solid matrices on the excited triplet state of phosphors because the excited singlet state of the lumiphor was affected very little by the solid matrices, and the rate constants of phosphorescence for the two phosphors are essentially the same.

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Lubach, Joseph W., Brian E. Padden, Stephanie L. Winslow, Jonathon S. Salsbury, David B. Masters, Elizabeth M. Topp, and Eric J. Munson. "Solid-state NMR studies of pharmaceutical solids in polymer matrices." Analytical and Bioanalytical Chemistry 378, no. 6 (March 1, 2004): 1504–10. http://dx.doi.org/10.1007/s00216-003-2381-4.

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Fu, Y. C., C. H. Tong, and D. B. Lund. "Moisture Migration in Solid Food Matrices." Journal of Food Science 68, no. 8 (October 2003): 2497–503. http://dx.doi.org/10.1111/j.1365-2621.2003.tb07051.x.

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Rendón-Castrillón, Leidy, Margarita Ramírez-Carmona, Carlos Ocampo-López, and Luis Gómez-Arroyave. "Bioleaching Techniques for Sustainable Recovery of Metals from Solid Matrices." Sustainability 15, no. 13 (June 28, 2023): 10222. http://dx.doi.org/10.3390/su151310222.

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This review paper explores the potential of bioleaching as a sustainable alternative for recovering metals from solid matrices. With over 12 billion tons of solid waste annually worldwide, bioleaching provides a promising opportunity to extract metals from solid waste, avoiding harmful chemical processes. It explains bacterial and fungal bioleaching techniques that extract copper, gold, zinc, and other metals from solid matrices. Fungal bioleaching effectively extracts a wide range of valuable metals, including nickel, vanadium, aluminium, molybdenum, cobalt, iron, manganese, silver, platinum, and palladium. The review highlights different solid matrices with metal contents that have the potential to be recovered by bioleaching, presenting promising bioprocess alternatives to current industrially available technologies for metal recovery. The optimal conditions for bioleaching, including pH, temperature, agitation–aeration, and pulp density are also discussed. The review shows that bioleaching has the potential to play a crucial role in the transition to a more sustainable and circular economy by providing an efficient, cost-effective, and environmentally friendly method for metal recovery from solid matrices.

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Sassi, Guido, Marco Bernocco, and Mariapaola Sassi. "Uncertainty of the Diffusion Measurements on Scaffolds for Cell Growth." Defect and Diffusion Forum 312-315 (April 2011): 770–75. http://dx.doi.org/10.4028/www.scientific.net/ddf.312-315.770.

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The regenerative medicine uses gel and porous solid matrices as scaffolds for the growth of the stem cells in 3D structures. The structural and fluid dynamic properties of the matrices have been recognized to highly affect the behaviour and functions of the cells. The procedures of production and the clinical use of the matrices need a reliable and reproducible characterization of their properties, this means that the concepts of metrology must be applied to the measurement and definition of all the relevant properties. This paper deals with the calculation of uncertainty for diffusivity measurement in solids and the role of uncertainty in designing the measurement. Diffusion of a solute in spherical solid particles dispersed in a limited liquid volume where considered as measurement method for a Ca-alginate polymer. The model sensitivity to the concentration measurements, the model parameters and the fitting procedures have been discussed.

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Naccarato, Attilio, and Antonio Tagarelli. "Advances in Solid-Phase Microextraction." Separations 7, no. 2 (June 12, 2020): 34. http://dx.doi.org/10.3390/separations7020034.

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Zwittnig, Katharina, Barbara Kirnbauer, Norbert Jakse, Peter Schlenke, Irene Mischak, Shahram Ghanaati, Sarah Al-Maawi, Dániel Végh, Michael Payer, and Tomislav A. Zrnc. "Growth Factor Release within Liquid and Solid PRF." Journal of Clinical Medicine 11, no. 17 (August 29, 2022): 5070. http://dx.doi.org/10.3390/jcm11175070.

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Aim: The purpose of this study was to obtain data concerning growth factor release within liquid and solid platelet-rich fibrin (PRF) matrices and to estimate the amount of potential interindividual variations as a basis for further preclinical and clinical trials. Therefore, we aimed to determine possible differences in the release of growth factors between liquid and solid PRF. Materials and Methods: Blood samples obtained from four subjects were processed to both liquid and solid PRF matrices using a standard centrifugation protocol. Five growth factors (vascular endothelial growth factor, VEGF; epidermal growth factor, EGF; platelet-derived growth factor-BB, PDGF-BB; transforming growth factor-β1, TGF-β1; and matrix metallopeptidase 9, MMP-9) have been evaluated at six time points by ELISA over a total observation period of 10 days (1 h, 7 h, 1 d, 2 d, 7 d, and 10 d). Results: Growth factor release could be measured in all samples at each time point. Comparing liquid and solid PRF matrices, no significant differences were detected (p > 0.05). The mean release of VEGF, TGFβ-1, PDGF-BB, and MMP-9 raised to a peak at time point five (day 7) in both liquid and solid PRF matrices. VEGF release was lower in liquid PRF than in solid PRF, whereas those of PDGF-BB and MMP-9 were higher in liquid PRF than in solid PRF at all time points. EGF had its peak release already at time point two after 7 h in liquid and solid matrices (hour 7 EGF solid: mean = 180 pg/mL, SD = 81; EGF liquid: mean = 218 pg/mL, SD = 64), declined rapidly until day 2, and had a second slight peak on day 7 in both groups (day 7 EGF solid: mean = 182 pg/mL, SD = 189; EGF liquid: mean = 81 pg/mL, SD = 70). Conclusions: This study detected growth factor release within liquid and solid PRF matrices with little variations. Further preclinical trials are needed to precisely analyze the growth factor release in larger samples and to better understand their effects on wound healing in different clinical indications.

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Marialva-Neto, A. A., Sandra Maria Cunha, Antônio Carlos da Silva, and Sonia Regina Homem de Mello-Castanho. "Solid Galvanic Wastes Incorporation in Glass Matrices." Materials Science Forum 498-499 (November 2005): 500–505. http://dx.doi.org/10.4028/www.scientific.net/msf.498-499.500.

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Among the industrial solid residues, the galvanic wastes have been received special attention, due to the nature of its components. These residues in general present a high concentration of alkaline and transition metals. When discarded or stored inadequately, they can be released for the environment, causing ecological and health damages. An interesting alternative to recycle those wastes is to remove them from the environment, through its incorporation in silicate glasses matrices. This work proposes the obtaining of amorphous structures, glasses or frits, from formulations with industrial solid galvanic wastes, with good chemical stability. A characterization study of the residue and primary materials, as commercial silica and feldspar and investigations about the formation of amorphous phases, galvanic wastes incorporation and chemical stability of the obtained products, were made. With these results, it was possible to formulate compositions that allow the obtaining of frits for ceramic enamels, with 23 % in weight of solid galvanic waste incorporated and good coating characteristics.

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Bentivegna, Florian, Michael Canva, Patrick Georges, Alain Brun, Frédéric Chaput, Laurent Malier, and Jean‐Pierre Boilot. "Reverse saturable absorption in solid xerogel matrices." Applied Physics Letters 62, no. 15 (April 12, 1993): 1721–23. http://dx.doi.org/10.1063/1.109585.

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Більше джерел

Дисертації з теми "Solid matrices"

Gudmundsdóttir, Anna Dóra. "Photochemistry of some naphthoquinols in solid polymer matrices." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27471.

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The main objective of this work was to study how polymer media can modify the photochemical reactivity of dissolved guest molecules. Three tetrahydronaphthoquinols, whose photochemistry is known to be sensitive to the reaction medium, were synthesized for this study. The photochemistry of these compounds consisted of [2 + 2] cycloaddition in solution and hydrogen abstraction-initiated rearrangement in the solid state. Different photopro-ducts from solution and solid state photolysis were interpreted as being due to reaction from different conformers in the different media. 2,3,4aα,6,7,8aα-hexamethyl-4a,5,8,8a-tetrahydronaphthoquin- l-on-4β-ol, studied in poly(methyl methacrylate) and poly(vinyl acetate) films, was found to exhibit behavior that is intermediate to solution and solid state reactivity and is discontinuous at the glass transition temperature. 2,3,4aα,6,7,8aα-hexamethyl-4a,5,8,8a-tetrahydronaphthoquin-l-on-4α-ol, which was essentially unreactive in the solid state, was also studied. It was found to give the expected but not observed solid state product as the major product in poly(methyl methacrylate). Finally, 2 , 3 ,4aα ,6,7, 8aα:-4a ,5,8, 8a- tetrahydronaphthoquin-1-on-4β-acetate was studied. As a result of differences in the local enviroment, this compound displayed unique photoreactivity in each of three different media: in solution it gave 5-exo-acetoxy-l,3,4,6,8,9-hexamethyltetracyclo [4.4.0.0[sup 3,9].0[sup 4,8]decan-2-one, in the pure crystalline phase it gave 5-exo-acetoxy-2-oxy-1,3,4,6,8,9-hexamethyltricyclo[4.4.0.0[sup 4,7]-dec-8-en -2-one and in poly(methyl methacrylate) films 5-exo-acetoxy-1,3,4,6,8,9-hexamethyltetracyclo[4.4.0.0[sup 3,7]dec-8-en-2-one, as a major product. It has been demonstrated that polymer matrices are useful reaction media for reducing the rates of conformational interconversions to the point that alternative chemical processes that are normally too slow to be observed in solution become competitive. This leads to chemical consequences that in some cases mimic those observed in the solid state. In others, where crystals are unreactive for some reasons or where the crystal lattice can sterically impede certain reactions, new products can be formed.
Science, Faculty of
Chemistry, Department of
Graduate

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Burk, Robert C. (Robert Charles) Carleton University Dissertation Chemistry. "Supercritical fluid extraction of trace organics from solid matrices." Ottawa, 1990.

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McLean, Alan Stuart. "Transfer matrices and image transport in random media." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307659.

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Lopes, Lidia Velazquez. "Sorption of the platinum-group elements in selected solid matrices." Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/4210.

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Summary in English.
Bibliography: leaves 70-75.
Recent research on the platinum-group elements (PGE) has shown increased concentrations in environmental samples, probably as a result of the widespread use of PGE (Pt, Pd and Rh in particular) as catalysts in the chemical and car industry. Most of the recent research on PGE focuses on the analysis of concentrations in environmental samples exposed to anthropogenic sources of PGE, but there are very few studies that have investigated sorption behaviour of PGE in soils.

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Chan, Wai-Chan. "Development of liquid crystalline materials as matrices for polymer composites." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334122.

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Lee, Myung-hyun. "Optoelectronic properties of small silver particles embedded in non-metallic matrices." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314890.

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Phillips, Justin. "Dextrin nanocomposites and deep eutectic solvents as matrices for solid dosage forms." Diss., University of Pretoria, 2020. http://hdl.handle.net/2263/81724.

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Controlled-release formulations for pesticide applications act as depot systems that continuously release the active ingredients into the environment over a speci ed period, usually from months to years. However, some applications require fast-dissolving drug delivery. The interest of this research is in fast-release of water-insoluble pesticides into aquatic environments. This study considered the use of dextrin starch and urea eutectics as fast release, solid dosage carrier forms that contain an active ingredient. The chosen active for this study is an acaricide called amitraz (N-methylbis-(2,4-xylyliminomethyl)- methylamine). The focus is on matrix-based dosage forms such as tablets, granules or bres that either disintegrate or dissolve to release a water-insoluble active. These types of dosage forms can be fabricated using processes such as lyophilisation, spray drying, solvent casting, hot melt extrusion, compression moulding, wet granulation, compaction and electrospinning. A simple melt-casting procedure has been discussed in the present work. Dextrin is a water-soluble form of partially hydrolysed starch and is a promising candidate matrix material for dissolving solid dosage forms. The molecular weight of the dextrin was analysed with MALDI-TOF methods and rheological relations. Glycerolplasticized thermoplastic dextrin-based nanocomposites were prepared with a twin-screw extrusion-compounding process. The nano llers included a layered double hydroxide (LDH), cellulose nano bres (CNF) and stearic acid. The time-dependent retrogradation of the compounds was monitored by X-ray di raction (XRD) and dynamic mechanical thermal analysis (DMA). XRD showed that the inclusion of stearic acid in the formulations led to the formation of an amylose-lipid complex and a stable crystallinity during ageing. Dissolution rates in water for samples containing dextrin starch, were characterised using an iodine indicator and UV-visible spectroscopy. High pressure di erential scanning calorimetry (HPDSC) indicated that the addition of stearic acid led to the formation of amylose-lipid complexes (ALC's). An additive system containing stearic acid and CNF was deemed suitable for compounding with amitraz. Compounding at temperatures above the melting point of the latter led, on dissolution in water, to the release of much ner particles of the acaricide, which was con rmed with particle size analysis (PSA). The addition of the acaricide caused an apparent increase in the dissolution rate of the thermoplastic dextrin. Two eutectic urea systems were considered for casting with amitraz. A eutectic system of urea and acetamide was found to display a melting point of 44 C at a 37 wt.% urea composition. The other system consisting of urea and 1,3-dimethylurea displayed a eutectic point at 32 wt.% urea composition which melted at 59 C. Di erential scanning calorimetry (DSC), however, con rmed a melting point depression due to a high moisture content caused by the compounds high hygroscopicity. The endotherm of the sample containing no excess moisture showed a melting point of 70 C. The 1,3-dimethylurea system was deemed suitable for casting with amitraz. XRD of the eutectic composition indicated a small amount of co-crystallisation. The samples were cast as disks of various diameters while keeping the height of the disks constant. The creation of the cast disks showed automatic generation of a nely dispersed form of the active through the process of melting the deep eutectic solvent, the dissolution of the active and its phase separation on cooling and solidi cation of the eutectic. This implies that ne grinding of the actives might not be necessary. Eutectic casts containing 20 wt.% amitraz dissolved at a slower rate than casts not containing the hydrophobic active ingredient. The advantageous features of these casts were exempli ed using the acaricide incorporated into the urea & 1,3-dimethylurea eutectic. This work provides two safe, biodegradable and water soluble materials for use as a matrix to contain active ingredients. One material, the eutectic organic salt casts, can be produced at low temperatures (<100 C) and can be directly cast into storage containers. The complete dissolution of the cast compounded with a hydrophilic active is rapid (4-6 min). The second material, a thermoplastic dextrin, was melt compounded in an extruder at temperatures not exceeding 120 C. This compound containing 20 wt.% of the active dissolved over a 12 hour period. Dextrin, known to be widely used as an adhesive, will aid in the adhesion of the active ingredient to the surface where it must be used.
Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2019.
PAMSA
Department of Science and Innovation under Grant DST/CON 0004/2019
Chemical Engineering
MEng (Chemical Engineering)
Unrestricted

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Ntola, Chifundo Nyasha Michelle. "Solid lipid matrices for delivery of laundry actives and lipid membrane transport." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12027/.

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The work presented in this thesis reports the preparation and characterisation of novel solid lipid microparticle (SLM) and solid lipid nanoparticle (SLN) systems for applications in delivery of laundry actives and transport of electroactive substances into lipid membranes. The SLM and SLN systems studied are: silicone-loaded SLM, dye-loaded SLM, dual-active SLM (both silicone and dye) and ferrocene-loaded SLN (Fc-SLN). Silicones are used as fabric softeners in laundry applications and dyes are used to enhance the hue of fabrics. The incorporation of two actives into one, dual-active SLM, is a concept that could enable compact formulation and optimized formulation manufacture. The ferrocene-loaded SLN system represent the group of electroactive nanoparticles that could potentially find applications in biosensors, targeted delivery and other biomedical applications. The SLM and SLN systems were prepared using lauric acid as the lipid matrix. Silicone-loaded SLM systems were prepared using solvent-assisted methods with either ethanol or n-hexane as the solvent. They were stabilized with a combination of a primary alcohol ethoxylate (C14-15) (neodol 45-7) and polysorbate 80 (tween 80) as surfactant/co-surfactant). The silicones used were: polydimethylsiloxane (PDMS)(10,000 cST and 100,000 cSt), terminal amino-functionalised silicone (TAS) and a tertiary amino-functionalised silicone (PK10). The dye-loaded SLM systems, incorporating Coomassie Brilliant Blue R (CBB or BB) and ethyl violet (EV, Basic Violet 4) as hueing dyes were prepared using the double emulsion method, also descriptively known as the water-in-oil-in-water (w/o/w) emulsion method. The inner emulsion, w/o was stabilized using a low HLB surfactant, Brij 80 and the outer emulsion o/w was stabilized using a high HLB surfactant, tween 80. For the dual-active SLM system, PK10 silicone was added to the lipid phase before emulsification. The Fc-SLN system was prepared using the solvent emulsification/evaporation method. The surfactants used were poloxamer 188 and tween 80. The lipid membrane systems used were: solid-supported self-assembled monolayer (SAM) and tethered bilayer lipid membrane. The SAM was prepared by chemisorption of a thiolipid, 1,2-dipalmitoyl-sn-glycero-phosphothioethanol (DPPTE) onto a gold surface. Self-assembled monolayers were used as a lower leaflet or tether for the BLM system; an upper leaflet of 1-palmitoyl-2-oloeyl-sn-glycero-3-phosphocholine (POPC) was added by vesicle fusion. The characterisation and penetration of Fc-SLN into lipid membranes was studied using electrochemical methods such as cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and Resonance Enhanced Surface Impedance (RESI). The SLM and SLN systems where characterised using laser diffraction and dynamic light scattering (DLS) for particle size analysis, optical microscopy and electron microscopy for morphology and particle size, small angle X-Ray Scattering (SAXS) and differential scanning calorimetry (DSC) for crystallinity and structural arrangement and chemical analysis using FTIR, solid state NMR and TGA.

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Cooper, Gail Audrey Ann. "Application of solid-phase extraction for the analysis of drugs in biological matrices." Thesis, University of Glasgow, 1999. http://theses.gla.ac.uk/5368/.

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Experimental mixed-mode solid-phase extraction columns of differing carbon number and carbon loading were investigated for the efficient extraction of drugs of abuse from biological matrices. Methadone and its two major metabolites (EDDP and EMDP) were chosen due to the increase in methadone drug-related deaths in the West of Scotland. Amphetamine and related compounds (methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methyleneidoxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA)) were chosen because of the prevalence of use of "speed" and "ecstasy" throughout the United Kingdom and the challenge these volatile drugs pose to the analyst. Improved methods were developed for the efficient extraction of methadone, EDDP and EMDP from whole blood and for amphetamine and related compounds from whole blood and hair. These methods were successfully applied to the analysis of postmortem samples. The stability of methadone, EDDP and EMDP in whole blood was investigated using the developed extraction method after sorting at various temperatures for a period of six months. Methadone remained stable in blood after six months. This was confirmed by the analysis of postmortem cases samples which when re-analysed within six months of the initial analysis, correlated well. Postmortem hair samples proved useful for determining antecedent drug use history whether extracted by solid-phase extraction or after screening with a Cohort enzyme immunoassay kit, adapted for hair analysis. Solid-phase extraction provides a clean and efficient means of extracting drugs of abuse from whole blood and hair. Simple manipulation of the extraction system (sample pretreatment, pH, derivatisation) provides a versatile alternative to lengthy liquid-liquid extraction techniques and has the added potential of automation.

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van, Rensburg Wilma. "Characterization of natural antimicrobial peptides adsorbed to different matrices." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97929.

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Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Biofouling is the attachment and biofilm formation that leads to negative repercussions such as persistent post-harvest infections, infections obtained from medical implants and continual surface contamination of food processing plants. Much of the problem lies with the resistance that develops against conventional treatments due to the formation of mature biofilms. Thus the focus has shifted from the removal of biofilms to the prevention of initial attachment of organisms. This entails the use of antimicrobial surfaces that either have an inherent antimicrobial activity, e.g. certain metals, or surfaces that are modified by the attachment of antimicrobial agents. The attachment of antimicrobial agents can either be through covalent bonding or adsorption, depending on the intended use of the surface as well as the mode of action of the antimicrobial agent. Antimicrobial peptides (AMPs) are ubiquitous in nature, tend to have a broad spectrum of activity, are very stable and have been shown to maintain activity when covalently bound to solid surfaces. Tyrocidines (Trcs), antimicrobial peptides produced by Bacillus aneurinolyticus, are cyclodecapeptides with a broad spectrum of activity against Grampositive bacteria, fungi, yeasts and the human malaria parasite, Plasmodium falciparum. The aim of this study was to determine the antimicrobial activity of surfaces treated with a tyrocidine extract, under which conditions the activity remained stable and to look into possible applications of these peptide-treated surfaces. The study focussed on different solid surfaces namely mixed cellulose, polyvinylidene fluoride, polycarbonate, cellulose acetate, cellulose (paper)(CL) and high density cellulose packing material (HDC), as a pilot study to assess the antimicrobial activity of Trc and gramicidin S (GS) treated solid surfaces. Peptide desorption and subsequent analysis by mass spectrometry was used to confirm the presence and integrity of the Trcs adsorbed. Scanning electron microscopy was utilised to show that the adsorbed peptides did not affect the structural integrity of the treated filters. However, it was shown that the adsorbed peptides changed the hydrophobic/hydrophilic character by means of a wettability assay. A cell viability assay and erythrocyte assay were developed from existing methodologies to determine the biological activity of the AMP-functionalised polymeric material. Seven of the AMP treated solid surfaces showed antimicrobial activity when challenged with >105 Micrococcus luteus cells/cm2. Although the polycarbonate filter lost antimicrobial activity at the high cell concentrations, it was shown to have potent antimicrobial activity at lower cell concentrations. Complete inhibition of M. luteus growth was observed for both the gramicidin S and tyrocidine extract treated high density cellulose and cellulose filters. Stability tests showed that the tyrocidines remained adsorbed to cellulose filters and biologically active when exposed multiple water washes, water washes at different temperatures (25°C - 100°C) and pH changes (pH 1-12). The antimicrobial activity was only affected after exposure to the water wash of pH 13 which is possible due to susceptibility of the CL filters to high pH solvents. A preliminary study on the effect of Trcs treated CL filters on the sterilization, germination and effect on tomato seedlings was conducted. It was found that Trcs had no effect on the germination and did not fully sterilise the seeds or environment against fungi. However, it was observed that 5 μg/mL Trcs treated filters promoted root length opposed to the toxic effect seen with filters treated with higher Trc concentrations. It is hypothesised that Trcs prefer to bind to hydrophilic surfaces exposing the hydrophobic residues and the cationic residue of the peptide to interact with the bacterial membrane to elicit its antimicrobial response. The exposed residues contain some of the hydrophobic residues and the cationic Orn9/Lys9, which are crucial to the antimicrobial activity of the peptides. Hydrophobic interaction is particularly important for the haemolytic activity which is currently the only viable method of detection of the adsorbed Trcs. Trcs also have a preference for adsorption onto cellulose and cellulose analogues which points to possible application in protective food wrapping and wood surface protection. Trcs maintains its antimicrobial activity regardless of adsorption to solid surfaces. It can therefore be concluded that Trcs treated solid surfaces hold great potential in preventing the initial bacterial colonization and subsequent biofilm formation. Antimicrobial peptide enriched solid surfaces can thus be developed and tailored to a specific application such as filters, catheters and packaging materials.
AFRIKAANSE OPSOMMING: Biovervuiling is die aanhegting en vorming van biofilms met negatiewe gevolge soos aanhoudende na-oes infeksies, infeksies op mediese inplantings en voortdurende oppervlak besoedeling van voedselverwerkings fabrieke. Die probleem lê grotendeels by die weerstand wat ontwikkel word teen konvensionele behandelings as gevolg van die vorming van volwasse biofilms. Die fokus het gevolglik verskuif vanaf die verwydering van biofilms na die voorkoming van aanvanklike aanhegting van organismes aan oppervlaktes. Dit behels die gebruik van antimikrobiese oppervlaktes wat of 'n inherente antimikrobiese aktiwiteit het, bv. sekere metale óf oppervlaktes wat aangepas is deur die aanhegting van antimikrobiese middels. Die aanhegting van antimikrobiese agente kan of deur kovalente binding óf adsorpsie plaasvind, afhangende van die beoogde gebruik van die oppervlak, sowel as die metode van werking van die antimikrobiese agent. Antimikrobiese peptiede (AMPe) is alomteenwoordig in die natuur, is geneig om 'n breë spektrum van aktiwiteit te hê, is baie stabiel en het getoon dat aktiwiteit in stand gehou word wanneer dit kovalent gebind word op soliede oppervlaktes. Tirosidiene (Trcs), antimikrobiese peptiede wat deur Bacillus aneurinolyticus geproduseer word, is siklodekapeptiede met 'n breë spektrum van aktiwiteit teen Gram-positiewe bakterieë, swamme, giste en die menslike malaria parasiet Plasmodium falciparum. Die doel van hierdie studie was om die antimikrobiese aktiwiteit te bepaal van oppervlaktes wat met 'n tirosidien ekstrak behandel is, te bepaal onder watter omstandighede die aktiwiteit stabiel bly en om te soek na moontlike toepassings van hierdie peptied-behandelde oppervlaktes. Die studie het gefokus op verskillende soliede oppervlaktes naamlik gemengde sellulose, polyvinylidene fluoried, polikarbonaat, sellulose asetaat, sellulose (papier)(CL) en 'n hoë digtheid sellulose verpakkings materiaal (HDC), as 'n loodsstudie om die antimikrobiese aktiwiteit van die Trcs en gramisidien S (GS) behandelde soliede oppervlaktes te ondersoek. Peptied-desorpsie en daaropvolgende ontleding deur massaspektroskopie is gebruik om die teenwoordigheid en integriteit van die geadsorbeerde Trcs te bevestig. Skandering elektronmikroskopie is gebruik om aan te toon dat die geadsorbeerde peptiede geen invloed op die strukturele integriteit van die behandelde filters het nie. Daar is egter getoon dat die geadsorbeerde peptiede die hidrofobiese / hidrofiliese karakter verander. „n Lewensvatbaarheid selgebaseerde toets en eritrosiet toets is ontwikkel uit bestaande metodes om die biologiese aktiwiteit van die AMP-gefunktionaliseerde polimeriese materiaal te bepaal. Sewe van die AMP behandel soliede oppervlaktes het antimikrobiese aktiwiteit getoon wanneer dit met > 105 Micrococcus luteus selle/cm2 gedaag is. Hoewel die polikarbonaat filter antimikrobiese aktiwiteit met hoë sel konsentrasies verloor het, is dit getoon dat dit wel uitgeproke antimikrobiese aktiwiteit het teen laer konsentrasies selle. Volledige inhibisie van M. luteus groei is waargeneem vir beide die hoë digtheid sellulose en sellulose filters wat met GS en tirosidien ekstrak behandel is. Stabiliteit toetse het getoon dat die tirosidiene geadsorbeer en biologies aktief op sellulose filters bly nadat dit blootgestel is aan verskeie water was-stappe, waterwasse by verskillende temperature (25 °C -100 °C) en pH veranderinge (pH 1-12). Die antimikrobiese aktiwiteit was net beïnvloed ná blootstelling aan die water met 'n pH 13, wat moontlik is te danke aan die vatbaarheid van die CL filters by hoë pH oplosmiddels is. 'n Voorlopige studie is gedoen om die uitwerking van Trcs behandelde CL filters op die sterilisasie, ontkieming en tamatiesaailinge te bepaal. Daar is gevind dat Trcs geen effek op die ontkieming het nie, maar dat dit nie volledig die sade en omgewing steriliseer vir fungiese groei nie. Daar is egter waargeneem dat 5 μg/mL Trcs behandelde filters wortel lengte van die saailinge bevorder teenoor die giftige uitwerking soos waargeneem vir die filters wat met hoër konsentrasies Trcs behandel is. Dit word gepostuleer dat Trcs verkies om aan hidrofiliese oppervlaktes te bind wat die van die hidrofobiese aminosure en die kationiese residu van die peptied blootstel om aan die bakteriële membraan te bind om gevolglik antimikrobiese reaksie te ontlok. Die blootgestelde deel bevat sommige van die hidrofobiese residue en positiewe Orn9/Lys9 wat noodsaaklik vir die antimikrobiese aktiwiteit van die peptiede. Die hidrofobiese interaksies is veral belangrik vir die hemolitiese aktiwiteit wat tans die enigste bruikbare metode van opsporing van die geadsorbeerde Trcs is. Trcs het ook 'n tendens vir adsorpsie op sellulose en sellulose analoë wat dui op die moontlike toepassing in beskermende voedselverpakking en die beskerming van houtoppervlaktes. Trcs handhaaf hul antimikrobiese aktiwiteit, ongeag van adsorpsie aan soliede oppervlaktes. Dit kan dus afgelei word dat Trcs-behandelde soliede oppervlaktes die potensiaal het om die aanvanklike kolonisasie van bakterië te voorkom en die daaropvolgende biofilm vorming. Antimikrobiese peptied verrykde soliede oppervlaktes kan dus ontwikkel en aangepas word vir gebruik in spesifieke toepassing soos in filters, kateters en verpakkingsmateriaal.

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Книги з теми "Solid matrices"

Centi, Gabriele, Blanka Wichterlová, and Alexis T. Bell, eds. Catalysis by Unique Metal Ion Structures in Solid Matrices. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0782-5.

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Tindal, R. Investigations of photophysical parameters of luminescent reagents in solutions and in solid matrices. Manchester: UMIST, 1995.

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I, Gidopoulos N., and Wilson S. 1950-, eds. The fundamentals of electron density, density matrix, and density functional theory in atoms, molecules, and the solid state. Dordrecht: Kluwer Academic Publishers, 2003.

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D, Messman J., and Environmental Monitoring Systems Laboratory (Research Triangle Park, N.C.), eds. Determination of stable valence states of chromium in aqueous and solid waste matrices: Experimental verification of chemical behavior. Cincinnati, OH: U.S. Environmental Protection Agency, Environmental Monitoring Systems Laboratory, 1986.

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Karlsson, Hans O. Atomic and molecular density-of-states by direct Lanczos methods. Uppsala: Acta Universitatis Upsaliensis, 1994.

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Wichterlová, Blanka, Alexis T. Bell, and Gabriele Centi. Catalysis by Unique Metal Ion Structures in Solid Matrices: From Science to Application. Springer, 2012.

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(Editor), N. I. Gidopoulos, and S. Wilson (Editor), eds. The Fundamentals of Electron Density, Density Matrix and Density Functional Theory in Atoms, Molecules and the Solid State (Progress in Theoretical Chemistry and Physics). Springer, 2003.

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(Editor), Gabriele Centi, Blanka Wichterlová (Editor), and Alexis T. Bell (Editor), eds. Catalysis by Unique Metal Ion Structures in Solid Matrices: From Science to Application (NATO Science Series II: Mathematics, Physics and Chemistry). Springer, 2001.

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Mindes, Gayle. Teaching Young Children Social Studies. Praeger, 2006. http://dx.doi.org/10.5040/9798216023340.

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By linking theory to practice with an emphasis on national and state standards, Head Start Performance Standards, No Child Left Behind, and IDEA, the authors coherently combine principles of child development and social studies content to create a solid program for preschool through grade three. The authors maintain the overriding idea throughout theTeaching Young Childrenseries—that strategies derived from knowledge of child development are used to teach content knowledge. It is this concern that makes this volume an excellent resource for teachers and parents. In addition to specific discussions of how to build and conduct a social studies curriculum, the work includes vignettes of teachers and children in the classroom; graphics illustrating concepts and methods; and matrices, charts and tables to enhance understanding. The authors effectively intertwine social learning in young children and development of self-concept with the theme-based curriculum of the National Council for Social Studies, the principles of multicultural education, parent collaboration to support learning, and creating connections between classroom and community.

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Crisanti, Andrea, Giovanni Paladin, and Angelo Vulpiani. "Why Study Random Matrices?" In Springer Series in Solid-State Sciences, 3–15. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84942-8_1.

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Musto, Pellegrino, Michele Galizia, Giuseppe Scherillo, and Giuseppe Mensitieri. "Water Sorption Thermodynamics in Polymer Matrices." In Solid Mechanics and Its Applications, 15–45. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-7417-9_2.

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Wong, S. S., K. P. Wirth, and F. W. Röllgen. "Sputtering from Liquid and Solid Organic Matrices." In Springer Proceedings in Physics, 91–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82718-1_18.

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Marialva-Neto, A. A., S. M. Cunha, A. C. Silva, and Sonia R. H. Mello Castanho. "Solid Galvanic Wastes Incorporation in Glass Matrices." In Advanced Powder Technology IV, 500–505. Stafa: Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/0-87849-984-9.500.

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Telepchak, Michael J., Thomas F. August, and Glynn Chaney. "Separation of Analytes from Their Matrices." In Forensic and Clinical Applications of Solid Phase Extraction, 129–46. Totowa, NJ: Humana Press, 2004. http://dx.doi.org/10.1007/978-1-59259-292-0_7.

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Mackenzie, K., M. Remmler, and F. D. Kopinke. "Reductive Dehalogenation of Organohalogens Fixed on Solid Matrices." In Contaminated Soil ’95, 1289–90. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0421-0_117.

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Bayona, J. M. "Off-line supercritical fluid extraction for solid matrices." In Analytical Supercritical Fluid Extraction Techniques, 72–108. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-4948-8_3.

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Kou, Dawen, and Somenath Mitra. "Extraction of Semivolatile Organic Compounds from Solid Matrices." In Sample Preparation Techniques in Analytical Chemistry, 139–82. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2003. http://dx.doi.org/10.1002/0471457817.ch3.

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Giliopoulos, Dimitrios J., Kostas S. Triantafyllidis, and Dimitrios Gournis. "Chemical Functionalization of Carbon Nanotubes for Dispersion in Epoxy Matrices." In Solid Mechanics and Its Applications, 155–83. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-4246-8_5.

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Audit, Philippe. "Use of Cyclic Matrices to Obtain Analytic Expressions for Crystals." In Springer Series in Solid-State Sciences, 91–101. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-82444-9_9.

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Тези доповідей конференцій з теми "Solid matrices"

Gugliermino, M., D. O. Rodriguez-Duarte, S. Garino, S. Corallo, C. Origlia, J. A. Tobon Vasquez, R. Scapaticci, L. Crocco, and F. Vipiana. "Comparative Assessment of Electro-Mechanical and Solid-State Switching Matrices for a Portable Microwave (pMWI) Scanner in Brain Imaging Applications." In 2024 International Conference on Electromagnetics in Advanced Applications (ICEAA), 1. IEEE, 2024. http://dx.doi.org/10.1109/iceaa61917.2024.10701957.

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Bagnich, Sergey A. "Migration of benzaldehyde triplet-excitation in porous matrices." In Tunable Solid State Lasers, edited by Wieslaw Strek, Edward Lukowiak, and Barbara Nissen-Sobocinska. SPIE, 1997. http://dx.doi.org/10.1117/12.293450.

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Marczak, Rogério, and Bruno Vieceli. "Optimization of Fiber Paths Embedded in Elastomeric Matrices." In 9th International Symposium on Solid Mechanics. ABCM, 2024. http://dx.doi.org/10.26678/abcm.mecsol2024.msl24-0199.

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Syskakis, E., Y. Fujii, M. Gebhardt, and F. Pobell. "Specific heat of liquid 3He bubbles in solid matrices." In Symposium on quantum fluids and solids−1989. AIP, 1989. http://dx.doi.org/10.1063/1.38832.

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Yariv, Eli, Renata Reisfeld, and Aryeh M. Weiss. "Optical nonlinearities of methyl red in various solid matrices." In 8th Meeting in Israel on Optical Engineering, edited by Moshe Oron, Itzhak Shladov, and Yitzhak Weissman. SPIE, 1993. http://dx.doi.org/10.1117/12.151130.

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Su, Syang Y., William J. Long, Andrae K. Spencer, and Tae J. Chung. "Some Studies In Solid Matrices And Facile Micellar Luminescence." In 1988 Los Angeles Symposium--O-E/LASE '88, edited by E. R. Menzel. SPIE, 1988. http://dx.doi.org/10.1117/12.945447.

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Starukhin, A. S., Alexander M. Shulga, Valentin N. Knyukshto, Jerzy Sepiol, R. Kolos, Alois Renn, and Urs P. Wild. "Single-molecule spectroscopy of molecules isolated in solid-deposited matrices." In XVII International Conference on Coherent and Nonlinear Optics (ICONO 2001), edited by Andrey Y. Chikishev, Valentin A. Orlovich, Anatoly N. Rubinov, and Alexei M. Zheltikov. SPIE, 2002. http://dx.doi.org/10.1117/12.468885.

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Starukhin, A., and M. Kruk. "Spectral manifestation of distorted forms of metalloporphins in solid matrices." In The International Conference on Coherent and Nonlinear Optics, edited by Sergey A. Tikhomirov, Thomas Udem, Valery Yudin, Maxim Pshenichnikov, and Oleg M. Sarkisov. SPIE, 2007. http://dx.doi.org/10.1117/12.752500.

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Aldag, H. R., D. P. Pacheco, S. M. Dolotov, M. F. Koldunov, V. Reznichenko, Y. V. Kravchenko, A. A. Manenkov, and G. P. Reskova. "Polymer-filled microporous glass matrices for efficient solid-state dye lasers." In Conference on Lasers and Electro-Optics (CLEO 2000). Technical Digest. Postconference Edition. TOPS Vol.39. IEEE, 2000. http://dx.doi.org/10.1109/cleo.2000.907205.

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Abedin, Kazi Monowar, Ye Jing Yong, Hideyuki Inouye, Toshiaki Hattori, and Hiroki Nakatsuka. "Local Dynamics in Solid Matrices Investigated by Malachite Green Optical Microprobes." In Spectral Hole-Burning and Related Spectroscopies: Science and Applications. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/shbs.1994.wd33.

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Dynamics of molecules or molecular constituents doped in amorphous systems is recently of considerable interest. In these systems, it is important to know how rigidly the doped molecules (guest) are bound to the surrounding polymer matrix. The nature of the guest-matrix interaction, on which this rigidity depends, is not so well understood at present. The motion of the doped molecules or their constituents is influenced by the surrounding matrix. Molecular motions having no appreciable internal potential barrier, are ideal probes of matrix rigidity, since matrix friction or viscosity is the only impediment to the motion of molecules or molecular constituents in these cases.

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Звіти організацій з теми "Solid matrices"

Crouch, Rebecca, Jared Smith, Bobbi Stromer, Christian Hubley, Samuel Beal, Guilherme Lotufo, Afrachanna Butler, et al. Methods for simultaneous determination of legacy and insensitive munition (IM) constituents in aqueous, soil/sediment, and tissue matrices. Engineer Research and Development Center (U.S.), August 2021. http://dx.doi.org/10.21079/11681/41720.

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Currently, no standard method exists for analyzing insensitive munition (IM) compounds in environmental matrices, with or without concurrent legacy munition compounds, resulting in potentially inaccurate determinations. The primary objective of this work was to develop new methods of extraction, pre-concentration, and analytical separation/quantitation of 17 legacy munition compounds along with several additional IM compounds, IM breakdown products, and other munition compounds that are not currently included in U.S. Environmental Protection Agency (EPA) Method 8330B. Analytical methods were developed to enable sensitive, simultaneous detection and quantitation of the 24 IM and legacy compounds, including two orthogonal high-performance liquid chromatography (HPLC) column separations with either ultraviolet (UV) or mass spectrometric (MS) detection. Procedures were developed for simultaneous extraction of all 24 analytes and two surrogates (1,2-dinitrobenzene, 1,2-DNB; o-NBA) from high- and low-level aqueous matrices and solid matrices, using acidification, solid phase extraction (SPE), or solvent extraction (SE), respectively. The majority of compounds were recovered from four tissue types within current limits for solids, with generally low recovery only for Tetryl (from 4 to 62%). A preparatory chromatographic interference removal procedure was adapted for tissue extracts, as various analytical interferences were observed for all studied tissue types.

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LaVerne, Jay A. Hazardous Gas Production by Alpha Particles in Solid Organic Transuranic Waste Matrices. Office of Scientific and Technical Information (OSTI), June 1999. http://dx.doi.org/10.2172/828402.

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Tam, Simon, Mario E. Fajardo, Hiroyuki Katsuki, Hiromichi Hoshina, and Takamasa Momose. High Resolution Infrared Absorption Spectra of Methane Molecules Isolated in Solid Parahydrogen Matrices. Fort Belvoir, VA: Defense Technical Information Center, May 1999. http://dx.doi.org/10.21236/ada408708.

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Lippert, T., D. J. Funk, C. E. M. Strauss, and P. O. Stoutland. Picosecond infrared spectroscopy as probe for photochemical or thermal reactions in solid matrices. Office of Scientific and Technical Information (OSTI), August 1998. http://dx.doi.org/10.2172/638215.

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LaVerne, J. A. Hazardous gas production by alpha particles in solid organic transuranic waste matrices. 1998 annual progress report. Office of Scientific and Technical Information (OSTI), June 1998. http://dx.doi.org/10.2172/13650.

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Crouch, Rebecca, Jared Smith, Bobbi Stromer, Christian Hubley, Samuel Beal, Guilherme Lotufo, Afrachanna Butler, et al. Preparative, extraction, and analytical methods for simultaneous determination of legacy and insensitive munition (IM) constituents in aqueous, soil or sediment, and tissue matrices. Engineer Research and Development Center (U.S.), August 2021. http://dx.doi.org/10.21079/11681/41480.

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No standard method exists for determining levels of insensitive munition (IM) compounds in environmental matrices. This project resulted in new methods of extraction, analytical separation and quantitation of 17 legacy and 7 IM compounds, daughter products of IM, and other munition compounds absent from USEPA Method 8330B. Extraction methods were developed for aqueous (direct-injection and solid-phase extraction [SPE]), soil, sediment, and tissue samples using laboratory-spiked samples. Aqueous methods were tested on 5 water sources, with 23 of 24 compounds recovered within DoD QSM Ver5.2 limits. New solvent extraction (SE) methods enabled recovery of all 24 compounds from 6 soils within QSM limits, and a majority of the 24 compounds were recovered at acceptable levels from 4 tissues types. A modified chromatographic treatment method removed analytical interferences from tissue extracts. Two orthogonal high-performance liquid chromatography-ultraviolet (HPLC-UV) separation methods, along with an HPLC–mass spectrometric (HPLC-MS) method, were developed. Implementing these new methods should reduce labor and supply costs by approximately 50%, requiring a single extraction and sample preparation, and 2 analyses rather than 4. These new methods will support environmental monitoring of IM and facilitate execution of risk-related studies to determine long-term effects of IM compounds.

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Stromer, Bobbi, Rebecca Crouch, Katrinka Wayne, Ashley Kimble, Jared Smith, and Anthony Bednar. Methods for simultaneous determination of 29 legacy and insensitive munition (IM) constituents in aqueous, soil-sediment, and tissue matrices by high-performance liquid chromatography (HPLC). Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/1168142105.

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Standard methods are in place for analysis of 17 legacy munitions compounds and one surrogate in water and soil matrices; however, several insensitive munition (IM) and degradation products are not part of these analytical procedures. This lack could lead to inaccurate determinations of munitions in environmental samples by either not measuring for IM compounds or using methods not designed for IM and other legacy compounds. This work seeks to continue expanding the list of target analytes currently included in the US Environmental Protection Agency (EPA) Method 8330B. This technical report presents three methods capable of detecting 29 legacy, IM, and degradation products in a single High Performance Liquid Chromatography (HPLC) method with either ultraviolet (UV)-visible absorbance detection or mass spectrometric detection. Procedures were developed from previously published works and include the addition of hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX); hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX); hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX); 2,4-diamino-6-nitrotoluene (2,4-DANT); and 2,6-diamino-4-nitrotoluene (2,6-DANT). One primary analytical method and two secondary (confirmation) methods were developed capable of detecting 29 analytes and two surrogates. Methods for high water concentrations (direct injection), low-level water concentrations (solid phase extraction), soil (solvent extraction), and tissue (solvent extraction) were tested for analyte recovery of the new compounds.

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Irudayaraj, Joseph, Ze'ev Schmilovitch, Amos Mizrach, Giora Kritzman, and Chitrita DebRoy. Rapid detection of food borne pathogens and non-pathogens in fresh produce using FT-IRS and raman spectroscopy. United States Department of Agriculture, October 2004. http://dx.doi.org/10.32747/2004.7587221.bard.

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Rapid detection of pathogens and hazardous elements in fresh fruits and vegetables after harvest requires the use of advanced sensor technology at each step in the farm-to-consumer or farm-to-processing sequence. Fourier-transform infrared (FTIR) spectroscopy and the complementary Raman spectroscopy, an advanced optical technique based on light scattering will be investigated for rapid and on-site assessment of produce safety. Paving the way toward the development of this innovative methodology, specific original objectives were to (1) identify and distinguish different serotypes of Escherichia coli, Listeria monocytogenes, Salmonella typhimurium, and Bacillus cereus by FTIR and Raman spectroscopy, (2) develop spectroscopic fingerprint patterns and detection methodology for fungi such as Aspergillus, Rhizopus, Fusarium, and Penicillium (3) to validate a universal spectroscopic procedure to detect foodborne pathogens and non-pathogens in food systems. The original objectives proposed were very ambitious hence modifications were necessary to fit with the funding. Elaborate experiments were conducted for sensitivity, additionally, testing a wide range of pathogens (more than selected list proposed) was also necessary to demonstrate the robustness of the instruments, most crucially, algorithms for differentiating a specific organism of interest in mixed cultures was conceptualized and validated, and finally neural network and chemometric models were tested on a variety of applications. Food systems tested were apple juice and buffer systems. Pathogens tested include Enterococcus faecium, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus, Yersinia enterocolitis, Shigella boydii, Staphylococus aureus, Serratiamarcescens, Pseudomonas vulgaris, Vibrio cholerae, Hafniaalvei, Enterobacter cloacae, Enterobacter aerogenes, E. coli (O103, O55, O121, O30 and O26), Aspergillus niger (NRRL 326) and Fusarium verticilliodes (NRRL 13586), Saccharomyces cerevisiae (ATCC 24859), Lactobacillus casei (ATCC 11443), Erwinia carotovora pv. carotovora and Clavibacter michiganense. Sensitivity of the FTIR detection was 103CFU/ml and a clear differentiation was obtained between the different organisms both at the species as well as at the strain level for the tested pathogens. A very crucial step in the direction of analyzing mixed cultures was taken. The vector based algorithm was able to identify a target pathogen of interest in a mixture of up to three organisms. Efforts will be made to extend this to 10-12 key pathogens. The experience gained was very helpful in laying the foundations for extracting the true fingerprint of a specific pathogen irrespective of the background substrate. This is very crucial especially when experimenting with solid samples as well as complex food matrices. Spectroscopic techniques, especially FTIR and Raman methods are being pursued by agencies such as DARPA and Department of Defense to combat homeland security. Through the BARD US-3296-02 feasibility grant, the foundations for detection, sample handling, and the needed algorithms and models were developed. Successive efforts will be made in transferring the methodology to fruit surfaces and to other complex food matrices which can be accomplished with creative sampling methods and experimentation. Even a marginal success in this direction will result in a very significant breakthrough because FTIR and Raman methods, in spite of their limitations are still one of most rapid and nondestructive methods available. Continued interest and efforts in improving the components as well as the refinement of the procedures is bound to result in a significant breakthrough in sensor technology for food safety and biosecurity.

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Belkin, Shimshon, Sylvia Daunert, and Mona Wells. Whole-Cell Biosensor Panel for Agricultural Endocrine Disruptors. United States Department of Agriculture, December 2010. http://dx.doi.org/10.32747/2010.7696542.bard.

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Objectives: The overall objective as defined in the approved proposal was the development of a whole-cell sensor panel for the detection of endocrine disruption activities of agriculturally relevant chemicals. To achieve this goal several specific objectives were outlined: (a) The development of new genetically engineered wholecell sensor strains; (b) the combination of multiple strains into a single sensor panel to effect multiple response modes; (c) development of a computerized algorithm to analyze the panel responses; (d) laboratory testing and calibration; (e) field testing. In the course of the project, mostly due to the change in the US partner, three modifications were introduced to the original objectives: (a) the scope of the project was expanded to include pharmaceuticals (with a focus on antibiotics) in addition to endocrine disrupting chemicals, (b) the computerized algorithm was not fully developed and (c) the field test was not carried out. Background: Chemical agents, such as pesticides applied at inappropriate levels, may compromise water quality or contaminate soils and hence threaten human populations. In recent years, two classes of compounds have been increasingly implicated as emerging risks in agriculturally-related pollution: endocrine disrupting compounds (EDCs) and pharmaceuticals. The latter group may reach the environment by the use of wastewater effluents, whereas many pesticides have been implicated as EDCs. Both groups pose a threat in proportion to their bioavailability, since that which is biounavailable or can be rendered so is a priori not a threat; bioavailability, in turn, is mediated by complex matrices such as soils. Genetically engineered biosensor bacteria hold great promise for sensing bioavailability because the sensor is a live soil- and water-compatible organism with biological response dynamics, and because its response can be genetically “tailored” to report on general toxicity, on bioavailability, and on the presence of specific classes of toxicants. In the present project we have developed a bacterial-based sensor panel incorporating multiple strains of genetically engineered biosensors for the purpose of detecting different types of biological effects. The overall objective as defined in the approved proposal was the development of a whole-cell sensor panel for the detection of endocrine disruption activities of agriculturally relevant chemicals. To achieve this goal several specific objectives were outlined: (a) The development of new genetically engineered wholecell sensor strains; (b) the combination of multiple strains into a single sensor panel to effect multiple response modes; (c) development of a computerized algorithm to analyze the panel responses; (d) laboratory testing and calibration; (e) field testing. In the course of the project, mostly due to the change in the US partner, three modifications were introduced to the original objectives: (a) the scope of the project was expanded to include pharmaceuticals (with a focus on antibiotics) in addition to endocrine disrupting chemicals, (b) the computerized algorithm was not fully developed and (c) the field test was not carried out. Major achievements: (a) construction of innovative bacterial sensor strains for accurate and sensitive detection of agriculturally-relevant pollutants, with a focus on endocrine disrupting compounds (UK and HUJ) and antibiotics (HUJ); (b) optimization of methods for long-term preservation of the reporter bacteria, either by direct deposition on solid surfaces (HUJ) or by the construction of spore-forming Bacillus-based sensors (UK); (c) partial development of a computerized algorithm for the analysis of sensor panel responses. Implications: The sensor panel developed in the course of the project was shown to be applicable for the detection of a broad range of antibiotics and EDCs. Following a suitable development phase, the panel will be ready for testing in an agricultural environment, as an innovative tool for assessing the environmental impacts of EDCs and pharmaceuticals. Furthermore, while the current study relates directly to issues of water quality and soil health, its implications are much broader, with potential uses is risk-based assessment related to the clinical, pharmaceutical, and chemical industries as well as to homeland security.

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