Solid Phase Microextraction (SPME) associated with Microwave Assisted Extraction (MAE)^(1-3) , on-line headspace derivatization ^(4-6) and the selectivity of different SPME coatings ⁽⁷⁾ were studied. Trace amounts of Veltol ®, Veltol Plus® and short chain fatty acids in food samples were analyzed by GC/MS. Since SPME is not directly applicable to solid samples, SPME associated with MAE techniques was studied for solids, primarily food samples. The efficiency of classical solvent extraction and MAE was compared. The parameters which affect SPME, were optimized for the determination of Veltol® and Veltol Plus® in food products such as potato chips and coffee. The technique gave a detection limit of 2 ppb for Veltol Plus ® which is 200 times more sensitive than conventional GC technique. Headspace injection is characterized by simple and easy handling of complicated solid and solution matrices. Headspace injection, however, is not suitable for high molecular weight substances or non-volatile compounds. An on-line derivatization headspace technique was studied for short chain fatty acids. These samples are difficult to do by classical GC. The developed technique simplified the conventional derivatization procedures and combined the sample preparation and GC/MS analysis into one step. The thermostatting temperature, time, solvent and matrix effects were investigated. Low calorie fat and some agricultural samples were analyzed. The detection limit for acetic acid is 8 ppb. SPME is a novel sample introduction technique. The behavior of di(methylsiloxane), polyacrylate and Carbowax coatings on SPME fibers for compounds having different functional groups were investigated. The selectivities of the coating, sample pH and the sample temperature were investigated. / Ph. D.

The extraction and recovery of trace organic material from semi-solid and solid matrices is often the slowest and most error-prone step of an analytical method. The conventional liquid extraction techniques for solids and semi-solids materials (Soxhlet) have two main disadvantages. The first, large volumes of organic solvent are required, which can lead to sample contamination and "losses" due to volatilization during concentration steps. The second, to achieve an exhaustive extraction can require several hours to days. With the development of sophisticated instrumentation with detection limits in the picogram and femtogram levels, pressure is finally felt within the analytical community to develop and validate sample preparation procedures which can be used to rapidly isolate trace level organics from complex matrices.Because of its applicability to solid, semi-solid, and liquid matrices microwave-assisted (MAE) extraction has emerged as a powerful sample preparation technique. The objective of this research was to evaluate directly focused microwave energy for the isolation of systemic fungicide residues from woody plant tissues.The hallmark of microwave extraction (MAE) is accelerated dissolution kinetics as a consequence of the rapid heating processes that occur when a microwave field is applied to a sample. The current popularity of MAE resides mainly on its applicability to a wide range of sample types because the selectivity can be easily manipulated by altering solvent polarities.Propiconazole is a systemic fungicide, used to combat the fungal pathogen Ophiostoma ulmi, the casual agent of Dutch elm disease (DED). It was successfully extracted from treated Ulmus americana (elm tree) using MAE with a percent recovery of 395% in 15 minutes. Until now, techniques for rapid and efficient extraction of polar material from wood were non-existent. This work produces results much quicker than Supercritical Fluid Extraction (SFE). The influence of pH, microwave power, and time on extraction efficiency was also investigated. The extraction methodology was optimized and statistically validated.This MAE method combined with GC-MS was used to study the diffusion patterns and degradation of propiconazole in tree bark over extended time periods. Because of the complex nature of woody plant systems, it was realized that a more theoretical means must be used to determine the degradation rate of propiconazole in water systems. As a result, propiconazole was reacted with water under controlled temperature and pH conditions; to measure the degradation rate of propiconazole.The internal pH of elm sap is about 6.0; the slightly acidic environment and natural enzymes within the xylem vessels are known to catalyze the degradation of propiconazole (1). Novartis Inc. has marketed propiconazole as having fungicidal effects in injected elms for nearly two years. Our degradation studies have indicated much shorter lifetimes. To confirm our fate studies, the activation energy for the degradation reaction of propiconazole was calculated. This information provided valuable insight into revising dosage and treatment frequency for maximum protection of the elm against Dutch elm disease. Anti-fungal activity among metabolites was also explored. This is the first reported use of MAE to monitor the degradation of systemic pesticides in woody plant material. / Ph. D.

Made available in DSpace on 2014-12-17T14:07:20Z (GMT). No. of bitstreams: 1 RoseaneAB.pdf: 1493954 bytes, checksum: 6a4a785122e4795a117a7d18bbd1666c (MD5) Previous issue date: 2007-03-26 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Metallic tantalum has a high commercial value due to intrinsic properties like excellent ductility, corrosion resistance, high melt and boiling points and good electrical and thermal conductivities. Nowadays, it is mostly used in the manufacture of capacitors, due to excellent dielectric properties of its oxides. In the nature, tantalum occurs in the form of oxide and it is extracted mainly from tantalite-columbite ores. The tantalum is usually produced by the reduction of its oxide, using reductants like carbon, silicon, calcium, magnesium and aluminum. Among these techniques, the aluminothermic reduction has been used as the industrial method to produce niobium, tantalum and their alloys, due to the easy removal of the Al and Al2O3 of the system, easing further refining. In conventional aluminothermic reduction an electrical resistance is used to trigger the reaction. This reaction self-propagates for all the volume of material. In this work, we have developed a novel technique of aluminothermic reduction that uses the hydrogen plasma to trigger the reaction. The results obtained by XRD, SEM and EDS show that is possible to obtain a compound rich in tantalum through this technique of aluminothermic reduction in the plasma reactor / O t?ntalo ? um metal de elevado valor comercial devido suas propriedades intr?nsecas como excelente ductilidade, resist?ncia ? corros?o, elevados pontos de fus?o e ebuli??o e boas condutividades t?rmica e el?trica. Atualmente sua maior aplica??o tem sido na produ??o de capacitores, devido ?s excelentes propriedades diel?tricas de seus ?xidos. Na natureza o t?ntalo ocorre na forma de ?xido e ? extra?do principalmente do min?rio tantalita-columbita. O p? de t?ntalo met?lico ? normalmente produzido pela redu??o do seu ?xido, utilizando agentes redutores tais como carbono, sil?cio, c?lcio, magn?sio e o alum?nio. Dentre estas t?cnicas, a aluminotermia vem sendo utilizada como m?todo industrial para a produ??o do ni?bio, t?ntalo e suas ligas, em virtude da f?cil remo??o do alum?nio (Al) e da alumina (Al2O3) do sistema, o que facilita a etapa de refino. No processo de aluminotermia convencional ? utilizado um elemento resistivo como ignitor da rea??o, que se auto-propaga para todo o volume de material. No presente trabalho foi desenvolvida uma t?cnica de aluminotermia que utiliza o plasma de hidrog?nio como ignitor da rea??o. Os resultados obtidos por DRX, MEV e EDS mostram que ? poss?vel a obten??o de um concentrado rico em t?ntalo pela t?cnica de redu??o aluminot?rmica a plasma

L'arsenic est un élément présent dans tous les compartiments de l'environnement, et les produits de la pêche représentent une source majeure d'exposition à l'arsenic par le biais de l'alimentation. Même s'il n'existe pas à ce jour de législation sur les teneurs en arsenic dans les aliments en France, les agences gouvernementales évaluent généralement les risques liés à la présence d'arsenic dans les produits de la pêche en se basant essentiellement sur la concentration totale de l'élément, sans tenir compte des différentes espèces présentes ni de leur bioaccessibilité. Par conséquent, le développement de méthodes d'analyse de spéciation revêt un intérêt particulier dans le cadre de l'évaluation des risques. La première partie de ce mémoire présente des informations générales sur les propriétés de l'arsenic, son occurrence dans les différents compartiments de l'environnement et sa toxicité, ainsi qu'une étude bibliographique des méthodes analytiques existantes pour étudier la spéciation de l'arsenic dans les matrices alimentaires, en particulier les produits de la pêche (extraction et séparation/détection). Les différentes approches pour l'évaluation de sa bioaccessibilité et de celle d'autres éléments traces métalliques d'intérêt sont également présentées. La deuxième partie de ces travaux porte sur la validation d'une méthode d'analyse de spéciation des principales espèces d'arsenic dans les produits la pêche (As(III), MA,DMA, As(V), AsB, TMAO, AsC) par couplage entre la chromatographie d'échange d'ions (IEC) et la spectrométrie de masse à plasma induit (ICP-MS) après extraction assistée par micro-ondes (MAE). L'évaluation des performances analytiques de la méthode, les contrôles qualités internes et externes mis en place et les différentes applications, en particulier les données d'occurrence des différentes espèces d'arsenic dans les produits de la pêche les plus consommés par la population française sont présentés et discutés. Dans la troisième partie, la bioaccessibilité maximale de l'arsenic et d'autres éléments d'intérêt est estimée à l'aide d'une méthode de lixiviation en ligne (impliquant la mesure en temps réel par ICP-MS de la fraction libérée par les différents fluides digestifs artificiels). La combinaison de ce procédé avec la méthode d'analyse de spéciation validée permet ainsi d'estimer la bioaccessibilité des différentes espèces d'arsenic. / Arsenic is an element present in all compartments of the environment, and seafood constitutes a major source of exposure to arsenic through human consumption. Although there is currently no legislation on arsenic in food in France, government agencies generally assess the safety of food items based solely on the total concentration of the element, without taking into account its different species or their bioaccessibility. Therefore, the development of speciation analysis methods is particularly relevant in the context of risk assessment. The first part of this thesis focuses on the properties of arsenic, its occurrence in the different compartments of the environment and its toxicity, and a literature review of existing analytical methods to study the speciation of arsenic in food matrices, especially seafood products (extraction and separation / detection). Different approaches for evaluating its bioaccessibility and that of other trace metals of interest are also presented.The second part of this work concerns the validation of a speciation analysis method for major arsenic species in seafood (As (III), MA, DMA, As (V), AsB, TMAO, AsC) by coupling ion exchange chromatography (IEC) with inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted extraction (MAE). Evaluation of the analytical performance of the method, internal and external quality controls in place and applications of the method, particularly occurrence data of arsenic species in seafood most consumed by the French population are presented and discussed. In the third part, the maximum bioaccessibility of arsenic and other elements of interest is assessed using a continuous leaching method (involving the real-time measurement by ICP-MS of the fraction released by the different artificial digestive fluids). By coupling this leaching method with the above validated speciation analysis method, the bioaccessibility of different arsenic species is also assessed.

Made available in DSpace on 2016-04-28T20:39:34Z (GMT). No. of bitstreams: 1 Regina Orth de Aragao.pdf: 318061 bytes, checksum: 46eec2cc6b909761cac87053ca9af5ab (MD5) Previous issue date: 2007-10-17 / This research has taken the child s therapeutic work as a starting point, passing through the therapeutic processes carried out with pregnant women, to conceive the study of the psychic processes that take place before birth. The main question of this research can be presented this way: in what manner what is anticipated and built in the mother s psyche during pregnancy will strongly influence her relation with the baby, and consequently, will present a relevant effect upon the psychic constitution of this new being. This maternal psychic preparation involves at least three dimensions: the time, the space and the identification, all of them touched by changes in the narcissistic processes of the woman. The lasting of the pregnancy establishes a time that allows the pregnant woman to pass through the process of transformation in her psyche, together with the body changes and the growing of the baby in her womb. In another dimension, these same body changes produce clear alterations in the internal feeling of her own psychic space. This psychic space changes in order to receive and to contain another being inside her body and in her life. Those processes are related to the alterations in the maternal narcissism, establishing the possibilities of one including or excluding narcissism, as we have proposed to nominate these two alternatives of maternal narcissistic position in relation to the baby. And as one fundamental intra-psychic dynamics, we can find the developments of her edipian history; mainly, the specificities of the relation between the girl and the mother of the first years of life, that will be relevant to the construction of the maternal role. / Esta pesquisa tomou a clínica da criança como ponto de partida para, passando pela clínica da maternidade, se voltar para o estudo dos processos psíquicos que se dão no tempo antes do nascimento, e sua questão central pode ser assim apresentada: de que maneira aquilo que se antecipa e se constrói no psiquismo da mãe durante o tempo de espera da criança marcará sua relação com o filho, e, portanto influenciará a própria constituição do psiquismo desse novo ser? Essa preparação psíquica materna envolve pelo menos três dimensões: o tempo, o espaço, e a identificação, todas elas atravessadas por alterações na estruturação narcísica da mulher. A duração da gravidez estabelece uma temporalidade que permite à gestante percorrer os processos de transformação em seu psiquismo, em paralelo às mudanças corporais e ao crescimento do bebê em seu ventre. Em outra dimensão, essas mesmas mudanças corporais deslocam o sentimento de seu próprio espaço psíquico, que se altera para conter um outro ser dentro do corpo e dentro da vida. Trata-se de processos que envolvem alterações no narcisismo materno, estabelecendo as possibilidades de um narcisismo englobante ou excludente, como propusemos denominar essas duas alternativas da posição narcísica materna em relação ao bebê. E como dinâmica intrapsíquica fundamental encontram-se os desenvolvimentos da história edipiana; especialmente os percalços da relação da menina com a mãe dos primeiros tempos serão determinantes para a construção da função materna

Made available in DSpace on 2016-04-27T18:12:23Z (GMT). No. of bitstreams: 1 Iamara Jacintho de Azevedo Rios.pdf: 2132240 bytes, checksum: 32d35e47eb58ea5171401bb058d07b60 (MD5) Previous issue date: 2007-09-18 / This study examines the relationship between mothers and premature babies, during prolonged hospitalization in a neonatal intensive therapy unit (NITU). To consider the matter, an interview with the mother of an extreme premature baby was conducted. She recorded the hospitalization period using a scrapbook, i.e., a book through which hospitalization history is recorded in details, using customized pages and a wide variety of materials. The history of both mother and baby, here called Maria and Matheus, allowed us to explain the importance of the consideration by the speech pathologist/audiologist of such relationship in a hospital setting, having as main reference the aspects of the Winnicottian theory. The study approached particularly the concepts of primary mother concerns and holding, which are fundamental in the first moments of life, defined by the author as absolute dependency. Finally, the study concludes that, even in such an adverse situation as is baby's prolonged hospitalization, the mother is indeed able to develop her own mother style. Therefore, the entire team of professionals involved, including the speech pathologist/audiologist, is responsible for helping increase the offer of holding in an environment different from home; this certainly supports the development of healthy children, who are able to pass to the next stages of growth / O presente estudo trata da relação mãe e bebê prematuro, durante o período de internação prolongada em Unidade de Terapia Intensiva Neonatal (UTIN). Para refletir sobre essa questão, foi realizada uma entrevista com a mãe de um bebê prematuro extremo que fez um registro dos momentos de internação hospitalar, usando para isso um scrapbook - palavra inglesa que significa, literalmente, livro de retalhos e que registra uma história minuciosamente, em páginas personalizadas e com uma grande variedade de materiais. A história vivida por ambos, mãe e bebê, aqui denominados Maria e Mateus, nos permitiu elucidar a importância de o fonoaudiólogo contemplar esse vínculo no setting hospitalar, tendo como referência principal aspectos da teoria winnicottiana. Em especial, foram abordados os conceitos de preocupação materna primária e de holding, primordiais no momento inicial da vida, caracterizado pelo autor como de dependência absoluta. Por fim, foi possível concluir que, mesmo em uma situação tão adversa, como a internação hospitalar prolongada do bebê, a mãe pode sim desenvolver seu estilo de ser mãe, sendo que cabe a toda equipe de profissionais envolvidos, incluindo o fonoaudiólogo, facilitar a oferta de holding em um ambiente que é tão diferente da casa, o que certamente favorece o desenvolvimento de crianças saudáveis, em condições de atravessarem as próximas etapas de amadurecimento

Thesis (M.Sc. (Chemistry)) --University of Limpopo, 2017 / The presence of polycyclic aromatic hydrocarbons (PAHs) in the environment is of major concern since these compounds are highly persistent, toxic and wide spread pollutants. The aim of this study was to evaluate the levels of PAHs in water and sediment samples collected from Blood and Mokolo Rivers in Limpopo Province, South Africa. Liquid-liquid extraction (LLE) was used for the extraction of PAHs from water, whereas PAHs in sediments were extracted using optimised microwaveassisted extraction (MAE). Furthermore, ultrasonication and a combination of ultrasonication and mechanical agitation were used for the extraction of PAHs from sediments samples. The quantification of sixteen (16) PAHs in water and sediment was carried out using gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode and by GC-flame ionisation detector (GC-FID). Concentrations of PAHs in sediments were higher than in water. The highest concentrations of PAHs were obtained in Mokolo River sediments, with the concentration ranging between 0.044 and 51.9 mg/kg. The levels of PAHs recorded in Blood River sediments were lower than those obtained in Mokolo River with concentrations ranging between 0.014 and 3.10 mg/kg. In water samples, higher levels of PAHs were observed in Mokolo River (between 0.0219 and 1.53 µg/L) while lower concentrations were recorded in Blood River (between 0.0121 and 0.433 µg/L). In water and sediment samples from both Rivers, higher molecular weight (HMW) PAH compounds (4-6 rings) were found at greater concentration levels than lower molecular weight (LMW) PAHs (2-3 rings), and this can be attributed to pyrogenic activities in the study areas. The efficiencies and accuracy of the methods for the extraction of PAHs were determined by assessing the recoveries of samples spiked with known amount of standards (for water samples), while a certified reference material (CRM) was used for sediments. Percentage recoveries ranged from 67.6 to 115% for LLE and 83.8 to 125% for MAE for both sample types. Diagnostic ratio was used for the source identification of PAHs in sediment samples. Several PAHs ratios indicated that both pyrogenic and petrogenic could be the sources of these compounds in both rivers. Toxic equivalency factors (TEFs) and benzo(a)pyrene equivalent (BaPE) were used to quantitatively estimate the PAHs potential human health risk. The assessment of ecotoxicological risk indicated that the v sediment samples collected from Mokolo River are at high toxicity risk while sediments from Blood River are at low sediment toxicity risk. / Water Research Commission (WRC), National Research Foundation (NRF) and Sasol Inzalo Foundation

Different methods for quality assessment of separated andcommingled plastics from household and electronic waste havebeen developed. Especial attention has been given tospectroscopic methods since they are non-destructive andrequire little or no sample preparation at all. A wide variety of low molecular weight compounds have beenidentified in recycled polyethylene (HDPE) and polypropylenefrom hard packaging waste by gas chromatography- massspectroscopy (GC-MS) after microwave assisted extraction (MAE).Low molecular weight substances such as alcohols, esters,ketones and fragrance and flavour compounds were detected inthe recycled resins. The major category of compounds identifiedin the virgin resins is conformed by aliphatic hydrocarbonssuch as alkanes and alkenes. It was found that theconcentration of aromatic hydrocarbons without functionalgroups, e.g. ethylbenzene and xylenes in recycled HDPE wasapprox. 5 times higher and equal to 120 and 35 ppb,respectively. The potential of near infrared (NIR) and Fourier transformRaman (FT-Raman) spectroscopy in combination with multivariateanalysis as a rapid, non-destructive and accurate analyticalmethod has been studied and the feasibility of these methodsfor at/in line characterisation of several properties ofrecyclates has also been explored. NIR in diffuse reflectance mode has been successfully usedfor quantification of antioxidants in polyethylene, thestandard error of prediction is almost comparable to the errorof wet methods, i.e., extraction plus liquid chromatography.The error of prediction of this method is 35 ppm for Irganox1010 and 68 ppm for Irgafos 168. The inaccuracy in thequantification of Irgafos 168 is due to the fact that thisantioxidant degrades during polymer processing. NIR and Mid-infrared (Mid-IR) worked well for fastdetermination of molecular weight and crystallinity of therecycled HDPE and acceptable errors of prediction, comparableto that of the reference methods, i.e. size exclusionchromatography (SEC) and differential scanning calorimetry(DSC) have been obtained. The present thesis also shows that NIR and Raman are goodcandidates for in/on line compositional analysis of mixedpolymer fractions from recycled plastic waste. Diffusereflectance NIR allows a rapid and reliable measurement ofpellets and requires no previous sample preparation. Thecomposition of binary blends can be determined with highaccuracy. The PP content in the PP/HDPE blends was predictedwith a RMSEP equal to 0.46 %w in the 0-15 %wt region and theRMSEP for PP in the PP/ABS blends was 0.3 %wt. The thermal and thermoxidative stability of recycled PP,HDPE and a 20/80 PP/HDPE blend subjected to multiple extrusionhave been studied by DSC, thermal analysis (TGA) andchemiluminiscence (CL). A decrease in Toxand OIT was observed after each extrusion step.The drop in OIT was sharper after the first two extrusions. TheOIT values produced by DSC and CL were in good agreement.However, CL provided more information about the oxidationprocess taking place in the blends. The moisture content in recycled polyamide 6,6 was readilydetermined by NIR in transmission mode and it could bepredicted with a RMSEP = 0.05 %wt. The accuracy of the methodappeared to be as good as that of the more time consumingthermal methods such as TGA, DSC and loss on dry (LOD), whichwere used as reference methods. The influence of differentamounts of water on the viscoelastic properties of nylon hasbeen investigated. <b>Keywords:</b>Recycling, HDPE, PP, blends, nylon 6,6, ABS,water content, MAE, GC-MS, NIR, FT-Raman, chemiluminiscence,low molecular weight compounds, antioxidant content,crystallinity, molecular weight, thermal stability,characterisation methods, analysis of polymers, blends.

<p>Different methods for quality assessment of separated andcommingled plastics from household and electronic waste havebeen developed. Especial attention has been given tospectroscopic methods since they are non-destructive andrequire little or no sample preparation at all.</p><p>A wide variety of low molecular weight compounds have beenidentified in recycled polyethylene (HDPE) and polypropylenefrom hard packaging waste by gas chromatography- massspectroscopy (GC-MS) after microwave assisted extraction (MAE).Low molecular weight substances such as alcohols, esters,ketones and fragrance and flavour compounds were detected inthe recycled resins. The major category of compounds identifiedin the virgin resins is conformed by aliphatic hydrocarbonssuch as alkanes and alkenes. It was found that theconcentration of aromatic hydrocarbons without functionalgroups, e.g. ethylbenzene and xylenes in recycled HDPE wasapprox. 5 times higher and equal to 120 and 35 ppb,respectively.</p><p>The potential of near infrared (NIR) and Fourier transformRaman (FT-Raman) spectroscopy in combination with multivariateanalysis as a rapid, non-destructive and accurate analyticalmethod has been studied and the feasibility of these methodsfor at/in line characterisation of several properties ofrecyclates has also been explored.</p><p>NIR in diffuse reflectance mode has been successfully usedfor quantification of antioxidants in polyethylene, thestandard error of prediction is almost comparable to the errorof wet methods, i.e., extraction plus liquid chromatography.The error of prediction of this method is 35 ppm for Irganox1010 and 68 ppm for Irgafos 168. The inaccuracy in thequantification of Irgafos 168 is due to the fact that thisantioxidant degrades during polymer processing.</p><p>NIR and Mid-infrared (Mid-IR) worked well for fastdetermination of molecular weight and crystallinity of therecycled HDPE and acceptable errors of prediction, comparableto that of the reference methods, i.e. size exclusionchromatography (SEC) and differential scanning calorimetry(DSC) have been obtained.</p><p>The present thesis also shows that NIR and Raman are goodcandidates for in/on line compositional analysis of mixedpolymer fractions from recycled plastic waste. Diffusereflectance NIR allows a rapid and reliable measurement ofpellets and requires no previous sample preparation. Thecomposition of binary blends can be determined with highaccuracy. The PP content in the PP/HDPE blends was predictedwith a RMSEP equal to 0.46 %w in the 0-15 %wt region and theRMSEP for PP in the PP/ABS blends was 0.3 %wt.</p><p>The thermal and thermoxidative stability of recycled PP,HDPE and a 20/80 PP/HDPE blend subjected to multiple extrusionhave been studied by DSC, thermal analysis (TGA) andchemiluminiscence (CL). A decrease in T_oxand OIT was observed after each extrusion step.The drop in OIT was sharper after the first two extrusions. TheOIT values produced by DSC and CL were in good agreement.However, CL provided more information about the oxidationprocess taking place in the blends.</p><p>The moisture content in recycled polyamide 6,6 was readilydetermined by NIR in transmission mode and it could bepredicted with a RMSEP = 0.05 %wt. The accuracy of the methodappeared to be as good as that of the more time consumingthermal methods such as TGA, DSC and loss on dry (LOD), whichwere used as reference methods. The influence of differentamounts of water on the viscoelastic properties of nylon hasbeen investigated.</p><p><b>Keywords:</b>Recycling, HDPE, PP, blends, nylon 6,6, ABS,water content, MAE, GC-MS, NIR, FT-Raman, chemiluminiscence,low molecular weight compounds, antioxidant content,crystallinity, molecular weight, thermal stability,characterisation methods, analysis of polymers, blends.</p>

Previous research has shown that African American children are prone to score lower on vocabulary tests when compared to their white peers (Champion et al., 2003; Qi et al., 2006; Restrepo et al., 2006; Thomas-Tate et al., 2006; Washington & Craig, 1992). The dialect spoken by these children may be affecting their performance. However, little is known about how dialect use interacts with word learning abilities. The current study continues a project initiated by Wyatt, Bahr, and Silliman (2007) which examined dialectal influences on the fast mapping of novel stimuli in preschool children. The participants in the current study were 19 typically developing school-age children, who were recruited from a local elementary school in West Central Florida. Prior to the experiment, the children completed a dialectal variation assessment (DELV) and a receptive vocabulary assessment (PPVT-4). The fast mapping task utilized a modified version of the blank-comparison technique (Costa, Wilkinson, McIlvane, & de Souza, 2001). For this task, twelve non-words were developed to include three AAE phonetic features: final consonant cluster reduction, backing in /str/ clusters, and final consonant devoicing. The non-words were presented in five tasks (training, recognition, comprehension, dialect, and production). Participant responses were analyzed qualitatively and described by dialect group and AAE feature. It was anticipated that fast mapping would be influenced by dialect use; however, this was not the case. Dialect played a small role in the comprehension task -- children who spoke AAE experienced more difficulty with /skr/ non-words. Otherwise, results indicated that responses, especially during the dialect and productions tasks, were similar with numerous errors noted in both dialect groups. A notable difference was in the production of final consonant clusters, where children who spoke AAE evidenced a slight advantage. The lack of a dialect group effect was not surprising since these tasks required the participant to respond to subtle phonetic differences in the target stimuli. As a whole, dialectal influences seemed to be task and feature related. These results will be compared to the previous investigation with preschoolers (Wyatt et al., 2007) and implications for future research will be presented.