• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 119
  • 59
  • 27
  • 18
  • 17
  • 11
  • 7
  • 4
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 330
  • 98
  • 42
  • 32
  • 31
  • 28
  • 26
  • 26
  • 22
  • 21
  • 20
  • 20
  • 20
  • 19
  • 19
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

Validación de la prueba de alfabetización inicial (PAI) en instituciones educativas públicas y privadas pertenencientes a la UGEL No 07.

Bonilla Caviedes, Fiorella Nieves, Botteri Gálvez, Andrea, Vílchez Charún, Adriana Victoria 05 December 2013 (has links)
This descriptive research with a descriptive design, drawn from a cluster sampling, consisting of 200 5-year-old children from public and private schools belonging to the UGEL No. 07. The Test of Early Literacy Learning – PAI by Malva Villalón and Andrea Rolla which assesses phonological awareness, print awareness, alphabet knowledge, reading and writing, was applied. Within the main results, a reliability coefficient of 0.96 in the overall score was found and intercorrelation coefficients of the other sub tests reached statistically significant values. Additionally, there was a good internal consistency reliability and solid validity indicators to assess harmoniously the 5 key components. Apercentile rank was also carried out for the target population. Key words: Validation, Early literacy, phonological awareness, learning, reading, writing. / Esta investigación de tipo descriptivo, diseño descriptivo simple contó con una muestra realizada mediante un muestreo por conglomerados, conformada por 200 niños y niñas de 5 años procedentes de Instituciones Educativas Públicas y Privadas pertenecientes a la UGEL Nº 07. El instrumento utilizado fue la Prueba de Alfabetización Inicial - PAI, de Malva Villalón y Andrea Rolla, que evalúa conciencia fonológica, conciencia de lo impreso, conocimiento del alfabeto, lectura y escritura. Dentro de resultados más relevantes, se halló un coeficiente de fiabilidad del puntaje global de 0.96 y los coeficientes de intercorrelación de los sub test alcanzaron valores estadísticamente muy significativos. Asimismo, se halló una buena confiabilidad de consistencia interna y sólidos indicadores de validez para evaluar de manera armoniosa los cinco componentes fundamentales. Además se realizó un baremo en percentiles para la población elegida.
162

Laser-Induced Breakdown Spectroscopy: Simultaneous Multi-Elemental Analysis and Geological Applications

Sanghapi, Herve Keng-ne 06 May 2017 (has links)
Under high irradiation, a fourth state of matter named plasma can be obtained. Plasmas emit electromagnetic radiation that can be recorded in the form of spectra for spectroscopic elemental analysis. With the advent of lasers in the 1960s, spectroscopists realized that lasers could be used simultaneously as a source of energy and excitation to create plasmas. The use of a laser to ignite a plasma subsequently led to laser-induced breakdown spectroscopy (LIBS), an optical emission spectroscopy capable of analyzing samples in various states (solids, liquids, gases) with minimal sample preparation, rapid feedback, and endowed with in situ capability. In this dissertation, studies of LIBS for multi-elemental analysis and geological applications are reported. LIBS was applied to cosmetic powders for elemental analysis, screening and classification based on the raw material used. Principal component analysis (PCA) and internal standardization were used. The intensity ratios of Mg/Si and Fe/Si observed in talcum powder show that these two ratios could be used as indicators of the potential presence of asbestos. The feasibility of LIBS for the analysis of gasification slags was investigated and results compared with those of inductively-coupled plasma−optical emission spectrometry (ICP-OES). The limits of detection for Al, Ca, Fe, Si and V were determined. The matrix effect was studied using an internal standard and PLS-R. Apart from V, prediction results were closed to those of ICP-OES with accuracy within 10%. Elemental characterization of outcrop geological samples from the Marcellus Shale Formation was also carried out. The matrix effect was substantially reduced. The limits of detection obtained for Si, Al, Ti, Mg, Ca and C were determined. The relative errors of LIBS measurements are in the range of 1.7 to 12.6%. Gate delay and laser pulse energy, have been investigated in view of quantitative analysis of variation of trace elements in a high-pressure environment. Optimization of these parameters permits obtaining underwater plasma emission of calcium with quantitative results on the order of 30 ppm within a certain limit of increased pressure. Monitoring the variation of the trace elements can predict changes in the chemical composition in carbon sequestration reservoir.
163

The effect of low marine ingredient feeds on the growth performance, body composition and health status of Atlantic salmon (Salmo salar)

Metochis, Christoforos P. January 2014 (has links)
Fish meals (FM) and fish oils (FO) are used extensively as the main protein and lipid sources respectively in industrially compounded salmon feeds, mainly due to their excellent nutritional properties. Nevertheless, several reasons dictate the utilisation of sustainable alternative protein and lipid sources and the subsequent reduction in the reliance on fishery-products in aquafeeds. Soy protein concentrate (SPC) is a very promising alternative to FM Hence, the main objective of the present thesis was to investigate the effects of the increased substitution of FM withSPC, lysine and methionine on the growth performance and immune responses of early and late stage Atlantic salmon parr prior to and after vaccination with commercial vaccines (Experiments II and V presented in Chapters 4 and 6). Furthermore the effects of increasing dietary levels of SPC with consistent and/or increasing dietary supplementation of phosphorus on the Atlantic salmon parr’ body proximate and mineral composition or the skeletal mineral composition respectively, prior and post-vaccination with commercial vaccines; under continuous light or under 12 hours light: 12 hours dark photoperiod (Experiments I and V presented in Chapters 3 and 5 respectively). Lastly the impact of FM-, FO- and fishery-free diets on the growth, carcass proximate composition and immune status of Atlantic salmon post-smolts was investigated (Experiment III presented in Chapter 7). In the latter experiment six diets were tested including: two commercially applied marine based diets, one with partial inclusion of vegetable proteins (VPs) and oils (VOs) according to the EU standards (2011-12) (MBE) and one with partial inclusion of VPs, VOs and land animal-by product (ABP) proteins according to the non-EU standards (MBABP); a fully vegetable protein (VP) diet; a fully algal and vegetable oil (VO) diet; a marine-free VP and VO and algal oil diet (VP/VO) diet; and a marine-free diet with a mix of VPs and land ABP proteins and lipid from VOs and algal oils (MFABP). The results of the Experiments I and II (Chapters 3 and 4) show that late Atlantic salmon parr can grow efficiently on SPC80 diets, however, they require longer periods to adapt to these diets compared to fish fed diets containing lower levels of SPC as a protein source. Decreased mineralisation of body cross-section was observed for salmon fed increasing dietary SPC. Vaccination improved mineralisation for the high dietary SPC salmon groups. However, continuous light exposure promoting fast growth appeared to be detrimental for Atlantic salmon body cross ash, Ca, Mg, Mn, P and Zn. Moreover, it was demonstrated that substitution of up to 50% of high quality FM protein with SPC and constantly added P has the minimum possible impact on late salmon parr growth, whereas it stimulates several immune parameters prior to immunisation. Immunostimulatory effects were also shown for the diets with higher dietary SPC levels. It is not clear if these results were an effect of increased FM replacement with SPC or not properly balanced levels of dietary P. The Experiments III and IV (Chapters 5 and 6) illustrated that early stage Atlantic salmon parr can accept diets with up to 58% protein from SPC without serious effects on body growth. However, higher levels can severely affect salmon growth performance. Moreover, it was shown that long-term feeding of salmon with increasing dietary SPC combined with increasing phosphate supplementation, alone or in combination with vaccination can actually be beneficial for Atlantic salmon parr bone mineralisation. However, mineralisation in vaccinated fish was higher than in PBS-injected fish. This could be linked to the slower growth of vaccinated salmon allowing their developing bones to mineralise properly. Changes in the modulation of the different components of the complement activity was revealed in Atlantic salmon fed increasing dietary levels of SPC. The modulation of complement activity was demonstrated at both studies utilising increasing dietary SPC concentrations, indicating that complement componenets are among the most prominent immunological markers upon dietary FM replacement with SPC. However, overall no differences in total complement activity and therefore the immune capacity and resistance against Aeromonas salmonicida were observed among the salmon groups receiving increasing levels of SPC. Lastly in Experiment V (Chapter 7) higher growth performance indices (weight gain, SGR and TGC) were evident in the MBE salmon compared to the MBABP group, salmon fed diets with complete eleimintion of FM or FO (VP and VO respectively) and fish fed two diets with total substitution of both marine derived feed ingredients, three months after the start of the feeding trial. Higher feed intake was demonstrated for both MBE and VP salmon compared to the other groups for the duration of the first period. The above results could have been influenced by discrepancies in the size of the fish at the start ofthe trial, revealing flaws in the experimental design. Both MBE and VP salmon groups also presented the highest feed conversion ratios, revealing the lowest efficiency in dietary nutrient utilisation in comparison to the rest of salmon which exhibited no differences in feed efficiency, revealing an overall better performance of the MBABP and diets with low levels of marine feedstuffs. Improved FI compared to the values of the first period and higher SGR and TGC values were demonstrated for salmon from the latter treatments compared to MBE and VP salmon, during the second part of the study, revealing compensatory growth for these groups. VP salmon demonstrated the highest and VO salmon the lowest condition factor values. The former finding might possibly be related with higher fat accumulation in the viscero-hepatic tissues. No differences were observed in carcass moisture, protein, fat and ash concentrations among the dietary groups of fish. Furthermore, no differences were demonstrated in terms of total and differential leucocyte counts, plasma haemolytic activity, plasma protein and total IgM levels, stimulated and non-stimulated HKM burst activity among the different dietary groups. However, lower haematocrit values were observed in the MB and VO-fed groups compared to the MFABP and VP/VO groups. Furthermore, decreased lysozyme activity was observed for all diets in contrast to the control groups, whereas FM-free diets promoted plasma anti-protease activity. The former result could have been an effect of either immune or stress induction, whereas the second is regarded as an immunostimulatory effect. The results suggest that marine-oil, marine-protein and marine-free diets could be satisfactorily used for Atlantic salmon post-smolts without severe reductions in their innate immune responses, although longer adaptation periods might be required for the fish to fully accept these diets.
164

Avaliação de métodos empregando a espectrometria de massas com plasma acoplado (ICP-MS) para determinação de impurezas elementares e especiação química de arsênio e mercúrio em fármacos e excipientes / Evaluation of methods using coupled plasma mass spectrometry (ICP-MS) for determination of elemental impurities and chemical speciation of arsenic and mercury in drugs and excipients

Aguiar, Giovanna de Fatima Moreno 13 September 2017 (has links)
Com o aumento das exigências regulatórias e estabelecimento de limites mais restritos para impurezas elementares em fármacos e excipientes usados em formulações farmacêuticas, ocorreu uma busca por técnicas analíticas capazes de quantificar elementos em níveis traço e assegurar a qualidade e a segurança dos medicamentos. A espectrometria de massas com plasma acoplado indutivamente (ICP-MS) é uma técnica multielementar, que apresenta alta sensibilidade e é empregada com eficiência na análise de elementos traço em diferentes matrizes. O ICP-MS, acoplado a um sistema separador como o cromatógrafo líquido de alta eficiência (HPLC), possibilita a especiação de elementos químicos, o que é importante, pois a toxicidade pode estar diretamente ligada à forma química do elemento, como ocorre para o Hg e As. Neste sentido, os objetivos deste trabalho foram desenvolver e validar um método de análise simples, rápido e com alta sensibilidade, para determinação de 15 impurezas elementares: As, Cd, Cr, Cu, Ni, Pb, V, Ir, Pd, Pt, Rh, Ru, Hg, Os e Mo, em diferentes fármacos e excipientes, em níveis que atendam aos novos critérios estabelecidos pelos órgãos regulatórios, avaliar a utilização da cela de reação dinâmica (DRC) para eliminação de interferências espectrais na determinação de As, Cr e V, realizar a especiação de As e Hg, e aplicar esta metodologia para análise de diversas amostras comprovando sua robustez, versatilidade e vantagens para utilização em rotina. Foram avaliadas cinco estratégias de preparo de amostra: digestão em micro-ondas sistema fechado e digestão em micro-ondas - sistema aberto, digestão em banho-maria, diluição direta em meio ácido e extração utilizando ponteira de ultrassom. Através de ensaios de recuperação e materiais de referência certificados, os melhores resultados (84 a 101%) foram obtidos com a digestão das amostras em sistema fechado de micro-ondas e extração por ponteira de ultrassom. Os limites de detecção variaram entre 0,001 ng g-1 (103Rh) e 0,083 ng g-1 (75As). Em seguida, a metodologia analítica foi empregada para determinação dos elementos em estudo em 74 amostras de fármacos e excipientes. O elemento mais frequentemente encontrado foi o Cu, seguido por Cr, Mo, Ni, Pd e V. Já os elementos químicos Ir, Pt, Os e Ru não foram detectados. Cabe destacar que as concentrações de Pd, Rh, As, Cd, Cr, Cu, Ni, V e Mo encontraram-se acima do limite preconizado pela farmacopeia americana em algumas amostras. A análise por especiação química de As mostrou que as amostras possuíam apenas as formas inorgânicas e mais tóxicas. Em relação ao Hg, apenas uma amostra apresentou níveis detectáveis deste elemento, mas a concentração estava abaixo do limite estabelecido pela farmacopeia americana. / Due to quality and safety reasons, regulatory requirements and establishment of more restricted limits for elemental impurities in drugs and excipients are increasing. These regulations promoted a search for simple and robust analytical techniques for quantification of trace elements. Inductively coupled plasma mass spectrometry (ICP-MS) is an attractive technique for this purpose, presenting multielement and high sensitivity capabilities. ICP-MS can be hyphenated to separation techniques such as high-performance liquid chromatography (HPLC), enabling chemical speciation analysis. Speciation analysis may reveal the chemical form of the element that may be more directly related to the toxicity. In this sense, the objectives of this work were to develop and validate a simple, fast and highly sensitive method for the determination of 15 elemental impurities: As, Cd, Cr, Cu, Ni, Pb, V, Ir, Pd, Rh, Ru, Hg, Os and Mo, in different drugs and excipients, at levels that meet the new criteria established by the regulatory agencies. We also evaluated the use of the dynamic reaction cell (DRC) to eliminate spectral interferences for As, Cr And V. Finally, for As and Hg, speciation methods were applied. All analysis were performed focusing on robustness, versatility and sample high-throughput. We tested five sample preparation strategies: closed microwave system digestion, microwave digestion - open system, water bath digestion, direct acid dilution and ultrasound probe extraction. Recovery studies in ordinary samples and reference certified materials were observed with the closed microwave digestion system and ultrasound probe extraction (84 and 101%). Detection limits ranged from 0.001 ng g-1 for 103Rh to 0.083 ng g-1 for 75As. The analytical methodology was then applied for the determination of the elements in study in 74 samples of drugs and excipients. The most frequently found element was Cu, followed by Cr, Mo, Ni, Pd and V. The chemical elements Ir, Pt, Os and Ru were not detected. It should be mention that the concentrations of Pd, Rh, As, Cd, Cr, Cu, Ni, V and Mo were above the limit recommended by the American pharmacopeia in some samples. Only inorganic arsenic (most toxic forms) was found in samples by applying speciation analysis. Regarding Hg, only one sample had detectable levels of this element, but the concentration was below the limit established by the American pharmacopeia
165

Caracterização do material particulado em Cubatão / CHARACTERIZATION OF PARTICULATE MATTER IN CUBATÃO

Valarini, Simone Fernandes 05 May 2011 (has links)
Neste trabalho foi feita uma caracterização do material particulado coletado no Centro de Capacitação e Pesquisa em Meio Ambiente (CEPEMA) localizado na cidade de Cubatão, na Baixada Santista. As coletas ocorreram entre março de 2009 e novembro de 2010, utilizando amostradores de material particulado fino, grosso e inalável (Mini-Vol) e um impactador em cascata (MOUDI) para as várias frações do material particulado, durante oito campanhas experimentais. Foi realizada uma caracterização climatológica com os dados de temperatura, pressão atmosférica, umidade relativa, velocidade e direção do vento das estações da CETESB em Cubatão: Centro (10 anos), Vila Parisi (10 anos) e Vale do Mogi (4 anos). Os dados de chuva foram obtidos da Defesa Civil para a cidade de Santos. A maior parte das coletas de 2009 ocorreu em períodos em que houve precipitação, ao passo que as coletas de 2010 foram amostradas em períodos mais secos. O material particulado fino (MPF) teve concentrações médias de: 15,7 e 18,8 g m-3 em 2009 e 2010, respectivamente, quando coletado pelo MOUDI; e 15,8 e 23,6 g m-3, quando coletado pelo Mini-Vol. O material particulado grosso (MPG) teve concentrações médias de: 11,4 e 14,1 g m-3 em 2009 e 2010, respectivamente, quando coletado pelo MOUDI; e 18,9 e 13,4 g m-3, quando coletado pelo Mini-Vol. As análises de refletância mostraram que o Black Carbon está quase totalmente no MPF, chegando a 15% (20%) da massa do MPF quando coletado pelo MOUDI (Mini-Vol). Os íons dominantes são sulfato (SO42), nitrato (NO3), sódio (Na+), amônio (NH4+) e cálcio (Ca2+) e os elementos dominantes são enxofre (S), silício (Si) e ferro (Fe). As distribuições de tamanho mostram uma moda de nucleação bastante pronunciada para o S, K, Cl e P, indicando a contribuição de fontes antropogênicas e formação secundária do aerossol. As maiores concentrações de Si, Cl, Ca, Fe, Ca2+, NO3 e Na+ se encontram no MPG. Para o Cl e Na+, foram encontradas maiores concentrações nas amostras diurnas com vento do quadrante sul-sudoeste na estação do Centro, demonstrando a contribuição marinha. / This work evaluated the particulate matter (PM) collected at the Environmental Research and Training Center (CEPEMA) located in Cubatão City. Sampling was made between 2009, March and 2010, November for fine, coarse and inhalable aerosol (Mini-Vol) and for the various fractions of PM with a cascade impactor (MOUDI) during eight experimental campaigns. A climatological study was performed for temperature, pressure, relative humidity, wind speed and direction using data from CETESB stations: Centro (10 years), Vila Parisi (10 years) and Vale do Mogi (4 years). Precipitation data was obtained from the Civil Defense for the city of Santos. Most samplings made during 2009 were concomitant with rainy days, whereas 2010 samplings were made in drier periods. Fine particulate matter (FPM) had average concentrations of: 15.7 and 18.8 g m-3 in 2009 and 2010, respectively, with MOUDI and 15.8 and 23.6 g m-3, with Mini-Vol. Coarse Particulate Matter (CPM) had average concentrations of: 11.4 and 14.1 g m-3 in 2009 and 2010, respectively, with MOUDI, and 18.9 and 13.4 g m-3, with Mini-Vol. Reflectance analysis showed that the Black Carbon is almost completely in the FPM, reaching up to 15 % (20 %) of the FPM mass when sampled with MOUDI (Mini-Vol). Dominant ions are sulfate (SO42-), nitrate (NO3-), sodium (Na+), ammonium (NH4+) and calcium (Ca2+) and the dominant elements are sulfur (S), silicon (Si) and iron (Fe). The size distributions shows a very pronounced nucleation mode for the S, K, P and Cl, indicating the contribution of anthropogenic sources and secondary aerosol formation. The highest concentrations of Si, Cl, Ca, Fe, Ca2+, NO3- and Na+ are in CPM. For Cl- and Na+, major concentrations were found in samples with diurnal south-southwest wind indicating marine aerosol contribution.
166

ASSOCIATED PARTICLE NEUTRON ELEMENTAL IMAGING FOR NONINVASIVE MEDICAL DIAGNOSTICS

Michael R Abel (6594194) 10 June 2019 (has links)
<p>A novel system has been simulated with accompanying experimental data that is designed to provide spatial information of elemental concentrations at biologically relevant levels. Using a deuterium-deuterium (DD) neutron generator, two large high-purity germanium (HPGe) detectors operating in tandem, and the associated particle imaging (API) technique, elemental iron concentrations as low as 100 ppm have been resolved <i>in vivo</i> in the liver of a simulated reference man with an equivalent dose to the region of interest of < 5 mSv and an estimated whole body dose of 0.82 mSv. Using the Monte Carlo Neutral Particle (MCNP) transport code, achievable spatial resolutions in the projective and depth dimensions of < 1 cm and < 3 cm are achievable, respectively, for iron-containing voxels on the order of 1,000 ppm Fe – with an overall 225 ps system timing resolution, 6.25 mm<sup>2</sup> imaging plate pixels, and a Gaussian-distributed DD neutron source spot with a diameter of 2 mm. Additionally, as a departure from Monte Carlo simulations, the underlying concepts of fast neutron inelastic scatter analysis as an initial surrogate to true associated particle neutron elemental imaging (APNEI) were demonstrated using a DD neutron generator, iron-made interrogation targets, a sodium iodide detector, and physical neutron/gamma shielding, which yielded an approximate detection limit for iron of 3.45 kg which was simulated to improve to 0.44 kg upon incorporation of the associated particle collimation methodology.</p> The API technique allows concentrations of elements such as iron to be quantified due to time-tagged electronic collimation and corresponding background signal reduction. Inherent to the API process is the collection of spatial and temporal information, which allows the perceived origin of a photon signal to be identified in 3D space. This process was modeled algorithmically in MCNP and employed using relevant equipment and shielding geometries. By leveraging the capabilities of modern-day neutron generator and coincident timing technologies with high throughput signal processing discrimination, the applicability of APNEI to disease diagnostics and etiological research is promising.
167

Caracterização química elementar e proteica da polpa de graviola / Elemental and protein determinations in graviola pulp

Kelmer, Gislayne Aparecida Rodrigues 27 April 2012 (has links)
No presente trabalho foram desenvolvidos métodos para a determinação de Al, B, Ba, Ca, Co, Cu, Cr, Fe, K, Li, Mg, Mn, P, S, Si, Sn, Sr, Ti, V e Zn por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) e As, Cd, Pb e Se por espectrometria de absorção atômica com forno de grafite e detecção simultânea (SIMAAS) em polpa de graviola (Annona muticata L.). A determinação de proteínas bem como a estimativa da presença de Fe, Cu, Mn e Zn a elas associados também foram investigados. Para as determinações elementares foi utilizada polpa de graviola, seca em estufa a 50° C, digeridas com mistura oxidante diluída (2 mL HNO3 + 1 mL H2O2 + 3 mL H2O) e aquecimento em forno de micro-ondas com frasco fechado. A avaliação da exatidão dos métodos foi feita a partir da análise de material de referência certificado (Citrus Leaves SRM 1572, NIST) e os resultados concordaram, para maioria dos elementos, em 95% como intervalo de confiança, quando aplicado o teste t-Student. A polpa também foi submetida a diferentes pré-tratamentos: 1) secagem por liofilização e moagem em moinho criogênico; 2) homogeneização da polpa in natura em moinho de facas; e 3) secagem em estufa a 50 °C e moagem em almofariz e pistilo. Nessa etapa, o objetivo foi avaliar a influência dos procedimentos de pré-tratamento nas extrações de proteínas. Massas de amostra (~5 g), após extração lipídica, foram submetidas à agitação (1 h) com 0,5 mol L-1 NaOH, tampão Tris-HCl (pH 7,5), 0,5 mol L-1 HCl e tampão CO32-/HCO31- (pH 10) para extração de proteínas. Os extratos foram analisadas por ICP OES para determinação de Cu, Fe, Mn e Zn e proteínas pelo método de Bradford. Alíquotas dos extratos foram submetidas à etapa de limpeza (clean up) utilizando acetona em banho de gelo, 0,5 mol L-1 HCl e 20% m v-1 de TCA para precipitação de proteínas. Somente acetona em banho de gelo foi eficiente na precipitação das proteínas. Os precipitados foram redissolvidos em tampão Tris-HCl e submetidos a separação por cromatografia de exclusão por tamanho e detecção por espectrofotometria UV (SEC-UV), a 280 nm. As proteínas totais nas amostras foram estimadas por análise elementar (CHN) e, em solução, pelo método de Bradford. Independente da solução extratora utilizada, o processo de liofilização e moagem criogênica foi o que proporcionou maior quantidade de proteínas extraídas. Porém, após a precipitação com 80 % v v-1 de acetona, maior quantidade de proteínas foram precipitadas da amostra in natura, indicando possíveis alterações durante a liofilização e secagem. Em todos os extratos submetidos a análises por SEC-UV foi observado maior quantidade de compostos de baixo peso molecular (< 6,5 kDa). Melhor eficiência de extração de proteínas e dos elementos Cu, Fe, Mn e Zn foi observada na extração com NaOH. Maiores concentrações dos elementos extraídos foram encontradas nas amostras in natura e menores nas amostras secas em estufa com moagem em almofariz e pistilo. / In this work methods for the determination of Al, B, Ba, Ca, Co, Cu, Cr, Fe, K, Li, Mg, Mn, P, S, Si, Sn, Sr, Ti, V and Zn by inductively coupled plasma optical emission spectrometry (ICP OES) and As, Cd, Pb e Se by simultaneous graphite furnace atomic absorption spectrometry (SIMAAS) in graviola pulp (Annona Muricata L.) were developed. The determination of proteins and the possible presence of Fe, Cu, Mn and Zn associated to them were also investigated. For elements determination, graviola pulp was dry in wood stove at 50%C and digested using diluted oxidant mixture (2 mL HNO3 + 1 mL H2O2 + 3 mL H2O) in closed-vessel microwave oven. The accuracy and precision of the methods were done by certified reference material analysis (Citrus Leaves SRM 1572, NIST), and the obtained results were in accordance at 95%, according Student-t test. The graviola pulp was also submitted to different pretreatments: 1) lyophilization and cryogenic grinding; 2) homogenization of the in natura sample in a knife mill; and 3) drying in wood stove at 50%C and grinding in a mortar. The objective of this step was to evaluate the influence of sample pretreatment on the protein extractions. After lipid extraction, sample masses (~5 g) were shacked (1 h) with 0.5 mol L-1 NaOH, Tris-HCl buffer (pH 7.5), 0.5 mol L-1 HCl and CO32-/HCO31- buffer (pH 10) for protein extraction. The extractants solutions were analyzed for Cu, Fe, Mn and Zn determinations by ICP OES and for protein determinations by Bradford method. A clean up step, using acetone in ice-bath, 0.5 mol L-1 of HCl and 20% m v-1 of TCA was used for protein precipitation. In this way, only acetone in ice-bath was efficient for precipitation. After that, precipitates were dissolved in Tris-HCl buffer and analyzed by size exclusion chromatography with UV detection (SEC-UV), at 280 nm. Total protein contents in the sample and in the extracting solutions were determined by elemental analysis (CHN) and Bradford method, respectively. For all extracting solutions, the lyophylization and cryogenic grinding procedure showed the best efficiency for proteins extraction. However, after precipitation with acetone 80 v v-1, higher amount of proteins were observed for in natura sample, indicating some structure protein modification during the lyophylization or drying pretreatment steps. In general, low molecular weight compounds (< 6,5 kDa) were observed for all extracting solutions. The NaOH extractor showed much better efficiency for proteins and Cu, Fe, Mn and Zn extraction. Higher concentration of the extracting elements were found for in natura samples and lower for drying in wood stove at 50%C and grinding in a mortar.
168

Efeitos do uso do biodiesel sobre propriedades do óleo lubrificante usado em um motor de ignição por compressão / Effects of the use of biodiesel on the properties of lubricating oil in a compression-ignition engine

Silva, Marcus Vinícius Ivo da 14 July 2006 (has links)
Dentro da seqüência natural de testes para validar o uso do biodiesel (éster etílico) misturado ao óleo diesel em maiores proporções no Brasil, este trabalho teve o objetivo de estudar os efeitos do uso de uma mistura combustível B10 (com concentração de 10% em volume de biodiesel diluído em óleo diesel) na degradação do óleo lubrificante de um motor de ignição por compressão, aspirado, de 1,9 L e de injeção indireta. Acoplado a um dinamômetro, o motor foi submetido à condição de velocidade constante de 2.500 rpm, sob carga variável, e abastecido com três combustíveis diferentes: óleo diesel puro, B10 de biodiesel de soja e B10 de biodiesel de soja e nabo forrageiro. Cada combustível alimentou o motor durante 30 horas. Para determinar a degradação resultante, selecionaram-se as propriedades do óleo lubrificante usado em cada etapa para serem analisadas (viscosidade, contaminação por água e presença de elementos). Os resultados revelaram que o uso de 10% volume dos dois tipos de biodiesel na mistura combustível não causou variação significante na concentração de elementos e nas propriedades físico-químicas do óleo lubrificante. / Adding to an ongoing sequence of tests aimed at validating the use of biodiesel (ethyl ester) mixed with diesel in higher proportions in Brazil, this study was conducted to investigate the effects of utilizing a B10 fuel mixture (10% volume biodiesel diluted in diesel) on the degradation of lubricating oil in an aspirated, indirect-injection, 1.9 L compression-ignition engine. Coupled to a dynamometer, the engine was operated at a constant speed of 2,500 rpm under variable load and run with three types of fuel: pure diesel, B10 soy biodiesel, and B10 soy and fodder turnip biodiesel. Each type of fuel fed the engine for 30 hours. To determine the resulting degradation, selected properties of the lubricating oil used in each run were analyzed (viscosity, contamination by water and presence of elements). The results revealed that the use of a 10% volume of either type of biodiesel in the fuel mixture did not lead to significant variation in the concentration of elements or in the physico-chemical properties of the lubricating oil.
169

Efeitos do uso do biodiesel sobre propriedades do óleo lubrificante usado em um motor de ignição por compressão / Effects of the use of biodiesel on the properties of lubricating oil in a compression-ignition engine

Marcus Vinícius Ivo da Silva 14 July 2006 (has links)
Dentro da seqüência natural de testes para validar o uso do biodiesel (éster etílico) misturado ao óleo diesel em maiores proporções no Brasil, este trabalho teve o objetivo de estudar os efeitos do uso de uma mistura combustível B10 (com concentração de 10% em volume de biodiesel diluído em óleo diesel) na degradação do óleo lubrificante de um motor de ignição por compressão, aspirado, de 1,9 L e de injeção indireta. Acoplado a um dinamômetro, o motor foi submetido à condição de velocidade constante de 2.500 rpm, sob carga variável, e abastecido com três combustíveis diferentes: óleo diesel puro, B10 de biodiesel de soja e B10 de biodiesel de soja e nabo forrageiro. Cada combustível alimentou o motor durante 30 horas. Para determinar a degradação resultante, selecionaram-se as propriedades do óleo lubrificante usado em cada etapa para serem analisadas (viscosidade, contaminação por água e presença de elementos). Os resultados revelaram que o uso de 10% volume dos dois tipos de biodiesel na mistura combustível não causou variação significante na concentração de elementos e nas propriedades físico-químicas do óleo lubrificante. / Adding to an ongoing sequence of tests aimed at validating the use of biodiesel (ethyl ester) mixed with diesel in higher proportions in Brazil, this study was conducted to investigate the effects of utilizing a B10 fuel mixture (10% volume biodiesel diluted in diesel) on the degradation of lubricating oil in an aspirated, indirect-injection, 1.9 L compression-ignition engine. Coupled to a dynamometer, the engine was operated at a constant speed of 2,500 rpm under variable load and run with three types of fuel: pure diesel, B10 soy biodiesel, and B10 soy and fodder turnip biodiesel. Each type of fuel fed the engine for 30 hours. To determine the resulting degradation, selected properties of the lubricating oil used in each run were analyzed (viscosity, contamination by water and presence of elements). The results revealed that the use of a 10% volume of either type of biodiesel in the fuel mixture did not lead to significant variation in the concentration of elements or in the physico-chemical properties of the lubricating oil.
170

Avaliação de micronutrientes e sua influência no metabolismo secundário de Bidens pilosa e Salvia officinalis, plantas usadas no tratamento de diabetes / Micronutrients evaluation and its influence on secondary metabolism of Bidens pilosa and Salvia officinalis, plants applied in diabetes treatment

Rodolfo Daniel Moreno Reis Gonçalves 13 November 2015 (has links)
O diabetes mellitus é uma doença que afeta o metabolismo de carboidratos, gorduras e proteínas e tem como aspectos característicos a hiperglicemia e a excreção da glicose pela urina. Estima-se que o número de casos da doença aumentará muito nos próximos anos, o que a torna preocupante para o sistema público de saúde dos países mais afetados. Além do uso de medicamentos alopáticos, tratamentos complementares como o uso de plantas medicinais pode contribuir para melhorar a qualidade de vida do paciente. Entre as ervas utilizadas, tanto no Brasil quanto em outras partes do mundo, encontram-se Bidens pilosa e Salvia officinalis. Os mecanismos responsáveis pela atividade antidiabética das plantas, geralmente estão associados aos seus metabólitos secundários, no entanto, a influência de micronutrientes não deve ser descartada. Estudos mostram que há uma correlação entre a concentração destes elementos com a presença e o desenvolvimento da doença. O objetivo deste trabalho foi estudar os elementos Cr, Fe, Mg, Mn, V e Zn em Bidens pilosa (picão) e Salvia officinalis (sálvia) cultivadas com tratamento normal (substrato comercial) e com adição dos elementos acima mencionados, e verificar a influência destes elementos na produção de metabólitos secundários que podem atuar como agentes hipoglicêmicos. A determinação e quantificação elementar foram feitas por meio da técnica de Análise por Ativação Neutrônica Instrumental, e para análise dos metabólitos secundários utilizou-se a técnica de Cromatografia Líquida de Alta Eficiência. O resultados indicaram que B. pilosa e S. officinalis podem ser usadas como fontes de Cr, Fe Mg, Mn, V e Zn. Foi observado que a B. pilosa absorveu maior quantidade de Fe no grupo tratamento, e que a S. officinalis foi capaz de acumular Zn nas folhas independente de ter ou não sido tratada. Quanto aos compostos do metabolismo secundário, os resultados indicaram que sua produção pelas plantas aparentemente não foi alterada pela adição da solução dos nutrientes. / Diabetes mellitus is a disease that affects the carbohydrates, lipids and proteins metabolism characterized by hyperglycemia and glucose excretion by urine. It is estimated that the number of cases of this disease will increase in the coming years, worrying the public health system of the most affected countries. Besides the use of allopathic medicine, complementary treatments such as the use of medicinal plants can contribute to improving the pacients quality of life. Among the herbs used, both in Brazil and in other countries, are Bidens pilosa and Salvia officinalis. The mechanisms responsible for antidiabetic activity of the plants, are usually associated with secondary metabolites, however, the influence of micronutrient content should not be discarded. Studies have shown that there is a correlation between the concentration of these elements and the presence and development of the disease. The objective of this work was to study the elements Cr, Fe, Mg, Mn, V and Zn concentration in Bidens pilosa (beggarticks) and Salvia officinalis (sage) cultivated with normal treatment (commercial substrate) and, with the addition of these elements, to verify their influence in the production of secondary metabolites that can act as hypoglycemic agents. The elemental determination and quantification were performed by means of Instrumental Neutron Activation Analysis technique. For the secondary metabolites analysis Liquid Chromatography High Performance technique was used. The results indicated that B. pilosa and S. officinalis may be used as sources of Cr, Fe, Mg, Mn, V and Zn. It was observed that B. pilosa absorbed a larger amount of Fe in the treatment group, and S. officinalis was able to accumulate Zn its in leaves whether treated or not. Considering the secondary metabolism compounds, the results indicated that its production by plants was apparently not altered by the addition of the nutrient solution.

Page generated in 0.0748 seconds