A tomografia computadorizada (CT) representa a maior fonte de exposição aos raios X médicos e seu uso continua crescendo rapidamente, devido aos aparelhos de última geração com alta resolução de contraste. Uma avaliação dos parâmetros que influenciam a dose absorvida na tomografia asseguram o controle de qualidade e aceitação do equipamento. Os protocolos de CT utilizam câmara de ionização e filme radiográfico para esta avaliação e pela primeira vez, neste trabalho, o dosímetro químico Fricke Benzóico Xilenol Gel (FBXG) foi utilizado. Este dosímetro ao ser irradiado, produz um complexo colorido (Fe^{+3}-AX) possível de ser medido através de técnicas ópticas, acústicas e de ressonância magnética. A leitura do filme e FBXG por fotografia, também foi empregada pela primeira vez neste trabalho indicando ser adequada. Da utilização do FBXG para avaliação do CT, foi possível obter os parâmetros de espessura de corte, homogeneidade de campo e curvas de isodose, além da promissora indicação dos índices de dose em tomografia. / Computed tomography now represents the single largest source of medical exposure and its use is increasing rapidly, because of new generation units and hight contrast image. The acceptance and quality control tests of this equipment can be inferred through some parameters that influence the absorbed dose, such as axial and transaxial dose profile and CT dose indexes. Although ionization chamber and radiographic films are indicated by protocols for these evaluations, in this present work, beside this two dosimeters, we use the chemical dosimeter Fricke Benzoic Xylenol Gel (FBXG). This dosimeter when irradiated produces a colored complex (Fe^{+3}-XO), that in this work was measured photographically to obtain the parameters, once this technique as well the FBXG are linearly dependent on the absorbed dose. This reading technique was adequate to obtain the calibration curve, the axial and transaxial dose profile for the FBXG, besides to let us visualize the future acquiring of tomographic dose indexes.

Um experimento foi realizado com o objetivo de avaliar diferentes alternativas nutricionais no controle de diarréia de leitões. Foram utilizados 128 leitões de uma linhagem comercial, desmamados com idade média de 21 dias, sendo metade de cada sexo. Os leitões foram distribuídos em 32 baias, sendo cada unidade experimental composta por quatro leitões. O delineamento experimental foi o de blocos ao acaso, com os animais distribuídos em oito tratamentos e quatro repetições de quatro animais (dois machos e duas fêmeas). Tratamentos: T1 - alto calcário, sem óxido de zinco, sem ácido benzóico; T2 - alto calcário, com óxido zinco, sem ácido benzóico; T3 - baixo calcário, sem óxido de zinco, sem ácido benzóico; T4 - baixo calcário, com óxido zinco, sem ácido benzóico; T5 - alto calcário, sem óxido zinco, com ácido benzóico; T6 - alto calcário, com óxido de zinco, com ácido benzóico; T7 - baixo calcário, sem óxido de zinco, com ácido benzóico; T8 - baixo calcário, com óxido de zinco, com ácido benzóico. As dietas foram fornecidas em dois períodos: de 1 a 14 dias pós-desmame (Fase I) e de 15 a 28 dias pós-desmame (Fase II). A partir do 29º dia os animais receberam uma mesma dieta até os 70 dias de idade. As características zootécnicas avaliadas foram: o ganho de peso, o consumo de ração, índice de conversão alimentar e a incidência de diarréia. Além disso, foram avaliadas a altura das vilosidades do duodeno, a profundidade das criptas e a relação altura de vilosidades/profundidade de cripta. Ao final do experimento, foi coletada a tíbia para a avaliação da densidade óssea. O óxido de zinco diminuiu a incidência de diarréia e foi mais eficiente em melhorar o GPMD e o CRMD de 1 a 14 dias pós-desmame. O ácido benzóico associado ao baixo calcário melhorou o GPMD de 15 a 28 dias pós-desmame e teve efeito positivo na morfologia duodenal. A diminuição do nível de calcário não prejudicou a densidade mineral óssea dos animais. / One trial was conducted to evaluate different nutritional alternatives for diarrhea control in weanling piglets. One hundred twenty eight piglets (half male and half female) were weaned with approximately 21 days of age. The piglets were distributed in 32 pens and each one was an experimental unit with four piglets. In a block design, the animals were distributed in eight treatments and four replications with four animals each (two male and two female). Treatments: T1 - high limestone, without zinc oxide and benzoic acid; T2 - high limestone, with zinc oxide and without benzoic acid; T3 - low limestone, without zinc oxide and benzoic acid; T4 - low limestone, with zinc oxide and without benzoic acid; T5 - high limestone, without zinc oxide and with benzoic acid; T6 - high limestone, with zinc oxide and benzoic acid; T7 - low limestone, without zinc oxide and with benzoic acid; T8 - low limestone, with zinc oxide and benzoic acid. The diets were given in two periods: d 1 - 14 postweaning (Phase I) and d 15 - 28 postweaning (Phase II). The animals were fed with common diet from d 29 until 70 days of age. Parameters evaluated were: body weight gain, fed conversion, and diarrhea incidence. In addition, duodenum\'s villus height, crypt depth, and villus height/crypt depth were evaluated. At the end of time trial, tibia was collected for bone density analyze. Zinc oxide reduced diarrhea incidence and improved GDW and DC from d 1 - 14 postweaning. Benzoic acid with low limestone level improved GDW from d 15 - 28 postweaning and duodenal morphology was affected positively. The lower level of limestone did not affect mineral bone density of the animals.

This diploma thesis deals with photoelectrochemical cells containing photoactive titanium dioxide anode and their use for photocatalytic degradation of organic compound from water solutions. The electrical properties of the produced photoelectrochemical cells were determined by the use of voltamperometric characteristics, the oxidation ability of the cells was monitored by measuring the fluorescence of the oxidative intermediates. To study these reactions, benzoic acid was used as the fluorescence probe for OH˙ radicals. The aim of the study was to study the influence of material composition and spatial arrangement of the cathode and the relationship between irradiation, current and rate of electrode processes.

Spherical agglomerates of benzoic acid crystals have been successfully prepared by drowning-out crystallization in three solvent partial miscible mixtures. Benzoic acid is dissolved in ethanol, bridging liquid is added and this mixture is fed to the agitated crystallizer containing water. Fine crystals are produced by crystallization of the substance, and the crystals are agglomerated by introduction of an immiscible liquid called the bridging liquid. The concentration of solute, agitation rate, feeding rate, amount of bridging liquid and temperature are found to have a significant influence on the physico-mechanical properties of the product. The product particle characterization includes the particle size distribution, morphology and mechanical strength. Many of the solvents such as chloroform, toluene, pentane, heptane, cyclo hexane, diethyl ether and ethyl acetate were used as bridging liquids. Among the selected solvents ethyl acetate and di ethyl ether could not form the spherical agglomerates. Characteristics of the particles are changing with the bridging liquid used. Range of the operation for spherical agglomeration is very narrow and was shown that only at certain conditions the spherical agglomerates are produced. Increased amount of bridging liquid, decrease in feeding rate and temperature causes the particle size to increase. Particle morphology depends on the bridging liquid used, amount of bridging liquid and the temperature. Particles look completely spherical from the experiments where toluene is used as bridging liquid. The mechanical strength of single agglomerates has been determined by compression in a materials testing machine, using a 10N load cell. For single particle compression an approximate estimation of the true stress is presented. Compression characteristics for single agglomerates are compared with data on particle bed compression. Low elastic recovery and high compressibility of the single particles and of bed of particles reveals that the spherical agglomerates prepared in this work have a plastic behavior which is expected to be favorable for direct tabletting. Some of the stress–strain curves are J-shaped with no clear fracturing of the particles, and are well correlated by an exponential–polynomial equation. / QC 20101119

Benzoyl peroxide (BPO) is a common bleaching agent used in wheat flour. Due to its ability to damage existing nutrients in food and potential adverse effect to health, BPO have been strictly banned as a food additive in several countries and regions, such as China and Europe. However, the United States specifies that BPO is generally recognized as safe (GRAS). So, the WHO/FAO created a Codex Alimentarius Commission (CAC) to regulate the international BPO usage standard. According to the CAC, it is restricted at 75 mg/kg or parts per million (ppm). BPO is very unstable and easily converts to benzoic acid (BA), which places the analytical challenge for accurate BPO quantification. The objective of this study is to develop a reliable method for BPO quantification in flour. Raman spectroscopy was first explored to detect BPO and BA on an aluminum foil slide. The result showed BPO and BA produced distinct Raman peaks that can be discriminated against. However, the sensitivity was not satisfactory to reach the regulation limit. To improve sensitivity, surface-enhanced Raman spectroscopy (SERS) was applied using silver nanoparticles as the substrate. Although the signals did enhance significantly using SERS, the characteristic peaks of BPO disappeared as BPO converted to BA during the sample preparation. We then went back to Raman spectroscopy but focused on optimizing the sample preparation to enhance the signal intensity. Using a hydrophobic surface (i.e., parafilm) which can hold the droplet and minimize the spread, the Raman signal was enhanced significantly after repeating multiple droplets on the same surface. A standard curve was created for BPO from 25 ppm to 250 ppm and for BA from 250 ppm to 1000 ppm, respectively. To detect BPO in wheat flour, we applied a more advanced Raman imaging instrument and focused on the analysis of Raman maps instead of spectra for the analysis of effect flour matrix to BPO extraction and detection. We firstly tried an in situ method, which scanned the pellet of flour spiked with different amounts of BPO without extraction. However, we could not detect BPO at 0.1% or lower in flour samples. We then tried an extraction method using acetonitrile as the solvent, which showed a lower detection limit compared to the in situ method. However, this extraction method yielded inconsistent results for BPO that is under 0.05% in flour. The extraction method developed was further improved with an evaporating step and a C18 solid phase extraction (SPE) spin column. This improved the extraction efficacy and provided a roughly 60% recovery percentage for detecting BPO in wheat flour without decomposing into BA. In conclusion, we developed a simple sample preparation protocol coupled with Raman spectroscopy to quantify BPO in flour without converting to BA, which would meet the regulation requirement. This method also shortened the experiment time including both sample preparation and detection time compared to current methods.

O extrato bruto (DCM:MeOH 2:1) das raízes de Piper crassinervium foi submetido a fracionamentos cromatográficos resultando no isolamento e identificação de oito substâncias, sendo estas uma flavanona (5,4\'-diidroxi-7-metoxiflavanona [isosakuranetina]), duas hidroquinonas preniladas (1,4-diidroxi-2-[3\',7\'-dimetil-1\'-oxo-2\'-E-6\'-octadienil]-benzeno e 1,4-diidroxi-2-[3\',7\'-dimetil-1\'-oxo-2\'-Z-6\'-octadienil]-benzeno), um cromeno (ácido-2-metil-2-[4\'-metil-3\'-pentenil]2H-1-benzopirano-6-carboxílico), um derivado prenilado do ácido benzóico (ácido 4-hidroxi-3-[3\',7\'-dimetil-1\'-oxo-octa-2\'-E-6\'-dienil]-benzóico), uma amida isobutílica (piperlonguminina) e duas amidas piperidínicas (piperina e diidropiperina). As substâncias isoladas tiveram suas estruturas químicas determinadas por experimentos de espectrometria de massas, RMN de 1H e 13C e comparadas com os dados da literatura. / The crude extracts of the roots of Piper crassinervium was submitted to chromatographic steps yielding eight compounds including a flavanone (5,4\'-dihydroxy-7-methoxyflavanone [isosakuranetin]), two prenylated hydroquinones (1,4-dihydroxy-2-[3\',7\'-dimethyl-1\'-oxo-2\'-E-6\'-octadienyl]-benzene and 1,4-dihydroxy-2-[3\',7\'-dimethyl-1\'-oxo-2\'-Z-6\'-octadienyl]-benzene), one chromene (2-methyl-2-[4\'-methyl-3\'-pentenyl]-2H-1-benzopyran-6-carboxylic acid), one prenylated derivative of benzoic acid (4-hydroxy-3-[3\',7\'-dimethil-1\'-oxo]2\'-E-6\'-octadienyl-benzoic acid), one isobutyl amide (piperlonguminine) and two piperidine amides (piperine and dihydropiperine). The structures of the isolated compounds were determined by mass spectrometry, 1H and 13C NMR data by comparison with the literature data.

Semi-batch crystallization experiments have been performedboth in a loop reactor and in stirred tank reactors.Hydrochloric acid was fed to a stirred solution of sodiumbenzoate, and benzoic acid immediately formed. Benzoic acid isformed in excess of the solubility making the solutionsupersaturated. The loop reactor is U-shaped. In one leg a propeller stirrerwas placed to circulate the solution and in the other a turbinestirrer was placed in front of the feed point to vary the localmixing intensity. The objective was to analyse the relativeimportance of different levels of mixing on the product sizedistribution. The importance of mixing as well as scaling-upeffects on the product size distribution were studied in threestirred tank reactors of volumes 2.5 L, 10 L, and 200 L. Thestirred tank reactors had different geometry and were equippedwith either a marine propeller or a pitched blade turbine. The weight mean size generally increases with increasingtotal feeding time and increasing mixing intensity. The weightmean size increases by locating an extra turbine impeller atthe feed point in the 10 L stirred tank reactor. The turbineimpeller provides the desired feed point mixing intensitywithout raising the mixing intensity of the whole tank. The weight mean size increases with decreasing feed pipediameter in the loop reactor and for low feed rates in the 10 Lstirred tank reactor. The weight mean size increasessignificantly by changing the feed pipe opening from circularto rectangular with a constant cross-sectional area at equalfeed rates. Backmixing is visually observed in the largest feedpipe diameter in the loop reactor, thus, reducing the weightmean size. However, backmixing is not considered to be adominant phenomenon in the present work. Mesomixing time constants have been calculated according tothe turbulent dispersion mechanism and the inertial-convectivemechanism. The time constants for mesomixing are generallylonger than the time constant for micromixing. Thus, the ratioof the mesomixing and the micromixing time constants shows aninfluence of mesomixing as is shown by the experimentalresults. The experimental results are best described by theinertial-convective disintegration mechanism showing that thefeed plume mixing increases with decreasing feed pipe diameterand increased feed point mixing. The weight mean size is not strongly affected by the reactorvolume. However, the mixing conditions in the reactors have astrong influence on the weight mean size. No suggestedscaling-up rule can satisfactorily predict the weight mean sizein the different volumes. No single physical parameter, such asthe local energy dissipation rate, the mean energy dissipationrate or the circulation time, can satisfactorily explain theexperimental results. A new dimensionless mixing parameter, TR,has been defined as the ratio of the total feeding time and themesomixing time constant. The mesomixing time constant isdefined as the shortest dimension of the feed pipe divided bythe resultant bulk velocity passing the feed pipe entrance. Theexperimental results from both the loop reactor and the stirredtank reactors of different volumes can be correlated with TR.The weight mean size increases with increasing TR. <b>Keywords</b>: reaction crystallization, precipitation,benzoic acid, macromixing, mesomixing, micromixing,semi-batch, loop reactor, backmixing, colour experiments,scaling-up. <b>Keywords</b>: reaction crystallization, precipitation,benzoic acid, macromixing, mesomixing, micromixing,semi-batch, loop reactor, backmixing, colour experiments,scaling-up.

<p>Semi-batch crystallization experiments have been performedboth in a loop reactor and in stirred tank reactors.Hydrochloric acid was fed to a stirred solution of sodiumbenzoate, and benzoic acid immediately formed. Benzoic acid isformed in excess of the solubility making the solutionsupersaturated.</p><p>The loop reactor is U-shaped. In one leg a propeller stirrerwas placed to circulate the solution and in the other a turbinestirrer was placed in front of the feed point to vary the localmixing intensity. The objective was to analyse the relativeimportance of different levels of mixing on the product sizedistribution. The importance of mixing as well as scaling-upeffects on the product size distribution were studied in threestirred tank reactors of volumes 2.5 L, 10 L, and 200 L. Thestirred tank reactors had different geometry and were equippedwith either a marine propeller or a pitched blade turbine.</p><p>The weight mean size generally increases with increasingtotal feeding time and increasing mixing intensity. The weightmean size increases by locating an extra turbine impeller atthe feed point in the 10 L stirred tank reactor. The turbineimpeller provides the desired feed point mixing intensitywithout raising the mixing intensity of the whole tank.</p><p>The weight mean size increases with decreasing feed pipediameter in the loop reactor and for low feed rates in the 10 Lstirred tank reactor. The weight mean size increasessignificantly by changing the feed pipe opening from circularto rectangular with a constant cross-sectional area at equalfeed rates. Backmixing is visually observed in the largest feedpipe diameter in the loop reactor, thus, reducing the weightmean size. However, backmixing is not considered to be adominant phenomenon in the present work.</p><p>Mesomixing time constants have been calculated according tothe turbulent dispersion mechanism and the inertial-convectivemechanism. The time constants for mesomixing are generallylonger than the time constant for micromixing. Thus, the ratioof the mesomixing and the micromixing time constants shows aninfluence of mesomixing as is shown by the experimentalresults. The experimental results are best described by theinertial-convective disintegration mechanism showing that thefeed plume mixing increases with decreasing feed pipe diameterand increased feed point mixing.</p><p>The weight mean size is not strongly affected by the reactorvolume. However, the mixing conditions in the reactors have astrong influence on the weight mean size. No suggestedscaling-up rule can satisfactorily predict the weight mean sizein the different volumes. No single physical parameter, such asthe local energy dissipation rate, the mean energy dissipationrate or the circulation time, can satisfactorily explain theexperimental results. A new dimensionless mixing parameter, TR,has been defined as the ratio of the total feeding time and themesomixing time constant. The mesomixing time constant isdefined as the shortest dimension of the feed pipe divided bythe resultant bulk velocity passing the feed pipe entrance. Theexperimental results from both the loop reactor and the stirredtank reactors of different volumes can be correlated with TR.The weight mean size increases with increasing TR.</p><p><b>Keywords</b>: reaction crystallization, precipitation,benzoic acid, macromixing, mesomixing, micromixing,semi-batch, loop reactor, backmixing, colour experiments,scaling-up.</p><p><b>Keywords</b>: reaction crystallization, precipitation,benzoic acid, macromixing, mesomixing, micromixing,semi-batch, loop reactor, backmixing, colour experiments,scaling-up.</p>

O extrato bruto (DCM:MeOH 2:1) das raízes de Piper crassinervium foi submetido a fracionamentos cromatográficos resultando no isolamento e identificação de oito substâncias, sendo estas uma flavanona (5,4\'-diidroxi-7-metoxiflavanona [isosakuranetina]), duas hidroquinonas preniladas (1,4-diidroxi-2-[3\',7\'-dimetil-1\'-oxo-2\'-E-6\'-octadienil]-benzeno e 1,4-diidroxi-2-[3\',7\'-dimetil-1\'-oxo-2\'-Z-6\'-octadienil]-benzeno), um cromeno (ácido-2-metil-2-[4\'-metil-3\'-pentenil]2H-1-benzopirano-6-carboxílico), um derivado prenilado do ácido benzóico (ácido 4-hidroxi-3-[3\',7\'-dimetil-1\'-oxo-octa-2\'-E-6\'-dienil]-benzóico), uma amida isobutílica (piperlonguminina) e duas amidas piperidínicas (piperina e diidropiperina). As substâncias isoladas tiveram suas estruturas químicas determinadas por experimentos de espectrometria de massas, RMN de 1H e 13C e comparadas com os dados da literatura. / The crude extracts of the roots of Piper crassinervium was submitted to chromatographic steps yielding eight compounds including a flavanone (5,4\'-dihydroxy-7-methoxyflavanone [isosakuranetin]), two prenylated hydroquinones (1,4-dihydroxy-2-[3\',7\'-dimethyl-1\'-oxo-2\'-E-6\'-octadienyl]-benzene and 1,4-dihydroxy-2-[3\',7\'-dimethyl-1\'-oxo-2\'-Z-6\'-octadienyl]-benzene), one chromene (2-methyl-2-[4\'-methyl-3\'-pentenyl]-2H-1-benzopyran-6-carboxylic acid), one prenylated derivative of benzoic acid (4-hydroxy-3-[3\',7\'-dimethil-1\'-oxo]2\'-E-6\'-octadienyl-benzoic acid), one isobutyl amide (piperlonguminine) and two piperidine amides (piperine and dihydropiperine). The structures of the isolated compounds were determined by mass spectrometry, 1H and 13C NMR data by comparison with the literature data.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this dissertation was to evaluate the performance of lactating sows and their piglets fed with high moisture corn diets with or without acidifiers. Fifteen sows of commercial genetic lines were used in a randomized complete block with three treatments (negative control diet elaborated each 24h; control diet with 0.5% of benzoic acid elaborated each 24h; control diet with 0.5% of fumaric acid elaborated each 24h) with five replications each. Diets elaborated with high moisture corn with benzoic or fumaric acids did not modify (P>0.05) the backfat thickness. The average daily feed intake (7.93kg/NM) of lactating sows was not influenced (P>0.05) by treatments. The average daily weight gain (0.22kg) and average weaning live weight (6.2kg) of piglets were not influenced (P>0.05) by diets with benzoic or fumaric acids. The addition of fumaric acid in diets of lactation sows decreased (P<0.05) the liquid feces frequency in piglets comparated with negative control diet. The addition of acidifiers in diets containing high moisture corn does not alter performance of lactating sows neither their piglets. / O objetivo desta dissertação foi avaliar o desempenho de porcas lactantes e suas leitegadas alimentadas com dietas contendo silagem de grãos úmidos de milho com ou sem acidificantes. Foram utilizadas quinze porcas de genética comercial em um delineamento de blocos ao acaso com três tratamentos (dieta controle negativo elaborada a cada 24h; dieta com adição de 0,5% de ácido benzóico elaborada a cada 24h e dieta com adição de 0,5% de ácido fumárico elaborada a cada 24h) com cinco repetições cada. As dietas elaboradas com silagem de grãos úmidos de milho com ácidos benzóico ou fumárico não alteraram (P>0,05) a espessura de toicinho. O consumo diário de alimento das porcas lactantes foi de 7,93kg/MN não variando (P>0,05) entre os tratamentos. O ganho médio diário de peso dos leitões foi de 0,22kg, não variando (P>0,05) entre os tratamentos. O peso vivo médio dos leitões ao desmame foi de 6,2kg não diferindo (P>0,05) entre leitões de porcas lactantes alimentadas com dietas com ácido benzóico ou fumárico. No período total de 21 dias, a adição de ácido fumárico na dieta de porcas lactantes diminuiu em 30% (P<0,05) a freqüência de fezes líquidas dos leitões em relação à dieta controle. A adição de ácidos fumárico e benzóico em dietas elaboradas com silagem de grãos úmidos de milho não alteram os desempenhos de porcas lactantes e nem o de suas leitegadas.