The goal of this study is to determine whether or not there is an appreciable difference between concentrations of various metal ions present in conventionally grown and processed and organically grown and processed baby foods. Two prominent, commercially available brands were chosen to undergo comparative studies between both their own conventional and organic varieties of second stage green beans and carrots. Samples were tested for cadmium, calcium, iron, lead, nickel, and zinc. Two containers of each variety of baby food were sampled in triplicate, with purchases of foods being made in separate areas to ensure that each set came from different batches. Samples were digested with nitric acid, appropriately diluted, and analyzed for metal content by flame atomic absorption spectroscopy with the regular standard calibration curve and standard addition method. There was little overall difference in metal content between the conventional and organic foods tested.

The concentrations of heavy metals (Cd, Cu, Fe, Ni, Pb, Zn) were measured in water, and fish samples caught from the pond at Fishery Park in Unicoi County, TN. The water samples were collected once a week for 8 weeks. The amounts of metals in the muscle tissues, gill, and liver of the two fish species were measured. This was to determine if any correlation exists between the metal contents in water and those in the fish samples. The concentration ranges for the heavy metals found in the water samples are as follows: Zn 0.04-0.13; Cu, 0.00-0.00; Pb, 0.00-0.59; Cd, 0.0067-0.0071; Fe, 0.208-0.512; and Ni, 0.044-0.270 ppm. The concentration range for the heavy metals found in the fish tissues are as follows: Zn 0.0-0.48; Cu, 0.00-0.00; Pb, 0.00-0.43; Cd, 0.00-99.7; Fe, 25.7-1245.5; and Ni, 0.00-268.5 ppm. There was a strong correlation found between the water and fish tissue samples.

This study aims to determine the distribution of particulates carrying heavy metals at selected sites on a college campus using dandelion leaves as collectors. As a comparison, sites far away from the campus surrounding Bristol Motor Speedway Car Racing Stadium were also monitored. To reduce the probability of memory effects from the long-term atmospheric deposition or absorption of metals from soil a seasonal plant, dandelion, was used to monitor the metal contents. The metals monitored are cadmium, calcium, copper, chromium, iron, lead, and zinc. Fourteen sites were monitored and samples were collected once a week initially (growing time of the plant), and later at 4-week interval from 28th March to 31st August of 2007. The metal contents of the nitric acid digested and appropriately diluted samples were determined by flame atomic absorption spectrometry using the regular standard calibration curve and also the standard addition method. From the results obtained, and the careful log of the weather and human activities at the different sites, it is concluded that human activities played a major role in the distribution of metal-laden particulates. Also dandelion leaves were proven to be viable collectors of these particulates without memory effects and as indicators of current particulates generated rather than a long-term cumulative one.

Выпускная квалификационная работа включает в себя: изучение принципа работы и устройства оптических спектрофотометров; проведение серии практических измерений с помощью спектрофотометра ColorMunki и, путем математической обработки результатов измерений вычислении погрешности работы спектрофотометра. / This qualifying work includes: the study of the principle of operation of spectrophotometers and optical devices; conducting practical series of measurements using a spectrophotometer and ColorMunki, by mathematical processing of the measurement results error calculating spectrophotometer operation.

Выпускная квалификационная работа включает в себя: поиск и анализ информации, связанной с конструкцией и техническими характеристиками данного прибора; поиск и анализ информации по методам поверки полиграфических спектрофотометров; исследование спектра источника опорного источника света и путем математической обработки результатов измерений вычислить погрешность работы спектрофотометра. / This qualifying work includes: search and analysis of information related to the design and specifications of this device; search and analysis of information on methods for verification printing spectrophotometers; a study of the spectrum of light source and the reference source by mathematical processing of measurements to calculate the error operation of the spectrophotometer.

В данной магистерский диссертаций было рассмотрена проблема погрешности спектрофотометра X-Rite i1 Pro2. Значительное внимание уделяется то-что производитель не опубликует полная информация о погрешности. Проведены оригинальные эксперименты по измерению спектральной интенсивности опорного источника спектрофотометра i1 Pro и оценке погрешности однократного измерения. Впервые обнаружен временной дрейф регистрируемых спектральных данных и периодический характер этого дрейфа. Установлено, что без учета временного дрейфа разброс регистрируемых монохроматических данных подчиняется нормальному закону. Получена спектральная зависимость среднего квадратичного отклонения при условии аналитической компенсации дрейфа. Высказано предположение, что величина СКО обратно пропорциональна относительной спектральной интенсивности опорного источника. / A problem of spectrophotometer X-Rite i1 Pro2 error determination has been discussed in this thesis. Considerable attention is paid to that the manufacturer does not publish complete information about the error. Conducted the original experiments to measure the spectral intensity of the reference source i1 Pro spectrophotometer and evaluation of single measurement error. For the first time found a temporary drift recorded spectral data and the periodic nature of this drift. It was found that without regard to the spread of drift detected monochromatic data is subject to the normal law. The spectral dependence of the standard deviation, provided analytical drift compensation. It is suggested that the value of standard deviation is inversely proportional to the relative spectral intensity of the reference source.

No description available.

Recently, several spectrometers for small volume measurements in order of microliter have been introduced. They are primarily intended for protein determination (or determination of proteins and nucleic acids in one measurement) by direct spectrophotometry or other spectral methods. One of such instruments is the NanoVueTM Plus (GE Healthcare). In this work, we first tried to characterize the instrument in general terms (stability) and to optimize measurement condititions (sample volume). Proteins have been determined by direct spectrophotometry using internal programs of the instrument, data were controlled by an independent computation. We studied also influence of differences in composition of various proteins on the results. According to the results of this Thesis, the most accurate values could be obtained using the internal program E 1%, using the E 1% value from an experiment. On the other hand, the program Protein UV is producing often inaccurate values, strongly infleunced by the protein amino acid composition. Keywords: protein determination, spectrophotometer NanoVueTM Plus, influence of amino acid composition

A estética tornou-se de fundamental importância nas últimas décadas, fazendo com que houvesse uma grande evolução nos materiais dentários e técnicas restauradoras para atender a esta exigência. As cerâmicas odontológicas são materiais estéticos e biocompatíveis, podendo ser uma ótima alternativa quando aplicadas a casos apropriadamente selecionados. O sucesso estético de uma restauração de cerâmica depende da caracterização de superfície, da integridade marginal, da forma anatômica e da coloração. O presente estudo teve o objetivo de avaliar a estabilidade de cor de dois tipos de restaurações em cerâmica odontológica, metalocerâmica e livre de metal, submetidas a múltiplos ciclos de queimas. Foram realizados 60 corpos-de-prova, sendo 30 na forma de metalocerâmicas e 30 livres de metal que foram divididas em três grupos de 10 amostras cada, sendo confeccionadas em duas, três e quatro queimas respectivamente. As leituras de cor foram realizadas em espectrofotômetro PCB 6807 BYK GARDNER antes e após envelhecimento artificial acelerado (Comexim Matérias Primas). Analisando-se inicialmente a influência do número de queimas sobre a cor da cerâmica odontológica, houve diferenças estatisticamente significantes para as coordenadas L* nas amostras metalocerâmicas, sendo que o grupo de 3 queimas foi o que apresentou diferenças em relação aos outros dois grupos. Para as amostras livres de metal, houve diferenças nas coordenadas L*, a* e b*, com comportamentos heterogêneos para as 3 coordenadas. Os resultados indicaram diferenças estatisticamente significantes na variação total de cor (&#8710;E) para as amostras de 3 e 4 queimas, comparando-se os tipos de restauração. Quando analisada a interferência do número de queimas de um mesmo tipo de restauração, não houve diferença estatisticamente significante para a amostra livre de metal. Para a amostra metalocerâmica, houve apenas diferença estatisticamente significante entre as amostras que receberam 2 e 3 queimas. Para a variação total nas coordenadas L*, a* e b* também houve variação de valores para os dois tipos de amostras e em relação aos ciclos de queimas. Concluiu-se que as pequenas diferenças estatisticamente significantes encontradas em alguns grupos não foram visíveis ao olho humano e portanto sem qualquer significado clínico (&#8710;E < 3,3). Além disso, os múltiplos ciclos de queima e o envelhecimento acelerado não modificaram de forma significativa a estabilidade de cor da cerâmica nas formas em que foi empregada (&#8710; < 1). / Esthetics has become essential over the past few decades, causing dental materials and restorative techniques to evolve significantly. Dental ceramics are esthetic and biocompatible materials which may be an excellent alternative for properly selected cases. The esthetic success of a ceramic’s restoration depends on surface characterization, marginal integrity, anatomic form, and color. This study aimed to assess the color stability of two types of dental ceramic restorations, metalloceramic and metal-free, submitted to multiple burn cycles. Sixty specimens were fabricated: 30 metalloceramic and 30 metal-free. The specimens were divided into 3 groups (n= 10) according to the number of burns (2, 3, and 4 burns). Color readings were performed using a PCB 6807 BYK GARDNER spectrophotometer before and after artificial accelerated aging (Comexim Raw Materials). By analyzing the influence of the number of burns over the dental ceramic’s color, statistically significant differences were found for the coordinate L* for the metalloceramic specimens, in the group of 3 burns, in relation to the other 2 groups. For the metal-free specimens, there were differences for the coordinates L*, a*, and b*, with heterogeneous compartments for the 3 coordinates. The results revealed statistically significant differences for total color variation (&#8710;E) for the 3 burns group, in comparison to the other types of restoration. When analyzing the specimens of a single type of material, in terms of the interference of the number of burns, the metal-free samples showed no statistically significant differences, whereas the metalloceramic samples showed difference only between those that received 2 and 3 burns. For the total variation of coordinates L*, a*, and b*, both materials showed a variation in those values and in relation to burn cycles. The small statistically significant differences found in some groups are invisible and present no clinical meaning (&#8710;E<3.3). In addition, the multiple burn cycles and accelerated aging did not modify significantly the ceramic’s color stability (&#8710;<1).

A estética tornou-se de fundamental importância nas últimas décadas, fazendo com que houvesse uma grande evolução nos materiais dentários e técnicas restauradoras para atender a esta exigência. As cerâmicas odontológicas são materiais estéticos e biocompatíveis, podendo ser uma ótima alternativa quando aplicadas a casos apropriadamente selecionados. O sucesso estético de uma restauração de cerâmica depende da caracterização de superfície, da integridade marginal, da forma anatômica e da coloração. O presente estudo teve o objetivo de avaliar a estabilidade de cor de dois tipos de restaurações em cerâmica odontológica, metalocerâmica e livre de metal, submetidas a múltiplos ciclos de queimas. Foram realizados 60 corpos-de-prova, sendo 30 na forma de metalocerâmicas e 30 livres de metal que foram divididas em três grupos de 10 amostras cada, sendo confeccionadas em duas, três e quatro queimas respectivamente. As leituras de cor foram realizadas em espectrofotômetro PCB 6807 BYK GARDNER antes e após envelhecimento artificial acelerado (Comexim Matérias Primas). Analisando-se inicialmente a influência do número de queimas sobre a cor da cerâmica odontológica, houve diferenças estatisticamente significantes para as coordenadas L* nas amostras metalocerâmicas, sendo que o grupo de 3 queimas foi o que apresentou diferenças em relação aos outros dois grupos. Para as amostras livres de metal, houve diferenças nas coordenadas L*, a* e b*, com comportamentos heterogêneos para as 3 coordenadas. Os resultados indicaram diferenças estatisticamente significantes na variação total de cor (&#8710;E) para as amostras de 3 e 4 queimas, comparando-se os tipos de restauração. Quando analisada a interferência do número de queimas de um mesmo tipo de restauração, não houve diferença estatisticamente significante para a amostra livre de metal. Para a amostra metalocerâmica, houve apenas diferença estatisticamente significante entre as amostras que receberam 2 e 3 queimas. Para a variação total nas coordenadas L*, a* e b* também houve variação de valores para os dois tipos de amostras e em relação aos ciclos de queimas. Concluiu-se que as pequenas diferenças estatisticamente significantes encontradas em alguns grupos não foram visíveis ao olho humano e portanto sem qualquer significado clínico (&#8710;E < 3,3). Além disso, os múltiplos ciclos de queima e o envelhecimento acelerado não modificaram de forma significativa a estabilidade de cor da cerâmica nas formas em que foi empregada (&#8710; < 1). / Esthetics has become essential over the past few decades, causing dental materials and restorative techniques to evolve significantly. Dental ceramics are esthetic and biocompatible materials which may be an excellent alternative for properly selected cases. The esthetic success of a ceramic’s restoration depends on surface characterization, marginal integrity, anatomic form, and color. This study aimed to assess the color stability of two types of dental ceramic restorations, metalloceramic and metal-free, submitted to multiple burn cycles. Sixty specimens were fabricated: 30 metalloceramic and 30 metal-free. The specimens were divided into 3 groups (n= 10) according to the number of burns (2, 3, and 4 burns). Color readings were performed using a PCB 6807 BYK GARDNER spectrophotometer before and after artificial accelerated aging (Comexim Raw Materials). By analyzing the influence of the number of burns over the dental ceramic’s color, statistically significant differences were found for the coordinate L* for the metalloceramic specimens, in the group of 3 burns, in relation to the other 2 groups. For the metal-free specimens, there were differences for the coordinates L*, a*, and b*, with heterogeneous compartments for the 3 coordinates. The results revealed statistically significant differences for total color variation (&#8710;E) for the 3 burns group, in comparison to the other types of restoration. When analyzing the specimens of a single type of material, in terms of the interference of the number of burns, the metal-free samples showed no statistically significant differences, whereas the metalloceramic samples showed difference only between those that received 2 and 3 burns. For the total variation of coordinates L*, a*, and b*, both materials showed a variation in those values and in relation to burn cycles. The small statistically significant differences found in some groups are invisible and present no clinical meaning (&#8710;E<3.3). In addition, the multiple burn cycles and accelerated aging did not modify significantly the ceramic’s color stability (&#8710;<1).