Lesões de cárie em esmalte submetidas a diferentes tratamentos com flúor tópico in situ

O presente estudo teve por objetivo avaliar se a aplicação tópica de flúor fosfato acidulado (FFA) em alta concentração tem efeito adicional no controle de lesões de esmalte, comparado ao uso de dentifrício fluoretado (baixa concentração). A freqüência de FFA como auxiliar no tratamento de lesões de cárie e a deposição de flúor no esmalte após diferentes aplicações de flúor am alta e baixa concentração também foram avaliadas. Para tanto, 5 indivíduos utilizaram, por 42 dias, próteses parciais removíveis inferiores contendo blocos de esmalte bovino desmineralizados. Os espécimes de esmalte forma divididos em 5 grupos: (1) escovação 3 vezes ao dia com dentifrício fluoretado (DF) (1100 ppm F), (2) DF+1 aplicação tópica FFA (12300 ppm F), (3) DF+2 FFA, (4) DF+3 FFA, e 5) DF+4 FFA. O intervalo entre as aplicações foi de uma semana. Cinco blocos hígidos e 5 blocos desmineralizados foram utilizados como controle e não foram submetidos ao período intraoral. As alterações clínicas foram registradas com relação à textura, coloração e brilho superficiais. Análises de microdureza superficial (MS) e em cortes longitudinais (MCL), de rugosidade superficial (RS) e de conteúdo de flúor depositado no esmalte foram realizadas. Modificações clínicas semelhantes de coloração foram observadas em todos os grupos após formação da lesão in vitro, apesar da ausência de mudanças na textura e brilho superficiais. Após escovação e tratamento com flúor, todos os blocos desmineralizados (esbranquiçados), independentemente do tratamento, tornaram-se mais amarelados. Não foram detectadas mudanças na textura e brilho superficiais. Os valores de MS e de conteúdo de flúor aumentaram (p<0,05) em relação aos blocos demineralizados somente a partir de 2 FFA. Os valores de MCL não mostraram diferenças entre os blocos tratados e os desmineralizados em qualquer distância da superfície do esmalte. Os grupos DF+3 FFA e DF+ 4 FFA foram os únicos capazes de aumentar os valores de MS em relação aos blocos desmineralizados. Estes tratamentos levaram a um aumento significativo de flúor solúvel e insolúvel comparado aos espécimes hígidos e desmineralizados. Ainda que todas as lesões tenham sido controladas clinicamente e não mostrem diferenças de microdureza, parece que aquelas tratadas com maior número de FFA produziram um maior reservatório de flúor disponível para inibir novos processos de desmineralização.

Avaliação in situ da composição do biofilme e da progressão de lesões cariosas em esmalte de dentes decíduos e permanentes humanos, na presença e na ausência de dentifrício fluoretado

Evidências na literatura sugerem que a velocidade de progressão de cárie pode ser influenciada por diversos fatores, entre eles as peculiaridades químicas, morfológicas e fisiológicas pertinentes aos dentes decíduos e permanentes. Estas informações são fundamentais para a correta abordagem clínica do paciente odontopediátrico, principalmente quando esta não for invasiva. Este estudo in situ avaliou a progressão de lesões cariosas em esmalte de dentes decíduos e permanentes, em um mesmo desenho experimental, na presença e na ausência de dentifrício fluoretado (1100 ppm NaF). Onze voluntários, em duas fases distintas, utilizaram um dispositivo palatino de acrílico contendo blocos de esmalte decíduos e permanentes. Estes blocos foram tratados com sacarose 20%, 8x/dia, por 7, 14 e 21 dias. O biofilme formado sobre os blocos dentários foi coletado para análise bioquímica e as perdas minerais dos mesmos foram acessadas através da inspeção visual (IV), microdureza transversa (∆Z) e microscopia de luz polarizada (MLP). Os resultados foram submetidos ao teste de Tukey (p=0,05) e mostraram que o biofilme formado na presença de dentifrício fluoretado apresentou maiores (p<0,05) concentrações de Ca, Pi, F que o tratado com dentifrício placebo. A concentração de PI foi significativamente maior no biofilme tratado com dentifrício placebo. Os fatores substrato, dentifrício e tempo influenciaram de forma significativa nas perdas minerais mensuradas através da IV, ∆Z e MLP. Em todos os períodos e fases estudadas, a velocidade de progressão de cárie no esmalte do dente decíduo foi maior que no permanente (p<0,05).

Polimerização de propeno com catalisadores metalocênicos via suportação in-situ utilizando SMAO como suporte

Os catalisadores metalocênicos Me2Si(Ind)2ZrCl2 e Me2Si(2-Me-Ind)2ZrCl2 foram suportados in-situ sobre SMAO e empregados na polimerização de propeno na presença de alquilalumínios tais como TEA, IPRA ou TIBA. Os resultados obtidos demonstraram que o tipo e a concentração de alquilalumínio presente no meio reacional influenciaram tanto a atividade catalítica quanto as propriedades dos polímeros gerados. Os polímeros obtidos com o catalisador suportado in-situ apresentaram propriedades distintas das obtidas no polímero gerado através da polimerização homogênea, além de morfologia controlada, confirmando que de fato a polimerização ocorreu sobre a superfície do SMAO. Através da deconvolução das curvas de GPC foi constatado o aumento do número de tipos de sítios ativos no sistema catalítico suportado in-situ, resultado que também confirmou a heterogeneização do catalisador sobre o suporte. Com o auxílio de cálculos teóricos e da deconvolução das curvas de GPC foi possível propor estruturas para os sítios ativos dos sistemas homogêneo metaloceno/MAO e heterogêneo (suportado in-situ) metaloceno/SMAO/alquilalumínio. Quando eteno foi utilizado como monômero, o comportamento do sistema catalítico metaloceno/SMAO/alquilalumínio suportado in-situ foi distinto do obtido com propeno. O catalisador Me2Si(Ind)2ZrCl2 suportado ex-situ sobre SMAO através de técnicas convencionais de suportação foi avaliado por EXAFS e foi constatado que a vizinhança eletrônica do zircônio é influenciada pela razão Zr/SMAO. Os resultados obtidos por EXAFS foram correlacionados com a variação na atividade catalítica na polimerização de eteno em função da alteração na razão Zr/SMAO.

New bacterial cellulose nanocomposites prepared by in situ radical polymerization of methacrylate monomers

Bacterial cellulose/polymethacrylate nanocomposites have received attention in numerous areas of study and in a variety of applications. The attractive properties of methacrylate polymers and bacterial cellulose, BC, allow the synthesis of new nanocomposites with distinct characteristics. In this study, BC/poly(glycidylmethacrylate) (BC/PGMA) and BC/poly(ethyleneglycol)methacrylate (BC/PPEGMA) nanocomposites were prepared through in situ free radical polymerization of GMA and PEGMA, respectively. Ammonium persulphate (APS) was used as an initiator and N,N’methylenebisacrilamide (MBA) was used as a crosslinker in BC/PGMA. Chemical composition, morphology, thermal stability, water absorption, mechanic and surface properties were determined through specific characterization techniques. The optimal polymerization was obtained at (1:2) for BC/PGMA, (1:2:0.2) ratio for BC/GMA/MBA and (1:20) for BC/PPEGMA, with 0.5% of initiator at 60 ºC during 6 h. A maximum of 67% and 87% of incorporation percentage was obtained, respectively, for the nanocomposites BC/PGMA/MBA and BC/PPEGMA. BC/PGMA nanocomposites exhibited an increase of roughness and compactation of the three-dimensional structure, an improvement in the thermal and mechanical properties, and a decrease in their swelling ability and crystallinity. On the other hand, BC/PPEGMA showed a decrease of stiffness of three-dimensional structure, improvement in thermal and mechanical properties, an increase in their swelling ability and a decrease the crystallinity. Both BC/polymethacrylate nanocomposites exhibited a basic surface character. The acid treatment showed to be a suitable strategy to modifiy BC/PGMA nanocomposites through epoxide ring-opening reaction mechanism. Nanocomposites became more compact, smooth and with more water retention ability. A decrease in the thermal and mechanical proprieties was observed. The new nanocomposites acquired properties useful to biomedical applications or/and removal of heavy metals due to the presence of functional groups.

Construção de um aparato experimental para monitoramento in situ da deposição de filmes finos de titânio por magnetron sputtering

The technique of surface coating using magnetron sputtering is one of the most widely used in the surface engineering, for its versatility in obtaining different films as well as in the micro / nanometric thickness control. Among the various process parameters, those related to the active species of the plasma are of the most fundamental importance in the mechanism and kinetics of deposition. In order to identify the active species of the plasma, parameters such as gas flow, pressure and density of electric power were varied during titanium coating on glass substrate. By flowing argon gas of 10, 20, 30, 40 and 50 sccm (cubic centimeters per minute) for each gas flow a sequential scan of the electric current of 0.10, 0.20, 0.30, 0.40 , 0.50 A. The maximum value of 0.50 A was chosen based both on literature data and on limitations of the equipment. The monitoring of plasma species present during the deposition was carried out in situ by the technique of optical emission spectroscopy (OES) through the spectrometer Ocean Optics USB2000 Series. For this purpose, an apparatus was developed to adapt the OES inside the plasma reactor to stay positioned closest to the target. The radiations emitted by the species were detected by an optical fiber placed behind the glass substrate and their intensities as a function of wavelength were, displayed on a monitor screen. The acquisition time for each condition of the plain parameters was related to the minima of spectral lines intensities due to the film formed on the substrate. The intensities of different emission lines of argon and titanium were then analyzed as a function of time, to determine the active species and estimate the thickness of the deposited films. After the deposition, the coated glasses thin films were characterized by optical transmittance through an infrared laser. It was found that the thickness and deposition rate determined by in situ analysis were consistent with the results obtained by laser transmittance

Estudo do processo de combustão in-situ usando poços horizontais como produtores de óleo (Toe-to-Hell Air Injection)

The method "toe-to-heel air injection" (THAITM) is a process of enhanced oil recovery, which is the integration of in-situ combustion with technological advances in drilling horizontal wells. This method uses horizontal wells as producers of oil, keeping vertical injection wells to inject air. This process has not yet been applied in Brazil, making it necessary, evaluation of these new technologies applied to local realities, therefore, this study aimed to perform a parametric study of the combustion process with in-situ oil production in horizontal wells, using a semi synthetic reservoir, with characteristics of the Brazilian Northeast basin. The simulations were performed in a commercial software "STARS" (Steam, Thermal, and Advanced Processes Reservoir Simulator), from CMG (Computer Modelling Group). The following operating parameters were analyzed: air rate, configuration of producer wells and oxygen concentration. A sensitivity study on cumulative oil (Np) was performed with the technique of experimental design, with a mixed model of two and three levels (32x22), a total of 36 runs. Also, it was done a technical economic estimative for each model of fluid. The results showed that injection rate was the most influence parameter on oil recovery, for both studied models, well arrangement depends on fluid model, and oxygen concentration favors recovery oil. The process can be profitable depends on air rate

Estudo do processo de combustão in-situ em reservatórios maduros de óleos médios e leves (high pressure air injection)

Nearly 3 x 1011 m3 of medium and light oils will remain in reservoirs worldwide after conventional recovery methods have been exhausted and much of this volume would be recovered by Enhanced Oil Recovery (EOR) methods. The in-situ combustion (ISC) is an EOR method in which an oxygen-containing gas is injected into a reservoir where it reacts with the crude oil to create a high-temperature combustion front that is propagated through the reservoir. The High Pressure Air Injection (HPAI) method is a particular denomination of the air injection process applied in light oil reservoirs, for which the combustion reactions are dominant between 150 and 300°C and the generation of flue gas is the main factor to the oil displacement. A simulation model of a homogeneous reservoir was built to study, which was initially undergone to primary production, for 3 years, next by a waterflooding process for 21 more years. At this point, with the mature condition established into the reservoir, three variations of this model were selected, according to the recovery factors (RF) reached, for study the in-situ combustion (HPAI) technique. Next to this, a sensitivity analysis on the RF of characteristic operational parameters of the method was carried out: air injection rate per well, oxygen concentration into the injected gas, patterns of air injection and wells perforations configuration. This analysis, for 10 more years of production time, was performed with assistance of the central composite design. The reservoir behavior and the impacts of chemical reactions parameters and of reservoir particularities on the RF were also evaluated. An economic analysis and a study to maximize the RF of the process were also carried out. The simulation runs were performed in the simulator of thermal processes in reservoirs STARS (Steam, Thermal, and Advanced Processes Reservoir Simulator) from CMG (Computer Modelling Group). The results showed the incremental RF were small and the net present value (NPV) is affected by high initial investments to compress the air. It was noticed that the adoption of high oxygen concentration into the injected gas and of the five spot pattern tends to improve the RF, and the wells perforations configuration has more influence with the increase of the oil thickness. Simulated cases relating to the reservoir particularities showed that smaller residual oil saturations to gas lead to greater RF and the presence of heterogeneities results in important variations on the RF and on the production curves

Estudo dos parâmetros operacionais do processo de combustão in situ em reservatório de petróleo pesado

The occurrence of heavy oil reservoirs have increased substantially and, due to the high viscosity characteristic of this type of oil, conventional recovery methods can not be applied. Thermal methods have been studied for the recovery of this type of oil, with a main objective to reduce its viscosity, by increasing the reservoir temperature, favoring the mobility of the oil and allowing an increasing in the productivity rate of the fields. In situ combustion (ISC) is a thermal recovery method in which heat is produced inside the reservoir by the combustion of part of the oil with injected oxygen, contrasting with the injection of fluid that is heated in the surface for subsequent injection, which leads to loss heat during the trajectory to the reservoir. The ISC is a favorable method for recovery of heavy oil, but it is still difficult to be field implemented. This work had as an objective the parametric analysis of ISC process applied to a semi-synthetic reservoir with characteristics of the Brazilian Northeast reservoirs using vertical production and vertical injection wells, as the air flow injection and the wells completions. For the analysis, was used a commercial program for simulation of oil reservoirs using thermal processes, called Steam, Thermal and Advanced Processes Reservoir Simulator (STARS) from Computer Modelling Group (CMG). From the results it was possible to analyze the efficiency of the ISC process in heavy oil reservoirs by increasing the reservoir temperature, providing a large decrease in oil viscosity, increasing its mobility inside the reservoir, as well as the improvement in the quality of this oil and therefore increasing significantly its recovered fraction. Among the analyzed parameters, the flow rate of air injection was the one which had greater influence in ISC, obtaining higher recovery factor the higher is the flow rate of injection, due to the greater amount of oxygen while ensuring the maintenance of the combustion front

In situ differentiation of labile/inert metal species in Brazilian tropical rivers by means of a time-controlled batch-procedure based on TEPHA resin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação de diferentes formas de preservação e desenvolvimento in situ de folículos ovarianos pré-antrais caprinos

This study evaluated the effect of indole-3-acetic acid (IAA) in the activation of goats preantral follicles (FOPA). Were used four pairs of ovaries of adult mixed breed goats. Each ovarian pair was divided into 23 fragments. One fragment was fixed for histology and other fragment was using to follicular isolation procedure. The remaining fragments were cultured in 1.0 ml of Minimum Essential Medium (MEM) or MEM supplemented with IAA at concentrations of 10, 40, 100, 500 or 1000 ng/mL. The in vitro culture was performed at 39°C in incubator with 5% CO2 for 1, 3 and 5 days. After in vitro culture was evaluated histological integrity and viability of FOPA. The addition of 100 ng/ml of IAA to MEM showed a significant increase in follicles transition in the third day of in vitro culture, characterizing follicular activation. Moreover, this concentration was obtained maintaining the histological integrity of PAF by the fifth day of in vitro culture. The viability test confirmed the results of histology. Thus, we conclude that IAA can promote the activation of goats FOPA

Degradabilidade in situ e parâmetros ruminais em bovinos alimentados com dietas balanceadas para diferentes ganhos de peso e potenciais de fermentação microbiana

Um experimento foi realizado com o objetivo de avaliar os parâmetros ruminais, a produção de ácidos graxos voláteis e a degradabilidade in situ em tourinhos Santa Gertrudes canulados no rúmen alimentados com dietas compostas de feno de capim-marandu e concentrado. Empregou-se o delineamento em quadrado latino 4 ´ 4, no qual os tratamentos foram compostos dos concentrados, ajustados para ganho de peso corporal (GPC) diário de 0,5 e 1 kg/animal e potencial de fermentação microbiana (y) de 9,5 e 11 g de proteína bruta microbiana/MJ energia metabolizável fermentável. Não foram encontradas interações significativas nem diferenças entre as dietas para pH, concentração molar dos ácidos acético e butírico e proporção molar dos ácidos acético, propiônico e butírico e relação acético:propiônico. Os teores de amônia diferiram entre os potenciais de fermentação microbiana, 14,67 e 20,83 mg/100 mL para baixo e alto, respectivamente, e a concentração molar de ácido propiônico foi diferente entre os potenciais de ganho de peso, 7,62 e 8,94 mM, respectivamente, para baixo e alto ganho de peso. Não foram detectadas diferenças entre dietas para as degradabilidades das frações do feno de capim-marandu e da soja em grão. Houve diferença no parâmetro b e na degradabilidade efetiva a 5%/hora da proteína bruta para os potencias de GPC do milho em grão moído. Para o farelo de soja, ocorreu interação significativa entre os potencias de GPC e de fermentação microbiana para alguns dos parâmetros da MS e PB, o mesmo observado para o farelo de algodão. As diferenças encontradas não justificaram o balanceamento dos concentrados para os diferentes potenciais de produção avaliados.

Vitrification with DAP 213 and Cryotop of Ex Situ and In Situ Feline Cumulus-Oocyte Complexes

This study was undertaken to compare cryotolerance, in terms of viability and resumption of meiosis after warming and culture (24 and 48 h), of ex situ (isolated) and in situ (enclosed in the ovarian tissue) feline cumulusoocyte complexes (COCs) vitrified with DAP 213 (2 M DMSO, 1 M acetamide, 3 M propylene glycol) in cryotubes or Cryotop method. Ovaries were harvested from 49 pubertal queens. of each pair of ovaries, one was dissected to release COCs randomly divided into three groups: fresh COCs (control), ex situ COCs vitrified with DAP 213 and Cryotop. The cortex of the other ovary was sectioned into small fragments (approximately 1.5 mm3) and randomly assigned to be vitrified by DAP 213 or Cryotop. After warming, ex situ and in situ (retrieved form vitrified ovarian tissue) COCs were matured in vitro. Viability of oocytes was highly preserved after warming and culture in all treatments. Proportions of oocytes surrounded by complete layers of viable cumulus cells were remarkably decreased (p < 0.00001) in both vitrification procedures compared to fresh oocytes. Resumption of meiosis occurred in all treatments. After 24 h of culture, results were similar in ex situ and in situ vitrified oocytes regardless of the vitrification protocol used (range 29-40%), albeit lower (p < 0.05) than those of fresh oocytes (65.8%). After 48 h of culture, ex situ oocytes vitrified with Cryotop achieved the rates of meiosis resumption similar to fresh oocytes (53.8% vs 67.5%; p > 0.05) and ex situ and in situ oocytes vitrified with DAP 213 showed similar rates of resumption of meiosis. These findings demonstrated that DAP 213 and Cryotop preserve the viability of ex situ and in situ oocytes, but cumulus cells are highly susceptible to vitrification. However, the capability to resume meiosis evidences that feline immature oocytes vitrified as isolated or enclosed in the ovarian cortex have comparable cryotolerance.

Efeito de Diferentes Volumosos sobre a Degradabilidade in situ de Nutrientes e Variáveis da Fermentação Ruminal, Mediante a Aplicação da Somatotropina Bovina

The objective of this work was to evaluate the effect of diets with different forages (sugarcane, corn silage, hydrolyzed bagasse and sugarcane + corn silage) on the ruminal Fermentation and ruminal nutrients degradability, by the application of bovine somatotropin. Three bovines with ruminal cannulas were used in a factorial scheme (4 x 2). The pH, number of protozoa, ammonia and volatile fatty acids concentration were quantified. The potential and the effective degradability and degradation rate of dry matter and crude protein in each diet were evaluated, beyond gross energy disappearance. There were differences among diets on the effective degradability of dry matter and potential degradability, effective degradability and potentially degradable fraction of crude protein, being verified the same for the rBST application. There was effect of different forages on the variables of ruminal Fermentation. The treatments did not affect the gross energy disappearance. The rBST application did not affect the variables of ruminal fermentation.

In vitro and in situ activity of carboxymethyl cellulase and glutamate dehydrogenase according to supplementation with different nitrogenous compounds

Two experiments were carried out to evaluate the effect of supplementation with different nitrogenous compounds on the activities of carboxymethil cellulase (CMCase) and glutamate dehydrogenase (GDH). In the first experiment, four treatments were evaluated in vitro: cellulose, cellulose with casein, cellulose with urea, and cellulose with casamino acids. After 6, 12 and 24 hours of incubation, CMCase and GDH activity, pH, and concentrations of ammonia nitrogen (AN) and microbial protein were measured. In the three incubation periods, the concentration of AN was higher when urea was used as a supplemental source of nitrogen. The activity of CMCase was higher with the addition of urea and casamino acids when compared with the control and the casein treatment. Supplementation with casamino acids provided higher GDH activity when compared with the control at 6 hours of incubation. At 12 hours of incubation, the GHD activity was also stimulated by casein. At 24 hours, there was no difference in GHD activity among treatments. In the second experiment, three rumen-fistulated bulls were used for in situ evaluation. Animals were fed Tifton hay (Cynodon sp.) ad libitum. The treatments consisted of control (no supplementation), supplementation with non-protein nitrogenous compounds (urea and ammonium sulphate, 9:1) and supplementation with protein (albumin). In treatments with nitrogenous compound supplementation, 1 g of crude protein/kg of body weight was supplied. The experiment was conducted in a 3 × 3 Latin square design. The measurements were performed at 6, 12 and 24 hours after supplementation. No difference in GDH activity was observed among treatments. The control treatment showed higher CMCase activity when compared with the treatments containing supplemental sources of nitrogen. However, urea supplementation provided higher CMCase activity compared to albumin.

Teores de proteína bruta para bovinos alimentados com feno de capim-tifton 85: parâmetros ruminais, eficiência de síntese microbiana e degradabilidade in situ

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)