In vitro analysis of human tooth pulp chamber temperature after low-intensity laser therapy at different power outputs

In vitro studies have provided conflicting evidence of temperature changes in the tooth pulp chamber after low-level laser irradiation of the tooth surface. The present study was an in vitro evaluation of temperature increases in the human tooth pulp chamber after diode laser irradiation (GaAlAs, lambda = 808 nm) using different power densities. Twelve human teeth (three incisors, three canines, three premolars and three molars) were sectioned in the cervical third of the root and enlarged for the introduction of a thermocouple into the pulp chamber. The teeth were irradiated with 417 mW, 207 mW and 78 mW power outputs for 30 s on the vestibular surface approximately 2 mm from the cervical line of the crown. The highest average increase in temperature (5.6A degrees C) was observed in incisors irradiated with 417 mW. None of the teeth (incisors, canines, premolars or molars) irradiated with 207 mW showed temperature increases higher than 5.5A degrees C that could potentially be harmful to pulp tissue. Teeth irradiated with 78 mW showed lower temperature increases. The study showed that diode laser irradiation with a wavelength of 808 nm at 417 mW power output increased the pulp chamber temperature of certain groups of teeth, especially incisors and premolars, to critical threshold values for the dental pulp (5.5A degrees C). Thus, this study serves as a warning to clinicians that ""more"" is not necessarily ""better"".

Effect of power densities and irradiation times on the degree of conversion and temperature increase of a microhybrid dental composite resin

The different parameters used for the photoactivation process provide changes in the degree of conversion (DC%) and temperature rise (TR) of the composite resins. Thus, the purpose of this study was to evaluate the DC (%) and TR of the microhybrid composite resin photoactivated by a new generation LED. For the KBr pellet technique, the composite resin was placed into a metallic mould (1-mm thickness and 4-mm diameter) and photoactivated as follows: continuous LED LCU with different power density values (50-1000 mW/cm(2)). The measurements for the DC (%) were made in a FTIR Spectrometer Bomen (model MB-102, Quebec-Canada). The spectroscopy (FTIR) spectra for both uncured and cured samples were analyzed using an accessory for the diffuse reflectance. The measurements were recorded in the absorbance operating under the following conditions: 32 scans, 4-cm(-1) resolution, and a 300 to 4000-cm(-1) wavelength. The percentage of unreacted carbon-carbon double bonds (% C=C) was determined from the ratio of the absorbance intensities of aliphatic C=C (peak at 1638 cm(-1)) against an internal standard before and after the curing of the specimen: aromatic C-C (peak at 1608 cm-1). For the TR, the samples were made in a metallic mould (2-mm thickness and 4-mm diameter) and photoactivated during 5, 10, and 20 s. The thermocouple was attached to the multimeter to allow the temperature readings. The DC (%) and TR were calculated by the standard technique and submitted to ANOVA and Tukey`s test (p < 0.05). The degree of conversion values varied from 35.0 (+/- 1.3) to 45.0 (+/- 2.4) for 5 s, 45.0 (+/- 1.3) to 55.0 (+/- 2.4) for 10 s, and 47.0 (+/- 1.3) to 52.0 (+/- 2.4) for 20 s. For the TR, the values ranged from 0.3 (+/- 0.01) to 5.4 (+/- 0.11)degrees C for 5 s, from 0.5 (+/- 0.02) to 9.3 (+/- 0.28)degrees C for 10 s, and from 1.0 (+/- 0.06) to 15.0 (+/- 0.95)degrees C for 20 s. The power densities and irradiation times showed a significant effect on the degree of conversion and temperature rise.

Absorption of primary macronutrients and soybean growth at different compactation densities and moisture levels in a silt loam soil

ABSTRACT Soybean cultivation is increasing rapidly in the region of Alto Vale do Itajaí, State of Santa Catarina, where there is a predominance of silt soils. The objective of this work was to evaluate the content of primary macronutrients in shoots and shoot and root vegetative growth of soybean (Glicine max L. Merrill) grown in a silt-loam soil under different compactation densities and moisture levels. A randomized block design in a 4x4 factorial arrangement was used, with four compactation densities: 1.00; 1.20; 1.40 and 1.60 Mg m-3, and four soil moisture levels: 0.130; 0.160; 0.190 and 0.220 kg kg-1 and four replications. Each pot consisted of the overlapping of three 150-mm PVC rings, where soil was maintained in the higher and lower part of the pot with a density of 1.00 Mg m-3 and in the intermediate ring, the compactation densities were increased. Values of soil density higher than 120 Mg m-3 negatively affected N, P and K uptake by soybean plants, as well as the plant mass of the shoots and roots. The higher levels of soil moisture reduced the compaction effect and promoted better absorption of P and K.

The impact of different power dividers used in a non-uniform planar antenna array

Wireless communications are widely used for various applications, requiring antennas with different features. Often, to achieve the desired radiation pattern, is necessary to employ antenna arrays, using non-uniform excitation on its elements. Power dividers can be used and the best known are the T-junction and the Wilkinson power divider, whose main advantage is the isolation between output ports. In this paper the impact of this isolation on the overall performance of a circularly polarized planar antenna array using non-uniform excitation is investigated. Results show a huge decrease of the array bandwidths either in terms of return loss or in polarization, without resistors. © 2014 IEEE.

Nutrient relations during an eucalyptus cycle at different population densities

To synchronize nutrient availability with the requirements of eucalyptus during a cultivation cycle, the nutrient flow of this system must be well understood. Essential, for example, is information about nutrient dynamics in eucalyptus plantations throughout a cultivation cycle, as well as impacts on soil nutrient reserves caused by the accumulation and subsequent export of nutrients via biomass. It is also important to quantify the effect of some management practices, such as tree population density (PD) on these fluxes. Some nutrient relations in an experiment with Eucalyptus grandis, grown at different PDs in Santa Barbara, state of Minas Gerais, Brazil, were evaluated for one cultivation cycle. At forest ages of 0.25, 2.5, 4.5, and 6.75 years, evaluations were carried out in the stands at seven different PDs (between 500 and 5,000 trees ha-1) which consisted in chemical analyses of plant tissue sampled from components of the aboveground parts of the tree, from the forest floor and the litterfall. Nutrient contents and allocations of the different biomass components were estimated. In general, there were only small and statistically insignificant effects of PD on the nutrient concentration in trees. With increasing forest age, P, K, Ca and Mg concentrations were reduced in the aboveground components and the forest floor. The magnitud of biochemical nutrient cycling followed the sequence: P > K > N > Mg. At the end of the cycle, the quantities of N, P, Ca and Mg immobilized in the forest floor were higher than in the other components.

Growth and stress of dourado cultivated in cages at different stocking densities

The objective of this work was to evaluate the growth and the stress levels of juvenile dourado (Salminus brasiliensis) cultivated in cages. Fish stocked at densities of 15 (D15) and 30 (D30) fish per square meter were evaluated in a completely randomized design with three replicates. Fish were fed twice a day with extruded ration (42% crude protein). Density influenced only biomass and daily food intake, and glucose and lactate concentrations increased over time. D15 and D30 did not influence the growth of dourado. However, the increase of glucose and lactate levels over time indicates that cultivation in cages is a stressful condition for this species.

Weeds infestation in corn intercropped with forages at different planting densities

Corn is planted in the Center West region of Brazil as a second crop, following soybeans or beans. Intercropping of Brachiaria species with corn as a second crop increases the mulching in the cropping system. This study aimed to evaluate the weeds infestation in soybeans following corn/forages intercrop, as a function of corn plant structure, forage species and density. Experiments were conducted in a completely randomized blocks design with four replications, in Ponta Porã and Dourados municipalities, Mato Grosso do Sul state, Brazil, in 2010/2011. Treatments consisted of three corn hybrids with distinct plant architectures intercropped with three forage species: Brachiaria ruziziensis, B. brizantha and B.decumbens, at five densities, and the resulting dry mass was maintained throughout the winter. During the following cropping season, forages were desiccated prior to planting soybeans, and the dry mass of weeds, dry mass of the mulching, soil coverage by weeds, and the broadleaf/grass weed species index (WPI) were determined 15 days after soybean emergence, submitted to an F-test, and analyzed either by regression or by multiple mean comparison, according to the nature of the data. When intercropping corn with species of Brachiaria, a reduction in the overall weeds infestation may always be expected; among the studied forage species, more problems with weeds may be anticipated in areas with a less competitive species, e.g. B.ruziziensis. Under the conditions of the trials, B.brizantha and B.decumbens were more capable of inhibiting the emergence of weed species in the winter.

Weeds under the canopies of tree species submitted to different planting densities and intercropping

Assessing the growth and floristic composition of species that grow under the canopy of trees is important for weed control (WC). The objective of this study was to assess two experiments (E1 and E2), when the trees were two years and one year of age, respectively. In E1, sabiá (S) and gliricidia (G) were submitted to planting densities from 400 to 1.200 plants ha-1. In E2, growing systems consisting of S, G, and neem (N) combinations were compared: SSS, GGG, NNN, GSG, NSN, SGS, NGN, SNS, and GNG (each letter represents a row of plants). A random block design was adopted, with three (E1) and four (E2) replicates. In E1, treatments were arranged as split-plots (species in plots). In E2, the degrees of freedom for treatments (8) were partitioned into growing systems (treatments that involved the same species) and between growing system groups (2). Twenty-one weed species were found in E1. Gliricidia attained greater plant height than sabiá, but these species did not differ in canopy diameter, number of weed species per plot, and weed green and dry biomass of the shoot. Higher planting densities resulted in the reduction of all those traits. Twenty-six weed species were found in E2. Growing systems that included gliricidia showed canopies with greater diameters than growing systems that included neem. There were no differences between growing systems for number of weed species per plot and for weed green and dry biomass of the shoot.

Anatomy and physiology of Cattail as related to different population densities

The objective of this work was to evaluate the effects of the population density of Typha angustifolia plants in the anatomical and physiological characteristics. Plants were collected from populations of high density (over 50% of colonization capacity) and low density (less than 50% of colonization capacity) and cultivated under controlled greenhouse conditions. Plants from both populations were grown in plastic trays containing 4 L of nutritive solution for 60 days. At the end of this period, the relative growth rate, leaf area ratio, net assimilatory rate, root/shoot ratio, leaf anatomy, root anatomy, and catalase and ascorbate peroxidase activities were evaluated. Plants from high density populations showed increased growth rate and root/shoot ratio. Low density populations showed higher values of stomatal index and density in leaves, as well as increased palisade parenchyma thickness. Root epidermis and exodermis thickness as well as the aerenchyma proportion of high density populations were reduced, these plants also showed increased vascular cylinder proportion. Only catalase activity was modified between the high and low density populations, showing increased values in low density populations. Therefore, different Typha angustifolia plants show differences in its anatomy and physiology related to its origins on high and low density conditions. High density population plants shows increased growth capacity related to lower apoplastic barriers in root and this may be related to increased nutrient uptake capacity.

Changes in canola plant architecture and seed physiological quality in response to different sowing densities

The aim of this study was to evaluate changes in canola yield components and seed physiological quality in response to different sowing densities. The study was made in a greenhouse at the REIPESOL Company Technological Center, Madrid - Spain, with the commercial "Toccata" hybrid variety. The initial sowing density was 360,000 plants/ha and the plant population was later thinned down to include treatments of 250 and 180 thousand plants/ha. Harvested seeds were sent to the Seed Technology Center Laboratory (CATES) at the Madrid Polytechnic University (UPM) to evaluate changes in plant architecture and yield components, as well as the seed physiological quality of different plant parts. Results demonstrated that canola plants showed changes in morphology and yield components in response to different sowing densities. The population of 250,000 plants/ha showed the best seed yield demonstrating that maximum yield is directly related to a correct sowing density. The number of pods/plant was the most important component for increased seed yield/plant and seed yield/area. The spatial distribution of canola seeds in the plant and canola sowing density did not affect seed physiological quality.

Quality of Cotesia flavipes (Hymenoptera: Braconidae) reared at different host densities and the estimated cost of its commercial production

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Stress responses of juvenile matrinxã (Brycon amazonicus) after transport in a closed system under different loading densities

Neste estudo, foram investigadas as densidades de carga adequadas para transporte de matrinxãs juvenis em sistema fechado com sacos plásticos. O transporte de 4h foi feito com peixes (23,5±0,4g; 11,6 (0,08cm) em jejum por 24h, em densidades de 83g L-1 (D1), 125g L-1 (D2), 168g L-1 (D3) e 206g L-1 (D4). Os peixes foram amostrados antes do transporte (AT), logo após o transporte (chegada) (DT) e 24h depois. A qualidade da água foi monitorada antes da captura dos peixes nos tanques de depuração, após o transporte nos sacos plásticos e nos tanques de recuperação. O oxigênio da água diminuiu para valores inferiores a 4mg L-1 em D2, D3 e D4, a temperatura esteve em torno de 32°C, pH 6,5-6,78, a amônia total foi de 1,09-1,7mg L-1, a amônia não-ionizada foi de 3,58-9,33 x 10³mg L-1 e alcalinidade 134-165mg CaCO3 L-1. O cortisol plasmático e a glicose sanguínea aumentaram após o transporte nos peixes em todas as densidades ensaiadas, voltando aos valores controle 24h depois. Os valores de osmolaridade não mudaram logo após o transporte, mas aumentaram 24h depois de modo igual em todas as densidades. O cloreto plasmático diminuiu na chegada, de modo inversamente proporcional à densidade de carga. O hematócrito diminuiu 24h depois da chegada dos peixes, em todas as densidades testadas, mas não houve diferença no número de eritrócitos. Não houve mortalidade até uma semana após o transporte. O matrinxã mostrou ser uma espécie tolerante a altas densidades de carga em embalagens para transporte além de suportar baixos níveis de oxigênio na água.

Yield performance and leaf nutrient levels of coffee cultivars under different plant densities

Cultivares de cafeeiro (Coffea Arabica L.) adaptadas às regiões de cultivo, com população de plantas otimizada e adequado estado nutricional são premissas para a obtenção de produções elevadas de café. Estudou-se a produção trienal de café e o teor foliar de macronutrientes de cultivares de cafeeiro em função das densidades de plantio. Foram utilizados os cultivares Catuaí Amarelo (IAC 47), Obatã (IAC 1669-20), Acaiá (IAC 474-19) e Icatu Amarelo (IAC 2944) nas populações de 2.500 plantas ha-1 com duas plantas por cova; e, 5.000, 7.519 e 10.000 plantas ha-1 com uma planta por cova. As plantas foram adubadas de modo homogêneo, porém, sem calagem. À medida que a população de cafeeiros aumentou, a produtividade trienal de café aumentou, a produção de frutos por planta diminuiu e os teores foliares de fósforo (P), potássio (K) e enxofre (S) aumentaram. Nos cafeeiros sob adensamento encontrou-se igual ou maior teor de macronutrientes do que naqueles sob espaçamento convencional, sendo que os maiores teores foram observados nas cultivares de porte alto, e os menores, na cultivar Obatã, de porte baixo. Nos cafeeiros das covas com uma planta observou-se maior produção de café e menores concentrações de P, Ca e S do que naqueles das covas com duas plantas. No geral, os cultivares e as populações de cafeeiros estavam com teores de N e S acima dos limites de referência citados na literatura, mas com teores dos demais macronutrientes dentro da faixa adequada.

Three- phase four-wire circuits interpretation by means of different power theories

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)