Preliminary studies on the effects of d-limonene to workers of the leaf-cutting ant Atta sexdens rubropilosa and its implications for control

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desempenho de cultivares de alface crespa em dois ambientes de cultivo em sistema hidropônico

Este trabalho foi desenvolvido em Ribeirão Preto-SP, de 06/02 a 07/04 de 2006. O objetivo foi avaliar o desempenho de cinco cultivares de alface (Pira Roxa, Belíssima, Locarno, Crespona Gigante e Verônica) em dois ambientes de cultivo (casa de vegetação climatizada e não climatizada) em sistema hidropônico NFT. O delineamento experimental foi em blocos casualizados para cada ambiente com três repetições sendo cinco cultivares. Os ambientes foram comparados por meio de análise conjunta. Avaliaram-se a massa fresca e seca da parte aérea, massas fresca e seca do caule, massa fresca e seca da raiz, número de folhas maiores que 10 cm e número total de folhas. Não houve efeito significativo da interação cultivares e ambientes, demonstrando que as cultivares tiveram comportamento similar em ambos os ambientes.

Biology and fertility life table of the South American fruit fly Anastrepha fraterculus on grape

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação da queima e da adição de milho desintegrado com palha e sabugo na ensilagem de cana-de-açúcar

Neste trabalho, avaliou-se a fermentação da cana-de-açúcar queimada, ensilada com ou sem uso de aditivo seco. Os tratamentos (seis no total) consistiram da silagem de cana crua ou queimada, adicionada de 0, 50 ou 100 g/kg de milho desintegrado com palha e sabugo (MDPS), com base no peso verde da forragem. Foram determinados os teores de MS, PB, nitrogênio insolúvel em detergente ácido (NIDA), FDN, FDA, celulose, hemicelulose e lignina. Na avaliação das características fermentativas, foram determinados os valores de carboidratos solúveis, o poder tamponante, o pH e as concentrações de nitrogênio amoniacal e etanol. Como características microbiológicas, avaliou-se o desenvolvimento de leveduras. A inclusão de MDPS elevou os teores de MS e reduziu discretamente os teores de N-NH3 e etanol das silagens, não ocasionando efeito nos valores de pH e na população de leveduras. A presença do fogo reduziu a concentração de MS das silagens, elevou os teores de etanol e leveduras e diminuiu os teores de N-NH3. A fermentação etanólica durante a ensilagem não foi controlada com a inclusão de aditivo seco ou com o uso do fogo.

Reguladores de crescimento vegetal na concentração de macronutrientes em videira Itália

Em clima tropical semi-árido, o uso de reguladores vegetais em fruteiras permite o manejo do crescimento vegetativo, tão necessário ao escalonamento da produção e ao aumento da fertilidade das gemas. Estas substâncias influenciam vários fenômenos fisiológicos relacionados com a absorção mineral, como a condutância de membrana e utilização metabólica de íons. O objetivo deste trabalho foi avaliar o crescimento vegetativo, produção de matéria seca dos ramos, concentração e quantidade acumulada de N, P, K, Ca e Mg nos ramos e nos pecíolos e produção de panículas florais em resposta ao uso de reguladores vegetais, em plantas de videira da cultivar Itália. No experimento foram avaliados três ciclos vegetativos e cinco tratamentos (controle, chlormequat - 1500 mg L-1; daminozide - 3000 mg L-1; uniconazole - 30 mg L-1 e cloreto de mepiquat - 300 mg L-1), aplicados nas plantas em pulverizações aos 35 e 70 dias após a poda. Com o chlormequat e o uniconazole ocorreu efeito cumulativo nas plantas, quando aplicados em ciclos sucessivos da cultura, favorecendo o acúmulo de nutrientes e a diferenciação de gemas férteis em comparação com as plantas controle das videiras 'Itália'. Embora o daminozide tenha inibido significativamente o crescimento das plantas, não resultou em maior acúmulo de nutrientes e emissão de panículas florais nas plantas tratadas.

Latex use as an occlusive membrane for guided bone regeneration

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

Conventional and microwave sintering of CaCu(3)Ti(4)O(12)/CaTiO(3) ceramic composites: non-ohmic and dielectric properties

The non-ohmic and dielectric properties as well as the dependence on the microstructural features of CaCu(3)Ti(4)O(12)/CaTiO(3) ceramic composites obtained by conventional and microwave sintering were investigated. It was demonstrated that the non-ohmic and dielectric properties depend strongly on the sintering conditions. It was found that the non-linear coefficient reaches values of 65 for microwave-sintered samples and 42 for samples sintered in a conventional furnace when a current density interval of 1-10 mA cm(-2) is considered. The non-linear coefficient value of 65 is equivalent to 1500 for samples sintered in the microwave if a current interval of 5-30 mA is considered as is shortly discussed by Chung et al (2004 Nature Mater. 3 774). Due to a high non-linear coefficient and a low leakage current (90 mu A) under both processing conditions, these samples are promising for varistor applications. The conventionally sintered samples exhibit a higher relative dielectric constant at 1 kHz (2960) compared with the samples sintered in the microwave furnace (2100). At high frequencies, the dielectric constant is also larger in the samples sintered in the conventional furnace. Depending on the application, one or another synthesis methodology is recommended, that is, for varistor applications sintered in a microwave furnace and for dielectric application sintered in a conventional furnace.

Modeling and Experimental Aspects of Self-healing Bolted Joint through Shape Memory Alloy Actuators

Bolted joints are a form of mechanical coupling largely used in machinery due to their reliability and low cost. Failure of bolted joints can lead to catastrophic events, such as leaking, train derailments, aircraft crashes, etc. Most of these failures occur due to the reduction of the pre-load, induced by mechanical vibration or human errors in the assembly or maintenance process. This article investigates the application of shape memory alloy (SMA) washers as an actuator to increase the pre-load on loosened bolted joints. The application of SMA washer follows a structural health monitoring procedure to identify a damage (reduction in pre-load) occurrence. In this article, a thermo-mechanical model is presented to predict the final pre-load achieved using this kind of actuator, based on the heat input and SMA washer dimension. This model extends and improves on the previous model of Ghorashi and Inman [2004, "Shape Memory Alloy in Tension and Compression and its Application as Clamping Force Actuator in a Bolted Joint: Part 2 - Modeling," J. Intell. Mater. Syst. Struct., 15:589-600], by eliminating the pre-load term related to nut turning making the system more practical. This complete model is a powerful but complex tool to be used by designers. A novel modeling approach for self-healing bolted joints based on curve fitting of experimental data is presented. The article concludes with an experimental application that leads to a change in joint assembly to increase the system reliability, by removing the ceramic washer component. Further research topics are also suggested.

Bone healing in critical-size defects treated with new bioactive glass/calcium sulfate: A histologic and histometric study in rat calvaria

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Long-term effect of carbodiimide on dentin matrix and resin-dentin bonds

Objectives: To characterize the interaction of 1-Ethyl-3-[3-dimethylaminopropyl] carbodiimide Hydrochloride (EDC) with dentin matrix and its effect on the resin-dentin bond. Methods: Changes to the stiffness of demineralized dentin fragments treated with EDC/N-hydroxysuccinimide (NHS) in different solutions were evaluated at different time points. The resistance against enzymatic degradation was indirectly evaluated by ultimate tensile strength (UTS) test of demineralized dentin treated or not with EDC/NHS and subjected to collagenase digestion. Short- and long-term evaluations of the strength of resin-dentin interfaces treated with EDC/NHS for 1 h were performed using microtensile bond strength (mu TBS) test. All data (MPa) were individually analyzed using ANOVA and Tukey HSD tests (alpha = 0.05). Results: The different exposure times significantly increased the stiffness of dentin (p < 0.0001, control-5.15 and EDC/NHS-29.50), while no differences were observed among the different solutions of EDC/NHS (p = 0.063). Collagenase challenge did not affect the UTS values of EDC/NHS group (6.08) (p > 0.05), while complete degradation was observed for the control group (p = 0.0008, control-20.84 and EDC/NHS-43.15). EDC/NHS treatment did not significantly increase resin-dentin mu TBS, but the values remained stable after 12 months water storage (p < 0.05). Conclusions: Biomimetic use of EDC/NHS to induce exogenous collagen cross-links resulted in increased mechanical properties and stability of dentin matrix and dentin-resin interfaces. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 94B: 250-255, 2010.

Cytotoxic Effects of Different Concentrations of a Carbamide Peroxide Bleaching Gel on Odontoblast-Like Cells MDPC-23

This study evaluated the cytotoxic effects of a carbamide peroxide (CP) bleaching gel at different concentrations on odontoblast-like cells. Immortalized cells of the MDPC-23 cell line (30,000 cells/cm(2)) were incubated for 48 h. The bleaching gel was diluted in DMEM culture medium originating extracts with different CP concentrations. The amount (mu g/mL) of hydrogen peroxide (H(2)O(2)) released from each extract was measured by the leukocrystal violet/horseradish peroxidase enzyme assay. Five groups (n = 10) were formed according to the CP concentration in the extracts: G1-DMEM (control); G2-0.0001 % CP (0.025 mu g/mL H(2)O(2)); G3-0.001% CP (0.43 mu g/mL H(2)O(2)); G4-0.01% CP (2.21 mu g/mL H(2)O(2)); and G5-0.1 % CP (29.74 mu g/mL H(2)O(2)). MDPC-23 cells were exposed to the bleaching gel extracts for 60 min and cell metabolism was evaluated by the NITT assay. Data were analyzed statistically by one-way ANOVA and Tukey's test (alpha = 0.05). Cell morphology was examined by scanning electron microscopy. The percentages of viable cells were as follows: G1, 100%; G2, 89.41%; G3, 82.4%; G4, 61.5%; and G5, 23.0%. G2 and G3 did not differ significantly (p > 0.05) from G1. The most severe cytotoxic effects were observed in G3 and G4. In conclusion, even at low concentrations, the CP gel extracts presented cytotoxic effects. This cytotoxicity was dose-dependent, and the 0.1% CP concentration caused the most intense cytopathic effects to the MDPC-23 cells. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 9013: 907-912, 2009

Transdentinal cytotoxic effects of different concentrations of chlorhexidine gel applied on acid-conditioned dentin substrate

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Titanium surfaces with nanotopography modulate cytokine production in cultured human gingival fibroblasts

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Histological evaluation of chitosan-based biomaterials used for the correction of critical size defects in rat's calvaria

Chitosan, a biopolymer obtained from chitin, and its derivates, such as chitosan hydrochloride, has been reported as wound healing accelerators and as possible bone substitutes for tissue engineering, and therefore these Substances could be relevant in dentistry and periodontology. The purpose of this investigation was to make a histological evaluation of chitosan and chitosan hydrochloride biomaterials (gels) used in the correction of critical size bone defects made in rat's calvaria. Bone defects of 8 mm in diameter were surgically created in the calviria of 50 Holtzman (Rattus norvegicus) rats and filled with blood clot (control), low molecular weight chitosan, high molecular weight chitosan, low molecular weight chitosan hydrochloride, and high molecular weight chitosan hydrochloride, numbering 10 animals, divided into two experimental periods (15 and 60 days), for each biomaterial. The histological evaluation was made based on the morphology of the new-formed tissues in defect's region, and the results indicated that there was no statistical difference between the groups when the new bone formation in the entire defect's area were compared (p > 0.05) and, except in the control groups, assorted degrees of inflammation Could be Seen. In Conclusion, chitosan and chitosan hydrochloride biomaterials used in this study were not able to promote new bone formation in critical size defects made in rat's calvaria. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res 93A: 107-114, 2016

Argon-based atmospheric pressure plasma enhances early bone response to rough titanium surfaces

This study investigated the effect of an Argon-based atmospheric pressure plasma (APP) surface treatment operated chairside at atmospheric pressure conditions applied immediately prior to dental implant placement in a canine model. Surfaces investigated comprised: rough titanium surface (Ti) and rough titanium surface + Argon-based APP (Ti-Plasma). Surface energy was characterized by the Owens-Wendt-Rabel-Kaelble method and chemistry by X-ray photoelectron spectroscopy (XPS). Six adult beagles dogs received two plateau-root form implants (n = 1 each surface) in each radii, providing implants that remained 1 and 3 weeks in vivo. Histometric parameters assessed were bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Statistical analysis was performed by Kruskall-Wallis (95% level of significance) and Dunn's post-hoc test. The XPS analysis showed peaks of Ti, C, and O for the Ti and Ti- Plasma surfaces. Both surfaces presented carbon primarily as hydrocarbon (C?C, C?H) with lower levels of oxidized carbon forms. The Ti-Plasma presented large increase in the Ti (+11%) and O (+16%) elements for the Ti- Plasma group along with a decrease of 23% in surface-adsorbed C content. At 1 week no difference was found in histometric parameters between groups. At 3 weeks significantly higher BIC (>300%) and mean BAFO (>30%) were observed for Ti-Plasma treated surfaces. From a morphologic standpoint, improved interaction between connective tissue was observed at 1 week, likely leading to more uniform and higher bone formation at 3 weeks for the Ti-Plasma treated implants was observed. (C) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 2012.