Morfo-anatomia do eixo vegetativo aéreo de Achyrocline alata (Kunth) DC. (Asteraceae)

Achyrocline alata occurs in a dense and low vegetation in Mato Grosso do Sul State, Brazil and it has been studied under physical-chemical and yield aspects, being scarce anatomical data. The present work has as objective the study of the aerial vegetative axis. Stem is cylindrical and hairy, having five wings, which are arisen from their leaves. The blade shows the presence of uniseriate epidermis, which is covered by the cuticle of variable thickness; and non-glandular and glandular trichomes. The non-glandular trichomes are uniseriate and multicellular and have their apex cell in whip form, while the glandular trichomes are multicellular, uniseriate or biseriate. The mesophyll is dorsiventral with uni-stratified palisade parenchyma in most of the cases and lacunal parenchyma formed by three to four layers of irregular cells. Only one collateral vascular bundle occurs in the midvein. Stem in transversal section is covered by epidermis with trichomes similar to leaves; the cortex is constituted by a discontinuous area of angular collenchyma, which is followed by chlorophyll parenchyma. Vascular cylinder that is delimited by pericycle shows vascular bundles of collateral type. In the secondary structure, the periderm is originated from epidermal and subepidermal tissues. In vascular region, the fascicular cambium differs into secondary xylem and phloem, while interfascicular cambium produces sclerenchymatous tissue.

One-dimensional superfluid Bose-Fermi mixture: Mixing, demixing, and bright solitons

We study an ultracold and dilute superfluid Bose-Fermi mixture confined in a strictly one-dimensional (1D) atomic waveguide by using a set of coupled nonlinear mean-field equations obtained from the Lieb-Liniger energy density for bosons and the Gaudin-Yang energy density for fermions. We consider a finite Bose-Fermi interatomic strength gbf and both periodic and open boundary conditions. We find that with periodic boundary conditions-i.e., in a quasi-1D ring-a uniform Bose-Fermi mixture is stable only with a large fermionic density. We predict that at small fermionic densities the ground state of the system displays demixing if gbf >0 and may become a localized Bose-Fermi bright soliton for gbf <0. Finally, we show, using variational and numerical solutions of the mean-field equations, that with open boundary conditions-i.e., in a quasi-1D cylinder-the Bose-Fermi bright soliton is the unique ground state of the system with a finite number of particles, which could exhibit a partial mixing-demixing transition. In this case the bright solitons are demonstrated to be dynamically stable. The experimental realization of these Bose-Fermi bright solitons seems possible with present setups. © 2007 The American Physical Society.

Fatigue resistance of bovine teeth restored with resin-bonded fiber posts: Effect of post surface conditioning

This study evaluated the effect of post surface conditioning on the fatigue resistance of bovine teeth restored with resin-bonded fiber-reinforced composite (FRC). Root canals of 20 single-rooted bovine teeth (16 mm long) were prepared to 12 mm using a preparation drill of a double-tapered fiber post system. Using acrylic resin, each specimen was embedded (up to 3.0 mm from the cervical part of the specimen) in a PVC cylinder and allocated into one of two groups (n = 10) based on the post surface conditioning method: acid etching plus silanization or tribochemical silica coating (30 μm SiOx + silanization). The root canal dentin was etched (H2PO3 for 30 seconds), rinsed, and dried. A multi-step adhesive system was applied to the root dentin and the fiber posts were cemented with resin cement. The specimens were submitted to one million fatigue cycles. After fatigue testing, a score was given based on the number of fatigue cycles until fracture. All of the specimens were resistant to fatigue. No fracture of the root or the post and no loss of retention of the post were observed. The methodology and the results of this study indicate that tribochemical silica coating and acid etching performed equally well when dynamic mechanical loading was used.

Verificação da atividade antibacteriana de sabonete líquido contendo extrato glicólico de Dimorphandra mollis Benth.

Dimorphandra mollis Benth., Compositae, false barbatimão, has been used topically as a healing, astringent and antibacterial. In this study, antibacterial activity was verified on liquid soap containing glycolic extract of D. mollis (DGE) at different concentrations (8, 15 and 20%) and at different pH levels (6 and 8). Five soap formulations (F) were prepared: F1 - tryclosan (0.1%), F2 - DGE (8%), F3 - DGE (15%), F4 - DGE (20%) and F5 - without preservatives. Bark of D. mollis were dried in a circulating air oven and ground. The rude extracts were prepared by turbo extraction with ethanol. After screening, the extract were concentrated in rotating evaporator, lyophilized and resuspended in propileneglycol to obtain the glycolic extract. The antimicrobial activity was verified by diffusion in agar method, using cylinder in plate. Plates containing Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli were incubated at 37°C for 24 hours. After incubation, the results were analysed with a pachymeter, observing the bacterial grouth inhibition halo diameter. It was verified that the liquid soap containing tryclosan caused on inhibition of bacterial growth at both pH levels; the soaps without preservatives and containing DGE, independently of the concentration and pH levels used, did not present antibacterial activity.

Analysis of polymerization time on abrasive wear of dental resins

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

Cementation of fiber post: influence of the cement insertion techniques on the bond strength of the fiber post-root dentin and the quality of the cement layer.

The aim of this study was to assess the influence of resin cement insertion methods on the bond strength of a fiber post to root dentin and quality of the cement layer. Forty bovine single-roots (length =16 mm) were randomly allocated into four groups, according to the cement insertion methods (N.=10): Gr1- Lentulo drill #40, Gr2- Centrix syringe, Gr3- Explorer #5, Gr4- fiber post. The root canals were prepared at 12 mm, using preparation bur # 3 of a cylinder quartz-FRC post (Aesthet post-plus, Bisco). The fiber posts were cemented using a multi-step etch-and-rinse adhesive system (All Bond 2®, Bisco) and a dual-cured resin cement (Duolink, Bisco). Each root was cut into seven samples: four samples of 1.8 mm thickness for push-out testing, and three with 0.5 mm for cement layer quality analyzing. One-way ANOVA was used for the push-out test values and the One-Way Kruskal-Wallis (P<0.05) and Dunn (10%) tests for the cement layer analyzes. ANOVA showed that the cement layer quality was affected by the cement insertion methods (P=0.0044): Gr1 (3.8 ± 1.3a), Gr2 (3.2 ± 1.3a), Gr3 (5.2 ± 1.5a,b) and Gr4 (5.2 ± 1.5b) (Dunn test), whereas the bond strength (MPa) was not affected by cement insertion methods: G1 (4.2 ± 1.3), G2 (3.2 ± 1.8), G3 (4.5 ± 0.9), G4 (3.1 ± 1.3). The fiber posts should be cemented with the assistance of the lentulo drill or centrix syringe to promote the best cement layer results.

Adhesion between fiber post and root dentin: evaluation of post surface conditioning for bond strength improvement.

The aim of this paper was to evaluate two surface conditioning methods associated with the application of adhesive on the post surface for improving the bond to resin cement. Sixty single-rooted bovine teeth were sectioned at 16 mm in length, prepared (9 mm depth), embedded in a PVC cylinder using acrylic resin, and allocated into 3 groups (N.=20) according to post surface treatment: cleaning with ethanol (control group); etching with hydrogen peroxide; etching with hydrofluoric acid. Ten posts for each group were silanized and other 10 posts were silanized and received an adhesive agent. The posts were cemented with self-adhesive resin cement (RelyX U100 resin cement). All teeth were sectioned perpendicularly to the long axis (2 mm thickness per slice), submitted to push out bond strength testing and the type of failure was recorded. The obtained data were submitted to two-way ANOVA and Turkey's test, with the level of significance set at 5%. Neither the hydrofluoric acid or hydrogen peroxide post surface treatment, nor the adhesive application, had an influence on bond strength values. The main type of failure was adhesive between cement and dentin. Etching and the application of an adhesive on the post surface did not presented a significant influence on the bond strength results for the fiber post resin cement-root dentin assembly. The cement appears to adhere very well to the fiber post surface rather than the dentin surface.

Effect of axial loads on implant-supported partial fixed prostheses by strain gauge analysis

Objectives: The present study used strain gauge analysis to perform an in vitro evaluation of the effect of axial loading on 3 elements of implant-supported partial fixed prostheses, varying the type of prosthetic cylinder and the loading points. Material and methods: Three internal hexagon implants were linearly embedded in a polyurethane block. Microunit abutments were connected to the implants applying a torque of 20 Ncm, and prefabricated Co-Cr cylinders and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n = 5). Four strain gauges (SG) were bonded onto the surface of the block tangentially to the implants, SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments with a 10 Ncm torque and an axial load of 30 kg was applied at five predetermined points (A, B, C, D, E). The data obtained from the strain gauge analyses were analyzed statistically by RM ANOVA and Tukey's test, with a level of significance of p<0.05. Results: There was a significant difference for the loading point (p=0.0001), with point B generating the smallest microdeformation (239.49 με) and point D the highest (442.77 με). No significant difference was found for the cylinder type (p=0.748). Conclusions: It was concluded that the type of cylinder did not affect in the magnitude of microdeformation, but the axial loading location influenced this magnitude.

On nonlinear dynamics in a free fluid surface of a tank excited by a non-ideal power source

We investigate the nonlinear oscillations in a free surface of a fluid in a cylinder tank excited by non-ideal power source, an electric motor with limited power supply. We study the possibility of parametric resonance in this system, showing that the excitation mechanism can generate chaotic response. Additionally, the dynamics of parametrically excited surface waves in the tank can reveal new characteristics of the system. The fluid-dynamic system is modeled in such way as to obtain a nonlinear differential equation system. Numerical experiments are carried out to find the regions of chaotic solutions. Simulation results are presented as phase-portrait diagrams characterizing the resonant vibrations of free fluid surface and the existence of several types of regular and chaotic attractors. We also describe the energy transfer in the interaction process between the hydrodynamic system and the electric motor. Copyright © 2011 by ASME.

Antibacterial activity of gels with pomegranate, apricot and green tea glycolic extracts

Pomegranate (PGE) and green tea (GTGE) glycolic extracts are being employed in formulations because of their antiseptic and astringent effects. Apricot (AGE) glycolic extract possesses function cooling and antibacterial. The aim was to verify the antibacterial activity of these extracts incorporated in gel base. The antibacterial activity was verified by diffusion in agar method, using cylinder in plate. Plates containing Staphylococcus aureus (ATCC 6538p), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 10536) and Salmonella sp. (ATCC 19196) were incubated at 37°C for 24 hours. After incubation, the results were analysed with a pachymeter, observing the bacterial growth inhibition halo diameter and the statistical significance level was determined. PGE presented activity only against P. aeruginosa; GTGE presented activity against S. aureus, P. aeruginosa and E. coli; and AGE presented activity against P. aeruginosa and Salmonella sp. According to the experimental conditions, it is possible to conclude that GTGE presented the greater growth inhibition halo diameter when compared with other extracts, suggesting higher antibacterial action of this extract.

The use of CPT to evaluate the effect of helical pile installation in tropical soils

The uplift capacity of helical piles depends on the shear resistance of the soil above the helical plates. During helical pile installation, the soil traversed by the plates are sheared and displaced laterally, and consequently the soil structure is disturbed. Considering this fact, the aim of this paper is presenting the effect of helical piles installation in the soil mass by means of CPT tests carried out close to the soil cylinder above the pile helices. The CPT tests were performed at the CRHEA site from the Sao Carlos School of Engineering, Sao Carlos city, inland of Sao Paulo State, Brazil. In addition, an interpretation of CPT tests data for stratigrafic logging are presented and compared to Standard Penetration Tests (SPT) carried out at this site. This study showed that the CPT sleeve friction fs data were affected by the installation of helical pile in this particular tropical soil site. © 2013 Taylor & Francis Group.

Perdas qualitativas na colheita mecanizada de sementes de soja

The study aimed to assess the physical and physiological characteristics of soybean seeds collected in grain tank and the outlet of the discharge tube of the harvester, depending on the year and the forward speed of the harvester. The experimental design was completely randomized in a factorial 2 x 2 x 2 tested two harvesters of different years, two displacement's speeds and two locations of sample collection, totaling eight treatments with four replications. The harvest of soybean cv. COODETEC 217, was performed with two tangential harvesters, aged three and four years, with 900 rpm rotation of the cylinder, operating at forward speeds of 4 ± 0.5 km h-1 and 7 ± 0.5 km h-1. Seed samples (approximately 3 kg) were withdrawn at the grain tank and the outlet of the discharge tube of the harvester and subjected to determinations of water content in field and laboratory. Subsequently, we evaluated purity, mechanical damage, germination and seed vigor. The younger harvester had a higher percentage of pure seed and lowest percentage of inert material. The increase in forward speed provides the higher the bands percentage and reduction of percentages of pure seed and inert material. The percentage of inert material was higher for seeds collected in the discharge pipe. The speed increase has positively influenced the emergence in sand for the harvester oldest (4 years) and negatively to the harvester youngest (3 years). At lower speeds the youngest harvester higher percentage of germination in sand.

The effect of locked screw angulation on the biomechanical properties of the S.P.S. Free-Block plate

Objectives: Among the locked internal fixators is one denominated S.P.S. (Synthesis Pengo System) Free-Block, which was designed with a locking ring that allows the screw to be locked and positioned obliquely. Due to the paucity of biomechanical studies on this system, the present work aimed to evaluate the influence of locked screw angulation on the resistance of the S.P.S. Free--Block plate. Methods: Forty synthetic bone cylinders with 10 mm fracture gap were used. Forty seven-hole 3.5 mm stainless steel plates (two AO-like dynamic compression holes and five locked holes) were assembled according to the orientation of the locked screws: mono cortical screws were positioned at 90° to the long axis of the cylinder (Group 1), and monocortical screws were positioned at 70° to its cylinder long axis (Group 2). In both groups, AO-like dynamic compression hole screws were positioned bicortically and neutrally. For each group, six specimens were tested until failure, three in bending and three in compression, to determine the loads for fatigue testing. Subsequently, for each group, 14 specimens were tested for failure --seven by bending and seven in compression. Results: No significant failure differences were observed between Groups 1 and 2 under static-loading or fatigue test. Clinical significance: In a fracture gap model the orientation of the locked monocortical screws did not show any influence on the mechanical performance of the S.P.S. Free-Block to tests of axial compression and four-point bending. © Schattauer 2013.

Estudo por simulação computacional da interação entre polianfóteros fracos e macroíons cilíndricos

Pós-graduação em Biofísica Molecular - IBILCE

Estudo do escoamento ao redor de cilindros elípticos

Pós-graduação em Engenharia Mecânica - FEIS