Fenologia e dendrocronologia de duas espécies de Fabaceae em uma área de cerrado no sudeste do Brasil

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

Interface Formation and Electrical Transport in SnO2:Eu3+/GaAs Heterojunction Deposited by Sol-Gel Dip-Coating and Resistive Evaporation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Silk formation mechanisms in the larval salivary glands of Apis mellifera (Hymenoptera : Apidae)

The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well as for scanning and transmission electron microscopy. The results showed that silk formation starts at the middle of the 5th instar and finishes at the end of the same instar. This process begins in the distal secretory portion of the gland, going towards the proximal secretory portion; and from the periphery to the center of the gland lumen. The silk proteins are released from the secretory cells as a homogeneous substance that polymerizes in the lumen to form compact birefringent tactoids. Secondly, the water absorption from the lumen secretion, carried out by secretory and duct cells, promotes aggregation of the tactoids that form a spiral-shape filament with a zigzag pattern. This pattern is also the results of the silk compression in the gland lumen and represents a high concentration of macromolecularly well-oriented silk proteins.

Carbon dioxide formation during initial stages of photodegradation of poly(ethyleneterephthalate) (PET) films

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

In Situ and Simultaneous UV-vis/SAXS and UV-vis/XAFS Time-Resolved Monitoring of ZnO Quantum Dots Formation and Growth

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

CROCODYLOMORPH EGGS and EGGSHELLS FROM THE ADAMANTINA FORMATION (BAURU GROUP), UPPER CRETACEOUS of BRAZIL

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Bone healing pattern in surgically created circumferential defects around submerged implants: an experimental study in dog

Objective: To describe the healing of marginal defects below or above 1 mm of dimension around submerged implants in a dog model.Material and methods: In 12 Labrador dogs, all mandibular premolars and first molars were extracted bilaterally. After 3 months of healing, full-thickness flaps were elevated in the edentulous region of the right side of the mandible. Two recipient sites were prepared and the marginal 5mm were widened to such an extent to obtain, after implant installation, a marginal gap of 0.5mm at the mesial site (small defect) and of 1.25mm at the distal site (large defect). Titanium healing caps were affixed to the implants and the flaps were sutured allowing a fully submerged healing. The experimental procedures were subsequently performed in the left side of the mandible. The timing of the experiments and sacrifices were planned in such a way to obtain biopsies representing the healing after 5, 10, 20 and 30 days. Ground sections were prepared and histomorphometrically analyzed.Results: The filling of the defect with newly formed bone was incomplete after 1 month of healing in all specimens. Bone formation occurred from the base and the lateral walls of the defects. A larger volume of new bone was formed in the large compared with the small defects. Most of the new bone at the large defect was formed between the 10- and the 20-day period of healing. After 1 month of healing, the outline of the newly formed bone was, however, located at a similar distance from the implant surface (about 0.4mm) at both defect types. Only minor newly formed bone in contact with the implant, starting from the base of the defects, was seen at the large defects (about 0.8mm) while a larger amount was detected at the small defects (about 2.2 mm).Conclusion: Marginal defects around titanium implants appeared to regenerate in 20-30 days by means of a distance osteogenesis. The bone fill of the defects was, however, incomplete after 1 month.

Invertebrates from the Low Head Member (Polonez Cove Formation, Oligocene) at Vaureal Peak, King George Island, West Antarctica

Eight taxa of marine invertebrates, including two new bivalve species, are described from the Low Head Member of the Polonez Cove Formation (latest early Oligocene) cropping out in the Vaureal Peak area, King George Island, West Antarctica. The fossil assemblage includes representatives of Brachiopoda (genera Neothyris sp. and Liothyrella sp.), Bivalvia (Adamussium auristriatum sp. nov., ?Adamussium cf. A. alanbeui Jonkers, and Limatula (Antarctolima) ferraziana sp. nov.), Bryozoa, Polychaeta (serpulid tubes) and Echinodermata. Specimens occur in debris flows deposits of the Low Head Member, as part of a fan delta setting in a high energy, shallow marine environment. Liothyrella sp., Adamussium auristriatum sp. nov. and Limatula ferraziana sp. nov. are among the oldest records for these genera in King George Island. In spite of their restrict number and diversification, bivalves and brachiopods from this study display an overall dispersal pattern that roughly fits in the clockwise circulation of marine currents around Antarctica accomplished in two steps. The first followed the opening of the Tasmanian Gateway at the Eocene/Oligocene boundary, along the eastern margin of Antarctica, and the second took place in post-Palaeogene time, following the Drake Passage opening between Antarctic Peninsula and South America, along the western margin of Antarctica.

Mechanisms of surface-relief gratings formation in layer-by-layer films from azodyes

Surface-relief gratings are photoinscribed on ionically adsorbed layer-by-layer (LBL) films of an azodye, Brilliant Yellow (BY), which was layered alternately with a polyelectrolyte. Photoinscription is performed by impinging an interference pattern of p- or s-polarized laser light with moderate intensity onto the LBL film, which is unlikely to cause thermal effects. Large-scale mass transport occurs due to the force associated with the field gradient of the light pattern. The ionic interactions between adjacent layers appear to provide the means for the chromophores to drag the polymer chains upon photoizomerization. LBL films were produced from two different polyelectrolytes and under two distinct pH values leading to markedly different film properties especially concerning photodegradation. Exposure to the laser light, for instance, leads to higher photodegradation in the poly(dimethyl diallylammonium chloride)/BY system, in comparison to the poly(allylamine hydrochloride)/BY films. Mass transport in the latter case is predominantly light-driven, which is consistent with the higher amplitude of modulation for p-polarized light (70 nm) compared to that caused by s-polarized light (18 nm). © 2003 Elsevier Ltd. All rights reserved.

Early healing pattern of autogenous bone grafts with and without e-PTFE membranes: A histomorphometric study in rats

Objective. The aim of this study was to perform quantitative and qualitative analyses of the initial repair pattern of an autogenous bone block graft when covered or not with e-PTFE membranes. Study design. Sixty male Wistar rats received a bone graft plus an e-PTFE membrane (MB) or just the graft (B). A block graft was harvested from the animal's calvarium and was laid and stabilized on the external cortical area near the angle of the mandible. Descriptive histology and histomorphometric analyses were carried out and the data were analyzed statistically by ANOVA and the Tukey test, with the level of significance set at 5%. Results. The results for group B showed that there was bone loss during the healing period (B0 = 1.38, B45 = 1.05, F = 7.91 > F C = 3.02), that is, the initial volume of the graft decreased in time. Bone tissue loss was about 24%. In contrast, the MB group showed bone tissue gain along the observation period (MB0 = 1.54, MB45 = 2.40, F = 7.91 > FC = 3.02), meaning that the total volume of newly formed bone was greater than the original graft area. Bone tissue gain was approximately 55%. MB showed significantly greater bone gain when compared to B (B45 = 1.05, MB45 = 2.40, F = 39.86 > FC = 1.90). These significant differences between B and MB could already be observed after 21 days. Conclusions. The bone block graft underwent resorption at an early healing stage, while additional new bone formation was observed when the bone graft was covered with an e-PTFE membrane. © 2005 Mosby, Inc. All rights reserved.

Bone-healing pattern at the surface of titanium implants: An experimental study in the dog

Objective: To study the early sequential stages of osseointegration at implants installed in alveolar bony. Materials and methods: In 12 Labrador dogs, all mandibular premolars and first molars were extracted bilaterally. After 3 months of healing, full-thickness flaps were elevated in the edentulous region of the right side of the mandible. Implants were installed, and the flaps were sutured to allow a fully submerged healing. The timing of the installations in the left side of the mandible and of sacrifices were performed with a schedule that various observation periods to sacrifice from 5, 10, 20, and 30 days were available so that n = 6 was obtained per each healing period. Ground sections were prepared and analyzed. Results: Newly formed bone in contact with the implant surface was found after 10 days of healing and the percentage increased up to 50% after 1 month of healing. A higher percentage was found in the trabecular compared with the cortical bony compartment. Old bone decreased by about 50% during healing, being still present after 1 month (16%). The proportions of bone debris and bone particles were at 27% after 5 days and decreased during healing to 6% after 1 month. Conclusion: Osseointegration (new bone-to-implant contact) developed at various rates for cortical and trabecular compartments, respectively. In the trabecular region, mesenchymal cells were identified, subsequently developing into new bone in contact with the implant surface. In the cortical compartment, however, resorptive processes were observed throughout all periods of healing. The proportion of newly formed bone percentage was lower compared with that of the trabecular area. Old bone was still present after 1 month of healing in both compartments. Bone debris and small bone particles appeared to be involved in initial bone formation. © 2013 John Wiley & Sons A/S.

Dissection of the role of pili and type 2 and 3 secretion systems in adherence and biofilm formation of an atypical enteropathogenic escherichia coli strain

Atypical enteropathogenic Escherichia coli (aEPEC) strains are diarrheal pathogens that lack bundle-forming pilus production but possess the virulence-associated locus of enterocyte effacement. aEPEC strain 1551-2 produces localized adherence (LA) on HeLa cells; however, its isogenic intimin (eae) mutant produces a diffuse-adherence (DA) pattern. In this study, we aimed to identify the DA-associated adhesin of the 1551-2 eae mutant. Electron microscopy of 1551-2 identified rigid rod-like pili composed of an 18-kDa protein, which was identified as the major pilin subunit of type 1 pilus (T1P) by mass spectrometry analysis. Deletion of fimA in 1551-2 affected biofilm formation but had no effect on adherence properties. Analysis of secreted proteins in supernatants of this strain identified a 150-kDa protein corresponding to SslE, a type 2 secreted protein that was recently reported to be involved in biofilm formation of rabbit and human EPEC strains. However, neither adherence nor biofilm formation was affected in a 1551-2 sslE mutant. We then investigated the role of the EspA filament associated with the type 3 secretion system (T3SS) in DA by generating a double eae espA mutant. This strain was no longer adherent, strongly suggesting that the T3SS translocon is the DA adhesin. In agreement with these results, specific anti-EspA antibodies blocked adherence of the 1551-2 eae mutant. Our data support a role for intimin in LA, for the T3SS translocon in DA, and for T1P in biofilm formation, all of which may act in concert to facilitate host intestinal colonization by aEPEC strains. ©2013, American Society for Microbiology.

Pattern recognition issues on anisotropic smoothed particle hydrodynamics

This is a preliminary theoretical discussion on the computational requirements of the state of the art smoothed particle hydrodynamics (SPH) from the optics of pattern recognition and artificial intelligence. It is pointed out in the present paper that, when including anisotropy detection to improve resolution on shock layer, SPH is a very peculiar case of unsupervised machine learning. On the other hand, the free particle nature of SPH opens an opportunity for artificial intelligence to study particles as agents acting in a collaborative framework in which the timed outcomes of a fluid simulation forms a large knowledge base, which might be very attractive in computational astrophysics phenomenological problems like self-propagating star formation.

Modeling the formation and propagation of desiccation cracks in soils

The problem of desiccation cracks in soils has received increasing attention in the last few years, in both experimental investigations and modeling. Experimental research has been mainly focused on the behavior of slurries subjected to drying in plates of different shapes, sizes and thickness. The main objectives of these studies were to learn about the process of crack formation under controlled environmental conditions, and also to better understand the effect of different factors (e.g. soil type, boundary conditions, soil thickness) on the morphology of the crack network. As for the numerical modeling, different approaches have been suggested lately to describe the behavior of drying cracks in soils. One aspect that it is still difficult to describe properly is the crack pattern observed in desiccated soils. This work presents a novel technique to model the behavior of drying soils. The crack patter observed in desiccation tests on circular plates are simulated with the main objective of predicting the effect of soil thickness on crack pattern. Good agreement between experimental results and model prediction are observed.