88 resultados para area of occupancy


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This study investigated the effect of an Argon-based nonthermal plasma (NTP) surface treatment-operated chairside at atmospheric pressure conditions applied immediately prior to dental implant placement in a canine model. Surfaces investigated comprised: Calcium-Phosphate (CaP) and CaP + NTP (CaP-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 2 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 Ca, C, O, and P for the CaP and CaP-Plasma surfaces. Both surfaces presented carbon primarily as hydro-carbon (CAC, CAH) with lower levels of oxidized carbon forms. The CaP surface presented atomic percent values of 38, 42, 11, and 7 for C, O, Ca, and P, respectively, and the CaPPlasma presented increases in O, Ca, and P atomic percent levels at 53, 12, and 13, respectively, in addition to a decrease in C content at 18 atomic percent. At 1 week no difference was found in histometric parameters between groups. At 3 weeks significantly higher BIC and BAFO were observed for CaPPlasma treated surfaces. Surface elemental chemistry was modified by the Ar-based NTP. Ar-based NTP improved bone formation around plateau-root form implants at 3 weeks compared with CaP treatment alone. © 2012 Wiley Periodicals, Inc.

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The surface energy of the implant surface has an impact on osseointegration. In this study, 2 surfaces: nonwashed resorbable blasting media (NWRBM; control) and Ar-based nonthermal plasma 30 days (Plasma 30 days; experimental), were investigated with a focus on the surface energy. The surface energy was characterized by the Owens-Wendt-Rabel-Kaelble method and the chemistry by X-ray photoelectron spectroscopy (XPS). Five adult beagle dogs received 8 implants (n = 2 per surface, per tibia). After 2 weeks, the animals were euthanized, and half of the implants (n = 20) were removal torqued and the other half were histologically processed (n = 20). The bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) were evaluated on the histologic sections. The XPS analysis showed peaks of C, Ca, O, and P for the control and experimental surfaces. While no significant difference was observed for BIC parameter (P > 0.75), a higher level for torque (P < 0.02) and BAFO parameter (P < 0.01) was observed for the experimental group. The surface elemental chemistry was modified by the plasma and lasted for 30 days after treatment resulting in improved biomechanical fixation and bone formation at 2 weeks compared to the control group. © 2013 Fernando P. S. Guastaldi et al.

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Purposes: The purposes of this study were to evaluate the influence of chronic stress (CS) on implant osseointegration and also to analyze whether alendronate (ALN) therapy could prevent these eventual stress-negative effects. Materials and Methods: Adult male Holtzmann rats were assigned to one of the four experimental groups: AL (ALN; 1mg/kg/week; n=12), ALS (ALN+CS; 1mg/kg/week; n=12), CTL (sterile physiological saline; n=12), or CTLS (sterile physiological saline+CS; n=12). After 58 days of drug therapy, the ALS and CTLS groups were exposed to CS, and 2 days later all animals underwent tibial implant installation. The animals were euthanized 28 days following the operative surgical procedure. Results: It was observed that the CTLS group presented an impairment of bone metabolism represented by lowest levels of bone-specific alkaline phosphatase and bone area fraction occupancy values. Furthermore, these animals presented a higher proportion of empty osteocytic lacunae. In contrast, the ALN therapy showed increased osseointegration and torque value parameters, regardless of stress exposition. Conclusions: Analysis of the data presented suggests that CS partially impairs the osseointegration of tibial implants and that ALN therapy is able to prevent these negative effects. © 2013 Wiley Periodicals, Inc.

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Application of recombinant human bone morphogenetic protein 2 (rhBMP-2) to implant surfaces has been of great interest due to its osteoinductive potential. However, the optimal coating methodology has not been clarified. The objective of the study was to determine whether the application of rhBMP-2 onto plasma-sprayed hydroxyapatite implant surfaces by immersion in protein solution before implant installation would result in significantly improved bone apposition. Using a sheep iliac model, titanium (Ti) and plasma-sprayed calcium-phosphate (PSCaP)-coated implants uncoated and coated with rhBMP-2 were assessed for their osteogenic effects in the peri-implant area over time in terms of osseointegration and de novo bone formation. After 3 and 6 weeks postoperatively, the samples were retrieved and were subjected to bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) evaluation. When rhBMP-2 was applied to the PSCaP surface, significant increases in BIC and BAFO were observed at 3 weeks in vivo, whereas when adsorbed directly onto the titanium implant surface, rhBMP-2 did not as effectively improve the bone response (although significantly higher than control Ti). The outcomes of the present study suggested that the combination of plasma-sprayed calcium-phosphate surface and rhBMP-2 coating significantly enhanced osseointegration, which validated the postulated hypothesis. © 2013 Wiley Periodicals, Inc.

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Background and Aims: Recent studies showed a positive tree response to Na addition in K-depleted tropical soils. Our study aimed to gain insight into the effects of K and Na fertilizations on leaf area components for a widely planted tree species. Methods: Leaf expansion rates, as well as nutrient, polyol and soluble sugar concentrations, were measured from emergence to abscission of tagged leaves in 1-year-old Eucalyptus grandis plantations. Leaf cell size and water status parameters were compared 1 and 2 months after leaf emergence in plots with KCl application (+K), NaCl application (+Na) and control plots (C). Results: K and Na applications enhanced tree leaf area by increasing both leaf longevity and the mean area of individual leaves. Higher cell turgor in treatments +K and +Na than in the C treatment resulting from higher concentrations of osmotica contributed to increasing both palisade cell diameters and the size of fully expanded leaves. Conclusions: Intermediate total tree leaf area in treatment +Na compared to treatments C and +K might result from the capacity of Na to substitute K in osmoregulatory functions, whereas it seemed unable to accomplish other important K functions that contribute to delaying leaf senescence. © 2013 Springer Science+Business Media Dordrecht.

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Background: Iran is an area of particular interest for investigating goat diversity. Archaeological remains indicate early goat domestication (about 10 000 years ago) in the Iranian Zagros Mountains as well as in the high Euphrates valley and southeastern Anatolia. In addition, mitochondrial DNA data of domestic goats and wild ancestors (C. aegagrusor bezoar) suggest a pre-domestication management of wild populations in southern Zagros and central Iranian Plateau. In this study genetic diversity was assessed in seven Iranian native goat breeds, namely Markhoz, Najdi, Taleshi, Khalkhali, Naini, native Abadeh and Turki-Ghashghaei. A total of 317 animals were characterized using 14 microsatellite loci. Two Pakistani goat populations, Pahari and Teddy, were genotyped for comparison.Results: Iranian goats possess a remarkable genetic diversity (average expected heterozygosity of 0.671 across loci, 10.7 alleles per locus) mainly accounted for by the within-breed component (G(ST) = 5.9%). Positive and highly significant F-IS values in the Naini, Turki-Ghashghaei, Abadeh and Markhoz breeds indicate some level of inbreeding in these populations. Multivariate analyses cluster Iranian goats into northern, central and western groups, with the western breeds relatively distinct from the others. Pakistani breeds show some relationship with Iranian populations, even if their position is not consistent across analyses. Gene flow was higher within regions (west, north, central) compared to between regions but particularly low between the western and the other two regions, probably due to the isolating topography of the Zagros mountain range. The Turki-Ghashghaei, Najdi and Abadeh breeds are reared in geographic areas where mtDNA provided evidence of early domestication. These breeds are highly variable, located on basal short branches in the neighbor-joining tree, close to the origin of the principal component analysis plot and, although highly admixed, they are quite distinct from those reared on the western side of the Zagros mountain range.Conclusions: These observations call for further investigation of the nuclear DNA diversity of these breeds within a much wider geographic context to confirm or re-discuss the current hypothesis (based on maternal lineage data) of an almost exclusive contribution of the eastern Anatolian bezoar to the domestic goat gene pool.

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

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The results of ecological restoration techniques can be monitored through biological indicators of soil quality such as the leaf litter arthropod fauna. This study aimed to determine the immediate effect of brushwood transposition transferred from an area of native vegetation to a disturbed area, on the leaf litter arthropod fauna in a degraded cerrado area. The arthropod fauna of four areas was compared: a degraded area with signal grass, two experimental brushwood transposition areas, with and without castor oil plants, and an area of native cerrado. In total, 7,660 individuals belonging to 23 taxa were sampled. Acari and Collembola were the most abundant taxa in all studied areas, followed by Coleoptera, Diptera, Hemiptera, Hymenoptera, and Symphyla. The brushwood transposition area without castor oil plants had the lowest abundance and dominance and the highest diversity of all areas, providing evidence of changes in the soil community. Conversely, the results showed that the presence of castor oil plants hampered early succession, negatively affecting ecological restoration in this area.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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

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Processo FAPESP: 2012/24545-3

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This article analyzes the inclusion of the issue of “environmental management” in the department of Production Engineering of the “Alfa” School of Engineering. For this, a case study was conducted at the School of "Alpha" Engineering, with a focus on the area of Production Engineering. Professors were interviewed; documents were reviewed as well as information collected from direct observations by of one of the authors of this article. It was observed that the department of Production Engineering at the Alpha School of Engineering has been developing activities covering all those aspects proposed by Jabbour [8]. "Environmental management" has been included in the curriculums of: (a) Teaching: in the creation of undergraduate courses (obligatory) and graduate Master's degree (optional), (b) Research: formalization of research groups in environmental management for the creation of master’s post graduation research, formalization of environmental management as one of the subjects that should be chosen by candidates for a Professorship in the area of production engineering; (c) Extension: Course in Environmental Management, Symposium (which in recent years has been focusing on environmental issues), creation of sustainability indicators for universities, (d) University Management: initiatives to raise awareness, distribution of reusable mugs and installation of special bins for selective collection in the Campus.