Estudo comparativo entre a pirólise do polietileno de baixa densidade, utilizando vermiculita modificada e SBA-15

Catalytic processes are widely present in everyday life. This results in large number of studies seeking materials that may combine the low cost catalytic efficiency. Based on this assumption, the clays have long been used as catalysts, with its huge availability, diversity and possibility of improving their properties from structural changes, primarily responsible for this great use. Among the natural clays, vermiculite due to their characteristic properties (high cation exchange capacity and expansion), is suitable for various applications including as catalysts and catalyst supports. In this work, the acid leaching of clay vermiculite was performed, coming from Santa Luzia-PB, with nitric acid (2, 3 and 4 mol / L) and subsequent calcination of the materials obtained. The materials were named as Vx/400, where x is the acid concentration employed and 400 used in calcination temperature. The effectiveness of changes made was determined by XRD techniques, FT-IR, EDS, TG/DTG, nitrogen physisorption and DTP of n-butylamine. Acid leaching has improved some properties of the clay - specific area and acidity - but the control of the acid concentration used is of vital importance, since the highest concentration caused the partial destruction of vermiculite entailing a decline in their properties. For analysis of the catalytic activity of the modified clay was made a comparative study with the SBA -15 mesoporous materials, synthesized via hydrothermal method, using the pyrolysis of low density polyethylene (LDPE). The results showed that the acid plays a fundamental role in the conversion of the polymer into smaller molecules, the material V3/400 was more selective for the source monomer (ethylene) due to their increased acidity, which promotes more breaks bonds in the polymeric chain, while materials and V0/400 V2/400, lower acidity, showed higher selectivity to light hydrocarbons, the range of fuel (41.96 and 41.23%, respectively), due to less breakage and secondary condensation reactions chains; already V4/400 SBA-15/550 and resulted in lower percentages of light hydrocarbons and the partial destruction of the structure and low acidity, respectively, responsible for the inefficiency of materials

As transformações fundiárias da comunidade de sibaúma-rn com o advento do turismo

The genesis of the research emerges from reflection about the space dynamics of the capital and to the capital. The expansion and the incorporation of territory for capital reveal, in part, strategies of the capitalism production way, which shows the search for accumulation conditions, expanding the alternatives of territory use that is, nowadays, selective and uneven. The present work verified the mechanisms where the capital imposes its practices through the agrarian structure and the valuation of land market, meaning, in our knowledge, that the reproduction of inequalities is showed, many times, by the wide land speculation and the fast land valuation. For this, the snip space will be the Sibaúma community, belonging to Tibau do Sul district, located in Rio Grande do Norte state. It‟s a rural area that has, gradually, changing through the advent of urban characteristics, given the association of public and private investments, both domestic and international. Through the empirical observations, inside the Sibaúma community, it was found expansion strategies, incorporation and appropriation of territory by capital. As a result of this practice, it‟s occurring the land valuation and the presence of a process of socio-spatial segregation, through the encouraging the opening of new subdivisions, mainly for construction of second homes and tourism enterprises in order to meet the demand of a higher socioeconomic level. The areas still available in Sibaúma, constitute into a reserve of value for the achievement of capitalist rent, being a mechanism of capital reproduction. In this way, to studying the socio-spatial transformations, caused by spatial valuation, we turn to the project of social space designed by Santos(2006), from the perspective of capitalist production of space, by understanding the historical process of formation, the mechanisms and the actions of social actors that produce and consume space

Leukotriene B(4) is essential for selective eosinophil recruitment following allergen challenge of CD4(+) cells in a model of chronic eosinophilic inflammation

Subcutaneous heat-coagulated egg white implants (EWI) induce chronic, intense local eosinophilia in mice, followed by asthma-like responses to airway ovalbumin challenge. Our goal was to define the mechanisms of selective eosinophil accumulation in the EWI model. EWI carriers were challenged i.p. with ovalbumin and the contributions of cellular immunity and inflammatory mediators to the resulting leukocyte accumulation were defined through cell transfer and pharmacological inhibition protocols. Eosinophil recruitment required Major Histocompatibility Complex Class It expression, and was abolished by the leukotriene B4 (LTB4) receptor antagonist CP 105.696, the 5-lipoxygenase inhibitor BWA4C and the 5-lipoxygenase activating protein inhibitor MK886. Eosinophil recruitment in EWI carriers followed transfer of: a) CD4(+) (but not CD4(-)) cells, harvested from EWI donors and restimulated ex vivo; b) their cell-free supernatants, containing LTB4. Restimulation in the presence of MK886 was ineffective. CC chemokine receptor ligand (CCL)5 and CCL2 were induced by ovalbumin challenge in vivo. mRNA for CCL17 and CCL11 was induced in ovalbumin-restimulated CD4(+) cells ex vivo. MK886 blocked induction of CCL17 Pretreatment of EWI carriers with MK886 eliminated the effectiveness of exogenously administered CCL11, CCL2 and CCL5. In conclusion, chemokine-producing, ovalburnin-restimulated CD4(+) cells initiate eosinophil recruitment which is strictly dependent on LTB4 production. (C) 2008 Elsevier B.V. All rights reserved.

Photographic assessment of nasal morphology following rapid maxillary expansion in children

Objective: The aim of the present study was to use facial analysis to determine the effects of rapid maxillary expansion (RME) on nasal morphology in children in the stages of primary and mixed dentition, with posterior cross-bite. Material and Methods: Facial photographs (front view and profile) of 60 patients in the pre-expansion period, immediate post-expansion period and one year following rapid maxillary expansion with a Haas appliance were evaluated on 2 occasions by 3 experienced orthodontists independently, with a 2-week interval between evaluations. The examiners were instructed to assess nasal morphology and had no knowledge regarding the content of the study. Intraexanniner and interexanniner agreement (assessed using the Kappa statistic) was acceptable. Results: From the analysis of the mode of the examiners' findings, no alterations in nasal morphology occurred regarding the following aspects: dorsunn of nose, alar base, nasal width of middle third and nasal base. Alterations were only detected in the nasolabial angle in 1.64% of the patients between the pre-expansion and immediate post-expansion photographs. In 4.92% of the patients between the immediate post-expansion period and 1 year following expansion; and in 6.56% of the patients between the pre-expansion period and one year following expansion. Conclusion: RME performed on children in stages of primary and mixed dentition did not have any impact on nasal morphology, as assessed using facial analysis.

Rapid palatal expansion: a comparison of two appliances

This study analyzed occlusal radiographs to compare the transverse changes produced in patients treated with rapid maxillary expansion using two types of appliances. The sample consisted of 31 children aged 7 to 10.6 years, of both genders, with posterior cross-bite. Fifteen children were treated with a tooth-borne expander and 16 were treated with a tooth-tissue-borne expander. Occlusal radiographs obtained at treatment onset and at the end of the retention period were digitized. The following variables were measured: intermolar distance (IMD), interapical distance (IApD), interbase distance (IBaD) and interarm distance (IArD). The results revealed increases in all measurements in both groups after rapid maxillary expansion. Comparison between groups revealed that the increases were greater in patients treated with the tooth-borne expander, except for the IArD measurement, which presented the same increase in both groups. Even though the IMD measurements differed between expanders, they were proportional to the activation of the appliances (IBaD). The increase in the IApD measurement was proportionally greater in the group treated with the tooth-borne expander (0.7:1.0) than in that treated with the tooth-tissue-borne expander (0.4:1.0). It was concluded that both appliances had similar effects, although the tooth-tissue-borne expander produced a lesser opening at the apical region of the incisors.

Accidental swallowing of orthodontic expansion appliance key

Ingestion of a foreign object, including a dental object, can lead to a trip to the emergency room. This article describes the accidental swallowing of a key that was used to activate a rapid maxillary expander. An orthodontic patient swallowed the key while trying to activate the appliance at home. The object's trajectory was followed on radiographs until it was eliminated. Possible clinical complications, legal implications of this situation, and practices for prevention are described. (Am J Orthod Dentofacial Orthop 2011;140:266-8)

Effect of selective cyclooxygenase-2 inhibition on the development of ligature-induced periodontitis in rats

Background: the purpose of this study was to evaluate the effect of a selective cyclooxygenase-2 inhibitor on the progression of alveolar bone loss in an experimental periodontitis model in rats.Methods: One hundred eighty (180) Wistar rats were separated into 3 experimental groups. Cotton ligatures were placed at the gingival margin level of lower right first molars. The rats were randomly assigned to one of the following groups that received: a daily oral dose of 10 mg/kg body weight of celecoxib (Ce1); 20 mg/kg body weight of celecoxib (Ce2); or 10 ml/kg of saline solution (C). Serum levels of celecoxib and white blood cell count were determined. Standardized digital radiographs were taken after sacrifice at 3, 5, 10, 18, and 30 days to measure the amount of bone loss around the mesial root surface of the first molar tooth in each rat.Results: Two-way analysis of variance (ANOVA) indicated that groups treated with celecoxib had significantly less bone loss compared to controls (P <0.0001) and that there was a significant interaction between treatment with celecoxib and time (P <0.03). Post-hoc comparisons showed that in both groups treated with celecoxib, the bone loss became significant only after 10 days of ligature placement, while in the control group it was already significant after 5 days. However, differences in mean bone loss between control and Ce1 were significant only at 18 days and, between control and Ce2, at 5 and 18 days. There was no significant difference in bone loss among experimental groups at the end of the experimental period.Conclusion: These data provide evidence that systemic therapy with celecoxib can modify the progression of experimentally induced periodontitis in rats.

Soft tissue profile changes after rapid maxillary expansion with a bonded expander

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

Medium Chain Fatty Acids Are Selective Peroxisome Proliferator Activated Receptor (PPAR) gamma Activators and Pan-PPAR Partial Agonists

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

Selective isolation of dematiaceous fungi from the workers of Atta laevigata (Formicidae: Attini)

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

Water content and GA(3)-induced embryonic cell expansion explain Euterpe edulis seed germination, rather than seed reserve mobilisation

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

The impact of soybean expansion on mammal and bird, in the Balsas region, north Brasilian Cerrado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Expansion effects on back-to-back correlations

The back-to-back correlations (BBC) of particle-antiparticle pairs, signalling in-medium mass modification, are studied in a finite size thermalized medium. The width of BBC function is explicitly evaluated in the case of a nonrelativistic spherically symmetric expanding fireball. The effect of the flow is to reduce the BBC signal as compared to the case of non flow. Nevertheless, a significant signal survives finite-time emission plus expansion effects.