Influence of the sodium content on the reactivity of carbon anodes

Spent anodes, denominated butts in the aluminum industry, are recycled as part of the raw material used to produce new anodes. The fragmentation of the butt generates some sodium-rich powder, which is captured and included in the recycled material. This paper evaluates the influence of sodium content on anode reactivity. Six formulations with 0 to 25% butt powder were used. An average increase of 48 ppm of sodium from one to another formulation caused average increments of 3.38 and 2.72% for air and CO2 reactivity, respectively. The quality-related figures varied from 1.34 to 1.12 for CO2 and from 1.10 to 0.62 for air, showing quality loss in higher sodium content and higher impact on air reactivity. The Fischer formula predicted a carbon specific consumption of - 48.47 kg.t-1 Al for baked carbon anodes with 127 ppm to 367 ppm of sodium content, showing that the sodium can cause relevant carbon losses and increase costs of the aluminum production.

The mineralogy and chemistry of the German and Portuguese tiles used to face a historic building in the Amazon region and their natural susceptibility to tropical weathering

As proeminentes edificações da cidade de Belém foram revestidas durante o século 19 com azulejos produzidos em Portugal e Alemanha que já apresentam distintos graus de degradação. O Palacete Pinho é uma das mais importantes destas edificações e foi selecionado para se investigar a ação do clima tropical amazônico sobre a degradação destes azulejos. Para atingir estes objetivos mapearam-se os azulejos desta edificação visando identificar as modificações de origem orgânica e inorgânica e coletas de amostras para análises. Os minerais foram determinados por DRX, a composição química por métodos clássicos úmidos e MEV/SED e os micro-organismos por microscopia. Os resultados obtidos mostram que os azulejos Portugueses e Alemães são distintos entre si. Enquanto o biscoito é composto de SiO₂ e Al₂O₃, CaO foi encontrado apenas nos Portugueses. Os baixos conteúdos de Na₂O e K₂O indicam adição de materiais para redução da temperatura de fusão. SiO₂ e PbO compõem o vidrado, já CoO e FeO foram adicionados como pigmentos. O biscoito dos azulejos Alemães é constituído de quartzo, mullita e cristobalita, ao contrário do Português com quartzo, gehlenita, diopsídio, calcita e feldspatos. Os vidrados são amorfos ao DRX. As diferenças químicas e mineralógicas entre os azulejos Portugueses e Alemães indicam que foram produzidos por matéria prima distinta, bem como processo termal. As alterações relacionadas com o intemperismo são as finas camadas de detritos (nos Alemães), manchas de oxidação, manchas escuras, descolamento do azulejo (no Português); perda de vidrado e biscoito tornando-se pulverulento como consequência do estabelecimento de Cyanophyta e bacillariophyta (Português). As distintas feições de degradação dos azulejos refletem as suas diferenças mineralógicas e químicas expostas ao clima tropical Amazônico.

SEM Evaluation of the Interface Between Filling and Root- End Filling Materials

The aim of this ex vivo study was to evaluate, by scanning electron microscopy (SEM), the presence of gaps at the interface between filling material and three root-end filling materials. Thirty human upper molars disto-buccal roots were instrumented and filled with gutta-percha and eugenol-based sealer. The apicoectomy was performed 2mm from the apex and retrograde cavities were prepared with ultrasonic points (3mm in deep). The samples were divided into three experimental groups (n=10): Group Iwhite mineral trioxide aggregate (MTA); Group IISuper EBA; and Group IIIPortland cement. The root-end filling materials were inserted into the retocavities using a MTA carrier. After 48h, the roots were transversally sectioned in order to obtain the apical 5mm. Next, each specimen was prepared longitudinally with crescent granulation of abrasives water-wet sandpapers in order to expose the filling and root-end filling materials. Then, the specimens were subjected to slow dehydration with silica gel, mounted onto specific stubs and coated with paladium coverage for SEM analysis of the interface between filling and root-end filling materials. The percentage of gaps at the interfacial area was calculated by using Image Tool 3.0 software. Super EBA presented the higher percentage of gaps (1.5 +/- 0.67%), whereas MTA presented the lowest values (0.33 +/- 0.20%; p=0.0004). Despite the statistical differences observed between Super EBA and MTA, all the root-end filling materials presented great adaptation to the filling material, presenting small amount of gaps. SCANNING 36:252-257, 2014. (c) 2013 Wiley Periodicals, Inc.

The use of radon (Rn-222) and volatile organic compounds in monitoring soil gas to localize NAPL contamination at a gas station in Rio Claro, Sao Paulo State, Brazil

This study focuses on the presence of radon (Rn-222) and volatile organic compounds (VOCs) in soil gases at a gas station located in the city of Rio Claro, Sao Paulo, Brazil, where a fossil fuel leak occurred. The spatial distribution results show a correlation between Rn-222 and VOCs, consistent with the fact that radon gas has a greater chemical affinity with organic phases than with water. This finding demonstrates that the presence of a residual hydrocarbon phase in an aquifer can retain radon, leading to a reduced radon content in the soil gas. The data in this study confirm the results of previous investigations, in which the method used in this study provided a preliminary fingerprint of a contaminated area. Furthermore, the data analysis time is brief, and only simple equipment is required. (C) 2014 Published by Elsevier Ltd.

Sampling density and proportion for the characterization of the variability of Oxisol attributes on different materials

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

Effect of the addition of antimicrobial agents on shore a hardness and roughness of soft lining materials

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

Zirconium-methacrylate oxoclusters as new hybrid materials for the modification of epoxy systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Assessment of the risk of raw milk consumption related to staphylococcal food poisoning

This study aimed to identify the risks of staphylococcal food poisoning due to the consumption of raw milk. Fifty-one farms in Londrina (PR) and 50 in Pelotas (RS) were analyzed, to determine the population of coagulase-positive staphylococci (UFC/ mL), as well as to verify the ability of producing Staphylococcal Enterotoxin A (SEA) by immunodifusion (OSP), the presence of the gene for the production of SEA (PCR) in the cultures, and the research of enterotoxin (SEA to SEE) in milk samples using ELISA commercial kit. Considering the 101 farms analyzed, 19 (18.8%) presented coagulase-positive staphylococci count above 105 UFC/mL. For the evaluation of the enterotoxigenic ability (SEA) by the OSP technique, six cultures coagulase-positive (5.5%) were positive to the test and identified as S. aureus. From the coagualse-negative sample, one (5.5%) was OSP positive. For the evaluation of the presence of the gene for EEA synthesis, 51 cultures of staphylococci were tested. From this total, 14 (27.45%) presented the gene, and from that, only 5 (9.81%) cultures were capable of expressing it in the technique of the OSP. The morphologic characteristic of the evaluated cultures that had enterotoxigenic capacity, from the 14 (33,3%) cultures that presented the gene for EEA production, 05 (11.9%) were characterized as typical cultures of S.aureus in Baird Parker agar. All the 12 milk samples studied for the presence of EEA to EEE in milk were negative. Thus, it can be concluded that there is extensive contamination of raw milk for staphylococci coagulase, however, most of the isolated strains were not enterotoxigenic or did not express such a characteristic. Only 9.81% of the tested colonies expressed the gene and effectively produced SEA. None of the samples had sufficient counts to produce detectable amounts of SEA. The milk samples did not present risk to cause staphylococcal food poisoning if consumed in natura until the collection moment.

Dynamic Viscosity of Implantable Autologous Materials Into the Vocal Fold

Objective. To compare the dynamic viscosity (DV) of superficial layer of temporalis fascia (SLTF) with that of other biological tissues traditionally used for vocal fold implants to treat vocal fold rigidity. Study Design. Experimental. Method. Measurement of DV of samples of SLTF, deep layer of temporalis fascia (DLTF), and abdominal fat of 12 cadavers. Results. DV values of the different samples were presented in the following increasing order: SLTF, DLTF, and abdominal fat. There was statistical difference between the samples. Conclusion. DV of SLTF is lower than of other tissues tested.

NF-κB Drives the Synthesis of Melatonin in RAW 264.7 Macrophages by Inducing the Transcription of the Arylalkylamine-N-Acetyltransferase (AA-NAT) Gene

We demonstrate that during inflammatory responses the nuclear factor kappa B (NF-kappa B) induces the synthesis of melatonin by macrophages and that macrophage-synthesized melatonin modulates the function of these professional phagocytes in an autocrine manner. Expression of a DsRed2 fluorescent reporter driven by regions of the aa-nat promoter, that encodes the key enzyme involved in melatonin synthesis (arylalkylamine-N-acetyltransferase), containing one or two upstream kappa B binding sites in RAW 264.7 macrophage cell lines was repressed when NF-kappa B activity was inhibited by blocking its nuclear translocation or its DNA binding activity or by silencing the transcription of the RelA or c-Rel NF-kappa B subunits. Therefore, transcription of aa-nat driven by NF-kappa B dimers containing RelA or c-Rel subunits mediates pathogen-associated molecular patterns (PAMPs) or pro-inflammatory cytokine-induced melatonin synthesis in macrophages. Furthermore, melatonin acts in an autocrine manner to potentiate macrophage phagocytic activity, whereas luzindole, a competitive antagonist of melatonin receptors, decreases macrophage phagocytic activity. The opposing functions of NF-kappa B in the modulation of AA-NAT expression in pinealocytes and macrophages may represent the key mechanism for the switch in the source of melatonin from the pineal gland to immune-competent cells during the development of an inflammatory response.

Isolation and characterization of the flour and starch of plantain bananas (Musa paradisiaca)

Plantain bananas of the variety Terra (Musa paradisiaca) may have industrial value due to their high starch content. In this research, the flour and starch of such unripe fruit were isolated and their chemical, physicochemical, and structural characteristics were determined. Banana flour and starch had a dry basis yield of 50.6 and 28.5%, and an average granule size of 31.7 and 47.3?mu m, respectively. Both raw materials revealed a C-type pattern and high gelatinization temperatures. The peak viscosity was greater for flour (378.0 RVU) than for starch (252.6 RVU), although the final viscosity was lower. At temperatures above 65 degrees C, the swelling power of banana flour was lower than that of starch, while the solubility of flour was greater than that of starch at all temperatures. Furthermore, the presence of other components in banana flour influenced its physicochemical properties. In general, the flour and starch processed from unripe bananas have numerous possible uses as ingredients in food systems and for other industrial purposes.

Clinical, radiographic and histologic analysis of the effects of pulp capping materials used in pulpotomies of human primary teeth

Aim: To compare the clinical, radiographic and histological responses of the pulp to mineral trioxide aggregate (MTA), calcium hydroxide (CH) and Portland cement (PC) when used as a pulpotomy agent in human primary teeth. Study design: Forty-five mandibular primary molar teeth were randomly assigned to CH, MTA or PC groups and treated by pulpotomy technique. Methods: The teeth were treated by conventional pulpotomy technique, differing only in the capping material for each group. Clinical and radiographic evaluations were recorded at 6-, 12- and 24-month follow-up. Teeth in the regular exfoliation period were further processed for histologic analysis. Statistics: The teeth were treated by conventional pulpotomy technique, differing only in the capping material for each group. Clinical and radiographic evaluations were recorded at 6-, 12- and 24-month follow-up. Teeth in the regular exfoliation period were further processed for histologic analysis. Statistics: Clinically and radiographically, the MTA and PC groups showed 100 % success rates at 6, 12 and 24 months. In CH group, several teeth presented clinical and radiographic failures detected throughout the follow-up period, and internal resorption was a frequent radiographic finding. Histologic analysis revealed the presence of dentine-like mineralised material deposition obliterating the root canal in the PC and MTA groups. CH group presented, in most of the sections, necrotic areas in the root canals. Conclusions: MTA and PC may serve as effective materials for pulpotomies of primary teeth as compared to CH. Although our results are very encouraging, further studies and longer follow-up assessments are needed in order to determine the safe clinical indication of Portland cement.