Ocorrência de fungos negros em ambientes domésticos

Black fungi are able to adapt to extreme environmental conditions, such as: high temperatures, the presence of toxic chemical substances and lack of nutrients. Besides, they are also potential pathogens to humans. The natural environment of many black fungi is still unknown and some studies are being conducted to evaluate the biodiversity of this group and their different habitats. This study aimed to isolate black fungi in domestic environments and facilities, such as toothbrushes, fridge sealing rubbers, bathroom strainers and divisions, windows, wall tiles and bath sponge. For the collection, material surfaces were scratched with a scalpel and the resulting fragments were sewed in Mycosel agar (DifcoTM), supplemented with actidione to inhibit the growth of highly-sporulating fungi. Plates were incubated at 25ºC for three weeks. The 46 isolated fungi were maintained on MA2% slants at 8ºC and cryopreserved at -80ºC. Fungal identification was performed through the analysis of macro and microscopic features and ITS rDNA sequencing. The following black fungi taxa were found: Ascomycota sp., Cladosporium spp., Dothideomycete sp., Exophiala alcalophila, Ochroconis mirabilis and Rhinocladiella atrovirens. Non-melanized fungi were also found, such as Geosmithia sp., Penicillium sp. and Rhodotorula mucilaginosa. The temperature tests showed that isolated black fungi were not able to grow at 37°C, however, this temperature proved to be fungistatic to 43% of them. According to literature, all black fungi isolated in this study are opportunistic pathogens and additional studies are necessary to evaluate the risk that these micro-organisms offer to health, once they were isolated from domestic environments

Obtenção e caracterização de nanocelulose a partir de fibras de Chorisia speciosa St. Hil

Natural fibers have been highlighted as a renewable material that can replace materials from oil and its derivatives. In this context, Brazil becomes the perfect setting because of the diversity of fibers found in its territory, such as sugarcane, sisal, rice, cotton, coconut, pineapple, among others. The paineiras (Chorisia speciosa St. Hil) are typically Brazilian trees, which produce paina as fruit. These fruits are still little studied as a source of lignocellulose by research groups. This project aimed obtaining and characterization of cellulose nanofibers from the fibers from the paina fibers. Obtaining nanocellulose is practically made through simplified chemical processes. First, was performed out pre-treatments to removal of waxes, lignin and hemicellulose. The first stage of pre-treatment was carried out by alkaline aqueous solution of sodium hydroxide (NaOH) at 5wt%, where the fibers were under constant agitation for 1h at 70°C. Through alkali treatment it was possible to remove most of the lignin, hemicellulose, waxes and extractives. After the alkaline treatment was done bleaching with an aqueous solution of sodium hydroxide (NaOH) to 4wt% and hydrogen peroxide (H2O2) to 24wt% 1:1 during 2h with constant stirring to 50 °C. Through bleaching was possibe to remove residual lignin, and got cellulose with 72% of crystallinity. Nanocellulose of paina fibers was extracted using different conditions of acid hydrolysis with sulfuric acid (H2SO4) to 50wt%. After acid hydrolysis, the suspensions were centrifuged during 30 min and dialyzed in water to remove excess acid until neutral pH (6-7). Then the suspensions were passed by ultrasonification in an ultrasound 20 kHz during 1h in an ice bath. Untreated, alkalinized and bleached fibers as well as cellulose nanoparticles were characterized by the techniques of thermogravimetry ... (Complete abastract click electronic access below)

Estudo da viabilidade de produção da peça alimentação/ladrão para banheiras

The product development field daily works in the chase of new materials and technologies that fulfills the requirements of the consumer market. So, projects are developed in order to theoretically predict what will actually happen. The production of household appliance is not different. To provide a pleasant bath to the costumer, the manufacture of a bathtub counts on many components. With this in mind, this work goal is to study the possibility of production by plastic injection of the assembly water source/overflow pipe used in bathtubs and compare its production cost with the cost of the assembly acquired from third parties. The injection process is widely used on the world stage because of its numerous advantages, however, due to the high cost of the molds, it is important to estimate the time required for the return of the initial investment. To do this, a model was designed to examine its dimensions and then initiate the study of the possibility to inject the components with the available injection machine and the production cycle. With the results, it was found that there was a reduction in the cost of the finished assembly, but a very long time to return the initial investment due to the current financial scenery of the country