Browsing by Issue Date, starting with "2019-08-01"
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- Copper nanoparticles stabilized with cashew gum: Antimicrobial activity and cytotoxicity against 4T1 mouse mammary tumor cell linePublication . Amorim, Adriany; Mafud, Ana Carolina; Nogueira, Silvania; Ramos-Jesus, Joilson; Araújo, Alyne Rodrigues de; Plácido, Alexandra; Neta, Maria Brito; Alves, Michel Muálem Moraes; Carvalho, Fernando Aécio Amorim; Rufino Arcanjo, Daniel Dias; Braun, Sacha; López, Marta Sánchez-Paniagua; López-Ruiz, Beatriz; Delerue-Matos, Cristina; Mascarenhas, Yvonne; Silva, Durcilene; Eaton, Peter; Leite, José Roberto Souza AlmeidaCopper nanoparticles stabilized with cashew (CG-CuNPs) were synthesized by reduction reaction using ascorbic acid and sodium borohydride, using the cashew gum (CG) as a natural polymer stabilizer. Dynamic light scattering, atomic force microscopy, Fourier-transform infrared spectroscopy, UV-Vis spectrophotometry, and x-ray diffraction were used to characterize the nanoparticles (CG-CuNPs), and copper was quantified by electrochemical measurement. The UV-vis spectra of the CG-CuNPs confirmed the formation of nanoparticles by appearance of a surface plasmon band at 580 nm after 24 h of reaction. The Fourier-transform infrared spectrum of CG-CuNPs showed the peak at 1704 cm−1 from cashew gum, confirming the presence of the gum in the nanoparticles. The average size of CG-CuNPs by dynamic light scattering and atomic force microscopy was around 10 nm, indicating small, approximately spherical particles. Antimicrobial assays showed that CG-CuNPs had activity against Staphylococcus aureus ATCC 29213 with a minimal inhibitory concentration of 0.64 mM. The cytotoxicity assay on BALB/c murine macrophages showed lower cytotoxic effects for CG-CuNPs than CuSO4·5H2O. Viability cell assays for CG-CuNPs at (0.250 mM) inhibited by 70% the growth of 4T1 LUC (4T1 mouse mammary tumor cell line) and NIH 3T3 cells (murine fibroblast cells) over a 24-h period. Therefore, CG-CuNPs can be used as an antimicrobial agent with lower cytotoxic effects than the CuSO4·5H2O precursor.
- Internationalization of the ClepiTO web platformPublication . Carro, Eloy Naveira; Miranda-Duro, María del Carmen; Concheiro-Moscoso, Patricia; Castro, Alejandro Puente; Portugal, Paula Cristina Costa; Coelho, Tiago Filipe MotaThis adaptation consists of the translation from Spanish into Portuguese of the different contents offered by the ClepiTO web platform to be able to carry out a pilot test with a larger population in Portugal and thus be able to compare the results obtained among the Spanish and Portuguese population.
- Advanced Calculation Model Calibrated with Experimental Test of Wooden Slabs Exposed to FirePublication . Fonseca, Elza M M; Piloto, Paulo A GThe wooden slabs are structural elements with wide application, in particular, in building rehabilitation, interior spaces and in new building structures. The mechanical, thermal and acoustic properties make this material as an ideal solution for floor and roof slabs applications. However, when exposed to an accidental fire condition it is necessary to assess their vulnerable behaviour accurately. In this work, an advanced calculation model is presented, based on the use of finite elements, calibrated with experimental results. The experimental tests were performed on wooden slabs exposed to a fire from below the element. The slabs were instrumented with thermocouples to measure the temperature at different control points along the fire duration in a fire resistance furnace, following the standard fire curve ISO 834. The advanced calculation model also allows the obtained the transient effect and incorporates the non-linear wood properties. The physical behaviour of the wooden slab is conditioned by the char layer formation, and this phenomenon is also considered in the advanced calculation model.