Kefir is a natural probiotic produced by kefir grains fermentation. Biofilms produced from fresh kefir grains in natura were studied for presenting structural characteristics that will be of great interest in the area of regenerative medicine. This work presents a study on the surface of kefir biofilms, obtained by the cultivation of kefir grains in commercial white sugar. Four different films were produced, varying the concentration of sugar. The crystallinity of the biofilms was analyzed and revealed that sugar concentration influences biofilm amorphousness. Morphology showed that the biofilms presented excellent superficial adhesiveness. Fractal parameters were studied and revealed that there was homogeneity in the biofilm microtexture. Both fractal succolarity and surface entropy showed that the degree of water penetration and topographic homogeneity of the biofilms was not influenced by sugar concentration. These results show that kefir biofilms have excellent structural and morphological properties to be used in the biomedical field.

The roméite-group is part of the pyrochlore-supergroup and comprises cubic oxides of A₂B₂X₆Y formula in which Sb⁵⁺ predominates in the B-site. The A and Y main occupants determine different minerals in the group and are important for the discovery of new mineral species. Two different roméite-group mineral samples were analysed by electron microprobe analysis (EMPA), Raman spectroscopy and single-crystal X-ray diffraction (XRD). The first sample is from Prabornaz Mine (locality of the original roméite), Saint Marcel, Valle d’Aosta, Italy, whereas the other one occurs in Kalugeri Hill, Babuna Valley, Jakupica Mountains, Nezilovo, Veles, Macedonia. Sample 1 was identified as fluorcalcioroméite, and sample 2 as hydroxycalcioroméite. Both samples belong to the cubic crystal system, space group Fd$\overline{3}$m, Z = 8, where a = 10.2881(13) Å, V = 1088.9(4) ų for sample 1, and a = 10.2970(13) Å, V = 1091.8(4) ų for sample 2. The crystal structure refinements converged to (1) R₁ = 0.016, wR₂ = 0.042; and (2) R₁ = 0.023, wR₂ = 0.049. Bond-valence calculations validated the crystal structure refinements determining the correct valences at each crystallographic site. Discrepancies observed in the Sb⁵⁺ bond-valence calculations were solved with the use of the proper bond valence parameters. The resulting structural formulas are (Ca_1.29Na_0.55□_0.11Pb_0.05)_Σ=2.00(Sb_1.71Ti_0.29)_Σ=2.00[O_5.73(OH)_0.27]_Σ=6.00[F_0.77O_0.21(OH)_0.02]_Σ=1.00 for sample 1, and (Ca_1.30Ce_0.51□_0.19)_Σ=2.00(Sb_1.08Ti_0.92)_Σ=2.00O_6.00[(OH)_0.61O_0.21F_0.18]_Σ=1.00 for sample 2. The Raman spectra of the samples exhibited the characteristic bands of roméite-group minerals, the most evident corresponding to the Sb-O stretching at around 510 cm⁻¹.

Este artigo analisa produções científicas nacionais sobre a aplicação da Plataforma PhET no ensino de Física, focando no engajamento e aprendizado dos alunos e no papel do professor como mediador. A pesquisa é do tipo bibliográfica e utilizou o Portal de Periódicos da CAPES (2014-2024), resultando em 14 artigos revisados por pares e publicados em revistas científicas. Os estudos indicam o uso da plataforma PhET nos processos de ensino e aprendizagem, tanto na formação de professores quanto em aplicações com estudantes do ensino médio, como tendência ao uso de metodologias ativas aliadas às simulações (Sims) da plataforma. Conclui-se que o emprego das Sims da plataforma PhET facilitam a compreensão de conceitos físicos que normalmente são difíceis de serem visualizados no cotidiano.