Ionogels based on a single ionic liquid for electronic nose application

165186/2015-1 307501/2019-1 424027/2018-6 grant reference SCENT-ERC-2014-STG-639123 (2015-2020) UIDB/04378/2020 POCI-01-0145-FEDER-007728Ionogel are versatile materials, as they present the electrical properties of ionic liquids and also dimensional stability, since they are trapped in a solid matrix, allowing application in electronic devices such as gas sensors and electronic noses. In this work, ionogels were designed to act as a sensitive layer for the detection of volatiles in a custom-made electronic nose. Ionogels composed of gelatin and a single imidazolium ionic liquid were doped with bare and functionalized iron oxide nanoparticles, producing ionogels with adjustable target selectivity. After exposing an array of four ionogels to 12 distinct volatile organic compounds, the collected signals were analyzed by principal component analysis (PCA) and by several supervised classification methods, in order to assess the ability of the electronic nose to distinguish different volatiles, which showed accuracy above 98%.publishersversionpublishe

Core-shell Fe@Fex_xOy_y nanoring system: A versatile platform for biomedical applications

Iron oxide (maghemite and magnetite) nanoparticles are the most commonly used magnetic materials in nanomedicine because of their high biocompatibility. However, their low saturation magnetization (60–90 emu/g) limits their applicability. Here, we report a new core–shell (Fe@Fe$_x$O$_y$) nanoring system, which combines the high magnetic saturation of a metallic iron core (220 emu/g) and the biocompatibility of an iron oxide shell. To produce these nanostructures, hematite (α-Fe$_2$O$_3$) nanorings were annealed in a H$_2$ gas atmosphere for different periods to optimize the amount of metallic iron percentage (δ) in the system. Thus, nanostructures with different magnetic saturation (97 to 178 emu/g) could be obtained; based on their metallic iron content, these particles are labeled as Vortex Iron oxide Particle δ (VIPδ). Micromagnetic simulations confirmed that the VIPδ nanorings exhibit a vortex configuration, guaranteeing low remanence and coercitivity. Moreover, the system shows good biocompatibility in various assays as determined through cell viability measurements performed using two different human cell lines, which were exposed to VIP78% for 24 h. Therefore, VIPδ nanorings combine a magnetic vortex state and biocompatibility with their high magnetic saturation and can thus serve as a platform that can be tuned during the synthesis based on desired biomedical application

Benefícios da Cafeína sobre os Níveis Séricos de Colesterol e Triglicerídeos

A cafeína (CF) é o ingrediente ativo do café e também de outros alimentos e medicamentos muito consumidos. Este estudo teve como objetivo avaliar o efeito da CF, em diferentes concentrações, sobre os valores séricos de colesterol total (CT) e frações, triglicerídeos (TG) e lipoproteínas HDL colesterol e VLDL colesterol em ratos. Foram analisadas 60 amostras de soro de ratos Wistar machos, submetidos à ingestão de solução aquosa de CF durante quatro dias, sendo sacrificados no quinto dia. As análises de CT e frações foram realizadas por equipamento automatizado (Technicon RA – XT) e os valores de VLDL colesterol, calculados pela equação de Friedewald. Os ratos submetidos ao tratamento com CF foram divididos em três grupos: a) grupo 1: 0,3 mg/ mL/100g peso; b) grupo 2: 6 mg/mL/100g peso; e c) grupo 3: 10 mg/mL/100g peso. Ao grupo controle não foi administrada CF. Foi observada uma diminuição altamente significativa (p<0,01) nos valores de CT dos ratos pertencentes aos grupos 2 e 3 em relação aos do grupo controle; detectou-se uma diminuição altamente significativa (p<0,01) nos valores de TG e VLDL colesterol dos ratos pertencentes ao grupo 3 quando comparados aos do grupo controle; verificou-se também uma diminuição altamente significativa (p<0,01) nos valores de HDL colesterol dos ratos pertencentes ao grupo 2 quando comparados aos do grupo controle. Foi demonstrado também um efeito dose-dependente nos grupos tratados com CF. Estudos epidemiológicos demonstram que o consumo de café fervido e não filtrado eleva o risco de doenças cardiovasculares, devido à presença de dois diterpenos, que promovem o aumento da concentração plasmática de colesterol em seres humanos. Entretanto, outros estudos mostram que o consumo de substâncias ricas em CF leva à diminuição de CT. Nosso trabalho demonstrou que a cafeína pura levou à diminuição de CT, TG e VLDL colesterol, sugerindo um efeito benéfico da CF no sistema cardiovascular, principalmente quando associada aos antioxidantes presentes no café. No entanto, em razão da diminuição nos níveis de HDL colesterol, serão necessários estudos complementares para esclarecer seu exato papel no organismo e na prevenção da placa de ateroma.A cafeína (CF) é o ingrediente ativo do café e também de outros alimentos e medicamentos muito consumidos. Este estudo teve como objetivo avaliar o efeito da CF, em diferentes concentrações, sobre os valores séricos de colesterol total (CT) e frações, triglicerídeos (TG) e lipoproteínas HDL colesterol e VLDL colesterol em ratos. Foram analisadas 60 amostras de soro de ratos Wistar machos, submetidos à ingestão de solução aquosa de CF durante quatro dias, sendo sacrificados no quinto dia. As análises de CT e frações foram realizadas por equipamento automatizado (Technicon RA – XT) e os valores de VLDL colesterol, calculados pela equação de Friedewald. Os ratos submetidos ao tratamento com CF foram divididos em três grupos: a) grupo 1: 0,3 mg/ mL/100g peso; b) grupo 2: 6 mg/mL/100g peso; e c) grupo 3: 10 mg/mL/100g peso. Ao grupo controle não foi administrada CF. Foi observada uma diminuição altamente significativa (p<0,01) nos valores de CT dos ratos pertencentes aos grupos 2 e 3 em relação aos do grupo controle; detectou-se uma diminuição altamente significativa (p<0,01) nos valores de TG e VLDL colesterol dos ratos pertencentes ao grupo 3 quando comparados aos do grupo controle; verificou-se também uma diminuição altamente significativa (p<0,01) nos valores de HDL colesterol dos ratos pertencentes ao grupo 2 quando comparados aos do grupo controle. Foi demonstrado também um efeito dose-dependente nos grupos tratados com CF. Estudos epidemiológicos demonstram que o consumo de café fervido e não filtrado eleva o risco de doenças cardiovasculares, devido à presença de dois diterpenos, que promovem o aumento da concentração plasmática de colesterol em seres humanos. Entretanto, outros estudos mostram que o consumo de substâncias ricas em CF leva à diminuição de CT. Nosso trabalho demonstrou que a cafeína pura levou à diminuição de CT, TG e VLDL colesterol, sugerindo um efeito benéfico da CF no sistema cardiovascular, principalmente quando associada aos antioxidantes presentes no café. No entanto, em razão da diminuição nos níveis de HDL colesterol, serão necessários estudos complementares para esclarecer seu exato papel no organismo e na prevenção da placa de ateroma

A STUDY ABOUT CELL ACTIVITY ON ANODIZED Ti-6Al-4V BY MEANS OF PULSED CURRENT

Titanium and some of its alloys exhibit excellent anti-corrosive and biocompatibility properties due to rapid formation of a passive film on their surfaces when exposed to the atmosphere. However, such materials presentpoor osteoindutive properties. Surfaces modified via anodization are being proposed in this study to promote a chemical interaction between implants and bone cells. For this purpose, samples in Ti-6Al-4V alloy discs were anodized in a phosphoric acid solution using pulsed current for being applied in orthopaedic implants. The pulsed current is based on duty cycle (DC), which was supplied by a square wave pulse rectifier at 100 Hz and maximum tension of 30 V. A scanning electron microscope was used to obtain images of the anodized surfaces, thus revealing the presence of uniformly distributed pores over the entire surface, measuring approximately 2 m in diameter. Osteogenic cells grown on the surface of the control and anodized samples were assayed for cytotoxicity and mineralized matrix formation. The anodized surfaces presented a higher rate of viable cells after 10 days, as well as a higher amount of nodules (p = 0.05). In conclusion, these results suggest that the nanotopography promoted by anodization using pulsed current induces beneficial modulatory effects on osteoblastic cells

The conservation status of the world's freshwater molluscs

With the biodiversity crisis continuing unchecked, we need to establish levels and drivers of extinction risk, and reassessments over time, to effectively allocate conservation resources and track progress towards global conservation targets. Given that threat appears particularly high in freshwaters, we assessed the extinction risk of 1428 randomly selected freshwater molluscs using the IUCN Red List Categories and Criteria, as part of the Sampled Red List Index project. We show that close to one-third of species in our sample are estimated to be threatened with extinction, with highest levels of threat in the Nearctic, Palearctic and Australasia and among gastropods. Threat levels were higher in lotic than lentic systems. Pollution (chemical and physical) and the modification of natural systems (e.g. through damming and water abstraction) were the most frequently reported threats to freshwater molluscs, with some regional variation. Given that we found little spatial congruence between species richness patterns of freshwater molluscs and other freshwater taxa, apart from crayfish, new additional conservation priority areas emerged from our study. We discuss the implications of our findings for freshwater mollusc conservation, the adequacy of a sampled approach and important next steps to estimate trends in freshwater mollusc extinction risk over time

Moving in the anthropocene: global reductions in terrestrial mammalian movements

Animal movement is fundamental for ecosystem functioning and species survival, yet the effects of the anthropogenic footprint on animal movements have not been estimated across species. Using a unique GPS-tracking database of 803 individuals across 57 species, we found that movements of mammals in areas with a comparatively high human footprint were on average one-half to one-third the extent of their movements in areas with a low human footprint. We attribute this reduction to behavioral changes of individual animals and to the exclusion of species with long-range movements from areas with higher human impact. Global loss of vagility alters a key ecological trait of animals that affects not only population persistence but also ecosystem processes such as predator-prey interactions, nutrient cycling, and disease transmission