Digital Pregnancy Test Powered by an Air-Breathing Paper-Based Microfluidic Fuel Cell Stack Using Human Urine as Fuel.

The direct integration of paper-based microfluidic fuel cells (µFC's) toward creating autonomous lateral flow assays has attracted attention. Here, we show that an air-breathing paper-based µFC could be used as a power supply in pregnancy tests by oxidizing the human urine used for the diagnosis. We present an air-breathing paper-based µFC connected to a pregnancy test, and for the first time, as far as we know, it is powered by human urine without needing any external electrolyte. It uses TiO2-Ni as anode and Pt/C as cathode; the performance shows a maximum value of voltage and current and power densities of ∼0.96 V, 1.00 mA cm-2, and 0.23 mW cm-2, respectively. Furthermore, we present a simple design of a paper-based µFC's stack powered with urine that shows a maximum voltage and maximum current and power densities of ∼1.89 V, 2.77 mA cm-2 and 1.38 mW cm-2, respectively, which powers the display of a pregnancy test allowing to see the analysis results.

Comparison of the bioactive potential of Roselle (Hibiscus sabdariffa L.) calyx and its by-product: Phenolic characterization by UPLC-QTOF MSE and their anti-obesity effect in vivo.

The aim of the present study was to evaluate extractable (EPP), non-extractable polyphenols (NEPP) and organic acid in Roselle by-product, as well as its potential health beneficial effects in obesity control and their complication in rats fed with high caloric diet. Roselle by-product showed a higher content of dietary fiber and NEPP than Roselle calix, which was was a better source of EPP (P < .05). The UPLC-QTOF MSE analysis allowed the tentative identification of 34 EPP, and 3 hydrolysable polyphenols (NEPP), and 2 organic acids in calyx and by-product. Rats fed with a high caloric diet supplemented with 4% of dietary fiber from by-products and Roselle calyx powder generated a reduction in body weight gain (10% and 14%), adipocytes hypertrophy (17% and 13%) and insulin resistance (48% and 59%) and hepatic steatosis (15% and 25%; respectively) compared with rats fed with a high caloric diet alone. Interestingly, even though Roselle by-product has low EPP contents showed comparable beneficial health effects than Roselle calyces. These effects could be associated with high content of dietary fiber and NEPP. Together, the results of the present study indicate that Roselle by-products could be a potential ingredient to develop functional foods against obesity and its complications.

An integral profile of bioactive compounds and functional properties of prickly pear (Opuntia ficus indica L.) peel with different tonalities.

Prickly pear peel is an agroindustrial by-product source of dietary fiber and bioactive compounds. Three tonalities of prickly pear cultivars: Cristalina (green), Selección 2-1-62 (yellow-orange) and Roja Lisa (red) were evaluated regarding their bioactive compounds and functional, rheological, and morphological properties. Phytochemical profile assessed by UPLC-ESI-QTOF MSE allowed the identification of 145 compounds: sixty-eight extractable polyphenols, fifteen hydrolysable polyphenols, forty-one betalains, sixteen carotenoids, and five phytosterols. Cristalina showed the highest amount of extractable polyphenols (ferulic and benzoic acid, kaempferol 3-O-glucoside), Cristalina and Selección of hydrolysable polyphenols (gallic acid 3-O-gallate, cinnamic acid, hesperidin, myricetin 3-O-rhamnoside). Betaxanthins, carotenoids, and phytosterols were detected in all cultivars, mainly in Roja Lisa. All cultivars showed acceptable hydration properties, which was related to their porosity. Selección showed the highest elastic (G') and lower viscous (G″) behavior. These results suggest that prickly pear peels can be used as functional ingredients rich in bioactive compounds.