Bioimpedance sensor to detect water content in milk based on van Der Pauw method.

Milk fraud poses serious problems for the dairy industry and consumers' health. The main aim of this study was to reveal the effect of water added to milk by measuring its electrical impedance spectrum. The required sensor was designed based on the van der Pauw method to measure the electrical conductivity of milk at the frequency band of 10 Hz to 5 MHz. The bioimpedance spectrum of the milk of five different cows showed that the electrical impedance spectrum has a high potential for detecting water added to the milk (P < 0.01). The area under the Nyquist curve was introduced as a suitable index to detect water-added milk. In addition, the characteristic frequency of the bioimpedance spectrum was used as an important index to differentiate water-added milk from waterless milk. An electrical model was introduced to interpret the amount of water added to the milk using the characteristic frequency. Results showed that it is possible to detect raw milk from boiled milk by measuring its electrical impedance.

Fe3O4 magnetic nanoparticles improve the vitrification of mouse immature oocytes and modulate the pluripotent genes expression in derived pronuclear-stage embryos.

The vitrification of Germinal Vesicle (immature) oocytes is beneficial for preservation of fertility in cases involving reproductive problems. The use of nanoparticles (NP(s)) as vitrification aid is a novel approach towards improving vitrification efficiency. The efficacy of use of iron oxide (Fe3O4) nanoparticles as vitrification aid is reported in this paper. Immature oocytes from NMRI mice were collected and divided into non-vitrified (nVit), Vitrified (Vit) and Vitrified + NP (Vit+NP) groups. In the Vit+NP group, solutions containing Fe3O4 nanoparticles at three different concentrations (0.004%, 0.008% and 0.016% w/v) were separately added to the vitrification solution and their effects on the vitrification of the oocytes were compared. The concentration that was found to be best performing (0.004% w/v) was used in vitrification studies in subsequent experiments. Mitochondrial function, apoptosis incidence, ultrastructure alteration, nuclear maturity, embryo formation and genes expression (Nanog, Oct4, Cdx2, and Sox2) were evaluated in response to the addition of the nanoparticle solution during vitrification. Nuclear maturity of oocyte and embryo formation increased significantly (P ≤ 0.05) in the vitrified + NP group. Expression of Sox2 also increased significantly in both vitrified and vitrified + NP groups. While there was a significant increase in Oct4 expression in the vitrified group as compared to control, there was no significant difference between vitrified and Vit+NP groups. The expression of Cdx2 decreased significantly (P ≤ 0.05) in the Vit+NP group. From these observations, Fe3O4 nanoparticles could protect immature oocytes from cryodamages, positively affect vitrification and modulate the pluripotency of derived pronuclear-stage embryos.