Electron pumps capable of delivering a current higher than 100 pA with sufficient accuracy are likely to become the direct mise en pratique of the possible new quantum definition of the ampere. We present here single-island hybrid metal-semiconductor transistor pumps that combine the simplicity and efficiency of Coulomb blockade in metals with the unsurpassed performances of silicon switches. Robust and simple pumping at 650 MHz and 0.5 K is demonstrated. The pumped current obtained over a voltage-bias range of 1.4 mV corresponds to a relative deviation of 5 Â 10 À4 from the calculated value, well within the 1:5 Â 10 À3 uncertainty of the measurement setup. Multicharge pumping can be performed. The simple design that is fully integrated into an industrial microelectronics process makes it an ideal candidate for national measurement institutes to realize and share a future quantum ampere.

Background Titanium dioxide (TiO2) is broadly used in common consumer goods, including as a food additive (E171 in Europe) for colouring and opacifying properties. The E171 additive contains TiO2 nanoparticles (NPs), part of them being absorbed in the intestine and accumulated in several systemic organs. Exposure to TiO2-NPs in rodents during pregnancy resulted in alteration of placental functions and a materno-foetal transfer of NPs, both with toxic effects on the foetus. However, no human data are available for pregnant women exposed to food-grade TiO2-NPs and their potential transfer to the foetus. In this study, human placentae collected at term from normal pregnancies and meconium (the first stool of newborns) from unpaired mothers/children were analysed using inductively coupled plasma mass spectrometry (ICP-MS) and scanning transmission electron microscopy (STEM) coupled to energy-dispersive X-ray (EDX) spectroscopy for their titanium (Ti) contents and for analysis of TiO2 particle deposition, respectively. Using an ex vivo placenta perfusion model, we also assessed the transplacental passage of food-grade TiO2 particles. Results By ICP-MS analysis, we evidenced the presence of Ti in all placentae (basal level ranging from 0.01 to 0.48 mg/kg of tissue) and in 50% of the meconium samples (0.02–1.50 mg/kg), suggesting a materno-foetal passage of Ti. STEM-EDX observation of the placental tissues confirmed the presence of TiO2-NPs in addition to iron (Fe), tin (Sn), aluminium (Al) and silicon (Si) as mixed or isolated particle deposits. TiO2 particles, as well as Si, Al, Fe and zinc (Zn) particles were also recovered in the meconium. In placenta perfusion experiments, confocal imaging and SEM-EDX analysis of foetal exudate confirmed a low transfer of food-grade TiO2 particles to the foetal side, which was barely quantifiable by ICP-MS. Diameter measurements showed that 70 to 100% of the TiO2 particles recovered in the foetal exudate were nanosized. Conclusions Altogether, these results show a materno-foetal transfer of TiO2 particles during pregnancy, with food-grade TiO2 as a potential source for foetal exposure to NPs. These data emphasize the need for risk assessment of chronic exposure to TiO2-NPs during pregnancy.

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The advent of the fundamental constants R K (the von Klitzing constant) and K J (the Josephson constant) in electrical metrology and the growing development of nanotechnologies have totally changed the vision and the practice of the National Metrology Institutes (NMIs), opening a modern era of metrology and arousing a growing interest in a possible re-definition of the international system of units (SI). The Josephson effect (JE) and the Quantum Hall effect (QHE), at the origin of these fundamental constants, constitute the keystone of a new approach to electrical units, when one considers the very high level of reproducibility of these units, never seen before. On the other hand, the Watt balance experiment in which these constants play a part could be the origin of a new SI definition, replacing the mass unit 'the kilogram' as a fundamental unit by the Planck constant h. It thus seems that the implementation of experiments aimed at demonstrating the coherency between the theoretical and phenomenological values of these constants is a major objective. In this framework the metrological triangle experiment associating QHE, JE and single electron tunnelling effect would play a major role in checking the consistency of these fundamental constants in terms of the Planck and electron charge constants. This article gives briefly an outline of these quantum phenomena and their metrological applications in NMIs for the realisation of electrical units and the determination of the fundamental constants. To cite this article: F.

Instrument for high resolution magnetization measurements at high pressures, high magnetic fields and low temperatures Rev.We describe a versatile modular device built to generate forces up to 25 kN at cryogenic temperatures in order to achieve very fine in situ hydrostatic pressure tuning in the range 0-21 GPa. This device was designed to save time during measurements and protect the experimental setup by avoiding warming and cooling cycles to vary the pressure. The force is generated by a bellow operated with pressurized 4 He and amplified mechanically. Diamond and sapphire anvil cells are used to perform electrical resistivity, magnetic susceptibility, and specific heat measurements under highly hydrostatic conditions by using helium as the transmitting medium. The pressure is determined by the ruby fluorescence technique. The performance of the device is illustrated by measurements of the superconducting transition of Pb and the magnetic transitions of CeRu 2 Ge 2 in the range 0-10 GPa. This device is currently being adapted in a dilution fridge in order to be operated down to 50 mK.