Gravimetry is a well-established technique for the determination of sub-surface mass distribution needed in several fields of geoscience, and various types of gravimeters have been developed over the last 50 years. Among them, quantum gravimeters based on atom interferometry have shown top-level performance in terms of sensitivity, long-term stability and accuracy. Nevertheless, they have remained confined to laboratories due to their complex operation and high sensitivity to the external environment. Here we report on a novel, transportable, quantum gravimeter that can be operated under real world conditions by non-specialists, and measure the absolute gravitational acceleration continuously with a long-term stability below 10 nm.s−2 (1 μGal). It features several technological innovations that allow for high-precision gravity measurements, while keeping the instrument light and small enough for field measurements. The instrument was characterized in detail and its stability was evaluated during a month-long measurement campaign.

SummaryPhotothermal microscopy enables detection of nanometersized objects solely based on their absorption. This technique allows efficient observation of various nano-objects in scattering media notably gold nanoparticles in cells. The extreme sensitivity of the method and the stability of the signals open numerous applications in spectroscopy, analytical chemistry and bioimaging. This review briefly describes the principle and the main characteristics of photothermal microscopy, with its major advantages and limitations, and exposes the principal applications that have been carried out since its first implementation.

Knowledge of the spatio-temporal changes in the characteristics and distribution of subsurface fluids is key to properly addressing important societal issues, including: sustainable management of energy resources (e.g., hydrocarbons and geothermal energy), management of water resources, and assessment of hazard (e.g., volcanic eruptions). Gravimetry is highly attractive because it can detect changes in subsurface mass, thus providing a window into processes that involve deep fluids. However, high cost and operating features associated with current instrumentation seriously limits the practical field use of this geophysical method. The NEWTON-g project proposes a radical change of paradigm for gravimetry through the development of a fieldcompatible measuring system (the gravity imager), able to real-time monitor the evolution of the subsurface mass changes. This system includes an array of lowcosts microelectromechanical systems-based relative gravimeters, anchored on an absolute quantum gravimeter. It will provide imaging of gravity changes, associated with variations in subsurface fluid properties, with unparalleled spatio-temporal resolution. During the final ∼2 years of NEWTON-g, the gravity imager will be field tested in the summit of Mt. Etna volcano (Italy), where frequent gravity fluctuations, easy access to the active structures and the presence of a multiparameter monitoring system (including traditional gravimeters) ensure an excellent natural laboratory for testing the new tools. Insights from the gravity imager will be used to i) improve our knowledge of the causeeffect relationships between volcanic processes and gravity changes observable at the surface and ii) develop strategies to best incorporate the gravity data into hazards assessments and mitigation plans. A successful implementation of NEWTON-g will open new doors for geophysical exploration.

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Abstract.We describe the implementation and use of an adaptive optics loop in the imaging path of a commercial wide field microscope. We show that it is possible to maintain the optical performances of the original microscope when imaging through aberrant biological samples. The sources used for illuminating the adaptive optics loop are spectrally independent, in excitation and emission, from the sample, so they do not appear in the final image, and their use does not contribute to the sample bleaching. Results are compared with equivalent images obtained with an identical microscope devoid of adaptive optics system. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

We propose a structured illumination microscopy method to combine super resolution and optical sectioning in three-dimensional (3D) samples that allows the use of two-dimensional (2D) data processing. Indeed, obtaining super-resolution images of thick samples is a difficult task if low spatial frequencies are present in the in-focus section of the sample, as these frequencies have to be distinguished from the out-of-focus background. A rigorous treatment would require a 3D reconstruction of the whole sample using a 3D point spread function and a 3D stack of structured illumination data. The number of raw images required, 15 per optical section in this case, limits the rate at which high-resolution images can be obtained. We show that by a succession of two different treatments of structured illumination data we can estimate the contrast of the illumination pattern and remove the out-of-focus content from the raw images. After this cleaning step, we can obtain super-resolution images of optical sections in thick samples using a two-beam harmonic illumination pattern and a limited number of raw images. This two-step processing makes it possible to obtain super resolved optical sections in thick samples as fast as if the sample was two-dimensional.

Background The purpose of this study was to evaluate potency changes in insulin in different solutions and bag materials used for peritoneal dialysis (PD). One of the PD solutions (Physioneal) tested is available in two different solution containers, PVC and Clear-Flex. Four insulin concentrations (4 IU/L, 10 IU/L, 20 IU/L, and 40 IU/L) were evaluated. This range of concentrations was defined in accordance with standard medical practice. All PD solutions made by Baxter, Castlebar, Ireland. Methods Insulin determination was performed by immunoassay (ELISA). Results In Dianeal, more than 90% of the initial dose of insulin remained available up to 24 hours for all concentrations tested. In Physioneal, for the higher concentrations tested (10 IU/L, 20 IU/L, and 40 IU/L), more than 90% of the initial dose of insulin remained available up to 6 hours, and more than 80% up to 24 hours. For the lowest concentration of insulin tested in Physioneal (4 IU/L), more than 90% of the initial dose of insulin remained available up to 3 hours, and more than 70% up to 24 hours. Also for the lowest concentration of insulin, recovery correlated with the pH of the tested solutions. This effect became apparent over the storage time. Conclusions The data show that insulin adsorption is less than 10% during the first 3 hours for every PD solution tested. Insulin recovery tends to be stable or to decrease slightly over time for the lower insulin concentrations tested. The results for insulin recovery show a correlation with insulin concentration and with pH for the lowest insulin dose tested. From a solution–container interaction perspective, Clear-Flex is an equivalent alternative to standard PVC material.

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