A Rapid Size-Exclusion Solid-Phase Extraction Step for Enhanced Sensitivity in Multi-Allergen Determination in Dark Chocolate and Biscuits by Liquid Chromatography–Tandem Mass Spectrometry

Enhanced sensitivity for the simultaneous determination of five nut allergens in biscuit and in dark chocolate complex matrices was obtained by introduction of a rapid size-exclusion solid-phase extraction-based step before liquid chromatography–electrospray ionization-tandem mass spectrometry (LC-ESI-MS²) analysis. A very fast and efficient separation (<12 min) of marker peptides with selected reaction monitoring detection was obtained. Limits of detection in the 0.1–1.3 mg nut/kg and 5–15 mg nut/kg ranges for biscuit and dark chocolate samples as well as high recoveries (84(±6)–106(±4)% for biscuits and 98(±5)–108(±6)% for dark chocolate) proved the excellent capabilities of the exploited sample treatment method combined with the LC-MS² analysis. Good precision in terms of intra- and inter-day repeatability was calculated, being always lower than 19 % (n?=?75). Linearity was demonstrated up to four and three orders of magnitude for biscuit and dark chocolate, respectively. Finally, the validated method was successfully applied to the investigation of hidden nut trace allergens in commercially available biscuits and chocolates of different brands aiming to ascertain possible discrepancies between allergen content and food allergen labelling.     

Extraction of phenolic compounds from Vitex agnus-castus L.

The primary objective of this study was to valorized Vitex agnus-castus residues in terms of phenolic compounds. The effects of extraction time (30–360 min), solid to liquid ratio (0.1–0.3 g_DryBiomass/ml_Solvent), type of solvent and different tissue types (leave, roots and seeds) on total polyphenols, o-diphenols, total flavonoids and anthocyanins were evaluated. The highest total polyphenol (31.5 mg_{CaffeicAcidEquivalent}/g_DryBiomass) and o-diphenol (12.4 mg_{CaffeicAcidEquivalent}/g_DryBiomass) contents were obtained from methanolic extract of leaves after 180 min using a solid/liquid ratio of 0.1 g_DryBiomass/ml_Solvent, while total flavonoids, reached a maximum value of 19.4 mg_{CatechinEquivalent}/g_DryBiomass after 360 min under the same conditions. Roots of V. agnus-castus were found to be a good source of anthocyanins with the highest yield of 0.62 mg_{MalvidinEquivalent}/g_DryBiomass using ethanol as a solvent (180 min and 0.2 g_DryBiomass/ml_Solvent). The maximum antiradical power (178.5 μl_extract/μg_DPPH) was exhibited by the methanolic leave extract obtained after 360 min at solid/liquid ratio of 0.3 g_DryBiomass/ml_Solvent.     

Compact multiplexing of monodisperse electrosprays

Widespread application of the cone-jet electrospray has been hampered by the low flow rate at which the spray is dispersed, despite the unique ability of this device to disperse quasi-monodispersed particles over a phenomenal size range. Compact multiplexing, that is, with a high number of sources per unit area, is indispensable for dramatically increasing the throughput and reducing the cost per electrospray source. We demonstrate the successful operation of multiplexed electrospray systems with an unprecedented packing density of up to 11,547 sources/cm². The devices were fabricated and operated by implementing three criteria: (a) the extractor electrode configuration should be used to localize the electric field; (b) the viscous pressure drop acting on the liquid should dominate with respect to the electrostatic pulling force by the electric field; and (c) the electric field “driving” the droplets between the extractor electrode and the collector should be sufficiently intense to avoid reversal of the droplet motion near the extractor (satellite trapping). All devices showed excellent droplet size uniformity across the entire spray region, which indicates effective decoupling of the electrospray sources even for closely packed nozzles. The experimental results show that these design criteria provide effective and reliable guidelines for the successful design and operation of multiplexed devices from first principles, that is, based only on knowledge of the suitability of a liquid for electrospray dispersion and of the critical liquid properties such as surface tension, viscosity and electric conductivity. As a result, the design of these devices for a given application is achievable without costly trial-and-error microfabrication trials. This development opens the door for applications requiring flows from multiplexing 10⁶–10⁷ individual electrospray sources from industry-standard 12-in silicon wafers.     

Glare‐limited appearances in HDR images

Abstract— Intraocular glare and simultaneous contrast control appearance in high‐dynamic‐range (HDR) images. This paper describes unique test targets that simulate real images. These targets change the HDR range by 500 times, without significantly changing the veiling glare on the retina. As well, these targets have nearly constant simultaneous contrast. The range of appearances possible from HDR images with different average luminances were measured. The targets displayed a maximum luminance range of 5.4 log units. Using magnitude estimates (MagEst) of appearances, the relationship between luminance and lightness from white to black was measured. With one exception, only small changes in appearance with large changes in dynamic range were found. It was also found that appearance was scene‐dependent. The same dark grays (MagEst = 10) were observed with luminances of 10, 4.2, 1.1, and 0.063, depending on the percentage of white area in the surround. Glare from more white increases the retinal luminance of the test areas. Simultaneous contrast counteracts glare by making the appearance range (white‐black) with a much smaller range of luminances. Appearance is controlled by both the optical scattered light and the spatial processing. A single tone‐scale function of luminance cannot describe appearance controlled by scatter and spatial processing.     

Ionic liquids as diathermic fluids for solar trough collectors’ technology: A corrosion study

The AISI 304 and AISI 1018 steels (frequently used in solar collectors’ plants) in contact with four different ionic liquids (ILs) suitable as diathermic fluids, were studied. Immersion tests were performed at 220 °C (the working temperature in such plants) for 10 days. The corrosion morphologies of the steels were investigated by scanning electron microscopy coupled with energy dispersive X-ray (EDX) microanalysis and the content of metals in the solution were detected via ICP-OES. The tests showed that the most performing IL is the ethyl-dimethyl-propyl-ammonium-bis(trifluoromethylsulphonyl)imide. The corrosion properties of the two alloys in contact with such IL were investigated by means of Tafel plots and resistance polarization at room temperature in open-to-air vessels.     

A New Approach for Firm Value and Default Probability Estimation beyond Merton Models

In this paper we present a new model to assess the firm value and the default probability by using a bivariate contingent claim analysis and copula theory. First we discuss an unfeasible case, given the current derivative market on corporate bonds, which involves univariate digital options to compute the risk neutral probabilities. We then discuss a feasible model, which considers risky interest rates, instead. Moreover, we develop in this framework a new methodology to extract default probabilities from stock prices, only, going beyond the standard KMV-Merton model. Besides, the non-observability of the Merton model’s state variable requires numerical methods, but the results can be unstable with noisy risky data. We show how the null price can be used as a useful barrier to separate an operative firm from a defaulted one, and to estimate its default probability. We then present an empirical application with both operative and defaulted firms to show the advantages of our approach.      

Spectral Green's Functions for Layered Gyrotropic Structures Through a Transmission-Line Approach

In this work, a straightforward method is shown to derive spectral Green's functions in classes of planar structures including gyrotropic media, based on a recently proposed transmission-line formalism. In particular, the analysis is expressly carried out for a current line source in layered configurations with transversely-magnetized ferrites, useful for microwave and millimeter-wave waveguiding and radiating devices.     

A model predictive control approach for the Italian LBE-XADS

In this paper, model predictive control (MPC) is applied to the Italian 80 MW_th experimental accelerator driven system (XADS), referring to a simple, non-linear model for the dynamic simulation of the plant, which has been developed and described in a previous work [A. Cammi, L. Luzzi, A.A. Porta, M.E. Ricotti, Prog. Nucl. Energ. 48 (2006) 578], in order to describe the interactions among the different subsystems: i.e., the accelerator-core coupling, the lead bismuth eutectic (LBE) primary system, the secondary system with diathermic oil and air coolers batteries, which reject the thermal power to the environment. Hereinafter, a model predictive controller is proposed, with the objective to minimize the difference between the average temperature of the diathermic oil and its reference value, while also minimizing the variations of the control input, which is the air coolers mass flow rate. The dynamic response of the LBE-XADS has been evaluated with reference to a reduction of 20% in the reactor power from nominal load conditions: this transient is very demanding for the overall plant, nevertheless the obtained results indicate the effectiveness of the proposed controller.