Characterization of Gold Nanorods Conjugated with Synthetic Glycopolymers Using an Analytical Approach Based on spICP-SFMS and EAF4-MALS

A new comprehensive analytical approach based on single-particle inductively coupled plasma-sector field mass spectrometry (spICP-SFMS) and electrical asymmetric-flow field-flow-fractionation combined with multi-angle light scattering detection (EAF4-MALS) has been examined for the characterization of galactosamine-terminated poly(N-hydroxyethyl acrylamide)-coated gold nanorods (GNRs) in two different degrees of polymerization (DP) by tuning the feed ratio (short: DP 35; long: DP 60). spICP-SFMS provided information on the particle number concentration, size and size distribution of the GNRs, and was found to be useful as an orthogonal method for fast characterization of GNRs. Glycoconjugated GNRs were separated and characterized via EAF4-MALS in terms of their size and charge and compared to the bare GNRs. In contrast to spICP-SFMS, EAF4-MALS was also able of providing an estimate of the thickness of the glycopolymer coating on the GNRs surface.

Polar Quasinormal Modes of Neutron Stars in Massive Scalar-Tensor Theories

We study polar quasinormal modes of relativistic stars in scalar-tensor theories, where we include a massive gravitational scalar field and employ the standard Brans-Dicke coupling function. For the potential of the scalar field we consider a simple mass term as well as a potential associated with R2 gravity. The presence of the scalar field makes the spectrum of quasinormal modes much richer than the spectrum in General Relativity. We here investigate radial modes (l = 0) and quadrupole modes (l = 2). The general relativistic l = 0 normal modes turn into quasinormal modes in scalar-tensor theories, that are able to propagate outside of the stars. In addition to the pressure-led modes new scalar-led ϕ-modes arise. We analyze the dependence of the quasinormal mode frequencies and decay times on the scalar field mass.

Development, Validation and Application of an ICP-SFMS Method for the Determination of Metals in Protein Powder Samples, Sourced in Ireland, with Risk Assessment for Irish Consumers

A method has been developed, optimised and validated to analyse protein powder supplements on an inductively coupled plasma-sector field mass spectrometer (ICP-SFMS), with reference to ICH Guideline Q2 Validation of Analytical Procedures: Text and Methodology. This method was used in the assessment of twenty-one (n = 21) elements (Al, Au, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Pb, Pt, Sn, Ti, Tl, V) to evaluate the safety of thirty-six (n = 36) protein powder samples that were commercially available in the Irish marketplace in 2016/2017. Using the determined concentrations of elements in samples (µg·kg−1), a human health risk assessment was carried out to evaluate the potential carcinogenic and other risks to consumers of these products. While the concentrations of potentially toxic elements were found to be at acceptable levels, the results suggest that excessive and prolonged use of some of these products may place consumers at a slightly elevated risk for developing cancer or other negative health impacts throughout their lifetimes. Thus, the excessive use of these products is to be cautioned, and consumers are encouraged to follow manufacturer serving recommendations.

Solar Field Output Temperature Optimization Using a MILP Algorithm and a 0D Model in the Case of a Hybrid Concentrated Solar Thermal Power Plant for SHIP Applications

Using solar power for industrial process heat is an increasing trend to fight against climate change thanks to renewable heat. Process heat demand and solar flux can both present intermittency issues in industrial systems, therefore solar systems with storage introduce a degree of freedom on which optimization, on a mathematical basis, can be performed. As the efficiency of solar thermal receivers varies as a function of temperature and solar flux, it seems natural to consider an optimization on the operating temperature of the solar field. In this paper, a Mixed Integer Linear Programming (MILP) algorithm is developed to optimize the operating temperature in a system consisting of a concentrated solar thermal field with storage, hybridized with a boiler. The MILP algorithm optimizes the control trajectory on a time horizon of 48 h in order to minimize boiler use. Objective function corresponds to the boiler use, for completion of the heat from the solar field, whereas the linear constraints are a simplified representation of the system. The solar field mass flow rate is the optimization variable which is directly linked to the outlet temperature of the solar field. The control trajectory consists of the solar field mass flow rate and outlet temperature, along with the auxiliary mass flow rate going directly to the boiler. The control trajectory is then injected in a 0D model of the plant which performs more detailed calculations. For the purpose of the study, a Linear Fresnel system is investigated, with generic heat demand curves and constant temperature demand. The value of the developed algorithm is compared with two other control approaches: one operating at the nominal solar field output temperature, and the other one operating at the actual demand mass flow rate. Finally, a case study and a sensitivity analysis are presented. The MILP’s control shows to be more performant, up to a relative increase of the annual solar fraction of 4% at 350 °C process temperature. Novelty of this work resides in the MILP optimization of temperature levels presenting high non-linearities, applied to a solar thermal system with storage for process heat applications.

Massive scalar field perturbation on Kerr black holes in dynamical Chern–Simons gravity

We study massive scalar field perturbation on Kerr black holes in dynamical Chern–Simons gravity by performing a $$(2+1)$$ ( 2 + 1 ) -dimensional simulation. Object pictures of the wave dynamics in time domain are obtained. The tachyonic instability is found to always occur for any nonzero black hole spin and any scalar field mass as long as the coupling constant exceeds a critical value. The presence of the mass term suppresses or even quench the instability. The quantitative dependence of the onset of the tachyonic instability on the coupling constant, the scalar field mass and the black hole spin is given numerically.

On quantum corrections to geodesics in de-Sitter spacetime

We find a coordinate-independent wave-packet solution of the massive Klein–Gordon equation with the conformal coupling to gravity in the de-Sitter universe. This solution can locally be represented through the superposition of positive-frequency plane waves at any space-time point, assuming that the scalar-field mass M is much bigger than the de-Sitter Hubble constant H. The solution is also shown to be related to the two-point function in the de-Sitter quantum vacuum. Moreover, we study the wave-packet propagation over cosmological times, depending on the ratio of M and H. In doing so, we find that this wave packet propagates like a point-like particle of the same mass if $$M \ggg H$$ M ⋙ H , but, if otherwise, the wave packet behaves highly non-classically.

NATURAL RADIONUCLIDES IN WATER USING INDUCTIVELY COUPLED PLASMA - SECTOR FIELD MASS SPECTROMETRY

Simultaneous analysis of radionuclides in water had not been performed by mass spectrometry of the magnetic sector. Some international organizations indicate that it is necessary to know the contamination of drinking-water, including radioactive aspects. The novelty of this study was to determine simultaneously radioisotope radium, thorium, uranium and lead stable. Experiments were performed in an accredited laboratory (International Organization for Standardization/International Electrotechnical Commission-7025:2005). The radionuclides of thorium, uranium and some of their descendants were obtained. The reported values are in the range of 7E-7-24.28 µg L-1. Their presence decreases in the order thorium>uranium>radium in drinking water and uranium>thorium>radium in seawater. These results do not represent any risk to the population because very low concentrations were determined.