Source terms for benchmarking models of SARS-CoV-2 transmission via aerosols and droplets.

There is ongoing and rapid advancement in approaches to modelling the fate of exhaled particles in different environments relevant to disease transmission. It is important that models are verified by comparison with each other using a common set of input parameters to ensure that model differences can be interpreted in terms of model physics rather than unspecified differences in model input parameters. In this paper, we define parameters necessary for such benchmarking of models of airborne particles exhaled by humans and transported in the environment during breathing and speaking

Freezing or wrapping: the role of particle size in the mechanism of nanoparticle-biomembrane interaction.

Understanding the interactions between nanoparticles (NPs) and biological matter is a high-priority research area because of the importance of elucidating the physical mechanisms underlying the interactions leading to NP potential toxicity as well as NP viability as therapeutic vectors in nanomedicine. Here, we use two model membrane systems, giant unilamellar vesicles (GUVs) and supported monolayers, to demonstrate the competition between adhesion and elastic energy at the nanobio interface, leading to different mechanisms of NP-membrane interaction relating to NP size. Small NPs (18 nm) cause a "freeze effect" of otherwise fluid phospholipids, significantly decreasing the phospholipid lateral mobility. The release of tension through stress-induced fracture mechanics results in a single microsize hole in the GUVs after interaction. Large particles (>78 nm) promote membrane wrapping, which leads to increased lipid lateral mobility and the eventual collapse of the vesicles. Electrochemical impedance spectroscopy on the supported monolayer model confirms that differently sized NPs interact differently with the phospholipids in close proximity to the electrode during the lipid desorption process. The time scale of these processes is in accordance with the proposed NP/GUV interaction mechanism

Constrained Multicriteria Sorting Method Applied to Portfolio Selection

The paper focuses on portfolio selection problems which aim at selecting a subset of alternatives considering not only the performance of the alternatives evaluated on multiple criteria, but also the performance of portfolio as a whole, on which balance over alternatives on specific attributes is required by the Decision Makers (DMs). We propose a two-level method to handle such decision situation. First, at the individual level, the alternatives are evaluated by the sorting model Electre Tri which assigns alternatives to predefined ordered categories by comparing alternatives to profiles separating the categories. The DMs' preferences on alternatives are expressed by some assignment examples they can provide, which reduces the DMs' cognitive efforts. Second, at the portfolio level, the DMs' preferences express requirements on the composition of portfolio and are modeled as constraints on category size. The method proceeds through the resolution of a Mixed Integer Program (MIP) and selects a satisfactory portfolio as close as possible to the DMs' preference. The usefulness of the proposed method is illustrated by an example which integrates a sorting model with assignment examples and constraints on the portfolio definition. The method can be used widely in portfolio selection situation where the decision should be made taking into account the performances of individual alternatives and portfolio simultaneousl

British trade unions and European Union integration in the 1990s: politics versus political economy

This article evaluates the changing assessments within the British trade union movement of the efficacy of European Union integration from the viewpoint of labour interests. It argues that there has been a marked further ‘Europeanisation’ of British trade unionism during the 1990s, consolidating an on-going process which previous research shows began in earnest in the mid 1980s. A shift in trade union economic policy assessments has seen the decisive abandonment of the previously dominant ‘naive’ or national Keynesianism. While there remain important differences in economic perspective between unions, these are not such as would create significant divisions over the question of European integration per se, the net benefits of which are now generally, though perhaps not universally, accepted. The absence of fundamental divisions is evident from a careful assessment of the debates about economic and monetary union at TUC Congress. The Europeanisation of British trade unionism needs to be seen within the context of an emergent regionalism, in Europe and elsewhere. It can best be understood as a rational response by an important corporate actor (albeit one whose national influence has been considerably diminished in recent decades) to globalisation and a significantly changing political economy environment

Direct characterisation of fluid lipid assemblies on mercury in electric fields

Phospholipid monolayers on mercury (Hg) surfaces have received substantial and extensive scientific interest not only because of their use as a biomembrane model but also for their application as a successful toxicity-sensing element. The monolayers show characteristic and very reproducible phase transitions manifest as consecutive voltammetric peaks in response to applied transverse electric fields. Unfortunately, apart from the results of simulation studies, there is a lack of data on the lipid phase structures to help interpret these voltammetric peaks. In this paper we report on the direct measurement of the structural changes underlying the phase transitions of phospholipid layers of dioleoyl phosphatidylcholine (DOPC) at electrified Hg surfaces using atomic force microscopy force–distance techniques. These direct measurements enable a description of the following structural changes in fluid lipid assemblies on a liquid electrode within an increasing transverse electric field. At about −1.0 V (vs Ag/AgCl) a field-facilitated ingress of ions and water into the monolayer results in a phase transition to a structured 2D emulsion. This is followed by a further phase transition at more negative potentials involving the readsorption of bilayer patches. At stronger values of field the bilayer patches form semivesicles, which subsequently collapse to form a monolayer of uncertain composition at very negative potentials. The observation that a monolayer on Hg converts to a bilayer by increasing the applied potential has allowed techniques to be developed for preparing and characterizing a near-continuous DOPC bilayer on Hg in an applied potential window within −1.0 and −1.4 V (vs Ag/AgCl)