Majority voting leads to unanimity

We consider a situation where society decides, through majority voting in a secret ballot, between the alternatives of ‘reform’ and ‘status quo’. Reform is assumed to create a minority of winners, while being efficient in the Kaldor–Hicks sense. We explore the consequences of allowing binding transfers between voters conditional on the chosen alternative. In particular, we establish conditions under which the winners wish to compensate all losers, thus leading to unanimity for reform, rather than compensating some losers to form a non-maximal majority. The analysis employs concepts from cooperative game theory.      

Adsorption of phenol and benzyl alcohol onto surfactant modified silica

The adsorption of the surfactant, dodecyltrimethylammonium bromide, DTAB, and the co-adsorption of the additives phenol and benzyl alcohol, onto silica from aqueous solutions are investigated. The adsorption of DTAB is found to increase with increasing alcohol concentration in solutions where the DTAB concentration is below the cmc. Moreover, the corresponding adsorption of DTAB decreases when the DTAB concentration is above the cmc. The co-adsorption of the alcohol is found to increase with increasing alcohol concentration, and benzyl alcohol co-adsorbs more strongly than phenol. The surfactant modified silica shows a very high ability to incorporate phenol and benzyl alcohol. The results are discussed in relation to solubilization site and surfactant aggregate shape.     

Modeling of micromachined silicon–polymer 2-2 composite matching layers for 15 MHz ultrasound transducers

Silicon–polymer composites fabricated by micromachining technology offer attractive properties for use as matching layers in high frequency ultrasound transducers. Understanding of the acoustic behavior of such composites is essential for using them as one of the layers in a multilayered transducer structure. This paper presents analytical and finite element models of the acoustic properties of silicon–polymer composites in 2-2 connectivity. Analytical calculations based on partial wave solutions are applied to identify the resonance modes and estimate effective acoustic material properties. Finite Element Method (FEM) simulations were used to investigate the interaction between the composite and the surrounding load medium, either a fluid or a solid, with emphasis on the acoustic impedance of the composite. Composites with lateral periods of 20, 40 and 80 μm were fabricated and used as acoustic matching layers for air-backed transducers operating at 15 MHz. These composites were characterized acoustically, and the results were compared with analytical calculations. The analytical model shows that at low to medium silicon volume fraction, the first lateral resonance in the silicon–polymer 2-2 composite is defined by the composite period, and this lateral resonant frequency is at least 1.2 times higher than that of a piezo-composite with the same polymer filler. FEM simulations showed that the effective acoustic impedance of the silicon–polymer composite varies with frequency, and that it also depends on the load material, especially whether this is a fluid or a solid. The estimated longitudinal sound velocities of the 20 and 40 μm period composites match the results from analytical calculations within 2.7% and 2.6%, respectively. The effective acoustic impedances of the 20 and 40 μm period composites were found to be 10% and 26% lower than the values from the analytical calculations. This difference is explained by the shear stiffness in the solid, which tends to even out the surface displacements of the composites.     

Two-dimensional LC-MS fractioning and cross-matching of mass spectrometric data for rational identification of bioactive compounds in crude extracts

Bioprospecting aims at the identification of biological compounds with novel properties. Identification of such compounds in crude complex biological extracts is a comprehensive challenge. As a large number of extracts must be screened for successful identification of one potential promising lead, rational screening strategies must be developed. Here we report on a novel two stage rational LC-MS strategy of extracts already pre-screened and proven to contain bioactive compound(s). All extracts are initially fractionated using one and the same LC condition with parallel mass spectrometric detection. Fractions containing bioactive compound(s) are then subjected to a second fractional stage using two different chromatographic conditions. Mass detection is also included at this stage, and a cross-matching algorithm for comparison of processed mass chromatograms from the two dimensions was developed. The algorithm reports only masses present in bioactive fractions in both dimensions and enable therefore an efficient identification of potential masses that causes the bioactivity. This mass list can be used to search in natural compound database(s) for a rapid evaluation if the mass belongs to an already identified compound or if it is a potentially new one. This strategy enables thorough screening of several hundred crude extracts in one week on one single instrument.     

Negishi Cross-Coupling in the Preparation of Benzyl Substituted Pyrrolo[2,3-d]pyrimidine Based CSF1R Inhibitors

The colony-stimulating factor 1 receptor (CSF1R) is a protein kinase emerging as an attractive target with clinical relevance in cancer, CNS and inflammatory diseases. Molecular docking experiments followed by synthesis and structure–activity relationship have been used to identify low molecular weight structures as promising hits for lead optimization. These molecules are synthesized from a 4-chloro-6-iodo-pyrrolo[2,3-d]pyrimidine building block using Negishi and Suzuki–Miyaura cross-coupling reactions in high yields. Several inhibitors possessed excellent enzymatic potency, and the parent compound preferably binds to the autoinhibited form of CSF1R. Cellular and in vivo profiling indicate that further tuning of drug structure is needed prior to efficacy studies.