Nitroxide‐Mediated Aqueous Dispersion Polymerization: From Water‐Soluble Macroalkoxyamine to Thermosensitive Nanogels

Self‐stabilized nanoparticles with a temperature‐responsive poly[(N,N‐diethylacrylamide)‐co‐(N,N′‐methylenebisacrylamide)] microgel core and a covalently attached hairy shell were synthesized via a simple nitroxide‐mediated controlled free‐radical aqueous dispersion polymerization, using a poly(sodium acrylate) alkoxyamine macroinitiator. With this method, high solid content, surfactant‐free particle suspensions were prepared, with diameter ranging from 49 to 118 nm at high temperature, and able to reversibly swell with water at low temperature. The proposed method requires a limited number of reagents in a simple polymerization procedure and thus avoids many drawbacks generally encountered in the synthesis of thermally responsive microgel particles.

     

Structural analysis of pyrrolidinones

In the course of a study on pyrrolidinones, the crystal structures of four compounds, namely, methyl N‐[(4‐meth­oxy­phenyl)(3,4,5‐tri­meth­oxy­phenyl)­methyl]­pyro­glut­amate, C₂₃­H₂₇­NO₇, methyl N‐[naphthyl‐(3,4,5‐tri­meth­oxy­phenyl)­methyl]­pyro­glut­amate diacetyl peroxide, C₂₆­H₂₇­NO₆·‐0.5C₄H₆O₄, 5‐(3,4,5‐tri­meth­oxy­phenyl)‐1,2,3,11b‐tetrahy­dro‐5H‐naphtho­[1,8‐f,g]indol­izin‐3‐one, C₂₄­H₂₃­NO₄, and 5‐(3,4,5‐tri­meth­oxy­phenyl)‐1,2,3,5,12,12a‐hexa­hydro­naph­tho­[1,2‐f]indol­izine‐3,12‐dione, C₂₅­H₂₃­NO₅, are presented, compared and discussed.     

Hoogianal,a β‐Irone Precursor from Iris hoogiana Dykes (Iridaceae)

Fractionation of the lipid extract from rhizomes of Iris hoogiana Dykes resulted in the isolation of one new and several known iridals. The latter were identified by comparison with authentic standards as 1 – 5 . The structure of the new natural product, hoogianal ( 11 ), was elucidated by spectroscopic analysis. Oxidative degradation yielded β‐irone ( 10 ), identified by GC‐ and LC‐MS. The (−)‐(2S)‐configuration of this oxidation product was determined by enantioselective GC on a chiral cyclodextrin phase and by comparison with the corresponding ketones in laevo‐ and dextrorotatory commercial Iris oils.     

Recent developments in the design of functionalised polymeric microspheres

This paper is a brief survey on the preparation of latexes bearing covalently bonded functional groups using various routes. Recent methods are presented using water soluble functional (or surface active) initiators, monomers or macromonomers. For tailor synthesis, the copolymerisation approach of a basic monomer with a functional monomer under emulsifier-free conditions is generally the more suitable and versatile one. More progress should be pursued in this field in order to design better adapted chemical structures which will improve their use in radical-initiated heterogeneous conditions and favour surface incorporation.     

Data-driven discovery of cardiolipin-selective small molecules by computational active learning

Subtle variations in the lipid composition of mitochondrial membranes can have a profound impact on mitochondrial function. The inner mitochondrial membrane contains the phospholipid cardiolipin, which has been demonstrated to act as a biomarker for a number of diverse pathologies. Small molecule dyes capable of selectively partitioning into cardiolipin membranes enable visualization and quantification of the cardiolipin content. Here we present a data-driven approach that combines a deep learning-enabled active learning workflow with coarse-grained molecular dynamics simulations and alchemical free energy calculations to discover small organic compounds able to selectively permeate cardiolipin-containing membranes. By employing transferable coarse-grained models we efficiently navigate the all-atom design space corresponding to small organic molecules with molecular weight less than ≈500 Da. After direct simulation of only 0.42% of our coarse-grained search space we identify molecules with considerably increased levels of cardiolipin selectivity compared to a widely used cardiolipin probe 10-N-nonyl acridine orange. Our accumulated simulation data enables us to derive interpretable design rules linking coarse-grained structure to cardiolipin selectivity. The findings are corroborated by fluorescence anisotropy measurements of two compounds conforming to our defined design rules. Our findings highlight the potential of coarse-grained representations and multiscale modelling for materials discovery and design.

We present a data-driven approach combining deep learning-enabled active learning with coarse-grained simulations and alchemical free energy calculations to discover small molecules to selectively permeate cardiolipin membranes.     

Variational Formulation of a General Equilibrium Model with Incomplete Financial Markets and Numeraire Assets: Existence

We present a general equilibrium model with incomplete financial markets and numeraire assets. We assume that there are 2 periods of time, say today and tomorrow. In period 0, households exchange goods and assets and then consumption takes place; in period 1, one of S possible states of nature occurs. In each of them, assets pay their returns, which are measured in units of a given physical good, i.e., the numeraire commodity; households exchange goods; finally, consumption takes place. We define a consumption, portfolio holding, commodity and asset price vector as an equilibrium vector associated with a given economy, if at those prices and economies households maximize, and market clears. While the existence proof by Geneakoplos and Polemarchakis (Essays in honor of K.J. Arrow, vol 3, Cambridge University Press, Cambridge, pp 65–95, 1986) uses a fixed point argument, we provide an independent existence result in terms of variational inequalities. That approach allows us to get the desired existence result under some different and more general or realistic assumptions than those usually made in the literature.     

Quantitative determination of magnetic fields from iron particles of oblong form encapsulated by carbon nanotubes using electron holography

Using electron holography (interference electron microscopy) we have made measurements of the magnetic flux and magnetic field distribution around a carbon nanotube filled with iron. At the surface of the carbon nanotube, an iron particle with a radius of 30 nm and a length of 200 nm created a magnetic flux of 10⁻¹⁵ Wb (Weber) and a magnetic field of 0.3–0.4 T (Tesla). The theory developed in this work is constrained to the case of cylindrical symmetry of the investigated ferromagnetic particles, but, in general, such studies can be made for ferromagnetic particles of any shape.     

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