Angular momentum of fission fragments

We continue the discussion on the respective roles of individual and collective motion in the angular momentum distribution in fission fragments. As in our prior publications on the subject, the role of individual nucleon motion in fragments in the postscission configuration is underlined, and the central part in the discussion concerns phenomena observed in the spontaneous fission of even-even nuclei. A formalism is prepared to study the spin distribution of fragments in induced fission from high-spin states.     

Well‐posedness,positivity, and time asymptotics properties for a reaction–diffusion model of plankton communities,involving a rational nonlinearity with singularity

In this work, we consider a reaction–diffusion system, modeling the interaction between nutrients, phytoplankton, and zooplankton. Using a semigroup approach in , we prove global existence, uniqueness, and positivity of the solutions. The nonlinearity is handled by providing estimates in , allowing to deal with most of the functional responses that describe predator/prey interactions (Holling I, II, III, Ivlev) in ecology. The paper finally exhibits some time asymptotic properties of the solutions.     

Mechanosensitive Membrane Probes

This article assembles pertinent insights behind the concept of planarizable push–pull probes. As a response to the planarization of their polarized ground state, a red shift of their excitation maximum is expected to report on either the disorder, the tension, or the potential of biomembranes. The combination of chromophore planarization and polarization contributes to various, usually more complex processes in nature. Examples include the color change of crabs or lobsters during cooking or the chemistry of vision, particularly color vision. The summary of lessons from nature is followed by an overview of mechanosensitive organic materials. Although often twisted and sometimes also polarized, their change of color under pressure usually originates from changes in their crystal packing. Intriguing exceptions include the planarization of several elegantly twisted phenylethynyl oligomers and polymers. Also mechanosensitive probes in plastics usually respond to stretching by disassembly. True ground‐state planarization in response to molecular recognition is best exemplified with the binding of thoughtfully twisted cationic polythiophenes to single‐ and double‐stranded oligonucleotides. Molecular rotors, en vogue as viscosity sensors in cells, operate by deplanarization of the first excited state. Pertinent recent examples are described, focusing on λ‐ratiometry and intracellular targeting. Complementary to planarization of the ground state with twisted push–pull probes, molecular rotors report on environmental changes with quenching or shifts in emission rather than absorption. The labeling of mechanosensitive channels is discussed as a bioengineering approach to bypass the challenge to create molecular mechanosensitivity and use biological systems instead to sense membrane tension. With planarizable push–pull probes, this challenge is met not with twistome screening, but with “fluorescent flippers,” a new concept to insert large and bright monomers into oligomeric probes to really feel the environment and also shine when twisted out of conjugation.     

Mechanochromic Luminescence of Copper Iodide Clusters

Luminescent mechanochromic materials are particularly appealing for the development of stimuli‐responsive materials. Establishing the mechanism responsible for the mechanochromism is always an issue owing to the difficulty in characterizing the ground phase. Herein, the study of real crystalline polymorphs of a mechanochromic and thermochromic luminescent copper iodide cluster permits us to clearly establish the mechanism involved. The local disruption of the crystal packing induces changes in the cluster geometry and in particular the modification of the cuprophilic interactions, which consequently modify the emissive states. This study constitutes a step further toward the understanding of the mechanism involved in the mechanochromic luminescent properties of multimetallic coordination complexes.     

Definable types in the theory of closed ordered differential fields

We study definable types in the theory of closed ordered differential fields (CODF). We show a condition for a type to be definable, then we prove that definable types are dense in the Stone space of CODF.