Unraveling Adaptation in Eukaryotic Pathways: Lessons from Protocells

Eukaryotic adaptation pathways operate within wide-ranging environmental conditions without stimulus saturation. Despite numerous differences in the adaptation mechanisms employed by bacteria and eukaryotes, all require energy consumption. Here, we present two minimal models showing that expenditure of energy by the cell is not essential for adaptation. Both models share important features with large eukaryotic cells: they employ small diffusible molecules and involve receptor subunits resembling highly conserved G-protein cascades. Analyzing the drawbacks of these models helps us understand the benefits of energy consumption, in terms of adjustability of response and adaptation times as well as separation of cell-external sensing and cell-internal signaling. Our work thus sheds new light on the evolution of adaptation mechanisms in complex systems.Comment: accepted for publication in PLoS Computational Biology; 19 pages, 8 figure

Quantum reservoirs with ion chains

Ion chains are promising platforms for studying and simulating quantum reservoirs. One interesting feature is that their vibrational modes can mediate entanglement between two objects which are coupled through the vibrational modes of the chain. In this work we analyse entanglement between the transverse vibrations of two heavy impurity defects embedded in an ion chain, which is generated by the coupling with the chain vibrations. We verify general scaling properties of the defects dynamics and demonstrate that entanglement between the defects can be a stationary feature of these dynamics. We then analyse entanglement in chains composed of tens of ions and propose a measurement scheme which allows one to verify the existence of the predicted entangled state.Comment: 14 pages, 12 figure

Dynamics of entanglement creation between two spins coupled to a chain

We study the dynamics of entanglement between two spins which is created by the coupling to a common thermal reservoir. The reservoir is a spin-$\frac{1}{2}$ Ising transverse field chain thermally excited, the two defect spins couple to two spins of the chain which can be at a macroscopic distance. In the weak-coupling and low-temperature limit the spin chain is mapped onto a bath of linearly interacting oscillators using the Holstein-Primakoff transformation. We analyse the time evolution of the density matrix of the two defect spins for transient times and deduce the entanglement which is generated by the common reservoir. We discuss several scenarios for different initial states of the two spins and for varying distances.Comment: 16 pages, 5 figure

Evaluation of effect of the primary particle size on compactibility of spray-dried lactoses

Spray-dried lactose is one of the most used filler-binders in direct compaction of tablets. Spray-dried lactose is produced by spray-drying a suspension of α-lactose monohydrate crystals in a saturated aqueous solution of lactoses. The resulting product is composed of spherical particles, containing 80-85% crystals of α-lactose monohydrate (primary particles) and 15-20% amorphous lactose The compactibility of two commercial spray-dried lactoses, Pharmatose® DCL 11 (DCL11), prepared from α-lactose monohydrate with a median primary particle size of 34 µm and a new product, Pharmatose® DCL 14 (DCL14), prepared from 20 µm primary particles, were investigated

La adulación entre modelos clásicos y desengaño

La adulación, según observa Starobinski, es una noción que permite examinar unos aspectos de la vida social del punto de vista psicológico, pero, al mismo tiempo, de considerar según la perspectiva social ciertos aspectos de la psicología. En este trabajo se analiza la fenomenología de la adulación / lisonja en varios contextos de la obra, en verso y en prosa, de Quevedo. Retomando el hilo de la tradición clásica, del neoestoicismo y de la crítica cristiana en contra del mundano deseo de bienes terrenales, Quevedo explora el abanico semántico de la noción de lisonja y su fenomenología bajo el perfil social y psicológico. According to Starobinski, the concept of adulation allows to treat from a psychological point of view some aspects of social life and to face as well some aspects of psychological life from a social point of view. This article examines several passages of Quevedo’s work, poetry as well as prose, in which the author explores thoroughly, in both respects, the semantic configuration of «lisonja» deriving his approach from the classical tradition and from the Christian thought as well as from his personal experience

A new subfamily of fungal subtilases: structural and functional analysis of a Pleurotus ostreatus member

Pleurotus ostreatus produces several extracellular proteases which are believed to be involved in the regulation of the ligninolytic activities of this fungus. Recently, purification and characterization of the most abundant P. ostreatus extracellular protease (PoSl) have been reported. The sequence of the posl gene and of the corresponding cDNA has been determined, allowing the identification of its pre- and pro-sequences. A mature protein sequence has been verified by mass spectrometry mapping, the N-glycosylation sites have been identified and the glycosidic moieties characterized. Mature PoSl shows a cleaved peptide bond in the C-terminal region, which remains associated with the catalytic domain in a non-covalent complex. Reported results indicate that this enzyme is involved in the activation of other P. ostreatus secreted proteases, thus suggesting its leading role in cascade activation mechanisms. Analyses of the PoSl sequence by homology search resulted in the identification of a DNA sequence encoding a new protease, homologous to PoSl, in the Phanerochaete chrysosporium genome. A new subgroup of subtilisin-like proteases, belonging to the pyrolysin family, has been defined, which includes proteases from ascomycete and basidiomycete fungi

Entangling two defects via a surrounding crystal

We theoretically show how two impurity defects in a crystalline structure can be entangled through coupling with the crystal. We demonstrate this with a harmonic chain of trapped ions in which two ions of a different species are embedded. Entanglement is found for sufficiently cold chains and for a certain class of initial, separable states of the defects. It results from the interplay between localized modes which involve the defects and the interposed ions, it is independent of the chain size, and decays slowly with the distance between the impurities. These dynamics can be observed in systems exhibiting spatial order, viable realizations are optical lattices, optomechanical systems, or cavity arrays in circuit QED.Comment: 5 pages, 5 figure

Entangled light pulses from single cold atoms

The coherent interaction between a laser-driven single trapped atom and an optical high-finesse resonator allows to produce entangled multi-photon light pulses on demand. The mechanism is based on the mechanical effect of light. The degree of entanglement can be controlled through the parameters of the laser excitation. Experimental realization of the scheme is within reach of current technology. A variation of the technique allows for controlled generation of entangled subsequent pulses, with the atomic motion serving as intermediate memory of the quantum state.Comment: 4 pages, 3 figures, revised version (new scheme for generation of subsequent pairs of entangled pulses included). Accepted for publication in Phys. Rev. Let

Erythrocyte's aging in microgravity highlights how environmental stimuli shape metabolism and morphology

The determination of the function of cells in zero-gravity conditions is a subject of interest in many different research fields. Due to their metabolic unicity, the characterization of the behaviour of erythrocytes maintained in prolonged microgravity conditions is of particular importance. Here, we used a 3D-clinostat to assess the microgravity-induced modifications of the structure and function of these cells, by investigating how they translate these peculiar mechanical stimuli into modifications, with potential clinical interest, of the biochemical pathways and the aging processes. We compared the erythrocyte's structural parameters and selected metabolic indicators that are characteristic of the aging in microgravity and standard static incubation conditions. The results suggest that, at first, human erythrocytes react to external stimuli by adapting their metabolic patterns and the rate of consumption of the cell resources. On longer timeframes, the cells translate even small differences in the environment mechanical solicitations into structural and morphologic features, leading to distinctive morphological patterns of agin

A real options based model to select a balanced R&D portfolio

The R&D process in the pharmaceutical industry has a long and dynamic life then it is an ideal field of application for ROA. Actually, ROA implementation, as widely demonstrated in literature, is narrowed to very limited cases because its perceived complexity. This research wants to suggest a simplified method, respect the ones available in literature, that could foster the use of ROA: we built up an integer linear programming model, based on a model available in literature, useful for selecting a balanced R&D portfolio from a set of candidate drugs. The model has been tested through a case study