Two Approaches in Computer Simulation of the MFM-images

Two approaches to the interpretation of the data of magnetic force microscopy are considered. The first approach involves the reconstruction of the magnetization distribution in the researched samples on the base of an assumption about the magnetic state and the subsequent numerical magnetic force microscopy experiment. The second is related to an experimental data processing

Graphene Oxide Promotes Site-Selective Allylic Alkylation of Thiophenes with Alcohols

The graphene oxide (GO) assisted allylic alkylation of thiophenes with alcohols is presented. Mild reaction conditions and a low GO loading enabled the isolation of a range of densely functionalized thienyl and bithienyl compounds in moderate to high yields (up to 90%). The cooperative action of the Bronsted acidity, epoxide moieties, and pi-surface of the 2D-promoter is highlighted as crucial in the reaction course of the present Friedel-Crafts-type protocol

Polaritonic Chemistry: Hindering and Easing Ground State Polyenic Isomerization via Breakdown of σ–π Separation

The ground state conformational isomerization in polyenes is a symmetry allowed process. Its low energy barrier is governed by electron density transfer from the formal single bond that is rotated to the nearby formal double bonds. Along the reaction pathway, the transition state is therefore destabilized. The rules of polaritonic chemistry, i.e., chemistry in a nanocavity with reflecting windows, are barely beginning to be laid out. The standing electric field of the nanocavity couples strongly with the molecular wave function and modifies the potential energy curve in unexpected ways. A quantum electrodynamics approach, applied to the torsional degree of freedom of the central bond of butadiene, shows that formation of the polariton mixes the σ–π frameworks thereby stabilizing/destabilizing the planar, reactant-like conformations. The values of the fundamental mode of the cavity field used in the absence of the cavity do not trigger this mechanism

Modeling Living Cells Response to Surface Tension and Chemical Patterns

Mechanobiology is an important epigenetic factor. It influences cell functioning and bears on gene induction, protein synthesis, cell growth, and differentiation. In the presence of patterned chemical cues, living cells can take shapes that are far from that of a drop of fluid. These shapes are characterized by inward curvatures that are pinned at the points of location of the cues. The mechanochemical interactions that orchestrate cell behavior is simulated and controlled by modeling the cells as made by parcels of fluid. Cells become drops that are then endowed with the presence of additional forces, generated on the fly, that effectively make them active. With the proper choice of the forces, the phenomena that emerge from the dynamics match quantitatively the experiments. A combination of hydrophilic and lipophilic forces acting between the beads of fluid allows the active drop to respond to patterned cues and form squares, pentagons, hexagons, and flowers, just as living cells do

Local Ice Melting by an Antifreeze Protein

Antifreeze proteins, AFP, impede freezing of bodily fluids and damaging of cellular tissues by low temperatures. Adsorption-inhibition mechanisms have been developed to explain their functioning. Using in silico Molecular Dynamics, we show that type I AFP can also induce melting of the local ice surface. Simulations of antifreeze-positive and antifreeze-negative mutants show a clear correlation between melting induction and antifreeze activity. The presence of local melting adds a function to type I AFPs that is unique to these proteins. It may also explain some apparently conflicting experimental results where binding to ice appears both quasipermanent and reversible

Local Ice Melting by an Antifreeze Protein

Antifreeze proteins, AFP, impede freezing of bodily fluids and damaging of cellular tissues by low temperatures. Adsorption-inhibition mechanisms have been developed to explain their functioning. Using in silico Molecular Dynamics, we show that type I AFP can also induce melting of the local ice surface. Simulations of antifreeze-positive and antifreeze-negative mutants show a clear correlation between melting induction and antifreeze activity. The presence of local melting adds a function to type I AFPs that is unique to these proteins. It may also explain some apparently conflicting experimental results where binding to ice appears both quasipermanent and reversible

Local Ice Melting by an Antifreeze Protein

Antifreeze proteins, AFP, impede freezing of bodily fluids and damaging of cellular tissues by low temperatures. Adsorption-inhibition mechanisms have been developed to explain their functioning. Using in silico Molecular Dynamics, we show that type I AFP can also induce melting of the local ice surface. Simulations of antifreeze-positive and antifreeze-negative mutants show a clear correlation between melting induction and antifreeze activity. The presence of local melting adds a function to type I AFPs that is unique to these proteins. It may also explain some apparently conflicting experimental results where binding to ice appears both quasipermanent and reversible

Modeling Living Cells Response to Surface Tension and Chemical Patterns

Mechanobiology is an important epigenetic factor. It influences cell functioning and bears on gene induction, protein synthesis, cell growth, and differentiation. In the presence of patterned chemical cues, living cells can take shapes that are far from that of a drop of fluid. These shapes are characterized by inward curvatures that are pinned at the points of location of the cues. The mechanochemical interactions that orchestrate cell behavior is simulated and controlled by modeling the cells as made by parcels of fluid. Cells become drops that are then endowed with the presence of additional forces, generated on the fly, that effectively make them active. With the proper choice of the forces, the phenomena that emerge from the dynamics match quantitatively the experiments. A combination of hydrophilic and lipophilic forces acting between the beads of fluid allows the active drop to respond to patterned cues and form squares, pentagons, hexagons, and flowers, just as living cells do

Modeling Living Cells Response to Surface Tension and Chemical Patterns

Mechanobiology is an important epigenetic factor. It influences cell functioning and bears on gene induction, protein synthesis, cell growth, and differentiation. In the presence of patterned chemical cues, living cells can take shapes that are far from that of a drop of fluid. These shapes are characterized by inward curvatures that are pinned at the points of location of the cues. The mechanochemical interactions that orchestrate cell behavior is simulated and controlled by modeling the cells as made by parcels of fluid. Cells become drops that are then endowed with the presence of additional forces, generated on the fly, that effectively make them active. With the proper choice of the forces, the phenomena that emerge from the dynamics match quantitatively the experiments. A combination of hydrophilic and lipophilic forces acting between the beads of fluid allows the active drop to respond to patterned cues and form squares, pentagons, hexagons, and flowers, just as living cells do

Thermodynamics of Binding Between Proteins and Carbon Nanoparticles: The Case of C₆₀@Lysozyme

The analysis of the interaction between C₆₀ and lysozyme provides general rules to identify the forces that govern the thermodynamics of binding between proteins and carbon nanoparticles. The main driving force of the binding are van der Waals interactions. Polar solvation and entropy, contributions that are often neglected, are strongly detrimental to the binding. These energetically relevant terms must be taken into account when protein/CNP hybrids are designed