26 research outputs found
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
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
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 C<sub>60</sub>@Lysozyme
The
analysis of the interaction between C<sub>60</sub> 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