scholarly journals Quantitative Estimation of Long-Range Interactions at the Nanoscale

2018 ◽  
Author(s):  
Vishesh Sood ◽  
Sunandan Dhar ◽  
Dhirendra S. Katti
Keyword(s):  
Surface Tension ◽  
Long Range ◽  
Protein Interactions ◽  
Quantitative Estimation ◽  
Surface Characteristics ◽  
Acid Base ◽  
Biologically Relevant ◽  
Nanoparticle Agglomeration ◽  
Biological Responses ◽  
Long Range Interactions

AbstractNano-bio interfaces attune nanoparticle-mediated biological responses. The nano-bio interface, like all interfacial interactions, is governed by non-covalent long-range interactions (LRIs). These LRIs include electrostatic, electrodynamic and acid-base interactions. There is a lack of understanding about the contribution of LRIs at the nano-bio interface for want of suitable methods for the estimation of dispersive, acidic, and basic components of the surface tension of nanoparticles. To address this, we developed an experimental and theoretical framework for the estimation of surface tension components of nanoparticles and biomacromolecules by partitioning them in a biphasic system. The work presented here is the first instance in the literature for estimating the surface tension components of nanoparticles and biomacromolecules suspended in aqueous suspensions. We also observed that LRIs have a deterministic role in biologically relevant phenomena such as salt-induced nanoparticle agglomeration and protein-nanoparticle interaction. Collectively, the results presented in this work provide a rapid and inexpensive framework for predicting the energetics of nanoparticle-nanoparticle and nanoparticle-protein interactions by estimating average ensemble surface characteristics like surface tension and surface charge density.

Effect of long-range interactions on the surface tension

2006 ◽  
Vol 80 (3) ◽  
pp. 445-448 ◽  
Author(s):  
E. A. Korochkova ◽  
G. Sh. Boltachev ◽  
V. G. Baidakov
Keyword(s):  
Surface Tension ◽  
Long Range ◽  
Long Range Interactions

Water-mediated long-range interactions between the internal vibrations of remote proteins

2015 ◽  
Vol 17 (10) ◽  
pp. 6728-6733 ◽  
Author(s):  
Anna Kuffel ◽  
Jan Zielkiewicz
Keyword(s):  
Long Range ◽  
Protein Interactions ◽  
Interfacial Water ◽  
Protein Protein Interactions ◽  
Partial Synchronization ◽  
Long Range Interactions ◽  
Internal Vibrations

We demonstrated that interfacial water can influence and mediate long-range protein–protein interactions leading to a partial synchronization of internal movements of proteins.

scholarly journals Structural Changes in the Acceptor Site of Photosystem II upon Ca2+/Sr2+ Exchange in the Mn4CaO5 Cluster Site and the Possible Long-Range Interactions

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 371
Author(s):  
Koua
Keyword(s):  
Crystal Structure ◽  
Photosystem Ii ◽  
Long Range ◽  
Electron Acceptor ◽  
Structural Changes ◽  
Acceptor Site ◽  
Oxygen Evolving Complex ◽  
Long Range Interactions ◽  
Structural Perturbations ◽  
Oxygen Evolving

The Mn4CaO5 cluster site in the oxygen-evolving complex (OEC) of photosystem II (PSII) undergoes structural perturbations, such as those induced by Ca2+/Sr2+ exchanges or Ca/Mn removal. These changes have been known to induce long-range positive shifts (between +30 and +150 mV) in the redox potential of the primary quinone electron acceptor plastoquinone A (QA), which is located 40 Å from the OEC. To further investigate these effects, we reanalyzed the crystal structure of Sr-PSII resolved at 2.1 Å and compared it with the native Ca-PSII resolved at 1.9 Å. Here, we focus on the acceptor site and report the possible long-range interactions between the donor, Mn4Ca(Sr)O5 cluster, and acceptor sites.

scholarly journals Detecting long-range interactions between migrating cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Metzner ◽  
F. Hörsch ◽  
C. Mark ◽  
T. Czerwinski ◽  
A. Winterl ◽  
...  
Keyword(s):  
Nk Cells ◽  
Tumor Cells ◽  
Long Range ◽  
Cooperative Behavior ◽  
Simulated Data ◽  
Movement Direction ◽  
Repulsive Interaction ◽  
Collagen Gels ◽  
Long Range Interactions ◽  
A Cell

AbstractChemotaxis enables cells to systematically approach distant targets that emit a diffusible guiding substance. However, the visual observation of an encounter between a cell and a target does not necessarily indicate the presence of a chemotactic approach mechanism, as even a blindly migrating cell can come across a target by chance. To distinguish between the chemotactic approach and blind migration, we present an objective method that is based on the analysis of time-lapse recorded cell migration trajectories: For each movement step of a cell relative to the position of a potential target, we compute a p value that quantifies the likelihood of the movement direction under the null-hypothesis of blind migration. The resulting distribution of p values, pooled over all recorded cell trajectories, is then compared to an ensemble of reference distributions in which the positions of targets are randomized. First, we validate our method with simulated data, demonstrating that it reliably detects the presence or absence of remote cell-cell interactions. In a second step, we apply the method to data from three-dimensional collagen gels, interspersed with highly migratory natural killer (NK) cells that were derived from two different human donors. We find for one of the donors an attractive interaction between the NK cells, pointing to a cooperative behavior of these immune cells. When adding nearly stationary K562 tumor cells to the system, we find a repulsive interaction between K562 and NK cells for one of the donors. By contrast, we find attractive interactions between NK cells and an IL-15-secreting variant of K562 tumor cells. We therefore speculate that NK cells find wild-type tumor cells only by chance, but are programmed to leave a target quickly after a close encounter. We provide a freely available Python implementation of our p value method that can serve as a general tool for detecting long-range interactions in collective systems of self-driven agents.

scholarly journals A novel class of translationally invariant spin chains with long-range interactions

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
B. Basu-Mallick ◽  
F. Finkel ◽  
A. González-López
Keyword(s):  
Long Range ◽  
Degrees Of Freedom ◽  
Spin Chains ◽  
Open Chain ◽  
New Class ◽  
Spin Interactions ◽  
Long Range Interactions ◽  
Spin Reversal ◽  
Twisted Yangian ◽  
Internal Degrees Of Freedom

Abstract We introduce a new class of open, translationally invariant spin chains with long-range interactions depending on both spin permutation and (polarized) spin reversal operators, which includes the Haldane-Shastry chain as a particular degenerate case. The new class is characterized by the fact that the Hamiltonian is invariant under “twisted” translations, combining an ordinary translation with a spin flip at one end of the chain. It includes a remarkable model with elliptic spin-spin interactions, smoothly interpolating between the XXX Heisenberg model with anti-periodic boundary conditions and a new open chain with sites uniformly spaced on a half-circle and interactions inversely proportional to the square of the distance between the spins. We are able to compute in closed form the partition function of the latter chain, thereby obtaining a complete description of its spectrum in terms of a pair of independent su(1|1) and su(m/2) motifs when the number m of internal degrees of freedom is even. This implies that the even m model is invariant under the direct sum of the Yangians Y (gl(1|1)) and Y (gl(0|m/2)). We also analyze several statistical properties of the new chain’s spectrum. In particular, we show that it is highly degenerate, which strongly suggests the existence of an underlying (twisted) Yangian symmetry also for odd m.

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