scholarly journals Hydrophobic Nanoparticles Drives Size-Dependent Remodelling in Asymmetric Bilayers

Author(s):  
Sang Noh ◽  
Rebecca Notman

The interactions between heterogeneous components in a biomimetic bilayer controls its physical properties such as its rigidity, local and bulk curvature and propensity towards phenomena such as membrane fission and fusion. In particular, membrane proteins (MPs) and nanoparticles (NPs) have been subjects of intense interest due to their similar scale to the bilayer width and because of their ability to affect local membrane structure. However, how such NPs interact in the presence of heterogeneous aggregates in the bilayer has been the subject of much debate, especially its effect on raft-like structures. To better understand the effects of hydrophobic integration of nanoscale components on such raft-like structures, we have simulated a series of generic hydrophobic NPs interacting with a phase-separating two-component surfactant bilayer. We find that the hydrophobic NP tends to aggregate at the phase interface, acting as a line tension relaxant i.e. a lineactant on the phase separated interface, which results in differing demixing behavior. In particular, we demonstrate that depending on the size of the NP, the effect of the line tension can drive the a cap/bud formation around the NP, ultimately resulting in the formation of a NP-micelle structure.<br><br>

2020 ◽  
Author(s):  
Sang Noh ◽  
Rebecca Notman

The interactions between heterogeneous components in a biomimetic bilayer controls its physical properties such as its rigidity, local and bulk curvature and propensity towards phenomena such as membrane fission and fusion. In particular, membrane proteins (MPs) and nanoparticles (NPs) have been subjects of intense interest due to their similar scale to the bilayer width and because of their ability to affect local membrane structure. However, how such NPs interact in the presence of heterogeneous aggregates in the bilayer has been the subject of much debate, especially its effect on raft-like structures. To better understand the effects of hydrophobic integration of nanoscale components on such raft-like structures, we have simulated a series of generic hydrophobic NPs interacting with a phase-separating two-component surfactant bilayer. We find that the hydrophobic NP tends to aggregate at the phase interface, acting as a line tension relaxant i.e. a lineactant on the phase separated interface, which results in differing demixing behavior. In particular, we demonstrate that depending on the size of the NP, the effect of the line tension can drive the a cap/bud formation around the NP, ultimately resulting in the formation of a NP-micelle structure.<br><br>


2020 ◽  
Author(s):  
Sang Noh ◽  
Rebecca Notman

The interactions between heterogeneous components in a biomimetic bilayer can control its physical properties such as its rigidity, local and bulk curvature and propensity towards phenomena such as membrane fission and fusion. In particular, nanoparticles (NPs) have been subjects of intense interest due to their similar scale to the bilayer width and its ability to affect local membrane structure. Generally, it is understood that hydrophobic components are energetically favoured to adsorb within the hydrophobic interior of a biomimetic bilayer. However, how such NPs interact in the presence of heterogeneous aggregates in the bilayer has been the subject of much debate. To better understand the effects of the integration of nanoscale components on heterogeneous mixed bilayer, we have simulated a series of generic hydrophobic NPs interacting with a phase-separating two-component surfactant bilayer. We find that the hydrophobic NP tends to aggregate at the phase interface, acting as a line tension relaxant i.e. a lineactant on the phase separated interface, which results in a variety of demixing behavior. We demonstrate that depending on the size of the NP, the localized softening of surfactants and the formation of a mixing gradient of surfactants can drive the a cap/bud formation around the NP, as well as the formation of a NP-micelle structure<br>


2020 ◽  
Author(s):  
Sang Noh ◽  
Rebecca Notman

The interactions between heterogeneous components in a biomimetic bilayer can control its physical properties such as its rigidity, local and bulk curvature and propensity towards phenomena such as membrane fission and fusion. In particular, nanoparticles (NPs) have been subjects of intense interest due to their similar scale to the bilayer width and its ability to affect local membrane structure. Generally, it is understood that hydrophobic components are energetically favoured to adsorb within the hydrophobic interior of a biomimetic bilayer. However, how such NPs interact in the presence of heterogeneous aggregates in the bilayer has been the subject of much debate. To better understand the effects of the integration of nanoscale components on heterogeneous mixed bilayer, we have simulated a series of generic hydrophobic NPs interacting with a phase-separating two-component surfactant bilayer. We find that the hydrophobic NP tends to aggregate at the phase interface, acting as a line tension relaxant i.e. a lineactant on the phase separated interface, which results in a variety of demixing behavior. We demonstrate that depending on the size of the NP, the localized softening of surfactants and the formation of a mixing gradient of surfactants can drive the a cap/bud formation around the NP, as well as the formation of a NP-micelle structure<br>


Author(s):  
A. S. Sharipov ◽  
◽  
B. I. Loukhovitski ◽  

The size-dependence of different physical properties of atomic clusters (by the example of binding energy, collision diameter, and static isotropic polarizability) is discussed.


Of the commoner mineral acids the chemical changes of Nitric Acid, from their evident complexity, have formed the subject of numerous memoirs, while those of sulphuric acid, from their assumed simplicity, have been to some degree neglected; on the other hand, the physical properties of the latter have been studied with considerable elaboration, while those of the former have been passed over, doubtless on account of the corrosive nature of the acid and the difficulty of preparing and preserving it in a reasonable degree of purity. Further, with certain exceptions, the alterations in physical properties induced by the products of reduction, be they nitrogen peroxide or nitrous acid, either singly or conjointly, have attracted but little attention, though it is a common matter of observation that the current intensity of a Grove’s or other cell containing nitric acid remains constant, even though the fuming acid, originally colourless or red, has become of a deep green tint. It is more than probable that of the factors of Ohm’s law, both the E. M. F. and internal resistance are continually varying. At the earliest stages of the enquiry it was found that the passage of a few bubbles of nitric oxide gas into a considerable volume of nitric acid produced an alteration of one percent, in the resistance, and the same result could be effected to a less degree by exposure to sunlight, and to a still less degree by exposure to artificial illumination. Therefore, we determined to investigate the alterations of conductivity produced by changes of concentration and temperature in samples of acid purified with necessary precautions, more especially as former workers upon the subject have either used samples of acid confessedly impure, or have been silent as to any method of purification, or have adopted no special care in dealing with a substance so susceptible of polarisation.


1851 ◽  
Vol 141 ◽  
pp. 357-398 ◽  

About twelve months ago I had the honour of presenting to the Royal Society an account of a series of researches into the molecular constitution of the volatile organic bases: at present I beg to submit to the consideration of the Society the history of a new group of alkaloids, which, although intimately connected with the former by their origin, differ from them altogether by their properties, and especially in not being volatile . The members of this new group of alkaloids are so numerous, their deportment is so singular, and their derivatives ramify in so many directions, that I have not as yet been able to complete the study of these substances in all their bearings; nor is it my intention to go fully into the chemistry of the subject in the present com­munication, my object being merely to establish the existence of these bodies, and to give a general outline of their connection with the volatile bases, and of their most prominent chemical and physical properties, reserving a detailed description of their salts and derivatives to a future memoir.


2018 ◽  
Vol 51 (7) ◽  
pp. 2411-2417 ◽  
Author(s):  
Shanqiu Liu ◽  
Anupam Pandey ◽  
Joost Duvigneau ◽  
Julius Vancso ◽  
Jacco H. Snoeijer

Open Physics ◽  
2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Jorge G. Cardoso

AbstractIt is assumed that the two-component spinor formalisms for curved spacetimes that are endowed with torsionful affine connexions can supply a local description of dark energy in terms of classical massive spin-one uncharged fields. The relevant wave functions are related to torsional affine potentials which bear invariance under the action of the generalized Weyl gauge group. Such potentials are thus taken to carry an observable character and emerge from contracted spin affinities whose patterns are chosen in a suitable way. New covariant calculational techniques are then developed towards deriving explicitly the wave equations that supposedly control the propagation in spacetime of the dark energy background. What immediately comes out of this derivation is a presumably natural display of interactions between the fields and both spin torsion and curvatures. The physical properties that may arise directly fromthe solutions to thewave equations are not brought out.


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