scholarly journals Evaluation of Radiation Resistance of Polystyrene Using Molecular Dynamics Simulation

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 346
Author(s):  
Yeong-Heum Yeon ◽  
Ha-Eun Shim ◽  
Jin-Hyung Park ◽  
Nam-Ho Lee ◽  
Jae-Yeon Park ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Average Molecular Weight ◽  
Absorbed Dose ◽  
Gel Permeation Chromatography ◽  
Dynamics Simulation ◽  
Molecular Weight Distributions ◽  
Radiation Enhancement ◽  
Γ Rays

The scission rates of polystyrene and fluorinated polystyrene irradiated in an irradiation facility with Co-60 γ-rays were determined using molecular dynamics simulation and gel permeation chromatography (GPC) molecular weight distributions. The prediction was based on the assumption that γ-ray energy is transferred to the initial velocity of the primary knock-on atom. We employed a molecular dynamics simulation procedure to compute the changes in bond length between the connections for selected values of the absorbed dose and compared the calculated values with measurements made on the irradiated samples. The samples were exposed to four different absorbed doses of 25, 50, 75, and 100 kGy. The scission process and scission ratio were simulated with LAMMPS with ReaxFF potential for each bond, and we compared the simulation results with the experimental data especially measuring average molecular weight to evaluate the effect of fluorination on radiation enhancement.

Effect of Molecular Weight on Lubricant Depletion in a Heat Assisted Magnetic Recording System

2017 ◽  
Author(s):  
Deng Pan ◽  
Wenping Song
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Magnetic Recording ◽  
Recording System ◽  
Dynamics Simulation ◽  
Disk System ◽  
Heat Assisted Magnetic Recording ◽  
Lubricant Depletion

A model for studying lubricant depletion in HAMR slider/disk system was developed based on molecular dynamics simulation. We found that the lubricant molecular weight has small effect on lubricant depletion.

Strahlenempfindlichkeit von Bakteriophagen-DNS /Radiation sensitivity of Bacteriophage DNA

1969 ◽  
Vol 24 (7) ◽  
pp. 885-893 ◽  
Author(s):  
Thérèse Coquerelle ◽  
Leuthold Bohne ◽  
Ulrich Hagen ◽  
Jürgen Merkwitz
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Linear Part ◽  
Sedimentation Coefficient ◽  
Radiation Sensitivity ◽  
Quadratic Term ◽  
Molecular Weight Distributions ◽  
Γ Rays ◽  
Higher Doses

DNA isolated from Coli bacteriophage T1 was irradiated in 0.165 ᴍ NaCl with γ-rays. The molecular weight was determined by measurement of the sedimentation coefficient and viscosity. An analysis of the boundary permits the determination of the sedimentation distribution. The distribution of sedimentation coefficients obtained at various DNA concentrations were extrapolated to zero concentration and were transformed into molecular weight distributions. These were used to calculate the weight average molecular weight Mw and the number average molecular weight Mn.The molecular weight of T1-DNA was found to be 32· 106. After irradiation at a concentration of 200 μg/ml, double breaks as well as intermolecular crosslinks could be determined. The number of double breaks showed a rise with dose that can best be described as composed of a linear and a quadratic term. At low doses the crosslinks increase linearly, the rate being approximately half of that for the linear part of the double breaks. After higher doses, where most of the molecules are degraded, apparently no additional crosslinks are produced. No crosslinks were seen in DNA degraded by DNase. The influence of the DNA concentration on the degradation and the formation of crosslinks is discussed.

scholarly journals A double-edged sword: supramolecular complexes of triazavirine display multicenter binding effects which influence aggregate formation

2018 ◽  
Author(s):  
Yana A Zabrodskaya ◽  
Alexey V Shvetsov ◽  
Vladimir B Tsvetkov ◽  
Vladimir V Egorov
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Docking ◽  
Molecular Dynamics Simulation ◽  
Antiviral Activity ◽  
Small Molecule ◽  
Broad Spectrum ◽  
Dynamics Simulation ◽  
Supramolecular Complexes ◽  
Aggregate Formation

Triazavirine (TZV), a small molecule with a broad spectrum of antiviral activity, shows a tendency to induce the aggregation of melittin (MLT), a cationic membrane-disrupting peptide from the poison of the European bee. In MLT:TZV mixtures, high molecular weight precipitates form once a critical MLT:TZV ratio has been exceeded. Molecular dynamics simulation of MLT-TZV interactions, followed by molecular docking, led us to the hypothesis of multicenter binding of TZV supramolecular complexes to MLT.

scholarly journals Synthesis and Molecular Dynamics Simulation of Amphiphilic Low Molecular Weight Polymer Viscosity Reducer for Heavy Oil Cold Recovery

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6856
Author(s):  
Chao Ma ◽  
Xingyu Liu ◽  
Longlong Xie ◽  
Yan Chen ◽  
Wendong Ren ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Potential Energy ◽  
Network Structure ◽  
Heavy Oil ◽  
Dynamics Simulation ◽  
Viscosity Reduction ◽  
Low Molecular Weight ◽  
Viscosity Reducer

In order to reduce the viscosity of heavy oil, the performance of emulsifying viscosity reducers is limited. In this study, a new kind of amphiphilic low molecular weight viscosity reducer was prepared by emulsion copolymerization of acrylamide (AM), acrylic acid (AA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and Butene benzene (PB). The synthesis feasibility and viscosity reduction mechanism of viscosity reducer in heavy oil were explored using Materials Studio software from the perspective of molecular dynamics. The results of the molecular dynamics simulation revealed that the addition of viscosity reducer into heavy oil varied the potential energy, non-potential energy, density and hydrogen bond distribution of heavy oil. Benefiting from its structure, the benzene ring in PB was well embedded in the interlayer structure of asphaltene, contributing to weaken the network structure of the heavy oil. Moreover, the two strong polar groups (COO− and SO3−) of AA and AMPS, which constituted the branched chains of the viscosity reducer’s molecular structure, gradually disassembled the network structure from the ‘inward’ to the ‘outward’ of the heavy oil network structure, thereby driving heavy oil viscosity reduction (as clarified by molecular dynamics). Owing to its temperature resistance, this kind of new amphiphilic low molecular copolymer could be an effective viscosity reducer for heavy oil cold recovery at elevated temperatures.

scholarly journals Lysine Dendrigraft Nanocontainers. Influence of Topology on Their Size and Internal Structure

Pharmaceutics ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 129 ◽  
Author(s):  
Boris Okrugin ◽  
Maxim Ilyash ◽  
Denis Markelov ◽  
Igor Neelov
Keyword(s):  
Drug Delivery ◽  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Density Profile ◽  
Simulation Study ◽  
Biomedical Applications ◽  
Dynamics Simulation ◽  
Third Generation ◽  
Internal Structures

Poly-l-ysine dendrigrafts are promising systems for biomedical applications due to their biodegradability, biocompatibility, and similarity to dendrimers. There are many papers about the use of dendrigrafts as nanocontainers for drug delivery. At the same time, the number of studies about their physical properties is limited, and computer simulations of dendrigrafts are almost absent. This paper presents the results of a systematic molecular dynamics simulation study of third-generation lysine dendrigrafts with different topologies. The size and internal structures of the dendrigrafts were calculated. We discovered that the size of dendrigrafts of the same molecular weight depends on their topology. The shape of all studied dendrigrafts is close to spherical. Density profile of dendrigrafts depends on their topology.

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