scholarly journals Propensity, free energy contributions and conformation of primary n-alcohols at a water surface

2021 ◽  
Author(s):  
Victor Ekholm ◽  
Carl Caleman ◽  
Jochen S. Hub ◽  
Malin Wohlert
Keyword(s):  
Free Energy ◽  
Water Surface ◽  
Primary Alcohol ◽  
Surface Adsorption ◽  
Bulk Water ◽  
Hydrophobic Tail

The transition of primary alcohol molecules from bulk water to the surface is driven by entropy, increasing linearly with length of the hydrophobic tail. The enthalpy of surface adsorption is nearly invariant with increasing length of the molecule.

scholarly journals Peptide-Surface Adsorption Free Energy Comparing Solution Conditions Ranging from Low to Medium Salt Concentrations

ChemPhysChem ◽  
2012 ◽  
Vol 13 (17) ◽  
pp. 3782-3785 ◽  
Author(s):  
Yang Wei ◽  
Aby A. Thyparambil ◽  
Robert A. Latour
Keyword(s):  
Free Energy ◽  
Surface Adsorption ◽  
Adsorption Free Energy

scholarly journals All-atom molecular dynamics study of hepatitis B virus containing pregenome RNA in solution

2021 ◽  
Author(s):  
Kazushi Fujimoto ◽  
Youhei Yamaguchi ◽  
Ryo Urano ◽  
Wataru Shinoda ◽  
Tetsuya Ishikawa ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Ion Selectivity ◽  
Bulk Water ◽  
Field Analysis ◽  
Nucleotide Analogue ◽  
Capsid Shell ◽  
B Virus

Immature hepatitis B virus (HBV) captures nucleotides in its capsid for reverse transcription. The nucleotides and nucleotide analogue drugs, which are triphosphorylated and negatively charged in the cell, approach the capsid via diffusion and are absorbed into it. In this study, we performed a long-time molecular dynamics (MD) calculation of the entire HBV capsid containing pregenome RNA to investigate the interactions between the capsid and negatively charged substances. Electric field analysis demonstrated that negatively charged substances can approach the HBV capsid by thermal motion, avoiding spikes. The substances then migrate all over the floor of the HBV capsid. Finally, they find pores through which they can pass through the HBV capsid shell. Free energy profiles were calculated along these pores for small ions to understand their permeability through the pores. Anions (Cl-) showed higher free energy barriers than cations (Na+ and K+) through all pores, and the permeation rate of Cl- was eight times slower than that of K+ or Na+. Furthermore, the ions were more stable in the capsid than in the bulk water. Thus, the HBV capsid exerts ion selectivity for uptake and provides an environment for ions, such as nucleotides and nucleotide analogue drugs, to be stabilized within the capsid.

Atomic structure of Ni-Nb-Y amorphous alloys and water-surface adsorption characteristics

2019 ◽  
Vol 169 ◽  
pp. 109095 ◽  
Author(s):  
Sean Grixti ◽  
Shwetank Yadav ◽  
Steven Thorpe ◽  
Chandra Veer Singh
Keyword(s):  
Atomic Structure ◽  
Amorphous Alloys ◽  
Water Surface ◽  
Surface Adsorption ◽  
Adsorption Characteristics

Adsorption of a Diverse Set of Organic Vapors on the Bulk Water Surface

2002 ◽  
Vol 252 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Christine M. Roth ◽  
Kai-Uwe Goss ◽  
René P. Schwarzenbach
Keyword(s):  
Water Surface ◽  
Bulk Water ◽  
Organic Vapors

ROLE OF SOLVENT IN SLURRY PHASE REACTIONS

2008 ◽  
Vol 15 (06) ◽  
pp. 805-808
Author(s):  
YAN ZHOU ◽  
KAI HU ◽  
JUNFENG SHEN ◽  
ZHENPING JI ◽  
GONGZHEN CHENG
Keyword(s):  
Water Surface ◽  
High Efficiency ◽  
Bound Water ◽  
Bulk Water ◽  
Chemical Activity ◽  
Phase Reaction ◽  
Slurry Phase ◽  
Surface Hydroxylation ◽  
Role Of Solvent

There exists an optimal amount of solvent (generally water) that can be added to the slurry phase reaction between solid reactants; the reactivity and efficiency of such reactions are different from those without solvent or those with large amount of solvent. Obviously, the solvent plays a crucial role in the process of the reaction, and it is the key to the understanding of unique reactivity and high efficiency of such slurry phase reactions. The water molecule absorbed on the surface of solid reactants, which is called bound water, has uniquely different properties compared with bulk water. Surface hydroxylation resulting from bound water greatly influences the chemical activity of the surface, which could be playing a role as catalyst or as the initialization point for further reactions, so that the reactants can react easily and fast under a simple reaction condition.

Effects of Inorganic Cations on Na+ Adsorption to the Gill and Body Surface of Rainbow Trout, Oncorhynchus mykiss, in Dilute Solutions

1991 ◽  
Vol 48 (10) ◽  
pp. 1829-1837 ◽  
Author(s):  
R. D. Handy ◽  
F. B. Eddy
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Body Surface ◽  
Water Adsorption ◽  
Surface Adsorption ◽  
Bulk Water ◽  
Apical Surface ◽  
Inorganic Cations ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Adsorption Phenomena

Using the shortest practical exposure time (15 s) to 0.2 mmol∙L−1 NaCl solutions containing 22Na, over 80% of the Na+ taken up by rainbow trout, Oncorhynchus mykiss, was located on the gill or body surface (adsorption). Influx to the blood (absorption) was less than 20% of the total taken up, even though Na+ entry into the blood was detected in less than 30 s. Sodium adsorption to the fish surface was strongly reduced by micromolar concentrations of Ca2+ or by acid in the range pH 7–5. At higher NaCl concentrations (2 mmol∙L−1 in the medium, Ca2+ effects on adsorption were greatly attenuated. Aluminum had a negligible effect on adsorption at pH 4. It is concluded that adsorption has an important role in presenting Na+ to the apical surface of gill ion transporting cells, since conditions which inhibit the branchial influx of Na+ also reduce Na+ adsorption. The results suggest that adsorption is controlled by ion exchange events at gill surface ligands, and by the effects of other cations on the mobility of Na+ in the bulk water. Adsorption phenomena are likely to influence ionic regulation during normal fluctuations in environmental conditions.

scholarly journals Removal of Pyrethrin from Aqueous Effluents by Adsorptive Micellar Flocculation

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Pardon K. Kuipa ◽  
Olga Kuipa
Keyword(s):  
Free Energy ◽  
Sodium Dodecyl Sulphate ◽  
Adsorption Process ◽  
Sodium Dodecyl ◽  
Surface Adsorption ◽  
Adsorption Model ◽  
Equilibrium Isotherms ◽  
Aluminium Sulphate ◽  
Aqueous Effluents ◽  
The Mean

The equilibrium adsorption of pyrethrin onto aggregates formed by the flocculation of micelles of the surfactant sodium dodecyl sulphate (SDS) with aluminium sulphate is reported. The experimental results were analysed using different adsorption isotherms (Langmuir, Freundlich, Redlich-Peterson, Sips, Radke-Prausnitz, Temkin, linear equilibrium, and the Dubin-Radushkevich isotherms). The Freundlich and linear equilibrium isotherms best describe the adsorption of pyrethrin onto SDS micellar flocs, with the Freundlich adsorption constant,KF, and the mass distribution coefficient,KD, of 64.266 ((mg/g)(L/mg)1/n) and 119.65 L/g, respectively. Applicability of the Freundlich adsorption model suggests that heterogeneous surface adsorption affects the adsorption. The mean free energy value estimated using the Dubinin-Radushkevich isotherm was 0.136 kJ/mol indicating that physisorption may be predominant in the adsorption process.

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