scholarly journals Hyaluronan orders water molecules in its nanoscale extended hydration shells

2021 ◽  
Vol 7 (10) ◽  
pp. eabf2558
Author(s):  
J. Dedic ◽  
H. I. Okur ◽  
S. Roke
Keyword(s):  
Second Harmonic ◽  
Hydration Shell ◽  
Water Molecules ◽  
Temperature Dependent ◽  
Flexible Chain ◽  
Optical Modeling ◽  
Hydration Shells ◽  
Second Harmonic Scattering ◽  
Nuclear Quantum Effects ◽  
Extracellular Environment

Hyaluronan (HA) is an anionic, highly hydrated bio-polyelectrolyte found in the extracellular environment, like the synovial fluid between joints. We explore the extended hydration shell structure of HA in water using femtosecond elastic second-harmonic scattering (fs-ESHS). HA enhances orientational water-water correlations. Angle-resolved fs-ESHS measurements and nonlinear optical modeling show that HA behaves like a flexible chain surrounded by extended shells of orientationally correlated water. We describe several ways to determine the concentration-dependent size and shape of a polyelectrolyte in water, using the amount of water oriented by the polyelectrolyte charges as a contrast agent. The spatial extent of the hydration shell is determined via temperature-dependent measurements and can reach up to 475 nm, corresponding to a length of 1600 water molecules. A strong isotope effect, stemming from nuclear quantum effects, is observed when light water (H2O) is replaced by heavy water (D2O), amounting to a factor of 4.3 in the scattered SH intensity.

scholarly journals Polyelectrolytes induce water-water correlations that result in dramatic viscosity changes and nuclear quantum effects

2019 ◽  
Vol 5 (12) ◽  
pp. eaay1443 ◽  
Author(s):  
J. Dedic ◽  
H. I. Okur ◽  
S. Roke
Keyword(s):  
Long Range ◽  
Electrostatic Interactions ◽  
Second Harmonic ◽  
Mean Field ◽  
Quantum Effects ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Hydration Shells ◽  
Polyelectrolyte Solutions ◽  
Nuclear Quantum Effects

Ions interact with water via short-ranged ion-dipole interactions. Recently, an additional unexpected long-ranged interaction was found: The total electric field of ions influences water-water correlations over tens of hydration shells, leading to the Jones Ray effect, a 0.3% surface tension depression. Here, we report such long-range interactions contributing substantially to both molecular and macroscopic properties. Femtosecond elastic second harmonic scattering (fs-ESHS) shows that long-range electrostatic interactions are remarkably strong in aqueous polyelectrolyte solutions, leading to an increase in water-water correlations. This increase plays a role in the reduced viscosity, which changes more than two orders of magnitude with polyelectrolyte concentration. Using D2O instead of H2O shifts both the fs-ESHS and the viscosity curve by a factor of ~10 and reduces the maximum viscosity value by 20 to 300%, depending on the polyelectrolyte. These phenomena cannot be explained using a mean-field approximation of the solvent and point to nuclear quantum effects.

Origin of ion selectivity at the air/water interface

2015 ◽  
Vol 17 (6) ◽  
pp. 4311-4318 ◽  
Author(s):  
Lu Sun ◽  
Xin Li ◽  
Yaoquan Tu ◽  
Hans Ågren
Keyword(s):  
Hydrogen Bonds ◽  
Weak Interactions ◽  
Ion Selectivity ◽  
Hydration Shell ◽  
Water Molecules ◽  
Water Interface ◽  
Hydration Shells ◽  
Air Water Interface ◽  
Water Hydrogen ◽  
First Hydration Shell

A snapshot of a water droplet consisting of Cs+ and I− ions with their hydration structures displayed. I− is hydrated anisotropically and the water–water hydrogen bonds in the first hydration shell are hindered. The anions have quite weak interactions with non-hydrogen-bonded water molecules in the first hydration shell, making it easier for them to leave the site. In contrast, cations obtain more stable hydration shells with an increase in their size.

Infrared study of the state of water in the hydration shell of DNA

1970 ◽  
Vol 48 (10) ◽  
pp. 1536-1542 ◽  
Author(s):  
Michael Falk ◽  
A. G. Poole ◽  
C. G. Goymour
Keyword(s):  
Liquid Water ◽  
Low Temperatures ◽  
Hydration Shell ◽  
The State ◽  
Water Molecules ◽  
Surrounding Water ◽  
Infrared Study ◽  
Hydration Shells ◽  
State Of Water ◽  
Bond Strengths

The state of water in the hydration shell of DNA was studied by infrared spectroscopy. The stretching bands of isotopically dilute HDO adsorbed on DNA have nearly the same band profiles as those of HDO in liquid water. This indicates a distribution of hydrogen-bond strengths similar to that in liquid water. At low temperatures, the spectra show that an inner layer of about 10 water molecules per nucleotide is incapable of crystallization, even when the surrounding water crystallizes into ice I. The biopolymer hydration shells are not "ice-like" in the sense of crystalline ordering into an ice-like structure.

Hydration Shell Structures in an MgCl2 Solution from X-Ray and MD Studies

1982 ◽  
Vol 37 (9) ◽  
pp. 1049-1060 ◽  
Author(s):  
G. Pálinkás ◽  
T. Radnai
Keyword(s):  
Nearest Neighbor ◽  
Hydration Shell ◽  
Lone Pair ◽  
Model Fit ◽  
Dynamics Simulation ◽  
Scattering Data ◽  
Water Molecules ◽  
X Ray ◽  
Hydration Shells ◽  
Density Maps

Abstract The results of a molecular dynamics simulation of a 1.1 molal aqueous MgCl2 solution are com-pared with newly performed x-ray measurements. The structural properties of the solution are evaluated from the scattering data by a model fit to the experimental structure function. The comparison on the basis of fit parameters and partial structure functions shows an overall good agreement between experiment and simulation.Detailed information on the structure of the hydration shells is deduced from the simulation and shown in form of density maps and angular distributions. It is demonstrated that the octahedral arrangement of the water molecules in the first hydration shell of Mg++ is strongly pronounced while it is only indicated in the case of Cl-. A preferential arrangement in tetrahedral directions has been found for the nearest neighbor water molecules around a central water molecule with an asymmetry in respect to lone pair and hydrogen atom directions. In addition, the probability of finding water molecules at a given number of symmetry sites at the same time has been calculated.

scholarly journals Modeling the Effect of Hydration on the Electronic and Vibrational Properties of AZT

2020 ◽  
Vol 11 (2) ◽  
pp. 9253-9265
Keyword(s):  
Active Sites ◽  
Density Functional ◽  
Hydration Shell ◽  
Water Molecules ◽  
Functional Theory ◽  
Hydration Shells ◽  
Immunodeficiency Virus ◽  
Ir Frequencies ◽  
Homo Lumo

The 3'-azido-3'-deoxythymidine, which is termed AZT, was introduced as anti-human immunodeficiency virus HIV. AZT is supposed to interact with water molecules forming two hydration shells. In the first shell, five water molecules were surrounding five active sites. Each water molecule then further interacted with two water molecules forming the second hydration shell. The computational note is dedicated on the basis of density functional theory (DFT). So that, DFT:B3LYP/6-31G(d,p) was used to follow up on the changes in AZT as a result of hydration. The DFT was used to calculate total dipole moment (TDM), HOMO/LUMO bandgap energies, molecular electrostatic potential (MESP), and IR frequencies.

scholarly journals Hydration Shells of DNA from the Point of View of Terahertz Time-Domain Spectroscopy

2021 ◽  
Vol 22 (20) ◽  
pp. 11089
Author(s):  
Nadezda A. Penkova ◽  
Mars G. Sharapov ◽  
Nikita V. Penkov
Keyword(s):  
Time Domain ◽  
Hydration Shell ◽  
Bound Water ◽  
Free Water ◽  
Point Of View ◽  
Water Molecules ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Effective Medium Model ◽  
Hydration Shells

Hydration plays a fundamental role in DNA structure and functioning. However, the hydration shell has been studied only up to the scale of 10–20 water molecules per nucleotide. In the current work, hydration shells of DNA were studied in a solution by terahertz time-domain spectroscopy. The THz spectra of three DNA solutions (in water, 40mm MgCl2 and 150 mM KCl) were transformed using an effective medium model to obtain dielectric permittivities of the water phase of solutions. Then, the parameters of two relaxation bands related to bound and free water molecules, as well as to intermolecular oscillations, were calculated. The hydration shells of DNA differ from undisturbed water by the presence of strongly bound water molecules, a higher number of free molecules and an increased number of hydrogen bonds. The presence of 40 mM MgCl2 in the solution almost does not alter the hydration shell parameters. At the same time, 150 mM KCl significantly attenuates all the found effects of hydration. Different effects of salts on hydration cannot be explained by the difference in ionic strength of solutions, they should be attributed to the specific action of Mg2+ and K+ ions. The obtained results significantly expand the existing knowledge about DNA hydration and demonstrate a high potential for using the THz time-domain spectroscopy method.

Use of Second Harmonic and Thermal Effects of Laser Voltage Probing for Better Fault Isolation

2016 ◽  
Author(s):  
Ramya Yeluri ◽  
Ravishankar Thirugnanasambandam ◽  
Cameron Wagner ◽  
Jonathan Urtecho ◽  
Jan M. Neirynck
Keyword(s):  
Duty Cycle ◽  
Thermal Effects ◽  
Second Harmonic ◽  
Fault Isolation ◽  
Advanced Technology ◽  
Temperature Dependent ◽  
First Case ◽  
Improve Accuracy ◽  
Degradation Monitoring ◽  
Technology Nodes

Abstract Laser voltage probing (LVP) has been extensively used for fault isolation over the last decade; however fault isolation in practice primarily relies on good-to-bad comparisons. In the case of complex logic failures at advanced technology nodes, understanding the components of the measured data can improve accuracy and speed of fault isolation. This work demonstrates the use of second harmonic and thermal effects of LVP to improve fault isolation with specific examples. In the first case, second harmonic frequency is used to identify duty cycle degradation. Monitoring the relative amplitude of the second harmonic helps identify minute deviations in the duty cycle with a scan over a region, as opposed to collecting multiple high resolution waveforms at each node. This can be used to identify timing degradation such as signal slope variation as well. In the second example, identifying abnormal data at the failing device as temperature dependent effect helps refine the fault isolation further.

scholarly journals Solid-Phase “Self-Hydrolysis” of [Zn(NH3)4MoO4@2H2O] Involving Enclathrated Water—An Easy Route to a Layered Basic Ammonium Zinc Molybdate Coordination Polymer

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4022
Author(s):  
Kende Attila Béres ◽  
István E. Sajó ◽  
György Lendvay ◽  
László Trif ◽  
Vladimir M. Petruševski ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
Solid Phase ◽  
Water Molecules ◽  
Temperature Dependent ◽  
Dynamic Interactions ◽  
Ammonia Release ◽  
Successive Substitution ◽  
Red Dye ◽  
Hydrolysis Of ◽  
Zinc Molybdate

An aerial humidity-induced solid-phase hydrolytic transformation of the [Zn(NH3)4]MoO4@2H2O (compound 1@2H2O) with the formation of [(NH4)xH(1−x)Zn(OH)(MoO4)]n (x = 0.92–0.94) coordination polymer (formally NH4Zn(OH)MoO4, compound 2) is described. Based on the isostructural relationship, the powder XRD indicates that the crystal lattice of compound 1@2H2O contains a hydrogen-bonded network of tetraamminezinc (2+) and molybdate (2−) ions, and there are cavities (O4N4(μ-H12) cube) occupied by the two water molecules, which stabilize the crystal structure. Several observations indicate that the water molecules have no fixed positions in the lattice voids; instead, the cavity provides a neighborhood similar to those in clathrates. The @ symbol in the notation is intended to emphasize that the H2O in this compound is enclathrated rather than being water of crystallization. Yet, signs of temperature-dependent dynamic interactions with the wall of the cages can be detected, and 1@2H2O easily releases its water content even on standing and yields compound 2. Surprisingly, hydrolysis products of 1 were observed even in the absence of aerial humidity, which suggests a unique solid-phase quasi-intramolecular hydrolysis. A mechanism involving successive substitution of the ammonia ligands by water molecules and ammonia release is proposed. An ESR study of the Cu-doped compound 2 (2#dotCu) showed that this complex consists of two different Cu2+(Zn2+) environments in the polymeric structure. Thermal decomposition of compounds 1 and 2 results in ZnMoO4 with similar specific surface area and morphology. The ZnMoO4 samples prepared from compounds 1 and 2 and compound 2 in itself are active photocatalysts in the degradation of Congo Red dye. IR, Raman, and UV studies on compounds 1@2H2O and 2 are discussed in detail.

scholarly journals Structure of aqueous sodium acetate solutions by X-Ray scattering and density functional theory

2020 ◽  
Vol 92 (10) ◽  
pp. 1627-1641
Author(s):  
Guangguo Wang ◽  
Yongquan Zhou ◽  
He Lin ◽  
Zhuanfang Jing ◽  
Hongyan Liu ◽  
...  
Keyword(s):  
Sodium Acetate ◽  
Density Functional ◽  
Hydration Shell ◽  
Ion Pair ◽  
Water Molecules ◽  
Sodium Acetate Solution ◽  
Acetate Solution ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

AbstractThe structure of aq. sodium acetate solution (CH3COONa, NaOAc) was studied by X-ray scattering and density function theory (DFT). For the first hydrated layer of Na+, coordination number (CN) between Na+ and O(W, I) decreases from 5.02 ± 0.85 at 0.976 mol/L to 3.62 ± 1.21 at 4.453 mol/L. The hydration of carbonyl oxygen (OC) and hydroxyl oxygen (OOC) of CH3COO− were investigated separately and the OC shows a stronger hydration bonds comparing with OOC. With concentrations increasing, the hydration shell structures of CH3COO− are not affected by the presence of large number of ions, each CH3COO− group binds about 6.23 ± 2.01 to 7.35 ± 1.73 water molecules, which indicates a relatively strong interaction between CH3COO− and water molecules. The larger uncertainty of the CN of Na+ and OC(OOC) reflects the relative looseness of Na-OC and Na-OOC ion pairs in aq. NaOAc solutions, even at the highest concentration (4.453 mol/L), suggesting the lack of contact ion pair (CIP) formation. In aq. NaOAc solutions, the so called “structure breaking” property of Na+ and CH3COO− become effective only for the second hydration sphere of bulk water. The DFT calculations of CH3COONa (H2O)n=5–7 clusters suggest that the solvent-shared ion pair (SIP) structures appear at n = 6 and become dominant at n = 7, which is well consistent with the result from X-ray scattering.

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