Article
Chemistry, Physical
Giuseppe Lanza, Maria Assunta Chiacchio
Summary: This passage discusses the structures of the first hydration shell of alkanes, emphasizing their ability to adapt to the solute's shape, avoid wasting hydrogen bonds, and maximize solvent-solute van der Waals interactions. Computational results used in the study show that the van der Waals interactions in the hydration shell are substantial, and the high exoenergetic values for certain alkanes can explain the high melting points of related hydrates.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Medicinal
Prabir Khatua, Madhulika Gupta, Sanjoy Bandyopadhyay
Summary: This study investigates the conformational properties of amyloid beta (Aβ) peptides and the role of solvent (water) in guiding the dynamical environment at their interfaces. Molecular dynamics simulations reveal that the dynamics of water molecules around different segments of Aβ peptides are nonuniform and correlated with the hydrogen bond relaxation time scales. The water molecules around hp1 and hp2 form relatively rigid hydration layers, which are crucial in understanding the early stages of Aβ peptide aggregation.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2022)
Article
Chemistry, Physical
HaoLun Wu, Mohammad Reza Ghaani, Prithwish K. Nandi, Niall J. English
Summary: Water plays a fundamental role in biological activity as a regulating agent. This study reveals that external electric fields have clear non-thermal effects on the dipolar response of proteins and their hydration layers, primarily due to the alignment of protein dipoles with the electric field.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Biochemistry & Molecular Biology
Nadezda A. Penkova, Mars G. Sharapov, Nikita Penkov
Summary: The hydration shells of DNA were studied in solution by terahertz time-domain spectroscopy, revealing differences from undisturbed water in terms of the presence of strongly bound water molecules, a higher number of free molecules, and an increased number of hydrogen bonds. Salts in the solution had varying effects on hydration, with MgCl2 having minimal alteration and KCl significantly attenuating hydration effects.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Chemistry, Physical
Joanna Grabowska, Anna Kuffel, Jan Zielkiewicz
Summary: Using computer simulations, it was found that ordered aggregates of water molecules are formed in the solvation layer of hydrophobic molecules, becoming more pronounced with decreasing temperature. This phenomenon around the hydrophobic solutes supports the concept of icebergs proposed by Frank and Evans.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Chemistry, Physical
Kang Hu, Ryo Shirakashi
Summary: In this study, we investigated the relationship between water rotational dynamics and the exerted internal electric field using molecular dynamics simulation. We found that the rotation of water molecules synchronizes with the reorientation of the overall electric field. Furthermore, the rotational dynamics are influenced by the reorientation of the local electric field within the hydration layer.
Article
Chemistry, Physical
Qingcheng Hu, Haiwen Zhao, Shunli Ouyang, Yuying Liang, Huimin Yang, Xuefeng Zhu
Summary: The Raman spectra of (D2O + H2O) - NaCl solutions at different ratios were analyzed. Water structures in the solutions were discussed based on solute-correlated (SC) OD/OH stretch bands. The results showed that isotopic substitution had an effect on the relative intensity of high-wavenumber modes and led to structural transitions. The hydration shell mainly consisted of single donor (SD) and single hydrogen-bond water (SHW) configurations. The increase of isotopic substitution ratio strengthened the interaction between D2O and Cl- in the hydration shell.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Chemistry, Physical
Kang Hu, Hiroaki Matsuura, Ryo Shirakashi
Summary: Water dynamics is crucial for biochemical processes. This study combines MD simulations and BDS to investigate the rotational dynamics of water around lysozyme. The results show that water rotation is severely restricted within 3A from the lysozyme surface.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Chemistry, Multidisciplinary
Kevin Leung
Summary: This study demonstrates that in confined electrolytes at hydrothermal conditions, the dielectric permittivity profile perpendicular to the slit increases with ionic concentration at strictly zero frequency, contrary to the behavior observed in the megahertz-to-gigahertz frequency range. This finding has important implications for geochemical, energy storage, and electrochemical applications, as it reveals the complex behavior of confined electrolytes.
Article
Physics, Fluids & Plasmas
Theo Hennequin, Manoel Manghi, John Palmeri
Summary: The recent study on the dielectric constant of water confined in nanometric slit pores sheds light on the interplay between different physical mechanisms for ion partitioning in nanopores. The role of the Born contribution in inducing ionic liquid-vapor phase separation is explored, showing that the abrupt change in the dielectric contribution of the potential of mean force with Debye-Huckel screening parameters favors this transition. By establishing phase diagrams and monitoring osmotic pressure, the study reveals the competition between exclusion effects and electrostatic attraction in charged nanopores, providing insights for experiments and simulations on ionic transport through nanopores.
Article
Chemistry, Multidisciplinary
Hugh P. Ryan, Zachary S. Fishman, Jacob T. Pawlik, Angela Grommet, Malgorzata Musial, Felix Rizzuto, James C. Booth, Christian J. Long, Kathleen Schwarz, Nathan D. Orloff, Jonathan R. Nitschke, Angela C. Stelson
Summary: The environment around a host-guest complex is determined by intermolecular interactions and plays a crucial role in their solubility and reaction rates. However, these interactions are difficult to detect with standard analytical techniques. In this study, we used microwave microfluidic measurements and principal component analysis to quantify the hydration and ion pairing of a coordination cage. The results showed that introducing guest molecules into the solution displaced the bound counterions and the solvent solubility of the guest had the greatest impact on the solvent and ion-pairing dynamics surrounding the host.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Biochemistry & Molecular Biology
Nikita Penkov
Summary: This research focuses on the dynamic hydration characteristics of carbohydrates in aqueous solutions using terahertz time-domain spectroscopy analysis. It reveals that all analyzed carbohydrates increase the binding degree of water, with monosaccharides showing higher numbers of hydrogen bonds and free water molecules but polysaccharides exhibiting less apparent hydration depending on the type of glycosidic bonds.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Biophysics
Korey M. Reid, Abhishek K. Singh, Chowdhury R. Bikash, Jessica Wei, Yftah Tal-Gan, Nguyen Q. Vinh, David M. Leitner
Summary: Proteins and water exhibit dynamic coupling at different time scales. The coupling dynamics between intrinsically disordered proteins (IDPs) and water are found to be more complex compared to structured proteins, potentially due to the interactions between water molecules and charged groups.
BIOPHYSICAL JOURNAL
(2022)
Article
Chemistry, Physical
Sayantan Mondal, Biman Bagchi
Summary: The study focuses on understanding the anomalous dielectric properties of nanoconfined water in different systems, finding surface influence on dielectric response and characteristics of water. Parameters such as correlation lengths are calculated to reveal the frequencies and features influencing the dielectric response of water, which are particularly prominent for water.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Physics, Fluids & Plasmas
I. V. Krivtsun, A. I. Momot, D. V. Antoniv, Binhao Qin
Summary: The characteristics of atmospheric pressure Ar-plasma, including the spatial distributions of number densities, fluxes, and temperatures of electrons and heavy plasma particles, as well as the spatial distribution of electric potential around an individual spherical particle, were studied numerically. The governing equations for plasma without thermal and ionization equilibrium were formulated, and the boundary conditions near the particle were set. The nonlinear problem was solved considering the temperature dependencies of transport and kinetic coefficients. The heat flux introduced by the plasma into the particle was calculated and compared with the results of the simple heat conduction model. The range of particle radius (10^(-5) - 10^(-4) m) and unperturbed plasma temperature (6-18 kK) were considered.
PHYSICS OF PLASMAS
(2023)
Article
Biophysics
Sebastian J. Mueller, Franziska Weigl, Carina Bezold, Christian Baecher, Krystyna Albrecht, Stephan Gekle
Summary: In this study, a numerical model is proposed to simulate the deformation of biological cells in arbitrary three-dimensional flows, calibrated using experimental data and validated through comparison to previous experiments on different types of cells and particles.
BIOMECHANICS AND MODELING IN MECHANOBIOLOGY
(2021)
Article
Mechanics
Katharina Graessel, Christian Baecher, Stephan Gekle
Summary: This study investigates the influence of anisotropy on the Rayleigh-Plateau instability mechanism under various surface tension conditions. It reveals the significant impact of anisotropy on the dominant wavelength of instability, as well as the formation of satellite droplets under anisotropic tension. The research combines analytical linear stability analysis with numerical simulations to explore the effects of different tension scenarios on instability behavior.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Christian Baecher, Katharina Graessel, Stephan Gekle
Summary: This study examines the Rayleigh-Plateau instability of cylindrical vesicles and cell membranes under tension, considering the combined influence of anisotropic tension and membrane elasticity. The research shows that the combination of bending elasticity and tension anisotropy leads to three qualitatively different regimes for the Rayleigh-Plateau scenario, while shear elasticity and area dilatation only exhibit the classical and suppressed regimes.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Polymer Science
Soren Schumacher, Sanwardhini Pantawane, Stephan Gekle, Seema Agarwal
Summary: The synthesis and polymerization behavior of four different monofunctional vinyl cyclopropane (VCP) derivatives were investigated. The study found that different VCPs have varying abilities to form hydrogen bonds in their side chains, leading to preorganization and potentially faster polymerization. Although VCPs capable of hydrogen bonding did not show significant differences, a general effect of hydrogen bonds on polymerization behavior was observed.
Article
Hematology
Francois Yaya, Johannes Roemer, Achim Guckenberger, Thomas John, Stephan Gekle, Thomas Podgorski, Christian Wagner
Summary: The objective of the study was to investigate the flow field of plasma around red blood cells in capillary flow, with experimental results showing different flow fields around red blood cells of different shapes and vortex structures changing with the distance between cells.
Article
Polymer Science
Sanwardhini Pantawane, Stephan Gekle
Summary: In this study, atomistic and coarse-grained molecular dynamics simulations were used to investigate the conformation of a single poly(3-hexylthiopene) chain at different temperatures. It was found that bundle and toroid structures were predominantly present, with bundles becoming more abundant at lower temperatures. A comparison of atomistic and Martini-based coarse-grained models showed excellent agreement. Furthermore, the temperature dependence of P3HT was linked to that of simple Lennard-Jones model polymers in a vacuum. The addition of solvent (THF) resulted in a prominent swelling of the molecular size at around 220 K, which correlated well with experimental observations of increased frequency of bundle structures.
Article
Chemistry, Multidisciplinary
Chen Liang, Jun Young Cheong, Gabriel Sitaru, Sabine Rosenfeldt, Anna S. Schenk, Stephan Gekle, II-Doo Kim, Andreas Greiner
Summary: The study shows that, for citrate and polyvinylpyrrolidone stabilized gold nanoparticles, the reactivity increases with increasing particle diameter in the size range of 10-58 nm when the total surface area is kept constant. Furthermore, internal structural parameters such as defect tendency also play a significant role in catalytic activity.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Computer Science, Interdisciplinary Applications
Gabriel Sitaru, Stephan Gekle
Summary: Multistep catalytic reactions using chemically incompatible catalysts were studied by immobilizing the catalysts on fibrous membranes. The efficiency of the reactions was investigated using three different methods. The results showed that although the efficiency decreased with increased flow speed, the total production still increased. Additionally, the spatial proximity of the catalysts had a positive effect on the reaction efficiency.
COMPUTERS & FLUIDS
(2022)
Article
Polymer Science
Soren Schumacher, Sanwardhini Pantawane, Stephan Gekle, Seema Agarwal
Summary: This study presents the synthesis of four different monofunctional vinyl cyclopropane amides and investigates their photopolymerization behavior. It is found that all the amides can form hydrogen bonds, with one being the amide linkage and the other being the side chain. The number of additional hydrogen bonds is regulated by different side chains. The study demonstrates that hydrogen bonds can preorganize the monomers and lead to fast polymerization.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2022)
Article
Biology
Richard Gerum, Elham Mirzahossein, Mar Eroles, Jennifer Elsterer, Astrid Mainka, Andreas Bauer, Selina Sonntag, Alexander Winterl, Johannes Bartl, Lena Fischer, Shada Abuhattum, Ruchi Goswami, Salvatore Girardo, Jochen Guck, Stefan Schruefer, Nadine Stroehlein, Mojtaba Nosratlo, Harald Herrmann, Dorothea Schultheis, Felix Rico, Sebastian Johannes Mueller, Stephan Gekle, Ben Fabry
Summary: This study presents a high-throughput, simple, and low-cost microfluidic method to quantitatively measure the elastic and viscous moduli of individual cells. By measuring cell deformation and rotation frequency, the frequency-dependent viscoelastic properties of cells can be determined, revealing the influence of cell cycle and physical interactions between different cell structures.
Article
Physics, Applied
Sebastian J. Mueller, Ben Fabry, Stephan Gekle
Summary: Bioprinting of living cells can lead to shape deformations, affecting cell survival and functionality. Extensional stresses occurring when cells leave the nozzle have been ignored. Lattice Boltzmann simulations and a finite-element based cell model were used to study cell deformation inside the nozzle and at its exit. Two simple methods were developed to predict maximum cell stress and approximate cell strains based on printing parameters.
PHYSICAL REVIEW APPLIED
(2023)
Article
Physics, Fluids & Plasmas
Steffen M. Recktenwald, Katharina Graessel, Yazdan Rashidi, Jann Niklas Steuer, Thomas John, Stephan Gekle, Christian Wagner
Summary: Constricted blood vessels in the circulatory system can cause complications by affecting the organization of red blood cells. In this study, the dynamics of a cell-free layer (CFL) in a constricted microchannel under steady and time-dependent flow conditions were examined. A image-processing routine was developed to analyze the CFL evolution under various flow conditions. The results showed that the concentration of red blood cells and the amplitude of the pressure signal had dominant effects on the CFL dynamics.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Physics, Fluids & Plasmas
Moritz Lehmann, Mathias J. Krause, Giorgio Amati, Marcello Sega, Jens Harting, Stephan Gekle
Summary: This study evaluates the feasibility of using different precision optimization algorithms in lattice Boltzmann method and finds that the accuracy difference between FP32 and 16-bit precision can be neglected in most cases.
Article
Mathematics, Interdisciplinary Applications
Moritz Lehmann, Stephan Gekle
Summary: The plane-cube intersection problem and its iterative solutions have been extensively studied in computational fluid dynamics simulation. This study proposes an improved analytic solution for all intersection cases and compares it with the previous solution from Scardovelli and Zaleski. The authors also evaluate the performance and accuracy of different solutions on different hardware platforms, and discuss the application of PLIC-curvature calculation in free surface fluid simulations.
Article
Biophysics
Steffen M. Recktenwald, Katharina Graessel, Felix M. Maurer, Thomas John, Stephan Gekle, Christian Wagner
Summary: The dynamics and shape transitions of single red blood cells (RBCs) under confined and unsteady flow conditions were investigated using microfluidic experiments and numerical simulations. It was found that the transition time from the symmetric croissant to the off-centered, nonsymmetric slipper shape was faster than the opposite shape transition. Simulations showed that these dynamics depend on the orientation of the RBC membrane in the channel during the time-dependent flow. The tank-treading movement of slipper-shaped RBCs combined with the narrow channel led to oscillations of the cell's center of mass.
BIOPHYSICAL JOURNAL
(2022)
