Flow dynamics and theoretical modeling of monolayer ionic solutions confined within Ångstrom-scale channels.

Comprehending the flow dynamics of ionic solutions within nanoconfined spaces is imperative for diverse applications encompassing desalination, nanofiltration, energy storage, and electrochemical devices. When the confinement space is further reduced to 1 nm (Ångstrom scale), monolayer ionic solutions will emerge. In this regime, ions not only have the ability to influence water properties such as viscosity but also primarily modify the interactions and corresponding slip length (or friction coefficient) between the solution and wall.

Cytokinin-related genes regulate cucumber fruit pedicel length.

Pedicel length is a crucial agronomic trait of cucumbers. Fruit deformation can occur When the pedicel is too long or too short. Moreover, an appropriate pedicel length is advantageous for mechanized harvesting.

Single nucleotide polymorphisms in SEPALLATA 2 underlie fruit length variation in cucurbits.

Complete disruption of critical genes is generally accompanied by severe growth and developmental defects, which dramatically hinder its utilization in crop breeding. Identifying subtle changes, such as single-nucleotide polymorphisms (SNPs), in critical genes that specifically modulate a favorable trait is a prerequisite to fulfill breeding potential. Here, we found 2 SNPs in the E-class floral organ identity gene cucumber (Cucumis sativus) SEPALLATA2 (CsSEP2) that specifically regulate fruit length.

Interlink between Abnormal Water Imbibition in Hydrophilic and Rapid Flow in Hydrophobic Nanochannels.

Nanoscale extension and refinement of the Lucas-Washburn model is presented with a detailed analysis of recent experimental data and extensive molecular dynamics simulations to investigate rapid water flow and water imbibition within nanocapillaries. Through a comparative analysis of capillary rise in hydrophilic nanochannels, an unexpected reversal of the anticipated trend, with an abnormal peak, of imbibition length below the size of 3 nm was discovered in hydrophilic nanochannels, surprisingly sharing the same physical origin as the well-known peak observed in flow rate within hydrophobic nanochannels. The extended imbibition model is applicable across diverse spatiotemporal scales and validated against simulation results and existing experimental data for both hydrophilic and hydrophobic nanochannels.

Advances in Two-Dimensional Ion-Selective Membranes: Bridging Nanoscale Insights to Industrial-Scale Salinity Gradient Energy Harvesting.

Salinity gradient energy, often referred to as the Gibbs free energy difference between saltwater and freshwater, is recognized as "blue energy" due to its inherent cleanliness, renewability, and continuous availability. Reverse electrodialysis (RED), relying on ion-selective membranes, stands as one of the most prevalent and promising methods for harnessing salinity gradient energy to generate electricity. Nevertheless, conventional RED membranes face challenges such as insufficient ion selectivity and transport rates and the difficulty of achieving the minimum commercial energy density threshold of 5 W/m.

Transcriptomic and physiological analysis of atractylodes chinensis in response to drought stress reveals the putative genes related to sesquiterpenoid biosynthesis.

Background: Atractylodes chinensis (DC) Koidz., a dicotyledonous and hypogeal germination species, is an important medicinal plant because its rhizome is enriched in sesquiterpenes. The development and production of A.

Unexpected Behavior in Thermal Conductivity of Confined Monolayer Water.

Monolayer water can be formed under extreme confinement and will present distinctive thermodynamic properties compared with bulk water. In this work, we perform molecular dynamics simulations to study the thermal conductivity of monolayer water confined in graphene channels, finding an unexpected way of thermal conductivity of monolayer water dependent on its number density, which has a close correlation with the structure of water. The monolayer water is in an amorphous state, and its thermal conductivity increases linearly with the area density when the water density is low at first.

regulates fruit shape via mediating cell division direction and cell expansion in cucumber.

Fruit shape and size are important appearance and yield traits in cucumber, but the underlying genes and their regulatory mechanisms remain poorly understood. Here we identified a mutant with spherical fruits from an Ethyl Methane Sulfonate (EMS)-mutagenized library, named the mutant. Compared with the cylindrical fruit shape in 32X (wild type), the fruit shape in was round due to reduced fruit length and increased fruit diameter.

A hydrogen bond-modulated soft nanoscale water channel for ion transport through liquid-liquid interfaces.

Ion transport through interfaces is of ubiquitous importance in many fields such as electrochemistry, emulsion stabilization, phase transfer catalysis, liquid-liquid extraction and enhanced oil recovery. However, the knowledge of interfacial structures that significantly affect ion transport through liquid-liquid interfaces is still lacking due to the difficulty of observing nanoscale interfaces. We studied here the evolution of interfacial structures during ion transport through the decane-water interface under different ionic concentrations and external forces using molecular dynamics simulations.

Comparative transcriptome analysis reveals sesquiterpenoid biosynthesis among 1-, 2- and 3-year old Atractylodes chinensis.

Background: Atractylodes chinensis (DC.) Koidz is a well-known medicinal plant containing the major bioactive compound, atractylodin, a sesquiterpenoid. High-performance liquid chromatography (HPLC) analysis demonstrated that atractylodin was most abundant in 3-year old A.

Extending the Classical Continuum Theory to Describe Water Flow through Two-Dimensional Nanopores.

Water flow through two-dimensional nanopores has attracted significant attention owing to the promising water purification technology based on atomically thick membranes. However, the theoretical description of water flow in nanopores based on the classical continuum theory is very challenging owing to the pronounced entrance/exit effects. Here, we extend the classical Hagen-Poiseuille equation for describing the relationship between flow rate and pressure loss in laminar tube flow to two-dimensional nanopores.

Theoretical description of molecular permeation via surface diffusion through graphene nanopores.

We establish a theoretical model to describe the surface molecular permeation through two-dimensional graphene nanopores based on the surface diffusion equation and Fick's law. The model is established by considering molecular adsorption and desorption from the surface adsorption layer and the molecular diffusion and concentration gradient on the graphene surface. By comparing with the surface flux obtained from molecular dynamics simulations, it is shown that the model can predict well the overall permeation flux especially for strongly adsorbed molecules (i.

Wall friction should be decoupled from fluid viscosity for the prediction of nanoscale flow.

The accurate determination of fluid viscosity based on the microscopic information of molecules is very crucial for the prediction of nanoscale flow. Despite the challenge of this problem, researchers have done a lot of meaningful work and developed several distinctive methods. However, one of the common approaches to calculate the fluid viscosity is using the Green-Kubo formula by considering all the fluid molecules in nanospace, inevitably causing the involvement of the frictional interaction between fluid and the wall into the fluid viscosity.

Hierarchical thermal transport in nanoconfined water.

The structure of nanoconfined fluids is particularly non-uniform owing to the wall interaction, resulting in the distinctive characteristic of thermal transport compared to bulk fluids. We present the molecular simulations on the thermal transport of water confined in nanochannels with a major investigation of its spatial distribution under the effects of wall interaction. The results show that the thermal conductivity of nanoconfined water is inhomogeneous and its layered distribution is very similar to the density profile.

Asymmetric Two-Layer Porous Membrane for Gas Separation.

We present that the porous two-layer membranes of graphene and hexagonal boron nitride (-BN) are promising for gas mixture separation. For the two-layer membranes, the mechanisms of the gas separation are (i) the different adsorption properties of gases on two membranes inducing a permeation flux difference from one side to the other and (ii) the asymmetric potential energy curves (potential energy of a gas molecule vs distance between the pore center and a gas molecule) of a two-layer membrane leading to a potential energy difference, which can affect gas permeation through the pore. As a concrete example, we explore the gas separation of CO and CH by the two-layer membrane using molecular dynamics simulations.

Nanoconfined Fluids: What Can We Expect from Them?

Nanoconfined fluids (NCFs), which are confined in nanospaces, exhibit distinctive nanoscale effects, including surface effects, small-size effects, quantum effects, and others. The continuous medium hypothesis in fluid mechanics is not valid in this context because of the comparable characteristic length of spaces and molecular mean free path, and accordingly, the classical continuum theories developed for the bulk fluids usually cannot describe the mass and energy transport of NCFs. In this Perspective, we summarize the nanoscale effects on the thermodynamics, mass transport, flow dynamics, heat transfer, phase change, and energy transport of NCFs and highlight the related representative works.

Effects of Molecular Chain Length on the Contact Line Movement in Water/-Alkane/Solid Systems.

The movement of the contact line in liquid-liquid-solid systems is a major phenomenon in natural and industrial processes. In particular, -alkanes are widely occurring in the oil, soil pollution, and chemical industries, yet there is little knowledge on the effects of molecular chain length on the contact line movement. Here, we studied the effects of molecular chain length on the contact line movement in water/-alkane/solid systems with different surface wettabilities.

Evidence for water ridges at oil-water interfaces: implications for ion transport.

Understanding ion transport across interfaces is of fundamental importance in many processes such as liquid-liquid extraction, phase transfer catalysis, enhanced oil recovery and emulsion stabilisation. However, the factors that control ion transport across interfaces are poorly known due to a lack of knowledge of structural changes at interfaces. We studied here the effects of ionic concentration and external force on the transport of ions across the decane-water interface using classical molecular dynamics simulations.

Selective Molecular Sieving through a Large Graphene Nanopore with Surface Charges.

The precise control of the pore sizes at an atomic level has proved to be the biggest challenge of all for nanoporous graphene membranes for gas separation. Here, we propose a simple method to realize the selective molecular sieving through originally nonselective graphene nanopores by adding charges on the graphene surfaces. Molecular dynamic simulations show that the CO/N selectivity of the graphene nanopore with a diameter of 0.

A Functional Allele of Regulates Fruit Length through Repressing and Inhibiting Auxin Transport in Cucumber.

Fruit length is a prominent agricultural trait during cucumber () domestication and diversifying selection; however, the regulatory mechanisms of fruit elongation remain elusive. We identified two alleles of the ()-like MADS-box gene with 3393 Single Nucleotide Polymorphism variation among 150 cucumber lines. Whereas was specifically enriched in the long-fruited East Asian type cucumbers (China and Japan), the allele was randomly distributed in cucumber populations, including wild and semiwild cucumbers.

Moving mechanisms of the three-phase contact line in a water-decane-silica system.

The movement of the three-phase contact line with chain molecules in the liquid phase displays more complex mechanisms compared to those in the usual liquid-liquid-solid systems and even to the gas-liquid-solid systems controlled by the traditional single-molecule adsorption-desorption mechanisms. By introducing decane molecules with chain structures, we demonstrate from molecular dynamics insights that the moving mechanism of the contact line in a water-decane-silica system is totally different from traditional mechanisms. Three different wettability-related moving mechanisms including "Roll up", "Piston" and "Shear" are revealed corresponding to the hydrophilic, intermediate and hydrophobic three-phase wettability, respectively.

Nanoparticle-induced ion-sensitive reduction in decane-water interfacial tension.

The synergistic effect of ions and nanoparticles on the interfacial tension is of great significance for extensive applications in interface-related industrial processes. However, its mechanisms are still unclear owing to a lack of understanding on the interaction between nanoparticles/ions at the interface. Here, we employ the molecular dynamics method to explore the synergistic effect of ions and nanoparticles on reducing the decane-water interfacial tension and reveal the dominant role of the three-phase contact angle and the interaction between nanoparticles.

Oil Contact Angles in a Water-Decane-Silicon Dioxide System: Effects of Surface Charge.

Oil wettability in the water-oil-rock systems is very sensitive to the evolution of surface charges on the rock surfaces induced by the adsorption of ions and other chemical agents in water flooding. Through a set of large-scale molecular dynamics simulations, we reveal the effects of surface charge on the oil contact angles in an ideal water-decane-silicon dioxide system. The results show that the contact angles of oil nano-droplets have a great dependence on the surface charges.

Molecular Dynamics Study on the Effect of Surface Hydroxyl Groups on Three-Phase Wettability in Oil-Water-Graphite Systems.

In this paper, a hydroxylated graphite surface is generated as a hydrophilic oleophobic material for the application of oil-water separation, and the effects of hydroxyl density on the three-phase wettability are studied in oil-water-graphite systems. We analyze the adsorption of water molecules on the hydroxylated surfaces and obtain the relationship between water-oil-solid interfacial properties and the hydroxyl density, which results from the synthetic effects of the orientation of molecules and hydrogen bonds. With the increase of hydroxyl density, the water-solid contact angle first decreases rapidly, and then remains constant.

Ionic hydration-induced evolution of decane-water interfacial tension.

Building a connection between the variations in interfacial tension and the microstructure of the oil-water interface is still very challenging. Here, we employ a molecular dynamics method to study the effect of monovalent ions on the decane-water interfacial tension and reveal the relationship between ionic hydration and the variation of interfacial tension. Our results indicate that interfacial tension presents a non-monotonic dependence on the ionic concentrations owing to the distinctive adsorption characteristics of ions.