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In this work, we investigate the effect of the hydrodynamic wall–fluid friction in electro-osmotic flows. First, we present the solution to the electro-hydrodynamic equation for the electro-osmotic velocity profile, which is derived for an ionic system composed of cations immersed in uncharged solvent particles. The system (solution and walls) is kept electrically neutral using negatively charged walls and will here be referred to as a "counterion-only" system. The theory predicts the existence of a counterion concentration that results in maximum electro-osmotic flow rate, but only if the wall–fluid friction, or equivalently the slip length, is correlated with the system electrostatic screening length. Through equilibrium molecular dynamics simulations, we precisely determine the hydrodynamic slip from the wall–fluid friction, and then, this is used as input to the theoretical predictions. Comparison between the theory and independent non-equilibrium molecular dynamics simulation data confirms the existence of the maximum. In addition, we find that standard hydrodynamic theory quantitatively agrees with the simulation results for charged nanoscale systems for sufficiently small charge densities and ion charges, if the correct slip boundaries are applied. [ABSTRACT FROM AUTHOR]

1H spin–lattice relaxation experiments have been performed for ionic liquid–polymer gel membranes, including 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) with different proportions. The experiments have been performed in a broad range of resonance frequencies (from about 5 Hz to 40 MHz) vs temperature and complemented with analogous studies for [BMIM][BF4] in bulk as a reference. A model of the relaxation processes in the membranes has been proposed. The model includes two relaxation contributions. One of them corresponds to the concept of restricted, two-dimensional translation diffusion with a residence lifetime, while the second one has the form characteristic of polymers (mathematically similar to the limiting behavior of two-dimensional translation diffusion with a very long residence lifetime). The extensive dataset has been consistently interpreted in terms of the model, revealing two dynamical processes on the time scales of 10−7 s (for the second relaxation contribution) and 10−9 s (for the first one). The relationship of these relaxation contributions to the motion of the polymer or ionic liquid–polymer complexes and to the translation diffusion of BMIM cations in the matrix has been discussed. [ABSTRACT FROM AUTHOR]

The fragmentation of ion clusters within the accelerating fields of ionic liquid ion sources (ILISs) is well documented and degrades ILIS performance and lifetime. Some of the most popular ILIS liquids, such as EMI-BF4 (1-Ethyl-3-methylimidazolium tetrafluoroborate) and EMI-Im (1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide), emit clusters with lifetimes as low as ∼1 ns. Studies of fragmentation within the accelerating field typically rely on measuring the plume energy distribution averaged over all plume species and comparing those measurements with numerical simulations to estimate ion cluster lifetimes. Here, for the first time, we estimate EMI-BF4 cluster lifetimes by analyzing the energy distributions of individual plume species. We use this novel analysis method to estimate mean lifetimes of positive EMI-BF4 ion clusters from previously published experimental data. We find that the mean lifetime ranges from τ = 3.7 ns to τ = 124 ns for [ EM I + ] [ EMI - B F 4 ] dimers and ranges from τ = 1.5 ns to τ = 23 ns for [ EM I + ] [ EMI - B F 4 ] 2 trimers. Fitting those data to an analytical fragmentation model, we estimate the binding energy and temperature as Δ G S 0 = 0.49 eV and T = 394 K for dimers and Δ G S 0 = 0.40 eV and T = 365 K for trimers. Comparing our results with previous studies supports the conclusion that clusters are emitted with a wide distribution of internal energies, contrary to the common assumption of single internal energy for each species. [ABSTRACT FROM AUTHOR]

Dissociative electron attachment rate constants have been measured for Cr(CO)6 under thermal conditions, 296–400 K, yielding Cr(CO)5− product. At 296 K, 2.92 ± 0.70 cm3 s−1 was measured and a small decrease with temperature was observed (2.72 ± 0.70 cm3 s−1 at 400 K). We additionally determined the cation products of Ar+ reacting with Cr(CO)6. [ABSTRACT FROM AUTHOR]

To elucidate the epitaxial strain effect over a wide range of lattice mismatch, we investigated the structures of ∼ 25 nm thick LaNiO 3 films grown on the pseudocubic (001) surfaces of three different substrates, namely, LaAlO 3 (LAO), SrTiO 3 (STO), and DyScO 3 (DSO). Such structural information had been inferred from the intensities of a small number of Bragg reflections that relate to the NiO 6 octahedral tilting in previous studies. Here, we measured more than 100 reciprocal lattice points to derive reliable structural information. The procedure of ordinary crystal structure analysis is hampered by the multidomain structure and limited volume of measurable reciprocal space, both caused by a huge, highly symmetric substrate. To overcome this difficulty, we employed the Bayesian inference to obtain the detailed atomic positions in film samples. Octahedral tilting about the c axis was dominant for the compressively strained film grown on LAO, whereas tilting about the a and b axes was dominant for the tensile strained films grown on STO and DSO. The film lattice parameters of the samples grown on STO and DSO were nearly identical, whereas additional twofold lattice modulation, including cation displacement, was only observed in the latter. [ABSTRACT FROM AUTHOR]

To efficiently generate H − ions from positive atomic or molecular hydrogen beams injected onto a solid surface, it has been suggested to use a material with a low-work function as the target material. However, it is not clear under what conditions the most efficient H − production is realized for incident beam parameters or reflection angles. Therefore, we studied the interaction between low-energy atomic and molecular hydrogen beams (less than 1 keV/nucleon) with a low-work function electride 12CaO ⋅ 7 A l 2 O 3 (C12A7). The production ratio of H − to H + ions from the C12A7 electride was much higher than Mo targets with higher work functions, especially at smaller incident and smaller reflection angles. The H − to H + production ratio slightly increased as the incident energies were decreased, but there was no significant difference between the electride and Mo targets. These results indicate that smaller incident angles and lower beam energies of the incident hydrogen beam are favorable for the enhancement of the production ratio of H − to H + ions in C12A7. The higher production ratio appeared at the vertical beam energies less than on the order of 100 eV, where quantum mechanical processes may become important. [ABSTRACT FROM AUTHOR]

The mutual synergistic regulation of the multi-functional sites on a single receptor molecule for ion-binding/recognition is vital for the new receptor design and needs to be well explored from experiment and theory. In this work, a new macrocyclic ion receptor (BEBUR) with three functional zones, including two ether holes and one biurea groups, is designed expecting to mutually enhance the ion-binding performance. The binding behaviors of BEBUR mainly for Cl− and Cs+ are deeply investigated by using density functional theoretical calculations. It is found that Cl−/Cs+ binding can be mutually enhanced and synergistically regulated via corresponding conformational changes of the receptor, well reflecting an electrical complementary matching and mutual reinforcement effect. Moreover, solvent effect calculations indicate that BEBUR may be an excellent candidate structure for Cl−-binding with the enhancement of counter ion (Cs+) in water and toluene. In addition, visualization of intermolecular noncovalent interaction is used for analysis on the nature of the binding interactions between receptor and ions. [ABSTRACT FROM AUTHOR]

Hydrated cation–π interactions at liquid–solid interfaces between hydrated cations and aromatic ring structures of carbon-based materials are pivotal in many material, biological, and chemical processes, and water serves as a crucial mediator in these interactions. However, a full understanding of the hydrated cation–π interactions between hydrated alkaline earth cations and aromatic ring structures, such as graphene remains elusive. Here, we present a molecular picture of hydrated cation–π interactions for Mg2+ and Ca2+ by using the density functional theory methods. Theoretical results show that the graphene sheet can distort the hydration shell of the hydrated Ca2+ to interact with Ca2+ directly, which is water–cation–π interactions. In contrast, the hydration shell of the hydrated Mg2+ is quite stable and the graphene sheet interacts with Mg2+ indirectly, mediated by water molecules, which is the cation–water–π interactions. These results lead to the anomalous order of adsorption energies for these alkaline earth cations, with hydrated Mg2+–π < hydrated Ca2+–π when the number of water molecules is large (n ≥ 6), contrary to the order observed for cation–π interactions in the absence of water molecules (n = 0). The behavior of hydrated alkaline earth cations adsorbed on a graphene surface is mainly attributed to the competition between the cation–π interactions and hydration effects. These findings provide valuable details of the structures and the adsorption energy of hydrated alkaline earth cations adsorbed onto the graphene surface. [ABSTRACT FROM AUTHOR]

Viscosity, or the thickness, of aerosols plays a key role in atmospheric processes like ice formation, water absorption, and heterogeneous kinetics. However, the viscosity of sea spray aerosols (SSA) has not been widely studied. This research explored the relationship between particle size and viscosity of authentic SSA particles through particle bounce, atomic force microscopy analysis, and predictive viscosity modeling from molecular composition. The study found that 40 nm SSA particles had estimated viscosities around 104 Pa·s and bounce fractions three times higher than 100 and 200 nm particles with less than 102 Pa·s at a relative humidity (RH) of 60%. Additional studies revealed the Kelvin effect and particle density, influenced by particle size, have a greater impact on size-dependent bounce fractions than changes in RH across impactor stages. While changes in the level of surfactants can impact particle bounce, the increased viscosity in smaller SSA is attributed to the formation of gel-like phase states caused by cation-organic cross-links between divalent calcium ions and organic anions enriched in the smaller particles. This work shows the smallest gel-like SSA particles observed in the field are highly viscous, which has implications for cloud formation, secondary aerosol growth, and pollutant transport in coastal environments.

The plasma-wall transition is investigated by a one-dimensional steady-state multifluid model, which was presented in detail in Part I [T. Gyergyek et al., AIP Adv. 14, 045201 (2024)]. In this work, the plasma-wall transition is analyzed for the case where the plasma consists of singly charged positive ions, electrons, and singly charged negative ions. When the temperature and initial density of the negative ions are varied, a transition between two types of solutions of the model is observed. We call them the low and high solution, with respect to the absolute value of the potential drop. When the density and temperature of the negative ions are above a critical value, the low solution is observed. As the mass of the positive ions increases, these critical values also increase, but only until the ion mass is below about 1000 electron masses. With larger ion masses, the critical density of the negative ions and the temperature no longer change. In the low solution, the potential drop in front of the sheath is determined by the negative ions and is smaller in absolute terms than in the case of the high solution, where the potential drop in front of the sheath is determined by the electrons. If the problem is analyzed on the pre-sheath scale, the transition between the low and high solution is very sharp. However, when the neutrality condition is replaced by the Poisson equation, this transition becomes blurred and the solutions of the model equations exhibit oscillations. The role of the smallness parameter is highlighted. It is shown how the initial electric field is determined. Deviation of the negative ion density profile from the Boltzmann relation is discussed. [ABSTRACT FROM AUTHOR]

The observed metastable characteristics of cation vacancies in Ga2O3 have prompted a wider search for such systems. In this Perspective, we consider a number of defect systems as candidates for metastability. Some of these are already known to have this property, while for others, this suggestion is new. The examples discussed here are but a sampling of a huge number of systems, and these are used to emphasize that the metastability of defect structures is both common and important; it may yield (for example) split vacancy equilibrium configurations and, hence, should be considered in developing defect models and in analyzing their properties. [ABSTRACT FROM AUTHOR]

The rates of many electrocatalytic reactions can be strongly affected by the structure and dynamics of the electrochemical double layer, which in turn can be tuned by the concentration and identity of the supporting electrolyte's cation. The effect of cations on an electrocatalytic process depends on a complex interplay between electrolyte components, electrode material and surface structure, applied electrode potential, and reaction intermediates. Although cation effects remain insufficiently understood, the principal mechanisms underlying cation-dependent reactivity and selectivity are beginning to emerge. In this Perspective, we summarize and critically examine recent advances in this area in the context of the hydrogen evolution reaction (HER) and CO2-to-CO conversion, which are among the most intensively studied and promising electrocatalytic reactions for the sustainable production of commodity chemicals and fuels. Improving the kinetics of the HER in base and enabling energetically efficient and selective CO2 reduction at low pH are key challenges in electrocatalysis. The physical insights from the recent literature illustrate how cation effects can be utilized to help achieve these goals and to steer other electrocatalytic processes of technological relevance. [ABSTRACT FROM AUTHOR]

Hot carrier solar cells could offer a solution to achieve high efficiency solar cells. Due to the hot-phonon bottleneck in perovskites, the hot carrier lifetime could reach hundreds of ps. Such that exploring perovskites could be a good way to promote hot carrier technology. With the incorporation of large organic cations, the hot carrier lifetime can be improved. By using ultrafast transient spectroscopy, the hot carrier relaxation and extraction kinetics are measured. From the transient kinetics, 2-phenyl-acetamidine cation based perovskites exhibit the highest initial carrier temperature, longest carrier relaxation, and slowest hot carrier relaxation. Such superior behavior could be attributed to reduced electron–phonon coupling induced by lattice strain, which is a result of the large organic cation and also a possible surface electronic state change. Our discovery exhibits the potential to use large organic cations for the use of hot carrier perovskite solar cells. [ABSTRACT FROM AUTHOR]

The reaction of Ag+ with Ru3(CO)12 in a CO atmosphere under concommittant irradiation with UV-light yields a salt of the metal-only Lewis-pair [Ag{Ru(CO)5}2]+. Switching the silver cation for a more process-selective deelectronator yields a salt of the homoleptic transition metal carbonyl cation [Ru2(CO)10]2+, which fills the gap between the known cations [Ru(CO)6]2+ and [Ru3(CO)14]2+. The amount of π-backdonation in this series was studied by a combination of vibrational spectroscopy and computed relaxed force constants. [ABSTRACT FROM AUTHOR]

Rationale: The chemical composition of the new compound aloe capsule (NCAC) has not been fully elucidated to date, which poses challenges for pharmacology, scientific, and rational drug use. In this study, a rapid and sensitive method was established to comprehensively study the constituents in the NCAC. The contents of the NCAC were analyzed by UPLC‐Q‐Orbitrap‐MS and data postprocessing technology. Methods: Firstly, the extract was separated by UPLC system, and the fragment information was obtained under positive and negative ions and then compared with the characteristic fragments described in the literature, so as to achieve the purpose of rapid identification of the compound of NCAC. Results: A total of 56 compounds including 21 chromones, 6 pyranones, 7 anthraquinones, 7 anthrone, 5 alkaloids, 4 amino acids, and 6 other components were detected in NCAC by comparing the retention time and mass spectrometry information and retrieving the reference literature. Conclusions: The UPLC‐Q‐Orbitrap‐MS method was developed and utilized successfully to identify the major constituents in NCAC and would be helpful for improving the quality control standard of NCAC. [ABSTRACT FROM AUTHOR]

The reaction of Ag+ with Ru3(CO)12 in a CO atmosphere under concommittant irradiation with UV-light yields a salt of the metal-only Lewis-pair [Ag{Ru(CO)5}2]+. Switching the silver cation for a more process-selective deelectronator yields a salt of the homoleptic transition metal carbonyl cation [Ru2(CO)10]2+, which fills the gap between the known cations [Ru(CO)6]2+ and [Ru3(CO)14]2+. The amount of π-backdonation in this series was studied by a combination of vibrational spectroscopy and computed relaxed force constants. [ABSTRACT FROM AUTHOR]

Illegal additives such as oxyphenisatine and its esters are prevalent in the slimming food industry, necessitating a robust analytical method for their detection. This study presents a novel UPLC-MS/MS method for the rapid and accurate quantification of total oxyphenisatine levels in fermented green plum, following hydrolysis of its esters. An efficient ultrasonic extraction with a methanol and 0.1 mol/L NaOH mixture (5:5, v/v) was optimised to hydrolyse esters to oxyphenisatine within 18 min. Chromatographic separation was conducted on a C18 column (Waters Acquity UPLC BEH, 2.1 × 100 mm, 1.7 μm) with a mobile phase of 5 mmol/L ammonium acetate and acetonitrile under gradient elution at a flow rate of 0.3 mL/min. The method demonstrated linearity (r2 > 0.999) over 0.1–500 µg/L, with a LOD of 10 µg/kg and LOQ of 30 µg/kg. Quantitative analysis employed positive ion multi-response monitoring and external standardisation, achieving recoveries of 92.4–97.0% and RSDs of 2.9–4.1%. Application to ten real samples gave a 90% detection rate, with measured values closely aligning with theoretical predictions (−11.3 to 13.2% relative difference) and oxyphenisatine content ranging from 159 µg/kg to 452 mg/kg. This UPLC-MS/MS method provides a reliable and efficient tool for monitoring the presence of oxyphenisatine and its derivatives in the context of food safety. [ABSTRACT FROM AUTHOR]

Rationale: Flavonoid C‐glycosides have a wide range of pharmacological activities. However, there are few mass spectrometric research on C,O‐disaccharide flavonoid C‐glycosides and di‐C,O‐saccharide flavonoid C‐glycosides. Their low‐energy collision‐induced dissociation (ESI‐CID‐MS/MS) fragmentation pattern and differences have not been reported, and the fragment ion library is incomplete. Therefore, it was essential to elucidate the fragmentation patterns of disaccharide flavonoid C‐glycosides, which is described in this study. Methods: Four disaccharide flavonoid C‐glycosides such as vitexin‐4″‐O‐glucoside were analyzed by ultra‐performance liquid chromatography‐triple quadrupole tandem mass spectrometer (UPLC‐MS/MS) using electrospray ionization (ESI) in both positive and negative ion modes. Each ion and its proposed fragmentation pathways of the four disaccharide flavonoid C‐glycosides were analyzed comprehensively. Finally, ultra‐high performance liquid chromatography‐quadrupole time‐of‐flight mass spectrometry (UPLC‐Q‐TOF‐MS/MS) and the established fragmentation patterns have been used to identify disaccharide flavonoid C‐glycosides in Odontosoria Chinensis. Results: The fragmentation pathways of C,O‐disaccharide flavonoid C‐glycosides and di‐C,O‐saccharide flavonoid C‐glycosides are similar. They both have the mass spectrometric characteristics of O‐glycoside and C‐glycoside. Product ions after mixed pathways of neutral fragments such as saccharide ring fragment, O‐glycosides, H2O, and CH2O elimination appeared in both types of flavonoid C‐glycosides, but their relative abundances are significantly different. According to the established fragmentation patterns, di‐C,O‐saccharide flavonoid glycosides were also found in Odontosoria chinensis. Conclusion: The fragment ions at m/z 431, 413, 341, 311, 293, and 282 in negative ion mode and m/z 293, 282, 577, 559, 541, 523, 529, and 499 in positive ion mode can serves as the main characteristics for identifying C,O‐disaccharide flavonoid C‐glycosides and di‐C,O‐saccharide flavonoid C‐glycosides. [ABSTRACT FROM AUTHOR]

The Selectivity Filter (SF) in tetrameric K+ channels, has a highly conserved sequence, TVGYG, at the extracellular entry to the channel pore region. There, the backbone carbonyl oxygens from the SF residues, create a stack of K+ binding sites where dehydrated K+ binds to induce a conductive conformation of the SF. This increases intersubunit interactions and confers a higher stability to the channel against thermal denaturation. Indeed, the fit of dehydrated K+ to its binding sites is fundamental to define K+ selectivity, an important feature of these channels. Nonetheless, the SF conformation can be modified by different effector molecules. Such conformational plasticity opposes selectivity, as the SF departs from the "induced-fit" conformation required for K+ recognition. Here we studied the KirBac1.1 channel, a prokaryotic analog of inwardly rectifying K+ channels, confronted to permeant (K+) and non-permeant (Na+) cations. This channel is pH-dependent and transits from the open state at neutral pH to the closed state at acidic pH. KirBac1.1 has the orthodox TVGYG sequence at the SF and thus, its behavior should resemble that of K+-selective channels. However, we found that when at neutral pH, KirBac1.1 is only partly K+ selective and permeates this ion causing the characteristic "induced-fit" phenomenon in the SF conformation. However, it also conducts Na+ with a mechanism of ion passage reminiscent of Na+ channels, i.e., through a wide-open pore, without increasing intersubunit interactions within the tetrameric channel. Conversely, when at acidic pH, the channel completely loses selectivity and conducts both K+ and Na+ similarly, increasing intersubunit interactions through an apparent "induced-fit"-like mechanism for the two ions. These observations underline that KirBac1.1 SF is able to adopt different conformations leading to changes in selectivity and in the mechanism of ion passage. [ABSTRACT FROM AUTHOR]

Mass spectrometry imaging (MSI) is a powerful tool for detecting lipids in tissue sections, with matrix‐assisted laser desorption/ionization (MALDI) and desorption electrospray ionization (DESI) as its key ionization techniques. In this study, we examine how MALDI compares with state‐of‐the‐art DESI ionization in identifying lipids in heterogeneous samples, specifically atherosclerotic plaques. Carotid plaques (n = 4) from patients undergoing endarterectomy were snap‐frozen, stored at −80°C, and then sectioned for MSI analysis and H&E staining. Measurements were conducted using a SYNAPT XS mass spectrometer in positive ion mode, employing MALDI with a 2,5‐dihydroxybenzoic acid (DHB) matrix and DESI with a methanol: water (98:2) (v/v) solvent. Our comparison covered spectral profiles, sensitivity, and image quality generated by these two techniques. We found that both MALDI and DESI are highly suitable techniques for detecting a wide range of lipids in atherosclerotic plaque sections. DESI‐MSI exhibited higher ion counts for most lipid classes than MALDI‐MSI and provided sharper images. MALDI detected larger amounts of ceramide and hexosylceramide species, possibly due to its efficient generation of dehydrated ions. In contrast, DESI showed greater peak intensities of cholesteryl ester and triacylglyceride species than MALDI, consistent with reduced fragmentation. These findings establish the relative merits of DESI and MALDI and demonstrate their complementarity as techniques for lipid research in MSI. [ABSTRACT FROM AUTHOR]

Phosphazenium cations were first characterized 60 years ago and yet little is known of their reactivity. The bidentate phosphonium dicationic salts [(C6H4)(PPh2F)2][B(C6F5)4]22 and [(C6H4)(PPh2Cl)2][Cl]23 were prepared. Reaction of 2 with (Me3Si)2NMe gave the phosphazenium dication [(C6H4)(PPh2)2(μ-NMe)][B(C6F5)4]24, while reaction of 3 with two equivalents of Me2N(SiMe3) gave the related dication [(C6H4)(PPh2NMe2)2][Cl]25. Compound 3 also reacted with (Me3Si)2NH affording the monocationic salt [(C6H4)(PPh2)2(μ-N)]Cl 6, with the liberation of HCl. Interestingly 4 reacted with [nBu4N]Cl generating the related salt [(C6H4)(PPh2)2(μ-N)][B(C6F5)4] 6′ with concurrent formation of MeCl. This reactivity was extended to [(C2H4)(PPh2F)2][B(C6F5)4]27 which afforded [(C2H4)(PPh2)2(μ-NR)][B(C6F5)4]2 (R = Me 8, CH2CHCH29, CH2Ph 10) upon reaction with (Me3Si)2NR. These dications were shown to react with [nBu4N]Cl affording [(CH2PPh2)2(μ-N)][B(C6F5)4] 11 and the corresponding alkyl-chloride. The mechanism of these N–C bond cleavage reactions is considered [ABSTRACT FROM AUTHOR]

The pyrrolyl cation is a 4π electron ring system which is anti-aromatic and unstable. This work reports an experimental procedure to obtain stable pyrrolyl cations. Electron donation from N-heterocyclic carbenes makes the ring stable by converting a 4p electron ring system into a 6p electron ring system. [ABSTRACT FROM AUTHOR]

The Bi2Se3–In2Se3 layered system has garnered significant attention and extensive research due to its versatile properties, yet its structural properties and phase stability remain elusive. Here, using first-principles calculations with van der Waals interactions, we systematically study the phase stability and transition behavior of (BixIn1−x)2Se3 alloys. Our results reveal a contrasting stability profile between Bi2Se3 and In2Se3, with the former exhibiting a distinct preference for the β phase over the α phase, while the latter shows similar stabilities in both phases, thus partially addressing previously reported ground-state inconsistencies. Exploring composition–structure relationships, we demonstrate that Bi incorporation in low concentrations stabilizes the β phase, consistent with early experimental observations. Further analysis based on the cation orbital properties indicates that the preference of Bi for octahedral sites over tetrahedral ones drives the small critical composition for the α→β phase transition. This work enhances our understanding of phase stability in (BixIn1−x)2Se3 alloys, providing insights for future design of monophasic materials and advanced applications. [ABSTRACT FROM AUTHOR]

ATP-activated P2X3 receptors play a pivotal role in chronic cough, affecting more than 10% of the population. Despite the challenges posed by the highly conserved structure of P2X receptors, efforts to develop selective drugs targeting P2X3 have led to the development of camlipixant, a potent, selective P2X3 antagonist. However, the mechanisms of receptor desensitization, ion permeation, and structural basis of camlipixant binding to P2X3 remain unclear. Here, we report a cryo-EM structure of camlipixant-bound P2X3, revealing a previously undiscovered selective drug-binding site in the receptor. Our findings also demonstrate that conformational changes in the upper body domain, including the turret and camlipixantbinding pocket, play a critical role: turret opening facilitates P2X3 channel closure to a radius of 0.7 Å, hindering cation transfer, whereas turret closure leads to channel opening. Structural and functional studies combined with molecular dynamics simulations provide a comprehensive understanding of camlipixant's selective inhibition of P2X3, offering a foundation for future drug development targeting this receptor. [ABSTRACT FROM AUTHOR]

Heterometallic cluster‐based materials offer the potential to incorporate multiple functionalities, leveraging the aggregation effects of clusters and translating this heterogeneity and complexity into unexpected properties that are more than just the sum of their components. However, the rational construction of heterometallic cluster‐based materials remains challenging due to the complexity of metal cation coordination and structural unpredictability. This minireview provides insights into a general synthetic strategy based on Hard and Soft Acids and Bases (HSAB) theory, summarizing its advantages in the designed synthesis of discrete heterometallic clusters (intracluster assembly) and infinite heterometallic cluster‐based materials (intercluster assembly). Furthermore, it emphasizes the potential to exploit the intrinsic properties of mixed components to achieve breakthroughs across a broad range of applications. The insights from this review are expected to drive the progress of heterometallic cluster‐based materials in a controllable and predictable manner. [ABSTRACT FROM AUTHOR]

The investigation of unsaturated or π‐conjugated hydrocarbons, particularly within the macrocyclic framework, has garnered significant interest due to their fundamental properties and practical applications. This research focuses on the synthesis and characterization of a novel stable dicarbatriphyrin(2.1.1) which was constructed by amending the [14]triphyrin(2.1.1) framework by, replacing two pyrrole rings with meta‐connected phenyl rings and introducing an o‐benzene bridge at the C2 position. The structural modification resulted in a saddle‐shaped macrocyclic core with negative Gaussian curvature, as confirmed by crystal structure analysis. This unique molecular topology offers acumens into the structure‐property relationships in the curved locally π‐conjugated contracted porphyrinoids. The macrocycle exhibits fluorescent emission in solution, which is selectively quenched by Fe(III) ions, highlighting its potential as a chemosensor for Fe(III) cations. Additionally, the formation of carbacalix[1]phyrin(2.1.1), a phlorin analogue of dicarbatriphyrin(2.1.1), which exhibits a chair conformation in contrast to the saddle‐shaped structure of its oxidized counterpart. Remarkably, the emergence of a mono‐pyrrolic calixbenziphyrin marks an unprecedented advancement in the field of calixphyrin chemistry. Moreover, theoretical studies provide strong support for the experimental findings, reinforcing the conclusions drawn from the structural and functional analyses. [ABSTRACT FROM AUTHOR]

When a small atom is induced into a larger lattice, new phonon scattering modes are aroused and thermal conductivity is significantly reduced by increased anharmonicity. This effect, called "rattling," has been reported in pyrochlores and some cage compounds, but not in α‐SiAlON. In this study, we reveal that in (Yb+Ca) co‐doped α‐SiAlON ceramics (YbaCabSi7.5Al4.5O1.5N14.5, x = a/[a+b]), the rattling effect plays a crucial role in reducing thermal conductivity. Samples with different Yb/Ca ratios (x = 0, 0.1, 0.2, 0.3..., 1.0) were sintered by spark plasma sintering (SPS) at 1600°C and their thermal diffusivity/conductivity were measured by the laser‐flash method. We found that substituting Ca2+ with smaller Yb3+ cations in Ca‐α‐SiAlON caused significant reduction in thermal conductivity. On the contrary, substituting Yb3+ with larger Ca2+ cations in Yb‐α‐SiAlON caused only slight reduction in thermal conductivity. A lowest thermal conductivity of 3.3 W/(m·K) was achieved, when x = 0.3 rather than x = 0.5 or 0.7. Further analysis of phonon scattering intensity confirmed that both intrinsic and extrinsic scatterings are enhanced in the sample of x = 0.3. This study demonstrates that by utilization of the rattling effect, α‐SiAlON, well‐known for its excellent mechanical properties, can be tuned to exhibit low thermal conductivity comparable to that of La2Zr2O7 and 8YSZ. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The observation of high-Tc superconductivity (HTSC) in concomitant with pressure-induced orthorhombic-tetragonal structural transition in bilayer La3Ni2O7 has sparked hopes of achieving HTSC by stabilizing the tetragonal phase at ambient pressure. Chemical pressure, introduced by replacing La3+ with smaller rare-earth R3+ has been considered as a potential route. However, our experimental and theoretical investigation reveals that such substitutions, despite causing lattice contraction, actually produce stronger orthorhombic distortions, requiring higher pressures for the structural transition. A linear extrapolation of Pc versus the average size of A-site cations (A>), yields a putative critical value of A>c ≈ 1.23 Å for Pc ≈ 1 bar. The negative correlation between Pc and A> indicates that replacing La3+ with smaller R3+ ions is unlikely to reduce Pc to ambient pressure. Instead, substituting La3+ with larger cations like Sr2+ or Ba2+ might be a feasible approach. Our results provide guidance for realizing ambient-pressure HTSC in bilayer nickelates. [ABSTRACT FROM AUTHOR]

Complex interactions between cellulose molecules and small molecules of deep eutectic solvents (DESs) can lead to dramatic changes in the structure of the hydrogen bond network in cellulose. However, the molecular and ionic evolution mechanism of DESs on cellulose nanofibrillation is still unclear. In this study, the mechanism and the critical role of ions in DESs on cellulose nanofibrillation were investigated. The results showed that cellulose nanofibers (CNFs) with a diameter of less than 200 nm could be prepared directly using DES consisting of lactic acid (LA) and chloride, e.g., LA/ammonium chloride (NH4Cl) or LA/dodecyltrimethylammonium chloride (DTAC). Using LA/Zinc chloride (ZnCl2), CNFs with a diameter of less than 100 nm can be prepared. The Kamlet-Abboud-Taft parameters (KAT value) showed that DESs containing LA had higher hydrogen bond acidity (α) than other systems (such as ethylene glycol and urea) without LA, which provided more active protons to improve the proton mobility in the cellulose nanofibrillation. Also, DESs composed of LA and Cl− had high hydrogen bond alkalinity (β), which led to great changes in the original hydrogen bond network of cellulose and the formation of a new hydrogen bond structure, thereby easing the dissolution of the cellulose. Thus, the cellulose hydroxy groups could be esterified by the LA under high-temperature moistening conditions, and the CNFs prepared by the DES system containing LA and Cl− had the highest degree of substitution (DS) (up to 0.73 in LA/ZnCl2 system) after high-temperature moistening. [ABSTRACT FROM AUTHOR]

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The present study examined the vitrification of spent ion exchange (IEX) resins in a borosilicate glass matrix on the laboratory scale. For this purpose, the simulated spent IEX resin waste prepared by doping non-radioactive cobalt and cesium elements on a combination of cationic and anionic resins was employed. For glass wasteform preparation, heat-treated (at 150 °C) spent IEX resin was mixed with borosilicate glass ferrite in the range of 20-40 weight percent and then melted at 1200 °C. To evaluate the prepared glass wasteforms, their volume reduction ratio (VRR) and chemical stability were investigated. According to the obtained results, with the increase in the spent IEX resin loading, the volume reduction ratio of the final wasteform increases. However, in the samples with spent IEX resins loading higher than 30 wt.%, phase separation (white color containing insoluble sulfate) was observed on the surface of the glass. Investigations showed that glass wasteform containing 30 wt.% spent IEX resins provides the best conditions for waste immobilization. The relative volume reduction ratio of this sample was measured as 86.61%. The normalized leaching rate of cesium and cobalt from this wasteform was calculated as 7.43 x 10-5 and 6.93 x 10-5 g.m-2.day-1, respectively, using the PCT method. [ABSTRACT FROM AUTHOR]

Dion–Jacobson‐type 2D halide perovskites (DJPs) present an ideal alternative to their 3D counterparts due to their superior stability and exceptional optoelectronic properties. Despite the numerous DJPs proposed in recent years, the impact of different spacer cations on DJPs remains unclear. This understanding is crucial for researchers to select suitable materials and is an urgent requirement for the development of higher‐performance DJPs‐based devices. In this study, the influence of the chain‐like spacer cations with varying branch chains and chain lengths is thoroughly examined using both theoretical and experimental methods. The findings reveal that spacer cations with high polarity components along the main chain direction enhance the stability and photoelectric properties of DJPs. Additionally, it is found that the chain length of the spacer cation plays a critical role. Chain lengths that are too long or too short can detrimentally affect the photoelectric performance and stability of DJPs. These insights will guide researchers in selecting suitable spacer cations and in innovating new types of DJPs. [ABSTRACT FROM AUTHOR]

Halogen‐bonding (XB) interactions have been extensively studied in the preparation of crystalline frameworks, yet porous 3D framework materials built on XBs remain elusive. The donor‐acceptor interactions are strengthened by use of anionic XB acceptors; however, the requisite charge‐balancing cations typically disrupt the framework and occupy potential void space. In this work, we prepare a tetratopic XB donor bearing a crown ether moiety for sodium cation sequestration. We show that when this ionpair receptor is crystallised with NaCl it gives a 3D framework that is porous to solvent and vapour, and undergoes single‐crystal‐to‐single‐crystal reactions. [ABSTRACT FROM AUTHOR]

Lithium‐excess cation disordered rocksalt (DRX) cathodes have gained wide attention because of their capability of delivering high energy densities solely relying on inexpensive and earth‐abundant transition metal (TM) species. To date, various strategies have been proposed for their intrinsic performance optimization, including designing high‐entropy compositions to suppress cation short‐range order (SRO), incorporating high Mn content to promote the in situ phase transformation to a partially‐disordered spinel phase (δ phase) or Cr doping to enhance the Li‐ion mobility; however, the compatibility of these strategies remains unexplored. In this study, the interplay among the three strategies is systematically investigated when applied concurrently via the design of a series of DRX cathode compounds. The findings demonstrate that compared to the other two strategies, DRX‐to‐δ phase transformation induced by high Mn content plays a more significant role in improving the electrochemical performance of DRX cathodes, which simultaneously elevates the capacity and cycle life. Cr or multi‐elemental doping will inevitably dilute the Mn concentration, limiting the performance enhancement. These insights ultimately contribute to the design of an optimal composition that combines high capacity and long cycle life. [ABSTRACT FROM AUTHOR]

Mulberry (Morus spp.) is an economically significant plant in the production of silk through feeding leaves to silkworm larvae. Traditional silkworm rearing is heavily labor-intensive, particularly in leaf collection, which leads to low efficiency and impedes the development of sericulture. Here, to assess the feasibility and effectiveness of a novel low-pruning mulberry cultivar, ZJ1, in the silkworm rearing industry, a comprehensive investigation integrating physiological, proteomic, and metabolomic analyses was conducted in comparison with the traditionally high-pruning cultivar, N14. The low-pruning mulberry variety ZJ1 exhibited a notable increase in annual leaf yield of 43.94%, along with a significant enrichment of serine and isoleucine contents, in contrast to those of the high-pruning variety N14. Through iTRAQ proteomics and LC-MS/MS metabolomics analyses, a total of 561 reduced and 803 increased differentially expressed proteins (DEPs), as well as 332 differential expressed metabolites (DEMs) in positive ions and 192 DEMs in negative ions, were identified in the ZJ1 group relative to the N14 group, respectively. The observed features in amino acid profiles and the enrichment of the sucrose-related metabolic pathway provided interesting insights for future endeavors in mulberry variety improvement and the optimization of silkworm diet formulations. Collectively, the low-pruning cultivar ZJ1, characterized by its rapid growth, high leaf productivity, and suitability for mechanized operations, is expected to be an efficient substitute in improving the future sericultural industry, especially in urbanized and industrialized regions. [ABSTRACT FROM AUTHOR]

Rational design of chiral two‐dimensional hybrid organic–inorganic perovskites is crucial to achieve chiroptoelecronic, spintronic, and ferroelectric applications. Here, an efficient way to manipulate the chiroptoelectronic activity of 2D lead iodide perovskites is reported by forming mixed chiral (R‐ or S‐methylbenzylammonium (R‐MBA+ or S‐MBA+)) and achiral (n‐butylammonium (nBA+)) cations in the organic layer. The strongest and flipped circular dichroism signals are observed in (R/S‐MBA0.5nBA0.5)2PbI4 films compared to (R/S‐MBA)2PbI4. Moreover, the (R/S‐MBA0.5nBA0.5)2PbI4 films exhibit pseudo‐symmetric, unchanged circularly polarized photoluminescence peak as temperature increases. First‐principles calculations reveal that mixed chiral–achiral cations enhance the asymmetric hydrogen‐bonding interaction between the organic and inorganic layers, causing more structural distortion, thus, larger spin‐polarized band‐splitting than pure chiral cations. Temperature‐dependent powder X‐ray diffraction and pair distribution function structure studies show the compressed intralayer lattice with enlarged interlayer spacing and increased local ordering. Overall, this work demonstrates a new method to tune chiral and chiroptoelectronic properties and reveals their atomic scale structural origins. [ABSTRACT FROM AUTHOR]

Cations in ionic liquids (ILs) are typically derived from ammonium or phosphonium structures with long alkyl chains, and it is well established that the central atom significantly influences the properties of the resulting ILs. In this study, an arsonium-based IL, trihexylmethylarsonium bis(trifluoromethylsulfonyl)amide, was synthesized. The arsonium cation was found to contribute to lower viscosity and higher ionic conductivity, while maintaining sufficient stability compared to its phosphonium counterpart. [ABSTRACT FROM AUTHOR]

Cation‐π interactions involve different metallic cations, where the bonding characteristics depend on the involved species. Here, we unravel the interaction nature features for Ga(I)‐π interactions, where different contributing terms ensure an efficient coordination of one and two Ga(I)‐atoms towards a common aromatic ring. Our results show a more balanced contribution of about ~70 % from electrostatic character and of ~30 % from orbital interaction for the prototypical GaCp, GaCp*, [Ga2Cp]+ and [Ga2Cp*]+ species. Such description strongly contrasts with the highly electrostatic character in alkali and alkaline‐earth metals counterparts. The variation from mono to inverted sandwich complexes leads to a decrease in the interaction energy from −180.9 to −148.1 kcal/mol for Cp based species, and from −184.4 to −155.5 kcal/mol in Cp* counterparts, owing to a decrease in both electrostatic and orbital stabilizing contributions. Thus, the aromatic rings exhibit coordination versatility towards one or two Ga(I) cations, retaining a sizable stabilization of the Ga(I)‐π interaction. Thus, cation‐π interactions are able to exhibit different types according to the involved metal cation, which relies on a more electrostatic/orbital balanced interaction, which serves to evaluate further mono and inverted sandwich complexes sharing a common aromatic ring. [ABSTRACT FROM AUTHOR]

Cation‐π interactions involve different metallic cations, where the bonding characteristics depend on the involved species. Here, we unravel the interaction nature features for Ga(I)‐π interactions, where different contributing terms ensure an efficient coordination of one and two Ga(I)‐atoms towards a common aromatic ring. Our results show a more balanced contribution of about ~70 % from electrostatic character and of ~30 % from orbital interaction for the prototypical GaCp, GaCp*, [Ga2Cp]+ and [Ga2Cp*]+ species. Such description strongly contrasts with the highly electrostatic character in alkali and alkaline‐earth metals counterparts. The variation from mono to inverted sandwich complexes leads to a decrease in the interaction energy from −180.9 to −148.1 kcal/mol for Cp based species, and from −184.4 to −155.5 kcal/mol in Cp* counterparts, owing to a decrease in both electrostatic and orbital stabilizing contributions. Thus, the aromatic rings exhibit coordination versatility towards one or two Ga(I) cations, retaining a sizable stabilization of the Ga(I)‐π interaction. Thus, cation‐π interactions are able to exhibit different types according to the involved metal cation, which relies on a more electrostatic/orbital balanced interaction, which serves to evaluate further mono and inverted sandwich complexes sharing a common aromatic ring. [ABSTRACT FROM AUTHOR]

The fracture toughness (KIC) of high-entropy oxides (HEOs) is critically important for several applications, but identification and quantification of the toughening mechanisms resulting from lattice-engineering/distortion in HEOs is challenging. Here, based on the classic Griffith criteria, a physics-driven theoretical equation combined with a knowledge-enabled data-driven machine-learning algorithm is proposed to predict the KIC and elucidate the toughening mechanisms of A2Zr2O7-type HEOs. Together with experimental verification, our proposed model is applied to a dataset comprising 41208 (nRE1/n)2Zr2O7 (n = 2~7) HEOs, considering the contributions of the intrinsic brittleness and increased toughness due to the local lattice distortion (LLD), thereby addressing the challenge of accurate estimating KIC in complex HEOs using the rule of mixtures. During crack tip propagation, the interaction mechanism of cations induces stress fields and charge variations of LLD and dissipates crack energy, thus, to yield the crack tip softening and the elastic shielding and to enhance the toughness of HEOs. [ABSTRACT FROM AUTHOR]

Background and Aims: Saxagliptin is an antidiabetic drug used to treat type 2 diabetes mellitus. During the manufacture of bulk and dosage forms, assay of the drugs is important in determining the percentage purity. Hence, this study aimed to develop and validate a simple, rapid, and selective method based on ultra-performance liquid chromatography-Tandem mass spectrometry (UPLC-MS/MS) analysis for the determination of saxagliptin in bulk and tablet dosage forms. Methods: Chromatographic separation was performed using a Waters Acquity UPLC BEH C18 column (2.1 X 50 mm, 1.7 μm) with a mobile phase consisting of a mixture of acetonitrile: 0.1% formic acid (60:40, v/v) at a flow rate of 0.120 mL/min. Separation was performed in 3 min run time. The analyte was ionised and detected by tandem mass spectrometry, which is performed in positive ion and multiple reaction monitoring modes. Results: Linearity was established in the 10–150 ng/mL with r²=0.9980. The results were observed to be well within the limits when validation was performed as per the ICH guidelines. Conclusion: The proposed method can be applied successfully for the analysis of saxagliptin in bulk and tablet formulations. [ABSTRACT FROM AUTHOR]

PtII complexes of π-extended dipyrrolyldiketones were synthesized as anion-responsive π-electronic molecules. The dipyrrolyldiketone PtII complexes exhibited red-shifted absorption and photoluminescence properties. In the solid state, [1 + 1]-type anion complexes formed charge-by-charge ion-pairing assemblies when combined with countercations. Detailed theoretical studies of the packing structures revealed favorable interactions between the planar anion complexes and π-electronic cations. IMPACT STATEMENT: PtII complexes of π-extended dipyrrolyldiketones, introducing arylethynyl substituents, in the form of anion complexes exhibited the formation of charge-by-charge assemblies with π-electronic cations via iπ–iπ interactions. [ABSTRACT FROM AUTHOR]

Calculations of hydration energies are extremely important in physical, chemical, and life sciences, and therefore their values need to be accurately determined if these energies were to be used to derive the proper and correct physico-chemical mechanisms. Here, we prove the existence of absolute correlation between ionization and hydration energies for transition metal cations. The said absolute correlation can be exploited in an unambiguous manner to verify the calculated hydration energies for divalent and trivalent transition metal cations. [ABSTRACT FROM AUTHOR]

The present paper explores the dynamics of ion‐acoustic solitary waves (IASWs) within an unmagnetized, highly relativistic quantum plasma containing positive and negative ions alongside electrons, employing the quantum hydrodynamic model. The treatment accounts for the inertial characteristics of negative and positive ions, considering electrons as inertialess. The nonlinear nature of quantum IASWs is investigated through the derivation of the Korteweg–de Vries equation using the reductive perturbation method. The investigation highlights how wave propagation characteristics, whether compressive or rarefactive, are substantially modulated by several parameters, such as the quantum diffraction parameter (H), relativistic effects (u0/c), equilibrium density (p), and ion mass ratio (Q). The analysis identifies the existence of both slow and fast wave modes, heavily influenced by the relativistic parameters involved. Our findings have significant implications for the understanding of both laboratory and space plasmas, especially in contexts where negative ions are present. [ABSTRACT FROM AUTHOR]