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Depletion interactions are thought to significantly contribute to the organization of intracellular structures in the crowded cytosol. The strength of depletion interactions depends on physical parameters such as the depletant number density and the depletant size ratio. Cells are known to dynamically regulate these two parameters by varying the copy number of proteins of a wide distribution of sizes. However, mammalian cells are also known to keep the total protein mass density remarkably constant, to within 0.5% throughout the cell cycle. We thus ask how the strength of depletion interactions varies when the total depletant mass is held fixed, a.k.a. fixed-mass depletion. We answer this question via scaling arguments, as well as by studying depletion effects on networks of reconstituted semiflexible actin in silico and in vitro. We examine the maximum strength of the depletion interaction potential U∗ as a function of q, the size ratio between the depletant and the matter being depleted. We uncover a scaling relation U∗ ∼ qζ for two cases: fixed volume fraction φ and fixed mass density ρ. For fixed volume fraction, we report ζ < 0. For the fixed mass density case, we report ζ > 0, which suggests that the depletion interaction strength increases as the depletant size ratio is increased. To test this prediction, we prepared our filament networks at fixed mass concentrations with varying sizes of the depletant molecule poly(ethylene glycol) (PEG). We characterize the depletion interaction strength in our simulations via the mesh size. In experiments, we observe two distinct actin network morphologies, which we call weakly bundled and strongly bundled. We identify a mass concentration where different PEG depletant sizes lead to weakly bundled or strongly bundled morphologies. For these conditions, we find that the mesh size and intra-bundle spacing between filaments across the different morphologies do not show significant differences, while the dynamic light scattering relaxation time and storage modulus between the two states do show significant differences. Our results demonstrate the ability to tune actin network morphology and mechanics by controlling depletant size and give insights into depletion interaction mechanisms under the fixed-depletant-mass constraint relevant to living cells. [ABSTRACT FROM AUTHOR]

The titular domain-based local pair natural orbital (DLPNO) approximation is the most widely used method for extending correlated wave function models to large molecular systems, yet its fidelity for intermolecular interaction energies in large supramolecular complexes has not been thoroughly vetted. Non-covalent interactions are sensitive to tails of the electron density and involve nonlocal dispersion that is discarded or approximated if the screening of pair natural orbitals (PNOs) is too aggressive. Meanwhile, the accuracy of the DLPNO approximation is known to deteriorate as molecular size increases. Here, we test the DLPNO approximation at the level of second-order Møller–Plesset perturbation theory (MP2) and coupled-cluster theory with singles, doubles, and perturbative triples [CCSD(T)] for a variety of large supramolecular complexes. DLPNO-MP2 interaction energies are within 3% of canonical values for small dimers with ≲10 heavy atoms, but for larger systems, the DLPNO approximation is often quite poor unless the results are extrapolated to the canonical limit where the threshold for discarding PNOs is taken to zero. Counterpoise correction proves to be essential in reducing errors with respect to canonical results. For a sequence of nanoscale graphene dimers up to ( C 96 H 24 ) 2 , extrapolated DLPNO-MP2 interaction energies agree with canonical values to within 1%, independent of system size, provided that the basis set does not contain diffuse functions; these cause the DLPNO approximation to behave erratically, such that results cannot be extrapolated in a meaningful way. DLPNO-CCSD(T) calculations are typically performed using looser PNO thresholds as compared to DLPNO-MP2, but this significantly impacts accuracy for large supramolecular complexes. Standard DLPNO-CCSD(T) settings afford errors of 2–6 kcal/mol for dimers involving coronene (C24H12) and circumcoronene (C54H18), even at the DLPNO-CCSD(T1) level. [ABSTRACT FROM AUTHOR]

Inspired by biological channels, achieving precise separation of ion/water and ion/ion requires finely tuned pore sizes at molecular dimensions and deliberate exposure of charged groups. Covalent organic frameworks (COFs), a class of porous crystalline materials, offer well-defined nanoscale pores and diverse structures, making them excellent candidates for nanofluidic channels that facilitate ion and water transport. In this study, we perform molecular simulations to investigate the structure and kinetics of water and ions confined within the typical COFs with varied exposure of charged groups. The COFs exhibit vertically arrayed nanochannels, enabling diffusion coefficients of water molecules within COFs to remain within the same order of magnitude as in the bulk. The motion of water molecules manifests in two distinct modes, creating a mobile hydration layer around acid groups. The ion diffusion within COFs displays a notable disparity between monovalent (M+) and divalent (M2+) cations. As a result, the selectivity of M+/M2+ can exceed 100, while differentiation among M+ is less pronounced. In addition, our simulations indicate a high rejection (R > 98%) in COFs, indicating their potential as ideal materials for desalination. The chemical flexibility of COFs indicates that would hold significant promise as candidates for advanced artificial ion channels and separation membranes. [ABSTRACT FROM AUTHOR]

This article explores the shift in chemical physics research towards studying single molecules and nanoparticles instead of bulk samples. Advancements in experimental techniques, such as single-molecule absorption and fluorescence spectroscopy, have made this shift possible. The article discusses various observations made through single-molecule spectroscopy, as well as theoretical considerations and applications in biology, materials science, and nanophotonics. It provides a summary of studies conducted using single-molecule spectroscopy in different disciplinary categories, demonstrating its interdisciplinary nature. The article concludes by discussing the challenges and future directions in the field, including integrating particle tracking with time-dependent spectroscopy and actively manipulating nanoscale objects. [Extracted from the article]

Multicomponent macromolecular mixtures often form higher-order structures, which may display non-ideal mixing and aging behaviors. In this work, we first propose a minimal model of a quaternary system that takes into account the formation of a complex via a chemical reaction involving two macromolecular species; the complex may then phase separate from the buffer and undergo a further transition into a gel-like state. We subsequently investigate how physical parameters such as molecular size, stoichiometric coefficients, equilibrium constants, and interaction parameters affect the phase behavior of the mixture and its propensity to undergo aging via gelation. In addition, we analyze the thermodynamic stability of the system and identify the spinodal regions and their overlap with gelation boundaries. The approach developed in this work can be readily generalized to study systems with an arbitrary number of components. More broadly, it provides a physically based starting point for the investigation of the kinetics of the coupled complex formation, phase separation, and gelation processes in spatially extended systems. [ABSTRACT FROM AUTHOR]

We present a simple approximation to estimate the largest charge that a given molecule can hold until fragmentation into smaller charged species becomes more energetically favorable. This approximation solely relies on the ionization potentials, electron affinities of the parent and fragment species, and also on the neutral parent's dissociation energy. By parameterizing these quantities, it is possible to obtain analytical phase diagrams of polycationic stability. We demonstrate the applicability of this approach by discussing the maximal charge dependence on the size of the molecular system. A numerical demonstration for linear polyenes, monocyclic annulenes, and helium clusters is provided. [ABSTRACT FROM AUTHOR]

Static and time-dependent quantum-mechanical approaches have been employed in the literature to characterize the physics of light-emitting molecules and nanostructures. However, the electromagnetic emission induced by an input current has remained beyond the realm of molecular simulations. This is the challenge addressed here with the help of an equation of motion for the density matrix coupled to a photon bath based on a Redfield formulation. This equation is evolved within the framework of the driven-Liouville von Neumann approach, which incorporates open boundaries by introducing an applied bias and a circulating current. The dissipated electromagnetic power can be computed in this context from the time derivative of the energy. This scheme is applied in combination with a self-consistent tight-binding Hamiltonian to investigate the effects of bias and molecular size on the electroluminescence of metallic and semiconducting chains. For the latter, a complex interplay between bias and molecular length is observed: there is an optimal number of atoms that maximizes the emitted power at high voltages but not at low ones. This unanticipated behavior can be understood in terms of the band bending produced along the semiconducting chain, a phenomenon that is captured by the self-consistency of the method. A simple analytical model is proposed that explains the main features revealed by the simulations. The methodology, applied here at a self-consistent tight-binding level but extendable to more sophisticated Hamiltonians such as density functional tight binding and time dependent density functional theory, promises to be helpful for quantifying the power and quantum efficiency of nanoscale electroluminescent devices. [ABSTRACT FROM AUTHOR]

In this work, the effects of finite size on the determination of the three-phase coexistence temperature (T3) of the carbon dioxide (CO2) hydrate have been studied by molecular dynamic simulations and using the direct coexistence technique. According to this technique, the three phases involved (hydrate–aqueous solution–liquid CO2) are placed together in the same simulation box. By varying the number of molecules of each phase, it is possible to analyze the effect of simulation size and stoichiometry on the T3 determination. In this work, we have determined the T3 value at 8 different pressures (from 100 to 6000 bar) and using 6 different simulation boxes with different numbers of molecules and sizes. In two of these configurations, the ratio of the number of water and CO2 molecules in the aqueous solution and the liquid CO2 phase is the same as in the hydrate (stoichiometric configuration). In both stoichiometric configurations, the formation of a liquid drop of CO2 in the aqueous phase is observed. This drop, which has a cylindrical geometry, increases the amount of CO2 available in the aqueous solution and can in some cases lead to the crystallization of the hydrate at temperatures above T3, overestimating the T3 value obtained from direct coexistence simulations. The simulation results obtained for the CO2 hydrate confirm the sensitivity of T3 depending on the size and composition of the system, explaining the discrepancies observed in the original work by Míguez et al. [J. Chem Phys. 142, 124505 (2015)]. Non-stoichiometric configurations with larger unit cells show a convergence of T3 values, suggesting that finite-size effects for these system sizes, regardless of drop formation, can be safely neglected. The results obtained in this work highlight that the choice of a correct initial configuration is essential to accurately estimate the three-phase coexistence temperature of hydrates by direct coexistence simulations. [ABSTRACT FROM AUTHOR]

Polymers are known to wet nanopores with high surface energy through an atomically thin precursor film followed by slower capillary filling. We present here light interference spectroscopy using a mesoporous membrane-based chip that allows us to observe the dynamics of these phenomena in situ down to the sub-nanometer scale at milli- to microsecond temporal resolution. The device consists of a mesoporous silicon film (average pore size 6 nm) with an integrated photonic crystal, which permits to simultaneously measure the phase shift of thin film interference and the resonance of the photonic crystal upon imbibition. For a styrene dimer, we find a flat fluid front without a precursor film, while the pentamer forms an expanding molecular thin film moving in front of the menisci of the capillary filling. These different behaviors are attributed to a significantly faster pore-surface diffusion compared to the imbibition dynamics for the pentamer and vice versa for the dimer. In addition, both oligomers exhibit anomalously slow imbibition dynamics, which could be explained by apparent viscosities of six and eleven times the bulk value, respectively. However, a more consistent description of the dynamics is achieved by a constriction model that emphasizes the increasing importance of local undulations in the pore radius with the molecular size and includes a sub-nanometer hydrodynamic dead, immobile zone at the pore wall but otherwise uses bulk fluid parameters. Overall, our study illustrates that interferometric, opto-fluidic experiments with mesoporous media allow for a remarkably detailed exploration of the nano-rheology of polymeric liquids. [ABSTRACT FROM AUTHOR]

Beyond well-documented confinement and surface effects arising from the large internal surface and severely confining porosity of nanoporous hosts, the transport of nanoconfined fluids remains puzzling in many aspects. With striking examples such as memory, i.e., non-viscous effects, intermittent dynamics, and surface barriers, the dynamics of fluids in nanoconfinement challenge classical formalisms (e.g., random walk, viscous/advective transport)—especially for molecular pore sizes. In this context, while molecular frameworks such as intermittent Brownian motion, free volume theory, and surface diffusion are available to describe the self-diffusion of a molecularly confined fluid, a microscopic theory for collective diffusion (i.e., permeability), which characterizes the flow induced by a thermodynamic gradient, is lacking. Here, to fill this knowledge gap, we invoke the concept of "De Gennes narrowing," which relates the wavevector-dependent collective diffusivity D0(q) to the fluid structure factor S(q). First, using molecular simulation for a simple yet representative fluid confined in a prototypical solid (zeolite), we unravel an essential coupling between the wavevector-dependent collective diffusivity and the structural ordering imposed on the fluid by the crystalline nanoporous host. Second, despite this complex interplay with marked Bragg peaks in the fluid structure, the fluid collective dynamics is shown to be accurately described through De Gennes narrowing. Moreover, in contrast to the bulk fluid, the departure from De Gennes narrowing for the confined fluid in the macroscopic limit remains small as the fluid/solid interactions in severe confinement screen collective effects and, hence, weaken the wavevector dependence of collective transport. [ABSTRACT FROM AUTHOR]

The GW electron–hole interaction kernel, which includes two second-order exchange terms in addition to the first-order direct and exchange terms considered in the conventional GW + Bethe–Salpeter method, is applied to 10 two-molecular systems and six thermally activated delayed fluorescence (TADF) molecules in which inter- and intramolecular charge transfer excitations are expected to occur. The contributions of the two second-order exchange terms are almost zero for intermolecular charge transfer excitations and ∼0.75 eV for intramolecular charge transfer excitations according to our exciton analysis method with exciton wave functions. For TADF molecules, we found that the second-order exchange terms are more significant than the first-order exchange terms, and the contributions—even for local-type and delocalized-type excitations—are not negligibly small. We revealed that the two second-order exchange terms are proportional to the molecular size, the exciton binding energy, and the electron–hole overlap strength for intramolecular charge-transfer excitations. We believe that our findings are indispensable for further considerations of the GW method in the future. [ABSTRACT FROM AUTHOR]

Given the negative fitness effects that pathogens impose on their hosts, the benefits of resistance should be universal. However, there is marked variation across plant species in the number of nucleotide-binding leucine-rich repeat receptors, which form a cornerstone of defense. The growth–defense trade-off hypothesis predicts costs associated with defense investment to generate variation in these traits. Our analysis comparing features of the intracellular immune-receptor repertoires with trait data of 187 species shows that in wild plants, the size of the molecular defense repertoire correlates negatively with growth. By contrast, we do not find evidence for a growth–defense trade-off in agricultural plants. Our cross-species approach highlights the central role of defense investment in shaping ecological trait variation and its sensitivity to domestication. [ABSTRACT FROM AUTHOR]

Glass transition is one of the most crucial physical properties for polymerical materials. As a typical complex polymerical material, the glass transition phenomenon in asphalt binder is directly related to their temperature-related properties. To investigate the glass transition characteristics, this study delves into the glass transition temperature of asphalt binder based on molecular dynamics simulations. It is found that the calculation range for the glass transition temperature sits between 100 and 400 K. The evolution of asphalt binder structure is influenced by different cooling rates, where lower cooling rates allow sufficient microstructural rearrangement, resulting in a smaller volume at the lower temperature. Model size is closely associated with the glass transition region. As the size increases, the transition region significantly expands. Increasing the model size also reduces volume fluctuations after isothermal relaxation, providing more stable volume changes. It is observed that higher cooling rates with a model size over 100 Å can well reproduce the glass transition process of asphalt binders. This work provides atomic-scale insights for the glass transition phenomenon in asphalt binder, which could be beneficial for the design of high-performance asphalt binder. [ABSTRACT FROM AUTHOR]

DNA mixture analysis poses a significant challenge in forensic genetics, particularly when dealing with degraded and trace amount DNA samples. Multi-SNPs (MNPs) are genetic markers similar to microhaplotypes but with smaller molecular sizes (< 75 bp), making them theoretically more suitable for analyzing degraded and trace amount samples. In this case report, we investigated a cold case involving a campstool stored for over a decade, aiming to detect and locate the suspect's DNA. We employed both conventional capillary electrophoresis-based short tandem repeat (CE-STR) analysis and next-generation sequencing-based multi-SNP (NGS-MNP) analysis. The typing results and deconvolution of the mixed CE-STR profiles were inconclusive regarding the presence of the suspect's DNA in the mixed samples. However, through NGS-MNP analysis and presence probability calculations, we determined that the suspect's DNA was present in the samples from Sect. 4−1 with a probability of 1-8.41 × 10− 6 (99.999159%). This evidence contradicted the suspect's statement and aided in resolving the case. Our findings demonstrate the significant potential of MNP analysis for examining degraded and trace amount DNA mixtures in forensic investigations. [ABSTRACT FROM AUTHOR]

Summary: An expanding list of marine species has been identified and evaluated for their potential bioactivity and nutritional values. Most attention is directed toward utilising protein‐rich by‐products of fish processing for their bioactive functionalities, which can aid in minimising waste and add value to underutilised resources. Milt and roe, the reproductive constituents of fish, are known to contain a high concentration of nutritional content. Bioactive peptides derived from these constituents have shown several biological activities including antihypertensive, antibacterial, anticoagulant, anti‐inflammatory, anti‐obesity, anti‐cancer, and antioxidant activities. These peptides are commonly extracted by enzymatic hydrolysis and purified by different chromatographic methods according to their mass, molecular size, and composition. This review discusses the approaches to produce, purify, and characterise the protein hydrolysates from fish milt and roe and delves into the compositions of the nutraceutical compounds derived from milt and roe. The review also highlights the bioactive properties of the milt and roe‐derived peptides that can have potential applications in the food, nutraceutical, pharmaceutical, and cosmeceutical industries. [ABSTRACT FROM AUTHOR]

Multi-layer membrane filtration is a widely used technology for separating and purifying different components of a liquid mixture. This technique involves passing the liquid mixture through a series of membranes with decreasing pore sizes, which allows for the separation of different components according to their molecular size. This study investigates the filtration process of a fluid through a two-dimensional porous medium designed for seawater desalination. The focus is on understanding the impact of various parameters such as the coefficient of friction, velocity, and the number of layers on filtration efficiency. The results reveal that the number of layers plays a crucial role in desalination, with an increase in layers leading to enhanced filtration quality, following a power law relationship. The study explores the influence of the coefficient of friction on filtration performance, emphasizing its significant effect on the number of particles filtered over time. Additionally, the role of the initial velocity in filtration efficiency is examined, showing distinct effects at both high and low velocities. Biofouling is identified as a factor influencing filtration, with an initial increase in filtered particles followed by a decline due to particle accumulation in pores. [ABSTRACT FROM AUTHOR]

Cationic starch (CatS) coating of cellulose fabrics enables salt‐free reactive dyeing. However, the relation of the degree of substitution and CatS concentration in the dyeing procedure are open issues. Accordingly, three cationic starches of increasing degree of substitution were used at different concentrations for the coating of cotton fabrics. Fabrics were evaluated for stiffness, dye uptake, dye exhaustion, wash fastness and nitrogen content. With an increasing degree of substitution coating solutions become more viscous, resulting in increased wet pick‐up and less stiff coated fabrics. These fabrics show increasing dye absorption and color generation. Due to the molecular size of the cationic starch, yarn/fiber ring dyeing is supposed present. Specifically, color generation can be adjusted by initial cationic starch coating concentration. Above 5 % CatS concentration ceases to have an increasing coloration effect. Pre‐treating a cellulose fabric with approximately 2.2 % CatS (Ds=0.7) enables similar coloration to a standard reactive dyeing protocol. Light fastness is reduced by 1–1.5 compared to salt‐based reactive dyeing. Rub fastness decreases by 1–2 only for higher substituted cationic starches (Ds=0.7). Nitrogen analysis reveals that a share of the CatS elutes off the fabrics into the dye bath. [ABSTRACT FROM AUTHOR]

The current state of reticular chemistry enables the synthesis of a wide range of highly porous nanomaterials for gas separation, including metal‐organic frameworks (MOFs), covalent organic frameworks (COFs), porous organic cages (POCs), metal‐organic cages (MOCs), and polyhedra (MOPs). This perspective focuses on membrane technology, a key player in energy‐efficient gas separations. It explores the world of reticular materials, taking a glance at tiny pore windows with narrow openings, which are ideal for high‐resolution molecular sieving, and how to design them. Promising concepts in this field are membranes consisting of neat materials, but also mixed matrix membranes, where polymeric films incorporate reticular fillers, creating cost‐efficient membranes. This article sheds light on the potential use of reticular materials as membrane components. The reticular synthesis of MOFs offers the ability to separate gas molecules with minimal size differences effectively. For COFs, the crucial factor lies in reducing their pore size, preferably through functional group modifications. Porous cage compounds can achieve fine distribution from homogeneous dispersions into polymers making them excellent candidates for mixed matrix membranes. This perspective provides strategies and guiding principles for the future of reticular nanomaterials‐based membranes, addressing the pressing need for advanced and efficient separation technologies. [ABSTRACT FROM AUTHOR]

Graphene‐like molecules with multiple zigzag edges are emerging as promising gain materials for organic lasers. Their emission wavelengths can vary widely, ranging from visible to near‐infrared (NIR), as the molecular size increases. Specifically, rhombus‐shaped molecular graphenes with two pairs of parallel zigzag edges, known as [n]rhombenes, are excellent candidates for NIR lasers due to their small energy gaps. However, synthesizing large‐size rhombenes with emission beyond 800 nm in solution remains a significant challenge. In this study, we present a straightforward synthesis of an aryl‐substituted [4]rhombene derivative, [4]RB‐Ar, using a method that combines intramolecular radical‐radical coupling with Bi(OTf)3‐mediated cyclization of vinyl ethers. The structure of [4]RB‐Ar was confirmed through X‐ray crystallographic analysis. Bond length analysis and theoretical calculations indicate that aromatic sextets are predominantly localized along the molecule's long axis. Significantly, [4]RB‐Ar demonstrates narrow amplified spontaneous emission at around 834 nm when dispersed in polystyrene thin films. Moreover, solution‐processed distributed feedback lasers employing [4]RB‐Ar as the active gain material display tunable narrow emissions in the range of 830 to 844 nm. [ABSTRACT FROM AUTHOR]

Background: The sect. Chrysantha Chang of plants with yellow flowers of Camellia species as the "Queen of the Tea Family", most of these species are narrowly distributed endemics of China and are currently listed Grde-II in National Key Protected Wild Plant of China. They are commercially important plants with horticultural medicinal and scientific research value. However, the study of the sect. Chrysantha species genetics are still in its infancy, to date, the mitochondrial genome in sect. Chrysantha has been still unexplored. Results: In this study, we provide a comprehensive assembly and annotation of the mitochondrial genomes for four species within the sect. Chrysantha. The results showed that the mitochondrial genomes were composed of closed-loop DNA molecules with sizes ranging from 850,836 bp (C. nitidissima) to 1,098,121 bp (C. tianeensis) with GC content of 45.71–45.78% and contained 48–58 genes, including 28–37 protein-coding genes, 17–20 tRNA genes and 2 rRNA genes. We also examined codon usage, sequence repeats, RNA editing and selective pressure in the four species. Then, we performed a comprehensive comparison of their basic structures, GC contents, codon preferences, repetitive sequences, RNA editing sites, Ka/Ks ratios, haplotypes, and RNA editing sites. The results showed that these plants differ little in gene type and number. C. nitidissima has the greatest variety of genes, while C. tianeensis has the greatest loss of genes. The Ka/Ks values of the atp6 gene in all four plants were greater than 1, indicating positive selection. And the codons ending in A and T were highly used. In addition, the RNA editing sites differed greatly in number, type, location, and efficiency. Twelve, six, five, and twelve horizontal gene transfer (HGT) fragments were found in C. tianeensis, Camellia huana, Camellia liberofilamenta, and C. nitidissima, respectively. The phylogenetic tree clusters the four species of sect. Chrysantha plants into one group, and C. huana and C. liberofilamenta have closer affinities. Conclusions: In this study, the mitochondrial genomes of four sect. Chrysantha plants were assembled and annotated, and these results contribute to the development of new genetic markers, DNA barcode databases, genetic improvement and breeding, and provide important references for scientific research, population genetics, and kinship identification of sect. Chrysantha plants. [ABSTRACT FROM AUTHOR]

Refractory organic matter (RfOM) is ubiquitous in aquatic environment and plays various roles in regulating the fate, transport, toxicity, and bioavailability of chemical species, such as metals, emerging organic contaminants, and nanomaterials. RfOM is mainly represented by humic acids (HA) as the acid insoluble fraction of organic matrix. Considering the complex and multicomponent characteristic of HA, a detailed study was designed to elucidate the fate of molecular size fractions (MSFrs) of humic under solar irradiation in the presence of polyaniline (PANI)-modified TiO2 composites. Humic acid as a consortium of diverse molecular size fractions with different tendencies towards oxidation requires further assessment by UV–vis and fluorescence spectroscopic parameters complementary to previous studies on the photocatalytic degradation of RfOM by using TiO2 and PANI-TiO2 composites. Absorbance-based removal efficiencies under initial and post-photocatalytic conditions showed a re-formation trend during photocatalysis in the presence of PANI and TiO2 where higher MSFrs were transformed to lower MSFrs that was apparent for < 3 kDa fraction. Completely different profiles were observed for PT-41 and PT-81 indicating similar degradation pathways independent of PANI ratio in the composite. As confirmed by the investigated parameters, formation of both 450 kDa and 220 kDa MSFrs were evident under all conditions indicating in situ generation of higher MSFrs. The eligibility of coupled absorbance-fluorescence measurements to discern molecular size distribution of humic acid via oxidative degradation was also investigated. Excitation-emission matrix (EEM) contour plots emphasized the ratio dependency of PANI modification of TiO2 and revealed sample specific variations that were more pronounced in terms of the emergence of tyrosine- and tryptophan-like aromatic proteins. [ABSTRACT FROM AUTHOR]

Fracturing operations can effectively improve the production of low-permeable reservoirs. The performance of fracturing fluids directly affects the fracturing efficiency and back flow capacity. As polymerbased fracturing fluids (such as guar gum (GG), polyacrylamide (HPAM), etc.) are high-viscosity fluids formed by viscosifiers and crosslinking agents, the degree of gel breakage after the fracturing operation directly influences the damage degree to the reservoir matrix and the mobility of oil angd gas produced from the reservoir into the wellbore. This study compared the viscosity, molecular weight, and particle size of the fracturing fluid after gel breakage prepared by GG and HPAM as viscosifiers, as well as evaluate their damage to the core. Results show that the viscosities of the gel-breaking fluid increased with the concentration of the viscosifier for both the HPAM-based and GG-based fracturing fluids. For the breaking fluid with the same viscosity, the molecular weight in the HPAM-based gel-breaking fluid was much larger than that in the GG-based system. Moreover, for the gel-breaking fluid with the same viscosity, the molecular particle size of the residual polymers in the HPAM-based system was smaller than that in the GG-based system. The damage to the core with the permeability of 1 × 10-3 μm² caused by both the HPAM-based and GG-based gel-breaking fluids decreased with the increase in the solution viscosity. For the gel-breaking fluid systems with the same viscosity (i.e., 2-4 mPa s), the damage of HPAM-based fracturing fluid to low-permeability cores was greater than the GG-based fracturing fluid (45.6%e80.2%) since it had a smaller molecular particle size, ranging from 66.2% to 77.0%. This paper proposed that the damage caused by hydraulic fracturing in rock cores was related to the partilce size of residual polymers in gel-breaking solution, rather than its molecular weight. It was helpful for screening and optimizing viscosifiers used in hydraulic fracturing process. [ABSTRACT FROM AUTHOR]

To clarify the adsorption behavior of fluorocarbon surfactants on PMMA surfaces, the contact angles of two nonionic fluorocarbon surfactants (FNS-1 and FNS-2) and an anionic fluorocarbon surfactant (FAS) on polymethylmethacrylate (PMMA) surface were determined using the sessile drop method. Moreover, the effects of molecular structures on the surface tension, adhesion tension, solid–liquid interfacial tension, and adhesion work of the three fluorocarbon surfactants were investigated. The results demonstrate that the adsorption amounts for three fluorocarbon surfactants at the air–water interface are 4~5 times higher than those at the PMMA–solution interface. The three fluorocarbon surfactants adsorb on the PMMA surface by polar groups before CMC and by hydrophobic chains after CMC. Before CMC, FNS-2 with the smallest molecular size owns the highest adsorption amount, while FAS with large-branched chains and electrostatic repulsion has the smallest adsorption amount. After CMC, the three fluorocarbon surfactants form aggregates at the PMMA-liquid interface. FAS possesses the smallest adsorption amount after CMC. Besides, FNS-1 possesses a higher adsorption amount than FNS-2 due to the longer fluorocarbon chain and the lower CMC value of FNS-1. The adsorption behaviors of nonionic and anionic fluorocarbon surfactants on the PMMA surface are different. FAS forms interfacial aggregates before CMC, which may be attributed to the electrostatic interaction between the anionic head of FAS and the PMMA surface. [ABSTRACT FROM AUTHOR]

This study evaluated non-fibrous Mg-clays as potential adsorbents of emerging contaminants (ECs) from water. The materials were characterized, and their textural and structural properties were related to their ability to remove two model EC molecules: ciprofloxacin (CPX) and lidocaine (LID). The results showed that Ad-6 and Ad-7 are mixed-layer kerolite/stevensite, while Ad-5 and Ad-8 are mainly composed of smectite minerals like stevensite and saponite, respectively. Ad-8 exhibited the highest CPX-adsorption capacity (0.91 mmol·g−1 clay), likely due to its saponite content. Mixed-layer materials also performed well, with Ad-6 and Ad-7 achieving an adsorption capacity of 0.8 and 0.55 mmol·g−1 clay, respectively. Adsorption studies suggested that CPX is adsorbed through ion exchange in materials with high smectite content (Ad-8 and Ad-5), while interstratified materials showed enhanced retention due to kerolite presence, which improves their porous structures. Similar findings were observed for LID, indicating a cationic-exchange mechanism for LID adsorption in all the materials and suggesting that the molecular size of the EC could regulate the removal capacity of these materials. This work showed that the studied Mg-clays could be effectively used for the removal of pharmaceutical pollutants, expanding their commercial possibilities. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the effect of molecular size on the pulmonary pharmacokinetics (PK) of proteins following systemic and local administration in wild-type mice. Methods: A non-cross-reactive antibody trastuzumab, and F(ab′)2, Fab, and scFv fragments of this antibody were used for the investigation. Proteins were injected intravenously or via intratracheal instillation, and PK was measured in plasma, lungs, trachea, bronchi, and bronchoalveolar lavage (BAL) using ELISA. Concentrations in BAL were urea normalized. Results: Following systemic administration, the biodistribution coefficient (BC) for lungs, trachea, bronchi, and BAL was 11%, 11%, 15%, and 2% for the antibody; 15%, 7%, 13%, and 8% for F(ab′)2; 25%, 17%, 28%, and 46% for Fab; and 14%, 1%, 2%, and 50% for scFv. The antibody exposure in BAL was ~50-fold lower than plasma and ~5–7-fold lower than lung tissues. A tissue-dependent BC vs. molecular size relationship was observed, where distribution in tissues was the highest for Fab (50 kDa), and scFv demonstrated the highest distribution in the BAL. PK data generated following local administration were quite variable; however, local dosing resulted in BAL exposures that were 10–100-fold higher than those achieved after systemic dosing for all proteins. The BAL antibody concentrations were 100–1000-fold higher than plasma concentrations initially, which normalized by day 14. For most proteins, local dosing resulted in higher lung concentrations than trachea and bronchi, opposite to what was observed after systemic dosing. Conclusions: The PK data presented here provide an unprecedented quantitative insight into the effect of molecular size on the pulmonary disposition of proteins following systemic and local administration. [ABSTRACT FROM AUTHOR]

The acrylation degree of vegetable oils plays a relevant role in determining the mechanical properties of the resulting polymers. Both epoxide and acrylate functionalities participate in polymerization reactions, producing various types of chemical bonds in the polymer network, which contribute to specific properties such as molecular size distribution, crosslinking degree, and glass transition temperature (Tg). The accurate identification of epoxide and acrylated groups in triglyceride molecules helps to predict their behavior during the polymerization process. A methodology based on analytical spectrometric techniques, such as direct infusion, mass spectrometry with electrospray ionization, and ultra-high-performance liquid chromatography, is used in combination with FTIR and 1H NMR to characterize the epoxy and acrylic functionalities in the fatty chains with different numbers of carbon atoms of partially acrylated triglycerides obtained by a non-catalytic reaction. [ABSTRACT FROM AUTHOR]

Cosmetically applicable soluble agonists for Toll-like receptor 2 (TLR2), which can strengthen skin barrier function, were produced by fermentation of asparagus (Asparagus officinalis L.) extract supplemented with skimmed milk using Lactobacillus delbrueckii subsp. lactis TL24. Their molecular size was estimated to be >100 kDa. Their TLR2-stimulating activity was stable over 1 year at 4 °C, but it decreased by more than 95% within 10 and 4 months at 25 °C and 40 °C, respectively. The possibility of stabilization of TLR2-stimulating activity by powdering was tested, and we found that lyophilization with 10% or a higher amount of dextrin could stabilize the activity even at 40 °C. The powdered fermented product dose-dependently stimulated TLR2. It augmented the formation of tight junctions in normal human keratinocytes, as detected by fluorescence staining of occludin and ZO-1, whereas their protein and gene expression levels did not increase, suggesting that a change in subcellular localization of these proteins without significant changes in their amounts might be responsible. The powder nature has some benefits over the aqueous, besides stability, e.g., it can be dissolved just before application, allowing fresh material to be used each time, and it may widen a range of cosmetic applications in non-aqueous types of cosmetics. [ABSTRACT FROM AUTHOR]

Protein therapeutics are emerging as essential technologies due to their functional and chemical properties. However, their application is currently limited to delivery by oral and injection methods—the former being inefficient and the latter invasive and potentially tissue damaging. Researchers are, therefore, exploring noninvasive delivery systems for proteins through the skin, including transdermal and topical delivery. The large molecular size of proteins presents a key challenge for skin penetration, hindering their ability to penetrate the dense skin lamellar structure. This review focuses on using nanoparticles as carriers to increase protein stability and enhance skin penetration. The use of noninvasive or minimally invasive enhancers for controlling and improving penetration depth is also examined. Furthermore, the physical properties of nanoparticles that affect delivery are evaluated, aiming to propose ways to advance transdermal and topical delivery methods in the future. [ABSTRACT FROM AUTHOR]

Most albumin in blood plasma is thought to be monomeric with some 5% covalently dimerized. However, many reports in the recent biophysics literature find that albumin is reversibly dimerized or even oligomerized. We review data on this from X‐ray crystallography and diverse biophysical techniques. The number‐average molecular weight of albumin would be increased by dimerization, affecting size‐dependent filtration processes of albumin such as at the glycocalyx of the capillary endothelium and the podocyte slit‐diaphragm of the renal glomerulus. If correct, and depending on characteristics of the process, such as Kd, reversible dimerization of albumin in plasma would have major implications for normal physiology and medicine. We present quantitative models of the impact of dimerization on albumin molecular forms, on the number‐average molecular weight of albumin, and estimate the effect on the colloid osmotic pressure of albumin. Dimerization reduces colloid osmotic pressure as total albumin concentration increases below that expected in the absence of dimerization. Current models of albumin filtration by the renal glomerulus would need revision to account for the dynamic size of albumin molecules filtered. More robust biophysical data are needed to give a definitive answer to the questions posed and we suggest possible approaches to this. What is the central question of this study?Is there reversible dimerization of albumin in blood plasma? Albumin in blood plasma is generally considered monomeric apart from a small proportion of covalent dimer, but recent reports suggest it may actually be reversibly dimerized: is this physiologically significant?What is the main finding and its importance?There is some evidence that fatty acid‐free albumin dimerizes but less for native albumin. Dimerization, if proven, requires revision of the current molecular concepts underlying observed colloid osmotic pressures of plasma and renal ultrafiltration of albumin. Biophysical evidence for dimerization in plasma is currently weak. [ABSTRACT FROM AUTHOR]

The thiophene-based compounds (such as 4,6-dimethyldibenzothiophene (4,6-DMDBT)) were removed with difficultly that since relatively larger molecules sizes with evident steric hindrance and worse accessibility of active sites during hydrodesulfurization (HDS) reactions. In this study, bimodal pore structure catalysts with higher specific surface areas, larger pore volume and mesoporous diameter were prepared. Moreover, less hydroxyl group in bimodal pore supports cause weaker metal-support interaction (MSI), which further contributes to the formation of Type-II active phase that possesses more active sites. The catalyst activity results of 4,6-DMDBT reveal that the bimodal pore catalyst with a narrow-distributed distribution of mesoporous size (NiMoS/S1) exhibited the highest apparent HDS activity and intrinsic activity for 4,6-dimethyldibenzothiophene. This work can deepen our understanding of the design of catalytic bimodal catalysts with high intrinsic activity and better accessibility of active sites. [ABSTRACT FROM AUTHOR]

The objective of this study was to explore the influence of different factors on the aggregation effect on hemoglobin (Hb) and enzymes during the preparation of Polyhemoglobin-Superoxide dismutase-Catalase-Carbonic anhydrase (PolyHb-SOD-CAT-CA). Several factors including temperatures, pH values, Glutaraldehyde (GDA) amounts and enzymes amounts were investigated systematically to study their effects on the enzymes recoveries and polymerization rates including the Superoxide dismutase (SOD), Catalase (CAT) and Carbonic anhydrase (CA), as well as their effects on the molecular weight distribution of PolyHb-SOD-CAT-CA. Then the oxygen affinity and methemoglobin (MetHb) contents of obtained PolyHb-SOD-CAT-CA were measured to evaluate the effects of enzyme crosslinking on the properties of Polyhemoglobin (PolyHb) moieties in the molecular structure of obtained PolyHb-SOD-CAT-CA conjugate. The results showed that the enzyme recoveries and polymerization rates could be decreased with the temperatures increasing and could be generally kept stable in the physiological pH conditions, but presented only slight changes among the investigated enzyme amounts ranges. Although the GDA concentration increasing could promote the enzyme polymerization rates, the enzyme recoveries decreased in whole. The polymerization rate and molecular size of PolyHb-SOD-CAT-CA conjugate increased with the elevation of temperature and the concentration of GDA. Lastly, the P50 values, Hill coefficients, and MetHb contents of PolyHb-SOD-CAT-CA conjugate with different enzyme crosslinking degrees exhibited no obvious differences with each other. In conclusion, the polymerization reactions between enzymes and Hb molecules could be remarkably affected by temperatures, pH values, and GDA amounts, and the enzyme crosslinking presented no obvious effects on the Hb properties, especially about the oxygen affinity and oxidation degrees. [ABSTRACT FROM AUTHOR]

Multivalency is a fundamental principle in nature that leads to high‐affinity intermolecular recognition through multiple cooperative interactions that overcome the weak binding of individual constituents. For example, multivalency plays a critical role in lectin‐carbohydrate interactions that participate in many essential biological processes. Designing high‐affinity multivalent glycoconjugates that engage lectins results in systems with the potential to disrupt these biological processes, offering promising applications in therapeutic design and bioengineering. Here, a versatile and tunable synthetic platform for the synthesis of metallosupramolecular glycoassemblies is presented that leverages subcomponent self‐assembly, which employs metal ion templates to generate complex supramolecular architectures from simple precursors in one pot. Through ligand design, this approach provides precise control over molecular parameters such as size, shape, flexibility, valency, and charge, which afforded a diverse family of well‐defined hybrid glyconanoassemblies. Evaluation of these complexes as multivalent binders to Concanavalin A (Con A) by isothermal titration calorimetry (ITC) demonstrates the optimal saccharide tether length and the effect of electrostatics on protein affinity, revealing insights into the impact of synthetic design on molecular recognition. The presented studies offer an enhanced understanding of structure‐function relationships governing lectin‐saccharide interactions at the molecular level and guide a systematic approach towards optimizing glyconanoassembly binding parameters. [ABSTRACT FROM AUTHOR]

The importance of chitosan (CH) has grown significantly over the last two decades due to its renewable and biodegradable source, and also because of the recent increase in the our knowledge of its functionality in technological and biomedical applications. The present article reviews the biopolymer CH and its derivatives, as versatile biomaterials for potential drug delivery systems, as well as tissue engineering applications, analgesia and treatment of arthritis. CH and its derivatives, as natural antimicrobial agents, can be applied in biomedical, biotechnological, and pharmaceutical applications. Its antimicrobial activity depends on many factors such as its molecular size, source, associated components, concentration, and type of microorganism. In our research described here we prepared and characterized the dynamic viscosity and the rheological properties of a biopolymer material based on CH in solution in acidic water. The dynamic viscosity and shear stress were measured under the influence of an increasing CH concentration of 1–10 g/l and an increasing temperature of 288.15–318.15 K. [ABSTRACT FROM AUTHOR]

The crosslink interaction and rheological properties of transglutaminase (TGas) on the soy protein isolate (SPI) and the effect on patty application were studied. The TGas concentration as 0, 1, 3, 5, or 10% without incubation, or incubation at 50 °C for 1 or 4 h were measured. The molecular size of the SPI tended to increase with TGas. However, there were no differences in the SDS-PAGE results between adding 5 or 10% TGas. The rheological properties of the SPI and TGas interaction showed shear-thinning behavior with n values less than 1. The increase of TGas concentration and incubation time increased the solid-like properties according to the storage modulus increased and tanδ decreased, especially for 5% TGas with 1 or 4 h incubation time. The plant-based patties composed of TGas at 0, 1, 3, or 5% and incubated at 25 °C/1 h, 25 °C/2 h, or 4 °C/24 h were investigated. The color changed with increasing TGas concentration and incubation time. The samples hardness tended to increase with higher TGas concentrations. Cohesiveness and springiness increased when incubated at 25 °C for 2 h, especially using 5% TGas. The rheological properties and the textural properties would be highly correlated with the concentration of TGas. The structural characteristics using confocal laser scanning microscopy showed the clustering of green colors representing protein components with 3 and 5% TGas addition that might have been due to the noticeable aggregation of the protein. Thus, the crosslinking between SPI and TGas affected rheological properties, texture and structure of the plant-based patties. [ABSTRACT FROM AUTHOR]

Background: Patients with HER2-positive breast cancer can significantly benefit from HER2-directed therapy – such as the monoclonal antibody trastuzumab. However, some patients can develop therapy resistance or change HER2 status. Thus, we urgently need new, noninvasive strategies to monitor patients frequently. Extracellular vesicles (EVs) secreted from tumor cells are emerging as potential biomarker candidates. These membrane-delimited nanoparticles harbor molecular signatures of their origin cells; report rapidly on changes to cellular status; and can be frequently sampled from accessible biofluids. Results: Using Single Extracellular VEsicle Nanoscopy (SEVEN) platform that combines affinity isolation of EVs with super-resolution microscopy, here we provide multiparametric characterization of EVs with ~ 8 nm precision and molecular sensitivity. We first interrogated cell culture EVs affinity-enriched in tetraspanins CD9, CD63, and CD81; these transmembrane proteins are commonly found on EV membranes. SEVEN robustly provided critical parameters of individual, tetraspanin-enriched EVs: concentration, size, shape, molecular cargo content, and heterogeneity. Trastuzumab-resistant cells (vs. trastuzumab-sensitive) secreted more EVs. Additionally, EVs from trastuzumab-resistant cells had lower tetraspanin density and higher HER2 density. We also evaluated EVs affinity-enriched in HER2; we found that these EVs (vs. tetraspanin-enriched) were larger and more elongated. We further optimized analytical sample processing to assess a rare population of HER2-enriched EVs from patient plasma. In breast cancer patients with elevated HER2 protein expression (vs. controls), HER2-enriched EVs had distinct characteristics including typically increased number of tetraspanin molecules and larger size. Importantly, these EVs were on average 25-fold more abundant compared to no cancer controls. Conclusions: SEVEN revealed unique characteristics of HER2-enriched EVs in cultured cells and complex biological fluid. In combination with current clinical approaches, this method is well poised to support precise therapeutic decisions. [ABSTRACT FROM AUTHOR]

Robust high‐valence metal–organic framework (MOF) membranes for CO2 separations show great promise for achieving carbon neutrality. Herein, the elegant fabrication of tetravalent zirconium Materials of Institute Lavoisier‐140A (MIL‐140A) membranes are pioneered and validated the intriguing dual role for both CO2‐selective and CO2‐rejective separations by combining structural regulation with the exploitation of the appropriate anisotropic ultramicropores. This inimitable separation ability of "hitting two targets with one arrow" with distinctive molecular size cut‐offs, which originated from the significant orientation transformation, enables the membranes to satisfy multiscenario CO2 capture requirements. The preferred (h0h)‐oriented MIL‐140A membranes exhibit superior mixed CO2/CH4 separation capacities (a separation factor of ≈30), while the highly (200)‐oriented MIL‐140A membranes exhibit remarkable mixed H2/CO2 separation capacities (a separation factor of ≈540), and they both ranked at the top among the present MOF membranes. This work highlights the promising prospects of the fresh MIL‐140 series for a given membrane‐based multiscenario CO2 separation application through microstructure customization and manipulation. [ABSTRACT FROM AUTHOR]

Layer‐stacking behaviors are crucial for two‐dimensional covalent organic frameworks (2D COFs) to define their pore structure, physicochemical properties, and functional output. So far, fine control over the stacking mode without complex procedures remains a grand challenge. Herein, we proposed a "key‐cylinder lock mimic" strategy to synthesize 2D COFs with a tunable layer‐stacking mode by taking advantage of ionic liquids (ILs). The staggered (AB) stacking (unlocked) COFs were exclusively obtained by incorporating ILs of symmetric polarity and matching molecular size; otherwise, commonly reported eclipsed (AA) stacking (locked) COFs were observed instead. Mechanistic study revealed that AB stacking was induced by a confined interlocking effect (CIE) brought by anions and bulky cations of the ILs inside pores ("key" and "cylinder", respectively). Excitingly, this strategy can speed up production rate of crystalline powders (e.g. COF‐TAPT‐Tf@BmimTf2N in merely 30 minutes) under mild reaction conditions. This work highlights the enabling role of ILs to tailor the layer stacking of 2D COFs and promotes further exploration of their stacking mode‐dependant applications. [ABSTRACT FROM AUTHOR]

This study presents an innovative approach utilising molecular dynamics simulations to elucidate the polymerisation and neck formation mechanisms of phenolic resin during laser powder bed fusion (L-PBF). By developing system and dual-particle models and employing infrared thermal imaging, we established a heat source model for phenolic resin under varying parameters. Our molecular dynamics simulations, using the ReaxFF reactive force field, indicate that high-power lasers significantly enhance cross-linking, achieving a peak polymerisation degree of 78.9% at 30W and 35W power levels. Conversely, increased scanning speed slows product degradation, reducing the polymerisation degree. The interplay of laser power and scanning speed influences polymerisation, with total input energy and heating rate impacting polymerisation and molecular size. Additionally, we investigated neck formation, revealing that small vortices evolve into larger ones during sintering, promoting neck formation. Optical microscopy confirmed diverse neck shapes under different conditions. Quantitative data showed that at a scanning speed of 1000 mm/s, the polymerisation degree reached 93%, with only 2 molecules remaining post-simulation. At 30W power, the largest individual molecule observed was C849H703O117. This research offers crucial insights for selective laser sintering processes, emphasising the importance of high energy input and optimal heating rates for well-formed necks. [ABSTRACT FROM AUTHOR]

The anionic nature of both cellulose fibres and reactive dyes prevents substantial exhaustion of dye from the dyebath, which is at neutral pH before alkali is added to initiate dye fixation. Conventionally, salt is added to minimize the electrostatic repulsions that interfere with dye sorption, but that increases salt loads in effluents. An alternative is to affix cationic agents on the cellulose to overcome the inherent anionic charge, but that has generally been observed to result in uneven dye sorption. The focus of investigations in this work is to examine the influence of the ratio of charges on cellulose (of affixed cationic charges to inherent anionic charges) on the extents and evenness of dye sorption. The cationisation agent 3-chloro-2-hydroxypropyl-N,N,N-trimethylammonium chloride (CHPTAC) was grafted on loose viscose fibres to yield 12 to 185 mmol kg−1 cationic group content on the fibre that exhibited an inherent carboxyl group content of 68 mmol kg−1. Three different dyes (of varying molecular sizes and anionic group content) were employed for examination of sorption profiles. The results from both zeta potential measurements and dye sorption profiles showed evidence of limited dye uptake until the cationic group content in fibres exceeded that of the inherent carboxyl groups. Thereafter, an uptick in dye sorption was observed, with dye sorption levels increasing with rise in degree of cationisation. There were differences between the dyes in their degrees of sorption, which appear correlated with their molecular sizes. [ABSTRACT FROM AUTHOR]

2D Dion–Jacobson (DJ) perovskites show structural stability and tunability and are regarded as promising photovoltaic materials. The spacer cations play an important impact on exciton separation and charge transport of 2D perovskites. Herein, a novel spacer with thiazole as core, 2‐thiazolemethanammonium (AMT), owning characters of small molecular size, delocalized π‐electrons, and strong electron‐withdrawing ability, is introduced to construct 2D DJ perovskites. Owing to the strong orbital coupling between AMT spacer and inorganic layers, the AMT‐based perovskite exhibits type II quantum well structure, which is favorable for exciton separation. On contrary, such interaction does not appear in the DJ perovskite when aliphatic propyldiammonium (PDA), with a similar length, is used as spacer. The AMT spacer can also induce better crystallinity, resulting in reduced defect density and improved charge transport ability. The optimized device based on (AMT)MA3Pb4I13 exhibits a power conversion efficiency (PCE) of 19.69%, which is a record for 2D DJ perovskite solar cells (PSCs) (n ≤ 4). This work provides deep understanding of the impact of aromatic spacer on the electronic structure of 2D DJ perovskites and the corresponding photovoltaic performance and provides a new opportunity toward highly efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

The grain size of rice (Oryza sativa) plays a pivotal role in determining yield. It is crucial to explore the genes related to grain size and analyze their molecular mechanisms to enhance rice yield further. This study identified a small‐grain mutant small grain 12 (sg12), from the ethyl methanesulfonate‐induced mutant library of Shuhui 498, a backbone parent of heavy‐panicle hybrid rice. We found that sg12 rice mutant exhibits a decrease in grain size and 1000‐grain weight, but an increase in grain number per panicle. Genetic analysis indicated that the small grain of sg12 is controlled by a pair of semi‐dominant genes. Furthermore, cytological analysis showed that the number of longitudinal cells in the spikelet hull of sg12 decreased, indicating that SG12 regulates grain size by affecting cell proliferation. In this study, we also identified a candidate gene of SG12 as OsPPKL3, which encodes a putative protein phosphatase with Kelch‐like repeat domains. A single‐nucleotide polymorphism substitution (G/A) occurred in the conserved Kelch domain of OsPPKL3 in the sg12, resulting in the mutation of the 176th amino acid from Ala to Thr, and this amino acid substitution led to significant differences in the three‐dimensional structure of the OsPPKL3 protein. Finally, genetic analysis indicated that OsPPKL3 regulates grain size independent of Oryza sativa BRI1‐associated receptor kinase 1 (OsBAK1) and Oryza sativa Brassinosteroid‐signaling kinase 2 (OsBSK2). Overall, this study identified a new allelic mutant of OsPPKL3, clarified the cytological basis of OsPPKL3 regulating grain size, and emphasized the crucial role of the 176th amino acid in the Kelch domain of OsPPKL3 for its biological function. Our results provided important resources for further studying the molecular mechanisms of OsPPKL3 regulating grain size in rice. [ABSTRACT FROM AUTHOR]

The efficient purification of cyclohexane is critical, serving as an essential feedstock to produce resins, nylon fibers and pharmaceutical intermediates. However, efficient purification remains a challenging task due to the similarity of cyclohexane and benzene molecules in terms of size and boiling point. In this work, we reported on the synergy of pore size and silanols inside an -SVR-type zeolite for the efficient production of ultrapure cyclohexane (benzene <1 ppm) from benzene/cyclohexane mixture. Under ambient conditions, the SSZ-74 zeolite demonstrated the highest mass-based productivity of 14.5 L/kg for ultrapure cyclohexane among several common zeolites with a considerable dynamic selectivity of ~9.5. The separation ability was evaluated through density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations. The unique ordered silanols inside the zeolite frameworks demonstrated strong but reversible interactions with benzene through SiOH...π interactions, as revealed by in situ Fourier Transform infrared (FTIR) spectra. Purification of cyclohexane serves as a feedstock to produce resins, nylon fibers and pharmaceutical intermediates. Here authors combine specific pore sizes with silanols within a zeolite framework to improve the separation of cyclohexane from benzene, addressing the challenge of their molecular size similarity. [ABSTRACT FROM AUTHOR]

Despite the ongoing breakthroughs in power conversion efficiency (PCE) of perovskite solar cells (PSCs), the presence of inherent defects in perovskite films remains the predominant hurdle impeding the further progress of this promising photovoltaic technology. Herein, we propose a straightforward yet highly effective additive strategy to passivate the bulk defects of perovskite films. Specifically, based on the two-step deposition method, a functional polymer poly(2-ethyl-2-oxazoline) (PEOXA) was introduced into the PbI2 precursor solution, facilitating the formation of the PbI2-dimethyl sulfoxide phase. This solvate facilitates subsequent intercalation reactions with organic cations, resulting in the formation of high-quality perovskite films. Additionally, due to its abundant active sites and larger molecular size, PEOXA forms a three-dimensional network structure at the perovskite grain boundaries, effectively connecting the grains and suppressing ion migration. The C = O groups in PEOXA passivate the uncoordinated Pb2+ defects at the grain boundaries, inhibiting non-radiative charge recombination in the bulk. As a result, the device PCE increased from 22.02% to 24.27%. Furthermore, the PEOXA-based PSCs exhibited excellent operational stability, retaining 86% of the initial efficiency after continuous operation for 1500 h. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION Natural emulsifiers are increasingly preferred by the food industry to meet consumers' demand for ‘clean‐label’ emulsion products. In the present study, 10 short‐term retrograded starches with unique molecular structures were explored to examine the relationships between starch structures and their ability to form stable oil‐in‐water emulsions.Waxy maize starch showed the largest value of contact angle and conductivity of emulsion, whereas potato and lentil starch showed the lowest value of contact angle and conductivity of emulsion, respectively. Emulsion prepared by rice starch showed the lowest, whereas that of sweet potato starch showed the highest value of viscosity. Consequentially, the emulsion stabilized with waxy maize and tapioca starch showed the smallest and less polydisperse droplets, resulting in a much higher emulsifying index. On the other hand, emulsion prepared with potato starch showed the highest stability compared to other starches. Correlation analysis suggested that starches with larger molecular size, a lower amylose content and shorter amylopectin short chains had a higher emulsification ability, whereas the amount of starch molecular interactions formed during short‐term retrogradation revealed no obvious linking to emulsion performances.These findings provided food industry with exciting opportunities to develop ‘clean‐label’ emulsions with desirable properties. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Lycophytes and ferns represent one of the earliest-diverging lineages of vascular plants, with the Lycopodiaceae family constituting the basal clade among lycophytes. In this research, we successfully assembled and annotated the complete Lycopodium japonicum Thunb. (L. japonicum) mitochondrial genome (mitogenome) utilizing PacBio HiFi sequencing data, resulting in a single circular molecule with a size of 454,458 bp. 64 unique genes were annotated altogether, including 34 protein-coding genes, 27 tRNAs and 3 rRNAs. It also contains 32 group II introns, all of which undergo cis-splicing. We identified 195 simple sequence repeats, 1,948 dispersed repeats, and 92 tandem repeats in the L. japonicum mitogenome. Collinear analysis indicated that the mitogenomes of Lycopodiaceae are remarkably conserved compared to those of other vascular plants. We totally identified 326 RNA editing sites in 31 unique protein-coding genes with 299 sites converting cytosine to uracil and 27 sites the reverse. Notably, the L. japonicum mitogenome has small amounts foreign DNA from plastid or nuclear origin, accounting for only 2.81% of the mitogenome. The maximum likelihood phylogenetic analysis based on 23 diverse land plant mitogenomes and plastid genomes supports the basal position of lycophytes within vascular plants and they form a sister clade to all other vascular lineages, which is consistent with the PPG I classification system. As the first reported mitogenome of Lycopodioideae subfamily, this study enriches our understanding of Lycopodium mitogenomes, and sets the stage for future research on mitochondrial diversity and evolution within the lycophytes and ferns. [ABSTRACT FROM AUTHOR]

Cyclic polymers, which are found in the field of biopolymers, exhibit unique physical properties such as suppressed molecular mobility. Considering thermodynamics, the suppressed molecular mobility of cyclic polymers is expected to prevent unfavorable entropy loss in molecular interactions. In this study, we synthesized cyclic glycopolymers carrying galactose units and investigated the effects of their molecular mobility on the interactions with a lectin (peanut agglutinin). The synthesized cyclic glycopolymers exhibited delayed elution time on size exclusion chromatography and a short spin‐spin relaxation time, indicating typical characteristics of cyclic polymers, including smaller hydrodynamic size and suppressed molecular mobility. The hemagglutination inhibition assay revealed that the cyclic glycopolymers exhibited weakened interactions with peanut agglutinin compared to the linear counterparts, attributable to the suppressed molecular mobility. Although the results are contrary to our expectations, the impact of polymer topology on molecular recognition remains intriguing, particularly in the context of protein repellent activity in the biomedical field. [ABSTRACT FROM AUTHOR]

The U-box family encodes E3 ubiquitin ligase, which can specifically recognize the substrate and thus regulate the process of protein modification and degradation. In order to identificate the members of the Physcomitrium patens U-box family and to analyze their gene expression regularities, their physicochemical characteristics, evolutionary relationship, cis-acting element, tissue expression patterns and stress response were analyzed based on the whole sequencing data of P. patens through bioinformatics technology. The results were as follows: (1) A total of 31 U-box family members were identified in the whole genome of P. patens and were unevenly distributed on 14 chromosomes; their molecular weight sizes ranged from 37.75-117.49 kDa, and their isoelectric points ranged from 5.32-8.55. (2) The evolutionary tree showed that the U-box family members of P. patens were distributed in subfamilies I-IX, among which subfamily Ⅶ contained the largest number of members, with a total of 11 members accounting for about 36.67%. This indicated that P. patens was highly conserved and functionally diversified in the historical evolutionary process. (3) Promoter analysis yielded that P. patens U-box family members had elements that binded several hormones including GA and ABA. (4) Tissue expression analysis yielded that P. patens U-box family members was abundantly expressed mainly in the chloroplast, axoplast, and sporophyte S3 periods. (5) After simulated drought treatment with ABA, mannitol and saturated LiCl, it was found that the proposed stems of gametophytes were yellowed and the expression of PpPUB21 was significantly induced. It is hypothesized that the P. patens U-box family members plays an important role in growth and development and in response to adversity stress, and these findings provide a reference for further research on the U-box gene of P. patens. [ABSTRACT FROM AUTHOR]

Textile wastewater containing dyes poses significant environmental hazards. Advanced oxidative processes, especially the heterogeneous photo-Fenton process, are effective in degrading a wide range of contaminants due to high conversion rates and ease of catalyst recovery. This study evaluates the heterogeneous photodegradation of the azo dyes Acid Red 18 (AR18), Acid Red 66 (AR66), and Orange 2 (OR2) using magnetite as a catalyst. The magnetic catalyst was synthesized via a hydrothermal process at 150 °C. Experiments were conducted at room temperature, investigating the effect of catalyst dosage, pH, and initial concentrations of H2O2 and AR18 dye. Kinetic and thermodynamic studies were performed at 25, 40, and 60 °C for the three azo dyes (AR18, AR66, and OR2) and the effect of the dye structures on the degradation efficiency was investigated. At 25 °C for 0.33 mmolL−1 of dye at pH 3.0, using 1.4 gL−1 of the catalyst and 60 mgL−1 of H2O2 under UV radiation of 16.7 mWcm−2, the catalyst showed 62.3% degradation for AR18, 79.6% for AR66, and 83.8% for OR2 in 180 min of reaction. The oxidation of azo dyes under these conditions is spontaneous and endothermic. The pseudo-first-order kinetic constants indicated a strong temperature dependence with an order of reactivity of the type OR2 > AR66 > AR18, which is associated with the molecular size, steric hindrance, aromatic conjugation, electrostatic repulsion, and nature of the acid–base interactions on the catalytic surface. [ABSTRACT FROM AUTHOR]

Understanding the properties of nano-confined gas is essential for the effective utilization of unconventional natural gas, but the classical equation of state (EOS) for bulk gas does not apply to nano-confined gas. In this work, based on the potential energy of nano-confined gas molecules, the gas density distribution function on a nano-pore cross section is derived and subsequently, a novel van der Waals (vdW) EOS is proposed that modifies the "internal pressure" term and extends the "external pressure" term. In this proposed EOS, the gas/solid and porous media properties, such as pore size, gas molecular size, solid molecular number density, and the gas–solid molecular interaction parameter, are applied to characterize the nano-confinement effect. Using the experimental results of nano-confined gas critical temperature, the applicability of this proposed vdW EOS model is verified and it has the largest relative deviation of 7% for nanopores with sizes greater than 2 nm. The gas molecular size and gas–solid molecular interaction are found to be important factors contributing to the nano-confinement effect, and they influence the critical point shift and density of nano-confined gas. Also, the solid molecular number density greatly affects the compressibility of nano-confined gas. Using this model, the U-shaped density distribution curve described in molecular dynamic simulations is obtained, and the equation to calculate the adsorption layer thickness is also obtained. The nano-confinement effect induces gas liquefaction and incompressibility because of the increased gas density and increased compressibility factor of nano-confined gas. [ABSTRACT FROM AUTHOR]